A numerical model for bilayer organic light-emitting diodes (OLEDs) is developed under the basis of trapped charge limited conduction.The dependences of the current density on the layer thickness,trap properties and c...A numerical model for bilayer organic light-emitting diodes (OLEDs) is developed under the basis of trapped charge limited conduction.The dependences of the current density on the layer thickness,trap properties and carrier mobility of the hole transport layer (HTL) and emission layer (EML) in bilayer OLEDs of the structure anode/HTL/EML/cathode are numerically investigated.It is found that,for given values of the total thickness of organic layers,reduced depth of trap,total density of trap,and carrier mobility of HTL as well as EML,there exists an optimal thickness ratio of HTL to EML,by which a maximal quantum efficiency can be achieved.Through optimization of the thickness ratio,an enhancement of current density and quantum efficiency of as much as two orders of magnitude can be obtained.The dependences of the optimal thickness ratio to the characteristic trap energy,total density of trap and carrier mobility are numerically analyzed.展开更多
A Y2O3 particle enhanced Ni/TiC composite coating was fabricated in-situ on a TC4 Ti alloy by laser surface cladding. The phase component, microstructure, composition distribution and properties of the composite layer...A Y2O3 particle enhanced Ni/TiC composite coating was fabricated in-situ on a TC4 Ti alloy by laser surface cladding. The phase component, microstructure, composition distribution and properties of the composite layer were investigated. The composite layer has graded microstructures and compositions, due to the fast melting followed by rapid solidification and cooling during laser cladding. The TiC powders are completely dissolved into the melted layer during melting and segregated as fine dendrites when solidified. The size of TiC dendrites decreases with increasing depth. Y2O3 fine particles distribute in the whole clad layer. The Y2O3 particle enhanced Ni/TiC composite layer has a quite uniform hardness along depth with a maximum value of HV1380, which is 4 times higher than the initial hardness. The wear resistance of the Ti alloy is significantly improved after laser cladding due to the high hardness of the composite coating.展开更多
The effect of changing Be doping concentration in GaAs layer on the integrated photosensitivity for nega- tive-electron-affinity GaAs photocathodes is investigated. Two GaAs samples with the monolayer structure and th...The effect of changing Be doping concentration in GaAs layer on the integrated photosensitivity for nega- tive-electron-affinity GaAs photocathodes is investigated. Two GaAs samples with the monolayer structure and the muhilayer structure are grown by molecular beam epitaxy. The former has a constant Be concentration of 1 × 10^19 cm^-3, while the latter includes four layers with Be doping concentrations of 1 × 10^19, 7 × 10^18, 4 × 10^18, and 1 × 10^18 cm^-3 from the bottom to the surface. Negative-electron-affinity GaAs photocathodes are fabricated by exciting the sample surfaces with alternating input of Cs and O in the high vacuum system. The spectral response results measured by the on-line spectral response measurement system show that the integrated photosensitivity of the photocathode with the muhilayer structure enhanced by at least 50% as compared to that of the monolayer structure. This attributes to the improvement in the crystal quality and the increase in the surface escape probability. Different stress situations are observed on GaAs samples with monolayer structure and muhilayer structure, respectively.展开更多
The effects of the mixing of wave transport flux residual(Bvl) on the upper ocean is studied through carrying out the control run(CR) and a series of sensitive runs(SR) with ROMS model.In this study,the important role...The effects of the mixing of wave transport flux residual(Bvl) on the upper ocean is studied through carrying out the control run(CR) and a series of sensitive runs(SR) with ROMS model.In this study,the important role of Bvl is revealed by comparing the ocean temperature,statistical analysis of errors and evaluating the mixed layer depth.It is shown that the overestimated SST is improved effectively when the wave-induced mixing is incorporated to the vertical mixing scheme.As can be seen from the vertical structure of temperature 28℃ isotherm changes from 20 min CR to 35 m in SR3,which is more close to the observation.Statistic analysis shows that the root-mean-square errors of the temperature in 10 m are reduced and the correlation between model results and observation data are increased after considering the effect of Bvl.The numerical results of the ocean temperature show improvement in summer and in tropical zones in winter,especially in the strong current regions in summer.In August the mixed layer depth(MLD) which is defined as the depth that the temperature has changed 0.5℃ from the reference depth of 10 m is further analyzed.The simulation results have a close relationship with undetermined coefficient of Bvl,sensitivity studies show that a coefficient about 0.1 is reasonable value in the model.展开更多
During August 2013,a mobile Rayleigh lidar was deployed in Lhasa,Tibet(29.6°N,91.0°E) for making measurements of middle atmosphere densities and temperatures from 30 to 90 km.In this paper,the authors presen...During August 2013,a mobile Rayleigh lidar was deployed in Lhasa,Tibet(29.6°N,91.0°E) for making measurements of middle atmosphere densities and temperatures from 30 to 90 km.In this paper,the authors present the initial results from this scientific campaign,Middle Atmosphere Remote Mobile Observatory in Tibet(MARMOT),and compared the results to the MSIS-00(Mass Spectrometer and Incoherent Scatter) model.This work will advance our understanding of middle atmosphere dynamic processes,especially over the Tibetan Plateau area.展开更多
AIM To investigate the correlation of iodine concentration(IC) generated by spectral computed tomography(CT) with micro-vessel density(MVD) and vascular endothelial growth factor(VEGF) expression in patients with adva...AIM To investigate the correlation of iodine concentration(IC) generated by spectral computed tomography(CT) with micro-vessel density(MVD) and vascular endothelial growth factor(VEGF) expression in patients with advanced gastric carcinoma(GC).METHODS Thirty-four advanced GC patients underwent abdominal enhanced CT in the gemstone spectral imaging mode. The IC of the primary lesion in the arterial phase(AP) and venous phase(VP) were measured, and were then normalized against that in the aorta to provide the normalized IC(nI C). MVD and VEGF were detected by immunohistochemical assays, using CD34 and VEGF-A antibodies, respectively. Correlations of nI C with MVD, VEGF, and clinical-pathological features were analyzed.RESULTS Both nI Cs correlated linearly with MVD and were higher in the primary lesion site than in the normal control site, but were not correlated with VEGF expression. After stratification by clinical-pathological subtypes, nI C-AP showed a statistically significant correlation with MVD, particularly in the group with tumors at stage T4, without nodular involvement, of a mixed Lauren type, where the tumor was located at the antrum site, and occurred in female individuals. nI C-VP showed a positive correlation with MVD in the group with the tumor at stage T4 and above, had nodular involvement, was poorly differentiated, was located at the pylorus site, of a mixed and diffused Lauren subtype, and occurred in male individuals. nI C-AP and nI C-VP showed significant differences in terms of histological differentiation and Lauren subtype.CONCLUSION The IC detected by spectral CT correlated with the MVD. n IC-AP and n IC-VP can reflect angiogenesis in different pathological subgroups of advanced GC.展开更多
The optical parameters for three samples of intrinsic, doped Si and doped Mg (Al x Ga 1- x ) y In 1- y P prepared by the MOCVD on GaAs substrate were measured by using ellipsometry and were calc...The optical parameters for three samples of intrinsic, doped Si and doped Mg (Al x Ga 1- x ) y In 1- y P prepared by the MOCVD on GaAs substrate were measured by using ellipsometry and were calculated by the two-layer absorption film model. The results obtained were discussed. The grown rates and thickness of oxidic layer on the intrinsic (Al x Ga 1- x ) y In 1- y P surface exposed in the atmosphere were studied. A linear dependence of oxidic layer thickness on the time was obtained.展开更多
A compound coating of electrically conductive and visible transparent film and laser protective film has been developed,this coating has light densities of no less than 4 against 0.53 μm and no less than 3 against 1....A compound coating of electrically conductive and visible transparent film and laser protective film has been developed,this coating has light densities of no less than 4 against 0.53 μm and no less than 3 against 1.06 μm in the range of ±30° angular field.The average transmittance value as high as 60% from 0.4 μm to 0.7 μm has been achieved.The structures of the laser protective filters are compared.The refractive index of a compound material used in the matching layer has been given.Measured results of the laser protective film coating are compared with that of the compound coating.展开更多
A dust concentration imaging system based on optical tomography is proposed to monitor concentration variations of coal dust in a mine.Concentration profiles,rather than just a point value,of coal dust concentrations ...A dust concentration imaging system based on optical tomography is proposed to monitor concentration variations of coal dust in a mine.Concentration profiles,rather than just a point value,of coal dust concentrations are the goal of this method.An optical sensor array is employed to realize an optical sensing field of the coal dust concentration during on-line monitoring.A novel image reconstruction algorithm,called the simultaneous iterative reconstruction technique(SIRT),is compared to the well known linear,back projection algorithm(LBP).The SIRT was applied to the present problem and tested by modeling.The disadvantage of the SIRT is a slow speed but some improvements have been made by adding a weighting function that reduces the relative error to 1.7% from 3.1% for 50 iterations.The results of image reconstruction are presented for both simulated and real objects.They prove that the optical tomography technique,based on a multi-source fan projection scheme,can be an effective approach for estimating coal dust distribution.This system can be applied in real time for continuous measurements in a mine.展开更多
A new method for the determination of Fe by thin layer resin phase spectrophotometry in alkali condition was reported. The complex anion formed by Fe(Ⅱ) and VA was absorbed on the 717w resin and Fe was determined b...A new method for the determination of Fe by thin layer resin phase spectrophotometry in alkali condition was reported. The complex anion formed by Fe(Ⅱ) and VA was absorbed on the 717w resin and Fe was determined by making thin layer. This method had a high sensitivity (ε620= 3.0×10^5L/mol.cm), which was 15 times higher than that of liquid phase spectrophotometry. It had been proved a satisfactory precision (5.01μg Fe, n=6, RSD=1.8%). The trace Fe in natural water was determined and the recovery was 97%.展开更多
In this paper, a new thin-layer ion-exchange resin phase analytical method is introduced. It is based on that, the bismuthous cation can associate with iodic anions, so as to formed an anion complex [BiI4-] in a stron...In this paper, a new thin-layer ion-exchange resin phase analytical method is introduced. It is based on that, the bismuthous cation can associate with iodic anions, so as to formed an anion complex [BiI4-] in a strong acidic environments. This anion complex can also exchanges with a weaker anions on the surface active site of anion exchange resin, so that a [R+] [BiI4-] solid phase binary associational system is produced. Owing to the solid system is a great many dispersive particulates, it can be pressed to a thin-layer by press tools of the so called 搕hin-layer resin phase?or 搑esin phase? and using this solid association system spectrophotometry for the determination of trace metals. So it can increase the analytical sensitivity. This association system exhibits maximum absorbance at 460nm, and obeys Beer抯 law over the concentration range 0.01ug/ml^1.20ug/ml of bismuthous(III). It has a molar absorptivity of 7.1×105 [L/mol穋m]. It indicated the resin phase spectrophotometry is a sensitive analytical method for trace bismuthous. It is 18 times higher than routine aqueous spectrophotometry. The relative standard deviations is 1.82% (n=6) for the measurements of 0.5ug/ml Bi(III). The detection limit of Bismuthous(III) is 1.4×10-8mol/L. The method has applied to the analysis Bi(III) in environmental water samples.展开更多
The exchanges of NOx between snow and air have significant impact on the atmospheric components and photochemical processes in the overlying boundary layer. Such exchanges increase the oxidizing capacity of the atmosp...The exchanges of NOx between snow and air have significant impact on the atmospheric components and photochemical processes in the overlying boundary layer. Such exchanges increase the oxidizing capacity of the atmosphere and may have a crucial impact on the air signals that are retrieved from ice cores. In the recent years, sunlit snow and ice have been demonstrated to be important NOx sources in the polar atmospheric boundary layer. This paper makes a thorough review on the release of NOx from snow and ice, including field observations and experimental evidences, release mechanisms and influential parameters that affect such a release process, polar NOx concentrations and fluxes, and environmental impacts of the chemical processes of NOx in the polar atmospheric boundary layer. In the Tibetan Plateau, the released NOx observed recently in the sunlit snow/ice-cover is 1-order magnitude more than that in polar regions, but further scientific research is still needed to reveal its impact on the atmospheric oxidizing capacity.展开更多
Turbulent kinetic energy budgets are presented for a highly curved flow generated by the collision of plane wall turbulent jet with a low-velocity boundary layer. The different terms are obtained in the vertical plane...Turbulent kinetic energy budgets are presented for a highly curved flow generated by the collision of plane wall turbulent jet with a low-velocity boundary layer. The different terms are obtained in the vertical plane of symmetry by quadratic interpolation of the LDV (Laser Doppler Velocimetry) measurements, for a wall jet-to-boundary layer velocity ratio of 2. The results, which have relevance to flows encountered in powered-lift aircraft operating in ground effect, quantify the structure of the complex ground vortex flow. The analysis of turbulent energy equation terms using the measured data revealed that production by normal and shear stresses are both very important to the turbulent structure of the impact zone of the ground vortex. This is an indication that the modeling of turbulence of a ground vortex requires a good representation of the production by normal stresses which is most important in the collision zone.展开更多
Canopy foliar Nitrogen Concentration (CNC) is one of the most important parameters influencing vegetation productivity in forest ecosystems. In this study, we explored the potential of imaging spectrometry (hypersp...Canopy foliar Nitrogen Concentration (CNC) is one of the most important parameters influencing vegetation productivity in forest ecosystems. In this study, we explored the potential of imaging spectrometry (hyperspectral) remote sensing of CNC in conifer plantations in China’s subtropical red soil hilly region. Our analysis included data from 57 field plots scattered across two transects covered by Hyperion images. Single regression and partial least squares regression (PLSR) were used to explore the relationships between CNC and hyperspectral data. The correlations between CNC and nearinfrared relfectance (NIR) were consistent in three data subsets (subsets A-C). For all subsets, CNC was signiifcantly positively correlated with NIR in the two transects (R2=0.29, 0.33 and 0.36, P<0.05 or P<0.01, respectively). It suggested that the NIR-CNC relationship exist despite a weak one, and the relationship may be weakened by the single canopy structure. Besides, we also applied a shortwave infrared (SWIR) index - Normalized Difference Nitrogen Index (NDNI) to estimate CNC variation. NDNI presented a signiifcant positive correlation with CNC in different subsets, but like NIR, it was also with low coefifcient of determination (R2=0.38, 0.20 and 0.17, P<0.01, respectively). Also, the correlations between CNC and the entire spectrum reflectance (or its derivative and logarithmic transformation) by PLSR owned different signiifcance in various subsets. We did not ifnd the very robust relationship like previous literatures, so the data we used were checked again. The paired T-test was applied to estimate the inlfuence of inter-annual variability of FNC on the relationships between CNC and Hyperion data. The inter-annual mismatch between period of ifeldwork and Hyperion acquisition had no inlfuence on the correlations of CNC-Hyperion data. Meanwhile, we pointed out that the lack of the canopy structure variation in conifer plantation area may lead to these weak relationships.展开更多
TiCx-NiTi2/Ti cermet composite coatings C1 and C2 with gradient TiCx reinforcements were prepared on TC4 titanium alloy by laser cladding method.The microstructure and phase compositions were analyzed by means of scan...TiCx-NiTi2/Ti cermet composite coatings C1 and C2 with gradient TiCx reinforcements were prepared on TC4 titanium alloy by laser cladding method.The microstructure and phase compositions were analyzed by means of scanning electron microscopy(SEM),energy-dispersive spectroscopy(EDS)and X-ray diffraction(XRD)meter.The TiCx exhibited a dendritic microstructure,and homogeneously dispersed in the Ti-based matrix where NiTi2 was embedded.With increasing ingredient supercooling,temperature gradient and cooling temperature,the dendrites displayed a finer morphology with longer primary trunks and intensified side branches in the dilution zone.But the smoothed,coarse columnar ones became dominant in the upper clad layer due to the repeated energy input during multi-track cladding.The Vickers microhardness presented a linear change trend through the cross-sections,which well confirmed the gradient distribution of TiCx.With more TiCx,C1 presented higher hardness than C2.展开更多
We successfully investigate an optical bistability phenomenon in a layered structure consisting of Kretschmann configuration involving the Kerr-type nonlinear and the silver film. Pure theoretical approaches are emplo...We successfully investigate an optical bistability phenomenon in a layered structure consisting of Kretschmann configuration involving the Kerr-type nonlinear and the silver film. Pure theoretical approaches are employed to investigate that the surface plasmon could easily be coupled and both the reflection and transmission curves versus the incident intensity forms optical bistability. The transmission curves are greatly influenced by the thickness of the second silver film. These results may be useful for designing novel surface plasmon-based optical devices and will be essential for future classical and quantum information processes.展开更多
Objective:To investigate the value of optic disc retinal nerve fiber layer(RNFL)thickness in the diagnosis of diabetic peripheral neuropathy(DPN).Methods:Ninety patients with type 2 diabetes,including 60 patients with...Objective:To investigate the value of optic disc retinal nerve fiber layer(RNFL)thickness in the diagnosis of diabetic peripheral neuropathy(DPN).Methods:Ninety patients with type 2 diabetes,including 60 patients without DPN(NDPN group)and 30 patients with DPN(DPN group),and 30 healthy participants(normal group)were enrolled.Optical coherence tomography(OCT)was used to measure the four quadrants and the overall average RNFL thickness of the optic disc.The receiver operator characteristic curve was drawn and the area under the curve(AUC)was calculated to evaluate the diagnostic value of RNFL thickness in the optic disc area for DPN.Results:The RNFL thickness of the DPN group was thinner than those of the normal and NDPN groups in the overall average((101.07±12.40)μm vs.(111.07±6.99)μm and(109.25±6.90)μm),superior quadrant((123.00±19.04)μm vs.(138.93±14.16)μm and(134.47±14.34)μm),and inferior quadrant((129.37±17.50)μm vs.(143.60±12.22)μm and(144.48±14.10)μm),and the differences were statistically significant.The diagnostic efficiencies of the overall average,superior quadrant,and inferior quadrant RNFL thicknesses,and a combined index of superior and inferior quadrant RNFL thicknesses were similar,and the AUCs were 0.739(95%confidence interval(CI)0.635–0.826),0.683(95%CI 0.576–0.778),0.755(95%CI 0.652–0.840),and 0.773(95%CI 0.672–0.854),respectively.The diagnostic sensitivity of RNFL thickness in the superior quadrant reached 93.33%.Conclusions:The thickness of the RNFL in the optic disc can be used as a diagnostic method for DPN.展开更多
We investigated the higher structure of konjac glucomannan (KGM) in the amorphous state and solution using a laser particle size analyzer and a water activity meter. The results show that the thermodynamic structures ...We investigated the higher structure of konjac glucomannan (KGM) in the amorphous state and solution using a laser particle size analyzer and a water activity meter. The results show that the thermodynamic structures of native KGM were primarily composed of the lamella structure units, which involve both granular crystalline and amorphous regions, and that the connection zones of such units contained both loose and tight aggregation regions. The value of surface tension (σ) of native KGM, resting with the density of its hydroxyl groups' self-association, was an important parameter to analyze the higher structures of native KGM in the thermodynamic swelling model of native KGM.展开更多
文摘A numerical model for bilayer organic light-emitting diodes (OLEDs) is developed under the basis of trapped charge limited conduction.The dependences of the current density on the layer thickness,trap properties and carrier mobility of the hole transport layer (HTL) and emission layer (EML) in bilayer OLEDs of the structure anode/HTL/EML/cathode are numerically investigated.It is found that,for given values of the total thickness of organic layers,reduced depth of trap,total density of trap,and carrier mobility of HTL as well as EML,there exists an optimal thickness ratio of HTL to EML,by which a maximal quantum efficiency can be achieved.Through optimization of the thickness ratio,an enhancement of current density and quantum efficiency of as much as two orders of magnitude can be obtained.The dependences of the optimal thickness ratio to the characteristic trap energy,total density of trap and carrier mobility are numerically analyzed.
基金Projects (51101096, 51002093) supported by the National Natural Science Foundation of ChinaProject (1052nm05000) supported by Special Foundation of the Shanghai Science and Technology Commission for Nano-Materials ResearchProject (J51042) supported by Leading Academic Discipline Project of the Shanghai Education Commission, China
文摘A Y2O3 particle enhanced Ni/TiC composite coating was fabricated in-situ on a TC4 Ti alloy by laser surface cladding. The phase component, microstructure, composition distribution and properties of the composite layer were investigated. The composite layer has graded microstructures and compositions, due to the fast melting followed by rapid solidification and cooling during laser cladding. The TiC powders are completely dissolved into the melted layer during melting and segregated as fine dendrites when solidified. The size of TiC dendrites decreases with increasing depth. Y2O3 fine particles distribute in the whole clad layer. The Y2O3 particle enhanced Ni/TiC composite layer has a quite uniform hardness along depth with a maximum value of HV1380, which is 4 times higher than the initial hardness. The wear resistance of the Ti alloy is significantly improved after laser cladding due to the high hardness of the composite coating.
文摘The effect of changing Be doping concentration in GaAs layer on the integrated photosensitivity for nega- tive-electron-affinity GaAs photocathodes is investigated. Two GaAs samples with the monolayer structure and the muhilayer structure are grown by molecular beam epitaxy. The former has a constant Be concentration of 1 × 10^19 cm^-3, while the latter includes four layers with Be doping concentrations of 1 × 10^19, 7 × 10^18, 4 × 10^18, and 1 × 10^18 cm^-3 from the bottom to the surface. Negative-electron-affinity GaAs photocathodes are fabricated by exciting the sample surfaces with alternating input of Cs and O in the high vacuum system. The spectral response results measured by the on-line spectral response measurement system show that the integrated photosensitivity of the photocathode with the muhilayer structure enhanced by at least 50% as compared to that of the monolayer structure. This attributes to the improvement in the crystal quality and the increase in the surface escape probability. Different stress situations are observed on GaAs samples with monolayer structure and muhilayer structure, respectively.
基金supported by the National Key Basic Research and Development Program(2010CB950404)the National High Technology Research and Development Program(2013AA09A506)
文摘The effects of the mixing of wave transport flux residual(Bvl) on the upper ocean is studied through carrying out the control run(CR) and a series of sensitive runs(SR) with ROMS model.In this study,the important role of Bvl is revealed by comparing the ocean temperature,statistical analysis of errors and evaluating the mixed layer depth.It is shown that the overestimated SST is improved effectively when the wave-induced mixing is incorporated to the vertical mixing scheme.As can be seen from the vertical structure of temperature 28℃ isotherm changes from 20 min CR to 35 m in SR3,which is more close to the observation.Statistic analysis shows that the root-mean-square errors of the temperature in 10 m are reduced and the correlation between model results and observation data are increased after considering the effect of Bvl.The numerical results of the ocean temperature show improvement in summer and in tropical zones in winter,especially in the strong current regions in summer.In August the mixed layer depth(MLD) which is defined as the depth that the temperature has changed 0.5℃ from the reference depth of 10 m is further analyzed.The simulation results have a close relationship with undetermined coefficient of Bvl,sensitivity studies show that a coefficient about 0.1 is reasonable value in the model.
基金supported by the National Natural Science Foundation of China (NSFC) (Grant No.41127901)the National Basic Research Program of China (973 program,Grant No.2010CB428601)the "100 Technical Talents" Program of the Chinese Academy of Sciences (CAS)
文摘During August 2013,a mobile Rayleigh lidar was deployed in Lhasa,Tibet(29.6°N,91.0°E) for making measurements of middle atmosphere densities and temperatures from 30 to 90 km.In this paper,the authors present the initial results from this scientific campaign,Middle Atmosphere Remote Mobile Observatory in Tibet(MARMOT),and compared the results to the MSIS-00(Mass Spectrometer and Incoherent Scatter) model.This work will advance our understanding of middle atmosphere dynamic processes,especially over the Tibetan Plateau area.
基金Supported by the National Natural Science Foundation of China,No.81271573
文摘AIM To investigate the correlation of iodine concentration(IC) generated by spectral computed tomography(CT) with micro-vessel density(MVD) and vascular endothelial growth factor(VEGF) expression in patients with advanced gastric carcinoma(GC).METHODS Thirty-four advanced GC patients underwent abdominal enhanced CT in the gemstone spectral imaging mode. The IC of the primary lesion in the arterial phase(AP) and venous phase(VP) were measured, and were then normalized against that in the aorta to provide the normalized IC(nI C). MVD and VEGF were detected by immunohistochemical assays, using CD34 and VEGF-A antibodies, respectively. Correlations of nI C with MVD, VEGF, and clinical-pathological features were analyzed.RESULTS Both nI Cs correlated linearly with MVD and were higher in the primary lesion site than in the normal control site, but were not correlated with VEGF expression. After stratification by clinical-pathological subtypes, nI C-AP showed a statistically significant correlation with MVD, particularly in the group with tumors at stage T4, without nodular involvement, of a mixed Lauren type, where the tumor was located at the antrum site, and occurred in female individuals. nI C-VP showed a positive correlation with MVD in the group with the tumor at stage T4 and above, had nodular involvement, was poorly differentiated, was located at the pylorus site, of a mixed and diffused Lauren subtype, and occurred in male individuals. nI C-AP and nI C-VP showed significant differences in terms of histological differentiation and Lauren subtype.CONCLUSION The IC detected by spectral CT correlated with the MVD. n IC-AP and n IC-VP can reflect angiogenesis in different pathological subgroups of advanced GC.
文摘The optical parameters for three samples of intrinsic, doped Si and doped Mg (Al x Ga 1- x ) y In 1- y P prepared by the MOCVD on GaAs substrate were measured by using ellipsometry and were calculated by the two-layer absorption film model. The results obtained were discussed. The grown rates and thickness of oxidic layer on the intrinsic (Al x Ga 1- x ) y In 1- y P surface exposed in the atmosphere were studied. A linear dependence of oxidic layer thickness on the time was obtained.
文摘A compound coating of electrically conductive and visible transparent film and laser protective film has been developed,this coating has light densities of no less than 4 against 0.53 μm and no less than 3 against 1.06 μm in the range of ±30° angular field.The average transmittance value as high as 60% from 0.4 μm to 0.7 μm has been achieved.The structures of the laser protective filters are compared.The refractive index of a compound material used in the matching layer has been given.Measured results of the laser protective film coating are compared with that of the compound coating.
基金supported by the Key Project in the National Science & Technology Pillar Program during the twelfth Five-Year Planperiod (No. SQ2012BAJY3504-08)
文摘A dust concentration imaging system based on optical tomography is proposed to monitor concentration variations of coal dust in a mine.Concentration profiles,rather than just a point value,of coal dust concentrations are the goal of this method.An optical sensor array is employed to realize an optical sensing field of the coal dust concentration during on-line monitoring.A novel image reconstruction algorithm,called the simultaneous iterative reconstruction technique(SIRT),is compared to the well known linear,back projection algorithm(LBP).The SIRT was applied to the present problem and tested by modeling.The disadvantage of the SIRT is a slow speed but some improvements have been made by adding a weighting function that reduces the relative error to 1.7% from 3.1% for 50 iterations.The results of image reconstruction are presented for both simulated and real objects.They prove that the optical tomography technique,based on a multi-source fan projection scheme,can be an effective approach for estimating coal dust distribution.This system can be applied in real time for continuous measurements in a mine.
文摘A new method for the determination of Fe by thin layer resin phase spectrophotometry in alkali condition was reported. The complex anion formed by Fe(Ⅱ) and VA was absorbed on the 717w resin and Fe was determined by making thin layer. This method had a high sensitivity (ε620= 3.0×10^5L/mol.cm), which was 15 times higher than that of liquid phase spectrophotometry. It had been proved a satisfactory precision (5.01μg Fe, n=6, RSD=1.8%). The trace Fe in natural water was determined and the recovery was 97%.
文摘In this paper, a new thin-layer ion-exchange resin phase analytical method is introduced. It is based on that, the bismuthous cation can associate with iodic anions, so as to formed an anion complex [BiI4-] in a strong acidic environments. This anion complex can also exchanges with a weaker anions on the surface active site of anion exchange resin, so that a [R+] [BiI4-] solid phase binary associational system is produced. Owing to the solid system is a great many dispersive particulates, it can be pressed to a thin-layer by press tools of the so called 搕hin-layer resin phase?or 搑esin phase? and using this solid association system spectrophotometry for the determination of trace metals. So it can increase the analytical sensitivity. This association system exhibits maximum absorbance at 460nm, and obeys Beer抯 law over the concentration range 0.01ug/ml^1.20ug/ml of bismuthous(III). It has a molar absorptivity of 7.1×105 [L/mol穋m]. It indicated the resin phase spectrophotometry is a sensitive analytical method for trace bismuthous. It is 18 times higher than routine aqueous spectrophotometry. The relative standard deviations is 1.82% (n=6) for the measurements of 0.5ug/ml Bi(III). The detection limit of Bismuthous(III) is 1.4×10-8mol/L. The method has applied to the analysis Bi(III) in environmental water samples.
基金supported by the Fund of Polar Scientific Research(No.20080216) of State Ocean Administration, Chinaby Chinese Natural Science Foundation(No. 20407001,No.40701170)
文摘The exchanges of NOx between snow and air have significant impact on the atmospheric components and photochemical processes in the overlying boundary layer. Such exchanges increase the oxidizing capacity of the atmosphere and may have a crucial impact on the air signals that are retrieved from ice cores. In the recent years, sunlit snow and ice have been demonstrated to be important NOx sources in the polar atmospheric boundary layer. This paper makes a thorough review on the release of NOx from snow and ice, including field observations and experimental evidences, release mechanisms and influential parameters that affect such a release process, polar NOx concentrations and fluxes, and environmental impacts of the chemical processes of NOx in the polar atmospheric boundary layer. In the Tibetan Plateau, the released NOx observed recently in the sunlit snow/ice-cover is 1-order magnitude more than that in polar regions, but further scientific research is still needed to reveal its impact on the atmospheric oxidizing capacity.
文摘Turbulent kinetic energy budgets are presented for a highly curved flow generated by the collision of plane wall turbulent jet with a low-velocity boundary layer. The different terms are obtained in the vertical plane of symmetry by quadratic interpolation of the LDV (Laser Doppler Velocimetry) measurements, for a wall jet-to-boundary layer velocity ratio of 2. The results, which have relevance to flows encountered in powered-lift aircraft operating in ground effect, quantify the structure of the complex ground vortex flow. The analysis of turbulent energy equation terms using the measured data revealed that production by normal and shear stresses are both very important to the turbulent structure of the impact zone of the ground vortex. This is an indication that the modeling of turbulence of a ground vortex requires a good representation of the production by normal stresses which is most important in the collision zone.
基金the National Basic Research Program of China on Global Change(Grant No.2010CB950701,2010CB833503)the Chinese Academy of Sciences for Strategic Priority Research Program(Grant No.XDA05050602-1)National Natural Science Foundation of China(Grant No.31070438)
文摘Canopy foliar Nitrogen Concentration (CNC) is one of the most important parameters influencing vegetation productivity in forest ecosystems. In this study, we explored the potential of imaging spectrometry (hyperspectral) remote sensing of CNC in conifer plantations in China’s subtropical red soil hilly region. Our analysis included data from 57 field plots scattered across two transects covered by Hyperion images. Single regression and partial least squares regression (PLSR) were used to explore the relationships between CNC and hyperspectral data. The correlations between CNC and nearinfrared relfectance (NIR) were consistent in three data subsets (subsets A-C). For all subsets, CNC was signiifcantly positively correlated with NIR in the two transects (R2=0.29, 0.33 and 0.36, P<0.05 or P<0.01, respectively). It suggested that the NIR-CNC relationship exist despite a weak one, and the relationship may be weakened by the single canopy structure. Besides, we also applied a shortwave infrared (SWIR) index - Normalized Difference Nitrogen Index (NDNI) to estimate CNC variation. NDNI presented a signiifcant positive correlation with CNC in different subsets, but like NIR, it was also with low coefifcient of determination (R2=0.38, 0.20 and 0.17, P<0.01, respectively). Also, the correlations between CNC and the entire spectrum reflectance (or its derivative and logarithmic transformation) by PLSR owned different signiifcance in various subsets. We did not ifnd the very robust relationship like previous literatures, so the data we used were checked again. The paired T-test was applied to estimate the inlfuence of inter-annual variability of FNC on the relationships between CNC and Hyperion data. The inter-annual mismatch between period of ifeldwork and Hyperion acquisition had no inlfuence on the correlations of CNC-Hyperion data. Meanwhile, we pointed out that the lack of the canopy structure variation in conifer plantation area may lead to these weak relationships.
基金supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China(Grant No.2011BAE12B03)the National Natural Science Foundation of China(Grant No.11372110)
文摘TiCx-NiTi2/Ti cermet composite coatings C1 and C2 with gradient TiCx reinforcements were prepared on TC4 titanium alloy by laser cladding method.The microstructure and phase compositions were analyzed by means of scanning electron microscopy(SEM),energy-dispersive spectroscopy(EDS)and X-ray diffraction(XRD)meter.The TiCx exhibited a dendritic microstructure,and homogeneously dispersed in the Ti-based matrix where NiTi2 was embedded.With increasing ingredient supercooling,temperature gradient and cooling temperature,the dendrites displayed a finer morphology with longer primary trunks and intensified side branches in the dilution zone.But the smoothed,coarse columnar ones became dominant in the upper clad layer due to the repeated energy input during multi-track cladding.The Vickers microhardness presented a linear change trend through the cross-sections,which well confirmed the gradient distribution of TiCx.With more TiCx,C1 presented higher hardness than C2.
基金supported by the National Basic Research Program of China (Grant No. 2010CB923202)
文摘We successfully investigate an optical bistability phenomenon in a layered structure consisting of Kretschmann configuration involving the Kerr-type nonlinear and the silver film. Pure theoretical approaches are employed to investigate that the surface plasmon could easily be coupled and both the reflection and transmission curves versus the incident intensity forms optical bistability. The transmission curves are greatly influenced by the thickness of the second silver film. These results may be useful for designing novel surface plasmon-based optical devices and will be essential for future classical and quantum information processes.
基金the Science and Technology Plan Project of Quanzhou(Nos.2018Z114,2018Z115,and 2019N104S)the Qihang Fund of Fujian Medical University(No.2016QH072)the Health Research Talent Training Project of Fujian(No.2019-ZQN-66),China。
文摘Objective:To investigate the value of optic disc retinal nerve fiber layer(RNFL)thickness in the diagnosis of diabetic peripheral neuropathy(DPN).Methods:Ninety patients with type 2 diabetes,including 60 patients without DPN(NDPN group)and 30 patients with DPN(DPN group),and 30 healthy participants(normal group)were enrolled.Optical coherence tomography(OCT)was used to measure the four quadrants and the overall average RNFL thickness of the optic disc.The receiver operator characteristic curve was drawn and the area under the curve(AUC)was calculated to evaluate the diagnostic value of RNFL thickness in the optic disc area for DPN.Results:The RNFL thickness of the DPN group was thinner than those of the normal and NDPN groups in the overall average((101.07±12.40)μm vs.(111.07±6.99)μm and(109.25±6.90)μm),superior quadrant((123.00±19.04)μm vs.(138.93±14.16)μm and(134.47±14.34)μm),and inferior quadrant((129.37±17.50)μm vs.(143.60±12.22)μm and(144.48±14.10)μm),and the differences were statistically significant.The diagnostic efficiencies of the overall average,superior quadrant,and inferior quadrant RNFL thicknesses,and a combined index of superior and inferior quadrant RNFL thicknesses were similar,and the AUCs were 0.739(95%confidence interval(CI)0.635–0.826),0.683(95%CI 0.576–0.778),0.755(95%CI 0.652–0.840),and 0.773(95%CI 0.672–0.854),respectively.The diagnostic sensitivity of RNFL thickness in the superior quadrant reached 93.33%.Conclusions:The thickness of the RNFL in the optic disc can be used as a diagnostic method for DPN.
文摘We investigated the higher structure of konjac glucomannan (KGM) in the amorphous state and solution using a laser particle size analyzer and a water activity meter. The results show that the thermodynamic structures of native KGM were primarily composed of the lamella structure units, which involve both granular crystalline and amorphous regions, and that the connection zones of such units contained both loose and tight aggregation regions. The value of surface tension (σ) of native KGM, resting with the density of its hydroxyl groups' self-association, was an important parameter to analyze the higher structures of native KGM in the thermodynamic swelling model of native KGM.