• 제목/요약/키워드: Iron production

검색결과 608건 처리시간 0.028초

Magnetic Properties of Melt-spun Fe-Nd-C Alloys (급속응고에 의해 제조된 Fe-Nd-C 합금의 자기적 특성)

  • Jang, T.S.;Lim, K.Y.;Cho, D.H.
    • Korean Journal of Materials Research
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    • 제7권12호
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    • pp.1063-1069
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    • 1997
  • For me1t-spun Fe-Nd-C alloys, variation of phase development and magnetic properties with the variety of alloy compositions and production conditions were investigated. To find out whether hard magnetic $Fe_{14}Nd_2C$ is crystallized direct1y from the melt by rapid quenching, the phase development of the as-spun ribbons spun at various speed was a1so studied. For the ribbons spun at 10m/s, ${\alpha}-Fe$ was the primary crystallization phase followed by the secondary $Fe_{17}Nd_2C$. At 20m/s ${\alpha}-Fe$ was suppressed so that the primary $Fe_{17}Nd_2C$ coexisted with the secondary ${\alpha}-Fe$ and the amorphous phase. Above 30m/s the ribbons were a1most amorphous, and the amorphization was complete at 40m/s. $Fe_{14}Nd_2C$ therefore was not found in as-spun state but obtained after heat treating the ribbons. The effective temperature range ($700{\sim}900^{\circ}C$) in which $Fe_{14}Nd_2C$ can be obtained was wider than that of a cast alloy. An alloy made with the wheel speed of 20 or 30m/s yielded higher coercivities after heat treatment. In iron-rich Fe-Nd-C, the composition range in which a high coercivity (more than 10kOe) is expected is narrow, i.e., 77~78 Fe and 7~8 C(at.%).

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Analysis of Immunomodulating Activities in Methanol Extracts from Several Kinds of Grapes (포도 품종별 메탄올 추출물로부터 면역활성 분석)

  • Heo, Jin-Chul;Woo, Sang-Uk;Kweon, Mi-Ae;Kim, Bo-Bae;Lee, Sook-Hee;Lee, Jin-Man;Choi, Jong-Uck;Chung, Shin-Kyo;Lee, Sang-Han
    • Food Science and Preservation
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    • 제14권4호
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    • pp.419-424
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    • 2007
  • Fruits and vegetable extracts are well-known as healthy foods. Such foods have been used as herbal medicines or traditional therapies for centuries. To assess biological activities in grapes, we examined the immunomodulating activities of water extracts from four kinds of grapes (cultivars Kyoho, Delaware, Campbell, and Niagara). We explored possible antioxidant and anticancer activities using antioxidant assays such as the 1,1-diphenyl-2-picrylhydrazyl (DPPH) reduction assay, the ferric iron reducing ability of plasma (FRAP) assay, a cell proliferation assay, an NO inhibition assay, a wound healing assay, and an IL-4/IL-13 elicitation assay. Methanol extracts of grapes were tested. The results showed that each grape extract had potent antioxidant activities. The grape extracts increased cell proliferation and NO production activities in tumor cell lines. IL-4 and IL-13 cytokine levels were decreased in mouse primary spleen cells by treatment with any extract. These results suggest that grape extracts can be used as biomaterials with immunomodulating activities.

Studies of an alcA Gene Involved in Alcaligin Siderophore Biosynthesis in Bordetella bronchiseptica (Bordetella bronchiseptica의 alcaligin siderophore 생합성 유전자인 alcA에 관한 연구)

  • Hwang, Ho-Soon;Kim, Young-Hee;Kim, Sam-Woong;Yu, Jong-Earn;Yoo, Ah-Young;Kang, Ho-Young;Lee, Tae-Ho
    • Journal of Life Science
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    • 제16권7호
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    • pp.1112-1118
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    • 2006
  • Bordetella bronchiseptica, the agent of swine atrophic rhinitis and kennel cough in dogs, is a mucosal pathogen and produces the hydroxamate type alcaligin siderophore under iron-limited conditions. Genes involved in alcaligin siderophore biosynthesis are contained in an alcABCDE operon. In order to provide direct evidence for the role of AlcA in alcaligin biosynthesis, we needed a B. bronchiseptica mutant carrying alcA gene deletion. A 0.6 kb alcA 5'-flanking and 0.7kb 3'-flanking DNA fragments were PCR amplified with the use of pCP1.11 as a template DNA. The 5'-and 3'-flanking DNA fragments were joined in a suicide plasmid, resulting in a recombinant suicide plasmid pDM1. After introduction of pDM1 into B. bronchiseptica by conjugation, the allelic exchange technique was performed and a B. bronchiseptica alcA deletion mutant, named B. bronchiseptica H1, was obtained. The mutant strain produced reduced amount of siderophore as expected. When a plasmid containing complete alcA gene was transformed back into the mutant, the complemented mutant recovered ability of siderophore production. These results indicated that AlcA is one of essential components for the alcaligin siderophore biosynthesis. The mutant strains obtained in this study will be used in the further studies for the biochemical function of AlcA.

Study on the Casting Method and Manufacturing Process of Bronze Bells Excavated from the Hoeamsa Temple Site (회암사지 금탁(琴鐸)의 주조방법과 가공기술 연구)

  • Lee, Jae Sung;Baek, Ji Hye;Jeon, Ik Hwan;Park, Jang Sik
    • Korean Journal of Heritage: History & Science
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    • 제43권3호
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    • pp.102-121
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    • 2010
  • Three bronze bells excavated from the Hoeamsa temple site were investigated for their microstructures and chemical compositions in an effort to understand the technology applied in fabrication, which may represent the related industry established in the early Joseon period. The result shows that the bells were cast from alloys of approximately 85% copper-8% tin-7% lead. The chemical analysis for ten trace elements shows that they were all kept below 0.3 weight %, suggesting that the alloys were made of relatively well-refined copper, tin and lead. The presence of sulfur and iron indicates that chalcopyrite or chalcocite may have been used in the smelting of copper. Evidence has been found that the bells were cast by pouring the liquid metal from the top of the sand molds that were set up in an upright position. No additional treatments, thermal or mechanical, other than a little grinding were applied upon the completion of casting. After the shaping process, a balancing plate was attached to the top of the bell using a steel connection ring. The connection assembly was then fixed to the main body by using molten bronze as a solder. The surface inscription was found carved using different techniques. The differences in the order of strokes and the calligraphic style indicate that the carving was carried out by more than one master. In the absence of documentary evidence on past bronze technology, the present bronze bells with known chronology, provenance and the main agent of production, prove to be a rare and valuable archaeological material for the understanding of the related technology in use in the early Joseon period.

Fundamental Properties of Mortar with Magnet-Separated Converter-Slag Powder as SCM (자력 선별 전로슬래그 미분말을 결합재로 활용한 모르타르의 기초특성)

  • Beom-Soo Kim;Sun-Mi Choi;Jin-Man Kim
    • Journal of the Korean Recycled Construction Resources Institute
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    • 제11권3호
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    • pp.161-168
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    • 2023
  • Converter slag is a by-product generated by refining the pig iron produced into molten steel in the blast furnace, occupying about 15 % of the weight of steel production. It has a high free-CaO content that can generate expansion cracks when used for concrete aggregate. This is the main reason to make it difficult to recycle. To solve this problem, government guideline requires that converter slag has to be aged in an open yard for 90 days. However, aging can not be perfectly performed because it entails time and cost. In this study, we tried to investigate the applicability of converter slag as a cementitious material rather than an aggregate by mixing converter slag with mortar formulations. According to the EDS results of the converter slag in the experiment, we found that screening in the aggregate phase was more effective than that in the powder phase. When the particles separated by a magnet in the aggregate state were pulverized and used for concrete up to a 15 % replacement ratio, various engineering characteristics, such as flow, length change, and compressive strength, showed engineering characteristics similar to those of the control mix.

A Study on the Prior Leaching and Recovery of Lithium from the Spent LiFePO4 Cathode Powder Using Strong Organic Acid (강유기산을 이용한 폐LiFePO4 양극분말로부터 리튬의 선침출에 대한 연구)

  • Dae-Weon Kim;Soo-Hyun Ban;Hee-Seon Kim;Jun-Mo Ahn
    • Clean Technology
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    • 제30권2호
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    • pp.105-112
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    • 2024
  • Globally, the demand for electric vehicles has surged due to greenhouse gas regulations related to climate change, leading to an increase in the production of used batteries as a consequence of the battery life issue. This study aims to selectively leach and recover valuable metal lithium from the cathode material of spent LFP (LiFePO4) batteries among lithium-ion batteries. Generally, the use of inorganic acids results in the emission of toxic gases or the generation of large quantities of wastewater, causing environmental issues. To address this, research is being conducted to leach lithium using organic acids and other leaching agents. In this study, selective leaching was performed using the organic acid methane sulfonic acid (MSA, CH3SO3H). Experiments were conducted to determine the optimal conditions for selectively leaching lithium by varying the MSA concentration, pulp density, and hydrogen peroxide dosage. The results of this study showed that lithium was leached at approximately 100%, while iron and phosphorus components were leached at about 1%, verifying the leaching efficiency and the leaching rates of the main components under different variables.

A Study on Seasonal Variations of Food Consumption of Korean Farmers (한국농촌주민(韓國農村住民)의 계절별(季節別) 식품섭취조사연구(食品攝取調査硏究))

  • Park, Michael Myung-Yun
    • Journal of Nutrition and Health
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    • 제9권1호
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    • pp.43-50
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    • 1976
  • This is the report of a food consumption survey of 193 members of 30 farm families in three rural villages of Korea. From a total of 188 households of the three villages, namely Wolgok in Kyunggi Do Province, Wachon in Kangwon Do Province, and Sobong in Cholla Namdo Province, 30 households were chosen for the survey. Four consecutive seasonal surveys, beginning in the autumn, November 1974 and finishing with the summer, August 1975, were made and each survey covered three consecutive days. The Precise Weighing Method was used in evaluating the kinds of food and nutrient intakes of the subjects. This method entails the accurate weighing of all foods by the investigator just prior to their consumption by the subjects under investigation. This survey was male to determine the actual food eaten by the members of these farm families at each season of the year, and to note any special differences in the foods consumed. The results obtained are summarized as follows: Food Intake The traditional ordinary diet of Korean farmers consists mainly of rice and other cereals as staple foods, and simple subsidary foods. The nutritional shortcomings of rice as a staple food are evident in the subclinical status of nutritional deficiencies. The mean consumption of cereals and their products was very high and it was more than half of the daily total food intake throughout all the seasons. The consumption of animal food, fruits, and fat by the farmers was very low. Fruit intake during winter and spring was almost nil. One of the special foods in the Korean dietary pattern is Kim-chi, a variety of pickled and fermented vegetables. The mean intake of Kim-chi during autumn and winter was very much higher than the other seasons. Korean farmers have difficulties in balanced year-round supply of food due to seasonality of food production and lack of food preservation. As nutrition problems of Korean farmers are highly influenced by seasonal variations, the expansion of an appropriate food preservation and storage programme should be encouraged. Special consideration should be given to new methods of preservation, the types of foods preserved, and production and consumption of nutritionally valuable foods for the improvement of the nutritional status in rural communities. Nutrient Intake Average adult rates for calorie and protein in the three study areas were 0.80 and 0.87 respectively, with little variations by villages. The adult caloric intake in averaged 2,928 kcal for autumn, 2,662 for winter, 2,673 for spring, and 2,760 for summer. Cereals contributed most of the total calories. In terms of the recommended daily dietary allowances for the Korean given by the Korea FAO Association, the diets in this survey were adequate except in the winter and spring. The protein intake averaged from 76.4 grams in autumn to 83.4 grams in summer and was near the recommended allowance, but a relatively large proportion of the total protein came from cereals and their products. The fat intake was unsatisfactory, ranging from 19.2 grams to 29.3 grams for the four seasons, and the consumption during farming season was higher than other seasons. It is apparent that the diet of the Korean farmers should be supplemented by calcium during autumn and winter. The highest calcium intake, with a mean of 583.5 milligrams, was recorded in summer. The mean intake of iron ranged from a low of 9.2 milligrams in the autumn to a high of 15.0 milligrams in the spring and it was satisfactory for all seasons. Among the vitamin group, the daily average intakes of vitamin A, thiamine, riboflavin, and ascorbic acid were lower than the desired intake throughout all the seasons. The mean vitamin A intake as ${\beta}-carotene$ ranged from a low of 2,807.8 IU to a high of 5,221.0 IU. The thiamine intake ranged from 0.98 milligrams to 1.19 milligrams, while mean riboflavin intake ranged from 0.92 milligrams to 1.13 milligrams. Ascorbic acid intake was 37.3 milligrams, the lowest, and the highest 47.8 milligrams. Niacin intake among Korean farmers was higher than the recommended allowance throughout all the seasons, and the mean intake ranged from 18.3 milligrams to 25.8 milligrams. The main character of the Korean farmers' diet has been found low in quality of protein and high in carbohydrate. Attention should be paid to the low intake of vitamin A, thiamine, riboflavin, and ascorbic acid among Korean farmers.

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Production and Assessing Usefulness of the Moving Phantom for Respiration Gated Radiotherapy (호흡동조 방사선치료용 팬텀의 제작 및 유용성 평가)

  • Lee, Yang-Hoon;Lee, Jae-Hee;Yoo, Suk-Hyun
    • The Journal of Korean Society for Radiation Therapy
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    • 제22권2호
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    • pp.135-144
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    • 2010
  • Purpose: The purpose of this study is that through production of phantom for respiration gated radiotherapy, assessing appropriacy of exposure dose for the therapy using RPM (Real-time Position Management). Materials and Methods: We located measurement object on the phantom for respiration gated radiotherapy made of 2 linear actuator, acrylic panel, stanchion, iron plate ets. to drive (up, down, front, back). Using 4D CT scan, we analyzed patient's respiration and reproduced the movement by computer. On the phantom, we located a 2D-Array (PTW) and an White water phantom (4.5 cm) and used DMLC (interval 2 cm) in the field size $10{\times}10\;cm$, then exposed 21EX X-ray 100 MU, in the case of phantom was (1) static (2) moving (3) gated using RPM respectively gantry $0^{\circ}$ and $90^{\circ}$ We measured with a 0.125 CC ionization chamber (PTW) on the phantom (7.5 cm) in the same condition. Results: Ionization chamber: There were within 0.3% of error with gating respiration and approximately 2% of error without gating in the same condition. 2D-Array: Gantry $90^{\circ}$, field size $10{\times}10\;cm$, using DMLC. There were within 3% of error with gating respiration and approximately 16% of error without gating. Conclusion: The phantom for respiration gated radiotherapy makes plans considering patient's movement, quantitative analysis of exposure dose and proper assessment therapy for IMRT patients using RPM possible.

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Development of Water Footprint Inventory Using Input-Output Analysis (산업연관분석을 활용한 물발자국 인벤토리 개발)

  • Kim, Young Deuk;Lee, Sang Hyun;Ono, Yuya;Lee, Sung Hee
    • Journal of Korea Water Resources Association
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    • 제46권4호
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    • pp.401-412
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    • 2013
  • Water footprint of a product and service is the volume of freshwater used to produce the product, measured in the life cycle or over the full supply chain. Since water footprint assessment helps us to understand how human activities and products relate to water scarcity and pollution, it can contribute to seek a sustainable way of water use in the consumption perspective. For the introduction of WFP scheme, it is indispensable to construct water inventory/accounting for the assessment, but there is no database in Korea to cover all industry sectors. Therefore, the aim of the study is to develop water footprint inventory within a nation at 403 industrial sectors using Input-Output Analysis. Water uses in the agricultural sector account for 79% of total water, and industrial sector have higher indirect water at most sectors, which is accounting for 82%. Most of the crop water is consumptive and direct water except rice. The greatest water use in the agricultural sectors is in rice paddy followed by aquaculture and fruit production, but the greatest water use intensity was not in the rice. The greatest water use intensity was 103,263 $m^3$/million KRW for other inedible crop production, which was attributed to the low economic value of the product with great water consumption in the cultivation. The next was timber tract followed by iron ores, raw timber, aquaculture, water supply and miscellaneous cereals like corn and other edible crops in terms of total water use intensity. In holistic view, water management considering indirect water in the industrial sector, i.e. supply chain management in the whole life cycle, is important to increase water use efficiency, since more than 56% of total water was indirect water by humanity. It is expected that the water use intensity data can be used for a water inventory to estimate water footprint of a product for the introduction of water footprint scheme in Korea.

Burqanism from the Origin of the Pastoral Nomadic Koryo Region and the Vision of Korean Livestock Farming (고려의 원시영역 유목초지, 그 부르칸(불함)이즘과 한국축산의 비전)

  • Chu Chae Hyok
    • Journal of The Korean Society of Grassland and Forage Science
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    • 제25권1호
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    • pp.71-82
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    • 2005
  • Khori(高麗) refers to the Chaabog(reindeer) that live on lichens(蘚) on Mt. Soyon(鮮) in which pastures are the cold and dry plateau of North Eurasia. Thus, the origin region of the Khori or Koguryo that are the ancestors of the reindeer-herding pastoral nomads(馴鹿 遊牧民) can be said to be the Steppe-Taiga-Tundra pastoral areas of North Eurasia and North America. When the pastoral nomads moved on to the great mountain(大山) zone of the Jangbaek(長白) to the Baekdu(白頭) Mountains, they could have been in contact with pastoral farmers or agricultural farmers living there and they became the farmers remaining on agricultural farms. They were the Koryo people, the ancestors of Korea. Staying in one place, they gradually forgot the origin of their reindeer-herding pastoral nomadic history in the Northwest area of Mt. Soyon, the small mountain(小山) zone of the Steppe-Taiga-Tundra pastoral areas. In other words, they lost their identity as reindeer-herding pastoral nomads when they entered the agricultural area after leaving the pastoral area. However, since their basic genes had already formed when they lived on the cold and dry plateau of North Eurasia, it is possible to study their pastoral nomadic history focusing on 'the minority living in the broad area(廣域少數)', by utilizing highly advanced biotechnological science and focusing on genes and information technology innovation, and removing various past hindrances in research. Therefore, it is not so difficult to restore the reindeerherding pastoral nomadic history of the Koguryo(高句麗) people and secure their pastoral nomadic identity, of which the first steps have already been taken into their historical stages. The Eurasian continent and the Korean peninsula, especially the cold and dry plateau of North Eurasia and the Korean peninsula have been closely related to each other ecologically and historically. They can never be a separate space at all. The Eurasian continent lies horizontally east to west and thus, the continent forms an isothermal zone. Also, since the time of producing their own foods, it was relatively easy for people with their technology to move to other places owing to the pastoral nomadic characteristic of mobility. Unlike the Chungyen(中原) region, western Asia and the regions covering the Siberia-Manchu-Korean peninsula where food production revolution was first made were connected to the Mongolian lichens route(蘚苔之路: Ni, ukinii jam) and steppe roads. Although the ecological conditions of nature have changed a bit throughout a long history, it was natural for the many tribes in North Asia living on the largest Steppe-Taiga-Tundra area in the world to have believed 'the legends related to animals in relation to their founders and ancestors(獸祖傳說)'. Assuming that Siberian tigers and the tigers living on Mt. Baekdu were connected ecologically and genetically because of the ecological characteristics of the animals, and their migration from plateau to plateau, we would suspect that the Chosun(朝鮮) tribe living on Mt. Baekdu were ethnically and culturally more closely connected to the farther removed Ural-Altai tribes that lived on the cold and dry plateau region than to the Han(i14;) tribe who lived in Chungyen(中原) that was close to Mt. Baekdu. More evidence is the structure of the Korean language which has the form of 'Subject + Object + Verb', which is assumed to have originated from the speedy lifestyle of the reindeer-herding pastoral nomads. The structure is quite different from that of the Han(漢) language, which is based on agricultural life. Also, it is natural for reindeer riding reindeerherding pastoral nomads or horse-riding sheep-herding pastoral nomads(騎馬, 羊遊牧民) to have held military and political power over the region and eventually to have established an ancient pastoral nomadic empire in the process of their conquest of agricultural regions. The stages for founding global empires in the history of mankind maybe largely divided into two, in terms of ecological conditions and occupations. They are the steppes and the oceans. Of course, the steppe-based empires were established based on the skills to deal with horses and the ability to shoot arrows while riding horses, along with the use of iron ware in the 8th century BC. The steppe-based empires became the foundation for an oceanic empire, which could have been established by the use of warships and warship guns since the 15th Century. Based on those facts, we know that Chosun, Puyo(夫餘), and Koguryo are the products of a developmental process of pastoral nomadic empires on the steppes. Maybe we can easily find the pastoral nomadic identity of the Koguryo more than we expected when we trace the origins and history of the Korean tribe living in the pastures located in the northwest area of Mt. Jangbaek by focusing on pastoral nomadic mobility and organization just as we have investigated the historic origins of Anglo-Saxons in America by focusing on the times before the 15th Century. In the process, we should keep in mind that English culture originated from the Industrial Revolution and was directly delivered to the American continent, although America was far from England and was not an intermediate point on long sojourns either. Further, American culture came back to England in a more advanced form later. The most important thing currently to be resolved is to cause Koreans to look back on their own history in a freer way of thinking and with diverse, profound, and sharp insight, taking away the old and existing conventional recognition that is entangled with complicated interests with Korean people and other countries. The meanings of Chosun, Khori, and Solongos have been interpreted arbitrarily without any historic evidence by the scholars who followed conventional tradition of fixed-minded aristocrats in an agricultural society. If the Siberian cultural properties of the stone age, the earthenware age, the bronze age, and the iron age are analyzed in such a way, archaeological discovery will never be able to contribute to the restoration of the Koguryo's pastoral nomadic identity. One should transcend the errors that tend to interpret the cultural properties discovered in the pastoral nomadic regions as not being differentiated from those of agricultural regions and just interpret them altogether from the agricultural point of view. A more careful intention is required in the interpretation of cultural properties of ancient Korean empires that seem to have been formed due to mutual interactions of pastoral nomadic and agricultural cultures. Also, it is required that the conventional recognition chain of 'reverse-genes' be severed, which has placed more weight on agricultural properties than pastoral nomadic ones, since their settlement on agricultural farms was made after the establishment of their ancient pastoral nomadic empires. There is no reason at all to place priority on stoneware, earthenware, bronze ware, and iron ware than on wooden ware(木器) and other ware which were made of animal skins(皮器), bones and horns(骨角器), in analyzing the history in the regions of reindeer or sheep pastures. Reading ancient Korean history from the perspective of pastoral nomadic history, one feels strongly the instinctive emotions to return to the natural 'mother place'. The reindeer-herding pastoral nomadic identity of the Koguryo people that has been accumulated in volumes in their genes and hidden deep inside and have interacted organically could be reborn with Burqanism(Burqan refers to 不咸 in Chinese), which was their religion by birth and symbolized as the red willow(紅柳=不咸). The mother place of the Koguryo's people is the endless vast green pastures of North Eurasia and North America, where we anticipated the development of Korean livestock farming following the inherent properties in the genes of the reindeer-herding pastoral nomads with Korean ancestors. We anticipate that the place would be the core resource that could contribute to the development of life of living creatures following the inherent properties of their genes and biotechnological factors. In other words, biotechnology used for a search for clues on the well-being of humans could be the fruit brought by Burqanism of the Koguryo people and the fruit of the globalization of Korean livestock farming. It is the Chosun farmer in China come from the vast nomadic reindeer pastures of North Eurasia that resolved the food problem of a billion Chinese people with lowland paddy rice seeds (水稻) by transforming Heilongjiang Province(黑龍江省) into an oceanic lowland paddy rice field(水田). Even Mao Tse-tung(毛擇東) could not resolve the food problem by his revolution campaigns for tens of years. Today is the very time that requires the development of special livestock farming following the inherent properties of the ancient Korean reindeer-herding pastoral nomads that respected the dignity of life on the cold and dry plateau of North Eurasia and the America continent. I suggest that research should be started from the pastures of the Dariganga Steppe in East Mongolia that was the homeland of Hanwoo(韓牛) and the central horse-herding steppe place(牧馬場) of Chingis Khan's Mongolia. The Dariganga Steppe is awash with an affluent natural environment for pastoral nomadic living however, the quality of life of the pastoral nomads there is still low. I suggest we Koreans, the descendents of the Koguryo, should take our first steps for our livestock farming business project and develop the Northern nomadic pastures, here at the pastures of the Dariganga Steppe, which is the Mongolian core place of state-of-the-art technology for military weapons.