• 한국신재생에너지학회:학술대회논문집
• /
• 2010.06a
• /
• pp.223.2-223.2
• /
• 2010

용융탄산염 연료전지(MCFC)는 $650^{\circ}C$에서 작동하는 고온형 연료전지 시스템이다. 이 시스템은 천연가스 등을 개질하여 생산된 수소를 바로 전기로 생산할 수 있는 시스템으로 열효율이 높으며, 현재 대체 발전시스템으로 각광을 받고 있다. MCFC는 개질방식에 따라 내부개질 방식과 외부개질 방식이 있다. 내부개질 방식은 수소를 생산하는 개질기가 스택내부에 장착된 형식으로 천연가스를 스택내부에서 개질하여 바로 전기를 생산하는 방식이다. 이 내부개질반응에 사용되는 촉매로는 알루미나에 담지된 니켈(Ni) 계열촉매이 주로 쓰이고 있다. 또한 내부개질촉매의 형태는 작은 원주형의 촉매형태로 성형되어 사용된다. 이 성형된 촉매의 크기가 바로 내부개질 스택의 크기를 결정하는 중요한 요소이다. 그래서 촉매의 크기는 되도록이면 작게 성형하는 것이 중요하다. 그러나 촉매의 크기가 너무 작으면 촉매를 성형하는데 큰 어려움이 생기게 된다. 본 연구에서는 니켈 촉매를 공침법이 아닌 균일용액침전법을 이용하여 제조하였으며, 이 촉매를 이용하여 지름이 약 2 mm 이하로 촉매를 압출성형하는 방법을 연구하였다. 먼저 요소(urea)를 이용한 균일용액침전법으로 촉매를 제조하였다. 최적의 촉매 합성조건을 살펴보기 위해서, 반응 온도를 80, 85, 90, 95, $100^{\circ}C$로 변화 시키면서 제조된 촉매의 특성을 살펴보았다. 그리고 촉매의 적절한 니켈 양을 알아보기 위해서 니켈의 양을 30, 40, 50, 60, 70 wt%로 변화 시켰으며, 조촉매로 사용되는 MgO 양을 5, 10, 15, 20 wt%로 변화 시켜서 제조된 촉매의 특성을 살펴보았다. 물성을 비교하기 위해서, X-선 회절분석(XRD) 및 TPR, 물리화학흡착을 하였다. 그 결과 침전반응온도가 $80^{\circ}C$에서 촉매가 가장 좋은 물성을 보였으며, 우수한 개질성능을 보였다. 그리고 촉매 활성물질인 니켈의 함량은 50 wt% 정도가 가장 적절한 함량이었으며, MgO의 함량이 15 wt%일 때 가장 우수한 물성과 개질 성능을 보여주었다. 이 촉매들은 공침법으로 제조된 상용촉매와 비교하였을 때, 보다 우수한 물성과 개질성능 보였다. 그래서 이 촉매를 균일침전법을 이용하여 대량으로 제조한 다음 압출성형 방법을 이용하여 촉매를 원주형으로 제조하였다. 먼저 제조된 촉매는 별도의 분쇄작업(볼밀 혹은 제트밀)을 거치지 않아도 입자사이즈가 약 $4{\mu}m$ 수준이 나오도록 촉매 제조조건을 조절 하였다. 그리고 소량의 Methyl cellulose(MC) 바이더와 물만 사용하여 촉매를 혼합한 다음 스크류 압출기를 이용하여 촉매를 성형하였다. 이 촉매는 지름이 약 2 mm 이하로 제조할 수 있었으며, 기계적 강도는 타정기로 성형한 상용촉매보다 우수하였다. 그리고 촉매 성능 또한 상용촉매와 비교하였을 때, 우수한 성능 보였다. MCFC용 내부개질 촉매로 균일용액침전법을 사용한 촉매가 적합하다고 판단되며, 압출성형에도 적합하다고 판단되었다.

• Proceedings of the Korean Vacuum Society Conference
• /
• 1998.02a
• /
• pp.24-24
• /
• 1998

반도체장비를 포함하는 초고진공장비의 園훌化가 급속히 그리고 절실히 요구되고 있는 것이 현실정이다. 當面해서 실현할 국산진공장비의 대상은 廣範圍하다. 즉, 각종 진공 pump ( (rotary, dry, diffusion, cryo, ion, turbo melecular pump), 진공 chamber, 진공 line, gate valve 를 위 시 한 진공 V머ve, flange, gasket, fl않d야lU, mainpulater 퉁 진공 部品이 다. 진공계 의 핵심 은 適切하고 優良한 진공재료의 선태파 사용이다. 진공장비는 사용자가 원하는 진공도를 원하 는 시간 동안 륨空度를 유지해 주어야 한다. 진공재료 선태의 기준사항은:(1) 기체의 透過성 (2) 薰했훌 (3) 혔體放出특성 - -outgassing과 degassing- (4) 機械的 량훌度 (5) 온도 의존성 (6) 化學톡성 (7) 加I성 및 鎔接 성 (8) 課電특성 (9) 磁氣특성 (10) 高速함子 및 放射線 특성 (11) 經濟성 및 調達생 둥이 다. 우량한 초고진공계재료는 풍부하게 개발되어 왔고, 또 新材料들이 개발되고 있다. 여기에서는 주로 초고진공 내지는 극고진공계의 構造材料, 機能材料, 部品材料 일반파 몇가지 신재료의 특 성에 관해서 記述한다. M Mild SteeHSAE, 1112, 1010, 1020, 1022, etc)., S Stainless SteeHAlSI, 304, 304L, 310, 316, 321, 347): 구조재료, chamber, fl하1ges A Aluminum과 Alloys (1060, 1100, 2014, 4032, 6(뻐1): 구조재료, chamber, flanges, gaskets A AI, Al 떠loy는 SS에 代替하는 역 할올 시 작하고 있다. C Copper, Copper Alloys(C11$\alpha$)0, C26800, C61400, Cl7200): 내장인자, gasket, cryopanel, tubing T Titanium, Ziriconium, Haf띠um 및 Alloys: 특히 Ti은 10n pump 용 getter material 이 외 에 U UHV,XHV용 chamber계로서 관심올 끌고 있다. N Nickel, Nickel Alloys (200, 204, 211, monel, nichrome): 부식 방지 , 전자장치 , 자기 장치 귀 금속(Ag, Au, Pt, Pd, Rh, Ir, Os, Ru): 보조부품, gasket, filament, coating, thermocouple, 접 합부위 T TiC, SiC, zrC, HfC, TaC 둥의 탄화물과, BN, TiN, AlN 동의 질화물, 붕화물이 둥장하고 었 다. 유리: Soda Lime, Borosilicate, Potash Soda Lead: View Port, Chamber envelope C Ceramics: AlZ03, BeO, MgO, zrOz, SiOz, MgOzSiOz, 3Alz032SiOz, Z$textsc{k}$hSiOz S상N4: e electrical, thermal insulators, crucibles, boats, single crystals, sepctr려 windows 저자는 최근 저자들이 발견한 Zr-Ti-Cu-Ni-Be amorphous alloys coated cham뾰r가 radiation p proof로 이용될 수 있는 사실을 점검하고 었다 .. Z.Y. Hua 들은 Cs3Sb를 새로운 photocathode 재료로 보고하고 있다.

• Economic and Environmental Geology
• /
• v.30 no.4
• /
• pp.279-289
• /
• 1997

Dark to pale green-colored, Cr-bearing sericites from hydrothermal alteration zone of the Narim gold deposit were investigated mineralogically and geochemically. The alteration zone is composed mineralogically of quartz, carbonate minerals and green sericite with minor amounts of chlorite, barite and sulfide minerals (pyrite, sphalerite, galena). The zone is enriched in As (967 to 1520 ppm), Cu (31 to 289 ppm), Ni (1027 to 1205 ppm), Pb (0.20 to 1.24 wt.%) and Zn (1.03 to 1.07 wt. %) compared with fresh rocks such as granitic gneiss, porphyritic biotite granite and basic dyke. The Cr, probably the chromophore element, is highly enriched in the alteration zone (1140 to 1500 ppm), host granitic gneiss (1200 ppm) and porphyritic biotite granite (1200 ppm). Occurrence and grain size of sericite are diverse, but most of the Cr-bearing sericites (150 to $200{\mu}m$ long and 20 to $30{\mu}m$ wide) occur along the boundaries between ore veins and host rocks (especially basic dyke and granitic gneiss). X-ray diffraction data of the sericite show its monoclinic form with unit-cell parameters of $a=5.202{\AA}$, $b=8.994{\AA}$, $c=20.103{\AA}$, ${\beta}=95.746^{\circ}$ and $V=935.83{\AA}^3$, which are similar with the normal 2M1-type muscovite. Representative chemical formula of the sericite is ($K_{1.54}Ca_{0.03}Na_{0.01}$)($Al_{3.42}Mg_{0.38}Cr_{0.14}Fe_{0.06}V_{0.02}$)($Si_{6.69}Al_{1.31}$)$O_{20}(OH)_4$. The Cr content increases with decrease of the octahedral Al content, and ranges from 0.36 to 2.58 wt.%. DTA and TG curves of the sericite show endothermic peaks at $342^{\circ}$ to $510^{\circ}$, $716^{\circ}$ to $853^{\circ}$ and $1021^{\circ}C$, which are due to the expulsion of hydroxyl group. The total weight loss by heating is measured to be about 8.8 wt. %, especially at $730^{\circ}C$. Infrared absorption experiments of the sericite show broad absorption band due to the O-H bond stretching vibration near the $3625cm^{-1}$, coupled with the 825 and $750cm^{-1}$ doublet. The vibration bands related with the H-O-Al and Si-O-Al bonds occur at $1030cm^{-1}$ and 500 to $700cm^{-1}$, respectively. Based on paragonite content of the sericite, the formation temperature of the Narim gold deposit is calculated to be $220{\pm}10^{\circ}C$.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.11
• /
• pp.1881-1890
• /
• 2016

Manganese superoxide dismutase (MnSOD) is a vital enzyme that protects cells from free radicals through eliminating superoxide radicals ($O^{2-}$). Hirudin, a kind of small active peptide molecule, is one of the strongest anticoagulants that can effectively cure thrombus diseases. In this study, we fused Hirudin to the C terminus of human MnSOD with the GGGGS linker to generate a novel dual-feature fusion protein, denoted as hMnSOD-Hirudin. The hMnSOD-Hirudin gene fragment was cloned into the pET15b (SmaI, CIAP) vector, forming a recombinant pET15b-hMnSOD-Hirudin plasmid, and then was transferred into Escherichia coli strain Rosetta-gami for expression. SDS-PAGE was used to detect the fusion protein, which was expected to be about 30 kDa upon IPTG induction. Furthermore, the hMnSOD-Hirudin protein was heavily detected as a soluble form in the supernatant. The purification rate observed after Ni NTA affinity chromatography was above 95%. The hMnSOD-Hirudin protein yield reached 67.25 mg per liter of bacterial culture. The identity of the purified protein was confirmed by western blotting. The hMnSOD-Hirudin protein activity assay evinced that the antioxidation activity of the hMnSOD-Hirudin protein obtained was $2,444.0{\pm}96.0U/mg$, and the anticoagulant activity of the hMnSOD-Hirudin protein was $599.0{\pm}35.0ATU/mg$. In addition, in vitro bioactivity assay showed that the hMnSOD-Hirudin protein had no or little cytotoxicity in H9c2, HK-2, and H9 (human $CD_4{^+}$, T cell) cell lines. Transwell migration assay and invasion assay showed that the hMnSOD-Hirudin protein could suppress human lung cancer 95-D cell metastasis and invasion in vitro.

• Korean Journal of Environmental Agriculture
• /
• v.23 no.3
• /
• pp.170-177
• /
• 2004

Agroenvironmental characteristics in paddy fields irrigated with the water of Nagdong river were analyzed along the river watershed for two years from 1999. The sites monitored from upper reaches of the river were Andong, Sangju, Gumi, Goryeong, Changnyeong, Milyang and Pusan. In paddy soils, the contents of heavy metals such as Cd, Cr, Cu, Pb, Ni, Zn and As were around natural values showing the highest values in Pusan followed by Goryeong. In brown rice, the contents of heavy metals were lower than natural values. Soil chemical properties appeared higher values in the lower reaches including Goryeong than the upper ones. The highest parameters in Goryeong were pH ($5.9{\sim}6.1$), EC ($0.8{\sim}0.9\;dS/m$), $Av.P_2O_5$ ($155{\sim}201\;mg/kg$), exchangeable Ca ($6.7{\sim}7.4\;cmol^+/kg$), Mg ($1.92{\sim}2.50\;cmol^+/kg$), K ($0.18{\sim}0.21\;cmol^+/kg$) and those in Pusan were organic matter ($23.0{\sim}29.1\;g/kg$) and T-N ($1.6{\sim}1.8\;mg/kg$). In conclusion, the recommended rates of N fertilizer for rice cropping were 21.4%, 11.8% and 8.8% high for Andong, Sangju and Gumi, respectively and 14.9%, 4.6%, 4.5% and 11.5% low for Goryeong, Changnyeong, Milyang and Pusan, respectively reflecting the chemical properties of soils and the quality of irrigation water on the basis of 110 kgN/ha. In the case of phosphorous, the rates were 18.9% and 33.3% low for Changnyeong and others, respectively on the basis of $45\;kgP_2O_5/ha$. The populations of bacteria, fungi, actinomycetes, Bacillus, fluorescent Pseudomonas and Biomass C were high at the lower reaches including Goryeong, which showed relatively much nutrient contents of organic matter, total N and phosphorous etc.

• Journal of Environmental Science International
• /
• v.22 no.7
• /
• pp.787-799
• /
• 2013

The aim of this study was to investigate the accumulation of metallic elements and the control effect of marine pollution caused by ocean dumping in the sediments at a waste disposal area in the Yellow Sea. In July 2009, concentrations of organic matter and metallic elements (Al, Fe, As, Cd, Cr, Co, Hg, Ni, Mn, Pb, and Zn) were measured in surface sediments at the site. The ignition loss (IL) in the surface sediments showed a mean value of 15.4%, about 1.5 times higher than the mean value of the sediments in the coastal areas of Korea. The chemical oxygen demand (COD) at some disposal sites exceeded 20 mg $O_2/g{\cdot}dry$, which signifies the initial concentration of marine sediment pollutants in Japan. The disposal sites contain higher concentrations of Cr, Cu and Zn than the sediments of bays and estuaries that might be contaminated. The magnitude of both metal enrichment factors (EF) and adverse biological effects suggest that pollution with Cr and Ni occurred due to the dumping of waste in the study area. In addition, the geoaccumulation index (Igeo) showed that the surface sediments were moderately contaminated. By the mid-2000s, when the amount of waste dumped at this site was the highest, the concentration of metallic elements was higher than ever recorded. On the other hand, in 2008-09, the need for environmental management was relatively low compare with the peak. As a result, the quality of marine sediment has been enhanced, considering the effect of waste reduction and natural dilution in the disposal area.

• Economic and Environmental Geology
• /
• v.32 no.6
• /
• pp.611-631
• /
• 1999

Enviromental geochemisty and heary metal contamination at the Kongjueil mine creek were underaken on the basis of physicohemical properties and mineralogy for various kinds of water (surface, mine and ground water),soil, precipitate and sediment collected of April and December in 1998. Hydrgeochemical composition of the water samples are characterized by relatively significant enricant of Ca+Na, alkiali ions $NO_3$ and Cl inground and surfore water, wheras the mine waters are relatively eneripheral water of the mining creek have the characteristics of the (Ca+Mg)-$(HCO_3+SO_4)$type. The pH of the mine water is high acidity (3.24)and high EC (613$\mu$S/cm)compared with those of surface and ground water. The range of $\delta$D and $\delta^{18}O$ values (relative to SMOW) in the waters are shpwn in -50.2 to -61.6% and -7.0 to -8.6$\textperthousand$(d value=5.8 to 8.7). Using computer program, saturation index of albite, calcite, dolomite in mine water are nearly saturated. The gibbiste, kaolinite and smectite are superaturated in the surface and ground water, respectively. Calculated water-mineral reaction and stabilities suggest that weathing of silicate minerals may be stable kaolinite owing to the continuous water-rock reaction. Geochemical modeling showed that mostly toxic heavy metals may exist larfely in the from of metal-sulfate $(MSO_4\;^2)$and free metal $(M^{2+})$ in nmine water. These metals in the ground and surface water could be formed of $CO_3$ and OH complex ions. The average enrichment indices of water samples are 2.72 of the groundwater, 2.26 of the surface water and 14.15 of the acid mine water, normalizing by surface water composition at the non-mining creek, repectively. Characteristics of some major, minor and rate earth elements (Al/Na, K/Na, V/Ni, Cr/V, Ni/Co, La/Ce, Th/Yb, $La_N/Yb_N$, Co/Th, La/Sc and Sc/Th) in soil and sediment are revealed a narrow range and homogeneous compositions may be explained by acidic to intermediate igneous rocks. And these suggested that sediment source of host granitic gneiss colud be due to rocks of high grade metamorphism originated by sedimentary rocks. Maximum concentrations of environmentally toxic elements in sediment and soil are Fe=53.80 wt.% As=660, Cd=4, Cr=175, Cu=158, Mn=1010, Pb=2933, Sb=4 and Zn=3740 ppm, and extremely high concentrations are found are found in the subsurface soil near the ore dump and precipitates. Normalizing by composition of host granitic gneiss, the average enerichment indices are 3.72 of the sediments, 3.48 of the soils, 10.40 of the precipitates of acid mine drainage and 6.25 of the soils near the main adit. The level of enerichment was very severe in mining drainage sediments, while it was not so great in the soils. mineral composition of soil and sediment near the mining area were partly variable being composed of quartz, mica, feldspar, chlorite, vermiculite, bethierin and clay minerals. reddish variable being composed of quartz, mica, feldspar, chlorite, vermiculite, bethierin and clay minerals. Reddish brown precipitation mineral in the acid mine drainage identifies by schwertmanite. From the separated mineralgy, soil and sediment are composed of some pyrite, arsenopyite, chalcopyrite, sphalerite, galena, malachite, goethite and various kinds of hydroxied minerals.

• Ocean and Polar Research
• /
• v.26 no.2
• /
• pp.231-243
• /
• 2004

Sequential extraction was carried out on twenty two subsamples of three ferromanganese crusts from three seamounts (Lemkein, Lomilik, and Litakpooki) near the Marshall Islands in the western Pacific. The extraction was designed to fractionate Fe-Mn crust forming elements into low defined groups: (1) exchangeable and carbornate, (2) Mn-oxide, (3) Fe-oxyhyd.oxide, and (4) residual fraction. X-ray diffraction result shows that target material were well removed by each extraction step except for CFA in phosphatized crusts generation. According to chemical analysis of each leachate, most of elements in the Fe-Mn crusts are bound with two major phases. Mn, Ba, Co, Ni, Zn, (Fe, Sr, Cu, and V) are strongly bounded with Mn-oxide $({\delta}-MnO_2)$ phase, whereas Fe, Ti, Zr, Mo, Pb, Al, Cu,(V, P, and Zn) show chemical affinity with Fe-oxyhydroxide phase. This result indicates that significant amount of Al, Ti, and Zr can not be explained by detrital origin. Ca, Mg, K, and Sr mainly occur as exchangeable elements and/or carbonate phase. Outermost layer 1 and inner layer 2 which are both young crusts generations are similar in chemical speciations of elements. However, some of Fe-oxyhydroxide bounded elements (Pb, Y, Mo, Ba, Al, and V) in phosphatized innermost layer 3 are released during phosphatization and incorporated into phosphate (Pb, Y, Mo, and Ba) or Mn-oxide phase (Al and V). Our sequential extraction results reveal that chemical speciations of elements in the hydrogenetic crusts are more or less different from interelemental relationship calculated by statistical method based on bulk chemistry.

• Economic and Environmental Geology
• /
• v.12 no.2
• /
• pp.79-93
• /
• 1979

Twenty five samples of the scheelite-powellite series from twelve Korean tungsten deposits of various geologic settings were studied mineralogically and geochemically. Variations in the trace-element contents of the scheelite minerals are considered in relation to geologic settings and mineralogic properties. Scheelites from ore deposits developed in similar geologic settings and under similar physicochemical conditions are characterized by specific combinations of trace elements.

• Journal of Ginseng Research
• /
• v.47 no.3
• /
• pp.448-457
• /
• 2023

Background: Alzheimer's disease (AD) is a common form of dementia, and impaired mitophagy is a hallmark of AD. Mitophagy is mitochondrial-specific autophagy. Ginsenosides from Ginseng involve in autophagy in cancer. Ginsenoside Rg1 (Rg1 hereafter), a single compound of Ginseng, has neuroprotective effects on AD. However, few studies have reported whether Rg1 can ameliorate AD pathology by regulating mitophagy. Methods: Human SH-SY5Y cell and a 5XFAD mouse model were used to investigate the effects of Rg1. Rg1 (1µM) was added to β-amyloid oligomer (AβO)-induced or APPswe-overexpressed cell models for 24 hours. 5XFAD mouse models were intraperitoneally injected with Rg1 (10 mg/kg/d) for 30 days. Expression levels of mitophagy-related markers were analyzed by western blot and immunofluorescent staining. Cognitive function was assessed by Morris water maze. Mitophagic events were observed using transmission electron microscopy, western blot, and immunofluorescent staining from mouse hippocampus. The activation of the PINK1/Parkin pathway was examined using an immunoprecipitation assay. Results: Rg1 could restore mitophagy and ameliorate memory deficits in the AD cellular and/or mouse model through the PINK1-Parkin pathway. Moreover, Rg1 might induce microglial phagocytosis to reduce β-amyloid (Aβ) deposits in the hippocampus of AD mice. Conclusion: Our studies demonstrate the neuroprotective mechanism of ginsenoside Rg1 in AD models. Rg1 induces PINK-Parkin mediated mitophagy and ameliorates memory deficits in 5XFAD mouse models.