Search

In order to reach the requirements of the newest generation of wire bonder, gas bearing positioning stage directly driven by voice coil actuators is designed.In the stage,an air decoupling mechanism is used. And the finite element analysis software ANSYS was used to analyze the static and dynamic characterizes of the stage so that the structure meets the requirement of stiffness,and at the same time,the moving parts are as light as possible. The simulated results show that the maximum deformation of work platform is in the work surface and the deformation is in request scope.,the deformation of decoupling mechanism is in the main driving rod contact, but this has a little influence on the stage.

A series of near-rapid solidification experiments were performed to investigate the structure evolution in Fe-(6, 11, 13, 17, 21) wt.% Mn and Fe-11wt.%Mn-(0.1, 0.5,1.4) wt.% C strips. The α’-martensite of body-centered cubic structures were observed in all Fe-Mn alloy strips. The ε-martensite phase appeared when the manganese content was up to 13wt.% and its amount gradually increased with the increasing of manganese content. The austenitic phase began to appear in Fe-21wt.%Mnstrip. As for the solidified structure analysis, the Fe-13wt.%Mn strip had a quite large equiaxed grain zone, while other Fe-Mn strips mainly consisted of columnar grains grew from the surfaces. The addition of 0.1wt.%C was helpful for the formation of ε-martensite in Fe-11wt.%Mn strip, but the addition of 0.5 and 1.4wt.%C promoted the transformation of ε-martensite to austenite phase. And addition of 0.5wt.% carbon could increase the area ratio of equiaxed grains formation.

In this paper, frequency domain analysis and application of electrochemical noise of X80 Pipeline Steel in Xinzhou Soil is researched. In the frequency data analysis of electrochemical noise, there are three characteristic parameters. It can be seen from experiments that X80 steel buried in Xinzhou soil with14% moisture content shows that metal corrosion is still not change much. And, it can be inferred that corrosion of X80 pipeline steel in Xinzhou soil with 18% moisture, corrosion is uniform while the morphology is not the uniform , it is the morphology that some pitting are connecting into the film. In Xinzhou soil with 22% moisture, potential PSD figure is different after corrosion happened for one day and three days. Thus, the corrosion type can be determined by high-frequency slope of the linear segment of potential PSD figure.

For different technical reasons, cutouts such as holes in thin-walled structures are inevitable and are of significant technical relevance. Unfortunately open holes usually lead to an undesired stress concentration at the hole vicinity and a reduced load carrying ability of the structure. Therefore the mechanical properties of fiber-reinforced composite laminates with open holes are studied in the paper. The influences of the size and shape of the holes are investigated. A progressive failure finite element model is developed with software ABAQUS. Different failure modes of the composite laminates with various holes are simulated under the Hashin failure criterion. The computational results show that the hole/s have a significant effects on composite laminates properties, and the conclusion can be provided as a good reference for the design of the composite laminates with hole/s.

The supervision monitoring program of radiation environment around nuclear power plants is an important basis for the environmental radiation monitoring work. Key elements such as source, exposure pathway and representative person are discussed in the design of the supervision monitoring program, and technical details about the review of monitoring, evaluating and quality assurance are also given in this article. For the supervision monitoring work of radiation environment around nuclear power plants, it can provide some guidance about the review of the supervision monitoring program for nuclear safety regulators, and provide some reference about the design and revision of the supervision monitoring program for nuclear safety monitoring departments.

The pressed powder sample was determined by Epsilon 5 high-energy polarized energy dispersive X-ray fluorescence (EDXRF) spectrometer. The correlation coefficient of the standard curve method is 0.991 0. The precision is 2.98% and the relative deviation of the measurement standard samples is up to 6.40%, which showed that the precision and accuracy of the method were also good. Simultaneous measurement of seven soil samples with this method and γ-spectrometer were carried, the results of two analytical methods was compared using a paired t-test by SPSS program, which showed that there was no significant difference in the two sets of data. The results predicated that EDXRF could be a potential simple method for analyzing 40K in soil samples.

In order to develop small-scale natural gas liquefaction equipment, a small expansion natural gas liquefaction process was designed, which was based on the technical parameters of the single screw compressor and expander developed by Beijing University of Technology. The effect of the key parameters on the natural gas liquefaction rate and specific power consumption was simulated and optimized. The results showed that the liquefaction rate of the process can reach 100% and the specific power consumption was relatively low under the optimal operation conditions. These research results can provide theoretical basis for the design of small-scale natural gas liquefaction equipment.

To study influence of LED light source lifetime on electricity consumption, optimization of BP neural network is adopted to establish analysis model of energy consumption for neural network, regarding environmental illumination, LED working face illumination, attenuation rates of LED lifetime as input parameters and PWM as output parameters. Under future lifetime of LED, energy consumption is predicted through the model. Results show BP neural network based on genetic algorithm can calculate energy consumption of LED light source quickly and accuracy of prediction is high. The method can be well used to predict energy consumption of short-time LED.

MCF-7 breast cancer cell line was first developed by Dr. Herbert Soule from a pleural effusion taken from a patient with metastatic breast cancer. This estrogen-responsive and estrogen receptor containing cell line can also express androgen, progesterone, glucocorticoid and retinoid receptors. It has been extensively used in identifying environmental estrogens and exploring the toxicity mechanisms, as well as the pathologic study and the disease treatment. This mini review article will focus on the development and application of MCF-7 cells in endocrine-disrupting area, especially in study of environmental estrogens.

Tangentbug algorithm requires the robot to select the moving point by the distance of the intersection of the partial scanned tangent picture, thus the algorithm is simple and of high real-time characteristics. Robot obstacle avoidance game is a regular event of FIRA ROBO WORLD CUP (Robot World Cup Soccer League). This article applies the Tangentbug algorithm into the obstacle avoidance by NAO robot, gets partial map information by NAO robot vision sensor, and analyzes and processes image information. By a few steps such as visual processing, corner extraction, distance conversion, direction calculation, and angle calculation, we get the motion paths of robot. The experimental results show that, Tangentbug can produce a shorter path in a short period of time.

In order to improve the prediction accuracy of the grinding surface roughness, this paper presents a prediction algorithm based on Least Squares Support Vector Machine with Particle Swarm Optimization (PSO-LS SVM). Chose the radial basis function as the kernel function of this new algorithm in where the regularization parameter and kernel function parameter of LS SVM were optimized by PSO, then the grinding surface roughness prediction model was established with the parameters optimized before. Through experimental analysis, it can be realized that compared to the conventional prediction methods, the prediction results of the proposed algorithm are closer to the actual roughness and the relative errors are smaller. As a result, the proposed algorithm is more acceptable.

A novel doping scheme for graphene was recently realized experimentally by creating different vacancy complexes doped with a transition metal (TM) atom [nanoLett. 12, 141 (2012)]. This provides a new reliable way to modifying the electronic structure and transport property of graphene. Here, we show, by performing first-principles calculations, that the defect complex of TM@V4(a TM atom doped tetra-vacancy) in zigzag graphene nanoribbons (ZGNRs) can lead to a 100% spin-polarized electron transport in a wide energy range around the Fermi energy. Analyses show that this is due to the particular atomic structure of the TM@V4complex regardless of the species of the TM atom.

The method of postulate of relatively intact model in the disturbed concept model is reached. Because it is more difficult to assume relatively intact curve by observed experimental data, a method which could automatically calculate the stress strain relation curve of relative intact by triaxial compression test data is raised, so that the determination of material parameters becomes easier, and the improved method is verified by numerical calculation. The results show that this method can effectively determine the stress strain relation curve of relative intact.

Because the higher education has entered popularization stage, the contradiction between the unlimited demand for higher education resources of colleges and universities and the limited supply of resources becomes more and more prominent. Similarly, college sports resources is also limited. How to optimize the sports curriculum according to the students quality is a subject worthy of study. This paper proposes to study the students sport quality such as vital capacity, grip strength, enduranceuse using Pearson correlation and Kmeans clustering algorithm. It can provide guidance for sports education curriculum and teaching content. And we use 2013 freshmen sports test data of an university as example, the experiment proves that the present algorithm can effectively guide for curriculum set.

The increase in the number of private cars as well as non-standard parked behavior has brought great pressure to campus traffic. In order to control this non-standard parked behavior, orderly and reasonable guide and regulate owners to develop good parking habits, we design a vehicle parking violation notification system. A system is designed in the article to record illegal parking information of vehicles. A working principle of this system is that a wireless MMS image terminal captures image information of illegal vehicles, and real-time transmits the captured image information to the Data Center Computer in Security Department of the school through the GPRS network, so as to achieve illegal vehicle information is timely recorded and notified. Meanwhile, outside campus of illegal vehicles will be warned or limited its re-enter the campus. After a year of work and testing, the entire system is stable, and the image information transmission failure rate is very low. Illegal parking behavior on campus has been significantly curbed, and traffic order has been significantly improved.

This article presents the design ideas of patrol system based on real-time image acquisition in patrol points. In this system, the image acquisition terminals are mounted on many patrol points, which are set in a predetermined patrol line. When patrol officers arrived at a patrol point, the image acquisition terminal mounted on the patrol point will capture a live image via a GPRS MMS module ,and then the image acquisition terminal sends this image to the central control unit in a form of MMS. The central control unit receives the sent MMS message, and separate out the image information from the received message, and then saves it to a database. According to the actual test results of this patrol system, it can not only meet the design requirements, but also the whole system has a high stability and reliability.

Through artificial seawater simulation test this paper analyzed erosion mechanism of concrete corroded by the ions in seawater. High performance marine concrete was successful developed because of mineral admixture and corrosion-resistance additive double adding. The paper researched the durability of concrete containing freeze-thaw cycles and chloride ions diffusion. Modern testing technologies were used such as scanning electron microscopy and differential thermal analysis in the experiment. Research founded that the amount of unstable or metastable matter reduced such as calcium hydroxide and high alkaline calcium aluminates in the marine concrete. There were more compact hydration products created which made the structure stabler and denser. Those were the reasons that the marine concrete had excellent performances in terms of erosion-resistance and durability.

To improve the grinding of cassiteritepolymetallic sulfide ores, this paper studied the effect of six kinds of grinding aids. We found that these six kinds of grinding aids can change the grinding effect, but only PAM can make the eligible size fraction increase and decrease the lack-grinding size fraction and the overgrinding size fraction, and reaches the effect of the original study expectation.

For the middlings (containing siderite) separated from Dong Anshan carbonaceous iron ore which was dressed by a two-step flotation process, using roasting-magnetic and regrinding-magnetic separation, the iron concentrate with iron grade and iron recovery of 60.31%, 87.49% was obtained. Mechanism of reduction-roasting was studied by means of XRD in the end.

The temperature field and stress field were simulated using the finite element software (ABAQUS) for Q345c continuous casting slab during cooling process. The hot ductility curve, high temperature tensile strength curve, and the surface stress value were obtained according to thermal simulation experiments. The results show that the temperature of brittleness zone is at 600-850°C, and the value of surface stress is larger than the high temperature tensile strength in the slab cooling process. The heat insulation device should be installed between the flame cutting machine and the heating furnace to avoid hot crack defects caused by excessive thermal stress on the surface in the process of hot slab delivery.

The monodispersion situation of Multi-walled carbon nanotube dispersion is vital for fabricating high quality MWCNT buckypapers with vacuum filtration method. In this paper, the MWCNT buckypapers were fabricated by surfactants Triton-X100, sonication, centrifugation, vacuum filtration, rinsing and annealing processes. Transmission electron microscopy (TEM) and Zeta potential results show the maximum achievable separation has been reached. The properties of MWCNTs buckypaper can be characterized by Scanning electron microscopy (SEM), a four-point probe, N2 adsorption isotherm, TGA-DSC methods. The results showed that the buckypaper exhibits a low surface and volume density, a high porosity and electric conductivity. The pore diameter is up to 22.02nm, no substantial mass loss below 600°C in air.

The external locking device of a railroad switch is an important installation to lock switch rails and stock rails or wing rails by a switch machine. A locking bar can link with the actuator pole of the switch machine to finish switch and act in concert with the locking hook to lock the system. It is required adequate mechanical properties such as yield and fatigue strength. The text analyzes macro-feature of the fracture of a locking bar with failure and gets the conclusion that the locking bar fatigue fractured under alternating load. Metallographic structure and hardness of the material are also examined and found that quenching tends to be overheated with its poor hardenability. The solution is to improve the heat treatment method and increase the fatigue strength.

Through a comparative analysis, this paper attempts to summarize the hourly variations of the total energy consumptions and itemized energy consumptions in a culture and education comprehensive building in summer, winter, and the transitional season. The results show a great difference in energy consumptions in the same building in different seasons. Energy consumption is highest in winter. There is a minor difference in energy consumptions between a typical day in summer vacation and a normal work day in summer. The lowest energy consumption is in winter vacation, but a typical day in winter vacation would still consume about half of the energy consumed on a normal working day in winter. Keywords: Comprehensive building; analysis of energy consumption; itemized energy consumption

Facing with increasingly serious problems such as energy depletion, global warming, world economic depression, and even political fluctuation, energy security gradually became a global concerned issue. Correspondingly, many studies on energy security have been conducted. Focusing on energy security assessment, a review is presented in this paper, covering the definition of energy security, assessment indicators of energy security, and assessment cases at different scales. It is concluded that a systematic model is required to simulate the energy system in a holistic way and to establish more objective and comprehensive indicators of energy security. The review is hopeful to shed light on the development of energy security study in the future.

To solve the instability of the single pair bars RCCR mechanism, the analysis of kinetic characteristics and force rules of three pairs of dowel bars Equal-offset space RCCR mechanism was done. And then the simulation of the theoretical results was verified by SolidWorks simulation software. Finally ,the important conclusions are obtained.

Monodispersion of multi-walled carbon nanotubes with assistance of surfactants has become a usual procedure. A parametric analysis of sonication was performed in order to optimize the preparation procedure of MWCNTs monodispersion solution. MWCNTs solutions were characterized with results of UV-VIS absorbance and FT-IR spectra in order to find the optimal sonication time and power. Perfect sonication time obtained at the higher absorption peak 2.699 in 400nm is 42min, which can be define as sonication cycle. MWCNTs can achieve its optimum dispersion situation, when onication power is 270w, In this case, zeta potential can get as high as-45.2mv. Film achieved under combination of two kinds of optimization parameters is more smoothy and integrated.

A general lattice Boltzmann Method (LBM) to simulate filling process of high pressure die casting (HPDC) is investigated. Boundary conditions are studied and the free surface model is established by combine the LBM with VOF method. The final model was substantiated by simulating filling process in HPDC in three dimensions. The simulated results from LBM and finite difference method (FDM) were compared with the experiments. The results show the former is in a better agreement with experiments. It demonstrates the efficiency and precision of this LBM model in describing flow pattern in filling process.

BiFeO3coated ferromagnetic Fe nanocapsules is synthesized by arc-discharging method. Typical HRTEM images show that the nanocapsules form in a core-shell structure. X-ray photoelectron spectrum (XPS) and X-ray diffraction (XRD) reveal that the core is ferromagnetic Fe, while the shell is BiFeO3/Bi2Fe4O9.The reflection loss R of less than -10 dB was obtained for the whole frequency within the 2-18GHz range by choosing an appropriate layer thickness between 1.0mm and 7.0mm. An optimal reflection loss of -21.5 dB was reached at 10.6 GHz with an absorber thickness of 2.0mm. It is worth noticing that the BiFeO3coated Fe nanocapsules have two absorption peaks below -10 dB at each thickness layer ranging from 4.0nm to 7.0nm, which means the composites nanocapsules absorber simultaneously are able to absorb microwaves in different band of several GHz.

In recent years, with the large-scale grid connection of wind power, wind power as an important factor to load forecasting should not be overlooked; A least squares-support vector machine (LSSVM) has been improved for the region including wind power, based on the influence from the load caused by the changes of wind and the characteristics between load and wind power. The method uses the models of least squares-support vector machine to classify and build different models , and gets the integration of each model for equivalent load forecasting, which provides the reference for the region including wind power.

Semiconductor manufacturing is a capital-intensive and high-tech industry. In order to reduce installation cost and increase production flexibility, twin-fab concept has been established over the past decade, which means two neighboring fabs can be connected to each other by automatic transportation system (AMHS). The capacity backup can be performed between twin fabs to increase whole performance. In this work, a performance evaluation model is proposed to estimate the whole production performance of twin fabs under backup policy. Two situations of capacity shortage are discussed, temporary and permanent capacity shortage. The queuing theory and Little’s Law are used in this model. Besides, the expected value is applied for the estimation of the transportation time under backup activities. Based on the evaluation model, managers can obtain an appropriate estimation of performance under capacity backup in twin-fab environment, which will help to get the reliable information for decision making.

In this current paper, the influence of system efficiency and system parameters for simple compressed energy storage system were studied. EES software is used to simulate the pressure of system and efficiency of compressors, expanders, and pump for getting the optimal parameters of system. The results show that: for the simple system, when the expander inlet pressure is 6000kPa and compressor outlet pressure is 4000kPa, the system efficiency could get the maximum, and it is 76.2%. It is a better way for improving the efficiency of compressor and expander than the pump for system performance.

A general kinetics equation was deduced for bifunctional polyesterification taken account of the changes of density during the reaction process. Kinetics parameters were given by using mol•L-1and mol•kg-1as the unit, respectively. The results show that the kinetic parameters expressed with mol•L-1are greater than those with mol•kg-1in the system of Neopentyi glycol/Maleic anhydride, and particularly the relative errors between them are increased along with the rise of temperatures.

Expected to the non-grid characteristics and pure Lagrangian properties of SPH, the simulation of casting’s filling process would be simpler and precise. In this study, the implementations of SPH method are studied for liquid metal flow and heat transfer during the filling process. The temperature based thermophysical parameters are fitted and add into flow-heat coupling program. The temperature recovery method is included to consider the effect of latent heat. The validation of one-directional heat transfer problem shows that the SPH results have good agreement with the analytical results. The maximum relative error is less than 3%. Finally a circular part is calculated and proved that the SPH model used here works well and has enough precision to capture the behavior of the filling process.

A new organic clay mineral(O-MMT) was synthesized by using montmorillonite(Na-MMT) and bis-type quaternary ammonium compound, 1,5-(pentamethylene) bis (N,N`-diethyl dodecyl acetate ammonium bromide) [PDA] and its CEC, hydrophobicity and algaecide activities were investigated. Results showed that contact angle of Na-MMT and O-MMT are 45.3° and 138.0°, and their CEC are 1.02 and 1.43 mmol•g-1, respectively. O-MMT had 98.5% average algal survival rate against Microcytis, Anabaena, Chlorella and Chlamydomonas at the optimal algaecide conditions, 48h treatment time and 1.0 g•L-1 dosage, which is far higher than 48% of Na-MMT.

According to the situation that the N and P indexes in the MSBR process of municipal wastewater treatment plant can’t meet the I-A wastewater discharge standards of China, the optimized operation parameters were put forward, including improving the sludge within the reflux ratio, opening the return ratio, increasing SBR hypoxia anoxic mixing time, controlling of dissolved oxygen in the aerobic tank,and so on. Through industrial experimentation, the effects of enhanced bio-denitrification were also discussed. The experiment results show that the wastewater treatment plant with 7-tank process of MSBR will meet the I-A wastewater discharge standards of China of the N concentration in effluent through enhanced bio-denitrificaion, but it have bad impact on the TP removal, then through chemical dephosphorization in advanced treatment the effluent water quality will satisfy the I-A wastewater discharge standards of China entirely.

Convection heat transfer in a plate channel periodically fitted with sintered copper porous ribs attached to a copper plate was numerically studied. The local thermal equilibrium model was adopted in the energy equation to evaluate the temperature of fluid and solid. The effect of porosity, Reynolds number and heat flux applied to the copper plate on the heat transfer characteristic of the porous media was investigated respectively. The numerical results show that the heat transfer can be enhanced by increasing Reynolds number, decreasing the porosity and the heat transfer enhancement of the porous media took effect significantly when subjected to high heat flux. Detailed development of the porous media temperature field and the Nusselt number of the wall as a function of Reynolds number for different porosity and heat flux were also presented.

Power battery thermal management system (BTMS) is very important for the safe operation of electric vehicles (EVs). The cooling effect of air cooling, phase change material(PCM)cooling and liquid cooling applyed to BTMS are compared. The experiment results show that, in comparison with air cooling, PCM cooling and liquid cooling methods can reduce the battery temperature rise effectively; in comparison with PCM cooling, liquid cooling has a better effect in the aspect of controlling the battery temperature rise.

Several core parameters in supercritical thermal power plant were briefly outlined, which had the significance in safe and economic operation. The influence and damage of Cl-, SO42- in steam and water system were discussed, and the mathematical relationship between the cation conductivity and the concentration of Cl-, SO42- was described in room temperature. Meanwhile, the iron transport and deposition in steam and water system was analyzed, according to iron oxide solubility at different temperature and pressure.

Two sets of comparative experiments to evaluate the performance difference between the untrained and the trained subjects are presented. In the experiments orientation information were transmitted into the given tactor vibrating of a wearable vibrotactile display waist belt consisting of 12 tactors. The results show that subjects could receive vibrotactile information better and faster after training.

The mechanism of sodium hypochlorite reducing organic matter in boiler makeup water is disscussed. To remove organic matter, sodium hypochlorite sterilizes the boiler makeup water through its strong oxidbillity and oxidates small unsaturated molecules directly and improves the surface properties of macromolecule organic matter. Besides, the organic content in boiler makeup water can be reduced through the synergistic effect that happens between NaClO and Fe2+ when the water contains Fe2+

For theoretical modeling of water flow and heat transfer processes in fractured rocks, one of the most commonly employed assumptions is that instantaneous local thermodynamic equilibrium exists between the water, the fills in the fractures, and the surfaces of the neighboring rock matrix blocks. An analysis of the effects of such assumption is conducted through semi-analytical calculations of heat transfer in a single fracture impermeable rock. It is observed that, for the heat exchange between water and fill, the ratio of the convective coefficient and the grain size acts as the major influencing factor to the validity of the instantaneous local thermal equilibrium between water and fill, that the discrepancies caused by using the thermal equilibrium for heat exchange between rock matrix and water can be significant at locations close to the heat source and at early times of the process, but reduce rather quickly to negligible levels as the distance to the heat source and the time increase, and that the influence of the thermal equilibrium assumption also becomes less significant if the water velocity is small, if the heat capacity and conductivity of rock matrix is small and the convection coefficient is large.

Cu-1.37Cr alloy powders were prepared by gas atomization process, and the cooling rates of alloy powders were calculated through the convection heat transfer principle. The morphology, distribution of alloy elements and microstructure of Cu-1.37Cr alloy powders were characterized by X-ray diffractometer and Scanning Electron Microscope (SEM).The results show that the cooling rate increases from 9.75×103 to 1.08×105 K/s as grain size decreases from 150 to 45µm. The morphology of alloy powders are spherical or similar spherical shape along with smooth surfaces. The grains have uniform size, and Cr particles are uniformly distributed in Cu matrix. With decrease of particle sizes, the diffraction angle shifts into small angle, suggesting that the larger solubility of Cr in Cu phase.

Today CFD is an important tool for engineers in the automotive industry. To simulate and optimize the fluid flow and heat transfer in the engine, the research is carried out. The geometric models of a gasoline engine and the cooling water jacket are simplified by Pro/E software firstly. Then solid - liquid coupled heat transfer analysis is done by using CFD software FLUENT. Temperature field distributions in the engine body and the cooling water jacket are obtained. An engine temperature test bench is set up, on which temperature values of key points are measured. The analysis on the errors between the experimental data and the calculation results shows that the temperature distributions in the engine are reasonable and the cooling performance of the water jacket meets the design requirements. The deviations between the experimental data and calculated values on the measuring points are not big, so the calculation method has high accuracy. The data obtained in this experiment can be used as the basis in the following study.

A visible-light-active N-TiO2photocatalyst was prepared by a simple method: TiN nanoparticles were calcined in the O2/N2atmosphere. The prepared N-TiO2shows high photocatalytic activity for the degradation of methyl orange in water under visible light irradiation. The photodegradation results indicate that the prepared photocatalysts have the best photocatalytic activity when TiN was calcined at 650 °C for 15 min in the O2/N2atmosphere with 1:15 (volume) of O2/N2.

Low density printing paper was widely used in printing best-seller at present. Besides of high bulk, good stiffness, soft color, it also had some advantages, such as reducing user’s load, protecting eyes, extending the storage time etc. Quality index of domestic low density printing paper was lower than foreign index. The gap mainly expressed on tensile index specially. This study used Aspen BECMP as main pulp, as a result of its higher strength, lower cost and other advantages comparing with PRC-APMP. Here we discussed three pulps ratio to make low density printing paper. The results of experiment indicated that using Aspen BECMP was able to make low density printing paper by adding certain amount chemistry pulp. Moreover, the best bulk value can up to 2.45cm3/g, and the tensile index was 36.08Nm/g.

A series of catalysis hydrolytic depolymerization of PET catalyzed by zinc acetate, zinc sulfate, stannous oxide respectively under microwave irradiation at different temperature with time was studied, in which the microwave power was 260W, the ratio of water to PET was 10:1 and the dosage of the catalysts was 0.5% of PET. The relative number average molecular weight of the undepolymerized PET was determined by end-group method. The results show that the molecular weight of the undepolymerized PET decreases with the reaction time increasing, and tends to be stable at the end of the depolymerization reaction. Under the same time, the temperature is higher, the molecular weight is smaller. The molecular weight of the undepolymerized PET reduces most quickly with stannous oxide among the three catalysts.

Fe nanoparticles with shell of Ni-P coating layer were successfully synthesized using Ni electroless plating process. Electromagnetic-wave absorption of Ni-P coated Fe nanoparticles has been investigated. In contrast to earlier reported materials, the absorption amplitude of as-prepared samples is found not largely decrease with increasing absorption-layer thickness. A reflection loss (RL) exceeding -20 dB can be obtained for almost the whole frequencies within the 2-18GHz range by choosing an appropriate layer thickness between 0.9 and 6.0mm. The broadest bandwidth (RLu-bands(12-18GHz), is obtained for 1.1mm layer. At the same time, it is worth noticing that in a thin thickness range 0.91-2.0mm, the reflection loss (RL) exceeding -10 dB in the 6-18GHz range is obtained, which covers half of C-bands (4-8GHz), the whole X-bands (8-12GHz) and Ku–bands (12-18GHz).

The effects of different temperatures on catalytic hydrolysis of polyethylene terephthalate(PET) by solid super acids SO42-/γ-Al2O3as a catalyst under microwave irradiation were studied, and in the meantime, the morphology analysis of the undepolymerized PET under the same temperature was investigated by SEM. The results indicate that the depolymerization rate of PET is seriously influenced by reaction time and temperature. The depolymerization mechanism is changed by the solid super acid SO42-/γ-Al2O3, and the depolymerization rate is higher than that of with no catalyst in the whole process of reaction.

ZnO•SrO composite metal oxides were prepared via solid-state reaction and characterized by XRD. The catalysis of ZnO•SrO to PET depolymerization under microwave irradiation was studied, and the undepolymerized PET was analysed by Gel permeation chromatography(GPC). It is found that the catalytic effect of ZnO•SrO was optimum when the ratio of catalyst was 0.5%, and the rate of hydrolytic depolymerization of PET reached 93.13%. The degree of chain scission of PET depolymerization catalyzed by ZnO•SrO is deep to some extent under microwave irradiation.

Different sulfates were used as the catalysts of polyethylene terephthalate (PET) depolymerization under microwave of 250 watts, in which ZnSO4presented the best catalysis in this reaction, and the depolymerization degree (DPD) of PET was reached to 90 %. It was found that the depolymerization was occurred simultaneously on the surface and the internal parts of PET chips by the observation of scanning electron microscope (SEM) images. In addition, DPD increased with the improvement of the polarization forces of these sulfates.