• 약학회지
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• 제24권1호
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• pp.11-14
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• 1980

In order to increase the gastro-intestinal absorption of cephalexin, a new cephalexin phthalidyl ester was synthetized. Comparative studies of cephalexin phthalidyl ester in the gastro-intestinal absorption were conducted after oral administration in rabbits. The amounts of cephalexin in plasma were determined by a fluorometric method. Cephalexin phthalexin phthalidyl ester could not be identified in plasma, but only cephalexin was found by TLC method. In comparison with cephalexin, cephalexin phthalidyl ester produced much higher plasma levels of cephalexin than did cephalexin itself after its oral administration in rabbits.

• Tribology and Lubricants
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• 제17권2호
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• pp.124-129
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• 2001

The electrical and rheological behaviors of the cellulose phosphate ester suspension in the silicone oil were investigated. Cellulose phosphate ester suspension showed a typical ER response (Bingham flow behavior) upon application of an electric field. The shear stress for the cellulose phosphate ester suspension exhibited a linear dependence on the volume fraction of particles and a square power of the electric field. On the basis of the experimental results, cellulose phosphate ester suspension correlated with the conduction model of Tang et al, and found to be an ER fluid.

• 한국식품과학회지
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• 제18권5호
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• pp.364-371
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• 1986

High-ester pectin을 HCI 단독 또는 HCI 과 $NH_4OH$를 병용하여 demethylation 시킨뒤 얻어진 low-ester pectin(LM pectin)으로 gel을 제조하였다. LM pectin gel의 단단함과 강도(强度)를 측정한 결과 HCI로 처리된 LM pectin gel은 일반적으로 강도(强度)가 약하고 거칠며 탄력이 없었다. 반면 $HCl-NH_4OH$로 처리한 LM pectin gel은 텍스쳐가 부드럽고 탄력이 좋았다. 물리적 성질에 대한 LM pectin의 화학적 조성의 상관 관계에서 단단함(Sag값)에 대한 ester함량 및 분자량, 그리고 강도(强度)(puncture stress)에 대한 amide 및 ester함량 EH는 분자량 간에는 유의성 있는 관계가 밝혀졌다. 상관성이 높은 화학적 인자에서 LM pectin gel의 물리적 성질을 예측할 수 있는 관계식을 산출하였다.

• Journal of Pharmaceutical Investigation
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• 제18권3호
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• pp.139-144
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• 1988

Piperacillin phthalidyl ester was synthesized by reacting piperacillin with triethylamine and bromophthalide in acetone and its chemical structure was determined by UV, IR, and PMR. The partition coefficient of the ester was increased and the ester was more lipophilic and less water soluble than piperacillin. The ester did not show the antimicrobial activity against Bacillus subtilis ATCC 6633 in vitro, but when hydrolyzed, the parent drug of ester, piperacillin, revealed antimicrobial activity in vivo. After a single oral dose of both piperacillin and the ester to rabbits, the serum piperacillin concentration was measured by bioassay. The ester exhibited improved pharmatokinetic characteristics: $T_{max}\;of\;2hr,\;C_{max}\;of\;4.26{\mu}g{\cdot}ml^{-1},K_{el}\;of\;0.057hr^{-1},\;and\;total\;AUC\;of\;85.42{\mu}g{\cdot}hr{\cdot}ml^{-1}$. Piperacillin on the other hand, did not exhibit any gastro-intestinal absorption.

• 생명과학회지
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• 제19권4호
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• pp.538-542
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• 2009

본 연구는 itaconic acid로부터 합성한 새로운 soft contact lens 소재의 함수율과 산소투과도를 확인 하였다. Soft contact lens의 새로운 polymer소재 개발을 위하여 기본 monomer인 HEMA (2-hydroxyethyl methacrylate)와 가교제로서 EGDMA (ethylene glycol dimethacrylate) 그리고 A. itaconicus의 발효에 의해 생산된 itaconic acid로부터 얻어진 mono-ester 1과 di-ester 2를 새로운 첨가제로 사용하여 중합반응을 시도하였다. Soft contact lens의 새로운 폴리머 소재들은 HEMA와 mono-ester 1 또는 di-ester 2를 서로 다른 비율로 합성하여 함수율(water content)과 산소투과도(oxygen permeability)를 분석하였다. Polymer 형성을 위한 HEMA와 additive의 혼합에서 HEMA/mono-ester 1의 혼합물은 HEMA/di-ester 2 보다 함수율과 산소투과도가 뛰어 났으며 HEMA와 첨가제 mono-ester 1 (15%)를 이용한 중합의 경우, 제작된 soft contact lens의 함수율과 산소투과도는 각각 57.7%와 28.6 Dk로 좋은 값을 나타냈다. 새로운 소재를 사용하여 만든 soft contact lens의 함수율과 산소투과도는 우수하게 나타났다.

• 대한화학회지
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• 제35권1호
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• pp.85-89
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• 1991

한국 남해안 소흑산도에서 채집한 해면 V.japonica H.로부터 통상적인tetradecanoic 및 hexadecanoic methyl ester 이외에 탄소가 홀수인 pentadecanoic, heptadecanoic methyl ester와 가지달린 12-methyltetradecanoic, 14-methylpentadecanoic, 15-methylhexadecanoic 및 14-methylhexadecanoic methyl ester가 발견되었으며, 주 sterol 성분으로는 cholesterol과 소량의 ergost-25-ene-3,5,6-triol이 검출되었다. 한편, 여수 돌산도에서 채집한 해면 H.sinapium의 주 sterol성분은 5${\alpha}$-cholestan-3${\beta}$-ol이었고 cholesterol은 소량으로 얻어졌다. 지방산으로는 팔미틴산, 팔미토레인산, 올레인산, 스테아린산 및 리놀레인산 에틸에스터 이외에 상당량의 arachidonic산 에틸에스터가 함유되어 있었다. 상기 지역에서 채집한 또 다른 해면에서는 상당량의 tetradecanoic tetradecyl 및 hexadecyl ester와 sterol 성분으로 cholesteryl acetic 및 fatty acid ester가 함유되어 있었다.

• Korean Chemical Engineering Research
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• 제56권2호
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• pp.275-280
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• 2018

Methyl ester derived from coconut oil is very interesting to study since it contains free-fatty acid with chemical structure of medium carbon chain ($C_{12}-C_{14}$), so the methyl ester obtained from its part can be a biodiesel and another partially into biokerosene. The use of heterogeneous catalysts in the production of methyl ester requires severe conditions (high pressure and high temperature), while at low temperature and atmospheric conditions, yield of methyl ester is relatively very low. By using microwave irradiation trans-esterification reaction with heterogeneous catalysts, it is expected to be much faster and can give higher yields. Therefore, we studied the production of methyl ester from coconut oil using CaO catalyst assisted by microwave. Our aim was to find a kinetic model of methyl ester production through a transesterification process from coconut oil assisted by microwave using heterogeneous CaO catalyst. The experimental apparatus consisted of a batch reactor placed in a microwave oven equipped with a condenser, stirrer and temperature controllers. Batch process was conducted at atmospheric pressure with a variation of CaO catalyst concentration (0.5; 1.0; 1.5; 2.0, 2.5%) and microwave power (100, 264 and 400 W). In general, the production process of methyl esters by heterogeneous catalyst will obtain three layers, wherein the first layer is the product of methyl ester, the second layer is glycerol and the third layer is the catalyst. The experimental results show that the yield of methyl ester increases along with the increase of microwave power, catalyst concentration and reaction time. Kinetic model of methyl ester production can be represented by the following equation: $-r_{TG}=1.7{\cdot}10^6{_e}{\frac{-43.86}{RT}}C_{TG}$.

• 한국전기전자재료학회논문지
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• 제19권1호
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• pp.40-45
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• 2006

Electrical insulation is one of the most important parts in a high voltage apparatus. Traditionally mineral oils and synthetic esters have been widely used as dielectric coolants for power transformers. Recently, researchers are interested in the environmentally friendly vegetable oil from the environmental viewpoint. This paper reports on the synthesis and characterization of soybean based ester oils. Two different types of soybean based transformer oils, named as methyl ester and isopropyl ester were synthesized. The synthesis of these esters was achieved by transesterification reactions between soybean oil and alcohol in the presence of catalyst. The GC and NMR spectroscopic analysis of the esters have been performed. It was observed that isopropyl ester has better thermal resistance than methyl ester by TGA. Also, two esters have a good breakdown voltage and electrical resistance.

• 한국인쇄학회지
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• 제29권3호
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• pp.1-16
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• 2011

In these days, according to increased environmental regulations, to reduce the VOC content in paints and inks efforts are now in progress. A lot of research have progressed hydrocarbon solvents substitute with vegetable oil or ester in the printing ink but it is restricted to use vegetable oil in the inks because of high molecular weight and viscosity. Oil ester currently developed for printing inks still have some drawbacks, but overall the printability and print quality when using ester than hydrocarbon solvents are showing good results. Thus, in this paper, I studied about the properties variation of the varnish and inks according to vegetable ester, after I reacted vegetable ester using the vegetable fatty acid and ethyl alcohol, butyl alcohol. The compared in order of average molecular weight by the GPC method, rheological properties were found by rotational rheometer, and emulsion behavior were compared by high speed emulsification tester.

• 한국염색가공학회지
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• 제9권3호
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• pp.50-55
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• 1997

Ester섬유는 대표적인 소수성 섬유인데, 소수성 섬유의 염색중에서 black은 가장 가공량이 많은 색이라고 널리 알려져 있지만, 그 중에서도 ester섬유 또는 ester섬유와 triacetate섬유의 혼방품 등을 소재로 한 정장복의 짙은 검정색은 formal black 이라고 불리워지고, 그외의 검정색과 구별되고 있으며, 그 가공량도 대단히 많아지는 추세이다. 이 글에서는, 연색성과 재현성이란 차원에서 특징있는 일본화약주식회사의 신제품 Kayalon Polyester Jet Black V Paste의 소개를 겸해서, formal black의 염색가공과 한국 실정에 맞는 실예에 관해서 기술해 보고자 한다.