Microtribological and electrochemical corrosion behaviors of polydopamine coating on APTS-SAM modified Si substrate

A polydopamine coating (coded as PDAc) was prepared successfully on a Si substrate through a two-step process. Briefly, to improve the adhesion of PDAc on the Si substrate, a self-assembled monolayer of 3-aminopropyl triethoxysilane (coded as APTS-SAM) was firstly generated on the bare Si wafer. Thereafter, the PDAc with different thickness was fabricated through the chemical adsorption and autopolymerization of the dopamine hydrochloride on the APTS-SAM coated Si substrate. The formation of PDAc on the APTS-SAM modified Si substrate was proved by the characterizations of contact angle measurement, attenuated total reflectance Fourier transform infrared (ATR-FTIR) analysis, and X-ray photoelectron spectroscope (XPS), etc. The ellipsometric thickness measurement and atomic force microscopy (AFM) image analysis showed that the PDAc became thicker and rougher with the deposition time prolongation. Microtribological study showed that the thickness and roughness of the PDAc played a significant role in the tribological properties. In comparison with the bare Si substrate, the PDAc with thinner thickness possessed lower friction and was anticipated to be used as protecting coating in the field of boundary lubrication. The electrochemical corrosion behaviors of the prepared PDAc were investigated using the electrochemical station and a low corrosion current density was revealed, implying that the PDAc had good anti-corrosion capability and might find potential applications in the field of corrosion resistance.     

激光偏振性对亚心形扁藻生物效应的影响

实验研究了偏振与非偏振激光对亚心形扁藻的促长作用、叶绿素含量以及色素粗提物吸收光谱等生物学效应的影响.采用488 nm,70 mW输出功率的氩激光,辐照哑心形扁藻,隔天取样进行细胞计数,培养至第6天提取叶绿素,测量叶绿素含量并扫描叶绿素的吸收光谱.实验结果表明,偏振激光与非偏振激光辐照对藻细胞密度、生长速率的促长作用区别不显著;偏振性与否对叶绿素含量的累积没有明显的区别;激光偏振性对色素粗提物的吸收光谱没有影响.激光偏振性与否均可对亚心形扁藻的生物效应产生有效的作用,激光偏振性与激光生物效应关系的研究有待于进一步深入.     

Finite-size effects in a D-dimensional ideal Fermi gas

By using the Euler-MacLaurin formula,this paper studies the thermodynamic properties of an ideal Fermi gas confined in a D-dimensional rectangular container.The general expressions of the thermodynamic quantities with the finite-size corrections are given explicitly and the effects of the size and shape of the container on the properties of the system are discussed.It is shown that the corrections of the thermodynamic quantities due to the finite-size effects are significant to be considered for the case of strong degeneracy but negligible for the case of weak degeneracy or non-degeneracy.It is important to find that some familiar conclusions under the thermodynamic limit are no longer valid for the finite-size systems and there are some novel characteristics resulting from the finite-size effects,such as the nonextensivity of the system,the anisotropy of the pressure,and so on.     

A macro traffic flow model with probability distribution function

In this paper, we introduce three probability distribution functions into the dynamic equation and propose a macro traffic flow model to investigate the impacts of the probability distribution functions on the evolutions of traffic flow under three typical states (i.e., uniform flow, shock, rarefaction wave, and small perturbation). The numerical results indicate that the probability distribution functions do not change the density and speed distributions of uniform flow, produce a two-layer shock but have no prominent effects on rarefaction wave, and have little effect on small perturbation.     

分布式光纤喇曼温度传感器的循环解调法

为了抑制温漂噪声积累,瑞利背向散射光窜扰反斯托克斯背向散射光,考虑了最近测量瑞利背散射光曲线解调反斯托克斯背向散射光温度曲线方法,即循环解调方法;该方法提高了系统的测温精度、稳定性,降低了系统的成本.实验结果与理论分析一致,系统的测温精度达±0.05℃.     

CFRP与角钢复合加固钢筋混凝土中长柱的受力分析

通过9根外包角钢与碳纤维布复合加固钢筋混凝土中长柱轴心受压试验,把复合加固柱核心混凝土分成有效约束区和弱约束区,研究了有效约束区和弱约束区混凝土的本构关系．在此基础上,把柱截面划分成若干计算单元,编制了全过程分析程序进行数值模拟计算．研究表明,计算结果与试验结果吻合较好,可为工程应用提供参考．     

中性金-钒-氧团簇氧化一氧化碳研究

本文实验制备了中性AuVO_(2～4)团簇并研究了其与CO和O_2的反应.实验结果表明,团簇AuVO_4和AuVO_3与CO反应主要生成吸附产物,而团簇AuO_2可与O_2反应生成AuVO_4.密度泛函理论计算结果表明,团簇AuVO_4和AuVO_3可在较高温度条件下氧化CO生成CO_2,从而形成催化氧化循环:AuVO_4+CO■AuVO_3+CO_2,AuVO_3+CO■AuVO_2+CO_2,AuVO_2+O_2→AuVO_4.     

Fast fabrication of a hybrid monolithic column containing cyclic and aliphatic hydrophobic ligands via photo‐initiated thiol‐ene polymerization

Three monomers, octakis (3‐mercaptopropyl) octasilsesquioxane, 1,2,4‐trivinylcyclohexane and isophytol were employed to synthesize a novel monolithic stationary phase via photo‐initiated thiol‐ene click polymerization for reversed‐phase liquid chromatography. Several factors such as porogenic system, reaction time and the molar ratio of functional groups were investigated in detail. The resulting poly(POSS‐co‐TVCH‐co‐isophytol) monolithic column exhibited suitable permeability for fast separation and outstanding thermal stability. Five alkylbenzenes were employed to evaluate the ability of chromatographic separation of the resulting monolithic columns at different flow rates, and showed the highest column efficiencies of 90,200–93,100 N/m (corresponding to 10.4–10.6 μm of plate height) at a velocity of 0.41 mm/s. The baseline separations of five anilines and eight phenols further proved the applicability of poly(POSS‐co‐TVCH‐co‐isophytol) monolithic column in the separation of small molecules.     

A tunable and reconfigurable microwave photonic filter based on a Raman fiber laser

A tunable and reconfigurable microwave photonic filter is demonstrated by employing a tunable Mach-Zehnder interferometer (MZI) and a wavelength-controllable Raman fiber laser. The free-spectral-range and spectral response of the microwave photonic filter are tuned and reconfigured by controlling the optical variable delay line in one arm of the MZI and the powers of the pump LDs. Experimental results are given to show the enhanced flexibility of the present microwave photonic filter.     

国际核能应用及其前景展望与我国核电的发展(续)

5 我国核电的发展 5．1我国核电已由起步进入发展阶段 我国是重视发展核电的，早在1956年制订的《国家原子能发展规划12年大纲》中就明确指出：“用原子能发电是动力发展的新纪元，是有远大前途的”，“在有条件下应用原子能发电，组成综合动力系统”．但是，在我国第一颗原子弹爆炸成功后，国家正拟起步核电之时，又逢文化大革命，受其干扰，致使我国核电起步较晚．1974年3月31日周恩来总理主持中央专门委员会，批准了30万千瓦级的压水堆核电方案，作为科技开发项目列入国家计划，核电才开始起步．这就是秦山核电站的由来．秦山核电站是第一座由我国自主创新建成的核电站，它于1983年基本完成研究开发和工程设计，1985年3月20日正式开工建设，1991年12月15日并网发电，结束了我国大陆无核电的历史，实现了我国核电技术的重大突破．我国从法国成套进口的两台90万千瓦级的核电机组也于1987年在广东大亚湾开工，两套机组分别于1993年和1994年并网发电．秦山核电站（见本期封底图）和大亚湾核电站（见本期封底图）的建成发电，为我国核电发展打下了良好的基础．