Efficient Excitation of Hybrid Modes in a THz Clinotron

Journal of Infrared, Millimeter, and Terahertz Waves - Various regimes of hybrid, bulk-surface, modes being excited in the clinotron oscillator with a sheet electron beam and nonuniform grating...     

Carbon Nanotubes Grown on the Surface of Cathode Deposit by Arc Discharge

Carbon nanotubes prepared by de arc discharge of graphite electrodes in He and CH₄ gas took markedly different morphology. Thick nanotubes embellished with many carbon nanoparticles were obtained by evaporation under high CH₄ gas pressure and high arc current. Thin and long carbon nanotubes were obtained under a CH₄ gas pressure of 50Torr and an arc current of 20A for the anode with a diameter of 6mm.     

A transceiver PIC for bidirectional optical communication fabricated by bandgap energy controlled selective MOVPE

A transceiver PIC consisting of a DFB-LD, a receiver PD and a Y-shaped branch waveguides is realized by in-plane bandgap energy controlled selective MOVPE. Both active and passive core layers are formed in one step selective growth, and complicated fabrication procedure is no longer required. More than 1 mW fiber coupled power and 7 GHz receiver bandwidth are obtained. The modulation and detection operations at 500 Mb/s are successfully demonstrated.     

Application of gene gun for local-regional cancer

We studied the in vivo gene transfusion using a gene gun, formerly used in plants and culture cells. The hand-held type gene gun (Helios Gene Gun System) is simple and convenient for effective gene transfection in living animals. This method has some advantages in that there is no need for use of viral vector, independence on the cell cycle and local inducement of plural genes. There is a great possibility for application to local-regional cancer.     

Use of a YAP1 overexpression cassette conferring specific resistance to cerulenin and cycloheximide as an efficient selectable marker in the yeast Saccharomyces cerevisiae.

Drug-resistance markers for yeast transformation are useful because they can be applied to strains without auxotrophic mutations. However, they are susceptible to technical difficulties, namely lower transformation efficiency and the appearance of drug-resistant mutants without the marker. To avoid these problems, we have constructed a phosphoglycerate kinase (PGK) promoter-driven YAP1 expression cassette, called PGKp-YAP1. Yeast cells containing PGKp-YAP1 were resistant to cycloheximide, a protein synthesis inhibitor, and also to cerulenin, a fatty acid synthesis inhibitor, but not to other drugs tested. The transformation efficiency of PGKp-YAP1 using cerulenin selection was comparable to that using a URA3 auxotrophic marker when low concentrations of cerulenin were used. Non-transformed drug-resistant colonies did appear on the low-concentration cerulenin plates. However, these non-transformed colonies could easily be identified, based on their cycloheximide sensitivity and/or their resistance to aureobasidin A to which the transformants were sensitive. Therefore, the dual drug resistance of PGKp-YAP1 could be used as an effective selection for PGKp-YAP1 recipient cells. The PGKp-YAP1 marker was used to disrupt the LYS2 gene and to transform an industrial yeast strain, indicating that this marker can be used for efficient and reliable gene manipulations in any Saccharomyces cerevisiae strain.     

MITI projects on recycling

MITI has actively done R&D on industrial technology for waste and reclamation and so there are many research items from small scale to large scale. However, Ecofactory and researches on recycling of metallic materials are introduced here. Ecofactory was proposed by the Mechanical Engineering Laboratory and is now at the stage of the Leading Research, a new research scheme in AISt. Researches on recycling of metallic materials are being done with subsidy. Those researches should contribute to both the preservatin of the global environment and effective recycling of waste materials.Abbreviations AIST Agency of Industrial Science and Technology - MITI Ministry of International Trade and Industry - NEDO New Energy and Industrial Technology Development Organization     

R & D Needs - Drying of Ceramics

New research and development needs for the drying of ceramics are prooosed. The researches on the ceramic drying are briefly reviewed and the role of the drying in the ceramic production process iS summarized. The drying must deal with molded materials and the problem is of significant difference from another drying with particulate materials. It means that the drying must be performed with keeping the molded feature and the insufficient completion of drying and the careless operation influence directly on the product quality The importnance of the R & D on the heat and moisture transfer. shrinking mechanism. the deformation behavior and the strain-stress formation in the molded clay issuggested. The subjects are also pointed out for the further improvement of the ceramic drying process and the precise design of molding with high quality.     

Characterization of the cell leakage of a stacked trench capacitor(STT) cell

The cell leakage of a stacked trench capacitor (STT) cell has been investigated. The major leakage mechanisms of the STT are trench-to-trench leakage, trench junction leakage, and LOCOS isolation leakage. It is shown that compared to a conventional trench capacitor, the trench-to-trench leakage current is reduced and high punchthrough voltage is obtained. Therefore, the trench-to-trench spacing can be reduced 0.1 μm shorter than that of the trench capacitor. These reductions result from the STT structure itself. The surface leakage current, which is the dominant leakage current in the trench capacitor, does not flow in the STT. This paper also describes the effect of the sidewall damage caused by trench etching on the trench junction leakage. Reactive ion etching (RIE) produces deep levels just beneath the trench surface. But, the trench junction of the STT is not influenced by these deep levels because the trench surface is covered by a n^-diffused layer. This paper also investigates the relationship between the cell leakage and the retention time. At DRAM operation temperatures, LOCOS isolation leakage is dominant rather than trench junction leakage. Therefore, the deeper trench can increase the storage capacitance and improve the retention time     

An Electronic Approach to Materials Design

A molecular orbital approach to materials design has recently made great progress. This approach is based on the electronic structure calculations by the DV-Xα cluster method. In this paper recent progress in this approachis reviewed. In particular