아가로스 겔 전기영동에서 간단하고 실용적인 DNA 염색 방법

박성환(Seong-Whan Park) 한국산업기술융합학회(구. 산업기술교육훈련학회) 2022 산업기술연구논문지 (JITR) Vol.27 No.4

핵산 염색시약은 아가로스 겔 전기영동에서 DNA 밴드를 관찰하기 위해 필요하다. 전통적인 염색법은 겔 전기영동이 끝난 후 염색하는 post-staining 방법이지만, 편리한 대안으로 겔에 염색시약을 첨가하는 pre-cast 염색법이 사용되어 왔다. 또 다른 염색 방법으로 염색시약을 아가로스 겔이 아닌 6X 로딩 버퍼에 첨가하는 pre-load 염색법이 있다. Pre-load 염색법은 가장 간단하고 시간을 절약할 수 있는 방법이지만, 동일한 겔 내에서 DNA 밴드의 이동성이 차이를 보일 가능성이 있다. 본 연구에서는 염색시약이 혼합된 Midori Green Direct, GRGreen DNA loading buffer, ENVISION DNA dye loading buffer 등 상용의 loading buffer를 사용할 때, DNA 이동성에 변화가 나타나는 것을확인하였다. 반면에 250X GelRed®를 함유한 자체제작 6X 로딩 버퍼는 다양한 실험 조건에서도 이동성의 변화를나타내지 않았다. 마찬가지로, Shinystar와 EcodyeTM가 포함된 6X 로딩 버퍼 또한 안정적인 이동성을 보여주었다. 결론적으로, pre-load 염색법은 일상적인 겔 전기영동 작업에서 편리하고 실용적인 염색방법이 될 수 있으며, 250X GelRed®를 함유한 자체제작 6X 로딩 버퍼는 pre-load 염색에 있어 유용한 해결책이 될 수 있다. Nucleic acid staining dyes are necessary for the visualization of DNA bands in agarose gel electrophoresis. The conventional staining method follows a post-staining protocol that follows gel electrophoresis; pre-cast staining is used as a convenient alternative. Pre-load staining is another method in which a staining dye is added to the 6X loading buffer, and not in the agarose gel. Pre-load staining is simple and time-saving; however, it could alter the mobility of DNA bands within the same gel. In this study, the mobility alteration owing to the use of commercial pre-mixed loading buffers, such as Midori Green Direct, GRGreen DNA loading buffer, and ENVISION DNA dye loading buffer, were evaluated. Lab-prepared 6X loading buffer containing 250X GelRed®dye did not alter the mobility under various experimental conditions. Similarly, 6X loading buffer containing Shinystar and EcodyeTMdid not affect mobility. In conclusion, pre-load staining method is a convenient and practical staining method for routine gel electrophoresis; lab-made 6X loading buffer containing 250X GelRed®could be used for pre-load staining.

수치해석을 통한 흙막이벽체 버팀보의 최적 선행하중 산정에 관한 연구

문인종(In Jong Moon),장승주(Seung Ju Jang),이강일(Kang Il Lee) 한국지반신소재학회 2021 한국지반신소재학회 논문집 Vol.20 No.2

지하공간의 활용이 활성화됨에 따라 지중구조물의 설치를 위해 깊은 굴착이 이루어지고 있으며, 굴착지반의 변형을 최소화하기 위해 흙막이벽체가 많이 활용되고 있다. 특히 도심지에서의 깊은 굴착이 진행함에 따라 벽체에 인접한 구조물의 피해가 발생하지 않도록 벽체 변형을 최소화하기 위한 방법들이 강구되어 왔으며, 이들 방법 중 하나가 버팀 선행하중 공법이다. 이 공법은 벽체의 버팀에 주동적으로 하중을 가해 벽체 변형을 억제하는 방법으로, 최근까지 이 공법에 관한 연구가 진행되어 왔다. 그러나 관련된 연구가 활발히 진행되었음에도 불구하고, 현재까지 선행하중에 대한 명확한 관리기준이 마련되어 있지 않다. 또한 굴착 깊이가 깊거나 배면지반의 상태에 따라 버팀의 작용력이 증가할 수 있으므로, 버팀에 가할 수 있는 선행하중의 크기가 감소할 수 있다. 그럼에도 불구하고 기존 연구결과에서 제안하고 있는 선행하중의 크기(작용하중의 50%이상)를 버팀에 일률적으로 적용하고 있다. 본 연구에서는 벽체의 배면지반조건에 따른 H-빔 버팀보의 선행하중 적용범위를 평가하고자 3차원 유한요소해석을 수행하였다. 해석결과, 연약한 지반조건이고 깊은 심도 굴착이 진행하는 경우 토압과 선행하중에 의한 버팀구조의 안정성에 문제가 발생할 가능성이 매우 큰 것으로 나타났다. 그리고 선행하중의 적용범위는 버팀 작용하중의 5%∼70%인 것으로 나타났다. As the utilization of the underground space is activated, deep excavation of ground has been conducted for the installation of underground structures, the earth retaining wall has widely used to minimize deformation of the excavated ground. In particular, as deep excavation is actively progressing in an urban area where structures are concentrated, methods to minimize the deformation of wall have been devised to prevent damage to the structure adjacent to the wall, and one of these methods is the pre-loading method. This method is a method of suppressing the deformation of wall by actively applying a load on the strut to be installed in wall, and research on this method has been conducted recently. However, although related studies have been actively conducted, the management standard for the pre-loading of bracing has not been clearly presented until now. In addition, since the working force in the strut may increase depending on the depth of excavation or the soil condition of the backfill, the magnitude of the pre-loading that can be applied to the brace may decrease. Nevertheless, the magnitude of the pre-loading (more than 50% of the working load) proposed by the previous research results has been uniformly applied to the strut. In this study, 3D finite element analysis was performed to evaluate the application range of the pre-loading of H-beam strut according to the soil conditions of backfill. As a result of the analysis, it was found that there is a very high possibility that a problem may occur in the stability of the structure of strut due to the earth pressure and the pre-loading when the soil condition is weak and deep excavation proceeds. And it was found that the application range of the pre-loading was 5%∼70% of the working load in strut.

Study on load distribution ratio of composite pre-tightened tooth joint by shear nonlinearity

Yifeng Gao,Fei Li,Qilin Zhao,Jiangang Gao,Lin Shi,Zhiqin Zhao 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.5

Load distribution has a great influence on the mechanical properties of composite pre-tightened multi-tooth connection. To obtain the load distribution mechanism of composite pre-tightened multi-tooth joints, the multi-tooth joints were studied by experimental and theoretical methods. First, an experimental study was conducted on three-tooth specimens with different tooth depths and tooth lengths, and the failure mode, bearing capacity and load distribution mechanism of the specimens were obtained. Then, based on the nonlinear constitutive of interlaminar shear, an analytical model for load distribution of composite pre-tightened multi-tooth joint was proposed to research the multi-tooth load distribution mechanism. Finally, the theoretical and experimental results were compared. The research showed: (1) The theoretical results of the multi-tooth load distribution ratio were in good agreement with that of the experimental results, the maximum error between the theoretical value and the experimental value of the three-tooth joint was 17.44%, and the minimum error was only 2.35%; (2) The load distribution ratio of composite pre-tightened multi-tooth was uneven, for three-tooth joints, the values of load distribution ratio from large to small were: the first tooth, the third tooth and the second tooth.; (3) Multi-tooth load distribution ratio changed with the change of external load. The change of load distribution ratio was obvious in the early stage of loading, and tended to be gentle in the later stage of loading.

매입말뚝의 선단지지력 증대를 위한 강관 부착 PHC파일 개발

백규호,양희정 한국지반공학회 2013 한국지반공학회논문집 Vol.29 No.8

Bored pre-cast piles using PHC piles is widely used in foundation of building structures constructed in urban areas because noise and vibration due to pile installation are low. However, since slime is formed at the base of borehole and the density of bearing stratum surrounding the base of borehole is decreased due to stress relaxation in drilling process of bored pre-cast pile method, the base load capacity of bored pre-cast piles is very low compared to the strength of bearing stratum. In this study, a new type of PHC pile, which short steel pipe with the same diameter as the PHC pile is attached to the pile tip, is developed to increase the base load capacity of bored pre-cast piles. In order to check the effect of the use of new PHC pile on the base load capacity of bored pre-cast piles, field pile load tests are performed for bored pre-cast piles using the new and existing PHC piles. Results of the pile load tests show that the new PHC pile gives higher base load capacity to bored pre-cast piles than the existing PHC pile, since the tip of new PHC pile is penetrated to undisturbed bearing stratum passing through the slime at the base of borehole and the loosened bearing stratum under the slime by pile driving using light hammer.

근접 굴착시 흙막이벽 버팀대 선행하중 재하에 따른 터널의 거동

김일,이상덕 한국지반공학회 2007 한국지반공학회논문집 Vol.23 No.10

A New pre-loading system, through which a large pre-load could be charged was developed and applied to the braced wall in order to stabilize the adjacent tunnel. A pre-load larger than the designated axial force of bracing was imposed to prevent the horizontal displacement of the braced wall during the ground excavation. For this purpose, real scale model tests (1/10) were conducted, without and with pre-load on braced wall. And numerical analyses were performed for both the cases without and with pre-load, which were half (50%) and full (100%) respectively, and larger scale of the design axial force of bracing. FEM program called PLAXIS was used for numerical analysis. As a result, it was found that the stability of the existing tunnel adjacent to the braced wall could be greatly enhanced when the horizontal displacement of braced wall was reduced by applying a pre-load, which was larger than the designated axial force of bracing.

Evaluation of pre-stresses in the menisci of human knee joint using microindentation

Kwak, Dai Soon,Bae, Ji Yong,Kim, Sung Youb,Jeon, Insu,Lu, Tian Jian Professional Engineering Publishing Ltd. 2014 Proceedings of the Institution of Mechanical Engin Vol. No.

<P>To evaluate the pre-stress in the menisci of a human knee joint, the technique of microindentation was adopted. Five specimens each for lateral and medial menisci attached to the tibia were prepared from the knee joints of Korean cadavers to represent the pre-stress state of the meniscus. To create test specimens for the stress-free state of the meniscus, each meniscus was resected from the tibia and cut into three parts, which were subsequently attached to a metal plate. Indentations were carried out in each meniscus in both the pre-stress state and the stress-free state. The pre-stresses in the menisci were evaluated using the load-versus-depth curves. Compressive pre-stresses were found in the menisci. For each indentation region, the pre-stresses in the medial meniscus were higher than in the lateral meniscus. The highest pre-stress in both the lateral and medial meniscus was found in the posterior regions, while the anterior regions experienced the lowest pre-stress. The obtained pre-stresses can be used for the accurate numerical analysis, the fabrication of artificial menisci, and the diagnosis of meniscal disease progression for human knee joints.</P>

쏘일네일링과 앵커가 결합된 하이브리드 공법의 하중전이 메커니즘

서형준,김현래,한신인,이인모 한국지반공학회 2012 한국지반공학회논문집 Vol.28 No.1

The load transfer mechanism of hybrid model of soil-nailing and compression anchor is studied in this paper. The hybrid model is composed of an anchor bar (installed at the tip) with two PC strands and a steel bar. It can make active behavior of skin friction by applying the pre-stress. In this paper, the load transfer mechanisms of soil-nailings, compression anchors, and hybrid models, respectively, are obtained from skin friction theory and load transfer theory. Field pullout tests are performed to identify the load transfer mechanism and experimental results are compared with analytical solution. In case of soil-nailings, the tension load is transferred from face to tip, however, in case of compression anchors, the compression load is transferred from tip to face. The experimental behavior of the hybrid model is similar to that of compression anchor when only pre-stress is applied. If the pullout test is performed by simultaneously pulling out the anchor and the nail, the compression load is dominant at the tip and tension load is dominant at the face. The load transfer mechanism of the hybrid model shows the combined behavior of soil-nailings with compression anchors.

Pre-processing of load data of agricultural tractors during major field operations

Myong-Jin Ryu,Md. Shaha Nur Kabir,Youn-Kug Choo,Sun-Ok Chung,Yong-Joo Kim,Jong-Kyou Ha,Kyeong-Hwan Lee 충남대학교 농업과학연구소 2015 농업과학연구 Vol.42 No.1

Development of highly efficient and energy-saving tractors has been one of the issues in agricultural machinery. For design of such tractors, measurement and analysis of load on major power transmission parts of the tractors are the most important pre-requisite tasks. Objective of this study was to perform pre-processing procedures before effective analysis of load data of agricultural tractors (30, 75, and 82 kW) during major field operations such as plow tillage, rotary tillage, baling, bale wrapping, and to select the suitable pre-processing method for the analysis. A load measurement systems, equipped in the tractors, were consisted of strain-gauge, encoder, hydraulic pressure, and radar speed sensors to measure torque and rotational speed levels of transmission input shaft, PTO shaft, and driving axle shafts, pressure of the hydraulic inlet line, and travel speed, respectively. The entire sensor data were collected at a 200-Hz rate. Plow tillage, rotary tillage, baling, wrapping, and loader operations were selected as major field operations of agricultural tractors. Same or different farm works and driving levels were set differently for each of the load measuring experiment. Before load data analysis, pre-processing procedures such as outlier removal, low-pass filtering, and data division were performed. Data beyond the scope of the measuring range of the sensors and the operating range of the power transmission parts were removed. Considering engine and PTO rotational speeds, frequency components greater than 90, 60, and 60 Hz cut off frequencies were low-pass filtered for plow tillage, rotary tillage, and baler operations, respectively. Measured load data were divided into five parts: driving, working, implement up, implement down, and turning. Results of the study would provide useful information for load characteristics of tractors on major field operations.

CFS로 보수된 RC보의 파괴에서 사전균열의 영향

김충호,고신웅 경성대학교 공학기술연구소 2005 공학기술연구지 Vol.12 No.-

This investigation performed monotonic incremental loading test and repeating loading test of the beams repaired with Carbon Fiber Sheet(CFS) after occurring the crack corresponding to 0.75P_(y) representing the damages. Experiments confirmed that growth of the special pre-crack under the loading point was a direct cause of a delamination of the CFS and it led a failure of the beams. From the test results, it is concluded that the failure of beams repaired by CFS will occur at pre-crack under the loading point.

Flexural Behavior of RC Beams Strengthened with Steel Plates/Carbon Fiber Sheets(CFS) under Pre-Loading Conditions

Shin, Yeong-Soo,Hong, Geon-Ho Korea Concrete Institute 2000 KCI concrete journal Vol.12 No.1

The reinforced concrete(RC) flexural members strengthened with steel plate/CFS at soffit have initial stresses and strains in reinforcements and concrete caused by the service loads at the time of retrofitting works. These initial residual stresses and strains of strengthened beams may affect the flexural performance of the rehabilitated beams. The objective of this study is to evaluate and verify the effectiveness of rehabilitation by external bonded steel plates and CFS to the tension face of the beams under three conditions of pre-loading. Thirteen beam specimens are tested and analyzed. Main test parameters are pre-loading conditions, strengthening materials and reinforcement ratio of specimens. The effect of test parameters on the strengthened beams is analyzed from the maximum load capacity, load-deflection relationship, state of stress of the materials. crack propagation phase, and failure modes. Both test results and design formulas of ACI Code provisions are compared and evaluated.