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一种散热器的性能衰减实验研究

工程热物理学报 2024年第4期45卷 1162-1168页

作者：纳鑫郭鈺乾侯博卢鑫王良璧兰州交通大学机电工程学院兰州730070 铁道车辆热工教育部重点实验室(兰州交通大学) 兰州730070

内燃机车散热器是内燃机车冷却系统的核心组成部分,随着运行里程增加,翅片表面表面积灰,散热器管内沉积污垢,或由于腐蚀冲蚀等,部分管子破损后堵管。如此一系列的累计作用,导致散热热阻增大,空气侧、水侧流动阻力增加,严重降低散热器的... 详细信息

内燃机车散热器是内燃机车冷却系统的核心组成部分,随着运行里程增加,翅片表面表面积灰,散热器管内沉积污垢,或由于腐蚀冲蚀等,部分管子破损后堵管。如此一系列的累计作用,导致散热热阻增大,空气侧、水侧流动阻力增加,严重降低散热器的性能,最终不能满足内燃机车柴油机的工作要求。为了给运用管理部门提供做出多长时间大修或更换散热器决策依据,需要散热器性能衰减规律。为此,论文通过对运行里程达到90、180万公里HXN5型内燃机车上拆检的散热器进行传热性能实验,获得该部件经90、180万公里后的实际性能状态。在额定运行工况(额定水流量及空气质量流速为10.3 kg·m^(-2)·s^(-1)时),相较于全新HXN5型内燃机车散热器,运行90万公里后主散热器传热系数下降了22.96%,运行180万公里后主散热器传热系数下降27.93%。另外,根据不同堵管率的实验结果表明堵管为散热器性能衰减的次要因素,主要因素是翅片表面及管内壁的污垢热阻。

关键词： HXN5型内燃机车散热器实验研究传热性能

Quantitative and Qualitative Responses of Hydroponic Tomato Production to Different Levels of Salinity

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Phyton-International Journal of Experimental Botany 2024年第6期93卷 1311-1323页

作者： Khalid A.Al-Gaadi Ahmed m.Zeyada ElKamil Tola Abdullah m.Alhamdan Khalid A.m.Ahmed Rangaswamy madugundu mohamed K.Edrris Department of Agricultural Engineering College of Food and Agriculture SciencesKing Saud UniversityRiyadh11451Saudi Arabia Precision Agriculture Research Chair Deanship of Scientific ResearchKing Saud UniversityRiyadh11451Saudi Arabia Chair of Dates Industry&Technology Deanship of Scientific ResearchKing Saud UniversityRiyadh11451Saudi Arabia Agricultural Research Centre Agricultural Engineering Research Institute(AEnRI)Giza12619Egypt

From economic and nutritional points of view,tomato is,historically,considered one of the most important *** signiﬁcant yield reduction,most commercial cultivars of tomato crops are sensitive to moderate levels of ***,high levels of salt stress can negatively affect the yield and quality of tomato ***,this study was conducted to evaluate the yield and fruit quality of three tomato cultivars(Forester,Ghandowra-F1,and Feisty-Red)cultivated hydroponically,under three different levels of nutrient solution *** of tomato fruits was performed based on quantity(number and weight of fruits,and total fruit yield),physical quality(color andﬁrmness),and chemical quality(refractometric index“Brix”,pH,EC,K^(+),na^(+),and NO_(3)-).Experiments were conducted using three salinity levels of the nutrient solution with electrical conductivity values(dSm^(-1))of 2.5(control),6.0,and *** showed that the studied tomato cultivars were signiﬁcantly inﬂuenced by high salinity(9.5 dSm^(-1))in comparison to the low(2.5 dSm^(-1))and medium(6.0 dSm^(-1))levels of *** average,the highest fruit weight per plant of 1944.84 g and total fruit yield of 4.42 kgm^(-2) were observed at the low salinity level;however,no signiﬁcant differences were obtained in the two yield factors(single fruit weight and total fruit yield)for the low and medium salinity *** the other hand,a signiﬁcant reduction in tomato yield(31%)was associated with the high salinity level compared to the yield at low and medium salinity *** of physical quality parameters showed highly signiﬁcant differences among all salinity *** average,the maximum value of color change(1.72)was associated with the medium salinity level,and the maximum value ofﬁrmness(9.61 Ncm^(-1))was recorded at the high salinity *** levels and tomato cultivars introduced signiﬁcant differences in chemical quality parameters;however,no signiﬁcant differences in these

关键词： Quality cultivars yield color ﬁrmness brix

In vivo and in vitro study of resorbable magnesium wires for medical implants:mg purity,surface quality,Zn alloying and polymer coating

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Journal of magnesium and Alloys 2024年第6期12卷 2472-2488页

作者： K.Tesar J.Luňácková m.Jex m.Žaloudková R.Vrbová m.Bartoš P.Klein L.Vištejnová J.Dušková E.Filová Z.Sucharda m.Steinerová S.Habr K.Balík A.Singh Department of materials Faculty of Nuclear Sciences and Physical EngineeringCzech Technical University in PragueTrojanova 13Prague 12000Czech Republic Institute of Physics Czech Academy of SciencesNa Slovance 2Prague 18221Czech Republic Institute of Dental medicine First Faculty of MedicineCharles University and General University Hospital in PragueKaterinská32Prague 12801Czech Republic Department of Physics Faculty of Nuclear Sciences and Physical EngineeringCzech Technical University in PragueBrehová7Prague 11519Czech Republic Department of Composites and Carbon materials Institute of Rock Structure and MechanicsCzech Academy of SciencesV Holešovickách 41Prague 18209Czech Republic Institute of Anatomy First Faculty of MedicineCharles UniversityU Nemocnice 3Prague 12800Czech Republic Biomedical Center Faculty of Medicine in PilsenCharles UniversityAlej Svobody 76Pilsen 32300Czech Republic Department of Pathological Physiology Faculty of Medicine in PilsenCharles UniversityAlej Svobody 7632300 PilsenCzech Republic Department of Histology and Embryology Faculty of Medicine in PilsenCharles UniversityAlej Svobody 7632300 PilsenCzech Republic Institute of Pathology First Faculty of MedicineCharles University and General University Hospital in PragueStudnickova 2Prague 12800Czech Republic Department of Biomaterials and Tissue Engineering Institute of PhysiologyCzech Academy of SciencesVidenska 1083Prague 14200Czech Republic Research Center for Structural materials National Institute for Materials Science1-2-1 SengenTsukuba 305-0047Japan

magnesium is an excellent material in terms of biocompatibility and its corrosion products can serve as an active source for new bone ***,localized corrosion and H_(2)generation limit the potential of mg-based *** low-alloyed mg-Zn wires can strongly reduce problems with large H_(2)bubbles and improve the mechanical properties considerably while maintaining excellent long-term *** pickling and a polymer coating can be effectively used to lower the rate of in vivo *** this work,microstructural,mechanical,and in vitro characterization of 250μm and 300μm extruded wires made from ultra-pure mg,commercially pure mg,mg-0.15Zn,mg-0.4Zn and mg-1Zn was ***,mg-0.4Zn wires together with a variant coated with a copolymer of L-lactide andε-caprolactone were tested in vivo on artificially damaged Wistar rat *** on the observed mg-induced osteogenesis,polymer-coated mg wires with a small addition of Zn are a perspective material for bone-support applications,such as cerclage and fixation wires.

关键词： magnesium Resorbable mg wire mg-Zn implant degradation Biocompatibility study Zn grain boundary segregation

基于时空优化模型的Pm_(2.5)遥感估测研究

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中国环境科学 2024年第7期44卷 3625-3636页

作者：张娜陈文倩白雪松曹肖奕青岛理工大学信息与控制学院山东青岛266520 兰州大学大气科学学院半干旱气候变化教育部重点实验室甘肃兰州730000

为了获得连续的Pm_(2.5)浓度时空分布并提高估算精度,提出了一种新的基于时空因子优化的Pm_(2.5)估测模型(SFRF).SFRF模型是时空因子通过卷积特征融合到随机森林算法(RF)体系中,通过集成高分辨率(1km)卫星反演的气溶胶光学厚度(AOD)产... 详细信息

为了获得连续的Pm_(2.5)浓度时空分布并提高估算精度,提出了一种新的基于时空因子优化的Pm_(2.5)估测模型(SFRF).SFRF模型是时空因子通过卷积特征融合到随机森林算法(RF)体系中,通过集成高分辨率(1km)卫星反演的气溶胶光学厚度(AOD)产品以及气象数据、夜间灯光数据和植被数据构建SFRF模型来进行对2019年的山东省地区Pm_(2.5)浓度的准确预测,生成山东省高空间分辨率(1km)的Pm_(2.5)浓度.采用十折交叉验证法,评估了SFRF模型的性能,并与BPNN、SVm、XGBoost、RF、PCA-RF模型进行对比.结果表明:SFRF模型验证的决定系数和均方根误差(RmSE)值分别为0.85和8.10µg/m^(3),优于其他模型.SFRF模型可以在日、季、年尺度上以较高的空间分辨率来估测山东省Pm_(2.5)浓度.

关键词： Pm_(2.5) 时空优化模型 AOD 山东省地区

Europium recovery process by means of polymeric nanoparticles functionalized with acrylic acid,curcumin and fumaramide

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Journal of Rare Earths 2024年第10期42卷 1950-1959页

作者： P.A.martínez-montoya J.m.del Río A.de J.morales-Ramirez m.Corea Escuela Superior de Ingeniería Química e Industrias Extractivas ESIQIE-IPNDepartamento de Ingeniería Metalúrgica UPALM S/N Col.Lindavista Escuela Superior de Ingenieria Química e Industrias Extractivas ESIQIE-IPNLaboratorio de Investigación en Polímeros y NanomaterialesUPALM S/N Col.Lindavista Centra de Investigación e Innovación Tecnológica CIITEC-IPNCda.de CECATIs/n

polymeric nanoparticles of poly(methyl methacrylate) were obtained by emulsion polymerization techniques in a proce ss of two *** particles were functionalized with acrylic acid,curcumin,and fumaramide and three series of polymeric particles were *** incorporation of functional groups was confirmed by Fourier transform-infrared spectrosocopy(FT-IR) and ultraviolet-visible(UV-Vis) *** spherical morphology of particles with an average diameter of 100 nm was observed by scartning electron microscopy(SEm).The polymeric materials were used for recovery of [Eu]from synthetic *** nanoparticles show excellent chelation capacity to trap rare-earth ions,because they recover more than 85% of [Eu] at pH of *** images of SEm after extraction process show arrays between particles with larger average particle sizes to 1.5 *** addition,the particles have a good stripping capacity,exceeding 50% of it,maintaining their homogeneity in morphology and good stability in dispersion for the recovery and stripping processes.A pseudo-second model order is obtained for the extraction and stripping processes while the best results of stripping process are obtained at pH of6.

关键词： [Eu] recovery Chelating effect Extraction process Stripping process Emulsion polymerization Rare earths

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储能的低温空气分离系统热力学与经济性分析

西安交通大学学报 2024年第9期58卷 1-10页

作者：秦晓巧谭宏博温娜刘伟明西安交通大学制冷与低温工程系西安710049 陕西鼓风机(集团)有限公司西安710082

为探索低温空气分离系统(ASU)进行电力需求错峰运行的可行性,将传统空气分离技术与液态空气储能技术(LAES)结合,在谷电期先将富余空气压缩、液化、储存,在峰电期将液态空气作为精馏原料补充到精馏塔,以提高谷时压缩用电负荷、降低峰时... 详细信息

为探索低温空气分离系统(ASU)进行电力需求错峰运行的可行性,将传统空气分离技术与液态空气储能技术(LAES)结合,在谷电期先将富余空气压缩、液化、储存,在峰电期将液态空气作为精馏原料补充到精馏塔,以提高谷时压缩用电负荷、降低峰时压缩用电负荷。与传统空气分离系统相比,氧气产品的标准状态体积流量为10165m^(3)/h的低温空气分离储能系统(ASU-LAES)可将压缩能耗的20%由电网高峰时段转移到低谷时段,年度用电成本可减少1.3%~6.8%。ASU-LAES系统的制氧单位压缩能耗为0.349kW·h/m^(3),设备投资成本为4034.8万元,动态回收期为4.6~5.2a。ASU-LAES方案可缓解电网高峰负荷用电压力,充分利用峰谷分时电价政策优势,可创造良好的经济效益。

关键词：空气分离液态空气储能设备投资动态回收期

Targeting cAmP in D1-mSNs in the nucleus accumbens, a new rapid antidepressant strategy

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Acta Pharmaceutica Sinica B 2024年第2期14卷 667-681页

作者： Yue Zhang Jingwen Gao na Li Peng Xu Shimeng Qu Jinqian Cheng mingrui Wang Xueru Li Yaheng Song Fan Xiao Xinyu Yang Jihong Liu Hao Hong Ronghao mu Xiaotian Li Youmei Wang Hui Xu Yuan Xie Tianming Gao Guangji Wang Jiye Aa Jiangsu Provincial Key Laboratory of Drug metabolism and Pharmacokinetics State Key Laboratory of Natural MedicinesResearch Unit of PK-PD Based Bioactive Components and Pharmacodynamic Target Discovery of Natural Medicine of Chinese Academy of Medical SciencesChina Pharmaceutical UniversityNanjing 210009China Key Laboratory of Drug monitoring and Control Drug Intelligence and Forensic CenterMinistry of Public SecurityBeijing 100193China School of Pharmacy China Pharmaceutical UniversityNanjing 211198China School of Foreign Languages China Pharmaceutical UniversityNanjing 211198China Department of Neurobiology School of Basic Medical SciencesSouthern Medical UniversityGuangzhou 510515China Department of Pharmacology China Pharmaceutical UniversityNanjing 211198China School of Pharmaceutical Sciences Zhengzhou UniversityZhengzhou 450001China

Studies have suggested that the nucleus accumbens(nac)is implicated in the pathophysiology of major depression;however,the regulatory strategy that targets the nac to achieve an exclusive and outstanding anti-depression benefit has not been ***,we identified a specific reduction of cyclic adenosine monophosphate(cAmP)in the subset of dopamine D1 receptor medium spiny neurons(D1-mSNs)in the nac that promoted stress susceptibility,while the stimulation of cAmP production in nac D1-mSNs efficiently rescued depression-like *** treatment enhanced cAmP both in D1-mSNs and dopamine D2 receptor medium spiny neurons(D2-mSNs)of depressed mice,however,the rapid antidepressant effect of ketamine solely depended on elevating cAmP in nac *** discovered that a higher dose of crocin markedly increased cAmP in the nac and consistently relieved depression 24 h after oral administration,but not a lower *** fast onset property of crocin was verified through multicenter ***,crocin specifically targeted at D1-mSN cAmP signaling in the nac to relieve depression and had no effect on *** findings characterize a new strategy to achieve an exclusive and outstanding anti-depression benefit by elevating cAmP in D1-mSNs in the nac,and provide a potential rapid antidepressant drug candidate,crocin.

关键词： CAmP Nucleus accumbens Depression D1-mSN D2-mSN

Comparison between solid pseudopapillary neoplasms of the pancreas and pancreatic ductal adenocarcinoma with cystic changes using computed tomography

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World Journal of Radiology 2024年第6期16卷 211-220页

作者： Shuai Ren Li-Chao Qian Xiao-Jing Lv Ying-Ying Cao marcus J Daniels Zhong-Qiu Wang Li-na Song Ying Tian Department of Radiology Jiangsu Province Hospital of Chinese MedicineThe Affiliated Hospital of Nanjing University of Chinese MedicineNanjing 210029Jiangsu ProvinceChina Department of Geratology Nanjing Hospital of Chinese Medicine Affiliated to Nanjing University of Chinese MedicineNanjing 210022Jiangsu ProvinceChina Department of Radiology NYU Langone HealthNew YorkNY 10016United States

BACKGROUND Solid pseudopapillary neoplasms of the pancreas(SPN)share similar imaging findings with pancreatic ductal adenocarcinoma with cystic changes(PDAC with cystic changes),which may result in unnecessary *** To investigate the value of computed tomography(CT)in differentiation of SPN from PDAC with cystic *** This study retrospectively analyzed the clinical and imaging findings of 32 patients diagnosed with SPN and 14 patients diagnosed with PDAC exhibiting cystic changes,confirmed through pathological *** and qualitative analysis was performed,including assessment of age,sex,tumor size,shape,margin,density,enhancement pattern,CT values of tumors,CT contrast enhancement ratios,“floating cloud sign,”calcification,main pancreatic duct dilatation,pancreatic atrophy,and peripancreatic invasion or distal *** logistic regression analysis was used to identify relevant features to differentiate between SPN and PDAC with cystic changes,and receiver operating characteristic curves were obtained to evaluate the diagnostic performance of each variable and their *** When compared to PDAC with cystic changes,SPN had a lower age(32 years vs 64 years,Pm vs 3.90 cm,Pmetastasis than PDAC with cystic changes(both Pmor location,shape,margin,density,main pancreatic duct dilatation,calcification,pancreatic atrophy,enhancement pattern,CT values of tumors,or CT contrast enhancement ratios between the two groups(all P>0.05).The area under the receiver operating characteristic curve of the combination was 0.833(95%confidence interval:0.708-0.957)with 78.6%sensitivity,81.3%specificity,and 80.4%accuracy in differentiation of SPN from PDAC with cystic *** A larger tumor size,“floating cloud sign,”and peri

关键词： Solid pseudopapillary neoplasm Pancreas Pancreatic ductal adenocarcinoma Computed tomography Differential diagnosis

强吸波催化剂协同微波能强化果糖脱水制5-羟甲基糠醛

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化工学报 2024年第4期75卷 1565-1577页

作者：徐安冉刘凯王娜赵振宇李洪高鑫天津大学化工学院精馏技术国家工程研究中心天津300072 物质绿色创造与制造海河实验室天津300192

利用硬模板法制备了中空多孔碳球(mHCS),系统研究了热处理温度、金属负载量、刻蚀前后对mHCS电磁参数的影响。从中选取高介电损耗值(ε″)的mHCS-800(ε″=213)作为催化剂载体,并以SCS-800(ε″=50)和SCS(ε″=0.08)作为对比样品,经磺... 详细信息

利用硬模板法制备了中空多孔碳球(mHCS),系统研究了热处理温度、金属负载量、刻蚀前后对mHCS电磁参数的影响。从中选取高介电损耗值(ε″)的mHCS-800(ε″=213)作为催化剂载体,并以SCS-800(ε″=50)和SCS(ε″=0.08)作为对比样品,经磺化后用于催化果糖水解制5-羟甲基糠醛,根据在微波加热和常规油浴条件下的反应动力学探究了ε″对微波催化效果的影响。结果表明,在80 W微波功率辐照下使用mHCS-800-SO_(3)H作为催化剂,5 min转化率即可达97.7%;反应速率常数(k)为0.76 min^(-1),是常规加热(k=0.0847 min^(-1))的8.97倍,该催化剂相较于SCS-800-SO_(3)H和SCS-SO_(3)H的微波催化效果(k比常规分别提升了164.9%、11.9%)更加显著。以上研究结果源于中空多孔结构和高的石墨化程度相耦合更有利于在催化剂颗粒表面形成“热点”,从而加速催化反应。

关键词：微波辐照果糖水解多相反应动力学介电损耗催化

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