• 상하수도학회지
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• 제28권2호
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• pp.161-170
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• 2014

It is essential to decrease energy consumption and excess sludge to economically operate sewage treatment plant. This becomes more important along with a ban on sea dumping and exhaustion of resource. Therefore, many researchers have been study on energy consumption reduction and strategies for minimization of excess sludge production from the activated sludge process. The aeration cost account for a high proportion of maintenance cost because sufficient air is necessary to keep nitrifying bacteria activity of which the oxygen affinity is inferior to that of heterotrophic bacteria. Also, additional costs are incurred to stabilize excess sludge and decrease the volume of sludge. There were anoxic, aerobic, membrane, deairation and concentration zone in this MBR process. Continuous aeration was provided to prevent membrane fouling in membrane zone and intermittent aeration was provided in aerobic zone through ammonia sensor. So, there was the minimum oxygen to remove $NH_4-N$ below limited quantity that could be eliminated in membrane zone. As the result of this control, energy consumption of aeration system declined by between 10.4 % and 19.1 %. Besides, we could maintain high MLSS concentration in concentration zone and this induced the microorganisms to be in starved condition. Consequentially, the amount of excess sludge decrease by about 15 %.

• Journal of Korean Neurosurgical Society
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• 제40권6호
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• pp.406-411
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• 2006

Objective : The authors have developed a procedure, termed posterior microscopic lesionectomy, that creates a minimal laminotomy site according to the location of the shifted disc using the $METRx^{TM}$ system in the lumbar spine. This study compared the usefulness and surgical outcomes of this procedure with those of traditional standard lumbar discectomy. Methods : From June 2003 to June 2004, Twenty-two patients with one-level radiculopathy due to lumbar disc herniation underwent posterior microscopic lesionectomy with the assistance of an operating microscope and the $METRx^{TM}$ tubular retractor. Surgical results of the new procedure were compared to those of 39 patients who underwent traditional lumbar discectomy from April 2003 to September 2004. All patients were evaluated for pain score, clinical assessment according to the VAS, and Roland-Morris scores pre-operatively and at 1, 3, 6, and 12 months post-operatively. Results : Mean blood loss, operation time, and admission date showed significant improvements for microscopic lesionectomy compared to traditional lumbar discectomy [P < 0.001]. Also, both measures of short-term functional improvement, the Visual Analogue Scale[VAS] and Roland-Morris[RM] scores, were statistically better for microscopic lesionectomy than for traditional discectomy [P < 0.001]. Conclusion : Posterior microscopic lesionectomy can be performed more safely and provide greater benefit than traditional discectomy. The procedure is associated with less post-operative pain, shorter hospital stays, and quicker rehabilitation.

• Journal of Korean Neurosurgical Society
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• 제48권3호
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• pp.219-224
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• 2010

Objective : A minimally invasive transforaminal lumbar interbody fusion (MIS TLlF) has recently been introduced. However, MIS TLlF is a technically challenging procedure. The authors performed retrospective analysis about MIS TLlF using a single interbody cage. Methods : Twenty-eight consecutive patients were treated by MIS TLlF. Of these 28 patients, 20 patients were included in this retrospective study. Perioperative, clinical, and radiologic outcomes were assessed. Clinical outcomes were assessed using Oswestry Disability Index (ODI) and Visual Analogue Scores (VAS). Fusion rates and cross-sections of operated spinal canals were assessed by CT. Results : Twelve patients underwent MIS TLlF at one segment and 8 patients at two segments (L3/4: 4, L4/5: 17, L5/S1: 7). Operation time for a single segment was 131.7 min and for two segment was 201.4 min, and corresponding blood losses were 208.3 mL and 481.2 mL, respectively. ODI and VAS scores were significantly improved at 6 months postop (ODI from 30.32 to 15.54, VAS from 7.80 to 2.20, p = 0.001) Twenty-two segments (78.6%) achieved grade I fusion, 4 segments (14.3%) achieved grade II, 2 segments (7.1%) achieved grade III and 0 segments achieved grade IV at 12 months. Postoperatively at 12 months, spinal canal cross sectional areas at disc spaces significantly increased from 157.5 to $294.3\;mm^2$ (p = 0.012). Conclusion : MIS TLlF achieved good clinical outcomes and high fusion rates. Our findings show that MIS TLlF performed with a single Interbody cage and a tubular retractor system can be used as a standard MIS TLlF technique.

• 한국추진공학회지
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• 제15권6호
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• pp.47-55
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• 2011

본 논문에서는 매니폴드 내의 튜브 라운드 적용에 따른 고온 고압 튜브형 열교환기에서의 압력강하와 열성능을 분석하기위해 전산해석을 수행하였다. 튜브형 열교환기에서의 압력강하와 열성능은 튜브라운드의 위치에 많은 영향을 받는다. 튜브 라운드에 따른 연구는 튜브 입구, 튜브 출구, 그리고 튜브 양쪽 세 가지 위치에 따라 수행하였다. 본 연구에서, 튜브 양쪽에 라운드를 적용한 경우에는 가장 낮은 압력강하와 감소된 열전달을 보였지만 튜브 출구에 라운드를 적용한 경우에는 압력강하와 열전달 모두 기본형상에 비하여 좋은 특성을 보였다.

• Parasites, Hosts and Diseases
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• 제29권1호
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• pp.43-54
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• 1991

폐홉충(Paragonimus westermani) 초기 감염시의 숙주 면역 기전을 알아보기 위하여 폐흡충 피낭유충을 백서에 감염시켜 주별(주별)로 항혈청을 분리하고 등일 백서에서 복강 대식세포(homologous rat peritoneal macrophage)를 얻은 다음, 이들과 폐흡충 탈낭유충 및 숙주 조직 이행중인 유약충으로 effector system을 조작하여 폐흡충 유충에 대한 항체 의존성 대식세포 공격기전을 관찰하였다. 백서 복강 대식세포는 항혈청 출현 시에만 폐흡충 탈낭유충에 대한 세포부착 반응(cell adherence reaction)을 보였고 이 반응에는 보체가 관여하지 않았다. 폐흡충 감염 1주에서 8주까지의 백서 항혈청 중 2주째에 분리한 항쳔청 실험군에서 100%의 세포부착 반응을 나타내었고 사멸된 충체를 관찰할 수 있었으며, 세포부착 반응은 탈낭 유충기에서만 나타나는 반면 조직이행 유약충에서는 전혀 그 반응을 인정할 수 얼어 폐흡충 감염에 따른 항체의존성 숙주 세포 매개독성(antibodydependent cell·mediated cytotoxicity)은 발육단계 별 특이성을 보였다. 한편, 대식세포의 공격에 의하여 사멸된 폐흡충 탈낭유충의 형태학적 특징은 대식세포와 유충 사이에 형성되는 fuzzy material, tegumental syncytium 내의 미세구조의 변성 및 syncytium과 근육층을 연결하는 tubular tunnel의 형성 등이었다.

• Journal of Korean Neurosurgical Society
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• 제56권3호
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• pp.237-242
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• 2014

Objective : The purpose of this study was to investigate the clinical features and outcomes of pediatric cavernous malformation (CM) in the central nervous system. Methods : Twenty-nine pediatric patients with supratentorial CM underwent microsurgical excision. In selected cases, transparent tubular retractor system (TTRS) was used to reduce retraction injury and intraoperative neuromonitoring (IONM) was held to preserve functioning cortex. Patients' demographics and symptoms were reviewed and surgical outcomes were discussed. Results : The main initial clinical manifestations included the following : seizures (n=13, 45%), headache (n=7, 24%), focal neurological deficits (n=3, 10%), and an incidental finding (n=6, 21%). Overt hemorrhage was detected in 7 patients (24%). There were 19 children (66%) with a single CM and 10 (34%) children with multiple CMs. In 7 cases with deep-seated CM, we used a TTRS to minimize retraction. In 9 cases which location of CM was at eloquent area, IONM was taken during surgery. There was no major morbidity or mortality after surgery. In the 29 operated children, the overall long-term results were satisfactory : 25 (86%) patients had no signs or symptoms associated with CMs, 3 had controllable seizures, and 1 had mild weakness. Conclusion : With the assistance of neuronavigation systems, intraoperative neuromonitoring, and TTRS, CMs could be targeted more accurately and excised more safely. Based on the satisfactory seizure outcome achieved, complete microsurgical excision in children is recommended for CMs presenting with seizures but removal of hemosiderin-stained areas seems to be unnecessary.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
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• pp.21-24
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• 2005

Three dimensional circular braided Glass/Aramid hybrid fabric/epoxy resin composite was fabricated. FBG sensor was embedded along the braid yam in order to monitor the internal dimensional changes of the 3-D braid composite. The amount of cure and thermal shrinkage of epoxy resin was also determined using FBG sensor system. FBG sensors with different grating length were embedded and their response were compared. The thermo-optic coefficient of FBG sensor was measured by several preliminary experiments. The internal strain that measured by FBG sensor and electric strain gauge was compared during compressive test. The released residual strain of the fabricated tubular composite was estimated using cutting method. The internal strain of the composite was estimated using FBG sensor system, and the result was compared with the value from electric strain gauge. It was found that FBG sensor system is a very useful technique to investigate inside region of complicated structure.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2002년도 학술대회논문집
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• pp.191-196
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• 2002

In this paper we introduce novel electrode structure for high efficiency discharge. We operate discharge tube under the 0.16 torr pure Xe and apply the sinusoidal wave power to the lamp with 60kHz. We measure the electric power dissipation, plasma parameters, and 828 nm IR intensity. From these data we determine the discharge efficiency, IR intensity/watt, EEDF(Electron energy distribution function). As a result we obtain that the novel electrode structure has better performance in efficiency than that of conventional external electrode system. Also we determine the EEDF for each type of electrode structure by Boltzmann stover, EELNDIF code. The result of Boltzmann equation solving show that the noble electrode system has many high energy electrons compared with the conventional system.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.130.2-130.2
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• 2011

The application of solar energy in residential building is general and natural in today. And application methods of solar thermal energy is divided in two kind of form, single evacuated tube and flat-plate form. Then in this study, the efficiency of single evacuated tube and flat-plate system is compared by total and effective area considering the time receiving the solar radiation between 24 hours and the specific time(10:00~15:00). As a result of the experiment, single evacuated tube and flat-plate collector's efficiency is varied by the quantity of solar radiation. And especially, the flat-plate system is more affected by outdoor temperature. Therefore the application of solar thermal system should be considered the solar radiation and outdoor temperature.

• 설비공학논문집
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• 제3권4호
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• pp.231-240
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• 1991

A design method has been developed for a Stirling engine with a tubular heater and cooler and a screen type regenerator. This paper provides a design procedure to determine the thermodynamic states and the geometric configurations of the Stirling engine for residential heat pumps. The major design is concerned with the working spaces, i.e. compression and expansion spaces and the heat exchangers such as the heater, the cooler and the regenerator. The Schmidt analysis has been employed to obtain the mass flow rates and heat transfer requirements of the system. The performance analysis of a model Stirling engine was performed by Martini-Weiss program to prove the validity of this design method. The results obtained indicate that this design method is valid for the Stirling engine conceptual design and performance analysis.