Two kinds of subwavelength hole arrays in metallic films are designed to verify the import, ant role of the periodicity in enhanced transmission of light. The measured optical spectra show that the quasiperiodic hole ...Two kinds of subwavelength hole arrays in metallic films are designed to verify the import, ant role of the periodicity in enhanced transmission of light. The measured optical spectra show that the quasiperiodic hole arrays exhibit an enhanced transmission peak centred at 707nm with a transmission intensity of about 20%, while no plasmon resonance peak is found for the amorphous hole arrays. When the hole diameter decreases in the quasiperiodic structure, the position of the transmission peak shifts slightly, and the transmittance drops, These phenomena indicate the important role of the long-range structural order （particularly the periodicity） in assisting the coupling of incident light wave with the surface plasmon modes of the metallic structures.展开更多
This study aims to propose an empirical prediction model of hydraulic aperture of 2D rough fractures through numerical simulations by considering the influences of fracture length,average mechanical aperture,minimum m...This study aims to propose an empirical prediction model of hydraulic aperture of 2D rough fractures through numerical simulations by considering the influences of fracture length,average mechanical aperture,minimum mechanical aperture,joint roughness coefficient(JRC)and hydraulic gradient.We generate 600 numerical models using successive random additions(SRA)algorithm and for each model,seven hydraulic gradients spanning from 2.5×10^(-7)to 1 are considered to fully cover both linear and nonlinear flow regimes.As a result,a total of 4200 fluid flow cases are simulated,which can provide sufficient data for the prediction of hydraulic aperture.The results show that as the ratio of average mechanical aperture to fracture length increases from 0.01 to 0.2,the hydraulic aperture increases following logarithm functions.As the hydraulic gradient increases from 2.5×10^(-7)to 1,the hydraulic aperture decreases following logarithm functions.When a relatively low hydraulic gradient(i.e.,5×10^(-7))is applied between the inlet and the outlet boundaries,the streamlines are of parallel distribution within the fractures.However,when a relatively large hydraulic gradient(i.e.,0.5)is applied between the inlet and the outlet boundaries,the streamlines are disturbed and a number of eddies are formed.The hydraulic aperture predicted using the proposed empirical functions agree well with the calculated results and is more reliable than those available in the preceding literature.In practice,the hydraulic aperture can be calculated as a first-order estimation using the proposed prediction model when the associated parameters are given.展开更多
Deuterated potassium dihydrogen phosphate damage performance at 351 nm is studied on a large-aperture laser system. Bulk and rear-surface damage are initiated under the 3ω fluences of 6.T J/cm2 and 33/cm2, and show d...Deuterated potassium dihydrogen phosphate damage performance at 351 nm is studied on a large-aperture laser system. Bulk and rear-surface damage are initiated under the 3ω fluences of 6.T J/cm2 and 33/cm2, and show different growth characteristics under multiple laser irradiations with the fluence of 6 J/cm2. The size and number of bulk damage keep unchanged once initiated. However, surface damage size also does not grow, while surface damage number increases linearly with laser shots. Different damage thresholds and growth behaviors suggest different formations of bulk and surface damage precursors. The cause of surface damage is supposed to be near-surface absorbing particles buried under the sol-gel coating.展开更多
Due to the low spatial resolution of sea surface temperature(T_S)retrieval by real aperture microwave radiometers,in this study,an iterative retrieval method that minimizes the differences between brightness temperatu...Due to the low spatial resolution of sea surface temperature(T_S)retrieval by real aperture microwave radiometers,in this study,an iterative retrieval method that minimizes the differences between brightness temperature(T_B)measured and modeled was used to retrieve sea surface temperature with a one-dimensional synthetic aperture microwave radiometer,temporarily named 1 D-SAMR.Regarding the configuration of the radiometer,an angular resolution of 0.43°was reached by theoretical calculation.Experiments on sea surface temperature retrieval were carried out with ideal parameters;the results show that the main factors affecting the retrieval accuracy of sea surface temperature are the accuracy of radiometer calibration and the precision of auxiliary geophysical parameters.In the case of no auxiliary parameter errors,the greatest error in retrieved sea surface temperature is obtained at low T_S scene(i.e.,0.7106 K for the incidence angle of 35°under the radiometer calibration accuracy of0.5 K).While errors on auxiliary parameters are assumed to follow a Gaussian distribution,the greatest error on retrieved sea surface temperature was 1.3305 K at an incidence angle of 65°in poorly known sea surface wind speed(W)(the error on W of 1.0 m/s)over high W scene,for the radiometer calibration accuracy of 0.5 K.展开更多
We investigate optical properties of a bowtie-shaped aperture using the finite difference time domain method to optimize its geometric parameters for specific incident lights. The influence of the parameters on local ...We investigate optical properties of a bowtie-shaped aperture using the finite difference time domain method to optimize its geometric parameters for specific incident lights. The influence of the parameters on local field enhancement and resonant wavelength in the visible frequency range is numerically analysed. It is found that the major resonance of the spectrum is exponentially depended on the bowtie angle but independent of the whole aperture size. The simulation also demonstrates that increasing the aperture size raises the local field intensity on the exit plane due to an enlarged interaction area between the light and the metal medium. And the near-field spot size is closely related to the gap. Based on these results, the design rules of the bowtie structure can be optimized for specific wavelengths excited.展开更多
This study aimed to investigate the mechanism of mineral spontaneous combustion in an open pit. On the study of coal and mineral mixture in open pit mines, as well as through the specifc surface area and Search Engine...This study aimed to investigate the mechanism of mineral spontaneous combustion in an open pit. On the study of coal and mineral mixture in open pit mines, as well as through the specifc surface area and Search Engine Marketing (SEM) experiments, the specifc surface area and aperture characteristics of distribution of open pit coal sample and pit mineral mixture samples were analyzed. Thermal analysis experiments were used to divide the oxidation process was divided into three stages, and the thermal behavior characteristics of experimental samples were characterized. On the basis of the stage division, we explored the transfer law of the key active functional groups of the experimental samples. The apparent activation energy calculation of the key active groups, performed by combining the Achar diferential method with the Coats–Redfern integral method, microstructural and oxidation kinetic properties were revealed. The resulted showed that the mixed sample had high ash, the fxed carbon content was reduced, the specifc surface area was far lower than the raw coal, the large aperture distribution was slightly higher than the medium hole, the micropore was exceptionally low, the gas adsorption capacity was weaker than the raw coal, the pit coal sample had the exceedingly more active functional groups, easy to react with oxygen, more likely to occur naturally, and its harm was relatively large. The mixed sample contained the highest C–O–C functional group absorbance. The functional groups were mainly infuenced by the self-OH content, alkyl side chain, and fatty hydrocarbon in the sample. The main functional groups of the four-like mixture had the highest apparent activation energy, and the two reactions were higher in the low-temperature oxidation phase.展开更多
The nonlinear flow properties of Newtonian fluids through crossed fractures are estimated by considering the influences of length,aperture,and surface roughness of fractures.A total of 252 computational runs are perfo...The nonlinear flow properties of Newtonian fluids through crossed fractures are estimated by considering the influences of length,aperture,and surface roughness of fractures.A total of 252 computational runs are performed by creating 36 computational domains,in which the Navier-Stokes equations are solved.The results show that the nonlinear relationship between flow rate and hydraulic gradient follows Forchheimer’s law–based equation.When the hydraulic gradient is small(i.e.,10^(−6)),the streamlines are parallel to the fracture walls,indicating a linear streamline distribution.When the hydraulic gradient is large(i.e.,10^(0)),the streamlines are disturbed by a certain number of eddies,indicating a nonlinear streamline distribution.The patterns of eddy distributions depend on the length,aperture,and surface roughness of fractures.With the increment of hydraulic gradient from 10^(−6) to 10^(0),the ratio of flow rate to hydraulic gradient holds constants and then decreases slightly and finally decreases robustly.The fluid flow experiences a linear flow regime,a weakly nonlinear regime,and a strongly nonlinear regime,respectively.The critical hydraulic gradient ranges from 3.27×10^(−5) to 5.82×10^(−2) when fracture length=20–100mmandmechanical aperture=1–5mm.The joint roughness coefficient plays a negligible role in the variations in critical hydraulic gradient compared with fracture length and/or mechanical aperture.The critical hydraulic gradient decreases with increasing mechanical aperture,following power-law relationships.The parameters in the functions are associated with fracture length.展开更多
Polarization-stable 980 nm oxide-confined vertical-cavity surface-emitting lasers with 3 μm diamond-shaped aper- ture are fabricated by comprehensively utilizing the anisotropic properties of wet etching and wet nitr...Polarization-stable 980 nm oxide-confined vertical-cavity surface-emitting lasers with 3 μm diamond-shaped aper- ture are fabricated by comprehensively utilizing the anisotropic properties of wet etching and wet nitrogen oxida- tion of Ⅲ-Ⅴ semiconductor materials. Polarization-stable operation along the major axis of the diamond-shaped oxide aperture with 11 dB orthogonal polarization suppression ratio is achieved in a temperature range of 15-55℃ from the threshold to 4 mA.展开更多
文摘Two kinds of subwavelength hole arrays in metallic films are designed to verify the import, ant role of the periodicity in enhanced transmission of light. The measured optical spectra show that the quasiperiodic hole arrays exhibit an enhanced transmission peak centred at 707nm with a transmission intensity of about 20%, while no plasmon resonance peak is found for the amorphous hole arrays. When the hole diameter decreases in the quasiperiodic structure, the position of the transmission peak shifts slightly, and the transmittance drops, These phenomena indicate the important role of the long-range structural order （particularly the periodicity） in assisting the coupling of incident light wave with the surface plasmon modes of the metallic structures.
基金funded by National Key R&D Program of China(No.2022YFE0128300)National Natural Science Foundation of China(Grant Nos.52379114 and 52379113)+2 种基金Natural Science Foundation of Jiangsu Province,China(No.BK20211584)the Assistance Program for Future Outstanding Talents of the China University of Mining and Technology(No.2023WLKXJ187)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX23_2746).
文摘This study aims to propose an empirical prediction model of hydraulic aperture of 2D rough fractures through numerical simulations by considering the influences of fracture length,average mechanical aperture,minimum mechanical aperture,joint roughness coefficient(JRC)and hydraulic gradient.We generate 600 numerical models using successive random additions(SRA)algorithm and for each model,seven hydraulic gradients spanning from 2.5×10^(-7)to 1 are considered to fully cover both linear and nonlinear flow regimes.As a result,a total of 4200 fluid flow cases are simulated,which can provide sufficient data for the prediction of hydraulic aperture.The results show that as the ratio of average mechanical aperture to fracture length increases from 0.01 to 0.2,the hydraulic aperture increases following logarithm functions.As the hydraulic gradient increases from 2.5×10^(-7)to 1,the hydraulic aperture decreases following logarithm functions.When a relatively low hydraulic gradient(i.e.,5×10^(-7))is applied between the inlet and the outlet boundaries,the streamlines are of parallel distribution within the fractures.However,when a relatively large hydraulic gradient(i.e.,0.5)is applied between the inlet and the outlet boundaries,the streamlines are disturbed and a number of eddies are formed.The hydraulic aperture predicted using the proposed empirical functions agree well with the calculated results and is more reliable than those available in the preceding literature.In practice,the hydraulic aperture can be calculated as a first-order estimation using the proposed prediction model when the associated parameters are given.
基金Supported by the National Natural Science Foundation of China under Grant No 61505187
文摘Deuterated potassium dihydrogen phosphate damage performance at 351 nm is studied on a large-aperture laser system. Bulk and rear-surface damage are initiated under the 3ω fluences of 6.T J/cm2 and 33/cm2, and show different growth characteristics under multiple laser irradiations with the fluence of 6 J/cm2. The size and number of bulk damage keep unchanged once initiated. However, surface damage size also does not grow, while surface damage number increases linearly with laser shots. Different damage thresholds and growth behaviors suggest different formations of bulk and surface damage precursors. The cause of surface damage is supposed to be near-surface absorbing particles buried under the sol-gel coating.
基金The National Natural Science Foundation of China under contract Nos 41475019,41575028,41705007,41605016,and 41505016。
文摘Due to the low spatial resolution of sea surface temperature(T_S)retrieval by real aperture microwave radiometers,in this study,an iterative retrieval method that minimizes the differences between brightness temperature(T_B)measured and modeled was used to retrieve sea surface temperature with a one-dimensional synthetic aperture microwave radiometer,temporarily named 1 D-SAMR.Regarding the configuration of the radiometer,an angular resolution of 0.43°was reached by theoretical calculation.Experiments on sea surface temperature retrieval were carried out with ideal parameters;the results show that the main factors affecting the retrieval accuracy of sea surface temperature are the accuracy of radiometer calibration and the precision of auxiliary geophysical parameters.In the case of no auxiliary parameter errors,the greatest error in retrieved sea surface temperature is obtained at low T_S scene(i.e.,0.7106 K for the incidence angle of 35°under the radiometer calibration accuracy of0.5 K).While errors on auxiliary parameters are assumed to follow a Gaussian distribution,the greatest error on retrieved sea surface temperature was 1.3305 K at an incidence angle of 65°in poorly known sea surface wind speed(W)(the error on W of 1.0 m/s)over high W scene,for the radiometer calibration accuracy of 0.5 K.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10975012)
文摘We investigate optical properties of a bowtie-shaped aperture using the finite difference time domain method to optimize its geometric parameters for specific incident lights. The influence of the parameters on local field enhancement and resonant wavelength in the visible frequency range is numerically analysed. It is found that the major resonance of the spectrum is exponentially depended on the bowtie angle but independent of the whole aperture size. The simulation also demonstrates that increasing the aperture size raises the local field intensity on the exit plane due to an enlarged interaction area between the light and the metal medium. And the near-field spot size is closely related to the gap. Based on these results, the design rules of the bowtie structure can be optimized for specific wavelengths excited.
基金Financial support for this study was kindly provided by the National Natural Science Foundation Project of China(5217-4202)Young Elite Scientists Sponsorship Program of China Association for Science,and Technology(2021QNRC001).
文摘This study aimed to investigate the mechanism of mineral spontaneous combustion in an open pit. On the study of coal and mineral mixture in open pit mines, as well as through the specifc surface area and Search Engine Marketing (SEM) experiments, the specifc surface area and aperture characteristics of distribution of open pit coal sample and pit mineral mixture samples were analyzed. Thermal analysis experiments were used to divide the oxidation process was divided into three stages, and the thermal behavior characteristics of experimental samples were characterized. On the basis of the stage division, we explored the transfer law of the key active functional groups of the experimental samples. The apparent activation energy calculation of the key active groups, performed by combining the Achar diferential method with the Coats–Redfern integral method, microstructural and oxidation kinetic properties were revealed. The resulted showed that the mixed sample had high ash, the fxed carbon content was reduced, the specifc surface area was far lower than the raw coal, the large aperture distribution was slightly higher than the medium hole, the micropore was exceptionally low, the gas adsorption capacity was weaker than the raw coal, the pit coal sample had the exceedingly more active functional groups, easy to react with oxygen, more likely to occur naturally, and its harm was relatively large. The mixed sample contained the highest C–O–C functional group absorbance. The functional groups were mainly infuenced by the self-OH content, alkyl side chain, and fatty hydrocarbon in the sample. The main functional groups of the four-like mixture had the highest apparent activation energy, and the two reactions were higher in the low-temperature oxidation phase.
基金funded by National Key Research and Development Program of China,China (Grant No.2020YFA0711800)Natural Science Foundation of China,China (Grant Nos.51979272 and 51879150)+1 种基金Natural Science Foundation of Jiangsu Province,China (Grant No.BK20211584)Xuzhou Science and Technology Planning Project,China (Grant No.KC21004).
文摘The nonlinear flow properties of Newtonian fluids through crossed fractures are estimated by considering the influences of length,aperture,and surface roughness of fractures.A total of 252 computational runs are performed by creating 36 computational domains,in which the Navier-Stokes equations are solved.The results show that the nonlinear relationship between flow rate and hydraulic gradient follows Forchheimer’s law–based equation.When the hydraulic gradient is small(i.e.,10^(−6)),the streamlines are parallel to the fracture walls,indicating a linear streamline distribution.When the hydraulic gradient is large(i.e.,10^(0)),the streamlines are disturbed by a certain number of eddies,indicating a nonlinear streamline distribution.The patterns of eddy distributions depend on the length,aperture,and surface roughness of fractures.With the increment of hydraulic gradient from 10^(−6) to 10^(0),the ratio of flow rate to hydraulic gradient holds constants and then decreases slightly and finally decreases robustly.The fluid flow experiences a linear flow regime,a weakly nonlinear regime,and a strongly nonlinear regime,respectively.The critical hydraulic gradient ranges from 3.27×10^(−5) to 5.82×10^(−2) when fracture length=20–100mmandmechanical aperture=1–5mm.The joint roughness coefficient plays a negligible role in the variations in critical hydraulic gradient compared with fracture length and/or mechanical aperture.The critical hydraulic gradient decreases with increasing mechanical aperture,following power-law relationships.The parameters in the functions are associated with fracture length.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61222501 and 61335004the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No 20111103110019
文摘Polarization-stable 980 nm oxide-confined vertical-cavity surface-emitting lasers with 3 μm diamond-shaped aper- ture are fabricated by comprehensively utilizing the anisotropic properties of wet etching and wet nitrogen oxida- tion of Ⅲ-Ⅴ semiconductor materials. Polarization-stable operation along the major axis of the diamond-shaped oxide aperture with 11 dB orthogonal polarization suppression ratio is achieved in a temperature range of 15-55℃ from the threshold to 4 mA.
