• Journal of Life Science
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• v.23 no.11
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• pp.1342-1350
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• 2013

We examined the effect of hydrogen sulfide ($H_2S$) in chemical hypoxia-induced injury in mouse hepatocytes. Cell viability was significantly decreased by cobalt chloride ($CoCl_2$), a well-known hypoxia mimetic agent in a time- and dose- dependent manner. Sodium hydrosulfide (NaHS, a donor of $H_2S$) pretreatment before exposure to $CoCl_2$ significantly attenuated the $CoCl_2$-induced decrease of cell viability. $CoCl_2$ treatment resulted in an increase of intracellular ROS generation, which is inhibited by NaHS or N-acetyl-cysteine (NAC, a ROS scavenger), and p38 MAPK phosphorylation, which is also blocked by NaHS or NAC. The $CoCl_2$-induced increase of the Bax/Bcl-2 ratio was attenuated by NaHS, NAC, and SB 203580 (p38 MAPK inhibitor). The $CoCl_2$-induced decrease of cell viability was also attenuated by NaHS, NAC, and SB 203580 pretreatment. Additionally, NaHS inhibited the $CoCl_2$-induced COX-2. Similar to the effect of NaHS, NAC blocked $CoCl_2$-induced COX-2 expression. Furthermore, NS-398 (a selective COX-2 inhibitor) attenuated not only the $CoCl_2$-induced increase of the Bax/Bcl-2 ratio, it also decreased cell viability. Taken together, $H_2S$ protects primary cultured mouse hepatocytes against $CoCl_2$-induced cell injury through inhibition of the ROS-activated p38 MAPK cascade and the COX-2 pathway.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.777-778
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• 2009

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.5
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• pp.659-666
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• 2010

Lysobacter antibioticus HS124 was isolated from rhizosphere soil in previous experiments, which produced lytic enzymes such as chitinase, gelatinase, lipase and protease. In addition, HS124 released an antibiotic compound, 4-hydroxyphenylacetic acid (4-HPAA). When larvae of P. xylostella was treated with HS124 culture broth, its body was destroyed, and degraded with the increase of incubation time, yielding glycine which was detected from HS124 culture broth. When 4-HPAA produced from HS124 was sprayed, larvae mortality increased with increasing concentration of 4-HPAA. When HS124 culture supplemented with Tween 80 was sprayed, its insecticidal activity against larvae was approximately 1.4 times higher compared to the culture without Tween 80. Insecticide (IS), HS124 culture broth (HS124), Magic-pi (MP) and HS124 culture broth+Magic-pi (HS124+MP) were each treated against larvae of P. xylostella to investigate their insecticidal effect where sterile diluted water (SDW) was used as a control. The highest mortality of larvae was found in HS124+MP, followed by IS, MP, HS124 and SDW respectively. Mortality of larvae in HS124 was 31% higher than that in SDW, but 41% lower than that in HS124+MP, meaning that both enzymes and antibiotics produced from HS124 may synergistically act as active agents with plant extract containing neem oil and turmeric in HS124+MP treatment. These results suggested that L. antibioticus HS124 together with plant extract can be one of candidates for biocontrol agents against Plutella xylostella.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.627-627
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• 2013

Recently, most studies concerning inorganic CdSe/ZnS quantum dot (QD)-polymer hybrid LEDs have been concentrated on the structure with multiple layers [1,2]. The QD LEDs used almost CdSe materials for color reproduction such as blue, green and red from the light source until current. However, since Cd is one of six substances banned by the Restriction on Hazardous Substances (RoHS) directive and classified into a hazardous substance for utilization and commercialization as well as for use in life, it was reported that the use of CdSe is not suitable to fabricate a photoelectronic device. In this work, we demonstrate a novel, simple and facile technique for the synthesis of ZnO-graphene quasi-core.shell quantum dots utilizing graphene nanodot in order to overcome Cd material including RoHS materials. Also, We investigate the optical and structural properties of the quantum dots using a number of techniques. In result, At the applied bias 10 V, the device produced bluish-white color of the maximum brightness 1118 cd/$m^2$ with CIE coordinates (0.31, 0.26) at the bias 10 V.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.553-555
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• 2008

현재 사용하고 있는 LCD(Liquid Crystal Display) Backlight용 램프는 주로 CCFL(Cold Cathod Fluorescent Lamp)과 EEFL(External Electrode Fluorescent Lamp)이 사용되고 있다. 하지만 이 램프는 수은을 사용하여 RoHS(the Restriction of the use of certain Hazardous Substances in electrical and electronic equipment)규제가 점점 강화되면서 사용이 제한되고 있으며, 이에 따라 수은을 사용하지 않는 램프의 제작이 불가피해지고 있다. 또한 LCD TV는 CRT와 PDP와는 다른 LCD만의 Hold-type 특성과 LC(Liquid Crystal)의 응답속도로 인하여 Motion Blur현상이 나타나는 단점이 있다. 본 논문에서는 RoHS 규제를 만족시키는 무수은 면광원 램프를 구동하기 위한 인버터를 제안한다. 제안한 인버터는 포워드 방식을 사용하여 반도체 소자 및 자기 소자의 수를 줄여서 구동회로가 간단하다. 또한 면광원 램프를 세로방향으로 6블록으로 나누어 스캔구동을 하여 Motion Blur현상을 저감 시켰다. 끝으로 실험을 통하여 제안한 인버터의 유용성을 입증하였다.

• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3350-3356
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• 2013

Quasi-classical trajectory calculations have been carried out for the reaction H+HS by using the newest triplet 3A" potential energy surface (PES). The effects of the collision energy and reagent initial rotational excitation are studied. The cross sections and thermal rate constants for the title reaction are calculated. The results indicate that the integral cross sections (ICSs) are sensitive to the collision energy and almost independent to the initial rotational states. The ro-vibrational distributions for the product $H_2$ at different collision energies are presented. The investigations on the vector correlations are also performed. It is found that the collision energies play a postive role on the forward scatter of the product molecules. There is a negative influence on both the alignment and orientation of the product angular momentum for low collision energy at low energy region. Whereas the influence of collision energy is not obvious at high energy region.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.142-145
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• 2019

In recent years, the global GEF(Green Energy Family) activities to preserve the global environment due to energy consumption have been implemented under the Kyoto Protocol for the Prohibition of Carbon Dioxide Emissions, RoHS (Restriction of Hazardous Substances directive), and WEEE(Waste Electrical and Electronice Equipment) are required to collect waste for the purpose of minimizing waste by integrating lighting and communication. In this paper, we constructed a controller that can control the illumination of RGB LED module by using fuzzy inference system and checking environmental factors(Illumination, distance to the subject, etc.) using microprocessor in real time.

• Clean Technology
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• v.16 no.3
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• pp.155-161
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• 2010

Product-based environmental regulations, such as RoHS, REACH, EuP, etc., on electrical and electronic equipments, chemicals, and so on, initiated by the European Union, are becoming a global trend. These regulations can create barriers to trade among nations worldwide and may thereby have a direct impact on the function of internal market. If domestic companies utilize well the international environmental regulations in advance, they will get good opportunity for expanding overseas market. In this paper the current status of countermeasure for overcoming the international environmental regulations in domestic industries was investigated and the future plans were discussed.

• Analytical Science and Technology
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• v.23 no.1
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• pp.1-14
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• 2010

It is of importance that all countries in worldwide, including EU and China, have adopted the Restrictions on the use of certain Hazardous Substances (RoHS) for all electronics. IEC62321 document, which was published by the International Electronics Committee (IEC) can have conflicts with the standards in the market. On the contrary Publicly Accessible Specification (PAS) for sampling published by IEC TC111 can be adopted for complementary application. In this work, we tried to find a route to disassemble and disjoint cellular phone sample, based on PAS and compare the screening methods available in the market. For this work, the cellular phone produced in 2001, before the regulation was born, was chosen for better detection. Although X-ray Fluorescence (XRF) showed excellent performance for screening, fast and easy handling, it can give information on the surface, not the bulk, and have some limitations due to significant matrix interference and lack of variety of standards for quantification. It means that screening with XRF sometimes requires supplementary tool. There are several techniques available in the market of analytical instruments. Laser ablation (LA) ICP-MS, energy dispersive (ED) XRF and scanning electron microscope (SEM)-energy dispersive X-ray (EDX) were demonstrated for screening a cellular phone. For quantitative determination, graphite furnace atomic absorption spectrometry (GF-AAS) was employed. Experimental results for Pb in a battery showed large difference in analytical results in between XRF and GF-AAS, i.e., 0.92% and 5.67%, respectively. In addition, the standard deviation of XRF was extremely large in the range of 23-168%, compared with that in the range of 1.9-92.3% for LA-ICP-MS. In conclusion, GF-AAS was required for quantitative analysis although EDX was used for screening. In this work, it was proved that LA-ICP-MS can be used as a screening method for fast analysis to determine hazardous elements in electrical products.

• 전자공학회논문지 IE
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• v.47 no.3
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• pp.7-13
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• 2010

In this paper, an efficient contrast enhancement algorithm using weighted histogram modification is proposed. For contrast enhancement, histogram equalization (HE) and histogram stretching (HS) are effective techniques. However, HE and HS may have excessive contrast enhancement. Proposed method using weighted histogram modification produces better natural and enhanced results than those of conventional contrast enhancement methods without artifacts.