元宝山露天矿矿床地质模型的构建及其可视化研究

本文紧紧围绕露天矿地质模型的建立及其显示这一主题,将矿床地质模型分为地质界面模型和矿床实体模型。用加权趋势面法对地质界面进行估值,生成地质界面的插值曲面;用边界多边形及断层对地质界面进行裁剪,形成地质界面的裁剪曲面;以地质界面的裁剪曲面和地表面的三角剖分面按空间组合成矿床实体模型。以元宝山露天煤矿为倒,实现了矿床模型的三维可视化。     

铝锂合金高速铣削表面完整性实验研究

铝锂合金密度低、比强度高、比刚度高等优良特性使得其成为新一代航空航天飞行器的主要结构材料.飞机蒙皮作为维持飞机外形的主要结构件,在飞机起飞降落过程中承受舱内外压差变化所引起的交变载荷作用,因此对于蒙皮结构零件的疲劳强度要求十分苛刻.零件的疲劳裂纹萌生往往是从表面的微观缺陷开始,并且表层以及亚表层的力学状态将影响裂纹萌生以及扩展速度.表面完整性包括表面的几何轮廓、显微硬度、金相组织、残余应力等,这些因素综合影响着零件的疲劳性能.与此同时,表面完整性表征参数与被加工材料属性、热处理状态以及加工工艺等具有密切的联系.研究了铝锂合金的机械铣削加工工艺对于其表面完整性的影响.传统蒙皮结构加工往往采用化学铣削的方法进行,占用厂房面积大,污染严重,废液处理费用高等,不符合现代可持续绿色制造的理念.目前对于铝锂合金的超塑成形工艺研究较多却鲜见有相关铝锂合金切削表面完整方面的相关研究.研究在干切情况与液氮冷却情况下切削三要素以及上一道滚压工艺对于表面完整性的影响,通过正交试验的方法全面考察了工艺参数对于表面形貌各个指标、表层亚表层金相组织以及残余应力的影响权重,并且验证了其显著性.比较了干切与液氮低温切削情况下表面形貌以及残余应力状态的异同点,验证了液氮冷却切削对于铝锂合金表面完整性提升的有效性,为提高铝锂合金疲劳性能提供了实验依据.     

钛合金及其表面处理的现状与展望

钛合金具有抗腐蚀能力强、比强度高、中温性能稳定等一系列优点，另一方面，它也有对粘着磨损和微动磨损非常敏感，耐磨性差，易氧化，对聚合物、金属及陶瓷涂层附着力差等缺点，这些缺点的存在限制了它的进一步应用，为克服钛合金这些缺点采取了一些相应的表面处理对策与手段，如表面微弧氧化、表面合金化、离子注入表面改性等。研究表明在钛合金表面形成TiC、TiN、TiO、(TiAl)N等纳米级，复合，渗、镀、注入层今后仍然是钛合金表面处理的发展方向。     

一种以特征线为中心的曲面特征表示方法

由于自由曲面特征形状复杂多样，难以有效地进行参数化表示．本文提出了一种以特征线为中心的曲面特征层次参数化的表示方法．该方法将特征线作为曲面构建的基本单元，将特征线划分为几何层、约束层、语法层和语义层，利用特征线信息对曲面特征进行参数分层，实现曲面特征的整体形状和局部形状的层次控制；在参数化表示上，按不同自由度分为半自由和完全自由曲面特征，并对曲面特征进行了统一的定义表示．实验结果表明，本文方法能够表达多种形状的自由曲面，在高层语义参数层面上方便地编辑曲面特征，是一种有效的曲面特征表示方法．     

磁盘表面形貌对润滑剂分布及磁头／磁盘之间润滑剂转移的影响

磁盘表层润滑剂在磁头与磁盘之间转移会影响磁头飞行的稳定性．本文采用改进后的粗粒珠簧模型,运用分子动力学方法,研究了磁盘上类金刚石薄膜（diamondlikecarbon,DLC）层粗糙度和磁盘表面凸起对润滑剂在磁盘表面分布及磁头／磁盘之间润滑剂转移的影响．研究结果表明,DLC层粗糙度对润滑膜平均厚度及磁盘表层粗糙度的影响很小;磁盘表面凸起对磁盘表层润滑剂分布的影响明显．类金刚石薄膜层的粗糙度和磁盘表层凸起均可增加转移到磁头上的润滑剂的体积．但磁盘表层粗糙度对磁头／磁盘之间润滑剂转移量的影响明显低于由磁盘表层凸起导致的磁头／磁盘之间润滑剂的转移量．     

2A70合金试件高速铣削表面粗糙度的试验模型

采用正交试验法,研究硬质合金球头铣刀在高速铣削2A70合金时,每齿进给量、切削深度、铣削速度和行距等铣削参数对试件表面粗糙度的影响、通过对试验数据的极差分析和方差分析,得出了影响零件表面粗糙度大小的主次因素,建立了2A70合金试件表面粗糙度的趋势模型,用于预测产品表面质量,为指导企业生产实践提供了依据。     

Cytotoxicity of human peripheral blood T-lymphocyte clones activated by hepatitis B virus surface antigen

The present studies examined the cytotoxic activities of peripheral blood lymphocytes (PBL) from volunteers with (sero-positive) and without (sero-negative) circulating antibodies to hepatitis B virus surface antigen before and 30 days after vaccination with hepatitis B virus surface antigen (HBsAg). Long-term culture of monospecific hepatitis B surface (HBsAg)-responsive T-lymphocytes were isolated and grown in large numbers. The mechanism of T-cell mediated cytolysis, and the identification of the carbohydrate determinants on the surface of these effector cells responsible for the killing effect, are being examined.     

Cytotoxicity of human peripheral blood T-lymphocyte clones activated by hepatitis B virus surface antigen

Summary The present studies examined the cytotoxic activities of peripheral blood lymphocytes (PBL) from volunteers with (sero-positive) and without (sero-negative) circulating antibodies to hepatitis B virus surface antigen before and 30 days after vaccination with hepatitis B virus surface antigen (HBsAg). Long-term culture of monospecific hepatitis B surface (HBsAg)-responsive T-lymphocytes were isolated and grown in large numbers. The mechanism of T-cell mediated cytolysis, and the identification of the carbohydrate determinants on the surface of these effector cells responsible for the killing effect, are being examined.     

基于能量平衡模型的陇东黄土高原蒸散发遥感反演——以平凉市崆峒区水土保持世行贷款项目区为例

利用TM遥感影像和地表热量平衡模型估算平凉市崆峒区水土保持世行贷款项目区的蒸散发量,并结合地面实测资料进行检验,分析了该区域蒸散发的分布规律,研究了蒸散发量与土地利用、地表参数、地形参数的关系。结果表明：研究区当日蒸散发量介于0．46～7．85mm之间,平均3．81mm,空间分布差异明显;不同下垫面的蒸散发能力有一定差别,其中水体和林地的日蒸散发量最大;蒸散发量与NDVI和斋程等呈线性正相关,而与地表温度呈线性负相关。本研究可为区域地表水循环和生态修复提供数据支持。     

Origin of ovarian follicle cells in birds

Summary In the embryonic Japanese quail ovary, transplanted on chicken chorioallantoic membrane (CAM), follicle cells are derived from somatic cells of the ovarian surface epithelium. No evidence was found for a contribution of other cell groups of the quail ovary in the formation of follicle cells. This may be demonstrated on PAS stained sections, by following the transfer of carbon particles, initially applied on the surface epithelium.The author is very grateful to Prof.L. Vakaet, R.U.C.A. Antwerp, for his valuables suggestions, and to MissC. van Hoecke for her technical assistance.     

基于模糊C-聚类分析的回采工艺选择及MATLAB实现

煤矿生产中,各个回采工作面的地质条件是影响回采工艺选择的决定性因素,工作面回采工艺选择的合理与否,直接关系到煤炭开采的效率.由于地质因素的不确定性和模糊性,导致了在回采工艺方式选择问题上的复杂性.快速发展的模糊数学为分析这类问题提供了一个很好的解决办法.这里采用模糊数学中C-均值聚类对已采工作面进行分类,并利用分类结果对未采工作面选择何种回采工艺做出预测,这种复杂的计算过程借助了MATLAB逻辑工具箱中的C-均值聚类函数(FCM)来完成,使大量数据的分析得以实现,大大提高了数据处理的效率.     

基于三维地质模型的露天矿模拟开采系统应用研究

为了实现露天矿三维可视化模拟开采,提出了一种快速构建露天矿三维地质模型的方法——包络面构模法。在建立露天矿数字化三维地形／地质模型的基础上,根据露天矿的实际情况建立三维开采模板,自动生成推进模板,从而实现露天矿的模拟开采,使得多方案设计从中选优成为可能,进而提高了采矿设计的速度和质量。     

Separation of specific fractions of synaptosomes by affinity chromatography

Summary The authors describe a new technique for isolation of specific fractions of synaptosomes, on the basis of their surface glycoproteins, by affinity chromatography using lectin-Sepharose columns.     

Unveiling molecular mechanisms of bacterial surface proteins: <Emphasis Type="Italic">Streptococcus pneumoniae</Emphasis> as a model organism for structural studies

Bacteria present a variety of molecules either on their surface or in a cell-free form. These molecules take part in numerous processes in the interactions with their host, with its tissues and other molecules. These molecules are essential to bacterial pathogenesis either during colonization or the spread/invasion stages, and most are virulence factors. This review is focused on such molecules using Streptococcus pneumoniae, a Gram-positive bacterium, as an example. Selected surface proteins are introduced, their structure described, and, whenever available, their mechanisms of function on an atomic level are explained. Such mechanisms for hyaluronate lyase, pneumococcal surface protein A, pneumolysin, histidine-triad and fibronectin-binding proteins are discussed. Elucidation of molecular mechanisms of virulence factors is essential for the understanding of bacteria and their functional properties. Structural biology appears pivotal for these studies, as structural and mechanistic insights facilitate rational approach to the development of new treatments. Received 12 March 2007; received after revision 28 June 2007; accepted 18 July 2007     

Effects of electromagnetic field and lubricate condition on the surface quality of magnesium alloy billet during LFEC processing

The microstructures of the magnesium billets could be improved markedly by low-frequency electromagnetic casting(LFEC)processing.In fact,the low-frequency electromagnetic field(LFEF)also has favorite effect on the surface quality of billet.However,few public reports on the surface quality of LFEC magnesium billets could be found.Therefore,a new crystallizer with a metal internal sleeve together with a kind of lubricant was designed aiming at lowing surface turning quantity,and the effects of casting velocit...     

Identification of rho-antigenic determinants on the surface of mouse T-lymphocytes.

A monospecific antiserum has been prepared in rabbits against purified rho-antigen, a 100,000 mol.wt glycoprotein found on the surface of mouse L-cells. This antiserum has been employed to demonstrate the presence of rho-antigenic determinants selectively on the surface of mouse T-, but not B-lymphocytes.     

SNX3-dependent regulation of epidermal growth factor receptor (EGFR) trafficking and degradation by aspirin in epidermoid carcinoma (A-431) cells

Since being introduced globally as aspirin in 1899, acetylsalicylic acid has been widely used as an analgesic, anti-inflammation, anti-pyretic, and anti-thrombotic drug for years. Aspirin had been reported to down-regulate surface expression of CD40, CD80, CD86, and MHCII in myeloid dendritic cells (DC), which played essential roles in regulating the immune system. We hypothesized that the down-regulation of these surface membrane proteins is partly due to the ability of aspirin in regulating trafficking/sorting of endocytosed surface membrane proteins. By using an established epidermoid carcinoma cell line (A-431), which overexpresses the epidermal growth factor receptor (EGFR) and transferrin receptor (TfnR), we show that aspirin (1) reduces cell surface expression of EGFR and (2) accumulates endocytosed-EGFR and -TfnR in the early/sorting endosome (ESE). Further elucidation of the mechanism suggests that aspirin enhances recruitment of SNX3 and SNX5 to membranes and consistently, both SNX3 and SNX5 play essential roles in the aspirin-mediated accumulation of endocytosed-TfnR at the ESE. This study sheds light on how aspirin may down-regulate surface expression of EGFR by inhibiting/delaying the exit of endocytosed-EGFR from the ESE and recycling of endocytosed-EGFR back to the cell surface.     

Routes and machinery of primary cilium biogenesis

Primary cilia are solitary, microtubule-based protrusions of the cell surface that play fundamental roles as photosensors, mechanosensors and biochemical sensors. Primary cilia dysfunction results in a long list of developmental and degenerative disorders that combine to give rise to a large spectrum of human diseases affecting almost any major body organ. Depending on the cell type, primary ciliogenesis is initiated intracellularly, as in fibroblasts, or at the cell surface, as in renal polarized epithelial cells. In this review, we have focused on the routes of primary ciliogenesis placing particular emphasis on the recently described pathway in renal polarized epithelial cells by which the midbody remnant resulting from a previous cell division event enables the centrosome for initiation of primary cilium assembly. The protein machinery implicated in primary cilium formation in epithelial cells, including the machinery best known for its involvement in establishing cell polarity and polarized membrane trafficking, is also discussed.