• 한국대기환경학회지
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• 제8권1호
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• pp.20-28
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• 1992

The x-ray fluorescence(XRF) is one of the most convenient and widely used techniques for analyzing trace elements in ambient particulate matters. The objects of the study were to estimate the optimum exposure time using the XRF, to investigate the distributions of heavy metal levels in particulate matters, and finally to study seasonal variation for the concentrations of total suspended particulate matters(TSP) and size fractionated particulate matters. The suspended particulate matters had been collected by a cascade impactor having 9 size fragnated stages for 3 years(Dec. 1988 to Nov. 1991) in Kyung Hee University-Suwon Campus. The particulate matters were then collected on each stage by membrane filters. The weight concentrations were determined by the XRF system. Thus, seasonal variations and relationship between concentration and particle size could be investigated. Resulting distribution was bimodal with the coarse and the fine particle groups minimum occurring around 2.1 to 3.3 $\mu$m as an aerodynamic diameter. To determine optimum exposure time of the XRF for various trace inorganic elements, membrane filters and the NIST standard filters were extensively studied. Using a statistical technique, optimum exposure time was estimated for each trace element and overall elements. The time was then determined as 20 seconds for the XRF system. The concentration of TSP was 123.9$\mum/m^3$ on an arithmatic average. The levels of each inorganic metal were Si 2420.0ng/$m^3$, Fe 977.1ng/$m^3$, and so on. The Pb. Zn, and Cu abounded in the fine mode group, while Ca, Fe, Si, Al, and K in the coarse group. Marked seasonal variation of TSP and metal concentrations was observed. The concentration of heavy metals in the fine mode was highest in winter : on the other hand, that in the coarse mode was highest in spring.

• 비파괴검사학회지
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• 제23권1호
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• pp.14-20
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• 2003

고온$(500^{\circ}C)$ 환경에서 접촉식 탐상이 가능한 초음파 탐촉자를 개발하고 평가하였다. 고온용 탐촉자는 Curie 온도가 $600^{\circ}C$ 이상인 bismuth titanate 계열의 압전세라믹 소자, 텅스텐 분말과 inorganic binder를 혼합한 후면재, 알루미나 튜브, 전면재, 하우징 등으로 구성되었다. 기본 공진주파수가 각각 1.04 및 2.08 MHz의 2 종류 탐촉자를 제작하였으며 각종 고온용 커플런트의 온도특성을 시험하였다. 개발된 고온용 탐촉자를 이용하여 강재 시편을 대상으로 시편에서의 초음파 반사신호를 측정한 결과 시편의 온도가 증가함에 따라 반사신호의 크기는 감소하였다. 고온에서 반복측정 실험결과 $500^{\circ}C$에서 연속적인 접촉식 초음파 탐상이 가능한 것으로 나타났다.

• 미생물학회지
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• 제5권2호
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• pp.61-68
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• 1967

In the process of the incorporation of orthophsphate into protein and other cell constituents, the role of inorganic polyphosphate and RNA-polyphosphate complex and the correlation between them were pursued by analyzing the contents of $^{32}P$ and total P in various fractions of Chlorella cells, which had been uniformly labeled with $^{32}P$ before the inoculation in a normal "cold" medium or P-free medium during the culture. The effects of ionizing radiation and various micronutritional-element deficiencies on the phosphate incorporation into, and biosynthesis of, protein and other introgenus compounds in the cells were also observed. When the uniformly $^{32}P$-labeled algae were grown in a normal "cold" medium the contents of $^{32}$ P in the fractions of protein, DNA and RNA-polyphosphate complex increased, but those in the fraction of acid-insoluble polyphosphate decreased. On the other hand, amount of $^{32}P$in the fraction of RNA was almost unchanged in spite of rapid increase of the total P. In the growing period of $^{32}P$-labeled algae in a P-free medium, amounts of $^{32}P$ in the fractions of DNA, protein and lipid increased, while those in the fractions of RNA-polyphosphate and inorganic polyphosphates decreased. When the algal cells were irradiated with about 70, 000r of gamma-rays before the inoculation in the medium, amounts of phosphate in the fractions of DNA, RNA, nucleotides and protein decreased during the culture, compared with those of the control. However, the phosphate content in the fraction of acid-insoluble polyphosphate of the irradiated cells increased than those of the control. In the growing period of the algae in a Mo-free, medium, amounts of acid-soluble total phosphate and nucleotides of the cells increased, while the amounts of residual protein and RNA decresed compared with those of the normal cells. Amounts of alkali-labile protein and phospholipid of the cells grown in a B-free medium decreased, whereas amount of phosphate in acid-soluble fraction increased compared with the control. In general, the contents of protein and RNA in each microelement deficient cells decreased more or less, compared with those in the normal cells.in the normal cells.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제22권2호
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• pp.181-188
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• 2019

Purpose: Inadequate calorie intake is one of the most important causes of nonorganic failure to thrive (NOFTT) and is thought to lead to multiple micronutrient deficiencies. However, there have been few studies on NOFTT and micronutrients. The aim of this study was to evaluate the micronutrient status of children with NOFTT. Methods: We conducted a retrospective cohort study in 161 children (106 with NOFTT and 55 health controls) at a single institution. Data on weight for age, height for age, body mass index, and biochemical parameters, indicating the children's nutritional and micronutrient status were reviewed via electronic medical records, and the two groups were compared. Results: Except inorganic phosphate levels, no statistically significant differences were seen in the laboratory findings indicating the children's nutritional and micronutrient status; notably, the inorganic phosphate levels were within the normal range in both groups. We then compared the severe NOFTT (weight for age below the first percentile) and control groups; however, no statistically significant differences were seen for any of the measured parameters. Conclusion: Most children with NOFTT in this study had normal micronutrient levels and other laboratory findings. Therefore, element deficiencies should not be considered a natural consequence of NOFTT or in healthy children. Close monitoring and additional evaluations are needed.

• 한국수산과학회지
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• 제56권4호
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• pp.401-410
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• 2023

This study examined the characteristics of eel Anguilla japonica sperm using the CASA (computer-assisted sperm analysis) system and attempted to provide the composition for artificial seminal plasma by regulating of inorganic elements. Sperm samples were first divided into four groups based on motility and progressive motility: (A) 0-10%, (B) 10-40%, (C) 40-70%, and (D) 70-100%. For observing sperm velocity variations, VCL, which is curve motion velocity, showed the highest values in all groups. The directional factor, beat cross frequency, was lower in higher activity groups, showing an opposite correlation with sperm activity. The head sizes of spermatozoa in higher activity groups were significantly larger than those in lower activity groups. The Na⁺ and K⁺ ions were important in the inorganic composition of seminal plasma in this species. Furthermore, regulating the composition in artificial seminal plasma improved the formula compared to the existing element, exhibiting 120 mM Na and 30 mM K when the sperm was conserved for a long time and 120 mM NA and 40 mM K when the sperm was conserved for a short time.

• 한국환경농학회지
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• 제32권2호
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• pp.166-170
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• 2013

단감의 품질을 높이기 위한 다양한 칼륨 시비방법이 감 재배 농업인들에 의해 시도되어 왔다. 본 시험은 칼륨 시비량이 단감나무의 부위별 무기원소 농도와 과실 품질에 미치는 영향을 구명하기 위해 수행되었다. 50 L 용기에서 재배한 6년생 '부유' 감나무에 7월부터 9월까지 3-4일 간격으로 염화칼륨을 사용하여 주당 K를 0(무시비구), 12, 25, 37, 66 g씩 관주하였는데, 무시비구는 시험 전 2년간도 K 비료를 공급하지 않았다. 11월에 잎, 과실, 신초 시료를 채취하여 조사하였다. 잎과 신초의 K 농도는 시비량 증가로 높아졌으며, 잎에서 변화가 특히 뚜렷하여 무시비구에서 0.49%였으나 37 g과 66 g 시비구에서 각각 3.09%과 3.11%로 높아졌다. 과실의 K 농도는 무시비구에서 현저히 낮았고 12 g 이상의 시비구들 간에는 차이가 없었다. 무시비구의 나무는 6월부터 가장자리부터 잎맥이 검게 괴사하는 잎들이 나타났고 8월에는 일부 잎이 가장자리부터 말라서 말리기도 하였다. 과실 특성에 미치는 K 시비량의 가장 큰 효과는 과중에서 나타났는데, 무시비구에서 150 g이었으나 12 g 시비구에서 181g, 37 g 시비구에서는 203 g, 66 g 시비구에서는 206 g으로 증가하였다. 과실의 경도, 당도는 K 시비량에 따른 유의적인 변화가 없었으며 무시비구는 적색도가 특이하게 높았다. 본 연구결과로 K 시비량에 대한 수체 부위별 반응이 다르며, K 시비량은 품질 요소 중 과실 크기에 주로 영향을 주는 것을 알 수 있었다.

• 한국응용과학기술학회지
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• 제35권3호
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• pp.816-825
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• 2018

액화석유가스(Liquefied Petroleum Gas)를 연료(Fuel)로 하는 차량의 실제 운행단계에서 시동 꺼짐 현상 등이 발생한다는 소비자 민원이 접수 된 바 있으며, 최근 유통과정에서 녹 등의 이물질로 인한 소비자 피해 가능성이 제기되어 LPG 잔류물질(Residue) 항목에 대한 관리 필요성이 대두되었다. 본 연구에서는 LPG 국내생산 및 수입사 제품과 실제로 유통되고 있는 LPG의 잔류물질 특성을 연구하였다. LPG 잔류물질을 GC-MS를 사용하여 정성분석을 하였고, ICP-OES를 이용하여 무기물 성분을 분석하였다. GC-MS 분석결과 고무 제조공정을 용이하게 하기 위해 고무에 소량 배합하는 가소제(Plasticizer) 등이 분석되었다. 또한 ICP-OES를 이용한 무기물 분석결과 주로 LPG 생산 시 사용되는 소포제 등에서 유래된 것으로 추정되는 Si와 충전시설 등에 사용되는 그리스 첨가제 성분 등으로 추정되는 P와 Zn도 일부 검출되었다. 본 연구에서 분석된 LPG 잔류물질에 대해서는 녹 등을 유발할 수 있는 성분이 검출되지 않았지만 가소제 및 그리스 첨가제 성분이 LPG 연료계통에 영향을 줄 수 있으므로 적정품질의 고무류 사용과 저비점 그리스 첨가제 사용 확대가 필요할 것으로 보인다.

• 농업과학연구
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• 제42권3호
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• pp.191-199
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• 2015

We conducted this research to observe the changes of surface morphology and composition of clay minerals influenced by various concentrations of fluoric acid. Hydrofluoric acid (HA), a solution of hydrogen fluoride (HF) in water, is a colourless solution that is highly corrosive, capable of dissolving many materials, especially oxides. To do this, we treated several concentrations of HA on the ground soil samples collected from the agricultural experimental station located at Chungnam National University to observe the influence of fluoric acid on the changes of surface structures and elemental composition of clay particles. Generally, microscopic examination showed that the HA can not only attack an edge of clay particles but also start at any point where structural defects and weaknesses predisposed sites to acid. The orderly flake arrangement of clay minerals may reflect certain crystal symmetry elements. The ESEM-EDS results of element composition of clay particles influenced by HA indicated the changes of structures of clay minerals. It is also clear from the formation of etch figures and element composition of clay particles that the product layer at least partially dissolved or disintegrated in the presence of acid. Conclusively, the clay structures can be strongly influenced by concentrations of HA, resulting in changes of physical and chemical properties that can determine the behavior of solute transport as well as mobility of ions in soils.

• 한국세라믹학회지
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• 제56권2호
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• pp.111-129
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• 2019

Recently, all-solid-state batteries (ASSBs) have attracted increasing interest owing to their higher energy density and safety. As the core material of ASSBs, the characteristics of the solid electrolyte largely determine the performance of the battery. Thus far, a variety of inorganic solid electrolytes have been studied, including the NASICON-type, LISICON-type, perovskite-type, garnet-type, glassy solid electrolyte, and so on. The garnet Li₇La₃Zr₂O₁₂ (LLZO) solid electrolyte is one of the most promising candidates because of its excellent comprehensively electrochemical performance. Both, experiments and theoretical calculations, show that cubic LLZO has high room-temperature ionic conductivity and good chemical stability while contacting with the lithium anode and most of the cathode materials. In this paper, the crystal structure, Li-ion transport mechanism, preparation method, and element doping of LLZO are introduced in detail based on the research progress in recent years. Then, the development prospects and challenges of LLZO as applied to ASSBs are discussed.

• 한국작물학회지
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• 제40권5호
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• pp.587-593
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• 1995

야생더덕과 재배더덕의 재배장소에 따른 생육특성, 품질 및 향기성분을 비교분석한 결과를 요약하면 다음과 같다. 1. 자생지의 기상환경은 재배지에 비해 기온이 4∼8 낮고 지온도 3 낮았으며 조도량은 재배지의 1.7% 정도였다. 2. 자생지 토양의 환경조건은 재배지 토양에 비하여 pH는 낮았으나 유기물함량은 3배 이상 높았다. 3. 야생더덕과 재배더덕의 염색체 수는 2n =16으로 같았고 자방수도 3개로 동일하였으나, 종자수는 재배더덕이 62개, 야생더덕이 132개로 야생더덕 이 2배 정도 많았다. 4. 야생더덕과 재배더덕의 생육은 재배지보다 자생지에서 저조하였으나 야생더덕은 재배지에서도 재배더덕에 비해 현저하게 떨어졌다. 5. 재배장소에 따른 더덕의 방향성분의 extract수율은 야생더덕은 재배지보다 자생지에서 높았으나 재배더덕은 재배장소에 따른 변화의 차이를 보이지 않았고 extract수율도 50% 정도 낮았다. 6. 재배지에 따른 주요 무기성분함량은 자생지보다 재배지에서 많았으며 야생더덕보다 재배더덕에서 많았다 7. 더덕의 재배장소에 따른 주요 방향성분의 변화는 dimethylbenzene, 3-ethyl-5-2- ( ethylbutyl ) -octadecane, benzaldehyde, 14, 14-dimethyl -hexadecanoate, methylhexadecenoate등이 재배더덕에서는 없는 향기성분이 야생더덕에서 검출되었으며 더덕의 향을 내는 성분은 단일성분이 작용하기 보다는 peak면적이 높게 나타난 성분들이 복합적으로 작용하여 향기를 내는 것으로 판단되었다.