透明导电薄膜在不同衬底上的性能对比研究

为了对比研究不同透明衬底上ZnO:Al(ZAO)薄膜的性能,采用直流反应溅射法制备薄膜,并对其作EDS、XRD和电学测试分析.结果表明:所制备的ZAO薄膜具有典型的ZnO晶体结构;沉积在玻璃基片上的ZAO薄膜,Al,O含量高于沉积在透明聚酯塑料基片上的,而Zn的含量则相反;在两种衬底上获得的ZAO薄膜电阻率分别为4.5×10-4Ω*cm和9.73×10-4Ω*cm,可见光透射率分别达到87.7%和81.5%.由此可见:用直流反应磁控溅射法在不同衬底上都能获得可见光透射率达到80%以上的ZAO薄膜;相比而言,在玻璃衬底上获得的ZAO薄膜电阻率低,而在透明聚酯塑料上沉积的ZAO薄膜透射性好.     

LEC SI-GaAs中AB微缺陷和它对MESFET跨导性能的影响

用AB腐蚀液对SI GaAs晶片进行AB微缺陷显示 (AB微缺陷密度AB EPD :10 3～ 10 4 cm- 2 量级 ) ,用KOH腐蚀液显示位错 (位错密度EPD :10 4cm- 2 量级 ) ,发现衬底上的位错对器件跨导没有明显的影响 ,而用AB腐蚀液显示的AB微缺陷对器件性能及均匀性有明确的影响 :低AB EPD的片子跨导大 ;高AB EPD的片子跨导小。AB EPD有一临界值 ,当AB EPD高于此值时 ,跨导陡然下降。另外 ,还利用扫描光致发光光谱 (PLmapping)对衬底进行了测量 ,得出了与上述结果相符的结果。     

Scanning tunnelling microscopy of tobacco mosaic virus on evaporated and sputter-coated palladium/gold substrates

We present scanning tunnelling microscope (STM) images of untreated tobacco mosaic virus (TMV) deposited on thermally evaporated and on sputter-coated palladium/gold 40:60 (Pd/Au) substrates, and imaged under ordinary atmospheric conditions. The TMV imaged on both evaporated and sputter-coated substrates was consistently several times wider than the known diameter of the virus. TMV on evaporated Pd/Au became overcoated with Pd/Au material during sample preparation and appeared elevated in STM images, whereas TMV on sputter-coated Pd/Au appeared as depressions. When naked TMV were intentionally overcoated with Pd/Au, the STM images were found to be similar to those for TMV on evaporated Pd/Au.     

基于Ka波段分布式MEMS移相器芯片微封装研究

本文提出一种适用于Ka波段分布式MEMS移相器的新型封装结构——具有垂直互连线的薄硅作为分布式MEMS移相器衬底，并用芯片微封装方法对移相器进行封装。采用CST模拟软件研究封装结构对移相器射频性能影响，模拟结构表明：当封装结构衬底厚度、垂直互连线半径和空腔高度分别为450μm、50μm和80μm时，Ka波段分布式MEMS移相器的插入损耗小于0．55dB，回波损耗优于12dB，相移量具有很好的线性关系，说明该新型封装结构非常适合RFMEMS器件低成本批量封装。     

Potential for using enriched cultures and thermotolerant bacterial isolates for production of biohydrogen from oil palm sap and microbial community analysis

A limited number of bacteria can convert oil palm (Elaeis guineensis) sap to hydrogen with satisfactory yield and productivity. In this study, a total of 18 fermentative enriched cultures and 36 newly isolated thermotolerant bacterial strains were compared for hydrogen production from oil palm (OP) sap. The new isolates were obtained from hot springs, palm oil mill effluent and oil palm sap. The test was conducted in three steps: (i) a test for hydrogen production from mixed substrates (cellulose, starch, xylose, and glucose) and OP sap; (ii) a test for substrate concentration tolerance; and (iii) a test for thermotolerance. Five enriched candidates for each of the hydrogen producers were selected according to the criteria defined for the screening test. The hydrogen production of these selected bacterial strains from hot springs were cultivated in batch fermentation of oil palm sap at room temperature (30 ± 2 °C). Five enriched cultures, namely 81RN1, OPS, 85RN5, 89SR3-2 and 112YL1 were found to give high cumulative hydrogen formation of 1085, 1009, 994, 983 and 778 mL H₂/L-OP sap, respectively, with the hydrogen content of 29.8, 29.4, 28.7, 27.1 and 27.5%, respectively. PCR–DGGE profiling showed that all these five enriched cultures consisted of species closely related to the genus Clostridium sp. based on the 16S rRNA gene. For pure cultures, the top five hydrogen producers were the isolates encoded as PS-3, PS-4, PS-5, PS-7 and PS-8 exhibiting the hydrogen production of 1973, 1774, 1335, 1170 and 1070 mL H₂/L-OP sap, respectively, with the hydrogen content of 33.7, 29.6, 32.5, 31.5 and 26.4%, respectively. Identification of these high hydrogen producers using 16S rRNA sequence matching showed that the isolates PS-3 and PS-8 belonged to Clostridium beijerinckii, while the isolate PS-7 belonged to Clostridium acetobutylicum and the isolates PS-4 and PS-5 belonged to Klebsiella sp. and Klebsiella pneumoniae, respectively. Therefore, the pure culture C. beijerinckii PS-3 exhibited 1.8 folds higher hydrogen production (1973 mL H₂/L-OP sap) than the enriched cultures of 81RN1 (1085 mL H₂/L-OP sap).     

不同粘结剂对碳纳米管红外吸收涂层性能的影响

碳纳米管涂层已在低温工作环境中大量应用,所选用的粘结剂在很大程度上影响其红外吸收性能及与基体的结合性能。分别用水玻璃粘结剂和磷酸盐粘结剂与碳纳米管、镍粉混合制成涂料,并将其涂覆在铜基体表面。采用XRD和SEM对涂层的红外吸收性能、物相、晶体结构及形貌进行了表征;测试了涂层的抗热震性能。结果表明:当粘结剂为磷酸盐、含量为90%~85%时,1 400~3 570 cm~(-1)(2.80~7.14μm)波段内涂层的平均光吸收度达1.992~2.084,红外吸收性能最佳,抗热震次数可达35次(25~120℃),满足了用户要求(10次)。     

Improvement of adhesive bonding of grit-blasted steel substrates by using diluted resin as a primer

This study reveals the micro-structural details on the metal substrate surface prepared by grit blasting, and then proposes a simple resin pre-coating method aiming at full wetting of the substrate surface for stronger adhesive bonding. The resin pre-coating solution consisting of around 90% acetone and around 10% resin without hardener is used as a primer, which can be sprayed or blushed onto the grit-blasted metal substrate. The acetone solution can carry resin deep into micro-cavities created by grit blasting and effectively coat and wet micro-debris so that micro-voids or gaps between the adhesive joint and metal substrate can be removed. Since the resin pre-coating does not contain hardener and remains wet, the wettability of the substrate is also improved. The normal epoxy adhesive with hardener can then be applied onto the substrate surface. Despite having the primer-like function, the proposed resin pre-coating method still maintains the simplicity of one epoxy resin system. Based on the current study, a resin and acetone solution without hardener does not seem to have adverse effects on the final bonding strengths of adhesive joints, although acetone is known to have detrimental effects on resin and hardener adhesive systems. Four different surface conditions are examined, each having 14 specimens: (1) Grit-Blasted (GB) surface, (2) GB-surface with ultrasonic cleaning, (3) GB-surface with resin Pre-Coating (PC) only, and (4) GB-surface with both ultrasonic cleaning and PC. 25% improvement in the shear strength has been achieved by the resin pre-coating method, even without ultrasonic cleaning, in comparison with 8% improvement after ultrasonic cleaning. These results show GB-surface with PC is beneficial to adhesive bonding, which can be adopted for structural applications even if thorough substrate surface cleaning on site is not possible. The improved wettability of metal substrates after resin pre-coating contributes to the maximum possible utilization of the contact areas over the roughened substrate surfaces and thus leads to the enhanced adhesive bond strength.     

Physicochemical and sensory characteristics of soya protein isolate hydrolysates with added substrate‐like amino acids

Soya protein isolate (SPI) with or without added substrate‐like amino acid was subject to enzymatic hydrolysis catalysed by commercial proteases (Alcalase 2.4 L, flavourzyme and pancreatin). Addition of a small amount of amino acids (amino acid: SPI = 1: 2500, mol g^?1) during hydrolysis would cause a significantly (P < 0.05) reduced protein recovery, increased degree of hydrolysis, and altered amino acid composition and antioxidant activities of SPI hydrolysates. The SPI hydrolysates prepared with added Asp, Arg or Lys exhibited a higher antioxidant activity than the control. The bitterness of SPI hydrolysates was largely reduced upon addition of Met, Asp or Glu during hydrolysis, whilst the umami taste and mouthfeel‐liking were remarkably increased. Therefore, adding amino acid during hydrolysis is a feasible and beneficial approach to improve both the functional and sensory properties of SPI hydrolysate.     

金属渗透梯度层陶瓷基片在LED散热中的应用

在LED散热领域,铝基板居很大市场份额.介绍了金属渗透梯度层陶瓷基片,这种陶瓷基片由陶瓷与金属材料相互扩散形成的,导热性、绝缘性、抗剥离强度及抗震动性好,可解决大功率LED的散热问题.这种基板已用于制作大功率LED灯,并取得了明显的社会经济效益.