• Journal of Korean Society of Forest Science
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• v.78 no.2
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• pp.177-188
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• 1989

The habitat typing method of classification based on community has been developed on many forested areas in the ROCKY MOUNTAINS of WESTERN NORTH AMERICA, and is being used in providing an objective principle of guide for classification of forest sites, land classification, vertical distribution and multipurpose management of forest. I actually made a trial of forest habitat type classification - The methodology can be segmented into a number of tasks including reconnaissance, selection of stands to be sampled, location of plots, data gathering, preliminary and computer analysis, preparation of key- and map of habitat type and description for each habitat type in a view of forest management - on UNIVERSITY OF MONTANA FORESTS in order to examine whether its application is fit or not in korean forest circumstances : these are composed mainly of artificial forest and forest in the early stage of succession. The main results obtained from this study were summarized as follows 1. A hierarchical classification-Climax, Habitat type and Phases-of forest sites was developed using the habitat typing method of classification. 2. A diagnostic key is provided for field identification of the types based upon presence and number of indicator species, and forest managers could prepare a map of habitat type and classify forest habirat types by reference to it. 3. The classified habitat types were considered to be effective on providing an objective principle of guide for multipurpose management of forest including potential productivity for timber, feed productivity of forage and wildlife, selection of the right species in the right sites, application of method of treatment and so forth. 4. Forest habitat type classifications based upon extrapolation which used relict species and associated stands is considered to be suitable for korean forest circumstances and objective in studying potential vegetation, vertical and horizontal distribution of forest.

• Journal of Korean Society of Forest Science
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• v.7 no.1
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• pp.3-7
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• 1968

The Capacity of wood to absorb water is very important as the basis data for wood industry, particularly in preservatives impregnation, manufacturing of improved wood, selection of packing boards, etc. In this study differences in Water absorbing Capacity of wood by structual section, water soaking time were investigated. (1) The species used in this investigation were Larix olgensis Henry Var. Koreana Nakai and Juglans mandshurica Max., and dimension of these testing wood block was $30{\times}30{\times}100cm$; and these were soaked in fresh water of $25{\pm}1^{\circ}C$ for 8.5day and 0.5 day, before measurement. (2) The result showed that the water absorption by cross sections was greater than by either radial or tangential section and there were no differences between radial and tangential section. (3) The water absorption of Juglans mandshurica Max. which has the relatively low specific gravity was greater than Larix olgensis Henry Var. Koreana Nakai which has generally high specific gravity. (4) The result showed an increase in the absorbed water with increase in the length of soaking time. However the water absorption rate during the early period of soaking was very high and thereafter the rate decreased with passage of time. More than a half of the total water absorption was achieved during the first 2 days approximately. (5) The relationships between the length of the soaking-time and water absorption were found to be as follows : Larix olgensis Henry Var. Koreana Nakai Cross section : $y=111.1{\times}^{0.6516}$ radial section : $y=32.2{\times}^{0.5146}$ tangential section : $y=36.5{\times}^{0.5112}$ Juglans mandshurica Max. Cross section : $y=216.1{\times}^{0.5914}$ radial section : $y=27.9{\times}^{0.5832}$ tangential section : $y=50.9{\times}^{0.4769}$ Where : y is amount of water absorption ($mg/cm^2$) x is water-soaking time (days).

• Journal of dental hygiene science
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• v.12 no.6
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• pp.607-616
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• 2012

The purpose of this study was to examine the self-rated oral health status and oral health concern of 6,094 adults over the age of 19, which were both related to subjective oral health awareness, based on the second-year (2008) raw data of the 4th National Health and Nutrition Survey. 1. As for subjective oral health awareness, 49.4 percent replied they were in bad oral health when they were asked about self-rated oral health status. Regarding oral health concern, 62.6 percent answered they were sort of concerned about oral health. 2. As to oral health indexes by sociodemographic characteristics, there were statistically significant differences in oral health indexes according to gender, age, academic credential, monthly mean household income, frequency of eating between meals and toothbrushing frequency. Smoking made no statistically significant differences to oral health indexes (p<0.000). 3. Concerning self-rated oral health status by sociodemographic characteristics, no significant differences were found according to gender, age and academic credential, and there were statistically significant differences according to monthly mean household income and smoking (p<0.000), frequency of eating between meals (p<0.018), toothbrushing frequency (p<0.003). 4. In relation to oral health concern by sociodemographic characteristics, gender and smoking made no significant differences, and statistically significant differences were found according to age (p<0.003), academic credential, monthly mean household income, frequency of eating between meals and toothbrushing frequency (p<0.000). 5. In regard to the relationship between subjective oral health awareness and oral health indexes, none of the oral health indexes had a significant relationship to self-rated oral health status, and there were statistically significant differences in oral health concern according to functioning teeth index (p<0.011) and community periodontal index (p<0.017).

• Journal of dental hygiene science
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• v.12 no.6
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• pp.644-651
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• 2012

This study purports to measure the level of work friendship in dental clinic and examines the friendship's effect on the organizational effectiveness. Data were collected from workers who worked in dental clinic located in Seoul and Gyeonggi areas by self-administered questionnaires from early in October till lately in September, 2009 through direct interview and e-mail. Among 250 questionnaires, 240 responses were returned, and 17 copies with an inaccurate answer were excluded. Finally 223 responses were analyzed through SPSS program. The study revealed that the work friendship in dental clinic has enormous influence on job satisfaction, occupational commitment, intent to leave, stress etc. The results imply that the managers of the dental clinics need to create an organizational climate which emphasizes on a good relationship among members and have them take part in various committees or informal activities.

• Journal of dental hygiene science
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• v.9 no.2
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• pp.169-179
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• 2009

This study aims to present a fundamental data base to figure out the mental and the physical conditions that the dental technicians are facing and ultimately to develop a health care program to deal with their health related problems. To this end, we took an analysis on the health status among the subjects of 895 dental technicians currently working at the dental lab around the nation from January 15 to March 31, 2009 by way or Todai Health Index(THI). Of the average scale point in accordance with 12 scale scores of the physical and the mental subjective symptom, the results revealed that the physical appeals (21.10) were higher than the mental appeals (18.49) and the multiple subjective symptom was marked as 38.44 followed by the mental irritability (25.92). In gender differences, the females proved to be higher than the males in both physical appeals and mental appeals while the physical appeals were dominant in both genders. The physical appeals were higher than the mental appeals with regard to the general characteristics. In the case or the group or age twenties as shown in the physical and mental average scale point, the other groups showed 21.55% of the physical appeals among the married whereas the mental appeals showed the highest point as 18.70 in the unmarried group. In job position, the other groups marked the highest, in working condition, below average group marked the highest, in frequency of break time, none group marked the highest. We drew a conclusion form this study that the dental technicians gained the higher points in the item or the multiple subjective symptom, the menial irritability, and the irregular life. More research on th is phenomena should be followed along with the development of various and practical health care programs to promote the health or dental technicians.

• Korean Journal of Dental Materials
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• v.44 no.2
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• pp.171-178
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• 2017

The purpose of this study is to investigate the effect of number of times dipped in coloring liquid and sintering temperature on the flexural strength of zirconia ceramic. In this study, using a zirconia block having improved transparency, specimens with size of $25mm{\times}2mm{\times}1.5mm$ were fabricated. The zirconia ceramic specimens were divided into three groups according to the number of times dipped in coloring liquid by 0, 2 and 4 times, and dyed in the coloring liquid to give color to each specimen. Then, after sintering them at the final temperature of $1,450^{\circ}C$ and $1,600^{\circ}C$, flexural strength was measured using a universal testing machine (total 6 group, n=10 for each group). Also, a scanning electron microscopy (SEM) was performed to observe its microstructure, and the data obtained through the experiment were analyzed with two-way ANOVA. The results of the flexural strength analysis show that the highest value was measured $762.3{\pm}42.3MPa$ in EKL2 group, while the lowest value was $516.4{\pm}77.1MPa$ in EKH4 group. According to the results of the two-way ANOVAs, flexural strength was not related with interaction between sintering temperature and number of times dipped in coloring liquid ($R^2=0.737$). However, there were statistically significant differences in flexural strength depending on sintering temperature (P<0.001). The flexural strength of zirconia ceramics having improved transparency was dependent on sintering temperature. The number of times dipped in the coloring liquid did not affect flexural strength of the zirconia ceramic having improved transparency.

• Korean Journal of Dental Materials
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• v.44 no.3
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• pp.273-280
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• 2017

The aim of the present study was to investigate the effects of specimen dimension on the flexural properties and testing reliability of dental composite resin. The composite resin was prepared experimentally by mixing a resin matrix with silanated micrometer glass filler at 50 vol%. Flexural specimens with various dimension in specimen's width were fabricated by light curing using a split metal mold; $25{\times}2{\times}2mm$, $25{\times}2{\times}4mm$, $25{\times}2{\times}6mm$ in length ${\times}$ height ${\times}$ width. The flexural strength and modulus were determined according to ISO 4049 test protocol at a span length of 20 mm (normal-flexural strength; NFS). Another flexural test was conducted using mini-sized specimens ($12{\times}2{\times}2mm$, $12{\times}2{\times}4mm$, $12{\times}2{\times}6mm$) from the broken specimens at a span length of 10 mm (mini-flexural strength; MFS). Data were analyzed with ANOVA and Duncan's post-hoc test and the test reliability was evaluated by Weibull analysis. Results showed that there are generally no significant difference in flexural strength with the increase in the specimen width in NFS and MFS tests. However, the test reliability of flexural strength based on Weibull analysis was largely changed with the variables in the dimension of width and span length. The flexural modulus of NFS was increased as the dimension of specimens width increased while there was no trend in flexural modulus of MFS test. Overall results recommend that the evaluation of flexural properties and the reliability of dental composite resins should be performed with more than one test method.

• Journal of agriculture & life science
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• v.46 no.5
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• pp.73-82
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• 2012

Allele information from the analysis of the 13 microsatellite (MS) markers, were classified into the $F_0$, $F_1$ and $F_2$ generations, and probabilities of the same individual emergency in each generation was calculated. As a result, the 13 MS markers showed an estimate of $3.84{\times}10^{-23}$ on the premise of the randomly mated group of $F_2$, which implies that the same individuals may emerge by the use of 37 kinds of SNP markers. In this study, the experimental pigs were intercross between only 2 breeds (Korean native pig and Landrace). In addition, the success rate of paternity tests was analyzed on the whole group, by the use of the 13 MS markers and 37 SNP markers. As regards the exclusionary power of the second parent ($PE_{pu}$), MS markers and SNP markers showed 0.97897 and 0.99149, respectively. In relation to the parent exclusion power of both parent (PE), MS markers and SNP markers showed 0.99916 and 0.99949, respectively. In the case of the estimate to identify parental candidates that had the highest probability ($PNE_{pp}$), the two showed 1.00000 all. The Korean pig industry tends to mass produce hogs with limited numbers of alleles in limited parents. Such being the case, there is a need to organize a marker, for which it is imperative to find markers with high efficiency and high economic feasibility of the characteristics of DNA markers, sample size, the accuracy and expenses of genotyping cost, the manageability of data and the compatibility among analysis systems.

• Journal of agriculture & life science
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• v.44 no.6
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• pp.83-89
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• 2010

The objective of this study was to investigate the effect of the environmental and genetic factors on the carcass traits of Korean cattle. We have used the data of 22,954 Korean cattle slaughtered from 2005 to 2009 in Gyeongnam region and estimated the genetic parameters of 36,868 cattle including the pedigree individuals by means of EM-REML analytical method. In summary, the heritability of the carcass weight, eye muscle area, backfat thickness and marbling score was 0.39, 0.30, 0.33 and 0.62, respectively. The carcass weight and the eye muscle area showed high correlation between them with the genetic correlation of 0.86 and the phenotypic correlation of 0.72. The high heritability of marbling score is assumed to be the result of focusing the breed improvement on the quality of the meat. Through this study, it is considered that the Korean cattle in Gyeongnam region are improving, which will thus contribute to the increase of the farmer's income. Additional study on the economic trait must be carried out to obtain clearer results that will lead to further improvement of Korean cattle.

• Journal of agriculture & life science
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• v.44 no.2
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• pp.7-15
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• 2010

This study was conducted to investigate the bacteriological and physiological quality of seawater and surface sediments in Sacheon Bay of Korea from January to September in 2009. During the study period, the means of temperature was range from 5.3 to $24.9^{\circ}C$ (mean $17.7{\pm}0.4^{\circ}C$), transparency range from 1.4 to 2.5 m (mean $1.8{\pm}0.5m$), suspended solid ranged from 16.2 to 35.8 mg/L (mean $24.2{\pm}2.2mg/L$), chemical oxygen demand ranged from 1.42 to $3.29mgO_2/L$ (mean $2.06{\pm}0.55mgO_2/L$), dissolved oxygen ranged from 6.7 to 9.5mg/L (mean $7.9{\pm}0.6mg/L$), respectively. Seafood, if eaten raw, carries the risk of food poisoning. Seafood poisoning is often cause by pathogenic microorganism originating from fecal contamination, such as Salmonella sp., Shigella sp. and norovirus. Fecal coliforms are an important indicator of fecal contamination. Therefor, data on fecal coliform are very important for evaluating the safety of fisheries in coastal areas. So, we investigated the sanitary indicate bacteria. In this study, 56 sea water samples were collected from the Sacheon Bay, and total and fecal coliforms were compared and analyzed. The coliform group and fecal coliform MPN's of sea water in Sacehon Bay were ranged from <1.8~7,900 MPN/100mL (GM 214.7 MPN/100mL) and <1.8~330 MPN/100mL (GM 9.7 MPN/ 100mL), respectively. Total coliforms were detected in 75.0% of the samples and 76.2% of the total coliforms were fecal coliforms. During the study period, the means of water content, ignition loss, COD, and acid volatile sulfates in sediments in Sacheon Bay were $53.28{\pm}2.58%$, $9.38{\pm}0.42%$, $14.23{\pm}3.36mgO_2/g$, $0.09{\pm}0.07mgS/g$, respectively.