In this paper, the effects of water-cement ratio, air-entraining agent type, and air content on the pore characteristic parameters of hardened concrete were investigated through an extensive series of experimental studies. First of all, according to different water-cement ratios, air-entraining agent types, and air contents, the correlation between the concrete pore spacing factor and the frost resistance durability factor was revealed by using the automatic analysis and testing instrument for the pore system of hardened concrete. Then, the decision tree method was utilized to propose specific pore spacing factors for different concrete scenarios, including the non-air-entrained concrete, air-entrained concrete, concrete with unqualified frost resistance, and concrete with qualified frost resistance. In cases where the pore spacing factor measurement fell within an ambiguous range, the classification was further refined according to the water-cement ratio. On that basis, the comprehensive range of pore spacing factors for the concrete with a qualified frost resistance was determined. Finally, the post-evaluation method and standard procedure for assessing the frost resistance of concrete entities based on pore spacing factor and water-cement ratio were proposed to verify whether the frost resistance of concrete buildings meets the life expectancy requirements. This method facilitates the evaluation of the frost resistance quality of newly-built concrete projects, as well as the investigation and monitoring of frost resistance in existing structures during service.

为了解决再生混凝土在复杂环境条件下的耐久性能研究匮乏问题,对5种再生混凝土进行碳化、干湿与冻融耦合作用下的耐久性试验,测试其动弹性模量、氯离子迁移系数、碳化深度及微观孔隙特征参数,并引入孔隙迂曲度指标进行分析.结果表明:交替碳化与干湿对再生混凝土的冻融劣化效果有显著促进作用,累计碳化42 d与干湿循环42次可使再生混凝土冻融损伤量增加21.9％ ～26.9％,抗氯离子渗透性能降低45.05％ ～96.18％;与单一碳化42 d相比,交替干湿循环42次与冻融循环300次可使再生混凝土的碳化深度增加1.6～3.5倍.此外,碳化、干湿作用均增大孔隙迂曲度,而冻融及三因素耦合作用均减小孔隙迂曲度;孔隙迂曲度与氯离子迁移系数及相对动弹性模量均具有显著的相关性,在一定程度上可作为再生混凝土耐久性能评价指标.

The influences and mechanisms of single and coupled effect of carbonation, dry-wet cycles and freeze-thaw cycles on the durability of three types of recycled aggregate concrete were studied. The compressive strength, chloride ion migration coefficient and micro pore parameters of recycled aggregate concrete were tested. The results showed that carbonation and dry-wet cycles can improve the pore tortuosity and reduce the connectivity of pores, while freeze-thaw cycles, coupling of carbonation and freeze-thaw cycles, and coupling of carbonation, dry-wet cycles and freeze-thaw cycles can significantly reduce the pore tortuosity and deteriorate the pore structure. The key reason for durability failure of recycled aggregate concrete in a complex environment is the increase of large pore volume fraction. When more factors are coupled, the increase in the pore volume fraction is greater. Based on the pore tortuosity and large pore volume fraction, an integrated pore index was proposed, and a prediction model of compressive strength and chloride ion migration coefficient of recycled aggregate concrete under complex environmental factors was established, which provided the basis to evaluate and maintain the durability of recycled aggregate concrete. (C) 2020 Elsevier Ltd. All rights reserved.

为探究赤泥回收利用方法,以烧结法赤泥为活性材料,不同模数的水玻璃溶液为激发剂,制备了赤泥基碱激发胶凝材料,测试了其力学性能及孔结构特征,并通过XRD、SEM及差热分析探究了其微观机理.试验表明,水玻璃模数对材料性能有较大影响,水玻璃模数为0.96时体系的激发效果最好,28 d抗压强度达到10.21MPa.硬化试件的主要强度来源物质为水化硅酸钙凝胶,强度较高的材料其微观结构更为致密,碱激发产物数量更多.

The effect of different aggregate treatment methods on the properties of both the recycled aggregate and the recycled concrete was studied. In this work, the compressive strength, dynamic elastic modulus, dry shrinkage rate, and chloride ion migration coefficient for five types of recycled concretes were investigated. Moreover, the Vickers hardness index and micro-morphology of new and old interfaces were analyzed. The results showed that "carbonation" significantly improved the mechanical properties and the dry shrinkage resistance of the recycled concrete. However, "slurry wrapping" greatly enhanced the chloride ion penetration resistance. Different aggregate treatment methods had different mechanisms to strengthen the interface. The influence of "carbonation" on the old interfacial zones (ITZ) was more significant than that on the new ITZ. A contrary influence of the "slurry wrapping" on both old and new ITZs was observed. The old interface had an obvious effect on the compressive strength and dynamic elastic modulus, while the new interface with different treatments had a non-negligible influence on the chloride penetration resistance. Besides, in this study, two optimization methods were proposed based on the improvement of "carbonation" and "slurry wrapping" treatment, respectively. These optimized methods can further improve the quality of recycled aggregate and the performance of recycled concrete. (C) 2019 Elsevier Ltd. All rights reserved.

为探讨混凝土在不同环境因素下的抗氯离子渗透性能变化规律及机理,开展了三种类型混凝土分别在标准养护、干湿循环、冻融循环和碳化条件下的试验研究,测试了混凝土氯离子扩散系数、碳化深度及微观孔隙参数,探讨了混凝土抗碳化与抗氯离子渗透性之间的关系,并引入"混凝土孔隙曲折度"的概念进行了分析.结果表明,混凝土氯离子扩散系数与孔隙曲折度之间具有良好的负相关关系,不同环境因素对混凝土抗氯离子渗透性的影响不同,主要与孔隙曲折度对不同作用的反应不同有关.标准养护、干湿循环和碳化均可以提高孔隙曲折度,但冻融循环会降低孔隙曲折度.此外,矿物掺合料的掺入可以细化孔隙结构,提高混凝土孔隙曲折度,从而提高其抗渗性.

为了解决城市建筑垃圾再生利用水平低、道路管沟回填施工周期长的问题,将建筑垃圾细料应用于早强型控制性低强度材料(controlled low strength materials,CLSM)中,考察促凝剂掺量、促凝剂类型、水固比与胶集比等因素对CLSM的工作性能、力学性能及抗干缩性能的影响.研究结果表明:促凝剂对CLSM流动度无明显影响,但对泌水率与干缩率有显著削减作用;2种促凝剂的早强特性存在一定差异,其对应的最优掺量分别为40％与20％,4 h强度均为0.7MPa以上;在促凝剂掺量一定时,早期小时强度受胶凝材料总量与实际自由水量的综合影响;增大水固比可提高流动度、泌水率及抗干缩性能,降低力学性能,而增大胶集比可提高流动度与力学性能,降低泌水率与抗干缩性能.

Rapid-hardening controlled low strength material (CLSM) containing recycled fine aggregate from construction and demolition (C&D) waste was prepared with the sprayed concrete accelerator. Eleven mixtures were made with different accelerator-to-binder (A/B), water-to-solid (W/S) and binder-to-recycled fine aggregate (B/R) ratios. The workability (flowability and bleeding rate) of fresh mixture and the mechanical properties (early strength, long-term strength and dynamic elastic modulus) of hardened material were tested. The results show that adding (20 similar to 50%) accelerator reduces the bleeding rate of CLSM by 48.8 similar to 84.6%, with no significant effect on the flowability. Improved flowability of CLSM can be achieved by increasing the W/S or B/R ratio, with increased or reduced bleeding rate, respectively. The optimal A/B ratio for best early strength development is 40%, with the early hour strength (2 similar to 4 h) up to 0.41 0.79 MPa. When A/B ratio is held constant, the early strength of CLSM is affected by the amount of cementitious materials and the actual content of free water. An accurate predictive model for the long-term strength of CLSM was established through regression analysis, in which three control parameters are considered. A power function relationship between the compressive strength and the dynamic elastic modulus is also established. Dynamic elastic modulus can thus serve as an indicator for evaluation of the mechanical properties of CLSM. (C) 2018 Elsevier Ltd. All rights reserved.

Rapid freezing-thawing tests of concrete were conducted in laboratory after different carbonation times.The mechanical properties and microscopic pore characteristic parameters were investigated,and the concept of "pore sinuosity" of concrete was put forward.The test results indicate that carbonation contributes to enhance frost resistance of concrete,the 3-14 days' carbonation can make dynamic elastic modulus of concrete reduce at least 3％-12％ due to freezing-thawing cycles.Carbonation increases pore sinuosity of concrete.Moreover,fly ash can also enlarge pore sinuosity of concrete,and erosion medium's seepage path becomes longer,thus the frost resistance of concrete is enhanced.The correlation between air-entraining and pore sinuosity of concrete is loose,which shows that the mechanism of frost resistance affected by air-entraining and mineral admixture for concrete is different.

Based on carbonation-only test,freezing-thawing-cycle-only test and alternate test between carbonation and freezing-thawing cycles,relative compressive strength,relative dynamic modulus of elasticity and carbonation depth of concrete were measured and analyzed.Test data show that for the alternate actions between carbonation and freezing-thawing cycles,relative compressive strength of concrete is higher than that exposed to freezing-thawing-cycle-only process,but the increase is limited;its relative dynamic modulus of elasticity is lower than that exposed to freezing-thawing-cycle-only process;whereas its carbonation depth is larger than that exposed to carbonation-only process.The frost resistance and carbonation resistance of concrete decrease compared to that exposed to freezing-thawing-cycle-only and carbonation-only processes,respectively.Finally,a compressive strength fitting model subjected to the alternate actions between carbonation and freezing-thawing cycles is established,in which two independent variables (carbonation time and number of freezing-thawing cycles) are taken into account.

针对含红砖建筑垃圾流动性回填材料泌水率较高的问题,探讨了膨润土对含红砖建筑垃圾流动性回填材料工作性能的影响,提出了最佳掺量.实验结果表明:膨润土可以明显降低含红砖建筑垃圾流动性回填材料的泌水率,但同时降低了回填材料的流动性,膨润土的掺加量为建筑垃圾细料的1％为宜.

A new type of backfill materials using recycled brick and concrete waste as fine aggregates was designed with three cement-to-sand ratios (C/Sa)and five fly ash-to-sand ratios (FA/Sa).A series of measurements were conducted to investigate the fluidity and bleeding and mechanical properties including uniaxial compressive strength,stress-strain relationship,constitutive relation model and elastic modulus. The results showed fluidity had linear correlation on water-to-solid ratios(W/So);the range of the bleeding rates was in 4%~8% when the fluidity was within 200~250 mm.The compressive strengths had an exponential relationship to the cement-to-sand ratios and water-to-solid ratios. A constitutive relation model was put forward to describe the stress-strain relationship curve of backfill material on the base of the model of the concrete.The relationship between the unconfined compressive strength and elastic modulus was established,which could be used to calculate the modulus of backfill materials by the compressive strength directly.

For investigating the changes of mechanical properties of concrete under the action of different degradation,tests of compres-sive strength and dynamic elastic modulus of three kinds of concrete under the condition of freeze-thaw cycles,dry-wet cycles,carbonation and chloride erosion were executed respectively.The results show that the influence mechanism of different deterioration effects on con-crete mechanics properties is different,the damage effects of freezing and thawing test on mechanical properties of concrete is biggest. When the freezing-thawing cycle reach 300 times,the strength loss rate of three kinds of concrete is 30.1%,51.4% and 23.3% respectively, and the loss rate of dynamic elastic modulus is 2.8%,10.1% and 21.6% separately.The damage effects of chloride erosion and short-term drying-weting circulation on the mechanical properties of concrete is not apparent,and carbonation is conducive to improve its mechanical performance.There is a good relationship between compressive strength and dynamic elastic modulus of concrete under standard curing condition,however,such relationship will change together with the change of type of concrete and deterioration.

In order to solving the problem of weak observability and low positioning precise in bearing-only target tracking,this paper improves a method that employing radar to support electro-optical system with batch ranging for object localization,which succesfully improves not only the observability of target tracking,but also the object positioning precision.The technology could greatly reduce the risk of exposure of radar,and makes full use of electro-optical system and radar.Finally,it increases the total combat effectiveness greatly.

针对机载红外图像中运动弱小点目标检测的难题,提出了一种基于PSO-GA训练参数的形态学滤波器。以粒子群优化算法（Particle Swarm Optimization,PSO）为主线,按PSO算法中标准的速度和位置更新,遗传算法（Ge-netic Algorithm,GA）采用新的区间离散化编码和自适应的主次式交叉与变异算子,将遗传算法与粒子群优化算法的自动更新特征结合在一起,通过优化搜索全局空间获得形态学滤波器的最优参数,进而确保优化的形态学滤波器具有良好的滤波性及时效性。通过对低信噪比红外图像（SNR约为2）的测试,检测概率可以达到98%以上,与利用神经网络（Neural Network,NN）训练结构元素后的Top-Hat形态学滤波器相比提高了2%～3%。与GA算法相对,训练算法效能提高20%,提高了搜索最佳值的能力。

A multi-group independent detection method was proposed for detecting the moving spot target in infrared sequence images. The morphological filter optimized by neural network was used to suppress background information, and single-frame target detection was realized by the adaptive threshold method. In multi-frame detection, firstly, the possible trajectory of the observation sequence was grouped and calculated, then maximum likelihood test was carried out. Since the multi-group independent detection took account of the low SNR or strong noise, the determination and elimination of trajectory were quickened in certain degree, and the performance of the multi -frame detection was increased. Here the method of multi -group independent detection was proposed, and the detection performance of grouping sequential test was analyzed. Experimental results show that the detection probability of the proposed method is higher than that of the truncated sequential test with same false alarm probability.

The Top-Hat morphological filters are a class of nonlinear signal processing algorithms, which have been applied extensively to computer vision, image processing, and more recently target detection. In this paper a novel method for optimal learning of morphological filtering parameters for spot target detection is presented. We show how the genetic algorithms can be used for an automatic optimization of structuring elements. Experimental results show that the identified probability to the image of SNR 2 can reach more than 98% by this method.

In this paper,a novel idea of grouping sequential is presented based on MHT for spot target tracking.We present an independent detection of the multiple groups and compare this method with the truncated sequential tests through emulation.Experimental results show that the detection probability of this method is close to the truncated sequential tests while has less complexity than the latter with the same false alarm.

Node localization is a hotspot in international research of Wireless Sensor Network(WSN).Location error cumulate is a key problem to deal with in node localization.Error cumulate could be restrained effectively by using Weighted Least Square Estimates(WLSE).How to apply WLSE to node localization algorithm and choose proper weight coefficient to reduce location error are introduced.Simulations studies show that WLSE perform well by restrain the error cumulate and improve location precision.

As a novel information acquirement and processing technology,Wireless Sensor Networks(WSN) can inspect,apperceive and collect the information of all kinds of environment and surveillance objects in a real-time way,and the embedded operation system which is operated in network nodes is the base of most of applications of WSN.After the analyses of the(newest) productions of WSN architecture, this paper brings forward the design targets of embedded operation systems of WSN,analyzes the general-purpose multi-tasking OS μC/OS-II and event-driven OS TinyOS,points out the limitations of TinyOS in some applications,and the improvement schemes.