bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative Study on Dry Etching of α- and β-SiC Nano-Pillars
Authors: Choi J.H. , Latu-Romain Laurence , Bano Edwige , Henry Anne , Lee Won Jae , Chevolleau Thierry , Baron Thierry
Published: March 2013

A comprehensive study on different polytypes (α-SiC and β-SiC) and crystal orientations ((0001) and (11-20) of 6H-SiC) has been investigated in order to elaborate Silicon carbide (SiC) nanopillar using inductively coupled plasma etching method. The SiC nanopillars with the cross section of rhombus, pentagon, and hexagonal have been obtained on β-SiC (001), misoriented α-SiC (11-20), and α-SiC (0001) on-axis substrates, respectively. It was found that crystal orientations and polytypes play key roles for the morphology of SiC nanopillars, which reflects the so-called Wulff's rule.
First Experimental Functionalization Results of SiC Nanopillars for Biosensing Applications
Authors: Fradetal Louis , Stambouli Valerie , Bano Edwige , Pelissier Bernard , Wierzbowska Katarzyna , Choi Ji Hoon , Latu-Romain Laurence
Published: March 2013

DNA biosensors based on silicon carbide nanowire bioFET (SiC NW bioFET) benefit from both biocompatibility and semiconducting properties of SiC. One of the device realization key points is the functionalization of the SiC NW. This process is composed of two main steps: silanization and DNA grafting. It has been successfully carried out on both SiC single crystals and SiC nanopillars. Evidences of DNA detection are given by X-Ray photoelectron Spectroscopy (XPS) and fluorescence microscopy.
Electrical Characteristics of Large Chip-Size 3.3 kV SiC-JBS Diodes
Authors: Okino Hiroyuki , Kameshiro Norifumi , Konishi Kumiko , Inada Naomi , Mochizuki Kazuhiro , Shima Akio , Yokoyama Natsuki , Yamada Renichi
Published: March 2013

The reduction of reverse leakage currents was attempted to fabricate 4H-SiC diodes with large current capacity for high voltage applications. Firstly diodes with Schottky metal of titanium (Ti) with active areas of 2.6 mm2 were fabricated to investigate the mechanisms of reverse leakage currents. The reverse current of a Ti Schottky barrier diode (SBD) is well explained by the tunneling current through the Schottky barrier. Then, the effects of Schottky barrier height and electric field on the reverse currents were investigated. The high Schottky barrier metal of nickel (Ni) effectively reduced the reverse leakage current to 2 x 10-3 times that of the Ti SBD. The suppression of the electric field at the Schottky junction by applying a junction barrier Schottky (JBS) structure reduced the reverse leakage current to 10-2 times that of the Ni SBD. JBS structure with high Schottky barrier metal of Ni was applied to fabricate large chip-size SiC diodes and we achieved 30 A- and 75 A-diodes with low leakage current and high breakdown voltage of 4 kV.
SXRT Investigations on Electrically Stressed 4H-SiC PiN Diodes for 6.5 kV
Authors: Kallinger Birgit , Berwian Patrick , Friedrich Jochen , Hecht Christian , Peters Dethard , Friedrichs Peter , Thomas Bernd
Published: March 2013

4H-SiC PiN diodes for 6.5 kV were manufactured on both 4° and 8° off-cut substrates and subjected to an electrical stress test on wafer level and subsequent analysis of structural defects present in the active area of the diodes. For 8° off-cut diodes, the electrical characteristics with respect to leakage current and forward voltage drift are worse than the electrical characteristics of 4° off-cut diodes. Furthermore, a large number of stacking faults was found in 8° off-cut diodes, but little evidence for bipolar degradation was found in 4° off-cut diodes. Therefore, bipolar degradation was significantly reduced by avoiding BPDs in the active area of PiN diodes, i.e. by the use of 4° off-cut substrates. Furthermore, a strong correlation was found between the electrical screening test on wafer level and critical defects.
Development of High-Voltage 4H-SiC PiN Diodes on 4° and 8° Off-Axis Substrates
Authors: Okamoto Dai , Tanaka Yasunori , Matsumoto Norio , Mizukami Makoto , Ota Chiharu , Takao Kazuto , Fukuda Kenji , Okumura Hajime
Published: March 2013

13-kV 4H-SiC PiN diodes were fabricated on 4° and 8° off-axis substrates and their electrical properties were examined. Small test PiN diodes with various JTE concentrations were fabricated and the dependence of JTE concentration was examined. The highest breakdown voltages were 14.6 and 14.1 kV at a JTE1 concentration of 1.9 × 1017 cm−3 for both the 4° and 8° off-axis substrates. Based on the results, 4 mm × 4 mm SiC PiN diodes were successfully fabricated and exhibited avalanche breakdown voltages of 14.0 and 13.5 kV for the 4° and 8° off-axis substrates, respectively. Forward voltage degradation was larger for the 8° off-axis substrates.
Defect Generation Mechanisms in PVT-Grown AlN Single Crystal Boules
Authors: Raghothamachar Balaji , Yang Yu , Dalmau Rafael , Moody Baxter , Craft H. Spalding , Schlesser Raoul , Dudley Michael , Sitar Zlatko
Published: March 2013

A systematic study on the density and distribution of extended defects in a typical single crystal AlN boule grown by the physical vapor transport (PVT) method has been carried out in order to gain a detailed understanding of the formation of defects such as dislocations and low angle grain boundaries (LAGBs). Boule surface studies reveal that LAGBs are nucleated during initial stages of growth and propagate to the end of growth. Basal plane dislocations (BPDs) are generated during growth due to thermal gradient stresses. Higher BPD densities are found near the LAGBs at the boule edges due to additional stresses from constrained growth. Threading edge dislocations (TEDs) are typically replicated from the seed, and LAGBs composed of arrays of threading dislocation walls are formed to accommodate the c-axis rotation between different groups of threading screw dislocation (TSD) mediated growth centers.
A 69-mΩ 600-V-Class Hybrid JFET
Authors: Akiyama Satoru , Shimizu Haruka , Yokoyama Natsuki , Tamaki Tomohiro , Koido Sadayuki , Tomizawa Yoshikazu , Takahashi Toyohiko , Kanazawa Takamitsu
Published: March 2013

A hybrid silicon-carbide junction-gate field-effect transistor (HJT: hybrid JFET) is proposed. The HJT consists of a silicon-carbide (SiC) normally-on vertical JFET and a low-voltage normally-off silicon metal-oxide-semiconductor field-effect transistor (Si-MOS: silicon MOSFET). These two devices are connected by bonding wire as a cascode circuit [1] and packaged in a TO-3P split-lead-frame package with the same pin arrangement as conventional silicon power devices, which can thus be easily replaced by the proposed HJT. The vertical JFET has a steep-junction deep-trench structure in its channel region. This structure gives a low on-state resistance of under 60 mΩ and breakdown voltage of over 600 V with the die size of 6.25 mm2. Since the deep-trench structure also lowers the cutoff voltage of the JFET, required minimum breakdown voltage of the Si-MOS is reduced and on-state resistance of the Si-MOS is lowered. The HJT demonstrated on-state resistance of 69 mΩ and breakdown voltage of 783 V. These results indicate that the proposed HJT is a strong candidate for low-resistance high-power switching devices.
Thermal Runaway Robustness of SiC VJFETs
Authors: Ouaida Rémy , Buttay Cyril , Hoang Anhdung , Riva Raphaël , Bergogne Dominique , Morel Hervé , Raynaud Christophe , Morel Florent
Published: March 2013

Silicon Carbide (SiC) Junction-Field Effect Transistors (JFETs) are attractive devices for power electronics. Their high temperature capability should allow them to operate with a reduced cooling system. However, experiments described in this paper conclude to the existence of runaway conditions in which these transistors will reach destructive temperatures.
15 kV IGBTs in 4H-SiC
Authors: Ryu Sei Hyung , Capell Craig , Jonas Charlotte , O'Loughlin Michael J. , Cheng Lin , Lam Khiem , Burk Albert A. , Richmond Jim , Clayton Jack , Hefner Allen , Grider David , Agarwal Anant , Palmour John W.
Published: March 2013

The latest developments in ultra high voltage 4H-SiC IGBTs are presented. A 4H-SiC P-IGBT, with a chip size of 8.4 mm x 8.4 mm and an active area of 0.32 cm2, which is double the active area of the previously reported devices [1], exhibited a blocking voltage of 15 kV, while showing a room temperature differential specific on-resistance of 41 mΩ-cm2 with a gate bias of -20 V. A 4H-SiC N-IGBT with the same area showed a blocking voltage of 17 kV, and demonstrated a room temperature differential specific on-resistance of 25.6 mΩ-cm2 with a gate bias of 20 V. Field-Stop buffer layer design was used to control the charge injection from the backside. A comparison between N- and P- IGBTs, and the effects of different buffer designs, are presented.
Fabrication of a P-Channel SiC-IGBT with High Channel Mobility
Authors: Katakami Shuji , Fujisawa Hiroyuki , Takenaka Kensuke , Ishimori Hitoshi , Takasu Shinji , Okamoto Mitsuo , Arai Manabu , Yonezawa Yoshiyuki , Fukuda Kenji
Published: March 2013

We fabricated and characterized an ultrahigh voltage (>10kV) p-channel silicon carbide insulated gate bipolar transistor (SiC-IGBT) with high channel mobility. Higher field-effect channel mobility of 13.5 cm2/Vs was achieved by the combination of adopting an n-type base layer with a retrograde doping profile and additional wet re-oxidation annealing (wet-ROA) at 1100°C in the gate oxidation process. The on-state characteristics of the p-channel SiC-IGBT at 200°C showed the low differential specific on-resistance of 24 mΩcm2 at VG = -20 V. The forward blocking voltage of the p-channel SiC-IGBT at 25°C was 10.2 kV a the leakage current density of 1.0 μA/cm2.
Area-Optimized JTE for 4.5 kV Non Ion-Implanted 4H-SiC BJT
Authors: Salemi Arash , Elahipanah Hossein , Buono Benedetto , Zetterling Carl Mikael , Östling Mikael
Published: March 2013

Non ion-implantation mesa etched 4H-SiC BJT with three-zone JTE of optimized lengths and doses (descending sequences) has been simulated. This design presents an efficient electric field distribution along the device. The device area has been optimized and considerably reduced. As a result of this comprehensive optimization, a high breakdown voltage and high current gain have been achieved; meanwhile the device area with a constant emitter and base contact area has been reduced by about 30%.
Growth of (0001) AlN Single Crystals Using Carbon-Face SiC as Seeds
Authors: Sumathi Rajappan Radhakrishnan , Paun Matthias
Published: March 2013

Growth of AlN single crystals using carbon-polar surface of SiC substrate by PVT growth method has been attempted. AlN growth on the carbon-face was dominated by spiral growth mode under the applied experimental conditions and further, an abrupt interface was observed between AlN layer and the substrate. Broad XRD rocking curve of the sample, taken from bottom part of the crystal, indicates a high density of misfit dislocations near the interface and further a shift of E2(high) phonon mode in the Raman measurements shows a significant misfit stress. The XRD-RC FWHM values of symmetric 002 and asymmetric 102 reflections (top part of the crystal) are 380 and 300 arcsec respectively, whereas the Raman E2(high) peak FWHM value is about 23 cm-1. Decreasing intensity of silicon and carbon LVM peaks with increasing distance from the interface represents the reduction of their incorporation along the crystal length. EPMA analysis confirms the presence of low silicon concentration of 2 wt% in these crystals grown hetero-epitaxially on SiC.
Optimization of Holding Current in 4H-SiC Thyristors
Authors: Soloviev Stanislav , Elasser Ahmed , Katz Sarah , Arthur Steve , Stum Zach , Yu Liang Chun
Published: March 2013

Two designs (A and B) of 4H-SiC thyristors for pulse power applications were implemented and characterized in this work. Both designs have the same layout and epi-layer stack except for the anode layers: thyristors with design A (baseline) had a thin (~0.5 um) anode while devices with design B (optimized) consisted of a heavily doped cap layer (~0.5 um, ~1019/cc) and ~1.5 um p-type layer with lower doping (~1018/cc). All devices were fabricated in 4” 4H-SiC subSuperscript textstrates (three wafers per each design) and were fully characterized at the wafer level including measurements of forward voltage, blocking voltage, leakage current, and holding current. It was shown that the mean value of the holding current in the thyristors with thin anode was significantly higher (0.7A) than that of the thyristors with thick anode (0.1A), while other parameters had practically the same values. The open circuit voltage decay (OCVD) method was used for measurements of the minority carrier lifetime in order to correlate it with the holding current. Impact of material properties and device design parameters on the holding current is discussed as well.
Micromechanics Based on Silicon Carbide
Authors: Astashenkova Olga N. , Korlyakov Andrej V. , Luchinin Victor V.
Published: March 2013

This paper describes using of silicon carbide for micromechanical systems. Low stressed sensitive membrane signal converters, thin film transducers and piezoresistive sensors were formed based on silicon carbide films. The mechanical properties of silicon carbide films were determined.
A Novel Thermoelectric Generator for the Detection of Electrical Equipment
Authors: Yu Hong Tao , Zhang Zhi Feng , Qiu Qing Quan , Sun Qiang , Zhang Guo Min , Dai Shao Tao
Published: March 2013

Semiconductor thermoelectric generators have a series of advantages, such as compact volume, high-level reliability, and effective power generation in the presence of temperature difference. In many occasions, as a result of high voltage, electrical equipments can't be measured by the way of direct contact. In order to avoid equipment faults caused by low-voltage contact, a thermoelectric generator which uses waste heat of electrical equipments in service was designed. Electrical equipments often operate below 400K, and in this condition Bi2Te3 shows an outstanding performance of power generation. In order to solve the problems of little temperature difference and output power on steady-state, two methods were introduced. On the one hand, the temperature difference can be increased by filling with thermal insulation padding between the p-n junctions and using a heat sink in the cold side, and on the other hand, the output voltage and power will be augmented by increasing the number of p-n junctions. These methods have been proved effectively by simulation and experiment with promising outcomes.
Research on Preparation and Structure of Ca3Co4O9
Authors: Zhang Wei Rong , Wang Zhan Yong , Liu Wen Qing
Published: March 2013

Ca3Co4O9 particles were synthesized using cobalt nitrate, calcium nitrate, and citric acid as the starting precursors by sol-gel method. The absolute ethyl alcohol was selected as the solvent. LFA447 was applied to measure the thermal conductivity from room temperature to 300 as the reference to decide the optimal parameters. And the optimal parameters obtained are as follows: ethyl alcohol 100ml, ethylene glycol 5ml, citric acid 12.11g (the mole ratio of citric acid to metal ions is 1.1:1), and pH=3 to prepare samples with total weight of 5 g.
Structures and Properties of Carbon Nanotubes/Thermosets Nanocomposites Subjected to External Electric Field during Cure Stage
Authors: Yang Jian Ping , Duan Jing Kuan , Fan Chang Xiu , Han Pei De , Shao Shuang Xi , Jiang Ping Kai
Published: March 2013

In this investigation, the multi-walled carbon nanotubes (MWCNTs) were dispersed in an interpenetrating polymer networks (IPNs) based on acrylate and cycloaliphatic epoxy resin (CER). The influences of the external electric field on the MWCNTs dispersion and the microstructure of host matrix were evaluated by means of optical microscopy, scanning electric microscopy (SEM) and atomic force microscopy (AFM), respectively. The microscopy measurements showed that the distribution of the MWCNTs depended strongly on the properties of the applied electric field. Applying AC electric field to the liquid MWCNTs/thermoset systems during curing stage could redistribute the MWCNTs, which arranged them in chain-like structures and oriented fibrous inclusions parallel to the applied electric field. However, the similar phenomenon was not observed in DC electric field. From the observations of AFM measurement, it was found that the utilization of the external electric field resulted in the nanostructured twophase structures in the resulting MWCNTs/thermoset nanocomposites. These novel electric-field-induced morphology transformations were mainly attributed to the curing process under the applied electric fields. The relationships between the microstructures and various physical properties of nanocomposites were also presented in this paper. The resulting nanocomposites displayed the interesting dielectric properties and the thermal stability properties, which significantly depended on their special microstructures of inclusions and the host matrix.
Evaluation of Pulsed Laser Deposited Li4Ti5O12  Thin Film Anodes by CV and EIS
Authors: Deng Jian Qiu , Lu Zhou Guang , Chung Chi Yuen , Wang Zhong Min , Zhou Huai Ying
Published: March 2013

Li4Ti5O12 thin film anodes were prepared successfully using pulsed laser deposition technique. The thin films were characterized by X-ray diffraction and environmental scanning electron microscopy. The effects of thickness and scan rate on the electrochemical properties of Li4Ti5O12 thin film electrodes were discussed in detail. The thin film anodes deliver favorable capacity and excellent cycling performance. The discharge capacity maintains at 141 mAhg-1 after 20 cycles at 1C charge-discharge rate for the thin film anodes deposited for 20 minutes. The charge-transfer resistances were also investigated by electrochemical impedance spectroscopy.
Performance Evaluation of a Silicide-Based Thermoelectric Generator for Power Generation
Authors: Zhou Ai Jun , Feng Li Dong , Liu Wei , Dai Xin Yi , Cui Heng Guan , Zhao Xin Bing , Li Jing Ze
Published: March 2013

A TEG composed of p-type higher manganese silicide and n-type magnesium silicide-stannide was evaluated by theoretical simulation based on finite element method and steady-state approximation. The geometry factors, heat flux, power output and the thermal electrical conversion efficiency of the TEG were calculated by applying the measured thermoelectric parameters of each leg into the simulation tool. Furthermore, the contact effect on the performance of the TEG was analyzed by separately introducing a contact layer between the thermoelectric legs and the metal layers having specific electrical and thermal conductivity. It was found that the different cross-sectional areas were required for the p-and n-type legs to achieve maximum module output or conversion efficiency. In ideal contact state, a promising efficiency of 8.29% can be obtained at a given temperature gradient. On the other hand, the performance of the TEG might be seriously deteriorated if the electrical or/and thermal resistance of the contact layer increased.
Influence of Crumb Rubber on the Drying Shrinkage and Plastic Shrinkage Cracking of AASM
Authors: Li Tao , Zhang Ya Mei , Zhu Zheng Gui
Published: March 2013

The alkali-activated slag mortar (AASM) has disadvantages of high shrinkage and therefore low crack resistance. In this paper, water quenched raw slag was used to replace sand for making AASM, and effects of crumb rubber on the drying shrinkage and plastic shrinkage cracking of AASM were investigated. The experimental results showed that the incorporation of crumb rubber into AASM reduced the drying shrinkage of AASM and improves the plastic shrinkage cracking resistance. Compared with the referenced mortar, after the 90-day drying the shrinkage of AASM containing 3% rubber decreased by 28.5% and crack index decreased by 64%. However, the addition of higher dosage of crumb rubber may bring negative effect on the flexural strength and the compressive strength of AASM. It is therefore proposed that the optimum rubber content be around 3% in order to balance both the mechanical performance and the plastic and the drying shrinkage.
Rapid Quantitative Identification of Thaumasite
Authors: Li Chang Cheng , Yao Yan , Wang Ling
Published: March 2013

To establish a quantitative identification method of thaumasite, internal doping method was used to accelerate thaumasite form of sulfate attack (TSA). A cement-limestone powder paste doped 10% of magnesium sulfate was immersed in water at (5±2) °C, while the blank was in 10% magnesium sulfate solution (by weight). Paste corrosion products were analyzed by infrared spectrum (IR), thermal analysis, nuclear magnetic resonance (NMR), and X-ray diffraction (XRD)/Rietveld refinement methods. The results show that the thaumasite formation was successfully accelerated by internal doping method. A lot of thaumasite formed after 6-15 months low temperature sulfate attack with gray mud-like material. IR analysis is able to be used to analysis thaumasite qualitatively, and Rietveld refinement was suitable to quantitative analysis of thaumasite. A rapid quantitative identification method of thaumasite including visual inspection, IR spectrum and XRD/Rietveld refinement was also established which will improve the accuracy and rapidness of TSAs research.
Preparation and Characterization of MnOX-CeO2/TiO2 Catalytic Material for SCR of NOX with NH3 at Low Temperature
Authors: Liu Qi Dong , Cui Su Ping , Guo Hong Xia , Wang Ya Li , Zhang Yun Feng
Published: March 2013

The MnOX-CeO2/TiO2 catalytic material for low temperature SCR of NOX with NH3 was prepared using aqueous solutions of three manganese salt as well as cerous nitrate and TiO2(anatase) powder by impregnation method. The properties of the catalytic materials were investigated by TG-DSC, XRF, XRD, XPS, BET and SEM. And the low temperature catalytic activity of the catalytic materials was measured. The results showed that, when manganese nitrate and manganese chloride and manganese acetate were used as precursors, respectively, the primary phases of catalytic materials were MnOx/MnO2, MnO2/Mn8O10Cl3 and Mn3O4/MnO2, the surface Mn/Ti molar ratio were 0.68, 0.19 and 0.88, the surface area were 45.1m2/g, 25.1 m2/g and 48.6 m2/g ,respectively. The optimum NOX conversion rate of catalytic material from manganese nitrate precursor and manganese chloride precursor and manganese acetate precursor were 97.9% at 483K, 86.6% at 513K, 97.2% at 423K, respectively. Consequently, the higher low-temperature activity of MnOX-CeO2/TiO2 from manganese acetate precursor may be attributed to higher surface and higher surface concentration of activity component.
Life Cycle Assessment of Ready-Mixed Concrete
Authors: Zhao Ming Nan , Gong Xian Zheng , Shi Fei Fei , Fang Ming Hui
Published: March 2013

Approximately 416.9 million m3 of concrete were used in China in buildings, roads and other constructions in 2009. This makes concrete one of the most common building materials on the market. While consuming large amounts of energy, concrete industry has also cause large burden on the environment due to the environmental emissions by the production of cement and the transport of materials. Therefore, more detailed quantitative studies are necessary to finally acknowledge its effects of energy and environment. The objective of this paper is to identify and quantify the energy consumption, and environmental emissions during all life-cycle phases of concrete in China by LCA.
Effects of Foreign Ions on Minerals of High Belite-Calcium Sulfoaluminate Cement
Authors: Li Juan , Zhou Chun Ying , Yang Ya Jin
Published: March 2013

The influence of foreign ions doping on the property of belite - sulfoaluminate (BCSA) clinker with belite and calcium sulfo-aluminate as main minerals was investigated. The research on four foreign doping ions with P5+, B2+, Ba2+, and Zn2+ was carried out. The mineral components were characterized by SEM, X-ray powder diffraction and Infrared. Some foreign ions entering into the lattice of β-C2S and during sintering at high temperature attained a high reactivity. The mechanism of the effect of these ions on stabilization and activation of minerals were clarified. Results revealed that P5+, Ba2+, and Zn2+ could stabilize and activate β-C2S as well as enhance reactivity of, but no positive effect of ion B2+ was observed. The sequence of influence of different ions on C2S is: Ba2+>P5+>Reference>Zn2+>B3+, and the sequence for was: P5+>Ba2+>Zn2+>Reference>B3+ . Compared to the 28-d compressive strength of reference one, P5+, Ba2+, and Zn2+ could enhance the strength by 15.6%, 8.9% and 26.5% respectively.
Al-Si-Mg-Cu Heat Storage Alloys and their Heat Storage Properties
Authors: Yu Si Rong , Xu Jun , Zhang Xiao Hua , Yao Qiang , Xu Shu Miao
Published: March 2013

The problems such as poor oxidation resistant properties at high temperatures and abated thermal storage capacities after repeated thermal cycles still exist in heat storage alloys. In order to alleviate these problems, orthogonal experiment was used to design nine Al-Si-Mg-Cu alloys in this work. An SII TG/DTA6300 differential thermal analyzer was used to determine the heat storage properties of these alloys. After integrating a series of factors, Al-12Si-2Mg-15Cu alloy was selected as the heat storage alloy. The oxidation test of this alloy at the temperature of 650 °C for 300 h was carried out, and the oxidation kinetics curve was obtained. The results showed that the oxide film was of good protection. This alloy exhibited a good thermal stability in view of the latent heat of fusion decreased 3.53%, the initial phase transition temperature decreased 0.1 °C, and terminated phase transition temperature increased 3.1 °C after 150 times of thermal cycles. The photomicrograph was used to discuss the reasons of the performance changes of this alloy.
Preparation of Polymer Capsules for Solid Hydrogen Storage
Authors: Gao Guo Feng , Yu Lian Yong , Yao Bin , Chen Ying Bo
Published: March 2013

Phase inversion of polymer solution by immersion-precipitation method was used to prepare porous hollow capsule nickel boride composite. The composite was used as a carrier for sodium borohydride, in which sodium borohydride was absorbed into the capsules or embedded in the capsules during the processing of capsules formation. The preparation method and adsorption property of the polymer capsules were studied. The effect of capsules structure on the storage capacity of sodium borohydride was investigated. The results showed that capsules prepared by 18wt% of PVDF-DMF solution with adding 15% PVP had the best adsorption capacity. While capsules prepared by PVA had better affinity to water, this made them easier to absorb sodium borohydride in the aqueous solution.
Bamboo Powder Liquefaction and Resinification: Application on the Phenolic Foam
Authors: Zhang Jin Ping , Du Meng Hao
Published: March 2013

Liquefaction products of bamboo powder were obtained by using phenol as liquefier and 3% sulfuric acid as catalyst. Biomass phenolic resin was formed by the reaction of bamboo powder liquefaction product and formaldehyde under alkaline condition. The yield and viscosity of resin prepared under various temperatures and resinification times were studied. The result showed that biomass phenolic resin included 2-8% of tween-80, 12-28% of p-toluenesulfonic acid, 12-28% of phosphoric acid, and 10-20% of n-pentane. The viscosity measured at the foaming temperature of 70 was 2000-4000mPa·s. The density of phenolic foam plastic prepared from biomass phenolic resin was 20.78-81.51kg/m3, and the compressive strength was 18-57N/cm2. Infrared spectroscopic analysis was also conducted on the biomass phenolic resin and phenolic foam.
Effects of Blended Steel Slag-Superfine Fly Ash Mineral Admixture and Ordinary Fly Ash on the Properties of Concrete
Authors: Wang Qiang , Yan Pei Yu , Liu Reng Guang
Published: March 2013

The effects of blended steel slag-superfine fly ash mineral admixture and ordinary fly ash on the properties of concrete were compared in this study. The results show that, in the case of the same adding amount, blended steel slag-superfine fly ash mineral admixture and ordinary fly ash have similar effects on the early strength and chloride ion permeability of concrete. Blended mineral admixture has higher ability to improve the late strength of concrete than ordinary fly ash. Paste and concrete containing blended mineral admixture have smaller porosities than that containing ordinary fly ash. Blended steel slag-superfine fly ash is an ideal mineral admixture for concrete.
Utilization of Blast Furnace Slag, Steel Slag in the Production of Clinker
Authors: Qin Shou Wan , Shen Jian Jun , Wang Hui Fen , Xiao Zhao Ran
Published: March 2013

The study on the use of blast furnace slag, steel slag and fly ash as raw materials to produce cement clinker has been carried out in the present investigation. The burnability of raw meal was determined by the linear shrinkage and free lime content of clinkers sintered at different temperatures. The microstructrue and properties of raw meal and clinker were investigated by the means of chemical analysis, X-ray diffraction and petrographic analysis. The physical and mechanical performance of cement was tested according to the standards. The results showed that the burnability was good as the free lime content was lower than 0.5w% in the clinker sintered at 1350. It is believed that the nucleation of alite only needs to grow bigger and rearrange with the rising temperature. The micrograph of clinker sintered at 1450 showed that there were some garlands of belite crystals around alite crystals because of high temperature or the local reducing atmosphere caused by the compact raw meal. High-quality cement clinker with compressive strength of 60.4MPa was produced by utilizing limestone, blast furnace slag, steel slag and fly ash as raw materials after curing 28 days.
Effect of Barium on Formation and Metastable Structure of Tricalcium Silicate
Authors: Ren Xue Hong , Zhang Wen Sheng , Wang Bin , Ye Jia Yuan
Published: March 2013

The effect of barium on the formation, structure and phase transition of tricalcium silicate (C3S) has been studied by X-ray powder diffraction combined with Rietveld method, Differential scanning calorimetry and Fourier transform infrared spectroscopy. The results showed that the low contents of barium was favorable the formation of C3S with up to 1.5% BaO. Higher amounts of BaO inhibited the C3S crystallization and lead to preferential formation of dicalcium silicate solid solution. Three triclinic forms T1, T2 and T3 of C3S were stabilized. The lattice parameters changed linearly to the barium content, however the discontinuity appeared at the phase transformation boundary, which follows the Vegards law. The crystallographic structure of T1 and T2 was similar to that of T3. The SiO44- tetrahedra were distorted in T1 and T2, while that was approximately regular tetrahedron in T3. The phase transitions of C3S were influenced by the incorporation of barium. It was believed that the stabilization of high temperature polymorphs of C3S was related to the lattice distortion caused by ionic substitution.
Fabrication and Characterization for Innate Super-Hydrophilic SiO2 Thin Films
Authors: Shen Kai Bo , Yang Huan , Liu Jian , Wang Wei , Huang Yue , Zhou Zhong Hua , Shen Shirley
Published: March 2013

Distinguished with photoinduced super-hydrophilic inorganic thin films, non-photoinduced innate super-hydrophilic SiO2 thin films were successfully fabricated in this work. The SiO2 sol was prepared by acid-base two-step sol-gel method. The mix solution containing SiO2 sol and polyethylene glycol (PEG) was coated on glass substrate and then went through thermal treatment to obtain innate super-hydrophilic SiO2 thin films. The films were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and contact angle meter. The results show that the surface concave-convex microstructure and the hydroxyl content are the factors that endow the SiO2 coating films with innate super-hydrophilic property.
Study on Preparation of Hard Elastic Polypropylene Fibers
Authors: Zhang Si Deng , Zhang Xu Zhen , Sun Bin , Chen Long , Ma Zhi Yan , Zhu Mei Fang
Published: March 2013

Polypropylene pre-oriented multifilament were made by melt spinning with fast winding, and then hard elastic polypropylene fibers were made followed by annealing treatment under some conditions. The effects of the conditions of melt spinning and annealing process on the elasticity of polypropylene fibers were studied. The structure and property of hard elastic polypropylene fibers were analyzed by DSC,WAXD,SAXS and Sound velocity anisotropy. The results showed that the hard elasticity of annealed fibers increased with the improving of speed of winding, and the elasticity also increased with the improving of annealing temperature and extension of annealing time, and the elastic recovery rate of PP multifilament can be as high as 93.6%. The crystal phase of unannealed and annealed PP fibers did not change. Annealing leaded to form perfectly the characteristic crystalline structure of crystals of being perpendicular to fiber axis.
Degradation Properties of Ti/Sb-SnO2 Electrodes Containing Different Intermediate Layers for Phenol
Authors: Zhang Zhen , Sun Qian Qian , Si Yin Ping
Published: March 2013

The electrocatalytic degradation performances of the Ti/Sb-SnO2 electrodes with Ni, Co and Mn intermediate layers prepared by thermal oxidation for phenol were studied. The microstructure and morphology of the intermediate layers and the outer active layers were characterized by XRD, SEM and EDX. The content of phenol and intermediate material degraded with different electrodes in the phenol solution was compared by UV-Vis spectrophotometer and measuring COD. In the meantime, the influence of different intermediate layers on the service life of anode was investigated by the accelerated life test. The experimental results showed that, after 10h, the phenol degradation efficiency with Ti/Ni/Sb-SnO2 electrode almost reached 100% and the COD was 18mg/L, but the electrode was irreversibly damaged within 20min under the accelerated life test. Comparing with Ti/Ni/Sb-SnO2, the degradation efficiency of phenol in Ti/Co/Sb-SnO2 electrode was worse because the COD was 43mg/L, but the accelerated life was 20.8h. For Ti/Mn/Sb-SnO2 electrode, the COD was only 50mg/L, but the accelerated life reached to 289h. Therefore it may be concluded that the different intermediate layers have a notable effect on the structure, morphology, service life and the electrocatalytic activity of anode.
Studying the Adsorption Performance in Binding of BTEX in the Air by Activated Carbon
Authors: Huang Hui , Wu Gui Ping , Yi Chuan
Published: March 2013

The adsorption experiment was carried out in an enclosed reactor in order to evaluate activated carbon, prepared by brewing yeast, which could remove benzene, toluene, ethylbenzene, and xylene (BTEX) from air. Various experimental parameters were determined, and activated carbon adsorption performance was compared with some commercial activated carbons (CACs). The results showed that lots of carboxyl, amino-groups and hydroxyl were on the surface of activated carbon, which were chemical reaction centers. Adsorption was reached equilibrium after six hours. The isothermal data of biosorption followed the Langmuir and Freundlich Models. When the temperature was 25°C,the maximum adsorption capacity was greater than the commercial activated carbon. These adsorption performances indicate that the activated carbon is a potentially economical adsorbent for BTEX removal.
Analysis on the CO2 Emission of Calcium Carbide Sludge as Secondary Raw Material in Cement Clinker Production
Authors: Shi Fei Fei , Wang Zhi Hong , Fang Ming Hui , Sun Bo Xue , Zhao Ming Nan , Cui Su Ping
Published: March 2013

With the development of economy, China has become one of the largest cement producers in the world. However, cement industry is a main contributor of global carbon emissions. Substituting calcium carbide sludge for limestone is an effective method for CO2 emission reduction in cement industry and has developed rapidly in recent years in China. The purpose of this study is to determine the life cycle CO2 emission of cement clinker produced with calcium carbide sludge as secondary raw material. The results show that compared with general cement clinker, the life cycle CO2 emission intensity of cement clinker produced with calcium carbide sludge will be decreased by 39.1% when substitution rate is 80%. And the CO2 emission results from the procedure of cement clinker production accounts for 85.7% of the total emission, in this stage, the CO2 emission declined by 42.2%.
Effects of LiClO4 on the Characteristics and Ionic Conductivity of the Solid Polymer Electrolytes Composed of PEO, LiClO4 and PLiAA
Authors: Yang Rui , Zhang Shi Chao , Zhang Lan , Bi Xiao Fang
Published: March 2013

Solid polymer electrolytes (SPEs) which were composed of poly (ethylene oxide) (PEO), poly (lithium acrylate) (PLiAA), and LiClO4 were prepared in order to investigate the influence of LiClO4 content on the ionic conductivity of the electrolyte. All of the membranes were investigated by XRD, DSC, and EIS, et.al. The dependence of SPEs conductivity on temperature was measured, and the maximum ionic conductivity is 5.88×10-6 S/cm at 293 K for membrane which is composed of PEO+PLiAA+15wt% LiClO4. The electrochemical stability window of the PEO+PLiAA+15wt% LiClO4 is 4.75 V verse Li.
Influence of Surface Modification by Nitric Acid on Activated Carbon's Adsorption of Nickel Ions
Authors: Liu Juan , Fan Hui Ping , Gong Guo Zhuo , Xie Qiang
Published: March 2013

Four kinds of commercial activated carbons were soaked in sodium hydroxide after modification with 10% nitric acid. Nickel adsorption isotherms for modified activated carbons before and after sodium hydroxide treatment were tested. The surface groups were characterized by the Fourier transform infrared spectroscopy and Boehm titration, the adsorption properties were determined by the iodine number and methylene blue number, the pHIEP were deduced by the Zeta potential analyzer. The results showed that nitric acid blocks the pore, while enhances the content of acid groups, especially carboxyl resulting in the decrease of nickel adsorption capacity. After sodium hydroxide treatment, the nickel capacity of activated carbon from anthracite, long flame coal, lignite and coconut increased by 21.5%, 116%, 78.9%, 89.1% comparing with the virgin activated carbon, respectively. The overall research indicated that nickel ion adsorption capacity of activated carbon can be improved only when the acid groups are transferred into anion, and the modification is more effective on the activated carbon prepared by low metamorphic grade coal.
Removal of Cationic Dyes by Polyphenylene Sulfide-Based Strong Acid Ion Exchange Fiber
Authors: Zhou Dong Ju , Li Xian Rui , Ni Hui , Yuan Si Guo
Published: March 2013

PPS-based strong acid ion exchange fiber was used to absorb cationic dye basic fuchsin and methyl blue in solution. The experimental results showed that the amount of methylene blue and basic fuchsin absorbed increased respectively with increasing of initial concentration from 100 to 600 mg/L. The adsorption capacity of the fiber was up to 604.81mg/g of basic fuchsin and to 618.94mg/g of methylene blue. The removal rate of the methylene blue reached 99.9% from 100 to 500mg/L, but of basic fuchsin from 100 to 300mg/L. Adsorption kinetic equation for basic fuchsin can be expressed as a pseudo-second-order dynamic process. The fiber is to be perfect prospect for the wastewater treatment because of its high adsorptive capacity and diffusion rate.
Preparation and Properties of Ecological Colored Cellulose Material
Authors: Xiao Wang , Huang Cheng , Wang Wen Sheng , Liu Guo Jun , Wei Chun Yan , Min Byung Gil
Published: March 2013

Ecological colored cellulose material was prepared via UV initiated photografting of acrylic acid/cationic dye system in this study. The colored cellulose material was characterized using scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR). The effects of monomer concentration, photoinitiator amount, dye amount, pH value, grafting time, heating temperature and grafting method on the coloration of cellulose material were discussed. The results showed that the optimum process was as follows: the monomer concentration of 50wt%, photoinitiator amount of 3o.w.m.%, grafting time of 4min, and heating temperature of 70.
Preparation of Corrosion-Resistant Ti/RuO2 Composite Powders
Authors: Duan Pan Qiao , Qin Guo Tong , Wei Wei
Published: March 2013

Ruthenium oxide coated titanium composite powders were prepared by precipitation of ruthenium salt to improve the resistance of titanium to corrosion. The composite powders were characterized by TEM and XPS. The results show that the ruthenium oxide is evenly deposited on the Ti powders. Corrosion test for the composite powders and Ti powders was conducted in 65% sulfuric acid (mass fraction). The composite powders exhibit good corrosion resistance. The corrosion rate decreased from 98.5% to 0.48% through modification. Ru/Ti molar ratio and annealing temperature have a major impact on the corrosion resistance.
Mechanisms of Phosphate Removal by Synthesized Calcite
Authors: Xu Nan , Yin Hong Wei , Chen Zhi Gang , Chen Ming , Liu Shou Qing
Published: March 2013

Calcite was synthesized through different drying processes, and characterized by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM). By bath experiments, the mechanisms of phosphate removal by synthesizing calcite were investigated. It showed that synthesis calcite had a strong capability to remove phosphate from solution. The adsorption of phosphate mainly depended on the total concentration of phosphate and pH in solution. Magnesium tended to the phosphate adsorption during pH range of 8-13.5; while it inhibited the adsorption at around pH 7. The experimental results suggested that the synthesized calcite with aged process could effectively remove the phosphate from an alkaline aqueous solution.
Preparation and Thermal/Fast Neutron Shielding Properties of Novel Boron Containing Ore Composites
Authors: Li Zhe Fu , Xue Xiang Xin , Duan Pei Ning , Tian Ang , Li Shu Xian , Yin Zheng Shuai
Published: March 2013

Four novel boron containing ores/epoxy composites were prepared by using nature ludwigite green ore (NLGO), artificial ores including boron containing iron ore concentrate (BCIOC), boron rich slag (BRS) and boron mud (BM) as neutron absorbers, which were obtained by dressing from NLGO, blast furnace separation from BCIOC and borax production, respectively. The microstructure of the composites was investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR). Shielding properties of the composites against thermal and Cf-252 fast neutron were measured. Factors affecting the shielding properties were investigated. Energy deposition, absorbed dose and half value layers of the composites against neutron penetration were simulated by Monte Carlo method, and a simulated function was obtained. The results showed that the composites were compact and the particles of ores were homogeneous. Ascending boron mole numbers per unit volume (nB) in the composites can obviously enhance the macroscopic absorbing cross section (Σthermal) and improve the shielding properties for thermal neutron. The relationship of Σthermal and nB follows the equation of Σthermal=0.218+450.490nB. And the relationship of average atomic number (Z) of boron containing ores composites and the macroscopic removal cross section for fast neutron follows the equation of Σremoval=0.042exp (-Z/5.70)+0.032. Enhancement of the shielding abilities against Cf-252 fast neutron can be achieved by using the composites with low average atomic number.
Study on Structure and Photocatalytic Properties of Cu2O Nanocrystal Synthesized by Low Temperature Liquid-Phase Method
Authors: Liu Ying Chao , Xue Jin Bo , Chi Cheng Zhong , Liang Wei , Li Guang Liang
Published: March 2013

Spherical and octahedral Cu2O nanocrystals were prepared by reducing copper acetate monohydrate (Cu (CH3COO)2·H2O) with hydrazine hydrate (N2H4·H2O) at ambient temperature and pressure. The influence of solution composition on the morphology and microstructure of Cu2O nanocrystals were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Ultraviolet and visible light spectrometer (UVvis) was employed to investigate the photocatalysis behavior of the Cu2O samples. The results show that Cu (OH)2 was initially formed with the addition of NaOH and then reduced into Cu2O by N2H4·H2O. At the same time, a portion of Cu2O particles were further reduced to Cu, but the increasing of O2 contents in the solution under vigorous stirring reconvert Cu into Cu2O whichlead to the formation of pure Cu2O nanocrystals. The alkaline condition which provided by NaOH was the prerequisite for obtaining spherical and octahedral Cu2O crystals. The facile method was provided to fabricate Cu2O nanocrystals with outstanding photocatalysis performance at low temperature, which may play an important role in sewage treatment and organic pollutants decomposition.
Effect of P(Bs-co-Cl) on Protein Content and Enzyme Activity in Earthworm
Authors: Xing Yong Lei , Zhang Min , Li Cheng Tao , Zhang Chi , He Wen Qing , Song Ji Qing
Published: March 2013

The natural soil-contact method was used to investigate the toxicity of poly (butylene succinate-co-caprolactone) (P(BS-co-CL)) copolymers with different number-average molecular weight (Mn) on the protein content, cellulose enzyme activity and peroxidase activity in earthworm extraction. The results showed that: during the first two weeks, both cellulose enzyme activity and peroxidase activity of earthworms treated by polymer (Mn is 8.0×103), decreased with the increase of polymer content. In the polymer (Mn is 1.6×104) group, in the end (28 and 42 d), cellulose enzyme and peroxidase activity decreased with the increase of the polymer concentration. However, the polymer (Mn is 2.8×104) had no significant effect on the cellulose enzyme activity and peroxidase activity of earthworms. In addition, in the beginning (7 and 14 d) of the three treatments, the protein content increased with the raising of polymer concentration. Nevertheless, in the test treated by copolymers with high Mn, there was no significant changing.
Application of the Soil Infiltration Method in the Reclaimed Water Reuse Technology
Authors: Di Peng , Wang Yin Jiao
Published: March 2013

The reclaimed water reuse is certainly the most effective method to alleviate the shortage of water resources in China at present. The reclaimed water reuse technique is now in the exploration and development stage in the urban area. At the present the reuse ratio is still low, the reasons may be that not only the processing system is very costly, but also a lot of fossil fuel is used, and a large amount of new solid waste and the second sludge will be produced during the reclaimed water reuse. In order to make the endurance of the environment meets the more severe challenges the soil infiltration method, based on ecology principle, through the use of sewage treatment combination process in soil infiltration method has been developed in the present study to solve the above problems. This paper emphasizing on the analysis of the advantages and disadvantages of the soil infiltration method in reclaimed water reuse technique to treat sewage, and provides a new idea and method for the development of water reuse technology.