In order to develop the liquid phase sintering process of WC-Ni3Al-B composites,the preparation process of WC+Ni3Al prealloyed powder by reaction synthesis of carbonyl Ni,analytical purity Al and coarse WC powders wa...In order to develop the liquid phase sintering process of WC-Ni3Al-B composites,the preparation process of WC+Ni3Al prealloyed powder by reaction synthesis of carbonyl Ni,analytical purity Al and coarse WC powders was investigated.DSC and XRD were adopted to study the procedure of phase transformation for the 3Ni+Al and 70%WC+(3Ni+Al) mixed powders in temperature ranges of 550-1200 °C and 25-1400 °C,respectively.The results demonstrate that the formation mechanism of Ni3Al depends on the reaction temperature.Besides WC phase,there exist Ni2Al3,NiAl and Ni3Al intermetallics in the powder mixture after heat treatment at 200-660 °C,while only NiAl and Ni3Al exist at 660-1100 °C.Homogeneous WC+Ni3Al powder mixture can be obtained in the temperature range of 1100-1200 °C.The WC-30%(Ni3Al-B) composites prepared from the mixed powders by conventional powder metallurgy technology show nearly full density and the shape of WC is round.WC-30%(Ni3Al-B) composites exhibit higher hardness of 9.7 GPa,inferior bending strength of 1800 MPa and similar fracture toughness of 18 MPa-m1/2 compared with commercial cemented carbides YGR45(WC-30%(Co-Ni-Cr)).展开更多
The irrationality of existing phase field model is analyzed and a modified phase-field model is proposed for polymer crystal growth, in which the parameters are obtained from real materials and very simple to use, and...The irrationality of existing phase field model is analyzed and a modified phase-field model is proposed for polymer crystal growth, in which the parameters are obtained from real materials and very simple to use, and most importantly, no paradoxical parameters appeared in the model. Moreover, it can simulate different microstructure patterns owing to the use of a new different free energy function for the simulation of morphologies of polymer. The new free energy function considers both the cases of T〈Tm and T≥Tm, which is more reasonable than that in published literatures that all ignored the T≥Tm case. In order to show the validity of the modified model, the finite difference method is used to solve the model and different crystallization morphologies during the solidification process of isotactic polystyrene are obtained under different conditions. Numerical results show that the growth rate of the initial secondary arms is obviously increased as the anisotropy strength increases. But the anisotropy strength seems to have no apparent effect on the global growth rate. The whole growth process of the dendrite depends mainly upon the latent heat and the latent heat has a direct effect on the tip radius and tip velocity of side branches.展开更多
The phase equilibria and compositions in Mg-rich side at 300 ℃ were investigated in Mg-Zn-Ca ternary system through the equilibrated alloy method by using scanning electron microscopy,electron probe microanalysis,X-r...The phase equilibria and compositions in Mg-rich side at 300 ℃ were investigated in Mg-Zn-Ca ternary system through the equilibrated alloy method by using scanning electron microscopy,electron probe microanalysis,X-ray diffraction and transmission electron microscopy.The results show that two ternary compounds T1 and T2 can be in equilibrium with the Mg-based solid solution in Mg-Zn-Ca system.T1 phase is a linear compound with the composition region(molar fraction) of 15% Ca,20.5%-48.9% Zn and balanced Mg at 300 ℃.Its hexagonal structure parameters decrease with increasing Zn content,i.e.a=0.992-0.945 nm,c=1.034-1.003 nm.T2 phase has hexagonal structure with the composition region of 26.4%-28.4% Mg,63.2%-65.5% Zn and 7.1%-8.4% Ca.At 300 ℃,the solubility of Zn in the Mg-based solid solution increases for the addition of Ca,the maximum solubility of Zn is 3.7%.Three-phase fields consisting of--Mg+Mg2Ca+T1,--Mg+T1+T2,--Mg+T2+MgZn and MgZn+T2+Mg2Zn3 exist in the Mg-Zn-Ca system at 300 ℃.展开更多
We summarized the discovery of liquid chromatography mass spectrometry (LC-MS) based glutathione (GSH) capture of reactive metabolites in traditional Chinese medicine (TCM), which provides scientific basis for ...We summarized the discovery of liquid chromatography mass spectrometry (LC-MS) based glutathione (GSH) capture of reactive metabolites in traditional Chinese medicine (TCM), which provides scientific basis for further research and clinical application of Chinese medicine toxicity discovery. This dissertation overviews relevant literatures of GSH capture of reactive metabolites in recent years. And then we review the principles and methods of LC-MS based GSH capture of reactive metabolites, as well as the research progress in the discovery of toxicity of TCM including pyrrolizidine alkaloids, furans and quinoid species. The review shows that the representative compounds of TCM includes adonifoline, lasiocarpine, diosbulbin B and safrol are well dctected by LC-MS based GSH capture technique. And the main analytic systems of LC-MS are triple quadrupole and Q-Trap mass spectrometer. Constant neutral loss scan (CNLS), precursor ion scan (PIS) and multiple reaction monitor (MRM) are main detection methods to monitor the characteristic GSH conjugate fragmentations. The approach of LC-MS based GSH-trapped metabolites has a good application prospect in the discovery of toxic components of TCM.展开更多
Poly(vinylidene fluoride) (PVdF)-based gel polymer electrolytes with various compositions were prepared by solution casting technique. The kinetics of gelation was analyzed via the correlation between the apparent gel...Poly(vinylidene fluoride) (PVdF)-based gel polymer electrolytes with various compositions were prepared by solution casting technique. The kinetics of gelation was analyzed via the correlation between the apparent gelation rate and concentration of PVdF at a given temperature. Combination the results of the kinetics of gelation and the DSC study, it revealed that the phase separation was the major behavior and the fibrils were the major junction joints of the three-dimensional network even in the case the concentration of PVdF was higher than 25 wt%. The porous surface observed by ESEM also reflected that the phase separation took place during the gelation.展开更多
When new types of hydrate chemical inhibitor (such as hydrate anti-agglomerant) are used in offshore fields, some difficulties will be encountered in the pipe transportation processing design. In view of these diffi...When new types of hydrate chemical inhibitor (such as hydrate anti-agglomerant) are used in offshore fields, some difficulties will be encountered in the pipe transportation processing design. In view of these difficulties, a horizontal flow experiment pipe loop of transparent polypropylene pipe (25.4 mm inner diameter, 20 m long) was constructed, and some experiments were conducted. The working fluids were the mixed paraffin hydrocarbons, water and condensate oil mixtures obtained from offshore oil field. Analyzing the experimental results and adopting relevant theories of liquid-solid two-phase flow, the computational method of hydrate slurry transportation in pipe was developed. For the operating conditions of a certain multiphase pipeline, by using OLGA software, this method can be used to calculate pressure drop of the multiphase flow pipelines using anti-agglomerant, which can provide support for hydrate anti-agglomerant application.展开更多
The inter-diffusion of N,N-dimethylformamide solution of Zn(phen)2Cl2 and (NH4)2MS4 (M = W, Mo) in an H-shape tube produced crystals of Zn(phen)2WS4 1 and Zn(phen)2MoS4 2 (phen = 1,10-phenanthroline). The structures o...The inter-diffusion of N,N-dimethylformamide solution of Zn(phen)2Cl2 and (NH4)2MS4 (M = W, Mo) in an H-shape tube produced crystals of Zn(phen)2WS4 1 and Zn(phen)2MoS4 2 (phen = 1,10-phenanthroline). The structures of isomorphous complexes 1 and 2 have been determined by X-ray single-crystal structure analyses. Four nitrogen atoms from the phenanthroline ligands and two sulfur atoms from the MS42- anion forming a distorted octahedron coordinate each zinc atom. Through p-p interactions of adjacent aromatic rings of the phenanthroline ligands, a quasi one-dimensional zigzag-stacking column is formed in each complex. Complex 1 crystallizes in monoclinic space group C2/c, with a = 10.447(8), b = 22.016(9), c = 12.824(8) ? b = 103.56(6)? V = 2867.7(8) 3, Z = 4, C24H16N4S4WZn, Mr=737.90, Dc = 1.71 g/cm3, F(000) = 1424, m = 5.25 mm-1, the final R = 0.054 and Rw = 0.075 for 2315 observations with I > 3s (I). Complex 2 crystallizes in monoclinic space group C2/c, with a = 10.410(6), b = 22.095(7), c = 12.830(6) ? b = 103.19(8)? V = 2873.1(5) 3, Z = 4, C24H16MoN4S4Zn, Mr=649.99, Dc = 1.50 g/cm3, F(000) = 1296, m = 1.58 mm-1, the final R = 0.072 and Rw = 0.100 for 1631 observations with I > 3s(I).展开更多
Solidification or crystallization of phase change emulsion in the form of fine emulsion drops in a direct contact coolant at temperatures below their freezing point was studied. This work is mainly focused on the size...Solidification or crystallization of phase change emulsion in the form of fine emulsion drops in a direct contact coolant at temperatures below their freezing point was studied. This work is mainly focused on the size and shape of the generated partides from phase change emulsified fats. Size of the particles is the major or key factor being considered during their formation, however, other factors that govern the particle size and shape were also observed. The operating parameters of the process were optimized in order to obtain particles of smaller size ranges in the window of current operating conditions. The crystallization of complex emulsion maffices is very difficult to control in the bulk at desired requirement. Hence, the emulsion drop to particle formation has advan- tage in comparison with the bulk solidification or crystallization. The main objective of this work is to achieve spherical emulsion particles in a direct contact cooling system. Parameters like: stat)ility, characterization, viscos- ity, and the effect of different energy inputs were examined. Moreover, the effects of the capillary size, interracial tension, temperature of the emulsion on the particle size were also monitrored.展开更多
Objective: This study aimed to investigate, for the first time, the expression of circulating miRNAs (microRNAs) related to lipoprotein metabolism in patients with HF (heart failure). Medlods: Twenty patients wi...Objective: This study aimed to investigate, for the first time, the expression of circulating miRNAs (microRNAs) related to lipoprotein metabolism in patients with HF (heart failure). Medlods: Twenty patients with HF and 10 controls without HF were included. BNP (brain natxiuretic peptide), a marker of HF severity, plasma lipid parameters and the expression of circulating miRNAs were determined. Key findings: Total, LDL-, non-HDL- and HDL-cholesterol, txiglycerides, and apo A-I did not differ between both groups, but apo B was lower in the HF group compared to controls (p = 0.007). In respect to miRNAs, miR-33a, miR-144, miR-125, miR-30c, miR-122, miR-26a, miR-185, miR-758 and miR-106b were higher, from ten- to 25-fold, and miR-10b was lower about 4-fold, in HF group compared to controls. In HF patients a negative correlation between miR-26a and BNP, the marker of disease severity, was found (r = -0.552; p = 0.041). Conclusions: Plasma levels of miRNAs involved in HDL and LDL metabolism regulation were strikingly changed in HF patients. The negative correlation between miR-26a and BNP values may suggest the possibility of the rise of a novel biomarker or therapeutic target in HF.展开更多
Two-dimensional(2D) transition metal dichalcogenides(TMDs) have gained much attention in virtue of their various atomic configurations and band structures.Apart from those thermodynamically stable phases, plenty of me...Two-dimensional(2D) transition metal dichalcogenides(TMDs) have gained much attention in virtue of their various atomic configurations and band structures.Apart from those thermodynamically stable phases, plenty of metastable phases exhibit interesting properties. To obtain 2D TMDs with specific phases, it is important to develop phase engineering strategies including phase transition and phaseselective synthesis. Phase transition is a conventional method to transform one phase to another, while phase-selective synthesis means the direct fabrication of the target phases for2D TMDs. In this review, we introduce the structures and stability of 2D TMDs with different phases. Then, we summarize the detailed processes and mechanism of the traditional phase transition strategies. Moreover, in view of the increasing demand of high-phase purity TMDs, we present the advanced phase-selective synthesis strategies. Finally, we underline the challenges and outlooks of phase engineering of 2D TMDs in two aspects-high phase purity and excellent controllability. This review may promote the development of controllable phase engineering for 2D TMDs and even other2D materials toward both fundamental studies and practical applications.展开更多
Solid phase orientation of polymers is one of the most successful routes to enhancement of polymer properties.It unlocks the potential of molecular orientation for the achievement of a range of enhanced physical prope...Solid phase orientation of polymers is one of the most successful routes to enhancement of polymer properties.It unlocks the potential of molecular orientation for the achievement of a range of enhanced physical properties.We provide here an overview of techniques developed in our laboratories for structuring polymers by solid phase orientation processing routes,with a particular focus on die drawing,which have allowed control of significant enhancements of a single property or combinations of properties,including Young's modulus,strength,and density.These have led to notable commercial exploitations,and examples of load bearing low density materials and shape memory materials are discussed.展开更多
基金Project (2012CB723906) supported by the National Basic Research Program of China
文摘In order to develop the liquid phase sintering process of WC-Ni3Al-B composites,the preparation process of WC+Ni3Al prealloyed powder by reaction synthesis of carbonyl Ni,analytical purity Al and coarse WC powders was investigated.DSC and XRD were adopted to study the procedure of phase transformation for the 3Ni+Al and 70%WC+(3Ni+Al) mixed powders in temperature ranges of 550-1200 °C and 25-1400 °C,respectively.The results demonstrate that the formation mechanism of Ni3Al depends on the reaction temperature.Besides WC phase,there exist Ni2Al3,NiAl and Ni3Al intermetallics in the powder mixture after heat treatment at 200-660 °C,while only NiAl and Ni3Al exist at 660-1100 °C.Homogeneous WC+Ni3Al powder mixture can be obtained in the temperature range of 1100-1200 °C.The WC-30%(Ni3Al-B) composites prepared from the mixed powders by conventional powder metallurgy technology show nearly full density and the shape of WC is round.WC-30%(Ni3Al-B) composites exhibit higher hardness of 9.7 GPa,inferior bending strength of 1800 MPa and similar fracture toughness of 18 MPa-m1/2 compared with commercial cemented carbides YGR45(WC-30%(Co-Ni-Cr)).
基金This work is supported by the National Natural Science Foundation of China (No.11402210), the Natural Science Foundation of Shanxi Province (No.2012011019-2), and the Doctoral Fund of Taiyuan University of Science and Technology (No.20152024).
文摘The irrationality of existing phase field model is analyzed and a modified phase-field model is proposed for polymer crystal growth, in which the parameters are obtained from real materials and very simple to use, and most importantly, no paradoxical parameters appeared in the model. Moreover, it can simulate different microstructure patterns owing to the use of a new different free energy function for the simulation of morphologies of polymer. The new free energy function considers both the cases of T〈Tm and T≥Tm, which is more reasonable than that in published literatures that all ignored the T≥Tm case. In order to show the validity of the modified model, the finite difference method is used to solve the model and different crystallization morphologies during the solidification process of isotactic polystyrene are obtained under different conditions. Numerical results show that the growth rate of the initial secondary arms is obviously increased as the anisotropy strength increases. But the anisotropy strength seems to have no apparent effect on the global growth rate. The whole growth process of the dendrite depends mainly upon the latent heat and the latent heat has a direct effect on the tip radius and tip velocity of side branches.
基金Project(50731002) supported by the National Natural Science Foundation of ChinaProject(20082030) supported by the Natural Science Foundation of Liaoning Province,China
文摘The phase equilibria and compositions in Mg-rich side at 300 ℃ were investigated in Mg-Zn-Ca ternary system through the equilibrated alloy method by using scanning electron microscopy,electron probe microanalysis,X-ray diffraction and transmission electron microscopy.The results show that two ternary compounds T1 and T2 can be in equilibrium with the Mg-based solid solution in Mg-Zn-Ca system.T1 phase is a linear compound with the composition region(molar fraction) of 15% Ca,20.5%-48.9% Zn and balanced Mg at 300 ℃.Its hexagonal structure parameters decrease with increasing Zn content,i.e.a=0.992-0.945 nm,c=1.034-1.003 nm.T2 phase has hexagonal structure with the composition region of 26.4%-28.4% Mg,63.2%-65.5% Zn and 7.1%-8.4% Ca.At 300 ℃,the solubility of Zn in the Mg-based solid solution increases for the addition of Ca,the maximum solubility of Zn is 3.7%.Three-phase fields consisting of--Mg+Mg2Ca+T1,--Mg+T1+T2,--Mg+T2+MgZn and MgZn+T2+Mg2Zn3 exist in the Mg-Zn-Ca system at 300 ℃.
文摘We summarized the discovery of liquid chromatography mass spectrometry (LC-MS) based glutathione (GSH) capture of reactive metabolites in traditional Chinese medicine (TCM), which provides scientific basis for further research and clinical application of Chinese medicine toxicity discovery. This dissertation overviews relevant literatures of GSH capture of reactive metabolites in recent years. And then we review the principles and methods of LC-MS based GSH capture of reactive metabolites, as well as the research progress in the discovery of toxicity of TCM including pyrrolizidine alkaloids, furans and quinoid species. The review shows that the representative compounds of TCM includes adonifoline, lasiocarpine, diosbulbin B and safrol are well dctected by LC-MS based GSH capture technique. And the main analytic systems of LC-MS are triple quadrupole and Q-Trap mass spectrometer. Constant neutral loss scan (CNLS), precursor ion scan (PIS) and multiple reaction monitor (MRM) are main detection methods to monitor the characteristic GSH conjugate fragmentations. The approach of LC-MS based GSH-trapped metabolites has a good application prospect in the discovery of toxic components of TCM.
文摘Poly(vinylidene fluoride) (PVdF)-based gel polymer electrolytes with various compositions were prepared by solution casting technique. The kinetics of gelation was analyzed via the correlation between the apparent gelation rate and concentration of PVdF at a given temperature. Combination the results of the kinetics of gelation and the DSC study, it revealed that the phase separation was the major behavior and the fibrils were the major junction joints of the three-dimensional network even in the case the concentration of PVdF was higher than 25 wt%. The porous surface observed by ESEM also reflected that the phase separation took place during the gelation.
文摘When new types of hydrate chemical inhibitor (such as hydrate anti-agglomerant) are used in offshore fields, some difficulties will be encountered in the pipe transportation processing design. In view of these difficulties, a horizontal flow experiment pipe loop of transparent polypropylene pipe (25.4 mm inner diameter, 20 m long) was constructed, and some experiments were conducted. The working fluids were the mixed paraffin hydrocarbons, water and condensate oil mixtures obtained from offshore oil field. Analyzing the experimental results and adopting relevant theories of liquid-solid two-phase flow, the computational method of hydrate slurry transportation in pipe was developed. For the operating conditions of a certain multiphase pipeline, by using OLGA software, this method can be used to calculate pressure drop of the multiphase flow pipelines using anti-agglomerant, which can provide support for hydrate anti-agglomerant application.
基金grants from the National Natural Science Foundation of China the Natural Science Foundation of Fujian Province and Chinese Academy of Sciences.
文摘The inter-diffusion of N,N-dimethylformamide solution of Zn(phen)2Cl2 and (NH4)2MS4 (M = W, Mo) in an H-shape tube produced crystals of Zn(phen)2WS4 1 and Zn(phen)2MoS4 2 (phen = 1,10-phenanthroline). The structures of isomorphous complexes 1 and 2 have been determined by X-ray single-crystal structure analyses. Four nitrogen atoms from the phenanthroline ligands and two sulfur atoms from the MS42- anion forming a distorted octahedron coordinate each zinc atom. Through p-p interactions of adjacent aromatic rings of the phenanthroline ligands, a quasi one-dimensional zigzag-stacking column is formed in each complex. Complex 1 crystallizes in monoclinic space group C2/c, with a = 10.447(8), b = 22.016(9), c = 12.824(8) ? b = 103.56(6)? V = 2867.7(8) 3, Z = 4, C24H16N4S4WZn, Mr=737.90, Dc = 1.71 g/cm3, F(000) = 1424, m = 5.25 mm-1, the final R = 0.054 and Rw = 0.075 for 2315 observations with I > 3s (I). Complex 2 crystallizes in monoclinic space group C2/c, with a = 10.410(6), b = 22.095(7), c = 12.830(6) ? b = 103.19(8)? V = 2873.1(5) 3, Z = 4, C24H16MoN4S4Zn, Mr=649.99, Dc = 1.50 g/cm3, F(000) = 1296, m = 1.58 mm-1, the final R = 0.072 and Rw = 0.100 for 1631 observations with I > 3s(I).
基金the Department of Chemical Engineering,COMSATS Institute of Information Technology,Lahore,Pakistan,for relieving them from their duties,and Higher Education Commission,Pakistan(A/07/96851)for providing the financial assistance to carry out Ph D study in cooperation with the German Academic Exchange Service(DAAD)
文摘Solidification or crystallization of phase change emulsion in the form of fine emulsion drops in a direct contact coolant at temperatures below their freezing point was studied. This work is mainly focused on the size and shape of the generated partides from phase change emulsified fats. Size of the particles is the major or key factor being considered during their formation, however, other factors that govern the particle size and shape were also observed. The operating parameters of the process were optimized in order to obtain particles of smaller size ranges in the window of current operating conditions. The crystallization of complex emulsion maffices is very difficult to control in the bulk at desired requirement. Hence, the emulsion drop to particle formation has advan- tage in comparison with the bulk solidification or crystallization. The main objective of this work is to achieve spherical emulsion particles in a direct contact cooling system. Parameters like: stat)ility, characterization, viscos- ity, and the effect of different energy inputs were examined. Moreover, the effects of the capillary size, interracial tension, temperature of the emulsion on the particle size were also monitrored.
文摘Objective: This study aimed to investigate, for the first time, the expression of circulating miRNAs (microRNAs) related to lipoprotein metabolism in patients with HF (heart failure). Medlods: Twenty patients with HF and 10 controls without HF were included. BNP (brain natxiuretic peptide), a marker of HF severity, plasma lipid parameters and the expression of circulating miRNAs were determined. Key findings: Total, LDL-, non-HDL- and HDL-cholesterol, txiglycerides, and apo A-I did not differ between both groups, but apo B was lower in the HF group compared to controls (p = 0.007). In respect to miRNAs, miR-33a, miR-144, miR-125, miR-30c, miR-122, miR-26a, miR-185, miR-758 and miR-106b were higher, from ten- to 25-fold, and miR-10b was lower about 4-fold, in HF group compared to controls. In HF patients a negative correlation between miR-26a and BNP, the marker of disease severity, was found (r = -0.552; p = 0.041). Conclusions: Plasma levels of miRNAs involved in HDL and LDL metabolism regulation were strikingly changed in HF patients. The negative correlation between miR-26a and BNP values may suggest the possibility of the rise of a novel biomarker or therapeutic target in HF.
基金supported by the National Natural Science Foundation of China (21673161 and 21473124)the Science and Technology Department of Hubei Province (2017AAA114)the Sino-German Center for Research Promotion (1400)
文摘Two-dimensional(2D) transition metal dichalcogenides(TMDs) have gained much attention in virtue of their various atomic configurations and band structures.Apart from those thermodynamically stable phases, plenty of metastable phases exhibit interesting properties. To obtain 2D TMDs with specific phases, it is important to develop phase engineering strategies including phase transition and phaseselective synthesis. Phase transition is a conventional method to transform one phase to another, while phase-selective synthesis means the direct fabrication of the target phases for2D TMDs. In this review, we introduce the structures and stability of 2D TMDs with different phases. Then, we summarize the detailed processes and mechanism of the traditional phase transition strategies. Moreover, in view of the increasing demand of high-phase purity TMDs, we present the advanced phase-selective synthesis strategies. Finally, we underline the challenges and outlooks of phase engineering of 2D TMDs in two aspects-high phase purity and excellent controllability. This review may promote the development of controllable phase engineering for 2D TMDs and even other2D materials toward both fundamental studies and practical applications.
基金the support of the Engineering & Physical Sciences Research Council,the Technology Strategy Boardvarious industrial partners including Bridon International,Dow Building Products Inc and Smith & Nephew Ltd
文摘Solid phase orientation of polymers is one of the most successful routes to enhancement of polymer properties.It unlocks the potential of molecular orientation for the achievement of a range of enhanced physical properties.We provide here an overview of techniques developed in our laboratories for structuring polymers by solid phase orientation processing routes,with a particular focus on die drawing,which have allowed control of significant enhancements of a single property or combinations of properties,including Young's modulus,strength,and density.These have led to notable commercial exploitations,and examples of load bearing low density materials and shape memory materials are discussed.