Pub Date : 1982-11-01DOI: 10.1016/0390-6035(82)90099-2
O. Cozar, I. Ardelean, Gh. Ilonca
EPR and magnetic susceptibility experiments have been performed on x(V2O5) (1−x) [2B2O3 · PbO] glasses with x varying in the range 0.2 ⩽ x ⩽ 55 mol %. The modifications of the EPR spectra with the increasing of V2O5 content are explained supposing that these are the result of the superposition of two EPR signals, one with a well resolved hyperfine structure typical for isolated vanadyl ions and one consisting from a broad line without structure typical for clustered ions. The last species of ions is dominating in the glasses with x > 45 mol % V2O5.
For the samples with x ⩾ 35 mol % V2O5 the reciprocal magnetic susceptibility follows the Curie behaviour. From magnetic data and considering that only V4+ and V5+ ions occur in the studied glasses we have estimated the V4+ ions content as well as the NV4+/NV5+ ratio, the last being approximately constant+ ∼ 0.14.
{"title":"EPR and magnetic susceptibility studies of vanadium lead-borate glasses","authors":"O. Cozar, I. Ardelean, Gh. Ilonca","doi":"10.1016/0390-6035(82)90099-2","DOIUrl":"https://doi.org/10.1016/0390-6035(82)90099-2","url":null,"abstract":"<div><p>EPR and magnetic susceptibility experiments have been performed on x(V<sub>2</sub>O<sub>5</sub>) (1−x) [2B<sub>2</sub>O<sub>3</sub> · PbO] glasses with x varying in the range 0.2 ⩽ <em>x</em> ⩽ 55 mol %. The modifications of the EPR spectra with the increasing of V<sub>2</sub>O<sub>5</sub> content are explained supposing that these are the result of the superposition of two EPR signals, one with a well resolved hyperfine structure typical for isolated vanadyl ions and one consisting from a broad line without structure typical for clustered ions. The last species of ions is dominating in the glasses with x > 45 mol % V<sub>2</sub>O<sub>5</sub>.</p><p>For the samples with x ⩾ 35 mol % V<sub>2</sub>O<sub>5</sub> the reciprocal magnetic susceptibility follows the Curie behaviour. From magnetic data and considering that only V<sup>4+</sup> and V<sup>5+</sup> ions occur in the studied glasses we have estimated the V<sup>4+</sup> ions content as well as the N<sub>V<sup>4+</sup></sub>/N<sub>V<sup>5+</sup></sub> ratio, the last being approximately constant<sup>+</sup> ∼ 0.14.</p></div>","PeriodicalId":18221,"journal":{"name":"Materials Chemistry","volume":"7 6","pages":"Pages 755-765"},"PeriodicalIF":0.0,"publicationDate":"1982-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0390-6035(82)90099-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72091531","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}
Pub Date : 1982-11-01DOI: 10.1016/0390-6035(82)90103-1
Jaime Amorós
{"title":"Introduction a la ciencia de los materiales. (Spanish edition of the book, “ Science of materials”)","authors":"Jaime Amorós","doi":"10.1016/0390-6035(82)90103-1","DOIUrl":"https://doi.org/10.1016/0390-6035(82)90103-1","url":null,"abstract":"","PeriodicalId":18221,"journal":{"name":"Materials Chemistry","volume":"7 6","pages":"Pages 803-804"},"PeriodicalIF":0.0,"publicationDate":"1982-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0390-6035(82)90103-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72091535","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}
Pub Date : 1982-11-01DOI: 10.1016/0390-6035(82)90099-2
O. Cozar, I. Ardelean, G. Ilonca
{"title":"EPR and magnetic susceptibility studies of vanadium lead-borate glasses","authors":"O. Cozar, I. Ardelean, G. Ilonca","doi":"10.1016/0390-6035(82)90099-2","DOIUrl":"https://doi.org/10.1016/0390-6035(82)90099-2","url":null,"abstract":"","PeriodicalId":18221,"journal":{"name":"Materials Chemistry","volume":"12 1","pages":"755-765"},"PeriodicalIF":0.0,"publicationDate":"1982-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74209158","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}
Pub Date : 1982-11-01DOI: 10.1016/0390-6035(82)90098-0
Krzysztof Jankowski , Jacline Belanger , J.R.Jocelyn Pare
The Karplus equation is more than twenty years old. Is that equation still worth while for the chemist today? Can it be applied to materials science? An example of its possible role in wood chemistry, for instance in the conformational analysis of cellulosic materials, macromolecules, biopolymers, carbohydrates and other wood derivatives is presented. NMR data are advantageously compared to X-ray diffraction data for the purpose of conformational assessment. However, there exists several Karplus-type equations, thus rendering its use by materials chemist more complicated: which one applies to the system under study? We therefore review some of the best fit calculations for the Karplus equation, suggest a uniform criterion to evaluate all Karplus-type equations, and include a review of 3J calculations using the Karplus equations.
{"title":"Vingt ans apres: To Karplus or not to Karplus?","authors":"Krzysztof Jankowski , Jacline Belanger , J.R.Jocelyn Pare","doi":"10.1016/0390-6035(82)90098-0","DOIUrl":"https://doi.org/10.1016/0390-6035(82)90098-0","url":null,"abstract":"<div><p>The Karplus equation is more than twenty years old. Is that equation still worth while for the chemist today? Can it be applied to materials science? An example of its possible role in wood chemistry, for instance in the conformational analysis of cellulosic materials, macromolecules, biopolymers, carbohydrates and other wood derivatives is presented. NMR data are advantageously compared to X-ray diffraction data for the purpose of conformational assessment. However, there exists several Karplus-type equations, thus rendering its use by materials chemist more complicated: which one applies to the system under study? We therefore review some of the best fit calculations for the Karplus equation, suggest a uniform criterion to evaluate all Karplus-type equations, and include a review of <sup>3</sup>J calculations using the Karplus equations.</p></div>","PeriodicalId":18221,"journal":{"name":"Materials Chemistry","volume":"7 6","pages":"Pages 737-754"},"PeriodicalIF":0.0,"publicationDate":"1982-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0390-6035(82)90098-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72091529","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}
Pub Date : 1982-11-01DOI: 10.1016/0390-6035(82)90100-6
J. Amorós, J. Solana, E. Villar
{"title":"The relationship between surface tension and isothermal compressibility in simple liquids","authors":"J. Amorós, J. Solana, E. Villar","doi":"10.1016/0390-6035(82)90100-6","DOIUrl":"https://doi.org/10.1016/0390-6035(82)90100-6","url":null,"abstract":"","PeriodicalId":18221,"journal":{"name":"Materials Chemistry","volume":"11 1","pages":"767-771"},"PeriodicalIF":0.0,"publicationDate":"1982-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85999444","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}
Pub Date : 1982-11-01DOI: 10.1016/0390-6035(82)90102-X
H. Braun, P. Herger
{"title":"On the separation of the contributions of powder particle cores and intergranular contacts to the electric resistivity of the compressed powder materials","authors":"H. Braun, P. Herger","doi":"10.1016/0390-6035(82)90102-X","DOIUrl":"https://doi.org/10.1016/0390-6035(82)90102-X","url":null,"abstract":"","PeriodicalId":18221,"journal":{"name":"Materials Chemistry","volume":"1 1","pages":"787-802"},"PeriodicalIF":0.0,"publicationDate":"1982-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72668687","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}
Pub Date : 1982-11-01DOI: 10.1016/0390-6035(82)90102-X
H. Braun , P. Herger
Since the early measurements of Skaupy and Kantrowitc31 it is well-known that the electric conductivity of powder materials exhibits various, very complex problems. However, for a long period of time, the principal interest in the electric conductivity of conducting powders was focused to its application on carbon brushes2, sintered electric contacts3 and electrochemical batteries4. The most prevailing sintering of metallic or ceramic parts was not affected by the electric conductivity of the raw powder. During the last years, however, electric heating methods, e.g. flash sintering, inductive sintering etc., have been developped and have partly been introduced into the sintering practice. One of the most urgent problems of these new procedures is the powder resistivity. Again, the most important problem of measuring powder resistivities is the separation of the contribution of powder particle cores and surfaces to the entire resistivity of the green powder pressing, before the heating process starts. A few considerations and experimental result will be given here below.
{"title":"On the separation of the contributions of powder particle cores and intergranular contacts to the electric resistivity of the compressed powder materials","authors":"H. Braun , P. Herger","doi":"10.1016/0390-6035(82)90102-X","DOIUrl":"https://doi.org/10.1016/0390-6035(82)90102-X","url":null,"abstract":"<div><p>Since the early measurements of Skaupy and Kantrowitc3<sup>1</sup> it is well-known that the electric conductivity of powder materials exhibits various, very complex problems. However, for a long period of time, the principal interest in the electric conductivity of conducting powders was focused to its application on carbon brushes<sup>2</sup>, sintered electric contacts<sup>3</sup> and electrochemical batteries<sup>4</sup>. The most prevailing sintering of metallic or ceramic parts was not affected by the electric conductivity of the raw powder. During the last years, however, electric heating methods, e.g. flash sintering, inductive sintering etc., have been developped and have partly been introduced into the sintering practice. One of the most urgent problems of these new procedures is the powder resistivity. Again, the most important problem of measuring powder resistivities is the separation of the contribution of powder particle cores and surfaces to the entire resistivity of the green powder pressing, before the heating process starts. A few considerations and experimental result will be given here below.</p></div>","PeriodicalId":18221,"journal":{"name":"Materials Chemistry","volume":"7 6","pages":"Pages 787-802"},"PeriodicalIF":0.0,"publicationDate":"1982-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0390-6035(82)90102-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72091527","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}
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