四丁基溴化铵水合物浆在蓄冷空调中的应用前景

TBAB水合物浆作为适用于空调工况的新型两相潜热输送载冷剂,可以大幅度降低冷量输送的功耗。通过添加成核剂的方法来降低所需的过冷度,制备方法简单节能,而且蓄冷特性出色,相变蓄冷温度与溶液的浓度密切相关,可通过调节溶液的浓度,获得与空调冷冻水一致的相变温度。根据非牛顿流体的特点,综述了国内外关于TBAB水合物浆流变方程的选择,列出了表观粘度及传热系数的计算方法,并指出TBAB水合物浆应用于蓄冷空调中的优点。     

冷蒸气原子吸收光谱法测定铜精矿中的汞

本文研究了一种用冷蒸气原子吸收光谱测定铜精矿中汞的方法。铜精矿用逆王水或硫酸-高锰酸钾(固)消化后用测汞仪测定其中的汞含量。测定结果的相对标准偏差小于5%;回收率在92-107%之间。     

InGaAsSb negative luminescent devices with built-in cavities emitting at 3.9 μm

An As₂S₃ fiber coupled to an InGaAsSb photodiode was used to record the radiation distribution over the emitting surface in InGaAsSb episide-down-bonded negative luminescence devices (λ=3.9 μm). Emission spectra were recorded under forward and reverse bias and both were modulated by a Fabry–Perot resonator formed by the anode contact and emitting InAs surface in 45-μm thick diodes. The results show that the current/emission distribution crowds in the vicinity of the contact under forward bias, while a uniform current/emission distribution over the emitting surface is seen under reverse bias.     

冷原子荧光法测定中药中的痕量汞

本文应用冷原子荧光法，采用HNO3－H2O2的湿法消解体系，建立了中药中痕量汞的测定方法。同时，对样品的前处理方法和仪器工作条件进行了探讨和优化。在选定的实验条件下，测得检出限为0.03μg/L，用国标物质桃叶验证结果与推荐值一致；用于实际样品的测定获得了满意的结果。     

Sequence comparison and environmental adaptation of a bacterial endonuclease

The periplasmic/extracellular bacterial enzyme endonuclease I was chosen as a model system to identify features that might be responsible for temperature- and salt adaptation. A statistical study of amino acid sequence properties belonging to endonuclease I enzymes from three mesophilic habitats (non-marine, brackish water and marine), and three marine temperature groups (psychrophile, intermediate and mesophile) has been conducted. Ten new endonuclease I genes have been sequenced in order to increase the sample size. A bioinformatical method of property dependent statistical analysis of alignments has been applied. To our knowledge this is the first time these methods have been used in order to investigate environmental adaptation of enzymes. Adaptation to low temperature seems to involve increased surface isoelectric point and hydrophobicity in contrast to salt adaptation in which the isoelectric point and hydrophobicity at the surface decreases. Redistribution of charge and hydrophobicity might be the most important signature for cold adaptation and salt adaptation of this enzyme class. The results indicate that general trends of adaptation are possible to elucidate from the amino acid sequences. Also in this paper a new scale of stratified B-factors, derived from the Protein Data Bank, is presented.     

Relationship between particle size and deformation in the cold spray process

The flattening of aluminum and copper particles cold sprayed onto ceramic surfaces has been described by an ellipsoidal function. The accuracy of this approximation was verified from particle dissections performed in a focused ion beam/scanning electron microscope (FIB/SEM). Flattening data were collected from SEM measurements. It was shown that aluminum particle deformation was limited below ∼5 μm, and copper deformation below ∼2 μm. Deceleration of the particles through the bow shock, strain rate hardening and thermal conduction were factors that contributed to the differences in deformation behaviour.     

Understanding the synthesis of DEGVE pulsed plasmas for application to ultra thin biocompatible interfaces

There is interest in the development of novel surface treatments for biocompatibility and non-fouling behaviors on various surfaces of in vivo devices. Polyethylene glycol thin films have shown promise as non-fouling passivation layers for such devices. Studies of the surface chemistry and non-fouling effectiveness of plasma deposited di(ethylene glycol) vinyl ether (DEGVE) films have observed that non-fouling performance is maximized when plasma deposition occurs at low values of average power, (<5 W). [Y.J. Wu, R.B. Timmons, J.S. Jen, Frank E. Molock, Non-fouling surfaces produced by gas phase pulsed plasma polymerization of an ultra low molecular weight ethylene oxide containing monomer, Colloids and Surfaces B: Biointerfaces 18 (2000) 235–248.] Chemical properties of plasma deposited films were directly attributed to the complex interactions occurring within the gas phase. In order to better understand the deposition process, as well as the significance of the conclusions drawn by Wu et al. [Y.J. Wu, R.B. Timmons, J.S. Jen, Frank E. Molock, Non-fouling surfaces produced by gas phase pulsed plasma polymerization of an ultra low molecular weight ethylene oxide containing monomer, Colloids and Surfaces B: Biointerfaces 18 (2000) 235–248.] an investigation of the gas phase behavior in DEGVE pulsed plasma discharges was performed. Infrared spectra were used to characterize the chemical composition and dissociative behavior of DEGVE plasmas across a range of average powers. This allowed for the construction of a dissociative model of the DEGVE monomer in the plasma discharge. Analysis of the observed dissociative pattern demonstrates the presence of key daughter species which would account for the observations made on deposited DEGVE films by Wu et al. [Y.J. Wu, R.B. Timmons, J.S. Jen, Frank E. Molock, Non-fouling surfaces produced by gas phase pulsed plasma polymerization of an ultra low molecular weight ethylene oxide containing monomer, Colloids and Surfaces B: Biointerfaces 18 (2000) 235–248.].     

金＠壳聚糖复合材料的合成、表征及其葡萄糖选择氧化性能

采用硼氢化钠化学还原氯金酸的碱性溶液制备了纳米金溶胶, 利用紫外-可见吸收光谱研究了金与壳聚糖的相互作用. 结果表明, 壳聚糖能够捕获金纳米粒子并易于形成金@壳聚糖复合材料. 利用X-光粉末衍射(XRD)、紫外-可见漫反射光谱(UV-vis DRS)、透射电镜(TEM)、红外光谱(IR)、微分热重及差热分析(DTG-DTA)等对这种复合材料进行了表征, 发现该材料具有较小的金纳米粒子, 壳聚糖的存在改变了金纳米粒子的等离子共振吸收, 二者之间存在一定的键合作用. 以分子氧为氧化剂, 在温和条件下, 该材料对葡萄糖选择氧化制葡萄糖酸反应具有良好的催化性能.     

Thermal behaviour of two room-temperature ionic liquids containing the methylimidazolium cation

We have investigated the glass transition relaxation of two room-temperature ionic liquids using Modulated Temperature Differential Scanning Calorimetry (MTDSC). Furthermore, conventional DSC was used to clarify their crystallisation behaviour. One of the liquids avoids crystallisation, while the other shows cold crystallisation. A step-by-step temperature scanning experimental procedure was used to analyse in detail the thermal behaviour of the latter in the crystallisation and melting temperature regions. The existence of polymorphism is discussed.