bluuebunny/crossref_metadata_2025 huggingface dataset:
A Novel System Strategy in CDMA Service Simulation and Air Interface Signaling Gathering
Authors: Wan Zheng , Shen Jian Hua , Jiao Liang Bao
Published: September 2012

Air interface signaling gathering and data analysis is the key technology in wireless network optimizations. Improved system architecture based on Smart Gathering Terminal (SGT), which performs the air interface signaling data collection and analysis is introduced in this paper. A signaling collection and processing strategy which based on cycle-queue and multithread data procession is proposed to increase the system efficiency and fulfill completeness requirement. Theoretical and experimental results show that the improved strategy can significantly increase data collection’s efficiency and ensure the signaling completeness.
The Design of Interface for Actuating Mechanism and CAN Bus Based on PC/104
Authors: Xu Bing , Xue Xue Dong , Wang Hong Li , Zhang Shu Ai
Published: September 2012

In order to link missile of actuating mechanism to CAN bus, an interface between actuating mechanism and CAN bus has been designed. It provides a method for the designing and realization of the hardware and software of interface. This interface has been used in reality. It proves that this design is feasible.
The Design and Implementation of Parallel Distributed Algorithm FIR Filter Based on FPGA
Authors: Zhang Bao Feng , Man De Hu , Zhu Jun Chao
Published: September 2012

The article proposed a new method for implementing linear phase FIR filter based on FPGA. For the key to implementing the FIR filter on FPGA—multiply-add operation, a parallel distributed algorithm was presented, which is based on LUT. The designed file was described with VHDL and realized on Altera’s field programmable gate array (FPGA), giving the design method. The experimental results indicated that the system can run stably at 120MHz or more, which can meet the requirements of signal processing for real-time.
Compression of Fault Data in Power System Based on Lifting Wavelet Transform
Authors: Wang Jun Fen , Liu Pei Yue , Ma Yan Ling , Xu Liang Yan
Published: September 2012

Along with the steady elevation of fault process monitoring level, the rapid increase of the fault recording data brought troubles to data transmission and storage. A new method of data compression combing lifting wavelet transform and Huffman coding was proposed in this paper. Data were converted from time-domain to frequency-domain by lifting integer wavelet transform. The high-frequency coefficients were then compressed by an improved threshold compression algorithm. Huffman coding was carried out with the processed data. Results of simulative experiments indicate that this method has a higher compression ratio when applied to fault recording data compression.
Simulation and Analysis of Stealth Fighter RCS in High-Frequency Band
Authors: Wang Kai , Cheng Li , Wang Xin Yu , Fu Cong Yi
Published: September 2012

The sky wave over-the-horizon radar (OTHR) works in high-frequency (HF) band, in which the stealth fighter RCS feature is largely different from that in microwave band. According to 3ds-Max model of F-22 fighter, RCS in HF band is computed by XFDTD software with different frequency, polarizations and angles. The simulation provides worthy preference on researching the ability of anti-stealth fighter of OTHR.
Full-Order Filters and Smoothers for Descriptor Systems with Delayed Measurements
Authors: Zhan Jiang Han , Ma Jing , Hao Jin , Ding Jian
Published: September 2012

This paper is concerned with the filtering problem for descriptor system with measurement delays. Using full-order transformation, the original descriptor system with delayed measurements is transferred to the normal system with delayed state and delayed measurements. Based on the projection theory, the filter and smoother of the normal system are derived. Then, the full-order filter and smoother of the original descriptor system are given. The proposed estimators avoid the high-dimensional computation from state augmentation. Simulation research verifies the effectiveness of the proposed algorithm.
Design and Experimental Study of Deposition Temperature Control System in Ultra-High Vacuum
Authors: Yan Zhi Dan , Sun Li Dong , Hu Chun Guang , Hu Xiao Tang , Zeppenfeld Peter
Published: September 2012

Deposition temperature is a key factor influencing the growth morphology of thin-films, aiming at this phenomenon, a precise control system of deposition temperature in ultra-high vacuum is developed in the paper. It can realize accurate temperature control in a range of 150K to 450K during experiment by combination of resistance heating up and liquid helium cooling down strategies, which is benefit to further understand the temperature-depended mechanism of organic molecule thin-film growth. Besides, it is experimentally studied that the growth morphology of p-6p molecules on a mica substrate is closely related to the substrate deposition temperature, indicating that the length of p-6p nano-fibers is proportional to the deposition temperature, while their distribution density is inversely proportional to the temperature.
Monte Carlo Model of Optomechanical Tolerance for Lens Assembly
Authors: Lin Qin Hong , Da Zheng Shang
Published: September 2012

Research on the opto-mechanical tolerance analysis for lens optical system is presented. Take a traditional "drop-in" assembly for example. How fabrication tolerances transfer to tolerances of optical elements is analysed. Finally, Monte-Carlo model for opto-mechanical tolerances is proposed, which considers both the fabrication and assembly process.
Applications of ARM-Based Remote Monitoring System for Large Scale Poultry Farm
Authors: Lu Yu Qing
Published: September 2012

Specific Pathogen Free (SPF) chicken are feuded in barrier system or isolation imple- ments, having good growth and reproductive performance. Through integration with advanced risc machines (ARM) board, an optimized Chicken-Disease Expert System is improved. This paper presents the design and implement of GPRS remote terminal based on ARM MPU (Micro Processor Unit) in SPF chicken farm. At the same time, extensibilities of this software structure are described and sufficiently considered in the system design stage. Therefore, some common defects of similar poultry feeding systems are overcome in implementation. The results show the GPRS remote client can provide a flexible user interface and will play an important role in safety of poultry farms.
The Implementation of Instrumentation Systems of Fire Truck Simulator Based on PLC
Authors: Wang Li Wen , Chen Xi , Jia Li Shan
Published: September 2012

The structures of the instrumentation systems of the airport fire truck simulator uses a distributed control of the PC and PLC, combined with the advanced technology of the widespread use of the stepper motor control of the instrument. And combined stability, adaptability and strong anti-jamming capability of PLC and the stepper motor’s positioning accuracy, ease of control, and high reliability. It is used the unique high-speed pulse output function of PLC to realize the real time and accurate control of stepper motor. It is also use the serial port class SerialPort in VC + + 6.0 programming environment on Serial communication side. The experiment proved that the system design is reasonable, and the instrument can be a smooth, quiet and accurate operation.
Generalized Block Triangular Preconditioner for Saddle Point Systems
Authors: Cheng Shao Hua , Zhang Li Tao
Published: September 2012

In this paper, based on the preconditioner for saddle point systems in Benzi and Liu [M. Benzi, J. Liu, Block preconditioning for saddle point systems with indefinite (1,1) block, International Journal of Computer Mathematics, 84(8) (2007) 1117-1129], we present the generalized block preconditioner for generalized saddle point systems, which uses some more parameters and is a generalization of Benzi and Liu's block preconditioner. Moreover, spectral properties of our generalized block triangular preconditioner are given.
Research on the Three-Dimensional Velocity Field Splitting Measurement Method of Cavitations-Impinging Stream Reactor
Authors: Li Qin , Li Fu Bao , Li Zhong Ke , Wang De Xi
Published: September 2012

In the Particle image velocimetry (PIV) measurement system, using the basic measurement principles of three-dimensional space position and splitting method, it, using a CCD camera, achieved the measurement to a space position. Light emitting diodes flash twice and image in the same CCD camera and space vector can be obtained directly by the image processing, and then three-dimensional velocity field can be obtained.
Study of Electromagnetic Scattering Characteristics from Typical Land Surface with Integral Equation Method
Authors: Zhang Yuan Yuan , Wu Zhen Sen , Li Ya Qing , Zhang Han Lu
Published: September 2012

Based on the equivalent dielectric model, the permittivity of the soil and simple plants which are assumed to satisfy exponential rough surface model is calculated. The electromagnetic scattering coefficients for the two types of rough surfaces are investigated by the Integral Equation Method (IEM) with the changing dielectric constant. The detailed analysis and discussions are made. And the results obtained are in good agreement with the experimental results.
Role of Molecular Alignment Distribution in High Harmonic Generation
Authors: Huang Bang Lei , Wu Jia Jun , Wei Peng Fei , Huang Xiao Hong
Published: September 2012

The role of the molecular alignment distribution with high harmonic generation (HHG) in aligned CO2 molecules is investigated and discussed in this letter. We first present the molecular field-free alignment and the polar plot of the weighted alignment distribution, and then also give the angular distribution of the molecular HHG. At last, we theoretically and experimentally demonstrate the alignment dependence for the molecular HHG. These results systematically verify the role of the molecular alignment distribution in the HHG process, which is useful for investigating the molecular dynamics in practical application.
A Novel Multipriority Reservation Protocols for Optical Fiber Network
Authors: Zhang Yu
Published: September 2012

POF is a very attractive candidate for transmission media in access network based on OCDMA technology being its low-cost, larger core diameter, huge bandwidth, more flexible, higher endurable to repeated bending, easier to install and maintain. OCDMA scheme is employed not only efficiently exploit the huge bandwidth potential of POF but also simplify the control logic. To resolve the problem a novel protocol also is proposed in this paper. The number of data channels does not restrict the number of units in the network and real time traffic always is serviced before non-real time traffic. The performance of the proposed multipriority control protocol using various system parameters has been investigated by numerical analysis and simulation experiments. It is showed that the control protocol is valid and efficient.
An Embedded Multimedia Player on S3C6410 Platform
Authors: Liu Yu Hong , Wang Shui
Published: September 2012

Designs and implements an embedded multimedia player on Samsung S3C6410 platform; this player can support both hardware and software decoding using its built-in decoding interfaces and FFmpeg, which can decode multiple content formats including MPEG4, H.263, H.264 and VC1. Also, a novel model is proposed to gain better synchronization effect. The system architecture and results of preliminary performance experiments are presented.
The Doppler Radar Bomb Chamber Volume Speed Measurement System Research Based on LabView
Authors: Song Nuan , Jiao Yang , Song Ya Ji , Liu Chun Hui
Published: September 2012

This article in view of the firing range and speed of ballistic test parameters, follow the "virtual instrument" thought to design a multi-function weapon test system, establishing a uniform platform development and complete Doppler radar speed module, meet a variety of ballistic speed needs. In the system, we realize intelligent control, real time collection of signal in time and frequency domain, result display at the same time and data analyze, Based on hardware realize, system realize testing of chamber volume.
The Application of Frequency Response Analysis in Online Testing System of Transformer
Authors: Zhou Wei , Liu Bao Bin
Published: September 2012

Online testing system based on frequency response analysis is proposed for the deformation of transformer winding. The structure of testing system, the selection of sweep sequence and computer diagram of data acquisition system are developed in the course of design. In the process of analysis, the concept of correlation coefficient is introduced to judge the relationship between the deformation extent and correlation coefficient. With the proposed method, the location of deformation can be determined. The testing curves demonstrate the effectiveness of the presented system.
Transmission and Receiver Double Smoothing for Multitarget Localization in MIMO Radar
Authors: Li Hong Bing , Wang Yan , Gong Jian
Published: September 2012

The received echo signals from different targets are considered as coherent in the MIMO radar. In order to improve the performance of direction estimation of multiple targets in lower SNR for MIMO radar, a new algorithm termed Transmission and Receiver Double Smoothing (TRDS) is proposed. Compared with the Transmission Diversity Smoothing algorithm, TRDS can deal with more targets in lower SNR with higher resolution. The theoretical analysis and simulation results show the proposed method is effective.
Miniature UWB Filter Using Three-Quarters Wavelength Resonator with Direct-Connected Feed Method
Authors: Peng Cai
Published: September 2012

A miniature ultra-wideband (UWB) bandpass filter using three-quarters wavelength resonators is presented in this paper. Direct-connected feed method is employed between the input/output ports and the resonators in order to overcome the shortcomings due to the gap-coupled feed method and produce two transmission zeros in the lower and upper stopbands. On the other hand, two quarter-wavelength matching transmission lines are introduced to the input/output ports to improve the reflection loss characteristic in the passband of the filter. In addition, the resonators are folded to be open ring structures, which are more miniaturized than the conventional linear structure. As a consequence, the filter is compact in size and exhibits good performance. The filter is successfully realized in theory and verified by full wave EM simulation, and simulated frequency response results show that the fabricated filter has an insertion loss of better than 1dB in the passband and two rejections of greater than 25dB in most of the stopbands.
Optimal Design of CCD Driving Signal Based on FLEX 10K
Authors: He Zhi Kuan , Wu Song Bo , Zhang Yu Gui
Published: September 2012

In this paper, an optimal design method for a CCD driving signal is proposed. Strict phase alignment of CCD driving signals is achieved. Through the analysis of FLEX 10K internal resources, the CCD driving pin voltage overshoots are eliminated on the basis of meeting the phase relationship. The experimental results show that the requirements for the phase of the CCD driving signals are satisfied, and the voltages on CCD pins become stabile. Therefore, CCD can be protected from damage.
Thermal Conductivity of SOI LDMOS Device
Authors: Xiong Yan , Lai Yu Shu
Published: September 2012

In this paper, the thermal conductivity of lateral double diffused metal oxide semiconductor (LDMOS) was studied. In order to optimize their properties, the LDMOS device based on the lower surface of field (RESURF) theory join the second field plate technology. Power device self-heating effect will affect the carrier mobility, making its negative resistance effect in IV characteristic curve under the high-power condition. As the thermal conductivity of SiO2 is low, the self-heating effect of SOI device is more obvious. The simulation using Silvaco -TCAD software for different buried oxide (BOX) with different SOI layer thickness accordingly show that the thicker SOI layer and the thinner buried oxide layer, the smaller the self-heating effect.
The Structural Design of Combined Absorber Composed by MPP and Multi-Layer Porous Material Based on VA One
Authors: Duan Xiu Hua , Wang Huan Qin , Sun Wen Juan , Kong De Yi , Zhao Zhan
Published: September 2012

Some experiments found that the low-frequncy sound absorption performance can be improved by inserting MPP into the multi-layer porous materials, but the theory modeling of this MPP-multi-layer porous combined absorber is too difficult to provide the guidance. Therefore, a new method is proposed in this paper, according to Atalla’s theory, the MPP can be treated as a rigid porous layer in this composite absorber, then the acoustic software (such as VA One) usually for dealing with multi-layer porous absorber can be chosen to its optimal design. Based on this method, a two-layer porous absorber is designed using the Foam Module of VA One, and the influence of different insert location of MPP in the two-layer porous absorber is analyzed, which shows the existence of optimum location. Moreover, the sound absorption of different MPP structure at the optimum location is also discussed which shows inserting the wider-band MPP structure is better.
Integrated Piezoelectrics for Smart Microsystems - A Teamwork of Substrate and Piezo
Authors: Gebhardt Sylvia , Ernst Dörthe , Bramlage Bernhard , Flössel Markus , Schönecker Andreas
Published: September 2012

Microelectronic substrates like silicon, alumina and LTCC (Low Temperature Cofired Ceramics) allow for high robustness and reliability, 3D packaging (electrical connection, channels, cavities and membranes) as well as integration and application of electronic components whereas piezoceramic materials offer sensor and actuator operations. To combine the advantages of both, integrated solutions are of great interest. This paper deals with two approaches of monolithic integration, (i) screen printing of piezoceramic thick films on microelectronic substrates and subsequent post firing and (ii) integration of pre-fired piezoceramic components into green LTCC multilayer packages and subsequent sintering. Functionality of smart microsystems not only depends on the outer design and construction but to a great part on interaction of substrate and piezoceramic material properties. A thorough choice of materials as well as the understanding and prevention of chemical reactions are necessary to build effective systems.
Tristriazolotriazines with π-Conjugated Segments: Star-Shaped Fluorophors and Discotic Liquid Crystals
Authors: Glang Stefan , Borchmann Dorothee , Rieth Thorsten , Detert Heiner
Published: September 2012

C3-symmetrical tristriazolotriazines substituted with phenylene rings carrying lateral flexible alkoxy side chains were prepared via condensation/ring transformation of cyanuric chloride and tetrazoles. These star-shaped, planar compounds can form broad thermotropic mesophases. Due to the extensive π-conjugation, these compounds are highly emissive and the octupolar donor-acceptor electronic structure results in non-linear optical properties like solvatochromism. Brønstedt acids provoke halochromism of the absorption and of the fluorescence.
Thermotropic Materials for Adaptive Solar Control
Authors: Ruhmann Ralf , Seeboth Arno , Muehling Olaf , Loetzsch Detlef
Published: September 2012

Thermotropic materials offer an immense potential in adaptive solar control. They combine specific optical properties like absorbance and reflection, and high stability against solar radiation and heat with technology compatible processing capacities. Therefore, they represent perfect energy efficient materials. In detail, polymer blends, polymer-based hydrogels, casting resins, and thermoplastic films with a reversible temperature-dependent switching behavior have been investigated. Here a comparative evaluation of the different concepts with a view to their application in adaptive solar control is presented. Own current results exploit the well-known phase change materials and describe its use for adaptive solar control with extruded films or highly stable casting resins with thermotropic properties. Therewith, the status has changed from diffuse sunblind systems to intrinsic solar energy reflecting materials and a first smart window system based on phase change materials has now commercialized [1]. In summary: It is amazing that the solar energy itself is used as a promoter against solar heat.
Poly(vinylidene fluoride) Interleaves for Multifunctional Fiber Reinforced Composites
Authors: Ehlert Gregory J. , Tang Hai Xiong , Meeks Natalie R. , Sodano Henry A.
Published: September 2012

The integration of energy storage into structural multifunctional materials has found use in a wide variety of applications, such as future air and ground vehicles. However, the present realization of these materials cannot be used to increase the structural properties thus limiting its future use in these applications. Here, we developed a novel multifunctional composite material using polyvinylidene fluoride (PVDF) interleaves in carbon fiber composites. The carbon fibers function as both the structural reinforcement as well as the electrodes for the dielectric polymer. It has shown that energy storage functionality can be added into the composites with no reduction in the short beam shear strength. Currently, the breakdown strength is low due to challenges in the processing of the composites and the potential for regions of reduced thickness during pressing. In future research, the manufacturing process of the composites will be investigated to improve the breakdown strength in order to obtain high energy density in addition to preserving the outstanding mechanical properties. This new multifunctional material will open a door to the development of advanced structures that distribute energy storage throughout the composite thus eliminating their current ad hoc implementation.
Highly Porous Polymeric Foam of Maleimide-Termiated Poly(arylene ether sulfone) Oligomers via High Internal Phase Emulsions
Authors: Thanamongkollit Khemchart , Pakeyangkoon Pornsri , Malakul Pomthong , Nithitanakul Manit
Published: September 2012

PolyHIPEs are highly porous polymeric form, prepared through emulsion templating by polymerizing the continuous phase of high internal phase emulsions (HIPEs). A maleimide-terminated aryl ether sulfone oligomer (MAPES) was copolymerized with divinylbenzene (DVB) in the continuous phase, using a mixed surfactants system (sorbitan monooleate (Span80), cetyltrimethylammonium bromide (CTAB), dodecylbenzenesulfonic acid sodium salt (DDBSS)), and peroxide initiator, to improve CO2 adsorption and the mechanical properties of obtained materials. PolyHIPEs were prepared by two different ratios of mixed surfactants; (SPAN80, DDBSS, and CTAB; 6.3, 0.4, and 0.3 wt%, which was denoted as 7s) and (SPAN80, DDBSS, and CTAB; 11.3, 0.4, and 0.3 wt%, which was denoted as 12s). 0, 2.5, 5, 10, 20, and 30 wt% of maleimide-terminated aryl ether sulfone oligomer were copolymerized with DVB. All PolyHIPE nanocomposites foam were characterized for phase morphology, thermal behavior, surface area, mechanical properties and adsorption of CO2 by using SEM, TG-DTA, N2 adsorption-desorption, LLOYD universal testing machine and CO2 adsorption unit, respectively. The obtained PolyHIPEs showed an open cell and a secondary pore structure with surface areas of approximately 400m2/g. CO¬2 adsorption tests were characterized by pilot gasification unit and the obtained materials showed higher adsorption than neat poly(DVB) without MAPES. Compressive modulus test of the materials showed a higher modulus than for poly(DVB) PolyHIPEs.
Surface Modification of High Internal Phase Emulsion Foam as a Scaffold for Tissue Engineering Application via Atmospheric Pressure Plasma Treatment
Authors: Pakeyangkoon Pornsri , Magaraphan Rathanawan , Malakul Pomthong , Nithitanakul Manit
Published: September 2012

Atmospheric pressure plasma treatment was used to improve hydrophilic properties and scaffold/cell interaction of poly(S/EGDMA)polyHIPE highly porous foam, prepared from poly(styrene/ethylene glycol dimethacrylate) using high internal phase emulsion technique. With our synthesis procedure and surface treatment, this bioactive material, featuring highly porous structure and good mechanical strength, can be applied as a scaffold for tissue engineering applications. The treatment time and external plasma parameters were investigated in regards to the polyHIPE foam surface’s appropriate for fibroblast implantation. The changes in surface properties were characterized by contact angle measurement, showing that the exposure to air-plasma induced polyHIPE foam with hydrophilic surfaces, as observed by a decrease in contact angle degree. Enhancement of the interaction between the polyHIPE foam and the L929 fibroblast-like cells would imply the hydrophilic improvement of the polyHIPE foam surface due to the polar-like property of the biofluid cell medium.
Influence of Hydrochloric Acid Concentrations on the Formation of AgCl-Doped Iron Oxide-Silica Coreshell Structures
Authors: Mahmed Norsuria , Heczko Oleg , Hannula Simo Pekka
Published: September 2012

Silver chloride (AgCl) nanoparticles with the average size of about 45 nm have successfully been doped onto the iron oxide-silica coreshell surfaces by a simple room temperature wet chemistry method under ambient atmosphere. The Stöber process has been used to make the coreshell structure, followed by adsorption of Ag+ species on silica surface prior to the addition of hydrochloric acid (HCl) and polyvinylpyrrolidone (PVP). The concentration of HCl acid that was used to induce the growth of AgCl particles was varied from 0.12 mM to 12x103 mM of concentrations. Results showed that at a very high concentration of HCl (12x103 mM), large AgCl agglomerates (0.3-0.6 microns) with irregular cubic-like morphology were obtained while at a very low, 12 mM HCl concentration, 30-50nm AgCl particles having a uniform cubic morphology were observed. Concentrations below 12 mM result in irregular and nearly spherical morphology of AgCl particles with a smaller size (28-60 nm). UV-Vis absorption of the composite materials showed absorption in the visible wavelength indicating that Ag nanoclusters might coexist together with AgCl particles.
Magnetoelectric Properties in Nickel Ferrite – Niobate Relaxor Bulk Composites
Authors: Guzdek Piotr
Published: September 2012

Magnetoelectric effect in multiferroic materials is widely studied for its fundamental interest and practical applications. The magnetoelectric effect observed for single phase materials like Cr2O3, BiFeO3, Pb(Fe0.5Nb0.5)O3 is usually small. A much larger effect can be obtained in composites consisting of magnetostrictive and piezoelectric phases. This paper investigates the magnetostrictive and magnetoelectric properties of nickel ferrite Ni0.3Zn0.62Cu0.08Fe2O4 - relaxor Pb(Fe0.5Nb0.5)O3 bulk composites. The magnetic properties of composites shows a dependence typical of such composite materials, i.e. it consists of a dominating signal from ferrimagnetic phase (ferrite) and a weak signal from paramagnetic (antiferromagnetic) phase (relaxors). Magnetoelectric effect at room temperature was investigated as a function of static magnetic field (300-7200 Oe) and frequency (10 Hz-10 kHz) of sinusoidal modulation magnetic field. The magnetoelectric effect increase slightly before reaching a maximum at HDC = 750 Oe and then decrease. The magnetoelectric coefficient increases continuously as frequency is raised, although this increase is less pronounced in the 1-10 kHz range.
Magnetic Properties of the Bi7Fe3Ti3O21 Aurivillius Phase Doped with Samarium
Authors: Bućko Mirosław M. , Polnar Joanna , Lis Jerzy , Przewoźnik Janusz , Gąska Karolina , Kapusta Czesław
Published: September 2012

Bismuth layer-structured compounds in the Bi-Ti-Fe-O system known as Aurivillius phases are single phase multiferroics. It was stated that substitution of some rare earth elements for bismuth ions in such structure can modified its magnetic properties. Powders of Bi7Fe3Ti3O21 and Bi6.3Sm0.7Fe3Ti3O21 were prepared by co-precipitation – calcination method and then were sintered to dense polycrystalline materials. Low field DC susceptibility was measured in the zero field cooled (ZFC) and field cooled (FC) modes at 10÷350 K. For selected temperatures magnetisation curves and hysteresis loops were also measured. The FC and ZFC curves of both samples diverge at temperatures below 250 K indicating a spin glass-like behaviour. The compound with samarium exhibits magnetic hysteresis already at room temperature with the coercive field increasing to 870 Oe at 10 K. The low temperature hysteresis loops of the samarium containing compound are shift with respect to zero field which can be attributed to a magneto-electrical coupling of the samarium sublattice "exchange biased" by the iron one, which orders anti-ferromagnetically at a higher temperature than the samarium sublattice.
Reflection of Electromagnetic Waves from Multiferroic TbMnO3
Authors: Bychkov Igor V. , Kuzmin Dmitry A. , Lamekhov Sergei J. , Butko Leonid N. , Shavrov Vladimir G.
Published: September 2012

Reflection coefficient of electromagnetic waves from TbMnO3 surface with sinusoidal structure and permittivity are examined. Model of material with spin, elastic and electromagnetic interactions used. Resonance kind of reflection coefficient and of permittivity was shown. Found spectrum and reasoned existing of band-gaps in coefficient of reflection.
Method of CRLH Antenna Impedance Measurement by Means of On-Wafer Characterization Equipment
Authors: Sajin Gheorghe Ioan , Mocanu Iulia Andreea , Voicu Marius Andrei
Published: September 2012

The paper deals with a measurement method of the input impedance in the radiating section of a coplanar waveguide (CPW) Composite Right / Left-Handed (CRLH) antenna. In this respect were used the technical facilities offered by an on-wafer measurement equipment contacting the antenna feeding line. With appropriate formulas derived from the theory of the transmission lines, the resistive Rs and the reactive Xs parts of the CRLH radiating structure impedance Zs = Rs + jXs were found. The results for three antenna samples were: Zs1 (Ω) = 48.5326 - j×16.9639, Zs2 (Ω) = 48.6053 - j×16.8143 and Zs3 (Ω) = 48.1786 - j×16.3707. As it is normal, the reactive parts of the measured impedances are negative due to the CRLH line construction with series interdigital capacitors inducing left hand behavior.
Breakdown of the Quantum Hall Regime in a ‘Confined’ Graphene
Authors: Morita Yoshifumi
Published: September 2012

Our focus is on the graphene under a magnetic field with Landau levels i.e. quantum Hall regime where a ‘confining potential’ is imposed by a finite electric field. In our theory, the graphene is modelled by a conventional fermion on a honeycomb lattice and the finite electric field is by a static potential. We reveal the fate/breakdown of the quantum Hall regime. A possible candidate of this kind of system is a grapheneQuantumDot, which we also discussed in the light of our theory.
Cobalt Doped ZnO Nanorods Fabricated by Chemical Bath Deposition Technique
Authors: Hari Parameswar , Seay Jared , Farmer Kevin , Roberts Ken
Published: September 2012

ZnO nanorods are currently studied for variety optoelectronic applications. Typically, thin film and bulk ZnO show a strong light absorption in the ultra violet (UV) range. For devices that operate in the visible and infrared range such as optoelectronic sensors and photovoltaic cells, it is necessary to modify the absorption profile from UV to higher wavelengths in the visible region. In this study we investigate optical absorption of ZnO nanorods doped with cobalt using a modified chemical bath deposition technique. The light absorption properties of Cobalt doped ZnO nanorods were studied using Photoluminescence (PL) and Raman Spectroscopy. For doping of Cobalt ranging from 3 to 10 percentage of the total weight, the PL intensity shows a suppression of the prominent UV peak at 383 nm with increase in doping concentration. This reduction in PL intensity at 383 nm is accompanied by an increase in the PL intensity at 429 nm and 469 nm. We will discuss details of ZnO-Cobalt structures using Raman spectroscopy on cobalt doped ZnO nanorod samples of 1 -20% doping concentration.
The Synthesis of In-Se by Vapor Transport Method
Authors: Takano Naoki , Kohri Hitoshi , Yagasaki Takayoshi
Published: September 2012

The α and β phases of In2Se3 are attractive thermophotovolβtaic (TPV) materials. For example, they have a direct transition and an optimal bandgap for TPV systems. We investigated about the influence of the growth conditions on the crystal forms of In-Se prepared by vapor transport. Firstly, only bulk In2Se3 was encapsulated in a quartz ampoule and crystals were grown by vapor transport. Hollow hexagonal cylinders that were approximately 10 μm in diagonal dimension were obtained. They were identified as a mixed phase of In2Se3 by XRD. Secondly, the deposition surface configuration was varied by using an ampoule with a smaller internal diameter and a silicon oxide substrate. Hollow hexagonal cylinders that were approximately 20 μm in diagonal dimension were obtained on the inner wall of the ampoule with a smaller internal diameter. Solid hexagonal crystals of approximately 10 μm in diagonal dimension grew perpendicular to the silicon oxide substrate, whereas hollow hexagonal cylinders grew on the inner wall of the ampoule. Finally, the surface energy of the deposition surface was varied for silicon substrate. Nanoparticles with diameters of approximately 50 nm were sparsely deposited on the textured silicon surface.
Hybrid Photovoltaic-Piezoelectric Flexible Device for Energy Harvesting from Nature
Authors: Vatansever D. , Hadimani R.L. , Shah Tahir , Siores E.
Published: September 2012

Photovoltaic energy can be expensive if the solar radiation in a particular region is not abundant. When the solar radiation is scarce in a region, there is presence of winds and rainfall. If flexible solar cells are coupled with flexible piezoelectric films then the hybrid structure can generate energy from solar radiation, wind and rainfall. Hybrid piezoelectric-photovoltaic devices have been developed which are capable of generating electricity from solar as well as wind and rain energy. This work focuses on non-transparent hybrid structure which contains copper and aluminium electrodes and eliminates the used of costly indium tin oxide (ITO).These hybrid films are made by depositing organic photovoltaic cell based on P3HT and PCBM on a commercial PVDF film. The hybrid piezoelectric-photovoltaic film was first tested under a solar simulator with 1.5 AM filter at one sun solar intensity. The film produced an open circuit voltage, Voc of 0.43V and a short circuit current density, Isc of 4.48mA/cm2. It was then subjected to a turbulent wind speed of 10m/sec (36km/hour) in a custom built wind tunnel. A peak voltage of 52V was generated by the PVDF substrate due to the oscillations created by the wind. Peak power was also measured using a variable resistor and was recorded to be 85 µW. In order to check if the film was not damaged when it was subjected to the turbulent wind speed, the film was again tested under the solar simulator and did not show any changes in its open circuit voltage or short circuit current.
Multiple Shape-Memory Behavior of Polyethylene/Polycyclooctene Blends Cross-Linked by Electron Irradiation
Authors: Radusch Hans Joachim , Kolesov Igor , Gohs Uwe , Heinrich Gert
Published: September 2012

Comparative investigation of the thermo-induced unconstrained shape-memory (SM) recovery of a multi-phase semi-crystalline covalent network was performed using cross-linked polyolefin based blends of linear high density polyethylene (HDPE) and/or short-chain branched ethylene octen copolymers (EOC) as well as polycyclooctene (polyoctenamer, TOR). Different phase morphologies of the blends were generated by variation of blend composition and different pathways for sample preparation: Melt mixing of blends, compression molding of films, slowly cooling or quenching of films and subsequent cross-linking by electron irradiation at room temperature. Partly well developed triple- and quadruple SM behavior after one-step programming process was demonstrated for binary and ternary HDPE/EOC/TOR blends, which exhibit a morphology with segregated phases, where the matrix has the lower melting and correspondingly switching temperature (Tm and Tsw) in comparison to the disperse phases. These blends show pronounced steps of SM strain recovery and storage modulus as well as distinct DSC melting peaks. The peaks of SM recovery rate are located in the Tm range of the blend phases. The quenching procedure resulted in a better phase separation at nano-level and correspondingly in a more pronounced triple-shape behavior of the blends. All HDPE/EOC/TOR blends showed high values of strain fixing and strain recovery ratios of 95 to 99 %.
Modeling of Shape-Memory Recovery in Crosslinked Semicrystalline Polymers
Authors: Kolesov Igor , Dolynchuk Oleksandr , Radusch Hans Joachim
Published: September 2012

In present work a new theoretical approach based on the modified three-element Eyring-Halsey mechanical model was used for the derivation of an equation, which describes the thermally-induced recovery of preloaded covalently crosslinked polymer. This approach takes into account the influence of crystallizable polymer network as well as of entangled slipped molecular chains. Modeling of the temperature dependences of shape-memory (SM) recovery strain and SM recovery rate detected at constant heating rate has been performed for three types of polyethylene with sufficiently different crystallinity and crosslink density at programming strain of 100%. The results of modeling agree well with the experimental data. The values of material parameters determined by fitting correspond satisfactorily to the estimations existing in literature. It is shown that the contribution of the entangled slipped molecules to the total stored SM strain increases with increasing degree of branching and crosslink density. The physical sense of main fitting parameters and their dependences on the material constants such as crystallinity are discussed.
Multilayer Ceramic Capacitors Based on the PMN-PT-PFN Solid Solution
Authors: Skulski Ryszard , Wawrzała Paweł , Bochenek Dariusz , Kulawik Jan , Szwagierczak Dorota , Niemiec Przemysław
Published: September 2012

We present the technology of obtaining and the main properties of multilayered ceramic capacitors (MLCC) based on the PMN-PT-PFN solid solution. PMN-PT-PFN is the abbreviation of the material with general formula (1-y)[(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3]-yPb(Fe1/2Nb1/2)O3. In our work the investigated material was PMN-PT-PFN with x=0.25, y=0.1 i.e. 0.9(0.75PMN-0.25PT)-0.1PFN. The powder of 0.9(0.75PMN-0.25PT)-0.1PFN has been obtained in three steps. In first step we obtained MgNb2O6. In second step FeNbO4 was obtained. In final third step the 0.9(0.75PMN-0.25PT)-0.1PFN was obtained from mixed powders MgNb2O6, FeNbO4, PbO and TiO2. Thick film pastes for obtaining MLCC were prepared by mixing of PMN-PT-PFN powder with organic vehicle and firing in furnace in the temperature range up to 1050°C. Platinum paste has been used as electrodes. The thickness of single layer was about 45 µm (including electrodes). For obtained MLCC XRD investigations were performed as well as investigations of microstructure, EDS and main dielectric properties.
Hydrogel Sensors for Process Monitoring
Authors: Windisch Markus , Junghans Thomas
Published: September 2012

For the direct measurement of chemical concentrations of substances in process liquids, sensors need to be fast and reliable. We investigated the usability of hydrogels as sensitive coating materials for piezo-electric thickness shear mode resonators. Hydrogels are cross-linked polymer networks that show well-defined shifts of their degree of swelling upon changes of environmental parameters such as ionic concentrations, concentrations of organic solvents or temperature. These changes of gel properties are then transferred into an electrical signal. The novel sensor solution exhibits response times of only few seconds and matches the reliability of innovative process measuring technology. A method for its application specific adaption is presented. It is based on optimizing the interrelation of the sensor structure, the manufacturing technology for the hydrogel layer, and the processing of the measured data. The performance of the method is illustrated with the example of a PVA/PAAhydrogel coated sensor which monitors the concentration of a cleaner used in surface technology. The developed measurement device for this application was approved with a measurement error of less than 5 %.
From Dual-Shape/Temperature Memory Effect to Triple-Shape Memory Effect in NiTi Shape Memory Alloys
Authors: Tang Cheng , Huang Wei Min , Wang Chang Chun
Published: September 2012

Triple-shape memory effect (SME), i.e., to recover the original shape through one intermediate shape upon heating, has been demonstrated as an intrinsic feature of thermo-responsive shape memory polymers (SMPs) after being uniformly programmed, but seemingly has yet been achieved in shape memory alloys (SMAs). In this paper, we study two programming approaches, in which the deformation is uniform throughout the whole sample length without involving any permanent change in material properties at all, to realize the triple-SME in NiTi SMAs. We show that the triple-SME can be tailored to meet the temperature/strain requirements. With this technique, now we are able to achieve step-by-step motion control in SMAs.
An Open-Loop Control Approach for Magnetic Shape Memory Actuators Considering Temperature Variations
Authors: Schlüter Kathrin , Riccardi Leonardo , Raatz Annika
Published: September 2012

Magnetic shape memory alloys (MSMA) offer remarkable potentials for actuation purposes because of a large achievable strain and a short response time. But, apart from these advantages, MSMA show a hysteretic behavior between the input and output quantities. Hysteretic phenomena represent an important challenge for the design of control systems for MSMA-based actuators. Furthermore, this hysteretic behavior is sensitive to temperature variations, a situation that arises in many applications. To face the problem of increasing/decreasing temperature during operation, an open-loop control approach considering temperature variations is presented in this paper. For this purpose, an actuator prototype is characterized with particular emphasis on temperature influence concerning the input-output behavior. The presence of a time-varying nonlinearity is addressed by means of a set of hysteresis models and relative compensators to improve the positioning performance of the actuator system. Subsequently, the obtained models are integrated in the control loop and tested experimentally. Finally, the results achieved with the introduced control concept are presented.
Studies on Internal Friction of a High Temperature Cu-Al-Mn-Zn Shape Memory Alloy
Authors: Sampath Vedamanickam , Chandran Prathap
Published: September 2012

Materials with high damping capacity for quelling noise and vibration in engineering structures have drawn increasing attention in recent times. Among the different materials that have been attempted so far, shape memory alloys (SMAs) have shown much promise since they exhibit much higher damping due to the occurrence of a thermoelastic martensitic transformation in them. Among the SMAs it is copper-based SMAs that have proved more attractive compared to Ni-Ti SMAs because of their lower cost, higher damping and better machining characteristics. In the present work, therefore, the damping properties of a Cu-Al-Mn-Zn alloy, a potential high damping material for high temperature turbomachinery rotor blades, are investigated. The internal friction was studied using a dynamic mechanical analyzer over a range of temperatures (25-300°C), frequencies (0.5-10Hz) and strain amplitudes (5×10-6 and 10-4). The analysis of the results reveals that the damping properties are more sensitive to variation in frequency and strain amplitude, pointing to the suitability of the material for the intended application. The results are presented and discussed in the paper.
Composition Dependence of Compatibility in Self-Accommodation Microstructure of β-Titanium Shape Memory Alloy
Authors: Teramoto Takeshi , Tahara Masaki , Inamura Tomonari , Hosoda Hideki , Miyazaki Shuichi
Published: September 2012

Composition dependence of the compatibility condition at junction plane (JP) (interface between habit plane variants (HV)) was evaluated by geometrically non-linear theory of martensite in Ti-Nb-Al shape memory alloys that have β (cubic) to α” (C-orthorhombic) martensitic transformation. The kinematic compatibility (KC) condition requires non-zero rotation of HV to form compatible JP; the angle of this rotation is termed θ. This means that the invariant habit plane (HP) and the compatible JP are not formed simultaneously. It turned out that twelve types of θ exist depending on the pair of HV. Composition dependence of each type of θ was systematically investigated. The previous results of transmission electron microscopy observations were also discussed in terms of the present results.
Transformation Behavior of Shape Memory Alloys in Multiaxial Stress State
Authors: Yamamoto Takaei , Suzuki Akihiko , Cho Hiroki , Sakuma Toshio
Published: September 2012

The transformation behavior of shape memory alloys is simulated for complex loadings of stress, strain and temperature. Calculations are made by using the “Accommodation Model” which is a constitutive model for shape memory alloys considering the accommodation behavior of the transformation strain. Calculated results are presented for the transformation behavior in the axial and shear stress state. These results are compared with those obtained by the experiment where tube specimens of the Ti-Ni shape memory alloy are subjected to the axial and torsion loading. The proposed constitutive model can predict the transformation behavior including the plastic strain effect of polycrystalline Ti-Ni shape memory alloys under non-proportional multiaxial loading condition.
Design and Simulation of a Magnetic Shape Memory (MSM) Alloy Energy Harvester
Authors: Niskanen Antti J. , Laitinen Ilkka
Published: September 2012

We present the simulation and development of a vibration energy harvester based on an active element made of Ni-Mn-Ga Magnetic Shape Memory (MSM) alloy. As the MSM element is subjected to mechanical stress within an external magnetic field, its magnetization changes in proportion to its length, facilitating energy generation in a pick-up coil. Whereas conventional piezo and magnetostrictive devices operate with small (sub-millimeter) stroke at high frequencies (kHz range), the MSM harvester is best suited to longer (millimeter range) stroke at a low frequency (100 Hz or below). Power output of 20 mW has been demonstrated with the prototype device operating at 45 Hz.