研究了尾巨桉、巨尾桉、尾叶桉、蓝桉及小叶桉这5种桉木的材性特征及其预处理-碱性过氧化氢化学机械浆（P-RC APMP）制浆性能。结果表明：5种桉木的综纤维素质量分数在77.96%-81.36%之间,小叶桉最高,巨尾桉最低;木质素质量分数在23.18%-...研究了尾巨桉、巨尾桉、尾叶桉、蓝桉及小叶桉这5种桉木的材性特征及其预处理-碱性过氧化氢化学机械浆（P-RC APMP）制浆性能。结果表明：5种桉木的综纤维素质量分数在77.96%-81.36%之间,小叶桉最高,巨尾桉最低;木质素质量分数在23.18%-26.62%之间,尾叶桉的最高,巨尾桉最低;纤维平均长度在755-785μm之间,差异较小。采用P-RC APMP制浆方法,在H2O2用量5%,Na OH用量4.5%浸渍条件下,小叶桉的制浆得率最高,达86.7%,巨尾桉最低,仅为84.2%;在相同加拿大游离度（300 m L CSF）下,蓝桉浆的强度性能和光学性能最优,纸浆的抗张强度和白度分别达30.13（N·m）/g和82.5%（ISO）,且所需磨浆电耗最低,仅1 188 k Wh/t,巨尾桉浆的强度性能和光学性能最差,纸浆的抗张强度和白度分别为16.9（N·m）/g和73.8%（ISO）,且所需磨浆电耗最高,约为1 370 k Wh/t。展开更多
The relation between microscopic properties (e.g., layer thickness, easy axis orientation) and the macroscopic magnetic properties such as remanent magnetization of the ferromagnetic multilayer system is investigated ...The relation between microscopic properties (e.g., layer thickness, easy axis orientation) and the macroscopic magnetic properties such as remanent magnetization of the ferromagnetic multilayer system is investigated based on a simple micromagnet approach. We concentrate on a multilayer design with periodic boundary condition, where alternating soft/hard layers build a nanostructured multilayer. For any easy axis direction in the soft and hard layers a simple explicit expression of remanence of the system has been derived analytically. We find that the remanence clearly depends on the thickness of the soft magnetic layer and is nearly independent of the thickness of hard magnetic layer. On the other hand, the remanence increases upon reducing the angle enclosed by the saturation magnetization and the easy axis directions of soft magnetic layer. However, it is unsensitive to the easy axis direction of hard magnetic layer, but there exists a maximum remanence for a certain easy axis direction of hard magnetic layer.展开更多
Adopting an elastic-viscoplastic, the asymptotic problem of mode I propagat ing crack-tip field is investigated. Various asymptotic solutions resulting from the analysis of crack growing programs are presented. The an...Adopting an elastic-viscoplastic, the asymptotic problem of mode I propagat ing crack-tip field is investigated. Various asymptotic solutions resulting from the analysis of crack growing programs are presented. The analysis results show that the quasi-statically growing crack solutions are the special case of the dynamic propagating solutions. Therefore these two asymptotic solutions can be unified.展开更多
Cu-based chalcogenides have received increasing attention as promising thermoelectric materials due to their high efficiency,tunable transport properties,high elemental abundance and low toxicity.In this review,we sum...Cu-based chalcogenides have received increasing attention as promising thermoelectric materials due to their high efficiency,tunable transport properties,high elemental abundance and low toxicity.In this review,we summarize the recent research progress on this large family compounds covering diamond-like chalcogenides and liquid-like Cu2X (X=S,Se,Te)binary compounds as well as their multinary derivatives.These materials have the general features of two sublattices to decouple electron and phonon transport properties.On the one hand,the complex crystal structure and the disordered or even liquid-like sublattice bring about an intrinsically low lattice thermal conductivity.On the other hand, the rigid sublattice constitutes the charge-transport network, maintaining a decent electrical performance.For specific material systems,we demonstrate their unique structural features and outline the structure-performance correlation. Various design strategies including doping,alloying,band engineering and nanostructure architecture,covering nearly all the material scale,are also presented.Finally,the potential of the application of Cu-based chalcogenides as high-performance thermoelectric materials is briefly discussed from material design to device development.展开更多
On the basis of the proposed structures of jiangrines C and D, a synthetic strategy was initiated from D-glyceraldehyde acetonide,a readily available chiral material. Through a linear seven-step synthesis, the target ...On the basis of the proposed structures of jiangrines C and D, a synthetic strategy was initiated from D-glyceraldehyde acetonide,a readily available chiral material. Through a linear seven-step synthesis, the target molecules were accomplished. However, all characteristic data of the synthetic 3 and 4 were found to be different from those of natural jiangrines C and D. Accordingly, the molecular structures of jiangrines should be revised and a possible molecular skeleton for them was proposed.展开更多
文摘研究了尾巨桉、巨尾桉、尾叶桉、蓝桉及小叶桉这5种桉木的材性特征及其预处理-碱性过氧化氢化学机械浆（P-RC APMP）制浆性能。结果表明：5种桉木的综纤维素质量分数在77.96%-81.36%之间,小叶桉最高,巨尾桉最低;木质素质量分数在23.18%-26.62%之间,尾叶桉的最高,巨尾桉最低;纤维平均长度在755-785μm之间,差异较小。采用P-RC APMP制浆方法,在H2O2用量5%,Na OH用量4.5%浸渍条件下,小叶桉的制浆得率最高,达86.7%,巨尾桉最低,仅为84.2%;在相同加拿大游离度（300 m L CSF）下,蓝桉浆的强度性能和光学性能最优,纸浆的抗张强度和白度分别达30.13（N·m）/g和82.5%（ISO）,且所需磨浆电耗最低,仅1 188 k Wh/t,巨尾桉浆的强度性能和光学性能最差,纸浆的抗张强度和白度分别为16.9（N·m）/g和73.8%（ISO）,且所需磨浆电耗最高,约为1 370 k Wh/t。
文摘The relation between microscopic properties (e.g., layer thickness, easy axis orientation) and the macroscopic magnetic properties such as remanent magnetization of the ferromagnetic multilayer system is investigated based on a simple micromagnet approach. We concentrate on a multilayer design with periodic boundary condition, where alternating soft/hard layers build a nanostructured multilayer. For any easy axis direction in the soft and hard layers a simple explicit expression of remanence of the system has been derived analytically. We find that the remanence clearly depends on the thickness of the soft magnetic layer and is nearly independent of the thickness of hard magnetic layer. On the other hand, the remanence increases upon reducing the angle enclosed by the saturation magnetization and the easy axis directions of soft magnetic layer. However, it is unsensitive to the easy axis direction of hard magnetic layer, but there exists a maximum remanence for a certain easy axis direction of hard magnetic layer.
文摘Adopting an elastic-viscoplastic, the asymptotic problem of mode I propagat ing crack-tip field is investigated. Various asymptotic solutions resulting from the analysis of crack growing programs are presented. The analysis results show that the quasi-statically growing crack solutions are the special case of the dynamic propagating solutions. Therefore these two asymptotic solutions can be unified.
基金supported by the National Key Research and Development Program of China (2018YFB0703600)the National Natural Science Foundation of China (51625205)+3 种基金 the Key Research Program of Chinese Academy of Sciences (KFZD-SW-421)Program of Shanghai Subject Chief Scientist (16XD1403900)Youth Innovation Promotion Association, CAS (2016232)Shanghai Sailing Program (18YF1426700).
文摘Cu-based chalcogenides have received increasing attention as promising thermoelectric materials due to their high efficiency,tunable transport properties,high elemental abundance and low toxicity.In this review,we summarize the recent research progress on this large family compounds covering diamond-like chalcogenides and liquid-like Cu2X (X=S,Se,Te)binary compounds as well as their multinary derivatives.These materials have the general features of two sublattices to decouple electron and phonon transport properties.On the one hand,the complex crystal structure and the disordered or even liquid-like sublattice bring about an intrinsically low lattice thermal conductivity.On the other hand, the rigid sublattice constitutes the charge-transport network, maintaining a decent electrical performance.For specific material systems,we demonstrate their unique structural features and outline the structure-performance correlation. Various design strategies including doping,alloying,band engineering and nanostructure architecture,covering nearly all the material scale,are also presented.Finally,the potential of the application of Cu-based chalcogenides as high-performance thermoelectric materials is briefly discussed from material design to device development.
基金supported by the National Natural Science Foundation of China (21290180, 21322205, 21321061)the Open Fund of State Key Laboratory of Natural Medicines (SKLNMKF201601)
文摘On the basis of the proposed structures of jiangrines C and D, a synthetic strategy was initiated from D-glyceraldehyde acetonide,a readily available chiral material. Through a linear seven-step synthesis, the target molecules were accomplished. However, all characteristic data of the synthetic 3 and 4 were found to be different from those of natural jiangrines C and D. Accordingly, the molecular structures of jiangrines should be revised and a possible molecular skeleton for them was proposed.
