Grafting of poly(ethylene oxide) onto C60 fullerene using macroazo initiators

In order to improve the solubility of C₆₀ fullerene in conventional solvents, grafting of hydrophilic poly(ethylene oxide) (PEO) by utilizing the radical-trapping nature of C₆₀ fullerene was investigated. Macroazo initiators containing a poly(ethylene oxide) unit, known as Azo-PEO, were prepared at various molecular weights by the reaction of 4,4′-azobis(4-cyanopentanoyl chloride) with poly(ethylene glycol) methyl ether. PEO radicals formed by thermal decomposition of Azo-PEO were successfully trapped by C₆₀ fullerene to give PEO-grafted C₆₀ fullerene. Their structures were confirmed by FT-IR spectroscopy, size exclusion chromatography, UV-vis spectroscopy, and differential scanning calorimetry. When Azo-PEO with low-molecular weight was reacted with C₆₀ fullerene, a bis-adduct, C₆₀-(PEO)₂, and a tetrakis-adduct, C₆₀-(PEO)₄, were formed. In contrast, in reactions with Azo-PEO of higher molecular weight, only the bis-adduct was formed, and no formation of the tetrakis-adduct was observed. The structure of bis-adduct was found to be 1,4-type. The solubility of C₆₀ fullerene in water, THF, methanol, and other conventional organic solvents was remarkably improved by grafting of PEO. In addition, the thermal stability of PEO was dramatically increased by grafting onto C₆₀ fullerene.     

ARCOR,a new photolithography technique with antireflective coating on resist

The multiple interference effect is one of the major causes of the fluctuation in critical dimension control (CD) and in mark detection for alignment. Suppressing this effect is critical for future photolithography. We propose a new photolithography technique called anti reflective coating on resist (ARCOR), which improves linewidth accuracy and overlay accuracy by suppressing multiple interference. ARCOR consists of relatively simple processes: A clear antireflective film is spun onto the resist prior to the mark detecting for alignment and exposure. The film is subsequently removed and the resist developed in the conventional way. ARCOR differs from ARC, which suppresses the reflection at the resist/substrate interface. ARCOR suppresses the reflection at the air/resist interface. ARCOR allows mark detection and exposure without light intensity-loss and multiple interference. The experiments mainly examine polysiloxane and perfluoroalkylpolyether as ARCOR materials. It is shown that linewidth accuracy can be improved from 0.3 to 0.03 μm. The signal-to-noise ratio of the alignment signal is drastically improved, and the overlay error is about half that of the conventional method. ARCOR is also effective for directly measuring the reflectivity at the resist/substrate interface, which is a key parameter of the multiple interference effect and the halation. Using ARCOR and a thin resist film, the measured ratio of reflected light to incident light indicates the reflectivity at the resist/substrate interface. Because, the probe light does not reflect off the resist surface and the intensity-loss at the resist surface is suppressed. With perfluoroalkylpolyether film, the measurement error is ～ 1.5%.     

Ring-opening polymerization of 2-oxazolines initiated by chloromethyl groups introduced onto carbon black surface

Summary The ring-opening polymerization of 2-oxazolines (OXZs) was found to be initiated by chloromethyl groups introduced onto carbon black surface. The introduction of chloromethyl groups onto the surface was achieved by the reaction of carbon black with 3,3-bischloromethylbenzoyl peroxide in carbon tetrachloride. During the polymerization, poly-OXZs were grafted from carbon black based on the propagation of the polymers from the surface: percentage of grafting increased with an increase of conversion and reached 40–60%. The polymerization was accelerated by the addition of potassium iodide. Poly-OXZ-grafted carbon black produced stable colloidal dispersions in both hydrophobic and hydrophilic solvents.     

Anisotropy in the resistive superconducting transition under magnetic fields in single crystal Pb2Sr2Ho0.5Ca0.5Cu3O8

Anisotropie properties of the single crystal Pb₂Sr₂Ho_0.5Ca_0.5Cu₃O₈ have been investigated by measuring the electrical resistivity in theab-planeρ _ab (H, θ,T), which depends on the angleθ between theab-plane and the magnetic-field direction, in various constant fieldsH perpendicular to the current direction. All the angle-dependent values ofρ _ab (H, θ,T) at a constant temperature are scaled to be on one curve as a function of reduced field. The anisotropic parameter γ≡(m _c ^* /m _ab ^* )^1/2 is estimated as 12–13, which is larger than that of YBa₂Cu₃O₇ and much smaller than that of Bi₂Sr₂CaCu₂O₈. It has been concluded that the anisotropy does not always depend on the thickness of the blocking layer but seems to depend on the overlap of the electronic wave functions along thec-axis. Anisotropy in the pinning potential has also been discussed from the resistive tail in the temperature dependence ofρ _ab (H,θ,T).     

A procedure to analyze surface profiles of the protein molecules visualized by quick-freeze deep-etch replica electron microscopy

Quick-freeze deep-etch replica electron microscopy gives high contrast snapshots of individual protein molecules under physiological conditions in vitro or in situ. The images show delicate internal pattern, possibly reflecting the rotary-shadowed surface profile of the molecule. As a step to build the new system for the "Structural analysis of single molecules", we propose a procedure to quantitatively characterize the structural property of individual molecules; e.g. conformational type and precise view-angle of the molecules, if the crystallographic structure of the target molecule is available. This paper presents a framework to determine the observed face of the protein molecule by analyzing the surface profile of individual molecules visualized in freeze-replica specimens. A comprehensive set of rotary-shadowed views of the protein molecule was artificially generated from the available atomic coordinates using light-rendering software. Exploiting new mathematical morphology-based image filter, characteristic features were extracted from each image and stored as template. Similar features were extracted from the true replica image and the most likely projection angle and the conformation of the observed particle were determined by quantitative comparison with a set of archived images. The performance and the robustness of the procedure were examined with myosin head structure in defined configuration for actual application.     

An agent architecture for strategy-centric adaptive QoS control in flexible videoconference system

In this paper, we propose an agent architecture to improve flexibility of a videoconference system with strategy-centric adaptive QoS (Quality of Service) control mechanism. The proposed architecture realizes more flexibility by changing their QoS control strategies dynamically. To switch the strategies, system considers the properties of problems occurred on QoS and status of problem solving process. This architecture is introduced as a part of knowledge base of agent that deals with cooperation between software module of videoconference systems. We have implemented the mechanism, and our prototype system shows its capability of flexible problem solving against the QoS degradation, along with other possible problems within the given time limitation. Thus we confirmed that the proposed architecture can improve its flexibility of a videoconference system compared to traditional systems. Takuo Suganuma, Dr.Eng.: He is a research associate of Research Institute of Electrical Communication of Tohoku University. He received a Dr.Eng. degree from Chiba Institute of Technology in 1997. His research interests include agent-based computing and design methodology for distributed systems. He is a member of IPSJ, IEICE and IEEE. SungDoke Lee: He is a Ph.D. Student in the Graduate School of Information Sciences in Tohoku University. He received his MEng degree at Chonbuk National University, Korea in 1991. His research interests include Flexible Network and Knowledge of Agent. Tetsuo Kinoshita, Dr.Eng.: He is an associate professor of Research Institute of Electrical Communication of Tohoku University. He received a Dr.Eng. degree in information engineering from Tohoku University, Japan. His research interests include knowledge engineering, cooperative distributed processing and agent-based computing. He received the the IPSJ Best Paper Award in 1997, etc. He is a member of IPSJ, IEICE, JSAI, AAAI, ACM and IEEE. Norio Shiratori, Dr.Eng.: After receiving his Dr.Eng degree at Tohoku University, he joined the Research Institute of Electrical Communication of Tohoku University in 1977, and is now a professor at the same University. He has been engaged in research on distributed processing system, and flexible intelligent network. He received the 25th Anniversary of IPSJ Memorial Prize-Winning Paper Award in 1985, the 6th Telecommunications Advancement Foundation Incorporation Award in 1991, the Best Paper Award of ICOIN-9 in 1994, the IPSJ Best Paper Award in 1997, etc. He has been named a Fellow of the IEEE for his contributions to the field of computer communication networks.     

水力机械模型试验台的设计研究

扼要介绍在水力机械模型试验台建设中,对试验台的主管路系统、流量率定系统、扭矩测量系统等进行的研究。开发了闸板可抽取式强迫压紧特殊阀,杜绝了管路内漏现象的发生;引进了模型水轮机叶片角度联调机构,在保证叶片角度调整精度的同时又提高了工作效率;采取了保持试验水质清洁的相关措施,节约了宝贵的水资源。该试验台通过了由中国电机工程学会和中国水力发电工程学会组织的技术鉴定,达到国际先进水平。     

Fabrication of particle-free thin films by laser ablation combined with an electron beam

Particle-free silicon and nickel thin films were successfully fabricated by laser-ablating a melted section of their target surface, which gives a high evaporation pressure at the melting point. The influence of direct evaporation from a melted target was reduced negligibly by melting the target only locally with a focused electron beam (e-beam) and increasing the laser frequency. The silicon films fabricated by the present method, pulse laser deposition of a partially molten target, were able to firmly adhere to the substrates and withstood steel needle scratching, unlike e-beam-evaporated films.     

A flexible videoconference system based on multiagent framework

We present a design and implementation of a flexible videoconference system (VCS) using multiagent computing technology. The proposed system, we named FVCS, aims to reduce the burden of the users under the operational environment with insufficient computational resources, such as the Internet environment with small-scale computers at homes and offices, by embedding flexibility to the conventional videoconference system. In this paper, we design and implement FVCS with knowledge-based multiagent framework to realize adaptability of FVCS. We also evaluate the adaptability of the prototype systems of FVCS based on an operational situation observed in its experiments. From the result of the experiments, we conclude that the multiagent-based design and implementation is reasonable for construction of FVCS.     

A novel bistable reflective display using quick‐response liquid powder

Abstract— We have developed new powder materials that exhibit liquid behavior, which can lead to the realization of novel bistable and reflective displays having paper‐white appearance, high contrast, and quick response. Two types of display were demonstrated, one had 160 × 160 array of pixels and the other had 320 × 320 in a 3.1‐in.‐diagonal viewable image size corresponding to 66 and 132 dpi, respectively. These displays were driven by passive‐matrix addressing. The displays showed a reflectivity of more than 41%, a contrast more than 1:10, and a pixel response time of less than 0.2 msec. The seven‐segment display for use in clocks was also demonstrated.