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        검색결과 74

        1.
        2024.04 구독 인증기관·개인회원 무료
        Rhaphidophoridae (Orthoptera: Ensifera), commonly known as cave crickets, are a wingless family and considered the most ancient lineage within Tettigoniidea. However, previous molecular phylogenetic studies and morphological hypotheses have shown inconsistencies. Although their fossils have been found in Baltic amber, their systematic placement remains unrevealed. This study reconstructed a comprehensive phylogeny integrating both extant and fossil lineages. Initially, we revealed relationships within extant lineages through molecular phylogenetics including all extant subfamilies for the first time. Subsequently, using a cladistic approach based on morphology, we confirmed the systematic position of fossil taxa †Protroglophilinae with a report of a new species. Integrating molecular and morphological phylogeney by total evidence tip-dating, we present the comprehensive phylogeny of Rhaphidophoridae considering both extant and fossil groups.
        2.
        2024.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Scanning probe microscopy (SPM) has become an indispensable tool in efforts to develop the next generation of nanoelectronic devices, given its achievable nanometer spatial resolution and highly versatile ability to measure a variety of properties. Recently a new scanning probe microscope was developed to overcome the tip degradation problem of the classic SPM. The main advantage of this new method, called Reverse tip sample (RTS) SPM, is that a single tip can be replaced by a chip containing hundreds to thousands of tips. Generally for use in RTS SPM, pyramid-shaped diamond tips are made by molding on a silicon substrate. Combining RTS SPM with Scanning spreading resistance microscopy (SSRM) using the diamond tip offers the potential to perform 3D profiling of semiconductor materials. However, damage frequently occurs to the completed tips because of the complex manufacturing process. In this work, we design, fabricate, and evaluate an RTS tip chip prototype to simplify the complex manufacturing process, prevent tip damage, and shorten manufacturing time.
        4,000원
        3.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the shape optimization of the injector according to fuel and tip was conducted through analytical techniques. As an analysis condition, a flow rate of 0.08 kg / s was applied to the inlet and the outlet was given a condition of 0 Bar. The working fluid for each fuel was applied. As a result of the analysis, it can be seen that the pressure and velocity of model with the modified tip become higher than that of the base model in diesel. Compared with the base model in the case of gasoline, the modified model of the tip was found to have more stable injection when the pressure inside the combustion chamber and the straightness of the fuel were observed. Finally, in case of LPG injector, the same modified tip as gasoline was found to be the more stable injection. On the basis of this study result, the shape parameters of the injector can be inferred.
        4,000원
        4.
        2019.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study discussed the effects of inclined interface location to apply the design of inclined interface of composite materials subjected to shear loading. The fracture parameters are analyzed by finite element method of ANSYS. As a results, If in case of the angle of inclination is 45 degrees, inclined interface is longer and the crack tip is closer, the less the crack suppression effect. If the inclined interface location is a more than twice the length of the inclined interface, the effect of suppressing crack propagation are constant regardless of the location. In case of the inclined interface is longer and the crack tip is closer, the cause of increase of energy release rate is a due to the increase of shear stress. If in case of the angle of inclination is 90 degrees, inclined interface is closer to the crack tip, the better the crack suppression effect. If the inclined interface location is a less than twice the length of the inclined interface, the effect of suppressing crack propagation are dominant. And if the inclined interface location is a more than twice the length of the inclined interface, crack suppression effect is gradually reduced.
        4,000원
        5.
        2019.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 균열선단 그리드 세분화기법을 소개하고 자연요소법을 이용한 균열해석에 이 기법을 적용함으로서 그 유효성을 고찰하였다. 유한요소법에 있어서의 국부적 h-세분화와 같이 높은 응력 특이성을 보이는 균열선단 주위를 따라 자연요소법 그리드를 국부적으로 세분화하였다. 본 논문에서 소개되는 그리드 세분화기법은 2단계로 구성되며, 1단계에서는 그리드 점들이 추가되고 2단계에서는 균열선단 절점을 공유하는 델라우니 삼각형들이 나뉘게 된다. 제안하는 그리드 세분화기법의 타당성과 균열해석에서의 유효성을 입증하기 위해 대칭 엣지 균열을 갖는 평면 변형률 상태의 사각 평판을 해석하였다. 수치해석 결과의 상대비교를 위해 균일한 자연요소 그리드를 이용한 균열해석도 수행하였으며, 균열선단이 세분화된 그리드는 균일한 그리드와는 달리 이론해와 조밀한 그리드와 유사한 균열선단 응력분포를 나타내었다. 또한, 총 그리드 절점수에 대한 해석결과의 전역 상대오차에서도 세분화된 그리드가 균일한 그리드에 비해 높은 수렴율 나타내었다.
        4,000원
        7.
        2017.05 구독 인증기관·개인회원 무료
        The acetyltransferase Tip60 (Kat5) is a member of the MYST family of HATs that was initially identified as a cellular protein. TIP60 acetylates histone and non-histone proteins, and is involved in diverse biological processes, including apoptosis, cell cycle, and DNA damage responses. In this study, a specific inhibitor of TIP60, Nu 9056, was used to study the function and its regulatory mechanism of Tip60 in the porcine preimplantation embryonic development. The results showed that inhibition of TIP60 impaired the embryonic development due to induce DNA damage through ATM-p53-p21 pathway, it was evidenced by expression of γH2A in the nuclei of blastocysts. In addition, TIP60 inhibition decreased efficiency of DNA repair by regulating P53 binding protein 1 expression. Furthermore, autophagy was induced following TIP60 inhibition through modulating microtubule-associated protein 1A/1B-light chain 3 expression. In conclusion, the results suggest that TIP60 plays a critical role in early embryonic development via regulation of DNA damage and its repairs.
        8.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to establish a propagation system by shoot tip culture of Hosta plantaginea ‘Joseon’, of which production has increased as landscape plants and cut foliage. We evaluated the effects of culture methods (drum shaker in liquid, filter paper bridge in liquid and solid media), media (1/2MS , 1MS, 2MS), cytokinin (BA, kinetin, TDZ), and light quality (fluorescent lamp, red LED, blue LED, red LED + blue LED) on shoot multiplication and rooting. In the treatment by culture methods, the highest number of shoots (2.4 shoots per explant) was obtained on liquid media with drum shaker (BA 4.0 mg·L-1+ NAA 0.2 mg·L-1) and solid medium (BA 4.0 mg·L-1+ NAA 0.2 mg·L-1), but the shoots showed vitrification symptoms in liquid media. In media treatment, underground growth was good in 1/2MS and 1MS: overground growth was good in 1MS and 2MS but shoot length of 2MS tended to be shortened. In the treatment by cytokinin, kinetin 2.0 mg·L-1+ NAA 0.2 mg·L-1 and k inetin 4.0 mg·L-1+ NAA 0.2 mg·L-1 showed the highest number of shoots (3.4 and 3.3 shoots per explant, respectively). In the treatment by light qualities, red LED showed the highest number of shoots, shoot length, leaf number, fresh weight, dry weight, and leaf area. Red LED enhanced shoot length elongation, but chlorophyll content was lower. The content of chlorophyll was highest in blue LED, but the number of the shoots was lower. Shoots were rooted easily on basa MS medium without NAA, showing 100% of rooting. As a result, it might be considered that roughly 6,561 plants can be produced through subculture for one year in vitro from only one shoot tip of H. plantaginea ‘Joseon’ in MS semi-solid medium with BA 4.0 mg·L-1+ NAA 0.2 mg·L-1 or with kinetin 4.0 mg·L-1+ NAA 0.2 mg·L-1.
        4,000원
        9.
        2015.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Fatigue crack growth experiments were carried out on a 304 L stainless steel compact-tension(CT) specimen under load control mode. Neutron diffraction was employed to quantitatively measure the residual strains/stresses and the evolution of stress fields in the vicinity of a propagating fatigue-crack tip. Three principal stress components (i.e. crack growth, crack opening, and through-thickness direction stresses) were examined in-situ under loading as a function of distance from the crack tip along the crack-propagation path. The stress/strain fields, measured both at the mid-thickness and near the surface of the CT specimen, were compared. The results show that much higher compressive residual stress fields developed in front of the crack tip near the surface than developed at the mid-thickness area. The change of the stresses ahead of the crack tip under loading is more significant at the mid-thickness area than it is near the surface.
        3,000원
        10.
        2015.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 Euler-Bernoulli Beam(EB-beam) 및 신속 Fourier 변환을 이용하여 수치분석적 빔 모델 및 Co-rotational plane beam EDISON program(CR-beam)을 이용한 빔 모델의 가진주파수 변화에 따른 외팔보의 자유단 진동 연구를 수행하였다. 위의 두 빔 모델에서의 끝단에서는 진동이 시간이 지남에 따라 감소하다가 정상상태에 이르는 것을 확인하였다. 끝단에서 가진주파수가 증가함에 따라 구조적 감쇠에 의해 변위이 감소하는 경향을 보인다. 감쇠를 고려한 EB-beam과 CR-beam가 정상상태로 진입하는 경향이 비슷하나, 가진주파수는 정상상태가 나타나는 시간과 독립적임을 제시한다.
        4,000원
        11.
        2015.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 구조물에 작용하는 하중의 크기와 진동수에 따른 거동의 비선형성을 확인하고 정확한 예측을 위한 방법을 모색하기 위하여 외팔보의 정적 및 동적해석의 수행에서 선형, 비선형 해석의 결과를 비교하는 연구를 진행하였다. 우선 보의 자유단에 수직방향의 정적 및 동적 하중을 가한 상황을 예측하였다. 선형 해석방법으로 고전 외팔보 이론을 적용하였고, co-rotational dynamic 유한요소해석 기법을 개발하여 비선형 해석방법으로 사용하였다. 먼저 정적해석에서 외력의 크기가 달라질 때 선형 및 비선형 해석 예측이 어떠한 차이를 보이는지 비교하였다. 그리고 동적해석을 통해 가진 진동수의 변화에 따른 보 끝단의 무차원화된 변위의 양상을 연구하였고, 공진진동수 근방에서의 상당한 변위가 발생함을 보였다. 마지막으로 주파수 지연현상을 조사하기 위해 특정 진동수에서의 시간 경과에 따른 보의 변위를 확인하였다.
        4,000원
        12.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Tool tips of the circular saw for the steel cutting have commonly applied to brazing type welded the saw body to tips. In this case, when the tool tip is required to the exchange, many problems were occurred as the exchange cost is high and its time is long. In this study, to resolve the brazing type circular saw, the insert type circular saw has designed and made. Also, to confirm the performance of new type circular saw, the various experiments were carried out under condition of tip's shape and machining conditions.
        4,000원
        13.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The hydrofoil-tip mixer can be used to create the desired material by mixing the two materials in various industries, especially in the waste water and sewage water treatment. The purpose of this study is to clarify flow characteristics induced by 3 types impellers in a mixing tank by CFD. In this study, flat plate, hydrofoil and hydrofoil-tip type impellers are used and the rotating speeds of impellers are 25, 35, 45 rpm. The results in present study show that hydrofoil-tip type is the most proper impeller for mixing in the waster water treatment tank and reducing required power of rotating impeller. This results can be used for the design of the mixing tank in the waste water treatment system.
        4,000원
        14.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 그래핀의 모드 I 균열 진전에 대한 분자동역학 해석과 수치보조장을 사용하는 영역 투영 방법의 역문제 해석방법을 결합하여 균열 선단 응집 법칙을 평가하는 효율적인 방법을 제시하고 있다. 그래핀의 균열 선단 응집 법칙을 결정하는 것은 균열 선단에서 멀리 떨어진 영역의 변위를 사용하여 균열 면에서 미지의 응집 트랙션과 열림 변위를 구하는 역문제를 해석해야 하는데 상호 J-적분과 M-적분의 경로 보존성과 효율적인 수치보조장을 사용하는 방법을 적용하였다. 분자동역학 해석에서 원자 변위를 유한요소 절점 변위로 이동최소자승법을 사용하여 근사하였으며 안정적인 역문제 해석을 통하여 원자 단위의 거동을 연속체 해석으로 연결시킬 수 있는 새로운 방법을 보여주었다.
        4,000원
        15.
        2013.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, by using nickel chloride solution as a raw material, a nano-sized nickel oxide powder with an average particle size below 50 nm was produced by spray pyrolysis reaction. A spray pyrolysis system was specially designed and built for this study. The influence of nozzle tip size on the properties of the produced powder was examined. When the nozzle tip size was 1 mm, the particle size distribution was more uniform than when other nozzle tip sizes were used and the average particle size of the powder was about 15 nm. When the nozzle tip size increases to 2 mm, the average particle size increases to roughly 20 nm, and the particle size distribution becomes more uneven. When the tip size increases to 3 mm, particles with an average size of 25 nm and equal to or less than 10 nm coexist and the particle size distribution becomes much more uneven. When the tip size increases to 5 mm, large particles with average size of 50 nm partially exist, mostly consisting of minute particles with average sizes in the range of 15~25 nm. When the tip size increases from 1 mm to 2 mm, the XRD peak intensities greatly increase while the specific surface area decreases. When the tip size increases to 3 mm, the XRD peak intensities decrease while the specific surface area increases. When the tip size increases to 5 mm, the XRD peak intensities increase again while the specific surface area decreases.
        4,000원
        17.
        2013.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, using a tin chloride solution as the raw material, a nano-sized tin oxide powder with an average particle size below 50 nm is generated by a spray pyrolysis process. The properties of the tin oxide powder according to the nozzle tip size are examined. Along with an increase in the nozzle tip size from 1 mm to 5 mm, the generated particles that appear in the shape of droplets maintain an average particle size of 30 nm. When the nozzle tip size increases from 1 mm to 2 mm, the average size of the generated particles is around 80-100 nm, and the ratio of the independent particles with a compact surface structure increases significantly. When the nozzle tip size is at 3 mm, the majority of the generated particles maintain the droplet shape, the average size of the droplet-shaped particles increases remarkably compared to the cases of other nozzle tip sizes, and the particle size distribution also becomes extremely irregular. When the nozzle tip size is at 5 mm, the ratio of droplet-shaped particles decreases significantly and most of the generated particles are independent ones with incompact surface structures. Along with an increase in the nozzle tip size from 1 mm to 3 mm, the XRD peak intensity increases, whereas the specific surface area decreases greatly. When the nozzle tip size increases up to 5 mm, the XRD peak intensity decreases significantly, while the specific surface area increases remarkably.
        4,000원
        18.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As the increase of chrysanthemum demand on chrysanthemum increases in Korea, the production of high quality chrysanthemum is needed. Chrysanthemum stunt viroid (CSVd) is one of the important viroid, which infects chrysanthemum and induces diseases that affects the decrease of quality and yield. To solve this problem, we used different size of meristem of chrysanthemum ‘Ency’ for shoot tip culture and also that of combined with heat treatment at 37οC. The efficiency of CSVd elimination was influenced by the size of shoot tip. The small-sized of meristems with 1 or 2 leaf primodia were regenerated into the highest number of CSVd-free plantlets. By RT-PCR, the 214-bp band corresponding to CSVd was not detected in 22.2% of the total number of tested regenerants from shoot tips with 2 leaf primordia. While, shoot tip culture combined with heat treatment of one-month-old in vitro shoots was not effective for CSVd-elimination. The CSVd-free plants grew more vigorously than CSVd-infected plants in the greenhouse.
        4,000원
        19.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The enzyme invertase contributes to sugar unloading, pathogen defense, differentiation and development in plants. We cloned the complete cDNA of a soluble acid invertase from pea seedlings (Pisum sativum) via RT-PCR and the rapid amplification of the cDNA
        4,000원
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