环氧树脂水基化化学改性的研究

用对氨基苯甲酸改性环氧树脂 ,使其成为具有亲水性的树脂。测定了改性树脂的溶解性 ,发现改性后树脂在有机溶剂中的溶解性能变差 ,但在碱性溶剂中溶解性增强。对改性树脂进行了红外光谱表征 ,并根据环氧基特征峰的吸收对环氧基转化率进行了定量分析。测定了改性产物的DSC曲线 ,发现随着反应物中对氨基苯甲酸比例的提高 ,改性产物的玻璃化转变温度升高。涂膜的性能测试表明 ,对氨基苯甲酸改性环氧树脂水基涂料的机械力学性能和耐化学试剂性能比溶剂型纯环氧树脂要优越。     

1.32 μm Nd3+∶YAG Pulse Laser

Using specially coated mirrors, an output energy of 0.97 J at 1.32 μm from a Nd3+∶YAG pulse laser is obtained with pumping energy of 66 J. The repetition rate is 1 pulse/sec and the slope efficiency is 1.7%. The repetition rate can be changed from 1 pulse/sec to 10 pulses/sec.     

c-di-GMP displays a monovalent metal ion-dependent polymorphism

Cyclic diguanosine monophosphate (c-di-GMP) is known to be an important signaling molecule that regulates the formation of bacterial biofilms. We demonstrate here by UV, CD, and NMR that it displays a surprising polymorphism that varies with the monovalent counterion and is consistent with the formation of a G-quartet structure in K+ and a stacked structure in Li+ or Na+. The ability of this rigid molecule to adopt different alignments may be important to its biological role.     

微流体驱动与控制技术研究进展

随着微流体系统,尤其是生物芯片和缩微芯片实验室(lab-on-a-chip)技术的发展,微米乃至纳米尺度构件中流体的驱动与控制技术越来越引起人们的注意.由于微流体流动的影响因素众多,它的驱动和控制技术,与宏观流体相比,更为复杂和多样化.本文首先结合流体的驱动和控制技术,并着眼于微观与宏观的不同,对微流体的流动特性进行了分析,然后对目前微流体驱动与控制技术的研究进展进行了总结,对各种微流体的驱动和控制技术进行了对比,并对他们各自的优缺点进行了分析和讨论.      

(NaZSM-5)-AgI主体-客体纳米复合材料的研究

Silver iodide nanoclusters were successfully prepared in the channels of NaZSM-5 zeolite by a thermal diffusion method. Chemical analysis, powder X-ray diffraction, nitrogen adsorption technique, and infrared spectroscopy were used to characterize the prepared samples. The solid diffuse reflectance absorption spectra and luminescence properties were studied. Chemical analysis showed that the guest silver iodide was incorporated into the host NaZSM-5. Powder X-ray diffraction analysis showed that the framework of NaZSM-5 still remained in the (NaZSM-5)-AgI samples. Infrared spectra indicate that the vibration of the framework of NaZSM-5 had little variation attributable to the encapsulation of AgI in the host. This phenomenon is due to the incorporation of silver iodide into NaZSM-5. Investigation of the absorption revealed that the guest silver iodide was encapsulated in the channels of NaZSM-5. Solid diffuse reflectance absorption spectra indicated that the absorption of prepared (NaZSM--5)-AgI host-gust samples had nothing with the host NaZSM-5. The absorption spectra of the (NaZSM-5)-AgI samples were influenced by the size of AgI nanoclusters. Luminescence investigation showed that the prepared samples had a high energy band gap and a strong radiation process. The (NaZSM-5)-AgI samples are luminescient composite materials.     

Analysis and demonstration of PID algorithm based on arranging the transient process for adaptive optics

The fastness and robustness of a control algorithm are highly important in the performance of adaptive optics systems. The proportional-integral-derivative control with arranging the transient process, which is designed using a tracking differentiator, is applied into an adaptive optics system. This control algorithm greatly improves the dynamic properties of the control system. To identify the underlying reasons for these improvements, the influence of the control algorithm is theoretically discussed. The control algorithm is verified by a simple adaptive optics system for tip/tilt correction. The experimental results demonstrate that the control algorithm is fast and robust.     

Effect of nonrigid registration algorithms on deformation-based morphometry: a comparative study with control and Williams syndrome subjects

Deformation-based morphometry (DBM) is a widely used method for characterizing anatomical differences across groups. DBM is based on the analysis of the deformation fields generated by nonrigid registration algorithms, which warp the individual volumes to a DBM atlas. Although several studies have compared nonrigid registration algorithms for segmentation tasks, few studies have compared the effect of the registration algorithms on group differences that may be uncovered through DBM. In this study, we compared group atlas creation and DBM results obtained with five well-established nonrigid registration algorithms using 13 subjects with Williams syndrome and 13 normal control subjects. The five nonrigid registration algorithms include the following: (1) the adaptive bases algorithm, (2) the image registration toolkit, (3) The FSL nonlinear image registration tool, (4) the automatic registration tool, and (5) the normalization algorithm available in Statistical Parametric Mapping (SPM8). Results indicate that the choice of algorithm has little effect on the creation of group atlases. However, regions of differences between groups detected with DBM vary from algorithm to algorithm both qualitatively and quantitatively. Some regions are detected by several algorithms, but their extent varies. Others are detected only by a subset of the algorithms. Based on these results, we recommend using more than one algorithm when performing DBM studies.     

Analysis of top-hat selection transformation and some modified top-hat transformations

This paper analyzes the relationships between top-hat selection transformation and some modified top-hat transformations. Firstly, several top-hat transformations following different applications are reviewed. Then, the relationship between top-hat selection transformation and each other top-hat transformation is analyzed and proofed. Finally, we show that some other top-hat transformations may be derived from top-hat selection transformation. Moreover, different parameter specifications of top-hat selection transformation result in different types of top-hat transformations, which may generate efficient top-hat transformations for different application purposes. Therefore, top-hat selection transformation is useful for the research and application of top-hat transformation.