Phonon–replica transitions in InGaN/GaN quantum well structures

A side-bump feature in a photoluminescence (PL) spectrum of an InGaN compound was widely observed. With reasonable fitting to PL spectra with three Gaussian distributions, the temperature variations of the peak positions, integrated PL intensities, and peak widths of the main and first side peaks of three InGaN/GaN multiple quantum well samples with different nominal indium contents are shown and interpreted. The existence of the side peaks is attributed to phonon–replica transitions. The variations of the peak position separations and the decreasing trends of the first side peak widths beyond certain temperatures in those samples were explained with the requirement of phonon momentum condition for phonon–replica transitions. In the sample with 25% nominal indium content, the phonon–replica transition could become stronger than the direct transition of localized states.     

饱和恢复法人体核磁共振自旋—晶格弛豫时间成象方法

当前,在医学核磁共振成象领域内,临床上广泛采用的是近似的自旋密度象、T1-和T2-加权密度象。但是,由于人体的正常组织和肿瘤之间的密度差别不大,从质子密度象很难区分人体的正常组织与肿瘤,而肿瘤与人体正常组织之间的在弛豫时间T1、T2的数值上差别较大。另外,自七十年代以来,大量关于离体(in vitro)核磁共振弛豫时间测量的文献表明,肿瘤的核磁共振弛豫时间T1,T2值具有明显的规律性,从而利用核磁共振弛豫时间成象的方法,及人体正常组织、良性及恶性肿瘤的活体(in vivo)T1,T2数值的测量,将有助于实现肿瘤识别的定量方法。     

用时间-边界跟踪模型确定抗蚀剂显影后的轮廓分布

文章提出了时间一边界跟踪模型的定义,阐述了用该模型确定抗蚀剂显影后的轮廓分布的方法,并给出了模拟计算结果.     

Codiameters of 3‐connected 3‐domination critical graphs

A graph G is 3‐domination critical if its domination number γ is 3 and the addition of any edge decreases γ by 1. Let G be a 3‐connected 3‐domination critical graph of order n. In this paper, we show that there is a path of length at least n?2 between any two distinct vertices in G and the lower bound is sharp. © 2002 John Wiley & Sons, Inc. J Graph Theory 39: 76–85, 2002     

一种新的奇偶非线性相干态及其量子统计性质

定义了一种新的奇偶非线性相干态即算符B2[B=af(N)]的两个正交归一本征态,利用数值计算方法研究了它们的量子统计性质.结果表明,与通常的奇偶相干态不同,在参数|β|变化的某些范围内,只有偶非线性相干态可以存在压缩效应,而振幅平方压缩和反聚束效应在这两个态中均可以呈现 关键词： 新的奇偶非线性相干态 压缩 振幅平方压缩 反聚束效应     

全面成绩管理的初探

利用数量化方法,数字特征法,W ilcoxon顺序和检验法以及试卷分析的各种方法(试题难度,区分度,信度,效度等),定量地解决了影响学生成绩的主要因素,并引入全面管理方法,明显地改善了学生成绩,学生综合能力明显加强.     

Fabricating tunable nanoparticle density gradients with the contact printing based approach

Recently, the generation of spatial gradient nanoparticle assemblies has attracted much attention. Such assemblies can be intriguing templates for building novel molecular architectures, and be employed as a combinatorial tool for quick determination of interaction selectivity for nanoparticles. In this communication, we report on convenient contact printing based techniques for generating lateral gradients containing nanoparticles with tunable geometry, scale and steepness. In the first method, octadecyltrichlorosilane (OTS) gradient surfaces were generated via the contact printing approach, and then spaces un-occupied by OTS molecules were back-filled with an amine-terminated silane, which allows the grafting of nanoparticles that were surface functionalized with carboxylic acid. By varying the size and geometry of the stamp, different geometrical gradients were generated. In addition, by changing the stamping procedures, either well-defined stepwise gradients or continuous gradients can be achieved. Furthermore, the contact printing based technique can be utilized in combination with diffusion of the aminosilane molecules to directly create its gradient, and consequently a nanoparticle density gradient.     

A STUDY OF J-INTEGRAL OF THE ORTHOTROPIC COMPOSITE MATERIAL

ＡＳＴＵＤＹＯＦＪ－ＩＮＴＥＧＲＡＬＯＦＴＨＥＯＲＴＨＯＴＲＯＰＩＣＣＯＭＰＯＳＩＴＥＭＡＴＥＲＩＡＬＷａｎｇＡｉ－ｑｉｎ（王蔼勤）；ＦｅｎｇＢａｏ－ｌｉａｎ（冯宝莲）；ＹａｎｇＷｅｉ－ｙａｎｇ（杨维阳）（ＴａｉｙｕａｎＨｅａｖｙＭａｃｈｉｎｅｒｙ．...     

(NH4)2MoS4在活性炭上浸渍过程的研究:Ⅱ.干燥机理及模型

（ＮＨ＿４）＿２ＭｏＳ＿４在活性炭上浸渍过程的研究Ⅱ．干燥机理及模型秦慧芳，张成芳，陆岗，俞丰，朱子彬（华东理工大学无机化工研究所，上海２００２３７）２３７）关键词硫代钼酸铵，活性炭，干燥，钼分布，干燥模型负载型催化剂的活性组分在载体上的分布，受浸渍...     

溅射功率对多层膜质量的影响

用磁控溅射技术制备薄膜，用X射线衍射研究在基片和靶间距离固定的情况下不同的溅射功率对薄膜结构的影响。结果表明：过低的溅射功率下淀积的薄膜有畸变的X射线衍射特征峰，特征峰强度小，半峰全宽大。而比较高溅射功率得到的薄膜有比较尖锐的X射线衍射特征峰，强度高和半峰全宽非常窄。研究表明，X射线衍射特征峰强度小和半峰全宽大的薄膜结构疏松，而强度高和半峰全宽非常窄的薄膜结构致密。