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Science china(Physics,mechanics & Astronomy) 2010年第11期53卷 2103-2112页

作者： dong ming & zhou heng department of mechanics,tianjin {2.,tianjin 300072.china 1. department of mechanics Tianjin University Tianjin 300072 China

For hypersonic vehicles,as the temperature in its boundary layer usually exceeds 600 K,for which the molecular vibrational degree of freedom is excited,the perfect gas model is no longer *** this paper,the effect of high temperature induced variation of specific heat on the hypersonic turbulent boundary layer of flat plates is investigated by direct numerical simulations with the perfect gas model,*** constant specific heat,as well as with a variable specific heat gas *** comparison of the results from the two gas models has found that the effect of the variation of specific heat on the velocity of the turbulent boundary layers is relatively small,while its effect on temperature,such as the mean temperature,the temperature fluctuations,is *** is also found that the mean specific heat is quite close to the specific heat calculated by using the mean temperature,indicating that it is possible to do turbulence *** modeling is done under the variable specific heat gas model with the mean temperature as the *** feasibility of such consideration is verified by applying the SST model for variable specific heat turbulence computation.

关键词： hypersonic turbulent boundary layer specific heat direct numerical simulation SST model

The improvement of turbulence modeling for the aerothermal computation of hypersonic turbulent boundary layers

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Science china(Physics,mechanics & Astronomy) 2010年第2期53卷 369-379页

作者： dong ming & zhou heng department of mechanics,tianjin {2.,tianjin 300072.china 1. department of mechanics Tianjin University Tianjin 300072 China

The engineering computation of turbulent flows is mainly based on turbulence modeling,however,accurate aerothermal computation of hypersonic turbulent boundary layers is still a not well-solved problem. Aerothermal computation for turbulent boundary layers on a supersonic or hypersonic blunt cone with small bluntness is done firstly by using both direct numerical simulation and BL model,and seven different cases are investigated. Then the results obtained by the two methods are compared,and the reason causing the differences is found to be the incorrect assumption in the turbulence modeling that the ratio between eddy heat conductivity and eddy viscosity is constant throughout the whole boundary layer. Based on certain theoretical arguments,a method of modifying the expression of eddy heat conductivity in the region surrounding the peak location of the turbulent kinetic energy is proposed,which is verified to be effective,at least for the seven cases investigated.

关键词： hypersonic turbulent boundary layer aerothermal supersonic cone direct numerical simulation(DNS) BL model coefficient of eddy heat conductivity

Statistics and dynamics of coherent structures in compressible wall-bounded turbulence

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Science china(Physics,mechanics & Astronomy) 2024年

作者： ming Yu SiWei dong XianXu Yuan ChunXiao Xu State Key Laboratory of Aerodynamics Key Laboratory of Applied mechanics Institute of Fluid Mechanics Department of Engineering Mechanics Tsinghua University

Compressible wall-bounded turbulence is ubiquitously encountered in modern aerospace and mechanical industries. In this review, we summarize the current state of the literature on the flow physics of compressible wall-bounded turbulence with simple flow geometry and boundary constraints, focusing on the statistics and dynamics of coherent structures, the seemingly organized flow patterns hidden amidst the nonlinear chaotic random processes. We summarize the conclusions brought by recent year studies regarding the influences of the Mach number and wall temperature on the velocity streaks, quasi-streamwise vortices and dilatational motions in the near-wall region, and the large-scale and very-large-scale motions in the outer region, from both statistical and dynamical point of view, with the primary concern of the similarities with and disparities from those in incompressible flows.

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A simulation on bypass transition and its key mechanism

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Science china(Physics,mechanics & Astronomy) 2013年第4期56卷 775-784页

作者： dong ming {2. heng department of mechanics Tianjin University tianjin Key Laboratory of Modern Engineering mechanics

The scenario of bypass transition is generally described theoretically as follows: low-frequency disturbances in the free-stream would generate long stream-wise streaks in the boundary layer, which later would induce secondary instability, leading to rapid increase of high-frequency disturbances, then possibly turbulent spots would emerge, and through their merging, fully developed turbulence appears. This description, however, is insufficient in the sense that it does not provide the explanation on why during the breakdown stage, a large number of waves with different frequencies and wave numbers would appear almost simultaneously, leading to a swift change of the mean flow profile. In this paper, the mechanism leading to this phenomenon is found to be the change of the stability characteristics of mean flow profile, which has a positive feedback effect on the change of the profile itself. And another interesting finding is that, during the transition, the unstable disturbance waves which appear first belong to a branch of inviscid modes, while following the change of the stability characteristics of the mean flow profile, the disturbance waves will change to another branch of inviscid modes, and the latter play the key role in bypass transition.

关键词： bypass transition breakdown instability streak inviscid

VORTEX SHEDDING FREQUENCY DETERMINED BY SURFACE PRESSURE FLUCTUATIONS OF THREE EQUISPACED CYLINDERS

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Journal of Hydrodynamics 1999年第4期11卷 76-85页

作者： dong Li yun, Xu You heng, Huang dong qun department of mechanics and Engineering Science, Fudan university, Shanghai 2.0433, P.R.china

In his paper, the frequency of vortex shedding from three cylinders of the same diameter in equilateral triangular arrangement is determined experimentally by the spectrum analysis of surface pressure fluctuations at a Reynolds number of 3.0×10 4. For α=0°, there exists ‘bistable’ flow at the spacing 2.0. For α=30°, the vortex shedding of the front cylinder is found at small spacing less than 2.0. It is quite different from the case of two cylinders in tandem arrangement only. The side cylinder has great effects on the flow between the other two cylinders in close arrangement. For α=60°, there exists a critical spacing of about 2.5 that the frequency of each cylinders is nearly half of f s below this spacing and equal to f s above it respectively. The interference among three cylinders was negligible in the spacing range above 3.0 at α=0 and 60 deg., and each cylinder behaves as a single cylinder with the same vortex shedding frequency f s. In these small spacing (spacing<3.0), interference occurs seriously and has great effects in a complex fashion on the flow state around three cylinders.

关键词： interference among three cylinders pressure fluctuation vortex shedding frequency. wind tunnel testing

Germline mutation analysis of hPMS2.gene in Chinese families with hereditary nonpolyposis colorectal cancer

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World Journal of Gastroenterology 2010年第30期16卷 3847-3852页

作者： Xia Sheng, Xiao-Yan zhou, Xiang Du, Tai-{2. Zhang, WeiQi Sheng, Da-Ren Shi, department of Pathology, Shanghai Cancer Center, Fudan university, Shanghai 2.0032. china department of Oncology, Shanghai Medical College, Fudan university, Shanghai 2.0032. china heng-Hua zhou, department of Pathology, Shanghai Ninth People’s Hospital Affi liated to Shanghai Jiao Tong university School of Medicine, Shanghai 2.0011, china San-Jun Cai, department of Abdominal Surgery, Cancer Center, Fudan university, Shanghai 2.0032. china department of Pathology Shanghai Cancer Center Fudan University 270 Dong An Road Shanghai 200032 China. shengweiqi2006@***

AIM: To study the germline mutation of hPMS2.gene in 2. unrelated Chinese hereditary nonpolyposis colorectal cancer (HNPCC) probands and to fulfill the screening strategy for HNPCC in Chinese. METHODS: Genomic DNA was extracted from the peripheral blood. To avoid the interference of pseudogene in detection of the remaining 11 exons (exon 1-5, 9, 11-15), long-range polymerase chain reaction (PCR) was conducted to amplify the complete coding region of hPMS2.gene firstly. Then 1/8 of the PCR productswere used as template to amplify the individual exon respectively and DNA sequencing was done. Direct DNA sequencing of the conventional PCR products of exon 6, 7, 8 and 10 of hPMS2.gene was performed. The same analysis was made in 130 healthy persons without family histories of HNPCC to further investigate the pathological effects of the detected missense mutation. RESULTS: One HNPCC proband fulf illed Bethesda guidelines and was found to carry the germline mutation of hPMS2.gene, which has not been reported in Chinese HNPCC families. It was a missense mutation at c.1532.>T of exon 11. It was detected in three controls as well with an occurrence rate of 2.3% (3/130). Since it could not be found in the PMS2.single nucleotide polymorphism (SNP) database, this missense mutation is a new SNP unreported up to date. Meanwhile, 2.0 reported SNPs of hPMS2.gene were detected in the 2. HNPCC probands. The 2.d and 5th exons were probably the hot SNP regions of hPMS2.gene in Chinese HNPCC families involving 53.1% of all reported SNP. CONCLUSION: The germline mutation of hPMS2.gene may be rare in Chinese HNPCC families. The 2.d and 5th exons are hot SNP regions of hPMS2.gene.

关键词： Hereditary nonpolyposis colorectal cancer hPMS2 Missense mutation Single nucleotide polymorphism Colorectal cancer

Atom-referenced and stabilized soliton microcomb

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Science china(Physics,mechanics & Astronomy) 2024年第2期67卷 2-8页

作者： Rui Niu Shuai Wan Tian-Peng Hua Wei-Qiang Wang Zheng-Yu Wang Jin Li Zhu-Bo Wang ming Li Zhen Shen Yu Robert Sun Shui-ming Hu Brent ELittle Sai Tak Chu Wei Zhao Guang-Can Guo Chang-Ling Zou Yun-Feng Xiao Wen-Fu Zhang Chun-Hua dong State Key Laboratory of Transient Optics and Photonics Xi’an Institute of Optics and Precision MechanicsChinese Academy of SciencesXi’an 710119China CAS Key Laboratory of Quantum Information University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of ChinaHefei 230026China university of Chinese Academy of Sciences Beijing 100049China department of Chemical Physics University of Science and Technology of ChinaHefei 230026China department of Physics and Materials Science City University of Hong KongHong Kong 999077China State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics School of PhysicsPeking UniversityBeijing 100871China

For the applications of the frequency comb in microresonators,it is essential to obtain a fully frequency-stabilized microcomb laser *** this study,we present a system for generating a fully atom-referenced stabilized soliton *** pump light around 1560.48 nm is locked to an ultra-low-expansion(ULE)*** pump light is then frequency-doubled and referenced to the atomic transition *** repetition rate of the soliton microcomb is injection-locked to an atomic-clockstabilized radio frequency(RF)source,leading to mHz stabilization at 1 *** a result,all comb lines have been frequencystabilized based on the atomic reference and the ULE cavity,achieving a very high precision of approximately 18 Hz at 1 s,corresponding to the frequency stability of 9.5×10^(-14).Our approach provides a fully stabilized microcomb experiment scheme with no requirement of f-2. technique,which could be easily implemented and generalized to various photonic platforms,thus paving the way towards the ultraprecise optical sources for high precision spectroscopy.

关键词： microcavity frequency comb dissipative Kerr solitons fully stabilized microcomb

NUMERICAL SIMULATION OF HUMAN AIR BREATHING NEAR THE NOSE OUTLET

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Journal of Hydrodynamics 1999年第3期11卷 105-110页

作者： Ma heng Buji People′s Hospital, Shengzhen 518112. P.R.{2. An Yi ran, Zhuang Ning department of mechanics, Peking university, Beijing 100871, P.R.{2. Yan dong Beijing Zhongguancun Hospital, Beijing 100080, P.R.{2. (Received Dec. 30, 1998

Numerical method is used to simulate the air breathing near the outlet of human nose. The process of breathing is visualized. The distribution of the exhausted air density may be useful in designing the medical equipm... 详细信息

关键词： human breathing N S equations air refreshing

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大型薄膜衍射太空望远镜的压电振动主动控制

力学季刊 2024年第2期45卷 309-318页

作者：王展鸿喻恒蔡国平周徐斌杜冬上海交通大学工程力学系水动力学教育部重点实验室上海200240 上海卫星工程研究所上海201109

随着航天技术的发展,大型薄膜衍射太空望远镜以其质量体积小、成像分辨率高、易折展等优点获得广泛的关注与研究.本文对大型薄膜衍射太空望远镜结构进行振动控制研究,给出基于压电作动器的振动控制方案.首先采用有限元方法建立结构的动... 详细信息

随着航天技术的发展,大型薄膜衍射太空望远镜以其质量体积小、成像分辨率高、易折展等优点获得广泛的关注与研究.本文对大型薄膜衍射太空望远镜结构进行振动控制研究,给出基于压电作动器的振动控制方案.首先采用有限元方法建立结构的动力学模型,然后根据可控性准则进行作动器位置寻找,之后基于模糊Proportional-Derivative (PD)算法设计控制律,最后通过数值仿真验证本文研究方法的有效性.本文中,还通过数值仿真研究了压电作动器数量与控制稳定所需时间的对应关系,另外还进行了控制律鲁棒性的研究.

关键词：太空望远镜压电作动器模糊比例-微分鲁棒性

紫花苜蓿、白三叶硒蛋白的提取方法筛选及工艺优化

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草地学报 2024年第2期32卷 654-660页

作者：吴倩倩苏娅曾祥明李栋恒程巍郝俊贵州大学动物科学学院草业科学系贵州贵阳550025

硒蛋白是微量元素硒(Se)在生物体内发挥生物学作用的主要形式,对宿主在抗氧化、抗炎、提高免疫力等方面有重要意义。为探究不同豆科牧草硒蛋白提取方法筛选及其工艺优化,本研究以紫花苜蓿(Medicago sativa)和白三叶(Trifolium repens)... 详细信息

硒蛋白是微量元素硒(Se)在生物体内发挥生物学作用的主要形式,对宿主在抗氧化、抗炎、提高免疫力等方面有重要意义。为探究不同豆科牧草硒蛋白提取方法筛选及其工艺优化,本研究以紫花苜蓿(Medicago sativa)和白三叶(Trifolium repens)为原材料,采用碱提法(NaOH)、盐提法(NaCl)、酸提法(HCl)和水提法(H2.)4种溶剂提取法获得牧草硒蛋白,并在单因素试验基础上进行正交试验优化硒蛋白提取工艺。结果表明:碱提法提取紫花苜蓿和白三叶硒蛋白效果最好。紫花苜蓿最佳工艺条件为温度40℃、料液比1∶2. g·mL^(-1)、碱浓度0.15 mol·L^(-1),硒蛋白提取率为35.39%。白三叶最佳工艺条件为温度50℃、料液比1∶40 g·mL^(-1)、碱浓度0.15 mol·L^(-1),硒蛋白提取率为35.52.。本研究可为从豆科牧草中提取硒蛋白提供重要的技术支持和实践指导。

关键词：紫花苜蓿白三叶硒蛋白提取工艺优化

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