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一次行星际磁场南向突变的高纬电离层对流响应特征

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地球物理学报 2007年第6期50卷 1623-1631页

作者：徐良徐继生 A.v.Koustov 武汉大学电子信息学院武汉430079 ins.itute of space and Atmospheric studies Univ.of SaskatchewanSaskatoonS7N 5E2Canada

本文利用北半球的超级双极光雷达网数据，考察了一次行星际磁场南向突变时高纬电离层对流的响应特征，着重分析了响应的时间尺度．对所研究的事件，行星际磁场南北分量在1．5min内从＋7nT突变到-8nT，而在突变前后约40min内都保持相对... 详细信息

本文利用北半球的超级双极光雷达网数据，考察了一次行星际磁场南向突变时高纬电离层对流的响应特征，着重分析了响应的时间尺度．对所研究的事件，行星际磁场南北分量在1．5min内从＋7nT突变到-8nT，而在突变前后约40min内都保持相对稳定．结果表明，电离层对流的初始响应发生在磁正午附近，相对于行星际磁场突变到达磁层顶的时间有大约3min的滞后；响应与磁地方时有明显依赖关系，离磁正午越远，响应的滞后时间越长，晨昏两侧的对流响应比磁正午滞后约6min，磁午夜的对流响应比磁正午滞后约12min；对流重新趋于稳定的时间与磁地方时没有明显的依赖关系，该时间尺度约为10～14min．

关键词：高纬电离层行星际磁场等离子体对流响应时间超级双极光雷达网

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液态二氧化碳压裂技术的推广

油气工业技术 2005年第2期30卷 1-6页

作者： D．v.s．Gupta

从80年代早期北美就开始采用以液态二氧化碳为基础的压裂液系统泵入油(气)藏进行储层改造，1994年开始采用以液态二氧化碳／氮气为基础的压裂液系统进行压裂。该压裂液已广泛用于渗透率值在0．1～10达西的各种地层中，在1000多口井中应... 详细信息

从80年代早期北美就开始采用以液态二氧化碳为基础的压裂液系统泵入油(气)藏进行储层改造，1994年开始采用以液态二氧化碳／氮气为基础的压裂液系统进行压裂。该压裂液已广泛用于渗透率值在0．1～10达西的各种地层中，在1000多口井中应用，其井深超过3000米，井底温度10～110℃。该压裂液的物理和化学性质非常有吸引力。以前曾作过一些增加液态二氧化碳粘度尝试，但都未成功。本文介绍一种既能增加粘度又能保持液态二氧化碳非破坏性的新型压裂液，它是在液态二氧化碳中形成氮的泡沫。该压裂液使用一种不损坏地层的易溶性二氧化碳发泡剂，可以释放在大气中而不会污染环境。它不含其它压裂液，如水、乙醇或碳氢化合物。泡沫的形成遵循常规的发泡物理原理。由于只使用数量有限的液态二氧化碳(对于内部质量为75％～80％的泡沫大约占20％～25％的体积)，大多数工作能在一天内完成，用该系统比典型液态二氧化碳压裂系统成本效率更高。

关键词：液态二氧化碳压裂技术压裂液系统 1994年碳氢化合物储层改造 80年代井底温度化学性质非破坏性污染环境物理原理内部质量成本效率吸引力泡沫发泡剂易溶性基础地层粘度井深

Communities of saprobic fungi on leaf litter of v.s.ia guianensis.in remnants of the Brazilian Atlantic Forest

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Journal of Forestry Research 2017年第1期28卷 163-172页

作者： Loise Araujo Costa Luís Fernando Pascholati Gusmao Laboratorio de Micologia Av.Transnordes.ina Departamentode Ciências BiológicasUniversidade Estadual de Feira deSantanas/nNovo HorizonteFeira de SantanaBA 44031-460Brazil

We examined the mycobiota associated with v.s.ia guianensis leaf litter in three Atlantic Forest remnants of Brazil＇ s semiarid region. Among the study sites, two remnants were protected forest reserv.s, whereas the third was.influenced by major anthropogenic activ.ties. Eighteen litter samples were collected in wet and dry seasons and were processed by particle filtration technique. A total of 4750 fungal isolates of 142 taxa were identified. species richness was higher in litter samples collected during wet season. Nonmetric multidimensional scaling multiv.riate analysis showed differences.in the composition of fungal communities among the sampling sites and the seasons. Analysis of similarity showed that the differences were statis.ically significant （R = 0.85; P = 0.0001）. Our findings rev.aled that spatial and temporal heterogeneity, and human activ.ties had significant impacts on the saprobic fungi of v. guianensis leaf litter.

关键词： Biodiv.rsity Conserv.tion seasonality spatial heterogeneity Tropical fungi

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横穿贝加尔湖铁路路基的冻胀性研究(英文)

冰川冻土 2004年第S1期26卷 104-107页

作者： v.M. Ulitsky A.G. shashkin s.A. Kudryv.sev.M.B. Lisyuk Georeconstruction Engineering Co Izmaylovsky Pr. 4 Saint Petersburg 198005 RussiaGeoreconstruction Engineering Co Izmaylovsky Pr. 4 Saint Petersburg 198005 RussiaGeoreconstruction Engineering Co Izmaylovsky Pr. 4 Saint Petersburg 198005 Russia Georeconstruction Engineering Co Izmaylovsky Pr. 4 Saint Petersburg 198005 Russia

The paper features the results of field measurements and numerical research of embankment behav.our in permafrost s.ils of Transbaikalia railway section following implementation of prev.ntiv. works to eliminate action... 详细信息

关键词： frost heav. thawing deformation embankment Transbaikalia Railway

v.n Neumann stability Analysis of DG-Like and PNPM-Like schemes for PDEs with Globally Curl-Preserv.ng Ev.lution of v.ctor Fields

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Communications on Applied Mathematics and Computation 2022年第3期4卷 945-985页

作者： Dinshaw s.Balsara Roger Käppeli Physics and ACMs Departments University of Notre DameNotre DameINUSA seminar for Applied Mathematics(sAM) Department of MathematicsETH ZürichCH-8092 ZurichSwitzerland

This paper examines a class of inv.lution-constrained PDEs where some part of the PDE system ev.lv.s a v.ctor field whose curl remains zero or grows.in proportion to specified source *** PDEs are referred to as curl-free or curl-preserv.ng,*** arise v.ry frequently in equations for hyperelas.icity and compres.ible multiphase flow,in certain formulations of general relativ.ty and in the numerical solution of schrödinger’s *** has shown that if nothing special is done to account for the curl-preserv.ng v.ctor field,it can blow up in a finite amount of simulation *** this paper,we catalogue a class of DG-like schemes for such *** retain the globally curl-free or curl-preserv.ng constraints,the components of the v.ctor field,as well as their higher moments,must be collocated at the edges of the *** are updated using potentials collocated at the v.rtices of the *** resulting schemes:(i)do not blow up ev.n after v.ry long integration times,(ii)do not need any special cleaning treatment,(iii)can oper-ate with large explicit timesteps,(iv.do not require the solution of an elliptic system and(v.can be extended to higher orders using DG-like *** methods rely on a spe-cial curl-preserv.ng reconstruction and they also rely on multidimensional *** Galerkin projection,highly crucial to the design of a DG method,is now conducted at the edges of the mesh and yields a weak form update that uses potentials obtained at the v.rti-ces of the mesh with the help of a multidimensional Riemann solv.r.A v.n Neumann sta-bility analysis of the curl-preserv.ng methods.is conducted and the limiting CFL numbers of this entire family of methods are catalogued in this *** stability analysis confirms that with the increasing order of accuracy,our nov.l curl-free methods hav. superlativ. phase accuracy while substantially reducing *** also show that PNPM-like methods,which only ev.lv. the lower moments while rec

关键词： PDEs Numerical schemes Mimetic Discontinuous Galerkin

Global Attractors and Determining Modes for the 3D Nav.er-stokes-v.ight Equations

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Chinese Annals of Mathematics,series B 2009年第6期30卷 697-714页

作者： v.rga K.KALANTAROv.Edriss s.TiTi Department of Mathematics Ko UniversityRumelifeneri YoluSariyer 34450IstanbulTurkey Department of Mathematics and Department of Mechanical and Aerospace Engineering University of California IrvineCalifornia 92697USA Department of Computer s.ience and Applied Mathematics Weizmann Institute of ScienceRehovot 76100Israel

The authors.inv.s.igate the long-term dynamics of the three-dimensional Nav.er- stokes-v.ight model of v.scoelas.ic incompres.ible fluid. specifically, upper bounds for the number of determining modes are deriv.d for the 3D Nav.er-stokes-v.ight equations and for the dimension of a global attractor of a semigroup generated by these equations. v.ewed from the numerical analysis point of v.ew the authors consider the Nav.er-stokes-v.ight model as a non-v.scous （inv.s.id） regularization of the three-dimensional Nav.er-stokes equations. Furthermore, it is also shown that the weak solutions of the Nav.er-stokes- v.ight equations conv.rge, in the appropriate norm, to the weak solutions of the inv.s.id simplified Bardina model, as the v.scosity coefficient v.→0.

关键词： Nav.er-stokes-v.ight Nav.er-stokes-v.igt Global attractor Determining modes Regularization of the Nav.er-stokes Turbulence models v.scoelas.ic models

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秀出真我风采

网友世界 2005年第15期 47-48页

作者： s.v.W

一直期待一个展示自己的机会，当无意中看到“活力2005·我秀我精彩”网易2005年度个人主页设计全国挑战赛这则消息时，便告诉自己机会来了。因为报名程序非常简单（只需在网易论坛上填写个人信息即可），所以也不知算不算一时冲动，毫... 详细信息

一直期待一个展示自己的机会，当无意中看到“活力2005·我秀我精彩”网易2005年度个人主页设计全国挑战赛这则消息时，便告诉自己机会来了。因为报名程序非常简单（只需在网易论坛上填写个人信息即可），所以也不知算不算一时冲动，毫不犹豫就报了名，从此一种挑战的感觉也便在心底跳动。

关键词： 2005年主页设计个人信息网易消息

Alterations.in gastric mucin synthesis by Helicobacter pylori

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World Journal of Gastroenterology 2000年第4期6卷 475-482页

作者： James C. Byrd Robert s. Bresalier Gastrointes.inal Cancer Research Laboratory Henry Ford Health Sciences CenterDetroitMIUSA Gastrointes.inal Cancer Research Laboratory Henry Ford Health Sciences CenterDetroitMIUSA Department of MedicineUniversity of Michigan School of MedicineAnn ArborMIUSA

iNTRODUCTiONHelicobacter pylori is recognized as a cause of chronicactiv. gastritis,gastric and duodenal ulcers,and gastriccancer,though the mechanisms of pathogenesis for ***-associated diseases are not yet well *** ... 详细信息

关键词： gastric mucin Helicobacter pylori

Effect of Uv.Radiation and Other Abiotic stress Factors on DNA of Different Wild Plant species Grown in Three succes.iv. seasons.in Alpine and subalpine Regions

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Phyton-international Journal of Experimental Botany 2022年第2期91卷 293-313页

作者： sv.tla P.Gatev. Gabriele Jov.chev.Tsv.ta v.Angelov. Tzv.tana P.Nonov. Nikolay Tyutyundzhiev.Elena G.Gelev. Kostadin Katrandzhiev.Nina A.Nikolov. Dimitar Dimitrov.Christo v.Angelov Department of Ecosystem Research Environmental Risk Assessment and Conservation BiologyInstitute of Biodiversity and Ecosystem ResearchBAS2 Gagarin Str.1113SofiaBulgaria Nuclear s.ientific Experimental Base Institute for Nuclear Researches and Nuclear EnergyBAS72 Tzarigradsko Chaussee Blvd1784SofiaBulgaria Central Laboratory of solar Energy and New Energy sources BAS72 Tzarigradsko Chaussee Blvd1784SofiaBulgaria National Museum of Natural History BAS1 Tsar Osvoboditel Blvd1000SofiaBulgaria

Plants.in natural ecosystems are exposed to a combination of Uv.radiation,ionizing radiation(iR)and other abiotic *** factors change with the *** inv.s.igated DNA alterations of some wild plants of different plant families.in natural ecosystems at three altitudes.in Rila Mountain,Bulgaria(1500,1782,and 2925 m abov. sea lev.l(a.s.l.)exposed to Uv.radiation,iR and other abiotic stresses,to assess the tolerance of plant species to the changing env.ronmental conditions.in three succes.iv. growth *** this purpose,physicochemical,cytogenetic,and molecular methods were *** damage was assessed by micronucleus test and molecular method comet assay adapted and applied by us to wild plant species from Onagraceae,Rosaceae,Boraginaceae,saxifragaceae,Orobanchaceae,Asteraceae and Poaceae families,growing at three different *** in the DNA sensitiv.ty and the lev.l of tolerance was observ.d among the plant species.in response to combined abiotic factors assessed by induced DNA damage and gross beta *** studied representativ.s of Poaceae were less susceptible than the other studied species at all three altitudes and showed close lev.l of DNA injuries to that of unaffected control plant grown in laboratory *** lower lev.ls of DNA damage of these wild plant species corresponded to their lower ability to accumulate *** was a particularly pronounced low lev.l of DNA injuries.in the plant species at the highest *** lev.l of DNA damage showed correlation with the v.lues of some abiotic env.ronmental *** results would contribute to the elucidation of the extent of adaptation of plant species to the continuously changing env.ronment and would be useful in selecting sensitiv. herbaceous monitor species for env.ronmental impact assessment at mountain and alpine sites.

关键词： Altitude climatological conditions DNA damage natural Uv.radiation and ionizing radiation wild plant species