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91.
LM331是一种精密频率电压转换器。非常适用于用作模/数转换器。文中介绍了LM331的主要性能指标.同时给出了其与单片机8098的接口。 相似文献
92.
根据2450二辊轧机-2450四辊轧机轧制16Mn中厚板的开轧和终轧温度、二辊轧机和四辊轧机的压下量等主要工艺参数的测定值和钢板力学性能的测定值,利用统计回归分析所得的相关数学模型结合模糊聚类分析-模糊识别分析数学模型,建立了预测中厚板屈服强度σa和抗拉强度σb的相关数学模型,结果表明,16Mn钢中厚板材的屈服强度预测值和实测值的相对误差为2.9%~7.2%,抗拉强度σb的相对误差为0.1%~6.9%。 相似文献
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采用自制的相平衡研究装置,测定了PEG 4000-Cs2SO4-H2O三元体系在25,35和45℃时的等温平衡溶解度,同时给出了该体系的完整相图,在相图中观察到6个相区。结果表明,该体系双液相区随着温度的升高略有增加,结线的斜率也随温度的升高而增大。用四参数方程y=a bx^0.5 cχ dχ^2对该体系的双液线进行了拟合,拟合结果较好。用Othmer-Tobias方程和Bancroft方程对该体系结线的实验数据进行了关联,所有线性相关系数均大于0.98。热重分析确定平衡固相组成为无水硫酸铯。 相似文献
95.
为了有效地使用热处理强化变形铝合金制造各种结构材料和零部件。研究其焊接性能指标.以Al-Cu-Mn系铝合金(2A16)为对象,采用交流钨极氩弧焊焊接工艺及同质和异质焊丝,制备了2A16硬铝合金焊接试样.通过测试力学性能、金相组织和扫描电镜断口分析等方法,对其焊接性能进行了研究.结果表明:2A16硬铝合金有较好的抗结晶裂纹形成能力,影响其焊接性能的主要问题是过时效软化区的强度下降:当填充金属中Mg/Cu质量比比较大时,焊缝出现脆断倾向,欲进一步提高焊接接头强度,一方面可采用能量密度更高的热源,同时减小焊接线能量,以减少过时效软化区的不利影响;另一方面,限制填充金属中Mg/Cu的质量比,避免出现对焊接接头强化不利的β相和T相. 相似文献
96.
Structural and electrochemical properties of vanadium oxide thin films grown by d.c. and r.f. reactive sputtering at room temperature 总被引:7,自引:0,他引:7
Vanadium oxide thin films were grown at room temperature by direct current and radio-frequency reactive sputtering systems to compare the structural and electrochemical properties. Rutherford backscattering spectrometry and Fourier transform infrared measurements reveal that the composition of the as-deposited films consists of the V2O5 phase regardless of the deposition methods. Wide-angle X-ray diffraction measurements show that the crystallinity of the as-deposited V2O5 films is different depending on the deposition method. Films deposited by direct current reactive sputtering were amorphous, whereas films deposited by radio-frequency reactive sputtering were crystalline. Scanning electron microscopy measurements show that the V2O5 films grown by radio-frequency reactive sputtering had a large grain size but the films grown by direct current reactive sputtering were amorphous. Charge–discharge measurements taken at room temperature with a constant current clearly indicate that the films grown by direct current sputtering demonstrated typical amorphous behavior, whereas the V2O5 films grown by radio-frequency sputtering demonstrated the discharge behavior of crystalline V2O5. The origin of the structural and electrochemical properties of film grown by radio-frequency reactive sputtering is a self-bias effect. The self-bias effect induces ion bombardment during the growth of vanadium oxide thin film. These results suggest that direct current reactive sputtering is more desirable for growing amorphous V2O5 thin film than radio-frequency reactive sputtering. 相似文献
97.
Pt/V2O5/Al2O3 and Pt/Al2O3 monolithic catalysts were prepared by wet impregnation method, and the influence of V2 O5 addition on the catalytic activity for NO reduction by C3 H6 under lean burn condition was investigated in detail.The results show that Pt/V2O5/Al2O3 has better activity of NO reduction than Pt/Al2O3 , adding V2O5 to Pt catalyst makes the temperature window of NO reduction shift further to a lower temperature region.The activity of NO reduction decreases and there is a similar degree of deactivation over the two catalysts in the presence of SO2 in feed gas.Moreover, adding V2 O5 to Pt catalyst resulted in improvement of resistance to SO2 oxidation, which decreases the emission of sulfate particulate.Thermal aging treatment counteractes the promoting effect of V2O5 on NO reduction. 相似文献
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99.
《Journal of Nuclear Science and Technology》2013,50(12):709-718
Using the single-level and the Adler-Adler multi-level resonance formulas for 235U, whose parameters were derived by fitting to common experimental data, group constants were obtained for the energy region from 59.8 to 0.215 eV, having the same group structure as the 70 group JAERI-FAST set. It was found that use of the multi-level formula is preferable to the single-level alternative, the former being able to reproduce the experimental data more accurately than the latter. The resulting difference in the values of the group constants amounted to about 40% for some groups. The group constants of 233U, determined by means of multi-level formula are also presented for the energy region from 36.0 to 0.215 eV. 相似文献
100.