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1.
采用通用蒙特卡罗粒子输运程序MCNP/38计算低环径比Tokamak(紧凑环或球形环)聚变堆第一壁及中心导体上的中子壁负荷分布和核热沉积分布,并与常规Tokamak堆第一壁上中子壁负荷分布和核热沉积分布进行比较、分析。结果表明,在中子壁负荷归一化为1MW/m2时,与常规Tokamak相比,在低环径比Tokamak堆第一壁及中心柱表面上中子壁负荷分布峰值并不比常规Tokamak堆第一壁上的峰值高,而且低于低环径比Tokamak堆整个第一壁上的平均值,而中心柱上的核热沉积峰值稍高于常规Tokamak堆第一壁上的核热沉积峰值,但对较高中子壁负荷情况,中心导体柱上的核热沉积和辐照损伤仍可能是比较严重和值得特别研究的问题。 相似文献
2.
It is suggested that some relaxation processes observed in crystalline polyethylene are consequences of the diffusive motion of a particular defect called a point dislocation or twist dispiration loop along the polyethylene stems in lamellar crystals. The motion of the defect, characterized by a diffusion coefficient and a mobility, is described by solutions of the Smoluchowski diffusion equation with boundary conditions that constrain the defect to move along routes that produce experimentally observable results. The fact that passage of the defect causes both a 180° rotation of the chain and moves an extra CH2 group in the direction of the chain axis is important to the interpretation of the data according to this model. The diffusion coefficient for a defect is estimated to be around 2 × 10?9 cm2 s?1 at 70°C. This value is shown to be reasonable both from the viewpoint of detailed computer modelling of defect motion and contemporary ideas about scaling. 相似文献
3.
Viscoelastic properties of poly(isoprene-b-styrene) in dioctylphthalate under steady shear flow were measured near the order—disorder transition temperature. In ordered states, first normal stress difference N1 is proportional to shear rate
at low
region, but becomes proportional to
at the high
region, similar to the N1 behaviour of polymer blends undergoing shear-induced homogenization. Because the existence of microdomains was confirmed at the high
region by the flow birefringence method, it is concluded that the above N1 behaviour is not caused by shear-induced homogenization, but is probably caused by the shear-induced alignment of the microdomain structure. 相似文献
4.
企业网站设计内容第一的原则,其根本在于企业网站能否吸引和留住客户或潜在客户,它包含三层意思:网站内容的面向对象要准确清晰;针对目标访客的网站内容要紧扣其兴趣中心,从为其带来价值的角度出发,令其感到有收获;促使目标访客对网站内容建立起充分的信任感、解答其疑问。从网站内容方面保证了企业网站对目标访客的吸引力和访问粘度,从而为企业网站实现其既定目标打下了良好的基础。 相似文献
5.
Kathy Shields 《国际互联网参考资料服务季刊》2013,18(3-4):207-218
In Spring 2012, instruction librarians collaborated with first year composition (FYC) faculty to study students’ research habits as they related to writing. We collected process narratives from students in the introductory FYC course at the beginning and end of the fall semester, and a group of librarians and FYC faculty coded them together. Although we did not achieve one of our initial research goals, we still gained valuable insight into how our students perceive sources and the research process. We applied what we learned to create new instructional materials and developed a valuable relationship with FYC faculty. 相似文献
6.
Xiang Zhou 《Information Processing Letters》2008,108(1):3-9
In this article, with Ehrenfeucht-Fraïssé games we prove that Δ1≠Δ0 on BFR, which implies Δ≠Δ0 on BFR, and thus solve an open problem raised by Albert Atserias in his dissertation (Δ0,Δ1,Δ are fragments of first order logic and BFR is a class of finite sets which in essence is equivalent to a class of finite pure arithmetic structures with built-in BIT predicate). 相似文献
7.
We consider a single machine scheduling problem with simple linear deterioration. Job processing times are assumed to be a simple linear function of a job-dependent growth rate and the job's starting time. We seek an optimal schedule, so as to minimize the total absolute deviation of completion times (TADC). We prove several interesting properties of an optimal schedule, and introduce two efficient heuristics which are tested against a lower bound. 相似文献
8.
9.
有限构模器的扩展及其在形式化方法中的应用 总被引:2,自引:0,他引:2
规约在软件开发和验证中占有重要地位,对于以一阶逻辑为基础的规约,可以利用有限模型构造技术对其执行并测试,文中研究规约中某些特性的处理,包括存在量词以及二元关系析传递闭包,对已有的一个构模工具进行扩充,发现了文献中的若干错误。 相似文献
10.
《国际计算机数学杂志》2012,89(5):1012-1029
Many problems in mathematics and engineering lead to Fredholm integral equations of the first kind, e.g. signal and image processing. These kinds of equations are difficult to solve numerically since they are ill-posed. Therefore, regularization is required to obtain a reasonable approximate solution. This paper presents a new regularization method based on a weighted H1 seminorm. Details of numerical implementation are given. Numerical examples, including one-dimensional and two-dimensional integral equations, are presented to illustrate the efficiency of the proposed approach. Numerical results show that the proposed regularization method can restore edges as well as details. 相似文献