Abstract:Design method of stress increment in unbonded tendons and moment redistribution in codes as GB50010、JGJ92 and ACI318 were mainly applied to linear members. The investigation of stress increment in unbonded tendons and the inner force redistribution of prestressed concrete edge-supported two-way slabs is few. Therefore, the finite element was modeled by ABAQUS soft-ware for unbonded prestressed concrete edge-supported two-way slabs, and the stress increment in unbonded tendons and moment redistribution of prestressed concrete edge-supported two-way slabs were studied, which were influenced by the grade of non-prestressing reinforcement and combined reinforcement index in critical section of support. It is shown that at serviceability state the stress increment in tendons increases with the higher combined reinforcement index and higher yield strength of non-prestressing reinforcements. At ultimate limit state the stress increment in tendons increases with the lower combined reinforcement index and higher yield strength of non-prestressing reinforcements. The moment redistribution coefficient reduces with the higher combined reinforcement index and higher yield strength of non-prestressing reinforcements. Calculation formulas of stress increment in tendons and moment redistribution coefficient in critical section of support are proposed, which provides basis for design of unbonded prestressed concrete edge-supported two-way slabs.

Abstract:To investigate the hydroxyl radical (OH·) formation during ozonation, OH· yields (Φ) in the reactions of O₃ with O₃ reactive compounds such as electron-activated aromatic compounds and amines were determined by the “tBuOH· assay”. In addition, the Φ values in the ozonation of waste water effluent, surface water and groundwater were investigated. The results showed that the Φ values in the reactions of aromatic compounds, amines and olefins with ozone were in the range of 10％-30％, 15％-35％ and 0, respectively. The Φ value was about 41％ in the reaction of hydroxyl ion (OH-) with ozone. Competition of OH- with water matrix for O₃ consumption resulted in lower Φ value in waters with higher content of DOC. Generally, the Φ values were in the trend of groundwater> surface water> waste water effluent.

Abstract:To improve the re-growth ability of broken flocs and the removals of colloids and small particles, the raw water with character of low temperature and turbidity was investigated using optical detection instruments and mathematical method. The effects of additional dosage of PAC on the variations of the floc size, growth rate and floc size distribution were studied and the removals of turbidity and particles were also conducted. With the increase of PAC dosage, the floc size and growth rate showed an initial upward trend followed by a downward trend, and the optimum dosage for the floc size and growth rate was 4 mg／L and 6 mg／L, respectively. Moreover, the residual turbidity and particles were significantly decreased first, and then increased. The lowest values of residual turbidity and particles were 0.79 NTU and 90 mL-1. When the addition dosage was 2 mg／L, the volume percentage of the flocs in the range of 280-630 μm was evidently increased from 22.85 ％ to 46.36 ％, while that of the flocs in the range of 4-35 μm was decreased from 1.21％ to 0.19％. In addition, the floc size after re-growth was 400 μm, larger than that before breakage, with the growth rate of 77.26 μm／min. Therefore, the additional dosage of PAC could obviously improve the re-growth ability of the broken flocs and the removals of turbidity and particles. Moreover, the experimental results could effectively improve the treatment efficiency and water quality.

Abstract:The aim of our study is to estimate the effects of inoculation with arbuscular mycorrhizal fungi and fertilization on rice quality. Rice quality was estimated for inoculated and non-inoculated rice grown in both fertilized and non-fertilized paddy fields. It was found that in non-fertilized paddy fields there was a negative effect of inoculation on rice processing and appearance quality but no significant effect on cooking, tasting and nutrition quality. In addition, fertilization improved rice processing and cooking quality whereas no significant effect was found on appearance, tasting and nutrition quality. Finally, the interaction between inoculation and fertilization improved appearance, cooking and tasting quality and guaranteed the Fe and Zn content of rice. In conclusion, interaction between AMF inoculation and fertilization plays a vital role in improving rice quality.

Abstract:To analyze the effect of underlying surfaces on local thermal climate, this paper took the international low-carbon city of Shenzhen as an example, and the effects of different underlying surfaces on the urban heat island (UHI) and outdoor thermal comfort were discussed by using multipurpose regional thermal climate prediction model. The results showed that the maximum urban heat island intensity(UHII) reflected the temperature difference between urban and suburban of the hottest cases while the average local UHII reflected the average difference of the whole day. And the average local UHII of night was higher than the average local UHII of daytime. Besides, the cooling effects of water and trees were better compared with other natural underlying surfaces, while appropriate increase of grass coverage could more effectively improve the outdoor thermal comfort.

Abstract:To study the building anthropogenic heat emission law and outdoor atmospheric dynamic thermal balance in urban complex which has multiple functions, an urban complex thermal climate dynamic prediction model is developed and applied to an actual planning project in Shenzhen. The results show that the heat release from building happens in most of the time of a typical calculation day, and the heat release law follows the operation law of the corresponding type of air conditioning refrigeration system. During the whole calculation period, the building anthropogenic heat accounts for the largest proportion of the total heat released, which is about 62.1％. The heat island intensity daily average value and maximum value in the whole calculating period of the urban complex area is 0.1-0.45 ℃ lager than that of the common urban area with a single building type. The above results suggest that the anthropogenic heat discharge from building is one of the main factors for the formation of hot and wet climate in this urban complex area.

Abstract:In order to improve energy saving efficiency of Harbin residential building, we select optimizing southern windows’ size to improve sunshade efficiency as research purpose, appropriate glazing floor area ratio of should be confirmed within the specification limitation according to Harbin’s climate. By controlling the southern windows’ area, height and width, wall thickness and visor width, energy saving efficiency can be improved by preventing direct solar insolation in summer, which can reduce the cost of room temperature refrigeration, without reducing solar insolation in winter. The energy-saving efficiency will be maximized by software simulation analysis, and the southern window normative design patterns is formed. Through calculating receiving heat of ground energy saving effect of the optimized southern window can be verified.

Abstract:Methods such as field investigation and statistical analysis were used to analyze the characteristics of auxiliary through lane (ATL) at signalized intersection. Variation of traffic volume, headway of vehicles, lane utilization ratio and types of accidents were chosen as the characterization parameters and the traffic operation characteristics of ATLs were analyzed. Results show that the ATL plays an important role in enhancing the operational capacity of signalized intersection, but the headway of vehicles driving on ATLs has obvious characteristics of "two stages", low lane utilization rate and more scratch accidents. Means like traffic sign layout improvement measures, transition section, sight distance and downstream length should be applied to improve traffic operation conditions of ATL.

Abstract:To bring insight into the non-motor vehicle’s riding behavior mechanism influenced by curb parking, judgment criterion of serious traffic conflict between non-motor vehicle and vehicle (STCNV), non-motor vehicle’s averting danger behaviors and the probability distribution model of the STCNV were put forward and studied based on the survey data on scene. Firstly, non-complete braking distance was presented as the judgment index of the STCNV; the data of traffic conflicts and non-motor vehicle’s averting danger behaviors was collected at the curb parking area; and the deceleration behavior was concluded as the main averting danger behavior. Then, the Poisson probability distribution model of the STCNV was constructed; the safety judgment model for non-motor vehicle’s riding and its critical value calculation standard was proposed on the bias of the Normal distribution, and the safety evaluation was implemented for the survey sections.

Abstract:To avoid the collision between end-probe and space robot carrier or the spacecraft to be tested, 3D simulations are required for trajectory planning method of end-probe before the actual on-orbit measurement. In view of the nonvisual problem of the existing simulation system of space robot, a 3D simulation system based on virtual reality technology is designed. First, 3D solid model of space robot is established based on Open Inventor, and the 3D scene of space robot logical location is set up. Then, the visual 3D simulation system of space robot is created based on the data transmission technology and 3D scene. Finally, the kinematics model of space robot is established and the circular trajectory of the space robot end-effecter is planned. Simulation results indicate that the motion process of space robot and the motion characteristics of the space robot base can be obtained visually. This system facilitates the simulation study on the method of space robot trajectory planning and control, and avoids the collision of space robot due to improper trajectory planning.

Abstract:The circuit parameters of Buck-Boost converter with switched-inductor are studied in order to analyze the influence on the performance of the system. The discrete iterated mapping model under discontinuous conduction mode (DCM) is established. The stability problem is studied by bifurcation diagrams and Poincare sections, and the location of the first bifurcating point is confirmed based on the loci of eigenvalue for the system’s Jacobian matrix. Finally, a simulation model is built up by PSIM software to verify the correctness of the theoretical analysis and the rich dynamic process is observed by time-domain diagram and phase track diagram under different parameters. The studied results and analysis methods are helpful for designing and debugging the switched converters like that. The results show when Buck-Boost converter with switched-inductor works in DCM mode, its working states are mainly affected by the border of current I_b2, the current I_b1 border has small impact on the stability of the system. With the change of circuit parameters, the system enters into DCM intermittent chaos state by the border collision bifurcation.

Abstract:To investigate the inhibitory effect of polysaccharides from corn bran extracted by three different methods on the HT-29 cells, it was studied by MTT assay, inverted microscope, mitotic index and colony formation. MTT results showed that the water extraction polysaccharide from corn bran had a significant inhibition effect on the proliferation of HT-29 cells in a dose-dependent manner. After treatment for 48 h with 0.02 g／L of water extraction polysaccharide from corn bran, the inhibitory rate was 60.62％. The other two polysaccharides had no affect on the growth of HT-20 cells. The morphologic observation showed that the water extraction polysaccharide from corn bran induced obvious morphological changes. The mitotic index and colony formation was decreased compared with the control group as the incubation time and concentration of water extraction polysaccharide from corn bran.

Abstract:The voltage generator equipment is not conductive to resist horizontal seismic actions and strong wind actions for its large slenderness ratio, high center of gravity and low damping ratio. To study the damping matrix models in seismic response analysis of the generator, the dynamic characteristics of a twin-tower voltage generator were analyzed under the excitations of three waves (Taft wave, El-Centro wave and Ninghe wave) with six different Rayleigh damping modes. The results show that the selection of damping coefficients has great influences on the calculation accuracy of structural dynamic responses. As the damping coefficients are determined by the two natural frequencies of vibration, it is wiser to take both characteristics of seismic spectra and structural natural vibration properties into account when choosing the damping coefficients, so that the calculation results will be more accurate.

Abstract:Comparison of the treatment effect and mechanisms of different preoxidants on algal cells were analyzed by the experiments of inactivation of M. aeruginosa with potassium permanganate, ozone and sodium hypochlorite. The results showed that the decrease of quantum yield of M. aeruginosa caused by chlorination and ozonation both followed second-order kinetics. Sodium hypochlorite caused the cell lysis with the quantum yield rate constant of (220±3) L·mol-1·s-1 and resulted in the release of intracellular organic matter(IOM) regardless of initial concentration. Ozone had a profound oxidation effect on M. aeruginosa cells and would rapidly cause the cell lysis with the rate constant of (2 655±15) L·mol-1·s-1regardless of the initial ozone dosages. The sequence of the quantum yield rate constants of three oxidations was O₃>NaClO>KMnO₄. However, both ozone and sodium hypochlorite caused the cell lysis and led to the release of IOM more easily than potassium permanganate, which was suggested by the results of scanning electron microscopy.

Abstract:To enhance the simultaneous removal of nitrogen (N) and phosphorus (P) of low C/N (P) ratio sewage by A²/O technique, and ensure the effluent meet the first class level A standard of GB18918—2002, two patterns of A²/O technique were conducted to treat the experimental sewage. Pattern 1 was the A²/O technique with the carrier, under the optimized conditions of tHR=8.2 h, R=80%, r=250%-300%, ρ(DO)=1.5-0.5 mg/L, the concentration of TP in effluent of the system still exceeded the standard. Pattern 2 was the improved pattern 1— terminal intermittent aeration A²/O technique with the carrier, which contained an intermittent aeration zone following the aerobic zone, meanwhile, the approaches of sludge return and discharge were changed. The novel system with the long tSR of 22.3 d ran at the conditions of the optimal operating modes above-mentioned for A²/O zone, tHR=4 h for the intermittent aeration zone, and the aeration cycle was 1 h: aeration time was 1 min (ρ(DO)=0.3-0.5 mg/L) and settling time was 59 min. The operational results showed that the average removal rate of COD, NH₄+-N, TP and TN reached 87.8%, 99.1%, 95.5% and 90.8%, respectively. The nitrosation rate of the effluent was above 70%, and DPAO/PAO ratio in sludge was 95.65%, the final effluent of the system met the first class level A of the national standard through the pathway of shortcut nitrification and denitrifying nitrogen and phosphorus removal.

Abstract:To investigate the effect of manganese intermediates in situ formed on the oxidation of anti-biocide triclosan by potassium permanganate, experiments were conducted to examine the effects of some ligands as well as Mn(II) on the oxidation of triclosan by potassium permanganate under the condition with potassium permanganate in excess over a wide pH range. The results showed that the degradation of triclosan followed the second-order kinetics and the rate constants increased with the increase of pH and reached the maximum near the pK_a (8.1) of triclosan, after which they decreased gradually. Both selected ligands and the background matrices of nature waters could significantly enhance the oxidation dynamics of triclosan by potassium permanganate via the involvement of stabilized manganese intermediates. The analysis by the UV-vis spectrophotometer scanning confirmed the formation of soluble Mn(III) in the presence of ligands, which would otherwise disproportionate spontaneously to yield solid MnO₂. Also, these results suggested a catalytic role of Mn(II) in the oxidation of triclosan by potassium permanganate.

Abstract:Based on the deficiencies of existing ground heat exchangers, a new type energy-storage heat exchanger is proposed, which consists of three inlet pipes and one thermal insulation outlet pipe. Thermal resistance of this new type heat exchanger is calculated, which shows a much smaller value over conventional ones. Experimental measurements to evaluate the performance of single-U, double-U and the new design, were carried out in boreholes about 96 meters deep, which showed superior performance of the new type. The thermal resistance of the new type was 29%-34% and 10%-15% smaller than that of single-U and double-U respectively. The circulation water temperature rise of new type was 1.5 ℃ lower than double-U.

Abstract:To solve the problem that the dust concentration exceeds on the rock comprehensive tunneling face, the dust fall plan is established according to comparative analysis for improving working environment. On the background of belt transport lane in the south of Xue village mine, the discrete phase model (DPM) for computational fluid mechanics is used for numerical simulation of dust movement rule on rock comprehensive tunneling face on the basis of the gas-solid two phase flow theory. In contrast to the field measured data, the simulation result almost conforms to the measured data. The study found that, after dust source generated, the dust moves with air flow direction on vertical, random diffuses along the merry tangential direction on transverse. The frictional dust concentration in roadway drivage rises sharply to maximum, then gradually slows down. In comprehensive dust fall scheme, the order of the dust fall effect, according to quality, is: both installation at the same time, installation of mural ram, installation convulsions shaker system, press in type ventilation. According to the measured data, taking the press condition ventilation as reference, the average removal rates of installing air duct, installing dust collector and installing the two at the same time are 49.4％, 67.1％ and 86.2％, respectively.

Abstract:A new predictor-corrector methodology is developed for hypersonic vehicles with multi-constraints including typical inequality constraints, terminal states and no-fly zone. The approach makes use of the quasi-equilibrium glide condition (QEGC) for converting typical inequality constraints to the constraints of bank-angle, which is parameterized and found online with predictor-corrector in longitude guidance. Lateral guidance converts no-fly zone constraints to the range of velocity azimuth angle in real time and combines with the strategy of error corridor compensation for forming a new heading error corridor, which is used to avoid the no-fly zone. The algorithm does not rely on a standard trajectory and the guidance commands are calculated in real time, which endows the algorithm with sufficient adaptability. The simulation results show that the algorithm leads the vehicle to avoid the no-fly zone successfully while satisfying the terminal and path constraints, and has high guidance precision and robustness.

Abstract:The grid algorithm is an attractive one in star identification algorithms. However, this algorithm needs at least 6 stars in sensor image, which limits its application to the stellar sensor whose field of view (FOV) is small or stellar magnitude limit is low. To break this limitation, a new algorithm named extended grid algorithm in star identification field is proposed. The ideas of the new algorithm is the combination of extended image algorithm and the grid algorithm, which can extend the FOV effectively, and then more stars will fall into the extended FOV. Additionally, the new algorithm inherits the advantages of grid algorithm, and its performance such as the stability and identification rate will be better than the extended image algorithm. To verify the performance of this new algorithm, a simulation according to the real situation is carried out. The results indicate that the star identification success ratio of the proposed method is larger than 97.4％, it is better than the traditional extended image algorithm, and the neighbor star identification success ratio of the proposed method can reach 86.7％ which is also better than that of the traditional grid algorithm. Therefore, the proposed method is more applicable for the small FOV or low limiting magnitude stellar sensor.

Abstract:To avoid the rolling stone hitting on bridge piers, a new anti-collision rigid structure design was proposed. First, a fine simulation methodology for simulating the collision between the rolling stone and anti-collision structure was given using the nonlinearity, contact algorithm, and constitutive relation in the dynamics theory, and the key parameters in this simulation were suggested. Then the entire collision process was analyzed by ANSYS／LS-DYNA program, and the simulation stabilization was verified from the system energy viewpoint. Finally, a design criterion of this anti-collision rigid structure for bridge piers was built in terms of damage-released energy and energy conversion efficiency. Based on the results the proposed simulation methodology shows its good feasibility and rationality and the expected anti-collision effects of such structure are proved.

Abstract:To stabilize high skid-resistant performance of EACCP, a method is proposed based on digital image technology to analyze texture structure of exposed-aggregate surface. By regulating digital image captured process of asphalt pavement surface, the error of digital image information could be reduced. Texture structure features of exposed-aggregate surface are acquired by means of the digital image. The curved surface model of image pixel space is established to calculate texture depth of exposed-aggregate surface. Utilizing the basic theory of image morphology, the binary image representing texture structure distribution is quantitatively analyzed. Calculating characteristic values of convex regions include number, area and its area ratios. The convex area percentage of exposed-aggregate surface can be contained. The results show that the relationship between convex area percentage and the skid-resistant value of its texture structure is an approximate parabola curve. To achieve high skid-resistant performance, the convex area percentage should be controlled within ［0.5,0.43］. The texture depth should be controlled within ［0.58 mm, 1.05 mm］. The grading characteristics of coarse aggregate has a significant effect on quality level of exposed-aggregate surface. The exposed-aggregate surface with 4.75-19 mm coarse aggregate gradation possesses high skid-resistant performance.