bluuebunny/crossref_metadata_2025 huggingface dataset:
Capacity Management System of High Speed Railway in China
Authors: Li De Wei , Han Bao Ming , Li Xiao Juan
Published: April 2011

In order to improve the utility of infrastructure of high speed railway, it is very important to manage the capacity. This paper analyzed the characteristics of high speed railway capacity from a few points of view. Then, it proposed a method of capacity calculation and capacity consumption assessment respectively. Decision support system called CRH-CMS is developed. The use of field data proves that the model is effective and the system is practical to use.
Influence Analysis of CCD Miss-Distance and Corresponding Research of τ Compensatory Technology Based on Finite Memory
Authors: Huang Hai Bo , Wang Wei Hua , Zuo Tao
Published: April 2011

A series of time lag taches result in miss-distance lag in the coarse tracking system of APT system, which will greatly influence the tracking precision of the whole FSO communication system. In order to provide theory basis for determining the sampling frequency and components with time lag character, the influence on systems stability resulted from phase margin loss caused by miss-distance lag is analyzed in detail. To eliminate the influence caused by miss-distance lag, finite memory based τ Compensatory Technology is put forward, which has characteristics of simple program realization, low CPU overhead and high precision, experiment result shows that miss-distance lag based on τ Compensatory Technology is feasible and effective to practical APT system.
Numerical Simulation and Analysis for Surface Defect Prediction in the Hot Bar Rolling Process
Authors: Jin Jie , Huang Gang
Published: April 2011

Establishment of numerical model for hot rolled bar and analysis the changes from the discrete points on surface during the hot bar rolling process (includes velocity, displacement, equivalent stress, equivalent strain). And the position of surface defects can be effectively predicted form this. Compared with the actual hot rolling bar production, numerical simulation was in good agreement with it. So that the numerical simulation analysis has practical significance for optimizing processing parameters and process design to ensure product quality.
An Analysis on the Scale Economies and Scope Economies after the Reorganization of China Unicom
Authors: Zhao Jian Na , Zhang Xin Qiao
Published: April 2011

Telecom industry, characterized by techno- economic, presents some features of scale economies and scope economies on the basic character of its natural monopoly. The question is whether it continues to exist after the reorganization of the Telecom industry. This paper mainly analyzes the features of scale economies and scope economies after the reorganization of China Unicom on the application of transcendental logarithmic cost function to show the existence of scale economies and scope economies after the reorganization.
A Novel Adaptive Routing Algorithm for Network-On-Chip
Authors: Jia Jia , Zhou Duan , Zhang Jian Xian
Published: April 2011

In this paper, we propose a novel adaptive routing algorithm to solve the communication congestion problem for Network-on-Chip (NoC). The strategy competing for output ports in both X and Y directions is employed to utilize the output ports of the router sufficiently, and to reduce the transmission latency and improve the throughput. Experimental results show that the proposed algorithm is very effective in relieving the communication congestion, and a reduction in average latency by 45.7% and an improvement in throughput by 44.4% are achieved compared with the deterministic XY routing algorithm and the simple XY adaptive routing algorithm.
Numerical Simulation of Flow around Cylinder Using the Lattice Boltzmann Method Based on Guo Boundary Condition
Authors: Li Hang , Liu Yong Hong , Wang Ya Zhou , Ma Jian Ming
Published: April 2011

In this paper, the lattice Boltzmann Method is applied to simulate incompressible steady flow around a cylinder. The simulation model is based on D2Q9 lattice model and Guo boundary condition. Different Reynolds number and cylinder position in the flow field is considered to acquire corresponding velocity, vorticity, pressure and kinetic energy. The conclusions demonstrated in this paper could be useful for the project like construction of ocean platform, cooling tower or high chimney and so on.
Development of an On-Line Thermocouple Auto-Calibration System for Ceramic Kilns
Authors: Yang Shu Lian , He Jian Ting , Sheng Cui Xia , Zhang Yu , Qin Chang Wei , Chen Shi Bao
Published: April 2011

An on-line thermocouple auto-calibration system using wireless communication module for ceramic kilns has been developed. It is consist of the temperature measurement module for the ceramic kilns, Wireless transmitting and receiving module, data processing and results display module of the PC. For the requirement of thermocouple calibration for ceramic kilns, the wireless data transmission module is used to transmit temperature data in the system. Finally, the data is transmitted to PC through serial interface, it is processed and the calibration results are derived by PC. Its performance fully met calibration requirements. The calibration efficiency of the system is greatly enhanced and the additional man-made errors are reduced. The proposed system ran well in practice.
Application of Numerical Simulation on Cast-Iron Pneumatic Hammer Housing
Authors: Mi Guo Fa , Chen Li Lin , Liu Bao Zhong , Wang Hai Yan
Published: April 2011

The Pro/E software was used to generate 3-D model of pneumatic hammer housing casting. The solidification process of the casting was simulated by the numerical simulation software, View Cast. The location and scale of the shrinkage defects were shown in the results. The risers were designed by the View Cast software based on the simulation results. The reasonable risers were obtained after the optimization on the numerical simulation. And the parameters of gating system were got according to the simulation results calculated by the gating system designing function of View Cast. Then the solidification results demonstrated that the risers and pouring system could be planned by View Cast effectually. The reasonable casting process was obtained and the process has been proofed by the productive practice.
A Research of Principle and Application of Communication Interface between MBMS and DBMS in DDS
Authors: Ye Qiong Wei , Song Guang Xing , Feng Yu Hui , Nie Qiu Yun
Published: April 2011

The communication interface technology of Model Base Management System (MBMS) and Database Management System (DBMS) is one of the key technologies for successful implementation of Decision Support System (DSS). This paper firstly introduces the concept model of communication interface between MBMS and BMS in DDS. Then it makes an analysis of the principle of communication interface between MBMS and BMS in DDS. Based on the analysis, three ways of its implementation are proposed: Standard Format Method, Function Method and Embedding Method, which finally realize the ODBC-based application of communication between MBMS and DBMS in DSS. This paper is of great reference significance for solving communication problems among database, model base, data warehouse, knowledge base, expert base and method base, and for accessing heterogeneous data or even extreme data in such emerging Decision Support Systems as Distributed DSS, Group DSS and Intelligent DSS.
Research of the Parameter for the Piston’s Configuration in the Tile Press’s Moving Beam
Authors: Hu Wei Wen , Zhang Bai Qing , Fen Jing Hua
Published: April 2011

Through the geometry models of ceramic powders flan and move beam and piston established, and the actual ceramic powders parameters and the pressure of tile press defined and loaded, the individual effects were analyzed in the single-acting and the dual-acting piston-cylinder in the process of the power compaction, which also offered the theory basis for the design in the move beam in the future at the same time.
Plum Tree Visualization Based on SpeedTree
Authors: Bai Zhi Yong , Huang Xin Yuan
Published: April 2011

Plum Blossom as the Chinese traditional flowers may be unique all over the world and has the first right of access to international registry of flower. In this paper, the SpeedTree softwareSDK is used to create a large plum tree forest with the graphics texture mapping technique, and the plum tree image maps express the geometric model of the surface material, which constitutes a visual image of the graphic objects. It is significant for non-destructive study of plum and virtual garden.
Effect of Fiber Volume Fraction on High Temperature Creep of Al2O3-SiO2(sf)/AZ91D Composite
Authors: Tian Jun
Published: April 2011

Constant stress tensile creep tests were conducted on AZ91D–20 vol.%, 25 vol.%, and 30 vol.% Al2O3-SiO2short fiber composites and on an unreinforced AZ91D matrix alloy. The creep resistance of the reinforced materials is shown to be considerably improved compared with the matrix alloy. With the increasing volume fraction of short fibers, the creep resistance of AZ91D composites is improved, and their creep threshold stresses are also increased accordingly. Because of the increasing volume fraction of short fibers, loads of bearing and transmission of short fibers will increase, and thus the creep resistance of AZ91D composites further improves, but the precipitation of β-Mg17Al12precipitate increases in the number, it is easy to soften coarse, so that threshold stress of AZ91D composite does not increase greatly.
The Mean Projected Range and Range Straggling of Nd Ions Implanted in Silicon Carbide
Authors: Qin Xi Feng , Li Shuang , Wang Feng Xiang , Liang Yi
Published: April 2011

In view of the influence of the projected range, the range straggling, and the lateral deviation of ions in materials on the property of device in the fabrication of photoelectric integration devices by ion implantation, the mean projected ranges and range straggling for energetic 200 – 500 keV Nd ions implanted in 6H-SiC were measured by means of Rutherford backscattering followed by spectrum analysis. The measured values are compared with Monte Carlo code (SRIM2006) calculations. It has been found that the measured values of the mean projected range Rp are good agreement with the SRIM calculated values; for the range straggling △Rp, the difference between the experiment data and the calculated results is much higher than that of Rp
Design and Implementation of a Manufacturing Business Collaboration Platform Based ESB Technology
Authors: Sui Xin , Zhu Yun Long , Nan Lin , Wu Jun Wei
Published: April 2011

Enterprise Service Bus (ESB) technology, which is one of the implementation of the infrastructure of Service-Oriented Architecture (SOA), is put forward to solve various heterogeneous problems in enterprise information sharing and the management system integration. First, this paper introduces the definition and technical features of ESB and then, shows the design and implementation of an ESB-based Manufacturing Business Collaboration Platform (MBCP), which is used to solve the problems of the business integration in manufacturing industry area. Finally, we presented the application of MBCP in a steel plant as an example to illustrate the effectiveness of MBCP.
Optimal Power Control of Smart Grid Based on Neural Network Optimization
Authors: Zhang Li Yan , Quan Shu Hai
Published: April 2011

This paper presents a neural network based optimal control approach for the power allocation problem of smart grid. Firstly the optimal control framework which consists of center control layer, area control layer and generator control layer is presented. In order to reduce computation time of optimal control, the neural network optimization method and schematic diagram is proposed. Simulation is implemented in a modified IEEE30-bus power system comprising 6 conventional generators and a wind plant. Simulation results demonstrate that the proposed neural network optimization approach is satisfied the demand of computation time and the optimal power controller can allocate the power into loads reasonably and cope with the fluctuation of the load and renewable energy source’s output power.
A Standing Wave Ultrasonic Motor Using Longitudinal Vibration Transducers
Authors: Liu Jun Kao , Xie Tao , Chen Wei Shan , Jia Chang Hua
Published: April 2011

A new type standing wave ultrasonic motor is proposed in this study. In this design, three longitudinal vibration transducers are clamped on the inner side of a ring with driving teeth by screws. Bending standing wave can be generated in the ring by the longitudinal vibrations of the transducers. Thus, oblique linear simple harmonic vibrations are formed on the teeth, which can drive the rotor by frictional force. The structure and working principle of the proposed design are introduced. The motor is designed and analyzed by using FEM method. A standing wave is gained after the degeneration between the bending vibration of the ring and the longitudinal vibration of the transducer. The test results of the prototype motor verify the feasibility of the proposed design.
Multi- Universal Coupling Phase Modeling and Optimization Base on Floor Vibration Control
Authors: Song Hai Sheng , Shi Wen Ku , Long Yan , Guo Fu Xiang , Fang De Guang
Published: April 2011

Torsional vibration of drive shaft has a great influence on the floor vibration, Rational arrangement of phase of multi-universal coupling can attenuate vibration. Accord to the vibration of the floor of one light bus, theoretical model has been established and Optimization program has been operated .The results of test validation and simulation show that the optimization scheme is effective and reasonable.
Computer Simulation Model for Spherical Particle Filled Composite Materials
Authors: Chen Zhuo , Huang Zhi Xiong , Zhang Ming , Shi Min Xian , Qin Yan , Mei Qi Lin
Published: April 2011

This paper introduced a computer simulation model for composite materials which was reinforced by spherical particles. We introduced its algorithm and visualize the model with different particle volume fraction. In order to evaluate the uniformity of the particle distribution, we estimated Particle Center Density and standard deviation of minimal sphere distance.
Image Reconstruction Algorithm for Ultrasound Tomography Based on Transmission Mode
Authors: Li Yan Qiu , Liu Shi
Published: April 2011

One of the key issues in ultrasonic tomography is the calculation of sensitivity and image reconstruction based on the sensitivity. A method is developed to calculate the sensitivity of ultrasonic tomography in rectangular area in this paper. On this basis, numerical modelling calculation of different substances distribution in a rectangular area is made of by using LBP algorithm, the standard Tikhonov regularization method and the Landweber iteration method respectively. Reconstruction simulation experiments of changing the quantity of pixel is conducted. The results show that imaging results of Tikhonov regularization method and the Landweber iterative method are consistent with the original image for the overdetermined problem and superior to those reconstructed by LBP algorithm. The image quality of Tikhonov in the underdetermined problems is poor than that in overdetemined problem and still better than that in the Landweber and LBP algorithm. Compared by numerical simulation, Tikhonov regularization method in both overdetermined or underdetermined problems are better than Landweber iteration and LBP algorithm, and LBP algorithm is only suitable to qualitative analysis.
Travel Time Prediction of Multi-Source Historical Data Fusion
Authors: Liu Wen Ting , Wang Zhi Jian , Yan Qin
Published: April 2011

For improving the travel time predication accuracy, a travel time predication model based multi-source historical is proposed. The model analyzes the different features between the loop detector data and the probing vehicles data, and creates traffic rules based on traffic patterns through data mining. Finally, the experiment of the navigation system based on multi-source historical data fusion is given. The results show the effectiveness of the model performs well.
Research on the Location and Segmentation Technologies in Palmprint Identification
Authors: Xu Shuang , Suo Ji Dong , Zhao Ji Yin
Published: April 2011

In this paper, a method of palmprint segmentation and location is proposed. The proposed method focuses on region of interest (ROI) extraction of palmprint images which involve transition and rotation. Firstly, binary of palmprint image is used to define the edge of palmprint. Then we separate the fingers and palms and find the two valley points of the index finger and middle finger, ring finger and little finger. Finally, rotate image based on the two valley points and correct image position and create coordinate system according to valley points to determine ROI. This method provides a necessary preprocessing for further feature extraction and matching.The effectiveness of the proposed method is verified using the PolyU palmprint database.
The Status and Development Trends of Virtual Private Network Technology
Authors: Zhang Kun , Wang Hai Feng , Ma Yu Chun , Li Zhuang
Published: April 2011

Virtual Private Network (VPN) refers to rely on the ISP (Internet service providers) and other NSP (Network service provider), in the public network, to establish a dedicated data communication network technologies. In the virtual private network, between any two nodes connected no dedicated network for the traditional end-to-end physical link, but to use a public network composed of dynamic resources. VPN technology can reduce the internal network building costs, improve user network operation and management flexibility, and enable communication between computers and private circuits on computer communications with the same security.
Study of Wake Characteristics of a Horizontal-Axis Wind Turbine within Two-Phase Flow
Authors: He Ping , Chen Nai Chao , Hu Dan Mei
Published: April 2011

The two-phase flow is addressed for the more accurate estimation of the wake characteristic for the horizontal-axis wind turbine operating in the complexly unsteady environmental states. The computational fluid dynamics (CFD) method is implemented for performing the three-dimensional wind turbine using the simulating software tool of FLUNT. Three types of environmental states, single-phase flow, liquid-gas flow and solid-gas flow, are performed for the comparison of velocity and pressure distribution to derive the specify feature for wind turbine within two-phase flow environmental state. The calculated results shows that there has the similar evolutional tendency of velocity distribution for both single- and two-phase flows and the velocity decrement at the distance of 20 meter away from wind turbine still reach to 80% of inflow speed. But the turbine blade within two-phase flow is subject to the unsteady flow with the larger velocity gradient compared with that within single-phase flow. For the static pressure, large difference occurred in these three types of environmental state reveals that the second material in addition to atmospheres causes the prominent influence of aerodynamic force and its power coefficient. The results exhibit that wind turbine within solid-gas flow has the largest power coefficient that those within the gas and liquid-gas flows.
A Small World Routing Protocol in Wireless Sensor Networks
Authors: Xu Wen Jun , Sun Li Juan , Guo Jian , Wang Ru Chuan
Published: April 2011

In order to reduce the average path length of the wireless sensor networks (WSNs) and save the energy, in this paper, the concept of the small world is introduced into the routing designs of WSNs. So a new small world routing protocol (SWRP) is proposed. By adding a few short cut links, which are confined to a fraction of the network diameter, we construct a small world network. Then the protocol finds paths through recurrent propagations of weak and strong links. The simulation results indicate that SWRP reduces the energy consumption effectively and the average delay of the data transmission, which leads to prolong the lifetime of both the nodes and the network.
Configuration Design and Kinematic Analysis on Some New 2R1T 3-DOF Parallel Robots
Authors: Zhu Da Chang , Xiao Fan , Wang Liang , Gu Qi Hua
Published: April 2011

Based on the screw theory,the paper presents a systematic method for structural synthesis of the two rotations and one translation parallel robot.According to the reciprocal product between kinetic screw and constrainted screw in screw theory.This method firstly creats possible branch structures and then generates diferent models of mechanism.By this method,the paper carries on the structural synthesis of the two rotations and one translation parallel robot,and also lists some of the mechanisms including a few new ones. Analyzsis solution of direct and inverse position.The dynamic simulation was conducted using the software of Adams.
Errors Analysis and Calibration on Measuring Mechanical Arm for EVA Spacesuit Ergonomics Research
Authors: Wen Jian , Zhou Lei , Zhang Chun , Liang Tong Fen
Published: April 2011

A combined coordinate measuring mechanical arm (CCMMA) was developed to test the operational ability of astronaut in the EVA spacesuit. The equipment measures the space region coordinates of the astronaut’s hand-reach while forces act on a handle. The homogeneous transformation equations of CCMMA are established based on Modified Denavit-Hartenberg (MDH). Measurement error was analyzed and distance error model of CCMMA was set up to improve measurement precision. The improved genetic algorithm is applied to the identification of CCMMA structure parameters. The calibration experiment of CCMMA was carried out using such model and algorithm. The result showed that with identification, the repeatability and length measurement precision were improved by 5.38 and 3.11 times respectively.
On-Line Defect Detecting Method Based on Kernel Method
Authors: Xu Ke Jia , Chen Bin , Zeng Li
Published: April 2011

The conflict between accuracy and speed is one of the most well-known dilemmas of the real-time defect detecting system. This paper presents a real-time defect detecting algorithm based on Kernel principal component analysis (KPCA). KPCA-based feature extraction have recently shown to be very effective for image denoising, however the Normal KPCA method is time-consuming. In our method, we propose a progressive algorithm to speed up the reconstruct process while improve accuracy. Experimental results demonstrate that our method is dramatically better than Normal KPCA Pre-image method in terms of speed and performance.
Research on Key Technologies of College Computer Room Billing Management System
Authors: Zhang Kun
Published: April 2011

According to the actual situation of some colleges, we will apply the database technology and its development principle combine the practice, follow the design procedure of database development, and design a billing management system for universities’ computer labs.
Suppression of the Conducted Interference of Switching Power Supply
Authors: He Hong , Bao Shuai , Li Hang , Zhang Da Jian , Hou Ming Feng
Published: April 2011

Along with the power electronic technology constantly to high frequency change, miniaturization, direction, switching power supply the electromagnetic compatibility problems appeared more and more important. This paper mainly analyses the switch power electromagnetic interference source and the coupling channels, and with half a bridge type switch power converter for example analyses of switch power supply conducted interference. On the basis of existing circuit model, calculates and analyzes the an active filter, thus for suppression of switch power supply conducted interference provide theoretical basis.
A Kind of TD-SCDMA Download System Based on Cloud Computing
Authors: Chen Xiang , Zhang Yong
Published: April 2011

TD-SCDMA communication platform based on concept of cloud computing is the natural trend of mobile communication development. Based on introduction of related concept of cloud and TD-SCDMA communication platform, the paper combined TD-SCDMA wireless communication network platform and cloud computing and designed wireless communication network download system under this concept. The communication manage module of system completes signaling transmission, data transmission control and monitoring. The Flash module block manage memory chip. Data block multi-threaded simultaneous downloads, combining with high-level protocol stack module, and the network data backup as well as wireless download transmission was implemented based on concept of cloud computing. System stability and efficiency has been proved in the platform development process.
Study on Thermal Boundary Condition of Manufacture Process for Composite Pressure Vessel
Authors: Ma Li , He Lu Ju , Wang Hai Bo
Published: April 2011

The heat convection was the main heat exchange in the autoclave by which composite pressure vessel was cured. To determine the heat convection coefficient, the combination of theoretical calculation and temperature test is absolutely necessary. In the theoretical calculation, the determination of the heat convection coefficient is considered as an inversion problem of thermal conduction. By adjusting convection coefficient value in the finite element calculation, optimization method was employed to obtain a good agreement between calculated temperature and measured temperature. In the temperature test, the metallic liner of pressure vessel was used as test component to record temperature data which was compared with the calculated temperature. The results present the equivalent thermal boundary condition for the simulation of curing process of pressure vessel.
Reconstruction and Mesh Simplification of Tooth Model
Authors: Zhou Lang Ming , Zheng Shun Yi , Zhou Yang , Li Qing
Published: April 2011

A method for reconstruction of tooth model based on rotate scanning using structured light match technology was proposed. And an algorithm of mesh simplification of the surface point of tooth model using section lines sampling with fixed angles was achieved, which can provide regular surface mesh points for finite element method (FEM). Experiments showed that the method and algorithm could generate accurate surface mesh model which can provide excellent data support for finite element biomechanical model analysis.
A Method of Self-Adaptive Controlling Temperature Fluctuation of Display Cabinet in Dynamic Ice-Storage System
Authors: Guan Wei Hua , Li Li Fu , Lin Yong Man
Published: April 2011

Dynamic ice storage system has advantages of energy-saving by using electricity price difference of the different period. Food in display cabinet requires small temperature fluctuation to prolong preservation time. Considering the questions of energy consumption and unable to adopt the traditional method of halting and running compressor to control center temperature fluctuation in display cabinet, the paper provides dynamic ice storage system to cool display cabinet. When the wind speed keeps in suitable space, according to environment temperature, humidity and wind change, self-adaptive adjusting cooling water pump flow can maintain the center temperature within a certain range, and reduce center temperature fluctuations in display cabinet by controlling inverter frequency using PLC. Experiments prove that when environment temperature change range is 20°C to 32°C, and relative humidity is 40% to 90%, if not adopting PLC control pump flow, the temperature difference is 2.5°C, on the contrary, temperature difference is 1.3°C.
The New Design of Children Safety Device in the Car
Authors: Shen Lei , Jiang Xue Huan
Published: April 2011

This document proposes a new type of design for protecting children safely in the car which can increase children's comfort and safety in the car. It is designed from the point of clothing that combines children clothing with car seat cover of automobile, and it may promote collaborative development of automotive industry and garment industry.
Effect of Grinding Methods on the Performance of Ground Fly Ash
Authors: Lu Zhong Yuan , Xu Xun , Li Jun
Published: April 2011

In this study, coarse fly ash was ground with laboratory ball mill, vibration mill and jet mill respectively. The powder characteristic of ground fly ash was tested by laser particle size analyzer and scanning electron microscope. And the performance of cement containing different ground fly ash was also studied. It was observed that the characteristic value of fly ash ground by ball mill, vibration mill and jet mill was 13.543 μm, 13.403 μm and 17.344 μm, respectively, when average particle size was about 25μm. And the uniformity coefficient of fly ash ground by ball mill, vibration mill, and jet mill was 1.26, 1.24 and 1.38, respectively. Specially, the mortar strength was increased when 10 to 20 percent of ground fly ash was added. And the highest fluidity of mortar was obtained when 30 percent of fly ash ground by jet mill was added.
Influence of Silica Fume on the Performance of PALC
Authors: Ren Shu Xia , Gao Zhen Guo , Tian Xiu Shu
Published: April 2011

The influence of silica fume on the Performance of PALC was studied and the mechanism was analyzed by XRD and SEM in the paper. The results shows that the addition of 4w/% silica fume is favorable for splitting strength of PALC pastes, which is because high volcanic ash activity and the micro-powder filling dense mechanism brought about by silica fume obviously occur.
Analysis on the Pozzolanic Effects of Phosphorus Slag Powder in Concrete
Authors: Qi Gui Hai , Peng Xiao Qin
Published: April 2011

Phosphorous slag, one of the pozzolanic active materials, is a by-product from the production of yellow phosphorous. In this paper, phosphorous slag was ground and adopted to prepare concrete as a mineral admixture. Specific strength method was used to assess the influences of phosphorous slag content on the pozzolannic effects in concrete with different age. The results indicated that with the increase of phosphorous slag content and age, the pozzolanic effects were enhanced in concrete. Phosphorous slag powder is beneficial to the development of long-term strength of concrete.
Influence of Cement Particle Size Distribution on Strength of Hardened Cement Paste
Authors: Zhu Bao Lin , Huang Xin , Guo Ye
Published: April 2011

On the basis of the principle for the highest filling degree of cement hydrates, it is synthetically considered that a matching connection between hydration of cement, volume increment of solid phase and packing density of cement paste, a calculation method for a connection between cement continuous particle size distribution and strength of hardened cement paste is developed and tested by experiment. Based on above-mentioned analysis, a tentative research on the effect of particle size distribution of cement on strength is carried out.
A Calculation Method for Packing Density of Powder in Paste with Continuous Grain Size Distribution
Authors: Guo Ye , Huang Xin , Zhu Bao Lin
Published: April 2011

By regarding the powder particles warpped with water film as compounded particles, the packing density of powder particles in actual paste system is transformed into the packing density of compounded partcles in imaginary dry-particle system. Based on Stovall Model, a calculation method for packing density of powder with continuous particle size distribution in paste is developed, and the parameters in the method are dentified by experiment. This calculation method could be used to simulate the packing density of cementitious materials such as cement, fine slag, and fly ashes.
Influence of Mineralogical Origin of Limestone Powder on the Performance of Complex Binder Material
Authors: Wang Qin , Chen Jia Long , Zhang Chang Cheng , Niu Wei
Published: April 2011

The effect of mineralogical origin, elemental component, crystal structure of three types of limestone powder on the fluidity of cement-limestone paste and mortar was investigated. The results show that the limestone powder originated from the mine of limestone and river pebble have better water-reducing effect, which is closely correlated with the main components of Calcite and Dolomite. These two mineral have relatively regular, orderly and perfect crystal structure with few defects and unfilled pores which are liable to adsorb more water and water-reducing agents. On the contrary, the limestone powder derived from the mine of sandstone has nearly no water-reducing effect which is ascribed to the large amount of clay mineral which exhibit lamellar structure leading to the large quantity of consumption of water.
Research on the Influence and its Mechanism of an Alkali-Free Hardening Accelerator on the Performance of Concrete
Authors: Gao Zhen Guo , Ren Shu Xia , Han Yu Fang , Liang Huzi Hong
Published: April 2011

The influence of an alkali-free concrete hardening accelerator on the performance of the concrete was studied, the hydration heat and the rate of the hydration heat the corresponding cement with and without the accelerator addition were tested by the calorimeter, the hydrates of them were analyzed by X-ray diffraction (XRD), and the acclerating mechanisms were analysied in this paper. The results show that the compression strength of the tested concrete (with the accelerator addition) have be enhanced repectively by 43%, 47%, 39% and 31% at the age of 1days, 3days, 7days and 28days compared with those of the controlled concrete (without accelerator addition), the hydration rate and the amount of the hydrates of cement with the accelerator have also be increased significantly at different hydration time. The reason for causing the above results is because of the role played by Calcium formate, Crystal embryo and Ferric sulfate together.
Research on Fire Retardant Performance of Chinese Fir with the Compound of Disodium Octaborate Tetrahydrate and SiO2 Gels
Authors: Ye Qing Qing , Qian Xiao Qian , Lai Jun Ying
Published: April 2011

The environmental fire retardant mentioned in this paper was compounded of disodium octaborate tetrahydrate and silicon dioxygen(SiO2)gels. Specimens of Chinese fir were impregnated with the compound by pressure and its fire retardant performance was studied. Results showed that, the anti-loss performance of disodium octaborate tetrahydrate was improved obviously. Compared with the untreated specimen, total heat release of the treated specimens decreased by 44.5% on average, while heat release rate decreased by 50.85% on average and ignition time prolonged obviously, which indicates that this compound possess good fire retardancy effect
Effect of Salt Admixtures on Air Content in Fresh Air-Entrained Concretes
Authors: Li Qin Fei , Ge Yong , Yang Wen Cui , Yuan Jie , Yu Ji Shou
Published: April 2011

Combined with the foam stability of air-entraining admixtures (AEAs), the effect of salt admixtures (including CaCl2, Ca(NO3)2, Na2SO4 and NaNO2) on morphology of air-voids in cement paste with a couple kinds of air-entraining admixtures (including SJ-2 and DH-9) was examined by means of SEM. In accordance with foam stability and the morphology, air content of fresh concrete was studied and analyzed more deeply. The results pointed out that these salts mitigated the foam stability of SJ-2 solution, and the deteriorated effect of CaCl2 and Ca(NO3)2 was more obvious. By contrast, these salts seemed to make no difference to the foam stability, but CaCl2 and Ca(NO3)2 reduced the foaming power of DH-9 solution. The walls of air voids in cement paste without using AEAs were compact. Differently, it was a distinct shell that formed around most of the entrained air voids with AEAs. This shell connected with capillary pores. For SJ-2 mixed, the air content of fresh air-entrained concretes was decreased by CaCl2 and Ca(NO3)2, but was enhanced by Na2SO4 and NaNO2; for DH-9 mixed, with the increasing usage of CaCl2, Ca(NO3)2, Na2SO4 or NaNO2, the air content was rising gradually.
An Experimental Research on Basic Mechanical Properties of Concrete with Used Rubber Powder
Authors: Wang Bao Min , Liu Wei , Zhao Li Yan
Published: April 2011

How to deal with used rubber has become a difficult problem worldwide. Adding powdered used tires in certain grain sizes to cement concrete can modify cement concrete, which is also a nuisance-free treatment and rational utilization thereof. In the early stage of research work, the author found that the rubber concrete mixed with fine used rubber powder whose grain diameters are 80, 100, 120 meshes showed a good anti-freeze durability. Based on these, the basic mechanical properties of rubber concrete within that grain size range are studied in this paper. The relations between axial compressive strength and cubic compressive strength, splitting tensile strength and cubic compressive strength are established to provide a design basis for engineering applications.
Experimental Study on CaCO3 Whisker-Reinforced Fiber Cement Mortar
Authors: Cao Ming Li , Yao Hang , Wang Li Jiu
Published: April 2011

As a kind of monocrystal reinforcing material, CaCO3 whisker has good characteristics of high strength, high module and high thermal stability. This research aims to optimize the microscopic structure of fiber cement mortar by adding CaCO3 whiskers and improve the macroscopic mechanical properties. The results showed that CaCO3 whiskers increased the flexural and compressive strength of cement mortar at 3d age by 29.5% and 19.8% at maximum respectively, which fell to 7.2% and 13.0% at 28d age; when CaCO3 whiskers content was 10% and polypropylene fibers content was 0.05%, compared with the pure cement mortar, the flexural and compressive strength were increased by 32.4% and 29.4% at 3d age and 7.6% and 4.6% at 28d age respectively; when the fiber length was 9mm, the composite effect of whiskers and fibers was more ideal; through the SEM analysis, the reinforcing mechanisms of CaCO3 whiskers and polypropylene fibers in cement mortar were discussed.
Theoretical and Experimental Research on Compressive Strength of High Fly-Ash Content Concrete
Authors: Ai Hong Mei , Wang Li Jiu , Wei Jing , Bai Jun Ying , Lu Pu Guang
Published: April 2011

Introduced the concept of “Cementitious Coefficient” of fly ash, theoretical formula of strength of HFCC at a certain age was found with two variables: actual water-binder ratio and micro-aggregate-binder ratio. Development regularity of compressive strength of HFCC was studied and formula of long-term strength coefficient D28t was settled. Influence of actual water-binder ratio and micro-aggregate-binder ratio on long-term strength of HFCC was analyzed. Experimental results showed that along with the single-factor increase of actual water-binder ratio and micro-aggregate-binder ratio, growth rate of long-term strength of HFCC increased; influence of actual water-binder ratio was deeper than that of micro-aggregate-binder ratio.
Study on Performance of Recycled Aggregate Concrete
Authors: Yao Shao Wei , Gao Zhen Guo , Wang Chang Rui
Published: April 2011

The properties of recycled coarse aggregate and the slump, the physical and mechanical properties and durability of recycled aggregate concrete were studied through tests. The results indicate that the slump, compressive strength and durability of concrete with recycled aggregate are lower than that of concrete with natural aggregate when recycled coarse aggregate fully absorbs water. However, the slump can be similar to that of concrete with natural aggregate. The properties of recycled aggregate concrete can be improved by strengthening the recycled coarse aggregate, and it is also found that the recycled coarse aggregate strengthened by grinding is superior to that soaked by chemical solution.
Overview on a Project of Recycling and Utilization of Construction and Demolition Waste in Frame Structures
Authors: Li Fei , Cheng Jia Long , Zhou Wen Juan
Published: April 2011

An overview on a project of recycling and utilization of construction and demolition waste was presented in the paper. The waste was used after being crushed to aggregate size. The concrete incorporating both coarse and fine recycled aggregate was ready-mixed in concrete plant for the field application. The project has been proved to be a successful utilization of recycled construction and demolition waste in Beijing after using for more than 3 years.
Durability Improvement of Concrete in the Environment of Compound Salt and Freeze-Thaw Cycles by Incorporating Mineral Additives
Authors: Hu Ming Yu , Peng Jin Sheng , Ding Cheng Ping , Chen Jian Yi
Published: April 2011

Durability improvement of concrete in the complex environments of chloride, sulfate and freeze-thaw, by incorporating compound mineral additives of fly ash, slag, diatomite and zeolite in concrete, was studied through the approach of orthogonal array testing and related analysis. The results show that zeolite and diatomite play a dominant role in improving the durability of concrete in the complex environments, but the role of fly ash and slag should not be ignored. A reasonable combination of the mineral additives can effectively improve the durability of concrete in the complex conditions without lowering or even increasing the early and later strength of concrete.
Study on Compressive Strength of Recycled Aggregate Brick with Construction Waste
Authors: Zhou Li An , Chen Jia Long
Published: April 2011

Recycling and reusing construction waste has become one of the focus issues which should be solved urgently in China with the rapid urbanization, construction of new countryside and large scale urban renewal. There are some researchers take study on the recycling and application of construction waste, but hasn’t systematic study about compressive strength of recycled aggregate brick until now though production and application of recycled aggregate brick is an important approach to reuse construction waste. This test has discussed the impact on the compressive strength of recycled aggregate brick due to recycled aggregate maximum particle size and fine particle content, water-cement ratio, cement-aggregate ratio, forming pressure and curing mode. These results showed that the finer maximum particle size, the higher fine particle content, forming pressure, curing temperature and humidity have notable impact on the compressive strength of recycled aggregate brick.
Experimental Study on Size Effect of Compressive Strength and Deformation Properties of Large Size Fly Ash Concrete
Authors: He Xi Xi , Lin She Yong , Zhen Xue Cheng
Published: April 2011

The authors experimentally studied the size effect of axial compressive properties of concrete cube and slenderness ratio of 2:1 prism with cross-section side length of 100mm to 800mm in this paper. Commercial concrete was used for test specimens. Specimens were cast and cured outdoors. To highlight the size factors, accumulation of sand on the end surface of the specimen was used to eliminate the end cyclo-hoop effect. The test results show that, in the case of eliminating the end restraint, failure modes of the prism and the cube are the same. There isn’t determined relationship between the cubic compressive strength and cylinder axial compressive strength of concrete, in the case of the specimen slenderness ratio not more than 2 to 1. However, the decline trend of cylinder axial compressive strength with size is slightly greater than the cubic strength. Fly ash concrete, ordinary concrete without fly ash and fiber reinforced fly ash concrete show different size effects. Size effect for concrete with 40% fly ash replacement of cement significantly reduced. The experimental results also show that, strength, elastic modulus and ultimate strain of concrete are all size-dependent. But there are different size effect trends between strength and deformation properties. Ultimate strain of concrete decreases as size increases, and more attention should be taken to this point.
Influence of Permeability of HCSA Expansive Agent on High Volume Fly Ash Concrete
Authors: Hou Fang Fang , Liu Juan Hong
Published: April 2011

Based on the rapid determination of chloride diffusion coefficient with NEL method and pore structure analysis, the influence of HCSA expansive agent on chloride diffusion coefficient of concrete has been investigated. Besides, the effects of chloride diffusion coefficient of Water-Cement ratio on HCSA expansive concrete have been also analyzed. The results show that on the condition of 55% mixing amount of fly ash, the chloride diffusion coefficient of concrete of no HCSA is 1.96×10－8cm2/s, which is classified moderate. While the concrete mixing HCSA is about 0.62×10－8cm2/s, the permeability belongs to inferior. The effects of permeability of HCSA mixing amount on concrete is not obviously. The Water-Cement ratio affects the concrete permeability. Under the experimental conditions, the water-cement ratio of 0.4 can achieve better effect of the HCSA expansion; Furthermore, the mercury intrusion further verified that incorporating proper amount of HCSA can make the internal structure dense and improve the density and impermeability of concrete.
Influence of the Pretreatment on the Concrete Chloride Diffusion Coefficient
Authors: Li Jia Cheng , Guo Wen Ying , Wu Jing Wei , Yang Yi Bo
Published: April 2011

The pretreatment of concrete rapid chloride migration coefficient (RCM) method in different standard is different in China. However the influence of pretreatment on the experimental result is uncertain, which leads to poor comparability about the results between different standards and trouble in evaluating the durability of concrete structures. The influence of the pretreatment on the chloride diffusion coefficient was studied by contrastive method. On the base of the results a suitable pretreatment of RCM method was proposed. The results are as followings: (1) the influence of pretreatment on the chloride migration coefficient of concrete with 0.45 W/B is insignificant. The influence of pretreatment on the chloride migration coefficient of concrete with other W/B is significant, and the influence increase with the lower w/b.; (2) the chloride diffusion coefficient will increase after the ultrasonic bath and vacuum saturation, and the influence of the ultrasonic bath is larger. Considering the judgment to the durability of structure, the ultrasonic bath and the vacuum saturation are suggested to be used; (3) on the condition of the same anode and cathode solution, the chloride diffusion coefficient in accordance with JTG / T B07-01-2006 standard is usually higher than that in accordance with GB/T50082-2009 standard; (4) the relationship of the chloride diffusion coefficient between mortar and concrete specimens is uncertain under different proportion and curing system, so the mortar specimens can not replace the concrete specimens for the RCM method.