bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation of Nanometer ZnO Compound Particles and Ultraviolet Absorption Properties
Authors: Jia Ying , Wang Xing Yun , Liu Tian Tian , Xu Guo Gen
Published: September 2012

ZnO/TiO2 and ZnO/SnO2 composite nanoparticles were prepared by hydrothermal combined-assisted ethanol method , The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDS), and the uv-vis absorption performance of which was also characterized by uv-vis diffuse reflective spectrum (UV-vis). The results of the research showed that, in ultraviolet-visible absorption spectra diffuse, the maximum absorption peaks of ZnO/TiO2 and ZnO/SnO2 nanocomposite particles were blue-shift comparing to the pure nanometer ZnO, and there were also weak absorption in the visible region.
Wavelength Division Multiplexing between 2.5-Gbits/s Chaotic Optical Secure Channel and 10-Gbits/s Nonchaotic Fiber-Optic Channel
Authors: Chen Xiao Lei , Zhao Qing Chun , Yin Hong Xi , Dou Xin Yu
Published: September 2012

In this paper, we numerically investigate the wavelength division multiplexing (WDM) transmission between chaotic optical secure channel and nonchaotic fiber-optic channel. When the channel spacing is 0.8 nm, a 2.5-Gbits/s message masked by the chaotic optical secure channel and a 10-Gbits/s message carried by the nonchaotic fiber-optic channel can be achieved simultaneously. The results show that the Q-factor of the recovered message can be increased significantly when the launched power is reduced appropriately. The deterioration on the quality of communications caused by fiber dispersion can be compensated obviously when the symmetrical dispersion compensation scheme is adopted. In addition, the message is masked by chaos shift keying in the chaotic optical secure channel. The multiplexing distance between the chaotic optical secure channel and the nonchaotic fiber-optic channel is up to 150 km.
Optical-Mode Study of Galium Nitrate Based Laser Diodes
Authors: Cattarusa Douglas Alan , Jin Xiao Min , Fu Xing Xing , Kang Xiang Ning , Zhang Bei , Zhang Guo Yi
Published: September 2012

This paper focuses on the optical mode analysis of laser diodes to improve light emission. Under the mode analysis, we compare the optical confinement factor (OCF) percentage of the emitting light from the LDs. There are two structures which we analyze: a basic GaN waveguide structure and an InGaN waveguide structure. The second structure has additional InGaN waveguides and is analyzed under two additional design variations: the concentration of Indium and the thickness of the top waveguide layer. The results of this study indicate introducing InGaN waveguide layers correlates with lower order modes (zero and first order) and increase the OCF values. The top InGaN waveguide layer, which has a higher concentration of Indium, appears to increase the OCF. However, the increased thickness of the InGaN layer causes the lower modes’ OFC to decrease. Over all, in the best case, InGaN LD has an OCF of 1.8896%, which is about a 312% improvement compared to that of GaN LD ( OCF=0.4535%).
Frame and Frequency Synchronization for MIMO OFDM Using Symmetric and Repeat Training Sequence
Authors: Liao Ming Xia , Tan Ze Fu , Liu Jing
Published: September 2012

A new improved MIMO-OFDM synchronization algorithm is proposed in this paper. Frame synchronization is performed by the uniqueness of correlating peak value of symmetric sequence. Fractional frequency offset estimation is processed by repeat sequence after frame synchronization. In frequency domain, integer frequency offset estimation is performed based on energy detection in virtual carriers. The performance comparison of the proposed algorithm and Mody’s algorithm by using computer simulation illustrates and verify the superior performance of the proposed algorithm. Especially in bad channel environment, the proposed algorithm also satisfy synchronization requirement.
A SoC for Intelligent Control Systems
Authors: Zheng Zheng Xing , Tang Guo Min , Liu Li Min
Published: September 2012

Intelligent control is a new direction of industrial automation. An intelligent control system is composed of algorithm, software and hardware. SoC is one of the best embedded system hardware. SoC may get some new progress for intelligent control. In this paper, intelligent control, SoC and some intelligent controller based on SoC are discussed. The new controller can be the smaller and more reliable.
A Biosensor for Sandwich Immunoassay by Electrodepositing Redox Polymer on Screen-Printed Carbon Electrode
Authors: Sha Yu Fang , Zhao Mei , Guo Fei , Xie Jun , Han Wei
Published: September 2012

Improvement of sensitivity of electrochemical sandwich enzyme immunoassay has been achieved by electrodepositing redox polymer on screen-printed carbon electrode surface, on which sandwich complex were formed.
Use Skill of External Memory Expansion for DSP of TMS320VC5409
Authors: Huang Liang , Li Xiang Zhi , Zhao Qing Lei , Han Cheng Shan
Published: September 2012

This paper proposes the external data memory and program memory using skills for DSP of TMX320VC5409. Firstly, the memory allocation of TMX320VC5409 is described and the its assembly line operation is analyzed. Secondly, the external program memory space memory structure and external data memory and program memory extension using skills are discussed. Finally, the IS61LV12816 is taken as an example to design the external memory expansion of the hardware and software. The practice has proved that the mode has great flexibility and practicality.
Biological Multilayer Films Assembled by Redox Polymer and HRP on Screen-Printed Carbon Electrode
Authors: Sha Yu Fang , Zhao Mei , Yang Ming Quan , Bai Hai Xin , Zhao Man
Published: September 2012

Biological multilayer films of redox polymer and horseradish peroxidase (HRP) were successfully assembled on a screen-printed carbon electrode using layer-by-layer (LBL) assembled method based on the electrostatic interaction. The screen-printed carbon electrode surface was modified by the positively charged redox polymer, and the negatively charged HRP by LBL method.
Estimation of Dielectric Response Parameters of Transformers Using Hybrid Genetic Algorithm
Authors: Zhang Tao , Li Dong Hui , Ma Fei Lin , Ran Hua Jun
Published: September 2012

It is important to reveal the relationship between the characteristic quantity of return voltage and polarization characteristics of dielectric in theory. In recent years, some researchers have proposed some equivalent circuit models to study the relationship between the equivalent circuit and the characteristic quantity of return voltage. However, seldom shows how the mathematical model of equivalent circuit parameters estimated is established and these parameters are estimated. The initial slope of return voltage is of great significance to identify the parameters of equivalent circuit based on linear dielectric response theory. Therefore, this paper establishes a mathematical model with the data of initial slope of return voltage for estimating its parameter, and then, a hybrid genetic algorithm is used for solving the problem. The result shows that the model established is feasible and effective.
Research Progress of Wavelet Denoising Method of Transformer Partial Discharge Signal
Authors: Zhang Ying , You Fu Cheng
Published: September 2012

Wavelet analysis has been widely used in the denoising of partial discharge signal of transformer. This paper introduces the main method of partial discharge signal denoising, which focuses on the studying of wavelet denoising methods. The main wavelet denoising methods are introduced herein including wavelet decomposition and reconstruction method, wavelet thresholding method, the translation invariant wavelet thresholding method, the wavelet denoising based on modulus maxima method, and the most widely used wavelet thresholding is introduced primarily. The analysis of their advantages and disadvantages is helpful to choose a proper wavelet denoising method.
Preparation and Characteriziation of Cu-Cr Alloy Powders
Authors: Xiao Peng , Zhang Xiao Yu , Lu Hong Wei
Published: September 2012

Cu-1.37Cr alloy powders were prepared by gas atomization process, and the cooling rates of alloy powders were calculated through the convection heat transfer principle. The morphology, distribution of alloy elements and microstructure of Cu-1.37Cr alloy powders were characterized by X-ray diffractometer and Scanning Electron Microscope (SEM).The results show that the cooling rate increases from 9.75×103 to 1.08×105 K/s as grain size decreases from 150 to 45µm. The morphology of alloy powders are spherical or similar spherical shape along with smooth surfaces. The grains have uniform size, and Cr particles are uniformly distributed in Cu matrix. With decrease of particle sizes, the diffraction angle shifts into small angle, suggesting that the larger solubility of Cr in Cu phase.
Simulation Analysis of Output Characteristic of the Inductive Displacement Transducer
Authors: Song Ruo Feng , Song Li Ming , Yang Qian Ming
Published: September 2012

Aiming at the structure and electromagnetic induction characteristics of inductive displacement transducers, it is inevitable to appear the problem between nonlinearity output and temperature drift, by which it’s testing accuracy is affected, on the basis of analysis of structural characteristics and working principle of the inductive displacement sensor, mathematical model of the relationship between input and output has been constructed, which can be simulated and analyzed by MATLAB software. The results indicate that the inductive displacement transducer has an proximately linear extent ( ) and the linearity errors are influenced by the coils number and the semidiameter;In the case of relatively constant of other parameters, when the coil of radius and the number of coil turns are fixed ,there will be the core displacement x and , the sensor output characteristic has an favorable linearity under the circumstances of changing the coil radius and the number of turns in proper sequence; When ,the output property of the sensor appears worse linearity.
Research on Design of Cable Wireless Temperature Monitoring System
Authors: Yu An Qi , Hu Hong Sheng
Published: September 2012

In this paper, a wireless temperature monitoring system was designed for cable based on Labview software, where its designed frame form and realization method were introduced. MSP430 MCU UART serial communication and generic personal-computer was selected as the main hardware part, and a suit of monitoring-controlling user software was also developed by using the Labview. Compared to the traditional measuring system, the developed cable wireless temperature monitoring system takes on some characters, such as good maneuverability, common good, strongly functions and high of performance-price ration. Besides, the developed wireless temperature monitoring system has an automatically data sampling function and an remote on-line monitoring function in real time, which could be widely applied into temperature measurement in electric power system.
An Improved Frame Synchronization for Optical OFDM Systems
Authors: Liang Meng , Lu Rong , Wang Yuan Bo , Gong Jia Min
Published: September 2012

Orthogonal frequency division multiplexing (OFDM) is applied to optical communication widely because of its robustness against channel dispersion and high spectral efficiency. But the synchronization between transmitter and receiver is a critical factor for system performances. This paper proposes an improved frame timing synchronization algorithm for optical OFDM system to keep synchronization by delay time compensation. The simulation of 40 Gb/s single-side-band (SSB) direct-detection optical OFDM system is setup and investigated. The curve of timing metric and the constellation of four-quadrature amplitude modulation (QAM) are given in the paper. And the transmission distance using the proposed method is compared with Park method. The simulation results show that the improved frame synchronization method promote the performances of optical OFDM system greatly. The distance can be 1600 km without dispersion compensation under the bit error ratio of 10-4.
Study on Enhancement of Convective Heat Transfer in Nanofluids
Authors: Zhang Lei
Published: September 2012

Nanofluids are a new class of heat transfer fluids and offer an important advantage on conventional heat transfer fluids. The nanometer-sized metallic and non-metallic solid particles or tubes are dispersed in base heat transfer fluids such as water, engineering oil and emulsion. It is a interdisciplinary field between nanoscience, nanotechnology, and thermal engineering. The nanofluids study work attracts a lot of interest from the worldwide researchers because of their fascinating thermal characteristics and potential applications in microelectronics, transportation and biomedical fields. Many important theoretical and experimental study works on convective heat transfer appeared in literature. The purpose of this article is to study theoretical and experimental findings on the enhancement of the convection heat transfer with nanofluids and analyze the key factors of thermal conductivity and convective heat transfer enhancement with nanofluids.
Application with Wavelet Detection to Signal Process of SINS
Authors: Huang Xiang Yuan , Tang Xia Qing , Guo Li Bi , Cheng Xu Wei
Published: September 2012

Aimed at disturbance caused from motor running and personnel ambulation during initial alignment process of SINS, a new signal detection method of disturbance based on wavelet analysis is brought out. Through analyzing original signal characteristic of FOG and the data with wavelet filter on disturbance base, finds out wavelet filter just have effectiveness to high frequency noise. Then T&L signal detecting law is introduced, and builds T&L signal with high frequency part of wavelet decomposing to estimates interfere time and then resample. Offline simulation experiment results indicate the method can eliminate low frequency disturbance effectively and has certain apply value.
Design of the Instrument of Measuring Moisture Ratio in Textile Fibre Based on Integrate Circuit CAV424
Authors: Xu Qi Ying , Yang Li Kun
Published: September 2012

The paper discusses a new instrument design method about quickly measuring moisture ratio in textile fibre based on the relation of moisture ratio and its relatively dielectric medium constant. Introduces the integrate circuit CAV424 used for capacitance to voltage signal convert; the test-result shows that the instrument can substitute traditional methods to improve fibre moisture testing technique in textile industries.
Fast Angle Estimation Based on MSWF and Polynomial Rooting for Monostatic MIMO Radar
Authors: Gong Jian , Wang Chun Yang , Li Hong Bing
Published: September 2012

A novel method employing Multi-Stage Wiener Filter (MSWF) and polynomial rooting is proposed for the one-dimensional angle estimation of MIMO radar. In this algorithm, the signal subspace is obtained using MSWF, which avoids the known expected signal, the estimation of the virtual data autocorrelation matrix and eigen-decomposition. Then, a polynomial rooting is adopted to realize angle estimation. The effectiveness of the proposed method is verified by numerical examples.
Research for Thermal Drift of APD Gain in Distributed Temperature Sensing System Based on the Raman Back-Scattering
Authors: Sang Lei , Zhang Jie , Wang Xin Qun
Published: September 2012

In the temperature measurement system of distributed optical fiber based on Raman back-scattering, the temperature measurement depends on a series of laser pulses in the optical fiber, which produces anti-stokes and stokes lights of Raman back-scattering at various points. By using the ratio of them, the measurement of temperature field space can be realized. But the signals that can be gained are quite weak in practice, and there are interferences of noises and external signals, therefore APD is selected (Avalance Photodiode) to amplify the weak signals. Because the gain characteristics of APD are vulnerable to the influences of temperature and bias voltage, so in this paper the experiments were carried on about the effects of temperature, bias voltage, incident power etc. on APD, and a substantive discussion was discussed.
Microstructure and Behavior of Laser Cladding SiC + Ni-WC Ceramic Coating on H13 Steel
Authors: Yang Qiu He , Shen Shu Jun , Wang Li Xia
Published: September 2012

To obtain high properties of laser cladding layer, and to expand the service life of the mold, the laser cladding layer with Ni-WC and SiC on the surface of H13 steel made by using a laser. Then the cross-section and surface morphologies of the coatings and wear tracks were observed with a JSM-5610 type scanning microscope. The friction and properties were examined under dry sliding conditions using a WTM-1E type ball-on-disc machine. The wear mechanisms are discussed as well. The results show that the composite coating is very compact and good blinding with the substrate after laser remelting, and the wear mass loss of the composite coating reduced to about 1/4 of the matrix material.
Chromogenic Windows
Authors: Granqvist Claes Goran
Published: September 2012

Chromogenic materials and devices allow the construction of glazings whose throughput of visible light and solar energy can be varied depending on the application of an electrical voltage or temperature. These glazings are of much interest for energy efficient buildings and are able to create energy efficiency along with indoor comfort. This paper outlines the basics of electrochromic and thermochromic technologies with foci on functional principles, materials, device and manufacturing technology, and selected results from research and development.
Inorganic Nanoparticles for either Charge Storage or Memristance Modulation
Authors: Tsoukalas Dimitris , Verrelli Emanuele
Published: September 2012

We present prototype memory devices using metallic and metal oxide nanoparticles obtained by a physical deposition technique. The two memory device examples demonstrated concern the use of platinum nanoparticles for flash-type memories and the use of titanium oxide nanoparticles for resistive memories. Both approaches give interesting device memory properties with resistive memories being still in an early exploratory phase.
Controlling Electromagnetic Wave Based on Magnetic Metamaterials
Authors: Liu Shi Yang , Lin Zhi Fang , Chui S.T.
Published: September 2012

Metamaterials are composite artificial materials composed of sub-wavelength resonant building blocks designed with state-of-the-art configurations, which exhibit novel and unique electromagnetic (EM) properties. The building blocks are usually made of metallic material, where surface plasmon polaritons can be excited at the interface, leading to many interesting and promising phenomena and applications. However, some drawbacks are accompanied such as intrinsic loss, narrow working frequency, and tunability limitation. We have designed a class of metamaterials composed of building blocks made of ferrite materials, it is accordingly termed magnetic metamaterials (MM). It is demonstrated that with the MM we can construct a magnetically tunable negative index material with the impedance matched to the air. The excitation of the magnetic surface plasmon (MSP) resonance can also be observed in the MM. Due to the MSP resonance and the time reversal symmetry breaking nature of the MM, the unidirectional waveguiding of the EM wave is demonstrated.
Nonlinear Backward-Wave Photonic Metamaterials
Authors: Popov Alexander K. , Shalaev Mikhail I. , Slabko Vitaly V. , Myslivets Sergey A. , Nefedov Igor S.
Published: September 2012

Novel concepts of nonlinear-optical (NLO) photonic metamaterial are proposed. They concern photonic materials that support backward electromagnetic or vibration waves (BWs) and provide coherent nonlinear-optical energy exchange between ordinary and BWs as applied to three- and four-wave mixing processes. Three different classes of materials which support BWs are considered: plasmonic negative-index (NI) metamaterials (NIMs), metamaterials with specially engineered spatial dispersion of the nanoscopic building blocks, such as standing carbon nanotubes, and crystals that support optical phonons with negative group velocity. The possibility to exploit ordinary crystals instead of plasmonic NLO metamaterials that are very challenging to engineer is proposed. It is shown that extraordinary nonlinear optical frequency-conversion propagation processes attributed to NIMs can be mimicked in the proposed metamaterials. It is also shown that the detrimental effects of strong losses can be mitigated in the short-pulse regimes, which exhibit exotic properties when ordinary and BWs are involved in the NLO coupling. Comparative review of unparallel properties of coherent energy exchange between ordinary and backward electromagnetic waves in NIMs and between ordinary electromagnetic waves coupled through backward vibration waves is given. Unique photonic devices are proposed.
Dielectric-Tuned Diamondlike Carbon Materials for an Ultrahigh-Speed Self-Aligned Graphene Channel Field Effect Transistor
Authors: Takabayashi Susumu , Yang Meng , Ogawa Shuichi , Takakuwa Yuji , Suemitsu Tetsuya , Otsuji Taiichi
Published: September 2012

The ‘DLC-GFET’, a graphene-channel field effect transistor with a diamondlike carbon (DLC) top-gate dielectric film, is presented. The DLC film was formed ‘directly’ onto the graphene channel without forming passivation interlayers using our photoemission-assisted plasma-enhanced chemical vapor deposition (PA-CVD), where the plasma was precisely controlled by significant photoemission from the sample with quite low electric power, minimizing plasma damage to the channel. The DLC-GFET exhibits clear ambipolar characteristics with a slightly positive shift of the neutral points (Dirac voltages). Relatively high transconductances were obtained as 14.6 (8.8) mS/mm in the n (p) channel modes, respectively, with a thick DLC gate dielectric of 48 nm and a long gate length of 5 μm, promising vertical scaling-down to improve the high-frequency performance. The positive shift of the Dirac voltage is due to unintentional hole doping from an oxygen species like H2O in the DLC film into the graphene channel, suggesting that a modulation-doped DLC structure with a δ-doped oxygen (nitrogen) species for the p (n) mode will overcome high access resistance.
Impact of Sputter Deposition Parameters on the Leakage Current Behavior of Aluminum Nitride Thin Films
Authors: Schneider Michael , Strunz Tobias , Bittner Achim , Schmid Ulrich
Published: September 2012

In microelectromechanical systems, piezoelectric aluminum nitride (AlN) thin films are commonly used as functional material for sensing and actuating purposes. This is due to excellent dielectric properties as well as a high chemical and thermal stability of AlN. In this work, we investigate the leakage current behavior (i.e. IV characteristic and charging behavior) of AlN thin films sputter deposited at varying plasma powers (300 W – 800 W) and deposition pressures (4 µbar – 8 µbar) up to an electric field of 0.5 MV/cm. First results show a Poole-Frenkel behavior for all samples with an increase in leakage current by orders of magnitude as the degree of c-axis orientation decreases. In addition, the discharging curves (i.e. meaning the current discharge after an applied constant electric field) agree well with the empirical Curie - von Schweidler Law (I(t) = I0 + I1t-n) and an increase of the parameter I1 with temperature is observed. I1 shows qualitatively the same behavior as the overall stored charge. Furthermore, the results show a strong negative correlation between the parameters n and the time constant τ1/2 (i.e. defined as the time after which half the stored charge has decayed), proofing that n is a good indicator for the decay time of the stored charge.
Tailored One-Way and Two-Way Shape Memory Response of Poly(ε-Caprolactone)-Based Systems for Biomedical Applications
Authors: Pandini Stefano , Passera Simone , Riccò Theonis , Borboni Alberto , Bodini Ileana , Vetturi David , Dassa Luca , Cambiaghi Danilo , Paderni Katia , Degli Esposti Micaela , Toselli Maurizio , Pilati Francesco , Messori Massimo
Published: September 2012

A series of crosslinked poly(ε-caprolactone) (PCL) materials were obtained starting from linear, three- and four-arm star PCL functionalized with methacrylate end-groups, allowing to tune the melting temperature (Tm) on a range between 36 and 55°C. After deforming the specimens at 50% above Tm, the materials are seen to fully restore their original shape by heating them on a narrow region close to Tm; further, when the shape memory effect is triggered under fixed strain conditions, the materials are able to exert stress on a range between 0.2 and 7 MPa. The materials also display two-way shape memory features, reversibly moving between two shapes when cooled and heated under a fixed load. Finally, to investigate the application of the PCL materials as self-expandable stents, one-way shape memory experiments are currently carried out on tubular specimens.
Photoresponsive Liquid Crystalline Polymeric Materials
Authors: Liu Dan Qing , Van Oosten Casper , Bastiaansen Cees W.M. , Broer Dirk J.
Published: September 2012

In-situ photopolymerization of liquid crystalline (LC) monomers has proven to be a valuable technique for the formation of well-ordered polymer networks. Their anisotropic properties led to a variety of applications in optics, electronics and mechanics. The use of light to initiate polymerization enables lithographic patterning. In addition the LC behavior enables formation of complex morphologies on molecular level. Controlling the director profile of an LC network film in transversal direction gives geometrical morphing upon minor changes in order parameter. Examples of suited profiles of molecular orientation are twisted or splayed director configurations tied up in the network configuration. Reversible order parameter changes can be induced by light using the photo-activated trans-cis isomerization of a copolymerized azobenzene monomer. This is demonstrated in photoresponsive cilia inkjet printed on a substrate. The cilia possess a splayed molecular organization and show well-controlled bending when addressed by light. We demonstrate a patterned film with alternating helicoidal and perpendicular-uniaxial molecular orientation. When applied as coating on glass, photo-activation in this case leads to a dynamically switching surface topology
Magnetic Field Induced Formation of Magnetic Wires into Thin Elastic Membranes with Controlled Properties
Authors: Lorenzo Daniela , Fragouli Despina , Anyfantis George C. , Cingolani Roberto , Athanassiou Athanassia
Published: September 2012

We present the fabrication of magnetic elastomeric membranes consisting of aligned superparamagnetic microwires embedded in a polymeric matrix. The wires are formed by the magnetic assembly of colloidal iron oxide nanoparticles (NPs) dispersed in the prepolymer matrix, during the curing of the polymer and the solvent evaporation. The appropriate combination of the NPs quantity and of the viscosity of the matrix results in the formation of thin membranes of about 10mm, containing few layers of aligned wires which after the polymer curing are blocked in fixed position into the matrix. The orientation and the dimensions of the magnetic wires depend on the direction and intensity of the external MF respectively.
Soft Microorigami: Stimuli-Responsive Self-Folding Polymer Films
Authors: Ionov Leonid , Zakharchenko Svetlana , Stoychev Georgi
Published: September 2012

Asymmetry is intrinsic to natural systems and is widely used by living organisms for efficient adaptation, mimicry and movement. Polymer bilayers are the example of synthetic asymmetric systems, which are able to generate macroscopic motion and fold by forming different 3D objects such as tubes and capsules. Similar to bimetal films, the polymer bilayer consist of two substances with different swelling properties. One polymer is non-swellable and hydrophobic. Another polymer is water-swellable hydrogel. The folding, which might occur in response to temperature or pH, is caused by swelling of the hydrogel layer. The formed tubes and capsules can be manipulated using magnetic field. Reversible folding and unfolding of the polymer films is applied for reversible capture and release of cells in response to change of temperature and other signals. This novel biomimetic approach can be used for controlled encapsulation and release of microparticles, cells and drugs as well as fabrication of 3D scaffolds for tissue engineering.
Ceramics PMN-PT-PFN for Multilayer Capacitors
Authors: Bochenek Dariusz , Skulski Ryszard , Wawrzała Paweł , Niemiec Przemysław
Published: September 2012

We present the technology of the solid solution with formula (1-y)[(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3]-yPb(Fe1/2Nb1/2)O3 where x=0.25, y=0.1 i.e. 0.9(0.75PMN-0.25PT)-0.1PFN. The addition of PFN decreases the temperature of final sintering and as a result such composition is interesting material for multilayer ceramic capacitors (MLCC). 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 and PbO and TiO2. For obtained ceramics the following investigations have been made: XRD patterns, microstructure, EDS and main dielectric properties v.s. temperature. It has been stated that obtained ceramic powder is a good material for obtaining MLCC
Comparison of the Long-Term Stability of TiO2 Hydrosols with Different Concentration of Nanoparticles
Authors: Pavlova-Verevkina Olga , Golubko Natalia , Sumbatov Alexander , Ozerina Ludmila
Published: September 2012

The long-term stability of two TiO2 hydrosols with concentration of TiO2 nanoparticles 1 and 12 mass.% was compared by turbidimetry and dynamic light scattering. The both sols were stabilized by HCl at pH=0.5. It was found that the mean hydrodynamic radius of particles and the turbidity of the sols increased slowly for six months of investigation and the kinetics of the “ageing” of the sols did not depend on TiO2 concentration. The obtained results will enable to determine mechanisms of the slow growth of nanoparticles and to modify nanoparticles structure.
Study on the Fabrication of Visible Light Response Type N-Doped TiO2 Photocatalyst by SPS
Authors: Kikuchi N. , Asaoka T.
Published: September 2012

It is recognized that TiO2, the most popularly used photocatalyst, has a disadvantage that it only react with ultraviolet light. In this study, nitrogen-doped TiO2 was selected as strategy for promoting the absorption of visible light, and SPS (spark plasma sintering) method was tried to fabricate a dense specimen without using binder materials. Preparation methods of specimen are as follows; yellow-colored N-doped TiO2 powders were synthesized from a mixed aqueous solution containing TiCl3 and NH3. The precipitate was air-dried for 1 week. Then dried in a drying oven for 1day(50°C). And heat-treated for 1h(400°C).N-doped TiO2 powder and non-doped TiO2 powder were sintered by SPS at 400 or 700°C. N-doped TiO2 fabricated by SPS showed a favorable crystal structure of anatase, and successful existence of doped nitrogen was confirmed by XPS analysis. UV-vis results showed that N-doped TiO2 responded to visible light, which indicates an increasing possibility of this type of photocatalyst. Further study to extend the range of absorption wavelength is carrying out.
Calix[4]Arenes Appended with Thioamide Moieties as Powerful Tool for Heavy Metals Recognition
Authors: Kulesza Joanna , Alves Júnior Severino , Guziński Marcin , Bocheńska Maria , Hubscher-Bruder Véronique , Arnaud-Neu Françoise
Published: September 2012

Selectivity of new thioamide derivatives was assessed using those ligands as sensor materials in ion-selective membrane electrodes and tested towards Pb2+ - selectivity. The influence of the nature of the thioamide function (linear, branched or cyclic substituents) on their ionophoric properties was investigated. Electrodes based on cyclic thioamide moieties are promising analytical tools for monitoring Pb2+ concentration in natural and drinking waters.
Novel Adaptive Damping Systems Based on Magnetorheological Fluids
Authors: Böse Holger , Ehrlich Johannes
Published: September 2012

Adaptive damping systems based on magnetorheological (MR) fluids allow the continuous control of vibration damping forces depending on the current conditions. In magnetorheological dampers known so far, the magnetic field for the control of the MR fluid is generated by the coil of an electromagnet. Two novel concepts for the magnetic circuit in magnetorheological dampers have been proven where hybrid magnetic circuits consisting of at least one permanent or hard magnet and an electromagnet are used. In the first concept, the electromagnet is combined with two permanent magnets, whose magnetization cannot be modified even by strong magnetic fields of the electromagnet. The main advantage of this configuration is the improved fail-safe behaviour of the damper in case of a power failure. In the second approach, the electromagnet is combined with a hard magnet, whose magnetization can be modified by the electromagnet. This configuration leads to high energy efficiency, because electric power is only required in short pulses for the switching of the hard magnet. Magnetic circuits with the combination of different magnetic field sources were designed supported by simulations of the magnetic flux distribution. Demonstration models for magnetorheological dampers with the distinguished magnetic circuits were constructed and their performances were tested. The results of the investigations are described in this contribution.
The Effect of Pressure on Martensitic Phase Transformations
Authors: Paidar Vaclav , Ostapovets Andriy , Hardouin Duparc Olivier
Published: September 2012

Stability of the crystal structure is determined by the competition between attractive and repulsive interatomic forces. Using many-body exponential potentials it can be shown that the bcc structure corresponding to austenitic phases is more stable for low values of the q-parameter characterising the attractive forces for a fixed value of the p-parameter describing the repulsive forces. The structural stability can be changed with the acting pressure that may alter the martensitic transformations from the bcc-austenite to a close-packed structure. The effect of pressure is examined in a generic model employing many-body potentials and the results are compared with ab initio calculations for zirconium representing a monoatomic material with displacive phase transformation.
Heat-Treatment Processing for MnBi in High Magnetic Fields
Authors: Watanabe Kazuo , Mitsui Yoshifuru , Koyama Keiichi
Published: September 2012

The phase diagram for MnBi was investigated in high fields up to 18 T at temperatures ranging from 300 to 730 K. We used the differential thermal analysis (DTA), in order to examine the equilibrium phase change of ferromagnetic MnBi by applying high magnetic fields. In particular, the first-order magnetic phase transition to the paramagnetic phase at the decomposition temperature Tt ~ 628 K for ferromagnetic MnBi was evaluated in fields up to 26 T. It was found that Tt increases with increasing magnetic fields at the rate of 2 K/T in low fields up to 18 T, and clearly deviates from the linear increase above 20 T. From a viewpoint of application, it is important that the decomposition of MnBi can be controlled by a magnetic field. As a result, Tt on the liquid phase line changes the amount of Mn content from 10 to 16.5at.% at 26 T, and the heat-treatment at 26 T improves the volume fraction of MnBi. Further, it is quite interesting to directly synthesize ferromagnetic MnBi from the liquid phase without the paramagnetic phase transformation.
CuZnAl Shape Memory Alloys Foams
Authors: Tuissi Ausonio , Bassani Paola , Biffi Carlo Alberto
Published: September 2012

Foams and other highly porous metallic materials with cellular structures are known to have many interesting combinations of physical and mechanical properties. That makes these systems very attractive for both structural and functional applications. Cellular metals can be produced by several methods including liquid infiltration of leachable space holders. In this contribution, results on metal foams of Cu based shape memory alloys (SMAs) processed by molten metal infiltration of SiO2 particles are presented. By using this route, highly homogeneous CuZnAl SMA foams with a spherical open-cell morphologies have been manufactured and tested. Morphological, thermo-mechanical and cycling results are reported.
SMA Dampers for Cable Vibration: An Available Solution for Oscillation Mitigation of Stayed Cables in Bridges
Authors: Torra Vicenç , Isalgue Antonio , Auguet Carlota , Casciati Fabio , Casciati Sara , Terriault Patrick
Published: September 2012

Several solutions have been proposed to mitigate the vibrations of stay cables in bridges, which are subjected to wind, rain and traffic loads. One possible solution relates to the use of semi-active devices, such as the ones based on magneto-rheologic fluids. These devices need guaranteed electrical power, together with computational effort and technical attention. In contrast, shape memory alloy (SMA) wires were studied for application as passive elements. In the present work, the properties of SMA that are required to realize dampers provided with an appropriate reliability are discussed. In particular, the fatigue/fracture life of the SMA wires and the thermal effects induced by both external temperature and the self-heating process are studied. The SMA dampers were applied to stayed cables of realistic size and tested in "facilities." Namely, the cables No 1 of 45 m length available at the ELSA-JRC in Ispra, Italy, and the 50 m cable of IFSTTAR near Nantes, in France, were considered. The experimental results establish a reduction of the vibration amplitude to one half or less than the one observed in the un-damped case. Furthermore, the installation of the SMA dampers causes an increase of the cable frequency. Performing a Windowed Fourier Transform or a Wavelet Transform analysis the evolution of frequency with the signal amplitude was studied. The change of amplitude produces a change of stiffness in the SMA. The adoption of an appropriate phenomenological model of the hysteresis cycle permits to perform numerical simulations using standard Finite Elements Analysis tools such as, for instance, the ANSYS software.
Chitosan/IPMC Artificial Muscles
Authors: Shahinpoor Mohsen
Published: September 2012

This presentation discusses how biopolymers such as chitosan and ionic polymer metal composites (IPMCs) can be combined by intercalation and co-polymerization to form a new nanocomposite with actuation, energy harvesting and sensing capabilities and yet have medical healing and diagnostics capabilities. Described are chitosan and ionic polymeric networks containing conjugated ions that can be redistributed by an imposed electric field and consequently act as distributed nanosensors, nanoactuators and artificial muscles. The presentation briefly discusses the manufacturing methodologies and the fundamental properties and characteristics of such chitosan/ionic polymers as distributed nanosensors, nanoactuators and artificial muscles. It will further include descriptions of the basic materials' typical molecular structures. An ionic model based on charge dynamics of the underlying sensing and actuation mechanisms is also presented. Intercalation of chitosan biopolymer and ionic polymers such as perfluorinated sufonic ionomers and subsequent chemical plating of them with a noble metal by a REDOX operation is also reported and the properties of the new product are briefly discussed.
Properties of a Dielectric Elastomer Actuator Modified by Dispersion of Functionalised Carbon Nanotubes
Authors: Galantini Fabia , Bianchi Sabrina , Castelvetro Valter , Anguillesi Irene , Gallone Giuseppe
Published: September 2012

Among the broad class of electro-active polymers, dielectric elastomer actuators represent a rapidly growing technology for electromechanical transduction. In order to further develop this applied science, the high driving voltages currently needed must be reduced. For this purpose, one of the most promising and adopted approach is to increase the dielectric constant while maintaining both low dielectric losses and high mechanical compliance. In this work, a dielectric elastomer was prepared by dispersing functionalised carbon nanotubes into a polyurethane matrix and the effects of filler dispersion into the matrix were studied in terms of dielectric, mechanical and electro-mechanical performance. An interesting increment of the dielectric constant was observed throughout the collected spectrum while the loss factor remained almost unchanged with respect to the simple matrix, indicating that conductive percolation paths did not arise in such a system. Consequences of the chemical functionalisation of carbon nanotubes with respect to the use of unmodified filler were also studied and discussed along with rising benefits and drawbacks for the whole composite material.
Actuation of Model Phalanges by Ion Polymer Metal Compound
Authors: Ihara Tadashi , Nakamura Taro , Asaka Kinji
Published: September 2012

We have fabricated a prototype model artificial muscle that drives model phalanges in water with ion polymer metal compound (IPMC) which generates relatively large displacement with fast response but generates relatively small force. We have developed IPMC of greater thickness of up to 600 µm than conventional Nafion 117 based IPMC of 200 µm which enabled to generate greater force. In fabricating IPMC Nafion R-1100 resin was heat-pressed at 185 °C with 20-30 MPa. The thickness of IPMC could be adjusted by changing the amount of resin, pressure, and time to heat-press. Fabricated IPMC was then cut in shapes and an electrode was attached on the surface of IPMC. The device was used as an artificial muscle type actuator which was fabricated in a shape that bridges two conjoining bones, and controls opening angle of the bones that mimics contraction and expansion motion of the muscle. Bipolar power supply and function generators were used to drive IPMC membranes attached to the model phalanges.
PVDF Sensors – Research on Foot Pressure Distribution in Dynamic Conditions
Authors: Klimiec Ewa , Zaraska Wiesław , Piekarski Jacek , Jasiewicz Barbara
Published: September 2012

The paper presents a dynamic measurement method of the distribution of foot pressure exerted on the ground by a four-point shoe insole, developed by authors, which can be placed in any sport footwear. The value of pressure was measured on the heel, medial midfoot, metatarsal, and great toe by recording values of a generated voltage by sensors which were made of piezoelectric polymer PVDF film 110 µm thick with printed silver electrodes. As confirmed by scanning microscope studies, the foil applied in the sensors is semi-crystalline. The shoe measurement insert consists of two polyester films without piezoelectric properties between them, electroactive polymer sensors were placed. The films were glued together. To match the measuring circuit to the sensors used, two circuits were tested, a voltage measuring circuit with an input resistance of above 1012 Ω (open circuit), and a charge measuring circuit (shorted circuit). The charge measuring circuits with the RC high-pass filter, which attenuates the slow-changing pyroelectric signal was selected as it ensures the desired measurement accuracy. As presented in the paper, as PVDF sensors are very sensitive to any mechanical deformation, it is important to properly design the shoe insole to ensure its correct use during pressure distribution measurements. The measuring system developed by the authors, allows testing of foot pathology for any length of time in a dynamic way.
Washable Screen Printed Textile Antennas
Authors: Kazani Ilda , Scarpello Maria Lucia , Hertleer Carla , Rogier Hendrik , de Mey Gilbert , Guxho Genti , Van Langenhove Lieva
Published: September 2012

The wireless communication systems are applied in different applications such as computers, mobile phones, satellites and antennas for off-body communication. A lot of efforts were made to have the antennas in a smaller size, flat and with better performance. In the last decade the rigid antennas are replaced with textile in order to be flexible and to be integrated into garments in order to have wearable textile systems. The textile antennas can find use in medical, military and first responders monitoring. The conductivity of the antennas can be achieved by using coated textile materials which are available in the market, conductive threads for embroidery or conductive inks. When using the conductive coated textile it is necessary to cut the patch in the desired pattern but using a simple cutting tool sometimes is not very precise and accurate. Thus in our study we decide to screen print with silver conductive inks on Polyester and Cotton/Polyester substrates. The screen printed antennas are than washed in order to conform that antennas for off-body communication integrated in garments can be easily washed five times.
Classified Catalogue for Textile Based Sensors
Authors: Bosowski Patrycja , Husemann Christian , Quadflieg Till , Jockenhövel Stefan , Gries Thomas
Published: September 2012

Technical textiles are used primarily for their technical functionality in many different industries. For monitoring the functionality of textiles it is possible to integrate sensors into the textile. Since textiles are made of fibres, yarns, two-or three dimensional structures the sensor systems should accordingly be designed as a part of them. Smart textiles are concerned with textile based sensors integrated mechanically and structurally to a textile. The state of the art in developing textile based sensors extends from sensor fibres to over coated yarns and textiles but without using standardized tools. The development of a textile sensor and its interpretation on a specific application has been associated with many investigations into combination of different conductive materials, what is a lengthy and costly developing process. Knowledge has already been generated on textile sensors, which now requires an appropriate classification and structure. A classified catalogue which allows a direct selection of textile based sensor modules on the basis of measured values. The catalogue´s structure follows, apart from the VDI- guideline 2222, of which complex coherences can be arranged and a clear representation can be found. Setting standards in the field of smart textiles helps companies to produce more smart products.