• Journal of Chest Surgery
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• v.11 no.1
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• pp.81-84
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• 1978

A 15 years Old girl was admitted with chief complaints of intermittent claudication of lower extremity, dizziness, and headache for 5 years. On admission, malignant hypertension was noted in the upper part of body [190-150/120-110] but femoral & dorsalis pedis pulse could not palpate. Once she had experienced C. V. A. due to hypertension of upper part, about years ago. On auscultation, systolic murmur was audible along the left sternal border. E.C.G. Showed left ventricular hypertrophy pattern, and others within normal limit. Retrograde aortography demonstrated diffuse narrowing of entire thoracic aorta with underdeveloped lower abdominal aorta [below the renal artery] & both common lilac artery, and rich collaterals, but normally visualized greater arteries in the aortic arch. On left posterolasteral thoracotomy, entire descending thoracic aorta revealed marked narrowing with mild perivascular adhesion, but no mediastinal pleura adhesion. These findings suggest as congenital type of atypical coarctation in the entire thoracic aorta with mild secondary change. But histopathology was showed the findings of chronic non-specific aortitis, later. Dacron by pass graft was performed with end to side anastomosis between graft and aortic wall. After operation, all her preoperative symptoms & signs were disappeared, and discharged with good general condition.

• Membrane and Water Treatment
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• v.3 no.3
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• pp.141-149
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• 2012

The aeration provided in a Submerged Membrane Bioreactor (SMBR) improves membrane filtration by creating turbulence on the membrane surface and reducing membrane resistance. However, conventional hollow fiber membrane modules are generally packed in a vertical orientation which limits membrane scouring efficiency, especially when aeration is provided in the axial direction. In the present research, 3 innovative hollow-fiber membrane modules, each with a different membrane orientation, were developed to improve membrane scouring efficiency and enhance permeate flux. Pilot testing was performed to investigate the permeate flux versus time relationship over a 7-day period under different intermittent modes. The results indicated that the best module experienced an overall permeate flux decline of 3.3% after 7 days; the other two modules declined by 13.3% and 18.3%. The lower percentage of permeate flux decline indicated that permeate productivity could be sustained for a longer period of time. As a result, the operational costs associated with membrane cleaning and membrane replacement could be reduced over the lifespan of the module.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.529-533
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• 2012

By introducing RPS(Renewable Portfolio Standard) for reduction of greenhouse gas, Renewable energy sources have becoming widespread gradually. However, Renewable energy sources, such as wind power and PV are difficult to control the output and they have intermittent characteristics of the output. These characteristics would cause some problems when it is connected in the power system. In order to solve these problems, Energy Storage Systems(ESS) are considered to use. Although there are many different storage devices, the utilization of Secondary Battery is the one of the best ways to stabilize an output fluctuation of RES because of its fast responsibility. For that reason, it would better fit a large-capacity of Secondary battery for stabilization. However, batteries cannot be installed with a large capacity blindly because of its expensive cost. So to select proper capacity of the battery is an important consideration. This paper presented a methodology for the optimal capacity and operation of ESS in microgrids.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.8
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• pp.1056-1061
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• 2000

Particles existing in a hard disk drive are known as a major source of TA(thermal asperity). Researchers have investigated how particles induce the TA phenomena, but have not verified yet the reason why and how particles are generated in a HDD. The objective of this study is to investigate why and how particles are generated, and in what condition, the largest number of particles is generated. The number of particles generated in a HDD was measured over the landing zone after various rest times of slider and during various motions and positions of slider. It is found that the large number of particles was generated when the HDD was turned on after a long rest time of slider and that a few of particles were continuously generated when the slider flied over the disk surface. It is thought that the number of particles generated in a HDD was related to the rest time of slider because the rest time of slider increased stiction, and that there were intermittent contacts between the slider and the disk surface when the slider flied over the disk surface.

• Journal of Drive and Control
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• v.12 no.4
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• pp.71-76
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• 2015

The therapy of injecting a fixed amount of a prescribed drug for a predetermined time is an effective treatment in relieving pain during anticancer treatments. Due to recent medical technology development, cancer is currently classified as a disease that can be managed in the patient's lifetime. If patients were able to use a drug delivery system that was portable, sustainable and had an accurate flow control, they would be able to inject medication whenever they need. In this study we developed a piezoelectric micropump for a drug delivery system by designing a pump chamber, check valve and diaphragm. We also developed a driving circuit that consumes low power and to which we applied a variety of signals. We fabricated a portable drug delivery system with this piezoelectric micropump and driving circuit. In addition, through a performance test, we confirmed that the system can precisely control the drug flow rate.

• Journal of Korean Neurosurgical Society
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• v.46 no.4
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• pp.413-416
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• 2009

Since the start of the antibiotic era, syphilis has become rare. However, in recent times, it has tended to be prevalent concomitantly with human immunodeficiency virus (HIV) infection and coinfection in North America and Europe. Now, such cases are expected to increase in elsewhere including Korea. A 40-year-old male patient visited hospital complaining of a headache for about one month. Brain computed tomography and magnetic resonance imaging, showed leptomeninged enhancing mass with edema an right porisylvian region, which was suspected to be glioma. Patient underwent a blood test and was diagnosed with syphilis and acquired immune deficiency syndrome. Partial cortical and subcortical resection were performed after small craniotomy. The dura was thick, adhered to the brain cortex, and was accompanied by hyperemic change of the cortex. The pathologic diagnosis was meningovascular syphilis (MS) in HIV infection. After the operation, the patient was treated with aqueous penicillin G. Thereafter, he had no neurological deficit except intermittent headache. At first, this case was suspected to be glioma, but it was eventually diagnosed as MS in HIV coinfection. At this point the case was judged to be worth reporting.

• Journal of Chest Surgery
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• v.19 no.3
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• pp.412-420
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• 1986

From 1968 through September 1986, the authors have experienced 34 cases of peripheral arterial surgery using various vascular grafts. Almost all patients [32] were men, and age distribution was variable according to the disease entities. There were twenty eight cases of chronic occlusive peripheral vascular disease including ASO [21], Buerger`s disease [6], Aortoenteric fistula complicating infrarenal abdominal aortic aneurysm [1], four cases of vascular trauma, one case of acute arterial embolism [1] and one case of unknown etiology. The indications of operations for chronic vascular disease was intermittent claudication in 48%, rest pain in 45%, ischemic pregangrene or gangrene in 28%, and sensory change in 10% of patients. Types of operation used were arterial bypass in 28 cases [Aortobifemoral in 5, Aortoiliac in 3, Aortofemoral in 4, Aortoiliac with Aortofemoral in 1, Femorofemoral in 1, Femoropopliteal in 8, Femoroperoneal in 2, Axillofemoral in 3 cases of patients], graft interposition in four and patch angioplasty in three cases. Thirty four prosthetic vascular grafts including Dacron, Gore-Tex, Nylon and two autogenous saphenous vein graft and patch were used for vascular reconstruction in thirty four patients. Unfortunately recently performed one vein bypass was failed immediate postoperatively due to severity of disease and poor case selection. The authors experienced five post operative complications: wound infection [1], graft infection [1], bleeding [1], great saphenous neuralgia [1], pseudoaneurysm [1]. Twenty two of thirty four patients were followed up for more than one month and their cumulative patency rate was 81% [17/22] at 1 month and, 31% [7/22] at 5 month.

• Nuclear Engineering and Technology
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• v.45 no.5
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• pp.581-588
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• 2013

This paper deals with the Safety Analysis for $CANDU^{(R)}$ 6 nuclear reactors as affected by main Heat Transport System (HTS) aging. Operational and aging related changes of the HTS throughout its lifetime may lead to restrictions in certain safety system settings and hence some restriction in performance under certain conditions. A step in confirming safe reactor operation is the tracking of relevant data and their corresponding interpretation by the use of appropriate thermal-hydraulic analytic models. Safety analyses ranging from the assessment of safety limits associated with the prevention of intermittent fuel sheath dryout for a slow Loss of Regulation (LOR) analysis and fission gas release after a fuel failure are summarized. Specifically for fission gas release, the thermal-hydraulic analysis for a fresh core and an 11 Effective Full Power Years (EFPY) aged core was summarized, leading to the most severe stagnation break sizes for the inlet feeder break and the channel failure time. Associated coolant conditions provide the input data for fuel analyses. Based on the thermal-hydraulic data, the fission product inventory under normal operating conditions may be calculated for both fresh and aged cores, and the fission gas release may be evaluated during the transient. This analysis plays a major role in determining possible radiation doses to the public after postulated accidents have occurred.

• Journal of Yeungnam Medical Science
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• v.2 no.1
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• pp.253-258
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• 1985

The congenital tracheoesophageal fistula without atresia of the esophagus is considered a rare variant, and the literature concerned to the tracheoesophageal fistula without atresia, is little in adult especially. The 22-year-old male was admitted to Yeungnam University Hospital with his chief complaints of weight loss (6kg/6 months), abdominal discomfort, and intermittent coughing. The diagnosis was made by the endoscopy and esophagography. The fistula was 1.5cm in diameter, 0.5cm in length. The level was around second thoracic vertebra. The operation was performed transpleurally through the right third intercostal space and the fistula was secured with interrupted silk suture after division. The fibrotic adhesion was seen around the tracheoesophageal fistula. The postoperative course was uneventful, and postoperative esophagogram revealed ho extraluminal leakage. Herewith we report this unusual case of isolated tracheo-esophageal fistula with review of literatures.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.3
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• pp.486-492
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• 2017

In recent years, renewable energy sources have been mentioned as solution to environmental regulation and energy supply-demand. Energy storage systems are needed to mitigate the intermittent output characteristics of renewable energy sources and to operate micro grid efficiently using renewable energy generation systems. However, despite the necessity of energy storage system, this cannot secure the economical efficiency of the energy storage system by high initial cost. In this paper, a micro grid is constructed to supply electric power to industrial customers by using solar power generation system and energy storage system among renewable energy generation power sources and operated to improve energy independence. In the case study, we use photovoltaic system which is representative renewable energy generation system. Unlike conventional photovoltaic system, this system uses floating photovoltaic system with the advantage of having high output and no land area limitations. It is operated for the purpose of improving energy independence in the micro grid. In order to secure economical efficiency, the energy storage system operates a micro grid with a minimum capacity. Finally, this paper calculates the appropriate subsidy for the energy storage capacity.