bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermoelectric Performance of Glass Microsphere Dispersed Bi-Sb Composites at Low Temperature
Authors: Chen Zhen , Han Ye Mao , Zhou Min , Huang Rong Jin , Zhou Yuan , Li Lai Feng
Published: March 2013

In the present study, the glass microsphere dispersed Bi-Sb thermoelectric materials have been fabricated through mechanical alloying followed by pressureless sintering. The phase composition and the microstructure were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. Electrical conductivity, Seebeck coefficient and thermal conductivity were measured in the temperature range of 77~300 K. The ZT values were calculated according to the measurement results. The results showed that the electrical conductivity, Seebeck coefficient and thermal conductivity decreased by adding glass microsphere into Bi-Sb thermoelectric materials. However, the optimum ZT value of 0.24 was obtained at 260 K, which was increased 10% than that of the Bi-Sb matrix. So it is confirmed that the thermoelectric performance of Bi-Sb-based materials can be improved by adding moderate glass microspheres.
Thermoelectric Properties of Al Doped ZnO Thin Films
Authors: Zheng Zhuang Hao , Fan Ping , Liang Guang Xing , Liu Peng Juan , Cao Peng Ju , Zhang Dong Ping , Cai Zhao Kun , Ou Xuan , Lai Cui Yuan
Published: March 2013

Significant progress has been made in thermoelectric materials during the last decades and it is found that thermoelectric thin film materials have high thermoelectric conversion efficiency. ZnO based thermoelectric materials, such as ZnO:Al (AZO), are considered as the most promising oxide materials for high-temperature, nontoxic and low-cost thermoelectric application. In this work, the effects of annealing temperature on the thermoelectric properties of AZO thin films prepared by direct current magnetron sputtering were investigated. The results indicate that the Seebeck coefficient of AZO thin films increases and the resistivity decreases as increasing of annealing temperature. Among the prepared AZO films in this work, the maximum absolute value of Seebeck coefficient is 460 μV/K and the minimum resistivity is 3.25×10-4 Ω·m. The sample annealed at 773 K has a maximum power factor value of 1.46×10-4 W/mK2 at 620 K with a moderate Seebeck coefficient of-355 μV/K and a electrical conductivity of 1.16×103 S/m.
Preparation and Performance Testing of Foamed Concrete
Authors: Yang Ting Song , Lu Ling Chao , Wang Shou De , Gong Chen Chen
Published: March 2013

The key influences of foamed concrete and the optimum preparation technology were studied. The performance of foamed concrete was analyzed by the compressive strength testing, SEM. Results show that the flowability of cement paste is good when water-cement ratio is 0.4. The amount of foam added in sulphoaluminate cement is not able to exceed 3.5L/kg. However, the dilution multiple of foaming agent is near concentration and the mixing time depends on the foam quantity. When the water-cement ratio is 0.4, the foam quantity is 3 L/kg and the foaming agent is diluted 30 times. When the mixing time is 60s, the dry density is around 380kg/m3 and the 7d compressive strength reaches to 0.9MPa.
Using Calcium Carbide Slag as One of Calcium-Containing Raw Materials to Produce Cement Clinker
Authors: Wang Ya Li , Dong Shi Jie , Liu Lin Lin , Cui Su Ping
Published: March 2013

Calcium carbide Slag is from CaC2 hydrolysis reaction and will do harm to land and make pollution. Calcium carbide slag can be a substitute for limestone to produce clinker with a high portion of CaO as an excellent calcium raw material. As a kind of industrial wastes, the properties of calcium carbide slag differentiate from that of natural limestone. In the present investigation, the modern analysis methods of XRF, XRD, DTA/TG, petrographic analysis were used to compare carbide slag and limestone, and the results showed that the main chemical compositions of the calcium carbide slag were basically the same with that of natural limestone. Comparing with limestone materials, calcium carbide slag had a higher content of CaO, and the main mineral phase constituent of limestone was CaCO3, whereas the main mineral of calcium carbide slag was Ca (OH)2 with a lower decomposition temperature. It has been found that under the same temperature the amount of C3S in the clinker of calcium carbide slag batching was slightly less than that of limestone batching.
The Phase Transformation of Recycling Concrete in Recalcination
Authors: Zhang Zhi Gang , Zhou Zong Hui , Zhang De Cheng , Cheng Xin
Published: March 2013

In this paper, the artificial aggregates were prepared by limestone and industrial wastes in accordance with the ratio of cement raw meal, to obtain the recycling concrete replacing natural aggregates. Cement clinker could be regenerated by these recycling concrete and the aim of recycling could be realized. After these concrete was cured for 90 days, then was crushed and grinded, the phase transformation of recycling concrete in recalcination would been studied by XRD and so on. The experimental results showed that the composition of the recycling concrete met the demand of clinker modulus and C2S, C3S, C4AF, C3A were well crystallized at 1400 °C. So these recycling concrete could be directly calcined. The calcium hydroxide dehydrated around the temperature of 500°C. The calcium silicate hydrate was dehydrated gradually between the temperature of 400°C and 1000°C. At the same time, C2S crystallized during the temperature range. C4AF and C3A stared to crystallize around the temperature of 1000°C. Due to the composition of these concrete was complex, the lowest eutectic temperature dropped. C3S started to crystallize around the temperature of 1250°C and the best crystallization was achieved at the temperature of 1400°C.
Effects of Water Absorption and Size of Superabsorbent Polymers on Internal Curing of Cement Paste
Authors: Wang Wen Bin , Liu Ji Ping , Tian Qian , Wang Yu Jiang , Li Lei
Published: March 2013

In recent years, superabsorbent polymers (SAPs) are considered as promising material for internal curing of cement-based materials, however, the relationship between SAPs structure and its performance are still unclear. In this paper, SAPs with different water absorption and size were selected to discuss their effect on autogenous deformation of cement paste and strength of mortars. Results indicated that SAPs with large-size and high-water absorption had positive effect on autogenous shrinkage reduction. The influence of SAPs on mortar mechanical properties revealed that SPAs seemed to have no negative effect on the strength of cement past. The increase of the strength might be from the decreased water/cement (w/c) ratio due to the water absorption by SAPs.
Reactant Concentration and Carbonization to the Controllable Fabrication of Carbon Aerogels
Authors: Feng Ya Ning , Ge Li Ling , Jiang Bai Ling , Miao Lei , Tanemura Masaki
Published: March 2013

To improve the controllability of the fabrication of carbon aerogels, the effects of the concentration of the reactant (RF%) on the structural properties of organic resorcinol formaldehyde (RF) gel and the effects of the carbonization temperature on nanostructure of carbon aerogels were discussed. The concentration of the reaction was turned from 5%,10%,20%,30%,40%,50%,55% and 60% to prepare the samples. The RF aerogels were carbonized at temperature of 700, 900 and 1050. The shrinkage and nitrogen gas adsorption were measured. Experimental results showed that the structural stability of the organic RF aerogel can be improved by decreasing the shrink in drying process and increasing the condensation of reactant in the starting solution to a certain value, such as 55%. The ordered pore size distribution of carbon aerogels with less structure defects is able to be produced through the effective particle fusing at the carbonization temperature as high as 1050.
Reducing Benzo(a)pyrene Content of Coal-Tar-Pitch Modified by Styrene-Butadiene Rubber through Dynamic Vulcanization
Authors: Ouyoung Chun Fa , Li Xiang Yong , Gao Qun , Shan Xiao Qian , Shi Yu Tao , Zheng Kang Sheng , Zhao Ling Di
Published: March 2013

Coal tar pitch (CTP) mainly consists of polycyclic aromatic hydrocarbons (PAHs), some of which are carcinogenic. Among PAHs, benzo (a) pyrene (BAP) as one of the most prominently reported carcinogens which present in CTP causes the concerns of environmentalists. In this work, CTP was modified by styrene-butadiene rubber (SBR) through dynamic vulcanization. Ultraviolet-visible spectrophotometry (UV-VIS) was used to measure the content of BAP. After SBR modification through dynamic vulcanization, the BAP content have been reduced to 50%. With increasing the content of SBR,the content of BAP further reduced. The light component of the modified CTP decreased by the SBR modifier,verified by Headspace gas chromatography-mass spectrometry (GC-MS). Meanwhile, the SBR modifier has improved physical properties of the CTP, such as softening point, ductility, flowing property at high temperature. When the SBR content reached to 6 from 5.5, the softening point increased dramatically to 99 from 50.5. Thus, the modified CTP has various potential applications such as road pavement and carbon binder.
Study on the Preparation and Performance of a New Alkali-Free and Chloride-Free Liquid Accelerator
Authors: Ma Zhong Cheng , Wang Lan , Ma Jing Yu
Published: March 2013

Accelerators have taken an important role in preparation of shotcrete. The preparation method of a new chlorine-free and alkali-free liquid accelerator was amplified, and its effects on cement setting time, mortar strength and other performances were studied. The results showed that the preparation accelerator was transparent liquid, alkali-free, chlorine-free, stabilization, and long time not to layer. When the addition ratio (in mass) of accelerator is more than 4%, such performances like setting time and mortar strength of cement reach the requirement of JC477-2005 standard. The 1d compressive strength of cement mortar was up to 14Mpa, and 28d compressive strength doe not decrease.. The best addition ratio of this accelerator is 4% to 6%.
Experimental Study on the Pumice Aggregate Concrete
Authors: Lv Xing Jun , Cao Ming Li , Li Yan , Li Yong
Published: March 2013

Pumice is a kind of natural lightweight aggregate with well-developed porosity and moderate-intensity. Amorphous Si-Al oxide is its main mineral composition. This paper focused on the performance and features of the pumice pozzolan and aggregate firstly. Then a kind of pumice concretes was prepared with the ordinary Portland cement, ordinary sand and strengthened coarse pumice aggregates. And its mechanical properties, durability, insulation and absorbing performance were investigated. The result showed that the compressive strength of pumice concrete was 20MPa, anti-freezing durability was more than 100 freeze-thaw cycles, electric flux within 6 hours was 1749C, thermal conductivity coefficient was 0.318W/ mK, and the electromagnetic wave absorption was-5dB ranging from 8 to 18GHz. The results indicated that the pumice concrete could be developed as the green and multi-functional concrete materials in the future.
Surfactants Effect on the Photoactivity of Fe-Doped TiO2
Authors: Chen Qing Yun , Xue Chao , Li Xiang Lin , Wang Yun Hai
Published: March 2013

Ti (OC4H9)4 was used as the Ti precursor and titanium dioxide (TiO2) was prepared by sol-gel method. During the preparation process, Fe3+ was doped and different surfactants, such as SDS, PEG, CTAB, were added to improve the photocatalytic activity of TiO2. The effect of the different type of surfactants on the structure of Fe-doped TiO2 was discussed. The photocatalysts were characterized by thermogravimetric thermal analysis, X-ray diffraction, scanning electron microscopy and UV-Vis spectrophotometer. The red shift of the absorption edge of the Fe-doped TiO2 prepared by using different surfactants was observed. Methyl orange (MO) solution was degraded under sunlight irradiation to evaluate the photocatalytic performance. The results indicated that the photocatalyst prepared with PEG addition had the highest activity and MO degradation ratio could reach 90% after 4 hours irradiation with the best photocatalyst.
Study of Pore Property of Mesoporous Films Materials for Trace Explosive Detection
Authors: Ma Li , Wen Yu Quan , Yan Nan , Li Guang Tao
Published: March 2013

Thus, here, by using the sol-gel technique and spin coating technology, a series of mesoporous silica thin films doped by silylated naphthol fluorescence dye were successfully fabricated. By selecting the same surfactant triblock copolymer Pluronic F127 (EO106-PO70-EO106) as structure-directing agent, films with different pore structure and similar aperture size were synthesized under different conditions. The films doping fluorescence dye toward nitro explosive 2, 4, 6-trinitrotoluene (TNT) vapor exhibited rapid response rate and extremely high fluorescent quenching efficiency, close to 96.4 % after 1200 s response. The results clearly showed that pore structure control of mesoporous film was an effective way to improve sensor performance. Mesoporous thin films, with different pore structure, easily to be prepared and owning high sensitivity, could be used as a new alternative of trace explosive detecting material.
The Removal and Inhibitory Effect of CNTs on Model Viruses
Authors: Liu Shi Yuan , Zheng Xiang , Yang Ye , Liu Jia , Li Jie
Published: March 2013

Nanomaterial is becoming an important adsorption or disinfection material for removing virus from drinking water. In this study, static and dynamic tests were used to examine adsorption and inhibition characteristics of carbon nanotubes (CNTs) on two model viruses -- f2 and MS2 bacteriophage. Controlling variate method was used to systematically investigate the adsorption kinetics and adsorption isotherms of CNTs on two model viruses; as well as to find the impact of different CNTs dosages on adsorption effect; and then to study the inhibitory effect of CNTs.The results showed that: (1) The adsorption process of f2 and MS2 bacteriophage on CNTs corresponded well with the pseudo-second-order kinetics equation. Time to reach a saturation equilibrium adsorption is about 30min. (2) Both the Langmuir and Freundlich isotherm adequately described two adsorption processes which indicated that the removal mechanism of virus was a mix of monolayer and multilayer adsorption. (3)The dosage of a single removal system should not be too high in practical application. (4) The inhibition of CNTs on model viruses exhibited.
Preparation and Characterization of Chemical Bath Deposited CdS Thin Films for Solar Cells
Authors: Xie Zhen Hai , Li Jian Kang
Published: March 2013

Chemical bath deposition of CdS thin film for solar cells was investigated in this study. CdS thin films were prepared by chemical-bath deposition (CBD) from a bath containing cadmium acetate, ammonium chloride, ammonium hydroxide and thiourea in aqueous solution on the glass substrate at certain bath temperature. The characterization of samples was conducted by using different methods such as scanning electron microscopy (SEM), X-ray diffraction (XRD) and ultraviolet spectrophotometry (UV). The crystal quality of CdS thin films was improved after CdCl2 thermal annealing at 400C. The results showed that chemical bath deposited CdS thin film was symmetrical and compact, but depositing rate was low. As a result, the best deposition conditions were summarized, such as the pH value was about 10.5, depositing time was 60 minutes.
First-Principles Studies on the Structures and Properties of Ti- and Zn-Substituted Mg2Ni Hydrogen Storage Alloys and their Hydrides
Authors: Hou Xiao Jiang , Kou Hong Chao , Zhang Tie Bang , Hu Rui , Li Jin Shan , Xue Xiang Yi
Published: March 2013

In order to study the improvement mechanism of transition metal elements on Mg-based hydrogen storage alloys, especially for the structures and properties of hydrogen storage alloy Mg2Ni, Ti and Zn substituted alloys Mg2-mMmNi,Mg2Ni1-nMn (M=Ti and Zn, m, n=0.1667), and their hydrides Mg2NiH4,Mg2-mMmNiH4,Mg2Ni1-nMnH4(M=Ti and Zn, m , n=0.125) have been investigated by first-principles. Through analyzing the results of the crystal structure, electron density distribution and density of states, the changes of structures and properties resulting from the adding of transition metal elements Ti and V of intermetallic Mg2Ni and its hydride Mg2NiH4 were investigated. The results showed that the addition of transition metal elements can reduce the stability of the Mg2Ni system to varying degrees and improve the dehydrogenation dynamics performance. Therefore, it may be considered that the substitution by transition metal elements in Mg-based hydrogen storage alloys is an effective technique to improve the thermodynamic behavior of hydrogenation/dehydrogenation in Mg-based hydrogen storage alloys (HSAs).
Desulfurization and Regeneration Performance of Sorbent Prepared by Subcritical Water Impregnation
Authors: Qin Hao Chen , Liu Lian Wei , Si Wei Ping , Chang Li Ping , Bao Wei Ren , Han Li Na
Published: March 2013

A series of metal oxides sorbents supported on γ-Al2O3 were directly prepared by subcritical water impregnation (SCWI) method using an autoclave reactor. The effects of active components, preparation pressure, temperature, and time on the desulfurization activity of sorbents in hot coal-based gases at mid-temperature were investigated. The samples were characterized by X-ray diffraction (XRD), nitrogen adsorption and atomic absorption spectrophotometer (AAS). The results showed that Mn-based sorbent loaded on γ-Al2O3 by SCWI presented a good desulfurization performance. The optimal preparation parameters of sorbent were the temperature of 350 °C, the pressure of 18.9 MPa, impregnation time of 30 min, the precursor solution concentration of 0.287 mol/L and the volume of 100 ml, respectively. The Mn/γ-Al2O3 sorbent prepared under the optimal conditions presented a good desulfurization precision and regeneration performance. After regeneration, the mechanical strengths of the sorbents were higher than that of raw support and the breakthrough time at the desulfurization efficiency of above 99% was not obviously decreased.
In Situ Synthesis of Cu-SAPO-34/Cordierite with Ultrasonic Treatment and its Property of NOx Removal
Authors: Gao Zhi Juan , Bao Wei Ren , Chang Li Ping , Wang Jian Cheng
Published: March 2013

A Cu-SAPO-34/cordierite monolithic catalyst was prepared by in-situ hydrothermal method. The effects of ultrasonic treatment were mainly investigated during the preparing process. The removal of NOX was evaluated using a fixed-bed reactor. X-ray diffraction, scanning electron microscopy were used to characterize the samples showing that the crystallinity of Cu-SAPO-34 molecular sieve have increased after ultrasonic treatment. The Cu-SAPO-34/cordierite prepared by ultrasonic treatment showed higher de-NOx activity and stronger anti-aging property. NOx conversion could reach more than 80% between 440 and 560°C over the fresh Cu-SAPO-34/cordierite catalyst with ultrasonic treatment (600 W, 2 h) and the highest conversion was 86%, however, the highest conversion was only 76% over the Cu-SAPO-34/cordierite catalyst without ultrasonic treatment. After aging (treated for 15 h at 720 °C in the presence of 200 ppm SO2 and 10% vapor), NOx conversion reached more than 45% between 400 and 520 °C over the catalyst with ultrasonic treatment and the highest conversion was 57%, however, the highest conversion was only 43% over the catalyst without ultrasonic treatment. The XRD and SEM results indicated that the structure and morphology of Cu-SAPO-34/cordierite monolithic catalyst kept in good condition after aging.
Research of Lithium Ferrous Phosphate by Microwave Technique
Authors: Li Jun Yan , Zhao Hai Yan , Qu Guang Fei , Gu Jun Jie , Ning Ping
Published: March 2013

In order to developing high-value-added products and making full use of phosphate resources, Lithium Iron Phosphate were synthesized in the controlled atmosphere, using electronic grade phosphoric acid from Yunnan province, ferrous oxalate and Lithium carbonate by microwave processing. The variety of particles and distribution in different conditions of the mixing and grinding, the influence of appearance and property of the Lithium Iron Phosphate in different conditions of microwave power, microwave time and reaction temperature were discussed. Based on the experiment the optimized process conditions have been obtained. Some of the samples were characterized by XRD, SEM, electric capacity, chemical analysis, cycle performance and phase analysis. The experimental results show that the microwave synthesis method of Lithium Ferrous Phosphate is feasible.
Removal of Cr (VI) from Aqueous Solution Using Camellia oleifera Abel Shells
Authors: Lu Yu Dong , Wu Wen Lu , Lin Shan , You Rui Yun , Wu Zong Hua
Published: March 2013

The use of camellia oleifera abel shells as biosorbent has been successfully demonstrated in the removal of Cr (VI) from aqueous solution. The effects of different parameters, such as, contact time, initial concentration of Cr (VI), pH and temperature on Cr (VI) adsorption were investigated. The results showed that the maximum uptake of Cr (VI) was up to 190.69 mg/g at a pH value of around 1.0, under the initial Cr (VI) concentration of 400mg/L and at the temperature of 298 K. The adsorption kinetics could be described by pseudo-first order and pseudo-second order kinetics models.
Kinetics and Thermodynamics of Cd(II) Sorption onto Sodium Alginate/Poly(Vinyl Alcohol)/Hydroxyapatite Composite Fiber
Authors: Yang Zi Ze , Xiao Wang , Ma Chun , Lv Li Hua , Wei Chun Yan , Min Byung Gil
Published: March 2013

In this paper, the sodium alginate (SA)/poly (vinylalcohol)(PVA)/hydroxyapatite (HAp) fiber was prepared via solution spinning. The adsorption properties of SA/PVA/HAp composite fiber were studied,and the adsorption kinetics and isotherms were investigated. The experimental results showed that the adsorption process was fast, in which half-equilibrium and equilibrium was obtained in 5 and 30 minutes, respectively. The pseudo-second-order kinetic model provided a better correlation of the experimental results. Both of Langmuir isotherm and Freundlich isotherm could describe the adsorption behavior of SA/PVA/HAp composite fiber towards cadmium. The positive H° value and increased absolute value of the G° with temperature indicate that high temperature is good to the adsorption process.
In Situ Synthesis and Characterization of Nanosize Hydroxyapatite/Polyacrylonitrile Composite Bead
Authors: Xu Ming Mei , Xiao Wang , Cui Yong Zhu , Shao Wei , Sui Yan Ling , Byung Gil Min
Published: March 2013

nanosize hydroxyapatite/polyacrylonitrile composite bead was prepared via in-situ synthesis method. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), particle size measurement and X-ray diffraction (XRD) were used to characterize the HAp/PAN composite bead. XRD curve indicates low crystallinity of HAp. Particle size and SEM analysis demonstrates that decreased partical size of synthesized HAp as well as good distribution with the addition of PAN is found. The HAp is well-distributed and the combination between HAp and PAN is well. FTIR showed that there was no shift of characteristic peaks of synthesized HAp in PAN, which proves the physical interaction between PAN and HAp. The approximate HAp content of 28.6% calculated from thermal analysis curves means high conversion ratio of HAp. The adsorption amount of cadmium ions onto composite beads is lower than HAp particles.
Analysis on Life Cycle CO2 Emission of Aerated Concrete Production in China
Authors: Fang Ming Hui , Wang Zhi Hong , Shi Fei Fei , Sun Bo Xue , Zhao Ming Nan , Cui Su Ping , Meng Xian Ce
Published: March 2013

Aerated concrete is a new type of wall material with beneficial features like light weight, heat insulation, fire prevention and low energy consumption. As a key milestone in wall materials innovation and energy-saving of building system, it has been proven to be an ideal wall material which can replace traditional clay brick through years of application and practice. This study calculated the CO2 emissions in all the stages of life cycle of aerated concrete production. Compared with clay brick, the life cycle CO2 intensity of aerated concrete block will be decreased by 67.4% with the same insulation effect. Study on the environmental loads of aerated concrete industry will provide theoretical base for the carry out of energy-saving and emission reduction, the formulation of clean production and the development of recycling economy.
Thermodynamic Study on the Adsorption of Nickel Ion onto Activated Carbons
Authors: Liu Juan , Liu Jin Chang , Yao Xin , Xie Qiang
Published: March 2013

The adsorption isotherms and kinetics of nickel ion onto commercial activated carbons were determined and investigated under different temperature and initial pH in solution. The pore size distribution, specific surface area and functional groups of activated carbons were characterized by N2 adsorption isotherms and Boehm titration. The results showed that the nickel ion adsorption property of activated carbon from precursors including anthracite, long flame coal, lignite and coconut were 4.9, 3.4, 4.1, 5.2mg/g, respectively. There was no obvious correlation with surface area, total volume or surface functional group value. The nickel ion adsorption isotherms and kinetics fitted the Langmuir isotherm and pseudo-second-order model very well. The adsorption was a spontaneous endothermic process, in which the adsorption took place primarily due to the ion-exchange action in low concentration of 50mg/L. On the other hand, the adsorption depended on the physical adsorption when the concentration100mg/L. The nickel ion adsorption capacity was highly affected by solution pH, and the optimum initial pH ranged was from 4 to 7.
Synthesis and Activity of Ag-Doped Bi2WO6 Photocatalysts
Authors: Chen Ran , Hu Chao Hao , Wei Shuai , Xia Jin Hong , Cui Jian , Zhou Huai Ying
Published: March 2013

Ag-doped Bi2WO6 photocatalysts were synthesized by hydrothermal method using from Bi (NO)3·5H2O, NH4VO3, and AgNO3 and further characterized by X-ray diffraction, Scanning electron microscopy, Energy dispersive X-ray detector (EDS) and UV-Vis diffusion reflectance spectra techniques. The photocatalytic activity of Ag-doped Bi2WO6 photocatalysts was evaluated by degrading RhB (10 mg/L) under visible light irradiation (λ > 420 nm). The results showed that in comparison with pure Bi2WO6 the photocatalytic activity of Ag-doped composite photocatalysts was improved significantly, and the degradation rate of RhB was increased about 26% when the Ag+ dopant concentration was 15%.
Kinetics and Thermodynamics of Sodium Alginate/Hydroxyapatite Composite Adsorption Fiber for Cd(II) Adsorping
Authors: Song Zhi Yun , Xiao Wang , Hao Jun , Cui Yong Zhu , Lv Li Hua , Min Byung Gil
Published: March 2013

In this study, kinetics and thermodynamics of sodium alginate/ hydroxyapatite composite adsorption fiber for adsorping Cd () were studied. The morphology and structure were characterized by SEM and IR, and the effects of pH value and bath ratio on Cd () adsorption were discussed. The model of adsorption kinetics and thermodynamics were simulated, and the parameters were calculated. The results showed that the sodium alginate/hydroxyapatite composite adsorption fiber possessed good adsorption ability towards Cd (). The optimum adsorption was found at the pH value of 6-7. High removal percent of more than 90% at low concentration and high concentration of Cd () was obtained at the bath ratio of 1:100 and 1:1000, respectively. The adsorption kinetics and thermodynamics studies showed that the pseudo-second-order model and Freundlich isotherm described the adsorption behaviors well. The thermodynamic parameters indicated that the adsorption of Cd () onto sodium alginate/hydroxyapatite composite adsorption fiber was physical and chemical sorption, endothermic in nature.
Effect of Sn Addition on the Corrosion Performance of Cast X-52 in H2S-Containing Environment at 60°C
Authors: Lin Hong Liang , Wang Jian Qiu , Han En-Hou
Published: March 2013

The electrochemical behavior of cast X-52 with different Sn content ranging from 0 to 1 wt. % was investigated using the methods of potentiodynamic test, electrochemical impedance spectroscopy (EIS). The immersion tests involved to examine the relationship between Sn addition and corrosion performance of cast X-52. In addition, the morphology and the compositions of surface corrosion products were analyzed using scanning electron microscope (SEM)/ energy dispersive spectroscopy (EDS). Potentiodynamic polarization curves showed that the presence of Sn decreased the corrosion current density. EIS indicated that Sn-containing steels had higher polarization resistances. These results confirmed that Sn played a positive role in reducing corrosion rate in H2S-containing environment. However, the corrosion resistance decreased with increasing Sn addition. It was proved that Sn improved the corrosion resistance with only a small content and large amount of Sn might lead to an advance of the pit due to occurrence of more acidification. Moreover, a continuous inner O-rich layer adherent to the matrix was found for Sn-addition samples, which lead to a decrease of corrosion rate due to its compact characteristic, compared with porous sulfide formed on the outer surface.
Enzymatic Degradation of the Copolyester P(BS-co-DGS)
Authors: Zhao Ying , Zhang Min , Shang Ming Ming , He Dan , Qiu Jian Hui
Published: March 2013

Lipase Novozym 435 was used as catalyst to degrade P(BS-co-DGS), which was a kind of PBS-based copolyester modified with diethylene glycol (DEG), in a THF/toluene mixed solvent system. P(BS-co-DGS) copolyesters were synthesized by copolymerization and characterized by 1H NMR. GPC and TGA were used to investigate average molecular weight and thermal property before and after degradation, respectively. After degraded by N435 for 30 h, the Mn of P(BS-co-DGS)10 (DEG content 10%) decreased from 8.33×104 to 3.52×104 g·mol-1 with some yellow oil droplets of oligomers appearing. And the initial decomposition temperature (the temperature at 5% mass loss) of P(BS-co-DGS)10 changed from 300.6 to 178.9. MALDI-TOF-MS results showed that none of DEG oligomers appeared in P(BS-co-DGS)10 degradation products. However, when the DEG content increased to 20%, there were the DEG circle oligomers as well as linear oligomers in the degradation products.
Fabrication and Thermoelectric Properties of Bi2Te3 Prepared by Combining Chemical Bath Method and Hot Pressing
Authors: Li Feng Yuan , Wang Yuan Yuan , Chen Song , Qin Zhen , Cai Ke Feng
Published: March 2013

Bi2Te3 bulk materials were prepared by combining chemical bath method and hot pressing at 80 MPa and 375 °C for 1 h. The samples before and after hot pressing were examined by X-ray diffraction, and the fracture surface of the bulk materials was observed by field emission scanning electron microscopy (FESEM). The electrical transport properties of the bulk materials were measured from room temperature up to 250 °C under Ar. The results indicate that sulfur addition can prevent the oxidation of Bi2Te3 nanostructures; however, it is not good to the thermoelectric properties of Bi2Te3 under the present synthesis conditions.
Physical Modification of Bentonite on the Salt Resistence Capacitiy
Authors: Sun Zhi Ming , Huai Yang Yang , Dou Zhong Lei , Zheng Shui Lin
Published: March 2013

A kind of bentonite composite with high salt resistance capacity was prepared using physical modification including physical mineral separation and doping porous non-metallic minerals. The results showed that through physical mineral separation, the content of montmorillonite and the salt resistance capacity increased substantially. The bentonite compsite sample doped by 5.0% diatomite showed better salt resistance capacity than the other compsite samples. The salt resistance mechanism was discussed through the double layer theory and physical and chemical properties of doped minerals.
Preparation of Modified Kaolin and its Properties of Water Retention
Authors: ZHANG Zengzhi , Qu Yong Ping
Published: March 2013

Kaolin was modified by propionamide in the present study. XRD analysis with X-ray diffractometer of Rigaku Corporation, infrared analysis with a Nicolet MagnaIR750 Fourier transform infrared (FTIR) spectroscope and the analysis of the TG and DTA curve with Composite Thermal Ana-lyzer were carried out. A Plant Growth Chamber was used to study the water-retaining property of modified kaolin. The results demonstrated that the microstructure of modified kaolin was flaky. Using the modified kaolin in arid regions the sub-surface moisture of soil can be maintained effectively, and the seedling survival rate increases obviously.
Adsorption of Aqueous Carbon Tetrachloride by a Novel TCAS-Loaded Resin
Authors: Peng Yong Biao , Hu Xiao Jun , Wu Hao , He Xin
Published: March 2013

Through the method of the static tests, the removal rate of aqueous carbon tetrachloride onto a new TCAS-loaded resin was researched. This TCAS-loaded resin was made of a novel supramolecular acceptor compound named thiacalix [arenetetrasulfonate (TCAS) and anion exchange resin, and the adsorption mechanism was discussed preliminarily. The results of adsorption indicated that the pH value was an important factor for the removal of carbon tetrachloride and it would be better for the adsorption if the pH value was greater than 6. The operating temperature should be controlled in 5 to 15°C for the adsorption of carbon tetrachloride onto TCAS-loaded resin while the removal rate decreased with the temperature increasing and the best time for reaction was 40min. The removal rate of carbon tetrachloride in aqueous solution was better when 25mL aqueous solution of carbon tetrachloride (1.0mg/L) was adsorbed by 0.5g TCAS-loaded resin. The carbon tetrachloride can be resolving and TCAS-loaded resin can be reused.
Study on the Adsorption Behavior of Acid Dyes on Collagen Fiber
Authors: Wang Xue Chuan , Bu Qiao Qiao , Qiang Tao Tao , Luo Min
Published: March 2013

The adsorption of acid black dye NT on collagen fiber (CF) was studied, and the effects of temperature, pH, initial dye concentration, adsorbent dosage and reaction time on the dye adsorption were tested, respectively. The results indicated that the optimal temperature and pH of acid black dye NT absorption were 40°C and 2.0, respectively. For a certain concentration of dyeing, the adsorption capacity decreased with the increasing of adsorbent dosage, but increased along with the extension of the contact time. In addition, the adsorption isotherms and kinetics of acid black dye NT on CF were investigated. By comparison, it was found that the Freundlich equation and Pseudosecond-order kinetic model can better describe the adsorption behavior of acidic black dye on CF. Thermodynamic parameters, such as G, H and S were determined to be-3.445 kJ/mol, 11.2 kJ/mol and 59.6 J/(mol·K), respectively. The results indicated that the adsorption was a spontaneous endothermic nature.
Preparation and Releasing Characteristics of Controlled Release Potassium Permanganate
Authors: Dong Shuang Shi , Wang Jin , Wang Yan Long , Zhang Jian Bin , Zhou Dan Dan , Shao Chun Yan
Published: March 2013

To extend the duration of KMnO4 in the groundwater in situ remediation, controlled release oxidant was prepared by dispersing the KMnO4 particles in the molten paraffin wax. Preparation conditions, including KMnO4 particles size, ultrasonic treatment time and the weight ratio of KMnO4 to wax (P/W) were optimized. The results showed that the average volume particle size of 13.20 μm and ultrasonic treatment of 10 min contribute to the most uniform dispersion of the KMnO4 particles in the molten paraffin wax. The scanning electron microscope (SEM) images showed that the increased amount of KMnO4 caused the crushed structure of paraffin wax, which resulted in the higher porosity of wax to contain more KMnO4. The KMnO4 loading amount increased significantly along with the increase of the P/W. However, the loading amount almost reached saturation by 609.63 mg/g when the P/W increased to 2/1. The releasing characteristics of the samples in the distilled water and the KMnO4 residual amount at different radial distance in the sample were examined by the bench scale tests. The releasing of KMnO4 could be divided into four periods and stable release took place after 40 d. Controlled release KMnO4 oxidant with P/W at 1/35 was used to remove COD in the leachate and 82.9% removal efficiency was obtained after 120 d treatment.
Preparation of Rubber Filler by Spent Activated Carbon
Authors: Wu Li Mei , Wang Xiao Yu , Liao Li Bing , Lv Guo Cheng
Published: March 2013

In this paper, the spent Activated Carbon (AC) which came from caramel plant was regenerated by the method of microorganism and chemistry. The optimal regeneration method was the combination of microorganism regeneration and NaOH regeneration. The optimal regeneration condition was treated by microorganism in 60 min at temperature of 35 °C and in NaOH (dosage was 6%). The optimal ultrafine grinding time was 5 h at 1200 rpm by adding 5 Triethanolamine, the effect of ultrafine grinding was better and the minimal size distribution was D90 3.82µm, D50 1.62 µm. the study ofAC surface modification was explored while combining the similar characteristics of AC and Carbon Black in its structure and composition. The possibility of reusing the spent AC was studied and the mechanical performance of rubber with modified AC was 43~44% higher than that of unmodified AC. The modified AC was characterized by Scanning electron microscope (SEM).
Synthesis and Electrochemical Performance of Graphite Oxide as Cathode Material for Rechargeable Batteries
Authors: Gao Ding Ding , Zhang Zhen
Published: March 2013

Graphite oxide (GO) is layered structure with functional groups such as hydroxyl, carboxyl and carbonyl between layers. Using GO as cathode active material allows lithium ions to enter the interior of cathode active material easily and the transformation of crystal form can also be obviated. GO has large amounts of surface area which enables cathode material to contact with liquid electrolyte directly, thereby direct and fast surface adsorption and reaction with lithium ions can be achieved. In this article, GO was prepared by modified Hummers method, characterized by XRD, IR, TG, and its electrochemical performance is studied as cathode active material. It is discovered that capacity can be dramatically improved and the cycle performance is excellent when GO is used as cathode material. The discharge capacity of first cycle can reach 480mAh/g at the current density 0.1A/g. The capacity is above 90% after 10 cycles.
Studies on the Microstructure of Pure and Doped Anatase TiO2 Nanoparticles by SAXS
Authors: Shi Wei Mei , Dai Xiao Jun , Yang Guang Cheng , Xu Yao , Liu Yi
Published: March 2013

Pure TiO2, Ce-doped and Ce/Si-codoped TiO2 nanoparticles with different Ce contents were synthesized by using a sol-gel-hydrothermal method. The as-synthesized samples were annealed at 400 °C. Their crystallization was investigated by Raman spectroscope. The result showed that Ce-doping and Ce-Si codoping decreased the crystallization. The interfacial and fractal properties were investigated by synchrotron radiation small angle X-ray scattering (SAXS). The results indicated that Ce-doping induced the Porod negative deviation, and the fractal properties showed TiO2 nanoparticles codoped by Ce-Si were rougher than these of the pure TiO2 and Ce-doped TiO2. This rough surface of the nanoparticles was helpful to improve the photocatalytic activity.
Photo Catalytic Properties of Fe-Modified and Magnetic Nanotitanium Prepared by Hydrothermal Method
Authors: Zhang Ya Ping , Zhi Qian Qian , Yu Lian Qing , Dong Kai Tuo , Liu Ri Shan , Yang Gui Yan
Published: March 2013

In order to improve the separation efficiency and the circular utilization ratio of the catalyst, the Fe-doped nanotitanium and nanotitanium supported on Fe2O3 carrier was prepared by hydrothermal method. The tetra-butyl titanate and ethanol were used as starting materials to prepare nanotitanium. The results of Fe-doped nanotitanium showed that the doping of iron changed the nanotitanium crystal and crystal morphology. No matter UV-light or mercury lamp 577 nm irradiation, the samples with 0.5 mM Fe addition showed the highest photo catalytic activity, with degradation rate of methyl blue above 95%. The structure, photo catalytic activity and magnetic properties analysis showed that the magnetic nanotitanium met the purpose of separation between the catalyst and reaction solution. The photo catalytic activity of nanotitanium supported on Fe2O3 carrier has respond to visible light. With mercury lamp 577 nm as irradiation source, degradation rate of methylene blue light could reach 63.40%.
Activation Energy Measurement of Cu/SS-AlN/SiAlOx Solar Selective Absorbing Coating
Authors: Wang Jin Ping , Yuan Bo , Wang Jian , Luo Yi
Published: March 2013

Activation energy is an important parameter which determines thermal stability of solar selective absorbing coating. In this investigation, a new performance criterion (PC) was defined for solar selective coating according to our modified equation of photo-thermal conversion. Then the activation energy of Cu/stainless steel (SS)-AlN/SiAlOx solar selective absorbing coating was measured. Cu/SS-AlN/SiAlOx tandem films were deposited by magnetron sputtering. Accelerated ageing tests were performed on the coating at 500°C and 550°C, under the atmosphere, calculating PC from the reflectance spectrum and measuring the failure time. According to Arrhenius equation, the activation energy and the equivalent life span of Cu/SS-AlN/SiAlOx tandem film at 400°C were determined to be about 187.4kJ/mol and more than 16260 hours, respectively.
Thermal Optimization of Exhaust-Based Thermoelectric Generator
Authors: Deng Ya Dong , Chen Shan , Liu Xun
Published: March 2013

The potential for automotive exhaust heat based thermoelectric generator (TEG) has been increased with continuously advances in thermoelectric technology. The thermal performance of the heat exchanger in exhaust-based TEG was analyzed. In terms of interface temperature and thermal uniformity, the thermal characteristics of the heat exchangers with different internal structures, materials and thicknesses were discussed. CFD simulations and infrared experiments on a high-performance production engine with a dynamometer were carried out. It was proved that the plate-shape heat exchanger made of brass with internal baffles and the thickness of 3mm, obtained a relatively optimal thermal performance, and it will help to improve the thermal performance of the TEG.
Influence Factors on the Size of Spherical Silver Powder Used for Solar Cell Top Electrode Paste
Authors: Zhang Si , Zhu Yue Lin , Song Jia
Published: March 2013

The ultra-fine silver powders were prepared by chemical reduction using nitric acid silver (AgNO3) as raw material, ascorbic acid (C6H8O6) as deoxidizer and adding polyvinylpyrrolidone (PVP) as dispersing agent. The influence factors, such as AgNO3 solution concentration, ascorbic acid solution concentration, PVP dosage and reaction conditions such as temperature, PH etc. were studied. The morphology and particle size distribution were observed by Field Emission Scanning Electron Microscopy (FSEM) and laser particle analyzer. The composition was analyzed by Energy Dispersive Spectrometer (EDS).The crystal phase was tested by X-ray Diffraction (XRD). It indicates that the spherical ultra-fine silver powder is face-centered cubic structure, its diameter is about 1.0 μm with homogeneous particle size distribution and smooth surface. It was prepared under the conditions as following: dropwise added 60 g/L AgNO3 solution into 40g/L ascorbic acid solution, with the presence of PVP, and pH=3,45,360rpm. It meets the requirements of paste for solar cells top electrode.
Structure Characterisation and Optical Properties of Eu3+-Doped LaAlO3
Authors: Wu Gang , Deng Hong Mei , Ding Nuo Fan , Yan Hu Rui , Yang Ping Xiong , Chu Jun Hao
Published: March 2013

In this paper, Eu3+-doped LaAlO3 powders which with the concentration of Eu3+ in the range of 0~5% were prepared by a new liquid mixing method. The structure of the LaAlO3 powders were investigated by X-ray diffraction (XRD), and the influence of the increase of temperature on the crystal structure were also studied. We found that the powders crystallized above 800 which means higher temperature can improve the crystallization. The influences of the increasing Eu3+ concentration were also studied through the XRD patterns. The average sizes of the samples were also calculated by the Sherrer equation. The optical properties of different concentration of Eu3+-doped LaAlO3 particles were investigated through the reflection spectra.
Microstructure and Mechanical Properties of a Multi-Modal Al Alloy with High Strength
Authors: Hao Xiao Ning , Zheng Rui Xiao , Hao Li Rong , Yang Han , Ma Chao Li
Published: March 2013

Nanocrystalline (NC) Al alloy powder was fabricated by milling 2024 Al alloy powder and Fe-based metallic glass (FMG) particles. The NC Al alloy powder was consolidated into bulk sample by adding a part of atomized coarse-grained (CG) 2024 alloy powder. The microstructure and mechanical properties of powder and consolidated bulk materials were examined by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and mechanical test. It revealed that the FMG particles were uniformly distributed in the NC aluminum alloy powder. In the consolidation process, the grain size increased, and Al2CuMg phase precipitated. The multi-modal Al alloy by consolidation of FMG particles, NC and CG powder, exhibited higher yield strength up to 517 MPa and better plasticity in comparison to the samples without CG powder.
Atomistic Simulation Study on the Tensile Deformation Behaviour of Nanocrystalline Ni
Authors: Li Wen Bin , Yuan Fu Ping , Wu Xiao Lei
Published: March 2013

Using molecular dynamics simulations, the influence of transverse tensile stresses on the plastic deformation behaviour of nanocrystalline (NC) Ni under tension has been investigated. The sample with an average grain size of 20 nm was created using a Voronoi construction, and two different tensile tests of the sample were performed at a constant strain rate. The simulation results revealed that more partials were emitted from the grain boundaries and propagate into the grain interiors after adding the transverse tensile stress, enhancing the dislocation density in the grain interiors. This increased dislocation density can cause additional strain hardening observed in the stress strain curve. Meanwhile, it was observed from microstructures that nanovoids are easier to form and coalesce into cracks under the biaxial stress state, causing strain softening. The two competing effects of the transverse tensile stress on the plastic deformation behaviour of NC Ni resulted in the flow stresses from 4% to 10% strain in the biaxial stress state slightly larger than those in the uniaxial stress state.
A Strengthening Model of Cu-Cr In Situ Fibrous Composites Produced by Equal Channel Angular Pressing
Authors: Wei Wei , Wei Kun Xia , Alexandrov Igor V. , Wang Fei , Hu Jing
Published: March 2013

The composite filament structure was produced in the Cu-5.7%Cr and Cu-12.4%Cr as-cast alloy ingots by using equal channel angular pressing (ECAP) at room temperature. Optical and TEM microstructure, micro-hardness, tensile strength and electrical conductivity of ECAPed samples were investigated. The rotation and spreading of Cr particles took place during ECAP, and resulted in long thin in-situ filaments. The tensile strength increased with the number of the ECAP passes. A strengthening model was recommended to predict the enhancement of the tensile strength in Cu-Cr in situ fibrous composites.