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91.
文章介绍了一种深海剖面测量系统的总体和软硬件设计,并给出了试验数据。该深海剖面测量系统利用浮力调节来控制测量平台升降,升降测量平台搭载CTD传感器、海流计等测量仪器,在升降过程中完成长时间深海环境参数剖面测量,是一种低功耗、高效率的海洋观测系统。 相似文献
92.
叙述胀砂与缩孔、缩松的关系,说明提高砂型刚度对防止胀砂、缩孔、缩松的重要性。指出型砂强度和砂型的紧实程度是常温下影响湿砂型刚度的主要因素。对影响湿砂型浇注时的刚度的各种因素进行了分析。 相似文献
93.
Sheng-Qiang Fan Chang-Jiu Li Guan-Jun Yang Ling-Zi Zhang Jin-Cheng Gao Ying-Xin Xi 《Journal of Thermal Spray Technology》2007,16(5-6):893-897
Deposition of nanocrystalline TiO2 coating at low temperature is becoming more attractive due to the possibility for continuous roll production of the coating
for assembly lines of dye-sensitized solar cell (DSC) at a low cost. In this study, porous nano-TiO2 coating was deposited by vacuum cold spraying (VCS) at room temperature on a conducting glass substrate using commercial
P25 nanocrystalline TiO2 powder. The microstructure of TiO2 coating was characterized by field emission scanning electron microscopy (FESEM) and nitrogen adsorption test. A commercial
dye (N719) was adsorbed on the surface of TiO2 particles within the coating to assemble a DSC. The cell performance was evaluated by employing simulated solar light at
an intensity of 100 mW/cm2. The results showed that TiO2 coating was deposited by the agglomerates of nano-TiO2 powders. The Brunauer-Emmett-Teller (BET) test of the as-sprayed TiO2 coating yielded a porosity of 49% and an average pore size of 17 nm. The assembled solar cell yielded a short-circuit current
density of 7.3 mA/cm2 and an energy conversion efficiency of 2.4%. The test results indicate that VCS was a promising method to deposit nanocrystalline
TiO2 coatings at low temperature applied to DSCs.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
94.
95.
采用CO2 作为保护气体消除大熔深激光焊接低碳钢时易发生的气孔问题 ,并对比研究了CO2 和Ar气保护条件下 12mm厚低碳钢板激光焊缝的组织和韧性。焊接试验利用 4kWNd :YAG激光器 ,采用双面深熔焊的方法 ,焊接条件为 4kW激光功率和0 .3 ,0 .5m/min的焊接速度。冲击试验采用一种自行设计的带侧面缺口的三缺口冲击试样 ,以保证断裂全部发生在焊缝。结果表明 ,利用CO2 作保护气体焊接低碳钢板 ,可以有效消除大熔深激光焊接时的气孔问题 ,并获得比Ar气保护下硬度较低 ,冲击韧性高的焊缝。研究工作为解决大功率激光深熔焊时容易发生的气孔问题提供了一条有效途径 相似文献
96.
97.
Aside from its importance as a design parameter for thermal barrier coatings, measuring thermal conductivity of thermal sprayed
coatings itself provides a unique method to critically characterize the nature, quantity, and anisotropy of the defect morphologies
in these splat-based coatings. In this paper, the authors present a systematic assessment of thermal conductivity of wide
range using the flash diffusivity technique. For the case of plasma sprayed yttria-stabilized zirconia (YSZ), coatings obtained
from wide-ranging initial powder morphologies as well as those fabricated under different particle states were characterized.
Both in-plane and through-thickness properties were obtained. Other material systems that were considered include: metallic
alloys and semiconductors of interests. Issues such as reproducibility and reliability in measurements were also considered
and assessed. Finally, work in collaboration with the Oak Ridge National Laboratory (ORNL) for alternate approaches to characterization
of thermal conductivity as well as high-temperature measurements was performed.
This article was originally published inBuilding on 100 Years of Success, Proceedings of the 2006 International Thermal Spray Conference (Seattle, WA), May 15–18, 2006, B.R. Marple, M.M. Hyland, Y.-Ch. Lau, R.S. Lima, and J. Voyer, Ed., ASM International, Materials
Park, OH, 2006. 相似文献
98.
数控机床铣削等距型面轴的理论研究 总被引:1,自引:0,他引:1
提出了在数控机床上铣削等距型面轴的新方法。通过建立和分析等距曲面及其加工中有关问题的数学模型,得到了数控铣削等距型面轴时确定自适应步长的算法以及行距、残留高度等重要理论问题的计算公式,为等距型面轴数控加工的实验研究奠定了理论基础。 相似文献
99.
本文介绍了液压数控冲剪式C型钢成型机的PLC控制系统的设计、实现及应用,该系统工作可靠,使用方便,极大地提高了C型钢成型机的自动化程度及生产效率。 相似文献
100.
The effect of tempering on the magnetic Barkhausen noise (MBN) signal profile was studied in case-carburised EN36 steel using a range of magnetic excitation frequencies and a number of frequency ranges for analysis of the MBN signal. The MBN level generally increases with tempering due to coarsening of the microstructure. With higher values of excitation frequency, fEX, the MBN profile exhibits a single peak, but with low values of fEX, double peaks are observed. The MBN peak obtained with higher fEX was found to correlate well with hardness changes in a region, down to 100 μm below the surface. The analysis of the MBN signal produced with low fEX, in narrow frequency ranges selected by software frequency filtering, showed variations in the extent of changes in the relative height of the two MBN peaks in the profile. After taking into account the skin depth-frequency relation for the MBN signal, variations in the values of the two MBN peaks in different analysing frequency ranges were found to correlate well with hardness variations at different depths down to 425 μm below the surface. An empirical relationship has been established between the hardness-depth profile and the MBN measurements. 相似文献