• Title/Summary/Keyword: 과학성

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Comparison of adhesive strength of resinous teeth splinting materials according to enamel surface treatment (법랑질 표면 처리방법에 따른 레진계 치아 고정재료의 접착강도 비교)

  • Lee, Ye-Rim;Kim, Soo-Yeon;Kim, Jin-Woo;Park, Se-Hee;Cho, Kyung-Mo
    • Journal of Dental Rehabilitation and Applied Science
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    • v.35 no.2
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    • pp.72-80
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    • 2019
  • Purpose: The purpose of this study is to compare and analyze the shear bond strength and fracture pattern in different enamel tooth surface treatments for resin splinting materials. Materials and Methods: G-FIX and LightFix were used as tooth splinting materials. Twenty bovine mandibular incisors were used for the preparation of the specimens. The exposed enamel surface was separated into four parts. Each tooth was treated with 37% phosphoric acid, 37% phosphoric acid + adhesive resin, 37% phosphoric acid + G-premio bond, and G-premio bond for each fraction. Shear bond strength was measured using a universal testing machine. After measuring the shear bond strength, the fractured surface of the specimen was magnified with a microscope to observe the fracture pattern. Two-way ANOVA was used to verify the interaction between the material and the surface treatment method. One-way ANOVA was used for comparison between the surface treatment methods of each material and post-hoc test was conducted with Scheffe's test. An independent t-test was conducted to compare shear bond strengths between materials in each surface treatment method. All statistics were conducted at 95% significance level. Results: G-FIX, a tooth splinting resin, showed similar shear bonding strength when additional adhesive resins were used when material was applied after only acid etching, and LightFix showed the highest shear bonding strength when additional adhesive resins were used after the acid etching. In addition, both G-FIX and LightFix showed the lowest shear bond strength when only self-etching adhesive was applied without additional acid etching. Verification of interactions observed interconnection between resins and surface treatment methods. Most of the mixed failure was observed in all counties. Conclusion: When using G-FIX and LightFix, which are tooth-splinting materials, it is considered that sufficient adhesion will be achieved even after applying only acid etching as instructed by the manufacturer.

Feeding Effects of Whole Crop Rice based TMR on Growth Performance and Carcass Characteristics of Hanwoo Steers (사료용 벼 위주 TMR 급여가 거세 한우의 생장 능력 및 도체 특성에 미치는 영향)

  • Kim, Jong Geun;Zhao, Guoqiang;Liu, Chang;Nan, Wei Sheng;Kim, Hak Jin;Kim, Kyoung Hoon;Ahn, Eok Geun;Min, Hyung-Gyu
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.39 no.2
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    • pp.97-104
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    • 2019
  • This experiment was conducted to investigate the effect of whole crop rice (WCR) based TMR on growth performance and carcass characteristics of Hanwoo steers. WCR "Yeongwoo"was harvested at yellow ripen stage and ensiled for 60 days. The crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), in vitro dry matter digestibility (IVDMD) and total digestible nutrient (TDN) content was 8.4 %, 28.0 %, 53.8 %, 72.4 % and 66.8 %, respectively. For silage quality, pH was 4.37 and lactic and butyric acid content were 2.84 and 0.04 % in DM. Sixteen Hanwoo steers (8-mon-old) were allocated into either a control (commercial TMR) and WCR-TMR (WCR-based TMR) group. The TMR were fed according to the feeding stage phase: growing (Initiate~14 month), early fattening (15 month~21 month) and late fattening (22 month~30 month). The body weight of control group increased (P<0.05) until early fattening stage, but late growing stage of WCR-TMR group was higher than that of control (P<0.05). Average daily gain (ADG) was significantly greater (P<0.05) in WCR-TMR group (total 0.78 kg/head) compared to control (total 0.66 kg/head) except for late fattening stage. The marketing weight and carcass weight were higher in WCR-TMR group (726 vs 765 kg; 417.8 vs 450.4 kg). The back fat thickness (11.75 vs 13.00 mm), Longissimus dorsi area (88.00 vs $89.88cm^2$) and yield index (65.87 vs 64.30) were not different between the two groups (P>0.05) and also no difference in meat yield grade (A : B : C = 2 : 4 : 2). Marbling score (4.00 vs 4.13), meat color (4.75 vs 4.75), fat color (3.13 vs 2.88), texture (1.25 vs 1.50) and maturity (2.00 vs 2.00) were not significant difference between the two groups and meat quality grade ($1^{{+}{+}}:1^+:1:2:3=0:2:4:2:0$) was also not different. In conclusion, TMR feeding based on WCR silage showed superiority in carcass yield and ADG compared to control TMR. It is considered that the use of WCR for feed is a necessary option for the substitution of the imported forages and the government's policy for rice production adjustment.

Effects of Overwintering Disease Prevention in Korean Ginseng(Panax ginseng C.A. Meyer) by an Agronomical Control Measure in Paddy Field (논 재배 인삼의 월동병해 발생경감을 위한 경종적 처리효과)

  • Seong, Bong-Jae;Kim, Sun-Ick;Lee, Ka-Soon;Kim, Hyun-Ho;Kang, Yun Kyu;Cho, Jin-Woong
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.64 no.2
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    • pp.152-158
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    • 2019
  • This study was conducted to develop and prove the effects of an agronomical pest control measure on ginseng cultivated by direct seeding in paddy field, and the results obtained are as follows. Decomposition of ginseng in field during overwintering was due to gray mold rot caused by Botrytis cinerea, which occurred in October or November of 2016 and intensified in February and March the following year. The occurrence rate of gray mold rot based on shading materials was 6.5%, 16.8%, and 29.5% with light-proof paper, PE shade net, and rice straw shade, respectively. The initial infection occurred in the leaves prior to wintering and secondary infection occurred in the stems after wintering. The rate of screrotium formation by gray mold in the above-ground parts of ginseng tended to increase: 26.6% on October 20, 33.7% in November 20, and 41.8% on December 20. The force needed to remove the leaves and stems from withered ginseng was 0.2, 0.94, 2.5, and 5 kg for 1-, 2-, 3-, and 4- and 5-year holds; the force required was 1 kg after wintering, making it relatively easy to remove. The disease incidence rate after the removal of leaves and stems was 2.5%, 1.2%, and 2.2% in 4-, 5-, and 6-year-old plants, respectively, and a disease high incidence rate of 8.8%, 13.0%, and 18.2%, respectively, was seen when the leaves and stems were not removed. In both transplanting and direct seeding, the miss-planted rate decreased and the germination rate increased when shading material was removed and the surface of ridge was covered with soil or vinyl.

Effects of Specific Gravity on Germination and Emergence of Foxtail Millet (Setaria italica Beauvois) (염수선 종자 정선법에 따른 조의 발아 및 출현율)

  • Jung, Ki-Youl;Choi, Young-Dae;Chun, Hyen-Chung;Lee, Sang-Hun;Jeon, Seung-Ho
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.64 no.2
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    • pp.144-151
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    • 2019
  • The establishment rate of foxtail millet seeds is greatly affected by soil environment conditions. To enhance germination viability and stable production of foxtail millet seeds, it is important to select seeds with a high density. Therefore, this study tested the selection of high-quality seeds using salt solution (specific gravity: 1.000, 1.005, 1.010, 1.015, 1.020, 1.025, 1.030, 1.035, and $1.040g\;L^{-1}$) and investigated their germination rates, percentages of emergence, and seeding quality. In this study, three varieties were tested: 'Hwanggeum', 'Samdachal', and 'Kyeongkwan1'. The thousand seed weight of all three varieties increased proportionally with specific gravity. The highest thousand seed weight was observed at the selection with $1.040g\;L^{-1}$ specific gravity, which also had the highest germination rate of 88.3%, 86.7%, and 90.6%, for 'Hwanggeum'; 'Samdachal'; and 'Kyeongkwan1', respectively. The results of seeding quality indicated that higher the specific gravity during selection, the higher were the values of plant growth (plant height, leaf length, stem diameter, root length, root weight, and stem weight). All the three varieties were found to be longer or heavier for seeds selected at the specific gravity of $1.040g\;L^{-1}$. The packing germination viability investigation found that higher the specific gravity for selection of seeds, the higher was the percentage of emergence (PE) and the emergence rate index (ERI). The PE was the highest for seeds selected at $1.040g\;L^{-1}$ specific gravity (85.3, 83.0, and 87.0%), and ERI was also as high as $2.82d^{-1}\;m^{-1}$ or more at $1.040g\;L^{-1}$. Selection of seeds with salt solution resulted in high germination viability of foxtail millet. Therefore, sowing seeds selected at $1.040g\;L^{-1}$ specific gravity is expected to help substantially in increased productivity.

Estimation of Baseflow based on Master Recession Curves (MRCs) Considering Seasonality and Flow Condition (계절·유황특성을 고려한 주지하수감수곡선을 활용한 기저유출분리 평가)

  • Yang, Dongseok;Lee, Seoro;Lee, Gwanjae;Kim, Jonggun;Lim, Kyoung Jae;Kim, Ki-Sung
    • Journal of Wetlands Research
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    • v.21 no.1
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    • pp.34-42
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    • 2019
  • Baseflow which is one of the unmeasurable components of streamflow and slowly flows through underground is important for water resource management. Despite various separation methods from researches preceded, it is difficult to find a significant separation method for baseflow separation. This study applied the MRC method and developed the improved approach to separate baseflow from total streamflow hydrograph. Previous researchers utilized the whole streamflow data of study period at once to derive synthetic MRCs causing unreliable results. This study has been proceeded with total nine areas with gauging stations. Each three areas are selected from 3 domestic major watersheds. Tool for drawing MRC had been used to draw MRCs of each area. First, synthetic MRC for whole period and two other MRCs were drawn following two different criteria. Two criteria were set by different conditions, one is flow condition and the other is seasonality. The whole streamflow was classified according to seasonality and flow conditions, and MRCs had been drawn with a specialized program. The MRCs for flow conditions had low R2 and similar trend to recession segments. On the other hand, the seasonal MRCs were eligible for the baseflow separation that properly reflects the seasonal variability of baseflow. Comparing two methods of assuming MRC for baseflow separation, seasonal MRC was more effective for relieving overestimating tendency of synthetic MRC. Flow condition MRCs had a large distribution of the flow and this means accurate MRC could not be found. Baseflow separation using seasonal MRC is showing more reliability than the other one, however if certain technique added up to the flow condition MRC method to stabilize distribution of the streamflow, the flow conditions method could secure reliability as much as seasonal MRC method.

Development of Caregiver Guideline for Participation in Activities of Daily Living for the Elderly with Early Dementia: Focusing on the Delphi Survey (초기 치매 노인의 일상생활 참여 촉진을 위한 보호자 지침의 개발: 델파이 조사를 중심으로)

  • Kim, Seo-Eun;Koo, Seul-Gi;Park, Sang-M;Kim, Jung-Ran
    • 한국노년학
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    • v.37 no.2
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    • pp.461-474
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    • 2017
  • The purpose of this study was to develop the caregiver guideline for participation in activities daily living for the elderly with early dementia in home including easily adaptable and professional strategies as early intervetion. The process of this study was 3 stage. First stage, the development of preliminary caregiver guideline as the first stage of this study was to translate to Korean and reclassify the items about caregiver guideline for participation from reports of foreign association or government related dementia, and it consisted of 3 areas, 128 statements for questionnaire for Delphi investigation. Second stage, the guideline was to conduct the content validity, and delete, reclassify, integrate, revise inappropriate items through 2 rounds and 16 Delphi panels. Third stage, the establishment of the final version of caregiver guideline. It consisted of 8 areas: home modification and assistive device, home activities of daily living, health management, communication, psycho-emotional support, leisure activities, social participation, general strategies. All 68 items was arranged in important order. The content validity, stability, agreement index in this study were 0.81, 0.15, 0.79 respectively. When content validity, stability was above 0.49, below 0.5 in Delphi survey with 15 panels, it was not required additional survey. The result of this study meaned that it was not required to additional Delphi survey, and the result was stable and agreeable. This developed guideline was useful and practical to maintain the elderly's with dementia independent and healthy life as education materials for their caregivers, so it will expect to decrease caregiver's burden. Lastly, it stated limitation and suggestion for further study.

Assessing Impacts of Global Warming on Rice Growth and Production in Korea (지구온난화에 따른 벼 생육 및 생산성 변화 예측)

  • Shim, Kyo-Moon;Roh, Kee-An;So, Kyu-Ho;Kim, Gun-Yeob;Jeong, Hyun-Cheol;Lee, Deog-Bae
    • Journal of Climate Change Research
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    • v.1 no.2
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    • pp.121-131
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    • 2010
  • This study was carried out to evaluate spatial variations in rice production areas by simulating rice growth and yield with CERES-Rice growth model under GCM $2{\times}CO_2$ climate change scenarios. A modified window version(v4.0) of CERES-Rice was used to simulate the growth and development of three varieties, representing early, medium, and late maturity classes. Simulated growth and yield data of the three cultivars under the climate for 1971 to 2000 was set as a reference. Compared with the current normal(1971 to 2000), heading period from transplanting to heading date decreased by 7~8 days for the climate in $2^{\circ}C$ increase over normal, and 16~18 days for the climate in UKMO with all maturity classes, while change of ripening period from heading to harvesting date was different with maturity classes. That is, physical maturity was shortened by 1~3 days for early maturity class and 14~18 days for late maturity class under different climate change scenarios. Rice yield was in general reduced by 4.5%, 8.2%, 9.9%, and 14.9% under the climate in $2^{\circ}C$, $3^{\circ}C$, $4^{\circ}C$, and about $5^{\circ}C$ increase, respectively. The yield reduction was due to increased high temperature-induced spikelet sterility and decreased growth period. The results show that predicted climate changes are expected to bring negative effects in rice production in Korea. So, it is required for introduction of new agricultural technologies to adapt to climate change, which are, for example, developing new cultivars, alternations of planting dates and management practices, and introducing irrigation systems, etc.

Estimation of Change in Soil Carbon Stock of Pinus densiflora Forests in Korea using KFSC Model under RCP 8.5 Climate Change Scenario (한국형 산림토양탄소모델(KFSC Model)을 이용한 RCP 8.5 기후변화 시나리오 하에서의 국내 소나무림 토양탄소 저장량 장기 변화 추정 연구)

  • Park, Chan-woo;Lee, Jongyeol;Yi, Myongjong;Kim, Choonsig;Park, Gwan Soo;Kim, Rae Hyun;Lee, Kyeong Hak;Son, Yowhan
    • Journal of Climate Change Research
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    • v.4 no.2
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    • pp.77-93
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    • 2013
  • Global warming accelerates both carbon (C) input through increased forest productivity and heterotrophic C emission in forest soils, and a future trend in soil C dynamics is uncertain. In this study, the Korean forest soil carbon model (KFSC model) was applied to 1,467,458 ha of Pinus densiflora forests in Korea to predict future C dynamics under RCP 8.5 climate change scenario (RCP scenario). Korea was divided into 16 administrative regions, and P. densiflora forests in each region were classified into six classes by their stand ages : 1 to 10 (I), 11 to 20 (II), 21 to 30 (III), 31 to 40 (IV), 41 to 50 (V), and 51 to 80-year-old (VI+). The forest of each stand age class in a region was treated as a simulation unit, then future net primary production (NPP), soil respiration (SR) and forest soil C stock of each simulation unit were predicted from the 2012 to 2100 under RCP scenario and constant temperature scenario (CT scenario). As a result, NPP decreased in the initial stage of simulation then increased while SR increased in the initial stage of simulation then decreased in both scenarios. The mean NPP and SR under RCP scenario was 20.2% and 20.0% higher than that under CT scenario, respectively. When the initial age class was I, IV, V or VI+, predicted soil C stock under CT scenario was higher than that under RCP scenario, however, the countertrend was observed when the initial age class was II or III. Also, forests having a lower site index showed a lower soil C stock. It suggested that the impact of temperature on NPP was higher when the forests grow faster. Soil C stock under RCP scenario decreased at the end of simulation, and it might be derived from exponentially increased SR under the higher temperature condition. Thus, the difference in soil C stock under two scenarios will be much larger in the further future.

A Study for Activation Measure of Climate Change Mitigation Movement - A Case Study of Green Start Movement - (기후변화 완화 활동 활성화 방안에 관한 연구 - 그린스타트 운동을 중심으로 -)

  • Cho, Sung Heum;Lee, Sang Hoon;Moon, Tae Hoon;Choi, Bong Seok;Park, Na Hyun;Jeon, Eui Chan
    • Journal of Climate Change Research
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    • v.5 no.2
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    • pp.95-107
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    • 2014
  • The 'Green Start Movement' is a practical movement of green living to efficiently reduce the greenhouse gases originating from non-industrial fields such as household, commerce, transportation, etc. for the 'materialization of a low carbon society through green growth (Low Carbon, Green Korea)'. When the new government took office, following the Lee Myeongbak Administration that had presented 'Low Carbon, Green Growth' as a national vision, it was required to set up the direction of the practical movement of green life to respond to climate change persistently and stably as well as to evaluate the performance of the green start movement over the past 5 years. A questionnaire survey was administered to a total of 265 persons including public servants, members of environmental and non-environmental NGOs, participants of the green start movement and professionals. In the results of the questionnaire survey, many opinions have indicated that the awareness of the green start movement is increasing and the green start movement has had a positive impact on individual behavior and group behavior in terms of green living. The result shows, however, that the environmental NGOs don't cooperate sufficiently to create a 'green living' effect on a national scale. Action needs to be taken on the community level in order to generate a culture of environmental responsibility. The national administration office of the Green Start Movement Network should play the leading role between the government and environmental NGOs. The Green Start National Network should have greater autonomy and governance of the network needs to be restructured in order to work effectively. Also the Green Start Movement should identify specific local characteristics to support activities that reduce greenhouse gas emissions. Best practices can be shared to reduce greenhouse gas emissions by a substantial amount.

Stress distribution of molars restored with minimal invasive and conventional technique: a 3-D finite element analysis (최소 침습적 충진 및 통상적 인레이 법으로 수복한 대구치의 응력 분포: 3-D 유한 요소 해석)

  • Yang, Sunmi;Kim, Seon-mi;Choi, Namki;Kim, Jae-hwan;Yang, Sung-Pyo;Yang, Hongso
    • Journal of Dental Rehabilitation and Applied Science
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    • v.34 no.4
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    • pp.297-305
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    • 2018
  • Purpose: This study aimed to analyze stress distribution and maximum von Mises stress generated in intracoronal restorations and in tooth structures of mandibular molars with various types of cavity designs and materials. Materials and Methods: Three-dimensional solid models of mandible molar such as O inlay cavity with composite and gold (OR-C, OG-C), MO inlay cavity with composite and gold (MR-C, MG-C), and minimal invasive cavity on occlusal and proximal surfaces (OR-M, MR-M) were designed. To simulate masticatory force, static axial load with total force of 200 N was applied on the tooth at 10 occlusal contact points. A finite element analysis was performed to predict stress distribution generated by occlusal loading. Results: Restorations with minimal cavity design generated significantly lower values of von Mises stress (OR-M model: 26.8 MPa; MR-M model: 72.7 MPa) compared to those with conventional cavity design (341.9 MPa to 397.2 MPa). In tooth structure, magnitudes of maximum von Mises stresses were similar among models with conventional design (372.8 - 412.9 MPa) and models with minimal cavity design (361.1 - 384.4 MPa). Conclusion: Minimal invasive models generated smaller maximum von Mises stresses within restorations. Within the enamel, similar maximum von Mises stresses were observed for models with minimal cavity design and those with conventional design.