检索结果-南通市图书馆

Optimization of mathematical models for thematic maps

在线全文

学校读者我要写书评

暂无评论

Science china(Technological sciences) 2010年第S1期53卷 15-24页

作者： QI QingWen1,ZHANG An1,jiang lili1,ZOU XiuPing2,XU li3 & CHENG Xi1,4 1 institute of Geographical sciences and Natural Resources Research,Chinese Academy of sciences,beijing 100101,china 2 institute of Policy and Management,Chinese Academy of sciences,beijing 100080,china 3 Taishan university,Taian 271021,china 4 Graduate university of Chinese Academy of sciences,beijing 100049,china institute of Geographical sciences and Natural Resources Research Chinese Academy of Sciences Beijing China institute of Policy and Management Chinese Academy of Sciences Beijing China Taishan university Taian China Graduate university of Chinese Academy of sciences Beijing China

The thematic map is a major class of maps designed to demonstrate particular features or concepts,functioning as an indispensable tool in geographical *** process of thematic mapping is one into which geographical research goes deeply and *** key activity and course of thematic map production is the use of mathematical models to create thematic data ***,the selection and optimization of mathematical models is in the forefront of thematic map *** theoretical foundations,mechanisms and methods of mathematical model optimization are expounded in this paper,including two approaches,the phase by phase mode and the multi-aim scheme balance *** studies in eco-environment mapping and emergency mapping are described and analyzed,with a hierarchical analysis method being used in the model optimization for eco-environment fragility and sensitivity assessment mapping in Beibuwan (Guangxi) District,the dynamic system (DS) method being used in the model optimization for ecological security adjustment mapping in Xishuang Banna,Yunnan province,and the multi-phase mode being used in the models for forest fire and infectious diseases mapping.

关键词： thematic map mathematic model optimization

β-delayed proton decays near the proton drip line

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2005年第3期48卷 257-267页

作者： XU Shuwei 1 , li Zhankui 1 , XIE Yuanxiang 1 , huang Wenxue 1 , SHU Nengchuan 2 , CHEN Yongshou 2 , XU Furong 3 , WANG Kun 4 , PAN Qiangyan 1 , WANG Xudong 1 , YU Yong 1 & XING Yebing 1 1. institute of Modern physics, Chinese Academy of sciences, Lanzhou 730000, china 2. Nuclear physics Department, china institute of Atomic Energy, beijing 102413, china 3. Department of Technical physics, Peking university, beijing 100871, china 4. Shanghai institute for Nuclear Research, Shanghai 201800, china institute of Modern physics Chinese Academy of Sciences Lanzhou China Nuclear physics Department China Institute of Atomic Energy Beijing China Department of Technical physics Peking University Beijing China Shanghai institute for Nuclear Research Shanghai China

We briefly reviewed the experimental study on a-delayed proton decays near the proton drip line published by our group during the period of 1996―2004, namely the first observation of the a-delayed proton decays of 9 new nuclides in the rare-earth region and the new measurements of a-delayed proton decays of 5 nuclides in the mass ～90 region near the N = Z line with the aid of the “p-?” coincidence in combination with a He-jet tape transport system. In the meantime some important experimental technique details were supplemented. The experimental results, including the half -lives, spins, parities, deformations and production reaction cross sections for the 14 nuclei were summarized and compared with the current nuclear-model predictions, and then the following points were represented. (1) The experimental half-lives for 85Mo and 92Rh as well as the predicted “waiting point” nuclei 89Ru and 93Pd are 5―10 times longer than the theoretical predictions given by M?ller et al. using a macroscopic-microscopic model. It considerably influences the predictions of the abundances of the nuclides produced in the rp-process. (2) The current-model predictions are not consistent with the experimental assignments of the spins and parities for the proton drip-line nuclei 142Ho and 128Pm. However, the nuclear potential energy surface (PES) calculated by using a Woods- Saxon-Strutinsky method reproduced the experimental results. (3) The Alice code overestimated the production reaction cross sections of the studied 9 rare-earth nuclei by one order of magnitude or two, while HIVAP code overestimated them by one order of magnitude approximately.

关键词： proton drip line, β-delayed proton decay, He-jet tape transport system, "p-γ" coincidence, spin, parity, deformation, production reaction cross section.

Recess-free enhancement-mode AlGaN/GaN RF HEMTs on Si substrate

在线全文

学校读者我要写书评

暂无评论

Journal of Semiconductors 2024年第6期45卷 81-86页

作者： Tiantian Luan Sen huang Guanjun Jing Jie Fan Haibo Yin xinguo Gao Sheng Zhang Ke Wei Yankui li Qimeng jiang Xinhua Wang Bin Hou ling Yang Xiaohua Ma Xinyu liu High-Frequency High-Voltage Device and Integrated Circuits R&D Center Institute of Microelectronics of Chinese Academy of SciencesBe i-jing 100029China School of integrated Circuits University of Chinese Academy of SciencesBeijing 100049China Faculty of integrated Circuits Xidian UniversityXi’an 710071China

Enhancement-mode(E-mode)GaN-on-Si radio-frequency(RF)high-electron-mobility transistors(HEMTs)were fabri-cated on an ultrathin-barrier(UTB)AlGaN(<6 nm)/GaN heterostructure featuring a naturally depleted 2-D electron g... 详细信息

Enhancement-mode(E-mode)GaN-on-Si radio-frequency(RF)high-electron-mobility transistors(HEMTs)were fabri-cated on an ultrathin-barrier(UTB)AlGaN(2-D electron gas(2DEG)*** fabricated E-mode HEMTs exhibit a relatively high threshold voltage(VTH)of+1.1 V with good uniformity.A maxi-mum current/power gain cut-off frequency(fT/fMAX)of 31.3/99.6 GHz with a power added efficiency(PAE)of 52.47%and an out-put power density(Pout)of 1.0 W/mm at 3.5 GHz were achieved on the fabricated E-mode HEMTs with 1-μm gate and Au-free ohmic contact.

关键词： AlGaN/GaN heterostructure ultrathin-barrier enhancement-mode radio-frequency power added efficiency silicon substrate

Geological Causes of Permeability Heterogeneity in a Fractured Sandstone-Mudstone Rock Mass in the Xiaolangdi Dam Site,Central china

在线全文

学校读者我要写书评

暂无评论

地学前缘 2009年第S1期16卷 16-17页

作者： Xiaowei jiang~1,Wan li~1,Xusheng Wang~1,Aibin Kang~1,Jun huang~(2,3),Guoxing huang~1 1.School of Water Resources & Environment,china university of Geosciences(beijing),beijing 100083,china. 2.Research Center of Tunneling and Underground Engineering,beijing Jiaotong university,beijing 100044,china 3.china Highway Planning and Design institute(HPDI) Consultants,INC,beijing 100010,china

Heterogeneity of permeability in fractured media is a hot research topic in hydrogeology and numerous approaches had been proposed to characterize heterogeneity in the past several ***。

关键词： fractured media permeability heterogeneity declustering distribution of mudston

Phase reconfiguration of heterogeneous CoFeS/CoNiS nanoparticles for superior battery-type supercapacitors

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第9期96卷 217-225页

作者： lina Ma Fan li Min Zhou Jidong Dong Hao Luo Wei Zhang Wenchao Zhao Xinliang li Zaixing jiang Yudong huang college of Chemistry and Chemical Engineering Qingdao UniversityQingdao 266071ShandongChina School of Materials Science and Engineering Xiamen University of TechnologyXiamen 361024FujianChina Co-Innovation Center of Efficient Processing and Utilization of Forest Resources College of Materials Science and EngineeringNanjing Forestry UniversityNanjing 210037JiangusChina Key Laboratory of Material physics Ministry of EducationSchool of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450052HenanChina MIIT Key Laboratory of Critical Materials technology for New Energy Conversion and Storage State Key Laboratory of Urban Water Resource and EnvironmentSchool of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001HeilongjiangChina Material Science and Engineering college Northeast Forestry UniversityHarbin 150040HeilongjiangChina

Developing advanced battery-type materials with abundant active sites,high conductivity,versatile morphologies,and hierarchically porous structures is crucial for realizing high-quality hybrid ***,heterogeneous FeS@NiS is synthesized by cationic Co doping via surface-structure *** density functional theory(DFT)theoretical calculations are firstly performed to predict the advantages of Co dopant by improving the OH^(−)adsorption properties and adjusting electronic structure,benefiting ions/electron *** dynamic surface evolution is further explored which demonstrates that CoFeS@CoNiS could be quickly reconstructed to Ni(Co)Fe_(2)O_(4)during the charging process,while the unstable structure of the amorphous Ni(Co)Fe_(2)O_(4)results in partial conversion to Ni/Co/FeOOH at high potentials,which contributes to the more reactive active site and good structural ***,the free-standing electrode reveals excellent electrochemical performance with a superior capacity(335.6 mA h g^(−1),2684 F g^(−1))at 3 A g^(−1).Furthermore,the as-fabricated device shows a quality energy density of 78.1 W h kg^(−1)at a power density of 750 W kg^(−1)and excellent cycle life of 92.1%capacitance retention after 5000 *** work offers a facile strategy to construct versatile morphological structures using electrochemical activation and holds promising applications in energy-related fields.

关键词： In-situ reconfiguration Heterogeneous design Battery-type supercapacitors Superior performance Sulphide

High sensitivity of semimetal photodetection via Bose–Einstein condensation

在线全文

学校读者我要写书评

暂无评论

InfoMat 2024年第2期6卷 142-151页

作者： Tuntan Wu Qinxi Qiu Yongzhen li Qiangguo Zhou Wanli Ma Jingbo li lin jiang Wei Zhou Zhiming huang State Key Laboratory of Infrared physics Shanghai Institute of Technical PhysicsChinese Academy of SciencesShanghaithe People's Republic of China Hangzhou institute for Advanced Study University of Chinese Academy of SciencesHangzhouthe People's Republic of China university of Chinese Academy of sciences Beijingthe People's Republic of China institute of Optoelectronics Fudan UniversityShanghaithe People's Republic of China Key Laboratory of Space Active Optical-Electro technology Chinese Academy of SciencesShanghaithe People's Republic of China

The discovery of semiconductor has witnessed remarkable strides toward high performance of photodetectors attributed to its excellent carrier ***,semimetal,owning to the high carrier concentration and low carrier mobility compared to those of semiconductor,is generally considered unsuitable for ***,we demonstrate an outstanding photodetection in a layered semimetal titanium diselenide(TiSe_(2))in Bose-Einstein condensation(BEC)*** sensitivity of semimetal photodetector is realized in the range of visible,infrared and terahertz *** noise equivalent power(NEP)has threefold improvement at the visible and infrared wavebands,and significant decrease by one order of magnitude in the terahertz frequencies via BEC phenomenon,attributed to the electrical parameter variation after *** best NEP value in the terahertz frequency is comparable to that of commercial Si *** results show another recipe to fabricate high performance of photodetection via semimetal except for semiconductor and pave the way to exploit macroscopic quantum phenomena for optoelectronics.

关键词： Bose-Einstein condensation electromagnetic induced well effect photodetector semimetal

Provenance of colorless and brown volcanic glass in late Pleistocene tephra layers in the Western Philippine Sea

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 Oceanology and limnology 2024年第5期42卷 1438-1449页

作者： Fuqing jiang Zhishun ZHANG Zhaohui ZHANG Guoliang ZHANG Peng huang Xiaojing ZHOU Zhifang XIONG Congying li Tiegang li Key Laboratory of Ocean Observation and Forecasting and Key Laboratory of Marine Geology and Environment Institute of OceanologyChinese Academy of SciencesQingdao 266071China Laboratory for Marine Geology Qingdao Marine Science and Technology CenterQingdao 266237China university of Chinese Academy of sciences Beijing 100049China institute of Marine Chemistry and Environment Ocean CollegeZhejiang UniversityZhoushan 316021China college of Marine technology and Environment Dalian Ocean UniversityDalian 116023China Key Laboratory of Marine Sedimentology and Environmental Geology First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China

Tephra layers in the western Philippine Sea,characterized by abundant volcanic glass shards,may provide crucial evidence on the eruption history of volcanoes and tectonic evolution of the western Pacific.A 220-ka sediment core from the Benham Rise in the western Philippine Sea offers new insights into the provenance of four intercalated tephra layers(T1–T4,in chronological order)containing either colorless or brown glass *** to primitive mantle,all glass shards are enriched in large-ion lithophile elements,such as Rb,Cs,and Pb,and depleted in high field-strength elements,such as Th,Nb,and Ta,indicating a subduction-related *** colorless glass shards are characterized by high SiO_(2)(>78%)and light rare earth element(LREE)contents as well as high La/Sm ratios(>9),low FeO and MgO contents(1%),low Sr/Y(15)and high Ba/Th ratios(>100),pointing to a rhyolitic composition and a medium-K calc-alkaline serial *** contrast,the brown glass shards are characterized by lower SiO_(2)(3%)and LREE contents,higher FeO,MgO,and CaO contents,lower La/Sm(15),indicating derivation from medium to high-K calc-alkaline andesite *** glass shards from layers T3(152 ka)and T4(172 ka)were correlated with volcanic deposits from the Taal and Laguna Caldera in the Maccolod Corridor,respectively,while the colorless glass shards from layers T1(36.5 ka)and T2(61.2 ka)were likely sourced from the Irosin Caldera in the Bicol *** the provenance of late Pleistocene tephra layers in the western Philippine Sea is helpful to complement a Philippine volcanic history and establish a regional tephrochronostratigraphy.

关键词： volcanic glass provenance chemical composition Philippine Sea late Pleistocene

Identification and characterization of camptothecin tailoring enzymes in Nothapodytes tomentosa

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2024年第6期66卷 1158-1169页

作者： Yin Chen Jian-Ping huang Yong-jiang Wang Meng-ling Tu Junheng li Bingyan Xu Guoqing Peng Jing Yang Sheng-Xiong huang State Key Laboratory of Phytochemistry and Plant Resources in West china and Yunnan Key Laboratory of Natural Medicinal Chemistry Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China university of Chinese Academy of sciences Beijing 100049China Key Laboratory for Economic Plants and Biotechnology Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China

Camptothecin is a complex monoterpenoid indole alkaloid with remarkable antitumor *** that two C-10 modified camptothecin derivatives,topotecan and irinotecan,have been approved as potent anticancer agents,there is a critical need for methods to access other aromatic ringfunctionalized congeners(e.g.,C-9,C-10,etc.).However,contemporary methods for chemical oxidation are generally harsh and low-yielding when applied to the camptothecin scaffold,thereby limiting the development of modified *** herein,we have identified four tailoring enzymes responsible for C-9 modifications of camptothecin from Nothapodytes tomentosa,via metabolomic and transcriptomic *** consist of a cytochrome P450(Nt CPT9H)which catalyzes the regioselective oxidation of camptothecin to 9-hydroxycamptothecin,as well as two methyltransferases(Nt OMT1/2,converting 9-hydroxycamptothecin to 9-methoxycamptothecin),and a uridine diphosphate-glycosyltransferase(Nt UGT5,decorating 9-hydroxycamptothecin to9-β-D-glucosyloxycamptothecin).Importantly,the critical residues that contribute to the specific catalytic activity of Nt CPT9H have been elucidated through molecular docking and mutagenesis *** work provides a genetic basis for producing camptothecin derivatives through metabolic *** will hasten the discovery of novel C-9 modified camptothecin derivatives,with profound implications for pharmaceutical manufacture.

关键词： camptothecin biosynthesis enzymatic assay Nothapodytes tomentosa tailoring enzyme transcriptomic analysis

Characteristics and influencing factors of greenhouse gas emissions from reservoirs in the Yellow River Basin:A Meta-analysis

在线全文

学校读者我要写书评

暂无评论

Science china Earth sciences 2024年第7期67卷 2210-2225页

作者： Shurui huang Peijia ZHANG Wenxiu ZHENG Jiajia ZHANG Yang li Yuanjian WANG Enhui jiang Shaoda liU Xinghui XIA State Key Laboratory of Water Environment Simulation School of EnvironmentBeijing Normal UniversityBeijing 00875China Yellow River institute of Hydraulic Research Yellow River Conservancy CommissionZhengzhou 450003China

Reservoir construction and operation profoundly alter the hydrological,hydrodynamic,and carbon and nitrogen cycling processes of ***,current research still lacks a systematic understanding of the characteristics of greenhouse gas(GHG)emissions from reservoirs in arid/semi-arid *** study integrates existing monitoring data to discuss the characteristics of GHG emissions from reservoirs in the Yellow River Basin and illustrate the controlling factors and underlying mechanism of these *** results indicate that while CO_(2) emission flux from reservoirs is lower than that from river channels,the emission fluxes of CH_(4) and N_(2)O are 1.9 times and 10 times those from rivers,respectively,indicating that the emission of GHG with stronger radiative effect is significantly enhanced in *** to the reservoirs in humid climates(e.g.,the Three Gorges Reservoir),reservoirs in the Yellow River Basin exhibit relatively lower emissions of CO_(2) and CH_4 due to lower organic matter concentrations,but significantly higher N_(2)O emissions due to higher nitrogen *** Carlo simulations for 237 reservoirs in the Yellow River Basin showed that total emission of the three GHGs is 3.05 Tg CO_(2)-eq yr^(-1),accounting for 0.39% of the total emission from global reservoirs and lower than the area percentage of the basin(0.53%).This study has important implications on revealing the GHG emission characteristics and control mechanisms of reservoirs in arid/semi-arid regions.

关键词： Yellow River Basin Reservoir Greenhouse gas Emission flux Water quality