• 한국자동차공학회논문집
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• 제22권5호
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• pp.13-19
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• 2014

Urea-SCR system is the selective catalytic reduction to reduce nitrogen oxides ($NO_x$) emitted from diesel vehicles. The objective of this study is numerical analysis of 3-dimensional unsteady melting problems of frozen urea by using an electric heater. It can be applied to determine capacity of power with respect to time and the location of the urea suction pipe in urea storage tank. The study includes the change of liquid volume fraction, temperature profiles and a influence of natural convection by using the commercial software STAR-CCM+(v7.06). The accuracy of the numerical analysis is estimated by comparisons with experimental data. After validation, a numerical analysis for freezing urea is conducted with four different heating power. From the results, it was found that relation of velocity of phase interface and amount of melting urea by increasing heating power in a container. There is also a difference in trend between velocity of phase interface and amounts of melting urea because of effect of natural convection.

• 대한수의학회지
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• 제56권2호
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• pp.85-89
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• 2016

We tested a set of conditions for obtaining optimal tissue quality in preparation for histology in samples of mouse brain. C57BL/6J mice were sacrificed and perfused with 4% paraformaldehyde, after which the brains were removed and dehydrated in 30% sucrose solution. The brains were then divided into four groups according to freezing temperature and usage of optimal cutting temperature (OCT) compound. Next, we stained the sectioned brain tissues with Harris hematoxylin and eosin Y and immunohistochemistry was performed for doublecortin. The best quality tissue was obtained at $-25^{\circ}C$ and by not embedding with the OCT compound. When frozen at $-25^{\circ}C$, the embedded tissue was significantly damaged by crystals, while at $-80^{\circ}C$ there were no meaningful differences between qualities of embedded- and non-embedded tissues. Overall, we identified a set of conditions to obtain quality frozen brain sections. Our developed protocol will help resolve matters associated with damage caused to sectioned brain tissue by crystal formation during freezing.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2005년도 연구개발 발표회 논문집
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• pp.405-412
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• 2005

Numerical and experimental investigations were conducted to assess the aerodynamic performance of several centrifugal compressors. In order to impose an appropriate physics at the interface between impeller and vaned diffuser numerically, two different techniques, frozen rotor and stage models, were applied and the simulation results were compared with the corresponding prototype test data. An equivalent sand-grain roughness height was utilized in the present computational study to consider a relative surface roughness effect on the stage performance simulated. From a series of investigations, it was found that the stage model is more suitable than the frozen rotor scheme for the steady interactions between impeller and diffuser in turbocompressor applications. It is supposed that the solution by frozen rotor scheme is inclined to overrate the non-uniformity of the flow fields. The predicted aerodynamic performance accounting for surface roughness effect shows favorable agreement with experimental data. Simulations based on the aerodynamically smooth surface assumption tend to overestimate the stage performance.

• 한국가축번식학회지
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• 제16권3호
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• pp.217-224
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• 1992

These studies were carried out ot investigate on the transferred embryo development following ultrarapid frozen for 8-cell and morula of in vitro fertilization mouse embryos. The post-thaw embryo survival was evaluated and compared by cell stage of embryos and by equilibration time before ultrarapid freezing. The results obatined were summerized as follows: 1. The effects of equilibration time of 3 vs. 6 minutes before ultrarapid freezing and after thawing on the morphological survival and the viability of 8-cell and morulas embryos were not significant. 2. When the ultrarapid frozen-thawed 32 eight-cell and 33 morula embryos, and 30 fresh blastocysts were transferred to pseudopregnant recipient mice, the number of normal offsprings produced were 9(28.1%), 14(42.4%) and 18(60.0%), respectively. From the above resutls, it was concluded that the optimal conditions of pH osmolality of the media for mouse IVF and embryo culture, and the period of sperm preincubation might be 7.1, 310 mOsm and 120 min., respectively,a nd somewhat high conception rate might be resulted from transfer of frozen embryos of morula stage and fresh embryos of blastocyst stage.

• 한국세라믹학회지
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• 제53권3호
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• pp.325-331
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• 2016

Anatase particles of titanium dioxide were prepared from $TiCl_4$ aqueous solution by using an electro-dialysis [ED] process. For the preparation of an aqueous solution of $TiCl_4$ precipitates, $TiCl_4$ liquid frozen in ice was transferred to a neck flask and then hydrolyzed using deionized [DI] $H_2O$. During the hydrolysis of the $TiCl_4$ solution at $0^{\circ}C$, a slurry solution of $TiOCl_2$ was obtained and the color changed from red to orange. The ED process was applied for the removal of chlorine content in the slurry solution. Two kinds of hydrolyzed slurry solution with lower [$Ti^{4+}$] and higher [$Ti^{4+}$] were sampled and the ED process was applied for the samples according to the removal time of [$Cl^-$]. With de-chlorination, the solution status changed from sol to gel and the color quickly changed to blue. Finally, white crystalline powders were formed and the phase was confirmed by XRD to be anatase crystallites. The morphology of the hydrous titania particles in the solution was observed by FE-SEM. The hydrous titania particles were nano-crystalline, and easily coagulated with drying.

• Parasites, Hosts and Diseases
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• 제28권4호
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• pp.241-252
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• 1990

장포자충(Thelohanellus kitauei) 포자의 극사탈출 여부를 생사 각정 기준으로 하여 물리 화학적 요인이 포자의 활성 및 생존에 미치는 영향에 대하여 관찰하였다. 신선 포자를 0.45% 및 0.9% 생리식염수와 증류수에 현학시켜 $5^{\circ}C$ 또는 $28^{\circ}C$에 단기간 보존하면 3일까지, Tyrode액에 철 탁시켜 $-70^{\circ}C$에 단기간 냉동 보존하면 8일까지 극사탈출률이 상승하였다. 신선 포자를 0,45%생리 식염수에 현탁시켜 $5^{\circ}C$에 장기간 보존하면 1,270일간 생존할 수 있을 것으로 추정되며, 증류수에 현탁시켜 $28^{\circ}C$에 보존하면 152일간 밖에 생존하지 않으나, Tyrode액에 현탁시켜 $-70^{\circ}C$에 법통 보존하면 750일 후에도 냉동 초기와 거의 같은 패턴으로 생존하는 것으로 나타났다. 한편, 신선 효 자를 Tyrode액에 현탁, 냉동시킨 다음 $5^{\circ}C$의 조건 하에서 해동시킬 때 포자의 극사설출률이 가잔 높았다. 냉동 후 해동 포자에 열을 가하면 냉동기간이 길수록 극사탈출률이 약간 높아지는 경향이었으며 180일간 냉동례에 있어서 포자가 전부 사멸하는 한계점은 대체적으로 $60^{\circ}C$ 78.5시간, $70^{\circ}C$ 23.4시 간, $80^{\circ}C$ 189.1분 또는 $90^{\circ}C$ 10.5분이었다. 냉동 포자의 해동 후 사멸에 요하는 대체적인 기간도 냉동기간이 길수록 길며, 그 한계점은 20일간 냉동시 17.4일, 100일간 냉동 시 33.2일, 400일간 냉동시 37.8일이었다. 냉동 포자를 해동 후 자연건조시키면 냉동시간이 길수록 포자의 사멸에 요 하는 대체적인 기간도 길며, 그 한계점은 540일간 냉동시 23.5일, 160일간 냉동시 21.0일, 20일간 냉동시 14.4일이었다. 한편, 냉동 후 해동 포자에 l0W 자외선등을 조사하면 냉동시간이 길수록 빨리 사멸하며, 그 한계점은 100일간 냉동시 26.0시간, 300일간 냉동시 21.9시간, 540일간 냉동시 13.9시간이었다. 각종 소독제(1,000 ppm)가 200일간 냉동 후 해동 포자를 사멸시키는데 필요한 시 간은 산화칼슘 5.2분, 과망간뜬칼륨 10.4분, 말라카이트그린 27.8분, 포르말린 14.3시간의 순이었다. 그리고, 각종 항원충 및 둔진균제 중에서 ketoconazole, metronidazole, dapsone의 순으로 일시적인 극사탈출 억제 효과가 인정되었다. 이상의 실험 결과로 미루어 보아 장포자충증의 감염을 예방하기 위해서는 현시점에 있어서 양어장의 바닥을 콘크리트로 축달하여 완전 건조시킨 다음 산화칼슘을 철포하고 태양광선을 수일 간에 걸쳐 조사시키는 방법 밖에 없는 것으로 생각된다.

• 한국수정란이식학회지
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• 제11권1호
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• pp.41-50
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• 1996

This experiment was carried out to investigate the ovarian responses of the ovulation point, ovarian weight and size, the number of ovarian follicles and collected embryos, and to study the effects of the developmental stages (oocytes, 2-4 cell. 8-16 cell and morulae), additional levels of Ficoll (0, 15, 30%) on the survival rate (FDA-test) of rat embryos frozen in vitrification solution (20% glycerol + 10% ethylene glycol + 10% sucrose). Sunanarized results was as follows; 1. The mean ovulation point per head was 7, and the weight of ovaries was 0.03g. The size of ovary was 5.9 mm(L) and 4.6 mm(W), and the number of ovarian follicles over and below 2 mm was 4.7 and 8.7, respectively. The number of the collected embryos per head was 5.5 (79%). 2. 2. The FDA score of embryos frozen in 20 G 10 E 10 S without Ficoll was 2.8 (oocyte), 2.6 (2-4 cell), 3.9 (8-16 cell) and 3.6 (morula), respectively. However, there were no significant differences among treatments. 3. The FDA score of embryos frozen in 20 G 10 E 10 S with 15% Ficoll was 3.4 (oocyte), 4.0 (2-4 cell), 4.7 (8-16 cell) and 4.8 (morulae), respectively (P>0.05). 4. The FDA score of embryos frozen in 20 G 10 E 10 S with 30 % Ficoll was 3.7 (oocyte), 3.2 (2-4 cell), 4.4 (8-16 cell) and 4.4 (morulae), respectively (P>0.05). 5. As shown in the above results, the higher survival rate was obtained in the treatment of 15% Ficoll than that of 30%. And the survival rate (FDA-test)of the oocytes and 2-4 cell stages of the rat embryos was lower than that of 8~16 cell and morulae stages. It was considered that 8-16 cell and morulae could be available for the successful freezing by vitrification of rat embryos with 15% Ficoll except for oocytes.

• 만화애니메이션 연구
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• 통권37호
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• pp.197-219
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• 2014

디즈니 애니메이션 <겨울왕국>이 한국에서 개봉된 애니메이션 사상 첫 천만 관객을 동원했다. 겨울왕국은 주제곡 'let it go'의 열풍과 엘사, 안나, 울라프의 캐릭터 상품들을 비롯해 각종 신드롬까지 낳고 있다. 그렇다면 겨울왕국이 어떤 의미를 생성하고 있기에 이토록 한국에서 선풍적인 인기를 끌었는지를 생각해 볼 필요가 있다. 이 연구는 겨울왕국이 관객에게 전달하고자 하는 가치와 겨울왕국이 생성하는 의미는 무엇인지를 그레마스의 행위소 모형과 기호사각형을 이용하여 살펴보고자 한다. 행위소 모형으로 <겨울왕국>의 안나와 엘사를 분석한 결과, 안나는 엘사와의 관계회복과 아렌델의 여름을 되찾기를 욕망한다. 이것은 엘사에 대한 사랑과 아렌델사람들을 위한 사랑으로 말하여질 수 있다. 한편, 엘사는 자신의 설빙능력으로 인해 스스로를 가두기는 하지만 항상 자유를 갈망한다. 즉 엘사는 자신의 설빙능력을 제어하는 방법을 알아내 자신의 설빙능력으로 자유로워지를 욕망하는 것이다. 이러한 안나와 엘사의 욕망은 진실한 사랑의 행동을 통해 획득되어지며, <겨울왕국>에서 모든 갈등의 해결책은 진실한 사랑의 행동이다. 기호사각형으로 <겨울왕국>의 의미를 분석한 결과, <겨울왕국>은 현재의 비정상적인 삶을 과거의 정상적인 삶으로 바꾸고자 하는 과거지향적인 가치를 창출한다. 현재의 삶-한 여름에 추운 겨울이 찾아오고, 자매간의 소통이 단절되며, 비정상의 상태를 의도적으로 이용하여 자신의 이익을 취하려는 사람들-을 과거의 돈독했던 자매간의 우애와 순리적인 계절인 아렌델의 여름으로 바꾸고자 하는 것이다. <겨울왕국>에서 말하고자 하는 과거를 지향하는 가치는 21세기를 살아가는 우리의 현실과 비슷하다. 들었어도 믿기 어려운 소식들, 불안한 정세 등이 난무하는 현실에서 어렵고 힘들어도 정과 희망이 넘쳐났던 과거의 삶으로 돌아가고 싶은 우리의 정서와 맞물렸기 때문에 국내에서 <겨울왕국>이 승승장구하지 않았나 싶다.

• 한국수정란이식학회지
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• 제9권1호
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• pp.7-14
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• 1994

The present experiments on cryopreservation were designed to examine the effects of solution toxicity, equilibration time and cell stages on the post-thaw survival of bovine IVF embryos. The oocytes were matured in vitro(IVM) for 24 hrs. in TCM-199 supplemented with 35 $\mu$g /ml FSH, 10 $\mu$g /ml LH, 1 $\mu$g /ml estradiol-17$\beta$ and granulosa cells at 39$^{\circ}C$ under 5% $CO_2$ in air. They were fertilized in vitro(IVF) by epididymal spermatozoa treated with heparin for 24 hrs., and then the zygotes were co-cultured in vitro(IVC) with bovine oviductal epithelial cells for 7 to 9 days. The bovine IVF embryos were exposed to the EFS solution in one step at room temperature, kept in the EFS solution during different period for toxicity test, vitrified in liquid nitrogen, and thawed rapidly. 1. after the bovine blastocysts were exposed to EFS solution for 2 min. at room temperature and then they were washed in 0.5 M sucrose solution and TCM-199, they were cultured to examined cryoprotectant induced injury during exposure, Most of the embryos(95.0%) developed to reexpanded blastocoels. However, when the exposure time was extended to 5 and 10 min, these development rates dropped dramatically in 5 min. (69.5%) and 10 min. (47.4%), respectively, 2. When the bovine IVF embryos were vitrified in EFS solution after the equilibration for 1 and 2 min. exposure, The embryos to have reexpanded blastocoels following thawing, washing and culture processes were found to he 82.6 and 73.9%, respectively. However, when the exposure time was extended to 3 min, this survival rate dropped to 18.2%. The optimal time for equilibration of bovine IVF blastocysts in EFS solution seemed to he 1~2 min. 3. When the bovine IVF embryos were equilibrated for 1 min. the significantly (P<0. 05) higher post-thaw survival rates were obtained from the embryos of blastocyst stage(81.3%) than morulae stage(5. 1%). The optimal cell stage for viterification with EFS solution proven to he blastocyst stage in bovine IVF embryos. 4. The number of blastomeres of blastocyst stage was examined with nuclear staining with Hoechst 33342 during 7 to 9 days post-insemination. The cell counts of frozen bovine IVF embryos were found significantly(P$\geq$7.5 and those of the fresh embryos 76.6$\geq$7. 1, which were cultured in the sarne period and conditions as frozen embryos.

• 한국식품과학회지
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• 제50권2호
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• pp.186-190
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• 2018

본 연구는 냉동 콩나물비빔밥 제품의 공정 최적화를 위해 수행되었고, 각 공정에서 공정변수에 따른 콩나물의 전단력, 배축직경, 중량감소 등과 같은 물리적 특성의 변화를 살펴보았다. 또한 각 공정마다 유효한 공정변수들을 조합하여 최종 냉동 후 조리에 의한 콩나물의 물리적 특성에 미치는 영향을 살펴보았다. 콩나물 데치기 공정에서, 처리시간의 감소와 당수 사용은 배축직경 수축과 중량감소를 줄이는 효과가 있었다. 조미 배합에서는 설탕의 사용이 소금과 설탕 혼합 사용보다 배축직경이 크고 중량감소가 적게 나타났다. 하지만 이와 같은 단위공정 단일변수적용에 의해서는 콩나물비빔밥 냉동 후 조리한 콩나물에서 배축직경 감소와 중량감소 완화의 유의적 효과는 관찰되지 않았다. 대조구 공정은 열수 데치기, 염과 설탕의 혼합 조미, 취반미 비빔형태로 진행되었고, 공정변수 조합은 당수 데치기, 설탕 조미, 취반미 비빔 또는 토핑형태로 진행되었다. 조합 공정은 대조구 공정 보다 냉동 후 조리콩나물의 유의적으로 높은 전단력과 배축직경, 낮은 중량감소를 유도하였다(p<0.05). 결론적으로, 각 공정에서 유의적 효과를 도출한 공정변수의 조합은 콩나물 비빔밥 냉동 후 조리 시 콩나물 물리적 특성을 개선시킬 수 있을 것으로 사료되었다.