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Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy最新文献

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Oscillations anharmoniques dans les puits de cavités souterraines 地下竖井的非谐波振荡
Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy Pub Date : 1997-12-01 DOI: 10.1016/S1251-8069(97)82335-4
Pierre Bérest, Jean Bergues, Benoît Brouard
{"title":"Oscillations anharmoniques dans les puits de cavités souterraines","authors":"Pierre Bérest,&nbsp;Jean Bergues,&nbsp;Benoît Brouard","doi":"10.1016/S1251-8069(97)82335-4","DOIUrl":"10.1016/S1251-8069(97)82335-4","url":null,"abstract":"<div><p>Strongly anharmonic pressure oscillations generated by fluid injection stops have been observed at the well head of an underground cavern. They are due to a small gas pocket, trapped in the well head, whose existence was unknown.</p></div>","PeriodicalId":100304,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy","volume":"325 12","pages":"Pages 701-707"},"PeriodicalIF":0.0,"publicationDate":"1997-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1251-8069(97)82335-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"102238479","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
Synthèse et structure d’un oxalate de gadolinium ne contenant pas de molécule d’eau libre, [Gd(H2O)3]2(C2O4)3 不含游离水分子[Gd(H2O)3]2(C2O4)3草酸钆的合成与结构
Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy Pub Date : 1997-12-01 DOI: 10.1016/S1251-8069(99)80065-7
David Trollet, Stéphane Roméro, Alain Mosset, Jean-Christian Trombe
{"title":"Synthèse et structure d’un oxalate de gadolinium ne contenant pas de molécule d’eau libre, [Gd(H2O)3]2(C2O4)3","authors":"David Trollet,&nbsp;Stéphane Roméro,&nbsp;Alain Mosset,&nbsp;Jean-Christian Trombe","doi":"10.1016/S1251-8069(99)80065-7","DOIUrl":"10.1016/S1251-8069(99)80065-7","url":null,"abstract":"<div><p>A new family of lanthanide oxalate, [Ln(H<sub>2</sub>O)<sub>3</sub>]<sub>2</sub>(C<sub>2</sub>O<sub>4</sub>)<sub>3</sub> with Ln = Eu−Dy, has been characterized through the X-ray structural study of the gadolinium derivative. In contrast to the lanthanide oxalates already known, this structure is free of zeolitic water but it remains layered and the basic building blocks are preserved. The loss of zeolitic water leads to some deformations of the network units.</p></div>","PeriodicalId":100304,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy","volume":"325 11","pages":"Pages 663-670"},"PeriodicalIF":0.0,"publicationDate":"1997-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1251-8069(99)80065-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113063612","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: 1
L’avenir des programmes européens de recherche spatiale 欧洲空间研究计划的未来
Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy Pub Date : 1997-12-01 DOI: 10.1016/S1251-8069(99)80066-9
Roger-Maurice Bonnet
{"title":"L’avenir des programmes européens de recherche spatiale","authors":"Roger-Maurice Bonnet","doi":"10.1016/S1251-8069(99)80066-9","DOIUrl":"10.1016/S1251-8069(99)80066-9","url":null,"abstract":"<div><p>European space research carried out by ESA, the European Space Agency, has enabled Europe to reclaim the leading positions it had conceded to the USA. But an eventual return to the situation that prevailed in the sixties, when European space research was totally dependent on US planning and technologies is to be feared. Actually, Europe is only spending a quarter of the amount NASA devotes to its space activities. A new approach is required if there is to be any hope of preserving the achievements of almost 40 years of efforts, which isstarting to bear fruit. Halt the budget erosion, improve the , methods of management and the execution of missions, start researches in ‘high tech’, avoid the dispersal of technical and scientific activities, coordinate national efforts with those of ESA: these necessary measures, taken as soon as possible, would allow Europe to keep its rank of a scientific, technological and cultural force.</p></div>","PeriodicalId":100304,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy","volume":"325 11","pages":"Pages 671-684"},"PeriodicalIF":0.0,"publicationDate":"1997-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1251-8069(99)80066-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81598868","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
Vers une modélisation multiéchelle des mélanges turbulents compressibles en présence de forts gradients de masse volumique 在强密度梯度下可压缩湍流混合物的多尺度建模
Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy Pub Date : 1997-12-01 DOI: 10.1016/S1251-8069(99)80061-X
Olivier Grégoire , Denis Souffland , Serge Gauthier , Roland Schiestel
{"title":"Vers une modélisation multiéchelle des mélanges turbulents compressibles en présence de forts gradients de masse volumique","authors":"Olivier Grégoire ,&nbsp;Denis Souffland ,&nbsp;Serge Gauthier ,&nbsp;Roland Schiestel","doi":"10.1016/S1251-8069(99)80061-X","DOIUrl":"10.1016/S1251-8069(99)80061-X","url":null,"abstract":"<div><p>A multiscale closure model for compressible turbulent mixing flows is developed in order to take into account their spectral nature and unsteadiness. A new method is introduced to calibrate the phenomenological coefficients, using the spectral properties of the multiscale closure model. It is based on the Canuto-Goldman analytical model. The Meshkov shock tube experiment is simulated.</p></div>","PeriodicalId":100304,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy","volume":"325 11","pages":"Pages 631-634"},"PeriodicalIF":0.0,"publicationDate":"1997-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1251-8069(99)80061-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76937559","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: 1
The efficiency of coherent states in various domains of semiclassical physics 相干态在半经典物理各个领域中的效率
Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy Pub Date : 1997-12-01 DOI: 10.1016/S1251-8069(99)80062-1
Monique Combescure
{"title":"The efficiency of coherent states in various domains of semiclassical physics","authors":"Monique Combescure","doi":"10.1016/S1251-8069(99)80062-1","DOIUrl":"10.1016/S1251-8069(99)80062-1","url":null,"abstract":"<div><p>In this mini review we describe various aspects of semiclassical coherent-state propagation, ranging from recent experiments in atomic physics to mathematical aspects of ‘quantum chaology’.</p></div>","PeriodicalId":100304,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy","volume":"325 11","pages":"Pages 635-648"},"PeriodicalIF":0.0,"publicationDate":"1997-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1251-8069(99)80062-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"112633776","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
A novel route to β-thymidine β-胸腺嘧啶的新途径
Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy Pub Date : 1997-12-01 DOI: 10.1016/S1251-8069(99)80064-5
Luc Billard, Rachida Benhaddou, Robert Granet, Pierre Krausz
{"title":"A novel route to β-thymidine","authors":"Luc Billard,&nbsp;Rachida Benhaddou,&nbsp;Robert Granet,&nbsp;Pierre Krausz","doi":"10.1016/S1251-8069(99)80064-5","DOIUrl":"10.1016/S1251-8069(99)80064-5","url":null,"abstract":"<div><p>A stereoselective synthesis of <em>β</em>-thymidine using 2-deoxy-<span>D</span>-<em>erythro</em>-pentofuranosyl-trichloroacetimidate as the activating group is reported. This five-step route includes only one chromatographic purification with an overall yield of 30% in <em>β</em>-thymidine and stereoselectivity of approximately 80%.</p></div>","PeriodicalId":100304,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy","volume":"325 11","pages":"Pages 659-662"},"PeriodicalIF":0.0,"publicationDate":"1997-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1251-8069(99)80064-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"102762532","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
Mise en évidence d’une relaxation dur/mou dans un mélange bitume/polymère 在沥青/聚合物混合物中显示硬/软松弛
Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy Pub Date : 1997-12-01 DOI: 10.1016/S1251-8069(99)80059-1
Didier Lesueur , Jean-François Gérard , Didier Martin , Jean-Pascal Planche
{"title":"Mise en évidence d’une relaxation dur/mou dans un mélange bitume/polymère","authors":"Didier Lesueur ,&nbsp;Jean-François Gérard ,&nbsp;Didier Martin ,&nbsp;Jean-Pascal Planche","doi":"10.1016/S1251-8069(99)80059-1","DOIUrl":"10.1016/S1251-8069(99)80059-1","url":null,"abstract":"<div><p>A micromechanical relaxation is observed in a heterogeneous Polymer Modified Bitumen (PMB). This relaxation, theoritically studied by Fröhlich and Sack, arises when a microscopic elastic deformation develops in dispersed phase particles. Thus, two reinforcement domains are highlighted when the material is sheared under a low-strain dynamic mechanical deformation: at low frequency, the polymer-rich dispersed particles are harder than the matrix and behave as hard spheres (undeformable inclusions). At high frequencies, they are soft (deformable), causing a subsequent decrease in the modulus of the PMB. The hard/soft relaxation results in a minimum of phase angle versus frequency.</p></div>","PeriodicalId":100304,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy","volume":"325 11","pages":"Pages 615-620"},"PeriodicalIF":0.0,"publicationDate":"1997-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1251-8069(99)80059-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"95502450","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
Rubriques 标题
Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy Pub Date : 1997-12-01 DOI: 10.1016/S1251-8069(97)82346-9
{"title":"Rubriques","authors":"","doi":"10.1016/S1251-8069(97)82346-9","DOIUrl":"https://doi.org/10.1016/S1251-8069(97)82346-9","url":null,"abstract":"","PeriodicalId":100304,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy","volume":"325 12","pages":"Pages XXIII-XXIV"},"PeriodicalIF":0.0,"publicationDate":"1997-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1251-8069(97)82346-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137124942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Élaboration et caractérisation physico-chimique de nouveaux ferrites mixtes Mo-Co 新型Mo-Co混合铁氧体的制备与物理化学表征
Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy Pub Date : 1997-12-01 DOI: 10.1016/S1251-8069(97)82340-8
Sylvie Douard, Philippe Tailhades, Abel Rousset
{"title":"Élaboration et caractérisation physico-chimique de nouveaux ferrites mixtes Mo-Co","authors":"Sylvie Douard,&nbsp;Philippe Tailhades,&nbsp;Abel Rousset","doi":"10.1016/S1251-8069(97)82340-8","DOIUrl":"10.1016/S1251-8069(97)82340-8","url":null,"abstract":"<div><p>New Mo<sub><em>x</em></sub>Co<sub><em>y</em></sub>Fe<sub>3 − <em>x</em> − <em>y</em></sub>O<sub>4</sub> ferrites have been prepared from hydroxide precursors leading to fine spherical particles. The so-obtained products have quite high substitution rates (x ≈ 0.5 and 0 ⩽ y ⩽ 1), higher than those ever reported for <em>Mo-Co</em> ferrites. The substitution of Fe<sup>2+</sup> ions by Co<sup>2+</sup> ions, which have a stronger magnetocrystalline anisotropy, and the directional order phenomenon both involve an enhancement in coercivity. Nevertheless, because of differences in composition, in cationic distribution and in particle morphology, the <em>Mo-Co</em> ferrites synthesized according to our process show a coercive force lower than that observed by other workers. The cobalt element stabilizes the spinel structure of the ferrites by decreasing their reactivity towards oxygen. Besides, for high cobalt content, a proportion of these ions has the valency state + III.</p></div>","PeriodicalId":100304,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy","volume":"325 12","pages":"Pages 739-747"},"PeriodicalIF":0.0,"publicationDate":"1997-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1251-8069(97)82340-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"98616250","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
Influence de quelques facteurs sur la photodégradation catalytique de l'acide acétique en solution aqueuse par le TiO2 一些因素对二氧化钛催化乙酸在水溶液中的光降解的影响
Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy Pub Date : 1997-12-01 DOI: 10.1016/S1251-8069(97)82339-1
Didier Robert, Franck Rohr, Jean-Victor Weber
{"title":"Influence de quelques facteurs sur la photodégradation catalytique de l'acide acétique en solution aqueuse par le TiO2","authors":"Didier Robert,&nbsp;Franck Rohr,&nbsp;Jean-Victor Weber","doi":"10.1016/S1251-8069(97)82339-1","DOIUrl":"10.1016/S1251-8069(97)82339-1","url":null,"abstract":"<div><p>The photocatalytic degradation of acetic acid in an aqueous suspension of TiO<sub>2</sub> has been studied. The influence of [TiO<sub>2</sub>], [CH<sub>3</sub>COOH] and irradiation time on the rate of disappearance of acetic acid has been demonstrated. We have brought to the fore that the disappearance of acetic acid follows the Langmuir-Hinshelwood model. Finally we have observed the effect of granulometry and the crystalline structure of the catalyst that shows that the degradation is made at the TiO<sub>2</sub> surface.</p></div>","PeriodicalId":100304,"journal":{"name":"Comptes Rendus de l'Académie des Sciences - Series IIB - Mechanics-Physics-Chemistry-Astronomy","volume":"325 12","pages":"Pages 733-738"},"PeriodicalIF":0.0,"publicationDate":"1997-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1251-8069(97)82339-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"111665681","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
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