• Journal of the Korean Chemical Society
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• v.43 no.2
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• pp.182-192
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• 1999

The new GD/ICP-AES quick change over system has been developed and characterized. Within less than 15 minutes, ICP-AES could be switched to GD-AES and vise a versa. As a result, both solid and liquid samples could be analyzed in a very short period of time by the ICP/GD-AES quick change over system developed in our laboratory. The influences of the experimental variables, such as flow rate of coolant gas, flow rate of auxiliary gas, flow rate of sample carrier gas, sampling depth, orifice size of sampling cone, and rf (radio frequency) power on emission intensity have been presented. The detection limits of Cd(I) 228.8 nm, Mn (II) 257.61 nm, and Fe(II) 259.95 nm were found to be 3.86, 1.49, and 5.79 ppb, respectively. And linealities of the calibration curves were measured to be unity.

• Fire Science and Engineering
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• v.29 no.3
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• pp.31-36
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• 2015

This study analyzed the flame characteristics when igniting 200 ml of flammable liquids containing equal parts gasoline and another flammable liquid. These mixtures were used to fill a divided space in a simulation. The length of one side of the divided space was 2,000 mm, and the length of the combustion device was 1,000 mm. The mixture with alcohol had the highest flame propagation speed (0.7 s), while the mixture with light oil showed the lowest (1.2 s). The gasoline and acetone mixture reached peak flame in 25.5 s, at the highest speed, while the mixture with light oil reached peak flame in 163.7 s at the lowest speed. The gasoline and light oil showed the longest continuous combustion time (332.7 s), while the gasoline and paint thinner showed the shortest (121.5 s). A fire inspector who is examining the scene of a fire needs to analyze both the statements of the first eyewitness and the flame characteristics collectively.

• Korean Journal of Plant Tissue Culture
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• v.25 no.1
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• pp.37-43
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• 1998

The highest transformation frequency was observed when cotyledonary and hypocotyl explants of flowering cabbage (Brassica oleracea var. acephala DC) 'Eunbae' were cultured on shoot induction medium without kanamycin for 1 day, then cocultured with Agrobacterium tumefaciens LBA4404;;pGA1036 harboring tomato inhibitor II promoter and $\beta$-glucuronidae (GUS) fusion gene for 3 days. These explants were transferred to MS medium containing 20 mg/L kanamycin, 500 mg/L carbenicillin, and 1 mg/L BA. The explants were subsequently subcultured every 2 weeks. Incorporation of the GUS gene into flowering cabbage was confirmed by PCR analysis of DNA. Southern blot analysis showed that ECL-labeled GUS gene was hybridized to the expected amplified genomic DNA fragment of about 366 bp from transgenic flowering cabbage. Histochemical analysis based on the enzymatic activity of the GUS protein indicated that PI-II promoter activity was sysmatically associated with vascular tissue in wonded as well as in non-wounded leaves, petioles and stems, but not in roots. Partial wounding with razor blade showed not systemic induction but partial induction.

• Journal of ILASS-Korea
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• v.6 no.1
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• pp.18-24
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• 2001

Liquid fossil fuel contaminated by water can cause trouble in the combustion processes and affect the endurance of a combustion system. Using an optical sensor to monitor the water content instantaneously in a fuel pipeline is an effective means of controlling the fuel quality in a combustion system. In two component liquid flows of oil and water, the flow pattern and characteristics of water droplets are changed with various flow conditions. Additionally, the light scattering of the optical sensor measuring the water content is also dependent on the flow patterns and droplet characteristics. Therefore, it is important to investigate the detailed behavior of water droplets in the pipeline of the fuel transportation system. In this study, the flow patterns and characteristics of water droplets in the turbulent pipe flow of two component liquids of gasoline and water were investigated using optical measurements. The dispersion of water droplets in the gasoline flow was visualized, and the size and velocity distributions of water droplets were simultaneously measured by the phase Doppler technique. The Reynolds number of the gasoline pipe flow varied in the range of $4{\times}10^{4}\;to\;1{\times}10^{3}$, and the water content varied in the range of 50 ppm to 300 ppm. The water droplets were spherical and dispersed homogeneously in all variables of this experiment. The velocity of water droplets was not dependent on the droplet size and the mean velocity of droplets was equal to that of the gasoline flow. The mean diameter of water droplets decreased and the number density increased with the Reynolds number of the gasoline flow.

• Journal of Yeungnam Medical Science
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• v.1 no.1
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• pp.179-183
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• 1984

In recent years, an increasing number of drugs have been reported to cause direct esophageal damage. More than 30 cases on tetracyclines induced esophageal ulcer have been reported since the first description of tetracycline induced esophageal ulcer by Bokey and Hugh in 1975. In Korea, only one case of doxycycline-induced esophageal ulcer has been reported. Authors have experienced 3 cases of esophageal ulcer probably caused by tetracyclines. The patients had taken their capsules just before going to bed with little fluid intake. About 6-8 hours later they had felt substernal burning sensation and epigastric discomfort. Gastrofiberscopy revealed relatively well demarcated circular ulcers on the mid esophagus. An esophagogram showed no apparent abnormality. Patients's symptomas became negligible with antacid treatment within 2-5 days. One of the causes of the esophageal ulcer is thought to be the delay in transit time of drugs and direct esophageal damage from mucosal contact when tablets are ingested in the recumbent position without an accompanying proper quantity of fluid. If only physicians endow patients with more concern about drug induced esophageal ulcer, they could find out more increasing number of drug induced esophageal ulcers by gastroscopic examination and thereby could prevent tetracycline induced esophageal ulcer.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.232-232
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• 2011

DAF는 기존 침전 공정에 비해 뛰어난 정수 품질과 빠른 처리 시간으로 차세대 정수 공정으로 각광 받고 있다. DAF는 기포 생성 방법에 따라 용존 공기 부상법, 분산 공기 부상법, 진공 부상법, 전해 부상법, 미생물학적 부상법 등이 있다. 이 중 가장 많이 쓰이는 방식은 용존 공기 부상법으로, 과포화 상태의 기체와 액체의 혼합액을 압력을 급격히 감소시켜 기포를 발생 시키는 방법이다. 이 방법은 기포의 발생은 많지만 장비의 크기가 거대하고 시설제조 비용이 많이 드는 단점이 있다. 수중에서 발생되는 플라즈마는 그 구조와 메카니즘에 따라 생성되는 버블의 양을 제어할 수 있음을 확인하였다. 모세관 형태의 전극을 이용한 수중 방전은 전원 공급 장치만 있다면 적은 공간으로도 효과적으로 기포를 생성 할 수 있기 때문에, 수중 방전을 이용하여 기포 발생 후 DAF에 적용 가능한지 알아보고자 한다. DAF공정에서 필요한 요인으로는 기포의 크기, 개수, 성분 물질 등이 있는데, 그 중 가장 핵심은 기포의 크기 이다. 그래서 간단한 전원 장치와 리액터 제작 후 방전에 최적화 된 전극으로 기포를 발생시켜 기포의 크기를 측정하였다. 기포의 크기는 전극의 직경과 방전공간의 비율에 따라 제어가 가능함을 확인하였고 평균 기포의 크기는 약 50 ${\mu}m$로서, DAF에 적용 할 수 있는 크기이다. 일반적으로 기포의 사이즈가 작을수록 입자 제거율이 높은데, 실제 DAF공정에서 사용되는 기포의 사이즈는 80 ${\mu}m$정도 이다. 따라서 개발된 기포 발생장치를 DAF 공정에 응용한다면 높은 효율을 가질 것으로 판단된다.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.83-89
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• 2003

A temperature- and pressure-reducing process is utilized to handle the spent fuel assembly in the post-irradiation examination facility. This process includes three separated unit processes. First one is the decontamination process to clean the spent fuel assembly casks. The second process is the temperature-reducing process to reduce the temperature elevated by decay process in the spent fuel assembly. The third process is the filtration process to remove insoluble particles existed in the casks using filters. Up-to-date technologies as well as practical theories related to the temperature- and pressure-reducing process is reviewed in this report. The test-operation process for various tests and the test results of the temperature- and pressure-reducing process for J-44 and K-23 spent fuel assemblies are also described in detail. This report must be effectively used for the normal operation of the facility with the awareness of unprecedented problems which could occur by continuing operation of the PIE facility.

• Solar Energy
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• v.10 no.2
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• pp.18-27
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• 1990

The hot water producer by the combination of the solar thermal energy and freon gas compression heat has been developed. Freon R-12 gas was circulated through the system including the solar absorption panel, which has no glassing and no insulation, and the frozen and burst problems were intrinsically eliminated. The manufacturing and running costs may go further down than the regular solar hot water systems.

• The KSFM Journal of Fluid Machinery
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• v.18 no.6
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• pp.57-62
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• 2015

The test of comparing liquid flow calibration system (approved by KOLAS) for accuracy and structure change test was performed in the test bed in order to evaluate the typical characteristics of the electromagnetic flow meters and parshall flume that are generally used in the water discharging facilities. The results of the accuracy comparing test with liquid flow calibration system showed the error of less than 2%. Pharshall plume got error up to -8.3% (low flow) from the flow rate test, but less than 4% from the accumulated flow test because of offset error at high flow rate and low flow rate. Evaluation of structual change test was tested with only parshall flume using structure and it consisted of installation angle (parshall flume and level sensor) and position change. Installation angle, water level sensor angle and position changing test for parshall flume had errors of 3.1%~-9.2%, 0.4%~-5.6% and 0.2%~1.3% respectively. Especially, the error showed the largest increase when the water level sensor measured the point of decreased flow by the structure change. Therefore, error factors (change of straight pipe length, installation of obstacle or effect of foreign substances on water level sensor) that can often occur in the field should be derived and the research for optimized installation method should be carried out continuously.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.773-776
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• 2008

Restraining cracks on concrete structures can be the basic condition to improve the durability, so in this research, the resistibility on the drying shrinkage of concrete structures in the long period was being confirmed and as the reason of this shrinkage, the density of minute textures was being analyzed using a wooden prototype of a full scale produced with ready-mixed concrete and agents of glycol which can be used as a surfactant. As result of those tests, PFB technology can reduce the drying shrinkage by approximately $-100{\sim}200{\times}10^{-6}$ on a wooden prototype of a full scale and can also reduce the pore volume as the obstruction to the movement of gas or liquid by approximately $2.4{\sim}3.5$% so that PFB technology can be used to assure the resistibility on the drying shrinkage.