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汶川地震同震滑坡物质在震区的滞留和运移及其对龙门山地形演化的影响 被引量:2
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作者 王伟 刘静 +7 位作者 Vincent Godard 张金玉 许冲 李志刚 徐心悦 许强 王鹏 谢克家 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2018年第5期1970-1983,共14页
2008年M_W7.9汶川地震导致龙门山断裂发生强烈地壳变形,同时引发的巨量同震滑坡加速了该地区的地表剥蚀和河流侵蚀.然而,目前尚缺少系统的数据定量研究滑坡物质的运移以及河流侵蚀速率随时间的演化规律,这些对理解龙门山前缘物质的再分... 2008年M_W7.9汶川地震导致龙门山断裂发生强烈地壳变形,同时引发的巨量同震滑坡加速了该地区的地表剥蚀和河流侵蚀.然而,目前尚缺少系统的数据定量研究滑坡物质的运移以及河流侵蚀速率随时间的演化规律,这些对理解龙门山前缘物质的再分配以及强震对活动造山带地形塑造的作用至关重要.为此,本研究在汶川地震后的6年间,对震区沱江上游3条支流湔江、石亭江、绵远河流域进行了多期次的定点现代河沙采样.通过系统测量河沙中的石英10Be浓度,并与震前已发表的数据进行对比,发现如下基本特点:(1)震后河沙10 Be浓度均有明显降低,表明同震滑坡物质对河沙的稀释作用;(2)震后河流对河沙的运移量增加为震前的1.3~18.5倍,因此震后龙门山地区侵蚀速率短期显著增加;(3)初步估计得到汶川地震产生的滑坡物质被完全运移出造山带所需要的时间至少为100~4000年,接近龙门山地区强震复发周期;(4)震间和同震产生的构造变形和地表剥蚀在空间上具有互补性.考虑到地表剥蚀引起的地壳均衡反弹效应,认为类似汶川地震的强震有利于龙门山的隆升.认识震前、震时和震后的地壳变形及侵蚀过程有助于更好地理解单次强震事件对高原边界龙门山地形演化的作用. 展开更多
关键词 龙门山 汶川地震 同震滑坡 河流卸载 地形演化
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Hydro-geochemistry of groundwater and surface water in Dschang town(West Cameroon):Alkali and alkaline-earth elements ascertain lithological and anthropogenic constraints 被引量:1
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作者 Yemeli Elida Joelle Temgoua Emile +5 位作者 Kengni Lucas Ambrosi Jean-Paul Momo-nouazi Mathieu Silatsa-Tedou Francis Brice Wamba Franck Robean Tchakam-Kamtchueng Brice 《Journal of Groundwater Science and Engineering》 2021年第3期212-224,共13页
The study aims to identify a suitable site for open and bore well in a farmhouseusing ground magnetic survey in south India.It also aims to define depth to granitoid and structural elements which traverse the selected... The study aims to identify a suitable site for open and bore well in a farmhouseusing ground magnetic survey in south India.It also aims to define depth to granitoid and structural elements which traverse the selected area.Magnetic data(n=84)measured,processed and interpreted as qualitative and quantitatively.The results of total magnetic intensities indicate that the area is composed of linear magnetic lows trending NE-SW direction and circular to semi-circular causative bodies.The magnetic values ranged from-137 nT to 2345 nT with a mean of 465 nT.Reduction to equator shows significant shifting of causative bodies in the southern and northern directions.Analytical signal map shows exact boundary of granitic bodies.Cosine directional filter has brought out structural element trending NE-SW direction.Results of individual profile brought to light structurally weak zone between 90 m and 100 m in all the profile lines.Sudden decrease of magnetic values from 2042 nT to 126 nT noticed in profile line 6 between 20 m and 30 m indicates fault occurrence.Magnetic breaks obtained from these maps were visualized,interpreted and identified two suitable sites for open and bore well.Radially averaged power spectrum estimates depth of shallow and deep sources in 5 m and 50 m,respectively.Euler method has also been applied to estimate depth of granitoid and structural elements using structural indexes 0,1,2,and 3 and found depth ranges from<10 m to>90 m.Study indicates magnetic method is one of the geophysical methods suitable for groundwater exploration and site selection for open and borewells. 展开更多
关键词 Alkali/alkaline-earth elements Groundwater and surface water Geochemical anomaly Anthropogenic impact Dschang-Cameroon
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星形胶质细胞对脑血管功能的调控
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作者 Martine Cohen-Salmon Leila Slaoui +7 位作者 Noémie Mazaré Alice Gilbert Marc Oudart Rodrigo Alvear-Perez Xabier Elorza-Vidal Oana Chever Anne-Cécile Boulay 杜一星(编译) 《神经损伤与功能重建》 2021年第2期F0003-F0003,共1页
星形胶质细胞是脑内神经胶质细胞中数量最多的一种类型,对脑血管系统具有重要的影响。它们参与调控血管周围内稳态、血脑屏障的完整性、与外周免疫系统的交流、血液中代谢物的转移以及与神经元活动相应的血管收缩。这些调控过程发生在... 星形胶质细胞是脑内神经胶质细胞中数量最多的一种类型,对脑血管系统具有重要的影响。它们参与调控血管周围内稳态、血脑屏障的完整性、与外周免疫系统的交流、血液中代谢物的转移以及与神经元活动相应的血管收缩。这些调控过程发生在由血管周围星形胶质细胞突起组成的几乎完全覆盖了脑血管特殊界面中。科学家直到最近才开始研究这种界面的形成方式及其如何影响脑血管功能。本文综述了有关星形胶质细胞在调节脑血管系统中作用的文献。涵盖了胶质血管界面的解剖结构和发育、已知的胶质血管功能和分子因素、后者在某些病理生理情况下的作用以及最近开发的用于检验星形胶质细胞在血管界面作用的尖端实验工具。最后,本综述重点介绍了该研究领域中的一些尚未解决的问题。 展开更多
关键词 星形胶质细胞 脑血管系统 胶质血管界面
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The local contribution to the microwave background radiation
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作者 Jean-Claude Pecker Jayant V.Narlikar +1 位作者 Francois Ochsenbein Chandra Wickramasinghe 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2015年第4期461-474,共14页
The observed microwave background radiation (MBR) is commonly in- terpreted as the relic of an early hot universe, and its observed features (spectrum and anisotropy) are explained in terms of properties of the ea... The observed microwave background radiation (MBR) is commonly in- terpreted as the relic of an early hot universe, and its observed features (spectrum and anisotropy) are explained in terms of properties of the early universe. Here we describe a complementary, even possibly alternative, interpretation of MBR, first proposed in the early 20th century, and adapt it to modern observations. For example, the stellar Hipparcos data show that the energy density of starlight from the Milky Way, if suit- ably thermalized, yields a temperature of ~2.81 K. This and other arguments given here strongly suggest that the origin of MBR may lie, at least in a very large part, in re-radiation of thermalized galactic starlight. The strengths and weaknesses of this alternative radical explanation are discussed. 展开更多
关键词 Galaxy: stellar content -- (cosmology:) cosmic microwave background-- cosmology: observations
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Littoral landforms of Lake Hulun and Lake Buir(China and Mongolia):Wind-driven hydro-sedimentary dynamics and resulting clastics distribution
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作者 Li Wang Mathieu Schuster +8 位作者 Shi-Wei Xin Florin Zainescu Xin-Yu Xue Joep Storms Jan-Hendrik May Alexis Nutz Helena van der Vegt Guilherme Bozetti Zai-Xing Jiang 《Journal of Palaeogeography》 SCIE CSCD 2024年第2期309-326,共18页
Two rectangular-shaped lakes,Lake Hulun and Lake Buir,located at the boundary between China and Mongolia,only c.75 km apart and therefore experiencing similar wind fields,have been studied based on satellite images an... Two rectangular-shaped lakes,Lake Hulun and Lake Buir,located at the boundary between China and Mongolia,only c.75 km apart and therefore experiencing similar wind fields,have been studied based on satellite images and field surveys in order to compare their geomorphological and sedimentological characteristics.The wind-driven hydrodynamics,which have a significant effect on the development of littoral landforms and on sediment distribution,have been discussed for the two similar lakes that experienced a prevailing wind perpendicular to their long axis.A conceptual model related to wind-driven water bodies and sediment distribution is proposed.Wave-influenced to wave-dominated deltas,beaches,spits,and eolian dune deposits develop around these two lakes,with a strikingly similar distribution pattern.These features locally inform the longshore drift and help reconstruct the water circulation induced by wind forcing.Under the NW prevailing wind regime,the spits developed on the SW coast with a NW—SE extension,which was influenced by the NW—SE longshore currents.The same influence was observed in the delta extension in the NE area.The differences lie in the presence of fan deltas in the NW region of Lake Hulun,but not in Lake Buir.Additionally,the width of the beach and eolian deposits on the downwind coast of Lake Hulun is three times greater than that of Lake Buir which were caused by the differences in sediment supply and wind fetch between the two lakes.Lake Hulun and Lake Buir provide two reliable examples to understand the relationship among the wind field,provenance,hydrodynamics,landforms,and asymmetrical distribution of clastics in elongated lakes.They also represent relevant modern analogs,which may also be of guiding significance to wind-driven sand body prediction in lacustrine basins. 展开更多
关键词 Wind-driven lakes FETCH Sedimentary facies Hydrodynamics Geomorphology Spits Shoreline Lake Hulun Lake Buir
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Lensless imaging through thin scattering layers under broadband illumination 被引量:4
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作者 WEI LI BINGJIAN WANG +2 位作者 TENGFEI WU FEIHU XU XIAOPENG SHAO 《Photonics Research》 SCIE EI CAS CSCD 2022年第11期2471-2487,共17页
Lensless scattering imaging is a prospective approach to microscopy in which a high-resolution image of an object is reconstructed from one or more measured speckle patterns, thus providing a solution in situations wh... Lensless scattering imaging is a prospective approach to microscopy in which a high-resolution image of an object is reconstructed from one or more measured speckle patterns, thus providing a solution in situations where the use of imaging optics is not possible. However, current lensless scattering imaging methods are typically limited by the need for a light source with a narrowband spectrum. Here, we propose two general approaches that enable single-shot lensless scattering imaging under broadband illumination in both noninvasive [without point spread function(PSF) calibration] and invasive(with PSF calibration) modes. The first noninvasive approach is based on a numerical refinement of the broadband pattern in the cepstrum incorporated with a modified phase retrieval strategy. The latter invasive approach is correlation inspired and generalized within a computational optimization framework. Both approaches are experimentally verified using visible radiation with a full-width-at-half-maximum bandwidth as wide as 280 nm(Δλ∕λ = 44.8%) and a speckle contrast ratio as low as 0.0823. Because of its generality and ease of implementation, we expect this method to find widespread applications in ultrafast science,passive sensing, and biomedical applications. 展开更多
关键词 SPECTRUM ILLUMINATION SPECKLE
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Cyclin-dependent kinase 7 inhibitor THZ1 in cancer therapy
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作者 Bin-Bin Li Bo Wang +6 位作者 Cheng-Ming Zhu Di Tang Jun Pang Jing Zhao Chun-Hui Sun Miao-Juan Qiu Zhi-Rong Qian 《Chronic Diseases and Translational Medicine》 CSCD 2019年第3期155-169,共15页
Current cancer therapies have encountered adverse response due to poor therapeutic efficiency,severe side effects and acquired resistance to multiple drugs.Thus,there are urgent needs for finding new cancer-targeted p... Current cancer therapies have encountered adverse response due to poor therapeutic efficiency,severe side effects and acquired resistance to multiple drugs.Thus,there are urgent needs for finding new cancer-targeted pharmacological strategies.In this review,we summarized the current understanding with THZ1,a covalent inhibitor of cyclin-dependent kinase 7(CDK7),which demonstrated promising anti-tumor activity against different cancer types.By introducing the anti-tumor behaviors and the potential targets for different cancers,this review aims to provide more effective approaches to CDK7 inhibitor-based therapeutic agents and deeper insight into the diverse tumor proliferation mechanisms. 展开更多
关键词 THZ1 Cyclin-dependent kinase 7 Cancer therapy TRANSCRIPTION Super-enhancer
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WNK家族基因在小鼠肾脏表达的特性分析 被引量:2
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作者 吕晶玉 Jean Marie GASC +1 位作者 Xavier Jeunemaitre 赵彦艳 《中华肾脏病杂志》 CAS CSCD 北大核心 2004年第2期90-93,共4页
目的检测WNK1和WNK4基因在小鼠肾脏组织中的表达位点。方法RT-PCR方法扩增WNK1和WNK4基因片段作为探针,在小鼠多组织膜上进行Northern印迹杂交。将上述片段克隆入pGEM-T载体,测序证实后,体外转录RNA探针并在小鼠肾脏石蜡组织切片上进行... 目的检测WNK1和WNK4基因在小鼠肾脏组织中的表达位点。方法RT-PCR方法扩增WNK1和WNK4基因片段作为探针,在小鼠多组织膜上进行Northern印迹杂交。将上述片段克隆入pGEM-T载体,测序证实后,体外转录RNA探针并在小鼠肾脏石蜡组织切片上进行原位杂交。结果WNK1基因广泛表达在小鼠各组织中,在肾脏有9.5kb强杂交信号。WNK4基因主要表达在肾脏组织中,有4.4kb杂交信号。原位杂交显示WNK1基因仅表达在肾脏远曲小管中,而WNK4除表达在肾脏远曲小管外,还表达在髓质集合管上。结论WNK1和WNK4基因均在肾脏中有表达,WNK4基因在肾脏中表达比WNK1基因更广泛。 展开更多
关键词 WNK家族基因 小鼠 肾脏表达 肾脏组织 RT-PCR 原位杂交
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The role of Fusobacteriu mnucleatum in colorectal cancer:from carcinogenesis to clinical management 被引量:6
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作者 Chun-Hui Sun Bin-Bin Li +9 位作者 Bo Wang Jing Zhao Xiao-Ying Zhang Ting-Ting Li Wen-Bing Li Di Tang Miao-Juan Qiu Xin-Cheng Wang Cheng-Ming Zhu Zhi-Rong Qian 《Chronic Diseases and Translational Medicine》 CSCD 2019年第3期178-187,共10页
Colorectal cancer(CRC)is a common malignant tumor that affects people worldwide.Metagenomic analyses have shown an enrichment of Fusobacterium nucleatum(F.nucleatum)in colorectal carcinoma tissue;many studies have ind... Colorectal cancer(CRC)is a common malignant tumor that affects people worldwide.Metagenomic analyses have shown an enrichment of Fusobacterium nucleatum(F.nucleatum)in colorectal carcinoma tissue;many studies have indicated that F.nucleatum is closely related to the colorectal carcinogenesis.In this review,we provide the latest information to reveal the related molecular mechanisms.The known virulence factors of F.nucleatum promote adhesion to intestinal epithelial cells via FadA and Fap2.Besides,Fap2 also binds to immune cells causing immunosuppression.Furthermore,F.nucleatum recruits tumor-infiltrating immune cells,thus yielding a pro-inflammatory microenvironment,which promotes colorectal neoplasia progression.F.nucleatum was also found to potentiate CRC development through toll-like receptor 2(TLR2)/toll-like receptor 4(TLR4)signaling and microRNA(miRNA)-21 expression.In addition,F.nucleatum increases CRC recurrence along with chemoresistance by mediating a molecular network of miRNA-18a*,miRNA-4802,and autophagy components.Moreover,viable F.nucleatum was detected in mouse xenografts of human primary colorectal adenocarcinomas through successive passages.These findings indicated that an increased number o f F.nucleatum in the tissues is a biomarker for the diagnosis and prognosis of CRC,and the underlying molecular mechanism can probably provide a potential intervention treatment strategy for patients with F.nucleatum-associaied CRC. 展开更多
关键词 Fusobacterium nucleatum:Colorectal carcinoma CARCINOGENESIS Immune microenvironment Intervention therapy
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柏拉图哲学三圈--倾听、哲学现实与知识
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作者 M.福柯 于奇智 《世界哲学》 CSSCI 北大核心 2018年第3期17-29,共13页
柏拉图哲学致力于如下三个圈的建构与交织。它们是倾听圏、哲学现实圈与知识圈。倾听圈表明,哲学只能面向那些想倾听它的人,只有得到倾听才会成为论说,才会是现实的。哲学现实圈意味着,哲学论说作为自我为自我的努力,作为实践,只有被伴... 柏拉图哲学致力于如下三个圈的建构与交织。它们是倾听圏、哲学现实圈与知识圈。倾听圈表明,哲学只能面向那些想倾听它的人,只有得到倾听才会成为论说,才会是现实的。哲学现实圈意味着,哲学论说作为自我为自我的努力,作为实践,只有被伴随、得到支持和运用才会成为现实的,因此,主体通过一系列实践来建立自我关系、完成自我设计并为自我而努力。知识圈就是严格哲学意义上的知识,旨在使人认识事物的存在本身之所是,揭示事物的本质。上述三个圈体现了哲学现实的三种条件、三种界定或三种观点。什么是哲学现实?哲学现实就是勇敢面对权力,即哲学实践,由如下三种能力表现出来:学习灵敏(eumathês)、过目不忘(mnêm8n)与推理能力(logizesthai dunatos)。总之,哲学不仅是逻各斯(logos),而且是行动(ergon),而哲学现实处于自我与自我的关系之中。 展开更多
关键词 柏拉图 倾听 哲学现实 知识
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SENTINELS FOR FERIODIC DISTRIBUTED SYSTEMS
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作者 JACQUES LOUIS LIONS 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 1989年第3期285-291,共7页
For periodic distributed systems the author reduces the "entinels" problem to a problem of controllability type and uses suitable adaptations of of HUM (Hilbert Uniqueness Method) to gives olutions to the or... For periodic distributed systems the author reduces the "entinels" problem to a problem of controllability type and uses suitable adaptations of of HUM (Hilbert Uniqueness Method) to gives olutions to the original "sentinels" problem. 展开更多
关键词 assume MAINTAIN GIVING ENOUGH SENTINEL 二七 introd pursue entine TOWARD
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Common microscopic origin of the phase transitions in Ta_(2)NiS_(5) and the excitonic insulator candidate Ta_(2)NiSe_(5)
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作者 Lukas Windgätter Malte Rösner +5 位作者 Giacomo Mazza Hannes Hübener Antoine Georges Andrew J.Millis Simone Latini Angel Rubio 《npj Computational Materials》 SCIE EI CSCD 2021年第1期1919-1932,共14页
The structural phase transition in Ta-NiSes has been envisioned as driven by the formation of an excitonic insulating phase.However,the role of structural and electronic instabilities on crystal symmetry breaking has ... The structural phase transition in Ta-NiSes has been envisioned as driven by the formation of an excitonic insulating phase.However,the role of structural and electronic instabilities on crystal symmetry breaking has yet to be disentangled.Meanwhile,the phase transition in its complementary material Ta_(2)NiS_(5)does not show any experimental hints of an excitonic insulating phase.We present a microscopic investigation of the electronic and phononic effects involved in the structural phase transition in Ta_(2)NiSe_(5)and Ta-Niss using extensive first-principles calculations.In both materials the crystal symmetries are broken by phonon instabilities,which in tum lead to changes in the electronic bandstructure also observed in the experiment.A total energy landscape analysis shows no tendency towards a purely electronic instability and we find that a sizeable lattice distortion is needed to open a bandgap.We conclude that an excitonic instability is not needed to explain the phase transition in both Ta_(2)NiSe_(5)and Ta_(2)NiS_(5). 展开更多
关键词 phase STRUCTURAL TRANSITIONS
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Electrochemical synthesis and the functionalization of few layer graphene in ionic liquid and redox ionic liquid
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作者 Maria Gómez-Mingot Amarnath Chellachamy Anbalagan +1 位作者 Hyacinthe Randriamahazaka Jalal Ghilane 《Science China Chemistry》 SCIE EI CAS CSCD 2018年第5期598-603,共6页
Electrochemical reductive exfoliation of graphite to few layered graphene(FLG) in presence of 1-ethyl-2,3-dimethyl imidazolium bis(trifluoromethylsulfonyl) imide ionic liquid and redox ionic liquid based ferrocene has... Electrochemical reductive exfoliation of graphite to few layered graphene(FLG) in presence of 1-ethyl-2,3-dimethyl imidazolium bis(trifluoromethylsulfonyl) imide ionic liquid and redox ionic liquid based ferrocene has been investigated. Thus, by applying a mild negative potential(-2.7 V vs. Fc/Fc^+) to carbon electrode in ionic liquid graphene flakes could be generated. The generated materials have been characterized by X-ray photoelectron spectroscopy, Raman spectroscopy, high resolution transmission electron microscopy and atomic force microscopy. XPS and Raman analysis show that the electrochemical reductive exfoliation provides the formation of FLG. The thickness of the resulting FLG was found to be ranged between 4 and1 nm. HR-TEM images reveal the formation of few graphene layers and in some cases single graphene layer was observed.Moreover, this electrochemical route conduces to the formation of ionic liquid functionalized FLG. Finally, the reductive exfoliation was further investigated in the presence of redox ionic liquid. XPS and electrochemical measurements confirm the presence of ferrocene. 展开更多
关键词 electrochemistry reductive exfoliation ionic liquid graphene
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