High-rate deposition of amorphous and nanocomposite Ti-Si-C multifunctional coatings

Amorphous (a) and nanocomposite Ti-Si-C coatings were deposited at rates up to 16 μm/h by direct current magnetron sputtering from a Ti₃SiC₂ compound target, using an industrial pilot-plant system, onto high-speed steel, Si, and SiO₂ substrates as well as Ni-plated Cu cylinders, kept at a temperature of 200 or 270 °C. Electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction analyses showed that TiC/a-C/a-SiC nanocomposites were formed consisting of textured TiC nanocrystallites (nc) embedded in a matrix of a-C and a-SiC. Elastic recoil detection analysis showed that coatings deposited at a target-to-substrate distance of 2 cm and an Ar pressure of 10 mTorr have a composition close to that of the Ti₃SiC₂ compound target, as explained by ballistic transport of the species. Increased target-to-substrate distance from 2 cm to 8 cm resulted in a higher carbon-to-titanium ratio in the coatings than for the Ti₃SiC₂ compound target, due to different gas-phase scattering properties between the sputtered species. The coating microstructure could be modified from nanocrystalline to predominantly amorphous by changing the pressure and target-to-substrate conditions to 4 mTorr and 2 cm, respectively. A decreased pressure from 10 mTorr to 4 or 2 mTorr at a target-to-substrate distance of 2 cm decreased the deposition rate up to a factor of ~ 7 as explained by resputtering and an increase in the plasma sheath thickness. The coatings exhibited electrical resistivity in the range 160-800 μΩ cm, contact resistance down to 0.8 mΩ at a contact force of 40 N, and nanoindentation hardness in the range of 6-38 GPa.     

深天井钻机钻进导孔的工作参数研究

为了确保天井钻机在钻进导向孔时牙轮钻头处在岩石的有效体积破碎状态中工作,基于MATLAB软件,对大量深天井钻机钻进不同直径导向孔时的现场工作数据进行了分析和数据拟合,得出了天井钻机在最佳工作状态时的工作轴压、工作扭矩、钻进速度与牙轮钻头所在的掘进深度及普氏岩石硬度系数的数学模型,为设计先进的智能型大型深天井钻机全自动化导向孔钻进系统提供了理论依据。     

基于PLC与步进电机的装载机先导手柄阀测控系统开发

针对装载机先导手柄阀性能测试要求,开发了采用PLC与步进电机控制的测试工装,介绍该测试工装的结构、工作原理和控制要求。在此基础上,对其进行PLC和LabVIEW软件开发。实际应用表明:该测控系统可满足先导手柄阀测试要求,且系统运行良好、试验效率高、数据采集及处理可靠有效,可为产品出厂测试、设计及维护提供实验支持。     

Project,Design, and Use of a Pilot Plant for Nanocapsule Production

The aim of this study was to find the scale-up parameters necessary for the preparation of nanocapsules (NCs) for pharmaceutical purposes. Starting from the laboratory scale (0.06 L), we designed and assembled a pilot plant (2 L) to produce NCs with the so-called emulsification-diffusion technique. We wanted to check if classical tools adequate for the pharmaceutical industry and for industrial scale-up purposes according to well-known chemical engineering technique could be used to perform the NC preparation. Experiments were carried out by varying some operative parameters, such as the impeller speed, the agitation duration for the emulsion preparation, and the reagent concentrations. As expected, good accordance between the NC produced at the laboratory scale and at the pilot plant scale was obtained. We conclude that the pilot plant can be used to perform a scale-up study of the industrial production of NC.     

Development of solid base catalyst X/Y/MgO/γ-Al2O3 for optimization of preparation of biodiesel from Jatropha curcas L.seed oil

The preparation and regeneration conditions of the identified catalyst X/Y/MgO/γ-Al₂O₃ with high catalytic activity were studied and optimized. The biodiesel was prepared by transesterification of Jatropha curcas seed oil produced in Guizhou with methanol at its reflux temoerature in the presence of X/Y/MgO/γ-Al₂O₃. The pilot plant tests were carried out in a 100 L reaction vessel. Both average yield and fatty acid methyl esters (FAME) content reached more than 96.50% under the optimum reaction conditions of the pilot plant tests designed withan oil/methanol molar ratio of 1: 10, catalyst concentration of 1.00%, and reaction time of 3 h at reflux temperature. In addition, analysis shows that the quality of biodiesel meets the standard EN 14214. __________ Translated from Modern Chemical Industry, 2007, 27(Suppl. 2): 452–455 [译自: 现代化工]     

Effect of flow rate and lead/copper pipe sequence on lead release from service lines

A pilot experiment examined lead leaching from four representative configurations of service lines including: (1) 100% lead (Pb), (2) 100% copper (Cu), (3) 50% Pb upstream of 50% Cu, and (4) 50% Pb-downstream of 50% Cu using a range of flow rates. The cumulative mass of lead release indicated that a typical partial replacement configuration (50% lead downstream of copper) did not provide a net reduction in lead when compared to 100% lead pipe (85 mg for 50% Pb-downstream versus 83 mg for 100%-Pb) due to galvanic and deposition corrosion. The partially replaced service line configuration also had a much greater likelihood of producing water with "spikes" of lead particulates at higher flow rates, while tending to produce lower levels of lead at very low flow rates. After the first 214 days the galvanic current between copper and lead was only reduced by 34%, proving that galvanic impacts can be highly persistent even in water with optimized corrosion control by dosing of zinc orthophosphate. Finally, this experiment raises concern about the low flow rates used during some prior home sampling events, which may underestimate exposure to lead during normal water use, especially when galvanic Pb:Cu connections are present.     

Invisible Agency

Jeremy Till and Tatjana Schneider call for a redefinition of the architect away from the professional who is ostensibly involved in adding ‘more stuff to the world’. Looking beyond the business of matter or managing the impact of that matter on the environment, they explore ways that designers can use their intelligence and creativity to shift existing habits of consumption and patterns of behaviour. They highlight the work for four practices who are already operating in this field: 2012Architecten, 00/:, Arif Hasan and Morar de Outras Maneiras (MOM).     

沿海高层建筑内覆盖质量的优化方案和案例

高层建筑内手机用户的使用感知质量情况,一直是无线网络优化工作研究的课题。随着城市的建设的快速发展,一些沿海城市海景楼、海景酒店林立而起,沿海高层建筑周边的CDMA质量覆盖技术也形成了新的研究课题。主要介绍几种高层导频污染和弱覆盖问题解决的优化方案和案例,从中提炼CDMA无线优化提供参考经验。     

异频在室内覆盖中的应用

介绍了异频方案在室内覆盖中的应用,包括在异频覆盖情况下空闲切换的实现,伪导频的配置方式,并介绍了异频待机、室内异频分层覆盖的方案及相关案例。