Magnetoresistance and magnetic properties of Fe3O4 nanoparticle compacts

In this paper,we report on the magnetic properties of Fe3O4 nanoparticles with different grain sizes under different pressures.In all the samples,the saturated magnetization Ms shows a linear decrease with increasing pressure.The thickness of the magnetic dead layer on the nanoparticle surface nuder different pressures was roughly estimated,which also increases with increasing pressure.The transport measurements of the nanoparticle Fe3O4 compacts show that the low-field magnetoresistance (MR) value is insensitive to the grain size in a wide temperature range;however,the high-field MR value is dependent on grain size,especially at low temperatures.These experimental results can be attributed to the different surface states of the nanoparticles.     

特性异常的发光管的分析研究

介绍了二类不同结构的(表面和侧面发射型)红外发光二极管.研究和分析了它们在低频大电流脉冲注入下的Pp—Ip特性和直流注入下的光谱特性.结果表明:正常情况下,器件具有线性的Pp—Ip特性,直流注入下的发射光谱具有高斯分布形状,对于Burrus表面发射型器件,在0—3A的峰值脉冲电流注入下,部分器件具有的异常Pp—Ip特性:线性-亚线性-超线性区.在20—100mA的直流电流注入下,部分器件的发射光谱具有多峰状.     

Compact operators whose real and imaginary parts are positive

Let be a compact operator on a Hilbert space such that the operators and are positive. Let be the singular values of and the eigenvalues of , all enumerated in decreasing order. We show that the sequence is majorised by . An important consequence is that, when is less than or equal to , and when this inequality is reversed.

     

Inter- and intra-molecular H-bonds induced different nanostructures from a multi-H-bonding (MHB) amphiphile: nanofibers and nanodisks

An MHB amphiphile, N-stearoyl-l-glutamic acid (C(18)-Glu), forms disk- and fiber-like nanostructures respectively in hydrophilic and hydrophobic environments due to the inter- and intra-molecular H-bonds.     

Nonclassical Properties of Orthonormalized Eigenstates of the Operator (a q f(N q )) k

In this paper, the completeness of the k orthonormalized eigenstates of the operator (a _q f(N _q )) ^k (k 3) is proved. We introduce a new kind of higher order squeezing and an antibunching. The properties of the Mth-order squeezing and the antibunching effect of the k states are investigated. The result shows that these states may form a complete Hilbert space, and the Mth order [M = (m + 1/2)k;m = 0,1,2,. . .] squeezing effects exist in all of the k states when k is even. There is the antibunching effect in all of the states.     

Synthesis,crystal structure and properties of a one-dimensional polymeric copper(II) complex of tetrachlorophthalate

The coordination polymer [Cu₂L₂(H₂O)₆ · 2(H₂O)] _n (L = -tetrachlorophthalate dianion) has been synthesized and characterized by X-ray crystallography, i.r. spectroscopy, electronic spectroscopy and cyclic voltammetry. The structure of the complex is a one-dimensional zigzag chain. The i.r. spectra reveal that the tetrachlorophthalate groups are bismonodentate ligands, and this is confirmed by the crystal structure determination. Cyclic voltammetry reveals two steps of a quasi-reversible oxidation–reduction processes for the complex.     

A linear comprehensive adsorption model of hydrogen on super activated carbon under supercritical conditions

The adsorption isotherms of hydrogen on super activated carbon were measured systematically, covering a temperature range of 93-293 K at 20 K intervals and pressures up to 7 MPa. All the experimental data were linearized by adopting the coordinates ln ln(n) vs 1/(ln P). The results indicate that the adsorption limit (P(lim), n(lim)) exists virtually at high pressure and has a certain physical meaning. Based on the adsorption limit, further analyses were carried out by modeling the adsorption isotherms in the coordinates ln(n(lim)/n) vs ln(RT(ln(P(lim)/P) and a linear comprehensive adsorption model was proposed in the form n (lim)=n.exp(psi T+lambda/T-c/) (beta).[RT ln( P (lim)P )] (b) which can predict the adsorption isotherm of hydrogen on activated carbon in supercritical conditions.     

LiNi1-xAlxO2(x=0～1.0)固溶体结构的XRD研究

利用溶胶凝胶法制备了新型锂离子二次电池正极材料LiNi_1-xAl_xO₂(x=0,0.1～1.0)固溶体,X射线衍射结果表明,在0≤x≤1范围内,材料均为具有α-NaFeO₂型结构的LiNi_1-xAl_xO₂固溶体单相.随着Al固溶量的增加,晶胞参数发生变化,a轴缩短,c/a比增大,晶胞体积V₀减小,材料的层状属性更加明显.