化学处理对苎麻胶质多糖组分的影响

探讨了硫酸、氢氧化钠和过氧化氢对苎麻胶质中多糖组分的处理效果,并分析了苎麻胶质中其他成分对氢氧化钠去除苎麻胶质多糖组分的影响.研究表明:硫酸处理可以去除一部分果胶,但对半纤维素没有去除作用;过氧化氢有助于果胶的去除,但对半纤维素的影响不明显;果胶和半纤维素在不同质量浓度的氢氧化钠溶液中的溶解性不同.随着处理时间的延长,果胶和半纤维素含量先迅速降低,后趋于平缓.在常压条件下氢氧化钠处理去除果胶和半纤维素的最佳温度为100℃.脂蜡质、水溶物和果胶对于氢氧化钠去除半纤维素有阻碍作用.水溶物对氢氧化钠溶液去除果胶有阻碍作用.     

竹笋壳化学成分分析

按照GB5888-86<苎麻化学成分定量分析方法>,对所选湖北咸宁的竹笋壳原料进行化学成分定量分析.分别确定了竹笋壳的脂腊质含量为1.33%,水溶物含量为7.73%,果胶含量为0.82名,半纤维素含量为28.12%,木质素含量为20.34%,纤维素含量为41.66%,与苎麻、亚麻、竹原纤维相比,竹笋壳中的纤维素含量偏低,而半纤维素和木质素含量则偏高.     

多糖组分对苎麻纤维性能的影响

采用逐步去除苎麻纤维各胶质成分的方法,分析了果胶和半纤维素对纤维性能的影响.研究结果表明,果胶对纤维分离程度影响很大,半纤维素对纤维分离也有一定影响.随着半纤维素含量的减少,纤维的线密度、断裂伸长率和断裂强度均改善,但当半纤维素含量减少到一定程度时,纤维的线密度、断裂伸长率和断裂强度随着半纤维素含量的减少而改善不明显.综合考虑纤维性能和制成率,半纤维素的含量减少到1.22%左右即可.     

胡麻纤维化学成分定量分析方法和性能的研究

针对亚麻及胡麻的特性,提出一种麻成分的分析方法．通过对亚麻及胡麻各项性能的测试对比分析发现：胡麻纤维的木质素的质量分数比亚麻纤维高,纤维素的质量分数比亚麻低;果胶的质量分数大大高于亚麻纤维;胡麻的聚合度很高,而亚麻纤维的聚合度则较低．     

能源植物狼尾草品种筛选评价指标分析

采用层次分析法建立以能源利用为目的的狼尾草品种筛选评价模型,从生产性能、生物质理化性质、生态适应性以及经济指标等四个方面评价不同狼尾草品种的利用价值.生产性能,单位土地面积的生物质产量是品种筛选评价的首要指标;从乙醇生产角度出发,理想的品种应有较高的纤维素含量和较低的木质素、半纤维素含量;采用直接燃烧、致密成型、热解气化等利用方式,则要求理想的品种应有较高的木质素、纤维素含量和较低的灰分含量.此外,多年生的、能够利用种子繁殖建植草场的、具有较强抗逆性的品种,有利于降低生物质原料的生产成本.     

簸箕柳材性性状株内纵向变异的趋势分析

以簸箕柳为对象,对其木材基本密度,木材纤维素、半纤维素及木质素含量在树干不同高度上的变化趋势进行了研究。结果表明:6株样本木材的基本密度为0.331 2～0.385 4 g/cm³,且在个体内都呈现随着树干高度的增加逐渐降低的趋势; 样本木材的纤维素、木质素及半纤维素含量的变化范围分别为48.69%～56.89%、12.58%～16.42%、19.83%～23.76%,纤维素含量及半纤维素含量在不同个体内由根部到梢部均逐渐降低,木质素含量则表现出两头高、中间低的趋势,并且最高值出现在梢部。方差分析表明,尽管不同个体间木材化学成分含量和基本密度都存在显著差异(达1%极显著性水平),但这些性状在不同植株内沿树干高度的变异均未达显著水平。     

生物质组分在催化快速热解中的相互影响

对纤维素、半纤维素、木质素及3者不同配比的自配生物质样品进行了热重分析与热解-气象色谱-质谱试验。分析了这3种生物质组分与ZSM-5分子筛进行催化热解反应时的相互影响。结果表明尽管纤维素、半纤维素、木质素初级热解产物不同,但在与ZSM-5分子筛催化热解时最终产物基本一致,主要是芳烃类化合物。然而,木质素组分在催化剂表面形成大量积炭并导致催化剂失活。因此木质素组分会影响纤维素与半纤维素组分在催化热解中的转化,导致生物质的整体转化效率下降,并且抑制作用随木质素含量的提高和反应时间的延长而增强。研究结果表明需要对木质素含量较高的生物质进行预处理,选择性去除木质素,提高生物质整体转化效率,降低催化剂失活。     

黑龙江地区小麦麸皮化学组成分析

以我国黑龙江地区的小麦麸皮为原料,对其化学组成成分进行了定量分析,实验测得小麦麸皮中灰分质量分数5．41％、木质素质量分数6．01％、淀粉质量分数25．90％、脂肪质量分数3．45％、戊聚糖质量分数19．42％、综纤维素质量分数46．05％、纤维素的质量分数2．35％及总糖质量分数89．62％,实验结果表明,黑龙江地区的小麦麸皮中综纤维素含量较高,其中以半纤维素为主;戊聚糖含量较高,木质素含量低,易于提取戊聚糖,适应于作为制备功能性食品低聚糖的原料。     

芒果种子茎须的成分分析及芒果纤维性能

首次提出芒果纤维的概念,对芒果种子茎须的化学成分进行测试分析,提取并制备芒果纤维,并对其形态结构、基本性能进行测试分析．结果表明,芒果种子茎须组成成分中,纤维素的含量最高,达到41．12％,木质素次之,再次为半纤维素及水溶物,这4种组分组成了芒果种子茎须主体．芒果纤维外观呈现明显的竖纹沟槽状,外观粗糙,极不光滑．芒果纤维长度离散性较大,单根纤维粗,断裂强度38．3—43．8cN·tex-1,高于棉纤维、黄麻纤维,略低于苎麻纤维,断裂伸长率1．6％～2．7％,远低于棉纤维,略低于苎麻纤维以及黄麻纤维,回潮率9．12％．     

黑莓果实发育成熟期木质素合成CAD酶及其基因表达

【目的】比较黑莓高硬度品种‘Arapaho’和低硬度品种‘Boysen’果实发育成熟期木质素合成肉桂醇脱氢酶(CAD)基因表达,及其与CAD酶活性及总木质素含量的关系。【方法】对不同发育时期的黑莓果肉,利用半定量RT-PCR分析18个RuCADs基因成员的表达,利用比色法测定CAD酶活性,利用滴定法测定总木质素含量。【结果】在黑莓的18个RuCAD基因成员中,有8个CADs基因成员在2个品种发育早、中期果肉中表达量较高; 其中RuCAD16仅在‘Boysen’的早、中期果肉中表达,而在‘Arapaho’中不表达。‘Arapaho’和‘Boysen’果肉CAD酶活性均在着色前即花后9 d和花后21 d时最高,着色后呈下降趋势。‘Arapaho’和‘Boysen’果肉木质素分别在花后24 d和花后27 d含量较高。【结论】‘Arapaho’和‘Boysen’果实着色后,RuCADs基因成员表达呈多样化,且硬度与RuCAD酶及木质素含量关系表现出一定差异; 而在果实发育后期,RuCADs基因表达量降低。CAD酶活性降低及木质素含量下降,与黑莓成熟果实硬度下降具一致性,推测木质素合成与成熟果实硬度形成具有相关性。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the