포토리소그래피는 웨이퍼 위에 선폭 10나노 이하의 패턴을 올리는 반도체 제조 공정의 핵심 기술이며 선폭을 줄이고 불량을 줄이기 위하여 photo-resist 용 액 제조 및 정제 기술이 상당한 수준에 올라와 있지만 아직고 soft particle 정제를 위한 공정을 시도되고 있다. 현재 개발되어 있는 필터는 soft particle 정제 기술이 상당히 미흡한 수준이다. 나일론이나 폴리에틸렌 위에 아라미드 고분자 를 함침하여 soft particle 정제 특성을 살펴보았다. 또한 팔라듐 나노입자를 합성하여 투과 특성에 사용하였다.
The construction industry has the characteristics of a rapid change in the working environment compared to the general industry, and there will be a high risk of accidents in the process of accommodating workers in these working environments.Also, the severity of the accident is higher if the accident occurs in the event of a significant and hazardous operation than other industries.Safety and safety management of the workplace is the Occupational Safety and Health Act of the Ministry of Business and Safety.
In this study, the heat transfer characteristics of pilot wave heat exchanger for white smoke reduction system was investigated. The performance of the wave and honeycomb heat exchanger combined with the first stage, second stage and third stage was tested using a calorimeter. Air and water inlet/outlet temperature and flow rate, pressure drop and dehumidification amount were measured to compare the heat transfer performance according to the type and the combination of heat exchanger. The heat transfer rate and dehumidification amount of the wave heat exchanger were higher than that of the honeycomb heat exchanger, and the pressure drop was low. As the stage increased, the heat transfer rate and the increase of the dehumidification amount were more pronounced, and the pressure drop linearly increased. The wave heat exchanger had a lower flow resistance than the honeycomb heat exchanger with the honeycomb structure and had a higher heat transfer effect due to the convection, so the water outlet temperature was higher in the wave heat exchanger.
The addition of a large amount of alloying elements reduces the compactibility and increases the compacting pressure, thereby shortening the life of the compacting die and increasing the process cost of commercial PM steel. In this study, the characteristic changes of Fe-Mo-P, Fe-Mn-P, and Fe-Mo-Mn-P alloys are investigated according to the Si contents to replace the expensive elements, such as Ni. All compacts with different Si contents are fabricated with the same green densities of 7.0 and 7.2 g/cm3. The transverse rupture strength (TRS) and sintered density are measured using the specimens obtained through the sintering process. The sintered density tends to decrease, whereas the TRS increases as the Si content increases. The TRS of the sintered specimen compacted with 7.2 g/cm3 is twice as high as that compacted with 7.0 g/cm3.
In this study we manufacture a Ni-Cr-B-Si +WC/12Co composite coating layer on a Cu base material using a laser cladding (LC) process, and investigate the microstructural and mechanical properties of the LC coating and Ni electroplating layers (reference material). The initial powder used for the LC coating layer is a powder feedstock with an average particle size of 125 μm. To identify the microstructural and mechanical properties, OM, SEM, XRD, room and high temperature hardness, and wear tests are implemented. Microstructural observation of the initial powder and LC coating layer confirm the layer is composed mainly of γ-Ni phases and WC and Cr23C6 carbides. The measured hardness of the LC coating and Ni electroplating layers are 653 and 154 Hv, respectively. The hardness measurement from room up to high temperatures of 700°C result in a hardness decrease as the temperature increases, but the hardness of the LC coating layer is higher for all temperature conditions. Room temperature wear results show that the wear loss of the LC coating layer is 1/12 of the wear level of the Ni electroplating layer. The measured bond strength is also greater in the LC coating than the Ni electroplating.
본 연구에서는 온실을 운영하고 있는 농장주를 대상으로 영농작업기록장(농가경영기록장 또는 농가작업일지)의 작성 실태, 활용도 및 작성 상의 애로 사항을 설문지를 이용하여 조사한다. 논문의 목적은 조사된 내용을 분석하여 기존 영농작업기록장의 애로 사항을 도출하고 기록장의 활용방안 제안하는 것이다.
As a system complexity increases and technology innovation progresses rapidly, it tends to lease a system rather than own one. This paper deals with a decision-making model to determine the preventive maintenance strategy for leased equipment. Various maintenance options are presented and formulated via the non-homogeneous Poisson process. During the lease period, the preventive maintenance strategy that minimizes the total cost among the presented maintenance options is selected. A numerical example is provided to illustrate the proposed model.
This paper describes the Bayesian and non-Bayesian approach for reliability demonstration test based on the samples from a finite population. The Bayesian approach involves the technical method about how to combine the prior distribution and the likelihood function to produce the posterior distribution. In this paper, the hypergeometric distribution is adopted as a likelihood function for a finite population. The conjugacy of the beta-binomial distribution and the hypergeometric distribution is shown and is used to make a decision about whether to accept or reject the finite population. The predictive distribution of the beta-binomial distribution is shown and will be used for the reliability demonstration test. A numerical example is also given.
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.
This study was applied to the PCA (Primary Components Analysis) for the sixteen table setting at the 2017 Yeongju local food contest. In this contest, we have developed a seonbibansang and a temple one-dish meal. As a result of the correlation analysis, the applicability and composition were 0.7980, harmony and taste were 0.7747 and easiness and composition were 0.7435. In the Primary Component Y1, all the variables X1…X10 mean that the quality of the food had positive values greater than zero. The second Primary Component Y2 has a large positive value while X4, X5, X6, X7, X9 have negative values. Y2 is a value representing the sanitation variable, and can be considered a traditional and characteristic table setting natural to the native food in Yeongju. In addition, we developed an-hyangbansang and seonmyoaecheong food content by applying PCA factors (the elements of harmony, ease and sanitation). Table setting of an-hyangbansang provided energy 61.5%, protein 20.0% and fat 18.5% and seonmyoaecheong provided energy 62.7%, protein 15.4% and fat 22.2%. This satisfied the necessary amount of caloric nutrient intake that could be provided in a meal. Especially through story-telling, a modern interpretation - or rebranding - of local and traditional foods could make these traditional food products familiar to consumers currently. The developed table setting is felt to be conductive to the possible commercialization and introduction of traditional food into the mainstream commercial food service industry.
Palatability and texture analysis of nine Korean rice cultivars were investigated to select the most appropriate rice variety for the cooked-rice processing. The rice cultivars studied consisted of Samkwang, Seonpum, Wolbaek, Andabyeo, Dasan-1, Ilpum, Haiami, Jungsanggold and Chindle. They revealed the moisture, protein, amylose and starch contents of 10~12, 5~6, 12~19, and approximately 90%, respectively. Among the evaluated rice varieties, WB exhibited the lowest amylose content (12.7%) and Jungsanggold the next (17.2%). In the rapid-visco analyzer test, Jungsanggold, Chindle, Wolbaek and Seonpum revealed a low value of final and setback viscosities than other varieties. Using a toyo meter analyzer, Chindle, Haiami, Samkwang were selected as having high toyo palatability values, while Dasan-1, Wolbaek and Andabyeo revealed low values. Toughness and adhesiveness of all nine cooked rice varieties were highest in Jungsanggold, Chindle and Ilpum. Also, palatability of cooked rice was highest in the following order: Chindle (80.03) > Samkwang (76.21) > Jungsanggold (74.08). The results of this study suggest that Chindle may be effectively used to produce processed cooked rice.
Application Specific Messages(ASM)은 다수 선박들의 AIS사용으로 인한 통신 과부하 문제를 해결하기 위해 IMO, ITU, IALA와 같 은 국제기구들에 의해 해상에서의 적용이 결정되었다. ASM을 이용한 통신은 기상 정보, 사고보고 및 항해 경고를 포함하여 해양에서 많 은 양의 안전 관련 정보를 전송할 수 있다. 특히 ASM통신 시스템은 음성을 통한 선박 간, 선박과 육상 간(4S) VHF통신의 일부를 메시지 로 전달이 가능할 것으로 기대된다. 해상의 4S통신에서 중요도가 높은 문장을 표준통신메시지로 선정하여 ASM통신에 이용한다면, 정확 하고 신속한 메시지의 송수신이 가능할 것이다. 표준통신메시지의 결정은 사용자의 의견이 적극적으로 반영되어야 하며, 이를 위해 본 연 구에서는 57명의 항해사와 50명의 Vessel Traffic Service(VTS) 관제사를 대상으로 설문을 실시하였다. 설문의 결과를 분석하여 해상통신에 서 사용빈도가 높은 53개의 표준통신메시지를 제시하였다. 제시된 표준통신메시지는 해상에서 사용되는 주요 문장들에 대한 실제적인 정 보이며, ASM을 이용한 통신장비 및 인터페이스 개발을 위한 참고 자료로 이용될 수 있을 것이다.
In recent years there have been large increases in the hydraulic loading rates used to design dissolved air flotation (DAF) facilities for drinking water applications. High rate DAF processes are now available at loading rates of 20 to 40 m3/m2·h. This research evaluated dissolved air flotation as a separation method for algae and organic compounds from water treatment plants. During the service period of 2016. 5. to 2017. 6., DAF pilot plants (500 m3/day) process has shown a constantly sound performance for the treatment of raw water, yielding a significantly low level of turbidity (DAF treated water, 0.21~1.56 NTU). As a result of analyzing the algae cell counts in the influent source, it was expressed at 100-120 cells/mL. In DAF treated water, the removal efficient of alge cell counts was found to be upto 90%. The stable turbidity and algae removal were confirmed by operating the high rate DAF process under the condition of the surface loading rate of 30 m3/m2·hr.
In this study, we divided the process operation scenarios into three categories based on raw water temperature and turbidity. We will select and operate the process operation scenario according to the characteristics of the raw water. The number of algae in the DAF treated water has been analyzed to be less than 100 cells/mL. These results indicated that the DAF process is effective in removing the algae. In addition, the scenario of the integrated management decision algorithm of the DAF process was developed. DAF pilot plants (500 m3/day) process has shown a constantly sound performance for the treatment of raw water, yielding a significantly low level of turbidity (DAF treated water, 0.21~1.56 NTU).
This study evaluated how fresh pear cognition variables influences the purchase of primary and secondary products to promote pear consumption. The survey was performed online using 200 consumers who have consumed pears. Consumers’ cognition was classified into two groups, one that was more favorable toward fresh pears and one that was less favorable. The cognition toward pear significantly affected the attitude (p<0.001) and purchase intention (p<0.001) toward fresh pear. When consumers bought fresh pear, sweetness was most important among the selection attributes to both groups, and the most common reason why consumers liked the pear analyzed by check all that apply (CATA) was also sweet taste. However, the negative group did not prefer fresh pear because of taste and texture, so those qualities should be wellcontrolled. In addition, cognition toward primary products influenced liking and purchase intention of processed pear products, especially beverages (p<0.001), bakeries and sweets (p<0.05). Therefore, these types of secondary products should be developed based on consumers’ demands.
결합 기반 페리다이나믹 모델은 취성재료의 동적파괴 해석에 많이 이용되고 있으며, 최근의 연구(Bobaru et al., 2012)를 통해 적층유리 구조물의 동적 파괴 패턴 분석에도 활용되었다. 특히 실험(Bless et al., 2010)에서 나타난 적층유리 구조물의 다양한 손상 형태(압축 영역, Floret, Hertz-type 균열 등)를 결합 기반 페리다이나믹 시뮬레이션을 이용하여 구현하였다. 그 러나 실제 적층 구조물은 각 유리판 사이를 탄성이 있는 층간 재료로 결합하는 반면, 기존의 페리다이나믹 수치 시뮬레이션 에서는 층간 재료 결합을 무시하고 각 유리판이 직접 결속되도록 가정하여 층간 재료 효과가 무시되었다. 본 연구에서는 페 리다이나믹 층간 재료 모델링을 통해 실제 적층 구조물에 보다 근접한 페리다이나믹 수치 해석 모델을 제안한다. 일반적으 로 층간 재료는 매우 얇기 때문에 층간 재료를 명시적으로 모델링할 경우 많은 해석시간과 메모리가 소모되어 비효율적이 다. 따라서 본 연구에서는 명시적 모델링을 대신하여 가상 절점을 통해 층간 재료를 모델링한다. 수치 예제를 통해 제안된 층간 재료 모델링의 효율성 및 정확성을 검토한다. 또한 압축 상태의 적층 구조물 해석을 위해 단거리 상호작용력에 기반한 투과 방지 기법을 도입하고 파라미터 테스트를 통해 검증한다.
섬유강화 복합재료는 열팽창 계수의 방향성을 갖고 있을 뿐만 아니라 제작과정 온도와 실제 사용온도 사이의 차이 때문에 필연적으로 열응력 효과를 받게 된다. 이러한 열응력에 의한 파손현상은 실제 항공우주산업에서의 응용이 증대되고 있는 두 꺼운 복합 적층판의 경우에 더욱 현저한 현상으로 적층판의 역학적 기능 및 파단강도에 큰 영향을 미치게 된다. 본 연구에서 는 복잡한 재질로 구성되고 높은 세장비를 가진 블레이드 날개 구조의 차원축소 및 열 응력 복원 이론을 소개하고 3차원 유 한요소모델과 비교결과를 통해 효율성과 정확성을 입증한다. 또한 차원을 축소한 모델링을 구성하고 복원이론를 이용하여 열적 환경에 적용된 복합재 보 단면의 열응력을 차원 복원하고 시각적으로 형상화하는 효율적인 복원해석 과정을 소개하고 자 한다.
Styela clava (SC), a sea squirt has a biphasic life cycle, showed the animal phase during larval life and the vegetable phase during adult life. The adult SC becomes fixed on hard surface and covered with thick cellulose membrane to protect itself from various physical and chemical damages in marine environment. Especially, adult SC forms a huge cystic space as a portion of digestive tract, filled with seawater containing various planktons. In the present study, it is hypothesized that SC can produce secretory materials, like saliva in mammals, to sterilize, to neutralize, and to digest the cystic fluid. First of all, the cyst fluid was examined for the antimicrobial property by bacteria killing assay (BKA) using E. coli, and it resulted that the cyst fluid showed relatively weak bactericidal effect. The cyst fluid was also examined for antioxidant property by DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2,2-azinobis-3-ethybenzthiazdine-6-sulphonic acid) assay, and resulted that the cyst fluid showed strong antioxidant effect comparable to ascorbic acid. The antioxidant materials of cyst fluid were found both in cationic and anionic groups separated by ion exchange column using SP and Q beads, and they were also heat resistant. The strong antioxidant property seems to be originated from the abundant carotenoid materials in the cyst fluid of SC. However, the strong antioxidant materials of the cyst fluid may play a role for the essential antioxidant in the digestive tract of SC. Furthermore, the cyst fluid of SC was examined using SNU-1 cancer cells for its anticancer property. The flow cytometry analysis showed that both of cationic and anionic materials purified from the cyst fluid showed strong anticancer effect on SNU-1 cells. Taken together, the cyst fluid of SC showed weak antimicrobial, but strong antioxidant property and marked anticancer properties in vitro experiment. Therefore, it is presumed that SCs can neutralize the various free radicals of seawater and also protect themselves from carcinogenic impacts in aggressive marine environment by various bioactve substances of their cyst fluid.
나무주사제의 약제처리 오류(중복처리 또는 천공 후 약제 미처리)로 인한 방제예산의 낭비를 방지하고, 나무주사1회 처리로 소나무재선충과 매개충인 솔수염하늘소를 동시에 방제할 수 있는 ‘시인성 (視認性) 나무주사제(Acetamiprid+Emamectin benzoate SL)’의 실용성을 검증하였다. 시인성 확보를 위해 발색보조제를 첨가한 나무주사제는약제 처리 후 약 1개월간 약제처리 여부를 확인할 수 있는 시인성을 확보하였으며, 소나무 수체 내 약제의 전달력및 잔류성은 기존 제품(발색보조제무첨가) 대비 비등 이상이었다. 특히 2월~5월 사이에는 나무주사 시기에 관계없이솔수염하늘소에 대한 약효가 우화종료시기인 7월말까지 지속되므로 나무주사 1회 처리로 소나무재선충과 솔수염하늘소를 동시에 방제 가능하여, 솔수염하늘소 성충우화기에 수관처리하는 살충제를 대체할 수 있을 것으로 판단된다.