两种硬质合金堆焊焊条的试验对比研究

通过硬度、金相、扫描电镜、能谱分析、拉伸等测试手段,对自制YD型硬质合金堆焊焊条和进口焊条的表面质量、显微组织和力学性能进行对比分析研究。试验结果表明:进口焊条的表面质量更好,呈狼牙棒状,但两种焊条的力学性能和组分差别不大。基体金属与硬质合金结合界面处存在一个过渡区域,两侧组织均发现元素的相互扩散,从而改善堆焊焊条的包覆效果和结合强度。

OPTIMIZATION APPROACH FOR THE MONGE-AMPèRE EQUATION

In this paper, we introduce and study a method for the numerical solution of the elliptic Monge-Ampere equation with Dirichlet boundary conditions. We formulate the Monge-Ampere equation as an optimization problem. The latter involves a Poisson Problem which is solved by the finite element Galerkin method and the minimum is computed by the conjugate gradient algorithm. We also present some numerical experiments.

Survival at Tumor Recurrence in Soft Matter

Survival at tumor recurrence in soft matter, after chemotherapy, is assessed by RNA folding. It is shown that this recurrence is starting with development of a fluidlike globule;it changes the energy of soft matter;it proceeds as a resonant mixing;and at the end it causes diffusion. This diffusion is interpreted as metastasis in soft matter. A tumor memory is designed for its recurrence oscillations. These oscillations are marked as positive or negative according to their influence on life stabilization or destabilization. It is demonstrated that a tumor memorizes two types of recurrences. The intensity of chemotherapy in soft matter for a tumor with such memory is obtained. Survival at tumor recurrence in soft matter, after chemotherapy, is assigned to one of the five regions of the phase diagram of the “thermalized” tumor by microenvironment. To each of these regions is collated a breast cancer survival class. It is found that the survival at tumor recurrence in soft matter, after chemotherapy, well represents actual survival of 32 patients with breast cancer.

Popular Horse Stories and the Invention of the Contemporary Human-Horse Relationship through an Alter Ego Paradigm

From the end of the 19th to the dawn of the 20th century, technological development rendered the use of horse as source of energy and power progressively obsolete, promoting the displacement of its age-old utilitarian functions （transportation, work and war） as well as its social functions as a marker of distinction. Nonetheless, the advent of leisure society encouraged a redefinition of the horse and its social representations, a process spearheaded by the popular arts, especially those meant for child and youth audiences. The purpose of this article is two-fold. The first is to promote an understanding of the historical role of popular arts （literature, movies） in the evolution of the conceptualization of human-horse relationship and the concomitant entrance of horse riding into leisure society, marked by dual processes turning it into an ever-more female and youth-oriented practice. The second is to examine the actual influence of the popular equine arts and the alter ego horse paradigm that they have created on riders＇ current practices. The latter are examined in relation to diverse criteria such as age, gender, type of riding, length of experience, social status and nationality.

Survival Reassessment at Tumor Recurrence in Soft Matter

The paper reassesses a survival at tumor recurrence in soft matter. First, the stability of structural motifs under shear in clusters of dipolar spheres is characterized. Next, there are introduced transitions between polymer knots and rhythms of these transitions are obtained. The sensor is built for these rhythms. Treatment, with a tensile force protocol, is modeled, when the tumor in soft matter is observed by the above sensor. Survival probability, at tumor recurrence in soft matter, is defined for the treatment with a tensile force protocol. It is stated that the survival probability at a tensile force protocol treatment in soft matter confirms or specifies the prognostic survival of 32 patients with breast cancer.

Teaching and Learning from Case Studies:Classroom Application in a Bilingual MBA Program

Case methods of teaching and learning are now popular worldwide in practice-oriented disciplines,especially in business educa tion programs.This reality-and-problem based methodology has attested to be more effective than the traditional inputting mode by link ing theory with practice so as to develop students' ability of creativity,analysis,leadership,communication,problem-solving and the like.However,it becomes more complicated in bilingual context due to the language difficulty.This paper,investigated under the environment of a bilingual(English-Chinese) MBA program in China through the research instruments of class observation,interview and question naire,tries to explore the perceptions of seven case leaders(professors) and their students on the case-based pedagogy in their bilingual courses,and meanwhile,analyze some features and challenges of the classroom practice of cases among these teachers and their English L2 Chinese students.

地球流浪指南

四年前上映的《流浪地球》,开启了国产科幻大片的新时代。而今年上映的前传《流浪地球2》,以更震撼的视觉效果、更丰富的故事情节,展示了这场人类带着地球离开太阳系的宏大远征,究竟是如何开始的。贯穿全片的天文知识元素,为剧情铺陈提供了硬核支撑。

缺血性卒中和短暂性脑缺血发作处理指南2008

本文是对欧洲卒中促进会卒中处理推荐意见的更新。这些指南涵盖了缺血性卒中和短暂性脑缺血发作，目前认为两者在实质上是相同的。文章涉及患者转运、紧急处理、卒中单元服务、诊断、一级和二级预防、卒中的一般治疗以及特殊治疗，后者包括急性期治疗、并发症的处理以及康复治疗。

缺血性卒中和短暂性脑缺血发作处理指南2008

本文是对欧洲卒中促进会卒中处理推荐意见的更新。这些指南涵盖了缺血性卒中和短暂性脑缺血发作,目前认为两者在实质上是相同的。文章涉及患者转运、紧急处理、卒中单元服务、诊断、一级和二级预防、卒中的一般治疗以及特殊治疗,后者包括急性期治疗、并发症的处理以及康复治疗。

Climatic niche shift of an invasive shrub (Ulex europaeus): a global scale comparison in native and introduced regions

Aims Invasive species,which recently expanded,may help understand how climatic niche can shift at the time scale of the current global change.Here,we address the climatic niche shift of an invasive shrub(common gorse,Ulex europaeus)at the world and regional scales to assess how it could contribute to increasing invasibility.Methods Based on a 28187 occurrences database,we used a combination of 9 species distribution models(SDM)to assess regional climatic niche from both the native range(Western Europe)and the introduced range in different parts of the world(North-West America,South America,North Europe,Australia and New Zealand).Important Findings Despite being restricted to annual mean temperature between 4℃ and 22℃,as well as annual precipitation higher than 300 mm/year,the range of bioclimatic conditions suitable for gorse was very large.Based on a native versus introduced SDM comparison,we highlighted a niche expansion in North-West America,South America and to a lesser degree in Australia,while a niche displacement was assessed in North Europe.These niche changes induced an increase in potential occupied areas by gorse by 49,111,202 and 283%in Australia,North Europe,North-West America and South America,respectively.On the contrary,we found no evidence of niche change in New Zealand,which presents similar climatic condition to the native environment(Western Europe).This study highlights how niche expansion and displacement of gorse might increase invasibility at regional scale.The change in gorse niche toward new climatic conditions may result from adaptive plasticity or genetic evolution and may explain why it has such a high level of invasibility.Taking into account the possibility of a niche shift is crucial to improve invasive plants management and control.

来自欧洲南方天文台的最新宇宙图片

架设于智利的欧洲南方天文台拥有四架可独立进行观测的口径为8．2米的反射式望远镜，它们也可以组合成一架甚大望远镜进行工作。该天文台还装备有许多架口径较小的望远镜以及用途各异的其他观测装置。本文精选欧洲南方天文台利用这些观测设备所取得的最新成果，如推断出银河系的年龄和查明银河系中心的结构等，并附有相关图片，以飨读者。