高阶中立型偏微分系统的振动性分析(英文)

研究了一类具连续时滞和非线性扩散项的高阶中立型偏微分系统的边值问题,利用积分平均技巧和Riccati方法将高维振动问题转化为一维振动问题,建立了该类边值问题在Dirichlet边界条件下所有解振动的若干新的充分判据。     

主推进动力装置余热利用的研究与探讨

船舶主推进动力装置作为船舶动力的核心部分,产生的余热所占比例较大,品质较高。本文对余热所占比重及使用条件进行了分析,并且对具体设备系统的选择给出了建议。     

Ultimate strength of single shear bolted connections with cold-formed ferritic stainless steel

This paper is focused on the structural behavior of the single shear bolted connections with thin-walled ferritic stainless steel.The purpose of this study is to investigate the ultimate behaviors,such as ultimate strength and fracture mode of the single shear bolted connections of thin-walled ferritic stainless steel(low cost steel) rather than austenitic stainless steel(high cost steel).Bolt arrangement and end distance parallel to the direction of applied load are considered as main variables of the test specimens for bolted connections.Specimens have a constant dimension of edge distance perpendicular to the loading direction,bolt diameter,pitch,and gauge.A monotonic tensile test for specimens has been carried out and some bolted connections with long end distance showed curling(out of plane deformation) occurrence which led to strength reduction.The ultimate behaviors such as fracture mode,ultimate strength are compared with those predicted by current design codes.Further,conditions of curling occurrence and the strength reduction due to curling are investigated and modified strength equations are suggested considering the curling effect.     

Communication for Development: A Personal Experience with Implications for Development Policy

Abstract

Purpose: Communication for Development (C4D) is a new academic discipline and profession for addressing human dimension concerns in development, such as local participation, integration and capacity building, which are the main issues limiting aid effectiveness. However, my experience in Malawi, one of the poorest countries in Africa and where a multitude of international development experts attempt to bring about change have, perhaps, never heard about C4D. When the concept was explained, these officials felt C4D was precisely what Malawi and developing countries, need. It left me feeling that the success rate of poverty-reduction programming could be greater if C4D education was provided for development decision-makers and field staff, especially agricultural extension workers.

Design/methodology/approach: The paper is a critical review of the literature on the role of agricultural extension education in development, focusing on how C4D can strengthen extension performance.

Findings: The study found that development policymakers in Malawi, governmental, nongovernmental, bilateral and multilateral, support the C4D idea once they become knowledgeable about it.

Practical implications: Therefore, the practical implication is that educating policymakers about C4D will increase donor investments in pilot C4D projects, a strengthening of agricultural extension systems, and success of poverty-reduction programs.

Originality/value: It is hoped that readers will find the C4D strategy stimulating, the author's experience enlightening, and the C4D proposal an innovative way of improving aid effectiveness.     

Degradation process of coated tinplate by phase space reconstruction theory

The degradation process of organosol coated tinplate in beverage was investigated by electrochemical noise (EN) technique combined with morphology characterization.EN data were analyzed using phase space reconstruction theory.With the correlation dimensions obtained from the phase space reconstruction,the chaotic behavior of EN was quantitatively evaluated.The results show that both electrochemical potential noise (EPN) and electrochemical current noise (ECN) have chaotic properties.The correlation dimensions of EPN increase with corrosion extent,while those of ECN seem nearly unchanged.The increased correlation dimensions of EPN during the degradation process are associated with the increased susceptibility to local corrosion.     

Smoothing inexact Newton method for solving P 0-NCP problems

Based on a smoothing symmetric disturbance FB-function, a smoothing inexact Newton method for solving the nonlinear complementarity problem with P0-function was proposed. It was proved that under mild conditions, the given algorithm performed global and superlinear convergence without strict complementarity. For the same linear complementarity problem （LCP）, the algorithm needs similar iteration times to the literature. However, its accuracy is improved by at least 4 orders with calculation time reduced by almost 50%, and the iterative number is insensitive to the size of the LCP. Moreover, fewer iterations and shorter time are required for solving the problem by using inexact Newton methods for different initial points.     

Numerical study on viscosity reduction in mining heavy oil by circulating hot water

Viscosity reduction is an important process in mining heavy oil.To predict the temperature variation and viscosity variation of heavy oil in flow direction,computational fluid dynamics(CFD) was adopted to simulate the process of heat transfer and flow in this paper.Moreover,an objective function,namely viscosity reduction efficiency,was established to analyze the effect of viscosity reduction.The results indicate that circulating hot water can reduce viscosity significantly,and that the effect of viscosity reduction depends on the inlet temperature and inlet volumetric flow rate of hot water.There is a maximum temperature of heavy oil in flow direction.With the inlet volumetric flow rate of 2.0m3/h and the inlet temperatures of 60,℃,70,℃ and 80,℃,viscosity reduction efficiencies are 94.6%,96.7% and 97.3%,respectively.With the inlet temperature of 70,℃ and the volumetric flow rates of 1.5m3 /h,2.0 m3/h and 2.5m3/h,viscosity reduction efficiencies are 94.4%,96.7% and 97.2%,respectively.     

The UK edition of The Little Red Schoolbook: a paper tiger reflects

This paper concerns The Little Red Schoolbook, an English translation of the Danish book Den lille røde bog fur skoleelever. After the book's publication in the UK, opponents were successful in pressing for its publisher's prosecution. The ensuing trial led to its withdrawal and its bowdlerisation. It is argued that the work played some part in changing social and sexual mores and sex education practice in the UK, being, in effect, the Urtext of the ‘harm reduction approach’.     

一类非线性系的渐近稳定概周期解

讨论一类概周期系数非线性方程,就其概周期解的存在性、唯一性、稳定性等问题与线性方程系进行比较研究.通过证明发现非线性系具有线性方程系的4条主要性质,且证明了在小指数扰动情况下,非线性系的概周期解仍然保持渐近稳定.     

两个真歧义句的Earley算法演示

从两个真歧义句的组合谈起,借以抽象出“vp ap的np”格式,该格式可以有若干种定界模式,可以举出包括以上两个真歧义句的许多实例;同时介绍了Farley算法的基本操作,构造了一个初步的CFG文法,尝试讨论了歧义的消解策略,并试图通过对以上两个真歧义句的Farley算法的演示表明该算法也可以推广到其他实例的分析中去.