In order to improve the performance of voice conversion, the fundamental frequency (F0) transformation methods are investigated, and an efficient F0 transformation algorithm is proposed. First, unlike the traditiona...In order to improve the performance of voice conversion, the fundamental frequency (F0) transformation methods are investigated, and an efficient F0 transformation algorithm is proposed. First, unlike the traditional linear transformation methods, the relationships between F0s and spectral parameters are explored. In each component of the Gaussian mixture model (GMM), the F0s are predicted from the converted spectral parameters using the support vector regression (SVR) method. Then, in order to reduce the over- smoothing caused by the statistical average of the GMM, a mixed transformation method combining SVR with the traditional mean-variance linear (MVL) conversion is presented. Meanwhile, the adaptive median filter, prevalent in image processing, is adopted to solve the discontinuity problem caused by the frame-wise transformation. Objective and subjective experiments are carried out to evaluate the performance of the proposed method. The results demonstrate that the proposed method outperforms the traditional F0 transformation methods in terms of the similarity and the quality.展开更多
Spin-crossover (SCO) magnets can act as one of the most possible building blocks in molec- ular spintronics due to their magnetic bistability between the high-spin (HS) and low-spin (LS) states. Here, the electr...Spin-crossover (SCO) magnets can act as one of the most possible building blocks in molec- ular spintronics due to their magnetic bistability between the high-spin (HS) and low-spin (LS) states. Here, the electronic structures and transport properties through SCO magnet Fe(II)-N4S2 complexes sandwiched between gold electrodes are explored by performing exten- sive density functional theory calculations combined with non-equilibrium Green's function formalism. The optimized Fe-N and Fe-S distances and predicted magnetic moment of the SCO magnet Fe(II)-N4S2 complexes agree well with the experimental results. The reversed spin transition between the HS and LS states can be realized by visible light irradiation according to the estimated SCO energy barriers. Based on the obtained transport results, we observe nearly perfect spin-filtering effect in this SCO magnet Fe(II)-N4S2 junction with the HS state, and the corresponding current under small bias voltage is mainly contributed by the spin-down electrons, which is obviously larger than that of the LS case. Clearly, these theoretical findings suggest that SCO magnet Fe(II)-N4S2 complexes hold potential applications in molecular spintronies.展开更多
In the light of C-mapping method and topological current theory, the stability of disclinations around a spherical particle in nematic liquid crystals is studied. We consider two different defect structures around a s...In the light of C-mapping method and topological current theory, the stability of disclinations around a spherical particle in nematic liquid crystals is studied. We consider two different defect structures around a spherical particle: disclination ring and point defect at the north or south pole of the particle. We calculate the free energy of these different defects in the elastic theory. It is pointed out that the total Frank free energy density can be divided into two parts. One is the distorted energy density of director field around the disclinations. The other is the free energy density of disclinations themselves, which is shown to be concentrated at the defect and to be topologically quantized in the unit of (k - k24)π/2. It is shown that in the presence of saddle-splay elasticity a dipole (radial and hyperbolic hedgehog) configuration that accompanies a particle with strong homeotropic anchoring takes the structure of a small disclination ring, not a point defect.展开更多
A joint cooperation diversity and symbol mapping diversity (SMD) strategy is proposed for cooperative packet retransmission system with high-order modulation such as 16QAM. Substantial SER/BER (symbol error rate/bit e...A joint cooperation diversity and symbol mapping diversity (SMD) strategy is proposed for cooperative packet retransmission system with high-order modulation such as 16QAM. Substantial SER/BER (symbol error rate/bit error rate) gains result from multiple packet transmissions over independent paths and distinct bit-to-symbol mappings for each packet transmis-sion. The SER/BER performance of relay assisted retransmission system is analyzed. Simulation results show that the joint-diversity strategy can provide more BER gains than other relaying strategies (i.e., decode-and-forward and constellation rearrangement relaying strategies) when no relay makes a decision error; but if some relays make decision errors, the joint-di-versity strategy outperforms other relaying strategies only when the relays are closer to the source than to the destination.展开更多
AIM: To screen for genes related to metabotropic re- ceptors that might be involved in the development of chronic hepatitis. METHODS: Assessment of 20 genes associated with metabotropic receptors was performed in li...AIM: To screen for genes related to metabotropic re- ceptors that might be involved in the development of chronic hepatitis. METHODS: Assessment of 20 genes associated with metabotropic receptors was performed in liver speci- mens obtained by punch biopsy from 12 patients with autoimmune and chronic hepatitis type B and C. For this purpose, a microarray with low integrity grade and with oligonucleotide DNA probes complementary to target transcripts was used. Evaluation of gene expression was performed in relation to transcript level, correlation between samples and grouping of clinical parameters used in chronic hepatitis assessment. Clini- cal markers of chronic hepatitis included alanine and aspartate aminotransferase, ~,-glutamyltranspeptidase, alkaline phosphatase and cholinesterase activity, levels of iron ions, total cholesterol, triglycerides, albumin, glucose, hemoglobin, platelets, histological analysis of inflammatory and necrotic status, fibrosis according to METAVIR score, steatosis, as well as anthropometric body mass index, waist/hip index, percentage of adi- pose tissue and liver size in ultrasound examination. Gender, age, concomitant diseases and drugs were also taken into account. Validation of oligonucleotide microarray gene expression results was done with the use of quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: The highest (0.002 〈 P 〈 0.046) expres- sion among genes encoding main components of metabotropic receptor pathways, such as the a subunit of G-coupled protein, phosphoinositol-dependent pro- tein kinase or arrestin was comparable to that of an- giotensinogen synthesized in the liver. Carcinogenesis suppressor genes, such as chemokine ligand 4, tran- scription factor early growth response protein 1 and lysophosphatidic acid receptor, were characterized by the lowest expression (0.002 〈 P 〈 0.046), while the factor potentially triggering hepatic cancer, transcrip- tion factor JUN-B, had a 20-fold higher expression. The correlation between expression of genes of protein kinases PDPK1, phosphoinositide 3-kinase and protein kinase A (Spearman's coefficient range: 0.762-0.769) confirmed a functional link between these enzymes. Gender (P = 0.0046) and inflammation severity, mea- sured by alanine aminotransferase activity (P = 0.035), were characterized by diverse metabotropic receptor gene expression patterns. The Pearson's coefficient ranging from -0.35 to 0.99 from the results of qRT-PCR and microarray indicated that qRT-PCR had certainlimitations as a validation tool for oligonucleotide mi- croarray studies. CONCLUSION: A microarray-based analysis of hepa- tocyte metabotropic G-protein-related gene expression can reveal the molecular basis of chronic hepatitis.展开更多
Using the effective-field theory we studied the magnetic properties of a spin-1/2 Ising supedattice, which consist of three different ferromagnet materials. The magnetic behavior of this superlattice is examined. The ...Using the effective-field theory we studied the magnetic properties of a spin-1/2 Ising supedattice, which consist of three different ferromagnet materials. The magnetic behavior of this superlattice is examined. The critical temperature and the compensation temprature of the system are studied as a function of the exchange interactions between the nearest-neiboring spins across the interface and in the intraface. Temperature dependence of magenetizations is also given.展开更多
The cytokine-induced killer (CIK) therapy was an effective treatment for many cancers. We report a patient with postoperative rectal cancer received autologous CIK therapy combined with raltitrexed chemotherapy. After...The cytokine-induced killer (CIK) therapy was an effective treatment for many cancers. We report a patient with postoperative rectal cancer received autologous CIK therapy combined with raltitrexed chemotherapy. After the adjuvant therapy, the serum transaminase was persistently elevated, and lung metastases was observed. Due to hepatic injury, only cytokine-induced killer therapy was administered, and it rectified transaminase. The following regimens of CIK therapy and low-dose raltitrexed could diminish the metastatic lesion, improve the quality of life and prolong the survival time. It reveals that the CIK cells may repair the hepatic injury.展开更多
A fast automatic AC-DC switch is designed and fabricated mainly by a microcontroller and three double poles single throw reed relays.This new switch is introduced to establish a fully automated system for AC-DC measur...A fast automatic AC-DC switch is designed and fabricated mainly by a microcontroller and three double poles single throw reed relays.This new switch is introduced to establish a fully automated system for AC-DC measurements through ACDC transfer standards for the first time at the National Institute for standards(N IS)in Egypt.The implemented circuit of theautomatic AC-DC switch and its protection are presented in details.An AC voltage source is calibrated against DC voltagesource by using the demonstrated automatic switch as an application The calibrated voltage ranges are2V,6V,20V and60V as examples.The uncertainty budget is also evaluated for the calibrated values.展开更多
NIH 3T3 cells, a mouse fibroblast cell line used as routine target cells for transfection experiments, undergo spontaneous transformation in our experiments after they form a confluent sheet in medium containing fetal...NIH 3T3 cells, a mouse fibroblast cell line used as routine target cells for transfection experiments, undergo spontaneous transformation in our experiments after they form a confluent sheet in medium containing fetal bovina serum (FBS) or lower coneentrafcion of calf serum (CS). The transformation takes the form of foci of multiplying cells among the surrounding cells which have stopped cell division. However, no focus of transformed cells could be seen in medium containing high concentration (10%) of OS. Further experiments indicated that the frequency of transformation is highly dependent on the concentration of serum and the transformation in OS is changeable when the cells are passaged in FBS. 8H-thymidine autoradiography has been proved to be a sensitive measurement indicator for foous formation. Our results suggest that the high frequency of transformation and its dependence on confmenoy as well as on medium composition are characteristics of cell differentiation rather than mutation. The role of the NIH 3T3 cell line as a cancer-initiated cell population and its accelerated transformation by rat oncogene might be considered as a form of tumor promotion is discussed.展开更多
This paper devotes to rational design for the ship propellers with long wavy blades. Thin long blades create big elastic deformations, which can be a regulator of an optimum angle for attack. The wavy form provides st...This paper devotes to rational design for the ship propellers with long wavy blades. Thin long blades create big elastic deformations, which can be a regulator of an optimum angle for attack. The wavy form provides stability on operational modes. To ensure stabilization to decrease in bending and torsion fluctuations, the main sectorial coordinates were defined by combining the shift centre with the gravity centre for computer geometrical models of the rowing screw blade and an idealized elastic deformable boundary liquid flow layer while unit thickness was offered. More rational petal forms of the long blade with a wavy surface are explained for exception of not free torsion.展开更多
For evolutionary random excitations, a general method of analyzing nonstationary random responses of systems was presented in this paper. Firstly, for the evolutionary random excitation model, the evolutionary power s...For evolutionary random excitations, a general method of analyzing nonstationary random responses of systems was presented in this paper. Firstly, for the evolutionary random excitation model, the evolutionary power spectrum density function (EPSD) of a random excitation was given by wavelet transform. Based on the EPSD, the nonstationary responses of a SDOF system subjected to evolutionary random excitations were studied. The application and validity of presented method were illustrated by numerical examples. In numerical examples, the recently developed stochastic models for El Centro (1934) and Mexico City (1985) earthquakes which preserve the nonstationary evolutions of amplitude and frequency content of ground accelerations were used as excitations. The nonstationary random mean-square responses of a SDOF system under these two excitations were evaluated and compared with simulated results.展开更多
The article presents the results of experimental studies of the physical mechanisms and magnetic switching dynamics of films with one or two magnetic nanolayers under an irradiation picosecond and femtosecond laser pu...The article presents the results of experimental studies of the physical mechanisms and magnetic switching dynamics of films with one or two magnetic nanolayers under an irradiation picosecond and femtosecond laser pulses and also the samples of data recording devices on the spin storage medium are described. The study used a film with perpendicular anisotropy (Tb22Co5Fe73/Pr6O11/Tb29Co5Fe76, Tb25Co5Fe70/Al2O3, Tb22Co5Fe73, Tb19Co5Fe76) and films planar single-axis magnetic anisotropy (Co80Fe20/Pr6O11/CO30Fe70). The magnetic switching of magnetic layers under action the magnetic field of a spin current is the most important for practical use in elements of spintronic. The spin current can also be realized using short electrical pulses. On the basis of this mechanism, the high-speed recording of information on the spin carrier has been realized.展开更多
The flipped classroom is an emerging teaching mode which is originated from the United States and is now prevalent in many countries. It is helpful to build a more harmonious relationship between the teachers and the ...The flipped classroom is an emerging teaching mode which is originated from the United States and is now prevalent in many countries. It is helpful to build a more harmonious relationship between the teachers and the students, to enhance the students' self-study ability, to create a favorable learning environment, to realize the individualized teaching in class, and to improve the students' English ability. The study focuses on the college English classroom in China. The author tries to prove that the flipped classroom is a helpful way to improve the teaching and learning effect of college English classroom. A teaching procedure for the flipped college English classroom is designed in the hope of changing the current college English teaching condition.展开更多
In the present paper, initial-boundary value problem of plane stress state of micropolar theory of elasticity is considered for orthotropic material in the domain of thin rectangle. General hypotheses are formulated, ...In the present paper, initial-boundary value problem of plane stress state of micropolar theory of elasticity is considered for orthotropic material in the domain of thin rectangle. General hypotheses are formulated, which are the qualitative results of the asymptotic method of integration of the stated initial-boundary value problem. On the basis of the accepted hypotheses general applied one-dimensional models of dynamics of bending deformation of micropolar orthotropic elastic thin bars with free fields of displacements and rotations are constructed with and without consideration of shear deformations. With the help of the constructed models different dynamic problems of micropolar bars can be studied. Here concrete problems of free and forced vibrations of hinged supported micropolar orthotropic elastic thin bar are studied. Numerical analysis is done and specific features of dynamic characteristics of micropolar material are revealed. Particularly, it is shown that there is a frequency of vibrations of the micropolar bar that does not depend on bar sizes.展开更多
This paper discusses the selective feature of understanding. The process of understanding is in nature that of constructing meaning and obtaining information, meanwhile, to construct meaning is to integrate different ...This paper discusses the selective feature of understanding. The process of understanding is in nature that of constructing meaning and obtaining information, meanwhile, to construct meaning is to integrate different signs into a text by means of metaphor and metonymy and to naturalize the meaning of the text, which turns out to be a process of constant selection. In addition, the contextual factors such as different individuals or groups and different cultural backgrounds make the understanding process selective. The knowledge of the selective feature of understanding plays an important role in foreign language teaching, especially concerned with text reading, translation and intercultural communication.展开更多
We study the stable homotopy types of F_n^4(2)-polyhedra, i.e.,(n- 1)-connected, at most(n+ 4)-dimensional polyhedra with 2-torsion free homologies. We are able to classify the indecomposable F_n^4(2)-polyhedra. The p...We study the stable homotopy types of F_n^4(2)-polyhedra, i.e.,(n- 1)-connected, at most(n+ 4)-dimensional polyhedra with 2-torsion free homologies. We are able to classify the indecomposable F_n^4(2)-polyhedra. The proof relies on the matrix problem technique which was developed in the classification of representations of algebras and applied to homotopy theory by Baues and Drozd(1999, 2001, 2004).展开更多
基金The National Natural Science Foundation of China(No. 60975017)the Natural Science Foundation of Guangdong Province (No. 10252800001000001)the Natural Science Foundation of Higher Education Institutions of Jiangsu Province (No. 10KJB510005)
文摘In order to improve the performance of voice conversion, the fundamental frequency (F0) transformation methods are investigated, and an efficient F0 transformation algorithm is proposed. First, unlike the traditional linear transformation methods, the relationships between F0s and spectral parameters are explored. In each component of the Gaussian mixture model (GMM), the F0s are predicted from the converted spectral parameters using the support vector regression (SVR) method. Then, in order to reduce the over- smoothing caused by the statistical average of the GMM, a mixed transformation method combining SVR with the traditional mean-variance linear (MVL) conversion is presented. Meanwhile, the adaptive median filter, prevalent in image processing, is adopted to solve the discontinuity problem caused by the frame-wise transformation. Objective and subjective experiments are carried out to evaluate the performance of the proposed method. The results demonstrate that the proposed method outperforms the traditional F0 transformation methods in terms of the similarity and the quality.
基金supported by the National Natural Science Foundation of China(No.21473168 and No.11634011)the Innovative Program of Development Foundation of Hefei Center for Physical Science and Technology
文摘Spin-crossover (SCO) magnets can act as one of the most possible building blocks in molec- ular spintronics due to their magnetic bistability between the high-spin (HS) and low-spin (LS) states. Here, the electronic structures and transport properties through SCO magnet Fe(II)-N4S2 complexes sandwiched between gold electrodes are explored by performing exten- sive density functional theory calculations combined with non-equilibrium Green's function formalism. The optimized Fe-N and Fe-S distances and predicted magnetic moment of the SCO magnet Fe(II)-N4S2 complexes agree well with the experimental results. The reversed spin transition between the HS and LS states can be realized by visible light irradiation according to the estimated SCO energy barriers. Based on the obtained transport results, we observe nearly perfect spin-filtering effect in this SCO magnet Fe(II)-N4S2 junction with the HS state, and the corresponding current under small bias voltage is mainly contributed by the spin-down electrons, which is obviously larger than that of the LS case. Clearly, these theoretical findings suggest that SCO magnet Fe(II)-N4S2 complexes hold potential applications in molecular spintronies.
基金The project supported by the Natural Science Foundation of Shanghai Municipal Commission of Science and Technology under Grant No. 04ZR14059, National Natural Science Foundation of China under Grant No. 10447125, and the Shanghai Municipal Science and Technology Commission under Grant No. 04dz05905
文摘In the light of C-mapping method and topological current theory, the stability of disclinations around a spherical particle in nematic liquid crystals is studied. We consider two different defect structures around a spherical particle: disclination ring and point defect at the north or south pole of the particle. We calculate the free energy of these different defects in the elastic theory. It is pointed out that the total Frank free energy density can be divided into two parts. One is the distorted energy density of director field around the disclinations. The other is the free energy density of disclinations themselves, which is shown to be concentrated at the defect and to be topologically quantized in the unit of (k - k24)π/2. It is shown that in the presence of saddle-splay elasticity a dipole (radial and hyperbolic hedgehog) configuration that accompanies a particle with strong homeotropic anchoring takes the structure of a small disclination ring, not a point defect.
基金the National Natural Science Foundation of China (No. 60372107)the Natural Science Fund for Higher Educa-tion of Jiangsu Province, China (No. 06KJA51001)the Natural Science Fund of the Science and Technology Department of Jiangsu Province, China (No. BK2007729)
文摘A joint cooperation diversity and symbol mapping diversity (SMD) strategy is proposed for cooperative packet retransmission system with high-order modulation such as 16QAM. Substantial SER/BER (symbol error rate/bit error rate) gains result from multiple packet transmissions over independent paths and distinct bit-to-symbol mappings for each packet transmis-sion. The SER/BER performance of relay assisted retransmission system is analyzed. Simulation results show that the joint-diversity strategy can provide more BER gains than other relaying strategies (i.e., decode-and-forward and constellation rearrangement relaying strategies) when no relay makes a decision error; but if some relays make decision errors, the joint-di-versity strategy outperforms other relaying strategies only when the relays are closer to the source than to the destination.
文摘AIM: To screen for genes related to metabotropic re- ceptors that might be involved in the development of chronic hepatitis. METHODS: Assessment of 20 genes associated with metabotropic receptors was performed in liver speci- mens obtained by punch biopsy from 12 patients with autoimmune and chronic hepatitis type B and C. For this purpose, a microarray with low integrity grade and with oligonucleotide DNA probes complementary to target transcripts was used. Evaluation of gene expression was performed in relation to transcript level, correlation between samples and grouping of clinical parameters used in chronic hepatitis assessment. Clini- cal markers of chronic hepatitis included alanine and aspartate aminotransferase, ~,-glutamyltranspeptidase, alkaline phosphatase and cholinesterase activity, levels of iron ions, total cholesterol, triglycerides, albumin, glucose, hemoglobin, platelets, histological analysis of inflammatory and necrotic status, fibrosis according to METAVIR score, steatosis, as well as anthropometric body mass index, waist/hip index, percentage of adi- pose tissue and liver size in ultrasound examination. Gender, age, concomitant diseases and drugs were also taken into account. Validation of oligonucleotide microarray gene expression results was done with the use of quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: The highest (0.002 〈 P 〈 0.046) expres- sion among genes encoding main components of metabotropic receptor pathways, such as the a subunit of G-coupled protein, phosphoinositol-dependent pro- tein kinase or arrestin was comparable to that of an- giotensinogen synthesized in the liver. Carcinogenesis suppressor genes, such as chemokine ligand 4, tran- scription factor early growth response protein 1 and lysophosphatidic acid receptor, were characterized by the lowest expression (0.002 〈 P 〈 0.046), while the factor potentially triggering hepatic cancer, transcrip- tion factor JUN-B, had a 20-fold higher expression. The correlation between expression of genes of protein kinases PDPK1, phosphoinositide 3-kinase and protein kinase A (Spearman's coefficient range: 0.762-0.769) confirmed a functional link between these enzymes. Gender (P = 0.0046) and inflammation severity, mea- sured by alanine aminotransferase activity (P = 0.035), were characterized by diverse metabotropic receptor gene expression patterns. The Pearson's coefficient ranging from -0.35 to 0.99 from the results of qRT-PCR and microarray indicated that qRT-PCR had certainlimitations as a validation tool for oligonucleotide mi- croarray studies. CONCLUSION: A microarray-based analysis of hepa- tocyte metabotropic G-protein-related gene expression can reveal the molecular basis of chronic hepatitis.
基金The project supported by Shanghai Leading Academic Discipline Project under Grant No. T0104
文摘Using the effective-field theory we studied the magnetic properties of a spin-1/2 Ising supedattice, which consist of three different ferromagnet materials. The magnetic behavior of this superlattice is examined. The critical temperature and the compensation temprature of the system are studied as a function of the exchange interactions between the nearest-neiboring spins across the interface and in the intraface. Temperature dependence of magenetizations is also given.
文摘The cytokine-induced killer (CIK) therapy was an effective treatment for many cancers. We report a patient with postoperative rectal cancer received autologous CIK therapy combined with raltitrexed chemotherapy. After the adjuvant therapy, the serum transaminase was persistently elevated, and lung metastases was observed. Due to hepatic injury, only cytokine-induced killer therapy was administered, and it rectified transaminase. The following regimens of CIK therapy and low-dose raltitrexed could diminish the metastatic lesion, improve the quality of life and prolong the survival time. It reveals that the CIK cells may repair the hepatic injury.
文摘A fast automatic AC-DC switch is designed and fabricated mainly by a microcontroller and three double poles single throw reed relays.This new switch is introduced to establish a fully automated system for AC-DC measurements through ACDC transfer standards for the first time at the National Institute for standards(N IS)in Egypt.The implemented circuit of theautomatic AC-DC switch and its protection are presented in details.An AC voltage source is calibrated against DC voltagesource by using the demonstrated automatic switch as an application The calibrated voltage ranges are2V,6V,20V and60V as examples.The uncertainty budget is also evaluated for the calibrated values.
文摘NIH 3T3 cells, a mouse fibroblast cell line used as routine target cells for transfection experiments, undergo spontaneous transformation in our experiments after they form a confluent sheet in medium containing fetal bovina serum (FBS) or lower coneentrafcion of calf serum (CS). The transformation takes the form of foci of multiplying cells among the surrounding cells which have stopped cell division. However, no focus of transformed cells could be seen in medium containing high concentration (10%) of OS. Further experiments indicated that the frequency of transformation is highly dependent on the concentration of serum and the transformation in OS is changeable when the cells are passaged in FBS. 8H-thymidine autoradiography has been proved to be a sensitive measurement indicator for foous formation. Our results suggest that the high frequency of transformation and its dependence on confmenoy as well as on medium composition are characteristics of cell differentiation rather than mutation. The role of the NIH 3T3 cell line as a cancer-initiated cell population and its accelerated transformation by rat oncogene might be considered as a form of tumor promotion is discussed.
文摘This paper devotes to rational design for the ship propellers with long wavy blades. Thin long blades create big elastic deformations, which can be a regulator of an optimum angle for attack. The wavy form provides stability on operational modes. To ensure stabilization to decrease in bending and torsion fluctuations, the main sectorial coordinates were defined by combining the shift centre with the gravity centre for computer geometrical models of the rowing screw blade and an idealized elastic deformable boundary liquid flow layer while unit thickness was offered. More rational petal forms of the long blade with a wavy surface are explained for exception of not free torsion.
文摘For evolutionary random excitations, a general method of analyzing nonstationary random responses of systems was presented in this paper. Firstly, for the evolutionary random excitation model, the evolutionary power spectrum density function (EPSD) of a random excitation was given by wavelet transform. Based on the EPSD, the nonstationary responses of a SDOF system subjected to evolutionary random excitations were studied. The application and validity of presented method were illustrated by numerical examples. In numerical examples, the recently developed stochastic models for El Centro (1934) and Mexico City (1985) earthquakes which preserve the nonstationary evolutions of amplitude and frequency content of ground accelerations were used as excitations. The nonstationary random mean-square responses of a SDOF system under these two excitations were evaluated and compared with simulated results.
文摘The article presents the results of experimental studies of the physical mechanisms and magnetic switching dynamics of films with one or two magnetic nanolayers under an irradiation picosecond and femtosecond laser pulses and also the samples of data recording devices on the spin storage medium are described. The study used a film with perpendicular anisotropy (Tb22Co5Fe73/Pr6O11/Tb29Co5Fe76, Tb25Co5Fe70/Al2O3, Tb22Co5Fe73, Tb19Co5Fe76) and films planar single-axis magnetic anisotropy (Co80Fe20/Pr6O11/CO30Fe70). The magnetic switching of magnetic layers under action the magnetic field of a spin current is the most important for practical use in elements of spintronic. The spin current can also be realized using short electrical pulses. On the basis of this mechanism, the high-speed recording of information on the spin carrier has been realized.
文摘The flipped classroom is an emerging teaching mode which is originated from the United States and is now prevalent in many countries. It is helpful to build a more harmonious relationship between the teachers and the students, to enhance the students' self-study ability, to create a favorable learning environment, to realize the individualized teaching in class, and to improve the students' English ability. The study focuses on the college English classroom in China. The author tries to prove that the flipped classroom is a helpful way to improve the teaching and learning effect of college English classroom. A teaching procedure for the flipped college English classroom is designed in the hope of changing the current college English teaching condition.
文摘In the present paper, initial-boundary value problem of plane stress state of micropolar theory of elasticity is considered for orthotropic material in the domain of thin rectangle. General hypotheses are formulated, which are the qualitative results of the asymptotic method of integration of the stated initial-boundary value problem. On the basis of the accepted hypotheses general applied one-dimensional models of dynamics of bending deformation of micropolar orthotropic elastic thin bars with free fields of displacements and rotations are constructed with and without consideration of shear deformations. With the help of the constructed models different dynamic problems of micropolar bars can be studied. Here concrete problems of free and forced vibrations of hinged supported micropolar orthotropic elastic thin bar are studied. Numerical analysis is done and specific features of dynamic characteristics of micropolar material are revealed. Particularly, it is shown that there is a frequency of vibrations of the micropolar bar that does not depend on bar sizes.
文摘This paper discusses the selective feature of understanding. The process of understanding is in nature that of constructing meaning and obtaining information, meanwhile, to construct meaning is to integrate different signs into a text by means of metaphor and metonymy and to naturalize the meaning of the text, which turns out to be a process of constant selection. In addition, the contextual factors such as different individuals or groups and different cultural backgrounds make the understanding process selective. The knowledge of the selective feature of understanding plays an important role in foreign language teaching, especially concerned with text reading, translation and intercultural communication.
基金supported by National Natural Science Foundation of China(Grant Nos.11131008 and 61173009)
文摘We study the stable homotopy types of F_n^4(2)-polyhedra, i.e.,(n- 1)-connected, at most(n+ 4)-dimensional polyhedra with 2-torsion free homologies. We are able to classify the indecomposable F_n^4(2)-polyhedra. The proof relies on the matrix problem technique which was developed in the classification of representations of algebras and applied to homotopy theory by Baues and Drozd(1999, 2001, 2004).