고분자형 자외선 안정제를 함유한 SBR과 NR의 UV 노화 거동에 관한 연구

남경태 ( Kyoung Tae Nam ),홍창국 ( Chang Kook Hong ),채규호 ( Kyu Ho Chae ),강신영 ( Shin Young Kaang ) 한국고무학회 2006 엘라스토머 및 콤포지트 Vol.41 No.3

본 연구에서는 고분자형 자외선 안정제 DGEBA-HALS의 광분해 억제 효과를 평가하기 위해 SBR과 NR 고무를 사용하여 광안정제 첨가에 따른 UV 조사 영향을 고찰하였다. 이를 위해 광안정제를 첨가하지 않은 배합고무, 사용화된 광안정제인 Cyabsorb UV-3529를 첨가한 배합고무, 그리고 고분자형 DGEBA-HALS를 첨가한 배합고무의 영율, 인장장고, blow-off 변형, 가교밀도 측정을 통한 시편의 물리적 특성변화 등을 관찰하였다. UV 조사 후 모든 시편에서 영율이 증가하였으며 인장강도는 광안정제를 첨가한 시편이 첨가하지 않은 시편보다 우수했다. 특히 NR의 경우 DGEBA-HALS 첨가 시 인장강도가 향상되었다. Blow-off 변형 실험결과도 영율 실험 결과와 비슷하였다. UV-vis transmissinon spectra를 통한 SBR 배합고무의 투과도를 조사한 결과 광안정제를 첨가함으로써 약 4%의 향상된 투과도를 보였다. Cyabsorb UV-3529와 DGEBA-HALS의 첨가는 비슷한 경향의 투과도를 나타내었다. SEM을 통해 시편의 표면을 관찰한 결과 광안정제를 첨가함으로써 UV 조사에 의한 균열의 크기가 작아짐을 알 수 있었고, 특히 DGEBA-HALS는 상용화된 Cyabsorb UV-3529 보다 더 좋은 광분해 안정효과를 갖는 것을 확인할 수 있었다. The retardation effects of a new polymeric UV stabilizer, DGEBA-HALS, on the UV degradation of SBR and NR were investigated in this study. The UV degradation behaviors of three different rubber compounds, without any photostabilizer and with commercial Cyabsorb UV-3529 and DGEBA-HALS, were compared. Also, the physical characteristics such as Young`s modulus, tensile strength, blow-off deformation and crosslink density were examined. The Young`s modulus was increased by UV irradiation for all samples, and the tensile strength, after UV irradiation, of the compound with UV stabilizer was better than that of the compound without stabilizer. Especially, the tensile strength of UV irradiated NR was improved by adding DGEBA-HALS. The results of blow-off deformation were in accord with those of Young`s modulus. The degree of transmission of SBR compounds obtained from UV-vis transmission spectra was improved about 4% by adding the UV stabilizer. Commercial Cyabsorb UV-3529 and DGEBA-HALS showed similar trends of transmission. The SEM photographs of SBR surface showed that the size of cracks created by UV irradiation became smaller by adding UV stabilizer. In particular, it is observed that the stabilization effect of DGEBA-HALS was better than that of commercial Cyabsorb UV-3529.

쓰레기 매립장 주변 농촌 주민들의 삶의 질 연구

이명경,최준열,김인경,조영아,김영신,정혜진,김리나,이영규,조영태,Lee, Myung-Kyung,Choi, Jun-Yeol,Kim, In-Kyoung,Cho, Yeong-Ah,Kim, Young-Shin,Jung, Hye-Jin,Kim, Li-Na,Lee, Young-Kyu,Cho, Young-Tae 대한예방의학회 2006 예방의학회지 Vol.39 No.4

Objectives: This study aims to examine if a garbage dumping site has real and negative influence on the quality of life (QOL) for the nearby residents. The net effects of the residential distance from the garbage dumping site and from the garbage truck route were investigated for five domains of the QOL. Methods: Two hundred fifty seven Shin-dong Myeon residents, Chun-cheon Si, participated in a self-administrated survey. The Shin-dong Myeon garbage dumping site began operating in 1996. ANCOV A with generalized linear models and multiple regression analysis were performed. Results: Descriptive analyses show that a residence nearby a garbage dumping site is negatively associated with the physical and environmental domains of the QOL. The residential distance from the garbage truck route does not exert any significant effect on various domains of QOL, except for the environmental domain. On the multivariate analysis, the residents living near the garbage dumping site tended to have a significantly negative QOL in the physical and environmental domains. However, the distance from the garbage truck route did not show a significant nor substantial effect on the QOL. The demographic and socioeconomic control variables are associated with a number of the QOL domains, and their patterns are consistent with the general expectations. Conclusions: The results indicated that a garbage dumping site is considered to be an environmental hazard among the nearby residents according to the lower scores on the physical and environmental domains of the QOL. The findings from this study provide comprehensive understanding on the residents' QOL, and they may help politicians and policy makers make decisions for appropriate interventions.

경계층 난류박리의 제어에 관한 연구 : 제1보;매끄러운 2차원 디퓨저 벽면에서의 난류박리특성 First Report;Turbulent Separation Characteristic on the Smooth 2-Dimensional Diffuser Wall Surface

신정관,박종일,이한영,김경훈 경희대학교 산학협력기술연구원 1995 산학협력기술연구논문집 Vol.1 No.-

The structure of the turbulent wall layer developing into flow separation was studied. The experiments were performed to find out the formation of turbulent separation lead to diverging of the diffuser wall in a two-dimensional asymmetric diffuser which was attached to a downstream end of a long straight channel to provide a fully-developed turbulent inlet condition. First report, this is to estimate how to develop the region of the separation in the smooth diffuser wall with diverging condition and then is the reference on the characteristics of rough diffuser wall being under discussion at second report. As a result, static pressure profile of the fixed wall are in accord with the static pressure profire of the movable wall. Separation has broken out at the diffuser open angle θ=7o, while the diffuser openingangle is increasing, the region of the separation is advanced at the upstream and separation appears at the diffuser open angle θ=12o in the fixed wall too.

계면활성제 함유 인지질 나노입자의 초가변성 연구

신지영,오유경,강민정,권경애,김종국 한국약제학회 2003 Journal of Pharmaceutical Investigation Vol.33 No.3

This study was aimed to formulated various phospholipid nanoparticles composed of different surfactants and to evaluate the deformability of the phospholipid vesicles as candidates of useful ultradeformable nanoparticles. In vitro deformability of the hospholipid nanoparticles was studied using an extruder under a certain pressure. The sizes of phospholipid nanoparticles, passed volumes, and concentrations of the phospholipids in suspensions before and after extrusion were measured. The deformability indexes were estimated by using passed volumes, sizes of phospholipid nanoparticles and concentrations of phospholipids. Conventionl liposomes, placed under a certain pressure of an extruder, showed no passed volume indicating little deformability. Similar to conventional liposomes, phospholipid nanoparticles containing surpactants such as sodium taurcholate, Myrj 45, or Myrj 53 showed little deformability. In contrast, phospholipid nanoparticles composed of Tween 20, triton X-100, or sodium deoxycholate showed higher deformability indexes than others. Taken together, the deformability of phospholipid nanoparticles could be significantly affected by the type of surfactants. Moreover, these results suggest that the deformability of phospholipid nanoparticles could be modulated by surfactants.

배양 조건이 Candida albicans의 phospholipase 생성에 미치는 영향

신운섭,이경호,박주영,고춘명 대한의진균학회 1997 대한의진균학회지 Vol.2 No.2

Background : The dimorphic yeast, Candida albicans, is considered as a dangerous opportunistic pathogen in immunocompromised hosts. Several phospholipases of C. albicans are known to be secreted into the culture medium. Phospholipases have been proposed as a virulence factor in the pathoenesis of Candida infections. Objective : In order to investigate enzyme production, we examined culture condition of secreted phospholipase production from C. albicans. Methods : C. albicans ATTCC 10231 was cultivated in various media at 37℃ for 3 days. Phospholipase activity was measured by fatty acid soap precipitaiton in plate containing 0.04T lecithin, 0.1 M citrate buffer, pH 4.2 and 1.5% noble agar. Results : Phospholipase was highly induced when C. albicans was cultivated in broth medium(containing glucose 2%, albumin 0.2% and Fe^++ ion 0.01%) and Saboulaud's dextrose agar supplemented with 0.01% sodium deoxycholate. Conclusion : Highly induction of secreted phospholipase by albumin from C. albicans may be play an importans role in tissue invasion in the pathogenesis of C. albicans.

SoC 플랫폼에서 다층구조 공유버서의 레이턴시 모델과 해석

조영신,조경록 충북대학교 컴퓨터정보통신 연구소 2005 컴퓨터정보통신연구 Vol.13 No.1

SoC 설계 기술의 발달로 하나의 칩내에 집적되는 시스템이 다양한 기능을 수행함에 따라 높은 버스 대역폭이 요구되고 있으며, 시스템 버스의 성능이 전체 시스템의 성능에 큰 영향을 미치고 있다. 본 논문은 다중 마스터를 갖는 SoC용 플랫폼의 효율적인 버스 자원 관리를 위해 다층 구조를 갖는 공유 버스의 레이턴시 모델을 제안하였다. 시뮬레이션 결과 제안된 버스 시스템 환경에서, 시스템이 단일 전송률 20%와 버스 사용률 50%를 가질 때, 2-layer와 3-layer가 1-layer와 비교하여 각각 약 45%와 약 63%의 레이턴시가 감소하였다. 또한 레이턴시 모델을 통해 버스의 사용량과 전송 방식의 관계를 분석하였다. 끝으로 레이턴시 모델에 버스의 동작 주파수와 데이터의 전송 크기를 대입하여 레이어의 수에 따른 버스 처리량을 구하였다. 구해진 버스 처리량과 MPEG, USB2.0과 같은 IP를 포함하는 SoC플랫폼이 필요로 하는 처리량과의 비교를 통해 IP 수에 적합한 버스 레이어를 정량화하여 특정 SoC플랫폼에 최적인 멀티레이어 구조를 도출하였다. Nowadays a SoC(system-on-a-chip) requires high bandwidth system bus for performing multiple functions. Performance of the system is affected by bandwidth of the system bus. In this paper, for efficient management of the bus resource on a SoC platform, we present a latency model of the shared bus organized by multiple layers. As the results of simulation, the latency of 2-layer and 3-layer bus architecture are reduced 45% and 63% respectively to compare with a single-layer's under the assumed conditions of the proposed model. We could analysis the relationship between a bus usage and a transfer protocol using the proposed model. Finally we evaluate a throughput of the bus and compared with a needed throughput by SoC platform including IPs such as MPEG or USB 2.0. We can use the results as a criteria to find out an optimal bus organization for the specific SoC design.

Coxiella burnetii에 대한 항체의 검출을 위한 Enzyme-Linked Immunosorbent Assay의 정립

이경호,박주영,박윤선,김수기,신운섭,고춘명 대한감염학회 1994 감염 Vol.26 No.4

본 연구에서는 지금까지 진단이 내려지지 않았던 C. burnetii 감염증 환자들을 보다 빠르고 간편하며 정확하면서도 대량으로 검사할 수 있는 방법으로서 C. burnetii 단백항원을 이용한 효소면역측정법을 정립하고자 하였다. 본 실험에서 정립한 효소면역측정법은 간접 방법으로서 C. burnetii phase I에 대한 IgG를 검출하기 위해 고안되었다. C. burnetii 단백질 항원의 적정 농도는 야성 대조혈청의 흡광도와 음성 대조혈청에서의 흡광도의 차이가 가장 크게 나는 농도인 1ug/ml을 적정항원농도로 결정하였으며, 검사 혈청의 적정희석 농도도 역시 양성대조항원의 OD 값과 음성대조항원에서의 OD값의 차이가 가장 크게 나면서 비교적 background activity가 적은 혈청의 희석 농도인 1:300을 적정 혈청 희석 농도로 결정하였다. 이 때 각각의 야성 혈청이 0.185의 흡광도를 가질 수 있는 가장 높은 혈청 희석 농도의 로그값과, 같은 혈청을 1:300으로 희석했을 때의 흡광도 사이에 상관계수 r값이 0.95인 직선적 관계가 성립하여, 하가지 혈청 희석 농도(1:300)에서 결정된 ELISA값이 그 혈청의 항체가를 양적으로 표시하였다. 효소면역측정법의 양성 판정 기준은, IFA에서 C. burnetii에 대한 항체가 음성으로 확인된 혈청 100개를 대상으로 ELISA를 시행하여, 이들의 흡광도의 산술평균치와 표준편차를 구한 결과, 신뢰구간 95%에서 최고치인 0.185를 ELISA 야성 판정의 기준인 cut-off value로 정하였다. 위애서 정한 기준에 의해 ELISA를 시행하엿을 때, IFA에서 양성으로 판명된 혈청 모두에서 양성으로 나타나 민감도가 매우 높은 것으로 나타났다. 다음으로 ELISA 방법의 특이도를 조사하기 위해서, IFA 검사에서 음성으로 확인된 혈청(혈청 희석 농도 1:10에서 음성)을 대상으로 ELISA를 시행한 결과, blocking agent로서 1% BSA를 사용했을 때는 9.3%, 5% NGS는 11.3%, 그리고 blocking을 전혀 하지 않았을 때는 15.3%의 위양성율을 나타내어, BSA와 NGS 상이에는 통계학적으로 차이가 없었으나, blocking을 하지 않는 것 보다는 하는 것이 위양성율이 적은 것으로 나타났다. 그러나, 이것은 어디까지나 IFA기준이며, 절대적인 의미에서의 위양성율을 의미하는 것은 아니다. 결론적으로 본 연구에서 정립한 효소면역측정법은 매우 높은 민감도를 갖고 있으므로 Q fever가 의심되는 환자를 screening하기 위한 적절한 방법으로 사료된다. Currently, the indirect immunofluorescence assay(IFA) is used for detecting antibodies to Coxiella burnetii. Although reliable, this method is time-consuming, and the results are subject to interpretation. To develop an alternative test, we used an enzyme-linked immunosorbent asssy (ELISA) because it was faster, less complicated, and more objective than the IFA. The ELISA, unlike the IFA, can also be automated. In this study an indirect ELISA using C. burnetii protein antigens was developed to detect immunoglobulin G to C. burnetii phase I. A linear relation was found between the logarithms of absorbance values of sera at a dilution of 1/300 and the titres as determined by an end point dilution ELISA. The finding of linear relation (r=0.95) confirmed that an ELISA value determined with a single serum dilution (1:300) can be interpreted quantitatively as the titer of antibody in that serum. A serum dilution of 1:300 was used in all subsequent tests because at this dilution the difference between absorbance values for positive and negative sera was greatest: a serum sample was regarded as positive if the OD? value was ≥0.185 (absorbance threshold) at this dilution. The results obtained by the ELISA were compared with those by the IFA established already. The results indicate that the assay provides a sensitive, alternative method for diagnosing Q fever, but it needs reevaluation for the specificity because of its high false-positive rates.

有機農業의 實態와 發展에 관한 事例 硏究 : 忠南 洪城郡 洪東面 有機農家를 中心으로

尹英相,洪性贊,金成敏,具漢謨,申東一,金昌護,姜熙慶 公州大學校 資源科學硏究所 1997 資源科學硏究論文集 Vol.5 No.-

This study was carried out to improve the organic farming system about crop cultivation, compost production and application, plant diseases & pest control, weed control and marketing system of organic farming products to the case study in Chungnam Hongdong area. Agricultural technologies concerning pest & diseases control, weed control and compost production are not established due to lacks of systemized researches by the agricultural scientist, and agricultural machines profitable to this works had not developed yet. In cropping system, reasonable crop rotation had not conducted. The related cultivation of vegetables on the same ground for a long time cause a various plant disease easily. So crop rotation is a reasonable method about soil nutrient utility and soil disease control. It is a good method that introduce the barley and wheat in this field crop system. Those crop have a long root, so can use the other nutrient against the vegetable. In organic farming products, the safety and quality of products by the National Agricultural Products Inspection Center had not inspected except rice, lettus and apple. Inspection is needed for the development of organic farming and mutual confidence between producer and consumer, because the mutual confidence is a major thing to sustain the organic farming. In products marketing, it is more need for the information of organic farming products. Nowaday most products are marketed in Seoul region, but it is not a good method. To search the consumer in near region is a good method for decrease the cost of conveyance and maintain the quality of products. The varieties of distribution structure of organic farming products are required. The products are sold to department store in large city and the prices are about 30% higher than normal products. But when those are supplied in near region, the prices of those are similar to normal products. Direct transactions in near regions is a good method for decrease the cost of conveyance and strength the mutual confidence between producer and consumer.

연속파형 Nd:YAG SM45C 레이저 용접의 결함 감소연구

유영태,오용석,노경보,신호준 朝鮮大學校 機械技術硏究所 2003 機械技術硏究 Vol.6 No.1

본 연구에서는 Nd:YAG 연속파형 레이저를 이용하여 레이저 용접시 레이저빔의 출력에 대한 레이저범의 이송속도를 변화시켜 심입용접을 실시했다. 열처리를 하지 않고 용접을 실시했을 경우 매우 조대한 기공이 많이 발생하였지만 열처리 후 용접을 실시했을 때는 몇몇 미세한 기공만 발생하였다. Present investigation reports on the effect of incorporating pre-heating on the mechanical properties of laser weldi'ng joints. The Nd:YAG laser in combination with the optical fiber increase the automation and the flexibility of a whole industry. The Nd:YAG laser welding process is one of the most advenced menufacturing technologies owing to its high sped and penetration. This paper describes the weldability of Sh4456 carbon steel fox machine structural use by Nd:YAG laser. Optical microscopy SEM were performed to observe the micro structures and to determine the structures of welded zone. In addtion, mechanical propreties, were measured by tensile test to evaluate the formablity of the welded specimen. The results show that proper selection of the control parameters for per-heating technique can result the porosity and cracking of the welding significantly, and improve the welded joints mechanical properties, such as higher tensile strength and better durability.

치환된 프로탈로시아닌의 합성 방법 연구

河潤卿,金永寬,孫秉淸,申鉉萬,朴美敬 弘益大學校 科學技術硏究所 1996 科學技術硏究論文集 Vol.7 No.1

The octadodecanoxy derivative of the phthalocyanine which has such long hydrocarbon chains around the skeleton of the phthalocyanine was synthesized. First of all, ortho-catechol was treated with 2 moles of 1-bromododecane to yield ortho-didodecanoxybenzene(I). Second, bromination of I resulted in dibromo-didodecanoxy benzene(II) where the para positions to the dodecanoxy groups were brominated. Finally, reaction of II with an excess of CuCN under an N₂atmosphere gave the intermediate dicyano-didodecanoxy-benzene(III), in situ, and futher heating in dry DMF with more CuCN gave the final product, octadodecanoxy derivative of the phthalocyanine. The synthetic method developed herein provides a general way to synthesize the variety of the phthalocyanines which displays many different substituents such as long hydrocarbons around its skeleton and contains a various metal inside of the phthalocyanine.