Morphological Effects of Grinding on Bismuth-Based Cuprate Superconductors

Morphological changes of bismuth-based cuprate superconductors, such as the 2223 phase, via a small mechanical force were studied mainly by means of high-resolution transmission electron microscopy and atomic force microscopy. Even light mechanical grinding of the sintered 2223 samples led to the formation of superfine particles that had a width of ∼5 nm. Moreover, we found first that the superfine particles had a discrete thickness of odd numbers of a half unit length c /2 of the 2223 phase, e.g. 1.9 nm, 5.6 nm, and so on. The formation of the superfine particles was due to cleavage at Bi—O double layers that were bound weakly to each other in a unit cell.     

Application of land use regression to regulatory air quality data in Japan

A land use regression (LUR) model has been used successfully for predicting traffic-related pollutants, although its application has been limited to Europe and North America. Therefore, we modeled traffic-related pollutants by LUR then examined whether LUR models could be constructed using a regulatory monitoring network in Shizuoka, Japan. We used the annual-mean nitrogen dioxide (NO₂) and suspended particulate matter (SPM) concentrations between April 2000 and March 2006 in the study area. SPM accounts for particulate matter with an aerodynamic diameter less than 8 μm (PM₈). Geographic variables that are considered to predict traffic-related pollutants were classified into four groups: road type, traffic intensity, land use, and physical component. Using geographical variables, we then constructed a model to predict the monitored levels of NO₂ and SPM. The mean concentrations of NO₂ and SPM were 35.75 μg/m³ (standard deviation of 11.28) and 28.67 μg/m³ (standard deviation of 4.73), respectively. The final regression model for the NO₂ concentration included five independent variables. R² for the NO₂ model was 0.54. On the other hand, the regression model for the SPM concentration included only one independent variable. R² for the SPM model was quite low (R² = 0.11). The present study showed that even if we used regulatory monitoring air quality data, we could estimate NO₂ moderately well. This result could encourage the wide use of LUR models in Asian countries.     

Great earthquake East Japan observation by superconducting gravimeter in Antarctica

The seismic wave caused by the Great East Japan Earthquake that occurred on March 11, 2011 at 14:46 JST (magnitude: M 9.0, location: 38° 6.2 min N, 142° 51.6 min E, depth: 32 km) was clearly observed approximately 20 min later by the superconducting gravimeter at Syowa Station, about 14,000 km away from Japan. The observation of the free oscillations of the Earth will be reported compared to the observed records of the Sumatra earthquake on December 26, 2004 (magnitude: M 9.1) and Chile earthquake on February 27, 2010 (magnitude: M 8.8).     

Effect of Fe and partial pressure of oxygen on the formation and phase transformation behavior of Al2O3 scale

The effect of oxygen partial pressure on the phase transformation of Al₂O₃ scale on various Fe–Al alloys with and without very thin (～100 nm) Fe coating was investigated. Fe‐coating on Fe–Al alloys can effectively suppress metastable Al₂O₃ formation, but little effect was observed when the samples were oxidized in a low partial pressure of oxygen. Under the low ${\rm P}_{{\rm O}_{{\rm 2}} } $ atmosphere, metastable to stable α‐Al₂O₃ scale phase transformation on both Fe‐coated and non‐coated Fe–Al alloys was significantly delayed. The lattice spacing of α‐Al₂O₃ scale formed in air decreased with increasing alloy Al content. Further decrease in the lattice spacing of α‐Al₂O₃ scale was observed when the alloy was oxidized in low ${\rm P}_{{\rm O}_{{\rm 2}} } $ . The results obtained clearly indicated that the formation of Fe₂O₃ or Fe³⁺ in metastable Al₂O₃ accelerated the metastable to stable α‐Al₂O₃ scale transformation.     

挤出机预热阶段等时控温系统研究与实现

设计了一种新的挤出机料筒预热过程各个加热段等时控温系统。该系统采用了晚启动加上自整定PID控制的等时控温策略,实现了挤出机预热阶段各个加热段等时到达设定温度值,并且控温的精度比起现有大部分机器上的单点式控温方式有了较大的提高。整个系统设计分为上位机监测控制以及数据采集软件设计和下位机智能控制平台设计。经实践验证,采用该温控系统可以减少挤出机料筒预热阶段加热的总时间,大大节约了能源。     

Image-processing technique for suppressing ribs in chest radiographs by means of massive training artificial neural network (MTANN)

When lung nodules overlap with ribs or clavicles in chest radiographs, it can be difficult for radiologists as well as computer-aided diagnostic (CAD) schemes to detect these nodules. In this paper, we developed an image-processing technique for suppressing the contrast of ribs and clavicles in chest radiographs by means of a multiresolution massive training artificial neural network (MTANN). An MTANN is a highly nonlinear filter that can be trained by use of input chest radiographs and the corresponding "teaching" images. We employed "bone" images obtained by use of a dual-energy subtraction technique as the teaching images. For effective suppression of ribs having various spatial frequencies, we developed a multiresolution MTANN consisting of multiresolution decomposition/composition techniques and three MTANNs for three different-resolution images. After training with input chest radiographs and the corresponding dual-energy bone images, the multiresolution MTANN was able to provide "bone-image-like" images which were similar to the teaching bone images. By subtracting the bone-image-like images from the corresponding chest radiographs, we were able to produce "soft-tissue-image-like" images where ribs and clavicles were substantially suppressed. We used a validation test database consisting of 118 chest radiographs with pulmonary nodules and an independent test database consisting of 136 digitized screen-film chest radiographs with 136 solitary pulmonary nodules collected from 14 medical institutions in this study. When our technique was applied to nontraining chest radiographs, ribs and clavicles in the chest radiographs were suppressed substantially, while the visibility of nodules and lung vessels was maintained. Thus, our image-processing technique for rib suppression by means of a multiresolution MTANN would be potentially useful for radiologists as well as for CAD schemes in detection of lung nodules on chest radiographs.     

Surface modification of graphitized carbonaceous materials by electropolymerization of thiophene and their effects on electrochemical properties

Highly oriented pyrolytic graphite (HOPG) and graphitized carbonaceous thin films prepared by plasma-assisted chemical vapor deposition (PACVD) were surface-modified by electropolymerization of thiophene. The electrochemical properties of the carbonaceous materials were studied by cyclic voltammetry and ac impedance spectroscopy. Irreversible cathodic current of the carbonaceous materials above 0.5 V (vs. Li/Li⁺) in the cyclic voltammograms significantly decreased by electropolymerization of thiophene, indicating that electropolymerization of thiophene suppress the decomposition of electrolytes on the carbonaceous materials. On the Nyquist plots, a semi-circle due to surface film resistance was observed, and the value significantly decreased at around 1.5 V. At potentials below 0.9 V, another semi-circle appeared in the middle to lower frequency region, which was assigned to the charge transfer resistance due to lithium-ion transfer at the surface-modified carbon electrode/electrolyte interface. The charge-transfer resistances were dependent on electrode potentials. The activation energy for lithium-ion transfer through interface between the surface-modified HOPG electrode and electrolyte was evaluated, and the value was almost identical to that obtained for an untreated HOPG electrode. Based on these results, it is concluded that electropolymerization of thiophene played an important role not in the phase transfer kinetics of lithium-ion but in reduction of the electrolyte decomposition at a graphite electrode.     

Discharge occurring at a grounded electrode located in a charged particle cloud

Electrical discharge phenomena from a grounded electrode located in a charged particle cloud have been investigated. Soil conditioning particles charged by corona charging were blown to form a space charge cloud. A grounded sphere electrode was placed at the center of the charged cloud to produce an electrical discharge. A positive pulse discharge extended from the sphere electrode toward the charged cloud with a strong luminescence. A brushlike streamer with a maximum length of 170 mm appeared at an interval of 30 ms. The maximum pulse height of the discharge was 2.4 A. The distribution of the electric field around the sphere electrode was obtained from field analysis using a concentric spherical model. It was found that the magnitude of the discharge depends on the radius of the grounded electrode and the size and charge density of the clouds. © 2001 Scripta Technica, Electr Eng Jpn, 136(4): 7–14, 2001     

Aliphatic Halogenase Enables Late‐Stage C−H Functionalization: Selective Synthesis of a Brominated Fischerindole Alkaloid with Enhanced Antibacterial Activity

The anion promiscuity of a newly discovered standalone aliphatic halogenase WelO5 was probed and enabled the selective synthesis of 13R‐bromo‐12‐epi‐fischerindole U via late‐stage enzymatic functionalization of an unactivated sp³ C?H bond. Pre‐saturating the WelO5 active site with a non‐native bromide anion was found to be critical to the highly selective in vitro transfer of bromine, instead of chlorine, to the target carbon center and also allowed the relative binding affinity of bromide and chloride towards the WelO5 enzyme to be assessed. This study further revealed the critical importance of halogen substitution on modulating the antibiotic activity of fischerindole alkaloids and highlights the promise of WelO5‐type aliphatic halogenases as enzymatic tools to fine‐tune the bioactivity of complex natural products.     

A general-purpose coarse-grained molecular dynamics program

In this article, we describe a general-purpose coarse-grained molecular dynamics program COGNAC (COarse Grained molecular dynamics program by NAgoya Cooperation). COGNAC has been developed for general molecular dynamics simulation, especially for coarse-grained polymer chain models. COGNAC can deal with general molecular models, in which each molecule consists of coarse-grained atomic units connected by chemical bonds. The chemical bonds are specified by bonding potentials for the stretching, bending and twisting of the bonds, each of which are the functions of the position coordinates of the two, three and four atomic units. COGNAC can deal with both isotropic and anisotropic interactions between the non-bonded atomic units. As an example, the Gay-Berne potential is implemented. New potential functions can be added to the list of existing potential functions by users. COGNAC can do simulations for various situations such as under constant temperature, under constant pressure, under shear and elongational deformation, etc. Some new methods are implemented in COGNAC for modeling multiphase structures of polymer blends and block copolymers. A density biased Monte Carlo method and a density biased potential method can generate equilibrium chain configurations from the results of the self-consistent field calculations. Staggered reflective boundary conditions can generate interfacial structures with smaller system size compared with those of periodic boundary conditions.