• Steel and Composite Structures
• /
• 제28권5호
• /
• pp.629-639
• /
• 2018

In this paper, the vibroacoustic responses of baffled laminated composite sandwich flat panel structure under the influence of harmonic excitation are studied numerically using a novel higher-order coupled finite-boundary element model. A numerical scheme for the vibrating plate has been developed in the frame work of the higher-order mid-plane kinematics and the eigen frequencies are obtained by employing suitable finite element steps. The acoustic responses are then computed by solving the Helmholtz wave equation using boundary element method coupled with the structural finite elements. The proposed scheme has been implemented via an own MATLAB base code to compute the desired responses. The validity of the present model is established from the conformance of the current natural frequencies and the radiated sound power with the available benchmark solutions. The model is further utilized to scrutinize the influence of core-to-face thickness ratio, modular ratio, lamination scheme and the support condition on the sound radiation characteristics of the vibrating sandwich flats panel. It can be concluded that the present scheme is not only accurate but also efficient and simple in providing solutions of the coupled vibroacoustic response of laminated composite sandwich plates.

• 한국안전학회지
• /
• 제25권1호
• /
• pp.57-61
• /
• 2010

Formwork is a temporary structure that supports its weight and that of fresh concrete as well as construction live loads. Scaffoling is a temporary frame used to support people and material in the construction or repair of buildings and other large structures. It is usually a modular system of metal pipes, although it can be made out of other materials. Bamboo is still used in some Asian countries like China. The purpose of a working scaffold is to provide a safe place of work with safe access suitable for the work being done. In construction site, steel pipes are usually used as scaffolds. In this study, scaffolding systems which is changed according to sleeper and joist space were measured by buckling test. Buckling load of respective scaffolding system was analyzed by structural analysis program(MIDAS). Buckling load of scaffold with/without wall connection and footboard was got by test and structural analysis. According to these results，we know that scaffolding system of case 3 is suitable. Buckling load of scaffold with wall connection is higher than without wall connection. So wall connection is important in scaffoling systems. Footboard in the scaffolding systems is not effective against promotion of buckling load. Finally, the present study results will be used to design scaffolding systems safely in the construction sites.

• Journal of Microbiology and Biotechnology
• /
• 제16권9호
• /
• pp.1416-1421
• /
• 2006

We identified a gene encoding the N-acetylmuramoyl L-alanine amidase (amiB) of Vibrio anguillarum, which catalyzes the degradation of peptidoglycan in bacteria. The entire open reading frame (ORF) of the amiB gene was composed of 1,722 nucleotides and 573 amino acids. The deduced amino acid sequence of AmiB showed a modular structure with two main domains; an N-terminal region exhibiting an Ami domain and three highly conserved, continuously repeating LysM domains in the C-terminal portion. An amiB mutant was constructed by homologous recombination to study the biochemical function of the AmiB protein in V. anguillarum. Transmission electron microscopy (TEM) revealed morphological differences, and that the mutant strain formed trimeric and tetrameric unseparated cells, suggesting that this enzyme is involved in the separation of daughter cells after cell division. Furthermore, inactivation of the amiB gene resulted in a marked increase of sensitivity to oxidative stress and organic acids.

• Asian-Australasian Journal of Animal Sciences
• /
• 제24권7호
• /
• pp.1019-1025
• /
• 2011

Toll-like receptors (TLRs) play an important role in the recognition of invading pathogens and the modulation of innate immune responses in mammals. The TLR4 and TLR7 are well known to recognize the bacterial lipopolysaccharide (LPS) and single stranded (ssRNA) ligands, respectively and play important role in host defense against Gram-negative bacteria and ssRNA viruses. In the present study, coding exon fragments of these two TLRs were identified, cloned, sequenced and analyzed in terms of insertion-deletion polymorphism, within bovine TLRs 4 and 7, thereby facilitating future TLR signaling and association studies relevant to bovine innate immunity. Comparative sequence analysis of TLR 4 exons revealed that this gene is more variable, particularly the coding frame (E3P1), while other parts showed percent identity of 95.7% to 100% at nucleotide and amino acid level, respectivley with other Bos indicus and Bos taurus breeds from different parts of the world. In comparison to TLR4, sequence analysis of TLR7 showed more conservation among different B. indicus and B. taurus breeds, except single point mutation at 324 nucleotide position (AAA to AAM) altering a single amino acid at 108 position (K to X). Percent identity of TLR7 sequences (all 3 exons) was between 99.2% to 100% at nucleotide and amino acid level, when compared with available sequence database of B. indicus and B. taurus. Simple Modular Architecture Research Tool (SMART) analysis showed variations in the exon fragments located in the Leucine Rich Repeat (LRR) region, which is responsible for binding with the microbial associated molecular patterns and further, downstream signaling to initiate anti-microbial response. Considering importance of TLR polymorphism in terms of innate immunity, further research is warranted.

• 생명과학회지
• /
• 제27권9호
• /
• pp.1003-1010
• /
• 2017

Paenibacillus woosongensis의 유전체 부분 염기서열로부터 mannanase를 코드하는 것으로 유추되는 open reading frame을 중합효소연쇄반응으로 증폭하여 대장균에 클로닝하고 염기서열을 결정하였다. Mannanase 유전자는 man26AT로 명명하였으며 1,053 아미노산으로 구성된 단백질을 코드하는 3,159 뉴클레오티드로 이루어졌다. 아미노산 잔기배열을 분석한 결과 Man26AT는 glycosyl hydrolase family 26의 mannanase와 상동성이 높은 활성영역, 탄수화물 결합영역 CBM27과 CBM11로 구성되어 있었다. Man26AT의 아미노산 배열은 P. ihumii의 유추된 mannanase와 상동성이 81%이고 다른 Paenibacillus 속 균주의 여러 mannanases와 57% 이하의 상동성을 보였다. man26AT 유전자를 함유한 재조합 대장균의 균체 파쇄상등액은 $55^{\circ}C$와 pH 5.5에서 최대의 mannanase 활성을 보였고, $50^{\circ}C$에서 1시간 열처리한 후에 80% 이상의 잔존활성을 보였다. Man26AT는 locust bean gum (LBG) galactomannan과 konjac glucomannan에 대한 분해활성이 유사하였으며, carboxymethylcellulose, xylan과 para-nitrophenyl-${\beta}$-mannopyranoside는 분해하지 못하였다. Man26AT에 의해 mannotriose, mannotetraose, mannopentaose와 mannohexaose 등의 만노올리고당이나 LBG로부터 공통의 최종 가수분해 산물로 mannose, mannobiose와 mannotriose가 생성되었다. 또한 mannotriose 보다 큰 만노올리고당이 LBG와 guar gum의 분해산물로 각각 생성되었다. 그러나 Man26AT는 mannobiose를 분해하지는 못하였다. 활성염색을 통해 Man26AT는 균체 내에서 3개 이상의 크기가 다른 활성 단백질로 분해된 것이 확인되었다.

• 한국측량학회지
• /
• 제30권2호
• /
• pp.143-152
• /
• 2012

항공영상을 이용하여 수치표면자료와 같은 3차원 자료를 자동으로 제작하기 위해서는 영상정합이 반드시 필요하다. 최근 사용되고 있는 항공 디지털 프레임 영상은 과거의 아날로그 영상에 비해 폐색지역이 적은 고중복도 다중 스트립 영상으로 촬영되기에 용이하다. 최근 다중 스트립 영상을 이용한 다중영상정합 기법에 대한 연구가 많이 이루어지고 있으며, 특히 각 영상에서 추출된 점(point feature)이나 형상(linear feature)의 유사성 측정 방법에 대한 연구가 진행되고 있다. 본 연구에서는 수직궤적 기반 다중영상정합을 대상으로 영역기반 유사성 측정 방법으로 SNCC(Sum of Normalized Cross-Correlation)와 SSD(Sum of Squared-Difference) 방법을 비교 분석하였다. 또한 영역기반 유사성 측정에 필요한 요소로 영상의 화소값, 화소값 기울기 강도, 화소값과 화소값 기울기 강도 평균을 각각 사용하여 결과를 비교하였다. 이 외에도 영역기반 유사성 측정에서 중요한 요소인 기준 윈도우의 크기를 비정규 적응형 기준 윈도우 방법과 정규 적응형 윈도우 방법을 적용하여 결과를 비교 분석하였다. 실험을 위하여 사용된 항공영상은 ZI Imaging 사의 DMC (Digital Modular Camera)에 의해 종중복도는 80%, 횡중복도는 60%로 촬영되었으며, 3개의 스트립으로 구성되었다. 다양한 방법으로 실험을 수행한 결과에 따르면 유사성 측정 방법으로는 SNCC, 유사성 측정 요소로는 화소값과 화소값 기울기 강도 평균, 그리고 비정규 적응형 기준 윈도우가 수직궤적 기반 다중영상정합의 영역기반 유사성 측정에 가장 적합하다는 것을 확인하였다.