• 공업화학
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• 제33권1호
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• pp.11-16
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• 2022

금속유기골격체(metal-organic frameworks, MOFs)는 나노사이즈의 기공을 가진 다공성 물질로, 금속이온과 유기리간드의 종류에 따라 기체흡착도 및 기공크기의 조절이 가능하다. 이러한 장점을 이용하여, 기체 포집 및 분리, 그리고 기체센서분야에서 금속유기골격체에 대한 연구가 많이 이루어지고 있다. 신속하고, 정량적인 기체 흡탈착 분석을 위해서는, 센서 표면에 균일한 필름 형태의 다양한 MOF 구조체를 형성해야 한다. 본 총설논문에서는 양극산화알루미늄, 산화아연 나노막대, 구리 박막으로부터 직접합성법을 이용하여 각각 MIL-53 (Al), ZIF-8, Cu-BDC와 같은 MOF를 마이크로진동자 센서 표면에 균일하게 합성하는 방법에 대해 정리하였다. 또한, 대표적인 마이크로진동자인 수정진동자미세저울과 마이크로캔틸레버의 작동원리와 금속유기골격체에 기체흡착 시 변하는 신호해석에 대한 내용을 다룬다. 이를 통해, 마이크로진동자 기반 금속유기골격체의 기체 흡탈착 분석에 대한 이해를 높이고자 한다.

• 한국재료학회지
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• 제31권8호
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• pp.465-470
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• 2021

Deuterium is a crucial clean energy source required for nuclear fusion and is a future resource needed in various industries and scientific fields. However, it is not easy to enrich deuterium because the proportion of deuterium in the hydrogen mixture is scarce, at approximately 0.016 %. Furthermore, the physical and chemical properties of the hydrogen mixture and deuterium are very similar. Therefore, the efficient separation of deuterium from hydrogen mixtures is often a significant challenge when using modern separation technologies. Recently, to effectively separate deuterium, studies utilizing the 'Kinetic Quantum Sieving Effect (KQS)' of porous materials are increasing. Therefore, in this review, two different strategies have been discussed for improving KQS efficiency for hydrogen isotope separation performance using nanoporous materials. One is the gating effect, which precisely controls the aperture locally by adjusting the temperature and pressure. The second is the breathing phenomenon, utilizing the volume change of the structure from closed system to open system. It has been reported that efficient hydrogen isotope separation is possible using these two methods, and each of these effects is described in detail in this review. In addition, a specific-isotope responsive system (e.g., 2nd breathing effect in MIL-53) has recently been discovered and is described here as well.

• 한국항해항만학회지
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• 제26권3호
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• pp.289-294
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• 2002

본 논문에서는 디지털 TV 중계기용 고출력 광대역의 3-Way 전력결합기를 설계.제작하였다. 대역폭 증가와 고출력을 동시에 이루기 위하여 Wilkinson 형태의 전력분배기를 채택하였다. 우선 Wilkinson 전력분배기를 균등(1 : 1) 및 비균등(2 : 1) 분배시켜, 동위상 4 포트 전력결합기를 시뮬레이션 하였다. 시뮬레이션 결과에 따라서 두께 120 mil인 유전체 기판을 사용하여 제작된 전력결합기는 디지털 TV 중계기 주파수 470~806 MHz 대역에서 삽입손실 -6.53dB 이하, 반사계수 -13dB 이하, 포트 간 분리도 -15 dB 이하, 출력 포트 간 위상차가 13$^{\circ}$이하의 특성을 보였다. 새롭게 만든 전력결합기는 회로에서의 고 임피던스로 인한 마이크로스트립 선로 폭의 한계와 고출력의 경우 선로간의 상호작용으로 인한 전력의 손실 및 협대역의 문제를 동시에 개선이 가능함을 알 수 있었다. 나아가서, 제작된 3-Way 결합기의 삽입손실, 반사계수, 포트간의 분리도 및 위상차가 디지털 TV 중계주파수 470~806 MHz에서 양호한 특성을 나타내는 것을 확인함으로써 고출력 및 광대역화가 실현가능하다는 것을 알 수 있었다.

• Reproductive and Developmental Biology
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• 제31권2호
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• pp.61-69
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• 2007

This study was designed to evaluate effects of BSA, PVA, gonadotropins and follicle shell during IVM of porcine oocytes and subsequent development to the blastocyst stage after IVF. Cumulus oocyte complexes (COCs) were cultured in TCM-199 media containing 4 mg/ml BSA and 1 mg/ml PVA during IVM for 44 hr. To compare the effect of gonadotropins on oocyte maturation, COCs were cultured with FSH+LH, FSH, LH and FSH-LH-free media during IVM. respectively. Also, different number of follicle shells (0, 2, 4 and 6) was used to examine whether the presence of follicle shell in culture medium affects oocyte maturation. The percentages of fertilization and blastocyst formation, respectively, were higher in the medium containing the PVA (49.0 and 17.9%) than those containing the BSA (40.0 and 12.2%). Significantly higher rates of Mil oocytes were in the presence of FSH+LH and FSH (88.6 and 85.1 %) compared to other treatments (64.0 and 53.4% at LH and FSH-LH-free media). Co-culture with inverted follicle shells in 2 ml maturation medium enhanced the developmental competence of porcine oocytes. In conclusion, PVA could be used as a macromolecules instead of BSA, and FSH and follicle shell played important roles in maturation of porcine oocytes.

• 한국연초학회지
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• 제13권2호
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• pp.5-20
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• 1991

For the quality enhancement of harvested-year leaf tobacco to the quality of 2-year naturally aged leaf tobacco, cellulose and nicotine degradative bacteria were isolated and identified. Effects of artificial fermentation treated cellulase and nicotine degradative bacteria on the quality of leaf tobacco were investigated from the chemical and sensory points of view. 1, Changes in chemical composition of leaf tobacco resulted from the addition of cellulase extracted from Cellulomonas sp. [3ml(${\mu}{\textrm}{m}$ D-glucose/ml. mil-1) of enzymes solution 11009 of leaf tobacco] and nicotine degradative bacteria, Pseudomonas sp. 2ml(IX109 cells$\div$ 100g of leaf tobacco), and subsequently fermented at 40${\mu}{\textrm}{m}$$^{\circ}C$, 65% R. H. for 40 days are as follows : 1) Content of crude fiber decreased 12% It took 9 min, 53 sec. to reach full combustion in control group but took only 7 min. 47 sec. in the treated group, taking almost equal time to 2-year naturally aged leaf tobacco(7 min. 35sec.). 2) Light intensity of control group was 60.96% with bright lemon color but that of treated leaf tobacco accounted for 47.69 with orange to dark brown color series, which was almost equal to the value, 45.69, of 2-year naturally aged leaf tobacco. 3) Linoleic acid, serving mild taste among organic acids, amounted to 1.llmg/g in control group but increased to 1.35m9/9 in the treated leaf tobacco, identical to the content(1.35mg/g) of 2-year naturally aged leaf tobacco. 4) Content of solanone, on of the typical leaf tobacco flavor compounds, accounted for 2.95% in control group but increased to 2.87% in treated group. 5) Methyl furan, useful flavor compound in smoke composition, accounted for 17.6$\mu\textrm{g}$/cig. in control group but increased to 25.9$\mu\textrm{g}$/cig. in treated group. However, acroleine decreased from 69.3$\mu\textrm{g}$/cig. in control group to 58.6$\mu\textrm{g}$/cig. in treated group 2. In sonsory test, mild taste evaluation of control group scored 5.47 and treated group 7.93 which was evaluted almost equal to the value(8.00) of 2-year naturally aged leaf tobacco. Aroma evaluation of control group scored 5.60, treated group 8.20, and 2-year naturally aged leaf tobacco 8.33. In addition, total harmony taste of control group showed 5.67, treated group 8.07 (p<0.01), and 2-year naturally aged leaf tobacco 8.00. From these results, it can be said that quality of treated leaf tobacco is not inferior to that 2-year naturally aged leaf tobacco.

• Journal of Chest Surgery
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• 제57권4호
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• pp.371-379
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• 2024

Background: Sutureless valves are widely used in aortic valve replacement surgery, with Perceval valves and Intuity valves being particularly prominent. However, concerns have been raised about postoperative thrombocytopenia with Perceval valves (Corcym, UK). We conducted a comparative analysis with the Intuity valve (Edwards Lifesciences, USA), and assessed how thrombocytopenia affected patient and transfusion outcomes. Methods: Among 595 patients who underwent aortic valve replacement from June 2016 to March 2023, sutureless valves were used in 53 (Perceval: n=23; Intuity: n=30). Platelet counts were monitored during hospitalization and outpatient visits. Daily platelet count changes were compared between groups, and the results from patients who underwent procedures using Carpentier Edwards Perimount Magna valves were used as a reference group. Results: Compared to the Intuity group, the Perceval group showed a significantly higher amount of platelet transfusion (5.48±1.64 packs vs. 0.60±0.44 packs, p=0.008). During the postoperative period, severe thrombocytopenia (<50,000/μL) was significantly more prevalent in the Perceval group (56.5%, n=13) than in the Intuity group (6.7%, n=2). After initial postoperative depletion, daily platelet counts increased, with significant differences observed in the extent of improvement between the Perceval and Intuity groups (p<0.001). However, there was no significant difference in early mortality or the incidence of neurological complications between the 2 groups. Conclusion: The severity of postoperative thrombocytopenia differed significantly between the Perceval and Intuity valves. The Perceval group showed a significantly higher prevalence of severe thrombocytopenia and higher platelet transfusion volumes. However, thrombocytopenia gradually recovered during the postoperative period in both groups, and the early outcomes were similar in both groups.

• Journal of Chest Surgery
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• 제30권10호
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• pp.973-978
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• 1997

본원에서는 1991년 1월부터 1995년 12월까지 64명의 환자가 인공심장판막의 이상으로 재치환술을 받았다. 주로 판막자체의 기능부전으로 53명(82.8%)이 재수술을 받았으며, 나머지는 판막혈전증으로 6명(9.4%), 판막 주위의 누출로 3명(4.7%), 심내막염으로 2명(3.6%)이 재수술을 받았다. 판막자체의 기능부전(40명, 75%)과 판 막혈전증(4명, 67%)은 주로 승모판막에서 호발하였으며, 판막 주위의 누출(3명, 100%)은 대동맥판막에서 발 생하였다. 가장 긴 적출기간 첫번째 인공심장판막 치환술을 받은 후로부터 재수술을 받기까지의 기간 은 판막자체의 기능부전으로 평균 107.4$\pm$24.6개월이었고, 판막혈전증을 동반한 심내막염(1명)에서 1개월로 가 장 짧았다. 대동맥판막과 승모판막에서 평균 적출기간은 각각 109.5$\pm$10.4, 109.2$\pm$10.7개월이었다. 전체 병원 사망율은 9.38%(6/64), 저심박출증이 4명으로 가장 많았고 기타 출혈 및 중추신경계 손상이 각각 1례씩 있었 다. 독립적인 술후 위 험 인자로는, 술전 MilD class W(P=0.011), 응급 수술(P=0.011), 심내막염(P=0.001) 들이 의미가 있었으며 기타 나이, 성별, 대동맥차단시간, 적출기간, 중복 판막 치환술 2차 재치환술, 판막위치 등 은 술후 위험 인자로서 통계학적 의미가 없었다. 평균 추적기간은 28.8$\pm$17.8개월이었고, 3년 누적 생존율은 92.0$\pm$6.2%, 2년 무합병 생존율은 84.3$\pm$6.1%였다. 인공심장판막 실패로 인하여 재수술을 받아야할 환자에 있어서, 위에서 언급한 위험 인자 술전 miBs class W, 응급 수술, 심내막염의 관점에서 술전 상태를 잘 조절하여 재수술을 시행하여야 한다. 가능한 다른 위험 인자에 대해서도 추후 연구가 필요하다.

• Journal of Biosystems Engineering
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• 제3권1호
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• pp.47-63
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• 1978

This study was conducted to obtain a basic information necessary to assess present rice milling technology in Korea The profiles for milling plants was analyzed by survey work.For the private custom-work mills, which process about 80 percent of domestic rice consumption ,their actual milling test for the identical samples as used for filed mills was conducted. Two rice varieties Japonica and Tongil-type were associated with the experiments. The results are summarized as follows: 1. Analyses for private custom-work mills showed their general aspects as; about 91 percent of the mills belonged to an individual owner ship ; more than 93 percent of the mills was established earlier than 1950 ; about 80 percent of the mills was powered with electric motor; mills having less than two employees were about 75 percent; about 45 percent of the mills provided for warehouse in storing customers cereal grains. 2. The polishers installed in 1,255mills within the surveyed area (7 counties) have been supplied by 44 different domestic manufacturers ;in but about 60 percent of which was supplied by 6major manufacturers. The polishers could be classified into two categories in terms of principles of their polishing actions ;jet-pearler and friction types. About 51 percent of the mills was equipped with the former which has been recognized as giving greater milling recovery than the friction types. 3. Reason for owners of private mills to supplement new machines was due mainly to pgrading their mills to meet the requirements that established by the Government. However, about 60 percent of the mill owners intended to replace with new pearler by their own needs to meet with new high yielding varieties. 4. Processing systems of each previate rice mills surveyed could be classified into three categories, depending upon whether the systems posessed such components as precleaner and paddy separator or not. Only 36.7 percent of mills was installed with both precleanr ad paddy seperrator, 5.0 percent of mills did have neither percleaner nor paddy seperator, and rest of them equipped only one of the two. Hence,it is needed for about 63% of rice miils to be supplemented with these basic facilities to meet with the requirements for the standaized system. 5. Actual milling capacity measured at each field rice mills was shown a wide variation, having range from about 190 to 1,210 kg/hr. The percentages of mills classified according to daily milling capacity based on this hourly capacity were 24.3% for the capacity less than 3 M/T a day; 20.0% for 3-4 M/T; 15.6% for 4-5 M/T; 6.7% for 5-6 M/T; 22.3% for 6-7 M/T; and 11.0% for more than 7 M/T a day. 6. Actual amount of rice processed was about 310 M/T a year in average. About 42% of total milled rice was processed during October to Decembear, which formed a peak demand period for rice mills. The amount of rice milled during January to May was relatively small, but it had still a large amount compared to that during June to September. 7. Utilization rate of milling facility, i. e., percentage of the actual amount of milled rice to the capacity of rice mills, was about 18% on the year round average, about 41% in the peak demand season, and about 10% during June to September. Average number of operating days for mills surveyed was about 250 days a year, and about 21 days a month. 8. Moisture contents of paddy at the time of field mill tests were ranged 14.5% to 19.5% for both Japonica and Tong-i] varieties, majority of paddy grains having moisture level much higher than 1530. To aviod potential reduction of milling recovery while milling and deterioration of milled rice while storage due to these high grain mJisture contents, it may be very important for farmers holding rice to dry by an artificial drying method. 9. Milling recovery of JapJnica varieties in rice mills was 75.0% in average and it was widely ranged from 69.0% to 78.0 % according to mills. Potential increase in milJing recovery of Japonica variety with improvement of mill facilities was estimated to about 1.9%. On the other hand, milling recovery of Tong-il varieties in the field mill tests was 69.8% in average and it ranged from 62% to 77 %, which is much wider than that of Japonica varieties. It is noticed that the average milling recovery of Tong-il variety of 69.8% was much less than that of the Japonica-type. It was estimated th3.t up to about 5.0% of milling recovery for Tong-il variety could be improved by improving the present lo'.ver graded milling technology. 10. Head rice recoveries, as a factor of representing the quality of commercial goods, of Japonica and Tong-il varieties were 65.9% and 53.8% in average, and they were widely ranged from 52% to 73% and from 44% to 65% , respectively. It was assessed that head rice recovery of Japonica varieties can be improved up 3.3% and that of Tong-il varieties by 7.0% by improving mill components and systems.

• 한국문헌정보학회지
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• 제17권
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• pp.11-47
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• 1989

This study intends to examine the background and the procedure of the carving of the tablets of the second edition of Dae-Jang-Mock­Lock(재조대장목록). the time and the route of the moving of the tablets. into Haein-sa, and the contents and the system of it. This study is mainly based on the second edition of Dae-Jang-Mock-Lock. But the other closely related materials such as restored first. edition of the Dae- Jang-Mock-Lock, Koryo Sin-Jo-Dae-Jang-Byeol-Lock (고려신조대장교정별록). Kae-Won-Seok-Kyo-Lock (개원석교록). Sok-Kae­Won-Seok-Kyo-Lock (속개원석교록). Jeong-Won-Sin-Jeong-Seok-Kyo­Lock(정원신정석교록), Sok-Jeong-Won-Seok-Kyo-Lock(속정원석교록), Dea-Jung-Sang-Bu-Beob-Bo-Lock(대중상부법보록), and Kyeong-Woo-Sin-Su-Beob-Bo-Lock(경우신수법보록), are also analysed and closely examined. The results of this study can be summarized as follows: 1. The second edition of Tripitaka Koreana(고려대장경) was carved for the purpose of defending the country from Mongolia with the power of Buddhism, after the tablets of the first edition in Buin-sa(부이사) was destroyed by fire. 2. In 1236. Dae-Jang-Do-Gam(대장도감) was established, and the preparation for the recarving of the tablets such as comparison between the content, of the first edition of Tripitalk Koreana, Gal-Bo-Chik-Pan-Dae­Jang-Kyeong and Kitan Dae- Jang-Kyeong, transcription of the original copy and the preparation of the wood, etc. was started. 3. In 1237 after the announcement of Dae-Jang-Gyeong-Gak-Pan-Gun­Sin-Gi-Go-Mun(대장경핵판군신석고문), the carving was started on a full scale. And seven years later (1243), Bun-Sa-Dae-Jang-Do-Gam(분사대장도감) was established in the area of the South to expand and hasten the work. And a large number of the tablets were carved in there. 4. It took 16 years to carve the main text and the supplements of the second edition of Tripitaka Koreana, the main text being carved from 1237 to 1248 and the supplement from 1244 to 1251. 5. It can be supposed that the tablets of the second edition of Tripitaka Koreana, stored in Seon-Won-Sa(선원사), Kang-Wha(강화), for about 140 years, was moved to Ji-Cheon-Sa(지천사), Yong-San(용산), and to Hae-In-Sa(해인사) again, through the west and the south sea and Jang-Gyeong-Po(장경포), Go-Ryeong(고령), in the autumn of the same year. 6. The second edition of Tripitaka Koreana was carved mainly based on the first edition, comparing with Gae-Bo-Chik-Pan-Dae-Jang-Kyeong(개보판대장경) and Kitan Dae-Jang-Kyeong(계단대장경). And the second edition of Dae-Jang-Mock-Lock also compiled mainly based on the first edition with the reference to Kae-Won-Seok-Kyo-Lock and Sok-Jeong-Won-Seok-Kyo-Lock. 7. Comparing with the first edition of Dae-Jang-Mock-Lock, in the second edition 7 items of 9 volumes of Kitan text such as Weol-Deung­Sam-Mae-Gyeong-Ron(월증삼매경론) are added and 3 items of 60 volumes such as Dae-Jong-Ji-Hyeon-Mun-Ron(대종지현문논) are substituted into others from Cheon chest(천함) to Kaeng chest(경함), and 92 items of 601 volumes such as Beob-Won-Ju-Rim-Jeon(법원주임전) are added after Kaeng chest. And 4 items of 50 volumes such as Yuk-Ja-Sin-Ju-Wang-Kyeong(육자신주왕경) are ommitted in the second edition. 8. Comparing with Kae-Won-Seok-Kyo-Lock, Cheon chest to Young chest (영함) of the second edition is compiled according to Ib-Jang-Lock(입장록) of Kae-Won-Seok-Kyo-Lock. But 15 items of 43 vol­umes such as Bul-Seol-Ban-Ju-Sam-Mae-Kyeong(불설반주삼매경) are ;added and 7 items of 35 volumes such as Dae-Bang-Deung-Dae-Jib-Il­Jang-Kyeong(대방등대집일장경) are ommitted. 9. Comparing with Sok-Jeong-Won-Seok-Kyo-Lock, 3 items of the 47 volumes (or 49 volumes) are ommitted and 4 items of 96 volumes are ;added in Caek chest(책함) to Mil chest(밀함) of the second edition. But the items are arranged in the same order. 10. Comparing with Dae- Jung-Sang-Bo-Beob-Bo-Lock, the arrangement of the second edition is entirely different from it. But 170 items of 329 volumes are also included in Doo chest(두함) to Kyeong chest(경함) of the second edition, and 53 items of 125 volumes in Jun chest(존함) to Jeong chest(정함). And 10 items of 108 volumes in the last part of Dae-Jung-Sang-Bo-Beob-Bo-Lock are ommitted and 3 items of 131 volumes such as Beob-Won-Ju-Rim-Jeon(법원주임전) are added in the second edition. 11. Comparing with Kyeong-Woo-Sin-Su-Beob-Bo-Lock, all of the items (21 items of 161 volumes) are included in the second edition without ;any classificatory system. And 22 items of 172 volumes in the Seong­Hyeon-Jib-Jeon(성현집전) part such as Myo-Gak-Bi-Cheon(묘각비전) are ommitted. 12. The last part of the second edition, Joo chest(주함) to Dong chest (동함), includes 14 items of 237 volumes. But these items cannot be found in any other former Buddhist catalog. So it might be supposed as the Kitan texts. 13. Besides including almost all items in Kae-Won-Seok-Kyo-Lock and all items in Sok-Jeong-Won-Seok-Kyo-Lock, Dae-Jung-Sang-Bo­Beob-Bo-Lock, and Kyeong-Woo-Sin-Su-Beob-Bo-Lock, the second edition of Dae-Jang-Mock-Lock includes more items, at least 20 items of about 300 volumes of Kitan Tripitaka and 15 items of 43 volumes of traditional Korean Tripitake that cannot be found any others. Therefore, Tripitaka Koreana can be said as a comprehensive Tripitaka covering all items of Tripitakas translated in Chinese character.