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81.
Grand canonical Monte Carlo (GCMC) simulations have been performed to investigate the components of the force between parallel charged surfaces in an electrolyte. The solvent primitive model (SPM) was used to investigate the effect of neutral hard sphere solvent particles on the force between the surfaces. The effects of particle size, wall charge density, charge valency of the electrolyte, and the exclusion of neutral hard sphere are discussed. When solvent particles are considered, the total force between the charged surfaces is always repulsive, even for divalent counterions. This is different from the earlier conclusion reached with a restricted primitive model electrolyte. The repulsive force decreases in going from monovalent counterions to divalent counterions.  相似文献   
82.
单秀玲 《中国科学A辑》2009,39(2):214-224
一个几乎广义平衡赛程设计NGBTD(k,m)是一个定义在km+1元集V上的(km+1,k,k-1)-BIBD,它的区组可按如下方法安排在一个m×(km+1)表阵中:(1)每列中所有区组构成V\{x}(x∈V)的一个部分平行类;(2)V中每个元素恰出现在每行的南个位置.完全解决了NGBTD(4,m)的存在性问题以及除4个可能例外值外的NGBTD(5,m)的存在性问题.  相似文献   
83.
In this article, we report on scanning tunneling microscopy (STM) observations of several different kinds of superlattice boundaries on highly-oriented pyrolytic graphite (HOPG) including an array of bead-like structures, a monolayer deep trench, a zig-zag shaped termination, and a plain boundary without features. Results of a simulation model show that a top rotated graphite layer with a straight boundary does not necessarily lead to the zig-zag shaped boundary of the resulting superlattice as has been previously claimed. The formation of the bead-like, trench, and zig-zag shaped boundaries is explained from the energetic point of view. Our study also shows evidence for the superlattice-mediated observation of a low-angle grain boundary with a varying tilt angle. A relationship between the periodicity of the boundary dislocations and the periodicity of the superlattice across the boundary is derived. The result of this work is important for an understanding of superlattices on graphite whose origin is not yet completely understood.  相似文献   
84.
The effects of the two photosensitizers chloroaluminum sulfonated phthalocyanine (ClAlSPc) and hematoporphyrin derivative (HpD) on the functional activities of macrophages and natural killer (NK) cells, two immunocyte populations implicated in the control of tumor development and spread, have been investigated. Murine peritoneal macrophages treated in vivo with ClAlSPc or HpD at 10 mg/kg body weight showed no impairment of Fc-mediated phagocytic capacity and only minor disturbances of in vitro tumoricidal/tumoristatic function. The NK cell activity of splenocytes obtained from photosensitizer-treated mice, assayed 24 or 48 h after i.v. injection of ClAlSPc or HpD at 10 mg/kg was unaffected compared to controls. However significant inhibition of NK activity was observed when splenocytes obtained from mice with or without subcutaneous Colo 26 tumors, treated with ClAlSPc plus laser therapy (675 nm) were used as effector cells. The results show that impairment of some anti-tumor activity can be observed in phthalocyanine treated or phthalocyanine + laser-treated animals but this relatively minor impairment may augur well for the use of systemic phthalocyanine administration in photodynamic therapy.  相似文献   
85.
磁共振成像(MRI)是一种无电离辐射的非介入性的眼内肿瘤检测方法,但分辨率和运动伪影是成像过程中不易克服的困难.以往的扫描方法或是不可避免的引入运动伪影,或是需要受试者做精确的配合,增加了成像的难度,给受试者带来不舒适的体验.本文提出了一种以超分辨率理论为基础的新的磁共振眼球成像方法,使用一种特制的眼球线圈,对眼部区域扫描一系列动态的图像,使得不同方向上的采集分辨率互补.最后经过预处理、配准、超分辨率重建等操作,得到高质量的磁共振眼球图像.实验结果表明,这种方法可以在不需要受试者做额外配合工作的情况下,得到更加清晰的磁共振眼球图像.  相似文献   
86.
磁控溅射淀积掺Er富Si氧化硅膜中Er3+ 1.54μm光致发光   总被引:6,自引:1,他引:5       下载免费PDF全文
用磁控溅射淀积不同富Si程度的掺Er富Si氧化硅薄膜.室温下测量其光致发光谱,观察到各谱中都含有1.54和1.38μm两个发光峰,其中1.54和1.38μm的光致发光峰分别来自Er3+和氧化硅中某种缺陷.系统研究了Er3+1.54μm光致发光峰强度对富Si程度及退火温度的依赖关系.还发现1.54μm发光峰强度与1.38μm发光峰强度相互关联,对此进行了讨论 关键词: Er 富Si氧化硅 光致发光 纳米硅  相似文献   
87.
Binuclear macrocyclic Robson-type complexes are of interest as models of biomolecules. Many of them have been prepared and widely studied since 1970s1,2. These complexes are restricted mainly to those metal ions that are employed as the template reagents, although Yunqi Tian et al. reported the proton-template synthesis of metal -free Robson-type macrocyclic ligands by addition of acid3 and Shaohua Gou et al. used Na+ as template4-6.Recently, in order to explore useful information concernin…  相似文献   
88.
The low-lying spectra of parabolic quantum dots with or without an impurity at the center are investigated.While it has been known that the electron-electron interaction leads to ground-state transitions on magic values of angular momentum in a magnetic field.We show,in this paper,that the implantation of an impurity ion at the center can either enhance or suppress such transitions,depending on whether it is an acceptor or a donor ion.  相似文献   
89.
借助具弱压缩的粘性逼近,提出一种新的修正的迭代算法,用以寻求一公共元,它既是一无穷族非扩张映像的公共不动点集中的点,也是一有限族的平衡问题的解集中的点,而且它还是一变分不等式的解.在适当的条件下,一些强收敛定理在Hilbert空间的框架下被建立.所得结果推广和改进了Colao等,Plubtieng 等,Colao等,Yao等及其他人的一些最新的结果.  相似文献   
90.
When a short pulsed, high power laser is focused on any solid target,a portion of the material is instantaneously exploded into its vapor. Laser ablation is a term to describe this explosive laser material interaction. Various processes like ejection of ions,atoms and clusters, thermal evaporation, plasma initiation and expansion, interaction between the plasma and the target, may result.  相似文献   
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