• The Mathematical Education
• /
• v.57 no.2
• /
• pp.93-110
• /
• 2018

One of the biggest changes in the 2015 revised mathematics curriculum is shifting to the second year of middle school in Pythagorean theorem. In this study, the following subjects were studied. First, Pythagoras theorem analyzed the expected problems caused by the shift to the second year middle school. Secondly, we have researched the reconstruction method to solve these problems. The results of this study are as follows. First, there are many different ways to deal with Pythagorean theorem in many countries around the world. In most countries, it was dealt with in 7th grade, but Japan was dealing with 9th grade, and the United States was dealing with 7th, 8th and 9th grade. Second, we derived meaningful implications for the curriculum of Korea from various cases of various countries. The first implication is that the Pythagorean theorem is a content element that can be learned anywhere in the 7th, 8th, and 9th grade. Second, there is one prerequisite before learning Pythagorean theorem, which is learning about the square root. Third, the square roots must be learned before learning Pythagorean theorem. Optimal positions are to be placed in the eighth grade 'rational and cyclic minority' unit. Third, Pythagorean theorem itself is important, but its use is more important. The achievement criteria for the use of Pythagorean theorem should not be erased. In the 9th grade 'Numbers and Calculations' unit, after learning arithmetic calculations including square roots, we propose to reconstruct the square root and the utilization subfields of Pythagorean theorem.

• Journal of Life Science
• /
• v.11 no.6
• /
• pp.509-516
• /
• 2001

Enzymes and non-enzymatic antioxidants are involved in defense of oxgen free radical intermediates in all aerobic cells. The non -enzymatic antioxidants and antioxidant enzyme from the extracts of Solanum nigrum L. known to be anticancer medicinal plant were examined in other to utilize the discovery in natural products as cancer chem-opereventive agents. The DPPH(1,1-diphenyl-2-picryl-hydrazyl) free radical scavening activity on plant position of Solanum nigrum L. was the highest in root, with stem, whole plant, seed, leaf and flower, at higher activities respectively. In extraction methods, the DPPH free radical scavenging activity by circulating extraction with 80 % MeOH. The DPPH activity of L6 fraction by LH-20 column chromatography showed about 6.7 times higher than that of ethyl acetate-fraction. These were identified as phenolic compounds such as 2-6-methano-3-benzazocin-11-ol, 2[1H]-phyidinethione and 2-hydroxy -5-methyl-benzaldehyde. Peroxidase(POD) and superoxide dismutase(SOD) activities of stem and root were higher than that of other plant positions and those of plant positions according to growing stage were the highest in 60 days after seeding. The numbers of isozyme pattern of POD and SOD showed 10 hands and 5 bands, respectively, especially, 8 bands of POD and 3 bands of SOC showed a difference according to plant positions.

• The Plant Pathology Journal
• /
• v.29 no.3
• /
• pp.242-248
• /
• 2013

In the Northeast of Brazil, expansion of guava crops has been impaired by Meloidogyne enterolobii that causes root galls, leaf fall and plant death. Considering the fact that arbuscular mycorrhizal Fungi (AMF) improve plant growth giving protection against damages by plant pathogens, this work was carried out to select AMF efficient to increase production of guava seedlings and their tolerance to M. enterolobii. Seedlings of guava were inoculated with 200 spores of Gigaspora albida, Glomus etunicatum or Acaulospora longula and 55 days later with 4,000 eggs of M. enterolobii. The interactions between the AMF and M. enterolobii were assessed by measuring leaf number, aerial dry biomass, $CO_2$ evolution and arbuscular and total mycorrhizal colonization. In general, plant growth was improved by the treatments with A. longula or with G. albida. The presence of the nematode decreased arbuscular colonization and increased general enzymatic activity. Higher dehydrogenase activity occurred with the A. longula treatment and $CO_2$ evolution was higher in the control with the nematode. More spores and higher production of glomalin-related soil proteins were observed in the treatment with G. albida. The numbers of galls, egg masses and eggs were reduced in the presence of A. longula. Inoculation with this fungus benefitted plant growth and decreased nematode reproduction.

• Explosives and Blasting
• /
• v.9 no.4
• /
• pp.3-12
• /
• 1991

The cautious blasting works had been used with emulsion explosion electric M /S delay caps. Drill depth was from 3m to 6m with Crawler Drill 70mm on the calcalious sand stone (soft-moderate-semi hard Rock) . The total numbers of feet blast were 88. Scale distance were induces 15.52-60.32. It was applied to Propagation Law in blasting vibration as follows .Propagtion Law in Blasting Vibration V=k(D/W/sup b/)/sup n/ where V : Peak partical velocity(cm/sec) D : Distance between explosion and recording sites(m) W ; Maximum Charge per delay -period of eight milliseconds or more(Kg) K : Ground transmission constant, empirically determind on the Rocks, Explosive and drilling pattern ets. b : Charge exponents n : Reduced exponents Where the quantity D/W/sup b/ is known as the Scale distance. Above equation is worked by the U.S Bureau of Mines to determine peak particle velocity. The propagation Law can be catagrorized in three groups. Cabic root Scaling charge per delay Square root Scaling of charge per delay Site-specific Scaling of charge delay Charge and reduction exponents carried out by multiple regressional analysis. It's divided into under loom and over loom distance because the frequency is varified by the distance from blast site. Empirical equation of cautious blasting vibration is as follows. Over 30m--under 100m----V=41(D/ W)/sup -1.41/-----A Over l00m---------V=121(D/ W)/sup -1.56/-----B K value on the above equation has to be more specified for furthur understand about the effect of explosives. Rock strength, And Drilling pattern on the vibration levels, it is necessary to carry out more tests.

• Asian Journal of Turfgrass Science
• /
• v.1 no.1
• /
• pp.18-29
• /
• 1987

This study was carried out to examine the effect of nitrogen application and clipping interval on the characteristics of several turf components of korean lawngrass for the basic data of lawn management. It was treated by Split plot design with three replications. The main plots were nitrogen levels with 0, 350, and 700kgN / ha, and the sub plots were clipping intervals with 10, 20, and 30 days The results obtained are summarized as follows ; 1. Increasing the rate of nitrogen fertilizer and frequent clipping increased tiller number of korean lawngrass and the maximum number of tillers obtained in October were recorded from 700kgN application and clipping treatment of 10 days interval. Meanwhile, treatment of 350kgN with 10 days clipping interval increased tillers much more than those of 700kgN with 20 and 30 days clipping intervals. 2. The average number of green leaves occurred during the growth period maximized by applying 700 kgN and clipping 10 days interval. 3. Increasing tiller numbers significantly decreased tops DM weight per tiller by clippng plants at interval of 10 and 20 days, irrespective of nitrogen applied, and with nil N, at the interval of 30 days. By applying 700kgN however, tops DM weight per tiller increased as the number of tillers increased consistently. 4. The highest tops DM weight was achieved from late August to early September by applying 350 and 700kgN. 5. During the growth period, nitrogen application increased unders(stolon+root) DM weight, and, at the same level of nitrogen applied, the increase in stolon DM weight enhanced by lengthening the clipping interval to 30 days. 6. Nitrogen efficiency to green leaves, stolon nodes and DM weight of root with high nitrogen was achieved as clipping interval was shortened.

• Korean journal of food and cookery science
• /
• v.19 no.5
• /
• pp.562-570
• /
• 2003

The awareness of ritual foods in general rituals were surveyed and compared in the Gyeonggi and Gyungsangbuk-do areas in order to identify the characteristics of Korean rituals and establish desirable ritual foods. As materials for "Jeon" (fried pan cakes) in rituals, fish fillets, meat and vegetables were largely used in the Gyeonggi region. In the Gyeongbuk region, all three of these ingredients were the most highly used for "Jeon" also. In the case of rice cakes, "Songpyun" steamed on a layer of pine needles, "Jeolpyun" and "Sirudduk", with a red beans, were mostly used in Gyeonggi-do, while "Songpyun", "Jeolpyun" and "Ingelmi" were largely used in Gyeongsangbuk-do. As seasoned vegetables and herbs, fernbrakes, root of bell flowers, green bean sprouts and bean sprouts were largely used in Gyeonggi-do region, whereas, fernbrakes, bean sprouts, root of bell flowers and spinaches were mainly used in Gyeongbuk region. The use of fernbrakes was highest in both regions. With regard to the number of side dishes, 2∼3 kinds of seasoned herbs and 3∼4 kinds of fruits were mostly used, but with slightly higher numbers in the Gyeongsangbuk-do than the Gyeonggi-do region. With regard to liquor used for rituals, clear strained rice wine was used most in the Gyeonggi-do area, while more unrefined rice wine was used in the Gyeongbuk region. Meat was the most used ingredient in broth slices of dried meat and cod were highly used in the Gyeonggi region, but slices of dried squid were most widely used in the Gyeongbuk region. Most households in both regions tended not to use raw fish in the rituals, and as for the ingredients of Korean Kabobs, meat was the most widely used, then fish and finally vegetables were the most used ingredients. Beef soup was the most used, but more green vegetable soup was used in the Gyeongbuk than the Gyeonggi region. Sweet drink made from fermented rice (sikhe) was generally used in the rituals. It was the most widely used in the Chusok-Hangawi Ritual in the Gyeonggi region, while it was used in the New Year's Ritual in the Gyeongbuk region.

• Korean Journal of Agricultural Science
• /
• v.49 no.4
• /
• pp.749-758
• /
• 2022

The effect of varied light intensities on the growth of daughter plants during propagation and after transplant to raised beds were examined in 'Sulhyang' strawberry. To this end, four treatments in controlling solar radiation inside a plastic house were made: 55% retractable shading and 35, 55, and 75% fixed shading. The plastic house was shaded only from 11:00 to 16:00 in June and 10:00 to 16:00 in July to September for the treatment of 55% retractable shading. The mean solar radiation inside the plastic house in the retractable 55% shading treatment was 317 W·m^-2 and those in the 35, 55, and 75% fixed shading treatments were 183, 165, and 116 W·m^-2, respectively, at 10 o'clock in the morning. The 55% and 75% fixed shading resulted in taller daughter plants with wider leaf areas than 55% retractable shading. The retractable shading also showed higher leaf numbers, crown diameters, root weights, and fresh weights compared to fixed shading treatments. Regarding the inorganic element contents, daughter plants grown under 75% fixed shading had 1.35% total nitrogen content followed by 1.19% in 35% fixed shading, 1.14% in 55% fixed shading, 1.14% in open culture, and 1.10% in 55% fixed shading. After 54 days following the transplant of daughter plants to a raised bed, the fresh weight of the aboveground part was the heaviest in the 55% retractable shading and non-shading treatments. The 75% fixed shading treatment had the lowest fresh weight of the aboveground plant parts. The results of this study could be used for the production of high-quality daughter strawberry plants.

• Horticultural Science & Technology
• /
• v.33 no.4
• /
• pp.518-524
• /
• 2015

The objective of this research was to investigate the influence of various depths of expanded rice hull (ERH) medium and fixation dates of runner plantlets of 'Seolhyang' strawberry on the growths in nursery field and in plastic house soil after transplanting. The five treatments in medium depths (30, 50, 70, 90, and 110 mm) and four treatments in fixation dates (1st and 15th July and 1st and 15th August) were tested. The growths of runner plantlets were investigated before transplanting to plastic house soil. The early growth and inflorescence rates of crops after transplant to plastic house soil were also investigated. The plant height and fresh weight of runner plantlets were the highest in the medium depths of 50, 70, and 90 mm. The medium depth of 30 mm had higher numbers of first roots, but lower root fresh weight compared to those of 70, 90, and 110 mm. The treatment of 30 mm in medium depth showed poorer growth in all indexes except root length and root weight compared to those of 70, 90, and 110 mm. The runner plantlets fixed on July 1 and July 15 showed good root growth and the weights of ERH adhered to form root balls were 18.3 g and 13.9 g, respectively. The detached amount of ERH was less than 40% in the two treatments when root balls were shaken by a vibratory sieve shaker. The plant growth at 45 days after transplanting to plastic house soil were not significantly different when the runner plantlets were fixed in the period from July 1 to Aug. 1. The inflorescence rates of the first cluster were 93 to 100% when runner plantlets were fixed in the period from July 1 to Aug. 1. By contrast the runner plantlets fixed on the Aug. 15 had a 67% in florescence rate for the first cluster. These results indicate that optimum depth of ERH medium was 7 cm and the ranges of optimum fixation dates are from July 20 to 25.

• The Korean Journal of Mycology
• /
• v.13 no.1
• /
• pp.41-47
• /
• 1985

Eighteen plant residues were added to soil and the amended soil was inoculated with chlamydospores (5,000 cells/g soil) of Fusarium solani causing root rot of ginseng in soil to test the effects of amendment using pea (Pisium sativa L.) as an index plant. Distributional conditions of microogranisms in soil were compared with each other before and after dealing with soil amendment by plant debries. Infection rate by index plant's infectivity showed a higher degree in the treatment of wheat crushed than in control group, and followed by stalk of sweet potato, chinese cabbage, ginseng leaves and soybean pod. On the other hand, the de­creasing order of infection rate was root of garlic, welsh onion, cabbage leaf and stalk, green onion stalk, wheat straw and barley straw. In comparison with control group, the propagules of fungi increased in the treatment of ginseng leaves, soybean ground, wheat crushed, maize stalk, and chinese cabbage, but decreased in the root of garlic, cabbage, and barley straw. Population of total bacteria increased in the treatment of soybean ground, chinese cabbage, radish stalk, welsh onion, and wheat crushed, but decreased in barley straw, tobaco root, ginseng stalk, and wheat straw. The numbers of actinomycetes increased only in the treatment of soybean ground in a comparison with control and also decreased in the garlic stalk and tobaco root. The propagules of Fusarium spp increased in the treatment of chinese cabbage, welsh onion, radish stalk, wheat crushed, and sweet potato stalk, wheat crushed, and sweet potato stalk, but decreased in the treat­ment of wheat straw, ginseng leaves, and cabbage than control.

• The KIPS Transactions:PartA
• /
• v.12A no.5 s.95
• /
• pp.413-420
• /
• 2005

The Newton-Raphson iterative algorithm for finding a floating point reciprocal square mot calculates it by performing a fixed number of multiplications. In this paper, a variable latency Newton-Raphson's reciprocal square root algorithm is proposed that performs multiplications a variable number of times until the error becomes smaller than a given value. To find the rediprocal square root of a floating point number F, the algorithm repeats the following operations: '$X_{i+1}=\frac{{X_i}(3-e_r-{FX_i}^2)}{2}$, $i\in{0,1,2,{\ldots}n-1}$' with the initial value is '$X_0=\frac{1}{\sqrt{F}}{\pm}e_0$'. The bits to the right of p fractional bits in intermediate multiplication results are truncated and this truncation error is less than '$e_r=2^{-p}$'. The value of p is 28 for the single precision floating point, and 58 for the double precision floating point. Let '$X_i=\frac{1}{\sqrt{F}}{\pm}e_i$, there is '$X_{i+1}=\frac{1}{\sqrt{F}}-e_{i+1}$, where '$e_{i+1}{<}\frac{3{\sqrt{F}}{{e_i}^2}}{2}{\mp}\frac{{Fe_i}^3}{2}+2e_r$'. If '$|\frac{\sqrt{3-e_r-{FX_i}^2}}{2}-1|<2^{\frac{\sqrt{-p}{2}}}$' is true, '$e_{i+1}<8e_r$' is less than the smallest number which is representable by floating point number. So, $X_{i+1}$ is approximate to '$\frac{1}{\sqrt{F}}$. Since the number of multiplications performed by the proposed algorithm is dependent on the input values, the average number of multiplications Per an operation is derived from many reciprocal square root tables ($X_0=\frac{1}{\sqrt{F}}{\pm}e_0$) with varying sizes. The superiority of this algorithm is proved by comparing this average number with the fixed number of multiplications of the conventional algorithm. Since the proposed algorithm only performs the multiplications until the error gets smaller than a given value, it can be used to improve the performance of a reciprocal square root unit. Also, it can be used to construct optimized approximate reciprocal square root tables. The results of this paper can be applied to many areas that utilize floating point numbers, such as digital signal processing, computer graphics, multimedia, scientific computing, etc.