Synthesis of Ag/AgCl-mesoporous silica nanocomposites using a simple aqueous solution-based chemical method and a study of their antibacterial activity on E. coli

Simple aqueous solution-based chemical methods have been developed for the synthesis of Ag/AgCl nanoparticle-mesoporous silica nanocomposites. Ag loading in the mesoporous silica was accomplished using a wet-impregnation method. The AgCl-mesoporous silica nanocomposite material(AgCl-mSi) was synthesized by using a 'one pot' method. Synthesized materials were characterized using X-ray diffraction,N2 adsorption-desorption analysis and high-resolution transmission electron microscopy. Antibacterial activity of...     

Studies in cyclocopolymerization. VI. Copolymerization of trimethylvinylsilane and dimethyldivinylsilane with maleic anhydride

This paper reports the results of copolymerization of trimethylvinylsilane and dimethyldivinylsilane, respectively, with maleic anhydride. The former forms a 1:1 alternating copolymer while the latter, being a 1,4-pentadiene, forms a 1:2 cyclocopolymer. Consistent with the theory that charge-transfer complexes are involved in certain copolymerizations, it has been shown in this work that both of the vinyl silanes studied form charge-transfer complexes with maleic anhydride. The stoichiometric composition of these complexes have been shown by ultraviolet analysis to be 1:1 molar complexes. The equilibrium constants for complexation of trimethylvinylsilane and dimethyldivinylsilane with maleic anhydride have been determined by NMR and are 0.061 and 0.1071./mole, respectively.     

含瞬时态、具有突变率的广义生-灭Q-矩阵(I)

研究含瞬时态、具有突变率的广义生-灭拟q-矩阵,给出易于验证的Q过程存在性准则,并构造出全部Q过程和全部诚实Q过程,证明了不需附加任何条件,所有诚实Q过程都是常返的,给出诚实Q过程是遍历的充要条件,并求出其遍历测度,以及证明了不存在可配称Q过程.最后给出两个例子以说明我们的结果易于验证.     

CENTRAL LIMIT THEOREMS FOR A BRANCHING RANDOM WALK WITH A RANDOM ENVIRONMENT IN TIME

We consider a branching random walk with a random environment in time, in which the offspring distribution of a particle of generation n and the distribution of the displacements of its children depend on an environment indexed by the time n. The environment is supposed to be independent and identically distributed. For AR, let Zn(A) be the number of particles of generation n located in A. We show central limit theorems for the counting measure Zn(·) with appropriate normalization.     

Detailed investigation of optimized alkali catalyzed transesterification of Jatropha oil for biodiesel production

The non-edible oils are believed to be one of the major feedstock for the production of biodiesel in future.In the present study,we investigated the production of Jatropha oil methyl esters(JOMEs) via alkali-catalyzed transesterification route.The biophysical characteristics of Jatropha oil were found within the optimal range in accordance with ASTM standards as a substitute diesel fuel.The chemical composition and production yield of as-synthesized biodiesel were confirmed by various analytical techniques such as FT-IR,1H NMR,13 C NMR and gas chromatography coupled with mass spectrometry.A high percentage conversion,～96.09%,of fatty acids into esters was achieved under optimized transesterification conditions with 6 :1 oil to methanol ratio and 0.9 wt% Na OH for 50 min at ～60°C.Moreover,twelve fatty acids methyl esters(FAME) were quantified in the GC/MS analysis and it was interesting to note that the mass fragmentation pattern of saturated,monounsaturated and diunsaturated FAME was comparable with the literature reported values.     

Study of the short-term release of the ionic fraction of heavy metals from dental amalgam into synthetic saliva, using anodic stripping voltammetry with microelectrodes

The present paper describes a fast and reproducible procedure, employing differential pulse stripping analysis technique with graphite microelectrodes, for the quantitative evaluation of the ionic fraction of heavy metals (namely Hg, Cu, and Zn) released from dental amalgams into synthetic saliva during 6-90 h contact between amalgam and saliva, after completion of the dental restoration (short-term release). The Zn(2+) concentration was evaluated by linear calibration, whereas Cu(2+) and Hg(2+) contents were estimated by the standard additions method. While the concentration of Zn(2+) ion does not increase significantly anymore after a 6-h contact (values from 288+/-12 to 346+/-12 mugdm(-3) at time of contact from 6 to 90 h, respectively), in the same time interval the concentration of both Cu(2+) and Hg(2+) ions progressively increases (from 38+/-6 to 197+/-4 mugdm(-3) and from 15+/-3 to 101+/-2 mugdm(-3), respectively). The results of the release tests reveal that Hg concentration is at the highest level of risk (HBM III), as identified by the three human biomonitoring categories suggested by the Institut für Wasser-, Boden- und Lufthygiene des Umweltbundesamtes (Germany) for the estimation of potential harmful effects on health due to exposure to heavy metals.     

线性分子对称群的不可约表示和f轨道的对称性

研究了Ｃ∞ｖ和Ｄ∞ｈ群的不可约表示，并志出了在Ｃ∞ｖ，Ｄ－∞ｈ，Ｃ２ｖ和Ｃ３ｖ群中ｆ轨道所属的对称性。     

Thermodynamic properties of cubic ZrC under high pressure from first-principles calculations

The elastic and thermodynamic properties of Zirconium carbide (ZrC) are investigated by ab initio plane-wave pseudopotential density function theory method. The obtained lattice constant, elastic constant and bulk modulus B are consistent with the experimental and theoretical data. Through the quasi-harmonic Debye model, the dependences of the normalized volume V/V ₀ and the bulk modulus B on pressure P, as well as the specific heat C _V on the temperature T are obtained successfully. The relationships of the thermal expansion α with temperature and pressure are also investigated, which indicate the temperature hardly has any effect on the thermal expansion α at high pressure. Supported by the National Natural Science Foundation of China (Grant No. 10776022)     

人工神经网络参数调整对生物光谱识别的影响

本文介绍了一种利用反向传播人工神经网络 (BP ANN)对生物可见光谱进行识别的方法。利用自组的光纤探头式光谱仪对苹果的疤痕和烂痕微区表面进行部分可见光范围 (5 0 0～ 730nm)的光谱测量 ,采用具有单隐层的BP ANN对光谱数据进行分析 ,以便对生物表面性质实现自动识别。本文着重就神经网络的输出值范围、训练方式、隐层数及不同程度的噪音信号等对神经网络识别精度的影响做了较为详尽的讨论。