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Effect of duct Geometry on Shock Wave discharge

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Journal of Thermal Science 2006年第4期15卷 349-354页

作者： Y.-H.Kweon Y.Miyazato T.Aoki H.-d.kim T.Setoguchi department of Energy and Environmental Engineering Kyushu UniversityKasuga 816-8580Japan Faculty of Environmental Engineering The University of KitakyushuKitakyushu 808-0135Japan School of Mechanical Engineering Andong National UniversityAndong 760-749Korea department of Mechanical System Engineering Saga UniversitySaga 840-8502Japan

This paper describes computational work to understand the unsteady flow-field of a shock wave discharging from an exit of a duct and impinging upon a flat plate. A flat plate is located downstream, and normal to the axis of the duct. The distance between the exit of the duct and flat plate is changed. In the present study, two different duct geometries （i.e., square and cross section） are simulated to investigate the effect of duct geometry on the un-steady flows of a shock wave. In computation, the total variation diminishing （TVd） scheme is employed to solve three-dimensional, unsteady, compressible, Euler equations. Computations are performed over the range of shock Mach number from 1.05 to 1.75. Computational results can predict the three-dimensional dynamic behaviour of the shock wave impinging upon the flat plate. The results obtained show that the pressure increase generated on the plate by the shock impingement depends on the duct geometry and the distance between the duct exit and plate, as well as the shock Mach number. It is also found that for the duct with cross-section, the unsteady loads acting on the flat plate are less, compared with the square duct.

关键词： unsteady flow compressible flow shock wave shock impingement duct geometry

Modified endoscopic transnasal orbital apex decompression in dysthyroid optic neuropathy

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Eye and Vision 2021年第1期8卷 183-191页

作者： Yunhai Tu Mingna Xu Andy d.kim Michael T.M.Wang Zhaoqi Pan Wencan Wu The Eye Hospital of Wenzhou Medical University No.270 Xueyuan Xi RoadWenzhouZhejiang 325027P.R.China department of Ophthalmology New Zealand National Eye CentreThe University of AucklandAucklandNew Zealand

Background:To describe the surgical technique and assess the clinical efficacy and safety of modified endoscopic transnasal orbital apex decompression in the treatment of dysthyroid optic ***:In this retrospective research,forty-two subjects(74 orbits)who underwent modified endoscopic transnasal orbital apex decompression for the treatment of dysthyroid optic neuropathy were *** and postoperative best-corrected visual acuity(BCVA),visual field mean deviation(Md),Hertel exophthalmometry,and new onset diplopia were assessed before and after the *** Wilcoxon test was used for differential *** mixed-models’analyses were conducted to assess the potential predictors for BCVA ***:Postoperatively,the mean BCVA improved from 0.70±0.62 logMAR to 0.22±0.33 *** significantly improved in 69 eyes(93%),remained stable in 4 eyes(5%)and deteriorated in 1 eye(1%).Md of visual fields improved from−13.73±9.22 dB to−7.23±7.04 *** decreased from 19.57±3.38mm to 16.35±*** BCVA,Md of visual fields and medical rectus diameter were independent factors associated with improvements in BCVA(Pd-models’*** patients(42.9%)developed new diplopia ***:Modified endoscopic transnasal orbital apex decompression effectively restores vision in dysthyroid optic neuropathy.

关键词： Endoscopic transnasal orbital decompression dysthyroid optic neuropathy Thyroid-associated ophthalmopathy Visual acuity Visual field

The Effect of Reflector with Sound-Absorbing Material on Supersonic Jet Noise

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Journal of Thermal Science 2005年第1期14卷 22-27页

作者： Y.-H.KWEON M.TSUCHIdA Y.MIYAZATO T.AOKI H.-d.kim T.SETOGUCHI department of Energy and Environmental Engineering Kyushu University Kasuga 816-8580Japan School of Mechanical Engineering Andong National University Andong 760-749Korea department of Mechanical Engineering Saga University Saga 840-8502Japan

This paper describes an experimental work to investigate the effect of a reflector on supersonic jet noise radiated from a convergent-divergent nozzle with a design Mach number *** the present study,a metal reflector and reflectors made of three different sound-absorbing materials(grass wool and polyurethane foam)were employed,and the reflector size was *** measurement is carried out to obtain the acoustic characteristics such as frequency,amplitude of screech tone and overall sound pressure level(OASPL).A high-quality schlieren optical system is used to visualize the detailed structure of supersonic *** results obtained show that the acoustic characteristics of supersonic jet noise are strongly dependent upon the jet pressure ratio and the reflector *** is also found that the reflector with sound-absorbing material reduces the screech tone amplitude by about 5-13dB and the overall sound pressure levels by about 2-5dB,compared with those of the metal reflector.

关键词： supersonic jet supersonic jet noise screech tone OASPL reflector sound-absorbing material.

A novel technique for sacropelvic fixation using image-guided sacroiliac screws:a case series and biomechanical study

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The Journal of Biomedical Research 2019年第3期33卷 208-216页

作者： Kee d.kim Huy duong Aditya Muzumdar Mir Hussain Mark Moldavsky Bandon Bucklen department of Neurological Surgery University of California davis department of Neurosurgery Kaiser Permanente Medical Group Musculoskeletal Education and Research Center(MERC) Globus Medical Inc

In this study, we sought to assess the safety and accuracy of sacropelvic fixation performed with image-guided sacroiliac screw placement using postoperative computed tomography and X-rays. The sacroiliac screws were placed with navigation in five patients. Intact specimens were mounted onto a six-degrees-of-freedom spine motion simulator. Long lumbosacral constructs using bilateral sacroiliac screws and bilateral S1 pedicle and iliac screws were tested in seven cadaveric spines. Nine sacroiliac screws were well-placed under an image guidance system(IGS);one was placed poorly without IGS with no symptoms. Both fixation techniques significantly reduced range of motion(Pded that rigid lumbosacral fixation can be achieved with sacroiliac screws,and image guidance improves its safety and accuracy. This new technique of image-guided sacroiliac screw insertion should prove useful in many types of fusion to the sacrum, particularly for patients with poor bone quality,complicated anatomy, infection, previous failed fusion and iliac harvesting.

关键词： lumbosacral fixation sacropelvic fixation sacroiliac screw computer-assisted surgery image-guided surgery

Cervical spine fractures in osteopetrosis:a case report and review of the literature

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The Journal of Biomedical Research 2018年第1期32卷 68-76页

作者： Arjang Ahmadpour Amir Goodarzi darrin J.Lee Ripul R.Panchal Kee d.kim department of Neurological Surgery University of California-Davis Medical Center

While management of appendicular fractures has been well described in the setting of osteopetrosis, there is limited information on managing fractures of the axial spine. Here we present an osteopetrotic patient with multiple traumatic multiple, comminuted, unstable cervical spinal fractures managed with non-operative stabilization, and provide a review of the pathophysiology, genetic characteristics, and special considerations that must be explored when determining operative versus non-operative management of spinal injury in osteopetrosis. A PubMed query was performed for English articles in the literature published up to June 2016, and used the following search terms alone and in combination：＂osteopetrosis＂, ＂spine＂, ＂fractures＂, ＂osteoclasts＂, and ＂operative management＂. Within four months after initial injury, treatment with halo vest allowed for adequate healing. The patient was asymptomatic with cervical spine dynamic radiographs confirming stability at four months. On four-year follow up examination, the patient remained without neck pain, and CT scan demonstrated partially sclerotic fracture lines with appropriate anatomical alignment. In conclusion, external halo stabilization may be an effective option for treatment of multiple unstable acute traumatic cervical spine fractures in patients with osteopetrosis. Given the challenge of surgical stabilization in osteopetrosis, further research is necessary to elucidate the optimal form of treatment in this select patient population.

关键词： osteopetrosis spine fractures osteoclasts operative management

Magnetic Properties and Coercivity of MnGa Films deposited on different Substrates

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Journal of Materials Science & Technology 2017年第3期33卷 291-294页

作者： J.N.Feng W.Liu W.J.Gong X.G.Zhao d.kim C.J.Choi Z.d.Zhang Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Powder and Ceramics division Korea Institute of Materials Science

MnGa films were grown by magnetron sputtering on thermally oxidized Si（Si/SiO2） and glass substrates. Films grown on single-crystal Si（100） substrate with different underlayers were prepared for comparison. It is found that the Si/SiO2 substrate is more suitable for growing high-coercivity MnGa films than the glass substrate, which is the result of the isolated-island-like growth. A coercivity of 9.7 kOe can be achieved for the 10 nm MnGa films grown on Si/SiO2 substrate at substrate temperature TS of 450 °*** experimental conditions are specified by changing the thickness of the MnGa films and the temperature of the substrates.

关键词： Atomic force microscopy Coercivity Magnetic properties Magnetron sputtering Thin film

Stereotactic guidance for navigated percutaneous sacroiliac joint fusion

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The Journal of Biomedical Research 2016年第2期30卷 162-167页

作者： darrin J.Lee Sung-Bum kim Philip Rosenthal Ripul R.Panchal Kee d.kim department of Neurological Surgery University of California-Davis Medical Center department of Neurological Surgery Kyung-Hee Medical Center

Arthrodesis of the sacroiliac joint（SIJ） for surgical treatment of SIJ dysfunction has regained interest among spine *** techniques described in the literature most often utilize intraoperative fluoroscopy to aid in implant placement;however,image guidance for SIJ fusion may allow for minimally invasive percutaneous instrumentation with more precise implant *** the following cases,we performed percutaneous stereotactic navigated sacroiliac instrumentation using O-arm^（？）multidimensional surgical imaging with StealthStation^（？）navigation（Medtronic,***,MN）.Patients were positioned prone and an image-guidance reference frame was placed contralateral to the surgical site.O-arm^（？） integrated with StealthStation^（？） allowed immediate *** skin incision was planned with an image-guidance *** image-guided awl,drill and tap were utilized to choose a starting point and *** titanium cage（s） packed with autograft and/or allograft were then placed.O-arm^（？） image-guidance allowed for implant placement in the SIJ with a small skin ***,we could not track the cage depth position with our current system,and in one patient,the SIJ cage had to be revised secondary to the anterior breach of sacrum.

关键词： sacroiliac joint arthrodesis technique image guidance

Atomistic Simulation of Phase Transformation and Fracture in Ordered Intermetallics

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Journal of Materials Science & Technology 1993年第5期9卷 355-359页

作者： P.C.Clapp C.S.Becquart d.kim Y.Shao J.A.Rifkin Center for Materials Simulation,Institute of Materials Science,University of Connecticut,Storrs,CT 06269-3136,USA

A review of computer simulations carried out at our Center for Materials Simulation applied to stud- ying the different atomistic processes of fracture and displacive (martensitic) transformations is pres- *** these processes can happen extremely rapidly and involve only a small number of atoms initially,they are ideally suited for molecular dynamics type simulations which can currently only span times of the order of one nanosecond and involve at most a million atoms.A method is also presented for simulating much larger samples for much longer times through the use of the Monte-Carlo technique combined with a Ginzburg-Landau free energy functional,where the rele- vant material parameters are determined from molecular dynamics runs on the same alloy system.A summary of studies on fracture simulations in the ordered intermetallics NiAI and RuAl is given,as well as a discussion of the observation and analysis of the heterogeneous nucleation of the martensitic transformation in NiAI which shows localized soft mode *** is concluded that computer simulations,whether of the atomistic molecular dynamics type or of the larger scale Monte-Carlo variety,are rapidly becoming of greater and greater use in understanding the properties of solids under a wide rancle of temperature and stress conditions.

关键词： computer simulation phase transformation fracture ordered intermetallics

全自动多参数影像组学模型用于鉴别成人毛细胞星形细胞瘤与高级别胶质瘤

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国际医学放射学杂志 2022年第5期45卷 611-612页

作者： Y.W.Park J.Eom d.kim S.S.Ahn E.H.kim S.G.Kang 何品

摘要目的建立一种全自动影像组学模型来鉴别成人毛细胞星形细胞瘤（PA）和高级别胶质瘤（HGG）。方法该回顾性研究纳入302例成年病人，包括PA(62例)和HGG(240

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