纳米SiO_2改性苯丙复合涂料制备及性能研究

通过偶联接枝技术,用硅烷偶联剂对纳米SiO2胶体和苯乙烯丙烯酸乳液进行了有机无机复合,制备了纳米SiO2改性苯丙复合乳液。采用正交试验法研究了复合乳液、填料和添加剂最优配比,分析了它们影响作用。通过试验考察了复合涂料的耐擦洗、附着力、老化和耐沾污等主要性能。结果表明:通过正交试验优选出的最佳涂料配方为14号配方,具体添加量:A为32%、B为2.5%、C为7.8%、D为7.8%、E为13%、F为3.9%、G为0.78%;复合涂料的附着力可达100%,耐洗刷次数可达22 576次,遮盖力为351.675 g/m2,耐沾污性可达95.8%。     

Stimuli-induced core-corona inversion of micelles of water-soluble poly(sodium 2-(acrylamido)-2-methyl propanesulfonate-b-N-isopropylacrylamide)

Micelles of poly(sodium 2-(acrylamido)-2-methylpropanesulfonate-b-N-isopropylacrylamide) (PAMPS-b-PNIPAM) have been investigated in aqueous solutions using various techniques including dynamic light scattering, scanning electron microscopy, transmission electron microscopy and ζ-potential measurements. It was found that PAMPS-b-PNIPAM produces two distinct types of micelle structures; one is a PAMPS-core/PNIPAM-corona structure and the other is a PNIPAM-core/PAMPS-corona structure. The PAMPS-core micelle with the PNIPAM-corona was obtained by insolubilizing the PAMPS block with ferric ion (Fe³⁺) at room temperature, and the PNIPAM-core micelle with the PAMPS-corona was obtained by increasing the solution temperature above the lower critical solution temperature (LCST) of the PNIPAM block in the absence of the Fe³⁺ ion. We have also found that the inversion from one type to the other is reversible. The transformation from the PAMPS-core micelle to the PNIPAM-core micelle was induced by removing Fe³⁺ ion using ethylenediaminetetraacetic acid followed by elevating the temperature above the LCST of the PNIPAM block, while the reverse transformation was triggered by adding Fe³⁺ ion at a lower temperature.     

Reducing the memory of compression Feedforward driving for a new LCD controller

Abstract— The authors have studied a method of reducing the frame memory for signal processing used to improve the response time of liquid crystals. Compared with cases in which quantization is used, the compression Feedforward driving method, which reduces frame memory by applying an image‐compression technique, can effectively reduce the frame‐memory size. The study revealed that errors decrease by 6–10 dB or so if the image data was reduced to 1/3 by means of image compression. Based on the results of the study, the authors have developed a second‐generation LCD controller. With just one SDRAM unit, this LCD controller can produce almost ideal processing effects.     

Evaluation of stress corrosion cracking as a function of its resistance to eddy currents

This study discusses the equivalent conductivity, the equivalent width, and the equivalent resistance of stress corrosion cracks from the viewpoint of eddy current testing. Four artificial stress corrosion cracks were prepared for this study, and their eddy current signals were gathered using two absolute pancake probes and two differential type plus point probes. Then their numerical models were evaluated using finite element simulations on the basis of the measured eddy current signals and their profiles revealed by destructive tests. The results of this study revealed that whereas the equivalent conductivity and the equivalent width depend on the exciting frequency utilized, the equivalent resistance of a crack has much less dependency, which agrees well with an earlier report. This study also revealed that the resistance of a crack depends on probe utilized. Larger probes tend to lead to smaller crack resistance. Pancake type probes tend to lead to larger crack resistance than plus point probes. Analyzing the results together with earlier reports indicates that cracks with a large equivalent conductivity tend to have large equivalent width, and supports the validity of assuming the minimum resistance of a stress corrosion crack whereas considering the conductivity and the width individually would not be viable.     

Utilization of two-directional AC current distribution for enhancing sizing ability of electromagnetic nondestructive testing methods

This paper proposes a novel method for accurately evaluating the depth of a defect using electromagnetic phenomena. The novel method induces AC currents inside a conductive medium and detects the disturbance of the currents. Whereas the principle itself has been utilized in conventional methods, the uniqueness of this new method lies in realizing a current distribution in which there is a region where currents near the surface and those deeply inside the specimen flow opposite to each other. The novel method provides a clear indication corresponding to the depth of the inspected defect. In addition, it enables one to evaluate the depth of a defect that is much deeper than the depth of penetration. After the physical background of this new method is explained, the results of experimental verifications and subsequent numerical simulations are presented.     

Motion adaptive CODEC Feedforward Driving for LCD overdrive

Abstract— The authors have been developing a Feedforward Driving scheme as an overdrive technique to improve LCD response time. Focusing on the reduction of frame memory in overdrive in particular, they are now studying a memory‐reduction method by applying an image‐compression technique. An LSI has already been developed that incorporates a Compression Feedforward Driving unit, which successfully reduced image data to 1/3 by means of the image‐compression technique. This paper reports a study of Motion Adaptive CODEC Feedforward Driving in which a motion adaptation process is added to the CODEC section of the Compression Feedforward Driving unit. This motion adaptation process reduces the amount of errors in overdrive that are caused by memory reduction by using a circuit of the same scale as that for Compression Feedforward Driving.     

Generation of high photocurrent in three-dimensional silicon quantum dot superlattice fabricated by combining bio-template and neutral beam etching for quantum dot solar cells

We fabricated a three-dimensional (3D) stacked Si nanodisk (Si-ND) array with a high aspect ratio and uniform size by using our advanced top-down technology consisting of bio-template and neutral beam etching processes. We found from conductive atomic microscope measurements that conductivity became higher as the arrangement was changed from a single Si-ND to two-dimensional (2D) and 3D arrays with the same matrix of SiC, i.e., the coupling of wave functions was changed. Moreover, our theoretical calculations suggested that the formation of minibands enhanced tunneling current, which well supported our experimental results. Further analysis indicated that four or more Si-NDs basically maximized the advantage of minibands in our structure. However, it appeared that differences in miniband widths between 2D and 3D Si-ND arrays did not affect the enhancement of the optical absorption coefficient. Hence, high photocurrent could be observed in our Si-ND array with high photoabsorption and carrier conductivity due to the formation of 3D minibands.