bluuebunny/crossref_metadata_2025 huggingface dataset:
The Prospect of Application of Nanometer Material in Oil Exploitation
Authors: Zhu Shi Dong , Zhang Jian Jun , Shi Jun Feng , Zhao Rui Dong , Liu Meng , Shu Yong
Published: March 2012

Emerging of nanotechnology represents development and achievements of modern materials science. Petroleum industry nowadays plays a leading role in development of energy industry. Therefore, the combination of the two is a valuable research subject. The prospect of application of nanometer material in injection-production, tertiary oil production, well sensing and imaging system and coating technology is presented herein. In addition, issues with respect to application of nanometer material in oil exploitation are discussed. Nanometer material and nanotechnology is the frontier technology in science and technology development in the past decades. It is predicated that today's ordinary original material be replaced by nanometer material and nanotechnology be a "key technology"[1] that will surpass internet and genetic technology.
The Interface Design of a Dot Matrix Liquid Crystal Display
Authors: Zhang Cheng Shan
Published: March 2012

A new LCD interface design is put forward in this paper. The design solves the problems of taking too much time to deal with data and different interfaces which exists in common LCD. With this method, it is not necessary to proceed time-consuming LCD control and dot matrix operation, which is in favor of real-time processing of mass data by controller.
The Growth of Si on SiC Complex Substrate by CVD
Authors: Cheng W. , Han P. , Yu F. , Yu L. , Cheng L.H. , Lu H. , Xie Z.L. , Xiu X.Q. , Zhang R. , Zheng Y.D.
Published: March 2012

In this work, the Si layer is deposited on the SiC complex substrate which is composed of Si(111) substrate and 3C-SiC film grown on it. These Si and 3C–SiC films grown under different temperatures in a chemical vapor deposition system are analyzed. The crystalline orientation, the crystalline quality and the conduction type of the films are measured by X-ray diffraction, Raman scattering ,Scanning electron microscope, and 1150 °C is found the optimized temperature for the epitaxial growth of SiC film grown on the carbonized layer. Measurement results also show that the epitaxial layer is n-type 3C-SiC which has the same crystalline orientation with the Si (111) substrate. Si film grown on the SiC complex substrate under the temperature of 690 °C has the best crystalline quality. This film is composed of p-type monocrystal Si and has the same crystalline orientation with the substrate.
The Synthesis and Ion-Exchange Property of Li+ Memorized Inverse Spinel Al0.75Fe1.25(PO4)2
Authors: Jiang Jin He , Shan Bin
Published: March 2012

Compound Al0.75Fe1.25(PO4)2, a inverse spinel-type metal compound, was prepared by a solid state reaction crystallization method. The Li+ extraction/insertion with this material were investigated by X-ray, FT-IR spectroscopy, and Kd measurement, The chemical analysis showed that the Li+ extraction/insertion be progressed mainly by an ion-exchange mechanism. The acid treated samples had an ion exchange capacity of 4.0mmol/g for Li+. It had a memorial ion-sieve property for Li+.
Theoretical Investigations of the High-Pressure Optical Properties of γ-Si3N4
Authors: Chen Dong , Xiong Bao Ku
Published: March 2012

The high-pressure optical properties of the spinel γ-Si3N4 material have been calculated by the plane-wave pseudo-potential method. Our calculated lattice constant is in agreement with the theoretical results and available experimental data. γ-Si3N4 can be used as anti-reflection coatings in the energy range of 10eV～21eV due to high reflectivity. The electromagnetic wave (frequency: 8eV～17eV) can easily traverse the γ-Si3N4 crystal. The peak of the energy loss function is located around 22eV. More importantly, our calculated dielectric constant is 4eV (at 30GPa), which is in agreement with the calculated value.
The Comparative Analysis of Cushion or Shock Absorption Characteristic of Commonly-Used Cushion Packaging Materials
Authors: Du Zhen Jie , Gao Wan Yu , Kang Hai Hong , Liu Sheng Jun , Hu Ming Xi , Sun Xiao Jun , Tian Feng
Published: March 2012

The purpose and method of this paper is to comparatively analyze several commonly-used cushion packaging materials, obtain their shock absorption characteristic curves, and by doing such, provide reference information for cushion packaging design and research. With the static test, dynamic compression test and vibration transfer test carried out, the cushion coefficient ~ static stress curve, maximal acceleration ~ static stress curve and vibration transfer rate ~ frequency curve are gained. A final conclusion is educed that in practical design routine, rational choice of cushion packaging materials, scientific design of packaging structure and validation of anti-vibration capability are relative to those three curves.
Influence of Cutting Parameters and Tool Geometric Angles on TC4 Titanium Alloy Chip Shape
Authors: Wu Wei Hua , Chen Wen Min , Wang Xue Hui , Zhao Can
Published: March 2012

To select reasonable cutting parameters, improve the processing surface quality, and extend the tool life, this paper uses four solid carbide end milling tools to process TC4 titanium alloy, and analyses the influence of the difference cutting parameters and the geometric angles to chip shape. The experiment results indicate that the degree of serrated chip shape is increased by increasing the feed rate under the condition of certain spindle speed. But the degree of serrated chip shape may be decreased by the adoption of small axial and radial depth, or bigger rake angle and smaller helix angle. Select larger rake angle, cutting edge is sharp, the metal deformation of cutting layer is small, which can reduce the friction force when chip flowing through the tool rake face, so that the cutting force and cutting temperature decreases accordingly.The greater the helix angle is, the worse the chip removal conditions is, and the degree of serrated chip becomes larger, the blade is more sharp, easily crack, and the tool life decreases. So relatively small helix angle is better. The choice of angles is interrelated with each other, the selection of some angle separately cannot get the desired reasonable value.
Nonlinear Optimal Tracking Control of Valve-Controlled Asymmetrical Cylinder
Authors: Chen Jia , Xing Ji Feng , He Xi Guang
Published: March 2012

Considering the complex nonlinearities of valve-controlled asymmetrical cylinder, a more accurate nonlinear state-space model is established. Then, states feedback linearization technique is introduced to linearize the model exactly and the stability of inner subsystem is analysised by zero dynamics method with the specific system parameters. Based on the linearized model, optimal control theory is applied to design a nonlinear optimal tracking controller and confirmatory simulation experiments are carried out. The results reveal that, the controller is reasonable and effective, and shows splendid performance in tracking various inputs with a high level of robustness and strong abilities to keep undisturbed by load varying.
Plane Non-Circular Curve Outline Parts’ Relative Constant Motion Modelling and Error Analysis
Authors: Wu Rui , Li Hong Tao , Xu Yuan Kui
Published: March 2012

The planar non- circle curve component’s relative rotative movement was anaysised in this paper, Because the pure mathematics model applies with difficulty in the real issue , With equal interval angle line replaced the smooth contour curve, A simplified mathematical model about movement was establishde, Compare with theory result, the simplified mathematical model could give a right result when the angle intervalδ<3 and the speed is 3~5mm/s. the model could be used in the processing of plane non-circular curve profile parts and induction quenching.
Research on Methodology of Evolutionary Computing
Authors: Zhuo Jun Fei , Wu Xing He , Wu Guan Zhao , Yao Min
Published: March 2012

Evolutionary computing is one of the important branches in computational intelligence. This paper mainly introduces four new branches of the evolutionary computation, i.e. Gene Expression Programming (GEP), Particle Swarm Optimization (PSO), Differential Evolution (DE) and Estimation of Distribution Algorithms (EDA).
Sensor Array Self-Calibration for Two-Dimensional Direction of Arrival Estimation
Authors: Xiao Da Wei , Cheng Jin Fang , Liu Yi
Published: March 2012

In recent years, high-resolution Direction of Arrival (DOA) estimation with a sensor array has become indispensable for various applications. In actual measurement, however, DOA estimation accuracy is deteriorated by many error factors. For a uniform linear array (ULA), there exist algorithms for self-calibration for single-dimensional (1-D) DOA estimation. In this paper, we develop a simple self-calibration method for two-dimensional (2-D) DOA estimation with an L-shaped array.
Study on MRAC Strategy of Suspension System Based on Magneto-Rheological Fluid Damper
Authors: Gao Yong Qiang , Zhang Jin Qiu , Jia Jin Feng , Yue Jie
Published: March 2012

Magneto-rheological fluid damper(MRFD) is one of new type damper. Based on MRFD, a new model reference adaptive control(MRAC) system is designed in this paper, and it employed sky-hook damping control as model reference. Lyapunov stability theory is used to deduce adaptive control law, and simulation result indicates that MRAC system is not only can follow sky-hook control quickly and well, and it also can adapt to the road conditons, varaition of vehicle body mass and suspension system parameter
Study of Transfer Matrix of Rolling Bearing Including Squeeze Film Damper
Authors: Tang Hua Tao , Wu Xin Yue
Published: March 2012

The transfer matrix of rolling bearing including squeeze film damper (SFD) is studied, and the rotor – bearing system is modeled by transfer matrix method of multi-body system. It is proved by an example that the method, which provides a new idea to solve the problem of complex rotor – bearing system, is feasible and effective.
Study of a New Wavelet Neural Network of Image Compression Simulation
Authors: Zhao Xue Zhang , Qi Qun
Published: March 2012

In the practical need in order to make the most effective image compression in this paper, a new image compression used wavelet neural network model, and gives the corresponding calculation formula and algorithm procedures, By using wavelet transform good time-frequency local area on the characteristics and neural network self-learning function characteristics, overcome traditional BP neural network of hidden-layer points are difficult to be determined and the convergence speed is slow and easy to converge to a local minimum points shortcomings. The results of the simulation experiment prove wavelet neural network image compression characteristic and the convergence speed are much better than traditional BP neural network, and show that the algorithm is effective and feasible.
Study on Improvement of Chain Plate Feeding System
Authors: Li Cheng Qun , Hou Kai Yuan
Published: March 2012

This temple describes the composition and working principle of chain plate feeding system. However, the phenomenon that the chain plate of feeder are often severely wore exists in the process of ore production. In order to solve the problem, the cause that affects their working life is found. On the basis of it, the structure of ore storage is improved and some measures on improvement of chain plate wear are taken.
The Application of a New SEPIC in Photovoltaic System
Authors: Li Cheng Qun , Yang Jin Xiang , Gao Tie Jun
Published: March 2012

The traditional SEPIC converter switch is turned on for a long time and as time is short, resulting in loss and temperature rise is too large, etc, isolated SEPIC converter is proposed to analyze the working principle and the transmission efficiency. And the circuit is improved, designed clamp isolated converters, photovoltaic cells based on the characteristics of the circuit used in photovoltaic power generation MPPT (Maximum Power Point Tracking, referred to as MPPT) system. Simulation and experimental results verify its feasibility.
A Novel Dynamic Real Time Controller Based on Score Function of Intuitionistic Fuzzy Sets with Time Parameter
Authors: Zhang Zhen Hua , Yang Jing Yu , Ye You Pei , Hu Yong , Zhang Qian Sheng
Published: March 2012

In this paper, we first present intuitionistic fuzzy sets with time parameter (IFSTP). Compared with intuitionistic fuzzy set (IFS), IFSTP can provide membership function with time parameter, non-membership function with time parameter, and hesitancy function with time parameter. Thus, IFSTP is more suitable for real-time controller than IFS. Then we propose a type of score function according to IFS and IFSTP. The results of pattern recognition show that the score function method is more effective than conventional distance measure method and similarity measure method. Finally, using the score function of IFSTP, we design a dynamic real time controller, which is more comprehensive and flexible than the intuitionistic fuzzy controller.
The Constraints on the Physical Parameters in Gauge Interactions of Leptons in the Hung Model
Authors: Bu Jian Ping , Jia Bei
Published: March 2012

It is known to all that the right-handed neutrinos can not be produced and detected at present and future colliders in the most popular see-saw scenarios for the simple reason that they are too heavy in these models. However, a simple extension of the Standard Model (SM) particle content [1], including mirror fermions,two triplet and one singlet Higgs fields, leads to a scenario in which the see-saw mechanism [2] is realized with the Majorana mass of the right-handed neutrino being of the order of the electroweak scale or smaller. Motivated by this viewpoint, we have studied the model suggested by Hung recently and given the constraints on the physical parameters in gauge interactions of leptons in this model.
Test Study of the Damage-Fractured Process for Double Fractured Rock
Authors: Wang Guo Yan , Dou Ming Wu , Li Shu Chen
Published: March 2012

Based on the rock mechanics test systems and the monitoring test of the acoustic emission (AE), the damage –fractured process for the double fractured rock is studied in order to gain the characteristics of deformation and damage evolution for the double fractured rock under the uniaxial compression. The damage evolution threshold value and the damage interpretation about the full stress-stain curve are given and the influence of initial damage on rock strength is analyzed. The results provide experimental foundation for engineering application.
The Application of Fuzzy Comprehensive Evaluation Method to the Assessment of Ascension Brake System Reliability
Authors: Qiao Hong Bing , Pang Ao Shuang , Xu Hai Long
Published: March 2012

This paper first introduces fuzzy comprehensive evaluation method to mine machinery. We evaluate the mine elevator braking system's reliability comprehensively from the perspective of the system. Application of the engineering calculation method can prove the reliability of the whole braking system systemically and completely. The precise data of real-time reliability could supply scientific and reliable information directly to hoist staff. The introduction of the method makes up the blank of analysis for elevator braking system safety and reliability, and provides a new thinking for performance evaluation of mining machinery.
The Implementation of Distance Measurement Using Binocular Vision
Authors: Hou Alin , Geng Ying , Cui Xue , Yuan Wen Ju , Shi Feng Guang
Published: March 2012

The method of distance measurement based on binocular stereo vision is presented in this paper. The model of camera imaging is established and the process of camera calibration is described. Interior and external parameters of two cameras are calculated by HALCON. The system of visual measurement is fabricated. The parallax measurement of the image pairs is accomplished. The simulation experiments of distance measurement have been done and the calculated results can be in accordance with the actual distance.
The Method of Selecting the Distance between Holographic Plane and Source Plane in NAH
Authors: Tang Bo , Li Rui Liang , Tang Shuang Xi , Liu Guo Ping , Gao Jie
Published: March 2012

In the near-field acoustic holography, the parameter have an important effect on the reconstruction precision. As to the distance between the holographic plane and the source plane, there are the spatial resolution and the attenuation rule of evanescent wave which need to be considered. As soon as meeting the two demands the reconstruction result represent the sound pressure distribution of source plane. The simulation proves that the method can reduce the error of holographic reconstruction and improve the reconstruction precision.
The Research of the Gun Zone Charge Recognition Technology Based on BP Network
Authors: Xu Dong Sheng , Jia Chang Zhi , Liu Guang Sheng , Zhang Jing Bo
Published: March 2012

The barrel life is decided by explosive payload, tempreture, firing interval, ammunition type and other factors. Thus the zone charge’s auto-recognition is the first question to realize the automatic prediction technology of the barrel life. The zone charge’s recognition technology was proposed based on BP Network. The theory support could be provided by the technology to realize the zone charge’s auto-recognition.
The Inverse Research of Electrical Exploration Results
Authors: Yao Li , Liu Dong Dong , Zhao Yu
Published: March 2012

This paper mainly researches the inverse problems of the electrical exploration results. Through the inverse calculation using genetic algorithm and conjugate gradient method, the model parameters and inverse curves can be obtained. In the paper, the exploration abnormal results of apparent resistivity are inverse analyzed under the anomaly condition of double-pole device of electrical exploration. The inverse results of the model and theoretical analysis are compared. The result indicates that genetic algorithm and conjugate gradient method can be used to obtain the inverse parameters of the exploration results, but the precision of the parameters is different in different geological conditions and methods.
The Safety Disassembling Principle of Ammunition Screw Parts and its Application
Authors: Yang Run Ze , Shi Hua Feng , Zhang Zhi , Ma Yu Feng
Published: March 2012

In the disassembling of ammunition screw parts, the explosion will happen when the ammunition parts heavily damaged by the screw driver. To solve the problem the synchronous backing principle is put forward, which is that the screw driver actively moves backward a screw pitch of the screw part when the screw driver turning a circle. According to the gap between the screw driver and the workpiece, the failure of the disassembly can be identified and the explosion can be prevented. Finally, a structure of the screw driver and the gap detection mechanism designed by the principle is suggested and some application examples are given.
The Study on Robot Control Using Underwater Sensor Network
Authors: Zhou Yang , Huang Wen Kai
Published: March 2012

In this paper, using underwater modems we have designed the reduced size of the robot control message by a matching method. Besides, in order to confirm the operation of the designed protocol, we have implemented the PC control program, the transmitter-receiver modem coding, the robot control protocol matching program as well as made an experiment on accurately controlling the robot via underwater modem in the PC control program. The robot control is well implemented in a test environment. And we can make sure that the modem, developed in our center, guarantees the transmission speed of message for controlling the robot. Besides, through a study on the modem and the control protocol, we could transmit more data than when using the original robot control protocol.
The Study of Fault Diagnosis Method Based on Chaos Characteristics
Authors: Zhang Feng , Pang Xiao Li , Xiong Xiao Yan
Published: March 2012

Based on chaotic characteristics of vibrating screen sides in vertical direction, the paper used phase space reconstruction theory to calculate the characteristic parameters of vibration signals, which are correlation dimension and Lyapunov exponent. Through experimental research, it was found that there was obvious difference in Correlation dimension and Lyapunov exponent when of vibrating screen has crack and has no crack. The characteristic parameters of vibration signals can be used as the basis to determine vibrating screen has crack or no crack. Using this method for fault diagnosis is simple, intuitive, and convenient for analysis.
Travel Time Prediction of Road Network Based on Multi-Source Data Fusion
Authors: Liu Wen Ting
Published: March 2012

This paper is concerned with the task of travel time pre-diction of urban roadway. For improving the travel time predication ac-curacy, a travel time predication model based multi-source data fusion is proposed. The prediction procedure is divided into two phases, the estimation phase and the prediction phase The method is combined the historical traffic patterns with real-time traffic data as a linear. The resulting model is tested with realistic traffic data, and is found to perform well.
VHDL- Based FPGA/CPLD Design Optimization Research
Authors: Pang Xue Min , Yu Dao Jie , Guo Yu Hua , Zhou Chang Lin
Published: March 2012

The optimization of speed and area are the key points which must be put into consideration in FPGA/CPLD optimization design. In this paper, factors which affect the complexity of circuit structure are analyzed. The relationship which is difficult to balance between speed-optimization and area-optimization is also studied. Methods for speed-optimization and area-optimization are given respectively, and some examples in application are provided.
Multipurpose Detecting System for Automotive Switch Function Based on Virtual Instrument (LabVIEW) and Embedded Technology (ARM)
Authors: He Hong , Su Xing , Yang Pei Pei , Li Jian Wen , Shi Shao Hua
Published: March 2012

Contrary to the problem that automobile switches have various kinds and large differences in the structure and performance so that traditional testing methods have been unable to meet the testing requirements of high performance switches, the paper designs a new detection system used to detect the functions of general auto switches which applies the developing environment LabVIEW based on virtual instrument technology and adopts the technology of embedded observe and control system. Using PC as the host computer, the system adopts the LabVIEW8.5 to compile a real-time monitoring system with good human-computer interface; S3C2440-ARM9 processor is used as the main controller of observe and control system in the inferior computer which collects output current signal when the circuit is conducted after switch is pressed. After the coding process of LwIP software protocol and the drive of Ethernet controller DM9000, the signal is transmitted to PC through Ethernet interface. Compared with conventional testing measures, this system greatly improves the real-time performance as well as working efficiency of detecting switch functions and reduces the corresponding human and material resources.
A Wireless Head-Controlled Mouse Design Using Adaptive Unscented Kalman Filter Algorithm
Authors: Gao Tong Yue , Shen Chun Tao , Gong Zhen Bang , Rao Jin Jun , Luo Jun
Published: March 2012

For some disabled people can’t use hand to control the mouse, this paper designs a novel head-controlled mouse. Using accelerometers and gyroscopes as the sensitive element of the system measure the head rotation angle. The mouse is controlled as for the relationship between the head rotation angle and the mouse move distance. For mouse click operation, this article designed a software to achieve. Considering the MEMS sensor noise affect the mouse control accuracy, using the unscented Kalman filter (UKF) to fusion the data of accelerometers and gyroscopes to obtain the optimal angle estimation. Compared with only using an accelerometer or gyroscope sensor, the method proposed in this paper for angle measurement can have high accuracy and stability, thereby improving the mouse control precision and maneuverability.
Design of CAN Central Control Modular Based on USB
Authors: Zhang Xiao Yan , Fan Guo Liang
Published: March 2012

The central control modular of liquid level data acquisition and transmission system based on CAN bus was introduced. The modular was controlled by PC for transmitting and receiving data to CAN units through the USB port by the USB2.0-CAN High Speed adapter card designed by CP2102 and SJAl000, and the CAN bus controller SJA1000 and CP2102 was controlled by single chip computer (SCC) AT89C51. The hardware interface circuits was introduced, and the software flowchart and PC application program was also designed. The result shows that the system has the advantages of strong real-time, high speed, high reliability, easily extending communication devices, Plug and Play supporting, and automatic configuration. Its communications quality is better than the traditional ones, such as RS232, RS485 et al., and it can be used as real-time monitor in industrial multiple devices.
Original Methods for Diffusion Measurements in Polycrystalline Thin Films
Authors: Portavoce Alain , Blum Ivan , Hoummada Khalid , Mangelinck Dominique , Chow Lee , Bernardini Jean
Published: March 2012

With the development of nanotechnologies, the number of industrial processes dealing with the production of nanostructures or nanoobjects is in constant progress (microelectronics, metallurgy). Thus, knowledge of atom mobility and the understanding of atom redistribution in nanoobjects and during their fabrication have become subjects of increasing importance, since they are key parameters to control nanofabrication. Especially, todays materials can be both composed of nanoobjects as clusters or decorated defects, and contain a large number of interfaces as in nanometer-thick film stacking and buried nanowires or nanoislands. Atom redistribution in this type of materials is quite complex due to the combination of different effects, such as composition and stress, and is still not very well known due to experimental issues. For example, it has been shown that atomic transport in nanocrystalline layers can be several orders of magnitude faster than in microcrystalline layers, though the reason for this mobility increase is still under debate. Effective diffusion in nanocrystalline layers is expected to be highly dependent on interface and grain boundary (GB) diffusion, as well as triple junction diffusion. However, experimental measurements of diffusion coefficients in nanograins, nanograin boundaries, triple junctions, and interfaces, as well as investigations concerning diffusion mechanisms, and defect formation and mobility in these different diffusion paths are today still needed, in order to give a complete picture of nanodiffusion and nanosize effects upon atom transport. In this paper, we present recent studies dealing with diffusion in nanocrystalline materials using original simulations combined with usual 1D composition profile measurements, or using the particular abilities of atom probe tomography (APT) to experimentally characterize interfaces. We present techniques allowing for the simultaneous measurement of grain and GB diffusion coefficients in polycrystals, as well as the measurement of nanograin lattice diffusion and triple junction diffusion. We also show that laser-assisted APT microscopy is the ideal tool to study interface diffusion and nanodiffusion in nanostructures, since it allows the determination of 1D, 2D and 3D atomic distributions that can be analyzed using diffusion analytical solutions or numerical simulation.
Influence of Deformation on Precipitation Kinetics in Mg-Tb Alloy
Authors: Melikhova Oksana , Čížek Jakub , Hruška Petr , Vlček Marián , Procházka Ivan , Vlach Martin , Stulíková Ivana , Smola Bohumil , Žaludová Naďa , Islamgaliev Rinat K.
Published: March 2012

Precipitation effects in age-hardenable Mg-13wt.%Tb alloy were investigated in this work. The solution treated alloy was subjected to isochronal annealing and decomposition of the supersaturated solid solution was investigated by positron annihilation spectroscopy combined with transmission electron microscopy, electrical resistometry, differential scanning calorimetry and microhardness measurements. Peak hardening was observed at 200°C due to precipitation of finely dispersed particles of β phase with the D019structure. Vacancy-like defects associated with β phase particles were detected by positron annihilation. At higher temperatures precipitation of β and subsequently β phase takes place. Formation of these phases lead to some additional hardening and introduces open volume defects at precipitate/matrix interfaces. To elucidate the effect of plastic deformation on the precipitation sequence we studied also a Mg-13wt.%Tb alloy with ultra fine grained structure prepared by high pressure torsion. In the ultra fine grained alloy precipitation of the β phase occurs at lower temperature compared to the coarse grained material and the peak hardening is shifted to a lower temperature as well. This effect can be explained by enhanced diffusivity of Mg and Tb atoms due to a dense network of grain boundaries and high density of dislocations introduced by severe plastic deformation. Moreover, dislocations and grain boundaries serve also as nucleation sites for precipitates. Hence, precipitation effects are accelerated in the alloy subjected to severe plastic deformation.
Duplex Stainless Steels: A Dozen of Significant Phase Transformations
Authors: Padilha Angelo Fernando , Aguiar D.J.M. , Plaut R.L.
Published: March 2012

During processing or use, duplex stainless steels are subject to a great number of significant phase transformations, such as solidification, partial ferrite transformation to austenite, ferrite eutectoid decomposition to sigma phase plus austenite, chi phase precipitation, chromium carbide precipitation, chromium nitride precipitation, ferrite spinodal decomposition, phase dissolution during solution annealing, forming of two types (epsilon and alpha prime) of strain induced martensite, martensite reversion to austenite, ferrite and austenite recrystallization. This paper summarizes the phase transformations that occur (individually or combined) in duplex stainless steels and presents some new results.
Textured Ti3SiC2 by EPD in a Strong Magnetic Field
Authors: Mishra Mrinalini , Sakka Yoshio , Hu Chun Feng , Suzuki Tohru , Uchikoshi Tetsuo , Besra Laxmidhar
Published: March 2012

We present a method for fabrication of textured MAX phase ceramics, particularly, Ti3SiC2; by EPD in a strong magnetic field (12T). Ti3SiC2was dispersed in cationic polyelectrolyte-Polyethylenimine (PEI). Addition of 0.3-1dwb PEI resulted in high zeta potential values and suspension was found to be stable and of good fluidity. The optimized suspension parameters for EPD were determined as 10vol% Ti3SiC2and 1dwb PEI in 50 % ethanolic water at pH ~ 7. X-ray diffraction analysis of the textured samples revealed that the preferred orientation of Ti3SiC2grains parallel to the magnetic eld direction was along the a,b-axis. The Lotgering orientation factors on the textured top surface and textured side surface were determined asf(hk0)= 0.35 andf(00l)= 0.75, respectively.
Electrophoretic Fabrication of Rechargeable Micro Lithium-Ion Battery with 3D Configuration
Authors: Munakata Hirokazu , Kaido Hiroya , Yoshima Kazuomi , Kanamura Kiyoshi
Published: March 2012

A polymer wall was developed between interdigitated comb-type current collectors on a SiO2/Si substrate as the support for three-dimensionally (3D) accurate deposition of electrode materials by electrophoretic deposition (EPD) method. As anode and cathode materials, Li4Ti5O12and LiCoO2with a particle size of ~ 200 nm were synthesized, respectively, and their dispersibility in the suspensions including Ketjen Black and poly (vinylidene fluoride) was investigated. Consequently,N-methylpyrrolidone provided their good suspensions, and an electrode aspect ratio of 1:1, which can provide a high capacity and good rate performance to micro lithium-ion batteries, was successfully achieved in both Li4Ti5O12composite anode and LiCoO2composite cathode.
Pulse Electric Fields for EPD of Thermal Barrier Coatings
Authors: McCrabb Heather , Kell Joseph , Kumar Binod
Published: March 2012

Conventional electrophoretic deposition is being combined with pulse electric fields to deposit yttria stabilized zirconia from ethanol based suspensions onto bondcoated turbine alloys for thermal barrier coatings. The addition of the pulse electric fields to the electrophoretic process has demonstrated the capability to decrease the coating roughness, minimize hydrolysis, and decrease coating edge effects commonly encountered in electrokinetic and electrochemical deposition processes. Subsequent to the electrophoretic deposition process the green body coatings were subjected to a combined binder burnout and sintering process for further coating densification. The coatings have been qualified in terms of surface roughness as well as microstructure and experiments have been performed to show that the pulse EPD process can deposit TBC materials onto turbine components.
Fundamentals of Pulsed and Direct Current Electrophoretic Infiltration Kinetics
Authors: Palmer Timothy R. , Buie Cullen R.
Published: March 2012

The present research endeavors to demonstrate the applicability of electrophoretic deposition (EPD) for the infiltration and coating of porous materials to create advanced composites. Motivated by improved materials requirements of tokamak fusion reactors, the composites are created by depositing ceramic nanoparticles in porous metallic matrices using both constant voltage and pulsed DC EPD. Silicon dioxide particles with a nominal diameter of 20 nm are used as inexpensive surrogates for more application-appropriate boron carbide due to their similar surface chemistry. Fabricated materials are characterized using scanning electron microscopy (SEM) and energetic dispersive x-ray spectrometry (EDX) to visualize coating quality and penetration of the material into the substrate. At low voltage, the deposited mass in constant voltage EPD increases linearly with time while at high voltage it asymptotically approaches a maximum yield of 1.988 grams. Pulsed EPD experiments demonstrate a reduction in deposition yield but also elimination of macro-pore generation in the low voltage case. A non-dimensional parameter, ξ*, relating electrokinetics and diffusion is derived which improves process design for pulsed EPD systems.
AFM Characterization of the Nanoparticles Arrangement by Electrophoretic Deposition
Authors: Escribano J.A. , Gonzalo-Juan Isabel , Sanchez-Herencia Antonio Javier , Ferrari Begoña
Published: March 2012

In this study, coatings with irregular nanotopography prepared by electrophoretic deposition (EPD) in electro-polished surfaces are characterized. Films are composed by Yttria Stabilized Zirconia (YSZ) particles, 5-8 nm in size and spherical morphology, synthesized under hydrothermal conditions and re-dispersed in the post reaction medium. Growth behaviour of coatings with time, including array morphology, aggregation origin and activity, are explored by means of atomic force microscopy (AFM) and its different measurement modes. Arrangement of electrically driven particles at the nanoscale can be assessed through the topographic description of films prepared with increasing deposition times. Moreover, topography can be associated to the electrokinetic behaviour of particles and agglomeration degree of the suspension. The evaluation of particle junctions and then the quality of particle cohesion within the film can also be discerned by AFM characterization.
Electrophoretic Deposition of Cadmium Sulfide Nanoparticles: Electric Field and Particle Size Effects
Authors: López Israel , Vázquez Alejandro , Gómez Idalia
Published: March 2012

The present work shows the electric field and particle size effects on the formation of nanostructured arrays by electrophoretic deposition of cadmium sulfide (CdS) nanoparticles. The CdS nanoparticles with mean diameter below 6 nm were prepared by a microwave assisted synthesis. These nanoparticles were aged for one and two weeks at room temperature in order to produce nanoparticle agglomeration. The CdS nanoparticles were deposited on aluminum plates, with 1 cm of distance between them, using a constant applied voltage of 600 and 900 mV for 1 min. The nanostructures formed using CdS nanoparticles freshly prepared under 900 mV show spherical morphology. Under a voltage of 600 mV, nanostructures with elongated morphology were obtained.
A Procedure Based on Magnetic Induction to Evaluate the Effect of Plastic Deformation by Multiaxial Stresses on TRIP Steels
Authors: Miguel-Eguía Valentin , Avellaneda F.J. , Coello Juana , Martínez Alberto , Calatayud Antonio
Published: March 2012

As it is well-known, TRIP 800 steels modify their structure with the deformation grade. So, part of the retained austenite turns into martensite by plastic deformation. The usual techniques tried out to evaluate this transformation whether do not lead to obtain good results or the experimentation with them is very complex. In this work, a magnetic induction method is experimented and developed in order to determine the evolution of a TRIP 800 steel microstructure with the strain grade. The variables that can have influence on this kind of analysis methodology have been studied and their effects evaluated. This method has been applied to determine the induced martensite by deformation under conditions of pure shear deformation. Results point that this method allows to state that the microstructure evolution taking place in TRIP 800 steels is not proportional to the strain applied.
Geometry Modelling of Clads Generated by Laser Cladding
Authors: Tabernero I. , Lamikiz Aitzol , Ukar Eneko , Martínez S.
Published: March 2012

The laser cladding process is based on the generation of a melt-pool in a substrate where a filler material is injected, generating a high quality clad with a minimum heat affected zone. This process is industrially used to generate coatings over wear or damaged surfaces, being an alternative to traditional deposition techniques. One of the most important aspects for its industrial application is to know the clad geometry in order to calculate the deposited layer thickness. This work presents a model in which, starting from the concentration of injected material and the melt-pool geometry, clad height is finally estimated. Both input variables are obtained by two previous validated models. On one hand, the melt pool is estimated by a thermal model based on the finite difference method, and on the other hand, concentration of injected material is provided by a particle concentration CFD model. This data is used in a mass balance over melt-pool area in order to estimate the deposited clad height.
Near Grain Boundary Behavior of Aluminum Bicrystals Deformed in Plane Strain Conditions
Authors: Wajda Wojciech , Paul Henryk
Published: March 2012

The paper describes the mechanism of deformation at 77 K of pure aluminum bicrystals of different grain orientations. The following orientations were selected: {100}/{110} (cube/Goss) and - {100}/{100} (cube/shear) to represent the unstable vs. stable and the unstable vs. unstable behaviours, respectively. The bicrystalline samples were deformed in the plane strain conditions with the use of a channel-die immersed inside a reservoir with liquid nitrogen. The low temperature deformation increases the tendency to form plain strain inhomogeneities of the deformation in the grains with an unstable orientation. In both sets of crystallite compositions, the grain boundary was situated perpendicularly to the compression plane. A particular interest was paid to the analysis of the tendencies of the crystal lattice rotations near the grain boundary and the description of the deformation behaviour of the material in the macro- scale (hardening behaviour). A detailed analysis of the crystal lattice rotations was possible with the application of the local orientation measurements by means of scanning and transmission electron microscopes, equipped with the electron backscattered diffraction and convergent beam electron diffraction facility, respectively. The experimental results of the local orientation measurements were used to evaluate the accuracy of the numerical prediction of the macro-scale behaviour of bi-crystalline samples by a single Cristal Plasticity Model. The investigation shows that the crystallites behave essentially as single crystals in the same deformation conditions. Due to the similar hardening behaviour of the investigated crystallites (similar values of the Taylor factors) the grain boundary remains unchanged. The calculated lattice rotations are similar to those observed experimentally. Key words: aluminium bi-crystals, texture, microstructure, single crystal plasticity model
Degradation of Microstructure after Service in ZhS6k Superalloy with Diffusive Aluminide Coating
Authors: Sozańska Maria , Chmiela Bartosz , Kianicova Marta , Cwajna Jan
Published: March 2012

This paper presents the degradation of hollow turbine blades made of ZhS6K nickel-based superalloy after service in DV2 aero engines. The blades were coated with a diffusive aluminide coating (Al-Si) to improve the oxidation and hot corrosion resistance. Turbine blades work under extreme conditions and a complex state of stress. During service, creep and fatigue of various natures take place. The interaction among hot combustion gases causes oxidation of the surface layer and hot corrosion and micro cracking of the coating. Moreover, changes in morphology of the γ’ phase just under the coating and transformations of the primary carbides take place. The factors limiting the lifetime of turbine blades are the quality of the aluminide coating andmicrostructure of the superalloy, depending on the service parameters—the temperature and the duration of service. It was found that exposure to high temperatures above the critical value for several seconds substantially decreased the engine power and its durability. In this paper, analysis of the microstructure, chemical composition and phase composition of the turbine blades after service were carried out. Evaluation of the extent of degradation was performed using the scanning electron microscopy (SEM), energy dispersive X-ray microanalysis (EDS) and electron backscatter diffraction (EBSD) techniques. The EBSD technique was used to analyse the phase composition in micro areas, especially to identify carbides before and after transformations.
TEM Investigations of Damage Caused by Indentation of Multilayer TiN/Ti/a-C-H Coatings
Authors: Major Łukasz
Published: March 2012

The effect of damage on microstructure of multilayer coatings (TiN/Ti/a-C:H) have been analyzed. They were deposited through Pulsed Laser Deposition technique (PLD). The coatings microstructure was characterized using TECNAI F20 (200kV) FEG. The phase and chemical composition were described by EDS (Energy Dispersive X-Ray Spectroscopy) and electron diffraction patterns respectively. Coatings damage resistance was tested by pushing diamond ball with 1N of the applied load (static test). Thin foils were prepared directly from the wear track by focused ion beam method (FIB) using QUANTA 200 3D DualBeam. The multilayer coatings were characterized by strongly dislocated microstructure in TiN layers (like in single layered TiN), while a-C:H were amorphous. After mechanical test the multilayer TiN/Ti/a-C:H coating was strongly deformed. Ceramic TiN and a-C:H layers showed brittle cracking, while very thin metallic Ti layers (presented at each interface) deformed plastically. Deformation lines were propagating in 450 to crystalline growth direction. The wear of crystalline TiN layers caused cracks along {111} planes. The presence of metallic phase lead to the cracking resistance properties increase and the increase an energetic cost of propagating cracks.
TEM Investigation of Metal/Ceramic Interfaces in AA7475/AlN or Al2O3 Nano-Composites
Authors: Gajewska Marta , Dutkiewicz Jan , Lityńska-Dobrzyńska Lidia , Morgiel Jerzy
Published: March 2012

Microstructure of two types of 7475 aluminum alloy matrix composites with additions of 10 wt.% and 20 wt.% of Al2O3 or AlN were investigated. Pre-alloyed 7475 aluminum powders were mixed with ceramic particles and milled in a high energy planetary Fritsch ball mill for up to 40h. Subsequently, it was compacted at 380°C/600 MPa. The microstructure of the obtained composites was studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The performed investigations proved that both types of composites show a good dispersion of ceramic phases. The composite matrix was characterized by fine grain size, i.e. less than 100 nm and contained a high density of even smaller, Zn, Cu or Fe rich precipitates. The EDS chemical analysis indicated local presence of MgO at the metal/ceramic interfaces in both types of composites. The presented approach allowed to produce a composite with AlN or Al2O3 particles in nano-crystalline aluminium alloy matrix.
Microstructure, Chemistry and Mechanical Properties of the Ni/AgBiCuSn/Ni Interconnections
Authors: Sypień Anna , Lityńska-Dobrzyńska Lidia , Wierzbicka-Miernik Anna , Zieba Pawel
Published: March 2012

The paper presents results of electron microscopy studies on the microstructure, chemical composition and mechanical properties of the Ni/AgBiCuSn/Ni interconnections obtained due to the conventional soldering. The scanning (SEM) and (TEM) transmission electron microscopy combined with an energy dispersive X-ray spectroscopy allowed to reveal the presence of two intermetallic phases (Ag3Sn and Cu6Sn5) in the whole interconnection area for all the applied solders and soldering times. In the vicinity of Ni substrate both phases were modified with Ni (2-4.5 %at.). Some of Ag3Sn precipitates took the elongated shape and they were located across whole interconnection width. The SEM examination after shear test showed that the joints ruptured in a ductile manner, as manifested by the dimples present on the fracture surfaces. The dimples prove also that the plastic deformation occurred along the loading direction.
Morphology and Chemical Composition of Ag/In/Ag Interconnections
Authors: Skrzyniarz Przemyslaw , Lityńska-Dobrzyńska Lidia , Zieba Pawel
Published: March 2012

One of the environment protection’s main aims is working out soldering materials able to replace the Sn-Pb solders commonly used so far. The joint obtained using diffusion soldering fulfills these conditions and takes up 6 times less space than in the case of conventional soldering. Moreover, it can work at the temperatures higher than 350 [°C] and it often shows mechanical and thermal stability at temperatures 2-3 times higher than the joining temperature. This paper presents the morphology and chemical composition Ag/In/Ag joint diffusion-soldered at 193 [°C] for 1.5 and 2 hours. Two intermetallic phases, namely AgIn2 and Ag2In were identified within the joint using an energy dispersive X-ray microanalysis and selected area electron diffraction techniques. Most probably the AgIn2 phase was formed during cooling of the joints from the soldering temperature because its melting point is 166 [°C]. On the other hand, the Ag2In phase is desired as its thermal stability is over 300 [°C]. This phase grows into the solder material (In) relatively fast. The exponential factor n determined from the appropriate kinetic equation was found to be 0.41, which suggests some contribution of the grain boundary diffusion process in addition to the volume diffusion (n=0.5).