Based on the statistical characteristics of energy spectrum and the features of spectrum-shifting in spectrometry,the parameter adjustment method of Gaussian function space was applied in the simulation of spectrum-sh...Based on the statistical characteristics of energy spectrum and the features of spectrum-shifting in spectrometry,the parameter adjustment method of Gaussian function space was applied in the simulation of spectrum-shifting.The transient characteristics of energy spectrum were described by the Gaussian function space,and then the Gaussian function space was transferred by parameter adjustment method.Furthermore,the spectrum-shifting in measurement of energy spectrum was simulated.The applied example shows that the parameters can be adjusted flexibly by this method to meet the various requirements in simulation of energy spectrum-shifting.This method was one parameterized simulation method with good performance for the practical application.展开更多
The restrictive, stereotyped behavior in autism spectrum disorder (ASD) is considered to be related to deficits in execu- tive function. In particular, cognitive shifting in executive function is deeply related to ste...The restrictive, stereotyped behavior in autism spectrum disorder (ASD) is considered to be related to deficits in execu- tive function. In particular, cognitive shifting in executive function is deeply related to stereotyped behavior in ASD. Previous investigations have clarified that the lateral prefrontal cortex is involved in cognitive shifting when flexible changes in attention were needed. However, a few studies have revealed a direct association between cognitive shifting tasks and lateral prefrontal cortex activity in children with ASD. We examined cognitive shifting in 7- to 12-year-old children with ASD and typically developing children using the dimensional change card sort task. In addition, using near-infrared spectroscopy, we examined prefrontal brain activity in conjunction with cognitive shifting. The autistic children provided fewer correct answers and slower reaction times in the task than typically developing children. Fur- thermore, the autistic children displayed a decline in right lateral prefrontal cortex activity during the task compared with typically developing children. In addition, a negative correlation was observed between the severity of autism and brain activity during the task. These results suggest that the activity and physiological indices used in this study may be useful for identifying the symptoms of ASD and discriminating ASD from other disabilities.展开更多
Traditional ligand-field theory has to be improved by taking into account both pure electronic contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy).By means of improved li...Traditional ligand-field theory has to be improved by taking into account both pure electronic contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy).By means of improved ligand-field theory,the R line,t_2^(32)T_1 and t_2^(32)T_2 lines,t_2~2(~3T_1)e^4T_2,t_2~2(~3T_1)e^4T_1 and t_2e^2(~4A_2)~4T_1 bands,g factors of t_2~3 ~4A_2 and t_2^(32)E,four strain-induced level-splittings and R-line thermal shift of MgO:V^(2+) have been calculated.The results are in very good agreement with the experimental data.It is found that for MgO:V^(2+),the contributions due to electron- phonon interaction (EPI) come from the first-order term;the contributions from the second-order and higher terms are insignificant.In thermal shift of R line of MgO:V^(2+),the temperature-dependent contribution due to EPI is dominant. The results obtained in this work may be used in theoretical calculations of other effects of EPI.展开更多
The high-resolution absorption spectra of the (2,0),(3,1),and (8,5) bands of the A^2Π^u-X^2∑g^+ system of ^15N2^+ have been recorded by using velocity modulation spectroscopy technique in the near infrared r...The high-resolution absorption spectra of the (2,0),(3,1),and (8,5) bands of the A^2Π^u-X^2∑g^+ system of ^15N2^+ have been recorded by using velocity modulation spectroscopy technique in the near infrared region.The rotational constants of the X^2∑g^+ and A^2Πu states of ^15N2^+ were derived from the spectroscopic data.The isotope shifts of these bands of the A^2Πu-X^2∑g^+ system of ^14N2^+ and ^15N2^+ were also analyzed and discussed.展开更多
Based on the rotation transformation in phase space and the technique of integration within an ordered product of operators, the coherent state representation of the multimode phase shifting operator and one of its ne...Based on the rotation transformation in phase space and the technique of integration within an ordered product of operators, the coherent state representation of the multimode phase shifting operator and one of its new applications in quantum mechanics are given. It is proved that the coherent state is a natural language for describing the phase shifting operator or multimode phase shifting operator. The multimode phase shifting operator is also a useful tool to solve the dynamic problems of the mnltimode coordinate-momentum coupled harmonic oscillators. The exact energy spectra and eigenstates of such multimode coupled harmonic oscillators can be easily obtained by using the rnultimode phase shifting operator.展开更多
A complete answer to the shiftability of a principal shift invariant spaces and a scaled version is given. The congruence of spectrum plays a kernel role. It characterizes essentially the shiftability and the scale ...A complete answer to the shiftability of a principal shift invariant spaces and a scaled version is given. The congruence of spectrum plays a kernel role. It characterizes essentially the shiftability and the scale of any principal shift variant spaces. Some examples relative to signal analysis are discussed associated with an explanation to the failure of generalizing Shannon s sampling theorem from band limitted to band pass case.展开更多
The paper presents a kind of transmission system which employs M-ary Position Phase Shift Keying(MPPSK) to send data and Phase Locked Loop(PLL) based techniques for data retrieve.With a single PLL, MPPSK demodulation ...The paper presents a kind of transmission system which employs M-ary Position Phase Shift Keying(MPPSK) to send data and Phase Locked Loop(PLL) based techniques for data retrieve.With a single PLL, MPPSK demodulation is achieved, as well as carrier recovery and symbol synchronization.Firstly, MPPSK modulation method is briefly introduced.2PPSK's PSD expression is given with its optimization result.Orthogonal Phase Detector(PD) and static threshold are used for the purpose of wider phase range and simplicity in demodulation.The data rate is alterable, which is 4.65 kbps for 2PPSK and 9.3 kbps for 4PPSK in the paper.Then some indicative comparisons in Signal to Noise Ratio Symbol Error Rate(SNR-SER) are made among 2PPSK, 3PPSK and 4PPSK, of which 4PPSK has proved to be optimal in ten slots each symbol conditions.And finally, it is demonstrated by system simulations that lower than 10-4 Symbol Error Rate(SER) performance can be obtained at 13 dB symbol SNR.展开更多
根据频谱扩展-压缩(spectrum spread and compression,SSC)移频干扰信号和回波信号时频分布特性的差异,提出一种基于广义S变换和Tsallis交叉熵阈值分割的干扰抑制方法。分析了SSC移频干扰的干扰原理和干扰信号经过解线调后的信号形式,...根据频谱扩展-压缩(spectrum spread and compression,SSC)移频干扰信号和回波信号时频分布特性的差异,提出一种基于广义S变换和Tsallis交叉熵阈值分割的干扰抑制方法。分析了SSC移频干扰的干扰原理和干扰信号经过解线调后的信号形式,并利用时频聚焦性较好的广义S变换获取接收信号经过解线调后的时频图像,根据时频图像对应的灰度图像,以Tsallis交叉熵最小化作为目标函数,求出灰度图像的最佳分割阈值,并根据分割阈值构建时频滤波器,实现干扰抑制。仿真结果表明:该方法对于SSC移频干扰产生的假目标具有较好的抑制效果,干扰抑制比可达30 dB以上。展开更多
Frequency Hopping Spread Spectrum (FHSS) system is often deployed to protect wireless communication from jamming or to preclude undesired reception of the signal. Such themes can only be achieved if the jammer or unde...Frequency Hopping Spread Spectrum (FHSS) system is often deployed to protect wireless communication from jamming or to preclude undesired reception of the signal. Such themes can only be achieved if the jammer or undesired receiver does not have the knowledge of the spreading code. For this reason, unencrypted M-sequences are a deficient choice for the spreading code when a high level of security is required. The primary objective of this paper is to analyze vulnerability of linear feedback shift register (LFSRs) codes. Then, a new method based on encryption algorithm applied over spreading codes, named hidden frequency hopping is proposed to improve the security of FHSS. The proposed encryption security algorithm is highly reliable, and can be applied to all existing data communication systems based on spread spectrum techniques. Since the multi-user detection is an inherent characteristic for FHSS, the multi-user interference must be studied carefully. Hence, a new method called optimum pair “key-input” selection is proposed which reduces interference below the desired constant threshold.展开更多
基金Supported by National Natural Science Foundation of China(41204133)Scientific Reserch Fund of Sichuan Provincial Education Department(13ZA0066)Cultivating programme of excellent innovation team of Chengdu University of technology(KYTD201301)
文摘Based on the statistical characteristics of energy spectrum and the features of spectrum-shifting in spectrometry,the parameter adjustment method of Gaussian function space was applied in the simulation of spectrum-shifting.The transient characteristics of energy spectrum were described by the Gaussian function space,and then the Gaussian function space was transferred by parameter adjustment method.Furthermore,the spectrum-shifting in measurement of energy spectrum was simulated.The applied example shows that the parameters can be adjusted flexibly by this method to meet the various requirements in simulation of energy spectrum-shifting.This method was one parameterized simulation method with good performance for the practical application.
文摘The restrictive, stereotyped behavior in autism spectrum disorder (ASD) is considered to be related to deficits in execu- tive function. In particular, cognitive shifting in executive function is deeply related to stereotyped behavior in ASD. Previous investigations have clarified that the lateral prefrontal cortex is involved in cognitive shifting when flexible changes in attention were needed. However, a few studies have revealed a direct association between cognitive shifting tasks and lateral prefrontal cortex activity in children with ASD. We examined cognitive shifting in 7- to 12-year-old children with ASD and typically developing children using the dimensional change card sort task. In addition, using near-infrared spectroscopy, we examined prefrontal brain activity in conjunction with cognitive shifting. The autistic children provided fewer correct answers and slower reaction times in the task than typically developing children. Fur- thermore, the autistic children displayed a decline in right lateral prefrontal cortex activity during the task compared with typically developing children. In addition, a negative correlation was observed between the severity of autism and brain activity during the task. These results suggest that the activity and physiological indices used in this study may be useful for identifying the symptoms of ASD and discriminating ASD from other disabilities.
文摘Traditional ligand-field theory has to be improved by taking into account both pure electronic contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy).By means of improved ligand-field theory,the R line,t_2^(32)T_1 and t_2^(32)T_2 lines,t_2~2(~3T_1)e^4T_2,t_2~2(~3T_1)e^4T_1 and t_2e^2(~4A_2)~4T_1 bands,g factors of t_2~3 ~4A_2 and t_2^(32)E,four strain-induced level-splittings and R-line thermal shift of MgO:V^(2+) have been calculated.The results are in very good agreement with the experimental data.It is found that for MgO:V^(2+),the contributions due to electron- phonon interaction (EPI) come from the first-order term;the contributions from the second-order and higher terms are insignificant.In thermal shift of R line of MgO:V^(2+),the temperature-dependent contribution due to EPI is dominant. The results obtained in this work may be used in theoretical calculations of other effects of EPI.
基金supported by the National Natural Science Foundation of China(Grant No.11674096)
文摘The high-resolution absorption spectra of the (2,0),(3,1),and (8,5) bands of the A^2Π^u-X^2∑g^+ system of ^15N2^+ have been recorded by using velocity modulation spectroscopy technique in the near infrared region.The rotational constants of the X^2∑g^+ and A^2Πu states of ^15N2^+ were derived from the spectroscopic data.The isotope shifts of these bands of the A^2Πu-X^2∑g^+ system of ^14N2^+ and ^15N2^+ were also analyzed and discussed.
基金Project supported by the Natural Science Foundation of Shandong Province of China (Grant No. Y2008A16)the Natural Science Foundation of Heze University of Shandong Province, China (Grant No. XY09WL01)
文摘Based on the rotation transformation in phase space and the technique of integration within an ordered product of operators, the coherent state representation of the multimode phase shifting operator and one of its new applications in quantum mechanics are given. It is proved that the coherent state is a natural language for describing the phase shifting operator or multimode phase shifting operator. The multimode phase shifting operator is also a useful tool to solve the dynamic problems of the mnltimode coordinate-momentum coupled harmonic oscillators. The exact energy spectra and eigenstates of such multimode coupled harmonic oscillators can be easily obtained by using the rnultimode phase shifting operator.
文摘A complete answer to the shiftability of a principal shift invariant spaces and a scaled version is given. The congruence of spectrum plays a kernel role. It characterizes essentially the shiftability and the scale of any principal shift variant spaces. Some examples relative to signal analysis are discussed associated with an explanation to the failure of generalizing Shannon s sampling theorem from band limitted to band pass case.
基金Supported by National Natural Science Foundation of China (60472054)
文摘The paper presents a kind of transmission system which employs M-ary Position Phase Shift Keying(MPPSK) to send data and Phase Locked Loop(PLL) based techniques for data retrieve.With a single PLL, MPPSK demodulation is achieved, as well as carrier recovery and symbol synchronization.Firstly, MPPSK modulation method is briefly introduced.2PPSK's PSD expression is given with its optimization result.Orthogonal Phase Detector(PD) and static threshold are used for the purpose of wider phase range and simplicity in demodulation.The data rate is alterable, which is 4.65 kbps for 2PPSK and 9.3 kbps for 4PPSK in the paper.Then some indicative comparisons in Signal to Noise Ratio Symbol Error Rate(SNR-SER) are made among 2PPSK, 3PPSK and 4PPSK, of which 4PPSK has proved to be optimal in ten slots each symbol conditions.And finally, it is demonstrated by system simulations that lower than 10-4 Symbol Error Rate(SER) performance can be obtained at 13 dB symbol SNR.
文摘根据频谱扩展-压缩(spectrum spread and compression,SSC)移频干扰信号和回波信号时频分布特性的差异,提出一种基于广义S变换和Tsallis交叉熵阈值分割的干扰抑制方法。分析了SSC移频干扰的干扰原理和干扰信号经过解线调后的信号形式,并利用时频聚焦性较好的广义S变换获取接收信号经过解线调后的时频图像,根据时频图像对应的灰度图像,以Tsallis交叉熵最小化作为目标函数,求出灰度图像的最佳分割阈值,并根据分割阈值构建时频滤波器,实现干扰抑制。仿真结果表明:该方法对于SSC移频干扰产生的假目标具有较好的抑制效果,干扰抑制比可达30 dB以上。
文摘Frequency Hopping Spread Spectrum (FHSS) system is often deployed to protect wireless communication from jamming or to preclude undesired reception of the signal. Such themes can only be achieved if the jammer or undesired receiver does not have the knowledge of the spreading code. For this reason, unencrypted M-sequences are a deficient choice for the spreading code when a high level of security is required. The primary objective of this paper is to analyze vulnerability of linear feedback shift register (LFSRs) codes. Then, a new method based on encryption algorithm applied over spreading codes, named hidden frequency hopping is proposed to improve the security of FHSS. The proposed encryption security algorithm is highly reliable, and can be applied to all existing data communication systems based on spread spectrum techniques. Since the multi-user detection is an inherent characteristic for FHSS, the multi-user interference must be studied carefully. Hence, a new method called optimum pair “key-input” selection is proposed which reduces interference below the desired constant threshold.