Numerical simulations were performed on flow and heat transfer performances of heat exchangers having six helical baffles of different baffle shapes and assembly configurations, i.e., two trisection baffle schemes, tw...Numerical simulations were performed on flow and heat transfer performances of heat exchangers having six helical baffles of different baffle shapes and assembly configurations, i.e., two trisection baffle schemes, two quadrant baffle schemes, and two continuous helical baffle schemes. The temperature contour or the pressure contour and velocity contour plots with superimposed velocity vectors on meridian, transverse and unfolded concentric hexagonal slices are presented to obtain a full angular view. For the six helix baffled heat exchangers,the different patterns of the single vortex secondary flow and the shortcut leakage flow were depicted as well as the heat transfer properties were compared. The results show that the optimum scheme among the six configurations is a circumferential overlap trisection helix baffled heat exchanger with a baffle incline angle of 20°(20°TCO) scheme with an anti-shortcut baffle structure, which exhibits the second highest pressure dropΔpo, the highest overall heat transfer coefficient K, shell-side heat transfer coefficient hoand shell-side average comprehensive index ho/Δpo.展开更多
Propagation criteria and resiliency of vectorial Boolean functions are important for cryptographic purpose(see [1-4,7,8,10,11,16]).Kurosawa,Stoh [8] and Carlet [1] gave a construction of Boolean functions satisfying P...Propagation criteria and resiliency of vectorial Boolean functions are important for cryptographic purpose(see [1-4,7,8,10,11,16]).Kurosawa,Stoh [8] and Carlet [1] gave a construction of Boolean functions satisfying PC(l) of order k from binary linear or nonlinear codes.In this paper,the algebraic-geometric codes over GF(2m) are used to modify the Carlet and Kurosawa-Satoh's construction for giving vectorial resilient Boolean functions satisfying PC(l) of order k criterion.This new construction is compared with previously known results.展开更多
In this article, we test the nature of X（3872）, which is assumed to be a P-wave [cq]-scalar-diquark [cq]- axial-vector-antidiquark tetraquark state with JP = 2^-. The interpolating current representing the JP = 2^- ...In this article, we test the nature of X（3872）, which is assumed to be a P-wave [cq]-scalar-diquark [cq]- axial-vector-antidiquark tetraquark state with JP = 2^-. The interpolating current representing the JP = 2^- state is proposed. Technically, contributions of the operators up to dimension six are included in the operator product expansion. The mass obtained for such state is m2- = （4.38±0.15） GeV. We conclude that it is impossible to describe the X（3872） structure as JV = 2^- tetraauark state.展开更多
基金Supported by the National Natural Science Foundation of China(50976022,51276035)the Provincial Science and Technology Innovation and Transformation of Achievements of Special Fund Project of Jiangsu Province(BY2011155)
文摘Numerical simulations were performed on flow and heat transfer performances of heat exchangers having six helical baffles of different baffle shapes and assembly configurations, i.e., two trisection baffle schemes, two quadrant baffle schemes, and two continuous helical baffle schemes. The temperature contour or the pressure contour and velocity contour plots with superimposed velocity vectors on meridian, transverse and unfolded concentric hexagonal slices are presented to obtain a full angular view. For the six helix baffled heat exchangers,the different patterns of the single vortex secondary flow and the shortcut leakage flow were depicted as well as the heat transfer properties were compared. The results show that the optimum scheme among the six configurations is a circumferential overlap trisection helix baffled heat exchanger with a baffle incline angle of 20°(20°TCO) scheme with an anti-shortcut baffle structure, which exhibits the second highest pressure dropΔpo, the highest overall heat transfer coefficient K, shell-side heat transfer coefficient hoand shell-side average comprehensive index ho/Δpo.
基金Project supported by the National Natural Science Foundation of China (No.10871068)the joint grant of the Danish National Research Foundation and the National Natural Science Foundation of China and the Shanghai Leading Academic Discipline Project (No.S30504)
文摘Propagation criteria and resiliency of vectorial Boolean functions are important for cryptographic purpose(see [1-4,7,8,10,11,16]).Kurosawa,Stoh [8] and Carlet [1] gave a construction of Boolean functions satisfying PC(l) of order k from binary linear or nonlinear codes.In this paper,the algebraic-geometric codes over GF(2m) are used to modify the Carlet and Kurosawa-Satoh's construction for giving vectorial resilient Boolean functions satisfying PC(l) of order k criterion.This new construction is compared with previously known results.
基金Supported by the National Natural Science Foundation of China under Grant Nos. 10975184,11047117,11105222,and 11105223
文摘In this article, we test the nature of X（3872）, which is assumed to be a P-wave [cq]-scalar-diquark [cq]- axial-vector-antidiquark tetraquark state with JP = 2^-. The interpolating current representing the JP = 2^- state is proposed. Technically, contributions of the operators up to dimension six are included in the operator product expansion. The mass obtained for such state is m2- = （4.38±0.15） GeV. We conclude that it is impossible to describe the X（3872） structure as JV = 2^- tetraauark state.
