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1.
利用AutoCAD求解机构运动学和动力学问题   总被引:1,自引:1,他引:0  
提出采用AutoCAD求解机构运动学和动力学问题,并结合实例给出了方法与步骤。 此求解法既有图解法简单明了的特点,又能满足了现代机械设计对运动分析和动力分析的高精度 的要求,具有较高的可靠性和实用性。  相似文献   
2.
基于语义分析的设计实体智能搜索   总被引:1,自引:0,他引:1  
本文提出了在设计联盟组织过程中实现互联网上设计实体智能搜索的方法。根据对互联网上设计实体搜索问题的分析建立了设计实体智能搜索策略;定义了提取设计实体查询向量和描述向量的语义分析规则;提出了基于语义分析的设计实体智能搜索算法;最后编程实现了各项功能。  相似文献   
3.
提出了一种基于平面隐函数的实体切割思想和区域自动识别技术的地质体剖面图生成方法。其主要步骤包括:采用平面隐函数实现平面和地质实体的求交运算,生成离散的交线;采用基于KD树的空间索引方法,确定交线的邻接关系,生成地质体轮廓线;封闭的轮廓线将平面划分为多个复杂的区域(内含孔、岛),采用图论的多叉树形式化表达区域存储和组织;最后对多叉树表示的区域进行矢量图案的填充。实验结果表明,该算法有较好的计算效率,是一种比较实用的地质体剖切方法。  相似文献   
4.
维基百科实体分类对自然语言处理和机器学习具有重要的作用。该文采用机器学习的方法对中文维基百科的条目进行实体分类,在利用维基百科页面中半结构化信息和无结构化文本作为基本特征的基础上,结合中文的特点使用扩展特征和语义特征来提高实体分类性能。在人工标注的语料库上的实验表明,这些额外特征有效地提高了ACE分类体系上的实体分类性能,总体F1值达到96%,同时在扩展实体分类上也取得了较好的效果,总体F1值达95%。
  相似文献   
5.
The aqueous-core enclosed in lipid nanoballoons integrating multiple emulsions of the type water-in-oil-in-water mimic, at least in theory, the environment within viable cells, thus being suitable for housing hydrophilic protein entities such as bioactive proteins, peptides and bacteriophage particles. This study reports a complete physicochemical characterization of optimized biomimetic aqueous-core lipid nanoballoons housing hydrophilic (BSA) protein entities, evolved from a statistical 23×31 factorial design study (three variables at two levels and one variable at three levels) that was the subject of the first paper of a series of three, aiming at complete stabilization of the three-dimensional structure of protein entities attempted via housing the said molecular entities within biomimetic aqueous-core lipid nanoballoons integrating a multiple (W/O/W) emulsion. The statistical factorial design followed led to the production of an optimum W/O/W multiple emulsion possessing quite homogeneous particles with an average hydrodynamic size of (186.2?±?2.6) nm and average Zeta potential of (?36.5?±?0.9) mV, and exhibiting a polydispersity index of 0.206?±?0.014. Additionally, the results obtained for the diffusion coefficient of the lipid nanoballoons integrating the optimized W/O/W multiple emulsion were comparable and of the same order of magnitude (10?12 m2 s?1) as those published by other authors since, typically, diffusion coefficients for molecules range from 10?10 to 10?7 m2 s?1, but diffusion coefficients for nanoparticles are typically of the order of magnitude of 10?12 m2 s?1.  相似文献   
6.
Developing future weapons systems has become increasingly complicated and costly. The armed forces of major nations use modeling and simulation techniques for new weapons systems from the conceptual stage to design, production, deployment and training stages to shorten the development cycle and guarantee their effectiveness. Failure in the development cycle carries too much loss in time and money. Therefore, computer-based modeling and simulation techniques are applied from the conceptual stage to gauge the efficacy of new weapons systems. The objective of this study is to develop a modeling and simulation methodology for small scale engagement using the DEVS formalism. The entities required for modeling and simulation are divided into three categories: combat, logical, and environmental entities. Combat entities represent the military hardware or combatants; logical entities represent the judgment and decision entities for the interaction between various entities; and environmental entities emulate the constituents of real combat environment. The combat entities are further modeled into Shell and Core Parts to maximize their reusability under various combat scenarios. The proposed framework is verified using a one-on-one combat engagement simulation (written in C++) between two submarines.  相似文献   
7.
R. W. Firestone's Cityscape Pink is a bold image capturing the essence of a city. In this Longer View essay, Bruce McClendon argues that the profession of planning needs a similarly bold vision and compelling brand identity in order to claim its proper place among many competitors offering similar services. He aims to distinguish the planning profession in the eyes of the public and the minds of planners themselves. Three commenters respond with different perspectives on the status of the profession and how best to improve it.

Firestone is a psychotherapist with a PhD in clinical psychology from the University of Denver and the author of nine books. He grew up in the New York City area and opened his private practice in Los Angeles, treating patients suffering from schizophrenia. With a group of friends he has sailed to many parts of the world, and both his practice and his travels figure into the subjects of his artwork.

Planning has become a generic product in a confusing, overcrowded, and highly competitive marketplace. The public does not know what planning is or how to differentiate among planning specialists. Relying on a bold back-to-the-future approach, I argue that it is the production, administration, and implementation of comprehensive plans that once was and still is the profession's unique and distinctive technical competency and core mission. By using branding techniques to define, link, and reconnect planners with comprehensive planning, it will be possible to tell the planning story in a way that communicates the emotional benefits and value of the profession and strengthens the public's respect and appreciation for planners.  相似文献   
8.
Based on previous findings (Jans, U., Hoigné, J., 1998. Ozone Sci. Eng. 20, 67-87), the activity of activated carbon for the transformation of ozone into *OH radicals including the influence of operational parameters (carbon dose, ozone dose, carbon-type and carbon treatment time) was quantified. The ozone decomposition constant (k(D)) was increased by the presence of activated carbon in the system and depending on the type of activated carbon added, the ratio of the concentrations of *OH radicals and ozone, the R(ct) value ([*OH]/[O3]), was increased by a factor 3-5. The results obtained show that the surface chemical and textural characteristics of the activated carbon determines its activity for the transformation of ozone into *OH radicals. The most efficient carbons in this process are those with high basicity and large surface area. The obtained results show that the interaction between ozone and pyrrol groups present on the surface of activated carbon increase the concentration of O2*- radicals in the system, enhancing ozone transformation into *OH radicals. The activity of activated carbon decreases for extended ozone exposures. This may indicate that activated carbon does not really act as a catalyst but rather as a conventional initiator or promoter for the ozone transformation into *OH radicals. Ozonation of Lake Zurich water ([O3] = 1 mg/L) in presence of activated carbon (0.5 g/L) lead to an increase in the k(D) and R(ct) value by a factor of 10 and 39, respectively, thereby favouring the removal of ozone-resistant contaminants. Moreover, the presence of activated carbon during ozonation of Lake Zurich water led to a 40% reduction in the content of dissolved organic carbon during the first 60 min of treatment. The adsorption of low concentrations of dissolved organic matter (DOM) on activated carbon surfaces did not modify its capacity to initiate/promote ozone transformation into *OH radicals.  相似文献   
9.
An appropriate promotion, distribution and dissemination of scientific, artistic and technology developments can foster the collaboration between a country’s productive and academic sectors. The purpose of this paper is to present a novel search engine aiming at helping people to access science and technology advances, researchers and institutions working in specific areas of research. Our search engine first collects information disseminated on the Web in academic institution sites and in researchers personal homepages. Then, after intensive text processing, it summarizes the information in an enriched and user-friendly presentation oriented to non-expert users. Stable performance and an acceptable level of effectiveness for automatic named entities recognition indicate the potential of our approach for bridging the gap between the heterogeneous and unstructured information available on the Web about the research and development advances in a country and the innovation required by the productive sectors.  相似文献   
10.
采购实体清单是GPA出价中重要的要素之一。除了出价清单中的采购实体外,特定的关联关系可能会涉及到出价清单外实体的采购规则适用问题。本文根据GPA文本、案例和出价中分析了主要涉及的三种关联关系(实体关联、业务关联和采购关联),对这三种关联关系的具体情形进行了解析,并研究相对应适用的采购规则,进而对我国GPA出价提出建议。  相似文献   
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