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颈外静脉穿刺在降低CT增强扫描中造影剂外溢的应用价值

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四川生理科学杂志 2024年第4期46卷 894-896页

作者：魏岭娜钱伟军李立冯中全开封市中心医院医学影像科河南开封475000

目的:探讨颈外静脉穿刺在降低CT增强扫描中造影剂外溢的应用。方法:选取我科2020年9月至2022年9月期间286例行CT增强扫描诊断的患者作为研究对象,随机分为对照组143例(采用前臂桡侧静脉穿刺)和研究组143例(采用颈外静脉穿刺)。对比两组... 详细信息

目的:探讨颈外静脉穿刺在降低CT增强扫描中造影剂外溢的应用。方法:选取我科2020年9月至2022年9月期间286例行CT增强扫描诊断的患者作为研究对象,随机分为对照组143例(采用前臂桡侧静脉穿刺)和研究组143例(采用颈外静脉穿刺)。对比两组患者穿刺情况、造影剂输注畅通情况及成像质量、穿刺部位不良反应发生率。结果:研究组穿刺耗费时间较对照组短,一次性穿刺成功率较对照组高,漏液率较对照组低(P<0.05);研究组造影剂推注时间较对照组短,CT值较对照组高(P<0.05);研究组穿刺部位不良反应发生率较对照组低(P<0.05)。结论:相较于前臂桡侧静脉穿刺,颈外静脉穿刺不仅能提高一次性穿刺成功率,提扫描图像质量,还能降低CT增强扫描中造影剂外溢和穿刺部位不良反应。

关键词：颈外静脉穿刺增强CT 造影剂外溢外周静脉留置

Charge-controlled compositional/microstructural regulations and electrochemical actuation performance of bulk nanoporous Ni-Pd alloys

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Rare Metals 2024年第10期43卷 5305-5317页

作者： Fu-quan Tan Qing-Guo Bai Bin Yu Jian-feng Wang zhong-Hua Zhang Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education) School of Materials Science and EngineeringShandong University School of Applied Physics and Materials Wuyi University Ira A.Fulton School of Engineering Arizona State University

Bulk nanoporous （np） metallic actuators have attracted increasing attention due to their large strain and low stimulation ***,studies focusing upon the combined effect of composition and structure on the actuation performance of metallic actuators are relatively scarce,and its underlying mechanism needs to be clarified Herein,a series of bulk np-NiPd samples with differen compositions and microstructures were fabricated using a dealloying-coarsening-dealloying strategy and chargecontrolled electrochemical dealloying,and the process involves only one component of precursor *** has been found that the np-NiPd cubes show a composition/structure-dependent mechanical property and electrochemical actuation ***,the npNi70Pd30sample with a homogeneously porous structure and good network connectivity exhibits significantly larger strain amplitude and faster strain rate than other hierarchically porous NiPd samples (np-Ni50Pd50and npNi20Pd80).Moreover,the np-Ni70Pd30sample demonstrates good actuation stability with high strain retention after hundreds of ***,the maximum strain amplitude （1.17%） is even comparable to that of advanced leadfree piezoceramic,and the maximum strain rate exceeds those of many reported metallic actuator *** work indicates that good network connectivity plays a vita role in facilitating large/fast strain response in metallic actuators.

关键词： Actuation stability Bulk nanoporous NiPd Electrochemical dealloying Good network connectivity Metallic actuators

AN INVESTIGATION OF TURBULENT HEAT TRANSFER IN CHANNEL FLOWS BY LARGE EDDY SIMULATION

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Journal of Hydrodynamics 2002年第2期14卷 29-35页

作者： Dong Yu-hong, zhong feng-quan, Lu Xi-yun, Zhuang Li-xian Department of Mechanics and Mechanical Engineering, University of Science and Technology of China, Hefei 230026, China Department of Mechanics and Mechanical Engineering University of Science and Technology of China Hefei 230026 China

Large Eddy Simulation (LES) of fully developed turbulent channel flow with heat transfer was performed to investigate the effects of the Reynolds number on the turbulence behavior. In the present study, the bottom wall of the channel was cooled and the top wall was heated. The Reynolds numbers, based on the central mean-velocity and the half-width of the channel, were chosen as 4000, 6000, 10 4 and 2×10 4, and the Prandtl number as 1.0. To validate our calculations, the present results were compared with available data obtained by Direct Numerical Simulation (DNS), which proves to be in good agreement with each other. To reveal the effects of the Reynolds number, some typical quantities, including the velocity fluctuations, temperature fluctuation, heat fluxes and turbulent Prandtl number, were studied.

关键词： Large Eddy Simulation (LES) turbulent channel flow Subgrid Scale (SGS) model heat transfer stratified turbulence

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Numerical simulation of transient characteristics in a bulb turbine during the load rejection process

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Journal of Hydrodynamics 2024年第1期36卷 170-183页

作者： Yue Lu Yu-quan Zhang zhong-wei He Yuan Zheng College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing210098China College of Energy and Electrical Engineering Hohai UniversityNanjing210098China Huadong Engineering Corporation Ltd. Hangzhou311122China

To evaluate the safety of the bulb tubular turbine,the dynamic hydraulic characteristics of a hydropower station system during the load rejection process are studied through numerical simulations and a prototype *** the developed model,a dynamic grid technology(DGT)controls the closure of the guide vane and the blade,whilst the moment balance equation and the user-defined function(UDF)provide the runner’s rotation *** 3-D transient simulation method can well predict the rotation speed and mass flow curves in the state of load *** simulation outcomes of the system performance are basically consistent with the measurement data of the *** observed,the runner is subjected to the reversely increased torque and axial force,the system is in a braking phase,and the maximum speed peaks at 144.6%of the rated ***,the internal flow of the runner is greatly affected by the closure of the guide vane,and the draft tube forms an eccentric spiral vortex *** breaks downstream,aggravating the instability of the draft ***,the transient characteristics span for the first five seconds,demonstrating the importance of establishing an efficient governing *** obtained results are useful for designing the turbine’s flow channel with a double regulating function and comprehending the turbine’s transient characteristics.

关键词： Bulb tubular turbine load rejection numerical simulation dynamic grid prototype test

Thermal-force control ability under variation of electromagnetic stick structure parameters in RPECT

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Journal of Iron and Steel Research International 2024年第1期31卷 224-236页

作者： Ting-song Yang Wen-quan Sun feng-shan Du An-rui He quan Yang National Engineering Research Center of Advanced Rolling and Intelligent Manufacturing University of Science and Technology BeijingBeijing100083China Institute of Engineering and Technology University of Science and Technology BeijingBeijing100083China College of Mechanical Engineering Yanshan UniversityQinhuangdao066004HebeiChina

Thermal-force driving of roll profile electromagnetic control technology(RPECT),which can be used to adjust the roll profile,can be affected by the sequential temperature rise between the electromagnetic stick(ES)and electromagnetic control *** to the limited space of ES and induction coil,the cross-sectional area of induction coil can be inevitably affected by changing the size of the ES induction zone,which can further change the energy input under the same electromagnetic parameters,the temperature rising effect and the bulging *** investigate this phenomenon,the effects of the radius of the induction zone on the thermal-force contribution ratio,the heating ability of ES and the temperature distribution were analyzed through an electromagnetic-thermal-structural finite element *** ensure that the results are applicable to RPECT,the thermal energy conversion ability and thermal-force roll crown control ability under different lengths of the induction zone were *** was found that whether the current density regulation mode or the current frequency regulation mode is adopted,the cases with 20 or 25 mm radius of the induction zone have the great thermal energy conversion ability and the good thermal-force roll crown control *** reasonable adjustment of the length of the induction zone can reduce the radius required for the maximum energy efficiency *** with the results of the simulation analysis,the optimization of ES based on the control ability maximization requirement is achieved,which provides the base for the design and configuration of ES in RPECT.

关键词： Roll profile electromagnetic control technology Electromagnetic stick Electromagnetic control roll Induction area Thermal-force driving

The association and underlying mechanism of the digit ratio(2D:4D)in hypospadias

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Asian Journal of Andrology 2024年第4期26卷 356-365页

作者： Yu Ding Zu-quan Chen Wen-feng Pan Hao-Jie Chen Min Wu Yi-Qing Lyu Hua Xie Yi-Chen Huang zhong-zhong Chen Fang Chen Department of Urology Shanghai Children’s HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai 200062China Urogenital Development Research Center Shanghai Children’s HospitalSchool of MedicineShanghai Jiao Tong UniversityShanghai 200062China Clinical Research Center for Hypospadias Pediatric CollegeShanghai Jiao Tong University School of MedicineShanghai 200062China.

The second-to-fourth digit(2D:4D)ratio is thought to be associated with prenatal androgen ***,the relationship between the 2D:4D ratio and hypospadias is poorly understood,and its molecular mechanism is not *** this study,by analyzing the hand digit length of 142 boys with hypospadias(23 distal,68 middle,and 51 proximal)and 196 controls enrolled in Shanghai Children’s Hospital(Shanghai,China)from December 2020 to December 2021,we found that the 2D:4D ratio was significantly increased in boys with hypospadias(P<0.001)and it was positively correlated with the severity of the *** was further verified by the comparison of control mice and prenatal low testosterone mice model obtained by knocking out the risk gene(dynein axonemal heavy chain 8[DNAH8])associated with ***,the discrepancy was mainly caused by a shift in *** characterization of a mouse model validated that low testosterone levels during pregnancy can impair the growth and development of *** mechanistic explorations revealed that during the androgen-sensitive window,the downregulation of the androgen receptor(AR)caused by low testosterone levels,as well as the suppressed expression of chondrocyte proliferation-related genes such as Wnt family member 5a(Wnt5a),Wnt5b,Smad family member 2(Smad2),and Smad3;mitochondrial function-related genes in cartilage such as AMP-activated protein kinase(AMPK)and nuclear respiratory factor 1(Nrf-1);and vascular development-related genes such as myosin light chain(MLC),notch receptor 3(Notch3),and sphingosine kinase 1(Sphk1),are responsible for the limitation of 4D growth,which results in a higher 2D:4D ratio in boys with hypospadias via decreased endochondral *** study indicates that the ratio of 2D:4D is a risk marker of hypospadias and provides a potential molecular mechanism.

关键词： androgen receptor digit ratio(2D:4D) endochondral ossification hypospadias testosterone level

Effect of Mo and cold forging deformation on strength and ductility of cobalt-based alloy L605

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Journal of Iron and Steel Research International 2024年第7期31卷 1811-1823页

作者： zhong-lin Wang Zhi-hua Gong quan Li Han-sheng Bao School of Materials and Metallurgy Inner Mongolia University of Science and TechnologyBaotou 014017Inner MongoliaChina Institute of Special Steels Central Iron and Steel Research Institute Co.Ltd.Beijing 100081China

Mo element was added to cobalt-based alloy L605,and cold forging deformation was *** effects of the addition and cold forging deformation on the microstructure and mechanical properties of the alloy were studied by thermodynamic calculation,electron backscatter diffraction,transmission electron microscopy,and X-ray *** stacking fault energy(SFE)of the alloy decreased after the addition,and the formation of stacking faults and intersections were promoted to improve the strength and *** tensile strength of the alloy with Mo increased from 1190 to 1702 MPa after 24%cold deformation,producing significant work *** strengthening mechanism is strain-induced martensitic transformation(SIMT)and deformation *** alloy,combined with Mo and after 24%deformation,had both high strength and ductility in comparison with the original cobalt-based alloy *** is attributed to the lower SFE which caused the increase in stacking fault *** the tensile process,theε-hcp phase was easily generated at the stacking fault to reduce the stress concentration and increase the *** SIMT by adjusting the density of stacking faults can improve the mechanical properties of cobalt-based ***ε-hcp phase,the interaction between deformation twins and dislocations,and the interaction between e-hcp phases during cold forging deformation caused local stress concentration,lowering ductility and toughness.

关键词： Cobalt-based alloy-Stacking fault energy Strain-induced martensitic transformation Deformation twin Cold forging deformation

Peer-to-Peer Trading in Distribution Systems with the Utility's Operation

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 629-638页

作者： Xuanyi Xiao feng Wang Mohammad Shahidehpour Yujia Zhai quan Zhou Department of Electrical and Information Engineering Hunan UniversityChangshaChina Robert W.Galvin Center for Electricity Innovation Ilinois Institute of TechnologyChicagoIL60616USA

To realize a liberalized peer-to-peer (P2P) electricity market in distribution systems with network security, this paper develops a general framework for P2P trading in distribution systems with the utility's operation. The model is formulated as a bi-level programming. The utility's operation is an upper level problem, where a calculation method of network usage charges for P2P trading is also proposed. Peers' P2P trading is a lower level problem. An iterative algorithm based on analytical target cascading (ATC) is proposed to solve the model, where the interactions between utility and peers are presented. Numerical results on the IEEE 33-bus system demonstrate that the proposed method realizes a liberalized P2P market and ensures network security in distribution systems.

关键词： Distribution system peer-to-peer trading electricitymarket distributed energyresources(DERs) analytical target cascading(ATC)

解离效应对超燃冲压发动机燃烧与传热的影响特性研究

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推进技术 2022年第5期43卷 239-245页

作者：徐雪睿仲峰泉中国科学院力学研究所高温气体动力学国家重点实验室北京100190 中国科学院大学工程科学学院北京100049

为了分析高温解离效应对超燃冲压发动机燃烧和传热的影响,在超声速流动与燃烧一维理论模型的基础上,提出了“解离效率”的概念,建立了一种对高温燃气解离吸热效应进行量化评估的方法和发动机流动理论分析模型。应用该模型对日本宇宙航... 详细信息

为了分析高温解离效应对超燃冲压发动机燃烧和传热的影响,在超声速流动与燃烧一维理论模型的基础上,提出了“解离效率”的概念,建立了一种对高温燃气解离吸热效应进行量化评估的方法和发动机流动理论分析模型。应用该模型对日本宇宙航空研究开发机构M12-02发动机模型进行了研究,定量分析了解离效应对飞行马赫数12条件下超声速燃烧流动与传热的影响特性。研究表明,高温解离效应使得发动机性能损失明显,损失程度与燃料当量比有关。燃料当量比0.5时,氢燃料发动机、乙烯燃料发动机推力和比冲下降6%左右,壁面总热量减少约4%。当量比增加至1.0时,燃烧室内流温度升高,解离效应显著增强,氢燃料发动机、乙烯燃料发动机推力和比冲的损失增至22%左右,壁面总热量下降约16%。

关键词：超声速燃烧理论模型解离效应当量比发动机性能

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