• Journal of the Korean Chemical Society
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• v.51 no.2
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• pp.178-185
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• 2007

Intermediate pentasil borosilicate zeolite-like materials have been crystallized by a novel method named steam-assisted conversion, which involves vapor-phase transport of water. Indeed, amorphous powders obtained by drying Na2O.SiO2.B2O3.TBA2O gels of various compositions using different boron sources are transformed into crystalline borosilicate zeolite belonging to pentasil family structure by contact with vapors of water under hydrothermal conditions. Using a variant of this method, a new material which has an intermediate structure of MFI/MEL in the ratio 90:10 was crystallized. The results show that steam and sufficiently high pH in the reacting hydrous solid are necessary for the crystallization to proceed. Characterization of the products shows some specific structural aspects which may have its unique catalytic properties. X-ray diffraction patterns of these microporous crystalline borosilicates are subjected to investigation, then, it is shown that the product structure has good crystallinity and is interpreted in terms of regular stacking of pentasil layers correlated by inversion centers (MFI structure) but interrupted by faults consisting of mirror-related layers (MEL structure). The products are also characterized by nitrogen adsorption at 77 K that shows higher microporous volume (0.160 cc/g) than that of pure MFI phase (0.119 cc/g). The obtained materials revealed high surface area (~600 m2/g). The infrared spectrum reveals the presence of an absorption band at 900.75 cm-1 indicating the incorporation of boron in tetrahedral sites in the silicate matrix of the crystalline phase.

• Applied Chemistry for Engineering
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• v.10 no.5
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• pp.754-760
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• 1999

The properties of the catalyst for a direct internal reforming type molten carbonate fuel cell were examined by ICP, BET, CHN, EDS, and $H_2$ chemisorption. Potassium and lithium, the components of carbonate electrolyte, were transported to the catalyst during the operation of fuel cell, and the amounts of the deposited alkali elements were reduced in the order of inlet, outlet, and the middle. From the direct correlation between the amount of alkali and the physical properties such as BET surface area and Ni dispersion, and from the observation of the lump of the alkali species on the poisoned catalyst, it was confirmed that the physical blocking of the catalyst by alkali deposition was the main reason for the deactivation. Although the amount of alkali species was greater at the inlet than at the oulet, the catalyst sampled from the outlet had lower activity. This was caused by the chemical interaction between the alkali species and the catalyst at the outlet where temperature was highest in the cell body, which was detected by FT-IR analyses.

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.31-39
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• 2007

Monitoring data of 48 agricultural irrigation reservoirs from 1999 to 2004 was analyzed for water quality characteristics including biochemical oxygen demand $(BOD_5)$, chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP), and chl-${\alpha}$. Land uses of the watersheds associated with these reservoirs were determined for residential, forest, upland, paddy and miscellaneous, and regressed against water quality characteristics. Correlation analysis showed that forest land use was negatively correlated with all the water quality characteristics implying it's beneficial effects in water quality perspectives. Other land uses including residential, upland, and paddy generally illustrated positive correlation with water quality characteristics, which indicates most human activities of the watershed could degrade water quality of the receiving water bodies. Paddy land use partially contributed to the water quality degradation in contrast to the previous studies. It might be attributed to the relatively clean water quality of the study area, where even slight pollutant loading could degrade sensitively water quality. Further investigation is recommended for the effect of proximity as well as land use portions on the water quality of receiving water body.

• Journal of Animal Environmental Science
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• v.14 no.3
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• pp.159-166
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• 2008

This research was carried out to test and analyze capacity of the long distance sprayer fan in large livestock farmhouses. Long distance sprayer was manufactured to be able to spray a lot of water, which was a solvent for agricultural chemicals and black dye with the maximum spraying distance of 140 m and the effective spraying distance of 100 m. The spraying quantity and the distance were measured the intensity values of images within A4 papers, which absorbed the agricultural chemicals by spraying by binary image processing. These A4 papers were fixed upon the height of 1 m from soil ground at regular 10 m interval. After the A4 papers were collected and analyzed the intensity values of gray level. Gray level was ranged from 0 to 255, where 0 was black and 255 was white. A4 paper was fallen down from the stick at 10 m distance, because there were too large amount of sprayed water with black dye. Also, the paper showed low gray level at distance 30 m because of dropping lots of black water. The intensity value of gray level was showed almost less than 200 on the A4 papers between the distance 20 m and 100 m, which meant equality of spraying quantity. Additionally, it was possible to spay agricultural chemicals of until 180 m. Throughout this research, long distance sprayer could apply for preventing hoof-and-mouth disease in large livestock farmhouses.

• Journal of Wetlands Research
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• v.13 no.3
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• pp.523-534
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• 2011

In this study, the particle size distribution and pollutants content of sediments collected from different sites in the coastal area of Chungnam province were analyzed. The sediment samples were collected from different parking lots near beaches, harbors, museum and bridges. The particle size distribution analysis showed that the particle is generally $106-500{\mu}m$ and the effective size $D_{10}$ ranges from 40 to $60{\mu}m$ while the $D_{50}$ and $D_{60}$ ranges from 200 to $810{\mu}m$ and 235 to $1005{\mu}m$, respectively. For particle size $D_{10}$, there was no significant difference in all sites. However, for $D_{50}$ and $D_{60}$, the range is large. Sediment analysis implicates that as the particle size decreases, the pollutant content increases. This is because smaller particles have higher specific surface area resulting to have more adsorption capacity. Particles from tires, emission gas from vehicles and dust particles belongs to smaller particles. For particle sizes less than $63{\mu}m$, the analysis showed that as the particles become coarser, the concentration of VS, $COD_{cr}$, TN, and TP is at least 2 to 14 times higher. Cu and Pb were detected in all sites and shows a higher concentration with smaller particle size. Cu concentration are almost the same for all sites but in the case of Pb, the sediments from Sinjindo has higher concentration of up to 2 to 3 times as compared to those collected from the other sites. In the Beach site as well as in the Seocheon Ocean Museum, Cd was contained only in fine particles. However, in Daechon Harbor and Sinjindo Bridge sites, Cd was detected in all the sediment particle size.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.258-258
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• 2013

최근 건조 제품의 양질화, 고급화 및 편의화가 요구되어 이를 충족시키기 위한 새로운 건조방법이 계속 개발 되어 왔다. 이러한 방법들 중에서 저온과 진공하에서 건조가 이루어지는 진공 동결 건조는 가장 완벽한 건조 방법으로 최근 실용화 되고 있다. 진공동결건조란 건조의 한 종류로 수분을 함유한 시료를 동결시킨 후 진공펌프를 이용하여 수증기압을 3중점 이하로 낮추어 얼음을 직접 증기로 만드는 승화의 원리에 의해서 얻어진다. 분무진공동결건조의 특징은 (1) 물리적구조의 보존성, (2) 화학적인 안정성, (3) 생물학적인 활동의 보존성, (4) 제품의 높은 복원성 및 재생성이다. 따라서 분무진공동결건조 기술은 크게 진공, 분무, 동결, 건조, 멸균 등과 같은 요소기술의 복합기술이라 할 수 있다. 분말을 제조하기 위해서 진공동결건조 후 분쇄하는 방법을 사용하나 본 방법에서는 정밀화학품 제조를 위해서 분무진공동결건조 방식을 사용한다. 이를 통하여 적당한 크기인 5~10 um의 입경 제조가 가능하고, 공기동력학적인 입경이 기존 방식에 비해 작아서 허파까지의 운반효율이 1.5~2배 우수하다. 화학, 의학 분야에서의 분무동결 건조는 주로 민감한 제품, 즉 생물학적 고유성의 손상 없이 물을 제거하는데 사용되어 영구적으로 저장 가능한 상태로 보관할 수 있으며 물의 첨가로 원상태로 복구할 수 있어서 매우 각광을 받고 있다. 의약용 냉동건조 제품은 항생물질, 박테리아, 혈청, 백신, 검사 약물, 단백질을 포함하는 생물공학 제품들, 세포, 섬유, 화학제품 등이 있으며 주로 vial 또는 ampule 상태로 건조가 이루어진다.본 연구에서는 원료를 $-194^{\circ}C$의 액체질소에 분무시켜 동결된 미립자를 형성한 후 진공 및 저온상태에서얼음의 승화(sublimation)에 기반한 1차 건조와 수증기 탈착(desorption)에 기초한 2차 건조 과정으로 구성된 분무진공동결건조기를 개발하였다. 분무동결 과정의 해석을 통해 2유체식 노즐을 통해 분무된 미세 입경의 액적이 액체 질소 표면까지 도달하는 회수률, 분무 노즐의 위치, 운전 조건 및 용기의 설계의 최적화를 수행하였다. 초기 액적속도, 분무노즐의 높이, 흡입구 추가에 따른 액적 유동 및 회수의 특성을 제시하였으며 이를 통한 분사시스템 고도화 가능성을 제시하였다. 구형의 미세 입자가 적층된 제품의 동결건조 공정의 해석은 흡착승화 모델(sorption sublimation model)을 기반으로 다음과 같은 열전달, 물질전달, 상변화 모델을 고려하여 유도되었다. 분무노즐 및 냉동/진공 배기계 시작품을 개발하여, 표면의 고다공도를 갖춘 입경 3~20 m 정도의 시료를 얻을 수 있으며, 동역학적 입경 5 m 충족함을 확인하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.603-608
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• 2018

Although the voltage-applied discharge method is most widely used in the semiconductor and display industries, periodic management costs are incurred because the method causes defects due to the absorption of ambient fine dust and causes emitter tip contamination due to the discharge. The emitter tip contamination problem is caused by the accumulation of fine particles in ambient air due to the corona discharge of the ionizer. Fuzzy ball generation accelerates the wear of the emitter tip and deteriorates the performance of the ionizer. Although a mechanical cleaning method using a manual brush or an automatic brush is effective for contaminant removal, it requires management of additional mechanical parts by the user. In some cases, contaminants accumulated in the emitter may be transferred to the wafer or product. In order to solve this problem, we developed an ionizer for a clean environment that can remove the pencil-type emitter tip and directly ionize the surrounding gas molecules using the tungsten wire located inside the ion tank. As a result of testing and certification by the Korea Institute of Machinery and Materials, the average concentration was $0.7572particles/ft^3$, the decay time was less than two seconds, and the ion valance was 7.6 V, which is satisfactory.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.3
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• pp.171-180
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• 2002

The temporal and spatial distributions of phosphorus have been investigated in the Gomso Bay, Korea. TP, PIP, TOP and DIP in sediment were found 548.8mg P kg$^{-1}$ , 426.1mg P kg$^{-1}$ , 122.6mg P kg$^{-1}$ , and 0.217mg P kg$^{-1}$ , respectively with a decreasing order of PIP>TOP>DIP. Any temporal or spatial trend has not been found on the distribution of TP in the sediment, except the high TP values near the mouth of Julpo-chun. We found seasonal patterns high TOP(28.90% of TP) and low TIP(71.10% of TP) in August, but low TOP(15.63% of TP) and high TIP(84.38% of TP) in November. There were three times higher DIP concentration in August than in November. Such case is probably not only due to the enhanced supply of DIP directly from the decomposition of organic matter from overlying water in summer, but also the released phosphate from the adsorbed particulate matter such as PIP under the low pH and Eh conditions at the subsurface layers of the sediment induced by the active microbial respiration of increased organic materials in summer. Primarily, the source of phosphorous from municipal sewage strongly influenced the early stage of the distribution of all the phosphorous in the Gomso tidal flat. Notwithstanding, through the processes of diagenesis in sediment, water temperature and organic contents probably functioned as the key parameters to control the temporal distributions of TOP, TIP and DIP in the Gomso tidal flat.

• Korean journal of applied entomology
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• v.34 no.3
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• pp.181-190
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• 1995

Malate dehydrogenase in the mosquito ovary after a blood meal, Aedes aegypti, was purified and characterized. MDH purification steps involved DEAE-Sepharose, S-Sepharose and Cibacron blue affinity chromatography. The purified MDH was 70,000 daltons in molecular weight and was a homodimer consisting of tow identical subunits. Optimal activity of purified MDH was obtained pH 9.0-9.2 in malate-oxaloacetate reaction and pH 9.8-10.2, in oxaloactate-malate reaction. With obtained pH 9.0-92 in malate-oxaloacetate reaction and pH 9.8-10.2, in oxaloactate-malate reaction. With malate as substrate, purified mitochondrial MDH (1.28$\times$${10}^{-4}$ M) had lower Km value than cytoplasmic MDH (8.92x${10}^{-3}$ M). MDH activity was inhibited by citrate, $\alpha$-ketoglutarate, and ATP. Inhibition of MDH activity by ATP and citrate was less in malate-oxaloacetate reaction and in oxaloacetate-malate reaction. MDH activity was completely inhibited by ATP in oxaloacetate-malate reaction and not inhibited by citrate in malate-oxaloacetate reaction. Temporal activity change of MDH is similar to that of isocitrate dehydrogenase in the ovary after blood feeding; their activities in the ovary began to rise at 18 hours after a blood meal, and reached at the maximal level at 48 hours.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.141-147
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• 1996

1979년 3월 Three Mile Island 2 (TMI-2) 발전소에서 사고가 발생했을 때 원자로용기내에 생성된 수소기체로 인하여 운전원은 원자로용기의 수위를 정확히 측정할 수 없었으며, 이로 인하여 사고상태를 신속히 파악하지 못하였다. TMI 사고이후 미국 원자력규제위원회 NRC는 이 같은 문제점을 해결하고자 미국내 모든 원전에서 사고 또는 비정상 조건이 발생할 경우에 원자로 용기 수위에 대하여 운전원이 신뢰성을 갖을 수 있는 후속조치를 수행토록 요구하였다. 또한 미국의 대표적인 전력연구소인 EFRI에서는 개량형 경수로 (Advanced Light Water Reactor : ALWR) 설계 요건으로 이러한 설계가 반영되도록 요건화 하였다.［1］. 본 논문에서는 2,825 MWt급 한국형 표준원전을 대상으로 EPRI에서 요구한 설계요건에 따라 TMI 2 발전소에서와 같은 사고로 인하여 수소기체가 발생했을 경우와 발전소가 비정상 상태로 인하여 증기가 발생했을 경우에, 이를 신속히 제거하여 운전원이 원자로용기의 수위를 정확히 감지할 수 있도록 하는 설계 방안을 검토하였다. 따라서, 설계방안으로 원자로용기에 모인 증기 또는 수소기체를 계통중 가장 높은 위치에 있으며, 계통구성 기기중 유일하게 2상을 유지하고 있는 가압기로 배출시키고자 두 기기간에 연결관을 설치하는 방안에 대해서 분석하였다. 원자로용기 상부해드와 가압기를 연결하는 방안은 여러가지가 있으나, 검토한 결과 한국형 표준원전에서는 연결관을 가압기 상부해드보다 4m 높게하여 원자로용기 상부해드와 연결하는 방안이 EPRI의 설계요건을 만족하면서 기존설계에 영향을 가장 적게 미치는 적합한 설계방안으로 분석되었다.크다는 단점이 있다.TEX>$_2$O$_3$ 흡착제 제조시 TiO$_2$ 함량에 따른 Co$^{2＋}$ 흡착량과 25$0^{\circ}C$의 고온에서 ZrO$_2$와 $Al_2$O$_3$의 표면에 생성된 코발트 화합물을 XPS와 EPMA로 부터 확인하였다.인을 명시적으로 설명할 수 있다. 둘째, 오류의 시발점을 정확히 포착하여 동기가 분명한 수정대책을 강구할 수 있다. 셋째, 음운 과 정의 분석 모델은 새로운 언어 학습시에 관련된 언어 상호간의 구조적 마찰을 설명해 줄 수 있다. 넷째, 불규칙적이며 종잡기 힘들고 단편적인 것으로만 보이던 중간언어도 일정한 체계 속에서 변화한다는 사실을 알 수 있다. 다섯째, 종전의 오류 분석에서는 지나치게 모국어의 영향만 강조하고 다른 요인들에 대해서는 다분히 추상적인 언급으로 끝났지만 이 분석을 통 해서 배경어, 목표어, 특히 중간규칙의 역할이 괄목할 만한 것임을 가시적으로 관찰할 수 있 다. 이와 같은 오류분석 방법은 학습자의 모국어 및 관련 외국어의 음운규칙만 알면 어느 학습대상 외국어에라도 적용할 수 있는 보편성을 지니는 것으로 사료된다.없다. 그렇다면 겹의문사를 [-wh]의리를 지 닌 의문사의 병렬로 분석할 수 없다. 예를 들어 누구누구를 [주구-이-ν가] [누구누구-이- ν가]로부터 생성되었다고 볼 수 없다. 그러므로 [-wh] 겹의문사는 복수 의미를 지닐 수 없 다. 그러면 단수 의미는 어떻게 생성되는가\ulcorner 본 논문에서는 표면적 형태에도 불구하고