Abstract:In this paper, sum flow rate-damper signal and highest load ratio-minimum flow rate were presented to optimize the supply air static pressure and the temperature of Variable Air Volume (VAV) system. This scheme was applied to the VAV system of a building. The models of VAV system were established, and TRNSYS was used to stimulate the duct system of the typical floor. The models were certified with measurement data. The energy consumption of VAV fan before and after the optimization was stimulated on typical days. The stimulation results show that, compared with constant static pressure and constant air temperature control scheme, the original one, the optimal scheme can save the energy consumption of Air Handling Unit (AHU) fan, especially in part load situation. The energy saving ratio reaches 19.38% and 15.58% on the test days of winter and transition season, respectively. Experiments were conducted to compare the whole year energy consumption and the indoor thermal comfort with two schemes. The results show that the whole year energy saving ratio reaches 7.16%. Indoor thermal comfort is improved remarkably.

Abstract:Prestressed concrete girderless roof under solar radiation and seasonal temperature difference is likely to crack．In order to study the mechanism of cracking，two finite element analysis models of the roof were developed with the finite element software ABAQUS．Their stress distribution nephograms were obtained．The results show that this kind of roof generally cracks near the fascias under solar radiation，and the cracking direction is parallel to the edge of the fascias or is perpendicular to the diagonal line of the fascias，while under seasonal temperature difference，the roof generally cracks near the post-pouring strip，and the cracking direction is parallel to the edge of the fascias and the cracks may be penetrating．

Abstract:In order to obtain the critical load position of continuously reinforced concrete pavement (CRCP), a three-plate system was established to calculate the pavement stress. In view of the design principle of the dowel steel in the jointed concrete pavement, the load transfer stiffness of the steel bar at the position of CRCP transverse crack was introduced. And then, the finite element method (FEM) was adopted to deduce the formula of the load transfer stiffness of the concrete at the position of the CRCP transverse crack. These two kinds of stiffness were the key parameters to the stress calculation of CRCP under wheel load pressure. On this basis, a numerical simulation was conducted, and the results have shown that the boundary condition will exert no effect on the load stress calculation when the length of the side plate exceeds 4.0m. Besides, for the two-lane pavement, the maximum load stress along the width is located at the bottom of the left lane, outside the center of the wheel track, while the standard wheel loads exist at the edge of the pavement, as well as close to the transverse crack. The position can be used to check CRCP load capacity.

Abstract:A model test was carried out to study the macro-micro mechanism of the debris flow prevention by using “anchor-slope protection”. The experiment result indicates that the exudation amount of rain water leads to pore water pressure increase, retrogressive toe sliding is not found during the experiment, and the experimental slope has infiltration softening and small-scale peristalsis. The micro-analysis indicates that the water-soil movement in slope has two forms, “water seepage among particles” and “fine particle float in water”, and the fine particles drop down with seepage water and float among grain skeleton with flowing water. As last, the fine particles were accumulated at the base of slope at the work of “anchor-slope protection”. Macro-micro experimental analysis indicates that particle micro-movement changes the structure of the slope as the relative stable structure of “fine particle drop to the bottom and compaction, the upper coarse particle skeleton is stable” is formed, and this stable structure reduces the incidence of debris flow.

Abstract:By using fractal theory, the analysis of the particle size distribution of the slacking products of red beds soft rock in nature environments shows that the slack process tends to stagnate when the fractal dimension value reaches the interval of 2.6~2.7. After analyzing the crushing ability of hydraulic breaking hammer and sheep-foot roller on red beds soft rock, the mechanical crushing technology to aim at eliminating the slacking properties of red beds soft rock was proposed. The core of this technology is “milling and compressing” action, which is based on the unique iteration character in the process of creating a fractal figure. On-site experiments on the technology were conducted subsequently on Liu-Li Expressway. Calculation results of the fractal dimension value on the particle size distribution data of soft rock material show that 2 times of “milling and compaction” action can crush the red beds soft rock to the extent that its fractal dimension value can reach the interval of 2.6~2.7. The results verified the mechanical crushing technology developed based on the fractal iteration character, which could eliminate the slacking properties of red beds soft rock. The crushing technology has been applied in the expressway construction process and can extend the application of red beds soft rock material from the lower embankment to the upper embankment.

Abstract:This paper presented the theoretical solutions and the experimental tests of the deformation processes of the inner core constrained by flexible sleeve in a sleeved column, and proposed the design formulas, relevant details and the nonlinear computation model of inner core's axial load-displacement. The results indicate: (1) when the stiffness ratio between the inner core and the sleeve is smaller than 0.005, the inner core will snap from low order mode to high order mode; when the stiffness ratio is larger than 0.005, the inner core and the sleeve will buckle together laterally; (2) the stiff sleeve, small slenderness ratio of the inner core and the large net clearance between the inner core and the sleeve exert adverse effects on the remarkable improvement of the inner core's bearing capacity; the parts of the inner core outside the sleeve are most vulnerable, their length must be small and the parts must be strengthened to avoid the local buckling of the inner core; and (3) compared with the conventional circular steel tube, the compression capacity of the inner core has been improved substantially and its ductility has also been greatly improved.

Abstract:Series tests were carried out for the new airship envelope fabric Uretek3216L. First, uni-axial cyclic tests were conducted. And then, on the basis of the multi-function bi-axial tension tester developed in SSRC, bi-axial tension tests with five stress ratios were carried out with particular test protocol. Detailed experiment results and elastic modulus and Poisson's ratio were obtained. The stress-strain relationship and elastic modulus of the membrane material under uni-axial tests and bi-axial tests were obtained at different cycle numbers. Moreover, the relation formula between coupled elastic modulus and stress ratios was proposed and bi-axial stress-strain surfaces were presented. The results have shown that, for the uni-axial cyclic tests, from the 1st to the 15th, the elastic moduli increase by 20.7% in warp and 39.1% in weft of the initial elastic modulus respectively; and the 2nd cycle has the biggest increments in both directions, which are about 60% of the total increment in relevant direction. For bi-axial tensile tests, when the stress ratio increases, the warp direction's coupled elastic moduli increase and the weft direction's decrease gradually.

Abstract:Considering that the load weight changes can affect the performance of vibration isolation, an adjustable nonlinear pneumatic vibration isolator with the favorable characteristic of quasi-zero stiffness (QZS) was established. The QZS isolator was devised by connecting a vertical double-chamber adjustable pneumatic spring with four symmetrical initial horizontal single-chamber adjustable pneumatic springs. Analytical result revealed a unique relationship between the design parameters of pneumatic springs of the QZS systems. The adjustable QZS isolator could maintain the characteristic of quasi-zero stiffness by adjusting air pressure when the mass loading changed. In vibration analysis, the force transmissibility derived by the harmonic balance (HB) method was used for the performance evaluation of the vibration isolation systems. The adjustable QZS isolator outperforms a corresponding linear system, especially in low-frequency vibration isolation performance.

Abstract:To obtain the pendulum parameter values under specified conditions, analogical analysis was used to derive the relation between shuttle length and liquid sloshing frequencies, and hypothesis and analogical analysis were combined to derive the relation between rod quality and liquid sloshing force. Then, FLUENT was utilized to simulate the liquid free oscillation under different original conditions, and the simulation results were used to draw the fitting functions of pendulum parameters about tank shapes and liquid fill levels. The roll moment obtained from FLUENT simulation and pendulum numerical computation has shown that the method proposed is quite useful and the relative errors between parameters fitting results and the actual ones are all in the range of ±4%.

Abstract:Deep sea bed mineral coarse particle slurry flow was investigated in lift pump. Based on the new type of coarse particle-homogeneous slurry flow model, simulation to the two-stage lift pump in the solid-liquid two phase turbulent flow was conducted by using the fluid dynamics software CFX , and simulation results of solid-liquid flow characteristic in the pump and pump characteristics were obtained. Numerical simulation results verified the characteristic of two-stage lift pump.

Abstract:To address the design and optimization of Networks-on-Chip (NoC), a multi-FPGA based NoC emulation platform was proposed to speed up the functional verification and performance evaluation of NoC. By introducing hierarchical design approach and distributed traffic manager, the system flexibility is effectively improved while accelerating design space exploration (DSE) of NoC. The experiment result shows that the proposed emulation platform not only has a speedup of 500~10 000 times compared with classic software-based simulation method, but also outperforms other NoC platforms in emulation speed.

Abstract:Flower-like ZnO was synthesized in a simple chemical bath method. This ZnO structure modified by a controllable density of Au nanoparticles with an average diameter of 40 nm was achieved with hydrothermal process. The Uv-vis adsorption spectra of Au nanoparticles shifted a little, indicating the interaction between ZnO and Au nanoparticles, which led to excellent gas sensing performance. ZnO modified by Au nanoparticles with weight percent of 6 % showed that the optimum gas response to acetone and the gas response was nearly 17 times higher than that of pure ZnO.

Abstract:By adding different content of trace Bi and adjusting the content of residual rare earth, the effect on the microstructure, tensile strength, elongation, hardness and -40 ℃ low temperature impact toughness was studied. The results showed that, for 180 mm ×180 mm×200 mm specimen, adding 0.012% Bi could obviously eliminate the chunky graphite. But for 250 mm×250 mm×300 mm test block, adding trace Bi could only inhibit chunky graphite to a certain extent. With the increased amount of Bi, the inhibition of chunky graphite enhanced at first and then weakened, with the best value between 0.010% and 0.012%. Meanwhile, the value of tensile strength, elongation and -40 ℃ low temperature impact toughness was 337 MPa, 10.4% and 10.5 J, respectively. Reducing the content of RE and making wRE /wBiadd =1.3~1.5 could further reduce the chunky graphite and improve the comprehensive mechanical properties.

Abstract:The effect of annealing temperature on the microstructures and mechanical properties of the cold-rolled Fe-25Mn-3Al-3Si TWIP was studied by means of electron backscatter diffraction technology, transmission electron microscope and tensile test. The Hall-Petch relationship was analyzed in detail. The results have shown that the microstructure of the fully recrystallized samples consists of equiaxed grains and annealing twins. With the increase of the annealing temperature, the grain size is continuously increasing while the fraction of Σ3 grain boundaries is fluctuantly increasing. After annealed at 850 ℃ for 1 h, the Σ3 grain boundaries reach 44%. In the tensile process, the relationship of strength and grain size obeys the Hall-Petch relationship, but twin boundaries affect the slope K of the Hall-Petch relationship. The K(ε)-ε relationship of the TWIP steel is different from that of general steels at room temperature, in which K(ε) monotonically increases with the strain ε. The K(ε) of the TWIP steel increases first, then, keeps unchanged and finally decreases with the strain ε.

Abstract:In order to develope a new coumarin-strapped calix［4］pyrrole molecule fluorescent probe for anions, a series of coumarin-strapped calix［4］pyrrole compounds 6~9 was synthesized by coupling meso-heptamethyl-meso-p-aminophenyl cali［4］ pyrrole 1 with coumarins acids 2~5 under the catalysis of DCC/DMAP or the amidation of acyl chloride. 1 was synthesized by using p-aminoacetophenone, acetone and pyrrole as the starting materials and HCl as the catalyst. 2~5 were synthesized through Knoevnagal reaction and hydrolysis, with 2-hydroxy-1-naphthaldehyde,4-(diethyl) aminosalicylaldehyde, salicylaldehyde, 4-methoxy salicylaldehyde and diethyl malonate, and piperidine as the starting materials and acetic acid as the catalysts. Among the synthesized compounds, 1 and 6~9 were new compounds. The structures of the synthesized compounds were characterized by 1HNMR, MS and elemental analysis.

Abstract:To analyze the best conditions for different types of mutations required in error-prone PCR system, this paper tried to process error-prone PCR by adding different concentrations of manganese(0.125，0.250 and 0.500 mmol/L) into normal PCR system. Different lengths of DNA fragments of S.cerevisiae spt15 (about 200,500 and 700 bp) were amplified to study their mutation ratios, spectrum of mutations and the distribution of base substitutions. The results have shown that the error-prone PCR mutation rate of longer fragment DNA is more sensitive to manganese ions concentration. The mutation number of bases has a significant impact on the length of template DNA. Lower manganese ions concentration is conducive to a single mutation. The base substitution distribution of mutation driven by manganese ions has obvious bias towards the transition of A → G and T → C.

Abstract:In video surveillance systems, noise and shake of the background caused by complex environment can greatly influence the detection of moving objects. In order to solve this problem, a Gaussian Mixture Model (GMM) based on subzone gray projection video stabilization algorithm was proposed. First, each frame was divided into several blocks, and the subzone gray projection algorithm was applied to the frame to exactly extract the motion vector of each subzone and analyze the correlation between them. Based on the above analysis, we could decide whether a frame was with dithering or not, and make motion compensation for dithering frame. Then, we used GMM algorithm to extract the moving objects. Finally, morphology was applied as post-processing to further improve the detection accuracy. The subjective and objective evaluations of many different videos were implemented to verify the validity of the proposed algorithm in our experiments. The experiment results have shown that the proposed algorithm can detect the moving targets accurately from the scenes with dithering and suppress the false alarm rate significantly.

Abstract:Material plant management is the core of iron and steel enterprise management, and storage location choice is the key of material plant management. To solve the problem of storage location choice, an optimization criterion of storage location was establised in order to improve material plant utilization and raw material ingredient stability. Furthermore, triangular fuzzy number and AHP were used to build a new kind of storage location optimization model. The results have shown that the optimization model can significantly improve material plant utilization and raw material ingredients stability, which has promising applications in industries.