Post-spinning modification of electrospun nanofiber nanocomposite from Bombyx mori silk and carbon nanotubes

Electrospinning is an effective procedure for fabricating submicron to nanoscale fibers from synthetic polymer as well as natural proteins. We successfully electrospun regenerated silk protein from cocoons of Bombyx mori to produce random as well as aligned fibers with diameter less than 100 nm. The fibers were characterized using field emission environmental scanning electron microscope (ESEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy and wide angle X-ray diffraction (WAXD) studies. Post-spinning treatment with methanol and/or stretching and co-electrospinning with single walled carbon nanotubes (CNT) were carried out to alter the strength, toughness, crystallinity and conductivity of silk nanofibers. Addition of just 1% CNT along with post-spinning treatments resulted in 7-fold increase in the strength and 35-fold increase in the modulus of silk nanofibers. Raman spectroscopy confirmed that CNTs were incorporated in the silk fibers. FT-IR spectroscopy and WAXD studies proved that silk-CNT nanofibers had more crystallinity compared to silk nanofibers without CNT. Four-probe method demonstrated that silk-CNT nanofibers had 4 times higher electrical conductivity compared to silk nanofibers without CNT.     

钻石的零售市场及品牌的重要性

从4C到商业化 几个世纪以来,钻石的买主和拥有者对钻石看重的是其严格按4C评估的瑰丽程度,它们给佩戴者带来的快感,从佩戴者周围激发的敬畏和艳羡.这一情况在20年前达到了顶峰,当时出现于钻石热,报上连篇累牍地报导800美元的黄金和"钻石投资":一克拉D色级无瑕钻石售62000美元,空谈家称,这个价格既使再高一倍仍然便宜,投资热并未持续太久,但其遗产--一种越来越依赖于实验室分级报告和价格表的形式,永远地改变了钻石市场.出版商Martin Rapaport起步于1978年,当时他们报价单的印刷跟不上钻石价格上涨的速度.在供应方面,钻石产量在1980年代翻了一番多;在当时,多亏日本及最后扩展到亚洲其他地区的经济热,全球需求增长了3倍.     

Maximum likelihood time delay estimation in non-Gaussian noise

In a non-Gaussian noise environment, it is theoretically possible to design a delay estimator that performs significantly better than the conventional linear correlator. We study the maximum likelihood estimator for passive time delay in non-Gaussian noise. We show that the form of the best estimator depends strongly on signal-to-noise ratio (SNR), and the estimator optimal at low SNR can fail catastrophically at high values of SNR. The paper uses simulations to examine this sensitivity problem and proposes an ad hoc instrumentation that is reasonably robust over a wide range of SNR values     

Set for determining the dynamic response of electrometric instruments

Translated from Izmeritel'naya Tekhnika, No. 10, pp. 40–41, October, 1988.     

Characterization of monolithic n-type 6H-SiC piezoresistive sensingelements

Monolithic, junction isolated piezoresistors have been fabricated in commercially available 6H-SiC. The gauge factor (GF) of these elements has been measured up to 250°C in both longitudinal and transverse configurations. The maximum GF observed was -29.3, corresponding to the piezoresistive coefficient π₁₁. A beam transducer with a four-arm integral piezoresistor network was fabricated and tested in a force sensor configuration. The data indicate that, n-type 6H-SiC has the potential to be useful in high temperature electromechanical sensors to measure parameters such as pressure, force, strain and acceleration     

The Shadow Meets the Mask: Pyramid-Based Shadow Removal

In this paper we propose a novel method for detecting and removing shadows from a single image thereby obtaining a high‐quality shadow‐free image. With minimal user assistance, we first identify shadowed and lit areas on the same surface in the scene using an illumination‐invariant distance measure. These areas are used to estimate the parameters of an affine shadow formation model. A novel pyramid‐based restoration process is then applied to produce a shadow‐free image, while avoiding loss of texture contrast and introduction of noise. Unlike previous approaches, we account for varying shadow intensity inside the shadowed region by processing it from the interior towards the boundaries. Finally, to ensure a seamless transition between the original and the recovered regions we apply image inpainting along a thin border. We demonstrate that our approach produces results that are in most cases superior in quality to those of previous shadow removal methods. We also show that it is possible to easily composite the extracted shadow onto a new background or modify its size and direction in the original image.