• Journal of architectural history
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• v.25 no.5
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• pp.41-50
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• 2016

This thesis mainly deals with how 'count of Ryang' was used in the Daehan Empire. Count of Ryang means how many purlins were used in the building with longitudinal section. As a result, the notion of Ryang in the Daehan Empire does not differ from now one. But the usages of that are different from the Joseon Dynasty, and from the present. In the Daehan Empire, count of Ryang mainly was appeared with another word, count of Kan. In the Joseon Dynasty, they used the count of Ryang combined with Kan. Count of Kan had the meaning of purlin-directional length. By doing that, count of Ryang indicates the size of flank, count of Kan indicates the length of front. But in the Daehan Empire, count of Kan, especially the beam-directional length was considered at first, and then count of Ryang. Separately they used another count of Kan meaning the area of building. By using the combined words, count of Kan and Ryang in the beam direction, they got focused on the frame of wooden structure than before.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.2
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• pp.191-195
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• 2012

Heavy flint optical glass(SF57HHT) is new material that has extremely high transmittance. Due to brittleness and high hardness, optical glass is one of the most difficult to materials for ultra-precision turning. According to the hypothesis of ductile machining, all materials, regardless of their hardness and brittleness, will undergo transition from brittle to ductile machining region below critical undefromed chip thickness. In this study, cutting test was carried out to evaluate cutting performance of heavy flint glass using ultra-precision machine with single crystal diamond bite. The machined workpiece surface topography, tool wear and surface roughness were examined using AFM and SEM. The experimental results indicate that the machining mode become the brittle mode to ductile mode, when the maximum undeformed chip thinkness is large than critical value. Tool wear mainly occurs on the flank face and its wear mechanism is dominated by abrasion. This study demonstrates the feasibility of SF57HHT by diamond turning.

• Childhood Kidney Diseases
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• v.5 no.1
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• pp.64-68
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• 2001

The nutcracker syndrome is the congestion of left renal vein due to the compression of left renal vein by the aorta and the superior mesenteric artery and has been known as tile cause of hematuria with or without left renal flank pain, mild to moderate proteinuria and orthostatic proteinuria. We present here one case of 13.5 year of girl has severe typical nutcracker syndrome with orthostatic protinuria and idiopathic chronic fatigue. (J. Korean Soc Pediatr Nephrol 5 . 64- 8, 2001)

• Journal of the Korean Society for Precision Engineering
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• v.26 no.5
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• pp.48-56
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• 2009

In this paper, laser-assisted machining(LAM) has been employed to machine hot isostatically pressed (HIPed) Si3N4 work pieces. Due to little residual flaws and porosity, HIPed $Si_3N_4$ work pieces are more difficult to machine compared to normally sintered $Si_3N_4$ workpieces. In LAM, the intense energy of laser was used to enhance machinability by locally heating the workpiece and thus reducing yield strength. In experiments, the laser power ranges from 200W to 800W and the diameter of work pieces is 16mm. While machining, the surface temperature was kept nearly constant by laser heating except for a short period of rise time of max. 58 seconds. Results showed as feed rate increases the surface temperature of $Si_3N_4$ workpieces decreases slightly, whereas the effect of depth of cut is disregardable. With a laser power of 800W, achievable maximal depth of cut as 0.7mm and feed rate was 0.03mm/rev.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.1038-1042
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• 2002

Monitoring of the drill wear and hole quality change is conducted during the drilling process. Cutting force measured by tool dynamometer is a evident feature estimating abnormal state of drilling. One major difficulty in using tool dynamometer is that the work piece must be mounted on the dynamometer, and thus the machining process is disturbed and discontinuous. Acoustic transducer do not disturb the normal machining process, and provide a relatively easy way to monitor a machining process for industrial application. For this advantage, AE signal is used to estimate the abnormal state. In this study vision system is used to detect flank wear tendency and hole quality, there are many formal factors in hole quality decision circularity, cylindricity, straightness, and so on, but these are difficult to measure in on-line monitoring. The movement of hole center and increasement of hole diameter is presented to determine hole quality As the results of this experiment, AE RMS signal and measurements by vision system are shown the similar tendency as abnormal state of drilling. And detection of the abnormal states using BPNs was achieved 96.4% reliability.

• Korean Journal of Materials Research
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• v.14 no.9
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• pp.649-654
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• 2004

In this paper, the fracture toughness and mechanisms of failure in a random SiC-whisker/$Al_{2}O_3$ ceramic composite were investigated using in situ observations during mode I(opening) loading. $SiC_{w}/Al_{2}O_3$ composite was obtained by hot press sintering of $Al_{2}O_3$ powder and SiC whisker as the matrix and reinforcement, respectively. The whisker and powder were mixed using a turbo mill. The composite was produced at SiC whisker volume fraction of $0.3\%$. Compared with monolithic $Al_{2}O_3$, fracture toughness enhancement was observed in $SiC_{w}/Al_{2}O_3$ composite. This improved fracture toughness was attributed to SiC whisker bridging and crack deflection. $SiC_{w}/Al_{2}O_3$ composite exhibited typically brittle fracture behavior, but a fracture process zone was observed in this composite. This means that the load versus load-line displacement curve of $SiC_{w}/Al_{2}O_3$ composite from a fracture test may involve a small non-linear region near the peak load.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.11 no.2
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• pp.17-23
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• 2002

A cylindrical capacitance-type spindle displacement sensor was developed and its effectiveness as a system to monitor cutting forces during hard turning was tested in this research. The sensor was installed between the face of spindle cover and the chucking element and measured pure radial motion of the spindle under the condition with presence of roundness error at measured surface. To prove the effectiveness of the developed system hard aiming tests using ceramic inserts and tool steel as workpiece were conducted. The workpiece was hardened up to 65 Rc. The variations of pure radial motion of the spindle ware measured during the cutting tests. The signals from the sensor showed the same pattern of cutting force variations from the tool dynamometer due to the progress of tool wear. As the flank wear of the ceramic tool increased both static component of cutting forces and the amount of center shift of spindle orbit increased, Results from the research showed that the developed sensor could be utilized as an effective and cheap on-line sensing device to monitor cutting conditions and tool performance in the un-manned machining center.

• Transactions of Materials Processing
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• v.19 no.3
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• pp.160-166
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• 2010

In this paper, the process parameters of thread rolling were designed based on the numerical analysis results. Firstly, the effective analysis conditions that guarantee the reliability of the analysis results were found. To find the effective analysis conditions, the analyses were carried out for various numbers of teeth. And then, the effects of the process parameters such as tool shape and temperature on the thread rolling performance were investigated. The formability in thread rolling process was evaluated in terms of Cockcroft-Latham damage value. In order to evaluate formability, Cockcroft-Latham damage value was normalized by the critical damage value which was obtained from the analysis of uniaxial tensile test. The analyses were carried out using DEFORM-3D. The results showed that the flank angle and crest round had an effect on the thread rolling load. It was also shown that temperature had significant effects on the effective strain distribution, rolling load, and damage. With the reduced formability of stainless steel at higher temperature, it was shown that the normalized damage values increased as the process temperature.

• The Korean Journal of Pain
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• v.12 no.2
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• pp.263-267
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• 1999

We have observed retroperitoneal hematoma after trigger point injections of quadratus lumborum in a patient with chronic low back pain. Severe flank pain and dyspnea was observed three hours after injection of local anesthetic and steroid to the trigger point of quadratus lumborum muscle. There was fuge hematoma in abdominal CT image around the right kidney, which displaced and compressed the kidney anteriorly. Following infusion of contrast media, extravasation through renal vein and IVC was notified. Patient had a past history of having been treated with platelet aggregation inhibitor and lower dose aspirin treatment after cerebral ischemia for a year, but coagulative function was within normal range. Patient was admitted 12 days for bed rest, pain control and transfusion. We need to take greater care with a frequent aspiration and exact direction of needle, during trigger point injection of quadratus lumborum, particu right side, to avoid vascular injury.

• Journal of Korean Neurosurgical Society
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• v.29 no.8
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• pp.1074-1079
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• 2000

We report a case of pyogenic spondylitis on L2 and L3 with diffuse epidural abscess up to T4 to L3 and large psoas abscess. A forty-nine-year old male was presented with progressive back pain, left flank pain and ab-dominal distention, weakness of the both legs and voiding and defecation difficulty during last 2 months. Initially multiple coronal hemilaminectomies from T4 to T12 were done for the treatment of diffuse thoracic epidural ab-scess. Then second operation via left retroperitoneal approach was performed for lumbar spondylitis and psoas abscess on third day after initial operation. After removal and curettage of pyogenic psoas and epidural abscess and spondylitis (L2-L3), iliac bone grafting with Keneda instrumentation from L1 to L4 was done simultaneously. Postoperative course has been unevenful without recurrent infection. The literature on diffuse epidural and large psoas abscess with pyogenic spondylitis are reviewed and instrumentation for stabilization of pyogenic spondylitis is also discussed.