판상형 충전제의 함량과 배향에 따른 PP복합체의 열팽창계수 영향 연구

이기윤(Kee Yoon Lee),이용현(Yong Hyun Lee),정선경(Sun Kyoung Jeoung),황효연(Hyo Yeon Hwang),이승구(Seung Goo Lee) 한국고분자학회 2012 폴리머 Vol.36 No.3

두 가지의 종횡비(ρα=a1/a3 and ρβ=a1/a2)에 의해 특징지어진 3차원 타원체(a1 > a2 > a3)를 사용하여 polypropylene 복합체의 판상형 충전제 함량과 방향이 열팽창률에 미치는 영향에 대해 실험적인 연구를 수행하였다. 측정된 실험적인 값은 Lee와 그의 연구자들이 제안한 이론적인 모델에 의한 계산 값과 비교분석되었다. 판상형충전제로는 운모와 탈크가 사용되었다. 실험 결과로 운모의 경우 종횡비는 ρα= 13.5, ρβ= 1.8이 사용되 어, 20 wt% 함량일때 α11/αm는 약 0.56으로 감소하였으나, α33/αm는 오히려 1.018로 증가함을 보였다. 탈크의 경우의 종횡비는 ρα=3.7, ρβ= 1.4이었고 α11/αm는 0.63으로 감소하였다. 결국 운모와 탈크 모두 그 함량증가에 따라 종단방향과 횡단방향에서 열팽창률은 감소하였으나 수직방향에서는 초기 낮은 충전제 함량에서는 오히려 증가하는 경향을 보였다. Experimental study was performed regarding the effects of disc-like filler orientation and contents on the coefficient of thermal expansion (CTE) of polypropylene composites using the three dimensional ellipsoids (a1 > a2 > a3) analyzed by two aspect ratios(ρα=a1/a3 and ρβ=a1/a2). Measured data were compared with the theoretical approaches proposed by Lee et al. Mica and talc were useed as disk-like fillers in the composites. As experimental results, α11/αm decreased down to ca. 0.56 with mica content of 20 wt% and the aspect ratios, ρα=13.5, ρβ=1.8. However, α33/αm increased to more than 1. In the case of talc, α11/αm decreased to ca. 0.63 with 20 wt% and ρα=3.7, ρβ=1.4. Finally, the longitudinal CTEs (α11) of polypropylene composites decreased as filler contents increased, but normal CTE (α33) increased in the low filler contents like the theory.

Plant regeneration from callus of Iris odaesanensis Y. N. Lee native to Korea via organogenesis

Bae, Kee-Hwa,Yoo, Kyoung-Hwa,Lee, Mi-Hyun,Jeong, Jae-Hun,Choi, Yong-Eui,Yoon, Eui-Soo The Korean Society of Plant Biotechnology 2013 식물생명공학회지 Vol.40 No.3

Iris odaesanensis Y. N. Lee. is an important endangered and native plant belonging to the family Iridaceae in Korea. This study describes a method for rapid micropropagation of this species via from leaf, rhizome and root explants derived calli. Leaf, rhizome and root explants were cultured on Murashige and Skoog (MS) medium supplemented with 2,4-dichlorophenoxy acetic acid (2,4-D) for callus induction. Rhizome explants yielded calli at a frequency of 72% when cultured at 1.0 mg/l 2,4-D. Calli were maintained at 1.0 mg/l 2,4-D. These calli were transferred to MS medium supplemented with 0, 0.5, 1.0, and 2.0 mg/l 2,4-D in combination with 0, 0.5, 1.0, and 3.0 mg/l BA for adventitious shoot induction. The highest number of adventitious shoot (228.9 per petri-dish) were formed at 1.0 mg/l 2,4-D and 1.0 mg/l BA. WPM medium was the best to convert calli into plantlets, where up to 98.2% of calli were regenerated into plantlets. This in vitro propagation protocol should be useful for conservation of this endangered plant.

판상형 충전제의 함량과 배향에 따른 PP복합체의 영률 변화 연구

서상범(Sang Bum Seo),이용현(Yong Hyun Lee),정선경(Sun Kyoung Jeong),이승구(Seung Goo Lee),이기윤(Kee Yoon Lee) 한국고분자학회 2012 폴리머 Vol.36 No.2

이 논문은 판상형 충전제의 함량과 배향에 따라 폴리프로필렌 복합체의 영률 변화에 미치는 영향을 연구 하였다. 이론적인 예측은 Lee와 그의 연구자들에 의해 제안된 두 개의 종횡비, ρα=a1/a3과 ρβ=a1/a2 를 이용하여 3차원 타원체의 형상을 계산하였고 실험값과 비교 분석하였다. 판상형 충전제로 운모와 탈크를 사용하였다. 충전제의 형태는 SEM을 이용해 관찰하였고, 종횡비는 고분자의 흐름을 기준으로 좌표축을 설정하여 통계적 방법으로 계 산하였다. 충전제가 운모인 경우에 ρα=13.5와 ρβ=1.8이었고, 탈크의 경우는 ρα=3.8과 ρβ=1.4이었다. 또한 충전제 의 2개의 종횡비와 함량이 기계적 물성에 미치는 영향을 실험적으로 연구하였다. 운모의 경우 30 wt% 함량일 때 E11이 약 2.7배 향상되었다. 탈크의 경우는 E11이 약 2.3배 향상하였다. This paper studied the effects of the content and the orientation of the disk shape fillers on the modulus of PP composites. The experimental results were compared with the theoretical calculations which included the three dimensional ellipsoids and analyzed by two aspect ratios, ρα=a1/a3 and ρβ=a1/a2 proposed by Lee and his researchers. Mica and talc were used as disk shape fillers in the composites. The shapes of mica and talc were observed by SEM and aspect ratios were statistically calculated. For the case of mica, the average aspect ratios were ρα=13.5 and ρβ=1.8, and for the case of talc, they were ρα=3.8 and ρβ=1.4. Also, the effects of two aspect ratios and the content of filler on the mechanical properties were studied: For 30 wt% of mica, E11 increased up to about 2.7 times, and for the other case of talc, E11 increased up to about 2.3 times, respectively.

수면무호흡증이 혈압에 미치는 영향

이희상,이성훈,조현상,남궁기,한승진,방승규 大韓神經精神醫學會 1997 신경정신의학 Vol.36 No.1

본 연구에서는 수면무호흡증이 혈압에 미치는 영향을 살펴보고자 하였다. 연구대상은 1995년 1월1일부터 1995년 10월 31일까지 코골기와 수면무호흡 증상으로 인해 연정 뇌기능 수면 연구소에 수면다원검사가 의뢰된 140명의 환자를 대상으로 하였으며 그 중에서 원발성 고혈압을 제외한 심혈관계 질환이 있거나 항고혈압제를 복용하고 있는 환자, 그리고 자료가 불충분하거나 수면무호흡증으로 진단되지 않은 24명을 제외하고 나머지 116명을 최종분석 대상으로 하였다. 이들 대상 환자들로부터 얻은 자료를 수면변수와 호흡변수로 나누어 혈압과의 관계를 Pearson 상관관계와 다중회귀분석을 통해 다음과 같은 결과를 얻었다. 1) 평균 수축기 및 확장기 혈압과 유의한 상관관계가 있는 변수는 수면무호흡의 총시간 및 총횟수, 총수면시간중 평균 혈중산소포화도, 무호흡지수, 중추성 수면무호흡의 총시간 및 횟수, 폐쇄성 수면무호흡의 총시간등 이었다. 2) 다중회귀분석 결과 평균 수축기 및 확장기 혈압에 유의한 영향을 미치는 것으로 나타난 변인은 수면무호흡의 총시간이었으며 이것이 평균 수축기 및 확장기 혈압에 미치는 영향의 도는 각각 7.9%와 6.2%였다. 이상의 결과로 볼 때, 수면무호흡증이 혈압에 미치는 영향은 적은 것으로 나타났으며 무호흡의 유형에 관계없이 수면무호흡의 총시간만이 혈압에 영향을 주는 것으로 나타났다. 그리고 중추성 수면무호흡의 경우 평균 혈중 산소포화도의 감소, 각성에 따른 교감신경계 활성도의 증가이외에도 다른 기전에 의해 혈압 상승이 나타날 가능성이 있을 것으로 생각된다. Objects : This study was conducted to investigate the effects of sleep apnea syndromes on th systemic blood pressure. Methods : The subjects were 140 patients who were consulted to Yon-jung brain function and sleep research center for polysomnography due to snoring and sleep apnea from Jan. 1st 1995 to Oct. 31st 1995. Twenty-four out of 140 were excluded due to cardiovascular diseases other than systemic hypertension, antihypertensive medication, inadequate data or diagnosis other than sleep apnea syndrome. The remaining 116 were accepted as proper subjects. Using Pearson's correlation and multiple regression analysis, we looked for the relationship between sleep and respiratory variables to systemic blood pressure. Results : The results were as follows : 1) According to the correlation analysis, statistically significant variables to mean systolic and diastolic blood pressure were the total time and total number of sleep apnea, degree of oxygen saturation of total sleep time, apnea index, total time and total number of central apnea, and the total time of obstructive apnea. 2) According to the multiple regression analysis, only the total time of sleep apnea significantly affected mean systolic and diastolic blood pressure, and the degrees of affection were 7.9% and 6.2% respectively. Conclusion : these findings showed that sleep apnea syndrome had lower influence over systemic blood pressure than expected and regardless of the type, only the total time of sleep apnea influenced systemic blood pressure. In the case of central apnea, mechanisms other than hypoxemia and the increase of sympathetic activity during arousal may make it possible to increase systemic blood pressure.

NAP 공정을 이용한 하수의 질소 및 인 제거에 관한 연구

이성기,송영일,김현중,진성기 조선대학교 환경연구소 2000 環境硏究 Vol.16 No.1

In the process of NAP(Nightsoil Application Process)to get rid of organism, nitrogen and phosphorus, the retention time in an aerobic tank is set up 4hr, 5hr and 6hr with A1, A2 and A3 reactor the sludge return rate is 50% and the internal return rate is 200%. The change of DO, PH, MLSS, MLVSS, Alkalinity, SBOD, SCOD, Organism, SS, Nutrients and the removal rate of those conditions are followed as below. The removal rate of BOD in each reactor is 81.9% in A1, 83.9% in A2 and 87.2% in A3. The average removal rate of COD is 82.3% in A1, 83.6% in A2 and 88.0% in A3. The average removal rate of SS is 81.9% in A1, 83.9% in A2 and 87.2% in A3. The results show that A3 reactor, which has longer retention time than others in the aerobic tank has better removal rate of organism and SS. The average removal rate of T-N in each reactor is 51.4% in A1, 51.8% in A2 and 60.3% in A3. The average removal rate of T-N is 43.4% in A1, 46.0% in A2 and 52.78% in A3. It indicates that the removal rate is higher when the retention time in the aerobic tank is increased. NAP process can be operated that inserting nightsoil which causes to increase C/N in a reactor affects microorganism activity and increases the removal rate of nutrients in the spite of the decrease of the retention time. If the reactor conditions which are internal return rate, return sludge rate and volume of inserting nightsoil are set up properly. The removal rate can be higher in NAP process than in DNR process in which nightsoil is not inserted.

혐기·호기공정을 이용한 생물막법에서 유기물, 질소 및 인제거에 관한 연구

이성기,송영일,김현중,진성기,김은영 조선대학교 환경연구소 2001 環境硏究 Vol.17 No.1

Anoxic and Oxic process with contact media is used to remove an organic matter, nitrogen and phosphorus in sewage which derives from domestic wastewater. Experiments have been done with various conditions that concentration of oxygen can be 3mg/ℓ, 4∼5mg/ℓ and 5∼6mg/ℓ by controlling an retention time can be 10hr, 12hr and 14hr, return rate can be 0%, 100% and 200%. As the concentration of oxygen is 2∼3mg/ℓ. The rate of removal of BOD. COD. SS. T-N and T-P is 87%, 76%, 82%, 34% and 24%. As the concentration of oxygen is 5∼6mg/ℓ. The rate of removal of BOD, COD, SS, T-N and T-P is 92%, 84%, 88%, 45% and 33%. In the rate of removal of an organism, nitrogen and phosphorus thus It well be known that the rate of removal an organic matter, nitrogen and phosphorus will be increased as the concentration of oxygen becomes higher. As th retention time is increased, the rate of removal of BOD, COD, SS, T-N and T-P is gradually higher in the rate of removal of an organic matter, nitrogen and phosphorus. Because contact time and contact area will be increased, which generates active substrate transfer and metabolic react according to increment of retention time. As the return rate is increased. The rate of removal of BOD, COD and SS is likely to be increased. In the case of T-N. It is also increased by 28% at 0% of the return rate and by 60% at 200% of the return rate. In the case of T-P, however, It is deceased, as the return rate is increased by 42% at 0% of the return rate and by 30% at 00% of the return. As the return rate is increased the retention time is decreased, which causes less activity of bacterial which affects that the rate of removal of Phosphorus is decreased.

Magnetron sputtering법으로 제조된 Al-1%Cu/Tungsten Nitride 다층 박막

이기선,서수정,김장현,김남철 공주대학교 자원재활용신소재지역협력센터 2000 2차년도 센터 사업 성과집 Vol.2000 No.1

표면 탄성파 디바이스의 전극재료로 사용되는 Al-1%Cu(4000Å)/tungsten nitride 박막을 magnetron sputtering법으로 제조하고 전기저항을 평가한 결과 비정질상의 tungsten nitride 박막을 제조할 수 있었고, 비정질 형성을 위해서 질소비 (R = N2/(Ar+N2))가 10∼40% 정도 필요하였다. Tungsten nitride 박막의 잔류응력은 비정질이 형성되면서 급격히 감소되었다. 이러한 비정질 박막위에 Al-1%Cu합금막이 형성되었다. 다층막은 453K에서 4시간 동안 열처리함으로써 3.6μΩ-cm의 저항를 나타냈는데, 이는 박막내 결정립 성장과 결정 결함의 감소에 기인하였다. As a power durable-electrode in SAW filter. Al-1%Cu/tungsten nitride multi-layer thin film was fabricated by magnetron sputtering process. Tungsten nitride films had the amorphours phase at the nitrogen ratio, R, ranging from 10~40%. The amorphization could be controlled by nitrogen ratio. R = N2/(N2+Ar) as a sputtering process parameter. Residual stress in tungsten nitride abruptly decreased with the formation of amorphous phase. Al-1%Cu thin film was deposited on the amorphous tungsten nitride. After the multi-layed thin film was annealed for 4 hours at 453K, the resistivity decreased as 3.6 μΩ-cm, which was due to grain growth and reduced crystal defects.

Al-Mn合金의 再結晶時의 時效析出

李海容,趙顯麒 慶北大學校 産業開發硏究所 1985 硏究報告 Vol.13 No.-

The age-precipitation during recrystallization of supersaturated cold-deformed Al-Mn alloy has been investigated by means of measurements of microvickers hardness, electrical resistivity and transmission electron microscopy. The results obtained are summarized as follows 1. Increasing Mn contents, precipitation rate in the range below the recrystallization temperature was accelerated and recrystallization temperature increased. 2. In the range below the recrystallization temperature, most of precipitation was progressed before recrystallization and in the range above the recrystallization temperature, most of precipitation was progressed after recrystallization. 3. Precipitated phases were Al_6Mn phases at all examined temperatures and precipitation hardening was negligibly small.

치과용비귀금속합금의 파단조직에 미치는 주형온도의 영향

이기대,정현곤 慶北大學校 齒科大學 1987 慶北齒大論文集 Vol.4 No.1

The purpose of this study was to investigate the effect of mold temperature on the change in fractured microstructure of Ticonium Premium 100 (Ni-Cr alloy) and Regalloy (Co-Cr alloy). Tensile specimens were casted from the types of alloys by centrifugal casting machine in mold temperatures of 500, 600, 700, 800, 900 and 1,000℃. After testing the tensile strength of castings, the microstructure and the pattern of fracture were investigated. The grain size of Ticonium Premium 100 and Regalloy increased with the increase of mold temperature.

횡성댐 水沒地域內의 植生에 關한 硏究 : 移植對象區域을 中心으로 Centered with Subdivided Area to Select Plants Capable of Transfer

이우철,이기의,서옥하,조현길,백원기,김경진 江原大學校 森林科學硏究所 1997 Journal of Forest Science Vol.13 No.-

본 조사 연구는 江原道 橫成郡 甲川面과 橫成邑 일부를 포함하는 지역에 횡성댐이 건설됨에 따라 수몰되어질 自然生態系의 復元과 保存計劃의 일부로 수행되어졌다. 移植對象區域인 7개소를 중심으로 綠地自然度, 植生現存量 및 생산량 種組成과 植生에 관해 조사하였으며 그 결과는 다음과 같다. 1. 綠地自然度를 등급별로 사정한 결과 등급 0(3.01%), 1(5.3%), 2(28.2%), 3(0.1%), 5(0.2%), 7(4.6%), 7(44.7%), 및 8(13.8%)의 8개 등급으로 구분되었다. 2. 전체조사지역의 現存量과 生産量은 각각 88,436.3 ton/year 과 12,960.3 ton/year 이었다. 3. 조사지역의 陸上植物의 種組成은 86科, 221屬, 306種, 1變種, 3品種의 총 310種으로 조사되었다. 4. 선정된 7개의 植生調査地點에서는 소나무군락이 憂占하며, 그밖에 신갈나무군락, 떡갈나무군락, 상수리나무군락으로 나타났다. This study was carried out in a part of conservative plans recovering natural ecosystem which will be submerged, as Hoengseong dam is being constructed around Hoengseong-Eup and Gabcheon-Myun. The submerged area was divided into 7 small areas to figure out what kinds of species of plants are and will be according to detailed geographic characteristics. In the center of the subdivided areas. Degree of Green Naturality, standing biomass, net 36production per year, and composition of plant species were investigated. The results are as following; 1. The surveyed area was classified into 8 degree by Degree of Green Naturality, and the appeared degree and the rate of occupation were 0(3.01%), 1(5.3%), 2(28.2%), 3(0.1%), 5(0.2%), 7(4.6%), 7(44.7%), 및 8(13.8%). 2. Standing biomass was 88,436.3 ton/year and net production per year was 12,960.3 ton/year. 3. The list of vascular plants identified in this study consisted of 86 families, 221genera, 1 variety, 3 formae and 306 species, totally summiting upto 310 species. 4. The 7 surveyed areas were largely occupied by Pinus community. In addition, there were Quercus mongolica, Quercus dentata, and Quercus acutissima communities.