The cross-sectional distortion usually appears during rotary-draw bending process of thin-walled rectangular tube with small bending radius.To study the cross-sectional distortion of the tube,a three-dimensional finit...The cross-sectional distortion usually appears during rotary-draw bending process of thin-walled rectangular tube with small bending radius.To study the cross-sectional distortion of the tube,a three-dimensional finite-element model of the process was developed based on ABAQUS/Explicit code and its reliability was validated by experiment.Then,the cross-sectional distortion behaviors of the tube were investigated.The results show that a zone of larger circumferential stress appears on the tube when bending angle reaches 30°.And in the larger circumferential stress zone,the sagging phenomenon is produced obviously.The maximum cross-sectional distortion is located in the larger circumferential stress zone and the angle between the plane of maximum cross-sectional distortion and the bending reference plane is about 50°.The position of the maximum cross-sectional distortion keeps almost unchanged with the variation of the clearances between dies and tube.展开更多
Crossed beams scattering study was carried out on the F＋HD→DF＋H reaction using high- resolution H-atom Rydberg tagging time-of-flight technique. Vibrational state-resolved differential cross sections were measured,...Crossed beams scattering study was carried out on the F＋HD→DF＋H reaction using high- resolution H-atom Rydberg tagging time-of-flight technique. Vibrational state-resolved differential cross sections were measured, with partial rotational state resolution, at eight collision energies in the range of 2.51-5.60 kJ/mol. Experimental results indicated that the product angular distributions are predominantly backward scattered. As the collision energy increases, the backward scattered peak becomes broader gradually. Dependence of product vibration branching ratios on the collision energy was also determined. The experimental results show that the DF products are highly inverted in the vibrational state distribution and the DF （v＇=3） product is the most populated state. Furthermore, the DF （v＇=l） product has also been observed at collision energy above 3.97 kJ/mol.展开更多
Two novel FeII spin crossover complexes [Fe(L1)3](BF4)25H2O (1) and [Fe(L2)3](BF4)2·2H2O (2) with 4-NHR-1,2,4-triazole (R = isopropyl, L1; cyclohexyl, L2) were synthesized. 1 and 2 remain white at room temperatur...Two novel FeII spin crossover complexes [Fe(L1)3](BF4)25H2O (1) and [Fe(L2)3](BF4)2·2H2O (2) with 4-NHR-1,2,4-triazole (R = isopropyl, L1; cyclohexyl, L2) were synthesized. 1 and 2 remain white at room temperature, whereas they turn purple at liquid temperature. Variable temperature optical detection and magnetic susceptibilities measurement show that the spin-crossover phenomenon for 1 was observed between 120 K and 170 K. The hysteresis loop is about 10 K. The Tc temperature of 2 is 190 K, but no thermal hysteresis loop was found. The molar thermodynamic functions and the microscopic parameters were obtained from the theoretical analysis in terms of the domain model, two level Ising model and regular solution model, respectively.展开更多
基金Projects(50575184,50975235) supported by the National Natural Science Foundation of ChinaProject(YF07057) supported by Science and Technology Development Program of Xi'an City,Shaanxi Province,China+1 种基金Project(NPU-FFR-200809) supported by Foundation for Fundamental Research of Northwestern Polytechnical University,ChinaProject(08-3) supported by State Key Laboratory of Materials Processing and Die & Mould Technology,Huazhong University of Science and Technology,China
文摘The cross-sectional distortion usually appears during rotary-draw bending process of thin-walled rectangular tube with small bending radius.To study the cross-sectional distortion of the tube,a three-dimensional finite-element model of the process was developed based on ABAQUS/Explicit code and its reliability was validated by experiment.Then,the cross-sectional distortion behaviors of the tube were investigated.The results show that a zone of larger circumferential stress appears on the tube when bending angle reaches 30°.And in the larger circumferential stress zone,the sagging phenomenon is produced obviously.The maximum cross-sectional distortion is located in the larger circumferential stress zone and the angle between the plane of maximum cross-sectional distortion and the bending reference plane is about 50°.The position of the maximum cross-sectional distortion keeps almost unchanged with the variation of the clearances between dies and tube.
基金V. ACKNOWLEDGMENTS This work was supported by the Chinese Academy of Sciences, the Ministry of Science and Technology, and the National Natural Science Foundation of China.
文摘Crossed beams scattering study was carried out on the F＋HD→DF＋H reaction using high- resolution H-atom Rydberg tagging time-of-flight technique. Vibrational state-resolved differential cross sections were measured, with partial rotational state resolution, at eight collision energies in the range of 2.51-5.60 kJ/mol. Experimental results indicated that the product angular distributions are predominantly backward scattered. As the collision energy increases, the backward scattered peak becomes broader gradually. Dependence of product vibration branching ratios on the collision energy was also determined. The experimental results show that the DF products are highly inverted in the vibrational state distribution and the DF （v＇=3） product is the most populated state. Furthermore, the DF （v＇=l） product has also been observed at collision energy above 3.97 kJ/mol.
基金supported by the National Natural Science Foundation of China(Grant Nos.90101028,50173011 and 50172021)the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institutions of MOE,China.
文摘Two novel FeII spin crossover complexes [Fe(L1)3](BF4)25H2O (1) and [Fe(L2)3](BF4)2·2H2O (2) with 4-NHR-1,2,4-triazole (R = isopropyl, L1; cyclohexyl, L2) were synthesized. 1 and 2 remain white at room temperature, whereas they turn purple at liquid temperature. Variable temperature optical detection and magnetic susceptibilities measurement show that the spin-crossover phenomenon for 1 was observed between 120 K and 170 K. The hysteresis loop is about 10 K. The Tc temperature of 2 is 190 K, but no thermal hysteresis loop was found. The molar thermodynamic functions and the microscopic parameters were obtained from the theoretical analysis in terms of the domain model, two level Ising model and regular solution model, respectively.
