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Application of oblique photogrammetry technique in geological hazard identification and decision management
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作者 Min Tang Xi Mei +3 位作者 Yanna Li Chen Chen Xiuju Liu Heng Lu 《Earthquake Research Advances》 CSCD 2024年第3期34-41,共8页
With the continuous development of the oblique photography technique, it has been used more and more widely in the field of geological disasters. It can quickly obtain the three-dimensional(3D) real scene model of dan... With the continuous development of the oblique photography technique, it has been used more and more widely in the field of geological disasters. It can quickly obtain the three-dimensional(3D) real scene model of dangerous mountainous areas under the premise of ensuring the safety of personnel while restoring the real geographic information as much as possible. However, geological disaster areas are often accompanied by many adverse factors such as cliffs and dense vegetation. Based on this, the paper introduced the flight line design of oblique photogrammetry, analyzed the multi-platform data fusion processing, studied the multi-period data dynamic evaluation technology and proposed the application methods of data acquisition, early warning, disaster assessment and decision management suitable for geological disaster identification through the analysis of actual cases, which will help geologists to plan and control geological work more scientifically and rationally, improve work efficiency and reduce the potential personnel safety hazards in the process of geological survey, to offer technical support to the application of oblique photogrammetry in geological disaster identification and decision making and provide the scientific basis for personal and property safety protection and later-stage geological disaster management in disaster areas. 展开更多
关键词 oblique photography technique Three-dimensional models Geological hazards Data integration Disaster assessment Decision management
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Exploring mechanism of hidden,steep obliquely inclined bedding landslides using a 3DEC model:A case study of the Shanyang landslide in Shaanxi Province,China
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作者 Jia-yun Wang Zi-long Wu +3 位作者 Xiao-ya Shi Long-wei Yang Rui-ping Liu Na Lu 《China Geology》 CAS CSCD 2024年第2期303-314,I0001-I0003,共15页
Catastrophic geological disasters frequently occur on slopes with obliquely inclined bedding structures(also referred to as obliquely inclined bedding slopes),where the apparent dip sliding is not readily visible.This... Catastrophic geological disasters frequently occur on slopes with obliquely inclined bedding structures(also referred to as obliquely inclined bedding slopes),where the apparent dip sliding is not readily visible.This phenomenon has become a focal point in landslide research.Yet,there is a lack of studies on the failure modes and mechanisms of hidden,steep obliquely inclined bedding slopes.This study investigated the Shanyang landslide in Shaanxi Province,China.Using field investigations,laboratory tests of geotechnical parameters,and the 3DEC software,this study developed a numerical model of the landslide to analyze the failure process of such slopes.The findings indicate that the Shanyang landslide primarily crept along a weak interlayer under the action of gravity.The landslide,initially following a dip angle with the support of a stable inclined rock mass,shifted direction under the influence of argillization in the weak interlayer,moving towards the apparent dip angle.The slide resistance effect of the karstic dissolution zone was increasingly significant during this process,with lateral friction being the primary resistance force.A reduction in the lateral friction due to karstic dissolution made the apparent dip sliding characteristics of the Shanyang landslide more pronounced.Notably,deformations such as bending and uplift at the slope’s foot suggest that the main slide resistance shifts from lateral friction within the karstic dissolution zone to the slope foot’s resistance force,leading to the eventual buckling failure of the landslide.This study unveils a novel failure mode of apparent dip creep-buckling in the Shanyang landslide,highlighting the critical role of lateral friction from the karstic dissolution zone in its failure mechanism.These insights offer a valuable reference for mitigating risks and preventing disasters related to obliquely inclined bedding landslides. 展开更多
关键词 LANDSLIDE Steep obliquely inclined bedding slope Failure mode Failure mechanism Apparent dip creep-buckling Lateral friction 3DEC model Landslide numerical model Geological hazards survey engineering
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Factors that influence the results of indirect decompression employing oblique lumbar interbody fusion
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作者 Andrey E Bokov Svetlana Y Kalinina +2 位作者 Mingiyan I Khaltyrov Alexandr P Saifullin Anatoliy A Bulkin 《World Journal of Orthopedics》 2024年第8期734-743,共10页
BACKGROUND Indirect decompression is one of the potential benefits of anterior reconstruction in patients with spinal stenosis.On the other hand,the reported rate of revision surgery after indirect decompression highl... BACKGROUND Indirect decompression is one of the potential benefits of anterior reconstruction in patients with spinal stenosis.On the other hand,the reported rate of revision surgery after indirect decompression highlights the necessity of working out prediction models for the radiographic results of indirect decompression with assessing their clinical relevance.AIM To assess factors that influence radiographic and clinical results of the indirect decompression in patients with stenosis of the lumbar spine.METHODS This study is a single-center cross-sectional evaluation of 80 consecutive patients(17 males and 63 females)with lumbar spinal stenosis combined with the instability of the lumbar spinal segment.Patients underwent single level or bisegmental spinal instrumentation employing oblique lumbar interbody fusion(OLIF)with percutaneous pedicle screw fixation.Radiographic results of the indirect decompression were assessed using computerized tomography,while MacNab scale was used to assess clinical results.RESULTS After indirect decompression employing anterior reconstruction using OLIF,the statistically significant increase in the disc space height,vertebral canal square,right and left lateral canal depth were detected(Р<0.0001).The median(M)relative vertebral canal square increase came toМ=24.5%with 25%-75%quartile border(16.3%;33.3%)if indirect decompression was achieved by restoration of the segment height.In patients with the reduction of the upper vertebrae slip,the median of the relative increase in vertebral canal square accounted for 49.5%with 25%-75%quartile border(2.35;99.75).Six out of 80 patients(7.5%)presented with unsatisfactory results because of residual nerve root compression.The critical values for lateral recess depth and vertebral canal square that were associated with indirect decompression failure were 3 mm and 80 mm2 respectively.CONCLUSION Indirect decompression employing anterior reconstruction is achieved by the increase in disc height along the posterior boarder and reduction of the slipped vertebrae in patients with degenerative spondylolisthesis.Vertebral canal square below 80 mm2 and lateral recess depth less than 3 mm are associated with indirect decompression failures that require direct microsurgical decompression. 展开更多
关键词 Indirect decompression Anterior reconstruction Central lumbar spinal stenosis Degenerative spondylolisthesis Lateral recess stenosis Spinal instability oblique lateral interbody fusion
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Modified inferior oblique anterior transposition for dissociated vertical deviation combined with superior oblique palsy:A case report
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作者 Yao Zong Ze Wang +1 位作者 Wen-Lan Jiang Xian Yang 《World Journal of Clinical Cases》 SCIE 2023年第12期2796-2802,共7页
BACKGROUND Inferior oblique anterior transposition(IOAT)has emerged as an effective surgery in the management of dissociated vertical deviation(DVD)combined with superior oblique palsy(SOP).Traditional IOAT usually pr... BACKGROUND Inferior oblique anterior transposition(IOAT)has emerged as an effective surgery in the management of dissociated vertical deviation(DVD)combined with superior oblique palsy(SOP).Traditional IOAT usually provides satisfactory primary position alignment and simultaneously restricts the superior floating phenomenon.However,it also increases the risk of the anti-elevation syndrome and narrowing of the palpebral fissure in straight-ahead gaze,especially after the unilateral operation.CASE SUMMARY We report the outcomes of the modified unilateral IOAT in two patients with unilateral DVD combined with SOP.The anterior-nasal fibers of the inferior oblique muscle were attached at 9 mm posterior to the corneal limbus along the temporal board of the inferior rectus muscle,the other fibers were attached a further 5 mm temporal to the anterior-nasal fibers.Postoperatively,both hypertropia and floating were improved,and no obvious complications occurred.CONCLUSION In these cases,the modified unilateral IOAT was an effective and safe surgical method for treating DVD with SOP. 展开更多
关键词 Anterior transposition Inferior oblique muscles Dissociated vertical deviation Superior oblique palsy Anti-elevation syndrome Case report
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Effectiveness of modified inferior oblique muscle belly transposition for V-pattern exotropia combined with mild to moderate inferior oblique muscle overaction
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作者 Yang Hao Ming Zhang +2 位作者 Yue Bian Jing-Ming Li Li Qin 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2023年第3期396-401,共6页
AIM:To investigate the effectiveness of a modified inferior oblique muscle belly transposition for treatment of V-pattern exotropia combined with mild to moderate inferior oblique muscle overaction.METHODS:Thirteen ca... AIM:To investigate the effectiveness of a modified inferior oblique muscle belly transposition for treatment of V-pattern exotropia combined with mild to moderate inferior oblique muscle overaction.METHODS:Thirteen cases(23 affected eyes)of V-pattern exotropia with inferior oblique muscle overaction(+or++)who underwent the modified inferior oblique muscle belly transposition procedure were retrospectively reviewed.The amount of V-pattern,grade of inferior oblique overaction,degree of vertical strabismus,abnormal head posture,and the fovea-disc angle were evaluated before and after surgery.RESULTS:The V-pattern was corrected in all cases,and the amount of V-pattern reduced by 17.85±5.13 prism diopter(PD)on average(t=16.07,P<0.001).The surgical cure rate for mild to moderate inferior oblique muscle overaction was 87.0%(20/23).The degree of the foveadisc angle has a mean reduction of 5.45°±2.87°(t=3.95,P=0.003)after surgery.The mean vertical deviation in 5 cases with a small-angle hypertropia(5.23±3.06 PD)in the primary position reduced by 3.15±1.86 PD(t=6.10,P<0.001).No serious complications were observed.CONCLUSION:The modified inferior oblique muscle belly transposition procedure can effectively treat mild to moderate inferior oblique overaction and relieve the V-pattern,which is safe and easy to perform. 展开更多
关键词 inferior oblique muscle belly transposition V-pattern exotropia inferior oblique muscle overaction
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Architectural Model of a Dryland Gravel Braided River,based on 3D UAV Oblique Photogrammetric Data:A Case Study of West Dalongkou River in Eastern Xinjiang,China 被引量:1
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作者 YIN Senlin ZHU Baiyu +5 位作者 GUO Haiping XU Zhenhua LI Xiaoshan WU Xiaojun CHEN Yukun JIANG Zhibin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2023年第1期269-285,共17页
Three-dimensional unmanned aerial vehicle(UAV)oblique photogrammetric data were used to infer mountainous gravel braided river lithofacies,lithofacies associations and architectural elements.Hierarchical architecture ... Three-dimensional unmanned aerial vehicle(UAV)oblique photogrammetric data were used to infer mountainous gravel braided river lithofacies,lithofacies associations and architectural elements.Hierarchical architecture and lithofacies associations with detailed lithofacies characterizations were comprehensively described to document the architectural model,architectural element scale and gravel particle scale.(1)Nine lithofacies(i.e.,Gmm,Gcm,Gcc,Gci,Gcl,Ss,Sm,Fsm and Fl)were identified and classified as gravel,sand and fine matrix deposits.These are typical depositional features of a mountainous dryland gravel-braided river.(2)Three architectural elements were identified,including channel(CH),gravel bar(GB)and overbank(OB).CH can be further divided into flow channel and abandoned channel,while GB consists of Central Gravel bar(CGB)and Margin Gravel bar(MGB).(3)The gravel bar is the key architectural element of the gravel braided river,with its geological attributes.The dimensions of GBs and their particles are various,but exhibit good relationships with each other.The grain size of GB decreases downstream,but the dimensions of GB do not.The bank erosion affects the GB dimensions,whereas channel incision and water flow velocity influence the grain size of GB.The conclusions can be applied to the dryland gravel braided river studies in tectonically active areas. 展开更多
关键词 three-dimensional UAV oblique photogrammetry gravel braided river architecture modern deposits West Dalongkou River
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Numerical Analysis of the Tunnel-Train-Air Interaction Problem in a Tunnel with a Double-Hat Oblique Hood 被引量:1
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作者 Zongfa Zhang Minglu Zhang Xinbiao Xiao 《Fluid Dynamics & Materials Processing》 EI 2023年第2期345-359,共15页
The tunnel-train-air interaction problem is investigated by using a numerical method able to provide relevant information about pressure fluctuations,aerodynamic drag characteristics and the“piston wind”effect.The m... The tunnel-train-air interaction problem is investigated by using a numerical method able to provide relevant information about pressure fluctuations,aerodynamic drag characteristics and the“piston wind”effect.The method relies on a RNG k-εtwo-equation turbulence model.It is shown that although reducing the oblique slope can alleviate the pressure gradient resulting from initial compression waves at the tunnel entrance,the pressure fluctuations in the tunnel are barely affected;however,a large reduction of micro-pressure wave amplitudes is found outside the tunnel.In comparison to the case where no tunnel hood is present,the amplitudes of micro-pressure waves at 40 m from the tunnel reach an acceptable range.The aerodynamic drag of the head and tail fluctuates greatly while that of the intermediate region undergoes only limited variations when the high-speed train passes through the double-hat oblique tunnel.It is shown that the effects of the oblique slope of the portal on the aerodynamic drag can almost be ignored while the train speed plays an important role. 展开更多
关键词 Double-hat oblique slope micro-pressure wave initial compression wave aerodynamic drag
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Retrospective Case Series of Porous Titanium Cages in Oblique Lumbar Interbody Fusion Surgery Assessing Subsidence, Fusion and Functional Outcomes
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作者 Joseph Maalouly Raghad Barri John Choi 《Open Journal of Orthopedics》 2023年第4期147-156,共10页
Purpose: Implant subsidence is a possible complication of spinal interbody fusion. We aim to evaluate porous titanium cages subsidence, fusion and functional outcomes in patients subjected to oblique lumbar interbody ... Purpose: Implant subsidence is a possible complication of spinal interbody fusion. We aim to evaluate porous titanium cages subsidence, fusion and functional outcomes in patients subjected to oblique lumbar interbody fusion (OLIF) with these novel devices. Methods: Our institutional review board approved a single-center experience which included 60 patients who underwent OLIF from June 2018 to June 2020 utilizing the porous titanium implants. Data was collected in accordance with the Declaration of Helsinki, and written informed consent was obtained. Imaging studies including radiographs 1, 3, 6 and 12 months and computed tomography (CT) scan at 6 months obtained during routine postoperative follow-up visits, were studied for signs of implant subsidence, fusion and clinical parameters to determine the effectiveness of surgery such as Oswestry disability index (ODI). Results: Radiographic subsidence occurred in 1 out of 89 porous titanium interbody cages (1.1%). No subsidence was observed in the posterior screws and rods fixation group (N = 57). However, one case of subsidence occurred in the lateral plate fixation group (N = 3). The subsidence occurred in an osteoporotic elderly patient operated for adjacent segment disease, and she was later revised with posterior instrumentation using cemented screws and rods. She had an uneventful recovery. Fusion rates were evaluated under CT scan at 6 months with a rate of 88%. In terms of clinical outcomes, ODI decreased significantly from 20.3 preop to 10.7 postop with a P-value Conclusions: In our study, the subsidence rate was lower than previously reported in the literature. Also, we had good fusion rates at 6 months likely due to the porous titanium cages use. We had no subsidence in the posterior instrumented group and one case in the lateral fixation group with improved clinical outcomes. 展开更多
关键词 Degenerative Diseases OSTEOARTHRITIS Lumbar Spine Anterior-to-Psoas oblique Lumbar Interbody Fusion
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Treatment of Single Level Lumbar Spondylolisthesis with Lumbar Interbody Fusion via Oblique Lateral Approach (OLIF)
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作者 Jinpeng Zheng Dun Liu +3 位作者 Jing Shi Han Wu Ping Cao Bing Hu 《Surgical Science》 2023年第1期46-54,共9页
Objectives: To investigate the effect of lumbar interbody fusion via the oblique lateral approach (OLIF) in the treatment of single level lumbar spondylolisthesis. Methods: Retrospective analysis was made on 32 cases ... Objectives: To investigate the effect of lumbar interbody fusion via the oblique lateral approach (OLIF) in the treatment of single level lumbar spondylolisthesis. Methods: Retrospective analysis was made on 32 cases of single level lumbar spondylolisthesis treated by lumbar interbody fusion via the oblique lateral approach from July 2020 to July 2021. 14 males and 18 females;the age was (66.5 ± 11.5) years (55 - 82 years). 1) The operation time, intraoperative blood loss and complications were recorded;2) the scores of visual analog scale. VAS and Oswestry disability index (ODI) of low back pain and lower limb pain were collected before operation and at the last follow-up;by observing the imaging data, the height of the intervertebral space, the anterior convex angle of the intervertebral space, the anterior convex angle of the lumbar spine, the sagittal diameter of the dural sac and the spondylolisthesis were measured. Results: All patients successfully completed the operation, the average operation time was (103.9 ± 21.1) min, the average intraoperative bleeding volume was (72.3 ± 16.4) ml. There was no vascular injury during the operation, no infection occurred in all surgical incisions, and Class I/A healing was achieved. The VAS scores of low back pain and leg pain before operation and at the last follow-up were lower than those before operation, and the difference was statistically significant (P < 0.05);the ODI at the last follow-up was lower than that before operation, and the difference was statistically significant (P < 0.05). At the last follow-up, the height of intervertebral space, the height of intervertebral foramen and the sagittal diameter of dural sac were greater than those before operation, with statistically significant differences (P < 0.05);the spondylolisthesis rate at the last follow-up was lower than that before operation, with a statistically significant difference (P < 0.05). Left thigh surface numbness occurred in 2 cases (6.3%) and disappeared after 1 week;Hip flexion weakness occurred in 1 case (0.03%), which recovered after 12 days;there were no complications such as retroperitoneal hematoma, ureteral injury, retrograde ejaculation, intestinal and lumbar plexus injury. Conclusion: The early clinical effect of OLIF in the treatment of single level lumbar spondylolisthesis is significant. This surgical method is minimally invasive, safe and effective, which can significantly reduce the amount of intraoperative bleeding and reduce the risk of postoperative complications. Its main working principle is to make the annulus fibrosus, posterior longitudinal ligament and ligamentum flavum shrink and recover the height of the intervertebral space through decompression, loosening and stretching of the intervertebral space, so as to achieve the reduction of the slipped vertebral body, increase the height of the intervertebral foramen Enlarge the spinal canal volume and eliminate dynamic compression to play an indirect decompression role, improve the symptoms of low back and leg pain, and reconstruct the stability of the spine through interbody fusion. 展开更多
关键词 oblique Lateral Approach Lumbar Interbody Fusion Single Segment Lumbar Spondylolisthesis
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Greedy Randomized Gauss-Seidel Method with Oblique Direction
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作者 Weifeng Li Pingping Zhang 《Journal of Applied Mathematics and Physics》 2023年第4期1036-1048,共13页
For the linear least squares problem with coefficient matrix columns being highly correlated, we develop a greedy randomized Gauss-Seidel method with oblique direction. Then the corresponding convergence result is ded... For the linear least squares problem with coefficient matrix columns being highly correlated, we develop a greedy randomized Gauss-Seidel method with oblique direction. Then the corresponding convergence result is deduced. Numerical examples demonstrate that our proposed method is superior to the greedy randomized Gauss-Seidel method and the randomized Gauss-Seidel method with oblique direction. 展开更多
关键词 oblique Direction Linear Least Squares Problem Gauss-Seidel Method
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Control Effect of Botanical Pesticides against Ectropis oblique hmpulina and Empoasca pirisuga in Tea Plantation 被引量:6
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作者 周顺玉 尹健 马俊义 《Plant Diseases and Pests》 CAS 2011年第4期68-71,共4页
[ Objective ] The paper was to study the effects of several botanical pesticides against two pests in tea plantation. [ Method] Using randomized block de- sign, different concentrations of botanical pesticides were sp... [ Objective ] The paper was to study the effects of several botanical pesticides against two pests in tea plantation. [ Method] Using randomized block de- sign, different concentrations of botanical pesticides were sprayed during the young larvae periods of Ectropis oblique hmpulina Wehrli and peak periods of Empoasca pirisuga, the reduction rate of population and control effects were investigated after spraying for 1,3,7 and 10 d. [ Result] 5% rotenone EC 800 times had the best control effect against E. oblique hmpulina, and 0.5% veratridine soluble liquid 800 times had the best control effect against E. pirisuga. 0. 5% veratridine soluble liquid, 0.2% celangulin EC, 0.3% matrine water agent and 7.5% rotenone EC could be selected as the pesticides for the control of E. oblique hmpulina; 0. 5% veratridine soluble liquid, 0. 2% celangulin EC, 0.3% azadirachtin EC, 0.3% matrine water agent and 7.5% rotenone EC could be selected as the pesticides for the control of E. pirisuga, of which 0. 3% azadiraehtin EC 600 times showed the best durable effect against E. pirisuga with control effect of 100% after spraying for 7 d. [ Conclusion] The results provided basis for application of botanical pesticides in pests control in tea plantation. 展开更多
关键词 Botanical pesticides E. oblique hmpulina E. pirisuga CONTROL China
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Microstructural evolution of 2519-T87 aluminum alloy obliquely impacted by projectile with velocity of 816 m/s 被引量:2
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作者 梁霄鹏 李慧中 +3 位作者 黄岚 洪涛 马冰 刘咏 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第6期1270-1279,共10页
Target made of 2519-T87 aluminum alloy was obliquely impacted by a projectile. Microstructural evolution around the crater was investigated by optical microscopy (OM), transmission electron microscopy (TEM), and e... Target made of 2519-T87 aluminum alloy was obliquely impacted by a projectile. Microstructural evolution around the crater was investigated by optical microscopy (OM), transmission electron microscopy (TEM), and electron backscattered diffraction (EBSD). The micro-hardness distribution near the crater after impact was studied. The results indicate that at the entering stage, the amount of adiabatic shear band (ASB) is the most, and the precipitates are as fine as those of the target material; the micro-hardness is higher than that at the other stages. At the stable-running stage, the amount of ASB reduces as the micro-bands increase; the precipitates tend to coarsen, which leads to the decrease of the micro-hardness. At the leaving stage, there is a large amount of micro-bands; the precipitates are refined, and the micro-hardness is higher than that at the stable-running stage. The difference in the micro-hardness of the impact stages is due to work hardening and precipitate coarsening, which is caused by adiabatic temperature rise in the alloy. 展开更多
关键词 2519-T87 aluminum alloy oblique impact adiabatic shear bands micro-bands micro-hardness
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Acoustic evaluation of cementing quality using obliquely incident ultrasonic signals 被引量:2
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作者 段文星 乔文孝 +1 位作者 车小花 解辉 《Applied Geophysics》 SCIE CSCD 2014年第3期269-276,350,共9页
Ultrasonic cement bond logging is a widely used method for evaluating cementing quality. Conventional ultrasonic cement bond logging uses vertical incidence and cannot accurately evaluate lightweight cement bonding. O... Ultrasonic cement bond logging is a widely used method for evaluating cementing quality. Conventional ultrasonic cement bond logging uses vertical incidence and cannot accurately evaluate lightweight cement bonding. Oblique incidence is a new technology for evaluating cement quality with improved accuracy for lightweight cements. In this study, we simulated models of acoustic impedance of cement and cementing quality using ultrasonic oblique incidence, and we obtained the relation between cementing quality, acoustic impedance of cement, and the acoustic attenuation coeffi cient of the A0-mode and S0-mode Lamb waves. Then, we simulated models of different cement thickness and we obtained the relation between cement thickness and the time difference of the arrival between the A0 and A0′ modes. 展开更多
关键词 ULTRASONIC oblique incidence Lamb waves cementing evaluation
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The criterion of the existence or inexistence of transverse shock wave at wedge supported oblique detonation wave 被引量:7
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作者 Ai-Feng Wang Wei Zhao Zong-Lin Jiang 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2011年第5期611-619,共9页
A simplified theoretic method and numerical simulations were carried out to investigate the characterization of propagation of transverse shock wave at wedge supported oblique detonation wave.After solution validation... A simplified theoretic method and numerical simulations were carried out to investigate the characterization of propagation of transverse shock wave at wedge supported oblique detonation wave.After solution validation,a criterion which is associated with the ratio Φ (u 2 /u CJ) of existence or inexistence of the transverse shock wave at the region of the primary triple was deduced systematically by 38 cases.It is observed that for abrupt oblique shock wave (OSW)/oblique detonation wave (ODW) transition,a transverse shock wave is generated at the region of the primary triple when Φ 〈 1,however,such a transverse shock wave does not take place for the smooth OSW/ODW transition when Φ 〉 1.The parameter Φ can be expressed as the Mach number behind the ODW front for stable CJ detonation.When 0.9 〈 Φ 〈 1.0,the reflected shock wave can pass across the contact discontinuity and interact with transverse waves which are originating from the ODW front.When 0.8 〈 Φ 〈 0.9,the reflected shock wave can not pass across the contact discontinuity and only reflects at the contact discontinuity.The condition (0.8 〈 Φ 〈 0.9) agrees well with the ratio (D ave /D CJ) in the critical detonation. 展开更多
关键词 oblique detonation wave Transverse shock wave oblique shock wave Transition Numerical simulations
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Comparison of excyclotorsion following graded inferior oblique recession for primary versus secondary inferior oblique overaction 被引量:1
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作者 Donghun Lee Won Jae Kim Myung Mi Kim 《International Journal of Ophthalmology(English edition)》 SCIE CAS 2020年第8期1281-1286,共6页
AIM:To compare the changes in excyclotorsion after inferior oblique(IO)recession in patients with primary and secondary inferior oblique overaction(IOOA).METHODS:We retrospectively analyzed the data obtained from pati... AIM:To compare the changes in excyclotorsion after inferior oblique(IO)recession in patients with primary and secondary inferior oblique overaction(IOOA).METHODS:We retrospectively analyzed the data obtained from patients with IOOA who underwent graded IO recession.The patients were followed up for at least 3 mo after surgery.Fundus photographs were taken preand postoperatively,and the sum of the angles of torsion in both eyes was used to analyze changes in excyclotorsion.Patients were divided into two groups:those diagnosed with primary IOOA were enrolled in the 1’IOOA group,and those diagnosed with secondary IOOA caused by superior oblique palsy(SOP)were enrolled in the 2’IOOA group.Excyclotorsion before and after surgery were compared between the two groups.RESULTS:A total of 78 patients were enrolled in this study:34 eyes in the 1’IOOA group and 44 eyes in the 2’IOOA group.In the 78 patients,torsional angle significantly decreased from 15.31°±7.40°to 12.11°±6.53°after IO recession(P<0.001).Mean preoperative torsional angle was larger in the 2’IOOA group than in the 1’IOOA group(P=0.03).In both groups,excyclotorsion significantly decreased after IO recession(P=0.001 and P<0.001,respectively);however,there was no significant difference in the amounts of changes in excyclotorsion between the two groups.CONCLUSION:Excyclotorsion is significantly larger in secondary IOOA than in primary IOOA,and a significant decrease in the torsional angle occurs after IO recession in both types of IOOA. 展开更多
关键词 inferior oblique overaction inferior oblique recession ocular excyclotorsion STRABISMUS
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基于Oblique显示技术的钝性外伤患者肋骨隐匿性骨折的影像诊断及其分型研究 被引量:3
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作者 黄越 徐学权 +1 位作者 杜斌 胥广贺 《中国医学创新》 CAS 2019年第34期157-160,共4页
目的:应用Oblique显示技术对肋骨隐匿性骨折进行诊断及分型。方法:选取2014年3月-2018年12月就诊于本院106例明确钝性外伤史疑似肋骨隐匿性骨折患者,所有患者经常规显示技术均未发现肋骨骨折。所有患者应用Oblique显示技术检查进行肋骨... 目的:应用Oblique显示技术对肋骨隐匿性骨折进行诊断及分型。方法:选取2014年3月-2018年12月就诊于本院106例明确钝性外伤史疑似肋骨隐匿性骨折患者,所有患者经常规显示技术均未发现肋骨骨折。所有患者应用Oblique显示技术检查进行肋骨隐匿性骨折诊断,并根据骨折累及程度及表现形式进行肋骨隐匿性骨折分型。结果:106例患者共有189根肋骨存在隐匿性骨折,分为单皮质缘骨折、双皮质缘骨折及钝性骨挫伤。其中单皮质缘骨折105根,包括单纯外缘骨皮质褶皱成角64根,内缘骨皮质褶皱成角41根;内缘及外缘同时褶皱成角的双皮质缘骨折55根;骨皮质缘光滑无褶皱,仅表现为髓腔内骨髓水肿的钝性骨挫伤29根。结论:Oblique显示技术可以提高肋骨隐匿性骨折的诊断率,并能依据累及程度及表现形式进行合理分型。 展开更多
关键词 oblique显示技术 肋骨隐匿性骨折 影像诊断
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Reflection of Oblique Incident Waves by Breakwaters with Partially-Perforated Wall 被引量:19
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作者 李玉成 刘洪杰 +1 位作者 滕斌 孙大鹏 《China Ocean Engineering》 SCIE EI 2002年第3期329-342,共14页
The reflection of oblique incident waves from breakwaters with a partially-perforated front wall is investigated. The fluid domain is divided into two sub-domains and the eigenfunction expansion method is applied to e... The reflection of oblique incident waves from breakwaters with a partially-perforated front wall is investigated. The fluid domain is divided into two sub-domains and the eigenfunction expansion method is applied to expand velocity potentials in each domain. In the eigen-expansion of the velocity potential, evanescent waves are included. Numerical results of the present model are compared with experimental data. The effect of porosity, the relative chamber width, the relative water depth in the wave absorbing chamber and the water depth in front of the structure are discussed. 展开更多
关键词 wave reflection partially perforated breakwaters oblique incident waves BREAKWATER
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Oblique perforation of thick metallic plates by rigid projectiles 被引量:9
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作者 Xiaowei Chen Qingming Li Saucheong Fan 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2006年第4期367-376,共10页
Oblique perforation of thick metallic plates by rigid projectiles with various nose shapes is studied in this paper. Two perforation mechanisms, i.e., the hole enlargement for a sharp projectile nose and the plugging ... Oblique perforation of thick metallic plates by rigid projectiles with various nose shapes is studied in this paper. Two perforation mechanisms, i.e., the hole enlargement for a sharp projectile nose and the plugging formation for a blunt projectile nose, are considered in the proposed analytical model. It is shown that the perforation of a thick plate is dominated by several non-dimensional numbers, i.e., the impact function, the geometry function of projectile, the non-dimensional thickness of target and the impact obliquity. Explicit formulae are obtained to predict the ballistic limit, residual velocity and directional change for the oblique perforation of thick metallic plates. The proposed model is able to predict the critical condition for the occurrence of ricochet. The proposed model is validated by comparing the predictions with other existing models and independent experimental data. 展开更多
关键词 oblique perforation Ballistic limit Metallic plate. Rigid projectile Shear plugging
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Periodic oscillation and fine structure of wedge-induced oblique detonation waves 被引量:11
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作者 Ming-Yue Gui Bao-Chun Fan Gang Dong 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2011年第6期922-928,共7页
An oblique detonation wave for a Mach 7 inlet flow over a long enough wedge of 30 turning angle is simulated numerically using Euler equation and one-step rection model.The fifth-order WENO scheme is adopted to captur... An oblique detonation wave for a Mach 7 inlet flow over a long enough wedge of 30 turning angle is simulated numerically using Euler equation and one-step rection model.The fifth-order WENO scheme is adopted to capture the shock wave.The numerical results show that with the compression of the wedge wall the detonation wave front structure is divided into three sections:the ZND model-like strcuture,single-sided triple point structure and dual-headed triple point strucuture.The first structure is the smooth straight,and the second has the characteristic of the triple points propagating dowanstream only with the same velocity,while the dual-headed triple point structure is very complicated.The detonation waves facing upstream and downstream propagate with different velocities,in which the periodic collisions of the triple points cause the oscillation of the detonation wave front.This oscillation process has temporal and spatial periodicity.In addition,the triple point trace are recorded to obtain different cell structures in three sections. 展开更多
关键词 oblique detonation wave Wedge - Periodic oscillation Fine structure
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Characteristics and mechanism investigation on drag reduction of oblique riblets 被引量:4
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作者 GU Yun-qing FAN Tian-xing +2 位作者 MOU Jie-gang WU Deng-hao ZHENG Shui-hua 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第6期1379-1386,共8页
This work primarily focuses on the drag reduction characteristics and mechanism investigation of oblique riblets. First, a calculation model of the oblique riblets surface is established, and Reynolds stress model(RSM... This work primarily focuses on the drag reduction characteristics and mechanism investigation of oblique riblets. First, a calculation model of the oblique riblets surface is established, and Reynolds stress model(RSM) turbulence model is used for numerical simulation of the oblique riblets flow field. Subsequently, the influence of inclination angle between flow direction and arrangement direction of riblets on friction resistance and drag reduction rate is further analyzed. Through the investigation of the distribution of shear stress, pressure stress and velocity in oblique riblets boundary layer, the oblique riblets drag reduction mechanism is finally revealed. Results show that, with increase of velocity and inclination angle, the pressure resistance increases obviously, along with the decreasing of the viscous resistance distinctly. The maximum drag reduction rate of the oblique riblets is 7.33%. Moreover, when the inclination angle increases, the wall shear stress reduces on oblique riblets surface; while differential pressure increases at both sides of oblique riblets tips. In addition, when inclination angle is small, the secondary vortex at oblique riblets tips will disappear soon. New vortices will be formed inside the oblique riblets and cause the decrease of viscosity resistance. Thus, oblique riblets show a better drag reduction effect and have an effective control on boundary layer. 展开更多
关键词 oblique RIBLETS drag reduction REYNOLDS stress model (RSM) SECONDARY VORTEX numerical simulation
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