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961.
Jiliang Zhang Yong-Mook Kang Guangcun Shan Svilen Bobev 《Acta Crystallographica. Section C, Structural Chemistry》2019,75(5):562-567
The crystal structure of the gadolinium iron bismuthide Gd6FeBi2 has been characterized by single‐crystal X‐ray diffraction data and analyzed in detail using first‐principles calculations. The structure is isotypic with the Zr6CoAl2 structure, which is a variant of the ZrNiAl structure and its binary prototype Fe2P (Pearson code hP9, Wyckoff sequence g f d a). As such, the structure is best viewed as an array of tricapped trigonal prisms of Gd atoms centered alternately by Fe and Bi. The magnetic‐ordering temperature of this compound (ca 350 K) is much higher than that of other rare‐earth metal‐rich phases with the same or related structures. It is also higher than the ordering temperature of many other Gd‐rich ternary phases, where the magnetic exchange is typically governed by Ruderman–Kittel–Kasuya–Yosida (RKKY) interactions. First‐principles calculations reveal a larger than expected Gd magnetic moment, with the additional contribution arising from the Gd 5d electrons. The electronic structure analysis suggests strong Gd 5d–Fe 3d hybridization to be the cause of this effect, rather than weak interactions between Gd and Bi. These details are of importance for understanding the magnetic response and explaining the high ordering temperature in this material. 相似文献
962.
Ling-Bin Kong Mao-Cheng Liu Jun-Wei Lang Min Liu Yong-Chun Luo Long Kang 《Journal of Solid State Electrochemistry》2011,15(3):571-577
A new porous cobalt hydroxide film has been successfully electrodeposited on nickel foam from 0.1?M cobalt nitrate electrolyte at ?1.0?V vs. SCE without adding any surfactant. The microstructure and surface morphology of prepared cobalt hydroxide films were physically characterized by X-ray diffraction analysis and scanning electron microscopy. The results indicate that an interlaced network structure was obtained. The effects of electrodeposition time, deposition potential, and different substrates on the specific capacitance and microstructure of prepared porous ??-Co(OH)2 thin film were systematically studied. The results indicate that the film deposited on nickel foam at ?1.0?V has excellent electrochemical properties. A maximum specific capacitance of 1473?F?g?1 could be achieved at a current density of 2?A?g?1. 相似文献
963.
Ai‐Zheng Chen Xi‐Ming Pu Yun‐Qing Kang Li Liao Ya‐Dong Yao Guang‐Fu Yin 《Macromolecular rapid communications》2006,27(15):1254-1259
Summary: 5‐Fluorouracil‐poly(L ‐lactide) (5‐Fu‐PLLA) microparticles have been prepared by an SEDS process. First, the 5‐Fu is successfully micronized and is then used to produce the 5‐Fu‐PLLA microparticles. The 5‐Fu‐PLLA microparticles synthesized by the SEDS process exhibit a rather spherical shape and a narrow particle size distribution, where it ranges from 615 to 1 990 nm, with a mean particle size of 980 nm. The dichloromethane residue in the 5‐Fu‐PLLA microparticles without any further treatment is 46 ppm. The average drug load and encapsulation efficiency of the 5‐Fu‐PLLA microparticles are 3.05 and 17.8%, respectively. The rate of drug release from the 5‐Fu‐PLLA microparticles shows mainly first‐order kinetics.
964.
Xia Xiao Hai-Peng Song Yi-Lan Kang Xiao-Lei Li Xiao-Hua Tan Hao-Yun Tan 《Acta Mechanica Sinica》2012,28(2):432-437
A three-nested-deformation model is proposed to describe crack-tip fields in rubber-like materials with large deformation.The model is inspired by the distribution of the measured in-plane and out-of-plane deformation.The inplane displacement of crack-tip fields under both Mode I and mixed-mode(Mode I-II) fracture conditions is measured by using the digital Moire’ method.The deformation characteristics and experimental sector division mode are investigated by comparing the measured displacement fields under different fracture modes.The out-of-plane displacement field near the crack tip is measured using the three-dimensional digital speckle correlation method. 相似文献
965.
In this paper, we consider the existence of at least three positive solutions of singular nonlocal boundary value problems for systems of nonlinear second-order ordinary differential equations. The associated Green’s function for the boundary value problems is first given. The proofs of our main results are based upon the Leggett–Williams fixed point theorem. Finally, we give an example to demonstrate our result. 相似文献
966.
967.
968.
We introduce the time-consistency concept that is inspired by the so-called “principle of optimality” of dynamic programming
and demonstrate – via an example – that the conditional value-at-risk (CVaR) need not be time-consistent in a multi-stage
case. Then, we give the formulation of the target-percentile risk measure which is time-consistent and hence more suitable
in the multi-stage investment context. Finally, we also generalize the value-at-risk and CVaR to multi-stage risk measures
based on the theory and structure of the target-percentile risk measure. 相似文献
969.
Two new vanadates, Ba(2.5)(VO2)3(SeO3)4.H2O and La(VO2)3(TeO6).3H2O, have been synthesized by hydrothermal methods using BaCO3, Ba(OH)2.H2O, La(NO3)3.6H2O, V2O5, TeO2, and H2SeO3 as reagents. The structures were determined by single-crystal X-ray diffraction. Ba(2.5)(VO2)3(SeO3)4.H2O exhibits a two-dimensional layered structure consisting of VO(5) square pyramids and SeO3 polyhedra, whereas La(VO2)3(TeO6).3H2O has a three-dimensional framework structure composed of VO(4) tetrahedra and TeO6 octahedra. Infrared and Raman spectroscopy, UV-vis diffuse reflectance spectroscopy, and thermogravimetric analysis are also presented. Crystal data: Ba(2.5)(VO2)3(SeO3)4.H2O, trigonal, space group P (No. 147) with a = b = 12.8279(15) A, c = 7.2631(9) A, V = 1035.1(2) A(3), and Z = 2; La(VO2)3(TeO6).3H2O, trigonal, space group R3c (No. 161) with a = b = 9.4577(16) A, c = 23.455(7) A, V = 1816.9(7) A3, and Z = 6. 相似文献
970.
Lee PH Mo J Kang D Eom D Park C Lee CH Jung YM Hwang H 《The Journal of organic chemistry》2011,76(1):312-315
Pd-catalyzed cross-coupling reactions of aryl iodides containing not only an electron-donating group but also an electron-withdrawing group on the aryl ring with organoindium reagents generated in situ from indium and ethyl 4-bromo-2-alkynoates produced selectively ethyl 2-aryl-2,3-alkadienoates in good yield. 相似文献