Synthesis,hole mobility,and photovoltaic properties of two alternating poly[3‐(hex‐1‐enyl)thiophene‐co‐thiophene]s

Two alternating poly[3‐(hex‐1‐enyl)thiophene‐co‐thiophene]s, Pa (with 77% trans‐isomer and 23% cis‐isomer) and Pb (with 100% trans‐isomer), were synthesized by the coupling of 2,5‐dibromo‐3‐hex‐1‐enyl‐thiophene to 2,5‐bis(tributylstannyl)thiophene via a Stille reaction and compared with poly(3‐hexylthiophene‐co‐thiophene) ( P1 ) to study the effect of changing the carbon(α)–carbon(β) single bond into a carbon–carbon double bond on the properties of the polymers. From P1 to Pb and to Pa , the ultraviolet–visible absorption peaks of the polymers were slightly redshifted, and their electrochemical bandgaps decreased by 0.05–0.1 eV. X‐ray diffraction analysis indicated that Pa had a better lamellar structure than Pb . The hole mobilities of the three polymers, determined with the space‐charge‐limited current model, were 5.23 × 10^?6 ( P1 ), 2.34 × 10^?4 ( Pb ), and 7.02 × 10^?4 cm²/V s ( Pa ). The power conversion efficiencies (PCEs) of polymer solar cells based on the three polymers were 0.87 ( P1 ), 1.16 ( Pb ), and 1.70% ( Pa ). The increase in the hole mobility and PCE revealed the important effect of changing the carbon(α)–carbon(β) single bond into a carbon–carbon double bond on the properties of polythiophene derivatives containing 3‐alkylthiophene. The strategy used in this work enlarges the thinking to obtain novel, efficient donor polymers for optoelectronic applications. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 629–638, 2007     

CAD技术在电子封装中的应用及其发展

现代电子信息技术的发展,推动电子产品向多功能、高性能、高可靠性、小型化、低成本的方向发展,微电子封装、IC设计和IC制造共同构成IC产业的三大支柱。计算机辅助设计(CAD)作为一种重要的技术手段在IC产业中发挥了巨大作用,已广泛应用于电子封装领域。本文结合各个时期电子封装的特点,介绍了封装CAD技术的发展历程,并简要分析了今后发展趋势。     

沉积能量在气流介质中的热效应及其激光干涉法测量

从基本的气体动力学方程组出发分析了气流介质中由于放电、吸收激光等沉积能量所造成的热效应和气流的特性。对于典型的气流放电激光器条件,0.05≤M《0.2,气动方程有最简单的形式,很容易得到解析解,并可以用激光干涉法测量沉积能量和密度,温度和速度等气动参数沿流动方向的分布。     

Covering theorems of simplexes and systems of linear inequalities

A selection lemma for Ky Fan's coverings is first proved, and then applied together with Ky Fan's generalization of the classical Knaster-Kuratowski Mazurkiewicz theorem to obtain a new covering theorem of simplexes. As applications, results on the consistency for certain systems of linear inequalities are obtained.     

Error correction techniques for high-performance differential A/Dconverters

Error correction techniques that overcome several error mechanism that can affect the accuracy of charge-redistribution analog-to-digital converters (ADCs) are described. A correction circuit and a self-calibration algorithm are used to improve the common-mode rejection of the differential ADC. A modified technique is used to self-calibrate the capacitor ratio errors and obtain higher linearity. The residual error of the ADC due to capacitor voltage dependence is minimized using a quadratic voltage coefficient (QVC) self-calibration scheme. A dual-comparator topology with digital error correction circuitry is used to avoid errors due to comparator threshold hysteresis. A fully differential charge-redistribution ADC implemented with these techniques was fabricated in a 5-V 1-μm CMOS process using metal-to-polysilicide capacitors. The successive-approximation converter achieves 16-b accuracy with more than 90 dB of common-mode rejection while converting at a 200-kHz rate     

在线同位素分离器中空阴极靶离子源

本文描述兰州中国科学院近代物理研究所的在线同位素分离器中空气阴极靶离子源的设计原理、结构和特性。对Ar和Xe的调试结果。分离器的分辨本领达到700-1200。满足高分辨的要求。     

An efficient furan synthesis using heterogeneous catalysis

A wide variety of 3-alkyne-1,2-diols have been found to undergo exceptionally clean 5-endo-dig cyclisations followed by dehydration at ambient temperature to give the corresponding furans in essentially quantitative yields when exposed to 10 mol % of 10% w/w silver(I) nitrate absorbed on silica gel.     

Novel program versus disturb window characterization for split-gate flash cell

In this letter, a new methodology for program versus disturb window characterization on split gate flash cell is presented for the first time. The window can be graphically illustrated in V/sub wl/ (word-line)-V/sub ss/ (source) domain under a given program current. This method can help us understand quantitatively how the window shifts versus bias conditions and find the optimal program condition. The condition obtained by this method can have the largest tolerance for program bias variations. This methodology was successfully implemented in 0.18-/spl mu/m triple self-aligned (SA3) split-gate cell characterization to provide program condition for 32 M products.     

双结π环自发磁化的研究

研究了超导双结π环的自发磁化现象.讨论了双结π环可能发生自发磁化的条件，指出了自发磁化条件不仅与电感参数β有关，而且与两结临界电流之比有关.并通过分析自由能证明自发磁化是稳定的状态.最后给出了讨论结果和渐进行为. 关键词： 双结π环 自发磁化 自由能     

On the invariants of base changes of pencils of curves,I

The main purpose of this paper is to prove the nonnegativity of the basic invariants of base changes of a surface fibration, which is conjectured by Xiao Gang. For this purpose we obtain some new inequalities between the invariants of the singularities ofz ^d =f(x, y). This work is supported by the National Natural Science Foundation of China and by the Science Foundation of the University Doctoral Program of CNEC. This paper is corrected while the author is visiting Max-Planck-Institut für Mathematik in Bonn.