检索结果-南通市图书馆

Geochronology and Geochemistry of the Early Permian A-Type Granite in the Hongol Area, Central Inner Mongolia:Petrogenesis and Tectonic Implications

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

Acta Geologica Sinica(English Edition) 2018年第3期92卷 988-1007页

作者： ZHANG Xiangxin gao Yongfeng LEI Shihe College of Resource Science Hebei GEO University

We performed geochronological and geochemical analyses of the A-type granite in the Hongol area, central Inner Mongolia, to determine its age, petrogenesis and tectonic setting, which are significant for clarifying the Late Paleozoic tectonic evolution of the Xing’an Mongolian Orogenic Belt(XMOB). The rock type of the A-type granite in the Hongol area is alkali-feldspar granite, and it constitutes a western part of the Baiyinwula-Dongujimqin A-type granite belt. Zircon U-Pb geochronology yieldsPb/U ages ranging from 293 to 286 Ma for the alkali-feldspar granite, indicating this granitic pluton formed in the Early Permian. The alkali-feldspar granite is high in silica(SiO=75.13 wt%-80.17 wt%), aluminum(AlO=10.59 wt%-13.17 wt%) and alkali(NaO+KO=7.33 wt%-9.11 wt%), and low in MgO(0.08 wt%-0.39 wt%) and CaO(0.19 wt%-0.70 wt%). It is obviously enriched in LILEs such as Rb, Th and K,depleted in HFSEs such as Nb, Ti, La and Ce, with pronounced negative anomalies of Nb, Ti, P, Eu, Sr and Ba. Its Sr-Nd-Pb isotopic compositions show positive ε(t)(+0.72-+3.08), low T(805-997 Ma),and high radioactive Pb with(Pb/Pb)of 18.710-19.304,(Pb/Pb)of 15.557-15.604 and(Pb/Pb)of 37.887-38.330. Petrological characteristics and geochemical data suggest that the alkalifeldspar granite in the Hongol area belongs to aluminous A-type granite. This A-type granite formed in a post-collisional extensional setting and was generated by the partial melting of felsic rocks in the middlelower crust resulting from post-collisional slab breakoff. It is suggested that the Paleo-Asian Ocean was closed before the Permian in central Inner Mongolia.

关键词： aluminous A-type granite zircon U-Pb dating petrogenesis slab breakoff Xing'an Mongolian Orogenic Belt China

Organometal halide perovskite quantum dots:synthesis,optical properties,and display applications

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2016年第8期27卷 1124-1130,1464页

作者： gao-Ling Yang Hai-Zheng Zhong Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems School of Materials Science & Engineering

In recent two years,organometal halide perovskites quantum dots are emerging as a new member of the nanocrystals *** the chemical point of view,these perovskites quantum dots can be synthesized either by classical hot-injection technique for inorganic semiconductor quantum dots or the reprecipitation synthesis at room temperature for organic *** a physical point of view,the observed large exciton binding energy,well self-passivated surface,as well as the enhanced nonlinear properties have been of great interest for fundamental *** the application point of view,these perovskites quantum dots exhibit high photoluminescence quantum yields,wide wavelength tunability and ultra-narrow band emissions,the combination of these superior optical properties and low cost fabrication makes them to be suitable candidates for display *** this short review,we introduce the synthesis,optical properties,the prototype light-emitting devices,and the current important research tasks of halide perovsktie quantum dots,with an emphasis on CH_3NH_3PbX_3（X= CI,Br,I） quantum dots that developed in our group.

关键词： Halide perovskite Quantum dots Photoluminescence Electroluminescence Display

Investigation of the Mei-yu Front Using a New Deformation Frontogenesis Function

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2015年第5期32卷 635-647页

作者： YANG Shuai gao Shouting Chungu LU Laboratory of Cloud-Precipitation Physics and Severe Storms Institute of Atmospheric PhysicsChinese Academy of Sciences State Key Laboratory of Severe Weather Chinese Academy of Meteorological Sciences U.S. National Science Foundation

A new frontogenesis function is developed and analyzed on the basis of a local change rate of the absolute horizontal gradient of the resultant deformation. Different from the traditional frontogenesis function, the newly defined deformation frontogenesis is derived from the viewpoint of dynamics rather than thermodynamics. Thus, it is more intuitive for the study of frontogenesis because the compaction of isolines of both temperature and moisture can be directly induced by the change of a flow field. This new frontogenesis function is particularly useful for studying the mei-yu front in China because mei-yu rainbands typically consist of a much stronger moisture gradient than temperature gradient, and involve large deformation flow. An analysis of real mei-yu frontal rainfall events indicates that the deformation frontogenesis function works remarkably well, producing a clearer mei-yu front than the traditional frontogenesis function based on a measure of the potential temperature gradient. More importantly, the deformation frontogenesis shows close correlation with the subsequent（6 h later） precipitation pattern and covers the rainband well, bearing significance for the prognosis or even prediction of future precipitation.

关键词： deformation frontogenesis precipitation

Speed Distributions of CMEs in Cycle 23 at Low and High Latitudes

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Astronomy and Astrophysics 2008年第2期8卷 146-152页

作者： Peng-Xin gao Ke-Jun Li National Astronomical Observatories / yunnan Observatory Chinese Academy of Sciences Kunming 650011 GraduateSchool of Chinese Academy of Sciences Beijing 100049

We analyzed the speed （v） distributions of 11584 coronal mass ejections （CMEs） observed by the Large Angle and Spectrometric Coronagraph Experiment on board the Solar and Heliospheric Observatory （SOHO/LASCO） in cycle 23 from 1996 to 2006. We find that the speed distributions for high-latitude （HL） and low-latitude （LL） CME events are nearly identical and to a good approximation they can be fitted with a lognormal distribution. This finding implies that statistically the same driving mechanism of a nonlinear nature is acting in both HL and LL CME events, and CMEs are intrinsically associated with the source＇s magnetic structure on large spatial scales. Statistically, the HL CMEs are slightly slower than the LL CMEs. For HL and LL CME events respectively, the speed distributions for accelerating and decelerating events are nearly identical and also to a good approximation they can be both fitted with a lognormal distribution, thus supplementing the results obtained by yurchyshyn et al.

关键词： Sun activity -- Sun coronal mass ejections (CMEs)

Influence of Dissolved Oxygen on the Protectiveness and Morphological Characteristics of Calcareous Deposits with Galvanostatic Polarization

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2017年第2期16卷 243-248页

作者： LI Chengjie DU Min gao Rongjie The Key Laboratory of Marine Chemistry Theory and Technology Ministry of EducationCollege of Chemistry and Chemical EngineeringOcean University of ChinaQingdao 266100P.R.China

The influence of dissolved oxygen on calcareous deposits formed under galvanostatic polarization mode was *** the dissolved oxygen concentration was less than 7 mg L^(-1),the cathodic protection potential showed a plateau at the initial polarization,and then quickly shifted *** the dissolved oxygen was more than 9 mg L^(-1),the potential shifted negatively in a linear *** 168 h of polarization,the final protection potential shifted negatively with the decreasing dissolved oxygen *** deposition progress was monitored by electrochemical impedance spectroscopy,and only one single loop was found in Nyquist diagram,indicating deposits of ineffective protectiveness precipitation under the experimental *** protection factor of deposits increased with the decreasing dissolved oxygen concentration which was detected by linear polarization resistance *** cathodic electrochemical reaction could change very shortly from oxygen reduction to hydrogen evolution after cathodic protection under very low dissolved oxygen concentration,such as 1 mg L^(-1),resulting in the hydrogen bubbling from the metallic surface and the decrease of deposits protection *** by scanning electron microscopy and X-ray diffraction analysis demonstrated that the deposits were mainly of calcite under the experimental conditions,and that dissolved oxygen had no effect on the crystalline types of calcium carbonate.

关键词： seawater calcareous deposits dissolved oxygen galvanostatic cathodic protection

The Fabrication of Bio-ceramsite for the Removal of Heavy Metals and Its Toxicity to Bacteria

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2015年第3期30卷 649-654页

作者：石岩 SUN Ken 齐学斌 gao Qing Farmland Irrigation Research Institute Chinese Academy of Agricultural Sciences School of Environmental and Municipal Engineering North China University of Water Resources and Electric Power School of Water Resource & Environment China University of Geosciences

Bio-ceramsite technology is one of the most effective technologies in the pretreatment of drinking water. In this work, bio-ceramsite was fabricated by Citrobacterfreundii （C. freundii） immobilization on the ceramsite. The findings of the current study suggest that the bio-ceramites showed biosorption abilities for Cd（II） and Pb（II） and the removal efficiency for Pb（II） is lower than Cd（II）. The adsorption mechanism can be attributed to electrostatic attraction and covalent bond. The morphology of the cells changed after the adsorption of Cd（II） and Pb（II） due to the dissociation of the assembly of peptidoglycan and lipopolysaccharide. The fluorescence polarization has shown a significant decrease in membrane fluidity and an increase of permeability of cell membrane. The spectral profile of C. freundii suggests the alteration of carbonyl, amide and phosphonic groups on the cell membrane.

关键词： immobilization biosorption bio-ceramsite dissociation cell membrane

Assessment of toxicity of two nitroaromatic compounds in the freshwater fish Cyprinus carpio

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2012年第4期6卷 518-523页

作者： Hongyan SHEN Jixi gao Jinsheng WANG College of Water Science Beijing Normal UniversityBeijing 100875China School of Environmental Science and Engineering Hebei University of Science and TechnologyShijiazhuang 050018China Nanjing Institute of Environmental Sciences SEPANanjing 210042China

This study was conducted to evaluate the toxicological response ofp-nitrotoluene and p-nitroaniline to the key fish species, Cyprinus carpio. A freshwater fish bioassay based on the 96 h LC50 was used to estimate the single and joint toxicity of the two chemicals. The toxicity of p-nitrotoluene was greater than that of pnitroaniline based on 96 h LCso values of 40.74 mg.L^-1 and 48.99mg.L^-1, respectively. Both compounds had moderate toxicity toward Cyprinus carpio, and this toxicity increased with the exposure duration and con- centration. Binary mixtures of the compounds were more toxic than the individual compounds at 96 h, and they acted upon partial addition. When the exposure time was longer, the toxicity increased for mixtures of compounds with the same concentration or toxicity. The results of this study suggest that exposure to a combination of these chemicals would result in a higher environmental risk in aquatic systems than exposure to either compound alone. Further research is needed to investigate the combined effects and sublethal toxicity of p-nitrotoluene and p- nitroaniline, since they are both still used in China.

关键词： joint toxicity Cyprinus carpio LC50 pnitrotoluene p-nitroaniline toxic unit

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

Science China Mathematics 2024年第2期67卷 405-430页

作者： Junzhuo gao Lei Wang Heng Lian School of Statistics and Data Science&LPMC Nankai UniversityTianjin 300071China Department of Mathematics City University of Hong KongHong KongChina

In this paper, we consider the unified optimal subsampling estimation and inference on the lowdimensional parameter of main interest in the presence of the nuisance parameter for low/high-dimensionalgeneralized linear models (GLMs) with massive data. We first present a general subsampling decorrelated scorefunction to reduce the influence of the less accurate nuisance parameter estimation with the slow convergencerate. The consistency and asymptotic normality of the resultant subsample estimator from a general decorrelatedscore subsampling algorithm are established, and two optimal subsampling probabilities are derived under theA- and L-optimality criteria to downsize the data volume and reduce the computational burden. The proposedoptimal subsampling probabilities provably improve the asymptotic efficiency of the subsampling schemes in thelow-dimensional GLMs and perform better than the uniform subsampling scheme in the high-dimensional GLMs.A two-step algorithm is further proposed to implement, and the asymptotic properties of the correspondingestimators are also given. Simulations show satisfactory performance of the proposed estimators, and twoapplications to census income and Fashion-MNIST datasets also demonstrate its practical applicability.

关键词： A-optimality decorrelated score subsampling high-dimensional inference L-optimality massive data

Simple Harish-Chandra supermodules over the super Schrdinger algebra

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2015年第12期58卷 2477-2488页

作者： CAI YanAn gao yun WANG YongJie School of Mathematical Sciences University of Science and Technology of China Department of Mathematics and Statistics York University

We study the N=1 super Schrdinger algebra S in(1+1)-dimensional spacetime. The first part of this paper determines the necessary and sufficient conditions for highest weight supermodules over S to be simple. The paper also describes the structure of all Verma supermodules and determines all simple Harish-Chandra supermodules over S.

关键词： super Schrodinger algebra weight supermodule simple supermodule Harish-Chandra supermodules