A fluid sensor based on the surface transverse wave (STW) delay line on ST-cut quartz has been developed and tested in a large number of fluids with different viscosity and permittivity levels.Influence of fluid mech...A fluid sensor based on the surface transverse wave (STW) delay line on ST-cut quartz has been developed and tested in a large number of fluids with different viscosity and permittivity levels.Influence of fluid mechanical and electrical properties on the sensor's response has been determined and the sensor's performance has been compared with a bulk acoustic wave (BAW) viscosity sensor.The result shows that the viscosity sensitivity of the developed STW sensor represented by the signal to noise ratio is lower than that of a 5 MHz BAW sensor.Applications of the sensor in detecting the quality of industrial fluids are discussed.展开更多
Through two methods, we investigate the solitary and periodic wave solutions of the differential equation describing a nonlinear coupled two-dimensional discrete electrical lattice. The fixed points of our model equat...Through two methods, we investigate the solitary and periodic wave solutions of the differential equation describing a nonlinear coupled two-dimensional discrete electrical lattice. The fixed points of our model equation are examined and the bifurcations of phase portraits of this equation for various values of the front wave velocity are presented. Using the sineGordon expansion method and classic integration, we obtain exact transverse solutions including breathers, bright solitons,and periodic solutions.展开更多
The longitudinal wave term within Faraday’s law of electromagnetic induction (Faraday’s law) underwent recovery to ensure its suitability for theoretical derivation of the equation governing longitudinal electromagn...The longitudinal wave term within Faraday’s law of electromagnetic induction (Faraday’s law) underwent recovery to ensure its suitability for theoretical derivation of the equation governing longitudinal electromagnetic (LEM) waves. The revised Maxwell’s equations include the crucial parameters being the attenuation time constants of magnetic vortex potential and electric vortex potential generated by external electromagnetic field within the propagation medium. Specific expressions for them are obtained through theoretical analysis. Subsequently, a model for propagating magnetic P-wave generated by the superposition of a left-handed photo and a right-handed photon in a vacuum is formulated based on reevaluated total current law and revised Faraday’s law, covering wave equations, energy equation, as well as propagation mode involving mutual induction and conversion between scalar magnetic field and vortex electric field. Furthermore, through theoretical derivations centered around magnetic P-wave, evidence was presented regarding its ability to absorb huge free energy through the entangled interaction between zero-point vacuum energy field and the torsion field produced by the vortex electric field.展开更多
A 2.5-dimensional method in frequency wave-number domain is developed to investigate the mode waves in a deviated borehole penetrating a transversely isotropic formation. The phase velocity dispersion characteristics ...A 2.5-dimensional method in frequency wave-number domain is developed to investigate the mode waves in a deviated borehole penetrating a transversely isotropic formation. The phase velocity dispersion characteristics of the fast and slow flexural mode waves excited by a dipole source are computed accurately at various deviation angles for both hard and soft formations. The sensitivities of the flexural mode waves to all elastic constants in a transversely isotropic formation are calculated. Numerical results show that, for a soft formation, the fast flexural mode wave is dominated by c66 at high deviation angles and low frequencies, while the slow flexural mode wave is dominated by c44 at the same conditions. Waveforms in time domain are also presented to support the conclusions.展开更多
A low-frequency multi-mode ultrasonic Lamb wave method suitable for character- izing the thickness, the density and the elastic constants of the ultra-thin transversely isotropic laminate composite is presented. The &...A low-frequency multi-mode ultrasonic Lamb wave method suitable for character- izing the thickness, the density and the elastic constants of the ultra-thin transversely isotropic laminate composite is presented. The 'ultra-thin' here means that the thickness of the plate is much less than the wavelength of the ultrasonic wave so that the echoes from the front and back faces of the plate can't be separated in the time domain. The dispersion equations for the low frequency ultrasonic Lamb waves with the propagation directions parallel and vertical to the fiber direction are derived. In conjunction with the least square algorithm method, the secant algorithm is used to estimate the parameters of the ultra-thin fiber-reinforced composite layer. The evaluation errors and the sensitivity of the method to different paramters of the thin composite are analyzed. The technique has been used to characterize the ultra-thin grass fiber reinforced PES composite with thickness down to ten percents of the ultrasonic wavelength. It is observed that the agreement between the nominal and the estimation values is reasonably good.展开更多
During the last decade, phase-conjugation mirror (PCM) and phase-conjugation resonator (PCR) have interest to many authors in that they can be used to improve the quality of laser beams. For a laser using conventional...During the last decade, phase-conjugation mirror (PCM) and phase-conjugation resonator (PCR) have interest to many authors in that they can be used to improve the quality of laser beams. For a laser using conventional optical resontors, we展开更多
Based on the first part of this paper (Science in China, 33(1990), 982—995), further research has been done on quasi-equivalence relation and asymmetrical character of axisymmetrical phase-conjugatlon resonator(PCR)....Based on the first part of this paper (Science in China, 33(1990), 982—995), further research has been done on quasi-equivalence relation and asymmetrical character of axisymmetrical phase-conjugatlon resonator(PCR). A series of calculations for axisymmetrical PCR(hundreds of transverse modes in 66 axisymmetrical PCRs) have been carried out, and the results are compared with those of corresponding conventional laser resonators. Fundamental properties of the transverse modes (TEMs) in PCR are summarized. This makes possible a rough estimation of the properties of various TEMs in these simple PCR, including different geometrical structures.展开更多
Based on 'the matrix theory for the propagation of a scalar light wave in a system consisting of plane screens (cylindrical coordinates)' proposed by one of the authors (1981), the propagation of the self-cons...Based on 'the matrix theory for the propagation of a scalar light wave in a system consisting of plane screens (cylindrical coordinates)' proposed by one of the authors (1981), the propagation of the self-consistent field in PCR is analyzed, and a matrix eigen-equation of the self-consistent field is presented. By solving the eigen-equation, the axisymmetrical PCR with finite aperture is calculated, and the diffraction losses, phase shifts, relative amplitude and phase distributions on each mirror surface of various order transverse modes (including high-order modes, whose l≥2, p≥1) are introduced.A quasi-equivalence relation of PCR is also given. According to this relation, some characteristics (as the diffraction loss, the field distribution on the surface of spherical mirror) of all transverse modes in a PCR are just the same as those in some of the other PCR with different g_1.Some examples of calculation results are also given. They show that (ⅰ) the convengence of the above-mentioned equation is very good, (ⅱ) the calculation results with very high precision can be obtained practically, and the characteristics of TEM with very small or large losses can also be calculated precisly and (ⅲ) the choice of the reference light field does not affect correctness of the theory but affects the amount of calculation.Only the PCR with only one PCM being one of the two endreflectors of resonators is discussed, and the effect of response time of the PCM is ignored in this paper.展开更多
In this paper Substrate Integrated Waveguide-basedfiltenna operating at Ku band is proposed.The model is designed on a low loss dielectric substrate having a thickness of 0.508 mm and comprises of shorting vias along ...In this paper Substrate Integrated Waveguide-basedfiltenna operating at Ku band is proposed.The model is designed on a low loss dielectric substrate having a thickness of 0.508 mm and comprises of shorting vias along two edges of the substrate walls.To realize a bandpassfilter,secondary shorting vias are placed close to primary shorting vias.The dimension and position of the vias are carefully analyzed for Ku band frequencies.The model is fabricated on Roger RT/duroid 5880 and the performance characteristics are measured.The proposed model achieves significant impedance characteristics with wider bandwidth in the Ku band.The model also achieves a maximum gain of 7.46 dBi in the operating band thus making it suitable for Ku-band applications.Substrate Integrated Waveguide(SIW)Structures possess most of the advantages over conventional radiofrequency waveguides since they have high power management capacity with self-consistent electrical shielding.The most noteworthy advantage of SIW,it can able to integrate all the components on the same substrate,both passive and active components.展开更多
文章参照标准IEC 61967-2设计了一个横电磁波(transverse electric and magnetic field,TEM)小室,介绍了TEM小室的整体设计方法,实现了TEM小室良好的阻抗匹配特性,并研究了2种改进方法用于抑制TEM小室高次模和谐振的产生;在三维电磁仿...文章参照标准IEC 61967-2设计了一个横电磁波(transverse electric and magnetic field,TEM)小室,介绍了TEM小室的整体设计方法,实现了TEM小室良好的阻抗匹配特性,并研究了2种改进方法用于抑制TEM小室高次模和谐振的产生;在三维电磁仿真软件中建立了新型TEM小室的三维仿真模型,并计算了新型TEM小室的S参数和电压驻波比(voltage standing wave ratio,VSWR)。计算结果表明,2种新型TEM小室的上限可用频率可提高到3GHz。展开更多
针对目前火花塞点火系统燃烧速度慢、燃烧效率低下等问题,提出了一种利用微波谐振腔实现多点点火的方法。通过理论分析和模拟仿真、优化,确定了横磁振荡模式(TM010)谐振腔的尺寸及其发生谐振时的场强分布。同时采用高速相机和压力传感器...针对目前火花塞点火系统燃烧速度慢、燃烧效率低下等问题,提出了一种利用微波谐振腔实现多点点火的方法。通过理论分析和模拟仿真、优化,确定了横磁振荡模式(TM010)谐振腔的尺寸及其发生谐振时的场强分布。同时采用高速相机和压力传感器,对点火燃烧过程进行可视化分析和燃烧压力特性分析。结果表明:与传统的火花塞的点火方法相比,在实验气压为200 k Pa的条件下,这种方法可以缩短到达压力峰值的时间约15%,并且可以使峰值压力提高约5%。因此,这种方法能够实现多点点火。展开更多
文摘A fluid sensor based on the surface transverse wave (STW) delay line on ST-cut quartz has been developed and tested in a large number of fluids with different viscosity and permittivity levels.Influence of fluid mechanical and electrical properties on the sensor's response has been determined and the sensor's performance has been compared with a bulk acoustic wave (BAW) viscosity sensor.The result shows that the viscosity sensitivity of the developed STW sensor represented by the signal to noise ratio is lower than that of a 5 MHz BAW sensor.Applications of the sensor in detecting the quality of industrial fluids are discussed.
文摘Through two methods, we investigate the solitary and periodic wave solutions of the differential equation describing a nonlinear coupled two-dimensional discrete electrical lattice. The fixed points of our model equation are examined and the bifurcations of phase portraits of this equation for various values of the front wave velocity are presented. Using the sineGordon expansion method and classic integration, we obtain exact transverse solutions including breathers, bright solitons,and periodic solutions.
文摘The longitudinal wave term within Faraday’s law of electromagnetic induction (Faraday’s law) underwent recovery to ensure its suitability for theoretical derivation of the equation governing longitudinal electromagnetic (LEM) waves. The revised Maxwell’s equations include the crucial parameters being the attenuation time constants of magnetic vortex potential and electric vortex potential generated by external electromagnetic field within the propagation medium. Specific expressions for them are obtained through theoretical analysis. Subsequently, a model for propagating magnetic P-wave generated by the superposition of a left-handed photo and a right-handed photon in a vacuum is formulated based on reevaluated total current law and revised Faraday’s law, covering wave equations, energy equation, as well as propagation mode involving mutual induction and conversion between scalar magnetic field and vortex electric field. Furthermore, through theoretical derivations centered around magnetic P-wave, evidence was presented regarding its ability to absorb huge free energy through the entangled interaction between zero-point vacuum energy field and the torsion field produced by the vortex electric field.
基金supported by the National Natural Science Foundation of China(Grant No.11134011)the National R&D Projects for Key Scientific Instruments(Grant No.ZDYZ2012-1-07)the"12th Five-Year Plan"Period for Informatization Project in Supercomputing Key Demonstration,Chinese Academy of Sciences(Grant No.XXH12503-02-02-2(07))
文摘A 2.5-dimensional method in frequency wave-number domain is developed to investigate the mode waves in a deviated borehole penetrating a transversely isotropic formation. The phase velocity dispersion characteristics of the fast and slow flexural mode waves excited by a dipole source are computed accurately at various deviation angles for both hard and soft formations. The sensitivities of the flexural mode waves to all elastic constants in a transversely isotropic formation are calculated. Numerical results show that, for a soft formation, the fast flexural mode wave is dominated by c66 at high deviation angles and low frequencies, while the slow flexural mode wave is dominated by c44 at the same conditions. Waveforms in time domain are also presented to support the conclusions.
基金the National Natural Science Foundation of China (No. 69631020) and theOffice of Naval Research of America (00014-93-1-0340).
文摘A low-frequency multi-mode ultrasonic Lamb wave method suitable for character- izing the thickness, the density and the elastic constants of the ultra-thin transversely isotropic laminate composite is presented. The 'ultra-thin' here means that the thickness of the plate is much less than the wavelength of the ultrasonic wave so that the echoes from the front and back faces of the plate can't be separated in the time domain. The dispersion equations for the low frequency ultrasonic Lamb waves with the propagation directions parallel and vertical to the fiber direction are derived. In conjunction with the least square algorithm method, the secant algorithm is used to estimate the parameters of the ultra-thin fiber-reinforced composite layer. The evaluation errors and the sensitivity of the method to different paramters of the thin composite are analyzed. The technique has been used to characterize the ultra-thin grass fiber reinforced PES composite with thickness down to ten percents of the ultrasonic wavelength. It is observed that the agreement between the nominal and the estimation values is reasonably good.
文摘During the last decade, phase-conjugation mirror (PCM) and phase-conjugation resonator (PCR) have interest to many authors in that they can be used to improve the quality of laser beams. For a laser using conventional optical resontors, we
文摘Based on the first part of this paper (Science in China, 33(1990), 982—995), further research has been done on quasi-equivalence relation and asymmetrical character of axisymmetrical phase-conjugatlon resonator(PCR). A series of calculations for axisymmetrical PCR(hundreds of transverse modes in 66 axisymmetrical PCRs) have been carried out, and the results are compared with those of corresponding conventional laser resonators. Fundamental properties of the transverse modes (TEMs) in PCR are summarized. This makes possible a rough estimation of the properties of various TEMs in these simple PCR, including different geometrical structures.
文摘Based on 'the matrix theory for the propagation of a scalar light wave in a system consisting of plane screens (cylindrical coordinates)' proposed by one of the authors (1981), the propagation of the self-consistent field in PCR is analyzed, and a matrix eigen-equation of the self-consistent field is presented. By solving the eigen-equation, the axisymmetrical PCR with finite aperture is calculated, and the diffraction losses, phase shifts, relative amplitude and phase distributions on each mirror surface of various order transverse modes (including high-order modes, whose l≥2, p≥1) are introduced.A quasi-equivalence relation of PCR is also given. According to this relation, some characteristics (as the diffraction loss, the field distribution on the surface of spherical mirror) of all transverse modes in a PCR are just the same as those in some of the other PCR with different g_1.Some examples of calculation results are also given. They show that (ⅰ) the convengence of the above-mentioned equation is very good, (ⅱ) the calculation results with very high precision can be obtained practically, and the characteristics of TEM with very small or large losses can also be calculated precisly and (ⅲ) the choice of the reference light field does not affect correctness of the theory but affects the amount of calculation.Only the PCR with only one PCM being one of the two endreflectors of resonators is discussed, and the effect of response time of the PCM is ignored in this paper.
文摘In this paper Substrate Integrated Waveguide-basedfiltenna operating at Ku band is proposed.The model is designed on a low loss dielectric substrate having a thickness of 0.508 mm and comprises of shorting vias along two edges of the substrate walls.To realize a bandpassfilter,secondary shorting vias are placed close to primary shorting vias.The dimension and position of the vias are carefully analyzed for Ku band frequencies.The model is fabricated on Roger RT/duroid 5880 and the performance characteristics are measured.The proposed model achieves significant impedance characteristics with wider bandwidth in the Ku band.The model also achieves a maximum gain of 7.46 dBi in the operating band thus making it suitable for Ku-band applications.Substrate Integrated Waveguide(SIW)Structures possess most of the advantages over conventional radiofrequency waveguides since they have high power management capacity with self-consistent electrical shielding.The most noteworthy advantage of SIW,it can able to integrate all the components on the same substrate,both passive and active components.
文摘文章参照标准IEC 61967-2设计了一个横电磁波(transverse electric and magnetic field,TEM)小室,介绍了TEM小室的整体设计方法,实现了TEM小室良好的阻抗匹配特性,并研究了2种改进方法用于抑制TEM小室高次模和谐振的产生;在三维电磁仿真软件中建立了新型TEM小室的三维仿真模型,并计算了新型TEM小室的S参数和电压驻波比(voltage standing wave ratio,VSWR)。计算结果表明,2种新型TEM小室的上限可用频率可提高到3GHz。
文摘针对目前火花塞点火系统燃烧速度慢、燃烧效率低下等问题,提出了一种利用微波谐振腔实现多点点火的方法。通过理论分析和模拟仿真、优化,确定了横磁振荡模式(TM010)谐振腔的尺寸及其发生谐振时的场强分布。同时采用高速相机和压力传感器,对点火燃烧过程进行可视化分析和燃烧压力特性分析。结果表明:与传统的火花塞的点火方法相比,在实验气压为200 k Pa的条件下,这种方法可以缩短到达压力峰值的时间约15%,并且可以使峰值压力提高约5%。因此,这种方法能够实现多点点火。
