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采用共沉淀法制备了一系列Mn-Fe复合氧化物,研究了物质的量比和温度对气相砷、硒吸附的影响,考察了As2O3和SeO2双组分气体的同时吸附特性,对吸附产物中砷、硒的稳定性进行测定。结果表明,As2O3和SeO2在Mn-Fe复合氧化物表面的吸附量随Min含量增加呈先增大后减小的趋势,当Mn/Fe物质的量比为1:1时吸附量达到最大;两者的最佳吸附温度分别为750和600℃;双组分气体同时吸附时,两者存在竞争作用,Mn-Fe复合氧化物会优先吸附As2O3,SeO2的吸附受到抑制;此外,预吸附的SeO2会增强临近原子吸附活性,促进As2O3的吸附;吸附后的Mn-Fe复合氧化物浸出液中砷和硒的质量浓度均低于控制限值,在随粉煤灰进行资源化利用(如作为混凝土成分、水泥原料等)过程中不会产生二次污染。 相似文献
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基于模糊物元理论的小康社会指标体系综合评价模型 总被引:1,自引:0,他引:1
将熵值理论与模糊物元理论相结合,建立了基于熵权的模糊物元小康社会综合评价模型.利用该模型对江苏省13个城市2007年的小康水平状况进行评价,并与综合分析法的评价结果进行比较,结果显示二者基本上一致. 相似文献
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AlGaN/GaN high electron mobility transistors(HEMTs) were exposed to 1 MeV neutron irradiation at a neutron fluence of 1 × 10 15 cm 2.The dc characteristics of the devices,such as the drain saturation current and the maximum transconductance,decreased after neutron irradiation.The gate leakage currents increased obviously after neutron irradiation.However,the rf characteristics,such as the cut-off frequency and the maximum frequency,were hardly affected by neutron irradiation.The AlGaN/GaN heterojunctions have been employed for the better understanding of the degradation mechanism.It is shown in the Hall measurements and capacitance-voltage tests that the mobility and concentration of two-dimensional electron gas(2DEG) decreased after neutron irradiation.There was no evidence of the full-width at half-maximum of X-ray diffraction(XRD) rocking curve changing after irradiation,so the dislocation was not influenced by neutron irradiation.It is concluded that the point defects induced in AlGaN and GaN by neutron irradiation are the dominant mechanisms responsible for performance degradations of AlGaN/GaN HEMT devices. 相似文献
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Hot carrier degradation and a new lifetime prediction model in ultra-deep sub-micron pMOSFET
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The hot carrier effect (HCE) of an ultra-deep sub-micron p-channel metal-oxide semiconductor field-effect transistor (pMOSFET) is investigated in this paper. Experiments indicate that the generation of positively charged interface states is the predominant mechanism in the case of the ultra-deep sub-micron pMOSFET. The relation of the pMOSFET hot carrier degradation to stress time (t), channel width (W ), channel length (L), and stress voltage (Vd ) is then discussed. Based on the relation, a lifetime prediction model is proposed, which can predict the lifetime of the ultra-deep sub-micron pMOSFET accurately and reflect the influence of the factors on hot carrier degradation directly. 相似文献
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为了探索回购契约对闭环供应链系统的动态影响,构建了基于回购契约的闭环供应链系统动力学模型,在不同回购契约参数条件下进行仿真,系统地分析了闭环供应链整体及各节点企业的利润变动情况.研究表明:1)上游成员承诺的回购率越高,闭环供应链整体及各节点企业的利润越大.2)在闭环供应链中,制造商所需的协调时间最长,销售商利润最大,回收商利润最小,但随着回购率增加至阈值后,回收商的利润增长率最高. 相似文献
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基于密度泛函理论的第一性原理和平板模型构造了最稳定的O2/CaO(001)表面,通过优化Se和SeO2在此表面可能的初始吸附结构得到最佳吸附构型,分析了Se原子在O2/CaO(001)表面向SeO2的转化。结果表明,Se原子在O2/CaO(001)表面的稳定吸附构型主要有两种,即O-Se-O和O-O-Se基团,其中,O-O-Se基团的Se终端具有一定化学活性;Se在O2/CaO(001)表面向SeO2转化所需反应能垒小于均相条件下生成SeO2所需反应能垒,表明CaO不仅作为吸附剂,也能促进Se向SeO2的转化;SeO2分子在O2/CaO(001)表面发生化学吸附时,吸附基底的部分价电子转移至SeO2分子轨道中。 相似文献