• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(5)
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• pp.189-192
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• 2002

This paper has been studied the movement of snake robot. In this paper we developed a simulator to simulate the creeping locomotion of a snake robot. This Robot makes possible to analyze the creeping locomotion with the normal-direction slip coupled to gliding along the tangential direction. Using the nonslip condition of the wheels, the robot gains propulsion by means of constrained forces on the wheels caused by bending the joints. The results of simulations show that smooth lateral undulatory motion is achived.

• 한국산림과학회지
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• 제105권4호
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• pp.435-440
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• 2016

경상남도 하동군 옥종면 청룡리 땅밀림 산사태지의 인장균열 형성과 그에 따른 토양 물리성 변화를 조사한 결과, 주 인장균열과 국부적 인장균열의 단차와 절취경사는 차이가 없는 것으로 나타났다. 토양 물리성 변화의 경우에는 토양깊이 31~40 cm의 액상이 유의적 차이를 나타내었다. 한편, 액상은 미교란지와 교란지에서 유의적 차이가 나타났는데, 이는 입지요인에 의한 것으로 판단되다. 따라서 하동군 옥종면의 땅밀림 산사태지에서는 붕괴과정 중 토괴가 일체로 미끄러지며, 단적으로는 토양 물리성 변화도 크게 나타나지 않는 것으로 나타났다. 이에 따라 땅밀림 산사태에 대한 보다 연계성 있는 연구가 진행되어야 할 것이다.

• ALGAE
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• 제25권3호
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• pp.141-153
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• 2010

Seagrass epiphyte blooms potentially have important economic and ecological consequences in Tampa Bay, one of the Gulf of Mexico's largest estuaries. As part of a Tampa Bay pilot study to monitor the impact of environmental stresses, precise characterization of epiphyte diversity is required for efficient management of affected resources. Thus, epiphyte diversity may be used as a rational basis for assessment of ecosystem health. In May 2001, epiphytic species encompassing green, brown and red macroalgae were manually collected from dense and sparse seagrass beds of Thalassia testudinum and Syringodium filiforme. A total of 20 macroalgal epiphytes, 2 Chlorophyta, 2 Phaeophyta, and 16 Rhodophyta, were found on T. testudinum and S. filiforme seagrass at the four sampling sites (Bishop Harbor, Cockroach Bay, Feather Sound, and Mariposa Key). The Rhodophyta, represented by 16 species, dominated the numbers of species. Among them, the thin-crusted Hydrolithon farinosum was the most commonly found epiphyte on seagrass leaves. Species number, as well as species frequency of epiphytes, is higher at dense seagrass sites than sparse seagrass sites. Four attachment patterns of epiphytes can be classified according to cortex and rhizoid development: 1) creeping, 2) erect, 3) creeping & erect, and 4) erect & holding. The creeping type is characterized by an encrusting thallus without a rhizoid or holdfast base. Characteristics of the erect type include a filamentous thallus with or without a cortex, and a rhizoid or holdfast base. The creeping and erect type is characterized by a filamentous thallus with a cortex and rhizoid. A filamentous thallus with a cortex, holdfast base, and host holding branch is characteristics of the erect and holdfast attachment type. This study characterized each species found on the seagrass for epiphyte identification.

• 아시안잔디학회지
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• 제24권2호
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• pp.117-124
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• 2010

한지형 잔디 6종류의 45품종에 대하여 여름철 갈색마름병의 발생과 잔디생존율을 평가하였다. 갈색마름병의 발생율은 7월에 2회 조사를 하였으며, 잔디생존율은 8월과 9월사이에 조사를 하였다. 여름철 갈색마름병의 발생율과 잔디생존율에서 잔디종류별 품종 간에 통계적인 유의성이 차이가 크게 나타났다. rDNA ITS 동정에 의한 갈색마름병원균인 Rhizoctonia spp. 와 Pythium aphanidermatum에의한발병율은 Creeping Bentgrass 품종과 Chewings fescue 품종이 가장 약하였다. 잔디의 생존율도 Creeping Bentgrass 품종과 Chewings fescue 품종이 가장 약하였다. Kentucky bluegrass종은 20 품종 중 "Nuglade", "Cabernet", "Midnight II" 및 "Beyond" 품종이 생존율이 가장 좋았고, Tall fescue 종은 "Double sentry"와 "Inferno" 두 품종에서 생존율이 가장 좋았으며, Perennial ryegrass 종은 2품종 중 "Accent II" 품종이 생존율이 가장 높았다.

• 아시안잔디학회지
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• 제17권2_3호
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• pp.87-97
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• 2003

The growth characteristics of creeping bentgrass seeded in the seaside landfill golf course are as follows. 1. As a result of analysis on the chemical characteristics of soil mixture used for turfgrass ground in this experiment, soil pH was 7.9, which is somewhat higher than the creeping bentgrass reference value of pH 5.5∼6.5; T-N(%) was 0.02, which is proper for the reference value, and trace element too lacked. 2. The cultivar with the fastest water infiltration was Seaside II recorded as 226.2cm/sec, while that with the slowest water infiltration was Pennlinks recorded as 141.1 cm/hr which was too faster than the USGA water infiltration reference value of 15∼30cm/hr. For the surface hardness of turfgrass ground with different cultivars, no statistically significant variation was found between the Penncross grass and the Pennlinks recorded as 18.6mm and 19.1 mm, respectively. The soil penetration was the highest in Pennlinks recorded as 7.6kg/$\textrm{cm}^2$ and lowest in Penn A-1 as 6.1kg/$\textrm{cm}^2$. 3. As a result of evaluation on visual quality at the early stage of growth, Penncross showed the most excellent visual quality compared to the others. However, Penn A-1 showed the most excellent visual quality at a late stage of growth around Sep. 17, 2003, and it was also excellent in the evaluation of visual color. Seaside II showed higher density around the root and the longest root length and was highly resistant to salt compared to others, but the initial sprouting rate was not satisfied, and the visual quality in the summer season was inferior to others. 4. As a result of measurement of the traffic injury, Penncross showed the most tolerant to the traffic stress and Pennlinks showed the most susceptible.

• 아시안잔디학회지
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• 제17권1호
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• pp.13-17
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• 2003

본 실험은 종합 토양개량재 KOB-Soil이 한지형 잔디의 생육에 미치는 영향을 구명하기 위해 Creeping bentgrass 및 Kentucky bluegrass (KB) 75%+perennial ryegrass(PR) 25%로 조성된 잔디면에서 실험을 수행하였다. 실험기간은 2001년 9월 1일∼2002년 8월 31일까지 강원도 정선군 사북읍, 강원카지노 리조트 실험포 화절령 지구에서 수행하였다. 처리는 USGA 지반의 혼합층에 모래 80%+피트 20%, 모래80%+KOB-Soil 1호 20% 및 모래 80%+KOB-Soil 2호 20%로 하였다. 조사항목으로 잎 길이(mm), 잎 수, 잔디품질, 뿌리길이(mm)를 조사하였다. 종합 토양개량재 KOB-Soil은 한지형 잔디인 크리핑 벤트그래스와 Kentucky bluegrass (KB) 75%+perennial ryegrass(PR) 25%의 잎 길이, 잎 수, 잔디품질, 및 잔디 뿌리 생육을 촉진하는 것으로 나타났다. 특히 KOB-Soil에 있어 크리핑 벤트그래스와 KB 75%+PR 25%의 생육은 KOB-Soil 1호가 2호보다 우수한 것으로 나타났다. 이는 KOB-Soil 1호는 BFS-1000이 ㎥당 2.76L 수량 및 Root grow(황산고토를 주성분으로 하는 천연 토양개량제)가 ㎥당 0.48L 의 수량이 함유되어 있기 때문으로 판단된다.

• 아시안잔디학회지
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• 제2권1호
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• pp.5-30
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• 1988

The object of this experiments was to know the salt tolerance of Fults and other lawn grasses. Fults, Olympic (Tall fescue, Festuca arundinacea Schred), Ceeping red fescue, Kentucky bluegrass and Zoysia grass (Z. japonica S.) were grown in hydroponics with vermiculite at various concentrations of NaCl. Hoagland's solution was used as the basic solution (control), and the concentrations of Cl to it were 1000, 2000, 3000, 4000 and l5OOOppm, respectively. Each was cultivated under the circumstances during 2 months. The results obtained are summarized as follows: 1.The growth of Fults, Olympic, Creeping red fescue and others were better at Cl lOOOppm than control. In the 5OOOppm application, Fescues become worse and 23.9% of them were withered. In concentration of Cl above 9OOOppm, it was impossible to live. 2.In the l0000~l1000ppm application, Olympic and Kentucky bluegrass were become worse and most of them died. 3.Fults were almost possible to live in the below of 9OOOppm, but they began to die in the above of 10000 ppm. 4.With the increasing concentration of Cl, plants were dwarfed and the number of stems, leaves and roots were reduced, but it was especially observed that the number of stolons of Creeping red fescue were increased at 1000~4000ppm. 5.Fults grass was the most salt tolerant turfgrass, but was impossible to live at salt level of about 36 millimhos (Exchange NaCI conductivity-ppm). Among the grasses, according to salt tolerance, they were arranged as follows. Fults > Zoysia japonica S. > Ky belugrass > Olympic grass > Creeping red fescue 6.The number of leaves, stems, tillers, and dry weight of Olympic grass, Fults and others were increased more at Cl 1OOOppm application than control, but in the above 4OOOppm application, those of plants were decreased. 7.The productivity of all grasses under the experiments was increased at 3.l75millimhos (Exchange NaCi conductivity ppm) in the concentration of Cl. The each dry-weight of Olympic, Creeping red fescue, Kentucky bluegrass and Zoysia grass was decreased at 8.85millimhos, and the weight of Fults grass was also decreased remarkably at 12.20millimhos. 8.As the result of this experiments, most plants grow normally at low concentration of NaCI-l000ppm. That seems to stimulate more the grasses to grow than non-salt.

• The Plant Pathology Journal
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• 제15권2호
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• pp.112-118
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• 1999

Eleven species of Pythium were isolated from leaf blight symptoms on creeping bentgrass (Agrostis palustirs Huds.), Kentucky bluegrass (Poa pratenisis L.) and zoysiagrasses (Zoysia japonica Steud., and Z. matrella (L.) Merr.) planted on golf courses in Korea. Mycelial growth on potato carrot agar medium under various temperature conditions indicated that Pythium species obtained in this study could be divided into four groups based on their responses to temperature conditions. P. vanterpoolii was found to favor low temperature conditions with the optimum temperature of $25^{\circ}$, whereas P. aphanidermatum and P. myriotylum favored relatively high temperature conditions with the optimum temperature of $35^{\circ}$. Other species including P. arrhenomanes, P. catenulatum, P. graminicola, P. oligandrum, P. rostratum, P. torulosum, and P. ultimum were the intermediate group with the optimum temperature of 25~$35^{\circ}$. P. periplocum was similar to the intermediate group but the minimum temperature for its mycelial growth was $15^{\circ}$, which was approximately $5^{\circ}$ above that for the intermediate Pythium spp.group. In the pathogenicity tests conducted in the lab using potted plants, P. aphanidermatum, P.a arrhenomanes, P. catenulatum, P. graminicola, P. myriotylum, P. periplocum, P. rostratum, P. torulosum, P. ultimum, and P. vanterpoolii were found to be pathogenic to creeping bentgrass and Kentucky bluegrass. P. aphanidermatum, P. catenulatum, and P. graminicola were frequently isolated from leaf blight symptoms of creeping bentgrass and Kentucky bluegrass in golf courses during the warm and humid periods in July-August. On the other hand, P. vanterpoolii and P. torulosum were frequently isolated during the cool and humid periods in March-May, suggesting both species might be the major causes of leaf blight occurring in the spring time. Zoysiagrass was susceptible to P. arrhenomanes and the heterothallic Pythium sp. (Ht-F), showing stem and crown rot of turf-grasses at poorly drained areas under coool and humid or rainy conditions. P. oligandrum and the heterothallic Pythium sp. (Ht-L) isolated from creeping bentgrass were avirulent to all species of turfgrasses tested in this study.

• 아시안잔디학회지
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• 제9권3호
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• pp.235-252
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• 1995

Turfgrass Rhizoctonia blight is a severe disease in golf courses in Korea. Attempts were made in 1989 to 1994 to identify the Rhizoctonia species associated with turfgrass blights and also to examine their epidemiology. A total of 120 Rhizoctonia isolates collected were identified as R. solani AG1, R. solani AG2-2, R. cerealis(AG-D) and R. oryzas from brown patch, large patch, yellow patch and white patch, re-spectively. R. solani AG1 was mostly associated with brown patch of cool-season grasses. and most frequently isolated in June through July and also in September. R. solani AG2-2 was isolated exclusively from zoysiagrasses from April to November, most frequently in June through July and October through November. R. cerealis was isolated frequently from both creeping hentgrass in March through April and in November, and zoysiagrass in April and July. Thermophilic R. oryzae was isolated only from creeping bentgrass in August, although with very low frequency. R. solani AG2-2 was strongly pathogenic specifically to Korean lawngrasses(Zoysia japonica, Z.matrella, Z. tenuifolia), but non-pathogenic to creeping bentgrass(Agrostis palustris), bermudagrass (Cynodon dactylon), Kentucky bluegrass(Poa pratensis), perennial ryegrass(Lolium prenne), and creeping red fescue(Festuca rubra subsp. ruhra L.). R. cerealis was strongly pathogenic to zoysiagrass and bentgrass only, but was isolate-specific i.e., from non-pathogenic to pathogenic, for other turfgrasses. The mycelial growth was optimum at relatively high temperature ranges of 25~30$^{\circ}C$ for R.solani AG1, AG2-2 and R. oryzae, while the mycelial growth of R. cerealis was initiated at $^{\circ}C$ and almost ceased at or above $^{\circ}C$.

• 아시안잔디학회지
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• 제9권3호
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• pp.253-260
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• 1995

This study is aimed to understand the effects of temperature, light and GA soaking treatment on the seed germination of perennial ryegrass 'Dandy', creeping hentgrass 'Penlinks', tall fescue 'Arid' and Kentucky hluegrass 'Nasaw'. These experiments are carried in vitro, and their results obtained are summarized as the followings ; The optimum temperature for seed germination of perennial ryegrass 'Dandy' was found to he ranged at 20~30$^{\circ}C$, and the optimum temperature for germination of creeping bentgrass 'Penlinks', tall fescue 'Arid' and kentucky bluegrass 'Nasaw' seeds was found to be ranged at 20~25$^{\circ}C$, whereas the germination percentage under the below or above temperature of this range decreased. The germination of perennial ryegrass 'Dandy' and tall fescue 'Arid' seeds showed no effect on light, and while the germination percentage of creeping hentgrass 'Penlinks' increased more highly under the dark condition than under the light condition. The germination percentage decreased according to the higher temperature. The germination of Kentucky bluegrass 'Nasaw' seeds increased more highly under the dark condition than under the light condition at 20~25$^{\circ}C$, whereas the germination percentage under the dark condition at 15$^{\circ}C$ and 30$^{\circ}C$ decreased. In case of GA soaking treatment of seeds, all the cool season turfgrasses tested showed their own promoting effects on seed germination. The early germination of tall fescue 'Arid' was good without the soaking times. Creeping bentgrass 'Penlinks' and perennial ryegrass 'Dandy' had re-spectively the highest germination percentage at 10min and 1hr soaking treatment, and the longer the soaking time, the lesser the germination percentage. Kentucky bluegrass 'Nasaw' obtained the best results at 24has soaking treatment, and the longer the soaking time, the better the ger-mination percentage.