폴리이미드는 뛰어난 기계적 강도, 내열성, 내화학성 및 여러 기체에 대한 높은 투과선택성을 가지고 있으나 유기용매에 대한 낮은 용해성으로 인해 제막할 경우 많은 제약을 받고 있다. 따라서 유기용매에 가용성을 가지는 폴리이미드에 대한 연구가 필요하다. 본 연구에서는 지환족 다이안하이드라이드인 5-(2,5-dioxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicar boxylic (DOCDA) 와 다양한 다이아민을 이용하여 DOCDA계 폴리이미드를 합성하였다. FT-IR을 통해 합성이 잘 이루어졌음을 확인하였고, 용해도 테스트를 통해 여러 유기용매에 대한 용해성을 확인하였다. 또한, 기체투과특성을 알아보기 위하여 time-lag 장비를 이용하여 투과도 및 선택도를 알아보았다.

PURPOSES : This research was a laboratory study for evaluating the Reclaimed Asphalt Pavement (RAP) mixture added developed rejuvenator for warm mix recycling. Waste asphalt mixtures occupy about 18.2% of construction wastes in Korea. Moreover, most rejuvenators were imported from Europe or the U.S. Therefore, improving usage of RAP with a developed rejuvenator material provides environmental protection at a reduced cost. METHODS : The specimen used for this experiment was performed by only using RAP. A suitable rejuvenator for Target PG was then added. In addition, a conventional rejuvenator was selected to compare performance and specimens introduced with the same procedure as the developed rejuvenator was prepared. In order to evaluate rutting resistance and water susceptibility, we conducted a deformation strength test, a tensile strength ratio test, and a dynamic immersion test with the prepared mixtures. RESULTS: Laboratory test results indicated that both the developed additive and conventional additive improved performance of the recycled asphalt mixtures compared to mixtures without the rejuvenator. In addition, the deformation strength test and TSR test results satisfied standards for domestic recycling asphalt mixtures. The dynamic immersion test showed that the developed rejuvenator has superior scaling resistance than the conventional rejuvenator. CONCLUSIONS : In terms of rutting resistance and moisture susceptibility, the warm mix recycled asphalt mixtures with the developed rejuvenator appeared to effectively recovered performance.

With the increased globalization, selecting suppliers has become more challenging problem, especially because of increased risks among suppliers. This paper proposes a four-step supplier selection procedure in global supply chains under risk. In the first step, appropriate supplier selection solutions are determined by using a rule-based expert system. In the second one, these solutions are used to evaluate suppliers’ general performance. In the third one, suppliers’ risks are evaluated by using a risk evaluation algorithm. In the fourth one, Pareto optimal suppliers are selected based on their general performance and risk evaluation outputs. An example demonstrates the implementation of the proposed procedure.

Pleomorphic adenoma is the most common benign tumor of the salivary glands. About 80-90% of pleomorphic adenoma occurs in the parotid gland and about 5-10% of them occur in the submandibular gland and sublingual gland. The rest proportion comprises the minor salivary glands. The palate is the most common area, followed by the lips and the cheeks. Pleomorphic adenoma of the submandibular gland shows clinically a slow-growing, painless mass found on submandibular aspect. In this case report, we report a case of pleomorphic adenoma of the right submandibular gland in a 63-year old female patient who was referred from the department of neurosurgery, due to the heterogenous mass detected by computed tomography (CT) and magnetic resonance imaging (MRI)

작용기작이 동일한 농약을 연속하여 사용하였을 때 방제대상이 되는 병해충·잡초 중 약제에 대한 저항력이강한 개체들만이 살아남게 되고 다음세대에서도 같은 현상이 반복된 결과 저항력이 더욱 증가되어 이전에 사용한약량으로는 병해충･잡초가 방제되지 않는 약제저항성 현상이 나타난다. 신규살충제는 시장에 판매되는 첫 해부터대상해충의 저항력이 언제 나타나는지를 파악하기 위해서 주기적인 약제저항성 모니터링을 하여야 한다. 파밤나방은파, 배추 등의 주요한 작물의 해충으로 신규 살충제들의 중요 방제대상 해충이다. 파밤나방을 이용한 약제저항성모니터링 시험을 하기 위해서는 채집지역 선정, 약제농도설정, 유충사육기술, 생사충 판단기준설정, 데이터분석프로그램운용 및 약제저항성 판정기준설정 등의 여러 요인들에 대한 기술과 관리가 요구된다. 약제저항성 모니터링시험은 장기간에 걸쳐 일관성 있게 유지되어야 하는 시험이기 때문에 종합적이고 체계적인 관리를 필요로 한다.

최근 이산화탄소 발생량이 증가함에 따라 지구온난화 문제가 심각해지고 있는 가운데 국내에서도 기록적인 폭우로 인한 홍수 및 침수 피해가 급증하는 등 아열대성 기후의 특징이 점차 부각되고 있다. 이처럼 증가한 강우량 및 강수일수는 수분으로 인한 아스팔트 포장의 파손 증가로 이어지고 있다. 수분에 의한 아스팔트 포장 파손의 가장 대표적인 사례인 포트홀의 발생 현황을 보면 2006년도에는 3만 8천건이 발생한 반면 2010년에는 7만 7천건으로 두배 이상 급증하였다(서울연구원, 2012). 이처럼 급증하는 아스팔트 포장의 수분파손을 저감하기 위해 국토교통부의 ‘아스팔트 콘크리트 포장 시공 지침(2017)’에서는 동적수침 후 피복율을 점검하도록 규정하고 있다. 동적수침시험은 수분이 골재와 바인더에 미치는 영향을 평가하는 시험으로 일정한 크기의 골재를 피복하여 동적수침 후 2명의 시험자가 육안으로 피복율을 판별한다. 하지만 동적수침 시험은 정량화되고 계량화된 판별법이 아닌 관찰자의 숙련도 및 주관이 개입될 여지가 많은 판별법으로, 관찰자에 따라 결과가 상이하고 반복성이 떨어져 신뢰도가 낮은 단점이 있다. 이를 보완하기 위해 Digital Image Analysis를 이용한 분석법등이 제안되었지만, 화강암의 어두운 부분이 바인더가 잔존하는 것으로 계산될 수 있다는 단점이 있다(손정탄 외, 2016). 본 연구에서는 육안조사 및 선행연구에서 제시한 판별법의 단점을 개선하기 위해 시험 후 골재표면에 피복되어 있는 아스팔트 중량을 이용해 피복율(이하 중량판별법)를 측정하고자 하였다. 이를 위해 11.2 ∼8mm 크기의 화강암 골재와 PG 64-22 바인더를 이용하여 시료를 제작하였고 피복한 시료의 무게(A)를 측정한 후 동적수침시험을 실시하였다. 시험이 끝난 시료는 시험자가 육안조사를 먼저 실시하였으며, 이를 건조로에서 항량이 될 때까지 건조한 후 무게(B)를 측정하였다. 이후 소각을 통해 골재 표면에 피복되어있는 AP를 제거한 후 골재만의 무게(C)를 측정하였고, 이를 이용해 시험 전(A-C)·후(B-C) 골재에 피복되어 있던 AP의 중량을 구하였다. 이렇게 구한 AP의 중량의 비((B-C)/(A-C)×100)를 이용해 피복율을 계산하였다. 시험 결과, 육안조사 및 중량판별법의 평균과 표준편차는 각각 55.56%, 2.04와 52.15%, 2.01로 나타났다. 표준편차는 유사한 수준으로 반복성 및 재현성에서 큰 차이를 보이지 않았지만 평균은 중량판별법이 약 3% 작게 나타났다. 중량판별법의 평균이 작은 이유는 육안조사 과정에서 AP가 일부 소실된 시료를 소각 및 중량판별하였기 때문인 것으로 판단된다. 판별법에 따른 결과값의 차이가 유의미한 것인지를 검증하기 위해 T-test를 실시한 결과, p값이 유의수준 0.05보다 작아 결과값의 차이가 유의미함을 알 수 있었다. 판별법간의 상관정도를 보여주는 상관계수는 0.63로 강한 상관관계를 보였으나 회귀분석을 통한  는 0.3989으로 작게 나타났다. 상관관계가 높음에도 불구하고  가 작은 이유는 판별법에 따른 결과값의 차이가 균일하지 않기 때문으로, 이는 피복AP 제거를 위해 시료를 소각하는 과정에서 고온으로 인해 파손 및 소실되는 골재의 양이 균일하지 않기 때문으로 판단된다. 연구 결과, 중량판별법은 기존 육안조사의 단점인 시험자의 주관 및 선입견을 배제하고 숙련도에 관계없이 육안조사와 유사한 수준의 결과값을 도출할 수 있는 객관적인 판별법이라 판단된다. 그러나 본 연구에서는 한정된 골재 및 바인더에 대해 시험한 결과로 이를 실제로 적용하기에 위해서는 다양한 재료에 대한 적용가능성 검증이 선행되어야할 것이다. 또한 소각용 Pan의 개량 및 적정온도 선정에 대한 추가 연구를 통해  값을 향상시켜야 할 것이다

Pig has been known to be one of the most feasible animals as a bioreactor to produce pharmaceuticals in milk and as a mediator in xenotransplantation research. Previously, we generated transgenic pigs for both purposes, which were expressing Factor 8, vWF, hTPA, and hEPO in milk, along with expression of MCP at GalT gene locus (GalT-MCP/-MCP) as well as expressing MCP at GalT gene loci with CD73 expression (GalT-MCP/+/CD73). In this study, we performed comparative analyses of sperm parameters between wild type male (WT) pig and those transgenic males to examine the effects of transgenes integrated into the pigs on motility, morphology, viability, and acrosome integrity of the spermatozoa. Our results showed that the rates of actively motile spermatozoa of WT, Factor 8, vWF, hTPA, hEPO, GalT-MCP/+/CD73, and GalT-MCP/-MCP pigs were 85.0%, 83.3%, 82.5%, 83.3%, 82.5%, 77.5%, and 78.7%, respectively. Whereas, the rates of morphologically normal spermatozoa of WT, Factor 8, vWF, hTPA, hEPO, GalT-MCP/+/CD73, and GalT-MCP/-MCP pigs were 90.0%, 80.0%, 80.0%, 83.3%, 85.0%, 91.8%, and 80.8%, respectively. In addition, the viability in spermatozoa of WT, Factor 8, vWF, hTPA, hEPO, GalT-MCP/+/CD73, and GalT-MCP/-MCP pigs were 93.9%, 82.4%, 89.9%, 83.9%, 87.4%, 92.8%, and 83.6%, respectively. The rates of spermatozoa with normal acrosome integrity in WT, Factor 8, vWF, hTPA, hEPO, GalT-MCP/+/CD73, and GalT-MCP/-MCP pigs were 98.1%, 98.6%, 98.6%, 98.7%, 98.1%, 99.5%, and 95.1%, respectively. There were no significant differences in motility, morphology, viability, and acrosome integrity of the spermatozoa among WT, Factor 8, vWF, hTPA, and hEPO, GalT-MCP/+/CD73, and GalT-MCP/-MCP pigs. These mean that neither random integration nor targeted integration of the transgene into chromosome of pig effect on characteristics of spermatozoa. Ultimately, the transgenic male pigs subjected in this study could apply to propagate their progenies for production of human therapeutic proteins and advancing the xenotransplantation research.

Pigs have been extensively used as mediators of xenotransplantation research. Specifically, the Massachusetts General Hospital (MGH) miniature pig was developed to fix major histocompatibility antigens for use in xenotransplantation studies. We generated transgenic pigs for xenotransplantation using MGH pigs. However, it has not been studied yet whether these pigs show similarity of reproductive physiological characteristics to wild types of MGH miniature pig. In this study we analyzed the estrous cycles and pregnancy characteristics of wild type (WT) and transgenic MGH miniature pigs, which were α1,3-galactosyltransferase (GalT) heterozygous and homozygous knock-out, and membrane cofactor protein (MCP) inserted in its locus, GalT-MCP/+ and GalT-MCP/-MCP pigs. Estrous cycles of WT, GalT-MCP/+ and GalT-MCP/-MCP pigs were 20.9±0.74, 20.1±1.26, and 17.3±0.87 days, respectively, and periods of estrous were 3.2±0.10, 3.1±0.12, and 3.1±0.11 days. The periods of gestation of WT, GalT-MCP/+ and GalT-MCP/-MCP pigs were 114.2±0.37, 113.3±0.67, and 115.4±0.51 days, respectively. Litter sizes of WT, GalT-MCP/+ and GalT-MCP/-MCP pigs were 4.8±0.35, 4.8±1.11 and 3.0±0.32 respectively. There were no significant differences on estrous cycle, periods of estrous and gestation, and litter size among WT, GalT-MCP/+ and GalT-MCP/-MCP pigs, meaning that GalT knock-out and additional expression MCP of the MGH miniature pig did not effect on reproduction traits. These results provide relevant information to establish breeding system for MGH transgenic pig, and for propagation of GalT-MCP/-MCP pig to supply for xenotransplantation research.

Transplantation is considered to be a very useful approach to improve human welfare and to prolong life-span. Heterologous organ transplantation using pig organs which are similar to human beings and easy to make mass-production has known as one of the alternatives. To ensure potential usage of the pig organ for transplantation application, it is essentially required to generate transgenic pig modifying immuno-related genes. Previously, we reported production of heterozygous α 1,3-galactosyltransferase (GalT) knock-out and human membrane cofactor protein (MCP) expressing pig (GalT-MCP/+), which is enforced for suppression of hyperacute and acute immunological rejection. In this study, we reported generation of homozygous pig (GalT-MCP/-MCP) by crossbreeding GalT-MCP/+ pigs. Two female founders gave birth to six of GalT-MCP/-MCP, and seven GalT-MCP/+ pigs. We performed quantitative real-time PCR, western blot, and flow cytometry analyses to confirm GalT and MCP expression. We showed that fibroblasts of the GalT-MCP/-MCP pig do not express GalT and its product Gal antigen, while efficiently express MCP. We also showed no expression of GalT, otherwise expression of MCP at heart, kidney, liver and pancreas of transgenic pig. Taken together, we suggest that the GalT-MCP/-MCP pig is a useful candidate to apply xenotransplantation study.

In this study, Fe-Cu-C alloy is sintered by spark plasma sintering (SPS). The sintering conditions are 60 MPa pressure with heating rates of 30, 60 and 9oC/min to determine the influence of heating rate on the mechanical and microstructure properties of the sintered alloys. The microstructure and mechanical properties of the sintered Fe-Cu-C alloy is investigated by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM). The temperature of shrinkage displacement is changed at 450oC with heating rates 30, 60, and 90oC/min. The temperature of the shrinkage displacement is finished at 650oC when heating rate 30oC/min, at 700oC when heating rate 60oC/min and at 800oC when heating rate 90oC/min. For the sintered alloy at heating rates of 30, 60, and 90oC/min, the apparent porosity is calculated to be 3.7%, 5.2%, and 7.7%, respectively. The hardness of the sintered alloys is investigated using Rockwell hardness measurements. The objective of this study is to investigate the densification behavior, porosity, and mechanical properties of the sintered Fe-Cu-C alloys depending on the heating rate.

The research vessel NARA equipped with an azimuth thruster system was built in 2015. There are few vessels with this propulsion system in Korea. This vessel has two modes such as the normal for maneuvering and the power for investigation, and the other two modes as one axis and two axes on the operating. This type of vessels does not seem to have a clear grasp of the maneuvering character in comparison with the vessel with a conventional propulsion system. So the authors carried out the sea test for the turning, the zigzag and the inclination, and the results are as follows. In turning test, the case of using the two axes mode is much better than the case of using the one axis mode for the elements of turning, such as advance, transfer, tactical diameter and final diameter, but turning hard over the rudder in full speed is very vulnerable to capsize in both modes. In zigzag test, the yaw quicking responsibility index,  is very large excessively, which means a bad counter maneuvering ability, so an operator has to keep in mind that in turning operation. If necessary to avoid collision at head on situation, it may be a more effective method to use the crash astern stop than the turning according to the conditions and circumstances for the shortest stopping distance is very short.

This study was conducted to investigate the actual condition of fine particles (PM2.5) pollution and to verify the necessity of managing PM2.5 in the indoor environment of public use facilities in Gyeonggi-do. As a result, it was found that PM2.5 concentrations measured for 24 hours ranged from 15.9 to 113.5 μg/m3 and averaged 42.5 μg/ m3, and for 6 hours, ranged from 20.4 to 167.1 μg/m3 and averaged 65.6 μg/m3. Average concentration was highest in subway stations, followed by nursery schools and indoor parking lots. 49 of the 55 sites investigated exceeded the 24hr-PM2.5 standard specified in WHO guidelines (25 μg/m3). The ratio of PM2.5 to PM10 was 70.2% for 24hr and 70.7% for 6hr on average. This means that PM2.5 tends to account for a large proportion of the total particulate pollution in the indoor environment, and that it is essential to control fine particulate matter in order to reduce total particulate matter in the indoor environment. In addition, it was found that the time to be sampled and total sampling time are one of important factors which affect PM2.5 concentration in indoor air quality; therefore, I think that it is necessary to concretely specify the time to be sampled and maximum range of total sampling time in the test method of PM2.5. Recently, regulations on PM2.5 in indoor environments have been strengthened in other countries due to its high risk to human health; however, there is currently no enforceable regulation in Korea. Given that PM2.5 is more harmful to human health than PM10, it is urgently necessary to establish proper policies and regulations to control PM2.5 in indoor environments.

During the harvest season, drying and storage facilities at Rice Processing Complexes (RPCs) are not enough to manage all the harvested rice, which causes quality deterioration and decomposition. Also, rice export is being limited due to the high cost of long-term storage for shipping. This study was conducted to investigate the germination rate, fat acidity and lipoxygenase activity of brown rice after storage of 3, 6, 9 and 12 months at 25oC and 35oC with 22 Korean and 2 Japanese varieties. Germination rate of rough rice was decreased to 72% after storage of 9 months at 25°C and decreased to 35 and 33% after 3 and 6 months at 25°C, respectively. Fat acidity was increased according to storage periods and increasing level was higher at 35°C than at 25°C. Lipoxygenase activity was decreased according to storage periods and decreasing level was higher at 35°C than at 25°C. Although the protein content was not significantly different according to the storage period at both 25 and 35°C, significant difference existed among cultivars. Amylose content was increased until 6 months at both 25 and 35°C, but decreased after 9 months. Fat acidity and protein content were negatively correlated with amylose content, while amylose content was positively correlated with lipoxygenase activity after 12 months at 25°C. Germination rate was negatively correlated with fat acidity and protein content, while fat acidity was positively correlated with protein content and negatively correlated with amylose content and lipoxygenase activity after 6 months at 35°C. 24 varieties were classified into 3 groups on the basis of germination rate, fat acidity and lipoxygenase activity after 12 months at 25°C and 6 months at 35°C. Group I including 8 varieties of Koshihikari showed higher germination rate, lower fat acidity than Group II including 11 varieties of Nampyeongbyeo.. Honong and Jinbaek. Hopyeongbyeo and Hopum showed higher germination rate, lower fat acidity at 35°C than 25°C, while Hwanggeumnuri showed higher germination rate, lower fat acidity at 25°C than 35°C.

This study was conducted to find out the effects of over seeding using new grass varieties orchardgrass ‘Kordione’ and ‘Onnuri’, and tall fescue ‘Greenmaster’ on botanical composition and dry matter productivity from 2013 to 2016 in low productivity hilly pasture, middle area of Korea. There were used 3 grass seed mixture types made of different compositions and amounts {T1: control - no over seeding, T2: tall fescue (TF) ‘Greenmaster’ 18 kg ha-1, orchardgrass (OG) ‘Kordione’ 9 kg ha-1, Perennial ryegrass (PRG) ‘Linn’ 5 kg ha-1, and Kentucky bluegrass (KBG) ‘Kenblue’ 2 kg ha-1, T3: TF ‘Greenmaster’ 9 kg ha-1, OG ‘Kordione’ 18 kg ha-1, PRG ‘Linn’ 5 kg ha-1, and KBG ‘ Kenblue’ 2 kg ha-1, T4: TF ‘Greenmaster’ 9 kg ha-1, OG ‘Onnuri’ 18 kg ha-1, PRG ‘Linn’ 5 kg ha-1, and KBG ‘Kenblue’ 2 kg ha-1}. In the botanical composition of grassland, T1 nearly remained constant in other seasons while ratio of weeds were increased in summer season. T2 was better than control (T1) in portion of grass ratio, which has increased by 80%. In the early time of establishment, the portions of OG were increased in T2, but TF rate was increased after 3 years later when grass was established. T3 and T4 showed a very similar patterns, grass ratio had increased by 80% and the portion of KBG had increased as time passed. T2 (129,763 kg ha-1) was showed the highest dry matter yield than other treatments (T1: 6,756 kg ha-1, T3: 9641, and T4: 10,738) in 2016.

The objective of this study was to provide fundamental information on fish swimming behavioral properties. Acoustic data was collected at nighttime from the 10th to 12th March, 2016 near Yokji Island in the South Sea of South Korea, and was analyzed using the fish track technique. This technique is to identify groups of single targets, which shows a pattern of systematic movement. As a result, the differences of the behavioral properties such as depth, swimming speed, vertical direction, horizontal direction, tortuosity, and depth change among days were minor; however, statistical results (Welch analysis of variance) showed significant difference between days. Especially, the target strength (TS) of the 11th were significantly different from the 10th and 12th. It could be assumed that gizzard shad, which was the dominant species from the catch on the 11th March, might have affected this difference. The correlation between TS and other properties was very week. The significant difference seemed even small differences of average values because of the large data volume.