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Carbonation of concrete causes corrosion of the steel reinforcement and reduces the service life of the structure. Based on the reality that fly ash discharge is increasing year by year and construction sand is becoming increasingly limited, it is of practical importance to study the effect of fly ash dosage and desert sand replacement rate on the carbonation resistance of concrete. Orthogonal test L9(34) with four factors and three levels was designed to study the influence of water-binder ratio, fly ash dosage, sand ratio and DSRR on carbonation resistance of desert sand concrete (DSC). The results of the orthogonal tests were analysed by range analysis and ANOVA and a comparatively better concrete mix ratio was given. Next, single-factor tests were designed to investigate the effects of fly ash and desert sand replacement rates on the carbonation resistance of DSC respectively. The regression model among carbonation depth, fly ash dosage and DSRR was established. The experimental results show that the carbonation depth of concrete with fly ash as a single variable increases with the amount of fly ash, increasing more rapidly in the early stages than in the later stages. As the DSRR increases, the carbonation depth of concrete with desert sand as a single variable first decreases and then increases and reaches its lowest value when DSRR equals 20%. When fly ash and desert sand are mixed into concrete simultaneously, the carbonation depth reaches minimum value on the condition that fly ash dosage is 10% and DSRR is 20%.

A variety of high-density and strong signal electromagnetic jamming and interference effect is one of the difficult problems which have bad effects on the accuracy of GNSS Satellite navigation receivers. For different types of jamming and interference effect, this paper will analyze their corresponding coping strategies on GNSS satellite navigation terminal. On the structure basis of the smart antenna array, the algorithm flow of LMS, RLS and CMA are analyzed and the simulation of these three classic beam forming algorithm are also performed. The comparison result of the convergence curves output and convergent beam directional diagram shows that all of them can extract the useful signal from the interfering signals. RLS algorithm has a better setup speed and convergence rate, and also has a strong adaptability to non-stationary signals. Therefore, its filtering performance is significantly better than LMS and CMA. But due to its high computational complexity, real-time processing is very hard to achieve.

An investigation into gas heating costs of the Garden District residents in the 2010-2011 winter,obtained accurate data of separate household gas heating, and the data were analyzed in order to fully understand district heating costs in energy saving buildings, which provided the basis for household gas heating applications.

The purpose of this paper is to find a solid application and improve the integrated navigation system of aircraft independent landing. The main researches are focused on the issue how to improve the accuracy and reliability of the integrated navigation system, by means of the detailed analyzing about information fusion, and investigating accurate navigation technology for independent landing approach of aircraft. Next, the integrated navigation system models SINS/DGPS/TAN/ILS based on Federated filter are established, and the accurate navigation algorithm of landing is also researched. At the end, the paper gives its simulation results for independent lading approach, which show this algorithm is able to greatly improve the accuracy of speed and location information for aircraft accurate landing.

This article is about the methods and equipment being used in the first step of slime water system, which is called fine particle classification. With the development of automation in coal mining and preparation, fine particles in the raw coal increases substantially. The fine coal preparation is mainly completed in water, which makes the slime water system face to a heavier load. Accurate classification is necessary to large-grained gravity separation and small-grained flotation.

with the parallelism of task implementation, spatial distribution, well system fault tolerant capability and scalability, the multi-agent are widely used in many fields. The multi-agent synchronization control technology has been becoming a hot research at home and abroad. This paper set up unified time and frequency models of both homogenous and heterogeneous-agent, to explore the expression of multivariate time consistency problem. In addition, exploring the received signal strength (RSS) based time synchronization algorithm can enlarge the action range of multi-agent with keeping topologically connection, it also can ensure time synchronization and distance measurement when multi-agent lose satellite positioning function.

A series of γ-Al2O3 modified with different content of polyethylene glycol (PEG) was prepared by a reverse precipitation method. The phase transformation, thermal stabilization and the morphology of PEG-modified γ-Al2O3 was studied by XRD, BET and TEM, respectively. The results showed that the γ-Al2O3 with 1mol% PEG-modified has the excellent thermal stabilization after calcined at 1100°C for 3h. With the content of PEG increasing, the surface area of γ-Al2O3 was reduced gradually. Simultaneity, the γ-Al2O3 phase was transferred to θ-Al2O3 with the surface area 92 m2g-1 and a pore volume of 0.77 cm3g-1. The high surface area maintained at such high treatment temperature shows the 1mol% PEG-modified γ-Al2O3 prepared by reverse precipitation method can be applied in the automotive three-way catalyst support.

In order to study the purification ability of reed wetland soil to phenol and its influence factors, the dynamic soil column method and static degradation method was conducted, the results indicated that wetland soil without reed-planted had a high purifying efficiency to phenol. Both the residence time of phenol in soil and the range of particle size affect the purifying efficiency of wetland soil to phenol. Reed can affect purifying efficiency of wetland soil to phenol by changing soil infiltration and physicochemical properties of rhizosphere.

This article is about casting process of tensioner pulley bracket, which includes solidification simulation, mould filling simulation and defect forecast, using ViewCast software. The scale and location of the shrinkage defects were shown in simulation results. Solidification results demonstrated that the casting defects were not eliminated by the casting technology. The optimized scheme was obtained by replacing and adding chills. The optimization scheme was calculated and the simulation results shown that the reasonable casting process was obtained and the process has been proofed by the productive practice.

In order to achieve high-accuracy, high speed and low cost A/D conversion, a new design based on STC12C5A32S2 single-chip microcomputer (SCM) is given. Compared with the previous A/D conversion, the biggest advantage is that the paper combine software with hardware and it can adjust the speed of transformation through procedure.We don't need to modify circuit, just need to modify signals of input and procedures. So the flexibility of A/D conversion can be enhanced, also saved costs. The design mainly makes use of new function of STC12C5A32S2 SCM to realize conversion between analog signals and digital signals. In order that researchers can analyze and use the convention results, the design add a LCD display module. The paper primarily analyses the design of circuit and interface technology between the SCM and other chips. Also, the peculiar function of STC, the LCD display method of LMB202DDC and the flow of software are expounded in detail. The simulation result based on Proteus is given by the end of paper.

In view of PTP high precise timing requirement for many application fields, GPS time service is provided with the advantages of high precision and high stabilization. The principle and timescale of PTP based on GPS are analyzed and discussed. And then a PTP time synchronization platform with GPS-based UTC time is designed and implemented, the correlative key design flowchart is described as well. Finally, the paper gives the experiment results, which show the time synchronization accuracies can reach nanosecond range.

Active alumina (γ-Al2O3) was prepared from NaAlO2 and HNO3 by a reverse precipitation method with addition of polyethylene glycol (PEG). The effect of PEG additived in the different stages during the preparing process was investigated by powder X-ray diffraction (XRD), fourier transform infrared analysis (FTIR) and nitrogen adsorption-desorption. It was found that the mesoporous alumina sample with the PEG additived into the initial HNO3 solution was the most effective at improving the surface area and the pore volume of γ-Al2O3.

Based on software of Airpak, a mathematical model of a residential neighborhood in Shenyang was built to analyze the thermal environment of the area in summer. Different areas of river system, saying, original and double area, were located in south of the residential neighborhood. A series of results at pedestrian level of 1.5 meters were obtained, such as temperature field, relative humidity(RH) field, Predicted Mean Vote and Predicted Percent Dissatisfied(PMV-PPD), as well as Mean Age of Air(MAA). The simulation results showed that the affect to the thermal environment of the residence were different when the area of river systems was different. All the simulation results illustrated that the thermal environment was better if the area of water system was increased.