Organometallic Bonding in an Ullmann‐Type On‐Surface Chemical Reaction Studied by High‐Resolution Atomic Force Microscopy

The on‐surface Ullmann‐type chemical reaction synthesizes polymers by linking carbons of adjacent molecules on solid surfaces. Although an organometallic compound is recently identified as the reaction intermediate, little is known about the detailed structure of the bonded organometallic species and its influence on the molecule and the reaction. Herein atomic force microscopy at low temperature is used to study the reaction with 3,9‐diiododinaphtho[2,3‐b:2′,3′‐d]thiophene (I‐DNT‐VW), which is polymerized on Ag(111) in vacuum. Thermally sublimated I‐DNT‐VW picks up a Ag surface atom, forming a C? Ag bond at one end after removing an iodine. The C? Ag bond is usually short‐lived, and a C? Ag? C organometallic bond immediately forms with an adjacent molecule. The existence of the bonded Ag atoms strongly affects the bending angle and adsorption height of the molecular unit. Density functional theory calculations reveal the bending mechanism, which reveals that charge from the terminus of the molecule is transferred via the Ag atom into the organometallic bond and strengths the local adsorption to the substrate. Such deformations vanish when the Ag atoms are removed by annealing and C? C bonds are established.     

Interphase transfer of tackifier between poly(butadiene) and poly(styrene-co-butadiene)

The interphase transfer behavior of poly(styrene-co-α-methyl styrene), which is known as a tackifier in rubber industry, is investigated using poly(butadiene) rubber (BR) and poly(styrene-co-butadiene) rubber (SBR). The films of pure rubbers and the blends with the tackifier were prepared by a solution-cast method using toluene as a solvent. Two sheets composed of different rubbers, in which the tackifier was mixed at least in one rubber sheet, were piled together and annealed beyond the glass transition temperature T _g of the tackifier. The transfer phenomenon of the tackifier between the sheets was evaluated by the peak shift in the tensile loss modulus E″ curve, ascribed to T _g of the rubbers, which was measured by the dynamic mechanical analysis. Moreover, crystallization temperature of BR was also employed as a measure of the transfer, because the tackifier retards the crystallization of BR. It is found that the tackifier moves from one rubber to another during annealing procedure to reduce severe localization. When the content is the same in each rubber, the tackifier immigrates from BR to SBR, suggesting a better miscibility with SBR. This behavior is attributed to the small difference in the solubility parameter between SBR and the tackifier as compared to that between BR and the tackifier.     

1千伏以下的金属球间隙静电放电辐射特性的测量研究

In this study, the characteristics of Electromagnetic (EM) radiation caused by Electrostatic Discharges (ESDs) from metal spheres charged to voltages less than 1 kV are examined experimentally. Our experimental system consists of a pair of spherical elec-trodes of different diameters, a 1-18 GHz-band- width horn antenna and a 20-GHz-bandwidth digitizing oscilloscope. Polarization, waveform duration and peaks of antenna-received voltages from the EM field radiation are measured in order to clarify the EM radiation mechanism. The ratio of the received voltages between the antenna arr-angements of the field polarization parallel and perpendicular to the spark pass is 18 to 20 dB. The polarities of the antenna-received voltages are the same as those of the charge voltages across the gap. Moreover, the waveform duration and the first peaks increase with an increase in the diameters of the spherical electrodes. Consequently, we find that the polarization, waveform duration and first peaks of the EM field radiation can be explained by a dipole antenna structure, which makes the spark part of the spherical electrodes a feeding point on the straight line passing through the centres of the two spheres.     

Fullerene Production in Tons and More: From Science to Industry

In the last decade, application of fullerenes has been proposed actively in a wide range of areas, and recent developments suggest that many of those applications are to be practical technologies. However, there has been no large-scale production enterprise for commercial usage of fullerenes. High production cost and limited availability of fullerenes have been the main obstacle in the development of the Fullerene Market. Improved flame-based technology leads to the most feasible process for mass production of fullerenes, since it is a continuous process and uses inexpensive hydrocarbons as its starting materials. In May 2003, we started fullerene production in tons and more to supply fullerenes with reasonable price as practical materials for industries.     

950 keV, 3.95 MeV and 6 MeV X-band linacs for nondestructive evaluation and medicine

We are developing compact X-band linac X-ray sources for nondestructive evaluation and medicine. First, we develop a portable X-ray system by a 950 keV 9.4 GHz X-band linac to realize on-site inspection. We use a low power (250 kW) magnetron as an RF source for compactness of the whole system. Since the RF power source is quite small and the stored energy in the structure is also small, we faced the problem of beam loading and current/RF-power oscillation. We are analyzing the problem by the circuit model. We plan to use this system for erosion inspection of metal pipes of petrochemical complex. By adopting a side-coupling cavity design to avoid the oscillation, we have developed 6 MeV X-band (9.3 GHz) linac for pinpoint dynamic tracking cancer therapy. Furthermore, we are manufacturing 3.95 MeV X-band (9.3 GHz) linac X-ray source with flexible waveguides for on-site bridge inspection. Updated results and situations are presented.     

Vibration analysis of cubic rotary-linear piezoelectric actuator

Cubic design of a stator in a rotary-linear piezoelectric actuator is sophisticated and interesting, but the vibration theory of the cubic stator remains unclear when using the finite element method (FEM). In this paper, we analyze the vibration behavior of the cubic stator by applying the energy method, which distinguishes the component of mechanical energy. By changing the design of the stator (especially the length in the direction of the through-hole axis), we clarify how the vibration modes are in accordance at one equal frequency in cubic shape. The behavior of the vibration modes is discussed using conventional vibration theory of a beam and a plate.     

Linked‐BINOL: An Approach towards Practical Asymmetric Multifunctional Catalysis

The development and application of a novel linked‐1,1′‐binaphthol (linked‐BINOL) as an approach towards practical asymmetric multifunctional catalysis is described. Linked‐BINOL was first designed to increase the stability of a Ga‐Li‐BINOL complex against ligand exchange with 4‐methoxyphenol. An oxygen‐containing linked‐BINOL, which is a semi crown ether, was effective in both promoting the formation of a monomer complex and increasing the stability of the Ga‐Li complex. A Ga‐Li‐linked‐BINOL complex promoted the epoxide opening reaction in up to 96% enantiomeric excess (ee). Second, based on the X‐ray structural information of the Ga‐Li‐linked‐BINOL complex, we designed a more stable lanthanide linked‐BINOL complex. An air‐stable, storable, and reusable La‐linked‐BINOL complex promoted the Michael reaction in up to >99% ee. The catalyst activity remained unchanged after storage under air for 4 weeks. Calculations suggested that the linked‐BINOL would function as a pentadentate ligand in a lanthanum complex, thus efficiently improving the stability of the complex. Finally, the linked‐BINOL was applied to a new homobimetallic multifunctional catalysis. A dinuclear Zn‐Zn‐linked‐BINOL complex promoted the enantio‐ and diastereoselective direct aldol reaction in up to 99% ee, where one Zn cation might function as a Lewis acid and the other Zn‐phenoxide as a Brønsted base.     

Controlled nanoporous structures of a marine diatom

We demonstrated chemical etching of a marine diatom shell with 1 N NaOH for controlling the pore size of nanoporous structures of the shell under various conditions. Scanning electron microscopy (SEM) images clearly revealed that the pore size of the diatom shells was regulated in the case of etching at 25 degrees C. In contrast, fluctuations in the etched structures was relatively high even during short periods degradation at 40, 60, and 90 degrees C; therefore, controlled nanoporous structures could not be fabricated. This is the first example of artificial modification of natural diatom shells at the nanoscale although diatom shells have been widely used in industry. In addition, a backbone-like structure was observed during the etching process. The structure was similar to the intermediate structure observed during the primitive stage of the diatom cell growth. Probably, this information is valuable for studying the mechanism of nanoporous structures of diatoms.     

Surface‐discharge electrode design methods for ACPDPs

Abstract— In order to lower development costs and to shorten development time, small panels, under 10‐in on the diagonal, are used for the experiments to improve the luminous efficiency of plasma‐display panels. However, it is difficult to show the same results as those of large panels, over 40 in. on the diagonal. In this paper, first, we show that the luminous efficiency and the voltage margin of mini‐panels are not obtained with large panels by using an actual 46‐in. PDP. The reason is that the resistance in the large panels is larger than that in the mini panels and the voltage drop in the large panels are larger than in mini‐panels. Therefore, we conclude that the bus electrode width and the transparent electrode width are important factors in the design of large PDPs. Next, we show the technique of designing large panels by using a database obtained from mini‐panels. The estimated cell‐design results show good agreement with an actual 46‐in. PDP in luminous efficiency and minimum sustain voltage. We show that a desired large PDP can be obtained by using the cell design proposed in the present paper.