继承,发展,开拓,创新

<正>今天是郭永怀先生诞辰110周年,我想就怎样传承郭先生的崇高精神和学术思想,并且落实到我们的实际工作中去谈一点感想。首先,因在简短的发言中不能全面回顾郭先生60年的光辉一生,但其中有一个事例特别值得我们深思。郭先生生活年代的中国是"东亚病夫",不能抵御日本人的侵略,所以,当时的热血青年都在思考救国之道。20世纪上半叶是航空工业突飞猛进的时     

Structure, Surface, Interaction and Time

Recent years have witnessed the rapid growth and sale of new products in the field of functional materials, together with a relative decline in new products and new processes in the field of commodity chemicals. Different from the commodity chemicals which arecommonly produced by continuous processes in megaquantities, the functional materials are usually produced bybatch processes in small quantities. The utility of the functional materials depends not only on their chemical composition and purity but also on their structures and surfaces,which are governed by what occurs at a molecular/nano scale rather than at the process scale. What knowledge     

COMPOSITION OF INDOOR AEROSOLS AT EMPEROR QIN''''S TERRA-COTTA MUSEUM, XI''''AN, CHINA, DURING SUMMER, 2004

Particle samples were collected in August 2004 both inside and outside Emperor Qin's Terra-Cotta Museum in Xi'an, China. Mass and chemical composition of total suspended particles (JSP, particles with aerodynamic diameter less than-30μm), PM2.5(particles with aerodynamic diameter <2.5μm) were determined. The average levels of indoor PM2.5 and TSP were 108.4 and 172.4 μg·m-3, respectively, with PM2.5 constituting 62.9% of the TSP mass. Sulfate ((32.4±6.2)%), organics ((27.7±8.0)%), and geological material ((12.5±3.4)%) dominated indoor PM2.5, followed by ammonium ((8.9±2.8)%), nitrate ((7.0±2.9)%), and elemental carbon (EC, (3.9±1.5)%). Particle size distribution varied with the number of tourists in the museum. The size of sulfate, organics, EC, nitrate, and ammonium was found to vary in the range of 0.43 to 3.3 μm in fraction. Ion balance indicated that the aerosol was acidic, with insufficient ammonium ions to neutralize the sulfuric and nitric acids. High concentrations of acidic aerosols will erode the Terra-cotta warriors and horses especially in the summer season with high temperature (30℃) and relative humidity (70%) and undesirable solar radiation inside the museum. More attention should be paid to protecting these precious antiques made 2000 years ago.     

举办专题讲座,联系现代科技,培养创造精神

本文论述在教学中举办专题讲座的重要意义．     

混合,浑沌性平流,和湍流

<正> 1 引言 1.1 背景 流体混合范型(paradigm)的建立,可以大大影响物理科学和技术科学的许多分支学科的发展.混合跟湍流,地球科学和自然科学,以及工程学各分支学科都密切相关.然而,尽管混合具有普适性,但令人奇怪的却是,很少有人去致力于构造一个一般的分析框架.考察一下任何图书馆的索引,就会发现,几乎没有什么著作——教科书或者专著——是从全局展望的高度上来着重论述混合现象这一流体力学问题的.事实上,自从“流体力学年评(Annual Review of Fluid Mechanics)力1969年第1卷出版以来,一直很少发表专门     

鼓励独创,注重实效,深化理论力学教学改革

１理论力学教学改革的指导思想 随着教改的深人,在不断探索和实践的基础上,我们确立了继承“敬业、求实”的我校理论力学教学集体的优良传统,鼓励独创、注重实效的教学指导思想．鼓励任课教师瞄准培养学生全面素质与创新能力的目标,结合自己的科研特点和所承担教学班的特点,对课程体系、课程内容、教学方法和手段等进行研究与实践．在教学改革的研究与实践过程中,我们认识到教师的创造性和全面素质提高是教学改革成功的前提和保障,同时教学改革也正是培养教师自身全面素质和创造性的过程．因此我们支持教师对课程的独创性改革,不搞…     

UNIFIED DEFINITION OF DIVERGENCE,CURL,AND GRADIENT

In this note the differential expressions of divergence,curl,and gradient are derivedbased on one common model.Each of them involves the limiting value of a differentialquantity per nuit volume.By taking advantage of some differential relations of the unitvectors weighted by the metric coefficients,the full expression of these three quantities invector analysis can be readily derivde.     

PM2.5 in China： Measurements,sources, visibility and health effects,and mitigation

Concern over the health effects of fine particles in the ambient environment led the U.S. Environmental Protection Agency to develop the first standard for PM2.5 （particulate matter less than 2.5 μm） in 1997. The Particle Technology Laboratory at the University of Minnesota has helped to establish the PM2.5 standard by developing many instruments and samplers to perform atmospheric measurements. In this paper, we review various aspects of PM2.5, including its measurement, source apportionment, visibility and health effects, and mitigation. We focus on PM2.s studies in China and where appropriate, compare them with those obtained in the U.S. Based on accurate PM2.5 sampling, chemical analysis, and source apportionment models, the major PM2.5 sources in China have been identified to be coal combustion, motor vehicle emissions, and industrial sources. Atmospheric visibility has been found to correlate well with PM2.s concentration. Sulfate, ammonium, and nitrate carried by PM2.s, commonly found in coal burning and vehicle emissions, are the dominant contributors to regional haze in China. Short-term exposure to PM2.s is strongly associated with the increased risk of morbidity and mortality from cardiovascular and respiratory diseases in China. The strategy for PMzs mitigation must be based on reducing the pollutants from the two primary sources of coal-fired power plants and vehicle emissions. Although conventional Particulate Emission Control Devices （PECD） such as electrostatic precipitators in Chinese coal-fired power plants are generally effective for large particles, most of them may not have high collection efficiency of PM2.5. Baghouse filtration is gradually incorporated into the PECD to increase the PM2.5 collection efficiency. By adopting stringent vehicle emissions standard such as Euro 5 and 6, the emissions from vehicles can be gradually reduced over the years. An integrative approach, from collaboration among academia, government, and industries, can effectively manage and mitigate the PM2.s p     

不信天,不信命,紧跟毛主席干革命

几千年来,反动的统治阶级总是颠倒历史,恶毒诬蔑劳动群众,胡说什么“唯上智与下愚不移”,反动统治者生来就是聪明的“贵人”,应该主宰世界;而劳动人民是命里注定的“蠢人”,只能是任人驱使的奴隶。孔老二为了维护奴隶主贵族的利益,实现“克已复礼”的目的,炮制了“生而知之”、“上智”、“下愚”等谬论,拼命给反动统治者脸上涂脂抹粉,把他们吹捧为“怀德”、“喻于义”的“君子”和“上智”,而恶毒诬蔑劳动人民为“怀土”、“喻于利”     

《系统生物学—建模,分析,模拟》书评

生命活动属于最复杂的自然界现象。近代生物学研究已从以实验观察为主的方式逐步发展为与生命体的机理性分析密切结合,并且由生物器官组织的宏观形态和表型向生物细胞和分子的微观行为和演变进行深入探讨。随着生物科学实验技术和方法的飞速进步,人们对生物大分子、基因和蛋白质、生物膜的结构和功能等的研究已经积累了相当丰富的知识。由于生命现象都是生物复杂大系统的综合行为的结果,我们必须把生物系统作为一个整体来研究,从系统论的角度进一步探讨细胞的信息、生长、发育、分化、代谢等动态过程以及生物有机体的功能,而不仅把研究重点放在单个的基因, 蛋白质或者器官上。系统生物学就是这样一门研究生物系统的内部组分结构, 以及在各种内、外部条件下这些组分的相互作用和演化规律的学科,是生命科学的一个前沿领域。目前重点是在分子层次上开展对生命现象（例如遗传基因、蛋白质、重大疾病等）的过程和机制的研究,生物化学反应（包括蛋白质—蛋白质相互作用、DNA—蛋白质相互作用等）和生物网络（包括基因网、蛋白质相互作用网、信号转导网、代谢网等）行为在其中起着重要作用。大量的系统生物学研究对象是动态的和随机的,涉及不同的时空尺度下复杂非线性动力学与控制问题。      

研究了雷诺数Re=200, 1000, 线速度比$\alpha =0.5$,

研究了雷诺数Re=200, 1000, 线速度比$\alpha =0.5$, 2.0, 4.0, 强迫振荡频率$f_{s}=0.1\sim 2.0$情况下的旋转振荡圆柱绕流问题. 通 过基于非结构同位网格有限体积法对Navier-Stokes方程进行数值求解. 对流项、扩 散项和非恒定项的离散格式均具有二阶精度，利用SIMPLE算法处理压力-速度耦合. 计算得到了作用力系数随不同控制参数的变化规律. 通过对升力系数的频谱分析得到 自然脱落频率和强迫振荡频率下的作用力振幅. 通过对不同频率作用力幅值的分析， 得到频率之间的竞争关系，进而定量地给出了不同尾迹涡脱落模式的分区图.