检索结果-南通市图书馆

Green synthesis of MnO_x nanostructures and studies of their supercapacitor performance

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2015年第4期58卷 627-633页

作者： Wei Du xiaoqian Xu Di Zhang Qingyi lu Feng Gao State Key laboratory of Coordination Chemistry Nanjing National laboratory of Microstructures Coordination Chemistry Institute School of Chemistry and Chemical Engineering Nanjing University Department of Materials Science and Engineering Nanjing University

Manganese oxides with different crystalline phases and morphologies were prepared by calcining Mn CO3 precursors. The Mn CO3 precursors with different morphologies were obtained through a green route under hydrothermal conditions with orange pericarp extracting solution as the reducing agent. By calcining the precursor under different temperatures and atmospheres, Mn Ox with different stoichiometric ratios(i.e., Mn O, Mn O2, Mn2O3, and Mn3O4) can be obtained. Electrochemical studies reveal that among these manganese oxides, Mn O or Mn O2 are more suitable as supercapacitor working electrodes than Mn2O3 or Mn3O4. They exhibit high specific capacitance up to 296.6 F/g and also possess good cycling stability, which make them potential electrode materials for supercapacitors.

关键词： MnOx nanostructures green synthesis supercapacitor

Research on 3‐D total electric field of crossing high voltage direct current transmission lines based on upstream finite element method

在线全文

学校读者我要写书评

暂无评论

High Voltage 2021年第1期6卷 160-170页

作者： xiaoqian Ma li Xie Kun He Jiayu lu Department of High Voltage China Electric Power Research InstituteBeijingChina Department of Electrical Engineering Tsinghua UniversityBeijingChina

The ongoing large‐scale construction of ultra high voltage direct current projects in China makes the crossing of two high voltage direct current(HVDC)lines *** is critical to study the characteristics and calculation method of 3‐D total electric fields of crossing HVDC *** problems encountered when applying the 3‐D upstream finite element method to calculate total electric field of crossing HVDC lines and the solutions are studied in this *** view of the surface electric field varying greatly along longitudinal direction of conductors,the calculation method adopting the Davidon‐Fletcher‐Powell optimization algorithm is introduced to realize the fast computation of 3‐D space‐charge‐free *** the distinct corona intensity at different positions of conductors,a new for-mula for initializing charge density is studied to ensure the convergence of calculation *** the large computation amount of total electric field,an adaptive iteration strategy is put forward to effectively speed up the *** measurement of ground total electric field underneath a crossing HVDC test line is conducted to verify the validity of the proposed calculation *** distribution characteristics of electric fields of crossing HVDC lines are calculated and *** research results will provide technical support for the design and environmental impact assessment of crossing HVDC transmission lines.

关键词： calculation field element

Reconstruction of sub cross-correlation cancellation technique for unambiguous acquisition of BOC(kn, n) signals

维普期刊数据库评论

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 Systems Engineering and Electronics 2019年第5期30卷 852-860页

作者： JI Yuanfa CHEN xiaoqian FU Qiang SUN Xiyan ZHEN Weimin Guangxi Key laboratory of Precision Navigation Technology and Application Guilin University of Electronic TechnologyGuilin 541004China National&local Joint Engineering Research Center of Satellite Navigation Positioning and location Service Guilin 541004China Key laboratory of Radio Wave Environment and Modeling Technology Qingdao 266000China

In order to solve the problem of ambiguous acquisition of BOC signals caused by its property of multiple peaks,an unambiguous acquisition algorithm named reconstruction of sub cross-correlation cancellation technique(RSCCT)for BOC(kn,n)signals is *** this paper,the principle of signal decomposition is combined with the traditional acquisition algorithm structure,and then based on the method of reconstructing the correlation *** method firstly gets the sub-pseudorandom noise(PRN)code by decomposing the local PRN code,then uses BOC(kn,n)and the sub-PRN code cross-correlation to get the sub cross-correlation ***,the correlation peak with a single peak is obtained by reconstructing the sub cross-correlation function so that the ambiguities of BOC acquisition are *** simulation shows that RSCCT can completely eliminate the side peaks of BOC(kn,n)group signals while maintaining the narrow correlation of BOC,and its computational complexity is equivalent to sub carrier phase cancellation(SCPC)and autocorrelation side-peak cancellation technique(ASPeCT),and it reduces the computational complexity relative to *** BOC(n,n),the acquisition sensitivity of RSCCT is 3.25 dB,0.81 dB and 0.25 dB higher than binary phase shift keying(BPSK)-like,SCPC and ASPeCT at the acquisition probability of 90%,*** peak to average power ratio is 1.91,3.0 and 3.7 times higher than ASPeCT,SCPC and BPSK-like at SNR=–20 dB,*** BOC(2n,n),the acquisition sensitivity of RSCCT is 5.5 dB,1.25 dB and 2.69 dB higher than BPSK-like,SCPC and ASPeCT at the acquisition probability of 90%,*** peak to average power ratio is 1.02,1.68 and 2.12 times higher than ASPeCT,SCPC and BPSK-like at SNR=–20 dB,respectively.

关键词： signal decomposition sub cross-correlation reconstructingcorrelation function acquisition performance

Highly responsive biosensors based on organic field-effect transistors under light irradiation

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical letters 2021年第11期32卷 3364-3367页

作者： xiaoqian Jiang Chenfang Sun Congcong Zhang Shanshan Cheng Department of Chemistry Tianjin Key Laboratory of Molecular Optoelectronic Sciences School of ScienceTianjin UniversityTianjin 300072China Institute for Advanced Interdisciplinary Research University of JinanJi'nan 250011China

High responsivity and sensitivity play essential roles in the development of organic field-effect transistors(OFETs)-based biosensors with regard to biological detections,particularly for disease ***,how to design a biosensor which improves these two outstanding properties while achieving low cost,easy processing,and time saving is a daunting ***,a novel biosensor based on OFET with copolymer thin film,whose surface is illuminated with a suitable light beam is *** film can be used as both an organic semiconductor material and as a photoelectric active *** to amplification of signals as a result of the film’s strong response to light,the biosensor possesses higher responsivity and sensitivity compared to dark condition and even realizes a maximum responsivity of up to 10^(3)for alpha-fetoprotein(AFP)*** simple combination of light and transistor builds a bridge between photoelectric effect and biological *** addition,the emergence of more excellent photoelectric active materials is expected to pave a way for ultrasensitive bio-chemical diagnostic tools.

关键词： Organic field-effect transistors Photoelectric active materials Photo response Biosensors Disease diagnosis

Catalytic performances of heteropoly compounds supported on dealuminated ultra-stable Y zeolite for liquid-phase esterification

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2006年第2期49卷 140-147页

作者： ZHANG Fumin WANG Jun YUAN Chaoshu REN xiaoqian Key laboratory of Materials-Oriented Chemical Engineering of Jiangsu Province College of Chemistry and Chemical EngineeringNanjing University of TechnologyNanjing 210009China

A series of catalysts of 12-Phosphotungstic acid(PW)and its cesium salts immobilizedon dealuminated ultra-stable Y zeolite(DUSY)were *** specific surface area and acidstrength were characterized,and their catalytic activity,selectivity and stability were evaluated in theliquid-phase esterification of acetic acid with *** was found that the catalytic activity could beimproved remarkably by introducing PW onto dealuminated USY(from 49.5%to 86.4%).Howeverthis obvious promotion effect of PW could not be observed on USY supported PW catalyst,whichshowed rather low conversion of less than 25.0%.The supported cesium salt of PW on DUSY catalysgave a very high conversion of n-butanol of 94.6%and the 100%selectivity for n-butyl *** stability test revealed that after 5 reaction cycles,the catalytic activity over PW/DUSY drastically dropped to 47.6%,by contrast,the PW cesium salt/DUSY still showed a high conversion o81.6%.The leaching test for catalysts in water showed that the decrease of activity was closely associated with the solubility of the active heteropoly components on supports into the polar solvent,whichindicates that the catalytic deactivation was mainly due to the lose of the heteropoly species in thereaction *** high catalytic stability of the supported cesium salts of PW is suggested to bederived from the water-tolerance of cesium salts of PW in the polar reaction system.

关键词： heteropoly acid 12-phosphotungstic acid Cs-salts of 12-phosphotungstic acid USY esterification n-butanol.

Attitude control system design and on-orbit performance analysis of nano-satellite––‘‘Tian Tuo 1’’

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2014年第3期27卷 593-601页

作者： Ran Dechao Sheng Tao Cao lu Chen xiaoqian Zhao Yong College of Aerospace Science and Engineering National University of Defense Technology

＂Tian Tuo 1＂（TT-1） nano-satellite is the first single-board nano-satellite that was suc- cessfully launched in China. The main objective of TT-1 is technology demonstration and scientific measurements. The satellite carries out the significant exploration of single-board architecture fea- sibility validation, and it is tailored to the low-cost philosophy by adopting numerous commercial- off-the-shelf （COTS） components. The satellite is featured with three-axis stabilization control capability. A pitch bias momentum wheel and three magnetic coils are adopted as control actuators. The sun sensors, magnetometers and a three-axis gyro are employed as the measurement sensors. The quaternion estimator （QUEST） and unscented Kalman filter （UKF） method are adopted for the nano-satellite attitude determination. On-orbit data received by ground station is conducted to analysis the performance of attitude determination and control system （ADCS）. The results show that the design of ADCS for TT-1 is suitable, robust and feasible.

关键词： Actuators ADCS On-orbit performance Sensors TT-1 nano-satellite

A machine learning surrogate modeling benchmark for temperature field reconstruction of heat source systems

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2023年第5期66卷 162-181页

作者： xiaoqian CHEN Zhiqiang GONG Xiaoyu ZHAO Weien ZHOU Wen YAO Defense Innovation Institute Chinese Academy of Military Science

The temperature field reconstruction of heat source systems(TFR-HSS) with limited monitoring sensors in thermal management plays an important role in the real-time health detection systems of electronic equipment in engineering. However, prior methods with common interpolations usually cannot provide accurate reconstruction performance as required. In addition, no public dataset exists for the wide research of reconstruction methods to further boost reconstruction performance and engineering applications. To overcome this problem, this work develops a machine learning surrogate modeling benchmark for the TFRHSS task. First, the TFR-HSS task is mathematically modeled from a real-world engineering problem, and four types of computational modelings are constructed to transform the problem into discrete mapping ***, this work proposes a set of machine learning surrogate modeling methods, including general machine learning methods and deep learning methods, to advance the state-of-the-art methods over temperature field reconstruction. More importantly, this work develops a novel benchmark dataset, namely the temperature field reconstruction dataset(TFRD), to evaluate these machine learning surrogate modeling methods for the TFR-HSS task. Finally, a performance analysis of typical methods is given on the TFRD, which can serve as the baseline results on this benchmark.

关键词： temperature field reconstruction heat-source systems computational modeling temperature field reconstruction dataset machine learning surrogate modeling deep learning

Seasonal Variation of Environmental Variables and Phytoplankton Community Structure and Their Relationship in liaodong Bay of Bohai Sea,China

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2018年第4期17卷 864-878页

作者： YANG Guojun WU Zhongxin SONG lun lU xiaoqian College of Fisheries and life Science Dalian Ocean UniversityDalian 116023China Center for Marine Ranching Engineering Science Research of liaoning Province Dalian Ocean UniversityDalian 116023China College of Marine Science and Environment Dalian Ocean UniversityDalian 116023China liaoning Ocean and Fisheries Science Research Institute Dalian 116023China

In this paper, systematic studies on the changes in concentrations of the environmental factors and the net-phytoplankton community, and the relationship between them in the liaodong Bay, Bohai Sea during 2013 are presented. The PCA results showed that higher levels of nutrients and dissolved heavy metals in the river-estuary-bay system were closely related to the river runoff. Since the influences of industrial and anthropogenic activities, the liaodong Bay coastal areas are facing a huge environmental challenge of nutrients and heavy metal pollution. Net-phytoplankton community structure showed obvious seasonal succession, among which the dominant and(or) key species were the main factors affecting community structure change and stability. Under certain environmental conditions, the dominant species and(or) key species dominated the phytoplankton community structure succession. The Bio-ENV results suggested that the seawater temperature, nutrient, Cu, Pb, Zn, and Cd in liaodong Bay are important environmental variables that affect the phytoplankton community structure. Anthropogenic activities have significantly contributed to the changes in concentrations of environmental factors and the net-phytoplankton community structure and stability, and the relationship between them.

关键词： liaodong Bay environmental variables eutrophication trace metals phytoplankton community ecological stability

Forced expression of the Oct-4 gene influences differentiation of embryonic stem cells

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2001年第17期46卷 1446-1449页

作者： Zhongwei Du xiaoqian Cong Zhen Yao Chinese Acad Sci Shanghai Inst Biol Sci Inst Biochem & Cell Biol Shanghai 200031 Peoples R China

By transfecting an Oct-4 expression plasmid into embryonic stem cells (ES cells), the ES-O cell line was constructed, which sustained the expression of Oct-4 gene when induced by retinoic acid. Forced expression of Oct-4 gene could not sustain the stem property of ES-O cells without the differentiation inhibiting factor lIF, but if lIF exists, forced expression of Oct-4 gene could enhance the ability to sustain the undifferentiation state and inhibit cell differentiation induced by retinoic acid. It was indicated that Oct-4 must cooperate with lIF to sustain the undifferentiation state of ES cells. During the cell differentiation, ES-O cells tend to differentiate into neural cells, suggesting that forced expression of Oct-4 gene may be in relation with the differentiation of neuroderm.

关键词： Oct-4 gene embryonic stem cell differentiation.