On the Observation Effects of Higgs Particle in e+e—→bb Z0 and tt－Z0 at LEP Ⅱ and NLC

According to the Minimal Standard Model and the Extended Standard Model with two Higgs doublets, we calculated the total cross sections and differential cross sections for the e⁺e^—→bb Z⁰ and tt－Z⁰ at the LEP Ⅱ and NLC energies in order tO study the possible observational effects of the Higgs particle. We found that the observation for the e⁺e^—→bb Z⁰ can give the information on the Higgs particle as long as the mass of the Higgs particle M_H≤140GeV. However, for the e⁺e^—→tt－Z⁰ the effect from Higgs particle will be completely suppressed by the electrowead background and cannot be observed, no matter whether the Higgs particle is heavy or light.     

超疏水多孔硅的制备及表面稳定性

在加热条件下采用氢化硅烷化反应对多孔硅表面进行改性,通过扫描电子显微镜、红外光谱及元素分析等手段表征了多孔硅改性前后的结构和组成,研究了不同反应时间对其性能的影响.结果表明,反应3 h后制得了超疏水表面的多孔硅,其在碱性及空气环境中具有良好的稳定性.     

某航空橡胶密封材料成分分析

采用红外光谱法对某航空橡胶密封材料成分进行定性分析,结果表明,该样品的胶种为硫化甲基硅橡胶,有机助剂为邻苯二甲酸二辛酯(DOP),无机灰分为氧化锌、硫酸钙,含量为4%。使用红外光谱法分析航空密封橡胶成分是一种经济且快速的分析方法。     

Synthesis of hierarchical hollow silica microspheres containing surface nanoparticles employing the quasi-hard template of poly(4-vinylpyridine) microspheres

A facile method of preparing hierarchical hollow silica microspheres containing surface silica nanoparticles (HHSMs) through the sol-gel process of tetraethylorthosilicate employing a quasi-hard template of non-cross-linking poly(4-vinylpyridine) microspheres is proposed. The quasi-hard template contains the inherent catalyst of the basic pyridine group, and a few of the polymer chains can escape from the template matrix into the aqueous phase, which initiates the sol-gel process spontaneously both on the surface of the template used to prepare the hollow silica shell and in the aqueous phase to produce the surface silica nanoparticles. By tuning the weight ratio of the silica precursor to the quasi-hard template, HHSMs with a size of about 180 nm and a shell thickness ranging from 14 to 32 nm and surface silica nanoparticles ranging from 17 to 36 nm are produced initially through the deposition of surface silica nanoparticles onto the silica shell, followed by template removal either by calcination or solvent extraction. The synthesized HHSMs are characterized, and a possible mechanism for the synthesis of HHSMs is proposed.     

电感耦合等离子体质谱法（ICP-MS）测定白砂糖中微量元素

目的 白砂糖是甘蔗糖业的主要产品,是人们日常生活中普遍食用的甜味剂.了解白砂糖中的微量元素营养成分,为健康吃糖提供科学依据.方法 采用硝酸和高氯酸消解法处理样品,用电感耦合等离子体质谱法（ICP-MS）测定白砂糖中的微量元素.结果 14种微量元素的检出限为0.336 1～11.63 μg·L-1,方法的准确度为95.0％～110.0％,方法精密度为1.30％～5.32％.结论 方法简便、快速、准确,可作为白砂糖中微量元素含量常规的测定方法.     

Modelling and well-posedness of a nonlinear hybrid system in fed-batch production of 1,3-propanediol with open loop glycerol input and pH logic control

A fed-batch fermentation of glycerol by Klebsiella pneumoniae with open loop substrate input and pH logic control is considered in this paper. We propose a nonlinear hybrid system to describe this process, which consists of discrete variables to represent the flow rate of glycerol and alkali and continuous variables for substance concentrations. The hybrid system includes both time- and state-based switchings, which are respectively determined by a pre-assigned times sequence and an output equation of the pH. It is proved that the hybrid system is non-Zeno. Some basic properties of solutions to the hybrid system are also explored, including existence, uniqueness, boundedness and continuous dependence on initial state and parameters. Additionally, a numerical simulation is carried out to show that the proposed hybrid system can describe the fed-batch culture properly.     

A face recognition algorithm based on collaborative representation

In this paper, we propose a face recognition algorithm by incorporating a neighbor matrix into the objective function of sparse coding. We first calculate the neighbor matrix between the test sample and each training sample by using the revised reconstruction error of each class. Specifically, the revised reconstruction error (RRE) of each class is the division of the l₂-norm of reconstruction error to the l₂-norm of reconstruction coefficients, which can be used to increase the discrimination information for classification. Then we use the neighbor matrix and all the training samples to linearly represent the test sample. Thus, our algorithm can preserve locality and similarity information of sparse coding. The experimental results show that our algorithm achieves better performance than four previous algorithms on three face databases.