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| 1 | Synchronization of the four identical unbalanced rotors in a vibrating system of plane motion显示文摘A new mechanism is proposed to implement the synchronization of the four unbalanced rotors in a vibrating system, which consists of a main rigid frame (MRF) and two accessorial rigid frames (ARF). An analytical approach is developed to study the coupling dynamic characteristics of the four unbalanced rotors, which converts the problem of synchronization of the four unbalanced rotors into the existence and the stability of zero solutions for the non-dimensional differential equations of the angular velocity disturbance parameters (NDDEDP). The stability of zero solutions of the NDDEDP is decomposed into that of its generalized system and a system of the three first order differential equations for the disturbance parameters of the phase differences. The coupling dynamic characteristic of the four unbalanced rotors includes the inertia coupling, the stiffness coupling of angular velocity and the load torque coupling. The non-dimensional inertia coupling matrix is symmetric, the non dimensional matrix of the stiffness coupling of angular velocity is antisymmetric and its diagonal elements are all negative. Hence, the general system of the NDDEDP automatically satisfies the generalized Lyapunov equations when the non-dimensional inertia coupling matrix is positive definite and its elements are all positive. Using Routh-Hurwitz criterion the condition of stability of differential equations for the disturbance parameters of the phase differences is obtained. The load torque coupling makes the vibrating system have the dynamic characteristic of selecting motions and self-synchronization of the four unbalanced rotors arises from the dynamic characteristic of selecting motion of the vibrating system. When the two coefficients of coupling cosine effect of phase angles are all greater than 0 and the three indexes of synchronization are all far greater than 1, the vibrating system can implement an elliptical motion of the main rigid frame required in engineering. Numeric results show that the structural parameters of the proposed mechanism can guarantee the non-dimensional inertia matrix to be always positive definite. Computer simulation is carried out to verify the results of the theoretical investigation. | ZHAO ChunYu, WEN BangChun & ZHANG XueLiang School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110004, China | 2010 | Science China(Technological Sciences)2010，53，2： | 12 |
| 2 | Effect of corrosive media on galvanic corrosion of complicated tri-metallic couples of 2024 Al alloy/Q235 mild steel/304 stainless steel显示文摘Galvanic corrosion of tri-metallic couples is more complicated than that of bi-metallic couples. In this study, the effect of the pH of corrosive media on the galvanic corrosion of 2024 A1 alloy/Q235 mild steel/304 stainless steel tri-metallic couples was investigated using potentiodynamic polarization, scanning electron microscopy, scanning vibrating electrode technique and a multi-channel galvanic corrosion meter. The results show that 2024 always acts as the only anode in 3.5 wt% NaCl at pH 5.56,9.72 and 12.0, while both Q235 and 2024 act as anodes at pH 2.39 in the initial stage and then the role of Q235 changes at longer coupling time, which can be attributed to the effect of pH on the surface film of 2024. It is also found that the galvanic current density of a tri-metallic couple is the superposition of two bi-metallic couples when cathodic reactions are controlled by the diffusion of oxygen, otherwise it is smaller than that of the sum of two bi-metallic couples. The localized corrosion instead of uniform corrosion of anodic metal is accelerated by galvanic corrosion. | Linjun Shi Xiuying Yang Yingwei Song Dan Liua Kaihui Dong Dayong Shan En-Hou Han | 2019 | Journal of Materials Science & Technology2019，35，9： | 8 |
| 3 | Space Environment Simulation for Material Processing by Acoustic Levitation显示文摘Single-axis acoustic levitation of four polymer samples has been realized in air under the ground-based laboratory conditions for the purpose of space environment simulation of containerless processing.The levitation capabilities are investigated by numerical calculations based on a model of the boundary element method corresponding to our levitator and following Gor'kov and Barmatz's method.The calculated results,such as the resonant distance between the reflector and the vibrating source and the positions of levitated samples,agree well with experimental observation,and the effect of gravity on the time-averaged potential for levitation force is also revealed.As an application,the containerless melting and solidification of a liquid crystal,4-Pentylphenyl-4'-methybenzoate,is successfully accomplished,in which undercooling up to 16 K is obtained and the rotation and oscillation of the sample during solidification may result in fragmentation of the usual radiating surface growth morphology. | 解文军 魏炳波 | 2001 | Chinese Physics Letters2001，18，1： | 5 |
| 4 | Effects of boundary conditions on vibrating mode of acoustic logging dipole transducer显示文摘Acoustic transducer is an important part of acoustic well logging tool. In this paper,ANSYS software package is used to design acoustic dipole transducer and simulate vibrating mode of the dipole transducer in different mechanical boundary conditions. The results show that boundary conditions influence the number of vibrating mode in the same frequency band and the frequency value of the same vibrating mode. Several acoustic dipole transducers are designed according to the results of numerical simulation and laboratory measurements. The basic frequency of vibrating mode of experi-ment has good agreement with that of simulation. The numerical simulation plays a good guidance role in designing,producing and correctly installing the acoustic dipole transducer. | QIAO WenXiao,CHE XiaoHua & ZHANG Fei State Key Laboratory of Petroleum Resource and Prospecting,China University of Petroleum,Beijing 102249,China | 2008 | Science China Earth Sciences2008，51，S2： | 3 |
| 5 | Flow field design and process stability in electrochemical machining of diamond holes显示文摘The metal grille, commonly composed of an amount of diamond holes, has been growingly used as a key structure on stealth aircraft. Electrochemical machining(ECM) promises to be increasingly applied in aircraft manufacturing on the condition that process stability is guaranteed.In this work, a flow field model was designed to improve the process stability. This model is endowed with a variety of flow channel features, together with vibrating feeding modes. The flow field distribution on the bottom surface of the diamond hole was discussed and evaluated as well.The numerical results show that a short arc flow channel could significantly enhance the uniformity of electrolyte velocity distribution and a vibrating feeding of the cathode enables to reduce both fluctuations of the electrolyte velocity and pressure on the bottom surface of the diamond hole.Consequently, the flow field mutations were eliminated. It is verified from the experimental results that a short arc flow channel, when combined with vibrating feeding, is capable of improving machining localization and process stability markedly. What is more, the side gap on the bottom surface of the diamond hole could also be reduced by the abovementioned approach. | Zhao Jianshe Wang Feng Liu Zhuang Zhang Xiangli Gan Weimin Tian Zongjun | 2016 | Chinese Journal of Aeronautics2016，29，6： | 3 |
| 6 | Understanding the galvanic corrosion of the Q-phase/Al couple using SVET and SIET显示文摘The galvanic corrosion of the Q-phase/Al couple in 0.1 M NaCl solutions has been studied using the scanning vibrating electrode technique (SVET)f the scanning ion-selective electrode technique (SIET) and energy dispersive X-ray spectroscopy (EDX). The galvanic corrosion of the Q-phase/Al couple was found to be dependent on pH and immersion time. Current density maps obtained by SVET shows that the anodic oxidation processes emerge from Al in a localized manner in pH 2 and 6 solutions but is initiated in a uniform manner in pH 13 solution, whereas, the cathodic processes are more homogeneously distributed over the Q-phase at pH 2.6 and 13. It is seen that the Q-phase remains cathodic in the Q-phase/Al couple in acidic, neutral and alkaline solutions indicating that the galvanic polarity of the Q-phase is independent of pH. The effect of the galvanic corrosion was largest at pH 2 and 13 compared to pH 6. The pH map obtained by SIET indicates that the galvanic activity of the Q-phase/Al couple proceeds via heavy alkalization of the Q-phase surface with the generation of appreciable amounts of OH~ ions. The enrichment of Cu indicated by EDX is responsible for the observed cathodic activity of the Q-phase in the Q-phase/Al couple. | Alexander I.Ikeuba Bo Zhang Jianqiu Wang En-Hou Han Wei Ke | 2019 | Journal of Materials Science & Technology2019，35，7： | 2 |
| 7 | Theoretical, Numerical and Experimental Study on Synchronization of Three Identical Exciters in a Vibrating System显示文摘The theory on synchronization of two exciters is more widely used in engineering, while that of more than two exciters is less considered. So it is of great significant to investigate synchronization of three exciters. Firstly by introducing the average method of modified small parameters, the dimensionless coupling equations(DCE) of three exciters are derived, which convert the problem of synchronization into that of existence and stability of zero solutions for the DCE and lead to the construction on criterions of synchronization and stability in the simplified form for three exciters. Then the synchronization criterion is discussed numerically, as well as the abilities of synchronization and stability, some results thereof indicate that the synchronization ability increases with the increase of the coupling moment among three exciters, but decreases with that of their phase differences. Finally, an experiment on synchronization with three exciters is carried out. Through the comparison and analysis of experimental data on phase differences among three exciters, responses of system, and phases of three exciters recorded by high-speed camera, the parameters of system satisfying the above two criterions can ensure the synchronous and stable operation of three exciters. As a result, the average method of modified small parameters can be used as a theoretical apparatus studying reasonably the synchronization mechanism of three exciters, it is also proved to be useful and feasible by numeric and experiment. The present research lays the foundation and guidance for the establishment of synchronization theory system with multi-exciter and engineering design. | ZHANG Xueliang WEN Bangchun ZHAO Chunyu | 2013 | Chinese Journal of Mechanical Engineering2013，26，4： | 2 |
| 8 | Mechanical quality factor of high-overtone bulk acoustic resonator显示文摘Mechanical quality factor Qm is a key characteristic parameter of High-overtone bulk acoustic resonator(HBAR). The effects of structure parameter(thickness) and perfor?mance parameters(characteristic impedance and mechanical attenuation factor) of substrate,piezoelectric film and electrode constituting HBAR on Qm are carried out. The relationships between Qm and these parameters are obtained by a lumped parameter equivalent circuit instead of distributed parameter equivalent circuit near the resonance frequency, and the an?alytical expressions oi Qm are given. The results show that Qm increases non-monotonically with the continuous increase of the substrate thickness for HBAR with certain piezoelectric film thickness, and it approaches to the substrate material mechanical quality factor as the substrate thickness is large. Qm decreases wavily with the continuous increase of the piezoelectric film thickness for HBAR with certain substrate thickness. Sapphire and YAG with low mechanical loss are appropriate as the substrate to get a larger Qm- The electrode loss must be considered since it can reduce Qm- Compared with Au electrode, A1 electrode with lower loss can obtain higher Qm when the appropriate electrode thickness is selected. In addition, Qm decreases with the increase of frequency. These results provide the theoretical basis for optimizing the parameters of HBAR and show that trade-oflFs between Qm and must be considered in the design because their changes are often inconsistent. | LI Jian LIU Mengwei LI Junhong MA Jun WANG Chenghao | 2016 | Chinese Journal of Acoustics2016，35，3： | 2 |
| 9 | Breakdown of Energy Equipartition in Vibro-Fluidized Granular Media in Micro-Gravity显示文摘We present a micro-gravity experimental study of intermediate number density vibro-fluidized inelastic spheres in a rectangular container.Local velocity distributions are investigated,and are found to deviate measurably from a symmetric distribution for the velocity component of the vibrating direction when dividing particles along the vibration direction into several bins.This feature does not exist in the molecular gas.We further study the hydrodynamic profiles of pressures p and temperatures T in positive and negative components,such as p+y and p-y and T+y and T-y,in accordance with the sign of velocity components of the vibrating direction.Along vibration direction,granular media are found to be not only inhomogeneous and anisotropic,but also different greatly in positive and negative components.Energy equipartition breaks down in this case. | 陈延佩 Pierre Evesque 厚美瑛 | 2012 | Chinese Physics Letters2012，29，7： | 1 |
| 10 | Influence of vibration on granular flowability and its mechanism of aided flow显示文摘Regarding flowing granular media as weak transverse isotropic media, the phase velocity expressions of wave P, wave SH and wave SV were deduced, the propagation characteristics of waves in flowing granular media were analyzed. The experiments show that vibration has great influence on granular fluidity. The wavefront of wave P is elliptic or closely elliptic, the wavefront of wave SH is elliptic, and the wavefront of wave SV is not elliptic. Wave propagation in the granular flowing field attenuates layer after layer. The theory and experiment both substantiate that the density difference is the key factor which leads to the attenuation of vibrating energy. In terms of characteristics of wave propagation one can deduce that vibrating waves have less influence on flowability of granules when the amplitude and frequency are small. However, when the amplitude and frequency increase gradually, the eccentricity of ellipsoid, the viscosity resistance and inner friction among granules, and shear intensity of granules decrease, and the loosening coefficient of granules increases, which shows the granules have better flowability. | WU Ai xiang,SUN Ye zhi,LI Jian hua (College of Resources, Environment and Civil Engineering, Central South University, Changsha 410083, China) | 2001 | Journal of Central South University of Technology2001，8，4： | 1 |
| 11 | Parametric Modeling of Electromagnetically Induced Vibration Processes Occurring Within Induction Systems显示文摘A continuum based model is presented which identifies a favorable set of operational conditions whereby an effective and efficient electromagnetically induced vibratory motion can proceed within an induction system.Specifically,an analytical assessment is presented for the electromagnetic field and the electromagnetically induced acoustic field,with parametric factors incorporated into the model to permit a normal modes solution for the acoustic field which here is sensitive to the compliance of both the molten metal and the wall,as well as electromagnetic properties of the metal.A parametric analysis is presented which identifies the importance of matching the mechanical impedances of the melt-wall configuration so that the generation of acoustic energy within the melt system can be more effectively utilized.Relatively straight-forward calculations,presented for the acoustic field,may provide a more computationally efficient means for implementing process simulation studies for these systems. | PETRYKOWSKI John C. SHI Yinghui | 2012 | Journal of Iron and Steel Research(International)2012，19，S2： | 1 |
| 12 | 茧响显示文摘以机械枯燥的都市台北为背景,"茧响"作为难得的有机形式空间异军突起,它是工业昆虫们的卵房,昆虫需要破茧而出,经历后工业时代的蜕变。根据人类已掌握的"当地知识",采用灵活的竹结构,通过高水平的即兴创作,结合昆虫建筑学,这一开放式格局的建筑最终落成。 | | 2014 | 世界建筑导报2014，，2： | 0 |
| 13 | WaveBehaviorofVibratingFluidizedBeds显示文摘WaveBehaviorofVibratingFluidizedBedsWangTingjie(王亭杰),WangZhanwen(汪展文)JinYong(金涌),YuZhiqing(俞芷青)DepartmentofChemicalEngineerin... | 王亭杰 汪展文 金涌 俞芷青 | 1996 | Tsinghua Science and Technology1996，1，4： | 0 |
| 14 | WHAT CAUSE THE NONPROPAGATING SOLITONS TO MOVE显示文摘Two spherical solitons are vibrating along the direction perpendicular to a line joining the cores of them.The interactive forces that will be attractive or repelling depending on their phase are given. | 王本仁 魏荣爵 | 1989 | Chinese Physics Letters1989，6，9： | 0 |
| 15 | Effects of Microaddition of Ce on the Induced Magnetic Anisotropy of Amorphous Fe_(78)Si_9B_(13)显示文摘Controlling the magnetic anisotropy ofmagnetic material is extremely important forany technological applications.Fe78Si9 B13amorphous alloy has been chosen for investi-gation.Although the alloy might be a goodsoft magnetic material,it might not be ideal ifthe quenching processing is carried out | Wu Yu Yu Jing He Yeqing University of Science and Technology,Beijing | 1990 | Rare Metals1990，10，1： | 0 |
| 16 | ON STABILIZATION AND POLE ASSIGNMENT FOR VIBRATING ELASTIC SYSTEMS OF SLENDER VEHICLE显示文摘If we neglect the aerodynamic and internal damping effects, and take angular velocity feedback control law for the control force, then, without losing generality, the vibrating elastic system of a slender vehicle can be described by the following partial | 朱广田 刘彦群 | 1987 | Chinese Science Bulletin1987，32，12： | 0 |
| 17 | CHARACTERISTIC CURVES OF M-H AND COEXISTENCE OF MAGNETISM WITH SUPERCONDUCTIVITY FOR HIGH T_c SUPERCONDUCTORS REBa_2Cu_3OT_(7-x)显示文摘Some high Tc superconductors REBa2Cu3O7-x(RE=Sm,Eu,Gd,Dy,Ho,Er,Tm) with zero resist-ance temperatures were about 90K have been prepared.The effect of magnetic rare earth ions on the transi-tion temperatures is not very great,but their magnetic behaviours are different from each other.Themagnetization loops of these compounds have been measured at 77K.The coexistence of superconductivitywith magnetic ordering (COSM) found in the samples with RE=Gd,Dy,Ho,Er,Tm,indicates that thereare two possible ways of coexistence in the samples.These expertments show that the relation ofparamagnetism to the atomtc number of rare earth elements for these superconductors is similar to that ofrare earth ions in some paramagnetic salt crystals,which indicates that the magnetism of the samples origi-nates from the local magnetic moments of rare earth ions.In some samples there is antiferromagnetie orderingat low temperatures,and the effective Bohr magneton numbers are consistent with that of free rare earth ions.Some superconducting parameters including the critical current density are calculated according toGinzburg-Landau theory and the critical state model. | 孙长勇 苏文辉 刘宏建 周建十 王法堂 张裕普 | 1990 | Journal of Rare Earths1990，8，2： | 0 |
| 18 | THEORETICAL EXPLANATION OF SPIN REORIENTATION IN DyTiFe_(11) COMPOUND显示文摘DyTiFe11 compound is a ferromagnetic substance.It has tetragonal body-centered ThMn12-typecrystallographic structure.At room temperature,the easy magnetization direction is the c-axis.A spinreorientation begins to appear at about 175K.The contribution of Fe sublattice to magnetocrystallineanisotropy was determined by experiments and that of Dy sublattice was obtained by using single ion modelcalculation.Results show that the spin reorientation arises from the competition of anisotropy between Fe andDy sublattices. | 裴谐第 杨应昌 查元勃 孙弘 孔麟书 | 1990 | Journal of Rare Earths1990，8，2： | 0 |
| 19 | THE HAPHAZARD PACKING OF EQUAL SPHERES显示文摘Ⅰ. INTRODUCTION Since the last century, a lot of scholars in various fields, including the well-known scientists Woolaston, Thomson (Lord Kelvin) and Bernal were interested in the packing of equal spheres, as it is of very important significance in theory and practice. | 叶大年 韩成 曾荣树 | 1987 | Chinese Science Bulletin1987，32，12： | 0 |
| 20 | A MODEL IDENTIFICATION METHOD OF VIBRATING STRUCTURES FROM INCOMPLETE MODAL INFORMATION显示文摘AMODELIDENTIFICATIONMETHODOFVIBRATINGSTRUCTURESFROMINCOMPLETEMODALINFORMATIONZhengXiaoping(郑小平)YaoZhenhan(姚振汉)QuShisheng(蘧时胜)... | 郑小平 姚振汉 蘧时胜 | 1995 | Applied Mathematics and Mechanics(English Edition)1995，16，10： | 0 |
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