• 제목/요약/키워드: Natural reduction

검색결과 2,165건 처리시간 0.025초

유기농업의 온실가스 감축효과 (Effects of Organic Farming on Greenhouse Gas Emission Reduction)

  • 김창길;정학균;김용규
    • 한국기후변화학회지
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    • 제7권3호
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    • pp.335-339
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    • 2016
  • The purpose of this study is to analyze effects of greenhouse gas reduction in organic agriculture. To accomplish the objective of the study, a field survey was conducted. Based on the field survey results, LCA method was used to estimate the greenhouse gas emission. The farmer survey and LCA estimation data were provided by The Foundation of Agricultural Technology Commercialization and Transfer. The GHG estimation results showed that GHG emission of organic farming is less by 10.6~89.3% when compared with the conventional farming. In addition, the economic value of greenhouse gas reduction in organic farming amounts to 1,097 million won. Based on major findings, in response to national greenhouse gas reduction target, it is needed to expand organic farming, supporting organic farmers' income.

개발사업에 의한 자연경관 영향 저감방안 중요도 분석에 관한 연구 (A Study on the Analysis of the Importance of Natural Landscape by the Development Project)

  • 신민지;신지훈
    • 농촌계획
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    • 제25권2호
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    • pp.99-117
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    • 2019
  • Environmental impact assessment (EIA), which predicts, evaluates, and manages the influences on natural landscape, plays a role of monitoring natural resources for systematic management of natural landscape. However, the function of verification and correction of the system is still insufficient and feed-back, one of the most important features of EIA follow-up, has not been introduced in Korea's EIA system yet. As a procedure, it is required to check if the opinions of the evaluators are properly reflected to the outcomes of the project through a reviewing process after assessing environmental impacts of a development project. In reality, despite the awareness about the importance of follow-up inspection of the conformity with, the system mainly focuses on the agreement during the planning stage of the development project and fails to continuously manage after its completion. There have been various preceding studies related to prediction, evaluation, and management of environmental impacts on natural landscape for better management. They primarily dealt with the problems in the EIA process and suggested improvement measures, including directions for institutional development, step-by-step goals, and operation methods, to address the problems which arise in the EIA follow-up process. However, suggested measures are not actively applied with the focus only put on institutional operation, there are virtually no standardized methods to predict and assess landscape changes due to the development project and to manage landscape after the project. Against this backdrop, this study aims to explore the existing methods to analyze the impacts natural landscape and to establish a system where landscape management is continued after the development project. To this end, we will suggest reducing methods according to the predicted changes in landscape for post-project management of natural landscape. Characteristics of reduction methods by project type were examined through reviewing the guide to natural landscape rating and the importance of development project impacts on natural landscape by type of reduction was evaluated through questionnaire for experts. Evaluated types of reduction are classified and presented by characteristics of each development project and content of reduction type.

Selective Reduction of Organic Compounds with Non-Free Hydride Reducing Agents

  • Cha, Jin Soon
    • 통합자연과학논문집
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    • 제1권3호
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    • pp.192-194
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    • 2008
  • A series of non-free hydride reducing systems containing boron or aluminum atom, which possess no metal-hydride bond but an available hydrogen at a branched ${\beta}$-position, has been applied to the selective reduction (chemo--, regio-, and stereoselective reduction) of organic compounds. The systems, comprised of diisopinocampheylborane and diisobutylalane derivatives, exhibited almost perfect selectivities in the reduction of aldehydes and ketones. The characteristics features of this systems leading to a perfect transformation have been depicted in this report, especially in the 1) Reduction of ${\alpha}$,${\beta}$-Unsaturated Carbonyl Compounds to Allylic Alcohols via 1,2-Reduction, 2) Chemoselective Reduction between Structurally Different Carbonyl Compounds, and 3) Stereoselective Reduction of Cyclic Ketones.

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메탄가스를 이용한 폐주석산화물의 건식환원시스템 (Research of Dry Reduction Process of Waste Tin Oxide using Methane)

  • 정현철;김세권;김상열
    • 자원리싸이클링
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    • 제31권6호
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    • pp.18-24
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    • 2022
  • 건축용 유리생산공정에서 유리의 평활도 제어를 위한 주석욕조에서 발생하는 폐주석 산화물로부터 천연가스를 이용하여 주석을 회수하는 건식환원공정을 제안하고 환원거동을 고찰하였다. 천연가스 건식환원시스템은 20kg급 연속생산 수직형 반응로로 상부취입, 하부토출 방식으로 시스템을 정립하였다. 모든 반응온도 조건에서 투입가스량이 증가할수록 회수율이 높아지는 결과를 얻었으며, 800℃, 4sccm 조건에서 97.2%의 회수율을 보였다. 반응가스분석결과 23%의 수소를 확인하였으며, 16.6%의 메탄가스 수소전환율을 보였다. 천연가스 환원 주석의 환원반응을 고찰함으로써 폐자원 환원/회수기술 정립에 대한 기초자료를 정립하였다.

희박 천연가스 자동차용 NOx 흡장촉매와 TWC의 NOx 반응특성 비교 (Comparison of NOx Reduction Characteristics of NOx Storage Catalyst and TWC for Lean-burn Natural Gas Vehicles)

  • 최병철;정우남;이춘희
    • 한국자동차공학회논문집
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    • 제12권5호
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    • pp.79-84
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    • 2004
  • We evaluated the reduction performance of NOx storage catalyst and TWC for lean-burn natural gas engine by the model gas. The method of unsteady state reaction was used to compare with reduction performances of NOx storage catalyst and TWC. It was found that the effective parameter was rich spike duration, temperature of the model gas. In the presence of $CO_2$ and $H_2O$ in the reaction mixture was decreased the NOx reduction performance.

일단계 환원/염색에 의한 모직물의 천연인디고 염색 (Natural Indigo Dyeing of Wool by the One Step Reduction/Dyeing Method)

  • 손경희;신윤숙;류동일
    • 한국의류학회지
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    • 제34권3호
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    • pp.508-517
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    • 2010
  • One-step reduction/dyeing method was optimized for wool dyeing with natural indigo dye in this study. The effects of reduction/dyeing conditions including dye temperature and time, the pH of bath, concentration of dye, and reducing agent on dye uptake and color were investigated. The dye uptake was higher with no addition of alkali. Dyeing was carried out through the use of only sodium hydrosulfite in the bath. The maximum dye uptake was obtained at $60^{\circ}C$ for 30min and the dyed fabrics appeared in the PB Munsell color range. Dye uptake improved with the increase of a natural indigo dye concentration with the same sodium hydrosulfite concentration. At a higher dye uptake, the fabric color became more purplish and the maximum absorption shifted from 660nm to 620nm. Color reproducibility was reliable with a color difference in the range of 0.41~1.43. Regardless of color strength, washing and dry cleaning fastnesses were good with a 4/5 rating, and fastnesses to rubbing and light were acceptable with a 3/4~4 rating.

Stoichiometry, Thermal Stability and Reducibility of Perovskite-Type Mixed Oxide LaBO$_3$ (B = Fe, Co, Ni)

  • Park, Il-Hyun;Lee, Hyung-Pyo
    • Bulletin of the Korean Chemical Society
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    • 제9권5호
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    • pp.283-288
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    • 1988
  • The titled properties on reduction of the perovskite $LaBO_3$ (B = Fe, Co, Ni) have been investigated by means of temperature-programmed reduction, isothermal reduction and X-ray diffraction methods. Nominal composition of $LaFeO_{3.18},\;LaCoO_{3.00}\;and\;LaNiO_{2.92}$ are determined. Reduction reaction of these mixed oxides differed according to B-site transition metal and thermal stability on reduction decreased as following order: $LaFeO_{3.18}$ > $LaCoO_{3.00}$ > $LaNiO_{2.92}$. From the results of isothermal reaction, kinetics on reduction of the perovskite has been discussed in detail.

Effect of pertussis toxin pretreated centrally on blood glucose level induced by stress

  • Suh, Hong-Won;Sim, Yun-Beom;Park, Soo-Hyun;Sharma, Naveen;Im, Hyun-Ju;Hong, Jae-Seung
    • The Korean Journal of Physiology and Pharmacology
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    • 제20권5호
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    • pp.467-476
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    • 2016
  • In the present study, we examined the effect of pertussis toxin (PTX) administered centrally in a variety of stress-induced blood glucose level. Mice were exposed to stress after the pretreatment of PTX (0.05 or 0.1 mg) i.c.v. or i.t. once for 6 days. Blood glucose level was measured at 0, 30, 60 and 120 min after stress stimulation. The blood glucose level was increased in all stress groups. The blood glucose level reached at maximum level after 30 min of stress stimulation and returned to a normal level after 2 h of stress stimulation in restraint stress, physical, and emotional stress groups. The blood glucose level induced by cold-water swimming stress was gradually increased up to 1 h and returned to the normal level. The intracerebroventricular (i.c.v.) or intrathecal (i.t.) pretreatment with PTX, a $G_i$ inhibitor, alone produced a hypoglycemia and almost abolished the elevation of the blood level induced by stress stimulation. The central pretreatment with PTX caused a reduction of plasma insulin level, whereas plasma corticosterone level was further up-regulated in all stress models. Our results suggest that the hyperglycemia produced by physical stress, emotional stress, restraint stress, and the cold-water swimming stress appear to be mediated by activation of centrally located PTX-sensitive G proteins. The reduction of blood glucose level by PTX appears to due to the reduction of plasma insulin level. The reduction of blood glucose level by PTX was accompanied by the reduction of plasma insulin level. Plasma corticosterone level up-regulation by PTX in stress models may be due to a blood glucose homeostatic mechanism.

면직물에의 천연 인디고 염색 - 일단계 환원/염색 공정 - (Natural Indigo Dyeing of Cotton Fabric - One-step reduction/dyeing process -)

  • 신윤숙;조아랑;류동일
    • 한국염색가공학회지
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    • 제22권2호
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    • pp.101-109
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    • 2010
  • The objective of this study is to investigate the characteristics of natural indigo dyeing of cotton fabric. Reduction and dyeing were carried out by one-step process using an infrared dyeing machine at the liquor ratio of 1:100, and subsequently oxidation and washing in water were followed. Dye uptake was increased with the increase of indigo concentration. Over the full range of dyeing tests, the dyeing condition was optimized to $40^{\circ}C$ for 40min. For most of dye concentrations, the cotton fabrics showed mainly PB color. Maximum K/S value was shown at 4g/L of sodium hydrosulfite concentration and the color strength increased with the increase of dye concentration. Value(lightness) decreased with the increase of dye uptake irrespective of mercerization or reduction method, while the mercerized cotton showed two times higher dye uptake than the untreated cotton. Whereas hue of the untreated cotton showed large decrease of P character(5.6~3.5 PB) with the increase of dye uptake, that of the mercerized cotton increased P character(4.7~5.5 PB). Irrespective of mercerization, value and chroma decreased with the increased of dye uptake. In addition, the untreated showed lower chroma than the mercerized cotton. In the case of traditional reduction, hue of the untreated cotton was changed very little with the increase of dye uptake. For hydrosulfite reduction, P character decreased with the increase of dye uptake. The difference of hue value was small with the change of reduction method(hydrosulfite reduction or traditional fermentation). Color character was not influenced by the changed maximum absorption wavelength. Washing fastness showed 4~4/5 shade change rating without any staining. And dry rubbing fastness was good at low color strength. The bacterial reduction ratios of dyed cotton fabric were also increased.