• 자원환경지질
• /
• 제42권3호
• /
• pp.177-193
• /
• 2009

삼광광상은 선캠브리아기 경기육괴의 화강편마암내에 발달된 단열대(NE, NW)를 따라 충진한 8개의 괴상맥으로 구성된 중열수 석영맥광상이다. 이 광상의 광화작용은 여러번의 단열작용에 의해 형성된 두시기의 석영+방해석시기(광화I시기)와 방해석시기(광화II시기)로 구성된다. 광화I시기의 열수작용에 의한 변질작용은 견운모화, 녹니석화, 탄산염화, 황철석화, 규화, 및 점토화작용등이 관찰되며 견운모대는 석영맥과 접촉한 부분에서 녹니석대는 석영맥으로부터 멀어짐에 따라 관찰된다. 견운모대의 모암변질광물은 대부분이 견운모 및 석영이며 일부 일라이트, 탄산염광물, 녹니석으로 구성된다. 녹니석대의 모암변질광물은 주로 녹니석, 석영과 소량 견운모, 탄산염광물 및 녹염석으로 구성된다. 견운모의 Fe/(Fe+Mg) 값은 0.45${\sim}$0.50(0.48$\pm$0.02)이며 백운모-펜자이트족에 해당되고 녹니석의 Fe/(Fe+Mg) 값은 0.74${\sim}$0.81(0.77$\pm$0.03)이고 대부분 브런스비자이트에 해당된다. 견운모와 녹니석에 대한 $Al_{IV}$-FE/(FE+Mg)의 다이어그램은 변질시 같은 광종의 견운모와 녹니석의 형성온도를 나타내는 지시자로써 유용하다. 이것은 계산된 녹니석 단종의 활동도가 $a3(Fe_5Al_2Si_3O_{10}(OH)_6$=0.0275${\sim}$0.0413, $a2(Mg_5Al_2Si_3O_{10}(OH)_6$=1.18E-10${\sim}$7.79E-7, $a1(Mg_6Si_4O_{10}(OH)_6$=4.92E-10${\sim}$9.29E-7로서 삼광광상의 녹니석은 iron-rich 녹니석으로 비교적 고온 (T>450$^{\circ}C$에서 모암과 평형상태에서 온도가 감소함에 따라 형성되었음을 알 수 있다. 모암변질시 ${\alpha}Na^+$, ${\alpha}K^+$, ${\alpha}Ca^{2+}$ 및 ${\alpha}Mg^{2+}$는 각각 ${\alpha}Na^+$=0.0476($400^{\circ}C$), 0.0863($350^{\circ}C$), ${\alpha}K^+$=0.0154($400^{\circ}C$), 0.0231($350^{\circ}C$), ${\alpha}Ca^{2+}$=2.42E-11($400^{\circ}C$), 7.07E-10($350^{\circ}C$), ${\alpha}Mg^{2+}$=1.59E-12($400^{\circ}C$), 1.77E-11($350^{\circ}C$)이며 열수용액의 pH는 5.4${\sim}$6.4($400^{\circ}C$), 5.3${\sim}$5.7($350^{\circ}C$)로서 모암변질시 열수용액는 약산성이었음을 알 수 있다. 모암변질시 이득원소(부화원소)는 $TiO_2$, $Fe_2O_3(T)$,CaO, MnO, MgO, As, Ag, Cu, Zn, Ni, Co, W, V, Br, Cs, Rb, Sc, Bi, Nb, Sb, Se, Sn 및 Lu 등이며 특히 대부분의 광상에서 Ag, As, Zn, Sc, Sb, S,$CO_2$ 등의 원소가 현저하게 증가하므로 중열수 및 천열수 금-은광상의 탐사에 지시원소로서 활용될 수 있을 것이다.

• 한국재료학회지
• /
• 제19권10호
• /
• pp.527-532
• /
• 2009

The electrochromic properties of Au nanoparticles (NPs) incorporating poly (3, 4-ethylenedioxythiphene) (PEDOT) film were investigated. Trisodium citrate was used for stabilizing Au NPs to control the size. The capping molecules of the Au nanoparticles were exchanged from citrate to 2-mercaptoethanol (2-ME). Water was removed by centrifuge and Au NPs were redispersed in methanol (MeOH). Finally, we obtained ca. 11.7 nm diameter of Au NPs. The effects of 0.15 at% of Au NPs incorporation on the optical, electrical, and eletrochromic properties of PEDOT films were investigated. The electrical property and switching speed of Au/PEDOT film was slightly improved over that of PEDOT film because Au NPs play a hopping site role and affect packing density of the PEDOT chain. Through the ultra violet-visible spectra of PEDOT and Au/PEDOT films at -0.7 V (vs Ag/AgCl), blue shift of maximum absorption peak was observed from PEDOT (585.4 nm) to Au/PEDOT (572.2 nm) due to a shortening of conjugated length of PEDOT. The Au NPs interfered with the degree of conjugation and the maximum absorption peak was shifted to shorter wavelength.

• 한국균학회지
• /
• 제30권2호
• /
• pp.113-118
• /
• 2002

S. rugosoannulata의 배양액으로부터 4단계를 거쳐 분자량이 54 kDa인 CMCase를 분리 정제하였다. 이 효소는 pH 4.0에서 최대의 활성을 보여주는 acidic CMCase로 $40^{\circ}C$에서 최대활성을 나타냈다. EDTA에 의해 활성이 저해되는 것으로 보아 metalloenzyme으로 추정되며 1,10-phenanthroline과 KCN 및 L-cystein 등의 저해제에 효소활성이 크게 감소하였으며, $AgNO_{3},\;MgSO_{4},\;KCl$등의 금속염에서는 효소활성이 증가되었으나, $ZnSO_{4},\;BaCl_{2},\;CaCl_{2}$ 등에서는 효소활성이 저해되었다.

• Natural Product Sciences
• /
• 제15권4호
• /
• pp.198-202
• /
• 2009

Based on the use of Acorus gramineus SOLAND (AG) for the treatment of stroke in traditional Korean medicine, the present study was carried out to evaluate neuroprotective effects of ${\alpha}$-asarone after transient global cerebral ischemia using rat 4-vessel occlusion (4VO) model in rats. ${\alpha}$-Asarone (5 mg/kg) administered intraperitoneally significantly protected CA1 neurons against 10 min transient forebrain ischemia as demonstrated by measuring the density of neuronal cells stained with Cresyl violet. ${\alpha}$-Asarone significantly reduced hippocampal neuronal cell death by 85.2% where as its isolated single compounds from AG compared with a vehicle-treated group.

• 한국미생물·생명공학회지
• /
• 제20권4호
• /
• pp.401-408
• /
• 1992

Cholesterol oxidase를 생산하는 균주를 토양으로 분리하고 이를 배양하여 효소를 생산한 후 정제하여 그 특성을 조사하였다. 본 효소는 CH2 concentrator에 의한 농축, DEAE-cellulose chromatography, Superose 12 column FPLC로 정제하였고, 비활성이 약 31배나 증가하였다. 이 효소는 $50^{\circ}C$, pH 6.0에서 최대 활성을 나타냈고 30-$45^{\circ}C$ 범위에서는 안정하였다. pH에 대한 안정성은 pH 6.0-11.0까지 광범위한 안정성을 보였으며, Km 값은 cholesterol에 대해서 $3.65{\times}10^{-3}$M이며 분자량은 59,500 dalton으로 추정 된다. 또한 $Ca^{2+}$, $Ba^{2+}$, $Fe^{2+}$, Brij 35에 의해서는 효소의 활성이 저해되지 않았지만, $Hg^{2+}$, $Ag^{2+}$ 및 SDS에 의해서는 저해되는 것으로 나타났다.

• Macromolecular Research
• /
• 제10권2호
• /
• pp.80-84
• /
• 2002

Silver species other than the silver ion were formed by UV irradiation on polymer electrolyte membranes containing silver salts and their effect on complexation behavior between the silver and olefin was investigated through the separation performance of olefin/paraffin mixtures. The ideal propylene/propane separation factor reached 350 and the separation coefficient was ca.15 due to the high loading amount of silver ions into poly(2-ethyl-2-oxazoline) (POZ) without UV irradiation. On UV irradiation either in air or under nitrogen, the silver-POZ membranes became yellow-brown initially due to the formation of colloidal silver particles, and finally black and metal-like luster. Even when Ag$^{+}$ was converted, to some extent, to Ag$^{\circ}$ by UV irradiation in air at the early stage, the separation coefficient of olefin/paraffin mixtures was maintained. This suggests that silver species other than the silver ion is active for olefin carrier for facilitated transport. Meanwhile the steady decrease of the separation coefficient was observed in the silver/POZ membranes irradiated under $N_2$. It is suggested that the reduction of silver ions in POZ goes through a different photoreduction mechanism with UV irradiation depending on the environment.t.

• 한국식품과학회지
• /
• 제13권1호
• /
• pp.67-73
• /
• 1981

Streptomyces chibaensis로부터 분비하는 이눌라아제를 일연(一連)의 에탄올 침전, DEAE-cellulose 칼럽크라마토그래피 및 Sephadex-200 gel frltration 방법에 의(依)해서 120배 분리정체하였고 정제된 효소의 최적 pH는 6.5이고 pH $5.0{\sim}9.0$ 범위내에서는 비교적 안정성을 보였다. 효소는 $Mn^{++},\;Mg^{++}$ 및 $Ca^{++}$의 존재하에서는 약간 활성화되었고, $Hg^{++}\;Ag^{++}$의 존재하에서는 강한 비활성화를 보였다. 정제된 효소는 endo 형(型)으로 Km 값은 $4.54{\times}10^{-4}M$이었다.

• 한국초전도저온공학회:학술대회논문집
• /
• 한국초전도저온공학회 2003년도 학술대회 논문집
• /
• pp.120-122
• /
• 2003

We jointed Bi(Pb)-Sr-Ca-Cu-O multifilament tapes and evaluated their electrical properties. In order to improve connectivity of multifilarnents, single-filament tape was inserted between two multifilament tapes or multifilament was stepped by mechanical remove. The critical current ratio (CCR) and n-value of the jointed tapes were evaluated as a function of uniaxial pressure. It was observed that CCR and n-value were 24.8-29.0% and 2.5-2.8 for lap-jointed tape. On the other hand, the corresponding values were improved to 51.8-61.9% and 2.9-5.1 for three stepped jointed tape, and 63.4-67.9% and 3.4-4.2 for double MSM lap-jointed tape, respectively. These improvements are to be due to better interconnection between filaments of two tapes.

• Restorative Dentistry and Endodontics
• /
• 제17권2호
• /
• pp.287-306
• /
• 1992

The amounts of copper, mercury, silver, tin, and zinc released from conventional, dispersed phase and spherical high copper content amalgam immersed in artificial saliva soln. for periods of 2 hours, 1 day, 7 days, 30 days has been measured using Neutron Activation analysis and Atomic Absorption Spectrophotometry. The second electron image and EDX of the surface of samples immersed in artificial saliva were observed using SEM. The following results were obtained. 1. The dispersed non-$\gamma_2$ amalgam released more Hg, Ag than the $\gamma_2$-amalgams. Later a decrease of the release rate could be observed. 2. The dispersed high copper amalgam released more copper than low-copper amalgam and the release rate was decreased with time. But the amounts of copper released from Tytin increased with time. 3. Zinc was released all the experiment time. 4. EDAX showed that surface was composed of Ca,P, Sn, Ag, Zn, and Cu, but C1 was not detected. 5. The discontinued destructed surface was observed from the polished amalgam surface. High copper amalgam was destructed more than low copper amalgam.

• 전기화학회지
• /
• 제5권4호
• /
• pp.209-211
• /
• 2002

The simultaneous sensing of nitric oxide (NO) and its metabolite, nitrite $(NO_2^-)$ has been studied by Osteryoung square-wave voltarnmetery (OSWV) in physiological pH solution (0.1 M phosphate buffer solution, pH 7.2). Using an electrochemically pretreated glassy carbon (GC) electrode, OSWV was successfully applied to observe the well-separated oxidation peaks at ca. 0.58 and 0.80V vs. Ag/AgCI for NO and $(NO_2^-)$, respectively. This clear separation between the NO and $(NO_2^-)$ oxidation peaks may be due to the formation of surface oxides (e.g., quinone (C=O) or carboxylic $(COO^-)$ group) and surface defects introduced by the electrochemical pretreatment of GC electrodes.