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931.
932.
Cu/Ti复合添加对Nd2Fe14B/α-Fe纳米双相磁体磁性能和相分解的影响 总被引:4,自引:0,他引:4
用熔体快淬法制备了高性能纳米双相耦合Nd2Fe14B/α-Fe磁体,研究了Cu/Ti复合添加对Nd2Fe14B/α-Fe纳米双相磁体磁性能和相分解的影响,实验结果表明,Cu和Ti复合添加可提高快淬带的晶化温度,并且改变α-Fe相析出方式,α-Fe直接从TbCu7结构的亚稳相分解中析出,而不是从非晶相中析出,这有利于形成α-Fe相晶粒细小且均匀分布的微结构,其最优磁性能为Hc=384kA/m(4.8kOe),σ=110Am^2/kg(110emu/g),(BH)max=120kJ/m^3(15MGOe)。 相似文献
933.
目的根据质子交换膜燃料电池(Proton Exchange Membrane Fuel Cell,PEMFC)不锈钢双极板的表面镀膜改性要求,探索改性薄膜成分对性能的影响规律,并提供一种行之有效的薄膜成分设计方法。方法首先应用团簇加连接原子结构模型,结合电子轨道饱和原则,理论上设计出Cr-C二元材料体系的最佳团簇式和最佳成分,再利用电弧离子镀技术在316L不锈钢双极板上制备出一系列不同成分的CrxC1-x薄膜,对薄膜的成分、结构及性能进行表征和分析。结果设计所得Cr-C材料体系的最佳团簇式为[Cr-C4]CrC3,对应的最佳原子比成分为Cr0.22C0.78。所制备的CrxC1-x薄膜的成分系数x在0.05~0.23之间变化,薄膜的导电性和耐蚀性能随着成分x的增加,呈明显增加趋势。其中Cr0.23C0.77薄膜的综合性能最好:在1.2MPa压紧力下,接触电阻为2.8 mΩ·cm^2;在模拟腐蚀环境下,腐蚀电流密度仅为9.1×10-2μA/cm^2。该性能已优于美国能源部DOE的标准指标要求。结论Cr-C改性薄膜的成分对导电性能和耐蚀性能有着重要的影响。由于实验制备的性能最佳的薄膜成分Cr0.23C0.77与基于团簇加连接原子模型设计薄膜的最佳成分Cr0.22C0.78基本相同,从而证实了依据此模型进行双极板改性薄膜成分设计是行之有效的。 相似文献
934.
935.
Supply chain management (SCM) is an important strategic tool that requires careful planning and management. While the availability of real-time information is a critical aspect of an SCM system, it possesses a potential to disrupt supply chain participants. Thus, the success of an SCM system hinges on how well participants deal with changes taking place in a real-time environment. This study adopts the concept of the real-time enterprise to understand the role of change management on SCM performance based on the concept of the information orientation. The study empirically validated the role of change management on SCM performance. 相似文献
936.
Travel patterns have gradually changed from group travel to individual travel. An increasing number of people acquire travel information through various types of media. One of the alternative information sources is social media, which enables users to exchange information among members. However, one of the characteristics of social media is information sharing, not information search, which involves both giving (i.e. posting) and taking (i.e. selective reading, forwarding, replying, linking, and liking) information. Compared to the ‘giving’ side of information-sharing research, less effort has been spent on the ‘taking’ side of information research. Therefore, we investigate travel information adoption in social media as well as how individuals communicate with each other. We use the elaboration likelihood model, which measures the impact of central (e.g. argument quality) and peripheral (e.g. credibility) cues on traveller information-sharing behaviour corresponding with social presence on social media. The results of an empirical analysis of 527 respondents, who were experienced in travel information adoption via social media, were examined. Our findings revealed that argument quality had a positive effect on perceived usefulness and source credibility positively affected perceived usefulness and social relationships. Perceived usefulness had a significant positive effect on social relationships. Both perceived usefulness and social relationships affected travel information adoption. Lastly, the levels of argument quality and source credibility perceived by social media members were found to differ according to the level of social presence. 相似文献
937.
Due to the fast development in data communication systems and computer networks in recent years, the necessity to protect the secret data has become extremely imperative. Several methods have been proposed to protect the secret data; one of them is the secret sharing scheme. It is a method of distributing a secret K among a finite set of participants, in such a way that only predefined subset of participant is enabled to reconstruct a secret from their shares. A secret sharing scheme realizing uniform access structure described by a graph has received a considerable attention. In this scheme, each vertex represents a participant and each edge represents a minimum authorized subset. In this paper, an independent dominating set of vertices in a graph G is introduced and applied as a novel idea to construct a secret sharing scheme such that the vertices of the graph represent the participants and the dominating set of vertices in G represents the minimal authorized set. While most of the previous schemes were based on the principle of adjacent vertices, the proposed scheme is based upon the principle of non-adjacent vertices. We prove that the scheme is perfect, and the lower bound of the information rate of this new construction is improved when compared to some well-known previous constructions. We include an experiment involving security threats to demonstrate the effectiveness of the proposed scheme. 相似文献
938.
939.
940.
In the present research, N = 48 adults without university education were tasked to conduct two web searches on unfamiliar health-related issues. Three research objectives were examined: the predictive value of individuals’ Internet-specific epistemic beliefs for their navigation behavior and post-search decisions in Web Search Task 1; the effects of a short source evaluation intervention on individuals’ navigation behavior and post-search decisions in Web Search Task 2; and the effects of the source evaluation intervention on individuals’ Internet-specific epistemic beliefs. Results showed that beliefs concerning the justification by multiple sources were positively related to the time spent on reliable objective web pages and to the likelihood to make a post-search decision that was in accordance with the objective pages. Beliefs that the Internet is a reliable knowledge resource were also positively related to the time spent on objective pages as well as to greater certainty in the post-search decision. Second, in Web Search Task 2, the intervention group spent more time on objective web pages, was more likely to make a decision that was in accordance with these pages, and was more certain of their decision than the control group. Third, one week after the intervention, individuals possessed stronger beliefs concerning the justification by multiple sources than before. In conclusion, the present research indicates that both adaptive Internet-specific beliefs and a short source evaluation intervention have positive effects on non-university educated adults’ online health information seeking and that their Internet-specific epistemic beliefs can be fostered through such an intervention. 相似文献