APPLICATION OF CDF（2,2） TO ANALYSIS OF SUSPENDED SEDIMENT IMAGE

The characteristics of suspended sediment image can be reflected by the coefficients of biorthogonal wavelet transform of CDF（2,2）. Based on the power distribution in different scales, an adaptive algorithm is proposed in this paper, whereby the coefficients are adjusted non-linearly. The particle information can be well retained while the useless background is removed. In this way, satisfactory binary image can be obtained for further analysis of the sediment particle.     

Integrated silicon-based suspended racetrack micro-resonator for biological solution sensing with high-order mode

A biological sensing structure with a high-order mode ($\mathrm{E}_{21}^{y}$) is designed, which is composed of a suspended racetrack micro-resonator (SRTMR) and a microfluidic channel. The mode characteristics, coupling properties, and sensing performances are simulated by using the finite element method (FEM). To analyze the mode confinement property, the confinement factors in the core and cladding of the suspended waveguide for the $\mathrm{E}_{11}^{x}$, $\mathrm{E}_{11}^{y}$, and $\mathrm{E}_{21}^{y}$ are calculated. The simulation results show that the refractive index (RI) sensitivity of the proposed sensing structure can be improved by using the high-order mode ($\mathrm{E}_{21}^{y}$). The RI sensitivity for the $\mathrm{E}_{21}^{y}$ mode is ～ 201 nm/RIU, which is twice to thrice higher than those for the $\mathrm{E}_{11}^{x}$ mode and the $\mathrm{E}_{11}^{y}$ mode. Considering a commercial spectrometer, the proposed sensing structure based on the SRTMR achieves a limit of detection (LOD) of ～ 4.7×10^-6 RIU. Combined with the microfluidic channel, the SRTMR can possess wide applications in the clinical diagnostic assays and biochemical detections.     

基于生物光学算法的海洋悬浮粒子检测技术研究

 通过研究分析海水中几种主要物质的固有光学特性,提出了基于生物光学算法的机载蓝绿激光雷达检测海洋悬浮粒子的方法。针对海洋悬浮粒子的两类代表物质浮游植物和非色素悬浮粒子,采用生物光学算法,分别构建了基于机载蓝绿激光雷达的浮游植物叶绿素浓度检测模型和非色素悬浮粒子浓度的检测模型。仿真计算可以证明这两个检测模型能有效探测出浮游植物叶绿素浓度的大小和非色素悬浮粒子浓度,为实际海洋悬浮粒子的检测提供理论基础和技术支持。     

Synthesis of high oil‐absorption resins of poly(methyl methacrylate‐butyl methacrylate) by suspended emulsion polymerization

The synthesis of high oil‐absorption resins by suspended emulsion polymerization process for the first time with butyl methacrylate (BMA) and short‐chain methyl methacrylate (MMA) as the monomers was studied. And the effects of different polymerization technological parameters, such as the comonomer, initiator, crosslinker, emulsifier, dispersant agent, and the agitation rate, on the oil absorbency of high oil‐absorption resins were discussed in detail. The optimum polymerization conditions were obtained. With the increasing contents of these factors, the oil absorbency increased first, and then decreased. The highest oil absorbency to toluene was 17.6 g/g. The particle morphology of the high oil‐absorption resins was observed by scanning electron microscopy (SEM). The resins were determined by FTIR spectrometry. Compared with the high oil‐absorption resins prepared by suspension polymerization process and emulsion polymerization process, the high oil‐absorption resins prepared by suspended emulsion polymerization process had the higher oil absorbency, faster oil‐adsorbing rate, better oil‐retention, and regeneration property. Copyright © 2010 John Wiley & Sons, Ltd.     

磁悬浮飞轮锁紧装置发射段微动行为研究

采用正弦扫频振动和随机振动模拟卫星发射振动工况,对磁悬浮飞轮锁紧装置在不同锁紧力下的微动行为进行研究,并利用电涡流位移传感器测量定、转子在锁紧接触面处的微动位移,发现锁紧面处存在包含切向和径向的复合微动.实验后,采用扫描电子显微镜对3种锁紧接触副(1 Cr18Ni9Ti/GCr15,渗氮1Cr18Ni9Ti/GCr15和GCr15/GCr15)的锁紧表面进行分析.结果表明:锁紧力从200 N增至300 N时,最大微动位移从60 μm降至8μm,相应的微动位移最大振幅从25μm降至4μm,使得切向微动从滑移区变化至部分滑移区,从而降低了切向微动磨损程度.而增加接触刚度或选择相似接触体可减小微滑发生机率,避免径向微动损伤.两者共同作用,抑制了锁紧面内的复合微动损伤发生.     

甲基红掺杂碳纳米管悬浮液的光限幅特性研究

利用实验的方法研究了甲基红掺杂碳纳米管悬浮液对波长为532 nm激光的光限幅效应.分析了样品厚度和入射激光重复频率对光限幅特性的影响,并与纯碳纳米管悬浮液的光限幅特性进行了比较.实验结果表明,对于线性透过率为60%（500 nm）的碳纳米管悬浮液,掺入甲基红后其沉淀速度明显减慢,限幅阈值由250 μJ降低为200 μJ;对于2和5 mm 厚度的样品,掺杂甲基红使碳纳米管悬浮液的箝位输出激光脉冲能量分别由45和20 μJ降低为35和9 μJ. 关键词： 非线性光学 光限幅效应 甲基红 染料掺杂碳纳米管悬浮液     

A Versatile Metalloporphyrinic Framework Platform for Highly Efficient Bioinspired,Photo‐ and Asymmetric Catalysis

Even though numerous bioinspired catalysts have been developed, there remain huge gaps between the artificial and natural catalysts, because it is very difficult to imitate simultaneously the complicated constituents, structures, and synergistic effect of enzymes. We report herein a versatile metalloporphyrinic framework platform, which exhibits high efficiency in bioinspired catalysis, photocatalysis, and asymmetric catalysis. The catalytic properties are highly dependent on the tunable constituents and their cooperation, and are significantly superior to the corresponding molecular catalyst systems which lack the synergistic effects. Since there are numerous functional moieties that can readily be incorporated into the metalloporphyrinic framework platform, a myriad of applications can be simply realized by embedding different functional moieties.     

基于MSCMG大型遥感卫星高精度姿态控制方法

针对大力矩飞轮前馈和闭环反馈补偿复杂、对精度影响敏感性大的问题,提出了基于磁浮控制力矩陀螺闭环补偿的大型遥感卫星高精度姿态控制方法。该方法采用磁悬浮力矩陀螺为控制执行机构,通过变结构反馈补偿控制律设计,建立新的运动补偿控制系统,减小相机和卫星本体耦合效应。基于磁浮力矩陀螺力矩大、反向激励扰动小、精度高的特性,将其应用于对地遥感成像相机运动补偿控制系统中,仿真结果表明,与飞轮前馈补偿相比,姿态稳定度提高了一个数量级,有效提高空间大惯量卫星姿态控制的稳定度,提升相机对地成像质量;研究结果可为甚高精度卫星姿态控制与载荷运动补偿提供参考。     

基于初弯曲单元的某弦支穹顶非线性稳定承载力分析

在单元的随动坐标系下,建立了初始弯曲对杆单元轴向刚度影响的计算公式,导出了考虑初始弯曲的非线性杆单元刚度矩阵;从经典的梁-柱理论出发,给出了考虑初始弯曲的非线性空间梁单元切线刚度矩阵推导过程。将建立的初始弯曲单元应用于弦支穹顶结构算例的非线性稳定承载力分析,研究了杆件初始弯曲对结构整体非线性稳定性能的影响,结果表明,杆件初始弯曲的存在会降低结构的整体刚度和极限承载力,而在不同的初始预应力状态下,极限荷载随初始弯曲增加都基本呈线性下降,并且其关系曲线基本平行。本文建立的基于初弯曲单元的非线性分析方法,可推广应用于各种类型空间网格结构的非线性分析,为结构设计方案的选择提供更为科学的依据。     

Electrodeposited nickel-cobalt composite coating containing MoS2

Ni-Co/MoS₂ composite coatings were prepared by electrodeposition in a Ni-Co plating bath containing nano-sized MoS₂ particles to be co-deposited. The polarization behavior of the composite plating bath was examined on a PAR-273A potentiostat/galvanostat device. The friction and wear behaviors of the Ni-Co/MoS₂ composite coatings were evaluated with UMT-2MT test rig in a ball-on-disk contact mode. The morphologies of the original and worn surfaces of the composite coatings were observed on scanning electron microscope (SEM). It was found that the introduction of MoS₂ nano-particulates in the electrolyte caused the shift towards larger negatives of the reduction potential of the Ni-Co alloy coating, and the co-deposited MoS₂ showed no significant effect on the electrodeposition process of the Ni-Co alloy coating. However, the co-deposited MoS₂ led to changes in the surface morphology and structure of the composite coating as well. Namely, the peak width of the Ni-Co solid solution for the composite coating is broader as compared to that of the Ni-Co alloy coating. The co-deposited MoS₂ particulates were uniformly distributed in the Ni-Co matrix and contributed to increase tribological properties of the Ni-Co alloy coating.