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1.
THELINEARBI-SPATIALTENSOREQUATIONφ_(ij)A ̄iXB ̄j=CChenYuming(陈玉明),XiaoHeng(肖衡),LiJianbo(李建波)(DepartmentofAppliedMathematics,Hun...  相似文献   

2.
张双寅 《力学进展》1998,28(4):553-553
ChandlerCFulton和HuajianGao教授所写“压电陶瓷断裂中的非线性”(Electricanonlineaxityinfractureofpiezoelectricceramics,ApplMechRev,1997,50(11):56~63)是一篇很好的文章.它巧妙地将电场与力学场非线性分开处理,提出多尺度模型,得出了改进的预测结果,很有启发性.压电陶瓷(包括铁电材料)作为机敏结构(smartstructures)的传感器与驱动器正在得到日益广泛的应用.然而,由于对此类材料的断裂行为缺乏深入了解,其断裂力学理论很不成熟,因而此种结构的可靠性尚不能得到保证.近年来已建立了压电材料的线性断裂力学…  相似文献   

3.
????? 《力学与实践》1996,18(2):63-64
σ_(r4)在应力圆上的几何表示萧敬勋(河北工学院,天津300130)第四强度理论与第三强度理论计算结果的差异问题,一向被人们所关注.一般人们在主应力空间用立体几何图形来表示其差异I‘1,或在平面应力状态下(σ3=0),于σ1,σ2平面上用平面几何图?..  相似文献   

4.
The present investigation is concerned with an axi-symmetric problem in the electromagnetic micropolar thermoelastic half-space whose surface is subjected to the mechanical or thermal source. Laplace and Hankel transform techniques are used to solve the problem. Various types of sources are taken to illustrate the utility of the approach. Integral transforms are inverted by using a numerical technique to obtain the components of stresses, temperature distribution, and induced electric and magnetic fields. The expressions of these quantities are illustrated graphically to depict the magnetic effect for two different generalized thermoelasticity theories, i.e., Lord and Shulman (L-S theory) and Green and Lindsay (G-L theory). Some particular interesting cases are also deduced from the present investigation.  相似文献   

5.
结构力学教材中δ_(ij(i≠j))=0的主振型问题   总被引:2,自引:0,他引:2  
本文对振动方程副系数δij(i≠j)不等于零的振动体系从线性代数矩阵秩的判断,并结合实例分析,给出解并绘振型图  相似文献   

6.
Consideringthehigherdimensionalperiodicsystemswithdelayoftheformx′(t)=A(t,x(t))x(t)+f(t,x(t-τ)),(1)x′(t)=gradG(x(t))+f(t,x(t-...  相似文献   

7.
ConsidertheCauchyproblemforthewaveequationinRN×R+(N≥2):2u(x,t)t2-xiaij(x)xju=|u|p-1·u  ((x,t)∈RN×(0,T)),u(x,0)=g(x) (x∈RN),ut(x,0)=h(x) (x∈RN),(1)whereu(x,t)isnontrivialsolutionwithfinitespeedofpropagationandissupportedonaforwardcone(x,t)·t≥0,|…  相似文献   

8.
本文研究偏微方程δ/δt(a(t)δ/δu(x,t)+m(t)δu(x,t)/δt+c1(x,t,u(x,t)+c2(x,t,u,t-τ))=∫^ta∑^tj=1(t,ζ)△u(x,hj(t,ζ)dσ(ζ)+f(x,t)的振动性,给出了方程(1)振动的一些充分条件。  相似文献   

9.
Someengineeringproblemscanbeexpressedbysuchasystemoflinearnon_homogeneousdifferentialequationsasL1[u1(q)]=F1(q),L2[u2(q)]=F2(q)+f2[u1(q)],…Ln[un(q)]=Fn(q)+fn[u1(q),u2(q),…,un-1(q)],(1)andtheirinitialandboundaryconditions,whereqisthesetofallargumentsw…  相似文献   

10.
本文通过构造Liapunov泛函,给出了一严二维非线性时滞动力系统{x(t)=y(t);y(t)=-p(x(t))-q(y(t))+∫-^0K(x(t+s))y(t+s)ds+f(t)的运动稳定性、有界性、周期运动的存在性和平稳振荡的存在性的几个定理,并给出了时滞范围的简明表达式。  相似文献   

11.
Sol-gel-derived nano-powders of lead magnesium niobate and lead titanate solid solutions (PMN-PT or PMNT) were prepared from lead acetate trihydrate (Pb(CH3COO)2·3H2O), magnesium acetate trihydrate (Mg(CH3COO)2·3H2O), niobium ethoxide (Nb(OC2H5)5) and titanium isopropoxide (Ti(OCH(CH3)2)4). The key steps in the preparation process were discussed, The crystalline phases in the powders were investigated using X-ray diffraction (XRD) analysis and the size of grains was observed by field-emission scanning electron microscopy (SEM). These powders, with good dispersion characteristics and narrow grain size distribution (ranging from 50 nm to 200 nm), may be used to prepare PMNT thick films and ceramics.  相似文献   

12.
吴承康 《力学进展》2001,31(4):630-631
引言国际等离子体化学会议(International Symposium on Plasma Chemistry, ISPC)开始于1973年,由国际纯粹与应用化学联合会(IUPAC)主办,由其下属物理化学部等离子体化学分委员会具体组织.历届会议的会址是德国Kiel (1973),意大利罗马(1975),法国Limoge (1977),瑞士苏黎世(1979),英国爱丁堡(1981),加拿大Montreal (1983),荷兰Eindhoven (1985),日本东京(1987),意大利Pugno…  相似文献   

13.
WangShouxin(王守信);LiuXiping(刘喜平);PengTianguo(彭天国);ZhaoZhongsheng(赵忠生);ZhaoSuhua(赵素华)(ReceivedNov.11.1994;CommunicatedbyLinZong...  相似文献   

14.
由戴念祖、老亮著的《中国物理学史大系·力学史》已于2001年5月由湖南教育出版社出版.本书是“中国物理学史大系”(丛书,预计共10本,戴念祖是编委会主编)的第1本.内容是西方力学知识传入以前的中国力学史.各章名称为:前言;(一)引言;(二)简单机械;(三)重心和平衡;(四)时空和运动;(五)动力学知识;(六)流体;(七)固体;(八)材料力学;(九)振动;(十)基本计量;(十一)明清时期西方力学知识的传入和传统力学的终结;附录.正文前有彩图18幅. 本书可说是戴念祖《中国力学史》(河北教育出版社,…  相似文献   

15.
短纤维增强对聚碳酸酯非线性粘弹性性能的影响   总被引:1,自引:0,他引:1  
本文采用SHP B装置研究了聚碳酸酯和短玻璃纤维增强聚碳酸酯在10-4~103/秒应变率范围和有限应变条件下的非线性粘弹性力学行为。根据Coleman和Noll的材料本构关系理论和本文实验结果,提出聚碳酸酯的本构方程 m(e,(?))=E0e+e2+e3+E1 integral from n=0 to 1((?)exp(-(t-)/1)d)+E2 integral from n=0 to 1((?)exp(-(t-)/2)d+(?)) 并进而得到短纤维增强聚碳酸酯的一个相当简单的本构方程 frm=m(e,(?)) 在加卸载全过程,两种本构方程的理论计算值都能满意地与实验结果相一致。  相似文献   

16.
本文主要利用Brouwer不动点定理和解的交差化积的方法,研究下列周期Riccati型方程y=f(t,y)=A(t)y^m+B(t)y+C(t)(m≥2,m∈N)其中,A(t)、B(t)和C(t)均是以ω为周期的连续函数,ω〉0解的振动性渐近性,不仅得以了方程(**)的非振动解与其ω周期解之间的渐近关系,而且得到了方程(**)存在振动解的必要条件和充分条件。  相似文献   

17.
Yi Du  Dermot  O'Hare 《Particuology》2010,8(3):188-191
Layered α-cobalt hydroxides Co(OH1.65 Cl0.35.0.5H2O (1), Co(OH)1.75(NO3)0.25.0.1H2O(2) with unique macro- and microscale morphologies have been synthesised by a low temperature, ammonia-controlled vapour-diffusion method. The materials have thin film morphologies and were characterized by X-ray powder diffraction (XRD) and field emission scanning electron microscopy (FESEM).  相似文献   

18.
WewillconsiderthefollowingKuramoto_Sivashinskyequation[1,2]withobviousphysicalmeaningsandmechanicalmodels:ut+ε4ux4+2ux2+uux=0,(1)withtheinitialcondition:u(x,0)=φ(x),(2)andtheboundarycondition:u(-l,t)=u(l,t)=ux2(-l,t)=ux2(l,t)=0,(3a)orthebound…  相似文献   

19.
HanQiang(韩强);MaHongwei(马宏伟);ZhangShanyuan(张善元);YangGuitong(杨桂通);WuJike(武际可)(ReceivedNov.18.1994)THEDYNAMICBUCKLINGPROBLEMCAUS...  相似文献   

20.
Wehavediscussedconceptofequationwithn_turningpointsinmypaper[1],i.e.,asecondorderlinearordinarydifferentialequationd2ydx2+[λ2q1(x)+λq2(x,λ)]y=0,whereq1(x)=(x-μ1)(x-μ2)…(x-μn)f(x),f(x)≠0,andλisalargeparameter.Althroughthefirsttermoftheasymptoticexpan…  相似文献   

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