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251.
Stefan Gara Herbert Hutter Gerhard Stingeder Chunsheng Tian Herbert Führer Manfred Grasserbauer 《Mikrochimica acta》1992,107(3-6):149-160
This paper presents a three-dimensional characterization of oxygen defects in Czochralski-silicon (CZ) by 3D-SIMS using a camera based imaging system. Different manufacturing processes yielding a variation in size and distribution of oxygen precipitates are monitored by imaging SIMS and conventional depth profiling. Emphasis is laid on the characterization of the precipitation behavior governed by different annealing processes. The limitations of 3D SIMS for oxygen defect imaging are studied. Sputter induced microroughening of the crater bottom, investigated by SEM, is shown to be strongly correlated with defect densities caused by oxygen precipitates. 相似文献
252.
A CMOS Hearing Aid Device 总被引:1,自引:0,他引:1
Jose′ Silva-Marti′nez Sergio Soli′s-Bustos Jorge Salcedo-Suner Rogelio Rojas-Herna′ndez Martin Schellenberg 《Analog Integrated Circuits and Signal Processing》1999,21(2):163-172
In this paper a CMOS Hearing Aid Device is described. The system is composed of a low-distortion low-noise preamplifier, an automatic gain control (AGC), a fully programmable switched-capacitor filter (equalizer), and a control system. The device has been fabricated in a 1.2 m CMOS analog process. The dynamic range of the device is 55 dB while the harmonic distortion components are below –50 dB. Experimental results show the feasibility of the proposed architecture. 相似文献
253.
V.?E.?ArkhipovEmail author A.?V.?Gusel′nikov K.?M.?Popov P.?N.?Gevko Yu.?V.?Fedoseeva D.?A.?Smirnov L.?G.?Bulusheva A.?V.?Okotrub 《Journal of Structural Chemistry》2018,59(4):759-765
Graphene films on copper foils were synthesized using low-pressure (2200-2800 Pa) chemical vapor deposition (CVD) from methane/hydrogen mixtures. The number of graphene layers is shown to be dependent on the composition of gas mixture and synthesis parameters. The annealing procedure of copper foils used as substrates was optimized to obtain high quality graphene. Atomic and electronic structures of graphene on copper and SiO2/Si substrates were studied by Raman, X-ray photoelectron, and near-edge X-ray absorption fine structure spectroscopy methods. 相似文献
254.
Marina Russo Katia Arena Domenica Mangraviti Laura de Gara Paola Dugo 《Natural product research》2020,34(1):39-45
AbstractPunica granatum L., commonly known as pomegranate, is an ancient fruit widely consumed all over the world as fresh fruit or juice. In addition, it is extensively used in therapeutic formulas, cosmetics and food seasonings. The fruit is native to Afghanistan, Iran, China and the Indian sub-continent. The pomegranate market has steadily grown, presumably due to the increasing demand of health-conscious consumers for products with potential beneficial effects on human health, due to the synergistic presence of a unique and complex phytochemical composition that enclose anthocyanins, phenolic acids and hydrolysable tannins. Conventionally, for their analysis liquid chromatography is employed even though it can present some drawbacks in terms of resolving power. In this contribution, as a valuable alternative, comprehensive two-dimensional liquid chromatography with “shifted gradients” in the second dimension, was applied for the characterization of three pomegranate samples, leading to the identification of 37 different polyphenolic compounds. 相似文献
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257.
在纳秒激光脉冲辐照下,随着CCD探测器损伤程度的加深,成像系统输出画面中先后出现点损伤、白线损伤以及完全失效等现象,且损伤阈值呈现出概率分布特性。实验激光波长为1 064 nm,首先采用n-on-1辐照模式,研究CCD探测器在不同损伤程度下的损伤现象,从器件工作原理的角度分析各种现象出现的机理。利用光学显微镜观察样品的损伤形貌,发现探测器的损伤部位从内部材料开始,逐渐发展到位于表面的微透镜结构。接下来,采用1-on-1辐照模式测量了点损伤和完全失效阶段的激光能量密度阈值,并以损伤概率的形式进行描述,得到实验样品的完全失效阈值在100 mJ/cm2左右。 相似文献
258.
A.?A.?Vasil′evEmail author I.?M.?Aladzheva O.?V.?Bykhovskaya 《Russian Chemical Bulletin》2017,66(4):661-665
The Tsuji—Trost allylation of CH acids, in particular, those of the YCH2CO2Et type (Y = CO2Et, C(O)Me, CN), with allylic acetates in the K2CO3—DMF system in the presence of palladium catalysts with ligands RN(PPh2)2 (R = Ph, Pri, c-C6H11) is accomplished. 相似文献
259.
在Goetschel-Voxman所定义的序关系下,首先讨论了模糊值函数的凸性,得到了凸模糊值函数的若干充分条件,并证明了凸模糊值函数的Jensen不等式;其次,讨论了凸模糊值函数的次可微性,给出了次微分的若干重要性质,并得到了次可微条件下取得最优解的充分必要条件以及若干个次可微的充分条件. 相似文献
260.
In this present article the topological of the solution ser for abstract Volterra equations is studied both in Banach spaces and in Fréchet spaces. It is shown that the solution set for certain nonlinear abstract Volterra equations in the Fréchet spaces C[0,∞) and Lp loc[0,∞) (l≤p≤∞) are Rδ sets. Applications of the main results to nonlinear classical integral equations are given 相似文献