• 한국자동차공학회논문집
• /
• 제3권3호
• /
• pp.9-18
• /
• 1995

The substitution of conventional fuel oil by alternative fuels is of immense interest due to liquid oil shortage and requirements of emission control standard. Among the alternative fuels, natural gas may be the most rational fuel, because of its widespread resource and clean est burning. Meanwhile, engine simulation is of great importance in engine development. Hence a zero-dimensional combustion model was developed for dual-fuel system. Natural gas was injected directly into the cylinder and small amount of distillate was used to provide the ignition kernel for natural gas burning. The intake air and exhaust gas flow was modeled by filling and emptying method. Although the single zone approach has an inherent limitation, the model showed promise as a predictive tool for engine performance. Its simulation was also made to see how the engine performance was influenced by the fuel injection timings and amount of each fuel.

• 대한핵의학회지
• /
• 제28권1호
• /
• pp.52-61
• /
• 1994

Background : The demand for refinement in noninvasive and quantitative assessment of left ventricular (LV) function is increasing. Purpose : To assess normal values of left ventricular functional parameters during both systole and diastole by scintigraphic method using computerized triple-head gamma camera and to evaluate correlations between these parameters. Methods : ECG gated blood pool scan with $^{99m}Tc$-Human serum albumin was performed in 94 normal Korean subjects. Ejection fraction (EF), systolic parameters [peak emptying rate (PER), average emptying rate (AER), time to peak emptying rate (TPER)], and diastolic parameters [peak filling rate (PFR), average filling rate (AFR), time to peak filling rate (TPFR)] were obtained by analysis of LV time-activity curve, the correlation of these parameters to the age and sex, and the correlation between these parameters were evaluated. Results : 1) Mean value of ejection fraction in study subjects was $59.6{\pm}5.25%$ and showed no significant correlation to age (r=-0.08) and sex but showed most pronounced correlation to PFR (r=0.46, p<0.001), PER (r=0.41, p<0.001), AFR (r=0.34, p<0.001) and AER (r=0.28, p<0.01). 2) Mean values of systolic parameters were as follows: $PER=3.22{\pm}0.50$ end-diastolic volume/sec, $AER=2.22{\pm}0.45$ end-diastolic volume/sec, $TPER=103.5{\pm}29.30$ msec. They showed no significant correlation to age and sex. 3) Mean values of diastolic parameters were as follows: $PFR=2.71{\pm}0.51$ end-diastolic volume/sec, $AFR=1.83{\pm}0.44$ end-diastolic volume/sec, $TPFR=132.1{\pm}33.45$ msec. They showed strong correlation to age (r=0.70, -0.64, 0.37, p<0.001). Conclusions : Left ventricular functional parameters in normal Korean subjects were obtained reliably by computerized scintigraphic method and may be applied to the evaluation of cardiac function in diseased patients.

• 대한기계학회논문집
• /
• 제19권3호
• /
• pp.796-805
• /
• 1995

For the purpose of improving performances of a turbocharged diesel engine at low speed, this study investigates the effects of the injected air for the performances and flow characteristics in the intake and exhaust pipes by using the computer simulation with test bed. In the theoretical analysis, the whole flow system, including engine cylinders and intake and exhaust pipes, is calculated numerically by the method of filling and emptying. From the results of this study, the following conclusions may be summarized. Increasing injected air pressure into the pipe of compressor exit brings about the improvement in a performance and flow characteristics of intake and exhaust pipes under full load operating conditions at 1000 rpm of the engine speed, but shows trends of the inferior performances under no load operating conditions at 2000 rpm of the engine speed.

• 한국의류산업학회지
• /
• 제11권1호
• /
• pp.24-32
• /
• 2009

The purpose of this study is to understand characteristic of expression in Korean style fashion design and investigated Korean style fashion design's deployment and design idea method as well as its esthetic value. The photographs for the research were selected from fashion collections during S/S 2003-F/W 2007 by four specialists in the department of textile and then analyzed with 288 final data. The results were as followings. First, the characteristics of design expression in Korean style fashion design were formation by separating partial shape from the whole, formation by shape's separation and repetition, and connecting formation by combination and transformation of parts. In the case of color, they were direct expression, contrasting formative expression, and gradual changing expression. In the case of pattern, they were the methods of filling, filling & emptying, and partial filling. Second, the deployments of Korean style fashion design were adding modern elements to traditional things, combining traditional elements and modern things, and adding traditional elements to modern things. The third, Korean style fashion design's idea methods were weaving, snatching, adding, and changing. Fourth, it was shown that esthetic values of Korean style fashion design were the interactive organism by building organic relationship, the optimum expressing beauty with minimum elements, the palpitation having dynamics and rhythmical beauty.

• Journal of Advanced Marine Engineering and Technology
• /
• 제34권1호
• /
• pp.62-68
• /
• 2010

대기오염 및 지구온난화와 관련하여 디젤기관의 친환경, 고효율에 대한 요구가 선박기관에도 강화되고 있다. 이와 관련하여 많은 새로운 기술들이 연구, 적용되고 있으나, 이들은 주로 신조선에 관심이 집중되어 있다. 선박은 건조된 후 비교적 장기간 이용되기 때문에 이미 운항중인 현존선에 대하여도 이에 관한 연구가 필요하다고 판단되며 이는 주로 엔진성능의 개선에 관한 연구가 될 것이다. 이 논문은 선박용 2행정 디젤기관의 성능을 시뮬레이션 하기위한 프로그램을 개발한 결과를 보고한다. 현존선의 엔진성능은 운전시간의 경과에 따라 열화되어 가기 때문에 엔진의 열화성능을 예측할 수 있도록 한 것이 본 연구에서 개발된 프로그램의 특징이다. 예측결과는 엔진메이커에서 사용하고 있는 TOP-CODE 프로그램의 계산결과와 비교하였으며, 양호한 결과를 보이고 있음을 확인하였다.

• 성인간호학회지
• /
• 제26권6호
• /
• pp.630-641
• /
• 2014

Purpose: The purpose of current study was to explore the positive outcomes of advanced practice nurse who have experienced the roles in their clinical settings. Methods: This study adopted a qualitative research design based on conventional content analysis. Participants were 16 nurse practitioners have been worked at hospitals or community centers. Data were collected via focus group interviews and analyzed using thematic analysis method. Results: Patients' aspect outcomes were "client-centered care in providing continuity", "providing trust based on expertise", "promoting skilled intervention in patient recovering", "blocking the negative consequences", "quality improvement: nursing becoming tighter", "providing total care for cases that require intensive care", "improving patients outcomes by total management", "increasing confidence in evidence-based professional nursing", "rising the satisfaction by cost-effective services", "providing skilled professional practice", and "providing comprehensive care related to covering various aspects". Other themes elicited also included "promoting efficacy by inter-related health professions supervising", "the expansion of specialized practice areas increase business efficiency", "formation of outside customers due to increasing the satisfaction with skilled nursing care", "filling in the emptying spaces of doctors by practicing reliable role to bridge", "attracting external customers through successful management of subjects", "increasing staff's satisfaction on the role to make a bridge between inside and outside doctors", "24 hours medical expertise of professional staff ready secured", and "low cost, same results, that is, cost-effective" in reference to health care resources aspect. Conclusion: These findings suggested that advanced practice nurses perceived various positive outcomes and provided basic data for outcome indicators of advanced practice nurses' role.

• 대한비뇨기종양학회지
• /
• 제15권3호
• /
• pp.178-186
• /
• 2017

Purpose: Poloxamer 407 (P407) thermo-sensitive hydrogel formulations were developed to enhance the retention time in the urinary bladder after intravesical instillation. Materials and Methods: P407 hydrogels (P407Gels) containing 0.2 w/w% fluorescein isothiocyanate dextran (FD, MW 4 kDa) as a fluorescent probe were prepared by the cold method with different concentrations of the polymer (20, 25, and 30 w/w%). The gel-forming capacities were characterized in terms of gelation temperature (G-Temp), gelation time (G-Time), and gel duration (G-Dur). Homogenous dispersion of the probe throughout the hydrogel was observed by using fluorescence microscopy. The in vitro bladder simulation model was established to evaluate the retention and drug release properties. P407Gels in the solution state were administered to nude mice via urinary instillation, and the in vivo retention behavior of P407Gels was visualized by using an in vivo imaging system (IVIS). Results: P407Gels showed a thermo-reversible phase transition at $4^{\circ}C$ (refrigerated; sol) and $37^{\circ}C$ (body temperature; gel). The G-Temp, G-Time, and G-Dur of FD-free P407Gels were approximately $10^{\circ}C-20^{\circ}C$, 12-30 seconds, and 12-35 hours, respectively, and were not altered by the addition of FD. Fluorescence imaging showed that FD was spread homogenously in the gelled P407 solution. In a bladder simulation model, even after repeated periodic filling-emptying cycles, the hydrogel formulation displayed excellent retention with continuous release of the probe over 8 hours. The FD release from P407Gels and the erosion of the gel, both of which followed zero-order kinetics, had a linear relationship ($r^2=0.988$). IVIS demonstrated that the intravesical retention time of P407Gels was over 4 hours, which was longer than that of the FD solution (<1 hour), even though periodic urination occurred in the mice. Conclusions: FD release from P407Gels was erosion-controlled. P407Gels represent a promising system to enhance intravesical retention with extended drug delivery.