• 한국포장학회지
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• 제19권3호
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• pp.139-141
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• 2013

인체 유해성 및 환경적 유해성 문제로 염소계 합성수지 포장재에 대한 사용규제가 강화되고 있다. 본 연구에서는 염소계 합성수지 포장재 여부를 확인하기 위한 진단시약을 개발하고자 하였으며, 메탄올($CH_3OH$)에 수산화나트륨(NaOH)을 포화상태로 용해시킨 용액을 피리딘(Pyridine)과 동일 비율로 혼합하여 제조하였다. 진단 용액과 염소기의 화학적 반응 메카니즘 분석 및 발색 실험을 통해 염소계 합성수지 포장재 진단용액으로서의 유효성을 확인하였다. 진단시약에 의한 발색 분석기법은 측정이 간단하고, 분석비용이 저렴하며, 현장에서 즉시 확인이 가능하므로 산업현장에서 활용성이 높을 것으로 판단된다.

• 한국세라믹학회지
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• 제27권7호
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• pp.851-860
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• 1990

The hydrolysis-precipitation reaction of mixed aluminum salt solutions of aluminum sulfate, aluminum nitrate, and urea has been investigated to obtain narrow-sized and unagglomerated fine spherical precipitates of aluminum hydroxide required for coating core particles. The hydrolysis-precipitatin reaction could be controlled to be appropriate to coating processes by usign urea as a pH control-agent. As the concetration of total Al3+ ion and the molar ratio of SO42-/Al3+ in starting solutions became smaller and also as the vol. ratio of water/solution for hydrolyzing mixed aluminum salt solution became larger, the morphology of precipitates tended to be more unagglomerated and spherical, while their size(0.5longrightarrow0.05${\mu}{\textrm}{m}$) to be smaller. The optimum hydrolysis condition for coating processes was to hydrolyze the mixed aluminum salt solution, in which the molar ratio of SO42-/Al3+ was 0.75, while the amount of water corresponding to the vol. ratio of water/solution of 15. The precipitate was the aluminum hydroxide which sulfate ions were strongly adsorbed on and the maximum yield in the hydrolysis-precipitation reaction was about 20%.

• Journal of Plant Biotechnology
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• 제6권2호
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• pp.107-111
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• 2004

To establish an efficient acclimation system for regenerated plantlets of soybean, we used various media with hydroponic nutrient solutions before regenerants were transplanted into soil. The hydroponic nutrient solution was essential for the survival of the plantlets. The vermiculite with nutrient solution at pH 5.5 was found to be the best medium with 97-100% survival rate and better growth of regenerants plantlets. Regeneraed grew best in the following order of solutions: Yoshida solution, modified Yoshida solution, SoyI, Soy II, and MS medium. However, Soy I solution (EC 2.9 mS/cm), developed by the Honam Agricultural Research Institute proved to be the most effective for acclimation in terms of the time required for vigorous growth and economical use of chemicals.

• Journal of Chest Surgery
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• 제25권2호
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• pp.131-136
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• 1992

The effect of temperature of cardioplegic solution on myocardial preservation was studied using isolated rat heart perfusion technique. Twenty Sprague-Dawley rats, weighing 120~140gm, were pretreated with intraperitoneal injection of heparin sodium[300u/kg] and then the hearts were excised after cervical herniation 30 minutes later. The hearts were perfused in isolated working heart apparatus with oxygenated modified Tyrode solution at 37oC. After 10 minutes of non working heart perfusion, the hearts were subjected to arrest for 30 minutes by administration of 5cc cardioplegic solution at the temperature of 4oC [Group I ], 15oC [Group II], 25oC [Group III], 37oC[Group IV]. At the same time, the topical cooling of heart was performed using ice saline. After arrest, the hearts were reperfused by non working heart perfusion for 1 hour with modified Tyrode solution at 37oC. The CPK, GOT and LDH in reperfusate were measured at 5,20,40,60 minutes after start of reperfusion. With the values of those, we compared the effect of temperature of cardioplegic solution on myocardial preservation. The results were as follows; 1. The enzyme values in reperfusate were highest at 5 minute and after then declined. 2. At 5 minutes after reperfusion, the enzyme values in Group I were lower than those in other Groups. These results suggest that the cardioplegic solutions using for cardiac arrest and myocardial protection can be working better at 4oC than at any other temperature.

• Ocean Systems Engineering
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• 제13권2호
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• pp.123-146
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• 2023

In this paper, Moore-Gibson-Thompson theory of thermoelasticity is considered to investigate the fundamental solution and vibration of plane wave in an isotropic photothermoelastic solid. The governing equations are made dimensionless for further investigation. The dimensionless equations are expressed in terms of elementary functions by assuming time harmonic variation of the field variables (displacement, temperature distribution and carrier density distribution). Fundamental solutions are constructed for the system of equations for steady oscillation. Also some preliminary properties of the solution are explored. In the second part, the vibration of plane waves are examined by expressing the governing equation for two dimensional case. It is found that for the non-trivial solution of the equation yield that there exist three longitudinal waves which advance with the distinct speed, and one transverse wave which is free from thermal and carrier density response. The impact of various models (i)Moore-Gibson-Thomson thermoelastic (MGTE)(2019), (ii) Lord and Shulman's (LS)(1967) , (iii) Green and Naghdi type-II(GN-II)(1993) and (iv) Green and Naghdi type-III(GN-III)(1992) on the attributes of waves i.e., phase velocity, attenuation coefficient, specific loss and penetration depth are elaborated by plotting various figures of physical quantities. Various particular cases of interest are also deduced from the present investigations. The results obtained can be used to delineate various semiconductor elements during the coupled thermal, plasma and elastic wave and also find the application in the material and engineering sciences.

• Journal of the Korean Wood Science and Technology
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• 제12권3호
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• pp.25-34
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• 1984

This experiment was carried out to investigate the effects of monosaccharides extracted by saturated portland cement solution on the cement setting in comparision with the inhibitory index (I) of each lignocellulosic-cement system. The wood species which have been widely reforested in Korea, Populus alba-grandulosa, Larix leptolepis, Abies holophylla, Pinus koraiensis, Pinus rigida, Pinus densiflora and agricultural wastes of rice husk and rice stalk were used at this study. The wood meal, 0.50g on dry weight basis, through 0.83 mm(20 mesh) and retained on 0.35mm (40 mesh) screen was extracted by 25 ml saturated portland cement solution and the pH of saturated portland cement solution Was 12.7. To eliminate cation exsisting in the extracted solution, the cation exchange column was used (Fig. 4). Afterwards the extracted monosaccharides were reduced into alditols with sodium borohydride and analyzed by the gas-liquid chromatography for xylan, mannan, arabinan, galactan, gluean. The heat of cement hydration for lignocellulosic-cement system was measured in Dewar flask (Fig. 2). And then the inhibitory indices were calculated from maximum hydration temperature, time and maximum slops of hydration curve of ligno cellulosic-cement systems. The results obtained were as follows; (1) The inhibitory index of pines-Pinus rigida (I=29.33) and Pinus densiflora (I=35.76), were lower than that of poplar-Populus alba-glandulosa (I=41.48), and the index of Larix ieptoiepis (I=73.00) was the highest among eight lignocellulosic-cement systems, and accordingly both Pinus rigida and Pinus des(flora were seemed to be good wood species for wood-cement composite manufacture. (2) In case of Pinus rigida, the inhibitory index was 29.33 and the ratio of the hexoses to the pemoses was 6.04 and in case of Larix leptolepis, the index and the ratio were 73.00 and 35.19, respectively. Therefore the inhibitory index increased with increasing the ratios of the hexoses to the pentoses. (3) The richer amount of xylose and mannose in species caused decreasing the slops of the hydration curve of the lignocellulosic-cement system, prohahly due to the chemical adsorption of the acetyl groups in the hemicellulose on the surface of cement grains. (4) The amoun of xylose and mannose were significant to the inhibitory index of each lignocellulosic-cement system but any specific relation between the amount of glucose and inhibitory index was not found.

• Bulletin of the Korean Chemical Society
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• 제2권4호
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• pp.142-147
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• 1981

A blend polymeric system composed of poly(methyl methacrylate) (PMMA or PM) and polystyrene (PS) dissolved in chloroform was rheologically studied. The viscosities ${\eta}_{bl}$ of the blend system with various blending ratios ${\chi}$ changing from zero (pure PS solution) to unity (pure PMMA solution) were measured at $25{\circ}C$ as a function of shear rates ${\dot{s}}$ by using a Couette type viscometer. ${\eta}_{bl}$ at a given ${\dot{s}}$ decreased exponentially with ${\chi}$ reaching asymptotic constant value of ${\eta}_{bl}$ ; ${\eta}_{bl}$ at a given ${\chi}$ is greater at a smaller ${\dot{s}}$. These results are explained by using Ree-Erying's theory of viscosity, ${\eta}_{bl}=(x_1{\beta}_1/{\alpha}_1)_{b}_1＋ (x_2{\beta}_2/{\alpha}_2)_{bl}[sinh^{-1}{\beta}_2(bl) {\dot{s}}]/{\beta}_2(bl){\dot{s}}$. The Gibbs activation energy ${\Delta}G_i^\neq$(i = 2 for non-Newtonian units) entering into the intrinsic relaxation time ${\beta}$ is represented by a linear combination ${\Delta}G_i^\neq(bl) ={\chi}{\Delta}G_i^{\neq}_{iPM}+(1-{\chi}){\Delta}G_i^{\neq}_{iPS}$;the intrinsic shear modulus$[[\alpha}_i]^{-1}$ is also represented by $[{\alpha}_i(bl)]^{-1}={\chi}[{\alpha}_{iPM}]^{-1}+(1-{\chi})[{\alpha}_{iPS}]^{-1}$ and the fraction of area on a shear surface occupied by the ith flow units $x_i(bl)$ is similarly represented, i.e., $x_i(bl) = {\chi}x_{iPM}+(1-{\chi})x_{iPS}$. By using these ideas the Ree-Eyring equation was rewritten which explained the experimental results satisfactorily.

• 물류혁신 컨퍼런스
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• 제9권2호
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• pp.281-298
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• 2001

• 대한화학회지
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• 제17권5호
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• pp.378-384
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• 1973

요오드화칼륨으로부터 요오드산칼륨까지의 양극산화시 그 반응의 내용을 검토키 위하여 전착과산화납 및 백금양극을 사용하여 각종 농도의 요오드화칼륨 수용액중에서 분극곡선을 측정한 결과 요오드화칼륨의 1.5M이하에서 한계전류가 존재하며 0.1M의 수산화칼륨을 가하였을때는 한계전류는 나타나지 않음을 알았다. 한편 백금양극의 경우에는 과산화납양극에서와 같이 희박한 요오드화 칼륨수용액중에서 한계전류가 나타나지 않으며 이는 과산화납양극표면에서 $PbO_2+2I^{-}+2H^+{\to}PbO+I_2+H_{2}O$와 같은 화학반응에 기인함을 알았다. 무격막전해조를 사용하여 요오드화염으로부터 요오드산염까지의 전해제조시 가장 효율적인 전해조건에 관하여서도 검토한 결과, (a)환원방지제인 중크롬산칼륨의 첨가는 0.1g/l의 농도가 적당하였으며, (b)전해온도는 전류효율에 큰 영향을 미치지 않았으며, (c)전류밀도가 증가함에 따라 전류효율은 상승하였고, (d)전해중 전해액의 액성은 약알카리성이 가장 효율적이었다.

• 대한약침학회지
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• 제3권2호
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• pp.153-168
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• 2000

This study was designed to study on major components of various Bee Venom(Bee Venom by electrical stimulation in Korea; K-BV I, Bee Venom by Microwave stimulation in Korea; K -BV II, 0.5rng/ml, Fu Yu Pharmaceutical Factory, China; C-BV, 1mg /ml, Monmouth Pain Institute, Inc., U.S.A.; A-BV) using Electrophoresis. The results were summarized as follows: 1. In 1:4000 Bee Venom solution rate, the band was not displayed distinctly usmg Electrophoresis. But in 1: 1000, the band showed clearly. 2. The results of Electrophoresis at solution rate 1:1000, K-BV I and K-BVII showed similar band. 3. The molecular weight of Phospholipase $A_2$ was known as 19,000 but its band was seen at 17,000 in Electrophoresis. 4. Protein concentration of Bee Venom by Lowry method was different at solution rate 1:4000 ; C-BV was $250{wmu}g/ml,\;K-BV\;I\;was\;190{wmu}g/ml,\;K-BVII\;was\;160{wmu}/ml\;and\;C-BV\;was\;45{wmu}/ml5$. Electrophoresis method was unuseful for analysis of Bee Venom when solution rate is above 1:4000 but Protein concentration of Bee Venom by Lowry method was possible. These data from the study can be applied to establish the standard measurement of Bee Venom and prevent pure bee venom from mixing of another components. I think it is desirable to study more about safety of Bee Venom as time goes by.