Griseofulvin (GF) is an antifungal drug whose pharmaceutical activity can be improved by reducing particle size. In this study the rapid expansion of supercritical solution (RESS) was employed to micronize GF.Carbon d...Griseofulvin (GF) is an antifungal drug whose pharmaceutical activity can be improved by reducing particle size. In this study the rapid expansion of supercritical solution (RESS) was employed to micronize GF.Carbon dioxide with cosolvent acetone was chosen as a supercritical mixed solvent. The solubility of GF in super-critical CO2 with cosolvent acetone was measured using a dynamic apparatus at pressures between 12 and 32 MPa,temperatures at 313, 323 and 333 K and cosolvent concentration at 1.5, 3.0, 4.5 and 6.0% (by mole). The effect of pre-expansion pressure, extraction temperature, spraying distance, nozzle size and concentration of cosolvent on the precipitated particles was investigated. The results show that the mean particle size of griseofulvin precipitated by RESS was less than 1.2μm. An increase in pre-expansion pressure, extraction temperature, spraying distance and concentration of cosolvent resulted in a decrease in particle size under the operating condition studied. With the decrease of nozzle diameter the particle size reduces. The crystallinity and melting point of the original material and the processed particle by RESS were tested by X-ray diffraction (XRD) and differential scanning calorimetry (DSC).No evident modification in the crystal habit was found under the experimental conditions tested. The morphology of particles precipitated was analyzed bY scanning electron microscopy (SEM).展开更多
The degradation of Azilsartan in the micronization process was studied and a degradation control method was developed. In the micronization process of Azilsartan, two degradation products （DP-1 and DP-2） were detect...The degradation of Azilsartan in the micronization process was studied and a degradation control method was developed. In the micronization process of Azilsartan, two degradation products （DP-1 and DP-2） were detected by HPLC. DP-1 is a known impurity but DP-2 has not been reported before. The structures of the two degradation products were identified by NMR and MS analysis. The formation of DP- 1 and DP-2 can be controlled by changing the micronization process.展开更多
More than 40%of newly discovered drugs have little or no water solubility which presents a serious challenge to the successful development and commercialization of new drugs in the pharmaceutical industry.Additionally...More than 40%of newly discovered drugs have little or no water solubility which presents a serious challenge to the successful development and commercialization of new drugs in the pharmaceutical industry.Additionally,more than 90%of drugs approved since 1995 have poor solubility,poor permeability,or both.Therefore,it may be necessary to increase the dose of a poorly soluble drug to obtain the required efficacy which can lead to more side effects and higher cost to the patient.Performance of drugs can be improved by decreasing the particle size and,at the same time,increasing specific surface area,dissolution rate and the bioavailability of the drug in the human body.The routes of administration are different and listed as 60%for oral,5%for pulmonary,5%for ocular,5%for topical and 25%for injectable,approximately.The injectable drugs are the most interesting ones for nanoization,because smaller particles will increase performance,and will be useful when using micro needles.In a typical manufacturing process of APIs(active pharmaceutical ingredients)top down processes like high pressure homogenization and wet bead milling are used as standard methods to decrease the particle sizes down to a fineness range of 10 to 500 nanometers.展开更多
Curcumin is a hydrophobic polyphenol compound exhibiting a wide range of biological activities such as anti-inflammatory, anti-bacterial, anti-fungal, anti-carcinogenic, anti-human immunodeficiency virus, and antimicr...Curcumin is a hydrophobic polyphenol compound exhibiting a wide range of biological activities such as anti-inflammatory, anti-bacterial, anti-fungal, anti-carcinogenic, anti-human immunodeficiency virus, and antimicrobial activity. In this employed to produce the work, a swirl mixer was micronized curcumin with polyvinylpyrrolidone （PVP） by the supercritical antisolvent process to improve the bioavailability of curcumin. The effects of operating parameters such as curcumin/PVP ratio, feed concentration, temperature, pressure, and CO2 flow rate were investigated. The characterization and solubility of particles were determined by using scanning electron microscopy, Fourier Transform Infrared spectroscopy, and ultra-violet-visible spectroscopy. The result shows that the optimal condition for the production of curcumin/PVP particles is at curcumin/PVP ratio of 1：30, feed concentration of 5 mg·mL^-1, temperature of 40 ℃, pressure of 15 MPa, and CO2 flow rate of 15 mL·min^-1. Moreover, the dissolution of curcumin/PVP particles is faster than that of raw curcumin.展开更多
Single crystallization is an important strategy to resolve intergranular cracks and unnecessary side reactions with electrolytes in layered transition metal oxide cathodes LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811).Due t...Single crystallization is an important strategy to resolve intergranular cracks and unnecessary side reactions with electrolytes in layered transition metal oxide cathodes LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811).Due to the limitations of high-temperature sintering and multi-step calcination,single crystal NMC811 generally shows irregular particles with a size of 2-3μm.However,the prolonged Li-ion diffusion pathway and the stress generated by the uneven de-/intercalation sluggish Li-ion diffusion kinetics,what is more,cause structural damage such as intragranular cracks.A slow Li extraction rate or particle size reduction will ameliorate the structural damage and improve the cycling stability.As the most promising cathodes for next-generation power batteries,NMC811 required fast charge performance and cycle stability.Particle size reduction appears to be the displacement option.Nanonization is an effective strategy to mitigate intragranular cracks of single crystal NMC811.However,the serious aggregation and increased specific surface area become new challenges.In this article,we synthesized monodisperse nanoscale single crystal NMC811 by molten salt method and modified the surface by LiNbO3 coating.The electrochemical performance shows that nanoscale single crystal NMC811 has faster kinetic and higher capacity retention,so the strategy of combining nanonization and surface coating is an alternative way to prepare high specific capacity and cycle stable single crystal NMC811.展开更多
The submicroparticles of β-sitosterol were produced by using an aerosol solvent extraction system （ASES） and characterized by scanning electronic microscope （SEM）, X-ray diffraction （XRD）, and Fourier transform...The submicroparticles of β-sitosterol were produced by using an aerosol solvent extraction system （ASES） and characterized by scanning electronic microscope （SEM）, X-ray diffraction （XRD）, and Fourier transform infrared （FT-IR） analysis. The effects of operational parameters including pressure, temperature, solution concentration, and ratio of flow rate （CO2/solution, r） on particle size （PS）, yield, and morphology were investigated. The results showed that microparticles of β-sitosterol （less than 1000 nm size and larger than 70% yield） could be obtained at 10-15 MPa, 35 50℃, 15 mg·ml^-1, 10/1（r）; β-sitosterol particles were found to occur as three mophologies： flakes, rods, and spheres by varying ratio of flow rate or solution concentration. In contrast, the crystallinity of β-sitosterol decreased, whereas its molecular structure remained almost unchanged after being ASES-treated. Therefore, ASES was an effective method to produce submicroparticles of β-sitosterol.展开更多
The antioxidant activity of chitosan before micronization (BMC, average particle size of 1850 ± 26.3 μm) and after micronization (AMC, average particle size of 1.37 ± 0.2 μm) in grape juice was studied. An...The antioxidant activity of chitosan before micronization (BMC, average particle size of 1850 ± 26.3 μm) and after micronization (AMC, average particle size of 1.37 ± 0.2 μm) in grape juice was studied. Antioxidant activity was determined, including that of DPPH radicals, hydrogen peroxide and superoxide anion radicals, as well as ABTS radicals of BMC or AMC in grape juice. AMC exhibits stronger scavenging activity toward DPPH radicals, superoxide anion radicals and hydrogen peroxide than BMC. At a concentration of 1.0 mg/mL, AMC in grape juice exhibited 90.0%, 97.3% and 88.7% scavenging activities toward DPPH radicals, hydrogen peroxide and superoxide anion radicals, respectively. The TEAC (Trolox Equivalent Antioxidant Capacity) values of AMC (3.94 ± 0.19) greatly exceeded those of BMC (2.21 ± 0.10) in grape juice. The in vitro results in this investigation suggest the possibility that AMC can increase the antioxidant activity in grape juice. However, comprehensive studies must be performed to ascertain the in vivo safety of AMC in experimental animal models.展开更多
The degradation of mechanical properties of overdischarge battery materials manifests as a significant effect on the energy density,safety,and cycle life of the batteries.However,establishing the correlation between d...The degradation of mechanical properties of overdischarge battery materials manifests as a significant effect on the energy density,safety,and cycle life of the batteries.However,establishing the correlation between depth of overdischarge and mechanical properties is still a significant challenge.Studying the correlation between depth of overdischarge and mechanical properties is of great significance to improving the energy density and the ability to resist abuse of the batteries.In this paper,the mechanical properties of the battery materials during the whole process of overdischarge from discharge to complete failure were studied.The effects of depth of overdischarge on the elastic modulus and hardness of the cathode of the battery,the tensile strength and the thermal shrinkage rate of the separator,and the performance of binder were investigated.The precipitation of Cu dendrites on the separator and cathode after dissolution of anode copper foil is a key factor affecting the performance of battery materials.The Cu dendrites attached to the cathode penetrate the separator,causing irreversible damage to the coating and base film of the separator,which leads to a sharp decline in the tensile strength,thermal shrinkage rate and other properties of the separator.In addition,the Cu dendrites wrapping the cathode active particles reduce the adhesion of the active particles binder.Meanwhile,the active particles are damaged,resulting in a significant decrease in the elastic modulus and hardness of the cathode.展开更多
The booming development of DIW technology present an unprecedented prospect in energetic materials field and has attracted great interest due to its relative simplicity and high flexibility of manufacturing.Herein,a n...The booming development of DIW technology present an unprecedented prospect in energetic materials field and has attracted great interest due to its relative simplicity and high flexibility of manufacturing.Herein,a novel CL-20 based explosive ink formulation have been developed successfully for MEMS initiation systems via DIW technology.We designed PVA/GAP into an oil-in-water(O/W)emulsion,in the way that the aqueous solution of PVA as water phase,the ethyl acetate solution of GAP as oil phase,the combination of Tween 80 and SDS as emulsifier,BPS as a curing agent of GAP.The ideal formulation with good shear-thinning rheology properties and clear gel point was prepared using only 10 wt%emulsion.The dual-cured network formed during the curing process made the printed sample have good mechanical properties.The printed samples had satisfactory molding effect without cracks or fractures,the crystal form of CL-20 not changed and the thermal stability have improved.Deposition of explosive inks via DIW in micro-scale grooves had excellent detonation performances,which critical detonation size was 1×0.045 mm,detonation velocity was 7129 m/s and when the corner reaching 150°can still detonated stably.This study may open new avenues for developing binder systems in explosive ink formulations.展开更多
目的基于腹腔镜模拟手术训练缺乏有效的训练系统的问题,本文采用双目视觉系统设计了一种腹腔镜模拟手术三维纠偏系统,以达到将原设定切割路径呈现在程序界面,同时实时显示手术刀尖端切割路径,并实现纠正切割路径。方法在Visual Studio 2...目的基于腹腔镜模拟手术训练缺乏有效的训练系统的问题,本文采用双目视觉系统设计了一种腹腔镜模拟手术三维纠偏系统,以达到将原设定切割路径呈现在程序界面,同时实时显示手术刀尖端切割路径,并实现纠正切割路径。方法在Visual Studio 2010软件平台上对Micron Tracker进行二次开发,调用Micron Tracker函数库进行Marker点的识别,采用拉格朗日拟合算法拟合出原定路径,通过逐一调用器械尖端坐标画出器械尖端走过的轨迹。结果使用纠偏系统的A组志愿者和不使用纠偏系统的B组志愿者之间的偏移量比较得出:A组的25次实验整体X轴和Y轴正负平均偏移量均小于B组的偏移量;A、B两组第1次和第5次实验相比,正负平均偏移量均显著减少(P<0.05),且随着受试者操作次数的增加偏移量呈减小的趋势;对A、B两组的正负偏移量进行方差分析,可得因素(纠偏系统)对实验指标(偏移量)有显著影响(F>F-crit)。结论本研究设计的纠偏系统能有效减少培训者在培训过程中的偏移量及培训时间,提高培训效率。展开更多
The general behavior of micron-particles in the inner domain of porous ceramic vessel was simulated by computational fluid dynamics software in terms of sampling experimental data.The results show that there is an opt...The general behavior of micron-particles in the inner domain of porous ceramic vessel was simulated by computational fluid dynamics software in terms of sampling experimental data.The results show that there is an optimum porosity of 0.32 to get a higher efficiency and lower pressure drop during filtration.According to the results of simulation and experiment,it is evident that lower inlet velocity can maintain lower pressure drop and obtain higher collection efficiency and inlet concentration also has a crucial influence on the collection efficiency.The collection efficiency of equipment increases significantly with the increase of inlet concentration when the inlet concentration is less than 6.3 g/m3,but it gradually tends to be stable in the range of 97.3%-99.7%when the inlet concentration is over this concentration.展开更多
The feasibility of the rapid degradation of hexachlorobenzene （HCB） by micron-size silver （Ag）/iron （Fe） particles was investigated.Ag/Fe particles with different ratios （0,0.05%,0.09%,0.20%,and 0.45%） were pr...The feasibility of the rapid degradation of hexachlorobenzene （HCB） by micron-size silver （Ag）/iron （Fe） particles was investigated.Ag/Fe particles with different ratios （0,0.05%,0.09%,0.20%,and 0.45%） were prepared by electroless silver plating on 300 mesh Fe powder,and were used to degrade HCB at different pH values and temperatures.The dechlorination ability of Fe greatly increased with small Ag addition,whereas too much added Ag would cover the Fe surface and reduce the effective reaction surface,thereby decreasing the extent of dechlorination.The optimal Ag/Fe ratio was 0.09%.Tafel polarization curves showed that HCB was rapidly degraded at neutral or acidic pH,whereas low pH levels severely intensified H2 production,which consumed the reducing electrons needed for the HCB degradation.HCB degradation was more sensitive to temperature than pH.The rate constant of HCB dechlorination was 0.452 min-1 at 85℃,50 times higher than that at 31℃.HCB was degraded in a successive dechlorination pathway,yielding the main products 1,2,4,5-tetrachlorobenzene and 1,2,4-trichlorobenzene within 2 hr.展开更多
Papaya pulp is very perishable and has a short shelf life. Manually sliced papayas were treated with 0%, 0.25%, 0.5%, and 1% chitosan (non-micronized and micronized) aqueous solutions;placed into plastic trays, and ov...Papaya pulp is very perishable and has a short shelf life. Manually sliced papayas were treated with 0%, 0.25%, 0.5%, and 1% chitosan (non-micronized and micronized) aqueous solutions;placed into plastic trays, and over-wrapped with PVDC film and then stored at 4°C. Color, soluble solid content, water loss, and total plate count of samples were evaluated. Chitosan coating had the ability to maintain the lightness of the sliced papayas. The a* values of the micronized chitosan-coated sliced papayas were significantly lower than those of the-coated. The sliced papayas that had been treated with 1% MC had a higher total soluble solid content and lower b* value after four days of storage. Also, the chitosan coating on the sliced papaya effectively retarded water loss and inhibited the growth of microorganisms. The results reveal that applying a chitosan coating effectively maintained the quality attributes and prolonged the shelf life of the sliced papayas.展开更多
In this study,micronized sand is selected as a kind of filler to partially replace cement in cementitious materials. This filler is considered as chemically inert material,which can not react with water or hydration p...In this study,micronized sand is selected as a kind of filler to partially replace cement in cementitious materials. This filler is considered as chemically inert material,which can not react with water or hydration products,but still indirectly influences the hydration in a positive way. In the experimental program,non-evaporable water test was carried out to determine the degree of hydration of cement paste with and without micronized sands. The influence of different finenesses of sand particles,240 m2/kg,400 m2/kg and 1 300 m2/kg,and different curing ages were investigated. The SEM image analysis was used to characterize the morphological changes of microstructure by the presence of the micronized sand during the cement hydration process. Hydration reaction is enhanced by the use of inert micronized sands. The fineness of micronized sands influences the degree of hydration a lot. The fineness factor has been taken into account in the simulation. There is a clear interface area between sand particle and hydration products.展开更多
Micron/nano scale topographic modification has been a significant focus of interest in current titanium(Ti)surface design.However,the influence of micron/nano structured surface on cell or bacterium behavior on the Ti...Micron/nano scale topographic modification has been a significant focus of interest in current titanium(Ti)surface design.However,the influence of micron/nano structured surface on cell or bacterium behavior on the Ti implant has rarely been systematically evaluated.Moreover,except for popular microgrooves,little work has been carried out on the reaction of cells to the bionic structure.In this study,several micro-pillars mimicking cell morphology were prepared on Ti surfaces by lithography and contact printing(ICP)method,and they were further decorated with nanotube arrays by anodization technology.These surface modifications remarkablly increased the surface roughness of pristine Ti surface from 91.17 nm±5.57 nm to be more than 1000 nm,and reduced their water contact angles from 68.3°±0.7°to be 16.9°±2.4°.Then,the effects of these hierarchical micron/nano scale patterns on the behaviors of MG63 osteoblasts,L929 fibroblasts,SCC epithelial cells and P.gingivalis were studied,aiming to evaluate their performance in osseointegration,gingival epithelial sealing and antibacterial ability.Through an innovative scoring strategy,our findings showed that square micro-pillars with 6μm width and 2μm height combined with 85 nm diameter nanotubes was suitable for implant neck design,while square micro-pillars with 3μm width and 3.6μm height combined with 55 nm diameter nanotubes was the best for implant body design.Our study reveals the synergistic effect of the hierarchical micron/nano scale patterns on MG63 osteoblasts,L929 fibroblasts,SCC epithelial cells and P.gingivalis functions.It provides insight into the design of biomedical implant surfaces.展开更多
文摘Griseofulvin (GF) is an antifungal drug whose pharmaceutical activity can be improved by reducing particle size. In this study the rapid expansion of supercritical solution (RESS) was employed to micronize GF.Carbon dioxide with cosolvent acetone was chosen as a supercritical mixed solvent. The solubility of GF in super-critical CO2 with cosolvent acetone was measured using a dynamic apparatus at pressures between 12 and 32 MPa,temperatures at 313, 323 and 333 K and cosolvent concentration at 1.5, 3.0, 4.5 and 6.0% (by mole). The effect of pre-expansion pressure, extraction temperature, spraying distance, nozzle size and concentration of cosolvent on the precipitated particles was investigated. The results show that the mean particle size of griseofulvin precipitated by RESS was less than 1.2μm. An increase in pre-expansion pressure, extraction temperature, spraying distance and concentration of cosolvent resulted in a decrease in particle size under the operating condition studied. With the decrease of nozzle diameter the particle size reduces. The crystallinity and melting point of the original material and the processed particle by RESS were tested by X-ray diffraction (XRD) and differential scanning calorimetry (DSC).No evident modification in the crystal habit was found under the experimental conditions tested. The morphology of particles precipitated was analyzed bY scanning electron microscopy (SEM).
文摘The degradation of Azilsartan in the micronization process was studied and a degradation control method was developed. In the micronization process of Azilsartan, two degradation products （DP-1 and DP-2） were detected by HPLC. DP-1 is a known impurity but DP-2 has not been reported before. The structures of the two degradation products were identified by NMR and MS analysis. The formation of DP- 1 and DP-2 can be controlled by changing the micronization process.
文摘More than 40%of newly discovered drugs have little or no water solubility which presents a serious challenge to the successful development and commercialization of new drugs in the pharmaceutical industry.Additionally,more than 90%of drugs approved since 1995 have poor solubility,poor permeability,or both.Therefore,it may be necessary to increase the dose of a poorly soluble drug to obtain the required efficacy which can lead to more side effects and higher cost to the patient.Performance of drugs can be improved by decreasing the particle size and,at the same time,increasing specific surface area,dissolution rate and the bioavailability of the drug in the human body.The routes of administration are different and listed as 60%for oral,5%for pulmonary,5%for ocular,5%for topical and 25%for injectable,approximately.The injectable drugs are the most interesting ones for nanoization,because smaller particles will increase performance,and will be useful when using micro needles.In a typical manufacturing process of APIs(active pharmaceutical ingredients)top down processes like high pressure homogenization and wet bead milling are used as standard methods to decrease the particle sizes down to a fineness range of 10 to 500 nanometers.
文摘Curcumin is a hydrophobic polyphenol compound exhibiting a wide range of biological activities such as anti-inflammatory, anti-bacterial, anti-fungal, anti-carcinogenic, anti-human immunodeficiency virus, and antimicrobial activity. In this employed to produce the work, a swirl mixer was micronized curcumin with polyvinylpyrrolidone （PVP） by the supercritical antisolvent process to improve the bioavailability of curcumin. The effects of operating parameters such as curcumin/PVP ratio, feed concentration, temperature, pressure, and CO2 flow rate were investigated. The characterization and solubility of particles were determined by using scanning electron microscopy, Fourier Transform Infrared spectroscopy, and ultra-violet-visible spectroscopy. The result shows that the optimal condition for the production of curcumin/PVP particles is at curcumin/PVP ratio of 1：30, feed concentration of 5 mg·mL^-1, temperature of 40 ℃, pressure of 15 MPa, and CO2 flow rate of 15 mL·min^-1. Moreover, the dissolution of curcumin/PVP particles is faster than that of raw curcumin.
基金financially supported by the National Natural Science Foundation of China(Nos.52022088,51971245,51772262,U20A20336,21935009)Natural Science Foundation of Hebei Province(Nos.F2021203097,B2020203037)China Postdoctoral Science Foundation(No.2021M702756)。
文摘Single crystallization is an important strategy to resolve intergranular cracks and unnecessary side reactions with electrolytes in layered transition metal oxide cathodes LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811).Due to the limitations of high-temperature sintering and multi-step calcination,single crystal NMC811 generally shows irregular particles with a size of 2-3μm.However,the prolonged Li-ion diffusion pathway and the stress generated by the uneven de-/intercalation sluggish Li-ion diffusion kinetics,what is more,cause structural damage such as intragranular cracks.A slow Li extraction rate or particle size reduction will ameliorate the structural damage and improve the cycling stability.As the most promising cathodes for next-generation power batteries,NMC811 required fast charge performance and cycle stability.Particle size reduction appears to be the displacement option.Nanonization is an effective strategy to mitigate intragranular cracks of single crystal NMC811.However,the serious aggregation and increased specific surface area become new challenges.In this article,we synthesized monodisperse nanoscale single crystal NMC811 by molten salt method and modified the surface by LiNbO3 coating.The electrochemical performance shows that nanoscale single crystal NMC811 has faster kinetic and higher capacity retention,so the strategy of combining nanonization and surface coating is an alternative way to prepare high specific capacity and cycle stable single crystal NMC811.
基金Supported by Shanghai Special Foundation on Nanomaterials(0243nm305)the National High Technology Research and Development Program of China(2007AA10Z350)
文摘The submicroparticles of β-sitosterol were produced by using an aerosol solvent extraction system （ASES） and characterized by scanning electronic microscope （SEM）, X-ray diffraction （XRD）, and Fourier transform infrared （FT-IR） analysis. The effects of operational parameters including pressure, temperature, solution concentration, and ratio of flow rate （CO2/solution, r） on particle size （PS）, yield, and morphology were investigated. The results showed that microparticles of β-sitosterol （less than 1000 nm size and larger than 70% yield） could be obtained at 10-15 MPa, 35 50℃, 15 mg·ml^-1, 10/1（r）; β-sitosterol particles were found to occur as three mophologies： flakes, rods, and spheres by varying ratio of flow rate or solution concentration. In contrast, the crystallinity of β-sitosterol decreased, whereas its molecular structure remained almost unchanged after being ASES-treated. Therefore, ASES was an effective method to produce submicroparticles of β-sitosterol.
文摘The antioxidant activity of chitosan before micronization (BMC, average particle size of 1850 ± 26.3 μm) and after micronization (AMC, average particle size of 1.37 ± 0.2 μm) in grape juice was studied. Antioxidant activity was determined, including that of DPPH radicals, hydrogen peroxide and superoxide anion radicals, as well as ABTS radicals of BMC or AMC in grape juice. AMC exhibits stronger scavenging activity toward DPPH radicals, superoxide anion radicals and hydrogen peroxide than BMC. At a concentration of 1.0 mg/mL, AMC in grape juice exhibited 90.0%, 97.3% and 88.7% scavenging activities toward DPPH radicals, hydrogen peroxide and superoxide anion radicals, respectively. The TEAC (Trolox Equivalent Antioxidant Capacity) values of AMC (3.94 ± 0.19) greatly exceeded those of BMC (2.21 ± 0.10) in grape juice. The in vitro results in this investigation suggest the possibility that AMC can increase the antioxidant activity in grape juice. However, comprehensive studies must be performed to ascertain the in vivo safety of AMC in experimental animal models.
基金supported by the National Natural Science Foundation of China(92266206,52227810)the Jilin Province Science and Technology Development Plan(YDZJ202101ZYTS129)the Fundamental Research Funds for the Central Universities(2022-JCXK-11)。
文摘The degradation of mechanical properties of overdischarge battery materials manifests as a significant effect on the energy density,safety,and cycle life of the batteries.However,establishing the correlation between depth of overdischarge and mechanical properties is still a significant challenge.Studying the correlation between depth of overdischarge and mechanical properties is of great significance to improving the energy density and the ability to resist abuse of the batteries.In this paper,the mechanical properties of the battery materials during the whole process of overdischarge from discharge to complete failure were studied.The effects of depth of overdischarge on the elastic modulus and hardness of the cathode of the battery,the tensile strength and the thermal shrinkage rate of the separator,and the performance of binder were investigated.The precipitation of Cu dendrites on the separator and cathode after dissolution of anode copper foil is a key factor affecting the performance of battery materials.The Cu dendrites attached to the cathode penetrate the separator,causing irreversible damage to the coating and base film of the separator,which leads to a sharp decline in the tensile strength,thermal shrinkage rate and other properties of the separator.In addition,the Cu dendrites wrapping the cathode active particles reduce the adhesion of the active particles binder.Meanwhile,the active particles are damaged,resulting in a significant decrease in the elastic modulus and hardness of the cathode.
基金This work was supported by the Graduate Education Innovation Project of Shanxi Province(2020SY401)No.55 Research Institute of China North Industries Group Corporation Open Innovation Fund(WDZC2020JJ017).
文摘The booming development of DIW technology present an unprecedented prospect in energetic materials field and has attracted great interest due to its relative simplicity and high flexibility of manufacturing.Herein,a novel CL-20 based explosive ink formulation have been developed successfully for MEMS initiation systems via DIW technology.We designed PVA/GAP into an oil-in-water(O/W)emulsion,in the way that the aqueous solution of PVA as water phase,the ethyl acetate solution of GAP as oil phase,the combination of Tween 80 and SDS as emulsifier,BPS as a curing agent of GAP.The ideal formulation with good shear-thinning rheology properties and clear gel point was prepared using only 10 wt%emulsion.The dual-cured network formed during the curing process made the printed sample have good mechanical properties.The printed samples had satisfactory molding effect without cracks or fractures,the crystal form of CL-20 not changed and the thermal stability have improved.Deposition of explosive inks via DIW in micro-scale grooves had excellent detonation performances,which critical detonation size was 1×0.045 mm,detonation velocity was 7129 m/s and when the corner reaching 150°can still detonated stably.This study may open new avenues for developing binder systems in explosive ink formulations.
文摘目的基于腹腔镜模拟手术训练缺乏有效的训练系统的问题,本文采用双目视觉系统设计了一种腹腔镜模拟手术三维纠偏系统,以达到将原设定切割路径呈现在程序界面,同时实时显示手术刀尖端切割路径,并实现纠正切割路径。方法在Visual Studio 2010软件平台上对Micron Tracker进行二次开发,调用Micron Tracker函数库进行Marker点的识别,采用拉格朗日拟合算法拟合出原定路径,通过逐一调用器械尖端坐标画出器械尖端走过的轨迹。结果使用纠偏系统的A组志愿者和不使用纠偏系统的B组志愿者之间的偏移量比较得出:A组的25次实验整体X轴和Y轴正负平均偏移量均小于B组的偏移量;A、B两组第1次和第5次实验相比,正负平均偏移量均显著减少(P<0.05),且随着受试者操作次数的增加偏移量呈减小的趋势;对A、B两组的正负偏移量进行方差分析,可得因素(纠偏系统)对实验指标(偏移量)有显著影响(F>F-crit)。结论本研究设计的纠偏系统能有效减少培训者在培训过程中的偏移量及培训时间,提高培训效率。
基金Project(50878080)supported by the National Natural Science Foundation of ChinaProject(K0902006-31)supported by the Key Scientific and Technological Special of Changsha City in China
文摘The general behavior of micron-particles in the inner domain of porous ceramic vessel was simulated by computational fluid dynamics software in terms of sampling experimental data.The results show that there is an optimum porosity of 0.32 to get a higher efficiency and lower pressure drop during filtration.According to the results of simulation and experiment,it is evident that lower inlet velocity can maintain lower pressure drop and obtain higher collection efficiency and inlet concentration also has a crucial influence on the collection efficiency.The collection efficiency of equipment increases significantly with the increase of inlet concentration when the inlet concentration is less than 6.3 g/m3,but it gradually tends to be stable in the range of 97.3%-99.7%when the inlet concentration is over this concentration.
基金supported by the National High Technology Research and Development Program(863)of China(No.2009AA064001)
文摘The feasibility of the rapid degradation of hexachlorobenzene （HCB） by micron-size silver （Ag）/iron （Fe） particles was investigated.Ag/Fe particles with different ratios （0,0.05%,0.09%,0.20%,and 0.45%） were prepared by electroless silver plating on 300 mesh Fe powder,and were used to degrade HCB at different pH values and temperatures.The dechlorination ability of Fe greatly increased with small Ag addition,whereas too much added Ag would cover the Fe surface and reduce the effective reaction surface,thereby decreasing the extent of dechlorination.The optimal Ag/Fe ratio was 0.09%.Tafel polarization curves showed that HCB was rapidly degraded at neutral or acidic pH,whereas low pH levels severely intensified H2 production,which consumed the reducing electrons needed for the HCB degradation.HCB degradation was more sensitive to temperature than pH.The rate constant of HCB dechlorination was 0.452 min-1 at 85℃,50 times higher than that at 31℃.HCB was degraded in a successive dechlorination pathway,yielding the main products 1,2,4,5-tetrachlorobenzene and 1,2,4-trichlorobenzene within 2 hr.
文摘Papaya pulp is very perishable and has a short shelf life. Manually sliced papayas were treated with 0%, 0.25%, 0.5%, and 1% chitosan (non-micronized and micronized) aqueous solutions;placed into plastic trays, and over-wrapped with PVDC film and then stored at 4°C. Color, soluble solid content, water loss, and total plate count of samples were evaluated. Chitosan coating had the ability to maintain the lightness of the sliced papayas. The a* values of the micronized chitosan-coated sliced papayas were significantly lower than those of the-coated. The sliced papayas that had been treated with 1% MC had a higher total soluble solid content and lower b* value after four days of storage. Also, the chitosan coating on the sliced papaya effectively retarded water loss and inhibited the growth of microorganisms. The results reveal that applying a chitosan coating effectively maintained the quality attributes and prolonged the shelf life of the sliced papayas.
文摘In this study,micronized sand is selected as a kind of filler to partially replace cement in cementitious materials. This filler is considered as chemically inert material,which can not react with water or hydration products,but still indirectly influences the hydration in a positive way. In the experimental program,non-evaporable water test was carried out to determine the degree of hydration of cement paste with and without micronized sands. The influence of different finenesses of sand particles,240 m2/kg,400 m2/kg and 1 300 m2/kg,and different curing ages were investigated. The SEM image analysis was used to characterize the morphological changes of microstructure by the presence of the micronized sand during the cement hydration process. Hydration reaction is enhanced by the use of inert micronized sands. The fineness of micronized sands influences the degree of hydration a lot. The fineness factor has been taken into account in the simulation. There is a clear interface area between sand particle and hydration products.
基金This work was funded by the National Natural Science Foundation of China(No.81801855)Young Elite Scientist Sponsorship Program by CSA(No.2018QNRC001)+1 种基金Fundamental Research Funds for the Central Universities,Chengguan District Science and Technology Project(No.2018-7-6)Lanzhou University Hospital of Stomatology Research Support Fund.
文摘Micron/nano scale topographic modification has been a significant focus of interest in current titanium(Ti)surface design.However,the influence of micron/nano structured surface on cell or bacterium behavior on the Ti implant has rarely been systematically evaluated.Moreover,except for popular microgrooves,little work has been carried out on the reaction of cells to the bionic structure.In this study,several micro-pillars mimicking cell morphology were prepared on Ti surfaces by lithography and contact printing(ICP)method,and they were further decorated with nanotube arrays by anodization technology.These surface modifications remarkablly increased the surface roughness of pristine Ti surface from 91.17 nm±5.57 nm to be more than 1000 nm,and reduced their water contact angles from 68.3°±0.7°to be 16.9°±2.4°.Then,the effects of these hierarchical micron/nano scale patterns on the behaviors of MG63 osteoblasts,L929 fibroblasts,SCC epithelial cells and P.gingivalis were studied,aiming to evaluate their performance in osseointegration,gingival epithelial sealing and antibacterial ability.Through an innovative scoring strategy,our findings showed that square micro-pillars with 6μm width and 2μm height combined with 85 nm diameter nanotubes was suitable for implant neck design,while square micro-pillars with 3μm width and 3.6μm height combined with 55 nm diameter nanotubes was the best for implant body design.Our study reveals the synergistic effect of the hierarchical micron/nano scale patterns on MG63 osteoblasts,L929 fibroblasts,SCC epithelial cells and P.gingivalis functions.It provides insight into the design of biomedical implant surfaces.
