In this paper,we calculate the resolution of a photorefractive incoherent-to-coherent optical converter on the image plane for small diffraction efficiency by taking into account the optical imaging characteristics of...In this paper,we calculate the resolution of a photorefractive incoherent-to-coherent optical converter on the image plane for small diffraction efficiency by taking into account the optical imaging characteristics of the imaging lens.For a thin grating,we obtain a high resolution,which is comparable with the experimental results.展开更多
By using a degree-day based distributed hydrological model, regimes of glacial runoff from the Koxkar glacier during 2007-2011 are simulated, and variations and characteristics of major hydrological components are dis...By using a degree-day based distributed hydrological model, regimes of glacial runoff from the Koxkar glacier during 2007-2011 are simulated, and variations and characteristics of major hydrological components are discussed. The results show that the meltwater runoff contributes 67.4%, of the proglacial discharge, out of which snowmelt, clean ice melting, buried-ice ablation and ice-cliff backwasting account for 22.4%, 21.9%, 17.9% and 5.3% of the total melt runoff, respectively. Rainfall runoff is significant in mid-latitude glacierized mountain areas like Tianshan and Karakorum. In the Koxkar glacier catchment, about 11.5% of stream water is initiated from liquid precipitation. Spatial distributions for each glacial runoff component reveal the importance of climatic gradients, local topography and morphology on glacial runoff generation, and temporal variations of these components is closely related to the annual cycle of catchment meteorology and glacier storage. Four stages are recognized in the seasonal variations of glacier storage, reflecting changes in meltwater yields, meteorological conditions and drainage systems in the annual hydrological cycle.展开更多
In marine seismic exploration,especially in deep-water and hard ocean-bottom cases,free-surface multiples are strongly developed.Compared with primary waves,the wider illumination aperture of the multiples is benefici...In marine seismic exploration,especially in deep-water and hard ocean-bottom cases,free-surface multiples are strongly developed.Compared with primary waves,the wider illumination aperture of the multiples is beneficial for high-resolution seismic imaging.In this study,by introducing a new compound source composed of primaries and free-surface multiples and by ignoring internal multiples,we derive a new linearized forward problem(free-surface-multiple prediction model)under a weak-scattering assumption(i.e.,first-order Born approximation).On the basis of the new linearized problem,we propose a joint inversion-imaging method by simultaneously using the primaries and free-surface multiples under the general framework of least square inversion.To eliminate the crosstalk artifacts introduced by the cross-correlation of multiples with different orders,we prove that the crosstalk artifacts can be gradually eliminated during the inversion if a proper step length is selected.Synthetic-andfield-data tests demonstrate the effectiveness of the proposed method.展开更多
We study the quantum nucleation in a nanometer-scale antiferromagnet placed in a magnetic field at an arbitrary angle. We consider the magnetocrystalline anisotropy with tetragonal symmetry and that with hexagonal sym...We study the quantum nucleation in a nanometer-scale antiferromagnet placed in a magnetic field at an arbitrary angle. We consider the magnetocrystalline anisotropy with tetragonal symmetry and that with hexagonal symmetry, respectively. Different structures of the tunneling barriers can be generated by the magnitude and the orientation of the magnetic field. We use the instanton method in the spin-coherent-state path-integral representation to calculate the dependence of the rate of quantum nucleation and the crossover temperature on the orientation and strength of the field for bulk solids and two-dimensional films of antiferromagnets, respectively. We find that the rate of quantum nucleation and the crossover temperature from thermal-to-quantum transitions depend on the orientation and strength of the external magnetic field distinctly, which can be tested by use of existing experimental techniques.展开更多
Education is a mental effort that an individual performs alone or in a group for the purpose of perceiving the surrounding, understanding, and putting a meaning on it. In this sense, it would be a reasonable idea that...Education is a mental effort that an individual performs alone or in a group for the purpose of perceiving the surrounding, understanding, and putting a meaning on it. In this sense, it would be a reasonable idea that an individual should benefit from art education in order to have a complete education, since art is not just creating an aesthetic object or being aware of staying against an aesthetic object. Art means that it occurs in every stage, in every action, in all attitudes and behaviors of human being realized in an aesthetic concern without thinking When the individuals having an art education in primary and secondary education start their education in a higher education program in a faculty or department other than art education, art education loses its continuity. However art education should be continuous and it is of importance in terms of its contribution to this continuity since the studies of art education for the adults out of formal education would support it. The purpose of the current study was to determine the needs of adults and also the support that would be obtained from any kind of educational activities for art education, and to propose some recommendations in this sense展开更多
The demands for high quality products are increasing in the market, so several tests are performed. These analyses are destructive, time consuming and sometimes expensive. The spectral imaging technique is an alternat...The demands for high quality products are increasing in the market, so several tests are performed. These analyses are destructive, time consuming and sometimes expensive. The spectral imaging technique is an alternative that can reduce costs and time and increase the efficiency and cost-effectiveness of these analyses. In this context, the aim of this study was to verify the spectral behavior of the tomato in function of the maturation and its potential use for non-destructive evaluation of food quality. Eighty tomatoes of the Italian group were selected in four stages of maturation (green, pink, light red and red). Images were collected in wavelengths 480 nm to 710 nm (every 10 nm). After the images were collected, the fruits were submitted to the physical-chemical analyses. The following parameters were analyzed: color, color index (CI), pH, soluble solids (SS), total titratable acidity (TTA) and ratio (SS/TTA). After characterization the mean spectrum was obtained by the extraction of the spectral characteristics. It was observed that the spectral behavior was the same for all stages of maturation. It was possible to differentiate the green tomatoes in the wavelengths from 520 nm to 560 nm and from 610 nm to 660 nm. These intervals represent the area of reflection of chlorophyll and lycopene, respectively. Near the wavelength 560 nm, the highest absorbance was recorded by ripe tomatoes due to the concentration of lycopene. It is concluded that the best wavelengths for analysis are those in which green has the highest reflectance and it is possible to apply this technique for non-destructive analysis of the maturation of tomatoes.展开更多
The effect of an applied magnetic field on an inhomogeneous superconductor is studied and the value of the upper critical magnetic field Hc3 at which superconductivity can nucleate is estimated. In addition, the autho...The effect of an applied magnetic field on an inhomogeneous superconductor is studied and the value of the upper critical magnetic field Hc3 at which superconductivity can nucleate is estimated. In addition, the authors locate the concentration of the order parameter, which depends on the inhomogeneous term a(x). Unlikely to the homogeneous case, the order parameter may concentrate in the interior of the superconducting material, due to the influence of the inhomogeneous term a(x).展开更多
An integrated and reliable phase unwrapping algorithm is proposed based on residues and blocking-lines detection, closed contour extraction and quality map ordering for the measurement of 3D shapes by Fourier-transfor...An integrated and reliable phase unwrapping algorithm is proposed based on residues and blocking-lines detection, closed contour extraction and quality map ordering for the measurement of 3D shapes by Fourier-transform profilometry (FTP). The proposed algorithm first detects the residues on the wrapped phase image, applies wavelet analysis to generate the blocking-lines that can just connect the residues of opposite polarity, then carries out the morphology operation to extract the closed contour of the shape, and finally uses the modulation intensity information and the Laplacian of Gaussian operation of the wrapped phase image as the quality map. The unwrapping process is completed from a region of high reliability to that of low reliability and the blocking-lines can prevent the phase error propagation effectively. Furthermore, by using the extracted closed contour to exclude the invalid areas from the phase unwrapping process, the algorithm becomes more efficient. The experiment shows the effec-tiveness of the new algorithm.展开更多
文摘In this paper,we calculate the resolution of a photorefractive incoherent-to-coherent optical converter on the image plane for small diffraction efficiency by taking into account the optical imaging characteristics of the imaging lens.For a thin grating,we obtain a high resolution,which is comparable with the experimental results.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences under Grant No. KZCX2-YW-GJ04National Nature Science Foundation of China (NSFC) under Grant Nos. 41130641 and 41271078
文摘By using a degree-day based distributed hydrological model, regimes of glacial runoff from the Koxkar glacier during 2007-2011 are simulated, and variations and characteristics of major hydrological components are discussed. The results show that the meltwater runoff contributes 67.4%, of the proglacial discharge, out of which snowmelt, clean ice melting, buried-ice ablation and ice-cliff backwasting account for 22.4%, 21.9%, 17.9% and 5.3% of the total melt runoff, respectively. Rainfall runoff is significant in mid-latitude glacierized mountain areas like Tianshan and Karakorum. In the Koxkar glacier catchment, about 11.5% of stream water is initiated from liquid precipitation. Spatial distributions for each glacial runoff component reveal the importance of climatic gradients, local topography and morphology on glacial runoff generation, and temporal variations of these components is closely related to the annual cycle of catchment meteorology and glacier storage. Four stages are recognized in the seasonal variations of glacier storage, reflecting changes in meltwater yields, meteorological conditions and drainage systems in the annual hydrological cycle.
基金the sponsors of the WPI group for their financial supportfinancially supported by the National Key R&D Program of China (Grant Number: 2018YFA0702503, 2019YFC0312004)+2 种基金National Natural Science Foundation of China (Grant Number: 41774126)Southern Marine Science and Engineering Guangdong Laboratory (Zhanjiang) (ZJW-2019-04)National Science and Technology Major Project of China (Grant Number: 2016ZX05024-001, 2016ZX05006-002)。
文摘In marine seismic exploration,especially in deep-water and hard ocean-bottom cases,free-surface multiples are strongly developed.Compared with primary waves,the wider illumination aperture of the multiples is beneficial for high-resolution seismic imaging.In this study,by introducing a new compound source composed of primaries and free-surface multiples and by ignoring internal multiples,we derive a new linearized forward problem(free-surface-multiple prediction model)under a weak-scattering assumption(i.e.,first-order Born approximation).On the basis of the new linearized problem,we propose a joint inversion-imaging method by simultaneously using the primaries and free-surface multiples under the general framework of least square inversion.To eliminate the crosstalk artifacts introduced by the cross-correlation of multiples with different orders,we prove that the crosstalk artifacts can be gradually eliminated during the inversion if a proper step length is selected.Synthetic-andfield-data tests demonstrate the effectiveness of the proposed method.
基金The project supported by National Natural Science Foundation of China under Grant No.90101003China's “863” Program
文摘We study the quantum nucleation in a nanometer-scale antiferromagnet placed in a magnetic field at an arbitrary angle. We consider the magnetocrystalline anisotropy with tetragonal symmetry and that with hexagonal symmetry, respectively. Different structures of the tunneling barriers can be generated by the magnitude and the orientation of the magnetic field. We use the instanton method in the spin-coherent-state path-integral representation to calculate the dependence of the rate of quantum nucleation and the crossover temperature on the orientation and strength of the field for bulk solids and two-dimensional films of antiferromagnets, respectively. We find that the rate of quantum nucleation and the crossover temperature from thermal-to-quantum transitions depend on the orientation and strength of the external magnetic field distinctly, which can be tested by use of existing experimental techniques.
文摘Education is a mental effort that an individual performs alone or in a group for the purpose of perceiving the surrounding, understanding, and putting a meaning on it. In this sense, it would be a reasonable idea that an individual should benefit from art education in order to have a complete education, since art is not just creating an aesthetic object or being aware of staying against an aesthetic object. Art means that it occurs in every stage, in every action, in all attitudes and behaviors of human being realized in an aesthetic concern without thinking When the individuals having an art education in primary and secondary education start their education in a higher education program in a faculty or department other than art education, art education loses its continuity. However art education should be continuous and it is of importance in terms of its contribution to this continuity since the studies of art education for the adults out of formal education would support it. The purpose of the current study was to determine the needs of adults and also the support that would be obtained from any kind of educational activities for art education, and to propose some recommendations in this sense
文摘The demands for high quality products are increasing in the market, so several tests are performed. These analyses are destructive, time consuming and sometimes expensive. The spectral imaging technique is an alternative that can reduce costs and time and increase the efficiency and cost-effectiveness of these analyses. In this context, the aim of this study was to verify the spectral behavior of the tomato in function of the maturation and its potential use for non-destructive evaluation of food quality. Eighty tomatoes of the Italian group were selected in four stages of maturation (green, pink, light red and red). Images were collected in wavelengths 480 nm to 710 nm (every 10 nm). After the images were collected, the fruits were submitted to the physical-chemical analyses. The following parameters were analyzed: color, color index (CI), pH, soluble solids (SS), total titratable acidity (TTA) and ratio (SS/TTA). After characterization the mean spectrum was obtained by the extraction of the spectral characteristics. It was observed that the spectral behavior was the same for all stages of maturation. It was possible to differentiate the green tomatoes in the wavelengths from 520 nm to 560 nm and from 610 nm to 660 nm. These intervals represent the area of reflection of chlorophyll and lycopene, respectively. Near the wavelength 560 nm, the highest absorbance was recorded by ripe tomatoes due to the concentration of lycopene. It is concluded that the best wavelengths for analysis are those in which green has the highest reflectance and it is possible to apply this technique for non-destructive analysis of the maturation of tomatoes.
基金Project supported by the National Natural Science Foundation of China (No.10071067) the Excellent Young Teachers Program of the Ministry of Education of China, the Jiangsu Provincial Natural Science Foundation of China and the Combinatorial and Computa
文摘The effect of an applied magnetic field on an inhomogeneous superconductor is studied and the value of the upper critical magnetic field Hc3 at which superconductivity can nucleate is estimated. In addition, the authors locate the concentration of the order parameter, which depends on the inhomogeneous term a(x). Unlikely to the homogeneous case, the order parameter may concentrate in the interior of the superconducting material, due to the influence of the inhomogeneous term a(x).
基金Project (Nos. 2007AA04Z1A5 and 2007AA01Z311) supported by the Hi-Tech Research and Development Program (863) of China
文摘An integrated and reliable phase unwrapping algorithm is proposed based on residues and blocking-lines detection, closed contour extraction and quality map ordering for the measurement of 3D shapes by Fourier-transform profilometry (FTP). The proposed algorithm first detects the residues on the wrapped phase image, applies wavelet analysis to generate the blocking-lines that can just connect the residues of opposite polarity, then carries out the morphology operation to extract the closed contour of the shape, and finally uses the modulation intensity information and the Laplacian of Gaussian operation of the wrapped phase image as the quality map. The unwrapping process is completed from a region of high reliability to that of low reliability and the blocking-lines can prevent the phase error propagation effectively. Furthermore, by using the extracted closed contour to exclude the invalid areas from the phase unwrapping process, the algorithm becomes more efficient. The experiment shows the effec-tiveness of the new algorithm.