Designing cost-efficient inspection schemes for stochastic streamflow environment using an effective Hamiltonian approach

Optimization and Engineering - Designing inspection frequency to efficiently track stochastic dynamics is a fundamental engineering problem. Especially, tracking environmental variables like water...     

Molecular characteristics and gelling properties of carrageenan family 2. Tri-sulfated and tetra-sulfated carrageenans

Summary New series of tri-sulfated (τ-carrageenan) and tetra-sulfated (ρ-carrageenan) carrageenans were prepared by the sulfating reaction from ι-carrageenan. The chain conformations of new carrageenans in aqueous solutions were investigated in the presence of various metal salts by means of static/dynamic light scattering and small-angle X-ray scattering, and their conformational characteristics were discussed with respect to the gelation behaviour. Although the overall conformation of newly prepared carrageenans is specified as a random coil, the local chain retains a rigid-rod-like structure by forming a helical conformation. The sulfate groups on C2 of (1→3)-linked β-D-galactoses were found primarily responsible to prevent gelation. Received: 28 August 2001/Accepted: 17 September 2001     

日本甜菜纸筒育苗移栽的技术改进

日本甜菜纸筒育苗移栽技术由于机械化的发展而不断改进,使生产效率不断提高.日本依靠育苗设施和技术的改进,甜菜育苗期已由原来的30d延长为45～50d;防止苗床幼苗徒长措施主要依靠金属线断根、喷撒植物生长调节剂;机器人分苗和移栽机上的自动选苗装置以及移栽时迅速培土、纸筒周围镇压,使移栽苗与周围土壤密切接触,减少了纸筒内的土壤干燥,提高了移栽苗吸收土壤水分的能力,促进移栽后甜菜苗迅速成活,使育苗移栽甜菜能够高产稳产.     

Production and bond strength of similar-titanium ultrasonic welded joints

The joinability of unalloyed titanium and the bond strength of similar titanium welded joints by ultrasonic welding were investigated. It turned out that sound welded joints of similar titanium were obtained by using the jig for fixing both base metals. In the case of non-fixing and fixing the lower base metal, sound welded joints were not usually obtained due to the slip between the two base metals. Producing welded joints having sufficient bond strength required a certain threshold value of the ultrasonic energy. When the ultrasonic welding was carried out under the condition where the ultrasonic energy was higher than a threshold value (approximately 2000 W s), the welded joints were fractured within the titanium base metal but not at the interface. The values of the bond strength were associated with the fixing method and the surface roughness of the base metals. The bond interface was joined metallurgically for the most part, although some small voids were observed on the bond interface by SEM and EPMA observation.     

Evaluation of a particle trap laser desorption mass spectrometer (PT-LDMS) for the quantification of sulfate aerosols

A particle trap laser desorption mass spectrometer (PT-LDMS) has been developed for the online measurements of the chemical composition of submicron aerosol particles. The PT-LDMS was evaluated by both laboratory and ambient measurements, with the focus being the quantification of sulfate aerosols. Ammonium sulfate ((NH₄)₂SO₄) is generally the predominant form of sulfate aerosols in urban air; hence, it is used as a material for laboratory experiments and calibration. Major fragments of (NH₄)₂SO₄ were observed at mass-to-charge ratios (m/z) of 48 (SO⁺) and 64 (SO₂⁺). The dependence of sensitivity (expressed as the ratio of m/z 48 signal to sulfate mass) on laser power and cell temperature was investigated. An intercomparison of PT-LDMS with a commercial sulfate particle analyzer (SPA) and filter sampling was performed in Tokyo. Good agreement was observed between SPA and filter analysis (slope = 0.98, r² = 0.99). Although the mass concentration of sulfate measured by PT-LDMS exhibited a tight correlation with that measured by SPA, the mass concentration measured by PT-LDMS tended to underestimate that measured by SPA (slope = 0.70, r² = 0.96). While the discrepancy can be mainly attributed to the difference in size cut between PT-LDMS (approximately PM₁) and SPA (PM_2.5), differences in vaporization efficiency were also found to be important.

Copyright © 2016 American Association for Aerosol Research     

A New Route to Perfluoro(Propyl Vinyl Ether) Monomer: Synthesis of Perfluoro(2‐propoxypropionyl) Fluoride from Non‐Fluorinated Compounds

Perfluoro(2‐propoxypropionyl) fluoride ( 1a ), which is the precursor of the perfluorinated propyl vinyl ether (PPVE) monomer of an industrially important perfluoroalkoxy copolymer (PFA), was synthesized by utilizing direct fluorination of the non‐fluorinated counterpart for the first time. The partially‐fluorinated ester 7 synthesized from the desired perfluorinated acid fluoride 1a itself and the non‐fluorinated alcohol 5 , which has a carbon skeleton corresponding to the desired compound 1a , was perfluorinated by liquid‐phase direct fluorination with elemental fluorine. Degradation of the resulting perfluorinated ester 8 gave 2 mols of the desired acid fluoride 1a . In a sense, this process can be called self‐multiplication of a perfluorinated acid fluoride from a non‐fluorinated alcohol.     

Electrochemical etching using surface carboxylated graphite electrodes in ultrapure water

Electrochemical etching enables processing with an atomic-level accuracy, without deteriorating the physical properties of the workpiece; however, contamination of its surface with electrolytes is unavoidable. If it is possible to carry out electrochemical etching without using electrolytes, such a process will be applicable to electronic device manufacturing and precision nanoscale processing of semiconductor materials. In addition, this process does not require the use of chemicals, cleaning after processing or disposal of waste fluid, which results in a low-cost and environmentally friendly process. To develop an electrochemical etching process that does not require the use of electrolytes, we proposed a method in which a functional-group-modified electrode is used as the cathode. A carboxylated graphite electrode was prepared by treating a graphite electrode with sulfuric acid. Electrolysis of ultrapure water was carried out using the obtained electrode as a cathode. The results indicate that the electrolysis current obtained using the modified electrode is approximately six-fold that obtained using an unmodified electrode. Furthermore, we can etch a Cu surface conically in ultrapure water. The current efficiency increases by 70% at maximum, and the minimum current required for electrochemical etching decreases compared with that in the case of using an unmodified electrode.     

Improvement of information filtering by independent components selection

We propose an improvement of an information filtering process with independent components selection. The independent components are obtained by Independent Components Analysis and considered as topics. Selection of independent components is an efficient method of improving the accuracy of the information filtering for the purpose of extraction of similar topics by focusing on their meanings. To achieve this, we select the topics by Maximum Distance Algorithm with Jensen‐Shannon divergence. In addition, document vectors are represented by the selected topics. We create a user profile from transformed data with a relevance feedback. Finally, we sort documents by the user profile and evaluate the accuracy by imputation precision. We carried out an evaluation experiment to confirm the validity of the proposed method considering meanings of components used in this experiment. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 163(2): 49–56, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20519     

Adaptive MLSE Equalizer with Per-Survivor QR Decomposition for Trellis-Coded MIMO Transmission

A trellis-coded multiple-input multiple-output (MIMO) transmission technique, which exploits multiple-antenna elements at both transmitter and receiver sides and employs trellis-coded modulations (TCMs), has potential to significantly increase spectral efficiency in wireless communications. At the receiver, an adaptive equalizer based on maximum-likelihood sequence estimation (MLSE) deals with intersymbol interference (ISI) incurred in wideband transmissions and jointly decodes multiplexed TCM signals. Recently, a sphere-constrained maximum-likelihood detection, so-called sphere decoding, has drawn much attention for reducing the computational burden in MIMO transmission systems. This paper describes the super-trellis structured Viterbi algorithm applying per-survivor sphere decoding, and evaluates the effect of the complexity reduction in branch metric computations. Toshiaki Koike received the B.S. degree in electrical and electronics engineering and M.S. degree in communications and computer engineering from Kyoto University, Kyoto, Japan, in 2002 and 2003, respectively. Since 2003, he has been working towards the Ph.D. degree in communications and computer engineering, Kyoto University. His current research interest includes digital signal processing for multiple-antenna systems and multi-user communications. He has been a Research Fellow of the JSPS since 2004. Hidekazu Murata received B.S., M.S., and Ph.D. degrees in electronic engineering from Kyoto University, Kyoto, Japan, in 1991, 1993, and 2000, respectively. In 1993, he joined the Faculty of Engineering, Kyoto University. Since 2002, he has been an associate professor of Tokyo Institute of Technology, Tokyo, Japan. His current research interests include signal processing and its hardware implementation, with particular application to multihop radio networks. He received the Young Researcher's Award from the IEICE of Japan in 1997 and the Ericsson Young Scientist Award in 2000. He is a member of the IEEE and SITA. Susumu Yoshida received the B.E., M.E. and Ph.D. degrees in electrical engineering from Kyoto University, Kyoto, Japan in 1971, 1973 and 1978, respectively. Since 1973, he has been with the Faculty of Engineering, Kyoto University and currently he is a full professor of the Graduate School of Informatics, Kyoto University. During the last two decades, he has been mainly engaged in the research of wireless personal communications. His current research interest includes wireless transmission technologies beyond IMT-2000 and wireless ad hoc networks. During 1990–1991, he was a visiting scholar at WINLAB, Rutgers University, U.S.A. and Carleton University in Canada. He served as an Executive Committee Chairperson of PIMRC'99, Osaka and also as a Technical Program Committee Chairperson of IEEE VTC 2000-Spring, Tokyo. He was a guest editor of IEEE J-SAC on Wireless Local Communications published in April and May 1996. He was a Director, Journal and Transactions of IEICE during 2002–2004 and has been a Fellow of the IEICE since 2004. He was awarded the Young Researcher's Award in 1978 and the Achievement Award in 1993 both from the IEICE.     

Experimental validation of a linear model for data reduction in chirp-pulse microwave CT

Chirp-pulse microwave computerized tomography (CP-MCT) is an imaging modality developed at the Department of Biocybernetics, University of Niigata (Niigata, Japan), which intends to reduce the microwave-tomography problem to an X-ray-like situation. We have recently shown that data acquisition in CP-MCT can be described in terms of a linear model derived from scattering theory. In this paper, we validate this model by showing that the theoretically computed response function is in good agreement with the one obtained from a regularized multiple deconvolution of three data sets measured with the prototype of CP-MCT. Furthermore, the reliability of the model as far as image restoration in concerned, is tested in the case of space-invariant conditions by considering the reconstruction of simple on-axis cylindrical phantoms.