Dumb-bell Shaped Magnetostrictive/Piezoelectric Transducer

Jianzhong Li,Yumei Wen,Ping Li 한국자기학회 2010 한국자기학회 학술연구발표회 논문개요집 Vol.2010 No.12

Prediction of aspect ratio of a micro hole drilled by EDM

Li Jianzhong,Yin Guoqiang,Wang Cong,Guo Xuejie,Yu Zuyuan 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.1

Micro electrical discharge machining (EDM) has the ability to drill micro holes with high accuracy in metallic materials. The aspect ratio of a micro hole generated by micro EDM is usually higher than those by other processes such as etching, mechanical drilling, and laser. However, it was found that the drilling speed of micro EDM slows down and even stops when the aspect ratio of a micro hole reaches a certain value. To understand this phenomenon, a theoretical model is proposed based on the fluid mechanics and surface tension. Experiments under different machining conditions are carried out to verify this model. Experimental results agree with the theoretical values, which indicate the validity of the proposed model. The difference between the theoretical values and the real values might be caused by debris, temperature and rotating of electrode in the discharge gap, which are ignored in the model.

Asymmetric Multiple-Image Encryption Based on Octonion Fresnel Transform and Sine Logistic Modulation Map

Jianzhong Li 한국광학회 2016 Current Optics and Photonics Vol.20 No.3

A novel asymmetric multiple-image encryption method using an octonion Fresnel transform (OFST) anda two-dimensional Sine Logistic modulation map (2D-SLMM) is presented. First, a new multiple-imageinformation processing tool termed the octonion Fresneltransform is proposed, and then an efficient methodto calculate the OFST of an octonion matrix is developed. Subsequently this tool is applied to processmultiple plaintext images, which are represented by octonion algebra, holistically in a vector manner. Thecomplex amplitude, formed from the components of the OFST-transformed original images and modulatedby a random phase mask (RPM), is used to derive the ciphertext image by employing an amplitude- andphase-truncation approach in the Fresnel domain. To avoid sending whole RPMs to the receiver side fordecryption, a random phase mask generation method based on SLMM, in which only the initial parametersof the chaotic function are needed to generate the RPMs, is designed. To enhance security, the ciphertextand two decryption keys produced in the encryption procedure are permuted by the proposed SLMM-basedscrambling method. Numerical simulations have been carried out to demonstrate the proposed scheme'svalidity, high security, and high resistance to various attacks.

Matric Suction Creep Characteristics of Reticulated Red Clay

Jianzhong Li,Yuanli Yang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.10

Matric suction creep is the creep of unsaturated soil caused by loading constant matric suction. Matric suction creep characteristics of reticulated red clay with constant net confing pressure and step-loading matric suction was studied using stress-controlling unsaturated triaxial test apparatus. Test and analysis results show that: (1) with constant net confining pressure, axial and radial strain of the clay caused by creep due to matric suction increases obviously; (2) the increments of axial strain of the clay, caused by creep due to matric suction under constant net confining pressure, is not the same as that of radial strain, and the absolute value of radial strain is bigger than that of axial strain; (3) creep strain produced by the same amount of matric suction decreases as the increasing of the matric suction during step loading creep, which means that matric suction makes the clay hard; and (4) the creep strain-time curves of both axial and radial creep can be simulated very well by exponential decay function, and the parameters of the function are matric suction depend obviously.

Rational analysis model and seismic behaviour of tall bridge piers

Li, Jianzhong,Guan, Zhongguo,Liang, Zhiyao Techno-Press 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.51 No.1

This study focuses on seismic behaviour of tall piers characterized by high slender ratio. Two analysis models were developed based on elastic-plastic hinged beam element and elastic-plastic fiber beam element, respectively. The effect of the division density of elastic-plastic hinged beam element on seismic demand was discussed firstly to seek a rational analysis model for tall piers. Then structural seismic behaviour such as the formation of plastic hinges, the development of plastic zone, and the displacement at the top of the tall piers were investigated through incremental dynamic analysis. It showed that the seismic behaviour of a tall pier was quite different from that of a lower pier due to higher modes contributions. In a tall pier, an additional plastic zone may occur at the middle height of the pier with the increase of seismic excitation. Moreover, the maximum curvature reaction at the bottom section and maximum lateral displacement at the top turned out to be seriously out of phase for a tall pier due to the higher modes effect, and thus pushover analysis can not appropriately predict the local displacement capacity.

Creep Behavior of Unsaturated Reticulate Red Clay Under Matric Suction

Jianzhong Li,Yuanli Yang 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.2

In order to study unsaturated creep behaviors of reticulate red clay under matric suction, a series of isotropic creep tests with different matric suction level were carried out by using Geotechnical Digital Systems (GDS) unsaturated apparatus. Results indicate that creep strain caused by matric suction increases with the increasing of matric suction level and tends to certain stability over time. Based on the analyses of test results, a creep model for the unsaturated reticulate red clay under matric suction was established to predict the creep strain caused by matric suction. In the model, a new parameter M (matric suction level) was defined as a ratio of the matric suction to the net confining pressure, a hyperbolic function was adopted for the description of the strain-time relationship and an exponential function was employed for the strain-M relationship. Predicted results are in good agreement with the test results shows that the model can reasonably simulate the effects of matric suction on creep properties of unsaturated reticulate red clay.

Hybrid Color and Grayscale Images Encryption Scheme Based on Quaternion Hartley Transform and Logistic Map in Gyrator Domain

Jianzhong Li 한국광학회 2016 Current Optics and Photonics Vol.20 No.1

A hybrid color and grayscale images encryption scheme based on the quaternion Hartley transform(QHT), the two-dimensional (2D) logistic map, the double random phase encoding (DRPE) in gyratortransform (GT) domain and the three-step phase-shifting interferometry (PSI) is presented. First, we proposea new color image processing tool termed as the quaternion Hartley transform, and we develop an efficientmethod to calculate the QHT of a quaternion matrix. In the presented encryption scheme, the originalcolor and grayscale images are represented by quaternion algebra and processed holistically in a vectormanner using QHT. To enhance the security level, a 2D logistic map-based scrambling technique isdesigned to permute the complex amplitude, which is formed by the components of the QHT-transformedoriginal images. Subsequently, the scrambled data is encoded by the GT-based DRPE system. For theconvenience of storage and transmission, the resulting encrypted signal is recorded as the real-valuedinterferograms using three-step PSI. The parameters of the scrambling method, the GT orders and the tworandom phase masks form the keys for decryption of the secret images. Simulation results demonstratethat the proposed scheme has high security level and certain robustness against data loss, noise disturbanceand some attacks such as chosen plaintext attack.

Rational analysis model and seismic behaviour of tall bridge piers

Jianzhong Li,Zhongguo Guan,Zhiyao Liang 국제구조공학회 2014 Structural Engineering and Mechanics, An Int'l Jou Vol.51 No.1

This study focuses on seismic behaviour of tall piers characterized by high slender ratio. Two analysis models were developed based on elastic-plastic hinged beam element and elastic-plastic fiber beam element, respectively. The effect of the division density of elastic-plastic hinged beam element on seismicdemand was discussed firstly to seek a rational analysis model for tall piers. Then structural seismicbehaviour such as the formation of plastic hinges, the development of plastic zone, and the displacement at the top of the tall piers were investigated through incremental dynamic analysis. It showed that the seismic behaviour of a tall pier was quite different from that of a lower pier due to higher modes contributions. In a tall pier, an additional plastic zone may occur at the middle height of the pier with the increase of seismicexcitation. Moreover, the maximum curvature reaction at the bottom section and maximum lateral displacement at the top turned out to be seriously out of phase for a tall pier due to the higher modes effect, and thus pushover analysis can not appropriately predict the local displacement capacity.

The Dumb-bell Shaped Magnetostrictive/Piezoelectric Transducer

Jianzhong Li,Yumei Wen,Ping Li 한국자기학회 2011 Journal of Magnetics Vol.16 No.4

Traditional magnetostrictive/piezoelectric laminate composites are generally in the regular geometries such as rectangles or disks. To explore properties of the irregular geometry magnetostrictive/piezoelectric transducer in the fundamental resonant frequency, a step dumb-bell shaped Magnetoelectric (ME) transducer is presented in this study. Both analytical and experimental investigations are carried out for the dumb-bell shaped transducer in the fundamental frequency. Comparing with the traditional rectangular transducer, the theory shows the resonant frequency of dumb-bell shaped transducer is reduced 31%, and the experiment gives the result of that is 37% which is independent of dc magnetic fields. The ratio of magnetoelectric voltage coefficient (MEVC) between the dumb-bell shaped and rectangular shaped transducers in theory is 66% comparing with that of in experiment is varying from 140% to 33% when the dc field is increased from 0 Oe to 118 Oe.

Research on Suction Equilibrium Time of Unsaturated Reticulate Red Clay

Jianzhong Li,Hao Kangning,Peng Feng 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.2

Filter paper technique, humidity control technique and axis translation technique were used to study suction equilibrium time of unsaturated reticulate red clay. Test results show that: (a) suction equilibrium exists in both suction measurement or suction control using any technique in the tests; (b) suction equilibrium time of unsaturated reticulate red clay can be as short as several tens hour or several days for different suction measuring techniques, or long as several days or several tens day for different suction controlling techniques; (c) suction equilibrium time consumed in process of suction measurement is shorter than that of suction control using the same technique; (d) suction equilibrium time in measuring matric suction of unsaturated reticulate red clay using axis translation technique is shorter than that using filter paper technique; and (e) suction equilibrium time of drying process is much longer than that of wetting process, when suction is controlled using humidity control technique.