Low lying excited states of beryllium are calculated with multiconfiguration interaction method. The relativisitic corrections and mass polarization are included. The oscillator strength and radiation rates are also ...Low lying excited states of beryllium are calculated with multiconfiguration interaction method. The relativisitic corrections and mass polarization are included. The oscillator strength and radiation rates are also calculated. Our results are in good agreement with other theoretical data.展开更多
A semi-analytical method to conduct vibro-acoustic analysis of a composite laminated elliptical shell immersed in air is proposed.A variational method and multi-segment technique are used to formulate the dynamic mode...A semi-analytical method to conduct vibro-acoustic analysis of a composite laminated elliptical shell immersed in air is proposed.A variational method and multi-segment technique are used to formulate the dynamic model.The sound radiation of the exterior fluid field is calculated by a spectral Kirchhoff–Helmholtz integral formulation.The variables containing displacements and sound pressure are expanded by the combination of Fourier series and Chebyshev orthogonal polynomials.The collocation points are introduced to construct an algebraic system of acoustic integral equations,where these points are distributed on the roots of Chebyshev polynomials,and the non-uniqueness solution of system is eliminated by a combined Helmholtz integral.Numerical examples for sound radiation problems of composite laminated elliptical shells are presented and individual contributions of the circumferential modes to the acoustical results of composite laminated elliptical shells are also given.The effects of geometric and material parameters on sound radiation of composite laminated elliptical shells are also investigated.展开更多
In this paper, the vibration arid sound radiation of the underwater complexshell-structure which is the cylindrical shell with hemi-spherical shell on the ends are studied bystatistical energy analysis (SEA). The whol...In this paper, the vibration arid sound radiation of the underwater complexshell-structure which is the cylindrical shell with hemi-spherical shell on the ends are studied bystatistical energy analysis (SEA). The whole shell-structure is divided into the four subsystems,and the SEA physical model and power flow balance equations among these subsystems are established.The similitude relations of input power, coupling loss factor and modal density of the subsystemsbetween the complex shell-structure and its scaled-down model are analyzed. According to thesimilitude theory and power flow balance equations, when the immerged shell-structures are excited,the similar relations of spatially averaged vibration response and underwater radiating sound powerare established for the complex shell-structure and its scaled-down model.展开更多
The dynamic mechanical properties of basalt affected by microwave were investigated by performing dynamic compressive tests using the SHPB system.Meanwhile,the thermal damage of the treated basalt was characterized by...The dynamic mechanical properties of basalt affected by microwave were investigated by performing dynamic compressive tests using the SHPB system.Meanwhile,the thermal damage of the treated basalt was characterized by ultrasonic non-destructive testing and nuclear magnetic resonance technology.The results show that with the increase of microwave power and exposure time,the P-wave velocity,dynamic compressive strength and elastic modulus decrease continuously,and the dynamic failure mode tends to be a more complex fracturing.The increase in microwave power and exposure time can enhance the temperature difference and transfer coefficient among minerals,hence intensifying the rock damage induced by thermal shock.展开更多
We find that amplitude-squared squeezing of the photon field is present in a new blackbody, namely, a Kerr- nonlinear blackbody. The squeezing effect decreases as temperature T increases. The amount of the amplitude-s...We find that amplitude-squared squeezing of the photon field is present in a new blackbody, namely, a Kerr- nonlinear blackbody. The squeezing effect decreases as temperature T increases. The amount of the amplitude-squared squeezing in a Kerr-nonlinear blackbody is much larger than the corresponding squeezing in normal blackbody, and the degree of amplitude-squared squeezing is much larger than the amplitude squeezing for the same range of parameters in a Kerr-nonlinear blackbody.展开更多
An operando dual‐beam Fourier transform infrared (DB‐FTIR) spectrometer was successfully developed using a facile method. The DB‐FTIR spectrometer is suitable for the real‐time study of the dynamic surface process...An operando dual‐beam Fourier transform infrared (DB‐FTIR) spectrometer was successfully developed using a facile method. The DB‐FTIR spectrometer is suitable for the real‐time study of the dynamic surface processes involved in gas/solid heterogeneous catalysis under real reaction conditionsbecause it can simultaneously collect reference and sample spectra. The influence of gas‐phasemolecular vibration and heat irradiation at real reaction temperatures can therefore be eliminated.The DB‐FTIR spectrometer was successfully used to follow the transformation of isobutene over nano‐sized HZSM‐5 zeolite under real reaction conditions.展开更多
Using the photon closed orbit theory, the spontaneous emission rate of a polarized atom in a medium between two parallel mirrors is derived and calculated. It is found that the spontaneous emission rate of a polarized...Using the photon closed orbit theory, the spontaneous emission rate of a polarized atom in a medium between two parallel mirrors is derived and calculated. It is found that the spontaneous emission rate of a polarized atom between the mirrors is related to the atomic position and the polarization direction. The results show that in the vicinity of the mirror, the variation of the spontaneous emission rate depends crucially on the atomic polarization direction. With the increase of the polarization angle, the oscillation in the spontaneous emission rate becomes decreased. For the polarization direction parallel to the mirror plane, the oscillation is the greatest; while for the perpendicular polarization direction, the oscillation is nearly vanished. The agreement between our result and the quantum electrodynamics result suggests the correctness of our calculation. This study further verifies that the atomic spontaneous emission process can be effectively controlled by changing the polarization orientation of the atom.展开更多
The incidence of hepatocellular carcinoma(HCC)is increasing in the United States,and 50%-75%o patients with HCC will develop metastatic disease Orbital metastases from HCC are extremely rare.We report the case of a 52...The incidence of hepatocellular carcinoma(HCC)is increasing in the United States,and 50%-75%o patients with HCC will develop metastatic disease Orbital metastases from HCC are extremely rare.We report the case of a 52-year-old male with known metastatic HCC,who presented with severe proptosis and diplopia.An orbital mass was identified on magnetic resonance imaging(MRI)and confirmed to have hypermetabolic activity on positron emission tomography/computed tomography.He received a palliative course of external beam radiation therapy to the right orbit.Intensity modulated radiation therapy (IMRT)was used to allow sparing of critical norma tissues in close proximity to the tumor.One month after completion of IMRT to 58 Gray in 30 fractions delivered over 6 wk,the patient had a complete clinical,radiologic(MRI)and symptomatic response The patient continues to have local control in the orbi 1.7 years after therapy completion.All critical norma structures were kept below the tolerance dose using IMRT,and no toxicities were observed.展开更多
A scheme for one-step preparation of atomic GHZ states in two directly coupled cavities via virtual excitations is proposed.In the whole procedure,the information is carried only in two ground states of A-type atoms, ...A scheme for one-step preparation of atomic GHZ states in two directly coupled cavities via virtual excitations is proposed.In the whole procedure,the information is carried only in two ground states of A-type atoms, while the excited states of atoms and cavity modes are virtually excited,leading the system to be insensitive to atomic spontaneous emission and photon loss.展开更多
There exists strong electromagnetic radiation in inductive energy storage accelerators.It can destroy a measuring device at a distance.By repeated experiments,we found that it is a wide-spectrum electromagnetic wave w...There exists strong electromagnetic radiation in inductive energy storage accelerators.It can destroy a measuring device at a distance.By repeated experiments,we found that it is a wide-spectrum electromagnetic wave with a main frequency of 75MHz.The effector such as coaxial transmission line is effected strongly in short distance.The current in the coaxial transmission line can be measured in Rogowski coils.The strength of field in it is about 500V/m and the peak current is 217mA.The radiation source may be LC oscillating or electric exploding opening switch. Through the experimental research,we think it probably may be caused by the LC oscillating in the circuit when the switches conduct.And its strength is correlated to current change ratio.The change rate in secondary circuit is stronger than in primary circuit.So the radiation generated in secondary circuit is stronger than in primary circuit.It may be a reference for further research in inductive energy storage accelerators and shielding electromagnetic disturbing.展开更多
We demonstrate radiation-pressure-driven mechanical oscillations from high optical quality factor silica microdisk resonators on chip. Mechanical quality factors of 3520 in air and 12540 in vacuum for the fundamental ...We demonstrate radiation-pressure-driven mechanical oscillations from high optical quality factor silica microdisk resonators on chip. Mechanical quality factors of 3520 in air and 12540 in vacuum for the fundamental radial breathing modes are obtained from 73 μm-diarneter silica microdisks with mechanical frequencies of -51 MHz. The measured mechanical oscillation threshold powers for the input light are determined to be 62.5 μW in air and down to 26.6 μW in vacuum.展开更多
This paper develops a numerical model for wheel-rail noise analysis in the time-domain. This model for wheel-rail noise is based on vehicle-track coupling dynamics considering the effect of flexible wheelsets and trac...This paper develops a numerical model for wheel-rail noise analysis in the time-domain. This model for wheel-rail noise is based on vehicle-track coupling dynamics considering the effect of flexible wheelsets and track, and a transient wheel-rail noise prediction method. This model can approximatively characterize the components of vibration and noise in the frequency range up to 3.5 kHz. The wheel-rail forces are calculated and shown in both time and frequency domains by using the vehicle- track coupling dynamic model. Then the vibration and sound of the flexible wheelset are calculated by the transient finite element- boundary element （FE-BE） prediction model at 300 kin/h, in which the effects of random irregularity and discrete supporting excitation are considered. The numerical results calculated by using the present model are discussed. The present model is also used to calculate the effect of corrugation with wavelengths of 40 mm to 300 mm on wheel-rail noise. The numerical results can be useful for academic research and engineering application to railway noise and vibration.展开更多
Thermal and acoustic environments pose severe challenges to find optimal design that exhibits ideal acoustic characteristics the structural design of hypersonic vehicles. One of them is to in a frequency band, which i...Thermal and acoustic environments pose severe challenges to find optimal design that exhibits ideal acoustic characteristics the structural design of hypersonic vehicles. One of them is to in a frequency band, which is discussed in this paper through topology optimization aiming at resonance sound radiation in thermal environments. The sound radiation at resonance fre- quencies is the main component of response, minimization on which is likely to provide a satisfactory design. A bi-material plate subjected to uniform temperature rise and excited by harmonic loading is studied here. Thermal stress is first evaluated and considered as prestress in the following dynamic analysis; radiated sound power is then calculated through Rayleigh inte- gral. Sensitivity analysis is carried out through adjoint method considering the complicated relationship between stress-induced geometric stiffness and design variables. As the resonance frequency is constantly changing during the optimization, its sensi- tivity should be considered. It is also noticed that mode switching may occur, so mode tracking technique is employed in this work. Some numerical examples are finally discussed.展开更多
文摘Low lying excited states of beryllium are calculated with multiconfiguration interaction method. The relativisitic corrections and mass polarization are included. The oscillator strength and radiation rates are also calculated. Our results are in good agreement with other theoretical data.
基金Project(51705537)supported by the National Natural Science Foundation of ChinaProject(2018JJ3661)+2 种基金supported by the Natural Science Foundation of Hunan Province of ChinaProject(ZZYJKT2018-11)supported by State Key Laboratory of High Performance Complex Manufacturing,China。
文摘A semi-analytical method to conduct vibro-acoustic analysis of a composite laminated elliptical shell immersed in air is proposed.A variational method and multi-segment technique are used to formulate the dynamic model.The sound radiation of the exterior fluid field is calculated by a spectral Kirchhoff–Helmholtz integral formulation.The variables containing displacements and sound pressure are expanded by the combination of Fourier series and Chebyshev orthogonal polynomials.The collocation points are introduced to construct an algebraic system of acoustic integral equations,where these points are distributed on the roots of Chebyshev polynomials,and the non-uniqueness solution of system is eliminated by a combined Helmholtz integral.Numerical examples for sound radiation problems of composite laminated elliptical shells are presented and individual contributions of the circumferential modes to the acoustical results of composite laminated elliptical shells are also given.The effects of geometric and material parameters on sound radiation of composite laminated elliptical shells are also investigated.
文摘In this paper, the vibration arid sound radiation of the underwater complexshell-structure which is the cylindrical shell with hemi-spherical shell on the ends are studied bystatistical energy analysis (SEA). The whole shell-structure is divided into the four subsystems,and the SEA physical model and power flow balance equations among these subsystems are established.The similitude relations of input power, coupling loss factor and modal density of the subsystemsbetween the complex shell-structure and its scaled-down model are analyzed. According to thesimilitude theory and power flow balance equations, when the immerged shell-structures are excited,the similar relations of spatially averaged vibration response and underwater radiating sound powerare established for the complex shell-structure and its scaled-down model.
基金supported by the National Natural Science Foundation of China(Nos.51774325,41972283,11972378).
文摘The dynamic mechanical properties of basalt affected by microwave were investigated by performing dynamic compressive tests using the SHPB system.Meanwhile,the thermal damage of the treated basalt was characterized by ultrasonic non-destructive testing and nuclear magnetic resonance technology.The results show that with the increase of microwave power and exposure time,the P-wave velocity,dynamic compressive strength and elastic modulus decrease continuously,and the dynamic failure mode tends to be a more complex fracturing.The increase in microwave power and exposure time can enhance the temperature difference and transfer coefficient among minerals,hence intensifying the rock damage induced by thermal shock.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10174024 and 10474025
文摘We find that amplitude-squared squeezing of the photon field is present in a new blackbody, namely, a Kerr- nonlinear blackbody. The squeezing effect decreases as temperature T increases. The amount of the amplitude-squared squeezing in a Kerr-nonlinear blackbody is much larger than the corresponding squeezing in normal blackbody, and the degree of amplitude-squared squeezing is much larger than the amplitude squeezing for the same range of parameters in a Kerr-nonlinear blackbody.
基金supported by the National Natural Science Foundation of China (21603023)the PetroChina Innovation Foundation, China (2014D-5006-0501)~~
文摘An operando dual‐beam Fourier transform infrared (DB‐FTIR) spectrometer was successfully developed using a facile method. The DB‐FTIR spectrometer is suitable for the real‐time study of the dynamic surface processes involved in gas/solid heterogeneous catalysis under real reaction conditionsbecause it can simultaneously collect reference and sample spectra. The influence of gas‐phasemolecular vibration and heat irradiation at real reaction temperatures can therefore be eliminated.The DB‐FTIR spectrometer was successfully used to follow the transformation of isobutene over nano‐sized HZSM‐5 zeolite under real reaction conditions.
基金Supported by National Natural Science Foundation of China under Grant No. 10604045the University Science & Technology Planning Program of Shandong Province under Grant No. J09LA02the Discipline Construction Fund of Ludong University
文摘Using the photon closed orbit theory, the spontaneous emission rate of a polarized atom in a medium between two parallel mirrors is derived and calculated. It is found that the spontaneous emission rate of a polarized atom between the mirrors is related to the atomic position and the polarization direction. The results show that in the vicinity of the mirror, the variation of the spontaneous emission rate depends crucially on the atomic polarization direction. With the increase of the polarization angle, the oscillation in the spontaneous emission rate becomes decreased. For the polarization direction parallel to the mirror plane, the oscillation is the greatest; while for the perpendicular polarization direction, the oscillation is nearly vanished. The agreement between our result and the quantum electrodynamics result suggests the correctness of our calculation. This study further verifies that the atomic spontaneous emission process can be effectively controlled by changing the polarization orientation of the atom.
文摘The incidence of hepatocellular carcinoma(HCC)is increasing in the United States,and 50%-75%o patients with HCC will develop metastatic disease Orbital metastases from HCC are extremely rare.We report the case of a 52-year-old male with known metastatic HCC,who presented with severe proptosis and diplopia.An orbital mass was identified on magnetic resonance imaging(MRI)and confirmed to have hypermetabolic activity on positron emission tomography/computed tomography.He received a palliative course of external beam radiation therapy to the right orbit.Intensity modulated radiation therapy (IMRT)was used to allow sparing of critical norma tissues in close proximity to the tumor.One month after completion of IMRT to 58 Gray in 30 fractions delivered over 6 wk,the patient had a complete clinical,radiologic(MRI)and symptomatic response The patient continues to have local control in the orbi 1.7 years after therapy completion.All critical norma structures were kept below the tolerance dose using IMRT,and no toxicities were observed.
基金Supported in part by the Natural Science Foundation of China under Grant Nos.10974125,60821004,60878059in part by the Educational Committee of Fujian Province under Grant No.JA09041in part by Fujian Normal University under Grant No.2008100220
文摘A scheme for one-step preparation of atomic GHZ states in two directly coupled cavities via virtual excitations is proposed.In the whole procedure,the information is carried only in two ground states of A-type atoms, while the excited states of atoms and cavity modes are virtually excited,leading the system to be insensitive to atomic spontaneous emission and photon loss.
文摘There exists strong electromagnetic radiation in inductive energy storage accelerators.It can destroy a measuring device at a distance.By repeated experiments,we found that it is a wide-spectrum electromagnetic wave with a main frequency of 75MHz.The effector such as coaxial transmission line is effected strongly in short distance.The current in the coaxial transmission line can be measured in Rogowski coils.The strength of field in it is about 500V/m and the peak current is 217mA.The radiation source may be LC oscillating or electric exploding opening switch. Through the experimental research,we think it probably may be caused by the LC oscillating in the circuit when the switches conduct.And its strength is correlated to current change ratio.The change rate in secondary circuit is stronger than in primary circuit.So the radiation generated in secondary circuit is stronger than in primary circuit.It may be a reference for further research in inductive energy storage accelerators and shielding electromagnetic disturbing.
基金supported by the National Basic Research Program of China(Grant Nos.2012CB921804 and 2011CBA00205)the National Natural Science Foundation of China(Grant Nos.61435007,11104137 and 11321063)
文摘We demonstrate radiation-pressure-driven mechanical oscillations from high optical quality factor silica microdisk resonators on chip. Mechanical quality factors of 3520 in air and 12540 in vacuum for the fundamental radial breathing modes are obtained from 73 μm-diarneter silica microdisks with mechanical frequencies of -51 MHz. The measured mechanical oscillation threshold powers for the input light are determined to be 62.5 μW in air and down to 26.6 μW in vacuum.
基金Project supported by the National Natural Science Foundation of China （Nos. U1434201 and 51475390）, the National Key Technology R＆D Program of China （Nos. 2016YFB1200503-02 and 2016YFB1200506-08）, and the 2015 Doctoral Innovation Funds of Southwest Jiaotong University, China
文摘This paper develops a numerical model for wheel-rail noise analysis in the time-domain. This model for wheel-rail noise is based on vehicle-track coupling dynamics considering the effect of flexible wheelsets and track, and a transient wheel-rail noise prediction method. This model can approximatively characterize the components of vibration and noise in the frequency range up to 3.5 kHz. The wheel-rail forces are calculated and shown in both time and frequency domains by using the vehicle- track coupling dynamic model. Then the vibration and sound of the flexible wheelset are calculated by the transient finite element- boundary element （FE-BE） prediction model at 300 kin/h, in which the effects of random irregularity and discrete supporting excitation are considered. The numerical results calculated by using the present model are discussed. The present model is also used to calculate the effect of corrugation with wavelengths of 40 mm to 300 mm on wheel-rail noise. The numerical results can be useful for academic research and engineering application to railway noise and vibration.
基金supported by the National Natural Science Foundation of China(Grant Nos.11321062,91016008 and 91216107)
文摘Thermal and acoustic environments pose severe challenges to find optimal design that exhibits ideal acoustic characteristics the structural design of hypersonic vehicles. One of them is to in a frequency band, which is discussed in this paper through topology optimization aiming at resonance sound radiation in thermal environments. The sound radiation at resonance fre- quencies is the main component of response, minimization on which is likely to provide a satisfactory design. A bi-material plate subjected to uniform temperature rise and excited by harmonic loading is studied here. Thermal stress is first evaluated and considered as prestress in the following dynamic analysis; radiated sound power is then calculated through Rayleigh inte- gral. Sensitivity analysis is carried out through adjoint method considering the complicated relationship between stress-induced geometric stiffness and design variables. As the resonance frequency is constantly changing during the optimization, its sensi- tivity should be considered. It is also noticed that mode switching may occur, so mode tracking technique is employed in this work. Some numerical examples are finally discussed.
