The dispersion properties in the short wavelength region of total internal reflective photonic crystal fiber(TIRPCF) in Compton scattering have been studied by using the model of the equivalent twin waveguide soliton ...The dispersion properties in the short wavelength region of total internal reflective photonic crystal fiber(TIRPCF) in Compton scattering have been studied by using the model of the equivalent twin waveguide soliton coupling, dispersion management solitons and effective refractive index. It is shown that the positive dispersion of the cladding waveguide of TIRPCF and the negative dispersion of its core waveguide are quickly increased by the square of the collision non-elastic composition between the electron and photons, and they are lessened by the increase of the electron absorption photon number. Under the one-photon nonlinear Compton scattering, the method of the compensated probing laser diffraction by the phase hole induced by the stationary pumping laser in the cladding waveguide enables the average dispersion value of TIRPCF to be close to zero, and the zero dispersion point quickly shifts to the short wavelength region.展开更多
After considering Kerr nonlinear effect, group velocity dispersion of host and gain distribution of active particle in laser amplifying medium, a basic equation describing propagation of the coupling optical pulse und...After considering Kerr nonlinear effect, group velocity dispersion of host and gain distribution of active particle in laser amplifying medium, a basic equation describing propagation of the coupling optical pulse under the multi-photon nonlinear Compton scattering in the laser amplifying medium has been deduced. Besides, the profile and power spectrum of a picosecond-level super-Gaussian coupling pulse in the laser amplifying medium have been discussed when its central frequency coincides with the gain peak frequency of the laser amplifying medium.展开更多
The statistical properties of a homogeneously broadened ring laser with an injected signal are investigated and the normalized two-mode intensity auto- and cross-correlation functions are calculated by a full saturati...The statistical properties of a homogeneously broadened ring laser with an injected signal are investigated and the normalized two-mode intensity auto- and cross-correlation functions are calculated by a full saturation laser theory with backscattering. The theoretical predictions are in good agreement with the experimental measurements.Further investigation reveals that the backscattering can reduce the fluctuations in the system while the full saturation effect plays a major role when the laser is operated above threshold. It is also quite important to notice that the injected signal can drive the weak mode from incoherent light to coherent light.展开更多
In this paper we apply the assumption of our recent work in noncommutative scalar models to the noncommutative U（1） gauge theories. This assumption is that the noneommutative effects start to be visible continuously...In this paper we apply the assumption of our recent work in noncommutative scalar models to the noncommutative U（1） gauge theories. This assumption is that the noneommutative effects start to be visible continuously from a scale ANC and that below this scale the theory is a commutative one. Based on this assumption and using background field method and loop calculations, an effective action is derived for noncommutative U（1） gauge theory. It will be shown that the corresponding low energy effective theory is asymptotically free and that under this condition the noncommutative quadratic IR divergences will not appear. The effective theory contains higher dimensional terms, which become more important at high energies. These terms predict an elastic photon-photon scattering due to the noncommutativity of space. The coefficients of these higher dimensional terms also satisfy a positivity constraint indicating that in this theory the related diseases of superluminal signal propagating and bad analytic properties of S-matrix do not exist. In the last section, we will apply our method to the noncommutative extra dimension theories.展开更多
Urban aerosols have a large effect on the deterioration of air quality and the degradation of atmospheric visibility.Characterization of the chemical composition of PM 2.5 and in situ measurements of the optical prope...Urban aerosols have a large effect on the deterioration of air quality and the degradation of atmospheric visibility.Characterization of the chemical composition of PM 2.5 and in situ measurements of the optical properties of aerosols were conducted in July 2008 at an urban site in Guangzhou,Southern China.The mean PM 2.5 concentration for the entire period was 53.7±23.2 μg m 3.The mean PM 2.5 concentration (82.7±25.4 μg m 3) on hazy days was roughly two times higher than that on clear days (38.8±8.7 μg m 3).The total water-soluble ion species and the total average carbon accounted for 47.9%±4.3% and 35.2%±4.5%,respectively,of the major components of PM 2.5.The increase of secondary and carbonaceous aerosols,in particular ammonium sulfate,played an important role in the formation of haze pollution.The mean absorption and scattering coefficients and the single scattering albedo over the whole period were 53±20 M m 1,226±111 M m 1,and 0.80±0.04,respectively.PM 2.5 had a high linear correlation with the aerosol extinction coefficient,elemental carbon (EC) was correlated with aerosol absorption,and organic carbon (OC) and SO 4 2 were tightly linked to aerosol scattering.展开更多
TiO2 nanocrystalline porous films consisting of binary particles mixture (mean diameters of 12 and 100 nm) are capable of increasing the light absorption due to the possession of large specific surface area and light ...TiO2 nanocrystalline porous films consisting of binary particles mixture (mean diameters of 12 and 100 nm) are capable of increasing the light absorption due to the possession of large specific surface area and light scattering property. The simultaneous reduction of the film thickness leads to a decrease of the recombination loss during electron transport and an increase of the photocurrent efficiency.展开更多
Development of highly efficient photocatalysts has emerged as a research hotspot because of their crucial role in affecting the conversion efficiency of solar energy for applications in resource exploitation and envir...Development of highly efficient photocatalysts has emerged as a research hotspot because of their crucial role in affecting the conversion efficiency of solar energy for applications in resource exploitation and environmental purification.The photocatalytic performance of the photocatalysts basically depends on the behaviors of light absorption,charge generation and separation,surface property and structural stability.Owing to its unique advantages(high surface area,tunable porosity,modifiable surface),porous silica provides an interesting platform to construct well-defined nanostructures such as core-shell,yolk-shell and other specific structures which effectively improved one or more of the above behaviors for photocatalysis.Typically,the structure with hollow morphology favors the light scattering and enlargement of surface area,while coating or binding with silica can modify the surface property of a photocatalyst to enhance the surface adsorption of reactants and physicochemical stability of catalysts.This review discusses the recent advances in the design,synthesis,formation mechanism of well-defined silica-based nanostructures,and the achievements of desired physicochemical properties for regulating the photocatalytic performance.展开更多
Measurement of optical properties of skin is an expanding and growing field of research.Recent studies have shown that the biological tissue,especially skin,changes the polarization state of the incident light.Using t...Measurement of optical properties of skin is an expanding and growing field of research.Recent studies have shown that the biological tissue,especially skin,changes the polarization state of the incident light.Using this property will enable the study of abnormalities and diseases that alter not only the light intensity but also its polarization state.In this paper we report an experimental study for measuring changes of polarization state of the light scattered from a phantom similar to a sample model of scattering skin.Using the notation of Stokes vector for the polarized light and Mueller matrix for the sample with its polarization properties,we have shown that some elements of the matrix were particularly sensitive to the changes of the polarization-altering physical properties of the scatterers within the phantom.展开更多
The structural,vibrational,and magnetic properties of well prepared Bi 1 x Y x FeO 3(x=0-0.1) powders are investigated by combining the X-ray diffraction,Raman scattering,differential scanning calorimetry,and magnetom...The structural,vibrational,and magnetic properties of well prepared Bi 1 x Y x FeO 3(x=0-0.1) powders are investigated by combining the X-ray diffraction,Raman scattering,differential scanning calorimetry,and magnetometry measurements.A structural symmetric breaking from the rhombohedral R3c to orthorhombic Pnma between x=0.07 and 0.1 is identified from the X-ray and Raman measurements,accompanying a ferroelectric-antiferroelectric phase transition.The remnant magnetization of Bi 0.9 Y 0.1 FeO 3 is about 15 times higher in magnitude compared to the pure BiFeO 3.Such a giant enhancement is suggested to result from the destruction of the spin cycloid accompanied with the structured transition.展开更多
文摘The dispersion properties in the short wavelength region of total internal reflective photonic crystal fiber(TIRPCF) in Compton scattering have been studied by using the model of the equivalent twin waveguide soliton coupling, dispersion management solitons and effective refractive index. It is shown that the positive dispersion of the cladding waveguide of TIRPCF and the negative dispersion of its core waveguide are quickly increased by the square of the collision non-elastic composition between the electron and photons, and they are lessened by the increase of the electron absorption photon number. Under the one-photon nonlinear Compton scattering, the method of the compensated probing laser diffraction by the phase hole induced by the stationary pumping laser in the cladding waveguide enables the average dispersion value of TIRPCF to be close to zero, and the zero dispersion point quickly shifts to the short wavelength region.
文摘After considering Kerr nonlinear effect, group velocity dispersion of host and gain distribution of active particle in laser amplifying medium, a basic equation describing propagation of the coupling optical pulse under the multi-photon nonlinear Compton scattering in the laser amplifying medium has been deduced. Besides, the profile and power spectrum of a picosecond-level super-Gaussian coupling pulse in the laser amplifying medium have been discussed when its central frequency coincides with the gain peak frequency of the laser amplifying medium.
文摘The statistical properties of a homogeneously broadened ring laser with an injected signal are investigated and the normalized two-mode intensity auto- and cross-correlation functions are calculated by a full saturation laser theory with backscattering. The theoretical predictions are in good agreement with the experimental measurements.Further investigation reveals that the backscattering can reduce the fluctuations in the system while the full saturation effect plays a major role when the laser is operated above threshold. It is also quite important to notice that the injected signal can drive the weak mode from incoherent light to coherent light.
文摘In this paper we apply the assumption of our recent work in noncommutative scalar models to the noncommutative U（1） gauge theories. This assumption is that the noneommutative effects start to be visible continuously from a scale ANC and that below this scale the theory is a commutative one. Based on this assumption and using background field method and loop calculations, an effective action is derived for noncommutative U（1） gauge theory. It will be shown that the corresponding low energy effective theory is asymptotically free and that under this condition the noncommutative quadratic IR divergences will not appear. The effective theory contains higher dimensional terms, which become more important at high energies. These terms predict an elastic photon-photon scattering due to the noncommutativity of space. The coefficients of these higher dimensional terms also satisfy a positivity constraint indicating that in this theory the related diseases of superluminal signal propagating and bad analytic properties of S-matrix do not exist. In the last section, we will apply our method to the noncommutative extra dimension theories.
基金supported by the Special Scientific Research Funds for Environment Protection Commonweal Section(Grant Nos.200809143and201009001)the National Basic Research Program of China(Grant No.2010CB428503)+4 种基金the National Natural Science Foundation of China(Grant No.41075096)the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.IAP09320)the Research and Development Special Fund for Public Welfare Industry(Meteorology) of the China Meteorological Administration(Grant No.GYHY201006047)the Ministry of Science and Technology of China(Grant No.2010DFA22770)the Innovation Method Fund of China(Grant No.2008IM020500)
文摘Urban aerosols have a large effect on the deterioration of air quality and the degradation of atmospheric visibility.Characterization of the chemical composition of PM 2.5 and in situ measurements of the optical properties of aerosols were conducted in July 2008 at an urban site in Guangzhou,Southern China.The mean PM 2.5 concentration for the entire period was 53.7±23.2 μg m 3.The mean PM 2.5 concentration (82.7±25.4 μg m 3) on hazy days was roughly two times higher than that on clear days (38.8±8.7 μg m 3).The total water-soluble ion species and the total average carbon accounted for 47.9%±4.3% and 35.2%±4.5%,respectively,of the major components of PM 2.5.The increase of secondary and carbonaceous aerosols,in particular ammonium sulfate,played an important role in the formation of haze pollution.The mean absorption and scattering coefficients and the single scattering albedo over the whole period were 53±20 M m 1,226±111 M m 1,and 0.80±0.04,respectively.PM 2.5 had a high linear correlation with the aerosol extinction coefficient,elemental carbon (EC) was correlated with aerosol absorption,and organic carbon (OC) and SO 4 2 were tightly linked to aerosol scattering.
基金supported by the National Research Fund for the Basic Key Project(Grant No.G2000028205)the Knowledge Innovation Foundation of the Chinese Academy of Sciences(Grant No.KGCX2-303-02).
文摘TiO2 nanocrystalline porous films consisting of binary particles mixture (mean diameters of 12 and 100 nm) are capable of increasing the light absorption due to the possession of large specific surface area and light scattering property. The simultaneous reduction of the film thickness leads to a decrease of the recombination loss during electron transport and an increase of the photocurrent efficiency.
基金supported by the National Natural Science Foundation of China(21771070 and 21571071)the Fundamental Research Funds for the Central Universities(2018KFYYXJJ120 and 2019KFYRCPY104)。
文摘Development of highly efficient photocatalysts has emerged as a research hotspot because of their crucial role in affecting the conversion efficiency of solar energy for applications in resource exploitation and environmental purification.The photocatalytic performance of the photocatalysts basically depends on the behaviors of light absorption,charge generation and separation,surface property and structural stability.Owing to its unique advantages(high surface area,tunable porosity,modifiable surface),porous silica provides an interesting platform to construct well-defined nanostructures such as core-shell,yolk-shell and other specific structures which effectively improved one or more of the above behaviors for photocatalysis.Typically,the structure with hollow morphology favors the light scattering and enlargement of surface area,while coating or binding with silica can modify the surface property of a photocatalyst to enhance the surface adsorption of reactants and physicochemical stability of catalysts.This review discusses the recent advances in the design,synthesis,formation mechanism of well-defined silica-based nanostructures,and the achievements of desired physicochemical properties for regulating the photocatalytic performance.
文摘Measurement of optical properties of skin is an expanding and growing field of research.Recent studies have shown that the biological tissue,especially skin,changes the polarization state of the incident light.Using this property will enable the study of abnormalities and diseases that alter not only the light intensity but also its polarization state.In this paper we report an experimental study for measuring changes of polarization state of the light scattered from a phantom similar to a sample model of scattering skin.Using the notation of Stokes vector for the polarized light and Mueller matrix for the sample with its polarization properties,we have shown that some elements of the matrix were particularly sensitive to the changes of the polarization-altering physical properties of the scatterers within the phantom.
基金supported by the Cultivation Fund of the Key Scientific and Technical Innovation Project,Ministry of Education of China (Grant No.708070)the National Natural Science Foundation of China (GrantNos. 10874046 and 11104081)
文摘The structural,vibrational,and magnetic properties of well prepared Bi 1 x Y x FeO 3(x=0-0.1) powders are investigated by combining the X-ray diffraction,Raman scattering,differential scanning calorimetry,and magnetometry measurements.A structural symmetric breaking from the rhombohedral R3c to orthorhombic Pnma between x=0.07 and 0.1 is identified from the X-ray and Raman measurements,accompanying a ferroelectric-antiferroelectric phase transition.The remnant magnetization of Bi 0.9 Y 0.1 FeO 3 is about 15 times higher in magnitude compared to the pure BiFeO 3.Such a giant enhancement is suggested to result from the destruction of the spin cycloid accompanied with the structured transition.
