AIM:To compare the accuracy of manual marking versus an image-guided system for toric implantable collamer lens(TICL)implantation and evaluate the short-term postoperative rotational stability of TICL and corneal surg...AIM:To compare the accuracy of manual marking versus an image-guided system for toric implantable collamer lens(TICL)implantation and evaluate the short-term postoperative rotational stability of TICL and corneal surgically induced astigmatism vector(SIA).METHODS:Retrospective analysis was conducted on eyes with TICL alignment achieved through manual marking(n=75)or VERION image-guided system-assisted marking(n=83).Each group was further classified into horizontal and vertical subgroups based on implant orientation.Additionally,patients were categorized into superior and temporal incision subgroups according to the position of main corneal incision.The misalignment and rotational stability of TICL were analyzed using slit-lamp anterior segment photography.Surgical predictability,efficacy,safety,and corneal SIA were also evaluated.RESULTS:In general,the TICL implantation with manual and digital image-guided systems all achieved robust predictability,efficacy,and safety.The misalignment of TICL was comparable between the manual and VERION groups(0.16°±3.97°vs 0.52°±5.59°,P=0.633),while a significant difference was observed in the absolute misalignment of TICL between the two groups(3.02°±2.55°vs 4.28°±3.61°,P=0.043).There were no significant differences in the distribution of TICL misalignment between the manual and VERION groups or between horizontal and vertical implant orientation groups(P>0.05).Furthermore,different orientations of TICL placement did not show statistically significant differences in rotational stability(P=0.46).Statistically significant differences were found in anterior corneal SIA between the manual and VERION groups(0.46±0.27 vs 0.33±0.21 D,P=0.001),especially for superior incision position(0.60±0.27 vs 0.35±0.23 D,P<0.0001).The anterior SIA exhibited a significant difference between superior and temporal incisions in the manual group(0.60±0.27 vs 0.35±0.20 D,P<0.0001).CONCLUSION:Compared with the conventional manual marking method,this study indicates that the digital image-guided system with VERION is safe and effective in TICL implantation.The digital system offers the advantage of minimizing corneal SIA compared to the manual method.展开更多
The high rolling speed of a missile heavily affects the stabilizing capability of the inertial platform in the laser tracking system （LTS） of the missile. In this paper, a rotational stabilizing platform （RSP） and...The high rolling speed of a missile heavily affects the stabilizing capability of the inertial platform in the laser tracking system （LTS） of the missile. In this paper, a rotational stabilizing platform （RSP） and a fuzzy-PID controller is designed to stabilize the inertial platform. This controller integrates the advantages of both fuzzy controller and classic PID controller. A comparison study is carried out to illustrate the advantages of the proposed fuzzy-PID controller over the classic PID controller. Numerical results indicate that the fuzzy-PID controller outperforms the classic one in effectively handling nonlinear disturbances and quickly stabilizing the inertial platform at the sudden change of missile roiling speed.展开更多
Objective:To analyze the enduring rotational steadiness of AcrySof IQ Toric intraocular lens(IOL)in cataract patients suffering from myopia in a long-term study.Methods:A retrospective study was conducted on a case se...Objective:To analyze the enduring rotational steadiness of AcrySof IQ Toric intraocular lens(IOL)in cataract patients suffering from myopia in a long-term study.Methods:A retrospective study was conducted on a case series involving 78 patients.A total of 120 eyes with an axial length(AL)ranging from 24-30 mm and corneal astigmatism≥1.50 D underwent implantation of AcrySof IQ Toric IOL guided by the version navigation system.The eyes were divided into two groups based on AL.Group A included 60 eyes with high myopia(AL≥26 mm),while Group B consisted of eyes with low to moderate myopia(24 mm≤AL<26 mm).Data on the preoperative AL were collected.Measurements were taken for residual astigmatism,the best corrected visual acuity(BCDVA),corneal astigmatism,and IOL rotation occurring between 24-and 48-months post-surgery.The percentage of eyes with an IOL rotation of under 5°and 10°was analyzed.Results:The mean length of follow-up times was recorded as 34.27±4.98,and the average rotation was 2.73±1.29°.Group A exhibited a slightly higher average rotation of 2.87±1.31°,compared to the rotation of 2.59±1.27°observed in Group B.At both the 24-36 month and 26-48 month post-operation marks,the degree of IOL rotation did not show a statistically significant difference between the two groups,with none of the patients experiencing a rotation exceeding 10°(P>0.05).The percentage of rotation degrees under 5°was recorded as 98.22%.After the procedure,the BCDVA was 0.1322±0.03 LogMAR.There was a substantial increase in theχvalue after the operation as compared to the pre-operativeχ^(2) value(χ^(2)=76.79).The standard deviation of preoperative corneal astigmatism was statistically significant(P<0.05)at 2.17±1.08 D.Following the surgical procedure,the remaining astigmatism was measured at 0.41±0.26 D.The data showed a notable gap in statistical significance(t=4.281,P<0.05).Conclusion:The AcrySof Toric IOL was a reliable solution for managing corneal astigmatism in cataract patients with myopia,demonstrating excellent long-term rotational stability.展开更多
AIM：To evaluate the rotational stability and visual outcomes of a single-piece hydrophilic acrylic toric intraocular lenses（IOL） over a 1.5-year follow-up period.Data from the 6-month follow-up study have been prev...AIM：To evaluate the rotational stability and visual outcomes of a single-piece hydrophilic acrylic toric intraocular lenses（IOL） over a 1.5-year follow-up period.Data from the 6-month follow-up study have been previously reported.METHODS：Forty eyes of 26 cataract patients（mean age：72.8±7.9y） with pre-existing corneal astigmatism of 1.0 to 2.6 D were enrolled in the study.Mean axial length was 23.17±0.88 mm.Main outcome measures after implantation of the Torica-a A IOL（Human Optics） were IOL rotational stability,subjective refraction,astigmatism correction,uncorrected and corrected distance visual acuity（UDVA,CDVA）.RESULTS：There was no significant change in the parameters evaluated between the 6-month and 1.5-year follow-ups.At last visit,mean absolute IOL rotation（objective method） was 1.81°±1.87°（range 0.00° to 7.20°） with 78.6% of eyes having IOL rotation 〈3°,92.9% of eyes 〈5° and 100% of eyes 〈8°.No patient required secondary IOL repositioning during the course of the study.Mean residual refractive cylinder was-0.60±0.40 D.There was a significant reduction in the magnitude of the J0 vector postoperatively（P〈0.0001） with a mean absolute change of 0.76±0.40 D.The mean J45 vector was close to zero preoperatively and postoperatively and didn＇t change significantly（P=0.28）.Mean monocular UDVA and CDVA was 0.09±0.12 log MAR and-0.01±0.12 log MAR,respectively.No treatment with Nd：YAG laser was required.CONCLUSION：The Torica-a A IOL shows good and stable visual performance and rotational stability over a 1.5-year follow-up period.展开更多
AIM: To compare the short-term visual outcomes, residual refractive cylinder, and rotation stability after Tecnis toric intraocular lens(IOL) implantation during femtosecond laserassisted cataract surgery(Femto phaco)...AIM: To compare the short-term visual outcomes, residual refractive cylinder, and rotation stability after Tecnis toric intraocular lens(IOL) implantation during femtosecond laserassisted cataract surgery(Femto phaco) and conventional phacoemulsification surgery(Conventional phaco).METHODS: In a prospective cohort study, Conventional phaco and Femto phaco(anterior capsulotomy and lens fragmentation by a femtosecond laser) with Tecnis toric IOL implantation were performed in 40 eyes from 36 patients and 37 eyes from 33 patients, respectively. The uncorrected distance visual acuity(UDVA), corrected distance visual acuity(CDVA), and manifest refraction were assessed during 1 d, 1 wk, and 1 mo follow-ups. The orientation of the Tecnis Toric IOL was evaluated during 1 wk and 1 mo follow-ups.RESULTS: There were no significant differences in UDCA or CDVA between two groups at 1 mo postoperatively, though relatively more subjects had UDVA values of 20/25 or better in Femto phaco group than in the Conventional group(P>0.05). A lower but not significantly lower rate of having more than 5° of IOL rotation was observed in Femto phaco group at the 1-month follow-up, while a significant lower rate of residual astigmatism of ≤1 D was observed in Femto phaco group.CONCLUSION: The Femto phaco group has significantly more subjects with the residual astigmatism of ≤1 D, but there are no significant differences in rotation stability and visual outcomes as compared with the Conventional phaco group after the application of the Tecnis toric IOL in this cohort.展开更多
Stability analysis of gravity retaining wall was currently based on the assumption that the wall had no embedment depth. The effect of earth berm was usually neglected. The present work highlighted the importance of e...Stability analysis of gravity retaining wall was currently based on the assumption that the wall had no embedment depth. The effect of earth berm was usually neglected. The present work highlighted the importance of embedment depth when assessing the seismic stability of gravity retaining walls with the pattern of pure rotation. In the framework of upper bound theorem of limit analysis, pseudo-static method was applied into two groups of parallel rigid soil slices methods in order to account for the effect of embedment depth on evaluating the critical acceleration of wall-soil system. The present analytical solution is identical to the results obtained from using limit equilibrium method, and the two methods are based on different theory backgrounds. Parameter analysis indicates that the critical acceleration increases slowly when the ratio of the embedment depth to the total height of the wall is from 0 to 0.15 and increases drastically when the ratio exceeds 0.15.展开更多
A stall inception model for transonic fan/compressors is presented in this paper. It can be shown that under some assumptions the solution of unsteady flow field consists of pressure wave which propagates upstream or ...A stall inception model for transonic fan/compressors is presented in this paper. It can be shown that under some assumptions the solution of unsteady flow field consists of pressure wave which propagates upstream or downstream, vortex wave and entropy wave convected with the mean flow speed. By further using the mode-matching technique and applying the conservation law and conditions reflecting the loss characteristics of a compressor in the inlet and outlet of the rotor or stator blade rows, a group of homogeneous equations can be obtained from which the stability equation can be derived. Based on the analysis of the unsteady phenomenon caused by casing treatments, the function of casing treatments has been modeled by a wall impedance condition which has been included in the stability model through the eigenvalues and the corresponding eigenfunctions of the system. Besides, the effect of shock waves in cascade channel on the stability prediction is also considered in the stall inception model. Finally, some numerical analysis and experimental investigation are also conducted with emphasis on the mutual comparison.展开更多
AIM:To evaluate the postoperative intraocular lens(IOL)rotational stability and residual refractive astigmatism following combined 25-gauge vitrectomy and cataract surgery with implantation of a plate haptic toric IOL...AIM:To evaluate the postoperative intraocular lens(IOL)rotational stability and residual refractive astigmatism following combined 25-gauge vitrectomy and cataract surgery with implantation of a plate haptic toric IOL.METHODS:In this retrospective case series,32 eyes of 32 patients underwent a combined 25-gauge vitrectomy and phacoemulsification for vitreoretinal diseases and cataract with regular corneal astigmatism of at least 1 diopter(D).A plate haptic toric IOL(AT Torbi 709M,Carl Zeiss Meditec AG)was implanted in all eyes.The outcome measures were rotational stability and refractive astigmatism up to 6mo postoperatively as well as the best corrected visual acuity(BCVA).RESULTS:Preoperative refractive astigmatism was 2.14±1.17 D,which was significantly reduced to 0.77±0.37 D six to eight weeks postoperatively and remained stable throughout the observation period(0.67±0.44 D at three months and 0.75±0.25 D at six months;for all groups:P<0.0001 compared to baseline).BCVA improved significantly from 0.36±0.33 logMAR preoperatively to 0.10±0.15 logMAR following surgery(P=0.02).Mean IOL axis deviation from the target axis was 3.4°±2.9°after six to eight weeks and significantly decreased over time(2.4°±2.6°six months after surgery;P=0.04).In one patient IOL,re-alignment was performed.CONCLUSION:Corneal astigmatism is significantly reduced following combined 25-gauge vitrectomy and cataract surgery.The plate haptic toric IOL position and axis remain stable during the observation period of six months.展开更多
Generally, casing treatment（CT） is a passivity method to enhance the stall margin of fan/compressor. A novel casing treatment based on the small disturbance theory and vortex and wave interaction suggestion is a met...Generally, casing treatment（CT） is a passivity method to enhance the stall margin of fan/compressor. A novel casing treatment based on the small disturbance theory and vortex and wave interaction suggestion is a method combining passive control and active control, which has been proved effective at enhancing the stall margin of fan/compressor in experiment. In order to investigate the mechanism of this kind of casing treatment, an experimental investigation of a stall precursor-suppressed（SPS） casing treatment with air suction or blowing air is conducted in the present paper. The SPS casing treatment is designed to suppressing stall precursors to realize stall margin enhancement in turbomachinery. The experimental results show that the casing treatment with blowing air of small quantity can improve the stall margin by about 8% with about 1% efficiency loss. By contrast, the SPS casing treatment with micro-bias flow does not improve the stall margin much more than that without bias flow, even worse. Meanwhile, the present investigation has also attempted to reveal the mechanism of stall margin improvement with the casing treatment.It is found that the stall margin improvements vary with the modification of the unsteady shedding flow and the unsteady wall boundary impedance. The experimental results agree fairly well with the theoretical prediction using a flow stability model of rotating stall.展开更多
In order to investigate the effects of probe support on the stall characteristics of micro compressors, an experiment was carried out on a large-scale low-speed research compressor according to the principle of geomet...In order to investigate the effects of probe support on the stall characteristics of micro compressors, an experiment was carried out on a large-scale low-speed research compressor according to the principle of geometric similarity. A cylindrical probe support intruding to 50% blade span was mounted at 50% chord upstream from the rotor blade leading edge. The static pressure rise characteristic of the compressor is measured, with and without the probe support respectively. The dynamic compressor behavior from pre-stall to full stall was also measured. The results indicate that the stability margin of the compressor is lowered after installing the probe support. The stall inception is aroused by modal wave disturbances. The disturbances developed into two stall cells smoothly before installing the probe support, while the disturbances first developed into a single stall cell then splitting into two stall cells after installing the probe support. The presence of probe support lowers the initial intensity of the rotating stall of the compressor, while it doesn't alter the intensity of the rotation stall after the compressor enters into full stall.展开更多
文摘AIM:To compare the accuracy of manual marking versus an image-guided system for toric implantable collamer lens(TICL)implantation and evaluate the short-term postoperative rotational stability of TICL and corneal surgically induced astigmatism vector(SIA).METHODS:Retrospective analysis was conducted on eyes with TICL alignment achieved through manual marking(n=75)or VERION image-guided system-assisted marking(n=83).Each group was further classified into horizontal and vertical subgroups based on implant orientation.Additionally,patients were categorized into superior and temporal incision subgroups according to the position of main corneal incision.The misalignment and rotational stability of TICL were analyzed using slit-lamp anterior segment photography.Surgical predictability,efficacy,safety,and corneal SIA were also evaluated.RESULTS:In general,the TICL implantation with manual and digital image-guided systems all achieved robust predictability,efficacy,and safety.The misalignment of TICL was comparable between the manual and VERION groups(0.16°±3.97°vs 0.52°±5.59°,P=0.633),while a significant difference was observed in the absolute misalignment of TICL between the two groups(3.02°±2.55°vs 4.28°±3.61°,P=0.043).There were no significant differences in the distribution of TICL misalignment between the manual and VERION groups or between horizontal and vertical implant orientation groups(P>0.05).Furthermore,different orientations of TICL placement did not show statistically significant differences in rotational stability(P=0.46).Statistically significant differences were found in anterior corneal SIA between the manual and VERION groups(0.46±0.27 vs 0.33±0.21 D,P=0.001),especially for superior incision position(0.60±0.27 vs 0.35±0.23 D,P<0.0001).The anterior SIA exhibited a significant difference between superior and temporal incisions in the manual group(0.60±0.27 vs 0.35±0.20 D,P<0.0001).CONCLUSION:Compared with the conventional manual marking method,this study indicates that the digital image-guided system with VERION is safe and effective in TICL implantation.The digital system offers the advantage of minimizing corneal SIA compared to the manual method.
基金the China Aerospace Science and Innovation Foundation(No. 06CASC0407)
文摘The high rolling speed of a missile heavily affects the stabilizing capability of the inertial platform in the laser tracking system （LTS） of the missile. In this paper, a rotational stabilizing platform （RSP） and a fuzzy-PID controller is designed to stabilize the inertial platform. This controller integrates the advantages of both fuzzy controller and classic PID controller. A comparison study is carried out to illustrate the advantages of the proposed fuzzy-PID controller over the classic PID controller. Numerical results indicate that the fuzzy-PID controller outperforms the classic one in effectively handling nonlinear disturbances and quickly stabilizing the inertial platform at the sudden change of missile roiling speed.
基金This study was funded by a research grant from Alcon(IIT#68022037)Subject of Medical and Health Research in Heilongjiang Province(20230707020332).
文摘Objective:To analyze the enduring rotational steadiness of AcrySof IQ Toric intraocular lens(IOL)in cataract patients suffering from myopia in a long-term study.Methods:A retrospective study was conducted on a case series involving 78 patients.A total of 120 eyes with an axial length(AL)ranging from 24-30 mm and corneal astigmatism≥1.50 D underwent implantation of AcrySof IQ Toric IOL guided by the version navigation system.The eyes were divided into two groups based on AL.Group A included 60 eyes with high myopia(AL≥26 mm),while Group B consisted of eyes with low to moderate myopia(24 mm≤AL<26 mm).Data on the preoperative AL were collected.Measurements were taken for residual astigmatism,the best corrected visual acuity(BCDVA),corneal astigmatism,and IOL rotation occurring between 24-and 48-months post-surgery.The percentage of eyes with an IOL rotation of under 5°and 10°was analyzed.Results:The mean length of follow-up times was recorded as 34.27±4.98,and the average rotation was 2.73±1.29°.Group A exhibited a slightly higher average rotation of 2.87±1.31°,compared to the rotation of 2.59±1.27°observed in Group B.At both the 24-36 month and 26-48 month post-operation marks,the degree of IOL rotation did not show a statistically significant difference between the two groups,with none of the patients experiencing a rotation exceeding 10°(P>0.05).The percentage of rotation degrees under 5°was recorded as 98.22%.After the procedure,the BCDVA was 0.1322±0.03 LogMAR.There was a substantial increase in theχvalue after the operation as compared to the pre-operativeχ^(2) value(χ^(2)=76.79).The standard deviation of preoperative corneal astigmatism was statistically significant(P<0.05)at 2.17±1.08 D.Following the surgical procedure,the remaining astigmatism was measured at 0.41±0.26 D.The data showed a notable gap in statistical significance(t=4.281,P<0.05).Conclusion:The AcrySof Toric IOL was a reliable solution for managing corneal astigmatism in cataract patients with myopia,demonstrating excellent long-term rotational stability.
文摘AIM：To evaluate the rotational stability and visual outcomes of a single-piece hydrophilic acrylic toric intraocular lenses（IOL） over a 1.5-year follow-up period.Data from the 6-month follow-up study have been previously reported.METHODS：Forty eyes of 26 cataract patients（mean age：72.8±7.9y） with pre-existing corneal astigmatism of 1.0 to 2.6 D were enrolled in the study.Mean axial length was 23.17±0.88 mm.Main outcome measures after implantation of the Torica-a A IOL（Human Optics） were IOL rotational stability,subjective refraction,astigmatism correction,uncorrected and corrected distance visual acuity（UDVA,CDVA）.RESULTS：There was no significant change in the parameters evaluated between the 6-month and 1.5-year follow-ups.At last visit,mean absolute IOL rotation（objective method） was 1.81°±1.87°（range 0.00° to 7.20°） with 78.6% of eyes having IOL rotation 〈3°,92.9% of eyes 〈5° and 100% of eyes 〈8°.No patient required secondary IOL repositioning during the course of the study.Mean residual refractive cylinder was-0.60±0.40 D.There was a significant reduction in the magnitude of the J0 vector postoperatively（P〈0.0001） with a mean absolute change of 0.76±0.40 D.The mean J45 vector was close to zero preoperatively and postoperatively and didn＇t change significantly（P=0.28）.Mean monocular UDVA and CDVA was 0.09±0.12 log MAR and-0.01±0.12 log MAR,respectively.No treatment with Nd：YAG laser was required.CONCLUSION：The Torica-a A IOL shows good and stable visual performance and rotational stability over a 1.5-year follow-up period.
基金Supported by Zhejiang Province Key Research and Development Program(No.2015C03042)
文摘AIM: To compare the short-term visual outcomes, residual refractive cylinder, and rotation stability after Tecnis toric intraocular lens(IOL) implantation during femtosecond laserassisted cataract surgery(Femto phaco) and conventional phacoemulsification surgery(Conventional phaco).METHODS: In a prospective cohort study, Conventional phaco and Femto phaco(anterior capsulotomy and lens fragmentation by a femtosecond laser) with Tecnis toric IOL implantation were performed in 40 eyes from 36 patients and 37 eyes from 33 patients, respectively. The uncorrected distance visual acuity(UDVA), corrected distance visual acuity(CDVA), and manifest refraction were assessed during 1 d, 1 wk, and 1 mo follow-ups. The orientation of the Tecnis Toric IOL was evaluated during 1 wk and 1 mo follow-ups.RESULTS: There were no significant differences in UDCA or CDVA between two groups at 1 mo postoperatively, though relatively more subjects had UDVA values of 20/25 or better in Femto phaco group than in the Conventional group(P>0.05). A lower but not significantly lower rate of having more than 5° of IOL rotation was observed in Femto phaco group at the 1-month follow-up, while a significant lower rate of residual astigmatism of ≤1 D was observed in Femto phaco group.CONCLUSION: The Femto phaco group has significantly more subjects with the residual astigmatism of ≤1 D, but there are no significant differences in rotation stability and visual outcomes as compared with the Conventional phaco group after the application of the Tecnis toric IOL in this cohort.
基金Project(41472245)supported by the National Natural Science Foundation of ChinaProject(CQGT-KJ-2014049)supported by the Chongqing Administration of Land,Resources and Housing,ChinaProject(106112014CDJZR200009)supported by the Fundamental Research Funds for the Central Universities,China
文摘Stability analysis of gravity retaining wall was currently based on the assumption that the wall had no embedment depth. The effect of earth berm was usually neglected. The present work highlighted the importance of embedment depth when assessing the seismic stability of gravity retaining walls with the pattern of pure rotation. In the framework of upper bound theorem of limit analysis, pseudo-static method was applied into two groups of parallel rigid soil slices methods in order to account for the effect of embedment depth on evaluating the critical acceleration of wall-soil system. The present analytical solution is identical to the results obtained from using limit equilibrium method, and the two methods are based on different theory backgrounds. Parameter analysis indicates that the critical acceleration increases slowly when the ratio of the embedment depth to the total height of the wall is from 0 to 0.15 and increases drastically when the ratio exceeds 0.15.
基金National Natural Science Foundation of China (50736007, 51010007)
文摘A stall inception model for transonic fan/compressors is presented in this paper. It can be shown that under some assumptions the solution of unsteady flow field consists of pressure wave which propagates upstream or downstream, vortex wave and entropy wave convected with the mean flow speed. By further using the mode-matching technique and applying the conservation law and conditions reflecting the loss characteristics of a compressor in the inlet and outlet of the rotor or stator blade rows, a group of homogeneous equations can be obtained from which the stability equation can be derived. Based on the analysis of the unsteady phenomenon caused by casing treatments, the function of casing treatments has been modeled by a wall impedance condition which has been included in the stability model through the eigenvalues and the corresponding eigenfunctions of the system. Besides, the effect of shock waves in cascade channel on the stability prediction is also considered in the stall inception model. Finally, some numerical analysis and experimental investigation are also conducted with emphasis on the mutual comparison.
文摘AIM:To evaluate the postoperative intraocular lens(IOL)rotational stability and residual refractive astigmatism following combined 25-gauge vitrectomy and cataract surgery with implantation of a plate haptic toric IOL.METHODS:In this retrospective case series,32 eyes of 32 patients underwent a combined 25-gauge vitrectomy and phacoemulsification for vitreoretinal diseases and cataract with regular corneal astigmatism of at least 1 diopter(D).A plate haptic toric IOL(AT Torbi 709M,Carl Zeiss Meditec AG)was implanted in all eyes.The outcome measures were rotational stability and refractive astigmatism up to 6mo postoperatively as well as the best corrected visual acuity(BCVA).RESULTS:Preoperative refractive astigmatism was 2.14±1.17 D,which was significantly reduced to 0.77±0.37 D six to eight weeks postoperatively and remained stable throughout the observation period(0.67±0.44 D at three months and 0.75±0.25 D at six months;for all groups:P<0.0001 compared to baseline).BCVA improved significantly from 0.36±0.33 logMAR preoperatively to 0.10±0.15 logMAR following surgery(P=0.02).Mean IOL axis deviation from the target axis was 3.4°±2.9°after six to eight weeks and significantly decreased over time(2.4°±2.6°six months after surgery;P=0.04).In one patient IOL,re-alignment was performed.CONCLUSION:Corneal astigmatism is significantly reduced following combined 25-gauge vitrectomy and cataract surgery.The plate haptic toric IOL position and axis remain stable during the observation period of six months.
基金supported by National Natural Science Foundation of China (Nos. 51236001, 51406229 and 51106154)National Basic Research Program of China (No. 2012CB720201)+1 种基金Aeronautical Science Foundation of China (No. 2014ZB51018)Fundamental Research Funds for the Central Universities
文摘Generally, casing treatment（CT） is a passivity method to enhance the stall margin of fan/compressor. A novel casing treatment based on the small disturbance theory and vortex and wave interaction suggestion is a method combining passive control and active control, which has been proved effective at enhancing the stall margin of fan/compressor in experiment. In order to investigate the mechanism of this kind of casing treatment, an experimental investigation of a stall precursor-suppressed（SPS） casing treatment with air suction or blowing air is conducted in the present paper. The SPS casing treatment is designed to suppressing stall precursors to realize stall margin enhancement in turbomachinery. The experimental results show that the casing treatment with blowing air of small quantity can improve the stall margin by about 8% with about 1% efficiency loss. By contrast, the SPS casing treatment with micro-bias flow does not improve the stall margin much more than that without bias flow, even worse. Meanwhile, the present investigation has also attempted to reveal the mechanism of stall margin improvement with the casing treatment.It is found that the stall margin improvements vary with the modification of the unsteady shedding flow and the unsteady wall boundary impedance. The experimental results agree fairly well with the theoretical prediction using a flow stability model of rotating stall.
基金funded by the National Natural Science Foundation of China(Grant No.51161130525 and 51136003)the 111 Project,No.B07009
文摘In order to investigate the effects of probe support on the stall characteristics of micro compressors, an experiment was carried out on a large-scale low-speed research compressor according to the principle of geometric similarity. A cylindrical probe support intruding to 50% blade span was mounted at 50% chord upstream from the rotor blade leading edge. The static pressure rise characteristic of the compressor is measured, with and without the probe support respectively. The dynamic compressor behavior from pre-stall to full stall was also measured. The results indicate that the stability margin of the compressor is lowered after installing the probe support. The stall inception is aroused by modal wave disturbances. The disturbances developed into two stall cells smoothly before installing the probe support, while the disturbances first developed into a single stall cell then splitting into two stall cells after installing the probe support. The presence of probe support lowers the initial intensity of the rotating stall of the compressor, while it doesn't alter the intensity of the rotation stall after the compressor enters into full stall.
