高发明
硬度理论和新型超硬材料的设计制备技术。
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- 姓名:高发明
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学术头衔:
博士生导师
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学科领域:
材料科学基础学科
- 研究兴趣:硬度理论和新型超硬材料的设计制备技术。
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579
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成果数
9
【期刊论文】Bonding and Moissbauer Isomer Shifts in (Hg, Pb)-1223 Cuprate
高发明, GAO, Fa-iMing*, a, TIAN Yong-Juna, CHEN Yana, LI Dong-Chuna, DONG Hai-Feng a, ZHANG Si-Yuan b
CHINESE JOURNAL OF CHEMISTRY 2003, 21, 108-111,-0001,():
-1年11月30日
By using the chemical bond theory of dielectric description, the chemical bond parmneters of (Hg, Pb)-1223 were calculated. The results show that the (Ba, Sr)-O and Ca-O types of bond have higher ionic character, while the Or-O and (Hg, Pb)-O types of bond have more covalent character. Mshauer isomer shifts of STFe and mSn doped in (Hg, Pb)-1223 were calculated by using the chemical eaviromncntal factor, he, defined by covalency and electronic polarizabih'ty. Four valence state tin and three valence iron sites were identified in STFe and mSn doped (Hg, ffo)-1223 super-conductor. It can be conduded that all of the Fe atoms substitute the Cu at square planar Cu(1) site, whereas Sn profers to substitute the square pyramidal Cu(2) site.
chemical bond,, Msssbauer isomer shift,, superconductor
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高发明, Fa-ming Gao, Dong-chun Li, and Si-yuan Zhang
J. Phys.: Condens. Matter 15(2003)5079-5084,-0001,():
-1年11月30日
Barium hexaferrite was synthesized by chemical co-precipitation. Its Mossbauer spectra were obtained. A semi-empirical model, based on the Phillips theory of bonding, has been developed for quantitative explanation of the M
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高发明, Fa-ming Gao
J. Phys.: Condens. Matter 15(2003)L637-L641,-0001,():
-1年11月30日
The nature of the impurity centre in LiNbO3 has been a subject of intense discussion in recent years. A semi-empirical model, based on the Phillips theory of bonding, has been developed to provide a quantitative explanation of the nephelauxetic effect of Cr3+ ions and M
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【期刊论文】Chemical bond properties and M
高发明, FamingGao a, *, Dongchun Li a, JulongHe a, Yongjun Tian a, Dongli Yu a, Siyuan Zhang b
Physica C 371(2002)151-155,-0001,():
-1年11月30日
By usingthe chemical bond theory of complex crystals, the chemical bond properties of REBa2Cu3O7 (RE=Eu, Y) were calculated. The calculated covalencies for Cu(1)-O and Cu(2)-O bond in REBa2Cu3O7 compounds are 0.41 and 0.28 respectively. Mossbauer isomer shifts of 57Fe doped, and 119Sn doped in REBa2Cu3O7-x were calculated by using the chemical environmental factor, he, defined by covalency and electronic polarizability. Four valence state tin ion and iron ion sites were identified in 57Fe and 119Sn doped REBa2Cu3O7 x superconductors.
Superconductivity, Oxides, Chemical bond, M
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【期刊论文】INVESTIGATION OF MECHANISM OF NEPHELAUXETIC EFFECT
高发明, FAMING GAO, and SIYUAN ZHANG*
I. Phys. Chem Salids Vol. 58, No.12, pp. 1991-1994, 1997,-0001,():
-1年11月30日
By using the chemical bond theory of dielectric description and electronic structure of 3d elements, the mechanism of nephelauxetic effect is studied, and the main factors responsible for this effect are identified. These are: the covalency of chemical bond, polarizabilities ofligand bond volume for the host and the valence and slain state of the center ion. Relationships between these factors are given, and the results are discussed.
A., Racah parameter,, A., 3d elements,, A., chemical bond,, D., nephelauxetic effect,, D., covatency
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【期刊论文】Origin of hardness in nitride spinel materials
高发明, Faming Gao, , *, Rui Xu, and Kuan Liu
PHYSICAL REVIEW B 71, 052103(2005),-0001,():
-1年11月30日
The nitride spinels are of considerable interest. The structural parameters of the nitride spinels have been calculated by first-principles. A semiempirical model for the hardness is employed to predict the hardness of nitride spinels and related compounds. The studies show that the influence of the electronic density, the bond strength, and the ionicity on the hardness of g-A3N4 sA=C, Si, Ged all decrease monotonously in the order of g-C3N4, g-Si3N4, and g-Ge3N4. The origin of superhardness in the group-IV nitride spinels results mainly from AtN4 tetrahedral units rather than on AoN6 octahedral units. The detailed studies of the nitride polymorphs experimentally detected and theoretically proposed indicate that the increasing of coordination cannot always result in the increasing of hardness. It has to be emphasized that the relation between the coordination numbers and hardness has to be applied with care.
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【期刊论文】Hardness estimation of complex oxide materials
高发明, Faming Gao*
PHYSICAL REVIEW B 69, 094113(2004),-0001,():
-1年11月30日
Hardness is too complex to be described by first principles. Based on the dielectric chemical bond theory, a semiempirical approach for the evaluation of the hardness of ionic oxide crystals has been proposed. It was applied to predict the hardness of complex crystals such as the optical crystals yttrium aluminum garnet, the LaMgAl11O19 aluminates, and the high-Tc superconductor YBa2Cu3O7. The calculated values were in agreement with the available experimental ones. The simplicity of the approach allows a broader class of researchers to access the method easily and to calculate the hardness of materials even using only a hand-calculator. Finally, the correlation between bond length and hardness in oxide crystals has been studied. The physical nature of the hardness of ionic crystals has been further discussed.
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【期刊论文】Origin of Superhardness in Icosahedral B12 Materials
高发明, Faming Gao, * Li Hou, and Yunhua He
J. Phys. Chem. B 2004, 108, 13069-13073,-0001,():
-1年11月30日
Boron-rich phases with icosahedral symmetry are quite intriguing. It is important to understand the origin of hardness of boron-rich materials. By starting from a chemical bond viewpoint, a simple method for evaluating hardness of boron-rich phases is presented. This method has been applied to some materials such as R-B12, B13C2, and B12X2 (X) O, P, As), and the predicted hardnesses are in agreement with available experimental values. The results show that this approach provides a powerful tool for predicting superhardness when searching for novel superhard materials in boron-rich phases by first principles.
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【期刊论文】Hardness of Covalent Crystals
高发明, Faming Gao, Julong He, ErdongWu, Shimin Liu, Dongli Yu, Dongchun Li, Siyuan Zhang, and Yongjun Tian, , *
PHYSICAL REVIEW LETTERS, 2003, 91,-0001,():
-1年11月30日
Based on the idea that the hardness of covalent crystal is intrinsic and equivalent to the sum of the resistance to the indenter of each bond per unit area, a semiempirical method for the evaluation of hardness of multicomponent crystals is presented. Applied to BC2N crystal, the predicted value of hardness is in good agreement with the experimental value. It is found that bond density or electronic density, bond length, and degree of covalent bonding are three determinative factors for the hardness of a polar covalent crystal. Our method offers the advantage of applicability to a broad class of materials and initializes a link between macroscopic property and electronic structure from first principles calculation
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