• 대한수학회논문집
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• 제37권3호
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• pp.681-692
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• 2022

Special functions and Geometric function theory are close related to each other due to the surprise use of hypergeometric function in the solution of the Bieberbach conjecture. The purpose of this paper is to provide a set of sufficient conditions under which the normalized four parametric Wright function has lower bounds for the ratios to its partial sums and as well as for their derivatives. The sufficient conditions are also obtained by using Alexander transform. The results of this paper are generalized and also improved the work of M. Din et al. [15]. Some examples are also discussed for the sake of better understanding of this article.

• Elastomers and Composites
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• 제58권2호
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• pp.87-94
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• 2023

Abrasion tests of an SBR compound were conducted using four different types of abrasion testers (cut and chip, Lambourn, DIN, and LAT100). The abrasion test results were analyzed in terms of size distributions and morphologies of the wear particles. Most wear particles were larger than 1000 ㎛. The wear particle size distributions tended to decrease as the particle size decreased. Except for the Lambourn abrasion test, the wear particles smaller than 212 ㎛ were rarely generated by the other three abrasion tests, implying that small wear particles were produced through friction by introducing talc powder. Shapes of the wear particles varied depending on the abrasion testers. The wear particles generated from the Lambourn abrasion tester had stick-like shapes. The cut and chip abrasion test showed a clear abrasion pattern, but the DIN abrasion test did not show any specific abrasion pattern. The Lambourn and LAT100 abrasion tests showed irregular abrasion patterns.

• 대한자원환경지질학회:학술대회논문집
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• 대한자원환경지질학회 2001년도 춘계 공동학술발표회
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• pp.157-159
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• 2001

• 전기기술인
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• 제245권1호
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• pp.26-29
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• 2003

유럽은 국가마다 KS와 같은 공업표준이 있다. 예를 들면 영국에는 BS, 프랑스에는 NF, 독일에는 DIN이 있다. 이들 국가가 유럽 경제의 3대 축이고, 그들의 표준은 오랜 역사를 갖고 있으며 또한 각국이 자기의 표준만을 적용할 것을 고집하면 유럽역내에서 자유로운 물류의 실현을 어렵다는 결론에 도달하였다.

• 한국재난관리표준학회지
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• 제2권2호
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• pp.85-90
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• 2009

전 세계적인 기후의 변화로 기상 이변이 속출하면서 자연재해로 인한 재산피해와 인명 손실 또한 증가하고 있다. 특히 대부분의 지형이 산지로 이루어진 우리나라의 경우 자연 재해 중 산사태로 인한 피해가 심각한 상황이며, 풍화 깊이가 얕은 국내 자연 사면의 특성상 대규모 산사태보다는 중소규모의 산사태가 광범위하게 발생하고 있다. 그러나 이러한 규모의 산사태를 관측하기 위하여 지금까지 이루어져 왔던 직접측량 방식은 국지적인 결과를 취득하는데 주로 사용되고 많은 인력과 시간이 소모되므로 광범위한 지역의 해석에는 한계가 따른다. 넓은 지역의 산사태를 잘 감지하고 신속한 대처가 이루어질 수 있도록 하기 위해 최근 항공측량이나 인공위성을 활용한 원격탐측의 중요성이 대두되고 있다. 본 연구에서는 높은 투과성을 지닌 JERS-1의 위성 영상을 이용, 2-pass differential interferometry 기술을 통해 대상 지역인 강원도 지역의 지형 변위도를 생성하여 산사태 피해 지역을 탐측하고, 산사태 지역의 탐지 및 분석을 위한 웹 시스템을 구축했다.

• 한국해양환경ㆍ에너지학회지
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• 제3권4호
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• pp.3-22
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• 2000

1998년 하계(6～9월)에 금강하구 주변 해역 11개 정점을 조사하여 공간적인 수질변통 특성을 파악하고, 통계분석 기법의 하나인 요인분석을 동하여 하계 금강하구 주변해역에서의 수질변동 지배요인을 분석하였다. 조사기간 동안 금강하구 주변해역의 화학적산소요구량의 평균농도는 1.36mg/L, 용존무기질소의 평균농도는 28.60㎍-at/L, 용존무기인의 평균농도는 0.48㎍-at/L로 나타났으며, 주성분분석 결과 전체 수질변동의 약 43%를 차지하는 제 1주성분 요인이 담수 유입과 밀접한 관련이 있는 영양염류와 염분의 변화로 나타나, 담수변통 요인이 중요한 역할을 하는 것으로 나타났다.

• Ocean and Polar Research
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• 제30권3호
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• pp.225-238
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• 2008

In order to investigate the effects of intertidal sediments on the nutrient cycle in coastal environments, the benthic fluxes of ammonium, nitrate, nitrite, phosphate, and silicate at two stations on the intertidal flat of Keunso Bay were determined during each season. The efflux of ammonium was observed at S1 and resulted from the diffusion of remineralized ammonium and acceleration caused by the bioirrigation of macrofauna. The influx of ammonium at S2 was probably due to nitrification in the water column. The influx of nitrate was observed at both stations during all seasons, indicating that the nitrate in the pore water was removed by denitrification. Vigorous bioirrigation led to the efflux of dissolved inorganic nitrogen (DIN) at S1, whereas the influx of DIN at S2 was predominantly caused by denitrification. Contrary to the diffusive and bio-irrigated release of remineralized phosphate from the sediment at S1, the influx of phosphate was observed at S2, which may be attributable to adsorption onto iron oxides in the aerobic sediment layer. Silicate, which is produced by the dissolution of siliceous material, was mostly released from the sediment by molecular diffusion and bioirrigation. However, the influx of silicate was observed at S2 during spring and winter, which was ascribed to adsorption by particulate matter or assimilation by benthic microphytes. The annual fluxes of DIN were 328 mmol $m^{-2}yr^{-1}$ at S1 and -435 mmol $m^{-2}yr^{-1}$ at S2. The annual fluxes of phosphate were negative at both sites (-2.8 mmol $m^{-2}yr^{-1}$ at S1 and -28.9 mmol $m^{-2}yr^{-1}$ at S2), whereas the annual fluxes of silicate were positive at both sites (843 mmol $m^{-2}yr^{-1}$ at S1 and 243 mmol $m^{-2}yr^{-1}$ at S2).

• 한국수산과학회지
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• 제31권2호
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• pp.176-185
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• 1998

서식 환경 조사 결과 수온은 1992년에는 웅촌이, 1993 년에는 송도가 높았으며, 염분은 1992년 1월에서 5월을 제외하고는 송도 양식장이 더 높았다. 부유물질과 chlorophyll a 함량 및 저질내 COD는 송도가 높았고, DO, DIP, DIN 및 저질내 총황화물은 웅촌이 높았다. 피조개의 성장과 생리 상태를 분석한 결과, 성장, 연체부지수, 체내 글리코겐 함량과 헤모글로빈 함량 모두 송도의 피조개가 높은 수치를 나타내었다. 또한 송도의 피조개가 생식소 발달도 빨랐다. 본 시험에서 피조개 성장과 생리상태에 영향을 미치는 가장 큰 환경 요인은 먹이생물의 양과 저질의 총황화물량으로 추정되었다.

• 한국환경과학회지
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• 제13권9호
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• pp.789-798
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• 2004

Physicochemical characteristics of Kwangyang Bay, have been investigated on the effects of inputting rivers just after rainy season in summer 2003. The results ranged from 4.96～8.01 mg/L for DO, 1.16～3.09 mg/L for COD, 7.21～67.71 uM for DIN and 0.12～121.84 uM for phosphate. The COD of Yeosu Area was 1.19～3.09 mg/L, Kwangyang Area was 1.23～2.76 mg/L. The COD of Wallae cheon in Yeosu Area was 3.09 mg/L and Donghoan in Kwangyang Area was 2.76 mg/L. The reason of high COD might be industrial sewage of organic chemical plants and iron foundry. DIN of Yeosu Area and Kwangyang Area were 7.21～63.43 ${\mu}M$ and 8.43～67.71 ${\mu}M$ respectively. The average phosphate of Yeosu Area was 23.65 u. The source of phosphate might be industrial sewages of fertilizer plant and phosphate gypsum stocked with high amounts. The metal concentrations were measured in the range of 1.01～175.10 ${\mu}g/L$ for Cu, 0.13～1.78 ${\mu}g/L$ for Cd, 1.13～5.21 ${\mu}g/L$ for Pb, 1.58～13.57 ${\mu}g/L$ for Cr and 1.07～20.68 ${\mu}g/L$ for As. The average Cu concentration was 78.99 ${\mu}g/L$ in Kwangyang Area. The source of Cu might be industrial sewage of iron foundry. The average Cr concentration of Yeosu Area was 9.07 ${\mu}g/L$. That is 2 times higher than Kwangyang Bay 5.74 ${\mu}g/L$, because of sewage of chemical plants.

• 한국환경과학회지
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• 제20권12호
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• pp.1521-1531
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• 2011

This study was carried out to determine the characteristics of the marine environment, including nutritional content, in order to clearly understand the outbreaks of Gonyaulax polygramma in the southern coastal areas in August, 2009. Samples were collected at 13 sites and water temperature and salinity were measured using a CTD. Field surveys were twice: the first between August 5-7, the second between August 22-24. The cell density of G. polygramma was 6,500-10,000 cells $ml^{-1}$ during the $1^{st}$ survey, whereas during the $2^{nd}$ survey the range of the cells was recorded from 8,000 to 12,500 cells $ml^{-1}$. Cochlodinium polykrikoides ranged from 0 to 105 cells $l^{-1}$ during the field survey. In water environments, the majority stations during the $1^{st}$ survey showed a nearly homogeneous water column below $1^{\circ}C$ in temperature, as well as similar profiles of salinity. However, the stratification between the surface and bottom was observed in the $2^{nd}$ survey. Regarding nutrients, Dissolved Inorganic Nitrogen (DIN) in the surface ranged from 0.144 to 0.236 mg $l^{-1}$ during the $1^{st}$ survey, and 0.082-0.228 mg $l^{-1}$ during the $2^{nd}$ survey. DIP (Dissolved Inorganic Phosphorus) did not show any difference in concentration between the $1^{st}$ and $2^{nd}$ survey. During August of 2009, the wind speed in the southern waters remained at around ${\leq}2\;m\;s^{-1}$ for about 60% of time, and there was very little precipitation during the month. Irradiance of ${\geq}10$ hr was shown in the late of August. It is thought that a low level of DIN and salinity play an important role as an essential factor for rapid growth, wide distribution and longer duration of red tide in G. polygramma.