高速钢钻头表面电火花制备TiN沉积层研究

以TA2为电极,在实际作业时,完全处在氩气的保护之下,通过电火花在W18Cr4V高速钢麻花钻头制备了Ti N沉积层。利用扫描电镜对钻头沉积层金相进行细致观察,在通过使用显微硬度计对涂层的硬度和厚度进行准确计量。在本文的研究中,通过比较干式切削条件下,对不同性质的钢材进行切削,发现沉积层头钻头和未沉积钻头在使用寿命和磨损程度方面,都存在比较大的差异。其对比发现,Ti N沉积层钻头在耐磨性和硬度等方面,要比未沉积钻头更具优势。

生长猪沉积N及尿N与吸收N的关系

为配合湖北白猪饲养标准化课题,研究蛋白质食入量对生长猪N沉积量的影响,以寻求较佳的N供给量及合理利用饲料蛋白质,故进行此试验。材料与方法时间 1984年5月与10月。地点华中农业大学试验猪场。试猪试验一为湖北白猪3系3世代第2胎生长猪;试验二为该猪3系4世代第1胎生长猪。体重均在30—40千克之间。设计与处理试验一以5种不同蛋白质食入量分为5组;试验二以同蛋白质食入量分为2组。均采用窝组配对分组,每组3头。

Electrodeposition of iridium from composite ionic liquid

In order to study the electrodeposition process of iridium in composite ionic liquid, the effects of N, N-dimethylacetamide（DMAC） on the viscosity, conductivity and electrochemical stability of composite ionic liquid BMIC-BMIBF4, as well as the electrochemical behavior of Ir Cl3 in this system were studied. Iridium（Ir） coatings were deposited at different constant potentials and characterized by SEM and XRD. The results show that the addition of DMAC can evidently decrease the viscosity of the composite system, increase conductivity and improve electrochemical stability of the composite system. Cyclic voltammograms of a Au electrode illustrate that the process controlled by diffusion rate is irreversible with the average charge transfer coefficient of 0.170 and average diffusion coefficient of 1.096×10-6 cm^2/s. In addition, SEM image shows that Ir film deposited at the reduction peak potential is dense and even, while XRD pattern shows that Ir deposit is polycrystalline structure.

Contribution of Atmospheric Nitrogen Compounds to N Deposition in a Broadleaf Forest of Southern China

A one-year study in a typical red soil region of southern China was conducted to determine atmospheric nitrogen (N) fluxes of typical N compounds (NH3, NH4-N, NO3-N, and NO2) and contribution of three sources (gas, rainwater, and particles) to N deposition. From July 2003 to June 2004, the total atmospheric N deposition was 70.7 kg N ha-1, with dry deposition accounting for 75% of the total deposition. Dry NH3 deposition accounted for 73% of the dry deposition and 55% of the total deposition. Moreover, NO2 contributed 11% of the dry deposition and 8% of the total deposition. Reduced N compounds (NH4+ and NH3) were the predominate contributors, accounting for 66% of the total deposition. Therefore, atmospheric N deposition should be considered when soil acidification and critical loads of atmospheric deposition on soils are estimated.

沉积物中酸可挥发性硫的测定方法的研究

沉积物的酸可挥发性硫的定量测定结合废水和土壤中硫化物的测定,采用分光光度法测定样品中的微量硫化物减小了人为的过失误差,酸可挥发性硫发生器代替半微量凯氏定氮装置作样品反应器,通过对处理酸度、反应温度、显色时间、标准溶液的最佳使用等条件的研究和改进,使用酸可挥发性硫发生器代替半微量凯氏定氮装置作样品反应器,在沉积物水溶液中加入乙酸锌为吸收液,对回收率、精密度及样品对比试验,回收率从50%～70%提高到90%以上,装置简单,便于应用。

Epitaxial n- and p-type Emitters for High Efficiency Solar Cell Concepts

Reducing the module prices by increasing the efficiency of solar cells is one of the major challenges in today＇s photovoltaic research. The emitter formation by epitaxial growth offers a cost-efficient and faster alternative to the standard furnace diffusion process. The efficiency potential of epitaxial emitters 〉 22% has already been proven using a single wafer, low pressure, chemical vapour deposition tool. The purpose of this work is to show the potential of epitaxially grown emitters by APCVD （atmospheric pressure chemical vapour deposition） compared to diffused emitters. The APCVD formation of epitaxial emitters at 1,050 ~C can be realised as high throughput inline process and only takes 1-2 min, whereas the diffusion process using POCI3 takes up to 60 min. Simulations show an increase in voltage of AVoc = ＋10 mV and a reduction in saturation current ,1o of 30% for the epitaxial emitter. The lifetime experiments of solar cells with epitaxial emitter exhibit a diffusion length Leff〉 750μm and an emitter saturation current of Joe 〈 50 fA/cm2 on a planar 10 Ω2cm p-type FZ wafer. Another important aim of this work is to evaluate the limitations of epitaxial emitters due to high thermal budget, interface recombination and the change of reflective properties on textured wafers due to the deposition process. Solar cell efficiencies up to 18.4% on p-type and 20.0% on n-type wafers presented in this paper underline that the emitter epitaxy by APCVD is a competitive process for the emitter formation.

Optimization of the thermoelectric properties of poly(nickel-ethylenetetrathiolate) synthesized via potentiostatic deposition

The coordination polymer poly（nickel-ethylenetetrathiolate） （poly（Ni-ett））, formed by nickel（Ⅱ） and 1,1,2,2-ethenetetrathiolate （ett）, is the most promising N-type organic thermoelectric material ever reported; it is synthesized via potentiostatic deposition, and the effect of different applied potentials on the optimal performance of the polymers is investigated. The optimal thermoelectric property ofpoly（Ni-ett） synthesized at 0.6 V is remarkably greater than that of the polymers synthesized at 1 and 1.6 V, exhibiting a maximum power factor of up to 131.6μW/mK2 at 360 K. Furthermore, the structure-property correlation ofpoly（Ni-ett） is also extensively investigated. X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS） analyses revealed that the larger size of crystalline domains and the higher oxidation state of poly（Ni-ett） synthesized at 0.6 V possibly results in the higher bulk mobility and carrier concentration in the polymer chains, respectively, accounting for the enhanced power factor.