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A semi-active smart tuned mass damper for drive shaft
Q.-C. Cai,J.-H. Park,C.-H. Lee,J.-L. Park,D.-Y. Yoon 한국소음진동공학회 2011 한국소음진동공학회 학술대회논문집 Vol.2011 No.10
Tuned mass damper is widely used in many applications of industry. The main advantage of tuned mass damper is that it can increase the damping ratio of system and reduce the vibration amplitude. Meanwhile, the natural frequency of system will be divided by two peaks, and the peak speeds are closely related to the mass and the stiffness of auxiliary mass system added. In addition, the damping ratio will also affect the peak frequency of the dynamic response. In the present research, the nonlinear mechanical characteristics of rubber is investigated and put into use, since it is usually manufactured as the spring element of tuned mass damper. By the sense of the nonlinear stiffness as well as the damping ratio which can be changed by preload applied on, the shape memory alloy is proposed to control the auxiliary mass system by self-optimizing. Supported by the experiment data of rubber, the 1 DOF theoretical model and finite element model based on computer simulation are implemented to perform the feasibility of the proposed semi-active tuned mass damper working on the drive shaft.
SIMPLIFIED DYNAMICS MODEL FOR AXIAL FORCE IN TRIPOD CONSTANT VELOCITY JOINT
Q.-C. CAI,K.-H. LEE,W.-L. SONG,C.-H. LEE,Y. LEE 한국자동차공학회 2012 International journal of automotive technology Vol.13 No.5
Tripod constant velocity (TCV) joints are common components in automotive and mechanical applications. The benefits of the TCV joint are its high plunge capacity and high torque capacity. During power transmission, the friction inside the joint generates an axial force according to the kinematics. This force causes noise and vibration problems. In this study, a simplified multi-body dynamic model based on a phenomenological TCV joint friction model is developed. This model considers the generated axial force (GAF) of a TCV joint with different lubricate conditions. The efficiency and accuracy are verified by comparison with other prediction models and experiments. Thus, this model can be used to design and control the manufacture process of TCV joints.
Y.G. Xiao,M.H. Tang,Y. Xiong,J. C. Lin,C.P. Cheng,B. Jiang,H.Q. Cai,Z.H. Tang,X.S. Lv,X.C. Gu,Y.C. Zhou 한국물리학회 2012 Current Applied Physics Vol.12 No.6
The surface potential and drain current of double-gate metal-ferroelectric-insulator-semiconductor (MFIS) field-effect transistor were investigated by using the ferroelectric negative capacitance. The derived results demonstrated that the up-converted semiconductor surface potential and low subthreshold swing S = 34 (<60 mV/dec) can be realized with appropriate thicknesses of ferroelectric thin film and insulator layer at room temperature. What’s more, a reduction gate voltage about 260 mV can be reached if the ON-state current is fixed to 600 mA/mm. It is expected that the derived results can offer useful guidelines for the application of low power dissipation in ongoing scaling of FETs.
Controllable seeding of single crystal graphene islands from graphene oxide flakes
Li, Q.,Zhang, C.,Lin, W.,Huang, Z.,Zhang, L.,Li, H.,Chen, X.,Cai, W.,Ruoff, R.S.,Chen, S. Pergamon Press ; Elsevier Science Ltd 2014 Carbon Vol.79 No.-
Graphene oxide (G-O) flakes were used to seed the growth of single crystal graphene islands by chemical vapor deposition (CVD) on Cu foil. Such islands have the G-O seed (which converts to a 'reduced graphene oxide' (rG-O) seed due to the CVD growth conditions used) roughly in the center of the islands. The lateral growth of such single crystal graphene islands was studied by carbon isotope labeling and Raman spectroscopy, scanning and transmission electron microscopy and selected area electron diffraction. By changing the concentration of G-O in the aqueous dispersion used to deposit the G-O flakes onto the Cu foil by dip-coating, the size of the seeded graphene islands could be precisely controlled on the Cu foil. The crystal orientation of the single crystal graphene islands was found to be identical to that of the G-O seeds.
Su, Y.,Liu, C.W.,Liu, L.,Ye, C.H.,Cao, W.Q.,Huang, Y.Q.,Zheng, J.,Cai, D.Y.,Olowofeso, O. Asian Australasian Association of Animal Productio 2006 Animal Bioscience Vol.19 No.4
The genetic polymorphism and relationships of Muscovy, Cherry Valley Meat ducks, Partridge ducks and their crossbreds $F_1$ and $F_2$, respectively, were studied using a random amplified polymorphic DNA (RAPD) technique. The results showed that RAPD markers were effective for the analysis of genetic relationships among ducks. Amplification with 20-primers gave 760 reproducible amplified fragments. The percentage of polymorphic marker band was 74.70%, which indicates that the RAPD technique had higher efficiency of polymorphism detection and sensitivity in studying the genetic variations among ducks and showed that the genetic polymorphism was abundant between two species of duck populations. The average index of genetic distance in hybrid $F_2$ was 0.2341 and higher than that of its parents, which indicates that the genetic diversity was improved by crossbreeding with Muscovy.