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Optimization of the co-closing law of guide vanes and blades for bulb turbines based on CFD

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Journal of Hydrodynamics 2024年第2期36卷 363-377页

作者： Hui Liu Yun-fa Lin Yong-guang Cheng Song Xue Mao-jia Tang Jian Zhang Jia-yi fan State Key Laboratory of Water Resources Engineering and Management Wuhan UniversityWuhan430072China Dongfang Electric Machinery Co. Ltd.Deyang618000China

The load rejection transient process of bulb turbine units is critical to safety of hydropower stations,and determining appropriate closing laws of guide vanes(GVs)and runner blades(RBs)for this process is of *** this study,we proposed a procedure to optimize the co-closing law of GVs and RBs by using computational fluid dynamics(CFD),combined with the design of experiment(DOE)method,approximation model,and genetic optimization *** sensitivity of closing law parameters on the histories of head,speed,and thrust was analyzed,and a two-stage GVs’closing law associating with a linear RBs’closing law was *** results show that GVs dominate the transient characteristics by controlling the change of *** GVs’first-stage closing speed while shortening first-stage closing time can not only significantly reduce the maximum rotational speed but also suppress the water hammer pressure;slowing GVs’second-stage closing speed is conducive to controlling the maximum reverse axial *** directly affect the runner *** RBs’closing speed can further reduce the rotational speed and the maximum reverse axial *** safety margin of each control parameter,flow patterns,and pressure pulsations of a practical hydropower station were all improved after optimization,demonstrating the effectiveness of this method.

关键词： Bulb turbine load rejection transient process double regulation closing law optimization computational fluid dynamics(CFD)

Subclinical paraganglioma of the retroperitoneum:A case report

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World Journal of Clinical Cases 2024年第15期12卷 2672-2677页

作者： Li-Min Kang fa-Kun Yu Fu-Wei Zhang Lei Xu Department of Hepatobiliary and Pancreatic Surgery Puer People's HospitalPuer 665000Yunnan ProvinceChina

BACKGROUnD Paraganglioma(PGL)located in the retroperitoneum presents challenges in diagnosis and treatment due to its hidden location,lack of specific symptoms in the early stages,and absence of distinctive manifestations on *** SUMMARY A 56-year-old woman presented with a left upper abdominal mass discovered 1 wk ago during a physical *** did not have a history of smoking,alcohol consumption,or other harmful habits,no surgical procedures or infectious diseases,and had a 4-year history of *** admission,she did not exhibit fever,vomiting,or abdominal *** examination indicated mild percussion pain in the left upper abdomen,with no palpable enlargement of the liver or *** tests and tumor markers showed no significant *** computed tomography and magnetic resonance imaging of the upper abdomen revealed a cystic solid mass in the left epigastrium measuring approximately 6.5 cm×4.5 cm,with inhomogeneous enhancement in the arterial phase,closely associated with the lesser curvature of the stomach and the *** patient underwent laparoscopic resection of the retroperitoneal mass,which was successfully removed without tumor rupture.A 12-month postoperative follow-up period showed good *** This case report details the successful laparoscopic resection of a retroperitoneal subclinical PGL,resulting in a good recovery observed at the 12-month ***,the patient also experienced unexpected cure of hypertensive disease.

关键词： Paraganglioma Retroperitoneal anatomy Subclinical Pheochromocytoma Laparoscopy Case report

The centrosymmetric to non-centrosymmetric transformation induced by alkaline-earth cations producing infrared nonlinear optical AeMn_(6)Ga_(6)S_(16)(Ae=Ca,Sr)

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Science China Chemistry 2024年第9期67卷 2941-2948页

作者： Yang-Ping Zhang Shao-Min Pei Wen-fa Chen Bin-Wen Liu Xiao-Ming Jiang Guo-Cong Guo State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou 350108China School of Physical Science and Technology Shanghai Tech UniversityShanghai 201210China

non-centrosymmetric(nCS)structure is an indispensable prerequisite for second-order nonlinear optical(nLO)***,the mainstream approach for designing new nCS structures still relies on chemical substitution,necessitating an urgent infusion of fresh *** this work,two isomorphic sulfides AeMn_(6)Ga_(6)S_(16)(Ae=Ca,1;Sr,2)are afforded by modifying the skeleton of centrosymmetric(CS)Mn_(2)Ga_(2)S_(5) via introducing strong electropositive alkaline-earth ***,the incorporation of Ca^(2+)/Sr^(2+)cations allows the elementary[MnGaS_(9)]_(∞)chains to reconfigure into bumpy[MnS_(6)]-[GaS_(4)]layers in a new engagement manner,thus enabling the conversion from CS to nCS *** modifications cause not only strong second-harmonic generation(SHG)responses(~1.5×benchmark AgGaS_(2)@1,700 nm),but also significantly feasible bandgaps(2.60-2.64 e V)compared to the sulfide Mn_(2)Ga_(2)S_(5)(1.36 e V),which ultimately facilitate ultrahigh laser-induced damage thresholds(4.4-6.6×AgGaS_(2)@1,064 nm for compounds 1 and 2).The present study offers an ingenious approach for the transformation of CS to nCS structure.

关键词： second-harmonic generation non-centrosymmetrical structure nLO functional motif solid-state method

Y–Z deformable magnetic ring for the treatment of rectal stricture: A case report and review of literature

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World Journal of Gastroenterology 2024年第6期30卷 599-606页

作者： Miao-Miao Zhang Huan-Chen Sha Yuan-fa Qin Yi Lyu Xiao-Peng Yan Department of Hepatobiliary Surgery The First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710061Shaanxi ProvinceChina national Local Joint Engineering Research Center for Precision Surgery&Regenerative Medicine The First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710061Shaanxi ProvinceChina

BACKGROUnD Treatment of postoperative anastomotic stenosis for colorectal cancer is often challenging,especially for patients who do not respond well to *** cases where patients have undergone an enterostomy,the stenosis can be easily resolved through magnetic ***,common magnetic compre-ssion techniques cannot be performed on those without *** design-ed a novel Y–Z deformable magnetic ring(Y–Z DMR)and successfully applied it to a patient with a stenosis rectal anastomosis and without enterostomy after rectal cancer *** SUMMARY We here report the case of a 57-year-old woman who had undergone a laparo-scopic radical rectum resection(Dixon)for rectal ***,she started facing difficulty in defecation 6 months after *** colonoscopy indicated stenosis of the rectal *** balloon dilation was performed six times on ***,the stenosis still showed a trend of gradual *** the patient did not undergo an enterostomy,the conventional endoscopic magnetic compression technique could not be ***,we imple-mented a Y–Z DMR implemented through the anus under single *** magnetic ring fell off nine days after the operation and the rectal stenosis was *** patient was followed up for six months and reported good *** The Y–Z DMR deformable magnetic ring is an excellent treatment strategy for patients with rectal stenosis and without enterostomy.

关键词： Anastomotic stenosis Colorectal cancer Magnetosurgery Magnetic compression technique Magnetic surgery clinic Case report

Sandwich structures with tapered tubes as core:A quasi-static investigation

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Defence Technology（防务技术） 2024年第3期33卷 447-462页

作者： Xinmei Xiang Dehua Shao Xin Zhang Umer Sharif ngoc San ha Li Xiang Jing Zhang Jiang Yi School of Civil Engineering Guangzhou UniversityGuangzhouChina Department of Mechanics and Aerospace Engineering Southern University of Science and TechnologyShenzhenGuangdongChina School of Engineering Centre for Innovative Structures and MaterialsRMIT UniversityMelbourneAustralia China Southern Airlines Co. LtdShenzhen BranchShenzhen518000China

In this article,the experimental and finite element analysis is utilized to investigate the quasi-static compression features of sandwich constructions built with tapered tubes.3D printing technology was utilized to create the hollow centers of the tapering tubes,with and without *** results demonstrate that the energy absorption(EA)and specific energy absorption(SEA)of the single corrugated tapered tube sandwich are 51.6% and 19.8% higher,respectively,than those of the conical tube ***,the results demonstrate that energy absorbers can benefit from corrugation in order to increase their ***,the tapered corrugated tubes'resistance to oblique impacts was *** to a straight tube,the tapered tube is more resistant to oblique loads and has a lower initial peak crushing force(PCF),according to numerical *** conducting a parametric study,it was discovered that the energy absorption performance of the sandwich construction is significantly affected by the amplitude,number of corrugations,and wall *** and SEA of DTS with corrugation number of 8 increased by 17.4%and 29.6%,respectively,while PCF decreased by 9.2% compared to DTS with corrugation number of 10.

关键词： Sandwich structure Corrugated tube Tapered tube Quasi-static Energy absorption

Acoustofluidic separation of prolate and spherical micro-objects

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Microsystems & nanoengineering 2024年第1期10卷 217-230页

作者： Muhammad Soban Khan Mushtaq Ali Song ha Lee Keun Young Jang Seong Jae Lee Jinsoo Park Department of Mechanical Engineering Chonnam National University77 Yongbong-roBuk-guGwangju 61186Republic of Korea Department of Polymer Engineering The University of Suwon17 Wauan-gilBongdam-eupHwaseongGyeonggi 18323Republic of Korea

Most microfluidic separation techniques rely largely on object size as a separation *** ability to separate micro-objects based on their shape is crucial in various biomedical and chemical ***,we develop an ondemand,label-free acoustofluidic method to separate prolate ellipsoids from spherical microparticles based on traveling surface acoustic wave-induced acoustic radiation force and *** freely rotating non-spherical microobjects were aligned under the progressive acoustic field by the counterrotating radiation torque,and the major axis of the prolate ellipsoids was parallel to the progressive wave *** specific alignment of the ellipsoidal particles resulted in a reduction in the cross-sectional area perpendicular to the wave *** a consequence,the acoustic backscattering decreased,resulting in a decreased magnitude of the radiation *** the variation in radiation force,which depended on the micro-object morphology enabled the acoustofluidic shape-based *** conducted numerical simulations for the wave scattering of spherical and prolate objects to elucidate the working mechanism underlying the proposed method.A series of experiments with polystyrene microspheres,prolate ellipsoids,and peanut-shaped microparticles were performed for *** quantitative analysis of the separation efficiency,we confirmed the high purity and high recovery rate of the proposed acoustofluidic shapebased separation of *** a bioparticle,we utilize Thalassiosira eccentrica to perform shape-based separation,as the species has a variety of potential applications in drug delivery,biosensing,nanofabrication,bioencapsulation and immunoisolation.

关键词： separation spherical rotating

Calibration and experimental verification of discrete element parameters of Panax notoginseng root

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International Journal of Agricultural and Biological Engineering 2024年第4期17卷 13-23页

作者： Kaiting Xie Zhaoguo Zhang fa’an Wang Xiaolan Yu Chenglin Wang Shifei Jiang faculty of Mechanical and Electrical Engineering Kunming University of Science and TechnologyKunming 650500China faculty of Modern Agricultural Engineering Kunming University of Science and TechnologyKunming 650500China Guizhou Agricultural Machinery Technology Promotion Station Guiyang 550003China Yunnan Tobacco Machinery Co. LtdKunming 650100China

Existing discrete element method-based simulation analysis of Panax notoginseng root soil separation still has the challenge to get the accurate and reliable basic parameters,which are necessary for discrete element *** this paper,the *** roots suitable for harvesting period were taken as the experimental *** using 3D scanning reverse modeling technology and EDEM software to establish the discrete element model of ***,based on which,the physical and virtual tests were carried out to calibrate the simulation ***,the basic physical parameters(density,triaxial geometric size,moisture content,shear modulus,and elastic modulus)and contact coefficients(static friction coefficient,rolling friction coefficient,and crash recovery coefficient between *** roots and 65Mn steel)were measured by physical ***,treating the contact coefficients of *** roots as the influence factor,the steepest uphill test,and four factors combing five levels of rotational virtual simulation are *** measured relative error accumulation angle and simulation accumulation angle are set as the performance *** results show that the static friction coefficient,rolling friction coefficient,crash recovery coefficient,and surface energy coefficient of *** roots are 0.55,0.35,0.16,and 19.5 J/m2,*** calibration results as parameters of the vibration separation simulation test of *** soil,the Box-Behnken vibration separation simulation tests were carried out,in which the vibration frequency,inclination angle,and vibration amplitude of separation device as factors,screening rate and damage rate of *** soil complex are regarded as *** results show that the optimal operating parameters of the separation device are the vibration frequency of 10 Hz,the inclination angle of 5°,and the amplitude of 6 *** on the optimal operation parameters,the discrete element

关键词： Panax notoginseng root EDEM parameter calibration separation test

Effect of Meteorological Data Assimilation on Regional Air Quality Forecasts over the Korean Peninsula

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Journal of Meteorological Research 2024年第2期38卷 262-284页

作者： Yunjae CHO Hyun Mee KIM Eun-Gyeong YAnG Yonghee LEE Jae-Bum LEE Soyoung ha Department of Atmospheric Sciences Yonsei UniversitySeoul 03722Republic of Korea Air Quality Forecasting Center National Institute of Environmental ResearchIncheon 22689Republic of Korea national Center for Atmospheric Research BoulderCO 80305USA University of Maryland Baltimore County BaltimoreMD 21250USA Global Modeling and Assimilation Office NASA Goddard Space Flight CenterGreenbeltMD 20771USA

The Weather Research and Forecasting model coupled with Chemistry(WRF-Chem),a type of online coupled chemistry-meteorology model(CCMM),considers the interaction between air quality and meteorology to improve air quality *** data assimilation(DA)can be used to reduce uncertainty in meteorological field,which is one factor causing prediction uncertainty in the *** this study,WRF-Chem and three-dimensional variational DA were used to examine the impact of meteorological DA on air quality and meteorological forecasts over the Korean *** nesting model domains were configured over East Asia(outer domain)and the Korean Peninsula(inner domain).Three experiments were conducted by using different DA domains to determine the optimal model domain for the meteorological *** the meteorological DA was performed in the outer domain or both the outer and inner domains,the root-mean-square error(RMSE),bias of the predicted particulate matter(PM)concentrations,and the RMSE of predicted meteorological variables against the observations were smaller than those in the experiment where the meteorological DA was performed only in the inner *** indicates that the improvement of the synoptic meteorological fields by DA in the outer domain enhanced the meteorological initial and boundary conditions for the inner domain,subsequently improving air quality and meteorological *** to the experiment without meteorological DA,the RMSE and bias of the meteorological and PM variables were smaller in the experiments with *** effect of meteorological DA on the improvement of PM predictions lasted for approximately 58-66 h,depending on the ***,the uncertainty reduction in the meteorological initial condition by the meteorological DA contributed to a reduction of the forecast errors of both meteorology and air quality.

关键词： meteorological data assimilation regional air quality forecast particulate matter concentration optimal model domain forecast error WRF-Chem

The coupling control of biological precursors and environmental factors onβ-carotane enrichment in alkaline lacustrine source rocks:A case study from the Fengcheng formation in the western Junggar Basin,nW China

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Petroleum Science 2024年第2期21卷 836-854页

作者： Mao-Guo Hou Ming Zha Hua Liu hai-Lei Liu Jiang-Xiu Qu Ablimit Imin Xiu-Jian Ding Zhong-fa Jiang School of Geosciences China University of PetroleumQingdaoShandong266580China Research Institute of Exploration and Development Xinjiang Petroleum Administration BureauKaramayXinjiang834000China

The organic-rich mudstones and dolostones of the Permian Fengcheng Formation(Fm.)are typically alkaline lacustrine source rocks,which are typified by impressively abundantβ-*** β-carotane has been well acknowledged as an effective indicator of biological sources or depositional ***,the specific biological sources of β-carotane and the coupling control of biological sources and environmental factors on the enrichment of β-carotane in the Fengcheng *** *** on a comprehensive investigation of the bulk,molecular geochemistry,and organic petrology of sedimentary rocks and the biochemistry of phytoplankton in modern alkaline lakes,we proposed a new understanding of the biological precursors of β-carotane and elucidated the enrichment mechanism of β-carotane in the Fengcheng *** results show that the biological precursors crucially control the enrichment of β-carotane in the Fengcheng *** haloalkaliphilic cyanobacteria are the primary biological sources of β-carotane,which is suggested by a good positive correlation between the 2-methylhopane index,7-+8-methyl heptadecanes/C_(max),C_(29%),and β-carotane/C_(max)in sedimentary rocks and the predominance of cyanobacteria with abundantβ-carotene in modern alkaline *** enrichment of β-carotane requires the reducing condition,and the paleoredox state that affects the enrichment of β-carotane appears to have a *** paleoclimate conditions do not considerably impact the enrichment of β-carotane,but they have some influence on the water's paleosalinity by affecting evaporation and *** it does not directly affect the enrichment of β-carotane in the Fengcheng Fm.,paleosalinity does have an impact on the cyanobacterial precursor supply and the preservation conditions.

关键词： β-carotane enrichment Cyanobacterial input Environmental impact Alkaline lacustrine source rocks The Fengcheng formation