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31.
Ning Wang Yinya Li Guoqing Qi Andong Sheng 《International Journal of Adaptive Control and Signal Processing》2019,33(7):1174-1188
This paper investigates the state estimation issue for a class of wireless sensor networks (WSNs) with the consideration of limited energy resources. First, a multirate estimation model is established, and then, a new event‐triggered two‐stage information fusion algorithm is developed based on the optimal fusion criterion weighted by matrices. Compared with the existing methods, the presented fusion algorithm can significantly reduce the communication cost in WSNs and save energy resources of sensors efficiently. Furthermore, by presetting a desired containment probability over the interval [0,1] with the developed event‐triggered mechanism, one can obtain a suitable compromise between the communication cost and the estimation accuracy. Finally, a numerical simulation for the WSN tracking system is given to demonstrate the effectiveness of the proposed method. 相似文献
32.
33.
Dai-Yu Zhang Jun-Ru Qi Wen-Xin Jiang Jin-Song Liao Xiao-Quan Yang 《International Journal of Food Science & Technology》2021,56(10):5230-5241
In this study, pectin polysaccharide (SDPP) was obtained from soybean dreg (26.2% yield), and characteristics of SDPP were compared with those of soybean soluble polysaccharides (SSPS) and citrus pectin (HMP). The galacturonic acid and molecular weight of SSPS, SDPP or HMP were 11.8%, 40.6% or 70.2% and 112, 446, or 440 kDa. SDPP had similar viscosity and protein content to SSPS, and functional groups and linear structure to HMP. SSPS, SDPP or HMP differed in particle size of 260, 467 or 1195 nm and ζ–potential of −5.8, −14.6 or −23.5 mV at pH 4.0. The precipitation of acidified milk drink (AMD) was 6.31% without stabiliser or below 1.75% with 0.4% SDPP at pH 3.6–4.6. These results suggested that SDPP combines the structure and characteristic of HMP and SSPS, and AMD with SDPP had great stabilising behaviour at wider pH range (pH 3.6–4.6). 相似文献
34.
Biyun Fang Chuanfeng Zhang Zeliang Qi Chunyan Li Jun Ni Xiuyun Wang Jianxin Lin Chak-Tong Au Bingyu Lin Lilong Jiang 《American Institute of Chemical Engineers》2022,68(11):e17849
The design of an efficient non-noble metal catalyst is of burgeoning interest for ammonia synthesis. Herein, we report a Mo2C/CeO2 catalyst that is superior in ammonia synthesis activity. In this catalyst, molybdenum carbide coexisted with the ceria overlayers which is from the ceria support as the strong metal–support interaction. There is a high proportion of low-valent Mo species, as well as high concentration of Ce3+ and surface oxygen species. The presence of Mo2C and CeO2 overlayers not only leads to enhancement of hydrogen and nitrogen adsorption, but also facilitates the desorption and exchange of adsorbed species with the gaseous reagents. Compared with the Mo/CeO2 catalyst prepared without carbonization, the Mo2C/CeO2 catalyst is more than sevenfold higher in ammonia synthesis rate. This work not only presents an explicit example of designing Mo-based catalyst that is highly efficient for ammonia synthesis by tuning the adsorption and desorption properties of the reactant gases, but opens a perspective for other elements in ammonia synthesis. 相似文献
35.
Effective distribution coefficients of 9 impurities in 1,2-diphenylethane have been calculated by directional crystallization under different ambient frozen temperature. The effect of varied zone size, temperature difference between the melt and ambient frozen environment, number of zone on purity of 1,2-diphenylethane have been also investigated during the process of zone refining. The results indicate that the product purity in the intermediate purified region with varied zone size is higher 0.04%-0.2% than that with constant zone size. The product purity increases with temperature difference between the melt and ambient frozen environment. The appropriate temperature difference is adopted 50℃. The product purity in the intermediate region of sample bar with 2 molten zones is higher 0.05%-0.43% than that with 1 molten zone. In addition, the change of enthalpy and entropy between impurities and 1,2-diphenylethane have been determined. 相似文献
36.
Catalysis Letters - In this paper, five recombinant strains: GS115-LacA, GS115-LacB, GS115-LacC, KM71H-Lcc1 and GS115-Lcc2 were selected to produce laccase isozymes with high activities, which... 相似文献
37.
通过金相试验方法测定42CrMo钢在890~930 ℃下保温10~240 min后的晶粒尺寸。结果表明,42CrMo钢在加热到试验温度890~930 ℃时已经完全奥氏体化,保温过程中的晶粒生长属于正常生长;加热温度对晶粒尺寸的影响较大,保温时间对晶粒尺寸的影响较小;随保温时间的延长晶粒生长缓慢,晶粒尺寸与保温时间满足指数小于1的函数关系。基于试验数据,通过线性回归得到晶粒长大的Beck模型参数,通过非线性回归得到Sellars和Anelli模型参数,3个模型的预测精度都较好,而Anelli模型的适用性要高于Beck模型和Sellars模型,故在预测42CrMo钢的奥氏体晶粒长大规律时宜使用Anelli模型。 相似文献
38.
Ceramic matrix composites (CMC) are highly required in many fields of science and engineering. However, the CMC parts always have poor surface finish. This study attempts to improve cutting performance of CMC material by combing the advantages of ultrasonic assisted cutting and diamond wire sawing. Cutting force, surface roughness, machined edge and tool wear are analyzed based on experimental results. It shows that the oscillatory movement of tool edges provides positive effect on particle ejection and residual material reduction. Ductile chip formation can be achieved due to the small tip radius of grits. Obvious decrease in cutting force, surface roughness and tool wear are obtained. Moreover, burrs, fuzzing and fracture are reduced. Meanwhile, both the surface characteristics and shape accuracy are significantly improved. These results provide a valuable basis for application of ultrasonic assisted wire sawing and understanding of CMC cutting mechanisms. 相似文献
39.
The effect of Li2O on the crystallization properties of CaO-Al2O3-SiO2-Li2O-Ce2O3 slags was investigated. With increasing the Li2O content, LiAlO2 and CaCeAlO4 were the main crystalline phases. LiAlO2 formed for the charge compensating of Li+ ions to [AlO45?]-tetrahedrons, and CaCeAlO4 formed as a result of the charge balance of Ce3+ ions, Ca2+ ions, and [AlO69?]-octahedrons. Increasing the content of Li2O to 10%, the crystallization temperature was the highest, and the incubation time was the shortest. The crystallization ability was strong due to the three factors of strengthening the interaction between ions and ion groups, decreasing the polymerization degree, and increasing the melting temperature. Further increasing the content of Li2O, the crystallization performance was obviously suppressed, because the melting temperature and the force between the cations and the anion groups decreased. 相似文献
40.
Jiming Zhou Kangdi Zhong Chentong Zhao Haiming Meng Lehua Qi 《Ceramics International》2021,47(5):6597-6607
The design of an interfacial structure is particularly important for load transfer in composites. In this paper, different amounts of carbon nanotubes (CNTs) were grafted onto the carbon fiber (CF) surface by adjusting grown temperature using injection chemical vapor deposition (ICVD). The prepared CF preform grafted with CNTs (CNTs-CF) were used to reinforce magnesium alloy by squeeze casting process. The microstructures were analyzed by means of optical microscope (OM) and scanning electron microscope (SEM), and the interlaminar shear strength (ILSS) and tensile strength of the composites were determined by double-notch shear test and tensile test. The results indicated that moderate ILSS was more conducive to improving the tensile properties of carbon fiber reinforced magnesium matrix (Cf/Mg) composites. Compared with Cf/Mg, the tensile strength of composite with CNTs increased by about 80%. For Cf/Mg composites grafted with CNTs, CNTs had the effects of delaying crack propagation and increasing energy consumption by the pull-out and bridging mechanism, which were the main reasons for improving the strength. The analysis of shear fracture surface showed that the crack propagation path can be optimized by adjusting the amounts of grafted CNTs. The presence of CNTs affects the stress distribution and consequently the crack initiation as well as the crack propagation. 相似文献