• 한국기계가공학회지
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• 제19권11호
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• pp.58-63
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• 2020

The fuel injection amount and timing along with the ignition timing for the gasoline engine of a racing car were adjusted using an electronic control unit (ECU), and the engine performance was evaluated through an acceleration test. The fuel map for the fuel injection amount and ignition map for the ignition timing were derived. Using the transient throttle control, the air-fuel ratio could be maintained at a constant value even in the case of a sudden throttle operation. In the flat shift, ignition blocking was more effective than fuel blocking. In a 75 m acceleration test, the required duration without and with ECU control was 4.47 s and 3.99 s, respectively. Notably, the acceleration could be improved by approximately 10.7% when the ECU control was implemented.

• 마이크로전자및패키징학회지
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• 제28권4호
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• pp.51-55
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• 2021

본 논문은 보통 병원에서 간호사가 수작업으로 진행하는 약물주입 과정을 대신할 수 있는 의료용 미세 유량 제어 장치를 소개한다. 이는 아두이노로 구현되었으며 환자의 지속적인 관리에 도움이 되고자 한다. 기본적으로 연동펌프를 통해 약물이 주입되며 RGB color sensor를 통해 배출액의 색상을 값으로 받아들이고 이 값을 바탕으로 수액백에 달린 연동펌프의 모터 속도를 조절하는 알고리즘을 아두이노 코딩을 통해 구현한다. 전체적인 시스템은 배터리를 통해 작동되며 연구실에서 355nm UV pulsed laser를 통해 제작한 LIG strain sensor의 추가를 통해 수액백으로부터 주입되는 약물의 양을 측정한다. 이렇게 제작된 미세 유량 제어 장치는 모든 과정을 수작업으로 진행해오던 병원에 곧장 사용 가능하며 간호사의 편의를 제공하고자 한다. 이 장치를 통해 한층 향상된 의료서비스를 제공할 수 있다.

• Nuclear Engineering and Technology
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• 제49권1호
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• pp.54-70
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• 2017

The accumulator is a passive safety injection device for emergency core cooling systems. As an important safety feature for providing a high-speed injection flow to the core by compressed nitrogen gas pressure during a loss-of-coolant accident (LOCA), the accumulator injects its precharged nitrogen into the system after its coolant has been emptied. Attention has been drawn to the possible negative effects caused by such a nitrogen injection in passive safety nuclear power plants. Although some experimental work on the nitrogen injection has been done, there have been no comparative tests in which the effects on the system responses and the core safety have been clearly assessed. In this study, a new thermal hydraulic integral test facility-the advanced core-cooling mechanism experiment (ACME)-was designed and constructed to support the CAP1400 safety review. The ACME test facility was used to study the nitrogen injection effects on the system responses to the small break loss-of-coolant accident LOCA (SBLOCA) transient. Two comparison test groups-a 2-inch cold leg break and a double-ended direct-vessel-injection (DEDVI) line break-were conducted. Each group consists of a nitrogen injection test and a nitrogen isolation comparison test with the same break conditions. To assess the nitrogen injection effects, the experimental data that are representative of the system responses and the core safety were compared and analyzed. The results of the comparison show that the effects of nitrogen injection on system responses and core safety are significantly different between the 2-inch and DEDVI breaks. The mechanisms of the different effects on the transient were also investigated. The amount of nitrogen injected, along with its heat absorption, was likewise evaluated in order to assess its effect on the system depressurization process. The results of the comparison and analyses in this study are important for recognizing and understanding the potential negative effects on the passive core cooling performance caused by nitrogen injection during the SBLOCA transient.

• Korean Journal of Radiology
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• 제2권1호
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• pp.28-36
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• 2001

Objective: To provide a systematic overview of the effects of various parameters on contrast enhancement within the same population, an animal experiment as well as a computer-aided simulation study was performed. Materials and Methods: In an animal experiment, single-level dynamic CT through the liver was performed at 5-second intervals just after the injection of contrast medium for 3 minutes. Combinations of three different amounts (1, 2, 3 mL/kg), concentrations (150, 200, 300 mgI/mL), and injection rates (0.5, 1, 2 mL/sec) were used. The CT number of the aorta (A), portal vein (P) and liver (L) was measured in each image, and time-attenuation curves for A, P and L were thus obtained. The degree of maximum enhancement (Imax) and time to reach peak enhancement (Tmax) of A, P and L were determined, and times to equilibrium (Teq) were analyzed. In the computed-aided simulation model, a program based on the amount, flow, and diffusion coefficient of body fluid in various compartments of the human body was designed. The input variables were the concentrations, volumes and injection rates of the contrast media used. The program generated the time-attenuation curves of A, P and L, as well as liver-to-hepatocellular carcinoma (HCC) contrast curves. On each curve, we calculated and plotted the optimal temporal window (time period above the lower threshold, which in this experiment was 10 Hounsfield units), the total area under the curve above the lower threshold, and the area within the optimal range. Results: A. Animal Experiment: At a given concentration and injection rate, an increased volume of contrast medium led to increases in Imax A, P and L. In addition, Tmax A, P, L and Teq were prolonged in parallel with increases in injection time The time-attenuation curve shifted upward and to the right. For a given volume and injection rate, an increased concentration of contrast medium increased the degree of aortic, portal and hepatic enhancement, though Tmax A, P and L remained the same. The time-attenuation curve shifted upward. For a given volume and concentration of contrast medium, changes in the injection rate had a prominent effect on aortic enhancement, and that of the portal vein and hepatic parenchyma also showed some increase, though the effect was less prominent. A increased in the rate of contrast injection led to shifting of the time enhancement curve to the left and upward. B. Computer Simulation: At a faster injection rate, there was minimal change in the degree of hepatic attenuation, though the duration of the optimal temporal window decreased. The area between 10 and 30 HU was greatest when contrast media was delivered at a rate of 2 3 mL/sec. Although the total area under the curve increased in proportion to the injection rate, most of this increase was above the upper threshould and thus the temporal window was narrow and the optimal area decreased. Conclusion: Increases in volume, concentration and injection rate all resulted in improved arterial enhancement. If cost was disregarded, increasing the injection volume was the most reliable way of obtaining good quality enhancement. The optimal way of delivering a given amount of contrast medium can be calculated using a computer-based mathematical model.

• 한국해양환경ㆍ에너지학회지
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• 제18권2호
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• pp.94-101
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• 2015

$CO_2$ 배출을 줄이기 위해서 최근 $CO_2$ 포집 및 저장 기술에 관한 연구가 전세계적으로 활발히 진행되고 있다. 국내에서는 해양퇴적층을 대상으로 한 $CO_2$ 저장 연구가 활발히 진행되고 있다. 이러한 $CO_2$ 저장 연구에서 가장 중요한 요소 중 하나는 안전성 확보이다. 지중저장의 안전성 확보를 위해서 저장 $CO_2$의 누출 가능성과 누출 특성을 예측하는 것은 매우 중요하다. 본 연구에서는 해양지중에 저장된 $CO_2$가 단층을 통하여 누출될 수 있는 시나리오를 가정한 후, 지중공간 내 $CO_2$ 확산 및 누출 거동을 TOUGH2-MP ECO2N을 사용하여 시뮬레이션 하였다. 대상 저장지는 150 m 수심의 대륙붕 해저 825 m 지점에 있는 두께 150 m의 대염수층이고, 누출이 진행되는 경로는 주입정에서 1,000 m 떨어진 단층이다. 저장된 $CO_2$는 주입 압력과 밀도차에 의한 부력에 의해서 이동하게 된다. $CO_2$가 해수면으로 누출되기 위해서는 주입정에서 인가된 압력차가 $CO_2$를 단층 하단에 도달할 수 있게 할 만큼 충분히 커야 한다. 단층 하단에 도달한 $CO_2$는 추가적인 압력 구배가 없어도 부력에 의해서 누출된다. $CO_2$ 주입과 동시에 공극수는 $CO_2$가 누출되기 전까지 지속적으로 해저면으로 누출된다. $CO_2$가 해저면에 도착하면 공극수의 누출은 중단되고, 누출되는 $CO_2$질량에 상응하는 해수가 부력의 반대 작용으로 인해 단층으로 유입되는 것으로 계산되었다. 주입량이 누출에 미치는 영향을 평가하기 위하여 연간 $CO_2$ 주입량 100만 톤, 75만 톤, 50만 톤 에 대한 민감도분석을 수행하였으며, 누출이 일어난 시점은 주입 후 각각 11.3 년, 15.6년, 23.2년으로 계산되었다. 또한, 주입이 종료 된 이후에도 누출은 특정 기간 동안 지속되는 것으로 계산되었다. 누적 주입량 대비 누적 누출량은 연간 $CO_2$ 주입량이 100만 톤, 75만 톤, 50만 톤인 경우, 각각 19.5%, 11.5%, 2.8% 이다.

• 터널과지하공간
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• 제24권6호
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• pp.418-429
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• 2014

지열에너지, 원유회수증진을 포함한 석유/가스개발, 셰일가스 개발과 이산화탄소 지하저장(CCS)의 네가지 에너지개발기술에서 시추공 유체주입 및 배출과정에서 발생하는 유발지진에 관하여 문헌조사를 통하여 사례를 분석 하였다. 기술문헌에 보고된 가장 큰 유발지진은 지하 저류층으로 큰 부피의 유체가 주입 된데 비하여 배출은 적어 평형이 취해지지 않았던 프로젝트와 관련이 있다. 자료의 통계적 분석 결과, 주입되고 배출된 유체의 순주입량의 정도가 지하의 응력조건, 공극유압 등 유발지진을 일으키는 여러 요인들을 포함하여 표현하는 단일변수 역할 을 할 수도 있다는 것을 보여주고 있다. 따라서 지열개발과 대부분의 석유, 가스개발과 같은 에너지 개발프로젝트는 총 주입량과 총 배출량의 평형을 유지하도록 설계 함으로서 유발지진이 일어날 확률을 대폭 줄일 수도 있다. 반면에 장기간에 걸쳐 많은 양을 주입하는 폐수 처리정이나 CCS 프로젝트가 보다 큰 유발지진을 일으킬 개연성이 있는 것으로 나타났다.

• 한국자동차공학회논문집
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• 제15권5호
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• pp.9-16
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• 2007

Since the liquid phase LPG injection(LPLI) system has an advantage of higher power and lower emission characteristics than the mixer type fuel supply system, many studies and applications have been conducted. However, the heat extraction, due to the evaporation of liquid fuel, causes not only a dropping of LPG fuel but also icing phenomenon that is a frost of moisture in the air around the nozzle tip. Because both lead to a difficulty in the control of accurate air fuel ratio, it can result in poor engine performance and a large amount of HC emissions. The experimental investigation was carried out on the bench test rig in this study. It was found that n-butane, that has a relatively high boiling point($-0.5^{\circ}C$), was a main species of droplet composition and also found that the droplet problem was improved by the use of a large inner to outer bore ratio nozzle whose surface roughness is smooth. The icing phenomena were decreased when the an engine head temperature was increased, although a large amount of icing deposit was still observed in the case of $87^{\circ}C$. Also, it was observed that the icing phenomenon is improved by using anti-icing bushing.

• 대한방사성의약품학회지
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• 제6권1호
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• pp.10-19
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• 2020

Boron Neutron Capture Therapy (BNCT) has the advantage of selectively removing cancer cells ingesting boron compounds. In this study, the benefits for treatment time and boron compound injection dose were compared between current neutron sources and a high current neutron sources to be developed in near future. The time-activity curve (TAC) of GBM (Glioblastoma) for one bolus injection was obtained by applying modified 3 compartment model. The treatment time was determined for an accelerator-based neutron sources at the present time and a high current accelerator based neutron source to be developed in the near future. In the case of the double amount of IAEA-recommended neutron flux, the treatment time was shortened to 15 minutes. In the case of high current accelerators, which are five times the amount of IAEA-recommended neutron flux, the irradiation time is within 5 minutes. The use of a high current accelerator based neutron source in BNCT is advantageous in terms of treatment time. In addition, it can increase the efficiency of use of neutrons and reduce the boron compound injection dose to patients, thus reducing pharmacological toxicity.

• The Korean Journal of Physiology and Pharmacology
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• 제5권5호
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• pp.367-371
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• 2001

The chromosome 7-linked long QT syndrome (LQT2) is caused by mutations in the human ether-a- go-go-related gene (HERG) that encodes the rapidly activating delayed rectifier $K^+$ current, $I_{Kr},$ in cardiac myocytes. Different types of mutations have been identified in various locations of HERG channel. One of the mechanisms for the loss of normal channel function is due to membrane trafficking of channel protein. The decreased channel function in some deletion mutants appears to be due to loss of coupling with wild type HERG to form the functional channel as the tetramer. Most of missense mutants with few exceptions could interact with wild type HERG to form functional tetramer and caused dominant negative suppression with co-injection with wild type HERG showing variable effects on current amplitude, voltage dependence, and kinetics of activation and inactivation. Two missense mutants at pore regions of HERG found in Japanese LQT2 (A614V and V630L) showed accentuated inward rectification due to a negative shift in steady-state inactivation and fast inactivation. One mutation in S4 region (R534C) produced a negative shift in current activation, indicating the S4 serving as the voltage sensor and accelerated deactivation. The C-terminus mutation, S818L, could not express the current by mutant alone and did not show dominant negative suppression with co-injection of equal amount of wild type cRNA. Co-injection of excess amount of mutant with wild type produced dominant negative suppression with a shift in voltage dependent activation. Therefore, multiple mechanisms are involved in different mutations and functional abnormality in LQT2. Further characterization with the interactions between various mutants in HERG and the regulatory subunits of the channels (MiRP1 and minK) is to be clarified.

• 한국지반공학회논문집
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• 제15권3호
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• pp.99-111
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• 1999

천공굴착을 선행하게 되는 배토형 auger-cast 말뚝의 경우, 굴착 및 지반교란에 의한 횡방향응력의 감소로 인하여 주면마찰력이 타입식 말뚝에 비해 작게 발휘되는 것이 일반적이다. 이러한 auger-cast말뚝의 주면마찰력을 향상시킬 수 있는 방법으로 팽창제의 사용과 가압주입의 적용효과를 고찰하고자 다짐 조성된 화강풍화토 지반에서의 팽창성 몰탈을 사용한 auger-cast 모형말뚝의 실내실첩을 실시하였다. 모형말뚝은 팽창제의 양과 주입방법, 그리고 토조가압의 조건들을 변화시키면서 모형토조안에 제작되었다. 실험결과 팽창제의 사용이 증가함에 따라 말뚝의 주면마찰력이 점점 증가하는 경향으로 나타났으며, 이러한 증가의 폭은 가압주입이 적용되었을 때 더 뚜렷하게 발생하였다. 일반 몰탈을 가압 없이 주입하여 시공한 말뚝의 주면마찰력과 비교하여, 가압주입 없이 팽창제만 사용된 경우, 그리고 팽창제와 가압주입이 병행되어 사용되어진 경우 각각 2%, 그리고 56%까지 주면마찰력이 증가되는 것으로 나타났다.