• Journal of the Korean Chemical Society
• /
• v.23 no.6
• /
• pp.392-395
• /
• 1979

Some alkyl or aryl halides, such as ethyl bromide, butyl chloride, phenyl bromide and benzyl chloride, were reacted by Grignard's method with anhydrous tin tetrachloride in hydrocarbon media. When small amounts of ether were added into the Grignard reaction step, the reaction proceeded rather smoothly and gave good yields of corresponding organotin compounds.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1995.05a
• /
• pp.784-789
• /
• 1995

핵융합로 제1벽재로서 주목받고 있는 저방사화 Fe-Cr-Mn-W계 오스테나이트 스테인리스강에 소량의 V을 첨가하고 그 기본 조성에 시그마상의 생성억제와 합금의 고온강도 향상에 효과가 있는 질소함량을 변화시켜 전보에서 보고한 소둔열처리의 영향에 이어 미세 조직 특성 및 부식 저항성에 미치는 시효열처리의 영향을 살펴보았다. 부식저항성 평가를 위해서는 양극분극시험, 침지시험 수소취성 시험을 행하였으며, 석출상의 생성양상을 살펴보기 위해서는 광학현미경 관찰, 자성측정, EPR시험 및 경도시험을 행하였다. 시험결과, 질소의 함량이 증가할수록 시그마상의 석출이 억제되는 것을 알 수 있었으며, 시효시 실험합금의 부식저항성은 주로 $600^{\circ}C$부근에서 오스테나이트상의 입계에 석출하는 크롬탄화물과 50$0^{\circ}C$부터 비교적 넓은 온도 구간에 걸쳐 페라이트상으로부터 석출 변태되는 시그마상에 의해 지배되고 있음을 알 수 있었다.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2009.10a
• /
• pp.109-110
• /
• 2009

실리카와 폴리아닐린의 core-shell 복합체 나노입자를 실리카 나노입자 분산용액을 이용하여 제조하였다. 제조된 복합체 나노입자를 전기변색박막의 소재로 이용하기 위하여 알코올 용액에 분산하였고, 분산된 용액에 Tetraethoxysilane (TEOS)를 소량의 HCl 용액과 함께 첨가하여 코팅 용액을 제조하였다. 코팅 용액을 인듐주석산화물(ITO) 박막이 도포된 유리 기판위에 도포하고 열처리 하여 매우 높은 부착력을 갖는 전기변색박막을 얻을 수 있었다.

• Journal of the Economic Geographical Society of Korea
• /
• v.1 no.1
• /
• pp.57-74
• /
• 1998

Recently. the interest in Physical distribution has increased in economic geography This paper aims to review and prospect the internatonal physical distribution studies of international trade and international freight flows. And it has examined the changes in methodology of international physical distribution. Author has defined international physical distribution as the physical distribution of international trade and international freight flow The results are as follows : (1) As the methodology of international physical distribution studies developes, the physical distribution should be recognized not only as transportation phenomenon but also as total logistics which is understood as the combination of production and consumption including information flow. (2) The studies about model of international physical distribution flow ill need to study regional relations including urban, in the future. And economic geography and location theory adding culture and behaviour elements will be restructured, because not only state but also multinational corporation appear as trade subject in global economy. (3) The studies for the relation of habor and its hinterland in Physical distribution need to analyze the factors causing habor use with decision-making behaviour of corporation. (4) After oil crisis. as air freight is important, the studies for hinterland and foreland of freight centering international airport are needed because of necessity of light and small freight. flexible Production system, free trade, and high speed freight transportation of freshing food and flowers and so forth.

• Journal of the Korean Magnetics Society
• /
• v.21 no.1
• /
• pp.37-41
• /
• 2011

Fe compounds of scoria samples distributed in Songdang-ri positioning north-eastern area of Jeju island were investigated by means of X-ray diffractometry (XRD) and $^{57}Fe$ M$\ddot{o}$ssbauer spectroscopy. The samples were prepared from six parasite. We found that the samples were composed of a typical olivine, pyroxene, ilmenite, $SiO_2$, anorite and anorthoclase, M$\ddot{o}$ssbauer spectrum of the most scoria samples are shown doublets and sextets of olivine, doublets of pyroxene, ilmenite and silicate minerals. And the valence states of Fe ion of the scoria samples in this area are chiefly 3+ charge state and a little 2+ charge state.

• Journal of the Korean Chemical Society
• /
• v.22 no.1
• /
• pp.37-44
• /
• 1978

The effect of lithium chloride on the borane reduction of organic compounds was studied for three ketones, seven acid derivatives, three epoxides and cyclohexene in tetrahydrofuran at $0^{\circ}$. When compared with borane itself, borane-lithium chloride system enhanced the rates of reductions markedly of 2-heptanone, acetophenone, benzoyl chloride, phthalic anhydride, and three epoxides, whereas the reductions of benzophenone, four esters and cyclohexene showed little or no effect. $BH_3$-LiCl (1 : 0.1) reduced styrene oxide in 2 hr at $0^{\circ}$ to give 94.2 % yield of alcohols, 1-to 2-phenylethanol ratio being 60.8 to 39.2. And in the reduction of cyclohexene oxide, $BH_3$-LiCl (1 : 0.1) gave a quantitative yield of cyclohexanol in 2 hr at $0{\circ}$, however $BH_3$-LiCl (1 : 1) gave 58 % cyclohexanol and 42 % 2-chlorocyclohexanol. In the reduction of cyclohexene oxide, lithium nitrate showed no rate enhancement even when the salt was added in large excess. A formation of lithium chloroborohydride in the$BH_3$-LiCl system is suggested.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 1998.05a
• /
• pp.22-22
• /
• 1998

304 는 BWR(boiling water reactor)의 reactor 구조용 재료로 사용되고 있고, 합금 600 은 PWR(pressurized water reator) 의 증기 발생기 세관으로 쓰이고 있으며 모두 약 $280{\;}^{\circ}C$ 이상 의 원자로 냉각수에 노출되어 있다. 원자로 냉각수 분위기에서 두 합금의 공통적인 특정은 입계응력부식균열(IGSCC)에 민감한것과 IGSCC가 예민화(sensitization)와 관련이 있는 것이 다. 두 합금에서 일어나는 IGSCC는 원자력발전소의 부식피해중 가장 빈도가 높고 발생시 방사능 누출로 인하여 원전의 신뢰성을 저하시키고, 가동중단으로 인한 경제적 손실을 초 래하여 지난 20 년 동안 가장 심도있게 연구된 주제다. 304 은 크롬 탄화물의 업계 석출로 언하여 예민화된경우 IGSCC 에 민감한 반면 600 은 예민화된 경우 뿐만 아니라 용체화처리된 상태에서도 IGSCC에 민감하다. 오히려 600은 용 체화처리 후 700 C에서 15~20시간 시효처리를 하여 크롬탄화물을 업계에 석출 시커었을 때 IGSCC 저항성이 향상된다. 두 합금의 IGSCC 특정 중 큰 차이는 304는 임계균열전위 ( (critical cracking potential) 이 존재하여 부식전위(corrosion potential) 가 엄계균열전위보다 낮 은 경우 IGSCC 가 일어나지 않지만 그 반대인 경우 IGSCC 에 민감하게된다. 반면에 600 은 뚜렷한 임계균열전위가 존재하지 않고 양극 분극(anodic polarization) 뿐만 아니라 음극분극 시에도 IGSCC 가 일어난다. 이련 이유로 600의 IGSCC 가구로 피막파괴-양극용해(film rupture-anodic dissolution)외에 수소취성(hydrogen embrittlement)기구도 제안되고 었다. 원전의 냉각수는 고 순도의 물이지만 수 처리 과정과 웅축기 배관의 누수로 인한 산소, $Cu^{2+},{\;}S_xO_6{\;}^{2-}(x=3~6)$ 등이 유입되어 오염되는데 이려한 오염물질들이 수 ppm정도 소량 포함된 경우 응 력부식민감도는 상당히 증가된다. 산성분위기 흑은 산소, $Cu^{2+}$, 등이 소량 포합된 산화성 분위기 그리고 sufur oxyanion 에 오염된 고온의 물에서 600 의 IGSCC 민감도는 예민화도가 증가할 수록 민감하여 304 의 IGSCC 와 매우 유사한 거동을 보인다. 본 강연에서는 304 와 600 의 고온 물에서 일어나는 IGSCC 민감도에 미치는 환경, 예민화처리, 합금원소의 영향을 고찰하고 이에 대한 최근의 연구 동향과 방식 방법을 다룬다.

• Journal of the Korean Magnetics Society
• /
• v.17 no.5
• /
• pp.205-209
• /
• 2007

It have been investigated the measured results of the XRF, the X-ray diffractometry and $^{57}Fe\;M{\ddot{o}}ssbauer$ spectrum for scoria samples which are distributed throughout different areas in Mid-mountain Area of Jeju island. We consider that the scoria samples are chiefly made of silicate minerals, like $SiO_2$, others silicate minerals and iron oxides minerals. We study that it's materiel is consisted of olivine, pyroxene, ilmenite, hematite and magnetite. Iron compounds in that are $Fe^{2+}$ of olivine, pyroxene, ilmenite and $Fe^{3+}$ of hematite, magnetite et al. The major Fe fractions of the scoria samples are 51.77 wt%, so Fe fractions of the scoria samples are almost 3+ charge state with a little of the 2+ charge state.

• Journal of the Korean Magnetics Society
• /
• v.18 no.5
• /
• pp.168-173
• /
• 2008

Fe compounds of scoria distributed in northern area of Jeju island are investigated using X-ray fluorescence spectroscopy, X-ray diffractometry, and $^{57}Fe$ Mossbauer spectroscopy. The samples were prepared from four parasite volcanos. These samples consist of the typical basalt comprised of $SiO_2,\;Al_2O_3$, Fe compounds, and silicate minerals. The $M{\ddot{o}}ssbauer$ spectra showed doublets for olivine, pyroxene, and ilmenite as well as sextets for hematite and magnetite. The valence state of Fe is chiefly a 3+ charge state with a little 2+ charge state. It is expected that this results will add to the body of information related to the information mechanism of Jeju island. The geochemistry for these samples is the same results to mid-mountain's samples in Jeju Island.

• Journal of the Korean Ceramic Society
• /
• v.35 no.1
• /
• pp.55-65
• /
• 1998

The oxidation behavior of Ag-36.8a%Cu-7.4at%Ti alloy brazed on Si3N4 substrate was investigated at 400, 500 and 600$^{\circ}C$ in air. Under this experimental condition Si3N4 and Ag were not oxidized whereas Cu and Ti among the brazing alloy components were oxidizied obeying the parabolic oxidation rate law. The activation energy of oxidation was found to be 80kj/ mol which was smaller than that of pure Cu owing to the presence of oxygen active element of Ti. The outer oxide scale formed from the initial oxidation state was always composed of Cu oxides which were known to be growing by the outward diffusion of Cu ions. As the oxidation progressed the concentration gradient occurred due to the continuous consumption of Cu as Cu oxides and consequently build-up of an Ag-enriched layer below the Cu oxides resulted in the formation of multiple oxide scales composed of Cu oxide (CuO) /Ag-enriched layer/Cu oxide (Cu2O) /Ag-enriched layer. Also the inward diffusing of oxygen through Cu oxide and Ag-enriched layers led to the formation of internal oxides of TiO2.