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21.
This paper reports the prediction of the ethylene content (C2 content) in random polypropylene (RPP) and block polypropylene (BPP) in the melt state by near-infrared (NIR) spectroscopy and chemometrics. NIR spectra of RPP and BPP in the melt states were measured by a Fourier transform near-infrared (FT-NIR) on-line monitoring system. The NIR spectra of RPP and BPP were compared. Partial least-squares (PLS) regression calibration models predicting the ethylene (C2) content that were developed by using each RPP or BPP spectra set separately yielded good results (SECV (standard error of cross validation): RPP, 0.16%; BPP, 0.31%; correlation coefficient: RPP, 0.998; BPP, 0.996). We also built a common PLS calibration model by using both the RPP and the BPP spectra set. The results showed that the common calibration model has larger SECV values than the models based on the RPP or the BPP spectra sets individually and is not practical for the prediction of the C2 content. We further investigated whether a calibration model developed by using the BPP spectra set can predict the C2 contents in the RPP sample set. If this is possible, it can save a significant amount of work and cost. The results showed that the use of the BPP model for the RPP sample set is difficult, and vice versa, because there are some differences in the molar absorption coefficients between the RPP and BPP spectra. To solve this problem, a transfer method from one sample spectra (BPP) set to the other spectra (RPP) set was studied. A difference spectrum between an RPP spectrum and a BPP spectrum was used to transfer from the BPP calibration set to the RPP calibration set. The prediction result (SEP (standard error of prediction), 0.23%, correlation coefficient, 0.994) of RPP samples by the transferred calibration set and model showed that it is possible to transfer from the BPP calibration set to the RPP calibration set. We also studied the transfer from the RPP calibration set (the range of C2 content: 0-4.3%) to the BPP calibration set. The prediction result of C2 content (the range of C2 contents: 0-7.7%) in BPP by use of the calibration model based on the transferred BPP spectra from the RPP spectra showed that the transfer method is only effective for the interpolation of the C2 content range by the nonlinear change in the peak intensities with the C2 content. 相似文献
22.
M. Tanaka K. Ozaki H. Nishino H. Ebe Y. Miyamoto 《Journal of Electronic Materials》1998,27(6):579-582
We employed AgNO3 solutions for doping Ag in liquid phase epitaxy (LPE) grown Hg0.78Cd0.22Te epilayers and found that the minority carrier lifetimes became longer so that the diode properties improved. After annealing
LPE grown Hg(1-x)Cd(x)Te layers (x=0.22) in Hg atmosphere, the epilayers were immersed in an AgNO3 solution at room temperature. The typical carrier concentrations of holes was 3 × 1016 cm−3 at 77K. These values were almost the same as for the nondoped wafers. Also, its acceptor level was 3 to 4 meV. This shows
that the Ag was activated. The doped crystals have lifetimes several times longer than those of the nondoped crystals. Numerical
fitting showed the lifetime was limited mostly by the Auger 7 process. The Shockley-Read-Hall recombination process was not
effective. To examine the Ag-doped wafer, we fabricated photodiodes using standard planar technology. The diodes have an average
zero-bias resistance of several MΩ and a shunt resistance of about 1 GΩ for a 10 μm cutoff wavelength at 78K. These values
are about four times higher than those of nondoped diodes. The photo current is also two times higher at the same pixel size.
This shows that the quantum efficiency is increased. The extension of the lifetime contributes to the high resistance and
the high quantum efficiency of the photodiode. 相似文献
23.
Superoleophobic thin films have many potential applications including fluid transfer, fluid power systems, stain-resistant and antifouling materials, and microfluidics. Transparency is also desired with superhydrophobicity for numerous applications; however, transparency and oleophobicity are almost incompatible with each other from the point of view of surface structure. Oleophobicity requires a rougher structure on the nano–microscale than hydrophobicity, and this rough structure brings light scattering. So far, there are few reports of compatible transparency and superoleophobicity. In this report, we propose see-through-type fabrics having nanoparticle-based hierarchical structure thin films to improve both oleophobicity and transparency. The vacant space between the fibers of the fabric has two important roles: to allow light to pass through and to induce an air layer to produce a Cassie state of a liquid droplet on the resulting thin film. To realize a low surface energy and nanoscale rough structured surface on fabric fibers, we used a spray method with perfluoroalkyl methacrylic copolymer, silica nanoparticles, and volatile solvent. Scanning electron microscopy images revealed that hierarchical nanoparticle structures were uniformly formed on the fabrics. The transparency of the obtained thin film was approximately 61 %, and the change of transparency between the non-coated and coated fabrics was 11 %. The contact angles of oil (rapeseed oil and hexadecane) and water droplets on the fabricated film were observed to be over 150° during investigation of its surface wettability. 相似文献
24.
In vivo measurement of swallowing by monitoring thyroid cartilage movement in healthy subjects using thickened liquid samples and its comparison with sensory evaluation
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25.
Takafumi Ishii Takuya Maie Naofumi Kimura Yuki Kobori Yasuo Imashiro Jun-ichi Ozaki 《International Journal of Hydrogen Energy》2017,42(23):15489-15496
The use of carbon cathode catalysts in polymer electrolyte fuel cells instead of the current platinum catalysts is attracting increasing attention. We claim that two factors are important for enhancing the activity of carbon cathode catalysts in the oxygen reduction reaction (ORR): the formation of a nanoshell structure and co-doping with boron and nitrogen. Herein, we investigate the preparation and characterization of active ORR carbon catalysts that combine the above factors. Boron and nitrogen (BN)-doped nanoshell-containing carbon (BN-NSCC) was prepared by carbonizing a mixture of poly(furfuryl alcohol), cobalt phthalocyanine, melamine, and a trifluoroborane–methanol complex at 1000 °C. Transmission electron microscopy and X-ray photoelectron spectroscopy revealed the formation of nanoshell structures with distorted graphitic layers and the introduction of boron and nitrogen atoms, respectively. The ORR activity was evaluated in oxygen-saturated 0.5 mol dm?3 H2SO4 using Koutecky–Levich analysis. The BN-NSCC showed an eight to ten times higher ORR activity than undoped NSCC, with an increased number of electrons participating in the reaction. Tafel analysis revealed a change in the rate-determining step caused by BN-doping. Thus, the combination of a nanoshell structure and co-doping with boron and nitrogen was found to improve the ORR activity of carbon catalysts. 相似文献
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29.
In this study, we apply the finite element method to investigate precursor to frictional sliding phenomena arising immediately prior to macroscopic stick–slip transitions in elastic bodies within the framework of a continuum theory. Using a numerical model that mimics an actual experimental system, we study the behavior of contact surface nodes to assess the influence of stiffness, driving velocity, initial conditions, and discretization conditions on the propagation characteristics of microscopic slips. In particular, we show that the initial distribution of frictional stress arising due to the Poisson effect has a significant effect on the propagation characteristics in slip regions. Next, based on the results of a finite element analysis of precursor phenomena that accounts for the influence of bulk compliance, we consider the determination of parameters in rate-dependent friction models. With regard to the behavior of sliding friction, we show that the relationship between friction tests and friction models is fundamentally different from the relationship between material tests and constitutive models for material deformation. We conclude that a proper understanding and classification of friction tests, friction models, and the relationship between these tests and boundary value problems are crucial ingredients in the application of computer-aided engineering techniques to sliding-friction phenomena; indeed, friction tests must ultimately be treated as boundary value problems. 相似文献
30.
Daisuke Yamamoto Takeshi Ozaki Carlos A. R. Sá de Melo Ippei Danshita 《Journal of Low Temperature Physics》2014,175(1-2):258-264
We study a first-order phase transition between superfluid and Mott insulator phases in binary Bose mixtures loaded into a hypercubic optical lattice. The system is described by a two-component Bose-Hubbard model. Considering the difference between the two kinds of bosons in the intra-component interaction strength, we discuss the metastability of the system and the hysteresis associated with the first-order superfluid-Mott insulator transition. It is found that the sweeping of hopping amplitude induces a conventional hysteresis-loop behavior. We also find an anomalous hysteresis behavior when the chemical potential is varied. In the anomalous hysteresis, the phase transition occurs in a unidirectional way and a hysteresis loop does not form. 相似文献