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991.
《Advanced Powder Technology》2022,33(11):103815
Low separation efficiency and large pressure drop are two common problems of cyclones. In this paper, a 3D printed guide vane cyclone separator was designed to study the separation efficiency, turbulent kinetic energy, and particle movement of particle group by experiment and simulation. The results shown that the tangential velocity was the major influence of separating. The bottom of the exhaust pipe was the main region of gas–solid separation and pressure drop. The separation efficiency and pressure drop were positively correlated with the inlet velocity and the particle radius of the fluid. The distribution of turbulent kinetic energy that leaded to the pressure drop loss was concentrated on the inlet of the exhaust pipe. The swirl has external and internal two directions. The optimized cyclone has a longer and narrower blade flow path to obtain higher separation efficiency, especially at low inlet velocity. 相似文献
992.
壳聚糖三甲基季铵盐的合成及其结构表征 总被引:1,自引:0,他引:1
利用壳聚糖分子中氨基的特性,与过量碘甲烷进行彻底甲基化反应合成水溶性的壳聚糖三甲基季铵盐,纯化后进行了结构表征。 相似文献
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利用二次成型工艺制备了PVDF/EG叠层定向结构复合导热材料,并采用X衍射、扫描电镜对PVDF/EG复合材料及形貌进行表征,同时,研究了PVDF/EG叠层定向结构复合导热材料不同方向的热扩散特性、热导特性及材料的机械力学特性.叠层定向结构沿内部薄膜面内方向热扩散系数是其竖直方向的4.1倍,在EG质量分数为15wt%,20 wt%and 25%25wt%时,叠层定向结构PVDF/EG复合材料热导率分别为1.595 W/(m·K)、2.87 W/(m·K)和3.9843 W/(m·K),具有较低的"渗漏"阈值,表明利用二次成型工艺对PVDF/EG复合材料定向结构调控,能达到提高复合材料热导率的目的.而且,PVDF/EG叠层结构复合导热材料具有较好柔韧性,适合作为界面热导材料. 相似文献
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基于流水路由的MAC协议PRMAC(Pipelined Routing Medium Access Control)是无线传感网络WSNs(Wireless Sensor Networks)的典型的基于跨层竞争的同步MAC协议. PRMAC协议允许一个周期内进行多跳传输.但是,PRMAC协议的传输请求发送包RTSD(Request-To-Send Data)和确认发送数据包CTSD(Confirmation-To-Send Data)在同一个数据包窗口传输,降低了路由性能.为此,对 PRMAC 协议进行改进,提出面向多跳场景的 PRMAC 协议 MH-PRMAC(Multi-Hop PRMAC). MH-PRMAC协议采用新的周期结构,并在休眠窗口内设置两个独立窗口,再由它们分别传输RTSD和CTSD包.实验数据表明,提出的MH-PRMAC协议有效地降低了数据包传输时延,并提高了数据包传输率. 相似文献
997.
The current study uses a recently-developed metaheuristic method called Crystal Structure Algorithm (CryStAl) to achieve optimized vibration control in structural engineering. More specifically, this algorithm, which is inspired by the well-established crystallographic principles underlying the formation of crystalline solids in nature, is applied to the optimization of fuzzy logic controllers in building structures. To demonstrate the capability of this method in solving real engineering problems, two real-size building structures, one with three and the other with twenty stories, are considered. The fuzzy controllers are implemented through an active control system to control the seismically-induced vibrations of the structures intelligently. The evaluation criteria utilized to assess the overall performance of the optimization method applied to the fuzzy control system are presented and discussed. Through nonlinear structural analyses, the ductility, energy dissipation, and other nonlinear characteristics of the structures are also considered as the structural responses to be controlled. The computational results obtained from this novel metaheuristic algorithm are compared with those of the other expert systems from the optimization literature. The findings of this paper demonstrate that the Crystal Structure Algorithm is capable of outranking the other methods in the majority of considered cases. 相似文献
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In real-world steganalysis applications, the traditional steganalysis methods built by a set of training data coming from a source may be applied to detect data from another new different source. In this case, the steganalyzers will face a serious problem that training data and test data are no longer subjected to the same distribution, and thus the detection performance would degrade rapidly. To address this problem, a novel transfer subspace learning method with structure preservation for image steganalysis is proposed in this paper. It aims to alleviate the mismatch between the training and test data so as to improve the detection performance. Specifically, a discriminant projection matrix is learned for the training and test data such that the projected data of both sets lie in a common subspace where each sample can be linearly reconstructed by a combination of the training data. In this way, the difference between the training and test sets is decreased. Further, in order to preserve the structure information of features in the projection subspace, a Frobenius-norm based regularization term is introduced into the objective function. Moreover, to mitigate the negative impacts of noises and outliers, a structurally sparse error matrix is introduced to model the noise and outlier information. The formulation of the proposed method can be efficiently solved by an alternating optimization algorithm. The extensive experiments compared with prior arts show the validity of the proposed method for JPEG image mismatched steganalysis. 相似文献
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Zishan Sun Zhenpeng Zhu Ziying Guo Zhan-chao Wu Zichao Yang Tingting Zhang Xinguo Zhang 《Ceramics International》2019,45(6):7143-7150
A high-efficient blue-emitting phosphor Ba3Lu2B6O15: Ce3+ was synthesized by three-step solid-state method. XRD Rietveld refinement analysis reveals that Ba3Lu2B6O15 is of cubic Ia system, owning a high-symmetric layer structure with two regular LuO6 octahedrons and one BaO9 polyhedron. Density functional theory (DFT) calculation result indicates BLB is a kind of direct band-gap material with broad band-gap of ~5.10?eV. Ba3Lu2B6O15:Ce3+ phosphor exhibits a bright blue emission under UV excitation with high quantum efficiency of >?90%, and the possible reasons are discussed basing on structural and spectral data. Because of its excellent luminescent properties, Ba3Lu2B6O15:Ce3+ could be a promising candidate as a blue phosphor for NUV LED devices. 相似文献