检索结果-南通市图书馆

Chemical Activation of S/li2S in li-S Batteries by a Bidirectional Organic Redox Mediator

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2024年第5期40卷 927-934页

作者： li Chengqiu ZHOU Chaoyong MEI Shilin YAO Changjiang State Key Laboratory of Explosion Science and Safety Protection School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing100081P.R.China Xi’an Safty Energy Technology Co. Ltd.Xi’an710299P.R.China

The energy density and lifespan of prototype li-S batteries under high sulfur loading and lean electrolyte have been mainly restricted by the incomplete interconversion between insulating S8 and *** introduction of an electrocatalyst has been preserved as an effective way to breakthrough the bottleneck of the interconversion ***,we demonstrate a novel bidirectional redox mediator,insoluble dithiobisphthalimide(DTPI),as the electrocatalyst for both S8 reduction and li2S *** to the dual-functional role of both electron/li^(+)donor and acceptor,DTPI can efficiently accelerate the redox reactions during charge/discharge and significantly alleviate the incomplete conversion of sulfur ***,the li-S batteries with DTPI deliver superior specific capacity and cycling stability in comparison with those without ***,the redox mediator is scalable for synthesis and the DTPI-based 5 A·h pouch cell delivers a specific discharge capacity of around 870 mA·h·g^(−1) at 0.1 C(1 C=1675 mA/g)without capacity fading over 80 *** bidirectional catalysis mechanism has been studied through theoretical calculation and ex-situ characterization of the cathode *** work approves the effectiveness of bidirectional organic redox mediator in the construction of practical li-S batteries.

关键词： lithium-sulfur battery(LSB) Dithiobisphthalimide(DTPI) Organic redox mediator Interconversion

Semi-automated detection of rangeland runoff and erosion control berms using high-resolution topography data

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Soil and Water Conservation Research 2024年第1期12卷 217-226页

作者： li li Changjiang River Scientific Research Institute of Changjiang Water Resources Commission Wuhan430010China Research Center on Mountain Torrent&Geologic Disaster Prevention Ministry of Water ResourcesWuhan430010China University of Arizona School of Natural Resources and the EnvironmentTucsonAZ85719USA

An inventory of topographic modifications is essential to addressing their impacts on hydrological and morphological processes in human-altered ***,such inventories are generally *** study presents two workflows for semi-automatic detection of linear earthen runoff and erosion control berms in rangelands using high-resolution topographic *** workflows consist of initial object identification by applying either morphological grayscale reconstruction(MGR)or the Geomorphon(GEO)method,followed by identification refinements through filters based on objects’horizontal and vertical *** sites were selected within the Altar Valley,Arizona,in the southwestern United *** site was used for developing workflows and optimizing filter thresholds,and the other two sites were used to validate *** results showed that:1)The MGR-based workflow methodology could produce final precision and detection rates of up to 92%and 75%,respectively,and take less than 5 s for a 10.1 km^(2) site;2)The workflow based on the MGR method yielded greater identification accuracy than did the GEO workflow;3)Object length,orientation,and eccentricity were important characteristics for identifying earthen berms,and are sensitive to general channel flow direction and berm shape;4)Manual interrogation of topographic data and imagery can significantly improve identification precision *** proposed workflows will be useful for developing inventories of runoff and erosion control structures in support of sustainable rangeland management.

关键词： Earthen berm Rangeland Grayscale morphological reconstruction Geomorphon liDAR

Perturbed low-thrust geostationary orbit transfer guidance via polynomial costate estimation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第3期37卷 181-193页

作者： Zhao li Hengnian li Fanghua JIANG Junfeng li State Key Laboratory of Astronautic Dynamics Xi’an Satellite Control CenterXi’an 710043China School of Aerospace Engineering Tsinghua UniversityBeijing 100084China

This paper proposes an optimal,robust,and efficient guidance scheme for the perturbed minimum-time low-thrust transfer toward the geostationary *** Earth’s oblateness perturbation and shadow are taken into *** is difficult for a Lyapunov-based or trajectory-tracking guidance method to possess multiple characteristics at the same time,including high guidance optimality,robustness,and onboard computational *** this work,a concise relationship between the minimum-time transfer problem with orbital averaging and its optimal solution is identified,which reveals that the five averaged initial costates that dominate the optimal thrust direction can be approximately determined by only four initial modified equinoctial orbit elements after a coordinate *** on this relationship,the optimal averaged trajectories constituting the training dataset are randomly generated around a nominal averaged *** polynomial regression models are trained on the training dataset and are regarded as the costate *** the transfer,the spacecraft can obtain the real-time approximate optimal thrust direction by combining the costate estimations provided by the estimators with the current state at any ***,all these computations onboard are *** simulation results show that the proposed guidance scheme possesses extremely high guidance optimality,robustness,and onboard computational efficiency.

关键词： Low thrust Orbital transfer Trajectory optimization Guidance Indirect method Orbital averaging Machine learning Geostationary satellites

Theoretical Analysis of Cooperative Driving at Idealized Unsignalized Intersections

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2024年第1期29卷 257-270页

作者： Shen li Jiawei Zhang Zhenwu Chen li li Department of Civil Engineering Tsinghua UniversityBeijing 100084China Department of Automation Tsinghua UniversityBeijing 100084China Shenzhen Urban Transport Planning Center Co. Ltd.Shenzhen 518000China

Cooperative driving is widely viewed as a promising method to better utilize limited road resources and alleviate traffic *** recent years,several cooperative driving approaches for idealized traffic scenarios(i.e.,uniform vehicle arrivals,lengths,and speeds)have been ***,theoretical analyses and comparisons of these approaches are *** this study,we propose a unified group-by-group zipper-style movement model to describe different approaches synthetically and evaluate their *** derive the maximum throughput for cooperative driving plans of idealized unsignalized intersections and discuss how to minimize the delay of *** obtained conclusions shed light on future cooperative driving studies.

关键词： cooperative driving connected and automated vehicles unsignalized intersection

Effects of mid-passage gap with a variable surface angle on a turbine vane endwall’s aerothermal and film cooling performances

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第6期37卷 20-37页

作者： Zhiyu li Kaiyuan ZHANG Zhigang li Jun li Institute of Turbomachinery Xi’an Jiaotong UniversityXi’an 710049China

The mid-passage gap is an inevitable structure in a vane passage due to turbine vanes being manufactured *** coolant from this gap is able to prevent hot mainstream ingression and provide cooling protection for the endwall.A novel idea of enlarging the endwall’s coverage area and reducing the endwall’s thermal load by applying the mid-passage gap with variable surface angles is carried out in this *** endwall’s aerothermal and film cooling performances under four mid-passage gap modes at three typical mass flow ratio conditions are numerically *** indicate that under the traditional mid-passage mode,the coolant flows into the mainstream with a perpendicular incidence angle and can’t stick to the ***,cooling failure occurs,and the endwall’s thermal load is badly *** film cooling level at the suction-side endwall is improved when applying the mid-passage gap of a 45surface angle due to the secondary vortex being *** addition,when applying the mid-passage gap of a 135surface angle,the horseshoe vortex is pushed away,and the coverage area at the pressure-side endwall is enlarged *** best film cooling performance is achieved when the upstream surface angle is 135and the downstream surface angle is 45due to the adiabatic film cooling effectiveness being increased at both the pressure-and suction-side *** the mass flow ratio is 1.5%,the coverage area is enlarged by 43%,and the area-averaged adiabatic film cooling effectiveness is increased by 37%,when compared with those under the traditional mid-passage mode.

关键词： Film cooling Heat transfer Surface angle Mid-passagegap Turbinevane endwall

在线全文

学校读者我要写书评

暂无评论

射采联作工艺在苏北工区的应用

油气藏评价与开发 2015年第3期5卷 50-52页

作者：张磊李传昌梁珀王波马海粟中国石化华东分公司采油厂江苏泰州225300 中国石化华东分公司工程技术管理处江苏南京210019

针对苏北工区复杂断块油气藏压力系统复杂、强水敏的油藏特点,改进杆式泵、采用延时分级起爆技术以及尾声弹检测技术,成功应用于陈2-2井,形成了苏北工区射采联作工艺。该工艺具有简化现场施工工序、降低修井成本、减少污染等优点,从而... 详细信息

针对苏北工区复杂断块油气藏压力系统复杂、强水敏的油藏特点,改进杆式泵、采用延时分级起爆技术以及尾声弹检测技术,成功应用于陈2-2井,形成了苏北工区射采联作工艺。该工艺具有简化现场施工工序、降低修井成本、减少污染等优点,从而改善开发效果。

关键词：射采联作延时分级起爆技术苏北工区

高吸水性树脂基相变储冷材料及其在冷链运输中的应用

在线全文

学校读者我要写书评

暂无评论

东北电力大学学报 2021年第2期41卷 55-64页

作者：李亚溪林酿志李传常长沙理工大学能源与动力工程学院湖南长沙410114

近年来,冷链运输受到高度重视,冷链运输技术及其相变储冷材料得到了快速发展.本文从高吸水性树脂基相变储冷材料的组成、制备及性能测试进行了综述;总结了高吸水性树脂基相变储冷材料的研究进展及其在农产品冷链运输、血液和疫苗冷链运... 详细信息

近年来,冷链运输受到高度重视,冷链运输技术及其相变储冷材料得到了快速发展.本文从高吸水性树脂基相变储冷材料的组成、制备及性能测试进行了综述;总结了高吸水性树脂基相变储冷材料的研究进展及其在农产品冷链运输、血液和疫苗冷链运输以及海鲜冷链运输中的应用;最后,指出了高吸水性树脂基相变储冷材料的优越性.

关键词：高吸水性树脂相变储冷材料冷链运输

Failure mechanisms and surface treatment processes of thermal barrier coatings:Review

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第9期37卷 20-40页

作者： Hao li Shengqiang YANG Xiuhong li Wenhui li College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan 030024China Shan.xi Province Key Laboratory of Precise Machining Taiyuan University of TechnologyTaiyuan 030024China College of Aeronautics and Astronautics Taiyuan University of TechnologyTaiyuan 030024China

Thermal Barrier Coatings(TBCs)technology is key to improving the service temperature and the productivity of aircraft *** performance and failure life of TBCs are strongly influenced by surface integrity and ***,recognizing failure mechanisms and developing effective surface treatment processes are crucial for further improving the reliability and durability of *** paper explains the primary reasons for TBC failure,emphasizing on how integrity of surface and interface influences interfacial oxidation,high-temperature erosion,and Calcium-Magnesium-Alumina-Silicate(CMAS)***,this paper completely and rigorously evaluates the research status of TBCs surface treatment processes,including the characteristics and effects of various processes,and describes the requirements and goals of pretreatment and *** addition,a potential direction for the development and application of TBCs surface treatment is suggested.

关键词： Thermal BarrierCoatings(TBCs) Failure Surface treatment processes Processing goals Mass finishing

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

泡沫金属复合相变体系导热性能研究及应用

中南大学学报（自然科学版） 2022年第12期53卷 4687-4699页

作者：肖俊兵邹博庄依杰刘臣臻李传常陈荐长沙理工大学能源与动力工程学院湖南长沙410114 广东工业大学环境科学与工程学院广东广州510006 河北工业大学能源与环境工程学院天津300401 可再生能源电力技术湖南省重点实验室湖南长沙410114

相变储热技术具有储热密度大、工作温度波动幅度小、工艺简单成熟等特点,但其使用的相变材料存在导热系数低且易发生泄漏的问题。利用泡沫金属孔隙结构所形成的快速导热通道及其毛细吸附作用,将其与相变材料结合构建泡沫金属复合相变体... 详细信息

相变储热技术具有储热密度大、工作温度波动幅度小、工艺简单成熟等特点,但其使用的相变材料存在导热系数低且易发生泄漏的问题。利用泡沫金属孔隙结构所形成的快速导热通道及其毛细吸附作用,将其与相变材料结合构建泡沫金属复合相变体系,实现快速传递热量,是目前改善相变材料导热性能的重要手段。本文对泡沫金属复合相变体系等效导热系数预测关联式进行简述,对泡沫金属复合相变体系导热性能进行研究,介绍泡沫金属复合相变体系的应用,并对泡沫金属强化相变材料导热性能的研究趋势进行展望。研究结果表明:科学描述孔隙结构类型及特征有助于预测泡沫金属复合相变体系等效导热系数,研究泡沫金属和纳米添加剂相互影响机制可以避免强化导热手段的无效使用,采用激光增材制造技术可以优化设计泡沫金属孔隙结构,可为泡沫金属强化相变材料导热性能的进一步发展与研究提供参考。

关键词：相变储热热传导多孔介质复合材料泡沫金属