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Environmental characteristics of sandstorm of minqin Oasis in China for recent 50 years

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Journal of Environmental Sciences 2005年第5期17卷 857-860页

作者： ZHANG Ke-cun qu Jian-jun ZU Rui-ping FANG Hai-yan Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research Institute. Chinese Academy ofSciences Lanzhou 730000 China

The purpose of this present study is to investigate the frequency and variation of sandstorm in minqin Oasis. Using daily observational data of sandstorm and other meteorologic data from 1954 to 2000, we have illuminated the relationship between sandstorm, meteorological parameters and human activities. The results of the analysis show that the highest frequency of sandstorms occurrence and their duration mainly focus on March, April and May, especially in April. Most of sandstorms occur from midday to nightfall, but relative few appear from midnight to forenoon, which apparently correlates to the daily variations of atmospheric thermal stability within atmospheric boundary layer. Monthly mean and annual mean duration of sandstorms coincide well with the frequencies of sandstorm occurrence.

关键词： minqin Oasis sandstorm environmental characteristics

Coronavirus disease 2019(COVID-19):a clinical update

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Frontiers of Medicine 2020年第2期14卷 126-135页

作者： min Zhou Xinxin Zhang Jieming qu National Research Center for Translational Medicine Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghai 200025China Department of Respiratory and Critical Care Medicine Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghai 200025China Institute of Respiratory Diseases Shanghai Jiao Tong University School of MedicineShanghai 200025China Research Laboratory of Clinical Virology Ruijin Hospital and Ruijin Hospital North Affiliated to Shanghai Jiao Tong University School of MedicineShanghai 200025China

Coronavirus disease 2019(COVID-19)caused by severe acute respiratory syndrome coronavirus-2(SARS-CoV-2)has posed a significant threat to global *** caused a total of 80868 confirmed cases and 3101 deaths in Chinese mainland until March 8,*** novel virus spread mainly through respiratory droplets and close *** disease progressed,a series of complications tend to develop,especially in critically ill *** findings showed representative features of acute respiratory distress syndrome and involvement of multiple *** from supportive care,no specific treatment has been established for *** efficacy of some promising antivirals,convalescent plasma transfusion,and tocilizumab needs to be investigated by ongoing clinical trials.

关键词： coronavirus disease 2019 epidemiology pathology radiology clinical characteristics treatment

Applicability of discrete element method with spherical and clumped particles for constitutive study of granular materials

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第1期14卷 240-251页

作者： Tongming qu min Wang Yuntian Feng Zienkiewicz Centre for Computational Engineering College of EngineeringSwansea UniversitySwanseaWales SA18EPUK T-3 Fluid Dynamics and Solid Mechanics Group Theoretical DivisionLos Alamos National LaboratoryLos AlamosNM87545USA

Discrete element method(DEM)has been intensively used to study the constitutive behaviour of granular ***,to what extent a real granular material can be reproduced by virtual DEM simulations remains *** study attempts to answer this question by comparing DEM simulations with typical features of experimental granular *** groups of models with spherical and clumped particles are investigated from four perspectives:(i)deviatoric stress and volumetric behaviour;(ii)critical state behaviour;(iii)stress-dilatancy relationship;and(iv)the evolution of principal stress ratio against axial *** results demonstrate that DEM with spherical or clumped particles is capable of qualitatively describing macroscopic deviatoric stress responses,volumetric behaviour,and critical state behaviour observed in experiments for granular *** the other hand,some qualitative deviations between experiments and the investigated DEM simulations are also observed,in terms of the stress-dilatancy behaviour and principal stress ratio against axial strain,which are proven to be critical for constitutive *** results demonstrate that DEM with spherical or clumped particles may not necessarily fully capture experimental features of granular materials even from a qualitative *** is thus encouraged to thoroughly validate DEM with experiments when developing constitutive models based on DEM observations.

关键词： Discrete element method(DEM) Granular materials Constitutive behaviour Deviatoric hardening model Rolling resistance model Irregular particles

基于韭UPLC-HESI-MS/MS法的菜坪2号烟叶代谢特征分析

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西南农业学报 2023年第12期36卷 2678-2684页

作者：申树林刘涛邹焱顾怀康何轶尹能文孙夫军曹廷茂喻奇伟陈秀娥李成李彩斌曲存民西南大学农学与生物科技学院重庆400716 西南大学现代农业科学研究院重庆400716 贵州省烟草公司毕节市公司贵州毕节551700 贵州省烟草科学研究院贵阳550000 湖南中烟工业有限责任公司长沙410019

【目的】探究毕节市烟草公司选育的地方烤烟品种韭菜坪2号与对照品种云烟87在毕节地区种植的代谢差异,为后续揭示韭菜坪2号烟叶香型风格特征的分子机理奠定基础,同时为该品种的推广应用提供理论依据。【方法】以云烟87为对照材料,采用... 详细信息

【目的】探究毕节市烟草公司选育的地方烤烟品种韭菜坪2号与对照品种云烟87在毕节地区种植的代谢差异,为后续揭示韭菜坪2号烟叶香型风格特征的分子机理奠定基础,同时为该品种的推广应用提供理论依据。【方法】以云烟87为对照材料,采用液相色谱-质谱联用技术,对毕节市赫章县3个烟叶产区(达依、可乐、铁匠)的云烟87与韭菜坪2号新鲜烟叶进行代谢组分析。【结果】在烟叶样本中共检测到1880个离子峰,主成分分析表明3个烟叶产区的韭菜坪2号与云烟87均具有显著的代谢差异。以差异倍数大于2,t检验的P可乐>铁匠。同时鉴定到46个离子峰在3个产区的韭菜坪2号中积累量升高,49个离子峰在3个产区的韭菜坪2号中积累量降低。进一步在韭菜坪2号积累量升高的离子中鉴定到1种类黄酮代谢物M_9637[木犀草素7-(6’-丙二酰糖苷)]。对2个烟叶品种进行酚酸、类黄酮的广泛靶向代谢分析发现,两种类黄酮物质(异属李素和槲皮素)在韭菜坪2号中具有积累量升高的趋势。对降烟碱与尼古丁的分析发现,两种代谢物在韭菜坪2号中均表现出积累量降低的趋势。【结论】对毕节市赫章县3个烟叶产区的韭菜坪2号和云烟87新鲜烟叶代谢组比较分析表明,韭菜坪2号烟叶中类黄酮代谢水平高于云烟87,烟碱类物质代谢水平低于云烟87。上述两类物质的积累差异可能是韭菜坪2号烟叶香型风格特征形成的基础。

关键词：韭菜坪2号烟叶代谢组次生代谢物类黄酮尼古丁

Neighbor Distinguishing Total Choice Number of Sparse Graphs via the Combinatorial Nullstellensatz

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Acta Mathematicae Applicatae Sinica 2016年第2期32卷 537-548页

作者： cun-quan qu Lai-hao DING Guang-hui WANG Gui-ying YAN School of Mathematics Shandong University Academy of Mathematics and Systems Science Chinese Academy of Sciences

Let G =（V, E） be a graph and Ф ： V tA E → {1, 2,..., k） be a total-k-coloring of G. Let f（v）（S（v）） denote the sum（set） of the color of vertex v and the colors of the edges incident with v. The total coloring Ф is called neighbor sum distinguishing if （f（u） ≠ f（v）） for each edge uv∈ E（G）. We say that Фis neighbor set distinguishing or adjacent vertex distinguishing if S（u） ≠ S（v） for each edge uv ∈ E（G）. For both problems, we have conjectures that such colorings exist for any graph G if k 〉 △（G）＋ 3. The maximum average degree of G is the maximum of the average degree of its non-empty subgraphs, which is denoted by mad （G）. In this paper, by using the Combinatorial Nullstellensatz and the discharging method, we prove that these two conjectures hold for sparse graphs in their list versions. More precisely, we prove that every graph G with maximum degree A（G） and maximum average degree mad（G） has ch＇＇∑（G）〈 △（G）＋ 3 （where ch＇＇∑（G） is the neighbor sum distinguishing total choice number of G） if there exists a pair （k, m） ∈ {（6, 4）, （5, 18/5）, （4, 16）} such that △（G）〉 k and mad （G）〈 m.

关键词： neighbor sum distinguishing total coloring Combinatorial Nullstellensatz neighbor sum distin-guishing total choice number

Ice-and-snow tourism and its sustainable development in China: A new perspective of poverty alleviation

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Advances in Climate Change Research 2021年第6期12卷 881-893页

作者： AN Hong-min XIAO cun-De TONG Yao FAN Jie State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing100875China Climate Change Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing100029China Yingkou Meteorological Bureau Yingkou110001China Key Laboratory of Regional Sustainable Development Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing100101China

The development of ice-and-snow tourism (IST) has great potential for poverty alleviation and is of great significance for promoting the sustainable development of alpine areas. However, little attention has been given to evaluating the suitability and potential of ice-and-snow tourism in poverty-stricken areas. Taking 832 poverty-stricken counties in China as samples, this study proposed an integrity suitability index (ISI) based on natural and socioeconomic factors to evaluate the suitability and potential of developing ice-and-snow tourism in poverty-stricken counties. The results showed that there are significant differences between the spatial distributions of the suitability of glacier- and ski-related tourism. The former is mainly distributed in the Qinghai‒Tibet Plateau, while the latter is distributed in low-altitude mountainous areas. Additionally, 36.0% of the total number of poverty-stricken counties have the potential to match medium-to high-level ISIs of ice-and-snow tourism, of which 2.5%, 32.9% and 0.2% are suitable for glacier excursions, ski sports and both, respectively. Furthermore, climate change and environmental protection are the main constraints on the development of ice-and-snow tourism and corresponding development strategies are proposed. This study can provide references for scientific planning and policy making regarding the sustainable development in poverty-stricken areas.

关键词： Ice-and-snow tourism Poverty alleviation Cryosphere service Sustainable development Ski tourism Glacier tourism

Microstructure and high-temperature properties of Fe-Ti-Cr-Mo-B-C-Y2O3 laser cladding coating

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Journal of Rare Earths 2020年第6期38卷 683-688页

作者： min Zhang Xinhong Wang Shushuai Liu Kaili qu School of Mechanical Engineering Shandong UniversityJinan 250061China School of Materials Science and Engineering Shandong UniversityJinan 250061China

Fe-based composite coatings were fabricated on 5 CrNiMo die steel by laser beam melting a precursor mixture of ferrotitanium,ferrochromium,ferromolybdenum,B4 C and Y2 O3 *** structure and properties of the coatings were studied by X-ray diffraction(XRD),scanning electron microscopy(SEM),energy-dispersive spectrometer(EDS),resistance furnace and high-temperature *** results show that(Ti,Mo)C particles with flower-like and(Ti,Mo)B2 with block-like shapes are in situ formed during laser *** faction of multiple ceramic particles increases with the increasing of Y2 *** cumulative oxidation mass of the coating with 2 wt% Y2 O3 is decreased by one-third than that of the coating without Y2 *** oxidation layer of the coating with Y2 O3 is getting ***,high temperature wear volume loss of the coating with 2 wt% Y2 O3 is about 40% that of the coating without Y2 *** coating with 2 wt% Y2 O3 shows a smoother wear scar and few flat grooves are observed after high temperature wear test.

关键词： Laser composite coatings Rare earth oxide High-temperature oxidation resistance High-temperature wear resistance

Calcium imaging in Arabidopsis pollen cells using G-CaMP5

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Journal of Integrative Plant Biology 2018年第9期60卷 897-906页

作者： min Diao Xiaolu qu Shanjin Huang Key Laboratory of Plant Molecular Physiology Institute of BotanyChinese Academy of SciencesBeijing 100093China Center for Plant Biology School of Life SciencesTsinghua UniversityBeijing 100084China University of Chinese Academy of Sciences Beijing 100049China

Calcium （Ca2 ＋） signaling has been implicated in poJ]en germination and pollen tube growth. To date, however, we still know very little about how exactly Ca2＋ signaling links to various physiological subcellular processes during pollen germination and pollen tube growth. Given that Ca2＋ signaling is tightly related to the cytosolic concentration and dynamics of Ca2＋, it is vital to trace the dynamic changes in Ca＋ levels in order to decode Ca2＋ signaling. Here, we demonstrate that G-CaMP5 serves well as an indicator for monitoring cytosolic Ca2＋ dynamics in pollen cells. Using this probe, we show that cytosolic Ca2＋ changes dramatically during pollen germination, and, as reported previously, Ca2＋ forms a tip-focused gradient in the pollen tube and undergoes oscillation in the tip region during pollen tube growth. In particular, using G-CaMP5 allowed us to capture the dynamic changes in the cytosolic Ca2＋ concentration （[Ca2＋ ]cyt） in pollen tubes in response to various exogenous treatments. Our data suggest that G-CaMP5 is a suitable probe for monitoring the dynamics of [Ca2＋ ]cyt in pollen cells.

关键词： Calcium imaging in Arabidopsis pollen cells using G-CaMP5 MP

Selective Laser Melting of In Situ TiB/Ti6Al4V Composites: Formability, Microstructure Evolution and Mechanical Performance

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Acta Metallurgica Sinica(English Letters) 2020年第6期33卷 774-788页

作者： Yue Su Shun-cun Luo Liang Meng Piao Gao Ze-min Wang Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China

In the present study, a series of in situ TiB/Ti6Al4V composites were fabricated using selective laser melting. The formability, microstructure evolution and mechanical properties of the as-built samples added with different contents of TiB2 were studied. It is found that the densification level is related to both the content of TiB2 and laser energy density. The added TiB2 reinforcement particle can spontaneously react with titanium and then form the TiB phase. The needle-like TiB phase tends to transform into dot-like particles with the decrease in energy density. Additionally, with the increase in TiB2 content, the TiB phase is coarsened due to the increased nucleation rate and more reactions. The grain morphology is found to largely depend on the translational speed of solid–fluid interface determined by the temperature gradient and cooling rate. Also, the microhardness of the as-built TiB/Ti6Al4V composites is obviously improved. More interestingly, as the energy density increases, the microhardness of the as-built TiB/Ti6Al4V composites firstly increases and then decreases due to the synergy of grain size and different morphologies and distribution of TiB phases. The wear resistance of TiB/Ti6Al4V composites is far superior to that of Ti6Al4V alloy owing to the increased microhardness resulted from the uniform distribution of the hard TiB phase in the matrix.

关键词： Selective laser melting TiB/Ti6Al4V composites Energy density Densification behavior Microhardness Wear resistance