회분식 발효에서의 전기투석에 의한 젖산의 동시분리

이은교,장용근,장호남,김인호 한국산업미생물학회 1995 한국미생물·생명공학회지 Vol.23 No.5

전기투석속도에 영향을 주는 인자로서 전압, 젖산농도, 온도, 젖산염 종류, pH등을 살펴보았다. 전압은 예상대로 전기투석속도에 가장 큰 영향을 주는 인자로 밝혀졌으며, 전압이 높아질수록 전기투석속도가 크게 증가하여 4,6,8 V의 전위차하에서 각각 0.29, 1.81, 4.43 g/h의 평균 전기투석속도를 얻었다. 동일 전압 하에서 source solution 농도가 높아질수록 전기투석속도는 증가하였다. 또한 전기투석실험 말기에 source solution으로부터 침투물 용액으로의 젖산 이동이 두 용액간의 농도차에 의해 제한받는 현상도 관찰되었는데, 이런 현상은 전류에 의한 젖산이온 이동과 농도차에 의한 back-diffusion이 상쇄되기 때문인 것으로 해석되었다. 25℃와 35℃에서의 전기투석실험과에 따르면 10℃ 온도 상승에 대해서 전기투석속도는 약 10% 증가를 보였다. pH를 4.0, 5.0, 6.0로 변화시켜 본 결과, pH 4.0에서의 전기투석속도가 가장 빠르게 나타났고, Na-lactate보다는 NH_4-lactate 형태가 전기투석속도면에서 유리함을 알 수 있었다. 회분식 발효시 전기투석에 의한 in situ 젖산 분리효과를 알아보기 위해 pH 조절만 한 경우, pH 조절없이 전기 투석만 한 경우, pH 조절과 전기투석을 동시에 한 경우 세가지 면에서 살펴보았다. 세가지 경우 중 pH 조절을 하면서 전기투석을 한 발효가 전반적으로 수율이나 생산성 면에서 효과적이었다. 초기 포도당 농도가 50g/l인 경우에는 현저한 차이를 보이지 않았으나, 150g/l인 경우에는 약 1.7배의 생산성 효과를 얻을 수 있었다. Effects of lactate concentration, temperature, counter ions, pH as well as voltage (current) in batch electrodialysis (ED) experiments with a 3-compartment unit were investigated. The applied voltage was found to be the most critical factor as expected. The electrodialysis rate increased with the lactate concentration of the source solution. The amount of lactate transferred was limited by the lactate concentration difference between cathode and permeate compartments. The electrodialysis rate did not heavily depend on temperature change. The electrodialysis rate of NH_4-lactate was faster than that of Na-lactate and both lactates showed the highest electrodialysis rate at a pH of 4.0. A little amount of non-ionic glucose diffused through the anionic membrane to the permeate compartment. To test the effectiveness of the in situ recovery of lactic acid from fermentation broth by ED, three cases of batch culture were carried out; pH control only, ED only, and pH control and ED. The case with both pH control and ED was more efficient than that with pH control only in the aspects of productivity and product yield.

IEEE 802.11 WLANs 환경에서 핫스팟의 혼잡을 분산하는 AP 선택정책

이광교,최창열 江原大學校 産業技術硏究所 2008 産業技術硏究 Vol.28 No.A

A typical AP (Access Point) selection policy is to select an AP based on the received signal strength indicator (RSSI), ignoring its load. If multiple stations are deployed densely at a particular area, a typical AP selection policy will bring about the overall network throughput degradation. This paper proposes a novel AP selection policy taking into consideration not only signal strength of the APs but also AP loads to avoid Hotspot congestion. An expehment on Alinker implementing proposed AP selection policy, demonstrates that the proposed policy achieves close to optimal load balancing and grants the maximum transmission rate to stations in comparison with SSF (Strongest-Signal-First) and LLF (Least-Loaded-First).

濟州道 玄武岩 碎石組骨材를 使用한 콘크리트의 强度에 관한 實驗的 硏究

서일교,양창희 제주대학교 산업기술연구소 1999 尖端技術硏究所論文集 Vol.10 No.2

There are many factors to influence on the physical properties of the concrete, such as the size and shape of aggregates, W/C ratio and the strength of cement, etc. Cheju island is regionally volcanic island. The coarse aggregates to be generally utilized for producing the concrete in Cheju island are the crushed ones of basalt. However, the aggregates are locally different chemical and physical properties and these differences show different properties of concrete. In this study, we investigated the properties of concrete by the utilization of crushed aggregates from two places, Sangchang and Sangga in Cheju island through the test of compressive, tensile, and flexural strength with curing time.

미국의 중국문학 연구동향

柳昌嬌 한국중국어문학회 2000 中國文學 Vol.33 No.-

本文是關于美國的硏究中國文學的動向的槪括介紹. 本文的內容包括兩個部分.第-部分介紹美國大學和硏究所的敎育項目. 大學和硏究所是培養學者的主要搖藍. 本文是以美國的威斯康辛大學東亞語言文學系爲一個例子介紹三個條. (一) 碩士, 博士學位項目的主要特點和師資人員. (二)以現汽漢語敎育爲中心的大學敎育項目和硏究所的主要課程內容. (三)威斯康辛大學的東亞網絡會萃. 這個網絡會葦反映美國硏究中國文學的動向. 第二部分是關于美國的硏究中國文學的主要成果和主要學會及學術雜誌. 美國硏究中國文學的咸果巨大, 所以本文槪括介紹主要的飜譯作家, 飜證作品和在詩歌, 散文, 小說, 獻曲等文學體裁的主要學者及其著書. 美國與硏究中國文學有關的學會及學術雜誌太多. 本文只是簡單地介紹7主要學會和學術雜誌及其主要特點. 美國的硏究中國文學的動向裡突出. 所以不能-言斷之. 但是槪言之, 奮們有五個特點.(一)大學敎育項目 是以嚴格的漢語敎育爲中心. (二)硏究所的主要課程重視活用工具書和硏究方法釜且博大精澤地介紹旣成的硏究及參考文獻. (三)美國的著書中有裡多的硏究文獻及參考文離目錄書及指導叢書, 這些書給美國的硏究中國文學者提供方便. (四)在文學體裁方面, 硏究誇歌, 小說的著書比 戱曲, 散文更豊富. (五)美國硏究中國文學的傾向之-是援用西洋(歐美)的學術方法和文學批評方法進行硏究的. 一般地講, 中國, 臺灣, 日本, 韓國等亞洲的硏究中國文學的學者主要參考亞洲本身的材料及硏究成果. 但是美國的學者除了亞洲硏究成果以外還參考獸美的硏究成果而在這些歐美的硏究咸果裏面正是蘊含着亞洲所不具有的學術方法和批評方法.

위암의 병기결정에 있어서 이중시기 나선식 CT의 유용성

최교창 순천향의학연구소 2001 Journal of Soonchunhyang Medical Science Vol.7 No.1

Purpose: To evaluate the usefulness of two-phase spiral CT in the staging of gastric carcinoma. Materials and Methods: The author preformed two-phase spiral CT in 49 patients with gastric carcinomas surgically and pathologically proven after endoscopic biopsy. CT scans were obtained after ingestion of 800-1000mL of water. In all 49 patients, two-phase spiral CT findings of gastric carcinoma were retrospectively evaluated and correlated with surgical and pathological findings. Results: The author correctly detected 15(83.3%) of 18 early gastric carcinomas and 31(100%) of 31 advanced gastric carcinomas by two-phase spiral CT. The overall detection rate of gastric carcinomas was 93.9%(46 of 49 cases). The detection rate of early gastric carcinoma was 100%(5 of 5 cases) among elevated lesions and 76.9%(10 of 13 cases) among flat or depressed lesions. With regard to the depth of tumor invasion, there was good correlation between CT findings and pathologic findings in 28 of 49 cases(57.1%). Overstaging occurred in 24.5%(12 of 49 cases) and understaging in 18.4%(9 of 49 cases). In lymph node staging, good correlation between CT findings and pathologic findings was noted in 33 of 49 cases(67.3%). Understaging occurred in18.4%(9 of 49 cases) and overstaging in 14.3%(7 of 49 cases). All of liver metastases(3 cases) and peritoneal carcinomatosis(1 case) were correctly diagnosed by two-phase spiral CT. Conclusion: In the staging of gastric carcinoma, two-phase spiral CT is useful in the deterction of early gastric carcinoma and distant metastasis. However, for determining the depth of tumor invasion and for the evaluation of metastasis to lymph node its usefulness is limited. Further research using various analytic approaches will therefore be necessary.

고강도 콘크리트를 사용한 철근콘크리트 보의 전단 거동에 관한 실험적 연구

김창희,고봉수,은희창,서일교 제주대학교 공과대학 첨단기술연구소 2001 尖端技術硏究所論文集 Vol.12 No.2

The shear capacity of reinforced concrete beam depends on the strength of concrete, the amount and strength of shear reinforcement bars, the support conditions of end points etc. These factors makes the shear behavior or capacity of reinforced concrete beam be complicated. For the purpose of grasping the shear behavior and capacity of reinforced concrete beams, sixteen specimens were tested. Most of specimens showed the shear failure along with the yielding of longitudinal bars or crushing of compressive concrete. The effects on each of test variables were related to the shear capacity of reinforced concrete beams. And, the comparison of the test results and ACI code showed the reasonable agreement.

이방성판재의 2축인장 한계변형률 예측

김창만,서대교 成均館大學校 科學技術硏究所 1993 論文集 Vol.44 No.1

In this paper, the fracture strain in biaxial tension subjected to arbitrary tensile stress ratio, χ is theoretically predicted. Nakajima's analysis was adopted in order to compare the theoretical and experimental results. The conclusions are as follows : 1. The theoretical fracture strains calculated with R-values chosen at about 15% strain level show a good agreement with experimental results at the stress ratio, a = 1.0-1.6 for Brass and α = 1.0∼1.22 for Copper. 2. The R-values at 7%∼12% of strain for Brass were abrubtly decreased to R_0 = 0.3∼0.12 and R_90 = 0.32∼0.15, but had nearly constant values as R_0 = 0.073 and R_90 = 0.113 beyond 15% strain. 3. The R-values at 7%∼12% of strain for Copper were abrubtly decreased to R_0 = 0.28∼0.11 and R_90 = 0.49∼0.14, but had nearly constant values as R_0 = 0.086 and R_90 = 0.12 beyond 15% strain. 4. The increase of R-values and work hardening exponents(n) for Brass and Copper resulted in increasing of the fracture strain, but the increase of plasticity factor(C) resulted in decreasing of the fracture strain.

인문학으로서 중국문학 가르치기

류창교 韓國中國語文學會 2003 中國文學 Vol.40 No.-

주택재건축/재개발사업의 정비사업전문관리에 대한 CM적용방안

김창교,전재열 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.2

A new act as an important law, titled "Consolidation Act for Urban and Residential environment" compromised "Professional Consolidation Project Management system" was promulgated by Ministry of Construction and Transportation, entered effective as of July 1, 2003. This system which is improving and leveling-up previous consulting process implements the essential Tasks for housing complex of reconstruction/redevelopment through the processes and procedures. Tasks from them need to be added the construction management tasks on the reasonable, logical, systematic tool. Depending upon joining the Professional Consolidation Project Management, CM will deliver a lot of benefits, greater than to an housing association, to structured many inhabitants in the project.

제주도 현무암 쇄석조골재를 사용한 콘크리트의 강도에 관한 실험적 연구

서일교,양창희 濟州大學校 産業技術硏究所 1999 산업기술연구소논문집 Vol.10 No.2

There are many factors to influence on the physical properties of the concrete. such as the size and shape of aggregates, W/C ratio and the strength of cement, etc. Cheju island is regionally volcanic island. The coarse aggregates to be generally utilized for producing the concrete in Cheju island are the crushed ones of basalt. However, the aggregates are locally different chemical and physical properties and these differences show different properties of concrete. In this study, we investigated the properties of concrete by the utilization of crushed aggregates from two places. Sangchang and Sangga in Cheju island through the test of compressive. tensile. and flexural strength with curing time.