• The Journal of the Korean bone and joint tumor society
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• v.6 no.1
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• pp.30-34
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• 2000

Giant cell tumor of the small bones of the hands and feet is rare. Giant cell tumors in these locations develop at young age, are more commonly multifocal, and show the higher risk of recurrence than those at the end of the long bone. It should be differentiated from the other lesions of the hands, such as giant cell reparative granuloma, aneurysmal bone cyst and enchondroma. We experienced a case of giant cell tumor in the proximal phalanx of the left hand with swelling and pain. Curettage and bone graft were performed. Histologically large number of giant cells were distributed diffusely in the highly cellular stroma containing sheets of mononuclear cells. Secondary aneurysmal bone cyst and hemorrhage were associated.

• Transactions of the Korean hydrogen and new energy society
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• v.13 no.4
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• pp.270-278
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• 2002

Mg and Mg alloys are attractive hydrogen storage materials because of their lightweight and high absorption capacity. Their range of applications could be further extended if their hydrogenation properties and degradation behavior could be improved, The main emphasis of this study was to find an economic manufacturing method for Mg-Ti-Ni-H systems, and to investigate their hydrogenation properties, In order to examine hydrogenation behavior, a Sieverts type automatic pressure-composition-isotherm(PCI) apparatus was used and the experiments were performed at 423, 473, 523, 573, 623 and 673K. The results of thermogravimetric analysis(TGA) reveal that the absorbed hydrogen contents are around 2.5 wt% for ($Mg_9Ti_1$)-10 wt% Ni. With increased Ni content, the absorbed hydrogen content decreases to 1.7 wt%, whereas the dehydriding starting temperatures are lowered by some 70-100K. The results of PCI on ($Mg_9Ti_1$)-20 wt% Ni show that its hydrogen capacity is around 5.3 wt% and its reversible capacity and plateau pressure are also excellent at 523K and 573K. In addition, the reaction enthalpy, $\Delta$HD.plateau, is $30.6{\pm}5.7kJ/molH_2$.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.1
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• pp.43-48
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• 2010

The heat sink system for a main board in a network server computer is built on printed circuit board by an anchor structure, mounted by eutectic SnPb solder. The solder creeping is caused by a constant high temperature condition in the computer and it eventually makes fatal failures. The FE model is used to calculate the stress and predict the life of soldered anchor in the computer. In the model, Anand constitutive equation is employed to simulate creep characteristics of solder. The creep test is conducted to verify and calibrate the solder model. A special jig is designed to mitigate the flexure of printed circuit board and to get the creep deformation of solder only in the test. Test results are compared with analysis and calibration is conducted on Anand model's constants. Precise life prediction of soldered anchor in creep condition can be performed by this model.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.1
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• pp.127-130
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• 2010

This paper deals with the formability of DP590 steel considering the strain rate. The strain hardening coefficient, elongation and r-value were obtained from the static and dynamic tensile test. As strain rate increases from static to 100/s, the strain hardening coefficient and the uniform elongation decrease and the elongation at fracture and r-value decrease to 0.1/s and increase again to 100/s. The high speed forming limit tests with hemi-spherical punch were carried out using the high speed crash testing machine and high speed forming jig. The high speed forming limit of DP590(order of $10^2$/s) decreases compared to the static forming limit(order of $10^{-3}$/s) and the forming limit band in high speed forming test is narrower than that in the static forming test. This tendency may be due to the development of brittleness with increase of stain rate.

• Mass Spectrometry Letters
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• v.8 no.4
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• pp.109-113
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• 2017

Single analytical procedure including extraction, liquid chromatography, and mass spectrometric analysis was evaluated for the simultaneous measurement of lysophospholipids (LPLs). LPLs, particularly, lysophosphatidic acids (LPA) and sphingosine 1-phosphate (S1P) are lipid messengers ubiquitously found in various biological matrix. The molecular species mediate important physiological roles in association with many diseases (e.g. cancer, inflammation, and neurodegenerative disease), which emphasize the significance of the simple and reliable analytical method for biomarker discovery and molecular mechanistic understanding. Thus, we developed analytical method mainly focusing on, but not limited by those lipid species S1P and LPA using reverse phase liquid chromatography-tandem mass spectrometry (RPLC-ESI-MS-MS). Extraction method was modified based on Folch method with optimally minimal level of ionization additive (ammonium formate 10 mM and formic acid). Reverse-phase liquid-chromatography was applied for chromatographical separation in combination with negative ionization mode electrospray-coupled Orbitrap mass spectrometry. The method validation was performed on human blood plasma in a non-targeted lipid profiling manner with full-scan MS mode and data-dependent MS/MS. The proposed method presented good inter-assay precision for primary targets, S1P and LPA. Subsequent analysis of other types of LPLs identified a broad range of lysophosphatidylcholines (LPCs) and lysophosphatidyl-ethanolamines (LPEs).

• Archives of Plastic Surgery
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• v.37 no.3
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• pp.313-316
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• 2010

Purpose: Tie-over dressing is widely used to secure skin grafting on face, body, or extremities. It can be a rather complicated task and is not easy to make compressive dressing again if performed in a conventional method. So, we hereby introduce an easy reproducible tie over dressing method. Methods: After completing the skin graft, Cut the silastic drainage longitudinally in half and spread to the grafted skin margin. Drainage is fixed by using the stapes or sutures. A fluffy gauze bolus dressing is placed over a furacin impregnated gauze and wrapped around. After suturing the distal margin of silastics with opposite side using the silk thread either 5 - 0 or 3 - 0, knot of suturing, which is pressed down against the dressing while the threads are tightened, is made into center of each sides. Results: It can make dressing again after observing the grafted skin, and it can also make pressure on the grafted area evenly until the grafted skin is taken. Conclusion: This dressing method makes the surgeons and patients comfortable. To surgeons, it provides more rapid and easier way to do dressing, and to patients, it eliminates pain caused by redressing.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.620-624
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• 2009

한국농어촌공사에서 2008년도 환경부 하수처리장 재이용사업으로 선정된 제주특별자치도 서부(판포)하수처리장 농업용수재이용 사업을 위탁받아 사업을 진행하고 있다. 하수처리수를 농업용목적으로 재이용하기 위해서는 농업용수 재이용수질기준에 우선 적합해야하고 작물재배실험 및 수질, 토양, 생태환경 영향 뿐만아니라 공중보건위생 위험도 등 종합적이고 체계적인 연구결과를 바탕으로 적용해야한다. 이를 위해 수자원 프런티어사업단의 "농업용수재이용시스템적용 연구"에서는 하수처리수의 농업용수 재이용과 관련한 종합적인 연구를 통해 농업환경피해를 최소화하고 안전성 확보를 위한 방안을 수립하고 있다. 서부하수처리장은 제주도 한경면 판포리에 위치하여 2007년도에 준공하였고 2008년도부터 본격적으로 가동중이다. 재이용 공급대상 농경지는 처리장의 주변 농경지로 249ha를 대상으로 하고 있으며 사업시행을 위해 타당성 분석, 기본계획 및 실시설계를 시행하였고 2009년 12월까지 시설의 설치 및 시험가동 완료를 목표로 하고 있다. 본 연구에서는 농업용수 재이용사업의 계획 수립을 위해 필요한 분석활동 내용과 안전하게 제주도 하수처리수를 재이용할 수 있는 농업용수 재이용시스템 설계내용을 중심으로 기술하였다. 현재 농촌은 도시화가 전국으로 확산되면서 농촌의 쾌적성은 점차 훼손되었고 하천 호소의 수질이 더욱 악화되고 있다. 또한 농촌지역의 도시화에 따라 하수처리장의 농촌지역에도 늘어가고 있으며 이제는 농촌지역과 도시지역이 구분되지 않고 혼합되어 있는 형태로 발전하고 있기 때문에 과거의 농업활동도 변화되고 있으며, 하천에서 취수하는 용수중에서 농업용수로의 사용이 부적합한 용수가 취수되고 있다. 따라서 하수처리수의 농업용수 재이용시스템과 같이 수처리를 이용한 농업용수의 공급방안이 확대될 것으로 판단된다.

• The Journal of Korean Academy of Prosthodontics
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• v.35 no.1
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• pp.130-143
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• 1997

A heat-pressed technique(IPS-Empress, Ivoclar) has been described to construct single unit crown, inlay/onlay and veneers using a partially pre-cerammed and pre-colored glass-leucite ingot that has the greateast strength by the combination of heat-pressed procedure through the smalldiameter sprue and heat treatment procedure. The purpose of this study was to evaluate the flexure strength of a heat-pressed ceramic material(IPS-Empress) without simulated firing treatments according to pontic designs. Two groups of 9 disks(1.4mm thick, 14mm in diameter) each using two types of sprues with different diameters($({\Phi}2.8\;,{\Phi}1.8)$) and numbers were prepared. The specimens were mounted in the testing jig. The flexural strengths were determined, by means of the bi-axial bending test, by loading the center of disk to failure using a universal testing machine(Zwick 145141, Zwick, Germany) at a cross-head speed of 1.0 mm/min. The means flexural strength value of one group using a sprue with ${\Phi}2.8$ was $140.4{\pm}8.0Mpa$. That of the other group using two sprues with ${\Phi}1.8$ was $151.8{\pm}10.3Mpa$. After analysis, results showed that there was a statistical difference between groups(t=2.33m p<0.05). No clnical implications were drawn from these data because of absence of simulated firing treatment.

• Journal of the Korean Institute of Gas
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• v.21 no.5
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• pp.77-82
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• 2017

Thus, chemicals are managed under 9 related central government department and 16 relevant laws with program such as Process Safety Management and Offsite Consequence Analysis in korea. Guidelines for set the endpoint concentration for chemcals based on the ERPG-2 (Emergency Response Planning Guidelines-2) and AEGL-2 (Acute Exposure Guidelines Level-2). but ERPG and AEGL do not describe exposure for less than 10 minutes. because of this, each guidelines define criteria differently for short time less than 10 minutes exposure. This indefinite exposure criteria would give rise to a confusion in the chemical plants, and potentially lead to a critical decision making error when accidents happen. In an effort to apply guidelines with evenly-distributed initial time frame, AEGL concentrations within 10 minute exposure time were evaluated by examining statistical regression curves. The results were in good agreement with those from the Probit Function based on each AEGL grade to explain 3 different threshold levels of exposure effects. Resultant re-enforced guidelines for endpoint chemical concentrations are, therefore, to provide powerful tool to assess and manage the risk associated with any potential chemical accidents at an early stage.

• Journal of Biomedical Engineering Research
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• v.29 no.2
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• pp.132-138
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• 2008

We investigated the biomechanical properties of a newly designed self-expansion type anterior cruciate ligament (ACL) anchor. The ACL anchor consists of the ring section giving the elastic force, the wedge for maintaining in contact with the femur tunnel wall and the link suspending hamstring graft or artificial ligament. The main design parameters that determine the performance of this device were the expansion angle (${\theta}$) and the thickness ($t_R$). The Ti6Al4V anchors were heated after inserting in a jig for 1 hour at $800^{\circ}C$ in a protective argon gas atmosphere and allowed to cool to room temperature in the furnace. In order to investigate the influence of the expansion angle and the thickness of the ring on the biomechanical properties of the anchor, the maximum pull-out load, stiffness and slippage of the ACL anchor were measured using the pull-out tester, and statistical analyses were also executed. The present results showed that the design parameters gave a significant effect on the performance of the self- expansion type of anchor. The pull-out load of the ACL anchors significantly increased as the thickness of the ring section was increased, having a similar trend for both expansion angles. The ACL anchor showed about 2.5 times higher values of the pull-out load than that of the minimum load (500N)required for the "accelerated rehabilitation". The optimum ${\theta}$ and $t_R$ values of this ACL anchor were suggested to have sufficient resistance against the pull-out force, high stiffness and relatively low slippage after ACL reconstruction.