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Distribution and Influence of Iron Phases on the Physico-Chemical Properties of Phyllosilicates

Chinese Journal Of Geochemistry 2002年第1期21卷 29-39页

作者： MERVATSAIDHASSAN SAYEDMAHMOUDSALEM CentralMetallurgicalRandDInstitute CarioEgypt physicsdepartment FacultyofScienceAl－AzharUniversityNaserCityCairoEgypt

Clay minerals from different Cretaceous stratigraphic successions of Egypt were investigated using XRD, DTA, dissolution analysis (DCB), IR, M*issbauer and X-band Electron Spin Resonance (ESR) spectroscopies. The purity of the samples and the degree of structural order were determined by XRD. The location of Fe in the octahedral sheet is characterized by absorption bands at ～875 cm\+\{-1\} assigned as Al-OH-Fe which is present after chemical dissolution of free iron. The M*issbauer spectra of these clays show two doublets with isomer shift and quadrupole splitting typical of octahedral coordinated Fe\+\{3+\}, in addition to third doubler with hyperfine parameter typical of Fe\+\{2+\} in the spectra of Abu-Had kaolinite (H) sample. 6-lines magnetic hyperfine components which are consistent with those of hematite are confirmed in the spectra of both Isel and Rish kaolinite samples. Goethite was confirmed by both IR and DTA. Multiple nature of ESR of these clays suggested structural Fe in distorted octahedral symmetry and as non-structural Fe. Little dispersion and low swelling indices as well as incomplete activation of investigated montmorillonite samples by NaCO\-3 appear to be due to incomplete disaggregation of montmorillonite particles. This can be explained by the ability of Fe-gel to aggregate the montmorillonite into pseudo-particles and retard the rigid-gel structure. However, extraction of this ferric amorphous compound by dithonite treatment recovers the surface properties of the montmorillonite samples. On the other hand, amounts and site occupation of Fe associated with kaolinite samples show a negative correlation with the parameters used to describe the degree of crystalline perfection, color, brightness and vitrification range of these kaolinite samples.

关键词：白垩纪铁相矿物学物理化学性质光谱学结晶度页硅酸盐矿物

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Study of the imaging property of a fluorescent confocal microscopy with a phase-only filter in an extended source

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Optoelectronics Letters 2007年第4期3卷 299-302页

作者： YANG Chu-ping KUANGWei-min Li Hai physicsdepartment SouthChinaAgriculturalUniversityGuangzhou510642China

The phase information of an enlarged source is reconstructed with an annular two-zone phase-only filter in a fluorescent confocal scanning optical microscope for resolution improvement. The dependences of its resolution on the source size and on the phase transmission of the outer annular zone of the falter are investigated theoretically by use of its three-dimensional optical transfer function （3D OTF ）. The increased source size and the required phase value of the outer annular zone of the phase-only falter for an optimal 3D OTF of the optical system are presented.

关键词：成像特性荧光共焦显微镜滤光器相位信息

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Identification of Vibrational States in 230T（n,f） Reaction

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Communications in Theoretical Physics 2001年第1期35卷 67-70页

作者： A.N.Behkami Z.Kargar 等 physicsdepartment ShirazUniversityShirazIran

The excitation function for the fission of 230Th induced by neutrons has an unusual maximum for neutron energies in the vicinity of 700KeV,It has been suggested that this maximum may be associated with the vibrational-mode resonance states,The unusual peak in the excitation function is interpreted in terms of a vibrational-model resonance state in a two-humpted fission *** theoretical fits to the fission cross sections and angular distributions,it is shown that the resonance has K=1/2.

关键词：核裂变液滴模型壳模型对关联

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Analytic Solution of Strongly Coupling Schroedinger Equations

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Communications in Theoretical Physics 2004年第4期41卷 502-508页

作者： LIAOJin-Feng ZHANGPeng-Fei physicsdepartment TsinghuaUniversityBeijing100084China

A recently developed expansion method for analytically solving the ground states of strongly coupling Schroedinger equations by Friedberg, Lee, and Zhao is extended to excited states and applied to power-law central forces for which scaling properties are proposed. As examples for application of the extended method, the Hydrogen atom problem is resolved and the low-lying states of Yukawa potential are approximately obtained.

关键词：解析解薛定谔方程耦合量子力学 Yukawa势

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Variable Separation and Derivative-Dependent Functional Separable Solutions to Generalized KdV Equations

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Communications in Theoretical Physics 2003年第4X期40卷 401-406页

作者： ZHANGShun-Li LOUSen-Yue physicsdepartment ShanghaiJiaoTongUniversityShanghai200030China SchoolofMathematics UniversityofNew-SouthWalesSydneyNSW2052Australia

Using the generalized conditional symmetry approach, a complete list of canonical forms for the Korteweg de-Vries type equations with which possessing derivative-dependent functional separable solutions (DDFSSs) is ob... 详细信息

关键词：变量分离条件对称 KdV型方程非线性扩散方程进化矢量场

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Phase Transitions of a Dilute O（n） Model

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Communications in Theoretical Physics 2004年第6期41卷 911-916页

作者： GUOWen-An HenkW.J.B1ote LIUYuan-Yuan physicsdepartment BeijingNormalUniversityBeijing100875~China FacultyofAppliedSciences DelftUniversityofTechnologyP.O.Box50462600GADelftTheNetherlands

We investigate tricritical behavior of the O(n) model in two dimensions by means of transfer-matrix and finite-size scaling methods. For this purpose we consider an O(n) symmetric spin model on the honeycomb lattice with vacancies; the tricritical behavior is associated with the percolation threshold of the vacancies. The vacancies are represented by face variables on the elementary hexagons of thelattice. We apply a mapping of the spin degrees of freedom model on a non-intersecting-loop model, in which the number n of spin components assumes the role of a continuously variable parameter. This loop model serves as a suitable basis for the construction of the transfer *** results reveal the existence of a tricritical line, parametrized by n, which connects the known universality classes of the tricritical Ising model and the theta point describing the collapse of a polymer. On the other side of theIsing point,the tricritical line extends to the n = 2 point describing a tricritical O(2) model.

关键词： phase transition dilute O(n) model tricritical behavior transfer matrix

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Energies of 1s~2ng and 1s~2nh (n = 5, 6, 7, and 8) States for LithiumIsoelectronic Sequence

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Communications in Theoretical Physics 2005年第5期43卷 886-890页

作者： CHENChao WANGZhi-Wen physicsdepartment LiaoningNormalUniversityDalian116029China CenterforAtomicandMolecularNanosciences DepartmentofPhysicsTsinghuaUniversityBeijing100084China

The nonrelativistic energies for lithium isoelectronic sequence 1s~2ng and1s~2nh (n = 5,6,7, and 8) states from Z = 3 to 8 are calculated by using a full core pluscorrelation (FCPC) method with multiconGguration interaction wave functions. Relativistic andmass-polarization effects on the energy are evaluated as the first-order perturbation theory. Ourpredicted excitation energies are compared with previous experimental results in the literature.

关键词： lithium-like system full-core plus correlation excitation energy

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Effect of Pb Ions on the Ionic Conductivity of Some Silicate Glass Systems

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Journal of Materials Science & Technology 2002年第5期18卷 391-394页

作者： A.G.Mostafa Z.A.El-Hadi 等 physicsdepartment FacultyofScienceAl-AzharUniversityNasrCityCairoEgypt ChemistryDepartment UniversityCollegeforGirlsAinShamsUniversityCairoEgypt

Conductivity of glasses in the systems ***, (where R=Ca, Sr or Ba) was investigated between room temperature and 530 K. The dependence of log resistivity as well as the activation energy on the PbO content has been studied. Based on the present experimental results, the possible different conduction mechanisms in such glasses are discussed. It was postulated that Pb2+ ions may represent the major charge carrying species in these glasses. This assumption was confirmed by the calculations of the mean distance between the interstitial Pb2+ ions and the effective center of the O2- ions in the glass networks. The variation in the values of the density and the molar volume with PbO content is also discussed in view of the obtained activation energies for the studied glass-systems.

关键词： Ionic conductivity Pb ion Silicate glass systems

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Application of nanotechnology in a silver/graphite contact material and optimization of its physical and mechanical properties

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Rare Metals 2004年第1期23卷 79-83页

作者： YUHaifeng LEIJingxuan MAXueming ZHULihui LUYao XIANGJing WENGWei SchoolofMaterialsScienceandTechnology ShanghaiUniversity.Shanghai200072.China physicsdepartment.EastChinaNormalUniversity.Shanghai200062 China ShanghaiElectricalApparatusResearchInstitute.Shanghai200063.China

By applying nanotechnology, a new type of silver/graphite (AgC) electricalcontact was fabricated and characterized. The AgC coating powders were obtained through high-energyball milling and reducer liquid spraying-coating method. The as-prepared powders were examined bytransmission electron microscope (TEM), scanning electron microscope (SEM), and X-ray diffraction(XRD). The results show that the thickness of graphite flakes milled for 10 h is about 50-60 nm andthe AgC coating powders exhibit flocculent structure with quite fine and homogeneous internalmicropores. XRD implies that the average crystalline size of silver in coating powders is about 50nm. The mechanical and physical properties of this newly developed AgC contact made from theabove-mentioned nanocrystalline powders by traditional powder metallurgy technique were *** with its counterparts made from other techniques, the properties of this new AgC contacthave been optimized. High surface energy and high-energy interfaces of the nanocrystalline AgCcoating powders provide powerful driving force for sintering densification. Moreover, the flocculentstructure of the powders is also an important factor to acquire fine density ratio.

关键词： contact material AgC-N (newly developed) nanotechnology high-energy ballmilling reducer liquid spraying-coating method optimization

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Current-Voltage Characteristics of Molecular Devices at Low Bias

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Chinese Physics Letters 2004年第7期21卷 1247-1250页

作者： LIAOYun-Xing CHENHao R.Note H.Mizuseki Y.Kawazoe NationalKeyLaboratoryofSurfacePhysics FudanUniversityShanghai200433 physicsdepartment FudanUniversityShanghai200433 InstituteforMaterialsResearch TohokuUniversitySendai980-8577Japan

We use density functional theory and the Green function formalism with charge energy effect included in the self-consistent calculation of the I–V characteristics of a single benzene ring with an appendage of cf3, and identify some interesting properties of the I–V characteristics at low bias. The molecule picks up a fractional charge at zero bias, then the additional fractional charge produces a barrier on the junction of the molecule and contacts to perturb current flow on the molecule. This phenomenon may be useful for the design of future molecular devices.

关键词： Molecules

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