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Dynamic modeling and simulation test of a 60 kW PEMFC generation system

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第6期12卷 475-482页

作者： ying-ying ZHANG Ji-chang SUN ying ZHANG Xi LI Ouang-yi CAO Shandong Provincial Key Laboratory of Ocean Environment Monitoring Technology Shandong Academy of Sciences Institute of Oceanographic Instrumentation Qingdao 266001 China Control Science and Engineering Department Key Laboratory of Education Ministry for Image Processing and lntelligent Control Huazhong University of Science & Technology Wuhan 430074 China Fuel Cell Institute Department of Automation Shanghai Jiao Tong University Shanghai 200030 China

In this paper,a 60 kW proton exchange membrane fuel cell(PEMFC) generation system is modeled in order to design the system parameters and investigate the static and dynamic characteristics for control *** achieve an overall system model,the system is divided into five modules:the PEMFC stack(anode and cathode flows,membrane hydration,and stack voltage and power),cathode air supply(air compressor,supply manifold,cooler,and humidifier),anode fuel supply(hydrogen valve and humidifier),cathode exhaust exit(exit manifold and water return),and power conditioning(DC/DC and DC/AC) *** a combination of empirical and physical modeling techniques,the model is developed to set the operation conditions of current,temperature,and cathode and anode gas flows and pressures,which have major impacts on system *** current model is based on a 60 kW PEMFC power plant designed for residential applications and takes account of the electrochemical and thermal aspects of chemical reactions within the stack as well as flows of reactants across the *** simulation tests show that the system model can represent the static and dynamic characteristics of a 60 kW PEMFC generation system,which is mathematically simple for system parameters and control designs.

关键词： Proton exchange membrane fuel cell(PEMFC) Generation system Dynamic simulation model Reactant flow

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Hepatocellular carcinoma-derived exosomal miRNA-761 regulates the tumor microenvironment by targeting the SOCS2/JAK2/STAT3 pathway

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World Journal of Emergency Medicine 2022年第5期13卷 379-385页

作者： Xiao-hu Zhou Hao Xu chang Xu ying-cai Yan lin-shi Zhang Qiang Sun Wei-lin Wang Yan-jun Shi Department of Hepatobiliary and Pancreatic Surgery the Second Affi liated Hospital of Zhejiang University School of MedicineHangzhou 310009China Key Laboratory of Precision Diagnosis and Treatment for Hepatobiliary and Pancreatic Tumor of Zhejiang Province the Second Affi liated Hospital of Zhejiang University School of MedicineHangzhou 310009China

BACKGROUND:Exosomes and exosomal microRNAs have been implicated in tumor occurrence and *** previous study showed that microRNA-761(miR-761)is overexpressed in hepatocellular carcinoma(HCC)tissues and that its inhibition affects mitochondrial function and inhibits HCC *** mechanism by which exosomal miR-761 modulates the tumor microenvironment has not been ***:Exosomal miR-761 was detected in six cell *** counting kit-8(CCK-8)and transwell migration assays were performed to determine the function of exosomal miR-761 in HCC *** luciferase reporter assay was used to analyze miR-761 target genes in normal fi broblasts(NFs).The inhibitors AZD1480 and C188-9 were employed to determine the role of the Janus kinase 2/signal transducer and activator of transcription 3(JAK2/STAT3)signaling pathway in the transformation of cancer-associated fi broblasts(CAFs).RESULTS:In this study,we characterized the mechanism by which miR-761 reprogrammed the tumor *** found that HCC-derived exosomal miR-761 was taken up by ***,HCC exosomes aff ected the tumor microenvironment by activating NFs via suppressor of cytokine signaling 2(SOCS2)and the JAK2/STAT3 signaling ***:These results demonstrated that exosomal miR-761 modulated the tumor microenvironment via SOCS2/JAK2/STAT3 pathway-dependent activation of *** fi ndings may inspire new strategies for HCC prevention and therapy.

关键词： Exosomes Janus kinase 2/signal transducer and activator of transcription 3(JAK2/STAT3)signaling pathway microRNA-761 Suppressor of cytokine signaling 2 Tumor microenvironment

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Efficient complementary caching for ISP-aware networks

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The Journal of China Universities of Posts and Telecommunications 2012年第5期19卷 66-76页

作者： AO Nai-xiang XU ying-ying CHEN chang-jia School of Electronic Information Engineering Beijing Jiaotong UniversityBeijing 100044China

Internet service providers （ISPs） have taken some measures to reduce intolerable inter-lSP peer-to-peer （P2P） traffic costs, therefore user experiences of various P2P applications have been affected. The recently emerging offiine downloading service seeks to improve user experience by using dedicate servers to cache requested files and provide high-speed uploading. However, with rapid increase in user population, the server-side bandwidth resource of offline downloading system is expected to be insufficient in the near future. We propose a novel complementary caching scheme with the goal of mitigating inter-ISP traffic, alleviating the load on servers of Internet applications and enhancing user experience. Both architecture and caching algorithm are presented in this paper. On the one hand, with full knowledge of P2P file sharing system and offiine downloading service, the infrastructure of complementary caching is designed to conveniently be deployed and work together with existing platforms. The co-operational mechanisms among different major components are also included. On the other hand, with in-depth understanding of traffic characteristics that are relevant to caching, we develop complementary caching algorithm with respect to the density of requests, the redundancy of file and file size. Since such relevant information can be real-time captured in our design, the proposed policy can be implemented to guide the storage and replacement of caching unities, Based on real-world traces over 3 months, we demonstrate that the complementary caching scheme is capable to achieve the ＇three-win＇ objective. That is, for l＇2P downloading, over 50% of traffic is redirected to cache; for offline downloading, the average server-dependence of tasks drops from 0.71 to 0.32; for user experience, the average P2P transfer rate is increased by more than 50 KB/s.

关键词： caching inter-ISP traffic server-side load user experience

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Storage capacity model for cloud download

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The Journal of China Universities of Posts and Telecommunications 2012年第5期19卷 83-91页

作者： XU ying-ying AO Nai-xiang CHEN chang-jia School of Electronics and Information Engineering Beijing Jiaotong UniversityBeijing 100044China

With the rise and world wide deployment of cloud utilities, the principle of the cloud download is proposed to provide high-quality file content distribution by using dedicated servers as cloud cache to guarantee the data availability and enhance the data transfer rate. As the system scales up to a large population, how to design appropriate storage capacity of cloud cache is a key challenge for cloud download. In this paper, primary elements impacting on storage capacity are explored through deliberating in large-scale commercial cloud download system, i.e. general user usage pattern and available period. And based on statistical analysis of real-world traces, we formulate storage capacity related to these two elements, which is the original contribution different from all previous works. This model gives guidance of potential system policy design. Finally, the effectivity of this model is demonstrated by simulation results compared with empirical data of practical system.

关键词： cloud download storage capacity model available period usage pattern

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GAGMS: a requirement-driven general address generation and management system

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Science China(Information Sciences) 2018年第9期61卷 126-140页

作者： ying LIU lin HE Gang REN Institute for Network Sciences and Cyberspace Tsinghua University Tsinghua National Laboratory for Information Science and Technology

IPv6 address generation is closely related to the manageability, security, privacy protection, and traceability of the Internet. There are many kinds of IPv6 address generation and configuration methods in the area of Internet standards and research that may cause certain problems, including the mixed operation problem of multiple IPv6 address generation schemes, the synchronization problem of the change in IPv6 address, the efficiency problem of processing large-scale concurrent IPv6 address requests, and the general model problem for mapping IPv6 addresses to other requirement spaces as identifiers. In this paper, we consider generating and managing IPv6 addresses according to network requirements. After conducting a requirement analysis of most proposed address generation schemes, we propose a general address generation model and a general address management system, which are the cores of the general address generation and management system(GAGMS). This system solves the above problems under the premise of maintaining the diversity and flexibility of the existing IPv6 address generation and configuration methods and allows networks to utilize different address generation schemes according to different requirements in different scenarios. Finally, we design a prototype system and evaluate our GAGMS to demonstrate its effectiveness,manageability, and scalability, and we have conducted trial deployment in campus networks and are trying to standardize this work in IETF.

关键词： IPv6 address generation IPv6 address management requirement analysis DHCPv6 SLAAC

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Impacts of the COVID-19 pandemic on vegetable production and countermeasures from an agricultural insurance perspective

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Journal of Integrative Agriculture 2020年第12期19卷 2866-2876页

作者： GU Hai-ying WANG chang-wei Antai College of Economics and Management Shanghai Jiao Tong UniversityShanghai 200030P.R.China Institute of Industry Research Shanghai Jiao Tong UniversityShanghai 200030P.R.China Institute of Finance and Economics Shanghai University of Finance and EconomicsShanghai 200433P.R.China

In the face of the corona virus disease 2019(COVID-19)pandemic,it is essential to stabilize the security of urban“shopping baskets”.Through a survey and interviews with 46 agricultural cooperatives in Shanghai,this paper analyzes the impact of the pandemic on vegetable production and offers suggestions on agricultural *** research results show that:(1)the pandemic has impacted almost all stages of the vegetable supply chain but has had a greater impact on the sales stage;(2)the market risks of vegetable production have increased significantly,and the gap between the field price and the market price has *** sales price difference between traditional channels and e-commerce is notable;(3)farmers’incomes have generally declined due to the COVID-19 pandemic,and traditional small-scale farmers have suffered more losses;and(4)agricultural insurance plays an important role in stabilizing the supply of vegetables to the *** minimize the impact of the pandemic on vegetable production and to stabilize both urban“shopping baskets”and farmers’incomes,it is necessary to further improve agricultural insurance,especially to provide insurance against market risks.

关键词： COVID-19 vegetable supply chain agricultural insurance market risks

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Structure, Infrared Radiation Properties and Mssbauer Spectroscopic Investigations of Co_(0.6)Zn_(0.4)Ni_xFe_(2-x)O_4 Ceramics

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Journal of Materials Science & Technology 2010年第8期26卷 687-692页

作者： ying Zhang Jun lin Dijiang Wen Inorganic Materials Department College of Chemistry Chemical Engineering and Materials Science Soochow University Suzhou 215123 China Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China

Ferrite compound Co0.6Zn0.4NixFe2-xO4 was synthesized by solid state reaction. The structure and performance of Co0.6Zn0.4NixFe2-xO4 compounds were studied by Moessbauer spectroscopy, X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and infrared radiant tester. Moessbauer spectroscopy and XPS analysis show the valence states and distribution of cations in Co0.6Zn0.4NixFe2-xO4. Zn2＋ has invariably shown preference for the tetrahedral sites, and Ni2＋ has the preference for the octahedral sites. The occupancy of Fe3＋ linearly increases on the tetrahedral sites, and sharply decreases on the octahedral sites with increasing x, owing to its gradual replacement by Ni2＋ on the octahedral sites. It indicates that due to the occupation of octahedral sites by the majority of Ni2＋, Fe3＋ decreasingly migrated from the octahedral sites to the tetrahedral sites and substituted Co3＋ sites, which made the number of Co3＋ in the tetrahedral sites decreasing. According to the measurement results of XRD and the infrared radiant tester analysis, the lattice parameter and infrared radiance have shown a nonlinear variation, exhibiting the infrared average radiance of 0.92 in the 8-14μm waveband, and the results demonstrate that these Co-Zn-Ni spinel ferrites have potential for application in a wide range of infrared heating and drying materials.

关键词： Infrared radiance Moessbauer spectroscopy NiO Spinel ferrites

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Limited Social Support,but Comparable Health Literacy and Service Utilization,Among Elderly People Living Alone—Six PLADs,China,May-September 2020

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China CDC weekly 2024年第39期6卷 1011-1016页

作者： Hao lin Meijun Chen Yuhui Shi ying Ji Yuting lin Wangnan Cao Chun chang Department of Social Medicine and Health Education School of Public HealthPeking University Health Science CenterBeijingChina Center for Healthy Aging Peking University Health Science CenterBeijingChina School of Public Health The University of Hong KongHong Kong Special Administrative RegionChina

What is already known about this topic?The proportion of elderly living alone in China is approximately 10%.Living away from family poses enormous challenges for older *** is added by this report?Compared to those living with family,elderly individuals living alone exhibit a lower registration rate with general practitioners and have less social *** are the implications for public health practice?While the current health service system for elderly people living alone is working relatively well,there is a need for additional programs to enhance social support and improve their social well-being.

关键词： alone elderly service

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Uplink NOMA signal transmission with convolutional neural networks approach

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Journal of Systems Engineering and Electronics 2020年第5期31卷 890-898页

作者： lin Chuan chang Qing LI Xianxu School of Electronic and Information Engineering Beihang UniversityBeijing 100191China State Grid Information and Telecommunication Branch Beijing 100761China

Non-orthogonal multiple access(NOMA), featuring high spectrum efficiency, massive connectivity and low latency, holds immense potential to be a novel multi-access technique in fifth-generation(5G) communication. Successive interference cancellation(SIC) is proved to be an effective method to detect the NOMA signal by ordering the power of received signals and then decoding them. However, the error accumulation effect referred to as error propagation is an inevitable problem. In this paper,we propose a convolutional neural networks(CNNs) approach to restore the desired signal impaired by the multiple input multiple output(MIMO) channel. Especially in the uplink NOMA scenario,the proposed method can decode multiple users' information in a cluster instantaneously without any traditional communication signal processing steps. Simulation experiments are conducted in the Rayleigh channel and the results demonstrate that the error performance of the proposed learning system outperforms that of the classic SIC detection. Consequently, deep learning has disruptive potential to replace the conventional signal detection method.

关键词： non-orthogonal multiple access(NOMA) deep learning(DL) convolutional neural networks(CNNs) signal detection

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Radio map updated method based on subscriber locations in indoor WLAN localization

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Journal of Systems Engineering and Electronics 2015年第6期26卷 1202-1209页

作者： ying Xia Zhongzhao Zhang lin Ma School of Electronics and Information Engineering Harbin Institute of Technology School of Communication and Electronic Engineering Qiqihar University

With the rapid development of wireless local area network （WLAN） technology, an important target of indoor positioning systems is to improve the positioning accuracy while reducing the online calibration effort to overcome signal time-varying. A novel fingerprint positioning algorithm, known as the adaptive radio map with updated method based on hidden Markov model （HMM）, is proposed. It is shown that by using a collection of user traces that can be cheaply obtained, the proposed algorithm can take advantage of these data to update the labeled calibration data to further improve the position estimation accuracy. This algorithm is a combination of machine learning, information gain theory and fingerprinting. By collecting data and testing the algorithm in a realistic indoor WLAN environment, the experiment results indicate that, compared with the widely used K nearest neighbor algorithm, the proposed algorithm can improve the positioning accuracy while greatly reduce the calibration effort.

关键词： subscriber location wireless local area network(WLAN) positioning accuracy calibration effort hidden Markovmodel (HMM).

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