A fractional step scheme with modified characteristic finite differences run- ning in a parallel arithmetic is presented to simulate a nonlinear percolation system of multilayer dynamics of fluids in a porous medium w...A fractional step scheme with modified characteristic finite differences run- ning in a parallel arithmetic is presented to simulate a nonlinear percolation system of multilayer dynamics of fluids in a porous medium with moving boundary values. With the help of theoretical techniques including the change of regions, piecewise threefold quadratic interpolation, calculus of variations, multiplicative commutation rule of differ- ence operators, multiplicative commutation rule of difference operators, decomposition of high order difference operators, induction hypothesis, and prior estimates, an optimal order in 12 norm is displayed to complete the convergence analysis of the numerical algo- rithm. Some numerical results arising in the actual simulation of migration-accumulation of oil resources by this method are listed in the last section.展开更多
联合采用感官分析、香气活性成分定性与定量技术,对茅台镇和神农架产区酱酒的香气感官特征及香气组分特征进行解析。感官分析表明茅台镇酱酒主要表现为曲香、粮香、酱香等香气特征,神农架酱酒则主要表现为甜香、酱香、青草香、酸香等香...联合采用感官分析、香气活性成分定性与定量技术,对茅台镇和神农架产区酱酒的香气感官特征及香气组分特征进行解析。感官分析表明茅台镇酱酒主要表现为曲香、粮香、酱香等香气特征,神农架酱酒则主要表现为甜香、酱香、青草香、酸香等香气特征。采用香气萃取物稀释分析技术从2个产区酱香型白酒中筛选出133种挥发性物质(香气稀释因子≥2);基于多组分的定量结果结合香气活度值(odor activity value,OAV)与偏最小二乘判别分析,从2个产区酱酒中共挖掘出65个重要香气化合物(OAV>1)以及32个差异性化合物[即变量权重重要性排序(variable importance for the projection,VIP)≥1];进一步明确了2个不同产区酱酒的香气感官特征与香气化合物之间的联系。结果表明,与茅台镇酱酒感官特征相关的重要香气化合物主要包括2,3,5-三甲基吡嗪、2-乙基-3,5-二甲基吡嗪、2-乙基-5-甲基吡嗪、2,6-二甲基吡嗪、2-甲基丁酸乙酯、己酸乙酯、乳酸乙酯、γ-丁内酯、苯丙酸乙酯、异戊酸乙酯;与神农架酱酒感官特征相关的重要香气物质为甲硫醇、2,6-二乙基吡嗪、2-乙基-6-甲基吡嗪、3-甲硫基丙醛、香草醛、2,3-丁二酮、γ-壬内酯、3-羟基-2-丁酮、乙醛、乙缩醛、己醛、异戊醛。该研究通过剖析两类酱香型白酒的香气轮廓与风味特征,增进了对2个产区酱酒风味独特性的认识,为生产品质控制提供了参考和理论依据。展开更多
This paper extends the classical covariant deriva tive to the generalized covariant derivative on curved sur faces. The basement for the extension is similar to the pre vious paper, i.e., the axiom of the covariant fo...This paper extends the classical covariant deriva tive to the generalized covariant derivative on curved sur faces. The basement for the extension is similar to the pre vious paper, i.e., the axiom of the covariant form invariabil ity. Based on the generalized covariant derivative, a covari ant differential transformation group with orthogonal duality is set up. Through such orthogonal duality, tensor analy sis on curved surfaces is simplified intensively. Under the covariant differential transformation group, the differential invariabilities and integral invariabilities are constructed on curved surfaces.展开更多
The extreme temperature differences in flat steel box girder of a cable-stayed bridge were studied.Firstly,by using the long-term measurement data collected by the structural health monitoring system installed on the ...The extreme temperature differences in flat steel box girder of a cable-stayed bridge were studied.Firstly,by using the long-term measurement data collected by the structural health monitoring system installed on the Runyang Cable-stayed Bridge,the daily variations as well as seasonal ones of measured temperature differences in the box girder cross-section area were summarized.The probability distribution models of temperature differences were further established and the extreme temperature differences were estimated with a return period of 100 years.Finally,the temperature difference models in cross-section area were proposed for bridge thermal design.The results show that horizontal temperature differences in top plate and vertical temperature differences between top plate and bottom plate are considerable.All the positive and negative temperature differences can be described by the weighted sum of two Weibull distributions.The maximum positive and negative horizontal temperature differences in top plate are 10.30°C and13.80°C,respectively.And the maximum positive and negative vertical temperature differences between top plate and bottom plate are 17.30°C and 3.70°C,respectively.For bridge thermal design,there are two vertical temperature difference models between top plate and bottom plate,and six horizontal temperature difference models in top plate.展开更多
基金Project supported by the Major State Basic Research Program of China (No. 19990328)the National Tackling Key Problems Program (No. 20050200069)+4 种基金the National Natural Science Foundation of China (Nos. 10771124, 10372052, 11101244, and 11271231)the Doctorate Foundation of the Ministry of Education of China (No. 20030422047)the Shandong Province Natural Science Foundation (No. ZR2009AQ012)the Independent Innovation Foundation of Shandong University(No. 2010TS031)the Scientific Research Award Fund for Excellent Middle-Aged and Young Scientists of Shandong Province (No. BS2009NJ003)
文摘A fractional step scheme with modified characteristic finite differences run- ning in a parallel arithmetic is presented to simulate a nonlinear percolation system of multilayer dynamics of fluids in a porous medium with moving boundary values. With the help of theoretical techniques including the change of regions, piecewise threefold quadratic interpolation, calculus of variations, multiplicative commutation rule of differ- ence operators, multiplicative commutation rule of difference operators, decomposition of high order difference operators, induction hypothesis, and prior estimates, an optimal order in 12 norm is displayed to complete the convergence analysis of the numerical algo- rithm. Some numerical results arising in the actual simulation of migration-accumulation of oil resources by this method are listed in the last section.
文摘联合采用感官分析、香气活性成分定性与定量技术,对茅台镇和神农架产区酱酒的香气感官特征及香气组分特征进行解析。感官分析表明茅台镇酱酒主要表现为曲香、粮香、酱香等香气特征,神农架酱酒则主要表现为甜香、酱香、青草香、酸香等香气特征。采用香气萃取物稀释分析技术从2个产区酱香型白酒中筛选出133种挥发性物质(香气稀释因子≥2);基于多组分的定量结果结合香气活度值(odor activity value,OAV)与偏最小二乘判别分析,从2个产区酱酒中共挖掘出65个重要香气化合物(OAV>1)以及32个差异性化合物[即变量权重重要性排序(variable importance for the projection,VIP)≥1];进一步明确了2个不同产区酱酒的香气感官特征与香气化合物之间的联系。结果表明,与茅台镇酱酒感官特征相关的重要香气化合物主要包括2,3,5-三甲基吡嗪、2-乙基-3,5-二甲基吡嗪、2-乙基-5-甲基吡嗪、2,6-二甲基吡嗪、2-甲基丁酸乙酯、己酸乙酯、乳酸乙酯、γ-丁内酯、苯丙酸乙酯、异戊酸乙酯;与神农架酱酒感官特征相关的重要香气物质为甲硫醇、2,6-二乙基吡嗪、2-乙基-6-甲基吡嗪、3-甲硫基丙醛、香草醛、2,3-丁二酮、γ-壬内酯、3-羟基-2-丁酮、乙醛、乙缩醛、己醛、异戊醛。该研究通过剖析两类酱香型白酒的香气轮廓与风味特征,增进了对2个产区酱酒风味独特性的认识,为生产品质控制提供了参考和理论依据。
基金supported by the NSFC(11072125 and 11272175)the NSF of Jiangsu Province(SBK201140044)the Specialized Research Fund for Doctoral Program of Higher Education(20130002110044)
文摘This paper extends the classical covariant deriva tive to the generalized covariant derivative on curved sur faces. The basement for the extension is similar to the pre vious paper, i.e., the axiom of the covariant form invariabil ity. Based on the generalized covariant derivative, a covari ant differential transformation group with orthogonal duality is set up. Through such orthogonal duality, tensor analy sis on curved surfaces is simplified intensively. Under the covariant differential transformation group, the differential invariabilities and integral invariabilities are constructed on curved surfaces.
基金Project(51178100)supported by the National Natural Science Foundation of ChinaProject(1105007001)supported by the Foundation of the Priority Academic Development Program of Higher Education Institute of Jiangsu Province,ChinaProject(3205001205)supported by the Teaching and Research Foundation for Excellent Young Teachers of Southeast University,China
文摘The extreme temperature differences in flat steel box girder of a cable-stayed bridge were studied.Firstly,by using the long-term measurement data collected by the structural health monitoring system installed on the Runyang Cable-stayed Bridge,the daily variations as well as seasonal ones of measured temperature differences in the box girder cross-section area were summarized.The probability distribution models of temperature differences were further established and the extreme temperature differences were estimated with a return period of 100 years.Finally,the temperature difference models in cross-section area were proposed for bridge thermal design.The results show that horizontal temperature differences in top plate and vertical temperature differences between top plate and bottom plate are considerable.All the positive and negative temperature differences can be described by the weighted sum of two Weibull distributions.The maximum positive and negative horizontal temperature differences in top plate are 10.30°C and13.80°C,respectively.And the maximum positive and negative vertical temperature differences between top plate and bottom plate are 17.30°C and 3.70°C,respectively.For bridge thermal design,there are two vertical temperature difference models between top plate and bottom plate,and six horizontal temperature difference models in top plate.
文摘利用2005年1月至2017年12月搭载在美国环境监测Aura卫星上的臭氧监测仪(Ozone Monitoring Instrument,OMI)数据和NCEP气象资料,在夏季风环流指数定义方法的基础上,重新定义了南亚区域冬季风环流指数,并分别计算了南亚夏季风和冬季风环流指数.结合冬夏两季环流的强弱变化采用相关分析、合成分析和奇异值分解(Singular Value Decomposition,SVD)等方法,探讨了环流异常形势下臭氧的时空变化特征.结果表明:(1)南亚夏季纬向环流与经向环流的强度变化存在一致性,冬季经向环流与纬向环流的强度变化差异较大.(2)南亚臭氧柱总量的季节变化明显,且近13年来臭氧柱总量整体呈上升趋势.(3)夏季(冬季)风环流指数与对流层中低(中高)层和平流层中低层臭氧的相关性显著,但夏季平流层和对流层的相关趋势相反.(4)夏季风环流增强对应青藏高原-伊朗高原上空及南侧区域的上升运动增强,对臭氧的输送作用是造成对流层臭氧分布呈现差异的原因.(5)冬季风环流强弱期的垂直上升和下沉运动中心的移动,以及南北向、东西向气流交汇区的差异是造成臭氧分布不同的原因.