• 대한환경공학회지
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• 제29권9호
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• pp.1003-1012
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• 2007

호수 퇴적물의 용출로 인한 수질오염을 예측하고 퇴적 위치에 따른 용출 특성을 파악하기 위해 환경 조건에 따른 용출 차이를 분석하였다. 분석 항목으로는 질소계열, 인계열, COD를 분석하였으며, 모든 시료의 분석 방법은 호수 내부수의 염도가$(Cl^-)$ 2,000 ppm 이상이므로 해수 수질공정 시험법에 준하여 실시하였다. COD는 혐기조일 경우 A지점에서 C지점으로 갈수록 용출율이 증가한 반면, 호기조일 경우 증 감의 경향성이 없었다. $NH_3$-N의 호기조일 경우 A지점에서 C지점으로 갈수록 용출율이 감소하였고, 반대로 질산화 작용으로 인해 $NO_3$-N과 T-N은 A지점에서 C지점으로 갈수록 용출율이 증가하였다. $NH_3$-N, $NO_3$-N의 혐기조는 A지점에서 C지점으로 갈수록 용출율이 증가하였으나 탈질화 작용으로 인하여 T-N의 용출율은 감소하는 경향을 보였다. $PO_4$-P, T-P의 경우 호기조에서 B지점의 용출율이 가장 낮았으며, 이는 용존 산소의 함량이 많아 무기물이 산화되면서 인의 용출이 억제된 것으로 판단된다. $PO_4$-P의 혐기조일 경우 A지점부터 C지점의 용출율이 서로 유사하였다. COD와 $NO_3$-N의 경우 혐기조보다 호기조에서 용출율이 높았으며, 그 외의 항목에서는 호기조보다 혐기조에서 용출율이 높았다.

• 전기학회논문지
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• 제61권9호
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• pp.1358-1361
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• 2012

This paper presents a study on the analysis for activation time and threshold value of heat detection sensor using HRR(Heat Release Rate). And it is represented to quantity of heat to activate heat detection sensor. The experiment is conducted to measure activation time and HRR of fire detection sensor burning alcohol and n-heptane. In order to burn the alcohol and n-heptane using $43.5cm(L){\times}43.5cm(W){\times}5cm(D)$ and $33cm(L){\times}33cm(L){\times}5cm(D)$ steel pan and the quantity of alcohol and n-heptane are 2.5 L and 650 g, respectively. The results show that peak HRR are in case of alcohol 66.13 kW and in case of n-heptane 151.64 kW, respectively. Total heat releases of heat detection sensor are in case of alcohol approximately 20.7 MJ and in case of n-heptane approximately 18 MJ, respectively.

• 환경영향평가
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• 제7권2호
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• pp.5-14
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• 1998

This study was performed to estimate interrelation between characteristics of sediment and nutrient releare from sediment in Dae-cheong lake. For the investigations, sediments were sampled in June and October 1997 at fish farms, embayment, and the main stream of Dae-cheong lake. Items for investigation are as follows; water content, weight loss on ignition(IG), porosity of sediment, Total Kjeldahl Nitrogen(TKN), content of element(H, N, C), nutrient release rate. Water content and porosity were measured to conjecture the physical trait and grain size. And weight loss on ignition was measured to determine the contents of organic substance. For the determination of nutrient release rate, $PO_4-P$ and $NH_4-N$ concentration of interstitial water and overlying water were measured. Release rate of nutrients which has direct influenced upon the water quality were 0.05-8.63mg-$P/m^2{\cdot}day$ and 4.99-36.56mg-$N/m^2{\cdot}day$. And it was found that release rate was measured higher in the 1st sampling than in the 2nd sampling. And for determination of the humus level of sediment, carbon and nitrogen content were measured by using elemental analyzer. Generally, C/N ratio is used to determine humus level of lake sediment. As a result of elemental analysis, C/N ratio was determined in the range of 7.64~11.55, so humus level of Dae-cheong lake sediment was estimated from mesohumic state to oligohumic state.

• 한국환경농학회지
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• 제20권4호
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• pp.218-224
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• 2001

본 시험은 벼의 전 생육기간에 필요한 질소를 완효성 비료로서 육묘상자에 시용하거나 전량기비로 전층시비할 때 모의 장해나 수량감소 없이 질소이용률을 높이고, 시비노동력을 줄일 수 있는 완효성 비료의 종류와 알맞은 시비량을 찾고자 수행하였다. 완효성 질소비료는 MS 10, MS S10, LCU 80, LCU 100 이었으며, 시용량은 0, 6, 9, 12 kg N/10 a 이었다. 수중 질소용출율과 전기전도도는 MS 10 > LCU 80 ${\fallingdotseq}$ LCU 100 > MS S10 순으로 컸으며, 온도가 높을수록 질소의 용출율이 높았고, EC가 증가하였다. MS 10 시용구에서는 어느 시비량에서나 출아하지 않았고, LCU 80과 LCU 100 처리구에서는 시비량이 증가할수록 입모율이 현저히 저하되었으며, 파종 후 13일에 모가 심하게 시들었다. 모든 MS S10 처리구에서는 입모율이 80% 이상이었고, 파종 후 30일까지 모가 정상적으로 생장하였다. MS S10을 육묘상자와 본답에 전량기비로 시용하였을 때 벼 수량은 두 시비방법간에 차이가 없었으며, 시비량간에는 6, 9, 12 kg N/10a과 요소로서 12 kg N/10a을 4회 분시한 관행시비방법 간에 차이가 없었다. MS S10의 질소이용률은 질소시비량이 증가할수록 감소하였으며, MS S10 시용구가 관행의 요소시비구보다 높았다.

• 한국임상약학회지
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• 제21권4호
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• pp.347-352
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• 2011

Health insurance review & Assessment service (HIRA) has enforced cutting the drug costs when physicians prescribe split extended release drugs, starting from December, 2010. The objective of this study is to analyze extended release and enteric coated drugs on pharmaceutical reimbursement list in Korea, and to investigate the impact and barriers of the health insurance review on splitting extended-release formulation drugs. By using the ingredient code, extended release and enteric coated formulations make up 7.8% of all drugs in April, 2011. The most frequently used drugs are agent affecting circulatory and digestive system. From the extended release and enteric coated formulations (n=112), 34.8% (n=39) were not available in other dosage forms. According to questionnaire survey for 169 pharmacists (response rate: 73.8%), the rate of splitting and crushing of extended release and enteric coated drugs decreased. When pharmacists correct physician's prescription errors, the biggest problem was lack of other dosage forms. So it is necessary to develop variety of other dosage forms, and computerized checking system for splitting extended-release drugs. It is also important to inform physicians and patients in regard to the problems of split prescription of extended release and enteric coated drugs.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2001년도 제16회 학술발표회 논문초록집
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• pp.1-6
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• 2001

In this paper, edge delaminations in cracked composite plates are analytically investigated. A theoretical model based upon a sub-laminate approach is used to determine the strain energy release rate, $G^{ed}$, in [$\pm$$\theta_m$/$90_n$]$_s$ carbon/epoxy laminates loaded in tension. The analysis provides closed-form expressions for the reduced stiffness due to edge delamination and matrix cracking and the total energy release rate. The parameters controlling the laminate behaviour are identified. It is shown that the available energy for edge delamination is increased notably due to transverse ply cracking. Also thermal stresses increase substantially the strain energy release rate and this effect is magnified by the presence of matrix cracking. Prediction for the edge delamination onset strain is presented and compared with experimental data. The analysis could be applied to ceramic matrix composite laminates where similar mechanisms develop, but further experimental evidence is required.

• 한국작물학회지
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• 제46권4호
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• pp.289-295
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• 2001

Experiments were conducted to find out the optimum level of slow release N fertilizers when total amounts of nitrogen required throughout the growing season in paddy were applied in the soil of seedling box. To evaluate the emergence rate and growth of rice seedlings, five levels of Meister (MS) 10, MS S10, and latex coated urea (LCU) which are equivalent to 0, 40, 60, 80, and 100kg N h $a^{-l}$ were mixed in soil of the seedling box. Emergence rate differed depending on the fertilizers and N levels; in MS 10 plots the emergence rate was 40.8% at 40kg N h $a^{-l}$ and no seedlings were emerged at the higher levels, in MS S10 plots higher than 80% at all the N levels, and decreased with the N levels from 70.0% at 40 kg N h $a^{-l}$ to 59.5% at 100kg N h $a^{-l}$ of LCU. Seedling started to wilt at 40 kg N h $a^{-l}$ of MS 10 and 80 and 100 kg N h $a^{-l}$ N of LCU on the 8th day after sowing, while seedling growth was normal at all the levels of MS S10. Field performance of rice was evaluated at the 0, 30, 60, 90, 120kg N h $a^{-l}$ of MS S10 applied in the soil of seedling box and N was not applied in paddy. Grain yield at 90 and 120kg N h $a^{-l}$ of MS S10 was similar to conventional urea split application (120 kg N h $a^{-l}$), but significantly higher compared to 30 and 60kg N h $a^{-l}$ of MS S10. Fertilizer N recovery decreased with N levels and the N recovery at 90 kg N h $a^{-l}$ of MS S10 and conventional urea split application were 62.2 % and 44.2%, respectively, with similar grain yield. The optimum level of MS S10 to be applied in seedling box seems to be about 90 kg N h $a^{-l}$ considering grain yield, price of fertilizer, labor applying fertilizer, and fertilizer N recovery.d fertilizer N recovery.

• Journal of Pharmaceutical Investigation
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• 제30권3호
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• pp.207-211
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• 2000

The objective of this work is to investigate the effect of molecular weight of poly(ethylene oxide) (PEO) and release medium on the release of nifedipine (NP) from PEO tablets containing NP and to get some mechanistic insights into the release of NP. The tablets containing NP were prepared by direct compression, using a flat-faced punch and die. The molecular weights of PEOs used were 200K, 900K, 2000K and 7,000K. The release kinetics were studied for 24 hours in aqueous ethanol solution, using a dissolution tester at $36.5^{\circ}C$ and 100 rpm. Drug release rate increased, as the concentration of ethanol in the dissolution medium increased, due to the increased solubility of NP. As the molecular weight of PEO increased, release rate decreased, due to the slower swelling and dissolution of PEO. The power values obtained by fitting data to the power law expression $(M_t/M_{\infty}=kt^n)$ indicated that, at low ethanol concentration, the release of NP is governed by anomalous diffusion. However, as the ethanol concentration increases, diffusional release becomes to prevail over anomalous or zero-order release. Overall, these results provided some insights into the release of NP from PEO tablet.

• Weed & Turfgrass Science
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• 제4권4호
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• pp.383-389
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• 2015

The use of zoysiagrass (Zoysia japonica Steud.) in the transition zone is limited because of a lack of cold hardiness although zoysiagrass has many advantages compared to other warm-season and cool-season grasses. Late-fall N fertilization is often applied for darker green color of turfgrass in early spring and more extensive root growth without rapid top growth. The objective of the study was to evaluate the effects of late fall N application and turf cover for zoysiagrass spring green-up. Clear polyvinyl chloride (PVC) film was used for turf cover. The amount of N applied were 5 and $10g\;N\;m^{-2}$ for the low and high N rate treatments, respectively. Covered zoysiagrass had greater turfgrass color and quality in early spring than non-covered zoysiagrass. The high N rate had 0.6 to 2.3 greater turfgrass quality than the low N rate on 7 of 9 rating dates. Slow-release N as late fall fertilization is more effective for turfgrass color and quality than fast-release N in spring. Turf cover could reduce the period of yellow zoysiagrass, and the earlier time of spring green-up could be advanced by increasing turfgrass quality and growth of zoysiagrass.

• Archives of Pharmacal Research
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• 제23권4호
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• pp.367-373
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• 2000

Cholic acid, conjugated with amine-terminated poly(W-isopropylacrylamide) (abbreviated as CA/ATPNIPAAm), was synthesized by a N, N'-dicyclohexyl carbodiimide (DCC)-mediated coupling reaction. Self-assembled CA/ATPNIPAAm micelles were prepared by a diafiltration method in aqueous media. The CA/ATPNIPAAm micelles exhibited a lower critical solution temperature (LCST) at $31.5^{\circ}C$. Micelle sizes measured by photon correlation spectroscopy (PCS) were approximately 31.6 $\times$$\times$ 5.8 nm. The CA/ATPNIPAAm micelles were spherical and their thermal size transition was observed by transmission electron microscope (TEM). A fluorescence probe technique was used for determining the micelle formation behavior of CA/ATPNIPAAm in aqueous solutions using Pyrene as a hydrophobic Probe. The critical micelle concentration (CMC) was evaluated as $8.9{\times}0^{-2}$ g/L. A drug release study was performed using indomethacin (IN) as a hydrophobic model drug. The release kinetics of IN from the CA/ATPNIPAAm micelles revealed a thermo-sensitivity by the unique character of poly(N-isopropylacrylamide) i.e. the release rate was higher at $25^{\circ}C$ than at $37^{\circ}C$.