梯度复合SiC/C面向等离子体材料的制备与表征

利用粉末冶金方法,完成了SiC和C两种难烧结物质的同步烧结,制备出了SiC成分分布从0％～100％的接近理论密度的SiC/C FGM,显微观察显示材料的成分和结构是呈梯度分布的。材料将SiC的良好的耐腐蚀性和石墨的良好的抗热冲击性结合在一起,并具有较高的有效热导和良好的抗热疲劳能力,化学溅射和Tokamak原位等离子体辐照结果显示材料具有良好的耐高温等离子体冲刷性能。     

Optical injection locking of a 38-GHz-band InP-based HEMToscillator using a 1.55-μm DSB-SC modulated lightwave

Optical injection locking was experimentally performed using a 38-GHz-band InP-based HEMT MMIC oscillator and a 1.55-μm lightwave. Two optical modulation schemes were compared for optical injection locking, and no difference was found except for the optical modulation frequency. With suppressed carrier modulation of the lightwave, phase noise of less than -73.2 dBc/Hz at a 10-kHz frequency offset and a 14-MHz locking range were achieved     

SiC/C功能梯度材料的制备和评价

以粉末冶金方法制备了块体SiC／Ｃ ＦＧＭ,该材料结合了SiC的耐腐蚀、抗冲刷和石墨的高抗热冲击性能,具备良好的抗热疲劳性能,拓展了ＳiC陶瓷的应用前景．     

Fabrication of nanostructured titania on flexible substrate by electrochemical anodization

Titanium films were deposited on ITO (indium tin oxide)-coated PEN (polyethylene naphthalate) and flexible clay substrates by ion beam sputter deposition method. The surface morphology of the deposited films was smooth on PEN and rough on clay substrates. The titanium film deposited on Clay-mo (98% montmorillonite) substrate was anodized in ethylene glycol + 2 vol% H₂O + 0.3 wt% NH₄F solution, and the titanium films deposited on Clay-st (99% stevensite) substrate was anodized in 2-propanol + 16 vol% H₂O + 0.14 M NH₄F solution. Then nanohole-structured titania (TiO₂) films were firstly and successfully fabricated on the flexible transparent clay substrates. The nanohole structures of TiO₂ on both clay substrates were similar to those on PEN and glass substrates. The TiO₂ nanohole structure was almost maintained after annealing at 450 °C for 4 h in air. The optical transmittance of the nanohole-structured TiO₂ films on Clay-st increased from 26% to 54% at 800 nm in wavelength after annealing at 450 °C for 1 h in air.     

Proton conduction and chemical stability of (La0.5Sr0.5)(Mg0.5+yNb0.5−y)O3−δ

Electrical conduction properties of complex perovskite-type oxides in the (La_0.5Sr_0.5)(Mg_0.5+yNb_0.5−y)O_3−δ (y = 0.02-0.06) series at intermediate-high temperatures were investigated; introduction of protons by hydration of oxide-ion vacancies was expected by increasing the Mg/Nb ratio from unity. The conductivity depended on y and a maximum conductivity was obtained at y = 0.04: σ = 4.9 × 10⁻⁶ S cm⁻¹ at 400 °C in wet H₂ atmospheres. From electromotive force measurements of hydrogen and water vapor concentration cells, electrical conduction in wet H₂ atmospheres can be attributed to ionic conduction, and proton conduction is dominant below 700 °C. Unlike other perovskite-type proton conductors, (La_0.5Sr_0.5)(Mg_0.54Nb_0.46)O_3−δ was stable in CO₂ atmospheres even in the low-intermediate temperature region due to dilution of reactive strontium by lanthanum.     

Expression of Aspergillus oryzae phytase gene in Aspergillus oryzae RIB40 niaD(-)

Aspergillus oryzae RIB40 niaD(-) was transformed using a plasmid constructed with the A. oryzae phytase gene and pNAN8142 vector. The culture broth of the transformant, which was grown in a medium containing starch as a carbon source and polyvinylpyrrolidone showed phytase activity of a maximum of 2.0 units ml(-1) at 37 degrees C, pH 5.5.     

A New Precision Digital Phase Meter and Its Simple Calibration Method

A digital phase meter (DPM) for power frequencies with a very low measurement uncertainty of 1 $muhbox{rad}$ was developed at Japan Electric Meters Inspection Corporation (JEMIC) to establish a power and energy calibration system. We also developed a phase meter calibrator (PMC) for calibrating the DPM. Since the DPM and PMC are synchronized with a single clock, the DPM can be calibrated by a very simple measurement method, which no longer requires extra standards. The DPM has been employed as an instrument for the primary standard of power and energy in Japan to achieve precise phase angle measurement. Since the error in the power measurement at power factor 0 is equal to the error in the phase angle measurement, we verified the performance of the DPM by calibrating a standard power meter using the power calibrators at JEMIC and Physikalische-Technische Bundesanstalt (PTB), and comparing the test results at power factor 0. According to the measurement, the phase angle difference between JEMIC and PTB is within 7 $mu hbox{rad}$.      

Composite Behavior of Lath Martensite Steels Induced by Plastic Strain,a New Paradigm for the Elastic-Plastic Response of Martensitic Steels

Based on high-resolution neutron diffraction experiments, we will show that in lath martensite steels, the initially homogeneous dislocation structure, i.e., homogeneous on the length scale of grain size, is disrupted by plastic deformation, which, in turn, produces a composite on the length scale of martensite lath packets. The diffraction patterns of plastically strained martensitic steel reveal characteristically asymmetric peak profiles in the same way as has been observed in materials with heterogeneous dislocation structures. The quasi homogeneous lath structure, formed by quenching, is disrupted by plastic deformation producing a composite structure. Lath packets oriented favorably or unfavorably for dislocation glide become soft or hard. Two lath packet types develop by work softening or work hardening in which the dislocation densities become smaller or larger compared to the initial average dislocation density. The decomposition into soft and hard lath packets is accompanied by load redistribution and the formation of long-range internal stresses between the two lath packet types. The composite behavior of plastically deformed lath martensite opens a new way to understand the elastic-plastic response in this class of materials.     

Work Hardening,Dislocation Structure,and Load Partitioning in Lath Martensite Determined by <Emphasis Type="Italic">In Situ</Emphasis> Neutron Diffraction Line Profile Analysis

A lath martensite steel containing 0.22 mass pct carbon was analyzed in situ during tensile deformation by high-resolution time-of-flight neutron diffraction to clarify the large work-hardening behavior at the beginning of plastic deformation. The diffraction peaks in plastically deformed states exhibit asymmetries as the reflection of redistributions of the stress and dislocation densities/arrangements in two lath packets: soft packet, where the dislocation glides are favorable, and hard packet, where they are unfavorable. The dislocation density was as high as 10¹⁵ m^?2 in the as-heat-treated state. During tensile straining, the load and dislocation density became different between the two lath packets. The dislocation character and arrangement varied in the hard packet but hardly changed in the soft packet. In the hard packet, dislocations that were mainly screw-type in the as-heat-treated state became primarily edge-type and rearranged towards a dipole character related to constructing cell walls. The hard packet played an important role in the work hardening in martensite, which could be understood by considering the increase in dislocation density along with the change in dislocation arrangement.     

Efficacy of acidified sodium chlorite treatments in reducing Escherichia coli O157:H7 on Chinese cabbage

Efficacy of acidified sodium chlorite for reducing the population of Escherichia coli O157:H7 pathogens on Chinese cabbage leaves was evaluated. Washing leaves with distilled water could reduce the population of E. coli O157:H7 by approximately 1.0 log CFU/g, whereas treating with acidified chlorite solution could reduce the population by 3.0 log CFU/g without changing the leaf color. A similar level of reduction was achieved by washing with sodium chlorite solution containing various organic acids. However, acidified sodium chlorite in combination with a mild heat treatment reduced the population by approximately 4.0 log CFU/g without affecting the color, but it softened the leaves. Moreover, the efficacy of the washing treatment was similar at low (4 degrees C) and room (25 degrees C) temperatures, indicating that acidified sodium chloride solution could be useful as a sanitizer for surface washing of fresh produce.