• 한국대기환경학회지
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• 제18권4호
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• pp.317-325
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• 2002

An air pollution monitoring station has been operated at Tokchok Island since April 1999 to characterize the background atmosphere in the vicinity of the Yellow Sea. In this study, eight chemical species in PM$_{2.5}$ and three gaseous species were analyzed. A total of 53 samples were collected for the analysis of PM$_{2.5}$ and gaseous species from April, 1999 to April, 2001. The overall mean mass concentration of PM$_{2.5}$ was 20.8 $\mu\textrm{g}$/㎥ and the eight soluble ionic species accounted for about 46.8% of PM$_{2.5}$ mass. Approximately 80% of samples appeared to experience the chloride loss effect. Air pollutant sources of PM$_{2.5}$ measured at Tokchok Island were qualitatively identified by the principal component analysis. It was found that five principal components are secondary aerosol, soil, incineration, phase change of nitrate, and ocean.and ocean.

• 한국식품저장유통학회지
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• 제7권1호
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• pp.19-22
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• 2000

This study was carried out investigate the storability of onions on calcium spraying, after cutting foliage, 6 different treatemnt , the dilution spraying of calcium nitrate 9 3%, 6%) , calcium carbonate(3%, 6%), dust scattering and the controls were evaluated for rotting, sprouting, healthy bulb and total weight loss ratio during storage. Rotting ratio on the dilution spraying of 6% calcium carbonate was lower than that of the control after 4 months storage by 16.7%. Sprouting and total weight loss were decreased in the dilution spraying of 6% calcium carbonate.

• 한국재료학회지
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• 제24권4호
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• pp.214-220
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• 2014

In this research, a precipitation method was used to synthesize ${\beta}-Ga_2O_3$ powders with various particle morphologies and sizes under varying precipitation conditions, such as gallium nitrate concentration, pH, and aging temperature, using ammonium hydroxide and ammonium carbonate as precipitants. The obtained powders were characterized in detail by XRD, SEM, FT-IR, and TG-DSC. From the TG-DSC result, GaOOH phase was transformed to ${\beta}-Ga_2O_3$ at around $742^{\circ}C$, and weight loss percent was about 14 % when $NH_4OH$ was used as a precipitant. Also, ${\beta}-Ga_2O_3$ formed at $749^{\circ}C$ and weight loss percent was about 15 % when $(NH)_2CO_3$ was used as a precipitant. XRD results showed that the obtained $Ga_2O_3$ had pure monoclinic phase in both cases. When $(NH)_2CO_3$ was used as a precipitant, the particle shape changed and became irregular. The range of particle size was about $500nm-4{\mu}m$ based on various concentrations of gallium nitrate solution with $NH_4OH$. The particle size was increased from $1-2{\mu}m$ to $3-4{\mu}m$ and particle shape was changed from spherical to bar type by increasing aging temperature over $80^{\circ}C$.

• 한국연초학회지
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• 제7권1호
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• pp.7-13
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• 1985

Effect of the two PVY strains(PVY-VB and PVY-VN) on yield and chemical constituents of tobacco plants was determined in roar. NC2326 and Burley 21. The virus was inoculated 6 and 8 weeks after transplanting, respectively. The strains and time of inoculation were most critical factors for yield reduction. The greatest reduction was caused by the necrotic strain (PVY-VN) inoculated 6 weeks after transplanting, accounting for the loss of 40% in var. NC2326 and of 45% in var.. Burley21. When inoculated 8 weeks after transplanting with the necrotic strain, only 17% reduction was recorded in roar. Burley21, but no reduction occurred in roar. NC2326. Generally less reduction was caused by the PVY-VB strain, ranging 12-16% depending on the time of inoculation and/or variety. Compared to healthy tobacco, PVY infected tobacco contained higher concentrations of total nitrogen, protein nitrogen, nitrate nitrogen, and lower total sugar in cured leaf of roar. NC2326. Total alkaloid, P, Mg, Ca, and K levels were not altered. In var. Burley21, protein nitrogen and nitrate nitrogen increased, but other chemical components were not changed. Necrotic strain-infected tobacco with a severe symptom had higher nitrogen than did mild strain-infected tobacco.

• 한국재료학회지
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• 제30권3호
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• pp.131-135
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• 2020

Silver nanowire (AgNW) networks have been adopted as a front electrode in Cu(In,Ga)Se2 (CIGS) thin film solar cells due to their low cost and compatibility with the solution process. When an AgNW network is applied to a CIGS thin film solar cell, reflection loss can increase because the CdS layer, with a relatively high refractive index (n ~ 2.5 at 550 nm), is exposed to air. To resolve the issue, we apply solution-processed ZnO nanorods to the AgNW network as an anti-reflective coating. To obtain high performance of the optical and electrical properties of the ZnO nanorod and AgNW network composite, we optimize the process parameters - the spin coating of AgNWs and the concentration of zinc nitrate and hexamethylene tetramine (HMT - to fabricate ZnO nanorods. We verify that 10 mM of zinc nitrate and HMT show the lowest reflectance and 10% cell efficiency increase when applied to CIGS thin film solar cells.

• 한국의류학회지
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• 제32권2호
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• pp.319-327
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• 2008

The purpose of this study is to propose the development of high quality electromagnetic wave shielding fabrics. Silver nitrate is used for polyester fabric as an electromagnetic wave shielding material. The effects of activators and electroless silver plating condition on the evenness and adhesion of silver to fabrics, are observed through the SEM micrographs. Surface morphology and wash-ability are measured using SEM. The results are as follows: The optimum weight loss by alkaline hydrolysis of polyester fabrics is about 20%. The optimum concentration of $SnCl_2$ and $PdCl_2$in catalyst reaction using $PdCl_2$ as an activator is 2.5g/L and 0.5g/L, respectively. The optimum concentration of dextrose to improve adhesion between the silver plating and fabrics is 45g/L. The optimum concentration of silver nitrate in the catalyst reaction, using $PdCl_2$ as an activator is 56g/L, respectively. The optimum plating temperature and time are $15^{\circ}C$ and 30minutes, respectively.

• 한국토양비료학회지
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• 제41권4호
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• pp.260-266
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• 2008

질산과 인산의 수직이동성에 대한 토양특성의 영향을 구명하고자 비가림 하우스에서 소형라이시메터(지름 300 mm, 토양깊이 450 mm) 시험을 수행하였다. 대상토양은 농경지 세 지점으로부터 표토 0~20cm를 채취한 후 이 토양의 풍건세토분획을 이용하여 수행하였다: mesic family of Typic Dystrudepts (토양 A, 사양토, 유기물함량 1.4%); mixed, mesic family of Typic Udifluvents (토양 B, 양토, 유기물함량 2.6%); 시설재배토양(토양 C, 사양토, 유기물함량 5.6%). 2주 동안 안정화시킨 토양의 표면에 질소와 인을 $150kg\;urea-N\;ha^{-1}$ 과 $100kg\;KH_2PO_4-P_2O_5\;ha^{-1}$ 만큼 처리하고, 65일 동안 7번 관수(총관수량 213 mm, 약 1 pore volume)하며 주기적으로 깊이 10, 20, 30 cm의 토양용액과 용탈액을 채취하여 질산과 인산농도를 분석하였다. 총 용탈액량은 토양 C > 토양 A > 토양 B 순으로 질산 용탈량, 토양 B > 토양 A > 토양 C 과 역의 관계를 가졌다. 토양 A와 B에서는 요소처리 후 깊이 10 cm에서 토양용액 중 질산 농도 증가가 뚜렷이 나타난 반면, 토양 C에서는 나타나지 않았다. 토양 B의 높은 질산이동성은 상대적으로 높은 점토함량으로 음전하를 띤 교질의 음이온배척과 느린 수분흐름으로 물의 머무름시간이 길어 토양매트릭스 질산의 추출을 촉진하기 때문으로 볼 수 있었다. 반면 토양 C는 질산의 이동성이 낮게 나타났다. 이는 유기물 함량이 높아 생기는 발수성으로 선택류와 질산의 미생물 부동화 때문으로 추정할 수 있었다. 인산용탈은 질산과 달리 인포화도가 가장 높은 토양 C에서만 검출되었다. 토양용액 중 인산농도는 인포화도의 순서와 동일하게 토양 C > 토양 B의 순서였고 토양 A에서는 검출되지 않았다. 따라서 인산의 이동성은 인포화도에 의해 크게 영향을 받으며, 일정 수준으로 축적될 때 까지는 용탈손실은 나타나지 않는다고 판단할 수 있었다.

• 한국콘텐츠학회논문지
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• 제12권1호
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• pp.353-360
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• 2012

본 연구에서는 현재 자가 미백용으로 많이 사용하고 있는 15% carbamide peroxide(CP)에 potassium nitrate와 fluoride(PF)가 함유된 제품과 미 함유된 제품을 사용하여 색과 표면미세경도를 측정하였다. 건전한 소구치 30개를 이용하여 30개의 시편을 제작하였고, 각 각 10개씩 3군으로 분류하였다. 1군은 대조군 (Distilled water), 2군은 15% CP, 3군은 15% CP(3% potassium nitrate and 0.11% fluoride 함유)이다. 치아미백은 14일 동안 하루에 6시간 미백하고 이후 시간은 증류수에 보관하였다. 색 측정은 미백 전과 14일에 측정하였고, 표면미세경도는 미백 전, 7일, 14일에 측정하여 다음과 같은 결과를 얻었다. 색변화를 본 결과 미백하지 않는 대조군 1군과 미백제가 함유된 2군과 3군에는 통계적으로 유의한 차이가 보였고(p<0.05), 2군과 3군 사이에는 통계적으로 유의한 차이를 나타내지 않았다(p>0.05). 표면미세경도 변화를 비교해보면 시간이 경과함에 따라 대조군을 제외하고 2군과 3군에서는 미백 전 경도 값에 비해서 미백 후 유의하게 경도의 감소를 보였고(p<0.05), 특히 미백 7일째 경도 값의 차이가 미백 후 14일보다 컸다. 미세경도 감소율을 보면 대조군인 1군은 7일과 14일에 각 각 1.7과 0.8로 차이가 거의 없으나 2군은 21.9,와 3.5이고, 3군은 16.7과 1.4로 미백 7일째에서 유의하게 감소했고(p<0.05), PF가 미 함유된 2군의 7일째 미세경도 감소율이 가장 컸다. 이상의 결과를 종합해 보면, PF는 치아미백에 부정적 영향을 주지 않으며, 미세경도 변화에서는 PF가 함유된 미백제에서 경도 감소율이 적었다. 따라서 PF가 함유된 치아미백제는 미백효과와 함께 치아법랑질의 경도 감소를 줄일 수 있다.

• Journal of Applied Biological Chemistry
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• 제43권4호
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• pp.258-263
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• 2000

The study was carried out to investigate the nutrient losses at a paddy field located at the southwest of central Korea from May 1, 1997 to April 30, 1998. The studying area was 10 ha. The amounts of nutrients loaded by runoff water were measured as follows. The total-N was 1,031 and $61kg\;10ha^{-1}$ during the irrigation and non-irrigation periods, respectively. The total amount of N from both periods was $1,092kg\;10ha^{-1}\;yr^{-1}$. The total-P was 23 and $2kg\;10ha^{-1}$ during the irrigation and non-irrigation periods, respectively. The total amount of P from both periods was $25kg\;10ha^{-1}\;yr^{-1}$. For percolationloss, the losses of total-N, ammonia-N, nitrate-N, and total-P were 167,30,122, and $3kg\;10ha^{-1}$, respectively. The respective loss ratios of N and P by runoff water were 55.2 and 11.9%, while the loss ratios of N and P by percolationwere 8.4 and 1.4%.

• Asian Journal of Atmospheric Environment
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• 제3권1호
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• pp.27-41
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• 2009

Internally mixed states of submicron particles during transport from the Asian continent to the Pacific Ocean were analyzed using a single-particle time-offlight mass spectrometer. The observation was conducted at Tsukuba in Japan in the spring of 2005 in order to investigate springtime transport of particles from the continent. The sum of ion intensities of sulfate (${HSO_4}^-$) detected in particles originating from the continental air masses counted for 75% of that in all particles during the observation. By analyzing correlations among compounds, origins and internally mixed states of compounds were estimated. It was found that nitrate was mixed with sulfate-rich particles as the air mass approached Japan. It was confirmed that Asian mineral dust particles played significant roles for transport of continental sulfate to Japan. As a result of analysis on internal mixing of chlorine and nitrate, it was implied that the chlorine loss in fine sea salt particles had already proceeded at Tsukuba. It was characteristic that fluoride ions were significantly detected, coal combustion in the Asian Continent can be an important source of fluorides detected in Japan through the westward transportation of fine particles including fluorides.