곤충병원성 선충은 해충 방제를 위해 세계적으로 많은 연구가 이루어지고 있으 며, 최근 국내에서 곤충병원성 선충을 이용한 농림해충 방제에 활용되고 있다. 본 연구는 이러한 곤충병원성 선충 중에서 주로 십자화과 작물을 가해하는 나비목 해 충의 방제에 이용되고 있는 Steinernema carpocapsae의 살포 횟수에 따른 토양의 환경조건에 적응하는 개체의 생존기간과 나비목 해충에 대한 병원력을 검정하여 보았다. 야외 토양조건을 고려하여 온도를 20 ~ 30℃까지 다양하게 처리하였으며 50% 이상의 습도를 유지하여 4주간 조사하였다. 토양은 야외에서 채집하여 적당 량의 유기물과 혼합하여 멸균하였고, 20 units/103 cm의 선충을 3일 간격으로 최대 3회까지 살포하였다. 그 결과 2회 이하 살포하였을 경우 30%이하의 낮은 생존률을 나타내었고, 3회 살포하였을 경우 50% 이상의 높은 생존률을 나타내었다. 살충력 은 2회 이하 살포하였을 경우 약 2주간 높은 살충력이 지속되었으며, 3회 방제하였 을 경우 4주까지 높은 병원력이 유지되었다. 또한 4주간 병원력이 유지된 처리구의 토양과 저온에서 보관중인 선충 그리고 Bt 생물농약을 배추좀나방과 담배거세미 나방에 대해 처리하였을 때 모든 처리구의 살충률이 80% 이상의 살충률을 나타내 었다. 이러한 결과는 곤충병원성 선충을 이용한 나비목 해충의 지속가능한 방제의 가능성을 제시하고 있다

 ,  , Effect of a new crop protectant ‘Bt-Plus’ on natural enemies was analyzed in this study. Tested natural enemies included two parasitic species of Aphidius colemani and Eretmocerus eremicus, and four predatory species of Harmonia axyridis, Orius laevigatus, Amblyseius swirskii, and Phytoseiulus persimilis. ‘Bt-Plus’ was formulated by combination of three entomopathogenic bacteria (Xenorhabdus nematophila (Xn), Photorhabdus temperata subsp. temperata (Ptt), Bacillus thuringiensis (Bt)) and bacterial metabolite (BM). All three types of ‘Bt-Plus’ showed significantly higher toxicities against fourth instar Plutella xylostella larvae than Bt single treatment. Two types of bacterial mixtures (‘Xn+Bt’ and ‘Ptt+Bt’) showed little toxicity to all natural enemies in both contact and oral feeding assays. However, ‘BM+Bt’ showed significant toxicities especially to two predatory mites of A. swirskii and P. persimilis. The acaricidal effects of different bacterial metabolites were evaluated against two spotted spider mite, Tetranychus urticae. All six BM chemicals showed significant acaricidal effects. The BM mixture used to prepare ‘Bt-Plus’ showed a high acaricidal activity with a median lethal concentration at 218.7 ppm (95% confidence interval: 163.2 - 262.3). These toxic effects of bacterial metabolites were also proved by cytotoxicity test against Sf9 cells. Especially, benzylideneacetone, which was used as a main ingredient of ‘BM+Bt’, showed high cytotoxicity at its low micromolar concentration.

 ,  , The entomopathogenic bacterium, Xenorhabdus sp., was isolated from an entomopathogenic nematode, Steinernema monticolum. When these bacteria were injected into the hemocoel of the diamondback moth, Plutella xylostella, they caused significant mortality. However, the bacterium was not pathogenic when it was administered orally. This study showed that Xenorhabdus sp. significantly enhanced oral pathogenicity of Bacillus thuringiensis (Bt) against the last instar larvae of P. xylostella. Different ratios of culture broth of Xenorhabdus sp. and Bt showed significantly different pathogenicities against P. xylostella. In field tests, the optimal bacterial mixture significantly enhanced control efficacy against P.xylostella compared to Bt treatment alone. These results demonstrated that Xenorhabdus sp. culture broth can be developed as a potent biopesticide by enhancing the insecticidal efficacy of Bt.

Bacillus thuringiensis (Bt) is a bacterial biopesticide against insect pests, mainly lepidopterans. Spodoptera exigua and Plutella xylostella exhibit significant decreases in Bt susceptibility in late larval instars. To enhance Bt pathogenicity, we used a mixture treatment of Bt and other bacterial metabolites which possessed significant immunosuppressive activities. Mixtures of Bt with culture broths of Xenorhabdus nematophila (Xn) or Photorhabdus temperata ssp. temperata (Ptt) significantly enhanced the Bt pathogenicity against late larval instars. Different ratios of Bt to bacterial culture broth had significant pathogenicities against last instar P. xylostella and S. exigua. Five compounds identified from the bacterial culture broth also enhanced Bt pathogenicity. After determining the optimal ratios, the mixture was applied to cabbage infested by late ins tar P. xylostella or S. exigua in greenhouse conditions. A mixture of Bt and Xn culture broth killed 100% of both insect pests when it was sprayed twice, while Bt alone killed less than 80% or 60% of P. xylostella and S. exigua, respectively. Other Bt mixtures, including Ptt culture broth or bacterial metabolites, also significantly increased pathogenicity in the semi-field assays. These results demonstrated that the Bt mixtures collectively names 'Bt-Plus' can be developed into potent biopesticides to increase the efficacy of Bt.

Benzylideneacetone (BZA) is a compound derived from culture broth of an entomopathogenic bacterium, Xenorhabdus nematophila (Xn). Its immunosuppressive activity is caused by its inhibitory activity against eicosanoid biosynthesis. This BZA is being developed as an additive to enhancc control efficacy of other commercial microbial insecticides. This study was focused on the enhancement of the immunosuppressive activity of BZA by generating its chemical derivatives toward decrease of its hydrophobicity. Two hydroxylated BZA and one sugar-conjugated BZA were chemically synthesized. All derivatives had the inhibitory activities of BZA against phospholipase A<SUB>2</SUB> (PLA<SUB>2</SUB>) and phenoloxidase (PO) of the diamondback moth, Plutella xylostella, but BZA was the most potent. Mixtures of any BZA derivative with Bacillus thuringiensis (Bt) significantly increased pathogenicity of Bt. BZA also inhibited colony growth of four plant pathogenic fungi. However, BZA derivatives (especially the sugar-conjugated BZA) lost the antifungal activity. These results indicated that BZA and its derivatives inhibited catalytic activities of two immune-associated enzymes (PLA2 and PO) of P. xylostella and enhanced Bt pathogenicity. We suggest its use to control plant pathogenic fungi.

A remote sensing pheromone trap called IT pheromone trap (Korean patent: 10-0982563) was applied to monitor overwintering population changes of the oriental fruit moth, Grapholita molesta, for three successive years in apple orchards. Males of the overwintering populations were attracted during April and May. However, the occurrence peak was delayed and extended to early June in 2010, at which the average spring temperature was significantly lower than the previous years. These overwintering populations could be monitored by the remote-sensing pheromone trap. When the remote-sensing pheromone traps were deployed to apple orchards of different provinces in Korea in 2010, the maximal overwintering populations of G. molesta were monitored at May in all areas. However, the population sizes monitored were significantly different among different localities. This study suggests a practical application of IT pheromone trap to monitor G. molesta in field conditions.

An entomopathogenic bacterium, Photorhabdus temperata ssp. temperata (Ptt), suppresses insect immune responses and facilitates its symbiotic nematode development in target insects. The immunosuppressive activity of Ptt enhances pathogenicity of various microbial pesticides including Bacillus thuringiensis (Bt). This study was performed to select a cheap and efficient bacterial culture medium for large scale culturing of the bacteria. Relatively cheap industrial bacterial culture media (MY and M2) were compared to two research media, Luria-Bertani (LB) and tryptic soy broth (TSB). In all tested media, a constant initial population of Ptt multiplied and reached a stationary phase at 48 h. However, more bacterial colony densities were detected in LB and TSB at the stationary phase compared to two industrial media. All bacterial culture broth gave significant synergism to Bt pathogenicity against third instars of the diamondback moth, Plutella xylostella. Production of bacterial metabolites extracted by either hexane or ethyl acetate did not show any significant difference in total mass among four culture media. Reverse phase HPLC separated the four bacterial metabolites, which were not much different in quantities among four bacterial culture broths. This study suggests that two industrial bacterial culture media can be used to economically culture Ptt in a large scale.

A bacterial colony was isolated from the gut of the bean bug, Riptortus clavatus. From morphological and biochemical tests, the bacterial isolate showed the highest similarity to Staphylococcus succinus. DNA sequence of 16S rRNA gene of the bacterium supported the identification. Oral administration of penicillin G to adults of R. clavatus gave a dose-dependent mortality of adults of R. clavatus to adults along with significant decrease of the bacterial population in the gut. Similarly, three metabolites (benzylideneacetone, proline-tyrosine, and acetylated phenylalanine-glycine-valine) derived from an entomopathogenic bacterium, Xenorhabdus nematophila, also inhibited growth of the gut bacterial population and gave significant mortalities to R. clavatus. These results suggest that a gut bacterial population classified as Staphylococcus sp. is required for survival of R. clavatus and that the three bacterial metabolites had toxic effects on the bugs due to their antibacterial properties.

Two groups of entomopathogenic bacteria, Xenorhabdus and Photorhabdus, are known to suppress insect immune responses by inhibiting eicosanoid biosynthesis. This study used these bacterial culture broths to develop novel biochemical insecticides against the diamondback moth, Plutella xylostella. Though the bacterial culture broths alone showed little insecticidal activity, they significantly enhanced pathogenicity of Bacillus thuringiensis against the fourth instar larvae of P. xylostella. Sterilization of the bacterial culture broth by autoclaving or 0.2 ㎛ membrane filtering did not influence the synergistic effect on the pathogenicity of B. thuringiensis. Three metablites identified in the culture broth of X. nematophila also showed similar synergistic effects. In field test, both entomopathogenic bacterial culture broth also enhanced the control efficacy of B. thuringiensis against P. xylostella.

건축용 막재는 일반적으로 직포와 코팅으로 구성되며, PTFE 계열 막재는 유리섬유로 만들어진 직포에 테프론 코팅으로 구성된다. 일반적으로 PTFE 막재에 사용되는 직포에는 β-yarn이 주로 사용되며, β-yarn이 아닌 α-yarn이 사용된 막재도 점차적으로 사용되는 시점이다. 그러나 α-yarn으로 직조된 직포로 만들어진 건축용 막재의 특성에 관한 정보는 일반 막재에 비해 많이 부족한 편이다. 따라서 건축용 막재를 구성하는 직포를 만드는 원사의 굵기에 따른 막재의 역학적 특성에 대한 연구가 필요하다. 본 연구에서는 실험을 통하여 원사가 서로 다른 막재의 인장 특성을 비교 분석하고자 한다.

Mating disruption (MD) using synthetic sex pheromone lures has been used to control the Oriental fruit moth, Grapholita molesta (Busck), in apple orchards. In Korea, where several small apple orchards are clustered but independently managed, its efficacy has been suspected mainly due to immigration of any mated females from nearby untreated cultivating areas. This study developed an edge treatment technique to decrease any local MD-free zones in a specific MD-treated farm and to trap any immigrating mated females by installing MD lures and food traps around the apple farm with 10 meter intervals. The addition of the edge treatment to the MD significantly prevented leaf and fruit damages induced by G. molesta compared to MD only. Moreover, this study tried to optimize the MD control technique by determining frequency of MD application. It suggests two MD applications with the edge treatment at the end of March and at the early of July to be effective throughout the entire apple growing seasons.

Two entomopathogenic bacteria, Xenorhabdus nematophila and Photorhabdus temperata subsp. temperata, are known to be potent against the diamondback moth, Plutella xylostella, when the bacteria are injected into the hemocoel. This study investigated any pathogenic effect of their culture broth on P. xylostella by oral administration. Only culture broth of both bacterial species did not give enough pathogenic effects by the oral administration. However, when the culture broth was orally treated together with Bacillus thuringiensis (Bt), both cell-free culture broth significantly enhanced Bt pathogenicity against the 3rd instar larvae of P. xylostella. The culture broth was then fractionated into hexane, ethyl acetate, and aqueous extracts. Most synergistic effect on Bt pathogenicity was found in ethyl acetate extracts of both bacterial species. Thin layer chromatography of these extracts clearly showed that ethyl acetate extracts of both bacterial culture broths possessed metabolites that were different to those of hexane and aqueous extracts. These results suggest that the both entomopathogenic bacteria produce and secrete different factors to give significant synergistic effect on Bt pathogenicity.

대공간 구조물은 힘의 흐름을 자연스럽게 하고, 휨모멘트의 영향을 가능한 저감 시켜 면내력만으로 외부하중에 저항하는 역학 개념을 기초로, 구조 시스템의 효율성을 극대화시키는 형태저항형 구조이다. 구조물의 경제성 분석은 그 프로젝트의 실행을 결정할 수 있는 중요한 요소이다. 대공간 건설에는 일반 건물에 비해 많은 기술적 고려가 요구된다. 프로젝트의 성공적인 수행을 위해 타당성 검토 단계에서 구조물의 전 생애의 필수적인 요소에 대한 분석이 요구된다. 본 논문에서는 기존 대공간 구조물의 사례를 조사하며, 이를 통해 자료를 수집하고 공사비를 분석하였다. 본 연구는 대공간 구조의 데이터 베이스 구축을 위한 기본적인 데이터 제공을 목적으로 한다.

구조물의 경제성 분석은 그 프로젝트의 실행을 결정할 수 있는 중요한 요소이다. 본 논문에서는 기존에 건설된 철골 트러스 스타디움 구조물의 건설비용 분석을 통하여 대공간구조물의 공사비 비용구조를 분석하였다.

구조물의 경제성 분석은 그 프로젝트의 실행을 결정할 수 있는 중요한 요소이다. 본 논문에서는 대공간구조물의 경제성 분석을 위하여 기존에 건설된 대공간 구조물(제주 월드컵 경기장)의 건설비용을 분석하여 경제성 분석 모델의 구축을 위한 기초 자료를 제공하고자 하였다.

The Space structures may have large freedom in scale and form. And especially Hybrid structures are received much attention from the view points of their light weight and aesthetics. Hybrid systems are stable structures which are reticulated spatial structures composed of compressive straight members, struts and cables and Membranes. In this paper, The Hybrid Unit System are suggested using the Membrane and Cable elements based on the Tensegrity Unit system. Also, The Hybrid System of double-layered single curvature is presented. We analyze the force density method allowing form-finding for Tensegrity systems. And We analyze the shape analysis by the LARSH which is the program for nonlinear analysis.

In this work, a finite element model is presented for geometrically non-linear analysis of shell structures. Finite element by using a three-node flat triangular shell element is formulated. The non-linear incremental equilibrium equations are formulated by using an updated Lagrangian formulation and the solutions are obtained with the incremental/iterative Newton-Raphson method and arc length method. Some of results are presented for shell structures. The obtained results are in good agreement with the results available in existing literature.

Tensegrity systems are stable structures which are reticulated spatial structures composed of compressive straight members, struts and cables. But there are some difficulties concerning surface stability, surface formation and construction method. One of the ways to solve this problem reasonably is combination of tesile members and rigid members. This structure is a type of flexible strutural system which is unstable initially because the cable material has little initial rigidity. Therefore tensegrity structure need to be introduced to the Initial stress for the self-equilibrated system having stable state. The rigidification of tensegrity systems is related to selfstress states which can be achieved only when geometrical and mechanical requirements are simultaneously satisfied. In this paper, for the stabilization of tesnsegrity structure it is proposed the modified self-equilibrated equation and the range of the various geometrical parameter about unit system. And we generate the model of double layed single curvature arch using the new squew quadruplex unit system.

In this study, the 'force density method' for shape finding of cable net structures is presented. This concept is based on the force-length ratios or force densities which are defined for each branch of the net structures. This method renders a simple linear 'analytical form finding' possible. If the free choice of the force densities is restricted by further condition, the linear method is extended to a nonlinear one. The nonlinear one can be applied to the detailed computation of networks. In this paper, the general inverse matrix is introduced to solve the nonlinear equilibrium equation including Jacobian matrix which is rectangular matrix. Several examples for linear and nonlinear analysis applied additional constraints are presented. It is shown that the force density method is suitable for form finding of cable net and the general inverse matrix can be applied to solve the nonlinear equation without Lagrangian factors.

본 논문의 목적은 막구조물의 형상해석, 응력-변형 해석, 재단도 해석을 수행하는 것이고, 재료는 선형탄성, 응력은 평면응력의 상태로 가정한다. 케이블 및 막구조물은 외력에 대한 변형이 매우 큰 구조물이기 때문에 기하비선형을 고려한 비선형해석을 하여야 한다 해석은 일반적인 구조물과는 달리 다음의 3단계로 구성된다. 첫 번째 단계는 초기 평형형상을 결정하기 위한 형상해석이고, 두 번째 단계는 다양한 외력이 가해졌을 때 구조물의 거동을 파악하는 응력-변형 해석이다. 이렇게 하여 일단 만족된 형상이 얻어지면 형상해석에서 얻은 결과를 기초로 하여 시공적 관점의 재단도 해석이 수행된다. 본 논문에서는 서귀포 월드컵 축구 경기장 지붕 구조물의 예를 들어 형상해석, 응력-변형 해석, 재단도 해석을 수행하고, 카테노이드(Catenoid) 구조물을 이용하여 최적재단도에 관한 해석기법을 제시한다.