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1.
本文采用高压X光衍射方法在金刚石对顶压砧中在位地(in situ)研究了Fe68Co24Ni8(wt%)合金在室温下的压致bcc→hcp结构相变和直到40.5 GPa的等温压缩行为。实验结果表明该合金在常压下为bcc结构,晶格常数a0=(0.287 0±0.000 1) nm,体积V0=(7.119±0.007) cm3/mol,密度ρ0=(7.981±0.008) g/cm3;在20.9 GPa附近出现bcc→hcp结构相变,两相共存压力区约10 GPa,在此区域内有晶面间距d(002)hcp=d(110)bcc,且原子平面(002)hcp//(110)bcc,hcp相比bcc相体积减小(0.33±0.02) cm3/mol;高压相hcp结构的晶格参数比值c/a=1.608±0.004;相变后原子配位数的增加使得hcp相(002)平面内及(002)平面间的最近邻原子间距比bcc相最近邻原子间距分别增大约1.6%和0.5%;用Murnaghan状态方程对实验数据进行最小二乘法拟合,得到bcc相B0=(130±13) GPa,B0'=12.6±0.5;hcp相V0=(6.62±0.04) cm3/mol,B0=(243±21) GPa,B0'=6.8±0.3;对于该合金的bcc→fcp相变时的结构转变机制做了详细的讨论。 相似文献
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Changlun Shao Zhiyong Guo Hong Peng Guangtian Peng Zhongjing Huang Zhigang She Yongcheng Lin Shining Zhou 《Chemistry of Natural Compounds》2007,43(4):377-380
A new isoprenyl phenyl ether, 3-hydroxy-4-(3-methylbut-2-enyloxy)benzoic acid methyl ester (1), together with 4-hydroxybenzoic acid (2), 2-hydroxy-6-methylbenzoic acid (3), and 4-hydroxy-3-methoxybenzoic acid (4) were isolated from Mangrove fungus (No. B60) from the South China Sea. The structures of the compounds were established
on the basis of NMR spectroscopic and mass spectrometric data. In the preliminary bioassay, compound 1 exhibited antibacterial and antifungal activities. Compound 1 also inhibited cytotoxicity to the hepG2 cell line with an IC50 value of 10.0 μg/mL.
Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 313–314, July–August, 2007. 相似文献
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酞菁化合物LB单分子膜的SERRS 总被引:4,自引:0,他引:4
酞菁类化合物具有优良的光电特性,选择适当的取代侧链可得到稳定的LB成膜材料,可望在微电子器件等方面获得重要的应用.本工作观测了四-4-(2,4-二特戊基苯氧基)酞菁铜(CuPc(Dt-PP)_4)在银岛膜上的LB单分子层的表面增强共振拉曼散射(SERRS)光谱。比较其固体粉末的共振拉曼散射(RRS)光谱,讨论了酞菁铜分子大环在载片表面的取向及其可能的原因。1 实验CuPc(Dt-PP)_4样品由陈文启等合成,经元素分析、IR、NMR、色谱等研究确认其结构如图1所示.银岛膜用真空蒸镀法制备在玻璃载片上。用同时蒸镀在铜网上的银膜的透射电 相似文献
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Dr. Guanjun Xiao Dr. Chunye Zhu Prof. Yanming Ma Prof. Bingbing Liu Prof. Guangtian Zou Prof. Bo Zou 《Angewandte Chemie (International ed. in English)》2014,53(3):729-733
There is an urgent need for the development in the field of the magnetism of topological insulators, owing to the necessity for the realization of the quantum anomalous Hall effect. Herein, we discuss experimentally fabricated nanostructured hierarchical architectures of the topological insulator Bi2Te3 without the introduction of any exotic magnetic dopants, in which intriguing room‐temperature ferromagnetism was identified. First‐principles calculations demonstrated that the intrinsic point defect with respect to the antisite Te site is responsible for the creation of a magnetic moment. Such a mechanism, which is different from that of a vacancy defect, provides new insights into the origins of magnetism. Our findings may pave the way for developing future Bi2Te3‐based dissipationless spintronics and fault‐tolerant quantum computation. 相似文献
7.
Xiaofei Bie Chunzhong Wang H. Ehrenberg Yingjin Wei Gang Chen Xing Meng Guangtian Zou Fei Du 《Solid State Sciences》2010,12(8):1364-1367
ZnO nanoflowers are synthesized by hydrothermal method. The morphology of ZnO is captured by SEM, TEM and HRTEM, which is composed of closely packed nanorods of about 100 nm in diameter and 1 μm in length. The ZFC/FC curves show superparamagnetic features. The abnormal increase in magnetization curves below 14 K comes from the isolated vacancy clusters with no interaction. The magnetic hysteresis at 300 K displays saturation state and confirms room-temperature ferromagnetism. While the magnetic hysteresis at 5 K shows nonsaturation state due to the enhanced effects of vacancy clusters. The O 1s XPS results can be fitted to three Gaussian peaks. The existence of medium-binding energy located at 531.16 eV confirms the deficiency of O ions at the surface of ZnO nanoflowers. 相似文献
8.
Let C be a regular semigroup with an inverse transversal C° and let C be generated by its idempotents. Following W. D. Munn and T. E. Hall’s idea, in this paper, a fundamental regular semigroup T C,C° with an inverse transversal T C,C° ° is constructed such that the following holds. For any regular semigroup S with an inverse transversal S° and 〈E(S)〉 = C, C° = C ∩ S°, there is a homomorphism φ from S to T C,C° such that the kernel of φ is the maximum idempotent-separating congruence on S, and φ satisfies: (1) φ| C is a homomorphism from C onto 〈E(T C,C°)〉 ; (2) φ| S° is a homomorphism from S° to T C,C° °. In particular, S is fundamental if and only if S is isomorphic to a full subsemigroup of T C,C°. Our fundamental regular semigroup T C,C° is isomorphic to a subsemigroup of the Hall semigroup of C but it is easier to handle. Its elements are partial transformations, and the operation—although not the usual composition—is defined by means of composition. 相似文献
9.
Wuyou Fu Shikai Liu Wenhua Fan Haibin Yang Xiaofen Pang Jing Xu Guangtian Zou 《Journal of magnetism and magnetic materials》2007
Spinel CoFe2O4 coating on the surface of hollow glass microspheres of low density was synthesized by co-precipitation method. The phase structures, morphologies, particle size, shell thickness, chemical compositions of the composites have been characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and energy dispersive X-ray spectroscopy (EDS). The results show that CoFe2O4 coating on hollow glass microspheres can be achieved, and the coating layers are constituted by CoFe2O4 nanoparticles of mean size ca. 10 nm. The as-synthesized powder materials were uniformly dispersed into the phenolic cement, then the mixture was pasted on metal plate with the area of 200 mm×200 mm as the test plate. The test of microwave absorption was carried out by the radar-absorbing materials (RAM) reflectivity far field radar cross-section (RCS) method. The results indicate that the coated CoFe2O4/hollow glass microspheres composites can be applied in lightweight and strong absorption microwave absorbers. 相似文献
10.
We present a first ab initio investigation of the electron-phonon coupling (EPC) of molecular metallic hydrogen with a Cmca structure based on the linear-response approach. This molecular metallic hydrogen with overlapping bands has an elastic instability at lower pressures (<300 GPa), but stabilizes dynamically under further compression as indicated by the absence of phonon softening, thus supporting the choice of Cmca structure as a good candidate for metallic hydrogen. Within the conventional BCS theory, the predicted critical temperature Tc is 107 K at 347 GPa, so indicating good candidacy for a high temperature superconductor. With increasing pressure, interestingly, the EPC parameter λ, hence, Tc increases, resulting from the increased electronic density of states at the Fermi level and EPC matrix element 〈I2〉, in spite of an enhanced average phonon frequency 〈ω2〉. 相似文献