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151.
采用人工神经网络方法建立了钢-铝固液相复合中助焊剂质量分数,铝液温度,模具温度,压力与界面层厚度间的关系型,并结合最大剪切强度的复合工艺参数得出了钢-铝固液相压力复合的最佳界面界厚度的10.0μm。 相似文献
152.
基于PLC的液压机电气控制系统的设计,我们可以利用软件代替传统的硬件电路系统,且系统控制性能优良,运行可靠。 相似文献
153.
研究了从高温超导YBCO融熔织构材料中分离出单颗粒边界的工艺。采用聚酰亚胺材料作为绝缘层,从单颗粒上引起出电压测量引线,实现了对单颗粒边界传输特性的测量。实验观察到这类样品中的颗粒边界在不同的传输特性,包括磁通流类型和Josephson弱连接类型。 相似文献
154.
155.
KANGDa-zhou XUBao-wen LUJian-jiang WANGPeng LIYan-hui 《武汉大学学报:自然科学英文版》2004,9(5):575-579
This paper introduces the definition and calculation of the association matrix between ontologies, h uses the association matrix to describe the relations between concepls ill different ontologics and uses concept vectors to represent queries; then computes the vectors with the association matrix in order to rewrite queries, This paper proposes a simple method of querying through heterogeneous Ontology using association matrix. This method is based on the correctness of approximate information filtering theory; and it is simple to be implemented and expected to run quite fast. 相似文献
156.
杭州市"构筑大都市,建设新天堂"人才战略的思考 总被引:1,自引:0,他引:1
王康 《杭州师范学院学报(自然科学版)》2004,3(6):464-466
在分析杭州市人才战略的宏观背景、杭州市人才工作现状的基础上,比较系统地论述了杭州市"构筑大都市,建设新天堂"的人才战略育人战略、引智战略、人才市场发展战略、创业环境营造战略. 相似文献
157.
康承华 《福州大学学报(自然科学版)》1982,(1):79-86
本文系统化了非平衡热力学和耗散结构的若干辩证法问题,同时,提出了平衡热力学、线性热力学和非线性热力学的适用条件及关系.这些关系写成一表以便互相比较.文章认为非线性热力学是普遍的理论,它能应用到远离平衡态,然而,这远离平衡仍是有限的.远离平衡是相对于近平衡的概念,其精确定义是不满足JK=∑iLKiXi的非平衡态. 相似文献
158.
Transformation: a tool for studying fungal pathogens of plants 总被引:18,自引:0,他引:18
Plant diseases caused by plant pathogenic fungi continuously threaten the sustainability of global crop production. An effective
way to study the disease-causing mechanisms of these organisms is to disrupt their genes, in both a targeted and random manner,
so as to isolate mutants exhibiting altered virulence. Although a number of techniques have been employed for such an analysis,
those based on transformation are by far the most commonly used. In filamentous fungi, the introduction of DNA by transformation
typically results in either the heterologous (illegitimate) integration or the homologous integration of the transforming
DNA into the target genome. Homologous integration permits a targeted gene disruption by replacing the wild-type allele on
the genome with a mutant allele on transforming DNA. This process has been widely used to determine the role of newly isolated
fungal genes in pathogenicity. The heterologous integration of transforming DNA causes a random process of gene disruption
(insertional mutagenesis) and has led to the isolation of many fungal mutants defective in pathogenicity. A big advantage
of insertional mutagenesis over the more traditional chemical or radiation mutagenesis procedures is that the mutated gene
is tagged by transforming DNA and can subsequently be cloned using the transforming DNA. The application of various transformation-based
techniques for fungal gene manipulation and how they have increased our understanding and appreciation of some of the most
serious plant pathogenic fungi are discussed.
Received 9 May 2001; received after revision 2 July 2001; accepted 3 July 2001 相似文献
159.
国际互联网技术与旅游业企业过程重组 总被引:2,自引:0,他引:2
信息技术、互联网、通讯技术的发展引起了整个旅游业的一场革命,正在深刻地改变着旅游业的经营、管理和运作模式。网络技术的出现则恰好给旅游业的加速发展、企业过程重组带来了新的机遇。文章集中分析了旅游业的信息特征、信息技术、互联网技术引起的旅游业的经营环境变化,提出了旅游服务供应链管理的概念。在此基础上,结合英特网技术在旅游业的功能,提出了旅游业的企业过程重组,建立虚拟旅游公司模式。 相似文献
160.
Kang HJ Dai P Lynn JW Matsuura M Thompson JR Zhang SC Argyriou DN Onose Y Tokura Y 《Nature》2003,423(6939):522-525
Superconductivity in the high-transition-temperature (high-T(c)) copper oxides competes with other possible ground states. The physical explanation for superconductivity can be constrained by determining the nature of the closest competing ground state, and establishing if that state is universal among the high-T(c) materials. Antiferromagnetism has been theoretically predicted to be the competing ground state. A competing ground state is revealed when superconductivity is destroyed by the application of a magnetic field, and antiferromagnetism has been observed in hole-doped materials under the influence of modest fields. None of the previous experiments have revealed the quantum phase transition from the superconducting state to the antiferromagnetic state, because they failed to reach the upper critical field B(c2). Here we report the results of transport and neutron-scattering experiments on electron-doped Nd1.85Ce0.15CuO4 (refs 13, 14), where B(c2) can be reached. The applied field reveals a static, commensurate, anomalously conducting long-range ordered antiferromagnetic state, in which the induced moment scales approximately linearly with the field strength until it saturates at B(c2). This and previous experiments on the hole-doped materials therefore establishes antiferromagnetic order as a competing ground state in the high-T(c) copper oxide materials, irrespective of electron or hole doping. 相似文献