oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
运行于SGI工作站的PDMS软件开发应用
崔岩峰,张彩霞,卜繁志
计算机系统应用 , 1995,
Abstract: PDMS是在工作站层次运行的CAD软件,文中介绍了大庆设计院在软件上做的开发应用工作。
黏质黄土地基路基静置时间对工后沉降的影响  [PDF]
裴立军,吴连海
铁道工程学报 , 2010,
Abstract: ?研究目的:通过某客运专线未进行超载预压黏质黄土地基路基段在不同静置时间下,采用曲线拟合法预测路基工后沉降的变化规律研究结论:通过曲线拟合法预测分析得出路基开挖或填筑完成后,一般静置4个月内沉降较大,4~6个月沉降趋势逐渐变缓,达到6个月后路基沉降趋于稳定。采用对数曲线与双曲线预测沉降精确度虽有差异,但可以采取2种曲线预测值平均的方法加以解决,也能够保证预测符合实际情况。
任意点置镜测设曲线的方法及电算程序  [PDF]
楼桿卫,贺晓华
铁道工程学报 , 1997,
Abstract: ?介绍了一种新的曲线测设方法及电算程序——坐标法。它可以在曲线r外任意一点置镜将整个曲线测设完成,从而克眼传统的测量方法(支距法和偏角法〉的误差积累、与置镜点受限制等缺陷,使曲线测量变得快速、准确,特别适合于用全站仪进行的在曲线上的路基、线路、桥梁等的测量。
置镜任一点权坐标法测设曲线精度分析  [PDF]
许勇,李孟山
铁道工程学报 , 1995,
Abstract: ?本文对置镜任一点,光电测距仪(或全站仪)极坐标法测设曲线所产生的误差进行了详细分析,同时给出了从控制点引测测站的最佳方式,测站上的最大测线长度以及曲线测设工作中应注意的一系列问题。
把?置的固定??充分利用起?  [PDF]
地质与勘探 , 1957,
Abstract: ?年?,?着大?模地?勘探工作的?展,地?勘探施工力量和技?装?有了很大的提高。1956年底?????1952年已增加六倍,?年??建和新增固定??也付出不少投资,?於提供地下资源保?国家工?建?起了重要作用。但是,目前地?局系?的固定??中所存在的?置和浪??象是相??重的。具?表现在以下?方面:第一,?於?器??的?置,事先缺乏充分考?,不了解??的?格和性能是否?合地?部?需要,就盲目??。如由局?一向?外??的?台测角?,??北分局岩?部??定,不?用於地?部?。湖南分局?901?
Fatigue Crack Propagation in SGI and CGI  [PDF]
G. Marahleh,A.R.I. Khede,S. Al-Goussous
Journal of Applied Sciences , 2005,
Abstract: Fatigue properties of spheroidal graphite cast iron (SGI) and compacted graphite cast Iron (CGI) were studied in this research. Specimens in form of strips (94x9x3.8 mm) were subjected to alternating bending fatigue tests. S-N curves and fatigue limits for both materials were determined. From the crack growth rate vs. average crack length curves, two behaviors were observed, namely short crack growth rate and long crack growth rate. Mathematical models were suggested describing both types of cracks, thus enabling the calculation of fatigue life of SGI and CGI. From da/dN versus stress intensity variation experiments, the Paris equation da/dN = C (ΔK)P was derived. The smaller the value of p the better is the crack growth resistance of the material. For SGI, p = 1.1855 and for CGI, p = 1.2434 indicating inferior crack growth resistance of the CGI.
Plasma-Based Surface Modification of Polydimethylsiloxane for PDMS-PDMS Molding  [PDF]
S. Lopera,R. D. Mansano
ISRN Polymer Science , 2012, DOI: 10.5402/2012/767151
Abstract: We present and compare two processes for plasma-based surface modification of Polydimethylsiloxane (PDMS) to achieve the antisticking behavior needed for PDMS-PDMS molding. The studied processes were oxygen plasma activation for vapor phase silanization and plasma polymerization with tetrafluoromethane/hydrogen mixtures under different processing conditions. We analyzed topography changes of the treated surfaces by atomic force microscopy and contact angle measurements. Plasma treatment were conducted in a parallel plate reactive ion etching reactor at a pressure of 300?mTorr, 30?Watts of RF power and a total flow rate of 30?sccm of a gas mixture. We found for both processes that short, low power, treatments are better to create long-term modifications of the chemistry of the polymer surface while longer processes or thicker films tend to degrade faster with the use leaving rough surfaces with higher adherence to the molded material. 1. Introduction As reviewed by Macdonald and Whitesides [1], PDMS (polydimethylsiloxane) has proven to be a suitable material for microfluidic device fabrication. It is optically transparent and can be molded to reproduce structures down to nanoscale resolution [2, 3], usually by direct casting on photoresist features over silicon wafers. SU8 is the most commonly used photoresist for master fabrication; single- or multilevel SU8 lines and structures have been extendedly used for PDMS microchannel definition, however, reutilization of resist masters is limited due to degradation by thermal stress during the curing process and by demolding forces. Some strategies such as coatings with diamond-like carbon (DLC) and DLC-polymer hybrids can be applied to increase the durability of the molds [4]. In this paper we present an improved method to replace the use of conventional photoresist masters with more durable positive copies in PDMS. Due to its elasticity, flexible masters in PDMS are not affected by thermal stress during the heating-cooling cycles of the curing process and it is easier to achieve a conformal contact between mold and countermold in closed molding configurations for the production of parts with through holes. Similar methods have been presented to mold complex 3D structures with through holes: Lucas et al. in 2008 [5] presented the use of flexible molds made with freestanding SU8 layers for double-side molding of PDMS, Jo et al. in 2000 [6] used a plastic sheet as countermold for SU8 molds and Janelle et al. in 2000 [7] presented the use of slabs of PDMS treated with
SGI新一代可视化产品发布
中国图象图形学报 , 2005,
Abstract: 2005年4月27日,SGI公司推出了其新一代可视化产品———基于Linux操作系统的Silicon Graphics PrismTM可视计算机产品系列,首次将其最先进的、先前仅有少数人才能用得起的高性能可视化技术置于一个真正开放的平台上。通过将基于标准的英特尔安腾2处理器、Linux操作环境及其世界闻名的先进图形技术相结合,SGI公司为更广泛的用户创建了一个适合解决世界最庞大、最复杂的计算可视化系统。Silicon Graphics PrismTM系统基于SGI NUMAflexTM共享内存结构,可以处理大量复杂数据,以支持目前时实交互环境的需求,在此之上是业界公认的SGI …
Semantic Query Reformulation in Social PDMS  [PDF]
Angela Bonifati,Gianvito Summa,Esther Pacitti,Fady Draidi
Computer Science , 2011,
Abstract: We consider social peer-to-peer data management systems (PDMS), where each peer maintains both semantic mappings between its schema and some acquaintances, and social links with peer friends. In this context, reformulating a query from a peer's schema into other peer's schemas is a hard problem, as it may generate as many rewritings as the set of mappings from that peer to the outside and transitively on, by eventually traversing the entire network. However, not all the obtained rewritings are relevant to a given query. In this paper, we address this problem by inspecting semantic mappings and social links to find only relevant rewritings. We propose a new notion of 'relevance' of a query with respect to a mapping, and, based on this notion, a new semantic query reformulation approach for social PDMS, which achieves great accuracy and flexibility. To find rapidly the most interesting mappings, we combine several techniques: (i) social links are expressed as FOAF (Friend of a Friend) links to characterize peer's friendship and compact mapping summaries are used to obtain mapping descriptions; (ii) local semantic views are special views that contain information about external mappings; and (iii) gossiping techniques improve the search of relevant mappings. Our experimental evaluation, based on a prototype on top of PeerSim and a simulated network demonstrate that our solution yields greater recall, compared to traditional query translation approaches proposed in the literature.
基于遗传算法的工步优化排序方法  [PDF]
张冠伟,赵相松,,,张世昌
计算机集成制造系统 , 2005,
Abstract: 针对数控加工中心上零件加工工步的排序问题,以辅助加工时间最短为优化目标,使用遗传算法对零件在一次装夹情况下的加工工步进行优化排序。提出了使用特征关系图和特征高度描述待加工特征之间加工的优先顺序、采用工步优先关系矩阵校验工步序列合理性的方法。论述了初始群体的生成、遗传算子以及工步优化排序的过程和算法。实际应用表明,该方法可有效提高工艺规划系统中工步的优化排序能力。
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.