The conception of epoxy thermosets with both reprocessability and flame retardancy delineates a new horizon in polymer science,offering a material solution that is not only superior in fire safety but is also environm...The conception of epoxy thermosets with both reprocessability and flame retardancy delineates a new horizon in polymer science,offering a material solution that is not only superior in fire safety but is also environment friendly.Herein,a flame-retardant epoxy vitrimer(EV)was prepared using partially bio-based IADPPO(diphenylphosphine oxide itaconic anhydride)and citric acid as curing reagents via a solvent-free process.Their incorporation created covalent adaptable networks(CANs)in the matrix which promote reprocessability and recyclability.The EV exhibits excellent thermal stability with high initial decomposition temperature(T_(- 5wt%)∼308℃)and high glass transition temperature(T_(g)∼107℃),similar to the blank EV(115℃).The flame retardancy,mechanical properties,transesterification-based reprocessability,and flame-retardant mechanism were investigated.The EV containing 3 wt%phosphorus(EV IADPPO 3P)achieved UL-94 V0 classification with a limiting oxygen index(LOI)of 27%,while the virgin sample Blank EV(without phosphorus)burned completely.Additionally,increased flexural strength of 79%was observed for EV IADPPO 3P compared to Blank EV.Furthermore,the flame-retardant EV showed high malleability and reparability that could be thermomechanically reprocessed without sacrificing the thermal,mechanical,and flame-retardant properties.Thus,the newly developed epoxy vitrimer is not only fire-safe but fulfills the sustainability goals of today’s society.展开更多
Renewable 2,5-furandicarboxylic acid-based polyesters are one of the most promising materials for achieving plastic replacement in the age of energy and environmental crisis.However,their properties still cannot compe...Renewable 2,5-furandicarboxylic acid-based polyesters are one of the most promising materials for achieving plastic replacement in the age of energy and environmental crisis.However,their properties still cannot compete with those of petrochemical-based plastics,owing to insufficient molecular and/or microstructure designs.Herein,we utilize the Ti_(3)C_(2)T_(x)-based MXene nanosheets for decorating carbon nanotube(CNT)and obtaining the structurally stable and highly dispersed dendritic heterostructured MXene@CNT,that can act as multi-roles,i.e.,polycondensation catalyst,crystal nucleator,and interface enhancer of polyester.The biobased MXene@CNT/polybutylene furandicarboxylate(PBF)(denoted as MCP)nanocomposites are synthesized by the strategy of“in situ catalytic polymerization and hot-pressing”.Benefiting from the multi-scale interactions(i.e.,covalent bonds,hydrogen bonds,and physical interlocks)in hybrid structure,the MCP presents exceptional mechanical strength(≈101 MPa),stiffness(≈3.1 GPa),toughness(≈130 MJ m^(-3)),and barrier properties(e.g.,O_(2)0.0187 barrer,CO_(2)0.0264 barrer,and H2O 1.57×10^(-14) g cm cm^(-2) s Pa)that are higher than most reported bio-based materials and engineering plastics.Moreover,it also displays satisfactory multifunctionality with high reprocessability(90%strength retention after 5 recycling),UV resistance(blocking 85%UVA rays),and solvent-resistant properties.As a state-of-art high-performance and multifunctional material,the novel bio-based MCP nanocomposite offers a more sustainable alternative to petrochemical-based plastics in packaging and engineering material fields.More importantly,our catalysis-interfacial strengthening integration strategy opens a door for designing and constructing high-performance bio-based polyester materials in future.展开更多
Polyurethane elastomers with covalent adaptable networks(PU-CANs)based on the dynamic urethane bond have attracted remarkable attention owing to their reprocessability,adaptability,and self-healability.However,it is s...Polyurethane elastomers with covalent adaptable networks(PU-CANs)based on the dynamic urethane bond have attracted remarkable attention owing to their reprocessability,adaptability,and self-healability.However,it is still a formidable challenge to achieve excellent dynamics at low temperatures since the urethane bond energy is usually high.Herein,a fluorinated phenolic polyurethane(FPPU)elastomer with CANs based on phenol±carbamate bonds was successfully designed and prepared.Subsequently,the effects of fluorine atoms on the mechanical properties,thermal stability,reprocessability,and self-healability,surface free energy,and hydrophobicity of the prepared elastomers were systematically investigated.The FPPU elastomer showed notch-insensitivity,remarkable self-healable efficiency(98%),low dynamic dissociation temperature(60℃),excellent reprocessability,and low surface energy(62 MJ m^(-2))compared with non-fluorinated counterpart phenolic polyurethane elastomer(APPU).Based on the above-mentioned features,FPPU was selected as an elastic substrate to assemble into a triboelectric nanogenerator(TENG)to harvest energy from natural motion.This TENG exhibited an excellent electrical output performance with a peak open-circuit voltage of 103 V,a peak short-circuit current of 4.7μA and a peak short-circuit charge of 43 nC.In addition,the TENG possessed high selfcleaning and reprocessing efficiency.Furthermore,a stretchable and self-healing composite conductor based on FPPU was fabricated for flexible electronic devices.展开更多
This article comments on the article by Du et al,who conducted a randomized controlled trial aiming at evaluating the effectiveness of a novel spray flushing system in cleaning flexible endoscopes while minimizing dam...This article comments on the article by Du et al,who conducted a randomized controlled trial aiming at evaluating the effectiveness of a novel spray flushing system in cleaning flexible endoscopes while minimizing damage to the working channels.We share our perspective on the importance of improving endoscope reprocessing methods.The findings highlight the spray flushing system's capacity to improve cleaning efficacy while minimizing damage,suggesting that it might be important in enhancing endoscope reprocessing procedures.展开更多
In current spent nuclear fuel reprocessing,the predominant method involves chemical extraction,leveraging the differing distribution ratios of elements to achieve separation and purification.Effective separation of ur...In current spent nuclear fuel reprocessing,the predominant method involves chemical extraction,leveraging the differing distribution ratios of elements to achieve separation and purification.Effective separation of uranium(U),plutonium(Pu),and neptunium(Np) typically relies on redox processes that alter their oxidation states during extraction.Therefore,reductants play a critical role in reprocessing processes.An important shift in the advanced reprocessing process is the use of salt-free reagents in the actinide separation process.In addition,the salt content in the reprocessing stream is often indicative of the overall technological sophistication of the process,and it is critical to reform the reductants used in the main process stream.Salt-free reductants have attracted much attention in recent years for basic and applied research in reprocessing processes because of their advantages such as being easily destroyed,not introducing salts,reacting quickly,simplifying the process,and reducing the amount of waste.This study summarizes emerging salt-free reagents with potential applications in reprocessing,and outlines their kinetic and chemical reaction mechanism properties in reducing Pu(Ⅳ) and Np(Ⅵ).The conclusion discusses the future potential of salt-free reagents in reprocessing.This study summarizes the currently well-studied salt-free reductants and offers recommendations and future research directions in salt-free alternatives.展开更多
An inverse vulcanized polymer,SZIM combining Zn2+-imidazole coordination bonds and polysulfide bonds was synthesized and incorporated into bio-based Eucommia ulmoides gum (EUG) to generate EUG-SZIM-xs.The residual cry...An inverse vulcanized polymer,SZIM combining Zn2+-imidazole coordination bonds and polysulfide bonds was synthesized and incorporated into bio-based Eucommia ulmoides gum (EUG) to generate EUG-SZIM-xs.The residual crystallinity of the EUG matrix synergistically interacted with the dual cross-linking networks to establish reversible deformation domains,providing EUG-SZIM-xs with quick shape memory capability at moderate temperatures.The damping properties were also investigated,and EUG-SZIM-xs displayed high tanδ values (>0.3) when the SZIM dosage was higher than 5.5 phr,which showed a positive correlation with SZIM concentration.Such good damping performance endowed the EUG-SZIM-xs with broadband low-frequency sound absorption.In addition,the dual cross-linking networks endowed the materials with reprocessability under different catalytic systems,and the 1,8-diazobicyclic[5.4.0]undeca-7-ene (DBU)-catalyzed samples exhibited better mechanical properties than EUG-SZIM-xs.展开更多
The advancement in endoscopic technology and techniques has increased its use in the diagnosis and treatment of gastrointestinal diseases.Reprocessing of reusable endoscopes remains a challenge.Inadequate reprocessing...The advancement in endoscopic technology and techniques has increased its use in the diagnosis and treatment of gastrointestinal diseases.Reprocessing of reusable endoscopes remains a challenge.Inadequate reprocessing leads to bacterial contamination of the endoscope,a significant cause of endoscope-related infections.To thoroughly address the complexities of cleaning a flexible endo-scope,various cleaning methods have been devised and tested across different studies.This letter evaluates one such method,spray flushing for flexible gastro-scopes,developed and tested in a randomized controlled trial by Du et al.Based on the post-processing test results for this method,Du et al conclude that there is improved cleaning efficacy and reduced damage compared to manual brush cleaning.The validity and reliability of the results could be further enhanced by carefully considering the study design and a few underlying concepts that contribute to the reprocessing quality of different types of endoscopes.展开更多
BACKGROUND Commonly used cleaning brushes in the reprocessing of flexible endoscopes often cause damage within the working channels.AIM To develop a spray flushing system to achieving effective cleaning of the working...BACKGROUND Commonly used cleaning brushes in the reprocessing of flexible endoscopes often cause damage within the working channels.AIM To develop a spray flushing system to achieving effective cleaning of the working channels while minimizing damage.METHODS This prospective study included 60 used endoscopes and 60 Teflon tubes randomly divided into a control group(n=30)and an experimental group(n=30).The material of Teflon tubes was the same as that of the endoscope working channel.Endoscopes in the control group were manually cleaned using traditional cleaning brushes,while those in the experimental group were cleaned using the newly developed spray flushing system.ATP levels,cleanliness,and microbiological testing of the working channels were measured.Additionally,Teflon tubes in the control group underwent 500 passes with a cleaning brush,while those in the experimental group were subjected to the spray flushing system,and channel damage was evaluated.RESULTS The ATP levels(RLU)in the two groups were 32.5(13-66)and 26(16-40),respectively(P>0.05).Cleanliness scores were 1.5(1-2)and 1(1-2),respectively(P>0.05).Debris was found in 73.3%of the control group,which was significantly higher than 46.7%in the experimental group(P<0.05).Microbiological tests for both groups yielded negative results.Teflon tube damage in the control group was rated at 4(4-5.25),which was significantly higher than in the experimental group 4(3-4)(P<0.01).CONCLUSION The spray flushing system demonstrated superior efficacy in removing debris and resulted in less damage to the endoscope working channels compared with traditional cleaning brushes.展开更多
In this study,a series of hindered urea bond(HUB)containing polyurethane-urea methacrylate prepolymers and a none HUB containing polyurethane methacrylate prepolymer were prepared using isobornyl methacrylate as the r...In this study,a series of hindered urea bond(HUB)containing polyurethane-urea methacrylate prepolymers and a none HUB containing polyurethane methacrylate prepolymer were prepared using isobornyl methacrylate as the reactive diluent via one-pot procedure.The prepolymers were characterized fully by various techniques.Then,their thermosets were fabricated via UV curing in presence of a photo initiator,and their mechanical property and thermal behavior were investigated and compared.Different from the none HUB containing thermoset,the HUB containing thermosets(defined as PUT)could be recycled and reprocessed by hot press under relatively mild conditions with high recovery ratio of mechanical property.Furthermore,zinc oxide(ZnO)nanoparticles were modified with 3-(trimethoxysilyl)propyl methacrylate and the modified ZnO(defined as ZnO-TPM)was dispersed and polymerized into PUT matrix to prepare their nanocomposites.The influence of ZnO-TPM on the mechanical performance of the composites was evaluated,which indicated that the Young’s modulus and tensile strength increased gradually to the maximum values at ZnO-TPM content of 1 wt%and then decreased.The composites also displayed good reprocessability with improved recovery ratio compared to the pure PUT sample.In addition,the composite materials exhibited strong UV absorption capacity,implying their potential application in the circumstance where UV-shielding was required.展开更多
The incorporation of dynamic covalent bonds into thermosets facilitates the reprocessing of polymer networks,thereby meeting the sustainable requirements for polymer recycling.However,the mechanical properties of many...The incorporation of dynamic covalent bonds into thermosets facilitates the reprocessing of polymer networks,thereby meeting the sustainable requirements for polymer recycling.However,the mechanical properties of many materials often decline significantly upon reprocessing due to side reactions caused by harsh processing conditions.In this work,we find that the aromatic dithiocarbamate bond can undergo dissociation under mild conditions without the need for a catalyst,enabling the efficient reprocessing of the corresponding polydithiourethane.As a consequence,the mechanical properties of the polydithiourethane can be largely preserved after reprocessing.The discovery of this dynamic chemistry is anticipated to broaden the potential for material design in dynamic covalent polymer networks.展开更多
Sea surface temperature(SST)is a crucial physical parameter in meteorology and oceanography.This study demonstrates that the influence of earth incidence angle(EIA)on the SST retrieved from the microwave radiation ima...Sea surface temperature(SST)is a crucial physical parameter in meteorology and oceanography.This study demonstrates that the influence of earth incidence angle(EIA)on the SST retrieved from the microwave radiation imager(MWRI)onboard FengYun-3(FY-3)meteorological satellites should not be ignored.Compared with algorithms that do not consider the influence of EIA in the regression,those that integrate the EIA into the regression can enhance the accuracy of SST retrievals.Subsequently,based on the recalibrated Level 1B data from the FY-3/MWRI,a long-term SST dataset was reprocessed by employing the algorithm that integrates the EIA into the regression.The reprocessed SST data,including FY-3B/MWRI SST during 2010-2019,FY-3C/MWRI SST during 2013-2019,and FY-3D/MWRI SST during 2018-2020,were compared with the in-situ SST and the SST dataset from the Operational Sea Surface Temperature and Ice Analysis(OSTIA).The results show that the FY-3/MWRI SST data were consistent with both the in-situ SST and the OSTIA SST dataset.Compared with the Copernicus Climate Change Service V2.0 SST,the absolute deviation of the reprocessed SST,with a quality flag of 50,was less than 1.5℃.The root mean square errors of the FY-3/MWRI orbital,daily,and monthly SSTs,with a quality flag of 50,were approximately 0.82℃,0.69℃,and 0.37℃,respectively.The primary discrepancies between the FY-3/MWRI SST and the OSTIA SST were found mainly in the regions of the western boundary current and the Antarctic Circumpolar Current.Overall,this reprocessed SST product is recommended for El Niño and La Niña events monitoring.展开更多
Aimed at the problem of stochastic routings for reprocessing operations and highly variable processing times,an open queuing network is utilized to model a typical reprocessing system.In the model,each server is subje...Aimed at the problem of stochastic routings for reprocessing operations and highly variable processing times,an open queuing network is utilized to model a typical reprocessing system.In the model,each server is subject to breakdown and has a finite buffer capacity,while repair times,breakdown times and service time follow an exponential distribution.Based on the decomposition principle and the expansion methodology,an approximation analytical algorithm is proposed to calculate the mean reprocessing time,the throughput of each server and other parameters of the processing system.Then an approach to determining the quality of disassembled parts is suggested,on the basis of which the effect of parts quality on the performance of the reprocessing system is investigated.Numerical examples show that there is a negative correlation between quality of parts and their mean reprocessing time.Furthermore,marginal reprocessing time of the parts decrease with the drop in their quality.展开更多
The purpose of this article is to review the evidence regarding transmission of infection during gastrointestinal endoscopy, factors important in endoscope reprocessing and infection control, areas to focus on to impr...The purpose of this article is to review the evidence regarding transmission of infection during gastrointestinal endoscopy, factors important in endoscope reprocessing and infection control, areas to focus on to improve compliance, and recent developments and advances in the field.展开更多
BACKGROUND Patient-ready duodenoscopes were designed with an assumed contamination rate of less than 0.4%;however,it has been reported that 5.4%of clinically used duodenoscopes remain contaminated with viable high-con...BACKGROUND Patient-ready duodenoscopes were designed with an assumed contamination rate of less than 0.4%;however,it has been reported that 5.4%of clinically used duodenoscopes remain contaminated with viable high-concern organisms despite following the manufacturer’s instructions.Visual inspection of working channels has been proposed as a quality control measure for endoscope reprocessing.There are few studies related to this issue.AIM To investigate the types,severity rate,and locations of abnormal visual inspection findings inside patient-ready duodenoscopes and their microbiological significance.METHODS Visual inspections of channels were performed in 19 patient-ready duodenoscopes using the SpyGlass visualization system in two endoscopy units of tertiary care teaching hospitals(Tri-Service General Hospital and National Taiwan University Hospital)in Taiwan.Inspections were recorded and reviewed to evaluate the presence of channel scratches,buckling,stains,debris,and fluids.These findings were used to analyze the relevance of microbiological surveillance.RESULTS Seventy-two abnormal visual inspection findings in the 19 duodenoscopes were found,including scratches(n=10,52.6%),buckling(n=15,78.9%),stains(n=14,73.7%),debris(n=14,73.7%),and fluids(n=6,31.6%).Duodenoscopes>12 mo old had a significantly higher number of abnormal visual inspection findings than those≤12 mo old(46 findings vs 26 findings,P<0.001).Multivariable regression analyses demonstrated that the bending section had a significantly higher risk of being scratched,buckled,and stained,and accumulating debris than the insertion tube.Debris and fluids showed a significant positive correlation with microbiological contamination(P<0.05).There was no significant positive Spearman’s correlation coefficient between negative bacterial cultures and debris,between that and fluids,and the concomitance of debris and fluids.This result demonstrated that the presence of fluid and debris was associated with positive cultures,but not negative cultures.Further multivariate analysis demonstrated that fluids,but not debris,is an independent factor for bacterial culture positivity.CONCLUSION In patient-ready duodenoscopes,scratches,buckling,stains,debris,and fluids inside the working channel are common,which increase the microbiological contamination susceptibility.The SpyGlass visualization system may be recommended to identify suboptimal reprocessing.展开更多
The high rate of relapse among heroin users remains a significant public concern in China. In the present study, we utilized a Motivation-Skill-Desensitization-Mental Energy (MSDE) intervention and evaluated its effec...The high rate of relapse among heroin users remains a significant public concern in China. In the present study, we utilized a Motivation-Skill-Desensitization-Mental Energy (MSDE) intervention and evaluated its effects on abstinence and mental health. Eighty-nine male heroin users in a drug rehabilitation center were enrolled in the study. The participants in the MSDE intervention group (n=46) received MSDE intervention, which included motivational interviewing, coping skills training, eye movement desensitization and reprocessing, and mindfulness-based psychotherapy. The participants in the control group (h=43) received a series of lectures on skills training. A significant increase in Contemplation Ladder score (P<0.001) and decreases in scores on the Obsessive Compulsive Drug Use Scale (P<0.001), Beck Depression Inventory (P<0.001), and Aggression Questionnaire (P=O.O33) were found immediately after intervention. Compared to the control group, the MSDE intervention group reported significantly higher abstinence rates (P=0.027) and retention rates (P<0.001) at follow-up. Overall, the MSDE intervention, which uses a combined strategy for relapse prevention, could be a promising approach for preventing relapse among heroin users in China.展开更多
The electrochemical behaviour of samarium was investigated in LiF-BeF2 system on an inert （Mo） electrode by cyclic voltammetry and chronopotentiometry at 804, 833, 847 and 872 K. Redox process Sm3＋＋e–→Sm2＋ was ...The electrochemical behaviour of samarium was investigated in LiF-BeF2 system on an inert （Mo） electrode by cyclic voltammetry and chronopotentiometry at 804, 833, 847 and 872 K. Redox process Sm3＋＋e–→Sm2＋ was recognized and analysed. Cyclic voltammetry data suggested that at potential sweep rates lower than 0.25 V/s, the reduction was limited by the diffusion of Sm3＋ ions. It was not possible to observe reduction process of Sm2＋＋2e–→Sm0 due to insufficient electrochemical stability of LiF-BeF2. Diffusion coefficients of Sm3＋ ions in LiF-BeF2 were calculated from voltammetric and chronopotentiometric data in the temperature range 804–872 K. Diffusion coefficient values obeyed Arrhenius law. Activation energy was calculated to be 102.5 kJ/mol.展开更多
The dependence of the magnetic properties on the particle size of recycled HDDR Nd-Fe-B powders was investigated,with the aim to assess the reprocessing potential of the end-of-life scrap magnets via spark plasma sint...The dependence of the magnetic properties on the particle size of recycled HDDR Nd-Fe-B powders was investigated,with the aim to assess the reprocessing potential of the end-of-life scrap magnets via spark plasma sintering(SPS).The as received recycled HDDR powder has coercivity(Hci)=830 kA/m and particles in the range from 30 to 700 μm(average 220 μm).After burr milling,the average particle size is reduced to 120 μm and subsequently the Hci of fine(milled) powder was 595 kA/m.Spark plasma sintering was exploited to consolidate the nanograined HDDR powders and limit the abnormal grain coarsening.The optimal SPS-ing of coarse HDDR powder at 750℃for 1 min produces fully dense magnets with Hci=950±100 kA/m which further increases to 1200 kA/m via thermal treatment at 750℃for 15 min.The burr milled fine HDDR powder under similar SPS conditions and after thermal treatment results in Hci=940 kA/m.The fine powder is further sieved down from 630 to less than 50 μm mesh size,to evaluate the possible reduction in Hci in relation to the particle size.The gain in oxygen content doubles for <50 μm sized particles as compared with coarser fractions(>200 μm).The XRD analysis for fractionated powder indicates an increase in Nd2O3 phase peaks in the finer(<100 μm)fractions.Similarly,the Hci reduces from 820 kA/m in the coarse particles(>200 μm) to 460 kA/m in the fine sized particles(<100μm).SPS was done on each HDDR powder fraction under the optimal conditions to measure the variation in Hci and density.The Hci of SPS-ed coarse fraction(>200 μm) is higher than 930 kA/m and it falls abruptly to just 70 kA/m for the fine sized particles(<100 μm).The thermal treatment further improves the Hci to>1000 kA/m only up to 100 μm sized fractions with>90% sintered density.The full densification(>99%) is observed only in the coarse fractions.The loss of coercivity and lack of sinterability in the fine sized particles(<100 μm) are attributed to a very high oxygen content.This implies that during recycling,if good magnetic properties are to be maintained or even increase the HDDR powder particles can be sized down only up to≥100 μm.展开更多
To use fly ash and coal waste effectively, the current technologies for reprocessing and recycling these wastes into eco-building materials were reviewed, such as utilizing fly ash as the component of fly ash cement a...To use fly ash and coal waste effectively, the current technologies for reprocessing and recycling these wastes into eco-building materials were reviewed, such as utilizing fly ash as the component of fly ash cement and low heat cement after the processes of separation, removal of carbon remains and fine comminution, calcining coal waste into kaolin and meta-kaolin with suspension technology, and preparing clinkerless alkali-activated geopolymer materials with fly ash and meta-kaolin.展开更多
Global Positioning System data processing is affected by many non-tectonic factors, including the common-mode errors （CME） in station-position time series. The characteristics and origins of CME are still not clear,...Global Positioning System data processing is affected by many non-tectonic factors, including the common-mode errors （CME） in station-position time series. The characteristics and origins of CME are still not clear, due to uneven distribution of global GPS networks and the lack of reliable data of the position time series. In this work, data from 241 continuous GPS stations were reprocessed in a consistent way and the results were compared with those generated at Jet Propulsion Laboratory （JPL）. Improvements of residual positions were obtained for many low-quality stations, especially those located in Asia and Australia.展开更多
Due to their unique features,such as the inherent safety,simplified fuel cycle,and continuous on-line reprocessing,molten salt reactors(MSRs)are regarded as one of the six reference reactors in the Generation IV Inter...Due to their unique features,such as the inherent safety,simplified fuel cycle,and continuous on-line reprocessing,molten salt reactors(MSRs)are regarded as one of the six reference reactors in the Generation IV International Forum(GEN-IV).Molten chloride salt fast reactors(MCFRs)are a type of MSR.Compared to molten fluoride salt reactors(MFSRs),MCFRs have a higher solubility of heavy metal atoms,a harder neutron spectrum,lower accumulation of fission products(FPs),and better breeding and transmutation performance.Thus,MCFRs have been recognized as a type of MSR with great prospects for future development.However,as the most important feature for MSRs,the effect of different reprocessing modes on MCFRs must be researched in depth.As such,this study investigated the effect of different isotopes,especially FPs,on the neutronic performance of an MCFR,such as its breeding performance.Furthermore,the characteristics of the different reprocessing modes and MCFR rates were analyzed in terms of safety,radioactivity level,neutron economy,and breeding capacity.In the end,a reprocessing method suitable for MCFRs was determined through calculation and analysis,which provides a reference for the further research of MCFRs.展开更多
基金partially supported by the Swiss National Sci-ence Foundation(Grant No.200021L_196923)by funds from the Zürcher Stiftung für Textilforschung(Winterthur,Switzerland)supported by the China Scholarship Council(CSC No.202006260103)。
文摘The conception of epoxy thermosets with both reprocessability and flame retardancy delineates a new horizon in polymer science,offering a material solution that is not only superior in fire safety but is also environment friendly.Herein,a flame-retardant epoxy vitrimer(EV)was prepared using partially bio-based IADPPO(diphenylphosphine oxide itaconic anhydride)and citric acid as curing reagents via a solvent-free process.Their incorporation created covalent adaptable networks(CANs)in the matrix which promote reprocessability and recyclability.The EV exhibits excellent thermal stability with high initial decomposition temperature(T_(- 5wt%)∼308℃)and high glass transition temperature(T_(g)∼107℃),similar to the blank EV(115℃).The flame retardancy,mechanical properties,transesterification-based reprocessability,and flame-retardant mechanism were investigated.The EV containing 3 wt%phosphorus(EV IADPPO 3P)achieved UL-94 V0 classification with a limiting oxygen index(LOI)of 27%,while the virgin sample Blank EV(without phosphorus)burned completely.Additionally,increased flexural strength of 79%was observed for EV IADPPO 3P compared to Blank EV.Furthermore,the flame-retardant EV showed high malleability and reparability that could be thermomechanically reprocessed without sacrificing the thermal,mechanical,and flame-retardant properties.Thus,the newly developed epoxy vitrimer is not only fire-safe but fulfills the sustainability goals of today’s society.
基金financial supports from the National Natural Science Foundation of China(Grant No.NSFC52473104)National Key R&D Program of China(Grant No.2022YFC2104500)+3 种基金Zhejiang Provincial Natural Science Foundation of China(Grant No.Y24B040002)Ningbo 2025 Key Scientific Research Programs(Grant No.2022Z160)the China Postdoctoral Science Foundation(Grant No.2023M733601)the Ningbo Natural Science Foundation(Grant No.2023I333&2023J409).
文摘Renewable 2,5-furandicarboxylic acid-based polyesters are one of the most promising materials for achieving plastic replacement in the age of energy and environmental crisis.However,their properties still cannot compete with those of petrochemical-based plastics,owing to insufficient molecular and/or microstructure designs.Herein,we utilize the Ti_(3)C_(2)T_(x)-based MXene nanosheets for decorating carbon nanotube(CNT)and obtaining the structurally stable and highly dispersed dendritic heterostructured MXene@CNT,that can act as multi-roles,i.e.,polycondensation catalyst,crystal nucleator,and interface enhancer of polyester.The biobased MXene@CNT/polybutylene furandicarboxylate(PBF)(denoted as MCP)nanocomposites are synthesized by the strategy of“in situ catalytic polymerization and hot-pressing”.Benefiting from the multi-scale interactions(i.e.,covalent bonds,hydrogen bonds,and physical interlocks)in hybrid structure,the MCP presents exceptional mechanical strength(≈101 MPa),stiffness(≈3.1 GPa),toughness(≈130 MJ m^(-3)),and barrier properties(e.g.,O_(2)0.0187 barrer,CO_(2)0.0264 barrer,and H2O 1.57×10^(-14) g cm cm^(-2) s Pa)that are higher than most reported bio-based materials and engineering plastics.Moreover,it also displays satisfactory multifunctionality with high reprocessability(90%strength retention after 5 recycling),UV resistance(blocking 85%UVA rays),and solvent-resistant properties.As a state-of-art high-performance and multifunctional material,the novel bio-based MCP nanocomposite offers a more sustainable alternative to petrochemical-based plastics in packaging and engineering material fields.More importantly,our catalysis-interfacial strengthening integration strategy opens a door for designing and constructing high-performance bio-based polyester materials in future.
基金supported by the National Key Research and Development Program of China(2021YFC2101804 and2021YFC2101802)the National Natural Science Foundation of China(52173117,52073049,and 21991123)+9 种基金Shanghai Rising-Star Program(21QA1400200)the Open Research Fund of Center for Civil Aviation Composites of Donghua University and Shanghai Collaborative Innovation Center of High Performance Fibers and Composites(Province-Ministry Joint)the Natural Science Foundation of Shanghai(20ZR1402500 and22ZR1400700)China Postdoctoral Science Foundation(2021M702898)the Belt&Road Young Scientist Exchanges Project of Science and Technology Commission Foundation of Shanghai(20520741000)the Science and Technology Commission of Shanghai(20DZ2254900)Ningbo 2025 Science and Technology Major Project(2019B10068)Jiangsu Agricultural Science and Technology Innovation Fund(CX(20)3140)the Fundamental Research Funds for the Central Universities(2232021G-02)DHU Distinguished Young Professor Program(LZA2019001)。
文摘Polyurethane elastomers with covalent adaptable networks(PU-CANs)based on the dynamic urethane bond have attracted remarkable attention owing to their reprocessability,adaptability,and self-healability.However,it is still a formidable challenge to achieve excellent dynamics at low temperatures since the urethane bond energy is usually high.Herein,a fluorinated phenolic polyurethane(FPPU)elastomer with CANs based on phenol±carbamate bonds was successfully designed and prepared.Subsequently,the effects of fluorine atoms on the mechanical properties,thermal stability,reprocessability,and self-healability,surface free energy,and hydrophobicity of the prepared elastomers were systematically investigated.The FPPU elastomer showed notch-insensitivity,remarkable self-healable efficiency(98%),low dynamic dissociation temperature(60℃),excellent reprocessability,and low surface energy(62 MJ m^(-2))compared with non-fluorinated counterpart phenolic polyurethane elastomer(APPU).Based on the above-mentioned features,FPPU was selected as an elastic substrate to assemble into a triboelectric nanogenerator(TENG)to harvest energy from natural motion.This TENG exhibited an excellent electrical output performance with a peak open-circuit voltage of 103 V,a peak short-circuit current of 4.7μA and a peak short-circuit charge of 43 nC.In addition,the TENG possessed high selfcleaning and reprocessing efficiency.Furthermore,a stretchable and self-healing composite conductor based on FPPU was fabricated for flexible electronic devices.
文摘This article comments on the article by Du et al,who conducted a randomized controlled trial aiming at evaluating the effectiveness of a novel spray flushing system in cleaning flexible endoscopes while minimizing damage to the working channels.We share our perspective on the importance of improving endoscope reprocessing methods.The findings highlight the spray flushing system's capacity to improve cleaning efficacy while minimizing damage,suggesting that it might be important in enhancing endoscope reprocessing procedures.
文摘In current spent nuclear fuel reprocessing,the predominant method involves chemical extraction,leveraging the differing distribution ratios of elements to achieve separation and purification.Effective separation of uranium(U),plutonium(Pu),and neptunium(Np) typically relies on redox processes that alter their oxidation states during extraction.Therefore,reductants play a critical role in reprocessing processes.An important shift in the advanced reprocessing process is the use of salt-free reagents in the actinide separation process.In addition,the salt content in the reprocessing stream is often indicative of the overall technological sophistication of the process,and it is critical to reform the reductants used in the main process stream.Salt-free reductants have attracted much attention in recent years for basic and applied research in reprocessing processes because of their advantages such as being easily destroyed,not introducing salts,reacting quickly,simplifying the process,and reducing the amount of waste.This study summarizes emerging salt-free reagents with potential applications in reprocessing,and outlines their kinetic and chemical reaction mechanism properties in reducing Pu(Ⅳ) and Np(Ⅵ).The conclusion discusses the future potential of salt-free reagents in reprocessing.This study summarizes the currently well-studied salt-free reductants and offers recommendations and future research directions in salt-free alternatives.
基金supported by the Natural Science Foundation of Hunan Province(No.2024JJ7392)the National Natural Science Foundation of China(No.52463002)+1 种基金Educational Commission of Hunan Province(No.22A0383)Special Funds for Construction of Innovative Provinces in Hunan Province(No.2020SK2028).
文摘An inverse vulcanized polymer,SZIM combining Zn2+-imidazole coordination bonds and polysulfide bonds was synthesized and incorporated into bio-based Eucommia ulmoides gum (EUG) to generate EUG-SZIM-xs.The residual crystallinity of the EUG matrix synergistically interacted with the dual cross-linking networks to establish reversible deformation domains,providing EUG-SZIM-xs with quick shape memory capability at moderate temperatures.The damping properties were also investigated,and EUG-SZIM-xs displayed high tanδ values (>0.3) when the SZIM dosage was higher than 5.5 phr,which showed a positive correlation with SZIM concentration.Such good damping performance endowed the EUG-SZIM-xs with broadband low-frequency sound absorption.In addition,the dual cross-linking networks endowed the materials with reprocessability under different catalytic systems,and the 1,8-diazobicyclic[5.4.0]undeca-7-ene (DBU)-catalyzed samples exhibited better mechanical properties than EUG-SZIM-xs.
文摘The advancement in endoscopic technology and techniques has increased its use in the diagnosis and treatment of gastrointestinal diseases.Reprocessing of reusable endoscopes remains a challenge.Inadequate reprocessing leads to bacterial contamination of the endoscope,a significant cause of endoscope-related infections.To thoroughly address the complexities of cleaning a flexible endo-scope,various cleaning methods have been devised and tested across different studies.This letter evaluates one such method,spray flushing for flexible gastro-scopes,developed and tested in a randomized controlled trial by Du et al.Based on the post-processing test results for this method,Du et al conclude that there is improved cleaning efficacy and reduced damage compared to manual brush cleaning.The validity and reliability of the results could be further enhanced by carefully considering the study design and a few underlying concepts that contribute to the reprocessing quality of different types of endoscopes.
基金West China Nursing Discipline Development Special Fund Project,No.HXHL21029。
文摘BACKGROUND Commonly used cleaning brushes in the reprocessing of flexible endoscopes often cause damage within the working channels.AIM To develop a spray flushing system to achieving effective cleaning of the working channels while minimizing damage.METHODS This prospective study included 60 used endoscopes and 60 Teflon tubes randomly divided into a control group(n=30)and an experimental group(n=30).The material of Teflon tubes was the same as that of the endoscope working channel.Endoscopes in the control group were manually cleaned using traditional cleaning brushes,while those in the experimental group were cleaned using the newly developed spray flushing system.ATP levels,cleanliness,and microbiological testing of the working channels were measured.Additionally,Teflon tubes in the control group underwent 500 passes with a cleaning brush,while those in the experimental group were subjected to the spray flushing system,and channel damage was evaluated.RESULTS The ATP levels(RLU)in the two groups were 32.5(13-66)and 26(16-40),respectively(P>0.05).Cleanliness scores were 1.5(1-2)and 1(1-2),respectively(P>0.05).Debris was found in 73.3%of the control group,which was significantly higher than 46.7%in the experimental group(P<0.05).Microbiological tests for both groups yielded negative results.Teflon tube damage in the control group was rated at 4(4-5.25),which was significantly higher than in the experimental group 4(3-4)(P<0.01).CONCLUSION The spray flushing system demonstrated superior efficacy in removing debris and resulted in less damage to the endoscope working channels compared with traditional cleaning brushes.
文摘In this study,a series of hindered urea bond(HUB)containing polyurethane-urea methacrylate prepolymers and a none HUB containing polyurethane methacrylate prepolymer were prepared using isobornyl methacrylate as the reactive diluent via one-pot procedure.The prepolymers were characterized fully by various techniques.Then,their thermosets were fabricated via UV curing in presence of a photo initiator,and their mechanical property and thermal behavior were investigated and compared.Different from the none HUB containing thermoset,the HUB containing thermosets(defined as PUT)could be recycled and reprocessed by hot press under relatively mild conditions with high recovery ratio of mechanical property.Furthermore,zinc oxide(ZnO)nanoparticles were modified with 3-(trimethoxysilyl)propyl methacrylate and the modified ZnO(defined as ZnO-TPM)was dispersed and polymerized into PUT matrix to prepare their nanocomposites.The influence of ZnO-TPM on the mechanical performance of the composites was evaluated,which indicated that the Young’s modulus and tensile strength increased gradually to the maximum values at ZnO-TPM content of 1 wt%and then decreased.The composites also displayed good reprocessability with improved recovery ratio compared to the pure PUT sample.In addition,the composite materials exhibited strong UV absorption capacity,implying their potential application in the circumstance where UV-shielding was required.
基金financially supported by the National Natural Science Foundation of China(Nos.22275162 and 52322307)。
文摘The incorporation of dynamic covalent bonds into thermosets facilitates the reprocessing of polymer networks,thereby meeting the sustainable requirements for polymer recycling.However,the mechanical properties of many materials often decline significantly upon reprocessing due to side reactions caused by harsh processing conditions.In this work,we find that the aromatic dithiocarbamate bond can undergo dissociation under mild conditions without the need for a catalyst,enabling the efficient reprocessing of the corresponding polydithiourethane.As a consequence,the mechanical properties of the polydithiourethane can be largely preserved after reprocessing.The discovery of this dynamic chemistry is anticipated to broaden the potential for material design in dynamic covalent polymer networks.
基金National Natural Science Foundation of China(42330602)Youth Innovation Team for“FengYun Satellite Remote Sensing Product Verification”(CMA2023QN12)。
文摘Sea surface temperature(SST)is a crucial physical parameter in meteorology and oceanography.This study demonstrates that the influence of earth incidence angle(EIA)on the SST retrieved from the microwave radiation imager(MWRI)onboard FengYun-3(FY-3)meteorological satellites should not be ignored.Compared with algorithms that do not consider the influence of EIA in the regression,those that integrate the EIA into the regression can enhance the accuracy of SST retrievals.Subsequently,based on the recalibrated Level 1B data from the FY-3/MWRI,a long-term SST dataset was reprocessed by employing the algorithm that integrates the EIA into the regression.The reprocessed SST data,including FY-3B/MWRI SST during 2010-2019,FY-3C/MWRI SST during 2013-2019,and FY-3D/MWRI SST during 2018-2020,were compared with the in-situ SST and the SST dataset from the Operational Sea Surface Temperature and Ice Analysis(OSTIA).The results show that the FY-3/MWRI SST data were consistent with both the in-situ SST and the OSTIA SST dataset.Compared with the Copernicus Climate Change Service V2.0 SST,the absolute deviation of the reprocessed SST,with a quality flag of 50,was less than 1.5℃.The root mean square errors of the FY-3/MWRI orbital,daily,and monthly SSTs,with a quality flag of 50,were approximately 0.82℃,0.69℃,and 0.37℃,respectively.The primary discrepancies between the FY-3/MWRI SST and the OSTIA SST were found mainly in the regions of the western boundary current and the Antarctic Circumpolar Current.Overall,this reprocessed SST product is recommended for El Niño and La Niña events monitoring.
文摘Aimed at the problem of stochastic routings for reprocessing operations and highly variable processing times,an open queuing network is utilized to model a typical reprocessing system.In the model,each server is subject to breakdown and has a finite buffer capacity,while repair times,breakdown times and service time follow an exponential distribution.Based on the decomposition principle and the expansion methodology,an approximation analytical algorithm is proposed to calculate the mean reprocessing time,the throughput of each server and other parameters of the processing system.Then an approach to determining the quality of disassembled parts is suggested,on the basis of which the effect of parts quality on the performance of the reprocessing system is investigated.Numerical examples show that there is a negative correlation between quality of parts and their mean reprocessing time.Furthermore,marginal reprocessing time of the parts decrease with the drop in their quality.
文摘The purpose of this article is to review the evidence regarding transmission of infection during gastrointestinal endoscopy, factors important in endoscope reprocessing and infection control, areas to focus on to improve compliance, and recent developments and advances in the field.
基金Ministry of Defense-Medical Affairs Bureau,Tri-Service General Hospital,No.TSGH-D-109182.
文摘BACKGROUND Patient-ready duodenoscopes were designed with an assumed contamination rate of less than 0.4%;however,it has been reported that 5.4%of clinically used duodenoscopes remain contaminated with viable high-concern organisms despite following the manufacturer’s instructions.Visual inspection of working channels has been proposed as a quality control measure for endoscope reprocessing.There are few studies related to this issue.AIM To investigate the types,severity rate,and locations of abnormal visual inspection findings inside patient-ready duodenoscopes and their microbiological significance.METHODS Visual inspections of channels were performed in 19 patient-ready duodenoscopes using the SpyGlass visualization system in two endoscopy units of tertiary care teaching hospitals(Tri-Service General Hospital and National Taiwan University Hospital)in Taiwan.Inspections were recorded and reviewed to evaluate the presence of channel scratches,buckling,stains,debris,and fluids.These findings were used to analyze the relevance of microbiological surveillance.RESULTS Seventy-two abnormal visual inspection findings in the 19 duodenoscopes were found,including scratches(n=10,52.6%),buckling(n=15,78.9%),stains(n=14,73.7%),debris(n=14,73.7%),and fluids(n=6,31.6%).Duodenoscopes>12 mo old had a significantly higher number of abnormal visual inspection findings than those≤12 mo old(46 findings vs 26 findings,P<0.001).Multivariable regression analyses demonstrated that the bending section had a significantly higher risk of being scratched,buckled,and stained,and accumulating debris than the insertion tube.Debris and fluids showed a significant positive correlation with microbiological contamination(P<0.05).There was no significant positive Spearman’s correlation coefficient between negative bacterial cultures and debris,between that and fluids,and the concomitance of debris and fluids.This result demonstrated that the presence of fluid and debris was associated with positive cultures,but not negative cultures.Further multivariate analysis demonstrated that fluids,but not debris,is an independent factor for bacterial culture positivity.CONCLUSION In patient-ready duodenoscopes,scratches,buckling,stains,debris,and fluids inside the working channel are common,which increase the microbiological contamination susceptibility.The SpyGlass visualization system may be recommended to identify suboptimal reprocessing.
基金This study was funded by the National Natural Science Foundation of China (No.30872175,No.81573236).
文摘The high rate of relapse among heroin users remains a significant public concern in China. In the present study, we utilized a Motivation-Skill-Desensitization-Mental Energy (MSDE) intervention and evaluated its effects on abstinence and mental health. Eighty-nine male heroin users in a drug rehabilitation center were enrolled in the study. The participants in the MSDE intervention group (n=46) received MSDE intervention, which included motivational interviewing, coping skills training, eye movement desensitization and reprocessing, and mindfulness-based psychotherapy. The participants in the control group (h=43) received a series of lectures on skills training. A significant increase in Contemplation Ladder score (P<0.001) and decreases in scores on the Obsessive Compulsive Drug Use Scale (P<0.001), Beck Depression Inventory (P<0.001), and Aggression Questionnaire (P=O.O33) were found immediately after intervention. Compared to the control group, the MSDE intervention group reported significantly higher abstinence rates (P=0.027) and retention rates (P<0.001) at follow-up. Overall, the MSDE intervention, which uses a combined strategy for relapse prevention, could be a promising approach for preventing relapse among heroin users in China.
基金Project supported by Ministry of Industry and Trade of the Czech Republic
文摘The electrochemical behaviour of samarium was investigated in LiF-BeF2 system on an inert （Mo） electrode by cyclic voltammetry and chronopotentiometry at 804, 833, 847 and 872 K. Redox process Sm3＋＋e–→Sm2＋ was recognized and analysed. Cyclic voltammetry data suggested that at potential sweep rates lower than 0.25 V/s, the reduction was limited by the diffusion of Sm3＋ ions. It was not possible to observe reduction process of Sm2＋＋2e–→Sm0 due to insufficient electrochemical stability of LiF-BeF2. Diffusion coefficients of Sm3＋ ions in LiF-BeF2 were calculated from voltammetric and chronopotentiometric data in the temperature range 804–872 K. Diffusion coefficient values obeyed Arrhenius law. Activation energy was calculated to be 102.5 kJ/mol.
基金Project supported by European Community’s Horizon 2020Program [H2020/2014-2019] under grant Agreement No.674973(MSCA-ETN DEMETER)
文摘The dependence of the magnetic properties on the particle size of recycled HDDR Nd-Fe-B powders was investigated,with the aim to assess the reprocessing potential of the end-of-life scrap magnets via spark plasma sintering(SPS).The as received recycled HDDR powder has coercivity(Hci)=830 kA/m and particles in the range from 30 to 700 μm(average 220 μm).After burr milling,the average particle size is reduced to 120 μm and subsequently the Hci of fine(milled) powder was 595 kA/m.Spark plasma sintering was exploited to consolidate the nanograined HDDR powders and limit the abnormal grain coarsening.The optimal SPS-ing of coarse HDDR powder at 750℃for 1 min produces fully dense magnets with Hci=950±100 kA/m which further increases to 1200 kA/m via thermal treatment at 750℃for 15 min.The burr milled fine HDDR powder under similar SPS conditions and after thermal treatment results in Hci=940 kA/m.The fine powder is further sieved down from 630 to less than 50 μm mesh size,to evaluate the possible reduction in Hci in relation to the particle size.The gain in oxygen content doubles for <50 μm sized particles as compared with coarser fractions(>200 μm).The XRD analysis for fractionated powder indicates an increase in Nd2O3 phase peaks in the finer(<100 μm)fractions.Similarly,the Hci reduces from 820 kA/m in the coarse particles(>200 μm) to 460 kA/m in the fine sized particles(<100μm).SPS was done on each HDDR powder fraction under the optimal conditions to measure the variation in Hci and density.The Hci of SPS-ed coarse fraction(>200 μm) is higher than 930 kA/m and it falls abruptly to just 70 kA/m for the fine sized particles(<100 μm).The thermal treatment further improves the Hci to>1000 kA/m only up to 100 μm sized fractions with>90% sintered density.The full densification(>99%) is observed only in the coarse fractions.The loss of coercivity and lack of sinterability in the fine sized particles(<100 μm) are attributed to a very high oxygen content.This implies that during recycling,if good magnetic properties are to be maintained or even increase the HDDR powder particles can be sized down only up to≥100 μm.
基金Funded by the Sciences and Technology Bureau of Yulin City (No. 2006YL100-06)
文摘To use fly ash and coal waste effectively, the current technologies for reprocessing and recycling these wastes into eco-building materials were reviewed, such as utilizing fly ash as the component of fly ash cement and low heat cement after the processes of separation, removal of carbon remains and fine comminution, calcining coal waste into kaolin and meta-kaolin with suspension technology, and preparing clinkerless alkali-activated geopolymer materials with fly ash and meta-kaolin.
基金supported by the Institute of Crustal Dynamics Fund(ZDJ2009-01)National Natural Science Foundation of China(41104001)
文摘Global Positioning System data processing is affected by many non-tectonic factors, including the common-mode errors （CME） in station-position time series. The characteristics and origins of CME are still not clear, due to uneven distribution of global GPS networks and the lack of reliable data of the position time series. In this work, data from 241 continuous GPS stations were reprocessed in a consistent way and the results were compared with those generated at Jet Propulsion Laboratory （JPL）. Improvements of residual positions were obtained for many low-quality stations, especially those located in Asia and Australia.
基金supported by the Chinese TMSR Strategic Pioneer Science and Technology Project (No.XDA02010000)the Frontier Science Key Program of Chinese Academy of Sciences (No.QYZDY-SSW-JSC016)the Shanghai Sailing Program (No.20YF1457600).
文摘Due to their unique features,such as the inherent safety,simplified fuel cycle,and continuous on-line reprocessing,molten salt reactors(MSRs)are regarded as one of the six reference reactors in the Generation IV International Forum(GEN-IV).Molten chloride salt fast reactors(MCFRs)are a type of MSR.Compared to molten fluoride salt reactors(MFSRs),MCFRs have a higher solubility of heavy metal atoms,a harder neutron spectrum,lower accumulation of fission products(FPs),and better breeding and transmutation performance.Thus,MCFRs have been recognized as a type of MSR with great prospects for future development.However,as the most important feature for MSRs,the effect of different reprocessing modes on MCFRs must be researched in depth.As such,this study investigated the effect of different isotopes,especially FPs,on the neutronic performance of an MCFR,such as its breeding performance.Furthermore,the characteristics of the different reprocessing modes and MCFR rates were analyzed in terms of safety,radioactivity level,neutron economy,and breeding capacity.In the end,a reprocessing method suitable for MCFRs was determined through calculation and analysis,which provides a reference for the further research of MCFRs.
