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排序方式: 共有195条查询结果,搜索用时 15 毫秒
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Abstract First results of a new electrolytical conductivity cell are reported concerning the initial stage of the pore opening process during track etching in vitreous solids. On the basis of the soft mode (low-energy excitation) model for track etching, a distribution function for the number of perforated micropores as function of time is calculated by accounting for the radial etch rate as function of the effective pore radius. 相似文献
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Atomically Precise Transformations and Millimeter‐Scale Patterning of Nanoscale Assemblies by Ambient Electrospray Deposition
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Anirban Som Depanjan Sarkar Sisira Kanhirathingal Thalappil Pradeep 《Particle & Particle Systems Characterization》2017,34(7)
The performance of semiconductor devices can be fine‐tuned through chemical transformation of their nanostructured components. Such transformations are often carried out in controlled conditions. Herein, the use of electrospray deposition of metal ions from solutions in air is reported, to bring about chemical transformations across mm2‐sized areas of nanostructures. This is illustrated with monolayer assemblies of ultrathin tellurium nanowires (NWs). The process does not require any reducing agent and can transform the NWs chemically, in the solid state itself, under ambient conditions. By using suitable masks, the beam of ions can be patterned to localize such transformations with nanometer precision to obtain aligned multiphasic NWs, containing atomically precise phase boundaries. By controlling the time of exposure of the spray, the scope of the process is further expanded to produce tellurium‐metal telluride core–shell NWs. The method described here represents a crucial step for ambient processing of nanostructured components, useful for applications such as semiconductor device fabrication. 相似文献
75.
对化学实验进行不断改进和创新,实验才能充满生命和活力,保持其在化学教学中的独特地位。从化学反应原理的模拟、化学实验的深化与完善、化学实验的创新、化学实验中非专业仪器的合理使用等4个方面对高中的30个实验进行了不同程度的改进和创新。 相似文献
76.
A composite ceramic coating containing Al2O3–ZrO2–Y2O3 was successfully prepared on AZ91D magnesium alloy by plasma electrolytic oxidation (PEO) technique in an alkaline aluminate electrolyte. The morphology, elemental and phase composition, corrosion behavior and thermal stability of the uncoated and coated samples were studied by environmental scanning electron microscopy (ESEM), energy dispersive X-ray spectrometer (EDS), X-ray diffractometer (XRD), electrochemical corrosion test, high temperature oxidation test and thermal shock test. The results showed that the composite ceramic coating was composed of Al2O3, c-ZrO2, t-ZrO2, Y2O3 and some magnesium compounds, such as MgO, MgF2 and MgAl2O4. After PEO treatment, the corrosion potential of AZ91D alloy was increased and the corrosion current density was significantly reduced. Besides, the coated magnesium alloys also showed excellent high temperature oxidation resistance and thermal shock resistance at 500 °C environment. 相似文献
77.
Characteristics of sealed plasma electrolytic oxidation coatings with electrochemical impedance spectroscopy
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<正>Plasma electrolytic oxidation(PEO) coatings are prepared on aluminium with graphite powders added into the electrolyte.The scanning electron microscopy(SEM) coupled with an energy dispersive x-ray analysis system(EDX) is used to characterize the surface and the cross-section morphologies of the coatings.The electrochemical impedance spectroscopy(EIS) is used not only to evaluate the corrosion resistance but also to analyse the structure of the coating. Results show that graphite powders are embedded in the PEO coating.The corrosion resistances of both the inner barrier and the outer porous layer are greatly improved,and the EIS could give some valuable detailed information about the coating structure. 相似文献
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熔融制样X射线荧光光谱法测定电解锰中锰、硅、磷和铁含量。用熔融后的四硼酸锂制作铂金坩埚保护层,以BaO2做氧化剂,在马弗炉内通过逐渐升温来氧化电解锰,然后熔融制取玻璃熔片,用X射线荧光(XRF)光谱法分析电解锰中锰、硅、磷和铁含量。锰、硅、磷和铁的相对标准偏差RSD分别为0.23%、2.82%、0.31%和0.53%。与其它分析方法比较,其结果更稳定。有效消除了电解锰熔融制样过程中的坩埚腐蚀问题,分析误差可完全控制在国家相关标准允许的范围内,实现了电解锰中各元素的快速准确测定。 相似文献
80.
溶液电导率的绝对测量方法 总被引:2,自引:0,他引:2
概括论述了三种溶液电导率绝对测量方法:基于精确测量电导池几何参数的测量方法、基于电容测量的溶液电导率测量方法和基于Van Der Pauw方法的溶液电导率测量方法。前一种方法用于许多国家的溶液电导率基准测量,后两种方法可发展为溶液电导率测量的基;住方法。 相似文献