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WAVE-CURRENT FORCES ON BIPILES IN TANDEM ARRAY

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Journal of Hydrodynamics 1991年第4期3卷 66-75页

作者： yu-cheng, li Feng-long, Wang Dalian Univ of Technology Dalian China

The in-line and lift forces on bipiles in tandem array induced by both irregular waves and currents were investigated experimentally in this paper. The characteristics in both time and frequency domain of inline, lift and resultant forces as well were analyzed. The grouping effect coefficients of in-line and resultant forces on two piles related to KC number and relative spacing parameters are given. A comparison of the magnitude and direction of resultant forces on bipiles in tandem array with the corresponding values for single cylinder is also made.

关键词： Hydrodynamics Fluid Structure Interaction Mathematical Techniques Frequency Domain Analysis Mathematical Techniques Time Domain Analysis Mechanical Variables Measurement Forces Water Waves Analysis

Recent developments in high-performance Nafion membranes for hydrogen fuel cells applications

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Petroleum Science 2022年第3期19卷 1371-1381页

作者： li-yu Zhu yu-cheng li Jing liu Jing He Lu-Ying Wang Jian-Du Lei Beijing Key Laboratory of lignocellulosic Chemistry College of Material Science and TechnologyBeijing Forestry University

As a promising alternative to petroleum fossil energy,polymer electrolyte membrane fuel cell has drawn considerable attention due to its low pollution emission,high energy density,portability,and long operation *** exchange membrane(PEM)like Nafion plays an essential role as the core of fuel cell.A good PEM must have satisfactory performance such as high proton conductivity,excellent mechanical strength,electrochemical stability,and suitable for making membrane electrode assemblies(MEA).However,performance degradation and high permeability remain the main shortcomings of ***,the development of a new PEM with better performance in some special conditions is greatly *** this review,we aim to summarize the latest achievements in improving the Nafion performance that works well under elevated temperature or methanol-fueled *** methods described in this article can be divided into some categories,utilizing hydrophilic inorganic material,metal-organic frameworks,nanocomposites,and ionic *** addition,the mechanism of proton conduction in Nafion membranes is *** composite membranes exhibit some desirable characteristics,but the development is still at an early *** the future,revolutionary approaches are needed to accelerate the application of fuel cells and promote the renewal of energy structure.

关键词： Fossil energy Fuel cell Proton exchange membrane Proton conductivity Inorganic fillers

The commutant and similarity invariant of analytic Toeplitz operators on Bergman space

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Science China Mathematics 2007年第5期50卷 651-664页

作者： Chun-Ian JIANG yu-cheng li Department of Mathematics Hebei Normal UniversityShijiazhuang 050016China

The famous von Neumann-Wold Theorem tells us that each analytic Toeplitz operator with n + 1-Blaschke factors is unitary to n + 1 copies of the unilateral shift on the Hardy space. It is obvious that the von Neumann-Wold Theorem does not hold in the Bergman space. In this paper, using the basis constructed by Michael and Zhu on the Bergman space we prove that each analytic Toeplitz operator M B(z) is similar to n + 1 copies of the Bergman shift if and only if B(z) is an n + 1-Blaschke product. From the above theorem, we characterize the similarity invariant of some analytic Toeplitz operators by using K 0-group term.

关键词： Bergman space analytic Toeplitz operators invariant subspace commutant similarity invariant K 0-group 32A36 46J40 47A15

Growth of Aligned Carbon Nanotubes on Large Scale by Methane Decomposition with Deactivation Inhibitor

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Journal of Natural Gas Chemistry 2007年第4期16卷 382-388页

作者： Hao yu Zhili li cheng Zhang Feng Peng Hongjuan Wang School of Chemical and Energy Engineering South China University of Technology Guangzhou 510650 Guangdong China

The effects of additives containing iron or nickel during chemical vapor deposition （CVD） on the growth of carbon nanotubes （CNTs） by methane decomposition on Mo/MgO catalyst were investigated. Ferrocene and nickel nitrate were introduced as deactivation inhibitors by in-situ evaporation during CVD. The precisely controlled in-situ introduction of these inhibitors increased the surface renewal of catalyst, and therefore prevented the catalyst from deactivation. Using this method, aligned multi-walled CNTs with parallel mesopores can be produced on a large scale.

关键词： aligned carbon nanotubes chemical vapor deposition deactivation inhibitor methane decomposition Mo/MgO catalyst ferrocene nickel nitrate

Hydrodynamic coefficients of a simplified floating system of gravity cage in waves

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第5期9卷 654-663页

作者： Chang-wen WU Fu-kun GUI yu-cheng li Wei-huan FANG Marine Science School Zhejiang Ocean University Zhoushan 316000 China State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China College of Animal Sciences Zhejiang University Hangzhou 310058 China

Numerical simulation and experimental tests were carried out to examine the hydrodynamic behaviors of a double-column floating system of gravity cage under wave conditions. A floating system of gravity cage can be treated as a small-sized floating structure when compared with the wavelengths. The main problem in calculating the wave loads on the small-sized floating structure is to obtain the reasonable force coefficients, which may differ from a submerged structure. In this paper, the floating system of gravity cage is simplified to a 2D problem, where the floating system is set symmetrically under wave conditions. The motion equations were deduced under wave conditions and a specific method was proposed to resolve the problem of wave forces acting on a small-sized floating system of gravity cage at water surface. Results of the numerical method were compared with those from model tests and the hydrodynamic coefficients Cn and Cr were studied. It is found that Cn ranges from 0.6 to 1.0 while Cr is between 0.4 and 0.6 in this study. The results are useful for research on the hydrodynamic behavior of the deep-water gravity sea cages.

关键词： Gravity cage Floating system Hydrodynamic coefficients Waves

The Effect of Vineyard Cover Crop on Main Monomeric Phenols of Grape Berry and Wine in Vitis viniferal L. cv. Cabernet Sauvignon

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Agricultural Sciences in China 2010年第3期9卷 440-448页

作者： XI Zhu-mei ZHANG Zhen-wen cheng yu-feng li Hua College of Enology Northwest A＆F University/Shaanxi Engineering Research Center for Viti-Viniculture Yangling 712100 P.R.China

This study was conducted to determine the effect of cover crop inter-row in vineyard on main mono-phenol content of grape berry and wine. Three such cover crops, two perennial legumes （white clover and alfalfa） and a perennial gramineous grass （tall fescue） were sown in vineyard. The main phenolic compounds of mature grape berry and wines vinified under the same conditions were extracted with ethyl acetate and diethyl ether and analyzed by high- performance liquid chromatography （HPLC） by comparing to soil tillage. A total of ten phenolic compounds were identified and quantified in the different grape berry and wines, including nonflavonoids （hydroxybenzoic and hydroxycinnamic acids） and flavonoids （flavanols and flavonols）. The concentration of flavonoid compounds （409.43 to 538.63 mg kg^-1 and 56.16 to 81.30 mg L^-1） was higher than nonflavonoids （76.91 to 98.85 mg kg^-1 and 30.65 to 41.22 mg L^-1） for Cabernet Sauvignon grape and wine under different treatments, respectively. In the flavonoid phenolics, Catechin was the most abundant in the different grapes and wines, accounting for 74.94 to 79.70% and 48.60 to 50.62% of total nonanthocyanin phenolics quantified, respectively. Compared to soil tillage, the sward treatments showed a higher content of main mono-phenol and total nonanthocyanin phenolics in grapes and wines. There were significant differences between two cover crop treatments （tall fescue and white clover） and soil tillage for the content of benzoic acid, salicylic acid, caffeic acid, catechin, and total phenolics in the grape berry （P 〈 0.05 or P〈0.01）. The wine from tall fescue cover crop had the highest gallic acid, caffeic acid and catechin. Cover crop system increased the total nonanthocyanin phenolics of grapes and wines in order of the four treatments： tall fescue, white clover, alfalfa, and soil tillage （control）. Cover crop in vineyard increased total phenols of grape berry and wine, and thus improved the quality of wine evidently.

关键词： vineyard cover crops inter-row Cabernet Sauvignon grape berry wine monomeric phenols

Multi-objective robust airfoil optimization based on non-uniform rational B-spline (NURBS) representation

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Science China(Technological Sciences) 2010年第10期53卷 2708-2717页

作者： liANG yu, cheng XiaoQuan, li ZhengNeng & XIANG JinWu School of Aeronautic Science and Engineering, Beihang University, Beijing 100191, China School of Aeronautic Science and Engineering Beihang University Beijing China

In order to improve airfoil performance under different flight conditions and to make the performance insensitive to off-design condition at the same time,a multi-objective optimization approach considering robust design has been developed and applied to airfoil design. Non-uniform rational B-spline (NURBS) representation is adopted in airfoil design process,control points and related weights around airfoil are used as design variables. Two airfoil representation cases show that the NURBS method can get airfoil geometry with max geometry error less than 0.0019. By using six-sigma robust approach in multi-objective airfoil design,each sub-objective function of the problem has robustness property. By adopting multi-objective genetic algorithm that is based on non-dominated sorting,a set of non-dominated airfoil solutions with robustness can be obtained in the design. The optimum robust airfoil can be traded off and selected in these non-dominated solutions by design tendency. By using the above methods,a multi-objective robust optimization was conducted for NASA SC0712 airfoil. After performing robust airfoil optimization,the mean value of drag coefficient at Ma0.7-0.8 and the mean value of lift coefficient at post stall regime (Ma0.3) have been improved by 12.2% and 25.4%. By comparing the aerodynamic force coefficients of optimization result,it shows that: different from single robust airfoil design which just improves the property of drag divergence at Ma0.7-0.8,multi-objective robust design can improve both the drag divergence property at Ma0.7-0.8 and stall property at low speed. The design cases show that the multi-objective robust design method makes the airfoil performance robust under different off-design conditions.

关键词： robust design multi-objective optimization NURBS Pareto front airfoil

Comparison of different methods of intestinal obstruction in a rat model

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World Journal of Gastroenterology 2013年第5期19卷 692-705页

作者： Meng-Lang yuan Zheng Yang yu-cheng li Lan-Lan Shi Jia-ling Guo yu-Qin Huang Xia Kang Jing-Jing cheng Yang Chen Ting yu De-Qi Cao Huan Pang Xiao Zhang Department of Clinical Medicine Chengdu Medical College Department of Experimental Technology Chengdu Medical College Department of Pharmaceutics Chengdu Medical College Department of Laboratory Medicine Chengdu Medical College

AIM:To investigate different methods of creating incomplete intestinal obstruction in a rat model and to compare their electrophysiologic,morphologic and histologic characteristics. METHODS:Rat ileum was partially obstructed by the respective application of:braided silk(penetrated the mesentery and surrounded intestine);half ligation (penetrated directly and ligated 1/2 cross-section of the intestine);wide pipe(6 mm in width,surrounded the intestine);narrow pipe(2 mm in width,surrounded the intestine).A control was also included(no obstruction). Various behavioral and electrophysiologic variables, as well as morphologic and immunohistochemical observations were recorded by blinded investigators at different time points(12,24,48,72 h),including daily general condition,ileal wet weight and circumference, macromorphous and micromorphous intestine,bowel movement capability in vivo and in vitro,slow wave and neural electrical activity,and the number of c-Kit positive interstitial cells of Cajal(ICC). RESULTS:Despite being of a similar general condition, these methods resulted in different levels of obstruction in each group compared with the control at different time points(12,24,48,72 h).However,these fields of the wide pipe rat showed significantly differences when compared with the other three obstructed groups at 12 to 72 h,including macroscopic and histological presentation,intestinal transit ratio and contractility,circumference and wet weight,amplitude and frequency of nerve electrical discharge and slow wave,and ICC numbers(all Pliable and stable than the other methods of obstruction,demonstrating that use of the wide pipe method can be a useful model of incomplete intestinal obstruction.

关键词： Intestinal obstruction Model Comparative study Electrophysiology Morphology Interstitial cells of Cajal

Intercross population study reveals that co-mutation of mitfa genes in two subgenomes induces red skin color in common carp(Cyprinus carpio wuyuanensis)

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Zoological Research 2023年第2期44卷 276-286页

作者： Bi-Jun li lin Chen Meng-Zhen Yan Xiao-Qing Zou yu-lin Bai Ya-Guo Xue Zhou Jiang Bao-Hua Chen cheng-yu li Qian He Jian-Xin Feng Tao Zhou Peng Xu State Key Laboratory of Marine Environmental Science College of Ocean and Earth SciencesXiamen UniversityXiamenFujian 361102China Fujian Key Laboratory of Genetics and Breeding of Marine Organisms College of Ocean and Earth SciencesXiamen UniversityXiamenFujian 361102China College of Fisheries Henan Normal UniversityXinxiangHenan 453007China Henan Academy of Fishery Science ZhengzhouHenan 450039China

Common carp are among the oldest domesticated fish in the *** such,there are many food and ornamental carp strains with abundant phenotypic variations due to natural and artificial *** red carp(HB,Cyprinus carpio wuyuanensis),an indigenous strain in China,is renowned for its unique body morphology and reddish *** reveal the genetic basis underlying the distinct skin color of HB,we constructed an improved highfidelity(HiFi) HB genome with good contiguity,completeness,and *** structure comparison was conducted between HB and a representative wild strain,Yellow River carp(YR,*** haematopterus),to identify structural variants and genes under positive *** of artificial selection during domestication were identified in HB and YR populations,while phenotype mapping was performed in a segregating population generated by HB×YR *** color in HB was associated with regions with fixed *** simultaneous mutation and superposition of a pair of homologous genes(mitfa) in chromosomes A06 and B06 conferred the reddish color in domesticated *** analysis of common carp with different alleles of the mitfa mutation confirmed that gene duplication can buffer the deleterious effects of mutation in *** study provides new insights into genotype-phenotype associations in allotetraploid species and lays a foundation for future breeding of common carp.

关键词： Cyprinus carpio Artificial selection Coloration mitfa Structural variant