• Title/Summary/Keyword: low-loss

Search Result 5,088, Processing Time 0.044 seconds

Study on 3D Printer Suitable for Character Merchandise Production Training (캐릭터 상품 제작 교육에 적합한 3D프린터 연구)

  • Kwon, Dong-Hyun
    • Cartoon and Animation Studies
    • /
    • s.41
    • /
    • pp.455-486
    • /
    • 2015
  • The 3D printing technology, which started from the patent registration in 1986, was a technology that did not attract attention other than from some companies, due to the lack of awareness at the time. However, today, as expiring patents are appearing after the passage of 20 years, the price of 3D printers have decreased to the level of allowing purchase by individuals and the technology is attracting attention from industries, in addition to the general public, such as by naturally accepting 3D and to share 3D data, based on the generalization of online information exchange and improvement of computer performance. The production capability of 3D printers, which is based on digital data enabling digital transmission and revision and supplementation or production manufacturing not requiring molding, may provide a groundbreaking change to the process of manufacturing, and may attain the same effect in the character merchandise sector. Using a 3D printer is becoming a necessity in various figure merchandise productions which are in the forefront of the kidult culture that is recently gaining attention, and when predicting the demand by the industrial sites related to such character merchandise and when considering the more inexpensive price due to the expiration of patents and sharing of technology, expanding opportunities and sectors of employment and cultivating manpower that are able to engage in further creative work seems as a must, by introducing education courses cultivating manpower that can utilize 3D printers at the education field. However, there are limits in the information that can be obtained when seeking to introduce 3D printers in school education. Because the press or information media only mentions general information, such as the growth of the industrial size or prosperous future value of 3D printers, the research level of the academic world also remains at the level of organizing contents in an introductory level, such as by analyzing data on industrial size, analyzing the applicable scope in the industry, or introducing the printing technology. Such lack of information gives rise to problems at the education site. There would be no choice but to incur temporal and opportunity expenses, since the technology would only be able to be used after going through trials and errors, by first introducing the technology without examining the actual information, such as through comparing the strengths and weaknesses. In particular, if an expensive equipment introduced does not suit the features of school education, the loss costs would be significant. This research targeted general users without a technology-related basis, instead of specialists. By comparing the strengths and weaknesses and analyzing the problems and matters requiring notice upon use, pursuant to the representative technologies, instead of merely introducing the 3D printer technology as had been done previously, this research sought to explain the types of features that a 3D printer should have, in particular, when required in education relating to the development of figure merchandise as an optional cultural contents at cartoon-related departments, and sought to provide information that can be of practical help when seeking to provide education using 3D printers in the future. In the main body, the technologies were explained by making a classification based on a new perspective, such as the buttress method, types of materials, two-dimensional printing method, and three-dimensional printing method. The reason for selecting such different classification method was to easily allow mutual comparison of the practical problems upon use. In conclusion, the most suitable 3D printer was selected as the printer in the FDM method, which is comparatively cheap and requires low repair and maintenance cost and low materials expenses, although rather insufficient in the quality of outputs, and a recommendation was made, in addition, to select an entity that is supportive in providing technical support.

Severe Outbreak of Rice Stripe Virus and Its Occurring Factors (벼줄무늬잎마름바이러스의 대 발생과 발생 요인)

  • Kim, Jeong-Soo;Lee, Gwan-Seok;Kim, Chang-Seok;Choi, Hong-Soo;Lee, Soo-Heon;Kim, Mi-Kyeong;Kwag, Hae-Ryun;Nam, Mun;Kim, Jeong-Sun;Noh, Tae-Hwan;Kang, Mi-Hyung;Cho, Jeom-Deog;Kim, Jin-Young;Kang, Hyo-Jung;Han, Jong-Woo;Kim, Byung-Ryun;Jeong, Sung-Soo;Kim, Ju-Hee;Kuo, Sug-Ju;Lee, Jung-Hwan;Kim, Tae-Sung
    • The Korean Journal of Pesticide Science
    • /
    • v.15 no.4
    • /
    • pp.545-572
    • /
    • 2011
  • The genetic diagnosis methods by RT-PCR and Virion capture (VC)/RT-PCR against Rice stripe virus (RSV) were developed. Three diagnosis methods of seedling test, ELISA and RT-PCR were compared in virus detection sensitivity (VDS) for RSV. The VDS of ELISA for RSV viruliferous small brown plant hopper (SBPH) was higher with 40.5% than that of seedling test. The VDS of RT-PCR was higher with 21% than that of ELISA. The VDS of ELISA and VC/RT-PCR was same with 9.2% in average on the SBPH collected from fields at the areas of Gimpo, Pyungtaeg and Sihueng, Gyeonggi province in 2009. The specific primers of RSV for SBPH and rice plant were developed for the diagnosis by Real time PCR. The RQ value of Real time PCR for the viruliferous and non viruliferous SBPH was 1 for 50 heads of non viruliferous SBPH, 96.5 for 50 heads of viruliferous SBPH, 23.1 for 10 heads of viruliferous SBPH + 40 heads of non viruliferous SBPH, and 75.6 for 30 heads of viruliferous SBPH + 20 heads of non viruliferous SBPH. The RQ value was increased positively by the ratio of viruliferous SBPH. Full sequences of 4 genomes of RSV RNA1, RNA2, RNA3 and RNA4 were analysed for the 13 RSV isolates from rice plants collected from different areas. Genetic relationships among the RSV isolates of Korea, Japan and China were classified as China + Korea, and China + Korea + Japan by phylogenetic analysis for RSV RNA1 and RNA2. In case of RNA3 involved in pathogenicity, genetic relationship of RSV among the three countries was grouped into 3 as China, China + Korea, and Korea + Japan. According to the genetic relationships in RSV RNA4, RSV isolates were grouped into 4 as China, Korea, China + Korea + Japan, and Korea + Japan. Viruliferous insect rate (VIR) of RSV in average increased in each year from 2008 to 2010, and the rates were 4.3%, 6.1%, and 7.2%, respectively, at the 28 major rice production areas in 7 provinces including Gyeonggido. The highest VIR in each year was 11.3% of Gyeonggido in 2008, 20.1% of Jellanamdo in 2009 and 14.2% of Chungcheongbukdo in 2010. The highest VIR depending upon the investigated areas was 22.1% at Buan of Jellabukdo in 2008, 36% at Wando and Jindo of Jellanamdo in 2009, and 30.0% at Boeun of Chungcheongbukdo in 2010. Average population density (APD) of overwintered SBPH was 13.1 heads in 2008, 13.9 heads in 2009 and 5.6 heads in 2010. The highest APD was 39.1 and 60.4 heads at Buan of Jellabukdo in 2008 and 2009, respectively, and 14.0 heads at Pyungtaeg of Gyeonggido. The acreage of RSV occurred fields was 869 ha in the western and southern parts, mainly at Jindo and Wando areas, of Jellanamdo in 2008. In 2009, RSV occurred in the acreage of 21,541 ha covered whole country, especially, partial and whole plant death were occurred with infection rate of 55.2% at 3,025 plots in 53 Li, 39 Eup/Myun, 19 Si/Gun of Gyeonggido, Incheonsi, Chungcheongnamdo, Jeollabukdo and Jeollanamdo. Seasonal development of overwintered SBPH was investigated at Buan, Jeollabukdo, and Jindo, Jeollanamdo for 3 years from 2008. Most SBPH developed to the 3rd and 4th instar on the periods of May 20 to June 10, and they developed to the adult stage for the 1st generation on Mid and Late June. In 2009, all SBPH trapped by sky net trap were adult on May 31 to June 1 at Mid-western aeas of Taean, Seosan and Buan, and South-western areas of Sinan and Jindo. The population density of adult SBPH was 963 heads at Taean, 919 at Seocheon and 819 at Sinan area. The origin of these higher population of adult SBPH were verified from the population of non-overwintered SBPH but immigrant SBPH. From Mid May to Mid June in 2010, adult SBPH could not be counted as immigrant insects by sky net trap. The variation of RSV VIR was high with 2.1% to 9.5% for immigrant adult SBPH trapped by sky net trap at Hongsung of Chungcheongbukdo, Buan of Jeollabukdo and so forth in 2009. The highest VIR for the immigrant adult SBPH was 9.5% at Boryung of Chungcheongnamdo, followed by 7.9% at Hongsung of Chungcheongnamdo, 6.5% at Younggwang of Jeollanamdo, and 6.4% at Taean of Cheongcheongnamdo. The infection rate of RSV on rice plants induced by the immigrant adult SBPH cultivated near sky net trap after about 10 days from immigration on June 12 in 2009 was 84.6% at Taean, 65.4% at Buan and 92.9% at Jindo, and 81% in average through genetic diagnosis of RT-PCR. Barley known as a overwintering host plant of RSV had very low infection rate of 0.2% from 530 specimens collected at 10 areas covering whole country including Pyungtaeg of Gyeonggido. Twenty nine plant species were newly recorded as natural hosts of RSV. In winter annual plant species, 11 plants including Vulpia myuros showed RSV infection rate of 24.9%. The plant species in summer annual ecotype were 13 including Digitaria ciliaris with 44.9%, Echinochloa crusgalli var. echinata with 95.2% and Setaria faberi with 65.5% in infection rate of RSV. Five perennial plants including Miscanths sacchariflorus with infection rate of 33.3% were recorded as hosts of RSV. Rice cultivars, 8 susceptible cultivars including Donggin1 and 17 resistant ones including Samgwang, were screened in field conditions at 3 different areas of Buan, Iksan and Ginje in 2009. All the susceptible cultivars were showed typical symptom of mosaic and wilt. In 17 genetic resistant cultivar, 12 cultivars were susceptible, however, 5 cultivars were field-resistant plus genetic resistant to RSV as non symptom expression. When RSV was artificially inoculated at seedling stage to 4 cultivars known as genetic resistant and 3 cultivars known as genetic susceptible, the symptom expression in resistant cultivars was lower as 19.3% in average than that of 53.3% in susceptible ones. In comparison of symptom expression rate and viral infection rate using resistant Nampyung and susceptible Heugnam cultivars by artificial inoculation of RSV at seedling stage, the symptom expression of Heugnam was higher as 28% than 12% of Nampyung. However, virion infection of resistant Nampyung cultivar was higher as 12% reversely than 85% of susceptible Heugnam. Yield loss of rice was investigated by the artificial inoculation of RSV at the seedling stage of resistant cultivars of Nampyung and Onnuri, and susceptible cultivars of Donggin1 and Ungwang for 3 years from 2008. The average yield per plant was 7.8 g, 8.5 g and 13.8 g on rice plants inoculated at seedling stage, tillering stage and maximum tillering stage, respectively. The yield loss rate was increased by earlier infection of RSV with 51% at seedling stage, 46% at tillering stage and 13% at maximum tillering stage. In resistant rice cultivars, there was no statistically significant relation between infection time and yield loss. In natural fields on susceptible rice cultivar of Ungwang at Taean and Jindo areas in 2009, the yield loss rate was increased with same tendency to the infection hill rate having the corelation coefficient of 0.94 when the viral infection was over 23.4%.

Transformation of Nitrogen Derived from Solid Piggery Manure in Soil under Aerobic or Anaerobic Incubation Condition (혐기(嫌氣) 및 호기조건하(好氣條件下)에서 토양처리(土壤處理)된 돈분(豚糞) 중(中) 질소형태변화(窒素形態變化))

  • Yun, Sun-Gang;Jung, Kwang-Yong;Yoo, Sun-Ho
    • Korean Journal of Soil Science and Fertilizer
    • /
    • v.26 no.2
    • /
    • pp.121-126
    • /
    • 1993
  • The behaviors of inorganic nitrogen derived from solid animal waste in soil has been received too much concern partly because nitrate which occurred from nitrification can act as a pollutant to soil and groundwater and partly because the loss of nitrogen from surface soil by downward movement of water is disadvantageous in the view of plant nutrient. This present study was conducted to get fundamental imformations on nitrogen behavior and to provide improved basical concepts on the management of animal waste. Fresh or fermented pig manure was mixed with a sandy loam soil in the ratio of 2:1(soil:pig manure), packed into test tube and incubated at $30^+/-1^{\circ}C$ for 8 weeks under aerobic- or anaerobic condition. Sample tubes were taken at the one week interval and analyzed on pH, the amount of $CH_4$ produced under anaerobic condition and inorganic nitrogen. The pH of soil treated with fresh pig manure under anaerobic condition was lowered by 1.87 unit compared to that of under aerobic condition, but at the treatment with fermented pig manure, pH change was very little between aerobic and anaerobic condition. The coefficients of regressional equations which were obtained from pH and incubation time were -0.114 in fresh pig manure and -0.089 in fermented pig manure, and the extent of pH decrease due to incubation was greater in fresh pig manure than that of fermented pig waste. No differences in the amounts of $CH_4$ produced under anaerobic condition between fresh and fermented pig manure was observed until 3 weeks of incubation, however, after that the amount of $CH_4$ produced in fresh pig manure was abruptly increased and cumulative amont of $CH_4$ was reached 8.6 mole/g. K values on $CH_4$ production in fresh and fermented pig manure was 0.211 mole/g/day and 0.046 mole/g/day, respectively, for 5 weeks from the 3rd to the 8th week. $NH_4-N$ concentration at aerobic condition with fresh pig manure treatment was lowered by passing time of incubation, but $NO_3-N$ concentration was elevated from 11.2 ppm at initial state to 67.3 ppm after incubation and this trend on $NH_4-N$, $NO_3-N$ concentration was very similar to the treatment of fermented pig manure. While $NH_4-N$ concentration under anaerobic condition was greatly increased. $NO_3-N$ concentartion was not only very low but also no great changes, that was ranged from 4 to 8 ppm.

  • PDF

CQI Action Team Approach to Prevent Pressure Sores in Intensive Care Unit of an Acute Hospital Korea (중환자의 욕창 예방 연구 : 욕창 예방 QI팀을 중심으로)

  • Kang, So Young;Choi, Eun-Kyung;Kim, Jin-Ju;Ju, Mi-Jung
    • Quality Improvement in Health Care
    • /
    • v.4 no.1
    • /
    • pp.50-63
    • /
    • 1997
  • Background : A pressure sore was defined as any skin lesion caused by unrelieved pressure and resulting in damage to underlying tissue. The health care institutions in the United States were reported the incident rate of pressure sores ranging from 6 to 14 %. Intensive Care Unit needed highest quality of care has been found over 40% incidence rate of pressure sore. Also, Annual expenditures for the care of pressure sores in patients in the United States have been estimated to be $7.5 billion; furthermore, 50 percent more nursing time is required to care for patients with pressure sore in comparison to the time needed to implement preventive measures against pressure sore formation. However, In Korea, there were little reliable reports, or researches, about incidence rates of pressure sore in health care institution including intensive care unit and about the integrated approach like CQI action team for risk assessment, prevention and treatment of pressure ulcers. Therefore, this study was to develop pressure sore risk assessment tool and the protocol for prevention of pressure sore formation through CQI action team activities, to monitor incident rate of pressure sore and the length of sore formation for patients at high risk, and to approximately estimate nursing time for sore dressing during research period as the effect of CQI action team. Method : CQI action team in intensive care unit, launched since early 1996, reviewed the literature for the standardized risk assessment tool, developed the pressure sore assessment tool based on the Braden Scale, tested its validity, compared on statistics including incidence rate of pressure sore for patients at high risk. Throughout these activities, CQI action team was developed the protocol, called as St. Marys hospital Intensive Care Unit Pressure Sore Protocol, shifted the emphasis from wound treatment to wound prevention. After applied the protocol to patients at high risk, the incident rate and the period of prevention against pressure development were tested with those for patients who received care before implementation of protocol by Chi-square and Kaplan-Meier Method of Survival Analysis. Result : The CQI action team found that these was significant difference of in incidence rate of pressure sores between patients at high risk (control group) who received care before implementation of protocol and those (experimental group) who received it after implementation of protocol (p<.05). 25% possibility of pressure sore formation was shown for the patients with 6th hospital day in ICU in control group. In experimental group, the patients with 10th hospital day had 10% possibility of pressure sore. Therefore, there was significant difference(p<.05) in survival rate between two groups. Also, nursing time for dressing on pressure sore in experimental group was decreased as much as 50% of it in control group. Conclusion : The collaborative team effort led to reduced incidence, increased the length of prevention against pressure sore, and declined nursing care times for sore dressing. However, there have had several suggestions for future study. The preventive care system for pressure sore should be applied to patients at moderate, or low risk throughout continuous CQI team activities based on Bed Sore Indicator Fact Sheet. Hospital-wide supports, such as incentives, would be offered to participants for keeping strong commitment to CQI team. Also, Quality Information System monitoring incidents and estimating cost of poor quality, like workload (full time equivalence) or financial loss, regularly in a hospital has to be developed first for supporting CQI team activities as well as empowering hospital-wide QI implementation. Being several limitations, this study would be one of the report cards for the CQI team activities in intensive care unit of an acute hospital and a trial of quality improvement of health care in Korea.

  • PDF

Effect of Non-perforated Breathable Films on the Shelf Life and Quality of Ferulae Mushroom (Pleurotus ferulae) during MA Storage at Different Temperatures (몇가지 저장온도와 비천공 Breathable 필름이 아위버섯(Pleurotus ferulae) 저장수명과 품질에 미치는 영향)

  • Choi, In-Lee;Son, Jin Sung;Kim, Young Jae;Kwon, Tae Ho;Kang, Ho-Min
    • Journal of Bio-Environment Control
    • /
    • v.21 no.3
    • /
    • pp.261-266
    • /
    • 2012
  • This study was carried out in order to investigate the effect of MA packaging material on quality and shelf life of ferulae mushroom (Pleurotus ferulae) at 1, 8, and $24^{\circ}C$ storage temperatures. We found that the fresh weight loss was less than 1.5% in all temperatures (1, 8, and $24^{\circ}C$) and non-perforated breathable films (1,300 cc, 3,000 cc, 5,000 cc, 7,000 cc, 10,000 cc, 15,000 cc, 20,000 cc, and $40,000cc/m^2{\cdot}day{\cdot}atm$ oxygen transmission rate) treatments. The proper MA packaging material of ferulae mushroom was 1,300 cc and 3,000 cc films at $1^{\circ}C$ storage. Because 1,300 cc and 3,000 cc films showed proper level, 15% carbon dioxide and 5% oxygen concentration for MA storage, although the shelf life was higher in 1,300 cc (42 days) than 3,000 cc (38 days), and the ethylene concentration as well as off-order showed lower in 3,000 cc than 1,300 cc film. The 3,000 cc film was the most suitable for ferulae mushroom storage at $8^{\circ}C$, because atmosphere composition in package was not statistically significantly different among the film treatments. In addition, 3,000 cc film showed the second low ethylene concentration and the longest shelf-life of 19 days. The ferulae mushroom stored at $25^{\circ}C$ showed a vigorous respiration and resulted in an extreme CA condition in package at $5^{th}$ day after storage, and showed the highest visual quality in 1,300 cc film. As the shelf life of ferulae mushroom at $1^{\circ}C$ and $8^{\circ}C$ storage were 8 times and 4 times longer than at $25^{\circ}C$ storage respectively, so the ferulae mushroom should be stored and distributed in cold chain system.

Pedogenesis of Forest Soils(Kandiustalfs) Derived from Granite Gneiss in Southern Part of Korea (우리나라 남부지역(南部地域) 화강편마암질(花崗片麻巖質) 삼림토양(森林土壤)의 토양생성(土壤生成))

  • Cho, Hi Doo
    • Journal of Korean Society of Forest Science
    • /
    • v.86 no.2
    • /
    • pp.186-199
    • /
    • 1997
  • The soils derived from granite gneiss occupy almost one third of the land area in Korea. The soils under forest vegetation, formed on granite gneiss, in Sun chon-shi, Chollanam-do in southern part of Korea, were studied to evaluate the weathering and the transformation of primary minerals into secondary minerals, clay minerals. The studied soils contained large amounts of ferromagnesian minerals, weathered biotites and were well weathered, strongly acid and low in organic matters and in ration exchange capacity. The clay contents in the Bt horizon were almost two times higher than those in the C horizon. The O horizon had a thin layer which consisted of a little decomposed plant components with a granic fabric and high porosity, and showed the micromorphological characteristics of moder humus. The related distribution pattern of the E horizon were enaulic and large amounts of silts and small amounts of sand grains were another characteristics of the E horizon. The most striking micromorphological features were multilaminated clay coating and infillings in the voids in the Bt and C horizons, and generally limpid ferriargillans ejected from the biotites and imparted red color to the soils in the Bt horizon. High clay contents in the Bt horizon was not only due to clay translocation, but also due to intensive in situ mineral weathering in this horizon. The most significant pedogenic process, revealed by the petrographic microscope and SEM, was the formation of iron oxides from biotites, the formation of tubular halloysites and the weathering models of biotites; wedge weathering and layer weathering. The thick coating on the weathering biotites showed the characteristics of the weathering process and the synthetic hematites were revealed in clays by TEM. Total chemical analysis of clays revealed extensive loss of Ca, and Na and the concentration of Fe and Al. Mineralogical studies of clays by XRD showed that micas were almost completely weathered to kaolinite, vermiculite-kaolinite intergrade, hematite, gibbsite, while halloysites from other primary minerals. Some dioctahedral mica appeared to be resistant in the soils. Parent rock of the soils contained a considerable amounts of biotites and this forest soils showed especially a dominant characteristics of biotite weathering.

  • PDF

An Analysis of Growth Status and Soil Environment in Camellia japonica L. Forest at Jeolla-province Natural Monuments (동백나무 숲의 생육현황 및 토양환경 분석 - 전라도 지방 천연기념물 동백나무 숲을 중심으로 -)

  • Lee, Won-Ho
    • Journal of the Korean Institute of Traditional Landscape Architecture
    • /
    • v.31 no.3
    • /
    • pp.1-11
    • /
    • 2013
  • In this study, based on a natural monument forest research by Camellia japonica L. Forest appointed as a natural monument located environment and growth environment and the soil environment, Camellia japonica L. Forest soil in order to analyze effects of soil in Camellia japonica L. Forest correlation analysis the results can be summarized as follows: First, a natural monument Camellia japonica L. forest located on the foot of a mountain valley or within the stream, a lot of sunshine southeast, east, and south in the direction of the share due to external factors, making it a good, but, $15{\sim}30^{\circ}$ of distributed in the soil slopes in the slope there is a risk of loss are appearing. Second, the growth of the Status of Camellia japonica L. forest represents the distribution of the uneven-aged forest diameter class. but increases the density of the upper forest trees Camellia japonica L. occurred in lower saplings do not have growth. The width of crown diameter class caused a narrow oppressed tree, the average tree height in the 8.09m, camellia in common was lower than that of tree height, variation diameter class in the width of crown distribution severe low correlations were analyzed. Third, the natural monument Camellia japonica L. forest soil composition, properties of soil pH, etc. 10 entries were analyzed components of the soil. In summary analysis properties of soil, soil pH, calcium, organic matter, magnesium was good and potassium content was insufficient, nitrogen and phosphorus were excess. Fourth, the growth condition of Camellia japonica L. forest and soil physicochemical properties, the results of the correlation analysis. magnesium, calcium, nitrogen affects the growth of Camellia japonica L. forest. Other seven kinds of items showed no effect on growth. Current Status and Future Growth of Camellia japonica L. forest soil and soil environments as well as the relationship between, Camellia Forest Factors affecting the growth of the state in terms of long-term ecological research and conservation status of settled Camellia japonica L. forest research for building materials there will be continued.

Effects of various CLEAN-UP techniques on enamel surface roughness (수종의 CLEAN-UP technique이 법랑질 표면거칠기에 미치는 영향)

  • CHO, Sang-Wan;KWON, Oh-Won
    • The korean journal of orthodontics
    • /
    • v.27 no.5 s.64
    • /
    • pp.791-800
    • /
    • 1997
  • Sixty premolars extracted for orthodontic treatment were divided into four groups, and the residual resin was removed with four different rotary finishing instruments at a fixed speed of $18,500{\pm}300 rpm$ on the low speed handpiece. The instruments were G1; No.169L carbide fissure bur, G2: No.2 round bur, G3; No.4 round bur, G4: No.8 round bur. Then, the enamel received a S-second polishing with a rubber cup and a pumice. To find the extent of loss on the enamel at this point, prophylaxis was done with the rubber cup and pumice prior to bonding of the bracket(P1) and removal of residual resin by means of appropriate procedure applicable to each respective group(P2) followed. The final polishing was done with the rubber cup and pumice(P3), and the enamel surface roughness was measured each by the surface measuring instrument. The whole process was observed under a scanning electron microscope to gain the following results: At P2, the enamel surface roughness in G1 showed most smoothly with $2.60{\pm}0.55{\mu}m;\;in\;G2,\;3.24{\pm}0.80{\mu}m;\;in\;G3,\;3.44{\pm}0.94{\mu}m;\;in\;G4,\;3.89{\pm}0.54{\mu}m$, the roughest. G2 and G3 showed no statistical significance(P>0.05). At P3, the enamel surface roughness in G1 showed most smoothly with $2.29{\pm}0.47{\mu}m;\;in\;G2,\;2.44{\pm}0.56{\mu}m;\;in\;G3,\;2.44{\pm}0.56{\mu}m;\;in\;G4,\;2.92{\pm}0.43{\mu}m$, the roughest. G1 vs G2, G3, and G2 vs G3 had no statistical significances(p>0.05). In all groups, P2 and P3 showed rougher in surface roughness than P1, and P2 rougher than P3(p<0.01). In a case of 5-second prophylaxis with the rubber cup and the pumice on a virgin, normal enamel, fine scratches were found under the scanning electron microscope. In all four groups, unremovable gouges remained even after polishing with the ubber and pumice; residual resin was not observed with naked eye when finished with the rubber and pumice, but the resin debris was observed under the scanning electron microscope.

  • PDF

The Impact of Nakdong Estuarine Barrage on Distribution of Biogenic Silica (BSi) in Surface Sediment (하구둑이 낙동강 하구 표층 퇴적물 생규소(BSi) 분포에 미치는 영향)

  • KIM, YUNJI;AN, SOONMO
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
    • /
    • v.22 no.4
    • /
    • pp.172-186
    • /
    • 2017
  • Current study is a part of the efforts to assess the estuarine barrage effects on the coastal ecosystem induced by the Si flux changes. Surface sediments from Seomjin and Nakdong estuary and sediment cores from Nakdong estuary was analysed to investigate the effect of estuarine barrage on the distribution of grain size, organic matter (loss on ignition: LOI) and biogenic silica (BSi). The samples of Seomjin estuary were collected in March, 2015 and those of Nakdong estuary were collected in November, 2014. Generally, the longitudinal distribution of grain size, LOI and BSi in Seomjin estuary, natural estuary, was gradually changed. However mud (silt and clay), LOI and BSi increased from station mid-estuary where tide reaches year-round. The distribution of grain size, LOI and BSi in Nakdong estuary, however, were entirely different between inside and outside of estuarine barrage. The mud percentage and LOI were low and consistent in inside of the barrage except R05, inside of right gate, yet those of outside of the barrage were higher and varied by adjacent sluices. Mud, LOI and BSi of ND1 and ND2 decreased immediately after the construction of Nakdong estuarine barrage due to disturbance of sediment and decrease of sediment supply. To exclude the physical effects by the barrage, BSi excess ($BSi_{exc}$) was calculated using regression equation of BSi-LOI and BSi-mud of Seomjin estuary. $BSi_{exc}$ of Seomjin estuary decreased gradually from upper estuary to lower estuary. $BSi_{exc}$ of Nakdong estuary were positive in inside of the barrage and negative in outside of the barrage. BSi retention and shift of species composition of diatom by the barrage would affect $BSi_{exc}$ distribution. Before the construction of Nakdong estuarine barrage, $BSi_{exc}$ of ND2 was negative and consistent owing to high mud sedimentation. After the construction, $BSi_{exc}$ of ND2, however, fluctuated due to continuous disturbance of sediment due to construction of Eulsuk bridge and East gate.

A Study on the Conservation and Management of the Village Forest in Gyeonggi-do (경기도 마을숲의 보전 및 관리에 관한 연구)

  • Hwang, Dong-Kyu;Kim, Dong-Yeob
    • Journal of the Korean Institute of Traditional Landscape Architecture
    • /
    • v.33 no.4
    • /
    • pp.99-111
    • /
    • 2015
  • The objectives of this study were to investigate the location, shape, environment, and vegetation of the Village Forest in Gyeonggi-do and to evaluate the ecological integration and changes of the Village Forests to figure out the measures for conservation and management. There were 23 Village Forests remain in Gyeonggi-do. Ten Village Forests were established based on Feng-shui background. Many of them were found in Yongin area and southeast of Icheon. The Village Forests were owned by local community at 9 village and privately owned at 8 villages. Most Village Forests were managed by local communities except for the two managed by private person. Fifty-two percent of the Village Forests were in strip shape, and most of them were established by Feng-shui background or for the prevention of disasters. The average size of the Village Forests was relatively small at 3,046m2. The most frequent tree species found at the Village Forest were Zelkova serrata and Pinus densiflora. Over half of the number of Village Forests showed vertical structure of overstory trees only or overstory-sub overstory combination, which seemed to be resulted from the loss of understory plants by the activities of local residents. The Village Forests that had over 30% of damaged trees were found at 7 villages. The damages were caused by the road construction close to the groves, soil compaction, and tree death by covering lower stem with soil. The vitality of the damaged trees seemed to be significantly low compared to that of the undamaged. There were factors that determined the changes in the Village Forests: community ritual, institutional protection, designation as a water resource protection district, road construction, land use change, windstorm hazards, and development of forest areas. In order to conserve and manage the Village Forests appropriately, it is necessary to limit excessive use of the grove areas and maintain proper tree growing conditions by improving the soil environment. The development of neighborhood areas need to be controlled and community activities should be encouraged to maintain or restore the original landscape of the groves. Protection measures and supporting policies need to be enforced to keep the Village Forests from disappearing in near future.