• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.7
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• pp.701-706
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• 2015

In this study, experimental and computer simulation results are compared and analyzed. Three-dimensional (3D) fabricated matrices from an MJM 3D printer were joined with poly-acetate thermoplastic polymers using a diode laser. A power range of 5-7 W was used to irradiate the boundary of two polymers. The heated polymers flowed into the matrices of the 3D fabricated structure, and reliable mechanical joining was achieved. Computer simulation showed the temperature distribution in the polymers, and flow direction was estimated based on the flux and temperature information. It was found that the more than the minimum energy threshold was required to effectively join the polymers and that two scans at low-speed were more effective than four scans at high speed.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.9
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• pp.97-106
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• 2004

A new test strategy for embedded SOC test is proposed. The SOC test is evaluated by the degree that is the amount of the total reduced test time. Since the test time for a embedded core is determined by the configuration of test wrapper, the total test time is decided by the length of the largest TAM used by the test wrapper. So the DFT(Design for Test) must be involved in the design flow. And the efficient test strategy must be settled. The all Previous test strategies are the methods that find a sub-optimal configurations of scan-chains to minimize the test time after the total TAM lines are divided into a few groups. But this is the NP-complete problem so that all attempts which examine such a TAM configuration and scan-chain division are impossible. In this thesis, a new methodology for this problem is proposed and the efficiency of the methodology is proved.

• Investigative Magnetic Resonance Imaging
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• v.15 no.2
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• pp.91-101
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• 2011

Perfusion magnetic resonance imaging (pMRI) is a special technique for evaluation of blood flow. Exogenous pMRI methods which are dynamic susceptibility contrast (DSC) and dynamic contrast-enhanced (DCE) use an intravenous bolus injection of paramagnetic contrast agent. In contrast, an endogenous pMRM method which is arterial spin labeling (ASL) use diffusible blood in body. In order to scan pMRI in human, technical optimizations are very important according to disease conditions. For examples, DSC is popularly used in patients with acute stroke due to its short scan time, while DSC or DCE provides the various perfusion indices for patients with tumor. ASL is useful for children, women who are expected to be pregnant, and in patients with kidney diseases which are problematic in nephrogenic systemic fibrosis (NSF). Perfusion MRI does not require any injection of radioisotopes. We expect that demand for perfusion MRI will be higher in evaluating drug efficacy and other treatment effects.

• CELLMED
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• v.2 no.1
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• pp.10.1-10.6
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• 2012

Acupuncture works by stimulating peripheral sensory nerves and their endings causing an increase in cutaneous blood flow and microcirculation, as well as release of neurotransmitters, neuropeptides, and hormones. SP6 Patch is a nanoscale nontransdermal device that mildly stimulates Stomach 36 (zusanli) and other acupuncture points. As stimulation of these points has been indicated to have an effect on hypothalamic function, it is of great research interest to investigate the effect of SP6 Patch on the physiology of organs that are affected by hypothalamic regulation. Bioelectrical tissue impedance data indicative of cellular physiologic organ function, using an Electro Interstitial Scan (EIS) system, were acquired from hypothalamus, pancreas, liver, intestines, kidneys, thyroid and adrenal glands in 10 (1 male, 9 females) volunteers while wearing the SP6 Patch daily for 1 week. EIS testing was performed at baseline with no patch, 30 min after wearing the patch, and after wearing the patch 12 h/day for 1 week. Subjects were instructed to keep well hydrated during the study period. All subjects served as their own control. The hypothesis was: The SP6 Patch worn 12 h/day on the Stomach 36 acupuncture point for 1 week, may significantly improve cellular physiologic functional status of different organs measured by EIS. All tested organs achieved significant improvement in their functional physiologic status after wearing the SP6 Pach 12 h/day for 1 week compared to baseline with an overall average statistical power > 89%. Based upon these results the hypothesis was accepted as true.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.22-23
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• 2005

In order to increase the critical current of coated conductor, highly Bi-axially textured substrates are required. Texture uniformity of substrate is also important to fabricate high quality superconducting coated conductor because the amount of current flow along the coated conductor is limited by the defects such as bad textured area. Therefore, we need to evaluate the distribution of texture of Ni substrate along the length before buffer layer deposition on Ni tape. R2R(reel-to-reel) XRD system was used to measure the texture of long Ni substrate continuously. $\theta-2\theta$ scan of 10 m long Ni tape was measured and indicates that some of Ni(111) planes equally remain on Ni(002) textured substrate. The results of continuous Ni(220) $\Phi$-scan indicate that average FWHM is 9$^{\circ}$ within $\pm$1.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.11 no.1
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• pp.269-283
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• 1998

Paranasal sinusitis, especially chronic is one of the most common diseases in the field of otolaryngology. It is similar to Bee Yeun(鼻淵) in oriental medicine. Most cases of sinusitis are due to anatomical abnormalities within ostiomeatal unit or disturbed mucocilliary flow. The ostiomeatal unit is the first place of contact with bacteria and allergens during aspiration, and it can be obstructed easily by minute mucosal swelling due to anatomical narrowness. Therefore the treatment of paranasal sinusitis is not easy and often leads to recurrences in spite of long term treatment or surgical therapy. We studied 83 patients who had visited our hospital with complaints of nasal symptoms; they had been diagnosed as having paranasal sinusitis through an endoscopy or CT scan in another hospital and were diagnosed as the paranasal sinusitis through a PNS series. The results were as follows: 1. Age and sex distribution: The most common occurence was found between 6-10 and 1-5 years old. The Males Were 52($62.7\%$) and Females were 31($37.3\%$). 2. By residence 58 cases lived in apts: 25 lived in houses. 3. The longest duration of disease varied from a lower of 13 to a higher of 36 months in 22 cases and from 7 to 12 months in 21 cases. 4. The most common complication & past history with otolaryngologic or allergic disease were adenoid or tonsil hypertrophy & tonsillectomy and adenoidectomy (21 cases). In decreasing order the others were atopic dematitis, otitis media with effusion and allergic rhinitis. 5. Distribution of paranasal sinus disease was most common in both maxillary sinuses in 52 cases. 12 cases showed a normal PNS X-ray series but these had been diagnosed as paranasal sinusitis with an endoscopy or CT scan in another hospital. 6. Common sinusitis - related symptoms were from highest incidence to lowest nasal obstruction, postnasal drip rhinorrhea, frontal headache, cough with sputum. 7. The most administered of prescription was Gamibangpoongtongsungsan and Sunbangpaedoksan extract. 8. In 26 cases the subjects showed significant improvement symptoms in PNS X-ray series : In 21 case showed partial improvement symptoms.

• Proceedings of the KACD Conference
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• 2008.05a
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• pp.246-257
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• 2008

The purpose of this study was to investigate the influence of various occlusal loading sites and directions on the stress distribution of the cervical composite resin restorations of maxillary second premolar, using 3 dimensional (3D) finite element (FE) analysis. Extracted maxillary second premolar was scanned serially with Micro-CT (SkyScan1072; SkyScan, Aartselaar, Belgium). The 3D images were processed by 3D-DOCTOR (Able Software Co., Lexington, MA, USA). HyperMesh (Altair Engineering. Inc., Troy, USA) and ANSYS (Swanson Analysis Systems. Inc., Houston, USA) was used to mesh and analyze 3D FE model. Notch shaped cavity was filled with hybrid (Z100, 3M Dental Products, St. Paul, MN, USA) or flowable resin (Tetric Flow, Viva dent Ets., FL-9494-Schaan, Liechtenstein) and each restoration was simulated with adhesive layer thickness ($40{\mu}m$). A static load of 200 N was applied on the three points of the buccal incline of the palatal cusp and oriented in $20^{\circ}$ increments, from vertical (long axis of the tooth) to oblique $40^{\circ}$ direction towards the buccal. The maximum principal stresses in the occlusal and cervical cavosurface margin and vertical section of buccal surfaces of notch-shaped class V cavity were analyzed using ANSYS. As the angle of loading direction increased, tensile stress increased. Loading site had little effect on it. Under same loading condition. Tetric Flow showed relatively lower stress than Z100 overall, except both point angles. Loading direction and the elastic modulus of restorative material seem to be important factor on the cervical restoration.

• Restorative Dentistry and Endodontics
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• v.33 no.3
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• pp.246-257
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• 2008

The purpose of this study was to investigate the influence of various occlusal loading sites and directions on the stress distribution of the cervical composite resin restorations of maxillary second premolar, using 3 dimensional (3D) finite element (FE) analysis. Extracted maxillary second premolar was scanned serially with Micro-CT (SkyScan1072; SkyScan, Aartselaar, Belgium). The 3D images were processed by 3D-DOCTOR (Able Software Co., Lexington, MA, USA). HyperMesh (Altair Engineering, Inc., Troy, USA) and ANSYS (Swanson Analysis Systems, Inc., Houston, USA) was used to mesh and analyze 3D FE model. Notch shaped cavity was filled with hybrid (Z100, 3M Dental Products, St. Paul, MN, USA) or flowable resin (Tetric Flow, Vivadent Ets., FL-9494-Schaan, Liechtenstein) and each restoration was simulated with adhesive layer thickness ($40{\mu}m$). A static load of 200 N was applied on the three points of the buccal incline of the palatal cusp and oriented in $20^{\circ}$ increments, from vertical (long axis of the tooth) to oblique $40^{\circ}$ direction towards the buccal. The maximum principal stresses in the occlusal and cervical cavosurface margin and vertical section of buccal surfaces of notch-shaped class V cavity were analyzed using ANSYS. As the angle of loading direction increased, tensile stress increased. Loading site had little effect on it. Under same loading condition, Tetric Flow showed relatively lower stress than Z100 overall, except both point angles. Loading direction and the elastic modulus of restorative material seem to be important factor on the cervical restoration.

• Transactions of the KSME C: Technology and Education
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• v.2 no.2
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• pp.73-80
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• 2014

Drug delivery in human upper airway was studied by the numerical simulation of oral airflow. We created an anatomically accurate upper airway model from CT scan data by using a medical image processing software (Mimics). The upper airway was composed of oral cavity, pharynx, larynx, trachea, and second generations of branches. Thin sliced CT data and meticulous refinement of model surface under the ENT doctor's advice provided more sophisticated nasal cavity models. With this 3D upper airway models, numerical simulation was conducted by ANSYS/FLUENT. The steady inspiratory airflows in that model was solved numerically for the case of flow rate of 250 mL/s with drug-laden spray(Q= 20, 40, 60 mL/s). Optimal parameters for mechanical drug aerosol targeting of predetermined areas was to be computed, for a given representative upper airways. From numerical flow visualization results, as flow-rate of drug-laden spray increases, the drag spray residue in oral cavity was increased and the distribution of drug spray in trachea and branches became more homogeneous.

• Journal of Trauma and Injury
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• v.28 no.3
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• pp.190-194
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• 2015

Blunt cerebrovascular injury is defined as a vertebral or carotid arterial structural wall injury resulting from nonpenetrating trauma. Complete traumatic internal carotid artery occlusion is very rare condition accounting for 0.08~0.4 0f all trauma patients and believed to be associated with the greatest risk of ischemic stroke reported in 50~90% in a few small series. A 55-year-male was admitted with drowsy mentality and severe headache after a fall down accident. Brain computed tomography showed a subdural hematoma at the both frontal area with a fracture of the occipital skull bone. Two days after admission, he suddenly complained with a right side hemiparesis of motor grade 2. Brain magnetic resonance diffusion demonstrated multiple high flow signal changes from the left frontal and parietal lesion. Computed tomographic angiogram (CTA) revealed absence of the left ICA flow. Trans femoral cerebral angiography (TFCA) showed complete occlusion of the left internal carotid artery (ICA) at ophthalmic segment in the left ICA angiogram and flows on the left whole hemispheric lesions through the anterior communicating artery in the right ICA angiogram. We decided to conduct close observations as a treatment for the patient because of acute subdural hematoma and sufficient contralateral cerebral flow by perfusion SPECT scan. Two weeks after the accident, he was treated with heparin anticoagulation within INR 2~4 ranges. He recovered as the motor grade 4 without another neurologic deficit after 3 months.