CONTROLLING DARKENING REACTIONS DURING MECHANICAL PULPING WITH ADDITIVES - A POSSIBLE APPROACH TO IMPROVING BRIGHTNESS AND BLEACHABILITY

The first part of this paper summarizes relevant literature information, which rationalizes our selection of chemicals. The second part reports some preliminary screening results. We have investigated a wide range of reagents, chosen for their different chemistries and divided into seven classes: (1)reducing agents, (2) reduced sulfur compounds, (3)hydrogen donors, (4) antioxidants and radical scavengers, (5) nucleophiles, (6) chelating agents,and (7) oxidizing bleaching agents. It is noted that some chemical reagents fall into more than one class.The obtained results will be discussed with respect to the effectiveness of each class.     

Biomedical Application of Laser

INTRODUCTIONLasershaverevolutionizedresearchanddevelopmentinmedicineanddentistry .Theyhaveledtode velopmentandproductionofmanynewproducts .Laserapplicationsindiagnosis,treatmentandsurgeryareenormousandhaveledtospeedyandmoreefficientresults,aswellasbetterandquickerhealingProcesses.Theapplicationscouldbeclassifiedintermsofareasofusesorintermsofinstruments/products.Inthispa per,discussionswillnotbegroupedinaparticularfashion ,butwi1lbeonspecificapplications .Alotofin formationontheseapplica…     

跨国营销道德状况及影响因素分析

跨国营销道德是用来判定跨国营销活动正确与否的道德标准。文章从两个方面分析了跨国营销的道德问题：一是违反公司及行业道德规范的行为。包括营销方面的隐瞒和欺诈、胁迫和腐败行为及逃避纳税义务等；二是跨文化价值观冲突引起的道德困境，突出表现为母国和东道国在法律和规范上存在的冲突。制约跨国营销道德性决策的因素有很多，可概括为外部因素与内部因素两大类。要提高跨国营销道德水准，防止不道德的营销行为，必须同时从内外两方面着手。     

用小角x光散射研究超临界流体抗溶剂过程中聚苯乙烯链尺寸和构象变化

利用北京同步辐射小角x光散射实验站，对超临界流体的抗溶剂过程中，高分子的构象变化进行了初步的研究。实验表明，在不断加入抗溶剂的过程中，高分子链发生了以伸展规线团郑曲到蜷缩球体的转变。     

The genome of Laccaria bicolor provides insights into mycorrhizal symbiosis

Mycorrhizal symbioses--the union of roots and soil fungi--are universal in terrestrial ecosystems and may have been fundamental to land colonization by plants. Boreal, temperate and montane forests all depend on ectomycorrhizae. Identification of the primary factors that regulate symbiotic development and metabolic activity will therefore open the door to understanding the role of ectomycorrhizae in plant development and physiology, allowing the full ecological significance of this symbiosis to be explored. Here we report the genome sequence of the ectomycorrhizal basidiomycete Laccaria bicolor (Fig. 1) and highlight gene sets involved in rhizosphere colonization and symbiosis. This 65-megabase genome assembly contains approximately 20,000 predicted protein-encoding genes and a very large number of transposons and repeated sequences. We detected unexpected genomic features, most notably a battery of effector-type small secreted proteins (SSPs) with unknown function, several of which are only expressed in symbiotic tissues. The most highly expressed SSP accumulates in the proliferating hyphae colonizing the host root. The ectomycorrhizae-specific SSPs probably have a decisive role in the establishment of the symbiosis. The unexpected observation that the genome of L. bicolor lacks carbohydrate-active enzymes involved in degradation of plant cell walls, but maintains the ability to degrade non-plant cell wall polysaccharides, reveals the dual saprotrophic and biotrophic lifestyle of the mycorrhizal fungus that enables it to grow within both soil and living plant roots. The predicted gene inventory of the L. bicolor genome, therefore, points to previously unknown mechanisms of symbiosis operating in biotrophic mycorrhizal fungi. The availability of this genome provides an unparalleled opportunity to develop a deeper understanding of the processes by which symbionts interact with plants within their ecosystem to perform vital functions in the carbon and nitrogen cycles that are fundamental to sustainable plant productivity.     

碳纤维布抗震加固混凝土T型节点试验

根据碳纤维布优良的材料性能,提出了3种基于碳纤维布的节点抗震加固方法.通过6个混凝土T型外节点试件的低周反复加载试验,对所提出的3种节点抗震加固方法进行了检验和对比.试验结果表明:所采用的不同加固方法均能够有效增强节点核心区的抗剪性能,改变节点的剪切破坏模式;不同的加固方法对于节点组合体在滞回特性、延性性能以及承载力等方面抗震性能的改善效果存在各自的特点.     

生物质气化合成二甲醚系统的火用分析

基于生物质串行流化床气化合成二甲醚(DME)系统的Aspen Plus模拟,对系统进行热力学火用分析,研究了气化反应参数与合成反应参数对各子系统和总系统的火用效率影响.研究结果显示:火用损失主要发生在气化子系统中;气化产物氢碳摩尔比在2左右时,系统火用效率可达到最大;液化子系统提高气化合成二甲醚一步反应的有效转化率,降低循环气份额,可有效提高系统火用效率;全系统的火用损失主要是由过程的不可逆性引起的,内部火用损率近80%.对于稻秸气化一步法合成二甲醚系统,适宜的气化温度为750~800℃,水蒸气生物质质量比为0.3;在合成温度为260~280℃,合成压力为4.0~4.5 MPa的条件下,系统的二甲醚产率可达到6.20 mol/kg,火用效率达到51.66%.     

Guaranteed cost control for discrete-time networked control systems with random Markov delays

The guaranteed cost control for a class of uncertain discrete-time networked control systems with random delays is addressed.The sensor-to-controller (S-C) and contraller-to-actuator (C-A) random network-induced delays are modeled as two Markov chains.The focus is on the design of a two-mode-dependent guaranteed cost controller,which depends on both the current S-C delay and the most recently available C-A delay.The resulting closed-loop systems are special jump linear systems.Sufficient conditions for existence of guaranteed cost controller and an upper bound of cost function are established based on stochastic Lyapunov-Krasovakii functions and linear matrix inequality (LMI) approach.A simulation example illustrates the effectiveness of the proposed method.     

抗战时期云南民族文化精神基本层面论析——从旅滇作家和马子华的散文说起

抗战时期,包括闻一多、朱自清等旅滇作家及马子华等本土作家都留下了不少的散文篇什,对云南和云南人的精神风貌、生活状况描绘颇多。通过对这些文章的分析,可以从中解读出云南民族文化精神的基本层面——强烈的家国(园)意识、坚韧的反抗精神、顽强的生存信念、迭变的狭隘思想,而这有助于人们更好地把握和领会抗战时期云南文化的多样性特质。