• Korean Chemical Engineering Research
• /
• v.55 no.3
• /
• pp.307-312
• /
• 2017

In this study, the electrochemical performance of surface modified carbon using the PFO (pyrolyzed fuel oil) was investigated by chemical activation with KOH and $K_2CO_3$. PFO was heat treated at $390{\sim}400^{\circ}C$ for 1~3h to prepared the pitch. Three carbon precursors (pitch) prepared by the thermal reaction were 3903 (at $390^{\circ}C$ for 3h), 4001(at $400^{\circ}C$ for 1h) and 4002 (at $400^{\circ}C$ for 2h). Also, the effect of chemical activation catalysts and mixing time on the development of porosity during carbonization was investigated. The prepared carbon was analyzed by BET and FE-SEM. It was shown that chemical activation with KOH could be successfully used to develop carbon with specific surface area ($3.12m^2/g$) and mean pore size (22 nm). The electrochemical characteristics of modified carbon as the anode were investigated by constant current charge/discharge, cyclic voltammetry and electrochemical impedance tests. The coin cell using pitch (4002) modified by KOH has better initial capacity (318 mAh/g) than that of other pitch coin cells. Also, this prepared carbon anode appeared a high initial efficiency of 80% and the retention rate capability of 2C/0.1 C was 92%. It is found that modified carbon anode showed improved cycling and rate capacity performance.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.1 no.3
• /
• pp.225-232
• /
• 2013

The inorganic insulating material was fabricated with quartzite, ordinary portland cement(OPC), lime, anhydrous gypsum and foaming agent by hydrothermal reaction. The inorganic insulating material was fabricated by using autoclave chamber under high-temperature and high-pressure. The inorganic insulating material is a porous lightweight concrete. Because of its porous structure, properties of inorganic insulating material were light-weight and high-heat insulation property. Properties of fabricated inorganic insulating material were $0.26g/cm^3$ in specific gravity, 0.4MPa in compressive strength and 0.064W/mK in thermal conductivity. In this study, the inorganic insulating material was fabricated and analyzed at different size of quartzite/OPC, various foaming reagent and functional additives to improve the properties. Consequently, polydimethylsiloxane can improve density and thermal conductivity. Especially, polydimethylsiloxane showed excellent improvement in compressive strength.

• Korean journal of applied entomology
• /
• v.57 no.3
• /
• pp.165-175
• /
• 2018

Insects are known to live at wide range of temperature, but can not survive when they are exposed to over $40^{\circ}C$ or below supercooling point. The larvae of Helicoverpa assulta have been reared at high ($35^{\circ}C$), low (3 to $10^{\circ}C$), and room temperature ($25^{\circ}C$; control). To identify stress-related genes, the transcriptomes of fat body have been analyzed. Genes such as cuticular proteins, fatty acyl ${\Delta}9$ desaturase and glycerol 3 phosphate dehydrogenase were up-regulated whereas chitin synthase, catalase, and UDP-glycosyltransferase were down-regulated at low temperature. Superoxide dismutase, metallothionein 2, phosphoenolpyruvate carboxykinase and trehalose transporter have been up-regulated at high temperature. In addition, expressions of heat shock protein and glutathione peroxidase were increased at high temperature, but decreased at low temperature. These temperature-specific expressed genes can be available as markers for climate change of insect pests.

• Journal of Periodontal and Implant Science
• /
• v.33 no.2
• /
• pp.277-288
• /
• 2003

It has been suggested that increased number and activity of phagocytes in periodontitis lesion results in a high degree of reactive oxygen species (ROS) such as superoxide anion, hydrogen peroxide, nitric oxide and peroxynitrite. There are few reports on the relationship between ROS and MMPs expressions in gingival fibroblast. We studied to elucidate whether and how ROS, especially nitric oxide affects the MMP expression. Human gingival fibroblasts and HTl080 cells (human fibrosarcoma sell line as reference) were grown in DMEM supplemented with 10 mM HEPES, 50 mg/L gentamicin, and 10% heat inactivated fetal bovine serum with addition of various reactive oxygen species (ROS). Culture media conditioned by cells were examined by gelatin zymography. HT1080 cells expressed proMMP-2 and proMMP-9, but human gingival fibroblasts (HGF) produced only proMMP-2. Hydrogen peroxide upregulated MMP-9 expression in HT1080 cells, whereas in human gingival fibroblast SNP treatment showed marked increase in MMP-2 level compared to other ROS. These results suggest that the effects of ROS on MMPs expressions are cell-type specific. RT-PCR for MMP-2 and TIMP-2 m-RNA were performed using total RNA from cultured cells under the influence various kinase inhibitors. In HT1080 cells, treatment with FPTI III (Ras processing inhibitor) and LY294002 (PI3-kinase inhibitor) resulted in inhibition of MMP-2 and MMP-9 expressions, suggesting that Ras/P13-kinase pathway is important for MMPs expression in HT1080 cells. In gingival fibroblasts, treatment with FPTI III and PDTC (NF-kB inhibitor) showed marked decrease in MMP-2 regardless of the of SNP , suggesting that Ras/NF-kB could be the key pathway for NO-induced MMP-2 expression in gingival fibroblasts. This study showed that ROS, especially nitric oxide, could be the critical mediator of periodontal disease progression through control of MMP-2 expression in gingival fibroblasts possibly via Ras/NF-kB pathway.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.36 no.9
• /
• pp.895-900
• /
• 2012

This paper aims to examine the effect of nanodroplets on pool-type absorption heat transfer enhancement and to find the relationship between the dispersion stability and the absorption performance. The concentrations of oil and surfactant are considered as the key parameters. $C_{12}E_4$ and Tween20 are used as the surfactants and N-decane oil is added to the $NH_3/H_2O$ solution to make the binary nanoemulsion fluids. Binary nanoemulsion fluids are dispersed by the ultrasonic vibrator and the stirrer under specific conditions. The dispersion stability of binary nanoemulsion fluids for each oil concentrations is evaluated from the droplet size and Tyndall effect analysis. The absorption performance of binary nanoemulsion fluids is compared with the result of dispersion stability. In addition, it is found that the binary nanoemulsion fluid is a strong candidate as a new working fluid for absorption applications.

• Information Systems Review
• /
• v.11 no.2
• /
• pp.147-167
• /
• 2009

As global climate changes, the interest in environmental crisis is increasing and a number of international agreements and regulations against this crisis are being established. Global information technology(IT) corporations are building their own pro-environmental green IT strategies to cope with the regulatory measures. Green IT broadly refers to pro-environmental technologies designed to replace hazardous materials, maximize energy effectivity, and find alternative energies. In the current stage of the IT industry development, Green IT specifically refers to the technologies that deal with the server heat generation and the energy reduction in data center. This study defines the concept of Green IT and reviews its origin and necessity. Then, it examines the issues regarding Green IT industry in Korea as well as other countries and compares the Green IT strategies developed in each country. Reviewing the recent development of IT and data center market enables us to see that overall Green IT strategies focus on the establishment of Green Internet Data Centers. Therefore, this study analyzes the cases in which some domestic and foreign corporations introduced Green Data Centers in order to examine the protocol and legal requirements for building Green IT, the aspects of environmental evaluation and design, and specific strategies for launching Green IT strategies and its future assignments. The conclusions of this study are as follows. First, to introduce Green Data Center as a strategy to build Green IT, the government and corporations should cooperate with each other. Partial introduction at the initial stage is desirable because, through the process, mutual trust between the two parties can be built more smoothly. Second, CEO's determination to build Green IT and continue its operation is indispensable. CEO's are required to have clear understanding as to why Green IT needs to be built and how it should be constructed. Those who initiate the construction of Green Data Center for Green IT need to know the definition and necessity of Green IT while at the same time understanding the implicit meanings of Green IT. They also need to be aware of future-oriented values of Green Data Center and readjust their corporate business activities in the pro-environmental direction. Finally, not only the CEOs' pro-environmental activities but also the change of mind on the part of all corporate employees is required to realize Green IT. It should be remembered that pro-environmental Green IT starts with minor activities.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.161-161
• /
• 2017

Seed endophytes are very remarkable groups of bacteria for their unique abilities of being vertically transmitted and conserved. As plants attain hybrid vigor and heterosis in the process of crossbreeding, this might also lead to the changes in the community structure and diversity of plant endophytes in the hybrid plants ultimately affecting the endophytes of the seeds. It would be interesting to characterize how seed endophyte composition change over time. The objective of this study is to gain insights into the influence of natural crossbreeding and parental lineage in the seed bacterial endophytic communities of two pure inbred lines exploring contributions of the two most important sources of plant endophytes - colonization from external sources and vertical transmission via seeds. Total genomic DNA was isolated from rice seeds and bacterial DNA was selectively amplified by PCR. The diversity of endophytic bacteria was studied through Terminal-Restriction Fragment Length Polymorphism (T-RFLP) analysis. Diversity between the original parents and the pure inbred line may show significant differences in terms of richness, evenness and diversity indices. Heat maps reveal astonishing contributions of both or either parents (IR29 ${\times}$ Pokkali and AT401 ${\times}$ IR31868) in the shaping of the bacterial seed endophytes of the hybrid, FL478 and IC32, respectively. Most of the T-RFs of the subsequent pure inbred line could be traced to any or both of the parents. Comparison of common and genotype-specific T-RFs of parents and their offspring reveals that majority of the T-RFs are shared suggesting higher transmission of bacterial communities common to both parents. The parents influence the bacterial community of their offspring. Unique T-RFs of the offspring also suggest external sources of colonization particularly as the seeds are cultivated in different ecogeographical locations. This study showed that host parental lines contributed greatly in the shaping of bacterial seed endophytes of their offspring. It also revealed transmission and potential conservation of core seed bacterial endophytes that generally become the dominant microbiota in the succeeding generations of plant hosts.

• Applied Chemistry for Engineering
• /
• v.24 no.3
• /
• pp.314-319
• /
• 2013

In this study, nitrogen doped $TiO_2$ ($N-TiO_2$) coated on an activated carbon pellet (ACP) was prepared using sol-gel and the solid state heat treatment of urea to improve the removal property of volatile organic compounds (VOCs). To explore the visible light photocatalytic activity of the ACP under the light emitting diods (LED), the removal property of benzene gas was characterized by gas chromatography. The SEM and BET results show that the increment of titanium tetra isopropoxide contents leads to the increased $TiO_2$ coating amount of ACP surface and decreased specific surface area. From the results of benzene gas removal, the breakthrough time of ACP10 increased about 2 times compared to that of the ACP. The improved performance was attributed to the $N-TiO_2$ coating on ACP surface, which could be more effective to remove benzene gas under the condition of LED lamp.

• Journal of Energy Engineering
• /
• v.19 no.1
• /
• pp.8-15
• /
• 2010

As environmental friendly energy system, distributed micro gasturbine is focused on new energy source for overcoming brand new construction area of power generation. This distributed micro gasturbine system has the powerful characteristics as belows; 1) environmental friendly features NOx < 9 ppm, noise < 65 db 2) various fuel flexbility which is used such as natural gas, diesel, low calory new & renewable fuel, kerosene. 3) high specific output power based on small area and is avilable for very easy and compact installation. There are many new installation sites in USA and Japan from 1998. On the other hand the exhisting large power system was constructued by the sea side, this compact power system is now installed by enduser in downtown area and supplying combined heat & power, has the various apllication on-site power generation. In recently, there is the very important issue for new & reliablbe energy development and spreading out. This paper represent as belows for important system characteristics; 1) grid connection modeling 2) system operation characteristics 3) on-site operation result and evaluation output of power quality analysis.

• The Journal of Internal Korean Medicine
• /
• v.19 no.1
• /
• pp.524-552
• /
• 1998

Purgation therapy has played an important role as a influential remedy from the begining of the Chinese medicine. Especially purgation therapy is raised as the effective remedy on the acute infectious disease in the book of 'Treatise on Febrile Disease'. But It was inclined to cold-nature and available only in the excess syndrome. Nevertheless it is evident that the book has showed an example of this therapy. During the middle age, purgation therapy is classified into several subtype; hydrogogue therapy, laxation with lubricants, purgation with cold-natured drugs and purgation with warm-natured drugs. Comparing with the ancient times, it must be a progression. It was investigated earnestly by a school leaded by Zhang Congzheng. They were not restricted to several diseases, but applied it to the wide range of diseases. They thought as following. 'One is ill from pathogenic factor so that you should eliminate it from the human body'. Hence, they frequently used three major remedies such as diaphoresis, emesis and purgation. In this process, purgation therapy had showed eye-opening progress. But opposition to it was not little. Li Gao was a representative man on the opposite side. He expressed a critical opinion and placed great importance on the genuine energy, the natural healing force. Under his influence, a large number of doctors evaded purgation and put it under taboo. On account of these trend, purgation therapy had took a backward step and retrograded. Therefore cathartics such as Rhei Radix et Rhizoma, Rharbitidis Semen, cold drugs such as Gypsum Fibrosum, etc. had been excluded for preservation of the genuine energy, and came about an obnoxious custom to value only 'tonity deficiency', or 'warm and tonify'. As it had came into fashion to approach most disease from the point of view, purgation therapy was merely fall into a remedy of constipation. After the eighteenth century purgation therapy encountered the new period of rivival. It was introduced by them who strived for the study of Epidemics to the new current of thought, so called '增水行舟'. It was because 온병 was apt to dissipate one's Yin fluid. Therefore purgation therapy of this period was characterized by establishing nourishment Yin and body fluid with or without use of timely purgation of accumulation of heat. From the time of Zhang Congzheng, it was accomplished by Lee Je-ma to the most epoch-making change. He caused an improvement in the use of purgation therapy by regarding innate constitutional contradiction as importance than representing clinical symptoms. He warned that existing remedies that depend only upon symptoms and signs, not upon individual characteristics including constitutional features didn't bring round to but kill them. And he understood all the pathologic processes in his constitutional theory, investigated specific drugs on four constitution, made indications of each prescriptions clear. For giving to differentiation of constition before differentiation of syndrom, his new slant on the pathologic phenomena overcome the limitations of 변증시치, and revaluate purgation therapy from remedy impaire the genuine energy to that restore it by recover the balance between the internal organ. It is the product of him to fundamentally upset the cause to be in disregard of purgation therapy.