• Journal of The Korean Association For Science Education
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• 제29권8호
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• pp.923-933
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• 2009

In this study, analysis was carried out on science experiment in high school textbooks, illustrating 'the effect of pH on enzyme activity.' Five of the total 16 science textbooks introduced in this experiment, and the experimental conditions therein were analyzed. Textbook analysis revealed that pH of below 3 was used for 'acidic condition' and that of over 11 was used for 'basic' condition. Using the experimental conditions described in the textbooks, review experiments were performed. Buffering effect with the addition of saliva was found in the pH region around 7 when buffer solution was not used to control pH as was in the textbooks. The enzyme activity experiments were performed controlling pH from pH 2 to 13 with buffer. The color of the sample was blue from pH 2 to 4, and then disappeared from pH 5 to 8, reflecting that starch was digested owing to enzyme activity. In pH 9 light blue color appeared, indicating de-activation of enzyme under this basic condition. However, the blue color of the sample became lighter at pH 10 and disappeared from pH 11, which was different from the expected behavior anticipating dark blue color due to de-activation of enzyme under strong basic condition. These results can wrongly influence students to interpret that enzyme can be activated in this pH condition. So, we analyzed the reason for the color of the sample turning light blue in pH 10 and disappeared from pH 11. The analysis resulted that ${I_3}^-$ and/or ${I_5}^-$ subunits of polyiodides within the starch helix in starch-iodine complex, showing blue, decreases above pH 10 due to disproportionation to HOI, ${IO_3}^-$, and $I^-$ by the reaction with $OH^-$.

• Journal of Korean Society of Forest Science
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• 제45권1호
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• pp.26-36
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• 1979

Through several trials that has done for making the fertilizing-counter plan on the soil improving species, some results have been got as follows; 1. In the non-phosphorus dressing plots soil improving species have very poor survial ratio and show us to be died step by step. It may be resons that root can not make the nodule in case of non-phosphorus dressing and so tree could not absorb the nitrogen nutrient fixed by the nodule. And root competition with the weedy speces for utilizing the nutrient and oxygen in the soil could be reasons when planting in the heavy weedy rooting site. 2. Triple super phosphate, Fused Mg Phosphate and Fused super phosphate have showed the remarkable effects on the growth of soil improving species within 3rd year after planting. But Koreaan tablet fertilizer(9-12-4) for forest purpose have reacted considerably lower effect in comparision with the above powder and grain type phosphorous fertilizer. 3. In case of tablet type fertilizer tree root will have very little phosphorus absorbing surface because phosphorus can be utilized only from the tablet surface and root can not penetrate into the tablet. This my be reson to show the poor dressing reaction of tablet fertilizer but tablet fertilizer has a possibility to be utilized during long years as a sympton in photo 6. So tablet fertilizer can have a recommendation to dress much fertilizer at p]anting year and then tree root can get much more chance for absorbing the phosphorus that could keep the high survival and for utilizing it during many years without after dressing. 4. The granurar and powder type phosphate can develop the dense root mat like photo 8 because of giving the large surface for absorbing the phosphorus and weedy root can approch to the nodule for taking the nitrogen element. So this type seems to present better effect than tablet type to control the soil movement, stem weight as 200g per meter(l meter long${\times}$0.1m width). When added the lime any effect could not be found and rather give the negative effect. So Lespedeza seed sowing and phosphorus dressing system seems us to be very reasonable method for covering the raw material of basket making, fodder and fuel wood supply. 7. Fused Mg phosphate and Fused super phosphate are good fertilizer to the soil improving species and dressing more than 30g per seedling can be recommendable amount. 5. In the unproductive and dry soil with phosphorus fertilizer Robinia pseudoacacia and Alnus firnui can grow more than 2.3m in height at 3rd year and Alnus inokumae have the rapid height growth that is more than 1.8m at 2nd year. Depending on the growth situation like the above example minirotated management has possibilities and rapid covering of erosed land can be done with the soil improving species and phosphorus fertilizer. 6. In the Lespedeza sowing plot with 40g Fused Mg phosphate dressing per meter in the eroded and unproductive forest soil Lespedeza have completely covered this poor land and produced the green.

• The Korean Journal of Food And Nutrition
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• 제25권2호
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• pp.368-382
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• 2012

This paper investigated the system that is relevant to Jang(fermented soybean paste or solution), the relief of hunger-stricken people by Jang, 33 kinds of Jang, and its consumption in the documents, such as the annals of the Chosun Dynasty, Ihlseong-document, Seungjeongwon daily, Uigwe(record of national ceremony), official documents on the basis of Kyujanggak institute for the Korean studies and data base of Korean classics. There are lots of Jang named after the place of particular soybean's production from the ancient times. Jang, soybean, salt and Meju(source of Jang), during the Dynasty, were collected as taxation or tribute. In the 5th year of Hyeonjong(1664), the storage amount of soybean in Hojo(ministry of finance) was 16,200 $k{\ell}$, and its consumption was 7,694 $k{\ell}$ a year. In the 32nd year of Yongjo(1756), the 1,800 $k{\ell}$ of soybean was distributed to the people at the time of disaster, and in his 36th year(1756), the 15,426 $k{\ell}$ of soybean was reduced from the soybean taxation nationwide. The offices managing Jang are Naejashi, Saseonseo, Sadoshi, Yebinshi and Bongsangshi. Chongyoongcheong(Gyeonggi military headquarters) stored the 175.14 $k{\ell}$ of Jang, and the 198 $k{\ell}$ of Jang in Yebinshi. There are such posts managing Jang as Jangsaek, Jangdoo, and Saseonsikjang. In the year of Jeongjong(1777~1800), the royal family distributed the 3.6 $k{\ell}$ of Meju to Gasoon-court, Hygyeong-court, queen's mother-court, queen's court, royal palace. The 13.41 $k{\ell}$ of Gamjang(fermented soybean solution) was distributed to the Gasoon-court, 17.23 $k{\ell}$ to Hegyeong-court, 17.09 $k{\ell}$ to the queen's mother-court, and the 17.17 $k{\ell}$ to the queen's court each. There are 112 Jang-storing pots in the royal storages, and the 690 are in Namhan-hill, where the 2.7 $k{\ell}$ of fermented Jang was made and brought back by them each year. At the time of starvation, Jang relieved the starving people. There are 20 occasions of big reliefs, according to the annals of the Chosun Dynasty. In the 5th year of Sejong(1423), the 360 $k{\ell}$ of Jang was given to the hunger-stricken people. In his 6th year(1424), the 8,512.92 $k{\ell}$ of rice, bean, and Jang was provided and in the 28th year(1446), the 8,322.68 $k{\ell}$ of Jang was also provided to them. In the Dynasty, Jang was given as a salary. In case that when they were bereaved, they didn't eat Jang patiently for its preservation. They were awarded for their filial piety. In the annals of the Chosun Dynasty, there are 19 kinds of Jang. They are listed in the order of Jang(108), Yeomjang(90), Maljang(11), Yookjang(5), Gamjang(4), and etc.,. In Seungjeongwon daily, there are 11 kinds of Jang. Jang(6), Cheongjang (5), Maljang(5), and Tojang(3) are listed in order. In the Ihlseong-document, there are 5 kinds of Jang. They are listed in Jang(15), Maljang(2), Gamjang(2), and etc.,. There are 13 kinds of Jang in Uigwe, and the official documents, in the order of Gamjang(59), Ganjang(37), Jang(28), Yeomjang(7), Maljang(6), and Cheongjang(5). In addition, shi are Jeonshi(7), and Dooshi(4). All these are made of only soybean except, for Yookjang. The most-frequently recorded Jang among anthology, cookbook, the annals of the Chosun Dynasty, Ihlseong-document, Seoungjeongwon daily, Uigwe, or official document is Jang(372), and then Yeomjang(194), Gamjang(73), Cheongjang(46), Ganjang(46), Soojang(33), and Maljang(26), which were made of soybean. Jang from China in cookbook is not in anthology and royal palace documents. Thus, traditional Jang made of soybean was used in the daily food life in the royal court, and in the public during the Chosun period.

• Korean Journal of Soil Science and Fertilizer
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• 제5권2호
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• pp.1-38
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• 1972

This study, designed to establish a classification system of paddy soils and suitability groups on productivity and management of paddy land based on soil characteristics, has been made for the paddy soils on the Gimje-Mangyeong plains. The morphological, physical and chemical properties of the 15 paddy soil series found on these plains are briefly as follows: Ten soil series (Baeggu, Bongnam, Buyong, Gimje, Gongdeog, Honam, Jeonbug, Jisan, Mangyeong and Suam) have a B horizon (cambic B), two soil series (Geugrag and Hwadong) have a Bt horizon (argillic B), and three soil series (Gwanghwal, Hwagye and Sindab) have no B or Bt horizons. Uniquely, both the Bongnam and Gongdeog series contain a muck layer in the lower part of subsoil. Four soil series (Baeggu, Gongdeog, Gwanghwal and Sindab) generally are bluish gray and dark gray, and eight soil series (Bongnam, Buyong, Gimje, Honam, Jeonbug, Jisan, Mangyeong and Suam) are either gray or grayish brown. Three soil series (Geugrag, Hwadong and Hwagye), however, are partially gleyed in the surface and subsurface, but have a yellowish brown to brown subsoil or substrata. Seven soil series (Bongnam, Buyong, Geugrag, Gimje, Gongdeog, Honam and Hwadong) are of fine clayey texture, three soil series (Baeggu, Jeonbug and Jisan) belong to fine loamy and fine silty, three soil series (Gwanghwal, Mangyeong and Suam) to coarse loamy and coarse silty, and two soil series (Hwagye and Sindab) to sandy and sandy skeletal texture classes. The carbon content of the surface soil ranges from 0.29 to 2.18 percent, mostly 1.0 to 2.0 percent. The total nitrogen content of the surface soil ranges from 0.03 to 0.25 percent, showing a tendency to decrease irregularly with depth. The C/N ratio in the surface soil ranges from 4.6 to 15.5, dominantly from 8 to 10. The C/N ratio in the subsoil and substrata, however, has a wide range from 3.0 to 20.25. The soil reaction ranges from 4.5 to 8.0. All soil series except the Gwanghwal and Mangyeong series belong to the acid reaction class. The cation exchange cpacity in the surface soil ranges from 5 to 13 milliequivalents per 100 grams of soil, and in all the subsoil and substrata except those of a sandy texture, from 10 to 20 milliequivalents per 100 grams of soil. The base saturation of the soil series except Baeggu and Gongdeog is more than 60 percent. The active iron content of the surface soil ranges from 0.45 to 1.81 ppm, easily-reduceable manganese from 15 to 148 ppm, and available silica from 36 to 366 ppm. The iron and manganese are generally accumulated in a similar position (10 to 70cm. depth), and silica occurs in the same horizon with that of iron and manganese, or in the deeper horizons in the soil profile. The properties of each soil series extending from the sea shore towards the continental plains change with distance and they are related with distance (x) as follows: y(surface soil, clay content) = $$-0.2491x^2+6.0388x-1.1251$$ y(subsoil or subsurface soil, clay content) = $$-0.31646x^2+7.84818x-2.50008$$ y(surface soil, organic carbon content) = $$-0.0089x^2+0.2192x+0.1366$$ y(subsoil or subsurface soil, pH) = $$-0.0178x^2-0.04534x+8.3531$$ Soil profile development, soil color, depositional and organic layers, soil texture and soil reaction etc. are thought to be the major items that should be considered in a paddy soil classification. It was found that most of the soils belonging to the moderately well, somewhat poorly and poorly drained fine and medium textured soils and moderately deep fine textured soils over coarse materials, produce higher paddy yields in excess of 3,750 kg/ha. and most of the soils belonging to the coarse textured soils, well drained fine textured soils, moderately deep medium textured soils over coarse materials and saline soils, produce yields less than 3,750kg/ha. Soil texture of the profile, available soil depth, salinity and gleying of the surface and subsurface soils etc. seem to be the major factors determining rice yields, and these factors are considered when establishing suitability groups for paddy land. The great group, group, subgroup, family and series are proposed for the classification categories of paddy soils. The soil series is the basic category of the classification. The argillic horizon (Bt horizon) and cambic horizon (B horizon) are proposed as two diagnostic horizons of great group level for the determination of the morphological properties of soils in the classification. The specific soil characteristics considered in the group and subgroup levels are soil color of the profile (bluish gray, gray or yellowish brown), salinity (salic), depositonal (fluvic) and muck layers (mucky), and gleying of surface and subsurface soils (gleyic). The family levels are classified on the basis of soil reaction, soil texture and gravel content of the profile. The definitions are given on each classification category, diagnostic horizons and specific soil characteristics respectively. The soils on these plains are classified in eight subgroups and examined under the existing classification system. Further, the suitability group, can be divided into two major categories, suitability class and subclass. The soils within a suitability class are similar in potential productivity and limitation on use and management. Class 1 through 4 are distinguished from each other by combination of soil characteristics. Subclasses are divided from classes that have the same kind of dominant limitations such as slope(e), wettness(w), sandy(s), gravels(g), salinity(t) and non-gleying of the surface and subsurface soils(n). The above suitability classes and subclasses are examined, and the definitions are given. Seven subclasses are found on these plains for paddy soils. The classification and suitability group of 15 paddy soil series on the Gimje-Mangyeong plains may now be tabulated as follows.