Several important factors affecting the efficiency of Agrobacterium-mediated rice transformation were studied with several predominant commercial indica and japonica rice cultivars. As far as indica rice callus was co...Several important factors affecting the efficiency of Agrobacterium-mediated rice transformation were studied with several predominant commercial indica and japonica rice cultivars. As far as indica rice callus was concerned, CC medium was the best and the quality of callus was improved with the addition of 1.0 to 2.0 mg/L ABA. It decreased the percentage of browning calli and improved the callus growing state by addition of a certain amount of sorbitol to the subculture medium. NB medium was the best for callus initiation of japonica rice, but the improvement in the quality of callus of japonica subspecies was not obvious by adding ABA. During the period of subculture, to a certain degree, increasing the sucrose concentration could improve the proportion of hygromycin resistant calli. Furthermore, the transformation efficiency would be higher by applying selection pressure in the selection stage, removing selection pressure during the plantlet differentiation period and applying selection pressure again during seedling hardening period. Besides, suitable combination of plant hormones was beneficial for callus differentiation. An efficient /Agrobacterium-mediated rice transformation system had been established for several rice cultivars and a lot of transgenic rice plants had been obtained.展开更多
Effects of hypobaric storage on physiological and biochemical changes in Dong jujube fruit were investigated. Hypobaric storage significantly delayed the decrease in firmness and maintained content of ascorbic acid, r...Effects of hypobaric storage on physiological and biochemical changes in Dong jujube fruit were investigated. Hypobaric storage significantly delayed the decrease in firmness and maintained content of ascorbic acid, reduced accumulation of ethanol and acetaldehyde in pulp and respiration, inhibited activities of ascorbic acid oxidase and alcohol dehydrogenase and slowed down the rate of ethylene production, but had little effect on flesh browning of the fruit.展开更多
The aim of this paper is to derive the power law type nonlinear viscoelastic crack-tip fields.For the requirement of later derivation,the HRR singular fields and the high-order asymp- totic fields are first examined.T...The aim of this paper is to derive the power law type nonlinear viscoelastic crack-tip fields.For the requirement of later derivation,the HRR singular fields and the high-order asymp- totic fields are first examined.That they are essentially the isotropic,incompressible,power law type nonlinear elastic crack-tip fields is illustrated.After a concise review of the elasticity recov- ery correspondence principle for solving the nonlinear viscoelastic problems,the correspondence principle for solving the crack problems of power law type nonlinear viscoelastic materials under the first type boundary condition is proposed.The solution of the crack-tip stress,strain fields for the power law type nonlinear viscoelastic materials,especially for the modified polypropylene, is obtained.展开更多
Based on the Gauss linear frequency modulated wavelet transform, a new characteristic index is presented, namely time frequency energy attenuation factor which can reflect the difference features of waveform in earthq...Based on the Gauss linear frequency modulated wavelet transform, a new characteristic index is presented, namely time frequency energy attenuation factor which can reflect the difference features of waveform in earthquake focus mechanism, wave traveling path and its attenuation characteristics in focal area or near field. In order to test its validity, we select the natural earthquakes and explosion or collapse events whose focus mechanisms vary obviously,and some natural earthquakes located at the same site or in a very small area. The study indicates that the time frequency energy attenuation factors of the natural earthquakes are obviously different with that of explosion or collapse events, and the change of the time frequency energy attenuation factors is relatively stable for the earthquakes under the normal seismicity background. Using the above mentioned method, it is expected to offer a useful criterion for strong earthquake prediction by continuous earthquake observation.展开更多
In this paper, we propose a new reduced-complexity decoding algorithm of Low-Density Parity-Check (LDPC) codes, called Belief-Propagation-Approximated (BPA) algorithm, which utilizes the idea of normalization and tran...In this paper, we propose a new reduced-complexity decoding algorithm of Low-Density Parity-Check (LDPC) codes, called Belief-Propagation-Approximated (BPA) algorithm, which utilizes the idea of normalization and translates approximately the intricate nonlinear operation in the check nodes of the original BP algorithm to only one operation of looking up the table. The normalization factors can be obtained by simulation, or theoretically. Simulation results demonstrate that BPA algorithm exhibits fairly satisfactory bit error performance on the Additive White Gaussian Noise (AWGN) channel.展开更多
Downlink transmit beamforming is a promising technique to reduce interference, and power control is a technique to adjust transmission power to satisfy the link quality. Joint transmission power control and beamformin...Downlink transmit beamforming is a promising technique to reduce interference, and power control is a technique to adjust transmission power to satisfy the link quality. Joint transmission power control and beamforming are proposed to minimize total transmission power. The joint optimization problem is solved by receiver beamforming and power control in virtual uplink. SIR based power control is performed to adjust the power allocation, and transmit beamforming weight vectors are determined by Minimum Variance Distortionless Response (MVDR) criterion. The multipath combining weight vectors are determined by maximum ratio combining criterion. Simulation results show the joint optimization scheme decreases the transmission power, and system performance is enhanced.展开更多
A perspective view for next generation mobile wireless network is given in this paper, named as Mobile Ubiquitous Service Environment (MUSE). The main mechanisms and principles for MUSE and related issues are also given.
With the development of electronics,dictionaries are changing their traditional images. The handy electronic dictionary is so convenient that it is popular among different kinds of dictionary users who rely on it more...With the development of electronics,dictionaries are changing their traditional images. The handy electronic dictionary is so convenient that it is popular among different kinds of dictionary users who rely on it more than on paper dictionaries. This paper intends to show evidence of the detrimental effects electronic dictionaries have left and suggest it is more advisable for students to trust a carefully-chosen paper dictionary for their vocabulary learning instead. Furthermore, the findings pose teachers with a serious issue to reconsider our teaching methods and to improve the way vocabulary is tested.展开更多
This article explores the ways and activities designed on the Whole Language Approach to foster learners' integrated language skills and their ability to understand and appreciate great English literary works. Bas...This article explores the ways and activities designed on the Whole Language Approach to foster learners' integrated language skills and their ability to understand and appreciate great English literary works. Based on the major principles of Whole Language instruction, the course syllabus requires that learners read and write on massive amount of English展开更多
The long symbol duration makes Orthogonal Frequency Division Multiplexing (OFDM) robust against frequency-selective fading, and also makes OFDM sensitive to time-selective fading. First, this paper deduces the Inter-s...The long symbol duration makes Orthogonal Frequency Division Multiplexing (OFDM) robust against frequency-selective fading, and also makes OFDM sensitive to time-selective fading. First, this paper deduces the Inter-subCarrier Interference (ICI) caused by time-selective fading, and then analyzes in detail how time-selective fading affects the performance of OFDM system, e.g. Bit-Error Rate (BER) and the channel capacity of each subcarrier. At last, some simulation figures are given.展开更多
The authors prove the global existence of weak solutions to 2-D incompressible Navier-Stokes equations (in vorticity-stream formulation) with initial votticity in L .It may be the best result that can be obtained for ...The authors prove the global existence of weak solutions to 2-D incompressible Navier-Stokes equations (in vorticity-stream formulation) with initial votticity in L .It may be the best result that can be obtained for initial vorticity in LP form. Moreover,the uniqueness is to be proved here.展开更多
文摘Several important factors affecting the efficiency of Agrobacterium-mediated rice transformation were studied with several predominant commercial indica and japonica rice cultivars. As far as indica rice callus was concerned, CC medium was the best and the quality of callus was improved with the addition of 1.0 to 2.0 mg/L ABA. It decreased the percentage of browning calli and improved the callus growing state by addition of a certain amount of sorbitol to the subculture medium. NB medium was the best for callus initiation of japonica rice, but the improvement in the quality of callus of japonica subspecies was not obvious by adding ABA. During the period of subculture, to a certain degree, increasing the sucrose concentration could improve the proportion of hygromycin resistant calli. Furthermore, the transformation efficiency would be higher by applying selection pressure in the selection stage, removing selection pressure during the plantlet differentiation period and applying selection pressure again during seedling hardening period. Besides, suitable combination of plant hormones was beneficial for callus differentiation. An efficient /Agrobacterium-mediated rice transformation system had been established for several rice cultivars and a lot of transgenic rice plants had been obtained.
文摘Effects of hypobaric storage on physiological and biochemical changes in Dong jujube fruit were investigated. Hypobaric storage significantly delayed the decrease in firmness and maintained content of ascorbic acid, reduced accumulation of ethanol and acetaldehyde in pulp and respiration, inhibited activities of ascorbic acid oxidase and alcohol dehydrogenase and slowed down the rate of ethylene production, but had little effect on flesh browning of the fruit.
基金Project supported by the Hunan Natural Science Foundation(Nos.01JJY3001 and 01JJY2001)Research Item of the Hunan Education Committee(No.01C083)and the Key Item of Hunan Science and Technology Department.
文摘The aim of this paper is to derive the power law type nonlinear viscoelastic crack-tip fields.For the requirement of later derivation,the HRR singular fields and the high-order asymp- totic fields are first examined.That they are essentially the isotropic,incompressible,power law type nonlinear elastic crack-tip fields is illustrated.After a concise review of the elasticity recov- ery correspondence principle for solving the nonlinear viscoelastic problems,the correspondence principle for solving the crack problems of power law type nonlinear viscoelastic materials under the first type boundary condition is proposed.The solution of the crack-tip stress,strain fields for the power law type nonlinear viscoelastic materials,especially for the modified polypropylene, is obtained.
文摘Based on the Gauss linear frequency modulated wavelet transform, a new characteristic index is presented, namely time frequency energy attenuation factor which can reflect the difference features of waveform in earthquake focus mechanism, wave traveling path and its attenuation characteristics in focal area or near field. In order to test its validity, we select the natural earthquakes and explosion or collapse events whose focus mechanisms vary obviously,and some natural earthquakes located at the same site or in a very small area. The study indicates that the time frequency energy attenuation factors of the natural earthquakes are obviously different with that of explosion or collapse events, and the change of the time frequency energy attenuation factors is relatively stable for the earthquakes under the normal seismicity background. Using the above mentioned method, it is expected to offer a useful criterion for strong earthquake prediction by continuous earthquake observation.
文摘In this paper, we propose a new reduced-complexity decoding algorithm of Low-Density Parity-Check (LDPC) codes, called Belief-Propagation-Approximated (BPA) algorithm, which utilizes the idea of normalization and translates approximately the intricate nonlinear operation in the check nodes of the original BP algorithm to only one operation of looking up the table. The normalization factors can be obtained by simulation, or theoretically. Simulation results demonstrate that BPA algorithm exhibits fairly satisfactory bit error performance on the Additive White Gaussian Noise (AWGN) channel.
基金This work is supported by Hi Tech Research and Development Program of China"863"(No.2004AA123180).
文摘Downlink transmit beamforming is a promising technique to reduce interference, and power control is a technique to adjust transmission power to satisfy the link quality. Joint transmission power control and beamforming are proposed to minimize total transmission power. The joint optimization problem is solved by receiver beamforming and power control in virtual uplink. SIR based power control is performed to adjust the power allocation, and transmit beamforming weight vectors are determined by Minimum Variance Distortionless Response (MVDR) criterion. The multipath combining weight vectors are determined by maximum ratio combining criterion. Simulation results show the joint optimization scheme decreases the transmission power, and system performance is enhanced.
文摘A perspective view for next generation mobile wireless network is given in this paper, named as Mobile Ubiquitous Service Environment (MUSE). The main mechanisms and principles for MUSE and related issues are also given.
文摘With the development of electronics,dictionaries are changing their traditional images. The handy electronic dictionary is so convenient that it is popular among different kinds of dictionary users who rely on it more than on paper dictionaries. This paper intends to show evidence of the detrimental effects electronic dictionaries have left and suggest it is more advisable for students to trust a carefully-chosen paper dictionary for their vocabulary learning instead. Furthermore, the findings pose teachers with a serious issue to reconsider our teaching methods and to improve the way vocabulary is tested.
文摘This article explores the ways and activities designed on the Whole Language Approach to foster learners' integrated language skills and their ability to understand and appreciate great English literary works. Based on the major principles of Whole Language instruction, the course syllabus requires that learners read and write on massive amount of English
文摘The long symbol duration makes Orthogonal Frequency Division Multiplexing (OFDM) robust against frequency-selective fading, and also makes OFDM sensitive to time-selective fading. First, this paper deduces the Inter-subCarrier Interference (ICI) caused by time-selective fading, and then analyzes in detail how time-selective fading affects the performance of OFDM system, e.g. Bit-Error Rate (BER) and the channel capacity of each subcarrier. At last, some simulation figures are given.
文摘The authors prove the global existence of weak solutions to 2-D incompressible Navier-Stokes equations (in vorticity-stream formulation) with initial votticity in L .It may be the best result that can be obtained for initial vorticity in LP form. Moreover,the uniqueness is to be proved here.
