The conventional nonstationary convolutional model assumes that the seismic signal is recorded at normal incidence. Raw shot gathers are far from this assumption because of the effects of offsets. Because of such prob...The conventional nonstationary convolutional model assumes that the seismic signal is recorded at normal incidence. Raw shot gathers are far from this assumption because of the effects of offsets. Because of such problems, we propose a novel prestack nonstationary deconvolution approach. We introduce the radial trace （RT） transform to the nonstationary deconvolution, we estimate the nonstationary deconvolution factor with hyperbolic smoothing based on variable-step sampling （VSS） in the RT domain, and we obtain the high-resolution prestack nonstationary deconvolution data. The RT transform maps the shot record from the offset and traveltime coordinates to those of apparent velocity and traveltime. The ray paths of the traces in the RT better satisfy the assumptions of the convolutional model. The proposed method combines the advantages of stationary deconvolution and inverse Q filtering, without prior information for Q. The nonstationary deconvolution in the RT domain is more suitable than that in the space-time （XT） domain for prestack data because it is the generalized extension of normal incidence. Tests with synthetic and real data demonstrate that the proposed method is more effective in compensating for large-offset and deep data.展开更多
Top-emitting oxide-confined intra-cavity contact structure 980nm VCSEL is fabricated by low-pressure metal organic chemical-vapor deposition (LP-MOCVD).Self-aligning etching process and selective oxidation are applied...Top-emitting oxide-confined intra-cavity contact structure 980nm VCSEL is fabricated by low-pressure metal organic chemical-vapor deposition (LP-MOCVD).Self-aligning etching process and selective oxidation are applied for current confinement.Output light power of 10.1mW and slope efficiency of 0.462mW/mA are obtained under room temperature,pulse operation,and injection current of 28mA.The maximum light power is 13.1mW under pulse operation.Output light power of 7.1mW,lasing wavelength of 974nm,and FWHM of 0.6nm are obtained under CW condition.The study of oxide-aperture influence on threshold current and differential resistance shows that lower threshold current can be obtained with a smaller oxide-aperture diameter.展开更多
PURPOSES. To determine axial, vertical, and horizontal eye dimensions in myopi c and emmetropic eyes by using magnetic resonance imaging (MRI) and to relate th ese to different ocular expansion models of myopia develo...PURPOSES. To determine axial, vertical, and horizontal eye dimensions in myopi c and emmetropic eyes by using magnetic resonance imaging (MRI) and to relate th ese to different ocular expansion models of myopia development. METHODS. The int ernal length (cornea to retina), height and width (both retina to retina) were m easured in emmetropic and myopic eyes (up to-12 D) of 88 participants aged 18 t o 36 years. Participants were positioned supine in a clinical MRI scanner. The f ixation target was imaged straight ahead of the subject by an overhead 45°incli ned mirror. Eye images were acquired with a 7.5 cm receive-only radio frequency surface coil. Axial (horizontal through middle of eye) and sagittal (vertical t hrough visual axis) sections were taken with a T1-weighted fast spin-echo sequ ence. RESULTS. With an increase in myopic refractive correction, myopic eyes bec ame much larger in all three dimensions, but more so in length (0.35 mm/D, 95%c onfidence interval CI 0.28-0.40) than in height (0.19 mm/D, 95%CI 0.09-0.29 ) and more so in height than in width (0.10 mm/D, 95%CI 0.01-0.20). Based on h eight and length dimensions,25%and 29%of myopic eyes exclusively fitted global expansion and axial elongation models, respectively. Based on width and length dimensions, 17%and 39%of myopic eyes exclusively fitted the global expansion a nd axial elongation models, respectively. CONCLUSIONS. Although there are consid erable individual variations, in general myopic eyes are elongated relative to e mmetropic eyes, more in length than in height and even less in width. Approximat ely a quarter of the myopic participants fitted each of the global expansion or axial elongation model exclusively. The small proportions are due primarily to t he large variability in the dimensions of emmetropic eyes.展开更多
Background:This study compared SLO microperimetry scotoma size measurements with the sizes of lesions assessed with OCT in the areas of scotoma.Methods:SLO microperimetry was performed on eight patients to assess the ...Background:This study compared SLO microperimetry scotoma size measurements with the sizes of lesions assessed with OCT in the areas of scotoma.Methods:SLO microperimetry was performed on eight patients to assess the location and extent of scotoma areas.An SLO microperimetry master image was used to localize the scotoma areas in the real time OCT fundus image and to center OCT cross scans on the areas of scotoma.The sizes of the morphological changes measured by OCT were compared with the scotoma size measurements.Results:In each patient,OCT revealed a morphological change located in the area of scotoma.Scotoma sizes ranged from 465 to 3180 μ m horizontally and from 570 to 2550 μ m vertically.The corresponding lesion sizes ranged from 461 to 2660 μ m horizontally and from 523 to 2282 μ m vertically.The average difference between SLO and OCT measurements was 2.4% horizontally and 4.9% vertically.There were significant correlations between horizontal and vertical SLO and OCT measurements(Horizontal:Rsq=0.955,P < 0.0001;Vertical:Rsq=0.898,P=0.0003).Conclusion:SLO microperimetry scotoma size measurements and OCT lesion size measurements are similar to each other.Combining retinal functional testing with morphological testing provides information about the underlying causes of scotoma.展开更多
Purpose: To examine the relationship between retinal nerve fiber layer (RNFL) measurements obtained using scanning laser polarimetry with variable corneal compensation and corneal thickness measurements in ocular hype...Purpose: To examine the relationship between retinal nerve fiber layer (RNFL) measurements obtained using scanning laser polarimetry with variable corneal compensation and corneal thickness measurements in ocular hypertension (OHT) patients. Design: Observational cross- sectional study. Subjects: The study included 1 eye each from44 OHT patients and48 healthy subjects, all of similar age. All subjects had normal optic discs and normal standard automated perimetry (SAP) visual fields. Ocular hypertension patients had intraocular pressure (IOP) measurements higher than 22 mmHg. Methods: All patients underwent imagingwith the GDx VCC (Laser Diagnostic Technologies, Inc., San Diego, CA) scanning laser polarimeter. We examined the relationship between GDx VCC RNFL measurements and central corneal thickness, a risk factor for development of visual field loss among OHT patients. We also examined the relationship of GDx VCC measurements and age, IOP, SAP pattern standard deviation, and vertical cup- todisc ratio. Main Outcome Measures: Central corneal thickness (CCT) and GDx VCC RNFL thickness parameters. Results: Central corneal thickness measurements in OHT patients were significantly higher than those in healthy subjects (575± 30 μ m vs.555± 32 μ m; P=0.002). Higher GDx VCC parameter nerve fiber indicator (NFI) scores, indicating thinner RNFL, were correlated significantly with thinner CCT measurements in OHT patients (r=- 0.502; P=0.001). Ocular hypertension patients with thinner corneas (n=22; mean CCT,553± 21 μ m)- had significantly higher NFI scores than OHT patients with thicker corneas (n=22; mean CCT,598± 18 μ m) and healthy control subjects (NFI mean± standard deviation, 26.9± 9.5, 20.7± 9.8, and 19.7± 7.0, respectively; P=0.004, analysis of variance). The NFI values were not significantly different between OHT patients with thicker corneas and healthy subjects. In multivariate analysis, only age and CCT measurement were associated significantly with GDx VCC RNFL measurements in OHT eyes. Conclusions: Ocular hypertension patients with thinner corneas had significantly thinner RNFL than OHT patients with thicker corneas and healthy control subjects. These findings support the notion thatRNFL defects as assessed by the GDx VCC may represent early glaucomatous damage in OHT eyes.展开更多
Purpose.Tumour diameter,tumour height,and tumour volume are considered important pro gnostic indicators of survival in choroidal melanomas.In this study,we inves-tigated the prognostic impact on sur vival of the easil...Purpose.Tumour diameter,tumour height,and tumour volume are considered important pro gnostic indicators of survival in choroidal melanomas.In this study,we inves-tigated the prognostic impact on sur vival of the easily cal-culated volume estimate based on the assumption of a half-rotation ellipsoid.Methods.The largest tumour diam-eter and tumour height were measured by ultrasound A-and B-scan in 93patients with choroidal melanoma.Tumour volume was calculated by the half volume of a rotation el-lipsoid formula,rotated around the y-axis,and compared to tumour diameter and tumour height.A ll parameters were correlated to the clinical outcome o f the patients.Results.At the time of diagnosis,the mean dia meter was 10.4mm(range 4.1-18.9mm),and the mean height was 5.7mm(range 1.74-14.9mm).The range of the calculated tu-mour volume was between 11and 628mm 3 (mean volume 190mm 3 ).Among all patients,distant metastases occurred in 10patients(10.8%).In a univariate approach using Mantel-Haenszel log-rank test,the calculated tumour vol-ume at the time of diagnosis was the best prognostic indicator of survival followed by tu mour diameter and tu-mour height (P=0.028).When tumour volume,hori-zontal and vertical tumour diameter,age,sex,and primary tumour therapy were considered in a multivariate approach using Cox proportional Hazard model,only tumour volume turned out as a significant prognostic parameter(P=0.001).Conclusions.Calculated tumour volume is a bet-ter prognostic indicator of survival of patients with choroidal melanomas than the largest tumour di ameter and tumour height,and might be established in d aily routine.展开更多
In this companion paper, flow patterns in the upstream and downstream tubes of a sudden-expansion cross-section (SECS) in a vertical straight pipe were presented. The effect of SECS on flow patterns upstream and down...In this companion paper, flow patterns in the upstream and downstream tubes of a sudden-expansion cross-section (SECS) in a vertical straight pipe were presented. The effect of SECS on flow patterns upstream and downstream was analyzed by comparing with flow patterns in uniform cross-section vertical tubes. It is found the effect is great. There exist great instabilities of two-phase flow in the neighboring areas of the SECS both downstream and upstream.展开更多
In order to achieve uniform mixing between spray droplets and crossflow, cold-model experiment of a hollow-cone water spray in an air crossflow is investigated via a numerical simulation. The simulation cases are desi...In order to achieve uniform mixing between spray droplets and crossflow, cold-model experiment of a hollow-cone water spray in an air crossflow is investigated via a numerical simulation. The simulation cases are designed by using the orthogonal design method. The Eulerian-Lagrangian formulation is employed for modeling the droplets-crossflow two-phase flow while the realizable k-ε turbulence model is used to describe the turbulence. A new index, mixedness quality, is proposed to assess the overall mixing of the droplets in the crossflow. The simulation results demonstrate that the counter-rotating vortex pair (CVP) imposes a more significant impact on the spatial distribution than on the size distribution of the droplets. Pairs of CVP with smaller scales are preferable for achieving a better mixing. The influencing factors are listed in the following order in terms of the degree of their impact from the greatest to the least: the Sauter diameter of the initial droplets, the mixing tube diameter, the spray angle, the velocity of the inlet crossflow, and the vertical velocity of the initial droplets. A moderate droplet diameter, a smaller tube diameter, a moderate spray angle, a greater crossflow velocity and a moderate vertical velocity of the droplet are favorable for achieving a higher mixedness quality of the jet spray in a confined crossflow.展开更多
Flow patterns upstream and downstream of a sudden-contraction cross-section in a vertical straight pipe were presented. By comparing with flow patterns in uniform cross-section vertical tubes, the effect of the sudde...Flow patterns upstream and downstream of a sudden-contraction cross-section in a vertical straight pipe were presented. By comparing with flow patterns in uniform cross-section vertical tubes, the effect of the sudden change in pipe diameter on flow patterns was analyzed. Flow pattern transition mechanisms were discussed and transition criteria for flow pattern transitions were deduced accordingly using the dimensional analysis.展开更多
Considering the viscous damping of the soil and soil-pile vertical coupled vibration,a computational model of large-diameter pipe pile in layered soil was established.The analytical solution in frequency domain was de...Considering the viscous damping of the soil and soil-pile vertical coupled vibration,a computational model of large-diameter pipe pile in layered soil was established.The analytical solution in frequency domain was derived by Laplace transformation method.The responses in time domain were obtained by inverse Fourier transformation.The results of the analytical solution proposed agree well with the solutions in homogenous soil.The effects of the shear modulus and damping coefficients of the soil at both outer and inner sides of the pipe pile were researched.The results indicate that the shear modulus of the outer soil has more influence on velocity admittance than the inner soil.The smaller the shear modulus,the larger the amplitude of velocity admittance.The velocity admittance weakened by the damping of the outer soil is more obvious than that weakened by the damping of the inner soil.The displacements of the piles with the same damping coefficients of the outer soil have less difference.Moreover,the effects of the distribution of soil layers are analyzed.The results indicate that the effect of the upper soil layer on dynamic response of the pipe pile is more obvious than that of the bottom soil layer.A larger damping coefficient of the upper layer results in a smaller velocity admittance.The dynamic response of the pipe pile in layered soil is close to that of the pipe pile in homogenous soil when the properties of the upper soil layer are the same.展开更多
基金financially supported by the National Science and Technology Major Project of China(No.2011ZX05023-005-005)the National Natural Science Foundation of China(No.41274137)
文摘The conventional nonstationary convolutional model assumes that the seismic signal is recorded at normal incidence. Raw shot gathers are far from this assumption because of the effects of offsets. Because of such problems, we propose a novel prestack nonstationary deconvolution approach. We introduce the radial trace （RT） transform to the nonstationary deconvolution, we estimate the nonstationary deconvolution factor with hyperbolic smoothing based on variable-step sampling （VSS） in the RT domain, and we obtain the high-resolution prestack nonstationary deconvolution data. The RT transform maps the shot record from the offset and traveltime coordinates to those of apparent velocity and traveltime. The ray paths of the traces in the RT better satisfy the assumptions of the convolutional model. The proposed method combines the advantages of stationary deconvolution and inverse Q filtering, without prior information for Q. The nonstationary deconvolution in the RT domain is more suitable than that in the space-time （XT） domain for prestack data because it is the generalized extension of normal incidence. Tests with synthetic and real data demonstrate that the proposed method is more effective in compensating for large-offset and deep data.
文摘Top-emitting oxide-confined intra-cavity contact structure 980nm VCSEL is fabricated by low-pressure metal organic chemical-vapor deposition (LP-MOCVD).Self-aligning etching process and selective oxidation are applied for current confinement.Output light power of 10.1mW and slope efficiency of 0.462mW/mA are obtained under room temperature,pulse operation,and injection current of 28mA.The maximum light power is 13.1mW under pulse operation.Output light power of 7.1mW,lasing wavelength of 974nm,and FWHM of 0.6nm are obtained under CW condition.The study of oxide-aperture influence on threshold current and differential resistance shows that lower threshold current can be obtained with a smaller oxide-aperture diameter.
文摘PURPOSES. To determine axial, vertical, and horizontal eye dimensions in myopi c and emmetropic eyes by using magnetic resonance imaging (MRI) and to relate th ese to different ocular expansion models of myopia development. METHODS. The int ernal length (cornea to retina), height and width (both retina to retina) were m easured in emmetropic and myopic eyes (up to-12 D) of 88 participants aged 18 t o 36 years. Participants were positioned supine in a clinical MRI scanner. The f ixation target was imaged straight ahead of the subject by an overhead 45°incli ned mirror. Eye images were acquired with a 7.5 cm receive-only radio frequency surface coil. Axial (horizontal through middle of eye) and sagittal (vertical t hrough visual axis) sections were taken with a T1-weighted fast spin-echo sequ ence. RESULTS. With an increase in myopic refractive correction, myopic eyes bec ame much larger in all three dimensions, but more so in length (0.35 mm/D, 95%c onfidence interval CI 0.28-0.40) than in height (0.19 mm/D, 95%CI 0.09-0.29 ) and more so in height than in width (0.10 mm/D, 95%CI 0.01-0.20). Based on h eight and length dimensions,25%and 29%of myopic eyes exclusively fitted global expansion and axial elongation models, respectively. Based on width and length dimensions, 17%and 39%of myopic eyes exclusively fitted the global expansion a nd axial elongation models, respectively. CONCLUSIONS. Although there are consid erable individual variations, in general myopic eyes are elongated relative to e mmetropic eyes, more in length than in height and even less in width. Approximat ely a quarter of the myopic participants fitted each of the global expansion or axial elongation model exclusively. The small proportions are due primarily to t he large variability in the dimensions of emmetropic eyes.
文摘Background:This study compared SLO microperimetry scotoma size measurements with the sizes of lesions assessed with OCT in the areas of scotoma.Methods:SLO microperimetry was performed on eight patients to assess the location and extent of scotoma areas.An SLO microperimetry master image was used to localize the scotoma areas in the real time OCT fundus image and to center OCT cross scans on the areas of scotoma.The sizes of the morphological changes measured by OCT were compared with the scotoma size measurements.Results:In each patient,OCT revealed a morphological change located in the area of scotoma.Scotoma sizes ranged from 465 to 3180 μ m horizontally and from 570 to 2550 μ m vertically.The corresponding lesion sizes ranged from 461 to 2660 μ m horizontally and from 523 to 2282 μ m vertically.The average difference between SLO and OCT measurements was 2.4% horizontally and 4.9% vertically.There were significant correlations between horizontal and vertical SLO and OCT measurements(Horizontal:Rsq=0.955,P < 0.0001;Vertical:Rsq=0.898,P=0.0003).Conclusion:SLO microperimetry scotoma size measurements and OCT lesion size measurements are similar to each other.Combining retinal functional testing with morphological testing provides information about the underlying causes of scotoma.
文摘Purpose: To examine the relationship between retinal nerve fiber layer (RNFL) measurements obtained using scanning laser polarimetry with variable corneal compensation and corneal thickness measurements in ocular hypertension (OHT) patients. Design: Observational cross- sectional study. Subjects: The study included 1 eye each from44 OHT patients and48 healthy subjects, all of similar age. All subjects had normal optic discs and normal standard automated perimetry (SAP) visual fields. Ocular hypertension patients had intraocular pressure (IOP) measurements higher than 22 mmHg. Methods: All patients underwent imagingwith the GDx VCC (Laser Diagnostic Technologies, Inc., San Diego, CA) scanning laser polarimeter. We examined the relationship between GDx VCC RNFL measurements and central corneal thickness, a risk factor for development of visual field loss among OHT patients. We also examined the relationship of GDx VCC measurements and age, IOP, SAP pattern standard deviation, and vertical cup- todisc ratio. Main Outcome Measures: Central corneal thickness (CCT) and GDx VCC RNFL thickness parameters. Results: Central corneal thickness measurements in OHT patients were significantly higher than those in healthy subjects (575± 30 μ m vs.555± 32 μ m; P=0.002). Higher GDx VCC parameter nerve fiber indicator (NFI) scores, indicating thinner RNFL, were correlated significantly with thinner CCT measurements in OHT patients (r=- 0.502; P=0.001). Ocular hypertension patients with thinner corneas (n=22; mean CCT,553± 21 μ m)- had significantly higher NFI scores than OHT patients with thicker corneas (n=22; mean CCT,598± 18 μ m) and healthy control subjects (NFI mean± standard deviation, 26.9± 9.5, 20.7± 9.8, and 19.7± 7.0, respectively; P=0.004, analysis of variance). The NFI values were not significantly different between OHT patients with thicker corneas and healthy subjects. In multivariate analysis, only age and CCT measurement were associated significantly with GDx VCC RNFL measurements in OHT eyes. Conclusions: Ocular hypertension patients with thinner corneas had significantly thinner RNFL than OHT patients with thicker corneas and healthy control subjects. These findings support the notion thatRNFL defects as assessed by the GDx VCC may represent early glaucomatous damage in OHT eyes.
文摘Purpose.Tumour diameter,tumour height,and tumour volume are considered important pro gnostic indicators of survival in choroidal melanomas.In this study,we inves-tigated the prognostic impact on sur vival of the easily cal-culated volume estimate based on the assumption of a half-rotation ellipsoid.Methods.The largest tumour diam-eter and tumour height were measured by ultrasound A-and B-scan in 93patients with choroidal melanoma.Tumour volume was calculated by the half volume of a rotation el-lipsoid formula,rotated around the y-axis,and compared to tumour diameter and tumour height.A ll parameters were correlated to the clinical outcome o f the patients.Results.At the time of diagnosis,the mean dia meter was 10.4mm(range 4.1-18.9mm),and the mean height was 5.7mm(range 1.74-14.9mm).The range of the calculated tu-mour volume was between 11and 628mm 3 (mean volume 190mm 3 ).Among all patients,distant metastases occurred in 10patients(10.8%).In a univariate approach using Mantel-Haenszel log-rank test,the calculated tumour vol-ume at the time of diagnosis was the best prognostic indicator of survival followed by tu mour diameter and tu-mour height (P=0.028).When tumour volume,hori-zontal and vertical tumour diameter,age,sex,and primary tumour therapy were considered in a multivariate approach using Cox proportional Hazard model,only tumour volume turned out as a significant prognostic parameter(P=0.001).Conclusions.Calculated tumour volume is a bet-ter prognostic indicator of survival of patients with choroidal melanomas than the largest tumour di ameter and tumour height,and might be established in d aily routine.
基金the National Natural Science Foundation of China (No. 59236130).
文摘In this companion paper, flow patterns in the upstream and downstream tubes of a sudden-expansion cross-section (SECS) in a vertical straight pipe were presented. The effect of SECS on flow patterns upstream and downstream was analyzed by comparing with flow patterns in uniform cross-section vertical tubes. It is found the effect is great. There exist great instabilities of two-phase flow in the neighboring areas of the SECS both downstream and upstream.
基金Supported by the National Natural Science Foundation of China(50823002)
文摘In order to achieve uniform mixing between spray droplets and crossflow, cold-model experiment of a hollow-cone water spray in an air crossflow is investigated via a numerical simulation. The simulation cases are designed by using the orthogonal design method. The Eulerian-Lagrangian formulation is employed for modeling the droplets-crossflow two-phase flow while the realizable k-ε turbulence model is used to describe the turbulence. A new index, mixedness quality, is proposed to assess the overall mixing of the droplets in the crossflow. The simulation results demonstrate that the counter-rotating vortex pair (CVP) imposes a more significant impact on the spatial distribution than on the size distribution of the droplets. Pairs of CVP with smaller scales are preferable for achieving a better mixing. The influencing factors are listed in the following order in terms of the degree of their impact from the greatest to the least: the Sauter diameter of the initial droplets, the mixing tube diameter, the spray angle, the velocity of the inlet crossflow, and the vertical velocity of the initial droplets. A moderate droplet diameter, a smaller tube diameter, a moderate spray angle, a greater crossflow velocity and a moderate vertical velocity of the droplet are favorable for achieving a higher mixedness quality of the jet spray in a confined crossflow.
基金the National Natrual Science Foundation of China (No. 59236130).
文摘Flow patterns upstream and downstream of a sudden-contraction cross-section in a vertical straight pipe were presented. By comparing with flow patterns in uniform cross-section vertical tubes, the effect of the sudden change in pipe diameter on flow patterns was analyzed. Flow pattern transition mechanisms were discussed and transition criteria for flow pattern transitions were deduced accordingly using the dimensional analysis.
基金Project(U1134207)supported by the National Natural Science and High Speed Railway Jointed Foundation of ChinaProject(B13024)supported by the "111" Program of China+1 种基金Project(BK2012811)supported by the Nature Science Foundation of Jiangsu Province,ChinaProject(NCET-12-0843)supported by the Fund for New Century Excellent Talents in Universities,China
文摘Considering the viscous damping of the soil and soil-pile vertical coupled vibration,a computational model of large-diameter pipe pile in layered soil was established.The analytical solution in frequency domain was derived by Laplace transformation method.The responses in time domain were obtained by inverse Fourier transformation.The results of the analytical solution proposed agree well with the solutions in homogenous soil.The effects of the shear modulus and damping coefficients of the soil at both outer and inner sides of the pipe pile were researched.The results indicate that the shear modulus of the outer soil has more influence on velocity admittance than the inner soil.The smaller the shear modulus,the larger the amplitude of velocity admittance.The velocity admittance weakened by the damping of the outer soil is more obvious than that weakened by the damping of the inner soil.The displacements of the piles with the same damping coefficients of the outer soil have less difference.Moreover,the effects of the distribution of soil layers are analyzed.The results indicate that the effect of the upper soil layer on dynamic response of the pipe pile is more obvious than that of the bottom soil layer.A larger damping coefficient of the upper layer results in a smaller velocity admittance.The dynamic response of the pipe pile in layered soil is close to that of the pipe pile in homogenous soil when the properties of the upper soil layer are the same.
