Abstract:In order to study the cracks of multi-story masonry buildings, according to the simple similarity principle of model test, a 1:4 scale six-story H-type small-sized hollow concrete block masonry model was constructed, which arranged a constructional column-beam system in each story. By carrying out the test under vertical load and imitating the load difference between the bearing wall and non-bearing walls, the deformation and cracking behaviors in multi-story masonry buildings were investigated. The test indicated that the compression deformation increased with the increase of the vertical load. The vertical load resulted in different deformation between the bearing wall and non-bearing walls, which led to cracking on the bearing wall near non-bearing walls. Besides, the vertical deformation at the central section of the bearing wall exceeded those at the intersection between the bearing wall and non-bearing wall. Due to the increase of the tensile stress of the bearing wall, cracks occurred at the top section of non-bearing walls near the bearing wall's ends. With the increase of vertical load, the previous cracks enlarged and developed along with new cracks. The constructional column-beam system restricted the differential vertical deformation effectively.

Abstract:In view of the shortcoming of traditional fuzzy comprehensive evaluation, which is a coarse quantification of qualitative indexes without regard to holistic information in the evaluating process，a method of qualitative index quantification with fuzzy mathematics was proposed．Grey system theory was introduced into the multi-attribute fuzzy optimal selection of the design scheme, and the fuzzy optimal selection model was formed on the basis of the grey relational analysis．Taking a highway of Shanghai as an example, it proves that this model is feasible and effective when it is applied to the selection of the best treatment of the preventive maintenance of highway asphalt pavement．

Abstract:The subsidence depth of mining equipment and the bearing capacity of deep-sea sediments are important to the design of mining equipment. In this paper, firstly, the subsidence depth model of mining equipment was proposed by using the limit balance theory, according to the deep-sea sediments' physical properties, subsidence, bearing mechanism, and its shear strength changing with depth. Secondly, the bearing capacity of deep-sea sediments is closely related to the subsidence depth of mining equipment. The deep-sea sediment bearing capacity method controlled by subsidence depth was presented on the basis of the subsidence depth model. Finally, the case study and indoor simulation test indicate that the model proposed is reasonable and feasible.

Abstract:According to the ecological damage and instability of highway slopes, a theoretical research on the mechanism of ecological protection slope and an experimental study of the tensile of roots for its anchoring ability were presented. It has been proved in theory that soil shear stress is transferred to roots tensile stress through the frictional force of root-soil contact surface to improve soil shear strength, and soil granules around roots surface are aggregated through much high polymer produced from the growth of roots to resist slope soil erosion by rain. The tests have been based on the tensile strength of the roots of young robinia pseudoacacia. The results have shown that the maximum tensile strength of lateral root is higher than the maximum tensile strength of taproot, and the maximum value is up to 91.41MPa. Compared with the design tensile strength 210MPa of steel HPB235, its tensile strength is as great as 1/4~1/2.

Abstract:A -p--linear dimensionless average fluid temperature was proposed to estimate borehole thermal resistance. A -p--linear dimensionless fluid temperature and the -p--linear dimensionless average fluid temperature were introduced, and the -p--linear dimensionless fluid temperature was compared with theoretical dimensionless fluid temperature calculated by quasi-three-dimensional model for both single and double U-tubes. Results show that the -p--linear dimensionless temperatures with parameters -p-→0 and -p-= -1/2 are respectively in good agreement with the theoretical dimensionless fluid temperatures of single and double U-tubes. Therefore, the dimensionless logarithmic mean temperature for -p-→0 and the dimensionless geometric mean temperature for -p-= -1/2 should respectively be adopted to reasonably estimate the thermal resistance of single and double U-tube boreholes.

Abstract:Based on the actual boundary conditions of indoor air environment, the characteristics of indoor source (VOCs) emission and sink effect were analyzed on the basis of the mechanism of building material emission and indoor surface sink behaviors in combination with CFD method. The selected factors reflecting indoor actual boundary conditions included the outdoor air quality of inlet, outdoor airflow, indoor air temperature and the area ratio of sink to source. The results have shown that the decline of inlet outdoor air quality and the increasing of outdoor airflow have opposite influence on indoor VOCs emission intensity and sink intensity, but the former may cause the mean concentration of indoor VOCs to rise and the latter may make it descend. Meanwhile, the impact of indoor air temperature on indoor VOCs emission intensity and that on indoor VOCs mean concentration have similar characteristics. This is also true of the effect of sink to source area ratio on indoor VOCs sink intensity and that on indoor VOCs mean concentration. In addition, it is an effective way to obtain the characteristics of indoor source emission and sink effect with the established source emission model, the sink model and the indoor actual boundary conditions.

Abstract:To solve the problems such as the distribution of fault diagnosis information and the difficulty of knowledge sharing and reuse, a model of ontology-based fault diagnosis knowledge management system was introduced. According to the characteristics of the knowledge resources for fault diagnosis, Structure Ontology (StrOnto), Testing Ontology (TestOnto) and Fault Ontology (FaultOnto) were constructed. The fault tree generation algorithm based on the connection of heterogeneous ontologies was put forward to achieve the goal of knowledge sharing and reuse. An ontology-based fault diagnosis knowledge management system of 4L-20/8 two-stage air compressor was established. This system can provide more precise knowledge retrieval and diagnostic decision-making services for business users. It can also provide conditions for intelligent equipment maintenance.

Abstract:In order to appropriately deal with the connection problems in kinetic analysis such as shell-beam-bar, superposition plates, beam axis-spring, shell-spring, shell-solid connections, et al, in high speed railway's slab track, Timoshenko's shell theory and direct introduction method were applied to establish multi-point constraint equations and the calculation model of the composite slab track. In the composite structure, to solve different type elements' revision to the composite structure's total matrix caused by the elements' offset connections, the multi-point constraint equations on the basis of both the linear hypothesis in shell theory and eccentricity relations among relative nodes pairs in the composite structure were introduced to Galerkin weak form. The reliability of the FEM model on the basis of Timoshenko's shell theory and direct introduction method was proved by the comparison between numerical analysis and real measured results, and meanwhile, the model produces good connections among different layers in the structure, eliminating irrational additional stress generated in conventional methods, which improves the connection problems among different components in FEM analysis.

Abstract:Presented in this paper is the energy flow distribution of a diesel engine turbocharged system, on the basis of a combined method of one-dimensional gas dynamics simulation and dyno tests. By analyzing the flow path of exhaust gas energy flow from turbine to compressor and then intercooler, the exhaust gas energy recovery potential by turbocharging was obtained, and the energy flow characteristics in the diesel engine turbocharged system was analyzed. The results have shown that the energy recovery potential is strongly dependent on the engine's and the turbo's operational conditions. About 13% of engine exhaust gas energy could be recovered by the turbocharger when the latter works in the high efficiency domain, while only about 6% could be recovered in the low efficiency domain. Under all operational conditions, around 2% of the recovered exhaust gas energy is used to boost the intake gas pressure, and the rest is taken away by the intercooler. The results have provided theoretical basis and fundamental data for engine fuel saving through exhaust gas energy recovery by turbocharging or turbo-compounding.

Abstract:Based on the theory of tire cornering and tire force research, the effects of load re-distribution on the tire cornering characteristics and the effects of side angle on the vehicle steering characteristics were analyzed. Some adjustments were made to Ackermann theory based on the actual situation, and the contrast shows that this method can reduce the error of the design and the actual situation. Finally, the steering wheel system of 220t electric mining truck was optimized by experiment, which can significantly improve the vehicle steering system and vehicle motion characteristics performance.

Abstract:A new method for extended target radial velocity estimation was presented for high pulse-repetition -frequency (PRF) up-down stepped-frequency (SF) linear frequency-modulated (LFM) pulse radar with hypersonic missile-borne application. This method firstly achieves the ambiguous estimation of target radial velocity by the range difference caused by range-Doppler coupling between range profile segment of up frame and down frame, then achieves unambiguous estimation by using quadratic phase term compensated and velocity matched correlation between the range profile segment of the two frames. Theoretical analysis and simulation results have shown that this method has the advantages of wider range of unambiguous velocity measurement and less computation in velocity searching and matching, compared with the traditional methods.

Abstract:In order to eliminate the pores and shrinkage porosity in the casting aluminum silicon alloy, and improve the microstructures and the mechanical properties of the alloy, large size Al-Si alloy pipes were prepared with gravity casting. A new wedge pressing process for compressing large scale porous tubular performances was adopted on the basis of the idea of accumulating local small deformation as to integral forming. The rule of the wedge pressing process and microstructures and the mechanical properties of the alloy were investigated with hardness tests, tensile tests and SEM. The results have shown that the wedge pressing process can markedly eliminate the pores and shrinkage porosity in gravity casting performances. The coarse primary silicon was crushed, and most of the eutectic silicon was refined and distributed uniformly in the matrix. The mechanical properties and density of the gravity casting increased from 112 MPa, 1.2% and 2.48g/cm3 to 203 MPa, 5.2% and 2.68g/cm3 respectively after the reduction of 40%.

Abstract:MoSi2/R-SiC composite were obtained with different amount of MoSi2 in the SiC mixture powder and then sintered at 2 300 ℃. The XRD, SEM and impedance analyzer were used to study the microstructure, composition and volume resistivity. Experiment results showed that the 6H-SiC and Mo4.8Si3C0.6 with hexagonal structure were the main composition in materials obtained. The formation process was liquid MoSi2 losing Si and transforming into Mo-Si-C compounds and then reacting with SiC. The SiC grain was coated with Mo4.8Si3C0.6 compound. With the increase of additives, the thickness of the Mo4.8Si3C0.6 coating on SiC particles increased, and finally filled in the porosity in composite when the additive exceeded 10%. The density and porosity of the material increased at the same time. The mechanical properties changed little but the volume receptivity decreased significantly. Finally, the electronic conductive mechanism of the materials was discussed.

Abstract:Owing to the difficulties of traditional anti-virus technologies against internet worms, more and more attention has been paid to anti-worm in the field of malicious code. Real-time hybrid confronting technology was presented to solve the shortcomings of the existing confronting technologies in confronting validity, resource consumption and the ability to handle accidents, which changes confronting tactic according to the radio of hosts infected by anti-worm to susceptible hosts. And the propagation model of real-time hybrid anti-worm was constructed. Finally, the performance of real-time hybrid confronting technology was validated by simulation experiments on confronting validity, resource consumption and ability to handle accidents. Analyses and experiments have indicated that real-time hybrid confronting technology is better than other technologies on confronting validity with low resource consumption, and can handle accidents.

Abstract:Error control is a basic technology to ensure multicast reliability. Reasonable buffer management can improve error control efficiency. This paper has put forward an improved reliable multicast protocol (IRMP) on the basis of randomized reliable multicast protocol (RRMP). IRMP used a short buffer to meet local recovery requirement, and used a long buffer to meet remote recovery requirement. In local recovery, the retransmission request was sent by multicast, and the randomized back-off algorithm was used to reduce repeat message. In remote recovery, a designated repair node (DRN) was responsible for the repair. In order to avoid the quit or default of DRN, this paper has put forward a method for DRN transfer. Simulation results for IMRP and RRMP in NS2 have shown that IMRP has good ability to reduce the buffer requirements and recovery latency, and also improves its scalability.

Abstract:An important facet of Last.FM and MovieLens is that users manually annotate the items using so called tags. There are many researches about using tag to improve the quality of recommendation. However, tags are “local” descriptions of items given by the users,because different people use different tags for the same item, but the tags may represent the same means. In this paper, we used tag grouping method to group the tag according to the similarity of co-occurrence distributions. Based on this, we proposed an approach to group synonymy tags and fusing the relationship between users-tag with the collaboration filtering algorithms. The results of the empirical evaluation show that the approach is effectiveness in augmenting recommendation.

Abstract:Based on the theory of investors' heterogeneous beliefs, this paper used a dynamic model to investigate the internal relationship between investors' heterogeneous beliefs, short-buy mechanism and stock market liquidity in downturn. It is confirmed that the investors' heterogeneous expectations for the economic recovery intensity will aggravate the deficiency of stock market liquidity in downturn, where the delayed purchase resulting from the “re-buy option” is a significant reason. Moreover, the model and numerical simulations have demonstrated that the introduction of short-buy mechanism will alleviate this shortage of liquidity and speed up the recovery of bear markets, which will provide valuable implications in the post-crisis times.