By religiously adhering to physics in spacetime and taking the final verdict of N.D. Mermin’s Ithaca interpretation of quantum mechanics seriously, Hardy’s paradox is completely resolved. It is then concluded that l...By religiously adhering to physics in spacetime and taking the final verdict of N.D. Mermin’s Ithaca interpretation of quantum mechanics seriously, Hardy’s paradox is completely resolved. It is then concluded that logical and mathematically consistent physical theories must be put in spacetime related formalism such as noncommutative geometry and E-infinity theory to avoid quantum paradoxes. At a minimum, we should employ the philosophy behind consistent quantum interpretation such as that of the famous Ithaca interpretation of D. Mermin.展开更多
A catalog of M stars has been published from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope data release 7(LAMOST DR7).We cross-matched the LAMOST M catalog with Kepler,Kepler 2(K2)and Transiting Exopla...A catalog of M stars has been published from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope data release 7(LAMOST DR7).We cross-matched the LAMOST M catalog with Kepler,Kepler 2(K2)and Transiting Exoplanet Survey Satellite(TESS)surveys.We obtained the light curves from the Kepler and TESS surveys.We detected 20,047 flare events from 4053 M stars and calculated their durations,amplitudes,and energies.We analyzed the distribution of the flare durations and energies.The distributions of flare duration for Kepler,K2 and TESS peak are at 3–3.5 hr,4–6 hr and 1–1.5 hr,respectively.This may be the result of the different cadences for the three data sets.The highest regions of the flare energies of Kepler,K2 and TESS are 32–32.5,32–32.5 and31–31.5 erg in Log format,respectively.A linear relationship between flare duration and energy emerges from our analysis.The ratio of flare duration to total observational time is approximately 0.2%–0.3%for the Kepler,K2 and TESS surveys.The occurrence rate of a star with a flare event increases from the M0 to M4 subtypes.We also determined the spatial distribution of the flare rate of M stars in the Milky Way.It seems that the flare rate decreases as the vertical height increases.The power index of the flare energies is in the region of 1.53–2.32,which is similar to previous result for solar type star(2.0).Further,we examined the relationship between the flare amplitude and chromospheric intensity.The flare activity increases rapidly with the increase in the HαEW at the lower values(less approximately 2?)and it increases slowly at the higher values.展开更多
With the use of variational method of Pekar type, this paper studied the energy levels of magnetopolaron in quantum wire with strong electron phonon interaction. The magnetopolaron binding energy in the ground state a...With the use of variational method of Pekar type, this paper studied the energy levels of magnetopolaron in quantum wire with strong electron phonon interaction. The magnetopolaron binding energy in the ground state and in the excited state, as well as the resonance frequency of magnetopolaron were calculated. Their dependence on the cyclotron frequency and the confinement strength of quantum wire was depicted. The limiting case of bulk type and strict two dimensional type was discussed.展开更多
A limited-area primitive equation model is used to study the role of the β-effect and a uniform current on tropical cyclone (TC) intensity.It is found that TC intensity is reduced in a non-quiescent environment compa...A limited-area primitive equation model is used to study the role of the β-effect and a uniform current on tropical cyclone (TC) intensity.It is found that TC intensity is reduced in a non-quiescent environment compared with the case of no uniform current.On an f-plane,the rate of intensification of a tropical cyclone is larger than that of the uniform flow.A TC on a β-plane intensifies slower than one on an f-plane.The main physical characteristic that distinguishes the experiments is the asymmetric thermodynamic (including convective) and dynamic structures present when either a uniform flow or β-effect is introduced.But a fairly symmetric TC structure is simulated on an f-plane.The magnitude of the warm core and the associated subsidence are found to be responsible for such simulated intensity changes.On an f-plane,the convection tends to be symmetric,which results in strong upper-level convergence near the center and hence strong forced subsidence and a very warm core.On the other hand,horizontal advection of temperature cancels part of the adiabatic heating and results in less warming of the core,and hence the TC is not as intense.This advective process is due to the tilt of the vortex as a result of the β-effect.A similar situation occurs in the presence of a uniform flow.Thus,the asymmetric horizontal advection of temperature plays an important role in the temperature distribution.Dynamically,the asymmetric angular momentum (AM) flux is very small on an f-plane throughout the troposphere.However,the total AM exports at the upper levels for a TC either on aβ-plane or with a uniform flow environment are larger because of an increase of the asymmetric as well as symmetric AM export on the plane at radii >450 km,and hence there is a lesser intensification.展开更多
Aimed at the difficulty in finding an efficient method to depress and recognize chaff in both time and frequency domain,this paper tries to recognize chaff and target such as warship in polarization domain under the t...Aimed at the difficulty in finding an efficient method to depress and recognize chaff in both time and frequency domain,this paper tries to recognize chaff and target such as warship in polarization domain under the theoretical analysis of the polarization scattering cross section of chaff.In order to find target more exactly,non-linear polarization transformation and polarization smoothness are applied to process the polarization information of chaff and ship target.The resulting recognition is proved to be effective by simulation.展开更多
The method of empirical mode decomposition(EMD) was used for the signal processing and featureing of acoustic target of battle field. According to the signal's characteristics of different targets, some feature ve...The method of empirical mode decomposition(EMD) was used for the signal processing and featureing of acoustic target of battle field. According to the signal's characteristics of different targets, some feature vectors in token of the target properties were constructed and abstracted. In the basis of feature abstracting and statistic analysis for large amount of sample signal of the targets, using the maximum subjection classification method based on the fuzzy synthesis judgment, the three typical acoustic target helicopter, tank and traffic vehicle were recognized.展开更多
Magnetic Barkhausen Noise (MBN) is a phenomenon of electromagnetic energy emission due to the movement of magnetic domain walls inside ferromagnetic materials when they are locally magnetized by an alternating magneti...Magnetic Barkhausen Noise (MBN) is a phenomenon of electromagnetic energy emission due to the movement of magnetic domain walls inside ferromagnetic materials when they are locally magnetized by an alternating magnetic field. According to Faraday’s law of electromagnetic induction, the noise can be received by the coil attached to the surface of the material being magnetized and the noise carries the message of the characteristics of the material such as stresses, hardness, phase content, etc. Based on the characteristic of the noise, research about the relationship between the welding stresses in the welding assembly and the noise, the fatigue damage of the plate structure and the noise, and the influence of heat treatment and the variation of phase content to the noise are carried out in this paper.展开更多
The compositions Ce0.8-xSm0.2O2-δ(X=0, 0.02, 0.04, 0.06) were prepared through the sol–gel route. The effect of Pr addition on the crystal structure, densification and thermal expansion of Ce0.8Sm0.2O2-δ was studie...The compositions Ce0.8-xSm0.2O2-δ(X=0, 0.02, 0.04, 0.06) were prepared through the sol–gel route. The effect of Pr addition on the crystal structure, densification and thermal expansion of Ce0.8Sm0.2O2-δ was studied. The phase identification and morphology was studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). X-ray diffraction analysis showed that all the samples exhibit a fluorite structure. The lattice parameters? were determined by X-ray powder diffraction. Lattice parameters and volume of the unit cell increases with Pr doping. Density of the all samples is more than 90% of theoretical density. The thermal expansion was measured using dilatometric technique in the temperature range 30–1000°C. It was observed that the thermal expansion increased linearly with increasing temperature for all the samples.展开更多
The present short paper is concerned with accurate explanation as well as quantification of the so called missing dark energy of the cosmos. It was always one of the main objectives of any successful general theory of...The present short paper is concerned with accurate explanation as well as quantification of the so called missing dark energy of the cosmos. It was always one of the main objectives of any successful general theory of high energy particle physics and quantum cosmology to keep non-physical negative norms, the so called ghosts completely out of that theory. The present work takes the completely contrary view by admitting these supposedly spurious states as part of the physical Hilbert space. It is further shown that rethinking the ghost free condition with the two critical spacetime dimensions D<sub>1</sub> = 26 and D<sub>2</sub> = 25 together with the corresponding intercept a<sub>1</sub> = 1 and a<sub>2</sub> ≤ 1 respectively and in addition imposing, as in Gross et al. heterotic superstrings, an overall 496 dimensional exceptional Lie symmetry group, then one will discover that there are two distinct types of energy. The first is positive norm ordinary energy connected to the zero set quantum particles which is very close to the measured ordinary energy density of the cosmos, namely E(O) = mc<sup>2</sup>/22. The second is negative norm (i.e. ghost) energy connected to the empty set quantum wave and is equal to the conjectured dark energy density of the cosmos E(D) = mc<sup>2</sup> (21/22) presumed to be behind the observed accelerated cosmic expansion. That way we were able to not only explain the physics of dark energy without adding any new concepts or novel additional ingredients but also we were able to compute the dark energy density accurately and in full agreement with measurements and observations.展开更多
The collision dynamics and fragmentation process of molecule by highly charged ionimpact for single electron capture processes at the low energies below 1 keV/u were studied. Thecollision energy dependence of the reco...The collision dynamics and fragmentation process of molecule by highly charged ionimpact for single electron capture processes at the low energies below 1 keV/u were studied. Thecollision energy dependence of the recoil momentum was obtained experimentally and compared itwith those calculated by a theoretical model using a deflection function with polarization potential.A fairly good agreement between the measured and calculated results was reached. This suggeststhat the polarization potential plays a crucial role in the low-energy region.展开更多
The redshift and the blueshift of spectral lines in gravitational fields of photon stars are studied when the observing and emitting points of the spectral lines locate at different positions. And the motion of mass-p...The redshift and the blueshift of spectral lines in gravitational fields of photon stars are studied when the observing and emitting points of the spectral lines locate at different positions. And the motion of mass-points is also studied. The studies show that the redshift and the blueshift of spectral lines in gravitational fields of photon stars can be arbitrarily positive, and the motion of mass-points in gravitational fields of photon stars can be used to determine the mass of photon stars.展开更多
A photon avalanche phenomenon was observed in Er3+ and Li+codoped ZnO nanocrystals at room temperature under excitation around 976 nm.When the excitation power was over 120 mW/mm2,we found that the upconversion of red...A photon avalanche phenomenon was observed in Er3+ and Li+codoped ZnO nanocrystals at room temperature under excitation around 976 nm.When the excitation power was over 120 mW/mm2,we found that the upconversion of red emission was generated by a four-photon absorption process and might be caused by intense interaction between neighboring Er3+ ions:4F7/2+4I11/2→ 24F9/2.When the excitation power was over the threshold of 240 mW/mm2,the green emission avalanche upconversion was generated through an excited-state absorption process:4F9/2+photon → 2H9/2.The study extends the knowledge of this ion to a wider range of upconversion application.展开更多
Considering the interaction between the electromagnetic field and matter field, a concise method is used to calculate the ground-state energy of the interacting system. With the assumption of squeezed-like state, a ne...Considering the interaction between the electromagnetic field and matter field, a concise method is used to calculate the ground-state energy of the interacting system. With the assumption of squeezed-like state, a new vacuum state is obtained for the inte racting system. The energy of the new vacuum state is obviously lower than that of unperturbed vacu um state. Based on the new vacuum state, the correction to the Casimir force is obtained. The r esult shows that the contribution of the interaction is a repulsive one and the Casimir effect is attributed to both electromagnetic field and matter field. On the basis of the obtained results, th e recent experimental data can be explained reasonably.展开更多
The radiation dose received by patients undergoing chest radiography was included. 200 patients who attended these investigations in 10 hospitals in Iran were randomly selected from all ages groups and both female and...The radiation dose received by patients undergoing chest radiography was included. 200 patients who attended these investigations in 10 hospitals in Iran were randomly selected from all ages groups and both female and male. Critically ill patients were excluded.This paper presents the work, which was implemented on 200 patients and evaluated using the entrance skin dose (ESD) in the posterior anterior (PA) chest projection measured directly at the center of the X-ray field. In addition, the machine room, and dark room parameters, as well as work practices and repeat rates were studied. The quality control (QC) parameters and the ESD before and after QC were evaluated utilizing an anthropomorphic phantom to define the optimal exposure condition at all hospitals. This research shows that after using the QC parameters and after optimization of the exposure conditions, the ESD was decreased by 42% on average. Also the quality of the radiographs generally increased. The reported method is easily implemented in any clinical situation where optimization of chest radiography is needed.展开更多
We analyze the most powerful X-ray outbursts from neutron stars in eleven Magellanic high-mass X-ray binaries and three pulsating ultraluminous X-ray sources. Most of the outbursts rise to L_(max) which is about the l...We analyze the most powerful X-ray outbursts from neutron stars in eleven Magellanic high-mass X-ray binaries and three pulsating ultraluminous X-ray sources. Most of the outbursts rise to L_(max) which is about the level of the Eddington luminosity, while the remaining more powerful outbursts also appear to recognize that limit when their emissions are assumed to be anisotropic and beamed toward our direction. We use the measurements of pulsar spin periods P_S and their derivatives P_S to calculate the X-ray luminosities L_p in their faintest accreting("propeller-line") states. In five cases with unknown P_S, we use the lowest observed X-ray luminosities, which only adds to the heterogeneity of the sample. Then we calculate the ratios L_p/L_(max) and we obtain an outstanding confluence of theory and observations from which we conclude that work done on both fronts is accurate and the results are trustworthy: sources known to reside on the lowest Magellanic propeller line are all located on/near that line, whereas other sources jump higher and reach higher-lying propeller lines. These jumps can be interpreted in only one way, higher-lying pulsars have stronger surface magnetic fields in agreement with previous empirical results in whichP_S and L_p values were not used.展开更多
PB Phase Coherent States are very important quantum states in quantum optics. In order to investigate the amplitude-Nth-power squeezing of PB Phase Coherent States, we introduce the algebraic properties of the PB phas...PB Phase Coherent States are very important quantum states in quantum optics. In order to investigate the amplitude-Nth-power squeezing of PB Phase Coherent States, we introduce the algebraic properties of the PB phase operator and the PB Phase Coherent States which are constructed by PB phase theory. We applied amplitude-Nth-power squeezing theory to define the Amplitude-Nth-Power Squeezing of PB Phase Coherent States and investigate the characteristic of the amplitude-Nth-power squeezing of PB Phase Coherent States. We obtained surprising results, in that the results were different from the other quantum states. As for |Z〉(PB Phase Coherent State), the results show that when Z is a real number there only exists amplitude-Nth-power squeezing of component; when Z is a complex number, there exists amplitude-Nth-power squeezing of component and component; when Z is a pure imaginary number, if N is odd, then there does not exist amplitude-Nth-power squeezing of component, but there exists amplitude-Nth-power squeezing of component and if N is even, then there exists amplitude-Nth-power squeezing of component, but there does not exist amplitude-Nth-power squeezing of component.展开更多
Taking into account correlations in a layered two-dimensional(2D)Fermi liquid,aCoulomb-type interaction induces pairing if particle-hole excitations are taken into account.The quasi-particle pairing force is analogo...Taking into account correlations in a layered two-dimensional(2D)Fermi liquid,aCoulomb-type interaction induces pairing if particle-hole excitations are taken into account.The quasi-particle pairing force is analogous to the resonating valence bond(RVB)of elec-trons in a hydrogen or positronium molecule-like structure.It is turned out that scatteringdiagrams from this model allow to evaluate the vertex function Γ.T<sub>c</sub> is hence calculated byusing the pole condition Γ<sup>-1</sup>=0.It has been found out that T<sub>c</sub> can reach quite high values andgives rise to the bell shape,and is related to the particle density,interlayer distance,dielec-tric constant and band mass.PACS numbers:74.65.+n,71.45.Gm.,74.70.Jm.,71.45.Lr.展开更多
The encoding/decoding scheme based on Fiber Bragg Grating (FBG) for Optical Code Division Multiple Access (OCDMA) system is analyzed and the whole process from transmitting end to receiving end is researched in detail...The encoding/decoding scheme based on Fiber Bragg Grating (FBG) for Optical Code Division Multiple Access (OCDMA) system is analyzed and the whole process from transmitting end to receiving end is researched in detail. The mathematical mode including signal transmission, summing, receiving and recovering are established respectively. One of the main sources of Bit Error Rate (BER) of OCDMA system based on FBGs is the unevenness of signal power spectrum, which leads to the chip powers unequal with each other. The Signal to Interfere Ratio (SIR) and BER performance of the system are studied and simulated at the case with uneven distribution of chips' powers.展开更多
Based on three typical mechanisms (second-order, third-order and competitive mechanisms) for the curing reactions of the epoxy resins with amines, a pair of the kinetic equations (for primary and secondary aminations)...Based on three typical mechanisms (second-order, third-order and competitive mechanisms) for the curing reactions of the epoxy resins with amines, a pair of the kinetic equations (for primary and secondary aminations) was presented to explain the uniformity and relationship among the three different kinetic mechanisms of the reactions. The presented macro-equations were deduced from the kinetic micro-equations by the statistics method. And the constitutive equations were verified by experimental data at different reaction times and temperatures (95°C, 60°C and 39°C), taking diglycidyl ether of bisphenol A (DGEBA) /ethyleneamine (EA) as a model.展开更多
文摘By religiously adhering to physics in spacetime and taking the final verdict of N.D. Mermin’s Ithaca interpretation of quantum mechanics seriously, Hardy’s paradox is completely resolved. It is then concluded that logical and mathematically consistent physical theories must be put in spacetime related formalism such as noncommutative geometry and E-infinity theory to avoid quantum paradoxes. At a minimum, we should employ the philosophy behind consistent quantum interpretation such as that of the famous Ithaca interpretation of D. Mermin.
基金LAMOST is a National Major Scientific Project built by the Chinese Academy of Sciencesprovided by the National Development and Reform Commission+3 种基金the financial supports obtained from the NSFC No.11963002the fostering project of Guizhou University with No.201911the science research grants from the China Manned Space Project with No.CMS-CSST-2021-B07the Natural Science Foundation of Guizhou Province with No.2022164。
文摘A catalog of M stars has been published from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope data release 7(LAMOST DR7).We cross-matched the LAMOST M catalog with Kepler,Kepler 2(K2)and Transiting Exoplanet Survey Satellite(TESS)surveys.We obtained the light curves from the Kepler and TESS surveys.We detected 20,047 flare events from 4053 M stars and calculated their durations,amplitudes,and energies.We analyzed the distribution of the flare durations and energies.The distributions of flare duration for Kepler,K2 and TESS peak are at 3–3.5 hr,4–6 hr and 1–1.5 hr,respectively.This may be the result of the different cadences for the three data sets.The highest regions of the flare energies of Kepler,K2 and TESS are 32–32.5,32–32.5 and31–31.5 erg in Log format,respectively.A linear relationship between flare duration and energy emerges from our analysis.The ratio of flare duration to total observational time is approximately 0.2%–0.3%for the Kepler,K2 and TESS surveys.The occurrence rate of a star with a flare event increases from the M0 to M4 subtypes.We also determined the spatial distribution of the flare rate of M stars in the Milky Way.It seems that the flare rate decreases as the vertical height increases.The power index of the flare energies is in the region of 1.53–2.32,which is similar to previous result for solar type star(2.0).Further,we examined the relationship between the flare amplitude and chromospheric intensity.The flare activity increases rapidly with the increase in the HαEW at the lower values(less approximately 2?)and it increases slowly at the higher values.
基金Science Foundation of Shanghai MunicipalCommission of Education(99QF5 5 ) Oneof us(S.Gu) also acknowledged the fi-nancial support of National Natural Sci-ence Foundation of China(No.197740 40 )
文摘With the use of variational method of Pekar type, this paper studied the energy levels of magnetopolaron in quantum wire with strong electron phonon interaction. The magnetopolaron binding energy in the ground state and in the excited state, as well as the resonance frequency of magnetopolaron were calculated. Their dependence on the cyclotron frequency and the confinement strength of quantum wire was depicted. The limiting case of bulk type and strict two dimensional type was discussed.
基金sponsored by the National Natural Science Foundation of China under Grant Nos.49975014,40275018,and 40333025
文摘A limited-area primitive equation model is used to study the role of the β-effect and a uniform current on tropical cyclone (TC) intensity.It is found that TC intensity is reduced in a non-quiescent environment compared with the case of no uniform current.On an f-plane,the rate of intensification of a tropical cyclone is larger than that of the uniform flow.A TC on a β-plane intensifies slower than one on an f-plane.The main physical characteristic that distinguishes the experiments is the asymmetric thermodynamic (including convective) and dynamic structures present when either a uniform flow or β-effect is introduced.But a fairly symmetric TC structure is simulated on an f-plane.The magnitude of the warm core and the associated subsidence are found to be responsible for such simulated intensity changes.On an f-plane,the convection tends to be symmetric,which results in strong upper-level convergence near the center and hence strong forced subsidence and a very warm core.On the other hand,horizontal advection of temperature cancels part of the adiabatic heating and results in less warming of the core,and hence the TC is not as intense.This advective process is due to the tilt of the vortex as a result of the β-effect.A similar situation occurs in the presence of a uniform flow.Thus,the asymmetric horizontal advection of temperature plays an important role in the temperature distribution.Dynamically,the asymmetric angular momentum (AM) flux is very small on an f-plane throughout the troposphere.However,the total AM exports at the upper levels for a TC either on aβ-plane or with a uniform flow environment are larger because of an increase of the asymmetric as well as symmetric AM export on the plane at radii >450 km,and hence there is a lesser intensification.
文摘Aimed at the difficulty in finding an efficient method to depress and recognize chaff in both time and frequency domain,this paper tries to recognize chaff and target such as warship in polarization domain under the theoretical analysis of the polarization scattering cross section of chaff.In order to find target more exactly,non-linear polarization transformation and polarization smoothness are applied to process the polarization information of chaff and ship target.The resulting recognition is proved to be effective by simulation.
文摘The method of empirical mode decomposition(EMD) was used for the signal processing and featureing of acoustic target of battle field. According to the signal's characteristics of different targets, some feature vectors in token of the target properties were constructed and abstracted. In the basis of feature abstracting and statistic analysis for large amount of sample signal of the targets, using the maximum subjection classification method based on the fuzzy synthesis judgment, the three typical acoustic target helicopter, tank and traffic vehicle were recognized.
文摘Magnetic Barkhausen Noise (MBN) is a phenomenon of electromagnetic energy emission due to the movement of magnetic domain walls inside ferromagnetic materials when they are locally magnetized by an alternating magnetic field. According to Faraday’s law of electromagnetic induction, the noise can be received by the coil attached to the surface of the material being magnetized and the noise carries the message of the characteristics of the material such as stresses, hardness, phase content, etc. Based on the characteristic of the noise, research about the relationship between the welding stresses in the welding assembly and the noise, the fatigue damage of the plate structure and the noise, and the influence of heat treatment and the variation of phase content to the noise are carried out in this paper.
文摘The compositions Ce0.8-xSm0.2O2-δ(X=0, 0.02, 0.04, 0.06) were prepared through the sol–gel route. The effect of Pr addition on the crystal structure, densification and thermal expansion of Ce0.8Sm0.2O2-δ was studied. The phase identification and morphology was studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). X-ray diffraction analysis showed that all the samples exhibit a fluorite structure. The lattice parameters? were determined by X-ray powder diffraction. Lattice parameters and volume of the unit cell increases with Pr doping. Density of the all samples is more than 90% of theoretical density. The thermal expansion was measured using dilatometric technique in the temperature range 30–1000°C. It was observed that the thermal expansion increased linearly with increasing temperature for all the samples.
文摘The present short paper is concerned with accurate explanation as well as quantification of the so called missing dark energy of the cosmos. It was always one of the main objectives of any successful general theory of high energy particle physics and quantum cosmology to keep non-physical negative norms, the so called ghosts completely out of that theory. The present work takes the completely contrary view by admitting these supposedly spurious states as part of the physical Hilbert space. It is further shown that rethinking the ghost free condition with the two critical spacetime dimensions D<sub>1</sub> = 26 and D<sub>2</sub> = 25 together with the corresponding intercept a<sub>1</sub> = 1 and a<sub>2</sub> ≤ 1 respectively and in addition imposing, as in Gross et al. heterotic superstrings, an overall 496 dimensional exceptional Lie symmetry group, then one will discover that there are two distinct types of energy. The first is positive norm ordinary energy connected to the zero set quantum particles which is very close to the measured ordinary energy density of the cosmos, namely E(O) = mc<sup>2</sup>/22. The second is negative norm (i.e. ghost) energy connected to the empty set quantum wave and is equal to the conjectured dark energy density of the cosmos E(D) = mc<sup>2</sup> (21/22) presumed to be behind the observed accelerated cosmic expansion. That way we were able to not only explain the physics of dark energy without adding any new concepts or novel additional ingredients but also we were able to compute the dark energy density accurately and in full agreement with measurements and observations.
基金supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan
文摘The collision dynamics and fragmentation process of molecule by highly charged ionimpact for single electron capture processes at the low energies below 1 keV/u were studied. Thecollision energy dependence of the recoil momentum was obtained experimentally and compared itwith those calculated by a theoretical model using a deflection function with polarization potential.A fairly good agreement between the measured and calculated results was reached. This suggeststhat the polarization potential plays a crucial role in the low-energy region.
文摘The redshift and the blueshift of spectral lines in gravitational fields of photon stars are studied when the observing and emitting points of the spectral lines locate at different positions. And the motion of mass-points is also studied. The studies show that the redshift and the blueshift of spectral lines in gravitational fields of photon stars can be arbitrarily positive, and the motion of mass-points in gravitational fields of photon stars can be used to determine the mass of photon stars.
文摘A photon avalanche phenomenon was observed in Er3+ and Li+codoped ZnO nanocrystals at room temperature under excitation around 976 nm.When the excitation power was over 120 mW/mm2,we found that the upconversion of red emission was generated by a four-photon absorption process and might be caused by intense interaction between neighboring Er3+ ions:4F7/2+4I11/2→ 24F9/2.When the excitation power was over the threshold of 240 mW/mm2,the green emission avalanche upconversion was generated through an excited-state absorption process:4F9/2+photon → 2H9/2.The study extends the knowledge of this ion to a wider range of upconversion application.
文摘Considering the interaction between the electromagnetic field and matter field, a concise method is used to calculate the ground-state energy of the interacting system. With the assumption of squeezed-like state, a new vacuum state is obtained for the inte racting system. The energy of the new vacuum state is obviously lower than that of unperturbed vacu um state. Based on the new vacuum state, the correction to the Casimir force is obtained. The r esult shows that the contribution of the interaction is a repulsive one and the Casimir effect is attributed to both electromagnetic field and matter field. On the basis of the obtained results, th e recent experimental data can be explained reasonably.
文摘The radiation dose received by patients undergoing chest radiography was included. 200 patients who attended these investigations in 10 hospitals in Iran were randomly selected from all ages groups and both female and male. Critically ill patients were excluded.This paper presents the work, which was implemented on 200 patients and evaluated using the entrance skin dose (ESD) in the posterior anterior (PA) chest projection measured directly at the center of the X-ray field. In addition, the machine room, and dark room parameters, as well as work practices and repeat rates were studied. The quality control (QC) parameters and the ESD before and after QC were evaluated utilizing an anthropomorphic phantom to define the optimal exposure condition at all hospitals. This research shows that after using the QC parameters and after optimization of the exposure conditions, the ESD was decreased by 42% on average. Also the quality of the radiographs generally increased. The reported method is easily implemented in any clinical situation where optimization of chest radiography is needed.
基金supported by NASA grant NNX14-AF77Gsupported by a NASA ADAP grant
文摘We analyze the most powerful X-ray outbursts from neutron stars in eleven Magellanic high-mass X-ray binaries and three pulsating ultraluminous X-ray sources. Most of the outbursts rise to L_(max) which is about the level of the Eddington luminosity, while the remaining more powerful outbursts also appear to recognize that limit when their emissions are assumed to be anisotropic and beamed toward our direction. We use the measurements of pulsar spin periods P_S and their derivatives P_S to calculate the X-ray luminosities L_p in their faintest accreting("propeller-line") states. In five cases with unknown P_S, we use the lowest observed X-ray luminosities, which only adds to the heterogeneity of the sample. Then we calculate the ratios L_p/L_(max) and we obtain an outstanding confluence of theory and observations from which we conclude that work done on both fronts is accurate and the results are trustworthy: sources known to reside on the lowest Magellanic propeller line are all located on/near that line, whereas other sources jump higher and reach higher-lying propeller lines. These jumps can be interpreted in only one way, higher-lying pulsars have stronger surface magnetic fields in agreement with previous empirical results in whichP_S and L_p values were not used.
文摘PB Phase Coherent States are very important quantum states in quantum optics. In order to investigate the amplitude-Nth-power squeezing of PB Phase Coherent States, we introduce the algebraic properties of the PB phase operator and the PB Phase Coherent States which are constructed by PB phase theory. We applied amplitude-Nth-power squeezing theory to define the Amplitude-Nth-Power Squeezing of PB Phase Coherent States and investigate the characteristic of the amplitude-Nth-power squeezing of PB Phase Coherent States. We obtained surprising results, in that the results were different from the other quantum states. As for |Z〉(PB Phase Coherent State), the results show that when Z is a real number there only exists amplitude-Nth-power squeezing of component; when Z is a complex number, there exists amplitude-Nth-power squeezing of component and component; when Z is a pure imaginary number, if N is odd, then there does not exist amplitude-Nth-power squeezing of component, but there exists amplitude-Nth-power squeezing of component and if N is even, then there exists amplitude-Nth-power squeezing of component, but there does not exist amplitude-Nth-power squeezing of component.
基金Supported by Doe through Science Engineering Alliance under the grant No.DE-FG05-94ER25229The numerical calculations were performed on the CRY supercomputer provided by NCSA at UIUC.
文摘Taking into account correlations in a layered two-dimensional(2D)Fermi liquid,aCoulomb-type interaction induces pairing if particle-hole excitations are taken into account.The quasi-particle pairing force is analogous to the resonating valence bond(RVB)of elec-trons in a hydrogen or positronium molecule-like structure.It is turned out that scatteringdiagrams from this model allow to evaluate the vertex function Γ.T<sub>c</sub> is hence calculated byusing the pole condition Γ<sup>-1</sup>=0.It has been found out that T<sub>c</sub> can reach quite high values andgives rise to the bell shape,and is related to the particle density,interlayer distance,dielec-tric constant and band mass.PACS numbers:74.65.+n,71.45.Gm.,74.70.Jm.,71.45.Lr.
基金Supported by the Natural Science Research Foundation of Jiangsu Higher-Learning Insti-tution (No.04jkb510057).
文摘The encoding/decoding scheme based on Fiber Bragg Grating (FBG) for Optical Code Division Multiple Access (OCDMA) system is analyzed and the whole process from transmitting end to receiving end is researched in detail. The mathematical mode including signal transmission, summing, receiving and recovering are established respectively. One of the main sources of Bit Error Rate (BER) of OCDMA system based on FBGs is the unevenness of signal power spectrum, which leads to the chip powers unequal with each other. The Signal to Interfere Ratio (SIR) and BER performance of the system are studied and simulated at the case with uneven distribution of chips' powers.
文摘Based on three typical mechanisms (second-order, third-order and competitive mechanisms) for the curing reactions of the epoxy resins with amines, a pair of the kinetic equations (for primary and secondary aminations) was presented to explain the uniformity and relationship among the three different kinetic mechanisms of the reactions. The presented macro-equations were deduced from the kinetic micro-equations by the statistics method. And the constitutive equations were verified by experimental data at different reaction times and temperatures (95°C, 60°C and 39°C), taking diglycidyl ether of bisphenol A (DGEBA) /ethyleneamine (EA) as a model.