预处理方法对细菌降解玉米秸秆产氢能力的影响

为提高细菌降解玉米秸秆产氢能力,实验研究了酸化汽爆预处理、硫酸预处理、氢氧化钠预处理和氨水预处理4种预处理方法对细菌Clostridium sp.X9降解玉米秸秆发酵产氢能力的影响.结果表明,酸化汽爆为最佳的预处理方式.在酸化汽爆预处理条件为硫酸体积分数1%、汽爆温度121℃和汽爆时间2 h时,纤维素降解产氢细菌Clostridium sp.X9利用酸化汽爆玉米秸秆产氢获得的最大产氢率和玉米秸秆降解率分别为6.4 mmol/g和47.8%.液相代谢末端产物主要为丁酸、乙酸和乙醇.     

离子液体体系下的玉米秸秆降解条件

在离子液体体系下,采用HCl作为催化剂对玉米秸秆进行降解.研究了降解条件(催化剂体积分数、反应温度、反应时间)对玉米秸秆降解过程的影响,确定适宜降解条件为催化剂体积分数7.4%,反应温度85℃,反应时间2.5h.在此条件下,得到的玉米秸秆的降解率为65.8%;在工艺参数相同的条件下,离子液体体系下玉米秸秆的降解率比水体系下玉米秸秆的降解率提高了48.7%.利用SEM分析最优降解参数下固体产物的结构特征,结果表明,离子液体体系降解下产物中纤维素的聚合度降低.红外分析结果表明,离子液体体系与水体系下玉米秸秆降解的剩余物结构基本一致.     

火龙果色素在不同体积分数乙醇溶液中的稳定性

为研究火龙果色素在不同体积分数的乙醇溶液中的稳定性,以吸光度变化为指标,探讨火龙果色素在pH 5.0时,不同乙醇体积分数在不同温度条件下的稳定性.结果表明:乙醇不影响火龙果色素的紫外可见吸收光谱.在40℃和80℃时,火龙果色素降解符合一级反应,其降解速率常数k随着乙醇体积分数的升高而增大,其稳定性降低;而在4℃时,火龙果色素在乙醇溶液中的稳定性较好,其中在体积分数为0、16％、30％的乙醇溶液中稳定性较在体积分数为60％的乙醇溶液中好.此研究结果为含醇火龙果饮料的稳定性提供参考依据.     

鸡冠中透明质酸提取工艺条件的研究

以新鲜公鸡冠为原料对透明质酸的提取方法进行研究.以透明质酸得率为指标,确定采用乙醇处理为最佳方法,选择乙醇体积分数、料液比、提取时间为影响因素,通过单因素和正交试验确定了透明质酸的最佳提取条件:透明质酸提取液与乙醇体积比为1∶2;乙醇体积分数为85％;提取时间为26 h,得到该工艺条件下制备的透明质酸得率为4.84％.通过紫外光谱法检测,显示该提取物质与标准品峰形位置一致,确定该提取物质是透明质酸.     

秸秆类生物质成型燃料氧化过程特性

对玉米秸秆颗粒在不同升温速率和不同氧体积分数下进行热重实验和对照实验,了解外界因素对玉米秸杆颗粒表观质量增加的影响程度以及分析颗粒质量增加的主要原因,同时对不同升温速率和不同氧体积分数下玉米秸秆颗粒氧化反应特征温度的变化规律进行分析。研究结果表明:生物质颗粒与氧的吸附作用是导致颗粒质量增加的主导因素;随着升温速率的增大,玉米秸秆颗粒氧化反应总区间延长,干燥峰值温度θ1、临界温度θ2、着火温度θ4和最大质量损失峰值温度θ5逐渐增大,吸附峰值温度θ3逐渐减小;随着氧体积分数的提高,玉米秸秆颗粒氧化反应总区间缩短,干燥峰值温度θ1保持不变,临界温度θ2先降低再保持不变,吸附峰值温度θ3先降低再上升,着火温度θ4和最大质量损失峰峰值温度θ5随氧体积分数的增加而降低。     

甘蔗渣乙醇化预处理方法比较

用稀硫酸、氢氧化钠及超声波辅助碱法对甘蔗渣进行乙醇化预处理,研究酸、碱的质量分数、温度、时间、质量浓度对甘蔗渣预处理的影响.在硫酸质量分数为0.8%、质量浓度为1∶25（g/mL）、温度为135 ℃ 的条件下反应4 min,经酶水解后糖质量分数为17.81%（g/g）;在氢氧化钠质量分数为9%、质量浓度为1∶8（g/mL）、温度为40 ℃的条件下反应15 min,经酶水解后糖质量分数为14.50%（g/g）;超声波能够强化甘蔗渣碱预处理,处理液经酶水解后的糖质量分数达18.65%（g/g）.     

用改进的酚-氯仿法提取榕小蜂基因组DNA及SRAP分析

以传粉榕小蜂为材料,用改进的酚-氯仿法对不同保存条件下的样品提取基因组DNA,并进行分光光度、琼脂糖凝胶电泳、SRAP扩增等方法的鉴定.结果表明:改进的酚-氯仿法均可从4种保存条件下的样品中提取出DNA,新鲜样品和体积分数95％乙醇固定样品提取效果比其他2组提取效果好.选择体积分数95％乙醇固定所提取的DNA为模板进行...     

浸制条件对黑米酒中黄酮物质和色素含量的影响

以黑米为材料,设计乙醇体积分数、乙醇酸碱度和浸制时间3个因素,在3个不同水平上进行黑米酒的浸制实验,分析比较了黑米酒的黄酮和色素含量,结果表明,3因素中,对黄酮含量影响效应为浸提时间＞乙醇体积分数＞乙醇酸碱度,而对色素含量影响效效应则为乙醇酸碱度＞乙醇体积分数＞浸提时间;乙醇的体积分数为40％－60％、酸碱度pH4有利于黄酮和色素的浸出及色泽的改善;3d的浸提时间可最大限度溶解黄酮物质,且对黑米色素溶解较好。     

大蒜提取物中总酚含量及其抗氧化活性研究

分别以水、体积分数为50%的乙醇、加酶水和加酶的体积分数为50%的乙醇为溶剂,采用超声波提取大蒜,用Folin-Ciocalteu法测定提取物中总酚含量,研究提取物对DPPH.、.OH和O2的清除能力.实验结果表明:提取剂水、体积分数为50%的乙醇、加酶水和加酶的体积分数为50%的乙醇的超声波在100 g大蒜的提取物中总酚含量依次为112.7、102.4、171.1和130.8 mg.4种提取物对DPPH.、.OH和O2均具有较强的清除能力,表明其均具有较强的抗氧化活性.大蒜提取物抗氧化活性与其总酚含量呈明显的量效关系.     

乙醇-汽油燃料汽油机非常规污染物的排放特性

以90#无铅汽油为基础油，按照体积分数5％、10％、15％和20％的甲基叔丁基醚-汽油混合燃料中的氧含量，配制出相应氧含量的乙醇-汽油混合燃料．利用气相色谱技术，分析研究了电喷汽油机燃用不同掺混比乙醇-汽油混合燃料时的非常规排放特性，以及三效催化器对其的净化效率．研究结果表明，在不改变汽油机任何参数的情况下，随着乙醇掺混比的增大，苯的排放量明显降低，尤其当乙醇体积分数为9．826％时，最大降幅接近50％；同时对甲醛排放也有改善作用，但排气中的乙醛和未燃乙醇浓度却相应增加．三效催化器对苯和甲醛的净化效率较高，其中苯的平均净化效率为87％，催化后排气中未检测出甲醛，而对乙醛和乙醇的净化效率相对较低.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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