weblog Part II - tranferred from space.live

4月16日
Task for this week

How time flies! Today is Monday again. This moring, I submitted the application for housing on campus. Hope that the resulte is exactly my expection . This week, the following things should be done on time:

1. preparing for lecturing on the seminar on multiscale modelling.

2. finish the code for QDD
sketch of algorithm:
2.1 given density n, solving Poisson equation, which is rewritten in terms of electric field E, to get the analytical solution E.
2.2 computing \pt E / \pt n, preparing for Newton method.
2.3 utilizing Newton-Ralphson method to update n.

3. make possible plan for this weekend, maybe go to some park or meet some friends.

4. practice badminton on Tue. night from 9 pm to 11 pm.

5. practice in-line skate tonight, from 10:30 pm. more when time is available.

21:55

4月11日
express love in 77 languages

第一种汉语的是：我爱你。
法语：Je t’aime,Je t’adore
德语：Ich liebe Dich
希腊语：S’agapo
犹太语：Ani ohev otach(male or famale),Ani ohevet otcha (male or famale)
匈牙利：Szeretlek
爱尔兰：taim i’ngra leat
爱沙尼亚：Mina armastan sind
芬兰：Min rakastan sinua
比利时佛兰芒语：IK zie u graag
意大利语：ti amo,ti vogliobene
拉丁语：Te amo,Vos amo
拉托维亚：Es tevi Milu
里斯本：lingo gramo-te bue’,chavalinha
立陶宛：Tave Myliu
马其顿：Te sakam
马耳他：Inhobbok
波兰语：Kocham Cie,Ja cie kocham
葡萄牙：Eu amo-te
罗马尼亚：Te iu besc,Te Ador
荷兰：IK hou van jou
英语：I love you
捷克：Miluji te
丹麦：Jeg elsker dig
阿尔萨斯：Ich hoan dich gear
亚美尼亚：Yes Kezi Seeroom yem
巴伐利亚：I mog di narrisch gern
保加利亚：ahs te obicham
西班牙加泰隆语：T’estim
克罗地亚：Volim te
阿塞疆语：Men seni serivem
孟加拉：Ami tomay bhalobashi
缅甸：chit pa de
柬埔寨：Bong salang oun
菲律宾：Mahal Kita,Iniibig Kita
印度古吉拉特语：Hoon tane prem karun chuun
北印度语：main tumse pyar karta hoon
印度尼西亚：Saja kasih saudari
日本：Kimi o aishiteru Sukiyo
朝鲜：Tangshin-i cho-a-yo
爪哇语：aku tresno marang sliromu
老挝：Khoi huk chau
马来语：saya Cinta Mu
马来西亚：Saya Cintamu
蒙古语：bi chamd hairtai
尼泊尔：Ma tumilai maya garchu,Ma timilai man parauchu
波斯语：Tora dost daram
他加禄语：Mahal kita
南非语：Ek het jou lief Ek is lief vir jou
加纳：Me do wo
埃塞俄比亚阿姆哈雷地区：Ene ewedechalu(for ladies) Ene ewedehalwe(for men)
阿拉伯语：Ana Ahebak(to a male) Arabic Ana ahebek(to a female)
瑞士德语：Ich lib Dich
克里奥尔语：Mon kontan ou
豪萨语：Ina sonki
肯尼亚班图语：Nigwedete
马达加斯加语：tiako ianao
印度阿萨姆邦语：Moi tomak bhal pau
南亚泰米尔语：Tamil n’an unnaik kathalikkinren
印度泰卢固语：Neenu ninnu pra’mistu’nnanu
泰国：Ch’an Rak Khun
乌尔都语：Mein tumhay pyar karti hun(woman to man) Mein tumhay pyar karta hun(man to woman)
越南：Em ye’u anh(woman to man) Anh ye’u em(man to woman)
新西兰毛里语：kia hoahai
爱斯基摩：Nagligivaget
格陵兰岛：Asavakit
冰岛：e’g elska tig
阿尔巴尼亚：T Dua Shume
俄罗斯：Ya vas Iyublyu,Ya Tibia Lyublyu
塞尔维亚：Volim Te
斯洛文尼亚语：Ljubim te
西班牙：Te amo,Tequiero
瑞典：Jag lskar dig
土耳其：Seni seviyorum
乌克兰：ja vas kokhaju
威尔士：Rwy’n dy garu di
亚述语：ana bayanookh(female to male) ana bayinakh(male to female)
高加索切尔克斯语：wise cas

16:57

4月9日
Colloquium to be attended

4月10日工学院力学与空天技术系学术报告
题　目：DNS and Modeling of Turbulent Premixed Flames
报告人： Prof. Tatsuya HASEGAWA
EcoTopia Science Institute, Nagoya University, Japan

报告摘要：
Turbulent premixed flames propagating in homogeneous isotropic turbulent flows were directly simulated with different density ratios and with different Lewis numbers. These DNS databases were investigated by analyzing Favre averaged transport equations for turbulent kinetic energy and turbulent scalar flux to study flame-generated turbulence and counter-gradient diffusion. Modeling of important terms in the balance equations of turbulent kinetic energy and turbulent scalar flux were also discussed. These modeled equations were used to simulate turbulent premixed flames with flame-generated turbulence and counter-gradient diffusion. Analyses of turbulent burning velocity were also performed using newly calculated DNS databases with different Lewis numbers.

报告人简介：
Research field:
Combustion, Heat Transfer, Fluid Mechanics, Computational Fluid Dynamics, Environmental Engineering, Mechanical Engineering, Aerospace Engineering
Research subject:
Direct numerical simulation and modeling of turbulent premixed combustion
Reaction mechanism and heat production in hydrothermal processes
Hydrothermal gasification of biowastes and fuels
Highly efficient air conditioning system using HFC and natural refrigerant
Thermoplastic welding by diode laser
Academic career:
1977 B. S. Engineering, Department of Aeronautics, Nagoya University
1983 Dr. Engineering, Nagoya University
1983 Research Associate, Nagoya Institute of Technology
1987 Associate Professor, Nagoya Institute of Technology
2002 Professor, Center for Integrated Research in Science and Engineering, Nagoya University
2004 Professor, EcoTopia Science Institute, Nagoya University

主持人：王健平 教授
时 间：4月10日（周二）下午4点
地 点：力学与空天技术系大风洞会议室

题目：Asymptotic Cohesive Crack Tip Fields, Complete Displacement Field of Hybrid Crack Element and XFEM
报告人： B.L. Karihaloo
School of Engineering, Cardiff University, Cardiff CF24 3AA, UK
主持人：王建祥 教授
时 间：4月16日（周一）下午3点
地 点：北京大学力学楼434会议室
This talk will introduce three recent developments in linear and non-linear fracture mechanics. The first development is the asymptotic fields at the tip of a cohesive crack. The lack of any work on the asymptotic fields at the tipof a cohesive crack is surprising considering the widespread use of cohesivecrack models. This blank has recently been filled by Xiao and Karihaloo (2006) who obtained universal asymptotic expansions at a cohesive crack tip, analogous to Williams’s expansions at a traction-free crack tip. The coefficients of the expansions of course depend nonlinearly on the softening law and theboundary conditions. These universal expansions are valid for any normal cohesion-separation law (i.e. softening law) that can be expressed in a special polynomial form. They demonstrated that many commonly-used cohesion-separation laws, e.g. rectangular, linear, bilinear and exponential, can indeed be expressed very accurately in this special form. They also obtained universal asymptotic expansions when the cohesive crack faces are subjected to Coulomb friction.The hybrid crack element (HCE) is one of the most accurate and convenient finite elements (FEs) for the direct calculation of the stress intensity factor (SIF) and coefficients of the higher order terms of the Williams expansion. This talk will introduce two new developments of the element. Firstly, a leastsquares method (LSM) is introduced to recover the rigid body modes excluded from the HCE formulation, which create jumps between the truncated asymptoticdisplacements and element boundary displacements. The LSM minimises these jumps. Then an approach is introduced to combine the HCE and the extended/generalized finite element method (XFEM). The HCE is used for the crack tip region, while the XFEM is used for modelling crack faces behind the crack tip with jump functions. The coupled method retains the advantages of both HCE and XFEM. Numerical results are presented to illustrate these developments.报告人简介：Professor Bhushan L. Karihaloo is currently the Head of Research Institute ofTheoretical, Applied and Computational Mechanics at Cardiff University. Prior to this position, he held chairs at Aalborg University, Denmark (February 1996 - June 1997), The University of Sydney (February 1986 - February 1996), and The University of Newcastle (October 1983 - February 1986), Australia.Professor Karihaloo has made remarkable contributions to many areas of mechanics, including optimum design of structures made from traditional and advanced composite materials (some of his earliest pioneering papers have now becomeclassics), theoretical fracture mechanics, especially non-planar crack growth which has had the most scientific impact, fracture of quasi-brittle materials, in particular of concrete and fibre-reinforced cementitious composites, micro-mechanics of transformation toughening of zirconia-based ceramics which have helped in the development of tough advanced engineering ceramics, and development of nano-structured materials with unusual mechanical and physical properties. For his continuing contributions, Professor Karihaloo has received many awards and honours. In 2006, he was awarded the very prestigious Griffith Medal ofThe European Structural Integrity Society (2006) for outstanding contributions to Theoretical Fracture Mechanics and Fracture of quasi-brittle materials.He is Honorary Fellow of Czech Society of Mechanics of The Czech Academy of Sciences (1989) for contributions to Structural Optimization and Fracture Mechanics, Honorary Fellow of International Congress on Fracture (2001) for lasting contributions to Fracture Mechanics. He was awarded DSc (Honoris Causa) by St Petersburg University, Russia (2007), and DSc by The University of Sydney. Professor Karihaloo’s international esteem is also demonstrated by his service to the international mechanics community. Among the numerous positions he has held, he is Editor-in-Chief (together with Professor R O Ritchie, UC Berkeley and Dr I Milne) of the recent 10-Volume Comprehensive Reference Work on Structural Integrity, Elsevier, 2003, which was awarded the Best Reference Prize in 2004 by the American Society for Engineering Education. Professor Karihaloo is Member of Editorial Board of 9 International Journals, Associate Editor of Mechanics of Materials and of the International Journal of Fracture. He is Vice-President, International Congress on Fracture, ICF (1997 – 2001, 2005 - ), Chair, The Royal Society UK National Panel of IUTAM (2005 - ), and Member of Congress Committee, International Union of Theoretical and Applied Mechanics, IUTAM (1994 - 96, 2000 - ). Professor Karihaloo has been Chairman and/or Member of Scientific Committees of many International Congresses/Conferences/ Symposia. He has been invited to give keynote/invited talks at numerous International Congresses/Conferences/Symposia.主持人注：Karihaloo教授是国际固体力学领域知名学者、在英国相当于中国力学学会主席、IUTAM大会委员会委员（全球只有36人），与我国许多知名教授、院士等十分熟悉。

17:18

“总理救我”

One women posted it on last Friday when she struggled at her life for her right near the new location of CCTV tower. At least, our nation does not take care of her children well enough. When can we have a 'government of the people, by the people, for the people' ???

14:09

4月5日
happiness

What is the happiness? and what's the key of feeling happy? totally confused or totally understand . In my opinion, happiness crashes into yourself just because you feel satisfied with yourself, with what you have done, what you think, and what you have. Never let your hope goes far beyond your ability or what you can expect to get. Maybe I have that idea because I am not ambitious. In chinese words, I am not highly orientated. Anyway, I am not willing to stuggle to become the guy of type which I or somebody else images or want me to be in 10 or 20 years. I am just me today. I am always quit satisfied with me yesterday and I only want me tomorrow to be slightly better than me today. Just as 宝钗 or someone else in 红楼梦, who I cannot remember exactly, says: 郁郁着一天是一天， 快乐着一天也是一天。 Lin Qingxuan, a taiwanesse writer, also says: 快乐着活在当下。痛并快乐着，既然不能避免痛苦，何不将快乐放大，痛苦自然生存的空间就很小了。。。

PS: today is Qingming festival, the day for memory of people who passed away! bless for people who have gone and also who are still seeking his/her happiness~~~ a little weird....

8:34

4月3日
paper accepted

being informed tonight... but still have to do some modification,esp. on the typeset...
at the starting point of learning le Francais, endeavoring....
many things pending to work on... coding on QDD, reading papers, attending seminars, playing badminton and in-line skating (has been being planned so long )

23:00

3月24日
Coloquium to be attended

3月27日工学院力学与空天技术系学术报告
报告题目
Part A: Phononic band gaps of elastic periodic structures: a homogenization theory study
Part B: A microfluidic nanoliter mixer with grooved structures driven by capillary pumping
报告人 Chien C. Chang（张建成）
Professor, Institute of Applied Mechanics, National Taiwan University
Research Fellow and Executive Director, Center for Mechanics, Research Center
for Applied Sciences, Academia Sinica, Taiwan

主持人： 苏先樾 教授

时 间：3月27日（周二）下午2:30点

地 点：北京大学力学楼四层434会议室


欢迎广大师生光临！要求力学系研究生必须参加。
联系人：刘才山，62756177
Abstract：
Part A: In this talk, we examine the band structures of phononic crystals with particular emphasis on the effects of the mass density ratio and of the contrast of elastic constants. The phononic crystals consist of arrays of different media embedded in a rubber or epoxy. It is shown that the density ratio rather than the contrast of elastic constants is the dominant factor that opens up phononic band gaps. The physical background of this observation is explained by applying the theory of homogenization to investigate the group velocities of the low-frequency bands at the center of symmetry of the first Brillouin zone. The theory is first illustrated for one-dimensional layered structures, which is simple and easy to understand. The two- and three-dimensional theory establishes a more sophisticated connection between the fine periodic microstructures and the group velocities of the lowest-frequency dispersion. Interesting comparisons will be made with band gaps of photonic materials in which the composed materials have different dielectric constants.
Part B: In this talk, I will describe a nano-liter mixer fully driven by capillary force, and explain its mechanics. It is known that surface tension-capillary pumping is an effective driving force in a microchannel, however a power-free mixer that uses only surface tension has not yet been achieved. In the present study, a power-free method is explored to perform mixing in a microchannel without any external active mechanisms such as pumps, valves or external energies like electrostatic or magnetic fields. The mixer is cost effective as the channel is designed to have no sidewalls with the liquid being confined to flow between a bottom hydrophilic stripe and a top-covered hydrophobic substrate. It is found from both theoretical analysis and experiments that for a given channel width, the flow rate solely due to capillary pumping can be maximized at an optimal channel height. The flow rate is in the order of nanoliters per second, for example, the flow rate is 0.65 nL s(-1) at the optimal channel height 13 mu m, given the channel width 100 mu m. It is most crucial to this power-free mixing device that two liquid species must be well mixed before the liquids are transported to exit to a reservoir. For this purpose, asymmetric staggered grooved cavities are optimally arranged on the bottom substrate of the channel to help mixing two different liquid species. It is shown that maximum mixing occurs when the depth of the grooved structures is about two-thirds of the total channel height.

Biography：
Ph.D. Mathematics, University of California, Berkeley (1985)
M.S. Applied Mechanics, National Taiwan University (1982)
B.S. Chemical Engineering, National Taiwan University (1980)
Fields of Interest: Multi-scale Mechanics; Photonics and Plasmonics, Biomedical Mechanics, Multi-body Fluid Mechanics

11:07

3月23日
colloquia attended

北京大学工学院联合学术报告（力学与空天技术系、能源与资源工程系）报告一：Vibrodynamics of ‘solid+fluid’By Professor V.A.Vladimirov,University of York, UK报告二：Modeling of reactive fluid flow and geochemical transport in geological mediaBy Tianfu Xu, Earth Sciences Division, Lawrence Berkeley National Laboratory

报告一摘要：
Vibrational mechanics (vibromechanics) is an active interdisciplinary research area that is closely linked to engineering and many other applied subjects. It studies the motions of various mechanical systems in the presence of high frequency oscillations of their parameters. This lecture is devoted to the vibromechanics of dynamical systems composed of solids and a fluid (`solid+fluid') with the use of the averaging method. First we present the averaging procedure in two forms. For the achieving of maximal transparency we consider the most celebrated example of a pendulum with a vibrating pivot (the Stephenson – Kapitza pendulum). The first form of the averaging procedure operates with the exact governing equations. The second form directly uses the least action principle, in which the averaging procedure appears naturally and the conservation laws follow automatically. The presented results provide the full model for both ‘fast’ and ‘slow’ motions. The main advantage of the ‘least action’ form of the procedure is the substantial reduction in the analytical calculations, which are typically cumbersome for the asymptotic methods. In the second part of the lecture we apply the least action form of the averaging procedure to the dynamics of a solid in an inviscid incompressible fluid that fills a vibrating vessel of an arbitrary shape. The solid can be either homogeneous or inhomogeneous in density. The results include equations for ‘slow’ motions, ‘slow Lagrangian’, the ‘slow energy' and a ‘vibrogenic force’, exerted by a fluid into a solid. The case of N homogeneous solids is also outlined. We describe our calculations, present results in an accessible form, and discuss related examples, properties, and conjectures. The examples of either homogeneous or inhomogeneous spherical solid are considered in details. The connection to the viscous ‘steady streaming theory’ is clarified.

报告二摘要：
A comprehensive coupled program TOUGHREACT for multiphase fluid and heat flow, solute transport, and geochemical processes has been developed at Lawrence Berkeley National laboratory (LBNL), which is widely used for geological and environmental problems. A brief overview of this modeling capability will be given. Several application examples will be used to illustrate the applicability. First example is related to CO2 geological sequestration. CO2 is co-injected with either H2S or SO2 into a Gulf Coast sandstone. Changes in water chemistry, mineral dissolution and precipitation, and amounts of CO2 hydrodynamic, solubility, and mineral trapping are studied using the program. Other examples, dealing with nuclear waste geological disposal, mineral scaling and changes in porosity and permeability in a geothermal field, and environmental and groundwater quality problems, will be also presented.

17:59

3月23号
F1 new season started

these days being busy with learning linux...so, it's a little late to post this...Schumi left, but Kimi still there, support Kimi and his Ferrari