The current paper focuses on the prediction of residual stresses and distortions in the Laser Powder Bed Fusion(LPBF)built Ti6Al4V thin-walled geometries using Ansys Additive Print(AAP)software which employs a layer-b...The current paper focuses on the prediction of residual stresses and distortions in the Laser Powder Bed Fusion(LPBF)built Ti6Al4V thin-walled geometries using Ansys Additive Print(AAP)software which employs a layer-by-layer accumulation of inherent strain to calculate the deformations.Isotropic and anisotropic strain scaling factors were calibrated initially within the APP software for the Ti6Al4V based single cantilever beam geometry.Subsequently,the numerical simulations were performed in APP software and computed the residual stresses and distortions for the varied process parameters including laser power,scan speed and hatch distance while maintaining the layer thickness constant for all the design iterations.The numerical predictions were compared;they were found to match reasonably well with the XRD measurements within the calibrated regime.展开更多
In drug discovery research, residual solvent measurement is an integral part of purity analysis for synthesis of a drug candidate before it is used for toxicity testing. This is usually carried out using gas chromatog...In drug discovery research, residual solvent measurement is an integral part of purity analysis for synthesis of a drug candidate before it is used for toxicity testing. This is usually carried out using gas chromatography(GC)with direct injection sample introduction. This method requires testing compounds to be soluble at high concentrations( > 50 mg/mL, usually in DMSO) to achieve acceptable sensitivity, a hurdle which is not always achievable for some samples such as cyclic peptides and oligonucleotides. To overcome the limitation associated with the direct injection approach, a new method using the Chromatoprobe thermal extraction device was developed for quantifying residual solvents of drug discovery compounds. This method not only consumes significantly less material(less than 1 mg), but also shows higher sensitivity than the direct injection approach.In addition, because no diluent is required with the Chromatoprobe thermal extraction, all residual solvents can be detected and measured without further method optimization. In our study, we compared data from GC residual solvent analysis using the Chromatoprobe solid sample introduction to those of the direct injection method for seven in-house samples. Our results showed a good agreement between the data from these two sample introduction methods. Thus, the Chromatoprobe sample introduction method provided a samplesparing alternative to the direct injection method for the measurement of residual solvents in drug discovery.This method can be particularly useful for residual solvent analysis in samples that are available only in limited amounts, poorly soluble, and/or unstable in the diluents used for the direct injection method.展开更多
Solvent residue is inevitable to occur in solution processed thin films,but its influence on the thin film quality has not been identified and addressed to date.Methylammonium acetate(MAAc)ionic liquid has recently be...Solvent residue is inevitable to occur in solution processed thin films,but its influence on the thin film quality has not been identified and addressed to date.Methylammonium acetate(MAAc)ionic liquid has recently been realized as an environmentally friendly solvent for solution processed perovskites.The specific high viscosity,low vapor pressure and strong association with perovskite precursor of the MAAc solvent is a double-edged sword,which endowed an advantageously ambient air operational and anti-solvent free perovskite deposition,but the MAAc is likely to be retained within the film and bring in detrimental effects on device performance of the corresponding solar cells.Herein,we reported a novel route to eliminate the residual solvent via a facial hydrochloric acid(HCl)annealing post-treatment(HAAP).In particular,chemical displacement reaction between the incorporated HCl and residual MAAc can be initiated to form volatile MACl and HAc,efficiently extracting MAAc residue.In the meanwhile,the stimulated mass transport via downward penetration and upward escape can trigger secondary perovskite growth with enlarged grain size and smoothened surface,leading to reduced defect state and improved interfacial contact intimacy,and also partial chloride ions are able to enter the crystal lattice to stabilize perovskite phase structure.As a result,a champion efficiency up to20.78%originating from enhanced Voc was achieved,and more than 96%of its initial efficiency can be maintained after 1000 h shelf-storage.展开更多
An analytical method for the quantification of residual solvents in annatto extracts, natural food colorants, was established using a static headspace gas chromatography (HSGC) coupled with a flame ionization detector...An analytical method for the quantification of residual solvents in annatto extracts, natural food colorants, was established using a static headspace gas chromatography (HSGC) coupled with a flame ionization detector (FID). As a sample diluent in a headspace sampling, dimethylformamide (DMF) was selected owing to its high capacity for dissolving both bixin-based and norbixin-based annatto extracts. The quantification of residual solvents was performed using the external standard method. The linearity of the calibration curves was assured with relative coefficients (R2) that were greater than 0.999. The recoveries of all standard solvents spiked in the annatto extracts were in the range from 95.1% to 107.1% to verify the accuracy and the relative standard deviation (RSD%) values (n = 3) were in the range from 0.57% to 3.31%. The quantification limits (QL) were sufficiently lower than the limits specified by Joint FAO/WHO Expert Committee on Food Additives (JECFA). With the established HSGC method, six residual solvents (methanol, ethanol, 2-propanol, acetone, ethyl acetate, and hexane) in 23 commercial annatto-extract products that consist of seven bixin-based and 16 norbixin-based products were quantified. The levels of residual ethyl acetate and hexane in all products were lower than the specified limits of JECFA. However, three samples of bixin-based products showed higher levels of residual 2-propanol (approximately 313.9 - 427.7 ppm) than the specified limit. Other bixin products also showed higher concentrations of residual methanol (approximately 166.6 - 394.7 ppm) and residual acetone (approximately 75.2 - 179.8 ppm) than the limits of JECFA. In the case of norbixin-based products, nine samples showed higher levels of residual acetone (approximately 42.6 - 139.5 ppm) than the limits of JECFA. This is the first survey of residual solvents in annatto extracts using the validated HSGC method.展开更多
Based on the characteristics of friction stir welding( FSW) and Coulomb friction work theory,the residual stresses field of FSW joints of 6 N01 aluminum alloy( T5),which was used in high speed train,were calculated by...Based on the characteristics of friction stir welding( FSW) and Coulomb friction work theory,the residual stresses field of FSW joints of 6 N01 aluminum alloy( T5),which was used in high speed train,were calculated by using the ANSYS finite element software. During the FEM calculation,the dual heat source models namely the body heat source and surface heat source were used to explore the evolution law of the welding process to the residual stress field. The method of ultrasonic residual stress detecting was used to investigate the residual stresses field of the 6 N01 aluminum alloy FSW joints. The results show that the steady-state temperature of 6 N01 aluminum alloy during FSW is about 550 ℃,and the temperature mutates at the beginning and at end of welding. The longitudinal residual stress σ_x is the main stress,which fluctuates in the range of-25 to 242 MPa. Moreover,the stress in the range of shaft shoulder is tensile stress that the maximum tensile stress is 242 MPa,and the stress in the outside of shaft shoulder is compressive stress that the maximum compressive stress is 25 MPa. The distribution of the tensile stress in the welding nugget zone( WNZ) is obviously bimodal,and the residual stress on the advancing side is higher than that on the retreating side. With the increasing of the welding speed,the maximum temperature decreased and the maximum residual stress decreased when the pin-wheel speed kept constant. With the increasing of the pin-wheel speed,the maximum temperature of the joint increased and the maximum residual stress increased when the welding speed was constant. The experimental results were in good agreement with the finite element results.展开更多
6-aminopenicillanic acid (6-APA) crystals obtained under different physical and chemical conditions of the solutions may present different habits. The habits of diamond-shaped plates are desirable compared with other ...6-aminopenicillanic acid (6-APA) crystals obtained under different physical and chemical conditions of the solutions may present different habits. The habits of diamond-shaped plates are desirable compared with other habits of 6-APA crystals. To obtain ideal 6-APA crystals, the effects of the mixed solvents and additives on 6-APA crystal habits were investigated. Ethanol or acetone was used as the organic solvent, and impurities existing in the 6-APA purification process were used as the additives. 6-APA growth habits were changed when the concentrations of ethanol, acetone or phenyl acetic acid were increased to exceed their critical concentration. The observed results show that the dominant face on 6-APA crystals was identified to be {020}, but the overall habit was controlled by the relative growth rates of the {101} and {002} faces. Crystal growth rates and habits can be appreciably changed by specific adsorption of additives on crystal faces.In some cases solvent molecules can act in a similar way and may be regarded as bulk additives. The effects of additives and organic solvents on 6-APA crystal habits were the results of adsorption effect, which fitted the experimental results quite well.展开更多
A new method of upgrading 6# solvent oils using different ionic liquids as catalysts in a continuous apparatus is studied in this paper.The results show that aromatics, olefins and small quantity of sulfurs can be rem...A new method of upgrading 6# solvent oils using different ionic liquids as catalysts in a continuous apparatus is studied in this paper.The results show that aromatics, olefins and small quantity of sulfurs can be removed simultaneously. Using complex ionic liquid modified with CuCl as catalyst, oletins are removed completely,the mass concentrations of aromatics and sulfurs in solvent oil are 0.36% and 0.0058%, respectively, and the bromic index is zero. The sulfur removal rate decreases gradually with increasing of rtmning time. The refined 6# solvent oil is corresponded to the quality standards of GB 16629-1996, which request that the mass concentrations of aromatics, sulfurs and bromic index are 1%, 0.012% and 1000, respectively. The loss of solvent oil is less than 3%.展开更多
文摘The current paper focuses on the prediction of residual stresses and distortions in the Laser Powder Bed Fusion(LPBF)built Ti6Al4V thin-walled geometries using Ansys Additive Print(AAP)software which employs a layer-by-layer accumulation of inherent strain to calculate the deformations.Isotropic and anisotropic strain scaling factors were calibrated initially within the APP software for the Ti6Al4V based single cantilever beam geometry.Subsequently,the numerical simulations were performed in APP software and computed the residual stresses and distortions for the varied process parameters including laser power,scan speed and hatch distance while maintaining the layer thickness constant for all the design iterations.The numerical predictions were compared;they were found to match reasonably well with the XRD measurements within the calibrated regime.
文摘In drug discovery research, residual solvent measurement is an integral part of purity analysis for synthesis of a drug candidate before it is used for toxicity testing. This is usually carried out using gas chromatography(GC)with direct injection sample introduction. This method requires testing compounds to be soluble at high concentrations( > 50 mg/mL, usually in DMSO) to achieve acceptable sensitivity, a hurdle which is not always achievable for some samples such as cyclic peptides and oligonucleotides. To overcome the limitation associated with the direct injection approach, a new method using the Chromatoprobe thermal extraction device was developed for quantifying residual solvents of drug discovery compounds. This method not only consumes significantly less material(less than 1 mg), but also shows higher sensitivity than the direct injection approach.In addition, because no diluent is required with the Chromatoprobe thermal extraction, all residual solvents can be detected and measured without further method optimization. In our study, we compared data from GC residual solvent analysis using the Chromatoprobe solid sample introduction to those of the direct injection method for seven in-house samples. Our results showed a good agreement between the data from these two sample introduction methods. Thus, the Chromatoprobe sample introduction method provided a samplesparing alternative to the direct injection method for the measurement of residual solvents in drug discovery.This method can be particularly useful for residual solvent analysis in samples that are available only in limited amounts, poorly soluble, and/or unstable in the diluents used for the direct injection method.
基金financially supported by the National Natural Science Foundation of China(Grants 51972172,61705102,61605073,61935017 and 91833304)Projects of International Cooperation and Exchanges NSFC(51811530018)+3 种基金the Young 1000 Talents Global Recruitment Program of Chinathe Jiangsu Specially Appointed Professor Program“Six talent peaks”Project in Jiangsu Province,Chinathe fellowship of China Postdoctoral Science Foundation(2020M672181)。
文摘Solvent residue is inevitable to occur in solution processed thin films,but its influence on the thin film quality has not been identified and addressed to date.Methylammonium acetate(MAAc)ionic liquid has recently been realized as an environmentally friendly solvent for solution processed perovskites.The specific high viscosity,low vapor pressure and strong association with perovskite precursor of the MAAc solvent is a double-edged sword,which endowed an advantageously ambient air operational and anti-solvent free perovskite deposition,but the MAAc is likely to be retained within the film and bring in detrimental effects on device performance of the corresponding solar cells.Herein,we reported a novel route to eliminate the residual solvent via a facial hydrochloric acid(HCl)annealing post-treatment(HAAP).In particular,chemical displacement reaction between the incorporated HCl and residual MAAc can be initiated to form volatile MACl and HAc,efficiently extracting MAAc residue.In the meanwhile,the stimulated mass transport via downward penetration and upward escape can trigger secondary perovskite growth with enlarged grain size and smoothened surface,leading to reduced defect state and improved interfacial contact intimacy,and also partial chloride ions are able to enter the crystal lattice to stabilize perovskite phase structure.As a result,a champion efficiency up to20.78%originating from enhanced Voc was achieved,and more than 96%of its initial efficiency can be maintained after 1000 h shelf-storage.
文摘An analytical method for the quantification of residual solvents in annatto extracts, natural food colorants, was established using a static headspace gas chromatography (HSGC) coupled with a flame ionization detector (FID). As a sample diluent in a headspace sampling, dimethylformamide (DMF) was selected owing to its high capacity for dissolving both bixin-based and norbixin-based annatto extracts. The quantification of residual solvents was performed using the external standard method. The linearity of the calibration curves was assured with relative coefficients (R2) that were greater than 0.999. The recoveries of all standard solvents spiked in the annatto extracts were in the range from 95.1% to 107.1% to verify the accuracy and the relative standard deviation (RSD%) values (n = 3) were in the range from 0.57% to 3.31%. The quantification limits (QL) were sufficiently lower than the limits specified by Joint FAO/WHO Expert Committee on Food Additives (JECFA). With the established HSGC method, six residual solvents (methanol, ethanol, 2-propanol, acetone, ethyl acetate, and hexane) in 23 commercial annatto-extract products that consist of seven bixin-based and 16 norbixin-based products were quantified. The levels of residual ethyl acetate and hexane in all products were lower than the specified limits of JECFA. However, three samples of bixin-based products showed higher levels of residual 2-propanol (approximately 313.9 - 427.7 ppm) than the specified limit. Other bixin products also showed higher concentrations of residual methanol (approximately 166.6 - 394.7 ppm) and residual acetone (approximately 75.2 - 179.8 ppm) than the limits of JECFA. In the case of norbixin-based products, nine samples showed higher levels of residual acetone (approximately 42.6 - 139.5 ppm) than the limits of JECFA. This is the first survey of residual solvents in annatto extracts using the validated HSGC method.
基金supported by the Natural Science Foundation of Hebei(Grant No.2016210050)Natural Science Foundation of Jiangsu(Grant No.BK20141181)Innovative Funding Projects of Graduate Student of Hebei(Grant No.2017010)
文摘Based on the characteristics of friction stir welding( FSW) and Coulomb friction work theory,the residual stresses field of FSW joints of 6 N01 aluminum alloy( T5),which was used in high speed train,were calculated by using the ANSYS finite element software. During the FEM calculation,the dual heat source models namely the body heat source and surface heat source were used to explore the evolution law of the welding process to the residual stress field. The method of ultrasonic residual stress detecting was used to investigate the residual stresses field of the 6 N01 aluminum alloy FSW joints. The results show that the steady-state temperature of 6 N01 aluminum alloy during FSW is about 550 ℃,and the temperature mutates at the beginning and at end of welding. The longitudinal residual stress σ_x is the main stress,which fluctuates in the range of-25 to 242 MPa. Moreover,the stress in the range of shaft shoulder is tensile stress that the maximum tensile stress is 242 MPa,and the stress in the outside of shaft shoulder is compressive stress that the maximum compressive stress is 25 MPa. The distribution of the tensile stress in the welding nugget zone( WNZ) is obviously bimodal,and the residual stress on the advancing side is higher than that on the retreating side. With the increasing of the welding speed,the maximum temperature decreased and the maximum residual stress decreased when the pin-wheel speed kept constant. With the increasing of the pin-wheel speed,the maximum temperature of the joint increased and the maximum residual stress increased when the welding speed was constant. The experimental results were in good agreement with the finite element results.
文摘6-aminopenicillanic acid (6-APA) crystals obtained under different physical and chemical conditions of the solutions may present different habits. The habits of diamond-shaped plates are desirable compared with other habits of 6-APA crystals. To obtain ideal 6-APA crystals, the effects of the mixed solvents and additives on 6-APA crystal habits were investigated. Ethanol or acetone was used as the organic solvent, and impurities existing in the 6-APA purification process were used as the additives. 6-APA growth habits were changed when the concentrations of ethanol, acetone or phenyl acetic acid were increased to exceed their critical concentration. The observed results show that the dominant face on 6-APA crystals was identified to be {020}, but the overall habit was controlled by the relative growth rates of the {101} and {002} faces. Crystal growth rates and habits can be appreciably changed by specific adsorption of additives on crystal faces.In some cases solvent molecules can act in a similar way and may be regarded as bulk additives. The effects of additives and organic solvents on 6-APA crystal habits were the results of adsorption effect, which fitted the experimental results quite well.
基金Supported by the National Natural Science Foundation of China （20676150）, the Natural Science Foundation of Beijing （2052010）, and the Science and Technology Venture Foundation of the Petro China Company Limited （2005[68]）.
文摘A new method of upgrading 6# solvent oils using different ionic liquids as catalysts in a continuous apparatus is studied in this paper.The results show that aromatics, olefins and small quantity of sulfurs can be removed simultaneously. Using complex ionic liquid modified with CuCl as catalyst, oletins are removed completely,the mass concentrations of aromatics and sulfurs in solvent oil are 0.36% and 0.0058%, respectively, and the bromic index is zero. The sulfur removal rate decreases gradually with increasing of rtmning time. The refined 6# solvent oil is corresponded to the quality standards of GB 16629-1996, which request that the mass concentrations of aromatics, sulfurs and bromic index are 1%, 0.012% and 1000, respectively. The loss of solvent oil is less than 3%.
