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Studies on Lead Tungstate Crystal

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Chinese Physics Letters 1998年第1期15卷 46-47页

作者： LIU feng-zhen han jian-ru MAN Chang-feng CHEN Huan-chu HE Mao Department of Physics Shandong UniversityJi’nan 250100 Institute of Crystal Materials Shandong UniversityJi’nan 250100

The growth of lead tungstate(PWO)single crystals and their luminescence properties such as light yield,scintillation decay time,and transmittance were *** colourless PWO single crystal has been obtained by using the presyntheses ***,Nb,and Mg ions were doped in the crystals and the Ba-doped crystal has a relatively short decay *** crystal was found having a better transmission spectrum than that of unannealed one.

关键词： crystal decay annealed

Gravitational Equivalence Theorem and Double-Copy for Kaluza-Klein Graviton Scattering Amplitudes

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Research 2022年第4期2022卷 411-420页

作者： Yan-feng hang Hong-jian He Tsung-Dao Lee Institute and School of Physics and Astronomy Key Laboratory for Particle Astrophysics and Cosmology(MOE)Shanghai Key Laboratory for Particle Physics and CosmologyShanghai Jiao Tong UniversityShanghaiChina Institute of Modern Physics and Department of Physics Tsinghua UniversityBeijingChina Center for High Energy Physics Peking UniversityBeijingChina

We analyze the structure of scattering amplitudes of the Kaluza-Klein (KK) gravitons and of the KK gravitational Goldstone bosons in the compactified 5d general relativity (GR). Using a general Rξ gauge fixing, we study the geometric Higgs mechanism for the massive spin-2 KK gravitons. We newly propose and prove a gravitational equivalence theorem (GRET) to connect the scattering amplitudes of longitudinal KK gravitons to that of the KK gravitational Goldstone bosons, which formulates the geometric gravitational Higgs mechanism at the scatteringS-matrix level. We demonstrate that the GRET provides a general energy cancellation mechanism guaranteeing the N-point longitudinal KK graviton scattering amplitudes to have their leading energy dependence cancelled down by a large power factor of E^(2N)(N≥4) up to any loop level. We propose an improved double-copy approach to construct the massive KK graviton (Goldstone) amplitudes from the KK gauge boson (Goldstone) amplitudes. With these, we establish a new correspondence between the two types of energy cancellations in the four-point longitudinal KK amplitudes at tree level: E^(4)→E0 in the KK gauge theory and E^(10)→E^(2) in the KK GR theory.

关键词： theory gauge guarantee

Accumulation and distribution of arsenic and cadmium by tea plants

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2008年第3期9卷 265-270页

作者： Yuan-zhi SHI jian-yun RUAN Li-feng MA Wen-yan han Fang WANG Tea Research Institute Chinese Academy of Agricultural Sciences Hangzhou 310008 China

It is important to research the rules about accumulation and distribution of arsenic and cadmium by tea plants,which will give us some scientific ideas about how to control the contents of arsenic and cadmium in *** this study,by field investigation and pot trial,we found that mobility of arsenic and cadmium in tea plants was *** arsenic and cadmium absorbed were fixed in feeding roots and only small amount was transported to the above-ground *** of arsenic and cadmium,based on their concentrations of unit dry matter,in tea plants grown on un-contaminated soil was in the order:feeding roots>stems≈main roots>old leaves>young *** tea plants were grown on polluted soils simulated by adding salts of these two metals,feeding roots possibly acted as a buffer and defense,and arsenic and cadmium were transported less to the aboveground *** concentration of cadmium in soil significantly and negatively correlated with chlorophyll content,photosynthetic rate,transpiration rate and biomass production of tea plants.

关键词： Tea plant Arsenic (As) Cadmium (Cd) Absorption Accumulation

Identification of Sphaeroma terebrans via morphology and the mitochondrial cytochrome c oxidase subunit I (COI) gene

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Zoological Research 2016年第5期37卷 307-312页

作者： Xiu-feng LI Chong han Cai-Rong ZHONG Jun-Qiu XU jian-Rong HUANG School of Life Sciences Sun Yat-Sen University Guangzhou 510275 China Management Bureau of Dongzhaigang Mangrove Natural Reserve Haikou 571129 China

Sphaeroma terebrans, a wood-boring isopoda, is distributed worldwide in tropical and subtropical mangroves. The taxonomy of S. terebrans is usually based on morphological characteristics, with its molecular identification still poorly understood. The number of teeth on the uropodal exopod and the length of the propodus of the seventh pereopod are considered as the major morphological characteristics in S. terebrans, which can cause difficulty in regards to accurate identification. In this study, we identified S. terebrans via molecular and morphological data. Furthermore, the validity of the mitochondrial cytochrome c oxidase subunit I （COl） gene as a DNA barcode for the identification of genus Sphaeroma, including species S. terebrans, S. retrolaeve, and S. serratum, was examined. The mitochondrial COl gene sequences of all specimens were sequenced and analysed. The interspecific Kimura 2-parameter distances were higher than intraspecific distances and no intraspecificinterspecific distance overlaps were observed. In addition, genetic distance and nucleotide diversity （TT） exhibited no differences within S. terebrans. Our results revealed that the mitochondrial COl gene can serve as a valid DNA barcode for the identification of S. terebrans. Furthermore, the number of teeth on the uropodal exopod and the length of the propodus of the seventh pereopod were found to be unreliable taxonomic characteristics for S. terebrans.

关键词： Sphaeroma terebrans DNA barcode COl gene Molecular identification

Cerebral microvascular dysfunction and neurodegeneration in dementia

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Stroke & Vascular Neurology 2019年第2期4卷 105-107页

作者： feng han Key Laboratory of Cardiovascular and Cerebrovascular Medicine School of PharmacyNanjing Medical UniversityNanjingJiangsuChina

Maintaining normal learning and memory functions requires a high degree of coordination between neural and vascular *** and clinical studies have shown that brain microvasculature dysfunction activates inflammatory cells in the brain,leading to progressive neuronal loss and eventually *** review focuses on recent studies aimed at identifying the molecular events that link cerebral microvascular dysfunction to neurodegeneration,including oxidative/nitrosative stress,cellular metabolic dysfunction,inflammatory signalling and abnormal synaptic plasticity.A better understanding of the coupling between vasculature and brain neurons and how this coupling is disrupted under pathological conditions is of great significance in identifying new diagnostic and treatment targets for dementia for which no new drugs have been approved since 2003.

关键词： dysfunction drugs eventually

Green Chemical Engineering

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Engineering 2017年第3期3卷 283-284页

作者： jian-feng Chen State Key Laboratory of Organic-lnorganic Composites College of Chemical Engineering Beifing University of Chemical Technology Beijing 100029 China

1. Introduction Green chemical engineering is regarded as one of the most effi- cient means of achieving sustainable development in chemical in- dustrial processes. It can be divided into two main categories： Green product engineering. Examples include the develop- ment of new catalysts and the development and use of renewa- ble resources （e.g., solar energy and biomass）.

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Study of electrospray ionization tandem mass spectrometry of the benzofuranone compounds

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Chinese Chemical Letters 2008年第3期19卷 324-328页

作者： Zhan Qi Niu Yu Min Sun feng Niu jian han Da Wei Chen School of Pharmacy of Shenyang Pharmaceutical University Shenyang 110016 China ShiJiaZhuang Pharnta Group NBP Pharmaceutical Co. Ltd. Shijiazhuang 052160 China Department of Pharmaceutical Engineering School of Chemical EngineeringDalian University of Technology Dalian 116000 China Department of Natural Medicines School of Pharmaceutical Sciences Peking Universio Health Science Center Beijing 10008.3 China

A detailed analysis of benzofuranone compounds under multiple tandem mass spectrometry （ESI-MS^n） conditions is reported. Element composition data of the fragment ions were obtained with the aid of comparison of the multiple tandem mass spectra of four compounds, and the structures of which are identical except for some substituted groups or epimers or cis-trans-isomers. Attempts have been made to provide rational pathways for the formation of the fragment ions from these protonated compounds. And the structure-fragmentation relationships will facilitate the characterization of the structures of other analogs.

关键词： ESI-MS^n Benzofuranones Epimer: cis-trans-Isomer

Non-equilibrium turbulent phenomena in transitional flat plate boundary-layer flows

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Applied Mathematics and Mechanics(English Edition) 2021年第4期42卷 567-582页

作者： feng LIU Le FANG jian FANG School of Energy and Power Engineering North University of ChinaTaiyuan 030051China Laboratory of Mathematics and Physics Ecole Centrale de P′ekinBeihang UniversityBeijing 100191China Scientific Computing Department STFC Daresbury LaboratoryWarrington WA44ADU.K.

Many recent laboratory experiments and numerical simulations support a non-equilibrium dissipation scaling in decaying turbulence before it reaches an equilibrium *** analyzing a direct numerical simulation(DNS)database of a transitional boundary-layer flow,we show that the transition region and the non-equilibrium turbulence region,which are located in different streamwise zones,present different non-equilibrium ***,in the wall-normal direction,the viscous sublayer,log layer,and outer layer show different non-equilibrium phenomena which differ from those in grid-generated turbulence and transitional channel *** findings are expected to shed light on the modelling of various types of non-equilibrium turbulent flows.

关键词： non-equilibrium turbulence flat plate boundary layer turbulence model

Study on hydrochemical characteristics and formation mechanism of shallow groundwater in eastern Songnen Plain

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Journal of Groundwater Science and Engineering 2018年第3期6卷 161-170页

作者： LI Xiao-han WANG Rui LI jian-feng Institute of Hydrogeology and Environmental Geology Chinese Academy of Geological SciencesShijiazhuang 050061China Team of Groundwater Resource Evaluation and Protection Shijiazhuang 050061China School of Water Resources and Environment Hebei GEO UniversityShijiazhuang 050031China Hebei Province Key Laboratory of Sustained Utilization and Development of Water Resources Shijiazhuang 050031China

Under the influence of global climate changes and human activities, the Songnen Plain's groundwater environment is deteriorating, which becomes an important factor restricting the social economic development and ecological balance. As a relatively independent water system in the Songnen Plain, the groundwater system of the Songhua River provides the main water sources for industry, agriculture, life and other aspects. According to the hydrogeological investigation, groundwater sample collection and testing in the eastern Songnen Plain, descriptive statistics analysis, piper diagram, Gibbs diagram and reverse hydrogeochemical simulation were used to analyze the hydrochemical characteristics and evolution laws of regional groundwater. The results of this study show that HCO_3^- and Ca^(2+) are the main anion and cation in the groundwater; the formation of groundwater chemical components are controlled by topographic and geomorphic factors and groundwater occurrence conditions; groundwater subarea of the Lalin-Ashi River is mainly controlled by weathering-dissolution process, and evaporation and ion-exchange reactions are more obvious in groundwater subarea of the Hulan-Tongken River, whose chemical composition also affects the valley plain groundwater subarea in the discharge area; in addition, local high intensity withdrawal causes abnormal hydrochemical evolution processes. The research results can offer scientific basis for rational utilization and protection of groundwater.

关键词： The Songnen Plain Groundwater Hydrochemical characteristics Hydrogeochemical modeling Formation