• Structural Engineering and Mechanics
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• v.52 no.6
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• pp.1069-1084
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• 2014

The long-term performance of plates resting on viscoelastic foundations is a major concern in the analysis of soil-structure interaction. As a powerful mathematical tool, fractional calculus may address these plate-on-foundation problems. In this paper, a fractionalized Zener model is proposed to study the time-dependent behavior of a uniformly loaded rectangular thin foundation plate. By use of the viscoelastic-elastic correspondence principle and the Laplace transforms, the analytical solutions were obtained in terms of the Mittag-Leffler function. Through the analysis of a numerical example, the calculated plate deflection, bending moment and foundation reaction were compared to those from ideal elastic and standard viscoelastic models. It is found that the upper and lower bound solutions of the plate response estimated by the proposed model can be determined using the elastic model. Based on a parametric study, the impacts of model parameters on the long-term performance of a foundation plate were systematically investigated. The results show that the two spring stiffnesses govern the upper and lower bound solutions of the plate response. By varying the values of the fractional differential order and the coefficient of viscosity, the time-dependent behavior of a foundation plate can be accurately captured. The fractional differential order seems to be dependent on the mechanical properties of the ground soil. A sandy foundation will have a small fractional differential order while in order to simulate the creeping of clay foundation, a larger fractional differential order value is needed. The fractionalized Zener model is capable of accounting for the primary and secondary consolidation processes of the foundation soil and can be used to predict the plate performance over many decades of time.

• Research in Plant Disease
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• v.16 no.1
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• pp.94-96
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• 2010

In May of 2004 through 2007, Leptosphaerulina leaf blight caused by Leptosphaerulina trifolii occurred on Kentucky bluegrass (Poa pratensis) at golf courses in Gangwon Province, Korea. Symptoms on the turfgrass caused by L. trifolii were leaf blights, dying from the leaf tip downwards to the crown, which appeared patches in the field because of local pockets of severely infected (blighted) grass. Perithecia were produced on old or weak leaves, including club-shaped asci, each of which contained 8 pale brown muriform ascospores with cross and longitudinal septa. Ascospores of the fungus isolated from the diseased leaf tissue and cultured on potato-dextrose agar (PDA) were muriform multicellular (composed of 3-6 cells) and $23.4-40.5{\times}7.8-15.6{\mu}m$ in size with 3-4 transverse and 0-3 longitudinal septa, which were morphologically identical to L. trifolii reported previously. DNA sequences of ribosomal RNA gene (internal transcribed spacer) of the fungus were homologous with similarity of 99% to those of L. trifolii isolates in GenBank database, confirming the identity of the causal agent of the disease. Pathogenicity of the fungus was also confirmed on the creeping bentgrass by Koch's postulates. This is first report of Leptosphaerulina leaf blight on turfgrass caused by L. trifolii in Korea.

• Korean Journal of Organic Agriculture
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• v.6 no.1
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• pp.133-149
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• 1997

Recently, the importance of management and cultivation of grasses has been increased in Korea. Among these cultural practices, the appropriate control of diseases is considered more important than other cultivation techniques such as fertilization and irrigation. The damages of brown patch and large patch caused by Rhizoctonia spp. and Pythium blight caused by Pythium spp. are serious in the major cultivation area of turfgrass in Korea. Since these diseases are difficult to control by agrochemicals, the damages are very serious if these are occured. The periodic spray of agrochemicals, to protect and control these diseases could make some problems of toxicity and environmental pollution as well as rising of non-target diseases. Therefore, the biological methods to control diseases have been required to decrease problems resulted from overuse of agrochemicals, to conserve natural ecosystem, and to control effectively diseases of grasses in the long period. The number of studies about biological control using antagonistic microorganisms have been increased for last half century. However, the application of biological control method has been very limited. In this study, thirteen isolates of R. cerealis, 8 isolates of R. solani and 3 isolates of Phthyn spp. have been isolated from diseased turfgrass in golf course and grass-culture area that have patch and wilting symptoms of zoysia grass and creeping bentgrass. Isolation frequency of R. cerealis and R. solani was high in especially zoysiagrass, while Pythym spp. was isolated from bent grass at low frequency but showed high pathogenicity. Totally, 205 isolates of soil microorganisms were isolated in this study as primary antagonistic microorganism by Herr's triple agar layer plate and dual culture method using rhizosphere of grasses, soil of crop field as the source of antagonistic microorganisms. Among the 205 isolates, 23 isolates were actinomycetes and 182 isolates were bacteria. All of the actinomycetes were isolated by Herr's method. Antagonistic effect of primary isolated microorganisms was tested for in vitro mycelial growth inhibition against pathogenic fungi isolated from grasses and for inhibition of disease occurrence in 24 well tissue culture plate and pot experiment. Then, four isolated of bacteria which are BG23, BG74, BG136 and BG171 were selected as antagonistic microorganisms against soil-born pathogenic fungi of bentgrass.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.11 no.1
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• pp.88-98
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• 2011

Lesch-Nyhan syndrome is a X-linked recessive disorder caused by a deficiency of the enzyme hypoxanthine-guanidine phosphoribosyltransferase (HPRT), enzyme to recycle purines. Case history: born induced vaginal delivery at 40 weeks complicated by premature membrane ruputure, body weight 2.820 gm. He showed failure to thrive showing severe protein aversion like milk products and pink daper. Developmental delay revealing rolling over at 10.5 month, followed by regression. Seizure at 2 months, His poor oral feeding was lifelong problem. Weak crying, spastic, choreoathetoid movement. Self mutilating behavior noted and diagnosed at age 3 years. No family history of consanguinity and neurological disorders. Method: Laboratory test, physical exam, imaging study and molecular. Clinical follow up Treat ment with allopurinol. Result: uric acid 10.5 mg/dL (N 3.5-7.9), APRT 151.1uM/ min/ml pro(25.7-101), HPRT 7.6 (N 233.5-701) and c.151C>T hemizygote (p,Arg51X). Abdominal sonogram showed staghorn calculi in both kidneys, brain MRI brain atrophy. Clinical follow up showed, seizure at 2 mo, developmental delay (head control and, rolling over at at 11mo, pointing body part at 2 yr 7 mo, eye hand coordination at 2 y 11mo,creeping at 3 y 7 mo, speaking words at 6 y 6 mo ),and developmental regression at 3 yr of age. Sleeping problem including insomnia and severe constipation. Self mutilating behavior (lip bite) started at 2.5 yr, neurologic sx including intermittent upward gaze accompanied by swallowing difficulty at 3 y 7 mo grand mal seizure at 4.5 yr and spastic extremity and trunchal hypotonia and choleoathetoid movement and ataxia at 6.5 yr. Scoliosis with severe spasticity at 9 yr 9 mo. Acute life threatening episode with irregular breathing at 9 yr and 9 mo, Emaciation and nephrolithiasis and recurrent pneumonia. Died suddenly at 10 yr 3 mo. Conclusion: life long feeding problem, chronic gut motility dysfunction, sleeping difficulty and progressing neurologic deterioration and nephrolithiasis despite normal serum uric acid maintence by allopurinol treatment.

• Archives of Reconstructive Microsurgery
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• v.3 no.1
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• pp.9-15
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• 1994

It is difficult to obtain a satisfactory bony union of large bone defect secondary to trauma, tumor resection, congenital pseudarthrosis of tibia and bony metaplasia following infection with conventional methods. Conventional nonvascularized autologous bone graft do not provide adequate large amounts of donor bone and usually undergo necrosis or nonunion due to lack of vascular nutrition. Currently, advanced in microsurgery have made it possible to provide a continuing circulation of blood in bone grafts so as to ensure viability. With the nutrient blood supply preserved, healing of the graft to the recipient bone is facilitated without the usual replacement of the graft by creeping substitution. Thus, the grafted bone is achieved more rapid stabilization without sacrificing viability. We reviewed 11 cases of vascularized fibular grafts which were performed from December 1982 to January 1993 and the following results were obtained: 1. Large bone defects with chronic osteomyelitis secondary to trauma were could be successfully treated by the vascularized fibular transfer. 2. In our experience, the vascularized fibular transfer was thought to be one of good methods of treatment for congenital pseudathrosis of tibia. 3. Complete tumor resection was followed by a free vascularized fibular transfer, resulting in good functional improvement, without local recurrence. Long bone defect secondary to bony dysplasia was could be reconstructed by the vascularized fibular transfer. 4. The transferred vascularized fibula had been hypertrophied with bony union during follow-up period and there was no resorption of the grafted fibula.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.2
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• pp.77-84
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• 2002

The alpine grassland vegetation at the west slope of Cheungseuk-bong on Mt. Paektu was investigated by Penound-Howard's cover-degree method. The floristic composition of the alpine grassland from 1,800m altitude to the top of mountain were 30 species, 2 subspecies, and 3 varieties, and most of the plants were short(height 2∼13㎝) perennial herbs and shrubs. The highest cover degree of the species in the alpine grassland zone were Ligularia jamesii, Veratrum patulum and Thalictrum aquilegifolium (1,800∼2,l00m), Vaccnium uliginosum and Rhododendron aureum (2,100∼2,l00m), and Rhododendron aureum (2,300∼2,600m). Life form of the plants were 7 species of Chamaephyte, 27 species of Hernicryptophyte, and 1 species of Geophyte. Among the presented plants, 19 species were at flowering stage. Trollius hondoemsis, Trollius japonicus, Liguiaria jamesii and Lloydia serotina were peak at flowering.

• Korean Journal of Plant Taxonomy
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• v.45 no.4
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• pp.318-322
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• 2015

A new species, Fimbristylis jindoensis J. Kim & M. Kim, is herein named and described. It is found on wet lowland mountain slopes in Jindo-gun, Jeollanam-do, Korea. Fimbristylis jindoensis shares several characteristics (long-creeping rhizomes, oblong spikelets, brown scales, and three-sided achenes) with the related species F. pierotii Miq. It is, however, distinct from F. pierotii, which has terete culms with five to six furrows that are 9-48 cm tall, flowers in June to July, a dry grassland habitat, fewer than ten spikelets, and simple anthela inflorescences. In contrast, the new species has shallow furrowed oval culms which are 57-93 cm tall, flowers in July to August, a wet mountain habitat, more than twenty spikelets, and compound anthela inflorescences.

• Korean Journal of Plant Resources
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• v.25 no.2
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• pp.257-270
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• 2012

The taxonomic relationship of 3 taxa in $Carex$ sect. $Siderostictae$ were revealed by morphological and molecular studies. The morphological characteristics of Korean $Carex$ siderosticta Hance, which is a type species of sect. $Siderostictae$, was first reviewed in comparison with previous records in order to identify the difference. Then the distribution map of this species was formulated through previous floral literatures and voucher specimens. Although the leaf shape which is represented by length/width ratio showed a great variation depending on habitat condition, the rhizome creeping patterns, the presence of hair on the surface leaf margin and perigynium were shown to be good diagnostic characters to define delimitation of species level. The results from molecular study supported $C.$ $ciliatomarginata$ Nakai should be ranked independently on species level.

• Journal of Korean Society of Forest Science
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• v.94 no.6
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• pp.377-386
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• 2005

This study was carried out to analyse the landslide characteristics by ground investigation, borehole image processing system, field seismic test, laboratory test and ground stability analysis at the landsliding area occurred in Maeri, Sangdong-myeon, Gimhaesi, Gyeongsangnam-do. Region I needs to install data logger system to monitor a land displacement during the heavy rainfall events because the region can be liable to occur the land slide by land creeping. It is needed to restore rapidly, if the land displacement occurs in Region I. Region II needs to monitor and repair because of the possibility of slope failure by long-term soil loss. Region III needs constructions to remove ground runoff and ground water to be infiltrated from talus. Region IV where is a stable region, needs to be protected from land cutting or other man-made damage.

• Asian Journal of Turfgrass Science
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• v.24 no.1
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• pp.36-44
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• 2010

We were investigated turf color and Normalized Difference Vegetation Index (NDVI) to affect greenup promotion of 38 cultivar in 5 species for spring season, most popularly used in Korea golf courses. Kentucky bluegrass (Poa pratensis L.), tall fescue (Festuca arundinacea Schreb), creeping bentrgass (Agrostis palustris Huds), perennial ryegrass (Lolium parenne L.) and zoysiagrass (Zoysia spp.) cultivar had higher leaf color for greenup promotion in Ami, Amx and Oligo than Con treatment and there were also significantly difference among treatments. Turfgrass NDVI also showed significant difference among cultivars in species. Spray of Ami, Amx and Oligo has the higher value of turf NDVI than Con. Based on our results, green up fast during spring season may affected much more with application of Ami, Amx and Oligo than Con.