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Investigation on the vortical structures by the Liutex method in turbulent channels at Re_(τ)=180 with scalloped and triangular riblet control

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Journal of Hydrodynamics 2024年第1期36卷 35-52页

作者： Zhang-dan yu Shang Jiang Hai-dong yu Bi-yu Pang Xin Dong Yi-qian Wang School of Mathematical Sciences Soochow UniversitySuzhou215006China Beijing Institute of Astronautical System Engineering Beijing100076China

Riblets are a series of small protrusions formed along the flow direction,which have been extensively studied as a passive turbulent drag reduction *** and numerical simulations have shown that well-designed riblets can significantly reduce drag in turbulent flows,making them highly promising and valuable for various *** this study,we focus on a scalloped riblet,which is designed by smoothly connecting two third-order polynomials,and thus the sharpness of the tip and the curvature of the valley can be well *** conduct direct numerical simulations of turbulent channel with smooth plate,scalloped riblet-mounted and triangular riblet-mounted *** in wall units of W^(+)=20 and height-width ratio ofγ=0.5 are selected for both riblet *** with the smooth plate case,the scalloped riblet case achieves an 8.68%drag reduction,while the triangular riblet case achieves a 4.79%drag *** obtained drag reduction rate of the triangular riblet is consistent with previous experiments and simulations,and the results indicate that the scalloped riblet is more effective in reducing drag and deserves further *** compare turbulent statistics of the scalloped riblet case with those of the triangular riblet *** mean velocity profiles of riblets are similar,but both the Reynolds shear stress and second-order statistics of velocity fluctuations and Liutex are significantly reduced in the scalloped riblets controlled turbulent channel,indicating that the scalloped riblet can more effectively suppress the spanwise and wall-normal turbulent intensity near the *** also compare the pre-multiplied spectra of streamwise velocity and streamwise Liutex component for the three cases to investigate the energy distribution and characteristics of Liutex *** Liutex vortex identification method is also utilized to analyze the instantaneous flow field,which provides insights into the flow field and could be bene

关键词： Liutex vector riblet drag reduction tip sharpness turbulent channel scalloped

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A Weighted Flow related to a Trudinger–Moser Functional on Closed Riemann Surface

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Acta Mathematica Sinica,English Series 2024年第9期40卷 2244-2262页

作者： Peng Xiu yu School of Mathematics Renmin University of ChinaBeijing 100872P.R.China

In this paper,with(Σ,g)being a closed Riemann surface,we analyze the possible concentration behavior of a heat flow related to the Trudinger–Moser *** obtain a long time existence for the *** along some sequence of times t_(k)→+∞,we can deduce the convergence of the flow in H2(Σ).Furthermore,the limit function is a critical point of the Trudinger–Moser functional under certain constraint.

关键词： Trudinger-Moser inequality global convergence heat flow

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硫酸钠对蛋鸡生产性能、抗氧化能力、肠道形态及盲肠微生物菌群的影响

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动物营养学报 2015年第11期27卷 3358-3365页

作者：熊平文刘兵陈娜娜何俊娜余东游浙江大学动物科学学院农业部华东动物营养与饲料重点实验室杭州310058

本试验旨在研究饲粮中添加硫酸钠对蛋鸡生产性能、抗氧化能力、肠道形态及盲肠微生物菌群的影响。选取健康且体重和产蛋率相近的20周龄海兰白蛋鸡450只,随机分为5组,每组6个重复,每个重复15只鸡。对照组饲喂基础饲粮,试验组分别饲喂在... 详细信息

本试验旨在研究饲粮中添加硫酸钠对蛋鸡生产性能、抗氧化能力、肠道形态及盲肠微生物菌群的影响。选取健康且体重和产蛋率相近的20周龄海兰白蛋鸡450只,随机分为5组,每组6个重复,每个重复15只鸡。对照组饲喂基础饲粮,试验组分别饲喂在基础饲粮中添加0.3%、0.6%、1.5%、3.0%硫酸钠的试验饲粮。试验期8周。结果显示：1）饲粮中添加硫酸钠可促进蛋鸡产蛋,其中以低剂量（0.3%和0.6%）组效果较佳,但差异不显著（P〉0.05）。2）与对照组相比,饲粮中添加硫酸钠对血浆和肝脏的抗氧化指标均无显著影响（P〉0.05）。与0.6%组相比,高剂量（1.5%和3.0%）组血浆的谷胱甘肽过氧化物酶（GSH-Px）活性和肝脏的总超氧化物歧化酶（T-SOD）活性显著或极显著降低（P〈0.05或P〈0.01）,3.0%组的血浆总抗氧化能力（T-AOC）和肝脏GSH-Px活性显著降低（P〈0.05）。3）与对照组相比,0.6%组十二指肠和回肠的绒毛高度分别提高了30.51%和42.63%（P〈0.01）,0.6%组十二指肠的隐窝深度显著降低（P〈0.05）,绒隐比显著提高（P〈0.05）。与0.6%组相比,高剂量（1.5%和3.0%）组十二指肠和回肠的绒毛高度及十二指肠的绒隐比极显著降低（P〈0.01）,3.0%组十二指肠和回肠的隐窝深度极显著增加（P〈0.01）。4）与对照组相比,低剂量（0.3%和0.6%）组极显著降低了大肠杆菌数量（P〈0.01）,且以0.6%组效果最佳。与0.6%组相比,高剂量（1.5%和3.0%）组肠杆菌和大肠杆菌数量显著或极显著增加（P〈0.05或P〈0.01）。本试验结果提示,饲粮中添加0.3%-0.6%的硫酸钠能提高蛋鸡的抗氧化能力,改善肠道形态和调节微生物菌群,且蛋鸡饲粮中硫酸钠适宜添加水平为0.6%。

关键词：硫酸钠蛋鸡生产性能抗氧化能力肠道形态微生物菌群

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The Enhanced Period Map and Equivariant Deformation Quantizations of Nilpotent Orbits

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Acta Mathematica Sinica,English Series 2024年第3期40卷 885-934页

作者： Shi Lin yu Department of Mathematics School of Mathematical SciencesXiamen UniversityXiamen 361005P.R.China

In a previous paper,the author and his collaborator studied the problem of lifting Hamil-tonian group actions on symplectic varieties and Lagrangian subvarieties to their graded deformation quantizations and apply the general results to coadjoint orbit method for semisimple Lie *** even quantizations were considered *** this paper,these results are generalized to the case of general quantizations with arbitrary *** key step is to introduce an enhanced version of the(truncated)period map defined by Bezrukavnikov and Kaledin for quantizations of any smooth sym-plectic variety X,with values in the space of Picard Lie algebroid over *** an application,we study quantizations of nilpotent orbits of real semisimple groups satisfying certain codimension condition.

关键词： Coadjoint orbit method deformation quantization Harish-Chandra modules semisimple Liegroups

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Multi-physical fields distribution in billet during helical electromagnetic stirring:A numerical simulation research

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China Foundry 2024年第1期21卷 51-59页

作者： Dong Pan Qing-tao Guo Kai-lun Zhang Fu-zhi yu yu-ying Li yu-bao Xiao State Key Laboratory of Metal Materials for Marine Equipment and Application Anshan 114009LiaoningChina Ansteel Beijing Research Institute Co. Ltd.Beijing 102200China

Electromagnetic stirring is one of the widely applied techniques to modify the quality of casting *** from conventional rotate stirring,the helical stirring is more professional in assisting multi-dimensional flow of molten metal and eliminating solidification *** this study,the single-winding helical stirring(SWHS)was introduced,offering advantages such as smaller volume and lower electromagnetic shielding compared to traditional helical stirring *** a comprehensive numerical simulation,the stirring parameters of SWHS were adjusted to yoke inclination angle of 43°and frequency of 12 *** higher electromagnetic force and flow velocity in drawing direction,as well as the lower temperature gradient induced by the SWHS,are positive factors for homogeneous solidification of *** experimental results on Al-8%Si alloy and 0.4%C-1.1%Mn steel demonstrate that compared to rotate stirring,the SWHS process can induce better billet quality and is more effective in accelerating the equiaxed expansion and reducing element *** SWHS process can enhance the equiaxed ratio of the billet by 58.3%and reduce segregation degree of carbon element by 10.97%.Consequently,SWHS holds great promise as a potential approach for improving the quality of continuous casting billets.

关键词： billet electromagnetic stirring helical solidification element segregation numerical simulation

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Numerical investigations of the interactions between bubble induced shock waves and particle based on OpenFOAM

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Journal of Hydrodynamics 2024年第2期36卷 355-362页

作者： Jia-xin yu Jin-sen Hu yu-hang Liu Yi-fan Liu Dan Gao yu-ning Zhang Key Laboratory of Power Station Energy Transfer Conversion and System Ministry of EducationSchool of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China

The presence of particles and the shock waves generated by the cavitation bubbles can significantly affect the safety and the performance of hydrodynamic *** the present paper,the shock waves generated by cavitation bubble collapsing near the particle are numerically investigated based on the OpenFOAM together with the numerical schlieren for the shock wave *** numerical results reveal that the stand-off distance is one of the paramount factors affecting the interactions between the particle and the shock *** different kinds of shock waves(e.g.,bubble-inception,jet formation,particle reflected and jet-split shock waves)are observed during the bubble collapsing near the *** stand-off distance smaller than 0.5 or larger than 1.1,the maximum pressure at particle surface generated by the bubble growth can surpass those of the collapse stage.

关键词： Particle-bubble interaction shockwaves jetdynamics

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饲粮色氨酸水平对蛋鸡生产性能及蛋品质的影响

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动物营养学报 2010年第5期22卷 1265-1270页

作者：余东游周斌饶巍董信阳邹晓庭浙江大学饲料科学研究所动物分子营养学教育部重点实验室杭州310029

为探讨饲粮色氨酸水平对蛋鸡生产性能和蛋品质的影响,本试验将720羽300日龄罗曼蛋鸡随机分成5组,每组3个重复,每个重复48羽。对照组饲粮为色氨酸含量为0.16%的玉米-豆粕型基础饲粮,4个试验组饲粮为通过在基础饲粮中添加色氨酸使色氨酸... 详细信息

为探讨饲粮色氨酸水平对蛋鸡生产性能和蛋品质的影响,本试验将720羽300日龄罗曼蛋鸡随机分成5组,每组3个重复,每个重复48羽。对照组饲粮为色氨酸含量为0.16%的玉米-豆粕型基础饲粮,4个试验组饲粮为通过在基础饲粮中添加色氨酸使色氨酸水平分别达到0.20%、0.24%、0.28%和0.32%的饲粮,试验期为49d。结果表明:0.20%水平组产蛋率最高,较其他试验组及对照组分别提高了2.18%(P0.05);0.20%水平组鸡蛋蛋白高度和哈氏单位分别提高了6.69%(P<0.05)、2.20%(P<0.05);试验组血清尿素氮(SUN)含量显著减少(P<0.05),0.20%水平组血清总蛋白与白蛋白含量显著高于其他各组(P<0.05);0.20%、0.24%水平组血清中促卵泡素(FSH)含量分别比对照组提高了14.69%(P<0.05)、11.88%(P<0.05),雌二醇(E2)水平提高了20.74%(P<0.05)、15.56%(P<0.05)。结果提示:色氨酸主要通过促性腺激素释放和提高饲料蛋白质利用率等途径提高蛋鸡的生产性能,蛋鸡玉米-豆粕型饲粮色氨酸适宜水平为0.20%。

关键词：蛋鸡生产性能色氨酸蛋品质

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Evolution of Biofilm and Its Effect on Microstructure of Mortar Surfaces in Simulated Seawater

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 234-243页

作者：荣辉 yu Chenglong 张颖 School of Materials Science and Engineering Tianjin Chengjian UniversityTianjin 300384China Tianjin Key Laboratory of Building Green Functional Materials Tianjin Chengjian UniversityTianjin 300384China

To explore the role of biofilm formation on the corrosion of marine concrete structures, we investigated the attachment of biofilm on mortar surfaces in simulated seawater and the influence of biofilm on the microstructure of mortar surfaces. The results show that the evolution of biofilm on mortar surfaces in simulated seawater is closely related to the corrosion suffered by the mortar, and the process of biofilm attachment and shedding is continuous and cyclical. It is found that the specimens in the absence of biofilm attachment are more severely eroded internally by the corrosive medium in simulated seawater than those in the presence of biofilm attachment. For the specimens without biofilm attachment, after 60 days, gypsum forms,and after 120 days, the number of pores in the mortar is reduced. In contrast, for the specimens in the presence of biofilm attachment, gypsum could only be detected after 90 days, and fewer pores are filled. Therefore, the formation of biofilm could delay the invasion of the corrosive medium into the interior of mortar during the evolution of biofilm on mortar surfaces, mitigating the corrosion of mortars in seawater.

关键词： biofilm attachment mortar sulfur-oxidizing bacteria gypsum simulated seawater microstructure

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Current status and trends in small nucleic acid drug development:Leading the future

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Acta Pharmaceutica Sinica B 2024年第9期14卷 3802-3817页

作者： yuxi Miao Chen Fu Zhaojin yu Lifeng yu yu Tang Minjie Wei Department of Pharmacology School of PharmacyChina Medical UniversityShenyang 110122China Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation China Medical UniversityShenyang 110122China Liaoning Medical Diagnosis and Treatment Center Shenyang 110000China Department of Oncology Cancer Hospital of China Medical UniversityLiaoning Cancer Hospital and InstituteShenyang 110042China

Small nucleic acid drugs,composed of nucleotides,represent a novel class of pharmaceuticals that differ significantly from conventional small molecule and antibody-based *** agents function by selectively targeting specific genes or their corresponding messenger RNAs(mRNAs),further modulating gene expression and regulating translation-related *** examples within this category include antisense oligonucleotides(ASO),small interfering RNAs(siRNAs),micro-RNAs(miRNAs),and *** emergence of small nucleic acid drugs as a focal point in contemporary biopharmaceutical research is attributed to their remarkable specificity,facile design,abbreviated development cycles,expansive target spectrum,and prolonged *** challenges such as poor stability,immunogenicity,and permeability issues have been addressed through the integration of chemical modifications and the development of drug delivery *** review provides an overview of the current status and prospective trends in small nucleic acid drug *** with a historical context,we introduce the primary classifications and mechanisms of small nucleic acid ***,we delve into the advantages of the *** and Drug Administration(FDA)approved drugs and mainly discuss the challenges encountered during their *** from researching chemical modification and delivery system that efficiently deliver and enrich small nucleic acid drugs to target tissues,promoting endosomal escape is a critical scientific question and important research direction in siRNA drug *** directions in this field will prioritize addressing these challenges to facilitate the clinical transformation of small nucleic acid drugs.

关键词： Small nucleic acid drugs Oligonucleotide drugs siRNA ASO miRNA Aptamer RNAi Drug development

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Mobility and dynamic erosion process of granular flow:insights from numerical investigation using material point method

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Journal of Mountain Science 2024年第8期21卷 2713-2738页

作者： yu Fangwei SU Lijun LI Xinpo ZHAO yu Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610299China University of Chinese Academy of Sciences Beijing 100049China China-Pakistan Joint Research Center on Earth Sciences Islamabad 45320Pakistan Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing 100101China College of Civil Engineering and Architecture Zhejiang UniversityHangzhou 310058China MOE Key Laboratory of Soft Soil and Geoenvironmental Engineering Zhejiang UniversityHangzhou 310058China

In order to understand the dynamics of granular flow on an erodible base soil,in this paper,a series of material point method-based granular column collapse tests were conducted to investigate numerically the mobility and dynamic erosion process of granular flow subjected to the complex settings,i.e.,the aspect ratio,granular mass,friction and dilatancy resistance,gravity and presence of water.A set of power scaling laws were proposed to describe the final deposit characteristics of granular flow by the relations of the normalized run-out distance and the normalized final height of granular flow against the aspect ratio,being greatly affected by the complex geological settings,e.g.,granular mass,the friction and dilatancy resistance of granular soil,and presence of water in granular *** index of the coefficient of friction of granular soil was defined as a ratio of the target coefficient of friction over the initial coefficient of friction to quantify the scaling extent of friction change(i.e.,friction strengthening or weakening).There is a characteristic aspect ratio of granular column corresponding to the maximum mobility of granular flow with the minimum index of the apparent coefficient of *** index of the repose coefficient of friction of granular flow decreased gradually with the increase in aspect ratio because higher potential energy of granular column at a larger aspect ratio causes a larger kinetic energy of granular soil to weaken the friction of granular soil as a kind of velocity-related friction *** increase in granular mass reduces gradually the indexes of the apparent and repose coefficients of friction of granular soil to enhance the mobility of granular *** mobility of granular flow increases gradually with the decrease in friction angle or increase in dilatancy angle of granular ***,the increase of gravity accelerates granular flow but showing the same final deposit profile without any dependence on ***

关键词： Column collapse Granular flow Granular soil Material point method Mobility Numerical tests

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