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Flow Loss Mechanism in a Supercritical Carbon Dioxide Centrifugal Compressor at Low Flow Rate Conditions

Journal of Thermal Science 2024年第1期33卷 114-125页

作者： YANG zimu jiang Hongsheng ZHUGE Weilin CAI Ruikai YANG Mingyang CHEN Haoxiang QIAN Yuping ZHANG Yangjun State Key Laboratory of Automotive Safety and Energy Tsinghua UniversityBeijing 100084China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

With the advantages of high efficiency and compact structure,supercritical carbon dioxide(sC02)Brayton cycles have bright prospects for development in energy conversion field.As one of the core components of the power cycle,the centrifugal compressor tends to operate near the critical point(304.13 K,7.3773 MPa).Normally,the compressor efficiency increases as the inlet temperature decreases.When the inlet temperature is close to the critical point,the density increases sharply as the temperature decreases,which results in quickly decreasing of volume flow rate and efficiency reducing.The flow loss mechanism of the sCO_(2) compressor operating at low flow rate is studied in this paper.Computational fluid dynamics(CFD) simulations for sCO_(2)compressor were carried out at various inlet temperatures and various mass flow rates.When the sCO_(2)compressor operates at low volume flow rate,the flow loss is generated mainly on the suction side near the trailing edge of the blade.The flow loss is related to the counterclockwise vortexes generated on the suction side of the main blade.The vortexes are caused by the flow separation in the downstream region of the impeller passage,which is different from air compressors operating at low flow rates.The reason for this flow separation is that the effect of Coriolis force is especially severe for the sCO_(2) fluid,compared to the viscous force and inertial force.At lower flow rates,with the stronger effect of Coriolis force,the direction of relative flow velocity deviates from the direction of radius,resulting in its lower radial component.The lower radial relative flow velocity leads to severe flow separation on the suction side near the trailing edge of the main blade.

关键词： supercritical CO_(2) centrifugal compressor flow loss mechanism Coriolis force

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Effect of ultramicropores and inner space of carbon materials on the capacitive sodium storage performance

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Journal of Energy Chemistry 2022年第10期31卷 35-40,I0002页

作者： zimu jiang Su Zhang Jing Feng Yuting jiang Shichuan Liang Qiqi Li Mengjiao Shi Meng Cao Mingyi Zhang Tong Wei Zhuangjun Fan Key Laboratory of Superlight Materials and Surface Technology Ministry of EducationCollege of Material Science and Chemical EngineeringHarbin Engineering UniversityHarbin 150001HeilongjiangChina State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources College of ChemistryXinjiang UniversityUrumqi 830046XinjiangChina Key Laboratory for Photonic and Electronic Bandgap Materials Ministry of EducationSchool of Physics and Electronic EngineeringHarbin Normal UniversityHarbin 150025HeilongjiangChina State Key Laboratory of Heavy Oil Processing School of Materials Science and EngineeringChina University of PetroleumQingdao 266580ShandongChina

1.Introduction Carbon materials have been widely investigated as the anode materials for Na+storage due to their moderate capacity,good stability,and low cost.The Na+storage mechanisms of carbon are generally classified into diffusion-controlled interlayer insertion/desertion and capacitive-controlled surface adsorption/desorption[1].

关键词： Graphene block Ultramicropores Na^(+)storage Electrochemical kinetic

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Sandwiching Sulfur into the Dents Between N,O Co-Doped Graphene Layered Blocks with Strong Physicochemical Confinements for Stable and High-Rate Li-S Batteries

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Nano-Micro Letters 2020年第11期12卷 13-24页

作者： Mengjiao Shi Su Zhang Yuting jiang zimu jiang Longhai Zhang Jin Chang Tong Wei Zhuangjun Fan Key Laboratory of Superlight Materials and Surface Technology Ministry of EducationCollege of Material Science and Chemical EngineeringHarbin Engineering UniversityHarbin 150001People’s Republic of China Key Laboratory of Energy Materials Chemistry Ministry of EducationKey Laboratory of Advanced Functional MaterialsAutonomous RegionInstitute of Applied ChemistryXinjiang UniversityUrumqi 830046People’s Republic of China State Key Laboratory of Heavy Oil Processing School of Materials Science and EngineeringChina University of PetroleumQingdao 266580People’s Republic of China

The development of lithium-sulfur batteries(LSBs)is restricted by their poor cycle stability and rate performance due to the low conductivity of sulfur and severe shuttle effect.Herein,an N,O co-doped graphene layered block(NOGB)with many dents on the graphene sheets is designed as effective sulfur host for high-performance LSB s.The sulfur platelets are physically confined into the dents and closely contacted with the graphene scaffold,ensuring structural stability and high conductivity.The highly doped N and O atoms can prevent the shuttle effect of sulfur species by strong chemical adsorption.Moreover,the micropores on the graphene sheets enable fast Li^+transport through the blocks.As a result,the obtained NOGB/S composite with 76 wt%sulfur content shows a high capacity of 1413 mAh g^-1 at 0.1 C,good rate performance of 433 mAh g^-1 at 10 C,and remarkable stability with 526 mAh g^-1 at after 1000 cycles at 1 C(average decay rate:0.038%per cycle).Our design provides a comprehensive route for simultaneously improving the conductivity,ion transport kinetics,and preventing the shuttle effect in LSBs.

关键词： Graphene Physicochemical confinement Cycle stability Shuttle effect Li-S batteries

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含光伏与生物质能的生态农业综合能源系统多能协同及低碳运行策略

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中国电机工程学报 2024年第4期44卷 1352-1363,I0009页

作者：姜飞肖昌麟易子木何桂雄郭祺彭星肖国骏长沙理工大学电气与信息工程学院湖南省长沙市410076 中国电力科学研究院有限公司北京市海淀区100192 湖南大学电气与信息工程学院湖南省长沙市410082 国网湖南综合能源服务有限公司湖南省长沙市410007

双碳政策推动下,乡村农业综合能源系统(integrated energy system,IES)的多能耦合关系更加复杂。为实现农业园区可靠运行,提出面向生态农业IES的多能互补与低碳运行优化调度策略。首先,基于农业园区的能量流动关系,建立沼气生产环节、... 详细信息

双碳政策推动下,乡村农业综合能源系统(integrated energy system,IES)的多能耦合关系更加复杂。为实现农业园区可靠运行,提出面向生态农业IES的多能互补与低碳运行优化调度策略。首先,基于农业园区的能量流动关系,建立沼气生产环节、多能耦合供应环节以及柔性负荷需求响应环节的数学模型。其次,考虑光伏、负荷和沼气的不确定性,建立生态农业IES两阶段鲁棒优化模型。模型引入碳排放成本和启停成本,可降低农业生产碳排放,防止机组频繁启停。然后,采用列与约束生成算法(column-and-constraint generation,C&CG),结合强对偶定理与线性化理论实现模型求解。最后,基于江西省某生态牧场IES进行算例仿真,验证所提策略的有效性。仿真结果表明,所提策略可实现生态农业IES的协调运行,提高系统经济性、低碳性和能效性。

关键词：生态农业综合能源鲁棒优化列与约束生成强对偶定理柔性负荷

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脑梗死累及岛叶预示心源性栓塞性卒中风险

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中国神经精神疾病杂志 2024年第2期50卷 76-81页

作者：黄宝资黎建乐李苹萍曹谡涵陈椿勇蒋自牧曾进胜中山大学附属第一医院神经科广东省重大神经疾病诊治研究重点实验室国家临床重点专科和国家重点学科广州510080 广西医科大学第一附属医院神经内科

目的探讨在大脑中动脉供血区脑梗死患者中,病灶累及岛叶是否与心源性栓塞性卒中存在相关性。方法回顾性纳入2020年10月至2023年3月中山大学附属第一医院和广西医科大学第一附属医院卒中中心收治的发病7 d内的大脑中动脉供血区脑梗死... 详细信息

目的探讨在大脑中动脉供血区脑梗死患者中,病灶累及岛叶是否与心源性栓塞性卒中存在相关性。方法回顾性纳入2020年10月至2023年3月中山大学附属第一医院和广西医科大学第一附属医院卒中中心收治的发病7 d内的大脑中动脉供血区脑梗死患者。卒中病因分型分为心源性栓塞型和非心源性栓塞型。病灶是否累及岛叶主要通过磁共振弥散加权成像(DWI)进行确诊。采用单因素和多因素logistic回归分析探讨累及岛叶的脑梗死与心源性栓塞性卒中之间的相关性。结果共纳入大脑中动脉供血区脑梗死患者1585例,其中心源性栓塞型173例(10.9%)和非心源性栓塞型1412例(89.1%)。脑梗死累及岛叶448例(28.3%),其中心源性栓塞组135例(78.0%)和非心源性栓塞组313例(22.2%)。单因素logistic回归分析提示累及岛叶的脑梗死与心源性栓塞性卒中存在相关性(未调整模型:OR=12.474, 95%CI 8.520~18.263,P<0.001)。在调整潜在混杂因素后,两者间仍存在显著相关性(模型3:OR=6.233, 95%CI 3.688~10.543;P<0.001)。此外,累及左侧(模型3:OR=4.977, 95%CI 2.757~8.987,P<0.001)和右侧岛叶的脑梗死(模型3:OR=4.998,95%CI 2.743~9.107,P<0.001)均与心源性栓塞性卒中存在相关性。结论大脑中动脉供血区脑梗死累及岛叶可作为心源性栓塞性卒中的潜在影像学标志。

关键词：岛叶受累心源性栓塞性卒中大脑中动脉供血区脑梗死影像学标志相关性风险非心源性栓塞性卒中

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Investigation on Precooling Effects of 4 K Stirling-Type Pulse Tube Cryocoolers

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Journal of Thermal Science 2019年第4期28卷 714-726页

作者： CAO Qiang LI zimu LUAN Mingkai SUN Zheng TANG Xiao LI Peng jiang Zhenhua WEI Li Institute of Refrigeration and Cryogenics School of Mechanical EngineeringTongji UniversityShanghai 201804China Shanghai Key Laboratory of Vehicle Aerodynamics and Vehicle Thermal Management Systems Tongji UniversityShanghai 201804China Shanghai Institute of Technical Physics Chinese Academy of SciencesShanghai 200083China Department of Electrical Engineering School of Electronics and Information EngineeringTongji UniversityShanghai 201804China

Stirling-type pulse tube cryocoolers(SPTCs)working at liquid-helium temperatures are appealing in space applications because of their promising advantages such as high reliability,compactness,etc.Worldwide efforts have been put in to develop SPTCs operating at liquid-helium temperatures especially with helium-4 as the working fluid.Staged structure is essential to reach such low temperatures.Generally,both the regenerator of the last section and the pulse tube together with the phase shifter are precooled by its upper stage or by external cold source to a low temperature of around 20 K.However,the precooling effects on the regenerator and the pulse tube are synthetic in previous studies,and their independent effects have not been studied clearly.In this manuscript,the precooling effects on the regenerator and on the pulse tube together with the phase shifter are tested independently on a unique-designed precooled SPTC.The tested precooling temperature is between 13.3 K and 22 K,and the no-load refrigeration temperature gets down to 3.6 K.Further analyses and numerical calculations have been carried out.It is found that the influence on the regenerator is remarkable,which is different from previous conclusions.It is also found that the precooling effects on the pulse tube are relatively weak because of the large pressure-induced enthalpy flow of a real gas working at the temperatures near to the critical point.Furthermore,the phase shifting capacity is analyzed with two cases and with both helium-4 and helium-3 as working fluids,and it keeps quite constant after optimizing the frequency and the precooling temperature for each case.The investigation on these independent effects will provide valid reference on the precooling mechanism study of SPTCs working down to liquid-helium temperatures.

关键词： stirling-type pulse tube cryocooler precooling effects liquid-helium temperatures

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Cholesterol transport through the peroxisome-ER membrane contacts tethered by PI（4,5）P2 and extended synaptotagmins

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Science China(Life Sciences) 2019年第9期62卷 1117-1135页

作者： Jian Xiao Jie Luo Ao Hu Ting Xiao Meixin Li Zekai Kong Luyi jiang zimu Zhou Yacheng Liao Chang Xie Beibei Chu Honghua Miao Boliang Li Xiongjie Shi Bao-Liang Song College of Life Sciences the Institute for Advanced StudiesWuhan UniversityWuhan 430072China State Key Laboratory of Molecular Biology Institute of Biochemistry and Cell BiologyShanghai Institutes for Biological SciencesChinese Academy of SciencesShanghai 200031China Shenzhen Institute of Wuhan University Shenzhen 518057China

Most mammalian cells take up cholesterol from low-density lipoproteins(LDLs) via receptor-mediated endocytosis.After reaching lysosomes,LDL-derived cholesterol continues to transport to downstream organelles including the ER for specific structural and functional needs.Peroxisomes are recently found to receive cholesterol from lysosomes through lysosomeperoxisome membrane contacts.However,whether and how cholesterol is conveyed from peroxisomes to the ER remain unknown.Here,by combining high-resolution microscopic analyses and in vitro reconstitution of highly purified organelles or artificial liposomes,we demonstrate that peroxisomes form membrane contacts with the ER through the interaction between peroxisomal PI(4,5)P2 and ER-resident extended synaptotagmin-1,2 and 3(E-Syts).Depletion of peroxisomal PI(4,5)P2 or ESyts markedly decreases peroxisome-ER membrane contacts and induces cholesterol accumulation in lysosomes.Furthermore,we show that cholesterol is delivered from 3H-labeled peroxisomes or PI(4,5)P2-containing liposomes to the ER in vitro,and that the presence of peroxisomes augments cholesterol transfer from lysosomes to the ER.Together,our study reveals a new cholesterol transport pathway along the lysosome-peroxisome-ER membrane contacts in the cell.

关键词： Peroxisome ER membrane contacts E-Syts PI(4,5)P2

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超临界二氧化碳离心压缩机流动特性研究进展

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清华大学学报（自然科学版） 2023年第11期63卷 1791-1807页

作者：杨子木江泓升诸葛伟林钱煜平张扬军清华大学车辆与运载学院汽车安全与节能国家重点实验室北京100084

超临界二氧化碳(supercritical carbon dioxide,S-CO_(2))Brayton循环是中温高压循环,采用该循环可回收利用燃气涡轮和内燃机等交通动力系统的高温排气能量,从而提高动力系统效率。压缩机高效稳定运行对S-CO_(2)Brayton循环的循环性能... 详细信息

超临界二氧化碳(supercritical carbon dioxide,S-CO_(2))Brayton循环是中温高压循环,采用该循环可回收利用燃气涡轮和内燃机等交通动力系统的高温排气能量,从而提高动力系统效率。压缩机高效稳定运行对S-CO_(2)Brayton循环的循环性能起到至关重要的作用。该文从实验、一维流动分析、三维流动特性和流动控制4个方面综述了S-CO_(2)离心压缩机流动特性的研究进展,重点阐述了关于工质临界点附近的剧烈物性变化对压缩机内部流动带来的问题及其研究内容,同时总结了S-CO_(2)离心压缩机流动特性的相关研究,并提出未来S-CO_(2)离心压缩机流动特性的研究重点。

关键词： S-CO_(2)离心压缩机一维流动三维流动特性流动控制临界点

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基于“子母补泻”法探讨针刺五输穴联合阿片类药物治疗中重度胃癌痛的临床疗效研究

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中医肿瘤学杂志 2024年第3期6卷 54-61页

作者：易雨林颖曈江钢辉冯淑兰张正广州中医药大学针灸康复临床医学院广东广州510405 广州中医药大学第一附属医院广东广州510405

目的本研究旨在观察针刺五输穴联合阿片类药物对中重度癌痛的临床疗效。方法将来源于广州中医药大学第一附属医院针灸推拿康复中心及肿瘤中心患者60例随机分成试验组和对照组,每组各30例。对照组仅予阿片类止痛药物,试验组在予阿片类止... 详细信息

目的本研究旨在观察针刺五输穴联合阿片类药物对中重度癌痛的临床疗效。方法将来源于广州中医药大学第一附属医院针灸推拿康复中心及肿瘤中心患者60例随机分成试验组和对照组,每组各30例。对照组仅予阿片类止痛药物,试验组在予阿片类止痛药物的基础上同时给予针刺治疗,7天为1个疗程,共1个疗程,疗程结束2周后进行随访。观察治疗前后及随访时患者的数字疼痛评分量表(Numerical rating scale,NRS)、简化McGill疼痛问卷(SF-MPQ)、肿瘤患者生活质量评分(QOL量表)及治疗期间患者使用阿片类止痛药物总剂量。结果治疗后及随访时两组NRS量表评分、SF-MPQ量表总分均较治疗前有所下降,试验组评分差值较对照组更大,且止痛效果更持久,两组间差异均具有统计学意义(P0.05);而对于重度癌痛,试验组的总体疼痛缓解有效率明显优于对照组,且差异具有统计学意义(P0.05)。治疗前后两组药物使用总剂量结果显示,试验组使用总剂量明显低于对照组,且组间结果比较差异具有统计学意义(P<0.05)。结论本研究提示基于“子母补泻”配穴法针刺五输穴联合阿片类药物的总体临床疗效优于单纯使用阿片类药物,且能一定程度上减少药物用量,具有临床应用价值。

关键词：五输穴针刺胃癌癌痛

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齿轮钢和蓝宝石的低速摩擦特性对比研究

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现代制造工程 2015年第11期 15-19,25页

作者：李子沐姜峰董树尧华侨大学制造工程研究院厦门361021

通过单颗磨粒划擦试验,研究齿轮钢(42Cr Mo V)和蓝宝石(α-Al2O3)的摩擦磨损特性。采集划擦试验过程中的力信号,比较在不同的划痕深度、划痕速度和压头角度条件下,齿轮钢和蓝宝石分别与金刚石压头所形成的摩擦副的摩擦因数μ。结果表明... 详细信息

通过单颗磨粒划擦试验,研究齿轮钢(42Cr Mo V)和蓝宝石(α-Al2O3)的摩擦磨损特性。采集划擦试验过程中的力信号,比较在不同的划痕深度、划痕速度和压头角度条件下,齿轮钢和蓝宝石分别与金刚石压头所形成的摩擦副的摩擦因数μ。结果表明:划痕深度、划痕速度对两种材料与金刚石压头所形成的摩擦副的摩擦因数μ均无影响;压头角度对两种材料与金刚石压头所形成的摩擦副的摩擦因数μ均有影响,且随着压头角度的增大,两种材料与金刚石压头所形成的摩擦副的摩擦因数μ均增大;在相同试验条件下,蓝宝石与金刚石压头所形成的摩擦副的摩擦因数大于齿轮钢与金刚石压头所形成的摩擦副的摩擦因数。

关键词：单颗磨粒齿轮钢蓝宝石摩擦因数

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