bluuebunny/crossref_metadata_2025 huggingface dataset:
Enterprise Data Warehouse Governance Best Practices
Authors: Rahman Nayem
Published: March 2016

Maintaining a stable data warehouse becomes quite a challenge if discipline is not applied to code development, code changes, code performance, system resource usage and configuration of integration specification. As the size of the data warehouse increases the value it brings to an organization tends to increase. However these benefits come at a cost of maintaining the applications and running the data warehouse efficiently on a twenty four hours a day and seven days a week basis. Governance is all about bringing discipline and control in the form of guidelines for application developers and IT integration engineers to follow, with a goal that the behavior of a data warehouse application becomes predictable and manageable. In this article the authors have defined and explained a set of data warehouse governance best practices based on their real-world experience and insights drawn from industry and academic papers. Data warehouse governance can also support the development life cycle, maintenance, data architecture, data quality assurance, the Sarbanes-Oxley (SOX) Act requirements and enforce business requirements.
Apps, Apps, and More Apps
Authors: Haught Matthew J. , Wei Ran , Karlis Jack V.
Published: March 2016

This paper explores the reasons millions of people use stand-alone, task-oriented software programs designed for use on mobile devices, commonly known as “apps.” This study uses a survey with a probability sample of 576 app users. Consistent with the uses and gratifications approach, respondents were asked about their attitudes, interests, and opinions regarding apps. Theses measures were reduced to five factors. Then, regression analyses considered the factors as well as app use statistics and demographics to predict app use. The motivations of entertainment, convenience, and instrumentality are consistent with previously studied gratifications of the Internet and the mobile phone. However, the constant availability gratification for apps is unique because they provide quick access to information anytime and anywhere. Regression analysis showed these motivations predicted patterns of app use.
Schematic Classification Model of Green Computing Approaches
Authors: Kesswani Nishtha , Jain Shelendra Kumar
Published: March 2016

Every electronic device has an impact on the environment, and computing devices are not an exception. Green computing is a highly motivated smart computing which tries to save energy and environment by minimizing harmful impacts of computing resource's production and their uses. As the 21st Century is known for Information Technology Revolution, major negative impact of computing resources on environment are day by days increasing contribution to carbon dioxide emission, hazardous substances, e-Waste and high consumption of energy. Nowadays Global Warming is a big issue which is responsible for climate changes. And according to many available facts computing resources are highly affecting it directly and indirectly. So the world's moral duties motivate it to save earth and environment from these harmful impacts, whose outcome is Green Computing. This paper focus on classification of various existing approaches which are used for Green Computing. This classification enhances researcher's concentration on particular classified category for their future contribution so that Green Computing's main aims can be fulfilled.
Model Employee Appraisal System with Artificial Intelligence Capabilities
Authors: Shanmugam Shashidharan , Garg Lalit
Published: March 2016

An employee appraisal system is one of the most critical components of every organization and its effective management leads to higher productivity among the employees. In practice, there are many possible errors or biases in the performance appraisal process. These errors affect the objectivity of the appraisal to a large extent. The most common errors in appraisal include the Halo Effect and Horn Effect, leniency Error (Loose rater), the Error of Strictness (Tight rater), the Central Tendency Error, the Recency Effect, the Contrast Error and the Similarity (similar-to-me) Effect. The aim of this research project is to develop an intelligent IT system to address the issues of existing employee appraisal system. The system would be seamless and reduce human intervention to minimal. The system can be realized as a dashboard. Outcome of this research can be applied in today's businesses. The design of the system mentioned here is a process to ensure that the rater bias is limited. This type of system would be more beneficial for larger organizations with thousands of employees. A limitation could be that this type of application can be overhead for small companies.
Effect of Information Service Competence and Contextual Factors on the Effectiveness of Strategic Information Systems Planning in Hospitals
Authors: Hung Shin-Yuan , Huang Wei-Min , Yen David C. , Chang She-I , Lu Chien-Cheng
Published: March 2016

Many hospitals in Taiwan have started to encounter new and fierce competition as a result of the enactment of the National Health Insurance Policy in 1995. Hospitals should strive to use information technology (IT) strategically to improve their competitive advantage and meet the dynamic challenges in this competitive environment. This study adopts the Technology-Organization-Environment framework to understand the effects of contextual factors (e.g., environmental uncertainty and information intensity) and information service competence on the effectiveness of strategic information systems planning (SISP) to improve hospital management efficiency. A field survey was conducted using questionnaires distributed to accredited hospitals that serve patients from different regions/districts and with academic teaching qualifications/capabilities. These hospitals represent approximately a quarter of all hospitals in Taiwan. The findings show that the environmental unpredictability and business competence of IS executives are negatively related to the two SISP constructs: IT participation in the hospital planning and alignment of the IT plan with the comprehensive hospital plan. In addition, the findings demonstrate that information intensity has a significantly positive relation to both aforementioned SISP constructs. Finally, both constructs justify the significant positive correlations with the use of IT in increasing competitive advantages and improving the satisfaction of customers and end users. This research intends to guide the healthcare industry in raising competitive advantages to improve the operational efficiency of hospital management in today's highly digitalized environment.
Separating the Wheat from the Chaff
Authors: Kakar Adarsh Kumar
Published: March 2016

When making a decision to add features to an existing software product in response to feature requests posted in user forums, it is important to pursue only those changes that deliver value to both the user and the producer. But selecting critical user requirements expressed as features requests is a challenging task. While excluding a high value requirement may mean losing customers to a competing product, including a requirement that is unneeded increases time to market and introduces unnecessary costs and complexity in the product. Keeping these issues in focus, promising methods of feature selection were first identified from a review of requirements engineering, product development and quality literatures. An empirical study was then conducted to investigate the efficacy of methods in separating the vital few user feature requests from the trivial many posted in user forums without adversely impacting user satisfaction. The result of the empirical study demonstrates that the Kano survey method has potential in separating the wheat from the chaff. The reasons for this finding is empirically investigated and discussed.
Effect of Chemical Plating with Ni Content on Thermoelectric and Mechanical Properties of P-Type Bi0.5Sb0.15Te3 Bulk Alloys
Authors: Dai Xue Ting , Yu Yuan , Zu Fang Qiu , Huang Zhong Yue
Published: March 2016

In this work, Bi0.5Sb1.5Te3 powders were coated with various nickel (Ni) contents by chemical plating, and then consolidated into bulk by hot pressing. The results show that Ni particles uniformly coat on the surface of powders and then transform into NiTe2 during the sintering process, after that NiTe2 mainly concentrated at the grain boundaries of bulk. With Ni content increasing, the resistivity of bulk samples and Seebeck coefficient decreased rapidly while thermal conductivity increased. The maximum value of ZT for Bi0.5Sb1.5Te3/Ni sample with 1wt.% Ni is 0.55. Moreover, due to the excellent ductility of Ni that can act as lubricant and binder during the hot pressing process, making the mechanical properties (hardness) of bulks elevated with Ni content increasing. This work suggests that chemical plating technology can improve the mechanical properties and impact the thermoelectric properties of thermoelectric materials. With further tuning the type and content of coating elements, the thermoelectric performance can be improved prospectively.
Charge Behavior of Low-Dimensional V2O5/Graphene Nanoribbons Oxides Nanocomposites under Irradiation of Visible Light and its Application
Authors: Zhang Bo , Zheng Jing , Ma Lu Wei , Guo Bin , He Xiao Chun , Gao Ming Jun , Bian Lin , Ma Xing Fa , Li Guang
Published: March 2016

Due to its outstanding photo-catalysis properties, low-dimensional V2O5 has many important applications in lithium ion batteries, supercapacitors, electrochromic devices, photocatalysts, sensors, et al. As good photocatalysts for organic pollutants, some key issues of photocatalysts are charge generation, separation, transfer of nanocomposites under irradiation of visible light. To improve their important properties and pave the effective conductive channels for charge transfer and separation, low-dimensional V2O5/graphene nanoribbons nanocomposites were prepared. The emphasis is put on adsorption response to VOC of nanocomposite based on the QCM (quartz crystal microbalance) device. In order to investigate the mechanism of charge-generated by visible light, the photoconductivity response to visible light and 808 nm laser with low-power were studied based on interdigital electrodes of Au on flexible PET (polyethylene terephthalate) film substrate. Some good results were obtained. This illustrates that this nanocomposite can easily produce the charge-generate with visible light and 808 nm laser with low-power, avoiding the recombination of charge-generate by light. It would be good applications in remove the organic pollutants with photocatalysis effects.
Impact of pH Value and Temperature on Cement-Based Materials Adsorbing Heavy Metal Ions
Authors: Wang Ya Li , Cui Su Ping , Xu Xi Kui , Lan Ming Zhang
Published: March 2016

The development of the city traffic and its increasing traffic flux are the signs of the development of the society, but causing a serious pollution on the city's ecological environment. Cement hydration reactions are needed to generate Ca (OH)2, C-S-H gel, and AFt, as well as other hydrated products. Meanwhile, heavy metal ions are contained and fixed in a cement paste under physical encapsulation, absorption, isomorphous replacement, and double decomposition. This paper mainly discusses the impact of hydration environment on the adsorption law of materials adsorbing heavy metal ions and the adsorption mechanism under different pH values and temperatures, analyzing specific reasons from the perspective of micro-structure. Through the analysis it can be seen that, in addition to zinc ions, the cement-based materials’ capacity of adsorbing heavy metal ions increases as the pH value and the temperature increase. Micro-structure analysis shows that cement-based materials’ main adsorption methods are different when pH values are different.
Quantification of Pb, Cd and Hg in Waste Rare Earth Phosphors from Abandoned Fluorescent Lamps and Cathode Ray Tubes by ICP-OES
Authors: Yin Xiao Fei , Wu Yu Feng , Zuo Tie Yong
Published: March 2016

A fast and simple method to allow routine analysis of waste phosphors was developed and fully validated. Pb, Hg in waste fluorescent lamps phosphors (WFP) and Pb, Cd in waste CRT phosphors (WCP) were quantified by inductively coupled plasma atomic emission spectrometry (ICP-OES). Analytical conditions, including choice of analytical spectral lines, sample dissolution methods and many other standards, were studied. Wavelengths of 220.353, 228.802, and 184.886 nm were selected as analytical lines for determination of Pb, Cd, and Hg respectively. Studies showed that, Nitric acid could be used for dissolving Cd and Hg, and alkali fusion method for Pb. Detection limits of Pb, Cd, and Hg found were 1.8, 0.3 and 3mg/kg respectively. The proposed method was used in determination of target elements in waste rare earth phosphors, giving values of recovery in the ranges of 96.5%-104%, 98.5%-105% for Pb, Hg in WFP, and 98%-104.5%, 98%-104.5% for Pb, Cd in WCP respectively, and values of RSD less than 8%. Also, influences by dilution factor, coexisting elements and HNO3 Concentration etc. were discussed in the paper.
Surface Modification of Low-Dimensional Heterostructured Functional Materials with Dendrimers and their Properties of Organic-Inorganic Nanocomposites
Authors: Guo Bin , Zhang Bo , Cong Qin , Ma Lu Wei , He Xiao Chun , Gao Ming Jun , Bian Lin , Ma Xing Fa , Li Guang
Published: March 2016

Low-dimensional heterostructured functional materials have been widely applied in new energy materials, catalysts, et al. However, to enhance photo-response in visible light and the biocompatibility improvement are still the great challenges faced. And the dendrimers act good roles in transferring the drug and gene, and has good biocompatibility. Self-assembly on the surface of low-dimensional heterostructured functional materials with dendrimers holding-COOH groups was carried out in this paper. The characterizations of the materials were examined by SEM (scanning electron microscopy), XRD (X-ray diffraction), the Fourier-Transform Infrared (FTIR) spectra, ultraviolet-visible spectroscopy (UV-Vis) and so on. The photoconductivity response to visible light and 808 nm laser with low-power were studied based on interdigital electrodes of Au on flexible PET (polyethylene terephthalate) film substrate. The results indicated that ZnO/CuS modified with dendrimers showed good photo-response to visible light and 808 nm laser, the photo-response properties enhanced greatly by adding some small amount of grapheme oxide. Photocatalytic efficiency was examined by selecting typical organic pollutants, some good results were obtained. The external stimuli driven nanorobots for removal the organic pollutants or toxins in the living body have been developed.
Microstructure and Hydrogen Storage Properties of Ti-V-Fe Alloys
Authors: Fu Gang , Wang Feng , Wang Jiang , Rong Mao Hua , Wang Zhong Min , Rao Guang Hui , Zhou Huai Ying
Published: March 2016

Microstructure, hydrogen storage properties and thermal stabilities of V-Ti-Fe alloys prepared by arc-melting were studied in this work. It was confirmed that V60Ti30Fe10, V70Ti20Fe10 and V80Ti10Fe10 alloys are a body-centered cubic (bcc) single phase, while V75Ti10Fe15 alloy consists of the bcc main phase and C14-typed Laves secondary phase. Experimental results show that the V80Ti10Fe10 alloy reached the largest hydrogen absorption capacities which were about 1.9 wt.% and 1.62 wt.% at 423 K and 473 K, while V75Ti10Fe15 alloy with C14-typed Laves phase showed better hydrogen desorption capacities with 1.31 wt.% at 423 K and 1.35 wt.% at 473 K, respectively. In addition, the DSC measurements indicate that the thermal stability of V75Ti10Fe15 alloy with C14-typed Laves phase decreased, which is very beneficial to the improvement of dehydrogenation rate in the alloy.
Fabrication of Pd-Doped SiO2 Aerogels by Radiation Method
Authors: Zhong Ming Long , Wang Chao Yang , Fu Zhi Bing , Zeng Yong , Fang Qi , Huang Wei , Tang Yong Jian
Published: March 2016

The radiation method was studied to prepare Pd-doped SiO2 aerogels with different contents. The textural properties of the pristine SiO2 aerogels and Pd-doped SiO2 aerogels were systematically characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and N2 adsorption measurements. It can be concluded that there were large amounts of Pd particles presented in the framework of SiO2 aerogels after radiation. In addition, the size of Pd particles increased with the increase of radiation dose. The introduction of Pd nanoparticles produced a reduction of the surface areas, total pore and mesopore volumes.
Analysis of the Environmental Impact of Foam Glass
Authors: Zhang Li Juan , Gong Xian Zheng , Tian Ying Liang , Wang Zhi Hong , Gao Feng , Liu Yu , Li Xiao Qing
Published: March 2016

Foam glass was widely used as a green energy saving material with good performances of light, thermal insulation and sound absorption. Using waste glass as raw material for foam glass production, can not only turn waste into treasure and reduce resource consumption, but also protect the environment. In this article, the foam glass which produced in Jiaxing, China was studied based on the method of life cycle assessment (LCA), and the resources, the energy consumption and the emission of pollutants at the same time were evaluated. The results show that the characterization value of GWP is the largest. The foaming stage is the main contributor which accounts for 79.7%. Similarly, the foaming stage is the major contributor to AP, POCP, EP and HTP .The characterization value of ADP is the smallest. The foaming stage and annealing stage is the main contributor to ADP which account for 43.0%, 49.7% respectively. It has been found that the foaming stage makes the most contribution to the environmental impact. AP, GWP, POCP and EP of the foaming stage are extremely prominent compared to other stages. The authors used the methods of equal weight coefficient and AHP to weight the single indicator. The results show that the environment impact caused by the foaming stage is the largest, then grinding stage and cutting stage follow behind. The environment impact caused by the transportation stage is the smallest.
An Evaluation of Potential Yield of Indium Recycled from Waste Mobile Phone in China
Authors: Wang Heng Guang , Wu Yu Feng , Gu Yi Fan , Mu Xian Zhong
Published: March 2016

In recent years, users replace their mobile phone more and more frequently, therefore, the number of waste mobile phones has been increasing year by year. In 2014, the number was more than 1 billion units. Indium, that has unique optical transparency and electrical conduction properties, is a necessary element in the screen of mobile phone. The potential yield of indium recycled from waste mobile phone is considerable. Recycling indium from waste mobile phones can alleviate the constraints of indium resources while gaining great economic benefit. However, there is no relevant research work to evaluate the potential yield of indium in the waste cell phone. This paper explores the main factors that constraint the efficiency of recycling by predicting potential yield of indium recycled from waste mobile phone, and puts forward the corresponding policy recommendations.
The results are based on the Logistic model and Stock-base model and a survey. The results show that the potential yield of indium recycled from waste mobile phone from 2015 to 2035 will increase from 8.7 tonnes to 10.2 tonnes in China. However, the recovery rate of waste mobile phone is very low, the actual available amount is far lower than the potential yield of indium. The main factors that constrain the efficiency of recycling are: (1) it is difficult to guarantee information security; (2) the existing recycling system is not perfect; (3) the technology of recycling indium needs to be improved.
Materials Flows Analysis on the Beneficiation and Roasting Processes of a Typical Rare Earth Mineral
Authors: Qiu Chuan , Gong Xian Zheng , Chen Wen Juan , Wang Zhi Hong , Gao Feng , Li Xiao Qing
Published: March 2016

The aim of this paper is to explore material flow analysis, study the resource consumption and environmental impact of the production preparation process of typical rare earth materials. The results showed that in the beneficiation processes, producing one ton of rare earth concentrates (Rare Earth Oxide, REO50%) will also produces 27 tons of iron ore and 21 tons of tailings. The recovery of rare earths is only 16.8%. In roasting processes, roasting one ton (REO50%) of rare earth concentrates will emits 150 ~ 200Kg sulfuric acid mist, 500 ~ 600Kg sulfur dioxide, 30 ~ 40Kg fluoride, 30 ~ 50Kg smoke and1t (containing thorium) radioactive slag, and 1.2 tons of concentrated sulfuric acid should be used. The lower recoveries and large-scale of concentrated sulfuric acid used in roasting processes in rare earth industry are the main reasons lead to high pollution and high emissions.
Updated Resource Depletion Characterization Factors for Life Cycle Assessment-Case Studies on Iron and Steel Production in China
Authors: Zhang Yan Jiao , Gao Feng , Wang Zhi Hong
Published: March 2016

In this study, the CML model for resource depletion was updated based on the current status of the mineral resources and the characteristics of relevant statistics in China; and the characterization factors of resource depletion were determined for the majority of natural minerals which are most used in materials industry. Besides, case studies on iron and steel production (BF-BOF and EAF process) were carried out to demonstrate the valid of the modified and localized resource depletion model. The results show that in terms of category, the development of Chinese steel industry is mainly based on the depletion of the natural iron ore and fluorite. The results also show that for BF-BOF process, abiotic resource depletion potential (ADP) in 2012 is 5.26 times of that in 2004; and for the EAF process, ADP in 2012 is 23.6 times of that in 2004. Therefore, the information of ADP needs to be updated at intervals of time.
Environmental Impact Analysis of Typical Exterior Windows for Residential Construction
Authors: Fan Miao Miao , Wang Shu Ping , Wang Zhi Hong , Liu Yu
Published: March 2016

The energy consumption due to heat loss from exterior windows plays an important part in that of the whole building. Therefore, the environmental impact of exterior windows couldn’t be neglected. In this study, the energy consumption and environmental impact were quantified and analyzed based on life cycle assessment methodology. The results showed that both energy consumption and environmental impact of aluminum alloy windows and wood-plastic (WPC) windows mainly occurred at the production stage of aluminum alloy profile and flat glass respectively. At the stage of aluminum alloy profile production, the energy consumption and environment impact were 73.06% and 86% of whole life cycle, and for WPC windows they were 32.95% and 48% at the stage of flat glass production. In addition, the energy consumption and comprehensive environmental impact of aluminum alloy windows during the whole life cycle were 1.26 and 4.59 times more than that of WPC windows.
Life Cycle Assessment of Typical Electric Vehicle IGBT Module
Authors: Li Jun , Wang Cheng , Zhang Bo
Published: March 2016

Based on Life cycle assessment (LCA) methodology, the carbon dioxide (CO2) emission of producing a typical electric vehicle (EV) IGBT module by the GaBi software has been analyzed. Carbon dioxide emission of each step, including raw material production, frontend, backend and transportation, of the whole life cycle was identified and evaluated. The results show that the CO2 emission of the frontend accounts for 51% of the total emission, and that of the backend accounts for 32.8%.
Life Cycle Assessment of Electric Vehicle Power Battery
Authors: Lu Qiang , Wu Peng Fei , Shen Wan Xia , Wang Xue Chao , Zhang Bo , Wang Cheng
Published: March 2016

Based on Life cycle assessment (LCA) methodology, this paper analyzes the total energy consumption and greenhouse gas (GHGs), NOx, SOx and PM emissions during material production and battery production processes of nickel-metal hydride battery (NiMH), lithium iron phosphate battery (LFP), lithium cobalt dioxide battery (LCO) and lithium nickel manganese cobalt oxide (NMC) battery, assuming that the batteries have same energy capacity. The results showed that environmental performance of LFP battery was better than the other three, and that of NiMH battery was the worst. The experimental results also showed the total energy consumption of LFP battery was 2.8 times of NiMH battery and GHGs emission was 3.2 times during material production, and the total energy consumption was 7.6 times of NIMH battery and GHGs emission was 6.6 times during battery production
Study on a Thermoresponsive Shape Memory Polymer Used in Down-Hole Packer
Authors: Fu Tao , Shi Bai Ru , Tong Zheng , Shen Ze Jun , Wei Song Bo , Chen Lin
Published: March 2016

Shape memory polymer (SMP) is being studied and anticipated to be used in a novel down-hole packer. SMP is capable of recovering a predetermined shape following environmental changes, allowing the packer to be altered to a smaller size during run in and to retain its original configuration after activated by the heat in the wellbore. This paper describes the work involved in studying the shape recovery performance of a polyethylene based thermoresponsive SMP under different conditions. The influence of temperature, pressure and degree of deformation on the SMP’s shape recovery performance has been characterized.
Research and Application of Rare Earth Tungsten Electrode Materials
Authors: Zhang Fang Fang , Yang Jian Can , Huang Lin
Published: March 2016

Tungsten is the dominant resources in China, and its reserves and consumption ranks the first place in the world. The tungsten electrode material, as an important manufacture of tungsten product, widely used in metal inert-gas welding, plasma welding, cutting, plasma spraying, is a kind of important industrial material [1]. The radioactive thorium tungsten electrode material is now gradually substituted by rare earth tungsten electrode material since it is excellent in thermal electron emission property. Through many years' study, we have mastered the key technology for the tungsten electrode material. After the extension and application of the key preparation technology, the authors group has developed the rare earth tungsten electrode materials and rare earth tungsten products, and the adjustment of industrial structure and upgrading of the product been realized.
Preparation of Large-Area Porous Silicon through Cu-Assisted Chemical Etching
Authors: Cao Ming , Li Shao Yuan , Deng Jian Xin , Yang Xing Wei , Li Yu Ping , Ma Wen Hui , Zhou Yang
Published: March 2016

Porous silicon (PS) was prepared with catalyst of Cu nanoparticles in HF/H2O2 solutions. The effects of the key fabrication parameters (amount of copper, etching temperature and concentration of H2O2) on the nanostructure of PS were systematically investigated and discussed. The experimental results indicated that the porosity of PS increased with the amount of copper, the reaction temperature and the concentration of H2O2, respectively. Copper can be used as catalyst to assist in etching silicon and the evolution process of copper nanoparticles was explored showing that the mass of copper experienced a drastic reduction in the first 60 seconds. A mechanism is proposed to explain the formation of PS by Cu-assisted chemical etching.
Radio-Frequency Electromagnetic Properties of FeSiCr–Epoxy Composites Prepared by Cryomilling
Authors: Xie Pei Tao , Fan Run Hua , Hou Qing , Dang Feng
Published: March 2016

FeSiCr-epoxy composites consisting of different FeSiCr contents were prepared through the pressure molding after mixing by cryomilling at liquid nitrogen temperature. The electromagnetic properties including ac conductivity, permittivity, and permeability were investigated in detail. The results show that the frequency dispersions of ac conductivity followed the power law, indicating the hoping conduction behavior. The real permittivity of composites increased with the increase of FeSiCr contents, and the enhancement of permittivity may be attributed to the increase of the interface area between FeSiCr and epoxy, while Debye-like dielectric relaxations were observed, and the fitting analysis of Cole-Cole curve indicates a nonideal Debye relaxation. The frequency dispersions of permeability were also relaxation linetype, which is attributed to the domain wall displacement.
Influence of Sintering Temperatures on Microstructures and the Thermal Conductivity of CuAlO2 Ceramics
Authors: Song Zi Jun , Wang Lian Jun , Jiang Wan , Luo Wei
Published: March 2016

Oxide ceramic is a kind of environmental friendly materials, which has attracted more and more interests for its bunch of advantages such as sound chemical, thermal stability, simple synthetic process, cheap price, harmless and safety. Therefore, Oxide ceramic will be a promising material in the future. In this work, polycrystalline samples of CuAlO2 were prepared by a solid state reaction method. The mixture of pure CuO and Al2O3 powders was firstly pressed under the pressure of 60 MPa, and then 200 MPa to prepare pellets of 5 mm thick and 10 mm in diameter. The green compacts were sintered at five different temperatures (1273 K, 1323 K, 1373 K, 1423 K, 1473 K) for various holding times (5 h, 10 h and 15 h) in the air and then the furnace cooled. The crystalline and microstructures of the sintered CuAlO2 bodies were detected by XRD and SEM. The properties of density, thermal conductivity were also investigated in detail. The experimental results show that CuAlO2 bodies were rhombohedral, belonging to R3m space group. It is found that the density and the thermal conductivity of CuAlO2 ceramics were significantly dependent on the sintering temperatures. The density and thermal conductivity increased with increasing the sintering temperatures. The thermal conductivity of samples sintered at 1273 and 1473 K with the same holding time (10 h) were 9.70 and 35.53 W/mk at the room temperature, 3.41 and 8.29 W/mk at 1100 K, respectively.
Preparation and Properties of SiC Porous Ceramics Made by Oxidation-Bonding Technique
Authors: Li Hong Fang , Xia Yi , Zhao Hong Ling
Published: March 2016

SiC porous ceramics were prepared by oxidation-bonding technique using SiC powder as main material and carbon black as pore former. The phase composition, surface morphologies, bulk densities, porosities, mass and linear changes of the samples were also investigated. The physical-chemical properties have been analyzed. The results indicate that the oxidation reaction of SiC ceramics was accelerated with the increase of temperatures. It displays undamaged surface after 1400°C treatment, as well as fused surface after 1450°C treatment. The latter is attributed to violent oxidation reaction of SiC. As C contents increase, the porosities of the samples increase and the infiltration of O2 into interior of SiC ceramics was facilitated. The internal network microstructure is controlled by O2 infiltration and SiO2 coating.
Preparation of SiC Porous Ceramic for Application in Filter Plate Supports
Authors: Bao Qi Fu , Dong Wei Xia , Zhou Jian Er , Hu Xiao Chun
Published: March 2016

In order to improve the efficiency of solid-liquid separation, dewatering and filtration, as well as to reduce the loss of concentrate and production costs, silicon carbide porous ceramic filter plate with high porosity and high bending strength was prepared by using the particles close packing method adding proper amount of adhesives and sintering additives at 1450 oC. The porosity of the fired samples was evaluated by Archimedes law. The morphology and properties of the samples were characterized. Effects of SiC grains gradation, pore formers content, molding pressure and soaking time on the bending strength and porosity of ceramic filter plate was studied. SiC porous ceramic composition was prepared by mixing 90wt% and 10wt% SiC powders with D50 of 200.7 μm and 312.6 μm, respectively, 4% walnut powder as pore former and 5% Kaolin clay as binder. The sample was pressured at 8 MPa and fired at 1450 oC for 30 min, and endowed with 6-8 μm of the average pore diameter, 41% of the porosity and 11 MPa of the bending strength, respectively, which is especially not easy to plug hole. The obtained results can be applied in ceramic filter core parts for heavy metal concentration.
Effect of B2O3 and P2O5 Addition on the Phase Separation and Crystallization of Li2O-MgO-Al2O3-SiO2  Glass-Ceramics
Authors: Bao Zhen Hong , Miao Li Feng , Jiang Wei Hui , Liu Jian Min , Liang Jian , Chen Ting
Published: March 2016

B2O3- or P2O5-doped Li2O-MgO-Al2O3-SiO2 (LMAS) glass-ceramics were prepared by solid state method using Li2CO3, MgO, Al2O3 and SiO2 as the raw materials, B2O3 or P2O5 as the additives. The effects of adding B2O3 and P2O5 on the phase separation, crystallization and thermal expansion coefficient were investigated by means of X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electron microscopy (SEM) and thermal dilatometer, respectively. The results showed that B2O3 or P2O5 addition could promoted phase separation of glass and increased the size of spherical phase separation droplet. With the addition of B2O3 or P2O5, the crystallization temperatures (Tc) of LMAS system decreased from 764 oC to 726 oC and 764 oC to 750 oC, respectively. However, the crystalline phase compositions did not changed, and β-quartz solid solution (s.s) (Li2Al2Si3O10) was still the main crystalline phase, and lithium silicate (Li2SiO3) and forsterite (Mg2SiO4) were the minor phases. The thermal expansion coefficient (α) of B2O3-doped and P2O5-doped LMAS glass-ceramics in the temperature range 20-600 oC were 5.215×10-6/ oC and 5.008×10-6/ oC, respectively, which were higher than that of LMAS glass-ceramics (α=3.790×10-6/ oC).
Fabrication of Porous Al2O3 Ceramics by Freeze Drying Technique and Annealing Treatment
Authors: Qiu Sha , Tang Yu Fei , Zhao Kang
Published: March 2016

Porous Al2O3 ceramics were fabricated by directional freezing and low pressure drying with sucrose solution as the cryogenic medium. The pore structure of the porous ceramics was changed by annealing in the environment of higher than the glass transition temperature of sucrose solution after directional freezing because of changing the size and distribution of crystalline solid. The effects of the annealing time on the pore structure, open porosity and mechanical property of porous ceramics were investigated. The results showed that the pore size of porous ceramics increased substantially with the increase of annealing time. The open porosity of porous ceramics changed slightly with the increase of annealing time, while the compressive strength of porous ceramics showed a trend of decrease. The pore size range of porous Al2O3 ceramics fabricated is from 6.0μm to 110.2μm, the range of porosity was 40.35%-64.58%, the compressive strength range of porous Al2O3 ceramics was from 25.9MPa-126.6MPa. The porous Al2O3 ceramics with different pore structure can be obtained by changing the annealing time.
Study on Mullite Whiskers Preparation via Non-Hydrolytic Sol-Gel Process Combined with Molten Salt Method
Authors: Fu Kai Lin , Jiang Wei Hui , Liu Jian Min , Feng Guo , Pan Mu
Published: March 2016

Mullite whiskers were prepared via non-hydrolytic sol-gel process combined with molybdate molten salt using tetraethoxysilane and anhydrous aluminum chloride as precussor, anhydrous ether as oxygen donor, molybdate as molten salt. The effects of heat treatment temperature, molten salt amount, holding time on synthesis and morphology of mullite whiskers were investigated by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The results show that the mullite whiskers appeared at the lowest temperature of 800°C, and optimized mullite whiskers could be prepared at 900°C for 8 h with the mass ratio of xerogel and molybdate as 1:2, the diameter of the whiskers was in the range of 0.15-0.22 μm with the aspect ratio of more than 40.
2D Meso-Scale Finite Element Modeling and Simulation of Polymer-Mineral Composite Material
Authors: Sheng Pei Yao , Wang Shi Zhao , Ji Zhong
Published: March 2016

Polymer-mineral composite material is prepared by using modified epoxy resin as binder and mineral particles as aggregates. Its excellent damping characteristic and low thermal expansion make it ideal in manufacturing machine tool beds. However, the properties of this material depend on its formula and structure, so it is very important to develop an efficient method to numerically model the materials and then to optimize their properties. In this paper, 2D meso-scale finite element modeling is presented for numerical analysis of the mechanical properties of polymer-mineral composite material. The material was treated as a 2-phase composite composed of aggregates and binder which was epoxy resin mixed with fillers. Based on grading curve, the weights of aggregates were converted into the corresponding area, the aggregate particles were randomly generated and assembled with binder to produce the model. And then 2D numerical simulations were conducted under different gradations. The results show that: (1) the 2D FE model is very close to the real polymer-mineral composite material in the aspect of density and aggregate shapes and sizes, which validate the fidelity of the generated finite element model and numerical analysis method; (2) by comparing the materials’ properties under four different gradations, it can be found that the materials with SAC gradation have the best mechanical property.
Study on TaC Reinforced Iron Matrix Surface Gradient Composites Produced In Situ
Authors: Zhao Na Na , Xu Yun Hua , Song Ke , Shen Liu Liu , Ovcharenko V.E.
Published: March 2016

Tantalum carbide (TaC) gradient composites were fabricated via in-situ fabrication method from the tantalum plate and gray cast iron. The morphology, phase constituents, micro-hardness, and relative abrasion resistance of the composites were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), micro-hardness tester and abrasive wear testing machine. The surface layer, which was ~160μm thick, was dense ceramic layer composed by ~90% submicron TaC particulates. The highest micro-hardness value of the dense ceramic layer was 13.84 GPa. In the sub-layer, the gradient distribution of TaC particulates reflected in the volume fraction decreased from 90% to 0%. While the micro-hardness value decreased from 10.81 GPa to 4.10 GPa. The metallurgical combination of the interface between the composites and matrix was perfect. The wear resistance of TaC reinforced iron matrix surface gradient composites increased significantly.
Effects of Pore-Forming Agent on Characterization of NiO/YSZ Porous Anode for SOFC
Authors: Ding Chag Ku , Zhang Jing De , Liu Ya Lei , Gou Jin Yan , Luan Jun Peng
Published: March 2016

A comparative study has been carried out on the effects of pore-forming agents on the microstructural characteristics and properties including porosity, microstructures, linear sintering shrinkage and mechanical strength of NiO/yttria stabilized zirconia (YSZ). Different pore-forming agents (soluble starch, graphite and activated carbon) were incorporated into NiO/YSZ at various mass mixing ratios (5%, 10% and 15%). The experimental results show that under the condition of same content, sintered samples using activated carbon as pore-forming agent had a higher porosity than that with identical content of the other two kinds of pore-forming agents. Sintered samples with 10.0 wt% activated carbon had a porosity of 35%. Section morphologies show that pores distributed uniformly and connected very well in the anode with activated carbon as pore-forming agent. The mechanical strength of these sintered samples with carbon as pore-forming agent was also higher. With the activated carbon particle size decreasing (from 100 mesh to 320 mesh), the open porosity of porous NiO/YSZ was reduced (from 31.7% to 30.9%). It may be concluded that The activated carbon is the better choice as pore-forming agent for NiO/YSZ anode.
Improve the P-Type Conductivity of SnO Films by Na Ion Implantation
Authors: Yang Tie Ying , Zhao Jun , Li Xiao Long , Gao Xing Yu , Xue Chao Fan , Wu Yan Qing , Tai Ren Zhong
Published: March 2016

P-type transparent conducting SnO thin films were directly fabricated using RF magnetron sputtering. The electronic properties of the SnO thin films were enhanced by Na ion implantation and annealing at 200°C. The growth and implantation conditions were systemically investigated. The electronic properties, optical properties, microstructure and surface morphologies of the films were characterized. It was observed that the structure of the Na-doped SnO films was crucial to improving their p-type conductivity.
Preparation of N-Type Cuprous Oxide Films via Electrodeposition Method and their Photoelectrochemical Activities
Authors: Wen Yuan , Zou Yuan Zhuang , Wen Si Yi , Hu Fei
Published: March 2016

The n-type Cu2O films were deposited on ITO substrate by three-electrode electrochemical deposition method in a CuSO4-lactic acid electrolyte. The effects of electrolyte pH, bath temperature, and annealing treatment on films’ conductivity and their photoelectrochemical activity were investigated by X-ray diffraction (XRD), photocurrent (I-t) and mott-schottky (M-S) plots. The results show that the n-type Cu2O could be electrodeposited at electrolyte pH of 8.5, 9 and 10, and the electrolyte temperature did not change the films’ conductivity. The highest n-type photocurrent density of 0.014 mA /cm2 and carrier concentration of 2.3×1019 cm-3 was obtained when the electrolyte pH was 8.5 and the bath temperature was 60°C. With increasing annealing temperature from 150°C to 400°C, the photocurrent density and carrier concentration of n-type Cu2O thin films correspondingly increased, indicating that heat treatment is helpful to improve the photoelectrochemical activity.
Hall-Petch Relation in a Spheroidized Carbon Steel with Emphasis on the Effect of Intergranular Particles
Authors: Ning Jiang Li , Feng Yun Li , Li Jie
Published: March 2016

The Hall-Petch relation in a spheroidized steel with bimodal cementite particle size distribution has been investigated in this study, with an emphasis on considering the effect of the large particles at ferrite grain boundaries and triple junctions. A medium carbon steel was processed by variable thermomechanical procedures to achieve spheroidized structures with different combinations of microstructrual parameters, but all exhibiting a bimodal particle size distribution, in which large intergranular particles and small intragranular particles coexisted in the ferrite matrix. A quantitative relationship between the Hall-Petch parameter ky and the volume fraction of the intergranular cementite particles is presented, by considering a composite model. The contribution of the large intergranular particles to grain boundary strengthening wa substantiated by the increment of the ky parameter, since the average orientation factor of the composite, is increased. After correction of the ky parameters based on the constants from literatures, the predicted stresses show good agreement with the experimental stresses. A linear fit between the experimental stresses and the reciprocal square root of grain sizes is performed, the slope constant ky derived agrees to within 11 % of the corrected ky parameters based on the constants from literatures.
A Study on Ultra-Hard AlMgB14 Modified by TiB2 and Ni3Al
Authors: Zhou Yu Mei , Zhang Feng Lin , Li Peng Cheng , Bai Kun , Wu Shang Hua
Published: March 2016

AlMgB14 is a very hard and brittle material which need be modified for utilizing as cutting tool materials. In present study, TiB2 and Ni3Al were used to strengthen and toughen AlMgB14 material. The microstructure of the AlMgB14-TiB2-Ni3Al composites was analysized by scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDX) and an X-ray diffractometer (XRD). The hardness and fracture toughness of the AlMgB14-TiB2Ni3Al composites were also examined. The results showed that the major phases in AlMgB14-Ni3Al composites were TiB2, AlMgB14, MgAl2O4 , Ni3Al and NiAl. With the increasing of the amount of Ni3Al, more intergranular fractured features can be found in the fractured surface of the composites, the hardness and fracture toughness of the composites were both decreased comparing to the synthesised AlMgB14. The AlMgB14-TiB2-4wt.% Ni3Al composite has a hardness of 28.1 Gpa and a fracture toughness of 3.14 MPa·m1/2.
High Thermal Conductive Insulation Composite Materials
Authors: Wang Yang , Tao Zhi Qiang , Chen Jian Sheng
Published: March 2016

Compact design and smart device has becoming a popular trend for electric and electronic application. With the increase of power and function, the heat accumulation is a new challenge. High thermal conductive insulation material becomes a hot research area in recent years. The current paper reviews the recent progress of high thermal conductive insulation material; and the influence of the composition, structure regularity of resin, functional filler, manufacture process on the thermal conductivity of composite material is discussed. The open topics and future trend are also summarized.
Tension-Compression Asymmetry in an Extruded Mg Alloy AZ31: Texture and Strain Rate Effects
Authors: Chang Li Li , Chi Li Peng
Published: March 2016

The influence of initial texture and strain rate on the mechanical behavior, especially anisotropy and tension-compression asymmetry (TCA) in AZ31 was investigated. The results indicated that the TCA in AZ31 decreased as the strain rate increased, plastic anisotropy increased as the strain rate increased. After compression, the massive twins were observed in AZ31 samples compressed on the extruding direction, while the fraction of twins in samples compressed perpendicular to the ED was smaller.
Effects of Filtration Purification and Solution Treatment on the Microstructure and Mechanical Property of AZ91D Alloy
Authors: Liu Wang Han Bo , Qi Wen Jun , Huang Zheng Hua
Published: March 2016

As-cast and solution-treated microstructures of AZ91D alloy before and after the purification by MgO ceramic foam filter (CFF) with different thicknesses at the range from 15 mm to 35 mm were investigated by optical microscopy and scanning electron microscopy. Meanwhile, the tensile mechanical property and impact toughness were tested. The results show that the impurities in the alloy melt could be eliminated by the filtration purification effectively. With increasing the thickness of CFF, the tensile mechanical property and impact toughness first increased significantly, and then decreased slightly. The AZ91D alloy purified by the CFF with the thickness of 20 mm and the porosity of 10 ppi exhibited the best comprehensive mechanical property. The tensile strength σb, elongation δ and impact toughness αnK at ambient temperature reached 205 MPa, 8.5% and 16 J/cm2, with the improving amplitude of 13%, 31% and 46% comparing with the corresponding unpurified value, respectively. At the same time, σb and δ at elevated temperature reached 195 MPa and 31.5%, with the improving amplitude of 9% and 174%, respectively. After the alloy was solution treated, the mechanical property was enhanced further, and the improving amplitude was larger for the alloy by the filtration purification. σb reached 260 MPa and 205 MPa at ambient and elevated temperatures, with the improving amplitude of 32% and 5% comparing with the unpurified value, respectively. αnK reached 27 J/cm2, with the improving amplitude of 69%.