In preparation of silica aerogel-based hybrid coating materials, the combination of hydrophobic aerogel with organic polar binder material is shown to be very limited due to dissimilar surface property between two materials. Accordingly, the surface modification of the aerogel would be required to obtain compatibilized hybrid coating sols with homogeneous dispersion. In this study, the surface of silica aerogel particles was modified by using both surfactant adsorption and heat treatment methods. Four types of surfactants with different molecular weights and HLB values were used to examine the effect of chain length and hydrophilicity. The surface property of the modified aerogel was evaluated in terms of visible observation for aerogel dispersion in water, water contact angle measurement, and FT-IR analysis. In surface modification using surfactants, the effects of surfactant type and content, and mixing time as process parameter on the degree of hydrophilicity for the modified aerogel. In addition, the temperature condition in modification process via heat treatment was revealed to be significant factor to prepare aerogel with highly hydrophilic property.

21종류의 폴리스티렌 용기를 대상으로 용출조건에 따른 용기내 증류수로 용출되는 5종의 VOCs(톨루엔, 스티렌, 에틸벤젠, 이소프로필벤젠 및 n-프로필벤젠)를 Purge&Trap 장치를 연결하여GC-FID로 분석하였다. 각 표준물질은 1~50 ng/ mL의 농도범위에서 직선성(r2 =0.9976~0.9995)을 나타냈으며, 검출한계는 0.041~0.092 ng/mL, 정량한계는 0.135~0.304 ng/mL 이었다. 용출조건은 첫째, 60oC에서 30분, 둘째, 95oC에서 30분, 셋째, 실생활에서 컵라면 섭취시를 고려하여 끓은 물을 부은 후 뚜껑을 덮고 3분간 유지한 다음 뚜껑을 열고 5분 동안 개방하여 용출시키는 것으로 설정하였다. 톨루엔, 에틸벤젠, 이소프로필벤젠 및 n-프로필벤젠은 평균용출량이 모든 조건에서 5 ng/mL 이하로 검출되었으며 스티렌의 경우는 60oC에서 평균용출량이 4.02 ng/mL, 95oC에서는 52.71 ng/mL, 컵라면 섭취시의 조건에서는 17.23 ng/mL로 검출되었다.

The objective of this study was investigate the superovulation treatment and to relate concentrations of blood urea nitrogen(BUN) in Hanwoo donors. Thirty six, at random stages of the estrous cycle, received a CIDR. Four days later, the animals were superovulated with a total of 28AU FSH (Antorin, 2AU=1 ml) administered twice daily in constant doses over 4 days. On the 3th administration of FSH, CIDR was withdrawn and 25 mg PGF2α was administered. Cows were artificially inseminated twice after estrous detection at 12 hr intervals. The cows received 100 μg GnRH at the time of 1st insemination. Embryos were recovered 7 or 8 days after the 1st insemination. Cows with BUN ＜10, 11～18 and ≥19 mg/dl had return of estrus of 34.6, 30.5 and 30.4 days respectively. Return of estrus after superovulation treatment was not significantly lower for cows with blood urea nitrogen (BUN) above 10 mg/dl than for cows with BUN below 10 mg/dl. Cows with BUN ＜10, 11～18 and ≥19 mg/dl had number of transferable embryos of 3.2±1.2, 5.4±1.9 and 4.1±2.1 respectively.

The objective of this study was to determine physiological and mechanical factors effecting on the pregnancy rates following artificial insemination in dairy cattle. Estrus for artificial insemination of cows was checked whether the outflow of mucus from the elements was out flow or not. There were no significant difference of gestation rates with mucus release (31.76%) and without mucus release (24.03%). The pregnancy rates were 39.02% in 10~20mm of follicle size group and 27.08% (p<0.05) in 20~30mm diameter of the follicles. There were not different pregnancy rates between twice inseminated dairy cattle and more than 3 times inseminated cattle. The pregnancy rate was 28.57% under automatic milking system. In contrast, under artificial milking system pregnancy rate was 56.85%. Two systems significantly (p<0.05) were different. These results suggest that pregnancy rates were not effected by physiological system, but mechanical condition.

The objective of this study was to investigate the effects of abnormal ovarian cycles after superovulation treatment of Hanwoo donors. Thirty six, at random stages of the estrous cycle, received a CIDR. Four days later, the animals were superovulated with a total of 28AU FSH (Antorin, 2AU=1 ml) administered twice daily in constant doses over 4 days. On the 3th administration of FSH, CIDR was withdrawn and 25 mg was administered. Cows were artificially inseminated twice after estrous detection at 12 hr intervals. The cows received GnRH at the time of Ind insemination. Embryos were recovered 7 or 8 days after the 1st insemination. The cows were considered to have resumed ovarian cyclicity on the day of ovulation if followed by regular ovarian cycles. 50.0 percentage of the cows (18/36) had normal resumption of ovarian cyclicity (resumption within 40 days after superovulation), and 50.0% (18/36) had delayed resumption(resumption did not occur until>40 days after superovulation). Delayed resumption Type II (first ovulation did not occur until 40 days after superovulation, i.e. delayed first ovulation 33.3%) were the most common types of delayed resumptions. The mean numbers of total ova from < 10 and 10 of corpora lutea (CL) was 7.3 and 13.9, respectively. The number of transferable embryos differed between < 10 and 10 CL was 4.2 and 5.1, respectively. 11.1 percentage of the cows (4/36) did not resumption their ovarian cyclicity until 60 days after superovulation treatment.

Oxygen consumption has been regarded as a useful indicator for assessment of mammalian embryo quality. This study was performed to investigate whether oxygen consumption reflects morphological grade of in vivo derived bovine blastocyst-stage embryos (blastocyst). The oxygen consumption of in vitro produced blastocyst was compared to its total cell number. In addition, pregnant rate was measured after transplantation of in vivo blastocysts with different oxygen consumption. The quality of blastocyst collected on day 7 after artificial insemination was categorized as grade I and II (G I and G II) based on microscopic observation of the morphology. Oxygen consumption of blastocyst was measured using a scanning electrochemical microscopy (SECM) and total cell number of in vitro blastocyst was enumerated by counting cells stained by propidium iodide. Pregnancy of recipient cow was confirmed with rectal palpation after 60 days of embryo transfer. The oxygen consumptions of G I blastocysts were significantly higher than those of G II blastocysts ( versus , p<0.05). Total cell numbers of in vitro blastocysts were 74.8, 90.7, and 110.2 in the oxygen consumption of below 10.0, 10.0~12.0, and over respectively. Total cell number was significantly increased in embryos with high oxygen consumption (p<0.05). Pregnant rate in recipient cow was 0, 50, and 85.7% in the transplantation of embryo with the oxygen consumption of below 10.0, 10.0~12.0, and over , respectively. These results suggest that measurement of oxygen consumption may help increase the pregnant rate of bovine embryos.

본 논문에서는 굴절(refractive) 물체의 광학적 현상들을 실시간으로 표현하는 GPU(Graphics Processing Unit) 기반 렌 더링 알고리즘이 제안되었다. 일반적으로 굴절 물체에 대한 광학적 현상들을 렌더링할 때 포톤 매핑(Photon Mapping) 이 널리 쓰이지만, 포톤 매핑 방법은 계산량이 많기 때문에 게임 등과 같은 실시간 응용분야에는 적합하지 않다. 본 논문에서는 굴절 물체의 앞면, 뒷면의 깊이값의 차이와 굴절 레이(ray)를 이용해 탈출지점을 구하며, 탈출지점의 법선 벡터를 근사하여 빛이 굴절 물체를 통과하면서 발생하는 커스틱스(caustics)현상과 굴절현상을 렌더링한다. 굴절 물체의 반사(reflection) 현상은 프레넬 항(Fresnel term)을 근사(approximation)해서 효율적으로 표현하였다. 또한 HDRI(High Dynamic Range Image)로 환경맵을 구성하여 자연광이 굴절 물체를 통해 굴절되어 보이는 현상을 생성하였다.

Twinning-induced plasticity (TWIP) steels have attracted great attention due to their excellent mechanical properties of high tensile strength (over 800MPa) and high ductility (over 50%), which result from the high strain hardening due to the mechanical twin formation during plastic deformation. The purpose of this study is to investigate the effect of annealing temperature and alloying elements on the mechanical properties of Fe-18Mn-0.6C TWIP steel. In 1.5%Al TWIP steel with 0.123%Ti content, the average recrystallized grain size was reduced to 2.5 μm by cold rolling and annealing at 800˚C for 5 min, because of the pinning effect of the fine TiC carbides on grain coarsening. The tensile strength was decreased and the ductility was improved with the increase of the annealing temperature. However, a reversion of hardness and yield strength happened between 750˚C and 800˚C due to TiC and M3C type precipitation. 0.56% Ni added TWIP steel exhibited relatively lower yield strength, because Ni precipitates were not formed during the annealing process. When this specimen was annealed at 800˚C for 5min, the tensile strength and elongation were revealed at 1096MPa and 61.8%, respectively.

Polyvinyl acetate (PVAc) prepared by emulsion polymerization has broad applications for additive such as paint binder, adhesive for wood and paper due to its low glass transition temperature which help to plasticize substrate resins. Since emulsion polymerization has a disadvantage that surfactant and ionic initiator degrade properties of the product polymer, poly (vinyl acetate-eo-ethyl acrylate) (VAc-EA) was synthesized using potassium persulfate as catalyst and polyvinylalcohol (PVA) as protective colloid to prevent the degradation. The copolymer latex product was internally plasticized and has enhanced adhesion, water resistance during VAc-EA emulsion polymerization. No coagulation and complete conversion occur with the reactant mixture of 10 mmol/L potassium persulfate, 10 mmol/L poly ( vinyl alcohol) (PVA 17). As the concentrations of PVA increase, the viscosity becomes increase.

본 연구는 제주조릿대의 성장단계별 영양소 함량을 분석하고 말에서의 소화율을 검정하여 말 사료자원으로써의 활용가치를 평가하고, 제 주조릿대 군락지 내 말 방목에 따른 제주조릿대의 생산성, 생육특성, 주변 식생의 변화 등을 구명하기 위해 수행되었다. 제주조릿대를 구초 (1년생)와 신초 (당년생)의 성장단계로 분류하여 조단백질, NDF, ADF 및 무기물 함량을 분석했다. 제주마 5두를 이용 제주조릿대 구초와 신초의 전분채취법을 이용한 외관상 소화율을 검정했

본 시험은 2007년부터 2008년까지 톱밥발효우분퇴비 시용수준에 따른 오차드그라스의 생산성과 질산염축적에 미치는 영향을 구명하기 위해 난지축산시험장 조사료포장에서 수행되었다. 시험처리는 화학비료 (CF) 200 kg/ha를 대조구로하여 톱밥발효우분퇴비 (CM)를 질소기준 50, 100, 200%를 두어 처리하였다. 건물수량에서는 2년 평균 CM 200%구가 20,177 kg/ha로 CF구 19,165 kg/ha와 비슷한 수량을 보였다. 처리별 평균 조

본 논문에서는 비선형 강성방정식의 정확성 향상에 관해 연구한다. 대공간 구조물은 대경간을 가볍게 만들기 위해 두께비를 얇게 만들어야 하므로, 구조설계시 구조불안정 검토가 중요하다. 쉘형 구조물의 구조불안정은 초기 조건에 매우 민감하게 반응하며, 이는 대변형을 수반하는 비선형 문제에 귀착하게 된다. 따라서 구조불안정을 정확히 알아보기 위해 비선형 강성방정식의 정확성이 향상 되어야 한다. 본 연구에서는 스페이스 트러스를 해석 모델로 하며 접선 강성방정식과 비선형 강성방정식의 두 이론을 프로그램으로 작성하여 비선형 해석을 수행한다. 두 이론의 해석 결과를 비교 고찰하여 비선형 강성방정식의 정확성 및 수렴성 향상에 대해 검토 한다.

A study was conducted to determine the effects of the cattle manure (CM) application on the botanical composition and micro-mineral contents (Fe, Mn, Cu, Zn) of grazing pasture at the experimental field of Livestock Division, Subtropical Animal Experiment Station, National Institute of Animal Science from year 2003 to 2005. The experiment was arranged in a randomized complete block design with three replications. The treatment consisted of T1: 100% chemical fertilizer (CF 100%), T2: 50% CF +50% CM, T3: 25% CF +75% CM, T4: 100% cattle manure (CM 100%), T5: 100% CM (1st yr.)+ 100% CF (2nd yr.) + 100% CM (3rd yr.), T6: 100% CM (1st yr.)+ 100% CF (2nd yr.)+ 100% CF (3rd yr.). The botanical composition of grassland for grass, legumes, and weeds showed that the rate of legumes was increased in all treatments. The weeds rate in T4 was the highest in comparison to the other treatments. For micro-mineral contents T5 showed the highest average Fe contents of 262.08 ppm and T1 showed the lowest (199.20 ppm). Mn contents was the highest in T1 among the other treatments. Zn contents was the highest in T3 as compared with other treatments. Cu contents was the highest in T6 as compared with other treatments. The results of this experiments indicated that micro-mineral contents of change was effect of legumes increased than treatment