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In the present study, the microstructure, martensitic transformation and damping characteristics of Fe-17Mn-xNb (x = 0, 0.5, 1, 2, 4 wt. %) alloys were investigated. Nb addition leads to the variation in both the volume fraction and the size of ε martensite, in addition, the formation of Fe2(Nb, Mn) precipitates. The martensitic transformation exhibits a tiny dependence on the content of Nb. The addition of Nb helps to enhance the damping capacity of Fe-17Mn. The maximum value of tan δ = 0.054 is achieved in Fe-17Mn-1Nb alloy, which is increased by 42% over Fe-17Mn. The damping mechanism caused by adding Nb is discussed in terms of the volume fraction and the size of ε martensite. Besides, the role of Fe2(Nb, Mn) is also taken into account.

Alumina ceramics with good mechanical and corrosion resistance are the ones of the most widely used engineering ceramics. The aluminum has high strength, high conductivity and high plasticity etc. so that aluminum ceramics are used in more and more industries. In this paper, the mass fraction of 25% Al2O3 powder and the mass fraction of 75% Al powder were mixed in the blender. Mixer speed is100r/min with mixing time of 3.5 h. Forming, sintering and a series of processes for preparing the alumina/aluminum metallic ceramic materials, through performance testing and analysis, found that the density of the sample firstly increased and then decreased with the increase of sintering temperature. A melting point is close to the sintering temperature and the density of the cermet can be made relatively high. When the sintering temperature is about 600°C and 700°C, the macro performance of sample is better. The cermet is sintered at 700°C and its microstructure is relatively better.

The average size and density evolution of dislocation loops in AL-6XN austenitic stainless steel, a candidate fuel cladding material for supercritical water-cooled reactor, under proton irradiation were simulated through a rate theory model. The simulation results exhibit relatively good agreement with the experimental results at 563 K. The size and density of defect clusters are calculated under irradiation temperature between 550 K and 900 K and irradiation doses up to 15 dpa which satisfies the working condition in supercritical water-cooled reactor. The fast nucleation between self-interstitials happens at the initial stage of irradiation. The average size of dislocation loops increases while the average density of these loops reduces with the increasing temperature, and the average density approaches to a constant when irradiated at higher irradiation doses. The mechanism is discussed based on the variation of rate constants of defect reactions and the variation of the diffusion coefficients of interstitials and dislocation loops with dose and temperature.

The microstructure, phase transformation and mechanical property of Ni-Co-Mn-In alloy fabricated by powder metallurgical method were studied in the present investigation. The initial polycrystalline alloy was prepared by arc melting and then milled to fine particles, finally the powder particles were sintered by spark plasma sintering (SPS) method to make the bulk alloy with refined grains. The size of as-milled particles was much smaller than the grain size of the initial arc-melted alloy. The particles can be successfully densified to form a compact bulk by SPS. The initial arc-melted alloy presented a good martensitic transformation behavior, whereas the martensitic transformation of the as-sintered bulk alloy disappeared. The compressive strength and fracture strain of the as-sintered alloy greatly enhanced as compared to the initial arc-melted alloy due to the grain refinement and strengthening of grain boundaries.

The polyurethane matrix composites consisting of CNT and NiTi springs are prepared and the microstructure, mechanical property and damping property of the composites are investigated. It was found that the CNT and NiTi spring exhibit a good interfactial bonding with the matrix. The elastic modulus and tensile strength have been enhanced by the addition of CNT and NiTi spring. The NiTi spring is helpful to increase the recovery strain and enhance the energy absorption of the composites by the pseudoelastic deformation under the large deformation. The NiTi spring can not increase the damping property under low vibration amplitude because the pseudoelastity of the spring is not actuated when the deformation is small.

Ti-50.8%Ni shape memory alloy was subjected to four passes equal channel angular pressing (ECAP) with angle 120◦ via route Bc at 450°C. The deformation homogeneity was analyzed on planes across the thickness of the deformed sample by Deform-3D software. Two methods were used from the simulation model to quantify deformation homogeneity , including strain standard deviation (SSD) and inhomogeneity index (Ci). In addition, The deformation heterogeneity of ECAP was analyzed experimentally from microhardness inhomogeneity index ( HII) based on Vickers microhardness test results.In the present work, Ci and SSD had been testified to detect which one could give better results experimentally. It was demonstrated that the simulation results of SSD measurements were in good agreement with experimental results .

OpenMP is one of the most popular parallel programming technique nowadays. Using openMP, programmers parallelized their serial programs by inserting directives. However, in addition to parallel algorithm related overhead which depends on how to design the parallel program, performing openMP also leads to overhead. In this paper, we give a model to evaluate the overhead, and design 5 groups of experiment to evaluate the overhead caused by starting openMP, scheduling and synchronizations. We also analyze the changes of the overhead with different scale of the problems and the number of parallel threads.

First, a certain type of ship azimuth servo system as an example, mathematical model with friction is established, then using LADRC to estimate and compensate the friction disturbance, greatly inhibit the effects of these disturbances on the servo system. The simulation results show that the method of ADRC can greatly improves system capacity and anti-friction disturbance.

Equal channel angular pressing (ECAP) is widely studied for its potential to produce ultra-fine grained (UFG) structure in TiNi shape memory alloys (SMA). In the present work, the effect of multipass ECAP parameters on the deformation behavior and strain distribution was investigated, at various deformation temperatures through different planes in the ECAPed billet. Three-dimensional (3D) geometric model with corner angle 120◦was designed by finite element method (FEM) software for ECAPing Ti-50.8%Ni by route Bcin DEFORM-3D software. Two methods were used to quantify deformation homogeneity through various planes in the processed billet, including strain standard deviation (SSD) and inhomogenity index (Ci). The simulation results demonstrate that by increasing ECAP passes, the cumulative average strain can increase and obtain UFG structure, but heterogeneity still exist across planes. In addition, temperature has a remarkable effect on homogeneity distribution .As well as Ciexhibits good results for multipass ECAP at various deformation temperature compared to SSD value.

The cyclic oxidation behavior of Co-10Cr-5Al alloys with and without 0.3 at% Y doped in atmosphere at 800oC was investigated. The addition of 0.3 at.% Y increased the oxidation rate of the alloy and changed the oxidation mechanism. The scales grown the alloys with and without Y were both composed of an outer Co2O3layer and an inner complex layer of Al2O3, Co2O3and Cr2O3, except that the addition of 0.3 at% Y enhanced the adhesion of the scale. 0.3 at% Y agglomerated in local zone which accelerated the oxidation rate and was not conductive to the oxidation process of the Co-10Cr-5Al alloy.

In view of fake and shoddy cotton seeds appearing constantly, it damaged the interests of the farmers seriously. Accordingly, this paper proposed a method to solve the cotton quality and safety, which combined the technology of Radio Frequency Identificaiton (RFID) and the Internet. The cotton circulation management model has been constructed, developing the cotton quality traceability system. This will not only can help consumers identify the cotton quality, but also can prevent unqualified cotton into the market so as not to protect the interests of farmers and manufacturers reputation.

The article proposed a new research. The method may avoid interference of reverse drive vehicle by installing back-to-back reader in section, adopting active electronic tags to expand the scope and accuracy about reading and writing, using the information including the number of electronic tags in scanning section, update ratio, residence time to build the linkage system between control system and vehicle-mounted electronic tags, and cooperating with the signal condition in intersection, to make the discrimination of traffic state, especially the discrimination of congestion state. The method could identify the traffic state effectively, which was verified by simulated experiment through secondary development of VISSIM.

In view of the traditional zero-angle memory device with low precision and to reduce errors caused by manual readout, this paper using electro-magnetic technology, designed a new zero-angle memory device based on proximity switch. Experimental results show that the device not only improves the repeatability and reduces the error, but also realize automatic demarcation.

The process of PID parameters turning is complicated and time-consuming to engineering technician. To solve this problem, simulating the Z-N method of engineering turning, based on the simulink, a simple and efficient method for PID parameters turning is presented in this paper. Compares with the general methods, it has many advantages, such as simplicity, visual manipulation, leaving out the work load of program and so on. The simulation results show the effectiveness of this method and be fit for application in the engineering.

Aiming at the problem of electromagnetic interference in design and application of electronic rectifier and inverter system, introduces the electromagnetic interference and electromagnetic compatibility characteristics of common circuit, the interference test of rectifier and inverter system, puts forward the products it has produced inhibition method of interference. The test results show that the method can reduce electromagnetic interference system greatly.

The cyclic oxidation behavior of Co-10Cr-5Al alloys in atmosphere at 700 °C was investigated. The addition of 0.3 at.% Y changed the oxidation behavior from the approximate parabolic rate law to complex mode. The scale grown on the surface of Co-10Cr-5Al cracked seriously, while the oxide scale the Y doped alloy had better adhesive property. Yttrium doped in the sample promoted the forming of continuous Al2O3layer and decreased the oxidation rate of Co-10Cr-5Al alloys.

The cyclic oxidation behavior of Co-10Cr-5Si alloys with and without Y in atmosphere at 700 °C was investigated. The addition of 0.3 at.% Y decreased the average parabolic rate constant from 4.39×10-10g2cm-2s-1to 3.42×10-10g2cm-2s-1. The surface components with and without Y were both composed of an outer CoO and inner protective SiO2. There were more SiO2formed when Y doped into the alloy. The addition of 0.3 at.% Y improved the cyclic oxidation resistance of the Co-10Cr-5Al alloy.

On account of the design method shortcomings of cold recycled (CR) mixture with emulsified asphalt,the material compatibility problems between emulsifier and asphalt and RAP were researched,by which the key indicators of emulsified asphalt and the emulsifying effect of different kinds of emulsifier for asphalt is concluded, and summarizes the basic principles of special emulsified asphalt selection for the high-performance CR technology. On the basis of the research at home and abroad, the early strength evaluation methods and indicators are also discussed in this paper that puts forward to three kinds of test methods: cohesive test, raving loss test, coreability test.Finally,the evaluation method was verified in practical project and reached the effect to be hoped.

Grid Workflow Language Yu wan jun1,2, Liu Yunxiang1,2, Fang Hua1,21 Shanghai institute of technology, School of computer science and information engineering, Shanghai, 201418, China 2Shanghai institute of technology, research center of machine olfaction, Shanghai, 201418, China Key words:Intelligant System; Grid Workflow; Activity; Parallel Structure; Abstract:Grids specification is one of the imporant contents in grid workflow fields, it can shield details of underling grid, so users can concentrate on the description of Grid applications. AGWL(Abstract Grid Workflow Language) is an abstract language based on XML, it was always used to describe grid workflow. The basic activities are connected by the control flow and data link. AGWL uses advanced control flow to support the parallel execution of conditions and loops. As an example, we finally introduced a sales process to show the capacity of the grid workflow language AGWL.

A template technology has been applied to the platform of machine olfaction. The simulation sensor array template receives field odor data or simulates the data via recorders in database, and transmits to the platform. The platform consists of several distributed monitoring subsystems based on the simulation template. Each subsystem matches a set of gas sensors array, and has functions of logging data, communicating and simulating industry application. The data from the subsystem and the preprocessed data are sent to the web server center and stored in the databases. The data has been collected, and sensor performance analyzing are performed by several layer algorithms. While the exchanging algorithms convert the field odor data to gas concentrations with ppm values, the expert systems or recognition algorithms analyze the ppm values and show the application results. All data of each layer are stored in server database systems, and each layer algorithms can been updated and saved. Finally, the supporting platform that applied to industrial monitoring systems, was developed with a kind of industrial configuration softwares, web MIS and databases, and was utilized to realize monitor to the environmental systems by the simulation template.

The construction of Electronic Nose system and associated signal processing methods were introduced .Then special references to applications to dairy products, such as the classification of different milk, the milk with different shelf-lives, flavor quality evaluation, antibiotics resedues detection and quality control were discussed. The results show that the quality of dairy products can be evaluated effectively using Electronic Nose system. The development trends of Electronic Nose are presented.

In this paper, an air quality monitoring system based on sensor array and framework of cloud computing is implemented. This system can surveil and report the information gathered from the ambient air condition in real time and inexpensive way, it can protect the public's right to know about the environmental security that everyone living in. All efforts and works of this paper is to turn the dreams into reality: to preserve and improve the quality of our living environment's air, in the sense of keep the damage to our health far away, through the strong pressure of public opinion.

Electronic nose is an intelligent sensory analyzing instrument which simulates the biological olfaction system. Classification is very important for an electronic nose which is usually seen as the software of E-nose. In this paper, we present a model of classification based on genetic algorithm. Compared with common classification algorithms, genetic algorithm had more powerful flexibility and global searching capability. In this paper classification rules were represented in the form of chromosome by binary codes which are in accordance with the features of sensor data. F-measure was used as fitness evaluation. We also designed efficient crossover, mutation operators.

Vehicular environment with the fast varying and fast moving character calls for the support of security communication technologies. The solutions based on watermark and VPN (Virtual Private Network) are discussed to realize security communication of DSRC (Dedicated Short Range Communication), which is earmarked for motor vehicles to exchange information with each other in the area of ITS (Intelligent Transport System).Finally this paper analyses the characteristics of the solutions.

The cyclic oxidation behavior of Co-10Cr-5Si alloys with and without Y in atmosphere at 800 °C was investigated. The addition of 0.3 at.% Y decreased the average parabolic rate constant from 4.45×10-10g2cm-2s-1to 3.58×10-10g2cm-2s-1. The thin scales grown on Co-10Cr-5Si alloys were mainly composed of an outer CoO layer, followed by an inner protective SiO2layer. However, the scales can not be observed for Co-10Cr-5Si-0.3Y alloy, probably due to the spallation of the scales during the cooling process. The addition of 0.3 at.% Y improved the cyclic oxidation resistance of the Co-10Cr-5Al alloy.

For assessing the joint operations command and staff objectively, the paper established a joint command personnel ability evaluation of multilayer index system. In view of the majority of interval-valued intuitionistic fuzzy information that is only used for single layer multi attribute index system. In the case of the two grade index attribute weights unknown, we utilized the score vector projection formula and obtained the pros and cons of the commanders in all levels under the one class index attribute. Finally we apply the ladder structure comprehensive assessment method to get the comprehensive ranking. It provide a certain basis for the selection of the joint operational commanders

The cyclic oxidation behavior of Co-10Cr-5Al alloys with and without Y in atmosphere at 800 °C was investigated. The addition of 0.3 at.% Y increased the oxidation rate of the alloy and changed the behavior from irregular oxidation kinetics to approximate parabolic rate law. The scales grown the alloys with and without Y were both composed of an outer Co2O3layer and an inner complex layer of Al2O3, Co2O3and Cr2O3, except that the addition of Y impaired the adhesion of the scale. Over-doped Y agglomerated in local zone plays an adverse role in the oxidation process by accelerating the oxidation rate.

The Research of fire occurrence and the law of development, and the prediction of the risk are the key to prevent and extinguish the fire effectively. This paper uses FDS to build the building model and track the production and movement of fire and smoke, combined with the material properties of furniture, walls, floors and ceiling to calculate the growth and spread of fire. Finally, write the data analysis platform FireSim to read and analyze the output data of FDS, and give the fire danger rating, so as to help people prevent fire and reduce disaster.

High-quality SnO2 thin-film materials capable of detecting H2S gas of low concentrations at room temperature was demonstrated in this paper. We employed aerosol-assisted chemical vapor deposition process for the deposition of SnO2 thin films on alumina substrates with pre-patterned electrodes. The gas-sensing performances of the films prepared under different deposition conditions were systematically compared and analyzed. When SnCl2·2H2O was used as the precursor, a response sensitivity of 98.4 toward 50 ppm of H2S at room temperature was achieved. At room temperatures, the resistance upon the H2S gas exposure could recover to 90% of the initial resistance of the sensor when the H2S gas flow was turned off.

By using particle flow code (PFC2D), influence mechanism of isolation layer to granular media flow was studied by simulating two ore-drawing modes of filling mining method (working condition Ⅰ) and synchronous filling shrinkage method(working condition Ⅱ). After analyzed simulation results, some laws were gotten: (1) by the fitting process conducted on released volume and height, it is found that the relationship of released volume and height was power equation, which is same as the stochastic medium theory for ore-drawing; (2) The released volume, the size in most width of loosing body and the location of working condition Ⅱ was both bigger than those of working condition Ⅰ; (3) the radius of curvature of drawn-funnel of working conditionⅡ was bigger than those of working conditionⅠ, but the volume of residual ore was opposite. Analysis shows that the isolation layer reduced the contact force in ore drawing regional, made the porosity bigger, so as to improve liquidity. The results provide a theoretical reference for the changes in underground mining techniques and ore-drawing control.

With a uniform linear antenna array, a new direction-of-arrival (DOA) estimation method is proposed for wideband coherent signals in the presence of unknown correlated noise but with structured covariance matrix. Based on this proposed structure, i.e. Hermitian Toeplitz, a spatial differencing operation that exploits this symmetry is applied to remove the effect of the unknown noise and a new matrix is constructed accordingly at each frequency bin. Following this step, a focusing operation is performed to give the corresponding aligned covariance matrix. Finally, an eigenstructure-based DOA estimation method is applied. The validity of the method is supported by numerical simulation under various conditions.

In traditional traffic signal coordination control, all intersections are shared a common cycle and have fixed offsets in one sub-area. The range of sub-area is normally fixed, plan switching is difficult, and the reaction to the traffic problem is slow. In this paper, a self-organized dynamic control strategy is proposed. it decomposes the network optimization into overlapped and interactive problems between Basic Coordination Units (BCU). It presents an interaction-forecast model among intersections, each intersection not only considers its own benefit, but also takes downstream intersections into account. Multi-scenarios simulation shows it works well in all saturation degrees, reduces total delay around 8% to 12.3%.

Closed concrete cut-off wall has been widely used in the reinforcement projects of earth-rock dam. However, the research on the cut-off wall was rare. In order to discuss the stress state of the wall under different engineering conditions, a coupled numerical model was established by considering coupled interaction, including contact between wall and dam, and coupling of stress and seepage. Taking the earth-rock dam which built on common foundation for example, the stress distribution of the wall and influencing law of different factors were mainly researched, including elastic modulus of the wall, deformation modulus of the dam filling materials, permeability coefficient of the dam foundation, etc. The conclusions had reference significance for the application and design and calculation method of concrete cut-off wall in the reinforcement projects of earth-rock dam.

This paper puts forward pseudo-response spectrum method for calculating the dynamic response of structure caused by harmonic load on the floor, and proposes to use frequency ratio as a new modal truncation index. Combined with engineering practice, the analysis results of pseudo-response spectrum method were compared with the results of existing dynamic coefficient method and elastic time-history method. The contrast results show that dynamic coefficient method due to lacking of considering dynamic properties enough was not able to meet the real response and could not evaluate the comfort of the vibration. The results of pseudo-response spectrum method with suitable mode combination method have the same law of the maximum enveloping value as elastic time-history method. This proved that pseudo-response spectrum method is reasonable, safe and economical, which can provide the basis for engineering design.

With vigorous development of hydroelectric source in west China, the anti-seismic security issue of dam engineering attracted particular attention. This paper presented the principle of dynamic time-history analysis method and established the model with the assistance of finite element method and combined with practical engineering for further analysis on the dynamic response of displacement and stress of dam’s dynamic time-history analysis to the time history. According to the result, it is feasible and necessary to apply the dynamic time-history analysis method to study the anti-seismic performance of the dam. Furthermore, it pointed out the weak part of the dam in anti-seismic function as well as the area concentrated with critical stress, providing reference for future anti-seismic engineering and shock resistance.

Markowitz mean-variance model was the first applied to study rural infrastructure investment and a rural infrastructure optimal portfolio was established to find the optimal investment proportion of rural infrastructures with maximum total return. Fuzzy mathematical method was used to model solution for the fuzziness of rural infrastructure return and rural Shaanxi was taken as an application tested the feasibility of the model.

Painting is one of the most important processes in decorating industrial product. But the vacuum container is the key of vacuum painting equipment. This paper analyzes the principle of dismountable vacuum container’s structure and establishes its basic physical model and simulates its environment load by the finite element software, then analyzes the important component and obtains the index of reliability and safety of dismountable vacuum container. According to the classic theory of elastic thin plate, the accuracy of the results of finite element analysis is proved. Then the further optimization design and the further finite element analysis are utilized to optimize the important component of vacuum container, finally the results meet the requirements.

Exampled on the catchments area of LiangTan River in Chongqing, this paper analyzed the Ecological potential ecological hazard of water heavy metal, such as Hg、Cr、As、Zn、Pb. The result shows that in the dry seasons, about water heavy metal potential ecological hazard, from high to low the order was Cr>As>Pb; on the other, in the rainy season, the order was Cr>Pb> Zn. Then, we calculated the economic losses inside in urban and rural connection area in chongqing. It was about 1.08*109 Yuan per year, and it was 4.29% of total production value of rural industry. Plus the potential ecological losses and agriculture production losses, it up to 3773723.2*104～66093601*104 Yuan per year. Compared to gross profit of rural industry, it was 34 times, and up to 77.5% of total rural industry output.

Abnormal vibration was found in a rocket engine test, to guarantee the stability of the rotor when its working, in this paper, by studying the turbine assembly process and pump assembly process, research of the factors such as correlation among the assembly torque, the pre-tightening force, part parameters and assembly parameters etc was applied. By studying the assembly process of turbine pump shaft, analyzing the of the role of the turbine shaft Parts parameters in the assembly process, by selecting the shaft parts and assembly experiments, theoretical basis and data preparation are provided to improve the quality of the turbopump assembly.

A three-dimensional thermo-mechanically coupled FEM-simulation of the production of a connecting rod has been performed between dies (pre- and final-forging). According to the part’s characters and its dimensions, a hammer die forging process was determined. According to the hammer die process, three-dimensional connecting nod model was built in UG software and two different cases for pre-forging was designed. Different forming case was simulated by Deform-3D FEM program, the effective stress field and effective strain field were analyzed by comparison; it proved that optimized performing process was reasonable and can be used as reference in production.

By analyzing the relationship between nanotechnology and medical science, especially nanotechnology and acupuncture, the application of nanomaterials for needling therapy, acupoint catgut embedding therapy, acupoint external application, acupoint injection therapy, and meridian point diagnosis were discussed. Nanomaterials will make the development of acupuncture possess an unprecedented domain. It’s pointed out that breakthrough will be achieved from the research of the application of nanomaterials on the development of nano-needles for needling therapy, nano-thread for acupoint catgut embedding therapy, nano-medicine for acupoint external application therapy, nano-drug carrier for acupoint injection therapy, nano-sensor for meridian and acupoint diagnosis.

Two range-free node localization schemes modified from the conventional DV-Hop scheme are presented in this work. Different node position derivation algorithms are used to enhance the localization accuracy of DV-Hop. The principle of the algorithms and the improvement approach are illustrated. Simulation shows that the modified schemes outperform the original scheme in terms of the localization accuracy as the network connection topology varies.

The granite is widely used for city architectural decoration, outdoor sculpture. Study on granite reflection is important for artificial building recognition and rock or mineral exploration. The Bidirectional Reflectance Distribution Function (BRDF) is used in conventional remote sensing to characterize the geometrical scatter of materials. Polarization occurs with multi-angle scatter. 90°and 0°polarized bidirectional reflection along the waveband of 300~2500nm for various view azimuth and zenith angles on polished granite are acquired. DOP then is calculated.

Under field research in Shaanxi province, the rural infrastructure project evaluation index system based on sustainable development is proposed to promote the sustainability of the project during decision and regulate the construction of rural infrastructure. Corresponding to the structure entropy weight method defining the index weight, the system consists of 9 evaluation factors and 46 evaluation indexes from economic, social, environmental and technical is built up, and taking Shannan district and Guanzhong district in Shaanxi province as examples to do empirical analysis. The result exhibits the local development rational, which proves the validity of rural infrastructure project evaluation index system based on sustainable development.

16 items of assessment indexes are selected to build up the safety risk assessment index system of special maintenance project according to the construction safety characteristics of highway special maintenance project, based on which, the safety risk assessment model of special maintenance project based on BP neural network is brought forward. The assessment model has been trained, checked and analyzed through example and it turns out that the effective safety risk assessment of highway special maintenance project can be calculated based on this model, which also supplies decision-making basis for the project safety management.

Viscous dampers are widely used in vibration energy dissipation project. The researches on viscous dampers used in energy dissipation project at present are more, and one of the main research contents is about how to improve energy dissipation efficiency. In the current study, the effect of the supporting stiffness in dampers is neglected, and only its strength and stiffness is verified. Based on the research on the principle and mechanical model of viscous damper, the influence of supporting stiffness on various energy dissipation working parameters has been analyzed in this paper. The results showed that, supporting stiffness has great influence on the energy dissipation efficiency, then with energy dissipation efficiency as the index, this paper derived the generality support stiffness design formula for energy consumption optimizing, which provide scientific basis for similar design.

Pore structure is one of the main influencing factors of materials drying shrinkage. C30 natural mix proportion is used as reference, the impact of replacement rate of recycled aggregate, the mixing amount of fly ash, water reducer, expansion agent and water-cement ratio on recycled aggregate concrete’s porosity and pore characteristics was studied. Based on the pore structure theory, the influence of porosity and pore characteristics on recycled aggregate concrete’s drying shrinkage is analyzed.