합성 Hydroxyapatite/Polyacrylic Acid 균질복합체의 제조 및 특성

이석기,이형동,신효순,이병교,Lee, Suk-Kee,Lee, Hyung-Dong,Shin, Hyo-Soon,Lee, Byung-Kyo 한국세라믹학회 2002 한국세라믹학회지 Vol.39 No.11

$Ca(NO_3)_2{\cdot}4H_2O$와 $(NH_4)_2HPO_4$를 사용하여 습식침전법으로 수산화아파타이트(HAp) 분말을 합성하고, 합성된 HAp와 폴리아크릴산(PAA)을 혼합하여 균질의 복합체 4종을 제조하였다. 합성 HAp는 ICP 분석으로 Ca/P비를 정량하였고, HAp/PAA 복합체는 TGA로 열적 성질을 조사하였다. pH 11 및 $60{\circ}C$에서 합성된 HAp의 결정성이 가장 우수하였고, Ca/P비는 1.35~1.49의 범위로 정량되어 Ca 결손의 HAp를 얻었다. HAp/PAA 복합체에서 PAA의 양이 증가함에 따라 비표면적이 증가하였다. 또한 HA/PAa 균질복합체의 $800{\circ}C$에서 무게감량은 3.5~9.6%의 범위로 감소하여 바인더인 PAA가 분해되는 것을 알 수 있었다. HAp/PAA 복합체의 FT-IR 분석결과, HAp의 $Ca^{2+}$ 이온과 PAA의 카르복실기 사이에서 이온결합이 형성되는 사실을 확인할 수 있었다. Hydroxyapatite(HAp) powders were synthesized by wet-precipitation precess using $Ca(NO_3)_2{\cdot}4H_2O$ and $(NH_4)_2HPO_4$ and homogeneous composites of four type were prepared by mixing of synthetic HAp and Polyacrylic Acid(PAA). Ca/P ratio of synthetic HAps was determined using ICP analysis and the thermal property of HAp/PAA composites were investigated by TGA. Good crystalline HAp was obtained at pH 11 and $60{\circ}C$. The ratio of Ca/P in synthetic HAps was quantified in a range of 1.35~1.49, from which Ca-deficient HAp was obtained. The specific surface area of HAp/PAA composite increased with increasing the content of PAA and the weight loss of HAp/PAA composite at $800{\circ}C$ decreased in a range of 3.5~9.6% due to the degradation of PAA binder. From FT-IR analysis of HAp/PAA composite, it was confirmed that the ionic bond between .$Ca^{2+}$ ion of HAp and carboxyl group of PAA was formed.

쌀 첨가비율에 따른 맥주의 품질 특성 평가

이석기,박지영,박혜영,최혜선,조동화,오세관,김현주,Lee, Seuk Ki,Park, Ji-Young,Park, Hye-Young,Choi, Hye Sun,Cho, Donghwa,Oh, Sea-Kwan,Kim, Hyun-Joo 한국식품저장유통학회 2017 한국식품저장유통학회지 Vol.24 No.6

본 연구는 쌀맥주에 적합한 쌀 첨가비율을 선정하기 위해 연질미인 한가루 품종을 이용하여 첨가비율에 따라 맥주를 제조하고 품질특성을 비교분석하였다. 쌀 첨가비율별로 제조한 맥주의 알코올 함량을 측정한 결과 3.93-4.40%로 나타났고, 쌀 첨가비율에 따라 가용성 고형분은 증가하는 것으로 확인되었다. pH는 4.32-4.60의 범위로 나타났으며, 쌀 첨가비율에 따른 유의적인 차이는 없었다. 쌀 첨가비율에 따라 맥주의 산도 및 아미노산도가 낮아지는 경향을 보였으며, 쌀 첨가비율이 증가할수록 명도는 증가한 반면 적색도 및 황색도는 감소하는 경향을 보였다. 특히 쌀 첨가 비율이 높을수록 쓴맛의 강도는 감소하는 것으로 나타났다. 이상의 결과를 종합하여 볼 때, 맥주를 가공하는 데에 있어 쌀의 첨가비율이 증가할수록 쓴맛이 감소되고 색택이 개선되는 등 품질 개선의 효과를 얻었다. 본 연구결과는 쌀맥주를 대량으로 제조하는 데 있어서 품질이 우수한 최적 비율을 선정하는데 기초자료로 활용될 수 있을 것이라고 판단된다. In this study the effect of rice addition on the quality of beer was investigated. Pilot-scale brews were performed with addition ratios of 10, 20, 30, and 40% of brown rice (Oryza sativa L. cv. Hangaru) which were compared with 100% malt beer and commercial beers in terms of quality. Alcohol content of beer was between 3.93 to 4.40%. The total sugar content increased when the rice percent was increased. The pH range of beer were 4.32 and 4.60, which were no significant differences found among by the rate of rice added. Total acidity and amino-acidity decreased corresponding to increasing percent of rice, on the other hand, lightness of beer was increased the increase in percent of rice, while redness and yellowness of beer were decreased. The study demonstrated that the increases of rice addition in beer provided some positive effects on beer quality by decreasing bitterness where as improving beer color.

차량 시뮬레이터를 이용한 안개 대응 시스템 효과 분석

이석기,정준화,Lee,Suk Ki,Jeong,Jun Hwa 한국방재학회 2012 한국방재학회논문집 Vol.12 No.1

도로상의 안개는 대체로 시정거리를 변화시키며 도로 운전자에게 안전에 영향을 준다. 안개 지역 도로에서 연쇄추돌 사고는 주로 후미 추돌 사고이며 사고의 원인은 시거불량과 주행 차량들간의 속도편차 때문이며 주행차량들이 안개시 적절한 주행속도와 차간거리를 유지하는 것이 무엇보다 중요하다. 본 연구에서는 안개 발생시 안전성을 확보할 수 있는 안개 대응 시스템에 대한 설치 효과를 알아보기 위하여 차량 시뮬레이터를 이용하였다. 차량 시뮬레이터 실험을 위한 가상도로는 왕복 2차로 구간인 일반국도 37호선(문산~적성) 눌노천교 주변 1 km 구간으로 운전자 경고등을 25 m와 30 m 간격으로 변경시켰다. 안개 상황은 짙은 안개(시정거리 30 m)와 옅은 안개(시정거리 80 m)로 설정하였다. 피험자는 20대~60대의 성인 남녀 31명을 대상으로 본 실험에 앞서 시뮬레이터에 적응할 수 있는 충분한 연습주행과 사전정보를 제공한 후 주행실험을 한 후 설문조사를 실시하였다. In a foggy day, visible distances depend greatly on the ever-changing concentration of fog. Most of chained rear-end collisions in a foggy day are caused by the significant differences in speeds between vehicles. Then, it is important to minimize the collisions in fog. This study is to estimate the effects of FDWS on drivers` safety behaviors by using a vehicle simulator and a questionnaire survey. A roadway section 1 km long with bidirectional 2 lanes was chosen for the estimation efforts. The test segment was from the Munsan to the Jeokseong county in National Highway 37. Scenarios associated with fog were set as heavy fog. Also, the distance between driver warning lamps was considered by 25 m and 30 m, respectively. The experiment conducted in this study employed the total of 31 adults who were randomly selected from 20- to 60-year old. Before performing the experiment, each subject had enough times to be familiar with the vehicle simulator and was instructed by the guideline of the experiment. After performing the main test, a questionnaire survey was undertaken for each subject.

가교폴리 ( 4- 비닐피리딘 ) 과 메틸오렌지동족체와의 결합에 대한 온도의 존성 . 6 . 가교제의 영향

이석기,박남규,김우식 ( Suck Kee Lee,Nam Kyu Park,Woo Sik Kim ) 한국공업화학회 1990 공업화학 Vol.1 No.2

Various crosslinked poly(4-vinylpyridines) having different degrees of crosslinking were prepared by radical copolymerizations of 4-vinylpyridine with N, N`-2, 6-pyridinebisacrylamide as a crosslinker, The abilities of these crosslinked polymers to bind methyl orange and butyl orange were investigated at various temperatures in a buffer solution of pH 7. The first binding constants were evaluated from the equilibrium binding amounts. The first binding constants against the temperatures showed bell-shaped curves. Also, the first binding constants against the degree of crosslinking showed bell-shaped curves. When the temperature and the degree of crosslinking of maximum binding in the curves of these binding systems were compared with those of previous systems containing crosslinked poly(4-vinylpyridines) prepared by using N , N`-methylenebisacrylamide, N, N`-tetramethy-lenebisacryamide and divinylbenzene as crosslinkers, respectively, they were varied with the crosslinked poly(4-vinyl pyridines) containing different crosslinkers. These results were discussed in terms of the properties of the crosslinkers.

「조합업무안내 」-편리하고 신속한 인터넷보증서 발급서비스(2)

이석기,Lee, Seok-Gi 대한기계설비건설협회 2004 기계설비 Vol.167 No.-

N,N' - 비스아크릴아미드 유도체의 합성

이석기,김우식 ( Suk Kee Lee,Woo Sik Kim ) 한국공업화학회 1997 공업화학 Vol.8 No.6

염화아크릴로일과 여러 종류의 디아민을 트리에틸아민 존재하에서 Schotten-Baumann 반응에 의해 N,N`-비스아크릴아미드 유도체 4종을 합성하였고, IR, ^1H-NMR, 원소분석을 통해 구조를 확인하였다. 합성한 N,N`-헥사메틸렌비스아크릴아미드 (HMBA)와 N,N`-도데카메틸렌비스아크릴아미드 (DMBA)의 수율은 56.0%와 70.4%로 디아민의 메틸렌기의 수가 증가할수록 높아졌다. 또한 N,N`-1,4-페닐렌비스아크릴아미드 (PhBA)와 N,N`-2,6-피리딘비스아크릴아미드(PyBA)의 수율은 각각 80.3% 및 83.1%로 N,N`-알킬렌비스아크릴아미드류보다 높게 나타났다. 합성한 N,N`-비스아크릴아미드 유도체는 여러 종류의 가교고분자 제조에 이용될 수 있다. Four kinds of N,N`-bisacrylamide derivatives were synthesized by Scotten-Baumann reaction from acryloyl chloride and several diamines in the presence of triethylamine, and their chemical structures were identified by IR, ^1H-NMR, and elemental analysis. The yields of the synthesized N,N`-hexamethylenebisacrylamide and N,N`-dodecamethylenebisacrylamide were 56.0% and 70.4%, respectively, and were increased with the increased number of methylene group in the dimines. The yields of the synthesized N,N`-1,4-phenylenebisacrylamide and N,N`-2,6-pyridinebisacrylamide were 80.3% and 83.1%, respectively, which were higher than those of the alkylenebisacrylamide derivatives. The synthesized N,N`-bisacrylamide derivatives can be used to prepare various crosslinked polymers.

신생아 기흉의 임상적 고찰

이석기,임진수,최형호,Lee, Seok-Gi,Im, Jin-Su,Choe, Hyeong-Ho 대한흉부심장혈관외과학회 1995 Journal of Chest Surgery (J Chest Surg) Vol.28 No.12

From 1991 to 1994, we experienced 24 cases of neonatal pneumothorax who were admitted to the Neonatal Intensive Care Unit[NICU , Chosun University Hospital. The Following results were obtained.1 The incidence of neonatal pneumothorax was 0.70%, and there were 8 spontaneous pneumothoraces and 16 secondary pneumothoraces. 2 The clinical manifestation of neonatal pneumothorax was as followed. Male infant was dominant[M:F=2:1 , the onset was within 24 hours in the majority[83% , and the right side[62% was more frequent than the left side. The gestation duration and birth weight show no correlation with underlying neonatal pneumothorax. The pulmonary diseases were meconium aspiration syndrome and hyaline membrane disease, and the incidence of those was 58%. Meconium aspiration syndrome occurred earlier than hyaline membrane disease. Symptoms and signs were tachypnea[46% , cyanosis[21% , irritability[13% , chest retraction[8% and apnea[8% .3 The treatments performed were oxygen therapy[17% , thoracentesis[4% and closed thoracostomy with underwater seal drainage[79% . The Mean duration of air leakage was 11.7 hours, and the mean drainage time was 4.35$\pm$1.3day. 4 The overall hospital mortality was 33%, and the rate of complication was 46%. The complications were metabolic acidosis, atelectasis, pleural effusion, pulmonary hemorrhage and pneumonia. We concluded that the prognosis was related to the underlying pulmonary disease.

NaOH 첨착활성탄의 H₂S 흡착능

이석기,박영성,Lee, Suk-Ki,Park, Yeong-Seong 대한환경공학회 2000 대한환경공학회지 Vol.22 No.5

본 연구에서는 NaOH로 첨착(함침)시킨 활성탄의 $H_2S$ 흡착특성을 고찰하였다. 첨착시약으로 사용된 NaOH용액의 농도는 1~8 N이며, 활성탄의 입자크기는 $8{\times}30$ mesh가 적용되었다. 실험결과, 첨착율이 0.87~5.8% 범위내에서 증가될수록 BET 표면적은 $1050m^2/g$에서 $783m^2/g$로 감소되며, 표면산도는 0.541 meq/g-AC에서 0 meq/g-AC으로 감소하고, pH는 9.56에서 10.86으로 증가하는 것으로 밝혀졌다. 또한 NaOH로 첨착시킨 활성탄의 $H_2S$ 평형흡착능은 흡착온도와 $H_2S$ 가스농도에 비례함을 보였으며, 흡착온도가 $45^{\circ}C$일 때 17.87~30.34 mg/g-AC 범위의 $H_2S$ 평형흡착능을 보임으로써 비첨착활성탄에 비해 2~3배 높은 수준을 나타냄을 알 수 있었다. $H_2S$ adsorption characteristics of activated carbon adsorbent impregnated with NaOH were investigated. The concentrations of NaOH reagent were 1~8N and the particle size of activated carbon was $8{\times}30$ mesh. The experimental results showed that the BET surface area decreases from $1050m^2/g$ to $783m^2/g$ and acidity of activated carbon decreases from 0.541 meq/g-AC to 0 meq/g-AC, while pH increases from 9.56 to 10.86 when the impregnation ratio increases from 0.87% to 5.8%. It was also found that the $H_2S$ adsorption equilibrium capacity of activated carbon impregnated with NaOH increases with increasing temperature and $H_2S$ concentration and varies in the range of 17.87~30.34 mg/g-AC at adsorption temperature of $45^{\circ}C$, which is 2~3 times larger than that of pure activated carbon.

여러가지 물혼합용매 속에서 p-Chlorobenzyl Chloride의 가용매분해

이석기,이억석,Lee, Suk-Kee,Lee, Euk-Suk 대한화학회 1971 대한화학회지 Vol.15 No.4

The thermodynamic parameters for the solvolysis of the p-chlorobenzyl chloride taking place in the various aqueous mixtures were determined. From the application of these data to the formula ${\delta}_M{\Delta}H^{\neq}=a'Y+b{\delta}_M{\Delta}S^{\neq}$ the following conclusion was obtained: That the substrate constant a' differs in different aqueous solvent was found, and using each a' value the solvolysis mechanism of p-chlorobenzyl chloride in each aqueous mixture can be determined.

국내 시판 엿기름의 품질 특성 분석

이석기,박혜영,최혜선,최인덕,박지영,조동화,오세관,한상익,우관식,김현주,Lee, Seuk Ki,Park, Hye Young,Choi, Hye Sun,Choi, In-Duck,Park, Ji Young,Cho, Dong Hwa,Oh, Sea-Kwan,Han, Sang Ik,Woo, Koan Sik,Kim, Hyun-Joo 한국식품영양학회 2018 韓國食品營養學會誌 Vol.31 No.5

As basic research for optimal barley cultivars selection and technical development for quality maintenance, a total of 21 commercial malt products (for making 'Sikhye', a traditional Korean sweet drink) were collected from the Korean market. And then we analyzed the component of the barley malt products as well as conducted comparative analysis on enzyme activity and quality characteristics of the commercial barley malt products. Of the 21 barley malt products, 12 were made from 100 % barley. The result of analyzing general components of barley malts turned out different level of components; moisture 4.91~11.99%, lipid 1.71~2.48%, protein 7.80~11.97%, carbohydrate 73.64~82.24%, total starch 5.50~8.22%, reducing sugar 3.64~14.44%. As a result of measuring enzyme activity of barley malts, there was a wide range of activity difference by the product; diastatic power $36.80{\sim}94.30^{\circ}$, ${\alpha}$-amylase activity 18.17~186.50 unit/g, ${\beta}$-amylase activity 6.53~25.05 unit/g. The results of this study would be used as basic data for optimal cultivars selection to produce barley malts and technical development for quality maintenance.