In order to increase the hardware utilization and minimize the chip area a multi-transform coding architecture which includes 4 ×4 forward integer transform 4 ×4 inverse integer transform 4 ×4 Hadamard ...In order to increase the hardware utilization and minimize the chip area a multi-transform coding architecture which includes 4 ×4 forward integer transform 4 ×4 inverse integer transform 4 ×4 Hadamard transform and 2 ×2 Hadamard transform is proposed. By simplifying these transforms and exploring their similarities the proposed design merges the architectures processing individual transforms into a high-performance multi-transform coding architecture.Using a semiconductor manufacturing international corporation SMIC 0.18 μm complementary metal oxide semiconductor CMOS technology the proposed architecture achieves the maximum operating clock frequency of 200 MHz and the throughput rate of 800 ×106 pixel/s with the hardware cost of 3 704 gates.The results demonstrate that the data throughput rate per unit area DTUA of this design is at least 40.28%higher than that of the reference design.This design can meet the requirements of real-time decoding digital cinema video 4 096 ×2 048@30 Hz at 62.9 MHz which helps to reduce the power consumption.展开更多
We show that the recently proposed invariant eigen-operator (IEO) method can be successfully applied to solving energy levels for SSH Hamiltonian describing Peierls phase transition. The electronic energy band of co...We show that the recently proposed invariant eigen-operator (IEO) method can be successfully applied to solving energy levels for SSH Hamiltonian describing Peierls phase transition. The electronic energy band of compound lattice is also studied by IEO method.展开更多
We consider the weighted composition operators between Hardy spaces on the unit ball, and obtain some sufficient and necessary conditions of bounded or compact weighted composition operators. We also prove that the op...We consider the weighted composition operators between Hardy spaces on the unit ball, and obtain some sufficient and necessary conditions of bounded or compact weighted composition operators. We also prove that the operator from H^1 to H^1 is compact if and only if it is weakly compact. Meanwhile, we get the analogue on the Bergman spaces.展开更多
This article proposes a new transceiver design for Single carrier frequency division multiple access(SCFDMA)system based on discrete wavelet transform(DWT). SCFDMA offers almost same structure as Orthogonal frequency ...This article proposes a new transceiver design for Single carrier frequency division multiple access(SCFDMA)system based on discrete wavelet transform(DWT). SCFDMA offers almost same structure as Orthogonal frequency division multiple access(OFDMA)with extra advantage of low Peak to Average Power Ratio(PAPR). Moreover,this article also suggests the application of Walsh Hadamard transform(WHT)for linear precoding(LP)to improve the PAPR performance of the system. Supremacy of the proposed transceiver over conventional Fast Fourier transform(FFT)based SCFDMA is shown through simulated results in terms of PAPR,spectral efficiency(SE)and bit error rate(BER).展开更多
One-dimensional generalized Boussinesq equation u tt-u xx+(f(u)+u xx)xx=0.with periodic boundary condition is considered, where f(u) = u3. First, the above equation is written as a Hamiltonian system, and then...One-dimensional generalized Boussinesq equation u tt-u xx+(f(u)+u xx)xx=0.with periodic boundary condition is considered, where f(u) = u3. First, the above equation is written as a Hamiltonian system, and then by choosing the eigenfunctions of the linear operator as bases, the Hamiltonian system in the coordinates is expressed. Because of the intricate resonance between the tangential frequencies and normal frequencies, some quasi-periodic solutions with special structures are considered. Secondly, the regularity of the Hamiltonian vector field is verified and then the fourth-order terms are normalized. By the Birkhoff normal form, the non- degeneracy and non-resonance conditions are obtained. Applying the infinite dimensional Kolmogorov-Arnold-Moser (KAM) theorem, the existence of finite dimensional invariant tori for the equivalent Hamiltonian system is proved. Hence many small-amplitude quasi-periodic solutions for the above equation are obtained.展开更多
The exact short time propagator, in a form similar to the Crank-Nicholson method but in the spirit of spectrally transformed Hamiltonian, was proposed to solve the triatomic reactive time-dependent schrodinger equatio...The exact short time propagator, in a form similar to the Crank-Nicholson method but in the spirit of spectrally transformed Hamiltonian, was proposed to solve the triatomic reactive time-dependent schrodinger equation. This new propagator is exact and unconditionally convergent for calculating reactive scattering processes with large time step sizes. In order to improve the computational efficiency, the spectral difference method was applied. This resulted the Hamiltonian with elements confined in a narrow diagonal band. In contrast to our previous theoretical work, the discrete variable representation was applied and resulted in full Hamiltonian matrix. As examples, the collision energy-dependent probability of the triatomic H+H2 and O+O2 reaction are calculated. The numerical results demonstrate that this new propagator is numerically accurate and capable of propagating the wave packet with large time steps. However, the efficiency and accuracy of this new propagator strongly depend on the mathematical method for solving the involved linear equations and the choice of preconditioner.展开更多
We study both classical and quantum relation between two Hamiltonian systems which are mutually connected by time-dependent canonical transformation. One is ordinary conservative system and the other is timedependent ...We study both classical and quantum relation between two Hamiltonian systems which are mutually connected by time-dependent canonical transformation. One is ordinary conservative system and the other is timedependent Hamiltonian system. The quantum unitary operator relevant to classical canonical transformation between the two systems are obtained through rigorous evaluation. With the aid of the unitary operator, we have derived quantum states of the time-dependent Hamiltonian system through transforming the quantum states of the conservative system. The invariant operators of the two systems are presented and the relation between them are addressed. We showed that there exist numerous Hamiltonians, which gives the same classical equation of motion. Though it is impossible to distinguish the systems described by these Hamiltonians within the realm of classical mechanics, they can be distinguishable quantum mechanically.展开更多
Based on sounding data from 1975 to 2005 and TM/ETM+ remote sensing images in 1989, 2001 and 2007, the climate changes in Harbin City, Northeast China in recent 30 years were analyzed and forecasted. Results show that...Based on sounding data from 1975 to 2005 and TM/ETM+ remote sensing images in 1989, 2001 and 2007, the climate changes in Harbin City, Northeast China in recent 30 years were analyzed and forecasted. Results show that in the lower troposphere the meridional wind speed and mean annual wind speed decrease, and in the lower stratosphere the temperature decreases while the meridional wind speed increases significantly. In the study area, the climate is becoming warmer and wetter in the middle lower troposphere. The expansion of urban area has great effects on the surface air temperature and the wind speed, leading to the increase of the surface air temperature, the decrease of the surface wind speed, and the increase of the area of urban high temperature zone. The quantitative equations have been established among the surface air temperature, the carbon dioxide (CO2) concentration and the specific humidity (the water vapor content). It is predicted that the future increasing rate of the surface air temperature is 0.85℃/10yr if emission concentration of CO2 remains unchanged; if emission concentration of CO2 decreases to 75%, 50% and 25%, respectively, the surface air temperature will increase 0.65℃/10yr, 0.46℃/10yr and 0.27℃/10yr, respectively. The rise of the surface air temperature in the study area is higher than that of the global mean temperature forecasted by IPCC.展开更多
Considering full perturbation to infinitesimal generators in the Mei structure equation,a new type of Meiadiabatic invariant induced by perturbation to Mei symmetry for Hamiltonian system was reported.
By using Gumming (JC) model. energy-level gap of this the pseudo invariant eigen-operator method we The pseudo-invariant eigen-operator is found in JC Hamiltonian is derived. This approach seems analyze the field-in...By using Gumming (JC) model. energy-level gap of this the pseudo invariant eigen-operator method we The pseudo-invariant eigen-operator is found in JC Hamiltonian is derived. This approach seems analyze the field-intensity-dependent Jaynes terms of the supersymmetric generators. The concise.展开更多
The central structure belt in Turpan-Hami basin is composed of the Huoyanshan structure and Qiketai structure formed in late Triassic-early Jurassic, and is characterized by extensional tectonics. The thickness of str...The central structure belt in Turpan-Hami basin is composed of the Huoyanshan structure and Qiketai structure formed in late Triassic-early Jurassic, and is characterized by extensional tectonics. The thickness of strata in the hanging wall of the growth fault is obviously larger than that in the footwall,and a deposition center was evolved in the Taibei sag where the hanging wall of the fault is located. In late Jurassic the collision between Lhasa block and Eurasia continent resulted in the transformation of the Turpan-Hami basin from an extensional structure into a compressional structure, and consequently in the tectonic inversion of the central structure belt of the Turpan-Hami basin from the extensional normal fault in the earlier stage to the compressive thrust fault in the later stage. The Tertiary collision between the Indian plate and the Eurasian plate occurred around 55Ma, and this Himalayan orogenic event has played a profound role in shaping the Tianshan area, only the effect of the collision to this area was delayed since it culminated here approximately in late Oligocene-early Miocene. The central structure belt was strongly deformed and thrusted above the ground as a result of this tectonic event.展开更多
In quantum calculations a transformed Hamiltonian is often used to avoid singularities in a certain basis set or to reduce computation time. We demonstrate for the Fourier basis set that the Hamiltonian can not be arb...In quantum calculations a transformed Hamiltonian is often used to avoid singularities in a certain basis set or to reduce computation time. We demonstrate for the Fourier basis set that the Hamiltonian can not be arbitrarily transformed. Otherwise, the Hamiltonian matrix becomes non-hermitian, which may lead to numerical problems. Methods for cor- rectly constructing the Hamiltonian operators are discussed. Specific examples involving the Fourier basis functions for a triatomic molecular Hamiltonian (J=0) in bond-bond angle and Radau coordinates are presented. For illustration, absorption spectra are calculated for the OC10 molecule using the time-dependent wavepacket method. Numerical results indicate that the non-hermiticity of the Hamiltonian matrix may also result from integration errors. The conclusion drawn here is generally useful for quantum calculation using basis expansion method using quadrature scheme.展开更多
As one of the most important steps in the design of bearing-less rotor systems,the design of flexible beam has received much research attention.Because of the very complex working environment of helicopter,the flexibl...As one of the most important steps in the design of bearing-less rotor systems,the design of flexible beam has received much research attention.Because of the very complex working environment of helicopter,the flexible beam should satisfy both the strength and dynamic requirements.However,traditional optimization research focused only on either the strength or dynamical characteristics.To sufficiently improve the performance of the flexible beam,both aspects must be considered.This paper proposes a two-stage optimization method based on the Hamilton variational principle:Variational asymptotic beam section analysis(VABS)program and genetic algorithm(GA).Consequently,a two-part analysis model based on the Hamilton variational principle and VABS is established to calculate section characteristics and structural dynamics characteristics,respectively.Subsequently,the two parts are combined to establish a two-stage optimization process and search with GA to obtain the best dynamic characteristics combinations.Based on the primary optimization results,the section characteristics of the flexible beam are further optimized using GA.The optimization results show that the torsional stiffness decreases by 36.1%compared with the full 0°laying scheme without optimization and the dynamic requirements are achieved.The natural frequencies of flapping and torsion meet the requirements(0.5 away from the passing frequencies of the blade,0.25 away from the excitation force frequency,and the flapping and torsion frequencies keep a corresponding distance).The results indicate that the optimization method can significantly improve the performance of the flexible beam.展开更多
Global environmental meeting, legislating a reduction in the emission of greenhouse gases for planet earth, is what mankind now hopes for, having realized the enormous dangers in the process of climate change. Global ...Global environmental meeting, legislating a reduction in the emission of greenhouse gases for planet earth, is what mankind now hopes for, having realized the enormous dangers in the process of climate change. Global warming is no longer denied by the so-called cornucopians (e.g. Lomberg), but global policy-making originating in reunions of 190 governments or more stumble on collective action difficulties, spelled out in game theory. Paris will not succeed where Copenhagen failed, namely to arrive at a binding and enforceable global environment policy that will be implemented before it is too late. Instead, there will be massive transaction costs from negotiating and re-negotiating, endless voting, the making of promises exante and reneging ex post, as well as the futile attempts at any enforcement action, given state sovereignty. Mankind will have to learn how to cope with the outcomes of global warming, as resilience is the only hope.展开更多
The phenomenological non-relativistic quark model (NRQM) has been employed to obtain the masses of bottomonium states. In the frame work of NRQM an exhaustive study of radiative and leptonic decays has been made. Th...The phenomenological non-relativistic quark model (NRQM) has been employed to obtain the masses of bottomonium states. In the frame work of NRQM an exhaustive study of radiative and leptonic decays has been made. The Hamiltonian used in the investigation has kinetic energy, confinement potentiM and one gluon exchange potential (OGEP). An overall agreement is obtained with the experimental masses and decay widths.展开更多
Objective The aims of the present study were to investigate the associations of 46 A〉G, 79 C〉G, 491 C〉T and 659 C〉G genetic variants of the human beta 2-adrenergic receptor (β2-AR), ADRB2, gene with essential h...Objective The aims of the present study were to investigate the associations of 46 A〉G, 79 C〉G, 491 C〉T and 659 C〉G genetic variants of the human beta 2-adrenergic receptor (β2-AR), ADRB2, gene with essential hypertension (EH) in Xinjiang Kazakans population.Methods A gender-matched case-control (271 hypertensive cases and 267 normotensive controls) study was used to investigate the associations of the four variations in the coding region of ADRB2 with EH. The genotypes of the variants were identified by the polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) methods. Results 46 A〉G, 79 C〉G and 659 C〉G polymorphisms were common in the Kazakan population, but 491 C〉T was a mutation (frequency ofT allele was only 0.003) and only found in EH group. The fxequency distributions of genotypes and alleles for 659 C〉G between the EH and control groups was significantly different (P〈0.05), while those for 46 A〉G and 79 C〉G polymorphisms were not statistically different. Logistic regression analysis suggested that the G allele of 659 C〉G polymorphism was a risk factor for hypertension (minor allele vs common homo; odds ratio, 13.240, 95% CI, 4.052-43.274; P〈0.05). Covariance analysis showed that systolic and diastolic blood pressure levels in GG+CG group of 659 C〉G were significantly higher than those in the CC group, but no significant difference of blood pressure were found between common homo and minor allele for 46 A〉G and 79C〉G polymorphisms. Haplotype analysis showed that two hyplotypes, HI: 46A-79C-491C-523C(48%)and H5:46A-79C-491C-659G, were associated with EH.Conelusion ADRB2 genetic variants may play independent roles in the molecular genetic mechanism of EH in Xinjiang Kazakans population (d Geriatr Cardio12010; 7:52-57).展开更多
The critical behaviors of a mixed spin-1/2 and spin-sB Ising system with a transverse crystal field are studiedby use of the effective-field theory with correlations. The effect of the transverse crystal field on tran...The critical behaviors of a mixed spin-1/2 and spin-sB Ising system with a transverse crystal field are studiedby use of the effective-field theory with correlations. The effect of the transverse crystal field on transition temperaturesis investigated numerically for the honeycomb (z = 3) and square (z = 4) lattices. The results show that there is notricritical point for the system.展开更多
基金The National Key Technology R&D Program of China during the 12th Five Year Plan Period(No.2013BAJ05B03)
文摘In order to increase the hardware utilization and minimize the chip area a multi-transform coding architecture which includes 4 ×4 forward integer transform 4 ×4 inverse integer transform 4 ×4 Hadamard transform and 2 ×2 Hadamard transform is proposed. By simplifying these transforms and exploring their similarities the proposed design merges the architectures processing individual transforms into a high-performance multi-transform coding architecture.Using a semiconductor manufacturing international corporation SMIC 0.18 μm complementary metal oxide semiconductor CMOS technology the proposed architecture achieves the maximum operating clock frequency of 200 MHz and the throughput rate of 800 ×106 pixel/s with the hardware cost of 3 704 gates.The results demonstrate that the data throughput rate per unit area DTUA of this design is at least 40.28%higher than that of the reference design.This design can meet the requirements of real-time decoding digital cinema video 4 096 ×2 048@30 Hz at 62.9 MHz which helps to reduce the power consumption.
基金supported by the President Foundation of the Chinese Academy of Sciences and National Natural Science Foundation of China under Grant No.10475657
文摘We show that the recently proposed invariant eigen-operator (IEO) method can be successfully applied to solving energy levels for SSH Hamiltonian describing Peierls phase transition. The electronic energy band of compound lattice is also studied by IEO method.
基金Supported in part by 973 plan and NSF of Zhejiang Province of China(Gl999075105)
文摘We consider the weighted composition operators between Hardy spaces on the unit ball, and obtain some sufficient and necessary conditions of bounded or compact weighted composition operators. We also prove that the operator from H^1 to H^1 is compact if and only if it is weakly compact. Meanwhile, we get the analogue on the Bergman spaces.
文摘This article proposes a new transceiver design for Single carrier frequency division multiple access(SCFDMA)system based on discrete wavelet transform(DWT). SCFDMA offers almost same structure as Orthogonal frequency division multiple access(OFDMA)with extra advantage of low Peak to Average Power Ratio(PAPR). Moreover,this article also suggests the application of Walsh Hadamard transform(WHT)for linear precoding(LP)to improve the PAPR performance of the system. Supremacy of the proposed transceiver over conventional Fast Fourier transform(FFT)based SCFDMA is shown through simulated results in terms of PAPR,spectral efficiency(SE)and bit error rate(BER).
基金The National Natural Science Foundation of China(No.11301072)the Natural Science Foundation of Jiangsu Province(No.BK20131285)the Research and Innovation Project for College Graduates of Jiangsu Province(No.CXZZ12-0083,CXLX13-074)
文摘One-dimensional generalized Boussinesq equation u tt-u xx+(f(u)+u xx)xx=0.with periodic boundary condition is considered, where f(u) = u3. First, the above equation is written as a Hamiltonian system, and then by choosing the eigenfunctions of the linear operator as bases, the Hamiltonian system in the coordinates is expressed. Because of the intricate resonance between the tangential frequencies and normal frequencies, some quasi-periodic solutions with special structures are considered. Secondly, the regularity of the Hamiltonian vector field is verified and then the fourth-order terms are normalized. By the Birkhoff normal form, the non- degeneracy and non-resonance conditions are obtained. Applying the infinite dimensional Kolmogorov-Arnold-Moser (KAM) theorem, the existence of finite dimensional invariant tori for the equivalent Hamiltonian system is proved. Hence many small-amplitude quasi-periodic solutions for the above equation are obtained.
文摘The exact short time propagator, in a form similar to the Crank-Nicholson method but in the spirit of spectrally transformed Hamiltonian, was proposed to solve the triatomic reactive time-dependent schrodinger equation. This new propagator is exact and unconditionally convergent for calculating reactive scattering processes with large time step sizes. In order to improve the computational efficiency, the spectral difference method was applied. This resulted the Hamiltonian with elements confined in a narrow diagonal band. In contrast to our previous theoretical work, the discrete variable representation was applied and resulted in full Hamiltonian matrix. As examples, the collision energy-dependent probability of the triatomic H+H2 and O+O2 reaction are calculated. The numerical results demonstrate that this new propagator is numerically accurate and capable of propagating the wave packet with large time steps. However, the efficiency and accuracy of this new propagator strongly depend on the mathematical method for solving the involved linear equations and the choice of preconditioner.
基金Supported by the Korea Science and Engineering Foundation (KOSEF) Grant Funded by the Korea Government (MOST) under Grant No.F01-2007-000-10075-0
文摘We study both classical and quantum relation between two Hamiltonian systems which are mutually connected by time-dependent canonical transformation. One is ordinary conservative system and the other is timedependent Hamiltonian system. The quantum unitary operator relevant to classical canonical transformation between the two systems are obtained through rigorous evaluation. With the aid of the unitary operator, we have derived quantum states of the time-dependent Hamiltonian system through transforming the quantum states of the conservative system. The invariant operators of the two systems are presented and the relation between them are addressed. We showed that there exist numerous Hamiltonians, which gives the same classical equation of motion. Though it is impossible to distinguish the systems described by these Hamiltonians within the realm of classical mechanics, they can be distinguishable quantum mechanically.
基金Under the auspices of Major State Basic Research Development Program of China (No. 2010CB950900)Technology Innovation Program of Harbin City (No. 2007RFXXS029)
文摘Based on sounding data from 1975 to 2005 and TM/ETM+ remote sensing images in 1989, 2001 and 2007, the climate changes in Harbin City, Northeast China in recent 30 years were analyzed and forecasted. Results show that in the lower troposphere the meridional wind speed and mean annual wind speed decrease, and in the lower stratosphere the temperature decreases while the meridional wind speed increases significantly. In the study area, the climate is becoming warmer and wetter in the middle lower troposphere. The expansion of urban area has great effects on the surface air temperature and the wind speed, leading to the increase of the surface air temperature, the decrease of the surface wind speed, and the increase of the area of urban high temperature zone. The quantitative equations have been established among the surface air temperature, the carbon dioxide (CO2) concentration and the specific humidity (the water vapor content). It is predicted that the future increasing rate of the surface air temperature is 0.85℃/10yr if emission concentration of CO2 remains unchanged; if emission concentration of CO2 decreases to 75%, 50% and 25%, respectively, the surface air temperature will increase 0.65℃/10yr, 0.46℃/10yr and 0.27℃/10yr, respectively. The rise of the surface air temperature in the study area is higher than that of the global mean temperature forecasted by IPCC.
基金Supported by the Natural Science Foundation of Shandong Province under Grant No.Y2008A33
文摘Considering full perturbation to infinitesimal generators in the Mei structure equation,a new type of Meiadiabatic invariant induced by perturbation to Mei symmetry for Hamiltonian system was reported.
基金Supported by Foundation of President of Chinese Academy of Science
文摘By using Gumming (JC) model. energy-level gap of this the pseudo invariant eigen-operator method we The pseudo-invariant eigen-operator is found in JC Hamiltonian is derived. This approach seems analyze the field-intensity-dependent Jaynes terms of the supersymmetric generators. The concise.
文摘The central structure belt in Turpan-Hami basin is composed of the Huoyanshan structure and Qiketai structure formed in late Triassic-early Jurassic, and is characterized by extensional tectonics. The thickness of strata in the hanging wall of the growth fault is obviously larger than that in the footwall,and a deposition center was evolved in the Taibei sag where the hanging wall of the fault is located. In late Jurassic the collision between Lhasa block and Eurasia continent resulted in the transformation of the Turpan-Hami basin from an extensional structure into a compressional structure, and consequently in the tectonic inversion of the central structure belt of the Turpan-Hami basin from the extensional normal fault in the earlier stage to the compressive thrust fault in the later stage. The Tertiary collision between the Indian plate and the Eurasian plate occurred around 55Ma, and this Himalayan orogenic event has played a profound role in shaping the Tianshan area, only the effect of the collision to this area was delayed since it culminated here approximately in late Oligocene-early Miocene. The central structure belt was strongly deformed and thrusted above the ground as a result of this tectonic event.
基金This work was supported by the National Basic Research Program of China (No.2013CB922200), the National Natural Science Foundation of China (No.21222308, No.21103187, and No.21133006), the Chinese Academy of Sciences, and the Key Research Program of the Chinese Academy of Sciences.
文摘In quantum calculations a transformed Hamiltonian is often used to avoid singularities in a certain basis set or to reduce computation time. We demonstrate for the Fourier basis set that the Hamiltonian can not be arbitrarily transformed. Otherwise, the Hamiltonian matrix becomes non-hermitian, which may lead to numerical problems. Methods for cor- rectly constructing the Hamiltonian operators are discussed. Specific examples involving the Fourier basis functions for a triatomic molecular Hamiltonian (J=0) in bond-bond angle and Radau coordinates are presented. For illustration, absorption spectra are calculated for the OC10 molecule using the time-dependent wavepacket method. Numerical results indicate that the non-hermiticity of the Hamiltonian matrix may also result from integration errors. The conclusion drawn here is generally useful for quantum calculation using basis expansion method using quadrature scheme.
基金supported by the Foundation of National Key Laboratory of Rotorcraft Aeromechanics,Nanjing University of Aeronautics and Astronautics(No.614222004030917)。
文摘As one of the most important steps in the design of bearing-less rotor systems,the design of flexible beam has received much research attention.Because of the very complex working environment of helicopter,the flexible beam should satisfy both the strength and dynamic requirements.However,traditional optimization research focused only on either the strength or dynamical characteristics.To sufficiently improve the performance of the flexible beam,both aspects must be considered.This paper proposes a two-stage optimization method based on the Hamilton variational principle:Variational asymptotic beam section analysis(VABS)program and genetic algorithm(GA).Consequently,a two-part analysis model based on the Hamilton variational principle and VABS is established to calculate section characteristics and structural dynamics characteristics,respectively.Subsequently,the two parts are combined to establish a two-stage optimization process and search with GA to obtain the best dynamic characteristics combinations.Based on the primary optimization results,the section characteristics of the flexible beam are further optimized using GA.The optimization results show that the torsional stiffness decreases by 36.1%compared with the full 0°laying scheme without optimization and the dynamic requirements are achieved.The natural frequencies of flapping and torsion meet the requirements(0.5 away from the passing frequencies of the blade,0.25 away from the excitation force frequency,and the flapping and torsion frequencies keep a corresponding distance).The results indicate that the optimization method can significantly improve the performance of the flexible beam.
文摘Global environmental meeting, legislating a reduction in the emission of greenhouse gases for planet earth, is what mankind now hopes for, having realized the enormous dangers in the process of climate change. Global warming is no longer denied by the so-called cornucopians (e.g. Lomberg), but global policy-making originating in reunions of 190 governments or more stumble on collective action difficulties, spelled out in game theory. Paris will not succeed where Copenhagen failed, namely to arrive at a binding and enforceable global environment policy that will be implemented before it is too late. Instead, there will be massive transaction costs from negotiating and re-negotiating, endless voting, the making of promises exante and reneging ex post, as well as the futile attempts at any enforcement action, given state sovereignty. Mankind will have to learn how to cope with the outcomes of global warming, as resilience is the only hope.
文摘The phenomenological non-relativistic quark model (NRQM) has been employed to obtain the masses of bottomonium states. In the frame work of NRQM an exhaustive study of radiative and leptonic decays has been made. The Hamiltonian used in the investigation has kinetic energy, confinement potentiM and one gluon exchange potential (OGEP). An overall agreement is obtained with the experimental masses and decay widths.
文摘Objective The aims of the present study were to investigate the associations of 46 A〉G, 79 C〉G, 491 C〉T and 659 C〉G genetic variants of the human beta 2-adrenergic receptor (β2-AR), ADRB2, gene with essential hypertension (EH) in Xinjiang Kazakans population.Methods A gender-matched case-control (271 hypertensive cases and 267 normotensive controls) study was used to investigate the associations of the four variations in the coding region of ADRB2 with EH. The genotypes of the variants were identified by the polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) methods. Results 46 A〉G, 79 C〉G and 659 C〉G polymorphisms were common in the Kazakan population, but 491 C〉T was a mutation (frequency ofT allele was only 0.003) and only found in EH group. The fxequency distributions of genotypes and alleles for 659 C〉G between the EH and control groups was significantly different (P〈0.05), while those for 46 A〉G and 79 C〉G polymorphisms were not statistically different. Logistic regression analysis suggested that the G allele of 659 C〉G polymorphism was a risk factor for hypertension (minor allele vs common homo; odds ratio, 13.240, 95% CI, 4.052-43.274; P〈0.05). Covariance analysis showed that systolic and diastolic blood pressure levels in GG+CG group of 659 C〉G were significantly higher than those in the CC group, but no significant difference of blood pressure were found between common homo and minor allele for 46 A〉G and 79C〉G polymorphisms. Haplotype analysis showed that two hyplotypes, HI: 46A-79C-491C-523C(48%)and H5:46A-79C-491C-659G, were associated with EH.Conelusion ADRB2 genetic variants may play independent roles in the molecular genetic mechanism of EH in Xinjiang Kazakans population (d Geriatr Cardio12010; 7:52-57).
基金The project supported by Science Foundation of the Ministry of Education of China under Grant No.99026
文摘The critical behaviors of a mixed spin-1/2 and spin-sB Ising system with a transverse crystal field are studiedby use of the effective-field theory with correlations. The effect of the transverse crystal field on transition temperaturesis investigated numerically for the honeycomb (z = 3) and square (z = 4) lattices. The results show that there is notricritical point for the system.