http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Nannan Zhao,Chunyan Ban 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.10
This paper investigated the microstructure, tensile and electrical properties of an equal channel angular pressed 6063 Al alloyat temperatures ranging from room temperature (RT) to 300 ℃. Additionally, a two-step temperature schedule (TST) wasapplied to improve the combined property of the low-alloyed Al–Mg–Si alloy. The results suggested that only processing atRT and TST led to a reduction of the grain size and an increase of strength with increasing number of passes, whereas fourpassprocessing at TST condition produced a better grain refinement and higher strength compared to the RT counterpart. Detailed analysis reveals that apart from the grain refinement, high-density dislocations and formation of nanoscale precipitatesplay the dominant roles in strengthening. These microstructural features provide the four-pass TST sample exceptionalincrease in strength about 67 MPa compared to RT counterpart. Besides, precipitation of solutes in form of numerousnanoscale precipitates can purify the Al matrix in the TST samples, resulting in the improved electrical conductivity ascompared to RT sample. The TST method as a new strategy can improve strength and electrical conductivity by controllingthe nanosized precipitates in an ultrafine-grained structure, which indeed provides an opportunity for low-alloyed Al–Mg–Sialloys to obtain the better combination properties.
Bearing Fault Diagnosis of Single-Channel Data by a 3D DCN with Bilinear LBP and Modified KPCA
Zhao Yunji,Zhou Menglin,Wang Li,Xu Xiaozhuo,Zhang Nannan 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.5
The vibration signal has the characteristics of nonlinear and non-stationary, and the distribution of fault feature information contained in it is not concentrated. In addition, the nonlinear coupling of fault-adjacent features in space is strong, resulting in poor spatial separability of fault information. At the same time, the fault diagnosis algorithm based on a convolutional neural network, cannot fully obtain the spatial distribution information of fault data due to its fixed geometric structure of convolution kernel. In order to solve the above problems, a novel fault diagnosis method for single-channel bearing fault data is proposed. First, the improved bilinear local binary pattern algorithm is used to extract time series constraint information between different points of the original fault data. Then, considering the strong nonlinear coupling of fault data adjacent features in space, this paper proposes the modified kernel principal component analysis. It obtains information on fault data in high-dimensional space by calculating the kernel space mapping matrix of different fault categories, kernelizing the sample matrix, and mapping the kernel space mapping matrix. Finally, based on this information, a 3D deformable convolution network (DCN) is introduced to obtain the spatial distribution information of fault data. DCN can adaptively adjust the shape of its own convolution kernel according to the input, which can obtain more comprehensive information and further improve the spatial separability of fault data. Experiments on CWRU and XJTU-SY both achieved 100% diagnostic accuracy, which shows the superiority of the proposed method.
Nannan Wang,Yifu Zhang,Tao Hu,Yunfeng Zhao,Changgong Meng 한국물리학회 2015 Current Applied Physics Vol.15 No.4
Ultrahigh-aspect-ratio V2O5 nanowires were successfully prepared using [VO(O2)2(OH2)]- as the starting material by a template-free hydrothermal route without the addition of organic surfactant or inorganic ions. The prepared samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmet-Teller (BET), cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD). The results revealed that the peroxovanadium (V) complexes can be easily transformed to V2O5 nanowires by this hydrothermal route. The uniform nanowires were with width about 50 nm and length about dozens of micron. The BET analysis showed the V2O5 nanowires had a high specific surface area of 25.6 m2 g-1. The synthesized V2O5 nanowires performed a high capacitance of 351 F g-1 when used as supercapacitor electrode in 1 mol L-1 LiNO3.
Tang, Lijun,Zhao, Guoyou,Wang, Nannan Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.11
The colorimetric and fluorescent cyanide recognition properties of 2-[(9-ethyl-9H-carbazol-3-yl)methylene]-propanedinitrile (1) in $CH_3CN-H_2O$ (2/1, v/v, HEPES 10 mM, pH = 7.0) solution were evaluated. The optical recognition process of probe 1 exhibited high sensitivity and selectivity to cyanide ion with the detection limit of $2.04{\times}10^{-6}$ M and barely interfered by other coexisting anions. The sensing mechanism of probe 1 is speculated to undergo a nucleophilic addition of cyanide to dicyanovinyl group present in compound 1. The colorimetric and fluorescent dual-modal response to cyanide makes probe 1 has a potential utility in cyanide detection.
Wence Xu,Zhao Cao,Rui Ma,Nannan Wu,Shunli Ouyang 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.3
Slag glass-ceramics doped with different proportions of CeO2 were prepared by fusion casting method using iron tailings andfly ash as raw materials. The effect of CeO2 on the activation energy and crystallization pattern of glass-ceramics under theeffect of ohmic thermal radiation and microwave radiation was investigated. The experimental results show that thecrystallization activation energy of glass-ceramics gradually increases with the addition of CeO2, and the diopside crystallizationis suppressed. Compared with conventional heat-treated samples, microwave irradiation effectively reduces the glass transitiontemperature, mainly depending on the enhanced crystallization kinetics by microwave non-thermal effects. Further analyzedby Raman spectroscopy, the microwave effect promoted the combination of Ce4+ with [SiO4] to generate fully depolymerizedQ0, inhibited the generation of Q2 and Q3, and increased the glass stability.
Hong-Yan Zhao,Wei Liu,Yi Wang,Nannan Dai,Jian-Hong Gu,Yan Yuan,Xue-Zhong Liu,Jian-Chun Bian,Zong-Ping Liu 대한수의학회 2015 Journal of Veterinary Science Vol.16 No.3
Exposure to cadmium (Cd) induces apoptosis in osteoblasts (OBs); however, little information is available regarding the specific mechanismsof Cd-induced primary rat OB apoptosis. In this study, Cd reduced cell viability, damaged cell membranes and induced apoptosis in OBs. We observed decreased mitochondrial transmembrane potentials, ultrastructure collapse, enhanced caspase-3 activity, and increasedconcentrations of cleaved PARP, cleaved caspase-9 and cleaved caspase-3 following Cd treatment. Cd also increased the phosphorylationof p38-mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinases (ERK)1/2 and c-jun N-terminal kinase (JNK) in OBs. Pretreatment with the caspase inhibitor, N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, ERK1/2 inhibitor (U0126), p38 inhibitor(SB203580) and JNK inhibitor (SP600125) abrogated Cd-induced cell apoptosis. Furthermore, Cd-treated OBs exhibited signs of oxidativestress protection, including increased antioxidant enzymes superoxide dismutase and glutathione reductase levels and decreased formationof reactive oxygen species. Taken together, the results of our study clarified that Cd has direct cytotoxic effects on OBs, which are mediatedby caspase- and MAPK pathways in Cd-induced apoptosis of OBs.
Guangshuo Wang,Dexing Zhao,Nannan Li,Yingzhe Zeng,Shuai Han,Yingying Ma,Xufeng Dong,Ruitao Yu 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.79 No.-
In this study,flower-like Fe3O4 microspheres with hierarchical structure were prepared by a one-stepsolvothermal method, and the obtainedflower-like Fe3O4 microspheres were adopted as a newmagnetorheological (MR) material to prepare a uniform MR suspension with high performances. Thesynthesized samples were systematically examined using FE-SEM, TEM, TGA, XRD, XPS, BET and VSM. The preparedflower-like Fe3O4 microspheres-based MRfluid indicated typical MR properties, asevidenced by the fact that shear stress, yield stress, viscoelastic storage modulus and loss modulus of MRfluid strongly depended on magneticfield strengths. Specifically, the resultant MRfluid showed goodsedimentation stability with sedimentation ratio of 86.5% in the settling period. The excellentsedimentation stability could be attributed to the uniqueflower-like hierarchical structure, high specificsurface area and the reduced particle-fluid density mismatch.
Yan Yan,Libing Wu,Nannan Zhao,Ruiyan Zhang 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.3
This paper is concerned with the problem of adaptive asymptotic tracking fault-tolerant control (FTC) for uncertain nonlinear systems with actuator faults and event-triggered inputs. Firstly, fault-tolerant controller is designed to effectively compensate the unknown actuator failures by constructing the proper parameter updated laws. Then, the event-triggered strategy based on the relative threshold method is applied to the proposed adaptive fault-tolerant controller. Furthermore, it is proved that all the closed-loop signals are uniformly bounded and the tracking error can asymptotically converge to zero. Finally, the simulation results are given to demonstrate the effectiveness of the presented control scheme.
Gaolin Wang,Bowen Wang,Nannan Zhao,Dianguo Xu 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.2
This paper presents a novel filtering method for speed measurements to improve the low-speed performance of the direct-drive permanent magnet traction machines for elevators. Based on the theory of nonlinear tracking differentiator (NTD), this method, which can act as a high performance filter of a raw speed signal, obtains a more accurate speed feedback signal when applying a low-resolution encoder. In addition, it can relieve the interference caused by the position derivative for speed sampling. By analyzing the frequency response of the NTD, the influence of its parameters on the performance of the speed filtering is investigated. Compared with different types of low-pass filters, the proposed method shows a shorter time delay and a stronger ability in terms of noise suppression when the parameters are selected carefully. In addition, when using the measured speed signal through a nonlinear tracking differentiator as the feedback of the system, the motor runs more steadily at low speeds. As a result, the riding comfort of a direct-drive elevator can be improved. The feasibility of the proposed strategy was verified on an 11.7kW elevator traction machine using a commercial inverter.