• Korean Journal of Materials Research
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• v.22 no.11
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• pp.591-597
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• 2012

For heat exchanger applications, 2-ply clad materials were fabricated by rolling of aluminum (Al) and mild steel sheets. Effects of annealing temperature on interface properties, especially on inter-layer formation and softening of strain hardened mild-steel, for Al/mild steel clad materials, were investigated. To obtain optimum annealing conditions for the Al/mild steel clad materials, annealing temperature was varied from room temperature to $600^{\circ}C$. At the annealing temperature about $450^{\circ}C$, an inter-layer was formed in an island-shape at the interface of the Al/mild steel clad materials; this island expanded along the interface at higher temperature. By analyzing the X-ray diffraction (XRD) peaks and the energy dispersive X-ray spectroscopy (EDX) results, it was determined that the exact chemical stoichiometry for the inter-layer was that of $Fe_2Al_5$. In some samples, an X-layer was formed between the Al and the inter-layer of $Fe_2Al_5$ at high annealing temperature of around $550^{\circ}C$. The existence of an X-layer enhanced the growth of the inter-layer, which resulted in the delamination of the Al/mild-steel clad materials. Hardness tests were also performed to examine the influence of the annealing temperature on the cold deformability, which is a very important property for the deep drawing process of clad materials. The hardness value of mild steel gradually decreased with increasing annealing temperature. Especially, the value of hardness sharply decreased in the temperature range between $525^{\circ}C$ and $550^{\circ}C$. From these results, we can conclude that the optimum annealing temperature is around $550^{\circ}C$ under condition of there being no X-layer creation.

• Nuclear Engineering and Technology
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• v.4 no.4
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• pp.306-321
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• 1972

Molecular reorientation in (NH$_4$)$_2$SO$_4$, has been studied by cold neutron scattering. For T=300$^{\circ}$K data, the isolated quasielastic spectra and form-factors at various scattering angles are compared with four reorientational models based on SKOLD theory. Front these, it is concluded that the NH$_4$ions are performing either 3-fold four axes or 2-fold three axes reorientation with $\tau$$_{c}$=2.0$\times$10$^{-11}$ sec. The temperature dependence of f. is studied over 100$^{\circ}$K-413$^{\circ}$K and for the high-temperature phase, the widths of composite spectra are compared with the results from NMR relaxation measurements. All the results have shown that the neutron scattering method is capable of giving detalis of the reorientational modes in solids and therefore some discussions are given on the application of this method. A study of the form-factor is applied for NH$_4$I (Phase I) by comparing the measurement with the calculation based on free rotation approximation and proposed a reorientation model of NH$_4$ ions in the octahedral potential cage with $\tau$$_{c}$$\leq$10$^{-12}$ sec. Also a brief theoretical prediction for the effect of reorientational motions on the inelastic spectrum is discussed.sed.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.4
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• pp.763-770
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• 1997

The air abrasive technique is a non-mechanical method by which teeth are treated before restoration and stains and calculi are removed from tooth surfaces using the kinetic energy of small particles. The air abrasive technique in dentistry was first introduced in the 1950's with as instrument called 'Airdent'. But, as the main restorative materials of the period were amalgam and gold, and the instrument's inability to control the flow of particles caused the particles to be spread throughout the clinics, widespread use was not possible. In the 1990's, as these techincal problems were solved and more interest in new restorative materials rose in an effort to preserve sound tooth structure, new developements took place in instruments related to the air abrasive technique. The air abrasive technique produces less pressure, vibration and heat that might cause patient discomfort and facilitates the preservation of sound tooth structure. It also reduces the need for anesthesia and is less harmful to the pulp. Other advantages include increase in dentin bonding strength of composite resin, lower possibility of saliva contamination and maintenance of a dry field. But there is not direct contact between the nozzle and the tooth, the operator cannot use his or her tactile sense and must rely solely upon visual input. Other disadvantages are: the tooth preparation depends on the operator's ability; alpha-alumina particles, after bouncing off the tooth surface, cause damage to dental mirrors; the equipment is expensive and takes up a certain amount of space in the clinic. The author conducted case report using the air abrasive technique on patient visiting the Department of Pediatric Dentistry at Seoul National University Dental Hospital and arrived at the following conclusions. 1. The tooth preparation capability of different air abrasive devices varied widely among manufacturers. 2. It was more effective in treating early caries lesions and stains compared to lesions where caries had already progressed to produce soft dentin. 3. The cold stream and noise caused by the evacuation system was a major cause of discomfort to pediatric patients. 4. As there is no direct contact with tooth surface when using the air abrasive technique for tooth preparation, considerable experience and skill is required for proper tooth preparation.

• Journal of Haehwa Medicine
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• v.9 no.1
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• pp.745-761
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• 2000

Literatural study for Delirious speech and Fading murmuring, the results were as follows. 1. Delirious speech and Fading murmuring are given at the speech impediment. Derious speech to be out of language's order and slur the end of his words, and Fading murmuring is to repeat in losing conscious. 2. In constrast with Delirious speech and Fading murmuring, Maniac speech is induced by a general term for manic-depressive psychosis. Luoyan is to say in a feeble voice and mumble in a sleeping condition, and Paraphasia and Solioquy are appeared in a clear mental condition. The speech impediment is caused by damages of the nervous system and speech organ, and Yuyancuoluan is appeared in a feverless condition. 3. The symptoms of Delirious speech are to utter ravings and have a loud and heavy voice, and these resemble the delirium which specially has a speech impediment and muddle in the western medical world. The symptoms of Fading murmuring are to speak ambigously, repeatedly, and illogically and so are similar to the Wernicke dysphasia which is caused by a incomprehensible conversation. 4. The causes of Delirious speech are to spread a stomach heat and the lungs pathogenic qi into heart, not to sweat in cold damage, the Three Yang Combination of syndrome, stomach repletion, yang collapse due to excessive sweat, diarrhea, after diarrhea, heat to enter the blood chamer, feces to remain in the stomach, stasis blood to enter the viscera, to carry anger to extremity, and to be constipated. the cause of Fading murmuring is to despair vacuity desertion of vital essence and energy after a serious illness. 5. The causes of delirium are general infection, postoperative states, and metabolism disorders and those of Wernicke dysphasia are disorders of the blood vessel, brain tumors and traumas. 6. Delirious speech is cured with the discrimination of vacuity and repletion. Baitong Tang(白通湯), Chaihu Guizhi Tang(柴胡桂枝湯), Chaihu Jia Longgu Muli Tang(柴胡加龍骨牡蠣湯) are prescribed in case of vacuity, while Chengqi Tang(承氣湯), Baihu Tang(白虎湯), Liangge San(凉膈散) are in case of repletion. Fading murmuring is treated with Xiao Chaihu Tang(小柴胡湯), Fuzi Tang Jiawei(附子湯加味), Shengmai San(生脈散), and Renshen Sanbai Tang(人蔘三白湯). 7. To acupunture Qimen-Xue(期門穴) is required when it is late to prescribe a medical decoction or the hyperactive liver qi attacking the spleen.

• Journal of the Korean GEO-environmental Society
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• v.17 no.1
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• pp.5-12
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• 2016

Investigation of in-situ ground in cold region is difficult due to low accessibility and environmental factors. In this study, correlation between dynamic cone resistance and shear strength is suggested to estimate the strength of frozen soils by using instrumented dynamic cone penetrometer. Tests were conducted in freezing chamber after preparing sand-silt mixture with 2.3% water content. Vertical stresses of 5 kPa and 10 kPa were applied during freezing, shearing, and penetration phase to compare the dynamic cone resistance and shear strength. The dynamic cone resistance, additionally, is calculated to minimize the effect of energy loss during hammer impact. Experimental results show that as the shear strength increases, the dynamic cone penetration index (DCPI) decreases nonlinearly, while the dynamic cone resistance increases linearly. This study provides the useful correlation to evaluate strength properties of the frozen soils from the dynamic cone penetration and direct shear tests.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.4
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• pp.8-16
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• 2004

The industrialization of central Europe more than 100 ago marked the beginning of densely concentrated buildings in quickly growing cities. A cheap type of roofing material of that time was tar. But it was dangerous because it was high inflammable. Then some roofer had a splendid idea. They used sandy material as a final layer atop the impermeable tar layer. These roofs were much more fire resistant than the typical roofs. In this sandy layer some plant species began to grow spontaneously. This was the beginning of the green roof history of modern Europe. A number of these green roofs survived both world wars. In the early 80's in Berlin alone, 50 such buildings existed and they continued to be waterproof until the present day. Since the 1992 Earth Summit of 1992 in Rio de Janeiro(http://www.johannesburgsummit.org/html/basic_info/unced.html) the term "sustainable development" became of central interest of urban designers. In city regions green roofs had become synonymous with this term. With a small investment, long-lasting roofs can be created. Further back in history, more exciting examples of green roofs can be found. The hanging gardens of antiquity are well-known. There are also green roofs built as insulation against cold and heat all over the world. For over 20 years, roof greening in central Europe has been closely examined for various reasons. Roof greening touches several different disciplines. Of primary interest is the durability of the roofs. But ecologists are also interested in green roofs, for instance in biodiversity research. The beneficial effect of greening on water proofing was also proven. For some time, the issue of fire protection was investigated. According to tests, green roofs received a harsh careful rating. Their fire protective property is considered similar to that of tile roofs. Another recent impulse for the green roof movement in Germany has come from the evident improvement of storm water retention and the reduced burden on the sewer system. The question of whether and how much energy green roofs can save has become an urgent question. The state of the research and also various open questions from a central European point of view will be discussed in the context of international collaboration. Apart from academic considerations, those who involve themselves in this issue take a predominantly positive view of the numerous existing green roofs in Germany. In some cities, green roofs are the typical construction technique for new buildings. A few outstanding examples will conclude this review. In Germany, about 20 companies, some of which operate internationally, specialize in green roof consulting. Learning from each other in an open-ended way with respect to different construction techniques and applications in various climatic regions can only be accomplished through such international collaboration as is taking place here.

• Journal of the Korean Institute of Gas
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• v.6 no.1 s.17
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• pp.38-45
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• 2002

Hydrates are solid cryctallines resembling ice in appearance, which are consist of a gas molecule surrounded by a cage of water molecules. Because of containning a large amount of methane, hydrates have been considered as a future energy resource. However, the formation of hydrates in the oil and gas industries has been known as a serious problem for a long time. The formation of hydrate in pipeline is common in seasonally cold or sub-sea environments with low temperatures and high pressures. Especially, hydrate plug formation becomes a real menace to flow assurance in inadequately protected transmission lines. This study was carried out for the purpose of understanding mechanism of hydrate plugging and examining formation conditions of hydrate in high pressure gas pipeline. In this study, we measured hydrate equilibrium conditions under the various flowing conditions with the methane. The results were presented both the plugging tendency and the effect of flowing velocity.

• Korean Security Journal
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• no.42
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• pp.229-249
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• 2015

As the post-cold war era and globalization go on, national security problems which were not traditional national security problems such as terrorism, crime, environmental disasters, economic crises, cyber-terrorism, diseases, and energy problems threat humanity and nations and demands changes. Also, with the change, the concept of "big government" has emerged as the role of nation expanded. The modern society sees every country change from small government to big government in order to realize the establishment of welfare state. A comprehensive interpretation of security is needed in order to comprehensive protection of citizens beyond outside invasion such as crime, new disaster, terrorism. In Korea, incidents such as Cheonan-Ham, Yeonpeyong-Do, foot-and-mouth disease, Ddos terrorism, pirates hostages, mad cow disease, AI are happening and the humanitarian support for North Korea and the summit of South and North Korea are at a standstill. Also, National emergency management system, comprehensive emergency management center, countrol tower, national security system, cooperation with citizens, establishment of legal and institutional system are needed. The importance of this research is on the reestablishment of new national security and emergency management system according to the comparison between the national security and counter-terrorism system of Korea and that of the United States which is a leading country in this field. Also, the establishment of national emergency management act is needed as a statute for effective function as currently various laws and administrative organizations are dispersed.

• Korean Journal of Poultry Science
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• v.32 no.4
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• pp.239-244
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• 2005

Uncoupling protein(UCP) is expressed exclusively in brown adipose tissue(BAT). It is blown to uncouple phosphorylation from oxidation and hence to be involved in energy metabolism and heat production, especially under cold exposure. In the present study, we identified single nucleotide polymorphism(SNP) in exon 3 of avUCP gene in Korean native chicken(KNC) population. It was detected a SNP T+1316C in exon 3 of avUCP gene by sequence analysis in KNC population. For PCR-RFLP analysis of the SNP T+1316C, used by AP III restriction enzyme. The result of PCR-RFLP analysis showed that allele T has two fragments of 255 bp and 86 bp, and allele C has only one fragment of 341 bp. The genotype frequencies were TT type, 0.7875; TC type, 0.1875 and CC type, 0.025; and the frequencies of allele T and C were 0.881 and 0.119, respectively in KNC population. Next study was conducted to investigate the effect of the SNP in avUCP gene on economic traits in the KNC population. The TT genotype had a significant higher daily percent lay(84.61) than CC genotype(p<0.05) in KNC population. This study may be useful for genetic studies of avCUP gene and selection on daily percent lay of KNC.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.982-982
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• 2012

본 연구에서는 우리나라의 중 소규모 유역의 수문학적 위험도 분석을 위하여 한강유역을 대상으로 통합위험지수(IRI: Integrated Risk Index)를 산정하였으며, El Ni$\tilde{n}$o-Southern Oscillation (ENSO)에 의한 대규모 대기순환 패턴의 변화가 한강 유역의 통합위험지수 변화에 미치는 영향을 평가하였다. ENSO자료는 전통적인 El Ni$\tilde{n}$o에 해당하는 Cold-tongue (CT) El Ni$\tilde{n}$o와 중앙태평양 부근의 이상적인 해수면 온도 상승에 의한 Warm-pool (WP) El Ni$\tilde{n}$o, 그리고 해수면 온도가 이상적으로 낮게 관측되는 La Ni$\tilde{n}$a 기간으로 구분하였으며, 각 기간 중 가장 강한 ENSO가 발생한 해(CT El Ni$\tilde{n}$o, 1998; WP El Ni$\tilde{n}$o, 2005; La Ni$\tilde{n}$a, 2000)를 대상으로 통합위험지수를 산정하였다. 통합위험지수는 수문학적 요인(Hydrologic Components), 사회 경제적 요인(Socio-Economic Components)과 생태적 요인(Ecological Components)으로 구분하였고, 엔트로피(entropy) 기법을 통하여 각 인자와 요인별 가중치를 적용하였다. 중권역별 통합위험지수의 평가는 5개의 계급구간(Very High, High, Medium, Low, Very Low)으로 구분하였다. 분석결과, CT El Ni$\tilde{n}$o해의 유역평균 IRI 값은 0.58, WP El Ni$\tilde{n}$o해의 IRI 값은 0.57로 비슷한 결과를 보였으나, La Ni$\tilde{n}$a해에는 IRI 값이 0.41로 낮게 나타났다. CT와 WP El Ni$\tilde{n}$o해에는 한강 서쪽일부 중권역에서 통합위험지수가 높게 나타났으며, La Ni$\tilde{n}$a해에는 한강 중 동부 대부분 유역에서 낮게 분석되었다. 향후 유역별 통합위험지수 산정과 더불어 서로 다른 형태의 ENSO에 따른 수자원 변동 예측이 이루어진다면, 수자원의 효율적인 관리와 안정적인 용수공급에 도움을 줄 것으로 사료되며, 이는 유역별 수자원의 취약성 평가 및 위험도 분석을 위한 기초자료로 활용이 가능하리라 사료된다.