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91.
THEANALYTICALSTUDYONTHELASERINDUCEDREVERSE-PLUGGINGEFFECTBYUSINGTHECLASSICALELASTICPLATETHEORY(Ⅰ)-TEMPERATUREFIELDSZhouYichun... 相似文献
92.
In this paper, we prove that for holonomic nonconservative dynamical system the Poincaré and Poincaré-Cartan integral invariants
do not exist. Instead of them, we introduce the integral variants of Poincaré-Cartan's type and of Poincare's type for holonomic
nonconservative dynamical systems, and use these variants to solve the problem of nonlinear vibration. We also prove that
the integral invariants introduced in references [1] and [2] are merely the basic integral variants given by this paper.
Project supported by National Natural Science Foundation of China 相似文献
93.
94.
A crack terminating at an interface of two dissimilar elastic materials is investigated. It is found that the asymptotic stress
field near the crack tip is in general composed of two parts with each part being characterized by one singularity. The detailed
relation of the two singularities with the bimaterial properties is given for some special cases of the crack. 相似文献
95.
96.
本文根据反射式焦散线-伪焦散线法和弹塑性断裂力学的基本原理,推导出裂纹尖端形状方程,为测量裂纹尖端的张开位移,提供一种全新的实验方法,本文还引用实例来进行验证. 相似文献
97.
Xiaoling Lü Jimin Huang Shuhui Lv Wenyue Dong Yanwei Li Yu Shen Zhenjun Si Qian Duan Yisong Zheng 《Physics letters. A》2019,383(33):125984
We performed density functional theory calculations to investigate the electronic and magnetic properties of H-terminated zigzag BC2N nanoribbons (ZBC2NNRs) with the atoms arranged as B-C-N-C along zigzag lines. The ribbons can be classified into three groups according to the profiles of band structures and edge atoms: BN-BN, CC-CC and BN-CC. Among them, CC-CC and BN-CC ZBC2NNRs behave magnetic ground states. The results show that the CC-CC ZBC2NNR is an antiferromagnetic (AFM) semiconductor. Under the transverse electric field, the half-metallicity of 16-CC-CC ZBC2NNR can be achieved with electric field in the range of VÅ?1. Interestingly, the intrinsic half-metallicity exists in BN-CC ZBC2NNRs when the ribbon width is smaller than ~29.2 Å. For larger ribbon width (~33.5 Å), the system could be converted from ferromagnetic metal to half-metals at a very low critical field of VÅ?1. Meanwhile, it is also shown that the I–V characteristic of BN-BN ZBC2NNRs shows a negative differential resistance (NDR) effect. These ample electronic and magnetic properties might open great opportunities for BC2N materials in spintronics and nanoscale device in the future. 相似文献
98.
Xiang Cui Yu‐meng Shen Shu Jiang Da‐wei Qian Er‐xin Shang Zhen‐hua Zhu Jin‐ao Duan 《Journal of separation science》2019,42(8):1520-1527
In this study, a rapid and highly sensitive ultra high performance liquid chromatography with triple quadrupole mass spectrometry method with the mobile phase of acetonitrile and 0.1% aqueous formic acid was established and successfully applied to comparatively analyze main active components after their compatibility. Besides, the effects of Scutellariae Radix, Coptidis Rhizoma and combined extracts on type 2 diabetic rats induced by high‐fat diet along with low dose of streptozocin were investigated. Under the optimized chromatographic conditions, good separation of seven target components was achieved within 12 min. All calibration curves exhibited good linearity (R2 ≥ 0.999). The relative standard deviation of precision, repeatability and stability varied from 0.69 to 2.23, 0.98 to 2.56, and 0.92 to 2.57%, respectively. The recovery ranged from 91.11 to 105.35%. The contents of seven active components were notably reduced after compatibility; however, the hypoglycemic effect of combined extracts was stronger than single drug by decreasing the activities of fructose‐1,6‐bisphosphatase, glucose 6‐phosphatase, phosphoenolpyruvate carboxykinase and increasing the activities of glucokinase, phosphofructokinase, pyruvate kinase. Accordingly, the established analytical method was accurate and sensitive enough for quantitative evaluation of seven investigated compounds. Moreover, the combined extract had definite effects on type 2 diabetes through multiple components against multiple targets. 相似文献
99.
Mathematical Programming - We investigate in this paper the generalized trust region subproblem (GTRS) of minimizing a general quadratic objective function subject to a general quadratic inequality... 相似文献
100.
Yueqiang Cao Hao Zhang Shufang Ji Zhijun Sui Zheng Jiang Dingsheng Wang Francisco Zaera Xinggui Zhou Xuezhi Duan Yadong Li 《Angewandte Chemie (International ed. in English)》2020,59(28):11647-11652
Atomic regulation of metal catalysts has emerged as an intriguing yet challenging strategy to boost product selectivity. Here, we report a density functional theory‐guided atomic design strategy for the fabrication of a NiGa intermetallic catalyst with completely isolated Ni sites to optimize acetylene semi‐hydrogenation processes. Such Ni sites show not only preferential acetylene π‐adsorption, but also enhanced ethylene desorption. The characteristics of the Ni sites are confirmed by multiple characterization techniques, including aberration‐corrected high‐resolution scanning transmission electron microscopy and X‐ray absorption spectrometry measurements. The superior performance is also confirmed experimentally against a Ni5Ga3 intermetallic catalyst with partially isolated Ni sites and against a Ni catalyst with multi‐atomic ensemble Ni sites. Accordingly, the NiGa intermetallic catalyst with the completely isolated Ni sites shows significantly enhanced selectivity to ethylene and suppressed coke formation. 相似文献