Insects possess two distinct acetylcholinesterases (AChE1 vs. AChE2), which are encoded by two paralogous loci originated from duplication. Kinetic analyses of several insect AChEs revealed that both AChE1 and AChE2 retain common catalytic properties of AChE but subtle kinetic differences also exist between these two AChEs. To understand how selection pressure has shaped the protein structure of AChEs and affected their function during evolution, we measured and compared the nucleotide diversity (Pi) and amino acid site-specific selection pressure between AChE1 and AChE2 from various insects. Highly conserved were the majority of the amino acid residues involved in forming the essential domains, including peripheral anionic site (PAS), and little differences were revealed between AChE1 and AChE2, suggesting the presence of strong purifying selection pressure over these essential residues. Interestingly, the EF-hand like motif was mostly found in the AChE1 lineage but not in AChE2. In addition, a unique amino acid difference in the PAS (D72 vs. Y72) was highly conserved between AChE1 and AChE2. Three-dimensional modeling of insect AChEs by particularly focusing on the PAS revealed that a subtle but consistent structural alteration in the active site topology was caused by the PAS amino acid substitution. Taken together, despite the long evolutionary history and low overall sequence similarity, both insect AChE1 and AChE2 still share a extremely high degree of structural and functional conservation, indicative of a strong purifying selection pressure. Nevertheless, only a small change in the PAS, appears to be associated with a local but significant alteration of AChE2 structure, which in turn drives the functional differentiation of AChE.

Silk fibroin (SF) and silk sericin (SS) have been studied as a biomaterial due their useful properties including good blood compatibility and good cell activities. However, previous studies, silkworm variety has not been considered although it can affect structure and properties of silk fibroin and sericin. Therefore, in the present study, structure and properties of silk fibroins and sericins obtained from different silkworm variety were examined. Most of regenerated SF solutions from different silkworm varieties displayed Newtonian fluid behaviors and their viscosities were different depending on the silkworm variety. N74 showed the highest viscosity among the SF samples. Molecular weight (MW) distribution and mechanical properties of regenerated SF showed similar result to viscosity result. SS did not show significant difference in MW distribution and viscosity result depending on the silkworm variety.

In this study, silk sericin solutions and films were prepared with different solvents: formic acid and water. Also, silk sericin film from aqueous solution was prepared at different casting temperature. Regardless of solvent type, silk sericin solutions showed a shear thinning implying highly molecular entangled state of silk sericin. Silk sericin aqueous solution showed a higher turbidity than that of formic acid solution. Silk sericin aqueous solution showed shorter gelation time than formic acid. FTIR results showed β-sheet crystallization of silk sericin was affected by casting solvent and temperature. Silk sericin film from aqueous solution showed more β-sheet conformation as the casting temperature was decreased. Silk sericin film from formic acid showed higher crystallinity index than silk sericin films cast from aqueous solution. XRD diffraction measurement showed similar results to those of FTIR. In case of mechanical properties, tensile strength of sericin film from formic acid was higher than sericin films from aqueous solution.

This study aims to evaluate structural safety through FEM on the hollow shaft and the shaft filled with aluminum foam as the impact beam made of high tensile strength steel, Force reactions of impact beams are investigated when the forced displacement of 50mm is applied equally on two beams. When impact velocity of 80km/h is applied onto impact beams equally with the limit velocity of automobile on national road, how much impact energies can be absorbed by beams are also investigated. As study result, impact beams without aluminum foam and with aluminum foam show the maximum reaction forces of 15.53kN and 20.34kN respectively in case of the forced displacement of 50mm. As impact analysis result, impact beams without aluminum foam and with aluminum foam can absorb impact energies of 560J and 820J respectively. As impact beam with aluminum foam has reaction force and impact energy more than 23% and 30% than without aluminum foam, impact beam with aluminum foam has more safety than without aluminum foam.

We examined various ball-milling parameters which affect the structural and morphological modification of multi-wall carbon nanotubes. In particular, the effect of milling mode and the use of different milling agents were exam- ined. Friction milling mode induced more structural changes than impact milling mode except the use of dry ice as a milling agent. Wet milling was helpful for reducing more effectively the agglomeration of nanotubes than dry milling. The use of hard solid particles such as silica and alumina as milling agents resulted in an effective shortening of nan- otubes, but often susceptible to the amorphization and the destruction of crystallinity.

본 연구에서는 구조용강 내 크랙의 성장특성을 크랙의 길이와 각도에 따라 규명하였다. 구조용강으로 만들어진 시편 내의 크랙에 위에 언급한 두 가지의 조건들을 적용하여 실험을 수행하였으며, 이를 통해 Strain energy와 변형량에 대해 알 수 있었다. 그리고 이들 Strain energy와 변형량을 바탕으로 응력확 대계수를 구하였으며, 구해진 실험값들의 검증을 위하여 유한요소 해석 프로그램을 사용하여 시뮬레이션 해석을 수행하였다.

본 연구는 알루미늄 폼 복합재료로 접합된 TDCB 모델에 대해 구조적 시뮬레이션 해석을 하였다. 이 해석을 통하여 등가응력, 변형 에너지 및 접착부의 압력에 대한 자료를 얻었다. 또한 실험을 하여 해석 자료에 대한 검증을 하였다. 본 연구의 자료를 통해 알루미늄 폼 재질로 접합된 실제 복합재 구조물에 적용시켜 파괴거동을 분석하고 그 기계적인 특성을 파악할 수 있다.

As fires have frequently occurred with large scale at cultural assets and warehouses, the development of Korean type demolition fire apparatus for efficient fire fighting becomes important. In this study, structural stability is investigated for assembly model of boom and outrigger by using computational structural analysis. Analysis results of boom and outrigger unit are also compared with assembly model. As this study result, equivalent stress result of boom unit is about 6% higher than assembly model and equivalent stress result of outrigger unit is about 15% higher than assembly model.

회전하는 수조에서 나타나는 순압성 소용돌이의 패턴과 구조 회전에 대한 연구를 수행하였다. 소용돌이는 수면 위에 접촉된 원판을 수조에 대해 상대적으로 회전시키는 방법을 통해 만들어졌다. 회전원판의 크기, 회전방향, 회전속력에 따라 트라이폴라 소용돌이, 삼각형 소용돌이, 사각형 소용돌이, 커다란 원형 소용돌이가 안정하게 나타났고, 모양이 계속 변하는 불안정한 소용돌이도 나타났다. 회전원판과 수조 벽 사이의 간격이 안정한 소용돌이의 패턴에 큰 영향을 주었고 불안정한 소용돌이는 원판이 시계방향으로 빠르게 회전할 때 주로 나타났는데, 그 원인은 원심력적 불안정성이었다. 한편, 트라이폴라 소용돌이에서 나타난 전체 패턴의 구조적 회전 각속도는 원판 가장자리의 선속도에 비례하였고, 고기압성 트라이폴라 소용돌이가 저기압성 보다 더 큰 구조 회전 각속도를 가졌다. 로스비 수와 구조회전의 관점에서 볼 때, 해양에서 발견된 트라이폴라 소용돌이와 본 실험에서 나타난 트라이폴라 소용돌이는 유사하였다.

This project is mainly related to evaluation of total energy consumption of low energy house, the exterior envelope of which was wholly composed of structural insulated panels(SIP). The U-value of applied SIP was in the range of 0.189 to 0.269W/㎡․K and the U-value of pair glass from 0.78 to 1.298W/㎡․K was applied for window dependent to its function respectively. For comparison of total energy performance, the energy simulation for pilot house was performed to compare with the control house having insulation criteria of Korean building regulation in 2009. Based on simulation of dynamic energy performance, the pilot house saved 48.3% of annual energy consumption while the control house in 2009 consumed as 85.7GJ/y. In case of heating, the result showed that the energy saving ratio amounted to 76.7%. For CO₂ emission, the pilot house diminished approximately 35.4% from 6,208.4kgCO₂ to 4,009.2kgCO₂. In payback period to early investment, it was analyzed the pilot house took 7.8 years, when the low energy house built by other insulation method with same thermal perfusion took 11.5 years. From this result, it is considered that the SIP is more effective, economic to Green Home application.

The demand for the structural system of reduction in story height increases because buildings are getting higher. The existing method of construction is not efficiency. Thus, it is hard to reduce the story height and this method cannot secure economics as expected. This study aims at developing the partially concrete-filled new type composite beam, which can efficiently resist against the negative moment and positive moment, for the reduction of deflection. Through case studies on loading of concentrated load and uniformly distributed load to fixed beam, we could find the most efficient ratio of moment of inertia. Consequently the gap space between middle and end beam can be used as facilities installation, moreover the suggested Omega beam system is expected to get the effect of reduction in story height as well as reduction of quantity.

휨 거동 및 전단부의 전단거동으로 인한 철근상세 및 사용되어지는 철근의 과다로 인하여 취성파괴의 양상이 발생 하고 있다. 이에 본 실험에서는 유리섬유망을 이용하여 철근과의 휨 및 변위 거동을 통하여 무보강철근과 유리섬유망의 ply 수에 따른 휨거동 실험을 통하여 균열을 살펴보고서 향후 휨 거동에 적정한 유리섬유망의 철근의 배치겹수에 대한 사용량을 검토하고자 한다.

본 연구는 과수재배 시설의 표준화 및 환경조절기술개발을 위한 기초자료로 제공하는 것을 목적으로 과수재배용 온실의 실태를 조사하여 구조유형과 설계요소를 분석하고, 기상재해에 대한 안전성과 구조 및 환경관리에 대한 개선방안을 검토하였다. 시설재배 면적이 가장 많은 5개 품목 중 주로 제주도에서 재배되고 있는 감귤과 현재 재배온실을 찾을 수 없는 단감을 제외한 포도, 배 및 복숭아재배 온실을 연구대상으로 하였다. 감귤과 포도재배 온실은 꾸준히 증가하고 있으나 저장시설의 발달로 배와 단감재배 온실은 감소하고 있는 추세이다. 앞으로는 비가림 효과가 크고 저장성이 떨어지는 품목을 중심으로 과수재배 온실의 변화가 예상된다. 조사대상 온실 중 배 재배 온실과 복숭아재배 대형 단동온실을 제외하고는 대체로 보급형 온실의 규격을 따르고 있으며, 재배작목별로 특성화된 온실은 없는 것으로 나타났다. 과수재배 온실의 대부분은 농촌진흥청과 농림수산식품부에서 고시한 농가보급형 모델이나 내재해형 모델의 부재규격을 따르고 있었다. 기초는 대부분 콘크리트 기초를 사용하고 있었으며, 배 재배 온실의 경우에는 내재해형 모델보다 두꺼운 단면의 기둥을 사용하고, 강판을 기둥의 하단에 용접하여 매설한 형태의 특수한 기초를 적용하고 있었다. 조사대상 온실의 구조적 안전성을 검토한 결과 대부분 안전하였으나 김천과 천안의 포도재배 온실, 남원과 천안의 복숭아재배 온실에서 적설에 불안전한 것으로 나타났고, 남원의 복숭아재배 온실은 풍속에 대한 안전성도 부족한 것으로 나타났다. 또한 채소재배 온실을 복숭아재배로 전용한 온실의 경우 적설과 풍하중 모두 상당히 불안정한 것으로 나타났다. 과수의 수형, 수고 및 재식간격을 고려하여 과수 재배 온실의 적정규격을 검토한 결과 포도재배 온실은 폭 7.0~8.0m, 측고 2.5~2.8m가 적당하고, 배와 복숭아재배 온실은 폭 6.0~7.0m, 측고 3.0~3.3m 정도가 적당한 것으로 판단된다.

Structural insulated panels, structurally performed panels consisting of a plastic insulation bonded between two structural panel facings, are one of emerging products with a viewpoint of its energy and construction efficiencies. These components are applicable to fabricated wood structures. In Korea, there are few technical documents regulated structural performance and engineering criteria in domestic market. This study was conducted to identify fundamental performance of both monotonic load and quasi static cyclic load for SIPs in shear wall application. Static test results showed that maximum load was 44.3kN, allowable shear load was 6.1kN/m, shear stiffness was 1.23 M N/m, and ductility ratio was 3.6. Cyclic test was conducted by two kinds of specimens : single panel and double panels. Cyclic test results, which were equivalent to static test results, showed that maximum load was 45.42kN, allowable shear load was 6.3kN/m. Furthermore the accumulated energy dissipation capability for double panels was as 2.3 times as that for single panel. From performance of structural tests, it was recommended that the allowable shear load for panels was at least 6.1kN/m.

This study aims to analyze the structural behavior on TDCB models bonded adhesively with aluminum foam composite. These simulation models are designed on the basis of British industrial and ISO standards. The variable of configuration factor(m) is set up to investigate the fracture toughness of bonded joint due to the volume of material. Equivalent stress, deformation energy, pressure at bonded part, reaction force-crack length, energy release rate-crack length are obtained by this analysis. Through the data of this study, the fracture behavior can be analyzed by applying the practical composite structure bonded with aluminum foam and the mechanical property can be understood.

부유구조물은 해양에서 다양한 외력을 경험하게 되며 특히, 파랑하중은 구조물의 설계에 결정적인 지배인자로 간주되고 있다. 이런 구조물은 파장과 크기의 상대적 관계로 소형구조물, 대형구조물 등으로 구분될 수 있으며 전통적으로 소형구조물은 회절발생이 없는 것으로 가정하며 대형구조물은 회절 작용에 따른 관성력만을 고려하여 파랑하중을 산출한다. 따라서 이 연구에서는 해양과 강, 호수 등에서 주로 사용되고 있는 정사각형 부유구조물을 이용하여 동유체력과 구조응답의 상관관계를 파악하여 장방형 부유구조물의 안전성에 대한 영향을 검토하였다.

The concrete-filled tube (CFT) column has the excellent structural performance. But it is difficult to connect with column and beam because of closed section. Its Solution, 2 members of ㄷchennel in which Internal diaphragm is installed were welded beforehand and the method of making Rectangular Steel Tube was proposed. According to upside and downside junction shape, Internal diaphragm suggested as symmetric specimen and asymmetric specimen. The upper and lower diaphragm of the Symmetric specimen used the same horizontal and The upper diaphragm of the Asymmetric specimen used the horizontal plate and the lower diaphragm used the vertically plate. In this research, 4 T-shape column to beam steps connections were tested with cyclic loading experiment in order to evaluate the structural capability of the offered connection. Symmetric specimens be a failure in 0.03rad from beam flange. And Asymmetric specimens be a failure in 0.05rad from column interface. The comparison results of All specimens shown similar to energy absorption capacity in 0.02rad.