Smart carboxymethylchitosan hydrogels that have thermo‐ and pH‐responsive properties

Thermo‐responsive poly(N‐isopropylacrylamide) (poly(NIPAAm)) and pH‐responsive poly(N,N′‐diethylaminoethyl methacrylate) (poly(DEAEMA)) polymers were grafted to carboxymethylchitosan (CMC) via radical polymerization to form highly water swellable hydrogels with dual responsive properties. Ratios of CMC, NIPAAm to DEAEMA used in the reactions were finely adjusted such that the thermo and pH responsiveness of the hydrogels was retained. Scanning electron microscopy (SEM) indicated the formation of an internal porous structure for the swollen CMC hydrogels upon incorporation of poly(NIPAAm) and poly(DEAEMA). Effect of temperature and pH changes on water swelling properties of the hydrogels was investigated. It was found that the water swelling of the hydrogels was enhanced when the solution pH was under basic conditions (pH 11) or the temperature was below its lower critical solution temperature (LCST). These responsive properties can be used to regulate releasing rate of an entrapped drug from the hydrogels, a model drug, indomethacin was used to demonstrate the release. These smart and nontoxic CMC‐based hydrogels show great potential for use in controlled drug release applications with controllable on‐off switch properties. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41505.     

Monitoring Highly Correlated Multivariate Processes Using Hotelling's T2 Statistic: Problems and Possible Solutions

Hotelling's T² statistic is the default control statistic for continuous multivariate data, but there are dangers in applying this statistic without the appropriate level of checks and balances. This paper discusses the potential issues with using the Hotelling's T² statistic when the quality variable measures are highly correlated and provides some solutions that will help mitigate the risks with applying the Hotelling's T² control charts in such practical examples. Copyright © 2014 John Wiley & Sons, Ltd.     

脉冲功率电容器用PbLa(ZrTi)O_3陶瓷性能研究

采用固相反应法制备了Pb0.96La0.06(Zr1-xTix)O3陶瓷,研究了Ti含量对所制陶瓷的电性能和储能特性的影响。结果表明,PbLa(ZrTi)O3陶瓷介电常数与电场强度呈非线性变化关系。当Ti含量x为0.08时,所测电滞回线细长狭窄,并呈下凹趋势,此时极化强度为22.18×10–6 C/cm2,储能密度为1.06 J/cm3。通过流延法制备的脉冲功率电容器击穿电压可大幅度提升,储能密度达1.95 J/cm3,具有高能量转换效率。     

一种多维网格编码译码器的高效FPGA设计

为在实时通信系统中有效利用多维网格编码调制(MDTCM)的短码特性,设计了一种适合FPGA实现的高效多维网格编码译码器。在该设计中,提出了一种易于硬件实现的改进归一化译码算法,采用四级流水线和乒乓环结构,并充分利用译码算法中的固有特性,有效降低了资源消耗和译码延迟。测试表明,该设计简单可靠,性能稳定,易于移植扩展,非常适合实时通信场合的应用,目前该译码器已成功应用于某实时通信系统中。     

多尺度变换和粒子群优化的图像融合方法

在图像融合领域,基于多尺度变换的图像融合方法是研究的热点,文中提出了一种基于多尺度变换和粒子群优化的图像融合方法,对基于多尺度变换得到的融合图像,利用粒子群优化进行进一步处理,并讨论了优化算法中初始图像质量对最终结果的影响。实验结果表明,该算法具有较好的融合结果,且优化时选取偏差大的初始图像粒子,能够获得更好的融合结果。     

基于电喷雾质谱的反应监测研究进展

电喷雾质谱(ESI-MS)因具有灵敏度高、响应速度快、分辨率高、原位在线监测等特点,广泛应用于反应监测领域。本文主要从不同离子化技术角度,综述了电喷雾质谱在反应监测和机理研究方面的进展。重点介绍了在线电喷雾质谱技术,其中包括解吸附电喷雾离子化质谱（DESI-MS）、萃取电喷雾离子化质谱（EESI-MS）、纳升电喷雾离子化质谱（nESI-MS）、超声喷雾离子化质谱（SSI-MS）以及其他在线电喷雾离子化质谱在反应监测中的应用。最后,对电喷雾质谱在反应监测的发展趋势进行总结和展望。     

What matters the most for economic development? Evidence from the Community Development Financial Institutions Fund

Governments use incentive programmes to attract new businesses. Due to limited resources, there are questions about which incentives are most effective. Using establishment data from California, and data on the location of disbursements through two federal programmes, we consider the effectiveness of different programmes in attracting new businesses. We find that the amount of funding through the New Markets Tax Credit programme has a significant impact on business activity but find no evidence of an effect from the Community Development Financial Institutions programme. Our results suggest that the effectiveness of these programmes depends on how they provide assistance.     

Dwell-Fatigue of Ni-Based Superalloys with Serrated and Planar Grain Boundary Morphologies: The Role of the γ′ Phase on Strain Accumulation and Cavitation

The effect of grain boundary (GB) morphology on the cavitation behavior in a Ni-based superalloy, RR1000, was studied during elevated temperature dwell-fatigue at 700 °C. Following a solution heat treatment, the material was control cooled at two different rates, resulting in high angle GB morphologies that were tailored as either serrated or planar. The resulting γ′ precipitate structures were characterized near GBs and within grains. Along serrated GBs coarsened and elongated γ′ precipitates formed and consequently created adjacent regions that were denuded of γ′ precipitates. Cyclic dwell-fatigue experiments were performed at low and high stress amplitudes to vary the amount of imparted strain on the specimens. A combination of electron backscatter diffraction and digital image correlation were used to resolve strain localization relative to the GBs, in which strain accumulation was found to precede cavity formation. Additionally, the regions denuded of the γ′ precipitates were observed to localize strain and to be initial sites of cavitation. These results present a quantitative strain analysis between two variants of an RR1000 alloy, which provides the micromechanical rationale to assess the increased proclivity for serrated GBs to form cavities.