Experimental study on temperature stress calculation and temperature control optimization of concrete based on early age parameters

Temperature control curve is the key to achieving temperature control and crack prevention of high concrete dam during construction,and its rationality depends on the accurate measurement of temperature stress.With the simulation testing machine for the temperature stress,in the present study,we carried out the deformation process tests of concrete under three temperature curves：convex,straight and concave.Besides,we not only measured the early-age elastic modulus,creep parameters and stress process,but also proposed the preferred type.The results show that at early age,higher temperature always leads to greater elastic modulus and smaller creep.However,the traditional indoor experiments have underestimated the elastic modulus and creep development at early age,which makes the calculated value of temperature stress too small,thus increasing the cracking risk.In this study,the stress values of the three curves calculated based on the strain and early-age parameters are in good agreement with the temperature stress measured by the temperature stress testing machine,which verifies the method accuracy.When the temperature changes along the concave curve,the law of stress development is in consistent with that of strength.Under this condition,the stress fluctuation is small and the crack prevention safety of the concave type is higher,so the concave type is better.The test results provide a reliable basis and support for temperature control curve design and optimization of concrete dams.     

氯苯甲酸生物降解及环境影响研究进展

I.IntroductionChlorobenzoic acids(CBAs)have been released to the envi-ronment intentionally due to their use in agriculture asherbicides,or unintentionally due to the function,they playedin the aerobic transformation of many chlorinated pollutants,such as polychlorinated biphenyls(PCBs)and alkyl benzenes.Moreover,chlorobenzoic acids are the major intermediate prod-ucts of aerobic catabolism of PCBs and one of the rate-limitingsteps in the overall PCBs degradation process.Degradation ofchl…     

APPLICATION OF QUADRATIC AND CUBIC TURBULENCE MODELS ON CAVITATING FLOWS AROUND SUBMERGED OBJECTS

Quadratic and cubic Non-Linear Eddy-Viscosity Models(NLEVMs) at low Reynolds number correction were introduced into the present Computational Fluid Dynamics(CFD) framework,to provide better numerical treatment about the anisotropic turbulence stress in cavitating flows,which have large density ratio and large-scaled swirling flow structures.The applications of these NLEVMs were carried out through a self-developed cavitation code,coupled with a cavitation model based on the transport equation of liquid phase.These NLEVMs were firstly validated by the benchmark of disk supercavity,and found able to obtain more accurate capture of the hydrodynamic properties than the linear models.One of such models was further applied on the cavitation problem of submerged vehicles.Ultimately,the supercavitating flows around an especially designed underwater vehicle were predicted using the cubic turbulence model,and its cavitation behaviors were studied.     

Measures to Strengthen Regulation of Accounting

随着我国财务管理体系和会计制度的改革,企事业单位对本单位会计核算和管理具有了更大自主权,如何正确运用和行使这些权力,实施有效的会计监督,是保障各单位领导正当行使其理财和核算自主权的重要手段     

NUMERICAL INVESTIGATION ON FLOW CHARACTERISTICS IN RIBBED BEND

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｇａｓ ｐａｒｔｉｃｌｅｆｌｏｗｉｎｃｕｒｖｅｄｄｕｃｔｓｈａｖｅｂｅｅｎｗｉｄｅｌｙａｐｐｌｉｅｄｉｎｅｎｇｉｎｅｅｒｉｎｇ .Ｒｅｓｅａｒｃｈ[2 ] ｓｈｏｗｓｔｈａｔｔｈｅｅｒｏｓｉｏｎｅｆｆｉｃｉｅｎｃｙｏｆｂｅｎｄｉｓ 5 0ｔｉｍｅｓｈｉｇｈｅｒｔｈａｎｔｈａｔｏｆｓｔｒａｉｇｈｔｐｉｐｅ .Ｔｈｅｒｅｆｏｒｅ ,ｉｍｐｒｏｖｉｎｇｔｈｅａｂｉｌｉｔｙｏｆｂｅｎｄｅｒｏｓｉｏｎｐｒｏｔｅｃｔｉｏｎｉｓａｎｕｒｇｅｎｔｔａｓｋ .Ｔｈｅｐｒｅｖｉｏｕｓｒｅｓｅａｒｃ…     

Research on the Sustainable Development of Chinese Small and Medium-Sized Enterprises - Construction and Application of R＆D Strategic Alliance

R ＆D strategic alliance is important for enterprises＇ sustainable development and it is a worth research for us. This paper firstly analyzes the condition and situation of tho small and medium-sized enterprises＇ strategic alliance. Then it points out that the small and medium-sized enterprises should choose a sttieable alliance organization, ally themselves with big enterprises, strive for the support of the government, and develop their technology through technology unions. Finally, it suggests that the government should create better innovation environment for R＆D strategic, alliance. A new way is also put forward for the applicotion and foundation of the small and medium-sized enterprises ＇ R＆D ,strategic alliance in China. It is also helpful for the sustainable development of small and medium-sized enterprises.     

我国股票市场的系统流动性实证研究

1997年的亚洲金融危机显示出个股的流动性受到市场因素的强烈影响,市场微观结构的研究开始更多地关注市场的系统性因素.本文以上海证券交易所全部A股的日交易数据为样本,证实了我国大陆股市存在系统流动性,与美国、香港股市相比,这一因素的影响更显著;根据流通股每年的流通市值分组检验,发现我国大陆股市与香港股市相似,存在着"倒U"形态的规模效应;与发达股票市场不同,我国股市系统流动性的显著性比例与流通市值无明显的单调关系.     

SEMI-ADAPTIVE GRID METHOD FOR CONVECTION-DOMINATED FLOW

A simple and efficient adaptive grid method (so-called "semi-adaptive grid method" ,SAGM) is presented in the paper. An obvious speciality of this method is that all computations are carried out on the physical plane. This semi-adaptive grid method has been successfully applied to solve the problems of steady and unsteady convection-diffusion equations with convection-dominated. A various examples have been tested. The numerical results show that numerical solutions are monotonic (near boundary or shock layer). The accuracy is higher than that on the uniform meshes.     

以创新促进无锡经济又快又好发展

过去的一年,是不平凡的一年。无锡市按照省委、省政府的部署和要求,在经济工作中突出重点,着力推进以搞好国有企业为中心的改革,加快股份制改造,促进股权多元化,使一批企业的活力明显增强;着力推进国有和集体经济的战略性改组,结合纺织压锭等措施,按照有所为、有所不为和有进有退原则,调整布局,优化结构,使一批企业增强了实力;着力推进科技创新、技术进步,增加技改投入,大力开发新品,使一批企业的竞争力和发展后劲有明显提高,１９９９年全市开发新品１０００多项,、其中１／３是高新技术产品。当前,宏观经济形势有利于加…