Superhard F-carbon predicted by ab initio particle-swarm optimization methodology

A simple (5 + 6 + 7)-sp(3) carbon (denoted as F-carbon) with eight atoms per unit cell predicted by a newly developed ab initio particle-swarm optimization methodology on crystal structure prediction is proposed. F-carbon can be seen as the reconstruction of AA-stacked or 3R-graphite, and is energetically more stable than 2H-graphite beyond 13.9 GPa. Band structure and hardness calculations indicate that F-carbon is a transparent superhard carbon with a gap of 4.55 eV at 15 GPa and a hardness of 93.9 GPa at zero pressure. Compared with the previously proposed Bct-, M- and W-carbons, the simulative x-ray diffraction pattern of F-carbon also well matches the superhard intermediate phase of the experimentally cold-compressed graphite. The possible transition route and energy barrier were observed using the variable cell nudged elastic band method. Our simulations show that the cold compression of graphite can produce some reversible metastable carbons (e.g. M- and F-carbons) with energy barriers close to diamond or lonsdaleite.     

Attack on double-random-phase-encoding-based image hiding method

The double-random phase-encoding (DRPE) technique is a typical optical image encryption technique, which can also be used for image hiding. Usually, the secret image is encrypted with the DRPE technique and the encoded image is hidden into the host image via superimposition to obtain the stego-image. The attack technique on the DRPE-based image hiding method was proposed in this paper. Firstly, a randomly selected superimposition coefficient was used to approximate the original superimposition coefficient to extract the hidden encoded images from the stego-images approximately. Then, the chosen-plaintext attack technique on the DRPE-based optical image encryption technique was applied to recover the random phase masks used in the DRPE technique. The theoretical analysis indicated that, without considering the computational error, the recovered secret image via the proposed attack technique is identical to the original one. Even considering the computational error, it is identical to the secret image recovered with the original DRPE-based image hiding method, which demonstrates that the attack on the DRPE-based image hiding method is successfully achieved. The numerical simulation results demonstrated the correctness of the theoretical analysis.     

Power factors of late rare earth-doped Ca3Co2O6 oxides

Polycrystalline samples of (Ca_1−xR_x)₃Co₂O₆ with R = Gd, Tb, Dy and Ho at x=0-0.1 were synthesized and the effects of rare earth substitution on their thermoelectric properties were investigated. In the high-temperature region, the rare earth substitution resulted in an increase in the Seebeck coefficients (S), and the S values increased with decreasing ionic radius of rare earth elements in the order Gd³⁺>Tb³⁺>Dy³⁺>Ho³⁺. In contrast, the influence of rare earth substitution on the electrical resistivity was small. The high-temperature power factor was thereby improved by the late rare earth substitutions, particularly those with Ho³⁺ for Ca²⁺. For the Ho-doped samples (x≤0.05), the power factor was significantly improved by increasing Ho concentration.     

几种标准蛋白质的毛细管区带电泳的分离及其迁移行为

本文采用毛细管区带电泳分离了几种标准蛋白,研究了不同的清洗方式,不同ＰＨ的缓冲溶液等对迁移行为及分离的影响,并同时考察了迁移时间和相对迁移时间与操作电压的关系。     

一些新型含氮、硫杂官能团的杯[4]芳烃衍生物的合成

以杯[4]芳烃-1,3-二溴乙氧基衍生物1为合成平台,在K2CO3/MeCN体系中分别与乙醇胺、L-亮氨醇、2-巯基苯并咪唑、巯基乙酸乙酯反应,以49%～76%的产率合成了4种新型含氮、硫杂官能团的杯[4]芳烃衍生物2,4,5和6.化合物2进一步与异硫氰酸苯酯反应,以84%的产率得到了新型树枝状杯[4]芳烃氮、硫杂衍生物3.新化合物的结构与构象经元素分析、质谱、核磁共振谱等表征证实.     

SBA-15 Modified Carbon Paste Electrode for Rapid cTnI Detection with Enhanced Sensitivity

Cardiac troponin I (cTnI) is a cardiac muscle protein and forms a protein complextogether with troponin T and troponin C in heart. The troponin complex is broken upfollowing myocardial damage, and the individual protein components are released intothe blo…     

Effect of filament biasing on nanocrystalline-Si films deposited by hot wire chemical vapor deposition

Nanocrystalline silicon (nc-Si) films were deposited by hot wire chemical vapor deposition with applying positive or negative filament biases. These films were characterized by Raman spectroscopy, field emission scanning electron microscopy and X-ray photoelectron spectroscopy. Plasmon loss of the Si(2p) band region was shifted to higher energy due to dielectric changes with applied filament biases from negative to positive voltage. A semi-quantitative study of the valence band structure was employed to analyze the bias effect of the valance band in nc-Si networks. Nc-Si with a positive filament bias shows better microstructural properties than those with a negative bias and without biasing nc-Si films.     

The Automatical Slotted-Line System Controlled with Micro-Computer IBM 80486

This paper reports an automatical slotted-lin system which has been developed by us. This system is controlled with IBM-PC 80486. Its software is designed with C Language. It can performs a variety of measurements such as high, medium and low SWR measurement, signal source SWR, attenuation, phase shift, scattering coefficient of two port network and dielectric constant measurement etc. rapily, exately and conveniently. In this paper, the hardware composition and software design are described. A series of typical measurement results of SWR at 30MM wave-band are given. This method is adaptable for MM-Wave band and other Micro-wave band.     

An analysis on synthesizing large scales of one-dimensional silicon nano-structures by simple evaporation of sulfur-contained powders

The growth mechanism for synthesizing large scales of one-dimensional silicon nano-structures (silicon nano-wires (SiNWs) or silicon oxide nano-wires (SiO₂-NWs)) by a simple evaporation of sulfur-contained powders on silicon wafer is discussed. A novel sulfide-assisted mechanism referring to oxygen-assisted mechanism is proposed. Amongst this simple method, sulfide or pure sulfur can both assist the formation of SiNWs. The growth is fast and some SiNWs are easily oxidized to be amorphous structure of SiO₂-NWs under the low-vacuum system. The simple method suggests a useful route to achieve plenty of one-dimensional silicon nano-structures for further research.     

On Limit Sets and Discreteness Criteria for Nonelementary Subgroups of M（R^n）

In this paper, we will study the nonelementary groups of MSbius transformations in R^n and some properties are obtained. Also in this paper we will prove several theorems about discreteness criteria and group convergence of nonelementary groups of M（R^n）.