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Enhancement of the Photoelectric Performance of Dye-sensitized Solar Cells by Sol-gel Modified TiO_2 Films

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Journal of Materials Science & Technology 2011年第8期27卷 764-768页

作者： Yunfeng Zhao Xiaojie li qiuping li Changsheng Deng Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China PetroChina Pipeline R&D Center Langfang 065000 China ENN Science Technology Development Co. Ltd. Langfang 065000 China

Modified TiO2 films have been prepared by combining commercial titania powders （Degussa P25） with sol-gel made by titanium chloride （Ti-sol）. The result shows that clusters are formed by nanoparticles and large pores can be seen on the surface of the TiO2 films. The short circuit photocurrent density and photoelectric conversion efficiency of the solar cells are obviously enhanced compared with those without modification. The relationship between the photoelectric conversion efficiency and the amount of Ti-sol was investigated. With the addition of 30 wt% Ti-sol, the photoelectric conversion efficiency as high as 9.75% is achieved, increasing by 28.3% compared with the solar cells without modification.

关键词： Sol-gel Titanium dioxide Dye-sensitized solar cells

Current-carrying tribological behavior of C/Cu contact pairs in extreme temperature and humidity environments for railway catenary systems

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Science China(Technological Sciences) 2024年第8期67卷 2537-2548页

作者： SHEN MingXue JI DeHui HU Qiang XIAO li li qiuping State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong UniversityNanchang 330013China School of Materials Science and Engineering East China Jiaotong UniversityNanchang 330013China Institute of Applied Physics Jiangxi Academy of SciencesNanchang 330095China

Many current-carrying contact pairs, such as those found in pantograph-catenary systems, operate in open environments and are susceptible to significant external interference from temperature and humidity variations. This study investigated the evolution of the friction coefficient and contact resistance of C/Cu contact pairs under alternating temperature, humidity, and current conditions. Through experimentation, the wear rate and microtopography of the worn surface were analyzed under various constant parameters. Subsequently, the differences in tribological behavior and current-carrying characteristics of the contact pairs under these three parameters were explored. The results revealed that the decrease in temperature resulted in a significant increase in the friction coefficient of the contact pairs, carbon wear, and copper surface roughness. Additionally, the surface oxidation rate was lower at lower temperatures. Moreover, contact resistance did not consistently increase with decreasing temperature, owing to the combined action of the contact area and the oxide film. Compared with temperature, humidity fluctuations at room temperature exerted less influence on the friction coefficient and contact resistance of the contact pairs. Dry environments rendered carbon materials vulnerable to oxidation and cracking, while excessive humidity fostered abrasive wear and arcing. High-current conditions generally degraded the tribological properties of C/Cu contacts. In the absence of current, the friction coefficient was extremely high, and the copper transfer was high. Under excessive current, copper was susceptible to plowing by carbon micro-bumps and abrasive particles, resulting in a decrease in the friction coefficient. The release of lipids from the carbon surface due to temperature elevation weakened the electrical contact performance and increased the occurrence of arc erosion, thereby exacerbating carbon wear.

关键词： temperature/humidity pantograph-catenary system C/Cu wear current-carrying friction sliding electrical contact

Mining hourly population dynamics by activity type based on decomposition of sequential snapshot data

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International Journal of Digital Earth 2022年第1期15卷 1395-1416页

作者： Qingli Shi li Zhuo Haiyan Tao qiuping li Guangdong Provincial Key Laboratory of Urbanization and Geo-simulation School of Geography and PlanningSun Yat-sen UniversityGuangzhouPeople’s Republic of China Guangdong Provincial Engineering Research Centre for Public Security and Disaster GuangzhouPeople’s Republic of China Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) ZhuhaiPeople’s Republic of China

The dynamic population distributions by activity type(***,shopping or in-home)are vital for resource allocation,urban planning and epidemic *** studies have incorporated individual-level human mobility data to map population distribution by activity type,access to such data is hindered due to privacy issues and they rely on auxiliary data to provide priori activity *** paper presents a method for generating the population dynamics by activity *** first introduce more readily available sequential snapshot data to construct the population mixture model,then decompose the population mixture,and finally estimate the dynamic population size for each *** test the method in the central districts of Guangzhou city,China,based on real-time Tencent user density *** analysis and accuracy assessment prove that our method can accurately estimate hourly distributions for populations engaging in working,stay-at-home,and socializing *** temporal distribution of the working population reproduces the regular work scenarios and socializing population displays complex spatial *** also find that there is an underlying relationship between a region’s function and its dynamic population *** presented method has great potential for application and could provide new insight for studying urban dynamic functions.

关键词： Hourly population dynamics activity type population mixture model real-time Tencent user density data

Energy-Efficient Computation Offloading and Resource Allocation in Fog Computing for Internet of Everything

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China Communications 2019年第3期16卷 32-41页

作者： qiuping li Junhui Zhao Yi Gong Qingmiao Zhang School of Electronic and Information Engineering Beijing Jiaotong UniversityBeijing 100044China School of Information Engineering East China Jiaotong UniversityNanchang 330013China Shenzhen Engineering Laboratory of Intelligent Information Processing for IoT Southern University of Science and TechnologyShenzhen 518055China

With the dawning of the Internet of Everything(IoE) era, more and more novel applications are being deployed. However, resource constrained devices cannot fulfill the resource-requirements of these applications. This paper investigates the computation offloading problem of the coexistence and synergy between fog computing and cloud computing in IoE by jointly optimizing the offloading decisions, the allocation of computation resource and transmit power. Specifically, we propose an energy-efficient computation offloading and resource allocation(ECORA) scheme to minimize the system cost. The simulation results verify the proposed scheme can effectively decrease the system cost by up to 50% compared with the existing schemes, especially for the scenario that the computation resource of fog computing is relatively small or the number of devices increases.

关键词： fog computing cloud computing resource allocation computation offloading IoE

Irregular initial solidification by mold thermal monitoring in the continuous casting of steels:A review

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 1003-1015页

作者： qiuping li Guanghua Wen Fuhang Chen Ping Tang Zibing Hou Xinyun Mo College of Materials Science and Engineering Chongqing UniversityChongqing 400044China Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New Materials Chongqing UniversityChongqing 400044China

Occasional irregular initial solidification phenomena,including stickers,deep oscillation marks,depressions,and surface cracks of strand shells in continuous casting molds,are important limitations for developing the high-efficiency continuous casting of *** application of mold thermal monitoring(MTM) systems,which use thermocouples to detect and respond to temperature variations in molds,has become an effective method to address irregular initial solidification *** systems are widely applied in numerous steel companies for sticker breakout ***,monitoring the surface defects of strands remains ***,indepth research is necessary to utilize the potential advantages and comprehensive monitoring of MTM *** paper summarizes what is included in the irregular initial solidification phenomena and systematically reviews the current state of research on these phenomena by the MTM ***,the influences of mold slag behavior on monitoring these phenomena are ***,the remaining problems of the formation mechanisms and investigations of irregular initial solidification phenomena are discussed,and future research directions are proposed.

关键词： irregular initial solidification mold thermal monitoring continuous casting mold slag thermocouple

Determination of Fe^(2+)/Fe^(3+)Ratios of Magnetite using Different Methods:A Case Study from the Qimantag Metallogenic Belt

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Acta Geologica Sinica(English Edition) 2022年第6期96卷 2135-2147页

作者： YI liwen li qiuping LU Anhuai GU Xiangping CHI Guoxiang School of Geographical Sciences Hunan Normal UniversityChangsha 410081China School of Geosciences and Info-Physics Central South UniversityChangsha 410083China School of Earth and Space Sciences Peking UniversityBeijing 100871China Department of Geology University of ReginaReginaSaskatchewan S4S 0A2Canada

Determination of Fe^(2+)/Fe^(3+) ratios from metallogenic belts to explore controlling physical and chemical conditions of rock formation is of great *** order to explore magnetite Fe^(2+)/Fe^(3+) ratios of the Qimantag metallogenic belt,part of the Eastern Kunlun orogenic belt in the northeastern margin of the Qinghai–Tibetan plateau,western Central Orogenic Belt of China,and overcome the limitation of the traditional electronic probe,five different measurement methods are proposed and their respective advantages and disadvantages evaluated,with the composition data of the magnetite obtained using electron probe microanalysis(EPMA).The direct oxygen measurement method has a significant impact on the determination results of FeO and Fe2O3,but the accuracy and uniformity of the results are *** valence method(Flank method)based on the spectral intensity ratio of Lαto Lβfor iron is also unreliable for FeO and Fe_(2)O^(3) measurements because it is difficult to establish a relationship between Lβ/Lα,the spectral intensity ratio,and the Fe^(2+)/Fe^(3+) content *** comparison,the charge difference method,the surplus-oxygen method and the Mössbauer spectrum method are still the most favorable.Mössbauer spectroscopy,with its isomer movement particularly sensitive to the oxidation state of iron,yields results closer to 0.5,which is relatively *** magnetite deposits are located in intrusions or contact zones and formed by magmatic fluids with high Fe2+/Fe3+ratios,whereas later magnetite deposits are farther away from intrusions and have low Fe^(2+)/Fe^(3+) *** transformation mechanism of hematite and magnetite in the Qimantage metallogenic belt is also *** large volume changes,such as pore filling and shrinkage fracture,were detected in the metallogenic belt,and the transformation mechanism is more similar to a reoxidation and reduction mechanism.

关键词： iron magnetite direct oxygen measurement flank-charge difference-surplus-oxygen methods Mössbauer spectra Qimantage

Intestinal Microbiota in Early life and Its Implications on Childhood Health

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Genomics, Proteomics & Bioinformatics 2019年第1期17卷 13-25页

作者： Lu Zhuang Haihua Chen Sheng Zhang Jiahui Zhuang qiuping li Zhichun Feng Affiliated Bayi Children's Hospital The Seventh Medical Center of PLA General Hospital National Engineering Laboratory for Birth Defects Prevention and Control of Key Technology Beijing Key Laboratory of Pediatric Organ Failure The First Clinical Academy of Dalian Medical University College of the Environment Northeast Normal University

Trillions of microbes reside in the human body and participate in multiple physiological and pathophysiological processes that affect host health throughout the life cycle. The microbiome is hallmarked by distinctive compositional and functional features across different life *** evidence has shown that microbes residing in the human body may play fundamental roles in infant development and the maturation of the immune system. Gut microbes are thought to be essential for the facilitation of infantile and childhood development and immunity by assisting in breaking down food substances to liberate nutrients, protecting against pathogens, stimulating or modulating the immune system, and exerting control over the hypothalamic–pituitary–adrenal *** review aims to summarize the current understanding of the colonization and development of the gut microbiota in early life, highlighting the recent findings regarding the role of intestinal microbes in pediatric diseases. Furthermore, we also discuss the microbiota-mediated therapeutics that can reconfigure bacterial communities to treat dysbiosis.

关键词： Intestinal microbiota Immunity Gut-brain axis Early life Diseases Microbiota manipulation

Mathematical model of oxygen outdiffusion

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中国有色金属学会会刊：英文版 1994年第3期4卷 71-76页

作者： liu Rong Cheng, qiuping li Yidong She Siming(Central South University of Techology Chngsha 410083) Central South Univ of Technology Changsha China

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关键词： CZSi outdiffusion intrinsic gettering

Implementation of PRINCE with resource-efficient structures based on FPGAs

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Frontiers of Information Technology & Electronic Engineering 2021年第11期22卷 1505-1516页

作者： Lang li Jingya FENG Botao liU Ying GUO qiuping li Hunan Provincial Key Laboratory of Intelligent Information Processing and Application Hengyang Normal UniversityHengyang421002China College of Information Science and Engineering Hunan Normal UniversityChangsha410081China College of Computer Science and Technology Hengyang Normal UniversityHengyang421002China

In this era of pervasive computing, low-resource devices have been deployed in various fields. PRINCE is a lightweight block cipher designed for low latency, and is suitable for pervasive computing applications. In this paper, we propose new circuit structures for PRINCE components by sharing and simplifying logic circuits, to achieve the goal of using a smaller number of logic gates to obtain the same result. Based on the new circuit structures of components and the best sharing among components,we propose three new hardware architectures for PRINCE. The architectures are simulated and synthesized on different programmable gate array devices. The results on Virtex-6 show that compared with existing architectures, the resource consumption of the unrolled, low-cost, and two-cycle architectures is reduced by 73, 119, and 380 slices, respectively. The low-cost architecture costs only 137 slices. The unrolled architecture costs 409 slices and has a throughput of 5.34 Gb/s. To our knowledge, for the hardware implementation of PRINCE, the new low-cost architecture sets new area records, and the new unrolled architecture sets new throughput records. Therefore, the newly proposed architectures are more resource-efficient and suitable for lightweight,latency-critical applications.

关键词： lightweight block cipher Field-programmable gate array(FPGA) Low-cost PRINCE Embedded security