SUBCRITICAL ASYMPTOTIC BEHAVIOR IN THE MODIFIED LUSHNIKOV PROCESS OF POLYMERIZATION

We consider a modified Lnshnikov process as a model of a chemical polymer ization anf study the asymptotic behavior (in the thermodynamic limit;as N →∞)of a particular probability distribution on the set of N-dimensional vectors,tile kth component of which is the number of k-mers.The study study establisles the existence of three stages (subcritical,near-critical and supercritical stages)of polymerization,dependenting upon the ratio of association and dissociation rates of f polymers.The present paper concentrates on the analysis of tile subcritical stage.In the sibcritical.stages we show that tile size of the largest length of polymers of stize N is of the order.log N as N →+∞.

Flow Stress Behavior and Processing Map of Al-Cu-Mg-Ag Alloy during Hot Compression

The hot deformation behavior of Al-Cu-Mg-Ag was studied by isothermal hot compression tests in the temperature range of 573-773 K and strain rate range of 0.001-1 s^-1 on a Gleeble 1500 D thermal mechanical simulator. The results show the flow stress of Al-Cu-Mg-Ag alloy increases with strain rate and decreases after a peak value, indicating dynamic recovery and recrystallization. A hyperbolic sine relationship is found to correlate well the flow stress with the strain rate and temperature, the flow stress equation is estimated to illustrate the relation of strain rate and stress and temperature during high temperature deformation process. The processing maps exhibit two domains as optimum fields for hot deformation at different strains, including the high strain rate domain in 623-773 K and the low strain rate domain in 573-673 K.

Properties and corrosion behavior of Al based nanocomposite foams produced by the sintering-dissolution process

The properties orAl based nanocomposite metal foams and their corrosion behaviors were investigated in this study. For this, the composite metal foams with different relative densities （porosity） reinforced with alumina nanoparticles were prepared using a powder me- tallurgy-based sintering-dissolution process （SDP） and NaC1 particles were used as space holders. Then, the effect of nanoparticle rein- forcement and different amounts of NaC1 space holders （corresponding porosity） on the microstructure, morphology, density, hardness, and electrochemical specifications of the samples were investigated. It was found that as the relative density increased from 60% to 70%, the wall thickness increased from about 200 to 300 pro, which led to a decrease in pore size. Also, the addition of nanoparticle reinforcement and the increased relative density result in increasing metal foam hardness. Moreover, electrochemical test results indicated that increasing the A1203 content reduced the corrosion rate, but increasing the porosity enhanced it.

S^(2-) behaviors analysis in leaching SrS and precipitating high purity SrCO_3 by reduction-decomposition process

A new preparation method （reduction-decomposition process） for high purity SrCO3 was investigated, which mainly includes four processes: reduction, leaching, purification and precipitation. The affecting factors about S2- behaviors in leaching process and the effects of variables on purity and particle sizes distribution of SrCO3 were analyzed theoretically and practically. It is concluded that with the increase of temperature or decrease of pH value in leaching process, the strontium recovery increases, but SrS decomposes and hydrogen sulphide （H2S） gas discharges. The purity of SrCO3 is dependent on dissolution-recrystallization times, for example, the purity of （SrCO3） is as high as 99.97% when it is recrystallized three times. Besides, the solution concentration of Sr（OH）2 and flow rate of CO2 have important effects on particle size distribution of SrCO3 particles, especially, the particle sizes of （SrCO3） meanly distribute in 0.11.0 μm when the flow rate of CO2 is about 2 000 mL/min and other parameters are invariable.

Rheological Behaviors and Processing Windows of Low Viscosity Epoxy Resin for VIMP

The chemorheological behaviors of a low viscosity epoxy resin system （Huntsman 1564/3486） for vacuum infusion moulding process （VIMP） were studied with viscosity experiments.The dual-Arrhenius rheological model and the engineering viscosity model were established and compared with the experimental data.The result showed that the viscosity in the earlier stage calculated by dual-Arrhenius model were smaller than the experimental data,while the data calculated by the engineering model were larger.Combining the two models together can predict the rheological behaviors of the resin system in a more credible manner.The processing windows of the resin system for VIMP were determined based on the two models.The optimum processing temperature is 30-45 ℃.

THE NEAR-CRITICAL AND SUPER-CRITICAL ASYMPTOTIC BEHAVIOR IN THE THERMODYNAMIC LIMIT OF REVERSIBLE RANDOM POLYMERIZATION PROCESSES

In this paper, the near-critical and super-critical asymptotic behavior of a reversible Markov process as a chemical model for polymerization was studied. The results of the present paper, together with an analysis of the sub-critical stage, establish the existence of three distinct stages (sub-critical, near-critical and super-critical stages) of polymerization (in the thermodynamic limit as N --> +infinity,),depending on the value of strength of the fragmentation reaction. These three stages correspond to the size of the largest length of polymers of size N to be itself of order log N, Nm/m+1 (m greater than or equal to 2, m not equal 4n, n greater than or equal to 1) and N, respectively.

Effect of melting temperature on microstructural evolutions, behavior and corrosion morphology of Hadfield austenitic manganese steel in the casting process

In this study, the effect of melting temperature on the microstructural evolutions, behavior, and corrosion morphology of Hadfield steel in the casting process is investigated. The mold was prepared by the sodium silicate/CO_2 method, using a blind riser, and then the desired molten steel was obtained using a coreless induction furnace. The casting was performed at melting temperatures of 1350, 1400, 1450, and 1500°C, and the cast blocks were immediately quenched in water. Optical microscopy was used to analyze the microstructure, and scanning electron microscopy(SEM) and X-ray diffractrometry(XRD) were used to analyze the corrosion morphology and phase formation in the microstructure, respectively. The corrosion behavior of the samples was analyzed using a potentiodynamic polarization test and electrochemical impedance spectroscopy(EIS) in 3.5 wt% NaCl. The optical microscopy observations and XRD patterns show that the increase in melting temperature led to a decrease of carbides and an increase in the austenite grain size in the Hadfield steel microstructure. The corrosion tests results show that with increasing melting temperature in the casting process, Hadfield steel shows a higher corrosion resistance. The SEM images of the corrosion morphologies show that the reduction of melting temperature in the Hadfield steel casting process induced micro-galvanic corrosion conditions.

Effect of laser shock processing on residual stress and fatigue behavior of 6061-T651 aluminum alloy

Laser shock processing is a very new technique and an emerging modern process that generates compressive stresses much deeper into the surfaces of metals or alloys. A brief parametric study of the effect of laser parameters on fatigue behavior and residual stress state generated in 6061-T651 alloy specimens was summarized. Residual stress of 6061-T651 alloy was analyzed both before and after laser processing with multishocks. The material remains in compressive residual stress of approximate 1mm in depth which is approximately 10 times deeper than that can be achieved with the conventional technique, and the maximal compressive residual stress at the surface of the sample is about -350MPa. Near the surface, yield strength and hardness are found to be increased by the laser shock. The ratio of fatigue crack initiation life for the laser-shocked to unshocked specimens is found to be 4.9 for specimens. The results clearly show that LSP is an effective surface treatment technique for improving the fatigue performance of aluminum alloys.

Identification of Behavior of Voluntary Traceability and Analysis of Its Determinants: A Case Study of Hog Slaughtering and Processing Firms in Zhejiang Province,China

In recent years, the Chinese government has highlighted the importance of adopting hog safety/quality traceability, and a growing amount of research continues to entice firms to adopt traceability systems. In this study, a survey was conducted on a sample of pig slaughtering and processing firms in Zhejiang, China through personal interviews and emails. The aim of this study was to examine the determinants of firm behavior on the implementation of voluntary traceability systems with more stringent standards and controls than those of the mandatory system in China. The results revealed that motivation based on product quality improvement, capital ability and role perception （business type） had significantly positive relationships with a firm＇s voluntary traceability. Other incentives, such as operation improvement, recall risk reduction, reduced occurrence of safety issues, and technical strength were not found to be supportive in our study. This study provides an opportunity to better understand the determinants of firm behavior on voluntary traceability, particularly in light of the fact that some Chinese firms are facing the threat of criminal action for the use of illegal additives and the abuse of Clenbuterol. Policy recommendations on encouraging the implementation of pork safety voluntary traceability by hog slaughtering and processing firms are also discussed.

Dynamic Behavior of Interest Rates in China

This paper intuitively examines the dynamic behavior of two highly relevant interest rates in China. The first one is the government rate, which is decided and published by the central bank and can be simulated by pure jump process. Estimation of the jump intension is given out. And by different robustness test, it keeps stable. The jump size has met the condition to make interest rate within reasonable bounds and shown some meaning of economic cycle behavior. The second one is the market rate, which is estimated by spline approximation based on the transaction data of government bonds. Several models, including Vasicek model, Vasicek-GARCH （1,1） model, CIR model, and CIR-GARCH（1,1）, are empirically tested and the best performance is done by the Vasicek-GARCH（1,1） model. Furthermore, the estimate bias problem due to the near unit root process is tested and evidenced by both traditional methods and GPH test. Impact of government rate on market rate is finally checked and analyzed.

Deformation behavior and mechanisms of Ti-1023 alloy

The deformation behavior and mechanisms of Ti-1023 alloy were studied in the temperature range of 650-900 ℃ and strain rate range of 0.001-10 s-1 by compression and tensile tests. The results show that in a limited strain rate range of 0.001-0.1 s-1, the kinetic rate equation is obeyed and a linear fit is obtained at all the temperatures. The apparent activation energy is 322 kJ/mol in the α-β region and 160 kJ/mol in the β region, respectively. Power dissipation maps of this alloy developed by using Gleeble test data show three domains in the tested range. Superplasticity, marked by abnormal elongation at 700 ℃, occurs in the temperature range of 650-750 ℃ and at strain rates below about 0.03 s-1. Large grain superplasticity takes place in the temperature range of 750-850 ℃ and strain rates range of 0.001-0.03 s-1. Dynamic recrystallization occurs in the temperature range of 850-900 ℃ and at strain rates below about 1 s-1. The instability maps of this alloy were also developed.

Vaporization behavior of lead from the FeO-CaO-SiO_2-Al_2O_3 slag system

Vaporization behavior （1163-1463 K） of lead in the slag system of FeO-CaO-SiO2-Al2O3 with CaC% was examined. A thermodynamic estimation with the principle of Gibbs free energy minimization showed that the major vapor species from the sample of the FeO-CaO-SiO2-Al2O3 system＋PbO＋CaCl2 were metallic Pb, PbCl, PbCl2, and FeCl2, at the experimental temperature range. The experimental results show that the mole ratio of vaporized Cl in lead chlorides to vaporized Pb, simply expressed as Cl/Pb decreases with increasing temperature. The larger Cl/Pb means a larger ratio of gaseous PbCl2, since metallic Pb and PbCl vapors are formed in a similar reduction atmosphere. The evaporation is initially rapid and becomes steady after holding for 10 min. Gaseous PbCl2 is mainly formed during the heating period, and at the holding stage, it reacts with FeO to produce gaseous FeCl2 With regard to slag composition, FeO content and basicity significantly affect the evaporation of lead. High FeO content and high basicity promotes the formation of metallic Pb and PbCI, whereas, it prohibits PbCl2 evaporation.

Effect of gradient temperature rolling process on promoting crack healing in Q500 heavy plates

To ensure the quality of heavy plate products as determined by ultrasonic inspection, it is necessary to effectively control defects such as cracks and shrinkage cavities in heavy plates. Generally, some defects such as large size cracks exist due to insufficient deformation in the center of traditionally rolled plates. Compared with the traditional rolling process, gradient temperature rolling(GTR) process can effectively increase deformation inside heavy plates. In this study, the effect of GTR on crack healing was analyzed through a comparison experiment with the uniform temperature rolling(UTR). The results show that the GTR process could increase the plastic strain inside the heavy plate and effectively promote the healing process of the preset cracks. The degrees of crack healing at the center and quarter thickness position of the steel plate via GTR were greater than twice those of the plate via UTR. The GTR process can significantly reduce the internal defects of heavy plates and improve the defect detection level of heavy plate products. Also, The GTR process results in the formation of new crystal grains in the crack region, which is crucial to crack healing.

Behavior Consistency Computation for Workflow Nets With Unknown Correspondence

Consistency degree calculation is established on the basis of known correspondence, but in real life, the correspondence is generally unknown, so how to calculate consistency of two models under unknown correspondence has become a problem. For this condition, we should analyze unknown correspondence due to the influence of different correspondences.In this paper we obtain the relations of transitions based on event relations using branching processes, and build a behavioral matrix of relations. Based on the permutation of behavioral matrix, we express different correspondences, and define a new formula to compute the maximal consistency degree of two workflow nets. Additionally, this paper utilizes an example to show these definitions, computation as well as the advantages.

A visualized study of interfacial behavior of air–water two-phase flow in a rectangular Venturi channel

A visualized investigation was carried out on the effect of the diverging angle on the bubble motion and interfacial behavior in a Venturi-type bubble generator.It was found two or three large vortexes formed in the diverging section,resulting in strong reentrant jet flow in the front of the bubbles or slugs rushing out of the throat.The jet flow in return bumps into the ongoing bubbles or slugs,leading to strong interaction between the gas and liquid phases.The diverging angle has significant influence on the reentrant flow process and the performance of the bubble generator as well.Increasing the diverging angle results in the reentrant flow moving further forward to the upstream and intensifies the interaction between the two phases.As a consequence,the breakup or collapse of bubbles becomes more violent,whereby finer bubbles are generated.As such,the reentrant flow strongly links to the performance of the Venturi channel taken as a bubble generator,and that a moderate increase in the diverging angle can improve its performance without additional increase in flow resistance like that by increasing liquid flow rate.

Effects of interfacial discontinuity on the fracture behavior in the superconductor-substrate system

This study concerns a two-dimensional model and the corresponding virtual crack closure technique(VCCT) implemented to solve the general boundary value problems that may explain why interface discontinuity has effects on the fracture behavior in the superconductor-substrate system. The interfacial discontinuity can be classified according to the material properties' continuity and their derivatives' continuity at the interface. For nonhomogeneous superconductor and substrate specimens with various material properties, a VCCT method is developed to calculate their fracture behavior. Furthermore, the effects of applied magnetic field amplitude and nonhomogeneous parameters are extensively and parametrically studied in two activation processes(zero-field cooling and field cooling). The integrative and computational study presented here provide a fundamental mechanistic understanding of the fracture mechanism in the superconductor-substrate system and sheds light on the rational design of interfacial continuity.

Comparative Study of Earing Behavior in Cold Rolled-batch Annealed and Cold Rolled-Continuous Annealed of DoubleReduced (DR) Tinplate Steels

Two double cold reduction-drawn and redrawn(DRD) tinplate steels of the same chemistries that have been processed by continuous and batch annealing line have been researched. The composition of fibers were studied through X-ray diffraction. The results indicate that a strong intensity of {114}<110> was formed in the continuous annealing steel and a strong intensity of {111}<112> was formed in the batch annealing steel; not only that but the γ fiber slowly rotated to the low angel α fiber with the angel being about 30° nearly {112}<110>texture owing to the higher second reduction.

Implementation of Generic AHP Evaluation System and Its Application to Impact Factors of On-Line Consumption Behavior

To implement the computation of AHP （Analytic Hierarchy Process） automatically, make the implementation independence on the platform, and to convenient the service composition and service computation, this study implemented AHP model as a Web service and stored the evaluation information as XML form. This paper introduces the overall demands of AHP evaluation system firstly, and then presents some key technologies to implement AHP evaluation system, including mainly AHP evaluation index architecture based on XML, the class of AHP model, the Web service encapsulation of AHP, the publication and invocation of AHP and the client application. At last, the system is used to analyze the impact factors of online consumption behavior.

Reduction and melting behavior of carbon composite lateritic bauxite pellets

Direct reduction of low-grade lateritic bauxite was studied at high temperature to recover Fe and beneficiate AlzO3 slag. The re- sults show that a metallization rate of 97.9% and a nugget recovery rate of 85.1% can be achieved when the reducing and melting tempera- tures are 1350 and 1480℃, respectively. Moreover, a higher-grade calcium aluminate slag （A1203 = 50.52wt%） can also be obtained, which is mainly composed of ct-A1203, hercynite （FeAI：O4）, and gehlenite （Ca2A12SiO7）. In addition, high-quality iron nuggets have been produced from low-grade lateritic bauxite. The nugget is mainly composed of iron （93.82wt%） and carbon （3.86wt%）, with almost no gangue （slag）.

Asymptotic Behavior for A Class of Non-autonomous Nonclassical Parabolic Equations with Delay on Unbounded Domain

In this article,we investigate the longtime behavior for the following nonautonomous nonclassical parabolic equations on unbounded domain ut−∆ut−∆u+λu=f(x,u(x,t−ρ(t)))+g(x,t).Under some suitable conditions on the delay term f and the non-autonomous forcing term g,we prove the existence of uniform attractors in Banach space CH1(RN)for the multivalued process generated by non-autonomous nonclassical parabolic equations with delays in unbounded domain.