The spatially-resolved laser-based high-resolution angle resolved photoemission spectroscopy(ARPES) measurements have been performed on the optimally-doped YBa_(2)Cu_(3)O_(7)-σ(Y123) superconductor. For the first tim...The spatially-resolved laser-based high-resolution angle resolved photoemission spectroscopy(ARPES) measurements have been performed on the optimally-doped YBa_(2)Cu_(3)O_(7)-σ(Y123) superconductor. For the first time, we found the region from the cleaved surface that reveals clear bulk electronic properties. The intrinsic Fermi surface and band structures of Y123 were observed. The Fermi surface-dependent and momentum-dependent superconducting gap was determined which is nodeless and consistent with the d+is gap form.展开更多
提出了一种分析多层印刷电路板电源分配网络(power distribution network,PDN)中一维(1D)介质型电磁带隙(electromagnetic band-gap,EBG)结构噪声隔离性能的1D有限元数值计算方法.将1D介质型EBG的3D结构简化为1D有限元模型,通过直接求...提出了一种分析多层印刷电路板电源分配网络(power distribution network,PDN)中一维(1D)介质型电磁带隙(electromagnetic band-gap,EBG)结构噪声隔离性能的1D有限元数值计算方法.将1D介质型EBG的3D结构简化为1D有限元模型,通过直接求解波动方程获得传输系数T、反射系数R以及散射参数S.利用R-T曲线可直观地判定频率禁带,而采用分贝表示的S21参数则更方便评价噪声隔离度.根据介质型EBG的周期数、介电常数和周期长度等参数对噪声隔离性能影响的仿真结果,针对少周期、不完全禁带EBG结构提出了先采用多周期EBG结构预测禁带,再通过调整介电常数和周期长度扩展禁带和增强噪声隔离度的两阶段设计方法.采用3D全波电磁仿真验证了1D有限元算法的合理性.展开更多
Six circularly polarized patch antennas with electromagnetic band gap(EBG)arranged at different locations were studied.These EBG antennas were compared in terms of impedance bandwidth,axial ratio(AR)bandwidth and radi...Six circularly polarized patch antennas with electromagnetic band gap(EBG)arranged at different locations were studied.These EBG antennas were compared in terms of impedance bandwidth,axial ratio(AR)bandwidth and radiation patterns.When the EBG cells were placed closer to the edge of the substrate,the EBG antenna had a larger front radiation and a narrower bandwidth.Integrating the EBG cells closer to the center of the patch resulted in a wider impedance bandwidth,a wider axial ratio bandwidth and a decreased front gain.展开更多
An approach is proposed to estimate the transfer function of the periodic structure, which is known as an absorber due to its repetitive cells leading to the band gap phenomenon. The band gap is a frequency range in w...An approach is proposed to estimate the transfer function of the periodic structure, which is known as an absorber due to its repetitive cells leading to the band gap phenomenon. The band gap is a frequency range in which vibration will be inhibited. A transfer function is usually performed to gain band gap. Previous scholars regard estimation of the transfer function as a forward problem assuming known cell mass and stiffness matrices. However, the estimation of band gap for irregular or complicated cells is hardly accurate because it is difficult to model the cell exactly. Therefore, we treat the estimation as an inverse problem by employing modal identification and curve fitting. A transfer matrix is then established by parameters identitled through modal analysis. Both simulations and experiments have been performed. Some interesting conclusions about the relationship between modal parameters and band gap have been achieved.展开更多
Anovel compact E shape High Impedance Surface(HIS) Electromagnetic Band-Gap(EBG) comprising Amended Minkowski Fractal Boundary(AMFB),Added Metal Strips(AMS),and metal plated via printed on a Rogers TMM 10i substrate i...Anovel compact E shape High Impedance Surface(HIS) Electromagnetic Band-Gap(EBG) comprising Amended Minkowski Fractal Boundary(AMFB),Added Metal Strips(AMS),and metal plated via printed on a Rogers TMM 10i substrate is presented.The first order AMFB and ABS are introduced for equivalent capacitance enhancement and miniaturization with effective space-filling characteristics.The dimension of lattice size is only The proposed structure exhibits a most compact characteristic about 35% size reduction as compared with conven-tional mushroom-like HIS-EBG,and better surface-wave decoupling of around 9 dB at the operating frequency band.Details of design parameters which affect the whole performance of certain band-gap are intensively investigated.A constructed prototype is potential candidate for antenna system per-formance enhancement.展开更多
This paper presents a three-dimensional particle-in-cell (PIC) simulation of a Ka-band relativistic Cherenkov source with a slow wave structure (SWS) consisting of metal photonic band gap (PBG) structures. In the simu...This paper presents a three-dimensional particle-in-cell (PIC) simulation of a Ka-band relativistic Cherenkov source with a slow wave structure (SWS) consisting of metal photonic band gap (PBG) structures. In the simulation, a perfect match layer boundary is employed to absorb passing band modes supported by the PBG lattice with an artificial metal boundary. The simulated axial field distributions in the cross section and surface of the SWS demonstrate that the device operates in the vicinity of the π point of a TM01-like mode. The Fourier transformation spectra of the axial fields as functions of time and space show that only a single frequency appears at 36.27 GHz, which is in good agreement with that of the intersection of the dispersion curve with the slow space charge wave generated on the beam. The simulation results demonstrate that the SWS has good mode selectivity.展开更多
Two new quaternary sulfides,KSmSiS4(1) and KYbSiS4(2),have been synthesized by high-temperature solid-state reaction.Single-crystal X-ray diffraction analyses indicate that both compounds crystallize in the space grou...Two new quaternary sulfides,KSmSiS4(1) and KYbSiS4(2),have been synthesized by high-temperature solid-state reaction.Single-crystal X-ray diffraction analyses indicate that both compounds crystallize in the space group P21/m,and the crystal data are as follows:a = 6.426(11),b = 6.582(11),c = 8.602(15) ,β = 107.90(13)°,Z = 2,V = 346.2(10) 3,Dc = 3.317 g/cm3,F(000) = 318,μ(MoKα) = 10.334 mm-1,the final R = 0.0559 and wR = 0.1370 for 1;and a = 6.3244(10),b = 6.5552(10),c = 8.5701(15) ,β = 108.001(13)°,Z = 2,V = 337.91(9) 3,Dc = 3.621 g/cm3,F(000) = 334,μ(MoKα) = 15.737 mm-1,the final R = 0.0422 and wR = 0.0960 for 2.The KLnSiS4(Ln = Sm,Yb) structure consists of corrugated ∞2 [LnSiS4]-layers which are formed by edge-sharing LnS8 bicapped trigonal prisms and SiS4 tetrahedra.The K+ cations are located in the cavities defined by S2-anions between the ∞2 [LnSiS4]-layers.Band-gap analyses show that compounds 1 and 2 are semiconductors with optical band-gaps of 2.40 and 2.34 eV,respectively.展开更多
Wavelets is a very effective technique for time-frequency analysis with the ability of preserving loeal information, applied to many areas such as nonlinear science, information processing.quantum physics etc.. In thi...Wavelets is a very effective technique for time-frequency analysis with the ability of preserving loeal information, applied to many areas such as nonlinear science, information processing.quantum physics etc.. In this paper. from the view of ecology spatial pattern, the authors try to process the sample data of Larix forest transects to identify the canopy gap structures by wavelet analysis. The caleulation of wavelet variance, derived from the transtform facilitates comparison based on dominant scale of pattern between multiple datasets such as the stands described.展开更多
Two-dimensional function photonic crystals, in which the dielectric constants of medium columns are the functions of space coordinates , are proposed and studied numerically. The band gaps structures of the photonic c...Two-dimensional function photonic crystals, in which the dielectric constants of medium columns are the functions of space coordinates , are proposed and studied numerically. The band gaps structures of the photonic crystals for TE and TM waves are different from the two-dimensional conventional photonic crystals. Some absolute band gaps and semiDirac points are found. When the medium column radius and the function form of the dielectric constant are modulated, the numbers, width, and position of band gaps are changed, and the semi-Dirac point can either occur or disappear. Therefore,the special band gaps structures and semi-Dirac points can be achieved through the modulation on the two-dimensional function photonic crystals. The results will provide a new design method of optical devices based on the two-dimensional function photonic crystals.展开更多
Previous calculations show that the two-dimensional(2 D) silicon carbide(SiC) honeycomb structure is a structurally stable monolayer. Following this, we investigate the electronic properties of the hydrogen and fluori...Previous calculations show that the two-dimensional(2 D) silicon carbide(SiC) honeycomb structure is a structurally stable monolayer. Following this, we investigate the electronic properties of the hydrogen and fluorine functionalized SiC monolayer by first-principles calculations. Our results show that the functionalized monolayer becomes metallic after semi-hydrogenation or semi-fluorination, while the semiconducting properties are obtained by the full functionalization. Compared with the bare SiC monolayer, the band gap of the fully hydrogenated system is increased, in comparison with the decrease of the gap in the fully fluorinated case. As a result, the band gap can be tuned from 0.73 to 4.14 eV by the functionalization. In addition to the metal-semiconductor transition, hydrogenation and functionalization also realize a direct-indirect semiconducting transition in the 2 D SiC monolayer. These results provide theoretical guidance for design of photoelectric devices based on the SiC monolayer.展开更多
On January 21, 2016, a strong earthquake with a magnitude of Ms6.4 occurred at Menyuan,Qinghai Province of China. In almost the same region, there was another strong earthquake happened in 1986, with similar magnitude...On January 21, 2016, a strong earthquake with a magnitude of Ms6.4 occurred at Menyuan,Qinghai Province of China. In almost the same region, there was another strong earthquake happened in 1986, with similar magnitude and focal mechanism. Based on comprehensive analysis of regional active faults, focal mechanism solutions, precise locations of aftershocks, as well as GPS crustal deformation, we inferred that the Lenglongling active fault dips NE rather than SW as suggested by previous studies. Considering the facts that the 2016 and 1986 Ms6.4 Menyuan earthquakes are closely located with similar focal mechanisms, both of the quakes are on the north side of the Lenglongling Fault and adjacent to the fault, and the fault is dipping NE direction, we suggest that the fault should be the seismogenic structure of the two events. The Lenglongling Fault, as the western segment of the well-known Tianzhu seismic gap in the Qilian-Haiyuan active fault system,is in a relatively active state with frequent earthquakes in recent years, implying a high level of strain accumulation and a high potential of major event. It is also possible that the Lenglongling Fault and its adjacent fault, the Jinqianghe Fault in the Tianzhu seismic gap,are rupturing simultaneously in the future.展开更多
This paper studies the dispersion characteristics of a modified photonic band-gap slow-wave structure with an open boundary by simulation and experiment.A mode launcher with a wheel radiator and a coupling probe is pr...This paper studies the dispersion characteristics of a modified photonic band-gap slow-wave structure with an open boundary by simulation and experiment.A mode launcher with a wheel radiator and a coupling probe is presented to excite a pure TM 01-like mode.The cold test and simulation results show that the TM 01-like mode is effectively excited and no parasitic modes appear.The dispersion characteristics obtained from the cold test are in good agreement with the calculated results.展开更多
Two kinds of compact electromagnetic band gap (EBG) structures are designed.A two layer compact EBG structure configured with cross spiral shape line inductors and interdigital capacitors is first presented.Because of...Two kinds of compact electromagnetic band gap (EBG) structures are designed.A two layer compact EBG structure configured with cross spiral shape line inductors and interdigital capacitors is first presented.Because of its significantly enlarged equivalent inductor and capacitance,the period of the lattice is approximately 4.5% of the free space wavelength.By insetting several narrow slits in the ground plane,the bandwidth of the main bandgap is enhanced by nearly 19%.Further effort has been made for designing a three layer compact EBG structure.Simulation results show that its period is reduced by about 26% compared to that of proposed two layer EBG structure,and the bandwidth of the main bandgap is about 3 times as that of the proposed two layer EBG structure.The detailed designs including a two layer compact 3×7 EBG array with and without defect ground plane and the three layer EBG array are given and simulation results are presented.展开更多
The antioxidant and gap junctional communication(GJC) activities of carotenoids are known to be the two main anticancer mechanisms.Quantitative structure-activity relationship(QSAR) models of the two activities were d...The antioxidant and gap junctional communication(GJC) activities of carotenoids are known to be the two main anticancer mechanisms.Quantitative structure-activity relationship(QSAR) models of the two activities were developed using stepwise regression and multilayer perceptron neural network based on the calculated descriptors of quantum chemistry.The results showed that the significant molecular descriptor related to the antioxidant activity of carotenoids was the HOMO-LUMO energy gap(EHL) and the molecular descriptor related to the GJC was the lowest unoccupied molecular orbital energy(ELUMO).The two models of antioxidant activity both showed good predictive power,but the predictive power of the neural network QSAR model of antioxidant activity was better.In addition,the two GJC models have similar,moderate predictive power.The possible mechanisms of antioxidant activity and GJC of carotenoids were discussed.展开更多
The transmission properties of compound frequency selective structures with dielectric slab and air gaps were investigated by computation and experimentation.Mechanism analyses were also carried out.Results show that ...The transmission properties of compound frequency selective structures with dielectric slab and air gaps were investigated by computation and experimentation.Mechanism analyses were also carried out.Results show that the air gaps have a distinct influence on the transmission properties.Resonant frequency of the structure would increase rapidly when the air gap appears.After the gap gets larger to a specific value,generally 1/5 wavelength corresponding to the resonant frequency,the transmission properties would change periodically with the gap thickness.The change of transmission properties in one period has a close relationship with the dielectric thickness.These results provide a new method for designing a bandpass radome of large incidence angle and low loss with the concept of stealth shield radome.展开更多
Firstly,this paper conducts theoretical analysis and current situation analysis,and then proposes research hypotheses.Secondly,using spatial Dubin model and partial differential method,it empirically studies the impac...Firstly,this paper conducts theoretical analysis and current situation analysis,and then proposes research hypotheses.Secondly,using spatial Dubin model and partial differential method,it empirically studies the impact of industrial structure advancement and rationalization on the urban-rural income gap.The results show that:(1)Both industrial structure and urban-rural income gap have significant spatial dependence;(2)The increase in the industrial structure rationalization will narrow the urban-rural income gap in local region,while its spillover effect on neighboring areas is not obvious.(3)The impact of the industrial structure advancement on the urban-rural income gap is not linear.It is first expanded and then narrowed.The industrial structure advancement in the Yangtze River Delta will generally narrow the urban-rural income gap at this stage.Finally,this paper put forward relevant suggestions.展开更多
We carry out detailed momentum-dependent and temperature-dependent measurements on Bi_2Sr_2CaCu_2O_(8+δ)(Bi2212) superconductor in the superconducting and pseudogap states by super-high resolution laser-based anglere...We carry out detailed momentum-dependent and temperature-dependent measurements on Bi_2Sr_2CaCu_2O_(8+δ)(Bi2212) superconductor in the superconducting and pseudogap states by super-high resolution laser-based angleresolved photoemission spectroscopy. The precise determination of the superconducting gap for the nearly optimally doped Bi2212(T_c= 91 K) at low temperature indicates that the momentum-dependence of the superconducting gap deviates from the standard d-wave form(cos(2Φ)). It can be alternatively fitted by including a high-order term(cos(6Φ)) in which the next nearest-neighbor interaction is considered. We find that the band structure near the antinodal region smoothly evolves across the pseudogap temperature without a signature of band reorganization which is distinct from that found in Bi_2Sr_2CuO_(6+δ) superconductors. This indicates that the band reorganization across the pseudogap temperature is not a universal behavior in cuprate superconductors.These results provide new insights in understanding the nature of the superconducting gap and pseudogap in high-temperature cuprate superconductors.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11888101 and 11974404)the National Key Research and Development Program of China (Grant Nos. 2021YFA1401800 and 2018YFA0704200)+3 种基金the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant Nos. XDB25000000 and XDB33000000)the Youth Innovation Promotion Association of CAS (Grant No. Y2021006)Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0301800)the Synergetic Extreme Condition User Facility (SECUF)。
文摘The spatially-resolved laser-based high-resolution angle resolved photoemission spectroscopy(ARPES) measurements have been performed on the optimally-doped YBa_(2)Cu_(3)O_(7)-σ(Y123) superconductor. For the first time, we found the region from the cleaved surface that reveals clear bulk electronic properties. The intrinsic Fermi surface and band structures of Y123 were observed. The Fermi surface-dependent and momentum-dependent superconducting gap was determined which is nodeless and consistent with the d+is gap form.
文摘提出了一种分析多层印刷电路板电源分配网络(power distribution network,PDN)中一维(1D)介质型电磁带隙(electromagnetic band-gap,EBG)结构噪声隔离性能的1D有限元数值计算方法.将1D介质型EBG的3D结构简化为1D有限元模型,通过直接求解波动方程获得传输系数T、反射系数R以及散射参数S.利用R-T曲线可直观地判定频率禁带,而采用分贝表示的S21参数则更方便评价噪声隔离度.根据介质型EBG的周期数、介电常数和周期长度等参数对噪声隔离性能影响的仿真结果,针对少周期、不完全禁带EBG结构提出了先采用多周期EBG结构预测禁带,再通过调整介电常数和周期长度扩展禁带和增强噪声隔离度的两阶段设计方法.采用3D全波电磁仿真验证了1D有限元算法的合理性.
基金Supported by the National Natural Science Foundation of China(61102022)the Fundamental Research Foundation of Beijing Institute of Technology of China(20120542014)
文摘Six circularly polarized patch antennas with electromagnetic band gap(EBG)arranged at different locations were studied.These EBG antennas were compared in terms of impedance bandwidth,axial ratio(AR)bandwidth and radiation patterns.When the EBG cells were placed closer to the edge of the substrate,the EBG antenna had a larger front radiation and a narrower bandwidth.Integrating the EBG cells closer to the center of the patch resulted in a wider impedance bandwidth,a wider axial ratio bandwidth and a decreased front gain.
基金the National Natural Science Foundation of China(Grant No.11272235).
文摘An approach is proposed to estimate the transfer function of the periodic structure, which is known as an absorber due to its repetitive cells leading to the band gap phenomenon. The band gap is a frequency range in which vibration will be inhibited. A transfer function is usually performed to gain band gap. Previous scholars regard estimation of the transfer function as a forward problem assuming known cell mass and stiffness matrices. However, the estimation of band gap for irregular or complicated cells is hardly accurate because it is difficult to model the cell exactly. Therefore, we treat the estimation as an inverse problem by employing modal identification and curve fitting. A transfer matrix is then established by parameters identitled through modal analysis. Both simulations and experiments have been performed. Some interesting conclusions about the relationship between modal parameters and band gap have been achieved.
基金Supported by the 2010 Natural Science Foundation of Shanghai (No. 09ZR1430400)
文摘Anovel compact E shape High Impedance Surface(HIS) Electromagnetic Band-Gap(EBG) comprising Amended Minkowski Fractal Boundary(AMFB),Added Metal Strips(AMS),and metal plated via printed on a Rogers TMM 10i substrate is presented.The first order AMFB and ABS are introduced for equivalent capacitance enhancement and miniaturization with effective space-filling characteristics.The dimension of lattice size is only The proposed structure exhibits a most compact characteristic about 35% size reduction as compared with conven-tional mushroom-like HIS-EBG,and better surface-wave decoupling of around 9 dB at the operating frequency band.Details of design parameters which affect the whole performance of certain band-gap are intensively investigated.A constructed prototype is potential candidate for antenna system per-formance enhancement.
基金Project supported by the National Key Basic Research Program of China (Grant No 2007CB31040)the National Natural Science Foundation of China (Grant No 60571020)
文摘This paper presents a three-dimensional particle-in-cell (PIC) simulation of a Ka-band relativistic Cherenkov source with a slow wave structure (SWS) consisting of metal photonic band gap (PBG) structures. In the simulation, a perfect match layer boundary is employed to absorb passing band modes supported by the PBG lattice with an artificial metal boundary. The simulated axial field distributions in the cross section and surface of the SWS demonstrate that the device operates in the vicinity of the π point of a TM01-like mode. The Fourier transformation spectra of the axial fields as functions of time and space show that only a single frequency appears at 36.27 GHz, which is in good agreement with that of the intersection of the dispersion curve with the slow space charge wave generated on the beam. The simulation results demonstrate that the SWS has good mode selectivity.
基金supported by the NNSFC (20521101)NSF for Distinguished Young Scientist of China (20425104)+1 种基金NSF of Fujian Province (2007J0173)the Fund of Fujian Key Laboratory of Nanomaterials (2006L2005)
文摘Two new quaternary sulfides,KSmSiS4(1) and KYbSiS4(2),have been synthesized by high-temperature solid-state reaction.Single-crystal X-ray diffraction analyses indicate that both compounds crystallize in the space group P21/m,and the crystal data are as follows:a = 6.426(11),b = 6.582(11),c = 8.602(15) ,β = 107.90(13)°,Z = 2,V = 346.2(10) 3,Dc = 3.317 g/cm3,F(000) = 318,μ(MoKα) = 10.334 mm-1,the final R = 0.0559 and wR = 0.1370 for 1;and a = 6.3244(10),b = 6.5552(10),c = 8.5701(15) ,β = 108.001(13)°,Z = 2,V = 337.91(9) 3,Dc = 3.621 g/cm3,F(000) = 334,μ(MoKα) = 15.737 mm-1,the final R = 0.0422 and wR = 0.0960 for 2.The KLnSiS4(Ln = Sm,Yb) structure consists of corrugated ∞2 [LnSiS4]-layers which are formed by edge-sharing LnS8 bicapped trigonal prisms and SiS4 tetrahedra.The K+ cations are located in the cavities defined by S2-anions between the ∞2 [LnSiS4]-layers.Band-gap analyses show that compounds 1 and 2 are semiconductors with optical band-gaps of 2.40 and 2.34 eV,respectively.
文摘Wavelets is a very effective technique for time-frequency analysis with the ability of preserving loeal information, applied to many areas such as nonlinear science, information processing.quantum physics etc.. In this paper. from the view of ecology spatial pattern, the authors try to process the sample data of Larix forest transects to identify the canopy gap structures by wavelet analysis. The caleulation of wavelet variance, derived from the transtform facilitates comparison based on dominant scale of pattern between multiple datasets such as the stands described.
基金Project supported by the National Natural Science Foundations of China(Grant No.61275047)the Research Project of Chinese Ministry of Education(Grant No.213009A)the Scientific and Technological Development Foundation of Jilin Province,China(Grant No.20130101031JC)
文摘Two-dimensional function photonic crystals, in which the dielectric constants of medium columns are the functions of space coordinates , are proposed and studied numerically. The band gaps structures of the photonic crystals for TE and TM waves are different from the two-dimensional conventional photonic crystals. Some absolute band gaps and semiDirac points are found. When the medium column radius and the function form of the dielectric constant are modulated, the numbers, width, and position of band gaps are changed, and the semi-Dirac point can either occur or disappear. Therefore,the special band gaps structures and semi-Dirac points can be achieved through the modulation on the two-dimensional function photonic crystals. The results will provide a new design method of optical devices based on the two-dimensional function photonic crystals.
基金Supported by the Program for New Century Excellent Talents in Universities of China under Grant No NCET-09-0867
文摘Previous calculations show that the two-dimensional(2 D) silicon carbide(SiC) honeycomb structure is a structurally stable monolayer. Following this, we investigate the electronic properties of the hydrogen and fluorine functionalized SiC monolayer by first-principles calculations. Our results show that the functionalized monolayer becomes metallic after semi-hydrogenation or semi-fluorination, while the semiconducting properties are obtained by the full functionalization. Compared with the bare SiC monolayer, the band gap of the fully hydrogenated system is increased, in comparison with the decrease of the gap in the fully fluorinated case. As a result, the band gap can be tuned from 0.73 to 4.14 eV by the functionalization. In addition to the metal-semiconductor transition, hydrogenation and functionalization also realize a direct-indirect semiconducting transition in the 2 D SiC monolayer. These results provide theoretical guidance for design of photoelectric devices based on the SiC monolayer.
基金supported by the Na-tional Science Foundation of China(41474090)the State Key Laboratory of Earthquake Dynamics(LED 2013A02)
文摘On January 21, 2016, a strong earthquake with a magnitude of Ms6.4 occurred at Menyuan,Qinghai Province of China. In almost the same region, there was another strong earthquake happened in 1986, with similar magnitude and focal mechanism. Based on comprehensive analysis of regional active faults, focal mechanism solutions, precise locations of aftershocks, as well as GPS crustal deformation, we inferred that the Lenglongling active fault dips NE rather than SW as suggested by previous studies. Considering the facts that the 2016 and 1986 Ms6.4 Menyuan earthquakes are closely located with similar focal mechanisms, both of the quakes are on the north side of the Lenglongling Fault and adjacent to the fault, and the fault is dipping NE direction, we suggest that the fault should be the seismogenic structure of the two events. The Lenglongling Fault, as the western segment of the well-known Tianzhu seismic gap in the Qilian-Haiyuan active fault system,is in a relatively active state with frequent earthquakes in recent years, implying a high level of strain accumulation and a high potential of major event. It is also possible that the Lenglongling Fault and its adjacent fault, the Jinqianghe Fault in the Tianzhu seismic gap,are rupturing simultaneously in the future.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10975036 and 61071018)the Guangxi Natural Science Foundation,China (Grant No. 2010GXNSFB013049)
文摘This paper studies the dispersion characteristics of a modified photonic band-gap slow-wave structure with an open boundary by simulation and experiment.A mode launcher with a wheel radiator and a coupling probe is presented to excite a pure TM 01-like mode.The cold test and simulation results show that the TM 01-like mode is effectively excited and no parasitic modes appear.The dispersion characteristics obtained from the cold test are in good agreement with the calculated results.
基金supported by the National Natural Science Foundation of China under Grant No. 60588502
文摘Two kinds of compact electromagnetic band gap (EBG) structures are designed.A two layer compact EBG structure configured with cross spiral shape line inductors and interdigital capacitors is first presented.Because of its significantly enlarged equivalent inductor and capacitance,the period of the lattice is approximately 4.5% of the free space wavelength.By insetting several narrow slits in the ground plane,the bandwidth of the main bandgap is enhanced by nearly 19%.Further effort has been made for designing a three layer compact EBG structure.Simulation results show that its period is reduced by about 26% compared to that of proposed two layer EBG structure,and the bandwidth of the main bandgap is about 3 times as that of the proposed two layer EBG structure.The detailed designs including a two layer compact 3×7 EBG array with and without defect ground plane and the three layer EBG array are given and simulation results are presented.
基金Supported by the Chinese National Key Technologies R&D Program of 11th Five-year Plan (2006BAD27B06)the Fundamental Research Funds for the Central Universities and Education Foundation of Innovative Engineering Key Project of Education Department (707034)
文摘The antioxidant and gap junctional communication(GJC) activities of carotenoids are known to be the two main anticancer mechanisms.Quantitative structure-activity relationship(QSAR) models of the two activities were developed using stepwise regression and multilayer perceptron neural network based on the calculated descriptors of quantum chemistry.The results showed that the significant molecular descriptor related to the antioxidant activity of carotenoids was the HOMO-LUMO energy gap(EHL) and the molecular descriptor related to the GJC was the lowest unoccupied molecular orbital energy(ELUMO).The two models of antioxidant activity both showed good predictive power,but the predictive power of the neural network QSAR model of antioxidant activity was better.In addition,the two GJC models have similar,moderate predictive power.The possible mechanisms of antioxidant activity and GJC of carotenoids were discussed.
基金Project supported by the Major Research Plan of the National Natural Science Foundation of China (Grant No. 90305026)
文摘The transmission properties of compound frequency selective structures with dielectric slab and air gaps were investigated by computation and experimentation.Mechanism analyses were also carried out.Results show that the air gaps have a distinct influence on the transmission properties.Resonant frequency of the structure would increase rapidly when the air gap appears.After the gap gets larger to a specific value,generally 1/5 wavelength corresponding to the resonant frequency,the transmission properties would change periodically with the gap thickness.The change of transmission properties in one period has a close relationship with the dielectric thickness.These results provide a new method for designing a bandpass radome of large incidence angle and low loss with the concept of stealth shield radome.
文摘Firstly,this paper conducts theoretical analysis and current situation analysis,and then proposes research hypotheses.Secondly,using spatial Dubin model and partial differential method,it empirically studies the impact of industrial structure advancement and rationalization on the urban-rural income gap.The results show that:(1)Both industrial structure and urban-rural income gap have significant spatial dependence;(2)The increase in the industrial structure rationalization will narrow the urban-rural income gap in local region,while its spillover effect on neighboring areas is not obvious.(3)The impact of the industrial structure advancement on the urban-rural income gap is not linear.It is first expanded and then narrowed.The industrial structure advancement in the Yangtze River Delta will generally narrow the urban-rural income gap at this stage.Finally,this paper put forward relevant suggestions.
基金Supported by the National Key Research and Development Program of China under Grant No 2016YFA0300300the National Natural Science Foundation of China under Grant No 11334010+1 种基金the National Basic Research Program of China under Grant No2015CB921300the Strategic Priority Research Program(B)of the Chinese Academy of Sciences under Grant No XDB07020300
文摘We carry out detailed momentum-dependent and temperature-dependent measurements on Bi_2Sr_2CaCu_2O_(8+δ)(Bi2212) superconductor in the superconducting and pseudogap states by super-high resolution laser-based angleresolved photoemission spectroscopy. The precise determination of the superconducting gap for the nearly optimally doped Bi2212(T_c= 91 K) at low temperature indicates that the momentum-dependence of the superconducting gap deviates from the standard d-wave form(cos(2Φ)). It can be alternatively fitted by including a high-order term(cos(6Φ)) in which the next nearest-neighbor interaction is considered. We find that the band structure near the antinodal region smoothly evolves across the pseudogap temperature without a signature of band reorganization which is distinct from that found in Bi_2Sr_2CuO_(6+δ) superconductors. This indicates that the band reorganization across the pseudogap temperature is not a universal behavior in cuprate superconductors.These results provide new insights in understanding the nature of the superconducting gap and pseudogap in high-temperature cuprate superconductors.