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Effect of infection control barrier thickness on light curing units (감염 조절용 차단막의 두께가 광중합기의 중합광에 미치는 영향)

  • Chang, Hoon-Sang;Lee, Seok-Ryun;Hong, Sung-Ok;Ryu, Hyun-Wook;Song, Chang-Kyu;Min, Kyung-San
    • Restorative Dentistry and Endodontics
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    • v.35 no.5
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    • pp.368-373
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    • 2010
  • Objectives: This study investigated the effect of infection control barrier thickness on power density, wavelength, and light diffusion of light curing units. Materials and Methods: Infection control barrier (Cleanwrap) in one-fold, two-fold, four-fold, and eightfold, and a halogen light curing unit (Optilux 360) and a light emitting diode (LED) light curing unit (Elipar FreeLight 2) were used in this study. Power density of light curing units with infection control barriers covering the fiberoptic bundle was measured with a hand held dental radiometer (Cure Rite). Wavelength of light curing units fixed on a custom made optical breadboard was measured with a portable spectroradiometer (CS-1000). Light diffusion of light curing units was photographed with DSLR (Nikon D70s) as above. Results: Power density decreased significantly as the layer thickness of the infection control barrier increased, except the one-fold and two-fold in halogen light curing unit. Especially, when the barrier was four-fold and more in the halogen light curing unit, the decrease of power density was more prominent. The wavelength of light curing units was not affected by the barriers and almost no change was detected in the peak wavelength. Light diffusion of LED light curing unit was not affected by barriers, however, halogen light curing unit showed decrease in light diffusion angle when the barrier was four-fold and statistically different decrease when the barrier was eight-fold (p < 0.05). Conclusions: It could be assumed that the infection control barriers should be used as two-fold rather than one-fold to prevent tearing of the barriers and subsequent cross contamination between the patients.

Studies on the Time Distribution of Heavy Storms (暴雨의 時間的 分布에 關한 硏究)

  • Lee, Keun-Hoo
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.26 no.2
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    • pp.69-84
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    • 1984
  • This study was carried out to investigate the time distribution of single storms and to establish the model of storm patterns in korea. Rainfall recording charts collected from 42 metheorological stations covering the Korean peninsula were analyzed. A single storm was defined as a rain period seperated from preceding and succeeding rainfall by 6 hours and more. Among the defined single storms, 1199 storms exceeding total rainfall of 80 mm were qualified for the study. Storm patterns were cklassified by quartile classification method and the relationship between cummulative percent of rainfalls and cummulative storm time was established for each quartile storm group. Time distribution models for each stations were prepared through the various analytical and inferential procedures. Obtained results are summarized as follows: 1. The percentile frequency of quartile storms for the first to the fourth quartile were 22.0%, 26.5%, 28.9% and 22.6%, respectively. The large variation of percentile frequency was show between the same quartile storms. The advanced type storm pattern was predominant in the west coastal type storm patterns predominantly when compared to the single storms with small total rainfalls. 3. The single storms with long storm durations tended to show delayed type storm patterns predominantly when compared to the single storms with short storm durations. 4. The percentile time distribution of quartile storms for 42 rin gaging stations was estimated. Large variations were observed between the percentiles of time distributions of different stations. 5. No significant differences were generally found between the time distribution of rainfalls with greater total rainfall and with less total rainfall. This fact suggests that the size of the total rainfall of single storms was not the main factor affecting the time distribution of heavy storms. 6. Also, no significant difference were found between the time distribution of rainfalls with long duration and with short duration. The fact indicates that the storm duration was no the main factor affecting the time distribution of heavy storms. 7. In Korea, among all single storms, 39.0% show 80 to 100mm of total rainfall which stands for the mode of the frequency distribution of total rainfalls. The median value of rainfalls for all single storms from the 42 stations was 108mm. The shape of the frequency distribution of total rainfalls showed right skewed features. No significant differences were shown in the shape of distribution histograms for total rainfall of quartile storms. The mode of rainfalls for the advanced type quartile storms was 80~100mm and their frequencies were 39~43% for respective quartiles. For the delayed type quartile storms, the mode was 80~100mm and their frequencies were 36!38%. 8. In Korea, 29% of all single storms show 720 to 1080 minutes of storm durations which was the highest frequency in the frequency distribution of storm durations. The median of the storm duration for all single storms form 42 stations was 1026 minutes. The shape of the frequency distribution was right skewed feature. For the advanced type storms, the higher frequency of occurrence was shown by the single storms with short durations, whereas for the delayed type quartile storms, the higher frequency was shown gy the long duration single storms. 9. The total rainfall of single storms was positively correlated to storm durations in all the stations throughout the nation. This fact was also true for most of the quartile storms. 10. The third order polynomial regression models were established for estimating the time distribution of quartile storms at different stations. The model test by relative error method resulted good agreements between estimated and observed values with the relative error of less than 0.10 in average.

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A Study on Growth Condition and Management of Protected Trees in Kimpo (김포시 보호수의 생육실태와 관리방안 연구)

  • Doo, Chul-Eon;Lee, Jong-Bum;Lee, Jae-Keun
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.30 no.1
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    • pp.125-134
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    • 2012
  • This study is determined by tree vigor of analyzing of each object's growth condition in Locational Characteristics and compare the result with impediment extent rate in crown area to provide the management Study about the influence of man-made structures in numbers of protected trees. 68 places where are in the list of Kimpo protected trees were researched in Natural environments, vital degree of trees, number of trees. Crown area was calculated surveying it around the directions of North, East, South and West branching out. Impediment in the area was analyzed after classified into artificial impediment like paved surface(ascon, concrete, block, etc.), a building and a breast wall and natural impediment like soil, stonework and gravel and conclusions are as follow. In analyzing of natural environments, he ground where protected trees have located is consist of 72.05 of manmade structure and artificial in all. There are many protected trees which have less space than crown area for growth suggested by Woo-kyung Sim and Se-kyun Shin in 1992. And it was analyzed that making growth space for protected trees and management of impediment are urgently needed because of that the proportion of impediment covering the crown area has increased as cities are becoming more urbanized results in transforming of trees and weakness of tree vigor. This research shows that under 20% of in crown area is tree vigor determination 1-2 grade 21-50% under is 2-3 grade, higher than 50% is 3-5 grade. More impediment have more difficulty for growing, with the management of root system of protected trees need to be under 20% of rate of land is necessary was improved. As follows are suggested about the standard of management in artificial impediment which influence the number of trees. Firstly, impediment in crown area must be restricted under 20%, but in case outside of the area is not artificial the rate could be higher considerable. Secondly, protected trees growth space secured as much as crown area and impediment must be installed outside the crown area. Thirdly, to move the protected trees, condition of growth space secure must be considered. Fourthly, to develope land, the area around protected trees should be utilized in a park, the area of impediment installation in crown area should be limited as well. Fifthly, As many shown in previous research, for the improvement of old big trees and protected trees, need the tax favor of landowner and purchase of around land, to manage, it needs the budget of local government and advice of expert. Also the study on how various kind of impediment nearby protected trees influence on them has to be continued.

A Seroepidemiological Study on Hepatitis B Vaccination Program - In Elementary School Student from Kyonggi-Do Province - (B형 간염 예방 접종 실태 평가를 위한 혈청 역학적 연구 -경기도 지역 초등학생을 대상으로-)

  • Lee, Suk-Yong;Choi, Boyoul;Shin, Young-Jeon;Bang, Keum-Nie;Ki, Moran;Park, Hung-Bae;Yoon, Jae-Deuk;Lee, Kye-Chol;Youn, Bae-Joong
    • Pediatric Infection and Vaccine
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    • v.4 no.2
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    • pp.240-256
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    • 1997
  • Purpose: To evaluate the hepatitis B vaccination program which has been conducted since 1980, Korea. Methods: This study was carry out self reported questionnaire and serologic test covering 2,072 elementary school students who were born between 1980 and 1987, selected by cluster sampling. The HBV serologic markers (HBsAg, Anti-HBs and Anti-HBc) were tested by radioimmunoassay (RIA). The contents of questionnaire include demographic data of students and parents, vaccination status, vaccination frequency, vaccination age, past history of mother's HBV test. Results: 1) The HBsAg positive rates by sex showed 3.7% for male and 2.7% for female, representing an average rate of 3.4%. The HBsAg positive rates by age group showed 5.6% for 13 years and l.5% for 6 years, representing a tendency of lowering rate as ages being younger. 2) The pre-natal HBV test rate was 10.2%, while post-natal HBV test rate was 42.5%. The test showed that the parents' educational level being higher than others, the pre- and post-natal HBV test showed higher rates. In case the fathers occupation being office worker, the post-natal HBV test showed a higher rate compared with other occupation. 3) Overall vaccination rate was 82.6%, complete vaccination rate 69.8%, booster injection rate 42.8%. The vaccination rate, complete vaccination rate and booster injection rate increased as the age being younger. If the educational level of parents were higher, the vaccination rate, complete vaccination rate and booster injection rate showed higher rates. Younger students showed younger vaccination age, and higher educational background of family showed younger vaccination ages. 4. With regard to positive rate of HBV markers by vaccination age, HBsAg and Anti-HBc positive rate showed higher degrees in the following order; preschool age (1-6 years), school age (6-13 years) and infancy (0-1 year). Anti-HBs positive rate was increased as the frequency of vaccination increased. Five years after initial complete vaccination, minimum protective rate was lowest, 69.6%.

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Evaluation of Early Productivity of High Density 'Fuji' Apple Orchards by Planting Well-feathered Trees/M.9 EMLA ('후지' 사과의 우량 측지묘/M.9 EMLA를 이용한 밀식재배원의 조기 생산성 평가)

  • Yang, Sang-Jin;Park, Moo-Yong;Song, Yang-Yik;SaGong, Dong-Hoon;Yoon, Tae-Myung
    • Horticultural Science & Technology
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    • v.28 no.3
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    • pp.374-380
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    • 2010
  • Well-feathered (5.2 feathers, stem diameter 13 mm) trees of 'Fuji' apple/ M.9 EMLA were planted at $4.0{\tiems}1.5$ m and whip trees (stem diameter 10 mm) of 'Fuji'/M.26 at $4.0{\times}2.0$ m were trained to the slender spindle. The productivity and yield efficiency of two orchard systems were compared for 6 years. The canopy volume of the tree/M.9 EMLA reached $2.07m^3$ in 2nd year and increased slowly to almost the targeted tree volume of $2.9m^3$ in 4th year. Trees/M.26 grew slowly at the begin but from 3rd year the tree volume expanded quickly to reach $5.6m^3$ in 5th year, covering over the allowed space. Yield of M.9 EMLA per 10a increased from 0.3 ton in 2nd year to 4.6 ton in 5th year, and 5.0 ton in 6th year, but yield of M.26 per 10a increased from 0.5 ton in 3rd to 2.9 ton in 6th year. Cumulative yield per 10a up to 6th year was 13.9 ton for M.9 EMLA but only 9.8 ton for M.26. Fruit weight for M.9 EMLA was heavier than that for M.26. In conclusion, the high density planting system with well-feathered trees/M.9 EMLA was better than the conventional wide planting system with whip trees/M.26.

Public Attitudes Toward Dying with Dignity and Hospice.Palliative Care (품위 있는 죽음과 호스피스.완화의료에 대한 일반 국민들의 태도)

  • Yun, Young-Ho;Rhee, Young-Sun;Nm, So-Young;Chae, Yu-Mie;Heo, Dae-Seuk;Lee, So-Woo;Hong, Young-Seon;Kim, Si-Young;Lee, Kyung-Sik
    • Journal of Hospice and Palliative Care
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    • v.7 no.1
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    • pp.17-28
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    • 2004
  • Purpose: Even though there have been various efforts for the dying with dignity of terminal patients, no researches focused on the public attitudes. Methods: In February 2004, we sampled 1,055 persons over 20 years of age from the sixteen cities and local districts of Korea through the quota sampling method according to their gender, age, and location. We conducted a telephone survey with a structured questionnaire on the attitudes toward dying with dignity and hospice palliative care. Results: The most important conditions for the dying with dignity on the patients' views were 'removing burdens for other people' (27.8%). Over the half of the samples chose their home as a preference for place of death (54.8%). 82.3% of the respondents agreed to the idea of withdrawing the medically futile life-sustaining treatment. Fifty seven percents of the answered public said that they intended to use the hospice service in case of terminal illness. Eighty percents thought that health care insurance should cover hospice service, and 80.9% gave positive response to the necessity of advance directives. Respondents emphasized 'the financial support for the terminal patients' (29.8%), 'covering hospice service with health insurance' (16.5%), and 'the education and public relation for settlement of desirable dying culture and hospice service' (15.9%) as the roles and responsibilities of the government for the dying with dignity. Conclusion: This study shows that there is a possibility of significant consensus on hospice and palliative care system for the dying with dignity of patients and reduction of the suffering for their families among the general public.

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A Study on the Present Conditions of Conservation & Management of the Natural Monuments of Korea (국내(國內)의 천연기념물(天然記念物) 보존(保存) 관리(管理) 실태(實態))

  • Na, Moung-Ha;Lee, Jin-Hee;Lee, Jae-Keun
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.28 no.2
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    • pp.127-136
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    • 2010
  • This study is aimed at reviewed and analyzed in order to suggest the improved plans related to natural monuments. The summary of this study is as followings; First, Replacing the current term 'cultural properties', which denotes the meaning of 'goods', we need to devise an new categorization that separates such properties into cultural heritage and natural heritage under the national heritage framework. Second, the designation criteria for natural monuments should be divided into the individual realm for animals and plants respectively, since they are not divided in the current Act. Third, the guidelines for naming of natural monuments should be established with the following new categories in accordance with the clear standards. Fourth, such imbalances require us to give priority to the relatively neglected types and areas. Fifth, as the big and old trees account for more than a half of the designated plants, it is necessary to search out new resources(wet plant communities, seashores, sand dune plant communities, etc.) such as geological resources, mineral springs, hot springs, and fossils that are in danger of completely being exploited and exhausted. While most of the designated animals are protected nationally, the existing designation system is required to protect habitats and breeding places for the systematic and efficient conservation. Sixth, as long as we need to preserve those historical and cultural resources for the future generations from national and global perspectives, we should enhance their values by designating them as natural monuments even though they are protected by other regulations such as the natural environment area. Seventh, as a result of the survey, we found that more budgets and experts in the local governments, more empowered organizations, more active public participation should be provided for the better Natural Monument management in Korea. Eighth, the Lap of Natural Heritage in the National Research Institute of Cultural Heritage needs to be developed to the Natural Heritage Institute to conduct the diverse activities such as researches, restoration, exhibition and education programs in a systematic and efficient way. Ninth and the last, major damages to natural monuments can be generally categorized into the artificial one and natural one, respectively. The artificial damages include toxics, soil covering, excessive humidity, fire, construction and management works, unlawful damages, fishing, oil spillage, etc, and the natural ones include lightning, storms(typhoons), heavy snowfalls, damage by insects and diseases, lack of prey, etc. This study will become meaningful in that it proposes specific measures for the improvement of the institutions, designation, and management of natural monuments on the basis of the comprehensive analysis on natural monuments. We wish to leave the other subjects related with this study to the future researches.

Methods that can be Substituted for Earth Healing of Seedling by Using the Plastic Vinyl and their Micro-climatical Characteristics (프라스틱비닐제품(製品)을 이용(利用)한 가식대치방법(假植代置方法)과 미기상학적(微氣象學的) 특성(特性))

  • Ma, Sang Kyu;Lee, Jang Soo
    • Journal of Korean Society of Forest Science
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    • v.47 no.1
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    • pp.44-51
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    • 1980
  • In order to find out the suitable methods that can omit the earth healing and increase the survival through improving the seedling-healing and transportable methods. Several trials with plastic vinyl have been done and its results are as follows: 1. Though P. rigitaeda seedling have been stored in the black and white vinyl sack for 35 days in the storehouse. This seedling have survived with very high percentage as Table 1. This means that the earth healing work at the nursery or planting area can be omitted if seedling sould be stored in the storehouse by using the vinyl sack. The possibilities of long-period storage in the black and white vinyl sack seem to be come from the reasons that air humidity in the sack is nearly 100% and its air temperature is only around $15^{\circ}C$ with very little difference between day and night time. This sack also can be utilized in place of the planting sack, and though this sack with seedling have been laid under direct sunshine for 1 to 2 days. Any difference between the sack stored in the storehouse has not been observed on the survival specially Table 2. 2. When the bundled seedling have been covered with the black and white vinyl instead of earth healing, even if these seedling have been laid for 18 days under the vinyl. This seedling show us high survival as Table 3. High humidity with nearly 95%, very little difference of air temperature between day and night time under the vinyl and not so big difference between out-and inside temperature could be reasons of high survival to be considered. So through covering by the black and white vinyl. The labour power for earth healing works can be saved also. 3. In order to protect the healed seedling from the direct sunshine and the eva-transpiration. Black vinyl net and reed mat could be effective for this purpose. Because vinyl net could intercept around one to third, reed mat two to third of total solar energy and also suppress more than 50% of total water loss by the transpiration.

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Effect of Inorganic Environmental Factors on the Growth of Pinus koraiensis Seedlings (I) - The Influence of Shading on the Growth of Seedlings Grown on the Seed Bed - (무기적(無機的) 환경요인(環境要因)이 잣나무 유묘(幼苗)의 생육(生育)에 미치는 영향(影響)에 관(關)한 연구(硏究)(I) - 파종상(播種床)에 있어서의 피음처리(被陰處理) 영향(影響) -)

  • Kim, Young Chai
    • Journal of Korean Society of Forest Science
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    • v.73 no.1
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    • pp.43-54
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    • 1986
  • This study was carried out to investigate the influence of light intensity on the growth of Korean white pine (Pinus koraiensis) seedlings. The seedlings were grown under four different relative light intensities: 100%, 63%, 37%, and 19% of full sunlight by covering with saran screen on seed bed. The results obtained were summarized as follows; 1. The highest shoot elongation was found at 37% in relative light intensity (RLI) plot, and the best growth in root, seedling length and diameter increment appeared at 100% on RLI plot. Contribution rates of shading to growth in shoot elongation, root growth, seedling length, and diameter increment were 9.3%, 26.2%, 21.0%, and 48.7%, respectively. 2. The greatest number of one-year-old needle fascicle was found at 100% in RLI plot, whereas that of two-year-old needle fascicle appeared at 37% in RLI plot. The contribution rate of the light intensity to number of needle fascicle was 3.9% and factor of leaf age contributed to number of needle fascicle in 27.8%. The length of needles grown under different light intensities varied with needle ages. The longest length of new needles appeared at 37% in RLI plot, but old needles were not clear in influence of light intensity. The contribution rate to needle length by the light intensity was 2.5%. 3. The heaviest value of the fresh and dry weight of seedlings appeared at 100% of RLI plot then decreased with light intensity. The contribution rates to fresh and dry weight by the shading were 38% and 7.6% respectively. 4. The largest value of the dry weight of needles appeared at 100% of RLI plot and then decreased with light intensity. The contribution rates to dry weight of needles by the light intensity was 13.18%. 5. The values of T/R ratio increased with decreased light intensity and the contribution rate was 7.0%. 6. Positive correlation and linear regressions were recognized between dry weight of leaf and other factors (dry weight of shoot, root, seedling and diameter increment).

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Characteristics of the Electro-Optical Camera(EOC) (다목적실용위성탑재 전자광학카메라(EOC)의 성능 특성)

  • Seunghoon Lee;Hyung-Sik Shim;Hong-Yul Paik
    • Korean Journal of Remote Sensing
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    • v.14 no.3
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    • pp.213-222
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    • 1998
  • Electro-Optical Camera(EOC) is the main payload of the KOrea Multi-Purpose SATellite(KOMPSAT) with the mission of cartography to build up a digital map of Korean territory including a Digital Terrain Elevation Map(DTEM). This instalment which comprises EOC Sensor Assembly and EOC Electronics Assembly produces the panchromatic images of 6.6 m GSD with a swath wider than 17 km by push-broom scanning and spacecraft body pointing in a visible range of wavelength, 510~730 nm. The high resolution panchromatic image is to be collected for 2 minutes during 98 minutes of orbit cycle covering about 800 km along ground track, over the mission lifetime of 3 years with the functions of programmable gain/offset and on-board image data storage. The image of 8 bit digitization, which is collected by a full reflective type F8.3 triplet without obscuration, is to be transmitted to Ground Station at a rate less than 25 Mbps. EOC was elaborated to have the performance which meets or surpasses its requirements of design phase. The spectral response, the modulation transfer function, and the uniformity of all the 2592 pixel of CCD of EOC are illustrated as they were measured for the convenience of end-user. The spectral response was measured with respect to each gain setup of EOC and this is expected to give the capability of generating more accurate panchromatic image to the users of EOC data. The modulation transfer function of EOC was measured as greater than 16 % at Nyquist frequency over the entire field of view, which exceeds its requirement of larger than 10 %. The uniformity that shows the relative response of each pixel of CCD was measured at every pixel of the Focal Plane Array of EOC and is illustrated for the data processing.