bluuebunny/crossref_metadata_2025 huggingface dataset:
A Improved Chan Algorithm Basing on Particle Filtering in NLOS Environment
Authors: Wang Zhen Qiang , Zhu Yi Sheng , Liu Nan
Published: March 2011

In the wireless positioning issue basing on TOA/TDOA, NLOS makes a great impact on the positioning accuracy. This paper presents a particle filtering based improved Chan Algorithm. Considering the case of multiple base stations, in the first step we use Chan algorithm to get the initial location estimation basing on the information provided by the base stations which are divided into subgroups. In the second step, we calculate the contributions of these estimated locations, and then use these contributions in the particle filtering framework to get the MAP of the location. Experimental results show that the improved algorithm can suppress the effect of the NLOS and can get better location estimation than the basic algorithm.
Crush Behavior of Corrugated Cores Sandwich Panels
Authors: Zhang Yan Chang , Zhang Shi Lian , Wang Zi Li
Published: March 2011

The out-of-plane quasi-static compressive behavior of four types of corrugated cores (V-type, U-type, X-type and Y-type core) has been investigated by experiment and FE simulations. By transient dynamic finite element analysis code MSC.Dytran numerical simulations were performed for calculating crushing forces, deformation mode and energy absorption. The FE simulations predict the crush behavior of cores with reasonable accuracy and provide the whole progressive buckling process and deformation modes. Experiment and simulation indicate that the U-type core, V-type core and X-type core structures show excellent crushing resistance performance and energy absorption characteristic. The crush performance of the Y-type core structures is relatively poor because of bending mode.
Study on Key Technique of Reconfigurable CNC System
Authors: Zhu Gao Feng , Zhang Yan Lei
Published: March 2011

FPGA has been used in CNC system, it can achieve the impulse, the count, arithmetical operation, I/O interface and so on, and therefore it can greatly simplify the design of control circuit. In this special structure mechanism, the processing and monitoring of CNC system based on FPGA instead of traditional MCU is implemented. The overall structure of reconfigurable CNC system is described, meanwhile, the DDA accurate interpolation and the control circuit of stepper motor is emphatically solved through Using the FPGA. With the result of several experiments, the performance of the CNC system is improved, reconfiguration is strengthened, besides, the peripheral interface devices and cost is greatly reduced.
Study on Simulation Signals of Blasting Seismic Waves Based on Technology of Wavelet Analysis
Authors: Wei Hai Xia
Published: March 2011

Based on technology of multi-resolution wavelet analysis, a simulating method for velocity signals of blasting seismic waves was put forward. The simulation signals not only represent main characteristic parameters of blasting seismic waves, but also consider action of several dominant frequencies of sub-bands with large energy proportion. It is indicated by comparing structural dynamic response to simulation signals and measured signals that the method for simulating blasting seismic signals based on technology of wavelet analysis has great practical value and feasibility.
Structural Optimization of an Inertially Stabilized Platform for Aerial Remote Sensing Systems
Authors: Zhou Xiang Yang , Yu Rui Xia , Li Da Peng , Li Jian Ping
Published: March 2011

The purpose of this paper is to study the methodology on structural optimization of inertially stabilized platform (ISP). It is difficult for the ISP structure design since lots of objects are required and many of them are conflicted each other, hence structural optimization should be carried out to seek a compromise between theses contradictions, such as high stiffness and light weight, high ratio of payload to mass and small size, etc. In this paper, first of all, an optimal configuration of 3-axis gimbals assembly is determined on the basis of analysis on the operating environment; and then, an approving structure is eventually obtained with the help of 3D CAD modeling and FEA. The structure is compact as well as lightweight. FEA results show that its strength and stiffness are both satisfied with the requirements.
Reasons and Prevention Measures of Crack at the Bottom of the Extruded Magnesium Alloy Tube
Authors: Meng Mu , Zhang Zhi Min , Yang Yong Biao
Published: March 2011

Microstructure observation by optical microscope and numerical simulation by MSC software were performed to study the reason of ring crack at the bottom of the extruded magnesium alloy tube. On this basis, the effective protective measures were proposed by numerical simulation analysis. The result shows that: there is a significant difference between the direction of backward extrusion metal flow and the direction of the original metal flow direction. Therefore, the plastic deformation is difficult, and then the crack initiates owing to severe stress concentration. Through simulation analysis, it is found that both increasing the bottom thickness and changing the bottom position could effectively prevent the crack.
Synthesis and Characterization of Ti, Fe-Doped Mullite-I
Authors: Tong Lin Xin , Li Jin Hong , Cao Jian
Published: March 2011

A series of gels with 3Al2O3•2SiO2 were prepared by Sol-gel method and heated at several temperatures for 2 h to synthesize Ti, Fe-doped mullite. The powers were characterized by differential thermal analysis (DSC-TG) and X-ray powder diffraction (XRD). Phase separation was promoted by doping both TiO2 and Fe2O3; with increasing the amount of dopant ions the formation temperature of Si-Al spinel decreased and the formation temperature of mullite increased by TiO2 doping but decreased by Fe2O3 doping. The formation temperature of pure mullite was about 1250-1350 °C.
Pressure Regularity Study of Three Soft Complex Coal Caving Coal Face
Authors: Ma Nian Jie , Zhao Guo Dong , Ju Chun Lei , Li Chong , Dong Xiang Zhong
Published: March 2011

In order to grasp the movement rules of three soft coal caving complex working plane strata and stoping space surrounding rock and hydraulic support interactions relationship, improve the management of mining roof, to do research about the distribution rule of caused abutment pressure and shield support of initial supporting force, the work resistance and adaptability of coal seam. The first coalface of testing mine 1301 mining coal gangue is clip three soft and thick coal seam mining, adopt fully mechanized caving technology, choose ZF6400/17/32 type support screen type top coal caving hydraulic to support working face roof support, in order to provide better services for safe production in the working face, especially study on related factors affecting the observational of working mine pressure.
Effects of Technological Parameters on the Tensile Properties of GF/PET Hybrid Thermoplastic Composite
Authors: Tian Wei , Li Yan Qing , Feng Zhao Hang , Zhu Cheng Yan
Published: March 2011

The preforms were woven by the co-yarns which were consisted of GF, PP and PET. Then the co-yarns were manufactured into hybrid thermoplastic composites. The parameters of the forming process were studied by analyzing the tensile properties of the composites. The results show that the composite holds the best tensile properties when the pressure is 5MPa, the packing temperature is 190°C, and the holding time is 30 min. The existing of a second pressure of 10 MPa at 150°C for 3 min will help to improve the capacity of the load supporting for the GF/PET thermoplastic composites
Research on Mine Pressure Behave Law in Mining of Face under the Coal Pillar
Authors: Shi Wei , Liu Hong Tao , Liang Cui , Jia Hou Sheng
Published: March 2011

When mining close-distance seams with downlink mining, in order to benefit roof maintenance and management, the decoration of lower seam roadways should try to avoid the area affected by pillar concentrated stress , using inside cross decorationg; In order to improve the recovery rate of resources, the size of protection pillar can’t be too big, when mining under pillar of upper layer and mining in pillar of upper layer with crossing. The whole lower face or some phase located under the influence of upper coal concentration stress, give roadways and working face roof maintenance a lot of difficulties. Then it appeared the conflict between security and economy, to solve this problem, we must return to the correct understanding of mine pressure behave law. In the paper, through the investigation of the typical dozen example in mining of face the coal pillar in China, to get its regular pattern of mine pressure behave, in similar conditions mining, there will be important reference and guidance.
Simulation of Numerical Test of Concrete Mechanical Properties Base on Numerical Manifold Method
Authors: Zhao Yan , Zhang Guo Xin , Ru Song Nan , Chai Fu Xin
Published: March 2011

In order to reflect the heterogeneity of concrete at mesoscopic level and simulate the mechanics response from the mesoscopic to macroscopical in the course of load, the random aggregate model according to the Monte Carlo method and Fuller Graded Formula is carried out based on the assumption that the concrete is a multi-phases composite material composed of matrix, and the material parameters are defined based on the test. In this paper, the Numerical Manifold Method introduced not only can correctly simulate stress, deformation and failure of concrete, but can simulate propagation of multi-cracks in the concrete, and failure plane growth can be searched by stress results automatically, so it can simulate the kind high discontinuous problem very well. On this basis, NMM is adopted to simulate the tests on concrete mechanical performance. The creation, propagation and fracture process of cracks in compression of concrete are present. The computational results are in good agreement with the experimental data.
Feature Selection Based on GA and PNN
Authors: Hao Min , Ma Shuo Shi , Hao Xiao Dong , Ma Li Li , Wang Li Juan
Published: March 2011

A new image feature selection method with the combination of Genetic Algorithm(GA) and Probabilistic Neural Network(PNN) is proposed and applied to potato shape feature selection and classification. The classifier selecting principle is investigated by combining with the genetic algorithm. A new feature selection method based on GA and PNN is put forward firstly. Comprehensively considering the factor of classification accuracy,selected feature number and the impact of the two factors, a new fitness function is proposed. The initial Zernike moments parameters of potatoes are optimized using improved genetic algorithm, and nineteen Zernike moments are extracted to form the shape feature. The shape detection accuracy can reach 93% and 100% respectively for the perfect and malformation potatoes. The tests indicate that the fitness function and feature selection method can be used for searching the best feature combination.
Analyze on the Mechanical Properties of Stitched Composites
Authors: Chang Tao
Published: March 2011

As the most potential member in the textile composite material, stitched textile composites have already been paid a lot attention. By the simply technology form and relatively low cost, stitched composites had attracted many domestic and foreign researchers, and were gradually used in various engineering practice. This paper using 3D micro-finite element method researches the mechanical behavior and performance of stitched composites, establishing a 3D micro-finite element model for the stitched composites under the improved locking suture way. Through analysis, it shows that each material’s stress distribution characteristics under external loading and finds that the results of this paper’s finite element data results matching well with previous studies’ results, proving the feasibility of this study, so it can be used for forecasting the mechanical properties of a variety of practical stitched composites.
Delaunay Graph Based Path Planning of Dynamic Obstacle Avoidance Method for Mobile
Authors: Dong Hui Ying , Song Yang , Zhao Yu
Published: March 2011

This paper is about dynamic obstacle avoidance. Delaunay Graph is used for modeling the working space, an approximate shortest path of mobile robot is determined by using floyd algorithm. Path can be found easily with genetic algorithm. Then genetic algorithm is used for obtaining the optimum path. It may meet which dynamic obstacle when robot follows optimum path. so it should avoid it. Results of simulation show that this path planning method is simple and realized easily.
Research on the Buffer Zones of Cultural Heritages with the Theory of Soliton
Authors: Li Wen Yong , Shi Kai , Liu Chun Qiong , Hu Wen Yong
Published: March 2011

Cultural heritage, as a special cultural resource bearing information of human history and, passing on human culture, are not reproducible and movable. Scientifically identifying the scope of its buffer zone is the key to the sustainable development of culture relics. Development and Application of soliton provide us a train of thought for demarcating the buffer zones of cultural heritages. On the basis of soliton theory, isentropic trait, the authors analyze the scientific signification of buffer zones and the methods to demarcate the buffer zones theoretically.
Dynamic Compressive Behavior of Concrete at High Temperatures
Authors: Liu Chuan Xiong , Li Yu Long , Hou Bing , Guo Wei Guo , Zou Jin Long
Published: March 2011

For investigating the effect of temperature on the dynamic properties of concrete material, tests for cylindrical concrete specimens at 23°C ~ 800°C were carried out by using Split Hopkinson Pressure Bar (SHPB) apparatus, and the strain rates ranged from 30/s to 220/s. Effects of temperature and strain-rate on the dynamic behavior of concrete were analyzed. The results show that: above 4000C, the dynamic compressive strength of concrete decreases with increasing temperature, and the enhancements of strain-rates on the compressive strength of concrete depend significantly on temperatures. Moreover, both strain-rate and temperature can enhance the peak strain of concrete.
An Innovation Ability Characterization Study on a High-Level Professional Tennis Coach in China
Authors: Ke Yong , Liu Yuan Hai
Published: March 2011

This paper adopts documentary data method, questionnaire method, interviewing method and mathematical statistics method and proceeds from the respect of the cognition in the innovation ability of an coach from the high-level professional tennis athletes, in order to research into an innovation ability characterization of an ideal coach in athletes’ sight as well as differences in understanding the innovation ability of an ideal coach from the different groups of athletes, such as the ones of different genders, ages, degrees of education and sports levels. Comparing the innovation ability of the current coaches with that of ideal coaches, this paper reveals similarities and differences of the innovation ability of the current coaches and the ideal ones, in the hope of affording complete, sufficient and scientific theory evidence to further improve training ability of professional tennis coaches, to promote the scientific tennis training, and to facilitate the fast growth of tennis competitiveness.
The Current Situation and Countermeasures of Online References Recording about Sports Core Academic Journals
Authors: Wang Xiang Fei , Zhou Xian Jiang
Published: March 2011

Through analyzing the recording format of online references in our Chinese sports core academic journals, we find that its percentage of citing online references is relative low compared with other academic journals. The main problems existing during the process of recording are: the entries of recording are not complete, the written form is not standard, and the recording of website is not exhaustive, and so on. On the basis of that analysis, we propose the countermeasures: we should attach great importance to the recording standardization of online references and hold principles well in citing online references to strive to record online reference correctly.
The Practical and Innovative Research of College Taiji Softball
Authors: Guo Qing Sheng
Published: March 2011

Through the innovative research of college Taiji softball repertoire, this article aims to clarify the basic principles of college Taiji softball’s innovative methods, thus to provide theories and approaches to the innovative research of Physical Education programs. Besides, this essay also provides theoretical basis for innovative practice of Taiji softball and also enriches the content of national fitness activities. The creation of Taiji softball repertoire is a complex and integrated embodiment and the creative capability influnced by many factors, which includes the teachers’ physical experience, skill, theoretical knowledge, ways to think and analyze, capability to integrate and solve all the problems. In the daily teaching, training, communicative competitions and life, collecting and processing the movement materials are the prerequisite and basis. For these are beneficial to master the creative principles, get familiar with creative approaches, enhance the level of appreciating music and strengthen practical competence.
A Research on Coping Styles of College PE Majors
Authors: Wang Jian Qiang
Published: March 2011

Coping problem is closely related to mental adapt and mental health. Coping style is an important mediator in physical normal college students’ mental stress, which affects students’ mental health. Based on a lot of documents, specialist interviews and questionnaire physical normal college students’ coping style features. Discuss physical normal college students’ methods of coping style in problem of life and study.
Study on the Method of Designing Sound Absorption Model by Multiple-Layer Structures each Layer’s Natural Impedance
Authors: Zhou Sui Hua , Zhang Wen Cheng , Jiang An Lin
Published: March 2011

The laconic calculating formulae of arbitrary multiple-layer model’s acoustic characteristics are introduced with sound transmission theoretics in multilayer mediums. Taking properties of viscoelastic material in account, the sound absorption characteristics of multiple-layer model covered with viscoelastic material underwater are calculated using formulae deduced. By numerical analysis, the relation between absorption model and material parameters is simulated and the effect of proportion among layers’ natural impedance on acoustic characteristics of sound absorption model is analyzed. Then the method of designing sound absorption model by multiple-layer structures each layer natural impedance is studied. The result is of significance to devising sound absorption material and model.
Mechanical Properties and Micromorphologies of Methyl- Silsesquioxane/Cyanate Ester Resin Organic-Inorganic Hybrids
Authors: Zhang Zeng Ping , Pei Jian Zhong , Chen Shuan Fa , Wen Yong , Du Hong Zhao
Published: March 2011

A kind of nonfunctional oligomeric silsesquioxane (SSQ), methylsilsesquioxane (Me-SSQ), was used to modify cyanate ester resin (CE) in this paper. First, Me-SSQ was synthesized by the hydrolysis and condensation of methyltriethoxysilane. Then a series of Me-SSQ/CE hybrids containing 0wt%, 1wt%, 5wt%, 10wt% and 20wt% of Me-SSQ were prepared. Curing reactivity of the hybrid materials was studied by differential scanning calorimetry (DSC). Mechanical properties of the Me-SSQ/CE hybrids were studied systematically. Impact strength of the Me-SSQ/CE hybrids reaches its maximum value when Me-SSQ content is 5wt%. However, the flexural strength reaches the maximum value when Me-SSQ content is 1wt%. SEM images accord well with the mechanical properties. It is concluded that appropriate amount of Me-SSQ is favorable to improve the mechanical properties of Me-SSQ/CE hybrid materials.
Theoretical Prediction and Experimental Research on the Tensile Strength of GF-TPU Composite
Authors: He Jian Yun , Ming Ma , Wang Ke Jian
Published: March 2011

Based on fiber length, fiber orientation distribution, ratio of length to diameter and fiber-matrix interface, the theoretic prediction equation of tensile strength has been established for glass fiber/thermoplastic polyurethane (GF-TPU) composite. The relationship between the structure and tensile strength of GF-TPU composite was theoretically and experimentally studied. The results showed that the predicted tensile strength fits the test results quite well.
Influence of RE/Mn (RE= La, Nd and Gd) Ratios on the Infrared Absorption and Emission Properties of Co-Zn Ferrites
Authors: Zhang Ying , Wen Di Jiang
Published: March 2011

The RE/Mn co-doped Co-Zn ferrites were prepared by the ceramic method. Infrared absorption and emission properties were obtained by investigating those ferrites. The IR spectra in the range from 400 to 1200 cm-1 were observed. Mainly, three bands were investigated. The high-frequency bands and low-frequency bands were assigned to the tetrahedral and octahedral complexes, respectively. The intensity of all the bands is found to increase while a decrease in broadness, which is explained on the cation distribution in the tetrahedral and octahedral sites were modified by RE/Mn addition. The Mn substitutes the Fe3+ and enters into the octahedral sites; while the partial RE3+ ions are apt to diffuse to the grain boundaries and others enter into the spinel lattice .This can be explained on the basis of ionic radii and ratios of the substituted cation. The results indicate that IR emissivity seems to be increasing with RE/Mn ratio within 8-14 μm wavebands. The maximum infrared emissivity is 0.968 when La/Mn ratio of 0.20 within 8-14 μm wavebands.
Study on Job Shop Scheduling Optimization with Multi-Objective
Authors: Ze Tao , Liang Di , Qun Zhou
Published: March 2011

A new multi-objective scheduling method based on the GA is proposed to the job-shop scheduling problem (JSP) constrained by machines, workers. Function objectives of the proposed method are to minimize the completion time, the maximum load of machines and the total expense of machines and workers. Firstly, the mathematical model is constructed. Then, on the basis of the mathematical model, the genetic algorithm (GA) based on Pareto is applied, and an optimal or suboptimal scheduling plan can be obtained. The optimal solutions are not unique due to the multi-objective of JSP. Finally, a scheduling example is employed to illustrate that the proposed method could solve multi-objective job shop scheduling problem effectively.
Synthesis and Characterization of Hierarchical Zeolite with High Mechanical Stability
Authors: Ling Xu , Zong Rui Liu , Qiu Bin Kan
Published: March 2011

A hierarchical zeolite was synthesized by self-assembly of ZSM-5 nano-crystals colloid and polystyrene spheres coated with cationic poly (diallyldimethylammonium chloride). The colloidial ZSM-5 nano-crystals were first bound onto the polyelectrolyte-modified PS by electrostatic attraction, followed by centrifugation to form PS/ZSM-5 close-packed composite. After being dried and calcined to remove the organic components, the hierarchical zeolite was obtained. The X-ray diffraction, scanning electron microscopy, transition electron microscopy and N2 adsorp-tion-desorption techniques were employed to characterize the hierarchical zeolite. The results showed that the material prepared by this method was well crystallized and possessed uniform ma-cropores interconnected in three dimensions through windows. Furthermore, the hierarchical zeolite was rather mechanically stable.
Determining Modulus of Elasticity of Ancient Structural Timber
Authors: Zhang Hou Jiang , Zhu Lei , Sun Yan Liang , Wang Xi Ping , Yan Hai Cheng
Published: March 2011

During maintenance of ancient timber architectures, it is important to determine mechanical properties of the wood component materials non-destructively and effectively, so that degraded members may be replaced or repaired to avoid structural failure. Experimental materials are four larch (Larix principis-rupprechtii Mayr.) components, which were taken down from the drum-tower of Zhengjue Temple of Yuanmingyuan (Old Summer Palace), Beijing, China. The larch components were cut into standard specimens first, and then stress wave transmission times, resistograph and densities were tested. Product of resitograph and stress wave speed squared is defined as modulus of stress-resistograph. Comparing with the modulus of elasticity (MOE) of the specimens tested by the traditional bending test method, it is found that there is a linear relationships between the modulus of stress-resistograph and modulus of elasticity (MOE), and the correlation coefficients are 0.7111. In order to better evaluate the modulus of elasticity (MOE) with the modulus of stress-resistograph, 95% confidence regression lines are suggested to be used for the future calculation.
Scraper Conveyor Dynamic Modeling and Simulation
Authors: Zhang Dong Sheng , Liu Xiao Hong , Shi Jian Guo , Mao Jun , Li Zhong
Published: March 2011

Modeled nonlinearity, time-varying, dynamic coupling finite element model of scraper conveyor according to its actual working condition in the mining, studied the transmission mechanism of bulk material power and its parameters test methods，constructed the shape function of scraper conveyor circuitry, realized the computer automatic modeling, by the example carried on digital simulation of all of working condition such as starting, freely stoppage, abnormal load, chains blocked, the difference of chain’s pitch and the chain wheel polygon effect, and so on.
Blast Loads on Concrete Bridges
Authors: Hu Zhi Jian , Liu Chao
Published: March 2011

Nowadays few current studies on blast effects are executed with real bridge structures for economic and social reasons. This paper analyzes the blast loadings on concrete bridges and offers five characteristics: uncertainty, significant structural response, mechanic differences, rapid overpressure decay, and confinement effects. Then with the further study for blast loads fundamentals and real bridge inspection, the damage forms for concrete bridges under blast loadings have been obtained, i.e. localized damage are the main structural damages and fragmentation loads can be neglected when explosions detonated above deck. Furthermore, due to the collapse or fallen of the structural components or segments secondary damages, like collisions and restraining blocks destruction, must be kept an eye on.
Effect of Calcium Modification on the Microstructure and Properties of High Speed Steel
Authors: Zhou Xue Feng , Yin Xiao Yan , Fang Feng , Jiang Jian Qing
Published: March 2011

The present work has investigated the influence of calcium on the microstructure and properties of AISI M2 high speed steels. The results show that the as-cast structure consists of the iron matrix and networks of M2C eutectic carbides, which are greatly refined in the ingot modified by calcium. Meanwhile, the morphology of M2C evolves from the plate-like shape into the fibrous one. Compared with the plate-like M2C, the fibrous M2C is less stable at high temperatures, which promotes the spheroidization and refinement of carbides. Therefore, M2 steels modified by calcium obtain higher hardness and red-hardness after heat treatment than those without the addition of calcium.
Relation Expression and System Design for District Collaborative Design
Authors: Ma Jun
Published: March 2011

The district collaborative design is an advanced design organization mode. The problem of definition and expression of correlation in collaborative design is aimed. The organization characteristics are analyzed based on district collaborative design space. The connection relationship acyclic graph which includes connection semantics is achieved and the relationship specialty and connection mode are explained. The algorithm is proposed to solve correlation for district collaborative design by use of correlation information model, and the correlation management model based on PDM is illustrated. Finally, a case study is conducted to prove these theory and method.
Research on Hierarchical Evaluation of Information System Agility
Authors: Yi Chao , Liao Hong Zhi , Zhou Wei , Wu Jian De
Published: March 2011

In order to exist and develop in an unpredictable and rapidly changing surroundings, it is necessary for enterprise to have an agile information systems to support its success. An agile information system is the one can reconstruct itself and adapt quickly to it’s environments. The article will begin with the focus on one more properties of information system agility, explain its definition, build its evaluating indicator system, provide the hierarchical evaluation model of information system agility, and describe the evaluation process and mathematical method. Finally, by using an example, the practicability and validity of the evaluation model is proved, comprehensive and scientific evaluation of information system agility is achieved.
Mechanical Properties of Cement-Free Bauxite Based Castables Bonded by Hydratable Alumina
Authors: Ding Yu , Wang Bing Jun , Liu Kai Qi
Published: March 2011

Cement-free castables bonded by hydratable alumina with or without SiO2 fine powder were prepared with bauxite as main raw materials. The mechanism of castables’ mechanical performance, as sintering temperature increased, was investigated. The results showed that the strength of these castables decreased at relatively low temperature because of the hydrates de-watering and the transforming of crystal type of Al2O3, while the strength improved at high temperature. And the addition of SiO2 fine powder can improve the castables’ strength and advance the temperature point, from which castables’ strength started to raise up.
Water Absorbing and Releasing of Lightweight Aggregate and its Influence on Frost-Resistance of Combined Aggregate Concrete
Authors: Gao Li Xiong , Kong Li Juan , Ge Yong
Published: March 2011

Water absorbing and releasing property of lightweight aggregate (LWA) in concrete and its influence on microstructure of interfacial zone as well as frost-resistance of combined aggregate prepared with different water absorption LWA and w/b ratios were investigated. The results show that, as for concrete with low w/b ratio, the 28d frost-resistance of concrete prepared with high water absorption LWA is worse, however with the increase of curing age, the 90d frost-resistance of concrete improves obviously, which is due to the water releasing of LWA that leads to the recovery of its air entraining effect as well as the densification and thicken of interfacial zone. So the LWA with moderate water absorption should be selected to prepare the low w/b ratio concrete. As for concrete with high w/b ratio, the frost-resistance of concrete prepared with low water absorption LWA is the best. This is account for the dense shell of ceramsite that could reduce the soakage from loose cement paste under frozen pressure.
Research on Main Performance and Impact Factor of Flakeboard through the Method of Partial Least Square Regression
Authors: Zhao Lei , Xiao Sheng Ling
Published: March 2011

In this research, the wood residues of mixed birch and larix gmelini rupr are used as the bulk material, and phenolic resin glue and moso bamboo slice as reinforcing material to make flakeboard through three-phase pressure process. Data Processing System (DPS) is used to analyze glue volume, density and other technical parameters’ impact on the performance of wood composite product, establish multiple linear regressive mathematic models, compare and optimize experiment plan, find out and verify the best technical conditions. The result shows that the overall objective function will reach 6.908 when glue volume is 8.107%, density 0.870 g/cm3, thickness 2.015cm and moisture content of 9.799%.
Comparative Study on the Application of Naphthalene Water-Reducing Agent and Polycarboxylate Water-Reducing Agent in High-Performance Concrete
Authors: Gao Lin , Shi Yan , Xu Guo Qiang
Published: March 2011

We respectively conduct performance contrast test on cement paste, cement mortar, and high-performance concrete which have been added naphthalene water-reducing agent and polycarboxylate water-reducing agent. Studies show that naphthalene water-reducing agent can better improve the performance of concrete and increase the fluidity of concrete to ensure its keeping slump. Meanwhile, the age strength and the growth rate of strength of concrete with mixing polycarboxylate water-reducing agent has been significantly improved than those of naphthalene water-reducing agent, which can better meet the strength requirements of concrete and get a bright application prospect that naphthalene water-reducing agent can not reach.
All-Optical Poling Properties of the Host-Guest Adulterant Thin-Films
Authors: Gao Xue Xi , Wang Wen Jun , Liu Yun Long , Li Yun
Published: March 2011

The poling conditions were studied in AOP process by second harmonic generation (SHG) for host-guest adulterant thin-films. The guest was 4’-Nitro-4-dimethylaminoazobenzene and host was PMMA. The experimental results showed that the optimal poling temperature was about room temperature, the optimal ratio of light intensity of fundamental signal (ω) and its second harmonic signal (2ω) during AOP was approximately 100, the thin films had the same rule that the saturated value of SHG depended on the ratio. In addition, we obtained a suitable thickness around 2200nm that the stronger SHG after poling was generated.
Rheological Behavior and Mechanical Properties of PVC/V-POSS Nanocomposites
Authors: Gao Jun Gang , Du Yong Gang , Li Xing
Published: March 2011

The poly(vinylchloride) (PVC) nanocomposite was prepared by melt mixed of PVC with polyhedral oligomeric silsesquioxanes containing vinyl group (V-POSS). The rheological behavior of V-POSS/PVC nanocomposites was investigated by torque rheometer and capillary rheometer. The influences of composition of blends, shear rate, shear stress on melt apparent viscosity and non-Newtonian index (n) were discussed. The dynamic mechanical properties, mechanical properties and morphology were determined. The result shows that the plastic time of nanocomposites decreases while melt viscosity increases with increasing V-POSS content. V-POSS has a good compatibility with PVC. The nanocomposites have better impact strength with increasing V-POSS content. V-POSS can use as process aid and impact aid at appropriate contents.
On the Monotone Matrices over Distributive Lattices
Authors: Jiang Jing , Shu Lan , Tian Xin An
Published: March 2011

Since lattice matrices are useful tools in various domains like cluster analysis, computer network, traffic control, logistics and so on, the study of the properties of lattice matrices is valuable. A lattice matrix is called monotone if is transitive or is monotone increasing. In this paper, the transitivity of powers and the properties of a transitive lattice matrix are studied. Also, the proper- tyes of a monotone increasing lattice matrix are considered.
Fracture Behavior of a Brittle Coating on an Elastic Substrate under Residual Stress
Authors: Yang Ban Quan , Li Peng
Published: March 2011

The fracture behavior of a brittle coating on an elastic substrate under residual stress is investigated. Using a mechanical model, the analytical solutions for the distribution laws of the tensile stress developed in the coating, the shear stress developed along the interface and the relationship between the crack density of the coating and the residual stress can be obtained. The analytic relationship between the crack density and the residual stress can also be taken as a new expression to estimate the magnitude of the residual stress. A numerical example is presented to show how the crack density varies versus the residual stress.
Delay-Probability-Distribution-Dependent Stability Analysis for Stochastic Neural Networks with Mixed Time-Varying Delays: The Discrete-Time Case
Authors: Zhou Xia , Zhong Shou Ming
Published: March 2011

The problem of delay-probability-distribution-dependent stability analysis for a class of discrete-time stochastic delayed neural networks (DSNNs) with mixed time delays is investigated. Here the mixed time delays are assumed to be discrete and distributed time delays and the uncertainties are assumed to be time varying norm bounded parameter uncertainties. The information of the probability distribution of the time-varying delay is considered and transformed into parameter matrices of the transferred DSNN model, in which the time-varying delay is characterized by introducing a Bernoulli stochastic variable. By constructing a new augmented Lyapunov-Krasovskii functional and introducing some new analysis techniques, a novel delay-probability-distribution-dependent stable criterion for the DSNN to be stable in the mean square sense are derived. These criteria are formulated in the forms of linear matrix inequalities.
Comparison Research on Determination of Contact Loads with Finite Element Method and Mode Superposition Method
Authors: Yang Yong Qiang , Xie Li Li
Published: March 2011

In order to solve the problem of collision in engineering field, the dynamic equation of collision system was established based on FEM(finite element method) and contact element model. The present method can account for the influence of the nonlinear contact stiffness as well as the energy loss during collision process. Collision had been simulated using FEM and MSM(mode superposition method) separately with various contact stiffness, sphere masses and impact velocities. The results indicate that FEM can be used to solve the problem of collision. The two groups of time history curves of contact load have almost the same shape. Compared with the results by MSM, collision durations are relatively decreased by about 7%, and difference of peak value is no more than 4%. The method can be used for collision between two complex structures with nonlinear reaction. So, it has a wider application to simulation of collision damage in engineering field.
Modelling Methods and Error Analysis of Deformable and Non-Deformable Real Particles
Authors: Du Xin , Zeng Ya Wu , Gao Rui , Yan Jing
Published: March 2011

In order to realize the real particles’ irregular shape representations, which considering the real particles’ deformable and non-deformable characteristic. Firstly, we extracted the three dimensional coordinate information of real ballasts by dealing with ballast’s X-ray tomography imagines. Secondly, considering the deformable and non-deformable characteristic, two mdoelling methods were introduced based on real particles’ three dimensional coordinates. The deformable particle models are generated by non-overlapping combined basic-spheres, while the generation process is controlled by the extraction accuracy of real particles’ three dimensional coordinates. The non-deformable particle models are generated by overlapping combined basic-spheres, while the generate process is controlled by two parameters. Both two modelling method are initial conditions unrelated, and the model generation process can be repeatedly. Finally, in the condition that two methods’ basic-sphere numbers are approximately equally, the conclusion that non-deformable modelling method represents the real particles’ shape more efficiently can be drawn by error analysis.
Effect of Melt Overheating History on the Microstructure of Ni-Base Single Crystal Superalloy
Authors: Zou M.M. , Zhang Jun , Li B. , Zhu L.J. , Liu L. , Fu H.Z.
Published: March 2011

With the unchanged thermal gradient and withdrawal speed, the effect of melt overheating history on the microstructure of Ni-base single crystal superalloy is investigated. The results show that the dendrite structure and γ' phase in interdendritic area is obviously refined when overheating temperature increased from 1500 °C to 1640 °C and then to 1780 °C. However, the microstructure is coarsen with the holding time is increased from 30 min to 45min and then to 60min when melt is overheated at 1780 for 30min.
Data Analysis and Forecast for Aircraft Structure Impact Damage Based on GP Symbolic Fitting Method
Authors: Hou Man Yi , Fan Hui Lin , Zhu Wu Lin
Published: March 2011

In order to research the aircraft impact damage, one symbolic fitting method for analyzing and forecasting the damage data is proposed based on genetic programming (GP). The method can be used to forecast the impact damage by recognizing the rule in some groups of actual data including impact parameters and damage hole size. The principle of GP symbolic fitting method is briefly introduced. The fitting model is created with some sample data respectively for training and testing from Sorenson experiential equation. The computation with Matlab program indicates the model has a good performance to fit and forecast the damage data with avoiding the noise. The application of GP symbolic fitting method can help to decrease the times of fire experiments. Since the method can recognize the complicated nonlinear relationship between the impact parameters and damage data, it is more applicable than theoretical analysis and experiential equation to forecast the aircraft impact damage.
A Study on Out-of-Plane Compressive Properties of Metal Honeycombs by Numerical Simulation
Authors: Li Meng , Liu Rong Qiang , Guo Hong Wei , Deng Zong Quan
Published: March 2011

To provide theoretical basis for metal honeycombs used as buffering and crashworthy structures, the effect of the cell length and foil thickness on compressive properties of metal honeycombs is investigated by numerical simulation. Numerical results are well consistent with the corresponding experimental results. The numerical results show that metal honeycombs have cyclic buckling when loaded in out-of-plane direction. The thicker the foil is or the shorter the cell length is, the higher the plastic collapse stress is and the plastic collapse stress is much sensitive when cell length is short. The numerical simulation used in this paper can well predict the crush behavior. Single and doubled foil portions of cell walls are also accounted in the FE model. The results demonstrate that the method is effective which can be used in optimization design of buffers.
Risk Assessment of Reinforced Concrete Structure Attacked by Chloride
Authors: Sookoomjariyapong Chongsin , Vongchavalitkul Sanguan , Sayamipuk Sun
Published: March 2011

The deterioration of reinforced concrete (RC) structure due to chloride attack plays an important role in the reduction of structure strength. Consequently, the actual condition of structure is an essential investigation for management planning in concrete structure which is attacked by chloride. In this paper, the proposed assessment bases on the risk management and the reliability theory presents in risk index (RI) of structure. The reinforced concrete building under the marine environment was an illustrative example for risk evaluation. It was found that the risk index of structure equaled to 20, it implied that the structural condition encountered with extreme risk due to chloride attack and must be rehabilitated urgently. As analysis results, the risk assessment is relation to the actual condition of structure. This assessment can be used as a guideline tool for structural engineering to assess the concrete structure attacked by chloride.
The Effect of Water-Cement Ratio and Curing Age on the Strength of Recycled Concrete
Authors: Zhang Xue Bing , Kuang Chen Gang , Fang Zhi
Published: March 2011

The effect of water-cement ratio and curing age on the strength of recycled concrete was studied by experiment with the combination of the recycled coarse aggregate adding natural sand. The results showed that with the increase of curing age, the greater the water-cement ratio is, the smaller the strength growth rate is; the smaller the water-cement ratio is, the greater the strength growth rate is. There is a relatively larger increase in the growth rate of 90d strength than 28d’, which is significantly higher than that of the ordinary concrete. The linear relationship between water-cement ratio and strength of recycled concrete is worse than that of ordinary concrete. Under the same water-cement ratio and curing age, the strength of recycled concrete is lower than that of ordinary concrete, and the empirical formulas between the strength of 28d and 7d, 90d and 28d were obtained.
Theoretical Study of an Axial Pumping Baffle Seal for Reactor Coolant Pumps
Authors: Liu Xin , Peng Xu Dong , Meng Xiang Kai
Published: March 2011

Based on the principle of a screw seal, a new type of seal consisting of a series of screw seals was developed and named as an axial pumping baffle seal. A theoretical analysis model was presented for such a seal which was developed to be used in nuclear coolant pumps. The feasibility of sealing high-pressure medium for such a seal had been proved. The variation of leakage rate and pressure distribution between a tooth and a sleeve with the number of seal stages and the geometrical parameters of screws was studied. The sealing mechanism was presented. The results showed that such a new seal maybe replace the first stage seal of a series mechanical seal used in a nuclear pump. When the number of screw seals is about 9, the reliability is ensured by the cooperation of the “attack” of the screw seal and the “defense” of the 180° sharp back bend.
Case Study on CDIO-Based Engineering Education Mode through College-Industry Linkages
Authors: Ye Wei Wei , Lu Wu
Published: March 2011

the paper puts forward the CDIO-based engineering education mode under college-industry linkage on the basis of the experiences of many Chinese technical schools in this regard. It also elaborates on the syllabus, teaching, laboratory and evaluation of the mode. At last, through case study of college-industry linkage of China’s plastic machinery industry, it proves that the mode is effective to cultivate engineering talents that are most needed in China in a time when the engineering resources are less than needed. The mode can serve as a reference for many developing countries that are sandwiched between the tough choices of cultivating specialists of certain filed or generalists with applicability abroad.
A Design of Amplifying Circuit Based on Pt Resistance Strain Pressure Sensor
Authors: Shi Yao Hong , Zhao Zhan , Fang Zhen , Geng Dao Qu , Xuan Yun Dong
Published: March 2011

This topic takes the miniature Pt resistance strain pressure sensor made by Institute of Electronics, Chinese Academy of Sciences, as the core sensing element, and designs corresponding high-precision, low cost, low power amplifying circuit so as to realize accurate detection of atmospheric pressure in time. In this topic, a new design of amplifying circuit is taken, which first connects the digital potentiometer to the bridge circuit to adjust its balance, and then amplifies the output signal of the bridge circuit once to ideal value. This design not only meets the requirement of measurement, but also is feasible and reduces the cost. At the same time, in order to improve the precision of the potentiometer adjusting the bridge balancing, paralleled resistances are creatively used beside the digital potentiometer and its influence to the bridge balance adjustment and the accuracy of the bridge measurement is analyzed in detail.