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강성구,정윤중 明知大學校 産業技術硏究所 2005 産業技術硏究所論文集 Vol.24 No.-
Tungsten carbide(WC) powders were synthesized by self-propagating high temperature synthesis(SHS) chemical furnace that microwave heating system. Attempt to find the optimal condition for synthesis of tungsten carbide(WC), the effects of molar ratio between carbon and tungsten, compaction pressure, pellet thickness and heating time of microwave on synthesis were investigated. Powder was synthesized in Ar atmosphere. Chemical fuel was Ti-C mixed powder. Compositional and structural characterization of these powders was carried out by scanning electron microscope(SEM) and x-ray diffraction(XRD). Powder characterization was carried out by the measurement of particle size distribution with laser-particle size analyzer. Tungsten carbide(WC) obtained by microwave depend very much on the mole ratio between carbon and tungsten and heating time of microwave given in a product, i.e. Optimum molar ratio of synthesized powder was tungsten : carbide = 1 : 1.5, pellet thickness 10㎜, compaction pressure l500Psi and microwave heating time was 60sec after propagation to best condition powder. By optimizing the synthesis conditions, it is possible to fabricate tungsten carbide(WC) powders which have little secondary phases.
박윤점,허북구,윤재길,강호종 한국화훼연구회 2002 화훼연구 Vol.10 No.2
꽃바구니 127개를 대상으로 사용된 절화, 절지 및 절엽의 종류와 특성을 조사하였다. 꽃바구니는 절화 1종만으로 꽂은 것이 36.0%, 2종류로 꽂은 것이 37.7%로 2종류 이하가 73%나 차지하였다. 절화 1종만으로 꽂은 꽃바구니 중 43.5%는 소국을, 27.5%는 장미, 17.8%는 백합을 이용하였다. 절화 2-3종이 조합을 이룬 꽃바구니에서는 소국, 장미, 안개꽃, 백합의 사용이 많았다. 꽃바구니에 사용된 절화 형태는 매스플라워 37.2%, 필러플라워 30.3%, 폼플라워 22.4%, 라인플라워 10.1%였다. 꽃바구니에 사용된 절화의 색 조합은 단색만 사용된 꽃바구니가 39.9%, 2색이 사용된 것이 43.1%였으며, 3색 이상이 사용된 꽃바구니는 17.0%였다. 꽃바구니에 사용된 절화의 길이는 폼플라워와 매스플라워는 21-50cm, 라인플라워는 31-60cm, 필러플라워는 10-40cm가 많았다. 꽃바구니에 사용된 절지 및 절엽중에 1종류만 사용된 것이 45.9%, 2종이 사용된 것이 37.5%, 3종이상이 사용된 것이 12.5%였으며, 아스파라거스, 편백, 사스레피나무가 많이 사용되었다. 꽃바구니에 사용된 절지 및 절엽의 형태는 필러폴리지가 56.3%, 매스폴리지가 25.1%, 폼폴리지가 15.0% 순이였다. Kinds and characteristics of cut flower, cut branch and cut foliage used for flower baskets were investigated. Flower baskets using olny 1 cut flower is 36% and 2 kinds of cut 37%. Among flower baskets using 1 species of cut flower, 43.5% used spray chrysanthemu, rose, Gypsophila and lily. Among gorms of cut flowers for flower basket, mass flower is 37.2%, filler flower 30.3%, form flower 22.4%. Among colors of cut flowers for flower basket, only 1 color is 39.9%, 2 colors 43.1% and above 3 colors 17%. Length of cut flower used for flower basket is 21-50cm in form and mass flower, 31-60cm in line flower, 10-40cm in filler flower. As for cut branch and cut foliage used for flower basket, only mainly Asparagus, Chamaecyparis and Eurya. As for cut branch and cut foliage used for flower basket, filler foliage is 56.3%, mass foliage 25.1% and form foliage 15%.
Anti-osteoporotic Effects of Sericin-Calcium Conjugate in Ovariectomized Rats
Ehn-Kyoung Choi, Dongsun Park, So-Young Choi , Yun-Hui Yang, Seock-Yeon Hwang, Seongho Yeon, Jeong-Yong Lee, Ill-Hwa Kim, Yun-Bae Kim, Hyun-Gu Kang1 충북대학교 동물의학연구소 2011 Journal of Biomedical and Translational Research Vol.12 No.2
This study was conducted in order to evaluate the effect of sericin-calcium (SC) as therapy for ovariectomy-induced osteoporosis in rats. Three weeks after ovariectomy (OVX), Sprague-Dawley rats were divided randomly into three groups: sham-operated group (Sham), ovariectomized group, and SC-treatment group (OVX+SC). Rats in the OVX+SC group were given drinking water containing 0.07% SC for eight weeks. Bone breaking force, mineralization, and blood parameters related to bone metabolism were analyzed. In OVX animals, blood concentration of 17β-estradiol showed a significant decrease, while osteocalcin and type I collagen C-terminal telopeptides (CTx) showed an increase. Breaking force of femurs as well as bone mineral density (BMD), ash, calcium, and phosphorus in femurs showed a significant decrease following OVX. Treatment with SC (0.07% in drinking water) resulted not only in remarkable restoration of the decreased 17β-estradiol and increased osteocalcin and CTx concentrations, but also led to recovery of decreased femoral breaking force, BMD, ash, calcium, and phosphorus. It is suggested that SC effectively improves bone density by preventing bone turnover-mediated osteocalcin, CTx, and minerals, and that it could be a potential candidate for use in therapy or prevention of post-menopausal osteoporosis.
Measurement of NH₃ Volatilization from Organic Fertilizer Using a Dynamic Chamber
Yun-Gu Kang(강윤구),Jae-Han Lee(이재한),Jin-Hyuk Chun(천진혁),Yong-Jun Yu(유용준),Jun-Yong Lee(이준영),Gi-Bum Yi(이기범),Taek-Keun Oh(오택근) 한국토양비료학회 2021 한국토양비료학회 학술발표회 초록집 Vol.2021 No.11
Most organic fertilizers are manufactured using imported ingredients and organic fertilizer can improve the agricultural productivity through soil fertility improvement and microbial activity increase. Ammonia (NH₃) is mostly emitted from the agricultural sector and the NH₃ emission from fertilizer use is about 7%. Biochar can be produced under oxygen-limited conditions using several biomass and biochar has effects such as carbon sequestration and heavy metal adsorption in the soil. In this study, the organic fertilizers (OF) were classified according to the type of ingredients and the mixing ratio, and the NH₃ emission was evaluated using a dynamic chamber method. OF1 and OF2 are commonly used organic fertilizers in domestic, and OF3 and OF4 are manufactured by mixing biochar. When only organic fertilizers were used, OF1 represented the highest emission (25.12 kg ha<SUP>-1</SUP>), and when both organic and inorganic fertilizers were treated, OF3+NPK expressed the most volatilization (155.41 kg ha<SUP>-1</SUP>). When biochar is added to organic fertilizer, the pH and total nitrogen content of the organic fertilizer decreased and the total carbon content and inorganic contents increased. However, when organic fertilizer contained biochar is treated to the soil, it is thought to be beneficial to growth of crops by increasing the content of phosphate and potassium. This study evaluated the possibility of replacing some of the ingredients of organic fertilizer with biochar and the emitted NH₃. Results showed that it is most advantageous to promote crop growth when producing like OF4 type.
Kang Yun-Gu,Lee Jae-Han,Lee Jun-Yeong,Kim Jun-Ho,Oh Taek-Keun,Sung Jwa-Kyung 한국응용생명화학회 2023 Applied Biological Chemistry (Appl Biol Chem) Vol.66 No.-
Ammonium ions (NH4+) are commonly found in contaminated water and are a contributing factor to water eutrophication. Carbonized rice husk, derived from various biomass sources, possesses a porous structure, and its characteristics are influenced by the feedstock and pyrolysis conditions. Hence, this study aimed to investigate the applicability of carbonized rice husk as an absorbent for NH4+ removal. The adsorption kinetics were analyzed using the Pseudo-first-order and Pseudo-second-order models, while the adsorption characteristics were assessed using the Langmuir and Freundlich isotherms. The adsorption rate of NH4+ by carbonized rice husk increased until 240 min and then gradually approached equilibrium state. Notably, the highest NH4+ adsorption rate was observed in pH 7.1 carbonized rice husk 36.045 mg/g∙min. Moreover, the NH4+ adsorption capacity exhibited an increase with increasing concentration and quantity of the solution. The pH of the carbonized rice husk was found to influence the NH4+ adsorption process, with higher pH values corresponding to increased NH4+ adsorption rates. The NH4+ sorption rate carbonized rice husk was higher in pH 11.0 at 31.440 mg/g compared to pH 6.1 (7.642 mg/g) and pH 7.1 (10.761 mg/g). These findings highlight the impact of pyrolysis conditions on the adsorption characteristics of carbonized rice husk.
Yun-Gu Kang(강윤구),Nam-Ho Kim(김남호),Jun-Ho Kim(김준호),Da-Hee Ko(고다희),Gi-Bum Yi(이기범),Taek-Keun Oh(오택근) 한국토양비료학회 2021 한국토양비료학회 학술발표회 초록집 Vol.2021 No.11
Biochar can be obtained when various biomass and feedstocks are pyrolyzed under oxygen-limited conditions. Biochar enhances plant growth and sequestrates carbon semi-permanently with a stable structure in the soil. The rice husk and rice straw used as experimental ingredients are most common agricultural waste in Korea. A wood vinegar is a liquid produced by liquefied smoke generated when wood is heated at high temperature to produce charcoal. Wood vinegar improves the growth of plants and inhibits diseases and pests. The objective of this study was to evaluate the effect of biochar produced from rice husk and rice straw as well as wood vinegar on the growth of perilla (Perilla frutescens var.) and soil chemical properties. The experiment was conducted by using a wagner pot (1 5000 a<SUP>-1</SUP>) in a glass greenhouse from March 30 to May 28, 2021. The biochar was prepared by pyrolysis at 450°C for 30 minutes, and the wood vinegar was diluted to 1:500 (v v<SUP>-1</SUP>). The combination of biochar and wood vinegar produced the highest yields. Soil pH increment was only observed in the soil treated with the rice straw biochar, soil EC increased in all the treatments except for the control. The carbon content of the soil was highest in the rice husk biochar treatment. Based on the results of this study, both biochar and wood vinegar are agriculturally productive.