• Ocean and Polar Research
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• v.43 no.4
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• pp.295-306
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• 2021

A field scale productivity analysis is required for the development of gas hydrate in marine sedimentary layers to verify the field applicability of production techniques and to improve productivity. In this study, the productivity resulting from the application of depressurization using multi-wells for the development of gas hydrate in the Ulleung Basin, East Sea of Korea, was determined. A numerical analysis model reflecting the conditions of candidate sites for the Ulleung Basin was constructed, and the productivity and dissociation behavior were comparatively analyzed. The pressure propagation and gas hydrate dissociation region by the multi-wells were wider and the productivity was higher than that of a single well. Different depressurization effects according to the spacing of multi-wells affected productivity. The results provide basic data for productivity analysis when establishing a field test production plan for the Ulleung Basin.

• Journal of the Korean Orthopaedic Association
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• v.56 no.6
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• pp.519-524
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• 2021

Meningitis after spinal surgery occurs rarely but can be fatal. A 49-year-old male was diagnosed with compressive myelopathy due to cervical disc herniation at the C 5, 6 level and underwent anterior cervical discectomy and fusion (ACDF). He complained of severe neck pain and stiffness with fever postoperatively and one week after surgery, the patient presented with abrupt tetraplegia. The follow-up magnetic resonance imaging and cerebrospinal fluid analysis revealed bacterial meningitis complicated by myelitis. The patient was treated with antibiotics and steroid, but the outcome was poor. The authors report a case of meningitis combined with myelitis following anterior cervical spinal surgery.

• Applied Biological Chemistry
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• v.37 no.1
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• pp.9-13
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• 1994

Baikhaju, the traditional Korean rice wine was brewed and distilled at various conditions-at different pressure (760, 460, 260 mmHg), different reflux ratio (3.1 : 1, 1 : 1) and different column conditions (packed and unpacked), and distillation operation was investigated. The sample wine, Baikhaju showed alcohol content of 14.2%, acidity 8.3 (g/100 ml), ethyl acetate 49 ppm, fusel oil 657 ppm. As the distillation was proceeded, alcohol concentration of distillate was decreased and that was higher in atmospheric pressure rather than reduced pressure. When the pressure was increased, the slope showed the relation of alcohol concentration between still liquid and vapour was increased, and also as the reflux ratio was increased, alcohol concentration of distillate was increased, and that was 0.56 mole at the reflux ratio 3.1 : 1 at atmospheric pressure, where 0.54 mole at 1 : 1 reflux ratio. As the distillation was proceeded, the rate of distillation was decreased, and that was higher values in the reduced pressure than atmospheric pressure. The maximum value (0.14 ml/s) of rate of distillation was observed in the packed column at 260 mmHg. As the reflux ratio was increased, the rate of distillation was decreased, and that was 0.05 ml/sec at reflux ratio 3.1 : 1 at atmospheric pressure, where 0.06 ml/sec at 1 : 1 reflux ratio.

• Journal of Korean Neurosurgical Society
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• v.29 no.10
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• pp.1365-1371
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• 2000

Objectives : Spinal cord compression is a rare presentation of non-Hodgkin's lymphoma(NHL), occurring in 0.1% to 10.2% of patients. Primary spinal extradural NHL, i.e. occurring in the absence of any detectable extraspinal lymphoproliferative disorder, has a potentially favourable outcome if diagnosed and treated early. The authors describe two patients with a clinical picture of acute spinal cord compression as the first presentation of NHL. Methods : The patients were 48-year-old female and 27-year-old female. Both presented with back pain followed by acute paraparesis and voiding difficulty. One patient was diabetic. Plain radiographs of the spine were not specific. Thoracic spine magnetic resonance imaging(MRI) revealed evidence of extradural soft tissue mass extending multiple vertebral segments. Results : The patients underwent emergency laminectomy for decompression and tissue diagnosis. Histological and immunohistochemical study revealed B-cell lymphoma, intermediate grade in both patients. Postoperative staging did not reveal any additional lesions other than extradural manifestation of the malignant lymphoma. Surgery with additional chemotherapy and radiotherapy allowed the clinical improvement of both patients. Conclusion : The authors report two patients with a clinical picture of acute spinal cord compression as the first presentation of NHL, and stress that primary spinal epidural NHL should be a diagnostic consideration in the patient without prior history of malignancy who presents with a prodrome of back pain followed by a rapid neurological deterioration.

• Nuclear Engineering and Technology
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• v.28 no.2
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• pp.129-136
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• 1996

Influence diagram method is applied to containment performance analysis of Young-Gwang 3&4 in an effort to overcome some drawbacks of current containment performance analysis method. Event tee methodology has been adopted as a containment performance analysis method. There are, however, some drawbacks on event tree methodology. This study is to overcome three major drawbacks of the current containment performance analysis method : 1) Event tree cannot express dependency between events explicitly. 2) Accident Progression Event Tree (APET) cannot represent entire containment system. 3) It is difficult to consider decision making problem. To resolve these problems, influence diagrams, is proposed. In the present ok, the applicability of the influence diagrams has been demonstrated for YGN 3&4 containment performance analysis and accident management strategy assessments of this study are in good agreement with those of YGN 3&4 IPE. Sensitivity analysis has been peformed to identify relative important variables for each early containment failure, late containment and basemat melt-though. In addition, influence diagrams are used to assess two accident management strategies : 1) RCS depressurization, 2) cavity flooding. It is shown that influence diagrams can be applied to the containment performance analysis.

• Journal of the Korean Wood Science and Technology
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• v.19 no.1
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• pp.31-63
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• 1991

It was proved that in conventional kiln drying of disks piling position in the kiln exerted a great influence on drying rates, and the larger the variation of disk diameter, the more undulating drying rates of disks. While in vacuum drying disks there was no influence on drying rates. By the end-wrapping treatments and the radial direction of disks tangential surface stresses in the core of disks were slightly compressive in three species. In control disks the drying stresses distributed into one step-style that compressive stresses in the pith side of 6cm from pith were larger than those in the bark side, while in the disks end-wrapped with Korean paper the drying stresses distributed uniformly, because flow rates of free water in disks had no difference between heart-and sap-wood by obstruction of evaporating water from surface of disks by end-wrapping with Korean paper. And end-wrapping with Korean paper considerably restrained those. Tangential differential shrinkage stresses developed the maximum tensile stress near the bark and with approaching the pith the stresses gradually reduced and changed into compressive stresses in near the pith. At the end of vacuum drying the maximum tangential tensile stresses of disks end-wrapped with Korean paper were smaller than those of control disks, and critical moisture contents causing the V-shaped crack of disks end-wrapped with Korean paper were lower than those of control disks because of the set by obstruction of evaporating water of end-wrapping with Korean paper. In the experiment of vacuum drying stress distribution the disks end-wrapped with Korean paper or aluminum foil in three species were free from V-shaped cracks and control disks were defected very slightly by V-shaped cracks. And also disks end-wrapped with Korean paper were free from heart checks in Alnus japonica and Juglans sinensis, and heart checks were occurred very slightly in others. Especially, not to speak of disks end-wrapped with Korean paper, vacuum drying of disks end-wrapped with aluminum foil prevented effectively drying defects, moreover drying times could be shortened, that is. Ginkgo biloba, Alnus japonica, and Juglans sinensis disks could be dried from green to in-use moisture content in 110 hours, 272 hours, and 407 hours, respectively.

• Korean Journal of Food Science and Technology
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• v.20 no.1
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• pp.63-71
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• 1988

Total lipid contents of tomato fruits were 97.6mg% and composed of neutral lipid(45.1mg%), phospholipid(31.2mg%) and glycolipid(12.4mg%). The contents of neutral lipid were slowly increased from the period of climacteric rise, but those of glycolipid and phospholipid were slowly decreased at the end of storage period. Major fatty acids in all lipids were identified to be palmitic, stearic, linoleic and oleic acids. The contents of linoleic acid in all lipids at $25^{\circ}C$ and those in neutrallipid at $15^{\circ}C$ were decreased, while those in phospholipid were slightly increased during storage. The contents of palmitic acid in neutral lipid were decreased, whereas those in glycolipid and phospholipid have a tendency to increase during storage. As for normal atmospheric pressure-normal temperature(NAP-N) condition, volatiles from homogenated tomato fruits were positively correlated with palmitic acid of neutral lipid, whereas negatively correlated with linoleic acid. As for subatmospheric pressure-low temperature(SAP-L) condition, the relationship between volatiles and fatty acids of neutral lipid was similar to NAP-N condition. Volatiles were positively correlated with linoleic acid of glycolipid and stearic acid of phosholipid, whereas negatively correlated with oleic acid of glycolipid and palmitic acid of phospholipid, respectively.

• Tunnel and Underground Space
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• v.26 no.2
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• pp.59-67
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• 2016

In this paper, we perform a numerical analysis to evaluate the potential of fault reactivation during gas production from hydrate bearing sediments and the moment magnitude of induced seismicity. For the numerical analysis, sequential coupling of TOUGH+Hydrate and FLAC3D was used and the change in effective stress and consequent geomechanical deformation including fault reactivation was simulated by assuming that Mohr-Coulomb shear resistance criterion is valid. From the test production simulation of 30 days, we showed that pore pressure reduction as well as effective stress change hardly induces the fault reactivation in the vicinity of a production well. We also investigated the influence of stress state conditions to a fault reactivation, and showed that normal fault stress regime, where vertical stress is relatively greater than horizontal, may have the largest potential for the reactivation. We tested one simulation that earthquake can be induced during gas production and calculated the moment magnitude of the seismicity. Our calculation presented that all the magnitudes from the calculation were negative values, which indicates that induced earthquakes can be grouped into micro-seismic and as small as hardly perceived by human beings. However, it should be noted that the current simulation was carried out using the highly simplified geometric model and assumptions such that the further simulations for a scheduled test production and commercial scale production considering complex geometric conditions may produce different results.

• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1110-1116
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• 2003

The effects of packaging methods on the storage quality of minimally processed (prepeeled) onions were investigated to determine the optimal packing design. Various packaging treatments used for modifying headspace atmospheres included two passive MAP using LDPE and PP films, two active MAP using a gas mixture of 20% $O_2/10%\;CO_2/balance\;N_2$ and an ethylene scavenging sachet, and moderate vacuum packaging (MVP). The quality attributes of onion samples were evaluated periodically in terms of flesh weight loss, color of cut surface, decay ratio, microbial counts, and sensory properties during storage at $10^{\circ}C$ for 28 days. Packaging methods did not significantly influence surface color, weight loss, and microbiological populations of mesophiles, psychrotrophs, and lactic acid bacteria. They did, however, affect sensory characteristics as well as decay occurrence. Results indicated that seal-packaging with a gas-permeable plastic film under a mild vacuum condition could retain better onion quality in terms of microbial decay and visual sensory aspects as compared with the other packages.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1999.05a
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• pp.45-45
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• 1999

일반 구조용 탄소강은 수용액 중에 노출될 때 부식에 의한 손상을 받기 쉽다. 부식의 양지를 위한 방법으로 사용 매체 중에 부식억제제를 첨가하여 탄소강의 부식속도를 낮추는 방법은 흔히 사용되는 방법이다. 부식억제제는 부식억제의 원리에 따라 양극부식억제제, 음극부식억제제 그리 고 이들의 혼합부삭억 세제 둥 여러 종류가 목적에 따라 사용되고 있다. 일반적으로 부식억제제의 성능 평가에는 무게감량볍, 표면분석법, 분극거동측정, 부석전위, 선 형분극법에 의한 부식속도 측정 등 다양한 방법이 시도되고 있다. 이 중에서 전기화학적 평가볍 은 부삭억제제의 작용 기구 규명 등을 위하여 많이 사용되고 있다. 한편 제품의 개발 단계에서 실질적인 평가법으로 갈리 사용하고 있는 방법은 무게 감량법인데 이 방법은 전면부식에 의한 금 속 손실량을 측정하여 부식억제능을 측정하는 방법이다. 그러냐 실제로 부삭억제제가 사용되고 있는 환경에서의 부식양상을 판찰하여보면 전면부식에 의한 손상보다는 국부부식에 의한 손상이 보다 치명적언 경우를 종종 목격할 수 있다. 이러한 관점에서 가존의 무게감량법은 한계가 있다. 따라서 본 연구에서는 이러한 국부부식을 보다 효과적으로 평가하기 위해 새로운 시험법을 도 입 상용 부식억제제의 종류별로 비교하였다. 부식억제제로는 수용액 중의 부식억제제로 널리 사용되고 있는 Nalco 39L과 본 연구실에서 SK해미칼과 공동 개발한 GH-110 등에 대하여 MCA(Multiple Crevice Assembly)를 이용 틈부식 저항성을 평가하였다. 또한 박막화된 전기저항형 부석속도 측정 센서를 틈부식 형태의 부식측정 에 적용하는 연구를 행하였다. 시험에 사용한 재갚는 천연가스의 감압 온도보상용으로 운전하는 가스히터의 주 구성 재료인 저탄소강을 사용하였으며 열화된 부식억제제 용액으로 사용기간이 서로 다른 수용액들에 대하여 평가 방법을 적용하여 비교하였다 다양한 부식억 제 제 수용액을 비교한 결과 MCA(Multiple Crevice Assembly)를 이용한 틈부식 억제능 시험은 실제 현장 사험 결과와 어느 정도 일치하는 결과를 보였다. 새로운 틈부식 저항성 측정법으로 시도한 철박막을 이용 틈부식 측정법은 육안 검사를 실시하지 않고도 틈부식의 전행 여부를 확인할 수 있는 가능성을 확인하였다.