木质纤维原料预处理技术

木质纤维原料作为一种可转化为液体燃料的可再生资源,其转化利用已成为必然趋势,而木质纤维原料的预处理是利用木质生物资源生产乙醇的一个重要环节。文章阐述了木质纤维原料的常用预处理技术,并对其发展前景作了展望。     

木质纤维原料预处理技术的研究进展

木质纤维是地球上最丰富的可再生资源,木质纤维资源的转化利用已成为必然趋势,而在木质纤维功能转化中预处理技术起着非常重要的作用。文章阐述了木质纤维原料的常用预处理技术,并对其发展前景作了展望。     

木质纤维生物质热化学转化预处理技术研究进展

主要介绍了木质纤维生物质原料的组分,综述了物理法、物理-化学法和化学法3种预处理方式在木质纤维生物质热化学转化中应用的研究进展,并阐述了各预处理方式对原料和转化产物的影响,指出它们在应用方面的缺憾及限制,最后对木质纤维生物质的预处理方式进行了展望.     

爆炸地震波的冲击特征分析

研究了爆炸地震波的冲击特性。根据实验结果,对质点振动时间历史在强震阶段的不规则变化进行了讨论,发现Fourier谱不能描述强震脉冲作用的特征。研究结果对爆炸地震的结构安全性分析具有一定的指导价值。     

爆炸波膨化法对木质纤维材料形态结构的影响

采用爆炸波膨化法对速生杨木片进行处理,用扫描电镜观测分析爆炸波膨化处理前后杨木片的组织形态变化。实验结果表明:未经爆炸波处理的原始状态的杨木(片)材料,其纤维组织的扫描显微图像呈致密的导管状分布,而且导管间纵向平行排列;经爆炸波处理后,杨木材料的扫描显微图像呈现无序排列的纤维形态,纤维组织的致密度大大降低,这将有利于增强液体对木质纤维组织的浸渍、润胀等作用。     

纤维素可及性对木质纤维酶水解影响的研究进展

纤维素的可及性是纤维原料中与纤维素酶结合且能够被酶处理的结合位点量,与纤维原料中的粒径和孔隙度有关,纤维素的可及性是影响纤维素酶水解的关键因素。综述了当前纤维素可及性的测定方法,包括氮吸附法、水银压入法、溶质排斥法、蛋白质吸附法、Simons法等,总结了通过提高纤维素可及性来实现高效生物转化的预处理技术,并给出当前生物乙醇转化的可能研究方向。     

木质纤维原料酶水解研究进展

木质纤维原料酶水解是利用木质纤维原料生产燃料酒精的关键步骤之一。作者对纤维素酶及其水解木质纤维原料作用机制、纤维素酶的生产、木质纤维原料酶水解的影响因素和木质纤维原料酶水解动力学作了全面综述,并对提高木质纤维原料酶水解效率和降低水解成本的途径进行了讨论。     

木质纤维原料的热化学液化

用热化学方法 ,可以将木质纤维原料液化成为烃、醇、酚、羧酸等多种有机物以及一些无机物。在所有的木质纤维原料液化手段中 ,热化学液化是最容易实现、同时又最经济的方法。综述了木质纤维原料热化学液化反应机理及实现木质纤维原料液化的工艺进展。将木质纤维原料转化成液体燃料或化工原料 ,对充分利用自然界中可再生资源 ,降低燃烧石油造成的环境污染 ,具有重要的意义     

有机溶剂自催化和协同预处理促进木质纤维原料酶解研究进展

木质纤维原料资源储量丰富且可再生,适当的预处理可打破纤维原料细胞壁的天然抗降解屏障,促使其在后续加工中有效转化为低聚糖或可发酵糖,用于高效制备生物乙醇。有机溶剂预处理是有效的预处理方法之一,在提高酶解效率的同时可有效分离木质素,实现纤维原料各组分的高效利用。根据是否添加催化剂,有机溶剂预处理可分为自催化预处理和催化剂-有机溶剂协同预处理2种方式。木质素是限制木质纤维原料酶解的重要因素之一,本文简单介绍了有机溶剂种类、催化剂类型对木质素脱除的影响,并概括性探讨了有机溶剂和催化剂协同的反应机理。     

Analysis method of explosive electromagnetic radiation energy

The energy of electromagnetic radiation from explosions is coupled to electronic equipment circuits, disrupting the initiation sequence or causing failure in an increasing number of cases, which seriously affects the stability of weapon systems. There is a significant difference between the characteristics of the explosive electromagnetic radiation signals and modulated electromagnetic signals. The electric field intensity and signal power cannot directly represent the magnitude of the explosive electromagnetic radiation energy, and traditional electromagnetic signal analysis methods are unsuitable for explosion electromagnetic signal analysis. To solve this problem, the mechanism of explosive electromagnetic radiation was first analyzed. Through verification experiments of the explosion electromagnetic intensity and temperature, it was concluded that there is a strong correlation between the explosion plasma temperature and electromagnetic intensity. The temperature of the explosive plasma is derived based on the measured surface temperature of the explosive fireball, a functional relationship is established between the energy of the explosive plasma and the temperature of the plasma, and plasma energy is introduced as a parameter for electric field intensity correction. The interference signal analysis method based on eye diagram is used to calibrate the electromagnetic radiation damage ability, achieving quantitative analysis of the interference degree of electromagnetic radiation energy on the signal, and providing a new approach for the analysis of explosive electromagnetic radiation energy.     

木质纤维素材料预处理研究进展

介绍了木质纤维素材料的抗降解屏障、影响预处理效果的因素、高效预处理的评价标准,并就目前研究较多的酸法、碱法、有机溶剂、蒸汽爆破几种木质纤维素材料预处理技术的相关研究情况进行了综述。最后对预处理技术的发展方向予以展望。     

Toxicity tolerance of Fusarium oxysporum towards inhibitory compounds formed during pretreatment of lignocellulosic materials

BACKGROUND: During the pretreatment of lignocellulosic materials, molecules such as carboxylic acids, furan derivatives and phenolic compounds, which inhibit the growth and ethanol fermentation by bacteria, fungi and yeasts, are produced. The present work determines the tolerance levels of the C5, C6 fermenting fungus Fusarium oxysporum, towards individual model inhibitory compounds on aerobic growth, on lignocellulolytic activities and on fermentative performance. RESULTS During the growth stage, maximum biomass production was more affected than the specific growth rate by the presence of inhibitors. The presence of high concentrations of inhibitors resulted, in most cases, in prolongation of the lag phase. The fermentative performance of F. oxysporum was significantly inhibited by carboxylic acids, while the lignocellulolytic activities were affected to a lesser extent. CONCLUSION: The toxicity tolerance of fF. oxysporum was high enough for aerobic growth in the presence of significant concentrations of inhibitors, which in most cases were higher than those generated from various treatments of lignocellulosic materials, while its fermentative performance was relatively more affected by the presence of inhibitors. The decrease of ethanol production in the presence of weak organic acids could be the main obstacle to the application of F. oxysporum in large‐scale bioconversion processes of hydrolysates containing inhibitors. Copyright © 2010 Society of Chemical Industry     

煤粉制备系统火灾爆炸指数安全评价方法探讨

介绍了水泥熟料生产线煤粉制备系统安全评价采用的火灾爆炸指数安全评价方法;深入总结了该方法的运用程序、适用条件以及相关参数的选取和计算方法;并以2000t/d生产线的煤粉制备系统为例进行了实例分析计算。在此基础上,提出了在煤粉制备系统工艺设计上一般可采取的安全技术措施与对策,且在一定程度上还探讨了煤粉制备系统安全评价的规范化模式。     

一种用紫外光谱测定混合糖含量的新方法

提出一种用紫外光谱测定样品中混合糖含量的方法。其原理是基于样品中的糖经浓硫酸处理后生成有紫外吸收的糠醛和羟甲基糠醛,进行紫外波长吸收测定;通过化学计量学软件,根据一组已知糖浓度标准样品的多波长光谱和所对应组成浓度之间的数学关系,建立校正模型。将未知样品的紫外光谱信息输入校正模型即可预测其组成中糖的含量。本方法无需使用有机试剂,操作简便,可以测定样品中戊糖、己糖和总糖的含量,适合于木质生物质炼制研究中溶解性糖类组分的分析。     

熔铸炸药研究现状与发展趋势

熔铸炸药是目前战斗部最主要的装药方式之一,但是现有以TNT为载体的熔铸炸药配方在能量、安全性、装药质量和力学性能等方面存在明显缺陷。本文详细综述了熔铸炸药连续相、高能量密度材料、综合降感技术、流变性研究和装药工艺5个方面国内外的研究现状,特别是归纳了以NTO、DNTF等为代表的新型含能材料的应用情况,提出了熔铸炸药在新型载体物质、高能钝感单质炸药、共晶炸药、功能助剂、高固相含量熔铸体系装药工艺等方面未来的主要发展方向。     

压痕法研究ZrO2层状复合陶瓷的抗热震性

用压痕法测试了单层和层状两种ZrO2陶瓷材料的抗热震性能.研究结果表明ZrO2层状复合陶瓷的临界热震温差△Tc=400℃,比ZrO2单层陶瓷高出150℃左右,同时还表现出其△Tc与陶瓷厚度无关的优异性质.现场试验结果也证明,ZrO2层状复合陶瓷抵抗1500℃冷热骤变的能力优于ZrO2单层陶瓷.研究认为,界面压应力作用部分或全部抵消了热冲击应力,使裂纹在界面处发生偏转,提高了材料的断裂能和断裂功,导致材料的抗热震性提高.     

Method for studying the decomposition kinetics of an explosive behind a SW front

An experimental procedure is proposed that allows simultaneous measurements of time dependences of pressure and density in the same experiment. The dependences can be used to determine the variation in the phase composition of the material behind the shock front in the coordinates pressure-volume and to calculate the time variation in the degree of decomposition of the explosive after the passage of the shock front. Dependences of the formal kinetics of postshock decomposition were obtained for an explosive composition based on sensitized HMX. __________ Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 6, pp. 99–106, November–December, 2008.     

On the Jones-Wilkins-Lee equation of state for high explosive products

The Jones-Wilkins-Lee (JWL) model is a widely used Equation Of State (EOS) in the literature to model high explosive products. It is based on exponentially decaying isentropes in the pressure-volume diagram, completed by an additional term meant to recover an ideal-gas behavior for large expansions where exponential terms are negligible. A step-by-step analysis of the EOS is proposed. Starting from the main isentrope, the constant Grüneisen, and constant isochoric heat capacity, the JWL expressions of pressure, temperature, sound speed, specific internal energy, specific entropy and specific enthalpy are derived. For a specific set of JWL parameters meant to model HMX products, various thermodynamic fields are investigated in pressure–volume and temperature–volume planes. The positivity of pressure and temperature, the convexity, the thermodynamic stability, and the monotonicity along an Hugoniot are investigated in order to characterize the JWL domain of validity. For each of these constraints, different regions of validity are found. Besides presenting a study of the JWL model and its limits, this work also provides a standalone presentation and derivation containing the necessary materials for the understanding and for the use of the JWL EOS in reactive hydrodynamic simulations of condensed phase explosives.     

用声发射监测陶瓷材料的热震损伤

介绍了声发射技术的基本原理,用声发射技术监测了莫来石－钛酸铝陶瓷材料急冷时热震损伤强度衰减及裂纹的扩展过程,结果表明：由热应力引起的微裂纹稳态扩展和失稳扩展的声发射特性与该试样热震损伤后的残余强度变化趋势是一致的。