노지 나방류 해충인 담배거세미나방 방제를 위한 유충기생성 천적 2종인 긴등기생파리와 예쁜가는배고치벌 의 방사조건을 확립하고자 콩 재배포장에서 방사거리 및 방사밀도별 기생율을 조사하였다. 긴등기생파리는 방사 후 24시간 이내 방사지점으로부터 10m까지 이동하여 나방류 유충을 기생하였으며, 예쁜가는배고치벌도 방사지점으로부터 15m에서도 기주유충에 산란하여 고치가 형성된 것이 확인되었다. 긴등기생파리는 면적당 방사밀도가 높아질수록 기생율이 증가했으며, ㎡당 0.15마리(천적:해충=1:5) 방사했을 때 평균기생율 63.1%로 나타났다. 예쁜가는배고치벌은 긴등기생파리와 같은 방사밀도에서 평균기생율 47.8%로 확인되었으나, 방사 밀도에 따른 기생율 차이는 없었다.

The density of molten salts is the most important property in the development of molten salt reactor (MSR). The density value measured through the experiment is also very valuable as a gold standard for the validation of the prediction models based on molecular dynamics or other computational methods. To the best of our knowledge, the experimental density data of the ternary NaCl-MgCl2- UCl3 salt system as a MSR candidate fuel salt have never been reported previously. In this study, density measurement experiment of high-temperature molten salt of NaCl-MgCl2 and NaCl-MgCl2- UCl3 was conducted using a previously-developed density measurement system based on the maximum bubble pressure (MPB) method. As a result of the experiment, the density value of 62NaCl- 18MgCl2-20UCl3 molten salt at 873 K was 2.62 g/cm3. A density prediction value of 2.65 g/cm3 at 873 K was derived from the obtained results based on the rule of additivity of molar volume method. The predictred density of 62NaCl-18MgCl2-20UCl3 was consistent with the experimental value within 1%. The density measuring system used in this study is promising for the validation of other multicomponent molten salt systems.

본 연구는 상업 젠트리피케이션의 과정을 일반과 프랜차이즈 커피전문점의 시·공간 밀도 변화를 이용하여 탐색하고자 한다. 커피전문점은 높은 입지 가변성으로 상권의 형성과 발달을 파악하기에 효과적 업종이기 때문에 상업 젠트리피케이션의 진행 단계를 직관적으로 설명하는 효과적인 지표의 역할을 할 수 있다. 본 연구에서는 먼저, 상업 젠트리피케이션을 경험한 사례 지역을 분석하여 커피전문점 밀도를 이용한 상업 젠트리피케이션 진행 단계 탐색의 가능성을 보여주었다. 다음으로 커피전문점의 상대 밀도와 밀도 비율을 추정하고 그 변화량을 기반으로 군집분석 방법을 적용하여 서울 전 지역을 대상으로 상업 젠트리피케이션 진행 단계를 구분하였다. 그 결과 상업 젠트리피케이션이 진행되었거나 진행 중인 지역과 기간을 효과적으로 추정 할 수 있었다. 더불어 커피전문점의 밀도를 이용한 상업 젠트리피케이션의 탐색은 인구·사회·경제적 변수들보다 더욱 상세한 시·공간 변화 탐색에 효과적이다.

We investigated densities of the bean bug, R. pedestris (Alydidae) and three Pentatomidae stinkbug species, Dolycoris baccarum, Nezera antennata and Halyomorpha halys in an experimental field in Suwon, 2018. Three pheromone traps for R. pedestris adults were installed at distances of more than 50 meters from soybean fields. The adults began to be caught from late March. Its mean number increased from early August, and reached a maximum at early September. The fluctuation aspects of adult number caught, however, were different among trapping sites. Soybean and mungbean were sowed at June 21, and all stages of stinkbugs were scouted from July 18 to late September through direct observation. Adults and eggs of R. pedestris were not observed during the vegetative stage of soybean, but observed first at the flowering stage, mainly early August, of reproductive stage. The results indicated that R. pedestris adults invaded into soybean fields at the flowering stage, despite of inhabitation in the surrounding area during the pre-reproductive stage of soybean. Adults of only D. baccarum in Pentatomid stinkbugs were found at the vegetative stage of soybean. Densities of R. pedestris were compared between two mungbean cultivars, which those seeds have been known to be resistant and susceptible to feeding of the bean bug, respectively. The densities of the third and fifth instar nymphs were higher on the susceptible cultivar than on the resistant cultivar, but densities of egg, adult, and the first and second instar nymphs were not significantly different between the two cultivars.

노린재류는 복숭아, 매실, 자두, 살구 등 핵과류 과실을 가해하는 해충으로 알려져 있다. 그러나 아직 핵과류 과원에서 과실을 가해하는 노린재 종에 대한 자세한 정보가 없어 효과적인 방제대책을 수립하기 어려운 실정이다. 우리는 2017년과 2018년에 핵과류 과실을 가해하는 노린재의 종류와 발생 밀도를 다양한 계절에 여러 지역에서 육안으로 조사하였다. 핵과류 6종(매실, 자두, 복숭아, 양앵두, 플럼코트, 살구)을 가해하는 노린재류는 총 4종으로써 썩덩나무노린재, 갈색날개노린재, 가시노린재, 알락수염노린재였다. 매실, 복숭아, 양앵두, 살구를 가해하는 우점 노린재는 썩덩나무노린재였던 반면, 자두에서는 갈색노린재의 밀도가 가장 높았다. 핵과류를 가해하는 노린재 중에서 썩덩나무노린재가 차지하는 비율은 64.2%였고, 갈색날개노린재는 23.7%를 차지하여 이 2종이 약 88%를 점유하였다. 따라서 핵과류에서 피해가 가장 큰 썩덩나무노린재의 체계적인 관리방안에 대한 연구가 필요하다.

The objective of this study was to investigate the growth rate and the optimal stocking density of sea cucumbers. Grow-out was studied in situ by conducting a follow-up survey using visible implant elastomer (VIE) tags. The rearing systems were made of polypropylene pipe for the frames and netting. The experiment ran for 70 days near Yeosu, Korea in the water depth of about 7 m. A total of 576 sea cucumbers which have three groups of body sizes (small: 5.15, medium: 12.34 and large: 23.26 g) were used. The five groups of stocking densities (150, 300, 450, 600 and 850 g/m2) in rearing system for sea cucumber were considered. Sea cucumbers were fed a mixed diet (mud, mineral, fish meal, etc.). The feed was supplied to 10% of their body wet weight once every 7 days. The survival rate (73%) of sea cucumber in 850 g/m2 was lower than those of other density groups (150 g/m2: 89%, 300 g/m2: 84%, 450 g/m2: 78% and 600 g/m2: 86%). The survival rate of medium size group was higher than those of small and large groups regardless of the density (P<0.05). Most of density groups have no significant difference except for 850 g/m2 (P>0.05). The growth rate of small size group (0.63% day-1) was higher than those of medium (0.38% day-1) and large (0.34% day-1) group regardless of the density (P<0.05). The threshold water temperature was 11.0°C for sea cucumber growth in winter season.

본 연구는 딸기의 2단 고설베드재배가 끝난 여름철 동안 수박재배 시, 베드 위치와 재식밀도가 수박의 과실 품질에 미치는 영향을 구명하고자 하였다. 고설 베드상자는 길이 102cm, 폭 22cm, 높이 13cm의 규격이고, 배지는 코코피트(coir)를 사용하였다. 수박은 베드 위치 및 재식밀도에 따라 베드상단 1주(A), 베드 상하단 각 1주로 상단(B) 및 하단(C), 상하단 각2주로 상단 2주(D), 하단 2주(E)로 정식 처리하였다. 수박은 2012년 5월 8일에 2단 고설베드에 정식하여 양액과 점적관수로 재배하였고 7월 25일에 수확되었다. 수박의 품질을 비교하고자, 과실 무게와 크기를 조사하였고, 과육 내 비타민 C, 플라보노이드, 페놀화합물, 당도 및 산도 등의 기능성 화합물을 분석하였다. 과실의 외관 품질인 과고, 과폭 및 과중은 A처리가 다른 처리에 비하여 가장 높았다. 특히 과중은 A, B, C, D, E처리 순으로 무거웠다. 식물체의 초장이나 엽수는 유의적 차이가 없었으나 줄기 직경과 엽면적은 A처리가 유의하게 컸다. 수박 과육 내플라보노이드, 항산화 활성 및 산도는 처리 간에 유의적 차이가 없었다. 한편 당도는 A, B 및 D 처리에서 유의하게 높게 나타났다. 또한 페놀화합물 함량은 A처리가 가장 높았다. 이상의 결과로 보아 대과의 수박 생산을 위해서는 A처리, 소과의 수박 생산에는 D와 E의 처리가 유리할 것으로 판단되었다.

Distribution of aquatic organisms is governed by various environmental factors Hydromorphological characteristics which are heavily affected by heavy rains in stream are one of the fundamental factors to influence the distribution of aquatic organisms. In this study we evaluated the difference response of two aquatic species Chironomus yoshimatisui and Limnodrilus hoffmesteri habiting to changes of discharge due to heavy rains. We compared the differences in their resilience and recover to disturbances. Our results showed that after a heavy rain during the sampling periods, the proportion of macrosubstrate highly increased and was not recovered into the previous states. Nonmetric Multi-dimensional scaling based on Chironomidae and Oligochaeta biota well represented annual and seasonal differences with heavy rain effects. Random forest model showed that the abundance of C. yoshimatisui were mainly influenced by microsubstrate, precipitation and Reynolds number, whereas stream roughness, mesosubstrate and macrosubstrate much more influenced the abundance of L. hoffmesteri.

In some cicada species, male calling songs are so loud that they become a nuisance to city dwellers in Korea. To understand the abundance of cicada species in central Korea, we conducted complete enumeration surveys of exuviae in Hyalessa fuscata, Cryptotympana atrata, Meimuna spp, and Graptopsaltria nigrofuscata. Exuviae collection was conducted in three representative habitats in central Korea: metropolitan, suburban, and country. We collected the exuviae twice with a 10-day interval between samplings in August 2010. Resource-weighted density of each species was calculated based on the area and the number of trees. H. fuscata was the dominant species in all three regions. Resource-weighted densities in metropolitan and suburban regions were much higher than those in the country region, due to H. fuscata and C. atrata. The results of the multivariate general linear models showed that region, date, and the interaction between these two variables were all significant for population densities of cicada species. Unlike the resource-weighted densities, the organism-weighted densities that indicated the intensity that an individual had to share its host with others were much larger than tree-weighted densities for cicada exuviae. Furthermore, there was no significant difference in organism-weighted densities among habitats. The difference between resource-weighted and organism-weighted densities implied that larger proportions of trees were not used by cicada juveniles in the country. Thus, the distributions and abundance of tree host species could be an important factor for cicada density in Korea.

Sweetpotato whitefly, Bemisia tabaci, is a vector of more than 100 plant-diseased viruses, as well as a serious pest of various horticultural plants. This species harbors a primary endosymbiont Portiera along with several secondary endosymbionts such as Cardinium and Hamiltonella. We investigated whether or not TYLCV acquisition alters the densities of endosymbionts in the body of B. tabaci using quantitative real-time PCR. Our results showed that the densities of both Cardinium and Hamiltonella, but not Portiera, increased upon acquisition of TYLCV. In addition, expression of GroEL, a molecular chaperone produced by Hamiltonella, was significantly upregulated in TYLCV-infected whiteflies. Our results suggest that endosymbionts may play an important role in TYLCV transmission mechanism within the body of B. tabaci.

The properties of SOFC unit cells manufactured using the decalcomania method were investigated. SOFC unit cell manufacturing using the decalcomania method is a very simple process. In order to minimize the ohmic loss of flattened tube type anode supports of solid oxide fuel cells(SOFC), the cells were fabricated by producing an anode function layer, YSZ electrolyte, LSM electrode, etc., on the supports and laminating them. The influence of these materials on the power output characteristics was studied when laminating the components and laminating the anode function layer between the anode and the electrolyte to improve the output characteristics. Regarding the performance of the SOFC unit cell, the output was 246 mW/cm2 at a temperature of 800˚C in the case of not laminating the anode function layer; however, this value was improved by a factor of two to 574 mW/cm2 due to the decrease of the ohmic resistance and polarization resistance of the cell in the case of laminating the anode function layer. The outputs appeared to be as high as 574 and 246 mW/cm2 at a temperature of 800˚C in the case of using decalcomania paper when laminating the electrolyte layer using the in dip-coating method; however, the reason for this is that interfacial adhesion was improved due to the dense structure, which leads to a thin thickness of the electrolyte layer.

To evaluate the influence of Meloidogyne incognita on hot pepper, hot pepper seedlings (Capsicum annuum cv. Supertankang) were planted in wooden box microplot (30×40×15cm, L×W×H) and growth and fruit yield were measured in a greenhouse condition from June to Nov., 2010. The initial population densities(Pi) of root knot nematode in the microplots were adjusted to 0, 10, 30, 100 and 300 second-stage juveniles (J2) in 100cm3 of soils. The fruit yields were inversely correlated with Pi and the relationship of total fruit yield to Pi could be adequately described by a linear regression equation, Y=0.18-0.039×LOG10(Pi+1), R2=0.49**. The Pi of 30 J2/100cm3 root knot nematode before planting caused yield loss exceed the economic threshold of non-fumigant nematicide application compared. Non-fumigant nematicides for M. incognita should be applied level around 30 J2/100cm3 soil for proper cultivation.

The sweetpotato whitefly, Bemisia tabaci, acts as a vector of more than 100 plant viruses. B. tabaci is known to harbor a primary endosymbiont (Portiera) and 6 secondary endosymbionts (Arsenophonus, Cardinium, Fritschea, Hamiltonella, Rickettsia and Wolbachia). These endosymbionts play important roles in the acquisition and transmission of plant viruses. Using PCR analysis, we identified endosymbiotic bacteria in various B. tabaci populations collected from different places of Korea. Distribution of endosymbionts was different according to the biotype of B. tabaci. Subsequently, their relative densities of endosymbionts were compared between TYLCV-viruliferous and non-viruliferous populations of the Q biotype using quantitative realtime PCR. We found that the densities of Portiera, Cardinium and Hamiltonella are higher in viruliferous than non-viruliferous whiteflies. Our results suggest the role of endosymbiont for the TYLCV transmission of whiteflies.

Insect pest may move to near area to forage the food by adverse changes of their environments. Understanding these behaviors of searching the host will be helpful for further control. This study was performed to investigate the host preference and distribution of B. tabaci in a host plant when they needs. Once entered an area including hosts, B. tabaci will select a host rather than non-host and stayed for living. Dispersal within a niche (in a whole plant), B. tabaci was observed in lower part in tobacco and middle in tomato when seedlings, but they dispersed throughout the whole fully grown tomato plants with irregular inclined to the under, outer stretched leaves. Bemisia tabaci was also caught massively in yellow sticky traps in height of 30 cm above soil, and 30 cm above a plant. There was no attraction effect by flower model traps and fly catcher. When introduced with different densities (0, 10, 50, 100, 200, and 400) in square cages, the B. tabaci do damaged at the densities of 200 with mild and 400 with severe symptom on plants in two weeks and four weeks after inoculation.

This study was conducted to investigate specific stages and distribution of overwintering nymphs of green rice leafhopper, Nephotettix cincticeps by measuring head capsule width. The nymphal head capsule width of the 1st instar to the 5th instar was 0.381, 0.502, 0.673, 0.979 and 1.128 ㎜, respectively. Its coefficient variation was 5.3, 4.0, 3.0, 4.5 and 5.3%, respectively. Growth ratio of each instar was not significantly different among 2nd to 4th instars as 1.31 to 1.34, but for the 5th instar it decreased as 1.28. The logarithm of the nymphal head capsule width was regressed as a function of the stage number of insects, resulting in LogY = 1.4627 + 0.1192X (r² = 0.9993). Also fitness to the Dyar’s law for the nymphal head capsule width of each instar was 98% or over and the Dyar’s constant (K) was 1.316. The occurrence of N. cincticeps was maximum at the end of January with 195 individuals/0.25 ㎡. The most abundant instar in the overwintering N. cincticeps population was 4th instar accounting for over 90%. Population of the 5th instar began to increase from mid-March, and adults began to occur in early April.

This study was conducted to determine whether trichome density affects the oviposition behavior of adult female Tetranychus urticae Koch on host plant leaves. Experiments were conducted with twenty replications on the leaf discs of each plant (Pear, 'Niitaka'; Apple, 'Fuji'; Strawberry, 'Meahyang'; 3cm diameter) at 25℃, 60-70% RH and a photoperiod of 16:8 (L:D) h. One female T. urticae was placed on each disc. The number and locations of laid eggs were recorded at 24 h intervals until T. urticae died. The trichomes were distributed along the midrib of abaxial surface of pear leaves but were evenly distributed on that of apple and strawberry leaves. Eggs were mostly laid along the midrib of pear leaf disc, but eggs were laid not only along the midrib but also randomly over the leaf disc of apple and strawberry. Therefore, it appeared that T. urticae preferred to lay eggs on the specific location where trichomes were densely distributed. Further study is needed to quantify how different distribution patterns of T. urticae eggs on different plant leaves affect the efficacy of predatory mites to control T. urticae.