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Comparative Study of Water-soluble and Alkali-soluble Hemicelluloses Extracted by Hydrothermal Pretreatment 预览
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作者 LianHua Fu LingYan Meng +1 位作者 YaYu Li MingGuo Ma 《造纸与生物质材料:英文版》 2017年第1期1-9,共9页
The purpose of this study was to explore the differences of the hemicelluloses extracted by hydrothermal pretreatment using water and alkaline solutions(Na OH or KOH). The physicochemical properties and structural cha... The purpose of this study was to explore the differences of the hemicelluloses extracted by hydrothermal pretreatment using water and alkaline solutions(Na OH or KOH). The physicochemical properties and structural characteristics of two water-soluble and four alkali-soluble hemicelluloses extracted from the triploid of Populus tomentosa Carr. through the hydrothermal pretreatment were comparatively studied. It was observed that the alkalis(Na OH and KOH) were more effective than distilled water as extractants. Sugar analysis showed that xylose(66.83%~86.49%) was the major constituent, followed by glucose(6.83%~18.49%). Mannose(1.40%~8.42%), galactose(2.17%~4.05%), and arabinose(0.21%~2.26%) were also detected in the hemicellulosic fractions. The results of gelpermeation chromatography(GPC) indicated that the hemicelluloses extracted using the alkaline solutions had relatively higher molecular weights than those solubilized in distilled water. Further, based on spectroscopic ~1Hnuclear magnetic resonance(~1H-NMR) and two-dimensional heteronuclear singular quantum correlation(2D-HSQC) analyses, it was confirmed that the hemicellulosic fractions had a major structure of(1→4)-b-D-xylan and a minor structure of(1→4)-a-D-glucan with small amounts of substituted sugars and glucuronic acid attached. 展开更多
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Characterization of Hemicelluloses Extracted from Populus tomentosa Carr. by the Hydrothermal Method with Ethanol 预览
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作者 LianHua Fu Shan Liu +2 位作者 ShuMing Li YaYu Li MingGuo Ma 《造纸与生物质材料:英文版》 2017年第3期1-11,共11页
The aim of this study was to investigate the hemicelluloses extracted from Populus tomentosa Carr.by the hydrothermal method with ethanol.The influence of ethanol concentration on the hemicellulosic fractions was syst... The aim of this study was to investigate the hemicelluloses extracted from Populus tomentosa Carr.by the hydrothermal method with ethanol.The influence of ethanol concentration on the hemicellulosic fractions was systematically studied.The chemical compositions and structural features of the hemicellulosic fractions were investigated by a combination of sugar analysis,gel-permeation chromatography,Fourier transform infrared spectroscopy,and one-dimensional proton and carbon-13 nuclear magnetic resonance,and two-dimensional heteronuclear single quantum coherence spectroscopy.Neutral sugar analysis of the hemicellulosic fractions revealed that a higher ethanol concentration(45%~80%) favored the isolation of hemicelluloses with more side chains and lower glucose contents.The molecular weights of these polysaccharides ranged between 2842 g/mol and 5101 g/mol.The results of this study indicate that the hydrothermal ethanol process provides a new pretreatment strategy for the isolation and extraction of biomass. 展开更多
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Solvothermal Synthesis of Boehmite and γ-Alumina Nanorods 预览
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作者 Mingguo MA Yingjie ZHU Guofeng CHENG Yuehong HUANG 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2008年第4期 637-640,共4页
<正>Boehmite nanorods were synthesized by a solvothermal method using AlCl_3·6H_2O in mixed solvents of water and aniline.The solvothermal time,heating temperature and the concentration of aniline have effe... <正>Boehmite nanorods were synthesized by a solvothermal method using AlCl_3·6H_2O in mixed solvents of water and aniline.The solvothermal time,heating temperature and the concentration of aniline have effects on the morphology of boehmite.γ-alumina nanorods were prepared by a simple thermal transformation of boehmite nanorods.A rational mechanism based on the oriented attachment is proposed for the formation of boehmite nanorods.The products were characterized by X-ray powder diffraction(XRD)and transmission electron microscopy(TEM).Photoluminescence(PL)spectrum of the boehmite nanorods was also investigated. 展开更多
关键词 水软铝石 水热合成 Γ-氧化铝 纳米棒
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对噻枯唑具有抗性的水稻白叶枯病菌菌株的性质 预览 被引量:14
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作者 周明国 马忠华 《植物保护学报》 CAS CSCD 北大核心 1997年第2期 155-158,共4页
对田间和室内分别筛选的抗噻枯唑的水稻白叶枯病菌菌株性质研究发现:室内筛选的抗药菌株在水稻上失去致病性,而田间抗药菌株在离体下则不表现抗药性;抗噻枯唑的菌株对敌枯唑表现交互抗性,对叶枯净不表现交互抗性;抗性菌株与敏感菌... 对田间和室内分别筛选的抗噻枯唑的水稻白叶枯病菌菌株性质研究发现:室内筛选的抗药菌株在水稻上失去致病性,而田间抗药菌株在离体下则不表现抗药性;抗噻枯唑的菌株对敌枯唑表现交互抗性,对叶枯净不表现交互抗性;抗性菌株与敏感菌株混合接种于无药水稻上发现,抗性菌株的竞争力稍低于敏感菌株;供试的抗性菌株在无药平板上转移6代后,抗性仍很稳定,但在无药的水稻上反复接种、分离4代后,抗性水平有所下降。 展开更多
关键词 水稻 白叶枯病菌 噻枯唑 抗药性
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华北克拉通西部古元古代孔兹岩系的地层对比、岩相古地理特征及其地质意义 预览 被引量:4
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作者 钟焱 陈雅丽 +1 位作者 翟明国 马旭东 《岩石学报》 SCIE CAS CSCD 北大核心 2016年第3期713-726,共14页
位于华北克拉通西部的孔兹岩系是探讨华北克拉通形成及演化过程的关键对象之一,近年来的研究显示这套富铝质沉积岩系在1.95~1.82Ga期间经历了高压/高温和超高温-高温/中(低)压两期变质作用。已发表的钻井资料表明鄂尔多斯中、新生代... 位于华北克拉通西部的孔兹岩系是探讨华北克拉通形成及演化过程的关键对象之一,近年来的研究显示这套富铝质沉积岩系在1.95~1.82Ga期间经历了高压/高温和超高温-高温/中(低)压两期变质作用。已发表的钻井资料表明鄂尔多斯中、新生代盆地的基底岩石在源区特征、沉积时代、岩石矿物组合和变质时代等方面均与孔兹岩系十分类似,暗示孔兹岩系的原岩分布和后期的高级变质作用范围可能涉及到了鄂尔多斯地块内部。然而,目前对于孔兹岩系的原岩分布、等时性和沉积环境等问题仍有争议,这些问题对于约束孔兹岩系的时空分布和理解华北克拉通西部地区的构造演化过程具有十分重要的科学意义。基于地层学角度的尝试,本文选取贺兰山、大青山和集宁地区的孔兹岩系进行了沉积层序的划分及对比,并初步恢复了相应时期鄂尔多斯地块的岩相古地理特征。本文的研究结果表明:(1)鄂尔多斯地块北缘的贺兰山、大青山和集宁等地区的孔兹岩系均由可对比的三个沉积层序组成;(2)这套沉积岩系的分布范围呈面状延伸至鄂尔多斯地块内部,指示华北克拉通西部曾存在一个克拉通内盆地性质的"鄂尔多斯陆表海",其海侵方向可能由贺兰山-鄂尔多斯地块内部指向大青山、集宁等地区;(3)鄂尔多斯陆表海可能发育于2.5~2.3Ga"构造寂静期"的某一阶段,此间堆积的孔兹岩系(丰镇群)原岩很可能是代表华北陆块完成克拉通化过程的标志性盖层。 展开更多
关键词 孔兹岩系 沉积层序 岩相古地理 鄂尔多斯陆表海
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