发布求助
文献互助 智能选刊 最新文献

Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics最新文献

筛选
英文 中文
Gravitational wave detection by laser interferometry – on earth and in space 用激光干涉测量法探测引力波——在地球上和在太空中
Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics Pub Date : 2001-11-01 DOI: 10.1016/S1296-2147(01)01271-9
Albrecht Rüdiger , Alain Brillet , Karsten Danzmann , Adalberto Giazotto , Jim Hough
{"title":"Gravitational wave detection by laser interferometry – on earth and in space","authors":"Albrecht Rüdiger ,&nbsp;Alain Brillet ,&nbsp;Karsten Danzmann ,&nbsp;Adalberto Giazotto ,&nbsp;Jim Hough","doi":"10.1016/S1296-2147(01)01271-9","DOIUrl":"10.1016/S1296-2147(01)01271-9","url":null,"abstract":"<div><p>The space project <span>LISA</span> is approved by <span>ESA</span> as a cornerstone mission in the field of ‘fundamental physics’, sharing its goal and principle of operation with the ground-based interferometers currently under construction: the detection and measurement of gravitational waves by laser interferometry. Ground and space detection differ in their frequency ranges, and thus the detectable sources. At low frequencies, ground-based detection is limited by seismic noise, and yet more fundamentally by ‘gravity gradient noise’, thus covering the range from a few Hz to a few kHz. On five sites worldwide, detectors of armlengths from 0.3 to 4<!--> <!-->km are being built, two of them in Europe (<span>GEO</span> and <span>VIRGO</span>). They will progressively be put in operation between 2001 and 2003. Future improved versions are being planned, with data not until 2008, i.e. near the launch of the space project <span>LISA</span>. It is only in space that detection of signals below, say, 1 Hz is possible, opening a wide window to a different class of interesting sources of gravitational waves. The project <span>LISA</span> consists of three spacecraft in heliocentric orbits, forming a triangle of 5 million km sides.</p></div>","PeriodicalId":100307,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics","volume":"2 9","pages":"Pages 1331-1341"},"PeriodicalIF":0.0,"publicationDate":"2001-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1296-2147(01)01271-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87694107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 3
Questioning the equivalence principle 对等效原则的质疑
Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics Pub Date : 2001-11-01 DOI: 10.1016/S1296-2147(01)01272-0
Thibault Damour
{"title":"Questioning the equivalence principle","authors":"Thibault Damour","doi":"10.1016/S1296-2147(01)01272-0","DOIUrl":"10.1016/S1296-2147(01)01272-0","url":null,"abstract":"<div><p>The Equivalence Principle (EP) is not one of the ‘universal’ principles of physics (like the action principle). It is a heuristic hypothesis which was introduced by Einstein in 1907, and used by him to construct his theory of general relativity. In modern language, the (Einsteinian) EP consists in assuming that the only long-range field with gravitational-strength couplings to matter is a massless spin-2 field. Modern unification theories, and notably string theory, suggest the existence of new fields (in particular, scalar fields: ‘dilaton’ and ‘moduli’) with gravitational-strength couplings. In most cases the couplings of these new fields ‘violate’ the EP. If the field is long-ranged, these EP violations lead to many observable consequences (variation of ‘constants’, non-universality of free fall, relative drift of atomic clocks, etc.). The best experimental probe of a possible violation of the EP is to compare the free-fall acceleration of different materials.</p></div>","PeriodicalId":100307,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics","volume":"2 9","pages":"Pages 1249-1256"},"PeriodicalIF":0.0,"publicationDate":"2001-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1296-2147(01)01272-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87066181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 68
MICROSCOPE, testing the equivalence principle in space 显微镜，在空间中测试等效原理
Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics Pub Date : 2001-11-01 DOI: 10.1016/S1296-2147(01)01264-1
Pierre Touboul , Manuel Rodrigues , Gilles Métris , Bernard Tatry
{"title":"MICROSCOPE, testing the equivalence principle in space","authors":"Pierre Touboul ,&nbsp;Manuel Rodrigues ,&nbsp;Gilles Métris ,&nbsp;Bernard Tatry","doi":"10.1016/S1296-2147(01)01264-1","DOIUrl":"10.1016/S1296-2147(01)01264-1","url":null,"abstract":"<div><p>The test of the equivalence principle can be performed in space with orders of magnitude better resolution than in the laboratory, because of the outstanding steady and soft environment of the in-orbit experiment. The expected new experimental results will contribute to the unification of the four interactions, demonstrate the existence of extra scalar interaction or participate in the research for a quantum gravity theory. The MICROSCOPE space mission is being developed within the framework of the Cnes scientific program with the objective of testing the universality of free fall with a 10<sup>−15</sup> accuracy. The concept and the design of the experiment are discussed and the major performance drivers of the room temperature instrument are pointed out. The launch of the drag-free satellite is scheduled for late 2004. By its specific technology demonstration, the mission will open the way to even more accurate acceleration measurements for other space missions in fundamental physics.</p></div>","PeriodicalId":100307,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics","volume":"2 9","pages":"Pages 1271-1286"},"PeriodicalIF":0.0,"publicationDate":"2001-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1296-2147(01)01264-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113419023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 69
Courbure de la frontière d'une zone sèche dans un film en écoulement 流动膜中干燥区域边界的曲率
Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics Pub Date : 2001-11-01 DOI: 10.1016/S1296-2147(01)01249-5
Thomas Podgorski, Jean-Marc Flesselles, Laurent Limat
{"title":"Courbure de la frontière d'une zone sèche dans un film en écoulement","authors":"Thomas Podgorski,&nbsp;Jean-Marc Flesselles,&nbsp;Laurent Limat","doi":"10.1016/S1296-2147(01)01249-5","DOIUrl":"10.1016/S1296-2147(01)01249-5","url":null,"abstract":"<div><p>We study experimentally the shape of dry patches inside a film flowing along an inclined plane at relatively high value of the contact angle <em>θ</em>. Their radius of curvature R near apex, is given by <em>R</em>/<em>l</em><sub>c</sub>∼<em>l</em><sub>c</sub><em>V</em><sub>c</sub>/(<em>Γ</em> sin<em>α</em>)−<em>F</em>(<em>α</em>,<em>θ</em>), where <em>Γ</em> is the flow rate per unit length, <em>α</em> the plate slope, and <em>F</em>(<em>α</em>,<em>θ</em>) is a correction that increases with <em>θ</em> and decreases with <em>α</em> (<em>l</em><sub>c</sub> and <em>V</em><sub>c</sub> are the capillary length and the capillary velocity). A simple model allows us to recover this correction and also the existence of a critical flow rate above which dry patches disappear.</p></div>","PeriodicalId":100307,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics","volume":"2 9","pages":"Pages 1361-1367"},"PeriodicalIF":0.0,"publicationDate":"2001-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1296-2147(01)01249-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78087985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 6
Equivalence principle tests, equivalence theorems, and new long-range forces 等效原理测试，等效定理，和新的远程力
Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics Pub Date : 2001-11-01 DOI: 10.1016/S1296-2147(01)01265-3
Pierre Fayet
{"title":"Equivalence principle tests, equivalence theorems, and new long-range forces","authors":"Pierre Fayet","doi":"10.1016/S1296-2147(01)01265-3","DOIUrl":"10.1016/S1296-2147(01)01265-3","url":null,"abstract":"<div><p>We discuss the possible existence of new long-range forces mediated by spin-1 or spin-0 particles. By adding their effects to those of gravity, they could lead to <em>apparent</em> violations of the equivalence principle. While the vector part in the couplings of a new spin-1 <em>U</em> boson involves, in general, a combination of the <em>B</em> and <em>L</em> currents, there may also be, in addition, an axial part as well. If the new force has a finite range <em>λ</em>, its intensity is proportional to 1/(<em>λ</em><sup>2</sup><em>F</em><sup>2</sup>), <em>F</em> being the extra <em>U</em>(1) symmetry-breaking scale.</p><p>Quite surprisingly, particle physics experiments can provide constraints on such a new force, even if it is extremely weak, the corresponding gauge coupling being extremely small (⪡10<sup>−19</sup>!). An ‘equivalence theorem’ shows that a very light spin-1 <em>U</em> boson does not in general decouple even when its gauge coupling vanishes, but behaves as a quasi-massless spin-0 particle, having pseudoscalar couplings proportional to 1/<em>F</em>. Similarly, in supersymmetric theories, a very light spin-<span><math><mtext>3</mtext><mtext>2</mtext></math></span> gravitino might be detectable as a quasi-massless spin-<span><math><mtext>1</mtext><mtext>2</mtext></math></span> goldstino, despite the extreme smallness of Newton's gravitational constant <em>G</em><sub>N</sub>, provided that the supersymmetry-breaking scale is not too large.</p><p>Searches for such <em>U</em> bosons in <em>ψ</em> and <em>ϒ</em> decays restrict <em>F</em> to be larger than the electroweak scale (the <em>U</em> actually becoming, as an axion, quasi ‘invisible’ in particle physics for sufficiently large <em>F</em>). This provides strong constraints on the corresponding new force and its associated EP violations. We also discuss briefly new spin-dependent forces.</p></div>","PeriodicalId":100307,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics","volume":"2 9","pages":"Pages 1257-1270"},"PeriodicalIF":0.0,"publicationDate":"2001-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1296-2147(01)01265-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78106091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
New space missions for mapping the Earth's gravity field 绘制地球重力场的新太空任务
Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics Pub Date : 2001-11-01 DOI: 10.1016/S1296-2147(01)01269-0
Georges Balmino
{"title":"New space missions for mapping the Earth's gravity field","authors":"Georges Balmino","doi":"10.1016/S1296-2147(01)01269-0","DOIUrl":"https://doi.org/10.1016/S1296-2147(01)01269-0","url":null,"abstract":"<div><p>The knowledge of the gravity field of the Earth and of an associated reference surface of altitudes (the geoid) is necessary for geodesy, for improving theories of the physics of the planet interior and for modeling the ocean circulation in absolute. This knowledge comes from several observing techniques but, although it benefited from the artificial satellite approach, it remains incomplete and erroneous in places. Within a reasonable future, a substantial improvement can only come from new space techniques. Thanks to the intense lobbying by the concerned geoscientists, the coming decade will see the advent of three techniques already proposed in the seventies and to be implemented by different space agencies; these are the CHAMP, GRACE and GOCE missions.</p></div>","PeriodicalId":100307,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics","volume":"2 9","pages":"Pages 1353-1359"},"PeriodicalIF":0.0,"publicationDate":"2001-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1296-2147(01)01269-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"92105952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 6
Elastography 弹性成像
Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics Pub Date : 2001-10-01 DOI: 10.1016/S1296-2147(01)01255-0
Jonathan Ophir , Faouzi Kallel , Tomy Varghese , Elisa Konofagou , S.K.S.Kaisar Alam , Thomas Krouskop , Brian Garra , Raffaella Righetti
{"title":"Elastography","authors":"Jonathan Ophir ,&nbsp;Faouzi Kallel ,&nbsp;Tomy Varghese ,&nbsp;Elisa Konofagou ,&nbsp;S.K.S.Kaisar Alam ,&nbsp;Thomas Krouskop ,&nbsp;Brian Garra ,&nbsp;Raffaella Righetti","doi":"10.1016/S1296-2147(01)01255-0","DOIUrl":"10.1016/S1296-2147(01)01255-0","url":null,"abstract":"<div><p>We present a concise summary of some of the fundamentals and of our work in the field of elastography over the past 12 years. This summary is not exhaustive, since several recent reviews of this area are available. We begin by presenting some relevant background material from the field of biomechanics, which forms the foundation of this work. We then proceed to discuss the basic principles and limitations that are involved in the production of strain images (elastograms) of biological tissues. Early results as well as current results from biological tissues in vitro and in vivo are shown. We conclude with some thoughts regarding the potential of elastography for medical diagnosis.</p></div>","PeriodicalId":100307,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics","volume":"2 8","pages":"Pages 1193-1212"},"PeriodicalIF":0.0,"publicationDate":"2001-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1296-2147(01)01255-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86985808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics Pub Date : 2001-10-01 DOI: 10.1016/S1296-2147(01)01263-X
A.Claude Boccara (Rédacteur en chef invités / Guest editor), Mathias Fink (Rédacteur en chef invités / Guest editor)
{"title":"","authors":"A.Claude Boccara (Rédacteur en chef invités / Guest editor),&nbsp;Mathias Fink (Rédacteur en chef invités / Guest editor)","doi":"10.1016/S1296-2147(01)01263-X","DOIUrl":"https://doi.org/10.1016/S1296-2147(01)01263-X","url":null,"abstract":"","PeriodicalId":100307,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics","volume":"2 8","pages":"Pages 1069-1070"},"PeriodicalIF":0.0,"publicationDate":"2001-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1296-2147(01)01263-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136931706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Effects of curvature on hydrothermal waves instability of radial thermocapillary flows 曲率对径向热毛细流热液波不稳定性的影响
Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics Pub Date : 2001-10-01 DOI: 10.1016/S1296-2147(01)01232-X
Nicolas Garnier , Christiane Normand
{"title":"Effects of curvature on hydrothermal waves instability of radial thermocapillary flows","authors":"Nicolas Garnier ,&nbsp;Christiane Normand","doi":"10.1016/S1296-2147(01)01232-X","DOIUrl":"10.1016/S1296-2147(01)01232-X","url":null,"abstract":"<div><p>The stability of a thermocapillary flow in an extended cylindrical geometry is analyzed. This flow occurs in a thin liquid layer with a disk shape when a radial temperature gradient is applied along the horizontal free surface. Besides the aspect ratio, a second parameter related to the local curvature is introduced to describe completely the geometrical effects. We recover classical hydrothermal waves as predicted by Smith and Davis, but the properties of these waves are shown to evolve with the curvature parameter, thus leading to a nonuniform pattern over the cell. Moreover, it is shown that the problem is not invariant with respect to the exchange of the hot and cold sides.</p></div>","PeriodicalId":100307,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics","volume":"2 8","pages":"Pages 1227-1233"},"PeriodicalIF":0.0,"publicationDate":"2001-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1296-2147(01)01232-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80467873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 21
Diffuse optical imaging and spectroscopy, in vivo 漫射光学成像和光谱学，在体内
Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics Pub Date : 2001-10-01 DOI: 10.1016/S1296-2147(01)01251-3
Amir H. Gandjbakhche
{"title":"Diffuse optical imaging and spectroscopy, in vivo","authors":"Amir H. Gandjbakhche","doi":"10.1016/S1296-2147(01)01251-3","DOIUrl":"10.1016/S1296-2147(01)01251-3","url":null,"abstract":"<div><p>Based on photon migration the new goal of diffuse optical imaging is to reveal optical contrasts in the depth of biological tissues. We discuss first the origin of contrast mechanism (absorption, fluorescence and scattering) used on diffuse optical imaging and spectroscopy. Then, various experimental approaches are described based on CW, pulsed and modulated light excitation and detection. Theoretical models which provide solutions for direct and inverse problems are presented using random walk theory. Finally two studies on breast imaging and on the use of fluorescence exogeneous markers are discussed in detail.</p></div>","PeriodicalId":100307,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IV - Physics-Astrophysics","volume":"2 8","pages":"Pages 1073-1089"},"PeriodicalIF":0.0,"publicationDate":"2001-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1296-2147(01)01251-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"98164305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 12
首页 上一页 下一页 尾页
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整，为了账户安全，请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
请完成安全验证×
相关产品
×
本文献相关产品
联系我们：info@booksci.cn Book学术提供免费学术资源搜索服务，方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号：481959085
Book学术官方微信