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The jaw crushing loading process is a typical loading process of combined shearing and extrusion. In this paper, by establishing a complete jaw crushing loading process, the sonic test method is used to determine and analyze the particle crushing law to explore acoustic characteristics of particle crushing under the combined action of shear and extrusion. A jaw crushing tester is used to simulate the jaw crushing process of sand aggregate specimens. A rock-soil sound wave detector is used to measure the sound speed, sound amplitude, and sound intensity during the simulated jaw crushing process. It is found that when the jaw angle variation range is 2.6°, the inlet-outlet ratio is 0.332 and the motor speed is 15 r/min, the sound velocity and the sound amplitude curves fluctuate more drastically and the sound intensity is higher. The crushing evaluation of the sand aggregate specimens, which have experienced crushing simulation, shows that when the jaw angle variation range is 3.0°, the inlet-outlet ratio is 0.332 and the motor speed is 33 r/min, higher crushing energy rate and crushing rate are achieved. Through the comparative analysis of each group’s acoustic parameters and crushing evaluations, it is found that both the acoustic parameters and the crushing evaluations reflect the crushing process, but they have similarities and differences. Therefore, to some extent, the acoustic parameters in the crushing process can be regarded as significant indicators for evaluating the crushing effect. This conclusion may be a reference for optimizing working parameters and structural parameters of crushing equipment.

The surface structure and material composition of current collectors have significant effects on the electrochemical performances of lithium-ion batteries (LIBs). In this work, a three-dimensional (3D) porous composite framework is applied as the anode current collector in LIBs. This unique 3D skeleton is composed of conductive carbon fiber/Cu core/shell fibrous structure. With an oxidation treatment upon the copper shell, the porous framework is assembled with CuO microspheres. Using mesocarbon microbead (MCMB) graphite powders as the active material, the cell with this 3D porous composite current collector shows an improved reversible discharge-charge capacity of 415 mAh g–1 at a current rate of 0.1 C after 50 cycles, which is much higher than that of the cell with a flat Cu foil (127 mAh g–1). It is demonstrated that this unique fibrous network of the 3D current collector coupled with the morphological effects of the CuO microspheres greatly improve the cell performance in terms of electrical conductivity, reversible capacity and cycling stability.

In this work, reduced sulfonated graphene (RSG) containing free amine groups was prepared and modified by 3-aminopropyltriethoxysilane (APTES) and reduction by diethanolamine (DEA). In addition, waterborne polyurethane (WPU) composite coatings were prepared by adding RSG as an anticorrosive filler to WPU. From the results of Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy (SEM), it can be found that sulfonated graphene was modified with APTES and successfully reduced by DEA. The SEM images illustrated that RSG was uniformly doped in the WPU. With increasing RSG content, the hydrophobicity of the RSG/WPU films increased due to the strong covalent interaction between RSG and WPU. Finally, the corrosion resistance of the coating was characterized by polarization curves and salt spray tests.

A conductive layer, made of multi-walled carbon nanotubes (MWCNTs), with micro-cracks and a micro/nano porous structure was fabricated between the active material layer (AML) and the current collector in this study. The coating thickness of MWCNTs-based conductive layer (MCL) varies in the range of 25-100 μm. The electrochemical tests of half-cells demonstrate that both the mesocarbon-microbeads (MCMB) anode and the LiCoO2 cathode with a micro-cracked MCL show higher capacity, lower impedance and less capacity fading. These improvements are closely due to the enhancement of adhesion strength, and also the outstanding buffer effect of the micro-cracked MCL. With the change of the coating thickness, the size and amount of the micro-cracks on the MCL varies accordingly to accommodate the active material with different particle sizes. The electrodes including a micro-cracked MCL with a coating thickness of 50 and 75 μm are more suitable for MCMB and LiCoO2 with a particle size of 10-20 μm.

The reduced graphene oxide‑zinc‑aluminum layered double hydroxides (rGO-ZnAl-LDH) micro-nano fillers were prepared via a one-step process, then modified by 3-aminopropyl triethoxysilane and incorporated into a waterborne epoxy (EP) matrix to produce M-rGO-ZnAl-LDH/EP composite coating. The effects of the M-rGO-ZnAl-LDH hybrid on the corrosion resistance of the coating were studied by adjusting the ratio of GO: ZnAl-LDH and also the adding amount of M-rGO-ZnAl-LDH hybrid. The anticorrosive nature of the M-rGO-ZnAl-LDH/EP composite coating had been investigated by potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS) and salt spray test. The results indicated that the corrosion resistance of the coating was improved remarkably when the ratio of GO: ZnAl-LDH was 2:1 and the adding amount was 0.5 wt% into EP. The corrosion current density ( i corr ) was only 0.0733 μA/cm 2 and the coating resistance ( R c ) was up to 2.77E4 Ω cm 2 for M-rGO-ZnAl-LDH/EP (2:1–0.5 wt%), while the i corr for pure EP was 0.469 μA/cm 2 and the R c for pure EP was 2.10E3 Ω cm 2 , which suggested that the M-rGO-ZnAl-LDH micro-nano fillers had a higher anticorrosion properties relative to the waterborne epoxy resins.

This study presents a hierarchical MCMB/CuO/Cu anode structure with super-hydrophilic CuO substrate and blind-hole structures (BHSs) for lithium-ion battery (LIB) application. The porous hierarchical CuO clusters with controllable morphology and super hydrophilicity are prepared and combined with the BHSs on the surface of copper plates (CPs). Results indicate that the new anode yields a considerable improvement in reversible capacity and robustness under the condition of rate cycles. Compared with the conventional pattern of MCMB/Cu, the MCMB/CuO/Cu anode with BHSs produces reversible initial discharge and charge capacities of 381.5 and 347 mAh g−1 at a constant current of 0.5 mA. After 30 cycle times, the battery retains 276.7 and 276.6 mAh g−1, which amounts to 5 times as much as that of 0.5 C rate cycles. The energy density of the battery can be also greatly promoted. The larger surface area and porosity of the new anode facilitate formation of contact interface between the active material and current collector (CC). It also helps shorten the diffusion path of Li-ions and alleviate the volume expansion during the insertion and desertion processes of Li-ions.

Developing high-performance electrode structures is of great importance for advanced lithium-ion batteries. This study reports an efficient method to fabricate hierarchical shell/core CuO nanowire/carbon fiber composites via electroless plating and thermal oxidation processes. With this method, a binder-free CuO nanowire/carbon fiber shell/core hierarchical network composite anode for lithium-ion batteries is successfully fabricated. The morphology and chemical composition of the anode are characterized, and the electrochemical performance of the anode is investigated by standard electrochemical tests. Owing to the superior properties of carbon fibers and the morphological advantages of CuO nanowires, this composite anode still retains an excellent reversible capacity of 598.2 mAh g −1 with a capacity retention rate above 86%, even after 50 cycles, which is much higher than the CuO anode without carbon fibers. Compared to the typical CuO/C electrode systems, the novel binder-free anode yields a performance close to that of the typical core/shell electrode systems and a much higher reversible capacity and capacity retention than the similar shell/core patterns as well as the anodes with binders. It is believed that this novel anode will pave the way to the development of binder-free anodes in response to the increasing demands for high-power energy storage.

The surface structure and material composition of current collectors significantly affect the electrochemical performances of lithium-ion batteries. This study forms array-pattern blind holes and creates a layer of copper oxide (CuO) on the surface of thin copper plates using the chemical etching method. This copper plate is made into a CuO/Cu composite current collector with array-pattern porous structures for lithium-ion batteries. Using mesocarbon microbead graphite powders as the anode material, this new composite current collector is assembled into CR2032 coin half-cells for electrochemical tests. Batteries with this porous current collector exhibit high reversible discharge capacities of 383.9 mAh g −1 at 0.5 mA and 374 mAh g −1 even after 0.2C and 0.5C rate cycles, whereas batteries with a complanate current collector deliver only 309.6 mAh g −1 and 296.7 mAh g −1 . It is believed that the array-pattern blind holes coupled with the morphological effects of the oatmeal-like CuO significantly enhance the electrochemical performances of batteries in terms of reversible capacity, cycling stability, electrical conductivity and coulombic efficiency.

With the environmental regulations becoming more stringent and awareness of consumers increasing to protect environment, an urgent problem is to reduce the use of volatile organic compounds (VOCs). Powder coating is a kind of solid powder coating without any solvent. Due to its excellent application performance and environment-friendly, it is widely used in the field of metal coating, especially appliances of offices and home. In recent years, the use of powder coatings has been developed very fast and the requirements of functional powder coatings are also gradually strengthened. According to resin of the film forming, powder coatings can be divided into two types: thermosetting powder coatings and thermoplastic powder coatings. Each kind of powder coatings has its own advantages and disadvantages, and they will be applied in different fields. In order to improve the properties of powder coatings, there are many reports and studies about them. The compositions of powder coatings were extruded, crushed and screened to gain powder of coating. The powder always was stored at room temperature. The powder coatings often operated by two kinds which were electrostatic spraying method and fluidized bed dipping method. After that, the powder was heated to melt and cure. Finally, a smooth bright permanent film on articles was formed to achieve the purpose of decoration and corrosion. The process flow preparation of powder coatings always separated into dry process production and wet process production. The development courses of powder coatings about resins, pigments and fillers are summarized. The future development trends of powder coatings are illustrated.

Bonding material is one weak point in power modules packaging, and can limit the lifetime of power modules. Multiple bonding materials have been manufactured and applied in the power modules such as aluminum wire, copper wire, aluminum ribbon, copper ribbon, Al-clad-Cu wire, direct-bonding-lead. For bonded power modules packging, bonding ability, electrical and thermal conductivity, current carrying capacity, working reliability are the main applying properties of bonding materials. This paper demonstrates the characterization, failure mode & failure mechanism, life-time calculation model of the normal used bonding materials and estimates the developing tendency.

Peeling failure at the interface is one of the main failure modes for CFRP (Carbon Fiber-Reinforced Polymer)-reinforced steel structures. However, there are very few reported studies on the bond-slip relationship at the CFRP-steel interface. A series of simple shear tests were carried out in the present paper. The influence of the fiber fabric&rsquo, s width and thickness, the surface roughness of the steel sheet, and the thickness of the adhesive layer on the bonding performance of the CFRP fabric to steel interface was considered. The interface constitutive model and bonding strength model were further established under multiple factors. The results show that with the decrease of the surface roughness, the interface&rsquo, ultimate peeling load increases gradually, and the failure has a tendency to develop from a glue-steel interface to a glue-CFRP interface. The test pieces that were subjected to sand blasting obtained the peak value of the ultimate peeling load. This indicates that sand blasting can effectively enhance the interface bonding strength. The theoretical values obtained via the interface prediction model are consistent with the experimental values. This proves that the newly developed interface prediction model can effectively predict the local bonding slip and bonding strength of the interface.

Inspired by the structures and functions of sand barriers in the desert region, in article number https://doi.org/10.1002/advs.201800031 Wei Yuan, Meilin Liu, and co‐workers report a 3D composite current collector with checkerboard‐like surface structure for lithium‐ion batteries. Like the windbreak and sand fixation effects of the sand barrier, the checkerboard‐like surface structure helps to effectively alleviate the pulverization of electrode materials and enhance the electrochemical performance of lithium‐ion batteries.

While the architecture, surface morphology, and electrical conductivity of current collectors may significantly affect the performance of electrochemical cells, many challenges still remain in design and cost‐effective fabrication of highly efficient current collectors for a new generation of energy storage and conversion devices. Here the findings in design and fabrication of a 3D checkerboard‐like Cu@CNF composite current collector for lithium‐ion batteries are reported. The surface of the current collector is modified with patterned grooves and amorphous carbon nanofibers, imitating the checkerboard‐like sand barriers in desert regions. Due to a combined effect of the grooves and the carbon nanofibers, a battery based on this current collector retains a reversible capacity of 410.1 mAh g−1 (beyond the theoretical capacity of carbonaceous materials of 372 mAh g−1) with good capacity retention (greater than 84.9% of the initial capacity after 50 cycles), resulting in 66.2% and 42.6% improvement in reversible capacity and capacity retention, respectively, compared to the batteries using traditional Cu current collectors. Based on the excellent electrochemical performance, this composite current collector is believed to be an attractive alternative to the traditional commercially used current collectors for the anode of high‐power energy storage systems.

An external magnetic field applied in arc welding process results in electro-magnetic stirring (EMS) welding. The added longitudinal magnetic field (LMF) provides an effective method to control the arc behavior and affect the resultant welds. However, few studies have addressed arc behaviors in LMF-TIG hybrid welding, i.e., tungsten inert gas arc (TIG) hybrid welding with an external LMF; the LMF direction is the same as or parallel to the symmetric axis of welding arc. In this paper, a three dimensional (3D) multiphysics field model was established to analyze arc behavior in LMF-TIG hybrid welding. This model is formed by fluid dynamics equations coupled with Maxwell equations. The fields of temperature, velocity, and electric current field were obtained from this model through numerical simulation using the finite volume method (FVM). It was found that the arc changes from its free to strong electromagnetic field controlled status in three stages. After the applied electromagnetic field exceeds a critical value, mutation is induced in the arc resulting in an arc behavior completely different from that of the normal free arc. The arc pressure and temperature distributions shift their centers, where the peak pressure and temperature occur, from the tungsten axis. In addition, the arc exhibits negative pressure (i.e., anti-gravity gradient behavior) below the cathode and a tornado-style behavior. The arc plasma flow reverses, a circular area occurs, and a low-temperature zone forms in the center of the arc. The highest flow speed takes place on both sides of the arc symmetry axis. The unique appearance of the negative arc pressure and its formation mechanism are discussed.

A temperature sensor based on topological insulators and tapered fiber is proposed and experimentally investigated. The tapered fiber and topological insulators solution are encapsulated in a capillary tube using UV glue. Within a temperature range of 47–92 centigrade, one resonance dip of tapered fiber exhibits a blue shift of 10nm, which is more than 20 times of ordinary fiber Bragg grating's temperature sensitivity.

The micro pore array with the feature of aspect ratio of more than 50 was fabricated on a 5-inch silicon wafer by means of photo-assisted electrochemical etching technique.After analyzing the factors that determine the morphology of pores,the following experiments were proceeded to study the relation of pore morphology to the etching voltage and electric current.When choosing a current by i-V curve,several different etching voltages were applied respectively and corresponding wafer was fabricated by adjusting experimental parameters according to the Lehmann′s model.It was found that the better pores could be produced under a voltage of 2 V.The results show that photo-assisted electrochemical etching technique can be more adopted to make the large area micro-pore array of high aspect-ratio on silicon wafer with low cost,being compared to the state of the art of micro-manufacturing technology.

Nano-sized B2O3-doped ZnTiO3 particles were successfully synthesized through sol–gel technique. The crystallization temperature of ZnTiO3 from sol–gel process was confirmed at 800 °C by the X-ray diffraction (XRD), thermo gravimetric (TG) and differential scanning calorimetry (DSC) analysis. The B2O3 content, the high molding pressure and the sintering temperature had great influence on microstructure and the dielectric properties of materials. According to scanning electron microscopy (SEM) analysis, when sintering reagent (B2O3) content was 1 wt.%, the grain growth of ZnTiO3 sintered at 900 °C was anisotropic, and the grain became regular disc structure with a diameter of 2 μm and thickness of 0.3 μm, which might be attributed to the selective growth of crystal grain in a preferential direction. As-prepared 1.0 wt.% B2O3-doped ZnTiO3 sintered at 900 °C for 4 h possessed excellent dielectric properties: Q × f = 49,000 GHz, ɛr = 8.87, τf = −32.35 ppm/°C. The nano-sized, uniform grains contributed to the high quality factor. The porous bulk ceramics contributed to the low dielectric constant.

The anisotropy of two successive transitions of the spin-ladder compound LiCu2O2 is studied by the specific heat (C) under magnetic fields with H// c and H// ab (written as Hc and Hab in the following) up to 14 T. The peak of specific heat at 24.5 K in zero field shifts to lower temperature when the field is increased and the magnitude of the peak is suppressed by the field. On the contrary, the peak of 22.5 K shifts to higher temperature, especially at 14 T. Its magnitude increases in the field of Hc, whereas it decreases in the field of Hab. We calculate the entropy change between 21 K and 63 K. The different influence of the spin ordering by fields of different direction is obtained. Our experimental results suggest a mixed state between the long range incommensurate helimagnetic ground state and the higher-T short-range dimer liquid state. The temperature range of mixed state is shrunk with the increasing field. Possible mechanism is discussed.

Different element substitution effects in transition metal oxypnictide Re(O1-xFx)TAs, with Re = La, Ce, Nd, Eu, Gd, Tm, T = Fe, Ni, Ru, are studied. Similar to the La- or Ce-based systems, we find that the pure NdOFeAs shows a strong resistivity anomaly near 145 K, which is ascribed to the spin-density-wave instability. Electron doping by F increases Tc to about 50 K. While in the case of Gd, Tc is reduced below 10 K. The tetragonal ZrCuSiAs-type structure could not be formed for Eu or Tm substitution in our preparing process. For the Ni-based case, although both pure and F-doped LaONiAs are superconducting, no superconductivity is found when La is replaced by Ce in both the cases, instead a ferromagnetic ordering transition is likely to form at low temperature in the undoped sample. We also synthesize LaO1-xFxRuAs and CeO1-xFxRuAs compounds. The metallic behaviour is observed down to 4K.

We have performed low temperature resistivity ?(T) and specific heat C(T) measurements on a superconducting polycrystalline Nb0.75Mg0.25B2 sample. The results indicate that the superconducting transition temperature is ~ 4.6 K. The zero temperature upper critical field determined from the resistivity and specific heat is 3123 Oe. The electronic coefficient of specific heat ?n = 4.51 mJmol?1K2 and the Debye temperature ?D = 419K are obtained by fitting the zero-field specific heat data in the normal state. At low temperatures, the electronic specific heat in the superconducting state follows Ces/?nTc = 2.84exp(-1.21Tc/T). This indicates that the superconducting pairing in Nb0.75Mg0.25B2 has s-wave symmetry.

A fiber ring down with a weak long period grating (WLPG) for temperature and strain sensing is proposed and demonstrated. The sensing devices consist of two matched fiber Bragg gratings, a section of single mode fiber, a WLPG, a pulsed laser source, and a photodiode. The LPG incorporated in fiber ring cavity is used as sensing element, the induced resonance wavelength shift of which will cause an additional loss in the cavity. As a result, the amplitude of applied temperature variation or strain can be obtained by simply measuring the fiber ring down time. The proposed sensing system has advantages of easy configuration and rapid response. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 111–114, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23006

Collapse-type shrinkage is one of highly refractory drying defects in low-medium density plantation-grown eucalypt wood used as solid wood products. Basic density (BD), microfibril angle (MFA), double fibre cell wall thickness (DWT), proportion of ray parenchyma (RP), unit cell wall shrinkage, total shrinkage and residual collapse, which are associated with collapse-type shrinkage characteristics, were investigated by using simple regression method for three species of collapse-susceptibleEucalyptus urophyll,, E. grandis andE. urophylla×E.grandis, planted at Dong-Men Forest Farm in Guangxi autonomous region, China. The results indicated that: unit cell wall shrinkage had a extremely strong positive correlation with BD, moderately strong positive correlation with DWT, and a weakly or moderately negative correlation with RP and MFA; total shrinkage was positively correlated with BD, DWT and RP and negatively related to MFA, but not able to be predicted ideally by any examined factors alone owing to lower R2 value (R2≦0.5712); residual collapse was negatively correlated with BD and DWT, linearly positively correlated with MFA, and had strongly positive linear correlation with RP. It is concluded that BD can be used as single factor (R2≥0.9412) to predicate unit cell wall shrinkage and RP is the relatively sound indicator for predicting residual collapse

The specific heat and resistance of CeCu6-xMx (M=Ni,Zn) have been studied in the concentration range where they still retain the orthorhombic structure. The coefficient c of -ln T term in resistance R = R-0+bT-clnT, as well as the gamma, have been found to vary in opposite directions with increasing x for Ni and Zn substitutions. The physical mechanism is discussed.

A series of layered (Sr1-xKx)Fe2As2 compounds with nominal x = 0-0.40 are synthesized by solid state reaction method. Similar to other parent compounds of iron-based pnictide superconductors, pure SrFe2As2 shows a strong resistivity anomaly near 210 K, which was ascribed to the spin-density-wave instability. The anomaly temperature is much higher than those observed in LaOFeAs and BaFe2As2, the two prototype parent compounds with ZrCuSiAs- and ThCr2Si2-type structures. K-doping strongly suppresses this anomaly and induces superconductivity. Like in the case of K-doped BaFe2As2, sharp superconducting transitions at Tc ~ 38 K is observed. We perform the Hall coefficient measurement, and confirm that the dominant carriers are hole-type. The carrier density is enhanced by a factor of 3 in comparison to F-doped LaOFeAs superconductor.

In this article, we reported a polarization orthogonal single-longitudinal-mode distributed Bragg reflector (DBR) fiber laser. The laser operated robustly in single longitudinal mode and dual polarizations with frequency difference of 976.93 MHz. This laser has simple structure as well as frequency adjustable. It can be used in a wide range of communication, sensor, and spectroscopic applications. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1658–1660, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23454

In this paper, we analyzed the frequency splitting phenomena when distributed Bragg reflector (DBR) fiber laser was influenced by lateral pressure. We gave the relationship of the frequency interval and the lateral pressure. This frequency splitting phenomena is based on Intracavity birefringent effects which are modulated by lateral pressure. So, this frequency splitting phenomena could be used in sensing pressure in the future. The pressure sensor which is based on the frequency splitting had more merits such as simple structure and frequency readable. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2628–2630, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22818

In order to put the Lead zinc niobate ceramics in practical use for low-temperature sintering multilayer capacitor (MLC), we have managed to reduce the sinter temperature of 0.85PZN-0.15BaTi3 ceramics by adding small amount of MgF2.SrF2. The results show that the sintering temperature can be reduced from 1100 °C to 900-950 °C, and meanwhile the dielectric constant versus temperature shows two peaks in the temperature range of -70 °C to 100 °C, near to the X7R character of capacitor. Frequency dispersion and dielectric loss are reduced down dramatically at -70 °C. These phenomena are different from that of typical relaxation ferroelectricity. The unusual dielectric behaviors could be clarified with the idea of superparaeletric state.

The specific heats of two nanocrystalline iron samples with different structures have been measured in the temperature range from 2 to 26 K. Experimental results show that the specific heat of nanocrystalline iron samples exhibits abnormal characteristic compared with that of standard bulk iron. The contributions of quantum size effect, surface mode and Einstein mode have been observed in the measurement. Through analyses, it is discovered that the relative density and particle size have a great influence on specific heat of nanocrystalline iron at low temperature.

The specific heat of nanocrystalline iron with grain size of 40 nm has been measured in the low temperature range from 1.8 to 26 K. The anomalous specific heat behavior of nanocrystalline iron is compared to that of the standard bulk iron. It is found that the electronic specific heat coefficient γ obtained at low temperatures decreases by about 50%. A T2 term in the heat capacity associated with surface modes has been clearly observed. A large enhancement of the specific heat at temperatures above 16 K may be interpreted as the Einstein oscillator contributions.

The specific heat of the recently discovered superconductor MgB2 has been measured at temperatures ranging from 4.5 to 80 K. The superconducting anomaly ΔC at Tc is clearly observed. The total specific heat in the normal state can be well fitted by electronic and phonon contributions. The Debye temperature θD is found to be 737 K, much larger than other intermetallic superconductors. The normal-state electronic specific heat coefficient γ is found to be 2.48±0.5 mJ/molK2 and ΔC/γTc is between 1.41 and 2.15.

Highly alternating CO2-cyclohexene oxide copolymer, namely poly(cyclohexene carbonate) (PCHC), considered potentially to be microelectronic sacrificial material, was successfully synthesized by copolymerization of cyclohexene oxide and CO2 in the presence of SalenAl(OiPr) catalyst. The obtained highly alternating PCHC copolymer were determined and proven to have superior thermal decomposition properties decomposing completely at 350 oC by thermogravimetric (TG) analysis under dynamic conditions. The thermal decomposition kinetics of the obtained PCHC was investigated by a different kinetic method using data from TG analysis. Based on the analytical, kinetic parameters were calculated and kinetic model of pyrolysis was proposed. TG-IR, Py-GC/MS, IR and 1H NMR techniques were applied to investigate the decomposition process. Based on Py-GC/MS and TG-IR techniques, carbon dioxide, 1,3-cyclohexadiene, cyclopentanecarboxaldehyde, cyclohexene oxide, cyclohexanone and trans-1,2- carbonyldioxycyclohexane were identified as thermal decomposition products of PCHC. The solid residues of the PCHC with 25% ether linkages decomposed at 200, 250, 300, 350 oC as determined by IR and 1H NMR. The results demonstrated that the carbonate content of the solid residues decreased gradually at elevated heat-temperatures and at 350 oC only few polyether linkages were observed.

Magnetoresistances of SrFe2As2 and BaFe2As2 in the magnetic ordered state are studied. Positive magnetoresistance is observed in the magnetic fields H applied in the azimuthes of θ = 0° and 30° with respect to the c-axis. The magnetoresistance can reach 20% for SrFe2As2 and 12% for BaFe2As2 at H = 9 T with θ = 0° (H || c). Above the magnetic transition temperature, the magnetoresistance becomes negligible. The data in the magnetic ordered state could be described by a modified two-band galvanomagnetic model including the enhancement effect of the applied magnetic field on the spin-density-wave gap. The field enhanced spin-density-wave gaps for different types of carriers are different. Temperature dependencies of the fitting parameters are discussed.

The specific heat of the emeraldine base form of polyaniline and the emeradine salt of polyaniline has been measured at temperatures between 1.8 and 45K. The experimental results have been interpreted in terms of the contributions from both the crystalline and the amorphous phases characterizing the polymer. Anomaly of the specific heat, which is much larger than that expected from the Debye theory, has been successfully explained by the phonon-fracton model at low temperatures. The electronic specific heat has not been observed from the present data.

Specific heat of the bulk amorphous Zr-Ti-Cu-Ni-Be alloy and different heat-treated samples has been measured in temperature range from 4.5 to 30K. The specific heat result can be well fitted by electronic and phonon contributions. The value of electronic specific coefficient γ is much bigger than other samples and the Debye temperature ΘD increases regularly from amorphous to equilibrium crystallized phase. The different behaviors of different samples are interpreted primarily in terms of electronic density of states and Debye model.

CeNiSn is an interesting heavy fermion compound,with its ground state being a Kondo insulator.The effect of the substitution of Ni by Cu on the specific heat of CeNi1-xCuxSn polycrystal samples is studied through the m ethod of chemical element substitution.A series of samples (x=00,0.02,0.06,0.0 6) were prepared with an electric arc furnace in the atmosphere of flowing high purity argon gas.X-ray powder diffraction analysis shows that all the final samp les have single-phase structure,and that,with the increase of the substitution a mount of Ni,the crystal parameters of the samples become larger.The specific hea t measurements were performed with an adiabatic colorimeter.The results indicate that the doping of Cu increases the specific heat at low temperature,and that t he V-shape gap is gradually suppressed.The physical mechanism may be that the do ping of copper brings about the Kondo lattice discorder and the increase in 3d e lectrons.