Silicon carbide(SiC)high-voltage,high-power semiconductor devices are essential for next-generation power systems,yet conventional silicone elastomer encapsulation materials suffer from insulation degradation under ex...Silicon carbide(SiC)high-voltage,high-power semiconductor devices are essential for next-generation power systems,yet conventional silicone elastomer encapsulation materials suffer from insulation degradation under extreme thermal and electrical stresses,highlighting the critical need for novel dielectric materials.This article brings phenyl groups into the side group of conventional silicone elastomers through ring-opening polymerisation and hydrosilylation,developing phenyl-modified silicone elastomers.The material's superior thermal resistance is substantiated through thermal ageing and thermogravimetric analysis.Moreover,this study delineates the insulating robustness of the material by gauging its dielectric breakdown voltage.By subjecting the material to pulse electric fields,we investigate the insulating properties of the encapsulation material under operational conditions reflective of actual service environments.Dielectric testing and molecular electrostatic potential simulations are further employed to analyse the enhancement of the material's insulating properties due to the introduction of phenyl groups.Research studies indicate that phenyl silicone elastomers exhibit outstanding temperature and electrical resistance,performing well under pulsed electric field.This is associated with the phenyl group's rigid structure,conjugated system,and its electron-withdrawing characteristics.Study provides a theoretical foundation for improving the insulating properties of encapsulation materials and the operational reliability of power electronic devices.展开更多
Traditional mineral oil has long served as a liquid insulating medium in power transformers.However,its low fire resistance,poor biodegradability and dependence on finite fossil fuel resources,along with its low flash...Traditional mineral oil has long served as a liquid insulating medium in power transformers.However,its low fire resistance,poor biodegradability and dependence on finite fossil fuel resources,along with its low flash point,contribute to transformer explosions and fires.To overcome these limitations,developing insulating liquids with high flash points and self-extinguishing properties is essential.Although natural ester-based insulating oils and silicone oils have been proposed as alternatives,their performance requires further optimisation,and their application in transformers remains challenging.This study examines the combustion characteristics of three novel self-extinguishing fluorinated silicone oils using combustion experiments and reactive molecular dynamics simulations.The results demonstrate that methylfluorinated and hydrofluorinated silicone oils exhibit superior self-extinguishing performance compared to mineral oil and natural ester-based insulating oils.Simulation analyses indicate that fluorinated silicone oils generate silicon-oxygen polymers upon ignition,which influence subsequent chain reactions.However,hydroxyfluorinated silicone oil releases a higher concentration of key free radicals,intensifying chain reactions and diminishing its self-extinguishing capability.As a result,its self-extinguishing performance is significantly weaker than that of methylfluorinated and hydrofluorinated silicone oils.These findings provide valuable insights for the development of advanced liquid insulating media as potential replacements for mineral oil.展开更多
Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability an...Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability and short service life.To address these issues,low-phenyl silicone rubber was prepared and tested,and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.Design/methodology/approach–The low-temperature resistance and thermal stability of the prepared lowphenyl silicone rubber were studied using low-temperature tensile testing,differential scanning calorimetry,dynamic thermomechanical analysis and thermogravimetric analysis.The sealing performance of the lowphenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.Findings–The prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability.According to the finite element analysis results,the finish of the flange sealing surface and groove outer edge should be ensured,and extrusion damage should be avoided.The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments.When the sealing effect was ensured,a small compression ratio should be selected,and rubbers with hardness and elasticity less affected by temperature should be selected.The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature(RT)and�508C.Originality/value–The innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.展开更多
Silicone rubber(SR)is a versatile material widely used across various advanced functional applications,such as soft actuators and robots,flexible electronics,and medical devices.However,most SR molding methods rely on...Silicone rubber(SR)is a versatile material widely used across various advanced functional applications,such as soft actuators and robots,flexible electronics,and medical devices.However,most SR molding methods rely on traditional thermal processing or direct ink writing three-dimensional(3D)printing.These methods are not conducive to manufacturing complex structures and present challenges such as time inefficiency,poor accuracy,and the necessity of multiple steps,significantly limiting SR applications.In this study,we developed an SR-based ink suitable for vat photopolymerization 3D printing using a multi-thiol monomer.This ink enables the one-step fabrication of complex architectures with high printing resolution at the micrometer scale,providing excellent mechanical strength and superior chemical stability.Specifically,the optimized 3D printing SR-20 exhibits a tensile stress of 1.96 MPa,an elongation at break of 487.9%,and an elastic modulus of 225.4 kPa.Additionally,the 3D-printed SR samples can withstand various solvents(acetone,toluene,and tetrahydrofuran)and endure temperatures ranging from-50℃ to 180℃,demonstrating superior stability.As a emonstration of the application,we successfully fabricated a series of SR-based soft pneumatic actuators and grippers in a single step with this technology,allowing for free assembly for the first time.This ultraviolet-curable SR,with high printing resolution and exceptional stability performance,has significant potential to enhance the capabilities of 3D printing for applications in soft actuators,robotics,flexible electronics,and medical devices.展开更多
Tracheal collapse(TC),defined by excessive tracheal collapsibility,often results in severe respiratory distress in small-breed dogs.Surgical intervention,including the placement of extraluminal stents,has been employe...Tracheal collapse(TC),defined by excessive tracheal collapsibility,often results in severe respiratory distress in small-breed dogs.Surgical intervention,including the placement of extraluminal stents,has been employed as a treatment option.Owing to the anatomical and physiological similarities between rabbit and canine tracheas,a rabbit model was utilized to develop a novel extraluminal silicone tracheal stent and evaluate its feasibility in treating tracheomalacia.The stent was surgically implanted in eight New Zealand White rabbits after the induction of tracheomalacia.Postoperative evaluations,including clinical assessment,radiography,computed tomography(CT),and histological analysis,were performed at 1,2,and 6 months post-implantation.All rabbits in the stent group survived without exhibiting signs of respiratory distress,whereas all rabbits in the tracheomalacia group experienced respiratory distress,with one succumbing to respiratory failure.Radiographic and CT evaluations confirmed that the stent effectively maintained airway patency,with tracheal measurements not significantly different from the preoperative values,indicating successful restora-tion of tracheal diameter.Histological analysis demonstrated minimal inflammatory response,the absence of fibrosis,and preserved structural integrity of the tracheal cartilage.Therefore,the novel extraluminal silicone tracheal stent provides effective airway support while minimizing adverse tissue reactions.Further studies,including the use of this stent in a canine TC model and assessment of its long-term outcomes,are warranted to explore its potential clinical applications in veterinary medicine.展开更多
BACKGROUND Silicone oil(SiO)migration to the central nervous system(CNS)is a rare complication of SiO tamponade after vitreo-retinal surgeries,it could masquerade hemorrhage on computed tomography neuro-imaging.Only l...BACKGROUND Silicone oil(SiO)migration to the central nervous system(CNS)is a rare complication of SiO tamponade after vitreo-retinal surgeries,it could masquerade hemorrhage on computed tomography neuro-imaging.Only limited cases were reported in the literature,certain intra-operative and post-operative ocular risk factors might contribute to the different extend of SiO migration in the CNS.AIM To study the risk factors for cerebral ventricular migration(CVM)on top of visual pathway migration(VPM).METHODS Conforming to the preferred reporting items for systematic reviews and metaanalyses guidelines,literature searches on PubMed,MEDLINE,EMBASE were performed on June 1,2024.Publications on SiO migration to CNS were included in this review.Non-English articles,and studies without neuro-imaging of the CNS were excluded.Patient demographics,SiO filled eyes'ocular characteristics and vitrectomy surgical details were extracted from included studies in this review.VPM and CVM were assigned as group 1 and group 2 respectively.Fisher's exact tests,Mann-Whitney U tests and binary logistic regression were performed.RESULTS Total 68 articles were obtained after searches,48 publications were included for analysis.Total 54 SiO filled eyes were analyzed.Post-vitrectomy intraocular pressure(IOP)was found to be significant in both Mann-Whitney U test(P=0.047)and binary logistic regression(P=0.012).Diabetic was found to be significant in binary logistic regression(P=0.037),but at borderline risk for CVM in Fisher's exact test(P=0.05).Other significant factors include longer SiO tamponade time(P=0.002 in Fisher's exact test)and visual acuity(P=0.011 in binary logistic regression).Optic nerve atrophy or disc cupping(P=1.00,P=0.790)and congenital optic disc anomalies(P=0.424)were all with P>0.05.CONCLUSION SiO migration to CNS is rare with limited case reports only.Our analysis of the existing literature demonstrated higher post-vitrectomy IOP was associated with CVM,followed by patients’diabetic status,longer SiO tamponade time and visual acuity.Optic nerve atrophy,disc cupping and congenital optic disc anomalies were not associated.Modifiable risk factors of post-vitrectomy IOP and SiO tamponade time should be closely monitored by vitreoretinal surgeons.Lower IOP target post-vitrectomy and earlier SiO removal surgeries should be arranged.展开更多
Fluorination is a critical surface modification technique for enhancing the electrical performance of composite insulators.This study employs molecular simulations to examine the microstructure and space charge behavi...Fluorination is a critical surface modification technique for enhancing the electrical performance of composite insulators.This study employs molecular simulations to examine the microstructure and space charge behavior of fluorinated and non-fluorinated silicone rubber under an electric field,with experimental validation.The results show that fluorinated silicone rubber exhibits lower total energy,higher polarization,and stronger dipole moments compared to its non-fluorinated counterpart,shifting the material from an insulating to a conductive state.Under lower electric field strengths,the carbon-silicon bonds in fluorinated silicone rubber are longer,but it maintains geometric stability under higher fields.The energy gap changes across different fluorination modes and varies with electric field strength,indicating that fluorination affects conductivity differently at various field intensities.Both fluorination methods improve conductivity in the 0–3.8 V/nm range,with substitutional fluorination showing superior performance between 3.8 and 8.9 V/nm.Above 9.1 V/nm,fluorination maximizes conductivity.The fluorinated samples exhibit a greater redshift at higher electric fields,resulting in enhanced conductivity and improved surface charge distribution.These findings offer insights into the microscopic effects of fluorination on silicone rubber’s electrical properties,while experiments confirm that fluorination increases hydrophobicity and boosts DC flashover voltage,further enhancing the material’s performance.展开更多
Wearable bioelectronic devices are rapidly evolving towards miniaturization and multifunctionality,with remarkable features such as flexibility and comfort.However,achieving a sustainable power supply for wearable bio...Wearable bioelectronic devices are rapidly evolving towards miniaturization and multifunctionality,with remarkable features such as flexibility and comfort.However,achieving a sustainable power supply for wearable bioelectronic devices is still a great challenge.Triboelectric nanogenerators(TENGs)provide an efficient solution by converting irregular,low-frequency bioenergy from the human body into electrical energy.Beyond sustainably powering wearable bioelectronics,the harvested electrical energy also carries rich information for human body sensing.In this conversion process,the choice of material plays a crucial role in affecting the output performance of the TENGs.Among various materials,silicone rubber(SR)stands out due to its exceptional plasticity,flexibility,comfortability and other favorable properties.Moreover,with appropriate treatment,SR can achieve extreme functionalities such as high robustness,good stability,self-healing capabilities,rapid response,and more.In this review,recent advances in wearable SR-based TENGs(SR-TENGs)are systematically reviewed with a focus on their application in different parts of the human body.Given that the manufacturing method of SR-TENGs largely determines its output performance and sensitivity,this paper introduces the design of SR-TENGs,including material selection,process modulation,and structure optimization.Additionally,this article discusses the current challenges in the SR-TENG fabrication technology and potential future directions,aiming to promote the effective development of SR-TENGs in biomechanical energy harvesting and self-powered sensing applications.展开更多
Laminated elastomeric bearings used in seismic isolation rely on the mechanical properties of their constituent elastomers to ensure effective performance.However,despite their resistance to temperature fluctuations a...Laminated elastomeric bearings used in seismic isolation rely on the mechanical properties of their constituent elastomers to ensure effective performance.However,despite their resistance to temperature fluctuations and environmental aggressors,silicone elastomers exhibit relatively low stiffness,limiting their direct applicability in seismic isolation.This study investigates the effect of fumed silica as a reinforcing filler to enhance the mechanical properties of laminated silicone elastomeric bearings.Elastomeric samples were fabricated with varying fumed silica proportions and subjected to Shore A hardness,uniaxial tensile,and lap shear tests to assess the influence of filler content.Additionally,quasi-static tests were conducted on reduced-scale bearing prototypes under combined vertical compression and cyclic horizontal shear to evaluate their seismic isolation performance.The results demonstrate that fumed silica reinforcement significantly increases stiffness,as evidenced by higher Shore A hardness values.However,a trade-off was observed in tensile properties,with reductions in tensile strength and elongation at break.Despite this,the equivalent elastic modulus did not show substantial variation up to large deformations,indicating that stiffness is preserved under most working conditions.Lap shear tests showed that fumed silica improves shear resistance,while quasi-static tests revealed inelastic behavior with small increases in equivalent shear coefficients but no substantial loss in damping ratios.These findings suggest that fumed silica reinforcement enhances silicone elastomers’stiffness and shear resistance while maintaining moderate damping properties,making it a promising approach for improving the mechanical performance of elastomeric bearings in seismic isolation applications.展开更多
In the production process of silicone sealant,mineral oil is used to replace methyl silicone oil plasticizer in silicone sealant to reduce costs and increase efficiency.However,the silicone sealant content in mineral ...In the production process of silicone sealant,mineral oil is used to replace methyl silicone oil plasticizer in silicone sealant to reduce costs and increase efficiency.However,the silicone sealant content in mineral oil is prone to premature aging,which significantly reduces the mechanical properties of the silicone sealant and severely affects its service life.At the same time,there are few reports on the simulation research of the performance of silicone sealant.In this study,three mixed system models of crosslinking silicone sealant/plasticizer are constructed by the molecular dynamics simulationmethod,and the effect of three influencing factors,namely,crosslinking degree of silicone sealant,plasticizer content and external temperature on the mechanical properties of silicone sealant system is analyzed.The results show that at room temperature,the mechanical properties of the silicone sealant system are enhanced with the increase of its crosslinking degree;At a high crosslinking degree,with the increase of plasticizer content,themechanical properties of the silicone sealant system show an overall decreasing trend.When the methyl silicone oil in the range of 20%,themechanical properties of the silicone sealant appeared tobe a small degree of enhancement;As the temperature increases,the doped mineral oil mechanical properties of silicone sealant declined significantly,while doped with methyl silicone oil silicone sealant and doped with double-ended vinyl silicone oil silicone sealant mechanical properties have better heat resistance.It will provide scientific theoretical guidance for improving and predicting the mechanical properties of silicone sealant.展开更多
With the increasing and refined applications of silicone rubber devices in the biomedical field,it is of great significance to accurately describe and predict the mechanical behavior of them under large deformation.Th...With the increasing and refined applications of silicone rubber devices in the biomedical field,it is of great significance to accurately describe and predict the mechanical behavior of them under large deformation.This paper finds that after con-sidering the influence of higher-order shear strain on the normal stress,the Poynting effect in ribbed silicone rubber tubes with certain cross-sectional shapes exhibits a new phenomenon―a non-monotonic trend between axial deformation and twist angle.This paper develops a nonlinear finite element program for simulating large deformations of hyperelastic materials,and studies the Poynting effect in ribbed circular tubes of twisted silicone rubber.The results show that in the ribbed circular tubes with a porosity between 12% and 40%(with the number of ribs ranging from 12 to 26),there appears a normal to reverse conversion of the Poynting effect,that is,the axial extension ratio first decreases and then increases during a monotonic loading process,indicating that the influence of higher-order shear strain on normal stress cannot be ignored when the cross-sectional shape is complex.Especially in ribbed circular tubes with about 20% porosity,a substantial change of axial normal strain from−0.035% to 0.035% can be achieved within a twist angle range of 180°.Based on this,the quantitative influence of higher-order shear strain on normal stress is studied.These research results provide a theoretical basis for accurately controlling the axial expansion and contraction of twisted parts and indicate that a normal to reverse conversion of the Poynting effect can be implemented by designing the cross-sectional shape under certain conditions.展开更多
High-efficient rubber antioxidants for enhanced heat resistance without compromising mechanical properties remain an enormous and long-term challenge for the rubber industry.Herein,we employed the in-situ growth of Ce...High-efficient rubber antioxidants for enhanced heat resistance without compromising mechanical properties remain an enormous and long-term challenge for the rubber industry.Herein,we employed the in-situ growth of Ce-doped Co-metal-organic framework(Ce Co-MOF)in dendritic mesoporous organosilica nanoparticles(DMONs@Ce Co-MOF,denoted as DCCM)to prepare a novel antioxidant that exhibit outstanding thermal stability.Dendritic mesoporous organosilica nanoparticles(DMONs)effectively alleviated the incompatibility of Ce Co-MOF in the polymer matrix,and the effective scavenging of free radicals was attributed to the various oxidation states of metal ions in Ce Co-MOF.Surprising,by adding only0.5 phr(parts per hundred of rubber)of DMONs@Ce Co-MOF to silicone rubber,(SR),the retention rate of tensile strength increased from 37.3%to 61.6%after aging 72 h at 250℃,and the retention rate of elongation at break of DCCM/SR1 composites reached 68%,which was 5.43 times of SR.The strategy of anchoring MOFs on the surface of silica also provides a viable method for preparing effective compound functionalized rubber antioxidant.展开更多
Silicone rubber(SR)exhibits superior breathability and high-temperature resistance.However,SR is prone to degradation under extreme heat or combustion,limiting its effectiveness in mitigating secondary hazards.In this...Silicone rubber(SR)exhibits superior breathability and high-temperature resistance.However,SR is prone to degradation under extreme heat or combustion,limiting its effectiveness in mitigating secondary hazards.In this study,phosphate glass powder was used to calcinate zinc borate,lanthanum oxide,and cerium oxide.Methylphenyl polysiloxane was then grafted onto the surface of the glass powder,resulting in the modified pow-ders designated as Methylphenyl polysiloxane-grafted zinc borate-modified phosphate glass powder(GF-ZnBM),Methylphenyl polysiloxane-grafted lanthanum oxide-modified phosphate glass powder(GF-LaM),and Methylphenyl polysiloxane-grafted cerium oxide-modified phosphate glass powder(GF-CeM).The modified powders were sub-sequently incorporated into silicone rubber composites to enhance the ceramicization capability of silicone rubber at high temperatures.Specifically,GF-CeM and GF-LaM significantly increased the limiting oxygen index(LOI)to 33%and reduced the tendency for combustion propagation.Additionally,GF-CeM notably contributed to enhancing ceramicization strength.The presence of cerium oxide helps in the melting of the glass powder and enhances its adhesion to the silicone rubber matrix.SR/ZnB-GF exhibited the lowest activation energy among the tested composites,along with the best protective capability.The inclusion of modified glass powder has a minor impact on the rheological properties,indicating that the composite retains its ability to flow and deform under stress.This confirms that the material remains flexible under normal conditions and forms a ceramic structure when heated,thereby exhibiting self-supporting properties.This study provides a practical methodology for the targeted modification of glass powders,thereby further enhancing the fire safety of silicone-based composites.展开更多
Two-phase partitioning bioreactors(TPPBs)have been widely used because they overcome the mass-transfer limitation of hydrophobic volatile organic compounds(VOCs)in waste gas biological treatments.Understanding the mec...Two-phase partitioning bioreactors(TPPBs)have been widely used because they overcome the mass-transfer limitation of hydrophobic volatile organic compounds(VOCs)in waste gas biological treatments.Understanding the mechanisms of mass-transfer enhancement in TPPBs would enable efficient predictions for further industrial applications.In this study,influences of gradually increasing silicone oil ratio on the TPPB was explored,and a 94.35%reduction of the n-hexane partition coefficient was observed with 0.1 vol.%silicone,which increased to 80.7%along with a 40-fold removal efficiency enhancement in the stabilised removal period.The elimination capacity increased from 1.47 to 148.35 g/(m^(3)·h),i.e.a 101-fold increase compared with that of the single-phase reactors,when 10 vol.%(3 Critical Micelle Concentration)silicone oil was added.The significantly promoted partition coefficient was the main reason for the mass transfer enhancement,which covered the negative influences of the decreased total mass-transfer coefficient with increasing silicone oil volume ratio.The gradually rising stirring rate was benefit to the n-hexane removal,which became negative when the dominant resistance shifted from mass transfer to biodegradation.Moreover,a mass-transfer-reaction kinetic model of the TPPB was constructed based on the balance of n-hexane concentration,dissolved oxygen and biomass.Similar to the mechanism,the partition factor was predicted sensitive to the removal performance,and another five sensitive parameters were found simultaneously.This forecasting method enables the optimisation of TPPB performance and provides theoretical support for hydrophobic VOCs degradation.展开更多
AIM:To elucidate the manifestations and associated complications observed in patients with intraocular silicone oil(SO)emulsification through multiple imaging modalities.METHODS:This single-center,observational,retros...AIM:To elucidate the manifestations and associated complications observed in patients with intraocular silicone oil(SO)emulsification through multiple imaging modalities.METHODS:This single-center,observational,retrospective study included 116 patients who underwent pars plana vitrectomy(PPV)with SO injection for retinal detachment(RD),followed by subsequent SO removal at the Second Hospital of Hebei Medical University from January 2013 to January 2023.Comprehensive records of ophthalmic examinations utilizing multiple imaging techniques were maintained.RESULTS:The study comprised 56 females and 60 males,with a mean age of 52.75±13.6y.The mean follow-up duration for SO tamponade was 9.04±11.33mo(range:1-84mo).Among the participants,59 patients were diagnosed with SO emulsification,while 57 patients were in the SO unemulsified group.Patients with SO emulsification had a significantly prolonged SO tamponade duration(P<0.01).Multiple imaging techniques revealed notable signs of SO emulsification and its complications,such as 4 cases(3.4%)with posterior corneal SO-like keratic precipitates(KP)observed by anterior segment photography,23 cases(19.8%)exhibiting spherical high-reflection signals in the inter-retina,retinal pigment epithelium,or choroid detected by Spectralis spectral domain optical coherence tomography(SD-OCT),4 cases(3.4%)showing slow movement of emulsified SO droplets within retinal vessels during fluorescein angiography(FFA),plain and enhanced head magnetic resonance imaging(MRI)images of these four patients did not detect emulsified SO in the lateral ventricles,suprasellar cistern,subarachnoid space,third ventricle,fourth ventricle,or other intracranial locations.CONCLUSION:Intraocular emulsified SO can lead to damage in both anterior and posterior segment tissues,encompassing corneal degeneration,cataracts,glaucoma,retinal and choroid inflammation.Objective multiple imaging techniques such as anterior segment photography,SD-OCT,FFA,and MRI offer comprehensive evaluation and diagnosis of SO emulsification and its associated complications.展开更多
Silicone material extrusion(MEX)is widely used for processing liquids and pastes.Owing to the uneven linewidth and elastic extrusion deformation caused by material accumulation,products may exhibit geometric errors an...Silicone material extrusion(MEX)is widely used for processing liquids and pastes.Owing to the uneven linewidth and elastic extrusion deformation caused by material accumulation,products may exhibit geometric errors and performance defects,leading to a decline in product quality and affecting its service life.This study proposes a process parameter optimization method that considers the mechanical properties of printed specimens and production costs.To improve the quality of silicone printing samples and reduce production costs,three machine learning models,kernel extreme learning machine(KELM),support vector regression(SVR),and random forest(RF),were developed to predict these three factors.Training data were obtained through a complete factorial experiment.A new dataset is obtained using the Euclidean distance method,which assigns the elimination factor.It is trained with Bayesian optimization algorithms for parameter optimization,the new dataset is input into the improved double Gaussian extreme learning machine,and finally obtains the improved KELM model.The results showed improved prediction accuracy over SVR and RF.Furthermore,a multi-objective optimization framework was proposed by combining genetic algorithm technology with the improved KELM model.The effectiveness and reasonableness of the model algorithm were verified by comparing the optimized results with the experimental results.展开更多
Nano-enabled silicone-rubber articles for feeding or chewing could be a source of metallic nanoparticles(NPs)directly exposed to infants and young children.However,the impact of steam disinfection on release of NPs an...Nano-enabled silicone-rubber articles for feeding or chewing could be a source of metallic nanoparticles(NPs)directly exposed to infants and young children.However,the impact of steam disinfection on release of NPs and the related potential risks to children's health are unknown.Here,we investigated contents and form of Ag and Zn in 57 nano-enabled silicone-rubber baby bottle teats,pacifiers,and teethers of seven countries and examined the impacts of steam disinfection on in vitro bioaccessibility(IVBA)of Ag and Zn in the articles.Nearly 89%articles had a mixture of Ag-and Zn-containing NPs and the teethers had relatively high Ag and Zn contents(up to 501 and 254μg/g,respectively).Steam disinfection caused rubber decomposition into micro(nano)plastics(0.54-15.7μm)and NP release from the interior of bulk rubber and micro-sized plastics,thus enhancing the IVBA of Ag and Zn by up to 5.5 times.The findings provide insights into mechanisms for NP release by steam disinfection.Though oral exposure risk assessment suggested low health concerns on individual metal release,our study points out the need to assess the potential health risks of child co-exposure to metallic NPs and micro(nano)plastics.展开更多
AIM:To evaluate the efficacy and safety of silicone oil(SO)as a corneal lubricant to improve visualization during vitrectomy.METHODS:Patients who underwent vitreoretinal surgery were divided into two groups.Group 1 wa...AIM:To evaluate the efficacy and safety of silicone oil(SO)as a corneal lubricant to improve visualization during vitrectomy.METHODS:Patients who underwent vitreoretinal surgery were divided into two groups.Group 1 was operated on with initial SO(Oxane 5700)as a corneal lubricant.Group 2 was operated on with initial lactated ringer’s solution(LRS)and then replaced with SO as required.Fundus clarity was scored during the surgery.Fluorescein staining was performed to determine the damage to corneal epithelium.RESULTS:Totally 114 eyes of 114 patients were included.Single SO use maintained a clear cornea and provided excellent visualization of surgical image.In group 1,the fundus clarity was grade 3 in 41/45 eyes and grade 2 in 4/45 eyes.In group 2,corneal edema frequently occurred after initial LRS use.The fundus clarity was grade 3 in 19/69 eyes,2 in 37/69 eyes and 1 in 13/69 eyes(P<0.05).SO was applied in 29 eyes of initial LRS use with subsequent corneal edema,which eliminated the corneal edema in 26 eyes.Corneal fluorescein staining score in group 1 was 0 in 28 eyes,1 in 11 eyes and 2 in 6 eyes,and 40,20 and 9,respectively,in group 2(all P>0.05).CONCLUSION:The use of SO as a corneal lubricant is effective and safe for preserving and improving corneal clarity and providing clear surgical field during vitrectomy.展开更多
AIM:To evaluate scleral buckling(SB)surgery using a noncontact wide-field viewing system and 23-gauge intraocular illumination for the treatment of rhegmatogenous retinal detachment in silicone oil(SO)-filled eyes.MET...AIM:To evaluate scleral buckling(SB)surgery using a noncontact wide-field viewing system and 23-gauge intraocular illumination for the treatment of rhegmatogenous retinal detachment in silicone oil(SO)-filled eyes.METHODS:Totally 9 patients(9 eyes)with retinal detachment in SO-filled eyes were retrospectively analyzed.All patients underwent non-contact wide-field viewing system-assisted buckling surgery with 23-gauge intraocular illumination.SO was removed at an appropriate time based on recovery.The patients were followed up for at least 3mo after SO removal.Retinal reattachment,complications,visual acuity and intraocular pressure(IOP)before and after surgery were observed.RESULTS:Patients were followed up for a mean of 8.22mo(3-22mo)after SO removal.All patients had retinal reattachment.At the final follow-up,visual acuity showed improvement for 8 patients,and no change for 1 patient.The IOP was high in 3 patients before surgery,but it stabilized after treatment;it was not affected in the other patients.None of the patients had infections,hemorrhage,anterior ischemia,or any other complication.CONCLUSION:This new non-contact wide-field viewing system-assisted SB surgery with 23-gauge intraocular illumination is effective and safe for retinal detachment in SO-filled eyes.展开更多
SiO_(2)-particle reinforced silicon rubber composite(SP-RSRC)is a widely utilized material that offers shock absorption protection to various engineering structures in impact environments.This paper presents a compreh...SiO_(2)-particle reinforced silicon rubber composite(SP-RSRC)is a widely utilized material that offers shock absorption protection to various engineering structures in impact environments.This paper presents a comprehensive investigation of the mechanical behavior of SP-RSRC under various strain rates,employing a combination of experimental,theoretical,and numerical analyses.Firstly,quasi-static and dynamic compression tests were performed on SP-RSRC utilizing a universal testing machine and split Hopkinson pressure bar(SHPB)apparatus.Nonlinear stress-strain relationships of SP-RSRC were obtained for strain rates ranging from 1×10^(−3) to 3065 s^(−1).The results indicated that the composite showed evident strain rate sensitivity,along with nonlinearity.Then,a nonlinear visco-hyperelastic constitutive model was developed,consisting of a hyperelastic component utilizing the 3rd-order Ogden energy function and a viscous component employing a rate-dependent relaxation time scheme.The model accurately characterized the dynamic mechanical response of SP-RSRC,effectively mitigating the challenge of calibrating an excessive number of material parameters inherent in conventional viscoelastic models.Furthermore,the simplified rubber material(SRM)model,integrated within the LS-DYNA software,was chosen to depict the mechanical properties of SP-RSRC in numerical simulations.The parameters of the SRM model were further calibrated based on the strain-stress relationships of SP-RSRC,as predicted by the developed nonlinear visco-hyperelastic constitutive model.Finally,an inverse ballistic experiment using a single-stage air gun was conducted for SP-RSRC.Numerical simulations of SHPB experiments and the inverse ballistic experiment were then performed,and the reliability of the calibrated SRM model was verified by comparing the results of experiments and numerical simulations.This study offers a valuable reference for the utilization of SP-RSRC in the realm of impact protection.展开更多
基金National Natural Science Foundation of China(Grants 52277155,52177183).
文摘Silicon carbide(SiC)high-voltage,high-power semiconductor devices are essential for next-generation power systems,yet conventional silicone elastomer encapsulation materials suffer from insulation degradation under extreme thermal and electrical stresses,highlighting the critical need for novel dielectric materials.This article brings phenyl groups into the side group of conventional silicone elastomers through ring-opening polymerisation and hydrosilylation,developing phenyl-modified silicone elastomers.The material's superior thermal resistance is substantiated through thermal ageing and thermogravimetric analysis.Moreover,this study delineates the insulating robustness of the material by gauging its dielectric breakdown voltage.By subjecting the material to pulse electric fields,we investigate the insulating properties of the encapsulation material under operational conditions reflective of actual service environments.Dielectric testing and molecular electrostatic potential simulations are further employed to analyse the enhancement of the material's insulating properties due to the introduction of phenyl groups.Research studies indicate that phenyl silicone elastomers exhibit outstanding temperature and electrical resistance,performing well under pulsed electric field.This is associated with the phenyl group's rigid structure,conjugated system,and its electron-withdrawing characteristics.Study provides a theoretical foundation for improving the insulating properties of encapsulation materials and the operational reliability of power electronic devices.
基金supported by the National Natural Science Foundation of China(52407170)the Natural Science Foundation of Hubei Province(2024AFB306).
文摘Traditional mineral oil has long served as a liquid insulating medium in power transformers.However,its low fire resistance,poor biodegradability and dependence on finite fossil fuel resources,along with its low flash point,contribute to transformer explosions and fires.To overcome these limitations,developing insulating liquids with high flash points and self-extinguishing properties is essential.Although natural ester-based insulating oils and silicone oils have been proposed as alternatives,their performance requires further optimisation,and their application in transformers remains challenging.This study examines the combustion characteristics of three novel self-extinguishing fluorinated silicone oils using combustion experiments and reactive molecular dynamics simulations.The results demonstrate that methylfluorinated and hydrofluorinated silicone oils exhibit superior self-extinguishing performance compared to mineral oil and natural ester-based insulating oils.Simulation analyses indicate that fluorinated silicone oils generate silicon-oxygen polymers upon ignition,which influence subsequent chain reactions.However,hydroxyfluorinated silicone oil releases a higher concentration of key free radicals,intensifying chain reactions and diminishing its self-extinguishing capability.As a result,its self-extinguishing performance is significantly weaker than that of methylfluorinated and hydrofluorinated silicone oils.These findings provide valuable insights for the development of advanced liquid insulating media as potential replacements for mineral oil.
基金supported by the Science and Technology Research and Development Plan of the China State Railway Group Company Limited(No.Q2023J012).
文摘Purpose–The brake pipe system was an essential braking component of the railway freight trains,but the existing E-type sealing rings had problems such as insufficient low-temperature resistance,poor heat stability and short service life.To address these issues,low-phenyl silicone rubber was prepared and tested,and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.Design/methodology/approach–The low-temperature resistance and thermal stability of the prepared lowphenyl silicone rubber were studied using low-temperature tensile testing,differential scanning calorimetry,dynamic thermomechanical analysis and thermogravimetric analysis.The sealing performance of the lowphenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.Findings–The prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability.According to the finite element analysis results,the finish of the flange sealing surface and groove outer edge should be ensured,and extrusion damage should be avoided.The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments.When the sealing effect was ensured,a small compression ratio should be selected,and rubbers with hardness and elasticity less affected by temperature should be selected.The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature(RT)and�508C.Originality/value–The innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.
基金supported by the Strategic Priority Program of the Chinese Academy of Sciences(XDB0470303)the National Key R&D Program of China(2022YFB4600102and 2023YFE0209900)+4 种基金the National Natural Science Foundation of China(52175201 and 51935012)the science and technology projects of Gansu province(22JR5RA093,24JRRA044,24YFFA014 and 24ZDGA014)the Innovation and Entrepreneurship Team Project of YEDA(2021TD007)the special supporting project for provincial leading talents of Yantaithe Taishan Scholars Program。
文摘Silicone rubber(SR)is a versatile material widely used across various advanced functional applications,such as soft actuators and robots,flexible electronics,and medical devices.However,most SR molding methods rely on traditional thermal processing or direct ink writing three-dimensional(3D)printing.These methods are not conducive to manufacturing complex structures and present challenges such as time inefficiency,poor accuracy,and the necessity of multiple steps,significantly limiting SR applications.In this study,we developed an SR-based ink suitable for vat photopolymerization 3D printing using a multi-thiol monomer.This ink enables the one-step fabrication of complex architectures with high printing resolution at the micrometer scale,providing excellent mechanical strength and superior chemical stability.Specifically,the optimized 3D printing SR-20 exhibits a tensile stress of 1.96 MPa,an elongation at break of 487.9%,and an elastic modulus of 225.4 kPa.Additionally,the 3D-printed SR samples can withstand various solvents(acetone,toluene,and tetrahydrofuran)and endure temperatures ranging from-50℃ to 180℃,demonstrating superior stability.As a emonstration of the application,we successfully fabricated a series of SR-based soft pneumatic actuators and grippers in a single step with this technology,allowing for free assembly for the first time.This ultraviolet-curable SR,with high printing resolution and exceptional stability performance,has significant potential to enhance the capabilities of 3D printing for applications in soft actuators,robotics,flexible electronics,and medical devices.
文摘Tracheal collapse(TC),defined by excessive tracheal collapsibility,often results in severe respiratory distress in small-breed dogs.Surgical intervention,including the placement of extraluminal stents,has been employed as a treatment option.Owing to the anatomical and physiological similarities between rabbit and canine tracheas,a rabbit model was utilized to develop a novel extraluminal silicone tracheal stent and evaluate its feasibility in treating tracheomalacia.The stent was surgically implanted in eight New Zealand White rabbits after the induction of tracheomalacia.Postoperative evaluations,including clinical assessment,radiography,computed tomography(CT),and histological analysis,were performed at 1,2,and 6 months post-implantation.All rabbits in the stent group survived without exhibiting signs of respiratory distress,whereas all rabbits in the tracheomalacia group experienced respiratory distress,with one succumbing to respiratory failure.Radiographic and CT evaluations confirmed that the stent effectively maintained airway patency,with tracheal measurements not significantly different from the preoperative values,indicating successful restora-tion of tracheal diameter.Histological analysis demonstrated minimal inflammatory response,the absence of fibrosis,and preserved structural integrity of the tracheal cartilage.Therefore,the novel extraluminal silicone tracheal stent provides effective airway support while minimizing adverse tissue reactions.Further studies,including the use of this stent in a canine TC model and assessment of its long-term outcomes,are warranted to explore its potential clinical applications in veterinary medicine.
文摘BACKGROUND Silicone oil(SiO)migration to the central nervous system(CNS)is a rare complication of SiO tamponade after vitreo-retinal surgeries,it could masquerade hemorrhage on computed tomography neuro-imaging.Only limited cases were reported in the literature,certain intra-operative and post-operative ocular risk factors might contribute to the different extend of SiO migration in the CNS.AIM To study the risk factors for cerebral ventricular migration(CVM)on top of visual pathway migration(VPM).METHODS Conforming to the preferred reporting items for systematic reviews and metaanalyses guidelines,literature searches on PubMed,MEDLINE,EMBASE were performed on June 1,2024.Publications on SiO migration to CNS were included in this review.Non-English articles,and studies without neuro-imaging of the CNS were excluded.Patient demographics,SiO filled eyes'ocular characteristics and vitrectomy surgical details were extracted from included studies in this review.VPM and CVM were assigned as group 1 and group 2 respectively.Fisher's exact tests,Mann-Whitney U tests and binary logistic regression were performed.RESULTS Total 68 articles were obtained after searches,48 publications were included for analysis.Total 54 SiO filled eyes were analyzed.Post-vitrectomy intraocular pressure(IOP)was found to be significant in both Mann-Whitney U test(P=0.047)and binary logistic regression(P=0.012).Diabetic was found to be significant in binary logistic regression(P=0.037),but at borderline risk for CVM in Fisher's exact test(P=0.05).Other significant factors include longer SiO tamponade time(P=0.002 in Fisher's exact test)and visual acuity(P=0.011 in binary logistic regression).Optic nerve atrophy or disc cupping(P=1.00,P=0.790)and congenital optic disc anomalies(P=0.424)were all with P>0.05.CONCLUSION SiO migration to CNS is rare with limited case reports only.Our analysis of the existing literature demonstrated higher post-vitrectomy IOP was associated with CVM,followed by patients’diabetic status,longer SiO tamponade time and visual acuity.Optic nerve atrophy,disc cupping and congenital optic disc anomalies were not associated.Modifiable risk factors of post-vitrectomy IOP and SiO tamponade time should be closely monitored by vitreoretinal surgeons.Lower IOP target post-vitrectomy and earlier SiO removal surgeries should be arranged.
基金supported in part by the National Natural Science Foundation of China under Grant 52277139 and 52367014in part by the Guangxi Science Fund for Distinguished Young Scholars under Grant 2024GXNSFFA999017.
文摘Fluorination is a critical surface modification technique for enhancing the electrical performance of composite insulators.This study employs molecular simulations to examine the microstructure and space charge behavior of fluorinated and non-fluorinated silicone rubber under an electric field,with experimental validation.The results show that fluorinated silicone rubber exhibits lower total energy,higher polarization,and stronger dipole moments compared to its non-fluorinated counterpart,shifting the material from an insulating to a conductive state.Under lower electric field strengths,the carbon-silicon bonds in fluorinated silicone rubber are longer,but it maintains geometric stability under higher fields.The energy gap changes across different fluorination modes and varies with electric field strength,indicating that fluorination affects conductivity differently at various field intensities.Both fluorination methods improve conductivity in the 0–3.8 V/nm range,with substitutional fluorination showing superior performance between 3.8 and 8.9 V/nm.Above 9.1 V/nm,fluorination maximizes conductivity.The fluorinated samples exhibit a greater redshift at higher electric fields,resulting in enhanced conductivity and improved surface charge distribution.These findings offer insights into the microscopic effects of fluorination on silicone rubber’s electrical properties,while experiments confirm that fluorination increases hydrophobicity and boosts DC flashover voltage,further enhancing the material’s performance.
基金supported by the National Natural Science Foundation of China(Grant No.52442104)the Application Research Program of Liaoning Province(Grant No.2022JH2/01300219)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.3132024210)the Scientific Research Fund of the Educational Department of Liaoning Province(Nos.LJ212410151013,LJKMZ20220359)。
文摘Wearable bioelectronic devices are rapidly evolving towards miniaturization and multifunctionality,with remarkable features such as flexibility and comfort.However,achieving a sustainable power supply for wearable bioelectronic devices is still a great challenge.Triboelectric nanogenerators(TENGs)provide an efficient solution by converting irregular,low-frequency bioenergy from the human body into electrical energy.Beyond sustainably powering wearable bioelectronics,the harvested electrical energy also carries rich information for human body sensing.In this conversion process,the choice of material plays a crucial role in affecting the output performance of the TENGs.Among various materials,silicone rubber(SR)stands out due to its exceptional plasticity,flexibility,comfortability and other favorable properties.Moreover,with appropriate treatment,SR can achieve extreme functionalities such as high robustness,good stability,self-healing capabilities,rapid response,and more.In this review,recent advances in wearable SR-based TENGs(SR-TENGs)are systematically reviewed with a focus on their application in different parts of the human body.Given that the manufacturing method of SR-TENGs largely determines its output performance and sensitivity,this paper introduces the design of SR-TENGs,including material selection,process modulation,and structure optimization.Additionally,this article discusses the current challenges in the SR-TENG fabrication technology and potential future directions,aiming to promote the effective development of SR-TENGs in biomechanical energy harvesting and self-powered sensing applications.
文摘Laminated elastomeric bearings used in seismic isolation rely on the mechanical properties of their constituent elastomers to ensure effective performance.However,despite their resistance to temperature fluctuations and environmental aggressors,silicone elastomers exhibit relatively low stiffness,limiting their direct applicability in seismic isolation.This study investigates the effect of fumed silica as a reinforcing filler to enhance the mechanical properties of laminated silicone elastomeric bearings.Elastomeric samples were fabricated with varying fumed silica proportions and subjected to Shore A hardness,uniaxial tensile,and lap shear tests to assess the influence of filler content.Additionally,quasi-static tests were conducted on reduced-scale bearing prototypes under combined vertical compression and cyclic horizontal shear to evaluate their seismic isolation performance.The results demonstrate that fumed silica reinforcement significantly increases stiffness,as evidenced by higher Shore A hardness values.However,a trade-off was observed in tensile properties,with reductions in tensile strength and elongation at break.Despite this,the equivalent elastic modulus did not show substantial variation up to large deformations,indicating that stiffness is preserved under most working conditions.Lap shear tests showed that fumed silica improves shear resistance,while quasi-static tests revealed inelastic behavior with small increases in equivalent shear coefficients but no substantial loss in damping ratios.These findings suggest that fumed silica reinforcement enhances silicone elastomers’stiffness and shear resistance while maintaining moderate damping properties,making it a promising approach for improving the mechanical performance of elastomeric bearings in seismic isolation applications.
基金supported by The Guangxi Scholarship Fund of Guangxi Education Department(GED),Guangxi Key Research and Development Project(Grant No.Guike AB24010217)the Major Special Project of Guangxi Science and Technology(GrantNo.Guike AA23062020)+1 种基金the Guangxi Science and Technology Base and Talent Project(Grant No.Guike AD20297016)the Guangxi Minzu University Startup Project for Talent Introduction in 2019(Grant No.2019KJQD11).
文摘In the production process of silicone sealant,mineral oil is used to replace methyl silicone oil plasticizer in silicone sealant to reduce costs and increase efficiency.However,the silicone sealant content in mineral oil is prone to premature aging,which significantly reduces the mechanical properties of the silicone sealant and severely affects its service life.At the same time,there are few reports on the simulation research of the performance of silicone sealant.In this study,three mixed system models of crosslinking silicone sealant/plasticizer are constructed by the molecular dynamics simulationmethod,and the effect of three influencing factors,namely,crosslinking degree of silicone sealant,plasticizer content and external temperature on the mechanical properties of silicone sealant system is analyzed.The results show that at room temperature,the mechanical properties of the silicone sealant system are enhanced with the increase of its crosslinking degree;At a high crosslinking degree,with the increase of plasticizer content,themechanical properties of the silicone sealant system show an overall decreasing trend.When the methyl silicone oil in the range of 20%,themechanical properties of the silicone sealant appeared tobe a small degree of enhancement;As the temperature increases,the doped mineral oil mechanical properties of silicone sealant declined significantly,while doped with methyl silicone oil silicone sealant and doped with double-ended vinyl silicone oil silicone sealant mechanical properties have better heat resistance.It will provide scientific theoretical guidance for improving and predicting the mechanical properties of silicone sealant.
基金supported by the National Natural Science Foundation of China(Grant Nos.52009107 and 11972285)the Youth Innovation Team Project of Shaanxi Provincial Department of Education(Grant No.21JP079).
文摘With the increasing and refined applications of silicone rubber devices in the biomedical field,it is of great significance to accurately describe and predict the mechanical behavior of them under large deformation.This paper finds that after con-sidering the influence of higher-order shear strain on the normal stress,the Poynting effect in ribbed silicone rubber tubes with certain cross-sectional shapes exhibits a new phenomenon―a non-monotonic trend between axial deformation and twist angle.This paper develops a nonlinear finite element program for simulating large deformations of hyperelastic materials,and studies the Poynting effect in ribbed circular tubes of twisted silicone rubber.The results show that in the ribbed circular tubes with a porosity between 12% and 40%(with the number of ribs ranging from 12 to 26),there appears a normal to reverse conversion of the Poynting effect,that is,the axial extension ratio first decreases and then increases during a monotonic loading process,indicating that the influence of higher-order shear strain on normal stress cannot be ignored when the cross-sectional shape is complex.Especially in ribbed circular tubes with about 20% porosity,a substantial change of axial normal strain from−0.035% to 0.035% can be achieved within a twist angle range of 180°.Based on this,the quantitative influence of higher-order shear strain on normal stress is studied.These research results provide a theoretical basis for accurately controlling the axial expansion and contraction of twisted parts and indicate that a normal to reverse conversion of the Poynting effect can be implemented by designing the cross-sectional shape under certain conditions.
基金support from the Beijing Natural Science Foundation(No.JQ23035)。
文摘High-efficient rubber antioxidants for enhanced heat resistance without compromising mechanical properties remain an enormous and long-term challenge for the rubber industry.Herein,we employed the in-situ growth of Ce-doped Co-metal-organic framework(Ce Co-MOF)in dendritic mesoporous organosilica nanoparticles(DMONs@Ce Co-MOF,denoted as DCCM)to prepare a novel antioxidant that exhibit outstanding thermal stability.Dendritic mesoporous organosilica nanoparticles(DMONs)effectively alleviated the incompatibility of Ce Co-MOF in the polymer matrix,and the effective scavenging of free radicals was attributed to the various oxidation states of metal ions in Ce Co-MOF.Surprising,by adding only0.5 phr(parts per hundred of rubber)of DMONs@Ce Co-MOF to silicone rubber,(SR),the retention rate of tensile strength increased from 37.3%to 61.6%after aging 72 h at 250℃,and the retention rate of elongation at break of DCCM/SR1 composites reached 68%,which was 5.43 times of SR.The strategy of anchoring MOFs on the surface of silica also provides a viable method for preparing effective compound functionalized rubber antioxidant.
基金supported by National Natural Science Foundation of China(51991352 and 51874266).
文摘Silicone rubber(SR)exhibits superior breathability and high-temperature resistance.However,SR is prone to degradation under extreme heat or combustion,limiting its effectiveness in mitigating secondary hazards.In this study,phosphate glass powder was used to calcinate zinc borate,lanthanum oxide,and cerium oxide.Methylphenyl polysiloxane was then grafted onto the surface of the glass powder,resulting in the modified pow-ders designated as Methylphenyl polysiloxane-grafted zinc borate-modified phosphate glass powder(GF-ZnBM),Methylphenyl polysiloxane-grafted lanthanum oxide-modified phosphate glass powder(GF-LaM),and Methylphenyl polysiloxane-grafted cerium oxide-modified phosphate glass powder(GF-CeM).The modified powders were sub-sequently incorporated into silicone rubber composites to enhance the ceramicization capability of silicone rubber at high temperatures.Specifically,GF-CeM and GF-LaM significantly increased the limiting oxygen index(LOI)to 33%and reduced the tendency for combustion propagation.Additionally,GF-CeM notably contributed to enhancing ceramicization strength.The presence of cerium oxide helps in the melting of the glass powder and enhances its adhesion to the silicone rubber matrix.SR/ZnB-GF exhibited the lowest activation energy among the tested composites,along with the best protective capability.The inclusion of modified glass powder has a minor impact on the rheological properties,indicating that the composite retains its ability to flow and deform under stress.This confirms that the material remains flexible under normal conditions and forms a ceramic structure when heated,thereby exhibiting self-supporting properties.This study provides a practical methodology for the targeted modification of glass powders,thereby further enhancing the fire safety of silicone-based composites.
基金supported by the National Key Research and Development Program of China(No.2022YFC3702000)the National Natural Science Foundation of China(No.52070169)the Project of Bureau of Science and Technology of Zhoushan,China(No.2022C41013).
文摘Two-phase partitioning bioreactors(TPPBs)have been widely used because they overcome the mass-transfer limitation of hydrophobic volatile organic compounds(VOCs)in waste gas biological treatments.Understanding the mechanisms of mass-transfer enhancement in TPPBs would enable efficient predictions for further industrial applications.In this study,influences of gradually increasing silicone oil ratio on the TPPB was explored,and a 94.35%reduction of the n-hexane partition coefficient was observed with 0.1 vol.%silicone,which increased to 80.7%along with a 40-fold removal efficiency enhancement in the stabilised removal period.The elimination capacity increased from 1.47 to 148.35 g/(m^(3)·h),i.e.a 101-fold increase compared with that of the single-phase reactors,when 10 vol.%(3 Critical Micelle Concentration)silicone oil was added.The significantly promoted partition coefficient was the main reason for the mass transfer enhancement,which covered the negative influences of the decreased total mass-transfer coefficient with increasing silicone oil volume ratio.The gradually rising stirring rate was benefit to the n-hexane removal,which became negative when the dominant resistance shifted from mass transfer to biodegradation.Moreover,a mass-transfer-reaction kinetic model of the TPPB was constructed based on the balance of n-hexane concentration,dissolved oxygen and biomass.Similar to the mechanism,the partition factor was predicted sensitive to the removal performance,and another five sensitive parameters were found simultaneously.This forecasting method enables the optimisation of TPPB performance and provides theoretical support for hydrophobic VOCs degradation.
基金Supported by the Natural Science Foundation of Hebei Province(No.H2023206907).
文摘AIM:To elucidate the manifestations and associated complications observed in patients with intraocular silicone oil(SO)emulsification through multiple imaging modalities.METHODS:This single-center,observational,retrospective study included 116 patients who underwent pars plana vitrectomy(PPV)with SO injection for retinal detachment(RD),followed by subsequent SO removal at the Second Hospital of Hebei Medical University from January 2013 to January 2023.Comprehensive records of ophthalmic examinations utilizing multiple imaging techniques were maintained.RESULTS:The study comprised 56 females and 60 males,with a mean age of 52.75±13.6y.The mean follow-up duration for SO tamponade was 9.04±11.33mo(range:1-84mo).Among the participants,59 patients were diagnosed with SO emulsification,while 57 patients were in the SO unemulsified group.Patients with SO emulsification had a significantly prolonged SO tamponade duration(P<0.01).Multiple imaging techniques revealed notable signs of SO emulsification and its complications,such as 4 cases(3.4%)with posterior corneal SO-like keratic precipitates(KP)observed by anterior segment photography,23 cases(19.8%)exhibiting spherical high-reflection signals in the inter-retina,retinal pigment epithelium,or choroid detected by Spectralis spectral domain optical coherence tomography(SD-OCT),4 cases(3.4%)showing slow movement of emulsified SO droplets within retinal vessels during fluorescein angiography(FFA),plain and enhanced head magnetic resonance imaging(MRI)images of these four patients did not detect emulsified SO in the lateral ventricles,suprasellar cistern,subarachnoid space,third ventricle,fourth ventricle,or other intracranial locations.CONCLUSION:Intraocular emulsified SO can lead to damage in both anterior and posterior segment tissues,encompassing corneal degeneration,cataracts,glaucoma,retinal and choroid inflammation.Objective multiple imaging techniques such as anterior segment photography,SD-OCT,FFA,and MRI offer comprehensive evaluation and diagnosis of SO emulsification and its associated complications.
基金supported by the National Key R&D Program of China(No.2022YFA1005204l)。
文摘Silicone material extrusion(MEX)is widely used for processing liquids and pastes.Owing to the uneven linewidth and elastic extrusion deformation caused by material accumulation,products may exhibit geometric errors and performance defects,leading to a decline in product quality and affecting its service life.This study proposes a process parameter optimization method that considers the mechanical properties of printed specimens and production costs.To improve the quality of silicone printing samples and reduce production costs,three machine learning models,kernel extreme learning machine(KELM),support vector regression(SVR),and random forest(RF),were developed to predict these three factors.Training data were obtained through a complete factorial experiment.A new dataset is obtained using the Euclidean distance method,which assigns the elimination factor.It is trained with Bayesian optimization algorithms for parameter optimization,the new dataset is input into the improved double Gaussian extreme learning machine,and finally obtains the improved KELM model.The results showed improved prediction accuracy over SVR and RF.Furthermore,a multi-objective optimization framework was proposed by combining genetic algorithm technology with the improved KELM model.The effectiveness and reasonableness of the model algorithm were verified by comparing the optimized results with the experimental results.
基金supported by the Key-Area Research and Development Program of Guangdong Province (No.2020B1111380003)the National Natural Science Foundation of China (Nos.42177377 and 31861133003)。
文摘Nano-enabled silicone-rubber articles for feeding or chewing could be a source of metallic nanoparticles(NPs)directly exposed to infants and young children.However,the impact of steam disinfection on release of NPs and the related potential risks to children's health are unknown.Here,we investigated contents and form of Ag and Zn in 57 nano-enabled silicone-rubber baby bottle teats,pacifiers,and teethers of seven countries and examined the impacts of steam disinfection on in vitro bioaccessibility(IVBA)of Ag and Zn in the articles.Nearly 89%articles had a mixture of Ag-and Zn-containing NPs and the teethers had relatively high Ag and Zn contents(up to 501 and 254μg/g,respectively).Steam disinfection caused rubber decomposition into micro(nano)plastics(0.54-15.7μm)and NP release from the interior of bulk rubber and micro-sized plastics,thus enhancing the IVBA of Ag and Zn by up to 5.5 times.The findings provide insights into mechanisms for NP release by steam disinfection.Though oral exposure risk assessment suggested low health concerns on individual metal release,our study points out the need to assess the potential health risks of child co-exposure to metallic NPs and micro(nano)plastics.
基金Supported by the Shanghai Key Clinical Specialty,Shanghai Eye Disease Research Center(No.2022ZZ01003)the Science and Technology Commission of Shanghai(No.20DZ2270800).
文摘AIM:To evaluate the efficacy and safety of silicone oil(SO)as a corneal lubricant to improve visualization during vitrectomy.METHODS:Patients who underwent vitreoretinal surgery were divided into two groups.Group 1 was operated on with initial SO(Oxane 5700)as a corneal lubricant.Group 2 was operated on with initial lactated ringer’s solution(LRS)and then replaced with SO as required.Fundus clarity was scored during the surgery.Fluorescein staining was performed to determine the damage to corneal epithelium.RESULTS:Totally 114 eyes of 114 patients were included.Single SO use maintained a clear cornea and provided excellent visualization of surgical image.In group 1,the fundus clarity was grade 3 in 41/45 eyes and grade 2 in 4/45 eyes.In group 2,corneal edema frequently occurred after initial LRS use.The fundus clarity was grade 3 in 19/69 eyes,2 in 37/69 eyes and 1 in 13/69 eyes(P<0.05).SO was applied in 29 eyes of initial LRS use with subsequent corneal edema,which eliminated the corneal edema in 26 eyes.Corneal fluorescein staining score in group 1 was 0 in 28 eyes,1 in 11 eyes and 2 in 6 eyes,and 40,20 and 9,respectively,in group 2(all P>0.05).CONCLUSION:The use of SO as a corneal lubricant is effective and safe for preserving and improving corneal clarity and providing clear surgical field during vitrectomy.
基金Supported by National Natural Science Foundation of China(No.81700884)Scientific Research Foundation of National Health and Health Commission(No.WKJ-ZJ-2037)+1 种基金Zhejiang Public Welfare Technology Application Project(No.LGF21H120005)Science and Technology Project of Wenzhou(No.Y20190649).
文摘AIM:To evaluate scleral buckling(SB)surgery using a noncontact wide-field viewing system and 23-gauge intraocular illumination for the treatment of rhegmatogenous retinal detachment in silicone oil(SO)-filled eyes.METHODS:Totally 9 patients(9 eyes)with retinal detachment in SO-filled eyes were retrospectively analyzed.All patients underwent non-contact wide-field viewing system-assisted buckling surgery with 23-gauge intraocular illumination.SO was removed at an appropriate time based on recovery.The patients were followed up for at least 3mo after SO removal.Retinal reattachment,complications,visual acuity and intraocular pressure(IOP)before and after surgery were observed.RESULTS:Patients were followed up for a mean of 8.22mo(3-22mo)after SO removal.All patients had retinal reattachment.At the final follow-up,visual acuity showed improvement for 8 patients,and no change for 1 patient.The IOP was high in 3 patients before surgery,but it stabilized after treatment;it was not affected in the other patients.None of the patients had infections,hemorrhage,anterior ischemia,or any other complication.CONCLUSION:This new non-contact wide-field viewing system-assisted SB surgery with 23-gauge intraocular illumination is effective and safe for retinal detachment in SO-filled eyes.
文摘SiO_(2)-particle reinforced silicon rubber composite(SP-RSRC)is a widely utilized material that offers shock absorption protection to various engineering structures in impact environments.This paper presents a comprehensive investigation of the mechanical behavior of SP-RSRC under various strain rates,employing a combination of experimental,theoretical,and numerical analyses.Firstly,quasi-static and dynamic compression tests were performed on SP-RSRC utilizing a universal testing machine and split Hopkinson pressure bar(SHPB)apparatus.Nonlinear stress-strain relationships of SP-RSRC were obtained for strain rates ranging from 1×10^(−3) to 3065 s^(−1).The results indicated that the composite showed evident strain rate sensitivity,along with nonlinearity.Then,a nonlinear visco-hyperelastic constitutive model was developed,consisting of a hyperelastic component utilizing the 3rd-order Ogden energy function and a viscous component employing a rate-dependent relaxation time scheme.The model accurately characterized the dynamic mechanical response of SP-RSRC,effectively mitigating the challenge of calibrating an excessive number of material parameters inherent in conventional viscoelastic models.Furthermore,the simplified rubber material(SRM)model,integrated within the LS-DYNA software,was chosen to depict the mechanical properties of SP-RSRC in numerical simulations.The parameters of the SRM model were further calibrated based on the strain-stress relationships of SP-RSRC,as predicted by the developed nonlinear visco-hyperelastic constitutive model.Finally,an inverse ballistic experiment using a single-stage air gun was conducted for SP-RSRC.Numerical simulations of SHPB experiments and the inverse ballistic experiment were then performed,and the reliability of the calibrated SRM model was verified by comparing the results of experiments and numerical simulations.This study offers a valuable reference for the utilization of SP-RSRC in the realm of impact protection.
