SMA路面中各种纤维应用现状及发展趋势

制造SMA一般都采用纤维作为稳定剂,使用的纤维主要有木质素纤维、矿物纤维、聚合物化学纤维3大类．纤维具有加筋、分散、吸附沥青、稳定、增粘等作用,对防止SMA沥青析漏的功效较好．从施工性能、使用性能、成本等方面阐述了以上3种纤维的应用现状及发展趋势．     

Metal-insulator-semiconductor optoelectronic fibres

The combination of conductors, semiconductors and insulators with well-defined geometries and at prescribed length scales, while forming intimate interfaces, is essential in most functional electronic and optoelectronic devices. These are typically produced using a variety of elaborate wafer-based processes, which allow for small features, but are restricted to planar geometries and limited coverage area. In contrast, the technique of fibre drawing from a preformed reel or tube is simpler and yields extended lengths of highly uniform fibres with well-controlled geometries and good optical transport characteristics. So far, this technique has been restricted to particular materials and larger features. Here we report on the design, fabrication and characterization of fibres made of conducting, semiconducting and insulating materials in intimate contact and in a variety of geometries. We demonstrate that this approach can be used to construct a tunable fibre photodetector comprising an amorphous semiconductor core contacted by metallic microwires, and surrounded by a cylindrical-shell resonant optical cavity. Such a fibre is sensitive to illumination along its entire length (tens of meters), thus forming a photodetecting element of dimensionality one. We also construct a grid of such fibres that can identify the location of an illumination point. The advantage of this type of photodetector array is that it needs a number of elements of only order N, in contrast to the conventional order N2 for detector arrays made of photodetecting elements of dimensionality zero.     

水介质的化学性质和流动方式对深部碎屑岩储层成岩作用的影响

对东营凹陷下第三系深部碎屑岩储层成岩作用的影响因素进行了研究 ,结果表明 ,有机无机化学反应提供的酸性水介质环境和异常压力带流体的循环热对流是影响和控制深部碎屑岩储层成岩作用的重要因素。有机质热演化、粘土矿物转化、硫酸盐热化学氧化还原反应、油田水化学性质和烃类物质进入储层等因素引起地层水介质化学性质的变化 ,这严重影响了深部碎屑岩储层的成岩作用。循环热对流是深部储层流体的主要流动方式 ,它控制着自生矿物在砂层中的析出位置和次生孔隙的分布特征     

Evidence for non-selective preservation of organic matter in sinking marine particles

The sinking of particulate organic matter from ocean surface waters transports carbon to the ocean interior, where almost all is then recycled. The unrecycled fraction of this organic matter can become buried in ocean sediments, thus sequestering carbon and so influencing atmospheric carbon dioxide concentrations. The processes controlling the extensive biodegradation of sinking particles remain unclear, partly because of the difficulty in resolving the composition of the residual organic matter at depth with existing chromatographic techniques. Here, using solid-state 13C NMR spectroscopy, we characterize the chemical structure of organic carbon in both surface plankton and sinking particulate matter from the Pacific Ocean and the Arabian Sea. We found that minimal changes occur in bulk organic composition, despite extensive (>98%) biodegradation, and that amino-acid-like material predominates throughout the water column in both regions. The compositional similarity between phytoplankton biomass and the small remnant of organic matter reaching the ocean interior indicates that the formation of unusual biochemicals, either by chemical recombination or microbial biosynthesis, is not the main process controlling the preservation of particulate organic carbon within the water column at these two sites. We suggest instead that organic matter might be protected from degradation by the inorganic matrix of sinking particles.     

Microstructure and Element Composition of Shell Plates of Liolophura japonica

The microstructure characteristics of shell plates of chiton Liolophura japonica Lischke were analyzed using environmental scanning electron microscopy (ESEM). The results show that the internal structure of the shell plate of chiton Liolophura japonica is composed of seven calcium layers which were crossed lamellar crystallites, homogeneous structure, granular crystallites, and trabecular type crystallites. The element compositions of shell plates were analyzed using X-ray photoelectron spectroscopy (XPS). The results determined by XPS show that the surface chemical states of various layers are different. There are 13 elements (Na, O, N, C, S, P, Ca, Cl, Si, Al, K, Fe, Mg) on the shell plate of chiton L. japonica. Among the 13 elements, 11 are on the outside pigment layer except K and S. Among seven layers of shell plate, there is the largest quantity of elements on the outside pigment layer, and the least quantity of elements is on layer C (Articulamentum auctorum). There are 7 elements on the layer C (Articulamentum auctorum). Besides calcium carbonate, there are some inorganic compounds on the shell plate, such as NaCl, MgO, Al2O3, silicate, sulfate and phosphate. There are some organic chemical components, such as carbohydrate, organic sulfide, and organic nitride on the shell plates.     

羊毛纤维的形态弱节及特征

对羊毛纤维弱节的几何形态特征，采用SEM观察进行了分类定义和表征。实际观察发现羊毛的弱节有纤维细颈和形态结构缺陷二类，其中形态结构缺陷主要是天然生长和人为加工中的畸变点和损伤点。弱节的几何长度为纤维直径的2－4倍，且弱节越多，纤维直径离散越大。同时分析了羊毛形态弱节的主要成因。     

成岩作用及阶段对碎屑岩储层孔隙演化的控制

碎屑岩储层孔隙演化受有机-无机成岩作用的影响,在埋藏成岩阶段,有机质成熟过程中脱羧作用产生的有机酸对碎屑岩中的方解石、长石等溶蚀所形成的次生扎隙,是深部储层中高孔渗段发育的重要原因,随埋深增加,成岩阶段由早-晚发展,有机质由未成熟-成熟演化,在此期间,储层孔隙经历了消亡与新生的发展过程。在同一盆地中,不同层位储层经历的最大埋深如果相近,所处成岩阶段也相近,其孔隙演化史亦趋于相似;反之,同一层位的储层所处的最大埋深不同,成岩阶段不同,其孔隙特征也就不同。     

维尼纶纤维增强石膏基复合材料力学性能研究

研究了石膏基复合材料的结构、耐水机理和物理力学性能.结合弯曲载荷变形曲线,分析了维尼纶纤维增强石膏基复合材料的断裂机理;利用扫描电子显微镜,分析了复合材料界面性能.结果表明:石膏基复合材料实现了单一的结晶到晶胶共生的结构转变,材料的强度和耐水性得到改善;维尼纶纤维能提高复合材料的抗折强度、断裂能、断裂韧性和冲击韧度;维尼纶纤维增强石膏基复合材料断裂过程可分为3个阶段:基体断裂、纤维脱粘和纤维拔出;纤维和基体间界面结合强度较弱.     

Annealing-induced interfacial toughening using a molecular nanolayer

Self-assembled molecular nanolayers (MNLs) composed of short organic chains and terminated with desired functional groups are attractive for modifying surface properties for a variety of applications. For example, organosilane MNLs are used as lubricants, in nanolithography, for corrosion protection and in the crystallization of biominerals. Recent work has explored uses of MNLs at thin-film interfaces, both as active components in molecular devices, and as passive layers, inhibiting interfacial diffusion, promoting adhesion and toughening brittle nanoporous structures. The relatively low stability of MNLs on surfaces at temperatures above 350-400 degrees C (refs 12, 13), as a result of desorption or degradation, limits the use of surface MNLs in high-temperature applications. Here we harness MNLs at thin-film interfaces at temperatures higher than the MNL desorption temperature to fortify copper-dielectric interfaces relevant to wiring in micro- and nano-electronic devices. Annealing Cu/MNL/SiO2 structures at 400-700 degrees C results in interfaces that are five times tougher than pristine Cu/SiO2 structures, yielding values exceeding approximately 20 J m(-2). Previously, similarly high toughness values have only been obtained using micrometre-thick interfacial layers. Electron spectroscopy of fracture surfaces and density functional theory modelling of molecular stretching and fracture show that toughening arises from thermally activated interfacial siloxane bridging that enables the MNL to be strongly linked to both the adjacent layers at the interface, and suppresses MNL desorption. We anticipate that our findings will open up opportunities for molecular-level tailoring of a variety of interfacial properties, at processing temperatures higher than previously envisaged, for applications where microlayers are not a viable option-such as in nanodevices or in thermally resistant molecular-inorganic hybrid devices.     

Synthesis of fast myosin induced by fast ectopic innervation of rat soleus muscle is restricted to the ectopic endplate region

Skeletal muscle fibres, long multinucleated cells, arise by fusion of mononucleated myoblasts to form a myotube that matures into the adult fibre. The two major types of mature fibre, fast and slow fibres, differ physiologically in their rate of isotonic shortening. At the molecular level these type-specific physiological properties are ascribed to different isoforms of myosin, a major protein involved in shortening. Differentiation of fast and slow fibres seems to be under the control of motoneurones, and mature fibres are innervated by only one motoneurone. When rat soleus muscle (SOL, a slow muscle) is dually innervated with a fast nerve, it acquires some properties of a fast muscle, that is, low sensitivity to caffeine and high glycogen content. We report here that in dually innervated soleus muscle the foreign fast nerve induces synthesis of fast isoforms of myosin, but only in the segment of the muscle fibre that is close to the foreign endplate. The localized influence of the nerve endplates suggest that factors controlling the phenotypic expression of the muscle fibre have a short range of activity.     

导电纤维的回顾与展望

本文综述了导电纤维的发展过程,并就导电纤维的发展方向进行了展望。早在五十年代,就开始了对合成纤维抗静电处理方法的研究,当时产品的性能尚不甚完善。七十年代发展的导电成份复合型导电纤维,是将含导电微粒的高聚物与成纤聚合物一起复合纺丝。所得纤维的性能良好。在进一步研究的基础上,导电成份覆盖型导电纤维也被开发。本文介绍了国内外研究较为深入的三种制备导电成份覆盖型导电纤维的方法。其一是在纤维表面形成聚毗咯层;其二为在纤维表面镀复金属层;其三在纤维表面发生化学反应,形成金属化合物覆盖层。实践中发现上述三种方法制备的导电纤维各有千秋。最后本文对导电纤维的发展方向作了展望,指出结构型的导电聚合物是导电纤维的发展方向。     

活性白土性质及若干应用探讨

活性白土是膨润土经硫酸活化处理而得。酸处理条件明显地影响了活性白土的化学组成和结构状态。对其控制并制备化学组成和结构都适宜的活性白土,能与有机胺类化合物和硅烷偶联剂及结晶紫内脂等有机分子作用,发生层间吸附、键合、吸电子等作用。应用这些性质,可将粘土矿物制备成橡胶、环氧树脂补强填料及无碳复写纸显色剂。     

Formation of chiral morphologies through selective binding of amino acids to calcite surface steps.

Many living organisms contain biominerals and composites with finely tuned properties, reflecting a remarkable level of control over the nucleation, growth and shape of the constituent crystals. Peptides and proteins play an important role in achieving this control. But the general view that organic molecules affect mineralization through stereochemical recognition, where geometrical and chemical constraints dictate their binding to a mineral, seems difficult to reconcile with a mechanistic understanding, where crystallization is controlled by thermodynamic and kinetic factors. Indeed, traditional crystal growth models emphasize the inhibiting effect of so-called 'modifiers' on surface-step growth, rather than stereochemical matching to newly expressed crystal facets. Here we report in situ atomic force microscope observations and molecular modelling studies of calcite growth in the presence of chiral amino acids that reconcile these two seemingly divergent views. We find that enantiomer-specific binding of the amino acids to those surface-step edges that offer the best geometric and chemical fit changes the step-edge free energies, which in turn results in macroscopic crystal shape modifications. Our results emphasize that the mechanism underlying crystal modification through organic molecules is best understood by considering both stereochemical recognition and the effects of binding on the interfacial energies of the growing crystal.     

Formation of thermally stable alkylidene layers on a catalytically active surface

Materials containing organic-inorganic interfaces usually display a combination of molecular and solid-state properties, which are of interest for applications ranging from chemical sensing to microelectronics and catalysis. Thiols--organic compounds carrying a SH group--are widely used to anchor organic layers to gold surfaces, because gold is catalytically sufficiently active to replace relatively weak S-H bonds with Au-S bonds, yet too inert to attack C-C and C-H bonds in the organic layer. But although several methods of functionalizing the surfaces of semiconductors, oxides and metals are known, it remains difficult to attach a wide range of more complex organic species. Organic layers could, in principle, be formed on the surfaces of metals that are capable of inserting into strong bonds, but such surfaces catalyse the decomposition of organic layers at temperatures above 400 to 600 K, through progressive C-H and C-C bond breaking. Here we report that cycloketones adsorbed on molybdenum carbide, a material known to catalyse a variety of hydrocarbon conversion reactions, transform into surface-bound alkylidenes stable to above 900 K. We expect that this chemistry can be used to create a wide range of exceptionally stable organic layers on molybdenum carbide.     

Study on Properties of Jute Fibres Spun on Ring Spinning System

Jute fibre properties,viz. linear density,mechanical properties,and fibre staple length were analyzed in this paper. Morphology,lignin content,and composition analysis for jute fibres were investigated in order to give further understanding of the fibre properties changing during the chemical treatment and yarn producing processes. The results show that jute properties are greatly changed during the processes of chemical treatment,breaking carding,and finisher carding,whereas slight changes can be found in ...     

Biomineralization process occurring in iron mud of coastal seepage area of Zhoushan Island, Zhejiang province

The biomineralization process of iron oxidizing bacteria and its influence on accumulation of metals were investigated by modern biological observation techniques （i.e., SEM and TEM） and geochemical methods, in coastal area of Zhoushan Island, Zhejiang province where a thick ancient wood layers were buried, Results show that the iron mud samples mainly contain Leptothrix-like sheaths and Gallionella-like stalks, which are known as neutrophilic iron-oxidizing bacteria. These two bacteria are present as obviously different abundance in two sampling sites, which may be regulated by the geochemistry of seepage water. The biomineralization product of iron oxidizing bacteria is ferrihydrite, a poorly ordered iron oxide, and formation of amorphous mineral is affected by the factors of bacteria, minor Si and temperature preventing any further transformation into more crystalline phases. Organic functional groups, extracellular polymers and surface charges can provide favorable nucleation sites or template for formation of iron precipitates on the bacterial surface. The mineralization process of the iron oxidizing bacteria is divided into different stages, i.e., extracellular mineralization, intracellular mineralization and the whole cell mineralization. Furthermore, due to BIOS containing the bacterial organic matter, the accumulation capacity of metals specially Fe and Co is highly increased, suggesting that BIOS exert a degree of controlling in the cycling of metal elements in seepage area.     

塔中地区上奥陶统良里塔格组构造裂缝成岩作用研究

裂缝作为流体活动的通道,对碳酸盐岩储集体的形成、演化及分布起到非常重要的作用。选取塔里木盆地塔中上奥陶统良里塔格组碳酸盐岩构造裂缝为研究目标,开展了岩芯观测和采样工作,运用显微薄片、阴极发光、流体包裹体、荧光测试等分析方法,重点研究了裂缝的形成充填特征,识别出了方解石胶结、重晶石胶结及萤石胶结等成岩作用类型,良里塔格组构造裂缝经历了3期流体充填作用,第一期为浅埋藏大气淡水胶结;第二期为二叠纪末热流体活动的结果;第三期为中-深埋藏阶段流体的充填作用。     

烷基MCM-41复合介孔分子筛的合成

以二甲基二氯硅烷(Dimethyl dichlorosilane,DMCS)、辛基三甲氧基硅烷(Octyltrimethoxysi-lane,C11H26O3Si)和十八烷基三氯硅烷(Octadecyltrichlorosilane,C18H37C13Si)为硅烷化试剂,采用后处理接枝技术对介孔分子筛MCM-4l表面进行烷基化修饰,合成了无机-有机复合材料R-MCM-41(R-烷基),并用XRD、元素分析和FT-lR对复合材料进行了表征。结果表明,有机基团进入了MCM-41孔道。     

香港全风化花岗岩的固结特性

对采自香港地区全风化花岗岩原状土样进行了固结试验研究,结果表明：其先期固结压力及超固结比明显偏大,且先期固结压力在深度上表现出异常现象;在固结压力持续增加的条件下,3种土的压缩系数和固结系数逐步减小,开始减小速率比较大,之后趋于平缓,呈近似负指数关系,但压缩系数的变化幅度比固结系数大;全风化花岗岩由于风化所产生的特殊的物理、化学及矿物成分变化和所具有的结构强度是造成其固结特性的主要原因．     

Wavelength-scalable hollow optical fibres with large photonic bandgaps for CO2 laser transmission

Conventional solid-core optical fibres require highly transparent materials. Such materials have been difficult to identify owing to the fundamental limitations associated with the propagation of light through solids, such as absorption, scattering and nonlinear effects. Hollow optical fibres offer the potential to minimize the dependence of light transmission on fibre material transparency. Here we report on the design and drawing of a hollow optical fibre lined with an interior omnidirectional dielectric mirror. Confinement of light in the hollow core is provided by the large photonic bandgaps established by the multiple alternating submicrometre-thick layers of a high-refractive-index glass and a low-refractive-index polymer. The fundamental and high-order transmission windows are determined by the layer dimensions and can be scaled from 0.75 to 10.6 micro m in wavelength. Tens of metres of hollow photonic bandgap fibres for transmission of carbon dioxide laser light at 10.6 micro m wavelength were drawn. The transmission losses are found to be less than 1.0 dB m(-1), orders of magnitude lower than those of the intrinsic fibre material, thus demonstrating that low attenuation can be achieved through structural design rather than high-transparency material selection.