A promising method to improve the attosecond pulse intensity has been theoretically pre- sented by properly adding an ultraviolet pulse into the orthogonal two-color field. The results show that by properly adding a 1...A promising method to improve the attosecond pulse intensity has been theoretically pre- sented by properly adding an ultraviolet pulse into the orthogonal two-color field. The results show that by properly adding a 125 nm ultraviolet pulse to the orthogonal two-color field, not only the harmonic yield is enhanced by 2 orders of magnitude compared with the original orthogonal two-color field case, but also the single short quantum path, which is selected to contribute to the harmonic spectrum, results in an ultrabroad 152 eV bandwidth. Moreover, by optimizing the laser parameters, we find that the harmonic enhancement is not very sen- sitive to the pulse duration and the polarized angle of the assisted ultraviolet pulse, which is much better for experimental realization. As a result, an isolated pulse with duration of 38 as can be obtained, which is 2 orders of magnitude improvement in comparison with the original two-color orthogonal field case.展开更多
By using a new generally projective Riccati equation method and with the help of symbolic computation,we consider a nonlinear Gross-Pitaevskii equation with weak bias magnetic and time-dependent laser fields. As a res...By using a new generally projective Riccati equation method and with the help of symbolic computation,we consider a nonlinear Gross-Pitaevskii equation with weak bias magnetic and time-dependent laser fields. As a result,some new soliton solutions, rational function solution, and periodic solutions are obtained.展开更多
In this paper, with the non-salient pole permanent magnet linear synchronous motor (PMLSM)being cited, by using Fourier transform method and "slot-by-slot", "pole -by-pole" current approach, a 3D e...In this paper, with the non-salient pole permanent magnet linear synchronous motor (PMLSM)being cited, by using Fourier transform method and "slot-by-slot", "pole -by-pole" current approach, a 3D electromagnetic field model of PMLSM is established. Special attention is paid to its structure and the influence of longitudinal and transverse end effect. The distribution of electromagnetic field of PMLSM can be obtained directly and promptly by using FFT algorithm. It can also be used for the analysis of other LSM.展开更多
For microseisimic monitoring it is difficult to determine wave modes and their propagation velocity. In this paper, we propose a new method for automatically inverting in real time the source characteristics of micros...For microseisimic monitoring it is difficult to determine wave modes and their propagation velocity. In this paper, we propose a new method for automatically inverting in real time the source characteristics of microseismic events in mine engineering without wave mode identification and velocities. Based on the wave equation in a spherical coordinate system, we derive a tomographic imaging equation and formulate a scanning parameter selection criterion by which the microseisimic event maximum energy and corresponding parameters can be determined. By determining the maximum energy positions inside a given risk district, we can indentify microseismic events inside or outside the risk districts. The synthetic and field examples demonstrate that the proposed tomographic imaging method can automatically position microseismic events by only knowing the risk district dimensions and range of velocities without identifying the wavefield modes and accurate velocities. Therefore, the new method utilizes the full wavefields to automatically monitor microseismic events.展开更多
In this paper, the stability of disclination ring in nematie liquid crystals is studied. In the presence of saddle-splay elasticity (characterized by k24) the disclination ring has a universal equilibrium radius. De...In this paper, the stability of disclination ring in nematie liquid crystals is studied. In the presence of saddle-splay elasticity (characterized by k24) the disclination ring has a universal equilibrium radius. Depending on the values of the saddle-splay constant k24, the universal equilibrium radius is altered. When k24 〉 0.92k (m = 1/2) and k24 〉 0.88k (m =-1/2), the disclination will be a point rather than a ring, where k is the Frank elastic constant in the one-constant approximation.展开更多
Loess is widely distributed in China and the Loess Plateau is one of the major areas where strong earthquakes often take place. The seismic amplification effects were discovered in the Plateau during the Wenchuan Ms8....Loess is widely distributed in China and the Loess Plateau is one of the major areas where strong earthquakes often take place. The seismic amplification effects were discovered in the Plateau during the Wenchuan Ms8.0 earthquake and some other strong events. Based on earth tremor observation, borehole exploration and site seismic response analysis, the site effects of topography of Loess Yuan on ground motion were investigated in details. The earth tremor investigation shows that predominant frequencies at the bottom sites of Loess Yuan are greater than those at the top obviously. The sites seismic response analysis shows that the Loess Yuan may amplify peak ground acceleration (PGA) by 1.44 2.0 times. Therefore, site effects of mountains and loess topography on ground motion should be taken account into in seismic design in loess regions.展开更多
Latvia is a new European Union country, with 20-year experience in the efforts to develop the energy policy that would favour reliable supply of the state with energy and promote its effective and rational utilization...Latvia is a new European Union country, with 20-year experience in the efforts to develop the energy policy that would favour reliable supply of the state with energy and promote its effective and rational utilization. The energy law should take into consideration the technological progress and increasing energy consumption as well as the poorly regulated sphere of production and utilization. At present, new regulations are needed, as the existent ones have become outdated and unable to ensure stable development of the energy sector. However, the lack of experience and sometimes external influence could lead to a situation when the new law would not be conducive to the industrial development but vice-versa-would slow it down. Since Latvia has been confronted by counterproductive laws, it is highly important to estimate beforehand the future impact of legislation on the state economy. On issue of for the country is now to guarantee-by force of law-the optimal share of renewable energy in the national energy mix. The objective set within the framework of European Union policy is to achieve a 40% share of renewable energy by 2020; therefore, it is necessary to work out a separate law concerning the RES (renewable energy sources). The new RES law is to regulate support and to promote increase in the share of renewable. However, there are many influencing factors--not clearly specified outlooks for the energy sector and national economy development, the interests of energy importers, lobbying, etc.; these factors can make the RES law not only ineffective but even negatively affecting the RES share stability in the state energy balance. It is therefore essential, before the law has been adopted, to thoroughly analyze it so that the optimal variant is accepted.展开更多
The focus of this article will be centered on five Spanish chemists who were refugees in Mexico after the Civil War and provided a strong drive in developing Mexican chemistry. Their names are: Antonio Madinaveitia T...The focus of this article will be centered on five Spanish chemists who were refugees in Mexico after the Civil War and provided a strong drive in developing Mexican chemistry. Their names are: Antonio Madinaveitia Tabuyo, Jos6 Giral Pereira, Modesto Bargall6 Ard6vol, Francisco Giral Gonz^ilez, and Jos6 Ignacio Bolivar Goyanes. This article starts with the panorama of science in Europe (mainly Spain) and in Mexico from the end of the 19th Century to the beginning of the 20th century. It is also included the development of chemistry in Germany in the 19th century. The paper includes a short out line of these scientists' work in Europe, as well as focusing on their contributions to the development of Chemistry in Mexico, in the areas of Organic, Inorganic, Physical and Pharmacy. A conclusion is the importance of their contribution to Mexican chemistry through two institutions: the National University and the National Polytechnic Institute.展开更多
The article interested in the universities in the global market. Author briefly describes the situation of the many universities of the point of view of education, research, orientation, system of financing and manage...The article interested in the universities in the global market. Author briefly describes the situation of the many universities of the point of view of education, research, orientation, system of financing and management of the universities. The whole article is based on the author's practical experiences. The research objective was to determine how the professional community is looking at private universities and state universities. It was based on the opinion of the quality of graduates and the number of academic staff who are working at state universities These academics have mostly negative view of private universities as well as the knowledge of graduates of these private schools. However, the opinion ofstaffin practice, especially managers in manufacturing companies, trading companies, companies selling services, as well as senior officials in government, are not so negative. By contrast in certain areas such as marketing, business, management, Information and Communication Technology etc., was rather neutral or positive. The politicians were interested about these information with regard to educational reform (reform of universities is still not actual--note the author) and the expected necessary cuts of spending to higher education from the state budget. Unfortunately, the research project due to political changes in 2009 was not completed and obtained only partial results. Despite of this fact the author decided to process the article below Opinions on the topic of public vs. private univeristies were mainly obtained informally from experts from academic area (both public and private), managers, various specialists, but also from the students themselves. In conclusion man can say that the demand for people who are able to quickly demonstrate their knowledge in practice is still stronger. The title becomes second-rate (unfortunately not quite in the public and state administration). Very strong demand is the active practice of communication in English (it fulfilles especially private universities) Graduates of technical universities in the classical fields are sought less in the labor market. Very high pressure is developed by state universities to private. This implies a lack of professors and associate professors who can work in full time at private universities which are more flexible and better adapt to labor market requirements. Stronger position have private universities that are in any way connected with foreign partners from developed countries展开更多
A transverse Ising spin system, in the presence of time-dependent longitudinal field, is studied by the effective-field theory (EFT). The effective-field equations of motion of the average magnetization are given fo...A transverse Ising spin system, in the presence of time-dependent longitudinal field, is studied by the effective-field theory (EFT). The effective-field equations of motion of the average magnetization are given for the simple cubic lattice (Z ---- 6) and the honeycomb lattice (Z = 3). The Liapunov exponent A is calculated for discussing the stability of the magnetization and it is used to determine the phase boundary. The dynamic phase transition diagrams in ho/ZJ - F/ZJ plane and in ho/ZJ - T/ZJ plane have been drawn, and there is no dynamical tricritical point on the dynamic phase transition boundary. The effect of the thermal fluctuations upon the dynamic phase boundary has been discussed.展开更多
This paper presents the results of a research study carried out with students of China University of Geosciences to analyze the influence of readers' cognitive styles (field dependent/field neutral/field independe...This paper presents the results of a research study carried out with students of China University of Geosciences to analyze the influence of readers' cognitive styles (field dependent/field neutral/field independent) and reading strategies on their reading performance, including the total reading score, global inference questions, factual and detail questions, main idea questions, lexical inference questions. Results show the correlations between cognitive style and most of the reading questions are not statistically significant, except for the total reading scores and performance of global inference question. One-way ANOVA shows that there is significant difference between the FN and FD group in total reading score and global inference question. However, when the reading strategies have been partialled out of the correlations between cognitive style and reading scores, the remaining correlation with the total reading score and global inference and lexical inference reaches significance. This indicates the different information processing of FD/FI learners and the important role of direct reading strategies for all learners. Teachers can help their students become more effective readers by encouraging them to apply direct reading strategies, and apply different indirect reading strategies based on their different cognitive styles.展开更多
文摘A promising method to improve the attosecond pulse intensity has been theoretically pre- sented by properly adding an ultraviolet pulse into the orthogonal two-color field. The results show that by properly adding a 125 nm ultraviolet pulse to the orthogonal two-color field, not only the harmonic yield is enhanced by 2 orders of magnitude compared with the original orthogonal two-color field case, but also the single short quantum path, which is selected to contribute to the harmonic spectrum, results in an ultrabroad 152 eV bandwidth. Moreover, by optimizing the laser parameters, we find that the harmonic enhancement is not very sen- sitive to the pulse duration and the polarized angle of the assisted ultraviolet pulse, which is much better for experimental realization. As a result, an isolated pulse with duration of 38 as can be obtained, which is 2 orders of magnitude improvement in comparison with the original two-color orthogonal field case.
基金国家重点基础研究发展计划(973计划),National Key Basic Research Development of China
文摘By using a new generally projective Riccati equation method and with the help of symbolic computation,we consider a nonlinear Gross-Pitaevskii equation with weak bias magnetic and time-dependent laser fields. As a result,some new soliton solutions, rational function solution, and periodic solutions are obtained.
文摘In this paper, with the non-salient pole permanent magnet linear synchronous motor (PMLSM)being cited, by using Fourier transform method and "slot-by-slot", "pole -by-pole" current approach, a 3D electromagnetic field model of PMLSM is established. Special attention is paid to its structure and the influence of longitudinal and transverse end effect. The distribution of electromagnetic field of PMLSM can be obtained directly and promptly by using FFT algorithm. It can also be used for the analysis of other LSM.
基金support jointly by projects of the National Natural Science Fund Project (40674017 and 50774012)the National Key Basic Research and Development Plan 973 (2010CB226803)
文摘For microseisimic monitoring it is difficult to determine wave modes and their propagation velocity. In this paper, we propose a new method for automatically inverting in real time the source characteristics of microseismic events in mine engineering without wave mode identification and velocities. Based on the wave equation in a spherical coordinate system, we derive a tomographic imaging equation and formulate a scanning parameter selection criterion by which the microseisimic event maximum energy and corresponding parameters can be determined. By determining the maximum energy positions inside a given risk district, we can indentify microseismic events inside or outside the risk districts. The synthetic and field examples demonstrate that the proposed tomographic imaging method can automatically position microseismic events by only knowing the risk district dimensions and range of velocities without identifying the wavefield modes and accurate velocities. Therefore, the new method utilizes the full wavefields to automatically monitor microseismic events.
基金the Natural Science Foundation of Shanghai Municipal Commission of Science and Technology under Grant No.04ZR14059National Natural Science Foundation of China under Grant No.10575068
文摘In this paper, the stability of disclination ring in nematie liquid crystals is studied. In the presence of saddle-splay elasticity (characterized by k24) the disclination ring has a universal equilibrium radius. Depending on the values of the saddle-splay constant k24, the universal equilibrium radius is altered. When k24 〉 0.92k (m = 1/2) and k24 〉 0.88k (m =-1/2), the disclination will be a point rather than a ring, where k is the Frank elastic constant in the one-constant approximation.
基金Foundation item: Projects(40902094, 50978239) supported by the National Natural Science Foundation of China Project(2012IESLZO1) supported by the Fund of the Institute of Earthquake Prediction, CEA, China
文摘Loess is widely distributed in China and the Loess Plateau is one of the major areas where strong earthquakes often take place. The seismic amplification effects were discovered in the Plateau during the Wenchuan Ms8.0 earthquake and some other strong events. Based on earth tremor observation, borehole exploration and site seismic response analysis, the site effects of topography of Loess Yuan on ground motion were investigated in details. The earth tremor investigation shows that predominant frequencies at the bottom sites of Loess Yuan are greater than those at the top obviously. The sites seismic response analysis shows that the Loess Yuan may amplify peak ground acceleration (PGA) by 1.44 2.0 times. Therefore, site effects of mountains and loess topography on ground motion should be taken account into in seismic design in loess regions.
文摘Latvia is a new European Union country, with 20-year experience in the efforts to develop the energy policy that would favour reliable supply of the state with energy and promote its effective and rational utilization. The energy law should take into consideration the technological progress and increasing energy consumption as well as the poorly regulated sphere of production and utilization. At present, new regulations are needed, as the existent ones have become outdated and unable to ensure stable development of the energy sector. However, the lack of experience and sometimes external influence could lead to a situation when the new law would not be conducive to the industrial development but vice-versa-would slow it down. Since Latvia has been confronted by counterproductive laws, it is highly important to estimate beforehand the future impact of legislation on the state economy. On issue of for the country is now to guarantee-by force of law-the optimal share of renewable energy in the national energy mix. The objective set within the framework of European Union policy is to achieve a 40% share of renewable energy by 2020; therefore, it is necessary to work out a separate law concerning the RES (renewable energy sources). The new RES law is to regulate support and to promote increase in the share of renewable. However, there are many influencing factors--not clearly specified outlooks for the energy sector and national economy development, the interests of energy importers, lobbying, etc.; these factors can make the RES law not only ineffective but even negatively affecting the RES share stability in the state energy balance. It is therefore essential, before the law has been adopted, to thoroughly analyze it so that the optimal variant is accepted.
文摘The focus of this article will be centered on five Spanish chemists who were refugees in Mexico after the Civil War and provided a strong drive in developing Mexican chemistry. Their names are: Antonio Madinaveitia Tabuyo, Jos6 Giral Pereira, Modesto Bargall6 Ard6vol, Francisco Giral Gonz^ilez, and Jos6 Ignacio Bolivar Goyanes. This article starts with the panorama of science in Europe (mainly Spain) and in Mexico from the end of the 19th Century to the beginning of the 20th century. It is also included the development of chemistry in Germany in the 19th century. The paper includes a short out line of these scientists' work in Europe, as well as focusing on their contributions to the development of Chemistry in Mexico, in the areas of Organic, Inorganic, Physical and Pharmacy. A conclusion is the importance of their contribution to Mexican chemistry through two institutions: the National University and the National Polytechnic Institute.
文摘The article interested in the universities in the global market. Author briefly describes the situation of the many universities of the point of view of education, research, orientation, system of financing and management of the universities. The whole article is based on the author's practical experiences. The research objective was to determine how the professional community is looking at private universities and state universities. It was based on the opinion of the quality of graduates and the number of academic staff who are working at state universities These academics have mostly negative view of private universities as well as the knowledge of graduates of these private schools. However, the opinion ofstaffin practice, especially managers in manufacturing companies, trading companies, companies selling services, as well as senior officials in government, are not so negative. By contrast in certain areas such as marketing, business, management, Information and Communication Technology etc., was rather neutral or positive. The politicians were interested about these information with regard to educational reform (reform of universities is still not actual--note the author) and the expected necessary cuts of spending to higher education from the state budget. Unfortunately, the research project due to political changes in 2009 was not completed and obtained only partial results. Despite of this fact the author decided to process the article below Opinions on the topic of public vs. private univeristies were mainly obtained informally from experts from academic area (both public and private), managers, various specialists, but also from the students themselves. In conclusion man can say that the demand for people who are able to quickly demonstrate their knowledge in practice is still stronger. The title becomes second-rate (unfortunately not quite in the public and state administration). Very strong demand is the active practice of communication in English (it fulfilles especially private universities) Graduates of technical universities in the classical fields are sought less in the labor market. Very high pressure is developed by state universities to private. This implies a lack of professors and associate professors who can work in full time at private universities which are more flexible and better adapt to labor market requirements. Stronger position have private universities that are in any way connected with foreign partners from developed countries
文摘A transverse Ising spin system, in the presence of time-dependent longitudinal field, is studied by the effective-field theory (EFT). The effective-field equations of motion of the average magnetization are given for the simple cubic lattice (Z ---- 6) and the honeycomb lattice (Z = 3). The Liapunov exponent A is calculated for discussing the stability of the magnetization and it is used to determine the phase boundary. The dynamic phase transition diagrams in ho/ZJ - F/ZJ plane and in ho/ZJ - T/ZJ plane have been drawn, and there is no dynamical tricritical point on the dynamic phase transition boundary. The effect of the thermal fluctuations upon the dynamic phase boundary has been discussed.
文摘This paper presents the results of a research study carried out with students of China University of Geosciences to analyze the influence of readers' cognitive styles (field dependent/field neutral/field independent) and reading strategies on their reading performance, including the total reading score, global inference questions, factual and detail questions, main idea questions, lexical inference questions. Results show the correlations between cognitive style and most of the reading questions are not statistically significant, except for the total reading scores and performance of global inference question. One-way ANOVA shows that there is significant difference between the FN and FD group in total reading score and global inference question. However, when the reading strategies have been partialled out of the correlations between cognitive style and reading scores, the remaining correlation with the total reading score and global inference and lexical inference reaches significance. This indicates the different information processing of FD/FI learners and the important role of direct reading strategies for all learners. Teachers can help their students become more effective readers by encouraging them to apply direct reading strategies, and apply different indirect reading strategies based on their different cognitive styles.