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981.
982.
983.
基于随机共振的电子鼻系统构建及在谷物霉变程度检测中的应用 总被引:3,自引:0,他引:3
谷物霉变不但给世界各国带来巨大的经济损失,同时也严重的危害着食用者的健康甚至生命安全.目前我国的谷物霉变检测技术具有一定的滞后性,因此研制一套检测谷物霉变程度的电子鼻系统具有重要价值.开发了一种基于半导体气敏传感器阵列的便携式电子鼻系统,采用非线性双稳态随机共振系统处理霉变谷物检测信号,不但可提取谷物霉变特征信息,同时... 相似文献
984.
Abstract Two types of GaAs/AIGaAs laser arrays, each consisting of five emitters and suitable for high power operations, have been fabricated and tested. They are easily fabricated, have high yield and deliver high power. The first array structure was fabricated using proton implantation to define the active lasing channels. Damage introduced by proton bombardment provides both electrical and optical confinement for the lasing channels. We have investigated the effect of heat treatment on the performance of these lasers and have found that the heat treated samples had a lower threshold current and higher quantum efficiency. For 400 μm long devices, with uncoated facets, we have measured a threshold current of 200 mA and a peak power of 231 mW/facet. The highest external quantum efficiency is 60%. We have also fabricated laser arrays with a simple, self‐aligned, index guided ridge waveguide structures. We have obtain a pulsed output power of up to 551 mW/facet with a quantum efficiency of 37.4%. The typical threshold current is 370 mA. 相似文献
985.
Yong-Cheng Wong Yung-Jin Weng Yung-Chun Weng 《Polymer-Plastics Technology and Engineering》2013,52(8):853-860
This study developed creative imprinting technology, combining nano-imprint lithography and array-type UV-curing technology. It used nanopowders as the method to transmit imprint force, and integrated technical features, such as soft lithography, light-curing resistant and gas-assisted imprint technology, in order to study the development of technological processes of micro-lens array manufacturing, and mature the application and technology of nano-imprinting. According to research results, SUS 304 stainless steel sheet with a micro-hole array could be smoothly fabricated into an original micro-lens array mold upon gas-assisted micro-hot embossing. At the same time, a micro-lens array structure with a complementary external form could be precisely remolded and reproduced by PDMS. Complete molding of micro-lens could be effectively achieved by combining imprints of gas-assisted lithography developed in this study, and even UV-NIL. The effective imprinting area and reproducibility of transfer printing could be greatly improved when a micro-lens contacts perfectly with a substrate surface. Moreover, since PDMS soft molds have short remolding times, and are easily feathered during manufacturing, production costs could be effectively reduced through features such as, low surface free energy, resistant to adhering to the mold during imprinting, and collocation of gas-assisted nanopowder imprinting of micro-structural processes. 相似文献
986.
The bubbling–jetting transition regimes from large orifice submerged in water were investigated for various orifice diameters. A simple and fast way for identifying the regime transition was successfully developed using electrical capacitance tomography (ECT). In all the experiments deionised water was liquid phase and air was gas phase. Orifice gas velocity (VN) and orifice diameter (do) were varied from 0.8 to 186 m/s and 4–21 mm, respectively. It was found that the VN,trans. strongly depends on the orifice diameter. In the small orifice diameter (do < 10 mm), VN,trans. greatly decreases with the increase of orifice diameter. However, in the large orifice diameter (do > 10 mm), the effect of orifice diameter on the transition velocity is insignificant. Finally, the data obtained by ECT compares with other works and the dimensionless orifice Reynolds number (Reo ~11,000) is preferred to identify the bubbling–jetting transition regimes. 相似文献
987.
We give two optimal linear-time algorithms for computing the Longest Previous Factor (LPF) array corresponding to a string w. For any position i in w, LPF[i] gives the length of the longest factor of w starting at position i that occurs previously in w. Several properties and applications of LPF are investigated. They include computing the Lempel-Ziv factorization of a string and detecting all repetitions (runs) in a string in linear time independently of the integer alphabet size. 相似文献
988.
The paper presents a new method to derive data distributions for parallel computers with distributed memory organization by a mathematical optimization technique. Prerequisites for this approach are a parameterized data distribution and a rigorous performance prediction technique that allows us to derive runtime formulas containing the parameters of the data distribution. A mathematical optimization technique can then be used to determine the parameters in such a way that the total runtime is minimized, thus also minimizing the communication overhead and the load imbalance penalty. The method is demonstrated by using it to determine a data distribution for the LU decomposition of a matrix. 相似文献
989.
Vertically aligned Fe arrays have been self-assembled on anodic aluminum oxide templates by evaporation. The rims of the pores, which act as obstacles to the stacking of atoms, prevent them from forming continuous films. By controlling the Fe nominal thicknesses (τn) from 400 to 5 nm, the morphology is changed from continuous film to isolated arrays, leading to the change of the predominant magnetization reversal from domain wall motion to spin rotation. For samples with τn < 59 nm, isolated, rather than interconnected, morphology is formed. In this range, the coercivity shows a spectacular change for τn = 47 nm, with an array diameter of about 52 nm, achieving a maximum of about 38 kA/m. The critical dimension of single-domain array is therefore determined. The magnetostatic and exchange interactions are reduced due to the thermal fluctuation, and the magnetization leaves from the in-plane direction to be randomly distributed in 3-D, for τn < 27 nm. 相似文献
990.
未知噪声背景下基于数据阵共轭重构的MUSIC角估计算法 总被引:1,自引:0,他引:1
详细讨论了在未知噪声背景下,利用接受数据阵及其共轭重构得到新的数据阵,并借助数据阵的奇异值分解实现UMMUSIC算法(未知噪声背景下的修正多信号分类法),这将有助于改善估计的分辨性及改善协方差阵特征值的分布;同时能更有效地应用于实际,并给出了验证理论分析的计算机仿真结果。 相似文献