聚酰亚胺LB膜MIS结构C—V特性

本文报道了Ａｌ／ＬＢ聚酰亚胺膜／Ｐ－Ｓｉ（１００）ＭＩＳ结构的Ｃ－Ｖ特性研究结果。６７层ＬＢ膜样品Ｃ－Ｖ特性近乎理想，具有负的固定电荷密度约１０＾１＾１ｃｍ＾－＾２量级，平带时滞后小于０．３Ｖ，对于ＭＩＳ隧道结，除了在－０．５－１．５Ｖ间具有反型层箝位产生的电容峰外，在－１．５－４Ｖ间还出现了另一电容峰值，假设在强电场下隧穿能力剧增，从而结构由隧穿限制区重新进入半导体限制区，可以解释这一峰值的出现     

Studies on Langmuir-Blodgett multilayer formation from preformed poly(N-alkylacrylamides)

The spreading behaviour of preformed poly(N-alkylacrylamides) having hexyl (PHA), octyl (POA), decyl (PDA), dodecyl (PDDA), tetradecyl (PTDA), hexadecyl (PHDA), and octadecyl (PODA) substituents on a water surface, and the properties of the Langmuir-Blodgett (LB) films deposited from these polymer monolayers were investigated. The surface pressure (F)-area (A) isotherms of the polymer monolayers were changed by the chain length of the substituents and the subphase temperature. The optimum conditions for the formation of a stable condensed monolayer from the polymer series of similar molecular weight (c. 4 × 10³) were found when the alkyl substituent was the dodecyl group (i.e. PDDA) and the subphase temperature was 19°C. The condensed monolayers of PDA, PDDA, and PTDA could be transferred successively on to solid supports such as quartz slides, giving the Y-type uniform polymer LB films. The successive uniform depositions of PDDA monolayer up to 320 layers were confirmed by a relationship between the absorbance at around 200 nm due to carbonyl group and the number of layers deposited. The thickness of PDDA monolayer in the LB film was 1.72nm which agrees with the length of the dodecylamide substituent. F-A isotherms, FTIR, and X-ray diffraction measurements support that the polymer main chains are laid horizontally on the water surface and the alkyl substituents are oriented perpendicular to the chain in the condensed monolayer (see Scheme 1).     

大破口事故下事故容错燃料热工水力行为分析

事故容错燃料是事故应对能力更强的一种新型燃料,能够在较长时间内抵抗严重事故工况。本文基于TRACE程序考察了常规锆包壳与316SS、SiC、FeCrAl三种事故容错包壳材料在大功率压水堆破口事故下的PCT变化规律,并比较了三种材料对PCT的收益,计算结果表明SiC得到的收益略高为32 K。采用新型事故容错材料仅改变包壳材料即可得到PCT收益,对核电厂的安全性和经济性有重要意义,但随之而来的验收准则和引入的风险也会不同,还需要对此进行深入研究。     

有机及有机-无机复合热释电材料研究进展

热释电材料可用作红外探测器件、热摄像管等，在工业生产、国防科技以及日常生活中都有其特殊用途。本文从有机晶体热释电材料，聚合物类热释电材料，有机-无机复合材料和自组装与有序结构等方面概述了近年来有机及有机-无机复合热释电材料的研究进展。     

Effect of spreading solvents on Langmuir monolayers and Langmuir–Blodgett films of PS-b-P2VP

Langmuir monolayers of polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) diblock copolymers (with the same PS block length and different P2VP block lengths) formed at the air/water interface were characterized with the Langmuir film balance technique. Nonselective and selective solvents were used to spread the samples on the water surface and the spreading solvents showed large effect on the surface pressure–molecular area isotherms. The corresponding Langmuir–Blodgett (LB) films of the samples were characterized with atomic force microscopy. The LB films transferred from the Langmuir monolayers spread with a nonselective solvent only exhibited isolated circular micelles, while those with a selective solvent exhibited quite different morphologies including planar structure, rodlike structure, circular micelles, and labyrinth pattern. As far as we know, the labyrinth pattern appears in the LB films for the first time.     

LB技术制备ATO超薄膜

选用SnCl4·5H2O和SbCl3为基本原料，采用共沉淀法制得了掺锑氧化锡（ATO）沉淀，经胶溶制得ATO纳米水溶胶，将其溶于纯水并作为亚相，采用LB膜技术制备了10mm×30mmATO复合膜，烧结处理后制得ATO超薄膜，采用紫外光谱、X-射线衍射、原子力显微镜等手段对热处理前后的薄膜进行了形貌、组成、结构表征。结果表明，制得的是均匀性和覆盖度较高的ATO超薄膜。     

图像处理中的格子玻尔兹曼方法研究综述

目的 格子玻尔兹曼（LB）方法作为一种兼具建模与快速求解偏微分方程（PDE）功能的方法已被成功应用于图像去噪、修复和分割。考虑到国内外尚未有LB方法在图像处理中研究进展的综述论文,为使即将进入该研究领域的学者比较全面地了解该方法的研究现状,本文对其进行系统综述。方法 着重分析了与图像去噪、修复、分割和3维图像处理密切相关的文献,将LB图像处理模型的构建分为自上而下和自下而上两种途径,对图像处理中的LB模型从宏观和微观两个角度进行分类。对模型的计算机实现算法、算法时间复杂度以及模型的具体应用进行分析与总结。最后,讨论了LB方法与PDE方法的本质区别,并指出几个尚未解决的问题。结果 第一,LB方法在图像处理中具有清晰的物理意义,像素值可视被为粒子密度值,像素值的改变可被视为受松弛时间和源项影响的粒子的重新分布;第二,各向异性扩散模型、非线性扩撒模型、线性扩散模型之间的微观区别在于松弛时间的差异,以上模型的时间复杂度依次降低,含源项扩散模型的时间复杂度除松弛时间以外还受外力项的影响;第三,自上而下的建模方法仅仅将LB视为PDE的一种解法,自下而上的建模方法从LB方法的物理意义出发,直接设计演化方程的关键参数,相对于第一种方法更为灵活;第四,LB算法固有并行,编程简单,当该方法被应用于并行平台时,图像数据量越大,GPU/CPU加速比越明显;第五,各向异性、非线性扩散模型可用于图像去噪、修复,含源项扩散模型中外力项的设计对图像分割质量有较大影响。结论 尽管LB方法作为一种固有的并行算法在3维图像去噪、配准和分割等快速图像处理领域具有极高的应用价值,但仍然存在边界条件处理、并行平台选择及优化等几个值得继续研究的问题。     

Novel eddy current probes for pipes: Application in austenitic round-in-square profiles of ITER

Novel eddy current probes were developed to detect sub-millimetre defects with any orientation on the inner surface of pipes. Five different probes were designed, produced and experimentally validated. These probes include arrays of planar trapezoidal coils in a flexible substrate used alone or together with different winded drive coils. Numerical simulations with Finite Element Method were used to predict the probe response to defects with any orientation. Experimental results in austenitic steel jackets used in ITER revealed that the new probes have an improved reliability compared to conventional toroidal bobbin probes, allowing a higher sensitivity to circumferential defects.     

5,10,15,20-四-(4-N,N,N-二甲基十六烷基氨基苯基)卟啉LB膜结构的研究

研究了两亲性卟啉５,１０,１５,２０－四－（４－Ｎ,Ｎ,Ｎ－二甲基十六烷基氨基苯基）卟啉（ＴＤＭＣ１６ＰＰ）在气／液界面上的成膜性能,制备了其多层ＬＢ膜．用ＵＶ－Ｖｉｓ吸收光谱、荧光光谱、偏振ＵＶ－Ｖｉｓ吸收光谱和小角Ｘ射线衍射对ＬＢ膜进行了测试表征．结果表明：两亲性卟啉ＴＤＭＣ１６ＰＰ具有良好的成膜性能,其ＬＢ膜性质稳定,有较好的结构均匀性和周期性．在ＬＢ膜内,脂肪链并不是直立的,卟啉大环平面与基片平面成４２．５°排列．     

Investigation of the monolayer LB film properties of a silsesquioxane hybrid containing phenyl groups using SPM

In this study, we used a silsesquioxane hybrid material between phenyl group containing carbosilane dendrimer and siloxane polymer (G1-3Ph). As expected, G1-3Ph has a networked structure. Generally, it is difficult to generate uniform monolayers as common materials. However, if the materials have a networked structure, we can easily obtain uniform monolayers because of the molecular interactions. Moreover, this networked structure should have a cavity in which ions could be placed.We have fabricated Langmuir–Blodgett (LB) films of the G1-3Ph in a thin film state. We investigated the monolayer behavior using the π-A isotherm at the air–water interface. The π-A curves indicated that the surface pressure of this LB film from the liquid to the solid state falls between 5 and 8 mN/m. The monolayer was deposited onto highly oriented pyrolytic graphite (HOPG) substrates via Y-type deposition at a surface pressure of 5.5 mN/m. We also studied the morphological properties of the silsesquioxane hybrid LB films using SPM and determined the electrical properties of the LB films using STM. The I–V and the morphological characteristics of the sample were investigated at room temperature. The experimental results correlate with the calculated I–V curves when we use the parameters indicated in the caption. This study will enable us to apply a molecular electronic device to measure morphological and electrical characteristics on the nano scale.