• Journal of Microbiology and Biotechnology
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• 제25권8호
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• pp.1241-1245
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• 2015

The aim of the present work was to examine the putative promoter region of the operon ansPAB and to determine the general elements required for the regulation of transcriptional activity. The transcriptional start site of the ansPAB promoter was determined by using highresolution S1-nuclease mapping. Sequence analysis of this region showed -10 and -35 elements, which were consistent with consensus sequences for R. etli promoters that are recognized by the major form of RNA polymerase containing the σ⁷⁰ transcription factor. Mutation studies affecting several regions located upstream of the transcriptional start site confirmed the importance of these elements on transcriptional expression.

• 한국자동차공학회논문집
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• 제22권7호
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• pp.90-97
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• 2014

The effects of high pressure and low pressure exhaust gas recirculation (HP/LP EGR) portion on diesel engine combustion and emissions characteristics were investigated in a 2.2 L passenger-car diesel engine. The po3rtion of HP/LP EGR was varied from 0 to 1 while fixing the mass flow rate of fresh air. The intake manifold temperature was lowered with the increasing of the portion of LP EGR, which led to the retardation of heat release by pilot injection. The lowered intake manifold temperature also resulted in low nitrogen oxide (NOx) emissions due to decreased in-cylinder temperature and prolonged ignition delay, however, the carbon monoxide (CO) emission showed opposite trend to NOx emissions. The brake specific fuel consumption (BSFC) was decreased as the portion of LP EGR increased due to lowered exhaust manifold pressure by wider open of turbocharger vane. Consequently, the trade-off relationship between NOx and BSFC could be improved by increasing the LP EGR portion.

• The Plant Pathology Journal
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• 제17권2호
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• pp.67-70
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• 2001

Medicago truncatula is a diploid legume plant related to the forage crop alfalfa. Recently, it has been chosen as a model species for genomic studies due to its small genome, self-fertility, short generation time, and high transformation efficiency. M. truncatula engages in symbiosis with nitrogen-fixing soil bacterium Rhizobium meliloti. M. truncatula mutants that are defective in nodulation and developmental processes have been generated. Some of these mutants exhibited altered phenotypes in symbiotic responses such as root hair deformation, expression of nodulin genes, and calcium spiking. Thus, the genes controlling these traits are likely to encode functions that are required for Nod-factor signal transduction pathways. To facilitate genome analysis and map-based cloning of symbiotic genes, a bacterial artificial chromosome library was constructed. An efficient polymerase chain reaction-based screening of the library was devised to fasten physical mapping of specific genomic regions. As a genomics approach, comparative mapping revealed high levels of macro- and microsynteny between M. truncatula and other legume genomes. Expressed sequence tags and microarray profiles reflecting the genetic and biochemical events associated with the development and environmental interactions of M. truncatula are assembled in the databases. Together, these genomics programs will help enrich our understanding of the legume biology.

• 한국분무공학회지
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• 제26권2호
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• pp.57-66
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• 2021

The reactivity controlled compression ignition (RCCI) is the technology that provides two different types of fuel to the combustion chamber with the advantage of significantly reducing particulate matter and nitrogen oxides emissions. However, due to the characteristics of lean combustion, combustion efficiency is worsened. The conventional type of pistons for conventional diesel combustion (CDC) has mostly been used in the researches on RCCI. Because the pistons for CDC are optimized to enhance flow and target spray, the pistons are unsuitable for RCCI. In this study, a piston that is suitable for RCCI is designed to improve combustion efficiency. The new piston was designed by considering the factors such as squish geometry, bowl depth, and surface area. The experiment was carried out by fixing the energy supply to 0.9kJ/cycle and 1.5kJ/cycle respectively. The two pistons were quantitatively compared in terms of thermal efficiency and combustion efficiency.

• 한국토양비료학회지
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• 제21권2호
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• pp.149-159
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• 1988

담수토양(湛水土壤)에서의 농약(農藥)의 처리(處理)가 질산화성균(窒酸化成菌), 질산환원균(窒酸還元菌), 탈질균(脫窒菌), 질산화작용(窒酸化作用), 질소고정미생물(窒素固定微生物) 및 질소고정력(窒素固定力)에 미치는 영향(影響)을 조사분석(調査分析)한 결과(結果)를 요약(要約)하면 다음과 같다. 암모니움산화균(酸化菌)은 농약처리구(農藥處理區)에 있어서 균수(菌數)가 감소하였으며, 아질산산화균(亞窒酸酸化菌)은 cabamate계(系) 살충제(殺蟲劑)인 carbofuran과 MIPC 처리구(處理區)에서 균수(菌數)가 감소하였고 질산환원균(窒酸還元菌)과 탈질균(脫窒菌)은 농약처리구(農藥處理區)가 대조구(對照區)에 비해 균수(菌數)가 감소하였으나 simetryne 처리구(處理區)에 있어서는 배양(培養) 60일(日)경에 탈질균(脫窒菌)이 증가(增加)하는 경향(傾向)이었다. $NO_2{^-}$와 $NO_3{^-}$ 생성량(生成量)은 농약처리(農藥處理)에 의해 경시적(經時的)으로 감소하는 경향(傾向)이었다. azotobacter 속균(屬菌)과 clostridia 속균(屬菌)은 농약(農藥)에 의해 크게 저해받지 않았으며 홍색무황세균(紅色無黃細菌)과 홍색황세균(紅色黃細菌)은 제초제인 simetryne 처리구(處理區)에서 균수(菌數)가 감소하였고 blue-green algae는 acephate 처리구(處理區)에서 균수(菌數)가 증가(增加)하는 경향(傾向)이었다. acetylene 환원력(還元力)은 acephate 처리구(處理區)에서 높은 경향(傾向)을 보였으며 일반적으로 살충제(殺蟲劑)나 제초제(除草劑)의 살포가 토양(土壤)의 질소고정력(窒素固定力)에 크게 영향을 주지는 않는 것 같다.

• Journal of Microbiology and Biotechnology
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• 제30권8호
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• pp.1169-1179
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• 2020

In this study, two soybean genotypes, i.e., aluminum-tolerant Baxi 10 (BX10) and aluminumsensitive Bendi 2 (BD2), were used as plant materials and acidic red soil was used as growth medium. The soil layers from the inside to the outside of the root are: rhizospheric soil after washing (WRH), rhizospheric soil after brushing (BRH) and rhizospheric soil at two sides (SRH), respectively. The rhizosphere bacterial communities were analyzed by high-throughput sequencing of V4 hypervariable regions of 16S rRNA gene amplicons via Illumina MiSeq. The results of alpha diversity analysis showed that the BRH and SRH of BX10 were significantly lower in community richness than that of BD2, while the WRH exhibited no significant difference between BX10 and BD2. Among the three sampling compartments of the same soybean genotype, WRH had the lowest community richness and diversity while showing the highest coverage. Beta diversity analysis results displayed no significant difference for any compartment between the two genotypes, or among the three different sampling compartments for any same soybean genotype. However, the relative abundance of major bacterial taxa, specifically nitrogen-fixing and/or aluminum-tolerant bacteria, was significantly different in the compartments of the BRH and/or SRH at phylum and genus levels, indicating genotype-dependent variations in rhizosphere bacterial communities. Strikingly, as compared with BRH and SRH, the WRH within the same genotype (BX10 or BD2) always had an enrichment effect on rhizosphere bacteria associated with nitrogen fixation.

• 한국농공학회논문집
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• 제62권5호
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• pp.39-46
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• 2020

This study evaluated the nitrogen oxide (NO_x) removal efficiency by air purification concrete blocks with titanium dioxide (TiO₂). The concrete in the mixtures had a 30% water:cement ratio, to which TiO₂ was added at 0%, 5%, and 10% of cement weight. The compressive strength reduction rate and removal efficiency of NO_x were investigated. The result of the compressive strength test in the study indicated that addition rate of TiO₂ did not lead to signifcant effect. In terms of the average removal efficiency of NO_x, mix No. 1 using a TiO₂ mixing ratio of 0% had a removal efficiency of 0.57% on average; thus, the removal effect w as not significant. For the other samples prepared by mixing, the average removal efficiencies for mix No. 2 (5% TiO₂) were 58.86% and 62.05% for normal and washing surface treatments, respectively, and those of sample No. 3 (10% TiO₂) were 59.94% and 67.61%. mixs No. 4 (5%) and No. 5 (10%), in which TiO₂ diluted with distilled water was sprayed onto the block surface, had an average NO_x removal efficiency of 61.72% and 68.48%, respectively. In terms of NOx removal efficiency, Mixs No. 3 and No. 5 with 10% TiO₂ were better than Mixs No. 2 and No. 4 with 5% TiO₂. In addition, analyzing the NO_x removal efficiency results from the fixing method, it was capable to apply mixing (washing) and the diluted spray methods. Therefore, it was found that the diluted spray method applied in this study can be employed in any manufacture of air purification concrete blocks.

• Applied Biological Chemistry
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• 제22권3호
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• pp.166-172
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• 1979

두과목초(荳科牧草)의 증산(增産)과 질산비료(窒酸肥料)의 소비절약(消費節約)을 위(爲)하여 근류균(根瘤菌)의 실용화(實用化)를 위(爲)한 일련(一連)의 연구(硏究)를 시도(試圖)하고 그 기초연구(基礎硏究)로서 알팔과군(群)을 대상(對象)으로 근류균(根瘤菌)을 분리(分離)하고 우수균주(優秀菌株)를 선발(選拔)하였다. 1. 대관령(大關嶺), 제주도(濟州道) 및 기타지역(其他地域)에서 수집(蒐集)한 근류(根瘤)로부터 47주(株)의 근류균(根瘤菌)을 분리(分離)하였다. 2. 분리균주(分離菌株)에 대(對)하여 형태적(形態的) 및 배양적(培養的) 성질(性質)을 검토(檢討)하는 동시(同時)에 항원(抗原)의 특성(特性)을 비교(比較)하고 lysogeny 여부(與否)를 확인(確認)한 결과(結果) : (1) yeast mannitol broth 및 agar 상(上)에서의 생육형태(生育形態) 및 증식속도(增殖速度)를 달리하였으며 congo red에 의한 착색정도(着色程度)에도 차이(差異)가 있었고 (2) 항원성(抗原性)의 상호(相互) 근연성(近緣性)이 인정(認定)적는 균주(菌株)는 M-11/SU47, M-13/M-15 및 M-3/M-5 이었으며 (3) latent phage의 감염균주(感染菌株)가 발견(發見)되지 않았다. 3. 항온조명실내(恒溫照明室內)에서 행(行)한 시험관법(詩驗管法)에 의한 식물접종시험(植物接種試驗)을 통(通)하여 분리균주(分離菌株)의 근류형성(根瘤形成) 및 질소고정능력(窒素固定能力)을 비교한 결과(結果), 공시숙주식물(供試宿主植物)에 대(對)하여 근류(根瘤)를 형성(形成)하지 못하는 즉(卽) 친화력(親和力)이 없는 균주(菌株), 근류(根瘤)는 형성(形成)하나 숙주식물(宿主植物)의 생육(生育)에는 영향(影響)을 주지 못하는 무효균주 그리고 숙주식물(宿主植物)의 생육(生育)을 크게 촉진(促進)하는 유효균주등으로 구분(區分)할 수 있었으며 특(特)히 유효균주중에서 M-8, 9, 14, 20, 21, 25 및 34균주등(菌株等)은 질소시용구(窒素施用區) 수준(水準) 또는 그 이상(以上)으로 숙주식물(宿主植物)의 생육(生育)에 유효한 결과(結果)를 나타내었다.

• 한국유기농업학회지
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• 제26권4호
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• pp.719-729
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• 2018

국내 유기농 밭 토양은 가축분퇴비, 유기질비료 등의 지속적인 투입에 의해 인산을 포함한 다량 양분이 축적되고 있다. 친환경 토양관리를 위하여 가축분퇴비나 유기질비료의 대안으로 보리(B)와 헤어리베치(H)의 혼파를 활용하고자 한다. 보리와 헤어리베치의 혼파가 녹비작물의 수량 및 양분 생산성에 미치는 효과를 평가하기 위하여, 가축분퇴비 연용으로 토양 양분이 축적된 유기농 밭 토양에 보리와 헤어리베치를 2016년 11월에 기준 파종량(B 160 kg/ha ; H 90 kg/ha) 대비 B 66%와 H 33%, B 33%와 H 66% 비율로 혼파 재배하였다. 수확기에 녹비작물 수량, 양분생산성을 분석하여 혼파 효과를 평가한 결과는 아래와 같다. 보리와 헤어리베치를 혼파 할 경우 녹비작물 수량이 헤어리베치 단파 보다 78~132% 증가되어, 혼파시 수량증대 효과가 있었다. 질소 생산성도 혼파에서 보리 단파보다 43~44% 증가, 인산 생산성도 헤어리베치 단파보다 200% 이상 증가되어 혼파의 양분생산성 증대 효과를 확인하였다. 본 연구 결과 보리와 헤어리베치의 혼파재배는 녹비작물의 수량 및 질소와 인생산성 증대에 효과적이라는 결과를 얻었으며, 2가지 측면을 모두 고려할 때, 기준 파종량 대비 보리 66%와 헤어리베치 33%를 혼파하여 파종한 처리(B66H33)가 가장 비료로써의 가치가 높아 양분이 축적된 유기농경지에서 활용할 수 있을 것으로 판단된다.

• 한국토양비료학회지
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• 제20권4호
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• pp.359-367
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• 1987

수종(數種)의 유기산(有機酸), 당류(糖類)(단당(單糖), 복합당(複合糖)) 및 수도근계분비물질(水稻根系分泌物質)에 대(對)한 협생질소고정균(協生窒素固定菌)의 화학주화성(化學走化性)을 검토(檢討)하기 위하여 우리나라 서해간척지(西海干拓地)의 잡초(雜草) 및 수도(水稻) 근조직(根組織)에서 분리동정(分離同定)한 균(菌)을 공시(供試)하여 시험(試驗)하였다. 공시(供試)한 협생질소고정균중(協生窒素固定菌中) Azospirillum lipoferum Ecc 3-1은 유인물질(誘引物質)이 있는 방향(方向)으로 이동(移動)하기 위한 천이환(遷移環)을 만들었으나 Agrobacterium radiobacter Ecc 1-1과 Pseudomonas sp Ecc 4-1은 천이환(遷移環)을 만들지 않했다. 당류(糖類) 및 유기산(有機酸)에 대(對)한 공시세균(供試細菌)의 화학주화성(化學走化性)은 D(+)-glucose나 D(+)-fructose 보다 malic acid나 citric acid에 대(對)한 주화성(走化性)이 높았다. 특(特)히 복합당(複合糖)인 D-galactouronic acid와 L-aspartate는 공시(供試)한 타종(他種)의 당류(糖類)나 유기산(有機酸)보다 가장 높은 주화력(走化力)을 보였다. 수도근분비물질(水稻根分泌物質)에 대(對)한 공시협생질소고정균(供試協生窒素固定菌)의 주화성(走化性)을 수도품종(水稻品種)과 세균간(細菌間)에 서로 상이(相異)한 교호관계(交互關係)를 보였다.