盐酸重量法测定高耐磨镍铜合金中硅含量

本文研究了高耐磨镍铜合金（NCu30—4—2—1）中硅的重量法测定条件。本法以盐酸冒烟使硅完全沉淀析出，过滤、灼烧、称重，再以HF挥发除去沉淀中的硅，灼烧、称重，从两次重量的差值求得纯净SiO2含量，计算得出样品中Si的含量。方法准确、实用，加标回收率在98％以上。     

钢、钛基材上火焰喷焊Ni基耐磨覆层的比较

本文分别在钢（45碳素钢、1Cr18Ni9Ti不锈钢）和钛（Ti6A14V钛合金）基材上实施了NiCrBSi粉末的火焰喷焊，用SEM-EDAX和XRD研究了覆层的元素分布、界面相和表层相组成。结果表明：钢基材与覆层之间几乎没有发生元素扩散，基材元素扩散到覆层中的距离不到30μm，而钛基材与覆层之间发生了剧烈的元素扩散，基材元素扩散到覆层表层（距离约1mm）。钛基材与覆层之间的界面上生成大量的低熔点物相NiTi2，而扩散到覆层表层的钛元素改变了表层的相组成，增加了表层的非平衡度和硬度。基于相图对导致覆层出现巨大差异的机理进行了讨论。     

A study of the dissipative properties of homogeneous materials deposited as coatings. Part 1. Method for the determination of the amplitude dependence of the true vibration decrement of the coating material

A method is proposed for the determination of the amplitude dependence of the true vibration decrement of homogeneous materials deposited as coatings on a substrate of rectangular cross section. The method is based on the self-consistent calculation of energy loss factors for the substrate and coating materials using experimental amplitude dependences of vibration decrement for coated substrate, obtained under the conditions of cantilever specimens of rectangular cross section. The applicability of the method is illustrated by the determination of values of the true vibration decrement of Co-20 wt.% Fe alloy deposited as a coating on VT1-0 titanium alloy. __________ Translated from Problemy Prochnosti, No. 6, pp. 134–143, November–December, 2007.     

Hydrogenation of HgCdTe epilayers on Si substrates using glow discharge plasma

Preliminary results of a study of the hydrogenation of HgCdTe epilayers grown by molecular beam epitaxy on Si substrates using a glow-discharge plasma are presented. The aim of the program is to employ H to passivate the detrimental opto-electronic effects of threading dislocations present in the HgCdTe epilayers. Secondary ion mass spectroscopy depth profiling has been performed to characterize ¹H and ²H incorporation. It has been found that H can be controllably incorporated in HgCdTe epilayers to levels in the 10¹⁴ cm⁻³ to 10¹⁸ cm⁻³ range while maintaining the sample at temperatures lower than 60°C. Profiles indicate that H accumulates in regions of known high defect density or in highly strained regions. Analysis of the H depth profile data indicates that the current density-time product is a good figure of merit to predict the H levels in the HgCdTe epilayer. There are progressive differences in the ¹H and ²H uptake efficiencies as a function of depth. Magneto-Hall measurements show consistently higher mobilities at low temperatures for majority carriers in hydrogenated samples.     

Conducting Flame-Sprayed Al Coatings on Textile Fabrics

Electrical conductive and flexible flame-sprayed Al coatings using powder and wire as raw material were successfully deposited onto diverse textile fabrics. The influences of the raw materials, spraying parameters, and fabric materials on the electrical conductivity and microstructure of the metal-fabric composites were investigated. A first series of experiments showed that a coating quantity higher than 20 mg/cm² is necessary for a very good surface conductivity. After the optimization of the spraying parameters, such as a reduced standoff distance and the use of a cooling setup, a high surface conductivity (∼500 S _A) was obtained, which is attributed to a better melting of the spray particles. The improvement in conductivity enables a reduction of the coating quantity, and therefore, the flexibility of the fabric materials is better conserved. This study showed that optimized electrically conductive composites onto flexible fabrics can be produced, without any preliminary thermal or chemical fabric specifications.     

Electrochemical deposition of black nickel solar absorber coatings on stainless steel AISI316L for thermal solar cells

We report the electrochemical deposition of nanostructured nickel-based solar absorber coatings on stainless steel AISI type 316L. A sol–gel silica-based antireflection coating, from TEOS, was also applied to the solar surface by the dip-coating method. We report our initial results and analyze the influence of the stainless steel substrate on the final total reflectance properties of the solar absorber. The relation between surface morphology, observed by SEM and AFM, the composition of the electrodeposited surfaces analyzed by X-ray powder diffraction and the study of different electrodeposition conditions and silica sol–gel coatings is described. The best solar absorptance and thermal emittance values obtained on stainless steel substrates were 0.91and 0.1, respectively.     

Kinetic data and substrate specificity of a keratinase from Chryseobacterium sp. strain kr6

BACKGROUND: Keratinases are important enzymes for biotechnological processes involving keratin hydrolysis. In this work substrate specificity and kinetic properties of a keratinase from Chryseobaterium sp. were investigated. RESULTS: The optimal conditions for activity of purified keratinase with respect to pH, temperature and sodium chloride concentration were established using factorial design and surface response techniques. The optimum conditions for keratinase activity were pH from 7.4 to 9.2, temperature from 35 °C to 50 °C and NaCl concentration from 50 to 340 mmol L^?1, having azocasein as substrate. Subsequently, the kinetic parameters for this substrate were determined to be K_m = 0.75 mg mL^?1 and V_max = 59.5 U min^?1. The K_i value for 1,10‐phenanthroline was estimated at 0.78 mmol L^?1. The enzyme specificity was evaluated over different synthetic and insoluble substrates. The protease exhibited specificity with selectivity for hydrophobic and positively charged residues. In relation to the insoluble substrates, the enzyme hydrolyzed preferably chicken nails. CONCLUSIONS: This enzyme effectively hydrolyzes insoluble keratin substrates. The knowledge of keratinase properties is an essential step in the development of biotechnological processes involving keratin hydrolysis. Copyright © 2008 Society of Chemical Industry     

梅林青霉Z18纤维素酶降解纤维素的研究

为增加纤维素的酶解反应速率,通过降解羧甲基纤维素钠、微晶纤维素、纤维素粉Sigmacell type50,研究梅林青霉(Penicillium Melinii Thom)Z18菌株纤维素酶的特性和作用条件.结果表明:纤维素底物浓度影响酶降解效率,纤维素浓度高于5%时,产生明显底物抑制,50~70℃和pH5.5是纤维素酶解最佳温度和酸碱度,酶解时间的延长有利于降解,但反应超过2 h,还原糖增加缓慢,K+和Mn2+能够增加纤维素酶降解羧甲基纤维素钠和纤维素粉Sigmacell type50效率,Fe2+和Cu2+对于所有纤维素酶解表现抑制,较低结晶度的羧甲基纤维素钠降解速率高于较高结晶度的纤维素粉,纤维素酶水解作用条件的优化和纤维素结晶度的降低能够提高纤维素酶的水解反应速率.     

双发光层白色FOLED的制备及其性能研究

采用以含ITO导电层的柔性透明PET基片作为衬底,荧光材料TBPe、Rubrene分别掺杂在主体材料CBP和Balq中作为蓝色发光层和橙红色发光层,制备了双发光层白色柔性有机电致发光器件(FOLED)。通过适当调节发光层的掺杂比例和厚度,得到了发光性能理想的白光器件。测量表明,制备的器件色稳定性很好,色度随外加驱动电压在很大范围内变化很小,且其色坐标均非常接近于白色等能点。当电流密度为50mA/cm2时,器件最高外量子效率达到0.9%。通过抗弯折性能的测试证明,可以基本实现柔性显示的目的。     

共溅射法制备ITO:Zr薄膜及其特性研究

采用ITO靶和Zr靶共溅射在玻璃衬底上沉积了ITO:Zr薄膜,研究了衬底温度、氧流量对ITO:Zr薄膜性能的影响.表征和对比了ITO:Zr薄膜晶体结构和表面粗糙度的变化ITO:Zr薄膜在低温生长时就可以得到良好的光电性能,衬底温度的提高显著改善了薄膜光电性能;一定范围的氧流量也可以改善薄膜的性能,但过量的氧却使得ITO:Zr薄膜的光性能变差.透射谱表明各参数的变化引起了明显的"Burstin Moss"效应.当优化溅射条件为工作气压0.5Pa、氧流量0.3 sccm、直流溅射功率45 W(ITO靶)和射频功率10 W(Z靶)、沉积速率8 nm/min和一定的衬底温度时,可以获得方阻10～20 Ω/sq和可见光透过率85%(含基底)以上的ITO:Zr薄膜.