Photocatalytic Property and Electronic Structure of Lanthanide-based Oxysulfides

Lanthanide-based oxysulfides and sulfide, LnTaO_3.5S_0.5, Ln₁₀OS₁₄ (Ln = La, Pr, Nd, Sm) and La₄In₅S₁₃, were successively synthesized by sulfurization in a flowing H₂S. The sulfurization decreased the band-gap energies from >4 eV to <3eV, because of the formation of occupied S3p orbitals on the top of valence band. In accordance with the small band gap, the H₂ evolution from a 0.01 M Na₂S and 0.01 M Na₂SO₃ solution system was observed under irradiation of light up to >500 nm. The rate of H₂ evolution under light irradiation of >500 nm increased in the order of Ni/LaTaO_3.5S_0.5 < Ru/La₁₀OS₁₄ < Pt/La₄In₅S₁₃.     

Development of a Trans-Mucosal Controlled-Release Device for Systemic Delivery of Antianginal Drugs Pharmacokinetics and Pharmacodynamics

Oral mucosa is well-known to be one of the best routes for drug absorption. But very few R & D works have been initiated to investigate the feasibility of using this site to control drug delivery. A transmucosal controlled-release device, which is capable of achieving excellent absorption and controlled release of drugs, has been developed. The device is a tabletshaped mucoadhesive system which is composed of two layers. The upper layer is a fast-release layer and the lower layer is a sustained-release layer, and designed to be applied between buccal and gingival mucosae. Both layers are formulated from synthetic polymers to control the release of drugs.

Isosorbide dinitrate(ISDN), a well-documented antianginal drug, is known to be susceptible to extensive presystemic elimination when taken orally. It was used as the candidate drug and the systemic bioavailability was studied in human and observed to be improved by as much as 5 fold when compared to a marketed oral sustained-release tablet; On the other hand, much smaller amount of metabolites was formed. The plasma profile of ISDN has also been observed to be substantially prolonged (12 hrs as compared to less than 1 hr for sublingual tablet and spray product on the market). These observations have demonstrated that this device is capable of not only bypassing hepatic “first-pass” metabolism but also having a sustainedrelease property of prolonging the release of ISDN.

Clinical studies performed in the anginal patients for up to one year have demonstrated the therapeutic benefits of this device in achieving a substantial reduction in the frequency of anginal attacks.

This type of device was also applied to the systemic delivery of another antianginal drug, Nifedipine, by employing a formulation with longer sustained drug release property. Again, the clinical results demonstrated that a prolonged duration of therapeutic plasma concentration has also been accomplished.     

Mechanical stress control in a VLSI-fabrication process: a method for obtaining the relation between stress levels and stress-induced failures

An ideal fabrication process is designed to minimize mechanical stress in semiconductor devices and to improve device reliability. Mechanical stress levels were predicted by in-house simulations supported by a thin-film database. These stress levels were correlated with stress-induced defects by TEM analysis supported by fail bit addressing on matured megabit SRAMs. Amorphous-doped silicon film with various annealing temperatures were used for the gate electrode to change the mechanical stress in devices and to get the direct relationship between predicted stress levels and stress related defects. The authors describe brief guidelines for suppressing dislocations in the small geometry shallow-trench isolation process utilizing this system. Polysilicon thickness in the W-polycide gate electrode is designed to minimize mechanical stress in the gate oxide and to suppress the gate oxide failure in probe and class tests. Moreover, critical stress generates dislocations during post source/drain ion implantation anneal obtained by a ball indentation method. This indicated that lower temperature anneal is effective in suppressing the dislocations. A two-step anneal was introduced to suppress dislocations and to enable higher ion activation.     

Using a GPU to Accelerate Die and Mold Fabrication

The authors present a GPU-based method for generating and verifying cutter paths for numerically controlled milling. A CAM system based on this technology is now employed in production at Mazda Motor Corporation for manufacturing stamping dies. This system can compute cutter paths more than 20 times faster than previous methods     

Stochastic system transformation using generalized orthonormal basis functions with applications to continuous-time system identification

This paper studies the system transformation using generalized orthonormal basis functions that include the Laguerre basis as a special case. The transformation of the deterministic systems is studied in the literature, which is called the Hambo transform. The aim of the paper is to develop a transformation theory for stochastic systems. The paper establishes the equivalence of continuous and transformed-discrete-time stochastic systems in terms of solutions. The method is applied to the continuous-time system identification problem. It is shown that using the transformed signals the PO-MOESP subspace identification algorithm yields consistent estimates for system matrices. An example is included to illustrate the efficacy of the proposed identification method, and to make a comparison with the method using the Laguerre filter.     

Effect of annealing conditions on the uniformity of undoped Semi-Insulating InP

Recently, it was found that undoped semi-insulating InP can be obtained by highpressure annealing of high purity materials. The reproducibility and the uniformity was, however, not satisfactory. In the present work, we found that not only Fe concentrations but also Cr and Ni concentrations in annealed wafers were slightly increased during annealing. Since it seems that the origin of the contamination was due to the vapor source of red phosphorus, conductive InP with a trace amount of Fe was annealed under low phosphorus vapor pressure in order to reduce the contamination. By preventing the contamination of Cr and Ni, preparation of semi-insulating InP became highly reproducible. The minimum Fe concentration for realizing semi-insulating InP was found to be 1 x 10¹⁵cm⁻³. It was also found that the better resistivity uniformity can be obtained at higher annealing temperatures.