bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Contact Metallisation on the High Temperature Characteristics of High-κ Dielectrics
Authors: Furnival Benjamin J.D. , Roy Sandip Kumar , Wright Nicolas G. , Horsfall Alton B.
Published: March 2013

In this work SiC-based MIS capacitors have been fabricated with different contact/high-k dielectric combinations and the temperature dependence of the characteristics have been examined in an N2 ambient at temperatures between 323K and 673K. The structures utilise either a Pt or Pd catalytic gate contact and a TiO2 or HfO2 high-k dielectric, all of which are grown on a thin SiO2 layer, thermally grown on the Si face of a 4H SiC epitaxial layer. The MIS capacitors have been studied in an N2 ambient between 323K and 673K and observations show that VFB reduces with increasing temperature. The majority of this variation is caused a reduction in the Dit influencing the structures electrical characteristics, due to a shift in the semiconductors bulk potential, which is due to the lower VTH of SiC-based MOSFETs at high temperatures.
Study on Reactive Species in Catalyst-Referred Etching of 4H–SiC using Platinum and Hydrofluoric Acid
Authors: Isohashi Ai , Sano Yasushi , Okamoto Takeshi , Tachibana Kazuma , Arima Kenta , Inagaki Kouji , Yagi Keita , Sadakuni Shun , Morikawa Yoshitada , Yamauchi Kazuto
Published: March 2013

In this study, we developed aA novel abrasive-free polishing method called the catalyst-referred etching (CARE) has been developed. CARE can chemically remove SiC chemically with using an etching agent activated by a catalyst. Platinum and hydrofluoric (HF) acid are used for the planarization of SiC substrates as a catalyst and etchant, respectively. CARE can produce an atomically flat surface of 4H–SiC (0001) with a root-mean-square roughness of less than <0.1 nm, regardless of the cut-off angle. However, the mechanism of CARE has hasis not yet been clarified to date. In this study, to clarify the mechanism, KF and NH4F are added to the etchant to clarify the mechanism. The An investigation of removal rate revealeds that the removal rate is proportional to [HF]×([F^- ]+[〖HF_2〗^- ]), and it is shown that both the HF molecule and fluorine ions (F− and HF2−) arethe reactive species of the CARE process are both HF molecule and fluorine ions (F- and HF2-).
Growth of Low-Defect SiC and AlN Crystals in Refractory Metal Crucibles
Authors: Helava Heikki I. , Mokhov Evgeny N. , Avdeev Oleg A. , Ramm Mark G. , Litvin Dmitri P. , Vasiliev Alexander V. , Roenkov Alexander D. , Nagalyuk Sergey S. , Makarov Yuri
Published: March 2013

Recently the wide bandgap semiconductors, silicon carbide (SiC) and aluminum nitride (AlN), have acquired increased importance due to the unique properties that make them applicable to a variety of rapidly-emerging, diverse technologies. In order to meet the challenges posed by these applications the materials need to be manufactured with the highest possible quality, both structural and chemical, at increasingly lower cost. This requirement places rather extreme constraints on the crystal growth as the simultaneous goals of high quality and low cost are generally incompatible. Refractory metal carbide technology, particularly, tantalum carbide (TaC), was originally developed for application in highly corrosive and reactive environments. The SiC group of Prof Yuri A Vodakov (for example, [1]) at Karmon Ltd in St Petersburg, Russia was the first to study and utilize the properties of refractory metal carbides, first for the growth of SiC and later for the growth of AlN. We discuss how the refractory metal carbides can answer many of the problems of growing SiC and AlN in a relatively simple and low cost manner.
Subnanosecond Semiconductor Opening Switch Based on 4H-SiC Junction Diode
Authors: Ivanov Pavel A. , Grekhov Igor V.
Published: March 2013

Mesa-epitaxial 4H-SiC p+-p-no-n+-diodes were fabricated and their reverse recovery characteristics were measured in pulse regimes to be relevant to DSRD- and SOS-modes of operation [I.V. Grekhov, G.A. Mesyats, Physical basis for high-power semiconductor nanosecond opening switches, IEEE Transactions on Plasma Science 28 (2000) 1540-1544]. It has been found that after short pumping the diodes by forward current pulse (5-ns duration, 200-A/cm2 peak current density) followed by applying the reverse voltage pulse (rise time 2 ns) the diodes are able to interrupt the reverse current density of 3.5 - 25 kA/cm2 in a time less than 0.3 ns.
Charge Pumping Analysis of Monolithically Fabricated 4H-SiC CMOS Structures
Authors: Martin Lucy Claire , Clark David T. , Ramsay E.P. , Murphy A.E. , Thompson R.F. , Smith Dave A. , Young R.A.R. , Cormack Jennifer D. , Wright Nicholas G. , Horsfall Alton B.
Published: March 2013

The development of silicon carbide complimentary metal-oxide-semiconductor (CMOS) is a key-enabling step in the realisation of low power circuitry for high-temperature applications. This paper describes investigations using the charge pumping technique into the properties of the gate dielectric interface as part of the development of the technology to realise monolithic fabrication of both n and p channel devices. A comparison of the charge pumping technique and the Hill-Coleman and Terman methods is also carried out to explore the feasibility of the technique.
900V, 1.46mOhm-cm2 4H-SiC Depletion Mode Vertical JFET
Authors: Chatty Kiran , Sheridan David C. , Bondarenko Volodymyr , Schrader Robin , Casady Jeffrey B.
Published: March 2013

We report a 900V 4H-SiC depletion mode (DM) VJFET with a specific on-resistance (RDSON,SP) of 1.46mOhm-cm2 at VGS=2.5V, IDS=10A. The RDSON,SP of the DM VJFET, designed for 600V-800V applications, is one of the lowest reported for a VJFET and is an order of magnitude lower compared to best Si Super Junction (SJ) MOSFETs reported in the literature. The turn-on (EON), turn-off (EOFF) and total (ETOTAL) switching energies of the DM-VJFET at VDD=400V, IDS=32.5A are 146uJ, 168uJ and 314uJ respectively. The switching figure of merit RDSON×QG is 3.8Ohm-nC; this is comparable to or better than the reported SJ-MOSFETs.
Reliable Operation of SiC Junction-Field-Effect-Transistor Subjected to over 2 Million 600-V Hard Switch Stressing Events
Authors: Steiner B. , Bayne S.B. , Veliadis Victor , Ha H.C. , Urciuoli D. , El Hinnawy N. , Borodulin P. , Scozzie C.
Published: March 2013

A necessity for the successful commercialization of SiC power devices is their long term reliability under the switching conditions encountered in the field. Normally-ON 1200 V SiC JFETs were stressed in repetitive hard-switching conditions to determine their fault handling capabilities. The switching pulses were generated from an RLC circuit, where energy initially stored in capacitors discharges through the JFET into a resistive load. The hard-switching included one million repetitive pulsed hard-switching events at 25 °C from a drain blocking-voltage of 600-V to an on-state current of 67 A, and an additional one million 600-V/63-A pulsed hard-switching events at 150 °C. The JFET conduction and blocking-voltage characteristics are virtually unchanged after over two million hard switching events proving the devices are reliable for handling high surge-current faults like those encountered in bidirectional circuit breaker applications.°
Reliability Evaluation of 4H-SiC JFETs Using I-V Characteristics and Low Frequency Noise
Authors: Chan Hua Khee , Stevens Rupert C. , Goss Jonathan P. , Wright Nicholas G. , Horsfall Alton B.
Published: March 2013

Two sets of 4H-SiC signal-lateral JFETs were thermally aged at 400°C and 500°C in furnaces open to air for 1000 hours. I"-" V and low frequency noise measurements were performed on these devices and the results were compared against the as-fabricated sample. The data from I"-" V characterisation demonstrates that the linear and saturated drain-source current decreases monotonically with stress temperature. In addition, the linear characteristics of the JFETs have shifted approximately 1.5V along the drain-source voltage axis. Whilst the devices thermally aged at 400°C show no degradation in magnitude and behaviour in Noise Power Spectral Density (NPSD), the NPSD of 500°C stressed devices has increase approximately 30dB and it shows a full frequency spectrum of 1/ƒ dependency up to 100 kHz. A further investigation of the noise origin reveals that the Normalised Noise Power Spectral Density (NNPSD) of the aged sample is directly proportional to RDS which is similar to the as-fabricated sample. Thus we hypothesize that the existing noise sources have intensified possibly due to the evolution of defects.
High-Temperature Characterization of 4H-SiC Darlington Transistors for Low Voltage Applications
Authors: Lanni Luigia , Malm B. Gunnar , Zetterling Carl Mikael , Östling Mikael
Published: March 2013

4H-SiC bipolar Darlington transistors (D-BJTs) for low voltage applications have been fabricated, simulated and characterized up to 300 °C, where they exhibit a current gain of 460. The influence on D-BJT current gain of relative current capability of driver and output BJTs has been investigated, and the collector resistance has been identified as the main limitation for the D-BJTs.
Optical Triggering of 12 kV 1 cm2 4H-SiC Thyristors
Authors: Rumyantsev Sergey L. , Levinshtein Mikhail E. , Shur Michael S. , Saxena Tanuj , Zhang Q.J. , Agarwal Anant , Cheng L. , Palmour John W.
Published: March 2013

We report on switch-on of 12 kV, 1cm2 optically triggered 4H-SiC thyristor fabricated by CREE Inc., to Imax=270 А with current rise time of ~ 3 s. Temperature dependence of holding current Ih in this thyristor has been experimentally studied in the temperature range from 300 to 425 K. It is shown that measurements of Ih temperature dependence under condition of optical switch-on at small anode bias and large load resistance reveal the existence of a ”weak point” within the optical window. This point is characterized by a much smaller critical charge than that within the remaining part of the window.
Effect of Fe on the Precipitate Characteristics and Out-of-Pile Corrosion Behavior of Zr-1Nb-xFe Alloys
Authors: Wang Rong Shan , Weng Li Kui , Zhang Yan Wei , Geng Jian Qiao , Du Chen Xi , Liu Er Wei
Published: March 2013

The effects of Fe addition on the precipitate characteristics and out-of-pile corrosion behavior of Zr-1Nb-xFe alloys, with x=0, 0.2 and 0.4 respectively, were investigated. The experimental results showed that the alloy with the composition of Zr-1Nb-0.4Fe had the best corrosion resistance and the alloy with the composition of Zr-1Nb-0.2Fe had the worst corrosion resistance. The relationship between the corrosion behavior and the microstructures including precipitate characteristics was discussed, and the elements contents, area fraction, as well as the mean diameter of the precipitate were analyzed. The β-Nb precipitate was found in Zr-1Nb alloy, both Zr (Nb,Fe)2 precipitate and β-Nb precipitate were formed in Zr-1Nb-0.2Fe alloy, while only Zr (Nb,Fe)2 precipitate was observed in Zr-1Nb-0.4Fe alloy. It has been found that the size of precipitates increased with the increasing of Fe content. This work indicated that the Fe content dominates the crystal structure, volume fraction and the element contents of the precipitate, which affect the corrosion resistance of Zr alloy.
Preparation and Thermoelectric Properties of Polyaniline Doped with Protonic Acids
Authors: Zhang Qing Li , Chang Yan Xia , Wang Lian Jun , Jiang Wan
Published: March 2013

Hydrochloric acid doped polyaniline and camphor sulfonic acid doped polyaniline were prepared by oxidative chemical polymerization and grinding, respectively. The structures of polyaniline samples were measured by Fourier transform infared spectroscopy. The Seebeck coefficient and electrical conductivity of the composites were investigated as protonic acid content in the temperature range from room temperature to 380K. The highest electrical conductivity of the 1M hydrochloric acid doped polyaniline reaches 5.57×102S/m at 320K, and the mass ratio of 1:1 camphor sulfonic acid doped polyaniline reaches 5.97×102S/m at 380K. This work suggests that a new method improves the thermoelectric properties of conducting polymers.
Influence of Artificial Aggregates on the ITZ's Microstructure of Recycling Concrete
Authors: Zhang Jun Hua , Zhou Zong Hui , Zhang De Cheng , Cheng Xin
Published: March 2013

Artificial aggregates with high-performance were prepared by the methods including steel slag, furnace slag, fly ash and coal gangue, and the recycling concrete was prepared by artificial aggregates instead of natural aggregates. This kind of concrete abandoned was able to completely regenerate cement, which will make the reuse of concrete possible. The composition and characteristics of the artificial aggregates will produce a significant effect on the interfacial transition zone (ITZ) in recycling concrete. The morphological features and mineral composition of three artificial aggregates were analyzed by SEM and XRD, and the ITZ of three recycling concrete and one ordinary concrete was investigated by SEM and EDS. The results showed that compared with ordinary concrete, although the recycling concretes ITZ had a small amount of CH crystal, most of the space was filled with dense hydration products. The interface width was 40μm, which less than 50μm of ordinary concrete. Artificial aggregates with different ratio of raw materials had a great effect on recycling concretes ITZ. The ITZ of recycling concrete prepared with 30% steel slag, 50% furnace slag, 20% fly ash had the smallest Ca/Si and much more C-S-H. the structure of ITZ was much denser and the microstructure was relatively better.
Research on Consolidation of Tailings by Microbially Induced Cementation
Authors: Li Long Zhi , Qin Chun Xiang , Rong Hui
Published: March 2013

The use of microbial cement to solidify tailings pile has been introduced and the tailings pre-product was made. In the laboratory, through the cementation performance test of small samples, the process parameters of the consolidation were discussed and some achievements in the use of tailings were developed.
Optimization Chemical Composition of the Blast Furnace Slag with Uniform Design
Authors: Wang Hui , Cui Su Ping , Shang Xiao Long
Published: March 2013

Using the industrial limestone, fly ash and pure chemical reagents as raw materials, the blast furnace slag was prepared in the simulation condition of the actual slag-making process. Using uniform design method, the influence of blast furnace slag composition factors such as quaternary alkalinity, ratio of CaO/MgO and ratio of SiO2/Al2O3 on the glass content of blast furnace slag were studied in the present in investigation, the relationship between glass content and the various factors has been obtained through regression analysis, and the main influence factors and the optimum blast furnace slag compositions been found out. The results showed that, the impact of various factors on the glass content of granulated blast furnace slag was quaternary alkalinity > ratio of SiO2/Al2O3 > ratio of CaO/MgO. According to the significance test of the regression equation and the verification experiment, it was concluded that the optimum compositions of granulated blast furnace slag were: the quaternary alkalinity was 0.85, the ratios of CaO/MgO and SiO2/Al2O3 were 11.5 and 6.5 respectively, and in this condition, the glass content of granulated blast furnace slag reached to 98.47%.
Finite Element Analysis of the Heat Transfer Problems of PCMs
Authors: Zhang Yi , Huang Bin , Li Dong Xu
Published: March 2013

Finite element method (FEM) was used for analyzing the heat transfer problems of the PCMs and phase change gypsum board. The simulation results showed that the heat transfer rate of composite PCMs (phase change materials) is higher than the PCMs, the mixture of diatomite improved the heat transfer performance of PCMs. Compared with blank gypsum board,the cold side temperature of phase change gypsum board was decreased, and the temperature rise rate of the cold side was also delayed. The cold side temperature difference between gypsum board and phase change gypsum board was decreasing as the ongoing of heat transfer process.
Deterioration of Cement-Fly Ash Composite Binder Materials Exposed to Elevated Temperature
Authors: Feng Jing Jing , Zhou Cui Ling , Wang Xiao Qing
Published: March 2013

The deterioration behavior of cement-fly ash composite binder materials exposed to elevated temperature was studied in the present investigation. With the temperature continuous rising, the surface microstructure evolution of cement-fly ash composite materials was observed in a real-time mode. And the pore structure of the hardened paste undergoing high temperatures was investigated by mercury intrusion porosimetry (MIP) test. The results showed that thermal cracking of hardened paste developed continuously from the surface to the interior and hydration products decomposed gradually with the increase of temperature. Both the processes make the pores of the hardened pastes become coarser as well as the significant increase of the porosity, hence leading to worse deterioration of the microstructure and decline of the strength. The experimental results showed that the morphological effect and micro-aggregate effect of fly ash could improve the microstructure of cement-fly ash composite materials effectively, and the active effect of fly ash reduced the content of calcium hydroxide in the paste significantly. Both of them make contributions to the high temperature resistance of cement-fly ash composite materials.
Study on Utilization of Biomass in Light-Weight Aggregate Production
Authors: Tian Run Zhu , Jiang Zheng Wu , Huang Qing Yun , Yang Zheng Hong
Published: March 2013

In this paper, the property of common biomass-rice husk was compared with that of coal. The combustion characteristics of rice husk were investigated by Thermogravimetry (TG) method, and the barriers for biomass fuels utilization as an alternative fuel to manufacture artificial aggregates were also analyzed. The key techniques of using biomass as an alternative fuel in light-weight aggregate production, such as preprocessing of the biomass feedstock, proper design of combustion system for biomass fuel and control of sintering process were proposed. Properties of artificial aggregates sintered by biomass fuel were also studied according to GB/T 17421.2-2010 test method, and the test results showed that all the properties meet the requirement of national standard.
LCI Study of SCR DeNOx Technology for Cement Industry
Authors: Li Chen , Cui Su Ping , Gong Xian Zheng , Meng Xian Ce , Sun Bo Xue
Published: March 2013

LCI study is short for life cycle inventory study. In the situation of more strict regulation limit of 500 mg NOx /m3 a demonstration project to reduce NOx emissions with clinker production capacity of 2000 t/d in Beijing is supported by the 'Five-twelfth' National Science and Technology Support Program of China Science and Technology Department. A selective catalytic reduction denitration (SCR DeNOx) technology is expected to be applied in this project. LCA models the life cycle of cement manufacturing with SCR DeNOx technology applied as its SCR system. The life cycle is from the coal and raw materials transportation, through the coal and raw meal grinding, to the clinker incineration, and finally the flue gas including NOx to the SCR reactor. The functional unit is 1 ton clinker. Data for cement produced in LNB technology as bench mark is analyzed and the SCR scenarios are to show that the SCR reactor can be established because the additional environmental impact is small due to small consumptions of reducing agent and electricity. SCR technology enable the deNOx efficiency much higher with small environmental impact.
Influence of Magnesium Additive on Mechanical Properties of Microbe Cementitious Materials
Authors: Rong Hui , Qian Chun Xiang , Li Long Zhi
Published: March 2013

Microbe cement is a new generation cement due to the ever increasing awareness of environmental protection. Microbe cement is a new strengthening material based on microbiologically induced precipitation of calcium carbonate. This paper presents the results from laboratory research on the influence of magnesium additive concentration (1.0mol/L3.0mol/L5.0mol/L and 7.0 mol/L) on the mechanical properties of microbe cementitious materials. In addition, the micro-morphology and microstructure of microbe cementitious materials were analyzed by scanning electron microscopy (SEM). The experimental results indicate that when the magnesium additive concentration was 1.0 mol/L, the compressive strength of microbe cementitious materials can reach up to 6.2MPa at an age of 12 days. The microstructure of microbe cementitious materials depends on the content of mineral produced by microbially induced precipitation.
Research and Development of Mineral Wool Production with High Temperature Industrial Residual Materials
Authors: Qi Guo Chao , Shan Feng Jun , Zhang Qu Kai
Published: March 2013

Mineral wool is a type of important material for basic infrastructure development and national economy. It is widely used as insulation material in construction industries. Some high temperature industrial solid waste materials, such as blast furnace slag, cyclone slag and some metal slag, after composition adjusting and reheating, can be directly used to produce mineral wool. The recycle of residual heat in the hot solid wastes can decrease the cost of mineral wool and is beneficial for energy conservation, environmental protection and social sustainable development. The development and technical characteristics of mineral wool production with blast furnace slag, cyclone slag and some non-ferrous metal slag have been analyzed in this paper, and the energy conservation technique in managing high temperature solid waste has been also discussed.
Effect of Monolayer on Performance of Cement Based Materials and its Acting Mechanism
Authors: Li Lei , Wang Wen Bin
Published: March 2013

Based on the self-assembly of amphiphilic molecular, the dense and stable monolayer was formed at the water/air interface on the cement based materials surface. The formed monolayer could reduce water evaporation significantly at plastic stage. The results of the capillary pressure and plastic shrinkage testing at horizontal direction indicated that the inflection point of capillary pressure beginning to increase was delayed and the plastic shrinkage was decreased, which might be the reason of the decreased crack risks. And the results from hydration degree and pore structure showed that both the hydration degree and pore composition were improved, which might be beneficial to cement based materials durability. This novel monolayer technique had great potential to dissolve the plastic crack problem of cement-based materials at Northwest of China.
The Preparation and Growth Mechanism of Ni-Coated TiH2 Composite Powder by Electroless Plating
Authors: Hou Jia Qian , Xiao Lai Rong , Guo Lei , Zhou Song Song , Wang Ruo Fan
Published: March 2013

The Ni-coated TiH2 composite powder was prepared by electroless plating and the concentration of reducing agent, reaction temperature, reaction time, PH value and so on were optimized by orthogonal experiment design. The Ni/TiH2 composite powder morphology and composition was analyzed by scanning electron microscopy (SEM), Energy Dispersive spectroscopy (EDS), X-ray diffraction (XRD); the plated Ni layer growth mechanism was explored preliminary. The Optimization technical parameters: the plating temperature was 85, the pH value was 10 and the hydrazine concentration was 100ml/L. Complete coating and uniform thickness of the Ni layer with average coating thickness about 2.0μm was successfully prepared with the optimization technical parameters. The growth mechanism of the coating followed the Ostwald ripening mechanism. Compared the TiH2 uncoated with Ni layers particles, the TiH2 composite powder could efficiently delay the starting time of gas release by approximately 80s.
Study on Treatment of Swine Wastewater by Sodium Type Mercerizing Zeolite
Authors: Liu Xue Yu , Song Yong Hiu , Lin Yu , Zhang Dong Na
Published: March 2013

The efficiency of swine wastewater treatment was studied by static experiment and dynamic experiment, using sodium type mercerizing as adsorbent. The optimum parameter condition for swine wastewater treatment summarized. The experimental results showed that the optimum parameters were pH=8.0, t=24h, T=25, 300 g/L zeolite in the static experiment. In dynamic experiment when the velocity was 6 BV/h, 12 BV/h and 24 BV/h, the penetrating capacity and volume of ammonia-nitrogen, phosphorus and CODCr were calculated. The removal efficiency of ammonia-nitrogen, phosphorus and CODCr was highest under the velocity of 12 BV/h. Penetrates capacity of ammonia nitrogen and phosphorus were 4.04 mg/g and 0.14 mg/g, penetrates volume were 29 BV and 58 BV, respectively.
Preparation and Characterization of Innate Super-Hydrophilic TiO2/SiO2 Thin Films
Authors: Yang Huan , Shen Kai Bo , Liu Jian , Wang Wei , Huang Yue , Zhou Zhong Hua , Shen Shirley
Published: March 2013

Unlike photo-induced super-hydrophilic inorganic thin films, non-photoinduced innate super-hydrophilic TiO2/SiO2 thin films have been successfully prepared in this work. SiO2/TiO2 thin films were prepared by solgel method via adding hydrophilic fumed silica to TiO2 sol and characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM) and contact angle meter. The results show that the super-hydrophilicity of the as-prepared thin films can maintain for one month without light irradiation, and the thin films have excellent antifogging property as well.
Preparation of Fly Ash/Rare Earth Adsorbent and its Adsorption for Reactive Dye from Aqueous Solution
Authors: Wang Chen , Li Bei Gang , Mi Jing
Published: March 2013

Lanthanum doped fly ash (La-FA) adsorbent was prepared using hydrothermal reaction method and applied to the removal of wool-used reactive red B (WRR B) dye from the aqueous solution. The preparation and adsorption conditions of the sorbent were investigated. The adsorption characteristics and mechanism were analyzed by X-ray diffraction (XRD) and discussed from kinetics viewpoint. The results show that: the removal rate of WRR B from the solution containing 150 mg/L at pH 6.0 by La-FA adsorbent, which obtained under the conditions of a certain ratio of mass to concentration of La3+ and stirring time of 6h at 60°C, is 94% with good adsorption effect when the contact time is 2.5h at temperature of 25°C. All sorption kinetic data at different temperature are found to be described by the pseudo-second order equation very well and the adsorption process is mainly controlled by intra-particle diffusion. The equilibrium adsorption amount (qe) of the La-FA adsorbent for reactive dyes increased with increase in dye initial concentration and decreased with the rise of temperature. The adsorption activation energy obtained was 9.86kJ/mol. Combining with XRD analysis, the results indicate that the adsorption is mainly the physical sorption with exothermic nature. The room temperature is favorable to the adsorption and actual operation.
Calculating Chinese Human Toxicity Potential Factors of Heavy Metals in Water for Material Industry
Authors: Wang Hong Tao , Gong Xian Zheng , Gao Feng , Sun Bo Xue , Li Chen , Xie Zhi Hui
Published: March 2013

With the development of materials industry, the problem of water pollution is increasingly serious, and therefore it is important to establish an appropriate characterization model of heavy metals in water in China. This paper provides the human toxicity potential factors of several heavy metals, including Hg, Cd, Cr, Pb and As. The result showed that Chinas HTP factors are partial greater than Europe factors, caused by the different industrial situation and the ratio of total human intake to total emissions.
A Study to the Factors Influencing the Plants' Absorption of Heavy Metals
Authors: Huang Jie Ying , Xu Xiao Chun , Chen Li Wei , Zhou Yuan Xiang
Published: March 2013

In order to master the rule of heavy metals migration on the interface of tailings-plants and how matrix physicochemical characteristics change, pot experiment was conducted with/without soil, choosing PAM and EDTA as tailings modifiers, with/ without organic matter. The results showed that: the existence of soil inhibited the absorption of heavy metals, especially for Cu, to which significant inhibition effect has been achieved,join of EDTA and PAM could further restrained the leafy plants to absorb heavy metals. The experimental results also indicated that PAM had a significantly adhesive effect on soil particles than EDTA,improved the soil structure to a certain role,each matrix pH value varies between 7-8, and there are no significant difference between PAM and EDTA processing matrix.
Dynamic Adsorption of Cr (VI) Ions from Aqueous Solution by Canna Edulis Ker Residue in a Fixed-Bed Column
Authors: Lin Shan , Lu Yu Dong , Lin Xiao Xuan , Wu Zong Hua
Published: March 2013

A continuous dynamic adsorption in a fixed-bed column was studied by canna edulis ker residue (CEKR) as an adsorbent for the removal of Cr (VI) ions from aqueous solution. The dynamic adsorption process was simulated by some mathematic models, to determine the characteristic parameters of the column. The results indicated that CEKR could effectively absorb Cr (VI) ions from aqueous solution. Breakthrough time reaching saturation increased significantly with the increase of the temperature, while the bed depth increased and the pH value decreased. In comparison, the initial metal concentration is able to slightly affect the adsorption. Some mathematical models could calculate the rate constants, correlation coefficients, the equilibrium adsorption and kinetic parameters, however, they were not suitable for the description the dynamic adsorption of Cr (VI) ions in the fixed-bed column.
Preparation and Characterization of Micro-Nanostructural Beads and the Super Hydrophobic Micro-Nanostructural Coating
Authors: Zhang Zhen , Zhao Hui You , Chen Yu Lin , Sun De Shun , Fu Cheng Song
Published: March 2013

Fly ash, as a raw materials,is used to prepare micro-nanostructural beads with the surface modified by using silane coupling agent. The coating of micro-nanostructural surface was prepared by using the modified micro-nanostructural beads and silicone rubber adhesive. Then the coating surface was dipped in liquid teflon (PTFE) for hydrophobic modification. Scanning Electronic Microscope (SEM) and JC2000C contact angle tester were used to character the coating surface performance. The results show that the average contact angle and rolling angle of the coating surface are measured as 152.9° and 3.4° respectively which means the prepared coating being of super-hydrophobicity.
Experimental Study of Diatomite Static Adsorption on TP Removal in Bovine Urine Wastewater
Authors: Li Xue Ying , Qu Guang Fei , Lin Yi Lu
Published: March 2013

Pollutions of livestock and poultry breeding to the environment have evolved into a serious social problem, while phosphorus is a non-renewable resource. This study aims to not only remove the phosphorus in bovine urine wastewater effectively, but also make it recyclable and reduce the load of the follow-up sewage disposal. Choosing the diatomite as the adsorption material, its adsorption effects and the influence factors of diatomite were investigated by static adsorption method, and the adsorption isothermal curves studied. The results showed that the best adsorption condition was as follows, i.e.,taking 50mL bovine urine wastewater with TP 45.67mg/L, when the diatomite dosage was 3.0g, the pH was 7.0, the adsorption time was at 6.0h with the temperature of 30, TP concentrations could be reduced to 9.86mg/L and total phosphorus removal rate reached at 78.41%. Freundlich equation was better than Langmuir equation in describing the behaviour of adsorption phosphorus on diatomite. It is believed that diatomite is feasible to be used as adsorption agent for phosphorus removal from bovine urine wastewater and this promotes the potential of diatomite being used as sewage treatment materials.
Hypercrosslinked Polymers Preparation VS Methylene Blue Adsorption
Authors: Zhao Lin Xiu , Yuan Si Guo , Sha Jiao , Li Shao Bin
Published: March 2013

In the study, two kinds of hypercrosslinked polymers were prepared by polymerization of dichloromethyl aryl monomer with benzene or itself. The chemical and pore structure of above polymers were characterized by FT-IR and BET. The results showed that these polymers possessed high BET specific surface area (up to 1000 m2/g) and large pore volumes (up to 1.2cm3/g). Two commercial polymer adsorbent (XAD-4, H103) and two new synthesized polymeric adsorbents (BE-XDC, CMB-CMB) have been used for the adsorption of reactive dye methylene blue (MB) from aqueous solution, and the static capacity followed an order as: CMB-CMB(142.77mg/g) > BE-XDC(104.61mg/g) > H103(71.01mg/g) > XAD-4(53.85mg/g). The Equilibrium adsorption data of the four polymeric adsorptions were obtained and fitted very well to Freundlich model. The adsorption equilibrium time of CMB-CMB, BE-XDC resin were less than 200min, which were faster than that of XAD-4, H103. The free energy changes, ΔG for adsorption of MB on the four polymeric adsorbents in the aqueous solution was evaluated. The negative values of ΔG indicated that the overall adsorption processes were spontaneous and thermodynamically favorable.
Effect of Temperature and H2S Concentration on Corrosion of X52 Pipeline Steel in Acidic Solutions
Authors: Liu Meng , Wang Jian Qiu , Ke Wei
Published: March 2013

The corrosion behavior of X52 pipeline steel in H2S solutions was investigated through immersion corrosion test which was carried out in a high temperature and high pressure autoclave at different temperatures and H2S concentrations. General corrosion rates were calculated based on the weight loss of samples. The morphology and the chemical composition of the corrosion products were obtained by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). The crystal structure of corrosion products was analyzed by X-Ray diffraction patterns (XRD). The corrosion products consisted mainly of the sulfide compounds (mackinawite, cubic ferrous sulfide, troilite and pyrrhotite). The corrosion products included two layers: the inner iron-rich layer and the outer sulfur-rich layer. Under H2S concentrations of 27g/L, the corrosion rate increased with the increase of temperature up to 90°C and then decreased at 120°C, finaly increased again. The corrosion rate first increased with H2S concentrations then decreased at 120°C. The structure and stability of the corrosion products due to different corrosion mechanism had a major impact on the corrosion rate. The corrosion resistance of the corrosion products increased as follows: mackinawite < cubic ferrous sulfide < troilite < pyrrhotite.
Preparation, Characterization and Properties of New Low Cost Multi-Channel Ceramic Membrane Tube for Water Treatment
Authors: Liu Rui Ping , Wang Chan Gan , Wang Yong Bin
Published: March 2013

Multi-channel tubular macroporous ceramic membrane supports were successfully prepared via a plastic extrusion method, using α-Al2O3 with a purity of 94wt% and aluminum hydroxide as starting materials, the ash of burned rice hull as the pore-forming agent and a small amount of talc and kaolin as sintering aids. The effects of the kinds of sintering aids, content of aluminum hydroxide and ash of burned rice hull on the porosity, pore size and distribution, compressive strength, acid and alkali corrosion resistance and permeability of the new multi-channel ceramic membrane supports were investigated. The results showed that aluminum hydroxide effectively improved the mechanical strength, and the support sintered at 1450°C for 4h with the aluminum hydroxide content of 20wt% exhibited higher performance: average pore size diameter and porosity were nearly 5μm and 50% respectively, the compressive strength was around 7MPa, the pure water flux was 26m3/m2h at 0.1MPa and changed to nearly 20m3/m2h after the acid and alkali treatment at 90°C for 48h. The support possesses excellent corrosion resistance and can be used in the water treatment process with large range of pH value.
Adsorption of Acetamiprid and Phenol from Water in Binary Components System with Adsorption Resins Modified with Proline
Authors: Wu Xiu Hong , Zhang Gen Cheng , Zhang Hong Mei , Xing Rong , Fei Zheng Hao
Published: March 2013

The adsorption of acetamiprid and phenol in water onto the resin of ZHP02 modified with proline based on NDA150 was investigated from the static experiment at different temperatures in single component system and binary components system. The adsorption capacities and adsorption selectivity for acetamiprid and phenol in waste water were tested. The results showed that the adsorption was fitted by Freundlich model, and the adsorption of acetamiprid or phenol on ZHP02 was an exothermic process. The cooperative adsorption existed in binary components system when the equilibrium concentration was higher. The adsorption of acetamiprid onto ZHP02 had little change in the presence of phenol, but the adsorption of phenol onto ZHP02 was weakened significantly in the presence of acetamiprid. The electrostatic force between acetamiprid and adsorbent was stronger than phenols, so acetamiprid was adsorbed preferentially onto ZHP02.
Preparation of Bionic TiO2 Structure Using Aquatic Plants as Template
Authors: Chen Zhi Gang , Liu Cheng Bao , Qian Jun Chao , Chen Feng , Gu Cheng , Ma Juan Ning , Li Ping
Published: March 2013

The bionic structure nanoporous TiO2 materials were prepared using aquatic plants as biological templates. The X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), nitrogen adsorption method and ultraviolet-visible light spectrometer were employed to characterize the structure of samples and the degradation performance of methylene blue solution under the visible light. The results showed that TiO2 sample inherited the porous structure of original template. Such bionic material was composed of ultra-thin piece layers which were full of TiO2 nanoparticles with size of about 10 nm. The product was studded with piled pores which had a few to dozens of nanoaperture. The material was doped with a small number of bionic legacy elements which can enhance the absorption of 400-800 nm range of the visible light, thus the bionic nanoporous TiO2 materials had better photocatalytic degradation effects of methylene blue solution in the sun.
Decolorization of Reactive Brilliant Red X-3B Simulated Dye Water by Novel Coagulants
Authors: Li Ji Zhou , Yuan Xu Yin , Tian Ming , Ji Hao Ran , Jiang Wan
Published: March 2013

Five novel coagulants, DC-491, Fennofix K97, BWD-01, MD-03 and MD-04 were chosen to treat reactive brilliant red X-3B simulated wastewater by jar tests. The results showed that the decolorization efficiencies were all higher than 75% at initial pH 8.2 and temperature 20 after 20 minutes of reaction. Then, two typical coagulants, BWD-01 and MD-04 which had better performance were chosen to study the effect of dye removal of X-3B at different operating parameters, including coagulant dosage, pH, sedimentaion time and reaction temperature of simulated wastewater. Decolorization efficiency of MD-04 for X-3B solution was higher than 80% in pH range from 3 to 9, while for BWD-01, efficiency increased from 37.3% to 82.3% in this pH range. For both BWD-01 and MD-04, the color removal efficiency increased as the solution temperature increased and the maximum efficiency was over 94% at 40. Small changes in the color removal efficiency were observed after 1 hour sedimentation for both coagulants.
New Seaweeds Coagulant Aids on Coagulation Performance and Floc Characteristics of Ferric Chloride Coagulant in Kaolin-Humic Acid Solution Treatment
Authors: Zhao Shuang , Gao Baoyu , Wang Yan
Published: March 2013

Using coagulant aid to increase the organics removal is one of the main methods to improve the coagulation effect. The development of new coagulant aids has vital significance to water supply and sewage treatment. This paper develops two kinds of new seaweeds coagulant aids- Enteromorpha extract (EE) and sodium alginate (SA), and then the two coagulant aids were used together with ferric chloride (FC) in humic acid - kaolin water sample. The coagulation aid effect of EE and SA were studied through the comparation of coagulation effects before and after the application of them. Meanwhile, the growth, breakage and regrowth of flocs were investigated by use of a laser diffraction particle sizing device. The experimental results showed that Ee had significant coagulant aid effect while the aid role of SA was not obvious, but when used together with FC, flocs showed larger particle sizes and growth rates no matter which coagulant aid was selected. Meanwhile the strength and recovery ability of flocs showed a corresponding increase.
Study on the Property of Silica Minerals Supported NanoTiO2
Authors: Song Bing , Zheng Shui Lin , Bai Chun Hua , Lu Fang Hui , Sun Zhi Ming , Qu Xiao Suo
Published: March 2013

In the study, porous amorphous silica minerals including Porous Silicon (PS), Diatomite Filter Aid (DFA) and Opal (Op) were chosen as carriers or supports to prepare TiO2/PS, TiO2/DFA and TiO2/Op composites by chemical co-precipitation method. The compound materials were characterized by SEM, TEM, and the photo-catalytic property of the prepared composites was investigated by degradation of Rhodamine B (RhB). Characterization showed that nanoTiO2 was coated on the surface of porous amorphous silica minerals. The crystal form of TiO2 was mainly anatase, and the size of which was nanoscale. Through comparative analysis, the photo-catalytic efficiency of TiO2/PS composite was the best, followed by TiO2/ DFA, and then TiO2/Op.
Wet-Purification of a Sodium-Based Bentonite
Authors: Zheng Shui Lin , Huai Yang Yang , Li Zhen Wei , Cui Hao Ran , Sun Zhi Ming
Published: March 2013

Bentonite mainly consists of montmorillonite, but is always associated with other impure minerals. In order to increase the montmorillonite content in raw bentonite from Xinjiang, this paper adopts wet-purification process which integrates the scrubbing process with streamlined centrifugalization. The optimum experiment condition is solid - liquid ratio (wv) 130, macerating time 20h, scrubbing time 10min, centrifugation time 13min, centrifugation velocity 1260r/min, ZHL dosage 0.4% and ZHC dosage 0.4%. According to the amount of methylene blue absorption raising from 64.5mmol/100g to 110mmol/100g and X-ray diffraction analysis, the montmorillonite content raises from 48% to 82%.
Influence of Cu Diffusion on Electrical Transport Properties of Bi0.5Sb1.5Te3
Authors: Chen Song , Wang Xin , Zou Zhi Gang , Cai Ke Feng
Published: March 2013

Bi0.5Sb1.5Te3 nanoplates from gas induced reduction (GIR) strategy were hot-pressed into bulk materials for thermoelectric properties investigation. During the electrical conductivity and Seebeck coefficient measurements, we found that the Cu from Cu electrodes diffused into samples when the measurement temperature was above 600 K. The phase composition and fracture surface of the samples before and after Cu diffusion were examined by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). We found that the Cu diffusion resulted in the composition deviation and formation of impurity phase, Cu1.8Te. When the electrical conductivity and Seebeck coefficient of the samples were measured again but below 600 K, the samples showed different electrical transport behavior and had enhanced power factors.
The Evaluation of Photo Catalytic-Membrane Reactor with Nanomaterials for Removing Virus
Authors: Chen Ya Nan , Zheng Xiang , Chen Di , Yang Ye
Published: March 2013

Nanometer photo catalytic-membrane reactor integrated photo catalytic technology with membrane separation technology was applied to remove virus existing in water. Bacteriophage f2 was used as surrogates for human enteric viruses. Two kinds of nanomaterials (TiO2 and ZnO) were selected as the catalyst. Three kinds of membranes interception performance for virus, adsorption efficiency of nanomaterial for virus, inactivated effect for virus with photo catalysis, and the comprehensive effect to f2 of photo catalytic-membrane reactor were studied under the transmembrane pressure of 20Kpa, with nanomaterial concentration of 100mg/L, light dose of 20mJ/cm2. It showed that the interception effect of flat membrane with casting was the best. the adsorption efficiency of the two kinds of nanomaterials was different, 1.478 lg and 0.201 lg for TiO2 and ZnO, respectively. The removal effect of the photo catalytic oxidation system to f2 was similar, both in 2-3 log. The removal efficiency of the photo catalytic-membrane reactor system has no obvious difference, both in 3-4 log, and it is improved significantly compared to the effect of individual photo catalysis and membrane separation. Further research indicates that: the elimination function of coupling system to f2 includes UV-inactivated, adsorption of nanomaterials, the inactivation of nanomaterials, the effect of oxide moiety which formed after nanomaterials absorbing ultraviolet light and membrane retention.
Experimental Study of Separating CH4/N2 by Using Coconut Shell Activated Carbon of High Temperature Roasting
Authors: Ma Dong Zhu , He Hong , Li Jian , Song Li Yun , Guo Lian Jie , Wang Hong Ming , He Wei
Published: March 2013

The effects on CH4 and N2 separation performance of coconut shell charcoal by high temperature roasting were studied. Results indicate that the surface area increased firstly and then decreased with the increasing of the roasting temperature, and it is found that surface area of roasting 4 hours is higher. Furthermore, the experiment focused on the effect of high temperature roasting on activated carbon adsorption volume and separation coefficient. It is obvious that the adsorption volume increases earlier and then decreases with the increasing roasting temperature, and there are obvious turning points to adsorption volume of CH4 and N2. Comparing various roasting time, it is found that adsorption volume in 4h is greater than that in 1h and also in 6h in the whole process. Separation coefficient decreases with increasing roasting temperature. When the temperature is higher than 800 , separation coefficient decreased rapidly. Considering the adsorption volume and separation coefficient, roasting 4 hours at 600 is selected for industrialized production.
Preparation and Properties of Micro/Nanostructural Polyaniline Doped with α-SiW11Co
Authors: Ma Rong Hua , Wang Ying , Ma Xue Hua , Ma Cheng Xin
Published: March 2013

Micro/nano-structural polyaniline were prepared by using thin glass tubes as template in the presence of α-SiW11Co and ammonium persulfate, which were used as dopant and oxidant, respectively, in this study. The structure and morphology of Micro/nano-structural polyaniline were characterized by means of IR, UV-Vis spectrum, XRD pattern and SEM images. The conductivity and fluorescence property were determined, and thermal stability was studied. The experimental results showed that the conductivity of the materials was 0.86 S·cm-1 at room temperature（20°C）. The images of scanning electron microscopy show that the materials have microspheres morphology. The spectra data indicate that polyaniline doped with α-SiW11Co exhibits fluorescence property. The photocatalytic degradation of gentian violet on α-SiW11Co/PANIin an aqueous solution was carried out to investigate the catalytic activity. The results indicated that the sensitizing effect of PANI can improve the light response of α-SiW11Co and enhance the separation efficiency of electron and hole pairs which in turn promotes the photocatalytic ability of the composites materials. This novel photocatalyst exhibits very high photocatalytic activities to decompose gentian violet in aqueous system under 30W ultraviolet light irradiation. After extraction, the photocatalytic activity under UV irradiation and gentian violet degraded by 90.41% within 150 min.