检索结果-南通市图书馆

CES Transactions on Electrical Machines and Systems 2024年第2期8卷 227-239页

作者： Yutong Zhu yaohua li Institute of Electrical Engineering Chinese Academy of Sciences University of Chinese Academy of Sciences China Academy of Railway Sciences Corporation limited (Beijing Zongheng Electromechanical Technology Co.Ltd) IEEE

Increasing attention has been paid to the efficiency improvement of the induction traction system of high-speed trains due to the high demand for energy saving. In emergency self-propelled mode, however, the dc-link voltage and the traction power of the motor are significantly reduced, resulting in decreased traction efficiency due to the low load and low speed operations. Aiming to tackle this problem, a novel efficiency improved control method is introduced to the emergency mode of high-speed train traction system in this paper. In the proposed method, a total loss model of induction motor considering the behaviors of both iron and copper loss is established. An improved iterative algorithm with decreased computational burden is then introduced, resulting in a fast solving of the optimal flux reference for loss minimization at each control period. In addition, considering the parameter variation problem due to the low load and low speed operations, a parameter estimation method is integrated to improve the controller's robustness. The effectiveness of the proposed method on efficiency improvement at low voltage and low load conditions is demonstrated by simulated and experimental results.

关键词： Rotors Stators Optimization Torque Iron Mathematical models Resistance

Coordinated Capacitor Voltage Balancing Method for Cascaded H-bridge Inverter with Supercapacitor and DC-DC Stage

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

CES Transactions on Electrical Machines and Systems 2024年第2期8卷 191-201页

作者： Ye Zhang Zixin li Fanqiang Gao Cong Zhao yaohua li Key Laboratory of High Density Electromagnetic Power and Systems (Chinese Academy of Sciences) Institute of Electrical Engineering Chinese Academy of Sciences Haidian District University of Chinese Academy of Sciences Shijingshan District

Cascaded H-bridge inverter(CHBI) with supercapacitors(SCs) and dc-dc stage shows significant promise for medium to high voltage energy storage applications. This paper investigates the voltage balance of capacitors within the CHBI, including both the dc-link capacitors and SCs. Balance control over the dc-link capacitor voltages is realized by the dcdc stage in each submodule(SM), while a hybrid modulation strategy(HMS) is implemented in the H-bridge to balance the SC voltages among the SMs. Meanwhile, the dc-link voltage fluctuations are analyzed under the HMS. A virtual voltage variable is introduced to coordinate the balancing of dc-link capacitor voltages and SC voltages. Compared to the balancing method that solely considers the SC voltages, the presented method reduces the dc-link voltage fluctuations without affecting the voltage balance of SCs. Finally, both simulation and experimental results verify the effectiveness of the presented method.

关键词： Capacitors Voltage control Fluctuations Voltage fluctuations Pulse width modulation Sorting Modulation

Dynamic Measurement of Intracellular pH Based on Bioluminescent Bacteria

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2024年第2期40卷 287-292页

作者： li yaohua WANG Wei State Key Laboratory of Analytical Chemistry for life Science School of Chemistry and Chemical EngineeringChemBIC(Chemistry and Biomedicine Innovation Center)Nanjing UniversityNanjing210023P.R.China

Intracellular pH(pHi)is a fundamental indicator of cellular physiological state,regulating cellular state and function,and has important research values.Although various probes for measuring intracellular pH were available,it is challenging to reflect pHi in real-time and reversible manners.Herein,we developed a whole-cell bioluminescent(BL)probe based on wild type BL bacteria,photobacterium phosphoreum(P.phosphoreum),to determine and image pHi.The dependence of BL intensity of P.phosphoreum on pH values of culture solutions was established.It was found that BL intensity could respond to the change of pH values rapidly and reversibly.We further revealed that P.phosphoreum maintained pH homeostasis in the extracellular pH(pHe)within the range of 5.0–7.0,while intracellular pH homeostasis was destroyed at the alkaline pHe.This method opens up the enormous potential of BL bacteria as an alternative to fluorescence for monitoring and imaging pHi.

关键词： Bioluminescence P.phosphoreum Intracellular pH Cell imaging

In-situ Fluid Phase Variation along the Thermal Maturation Gradient in Shale Petroleum Systems and Its Impact on Well Production Performance

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Earth Science 2023年第4期34卷 985-1001页

作者： Qianyou Wang Wei Yang yaohua li Zhenxue Jiang Ming Wen Rusi Zuo Xin Wang Zixin Xue yaohua Wang State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing 102249China Department of Earth Ocean and Ecological SciencesUniversity of LiverpoolLiverpool L693GPUK Unconventional Oil and Gas Sciences and Technology Institute China University of PetroleumBeijing 102249China Oil and Gas Survey China Geological SurveyBeijing 100083China Now at the Lyell Centre Heriot-Watt UniversityEdinburgh EH144APUK State Key Laboratory of Marine Geology Tongji UniversityShanghai 200092China College of Geosciences China University of PetroleumBeijing 102249China Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring Central South UniversityChangsha 410083China

In-situ fluid phase behavior is important in determining hydrocarbon contents and the multiphase flow through shale reservoirs.The gas-to-oil ratio(GOR) has been recognized as a critical indicator of fluid types.However,little is known about the impact of fluid phase variation across the thermal maturity on shale oil/gas production(e.g.,estimated ultimate recovery,EUR).According to the specific gravity ratio of oil/gas,the producing GOR was converted and normalized into a mass fraction of gas in total hydrocarbons(MGOR) to compare North American shale oil/gas plays with Chinese shale oil and hybrid gas-condensate plays.A correlation between MGOR,the fluid phases,and production data was established to identify five phase stages of flow.MGORvaries systematically with the different production zones,which shows promise in rapidly indicating the well production performance and high production stages of shale oil/gas plays.The hybrid shale gas condensate index,Tmax,and total gas contents were integrated to present the fluid types and maturity of shale gas-condensates,which indicates fluid phase and production variation across thermal evolution.The results offer a unique perspective on the shale oil reservoir producibility based on the impact of GOR on fluid phases and EUR from the dominant global oil/gas plays.

关键词： shale oil shale gas gas condensate fluid phase thermal maturity sweet spots GOR EUR.

Operando monitoring of dendrite formation in lithium metal batteries via ultrasensitive tilted fiber Bragg grating sensors

在线全文

学校读者我要写书评

暂无评论

light(Science & Applications) 2024年第1期13卷 153-166页

作者： Xile Han Hai Zhong Kaiwei li Xiaobin Xue Wen Wu Nan Hu Xihong Lu Jiaqiang Huang Gaozhi Xiao yaohua Mai Tuan Guo Institute of Photonics Technology Jinan UniversityGuangzhou 510632China Institute of New Energy Technology College of Information Science and TechnologyJinan UniversityGuangzhou 510632China Key Laboratory of Bionic Engineering(Ministry of Education) Jilin UniversityChangchun 130022China The Key Lab of Low-Carbon Chemistry&Energy Conservation of Guangdong Province School of ChemistrySun Yat-Sen UniversityGuangzhou 510275China Sustainable Energy and Environment Thrust The Hong Kong University of Science and Technology(Guangzhou)NanshaGuangzhouGuangdong 511400China Advanced Electronics and Photonics Research Centre National Research Council of CanadaOttawa K1A OR6Canada

lithium(li)dendrite growth significantly deteriorates the performance and shortens the operation life of lithium metal batteries.Capturing the intricate dynamics of surface localized and rapid mass transport at the electrolyte–electrode interface of lithium metal is essential for the understanding of the dendrite growth process,and the evaluation of the solutions mitigating the dendrite growth issue.Here we demonstrate an approach based on an ultrasensitive tilted fiber Bragg grating(TFBG)sensor which is inserted close to the electrode surface in a working lithium metal battery,without disturbing its operation.Thanks to the superfine optical resonances of the TFBG,in situ and rapid monitoring of mass transport kinetics and lithium dendrite growth at the nanoscale interface of lithium anodes have been achieved.Reliable correlations between the performance of different natural/artificial solid electrolyte interphases(SEIs)and the time-resolved optical responses have been observed and quantified,enabling us to link the nanoscale ion and SEI behavior with the macroscopic battery performance.This new operando tool will provide additional capabilities for parametrization of the batteries’electrochemistry and help identify the optimal interphases of lithium metal batteries to enhance battery performance and its safety.

关键词： battery lithium electrolyte

考虑评论情感表达力及其重要性的个性化推荐算法

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

数据分析与知识发现 2024年第1期8卷 69-79页

作者：李慧胡耀华徐存真西安电子科技大学经济与管理学院西安710119

【目的】针对数据稀疏性问题,为探索情感表达对用户特征表示的影响,提出一种考虑评论情感表达力及其重要性的个性化推荐算法。【方法】使用BERT预训练语言模型获取评论文本的向量表示,通过Bi-GRU网络学习其中的语义特征,分别采用情感权... 详细信息

【目的】针对数据稀疏性问题,为探索情感表达对用户特征表示的影响,提出一种考虑评论情感表达力及其重要性的个性化推荐算法。【方法】使用BERT预训练语言模型获取评论文本的向量表示,通过Bi-GRU网络学习其中的语义特征,分别采用情感权重和注意力机制为评论向量分配权重,最后利用DeepFM算法对用户特征和产品特征进行深度交互,预测用户对产品的评分值。【结果】在Amazon Product Data数据集上的实验结果表明,所提算法比基线算法在RMSE和MAE指标上最多可降低24.43%和31.44%;使用情感权重为用户评论加权的方法相比于注意力机制,在RMSE与MAE指标上最多可降低2.59%和3.89%。【局限】所用情感分析方法无法表现用户对产品不同属性的情感倾向。【结论】所提算法考虑了情感对用户特征表达的影响,能够提高推荐准确性。

关键词：推荐算法深度学习情感分析注意力机制

The issues on the commercialization of perovskite solar cells

在线全文

学校读者我要写书评

暂无评论

Materials Futures

Materials Futures 2024年第2期3卷 1-35页

作者： lixiu Zhang Yousheng Wang Xiangchuan Meng Jia Zhang Pengfei Wu Min Wang Fengren Cao Chunhao Chen Zhaokui Wang Fu Yang Xiaodong li Yu Zou Xi Jin Yan Jiang Hengyue li Yucheng liu Tongle Bu Buyi Yan Yaowen li Junfeng Fang lixin Xiao Junliang Yang Fuzhi Huang Shengzhong liu Jizhong Yao liangsheng liao liang li Fei Zhang Yiqiang Zhan Yiwang Chen yaohua Mai liming Ding Center for Excellence in Nanoscience(CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication(CAS)National Center for Nanoscience and TechnologyBeijing 100190People’s Republic of China Institute of New Energy Technology College of Information Science and TechnologyJinan UniversityGuangzhou 510632People’s Republic of China Institute of Polymers and Energy Chemistry(IPEC) Nanchang UniversityNanchang 330031People’s Republic of China School of Information Science and Technology Fudan UniversityShanghai 200433People’s Republic of China School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072People’s Republic of China School of Physical Science and Technology Soochow UniversitySuzhou 215006People’s Republic of China Institute of Functional Nano&Soft Materials(FUNSOM) Soochow UniversitySuzhou 215123People’s Republic of China Institute of optoelectronics Fudan UniversityShanghai 200433People’s Republic of China College of Chemistry Chemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123People’s Republic of China School of Physics and Electronic Science East China Normal UniversityShanghai 200241People’s Republic of China State Key Laboratory for Artificial Microstructure and Mesoscopic Physics Department of PhysicsPeking UniversityBeijing 100871People’s Republic of China College of Biophotonics South China Normal UniversityGuangzhou 510631People’s Republic of China School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081People’s Republic of China School of Physics and Electronics Central South UniversityChangsha 410083People’s Republic of China School of Materials Science and Engineering Shaanxi Normal UniversityXi’an 710119People’s Republic of China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070People’s Republic of China Microquanta semiconductor Hangzhou 311121People’s Republic of China

Perovskite solar cells have aroused a worldwide research upsurge in recent years due to their soaring photovoltaic performance,ease of solution processing,and low cost.The power conversion efficiency record is constantly being broken and has recently reached 26.1%in the lab,which is comparable to the established photovoltaic technologies such as crystalline silicon,copper indium gallium selenide and cadmium telluride(CdTe)solar cells.Currently,perovskite solar cells are standing at the entrance of industrialization,where huge opportunities and risks coexist.However,towards commercialization,challenges of up-scaling,stability and lead toxicity still remain,the proper handling of which could potentially lead to the widespread adoption of perovskite solar cells as a low-cost and efficient source of renewable energy.This review gives a holistic analysis of the path towards commercialization for perovskite solar cells.A comprehensive overview of the current state-of-the-art level for perovskite solar cells and modules will be introduced first,with respect to the module efficiency,stability and current status of industrialization.We will then discuss the challenges that get in the way of commercialization and the corresponding strategies to address them,involving the upscaling,the stability and the lead toxicity issue.Insights into the future direction of commercialization of perovskite photovoltaics was also provided,including the flexible perovskite cells and modules and perovskite indoor photovoltaics.Finally,the future perspectives towards commercialization are put forward.

关键词： commercializations perovskite solar cells state-of-the-art level challenges and perspectives indoor photovoltaics

感应电能传输系统多并联拾取模块电流和输出功率均衡方法

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

电力系统自动化 2024年第5期48卷 120-127页

作者：杨继鑫史黎明殷正刚范满义李耀华中国科学院电力电子与电气驱动重点实验室(中国科学院电工研究所) 北京市100190 中国科学院大学北京市100049

大功率感应电能传输系统通常采用多并联拾取模块结构。然而,多并联拾取模块参数不一致,会导致各个拾取模块的电流和输出功率不均衡,从而降低系统效率,严重时会因模块过流而造成系统故障。为解决该问题,文中提出一种基于并联拾取模块补... 详细信息

大功率感应电能传输系统通常采用多并联拾取模块结构。然而,多并联拾取模块参数不一致,会导致各个拾取模块的电流和输出功率不均衡,从而降低系统效率,严重时会因模块过流而造成系统故障。为解决该问题,文中提出一种基于并联拾取模块补偿电容器的多并联拾取模块电流和输出功率均衡方法。首先,介绍了传统感应电能传输系统与所提出的感应电能传输系统拓扑的特性。然后,分别分析了互感、拾取线圈自感及内阻对电流分布和系统效率的影响。最后,通过4个并联拾取模块的感应电能传输系统实验平台验证了所提方法的有效性。实验结果表明,采用所提方法时多并联拾取模块的电流和输出功率基本一致,并且相比传统感应电能传输系统,系统效率最高提升了2.21%。

关键词：感应电能传输系统多并联拾取模块补偿电容器电流均衡输出功率均衡系统效率

经内科胸腔镜肺大疱减容术治疗慢性阻塞性肺疾病合并巨型肺大疱的疗效和安全性研究

在线全文

学校读者我要写书评

暂无评论

四川大学学报（医学版） 2024年第2期55卷 403-410页

作者：路慧李振华余耀华李国燕梁婷婷张华郑州大学郑州450000 郑州大学附属郑州中心医院呼吸与危重症医学科郑州450000

目的探讨经内科胸腔镜肺大疱减容术治疗慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)合并巨型肺大疱(giant emphysematous bulla, GEB)的疗效和安全性。方法选取2021年3月–2022年12月就诊于郑州大学附属郑州中心... 详细信息

目的探讨经内科胸腔镜肺大疱减容术治疗慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)合并巨型肺大疱(giant emphysematous bulla, GEB)的疗效和安全性。方法选取2021年3月–2022年12月就诊于郑州大学附属郑州中心医院的66例COPD合并GEB患者作为研究对象,将患者分为内科胸腔镜组(采用经内科胸腔镜肺大疱减容术治疗)30例和外科胸腔镜组(采用电视辅助胸腔镜手术治疗)36例,所有患者在出院前、出院后3个月、6个月进行随访。比较两组手术前后肺功能、六分钟步行距离(6-minute walk distance, 6MWD)、圣乔治呼吸问卷(St.George's respiratory questionnaire, SGRQ)评分及术后并发症差异,评估手术时长、术后住院时长、手术和住院费用、术后24 h最大视觉模拟评分(visual analog scale, VAS)。结果两组基线资料差异无统计学意义,具有可比性;内科胸腔镜组[(0.78±0.29) L vs.(1.02±0.31) L,P<0.001]和外科胸腔镜组术后6个月第一秒用力呼气容积(forced expiratory volume in 1 second, FEV1)较术前均有改善[(0.80±0.21) L vs.(1.03±0.23) L,P<0.001],两组6MWD、SGRQ评分于术后3个月和术后6个月也观察到一定程度的改善(与术前相比,P<0.05),且于术后随访期间两组患者上述指标的组间比较差异无统计学意义。两组患者手术时间差异无统计学意义,内科胸腔镜组术后住院时间[(7.3±2.6) d]、术后24 hVAS疼痛评分[3.0(2.0, 3.3)分]均低于外科胸腔镜组[(10.4±4.3) d,4.5(3.0, 5.0)分],差异有统计学意义(P<0.05),内科胸腔镜组手术花费和住院总花费低于外科胸腔镜组(P<0.05)。内科胸腔镜组的并发症发生率低于外科胸腔镜组(46.7%vs. 52.8%),但差异无统计学意义。结论经内科胸腔镜肺大疱减容术能改善COPD合并GEB患者的肺功能、生活质量和运动耐力,减轻术后短期疼痛,缩短术后住院时间,具有创伤小、恢复快、花费少的优点,值得临床推广应用。

关键词：慢性阻塞性肺疾病巨型肺大疱胸腔镜手术肺减容术

Study on driver’s braking intention identification based on functional near-infrared spectroscopy

在线全文

学校读者我要写书评

暂无评论

Journal of Intelligent and Connected Vehicles

Journal of Intelligent and Connected Vehicles 2018年第3期1卷 107-113页

作者： Lei Zhu Shuguang li yaohua li Min Wang Yanyu li Jin Yao School of Manufacturing Science and Engineering Sichuan UniversityChengduChina Department of Neurology Chengdu City First People’s HospitalChengduChina Sichuan University ChengduChina

Purpose–Cooperative driving refers to a notion that intelligent system sharing controlling with human driver and completing driving task together.One of the key technologies is that the intelligent system can identify the driver’s driving intention in real time to implement consistent driving decisions.The purpose of this study is to establish a driver intention prediction model.Design/methodology/approach–The authors used the NIRx device to measure the cerebral cortex activities for identifying the driver’s braking intention.The experiment was carried out in a virtual reality environment.During the experiment,the driving simulator recorded the driving data and the functional near-infrared spectroscopy(fNIRS)device recorded the changes in hemoglobin concentration in the cerebral cortex.After the experiment,the driver’s braking intention identification model was established through the principal component analysis and back propagation neural network.Findings–The research results showed that the accuracy of the model established in this paper was 80.39 per cent.And,the model could identify the driver’s braking intent prior to his braking operation.Research limitations/implications–The limitation of this study was that the experimental environment was ideal and did not consider the surrounding traffic.At the same time,other actions of the driver were not taken into account when establishing the braking intention recognition model.Besides,the verification results obtained in this paper could only reflect the results of a few drivers’identification of braking intention.Practical implications–This study can be used as a reference for future research on driving intention through fNIRS,and it also has a positive effect on the research of brain-controlled driving.At the same time,it has developed new frontiers for intention recognition of cooperative driving.Social implications–This study explores new directions for future brain-controlled driving and wheelchairs.Originality/value–The driver’s driving intention was predic

关键词： Machine learning fNIRS Cooperative driving Driving intention identification