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Search Results: 1 - 10 of 51146 matches for " Xiaoyong Wei "
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Design of a Novel MEMS Gyroscope Array
Wei Wang,Xiaoyong Lv,Feng Sun
Sensors , 2013, DOI: 10.3390/s130201651
Abstract: This paper reports a novel four degree-of-freedom (DOF) MEMS vibratory gyroscope. A MEMS gyroscope array is then presented using the novel gyroscope unit. In the design of the proposed 4-DOF MEMS vibratory gyroscope, the elements of the drive-mode are set inside the whole gyroscope architecture, and the elements of sense-mode are set around the drive-mode, which thus makes it possible to combine several gyroscope units into a gyroscope array through sense-modes of all the units. The complete 2-DOF vibratory structure is utilized in both the drive-mode and sense-mode of the gyroscope unit, thereby providing the desired bandwidth and inherent robustness. The gyroscope array combines several gyroscope units by using the unique detection mass, which will increase the gain of sense-mode and improve the sensitivity of the system. The simulation results demonstrate that, compared to a single gyroscope unit, the gain of gyroscope array (n = 6) is increased by about 8 dB; a 3 dB bandwidth of 100 Hz in sense-mode and 190 Hz in drive-mode are also provided. The bandwidths of both modes are highly matched with each other, providing a bandwidth of 100 Hz for the entire system, thus illustrating that it could satisfy the requirements in practical applications.
A Comparative Study of Heat Transfer Coefficients for Film Condensation
Xiaoyong WEI,Xiande FANG,Rongrong SHI
Energy Science and Technology , 2012, DOI: 10.3968/j.est.1923847920120301.152
Abstract: Film condensation heat transfer has wide applications in a variety of industrial systems. A number of film condensation heat transfer correlations (FCHTCs) have been proposed. However, their predictions are often inconsistent. This paper presents a comparative study of existing FCHTCs. Totally 1214 experimental data points are obtained from 10 published papers, and 14 FCHTCs are reviewed, among which four correlations are used for horizontal flow outside smooth tubes, three for flow on vertical surfaces of plates or tubes, two for flow inside smooth tubes either vertically or horizontally, and five for horizontal flow inside smooth tubes. 13 FCHTCs are compared with the experimental data. There are three FCHTCs for horizontal flow inside smooth tubes having a mean absolute relative deviation (MARD) less than 26%, among which the best one has an MARD of 22.2%. More efforts should be made to develop better correlations. Key words: Correlation; Heat transfer; Film; Condensation
Microstructure and properties of Ga-modified 0.7BiFeO3-0.3BaTiO3 solid solution
XiaoHui Liu,Zhuo Xu,ShaoBo Qu,XiaoYong Wei,JiangLi Chen
Chinese Science Bulletin , 2007, DOI: 10.1007/s11434-007-0408-5
Abstract: Binary solid solutions 0.7Bi (Ga x Fe1 x )O3-0.3BaTiO3 (x = 0, 0.025, 0.05, 0.1) ceramics were prepared by traditional ceramic process. All the ceramic samples showed single perovskite phase except the sample with x = 0.1. The effects of gallium doping on microstructure, ferromagnetic, ferroelectric, dielectric properties and conductivity were investigated. The results indicated that Ga-dopant could improve the sintering ability of the solid solution when the Ga content x was below 0.05. When x was over 0.05, the sintering ability of the solid solution was weakened, and the phase structure of 0.7BiFeO3-0.3BaTiO3 solid solution changed from rhombohedral phase into tetragonal ferroelectric phase. The electrical resistivity increased with the Ga content increasing. Both ferroelectricity and ferromagnetism were observed in all the ceramic samples. With the Ga content increasing, the remanent magnetization M r increased and the magnetic coercive field H c decreased. However, the remanent polarization P r fluctuated, increasing firstly and decreasing later.
On the Mechanism of the Impact of Relational Embeddedness on Firm''s Technological Innovation:The Mediation and Moderation Effects of Organizational Learning Capability
关系嵌入强度对企业技术创新绩效的影响机制研究——基于组织学习能力的中介性调节效应分析

Wei Jiang,Zheng Xiaoyong,
魏江
,郑小勇

浙江大学学报(人文社会科学版) , 2010,
Abstract: Relational embeddedness can make sense to both incremental innovation and radical innovation, but the mechanisms of the two innovations are different. As far as incremental innovation is concerned, organizational learning capability mainly acts as the mediator between the strong tie and incremental innovation, while it mainly acts as the moderator between the weak tie and incremental innovation. In the case of radical innovation, organizational learning capability can only act as the mediator for the strong tie, but for the weak tie it can be both the mediator and moderator.
Fisher’s linear discriminant (FLD) and support vector machine (SVM) in non-negative matrix factorization (NMF) residual space for face recognition
Changjun Zhou,Xiaopeng Wei,Qiang Zhang,Xiaoyong Fang
Optica Applicata , 2010,
Abstract: A novel method of Fisher’s linear discriminant (FLD) in the residual space is put forward for the representation of face images for face recognition, which is robust to the slight local feature changes. The residual images are computed by subtracting the reconstructed images from the original face images, and the reconstructed images are obtained by performing non-negative matrix factorization (NMF) on original images. FLD is applied to the residual images for extracting FLD subspace and the corresponding coefficient matrices. Furthermore, features are obtained by mapping the residual image to FLD subspace. Finally, the features are utilized to train and test support vector machines (SVMs) for face recognition. The computer simulation illustrates that this method is effective on the ORL database and the extended Yale face database B.
Syringic Acid Extracted from Herba dendrobii Prevents Diabetic Cataract Pathogenesis by Inhibiting Aldose Reductase Activity
Xiaoyong Wei,Dan Chen,Yanchun Yi,Hui Qi
Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/426537
Abstract:
Improved Performance of the Piezoelectric Monomorph with Perpendicular Electrode Connections for Sensing and Energy Harvesting
Ming Ma,Zhenrong Li,Xiaoyong Wei,Zhuo Xu,Xi Yao
Smart Materials Research , 2013, DOI: 10.1155/2013/957460
Abstract: Piezoelectric monomorph, which has only one element, is a potential structure for piezoelectric applications in some extreme conditions. But as the restriction of the strain neutral layer, the traditional parallel electrode connection is not effective for sensing and energy harvesting. In this paper, perpendicular electrode connections were designed to utilize the nonuniform shear piezoelectric effect in the cross section of the monomorph, which made the monomorph avoid the restriction of the strain neutral layer. The PZT5 ceramic monomorph was preliminarily studied in this experiment. By comparing seven forms of perpendicular electrode connections with the traditional parallel electrode connection, the whole superposed perpendicular electrode connection is considered as the optimal output way for the monomorph. It can produce 13?V peak-to-peak (pk-pk) voltage in open circuit and 14.56?μW maximum power with the matching resistance, which are much more than the parallel electrode connection 0.78?V and 0.14?μW. 1. Introduction Piezoelectric cantilever is widely used in the piezoelectric device for sensing and energy harvesting [1–6]. At room temperature and ambient pressure, unimorph and bimorph, which utilize the lateral extensional piezoelectric effect, are considered as a promising solution for sensing and energy harvesting [7, 8]. But when both of the above composite structures are used under the relative tough environment, such as high temperature and high pressure or low temperature and low pressure, the stability and performance of the device will be lower as the thermal-oxidative degradation and the low temperature brittleness of the bonding materials between different components. Even in the normal situation, the internal stresses and the permanent strain in the bonding layer will lead to the rapid deterioration of the device after long time using [9]. As for the simplest transducer that has only one piezoelectric component, the piezoelectric monomorph avoids the bonding issues and is considered as the only solution in the extreme conditions. But the existence of the strain neutral layer, which is in the middle of the thickness of the piezoelectric element, neutralizes the positive and negative induced charges [10]. As a result, with the traditional parallel electrode connection, the monomorph is not effective in the piezoelectric applications. In order to improve the performance of the monomorph, many studies have been focused on the nonuniform polarization inside the piezoelectric materials. Based on the nonuniform distribution of the electric
Ultrafast spectroscopy of quasiparticle dynamics in cuprate superconductors
Wei Li,Chunfeng Zhang,Xiaoyong Wang,Jak Chakhalian,Min Xiao
Physics , 2014, DOI: 10.1016/j.jmmm.2014.06.056
Abstract: Ultrafast pump-probe spectroscopy is a powerful tool to study the nonequilibrium dynamics in high-Tc cuprate superconductors. The photo-induced quasiparticle (QP) dynamics revealed by pump-probe spectroscopy are sensitive to the near-Fermi level electronic structures. Here we review several selected examples to illustrate the enduring challenges including pairing glue, phase separation, and phase transitions in cuprate superconductors. We also present the data obtained on thin films of YBa2Cu3O7-{\delta} in connection to these issues.
More ferroelectrics discovered by switching spectroscopy piezoresponse force microscopy?
Hongchen Miao,Chi Tan,Xilong Zhou,Xiaoyong Wei,Faxin Li
Physics , 2014, DOI: 10.1209/0295-5075/108/27010
Abstract: The local hysteresis loop obtained by switching spectroscopy piezoresponse force microscopy (SS-PFM) is usually regarded as a typical signature of ferroelectric switching. However, such hysteresis loops were also observed in a broad variety of non-ferroelectric materials in the past several years, which casts doubts on the viewpoint that the local hysteresis loops in SS-PFM originate from ferroelectricity. Therefore, it is crucial to explore the mechanism of local hysteresis loops obtained in SS-PFM testing. Here we proposed that non-ferroelectric materials can also exhibit amplitude butterfly loops and phase hysteresis loops in SS-PFM testing due to the Maxwell force as long as the material can show macroscopic D-E hysteresis loops under cyclic electric field loading, no matter what the inherent physical mechanism is. To verify our viewpoint, both the macroscopic D-E and microscopic SS-PFM testing are conducted on a soda-lime glass and a non-ferroelectric dielectric material Ba0.4Sr0.6TiO3. Results show that both materials can exhibit D-E hysteresis loops and SS-PFM phase hysteresis loops, which can well support our viewpoint.
A Note on the Structure of Affine Subspaces of L2(Rd)  [PDF]
Fengying Zhou, Xiaoyong Xu
Advances in Pure Mathematics (APM) , 2015, DOI: 10.4236/apm.2015.52008
Abstract:

This paper investigates the structure of general affine subspaces of L2(Rd) . For a d × d expansive matrix A, it shows that every affine subspace can be decomposed as an orthogonal sum of spaces each of which is generated by dilating some shift invariant space in this affine subspace, and every non-zero and non-reducing affine subspace is the orthogonal direct sum of a reducing subspace and a purely non-reducing subspace, and every affine subspace is the orthogonal direct sum of at most three purely non-reducing subspaces when |detA| = 2.

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