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Effects of scleral encircling surgery on vitreous cavity length and diopter
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作者 Zi-Cheng Zhu Gen-Jie Ke +1 位作者 Yue-Chun Wen Zhang-You Wu 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2016年第4期572-574,共3页
AIM: To observe the changes of vitreous cavity length and diopter after scleral encircling(SE) produce.·METHODS: This prospective study included 68 eyes of68 non-consecutive patients with macula-off retinal d... AIM: To observe the changes of vitreous cavity length and diopter after scleral encircling(SE) produce.·METHODS: This prospective study included 68 eyes of68 non-consecutive patients with macula-off retinal detachment who were operated by SE surgery. The corneal refractive power, ocular axial length and diopter were measured by keratometer, A-mode ultrasonic meter and computed dioptometer.· RESULTS: There was no significant difference in corneal refractive power among preoperative and post operative 1, 3 and 6mo(0.57±0.54 D at pre-surgery; 0.72±0.26 D at 1mo; 0.71 ±0.34 D at 3mo; 0.69 ±0.31 D at 6mo;all P 〉0.05). Axial lengths were obviously lengthened,especially in vitreous cavity length(17.87 ±3.09 mm,19.69 ±3.12 mm, 18.97 ±3.56 mm, 18.76 ±3.47 mm, 18.68 ±3.42 mm at pre-surgery, 1wk, 1, 3 and 6mo postoperatively,P 〈0.05) and diopter also increased at beginning and then recovered gradually. After 1 and 3 mo, axial length(vitreous cavity length) and myopia were more and in higher degree than before surgery.·CONCLUSION: The change of postoperative vitreous cavity length is the main factor that results in the changes of axial length and then makes the change of diopter. 展开更多
关键词 sclera encircling vitreous cavity length diopter axial length
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Effect of cavity length detuning on the output characteristics for the middle infrared FEL oscillator of FELiChEM 被引量:2
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作者 赵周宇 李和廷 贾启卡 《Chinese Physics C》 SCIE CAS CSCD 2017年第10期139-144,共6页
FELiChEM is an infrared free electron laser(FEL) facility currently under construction, which consists of two oscillators generating middle-infrared and far-infrared laser covering the spectral range of 2.5–200 μm... FELiChEM is an infrared free electron laser(FEL) facility currently under construction, which consists of two oscillators generating middle-infrared and far-infrared laser covering the spectral range of 2.5–200 μm. In this paper, we numerically study the output characteristics of the middle-infrared oscillator with accurate cavity length detuning. Emphasis is put on the temporal structure of the micropulse and the corresponding spectral bandwidth.Taking the radiation wavelengths of 50 μm and 5 μm as examples, we show that the output pulse duration can be tuned in the range of 1–6 ps with corresponding bandwidth of 13%–0.2% by adjusting the cavity length detuning.In addition, a special discussion on the comb structure is presented, and it is indicated that the comb structure may arise in the output optical pulse when the normalized slippage length is much smaller than unity. This work has reference value for the operation of FELiChEM and other FEL oscillators. 展开更多
关键词 free electron laser oscillator cavity length detuning output characteristics comb structure
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EFFECTS OF HYDRAULIC AND GEOMETRIC PARAMETERS ON DOWNSTREAM CAVITY LENGTH OF DISCHARGE TUNNEL SERVICE GATE 被引量:2
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作者 MOHAGHEGH A 《Journal of Hydrodynamics》 SCIE EI CSCD 2009年第6期774-778,共5页
Aerators on discharge tunnel outlets may be regarded as an effective protection against cavitation erosion. The air entrainment of aerators is governed by a number of independent parameters, including the bottom slope... Aerators on discharge tunnel outlets may be regarded as an effective protection against cavitation erosion. The air entrainment of aerators is governed by a number of independent parameters, including the bottom slope of releasing free-surface flow tunnel downstream of service gate, the end top slope of pressure tunnel, the height of step, and the Froude number at take-off. During eight phases of experiments, the effects of above-mentioned parameters were observed on the cavity length downstream of the fully open operating service gate of a discharge tunnel. The results show that, the bottom slope of releasing free-surface flow tunnel has obvious effect on the cavity length as well as the Froude number at gate take-off. The effect of the step height variations on the cavity length could be considered for higher discharges and steeper tunnel top slope, particularly in higher discharges, resulting in shorter cavity length downstream of service gate. 展开更多
关键词 cavitation erosion cavity length discharge tunnel service gate
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Variation of Lasing Wavelength of Fiber Grating Semiconductor Laser with Temperature for Different External Cavity Lengths
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作者 Zhengmao Wu, Hanqing Zhou, Guangqiong Xia, Department of Physics, Southwest Normal University, Chongqing 400715, P. R. China, Tel: 86-23-68254609 《光学学报》 EI CAS CSCD 北大核心 2003年第S1期519-520,共2页
For different external cavity lengths, lasing wavelength variation of fiber grating external cavity semiconductor laser (FGECSL) with ambient temperature has been investigated theoretically, and the theoretical result... For different external cavity lengths, lasing wavelength variation of fiber grating external cavity semiconductor laser (FGECSL) with ambient temperature has been investigated theoretically, and the theoretical results are in agreement with reported experimental observations. 展开更多
关键词 for on as WDM of Variation of Lasing Wavelength of Fiber Grating Semiconductor Laser with Temperature for Different External cavity lengths with
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Impact frequency variation of self-excited oscillation pulsed supercritical carbon dioxide jets
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作者 SHEN Helian LIU Yong +3 位作者 WEI Jianping QIU Liming LI Haichao DENG Yujie 《Petroleum Exploration and Development》 SCIE 2023年第5期1261-1268,共8页
In order to obtain the impact frequency of resonant coal breaking by self-excited oscillation pulsed supercritical carbon dioxide(SC-CO_(2))jet,large eddy simulation was used to analyze the formation and development p... In order to obtain the impact frequency of resonant coal breaking by self-excited oscillation pulsed supercritical carbon dioxide(SC-CO_(2))jet,large eddy simulation was used to analyze the formation and development process of self-excited oscillation pulsed SC-CO_(2)jet,the variation of jet impact frequency in the nozzle and the free flow field,and the variation of jet impact frequency at different positions in the jet axis and under different cavity lengths.The test device of jet impact frequency was developed,and experiments were performed to verify the conclusions of the numerical simulations.The results show that the frequency of the self-excited oscillation pulsed SC-CO_(2)jet is different in the nozzle and the free flow field.In the nozzle,the frequency generated by the fluid disturbance is the same,and the jet frequency at the exit of the nozzle is consistent with that inside the nozzle.In the free flow field,due to the compressibility of CO_(2),the pressure,velocity and other parameters of SC-CO_(2)jets have obvious fluctuation patterns.This feature causes the impact frequency of the self-excited oscillation pulsed SC-CO_(2)jet to decrease gradually in the axis.Changing the cavity length allows the adjustment of the jet impact frequency in the free flow field by affecting the disturbance frequency of the self-excited oscillation pulsed SC-CO_(2)jet inside the nozzle. 展开更多
关键词 self-excited oscillation plused SC-CO_(2)jet resonant coal-breaking jet impact frequency cavity length
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Analysis of Cavitation Performance of a 2-D Hydrofoil Based on Mixed-iterative Method 被引量:1
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作者 Chao Wang Chunyu Guo Xin Chang Sheng Huang Pusun Cao 《Journal of Marine Science and Application》 2013年第1期52-57,共6页
In order to study cavitation characteristics of a 2-D hydrofoil, the method that combines nonlinear cavitation model and mixed-iteration is used to predict and analyze the cavitation performance of hydrofoils. The cav... In order to study cavitation characteristics of a 2-D hydrofoil, the method that combines nonlinear cavitation model and mixed-iteration is used to predict and analyze the cavitation performance of hydrofoils. The cavitation elements are nonlinearly disposed based on the Green formula and perturbation potential panel method. At the same time, the method that combines cavity shape for fixed cavity length (CSCL) iteration and cavity shape for fixed cavitation number (CSCN) iteration is used to work out the thickness and length of hydrofoil cavitations. Through analysis of calculation results, it can be concluded that the jump of pressure and velocity potentially exist between cavitation end area and non-cavitations area on suction surface when cavitation occurs on hydrofoil. In certain angles of attack, the cavitation number has a negative impact on the length of cavitations. And under the same angle of attack and cavitation number, the bigger the thickness of the hydrofoil, the shorter the cavitations length. 展开更多
关键词 2-D hydrofoil cavitation performance nonlinear theory mixed-iterative method cavity shape for fixed cavitation number (CSCN) cavity shape for fixed cavity length (CSCL)
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Hydraulics of a multiple slit-type energy dissipater 被引量:11
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作者 吴建华 姚莉 +1 位作者 马飞 吴伟伟 《Journal of Hydrodynamics》 SCIE EI CSCD 2014年第1期86-93,共8页
With the constructions of high dam projects in China, the energy dissipation downstream of a dam becomes a serious concern. In this study, a multiple slit-type energy dissipater, with different reduction size slits in... With the constructions of high dam projects in China, the energy dissipation downstream of a dam becomes a serious concern. In this study, a multiple slit-type energy dissipater, with different reduction size slits in the outlet, is developed on the basis of conventional slit-type energy dissipaters, aiming to enhance the energy dissipation through the turbulence and the friction between the different layers of the jet flow and the air entrainment due to the increased surface of the flow to the air. The hydraulic characteristics of the energy dissipater are experimentally investigated by means of three sets of physical models in nine cases, to characterize the geometric parameters with suitable performance. The main concerns are the flow regime, the jet flow trajectory, the energy dissipation, the cavitation characteristics, and the flow choking. The results indicate that the dissipater enjoys a high energy dissipation ratio with suitable hydraulic performance comparing with the conventional slit-type energy dissipaters. 展开更多
关键词 AERATOR cavity length FIN lateral deflector
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EMERGENCE ANGLE OF FLOW OVER AN AERATOR 被引量:5
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作者 WU Jian-hua RUAN Shi-ping 《Journal of Hydrodynamics》 SCIE EI CSCD 2007年第5期601-606,共6页
Aerator is an important device for release works of hydraulic structures with high-speed flow in order to protect them from cavitation damage. This kind of protecting effect is related closely to cavity length below t... Aerator is an important device for release works of hydraulic structures with high-speed flow in order to protect them from cavitation damage. This kind of protecting effect is related closely to cavity length below the aerator, while the cavity length is dominated by the emergence angle over the aerator. Therefore it is crucial to determine this angle accurately. In the present paper the affecting intensities of flow depth and the fluctuating velocity on this angle were analyzed through two introduced parameters. Furthermore, the improved expressions of emergence angle estimation, for both ramp-type and step-type aerators, were presented by means of 68 sets of experimental data from 6 projects based on error theory. The results showed that the present method has higher accuracy than the previously reported methods. 展开更多
关键词 AERATOR cavitation damage cavity length emergence angle flow depth fluctuating velocity
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INFLUENCE OF FILLING WATER ON AIR CONCENTRATION 被引量:4
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作者 WU Jian-hua MA Fei DAI Hui-chao 《Journal of Hydrodynamics》 SCIE EI CSCD 2011年第5期601-606,共6页
The filling water inside the cavity below an aerator occurs for the flow of low Froude number or the small bottom slope of a spillway. The aerator may cease to protect against cavitation damages, and may even act as a... The filling water inside the cavity below an aerator occurs for the flow of low Froude number or the small bottom slope of a spillway. The aerator may cease to protect against cavitation damages, and may even act as a generator of cavitation if it is fully filled by water. The experiments were conducted to investigate the influences of the geometric parameters, and then the filling water on the air concentration. The results show that the filling water, or the net cavity length, is closely related to the plunging jet length for a given aerator, and the air concentration at some section is proportional to the ratio Ln/Lj at a fixed Lj for different geometric parameters of aerators. Secondly, at the same ratio of Ln / Lj, the aerator with a larger height or a larger angle of ramp, or a larger bottom slope, would have a larger plunging jet length, and then a larger net cavity length based on the ratio of Ln / Lj. As a result, the large space of cavity, or the high air concentration of the flow could be obtained although the filling water increases also based on the fact that Lf = Lj - Ln. It is the space of the cavity that is the dominant factor to affect the air concentration of the flow. 展开更多
关键词 AERATOR air concentration filling water jet length net cavity length
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Fin characteristics of aerator devices with lateral deflectors 被引量:3
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作者 吴建华 李丹 +1 位作者 马飞 钱尚托 《Journal of Hydrodynamics》 SCIE EI CSCD 2013年第2期258-263,共6页
The fins will be formed if the lateral deflectors in the side-walls with a bottom aerator device are improperly designed, and the flow regime downstream of the aerator device will be worsened. In this paper, the heigh... The fins will be formed if the lateral deflectors in the side-walls with a bottom aerator device are improperly designed, and the flow regime downstream of the aerator device will be worsened. In this paper, the height and the length of the fins induced by the lateral deflectors are theoretically analyzed along with their influencing factors, and the fin characteristics are experimentally investigated on the basis of the theoretical analysis. It is shown that the intensities of the fins are strongly dependent on the ratio of the lateral cavity length to the bottom cavity length, and other factors, like the working head, the height and the angle of the lateral deflector, the flow Froude number around the aerator device, affect the fins indirectly through the changes of the lateral cavity length. When an aerator device with lateral deflectors is designed, it is crucial to match the above mentioned ratio, and to make the ratio of the two cavity lengths less than 1.0 in order to avoid the generation of the fins. 展开更多
关键词 AERATOR cavity length FIN lateral deflector
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Air concentration distribution in the impact zone of spillway aerator 被引量:1
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作者 Rui-di Bai Fa-xing Zhang +1 位作者 Wei Wang Shan-jun Liu 《Journal of Hydrodynamics》 SCIE EI CSCD 2022年第1期156-161,共6页
The chute aerators separate the flow from the chute bottom,and the violent turbulence is generated after the flow impacts the bottom.Although the chute aerators were widely investigated experimentally,the air concentr... The chute aerators separate the flow from the chute bottom,and the violent turbulence is generated after the flow impacts the bottom.Although the chute aerators were widely investigated experimentally,the air concentration distribution of the lower jet in the impact zone remains to be explored systematically.In the impact zone,it is observed that a portion of the air stays in the rollers instead of traveling with the flow,decreasing the air transportation capacity.Based on extensive tests,a comprehensive formula is developed to compute the air concentration distribution in the impact zone,with results in good agreement with the model tests. 展开更多
关键词 Chute aerator impact zone air concentration cavity length experimental data
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1.06 μm high-power InGaAs/GaAsP quantum well lasers 被引量:2
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作者 Haili Wang Li Zhong +2 位作者 Jida Hou Suping Liu Xiaoyu Ma 《Journal of Semiconductors》 EI CAS CSCD 2017年第11期66-70,共5页
The high power and low internal loss 1.06 μm InGaAs/GaAsP quantum well lasers with asymmetric waveguide structure were designed and fabricated. For a 4000 μm cavity length and 100 μm stripe width device,the maximum... The high power and low internal loss 1.06 μm InGaAs/GaAsP quantum well lasers with asymmetric waveguide structure were designed and fabricated. For a 4000 μm cavity length and 100 μm stripe width device,the maximum output power and conversion efficiency of the device are 7.13 W and 56.4%, respectively. The cavity length dependence of the threshold current density and conversion efficiency have been investigated theoretically and experimentally; the laser diode with 4000 μm cavity length shows better characteristics than that with 3000 and 4500 μm cavity length: the threshold current density is 132.5 A/cm^2, the slope efficiency of 1.00 W/A and the junction temperature of 15.62 K were achieved. 展开更多
关键词 semiconductor laser high power asymmetric waveguide cavity length
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Single-mode GaAs/AlGaAs quantum cascade microlasers
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作者 高瑜 刘俊岐 +6 位作者 刘峰奇 张伟 张全德 刘万峰 李路 王利军 王占国 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2009年第11期55-58,共4页
Single-mode edge emitting GaAs/AlGaAs quantum cascade microlasers at a wavelength of about 11.4μm were realized by shortening the Fabry-Perot cavity length. The spacing of the longitudinal resonator modes is inversel... Single-mode edge emitting GaAs/AlGaAs quantum cascade microlasers at a wavelength of about 11.4μm were realized by shortening the Fabry-Perot cavity length. The spacing of the longitudinal resonator modes is inversely proportional to the cavity length. Stable single-mode emission with a side mode suppression ratio of about 19 dB at 85 K for a 150-μm-long device was demonstrated. 展开更多
关键词 quantum cascade lasers GAAS/ALGAAS single-mode emission short cavity length
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