Abstract:An experiment about circular steel pipes subjected to cyclic loading was designed to study the spatial hysteretic behavior and obtain the constitutive model of steel considering damage cumulation.The experimental device was applicable for three-dimensional loading.Five loading modes were performed on a total of 30 specimens with different cross sections and heights with consideration of different slenderness ratios and loading modes for the circular steel pipe.The spatial loading of the circular steel pipe was successfully simulated by optimizing the experimental device,and the hysteretic curves composed of loading and displacement as well as the strain curves of typical position were obtained.Results show that the experimental device can meet the need of the experimental accuracy for its good stability.The circular steel pipe has excellent hysteretic behavior and can keep good capability of energy consumption even at great displacement action.The study lays the foundation of the subsequent research on constitutive model about steel.

Abstract:Considering the shortages of traditional methods in calculating a large-scale and complex structure with multiple-point wind excitations,the random wind-induced response analysis of large-scale and high-rise structures based on pseudo excitation method is presented.The multiple-point fluctuating wind loads are changed into harmonic pseudo-excitation vector by using the pseudo-excitation method,then the expression of wind-induced response can be derived according to the stationary stochastic theory which can automatically take the space correlation of multiple-point wind-excitations into account.The highest building under construction in Shenzhen city,Jin-Ji Tower,is employed as a numerical example.Results show that this method exhibits high accuracy and efficiency,and it is valuable in the analysis of stochastic wind-induced response of real complex and high-rise tower structures.

Abstract:In order to improve the calculation method of creak width of concrete beams strengthened with CFRP sheet,based on the theory of bond-slippage,the calculation formulas for the crack spacing and width of concrete beam strengthened with CFRP sheet are derived,and theoretical calculation method for the crack width is presented,which is suitable for concrete and prestressed concrete beams strengthened with CFRP sheet.On the other hand,following the traditional idea of crack width of reinforced concrete structures,the influence coefficients considering the CFRP sheet and the bonded prestressing steel are introduced in the calculation formula of the average crack width l m.The influence coefficient δ f considering the CFRP sheet and the bonded prestressing steel is introduced in the calculation formula of crack width w m and the calculation formula of coefficient of uneven stress of steel bar ψ,and the corresponding semi-theoretical-semi-empirical formula is given.The calculation results in above two methods are in good agreement with the test results.

Abstract:In order to investigate the plastic design method of indeterminate encased steel box concrete beam (ESBCB),4 two-span continuous ESBCBs are tested,and then the distribution and growth of crack,deformation,failure characteristics and redistribution of plastic internal force are obtained.The calculation formula of the length of equivalent plastic hinge of ESBCBs is presented.A design method for moment modification is put forward,in which the object of moment modification is the difference between the elastic calculated moment of critical section at intermediate support and the moment subjected to the steel box when the composite beam reaching the limit state of bending capacity,and the variable is the relative plastic rotation.

Abstract:In order to investigate the plastic property of reactive powder concrete continuous beams,5 two-span reinforced reactive powder concrete continuous beams were fabricated,and were then tested with one point load applied at each midspan.During the test,the mechanical behaviors in the stage of cracks,yielding of the steel bar both in the critical section of intermediate support and mid span,and ultimate limit state were investigated.The calculation formulas of length of equivalent plastic hinge zone are presented based on the test data for the design state and the ultimate state.The calculation formulas of the moment modification coefficient with the plastic rotation of intermediate support and the relative height of compression zone as variables are presented respectively.

Abstract:An analytical stress-strain model for concrete cylinders confined by fibre-reinforced polymer (FRP) was presented to accurately simulate the behavior of FRP-confined concrete under uniaxial compression.Based on large numbers of colleted test data,a new equation for predicting the ultimate compressive strength of FRPconfined concrete circular columns was suggested according to the octahedral theory,and an equation for calculating the ultimate compressive strain was also proposed by considering the lateral confining pressure.The full-range lateral-to-axial strain relationship for FRP-confined concrete circular columns was obtained by analyzing the stress-strain curves measured in tests.Then an analytical stress-strain model was generated via an incremental process,in which a stress-strain model for actively-confined concrete proposed by Mander was used as the basic model.It is found that the predicting results agree well with test data.

Abstract:The combination of chromatogram and chemical analysis was adopted to optimize the methods selected to measure poly-P,glycogen and PHA intracellular polymer in EBPR system.PHA was measured by GC system,glycogen was degraded by dilute hydrochloric acid and analyzed by glucose commercial kit,and poly-P was oxidized by potassium persulfate and analyzed by molybdenum-antimony anti-spectrophotometric method.Testing of the proposed method for PHA analysis shows that 4% sulfuric acid concentration and degradation for 20 h are required for optimal PHB and PHV extraction,while 0.6 mol/L HCl and digestion for 5 h produce the highest recovery of glycogen,and the medical glucose kit can be used in this research.Oxidation for 30 min at 120 ℃ is recommended for the recovery of poly-P.The results of precision analysis and recovery test with standard addition of these methods show that they possess high precision and are convenient for laboratory research and practical application.

Abstract:A mathematical model on the preparation process of polysilicic acid (PS) was established to joint the bench-scale study with industrialization.Poly-silicic-ferric (PSF) coagulant was prepared using PS as semi-manufactured goods.PS was prepared using water glass and H2SO4 solution,and mathematical modeling concerning the relationship between gelation time (t) and such factors as pH value,initial w (SiO2) and temperature was presented.The influence of pH value on the species of PS with certain polymerization degree was explored.PSF coagulant was prepared using PS,FeSO4·7H2O and NaClO3 by co-polymerization.Both coagulation performance in treating lower temperature and lower turbidity water by PSF and characteristics of PSF were investigated compared with those of polyferric sulfate (PFS) and poly ferric aluminum (PFA).Results show that some PS is depolymerized after decreasing pH value when PS reaches a certain degree of polymerization,but the species after depolymerization differs from that at the same original pH value.PSF has higher coagulation efficiency than PFS and PFA.The mathematical modeling on the preparation of PS is the basic condition for preparing high quality PSF in industrial scale.The particular characteristics of PSF are just the essential reason for its superior coagulation performance.In the coagulation mechanism of treating low temperature and low turbidity water by PSF,charge-neutralization/destabilization is the precondition and the bridging is the necessary condition.

Abstract:To improve the regulation of energy-efficient operation and the hydraulic misadjustment for variable flow heat-supply systems,the dynamic hydraulic conditions and control strategies for the heat-supply network were investigated.The authors analyzed the control mode of circulating pumps with variable speed and the characteristics of pipeline network with pressure differential control for end user in a variable flow heat-supply system.Within the pressure difference and flow range of self-operated pressure differential control valves,the hydraulic operation characteristics of a heat-supply network in a variable flow heating system with users’selfcontrol were studied based on a practical case.The corresponding control strategies were put forward as follows:increasing the design value of pressure difference for end user,or changing the control point of the worst pressure difference,or monitoring the pressure differences of the critical users and fixing distribution pumps at these places.

Abstract:In order to solve the problems caused by the lack of energy source in the defrosting process of traditional ASHP,an energy storage based defrosting method for ASHP is presented and the corresponding experimental rig is developed.Experimental results show that the defrosting time can be decreased by 150 s,the suction pressure can be increased about 180 kPa,and the recovering time of heating supply is obviously shortened.It can be concluded that the developed defrosting method and the designed experimental rig are feasible.

Abstract:To reduce the influence of thermal effect produced during the charge process of natural gas,which can be used as vehicular fuel,a mathematical model of natural gas storage system was established and solved by algorithm of SIMPLER with the charge time of 60 s and 180 s.The results revealed that charge amounts were 2.138 9 kg and 2.172 3 kg for the charge time of 60 s and 180 s,the charge performance loss approached 45.15% and 44.29% compared with isothermal charge,and the average temperature rise of the system were 74.76 ℃ and 72.72 ℃,respectively.It can be concluded that the charge performance is adversely affected by thermal effect,so some measures must be taken to alleviate it.

Abstract:To determine the relationship between magnetic memory signal and working stress as well as residual stress,static tensile tests on plate specimens made of Q235 low carbon steel were performed.The variation regularities of normal magnetic field intensities on the surfaces of specimens with and without artificial defects under different working loads and after unloading were investigated respectively,using the magnetometer TSC1M-4.The test results show that there is a good correlation between the magnetic memory signal and working stress,and whether the specimen is in a certain critical or limit condition can be predicted via the correlation coefficient between two adjacent magnetic signals.The magnetic memory signals before and after plastic deformation after unloading can not be distinguished,but the fractured magnetic memory signal and the corresponding gradient curve have obvious characteristics to be used to identify fracture zones.

Abstract:The method of twisting the blade using a trailing-edge flap is presented in this paper.The dynamic model of the rotor blade with the trailing-edge flap is developed based on the modified Greensberg quasi-static aerodynamic theory.The effect of flap deflection on the torsion of the blade is investigated.Results show that the angles of torsion are equal to-3.8° and 3° when the flap deflection is 6° and-6°,respectively.The flap deflection has a powerful effect on the blade bending deformation in flapping direction.When the flap deflection is 6°,the tip flapping displacement is 0.16 R.It is decreased by 50.8% in comparison with that without any flap deflection.So it is feasible to twist the blade by using the trailing-edge flap.

Abstract:According to the essential characteristic of mechanical shields,a new inflatable shield was developed to settle the disadvantage of the existed shields,and its dynamic character was studied.The modal analysis of the inflatable shield was carried out by ANSYS.Factors affecting the inflatable structures were analyzed according to the theory of structural dynamics,and the principle of effects of structural dimension parameters on the modes of the configuration was obtained.It is found that the theoretical analysis agrees well with simulated results,and thickness and diameter of the inflatable pipe are main factors affecting the modes of the configuration of inflatable shield.

Abstract:In order to get the simulation models of organic materials in the molecular simulations,based on the model establishment of a single molecular chain using methods of "random walk" and "directional walk",a method to build the simulation cell of organic materials in molecular simulations is brought forward by adopting the principle of uniform distribution of all molecular chains in the whole cell.Then the cubic simulation cell with periodic boundary conditions and the nano thin film with free surfaces can be built by using this method simply.Two representative examples and the comparison of the obtained results with those obtained by other methods show that the proposed method is simple,convenient and reliable.

Abstract:In order to study the influence of friction on the thickness distribution of workpiece in superplastic forming,based on a TC4 deep cylinder with uniform side wall thickness achieved by direct-reverse superplastic forming,the influence of surface friction of preforming die and final forming die on thickness distribution was analyzed with MSC.MARC.Results show that increasing the friction coefficient of preforming die can efficiently reduce the thickness of the regions which need to be thinned,resulting in the final uniform thickness distribution along the component.Decreasing the friction coefficient of forming die can make the sheet tend to be integral formation,also resulting in uniform thickness distribution.According to the simulation results,the experiment on friction changing of direct-reverse superplastic forming was performed.The aerospace TC4 deep cylinder with uniform thickness of 1.50-1.78 mm was fabricated successfully.Compared to the thickness distribution of 1.18-2.24 mm of common direct-reverse superplastic forming,the thickness of friction changing is more uniform.

Abstract:In order to enhance the specific capacitance and energy density of carbon-based supercapacitor,some particles of nickel oxide were loaded into activated carbon.A hybrid type electrochemical capacitor was made and tested,in which the activated-carbon loaded with nickel oxide was used as anode material and activated-carbon was used as cathode material.Results show that the BET surface area of the activated-carbon decreases due to the deposition of nickel oxide,but no obvious change is found in the pore size distribution.The specific capacitance of the capacitor is increased from 175.40 F/g to 194.01 F/g.The potential of oxygen evolution on the composite material electrode reaches 0.296 V,and it is 0.076 V higher than that on the pure activated-carbon electrode,which indicates that the hybrid capacitor has high energy density.Similar to the pure activated-carbon electrode,no obvious change appears on the specific capacitances of the composite material electrode at various discharge currents and the composite material electrode exhibits good power characteristics.The operation voltage of the hybrid capacitor is 1.2 V in the electrolyte of 6 mol/L KOH solution,which is 0.2 V higher than that of double-layer capacitor made of activated carbon.It is concluded that the specific capacitance and energy density of carbon-based supercapacitor can be enhanced by loading some nanometer-scale particles of nickel oxide into activated carbon.

Abstract:To improve the effect of sentence-evel English audio segmentation,a method of sentence boundary detection based on dual-threshold is proposed.With consideration of the characteristics of normative waveform,small noise and stable speed for English audio such as VOA and BBC,the method in this paper detects the sentence boundary of English audio via its quiet energy threshold and quiet delay threshold,and the corresponding audio text is used to revise the segmentation result.Experiments on special English of VOA show that the recall rate of segmentation exceeds 96% and the precision rate exceeds 94% by using the dual-threshold method only.After revision via the corresponding text,the precision rate can be improved further.

Abstract:To solve the problem of peak clustering in Hough transform for track initiation of dim targets,an improved track initiation algorithm based on subtractive clustering is proposed.First,Hough transform is used to obtain the votes whose value exceeds the threshold in parametric space,and then a subtractive clustering method is applied to get the final result corresponding to the obtained parameters.Experimental results show that the proposed approach can achieve significant improvement in reducing the peak clustering,and has strong robustness to clutter,especially in complex environment.

Abstract:A novel approach of text images segmentation based on fuzzy logic and spectral clustering is proposed in this paper in order to extract the text from complex backgrounds.Parameters of the function are obtained according to the maximum entropy principle and the original image is fuzzified.Then gray,distance and textural information among pixels are extracted from the fuzzified image to construct the affinity matrix.The original image is segmented using the clustered eigenvector corresponding to the minimum eigenvalue of the matrix.Experimental results show that the proposed method is superior to the usual thresholding methods and can handle the natural scene text image with complex backgrounds.

Abstract:Aimed at the problem that preference elicitation is time-consuming and costly in multi-attribute auctions,a novel iterative multi-attribute auction mechanism for reverse auction settings with one buyer and many sellers is proposed.The auctions support incremental preference elicitation and revelation for the buyer and the sellers.Co-evolutionary computation method is incorporated into the mechanism to support economic learning and strategies for the sellers.The strategy provided by it is in ex-post Nash equilibrium for sellers,assumed that the buyer takes a truthful strategy.Experimental results show that the co-evolutionary computation based iterative multi-attribute auction is a practical and nearly efficient mechanism.

Abstract:In order to reduce the memory consumption of automata algorithms in the field of multi-pattern matching,this paper proposes an efficient space optimization algorithm based on bitmap.It divides all the states in the automata into two groups by their depth in the data structure "trie",and reduces the memory consumption of the deeper group that will be retrieved less.It also makes use of bitmap to improve the time efficiency of the deeper group.Our experiments show that this algorithm can sharply reduce the memory consumption,and when the number of patterns is more than the level of 10 thousand,the space consumption can be decreased by 25%-70%.

Abstract:To improve the precison of collocation extraction,this paper proposes a new method based on Internet data.For the constraint by the corpus scale for traditional collocation extraction approach based on linguistic corpus,we acquire collocations from Web,which contains plenty of information and knowledge.Three classical association measures of co-occurrence frequency,mutual information and χ2-test are used to automatically extract the collocation.Based on the experimental results,the benchmarks show that the performance of this new Web-based approach is superior to that of traditional approach in both precision and recall.Thus the data from Internet may be applied in many NLP applications.

Abstract:To optimize the preparation process of non-crystalline maize starch and characterize its structure,the refrigerated planetary ball mill was employed to produce non-crystalline maize starch and the technical conditions of the ball mill were optimized using response surface test.Based on the single-factor test,the mathematical regression model was established through Box-Benhnken center composite design and response surface analysis.Then the optimum technical conditions are achieved as the milling time of 2.35 h,the rotating speed of 482 r/min and the ratio of ball to material of 5.68:1.Under these conditions,the relative crystallinity of non-crystalline maize starch reaches 1.91%.No new functional group is found in the non-crystalline maize starch by the analysis of FT-IR spectrogram.The characteristic absorption band of 1 047 cm-1 characterizing the crystalline structure of non-crystalline starch disappears,and that of 1 018 cm-1 characterizing the amorphous structure of the starch is broadened.13C CP/MAS NMR analysis indicates that the regular double helix structure in native maize starch has been uncoiled to the disordered single helix structure in non-crystalline maize starch.

Abstract:To obtain new natural antioxidant,11 yeast strains isolated from raw milk were screened by determining their capability to scavenge 1,1-diphenyl-2 picrylhydrazl (DPPH) free radical and inhibit linoleic acid peroxidation,including their intact cell and cell-free extracts.It was found that Pichia fermentans BY5 showed excellent antioxidant activity.Then its antioxidant activity under different initial pH and incubation time as well as culture media of wort,YPD and PDA was analyzed.The results revealed that all these conditions significantly affected the antioxidant activity (P < 0.05),and the protein contents showed a remarkable correlation with antioxidant capability (P < 0.01).In addition,the capability of scavenging DPPH of BY5 extraction reached 60% when being cultured with initial pH 6 in wort for 2 d,and the inhibition of linoleic acid peroxidation reached 74% in YPD for 4 d.

Abstract:To study the durability of concrete subjected to multiple damage factors,by adopting high concentration chemical attack solutions,we investigated the strength development of ordinary Portland cement concrete (OPC),high-strength concrete (HSC),high-performance concrete (HPC),steel fiber reinforced high-performance concrete (SFRHPC) and high elasticity module polyethylene fiber reinforced high-performance concrete (HEMPFRHPC) subjected to double damage factors (DDF),which are the combined actions of freezing-thawing cycles and chemical attack,and multiple damage factors (MDF),which are the combined actions of flexural load,freezing-thawing cycles and chemical attack.Results show that when subjected to 1 500 cycles of DDF or 1 600 cycles of MDF,the compressive strengths of all tested concretes are decreased.Further research indicates that there exists a critical stress ratio for flexural load to impair compressive strength of high grade concrete subjected to MDF,which is 40%,40%,20%,and more than 65% for HSC,HPC,PFRHPC and SFRHPC,respectively.It can be concluded that mineral admixture benefits the compressive strength of high grade concrete subjected to bittern MDF,additional steel fiber can even guarantee the continuous increase of flexural strength.

Abstract:This paper presents a general method that is based on spring-mass system (SMS) for deployment analysis of inflatable membrane structures.Firstly,the inflatable deployment of the coil-folded tube was simulated by SMS method.The inflatable deployment experiment on an air track was conducted,and the results agreed well with those of the numerical method.Secondly,the influence of inflation rate on deployment dynamics characters was discussed and the results demonstrated that variations of inflation rate had a great influence on the deployment process.Finally,the deployment processes of toroidal inflatable boom and inflatable membrane were researched.Compared with conventional finite element methods,the SMS based method provides more flexibility for solving deployment analysis of inflatable membrane structures.

Abstract:To ensure successful pumping and excellent crack resistance,special SFRC was prepared through optimizing the matrix,the shape and size of fibers.The pumpability,shrinkage,cracking,direct tensile strength and toughness were considered.According to the vertically pumping results,the prepared SFRC can be continuously pumped up to a concrete tower with the height over 300 m.Test results demonstrate that steel fiber can diminish the dry shrinkage of concrete in later period,and can improve the mechanical behaviors of concrete matrix.Results of cracking test indicate that the crack resistance is increased by 40% approximately due to the addition of steel fiber to concrete beam.It is also found that in the full-scale model test of main tower,the maximum crack width,cracking length and run-through crack number of anchorage zone poured by SFRC are all less than those of anchorage zone poured by contrast concrete.Therefore,the prepared SFRC is suitable for anchorage zone of the concrete tower and can be used in other zones suffering complex forces.

Abstract:In order to investigate the effect of steel fibers and polypropylene fibers on flexural behavior of HPC deep beams,four-point bending tests were conducted on 17 simply supported HPC deep beams with different fiber contents and steel bars.Results show that the first crack load of FRHPC beams (either single type or hybrid) is increased by 10%-40%,the yield load of hybrid FRHPC beams is increased by 50%-150%,and its ultimate flexural capacity is increased by 1-2 times.Thus hybrid fibers can be used to greatly increase the flexural capacity of HPC deep beams,but the failure pattern of hybrid FRHPC beams without steel bar is brittle failure,it means that hybrid fibers can not replace steel bars.The method to calculate the ultimate flexural capacity of hybrid FRHPC deep beams is discussed as well.

Abstract:The immune genetic algorithm (IGA) was introduced into the fast optimization of antenna design.By employing antigen recognition,concentration regulation as well as memory mechanism,and adopting a new hybrid encoding to simplify the description of antenna structure and the operations of crossover and mutation;the fast optimization of antenna structure was realized.;The simulation of ST5 satellite antenna was carried out to verify the proposed method.Results show that the iteration times are reduced evidently in the antenna design,the convergence rate is sped up about 50%-60%.The maximum and minimum average gains for the designed antenna at 8.47 GHz are increased by 119.91% and 258.89%,respectively.Compared with traditional genetic algorithms,IGA overcomes their shortcomings in local search and avoids the problem of immature convergence,which proves the effectiveness of IGA in the antenna design.

Abstract:A new index structure for spatial data,RQOP-tree,is proposed by setting up the order relation between data rectangles to partition the data spaces,aimed at the existing problems in current index structures based on R-tree and quadtree.In this structure,the middle nodes are constructed according to the distribution of spatial data instead of partitioning the data space evenly,therefore the height of the tree is guaranteed as low as possible and a comparatively small overlap between brother nodes can be kept.In the range query algorithm,the check of query window containing a node’s MBR is introduced to speed up the query effectively for a comparatively large query window.The algorithm for constructing the index structure is given,and its time complexity as well as its correctness is presented.The algorithms for node insertion and range query are obtained.The experiment shows that the query speed is increased greatly.

Abstract:Based on the semi-static two compartment model,the bioaccumulation and elimination of zinc by tissues of Styela clava were investigated,the kinetic parameters of accumulation rate constant k 1,elimination rate constant k 2,bioconcentration factor F BC,biological half life B 1/2 and the maximum equilibrium concentration QAmax were obtained by non-linear regression.The results show that zinc can be accumulated by S.clava from aquatic environment.F BC decreases with the increasing metal concentration in water,and when the accumulation achieves balance,QAmax shows positive correlation to metal concentrations in water.Concentrations of zinc in different tissues of S.clava are listed as:gonad > digestive gland > other part > crust.B 1/2of zinc is 11.36-23.98 d in the phase of elimination.Zn can be accumulated in gonad of S.clava largely and the digestive gland can be used to monitor the pollution of zinc in sea water.

Abstract:In order to find the optimal photocatalytic conditions for nano-TiO2,the Fe3+-doped nano TiO2powder was prepared by sol-gel method using butyl titanate as raw material.Its composition was determined by XRD.Its photocatalytic properties were examined by UV-Vis,and the effect of external conditions including light intensity,pH value and surrounding temperature was disscused.Results indicate that in a certain range,the photocatalytic activity is enhanced with the increased light intensity,and the highest photocatalytic activity is achieved when pH =4,while the ambient temperature has little effect on photocatalytic reaction.