Transport properties for a dilute solution of3He in two-dimensional liquid4He

The temperature variations of the diffusion coefficientD(T), thermal diffusion ratio k _T (T) and thermal conductivity (T) in a dilute solution of³He atom in two-dimensional liquid helium are evaluated explicitly by solving the kinetic equations via phonon-phonon, phonon-roton, roton-roton, impurityelementary excitation and impurity-impurity scatterings. In the low-temperature region, the main contributions toD(T) and (T) come from the interactions between phonons and impurities, while in the high-temperature region the interactions between impurities and whole elementary excitations contribute more strongly toD(T) and (T) than those of only elementary excitations. For a dilute solution, the thermal diffusion ratio k _T (T), neglecting the internal mass counterflow, is much smaller than the effective thermal diffusion ratio k _T ^* (T), which is a function of thermostatic properties. The effective thermal conductivity _eff is much larger than the thermal conductivity and has different temperature dependence from the thermal conductivity. The behaviors of the two-dimensional diffusion coefficient and thermal conductivity are much like the bulk case, where they exhibit exponential decay with increasing temperature, although they are much smaller than those of the bulk case.     

Temperature and frequency effects on fatigue crack growth of uPVC

Temperature and frequency effects on fatigue crack growth rate have been modelled. The stress intensity factor- biased Arrhenius equation and a result from the two-stage zone model have been incorporated into the present model. Subsequently, temperature and frequency effects on fatigue crack growth in unplasticized polyvinyl chloride (uPVC) were studied over a temperature range 15–55 °C and a frequency range 0.01–10 Hz. Data for PVC taken from the literature were also included for analysis. It was found that the predicted values from the proposed model are in good agreement with experimental results.     

Effect of deposition temperature on dielectric properties of PECVD Ta2O5 thin film

Tantalum oxide film formation by plasma-enhanced chemical vapour deposition (PECVD) using TaCl₅ as a source material was examined. The effects of deposition temperature on the formation, structure and electric properties of the Ta₂O₅ film were investigated for Al/Ta₂O₅/ p-Si (MTS) capacitors. The deposition rate and refractive index increased with increasing deposition temperature. It was found that the structure of Ta₂O₅ deposited by PECVD was amorphous as-deposited. However, crystalline -Ta₂O₅ of hexagonal structure was formed by a 700 °C, 1 h heat treatment in argon. Capacitance and relative dielectric constant of the PECVD Ta₂O₅ were found to be 2.54 fF m^–2 and 23.5, respectively. The PECVD films obtained in this study have higher dielectric constants and remarkably better general film characteristics than those obtained by other deposition methods.     

The effect of alternative product-label design on warning compliance

Many potentially hazardous products are packaged in small containers. Because of the limited amount of space available on these containers for warnings and other information, manufacturers often reduce the size and amount of printed material on the labels. This frequently impairs the message's legibility, noticeability and comprehensibility. Recently, several alternative label designs have been investigated using preference ratings, but whether the designs facilitate safer behaviour has not been determined. In the present experiment, two alternative designs (tag and wings) were compared with a conventional (control) design for their effect on behavioural compliance with a warning on a very small container of glue. Participants performed a parts-assembly task using the glue without being informed of the study's real purpose. Whether participants wore protective gloves as directed by the warning was measured. Results showed that the tag design produced significantly greater compliance than the other two designs. Measures of noticing, reading and recall of the warning mirrored the compliance results. While participants generally preferred the control label, they most preferred the tag warning. Overall, the results suggest that alternative designs like the tag can enhance warning communication and compliance in cases where surface area is limited.     

Intelligent judge neural network for speech recognition

An intelligent judge neural network (IJNN) is developed to make decisions out of contradictory arguments, which may come from different classifiers with different characteristics and/or input features. For speech recognition applications a multi-layer perceptron classifies the word as a spectro-temporal pattern, while a neural prediction model or hidden-control neural network relies on dynamic nature of the speech signal. The judge≓ accepts input values from the lower-level neural network classifiers and provides ruling verdicts. Two intelligent judges have been investigated. The neuro-judge≓ rules by extracting decision rules from training data, i.e. disputes between the two classifiers, while the fuzzy-judge≓ just utilizes min-max operations. The IJNN demonstrates better recognition rates. More importantly its performance is much less sensitive to the choice of training data.     

Preparation and characterization of poly(2,6-dimethyl-1,4-phenylene oxide) and Nylon 6 graft copolymer

Summary A poly(2,6-dimethyl-1,4-phenylene oxide) (PPO, 1) macroinitiator having carbonylcaprolactam groups was prepared through metalation of methyl group of PPO and subsequent modification to introduce carboxyl group, acid chloride group, and finally carbonylcaprolactam group. Anionic ring opening copolymerization of -caprolactam took place onto the macroinitiator to give a graft copolymer of PPO and Nylon 6. The structure of intermediate materials and the graft copolymer were characterized by ¹H NMR, ¹³C NMR, and IR spectroscopy. Glass transition temperatures and melting temperatures of these materials are also reported. It is found that the copolymer has a microphase-separated morphology even with segment molecular weight as low as 3000.     

Successful fabrication of bicrystal Si substrates for YBa2Cu3O7 − y Josephson junctions

Bicrystal Si(BiSi) substrates for grain boundary (GB) Josephson junctions (GBJJs) have been fabricated by a direct bonding technique using a hot press method. The fracture strength and structure of the bonding interfaces were investigated to obtain substrates suitable for the junctions. It was found that an increase in the pressure of the hot press improves the reproducibility of the GBJJs. YBa₂Cu₃O_{7 − y} GBJJs were successfully fabricated on Bi-Si substrates with a misorientation angle of 15 ° bonded under a pressure of 90 kgf cm⁻² at 1200 °C in a vacuum of ≈10⁻³ Pa. These junctions showed typical I-V curves described by the RSJ model. The Shapiro steps induced by millimetre wave irradiation of 101 GHz were clearly observed in the I-V curves up to 3 mV, corresponding to at least 1.5 THz (, where e is the unit charge, V the voltage and h Planck's constant).     

Analysis of lidar backscatter profiles in optically thin clouds

The solution of the lidar equation for profiles of backscatter and extinction in optically thin clouds is constrained by values of the cloud transmittance determined from the elastically scattered lidar signals below and above the cloud. The method is extended to those cases in which an aerosol layer lies below or above the cloud layer. Examples are given in both cases. An analytical expression for the average lidar ratio in the cloud is derived for those cases in which molecular scattering is significant.