巯基棉富集分离-原子荧光光谱法测定高碳高硫地质样品中痕量硒

氢化物发生-原子荧光光谱法（HG-AFS）应用于测定地质样品中的痕量硒具有较高的灵敏度,但复杂的基质仍会增加分析难度,尤其是富含有机质样品与硫化物样品中的有机碳、复杂配合物和共存离子等带来的干扰,故样品前处理十分重要。采用常规的巯基棉（thiol cotton fibre,TCF）富集分离方法处理富含有机质样品与硫化物样品时,常会出现回收率不稳定、TCF过早饱和的现象。因此,本文针对富含有机质样品,使用双TCF柱法,通过两次吸附可以有效减少有机质的干扰;针对硫化物样品,可通过增加TCF的用量或者减少称样量来提高硒的回收率。标准物质和实际样品的测定结果表明优化的方法可满足分析要求,对富有机质样品,硒的回收率大于95.1%±0.37%;对硫化物样品,硒的回收率大于95.5%±1.92%。同时,研究也表明,采用微波消解处理样品,能够有效地避免硒在消解过程中的损失。改进后的方法提升了富集分离效果,适用于有机质和硫化物地质样品中的痕量硒（ng/g~μg/g级）分析要求。     

鲤鱼神经垂体的超微结构研究

经电子显微镜观察，提出鲤鱼（Ｃｙｐｉｎｕｓｃａｒｐｉｏ）神经垂体（ｎｅｕｒｏｈｙｐｏｐｈｙｓｉｓ）由有髓神经分泌纤维和三种无髓神经分泌纤维（Ａ．Ｂ．Ｃ）以及垂体细胞和毛细血管组成。神经分泌纤维与垂体细胞之间存在着突触联系，神经分泌纤维之间只有细胞间连接（桥粒）。在神经垂体组织中还存在Ⅰ型和Ⅱ型两种结构与功能不同的垂体细胞，另外在血管间道内观察到了很少见的特殊空泡结构     

Comprehensive research on self phase modulation based optical delay systems

This paper comprehensively investigates the properties of self phase modulation based optical delay systems consisting of dispersion compensation fibre and highly nonlinear fibres. It researches into the impacts of power level launched into highly nonlinear fibres, conversion wavelength, dispersion slope, modulation format and optical filter bandwidth on the overall performance of optical delay systems. The results reveal that, if the power launched into highly nonlinear fibres is fixed, the time delay generally varies linearly with the conversion wavelength, but jumps intermittently at some conversion wavelengths. However, the time delay varies semi-periodically with the power launched into highly nonlinear fibres. The dispersion slope of highly nonlinear fibres has significant influence on the time delay, especially for the negative dispersion slope. The time delay differs with modulation formats due to the different combined interaction of nonlinearity and dispersion in fibres. The bandwidth of the optical filters also greatly affects the time delay because it determines the bandwidth of the passed signal in the self phase modulation based time delay systems. The output signal quality of the overall time delay systems depends on the conversion wavelength and input power level. The optimisation of the power level and conversion wavelength to provide the best output signal quality is made at the end of this paper.     

Bearing capacity performance of soft cohesive soil treated by kenaf limited life geotextile

Abstract

This article presents the performance of the short-term bearing capacity on soft clay soil treated by Kenaf geotextile under vertical loading via a small-scale modelling test at unit gravity. The ground model was formulated by consolidating kaolin in a rigid testing compartment. In the loading test, the strip footing was represented by a rigid footing. For the treated case, a series of tests were performed to examine the effects of the burial depth of the Kenaf geotextile on the bearing capacity of the soft soil. The Kenaf geotextile was laid beneath the rigid footing (at the ground surface) and at 50, 75 and 100?mm depth from the soil surface. All the measured results of the Kenaf geotextile treated ground were compared with the untreated ground. The incorporation of Kenaf fibre geotextile was observed to enhance the bearing capacity of soft cohesive clay up to 281% depending upon the depth of the installed geotextile. The geotextile at the surface provided the highest bearing capacity and sustained the highest displacement at failure. The outcome of this research will promote the use of natural fibre geotextiles as sustainable earth reinforcement in temporary earthwork applications.     

均布荷载下钢纤维混凝土叠合梁抗剪性能试验研究

本文通过11根叠合梁的试验,分析了均布荷载作用下钢纤维混凝土叠合梁的抗剪性能,提出了无腹筋和配箍筋钢纤维混凝土叠合梁斜截面受剪承载力的计算公式。研究结果表明,钢纤维的掺入改善了叠合梁的抗剪性能,提高了斜截面受剪承载力。     

A Method for Analyzing the Self-Supported Earth-Retaining Structure Using Stabilizing Piles

The self-supported earth-retaining structure using stabilizing piles (SSR is used from here) has the advantages of less deformation and less internal force compared with conventional cantilever retaining structure. It is easier to conduct the excavation when SSR is used for an excavation instead of using braced excavation with struts. The SSR is better than other methods to the 10 m shallow excavation depth in terms of economical and constructional efficiency when the ground is not very soft. However, this SSR method lacks a theoretical basis in terms of geotechnical engineering. The objective of this study is to develop a method of analysis by laboratory model tests. A variety of model tests were performed in order to analyze the behavior of SSR and the ground, and to measure the stress acting on stabilizing piles relative to excavation steps and earth pressures on the wall. The analysis reveals the failure mechanism of a wedge and then suggests a method for calculating a virtual supported point. These findings were incorporated into a method for analyzing retaining wall, stabilizing piles, and beams connecting two structures. Future research is geared toward developing a design program that uses the analytical methodology for this SSR.     

XO螯合形成纤维分离富集微量锆铪性能的研究

本文采用先螯合后吸着的方法,研究了XO螯合形成纤维分离富集微量锆铪的性能。试验研究表明,该纤维能富集浓度低至0.04ppm的锆铪,并且能与大量基体元素相分离;当锆铪总量约为0.41ppm时,采用本方法九次测定的标准偏差为0.21,变异系数为1.05％;回收率可达99.24％。该方法具有操作简便、交换速率快、干扰少、富集能力强、成本低等特点,适用于成分较复杂样品中微量锆铪的分离和富集。     

SDH中STM—1的部分同步复接技术的研究

本文根据CCITT第18研究组1988年6月提出的G·707、G·708和G·709三个建议草案,讨论了同步数字系列(SDH)中的用户负载复接技术,并按有关格式设计实现了4路C—31用户负载的复接器和分接器。