• Title/Summary/Keyword: Time difference

Search Result 14,123, Processing Time 0.056 seconds

On Securing Continuity of Long-Term Observational Eddy Flux Data: Field Intercomparison between Open- and Enclosed-Path Gas Analyzers (장기 관측 에디 플럭스 자료의 연속성 확보에 대하여: 개회로 및 봉폐회로 기체분석기의 야외 상호 비교)

  • Kang, Minseok;Kim, Joon;Yang, Hyunyoung;Lim, Jong-Hwan;Chun, Jung-Hwa;Moon, Minkyu
    • Korean Journal of Agricultural and Forest Meteorology
    • /
    • v.21 no.3
    • /
    • pp.135-145
    • /
    • 2019
  • Analysis of a long cycle or a trend of time series data based on a long-term observation would require comparability between data observed in the past and the present. In the present study, we proposed an approach to ensure the compatibility among the instruments used for the long-term observation, which would allow to secure continuity of the data. An open-path gas analyzer (Model LI-7500, LI-COR, Inc., USA) has been used for eddy covariance flux measurement in the Gwangneung deciduous forest for more than 10 years. The open-path gas analyzer was replaced by an enclosed-path gas analyzer (Model EC155, Campbell Scientific, Inc., USA) in July 2015. Before completely replacing the gas analyzer, the carbon dioxide ($CO_2$) and latent heat fluxes were collected using both gas analyzers simultaneously during a five-month period from August to December in 2015. It was found that the $CO_2$ fluxes were not significantly different between the gas analyzers under the condition that the daily mean temperature was higher than $0^{\circ}C$. However, the $CO_2$ flux measured by the open-path gas analyzer was negatively biased (from positive sign, i.e., carbon source, to 0 or negative sign, i.e., carbon neutral or sink) due to the instrument surface heating under the condition that the daily mean temperature was lower than $0^{\circ}C$. Despite applying the frequency response correction associated with tube attenuation of water vapor, the latent heat flux measured by the enclosed-path gas analyzer was on average 9% smaller than that measured by the open-path gas analyzer, which resulted in >20% difference of the sums over the study period. These results indicated that application of the additional air density correction would be needed due to the instrument heat and analysis of the long-term observational flux data would be facilitated by understanding the underestimation tendency of latent heat flux measurements by an enclosed-path gas analyzer.

The Study of Radiation Exposed dose According to 131I Radiation Isotope Therapy (131I 방사성 동위원소 치료에 따른 피폭 선량 연구)

  • Chang, Boseok;Yu, Seung-Man
    • Journal of the Korean Society of Radiology
    • /
    • v.13 no.4
    • /
    • pp.653-659
    • /
    • 2019
  • The purpose of this study is to measure the (air dose rate of radiation dose) the discharged patient who was administrated high dose $^{131}I$ treatment, and to predict exposure radiation dose in public person. The dosimetric evaluation was performed according to the distance and angle using three copper rings in 30 patients who were treated with over 200mCi high dose Iodine therapy. The two observer were measured using a GM surverymeter with 8 point azimuth angle and three difference distance 50, 100, 150cm for precise radion dose measurement. We set up three predictive simulations to calculate the exposure dose based on this data. The most highest radiation dose rate was showed measuring angle $0^{\circ}$ at the height of 1m. The each distance average dose rate was used the azimuth angle average value of radiation dose rate. The maximum values of the external radiation dose rate depending on the distance were $214{\pm}16.5$, $59{\pm}9.1$ and $38{\pm}5.8{\mu}Sv/h$ at 50, 100, 150cm, respectively. If high dose Iodine treatment patient moves 5 hours using public transportation, an unspecified person in a side seat at 50cm is exposed 1.14 mSv radiation dose. A person who cares for 4days at a distance of 1 meter from a patient wearing a urine bag receives a maximum radiation dose of 6.5mSv. The maximum dose of radiation that a guardian can receive is 1.08mSv at a distance of 1.5m for 7days. The annual radiation dose limit is exceeded in a short time when applied the our developed radiation dose predictive modeling on the general public person who was around the patients with Iodine therapy. This study can be helpful in suggesting a reasonable guideline of the general public person protection system after discharge of high dose Iodine administered patients.

The Effects of Experimental Warming on Seed Germination and Growth of Two Oak Species (Quercus mongolica and Q. serrata) (온난화 처리가 신갈나무(Quercus mongolica)와 졸참나무(Q. serrate)의 종자발아와 생장에 미치는 영향)

  • Park, Sung-ae;Kim, Taekyu;Shim, Kyuyoung;Kong, Hak-Yang;Yang, Byeong-Gug;Suh, Sanguk;Lee, Chang Seok
    • Korean Journal of Ecology and Environment
    • /
    • v.52 no.3
    • /
    • pp.210-220
    • /
    • 2019
  • Population growth and the increase of energy consumption due to civilization caused global warming. Temperature on the Earth rose about $0.7^{\circ}C$ for the last 100 years, the rate is accelerated since 2000. Temperature is a factor, which determines physiological action, growth and development, survival, etc. of the plant together with light intensity and precipitation. Therefore, it is expected that global warming would affect broadly geographic distribution of the plant as well as structure and function ecosystem. In order to understand the effect of global warming on the ecosystem, a study about the effect of temperature rise on germination and growth in the plant is required necessarily. This study was carried out to investigate the effects of experimental warming on the germination and growth of two oak species(Quercus mongolica and Q. serrata) in temperature gradient chamber(TGC). This study was conducted in control, medium warming treatment($+1.7^{\circ}C$; Tm), and high warming treatment ($+3.2^{\circ}C$; Th) conditions. The final germination percentage, mean germination time and germination rate of two oak species increased by the warming treatment, and the increase in Q. serrata was higher than that in Q. mongolica. Root collar diameter, seedling height, leaf dry weight, stem dry weight, root dry weight, and total biomass were the highest in Tm treatment. Butthey were not significantly different in the Th treatment. In the Th treatment, Q. serrata had significantly higher H/D ratio, S/R ratio, and low root mass ratio (RMR) compared with control plot. Q. mongolica had lower RMR and higher S/R ratio in the Tm and Th treatments compared with control plot. Therefore, growth of Q. mongolica are expected to be more vulnerable to warming than that of Q. serrata. The main findings of this study, species-specific responses to experimental warming, could be applied to predict ecosystem changes from global warming. From the result of this study, we could deduce that temperature rise would increase germination of Q. serrata and Q. mongolica and consequently contribute to increase establishment rate in the early growth stage of the plants. But we have to consider diverse variables to understand properly the effects that global warming influences germination in natural condition. Treatment of global warming in the medium level increased the growth and the biomass of both Q. serrata and Q. mongolica. But the result of treatment in the high level showed different aspects. In particular, Q. mongolica, which grows in cooler zones of higher elevation on mountains or northward in latitude, responded more sensitively. Synthesized the results mentioned above, continuous global warming would function in stable establishment of both plants unfavorably. Compared the responses of both sample plants on temperature rise, Q. serrata increased germination rate more than Q. mongolica and Q. mongolica responded more sensitively than Q. serrata in biomass allocation with the increase of temperature. It was estimated that these results would due to a difference of microclimate originated from the spatial distribution of both plants.

A Study on changes in Hitting-pressing forms of flat plate in Gyeongju area -Short beating, Medium beating plate, long beating plate and Stamped-roof tile- (경주지역 평기와의 타날형태 변화에 대한 검토 -단판·중판·인장 그리고 장판으로-)

  • Cha, Soon-chul
    • Korean Journal of Heritage: History & Science
    • /
    • v.40
    • /
    • pp.73-104
    • /
    • 2007
  • Centering around ruins recognized of being relatively early stage related to flat tile and brick, excavated in Silla capital area, the study attempted elementary approach to seek the appearance time of every remain through comparing them from the excavated cases and production methods of Short beating, Medium beating plate, Long beating plate and Stamped-roof tile. Gyeongju began to use the short beating plate made of tile-less plates or tile plate and increased its quantity. That is deemed to be due to efficiency of beating plate making methods, and moreover to be limited only for use in the palace castle and offices. That is, making short beating plates is presumed to be made merely under some definite objectives. Medium beating plate has been spread to the whole country since Silla and Baekje united. Differently from Koguryo and Baekje, Silla had its unique Beating-plates making technology available for mass-production, which was spread to the whole country and resulted in disappearing of Koguryo and Baekje technology. Long beating plate was not nearly founded in Gyeongju area, but flat tile and common tile excavated in Sachunwang Temple site and Samrang Temple 3rd remains are known. In the outskirts of Gyeongju, long beating plate appeared between the latter half of 8C and the beginning of 9C. Until now, different views have raised to appearance of long beating plate of Unified Silla, which is expected to be clarified under the situation excavated by position relations. Stamped-roof title in Gyeongju is estimated as used after the datum point year 679. While in Baekje area, five stems and branches were involved, in Silla area, code or sign was shown much. The difference between two areas would be due to each other factory, and especially the marked contents werenot letters, which means it had been changed from Baekje s existing-methods. That is, it says the production environment changed owing to Silla's merging. And stamped-roof tile was temporarily used in Gyeongju but soon disappeared, which was because Silla beating plates made under cylinder-shaped tile barrel(圓筒瓦桶) and hitting-pressing of Medium beating plate had beenspread to the whole country, so the production technology of Koguryo and Baekje was naturally dismissed. In consequence, the mergence by Silla brought about unification of each nation's special technology.

Effect of polishing methods on color change by water absorption in several composite resins (여러 복합레진에서 수분 흡수에 의한 색변화에 연마가 미치는 영향)

  • Kim, Hye Jin;Kim, Mi-yeon;Song, Byung-chul;Kim, Sun-ho;Kim, Jeong-hee
    • Journal of Dental Rehabilitation and Applied Science
    • /
    • v.35 no.1
    • /
    • pp.1-10
    • /
    • 2019
  • Purpose: The aim of this study was to evaluate the influence of polishing methods on the color stability of composite resins. Materials and Methods: Two bulk-fill and four conventional resin composites were filled in cylindrical molds (6 mm diameter, 4 mm height) and light-cured. The specimens were stored in $34^{\circ}C$ distilled water for 24 h. Spectrophotometer was used to determine the color value according to the CIE $L^*a^*b^*$ color space. Each group was divided into three groups according to polishing methods (n = 5). Group 1 was control group (Mylar strip group), group 2 was polished with PoGo, and group 3 was polished with Sof-Lex Spiral wheels. Color evaluation was performed weekly for 4 weeks after immersion in $34^{\circ}C$ distilled water. The results were analyzed by generalized least squares method (P < 0.05). Results: Generalized least squares analysis revealed that Sof-Lex Spiral wheels group showed the significantly lower ${\Delta}E$ values compared to PoGo and control group (P < 0.05). The ${\Delta}E$ values of polished group showed the significantly lower than the ${\Delta}E$ values of unpolished group (P < 0.05). Regarding color changes of composite resins, there was no significant difference between the ${\Delta}E$ values of Filtek Z250 and Filtek Z350 XT Universal restorative in all time intervals (P < 0.05). Tetric N-Ceram Bulk Fill showed the significantly lower ${\Delta}E$ values compared to other composite resins in 1, 2, 3 weeks (P < 0.05). Conclusion: Within the limitations of this study, polishing methods influence the color stabilities of composite resins. The group polished with Sof-Lex Spiral Wheels showed more resistance to discoloration than group polished with PoGo.

Historical Observation and the Characteristics of the Records and Archives Management in Korea (한국 기록관리의 사적 고찰과 그 특징)

  • Lee, Young-Hak
    • The Korean Journal of Archival Studies
    • /
    • no.34
    • /
    • pp.221-250
    • /
    • 2012
  • This paper introduces the characteristics of the records and archives management of Korea from Joseon dynasty to now. This paper also explains historical background of making the records and archives management in Joseon dynasty. This paper introduces the process of establishment of modern records management system by adopting records management system and public administration of USA after liberation in 1945. The Joseon bureaucrats established systematic methodologies for managing and arranging the records. Jeseon dynasty managed its records systematically since it was a bureaucratic regime. It is also noticeable that the famous Joseonwangjosilrok(Annals of Joseon dynasty) came out of the power struggles for the control of the national affairs between the king and the nobility during the time of establishment of the dynasty. Another noticeable feature of the records tradition in Joseon dynasty was that the nobility recorded their experience and allowed future generations use and refer their experiences and examples when they performed similar business. The records of Joseon period are the historical records which recorded contemporary incidents and the compilers expected the future historians evaluate the incidents they recorded. In 1894, the reformation policy of Gaboh governments changed society into modernity. The policy of Gaboh governments prescribed archive management process through 'Regulation(命令頒布式)'. They revised the form of official documents entirely. They changed a name of an era from Chinese to unique style of Korean, and changed original Chinese into Korean or Korean-Chinese together. Also, instead of a blank sheet of paper they used printed paper to print the name of each office. Korea was liberated from Japanese Imperialism in 1945 and the government of Republic of Korea was established in 1948. In 1950s Republic of Korea used the records management system of the Government-General of Joseon without any alteration. In the late of 1950's Republic of Korea constructed the new records management system by adopting records management system and public administration of USA. However, understanding of records management was scarce, so records and archives management was not accomplished. Consequently, many important records like presidential archives were deserted or destroyed. A period that made the biggest difference on National Records Management System was from 1999 when was enacted. Especially, it was the period of President Roh's five-year tenure called Participation Government (2003-2008). The first distinctive characteristic of Participation Government's records management is that it implemented governance actively. Another remarkable feature is a nomination of records management specialists at public institutions. The Participation Government also legislated (completely revised) . It led to a beginning of developing records management in Republic of Korea.

Characteristics of Inclusive Playground Guidelines (통합놀이터 가이드라인의 특성)

  • Kim, Yun-Geum;Kim, Hana;Maeng, Soo-hyun
    • Journal of the Korean Institute of Landscape Architecture
    • /
    • v.46 no.6
    • /
    • pp.75-84
    • /
    • 2018
  • The inclusive playground is a playground where disabled children and non-disabled children can play together, not a playground for the disabled. It started with the change of social awareness of the citizenship rights of disabled people in the 1960s and the resulting playgrounds. Since then, inclusive playgrounds have been developed in many countries, and these are organized in the form by guidelines. In Korea, social interest in inclusive playgrounds is increasing, but there are no systematic guidelines in Korea, and the application of overseas cases or guidelines is limited. The purpose of this study is to classify the concept of inclusive playgrounds and design guidelines, that were previously presented in inclusive playground design guideline of various countries and analyze the characteristics of, design scope, and design principles, and provide a basic framework for creating guidelines. The purpose of the design guideline was to present specific numerical values to the inclusive playground design guidelines, to link with academic research and industrial products, to present pursuit values, and to expand the value of pursuing design methods. The contents were covered by scope, conceptualization, principles of design and design process, design guidelines, and checklists. Most of the guideline covers specific autonomous governments or countries that can apply the related systems or laws, but the composition of the detailed contents is different. The guiding value of inclusive playgrounds presented in each guideline is not a playground for the disabled but a playground for all, and some guidelines refer to the difficulty in playgrounds considering non-disabled children. Based on these concepts, design guidelines are presented in each guideline. Improving the accessibility in design principles is a common theme and adds to the principles of safety, independence, convenience, and playability. None of the guidelines do not provide design guidelines. Although there is a difference in the degree and method of specificity provided by each of the guidelines, the design guidelines can be generally summarized as space, copper line, and unit facilities. As mentioned in many guidelines, an inclusive playground is not only a playground for children with disabilities. Therefore, in the design guidelines, it is also important to the support play of children with disabilities and to induce inclusive play. The design guidelines presented in the guideline can be rearranged into three stages of 'supporting the play of children with disabilities', 'securing the dimensions and materials of spaces and facilities', 'adding auxiliary devices' and 'designing new facilities'. There are three design guidelines for inducing inclusive play. First, by creating various difficulty levels and intersecting spaces, children with various abilities can play with each other, and at the same time, they can interact witheach other. Second, all children can cooperate and play without distinction between children with disabilities and non-disabled children. Finally, the guardian provides the conditions for efficient support so that the disabled child can fully enjoy the inclusive playground.

Effectiveness Evalution of 18F-FDG Auto Dispenser (RIID: Radiopharmaceutical Intelligent Dispenser) (18F-FDG 자동분주기 사용에 따른 유용성 평가)

  • Yoo, Moon-Gon;Moon, Jae-Seung;Kim, Su-Geun;Shin, Min-Yong;Kim, Seung-Chul;Lee, Tea-hun;An, Sung-Hyeun
    • The Korean Journal of Nuclear Medicine Technology
    • /
    • v.22 no.2
    • /
    • pp.79-83
    • /
    • 2018
  • Purpose $^{18}F-FDG$, which is commonly used in PET-CT examinations, is low in capacity and it is difficult to keep the amount of radioactivity busy when the specific activity is high, increasing the amount of space dose and radioactive contamination in the distribution room. Therefore, while evaluating the actual dose administered to patients during the manual dispense process, the medical institution intends to assess the usefulness of the auto dispenser by comparing the differences from the actual dose administered to the patient using the new automatic dispense. Materials and Methods From July 2016 to December 2016, 846 patients were manually administered by workers using $^{18}F-FDG$ and $^{18}F-FDG$ 906 patients were using auto dispenser from July 2017 to December 2017. Results Capacity administered to patients during the manual dispense averaged $35.41{\pm}27.79%$ compared to the recommended dose, and the auto dispenser process showed a small difference of $-2.15{\pm}3.99%$ compared to the recommended dose(p<0.05). Conclusion Working people did not have to touch radioactive medicines directly while they were busy in the auto dispenser, and because of the availability of other tasks far away, the time and distance to receive the exposure were also advantageous. It is believed that future use by many medical institutions will not only reduce the dose to patients but also help reduce the exposure dose to workers.

The Far-infrared Drying Characteristics of Steamed Sweet Potato (증자 호박고구마의 원적외선 건조특성)

  • Lee, Dong Il;Lee, Jung Hyun;Cho, Byeong Hyo;Lee, Hee Sook;Han, Chung Su
    • Food Engineering Progress
    • /
    • v.21 no.1
    • /
    • pp.42-48
    • /
    • 2017
  • The purpose of this study was to verify the drying characteristics of steamed sweet potato and to establish optimal drying conditions for far-infrared drying of steamed sweet potato. 4 kg of steamed sweet potato was sliced to thicknesses of 8 and 10 mm, and dried by a far-infrared dryer until a final moisture content of $25{\pm}0.5%$. The far-infrared dryer conditions were an air velocity of 0.6, 0.8 m/s and drying temperature of 60, 70, and $80^{\circ}C$. The results can be summarized as follows. The drying time tended to be reduced as temperature and air velocity for drying increased. The Lewis and Modified Wang and Singh models were found to be suitable for drying of steamed sweet potato by a far-infrared dryer. The color difference was 35.09 on the following conditions: Thickness of 8 mm, temperature of $80^{\circ}C$, and air velocity of 0.8 m/s. The highest sugar content ($59.11^{\circ}Brix$) was observed on the conditions of a thickness of 8 mm, temperature of 80, and air velocity of 0.8 m/s. Energy consumption decreased on the conditions of higher temperature, slower air velocity, and thinner steamed sweet potato.

Meal kit purchasing behavior and relationship with the nutrition quotient of young adults in Chungnam (충남 일부지역 젊은 성인의 밀키트 구매행태 및 영양지수와의 관련성)

  • Lee, Eun-Young;Kim, Yu-Mi;Choi, Mi-Kyeong
    • Journal of Nutrition and Health
    • /
    • v.54 no.5
    • /
    • pp.534-546
    • /
    • 2021
  • Purpose: This study aimed at understanding meal kit purchasing behavior and investigating its relationship with the Nutrition Quotient (NQ) of young adults. Methods: We conducted a survey on adults in their 20s and 30s covering their meal kit purchase experience, satisfaction, recognition, and purchase intention, and examined the relationship between the meal kit purchase and their NQ from February to March 2021. Results: Among the 404 subjects, 37.9% of males and 48.0% of females had experience in purchasing a meal kit (p < 0.001). The highest response indicated that the purchase cost of meal kits was 10,000-20,000 Won at a time, and the frequency of purchase was less than once a month. The convenience of cooking was the main reason for the purchase of meal kits, which were consumed mainly in the evening with family. The satisfaction with the purchase experience of a meal kit was rated 3.6 points for males and 3.7 points for females out of 5 points, and the satisfaction experienced by women was significantly higher than men in terms of freshness of ingredients, packaging design, and adequacy of the quantity of content (p < 0.05). Recognition of the meal kit was rated 3.5 points for males and 3.7 points for females out of 5 points. The purchase intention of the meal kit was rated 3.8 points for those with prior purchase experience, 3.2 points for the non-experienced, 3.3 points for males, and 3.6 points for females out of 5 points each (p < 0.001). The NQ score of dietary behavior in females with experience of meal kit purchases was significantly higher than non-experience (p < 0.05). Conclusions: The dietary behavior of female showed a significant difference by the meal kit purchase experience. It is necessary to understand the consumers' meal kit purchasing behavior to enable the development of various health-oriented meal kit products.