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The effects of DDT on the feeding, respiration, survival, and reproduction of Sinocalanus tenellus(Copepoda:Calanoida)

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Acta Oceanologica Sinica 2014年第9期33卷 133-138页

作者： XU Donghui liu Guangxing College of Physical and Environmental Oceanography Ocean University of China College of Environmental Science and Engineering Ocean University of China Key Laboratory of Marine Environment & Ecology Ministry of Education Ocean University of China

DDT （dichloro-diphenyl-trichloroethane） as a type of organochlorine pesticides, is an important compo nent of pesticides pollution whose impact on the marine ecosystem is urgently to be evaluated. To investi gate the biological effects of DDT on the marine ecosystem, copepods being the main contributor of sec ondary productivity in the marine ecosystem, were selected as target animals. The influence of DDT on the feeding, respiration, survival, and reproduction of Sinocalanus tenellus （S. tenellus） was analyzed and the antioxidant enzymes activities in the individuals were measured under different exposure concentrations of DDT. The 48 h median lethal concentration （LC50） and 96 h LC50 of DDT to S. tenellus were 5.44 and 2.50 pg/dma, respectively. The filtration rates, grazing rates, and respiration of S. tenellus decreased apparently with increased DDT concentrations. Under lower concentration （〈625 ng/dm3） of DDT, the activities of the antioxidant enzymes, including superoxide dismutase and catalase in the animals increased significantly compared with those in the animals without any exposure to DDT, which suggested that the antioxidant enzymes can protect the animals from oxidative damage. However, the activity of the antioxidant enzyme decreased when the animals were exposed to higher concentration （1250-2 500 ng/dma） of DDT. The sur-vival rate of both females and males was reduced when they were exposed to DDT less than 250 ng/dm3, but females showed higher survival rate than males when they are under the same concentration. The hatching ratio and the egg diameters of S. tenellus decreased significantly when they were exposed to DDT with a concentration of 25 and 250 ng/dm3, however, the cumulative egg production did not show any significant variation when the animals were exposed to the above DDT concentration. These data in the preset study suggested that exposure to DDT can cause the variation of the species composition of copepods, and further affect the ma

关键词： DDT Sinocalanus tenellus survival reproduction feeding respiration antioxidant enzyme

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Delineating nuclear reprogramming

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Protein & Cell 2012年第5期3卷 329-345页

作者： Jolene Ooi Pentao liu Wellcome Trust Sanger Institute Hinxton CB101SAUnited Kingdom Agency for Science Technology and ResearchSingapore 138632Singapore

Nuclear reprogramming is described as a molecular switch,triggered by the conversion of one cell type to *** key experiments in the past century have provided insight into the field of nuclear *** deemed impossible,this re-search area is now brimming with new findings and *** this review,we aim to give a historical perspective on how the notion of nuclear reprogram-ming was established,describing main experiments that were performed,including(1)somatic cell nuclear transfer,(2)exposure to cell extracts and cell fusion,and(3)transcription factor induced lineage ***,we focus on(4)transcription factor induced pluripotency,as initiated by a landmark discovery in 2006,where the process of converting somatic cells to a pluripotent state was narrowed down to four tran-scription *** conception that somatic cells possess the capacity to revert to an immature status brings about huge clinical implications including per-sonalized therapy,drug screening and disease *** this technology has potential to revolu-tionize the medical field,it is still impeded by technical and biological *** review describes the effervescent changes in this field,addresses bottle-necks hindering its advancement and in conclusion,applies the latest findings to overcome these issues.

关键词： nuclear reprogramming naïve pluripotency

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Short-term Photovoltaic Power Forecasting Using SOM-based Regional Modelling Methods

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Chinese Journal of Electrical Engineering 2023年第1期9卷 158-176页

作者： Jun Li Qibo liu School of Automation and Electrical Engineering Lanzhou Jiaotong UniversityLanzhou 730070China

The inherent intermittency and uncertainty of photovoltaic(PV)power generation impede the development of grid-connected PV *** forecasting PV output power is an effective way to address this problem.A hybrid forecasting model that combines the clustering of a trained self-organizing map(SOM)network and an optimized kernel extreme learning machine(KELM)method to improve the accuracy of short-term PV power generation forecasting are ***,pure SOM is employed to complete the initial partitions of the training dataset;then the fuzzy c-means(FCM)algorithm is used to cluster the trained SOM network and the Davies-Bouldin index(DBI)is utilized to determine the optimal size of clusters,***,in each data partition,the clusters are combined with the KELM method optimized by differential evolution algorithm to establish a regional KELM model or combined with multiple linear regression(MR)using least squares to complete coefficient evaluation to establish a regional MR *** proposed models are applied to one-hour-ahead PV power forecasting instances in three different solar power plants provided by *** with other single global models,the root mean square errors(RMSEs)of the proposed regional KELM model are reduced by 52.06%in plant 1,54.56%in plant 2,and 51.43%in plant 3 on *** results demonstrate that the forecasting accuracy has been significantly improved using the proposed *** addition,the comparisons between the proposed and existing state-of-the-art forecasting methods presented have demonstrated the superiority of the proposed *** forecasts of different methods in different seasons revealed the strong robustness of the proposed *** four seasons,the MAEs and RMSEs of the proposed SF-KELM are generally the ***,the R2 value exceeds 0.9,which is the closest to 1.

关键词： Photovoltaic power generation forecasting self-organizing map regional modeling extreme learning machine

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The triphibious warfare against viruses

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Science China(Life Sciences) 2017年第12期60卷 1295-1298页

作者： William J.liu Di liu Key Laboratory of Medical Virology and Viral Diseases Ministry of Health of People's Republic of China National Institute for Viral Disease Control and Prevention Chinese Center for Disease Control and Prevention CAS Key Laboratory for Pathogenic Microbiology and Immunology Institute of Microbiology Chinese Academy of Sciences Computational Virology Group CAS Key Laboratory of Special Pathogens and Biosafety Wuhan Institute of Virology Chinese Academy of Sciences

Despite the long journey undertaken by mankind to confront the diseases caused by viruses,people were unaware of the existence of viruses until the closing years of the 19th century,when the Russian biologist Dmitri Ivanovsky demonstrated that tobacco plants could be infected by a toxin smaller than bacteria,followed by which the Dutch microbiologist Martinus Beijerinck termed the toxin as a contagium vivum fluidum （soluble living germ） and re-introduced the word ＂virus＂（derived from the Latin word ＂virus＂ meaning poison; the modern meaning is an ＂agent that causes infectious disease＂ that was first recorded in 1728）.

关键词： The triphibious warfare viruses

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Numerical simulation of the EM scattering and Doppler spectrum of a low flying target above dynamic oceanic surface by using the FEMDDM method

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Science China(Physics,Mechanics & Astronomy) 2004年第5期47卷 597-611页

作者： liu Peng JIN Yaqiu Key Laboratory of Wave Scattering and Remote Sensing Information Ministry of Education Fudan University Shanghai 200433 China Key Laboratory of Wave Scattering and Remote Sensing Information Ministry of Education Fudan University Shanghai 200433 China

To study the Doppler (DP) spectrum of a flying target above the dynamic oceanic surface, a two-level quasi-stationary algorithm (TLQSA) of the finite element method (FEM) with domain decomposition (DDM) is developed. The DP spectrum of a fast-moving target requires a small time-sampling rate. At most time steps, scattering from the flying target is solved by the FEM solution in only one sub-domain; meanwhile the interactions between the target and rough sea surface in other sub-domains are obtained by solving the global DDM coupling matrices. The slowly moving sea surface is evolved at a larger time step and the DP of oceanic clutter is obtained through all-subdomain FEM calculation. Numerical simulations of the DP spectrum from a target flying above the dynamic oceanic surface with and without a ship presence are obtained. The functional dependence of the DP spectrum in both the time and frequency domains upon the sea surface wind speed, target altitude, observation angle etc. are demon- strated and discussed.

关键词： Doppler spectrum, rough surface and target, electromagnetic scattering, domain decomposition method, finite element method.

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The Classification of Proper Holomorphic Mappings Between Special Hartogs Triangles of Different Dimensions

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Chinese Annals of Mathematics,Series B 2008年第5期29卷 557-566页

作者： Zhihua CHEN Yang liu Department of Mathematics Tongji University Shanghai 200092 China Department of Mathematics Zhejiang Normal University Jinhua 321004 Zhejiang China

The authors discuss the proper holomorphic mappings between special Hartogs triangles of different dimensions and obtain a corresponding classification theorem.

关键词： Proper holomorphic mapping Hartogs triangle Automorphism group

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Long-lasting photoluminescence quantum yield of cesium lead halide perovskite-type quantum dots

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Frontiers of Chemical Science and Engineering 2021年第1期15卷 187-197页

作者： Yonghyun Kim Huiwen liu Yi liu Boa Jin Hao Zhang Wenjing Tian Chan Im Department of Chemistry Konkuk UniversitySeoul 05029Korea State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchun 130012China

Cesium lead halide perovskite(CsPbX_(3),X=Cl,Br,I)quantum dots(QDs)and their partly Mn^(2+)-substituted QDs(CsPb1–xMnxX3)attract considerable attention owing to their unique photoluminescence(PL)*** two types of QDs,having different PL decay dynamics,needed to be further investigated in a form of aggregates to understand their solid-state-induced exciton dynamics in conjunction with their behaviors upon degradation to achieve practical applications of those promising ***,thus far,these QDs have not been sufficiently investigated to obtain deep insights related to the long-term stability of their PL properties as aggregated ***,in this study,we comparatively examined CsPbX_(3)-and CsPb1–xMnxX_(3)-type QDs stocked for>50 d under dark ambient conditions by using excitation wavelength-dependent PL quantum yield and time-resolved PL *** investigations were performed with powder samples in addition to solutions to determine the influence of the inter-QD interaction of the aged QD aggregates on their radiative *** turns out that the Mn^(2+)-substituted QDs exhibited long-lasting PL quantum efficiencies,while the unsubstituted CsPbX_(3)-type QDs exhibited a drastic reduction of their PL *** the obtained PL traces were clearly sensitive to the sample *** is discussed with the possible interaction depending on the size and distance of the QD aggregates.

关键词： quantum dots cesium lead halide perovskite time-resolved photoluminescence PL quantum yield QD aggregates

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Counting Multiplicities in a Hypersurface over Number Fields

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Algebra Colloquium 2018年第3期25卷 437-458页

作者： Hao Wen Chunhui liu Department of iVlathematicM Sciences Tsinghua University Beijing 100084 China Department of Mathematics Faculty of Science Kyoto University Kyoto 606-8502 Japan

We fix a counting function of multiplicities of algebraic points in a projective hypersurface over a number field, and take the sum over all algebraic points of bounded height and fixed degree. An upper bound for the sum with respect to this counting function will be given in terms of the degree of the hypersurface, the dimension of the singular locus, the upper bounds of height, and the degree of the field of definition.

关键词： algebraic point counting multiplicities height function over projective space intersection tree rational point

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Response of soil water dynamics to precipitation years under different vegetation types on the northern Loess Plateau, China

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Journal of Arid Land 2016年第1期8卷 47-59页

作者： liu Bingxia SHAO Ming'an State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationChinese Academy of Sciences and Ministry of Water Resources Key Laboratory of Agricultural Water Resources Center for Agricultural Resources Research Institute of Genetics and Developmental Biology Chinese Academy of Sciences State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Northwest A&F University

Implementation of the Grain-for-Green project has led to rapid land cover changes and resulted in a significantly increased vegetation cover on the Loess Plateau of China during the past few decades. The main objective of this study was to examine the responses of soil water dynamics under four typical vegetation types against precipitation years. Soil water contents (SWCs) were measured in 0–4.0 m profiles on a hillslope under the four vegetation types of shrub, pasture, natural fallow and crop in a re-vegetated catchment area from April to October in normal (2010), dry (2011), wet (2014) and extremely wet (2013) years. The results indicated that precipitation and vegetation types jointly controlled the soil water temporal dynamics and profile characteristics in the study region. SWCs in 0–4.0 m profiles of the four vegetation types were ranked from high to low as crop>fallow>pasture>shrub and this pattern displayed a temporal stability over the four years. In the extremely wet year, SWC changes occurred in the 0–2.0 m layer under shrub and pasture while the changes further extended to the depth of 4.0-m deep layers under fallow and crop. In the other three years, SWCs changes mainly occurred in the 0–1.0 m layer and kept relatively stable in the layers deeper than 1.0 m for all the four vegetation types. The interannual variation in soil depth of SWCs was about 0–2.0 m for shrub and pasture, about 0–3.4 m for fallow and about 0–4.0 m for crop, respectively. The dried soil layers formed at the depths of 1.0, 0.6, 1.6 and 0.7 m under shrub, and 1.0, 1.0, 2.0 and 0.9 m under pasture, respectively in 2010, 2011, 2013 and 2014. The infiltrated rainwater mostly stayed in the 0–1.0 m layer and hardly supplied to soil depth >1.0 m in normal, dry and wet years. Even in the extremely wet year of 2013, rainwater recharge depth did not exceed 2.0 m under shrub and pasture. This implied that soil desiccation was difficult to remove in normal, dry and wet years, and soil desicc

关键词： precipitation pattern restoration soil water dynamics soil desiccation vegetation type

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Numerical simulation of radio signal from extended air showers

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Research in Astronomy and Astrophysics 2015年第5期15卷 623-645页

作者： Wei liu Xuelei Chen National Astronomical Observatories Chinese Academy of Science University of Chinese Academy of Sciences Center of High Energy Physics Peking University

The burst of radio emission by an extensive air shower provides a promising alternative for detecting ultra-high energy cosmic rays. We have developed an inde- pendent numerical program to simulate these radio signals. Our code is based on a microscopic treatment, with both the geosynchrotron radiation and charge included. Here we give the first presentation of our basic program and its results. When the time-domain signals for different polarizations are computed, we find that the pulses take on a bipolar pattern and the spectrum is suppressed towards the lower frequencies. We investigate how showers at different heights in the atmosphere contribute to the total signal, and examine the signal strength and distribution at sites with different elevations. We also study the signal from showers with different inclination angles and azimuth directions. In all these cases we find the charge excess effect is important.

关键词： astroparticle physics -- radiation mechanisms general

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