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Experimental Study of Hydrodynamic and Self-Buried Behavior of Submarine Pipeline with Perpendicular Spoilers

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China Ocean Engineering 2021年第2期35卷 250-261页

作者： FAN Hong-xia WANG Jian-zhong ZHU Li-jun WANG Nai-ru CHEN huai State Key Laboratory of Hydrology Water Resources and Hydraulic EngineeringNanjing Hydraulic Research InstituteNanjing 210029China

The spoiler is a kind of device to disturb current and promote *** present,all submarine pipeline spoilers at home and abroad are parallel spoilers,that is,the plane of the spoiler is parallel to the vertical plane of the pipeline *** to the results of indoor experiments,when the pipeline with the forward spoiler is installed perpendicular to the direction of water flow,the spoiler will accelerate the seabed erosion and cause the pipeline to endure downward pressure,which will eventually cause the pipeline self-buried to form a ***,when the pipeline direction is consistent with the flow direction,the self-buried behavior and protective effect is *** aiming at the defect that the forward spoiler cannot be self-buried when the direction of the pipeline and the flow are basically parallel,the spoiler burying aid device perpendicular to the pipeline axis has been innovatively developed,and the hydrodynamic changes and sediment erosion characteristics near the pipeline after the installation of the device were studied based on the *** reveal that although the perpendicular spoiler cannot generate downforce,it can greatly increase the turbulent kinetic energy of the flow and the rate of sediment *** larger the angle between the pipeline axis and the spoiler plane is,the larger the increase in turbulent energy will *** increase in turbulent energy near the bed surface can reach up about 70%when the angle is 90°,while serious sediment erosion mainly occurs along both sides of the pipeline with a distance of about 2−4 times the pipe *** the future,we can further explore the influence of the perpendicular spoiler size and installation position on the pipeline downforce and the effect of burying *** the same time,field tests on the perpendicular spoiler burying aid device currently developed will conduct to observe the actual effect of perpendicular spoiler promoting pipeline scouring and buryi

关键词： submarine pipeline spoiler self-burial turbulent kinetic energy sediment erosion

Nanoparticle nucleation and coagulation in a mixing layer

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Acta Mechanica Sinica 2010年第4期26卷 521-529页

作者： Jian-zhong Lin yan-Hua Liu China Jiliang University 310018 Hangzhou China Department of Mechanics Zhejiang University310027 Hangzhou China

Numerical simulation of nanoparticle nucleation and coagulation in a mixing layer with sulfuric acid vapor binary system is performed using the large eddy simulation and the direct quadrature method of moment. The distributions of number concentration, volume concentration, and average diameter of nanoparticles are obtained. The results show that the coherent structures have an important effect on the distributions of number concentration, volume concentration and average diameter of nanoparticles via continuously transporting and diffusing the nanoparticles to the area of low particle concentration. In the streamwise direction, the number concentration of nanoparticles decreases, while the volume concentration and the average diameter increase. The distributions of number concentration, volume concentration and average diameter of nanoparticles are spatially inhomogeneous. The characteristic time of nucleation is shorter than that of coagulation. The nucleation takes place more easily in the area of low temperature because where the number concentration of nanoparticles is high, while the intensity of coagulation is mainly affected by the number concentration. Both nucleation and coagulation result in the variation of average diameter of nanoparticles.

关键词： Nanoparticles Nucleation - Coagulation Mixing layer Direct quadrature method of moment

Investigation of the sediment transport capacity in vegetated open channel flow

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Journal of Hydrodynamics 2021年第2期33卷 386-389页

作者： Wen-xin huai Xiang Wang Yakun Guo Zhao-hua Sun zhong-hua yang State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China Faculty of Engineering and Informatics University of BradfordBradfordUK

The suspended sediment transport capacity is important for estimating the suspended load concentration and the ecological environment of the *** far,few studies have been conducted to investigate the suspended sediment transport capacity in the vegetated sediment-laden *** this study,a new formula is derived to predict the sediment transport capacity in a vegetated flow by considering the absolute value of the energy loss between the sediment-laden flow and the clear water ***,the formula is expressed in a practical form by using the logarithmic matching method.

关键词： Sediment transport vegetation suspended sediment concentration

Study on excitation of the two-tone acoustic characteristic of the chime bell of Marquis Yi of Zeng by finite element method

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Chinese Science Bulletin 2007年第16期52卷 2167-2173页

作者： ZHANG huai yan ZhenZhen yanG ChangChun SHI YaoLinit Graduate University of Chinese Academy of Sciences Beiiinq 100049 China Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

The bronze chime bells of Marquis Yi of Zeng are precious cultural relics of China. The bells have a two-tone acoustic characteristic,i.e.,striking different parts of the bell generates different tones. In this study,we use a finite element method to simulate the propagation of elastic waves and the generation of free oscillations of the bell. Vibrations with different spectral characteristics can be obtained by striking different parts of the chime bell of Marquis Yi of Zeng. By the observation of the vibration de-sign and through spectral analysis,we further help the understanding of the two-tone acoustic char-acteristic of the chime bell of Marquis Yi of Zeng.

关键词：曾侯乙乐器钟声有限元法双声学特性

Effect of Solution Treatment on Microstructure and Corrosion Properties of Mg–4Gd–1Y–1Zn–0.5Ca–1Zr Alloy

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Acta Metallurgica Sinica(English Letters) 2018年第8期31卷 865-872页

作者： Jian-Wei Dai Xiao-Bo Zhang yang Fei Zhang-zhong Wang huai-Ming Sui School of Materials Science and Engineering Nanjing Institute of TechnologyNanjing 211167China Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology Nanjing 211167China yangzhou Fengming Optronic New Material Co. LtdYangzhou 225117China

The as-cast multi-element Mg–4Gd–1Y–1Zn–0.5Ca–1Zr alloy with low rare earth additions was prepared, and the solution treatment was applied at different temperatures. The microstructural evolution of the alloy was characterized by optical microscopy and scanning electron microscopy, and corrosion properties of the alloy in 3.5% NaCl solution were evaluated by immersion and electrochemical tests. The results indicate that the as-cast alloy is composed of the a-Mg matrix,lamellar long-period stacking-ordered（LPSO） structure and eutectic phase. The LPSO structure exists with more volume fraction in the alloy solution-treated at 440 °C, but disappears with the increase in the solution temperature. For all the solution-treated alloys, the precipitated phases are detected. The corrosion rates of the alloys decrease first and then increase slightly with the increase in the solution temperature, and the corrosion resistance of the solution-treated alloys is more than four times as good as that of the as-cast alloy. In addition, the alloy solution-treated at 480 °C for 6 h shows the best corrosion property.

关键词： Magnesium alloy Solution treatment Microstructure Corrosion properties

Oscillating Frequency Response of a Langasite Crystal Microbalance in Liquid Phase

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Chinese Chemical Letters 2005年第11期16卷 1547-1550页

作者： Qi KANG huai Jin ZHANG Xue Yong LIU Da zhong SHEN School of Chemistry and Chemical Engineering Shandong University Jinan 250100 State Key Laboratory of Crystal Materials Shandong University Jinan 250100

The frequency responses of a langasite crystal microbalance （LCM） in liquid phase were investigated. It was shown that the LCM possessed much stronger oscillating ability in liquid phase than that of the commonly used quartz crystal microbalance （QCM）. The frequency shifts of the LCM to the changes in mass loading, as well as viscosity and density of the liquid were measured. The LCM was applied to monitor the adsorption process of an ionic liquid film to ethanol vapor.

关键词： Piezoelectric sensor langasite crystal frequency response ionic liquid.

Flow dynamics and sediment transport in vegetated rivers:A review

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Journal of Hydrodynamics 2021年第3期33卷 400-420页

作者： Wen-xin huai Shuolin Li Gabriel G.Katul Meng-yang Liu zhong-hua yang State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China Department of Civil and Environmental Engineering Duke UniversityDurhamNCUSA Nicholas School of the Environment and Earth Science Duke UniversityDurhamNCUSA

The significance of riparian vegetation on river flow and material transport is not in *** laws,sediment erosion and deposition,and element cycling must all be adjusted from their canonical rough-wall boundary layer to accommodate the presence of aquatic *** turn,the growth and colonization of riparian vegetation are affected by fluvial processes and river morphology on longer time *** interactions and feedbacks at multiple time scales are now drawing significant attention within the research community given their relevance to river *** this reason,a review summarizing methods,general laws,qualitative cognition,and quantitative models regarding the interplay between aquatic plants,flow dynamics,and sediment transport in vegetated rivers is in ***,pitfalls,knowledge gaps,and daunting challenges to the current state of knowledge are also *** a multidisciplinary research topic,a future research agenda and opportunities pertinent to river management and enhancement of ecosystem services are also highlighted.

关键词： Canopy flow river morphology riparian vegetation sediment transport

Discussion on origin of Pn velocity variation in China and adjacent region

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Acta Seismologica Sinica(English Edition) 2004年第1期17卷 1-11页

作者： PEI Shun-ping(裴顺平) XU zhong-huai(许忠淮) WANG Su-yun(汪素云) Computational Geodynamics Laboratory Department of Geophysics Peking University Beijing 100871 China Institute of Geophysics China Seismological Bureau Beijing 100081 China Institute of Geophysics China Seismological Bureau Beijing 100081 China

Pn velocity lateral variation and anisotropy images were reconstructed by adding about 50 000 travel times from the regional seismic networks to the datum set of near 40 000 travel times from National Seismic Network of China used by WANG, et al. We discussed the relation of Pn velocity variation to Moho depth, Earths heat flow, distribution of Cenozoic volcanic rock and the result of rock experiment under high pressure and high temperature. The result of quantitative analysis indicates that Pn velocity is positively correlated with the crust thickness and negatively correlated with the Earths heat flow. Two linear regression equations, one between Pn velocity and crust thickness, and the other between Pn velocity and heat flow, were obtained. The rate of variation of Pn veloc-ity vP with pressure P, Pv/p, estimated from the velocity variation with crust thickness Hv/p, is close to the result obtained from the rock experiment under high pressure and high temperature. If the effect of crust thick-ness on Pn velocity is deducted from the velocity variation, then the low Pn velocity beneath Qinghai-Xizang pla-teau is more notable. The low Pn velocity regions well agree with the Cenozoic volcanic rock. In the several re-gions with significant anisotropy, the direction of fast Pn velocity is consistent with the orientation of maximum principal crustal compressive stress, and also with the direction of present-day crustal movement. It indicates that the fast Pn velocity direction may be related to the deformation or flow of top mantle material along the direction of maximum pressure.

关键词： Pn tomography anisotropy China and adjacent region

Wick Calculus for Nonlinear Gaussian Functionals

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Acta Mathematicae Applicatae Sinica 2009年第3期25卷 399-414页

作者： Yao-zhong Hu Jia-an yan Department of Mathematics University of Kansas 405 Snow Hall Lawrence Kansas 66045-2142 USA 2Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

This paper surveys some results on Wick product and Wick renormalization. The framework is the abstract Wiener space. Some known results on Wick product and Wick renormalization in the white noise analysis framework are presented for classical random variables. Some conditions are described for random variables whose Wick product or whose renormalization are integrable random variables. Relevant results on multiple Wiener integrals, second quantization operator, Malliavin calculus and their relations with the Wick product and Wick renormalization are also briefly presented. A useful tool for Wick product is the S-transform which is also described without the introduction of generalized random variables.

关键词： Malliavin calculus multiple integral chaos decomposition Wick product Wick renormalization