• Korean Journal of Weed Science
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• v.15 no.1
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• pp.30-38
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• 1995

Soil-applied pre-emergence herbicide, pyrazolate(4-(2, 4-dichlorobenzoyl)-1, 3-dimethyl pyrazol-5-yl-p-toluene sulphonate) induced, twist effect of shoots of barnyardgrass under dry conditions, and etiolated leaf and stem of that under water condition. Plant height and root length of rice broadcast on soil surface were similar to the untreated control, but plant height of rice drilled in soil was more inhibited than root length as compared with the untreated control, while development of barnyardgrass seedling was severely inhibited at 20 days after application. The inhibition rate was much higher under water condition than under dry condition, but difference in rice and barnyardgrass did not abserve. However, growth of transplanted rice shown to increase to the untreated control. Shoot and root fresh weight of rice broadcast on soil surface was increase as compared with the untreated control, and that of rice drilled in soil was not affected whereas that of barnyardgrass was severely inhibited by 42% and 41%, respectively. Under dry condition at 20 days after pyrazolate application while root growth of rice broadcast on soil surface under water condition was deadly inhibited and development of barnyardgrass was almost completely inhibited. On the other hand, microscopic studies showed that constriction of mesophyll cell by destruction of chloroplast of barnyardgrass were occurred only under dry condition, whereas damage of rice and barnyardgrass under water and transplanting condition were not observed. Anatomical change in the meristernatic region of rice and barnyardgrass was not occurred, and similar to intact plant regardless of cropping patterns.

• Journal of the Korean Wood Science and Technology
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• v.2 no.2
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• pp.22-24
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• 1974

1. Object and importance of the research. The exports of plywood are increasing annually and it has ranked first in the world market because of the high quality product developed and manufactured using modern techniques. However, it is known that the exports of the other wood products, except plywood, is inactive because of their low quality. Accordingly, to increase the exports of various wood products investigations were carried out on kiln drying techniques to improve the quality of the wood. 2. The details and scope of the research Wet wood should be kiln dried before use to prevent various drying defects such as distortion, shrinkage etc, which would develop after processing, and also wet wood is not suitable for cutting, gluing and finishing. Therefore, the kiln drying properties of lumber from such species as Persimmon, Oak, Ramin and Meranti which are used in large quantity for manufacturing exporting wood products have been studied. Also the real state of kiln drying industry in Korea was investigated. 3. Results and proposal for practical use of the research 3. 1 Results of the research 3.1.1 The end checks and the time for drying from intial moisture content of about 40 percent to 5 percent moisture content in ovendry were investigated as Table 1. 3.1.2 The kiln dried results, for 30mm stock, which are presented by using kiln schedule Table 2 are as Table 3. 3.1.3 The kiln schedule for Persimmon which has a normal drying properties is given in Table 4. However, the persimmon which has easy checking properties should be air dried under a relative humidity of above 85% until reaching about 25 percent moisture content. 3.1.4 The kiln schedules for ramin, meranti and oak are given respectively as follows. Ramin kiln schedule ............ Table 5 and Table 6 Meranti kiln schedule ............ Table 7 Oak kiln schedule ............ Table 8 3.2 Proposal for practical use of the research Firms using the above species should be informed the results of the research so they can be used to preventing drying defects and shortening drying time.

• Journal of the Korean Wood Science and Technology
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• v.43 no.4
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• pp.446-455
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• 2015

Based on comparative studies on standards and grading procedures of machine graded lumber in Korea and other countries, this study proposed a procedure of determining the grade classification and design strengths of domestic machine graded lumber. Differences between machine stress rated lumber and E-rated laminations were detailed in order to clarify the need for the procedure improvement. To this improvement the use of average MOE requirement for grading was introduced instead of the fixed minimum MOE requirement which is currently used in the Korean standards. It was found that the fixed minimum MOE requirement method was easier for an inspector to grade but, less efficient as a strength predictor than the average MOE requirement method. The advantage of average MOE requirement method is statistically MOR-MOE regression-based MOR prediction and highly efficient in quality control though it requires a computer-aided operation system in an initial setup. A major weakness of the current Korean grading system was found that different strength characteristics depending on wood species were not reflected on the grade classification and the tabulated allowable design stress. The proposed procedures were developed taking advantages of respective merits of both methods and based on MOR-MOE regression analysis. Through this procedure, the grades of machine stress rated lumber should be revised to become interchangeable with E-rated lamination, which would be beneficial to the cost competitiveness of domestic machine graded lumber and glued laminated timber industry.

• Korean Journal of Ecology and Environment
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• v.49 no.1
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• pp.11-21
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• 2016

Cymbidium kanran Makino is being threatened in its own habitats due illegal collecting and habitat changes by vegetation growth along historical landuse change. In this study, we established habitat restoration model for conservation of C. kanran based on ecological diagnosis. Through exploration to Jeju Island in 2014 and 2015, we identified 27 unknown habitats of C. kanran and in there, abiotic variables and vegetation structure and composition were quantified. Altitudinal distribution of C. kanran was between 200 m~700 m a.s.l. and compared to distribution in 2004, Area of Occupation (AOO) decreased at 82%. Specific habitat affinity was not observed by evenly found in mountain slope and valley and summergreen and evergreen broadleaved forests, but likely more abundant in valley habitats with higher soil and ambient moisture. Total of 96 individual of C. kanran was observed with an average density of $942.6individuals\;ha^{-1}$. The plants showed relatively short leaf length (average=$10.7cm{\pm}1.1cm$) and small number of pseudo bulbs ($1.2{\pm}0.2$). Flowering and fruiting individuals were not observed in field. C. kanran was classified into endangered plant species as CR (Critically Endangered) category by IUCN criteria. Phenotypic plasticity of C. kanran was likely support to sustain in more shaded habitat environment and recent habatat changes to closed canopy and low light availability may exhibit negatively effects to C. kanran's life history. Restoring C. kanran habitat should create open environment as grassland and low woody species density.

• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.3
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• pp.174-178
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• 1986

This experiment was carried out to study the influence of temperature treatments on germination of sorghum (cv. Pioneer 931), sorghum-sudangrass (cv. Pioneer 988), sudangrass (cv. Piper) and corn (cv. Suweon 19) in growth chamber. Each crop seeds were germinated under different day/night temperature of 10/5, 15/10, 20/15, 25/20, 30/25, 35/30 and $40/35^{\circ}C$ over 14/10 hour days. The results obtained are summarized as follows. 1. Germination of sorghum and sorghum-sudangrass were less affected by high temperature than those of corn and sudangrass. The optimum temperatures for germination were $20-40^{\circ}C$ for sorghum and $20-30^{\circ}C$ for corn. High temperature($40/35^{\circ}C$), however, resulted in great decrease of seed germination rates of seed germination rates of corn, while those of sorghum and sorghum-sudangrass shown high germination rates with the value of 95.8% and 89.9%, respectively. 2. Sorghum-sudangrass hybrid was shown to have a great tolerance to low temperature. Under low temperature($10/5^{\circ}C$) seed germination of sorghum-sudangrass was 80.0% but those of corn and sudangrass were 43.2% and 24.8% respectively. Germination rates of sorghum were decreased to about 68.8% at low temperature from a value of 98.1% at optimum temperature. 3. The days required to the seed germination of sorghum and sorghum-sudangrass hybrid were shortened by increasing of temperature. Under different temperature treatments, it was required 12 days ($15/10^{\circ}C$), 6 days ($25/20^{\circ}C$) and 3 days ($40/35^{\circ}C$) in sorghum but corn required 16, 7 and 3 days, respectively.

• Restorative Dentistry and Endodontics
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• v.18 no.2
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• pp.515-525
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• 1993

The purpose of this study was to evaluate the susceptibility of anaerobic microorganisms to certain antibiotics and root canal cements. Prevotella intermedia(Bacteroides intermedius) ATCC 25611(serotype A), Fusobacterium nucleatum ATCC 25586, Actinomyces viscosus ATCC 15987 which are the predominant pathogenic anaerobes in dental root canals were cultured in BHI for 48 hours(Fig.1). After each $200{\mu}l$ of those broths with microorganisms was streaked on each surface of blood agar plate, 2 to 5 antibiotic discs which are impregnated with Tetrncycline, Erythromycin, Ampicillin, Clindamycin, or Vancomycin were applied on each surface of blood agar plate and cultured for 5 days anaerobically in the anaerobic chamber (Fig.2). 15 antibiotic discs for each kind of antibiotics and each species of microorganisms were tested. Also each kind of root canal cement tubes which include Zinc oxide eugenol cement, Zinc phosphate cement, Calcium hydroxide powder+DD.W., Calcium hydroxide paste(Pulpdent Tempcanal), or Vitapex(Table 1) were applied on the inoculated BAPs after $200{\mu}l$ of each experimental species of microorganisms was streaked on the surface of blood agar plates, and they were cultured for 5 days anaerobically in the anaerobic chamber(Fig.3). The sensitivity(antimicrobial effect) was determined by the diameter of the inhibition zone. The results are as follows: 1. The results of antibiotic susceptibility test(Table 2) 1) All of the tested antibiotics had antimicrobial activity with various degrees. 2) In Prevotella intermedia (old Bacteroides intermedius), the diameter of inhibition zone to Erythromycin($37.87mm{\pm}2.20$) was largest, those to Tetracycline($26.20mm{\pm}2.96$), Vancomycin($21.53mm{\pm}1.96$), Clindamycin($18.73mm{\pm}0.96$) was smaller than former orderly, and That to Ampicillin ($7.87mm{\pm}0.83$) was smallest. 3) In Actinomyces viscosus, the diameter of inhibition zone to Erythromycin($28.73mm{\pm}1.22$) was largest, those to Ampicillin($21.73mm{\pm}1.03$), Clindamycin($21.33mm{\pm}1.59$) was similarly next order, that to Vancomycin($19.00mm{\pm}1.96$) was smaller than Clindamycin, and that to Tetracycline($11.93mm{\pm}0.70$) was smallest. 4) In Fusobacterium nucleatum, the diameter of inhibition zone to Ampicillin($31.07mm{\pm}1.91$) was largest, that to Erythromycin($28.87mm{\pm}0.92$), Clindamycin($20.47mm{\pm}1.51$), Vancomycin ($16.73mm{\pm}0.96$), Tetracycline ($12.13mm{\pm}1.06$) are smaller than former orderly. 2. The results of root canal cements and pastes(Table 3) 1) The external diameter of tube is 4mm, so 4mm of the inhibition zone diameter means non-susceptable. Prevotella intermedia (old Bacteroides intermedius) was non-susceptable to Calcium hydroxide powder+D.D.W., Calcium hydroxide paste(pulpdent Tempcanal), and Actinomyces viscosus was non-susceptable to Zinc phosphate cement, Calcium hydroxide powder + D.D.W., Calcium hydroxide paste(pulpdent Tempcanal). 2) In Prevotella intermedia (old Bacteroides intermedius), the diameter of inhibition zone to Zinc oxide eugenol cement($13.67mm{\pm}3.30$) was largest, that to Vitapex($9.20mm{\pm}2.96$), Zinc phosphate cement($6.13mm{\pm}2.07$) was smaller than former. 3) In Actinomyces viscosus, the diameter of inhibition zone to Zinc oxide eugenol cement($17.40mm{\pm}5.20$) was largest and that to Vitapex($8.80mm{\pm}1.70$) was next order. 4) In Fusobacterium nucleatum, the diameter of inhibition zone to Vitapex($42.33mm{\pm}17.2$) was largest and those to Calcium hydroxide paste(Pulpdent Tempcanal)($14.47mm{\pm}3.72$) and Zinc oxide eugenol cement($8.93mm{\pm}2.71$), Zinc phosphate cement($8.20mm{\pm}2.27$), Calcium hydroxide powder+D.D.W.($5.53mm{\pm}2.10$)was next orderly. And then In Zinc oxide eugenol cement and Zinc phosphate cement group, two of fifteen samples showed no inhibition zone, in Calcium hydroxide powder + D.D.W. group, 8 of 15 samples showed no inhibition zone.

• Journal of The Korean Society of Grassland and Forage Science
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• v.28 no.2
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• pp.119-128
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• 2008

The object of this experiment was to investigate the food habits of Korean native goats fed with various roughage sources. The feeding trials were conducted at Chungnam National University and Unbong Animal Genetic Resources Station in 2007. The experimental roughages sources were five including 25 species in all; grass sources: 5 species (Lolium perenne, Festuca arundinacea, Poa pratensis, Agrostis alba and mixed grass, legume sources: 5 species (Trifolium pratense, Medicago sativa, Trifolium repens, Melilotus officinalis and Vicia villosa), browse sources: 5 species(Quercus serrata Thunb., Prunus jamasakura Sieb., Quercus aliena Blume, Robinia pseudoaccacia and Pinus densiflora), weed sources: 5 species(Artemisia princeps Pampanini, Erigeron canadensis, Alopecurus aegualis Sobolewski, Echinochloa crusgalli var. frumentacea (Roxb.) Wight and Rumex crispus), and native grass sources: 5 species(Zoysia japonica Steudel, Agropyron tsukushiense var. transiens(Hack) Ohwi., Arundinella hirta(Thunb.) Tanaka, Miscanthus sinensis Anderss and Phragmites comunis Trin). Ten Korean native goats were selected which had nearly the same body weight(average 30.6kg, 남) as experimental animals. Experimental roughages were prepared by 0.5kg per 1 species fed to Korean native goats, and the experiment was carried out from 08:00 to 20:00. The chemical composition and dry matter digestibility of each roughage source and species were significantly different at the sampling area, plant species, growth stages and cutting period (p<0.05). The Korean native goats ate more roughages which had low fibrous contents, but high dry matter digestibility. Among all the 25 species of roughages, the favorite intake species order by Korean native goats was observed like this: Quercus serrata Thunb., Quercus aliena Blume, Trifolium repens, and Pinus densiflora and Artemisia princeps Pampanini which was lower intake compared to other domestic herbivores. On the other hand, compared to each roughage source, total intake amount by Korean native goats was showed as browse(29.9%), legumes(23.0%), weeds(21.6%), grasses(21.5%) and native grasses(4.0%), respectively. Based on the result, the food habit of Korean native goats seems to be closer to browser type.

• Restorative Dentistry and Endodontics
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• v.14 no.2
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• pp.20-29
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• 1989

The purpose of the study is to evaluate the degree of the marginal leakage of class V cavities with 4 brands of esthetic filling materials by means of the dye penetration at the enamel & dentinal margins. 160 cavities of class V were prepared on the buccal & lingual surfaces of 80 extracted premolar teeth, which divided into 4 groups. The four groups of cavities were filled with Durafill$^{(R)}$-Durafill bond$^{(R)}$(KuIzer & Co GmbH), Bisfil M$^{(R)}$-Resin bond$^{(R)}$(BISCO Inc.), Silux$^{(R)}$-Scotchbond$^{(R)}$(3M Co.) and Fuji ionomer$^{(R)}$(type II, G-C Co.) each. All specimens were immersed in 2% methylene blue dye solution for 24 hours at $37^{\circ}C$ after a 30-second thermocycling at $4^{\circ}C$ and $60^{\circ}C$ and longitudinally sectioned with diamond disk into two parts. The results were as follows : 1. At enamel margins, the group filled with Durafill$^{(R)}$-Durafill bond$^{(R)}$, Bisfil M$^{(R)}$-Resin bond$^{(R)}$ and Silux$^{(R)}$-Scotchbond$^{(R)}$ show no significant difference each other(p>0.05), and the above groups show less marginal leakage comparing with the group filled with Fuji ionomer$^{(R)}$(p<0.01). 2. At dentinal margins, the group filled with Silux$^{(R)}$-Scotchbond$^{(R)}$ or Fuji ionomer$^{(R)}$ show less marginal leakage than that with Durafill$^{(R)}$-Durafill bond$^{(R)}$ or Bisfil M$^{(R)}$-Resin bond$^{(R)}$(p<0.01). 3. The enamel margins show less marginal leakage than dentinal margins in all the class V cavities(p<0.01).

• Journal of Periodontal and Implant Science
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• v.32 no.4
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• pp.781-800
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• 2002

The major goals of periodontal therapy are the functional regeneration of periodontal supporting structures already destructed by periodontal disease. There have been many efforts to develop materials and therapeutic methods to promote periodontal wound healing. With the development of non-resorbable membrane, GTR has proved to be the representive technique of periodontal regeneration. However, due to various clinical problems of non-resorbable membrane, resorbable membrane was developed and it showed to be clinically effective. The newly developed Para-Dioxanone membrane has a characteristic of non-woven fabric structures which is different from the generally used membranes with structure of mesh form. In addition, Chitosan membrane has been developed to apply its adventage maximally in GTR. Although a number of different types of membranes had been clinically used, researches on absorption rate of membranes were inadequate and limited to subjective opinions. However, since long term period of resorption and space maintenance are required in implant or ridge augmentation, accurate verification of resorption rate is clinically important. In this study, we had implanted Resolut(R), Biomesh(R), Para-Dioxanone membrane and Chitosan membrane (Size : 4mm ${\times}$ 4mm) on dorsal side of Sprague Dawley rat, and sacrified them after 4 weeks, 8 weeks, 12 weeks respectively. Histologic observation was carried out, and the following results were obtained by calculating the objective resorption rate. 1. In case of Resolut(R), external resorption took place initially, followed by internal resorption. Surface area are 5.76${\pm}$2.37$mm^2$, 4.90${\pm}$l.06$mm^2$, 4.90${\pm}$0.98$mm^2$ at 4 weeks, 8 weeks, 12 weeks respectively, and invasion rate of connective tissue to membrane are 31.6${\pm}$4.5%, 52.8${\pm}$9.4%, 56.4${\pm}$5.1% respectively. 2. Biomesh(R) showed a pattern of folding, relatively slow resorption rate with small size of membrane. Surface area are 3.62${\pm}$0.82$mm^2$, 3.63${\pm}$0.76$mm^2$, 4.07${\pm}$1.14$mm^2$ at 4 weeks, 8 weeks, 12 weeks respectively, and invasion rate of connective tissue to membrane are 26.1${\pm}$5.8%, 30.9${\pm}$3.4%, 29.2${\pm}$3.6%, respectively. 3. Para-Dioxanone membrane was surrounded by fibrous conncetive tissue externally, and resorption took place internally and externally. Surface area are 5.96${\pm}$1.05$mm^2$, 4.77${\pm}$10.76$mm^2$, 3.86${\pm}$0.84$mm^2$ at 4 weeks, 8 weeks, 12 weeks respectively, and invasion rate of connective tissue to membrane are 30.7${\pm}$5.1%, 53.3${\pm}$4.4%, 69.5${\pm}$3.1%, respectively. 4. Each fiber of Chitosan membrane was surrounded by connective tissue and showed external resorption pattern. It showed little invasion of inflammatory cells and excellent biocompatability. The resorption rate was relatively slow. Surface area are 6.01${\pm}$2.01$mm^2$, 5.49${\pm}$1.3$mm^2$, 5.06${\pm}$1.38$mm^2$ at 4 weeks, 8 weeks, 12 weeks respectively, and invasion rate of connective tissue to membrane are 31.3${\pm}$3.6%, 38.4${\pm}$3.80%, 39.7${\pm}$5.6%, respectively. Consequently, Para-Dioxanone membrane and Chitosan membrane are found to be clinically effective for their excellent tissue reaction and biocompatibility. Futhermore, the advantage of bone regenerating ability as well as the relatively long resorption period of Chitosan membrane, it might be widely used in implant or ridge augmentation.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.4
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• pp.318-324
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• 2015

Purpose: This study compared shear bond strengths of five self-adhesive cements with phosphate monomer to zirconium oxide ceramic with and without airborn particle abrasion. Materials and methods: One hundred zirconia samples were air-abraded ($50{\mu}mAl_2O_3$). One hundred composite resin cylinders were fabricated. Composite cylinders were bonded to the zirconia samples with either Permacem 2.0 (P), $Clearfil^{TM}$ SA Luting (C), $Multilink^{(R)}$ Speed (M), $RelyX^{TM}$ U200 Automix (R), G-Cem $LinkAce^{TM}$ (G). All bonded specimens were stored in distilled water ($37^{\circ}C$) for 24 h and half of them were additionally aged by thermocycling ($5^{\circ}C$, $55^{\circ}C$, 5,000 times). The bonded specimens were loaded in shear force until fracture (1 mm/min) by using Universal Testing Machine (Model 4201, Instron Co, Canton, MA, USA). The failure sites were inspected under field-emission scanning electron microscopy. The data was analyzed with ANOVA, Tukey HSD post-hoc test and paired samples t-test ($\alpha$=.05). Results: Before and after thermocycling, $Multilink^{(R)}$ Speed (M) revealed higher shear-bond strength than the other cements. G-Cem $LinkAce^{TM}$ (G) showed significantly lower bond strengths after thermocycling than before treatment (P<.05), but the other groups were not significantly different (P>.05). Conclusion: Most self-adhesive cements with phosphate monomer showed high shear bond strength with zirconia ceramic and weren't influenced by thermocycling, so they seem to valuable to zirconia ceramic bonding.