bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Studies on Wire Electric Discharge Cutting of SiCp/6061 Aluminum Metal Matrix Composites
Authors: Shandilya Pragya , Jain N.K. , Jain P.K.
Published: November 2010

This paper reports about the experimental findings on the wire electric discharge cutting (WEDC) of 6061 aluminum metal matrix composite (MMC) reinforced with silicon carbide particulates (i.e. SiCp/6061 Al). Four WEDC parameters namely servo voltage, pulse-on time, pulse-off time and wire feed rate were varied to study their effect on the quality of cut in SiCp/6061 aluminum MMC using average cutting rate and microstructure of the cut surface as response parameters. The experiments were conducted using one-factor-at-a-time experiment strategy in which only one input parameter was varied while keeping all other input parameters as constant. The experimental results indicate that the average cutting speed is mainly affected by pulse-on time, pulse-off time, and voltage and the changes are more prominent for the MMC 7.5% SiCp. The characteristics of the surface produced by WEDC were analyzed by scanning electron microscopy (SEM). Analysis of SEM images of the cut surface has revealed that the depth of micro-voids and micro-cracks slightly increases as the voltage and pulse-on time increases and as pulse-off time and wire feed rate decreases. there seems to be trade-off between the average cutting speed and better quality of cut for Al-SiCp MMC as far the values of pulse-on time, pulse-off time are considered and final choice will depend upon the type of application. An optimum range of the input parameters has been bracketed as the final outcome of this work for carrying out further research to develop the models for WEDC of SiCp/6061 aluminum MMC and to optimize the WEDC parameters for the best quality of cut and to minimize the wire breakage frequency.
A Taguchi-Neural-Based In-Process Tool Breakage Monitoring System in End Milling Operations
Authors: Huang Po Tsang B. , Chen James C. , Lin Chiuhsiang Joe , Lyu Peng Hua , Lai Bo Chen
Published: November 2010

The use of CNC machines is one of the successful factors in the computer integrated manufacturing (CIM). Even though the CNC machine can automatically perform the machining processes, some of the situations that may significantly influence the quality of product such as a cutting tool breakage. Therefore, to prevent the machine from damaging and ensure the quality of product, it is important to develop a system that can monitor the tool conditions. The purpose of this study is to develop a Taguchi-neural-based in-process tool breakage monitoring system in end milling operations that can monitor the tool conditions and immediately response a proper action.
For an in-process tool breakage monitoring system, a neural network was applied to making decisions of monitoring. One of the disadvantages of neural network is the training processes. It is difficult to determine an optimal combination of training parameters of neural networks. Traditionally, the try-and-error method is time-consuming and without systematic base. Therefore, the optimization of training parameters for neural networks using Taguchi design was applied to training the neural network model and to enhance the accuracy of the tool breakage monitoring system.
A Real-Time Condition Monitoring System for a Machine Tool Spindle
Authors: Ho Chao Ching , Kuo Tzu Hsin , Tsai Tsung Ting
Published: November 2010

Designing a robust condition monitoring system for a machine tool spindle is an important task because the spindle has a significant effect on the processing quality. In this study, a solar-powered wireless sensor system is installed inside the spindle and is used to monitor the machine tool processing state in real time, thereby improving the processing quality. Accelerometer sensors are employed to estimate tool wear; these sensors monitor the vibration of the spindle. The vibration monitoring data of the high-speed spindle is wirelessly transmitted to an external information device in real time. As an alternative to sensors that employ wired power transmission, a solar energy transmission system has been developed to provide the required electric power to the sensor system. The experimental results show that the proposed system successfully measures the vibration frequency of the rotational machine tool spindle.
A Method of Business Process Modeling Based on Petri Net
Authors: Hao Yong Ping , Xu Xiao Lei , Shao Wei Ping , Zeng Peng Fei
Published: November 2010

Through the analysis of the execution and dispatching principle of the Petri net, the business process management mode based on Petri net is proposed. We merge the place node and the transition node, and reside the token in the node. The only token in process instances and the sub-token in parallel process are introduced, which can avoid conflicts caused by multi-tokens. The business process model for the drawings design and approval is established, and it is verified by the workflow modeling system.
A Method for Evaluation of Green Degree in Green Supply Chain
Authors: Yu Bao Qin , Zhang Yue
Published: November 2010

Green supply chain management is a method to reduce the ecological impact of the whole supply chain and make the most efficient use of resources. In this paper, the data mining (DM) technique is utilised to evaluate green degree in green supply chain. Then the process of the evaluation is given and a classification model of multivariate decision tree based on rough set is proposed. Finally, a simulation analysis is given to show the application of this method.
Design Meta-Intent Representation and Semantic Annotation
Authors: Zhang Ying Zhong , Luo Xiao Fang
Published: November 2010

The parametric feature-based modeling systems can express design intent at high-level. But they usually lack representations for explaining why the feature is selected, what its design purpose and source are. This paper integrates the design intent object with design rationale and proposes an ontology-based representation framework for design meta-intent information. An approach to ontology instantiation for design intent objects and meta-intent properties by semantic annotating is presented. In order to improve the annotating efficiency the methods to automatically capture the design meta-intent information are also discussed. Based on above approaches the design meat-intent information can be naturally and effectively constructed during design process.
Structural Optimization Using Multi Evolutionary System Co-Exist Genetic Algorithm
Authors: Cheng Dong Mei , Qiu Chang Hua , Liu Cheng Yang
Published: November 2010

Traditional genetic algorithms put all the individuals in one population to cross and adopt the same set of evolutionary parameters and genetic operators to guide the evolution, which will easily lead to local convergence and poor searching efficiency. A multi evolutionary system co-exist genetic algorithm is developed to overcome the fluctuations of the whole evolution process through dividing individuals into several sub-populations according to the fitness value. Moreover, the improved algorithm prevents the early convergent and increases the diversity of individuals by supplying these sub-populations different evolutionary systems. The effectiveness and feasibility of the algorithm are verified by typical genetic algorithm test functions and an engineering case. The results show that the genetic algorithm has a good versatility, high convergence rate and solution precision.
Application and Benefits of the Virtual Reality Technique for Product Conceptual Design
Authors: Lin Chiuhsiang Joe , Lin Shiau Feng , Wang Rou Wen , Sun Tien Lung , Chao Chin Jung , Feng Wen Yang , Tseng Feng Yi
Published: November 2010

Selecting a right way to display the conceptual design results is an important issue for designers. This study evaluated three common computerized visual presentation methods for demonstrating the conceptual ideas of product designs. They are pictures, animations, and image-based VR. After evaluations, this study found that the image-based VR reached the best results of getting the ideas of the conceptual design. It is therefore suggested to use the image-based VR approach if designers wish to receive the most possible advices and feedback, especially in restricted presenting time. The image-based VR approach will help users understand many aspects and considerations of the designer’s conceptual ideas more easily and quickly.
Viscosity Influence Research on Load Capacity of Heavy Hydrostatic Bearing
Authors: Zhang Yan Qin , Yu Xiao Dong , Yang Xiao Dong , Sun Gui Tao , Yu Xiao Yang , Shi Zhi Min
Published: November 2010

Lubricant viscosity is one of the key parameters in hydrostatic bearing research. In order to solve the load capacity of hydrostatic bearing in the heavy equipment, viscosity-temperature equation of lubricant film is established, and the viscosity-temperature curve is fitted by B-Spline curve. Finite volume method is used on numerical simulation of pressure field of heavy hydrostatic bearing in constant and variable viscosity respectively and in different rotational velocity, whereafter, viscosity influence on load capacity of heavy hydrostatic bearing is discussed. The results show that, viscosity impose a minor influence on cavity pressure of hydrostatic bearing when rational velocity is low; whereas, when rational velocity is high, especially to the heavy hydrostatic bearing which with high liner velocity influence of viscosity changing must be taken into account in calculation. Numerical simulation results reflect the pressure distributing state of bearing veritably; furthermore, these provide theoretical basis for hydrostatic bearing design and lectotype in practical application.
Rolling Force Research on Cogging Rolling of H-Beam
Authors: Qin Qin , Wu Di Ping , Li Jing Jing , Zang Yong
Published: November 2010

Due to the complexity of H-beam’s cross section, it is difficult to calculate the rolling force and force torque accurately using classic formulas conveniently when H-beams of new size are developed. This paper describes an investigation into the reversing process of H-beam using MARC software and compares the results with rolling data from the production line. A FEM model involving in three-dimensional, elastic-plastic and thermo-mechanical coupling has been established successfully to predict multi-pass rolling process. The analysis produces outputs such as deformation rules, rolling force and the web thickening. The influence of rolling reduction, the reduction rate between the web and flange are also discussed. The indications are that there is much difference between the measurement of rolling force and the rolling force calculated by using classic formulas. The reason is that real reduction during rolling process is much more than the scheduled one. A new revised method was suggested to calculate the rolling force. The simulation results show that this new method for calculating rolling force is feasible.
A Product Family Genealogy Based Configuration Model
Authors: Zhang Wen Lei , Yu Jia Peng , Yu Hong
Published: November 2010

Product variation and customization is a trend in current market-oriented manufacturing environment. Product configuration is the key technology in this customization environment. But complex customer requirements are still hard to resolve. So the purpose of this study is to offering a new intelligent configuration algorithm to this problem, which is based on Product Family Genealogy Model (PFG). Characteristics of customer group, modules and product platform are discussed to build a PFG model - a hierarchy of reasonable configuration models. Based on it, both the customer requirements and constraints are classified and treated respectively. So the product configuration task can be easily accomplished by four sequenced stages i.e. “PFG position”, “key configuration”, “basic configuration”, and “form configuration”. Finally, an example of desktop configuration is presented to demonstrate this approach.
Dye-Sensitized Solar Cells Built on Plastic Substrates by Low-Temperature Preparation of Semiconductor Films
Authors: Miyasaka Tsutomu
Published: November 2010

Printable materials and technologies to realize low-cost dye-sensitized solar cell fabricated on thin plastic substrates are reviewed. Mesoscopic conductive materials and pastes that enable low-temperature coating of electrochemically active films for photoanode and conterelectrode are described in aspects of material preparation, electrochemical and photovoltaic behavior, and stability of the plastic electrode. Performance of plastic solar cells and modules are discussed with respects to the structure and thickness of the non-sintered mesoporous films, light-harvesting functions of dyes, and optimization of electrolyte compositions. Commercial advantages of the lightweight, flexible cell in power generation are also introduced based on proof-of-concept tests with large-area modules.
Synthesis of Plate-Like SrTiO3 Particles
Authors: Zhao Wei , Pan Ruo Cai , Xue Hao
Published: November 2010

Micro-scale plake-like SrTO3 particles were synthesized by two routes of topochemical conversion. One is by growing on Sr3Ti2O7 (S3T2) core particles in molten salt condition, and the other is from the layer-structured SrBi4Ti4O15 (SBT) precursor in a KCl medium. The effects of the morphology and size of the precursor to platelet SrTiO3 crystals were studied. X-ray diffraction analysis revealed that the crystallographic {010} plane of SBT was converted into the pseudo-cubic {001} plane of SrTiO3. The polycrystalline SrTiO3 particles from BST precursor exhibited a plate-like shape with 10-15μm in length and a high aspect ratio, and were more suitable for preparing textured ceramics by templated grain growth process than the platelets from the S3T2 precursors.
Analysis of Stress in Aircraft Components Using Lock-In Thermography
Authors: Liu Xun , Liu Jun Yan , Li Xu Dong , Zhang Guang Yu
Published: November 2010

This paper describes a theoretical and experimental analysis on full-filed stress distribution from thermoelastic measurements and its application to determination of stress concentration. The sum of the principle stress can be measured by Thermal Stress Analysis (TSA). Lock-in Thermography is very effective tool to measure the structure stress distribution by its high thermal resolving. In this study, the thermoelastic effect theory is described and the relationship between the temperature and the applied stress is developed in an elastic material. Experiments were carried out with 2A12 aluminium alloys plate and ones with hole structure under cyclic load. The thermoelastic effect coefficient is obtained for 2A12 aluminium alloys materials, and the effect law is analyzed that the stress value measured was affected by load frequencies. The optional load frequency is obtained, and that is, the load frequency is selected greater than 3.5Hz for 2Al12 materilas, and it was found that the structure stress can be evaluated with good accuracies by the lock in thermography. The experiment was carried out for aircraft components stress distribution measurement and structure stress analysis. The experimental results show the stress concentration position is easy found from stress distribution by lock-in thermography.
Synthesis and Antibacterial Activity of Acylated Chitosan
Authors: Wang Jiang Tao , Lian Zi Ru
Published: November 2010

Chitosan, a biocompatible, biodegradable, nontoxic polymer, is prepared from chitin, which is the second most naturally occurring biopolymer after cellulose. Sorbyl chitosan and p-aminobenzoyl chitosan were synthesized working under high-intensity ultrasound and their antimicrobial properties were analyzed against Escherichia coil, Staphylococcus aureus and Aspergillus niger. The structures of the derivatives were characterized by FTIR spectroscopy and elemental analysis. The results indicated that the products had the effect of bacteriostasis and the antibacterial activity increased with increasing the concentration. Acylated chitosan had better inhibiting effect on S. aureus than others. It was also found that the antifungal activities of the derivatives were stronger than that of chitosan.
Electrodeposition of Ni and Ni-Cu Nanowires in Rectified Porous Anodic Alumina Membrane
Authors: Zuo Yan , Tang Juan , Li Xiao Tian , Zhao Yan , Gong Hai Lan , Qiu Shi Lun
Published: November 2010

Highly ordered Ni and Ni-Cu nanowires were electrodeposited into the micropores of the porous anodic alumina (PAA) template which was fabricated by the method of two-step anodizing and the thickness of barrier layer which was formed during the anodizing process was rectified by applying current limited anodization steps. The X-ray diffration (XRD) was used to characterize the Ni and Ni-Cu nanowires and the morphology of these nanowires was examined by the way of scanning electron microscopy (SEM). The SQUID magnetometry was used to investigate the magetic properties of the nanowires. It is found that the coercivity and remanence ratio of Ni-Cu nanowire is larger than that of Ni nanowire.
Preparation and Characterization of Nickel Complex [Ni(1-MeIm)6(BF4)2] in Ionic Liquid
Authors: Sun Jun Sai , Xu Cun Ying
Published: November 2010

Nickel complex [Ni(1-MeIm)6(BF4)2, 1-MeIm = 1-methylimidazole] has been prepared in 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4) ionic liquid by a simple solution phase method. The complex was characterized by elemental analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared absorption spectroscopy (IR) and thermal analysis. SEM image indicates that the complex is irregular platelets with an uneven thickness in nanometer scale and variable transverse and longitudinal size, from 0.6 to 4 μm.
Interface Properties of Au/CdZnTe Formed by Different Method
Authors: Qin Kai Feng , Wang Lin Jun , Zhang Ji Jun , Min Jia Hua , Liang Xiao Yan , Huang Jian , Tang Ke , Xia Yi Ben
Published: November 2010

In this paper, the effects of different metal contact treatments were systemically investigated. The interfacial properties between Au and CdZnTe (CZT) made by different methods including the electroless deposition, thermal evaporation and sputtering process were investigated by the Auger depth profiles, the adhesion force measurement, and the accelerated aging tests. The current-voltage (I-V) characteristics and the detector response to gamma-rays from 241Am for different Au contact treatments were also identified.
Synthesis and Luminescent Properties of a New Green Phosphor CaO:Tb3+,Li+
Authors: Wang Ren Qing
Published: November 2010

CaCO3 was chosen as main raw material and wet chemical method was used to prepare the precursor. The precursor was directly sintered at 1060oC with reducing atmosphere for 3 h to obtain new green CaO:Tb3+ ,Li+ Phosphors. The effects of the content of the doping ions Tb3+ and Li+ on the luminescent properties have been studied. The structure, morphology and luminescent properties of the phosphors were characterized by XRD, laser particle size analyzer, SEM, UV and PL-PLE spectra respectively. The results showed that the CaO:Tb3+,Li+ was a single face-centered cubic crystals, the phosphor particle distributed uniformly, the average size of particle was 2μm. The phosphor has a strong absorptive capacity excited by 282 nm ultraviolet ray, and could emit the strong green light with the wavelength of 543 nm(5D4→7F5). The CaO:Tb3+,Li+ is a new type of green fluorescent material.
Synthesis and Luminescent Properties of Violet-Ultraviolet Long Afterglow Phosphors
Authors: Wu Hao Yi , Hu Yi Hua , Wang Yin Hai , Fu Chu Jun , Kang Feng Wen , Li Xiang
Published: November 2010

The M1.99MgSi2O7: Ce3+0.01 (M: Ba, Sr, Ca) phosphors were prepared by the solid-state reaction method. All the samples emit the violet-ultraviolet light with a broad emission band from about 330 nm to 500 nm. All the phosphors samples show a long afterglow. The strongest afterglow intensity and the longest decay duration of the afterglow come from the Ca1.99MgSi2O7: Ce3+0.01 sample. It is attributed to the suitable trap depth and the high trap concentration of this sample. The traps of these phosphors are induced by the lattice defects. A suitable model involving the cation vacancies and the oxygen vacancies, which act as the hole traps and the electron traps respectively, is proposed.
Electronic and Optical Properties of the Zn and Mg Doped AlN
Authors: Cai Xue Mei , Luo Yuan
Published: November 2010

The electronic and optical properties of hexagonal wurtzite AlN doped with Zn and Mg are studied based on the density functional theory. The density of states, dielectric function and absorption spectra are calculated using plane-wave ultrasoft pseudo-potential and the generalized gradient approximation (GGA). The absorption peaks are found during 0-13 eV and 43-48 eV in Mg doped AlN, while in Zn doped AlN, only during 0-15eV. The absorption peak about 43-48 eV found in Mg doped AlN is due to the transition of the deep 2p energy level in Mg to conduction band. The first peak of the dielectric imaginary part is related to the transition of the doped atoms. The peak of the dielectric imaginary part and absorption peak appears about 8 eV is due to the transition of N 2p to Al 3p state. Results show that the electronic and the optical properties of hexagonal wurtzite AlN are directly related to the electronic structure of the impurities in the crystal.
Preparation and Characterization of Skin-Colored N-Doped ZnO Nanocrystals
Authors: Hu Han Mei , Deng Chong Hai , Fang Qiang , Gao Ya , Song Meng Wei
Published: November 2010

In this paper, we report a simple two-step approach (microwave-calcinating) to prepare skin-colored N-doped ZnO nanocrystals. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS) and UV-visible absorption were used to characterize the as-synthesized products. The FESEM results reveal the products mainly take on the morphology of porous flake constructed by 20 nm nanoparticles. UV-Vis spectrum shows a strong absorption peak located at 384nm.
Synthesis and Infrared Transmittance of Curved Surface Diamond Film
Authors: Li Duo Sheng , Zhou Xian Liang , Zuo Dun Wen , Hua Xiao Zhen
Published: November 2010

The growth of polycrystalline curved surface diamond film using direct current plasma jet CVD (DCPJCVD) is measured by those techniques. The relationships between morphology, microstructure, and film quality are investigated by scanning electron microscopy (SEM) and Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), respectively. The results show that, after molybdenum substrate was polished by series of diamond powder, atom hydrogen etching, respectively, a much higher nucleation density can be achieved. Synthetic diamond film is compact, continuous and uniform, and diamond film grows with the columnar spreading from the nucleation surface to the growth surface, (111) faces were dominant in polycrystalline texture diamond film. Raman spectrum indicates that there is only diamond characteristic peak in diamond film, and high quality curved surface diamond film was prepared. IR transmittance of curved surface diamond film in the range of 750 - 4300 cm-1 reached about 60%. Meantime, the IR transmittance was almost the same in the central and fringe regions of the film. These properties indicate that curved surface diamond film has a promising application in infrared windows and dome.
Research on Light Amplification Panel Based on Stimulated Radiation
Authors: Xu Yong Kui , Tang Yuan He , Yang Xu San , Zhang Xun , Zhang Huan Huan , Wang Shui Wei , Liu Yao , Gao Gang , Yang Zhi Kai , Wang Tan
Published: November 2010

Light amplification panel (LAP) based on laser principle is put forward in this paper. The LAP is coupled between the camera and eyepiece of the night vision devices to realize image intensification. The quality of imaging in low level light is gained enhancement. After analysis on principle of LAP, its gain, detection capability, imaging performance, noise and bandwidth are calculated theoretically. Laser media arranged alternately amplifies signals of different wavelength, broadening the bandwidth and also realizing night vision color imaging by physical mode.
Synthesis, Photoisomerization and Thermo-Optic Property of Azo Optically Active Polymer
Authors: Ge Chang Hong , Qiu Feng Xian , Gu Xiao Xian , Yang Dong Ya
Published: November 2010

A novel azobenzene optically polymer (P-DA) was synthesized based on the azo chromophore molecule, chiral reagent L(-)-tartaric acid, acryloyl chloride and methacrylate. The P-DA was characterized by FT-IR, UV-Vis spectroscopy, 1H NMR, DSC and TGA. The P-DA had high thermal stability up to its glass-transition temperature (Tg) of 110 oC and 5 % heat weight loss temperature of 199 oC. The UV-induced trans/cis photoisomerization and reflex-isomerization behaviors were investigated. The results indicated that the P-DA solution could undergo photochromism after irradiated by 365 nm UV light. The optical parameters: refractive index (n), the dielectric constant (ε) and thermal volume expansion coefficient (β) of P-DA were obtained. The thermo-optic coefficients are one order of magnitude larger than those of the inorganic materials, such as SiO2 (1.1×10−5 oC -1 and LiNbO3 (4×10−5 oC -1) and was larger than the organic material such as polystyrene (-1.23×10-4 oC -1) and PMMA (-1.20×10-4 oC -1). The conclusion had a little significance to develop optical communication.
Electron Mobility Model for Strained-Si/(001) Si1-XGex
Authors: An Jiu Hua , Zhang He Ming , Song Jian Jun , Wang Xiao Yan
Published: November 2010

There has been much interest in the Si-based strained technology lately. The improvement of strained-Si device performance is due to the enhancement of the mobility, so the further study on mobility is essential in both theory and practice aspects. In this paper, an analytical model of the electron mobility of strained-Si material, such as biaxial tensile strained-Si material grown on relaxed Si1-xGex (0≤x≤0.6) substrates, as a function of strain and different orientations is obtained. The results show that the electron mobilities for [100] and [010] orientations increase rapidly with increasing Ge fraction x, and there is no electron mobility enhancement for [001] orientation in comparison to relaxed Si material.
Template-Free Synthesis of CuInS2 Hollow Nanospheres
Authors: Hu Han Mei , Deng Chong Hai
Published: November 2010

CuInS2 hollow nanospheres composed of nanoparticles have been fabricated through a solvothermal reaction in ethylene glycol solution (EG) at 200 °C in the absence of any templates or surfactants. The as-obtained CuInS2 products were characterized by XRD, FESEM andTEM. Results show that the synthesized hollow nanospheres are made up of small nanoparticles with a size of 10 nm and the outer diameters of these spheres change from 200 to 400nm. The possible formation mechanism of CuInS2 hollow nanospheres is simply discussed.
Influence of Fe Doping on the Oxygen-Ion Diffusion and Electrical Conduction of La1.95K0.05Mo2-XFexO9-δ
Authors: Li Chun , Li Da , Fang Qian Feng
Published: November 2010

Based on the oxygen ion conductor La1.95K0.05Mo2O8.95, a series of Fe-doped samples La1.95K0.05Mo2-xFexO9- (x=0, 0.025, 0.05, 0.1) were prepared with conventional solid reaction method. The effects of Fe doping on the structure, oxygen ion diffusion and electrical conductivity were studied. Based on the results of conductivity measurements, it can be concluded that Fe doping can improve the conductivity obviously, and doping of both Fe and K samples have better conductivity, which successfully suppresses the phase transition.
Preparation and Properties of Polyimide/SiO2 Hollow Spheres Composite Films with Good Dielectric Property and Amazing XRD Spectra
Authors: Yuan Yuan , Wang Yu , Xie Bing
Published: November 2010

Excellent dielectric property and amazing X-ray Diffraction spectra were found for the novel polyimide films by composing SiO2 hollow spheres with different wt%. The dielectric constants of that from different dianhydrides were ranged of 1.9-3.1 at 1MHz. It was sure that the dielectric constants of the films could be tunable in wider range with different wt% SiO2 hollow sphere as well as different dianhydrides. And in the X-ray Diffraction spectra, some films not only presented wide diffractive peaks of amorphous structures, but also showed sharp crystal peaks at 58.7o and 28.4o. And the Intensity of the sharp crystal peak was dramatically related with the value of dielectric constants. It might be caused by the ordered structure in part of polymer chain. And the structures and properties of the composite thin films were also measured with scanning electron microscope and dynamic themomechanical analysis et al.
Effect of Li2CO3-V2O5 on the Sintering and Microwave Dielectric Properties of 0.6Mg4Nb2O9-0.4SrTiO3 Composite Ceramics
Authors: Pei Cui Jin , Yao Guo Guang , Tian Xiu Lao , Ma Hong
Published: November 2010

The effects of Li2CO3-V2O5 (LV) co-doped on the sinterability, phase compositions and microwave dielectric properties of 0.6Mg4Nb2O9-0.4SrTiO3 composite ceramics have been investigated. All specimens were prepared by solid-state reaction method and sintered at 1050-1200oC for 5h. With an amount LV addition, the densification sintering temperature is significantly lowed from 1300oC to 1175oC. The non-stoichiometric compounds Sr(NbTi)O3+δ and Mg4(Nb1-xTix)2O9-δ were confirmed by X-ray diffraction and energy dispersive X-ray analysis. For the specimen with 1.5 wt% LV addition sintered at 1175oC for 5 h exhibited dielectric properties: εr=20.1, Q•f=10 240 GHz, τf =0.15 ppm/oC.
Effect of Metallic Ions on Photoluminescence of Porous Silicon
Authors: Zhai Bao Gai , Meng Ming , Ma Qing Lan , Huang Yuan Ming
Published: November 2010

In the present paper, we have not only investigated the top surface and cross-section morphology, but also measured photoluminescence spectra characteristic of porous silicon after deposition of metallic ions by electrochemical deposition employing scanning electron microscopy (SEM) and spectrometer, respectively. It is apparent from the SEM images that the microstructure of porous silicon is seriously ruined by the metallic ions deposited by electrochemical deposition. Most interesting is the finding that in the photoluminescence spectrum of porous silicon after the deposition of metallic ions such as AL3+ and Cu2+, the luminescence band gradually is quenched as the electrochemical deposition progressed. A careful consideration of the results obtained show that according to the basic theory of well-established quantum confinement model, the quenching of photoluminescence spectra of porous silicon may well be attributed to the microstructure fell into ruin. On the other side of the fence, we can interpret the physical origin of the phenomenon in view of the presence of metallic ions which give rise a series of energy level deep in the band gap of porous silicon.
CdS-Intercalated Bentonite/Carbon Composite as Electrode for Sulfide Ion
Authors: Udomphan Kemawadee , Wongchaisuwat Atchana , Meesuk Ladda
Published: November 2010

CdS, a bright yellow precipitate is well known for its optical, electrical, electro-optical and photochemical properties. CdS has also been prepared in the interlayer spaces of layered materials such as laponite and montmorillonite (bentonite). Several properties of intercalated CdS have been studied, but for the best of our knowledge there is no reports on its use. In this work, we applied CdS-intercalated bentonite / carbon composite as an electrode for determination of S2- ion in aqueous solution. CdS- intercalated bentonite was prepared by the in situ solid-solid reaction between Cd(II)-bentonite and Na2S. To construct a potentiometric electrode, CdS-intercalated bentonite was mixed with artificial graphite, polytetrafluoroethylene (PTFE) and carboxymethylcellulose (CMC) in an appropriate ratio. The electrode was used to determine S2- in aqueous solution, graphs of log [S2-] vs measured voltage (mv) gave linear relation up to 3 orders of ion concentrations. Apart from the reproducibility and good precision, the electrode is good for its selectivity, durability and low cost.
Fractal Features Grown from Isotropic Melt of a Cholesterol Liquid Crystal
Authors: Ma Qing Lan , Huang Yuan Ming
Published: November 2010

Fractal features of branch-like structures grown from isotropic melt of a cholesterol liquid crystal were investigated with differential scanning calorimetry, polarized optical microscope and computer-aided simulation, respectively. With box-counting method, we have calculated the fractal dimension to be about 2.558-2.604 for the branch-like aggregates. Our growth simulation and the calculated value of the fractal dimension suggests that the cluster-cluster aggregation model can be applied to the growing processes of branch-like structures from isotropic melt of a cholesterol liquid crystal.
Improved Photovoltaic Efficiency of Polymer Photovoltaic Cells by Microwave Irradiation
Authors: Kim Boeun , Lee Kyeong K. , Lee Sung Koo , Lim Eun Hee
Published: November 2010

In this study, microwave annealing treatment was introduced into poly(3-hexylthiophene) (P3HT):[6,6]-phenyl-C61butyric acid methyl ester (PCBM) and poly(9,9‘-dioctylfluorene-cobithiophene (PFT2):PCBM systems instead of thermal annealing treatment. In both systems, microwave annealing showed photovoltaic performane comparable to that of conventional thermal annealing. Through the UV-vis absorption, atomic force microscopy (AFM) and X-ray diffraction (XRD) studies, we were able to confirm that the microwave annealing increases the crystallization of the P3HT polymer chains.
Influence of Polymer Material on the Sensitivity of Packaged Fiber Bragg Grating
Authors: Li Zhi Zhong , Sun Rong Guang , Liu Qi Jun , Wang Yi Chuan
Published: November 2010

Numerical calculation method is adopted to analyze to the influence of the polymer material on the sensitivity of coated FBG. The calculation results show that, the polymer material with high Young's modulus and high thermal expansion coefficient helps to improve the temperature sensitivity of the coated FBG; and the material with low Young's modulus and low Poisson's ratio helps to improve the pressure sensitivity. The polymer-coated FBG experiment is explored, in which the pressure and temperature sensitivities are enhanced 12-fold and 7-fold respectively.
The Stability of μc-Si:H Materials
Authors: Zhao Zhi Wen , Liu Yu Ling , Liu Xiao Yan
Published: November 2010

The stability of μc-Si:H materials for solar cells was well researched. The light induced degradation of intrinsic μc-Si:H single layer material with different crystal volume fraction deposited were studied. The dependence of light-sensitivity as well as sub gap absorption on light soaking time was monitored. The results clearly showed that the magnitude of relative light induced degradation is closely related to material structure. Amorphous fraction is the key determining factor to light induced degradation. The results showed clearly that the magnitude of relative efficiency degradation is increase with amorphous fraction. The more amorphous fraction located in material, the more degradation was been found. With better structure and optical properties, microcrystalline silicon with transition region is more suitable for the manufacturing of stable Microcrystalline silicon solar cells due to the structure and optical properties.
Depletion of Regulatory T Cells Facilitates Growth of Established Tumors: A Mechanism Involving the Regulation of Myeloid-Derived Suppressor Cells by Lipoxin A4
Authors: Zhang Biao , Jia Haibo , Liu Jing , Yang Zhuoshun , Jiang Tao , Tang Ke , Li Dapeng , Huang Chunmei , Ma Jingwei , Shen Guan-Xin , Ye Duyun , Huang Bo
Published: November 2010

Regulatory T cells (Tregs) are thought to facilitate tumor development by suppressing protective antitumor immune responses. However, recent clinical and laboratory studies show that Tregs are a favorable element against cancer. In this study, we provide evidence that Tregs have both promoting and inhibiting effects on tumors, depending on the stage of tumor development. By using 0.5 mg cyclophosphamide, we constructed a murine liver cancer model in which Tregs were continuously and selectively depleted. Under such conditions, we found that tumor growth was inhibited at early stages but accelerated later on. Analysis of the tumor microenvironment disclosed that long-term Treg depletion by 0.5 mg cyclophosphamide treatment induced Gr-1+CD11b+ myeloid-derived suppressor cells (MDSCs). Ablation of MDSCs by anti–Gr-1 Ab blocked Treg depletion-induced promotion of tumor growth. Furthermore, lipoxygenases 5 and 12, two enzymes participating in the biosynthesis of the lipid anti-inflammatory mediator lipoxin A4, were upregulated or downregulated by Treg depletion or adoptive transfer. Correspondingly, the levels of lipoxin A4 were increased or decreased. Lipoxin A4 thus regulated the induction of MDSCs in response to Treg depletion. These findings suggest that Tregs may play different roles at different stages of tumor growth: promoting early and inhibiting late tumor growth. Our study also suggests that the interplay among Tregs, MDSCs, and lipoxin A4 tunes the regulation of tumor-associated inflammation.
Cutting Edge: Virus-Specific CD8+ T Cell Clones and the Maintenance of Replicative Function during a Persistent Viral Infection
Authors: Bannard Oliver , Kraman Matthew , Fearon Douglas T.
Published: November 2010

Persistent viral infections induce the differentiation and accumulation of large numbers of senescent CD8+ T cells, raising the possibility that repetitive stimulation drives clones of T cells to senesce. It is therefore unclear whether T cell responses are maintained by the self-renewal of Ag-experienced peripheral T cell subsets or by the continuous recruitment of newly generated naive T cells during chronic infections. Using a transgenic mouse model that permits the indelible marking of granzyme B-expressing cells, we found that T cells primed during the initial stages of a persistent murine γ-herpes infection persisted and continued to divide during a latent phase of up to 7 mo. Such cells maintained an ability to extensively replicate in response to challenge with influenza virus expressing the same Ag. Therefore, Ag-experienced, virus-specific CD8+ T cell populations contain a subset that maintains replicative potential, despite long-term, persistent antigenic stimulation.
Normal Mode Flexible Fitting of High-Resolution Structures of Biological Molecules toward SAXS Data
Authors: Gorba Christian , Tama Florence
Published: November 2010

We present a method to reconstruct a three-dimensional protein structure from an atomic pair distribution function derived from the scattering intensity profile from SAXS data by flexibly fitting known x-ray structures. This method uses a linear combination of low-frequency normal modes from an elastic network description of the molecule in an iterative manner to deform the structure to conform optimally to the target pair distribution function derived from SAXS data. For computational efficiency, the protein and water molecules included in the protein first hydration shell are coarse-grained. In this paper, we demonstrate the validity of our coarse-graining approach to study SAXS data. Illustrative results of our flexible fitting studies on simulated SAXS data from five different proteins are presented.
Synthesis of Capsaicin Glycosides and 8-Nordihydrocapsaicin Glycosides as Potential Weight-Loss Formulations
Authors: Katsuragi Hisashi , Shimoda Kei , Kimura Eriko , Hamada Hiroki
Published: November 2010

The enzymatic synthesis of capsaicin glycosides and 8-nordihydrocapsaicin glycosides was investigated using almond β-glucosidase and cyclodextrin glucanotransferase (CGTase). Capsaicin and 8-nordihydrocapsaicin were converted into their β-glucoside and β-maltooligosaccharide (amylose conjugate), i.e. β-maltoside and β-maltotrioside, by sequencial glycosylation with almond β-glucosidase and CGTase. The β-glucoside and β-maltoside of capsaicin and β-glucoside of 8-nordihydrocapsaicin showed inhibitory effects on high-fat-diet-induced elevations in body weight of mice.
Design of Druglike Small Molecules for Possible Inhibition of Antiapoptotic BCL-2, BCL-W, and BFL-1 Proteins
Authors: Dalafave D.S.
Published: November 2010

New druglike small molecules with possible anticancer applications were computationally designed. The molecules formed stable complexes with antiapoptotic BCL-2, BCL-W, and BFL-1 proteins. These findings are novel because, to the best of the author's knowledge, molecules that bind all three of these proteins are not known. A drug based on them should be more economical and better tolerated by patients than a combination of drugs, each targeting a single protein. The calculated drug-related properties of the molecules were similar to those found in most commercial drugs. The molecules were designed and evaluated following a simple, yet effective procedure. The need for substantial computational resources often precludes researchers in many countries and small institutions from participating in the field. The procedure presented here offsets the problem by reducing the cost of involvement. The procedure can be used efficiently in the early phases of drug discovery to evaluate promising lead compounds in time- and cost-effective ways.
A Novel Strategy for Mechanism Based Computational Drug Discovery
Authors: Subha Kalyaanamoorthy , Kumar Gopal Ramesh , Rajalakshmi Rajasekaran , Aravindhan Ganesan
Published: November 2010

Glioma, the common brain tumor, which arises from the glial cells, offers worse prognosis and therapy than any other tumors. Despite the genetic and pathological diversities of malignant gliomas, common signaling pathways that drive cellular proliferation, survival, invasion and angiogenesis have been identified. Very often, various tyrosine kinase receptors are inappropriately activated in human brain tumors and contribute to tumor malignancy. During such tumourous states where multiple pathways are involved, a few of them are responsbile for cell differentiation, proliferation and anti-apoptosis. Computational simulation studies of normal EGFR signaling in glioma together with the mutant EGFR mediated signaling and the MAPK signaling in glioma were carried out. There were no significant cross talks observed between the mutant EGFR and the MAPK pathways and thus from the simulation results, we propose a novel concept of ‘multiple-targeting’ that combines EGFR and Ras targeted therapy thereby providing a better therapeutic value against glioma. Diallyl Disulfide (DADS) that has been commonly used for Ras inhibition in glioma was taken for analyses and the effect of inhibiting the EGFR downstream signaling protein with this DADS was analyzed using the simulation and docking studies.
Differential Transcriptional Changes in Mice Exposed to Chemically Distinct Diesel Samples
Authors: Stevens Tina , Hester Susan , Gilmour M. Ian
Published: November 2010

Epidemiological studies have linked exposure to ambient particulate matter (PM) with increased asthmatic symptoms. Diesel exhaust particles (DEP) are a predominant source of vehicle derived ambient PM, and experimental studies have demonstrated that they may have adjuvant potential when given with an antigen. We previously compared 3 DEP samples: N-DEP, A-DEP, and C-DEP in a murine ovalbumin (OVA) mucosal sensitization model and reported the adjuvant activity to be: C-DEP ≍ A-DEP > N-DEP. The present study analyzed gene expression changes from the lungs of these mice. Transcription profiling demonstrated that all the DEP samples altered cytokine and toll-like receptor pathways regardless of type, with or without antigen sensitization. Further analysis of DEP exposure with OVA showed that all DEP treatments altered networks involved in immune and inflammatory responses. The A- and C-DEP/OVA treatments induced differential expression of apoptosis pathways in association with stronger adjuvant responses, while expression of cell cycle control and DNA damage pathways were also altered in the C-DEP/OVA treatment. This comprehensive approach using gene expression analysis to examine changes at a pathway level provides detailed information on events occurring in the lung after DEP exposure, and confirms that the most bioactive sample induced many more individual genes and changes in immunoregulatory and homeostatic pathways.
Validation of a Blood-Based Laboratory Test to Aid in the Confirmation of a Diagnosis of Schizophrenia
Authors: Schwarz Emanuel , Izmailov Rauf , Spain Michael , Barnes Anthony , Mapes James P. , Guest Paul C. , Rahmoune Hassan , Pietsch Sandra , Leweke F. Markus , Rothermundt Matthias , Steiner Johann , Koethe Dagmar , Kranaster Laura , Ohrmann Patricia , Suslow Thomas , Levin Yishai , Bogerts Bernhard , van Beveren Nico (JM) , McAllister George , Weber Natalya , Niebuhr David , Cowan David , Yolken Robert H. , Bahn Sabine
Published: November 2010

We describe the validation of a serum-based test developed by Rules-Based Medicine which can be used to help confirm the diagnosis of schizophrenia. In preliminary studies using multiplex immunoassay profiling technology, we identified a disease signature comprised of 51 analytes which could distinguish schizophrenia (n = 250) from control (n = 230) subjects. In the next stage, these analytes were developed as a refined 51-plex immunoassay panel for validation using a large independent cohort of schizophrenia (n = 577) and control (n = 229) subjects. The resulting test yielded an overall sensitivity of 83% and specificity of 83% with a receiver operating characteristic area under the curve (ROC-AUC) of 89%. These 51 immunoassays and the associated decision rule delivered a sensitive and specific prediction for the presence of schizophrenia in patients compared to matched healthy controls.
Decreased Serum Hepatocyte Growth Factor (HGF) in Individuals with Depression Correlates with Severity of Disease
Authors: Russo A.J.
Published: November 2010

Aim

To assess serum Hepatocyte Growth Factor (HGF) levels in individuals with depression and to test the hypothesis that there is a relationship between severity of depression and HGF concentration.

Subjects and methods

Serum from 26 clinically depressed individuals and 19 controls were tested for serum HGF using ELISAs. Correlation was established between HGF concentration and disease severity.

Results

Depressed individuals had significantly lower serum levels of HGF compared to controls ( P < 0.0001). HGF concentration correlated with overall depressive behavior ( P = 0.03) and specifically depression ( P = 0.02), but not anxiety ( P = 0.36).

Discussion

These results suggest an association between HGF serum levels and clinically depressed individuals and demonstrate a correlation between severity of depression and HGF levels. Further studies of the predictive strength of HGF as a biomarker for depression may be warranted.