bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Group Piles Effects of Offshore Engineering under Lateral Load
Authors: Di Sheng Jie , Wang Ming Yuan , Du Wen Bo
Published: April 2014

The mechanical behavior of group piles under lateral load is a very complex process of pile-soil interaction. Due to the group effect, the lateral capacity of individual piles can not be fully developed. Deduction factors are applied to the lateral soil reaction, and then lateral analysis is performed for individual piles. After p-y curve for each pile is constructed, the soil pressure of group piles is the sum of soil pressure of single pile at the same deflection under one pile cap. The mechanical different behaviors of the front piles and the back piles are analyzed and compared based on a practical engineering.
Model Tests on Additional Stress Transmission between Different Granular Materials in Foundation Soils
Authors: Wang Chang Dan , Zhou Shun Hua , Su Hui
Published: April 2014

To research and analyze the additional stress distribution and change of granular materials, the model tests are used to observe vertical additional stress in different position and depth in different foundations. And the comparison between observed values both in different soils and single soils is conducted to analyze the transmission and attenuation of additional stress in granular materials. The research results show that the existing of boundary surface can lead to different vertical additional stress transmit obviously. And with the increasing of loading, the vertical additional stress differences between that of different soils get larger, meanwhile, the ratio of stress differences to smaller additional stress increases slightly. With the increasing of depth, the attenuation rate of vertical additional stress of silty soil changes much fast than that of fine sand. Wherever in horizontal direction or vertical direction, the vertical additional stress of fine sand which has higher compression modulus in different soils is slightly larger than that in single soil and transfers additional stress (loading) more under the same loading. To granular materials, inner friction structure effect is evident influence to additional stress transfer.
Effect Analysis on Tunnel Serviceability State by the above Expressway Extension in Loess Area
Authors: Sun Ke Guo , Kong Chao , Qiu Wen Ge , Liu Kai , Xu Wei Ping , Gong Lun
Published: April 2014

Based on the typical adjacent project of extension of LianHuo expressway which is constructed on WenXiang tunnel, the finite difference software, Flac3D, is adopted to stimulate the process of the construction. In this paper, from two aspects, the deformation of profile and cross-section, serviceability state is analyzed in detail. In the profile plot, usually displacement of the invert arch is less than that of the vault, and affected by the mutual position of topography and excavation, the maximum displacement, 6.3mm, merges at 50m of the vault in the profile plot; in the cross-section plot, due to occurrence of unloading effect brought by overlying excavation, tunnel structure has the tendency of rising toward the excavation. The calculated result shows that the displacement of WenXiang tunnel locating on the line of ZhengZhou-Xi’an Railway High-speed can be well controlled by adopting the excavation method of layering excavation at vertical direction and section excavation at longitudinal direction, which makes the safety of serviceability state of extension of expressway and the operation of Railway High-speed.
Key Technology for the Structure Design of Mining Metro Station in Rock Strata
Authors: Wang Jun
Published: April 2014

Focused on the mining method, the parameters of primary support, and the design method for the interface of metro station and air duct structure, what are encountered during the design of mining station in rock strata. Through the combination of numerical method and theoretical analysis, and the comparison with field measured data, we know that double-side-wall heading method is safe and feasible, design method based on plastic stage can be used for the checking of primary support structure, and the combination of support in advance and closed steel frame can insure the safety of the interface of metro station and air duct structure. Through analysis, the changes of displacement and stress are focused around vault and arch springer, and the decrease and increase of safety factor during construction are also made clear. The study can offer a reference for the similar project in the future.
Mechanism Analysis of Hydraulic Cutting Outburst Prevention Measure Applied to Mining Area of Heilongjiang Province
Authors: Liu Xi Ming , Liu Min Hui , Kang Yu , Zhou Jing
Published: April 2014

Grave protrusion coal seam tunnelling hydraulic cutting outburst prevention measure is a new technology in the world. The measure had been applied successfully to Jiaozuo Coal Group and run well. The mining areas of Heilongjiang are characterized by complex geological structures, more medium-thickness protrusion coal seam and abundant groundwater, on the basis of referring to technical parameters of the outburst prevention measures of Jiaozuo Coal Group, the outburst prevention mechanism of hydraulic cutting applied to medium-thickness protrusion coal seam was analyzed from the coal stress surrounding hole, internal forces of gas, stress concentrated zone and its moving speed, thickness of pressure released zone and intensity change of coal, and the feasibility of hydraulic cutting outburst prevention technique applied to Heilongjiang was verified. This provides theoretical basis for the technique applied to mining area of Heilongjiang Province.
Research of Train Wind Characteristics in High-Speed Railway Tunnel
Authors: Fei Rui Zhen , Peng Li Min , Yang Wei Chao , Yan Wei Guang
Published: April 2014

According to the 100㎡ high-speed tunnel cross-section which is generally used in high-speed railway of China, this paper develops a tunnel-air-train simulation model, based on the three-dimensional incompressible Navier-Stokes equations and the standard k-e turbulence model. Time-history variation rules and space distribution characteristics of train wind are studied respectively. The results show that: train wind is complex three-dimensional flow changing with time and space, air at the front of train flows away from the train head, while air at the rear of train flows to the train tail.
Research on Influence of Span on Surrounding Rock Quality of Tunnels
Authors: Geng Xiao Jie , Du Xiao Wei , Yan Qiong
Published: April 2014

The influence of tunnel’s span on rock mass quality is getting more and more recognition along with increasing large span tunnels’ construction. As national standard of China, BQ qualification is generally applied. Based on the measured data and numerical experiment, the relationship between surrounding rock displacement and quality evaluation is studied, and span effect correction factor is established. The modified rock quality index can provide the basis of guiding the design and construction of tunnels.
Stress Management in Rock Drivage Team Based on Fault Tree Analysis Method
Authors: Shan Ren Liang , Dong Shao Hua , Huang Bao Long , Huang Fei , Wu Shu Jing , Wu Qing Ao
Published: April 2014

In order to achieve effective stress management in rock drivage team, this paper use fault tree analysis method to build fault tree model for the stress management of rock borehole-blasting drivage team. Under this model, the stressor of rock drivage team is identified, the logical relationship between the stressor and work of errors in rock drivage team is analyzed, the corresponding recommendations for the stress management of coal companies are provided.
Study on Model of Back-Filled Grouting of Shield Tunnel
Authors: Wang Dao Yuan , Li Dong , Yuan Jin Xiu
Published: April 2014

Basing on the theory of maag cylindrical diffusion, back grout diffusion radius and grouting pressure formula of shield tunnel were derived in two cases of the viscosity time-dependent behavior or not.The distribution law of diffusion radius and the pressure to segments were obtained by applicating the spreading model in some project.The results show that grout diffusion radius and grouting pressure both increase with the increasing of grouting time and grouting pressure whether considering the viscosity time-dependent behavior or not.In the same grouting time (pressure),the calculated values that unconsidering the viscosity time-dependent behavior are bigger than the values of considering.
The Operation Safety Evaluation of Xi'an Subway
Authors: He Yan Fang , Ji Chang Xu
Published: April 2014

Line 2 of Xi’an subway is the earliest subway in Shaanxi , its safety has not been fully and thoroughly checked because of the perfect record of non-fault during its operation. In this paper, facility, management and fault indexes are set up, and the and indexes are also built through the organization and responsibility analysis of subsystem so as to safety assessment index system. Finally, AHP and fuzzy evaluation method are used to evaluate the subway operation results and propose appropriate corrective measures.
Safety Assessment of Secondary Lining on the Basis of Load Structure Method and Strength Reduction Method
Authors: Liu Kai , Wang Gang , Kong Chao
Published: April 2014

So far, due to the complexity of underground engineering, a mature and proper method used to determine rock pressure is not for sure. For now, method to design lining structure mainly adopts empirical design, assisted by load structure method. The paper assesses the safety of lining structure from two aspects, that is, from load structure method and from strength reduction method. The results indicate that compared with strength reduction method to evaluate safety of the lining structure, load structure method is relatively conservative.
Dynamic Response Analysis of Soil Slope under Strong Earthquake
Authors: Huang Shuai , Yan Hong Ye , Cai De Gou , Song Bo
Published: April 2014

Based on the finite element model of slope, the stability and dynamic response of sand slope are studied. The results show that with the increase of groundwater, the maximum horizontal displacement of slope shows increasing trend, and reach maximum horizontal displacement on the top of the slope, and the displacement under near-field earthquake is greater than that under far-field earthquake. The accelerations with groundwater are less than that without groundwater, which shows that the existence of groundwater damps vibration. Without considering the groundwater, the destruction of slope is mainly the circular shearing damage through the slope toe, while the destruction is not yet through the slope toe, but from a point on the front of slope.
Finite Element Analysis on Low Cycle Fatigue Properties of HRBF RC Pile Tip
Authors: Fu Qian , Liang Shu Ting , Zhu Xiao Jun
Published: April 2014

Numerical simulation of the entire process of HRBF RC pile tip under the low cycle fatigue tests were carried out by nonlinear finite element software ABAQUS. The simulation results included hysteretic curve, skeleton curve, the equivalent plastic strain cloud, the concrete damage cloud and etc. On this basis, it is simulated and calculated by changing the strength of concrete, reinforment ratio, axial load ratio, strength of longitudinal reinforcement and stirrup ratio, to gain the effect of skeleton curve. FEA results show that: the results wear agreed well with the experimental results, and this method was proved feasible; high-strength steel could improve the bearing capacity of components, and its members had good energy dissipation capacity.
Seismic Performance Evaluation of Residential Structures in Egypt
Authors: Ibrahim Yasser E. , Shallan Osman , Elshihy Ashraf , Selim Mohamed
Published: April 2014

In this research, analytical fragility curves for three existing structures are presented. Structures are 2-story, 6-story and 10-story residential reinforced concrete structures designed under dead ,live and seismic loads of zone 3 according to Egyptian code (2008). The design acceleration is 0.15g. The fragility curves are developed based on nonlinear incremental dynamic analysis of three dimensional structural models using SeismoStruct under twelve historic ground motions. Four performance levels are considered; fully operational, operational, life safe and near collapse.
Seismic Performance of T-Shaped CFT Column to Steel Frame Beam Connection – Experimental Study
Authors: Li Yan Tao , Xu Cheng Xiang , Du Guo Feng
Published: April 2014

The focus of this research program is T-shaped CFT central column to steel frame beam connection. 3 joints with strong columns-weak beams and 1 joint with strong beams-weak columns 1:2 scale specimens were tested under constant axial loads and cyclic horizontal loads. Overall impact of axial force ratio and beam to column linear stiffness ratio on joint failure mechanism, hysteretic behavior, deformation ductility, and energy dissipation capability was investigated. Results showed that the failure mechanism for specimens with strong columns-weak beams was local buckling of the steel beam flanges and formation of the plastic hinges. There was minimum damage on the concrete column and joint panel zone. For a specimen with strong beams-weak columns, there was local buckling fracture on steel tube above and below the joint panel zone. Crushing of the core concrete was also observed with formation of the column hinges. It was found that both axial forces and beam to column linear stiffness ratio had impacts on joint capacity and ductility behavior of the specimens. Experiment results showed that the joint models had deformation ductility factor between 3.39 and 3.91 and viscous damping ratio between 0.46 and 0.51.
Shaking Table Test of Underground Pipeline under Three Dimension Seismic Excitation – Numerical Simulation
Authors: Fu Xiao , Bi Jun Wei , Wang Zhi Jia , Yang Chang Wei
Published: April 2014

Based on the design of the large-scale shaking table test of an underground pipeline under three dimension seismic excitation, the dynamic response of the soil-structure is analyzed by using ANSYS. In the numerical simulation, Drucker-Prager constitutive model is adopted to simulate the soil, the interface between soil and pipeline are simulated with zero thickness contact elements, size effects of test box are diminished by defining viscoelastic boundary around soil, the acceleration time history curve of the original earthquake wave is compressed and processed according to using the model scale similarity and energy duration which is presented by Trifunac-Brady [1] , and then the characteristic of seismic response of the pipeline can be found. The results show that the top of pipeline is the seismic response intense regional, deformation displacements of the central areas at the bottom and top of pipeline are always larger than others, the entrance and exit are the weak positions of anti-seismic structure; moreover, the dynamic response and interactions of soil-pipeline in the model experiment can be more accurately simulated by the methods presented in the paper. Thus, it can be served as reference for the design and construction of subsurface structures.
Study on Corrugated Steel Web Bridge Seismic Isolation Technology in High Intensity Seismic Region
Authors: Li Hong Xue , Zhao Yong Ming
Published: April 2014

The rapid development of modern seismic isolation technology has opened up new avenues of bridge seismic. For the bridge structure in highly seismic region,seismic isolation devices reduce the effects of the earthquake damage to bridges, but also reduce the ability of the bridge structure to resist other loads along with the increase of the displacement under seismic action. Nowadays, there are few engineering examples of the composite bridge with corrugated steel webs using seismic isolation technology. In this paper, we use Bridge Xiaoshagou as an example to study isolation technology with nonlinear time history analysis.
The Seismic Performance Analysis for the Ceramsite Concrete Frame – Shear Wall Structure
Authors: Chen Jin Xuan , Liu Yan Wei , Yang Ju Rui , Hou Xiao Xia
Published: April 2014

The paper focused on the seismic performance of ceramsite concrete frame—shear wall, which conducted the modal analysis and elasto-plastic time history analysis for 6 layers ceramsite concrete frame—shear wall and ordinary concrete frame—shear wall by software SAP2000. Then compared the results, which showed that the periods of ceramsite concrete frame—shear wall structure was longer than the ordinary concrete frame—shear wall structure, while the inter-storey drift ratio and the maximum absolute acceleration are less than ordinary concrete frame—shear wall. Besides, the largest base shear of ceramsite concrete frame—shear wall structure was less than ordinary concrete frame—shear wall structure. And the seismic performance of ceramsite concrete frame—shear wall showed was better than ordinary concrete frame—shear wall structure.
Chemical Grouting Method and its Effectiveness for Protection of Autoclaved Aerated Concrete Masonry
Authors: Struhárová Alena
Published: April 2014

Protection of masonry and constructions of buildings against water and moisture is an important part of building industry. Contribution deals with problems of moisture, its classification and moisture level on the constructions. The chemical grouting method for protection of autoclaved aerated concrete masonry against capillary moisture via treatment by using the hydrophobic grouting solution Freezteq DPC System is described in this contribution.
Geocement-Based Coatings for Repair and Protection of Concrete Subjected to Exposure to Ammonium Sulfate
Authors: Kryvenko Pavlo V. , Guziy Sergii G. , Kyrychok Vladimir Ivanovich
Published: April 2014

The geocement-based coatings for repair and protection of concrete structures of which the installations for production of biogas, water supply and sewage water disposal pipelines are made have been developed and have been tried in practice. Resistance of the developed coatings in an aggressive environment (5 % solution of ammonium sulfate) as well as basic physico- chemical processes taking place during interaction of the ammonium salts with the geocements have been studied and the results are discussed. A conclusion was made that among other geocement hydration products which can resist attacks of sulfate-ammonium ions, faujasite, chabazite and mordenite had the highest resistance, whereas heulandite and hydrosodalite have the lowest resistance. This assumption is in agreement with the outcomes of other researchers. The results of examination show that the ammonium-containing zeolites have been synthesized within the hydration products, these were: ammonium analcime, (NH4, Na)-zeolite-E, zeolite a, zeolite ZK-21 and NH4-zeolite-W. The coated concrete (a geocement (Na2O×Al2O3×6SiO2×30 H2O)-based coating)) is found to be corrosion resistant in aggressive environment containing ammonium sulfates: its coefficient of resistance is 1.01, being at an age of 30 days by 1.2 times higher compared to that of the uncoated concrete of the same age.
Production Possibilities of Concrete Based on Artificial Fly Ash Aggregates
Authors: Černý Vit , Sokol Pavel , Drochytka Rostislav
Published: April 2014

Production of artificial aggregates is one of the suitable ways how to use the maximum ratio of fly ash in construction materials. Subsequent use of aggregates is directed in addition to various embankments, filter layers and also for lightweight concrete. Concrete can be used wherever required low weight while maintaining the necessary strength. The contribution is geared to verify the applicability of newly produced artificial aggregates from different types of fly ash for standard concrete.
Shrinkage-Compensating Alkali Activated Slag Cement Mortars for Crack Repair and Joint Grouting in Concretes
Authors: Kryvenko Pavlo V. , Vozniuk Grygorii Viktorovich , Goncharova Anastasia Maksimovna , Kavalerova Elena Sergeevna
Published: April 2014

Physico-chemical processes of hardening of a cement stone are accompanied with shrinkage is known to result in crack formation, loss of concrete structure integrity and finally, to shorter service life. These drawbacks make problems in using traditional portland cement based mortars for joint grouting and crack repair in concretes. Known-in-the-art solutions based on calcium aluminate cements are also not efficient due to high cost and instability of cement stone hydration products over time in various service conditions. Shrinkage-compensating alkali activated slag cement mortars are proposed to solve the problems connected with crack repair and joint grouting. They are simple in preparation and application and have a set of high physico-mechanical properties, excellent durability and reasonable cost.
Surface Modification of Fresh Placed Concrete and its Durability at Effect of Defrosting Substances
Authors: Urban Jaroslav , Klečka Tomáš
Published: April 2014

In the Czech Republic, the deicing salt resistance is determined through the scaling from the sample exposed to 3% NaCl solution after prescribed numbers of frosting-defrosting cycles (see ČSN 731326). The surface layer of concrete is contacted as the first with aggressive substances and is an entrance gate for unwanted ones. Its quality is not only affected by the proposed mix and procedure of placing fresh concrete with following curing, but also by the final modification performed with various types of smoothers.
Bacterial Deteriorations of Wooden Pile Foundations due to Permanent Soil and Water Contact
Authors: Haroske Gesa , Diederichs Ulrich , Petranek Vít
Published: April 2014

Many structures resting on pile foundations, which are surrounded by water in the soil for decades or centuries. In the context of status explorations or assessments questions arise concerning their conservation status and their durability. The paper presents the results of extensive in situ studies and laboratory tests, which were performed on older wooden pile foundations of port facilities, bridges and building foundations in the framework of planning of maintenance measures. In the focus of this work are studies on the biotic attack to the woods and its effect on the density and strength characteristics of the piles.
Inter alia, the investigations have revealed that the wood under the said anaerobic conditions suffers deterioration due to bacterial attack, rarely by higher fungi. As discovered by microscopic investigations on thin sections, the bacterial attack appears as a partial degradation in the individual wood cells, especially in the middle lamella of the late wood cells and the dots. As indicated by the results of the of the density and strength test results, the bacterial attack is - compared to fungal attack - a very slow but steady process. It causes also strength reduction of the woods and losses of the load bearing capacity of the structures, and has to be taken into account in the static assessments.
The Existing Timber Structures – Possibilities and Limits of Diagnostic Methods in Assessment Process
Authors: Daňková Jana , Murínová Tereza , Mec Pavel
Published: April 2014

The wood is traditionally been applied as the building material in building and bridge construction. The number of applications of wood in building structures increases in recent years. According with this trend, the emphasis is on the development of diagnostic and monitoring methods for existing wood structures. In the paper, published results of a survey of existing wood structures in relation to the evaluation of qualitative and quantitative characteristics of the investigated structures. There are finally discussed the possibility to reproduce the results of non-destructive measurement relative to evaluate the strength characteristics of wood.
Verification of Range of Chemical Grouting of Masonry by Non-Destructive Method Using Infrared Thermography
Authors: Peřina Zdeněk , Plšek Boris , Wolfová Marie
Published: April 2014

Verification of reach of grouting masonry using infrared thermography. Chemical grouting masonry is a progressive, modern restoration technique. Verification of reach (efficiency) of injection media by nondestructive methods have not been established and verified, yet. The article deals with the presentation of the results of the pilot thermography measurements.
Evaluation of Compressive Strength of Historic Masonry Using Measurements
Authors: Sýkora Miroslav , Holicky Milan
Published: April 2014

Historic structures are made of different types of masonry with significantly different properties. As a rule the information on mechanical properties of masonry components has to be obtained by testing. Estimation of masonry strength from measurements with due regard to relevant uncertainties may be a key issue of the reliability assessment. The probabilistic model of masonry strength is developed considering uncertainties in basic variables and testing procedures. It appears that the characteristics of masonry strength can be well estimated using fundamental statistical methods.
Experimental Investigation of Transparent Glazed Noise Reducing Traffic Barrier against Impact of Flying Stones
Authors: Bouška Petr , Špaček Miroslav , Vokáč Miroslav , Eliášová Martina , Bittner Tomáš
Published: April 2014

Number of experimental tests was carried out to simulate a flying stone at road noise barriers under laboratory conditions in the Klokner Institute laboratory. Prefabricated modules made in the Czech Republic were used for these experiments. It was designed testing system consisting of a toughened steel pin, the guiding device and the supporting scaffolding. This system allows to simulate the impact of the steel hammer with kinetic energy of 30 Nm in accordance with the requirements of the standard ČSN EN 1974-1 [.
Usage of Distributed Fiber Optical Temperature Sensors during Building Redevelopment
Authors: Vašínek Vladimír , Šmíra Pavel , Rasnerova Vladimira , Nasswettrová Andrea , Jaros Jakub , Liner Andrej , Papes Martin
Published: April 2014

This contribution describes the novel unique technology with the usage of fiber optical sensors with temperature resolution up to 0.01°C and spatial resolution 1m. This technology is supplemented with fiber optical strain sensor with pressure resolution 1Pa. Fiber optical sensors are based on nonlinear effects within the optical fibers, they behave as distributed sensors making possible to measure temperature and strain with one fiber in many points contemporarily during building redevelopments. For temperature measurements Raman scattering within multimode optical fiber is used. Results from real redevelopments are presented.
Determination of Effects of UV Radiation on Remedial Plasters
Authors: Fořtová Kristina , Balík Lukáš , Burgetová Eva
Published: April 2014

The paper deals with the influence of climatic factors on selected properties of remedial plaster. The results of experimental measurements of hydrophobicity on samples of plasters after exposure to UV radiation are analyzed.
The Application of Nanomaterials in Restoring Historic Structures
Authors: Kroftová Klára
Published: April 2014

The current approach to the restoration of listed buildings emphasizes the minimization of interference and the maintenance of authenticity and historical value as a whole, alongside detail. This opens a wide field of applications for composite materials and nanomaterials. The use of nanotechnology is currently one of the most reviewed areas of research in various technical disciplines. The extraordinary properties of nanomaterials allow their successful use in the restoration of listed buildings.
Determination of Selected Mechanical and Physical Properties of Historic Full Burnt Bricks in Frame of Project of Monitoring their Diffusion Properties
Authors: Nenadálová Šárka , Balík Lukáš , Kolisko Jiří
Published: April 2014

How perhaps everybody from us must notice the degradation of buildings is omnipresent and it doesnt avoid even historic buildings that many times belong to our national heritage. Most of historic buildings were built from the most common material of that time, i.e. from full burnt bricks. But these bricks werent as similar as eggs are each other how it is ordinary for materials at these days. Within our research project the tests that determine the ranges of properties of the historic bricks were performed. The tests of mechanical properties and particularly damp tests were performed. The goal of our research was also the comparison of surface finishing of full burnt bricks from the point of view of diffusion transport of moisture. This paper summarizes valuable results that show what range of properties of historic bricks we can expect and how we should behave towards these old buildings in our best.
Microwave-Assisted Preparation of Nitrogen Doped Nano-TiO2 and the Study on the Properties
Authors: Zhou Da Huan , Chen Xu , Li Fu Yun , Guo Lan Ying , Yang Li Zhen
Published: April 2014

The nitrogen doped nanoTiO2 was prepared by the microwave-assisted method. The properties were characterized by the X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The effects of the calcination temperature and the doping amount of nitrogen on the nitrogen doped nanoTiO2 crystal phase and its photocatalytic properties were studied. The result indicated that with the increase of the calcination temperature, the proportion of rutile in the mixed crystal phases increased gradually. When the calcination temperature was 650°C, the pure rutile phase appeared. When the TiO2 was calcinated at 400 °C, the particle size was the minimum (17nm). This mixed crystal was conducive to the good photocatalytic properties of nanoTiO2. The degradation rate of methyl orange was 50.86%. At the calcination temperature of 450 °C, the proportion of rutile in the mixed crystal phase increased first and then decreased, until finally it increased again with the increase of the doping amount of nitrogen. When the ratio of nitrogen to titanium was 1:0.5, the catalytic effect was the best. The photocatalytic degradation efficiency was 71.63%, and the particle size was also approximately the minimum (15nm).
Spin Reorientation Transition and Magnetization Reversal Mechanism of Gd Doped FeCo High-Frequency Soft Magnetic Thin Films
Authors: An Yu Rong , Li Yue , Wang Zhen , Zuo Ya Lu , Xi Li
Published: April 2014

The magnetic FeCoGd thin films with various sputtering power from 10 to 30 W were fabricated on glass substrates by magnetron co-sputtering. The crystal structure of as-deposited FeCoGd thin films was investigated by X-ray diffraction. And an increasing trend of grain size with the increasing sputtering power was shown. When sputtering power is below 30 W, the films exhibited obviously in-plane uniaxial magnetic anisotropy, and the in-plane magnetic anisotropy field Hkdecreased with increasing deposition power. Moreover, good high frequency characteristics were obtained. The magnetization reversal mechanism has been investigated via the in-plane angular dependences of the magnetization and the coercivity. The experimental data points indicated that the magnetization reversal mechanism of FeCoGd film with in-plane uniaxial anisotropy is domain-wall depinning and coherent rotation when the applied field is close to the easy axis and hard axis, respectively. A spin reorientation transition phenomenon was observed when deposition power is larger than 30 W. A stripe domain structure for the sample with 30 W deposition power was developed due to a dominated perpendicular magnetic anisotropy.
Optical Properties of Silica Colloids Suspensions in Electric Field
Authors: Luo Yu Xia , Zhang Jian Fei , Sun Ai Hua , Chu Cheng Yi , Zhou Shi , Guo Jian Jun , Xu Gao Jie
Published: April 2014

We studied the optical properties of silica colloids suspensions made of nanospheres having an average diameter of 50, 90, 120, and 300 nm in electric field. It was illustrated that a colloidal suspension with a particle size of 120 nm shows a dramatic change of the reflection peak position in response to the applied potential. With the increase of the concentration, the position of peak maximum slightly blue-shifted and the reflection intensity slightly increased. The impact of solvents on optical properties of silica colloids suspensions was studied. It was demonstrated that the position of peak maximum has a dramatic change only in propylene carbonate; there were no marked changes in ethylene glycol and water. The intensity of reflection peak was strongest in water. We analyze the mechanism and attribute this phenomenon to the hydrogen-bonding ability of the solvents.
Rheological and Interfacial Property of Nano-Al with HTPB, GAP and PET
Authors: Xu Hui Xiang , Zhou Wen Jing , Zhao Feng Qi , Pang Wei Qiang , Sun Zhi Hua , Xu Si Yu , Wang Guo Qiang
Published: April 2014

Rheological and interfacial property of nanoAl with Hydroxyl-terminated polybutadiene (HTPB), glycidyl azide polymer (GAP) and poly (ethyleneoxide-co-tetrafuran)(PET) were investigated by means of RS-300 rheometer, DCAT21 dynamic contact angle measuring instrument, interface surface tension meter (Germany) and X-ray photoelectron spectroscopy (xps). Rheological properties of three binders and nanoAl/binder suspensions in the mixing ratio of 1:2 were discussed. Results show that Three kinds of binders exhibit pseudoplastic characteristics with the apparent viscosity of less than 3 Pa s,and have weak interaction between molecular chain segment of itself. Within 30~60°C, with temperature increasing, the apparent viscosity of nanoAl suspensions decreases, in which the nanoAl/HTPB and nanoAl/GAP belong to pseudoplastic fluid of sensitive to temperature, with flow activation energy of 38.05 kJ/mol and 52.07 kJ /mol, respectively, but nanoAl/PET belongs to a bingham fluid of sensitive to changes in the shear rate, with flow activation energy of only 1.506 kJ/mol. The contact angles of nanoAl,GAP,HTPB and PET were measured by means of dynamic contact angle/surface tension instrument. The calculated values of adhesion and spread coefficient of nanoAl with binders decrease in the order Wnano-Al/PET>Wnano-Al/GAP>Wnano-Al/HTPB and Snano-Al/PET>Snano-Al/GAP>Snano-Al/HTPB.The results indicate that the interactions of nanoAl with binders decrease in the order nanoAl/PET>nanoAl/GAP>nanoAl/HTPB,which is consistent with the trends of apparent viscosity of the suspensions . Binding energy of Oxygen in nanoAl/HTPB is 532.03 ev,which is bigger than that of nanoAl,and indicate a strong action between nanoAl and HTPB.
The Surface Passivation on the Optical and Surface Properties of InP
Authors: Gao Xian , Wei Zhi Peng , Fang Dan , Zhao Hai Feng , Fang Xuan , Tian Shan Shan , Tang Ji Long , Du Peng , Chu Xue Ying , Li Jin Hua , Fang Fang , Wang Xiao Hua
Published: April 2014

We propose a novel surface passivation of InP, to obtain the strong luminescence property and completely remove the surface state. InP is passivated by (NH4)2S solution, then treated by rapid thermal annealing (RTA) at different temperatures. Compared with unannealing sample, the PL intensity is increased to 1.7 times. We adopt atomic layer deposition (ALD) of Al2O3 avoiding oxidizing gradually.
Quasi-Classical Trajectory Study of the Scalar Properties of the Reaction N(4S)+H2(v=0,1,2,3; j=0)→NH+H
Authors: Yu Yong Jiang , Yu Xiao Yue
Published: April 2014

Quasi-classical trajectory dynamical calculations of the title reactions have been performed on an accurate NH2 potential energy surface [Poveda LA, Varandas AJC, Phys Chem Chem Phys 7:2867,2005] over the collision energy range of 25-80 kcal mol-1. The reaction cross sections, variation of internuclear distances of N-Ha, N-Hb and Ha-Hb, and the reaction rate constants are reported for various initial vibrational and rotational states of H2 (v=0-3; j=0) molecules. The reaction cross section in the ground vibrational state of H2 and the rate constant over the thermal distribution of initial vibrational states of H2 are compared with other theoretical results and existing experimental results in the literature, showing good agreement.
Pop-In Events and Elastic Deformation of Sapphire Single Crystal during Nanoindentation
Authors: Ke Rui , Zhang Yu Min , Zhou Yu Feng
Published: April 2014

Sapphire single crystal is widely used in many fields because of its excellent properties, as a focus of mechanical test, nanoindentation on sapphire is paid a great deal of attention by researchers. In this manuscript, the maximum load, depth and loading rate effects on the first pop-in event during nanoindentation of sapphire single crystal were discussed, the results indicated that these factors had no effect on the load at which the first pop-in occurred and the extension width of pop-in; the deformation below the first pop-in event was discussed and it could be roughly considered as purely elastic deformation through analyzing.
Influences of Preparation Process on the Orientation and Properties of PZT Piezoelectric Thick Film Generation Materials
Authors: Yu Guo Qin , Shao Yu Ying , Liu Jun Biao , Huo Rong Ling , Li Yan Li , Duan Zhong Xia
Published: April 2014

Abstract: As it's excellent mechanical and electrical conversion characteristics, Piezoelectric material has become an important material for capturing environmental mechanical energy to get electrical energy. In this paper, (100) oriented PZT piezoelectric thick film has been prepared on Pt/Cr/SiO2/Si substrate by sol-gel used PT as transition layer. The influences of preparation process on the (100) oriented degree, ferroelectric properties, dielectric properties and piezoelectric properties of PZT piezoelectric thick film were investigated. Experiment results show that, the increasing of annealing temperature and shortening annealing time can promote PZT piezoelectric thick film growing along (100) orientation. The increasing of annealing temperature results in the decreasing of remnant polarization intensity and increasing of coercive field. Under the frequency of 1 KHz, (100) oriented PZT piezoelectric thick film with thickness of 1.5 m has the dielectric constant ˰̶̿˰́̃̅̆˼˰̈̃́˰̴̱̾˰̇̈̀˰̱̈́˰̵̷̱̱̼̹̾̾̾˰̵̹̈́̽˰̶̿˰̹̅̽̾˼˰̹́̀̽̾˰̴̱̾˰̹́̅̽̾˼˰̴̱̾˰̴̵̵̹̼̳̹̳̈́͂˰̴̹̹̱̹̓̓̀̈́̿̾˰̱̈́̾ڄ˰̹̓˰̀˾̃́£¬0.20 and 0.22, respectively. (100) orientation of PZT piezoelectric thick film can effectively improve the piezoelectric properties of PZT piezoelectric thick film, PZT piezoelectric thick film with thickness of 1.5 m and annealing time of 5min has the better (100) orientation degree, has the piezoelectric constant d33 of 102.5 pC/N.
Keywords: (100) orientation; PZT generation material; ferroelectric properties; dielectric properties; piezoelectric properties
Synthesis of CdSe Quantum-Dots-Sensitized TiO2 Nanocomposites with Visible-Light Photocatalytic Activity
Authors: Shi Yong , Ke Jun , Zhao Qi Dong , Li Xin Yong , Zheng Nan , Xue Fang Hong
Published: April 2014

CdSe Quantum Dots (QDs) sensitized TiO2 photocatylysts were synthesized by a facile sol-gel method at room temperature. The effects of CdSe QDs concentration on the properties of the photocatalysts were studied by XRD, BET, SEM, UV/vis. The photocatalytic performance was investigated by degrading methylene blue (MB) under halogen-tungsten lamp irradiation. The results revealed that the catalysts doped with CdSe QDs show large surface area, small crystal size and narrow band gap. The catalysts doped with 0.05% CdSe QDs possessed the best activity, and the degradation efficiency of methylene blue (MB) is up to 99.2% within 180 min.
Experimental Research on the Magnetic Mechanisms of Zn0.990Co0.010O Diluted Magnetic Semiconductor by Al-Doping
Authors: Gao Qian , Liu Xiao Li , Qi Yang , Sun Ben Zhe , Qi Lian Zhong
Published: April 2014

The effect of Al-doping concentration and sintered temperature (ST) on the structure and room-temperature ferromagnetism (RTFM) of Al-doped Zn0.990Co0.010O nanocrystals was investigated. The experimental results have indicated that all samples have RTFM and are composed of wurtzite ZnO with hexagonal structure without any secondary phases. The crystallization quality is positive related to ST and negative related to Al-doping concentration. When ST is higher than 800°C, the RTFM is dominated by the long rang coupling induced from the conductive carriers of Al3+, since it is increasing with the increase of Al-doping concentration and grain sizes. When ST is lower than 800°C, the RTFM is dominated by localized carriers from oxygen vacancies, since the maximum RTFM belongs to the sample which has the lowest parameters of unit cell.
Saturation Concentration of Gas Pollutants in Photocatalysis
Authors: Xie Hong Yong , Ma Chang Wen , Sun Zhi Guo , Gao Gui Lan
Published: April 2014

Saturation behavior in photocatalysis is investigated for volatile organic carbons (VOCs) and ammonia by using a tubular photoreactor and TiO2nanoparticles, synthesized by a flame chemical vapor deposition (CVD) process. Degradation degree versus initial concentration shows that saturation behavior occurs at different initial concentrations for different gas pollutants. The saturation concentration is obtained by taking as the intersection of the level off part and the tangential line to the rapid change part from the curve of degradation degree versus initial concentration. The saturation concentration for benzene is as low as 0.063 mg/m3, and is up to 720mg/m3for formaldehyde for TiO2nanoparticles synthesized by a flame CVD process.
Surface-Enhanced Raman Scattering for ZnO Observed in Ag@ZnO Core-Shell Heterostructures
Authors: Liu Xue Jiao , Xu Mei , Hu Jian Ling , Li Yan , Li Quan Shui , Lu Yan Zhen , Wang Feng Ping
Published: April 2014

Core-shell Ag@ZnO heterostructures are designed and fabricated by a facile two-step chemical method. The heterostructures are composed of Ag microspheres as the core, on which plenty of small ZnO nanorods grow as the shell. The morphological, structural and Raman properties of the composites were investigated by means of powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman scattering spectra. A strong surface-enhanced Raman scattering (SERS) and Raman red shift of ZnO nanorods were observed in Ag@ZnO core-shell nanocomposites due to the effect of Ag microspheres.
Efficient Desizing of Fabrio Using Partially Purified Thermophillic Amylase Produced by T. sacchari by the Utilization of Agro-Industrial Wastes
Authors: Khan Muhammad Ayub , Qureshi Muhammad Zahid , Dawson Lorna , Rehman Mujadad , Hayat Azam , Maqbool Farhana , Andleeb Farah , Haleem Kashif
Published: April 2014

Thermoactinomyces sacchariwas isolated from hot water springs.Then by utilizing the solid state fermentation techniques,amylasewas obtained, which was partially purified. The partially pu rified enzyme was then used to remove thestarchsize from cloth. Effective enzymaticdesizingrequires the strict control of pH, temperature, water hardness, electrolyte addition and choice of surfactant. It was observed that maximum removal 7.5 g was achieved by soaking the cloth in 100 ml of 0.1M HCl for 2 hours. A maximum of 98.4desizingwas obtained after 90 minutes at 55oC. A maximumdesizingof 98.9 was obtained after 60 minutes of incubation at 55oC.A maximumdesizingof100% was obtained at pH 6.0 at 55oC for 60 minutes. At lower and higher values desizing decreased. When cotton pieces were soaked for 60 minutes at pH 6.0, maximumdesizing(100%) was obtained at 60oC.
The Influence of Anions Additive/CeO2 on Cabbage
Authors: Zhang Di , Li Qing Shan , Li Bai Feng , Hong Wei , Liu Lian
Published: April 2014

In o rder to research the influence of anion additives/ CeO2 on cabbage seeds, taking cabbage seeds as the test material. This paper detected the seeds' germination percentage and protein content by respectively adding unique concentration of anion additives and CeO2 in soil. The results show that different anion additives have distinct influences on seed's growth in the same situation. To be more specific, 1040 can noticeably improve seeds' germination percentage and protein content. Moreover, different contents of 1040 could have various impacts on seeds' germination percentage and protein content. Furthermore, precise content of CeO2 can also significantly improve seeds' germination rate and protein accumulation.
Preparation of Silica Microspheres Coated by Nano-ZrO2
Authors: Yue Chun Xiao , Ding Peng , Zhao Yu , Shi Li Yi
Published: April 2014

Silica microspheres coated by nanoZrO2 were prepared by the sol-gel process using butoxidesolution (TBOZ) as precursor. The nanomicrospheres were formed via hydrolysis and condension reaction of metal alkoxides with the hydroxyl (-OH) of silica microspheres by form Zr-O-Si bonds. The samples were characterized by X-ray diffraction, FT-IR and SEM. Presence of the FT-IR bands with frequencies ranging from 800 to 900 cm-1 can be assigned to SiO vibration, and to ZrOSi stretching vibration. XRD analysis shows obviously the characteristic diffraction peaks of tetragonal (T-ZrO2) in the sample by heat-treatment at 400°C. The SEM image showed that the surface layers of silica microspheres were coated by nanoparticles.
Effect of Substrate's Surface Oxidation State on Optical Absorption Property of Au/Si-NPA
Authors: Fu Xiao Nan , Li Kun , Luo Yan Wei , Li Xin Jian
Published: April 2014

Two types of Au/Si-NPA samples based on different surface oxidation state were prepared by immersion method. Their surface morphology and optical absorption property were also investigated. The results showed, due to the different deposition region of Au nanoparticles, their surface morphology and structure were quite different, and their absorption curves were also different. Optical absorption property of samples prepared on aged substrate was better than those of prepared on fresh substrate, except 15 minutes samples.
Spherical SrMoO4:Eu3+ Phosphors Prepared by Spray Pyrolysis
Authors: Wu Jing Long , Wang Xia , Peng Gui Hua , Liang Zhen Hua , Wang Xiao Feng
Published: April 2014

SrMoO4:Eu3+ micro-spheres with well morphology were fabricated by a one-step and template-free ultrasonic spray pyrolysis method using strontium nitrate and ammonium molybdate as precursors. The as-prepared products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectra (PL). The XRD results indicate that all the XRD peaks can be indexed as SrMoO4 with a pure tetragonal scheelite structure. The SEM photographs show that the sample particles are spheres with regular spherical shape. The excitation and emission spectra demonstrate that the phosphors could be excited effectively by the ultraviolet light with wavelength 394 nm or visible blue light with wavelength 466 nm, and the highest emission peak locates at 615 nm.
Wettability and Surface Roughness Study on RIE Treated Aluminium Deposited Surface
Authors: Retnasamy Vithyacharan , Sauli Zaliman , Hashim Uda , Palianysamy Moganraj , Yeow Aaron Koay Terr , Ayub Ramzan Mat
Published: April 2014

Design of Experiment (DOE) is a technique for optimizing process which has controllable inputs and measurable outputs. As a method of DOE, 24 Full Factorial design is used to study the effect of Reactive Ion Etch towards the surface roughness of aluminum pad and effect of the roughness produced towards the contact angle. Surface roughness analysis is done using Atomic Force Microscop (AFM). Contact angle is measured using AutoCad software from the images captured from droplet test. This contact angles must be more than 90° for non-wetting profile or less than 90° for wetting profile. This work is also done to understand the interaction between the process parameters and how each parameters will affect the etch rate. The results are analyzed which shows that the increase in surface roughness produces an increase on the contact angle and vice versa.