• YAKHAK HOEJI
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• v.32 no.4
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• pp.287-293
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• 1988

Oxygen free radical have recently been found to mediate cell injury after ischemia in the kidney. The purpose of our study was to determine whether selenium had an effect on damge mediated by oxygen free radical in inorganic mercury induced renal failure, toxic model of renal failure. Toxic renal failure model was produced by subcutaneous injection of mercuric chloride (4mg/kg) once a day for 7 consecutive days. In additionally, coadministration of sodium selenite (1mg/kg) was performed by the same condition. As a consequence of this study, we were able to detect partially unequivocal role of selenium as below dipicted. The combination of sodium selenite showed that markedly inhibited production of superoxide radical in mercuric chloride alone. On the other hand, combined sodium selenite was unable to enhance against significantly lowered superoxide dismutase activity after mercuric chloride insult. However, simultaneous administration of sodium selenite was inclined to induce mitochondrial superoxide dismutase and catalase.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.1
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• pp.20-26
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• 2002

HID(high intensity discharge)lamps include high pressure mercury lamp, high pressure sodium lamp and metal halide lamp. Metal halide lamps have been considered to be one of the most erective light sources. These lamps have good efficiency, good color rendering and good focusing capability. The objective of this research is to alum on the metal halide lamp(MH70W) by the developed electronic ballast with free voltage input(AC 100∼277V). The developed electronic ballast consists of a free voltage input converter, a flyback converter ＆ half-bridge inverter, ignitor ＆ protector and control1er. Experimental results show that developed electronic ballast turns on the metal halide lamp(MH70W) with free voltage input(AC 100∼277V) very well.

• Journal of Ginseng Research
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• v.32 no.2
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• pp.150-154
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• 2008

Twenty five albino rats were divided into five groups for conducting this experiment. The first group was for positive control (Vitamin C, ascorbic acid), the second group was of Panax ginseng (10 mg/kg body weight) treated group after bio-activity assay, the third group was of mercuric chloride treated group (0.033 mg/kg body weight) based on calculating $LD_{50}$ 9.26 mg/kg body weight by probit analysis, the fourth group was of mercuric chloride (0.033 mg/kg body weight) followed by Panax ginseng (10 mg/kg body weight) and the fifth group was Panax ginseng (10 mg/kg body weight) followed by mercuric chloride (0.033 mg/kg body weight) treated group. The interval between intake of Panax ginseng and mercuric chloride was of 2 hours in groups, fourth and fifth respectively. Comparative free radical scavenging property of Panax ginseng was studied under three in vitro models (role model for calculating scavenging activity) viz. DPPH method (hydroxyl free radicals), Nitric oxide method (nitrile free radicals) and Lipid peroxidation (mercury free radicals).

• Journal of Korean Society of Water and Wastewater
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• v.35 no.6
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• pp.489-496
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• 2021

Water disinfection using UV-LED(Light emitting diode) has many advantages, such as smaller footprint and power consumption as well as relatively longer lifespan than those of conventional mercury-UV lamps. Moreover, UV-LED disinfection is considered an environmentally benign process due to its mercury-free nature. In this study, disinfection using an LED module emitting 275nm UV was carried out. 384 UV-LEDs were put into a cylinder tube with a capacity of 1.7 liters. The UV intensity of the UV-LED module was controlled from 1.7 to 8.4 mW/cm². The disinfection efficiency for the model microorganism solutions(E. coli ) was monitored. As the UV intensity(I) and contact time(t) varied, inactivation of the microorganisms from 2 to 4-log-removals(i.e., 99 to 99.99% of disinfection efficiency) was achieved. Disinfection using UV-LED was followed to 1^st order reaction and the reaction rate constant, k was determined. In addition, the relationship between UV intensity(I) and contact time(t) in order to obtain 99.99% of disinfection efficiency was modeled: I^1.2·t= 460, which indicates that the product of UV intensity and contact time requiring 4-log-removals is always constant.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.4
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• pp.725-729
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• 2003

In this paper, a mercury-free flat discharge lamp with opposite electrode structure, a couple of phosphor layer and discharge vessel has been studied for LCD back-lighting. When the drive voltage conditions were set properly, a uniform discharge generates over entires emitting surface. The firing voltage was increased with increasing the discharge gas pressure. It was considered that this tendency was resulted from the decrease of mean free paths due to the increase of discharge gas pressure. The maximum luminance of 2700[cd/m2] was obtained in the green emitting FFL.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.624-627
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• 2004

본 논문은 LCD Backlight로 사용되고 있는 CCFL의 문제점을 해결하기 위해 간단한 구조를 가지는 mercury-free, Xe 평판형 형광램프에 대한 연구를 하였다. 일반적으로, 수은을 포함한 형광램프는 낮은 온도에서의 휘도문제와 상대적으로 긴 점등시간, 수명과 특히, 환경 문제가 있다. 본 논문에는 화학적으로 안정한 불활성 가스인 Xe을 사용함으로써 기존의 백라이트가 가지고 있는 문제점을 해결하였다. 제작된 8인치$(200{\times}156{\times}10mm)$ 램프는 AC 펄스 전압에 의해 높은 균일도, 안정한 방전, 우수한 전기적 및 광학적 특성을 가진다. 또한 본 연구에서, 무수은 Xe 평판형 형광램프의 전극폭에 대한 전기적 및 광학적 실험을 통하여 90[%]의 균일도에서 $7,000[cd/m^2]$의 휘도와 30[lm/W]의 효율을 얻었다.

• Journal of Applied Reliability
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• v.5 no.2
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• pp.241-259
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• 2005

The environmental problem is a main subject of the 21C and an environment destruction phenomenon by various kinds of environmental materials is reaching serious level. Nations to be classified as the environmental developed country, are born again environmental rich country. And they earn a large income by trade Every kind environmental resource in an international commercial transaction. Especially, the study that a reliability assessment method to prevent to reliability problem to be happened when the solder lead(lead-free solder), non-cd component, non-bromide component(without the polybrominated biphenyls(PBB) and polybrominated diphenyl ethers(PBDE))and hexavalent chromium(Cr VI) clearance component and mercury-free applied to electronic equipment is progressed. As the result of the study for applying of a reliability assessment technique of lead-free solder that recognized the most of urgent problem at the company, combination accelerated life test could taken by adding and appling the part of a humidity acceleration part to Eyring Model which is proposed by R.E.Thomas. The reliability assessment methods study of PWB clean environmental materials is expected to respond to a reliability elevation and environmental material regulation policy spreading all over the world by beginning form Europe.

• Korean Journal of Plant Resources
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• v.30 no.6
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• pp.670-678
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• 2017

Persimmon seeds contain considerable amounts of minerals, amino and organic acids, natural antioxidants and phenolic compounds. The objective of this study was to investigate quality characteristics and antioxidant potential of Korean persimmon seeds. The pH (4.88-4.94), color values, contents of minerals, free amino acids, organic acids, and phenolic compounds and DPPH free radical scavenging potentials of persimmon seed extracts significantly (p < 0.05) varied with the genotypes. This study showed that the seeds could be used as a source of different mineral elements (47.14-85.07 mg/kg) without any measureable amount of heavy metals such as arsenic, cadmium, lead and mercury. Similarly, considerable amounts of organic (1550.13-2413.08 mg/kg) and essential amino (50.85-54.03 mg/kg) acids and total phenolic compounds ($1227.91-1307.78{\mu}g$ gallic acid equivalent/g) were also found in the seed extracts, indicating their potential food value as a natural antioxidant. Results of the present study imply that prethanol-A, a food preservative, can be used as an effective extraction to obtain the minerals, organic and free amino acids, and phenolic compounds from the persimmon seeds, which possess a big potential to be commercially used in food, cosmetic and pharmaceutical industries.

• Proceedings of the Korean Reliability Society Conference
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• 2005.06a
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• pp.393-404
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• 2005

The environmental problem is a main subject of the 21C and an environment destruction phenomenon by various kinds of environmental materials is reaching serious level. Nations to be classified as the environmental developed country, are born again environmental rich country. And they earn a large income by trade Every kind environmental resource in an international commercial transaction. Especially, the study that a reliability assessment method to prevent to reliability problem to be happened when the solder lead(lead-free solder), non-cd component, non-bromide component(without the polybrominated biphenyls(PBB) and polybrominated diphenyl ethers(PBDE))and hexavalent chromium(Cr VI) clearance component and mercury-free applied to electronic equipment is progressed. As the result of the study for applying of a reliability assessment technique of lead-free solder that recognized the most of urgent problem at the company, combination accelerated life test could taken by adding and appling the part of a humidity acceleration part to Eyring Model which is proposed by R.E.Thomas. The reliability assessment methods study of PWB clean environmental materials is expected to respond to a reliability elevation and environmental material regulation policy spreading all over the world by beginning form Europe.

• Geomechanics and Engineering
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• v.30 no.5
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• pp.471-478
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• 2022

Creep of soils has a significant impact on mechanical properties. The one-dimensional consolidation creep test, thermal analysis test, scanning electron microscope (SEM) test, and mercury compression test were performed on Guilin red clay to study the changes in bound water and microstructure during the creep process of Guilin red clay. According to the results of the tests, only free and weakly bound water is discharged during the creep of Guilin red clay. When the consolidation pressure p is in the 12.5-400.0 kPa range, it is primarily the discharge of free water; when the consolidation pressure p is in the 800.0-1600.0 kPa range, the weakly bound water is converted to free water and discharged. After consolidation creep, the microstructure of soil changes from granular overhead contact structure to flat sheet-like stacking structure, with a decrease in the number of large and medium pores, an increase in the number of small and micro pores, and a decrease in the fractal dimension of pores. The creep process of red clay is the discharge of weakly bound water as well as the compression of large pores into small pores and the transition of soil particles from loose to dense.