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51.
Jifeng Gao Jinping Suo 《Applied Surface Science》2011,257(22):9643-9648
To increase the SiC content in Cr-based coatings, Cr-Al2O3/SiC composite coatings were plated in Cr(VI) baths which contained Al2O3-coated SiC powders. The Al2O3-coated SiC composite particles were synthesized by calcining the precursor prepared by heterogeneous deposition method. The transmission electron microscopy analysis of the particles showed that the nano-SiC particle was packaged by alumina. The zeta potential of the particles collected from the bath was up to +23 mV, a favorable condition for the co-deposition of the particles and chromium. Pulse current was used during the electrodeposition. Scanning Electron Microscopy (SEM) indicated that the coating was compact and combined well with the substrate. Energy dispersive X-ray analysis of Cr-Al2O3/SiC coatings demonstrated that the concentration of SiC in the coating reached about 2.5 wt.%. The corrosion behavior of the composite coating was studied by potentiodynamic polarization and electrochemical impedance spectroscopy techniques. The data obtained suggested that the Al2O3/SiC particles significantly enhanced the corrosion resistance of the composite coating in 0.05 M HCl solution. 相似文献
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本文以BGA和PLMP两种封装为例,介绍了仙童半导体公司的新型封装。并与标准封装在电气性能和热性能方面进行了比较。同时给出了核心DCDC变换器的设计方法,并给出了实验结果。 相似文献
54.
Brad Armendt 《Acta Analytica》2008,23(1):29-43
What can rational deliberation indicate about belief? Belief clearly influences deliberation. The principle that rational belief is stake-invariant rules out at least one way that deliberation might influence belief. The principle is widely, if implicitly, held in work on the epistemology of categorical belief, and it is built into the model of choice-guiding degrees of belief that comes to us from Ramsey and de Finetti. Criticisms of subjective probabilism include challenges to the assumption of additive values (the package principle) employed by defenses of probabilism. But the value-interaction phenomena often cited in such challenges are excluded by stake-invariance. A comparison with treatments of categorical belief suggests that the appeal to stake-invariance is not ad hoc. Whether or not to model belief as stake-invariant is a question not settled here. 相似文献
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喷镀式电镀已广泛应用于圆片级封装(WLP)中,电镀杯是喷镀装置中最关键的部件,杯中的匀流板又是影响电镀质量关键。对匀流板的形状和位置进行了计算机模拟和优化,并实际应用于喷镀装置中,取得了很好结果。 相似文献
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A compact hand-held heated fluorometric instrument for performing real-time isothermal nucleic acid amplification and detection is described. The optoelectronic instrument combines a Printed Circuit Board/Micro Electro Mechanical Systems (PCB/MEMS) reaction detection/chamber containing an integrated resistive heater with attached miniature LED light source and photo-detector and a disposable glass waveguide capillary to enable a mini-fluorometer. The fluorometer is fabricated and assembled in planar geometry, rolled into a tubular format and packaged with custom control electronics to form the hand-held reactor. Positive or negative results for each reaction are displayed to the user using an LED interface. Reaction data is stored in FLASH memory for retrieval via an in-built USB connection. Operating on one disposable 3 V lithium battery >12, 60 min reactions can be performed. Maximum dimensions of the system are 150 mm (h) × 48 mm (d) × 40 mm (w), the total instrument weight (with battery) is 140 g. The system produces comparable results to laboratory instrumentation when performing a real-time nucleic acid sequence-based amplification (NASBA) reaction, and also displayed comparable precision, accuracy and resolution to laboratory-based real-time nucleic acid amplification instrumentation. A good linear response (R2 = 0.948) to fluorescein gradients ranging from 0.5 to 10 μM was also obtained from the instrument indicating that it may be utilized for other fluorometric assays. This instrument enables an inexpensive, compact approach to in-field genetic screening, providing results comparable to laboratory equipment with rapid user feedback as to the status of the reaction. 相似文献
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RonHuemoeller 《电子与封装》2005,5(3):19-22
在半导体整体的焊球阵列封装(BGA)领域,一份针对数个关键封装形式所进行的分析报告中,显示了造成不同焊球阵列封装形式成长或下跌的原因,并更清楚地点出了目前使用的数种基板技术的缺点。这篇分析报告列出了主要的焊球阵列封装的形式和基板发展潮流,还清楚地指出焊球阵列封装整体的发展延缓了硅芯片技术的演进,这在某些BGA领域中尤其明显,主要是因为缺乏先进的基板技术。因此文后得出结论,封装产业供货供应链基板市场中可能出现新的厂商,其也许来自主机板市场。 相似文献
60.
Ozgur Misman Mike DeVita Nozad Karim 《中国集成电路》2014,(12):77-81
由于具有高密度布线能力和相对合理的成本,在特殊用途集成电路(ASI Cs)的倒装封装中使用叠积层式(bui l d-up)有机基板非常受欢迎。典型的叠积层式基板包括核层和其双侧的高密度布线层(叠积层)。核层为封装提供所需刚度,其厚度可以是400μm,600μm,或800μm。新兴的无核基板技术去除了核层,可以提高布线密度,减薄封装,和获得更好的电气性能。本文比较了8层有核与无核基板在31mm和900锡球封装中的核心供电网络(PDN)的性能。在50MHz到2GHz频域内,我们用矢量网络分析仪测得两路高频S参数以分析相应的PDN。测量与模拟结果十分吻合。另外,我们还在时域内模拟计算了PDN对瞬变电流的响应。 相似文献