• 한국추진공학회지
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• 제18권1호
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• pp.33-41
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• 2014

초음속 터빈에서는 동익 유로에서의 질식 가능성을 줄이며, 설계 압력비를 구현할 수 있도록 한다. 하지만 동익 오버랩을 적용하면, 펌핑손실, 확산손실 등의 추가적인 손실이 동반된다. 따라서 터빈성능을 극대화하기 위한 최적 오버랩 형상을 찾기 위해 근사최적화 기법을 적용하였다. 설계변수는 동익 오버랩의 형상변수이다. 최적설계 결과, 기준모델 대비 팁 누설유량은 약 50% 감소하였으며, 정효율은 약 4% 증가하였다. 팁 오버랩 크기가 성능에 미치는 영향이 크게 나타난 반면, 허브 오버랩 크기가 성능에 미치는 영향은 작게 나타났다.

• Asian-Australasian Journal of Animal Sciences
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• 제8권3호
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• pp.275-280
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• 1995

The effect of supplemented high protein diet intake on renal urea regulation in swamp buffalo was carried out in the present experiment Five swamp buffalo heifers weighing between 208-284 kg were used for this study. The animals were fed with a supplementary high protein diet and renal function and kinetic parameters for urea excretion were measured. This was compared to a control period where the same animals had been fed only with paragrass and water hyacinth. For 2 months the same animals were fed a mixed of paragrass, water hyacinth plus 2 kgs of a high protein supplement (protein 18.2% DM basis) per head per day. In comparison to the control period, there were no differences in the rate of urine flow, glomerular filtration rate (GFR), effective renal plasma flow (ERPF), plasma urea concentration and filtered urea. In animals supplemented with high protein intake mean values of urea clearance, excretion rate and the urea urine/plasma concentration ratio markedly increased (p < 0.05) while renal urea reabsorption significantly decreased from 40% to 26% of the quantity filtered. In this same study group urea space distribution and urea pool size increased which coincided with an increase in plasma volume (p < 0.05). Plasma protein decreased while plasma osmolarity increased (p < 0.05). Both urea turnover rate and biological half-life of $^{14}C$-urea were not affected by a supplementary high protein intake. The results suggest that animals supplemented with high protein diets are in a state of dynamic equilibrium of urea which is well balanced between urea excreted into the urine and the amount synthesized. The limitation for renal tubular urea reabsorption would be a change in extra-renal factors with an elevation of the total pool size of nitrogenous substance.

• 한국전자거래학회지
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• 제20권4호
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• pp.127-150
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• 2015

9/11사건 이후 인터넷이 테러활동을 위한 주요 공간으로 등장하였고, '외로운 늑대'들은 사이버 공간에서 각종 테러 도구를 구입하고, 급진의식화에 이용하고 있다. 이러한 측면에서 2015년 1월 발생한 김 모 군의 이슬람국가(IS) 가담은 우리사회가 더 이상 '테러청정국가'가 아니라는 점을 경각시켜 주는 것과 동시에 '외로운 늑대' 테러리스트 발생 가능성에 대한 체계적인 연구의 필요성을 제기하고 있다. 이에 본 논문은 다양한 선행 논문과 담당 수사관 및 전문가 면담을 통해 확보한 자료를 기초로 '외로운 늑대 사이버 진화모델'을 개발하고, '김 군'의 '외로운 늑대' 진화과정을 분석하였다. 나아가, 다문화 사회화 국제 이동인구 증가 소외계층 급증 이념갈등 심화 등 우리 사회의 외로운 늑대 동인이 될 수 있는 요소들을 분석하여 '외로운 늑대'의 추가 발생 가능성을 예측하였다. 결론 부분에서는 한국에서 '외로운 늑대' 테러 예방을 위한 효과적인 정책적 대안들에 대해 살펴보았다.

• 한국임상약학회지
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• 제11권1호
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• pp.1-6
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• 2001

This research is conducted to evaluate the clinical and economic benefits from therapeutic drug monitoring(TDM) service on vancomycin in a tertiary general hospital. Total 99 pairs of steady state peak and trough concentrations of vancomycin were obtained from 73 patients. To see the clinical benefits, the appropriateness of vancomycin dosing before TDM was evaluated. In 72 pairs of vancomycin blood concentrations obtained prior to TDM consultation, $47.2\%$ of the cases had reached within therapeutic range. Serum vancomycin levels in patients with $40{\leq}CLcr<60$ (ml/min) were higher and than the levels in patients with 40>CLcr and $60{\leq}CLcr$ (ml/min). Dose reduction rate in patients with creatinine clearance $40{\leq}CLcr<60$ (ml/min) were also significantly higher than those of compared groups ($61.5\%$, p=0.0138). Serum vancomycin concentrations were re-obtained from 21 patients who received modified dose through TDM service. Ninety percent (19/21cases) of them were within the target therapeutic range. For the evaluation of economic benefits from TDM consultation, estimated cost savings were calculated in those patients. The total drug saving were 586 vials in 21 patients. The calculated mean cost saving from the drugs was 314,570 won (range: $11,273\sim473,466)$ per patient. The study revealed that TDM service for vancomycin is necessary because empirical dosing is not effective for obtaining therapeutic drug level, especially patients with mild renal insufficiencies. The cost saving from TDM is also beneficial for the patients.

• 대한핵의학회지
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• 제8권1_2호
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• pp.13-24
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• 1974

The patterns of renogram in patients with Korean hemorrhagic fever were evaluated with clinical course and renal hemodynamic changes in various clinical stages. The renal plasma flow was measured by hippuran blood clearance using $^{131}I$-ortho-iodohippurate and hippuran renogram was analysed by means of quantitative and qualitative methods in 26 patients of Korean hemorr hagic fever. The results obtained with this study were as follows; 1. During the oliguric phase of Korean hemorrhagic fever, the renogram showed non-functioning (flat) or obstructive pattern. The group of patients with non-functioning pattern of renogram had more severe impairement of renal function and grave prognosis than the group with obstructive pattern of renogram. 2. During the diuretic phase, the renogram showed obstructive or dysfunction or normal pattern, which was related with the recovery of renal function. Obstruction pattern of renogram was observed till the 2nd week of diuretic phase. Normal pattern of renogram began to appear by the 2nd week of diuretic phase. 3. During the convalescent phase of Korean hemorrhagic fever, 40% of patients showed dysfunnction pattern of renogram, and the recovery of abnormal renogram in Korean hemorrhagic fever was more delayed than the recovery of clinical features and laboratory findings. 4. The renogram showed normal pattern 6 months after onset of Korean hemorrhagic fever in all cases. 5. There was significant correlationship between the pattern of renogram and the decreace of renal plasma flow in the patients with Korean hemorrhagic fever. The decreace of renal plasma flow was maked in the patients with non-functioning pattern of renogram and was least in the patients with dysfunction pattern of renogram. All above results suggested that the renogram reflects the effective renal plasma flow and degree of renal impairement, and the renogram may be one of the important indexes which could give us a more precise prognosis in Korean hemorrhagic fever.

• Tribology and Lubricants
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• 제32권1호
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• pp.1-8
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• 2016

This paper focuses on the thermal deformation induced preload change in the tilting pad journal bearing, using a three-dimensional (3D) thermo-hydro-dynamic (THD) approach. Preload is considered as a critical factor in designing the tilting pad journal bearing. The initial preload measured under nil external load and nil thermal gradient is influenced by two factors, namely, the thermal deformation and elastic deformation. Thermal deformation is due to a temperature distribution in the bearing pads, whereas the elastic deformation is due to fluid forces acting on the pads. This study focuses on the changes induced in preload and film clearance due to thermal deformation. The generalized Reynolds equation is used to evaluate the force of the fluid and the 3D energy equation is used to calculate the temperature of the lubricant. The abovementioned equations are combined by establishing a relationship between viscosity and temperature. The heat transfer within the bearing pads, the lubricant, and the spinning journal is calculated using the heat flux boundary condition. The 3D Finite Element Method (FEM) is used in modeling the (1) heat conduction in the spinning journal and bearing pads, (2) thermal gradient induced thermal distortion of the spinning journal and pads, and (3) viscous shearing, and heat conduction and convection in a thin film. This evaluation method has an increased fidelity, and it can prove to be a cost-effective tool that can be used by designers to predict the dynamic behavior of a bearing.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2011년도 춘계학술발표회 논문집
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• pp.81-91
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• 2011

Current fuel ethanol research and development deals with process engineering trends for improving biotechnological production of ethanol. Recently, a large amount of studies regarding the utilization of lignocellulosic biomass as a good feedstock for producing fuel ethanol is being carried out worldwide. The plant biomass is mainly composed of cellulose, hemicellulose and lignin. The main challenge in the conversion of biomass into ethanol is the complex, rigid and harsh structures which require efficient process and cost effective to break down. The isolation of microorganisms is one of the means for obtaining enzymes with properties suitable for industrial applications. For these reasons, crude cultures containing cellulosic biomass degrading microorganisms were isolated from rice field soil, cow farm soil and rotten rice straw from cow farm. Carboxymethyl cellulose (CMC), xylan and Avicel (microcrystalline cellulose) degradation zone of clearance on agar platefrom rice field soil resulted approximately at 25 mm, 24 mm and 22 mm respectively. As for cow farm soil, CMC, xylan and Avicel degradation clearancezone on agar plate resulted around at 24mm, 23mm and 21 mm respectively. Rotten rice straw from cow farm also resulted for CMC, xylan and Avicel degradation zone almost at 24 mm, 23 mm and 22 mm respectively. The objective of this study is to isolatebiomass degrading microbial strains having good efficiency in cellulose hydrolysis and observed the effects of different substrates (CMC, xylan and Avicel) on the production of cellulase enzymes (endo-glucanase, exo-glucanase, cellobiase, xylanase and avicelase) for producing low cost biofuel from cellulosic materials.

• Tribology and Lubricants
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• 제30권1호
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• pp.9-14
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• 2014

In this Part II study, rotordynamic stability analyses were carried out to confirm improvements to the stability of a process high-speed lightweight centrifugal compressor, depending on the effects of tilting pad journal bearing designs. The bearing design variables considered were the clearances, LBPs, LOPs, and preloads. The results showed that the rotordynamic stability of the subject compressor rotor-bearing system improves exactly in accordance with the effects of the bearing design variables, which were determined in the preceding Part I study, owing to reduced bearing stiffnesses. Specifically, it was confirmed that the stability of the rotor system can be greatly improved by increasing both the machined and assembled bearing clearances, but there were no stability improvements by simply changing from an LBP to an LOP design. In addition, it was confirmed that for given fixed machined bearing clearances, the stability can be additionally improved by decreasing the preloads, i.e., by increasing the assembled clearances. In conclusion, it may be necessary to improve the designs of the original tilting pad bearings to obtain a sufficient margin of rotordynamic stability against a possible aerodynamic cross-coupled stiffness in a process high-speed centrifugal compressor. Thus, increasing the machined and assembled bearing clearances and decreasing the preload could be effective solutions.

• 한국해양공학회지
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• 제24권6호
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• pp.76-80
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• 2010

Oil hydraulic piston pumps are being extensively used around the world, because of their simple design, light weight, effective cost, etc. An oil hydraulic pump is likely to have the serious problems of high leakage, friction, and low energy efficiency after a long period of use. In an oil hydraulic piston pump, the clearance between the valve block and piston plays an important role for volumetric and overall efficiency. In this study, the wear property of the SACM645 material with DLC coating used for a hydraulic piston pump was determined by experimentation with variable heat treatment. To investigate the effect according to the piston surface condition, five different types of specimens were prepared. The maximum tensile strengths of the QT and QT Nitration specimens had similar values of about 800 MPa, but the strains indicated a big difference. In a wear test, the wear characteristic of the DLC coating specimen was shown to be excellent. The QT, QT + IH, QT + Nitration, and matirx specimen showed similar wear characteristics. In the case of a dry condition without oil, the DLC coating specimen had good wear resistance, with no wear shown.

• 대한인간공학회지
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• 제29권3호
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• pp.383-391
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• 2010

The present study evaluated a preliminary control room (CR) design of radioactive waste facility using the $JACK^{(R)}$ human simulation system. Four digital humanoids ($5^{th}$, $50^{th}$, $95^{th}$, and $99^{th}$ percentiles) were used in the ergonomic evaluation. The first three were selected to represent 90% of the target population (Korean males aged 20 to 50 years) and the last to reflect the secular trend of stature for next 20 years in South Korea. The preliminary CR design was assessed by checking its compliance to ergonomic guidelines specified in NUREG-0700 and conducting an in-depth ergonomic analysis with a digital prototype of the CR design and the digital humanoids in terms of postural comfort, reachability, visibility, and clearance. For identified design problems, proper design changes and their validities were examined using JACK. A revised CR design suggested in the present study would contribute to effective and safe operations of the CR as well as operators' health in the workplace.