In my ten-yeat experience of tenching English as major in college , I feel that students experience more difficulties in listening lessons than in other lessons. What, then, prevents students from achieving success in...In my ten-yeat experience of tenching English as major in college , I feel that students experience more difficulties in listening lessons than in other lessons. What, then, prevents students from achieving success in the listening class? I suggest that anxiety is one of the major factors, which interferes with students listening comprehension. And I would agree with writers such as Gardner and Horwitz et al. (1991)that anxiety may impede learner’s ability to perform successfully in all aspects of learning a foreign language. I feet it is particularly significant for listening.展开更多
Thermal manikin plays important roles in simulating thethermal state of human bodies to facilitate the evaluationof thermal comfort properties of various clothing assem-blies.Based on the heat balance principle and an...Thermal manikin plays important roles in simulating thethermal state of human bodies to facilitate the evaluationof thermal comfort properties of various clothing assem-blies.Based on the heat balance principle and analysis ofrelated factors,the heat production rate of manikin isrecommended as an efficient evaluation index.Whereas,its inside heat production which occurs as a result of theexistence of temperature difference between its insidepart and outside surface,should not be ignored.Through a series of theoretical analysis and calculations,a compensative equation is deduced in this paper.展开更多
Since processing parameters have always been assumed to be stable in the current finite element numerical simulation of dieless drawing process, the simulation results for the product dimension tend to stabilize gradu...Since processing parameters have always been assumed to be stable in the current finite element numerical simulation of dieless drawing process, the simulation results for the product dimension tend to stabilize gradually. In fact, the dimension fluctuation exists in the forming process all the while. A mathematical model of Gauss distribution for processing parameters was employed and a finite element numerical model of dieless drawing process with non-steady processing parameters was established. Dieless drawing processing of Ni-Ti alloy wire was conducted for verifying the proposed model. The results indicated that the non-steady processing parameters model had higher simulation accuracy of the wire diameter than that given by the steady parameters model. Furthermore, the model could also be used to analyze the fluctuation characteristics in the whole dieless drawing process.展开更多
Some kinds of particular functions possessed by natural organisms are often formed by coupling up the multiple typical features on their body surfaces. Inspired by the coupling phenomenon in biological system, the med...Some kinds of particular functions possessed by natural organisms are often formed by coupling up the multiple typical features on their body surfaces. Inspired by the coupling phenomenon in biological system, the medium carbon steel specimens with the coupling effect of non-smooth mechanical property and microstructural features were fabricated by laser processing. Thermal fatigue behavior of specimens with biomimetic coupling surface was investigated and compared. The results confirmed that such a biomimetic method has the beneficial effect on improving the thermal fatigue property of medium carbon steel specimens. The related mechanisms behind the biomimetic coupling effect for explaining the enhanced thermal fatigue resistance were discussed preliminarily.展开更多
By means of a stochastic model suggested in this paper for the systems with local non-equilibrium excited thermal fluctuations, the famous Shannon entropy is extended to include the heat conduction processes controlle...By means of a stochastic model suggested in this paper for the systems with local non-equilibrium excited thermal fluctuations, the famous Shannon entropy is extended to include the heat conduction processes controlled externally by boundary constraints of constant temperature gradients at two sides.Meanwhile,using the description of master equation for the continuous Markov processes a balance equation of stochastic entropy production valid for one dimension gaseous heat conduction systems with high values of Prandtl number has been also established.Based on it,a general expression for both the stochastic entropy production and the entropy production of fluctuations have been further deduced by theΩ-expansions.In this formalism,all kinds of stochastic contributions to the dissipation from the non-equilibrium thermal fluctuation and internal noise turn explicit.展开更多
文摘In my ten-yeat experience of tenching English as major in college , I feel that students experience more difficulties in listening lessons than in other lessons. What, then, prevents students from achieving success in the listening class? I suggest that anxiety is one of the major factors, which interferes with students listening comprehension. And I would agree with writers such as Gardner and Horwitz et al. (1991)that anxiety may impede learner’s ability to perform successfully in all aspects of learning a foreign language. I feet it is particularly significant for listening.
文摘Thermal manikin plays important roles in simulating thethermal state of human bodies to facilitate the evaluationof thermal comfort properties of various clothing assem-blies.Based on the heat balance principle and analysis ofrelated factors,the heat production rate of manikin isrecommended as an efficient evaluation index.Whereas,its inside heat production which occurs as a result of theexistence of temperature difference between its insidepart and outside surface,should not be ignored.Through a series of theoretical analysis and calculations,a compensative equation is deduced in this paper.
基金National Basic Research Program of China (2006CB605200)National Natural Science Foundation of China (50634010, 50674008)Program for New Century Excellent Talents in University (NCET-06-0083)
文摘Since processing parameters have always been assumed to be stable in the current finite element numerical simulation of dieless drawing process, the simulation results for the product dimension tend to stabilize gradually. In fact, the dimension fluctuation exists in the forming process all the while. A mathematical model of Gauss distribution for processing parameters was employed and a finite element numerical model of dieless drawing process with non-steady processing parameters was established. Dieless drawing processing of Ni-Ti alloy wire was conducted for verifying the proposed model. The results indicated that the non-steady processing parameters model had higher simulation accuracy of the wire diameter than that given by the steady parameters model. Furthermore, the model could also be used to analyze the fluctuation characteristics in the whole dieless drawing process.
基金Supported by the Key Program of National Natural Science Foundation of China (Grant No. 50635030)Project 985-Automotive Engineering of Jilin University, International Cooperation key Project (Grant No. 2005DFA00850)Transfer Foundation of Scientific and Technical Fruits in Agriculture (Grant No. 2007GB23600467) of Ministry of Science and Technology of China
文摘Some kinds of particular functions possessed by natural organisms are often formed by coupling up the multiple typical features on their body surfaces. Inspired by the coupling phenomenon in biological system, the medium carbon steel specimens with the coupling effect of non-smooth mechanical property and microstructural features were fabricated by laser processing. Thermal fatigue behavior of specimens with biomimetic coupling surface was investigated and compared. The results confirmed that such a biomimetic method has the beneficial effect on improving the thermal fatigue property of medium carbon steel specimens. The related mechanisms behind the biomimetic coupling effect for explaining the enhanced thermal fatigue resistance were discussed preliminarily.
文摘By means of a stochastic model suggested in this paper for the systems with local non-equilibrium excited thermal fluctuations, the famous Shannon entropy is extended to include the heat conduction processes controlled externally by boundary constraints of constant temperature gradients at two sides.Meanwhile,using the description of master equation for the continuous Markov processes a balance equation of stochastic entropy production valid for one dimension gaseous heat conduction systems with high values of Prandtl number has been also established.Based on it,a general expression for both the stochastic entropy production and the entropy production of fluctuations have been further deduced by theΩ-expansions.In this formalism,all kinds of stochastic contributions to the dissipation from the non-equilibrium thermal fluctuation and internal noise turn explicit.
