bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of the Thermal Error Robust Modeling of 2-Axes Machine Tools Based on the Grey System Theory
Authors: Wang Xiu Shan , Yan Li , Wang Ling , Kong De Jun
Published: January 2010

Thermally induced errors can contribute as much as 70% of the final error of the part dimensions produced on machine tools [1-5]. Thermal errors of machine tools can be treated as the superposition of a series of the errors coming from different heat source. 4 key temperature points of a turning lathe were obtained based on the temperature field analysis. A novel thermal error model on the basis of grey system theory was proposed. The basic principle and method of grey system model and its application in thermal error modeling on machine tools had been presented briefly.
Applying Artificial Neural Network Model on Investigating the Fiber Diameter of Polybutylene Terephthalate (PBT) Spunbonding Nonwovens: Comparison with Mathematical Statistical Method
Authors: Zhao Bo
Published: January 2010

In this paper, two models are founded and introduced to predict the fiber diameter of polybutylene terephthalate spunbonding nonwovens from the spunbonding process parameters. The results indicate the artificial neural network model has good approximation capability and fast convergence rate, and it can provide quantitative predictions of fiber diameter and yield more accurate and stable predictions than the mathematical statistical method. This area of research has great potential in the field of computer assisted design in spunbonding technology.
An Ontology-Based Design Knowledge Model
Authors: Tang Guo Xing , Guo Hun , Jin W.D.
Published: January 2010

In this paper, we investigated the knowledge modeling and proposed an ontology-based representation approach in order to support the management and re-usage of the knowledge of design. We also established the methods to classify and present the concept-design knowledge and developed an ontology-based model presenting the knowledge of design.
Finite Element Simulation of Ti-6Al-4V Three-Dimensional Milling
Authors: Zhao Y. , Xu Feng , Zuo Dun Wen , Kang Jing
Published: January 2010

In this paper, by adopting an equivalent geometry model of the cutting layer, a three-dimensional (3D) finite element model was built to investigate the milling of Ti-6Al-4V. The chip separating process was simulated by Arbitrary Lagrangian-Eulerian (ALE) method and automatic re-meshing technology. The experiments of milling Ti-6Al-4V were carried out to verify finite element model of milling process. The comparisons of the predicted cutting forces and the measured forces showed reasonable agreement. Finally, the finite element model was used to predict the chip deformation and the three-dimensional distribution of cutting force, stress and temperature in milling Ti-6Al-4V.
An Artificial Neural Network Approach to Predict the Relationship between the Processing Parameters and Properties of TC21 Titanium Alloy
Authors: Chen Ming He , Li J.H. , Zhu Zhi Shou
Published: January 2010

This paper develops a three-layer back-propagation artificial neural network model to analyze and predict the correlation between processing parameters and properties of the damage tolerance type titanium alloy TC21. The inputs of the ANN are working temperatures, deformation extent, deformation rate and heat treatment conditions. And the outputs are mechanical properties namely ultimate strength, yield strength, elongation, reduction of area, plane strain fracture toughness and microstructure concerned parameters such as β phase fraction, βphase grain size, substructure length and thickness. The ANN is trained with experimental data and achieves a very good performance, which has already been applied to the optimization of processing for forging of aero-parts.
Relationship between the Fine Discharge Parameters and Craters EDMed of the NAK80 Steel
Authors: Wang Hong Jun , Zuo Dun Wen , Wu X.M. , Wang M.
Published: January 2010

The crater diameter and depth of the surface machined by electrical discharge machining (EDM) were used to evaluate indexes for EDMed surface. The influence of discharge parameters selected on the crater diameter and depth in mirror-like surface EDM process was investigated, and the optimization scheme was obtained. An L16 (44×23) Taguchi standard orthogonal array was chosen for the design of experiments. Experimental results indicate that peak current and open discharge voltage have more influence on the crater diameter and depth in comparison with pulse off-time and pulse duration. Also the results confirm that the crater depth is about 10 to 20 percent of its diameter while the near-mirror EDM conducted in the NAK80 steel with fine discharge parameters.
Self-Assembled Optical Gratings with Banana-Shaped Liquid Crystals
Authors: Huang Yuan Ming
Published: January 2010

We demonstrated that a homologous series of banana-shaped liquid crystals, 1,3-phenylene bis(4-alkyloxybenzylideneamine), could assemble themselves into various kinds of groove-free diffraction gratings when their isotropic melts were slowly cooled into mesophases between two pieces of glass substrates. The groove-free diffraction gratings included one-dimensional parallel gratings, two-dimensional crossed gratings, two-dimensional fan-shaped gratings and two-dimensional circular gratings. Characterization by means of polarized optical microscopy showed that a pattern of periodic modulation of the refractive index was developed in the thin films formed by the banana-shaped compound. Our laser light diffraction experiments confirmed that these groove-free gratings could effectively diffract the incident red light from a helium-neon laser. On the basis of the diffraction equations derived for the self-assembled groove-free optical gratings, the diffraction patterns were simulated for the parallel gratings, orthogonally crossed gratings, fan-shaped gratings and circular gratings, respectively, and good agreement was achieved. The mechanisms on the self-assembly of the banana-shaped molecules were discussed in terms of intermolecular interactions. Our work provides an alternative method for manufacturing diffraction gratings by harnessing the self-assembly of banana-shaped molecules.
Influence of the Terminal Substituent of Azobenzene on the Liquid Crystalline Property of ABA Triblock Copolymers
Authors: Tang Xin De , Gao Long Cheng , Han Nian Feng
Published: January 2010

The influence of the terminal substituent of azobenzene on the liquid crystalline property of ABA triblock copolymers was studied. Three kinds of azobenzene-containing monomers with different terminal substituents were respectively used to synthesize ABA triblock copolymers (denoted as PMMAzo12-PEG13-PMMAzo12, PEMAzo14-PEG13-PEMAzo14, and PNMAzo14-PEG13-PNMAzo14) by atom transfer radical polymerization (ATRP). These copolymers were characterized with 1H NMR and GPC, and exhibited controlled molecular weights and narrow molecular weight distributions. Differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) have shown that these copolymers have mesophases. PMMAzo12-PEG13-PMMAzo12 has a smectic mesophase and a nematic mesophase, while both PEMAzo14-PEG13-PEMAzo14 and PNMAzo14-PEG13-PNMAzo14 have a nematic mesophase. This demonstrates that the LC properties of these copolymers highly depend on the terminal substituent of azobenzene.
Bimetallomesogens: Synthesis and Mesomorphic Properties of Coppercomplexes of 3,3'-(2-hydroxypropane-1,3-diyl)bis(azan-1- yl-1-ylidene)bis(2-(4-alkoxyphenyl)prop-1-en-1-ol)
Authors: Chen Chung Jung , Lai Chung K.
Published: January 2010

A new type of 3,3'-(2-hydroxypropane-1,3-diyl) bis(azan-1-yl-1-ylidene)bis(2-(4-alkoxy phenyl)prop-1-en-1-ol) and their copper complexes were prepared and mesomorphic properties characterized. The mesomorphic properties of these copper complexes were studied by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and powder X-ray diffraction. X-ray structural crystallographic analysis showed that these bimetallic compounds have two copper centers coordinated with central square planar geometry. These molecules all have total two 1a or five alkoxy sidechains 1b appended around the central core. The mesomorphic behavior exhibited was found to be dependent on the sidechain density. All compounds in 1a exhibited smectic mesophases, however, compounds in 1b exhibited hexagonal columnar phases (Colh), which were characterized by optical textures and confirmed by powder x-ray diffraction.
Purple Photoluminescence from Banana-Shaped Molecules 1,3-Phenylene bis(4-methoxybenzylideneamine)
Authors: Huang Yuan Ming , Zhai Bao Gai
Published: January 2010

The optical absorption and photoluminescence spectra of banana-shaped molecules 1,3-phenylene bis(4-methoxybenzylideneamine) have been investigated with an ultraviolet-visible spectrometers and a spectrofluorometer, respectively. The optical characterizations indicate that the banana-shaped molecules exhibit strong absorptions in a broad range of 260-370 nm and that they can give off strong purple photoluminescence when excited by ultraviolet photons. Using Hückel tight-binding program, we have calculated the electronic structures of the banana-shaped molecules. In light of the calculated electronic structures, the origin of the purple photoluminescence is discussed, and our results have demonstrated that not only the lowest unoccupied molecular orbital and the highest occupied molecular orbital but also the localized energy levels of the lone pairs are responsible for the recorded purple photoluminescence.
Bistable Technology in Flat Panel Display: Principle and Progress
Authors: Huang Zi Qiang
Published: January 2010

Active matrices often related with high grade display devices, due to application of the storage elements, typically thin film transistor (TFT). Because of the complex procedures in the manufacturing TFT, investment of the high value manufacturing equipments and clarification plants is necessary, hence increasing the manufacturing cost of the flat panel, and more importantly, causing the pollution of water and air. As the contribution of TFT array merely exists in supplying storage function for the pixels of the display panel, large efforts have been made to find suitable cells that have bistable effect, so as to substitute the effect of TFT. As the bistable cell is just the storage pixel, one could construct a bistable cell to skip the needs of TFT active matrices. The paper is to introduce currently available bistable display devices in the following field: liquid crystal bistable displays with cholesteric liquid crystals, which is an example to introduce the bistable technology; iMod display devices based on mechanic induced bistable and light interference, which shows the possibility to construct bistable display; and the display based on solid powder movement in air or in vacuum, so called liquid powder displays, which shows how to improve the existed display.
Periodically Birefringent Thin Films Grown out of the Isotropic Phase of a Bent-Core Banana-Shaped Liquid Crystal
Authors: Ma Qing Lan , Huang Yuan Ming
Published: January 2010

Periodically birefringent thin films growing out of the isotropic phase of the banana-shaped liquid crystal 1,3-phenylene-bis (4-butoxybenzyldiamine) were investigated with polarized optical microscopy. The gown thin films of the periodic modulation of the birefringent index self-assembled by the banana-shaped LC molecules were attributed to the difference of the molecular composing structures. Further the driving forces of the banana-shaped molecular self-assembly were discussed.
Liquid Crystalline Behavior of Mixture of Two Non-Mesogenic Compounds
Authors: Mahadeva J. , Nagappa
Published: January 2010

The lyotropic liquid crystalline behavior of N-Cetyl-N, N, N, Trimethyl Ammonium Bromide (CTAB) with ethylene glycol (EG) has been investigated. These compounds are non-mesogenic in nature and exhibits Sm A, Sm B and Sm G phases. The stability of the phases is investigated using X-ray diffraction and optical studies. The layer thickness and molecular length are calculated using Bragg’s equation. The interfacial area per polar group and average thickness of hydrocarbon layers are estimated for different concentrations of the mixtures at different temperatures.
Optical Switching Properties of an Azo-Containing Banana-Shaped Liquid Crystal
Authors: Huang Yuan Ming , Zhai Bao Gai
Published: January 2010

By triangular wave method, the switching currents of an azo-containing banana-shaped antiferroelectric liquid crystal were investigated as a function of temperature. As the temperature increases from 150 to 175oC, the switching currents of the banana-shaped liquid crystal were observed to decrease linearly with the temperature. The unusual temperature-dependent polarization was discussed in the light of Landau-de Gennes theory.
Effects of Cyclic Heating and Cooling on the Banana-Phase Growing Behaviors of Banana-Shaped Liquid Crystal 1,3-Phenylene-bis[4-(4-octyl phenylimino)methyl]benzoate
Authors: Huang Yuan Ming , Ma Qing Lan , Zhai Bao Gai
Published: January 2010

The effects of cyclic heating and cooling on the banana-phase growth behaviors of the prototype banana-shaped liquid crystal 1,3-phenylene-bis[4-(4-octylphenylimino)methyl]benzoate were investigated with differential scanning calorimetry and polarized optical microscopy, respectively. Cyclic heating and cooling can reduce the phase transition temperatures and increase the domain sizes of the banana phases of the banana-shaped liquid crystal. These results can be interpreted in terms of the nucleation and growth of the banana phases out of its isotropic phase of the banana-shaped liquid crystal.
Half-Buried Structure Cu Bus Line in TFT LCD
Authors: Ning Hong Long , Jeong Chang Oh , Song Ki Yong , Cho Sung Hen , Kim Jae Hong , Yang Dong Ju , Song Jean Ho , Kim Shi Yul
Published: January 2010

As we know, we normally used stacked aluminum bus line as the Gate or Source/Drain layer in LCD now, but the next general LCD needs larger display area, higher resolution, and faster response time, so we need develop the new TFT bus line structure and select the appropriate metallization materials to decrease the resistance of bus line. There are many new kinds of structure and material were used, for example copper, silver and their alloys, pure copper have some advantages among them because of its low electric resistance and cost, but it is restricted by the problem of pure copper’s lifting and etching. In this paper, we not only use electroless copper plating to decrease the resistance and cost of bus line but also use the half-buried structure to increase the thickness of bus line, it can combine these two new technologies well in LCD. We use the half-buried structure copper bus line to make some panel samples, it can decrease the delay of RC greatly (it is lower than 1/4 of normal aluminum bus line panel in the same size).
Synthesis and Properties of UV-Curable Sealant for LCD Panels
Authors: Ma Qing Lan , Huang Yuan Ming
Published: January 2010

Ultraviolet curable sealant was synthesized by polymerizing epoxy resin with acrylic acid in the presence of catalyst N,N-dimethylbenzylamine. The synthesized ultraviolet-curable sealant could be solidified upon exposure to 365 nm ultraviolet irradiation for 8 seconds. The optical, mechanical and thermal properties of the ultraviolet-cured sealant were investigated with ultraviolet-visible spectrometer, tensile machine and differential scanning calorimetry, respectively. Our results demonstrated that the transparent and thermally stable sealant was strong enough for liquid crystal display panels.
Crystallization of Calcium Carbonate Vaterite Involves with another Mechanism Associated with Liquid Crystal in Embryonic Yolk Sacs
Authors: Xu Meng Meng , Jones Odell , Cao Guan Liang , Yan Gui Fang , He Hai Ping , Zhang Chu Yu , Xu Xue Hong
Published: January 2010

Calcium carbonate is often used as an efficient antacid that absorbs and neutralizes stomach acid while providing calcium for healthy bones. Taking advantage of the lack of adverse side effects of calcium, new drug delivery systems consisting of drug-supported spherical microparticles are being developed. We have reported in our previous studies that a natural process producing calcium carbonate microparticles can be found during avian development. These natural systems provide inspiration for designing more efficient microparticle facilitated drug-delivery systems. In this study, the formation and re-absorption of calcium carbonate crystals were tracked during Gallina N. meleagris embryogenesis and early postnatal development. The study demonstrated that the formation of calcium carbonate microparticles, as calcium is transferred from the eggshell into the egg sac, is a process of calcium preservation. X-ray diffraction showed that calcium carbonate crystal is mainly preserved in the vaterite isoform. Calcium incorporated into the yolk sac during this process can be easily assimilated as necessary during postnatal development. Eons of evolution have yielded a calcium preservation process that produces an iso-form of crystalline calcium most readily absorbed by the organism. Our previous results indicate that this biological system is likely a lyotropic process, the method that is currently being used for the production of microparticle drug delivery systems. In this work, our data suggests that calcium carbonate crystal can also initiate its crystallization from the center of liquid crystal, recognizable by a chimeric thermal phase transition. Our work provides valuable information for designing more efficient microparticle for drug-delivery.
Design and Study of Optical Devices Based on Holographic Polymer Dispersed Liquid Crystal Technology
Authors: Zheng Ji Hong , Wen Ken , Gu Ling Juan , Zhuang Song Lin
Published: January 2010

Micro/nanoscale liquid crystal (LC) droplets are dispersed within polymer matrix, known as polymer-dispersed liquid crystals (PDLCs). LC molecules can be reoriented under an applied voltage, which makes PDLC-based devices have wide applications in optical communications, integrated optics, and panel displays, etc. In this paper, we summarized our work on holographic PDLC (H-PDLC) devices including variable attenuators, dynamic gain equalizers and focus-switchable lenses. More importantly, a specially designed H-PDLC chopper array was demonstrated, which will be applied in the new-born frequency division multiplexed high-speed fluorescence confocal microscope system.
Study on Shape Memory Effects of LC Epoxy Resins with Lateral Substituents
Authors: Liang Li Yan , Zhou De Wen , Lu Man Geng
Published: January 2010

A series of shape memorized liquid crystalline epoxides with different length of lateral substituents were prepared with several kinds of hardener. The dynamic mechanical analysis and the sharp memory properties of the resulted LC epoxy resins were studied by POM, WAXD, DSC and DMA. The results showed that the modulus in the rubbery region (ER) of the LC epoxides decreases as the length of lateral alkyl groups increases. And the shape memory properties were strongly impacted not only by the length of lateral substituents, but also by the kinds of hardener. The recovering speeds of the shape-memory liquid crystalline epoxides decrease as the increasing length of lateral alkyl groups. And recovering speeds of LC epoxides cured with aromatic amine (DDM) are faster than that of LC epoxides cured with anhydride (THHPA). The local ordered structures and the lateral substituents played an important role in shape memory effects.
A Color Management Model for Color Sensors of Liquid Crystal Display
Authors: Li Xin Wu
Published: January 2010

Color management for liquid crystal display is one of the key techniques in the color image reproduction. A new color management model is presented based on overcoming flaws and limitations of current ways of liquid crystal display color management . First, the paper takes standard color target for experimental sample, and substitutes color blocks in color shade district for complete color space. Second, data collecting method is introduced and some data bases for deducing the model are created. Then, ant colony algorithm is corrected to speed up model’s convergence and a new model for liquid crystal display color management based on improved ant colony algorithm is deduced and analyzed. Finally the experimental results show that the model can improve color management accuracy of liquid crystal display and can be used in its color management practically.
Synthesis and Mesomorphism of Rigid Bridge Triphenylene Discotic Liquid Crystal Dimers
Authors: Zhou Hui , Yu Wen Hao , Wang Bi Qin , Hu Ping , Zhao Ke Qing
Published: January 2010

Pd-Cu catalyzed homocoupling reaction has been used for the synthesis of symmetrical triphenylene discotic liquid crystal dimers, [C18H6(OCnH2n+1)5(O2CC6H4C≡C-)]2 (n = 4, 5, 6, 7, 8, 9), which connected two triphenylene discogens via a long rigid spacer. The purity and structure of monomers and dimers have been characterized with 1H NMR, IR and high resolution Mass. Their fine thermal stability has been confirmed by the results of thermogravimetry analysis (TGA). Polarized optical microscopy (POM) and differential scanning calorimetry (DSC) results have shown that the monomers and dimers exhibit columnar mesophases (Col). The dimers display wide mesophase ranges and are room temperature liquid crystals, and their clearing points increased with the lengthening of peripheral alkyl chain.
Design and Realization of the Data Collecting System Based on USB Bus Line
Authors: Fu Xiao Guang , Wang Xiao Jun
Published: January 2010

Universal serial bus (USB) is a kind of new bus interface specification, whose characteristics are convenience, high speed, easiness to expand, low cost and low disturbance, etc. So it is extremely fit to be the communication interface between host computer and peripherals. This paper is mainly about the development of data collecting system based on of USB, including hardware design, firmware design, equipment driver programming and application software design based on Windows driver model (WDM). This system works stable. Both the sampling precision and the data transmission speed have reached expected effect.
Organic Photovoltaic Cells Prepared with Toluene Sulfonic Acid Doped Polypyrrole
Authors: Zhou Fu Fang , Pan Chun Xu , Huang Yuan Ming
Published: January 2010

Organic photovoltaic cells were fabricated by sandwiching p-toluene sulfonic acid doped conducting polymer polypyrrole between indium-tin-oxide cathodes and aluminum anodes. The active polymeric layers could effectively absorb incident photons more than 75 % in the entire spectral region of 250~1100 nm. Upon light exposure, the short-circuit current and the open-circuit voltage were recorded up to 0.6 μA/cm2 and 60 mV, respectively, for the organic photovoltaic cells. The dynamics of the generation and decay of the photocurrent and photovoltage in our organic photovoltaic cells were investigated.
Study on the Triode FED Device with the Improved Insulator
Authors: Li Yu Kui , Li Xiao Jun
Published: January 2010

Carbon nanotubes used as field emitters, the field emission display with improved insulator was reported. The fabrication process of improved gate structure with the mica plate as insulator between gate-electrode and cathode was presented. The technical development in the design of the improved insulator was also given. The patterned silver slurry was used to form the gate electrode and the screen-printed insulation slurry was formed the gate cover layer. The sealed field emission display packaged by the vacuum-device process had been developed and demonstrated. The modulation of electron emission by the gate voltage was also confirmed. The whole flat display device possessed better field emission properties and high brightness.
Growth of ZnO Films under Different Oxygen Partial Pressures by Metal Organic Chemical Vapour Deposition
Authors: Wang C. , Yang X. , Liu B. , Zhao C. , Tang W. , Yang J. , Gao X. , Liang H. , Zhao Jie , Sun J. , Du G.
Published: January 2010

ZnO films were grown under different oxygen partial pressures by metal organic chemical vapor deposition on the substrates of Corning glass. We investigated the quality of the films by SIEMENS D8 X-ray diffractometer. The surface morphology of the films were observed by Digital Nanoscope ІІІa AFM with normal silicon nitride tip in the contact mode. The hall effect measurements were carried out with indium ohmic contact. The transmission spectrum of the films were measured. The transmission ratio is larger than 80% in the region above the wavelength of 385nm, and sharply decreased under 10% below the wavelength of 375 nm.
Green Synthesis of Liquid Crystal Intermediates the Preparation of Phenylacetylenes in Ionic Liquids
Authors: Liu Bao You , Yang Hui Long , Wang Yi Ping , Wang Yuan Yuan , Wu Zhi Jie , Wei Fu Xiang
Published: January 2010

Sonogashira coupling of phenylacetylenes with phenyl iodides in 1-butyl-3-methyl- imidazolium bromide (BMImBr) was explored. Using CuI/Pd(PPh3)4 as a catalyst and Im as the base, the expected substituted acetylenes were obtained with good to excellent yields (61%-95%) under mild conditions (4h, 60oC). After the product was isolated, the left ionic liquid can been readily recovered and reused in the subsquent runs with almost the same efficiency. The reactivity of different iodoarenes with terminal alkynes was also discussed.
Extraordinary Transmission through Periodic Arrays of Subwavelength Metal by Coating
Authors: Han Guang Cai , Wang Ya Wei , Deng Xiao Bin , Wang Li Feng , Lei Hai Na , Liu Ming Li
Published: January 2010

In this paper, some virtuallab experiments have been done, in which the we get extraordinary transmission phenomenon by adding dielectric coating in the subwavelength periodic metallic slits. It is proved that dielectric coatings on the metal films can excite a surface wave which is transmitted in the metal slits by dielectric waveguides, and the symmetric wrapped dielectric cladding around the metal gains almost 10 times as great transmission as two surfaces cladding does. The paper explores a preliminary physics mechanism of this extraordinary transmission, which gets some valuable results in the application fields.
Self-Similarity of Electrochemically-Deposited Copper Films on Porous Silicon
Authors: Chen Lan Li , Zhai Bao Gai , Huang Yuan Ming
Published: January 2010

The microstructures of electrochemically-deposited copper control electrode on semiconducting porous silicon films were investigated with scanning electron microscopy. Our results showed that smooth control electrode could be grown in areas far from the edge of porous silicon film while irregular electrode was formed on the circular edge of porous silicon films. The self-similarity of the electrochemically-deposited copper control electrode was analyzed in details.
FeSiB Annealing Technology Based on Amorphous Ribbons of the Linear Expansion Coefficient
Authors: Huang Chun Ying , Wan Man Hua , Wang Xiao Jun
Published: January 2010

The 4.5mm wide 25μm thick Fe78Si9B13 amorphous alloys were prepared by single-roller method, and it was annealed. The elastic modulus, tensile deformation and line expansion coefficient were investigated by Q800 (dynamic mechanical thermal analyses, DMA). The results showed that the elastic modulus, tensile deformation and line expansion coefficient were enhanced when annealed. Comparing with the annealed ribbons, the change rules of elastic modulus, tensile deformation and line expansion coefficient of the quenched are evident, that the elastic modulus decreases and tensile deformation increase with temperature increases, but line expansion coefficient firstly increase then decrease with temperature increases.
Size-Dependent Conductivity of Polypyrrole Doped with Anthraquinone-2-Sulfonic Acid Sodium
Authors: Zhou Fu Fang , Zhai Bao Gai , Pan Chun Xu , Huang Yuan Ming
Published: January 2010

By varying the dopant-to-monomer ratio in a wide range of 0―110%, a series of polypyrroles doped with 9,10-anthraquinone-2-sulfonic acid sodium were synthesized by polymerizing the monomer pyrrole in aqueous solution of ferric chloride. The resulted polypyrroles were characterized with the four-probe, laser light scattering and differential thermal analysis, respectively. Our results indicated that the average particle size dominates the change in conductivity and thermal stability for the resulted polypyrrole at different dopant concentration.
Conductivity and Thermal-Stability of 5-Sulfosalicylic Acid Sodium Doped Polypyrrole
Authors: Zhou Fu Fang , Zhai Bao Gai , Pan Chun Xu , Huang Yuan Ming
Published: January 2010

By varying the dopant-to-pyrrole ratio in a wide range from 0 to 60% a series of 5-sulfosalicylic acid sodium doped polypyrrole was synthesized in situ in aqueous solution with ferric chloride as the oxidant. The resulting polypyrroles were characterized with the four-probe, laser light scattering and thermo-gravimetry analysis, differential thermal analysis, respectively. Our results indicate that the particle size plays a determinative role to tune the conductivity in the studied range of dopant concentration; and this series of polypyrrole with size-tuned-conductivity exhibits little less thermal-stability although its size and conductivity changes simultaneously and acutely with the dopant concentration. The association of the conductivity with particle size was interpreted in terms of a theoretical model proposed by Baughman and Shacklelette.
Effect of Spacer Length on the Liquid Crystalline Property of Azobenzene-Containing ABA-Type Triblock Copolymers via ATRP
Authors: Tang Xin De , Gao Long Cheng , Han Nian Feng
Published: January 2010

The effect of flexible spacer length on the liquid crystalline property of ABA-type triblock copolymers containing azobenzene groups was investigated. For the study, the monomers, n-[4-(4-ethoxyphenylazo)phenoxy]alkyl methacrylates with varying methylene groups (n = 0, 2, 6) were used to synthesize a series of azobenzene-containing amphiphilic triblock copolymers PAnC-PEG-PAnC by atom transfer radical polymerization (ATRP). Differential scanning calorimetry (DSC), polarizing optical microscopy (POM), and one-dimensional X-ray diffraction (1D WAXD) have shown that the glass transition temperatures of these copolymers decreased as n increases. PA0C-PEG-PA0C has no mesophase, while both PA2C-PEG-PA2C and PA6C-PEG-PA6C have a nematic mesophase. These differences derive of the length of spacer groups between the polymer main chain and side chain.
Preparation of the Polylactide Copolymer by Surface Grafting with Microspheres
Authors: Jin Yu Shun , Xiao Fei , Guo Wen Li , Li Shu Xin
Published: January 2010

The microsphere copolymer [poly(St-co-HEMA)] of monodispersed styrene and 2-hydroxyethyl methacrylate(HEMA) was synthesized by suspension polymerization. New type of hydrophobic microsphere was synthesized by surface grafting polylactic acid using the hydroxyl-terminated of poly (St-co-HEMA) as initiator. The microspheres’ structures and properties were characterized by FT-IR, SEM and thermogravimetric analysis. The results have demonstrated that the copolymer [poly(St-co-HEMA)] is a random copolymer. The volume of the polylactide which was grafted with the microspheres can be controlled by changing the amount of microspheres and hydroxyl in microspheres.
Synthesis and Characterization of a Cholesteric Liquid Crystal Cholesteryl Nonanoate
Authors: Huang Yuan Ming , Guo Ye Tang , Ma Qing Lan , Liu Wei Wei
Published: January 2010

A cholesteric liquid crystal cholesteryl nonanoate was synthesized and then characterized by means of differential scanning calorimetry and polarized optical microscopy. As temperature decreased from its clearing point, cholesteric phase was formed for cholesteryl nonanoate and accompanied by continuous evolution of colors in the focal conic textures. Furthermore, beautiful spherulite crystals were observed to grow out of the cholesteric phase as the crystallization continued. The evolution of the colors in recorded textures was contributed to temperature-dependent selective reflection of the liquid crystal.
Synthesis and Characterization of Hyperbranched Liquid Crystalline Polymer
Authors: Zhang Chen Xi , Lu Shao Rong , Ban Jian Feng
Published: January 2010

Hyperbranched liquid crystalline polymer (HLCP) were prepared by pentaerythritol with 1,2,4-benzenetricarboxylic anhydride(BTCA) and p-hydroxy benzoic acid. The thermotropic properties, the melting point (Tm) and the isotropization temperature (Ti) of the synthesized HLCP were characterized by differential scanning calorimetry (DSC), fourier transform infrared spectroscopy (FTIR) and polarizing optical microscopy (POM). It showed that the new reactive thermotropic liquid polymer containing polyester mesogenic units exhibited thermotropic liquid crystalline properties between 140°C and 230°C.
Structure and Properties of Nickel Aluminide Layers on INCONEL 100
Authors: Sitek R. , Matysiak H. , Ferenc-Dominik Julia , Kurzydlowski Krzysztof Jan
Published: January 2010

The paper presents the results of investigations into the structure and properties of Ni-Al diffusion layers produced on INCONEL 100 by Chemical Vapour Deposition (CVD). The process was carried out in aluminium chloride (AlCl3) mixed with hydrogen atmosphere. The as-deposited layers were subjected to thermal treatment in vacuum to optimize their adhesion, hardness and temperature-resistance. Microstructural characterization of the coatings was carried out by scanning electron microscopy (SEM) The chemical composition was measured via EDS and the phase content was investigated by X-ray diffraction XRD. The resistance to high temperature of the coatings at atmospheric pressure was tested by applying 24-hours cycles at 950 °C. Scratch-tests provided data on the microhardness and adhesion of the coatings. The results indicate that the layers produced on the INCONEL 100 exhibit a very good adhesion combined with exceptional corrosion resistance at high temperatures.
Evaluation of Metallic Corrosion Caused by Alcohol Fuel and Some Contaminants
Authors: Monteiro M.R. , Ambrozin A.R.P. , Santos A.O. , Contri P.P. , Kuri S.E.
Published: January 2010

In the present work, it is evaluated the effect of water and other contaminants of alcohol fuel on the corrosion behavior of different materials, which can constitute vehicles, storage and transportation fuels systems. For such, 5 metallic materials (zamak, low-carbon steel, stainless steel, and two Al alloys) were chosen and 5 alcoholic solutions were prepared: anhydrous ethanol (AEAC; solution 1); hydrated ethanol (AEHC; solution 2); AEAC and water with some impurities (AEAC + 6 % “corrosive” water; solution 3); AEHC and water with some impurities (AEHC + 6 % “corrosive” water; solution 4); and, AEAC and tap water (AEAC + 6 % tap water; solution 5). The crevice corrosion was investigated in static immersion tests, which were carried out at 50 °C for 2 months. The evaluation of the corrosive process was carried out by visual inspection, weight loss, optic microscopy, and scanning electron microscopy (SEM). Also, some quality parameters of the alcoholic solutions (specific mass, alcoholic content, pH, and conductivity) was analyzed in order to determine the influence of corrosion of the materials on them. The results have shown that crevice corrosion of all materials mostly occurred in solutions 3-5, which had a high amount of water and impurities. Some corrosion rates in such solutions were 90-400 times higher than those obtained in AEAC and AEHC. Among the materials, zamak and carbon steel suffered severe corrosive attack. The physicochemical properties of alcoholic solutions employed in the tests also changed, mainly the increase of pH and conductivity was observed. Therefore, the results demonstrate that the quality control of alcohol fuel is essential in order to avoid the damage of engine parts and storage and transportation systems. Specially, water, sulphate, chloride and acetate content must be monitored.
Some Long Term Corrosion Patterns in Archaeological Metal Artefacts
Authors: Figueiredo E. , Silva Rui Jorge C. , Braz Fernandes Francisco Manuel , Araújo M.F.
Published: January 2010

Long term corrosion phenomena are generally not obtained in laboratorial corrosion experiments. Particular features, such as strong intergranular corrosion, can be an indication of the antiquity of a metallic artefact. In the present study, various corrosion features from several archaeological bronze artefacts, with ages ranging from 2 to 5 millenniums, are examined using optical and scanning electron microscopies. Elemental composition was obtained through micro-EDXRF analyses. Corrosion patterns could, in some occasions, be related to specific thermomechanical treatments performed before burial and, in others, with particular phases present in the artefact.
The Influence of Sodium Molybdate on the Properties of Zn-Ni Layers Obtained by Electrolytic Deposition
Authors: Wykpis Katarzyna , Budniok Antoni , Łągiewka Eugeniusz
Published: January 2010

This study was undertaken in the aim to try the limit of extraction of Zn from Zn-Ni system. The aim was realized by the addition of MoO42- ions into the galvanic bath containing Ni2+ and Zn2+ ions. Zn-Ni-Mo layers were deposited under galvanostatic conditions on (OH18N9) austenitic steel substrate. The influence of Na2MoO4 concentration in a bath on the surface morphology, chemical and phase composition and the corrosion resistance of obtained layers, was investigated. The properties of Zn-Ni-Mo layers were compared to the properties of electrolytic Zn-Ni layer. Structural investigations were performed by the X-ray diffraction (XRD) method. The surface morphology and chemical composition and surface chemical elements distribution of deposited layers were studied using a scanning electron microscope. Electrochemical corrosion resistance investigations were done by classical Stern method and electrochemical impedance spectroscopy. The potentiodynamic curves in the range of  0.05V to the potential of open circuit, were obtained. On the base of these curves the parameters like corrosion potential- Ecor, corrosion current density- icor and the polarization resistance- Rp were determined. These values served as a measure of the corrosion resistance of obtained layers. Results of impedance investigations were presented on the Nyquist Z”= f (Z’) and the Bode log Z = f (log) and  = f (log), diagrams. On the basis on this research, it was exhibited that surface morphology, chemical composition of Zn-Ni-Mo layers are dependent on Mo contents. The optimal content of Na2MoO4 in the bath for the sake of corrosion resistance in 5% NaCl, is found to be 1.2 gdm-3.
Low Energy High Current Pulsed Electron Beam (LEHCPEB) Treatment: An Effective Way for Improving Surface Microstructure and Properties
Authors: Grosdidier Thierry , Zou Jian Xin , Zhang K.M. , Hao Sheng Zhi , Dong Chuang
Published: January 2010

Low energy high current pulsed electron beam (LEHCPEB) is a fairly new technique for surface modifications, including hardening, alloying and formation of metastable phases as well as improvement in wear and corrosion properties. The present contribution gives some new insights on the microstructure modifications encountered at the top surface of HCPEB treated metals. In particular, the potential of the technique for structure modifications associated with the use of the pulsed electron beam under “heating” and “melting” conditions are highlighted.
Numerical Simulation and Experimental Analysis of Laser Surface Remelting of AISI 304 Stainless Steel Samples
Authors: Cheung Noé , Larosa M.A. , Osório Wislei R.R. , Lima M.S.F , Lerardi Maria Clara F. , Garcia Amauri
Published: January 2010

The aim of this work is to develop a heat transfer mathematical model based on the finite difference method in order to simulate temperature fields in the laser surface remelting process. Convective heat transfer in the remelted pool is taken into account by using the effective thermal conductivity approach. Experiments of laser surface remelting of AISI 304 austenitic stainless steel samples were carried out in the present investigation, and numerical simulations were applied for the CO2 laser machine operating parameters. The work also encompasses the analysis of microstructural and microhardness variations throughout the resulting treated and unmolten zones. This study permits to conclude that numerical simulation is a useful tool in setting the laser operating parameters, enabling pre-programming of the extent of the treated area.
3D-FEM Simulation and Design Optimization of the Diamond Cutting Tools under Various Loading Conditions
Authors: Li Bin , Amaral Pedro M. , Reis Luís G. , Anjinho Carlos A. , Rosa Luis Guerra , Freitas M.
Published: January 2010

The objective of this work is to develop analysis methods based on 3D-FEM simulations for optimum design of the diamond cutting tools under various loading conditions, considering the sintering process of diamond–metal matrix to originate residual stresses. The work concerns the use of finite element simulation for modelling of thermal residual stresses generated during the sintering process of metal matrix diamond tools normally employed by the industry. Stress distribution fields were determined for the diamond shape using a 4-node, reduced integration ABAQUS solid element type C3D4. The residual stress fields in the nearby region of a diamond particle are examined to study the effects of the sintering temperatures, the stress–strain behaviour of the metal matrix and the compression pressure on the upper surface of the metal matrix. Through the simulations of the cutting forces on the diamond, it is demonstrated that the diamond retention capacity induced by the metal matrix (important for extending the life of a diamond tool) is principally dependent on the sintering process. Optimum design of the diamond cutting tools can be achieved by selecting the appropriate sintering temperatures, the stress–strain behaviour of the metal matrix and the compression pressure on the upper surface of the metal matrix during the sintering process.
Taguchi Analysis of the Effect of Process Parameters in Friction Stir Welding
Authors: Louro Rui , Almeida Leitão Carlos Miguel , Gouveia Helena , Loureiro Altino , Rodrigues Dulce Maria Esteves
Published: January 2010

The task of obtaining suitable welding parameters for the friction stir welding process is often a difficult one, due to the lack of published data and the fact that the exact mechanism by which the process operates has not yet been fully determined. Therefore, suitable welding parameters often need to be obtained by using extensive, time consuming and expensive experimental methods. The work detailed in this paper pertains to the use of the Taguchi method as a mean to reduce the disadvantages of these experimental methods, more specifically, their cost. The Taguchi method accomplishes this task by substantially reducing the number of welding trials that are needed to obtain suitable welding parameters. This reduction leads to the parameters being obtained more rapidly and at a substantially smaller cost. In this paper a procedure for applying the Taguchi method to the friction stir welding process is presented as well as its application to the welding of a specific component. The method was applied to the welding of 4mm thick AA5083-H111 plates in a butt joint configuration, which constitutes one of the most common industrial welding scenarios. The purpose of the experimental tests was to maximize the welding speed whilst ensuring an acceptable welding quality. The quality of the welds was determined through visual inspection and tensile and bending tests. The application of the Taguchi method allowed, with a relatively small number of experimental welds, to provide some insight into the manner by which the parameters should be altered in order to optimize the process.
Laser Hardening of XC42 Steel: Numerical Analysis of Quenched Area
Authors: Saavedra E. , Ramil Alberto , López Ana J. , Álvarez J.C.
Published: January 2010

In contrast with conventional tools, laser processing allows hardening of a restricted zone while keeping the structural properties of the steel bulk. This last quality indicates that, in order to verify a laser hardening, only some specific information of the quenched area is required. The aim of this article is to analyse the reliability of finite element numerical simulation by comparing numerical and experimental outcomes. To do that, we define some magnitudes: the maximum width, the real depth of the laser penetration, the maximum hardness and the hardness versus depth profiles (Jominy’s curves). The tests show the good behaviour of the model and how this contributes important information to the choice of the laser parameters.
Characterization of Portuguese Historical Gypsum Mortars: A Comparison between Two Case Studies
Authors: Freire T. , Silva António Santos , Veiga R. , de Brito J.
Published: January 2010

The use of gypsum plaster for interior covering of walls and ceilings in the Portuguese architecture was particularly expressive in the period between the XVIII and the XX century. However, information about this important heritage is almost inexistent, which is leading to a fast loss of important patrimony. In this paper, the results of the characterization of gypsum plaster samples belonging to two buildings from the same historical period (end of the XIX century and beginning of the XX), situated in distant geographical regions of Portugal are presented and discussed. XRD, TGA-DTA, optical microscopy and SEM-EDS observations were used for the chemical and microstructural characterization. Some physical and mechanical properties, such as capillary absorption, dynamic elasticity modulus and compressive strength were also determined and a relationship between the characteristics observed in the samples and the technology associated to their use and application on site, as well as the possible existence of regional influences on all these aspects, are discussed.
Alteration Features of Stones Applied in Underground Metro Stations
Authors: Alves Carlos , Figueiredo Carlos , Figueiredo Paula , Maurício António , Aires-Barros Luís
Published: January 2010

Several types of stones (igneous, sedimentary and metamorphic) are found applied in pavements, stairs and walls of the underground stations of the Lisbon Metropolitan System, Portugal. A field study based solely on non-destructive and non invasive visual inspection of these stations is presented, aiming to identify different transformations of applied stones and discuss its relation with the stone characteristics. This field study has pointed to relevant issues regarding durability of stone materials namely when used in pavements and stairs. The most striking aspect is the frequently marked variable behaviour of stones from a given rock type under the same use conditions, with heterogeneities and discontinuities that seem to cause irregularity from the early stages and further increase with time, having more accentuated consequences (in terms of intensity of surface irregularity) in some types of limestones. The observations collected could be relevant for the discussion of characteristics relevant for the quality control of these materials (namely at the quarry level), including the selection of stones for future substitutions. There is, therefore, the need for a more complete study comprising detailed petrographic studies and laboratory tests both from the applied stones and from the supplying quarries.