The Fourier series of the 2π-periodic functions tg(x2)and 1sin(x)and some of their relatives (first of their integrals) are investigated and illustrated with respect to their convergence. These functions are Generali...The Fourier series of the 2π-periodic functions tg(x2)and 1sin(x)and some of their relatives (first of their integrals) are investigated and illustrated with respect to their convergence. These functions are Generalized functions and the convergence is weak convergence in the sense of the convergence of continuous linear functionals defining them. The figures show that the approximations of the Fourier series possess oscillations around the function which they represent in a broad band embedding them. This is some analogue to the Gibbs phenomenon. A modification of Fourier series by expansion in powers cosn(x)for the symmetric part of functions and sin(x)cosn−1(x)for the antisymmetric part (analogous to Taylor series) is discussed and illustrated by examples. The Fourier series and their convergence behavior are illustrated also for some 2π-periodic delta-function-like sequences connected with the Poisson theorem showing non-vanishing oscillations around the singularities similar to the Gibbs phenomenon in the neighborhood of discontinuities of functions. .展开更多
Molten salts play multiple important roles in the electrolysis of solid metal compounds,particularly oxides and sulfides,for the extraction of metals or alloys.Some of these roles are positive in assisting the extract...Molten salts play multiple important roles in the electrolysis of solid metal compounds,particularly oxides and sulfides,for the extraction of metals or alloys.Some of these roles are positive in assisting the extraction of metals,such as dissolving the oxide or sulfide anions,and transporting them to the anode for discharging,and offering the high temperature to lower the kinetic barrier to break the metal-oxygen or metal-sulfur bond.However,molten salts also have unfavorable effects,including electronic conductivity and significant capability of dissolving oxygen and carbon dioxide gases.In addition,although molten salts are relatively simple in terms of composition,physical properties,and decomposition reactions at inert electrodes,in comparison with aqueous electrolytes,the high temperatures of molten salts may promote unwanted electrode-electrolyte interactions.This article reviews briefly and selectively the research and development of the F ray-F arthing-Chen(FFC)Cambridge Process in the past two decades,focusing on observations,understanding,and solutions of various interactions between molten salts and cathodes at different reduction states,including perovskitization,non-wetting of molten salts on pure metals,carbon contamination of products,formation of oxychlorides and calcium intermetallic compounds,and oxygen transfer from the air to the cathode product mediated by oxide anions in the molten salt.展开更多
Using FFC-Cambridge Process to prepare Si from SiO2 is a promising method to prepare nanostructured and highly pure silicon for solar cells.However,the method still has many problems unsolved and the controlling effec...Using FFC-Cambridge Process to prepare Si from SiO2 is a promising method to prepare nanostructured and highly pure silicon for solar cells.However,the method still has many problems unsolved and the controlling effect of the cell voltage on silicon product is not clear.Here we report in this article that nano cluster-like silicon product with purity of 99.95%has been prepared by complete conversion of raw material SiO2,quartz glass plate,using constant cell voltage electrolysis FFC-Cambridge Process.By analysis of XRD,EDS,TEM,HRTEM and ICP-AES as well as the discussion from the thermodynamics calculation,the morphology and components of the product based on the change of cell voltage are clarified.It is clear that pure silicon could be prepared at the cell voltage of 1.7 2.1 V in this reaction system.The silicon material have cluster-like structure which are made of silicon nanoparticles in 20 100 nm size.Interestingly,the cluster-like nano structure of the silicon can be tuned by the used cell voltage.The purity,yield and the energy cost of silicon product prepared at the optimized cell voltage are discussed.The purity of the silicon product could be further improved,hence this method is promising for the preparation of solar grade silicon in future.展开更多
Considerable interest in hydrogen bonding involving chalcogen has been growing since the IUPAC committee has redefined hydrogen bonding. Not only the focus is on unconventional acceptors, but also on donors not discus...Considerable interest in hydrogen bonding involving chalcogen has been growing since the IUPAC committee has redefined hydrogen bonding. Not only the focus is on unconventional acceptors, but also on donors not discussed before. It has been mentioned in previous studies that the proton of the H-C group could be involved in hydrogen bonding, but with conventional acceptors. In this study, we explored the ability of hydrogen bond formation of Se, S and Te acceptors with the H-C donor using Cambridge Structural Database in conjunction with Ab Initio calculations. In the CSD, there are respectively 256, 6249 and 11 R1,R2,-C=Se, R1,R2,-C=S and R1,R2,-C=Te structures that form hydrogen bonds, in which the N,N groups are majority. Except for C=S acceptor which can form a hydrogen bond with its C, C group, both C=Se and C=Te acceptors could form a hydrogen bond only with N,C and N,N groups. CSD analysis shows very similar d (norm) around -0.04 Å, while DFT-calculated interaction for N,C and N,N groups are also similar. Both interaction distances derived from CSD analysis and DFT-calculated interaction energies demonstrate that the acceptors form stable complexes with H-CF3. Besides hydrogen bonds, dispersion interactions are forces stabilizing the complexes since their contribution can reach 50%. Analysis of intra-molecular geometries and Ab Initio partial charges show that this bonding stems from resonance induced C<sup>δ+</sup>=X<sup>δ-</sup> dipoles. In many respects, both C=Se, C=S and C=Te are similar to C=S, with similar d (norm) and calculated interaction strengths.展开更多
In discussing the policy effects of environmental regulation,we should focus not only on whether environmental regulation helps improve the environmental and economic performance of firms,but also on how such improvem...In discussing the policy effects of environmental regulation,we should focus not only on whether environmental regulation helps improve the environmental and economic performance of firms,but also on how such improvement is materialized,i.e.whether the obsolete mode of production is reversed.After matching the database of China’s industrial enterprises with that of pollution emissions from these industrial enterprises,this paper identifies the asymmetric scope of clean production standards to test the effect of environmental regulation on the total factor productivity(TFP)of the industrial enterprises.Our empirical research finds that the implementation of clean production standards may induce TFP improvement.However,such improvement only occurs for polluters who cannot or who barely meet clean production standards and does little to improve the production standards of polluters with low pollution emission,reflecting the yardstick phenomenon of the asymmetric environmental regulation policy effect:While polluters are forced to improve,clean enterprises that pollute less are more likely to take no action.Further research finds that such TFP improvement is materialized primarily by means of overall firm optimization;the compensation effect is insignificant and does not reverse the backward mode of production.Polluters cope with the implementation of clean production standards by purchasing more equipment and expanding capacity,which adds to the tension between the expansion of capacity and the abatement of pollution emission.展开更多
Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes wi...Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes with agent centers in Britain, France, Austral- ia, Japan, Netherlands, New Zealand, and Hong Kong China. The products include traditional printed abstracting and indexing jour- nals, a variety of electronic database which are retrieved through remote on-line and CD-ROM. Recently, the CSA launched network based （IDS） services, which can retrieve hundreds of databases provided by CSA and CSA publishing partners.展开更多
Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes wi...Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes with agent centers in Britain, France, Austral- ia, Japan, Netherlands, New Zealand, and Hong Kong China. The products include traditional printed abstracting and indexing jour- nals, a variety of electronic database which are retrieved through remote on-line and CD-ROM. Recently, the CSA launched network based （IDS） services, which can retrieve hundreds of databases provided by CSA and CSA publishing partners.展开更多
Meteorological and Environmental Research has been included by Cambridge Scientific Abstracts (CSA) since 2011. CSA is a retrieval system published by Cambridge Information Group. CSA was founded in the late 1950’s,a...Meteorological and Environmental Research has been included by Cambridge Scientific Abstracts (CSA) since 2011. CSA is a retrieval system published by Cambridge Information Group. CSA was founded in the late 1950’s,and became part of the CIG family in 1971. CSA’s original mission was publishing secondary source materials relating to the physical sciences. Completely展开更多
Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes wi...Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes with agent centers in Britain, France, Austral- ia, Japan, Netherlands, New Zealand, and Hong Kong China. The products include traditional printed abstracting and indexing jour- nals, a variety of electronic database which are retrieved through remote on-line and CD-ROM. Recently, the CSA launched network based （IDS） services, which can retrieve hundreds of databases provided by CSA and CSA publishing partners.展开更多
Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes wi...Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes with agent centers in Britain, France, Australia, Japan, Netherlands, New Zealand, and Hong Kong China. The products include traditional printed abstracting and indexing journals, a variety of electronic database which are retrieved through remote on-line and CD-ROM. Recently, the CSA launched network based （IDS） services, which can retrieve hundreds of databases provided by CSA and CSA publishing partners.展开更多
Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes wi...Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes with agent centers in Britain, France, Australia, Japan, Netherlands, New Zealand, and Hong Kong China. The products include traditional printed abstracting and indexing journals, a variety of electronic database which are retrieved through remote on-line and CD-ROM. Recently, the CSA launched network based （IDS） services, which can retrieve hundreds of databases provided by CSA and CSA publishing partners.展开更多
Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes wi...Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes with agent centers in Britain, France, Australia, Japan, Netherlands, New Zealand, and Hong Kong China.展开更多
Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of morc than 30 years, the company is an important publisher of publishing abstracts and indexes wi...Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of morc than 30 years, the company is an important publisher of publishing abstracts and indexes with agent centers in Britain, France, Austral- ia, Japan, Netherlands, New Zealand, and Hong Kong China. The products include traditional printed abstracting and indexing jour- nals, a variety of electronic database which are retrieved through remote on-line and CD-ROM. Recently, the CSA launched network based （IDS） services, which can retrieve hundreds of databases provided by CSA and CSA publishing partners.展开更多
Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes wi...Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes with agent centers in Britain, France, Austral- ia, Japan, Netherlands, New Zealand, and Hong Kong China. The products include traditional printed abstracting and indexing jour- nals, a variety of electronic database which are retrieved through remote on-line and CD-ROM. Recently, the CSA lannched network based （IDS） services, which can retrieve hundreds of databases provided by CSA and CSA publishing partners.展开更多
In November 2011, Journal of Arid Land （JAL） was accepted for indexing in Cambridge Science Abstracts （CSA） and Centre for Agriculture and Bioscience Abstracts （CAB Abstracts） after strict assessments by these t...In November 2011, Journal of Arid Land （JAL） was accepted for indexing in Cambridge Science Abstracts （CSA） and Centre for Agriculture and Bioscience Abstracts （CAB Abstracts） after strict assessments by these two databases.展开更多
文摘The Fourier series of the 2π-periodic functions tg(x2)and 1sin(x)and some of their relatives (first of their integrals) are investigated and illustrated with respect to their convergence. These functions are Generalized functions and the convergence is weak convergence in the sense of the convergence of continuous linear functionals defining them. The figures show that the approximations of the Fourier series possess oscillations around the function which they represent in a broad band embedding them. This is some analogue to the Gibbs phenomenon. A modification of Fourier series by expansion in powers cosn(x)for the symmetric part of functions and sin(x)cosn−1(x)for the antisymmetric part (analogous to Taylor series) is discussed and illustrated by examples. The Fourier series and their convergence behavior are illustrated also for some 2π-periodic delta-function-like sequences connected with the Poisson theorem showing non-vanishing oscillations around the singularities similar to the Gibbs phenomenon in the neighborhood of discontinuities of functions. .
文摘Molten salts play multiple important roles in the electrolysis of solid metal compounds,particularly oxides and sulfides,for the extraction of metals or alloys.Some of these roles are positive in assisting the extraction of metals,such as dissolving the oxide or sulfide anions,and transporting them to the anode for discharging,and offering the high temperature to lower the kinetic barrier to break the metal-oxygen or metal-sulfur bond.However,molten salts also have unfavorable effects,including electronic conductivity and significant capability of dissolving oxygen and carbon dioxide gases.In addition,although molten salts are relatively simple in terms of composition,physical properties,and decomposition reactions at inert electrodes,in comparison with aqueous electrolytes,the high temperatures of molten salts may promote unwanted electrode-electrolyte interactions.This article reviews briefly and selectively the research and development of the F ray-F arthing-Chen(FFC)Cambridge Process in the past two decades,focusing on observations,understanding,and solutions of various interactions between molten salts and cathodes at different reduction states,including perovskitization,non-wetting of molten salts on pure metals,carbon contamination of products,formation of oxychlorides and calcium intermetallic compounds,and oxygen transfer from the air to the cathode product mediated by oxide anions in the molten salt.
基金supported by the Solar Energy Initiative of the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.KGCX2-YW-395)
文摘Using FFC-Cambridge Process to prepare Si from SiO2 is a promising method to prepare nanostructured and highly pure silicon for solar cells.However,the method still has many problems unsolved and the controlling effect of the cell voltage on silicon product is not clear.Here we report in this article that nano cluster-like silicon product with purity of 99.95%has been prepared by complete conversion of raw material SiO2,quartz glass plate,using constant cell voltage electrolysis FFC-Cambridge Process.By analysis of XRD,EDS,TEM,HRTEM and ICP-AES as well as the discussion from the thermodynamics calculation,the morphology and components of the product based on the change of cell voltage are clarified.It is clear that pure silicon could be prepared at the cell voltage of 1.7 2.1 V in this reaction system.The silicon material have cluster-like structure which are made of silicon nanoparticles in 20 100 nm size.Interestingly,the cluster-like nano structure of the silicon can be tuned by the used cell voltage.The purity,yield and the energy cost of silicon product prepared at the optimized cell voltage are discussed.The purity of the silicon product could be further improved,hence this method is promising for the preparation of solar grade silicon in future.
文摘Considerable interest in hydrogen bonding involving chalcogen has been growing since the IUPAC committee has redefined hydrogen bonding. Not only the focus is on unconventional acceptors, but also on donors not discussed before. It has been mentioned in previous studies that the proton of the H-C group could be involved in hydrogen bonding, but with conventional acceptors. In this study, we explored the ability of hydrogen bond formation of Se, S and Te acceptors with the H-C donor using Cambridge Structural Database in conjunction with Ab Initio calculations. In the CSD, there are respectively 256, 6249 and 11 R1,R2,-C=Se, R1,R2,-C=S and R1,R2,-C=Te structures that form hydrogen bonds, in which the N,N groups are majority. Except for C=S acceptor which can form a hydrogen bond with its C, C group, both C=Se and C=Te acceptors could form a hydrogen bond only with N,C and N,N groups. CSD analysis shows very similar d (norm) around -0.04 Å, while DFT-calculated interaction for N,C and N,N groups are also similar. Both interaction distances derived from CSD analysis and DFT-calculated interaction energies demonstrate that the acceptors form stable complexes with H-CF3. Besides hydrogen bonds, dispersion interactions are forces stabilizing the complexes since their contribution can reach 50%. Analysis of intra-molecular geometries and Ab Initio partial charges show that this bonding stems from resonance induced C<sup>δ+</sup>=X<sup>δ-</sup> dipoles. In many respects, both C=Se, C=S and C=Te are similar to C=S, with similar d (norm) and calculated interaction strengths.
文摘In discussing the policy effects of environmental regulation,we should focus not only on whether environmental regulation helps improve the environmental and economic performance of firms,but also on how such improvement is materialized,i.e.whether the obsolete mode of production is reversed.After matching the database of China’s industrial enterprises with that of pollution emissions from these industrial enterprises,this paper identifies the asymmetric scope of clean production standards to test the effect of environmental regulation on the total factor productivity(TFP)of the industrial enterprises.Our empirical research finds that the implementation of clean production standards may induce TFP improvement.However,such improvement only occurs for polluters who cannot or who barely meet clean production standards and does little to improve the production standards of polluters with low pollution emission,reflecting the yardstick phenomenon of the asymmetric environmental regulation policy effect:While polluters are forced to improve,clean enterprises that pollute less are more likely to take no action.Further research finds that such TFP improvement is materialized primarily by means of overall firm optimization;the compensation effect is insignificant and does not reverse the backward mode of production.Polluters cope with the implementation of clean production standards by purchasing more equipment and expanding capacity,which adds to the tension between the expansion of capacity and the abatement of pollution emission.
文摘Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes with agent centers in Britain, France, Austral- ia, Japan, Netherlands, New Zealand, and Hong Kong China. The products include traditional printed abstracting and indexing jour- nals, a variety of electronic database which are retrieved through remote on-line and CD-ROM. Recently, the CSA launched network based （IDS） services, which can retrieve hundreds of databases provided by CSA and CSA publishing partners.
文摘Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes with agent centers in Britain, France, Austral- ia, Japan, Netherlands, New Zealand, and Hong Kong China. The products include traditional printed abstracting and indexing jour- nals, a variety of electronic database which are retrieved through remote on-line and CD-ROM. Recently, the CSA launched network based （IDS） services, which can retrieve hundreds of databases provided by CSA and CSA publishing partners.
文摘Meteorological and Environmental Research has been included by Cambridge Scientific Abstracts (CSA) since 2011. CSA is a retrieval system published by Cambridge Information Group. CSA was founded in the late 1950’s,and became part of the CIG family in 1971. CSA’s original mission was publishing secondary source materials relating to the physical sciences. Completely
文摘Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes with agent centers in Britain, France, Austral- ia, Japan, Netherlands, New Zealand, and Hong Kong China. The products include traditional printed abstracting and indexing jour- nals, a variety of electronic database which are retrieved through remote on-line and CD-ROM. Recently, the CSA launched network based （IDS） services, which can retrieve hundreds of databases provided by CSA and CSA publishing partners.
文摘Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes with agent centers in Britain, France, Australia, Japan, Netherlands, New Zealand, and Hong Kong China. The products include traditional printed abstracting and indexing journals, a variety of electronic database which are retrieved through remote on-line and CD-ROM. Recently, the CSA launched network based （IDS） services, which can retrieve hundreds of databases provided by CSA and CSA publishing partners.
文摘Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes with agent centers in Britain, France, Australia, Japan, Netherlands, New Zealand, and Hong Kong China. The products include traditional printed abstracting and indexing journals, a variety of electronic database which are retrieved through remote on-line and CD-ROM. Recently, the CSA launched network based （IDS） services, which can retrieve hundreds of databases provided by CSA and CSA publishing partners.
文摘Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes with agent centers in Britain, France, Australia, Japan, Netherlands, New Zealand, and Hong Kong China.
文摘Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of morc than 30 years, the company is an important publisher of publishing abstracts and indexes with agent centers in Britain, France, Austral- ia, Japan, Netherlands, New Zealand, and Hong Kong China. The products include traditional printed abstracting and indexing jour- nals, a variety of electronic database which are retrieved through remote on-line and CD-ROM. Recently, the CSA launched network based （IDS） services, which can retrieve hundreds of databases provided by CSA and CSA publishing partners.
文摘Cambridge Scientific Abstracts （CSA） is a retrieval system published by Cambridge Information Group. With a history of more than 30 years, the company is an important publisher of publishing abstracts and indexes with agent centers in Britain, France, Austral- ia, Japan, Netherlands, New Zealand, and Hong Kong China. The products include traditional printed abstracting and indexing jour- nals, a variety of electronic database which are retrieved through remote on-line and CD-ROM. Recently, the CSA lannched network based （IDS） services, which can retrieve hundreds of databases provided by CSA and CSA publishing partners.
文摘In November 2011, Journal of Arid Land （JAL） was accepted for indexing in Cambridge Science Abstracts （CSA） and Centre for Agriculture and Bioscience Abstracts （CAB Abstracts） after strict assessments by these two databases.
