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排序方式: 共有4503条查询结果,搜索用时 15 毫秒
21.
Pan Mingxiang Wei Bingchen Xia Lei Wang Weihua Zhao Deqian Zhang Zhi Han Bao Shan 《Intermetallics》2002,10(11-12)
Bulk Nd–Al–Fe–Co glassy alloys with diameter up to 5 mm were investigated by magnetic measurements, magnetic force microscopy (MFM) and high resolution electron microscopy (HREM) at room temperature. The results from the measurement of vibrating sample magnetometer show that these samples with compositions Nd65Al10Fe25-xCox (x=0–10 at.%) and Nd60Al10Fe20Co10 display hard magnetic properties with HC of 300 kAm−1, MS of 10 Am2 kg−1, and Mr of 7 Am2 kg−1. The MFM measurements of the Nd60Al10Fe20Co10 bulk metallic glass (BMG) reveal the existence of magnetic domains with a period of about 0.36 μm, and the ordered clusters with the averaged size of about 5 nm was observed by the HREM on the sample. The domain structure or cluster is believed to be associated with the appearance of hard-magnetic properties in this alloy system. The existence of the large-size domains demonstrates that magnetic moment of a great deal of ordered atomic clusters in the BMG has been aligned by exchange-coupling. 相似文献
22.
Wang Weihua Xu Wenjie Song Weilin Yang Bin Li Li Guo Xuhong Wu Lianghua Liu Hongxing 《Catalysis Letters》2021,151(8):2326-2338
Catalysis Letters - Novel Mo-V-PMMA and Mo-V-PS catalysts are prepared by addition of hard polymethyl methacrylate (PMMA) and polystyrene (PS) nanospheres into Mo/V compounds in the preparation... 相似文献
23.
对刘勰批评体系建构的探讨,是《文心雕龙》研究中最富有成效的学术领域之一.然而,从中国传统文学批评的内在连贯性或系统性出发,探讨这一系统性著作的研究却明显匮乏.用这种大视野来集中审视《文心雕龙》的文学观念,会有如下发现:从远古到汉代,中国文学批评形成了三种主要的文学观:以《尚书》为代表的宗教文学观,以《左传》和《国语》为代表的人文文学观,和以《毛诗序》为代表的教化文学观.刘勰继承了前人把文学理解为一个和谐过程的基本模式,重新认识了文学的性质、起源、思想和语言的形成及其功能,从而形成了自己的综合文学观.这四种文学观之间的联系揭示了一个复杂的批评体系.这驳斥了人们普遍认为的中国传统批评没有一个连贯体系的错误观点. 相似文献
24.
为探究双孔爆破时炮孔间距和额外自由面对爆破过程中爆破损伤的影响,基于RHT(Riedel-Hiermaier-Thoma)损伤本构建立了多组三维数值模型,利用模型损伤云图研究不同爆破条件下的岩石爆破过程,通过自定义变量—有效损伤率的变化探究炮孔周围岩石损伤的时空演化过程。结果表明:随着炮孔间距的增加,岩石有效损伤率逐渐递减,相同截面处的有效损伤率在炮孔间距最小的方案中最大,相邻炮孔间的爆破能量叠加作用随炮孔间距的增大而减弱,合适的炮孔间距可以获得更加理想的爆破效果;岩石有效损伤率随着自由面到炮孔中心处距离的增大而逐渐减小,爆破能量倾向于向自由面方向传播,额外自由面对爆破能量分布的影响随自由面与炮孔间距的增大而减弱。数值模拟结果对研究双孔爆破能量的传递法则具有一定的借鉴意义。 相似文献
25.
26.
Kinetics of synthesis of Li4Ti5O12 through solid-solid reaction 总被引:1,自引:0,他引:1
CHPU Kuo-Chih QIU Weihua WU Ke ZHANG Guohua 《稀有金属(英文版)》2006,25(5):399-406
1. Introduction The solid-solid reaction used in synthesizing various kinds of electrochemical materials has many advantages, such as simple process, without using solvent, saving energy, friendly to the environment and easy to obtain good quality materials like nano-size materials. Recently, the manufacturing of electrochemistry materials has been paid more atten- tion due to its increasing needs. Therefore it is a natural interest to study the synthesis of electro- chemical materials by usin… 相似文献
27.
28.
Xiangming He Weihua Pu Li Wang Jianguo Ren Changyin Jiang Chunrong Wan 《Electrochimica acta》2007,52(11):3651-3653
A novel process was proposed to synthesize nano Sb-encapsulated pyrolytic polyacrylonitrile composite for anode material in lithium secondary batteries. The preparation started with the dissolution of SbCl3 and polyacrylonitrile (PAN) in dimethylformamide (DMF) solution, followed by the addition of KBH4 to reduce Sb3+ in the solution. The Sb composite was obtained by pyrolysis of the Sb/PAN mixture that precipitated out when the DMF solution was added by plentiful water. The TEM analysis showed that about 100-200 nm Sb particles were embedded by the pyrolyzed PAN, which provided a conductive matrix to relieve the morphological change of Sb during electrochemical cycling. As-prepared composite presented good cycleability for lithium storage. The proposed process paves an effective way to prepare high performance alloy based composite anode materials for high performance lithium-ion batteries. 相似文献
29.
新型无机抗菌剂的研究现状和展望 总被引:3,自引:0,他引:3
介绍了无机抗菌剂的国内外发展现状,评述了各种无机抗菌剂的结构特点及抗菌机理,介绍了无机抗菌剂在陶瓷、塑料、纤维等方面的应用,同时探讨了无机抗菌剂存在的问题及发展趋势。 相似文献
30.
Isao Tanaka Ken'ichiro Igashira Taira Okamoto Koichi Niihara Rowland M. Cannon 《Journal of the American Ceramic Society》1995,78(3):673-679
High-purity Si3 N4 (with 2.5 wt% glassy SiO2 ) doped with 0 to 450 at.ppm of Ca was prepared as a model system to investigate the effects of grain-boundary segregants on fracture phenomenology at 1400°C. Subcritical crack-growth (SCG) resistance as well as creep resistance was degraded significantly by the presence of a small amount of Ca. The internal friction of the doped materials exhibited the superposition of a grain-boundary relaxation peak and a high-temperature background, and the apparent viscosity of the grain-boundary film was determined from the peak. Based on these experimental data, the fracture mechanism at 1400°C was divided into three regions: "brittle," SCG, and creep failure as a function of both external strain rate and Ca concentration, C Ca . From the investigation of the C Ca dependence of the critical strain rate for the transition from "brittle" to SCG fractures, the SCG phenomenon is suggested to be triggered by small-scale, grain-boundary sliding. The C Ca dependence of "steady-state" creep rate was far from the theoretical dependence of diffusional creep via a solution-precipitation mechanism. The discrepancy was interpreted to be due to the presence of an impurity-insensitive creep component. This component may correspond to the lowest limit of the tensile creep rate in Si3 N4 polycrystalline materials containing intergranular glassy-SiO2 film. 相似文献