bluuebunny/crossref_metadata_2025 huggingface dataset:
CNT-CoO Complex Conductive Agent for the Positive Electrodes of MH/Ni Batteries
Authors: Wu Jian Bo , Yuan Yong Feng , Chen Wei Ping
Published: March 2009

CoO was usually added to the positive electrodes of MH/Ni batteries as the conductive agent. In this paper, well crystallized multi-walled carbon nanotubes (CNTs) with diameter about 10 nm were added to the positive electrodes of MH/Ni batteries together with CoO. During the process of transformation from CoO to CoOOH, a complex conductive network was created with CNTs as the frame. Because of the high conductivity and the excellent tension characteristics of CNTs, the charge-transfer capability of the electrode was improved and the integrality of the complex conductive network was enhanced. The electrochemical measurements indicated that the impedance of the electrode with CNT-CoO complex conductive agent was lessened compared to the electrode with simple CoO agent. Performance tests of the sealed batteries showed that the positive electrodes with CNT-CoO complex conductive agent exhibited higher discharge voltage, improved capacity, modified discharge stability and prolonged lifespan, especially at high current rates.
Preparation for the Hollow Nickel Fibres of the Positive Current Collector by Electroless Plating Technique
Authors: Liu Ju An , Cheng Yan , Zhu Lei , Jian Xu Yu , Wang Zhong , Yu Hai Jun
Published: March 2009

In this experiment, electroless plating method was used to obtain the hollow nickel fibres. Polyacrylonitrile fibres with the diameter about 10μm and 3mm length were chosen as the templates of electroless-plating through screening and optimizing various fibres. Low temperature alkaline solution with the sodium hypophosphite as the reducer was adopted and the optimal parameters were determined. Polyacrylonitrile composite fibres with a dense nickel coating about 5~7 μm thickness were obtained. The plated fibres were then sintered in the air to remove the organic templates. It had been found that the sintering temperature had great influences on the formation of the hollow fibres. The Polyacrylonitrile fibres could not be removed completely at low temperature (300°C), and when the temperature increased to 400°C, no organic fibres could be observed from SEM and the hollow nickel oxide fibres with dense wall were obtained. However, when the sintering temperature further increased to 500°C, great changes had been found, the hollow fibres with brittle porous wall were obtained. A dense and uniform hollow nickel fibres with nickel content higher than 90% were finally obtained after the hydrogen reduction treatment at the temperature of 750°C for 2 hours.
Study on 1/f γ Noise Characterization of Metallic Interconnection Electromigration
Authors: He Liang , Du Lei , Zhuang Yi Qi
Published: March 2009

Metallic interconnection electromigration is a common phenomenon in integral circuit, and it influences circuit reliability seriously as rapid miniaturization of circuit size. Resistance is a traditional electromigration characterization parameter, but it requires strict testing condition, and it is not sensitive to vacancies accumulation at early stage of electromigration. Some recent researches show that noise is very sensitive to metallic thin film electromigration, it can be used as an effective inspect method for electromigration. So noise wais used to characterize damage degree of Al thin film electromigration in this paper., Tthe results showeds both noise amplitude and frequency exponent increased during electromigration process, and when void nucleation occuredhappens, frequency exponent increased sharply. noise can also reflect electromigration degree under different environment temperature. Through comparing with resistance, noise can be proved a better characterization parameter for electromigration
Effect of the Content of Cu on Solderability and Mechanical Properties of Bi5Sb Solder Alloy
Authors: Yan Yan Fu , Feng Li Fang , Guo Xiao Xiao , Tang Kun , Song Ke Xing
Published: March 2009

It is a difficult subject to develop the high temperature solder with thewhose melting point is within 250～450°C in solder field. Bi5Sb solder alloy whosewith the melting point of about is about 280°C is limited for itshas bad solderability and mechanical properties. In the present work, the new BiSbCu ternary alloy wasis preparformed by adding different contents of Cu to Bi5Sb solder alloy to improve its solderability and mechanical properties. Results showed that the effect of adding 0.5～5.0％Cu into Bi-5Sb on the melting point of Bi5Sb solder alloy wais not distinct , but its solderability and mechanical properties weare markedly improved. Compared to the matrix of Bi5Sb, the spreading area of solder alloy wais about 57.8% largbigger and the tensile strength wais about 212.4% highbigger when the content of Cu wais 1.5wt.%. Analysis of tThe microstructure showeds that the needle-like Cu2Sb gradually becaomes shorter and dense along with the increasing of the content of Cu, which can effectaffected the properties of the solder alloy.
Correlation Between Lattice Strain and Energy Gap Bowing of AlxGa1-xN Epitaxial Thin Films
Authors: Zhao Lan , Lu Zheng Xiong , Cheng Cai Jing , Zhao De Gang , Zhu Jian Jun , Sun Bao Juan , Qu Bo , Zhang Xiang Feng , Sun Wei Guo
Published: March 2009

The correlation between the energy band-gap of AlxGa1-xN epitaxial thin films and lattice strain was investigated using both High Resolution X-ray Diffraction (HRXRD) and Spectroscopic Ellipsometry (SE). The Al fraction, lattice relaxation, and elastic lattice strain were determined for all AlxGa1-xN epilayers, and the energy gap as well. Given the type of intermediate layer, a correlation trend was found between energy band-gap bowing parameter and lattice mismatch, the higher the lattice mismatch is, the smaller the bowing parameter (b) will be.
Fabrication and Properties of Large-Area Silicon Nanowire Arrays
Authors: Fang Hui , Wu Yin , Zhu Jing
Published: March 2009

Wet chemical etching with dry metal deposition method has been developed to fabricate large-area aligned silicon nanowire (SiNW) arrays. The combination of nanoclusters Ag film with proper interconnection and interspaces (of about 20 nm thick), and proper temperature during etching (from 20 to 80 °C) is vital to successfully fabricating large-area uniform SiNW arrays. Raman and photoluminescence spectra of the SiNW arrays indicated their potential applications in chemical detection and optical devices ,respectively.
A Novel Inorganic Ion Conductor Electrochromic Device: MoO3/LiAlO2/NiOx
Authors: Yang H.G. , Wang C. , Cui Yi , Zhu Kai Gui , Diao X.G. , Wang H.Y. , Wang Tian Min
Published: March 2009

An all-thin-film glass/ITO/MoO3/LiAlO2/NiOx/ITO device was deposited by magnetron sputtering for electrochromic application. The amorphous MoO3 and LiAlO2 thin films were prepared with the substrate temperature below 0 °C and in O2 and Ar gas pressure. The structure and surface morphology of the films were characterized by x-ray diffraction (XRD) and atomic force microscopy (AFM). It has been found that the amorphous LiAlO2 thin film was a suitable ion conductor for the electrochromic device. The transmittance in the wavelength range of 400-800 nm for the ITO/MoO3/LiAlO2/NiOx/ITO device changed from 14.48 % to 57.68 % by the applied voltage of 7 V. The blue-colored electrochromic property could be observed for the all-thin-film device. The experimental results indicated that such a monolithic system had great potential to be applied in flat-panel displays and smart windows.
Finite Element Simulation of Effects of Process Parameters on Deposition Rate of SiC by Chemical Vapor Deposition
Authors: Sun Guo Dong , Li He Jun , Zhang Shou Yang , Fu Qian-Gang , Cao Wei , Jiao Yan Qiong
Published: March 2009

A two-dimensional mathematical model for deposition behavior of SiC coating on C/C composites in a hot-wall CVD reactor was developed. Deposition rate of SiC was calculated by finite element method and optimized by using an orthogonal L9(3)4 test. The single and coupling effects of process parameters on deposition rate of SiC, including deposition temperature, the flux of mixed gases, the volume ratio of H2 and Ar, and that of MTS and mixed gases, were calculated and discussed. The optimal deposition rate of SiC was obtained.
The Lubrication Properties of Diamond-Like Carbon Coatings in Engine Oil
Authors: Nie Chao Yin , Liu Xiao Kui , Watanabe Hisashi
Published: March 2009

Ti-doped diamond-like carbon(Ti-DLC) coatings and undoped diamond-like carbon(DLC) coatings were synthesized by unbalanced magnetron sputtering using carburized Chromium Molybdenum Steels (SCM415) as substrates. Nanocomposite structure coatings with metal carbides nanocrystals uniformly dispersing in the amorphous carbon matrix were obtained by the optimization of the kinds of doped metals and deposited parameters. This kind of nanocomposite structure permits improved hardness while maintaining a lower residual stress and getting thick coatings. The friction coefficients of Ti doping DLC coatings are relatively lower compared with undoping DLC coatings in engine oil. The analysis on the wear surface of coatings have indicated that: the surface of DLC doped with metal absorbs more elements from the engine oil, which indicates that the doping of metal can improve the affinity of the coating for the engine oil, enhance the formation of lubrication oil films, and reduce the friction coefficient thereby.
Influences of Heat Treatment on Microstructure and Creep Properties of Ti6Al4V Alloy
Authors: Tian Su Gui , Bao Xian Yu , Zhao Zhong Gang , Liu Yang , Chen Li Qing , Liu Xianghua
Published: March 2009

By means of the measurement of creep curves and microstructure observation, the influence of T6 heat treatment on the microstructure and creep properties of the wrought Ti-6Al-4V the alloy has been investigated. The experimental results showed that the microstructure of the wrought alloy consists of the strip-like +  phases, which results in the alloy displaying a higher strain rate and shorter creep life under the test condition of 575 MPa and 400°C. After T6 treatment, the creep life of the alloy at same conditions enhanced to 548 h from 66 h. Microstructure of T6 treated alloy consisted of the primary  and /phases, and signification amount of the bundle-likephase precipitated along the different orientations in the grains, this is a main reason of enhancing creep life of the alloy. During forging, the denser dislocation rows were activated in the local region of the matrix in the alloy. During creep, the deformed mechanism of the alloy was the double orientations slip of  and  dislocations activated on the pyramidal planes in  phase.
Nano Effects of Helium Plasma Treatment Carbon Nanotubes Coating Basalt Filament
Authors: Huang J.N. , Zhang Ying Chen , Wu H.Y. , Qiu Y.P.
Published: March 2009

The plasticity of APPJ treatment on microstructure and tensile deformation of carbon nanotube coating basalt fiber in the dynamic states was investigated by specialized tensile testing at room temperature. With the addition of low-temperature helium plasma treatment, Young's modulus and yield stress changed. It was found that micro-structural parameter such as the activation volume was important descriptors for carbon nanotube coating basalt fiber and inter-phase effect on strength. The different APPJ treatments on the carbon nanotube coating basalt fiber showed the change rate sensitivity. Results revealed that APPJ treatment carbon nanotube coating basalt fiber and the inter-phase would enhance the ductility of basalt at room temperature. From the SEM micrographs, an increase in surface roughness has been observed and the degree of fibrillation decreased after helium and oxygen plasma treatment. Contact angle analysis showed taht the treated Basalt filament had lower contact angles than the untreated one. Based on FTIR results, the change of wettability and surface energy depended the amount of polar functional groups on the fiber surface introduced by the treatments.
Effects of Fiber Surface Treatments on the Moisture Absorption and Interfacial Properties of Natural Fibers and their Composites
Authors: Li Yan , Lv Feng , Deng Hong Xia , Kollmansberger Ronald , Zeng Shan Ying
Published: March 2009

Interfacial properties of four kinds of natural fibers (et. ramie, jute, sisal and kenaf) reinforced phenolic resin were studied by single fiber pull-out test and short beam shear test. Effect of fiber surface treatments on the interfacial properties was evaluated. It showed that interlaminar shear strength (IFSS) was considerably improved after fiber surface treatments, especially after the silane treatment. Concerns about the poor moisture resistance of natural fibers, effects of fiber surface treatments on the moisture absorption behavior of natural fibers were also investigated by gravimetric methods. The results showed that neither fiber surface treatments nor the environmental temperature has effect on the moisture absorption behavior of natural fibers.
New Method for Improving Formability of AZ31B Magnesium Alloy Sheets
Authors: Huang Guang Sheng , Xu Wei , Huang Guang Jie , Li Hong Cheng , Pan Fu Sheng
Published: March 2009

The magnesium alloy sheets have poor plasticity and formability due to their strong (0002) basal texture. In this paper a new method, repeatedly unidirectional bending (RUB), was used to improve formability of the magnesium alloy sheets. The samples were deformed repeatedly by the unidirectional bending at room temperature and annealed. Firstly, RUB route which is the most infection to formability was investigated. There were two RUB route, single surface RUB and reserve surface RUB. The result showed that better formability can be obtained by the reserve surface RUB. Focused on the development of formability of magnesium alloy sheet, the technological parameters, such as RUB passes, radius of support, annealing temperature and holding time, were determined by orthogonal experiment,and hence the optimal RUB process was acquired. Mechanical property of the samples before and after RUB were characterized and compared. After RUB, (0002) basal textural component of cold rolled magnesium alloy sheet was weakened and σb, σ0.2 decreased obviously. The Erichsen values can be considerably enhanced from 3.53mm to around 6.0mm through RUB.The samples were deformed repeatedly by the unidirectional bending at room temperature and annealed. Firstly, RUB route which is the most infection to formability was investigated. There were two RUB route, single surface RUB and
Computer Simulation and Optimization of Equal Channel Angular Extrusion of AZ31 Magnesium Alloy
Authors: Hu Hong Jun , Zhang Ding Fei , Pan Fu Sheng
Published: March 2009

In order to study the influence of die structures and process parameters on ECAE for wrought magnesium alloy AZ31 and obtain optimized process parameters, the three-dimension(3D) new geometric models with different corner angles (90o,120o,135o) and with or without inner round fillets in the bottom die were designed. The simulation results showed that the loads of top dies declined mainly with the corner angles increasing and inner round fillets of the bottom dies manufactured, the bottom die with inner round corner and the corner angle of 90o was propitious to improve the plasticity and deformation homogeneity of the billets.
Deformation Behavior and Dynamic Recrystallization of As-Cast Mg-Y-Nd-Gd-Zr Alloy: A Study with Processing Map
Authors: Zhao Xin , Zhang Kui , Li Xing Gang , Li Yong Jun , Zhang Kang , Li Shi Wei
Published: March 2009

The characteristic of dynamic recrystallization (DRX) in Mg-Y-Nd-Gd-Zr magnesium alloy had been investigated by compression test at temperatures between 523 and 723K and the strain rates ranging from 0.002 to 1s-1with maximum strain of 0.693. The flow behavior was described by a power exponent function. Processing map of this alloy was established on the basis of dynamic material model. Microstructure observations suggested that the peak value of dissipation factor was 0.36 at the temperature of 673K and the strain rate of 1s-1. The map exhibits flow instabilities as two domains, one is at the lower temperatures but higher strain rates, and the other is at higher temperatures and lower strains.The region at an intermediate temperature and a high strain rate is the region of the optimal mechanical working properties.
Damage Evolution Equation of AZ31B Magnesium Alloy during Superplastic Deformation
Authors: Song Mei Juan , Wang Ling Yun , Liu Rao Chuan , Wang Zhi Xiang
Published: March 2009

After superplastic tensile tests and quantitative analysis of cavity volume fraction, the damage evolution equation based on the law of the micro-damage evolution and statistical mechanics was derived out. The characteristic parameters of damage evolvement and critical value of damage variables are achieved from the experiments.
Mechanical Testing and Numerical Simulation of the Fracture Toughness of Magnesium Alloy AM60 under Impact Loading
Authors: Zeng Xiang Guo , Chen Hua Yan , Gao Zhan Hua , Fan Jing Hong
Published: March 2009

The mechanical testing for magnesium alloy AM60 was conducted on an MTS servohydrolic material testing system. In order to examine the effects of impact velocity on fracture toughness, finite element method was applied to compute the impact fracture toughness of AM60 specimens with single notched edge at room temperature. The specimens were impacted by steel balls (Diameter 20 mm) at the velocities of 80m/s, 120m/s and 160m/s. The simulation results well described the effects of impact velocities on fracture toughness. The finite element analysis performed in this work offered an effective method to compute dynamic fracture toughness for engineering applications.
Bonding of AZ91D Mg Alloy and Al Metal with Mg-Al Eutectic Alloy and its Application in Al Coating on AZ91D Mg Alloy
Authors: Li X.R. , Liang Wei , Zhao Xing Guo , Bian L.P.
Published: March 2009

AZ91D magnesium alloy and Al metal were bonded successfully at 450 oC with load of 25 or 31 MPa by using Mg-Al eutectic alloy as the solder in atmosphere. The microstructure of the AZ91D/Al joints was characterized by SEM equipped with EDS, and the bond strength was measured through three-point bending test. It was revealed that reactive diffusion occurred obviously at the jointing part. The diffusion layers are composed of α-Mg + β-Mg17Al12, β-Mg17Al12, γ-Mg2Al3 and α-Al. The average bend strength of AZ91D/Al joints is 24 MPa with maximum value 28 MPa. To demonstrate the potential engineering application of this technology, AZ91D magnesium alloy plate was coated with Al foil and its corrosion resistance was tested. Electrochemical test results showed that the corrosion resistance of Al coated AZ91D magnesium alloy plate was greatly improved compared with the uncoated one.
Preparation of Aluminum-Magnesium Alloys from Magnesium Oxide by Molten Salt Electrolysis Method
Authors: Yang Feng Li , Yang Shao Hua , Wang Zhao Wen , Shi Zhong Ning , Gao Bing Liang
Published: March 2009

Aluminum-magnesium alloys were prepared from magnesium oxide by molten salt electrolysis method. MgF2-BaF2-LiF was taken as electrolysis.Since the density of MgF2-BaF2-LiF was high than aluminum liquid, upload cathode of aluminum liquid was used in the tests. Current efficiency during melting was more than 80%, and the maximum was up to 87.7%. Some amount of magnesium oxide flowed into electrolytic cell. The content of Mg in alloys increased gradually and up to maximum of 18.6%(w) with electrolyzing time. The experiment results revealed that the addition of KCl improved the physical-chemical property of the melten salt.
Removal of Cu2+ from Aqueous Solution by Alkaline-Activated Konjac Glucomannan
Authors: Luo Xue Gang , Liu Feng , Lin Xiao Yan
Published: March 2009

A raw adsorbent of konjac glucomannan was activated at strong alkaline condition. A comprehensive adsorption study of Cu2+ removal from aqueous solution by adsorption was conducted regarding the effects of initial pH, adsorbent dosage, time, temperature and Cu2+ initial concentration. The adsorption data were applied to Langmuir and Freundlich models and their contents were calculated. Thermodynamic parameter enthalpy change (△Ho) showed that physisorption played an important role in Cu2+-loaded alkaline-activated konjac glucomannan system. Experimental data were also analysed in terms of kinetic characteristics and it was found that adsorption followed well pseudo-second-order kinetics. The results obtained showed that the new adsorbent had good efficiency for the removal of Cu2+.
Study on the Technology of the Environment-Friendly Conversion Coating Containing Phytic Acid for Magnesium Surface
Authors: Lin Ji Xing , Niu Li Yuan , Gao Guang Liang
Published: March 2009

An anticorrosion conversion coating on metal magnesium surface was prepared using immersion method in an aqueous solution containing mainly phytic acid. The coating after the preparation could be dry in the air without a rinse process using water in the final stage. Hence there is no discharge of waste water and waste gas in the whole process. Influence of several factors on the anticorrosion performance of coating was tested. And optimal parameters in the coating formation process were obtained from orthogonal test. The results indicated that the coating had better corrosion resistance, when the solution contained 3% phytic acid, and the immersion time is 7 minutes and the PH value was 3.5. The surface conversion coating was characterized by SEM and EDS. The conversion coating is better than the traditional chromate passive film by testing corrosion speed of coatings using hydrogen evolution method. The technology of the environment-friendly conversion coating containing phytic acid has the potential to be a new anti-corrosion technology for magnesium surface.
Microstructures and Properties of Fiber Laser Welded ACM522 Magnesium Alloy Joint
Authors: Liu Jun , Dong Jun Hui , Shinozaki K.
Published: March 2009

The microstructure, mechanical properties, hardness, rules and mechanism of various parameters on formation of weld bead of Mg alloy ACM522 using a fiber laser welding were investigated. The results showed that sound welds without major defects could be produced and the mechanical properties of welding joints were good. With the increase of laser power, the penetration depth and bead width of the weld bead all increased. The mechanism of welding transformed from the conduction welding mode to the deep penetration welding mode and the weld beads aspect ratio became higher with the increase of heat input. The microstructure of weld metal was significantly finer and the hardness of weld metal was higher than that of the base metal.
Research on Grinding Force and Surface Roughness Based on the Abrasive Belt Grinding to Magnesium Alloy
Authors: Huang Yun , Li Xin , Luo Su Qin , Huang Zhi
Published: March 2009

Magnesium alloy matrix quality is important for the quality of coating on the surface, and thus affecting the final performance of magnesium alloy. This paper developed a method to the abrasive belt grinding as a pre-treatment process for magnesium alloy. Based on the orthogonal test in the abrasive belt grinding of magnesium alloy, the effect of the processing parameters on grinding force and roughness has been studied. Finally, a predicting model of the grinding force and surface roughness was established by means of the neural networks. This model was verified from both the theoretical and experimental facets. The results showed that the model can be used to describe the influence of some machine tool inputs
Analysis on the Weld Defects of the AZ91D Magnesium Alloy Joints
Authors: Ye Hong , Yan Zhong Lin , Shen Bin , Xue Z.F.
Published: March 2009

In this study, taking die-cast magnesium alloy AZ91D as investigation objects, the process characteristics of electron beam welding (EBW) was studied. The microstructure and familiar defects in the welded joints were analyzed. The main reasons of these defects were discussed. The experimental results showed that boundary surface between fusion zone and heat affected zone in the joint of AZ91D magnesium alloy by electron beam welding is obvious, the fusion zone (FZ) consisted of fine-equiaxed grain. Pore and crack are the main defects in AZ91D magnesium alloy joints. Magnesium has higher hydrogen solubility in liquid than in solid. The difference in the solubility between the solid and liquid phase is the major reason of the pore of magnesium alloys during welding. The crack was caused because of α + β-Mg17Al12 phase with low melting point and pores in the fusion zone. There were other defects found in the joints such as incomplete fusion and penetration.
Development of Surface Treatment in Industrial Scale for Components with Metallic Luster on AZ31 Sheets
Authors: Ohara M. , Takigawa Yorinobu , Higashi Kenji
Published: March 2009

We have developed a new surface treatment, Mgbright, which produces a luster on AZ31 magnesium alloy surfaces. The treatment consists of a chemical process and a coating process, and the primary characteristics are that of developing a luster on AZ31 magnesium alloy and imparting a high resistance to corrosion. When Mgbright was applied, the value of surface roughness, Ra, required for developing luster was 1.5 µm. As the target Ra value of press-formed articles was set to less than 1.5 µm, mass-production press-forming was tested by means of the 100,000 times square-cup drawing method, and the target was achieved. We applied the Mgbright treatment techniques and the square-cup drawing test, and produced a laptop computer chassis.
Nanostructured 316 Stainless Steel Prepared under Traction by Surface Mechanical Attrition Treatment
Authors: Yang Xiao Fang , Lu Jian
Published: March 2009

A nanostructured 316 austenitic stainless steel sample was prepared under traction using a new surface mechanical attrition treatment (SMAT) system. The microstructure of the surface layer of the SMATed sample was characterized using an optical microscope and transmission electron microscope (TEM). Microhardness on the cross-section was investigated by nanoindentation measurement. Results showed that a deeper nanostructured layer was obtained in comparison with that of the sample SMATed without traction.
Advanced Numerical Simulation of Metal Forming Processes Using Adaptive Remeshing Procedure
Authors: Cherouat Abel , Giraud-Moreau Laurence , Borouchaki Houman
Published: March 2009

This paper presents an advanced numerical methodology which aims to improve virtually any metal forming processes. It is based on elastoplastic constitutive equations accounting for non-linear mixed isotropic and kinematic hardening “strongly” coupled with isotropic ductile damage. During simulation of metal forming processes, where large plastic deformations with ductile damage occur, severe mesh distorsion takes place after a finite number of incremental steps. Hence an automatic mesh generation with remeshing capabilities is essential to carry out the finite element analysis. Besides, when damage is taken into account a kill element procedure is needed to eliminate the fully damaged elements in order to simulate the growth of macroscopic cracks. The necessary steps to remesh a damaged structure in finite element simulation of forming processes including damage occurrence (initiation and growth) are given. An important part of this procedure is constituted by geometrical and physical error estimates. The meshing and remeshing procedures are automatic and are implemented in a computational finite element analysis package (ABAQUS/Explicit solver using the Vumat user subroutine). Some numerical results are presented to show the capability of the proposed procedure to predict the damage initiation and growth during the metal forming processes.
The Effect of Heat Treatment on the Microstructure of Ti-45Al-5Nb-0.3Y Alloy
Authors: Kong Fan Tao , Chen Yu Yong
Published: March 2009

Effects of heat treatment on the microstructure of as-cast and as-forged Ti-45Al-5Nb-0.3Y alloy are discussed. The as-cast Ti-45Al-5Nb-0.3Y alloy exhibits a microstructure consisting of fine equiaxed grains which average size is almost 100μm. Phase transformation of as-cast Ti-45Al-5Nb-0.3Y alloy greatly depends upon cooling rate. During furnace cooling, the alloy transform to fully lamellar microstructure. During air cooling, massive transformation predominates. During oil cooling, extremely fine fully lamellar microstructure is formed. During water cooling, ordering α2 phases are primary. Thermo-mechanical treatments, through combined action of hot canned forging and heat treatment, were performed on a Ti-45Al-5Nb-0.3Y alloy to investigate their effect on the microstructure of the alloy. The as-forged Ti-45Al-5Nb-0.3Y alloy is comprised of a large number of dynamic recrystallization (DRX) γ grains, curved and broken lamellae, and a small amount of remnant lamellae. And three different microstructures, duplex (DP), nearly lamellar (NL) and fine fully lamellar (FFL), have been obtained through heat treatment at different temperatures (1320-1370°C), respectively.
Apatite Formation on Nano-Structured Titanium and Niobium Surface
Authors: Wang Xiao Jian , Xiong Jian Yu , Li Yun Cang , Hodgson Peter  D. , Wen Cui E
Published: March 2009

Current orthopaedic biomaterials research mainly focuses on developing implants that could induce controlled, guided and rapid healing. In the present study, the surface morphologies of titanium (Ti) and niobium (Nb) metals were tailored to form nanoporous, nanoplate and nanofibre-like structures through adjustment of the temperature in the alkali treatment. The in vitro bioactivity of these structures was then evaluated by soaking in simulated body fluid (SBF). It was found that the morphology of the modified surface significantly influenced the apatite inducing ability. The Ti surface with a nanofiber-like structure showed better apatite inducing ability, than the nanoporous or nanoplate surface structures. A thick dense apatite layer formed on the Ti surface with nanofiber-like structure after 1 week soaking in SBF. It is expected that the nanofibre-like surface could achieve good apatite formation in vivo and subsequently enhance osteoblast cell adhesion and bone formation in vivo.
Evaluation of the Electromagnetic Characteristics on Ag/NiCuZn Ferrite Sintered Bodies
Authors: Ju Dong Ying , Bian Pei , Hou Hua , Zhao Yu Hong
Published: March 2009

Recently, the surface mounting devices (SMD) have been rapidly developed for miniaturisation of electronic applications such as cellular phones, cameras, computers, etc. Low temperature sintering NiCuZn and MnCuZn ferrite was employed at most cases due to its co-firability with Ag (below 960OC).The purpose of this study is to fabricate NiCuZn and MnCuZn ferrite sintered body with high-strength and high-frequency magnetic properties. Following is the procedure: firstly, NiCuZn and MnCuZn ferrite powder were synthesized under CO2 atmosphere at 500 OC from the mixed doxalate synthesized by liquid phase deposition method; then a small amount of boric acid [H3BO3] was added to the powder, and the NiCuZn and MnCuZn ferrite powder compact were prepared with Newton press and CIP methods; finally, NiCuZn and MnCuZn ferrite sintered body was fabricated by sintering at 900 OC under CO2 atmosphere. The effect of boric acid additives on growth of particle and sintering temperature were discussed. The high frequency magnetic properties and density as well as bending strength of the NiCuZn and MnCuZn sintered magnet with various adding of H3BO3 as well as at various sintered temperatures were evaluated by using Impedance analyzer, TMA (Thermo Mechanical Analyzer), TEM (Transmission Electronic Microscopy) and 3-point bending test. From the evaluated results, the most suitable producing conditions were determined and NiCuZn ferrite with wider scope of high frequency and high bending strength were obtained.
Arctic species of the subgenus Symplecta sensu stricto (Diptera: Limoniidae)
Authors: Starý Jaroslav , Brodo Fenja
Published: March 2009

Species of the subgenus Symplecta Meigen with Arctic, or at least partly Arctic, distributions are revised. Five species are redescribed: S. (S.) novaezemblae (Alexander), S. (S.) scotica (Edwards), S. (S.) mabelana (Alexander), S. (S.) sheldoni (Alexander), and S. (S.) horrida (Lackschewitz). Two new species are described: S. (S.) edlundaesp. nov. (Northwest Territories and Yukon, Canada) and S. (S.) echinatasp. nov. (eastern Siberia, Russia). Five new synonyms are proposed: Erioptera (S.) sunwapta Alexander and Helobia intermedia Lackschewitz = S. (S.) scotica; Erioptera (S.) platymera Alexander = S. (S.) mabelana; S. (S.) rotundiloba Podenas and Gelhaus = S. (S.) sheldoni; and Erioptera (Psiloconopa) chaetophora Alexander = S. (S.) horrida. Symplecta (Symplecta) scotica and S. (S.) mabelana are restored as full species from subspecies rank. Symplecta (Symplecta) horrida, previously placed in Erioptera (Mesocyphona) Osten Sacken, is transferred to Symplecta s.s. The distinctions between S. (S.) cana (Walker) and S. (S.) hybrida (Meigen) are clarified and the sympatric and syntopic occurrences of these species are documented. A key to the species treated, and illustrations of both male and female terminalia, are provided and the distribution of each species is outlined.
Occurrence and habitat of the endangered white flower moth, Schinia bimatris (Lepidoptera: Noctuidae), in Manitoba
Authors: Westwood A. Richard , Friesen Christopher P.
Published: March 2009

The only known Canadian population of the white flower moth, Schinia bimatris Harvey, a federally listed endangered species, was rediscovered in 2003 in the dune area of Spruce Woods Provincial Park and Canadian Forces Base Shilo in Manitoba. Little is known about the biology or habitat requirements of this moth in North America. The dune area in Manitoba was surveyed for adult and immature stages of the species during July 2007 using light traps and daytime visual searches. A detailed vegetation survey was also completed in areas where moths were active. Whereas individuals caught in light traps were predominantly males, both females and males were observed to be very active during daylight hours. This is the first record of diurnal activity of the white flower moth in Canada. Adults were observed flying above dune crests and also resting on vegetation between open dunes. Although the current population appears robust, given the number of adults observed, a previous population approximation of up to 5000 individuals may be an overestimate because sand-dune habitat is limited. We were unable to locate immature stages or determine which host plant(s) were utilized by larvae.
Dealing with Shallow-Water Flow in the Deepwater Gulf of Mexico
Authors: Ostermeier R.M. , Pelletier J.H. , Winker C.D. , Nicholson J.W. , Rambow F.H. , Cowan K.M.
Published: March 2009

This paper presents our perspective of the shallow-water flow (SWF) problemin the Deepwater Gulf of Mexico (GOM). The nature of the problem, includingareal extent and overpressuring mechanisms, is discussed. Methods for sandprediction and shallow sediment and flow characterization are reviewed. Theseinclude seismic techniques, the use of geotechnical wells, regional trends, various MWD methods, and cements and settable spots. Finally, examples of flowincidents with pertinent drilling issues, including well failures andabandonment, are described.

Total trouble costs due to shallow-water flow for all GOM operators probablyruns into the several hundred million dollars. Though the problem remains aconcern, advances in our knowledge and understanding make it a problem that ismanageable and not the "show stopper" once feared.

Introduction

SWF may occur while drilling shallow over-pressured formations at deepwatersites. It is a high profile problem in the GOM, though it does occur elsewhere(Ref. 1) and will likely be encountered in other deepwater regions (Fig. 1).

Drilling shallow over-pressured sands may cause large and long lastinguncontrolled flows, well damage and foundation failure, formation compaction, damaged casing, and re-entry and control problems. Most spectacularly, eruptions from over-pressured sands may result in seafloor craters, mounds andcracks (Figs. 2 and 3). Eaton2, 3 has described the significant problems causedby SWF in the Ursa area. A recent inspection of 106 wells (Ref. 4) indicatedthat $175 MM has been spent on SWF and prevention and remediation on thosewells. Total industry costs due to SWF likely exceed several $100 MM.

The problem is compounded by the difficulty in seismically imaging thesesands (Refs. 5 and 6). This stems from the relatively low sand/shale contrastin acoustic impedance. The impact of this problem on well site selection andwell design is significant, and makes drilling in SWF areas particularlychallenging.
Next-Generation Cementing Systems to Control Shallow Water Flow
Authors: Faul Ronnie , Reddy B.R. , Griffith James , Fitzgerald Rocky , Waugh Bryan
Published: March 2009

As documented in industry literature, shallow hazards, especially shallowwater flows (SWF's), pose a challenge in deepwater Gulf of Mexicooperations. 1,2 Cement systems that successfully solved SWF's were first used in1992. The first of these special systems was a lightweight nonfoamed system. In1994, special foamed lightweight systems were implemented and were provensuperior both in large-scale laboratory models and in field use. Severalspecial foamed-cement blends have been used to cement over 300 conductorcasings where SWF's were a threat. These formulations consisted of highlyactivated cements that required special blending at the shore base before beingtransported to the offshore rig. Because dry additives were used, the cementslurry could not be redesigned or modified, so any unused blend had to bediscarded. To address these challenges, the industry developed a lightweightfoamed-cement (LFC) slurry system. This system uses only liquid additives inconjunction with the dry Portland cement on board the rig. The LFC systemprovides a low-density slurry with short transition times to help prevent SWF's while maintaining zonal isolation, adequate placement time, and shorterwaiting-on-cement (WOC) time.

Introduction

Well construction in deep water (>1,000 ft) requires special techniquesfor installing conductor casings. Formations where conductor pipe will becemented are unconsolidated and relatively young geologically (Fig. 1, Page 5). Consequently, these shallow formations have the potential for abnormallypressured saltwater sands, also known as SWF zones. Weak formations andpressured sands present very narrow margins between the pore pressure and thefracture gradient, which can cause a loss of cement returns.

The presence of SWF's in the Gulf of Mexico was first observed in 1985.1 Theeconomic impact of lost wells, rig time, and remedial actions has amounted tomillions of dollars. An economic analysis of SWF's, presented by an operator atthe 1999 International Forum, revealed that the industry has spentapproximately $1.6 million per well on this problem. This analysis alsorevealed that about one-third of the money has been spent on prevention andtwo-thirds on remediation. Some experts believe that more money spent onpreventative measures would result in fewer remedial events. Research money hasalso been spent developing new technology that may provide better, moreeconomical solutions.
Mediation rising: states depend on ADR to help clean up the mortgage mess
Authors: Bleemer Russ
Published: March 2009

How states are relying on mediation to help address the mortgage foreclosure crisis.
Exploring the interactions between signal sequences and E. coli SRP by two distinct and complementary crosslinking methods
Authors: Clérico Eugenia M. , Szymańska Aneta , Gierasch Lila M.
Published: March 2009

Photoaffinity crosslinking comprises a group of invaluable techniques used to investigate in detail a binding interaction between two polypeptides. As the diverse photo crosslinking techniques available display inherent differences, the method of choice will provide specific information about a particular system under study. We used two complementary crosslinking approaches: photo‐induced crosslinking of unmodified proteins (PICUP) and benzophenone‐mediated (BPM) crosslinking to extensively examine the interaction between the signal recognition particle (SRP) and signal sequences. Signal peptide binding by SRP presents a central puzzle in the protein targeting process because signal sequences must be recognized with fidelity but lack strict primary structural homology. The concurrent use of PICUP and BPM crosslinking to link signal peptides to E. coli SRP allowed us to explore the crosslinking pattern resulting from using different crosslinking chemistries, varying the position of the photoprobe in the hydrophobic core of the signal sequence, and shifting the crosslinking reactive group away from the signal peptide backbone. By PICUP, signal peptides crosslinked exclusively to the NG domain of the SRP protein Ffh, regardless of the position of the reactive residue. Benzophenone‐modified amino acids preferentially crosslinked the signal peptide to the C‐terminal (M) domain of Ffh. We conclude that signal peptide binding is largely mediated by the M domain. Importantly, our data also indicate intimate, at least transient, contacts between the hydrophobic core of the signal peptide and the NG domain. These results reopen the possibility of a direct involvement of the NG domain in signal sequence recognition. © 2009 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 92: 201–211, 2009.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Toward an antitumor form of bovine pancreatic ribonuclease: The crystal structure of three noncovalent dimeric mutants
Authors: Merlino Antonello , Krauss Irene Russo , Perillo Margherita , Mattia Carlo Andrea , Ercole Carmine , Picone Delia , Vergara Alessandro , Sica Filomena
Published: March 2009

The cytotoxic action of bovine seminal ribonuclease (BS‐RNase) depends on its noncovalent swapped dimeric form (NCD‐BS), which presents a compact structure that allows the molecule to escape ribonuclease inhibitor (RI). A key role in the acquisition of this structure has been attributed to the concomitant presence of a proline in position 19 and a leucine in position 28. The introduction of Leu28, Cys31, and Cys32 and, in addition, of Pro19 in the sequence of bovine pancreatic ribonuclease (RNase A) has produced two dimeric variants LCC and PLCC, which do exhibit a cytotoxic activity, though at a much lower level than BS‐RNase. The crystal structure analysis of the noncovalent swapped form (NCD) of LCC and PLCC, complexed with the substrate analogue 2 ′‐deoxycytidylyl(3 ′,5 ′)‐2 ′‐deoxyguanosine, has revealed that, differently from NCD‐BS, the dimers adopt an opened quaternary structure, with the two Leu residues fully exposed to the solvent, that does not hinder the binding of RI. Similar results have been obtained for a third mutant of the pancreatic enzyme, engineered with the hinge peptide sequence of the seminal enzyme (residues 16–22) and the two cysteines in position 31 and 32, but lacking the hydrophobic Leu residue in position 28. The comparison of these three structures with those previously reported for other ribonuclease swapped dimers strongly suggests that, in addition to Pro19 and Leu28, the presence of a glycine at the N‐terminal end of the hinge peptide is also important to push the swapped form of RNase A dimer into the compact quaternary organization observed for NCD‐BS. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 1029–1037, 2009.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Anatomy of the posterior inferior cerebellar artery
Authors: Brinjikji Waleed , Cloft Harry , Kallmes David F.
Published: March 2009

Lateral C1‐C2 puncture is associated with a number of complications including damage of aberrant posterior inferior cerebellar arteries (PICA). We propose to determine the frequency of cases in which the PICA originates or descends below C1, thus posing a risk to the patient undergoing lateral C1‐C2 puncture. Two hundred and eleven consecutive patients who received bilateral or unilateral vertebral angiography for evaluation of cerebrovascular lesions were included in this study. In total, 346 PICAs were studied. Lateral vertebral angiograms were analyzed for the location of the origin of the PICA and the inferior‐most portion of the PICA relative to three anatomical regions. Region 1 was defined as the region above the foramen magnum. Region 2 was defined as the region below the foramen magnum but above the inferior border of the posterior arch of C1. Region 3 was defined as the region below the inferior border of the posterior arch of C1. In 2 of 346 angiograms (0.6%) and 2 of 211 patients (0.9%), the caudal loop of the PICA descended to Region 3. The PICA did not originate in Region 3 in any cases. In ∼1% of patients in our study, the caudal loop of the PICA descended into a region that may have placed it at risk for damage during C1‐C2 puncture. Our study suggests that it may be important for radiologists to assess the arterial anatomy of the C1‐C2 region before performing C1‐C2 puncture. Clin. Anat. 22:319–323, 2009. © 2009 Wiley‐Liss, Inc.
Characterization of pure and doped potassium hydrogen tartrate single crystals grown in silica gel
Authors: Quasim I. , Firdous A. , Sahni N. , Khosa S. K. , Kotru P. N.
Published: March 2009

Growth of pure‐, sodium‐ and lithium‐ doped potassium hydrogen tartrate single crystals by gel technique is reported. Growth conditions conducive for the growth of single crystals are worked out. The crystals are characterized by using powder XRD, SEM, FTIR, AES, EDAX, CH analysis and thermoanalytical techniques. The stoichiometric composition for the grown crystals are established as KHC4H4O6.H2O, (K)0.98(Na)0.02.H2O and (K)0.94(Li)0.06HC4H4O6.H2O. Doping of sodium and lithium in the pure potassium hydrogen tartrate single crystals is found to influence the size, perfection, morphology, crystal structure and the thermal stability of crystals. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of light wavelength and intensity on the production of ethanol bySaccharomyces cerevisiaein batch cultures
Authors: Shu Chin‐Hang , Huang Chun‐Kai , Tsai Chieh‐Chung
Published: March 2009

BACKGROUND:Photoreceptors have been identified inSaccharomyces cerevisae, however, the influence of light on the performance of ethanol fermentation ofS. cerevisiaeis not yet clear. The aims of this study are to elucidate the influence of light wavelength and intensity on the growth and ethanol production ofS. cerevisiaeand to describe a novel two‐stage LED light process to optimize ethanol fermentation.

RESULTS:Experimental results indicated that maximum biomass concentration Xmaxof the batch under red LED light increased monotonically with light intensity, and the optimal specific product yield Yp/xwas 13.2 g g−1at 600 lux. Maximum ethanol concentration Pmaxof the batch under blue LED light increased monotonically with light intensity, and the optimal Yp/xwas 18.4 g g−1at 900 lux. A novel two‐stage LED light process achieved maximum Pmax, of 98.7 g dm−3resulting in 36% improvement compared with that of the batch in the dark.

CONCLUSION:The light wavelength and its intensity significantly affected cell growth and ethanol formation ofS. cerevisiae. Red LED light (630 nm) stimulated cell growth but slightly inhibited ethanol formation. In contrast, blue LED light (470 nm) significantly inhibited cell growth but stimulated ethanol formation. A novel two‐stage LED light process has been successfully demonstrated to optimize ethanol fermentation ofS. cerevisiae. Copyright © 2009 Society of Chemical Industry