The firm as a bundle of barcodes

We empirically investigate the firm growth model proposed by Buldyrev et al. by using a unique dataset that contains the daily sales of more than 200 thousand products, which are collected from about 200 supermarkets in Japan over the last 20 years. We find that the empirical firm growth distribution is characterized by a Laplace distribution at the center and power-law at the tails, as predicted by the model. However, some of these characteristics disappear once we randomly reshuffle products across firms, implying that the shape of the empirical distribution is not produced as described by the model. Our simulation results suggest that the shape of the empirical distribution stems mainly from the presence of relationship between the size of a product and its growth rate.     

Anisotropic spin fluctuations and superconductivity in "115" heavy fermion compounds: ⁵⁹Co NMR study in PuCoGa₅

We report results of ??Co nuclear magnetic resonance measurements on a single crystal of superconducting PuCoGa? in its normal state. The nuclear spin-lattice relaxation rates and the Knight shifts as a function of temperature reveal an anisotropy of spin fluctuations with finite wave vector q. By comparison with the isostructural members, we conclude that antiferromagnetic XY-type anisotropy of spin fluctuations plays an important role in mediating superconductivity in these heavy fermion materials.     

Power-generating property of direct CH4 fueled SOFC using LaGaO3 electrolyte

A composite anode of NiFe–MgO (2.5 wt.%)–La_0.9Sr_0.1Ga_0.8Mg_0.2O₃ (LSGM) (10 wt.%) for solid oxide fuel cells using directly CH₄ as fuel was studied. Compared with previously reported NiFe–LSGM (10 wt.%) cermet anode, the NiFe–MgO–LSGM anode exhibited superior power generation performance, stability under CH₄ atmosphere at 973 K, and high tolerance against the carbon deposition. These improvements by the additives are explained by the increase in basic property of anode material. The anode activity of NiFe–MgO–LSGM cermet for CH₄ fuel is still lower than that for H₂ one. However, comparing with that of NiFe–LSGM cermet, anodic overpotential slightly decreased by the addition of MgO, suggesting the improved surface activity.     

Performance of compact pulse radiolysis system using a photocathode RF gun

A compact pulse radiolysis system using a photocathode RF gun was installed at Sumitomo Heavy Industries. Some performance tests were conducted concerning the electron beam and the laser pulse. The energy and the per-pulse charge of the electron beam were measured to be 1.75 MeV max. and 1 nC. The fluctuation of the charge was restricted within 2%. The pulse widths of the electron pulse and the analyzing laser pulse were 20 ps and 15 ps, respectively. The timing jitter between electron pulse and the laser pulse was ±5.7 ps. Based on these measurements, the all-over time resolution can deduced to be about 25 ps.     

Band-tail model and temperature-induced blue-shift in photoluminescence spectra of InxGa1-xN grown on sapphire

A band-tail model of inhomogeneously broadened radiative recombination is presented and applied to interpret experimental data on photoluminescence of various bulk and quantum-well epitaxial InGaN/GaN structures grown by MOCVD. The temperature dependence of the spectral peak position is analyzed according to the model, explaining the anomalous temperature-induced blue spectral shift. Significant differences are observed between epilayers grown on sapphire substrates and on GaN substrates prepared by the sublimation method. No apparent evidence of band tails in homoepitaxial structures indicates their higher crystalline quality.     

A method for achieving electromagnetic wave absorption by low-loss stratified construction materials

For the safe and effective use of electromagnetic waves, a method for designing construction materials having selective electromagnetic wave absorption is needed. As an example, the characteristics of a stratified construction material consisting of two different low-loss materials (acrylic resin and glass) is evaluated by numerical simulation, and the electromagnetic wave absorption mechanism is determined. Furthermore, a method is developed for designing stratified construction materials to realize electromagnetic wave absorption at a desired frequency.     

Multi-Input Floating Gate Differential Amplifier and Application to Intelligent Sensors

Multi-input floating gate differential amplifier (FGDA) is proposed which can perform any convolution operation with differential structure and feedback loop. All operations are in the voltage mode. Only one terminal is required for the negative feedback which can suppress distortions due to mismatches of active elements. Possible applications include intelligent image sensor, where fully parallel DCT operation can be performed. A prototype chip is fabricated which is functional. A preliminary test result is reported.     

神经网络扩展滤波训练及色氨酸的选择测定

前馈神经网络ＮＮ应用甚广，经典及传算法ＢＰ存在收敛慢及局部优点等缺陷。为此提出了新的快速高效学习算法即，（ＥＦ）扩展卡曼滤波（ＥｘｔｅｎｄｅｄＫａｌｍａｎＦｉｌｔｅｉｎｇ，ＥＦ），用于色氨酸选择测定及氨基酸同时测定，结果良好。     

Correlation between burning surface temperature and regression rate for polymethylmethacrylate

Prediction of the regression rate of polymeric fuels is important, especially for the optimal design of solid fuel ramjets or hybrid rocket motors. The burning surface temperature and the surface activation energy in the Arrhenius pyrolysis equation are required for prediction of the regression rate. As a typical polymeric fuel, polymethylmethacrylate (PMMA) was chosen for the present study. The burning surface temperature of PMMA was measured for both end-burning and sandwich-burning experimental devices. In the end-burning experiment, the oxygen flow impinged on the top of the specimen to burn the PMMA. In the sandwich-burning experiment, PMMA sheets were sandwiched between AP pellets. Temperature profiles near the burning surface were measured with a thermocouple embedded in the specimen. Simultaneously, the emergence of the thermocouple from the burning surface was determined with a video camera. The burning surface temperature obtained in the present study was found to be almost independent of the regression rate. The surface activation energy of PMMA was more than 1000 kJ/mol. Our measured surface temperature or the activation energy differs from the values measured with a thermocouple in previous studies. This difference probably is a result of mistaken identification of the burning surface temperature in the previous studies, because it was found that the sudden change or tiny plateau of the slope, in the temperature profile of PMMA, did not signal the burning surface.     

Stratigraphy of the Middle-Upper Permian and Lowermost Triassic at Chaotian,Sichuan, China: Record of Late Permian double mass extinction event

Precise stratigraphic analysis of Middle-Upper Permian and Lower Triassic sequence at Chaotian in northern Sichuan, China, identified two remarkable mass extinction horizons, one at the Middle-Upper Permian (Guadalupian-Lopingian; G-L) boundary and the other at the Upper Permian-Lower Triassic (P-T) boundary. Across each of the boundaries, biodiversity declined sharply in fusulinid, rugose coral, brachiopod, ammonite, conodont, and radiolaria. Both boundaries are characterized by two biohorizons, i.e., one marked by major extinction of pre-existing fauna and the other by the first appearance of younger fauna. It is noteworthy that a peculiar rhyo-dacitic tuff bed occurs at each of the extinction horizons. Thus the Late Permian biosphere was strongly affected twice by highly explosive, severe volcanism. Regional correlation of the G-L and P-T boundary tuff beds throughout South China, and partly to Japan, positively suggests a cause-effect link between large-scale explosive volcanism and mass extinction.