With ideal combination of benefits that selectively converts high photon energy spectrum into electricity while transmitting low energy photo ns for photos yn thesis,the CH3NH3PbBr3 perovskite solar cell(BPSC)is a pro...With ideal combination of benefits that selectively converts high photon energy spectrum into electricity while transmitting low energy photo ns for photos yn thesis,the CH3NH3PbBr3 perovskite solar cell(BPSC)is a promising candidate for efficient greenhouse based building integrated photovoltaic(BIPV)applications.However,the efficiency of BPSCs is still much lower than their theoretical efficiency.In general,interface band alignment is regarded as the vital factor of the BPSCs whereas only few reports on enhancing perovskite film quality.In this work,highly efficient BPSCs were fabricated by improving the crystallization process of CH3NH3PbBr3 with the assistance of anti-solvents.A new anti-solvent of diphenyl ether(DPE)was developed for its strong interaction with the solvents in the perovskite precursor solution.By using the anti-solvent of DPE,trap-state density of the CH3NH3PbBr3 film is reduced and the electron lifetime is enhanced along with the large-grain crystals compared with the samples from conventional anti-solvent of chlorobenzene.Upon preliminary optimization,the efficiencies of typical and semitransparent BPSCs are improved to as high as 9.54%and 7.51%,respectively.Optical absorption measurement demonstrates that the cell without metal electrode shows 80%transparency in the wavelength range of 550-1000 nm that is perfect for greenhouse vegetation.Considering that the cell absorbs light in the blue spectrum before 550 nm,it offers very high solar cell efficiency with only 17.8%of total photons,while over 60%of total photons can transm让through for photosynthesis if a transparent electrode can be obtained such as indium doped SnO2.展开更多
Many of the physical and functional properties of RDX and HMX explosives are related to the crystalline structure of these materials. Crystalline defects affect the quality of the explosives. Therefore, in order to en...Many of the physical and functional properties of RDX and HMX explosives are related to the crystalline structure of these materials. Crystalline defects affect the quality of the explosives. Therefore, in order to enhance the quality of these materials, it is necessary to form crystals with the lowest defects. In this research, we report the optimization of recrystallization process of RDX and HMX by statistical techniques. The solvent/anti-solvent procedure was used for recrystallization of HMX and RDX particles. The four parameters of i) ratio of anti-solvent to solvent, ii) ratio of solute to solvent, iii) aging time, and iv)cooling rate of mixture, were optimized by Taguchi analysis design. Taguchi L16 orthogonal array was used with sixteen rows corresponding to the number of tests in four columns at four levels. The apparent density of recrystallized of RDX and HMX particles was considered as the quality characteristic with the concept of "the larger-the-better". The obtained graphs showed that the studied parameters were optimized in ratio 1:1 for anti-solvent to solvent, ratio 0.1 g,m L^(-1) for solute to solvent, aging time of 2 h and cooling rate of 1℃,min^(-1). Also, the correlation between the investigated parameters and apparent density of crystals were studied by multiple linear regressions(MLR) method for obtaining a model of prediction of apparent density. The P-values were indicated that in confidence level of 95%, the null hypothesis is rejected and a meaningful addition is observed in the proposed model.展开更多
The objective of the present study was to alter the crystal habit of itraconazole(ITZ)by cooling and anti-solvent crystallization and characterize its properties.ITZ was recrystallized in different solvents and the ef...The objective of the present study was to alter the crystal habit of itraconazole(ITZ)by cooling and anti-solvent crystallization and characterize its properties.ITZ was recrystallized in different solvents and the effects of each solvent on morphology of crystals,dissolution behavior and solid state of recrystallized drug particles were investigated.The results revealed that ITZ crystals recrystallized by cooling and anti-solvent crystallization showed the different crystal habits from the untreated ITZ.Using cooling crystallization tended to provide needle-shaped crystals while the crystals obtained from anti-solvent crystallization showed more flaky,plate shape.This indicated the importance of preparation method on nucleation and crystal growth.No change in drug polymorphism was observed,according to determination of thermal property and crystalline state by differential scanning calorimetry and powder X-ray diffractometry,respectively.The recrystallized ITZ showed higher drug dissolution than untreated ITZ and the highest drug dissolution was observed from the samples recrystallized in the presence of PEG 200,which provided the small plate-shaped crystals with tremendously increased in surface area.However,the increasing of drug dissolution is relatively small,therefore,further development may be required.展开更多
The unfavorable growth and agglomeration of micro-particles of RDX explosive was almost observed in manufacture process. For preventing of growth of micro-particles and agglomeration in anti-solvent crystallization pr...The unfavorable growth and agglomeration of micro-particles of RDX explosive was almost observed in manufacture process. For preventing of growth of micro-particles and agglomeration in anti-solvent crystallization process, the effect of additives glucose, sucrose and poly ethylene glycol-2000 and wetting solvent of isopropyl alcohol were studied. Taguchi experimental design was used for optimization of the operating conditions. The type of additive, the amount of additive(%wt.), solvent of wetting and wetting time were selected for optimization of the conditions. By using 4 factor and 3 levels, 27 experiments were conducted(L27). Results showed that in the presence of 2 %wt. of sucrose additive and isopropyl alcohol solvent, the agglomerations of particles were decreased so that a decrease 30-50% in the average of particles size was seen. Addition additives were effective in storage container and for reduce the agglomeration of particles during storage. Also, the agglomeration rate of particles was reduced over time at optimized conditions. Imaging optical microscopy, scanning electron microscopy(SEM), and particle size analyzer(PSA) methods were used for particles size analyzing as a response in statistical optimization and quality control of the final product. The sensitivity to some mechanical and shock stimuli on the RDX in presence of sucrose additive was tested and the obtained results showed the insignificant effect of additive on the safety properties of pure RDX.展开更多
Self-made enriched 10 B boric acid as raw material was purified by recrystallization. The effects of final crystallization temperature, crystallization time, stirring speed, crystallization frequency and other factors...Self-made enriched 10 B boric acid as raw material was purified by recrystallization. The effects of final crystallization temperature, crystallization time, stirring speed, crystallization frequency and other factors on the purity were investigated. The appropriate operating condition was that the final crystallization temperature and time were 5,℃ and 10 h respectively under a low-speed stirring for crystallizing twice, which would make the purity and yield of boric acid reach 99.94% and 95.36%, respectively. Taking this as foundation, recrystallization process was optimized with acetone as anti-solvent, whose amount was the most important index. The boric acid solution was added into acetone and recrystallized under the same condition, and the purity and yield of boric acid would reach 99.98% and 99.61%, respectively. The product detected by XRD was confirmed as boric acid crystal. Main ion concentration in the product was detected by ICP, which basically met the national standard of high purity. Crystal morphology of boric acid was observed by SEM.展开更多
In explosive research area, one of important trends is to study on the preparation technology of explosive microparticles. A new principle and method based on supercritical anti-solvent (SAS) process is put forward an...In explosive research area, one of important trends is to study on the preparation technology of explosive microparticles. A new principle and method based on supercritical anti-solvent (SAS) process is put forward and discussed for the preparation of explosive micro-particles. The satisfactory micro-particles of explosives can be obtained easily by its particular mechanism of creating micro-particles, and operating conditions at normal temperature. This method is good for further study and development.展开更多
CeO2-ZrO2-Al2O3 ternary oxides were successfully prepared by a green route of supercritical anti-solvent precipitation with supercritical CO2 as anti-solvent and methanol as solvent. The structures and oxygen storage ...CeO2-ZrO2-Al2O3 ternary oxides were successfully prepared by a green route of supercritical anti-solvent precipitation with supercritical CO2 as anti-solvent and methanol as solvent. The structures and oxygen storage capacities of these ternary oxides were characterized by XRD, Raman spectra and oxygen storage capacity measurements. It was found that Al3＋ and Zr4＋ inserted into CeO2 lattice, forming CeO2-ZrO2-Al2O3 solid solution. The concentration of aluminium isopropoxide in the solution affected the concentration of oxygen vacancy and the distortion of oxygen sublattice which were responsible for the oxygen storage capacity. The rapidest oxygen uptake/release rate and maximum total oxygen storage capacity （122.0 mmolO2/molCeO2） were obtained with the aluminitun isopropoxide concentration at 0.2 wt.% in the solution.展开更多
To improve the physicochemical properties of astaxanthin, it was encapsulated in poly (1-lactic acid)(PLLA) using a supercritical anti-solvent (SAS) process with dichloromethane/acetone mixture as the solvent, and sup...To improve the physicochemical properties of astaxanthin, it was encapsulated in poly (1-lactic acid)(PLLA) using a supercritical anti-solvent (SAS) process with dichloromethane/acetone mixture as the solvent, and supercritical CO2 as the anti-solvent. The effects of altering five SAS operating cond让ions, solvent ratio, temperature, pressure, concentration of carrier, and flow rate, on the microstructure of particles were investigated using an orthogonal experimental design. Under the optimal conditions, astaxanthin/PLLA particles were produced with an encapsulation efficiency of 91.5% and a mean particle size of 954.6 nm. SEM images showed that most astaxanthin/PLLA particles were uniform microspheres. FT-IR spectra showed that the chemical structure of astaxanthin was unchanged by the SAS process. The results of chromatic difference, X-ray diffraction, thermogravimetric, and differential scanning calorimetry analyses showed that astaxanthin had been encapsulated in the PLLA matrix in an amorphous state. Overall, astaxanthin/PLLA microspheres greatly enhanced the stability of astaxanthin during storage, and the levels of residual solvents were far lower than the ICH lim让s. This means that astaxanthin/PLLA microspheres prepared using SAS show great potential for use in many food, cosmetic, and pharmaceutical formulations.展开更多
An efficient solution-processable route employing Pb(Ac)2 as lead source and anti-solvent treatment to achieve fully covered and homogenous perovskite films is reported. The effect of different solution methods and de...An efficient solution-processable route employing Pb(Ac)2 as lead source and anti-solvent treatment to achieve fully covered and homogenous perovskite films is reported. The effect of different solution methods and device architectures on the morphologies of perovskite films were systematically investigated. Our results show that the planar perovskite layer fabricated by one-step solution method achieved fully covered and pinhole-free films. Further anti-solvent treatment using chlorobenzene (CB) promoted a perovskite film with highly smooth surfaces and enlarged grain sizes. Device fabricated from CB treated perovskite film achieved a best PCE of 15.80%, in comparison with 14.02%for the untreated device. These results evidently suggest a feasible route towards controlling the crystallization and morphology of planar heterojunction (PHJ) PSCs for improved efficiency.展开更多
The nano-crystalline Cu-Ce-Zr-O composite oxides were successfully prepared by the supercritical anti-solvent （SAS） process. The physicochemical properties and catalytic performances were investigated by X-ray diffr...The nano-crystalline Cu-Ce-Zr-O composite oxides were successfully prepared by the supercritical anti-solvent （SAS） process. The physicochemical properties and catalytic performances were investigated by X-ray diffraction （XRD）, Raman spectroscopy, H2 temperature-programmed reduction （H2 -TPR）, oxygen storage capacity （OSC） measurement and catalytic activity evaluation. It was found that Cu2＋ ions incorporated into CeO2 -ZrO2 lattice to form Cu-Ce-Zr-O solid solution associated with the formation of oxygen vacancies. The Cu-Ce-Zr-O catalysts prepared via the SAS process with the Cu content 2.63 mol.% showed the highest OSC index of 636.9 μmol/g. Compared with the samples prepared by impregnation method, Cu doping using SAS process could improve the dispersion of Cu2＋ in the composite oxide, enhance the interaction between Cu2＋ and CeO2-ZrO2 , improve the reducibility of catalyst, and thus improve the OSC performance and increase the catalytic activity for CO oxidation at low temperature.展开更多
In the present work, anti-solvent crystallization of artemisinin from four different organic solvents （methanol, ethanol, acetonitrile, and acetone） was studied. Water was used as anti-solvent. The effect of an impu...In the present work, anti-solvent crystallization of artemisinin from four different organic solvents （methanol, ethanol, acetonitrile, and acetone） was studied. Water was used as anti-solvent. The effect of an impurity （quercetin） on the performance of anti-solvent crystallization of artemisinin was investigated. The fundamental process data such as solubility of artemisinin in pure organic solvents and their binary mixtures with varying composition water were measured at room temperature. The solubility of quercetin was measured only in pure organic solvents at room temperature. Anti-solvent crystallization experiments were designed based on the fundamental process data determined. Firstly, the anti-solvent crystallization of artemisinin without impurity was performed from all four organic solvents and then the experiments were repeated with addition of an impurity （quercetin） while keeping all other process parameters constant. Two different concentrations of impurity, i.e., 10% and 50% of its solubility, in the respective organic solvents at room temperature were used. The effect of impurity on performance of anti-solvent crystallization was evaluated by comparing the yield and purity of the artemisinin obtained with those in the absence of impurity. Results of the present work demonstrated that the presence of quercetin in the solution does not affect the final yield of artemisinin from the solution of each of four organic solvents used. However, the purity of artemisinin crystals were reduced when quercetin concentration was 50% of its solubility in all solvents studied.展开更多
Hollow CuO-CeO2-ZrO2nano-particles were prepared with supercritical anti-solvent apparatus by using methanol as sol-vent and supercritical carbon dioxide as anti-solvent. Two key factors （i.e., pressure and temperat...Hollow CuO-CeO2-ZrO2nano-particles were prepared with supercritical anti-solvent apparatus by using methanol as sol-vent and supercritical carbon dioxide as anti-solvent. Two key factors （i.e., pressure and temperature） were investigated to explore the effects of catalyst structure and physic-chemical properties （i.e., morphology, reducing property, oxygen storage capacity and specific surface area）. The resulting materials were characterized with X-ray diffraction （XRD）, high resolution transmission electron micros-copy （HRTEM）, Brunauer-Emmett-Teller （BET）,hydrogen temperature programmed reduction （H2-TPR） and oxygen storage capac-ity （OSC） measurement, respectively. The experimental results showed that lower temperatures promoted production of hollow struc-ture nano-particulates. The particle morphology also changed significantly, i.e. the solid construction was first transferred to hollow structure then back to solid construction. The optimal conditions for obtaining hollow nano-particles were determined at 45 °C, 18.0–24.0 MPa.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
The interface is crucial for perovskite solar cells(PSCs).However,voids at interfaces induced by the trapped hygroscopic dimethyl sulfoxide(DMSO)can reduce charge extraction and accelerate the film degradation,serious...The interface is crucial for perovskite solar cells(PSCs).However,voids at interfaces induced by the trapped hygroscopic dimethyl sulfoxide(DMSO)can reduce charge extraction and accelerate the film degradation,seriously damaging the efficiency and stability.In this work,4,4’-dinonyl-2,2’-dipyridine(DN-DP),a Lewis base with long alkyl chains is introduced to solve this problem.Theoretical calculated and experimental results confirm that the dipyridyl group on DN-DP can more strongly coordinate with Pb^(2+)than that of the S=O group on DMSO.The strong coordination effect plays a crucial role in removing the DMSO-based adduct and reducing the formation of voids.Due to the electron-donating properties of pyridine,the existence of DN-DP in the perovskite film can passivate the defects and optimize the energy level alignment of the perovskite configuration.The open-circuit voltage(VOC)of the DN-DP-based PSC is improved from 1.107 V(control device)to 1.153 V,giving rise to a power conversion efficiency(PCE)of24.02%.Furthermore,benefiting from the moisture resistance stemming from the hydrophobic nonyl group,the PCE retains 90.4%of the initial performance after 1000 h of storage in the ambient condition.展开更多
基金supported by the National Key Research Program of China (2016YFA0202403)National Nature Science Foundation of China (61674098)+1 种基金the 111 Project (B1404)Chinese National 1000-Talent-Plan program (Grant No. 111001034)
文摘With ideal combination of benefits that selectively converts high photon energy spectrum into electricity while transmitting low energy photo ns for photos yn thesis,the CH3NH3PbBr3 perovskite solar cell(BPSC)is a promising candidate for efficient greenhouse based building integrated photovoltaic(BIPV)applications.However,the efficiency of BPSCs is still much lower than their theoretical efficiency.In general,interface band alignment is regarded as the vital factor of the BPSCs whereas only few reports on enhancing perovskite film quality.In this work,highly efficient BPSCs were fabricated by improving the crystallization process of CH3NH3PbBr3 with the assistance of anti-solvents.A new anti-solvent of diphenyl ether(DPE)was developed for its strong interaction with the solvents in the perovskite precursor solution.By using the anti-solvent of DPE,trap-state density of the CH3NH3PbBr3 film is reduced and the electron lifetime is enhanced along with the large-grain crystals compared with the samples from conventional anti-solvent of chlorobenzene.Upon preliminary optimization,the efficiencies of typical and semitransparent BPSCs are improved to as high as 9.54%and 7.51%,respectively.Optical absorption measurement demonstrates that the cell without metal electrode shows 80%transparency in the wavelength range of 550-1000 nm that is perfect for greenhouse vegetation.Considering that the cell absorbs light in the blue spectrum before 550 nm,it offers very high solar cell efficiency with only 17.8%of total photons,while over 60%of total photons can transm让through for photosynthesis if a transparent electrode can be obtained such as indium doped SnO2.
文摘Many of the physical and functional properties of RDX and HMX explosives are related to the crystalline structure of these materials. Crystalline defects affect the quality of the explosives. Therefore, in order to enhance the quality of these materials, it is necessary to form crystals with the lowest defects. In this research, we report the optimization of recrystallization process of RDX and HMX by statistical techniques. The solvent/anti-solvent procedure was used for recrystallization of HMX and RDX particles. The four parameters of i) ratio of anti-solvent to solvent, ii) ratio of solute to solvent, iii) aging time, and iv)cooling rate of mixture, were optimized by Taguchi analysis design. Taguchi L16 orthogonal array was used with sixteen rows corresponding to the number of tests in four columns at four levels. The apparent density of recrystallized of RDX and HMX particles was considered as the quality characteristic with the concept of "the larger-the-better". The obtained graphs showed that the studied parameters were optimized in ratio 1:1 for anti-solvent to solvent, ratio 0.1 g,m L^(-1) for solute to solvent, aging time of 2 h and cooling rate of 1℃,min^(-1). Also, the correlation between the investigated parameters and apparent density of crystals were studied by multiple linear regressions(MLR) method for obtaining a model of prediction of apparent density. The P-values were indicated that in confidence level of 95%, the null hypothesis is rejected and a meaningful addition is observed in the proposed model.
基金Financial support from The Thailand Research Fund(grant number BRG5480013)is greatly acknowledged.
文摘The objective of the present study was to alter the crystal habit of itraconazole(ITZ)by cooling and anti-solvent crystallization and characterize its properties.ITZ was recrystallized in different solvents and the effects of each solvent on morphology of crystals,dissolution behavior and solid state of recrystallized drug particles were investigated.The results revealed that ITZ crystals recrystallized by cooling and anti-solvent crystallization showed the different crystal habits from the untreated ITZ.Using cooling crystallization tended to provide needle-shaped crystals while the crystals obtained from anti-solvent crystallization showed more flaky,plate shape.This indicated the importance of preparation method on nucleation and crystal growth.No change in drug polymorphism was observed,according to determination of thermal property and crystalline state by differential scanning calorimetry and powder X-ray diffractometry,respectively.The recrystallized ITZ showed higher drug dissolution than untreated ITZ and the highest drug dissolution was observed from the samples recrystallized in the presence of PEG 200,which provided the small plate-shaped crystals with tremendously increased in surface area.However,the increasing of drug dissolution is relatively small,therefore,further development may be required.
基金the research committee of Malek-ashtar University of Technology (MUT) for supporting this work
文摘The unfavorable growth and agglomeration of micro-particles of RDX explosive was almost observed in manufacture process. For preventing of growth of micro-particles and agglomeration in anti-solvent crystallization process, the effect of additives glucose, sucrose and poly ethylene glycol-2000 and wetting solvent of isopropyl alcohol were studied. Taguchi experimental design was used for optimization of the operating conditions. The type of additive, the amount of additive(%wt.), solvent of wetting and wetting time were selected for optimization of the conditions. By using 4 factor and 3 levels, 27 experiments were conducted(L27). Results showed that in the presence of 2 %wt. of sucrose additive and isopropyl alcohol solvent, the agglomerations of particles were decreased so that a decrease 30-50% in the average of particles size was seen. Addition additives were effective in storage container and for reduce the agglomeration of particles during storage. Also, the agglomeration rate of particles was reduced over time at optimized conditions. Imaging optical microscopy, scanning electron microscopy(SEM), and particle size analyzer(PSA) methods were used for particles size analyzing as a response in statistical optimization and quality control of the final product. The sensitivity to some mechanical and shock stimuli on the RDX in presence of sucrose additive was tested and the obtained results showed the insignificant effect of additive on the safety properties of pure RDX.
文摘Self-made enriched 10 B boric acid as raw material was purified by recrystallization. The effects of final crystallization temperature, crystallization time, stirring speed, crystallization frequency and other factors on the purity were investigated. The appropriate operating condition was that the final crystallization temperature and time were 5,℃ and 10 h respectively under a low-speed stirring for crystallizing twice, which would make the purity and yield of boric acid reach 99.94% and 95.36%, respectively. Taking this as foundation, recrystallization process was optimized with acetone as anti-solvent, whose amount was the most important index. The boric acid solution was added into acetone and recrystallized under the same condition, and the purity and yield of boric acid would reach 99.98% and 99.61%, respectively. The product detected by XRD was confirmed as boric acid crystal. Main ion concentration in the product was detected by ICP, which basically met the national standard of high purity. Crystal morphology of boric acid was observed by SEM.
基金Sponsored by the National Science Research Foundation of China(20176003)
文摘In explosive research area, one of important trends is to study on the preparation technology of explosive microparticles. A new principle and method based on supercritical anti-solvent (SAS) process is put forward and discussed for the preparation of explosive micro-particles. The satisfactory micro-particles of explosives can be obtained easily by its particular mechanism of creating micro-particles, and operating conditions at normal temperature. This method is good for further study and development.
基金National Natural Science Foundation of China(20976120)the Natural Science Foundation of Tianjin(09JCYBJC06200)
文摘CeO2-ZrO2-Al2O3 ternary oxides were successfully prepared by a green route of supercritical anti-solvent precipitation with supercritical CO2 as anti-solvent and methanol as solvent. The structures and oxygen storage capacities of these ternary oxides were characterized by XRD, Raman spectra and oxygen storage capacity measurements. It was found that Al3＋ and Zr4＋ inserted into CeO2 lattice, forming CeO2-ZrO2-Al2O3 solid solution. The concentration of aluminium isopropoxide in the solution affected the concentration of oxygen vacancy and the distortion of oxygen sublattice which were responsible for the oxygen storage capacity. The rapidest oxygen uptake/release rate and maximum total oxygen storage capacity （122.0 mmolO2/molCeO2） were obtained with the aluminitun isopropoxide concentration at 0.2 wt.% in the solution.
基金Financial support from the National Natural Science Foundation of China (21476086,21776102)China Postdoctoral Science Foundation (No. 2017M612663) is greatly appreciated.
文摘To improve the physicochemical properties of astaxanthin, it was encapsulated in poly (1-lactic acid)(PLLA) using a supercritical anti-solvent (SAS) process with dichloromethane/acetone mixture as the solvent, and supercritical CO2 as the anti-solvent. The effects of altering five SAS operating cond让ions, solvent ratio, temperature, pressure, concentration of carrier, and flow rate, on the microstructure of particles were investigated using an orthogonal experimental design. Under the optimal conditions, astaxanthin/PLLA particles were produced with an encapsulation efficiency of 91.5% and a mean particle size of 954.6 nm. SEM images showed that most astaxanthin/PLLA particles were uniform microspheres. FT-IR spectra showed that the chemical structure of astaxanthin was unchanged by the SAS process. The results of chromatic difference, X-ray diffraction, thermogravimetric, and differential scanning calorimetry analyses showed that astaxanthin had been encapsulated in the PLLA matrix in an amorphous state. Overall, astaxanthin/PLLA microspheres greatly enhanced the stability of astaxanthin during storage, and the levels of residual solvents were far lower than the ICH lim让s. This means that astaxanthin/PLLA microspheres prepared using SAS show great potential for use in many food, cosmetic, and pharmaceutical formulations.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.51572072 and 21402045)Wuhan Science and Technology Bureau of Hubei Province of China (No. 2013010602010209)+1 种基金Educational Commission of Hubei Province of China(No. D20141006)Department of Science & Technology of Hubei Province of China(No. 2015CFA118)
文摘An efficient solution-processable route employing Pb(Ac)2 as lead source and anti-solvent treatment to achieve fully covered and homogenous perovskite films is reported. The effect of different solution methods and device architectures on the morphologies of perovskite films were systematically investigated. Our results show that the planar perovskite layer fabricated by one-step solution method achieved fully covered and pinhole-free films. Further anti-solvent treatment using chlorobenzene (CB) promoted a perovskite film with highly smooth surfaces and enlarged grain sizes. Device fabricated from CB treated perovskite film achieved a best PCE of 15.80%, in comparison with 14.02%for the untreated device. These results evidently suggest a feasible route towards controlling the crystallization and morphology of planar heterojunction (PHJ) PSCs for improved efficiency.
基金Project supported by National Natural Science Foundation of China(20976120)Natural Science Foundation of Tianjin(09JCYBJC06200)
文摘The nano-crystalline Cu-Ce-Zr-O composite oxides were successfully prepared by the supercritical anti-solvent （SAS） process. The physicochemical properties and catalytic performances were investigated by X-ray diffraction （XRD）, Raman spectroscopy, H2 temperature-programmed reduction （H2 -TPR）, oxygen storage capacity （OSC） measurement and catalytic activity evaluation. It was found that Cu2＋ ions incorporated into CeO2 -ZrO2 lattice to form Cu-Ce-Zr-O solid solution associated with the formation of oxygen vacancies. The Cu-Ce-Zr-O catalysts prepared via the SAS process with the Cu content 2.63 mol.% showed the highest OSC index of 636.9 μmol/g. Compared with the samples prepared by impregnation method, Cu doping using SAS process could improve the dispersion of Cu2＋ in the composite oxide, enhance the interaction between Cu2＋ and CeO2-ZrO2 , improve the reducibility of catalyst, and thus improve the OSC performance and increase the catalytic activity for CO oxidation at low temperature.
文摘In the present work, anti-solvent crystallization of artemisinin from four different organic solvents （methanol, ethanol, acetonitrile, and acetone） was studied. Water was used as anti-solvent. The effect of an impurity （quercetin） on the performance of anti-solvent crystallization of artemisinin was investigated. The fundamental process data such as solubility of artemisinin in pure organic solvents and their binary mixtures with varying composition water were measured at room temperature. The solubility of quercetin was measured only in pure organic solvents at room temperature. Anti-solvent crystallization experiments were designed based on the fundamental process data determined. Firstly, the anti-solvent crystallization of artemisinin without impurity was performed from all four organic solvents and then the experiments were repeated with addition of an impurity （quercetin） while keeping all other process parameters constant. Two different concentrations of impurity, i.e., 10% and 50% of its solubility, in the respective organic solvents at room temperature were used. The effect of impurity on performance of anti-solvent crystallization was evaluated by comparing the yield and purity of the artemisinin obtained with those in the absence of impurity. Results of the present work demonstrated that the presence of quercetin in the solution does not affect the final yield of artemisinin from the solution of each of four organic solvents used. However, the purity of artemisinin crystals were reduced when quercetin concentration was 50% of its solubility in all solvents studied.
基金supported by the National Natural Science Foundation of China(20976120)Natural Science Foundation of Tianjin(09JCYBJC06200)
文摘Hollow CuO-CeO2-ZrO2nano-particles were prepared with supercritical anti-solvent apparatus by using methanol as sol-vent and supercritical carbon dioxide as anti-solvent. Two key factors （i.e., pressure and temperature） were investigated to explore the effects of catalyst structure and physic-chemical properties （i.e., morphology, reducing property, oxygen storage capacity and specific surface area）. The resulting materials were characterized with X-ray diffraction （XRD）, high resolution transmission electron micros-copy （HRTEM）, Brunauer-Emmett-Teller （BET）,hydrogen temperature programmed reduction （H2-TPR） and oxygen storage capac-ity （OSC） measurement, respectively. The experimental results showed that lower temperatures promoted production of hollow struc-ture nano-particulates. The particle morphology also changed significantly, i.e. the solid construction was first transferred to hollow structure then back to solid construction. The optimal conditions for obtaining hollow nano-particles were determined at 45 °C, 18.0–24.0 MPa.
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supported by the National Key R&D Program of China(2019YFB1503200)the National Natural Science Foundation of China(52002105)+7 种基金the Key Research and Development Plan Project of Anhui Province(2022H11020014)the West Light Foundation of the Chinese Academy of Sciences(XAB2020YW11)the Collaborative Innovation Program of Hefei Science Center,CAS(2022HSC-CIP006)the Fundamental Research Funds for the Central Universities(JZ2021HGTB0105)the Hefei Institutes of Physical Science,Chinese Academy of Sciences Director’s Fund(YZJJ201902,YZJJZX202018)the Natural Science Foundation of Hebei Province(F2021208014)the Science and Technology Project of Hebei Education Department(QN2021063)the Science and Technology Research Project for the Colleges and Universities in Hebei Province(QN2022034)。
文摘The interface is crucial for perovskite solar cells(PSCs).However,voids at interfaces induced by the trapped hygroscopic dimethyl sulfoxide(DMSO)can reduce charge extraction and accelerate the film degradation,seriously damaging the efficiency and stability.In this work,4,4’-dinonyl-2,2’-dipyridine(DN-DP),a Lewis base with long alkyl chains is introduced to solve this problem.Theoretical calculated and experimental results confirm that the dipyridyl group on DN-DP can more strongly coordinate with Pb^(2+)than that of the S=O group on DMSO.The strong coordination effect plays a crucial role in removing the DMSO-based adduct and reducing the formation of voids.Due to the electron-donating properties of pyridine,the existence of DN-DP in the perovskite film can passivate the defects and optimize the energy level alignment of the perovskite configuration.The open-circuit voltage(VOC)of the DN-DP-based PSC is improved from 1.107 V(control device)to 1.153 V,giving rise to a power conversion efficiency(PCE)of24.02%.Furthermore,benefiting from the moisture resistance stemming from the hydrophobic nonyl group,the PCE retains 90.4%of the initial performance after 1000 h of storage in the ambient condition.
