• East Asian mathematical journal
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• 제33권4호
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• pp.353-380
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• 2017

The purpose of this study is to analyze the multiplication units in the elementary school mathematics. In the 2015 revised curriculum, students learn multiplication in $2^{nd}$ grade. The multiplication units is divided into two: multiplication and multiplication facts. In these two units, we mainly analyze situations involving multiplication, models for teaching multiplication, and multiplication strategies for teaching multiplication facts in relation to Subject Matter Knowledge. We called these contents Multiplication Matter Knowledge. We examined the precedent study with regard to multiplication at the elementary mathematics. As results, we prepared an analysis framework for this study. This study was conducted according to qualitative research methods, expecially 'qualitative contents analysis'. The contents here refer to Multiplication Matter Knowledge that can be found in the elementary mathematics textbooks and working books etc. As results of analysis, We can confirm that various multiplication situations and multiplication models are presented in the textbooks. And it has been examined that various multiplication properties are presented in the textbook according to the multiplication strategy levels. We insist elementary school teachers should be aware of these Multiplication Matter Knowledge. This study aims to provide elementary school teachers with basic data in these contexts.

• 한국환경과학회지
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• 제29권5호
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• pp.495-506
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• 2020

This study investigated the nitrate formation process, and mass closure of Particulate Matter (PM) were calculated over the urbanized area of Jeju Island. The data for eight water-soluble inorganic ions and nineteen elements in PM_2.5 and PM₁₀ were used. The results show that the nitrate concentration increased as excess ammonium increased in ammonium-rich samples. Furthermore, nitrate formation was not as important in ammonium-poor samples as it was in previous studies. According to the sum of the measured species, approximately 45~53% of gravimetric mass of PM remained unidentified. To calculate the mass closure for both PM_2.5 and PM₁₀, PM chemical components were categorized into secondary inorganic aerosol, crustal matter, sea salt, trace matter and unidentified matter. The results by the mass reconstruction of PM components show that the portion of unidentified matter was decreased from 52.7% to 44.0% in PM_2.5 and from 45.1% to 29.1% in PM₁₀, despite the exclusion of organic matter and elemental carbon.

• 한국작물학회지
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• 제48권5호
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• pp.376-380
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• 2003

In order to examine the possibility that oil seed rape could be used as a forage fodder crop and to select the most suitable variety of forage rape at the southern area of Korea, two varieties of oil seed rape currently grown for oil production and six introduced varieties of forage rape with relatively high yield and high nutritional value were grown at the same condition their and yield components were observed. Forage rape was superior to oil seed rape in terms of yield components, plant fresh weight and plant dry mater weight. Velox was superior to any other variety of forage rape in these characters. When plant dry matter weight of the rape was subdivided into four components such as a main stem, branch stems, main stem leaves and branch leaves, contribution of these components to plant dry matter weight was in the order of branch stems, branch leaves, the main stem and main stem leaves. Dry matter percentage of the rape ranged from 9.32 to 11.08 percent, which was somewhat low value. There was no significant difference between two groups of the rape in terms of dry matter percentage. Velox showed somewhat higher value in dry matter percentage.

• 방사선산업학회지
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• 제6권1호
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• pp.75-82
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• 2012

Swine wastewater was treated using a unique sequence of ion exchange membrane bed system (IEBR). Organic matter and nutrient in swine wastewater was pre-treated by electron beam irradiation. The optimal dose for solubilization of organic matter in swine wastewater ranged from 20 kGy to 75 kGy. The carbohydrates, proteins, and lipids were investigated as the solubilized organic fraction of swine wastewater and proteins and lipids mainly contained of the solubilized organic matter. The solubilization of organic matter in swine wastewater was affected by the combination effect of temperature and a dose. The average chemical oxygen demand (COD) removal efficiency under room temperature conditions was 67.1%, while that under psychrophilic conditions was 54.6%. For removal of ammonia, the removal efficiency decreased from 63.6% at $23^{\circ}C$ to 33.5% $16.8^{\circ}C$. On the other hand, the removal of phosphorus was not a function of temperature. Struvite was one of main mechanisms in anaerobic condition.

• Human Ecology Research
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• 제57권4호
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• pp.535-544
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• 2019

This study analyzes the need for appropriate response education in schools for national health and sustainable development education in connection with particulate matter, which has recently emerged as a serious environmental and social problem. The survey was conducted on 1,200 teenagers(middle and high school students) in North Jeolla Province. The results of the study are as follows. First, the survey results were generally low in terms of environmental attitude and response(actuality) as well as the level of knowledge of particulate matter. Second, particulate matter-related education is rarely conducted at school sites; therefore, it is also necessary to develop an environmental education programs that can be a significant educational experience along with a specific educational orientation that is required to ensure the achievement of sustainable residential environment education. Finally, we hope that this study will help raise awareness on sustainable residential environment education amid difficulties in accessibility. Issues that need further study include: the absence of education materials, environmental education related to particulate matter, and guidance on how to maintain healthy living for individuals that help increase interest in a sustainable living environment for future generations.

• 한국토양비료학회지
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• 제43권6호
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• pp.1008-1011
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• 2010

A method currently used to determine soil organic matter (SOM), Tyurin method, is time consuming and expensive while accurate. Recently, a spectrophotometric determination was reported to be rapid, accurate, stable, easy to execute, and amendable to field use for soil samples obtained from Texas, USA. The objective of this study was to test if the spectrophotometric method is applicable to soils in Korea. Soil organic matter was extracted by 1 M HCl followed by a 0.25 M NaOH-0.1 M sodium pyrophosphate solution at a ratio of 1:250 soil:extractant. Soil organic matter determined by Tyurin method was linearly related to the value based on absorbance at 300 nm of the soil extracts with a coefficient of determination ($r^2$) of 0.81. Therefore, the result imply that this spectrophotometric method can be used to determine the soil organic matter of agricultural soils in Korea.

• Animal Bioscience
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• 제37권7호
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• pp.1185-1195
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• 2024

Objective: This meta-analysis aimed to evaluate the impact of wilted and unwilted silage on various parameters, such as nutrient content, fermentation quality, bacterial populations, and digestibility. Methods: Thirty-six studies from Scopus were included in the database and analyzed using a random effects model in OpenMEE software. The studies were grouped into two categories: wilting silage (experiment group) and non-wilting silage (control group). Publication bias was assessed using a fail-safe number. Results: The results showed that wilting before ensiling significantly increased the levels of dry matter, water-soluble carbohydrates, neutral detergent fiber, and acid detergent fiber, compared to non-wilting silage (p<0.05). However, wilting significantly decreased dry matter losses, lactic acid, acetic acid, butyric acid, and ammonia levels (p<0.05). The pH, crude protein, and ash contents remained unaffected by the wilting process. Additionally, the meta-analysis revealed no significant differences in bacterial populations, including lactic acid bacteria, yeast, and aerobic bacteria, or in vitro dry matter digestibility between the two groups (p>0.05). Conclusion: Wilting before ensiling significantly improved silage quality by increasing dry matter and water-soluble carbohydrates, as well as reducing dry matter losses, butyric acid, and ammonia. Importantly, wilting did not have a significant impact on pH, crude protein, or in vitro dry matter digestibility.

• Journal of Ecology and Environment
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• 제35권4호
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• pp.259-267
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• 2012

Biomass changes, net primary production and transfer dynamics of dry matter in four subtropical humid montane grasslands at Ebbenadu, Korakundah, Thiashola and Wenlockdown in Nilgiri Biosphere Reserve (NBR), the Western Ghats, India, were investigated. Despite the early report of a higher density and dominance of $C_4$ species over $C_3$ species in these grasslands, no functional study of matter production had previously been carried out. Therefore, in order to determine the roles played by these two groups of species, the present study was attempted. The study revealed that the dry matter and net primary production contributed by $C_4$ species were much greater than those of its $C_3$ counterpart in all the grasslands. The turnover rate of aboveground dry matter for both $C_3$ and $C_4$ species was generally rapid, whereas it was slow for belowground parts, and litter components of $C_3$ and $C_4$ species together. In all grasslands, generally about 60% and 10% of the input were channeled to aboveground and belowground parts, respectively, by the $C_4$ species, whereas the $C_3$ species transferred only about 22% and 8% of dry matter to aboveground and belowground parts, respectively. The total disappearance of dry matter was 2.73, 2.10, 3.19, and $1.96\;g\;m^{-2}\;day^{-1}$ in Ebbenadu, Korakundah, Thiashola and Wenlockdown grasslands, which was 48.83%, 44.30%, 54.81%, and 41.09% of the total input, respectively, in these grasslands. This resulted in a considerable surplus dry matter production in all the grasslands studied. This balance sheet of dry matter in community function indicates that all the four studied grasslands were supporting the existing wild animals adequately in terms of pasture supply. The study further revealed that the stronger establishment of $C_4$ species rather than their $C_3$ counterparts, in terms of higher density and dominance, has driven them to play major roles in matter dynamics and system transfer functions in all the four grasslands studied. This fact evidenced that pasture from $C_4$ species for wild animals was determined to be higher in comparison to that of $C_3$ species.

• 한국조경학회지
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• 제47권6호
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• pp.67-77
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• 2019

본 연구는 미세먼지 문제가 심각한 도심에서 도시근린공원의 중심이 입구에 비해 어느 정도 저감된 공간인지 분석해 보는데 목적이 있다. 또한 공원중앙의 공간 차폐율과 미세먼지 저감율과의 상관관계를 실험을 통해 도출해 내고자 하였다. 대구시 수성구 평지형 도시근린공원 7개를 대상으로 3일동안 같은 장소에서 측정하였다. 연구결과, 첫째, 도시근린공원 중심은 입구보다 온도는 평균 1.05℃ 낮고, 습도는 평균 2.57% 높았다. 둘째, 미세먼지 감소율은 PM1 17.09%, PM2.5 17.65%, PM10 14.99%의 저감율로 초미세먼지가 더 높은 것으로 분석되었으며, 공원의 규모가 작을수록 저감효과가 더 높았다. 또한 기상청발표 미세먼지 농도가 높은날일수록 공원중앙에서의 저감율은 낮았으며, 공원입구의 농도가 높을수록 저감율은 높았다. 셋째, 공원중심에서 공간차폐율이 높을수록 미세먼지 저감효과가 높은 것으로 파악되었다. 도시근린공원의 미세먼지 저감정도와 공간차폐율과의 상관관계를 파악할 수 있었으며, 더 확대된 실험데이터들의 기초가 되기를 기대한다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.184-184
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• 2017

Organic matter is very important and essential factor to maintain productivity of paddy field. But as meat consumption and the demand of grain increase, the demand of forage also increased gradually in Korea. So the amount of organic matter in paddy field have been declined gradually by the reduction of return of rice straw for the forage use for cattle. There is not enough alternative resources for forage, we guess this trend of organic matter decline in paddy field would continue for the time being in Korea. So this study was performed to confirm the variation of organic matter and change of rice yield to select suitable rice cultivars which yield reduction is small in condition of organic matter decrease in paddy field. To confirm the change of rice growth and yield in condition of organic matter decrease in paddy field, we transplanted 10 rice cultivars which yield reduction are small in low fertilizer condition. We transplanted it Buan where double cropping of winter barley continues several years on June 10. Planting density were $70plants/3.3m^2$ Fertilizer amount was $N-P_2O_5-K_2O=9-4.5-5.7kg/10a$ and fertilizer split application of nitrogen was basal-tillering stage-panicle initiation = 50-20-30%. And in the other cultivation management, we observed rice standard culture of NICS. In paddy field where withdraw straws of barley and rice, the organic matter content showed tendency to decrease as the years go on. During rice cultivation season, organic matter decreased little by little, but it increased again after rice harvest season. Rice yield was more in order of Sodami, Chunghaejinmi and Saenuri. We judge that there is an advantage in rice yield of rice cultivars which have later heading date because of suitable ripening temperature. Although Sobibyeo and Shindongjinbyeo showed high yield, head rice yield decreased severely owing to chalky and cracked rice.