bluuebunny/crossref_metadata_2025 huggingface dataset:
Tibetan-Chinese Named Entity Extraction Based on Comparable Corpus
Authors: Sun Yuan , Zhao Qian
Published: June 2014

Tibetan-Chinese named entity extraction is the foundation of cross language information processing, and provides a basis for machine translation and cross language information retrieval research. In this paper, we use the multi-language links of Wikipedia to obtain Tibetan-Chinese comparable corpus, and combine sentence length, word matching and entity boundary words together to get parallel sentence. Then we extract Tibetan-Chinese named entity from the comparable corpus in three ways: (1) Extracting Natural labeling information. (2) Acquiring the links of Tibetan entries and Chinese entries. (3) Using sequence intersection method, which includes the sentence representation, Chinese named entity recognition and corresponding Tibetan sentences intersection. Finally, the results show the extraction method based on comparable corpus is effective.
The Application of Iteration Learning Control in Silkworm Incubation Chamber System
Authors: Zhang Yin Jun
Published: June 2014

Silkworm egg incubation is a very complicated process and is hard to establish the mathematical model. In order to improve the temperature and humidity of silkworm incubation chamber control method, the paper deal with the method of iteration learning control looking for expected input. Based on the summary of human experience, designing learning rule is given. The simulation result shows iterative learning control has ideal tracking control.
Research on MapReduce Task Dynamic Balancing Strategy Based on File Label
Authors: Huang Rong , Xiong An Ping , Zou Yang
Published: June 2014

MapReduce is one of the core framework of Hadoop, it’s computing performance has been widely concerned and researched. In heterogeneous environment, unreasonable map task assignments and inefficient resource utilization lead to multiple backup tasks and the job total execution time is poor.For these problems, this paper proposes a new map task assignment strategy, which is map task dynamic balancing strategy based on file label. The strategy marks on job according to the different types, estimates node computing capabilities and historical processing efficiency of each label task, ensures map task which was assigned can execute successfully. Experiments show that, the strategy can effectively reduce number of backup tasks in map phase, and to some extent optimize the total execution time of the job.
Fault Diagnoses Using Inverse Fuzzy Model
Authors: Zheng Hui Jun , Fu Qiao
Published: June 2014

This paper investigates a new method of fault diagnoses and reliability analysis based on inverse fuzzy model method. The proposed method employs inverse fuzzy model solving method to estimate the component state based on the measured system performance and relationship about component state and system performance which is constructed by expert. The method is proved to be effective in fault diagnoses.
A Hybrid IGA-SA Algorithm for Optimization Problems in Fault Diagnosis
Authors: Li Xiao Quan , Lin Mao , Liu Shuai
Published: June 2014

This paper presents a hybrid algorithm combining immune genetic algorithm (IGA) with simulated annealing (SA) to overcome the shortages of both the two algorithms respectively. SA is introduced to solve the problem of IGA in fault diagnosis, unable to reach whole convergence and etc. by designing a new kind of self-adaption strategy of genetic parameters. Finally, the Schaffer function is introduced to show the optimization ability of this proposed IGA-SA algorithm.
Efficient Particle Swarm Optimization Algorithm Based on Affinity Propagation
Authors: Su Lin Ping , Wang Zhao , Huang Zheng Guan , Li Hao
Published: June 2014

Since the 1950s, with the great development of computer technology and bionics, particle swarm optimization (PSO) was raised. The particle swarm optimization mimics the nature biological group behaviors, and has the following advantages compared to classic optimization algorithms: it is a global optimization process and doesn’t depend on the initial state; it can be applied widely without prior knowledge on the optimization problems; the ideas and the implements of PSO are quite simple, the steps are standardization, and it’s very convenient to integrate it with other algorithms; PSO is based on the swarm intelligence theory, and it has very good potential parallelism. Particle swarm optimization has a feature that fitness value is used to exchange information in the population, and guides the population to close the optimal solution. Therefore, a mount of fitness should be calculated in swarm intelligence optimization algorithms in order to find the optimal solution or an approximate one. However, when the calculation of the fitness is quite complex, the time cost of this kind of algorithms will be too large. What’s more, the fitness of optimization problems in the real world is often difficult to calculate. Addressing this problem,Efficient Particle Swarm Optimization Algorithm Based on Affinity Propagation (EAPSO) is proposed in this paper.
Multi-Thread Memory Particle Swarm Optimization for Dynamic Optimization Problems
Authors: Chen Li , Liu Ju Ming , Ouyang Jun Mei
Published: June 2014

This paper proposes a multi-thread-memory particle swarm optimization (MTM-PSO) for dynamic optimization problems (DOPs). It introduces multi-thread memory to multi-swarm approaches to deal with DOPs. External memory and multi-swarm approaches are adopted. The best particles near the peaks in each environment are saved in the memory according to storage strategy of update and implement. Multi-thread memory makes full use of local and global optima found in each environment. It makes the good information in the previous evolution transfer to the current population adequately. Using the multi-thread memory and its storage strategy, the particles in the memory are always the best information of local and global optima found until in the current envionment. The information will benefit the future evolution. Experiments on the moving peak benchmark (MPB) for different numbers of peaks testiy MTM-PSO has better performance than dynamic optimization algorithms only with multi-swarm approach.
Short-Term Prediction of Ship Motion Based on EMD-SVM
Authors: Liu Sun Bo , Shi Ping An , Wu Lei
Published: June 2014

Ship sailing at sea is affected by many factors, such as winds, waves and so on, which makes six degrees of freedom motions and thus influences the shipboard arms control, aircraft landing and other operations. In view of the non-linear and non-stationary features of ship motion in waves, a new method based on EMD (Empirical Model Decomposition) and SVM (Support Vector Machine) is presented to predict the ship motion. The EMD is used to decompose the ship motion time series data into several IMFs (intrinsic mode functions) and a residual trend term, which decreases the difficulty of prediction. As the IMF is relatively stationary, but also non-linear, these features are fit to be processed by using SVM. Then the decompositions are used as inputs into SVM to forecast ship motion. The simulation and comparison analysis show that the EMD-SVM prediction model can effectively forecast the ship motion in waves.
Tibetan Information Retrieval Technology Integrated with Morphological and Syntactic Cues
Authors: Wan Fu Cheng , Ma Ning , He Xiang Zhen
Published: June 2014

We propose a model of Tibetan information retrieval technology integrated with morphological and syntactic cues, for the aiming to solve the problem of which user search information through the Internet more difficultly, response time of interne is not enough.
Design of a Two-Wheel Self-Balanced Vehicle System
Authors: Zhou Mu Dan , Lin Zhi Da , Lin Zhi
Published: June 2014

This paper introduces a design scheme of two-wheel self-balanced Intelligent Vehicle System. In hardware system, MCU module, angle detection module, motor drive module, laser path detection module, motor speed detection module, power modules and debugging modules are designed. Combined with PWM technology and PID control, speed of two DC motor is controlled, the dynamic self-balanced and fast tracking of the vehicle can be achieved well. The vehicle can be used as an experimental platform of automatic control system, and the feasibility and effectiveness of various control algorithms can be verified.
A Dirichlet-Neumann Alternating Algorithm Using Elliptical Arc Artificial Boundary for Exterior Problems with a Concave Angle
Authors: Chen Ya Jun , Du Qi Kui
Published: June 2014

In this paper, a Dirichlet-Neumann alternating algorithm using elliptical arc artificial boundary for boundary value problem of Poisson equation in an infinite domain with a concave angle is investigated. The convergence of the algorithm is given. The choice of the relaxation factor is discussed. Finally, some numerical examples are presented to show effectiveness of our method.
Fuzzy Comprehensive Evaluation Method of Experimental Teaching Quality Based on AHP
Authors: Li Shan , Rao Hong , Dai Lu Jiang
Published: June 2014

There is no standard and sophisticated experimental teaching evaluation system in university currently even experimental teaching is an important part of practice teaching, which results in lacking of standardization and systematization during experimental teaching. Directing to the problems, this paper constructed an experimental teaching evaluation index system and proposed an evaluation method based on AHP(analytic hierarchy process) and fuzzy mathematical evaluation method, which calculates the corresponding weights for each index and evaluates teaching effectiveness using the fuzzy comprehensive evaluation method and comes to the evaluation results, finally this method was applied to evaluate the experimental teaching process in university fundamental computer course, which showed the validity and reliability of the evaluation system.
An Advanced ECC Dynamic Password-Based Remote Authentication Scheme for Cloud Computing
Authors: Cao Lai Cheng , Han Wei
Published: June 2014

Due to the strong capacity of computing and storage, more and more hackers choose to attack cloud systems for their own use to obtain illegal benefits. In order to prevent the occurrence of this phenomenon, when a cloud user enters into the cloud system, their identity must be verified to protect the security of cloud platform and the interests of legitimate users. Then, we propose a new ECC dynamic password-based authentication scheme for cloud computing in this paper. The proposed scheme provides mutual authentication and identity management. A user also can change his/her password whenever demanded. Furthermore, the scheme has the resistance to possible attacks in cloud computing.
Class Association Rule Mining Based on Incremental Construction of Lattice
Authors: Zhai Yue , Yu Xi , Deng An Sheng
Published: June 2014

In the problem of mining classification rules, previous methods are too general or too over-fitting for a given dataset. In this paper, through analyzing the characteristics of concept lattice and indiscernible matrix, classification rule acquisition based on lattice was proposed. Our method includes two phase: (1) proposing incremental generating the nodes of lattice using indiscernible matrix. (2) Developing some theorems for pruning redundant rules quickly. It is shown by experimental results that our approach not only results in shorter execution times, but also avoids missing important rules than the generalization of previous known methods.
A Network Selection Algorithm Based on Traffic Flow
Authors: Tao Yang , Jiang Yan Li
Published: June 2014

The existing network selection algorithm generally considering the QoS needs of all services which carried by the terminal. Then selecting an optimal network to access to achieve the overall best of all services, However, for each individual service is not necessarily optimal. To solve the problem above, On the basis of multi-mode terminal and multi- parallel transmission of data, we propose a traffic-based network access selection algorithm, which was designed to realize independent network selection for each traffic flow by considering the network congestion and the transmission of high priority traffic and achieve adaptively network access which making the traffic efficient and reliable transmission, By which each network can be fully utilized. The Simulation results demonstrate that the algorithm can reduce the times of network selection and improve the transmission efficiency and the utilization of network. The results suggest that this kind of network algorithm is effective.
Multi-Level Complex Network Control System Based on Cloud Services Platform
Authors: Li Bin Yong , Sun Lin Fu , Tian Ran
Published: June 2014

Aiming at the access control problem of the cloud service platform, puts forward the control scheme of multi-level system for multi type coordination.By the definition of cloud services platform multi access control object system,constructs multidimensional Boolean relation matrix. The semantic relation of Boolean matrices, design of large-scale complex network node control system model, and simulate the hierarchical network loop control model.Through the analysis of network model, shows that the research results can better support for cloud services platform in multi-level access, dynamic authorization complexity problems in management control.
An Audio Hiding Algorithm Based on Spline Interpolation and Wavelet Transform
Authors: Li Jian Yong , Yang Yan Qiu , Yang Bo
Published: June 2014

Based on the characteristics of sampling points to get approximate numerical interpolation point, first to the whole speech signal wavelet decomposition, the extract is not sensitive to the human ear hearing wavelet coefficients as the location of the embedded watermark information, the interpolation factor by using spline interpolation to replace known the low-frequency wavelet coefficients to embed watermark. The simulation results show that the algorithm not only has imperceptibility, such as MP3 compression, low-pass filtering, white noise, sampling, quantitative attack has good robustness. It achieves a better balance in robustness and imperceptibility.
A Pattern Matching Algorithm for Double-Type Characters
Authors: Zhou Hai Yan
Published: June 2014

A fast and efficient matching algorithm is proposed to address the issue on multi-pattern matching of double-byte string, for example Chinese characters, which has major difference with single-byte string matching algorithm. The algorithm capitalizes on double cross link data list and two finite prefix automata to match a double-byte character, so as to solve the storage expansion problems in which the double-byte cross data link table results. The method requires less storage in comparison with double-byte cross data link table, and has the same order of magnitude in efficiency as a single-byte cross-link table approach.
Using Time Reachability Tree Logic to Specifying and Verifying Temporal Behavior of Workflow-Net
Authors: Chen Chyun Chyi , Huang Yueh Min
Published: June 2014

Workflow management has been a hot issue in both academic and industrial research. Deadline assignment is of great significance in workflow management. In order to avoid deadline violation, this paper presents an approach to the schedulability analysis of workflow system modeled in p-time Petri nets by separating timing properties from other behavior properties. The analysis of behavioral properties is conducted based on the reachability graph of the underlying p-Time Petri net, whereas timing constraints are checked in term of absolute and relative firing domains. Our technique is based on a concept called clock-stamped state class (CS-class) and temporal logic. With the reachability graph generated based on CS-class, we can directly compute the end-to-end time delay in workflow execution. We have identified a class of well-structured p-time Petri nets such that their reachability can be easy analyzed and temporal behavior can be easy analyzed by time reachability tree logical.
A Tag-Based Signature Scheme with Shorter Signature Length
Authors: Lu Xiu Hua , Fang Jie
Published: June 2014

Florian Böhl et al. introduced tag-based signature schemes in 2013. We focus on their SIS-based tag-based signature scheme in lattice-based cryptography. Without aggregation techniques in lattice-based signatures, their tag-based signature has long signature length. We use the technique of lattice basis delegation with fixed dimension to shorten the signature length. Compared with the original scheme, our scheme’s signature is one-half length, at the price of security proof in the random oracle model.
DRCH: A Method for 3D Convex Hull
Authors: Huang Xiu Xun , Zhou Ji Ting , Ling Chen , Zhang Wen Jun
Published: June 2014

A novel three-dimensional (3D) convex hull method is proposed, which is called dimensionality reduction convex hull method (DRCH).Through having 3d point set map to 2d plane, most initial 3D points in the convex hull are removed. Then, the remaining points are to generate 3D convex hull using any convex hull algorithm. The experiment demonstrates 3D DRCH is faster than general 3D convex hull algorithms. Its time complexity is O(r log r), where r is the number of points not in the hull. And DRCH can be generalized to higher-dimensional problems.
Rock Image Pore Identification Based on Fuzzy C-Means Clustering and Neural Networks
Authors: Qin Qiu Ju , Qiang Xin Jian , Liu Ye , Yang Jing
Published: June 2014

In order to realize the recognition automation of rock section pore images, a method combined Fuzzy C-Means clustering with BP neural network is proposed to recognize the pore of rock images. Firstly, Fuzzy C-Means clustering as segmentation algorithm are applied to the rock images and they are divided into two types, then using the BP neural network training and classification recognition. It is shown that the trained BP neural network can accurately identify the effective porosity in the casting image, and lay a good foundation for practical applications.
An Electronic Image Stabilizition Algorithm Based on Gray Projection and Circle Projection Matching
Authors: Wang Hui , Sun Peng , Han Xiao Wei
Published: June 2014

In most video systems,the carrier of camera expierences all kinds of motions which make the video ambiguous and unstable.Usually,the gray projection matching algorithm can only stabilize the translation motion between frames,but the rotation motion of frames in a video sequence.By zoning the image into few small regions,the rotation motion could be ignored,then, local movement vector is aqcuired by the grey projection matching method and compensate the movement between frames.Then for the rotation movement,it can be stabilized by the compensation with circle projection matching.
Disparity Estimation of 3-D Mesh for Stereo Video Coding
Authors: Zheng Jia Li , Qin Tuan Fa , Wei Dong Xue , Huang Qin Huan , Deng Lin
Published: June 2014

This paper proposed a disparity estimation method based on the three-dimensional (3-D) mesh model. The disparity estimation is a key step in stereo video coding. By employing intermediate view synthesis, the proposed technique simulate the nodals in the 3-D sureface of stereo image efficiently. Simulated results show that the proposed technique yields a visually more accurate prediciton than the block-matching algorithm.
Integrity and Fidelity Evaluation of Digital Evidence in Live Forensics
Authors: Wang Lian Hai , Xu Qiu Liang
Published: June 2014

The integrity and fidelity of digital evidence are very important in live forensics. Previous research has studied the uncertainty of live forensics based on different memory snapshots. However, this kind of method is not effective in practice. In fact, memory images are usually acquired by using forensics tools instead of using snapshots. Therefore, the integrity and fidelity of live evidence should be evaluated during the acquisition process. In this paper, we give a new viewpoint that memory acquisition can be regarded as a measurement of memory data. From this viewpoint, we evaluate the integrity and fidelity of live evidence in the process of physical memory acquisition. Firstly, several definitions about memory acquisition measure error are introduced to describe the trusty. Then, we analyze the experimental error and propose some suggestions on how to reduce it. A novel method is also developed to calculate the system error in detail. The results of a case study on Windows 7 and VMware virtual machine show that the experimental error has good accuracy and precision, which demonstrate the efficacy of the proposed reducing methods. The system error is also evaluated, that is, it accounts for the whole error from 30% to 50%. Last, a method is proposed to calculate changes or error of system process.
Analysis of Scattering Characteristics for 1D Electromagnetic Wave by Sudden Creation of a Plasma Slab Based on FDTD
Authors: Xu Hong Lei , Ren Yun , Yang Li Xia
Published: June 2014

Based on Maxwell's equations and the time-varying plasma constitutive equation, electromagnetic scattering characteristics by a sudden-created plasma slab can be analyzed. According to one-dimensional numerical analysis, a modified NPML(M-NPML) absorbing boundary condition (ABC), by which the transient plasma can be truncated, was validated. The frequency drift phenomenon for electromagnetic wave in a transient plasma slab and some other useful conclusions are obtained.
Design of Knowledge Reasoning Based Infrared Imagery Fault Detection System for Substation Equipments
Authors: Yuan Qing , Qi Yin Cheng
Published: June 2014

A knowledge reasoning based on-line infrared image monitoring system of the power equipments in substation is designed. The function, feature and structure of the system are introduced. Compare with the usual on-line infrared imaging monitoring system, a knowledge base is added and a knowledge reasoning method is used to diagnose the fault mode of operating equipments. The representation method of knowledge and processing of knowledge reasoning engine are introduced. Our research demonstrates that fault can be diagnosed correctly.
Modeling Hydraulic Power System with Surge Tank
Authors: Kong Fan Nie
Published: June 2014

Based on actual hydraulic structure, the linear and nonlinear hydro power system model with surge tank was established for the first time. The simulation results of model demonstrate that the linear model with surge tank and that of individual penstock exists essential difference. The step response of individual penstock model is monotonic rising up to stable state, but that of model with surge tank is vibrating badly. The nonlinear model with surge tank is dynamic stable.
Optimization Design of Photovoltaic System MPPT Controller
Authors: Liu Ping , Diao Wan Yu
Published: June 2014

By employing INC algorithm based on power estimates and variable step ,the MPPT controller can optimize the judgement if the PV cell can reach the MPP, using the comparison between estimate power and realistic power and optimize the variable step size algorithm judging by the position of work state point . The simulation results show that the controller still has good dynamic performance even when irradiance changes sharply.
The Intelligent Desk Lamp Designed for Special Populations
Authors: Guo Jia Xu , Long Ling
Published: June 2014

For senior citizens and people with disabilities and other special groups, it is inconvenient for them to use the ordinary desk lamp. This essay presents a design scheme of intelligent desk lamp based on infrared detector. Pyroelectric infrared sensor can detect infrared radiation of human, which can be used as the automatic switch to solve the limitation of the manual switch for these special groups. Intelligent desk lamp can meet these crowds on the specialized requirements of everyday lighting lamp according the characteristic. Compared with the traditional household table lamp, this design has the distinct characteristics of intelligence, pertinence and reliability.
The Study on Intelligent Insecticidal Lamp with LED
Authors: Zhang Xiao Dong , Xing Li Feng
Published: June 2014

Intelligent insecticidal lamp with LED is more efficient than ordinary insecticidal lamp. It used solar battery as the power supply, used high voltage power grid as hunting tools, used power LED which was controlled by singlechip as trapping tools for killing more insects. It could work at the night in spring or summer by data acquisition of clock chip and sensors and could automatically shut down in the rainy day or foggy day.
Ranging Technique Based on Conically Scanned Single Pixel Millimeter Wave Radiometer
Authors: Lu Xuan , Wu Li , Xiao Ze Long , Xu Jian Zhong
Published: June 2014

Passive millimeter wave detection offers great advantages of covertness and anti-interference in surveillance and concealed weapon detection but suffers from disabilities of distance measurement. Based on the conically scanned single pixel millimeter wave radiometer, this paper presents a ranging method via dual-measurement utilizing the relation between the solid angle of the object and its distance from antenna. Both one-dimensional and two-dimensional detections are considered. For one-dimensional detection, the relation between the solid angle of the object and the range is reflected by the pulse width of the radiometer output, and the pulse widths of the radiometer output in two measurements could be extracted by derivative or threshold method. Then the range is calculated since it is inversely proportional to the pulse width, which is demonstrated in simulation. For two-dimensional imaging, a scale extracting algorithm is developed to search the scale between the object sizes of bi-measured images. Experiments are performed using a 94.5GHz total-power radiometer mounted on conically scanning platform. The obtained radiometric images are processed by the developed algorithm and the results indicated that both the scale extracting algorithm and the ranging method are effective and practical.
Magnetism in a Spintronic Compound Zr0.8Cr0.2O2 of Small Crystallites
Authors: Sengupta Arundhati , Misra Susmita , Ram Shanker
Published: June 2014

A transition metal ion Cr4+(3d2 spins) doped ZrO2 of small crystallites presents tailored magnetic, electrical and optical properties useful for magnetodielectric and spintronic applications. A liquid polymer precursor gel (Cr4+ and Zr4+ complex with glycerol) when heated in an autoclave at a small pressure 0.6-0.7 atm at 420–470 K results in a compound Zr0.8Cr0.2O2 with an average 5 nm crystallite size of a stabilized cubic (c)-ZrO2-type phase (after 2 h annealing at 773 K in air). A broad Raman band is observed at ~300 cm-1 in acoustic and transverse optic phonons characteristic of the c-ZrO2-type structure, with a prominent O–Cr–O stretching band at 878 cm-1 in a ferromagnetic order. A CrO2/Cr2O3 surface layer exhibits two weak bands at ~1011 cm-1 and 1032 cm-1. The sample exhibits an ‘S’-shaped ferromagnetic hysteresis loop (does not saturate below 60 kOe fields) at 5 K, with a magnetization M = 85.79 emu/g (in the CrO2 part) at 60 kOe and coercivity Hc = 100 Oe. With warming above 5 K, the loop converges progressively with only a weak ferromagnetism at room temperature, M = 9.08 emu/g and Hc = 54.2 Oe. As a pinning barrier, the uncompensated spins in the surface layer supports coercivity at low temperature. A model magnetic structure describes the magnetic properties in correlation to the microstructure.
Infrared Plasmonics via ZnO
Authors: Allen J.W. , Allen M.S. , Look D.C. , Wenner B.R. , Itagaki N. , Matsushima K. , Surhariadi I.
Published: June 2014

Conventional plasmonic devices involve metals, but metal-based plasmonic resonances are mainly limited to λres < 1 μm, and thus metals interact effectively only with light in the UV and visible ranges. We show that highly doped ZnO can exhibit λres ≥ 1 μm, thus moving plasmonics into the IR range. We illustrate this capability with a set of thin (d = 25–147 nm) Al-doped ZnO (AZO) layers grown by RF sputtering on quartz glass. These samples employ a unique, 20-nm-thick, ZnON buffer layer, which minimizes the strong thickness dependence of mobility (μ) on thickness (d). A practical waveguide structure, using these measurements, is simulated with COMSOL Multiphysics software over a mid-IR wavelength range of 4–10 μm, with a detailed examination of propagation loss and plasmon confinement dimension. In many cases, Lplas < λlight, thus showing that IR light can be manipulated in semiconductor materials at dimensions below the diffraction limit.
A Simple Low Temperature and Pressure Method for the Synthesis of Quasi-One Dimensional Nano Structures of TiO2 for Dye Synthesized Solar Cells
Authors: Karimipour Masoud , Zar Mozhdeh Khancheh , Molaei Mehdi
Published: June 2014

In this work we have synthesized TiO2 nanostructures using a modified autoclave-free hydrothermal method from bulk powders. In the absence of pressure, Toluene was used as the dispersing agent to prohibit particle aggregation during the thermal treatment. Toluene to Ti mole ratio (X) was varied from 0 up to 30 to obtain different morphologies of TiO2. X-ray diffraction (XRD) analysis demonstrated the Anatase phase for all the samples. FTIR analysis indicated that samples are free of carbon rich compounds and carbon contaminants. SEM images showed that with the increase of Toluene to Ti ratio, the morphology of the powders change from spherical particles with an average size of about 45 nm for X=0 to broccoli-shape structure for X=10, nanotubes for X=20 and nanosticks/wires for X=30. The synthesized TiO2 nanotubes have been used as photoanode in a dye synthesized solar cell (DSSCs). The efficiency of the fabricated solar cell without any further modification was obtained about 2.3%.
Effect of Heat Treatment on CNT/TiO2 Photoelectrode for Dye-Sensitized Solar Cells Application
Authors: Razali Mohd Zikri , Huda Abdullah , Shaari Sahbudin , Taha Mohd Raihan , Omar Azimah , Yarmo Mohd Ambar
Published: June 2014

In this research, the CNT/TiO2 nanocomposite solution was prepared using sol-gel method process. Definite amounts of CNT (0.06 g) were sonicated in 30 ml anhydrate 2-propanol. The measured quantities of Titanium (IV) Tetraisopropoxide (TTIP) – 5 ml were introduced into the CNT/2-propanol solution. The CNT/TiO2 paste was doctor-bladed onto the FTO glass and consequently annealed at 250 °C, 350 °C and 450 °C for 30 min. The effect of annealing temperatures on the CNT/TiO2 thin films was discussed. The CNT/TiO2 thin films were characterized for morphological and electrical performance by Field Emission Scanning Electron Microscopy (FESEM), X-ray Diffraction (XRD), Incident Photon to Charge Carrier Efficiency (IPCE) and IV-Curve Efficiency analysis. The XRD patterns show the thin films major peak at (101) with average anatase phase crystallite size. The CNT/TiO2 thin film's morphological structure composed of compressed and porous distributed composition. The crystal structures were changed upon increasing the annealing temperature. The IV measurement shows that the dye-sensitized solar cell (DSSC) at 450 °C produced highest photoelectric conversion efficiency (η) with 3.88 %. IPCE graph shows the solar cell absorb light within the UV spectrum region. It is revealed that annealing temperature has influence toward photovoltaic performance of the assembled DSSC.
Influence of Mg Concentration on Structural, Optical and Electrical Properties of Epitaxial-Grown Mg-Doped C60 Thin Films
Authors: Morales C. , Kojima N. , Ohshita Y. , Yamaguchi M. , Nishi S. , García G. , Juárez H. , Díaz T. , Pacio M. , Rosendo E. , Romero A.
Published: June 2014

The effect of magnesium doping in C60 films grown on mica was studied. An improvement on the conductivity of the films was observed when the concentration of magnesium was increased. Structural changes were also observed from the diffraction patterns of x-ray at high magnesium concentrations. A new peak in the photoconductivity spectra was observed. This new peak was also attributed to structural changes, which would lead to some changes in the carrier transport properties. The pentagonal pinch Ag(2) mode of the Raman spectra weakened and shifted to lower frequencies when the magnesium concentration increased, which indicates that the C60 molecule cage changed.
Chemical Functionalization of Carbon Nanotubes and its Effects on Electrical Conductivity
Authors: Moreno Marcelino José Encarnación , Vigueras Santiago Enrique , Lopez-Tellez Gustavo , Hernández López Susana
Published: June 2014

This work presents the study of the electrical conductivity in MWNT as a function of three different chemical functionalization conditions. Unmodified and chemically modified MWNT were characterized by microRaman spectroscopy, XPS and SEM whereas the electrical conductivity was determined by dust compression technique. MWNT were modified using three different oxidation conditions: (1) a mix of concentrated acids, H2SO4/HNO3 (3:1, v/v) sonicated for 2 h; (2) same mixture as (1) but using mechanical stirring for 6 h and (3) a reflux of an aqueous solution of HNO3 (20%, v/v) and mechanical stirring for 6 h. The characterization evidenced different functionalization degrees, based on the formation and detection of functional groups such as ether, carbonyl and carboxyl in different percentages. The unmodified CNT presented a conductivity of 510 S/m which decreased as the functionalization degree increased. For reactions (1) and (2) such conductivity was reduced by 8.8 and 15.5%, respectively, whereas for condition (3) it only decreased 0.98%.
Effect of the Particle Size on the Microwave Absorption in the Yttrium-Iron Garnet
Authors: Sánchez Herlinda Montiel , Alvarez Guillermo  L. , Conde-Gallardo A. , Zamorano R.
Published: June 2014

A comparative study between micropowders and nanopowders of Y3Fe5O12 (YIG) by means of ferromagnetic resonance (FMR) is reported. Significant changes in lineshape of the FMR spectra between both samples are observed, in particular, the absorption mode in nanopowders have an internal structure which can be associated with magnetostatic modes. Additionally, a method to measure the non-resonant microwave absorption, as function of an applied magnetic field around zero field, known as the low-field microwave absorption (LFMA) is also employed. LFMA technique is used to give a further knowledge on the YIG samples, showing their main characteristics highlighted. These techniques are powerful tools for the research of magnetic materials at microwave frequencies.
Photonic Bloch Oscillations and Zener Tunneling in Dual-Periodical Multilayers Made of Porous Silicon: Effect of Angle of Incidence
Authors: Estevez J.O. , Arriaga J. , Reyes-Ayona E. , Agarwal V.
Published: June 2014

Experimental evidence of photon Bloch Oscillations (PBOs) and Zener tunneling (ZT) in dual-periodical (DP) superlattices made of porous silicon (PSi), is presented. An introduction of linear gradient in physical layer thicknesses in DP structure, composed by stacking two different periodic substructures N times, where (N-1) resonances appear, i.e, WSLs resonances and Zener tunneling of the nearest resonances of two consecutive minibands can be observed depending on the values of applied gradient. Theoretical time-resolved reflection and scattering state maps show photonic Bloch oscillations (BOs) and Zener tunneling for a range of incidence angles. Measured reflection reveals the presence of Wannier-Stark ladders (WSLs) and ZT in the near infrared region.
The Influence of Biogenic and Synthetic Starting Materials on the Properties of Porous Hydroxyapatite Bioceramics
Authors: Salma-Ancane Kristine , Stipniece Liga , Locs Janis , Lakevičs Vitalijs , Irbe Zilgma , Berzina-Cimdina Liga
Published: June 2014

The aim of this study was to investigate the influence of biogenic and synthetic starting materials on properties of porous hydroxyapatite (HAp) bioceramics. HAp powders were synthesized by modified precipitation method using biogenic calcium carbonates (ostrich (Struthio camelus) egg shells, hen (Gallus gallus domesticus) egg shells, snail (Viviparus contectus) shells) and synthetic calcium oxides (Sigma-Aldrich and Fluka). Specific surface area, molecular structure and morphology of obtained powders were determined. As-synthesized HAp powders had a varied specific surface area with a wide range from 83 to 150 m2g-1 depending on CaO source. Porous bodies of HAp were prepared by in situ viscous mass foaming with NH4HCO3 as pore forming agent. Foamed and dried green bodies were sintered at 1100 °C. The obtained bioceramics were investigated using Archimedes method, field emission scanning electron microscopy and Brunauer-Emmett-Teller method. There are considerable differences between porous HAp bioceramics structures prepared from different sources of CaO. The choice of starting material substantially affects the macro-and microstructure of prepared porous bioceramics.
Instrumental Color Evaluation of Ceramic Materials by Using Two Dental Spectrophotometers
Authors: Gasparik Cristina , Botos Alexandra , Culic Bogdan , Badea Mindra , Dudea Diana
Published: June 2014

Objectives: The aim of the present study was to evaluate the precision of two dental spectrophotometers in evaluating the color parameters of ceramic materials and to assess the accuracy of a dental spectrophotometer (Shade Pilot, Degudent) for analyzing color parameters of lithium-disilicate ceramic materials. Methods: The CIE L*a*b* color parameters, chroma and hue angle of 6 groups of lithium-disilicate ceramic ingots were recorded: MO0, HO0, LTA1, HTA1, LTBL1, HTBL. The measurements were performed in a viewing-booth under a D65 illuminant. Statistical analysis was performed to assess the precision and differences between the two color-measuring devices. Results: Significant differences were found between all color parameters recorded (p<0.001). The difference varied depending on the type of ceramic ingot assessed. The HO0 ingot showed the highest color difference (ΔE=19.18), while the smallest color difference was found for the MO0 ingot (ΔE=5.62). Conclusions: Color parameters of ceramic materials can be recorded with both color-measuring devices, the VEA showing the highest precision.
Researches Regarding the Biomechanics Behaviour of some Impressions Biomaterials Used in Dentistry
Authors: Antohe Magda Ecaterina , Forna Doriana , Forna Norina Consuela
Published: June 2014

The dimensional stability of impression materials is a variable with an impact on the accuracy of dental prostheses; alongside with other factors including the modifications occurred during the material preparation or the impression techniques. The study was based on a laboratory simulation of a clinical situation. The impression materials were: Alginate; Addition silicon materials-AFFINIS and FLEXITIME; Condensation silicon materials-SPEEDEX and OPTOSIL; Polyvinyl siloxane materials-EXPRESS. The impressions were taken at 37 ̊C at 100 per cent humidity and mould in IV class gypsum at intervals of 0 min, 30 min, 1 h, 8 hr, 24 hr and 48 hr. There were taken 3 impressions for each time interval, for each material type as well as for the 2 storage conditions, with a total number of 252 impressions. The measurements of this study were limited to the linear dimension, being observed the changes occurred in one direction, although contraction is a volumetric modification. The statistic assessment of the measurement data obtained in the case of the same type of addition silicon materials recorded an increase of the volumetric contraction type in dry environment and in longer time intervals. The Express material has less significant deformation at room temperature, compared to its being exposed to moist environment. The least significant deformations were recorded in the case of polyether materials automatically mixed.
Translucence Study through New Experimental Hybrid Composites
Authors: Pastrav Ovidiu Cristian , Delean Ada Gabriela , Sarosi Codruta , Silaghi Dumitrescu Laura , Muntean Alexandrina , Gociu Marius , Moldovan Marioara
Published: June 2014

Translucence parameters for 3 series of experimental hybrid composites were investigated using three-chromatic coordinates such as L* a* b* CHROMA technique using a type C illuminant geometry with the scope of 8o. The materials of each series contain in the same ratio different copolymers and a filler mixture (simple and mixed hydroxyapatite-ZrO2 or SiO2 powders and glass powders with barium oxide, respective strontium oxide, or quartz powder). The purpose was to determine the effect of filler composition of composites on translucence. The analysis shows that these materials have more or less translucence. CHROMA determinations indicate that for the composite that has as filler quartz microparticles anh hydroxyapatite nanoparticles, the translucence registered is higher. Results leading to the idea that chemical composition and the size of inorganic phase are important to obtain translucent composite materials that have very natural in appearance. Keywords: translucence, hybrid composites, CHROMA method.
Early Degradation of Resurfacing Prostheses
Authors: Cirstoiu Catalin , Popescu Dan , Ene Razvan , Cîrstoiu Monica
Published: June 2014

The resurfacing arthroplasty is a new method, superior techniques used in hip arthroplasty, through the immediate post-operative recovery and distance, followed by a complete reversal of limb function and a minimum rate of postoperative complications. Performance of this prosthesis is evident in well selected cases (young patients with physical activity) after a surgical indication correctly formulated. 39 patients with aseptic necrosis of the femoral head prosthesis underwent surgery with total hip resurfacing type in Clinical Orthopaedics-Traumatology, University Hospital Bucharest between 2005-2009.
The diagnosis was established by X-ray and MRI examination. Sex ratio was: 22 men and 17 women. Age groups: 11 patients 20-30 years, 30-40 years 16 patients, 12 patients over 40 years... Approach was developed by postero-lateral joint capsule being maintained to preserve femoral vasculature. Recovery was fast in a short amount of time patients. All patients were reviewed clinically and radiographically at 4 weeks, 6 weeks, 3 months, 6 months, and 12 months, then annually.
There were 5 cases of revision after resurfacing arthroplasty type of causes independent of design and composition of these prostheses. Revision surgeries of these prostheses have gone easier than in the case of conventional prostheses. Most times it is enough just replacing the stem, keeping torque meta-metal large head with all its benefits. The importance of this type of arthroplasty is that: are aimed at young people, preserves bone capital, maintain femoral vasculature, rapid, resumption of intense physical activity, complete recovery of movement in the hip joint, lack of formidable complications in hip arthroplasty dislocation represented.
Potential Solutions to Increase the Corrosion Resistance of Metallic Surgical Instruments Using Different Types of Ceramic Coatings
Authors: Razvan Ionescu , Antoniac Iulian Vasile , Cotrut Mihai Cosmin , Miculescu Florin , Eugeniu Vasile , Munteanu Corneliu , Moldan Dorin , Niculescu Marius
Published: June 2014

The overwhelming majority of medical instrumentation are executed form metalic materials, form the category of austenitic steinlees steel and titan alloys, which poses a good rezistance to corrosion, appropriate mechanical properties, and a good biocompatibility. The lifetime for the medical instrumentation is generaly low due to the modification of surface properties of metal tools from poor maintenance by medical personnel performing decontamination and sterilization operations (having no knowledge of material science), or the the improper use of chemical reagents or low quality of water used in decontamination processes. Identified solutions to improve surface properties of these parts of surgical instruments made ​​of metallic consist of deposition of protective coatings. In this experimental study, we perform different coatings on a substrate made by stainless steel type 316L. We use different coating materials, each deposited ​​by a specific method: hard ceramic biomaterials (TiO2 and YSZ - yttria stabilized zirconia) deposited by the method of deposition and plasma, respectively zirconium carbonitride (mono and multilayer) deposited by cathodic arc deposition method.
The obtained coatings was analyzed using scanning electron microscopy coupled with EDS in order to characterize the morphology and composition of the coatings. The selected samples were tested for corrosion resistance. Corrosion resistance was determined by linear polarization technique, which involves plotting the potentiodynamic polarization curves of-1 V (vs. OC) to 1 V (vs SCE), with a scan rate of 0.5 mV / s. The corrosion tests was performed in physiological saline infusion (NaCl concentration 7%) at room temperature (25 ± 1 ° C) according to ASTM G15-97a. As a general conclusion we can say that layers ZrCN based presents the best parameter values ​​of corrosion and therefore the best corrosion resistance in the case of surgical instruments.
Our Experience with Alumina on Alumina Weight Bearing in Everyday Orthopedic Practice
Authors: Grecu Dan , Tarnita Dan , Tarniţă Daniela , Nita D.R.
Published: June 2014

The research for an ideal hip prosthesis has led to the development of several durable materials that have been tested very intensly during the past decades, both clinically and mechanically. Alumina on alumina bearing has proven to be a very reliable bearing and is used more and more often. Nevertheless, because of the lack of ductility of alumina ceramic, concerns have been raised regarding its risk of fracture. The purpose of our study is to evaluate the mid-term results (78 months follow-up) of alumina on alumina prosthesis and the complications that have appeared regarding to the properties of the implant. We have reviewed retrospectively 89 THA performed in our clinic during October 2005 – October 2013 on a follow-up period of maximum 78 months. The mean age of the patients included was 49,60 years for men and 48,44 years for women. It was used a single kind of implant with same type of alumina parts, applied only on a postero-lateral surgical approach. The survival rate of ceramic-on-ceramic bearing surface by itself was 98.87% (88 out of 89). The most frequent complication was the dislocation of the prosthesis that happened in 7 cases, mainly due to a malposition of the acetabular cup, without any damage done to the ceramic bearing surfaces. In the failed case we have encountered a cracked femoral head that has been previously resterilized by steam. We could conclude that the alumina on alumina prosthesis is a very reliable prosthesis regarding its durability and strength. It requires a very precise surgical technique when implanted, since almost all the complications were due to a malposition of the acetabular component. A postero-lateral wall of the liner might decrease the rate of dislocations and ceramic wear. Also, we might debate that the steam sterilization is not suitable for alumina implants, since the fractured femoral head was resterilized.
Biomimetic Apatite Deposition within Casein-Loaded Hydrogel Scaffolds
Authors: Serafim Andra , Vasile Eugeniu , Cristescu Ioan , Istodorescu Mircea , Stancu Izabela Cristina
Published: June 2014

Casein is a phosphoprotein and accordingly, its capacity to induce formation of apatite was investigated using a biomimetic method. The protein was physically immobilized into a synthetic polymer network generating hybrid scaffolds. The obtained hydrogels contained uniformly distributed nanosized casein grains. The incubation of such materials in synthetic body fluid (SBF 1.25x) led to formation of nanosized biologic-like apatite. The resulting materials have been characterized by infrared spectrometry and scanning electron microscopy.