坝基不同倾角软弱夹层的破坏模式及D-C模型参数研究

坝基岩体中的软弱夹层对抗滑稳定影响重大,因此对其破坏模式及本构模型参数的研究具有重要意义。采用软弱夹层重塑样进行三轴压缩试验,下部未泥化部分采用泥化部分土掺入20%水泥代替,上部采用泥化部分土制样,泥化部分与未泥化部分交界面分别制成0°,30°,45°,60°倾斜面并作粗糙处理模拟实际界面特性。试验结果表明:含不同倾角结构面的软弱夹层试样临界角范围为58.3°～61.7°,当结构面倾角介于临界角范围之内时,软弱夹层试样沿结构面破坏,当结构面倾角位于临界角范围之外时,软弱夹层试样在上部泥化部分土中破坏;对软弱夹层试样三轴试验ε((σ_1-σ_3))–ε_1关系曲线进行线性拟合,结果表明,随围压增加,试样初始切线模量及极限破坏强度均增加,根据试验结果得出了相应的D-C模型参数并将其应用于坝基抗滑设计中,取得了良好效果。本研究成果对坝基软弱夹层的抗滑设计及同类软弱夹层工程性质的研究具有一定参考价值。     

正交异性钢桥面板结构体系的疲劳破坏模式和抗力评估

正交异性钢桥面板的疲劳问题属于包含多疲劳破坏模式的结构体系疲劳问题。基于这一本质特性,以典型的正交异性钢桥面板结构体系为研究对象,由结构体系的主导疲劳破坏模式出发,提出正交异性钢桥面板结构体系疲劳抗力评估的新方法。以纵肋与顶板焊接细节和纵肋与横隔板交叉构造细节为主要研究对象,设计8个足尺节段模型,主要包括传统纵肋与顶板焊接细节、新型镦边纵肋与顶板焊接细节和纵肋与横隔板交叉构造细节,通过模型试验研究了两类重要构造细节的主导疲劳破坏模式和实际疲劳抗力,在此基础上结合切口应力评估方法探讨正交异性钢桥面板构造细节切口应力S-N曲线方程、结构体系的主导疲劳破坏模式等关键问题。研究结果表明：传统纵肋与顶板焊接细节和新型镦边纵肋与顶板焊接细节的主导疲劳破坏模式均为疲劳裂纹萌生于焊根并沿顶板厚度方向扩展,二者的实际疲劳抗力基本相同;纵肋与横隔板交叉构造细节的疲劳破坏模式为焊趾开裂沿纵肋腹板方向扩展;对于研究对象而言,萌生于纵肋与顶板焊接细节焊根并沿顶板厚度方向扩展的疲劳破坏模式为控制结构体系疲劳抗力的主导疲劳破坏模式。     

A ternary mechanism for the facilitated transfer of metal ions onto metal–organic frameworks: implications for the ‘‘versatility’’ of these materials as solid sorbents

Although metal–organic frameworks offer a new platform for developing versatile sorption materials, yet coordinating the functionality, structure and component of these materials remains a great challenge. It depends on a comprehensive knowledge of a “real sorption mechanism”. Herein, a ternary mechanism for U(VI) uptake in metal–organic frameworks was reported. Analogous MIL-100s (Al, Fe, Cr) were prepared and studied for their ability to sequestrate U(VI) from aqueous solutions. As a result, MIL-100(Al) performed the best among the tested materials, and MIL-100(Cr) performed the worst. The nuclear magnetic resonance technique combined with energy-dispersive X-ray spectroscopy and zeta potential measurement reveal that U(VI) uptake in the three metal–organic frameworks involves different mechanisms. Specifically, hydrated uranyl ions form outer-sphere complexes in the surface of MIL-100s (Al, Fe) by exchanging with hydrogen ions of terminal hydroxyl groups (Al-OH₂, Fe-OH₂), and/or, hydrated uranyl ions are bound directly to Al(III) center in MIL-100(Al) through a strong inner-sphere coordination. For MIL-100(Cr), however, the U(VI) uptake is attributed to electrostatic attraction. Besides, the sorption mechanism is also pH and ionic strength dependent. The present study suggests that changing metal center of metal–organic frameworks and sorption conditions alters sorption mechanism, which helps to construct effective metal–organic frameworks-based sorbents for water purification.     

2-(苯甲基)-7-氯茚并[1,2-e][1,3,4]噁二嗪-2,4a(3H,5H)-二羧酸4a甲酯的合成

以5-氯-1-茚酮为起始原料,经羰基化、不对称氧化、腙化和缩合反应合成了高效杀虫剂茚虫威的关键中间体2-(苯甲基)-7-氯茚并[1,2-e][1,3,4]噁二嗪-2,4a(3H,5H)-二羧酸4a甲酯。以5-氯-1-茚酮计,产品总收率达61.1%,产品结构经核磁共振分析验证。探讨了原料配比、溶剂的选择、氧化剂等因素对反应收率的影响。     

磁性胺基化石墨烯多分散固相微萃取光度法测定制霉菌素

合成的磁性胺基化石墨烯用FT-IR进行表征,并将其用于水溶液中制霉菌素的多分散固相微萃取,考察了吸附剂用量、吸附时间、初始浓度以及溶液pH等条件对萃取性能的影响,结合分光光度法建立了定量测定制霉菌素的分析方法。     

基于DSP的智能车辆系统移动小车的设计

通过对当今智能车辆系统的研究,本文以TMS320LF2407A 数字信号处理器为主控芯片构建了一种应用在智能车辆控制系统中的移动小车.利用TMS320LF2407A DSP丰富的集成外设和高速的运算能力,对移动小车控制系统进行了整体设计,并详细描叙了系统的硬件设计和软件设计,并且实现了通过无线通讯来实时控制小车的运行.实验过程中,小车运行平稳,表现出良好的机动性和灵活性.实验结果表明,以DSP为核心的移动小车控制系统,具有优秀的数字处理性能,能够运行一些高级的先进算法来提高控制系统的性能,并且系统的实时性能强,与传统的单片机或微控制器控制系统比起来,更加符合智能交通领域智能车辆控制系统的设计要求.     

3D optical vortices generated by micro-optical elements and its novel applications

In this paper we report on recent development in the areas of optical vortices generated by micro-optical elements and applications of optical vortices, including optical manipulation, radial polarization and secure free space optical communi- cation     

Effect of exit and injection rates on phase-dependent transient evolution of gain without inversion

It is shown that in an open Λ-type system with spontaneously generated coherence, the transient evolution rule of the gain of lasing without inversion (LWI) is very sensitive to variation of the relative phase φ between the probe and driving fields; the variety of the atomic exit rateγ_0 and the ratio C of the atomic injection rates also have a considerable effect on the phase-dependent transient evolution rule of LWI gain. We find that whenφ=0, the transient and stationary LWI gain increases with C increasing but decreases with γ_0 increasing; whenφ≠0 , the effect of C andγ_0 on LWI gain is just opposite to that when φ=0 ; in order to get the largest transient and stationary LWI gain, we need selecting suitable values of φ,γ_0 and C.     

波分系统光层面保护技术的应用研究

本文首先分析了光层面的保护技术,并对目前比较成熟的光线路保护（OLP）、光通道保护（OCP）技术进行了探讨,接着本文从实际工程应用的角度,探讨了光层保护技术的实际应用以及一些需要注意的问题,最后对光层保护的发展方向做了展望。