• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.8 no.1
• /
• pp.13-21
• /
• 1997

In this paper, the oscillator type active antenna used as an element of active phased array antenna is designed and fabricated using slot coupling. The radiating element and active circuit are fabricated on each layer respectively and coupled electromagnetically through slot on the ground plane. This structure can solve the problems such as narrow bandwidth of microstrip antenna, spurious radiation by active circuits, and spaces for integration of the feeding circuits which are caused by integrating antennas with oscillator circuits in the same layer. The active antenna in this paper, the oscillation frequency can be tuned linearly by controlling the drain bias voltage of FET. The frequency tuning range is between 12.37 GHz to 12.65 GHz when bias voltage is varied from 3V to 9V, thus frequency tuning bandwidth is 280 MHz (2.24%). The output power of antenna is uniform within 5dB over frequency tuning range. Therefore this active antenna can be used as an element of linear or planar active phased array antennas.

• Journal of Gastric Cancer
• /
• v.5 no.1
• /
• pp.47-51
• /
• 2005

Eosinophilic gastroenteritis is a rare clinicopathologic entity of unknown etiology with a variety of digestive symptoms. The pathogenesis is poorly understood. Diagnostic criteria include demonstration of eosinophilic infiltration of the affected bowel wall, lack of evidence of extraintestinal disease, and exclusion of various disorders that could mimic similar conditions. The disease might involve any area of the gastrointestinal tract from the esophagus to the rectum, but the stomach and the proximal small bowel are most commonly affected. The clinical features depend on which layer and site are involved. We report the case of a 59-year-old male patient with a 3-week history of post-prandial vomiting with malnutrition and weight loss. An abdominopelvic CT showed a gastric outlet obstruction with diffuse wall thickening, as with linitis plastica. Three gastrofiberscopic biopsies showed chronic gastritis. We carried out a radical total gastrectomy with D2 lymph node dissection. The pathologic report revealed a mural type eosinophilic gastritis with a marked hypertrophic scar formation at the proper muscle layer. We report this case with a brief review of the literature. (J Korean Gastric Cancer Assoc 2005;5:47-51)

• Korean journal of applied entomology
• /
• v.44 no.4 s.141
• /
• pp.317-323
• /
• 2005

This study was conducted to survey plant-parasitic nematodes and their damages on Codonopsis lanceolata Trautv at 116 fields of 15 major cultivation areas in Korea. Among the 9 plant-parasitic nematode genera detected in the fields, Ditylenchus citri, Meloidogyne hapla, M. incognita, Pratylenchus neglectus, Tylenchorynchus clayton were identified. M. hapla Chitwood showing the highest field infection rate of 61.9% followed by Tylenchus spp. 16.1%, Pratylenchus neglectus 7.8%, Ditylenchus citri 5.1%, and Helicotylenchus sp. 5.1%. Average field infection rate of root-knot nematodes in 2-year-old C. lanceolata was 67.0%, and the average plant infection rate was 60.2%. The average yield decrease rate was 10%. The damage rate by the root-hot nematode increased as the cultivation year extended in Jeonbuk province, and the damage was also higher in flat land than in mountainous areas.

• Korean journal of applied entomology
• /
• v.25 no.4 s.69
• /
• pp.201-207
• /
• 1986

This study was conducted to investigate the host plants in greenhouse, developmental periods at different temperatures and distribution patterns on cucumber of the greenhouse whitefly, Trialeurodes vaporariorum(TV) in $1984{\sim}1985$. Host plants of 39 species belonging 27 families only in the greenhouse were recorded in 1984. Longevity of adult was 26.8 days and number of eggs per female was 305 eggs at $25^{\circ}C$. The eggs, larval and pupal periods were 8.2, 8.3, 7.5 days respectively at $25^{\circ}C$. The threshold temperature of development from egg to larva was $8.8^{\circ}C$. Survival rates from eggs to adults at $22^{\circ}C,\;25^{\circ}C,\;30^{\circ}C$ were 70.3%, 58.0% and 66.4%, respectively. Adults and eggs were found only on the apical leaves of cucumber plants within 40 days after transplanting. On the other hand, larva distributed on the middle leaves and pupa on the lower leaves.

• Korean Journal of Environment and Ecology
• /
• v.31 no.1
• /
• pp.30-41
• /
• 2017

Mammals in Korea have been studied in various fields such as animal science, veterinary medicine, laboratory animal science, ecology, and genetics. As the importance of biodiversity has been emphasized recently, conservation and management of mammals have attracted much public attention. However, in spite of such an increase in scientific research and public interest, it is still difficult to find a report or summary to grasp the trend of mammalian research in Korea. The purpose of this study is to provide the basic data for future plans of the detailed research area and the related policies by grasping the research trends of mammals in Korea. Using text-ming and co-word analysis, we analyzed 392 mammalian research papers published in Korean national journals as of 2015. Our results showed that the number of mammalian research papers published in Korea has gradually increased and that the research target species have also become increasingly diverse. The major research areas identified through text-mining and co-word analysis are (1) evolution/phylogenetics/genetics, (2) environmental science/ecology, (3) embryology/reproductive biology/cell biology, (4) veterinary medicine related to parasites, (5) parasitology related to rodents, (6) bacteriology/virology, (7) anatomy/cell biology/laboratory animal science, (8) veterinary science related to morphology and anatomy, (9) animal science, (10) marine mammalogy, and (11) Chiroptera (bat) research. Environmental science/ecology has been the most active field among the 11 research areas in recent times, and the proportion of research has increased sharply compared to the past. Environmental science/ecology is the core of biodiversity conservation, and as the importance of biodiversity has been emphasized in recent years, researchers' interest in mammal ecology appears to have increased. We expect that the results of this study will be useful for future research plan and related policies on mammals in Korea.

• Korean journal of applied entomology
• /
• v.45 no.2 s.143
• /
• pp.195-200
• /
• 2006

This study was carried out to clarify the biologies and morphological characteristics of Rhynchaenus sanguinipes. Also some chemicals were tested to screen the effective insecticide for the control of the species. Up to date, Zelkova serrata has been hewn as host plant of Rhynchaenus sanguinipes, which shows serious damage in this country. In the present study, Ulmus pumila was first found as host plant in this study. Body lengths of larvae, pupa and adult were 4.53$\pm$0.30 mm, 3.30$\pm$0.42 mm and 2.96$\pm$0.12 mm, respectively. The overwintered adult of the species emerged on early April to late April, and adult of nekt generation emerged on early May to late May, Pupal periods were 10, 7.2, 5.1 and 4 days on 16, 20, 24 and 28$^{\circ}C$, respectively. The lower developmental threshold temperature was 5.8$^{\circ}C$. Four braconid parasitoids were found as natural enemies, which emerged mainly on late April to early June. Insecticidal activities with treatments of fenitrothion 50% EC, indoxacarb 30% WG, ethofenprox 20% EC and thiacloprid 10% SC was investigated against adult of R. sanguinpes, and they showed >90% mortality.

• Korean journal of applied entomology
• /
• v.2
• /
• pp.47-54
• /
• 1963

The chestnut gall wasp, Dryocosmus kuriphilus $Y^{ASUMATSU}$, has been recently distributed and chestnut trees have teen seriously damaged by this insects in Korea. However, this insect pest has not been investigated in Korea. This paper gives an account of field and Laboratory observations on the seasonal occurrence and the life history of the chestnut gall wasp, and the damage of the chestnut trees by. its insects. This study was carried out at Chungchungpukdo, Kangwon-do and Kyungi-do in Korea, from 1961 to 1963, inclusive. 1. The Chestnut gall wasp (Dryocosmus kuriphilus $Y^{ASUMATSU}$) has one generathion per year and females are only known. 2. The adult wasps were observed from late June to late July with peak of wasp emergence about early and middle July. Most of new adult wasps were coming out from, the galls in the morning rather than the afternoon. 3. Each wasp produced auerage 198.5 eggs and about 4.89 eggs was observed in each bud of the chestnut tree. 4, The egg period of wasps was about 30 days and they were hatching from July to August. 5. The larval period of wasps were from middle of August to middle of next June and pupation took places about early June to middle of July. 6. The adult wasps were ovipositing into the buds and from early May next year, galls were growing. They caused stunting of growth and no fruiting or dying of the chestnut tries. 7. The first observation of the wasp was made at Chaechun of Chungchung-pukdo in 1958. Up to 1963 this insects are distributed in Kangwon-do, Kyunggi-do, north part of Chungchung-pukdo and north part of Kyungsangpukdo

• Korean journal of applied entomology
• /
• v.21 no.3 s.52
• /
• pp.113-122
• /
• 1982

Appressorial formation of Pyricularia oryzae on leaves showed no marked difference between highly resistant Tongil and susceptible Norm No. 6. Race N-2 of the blast fungus penetrated directly into motor cells of susceptible cultivar Norm No. 6, later extensively spreading hyphae were developed, while in the cultivar Tongil, after penetration, no further hyphal extension resulted. In discoloration of infected tissues, the highly resistant cultivar Tongil not only discolored rapidly, but also the percentage of discolored cells was higher than the susceptible cultivars, Jinheung and Norm No. 6. The respiratory rate, was generally higher in infected tissue than in healthy tissue. No significant difference in the respiration rate of resistant Suwon No. 180 was not found between the infected and healthy leaf tissue, whereas, in susceptible Jinheung, a marked increase in respiratory rate was caused by blast infection. The respiratory rate increased at the appearance of the first visible symptom in all cultivars resistant or susceptible. Higher peroxidase activity was found in infected tissues as compared with healthy tissue. Peroxidase activity increased in resistant and susceptible reactions. Particularly, in resistant reaction, the increase of the activity was more pronounced. In highly resistant reaction, there was no difference in peroxidase activity between healthy and infected tissues. Ascorbic acid oxidase, hydroquinone oxidase and catechol oxidase had the same trend as the peroxidase. In contrast, activity of catalase rather decreased in leaf tissues infected with compatible races of the fungus.

• Korean journal of applied entomology
• /
• v.2
• /
• pp.16-21
• /
• 1963

The present study was undertaken to investigate the effects of different nitrogen source and rate on the growth of Fusarium oxysporum f. vasinfectum which is known to be a noticeable fungus causing the wilt disease of both sesame and cotton in Korea. From the results of this study, It was known that different N source and rate markedly affect the growth of Fusarium oxyspsrum f. vasinfectum Among four N sourses were used in this study, nitrate-N and urea-N were appropriate N source for the growth of fungus. Above all, nitrate N was the best N source because it is utilized in more extensive range of concentration in comparison with the other N source by the fungus, On the other hand, ammonia-N is of little avail for the growth of the fungus because of the formation of unusual colonies with wavy margin and bead-like mycelial cells in addition to marked reduction of mycelial growth and B sporulation of the fungus irrespective of concentration. Judging from the formation of such an abnormal colony and bead-like mycelial cell which is known to be a characteristic of 'staling-type' growth of fungi, the effect of ammonia-N on the growth of Fusarium oxysporum f. vasinfectum is similar to that of phenoxy componnds on some other fungi previously investigated by some workers. Ammonium and nitrate also was not considered to be an appropriate source for the growth of the fungus because of the formation of colonies with slight wavy margin and appreciable reduction of mycelial growth and sporulation in higher concentration than 50meq. , although much or less masking of the irregularity of colony occurs. Therefore, ammonia N alone or any other N combined with ammonia N is of little avail for the growth of Fusarium oxysporum f. vasinfectum.

• Korean journal of applied entomology
• /
• v.49 no.4
• /
• pp.409-416
• /
• 2010

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.