On the design of a single-sided linear induction motor for urban transit

Single-sided linear induction motor (SLIM) propulsion and wheel-on-rail support and guidance for urban transit has been developed in Canada and Japan. The maximum speed for urban transit is about 70 km/h, with the trains repeatedly performing powering, coasting, and braking operations within relatively short distances between stations. In the design of SLIM's operating under such conditions, we must take into account energy consumption as well as motor weight, input KVA, and performance characteristics. In this paper, we conduct a theoretical examination of such a SLIM design, estimating its performance characteristics in using space harmonic analysis. Energy consumption is reduced by decreasing the mechanical clearance. The flux density, then, should be a low value of from 0.5 T to 0.6 T. A motor length of from 2 to 2.5 m and pole pitch of about 300 mm are advisable.     

Effect of plasma treatment on thermal stability and magnetic properties of Nd-Fe-B series plastic magnets

In order to improve the thermal oxidative stability of the neodymium series (Nd₂Fe₁₄B) magnetic powder, plasma polymerization of benzene, styrene and acrylonitrile on the powder was carried out and its effect was examined. A strong hydrophobicity was revealed on the surface of the magnetic powder by the plasma treatment, and the thermal oxidative stability and magnetic properties of the powder were remarkably improved. Magnetic properties of the plastic magnets prepared with the magnetic powder coated with plasma polymer of acrylonitrile on the surface, were superior to plastic magnets prepared with untreated powder.     

Quantitative, mechanistic and physiologically realistic approach to the biopharmaceutical design of oral drug delivery systems

The anatomical reserve length for the intestinal absorption of drugs is presented as the framework by which many physicochemical, physiological and dosage form factors are put into quantitative interrelationships. The concept is a basic science approach to the optimization of oral drug formulations and provides a perspective in the selection of strategies and options within established boundaries. The framework, thus far described here, provides the base upon which refinements and other considerations can be added.

What is not covered here are considerations of absorption windows, which we have defined as that part of the small intestine where absorption occurs for special mechanistic reasons. The windows include the pH-absorption window, distribution of aqueous pore pathways along the intestinal tract, specialized membrane transport mechanisms, membrane distribution of enzyme systems and differences in transit times in the intestinal tract. We have omitted this interesting topic from the reserve length treatment since this has been discussed previously¹³. In the course of the theoretical discussions of the reserve length, various gaps in research were highlighted. We leave this to be further discussed by Professor W.I. Higuchi in this symposium book.     

Electromigration in Double-Layer Metallization

The electromigration of the top stripe in aluminum double-layer metallization systems was investigated. The current density dependence and the activation energy characterization are important in double-layer metallization. The step-coverage and coating effects of SiN is better than that of Si02. New phenomena associated with electromigration have been observed as follows: 1. The mean lifetime is affected by the material of the dielectric layer. This material effect might be related to the hardness of layer. 2. The mean lifetime due to electromigration depends on the magnitude and polarity of the electric field applied between adjacent stripes. Ordinary stress tests for electromigratfon are done where current is conducted only in the top stripe and not in the bottom stripe. Our results show that this situation is realistic under conditions existing in microelectronic circuits. The proposed method for stress testing should be used to simulate actual condition in microelectronic circuits. We emphasize that the stress test method used to disclose this electric field effect is important for accelerated stress testing, especially for metallization in VLSI circuits and multi-layer systems. The failure mechanism due to the electric field effect can be explained in terms of the applied electric field deflecting current-carrying electrons in the metal stripe, and is independent of leakage current between stripes.     

Metabolism of 6-mercaptopurine in human leukemic cells

The PRPP concentrations, PRPP formation, and phosphorylation of 6-mercaptopurine in leukocyte suspensions and homogenates prepared from leukemic patients were studied...     

Raised plasma-prolactin levels in essential hypertension: index of reduced hypothalamic dopaminergic activity (author's transl)

Serial measurements of plasma-prolactin concentration (HPr) and plasma-renin activity (PRA) at 30-min intervals were made in 19 male patients with essential hypertension and in 8 normotensive subjects. HPr was markedly higher in the hypertensive patients than in the normotensive controls. Patients with reduced plasma-renin activity and only slightly elevated HPr-levels showed lower urinary sodium excretion, but a more pronouced 24-h natriuretic response to i.v. furosemide than patients with normal renin and very high HPr-levels. Six patients were treated with the dopaminergic agonist bromocriptine. The drug induced a significant blood pressure reduction in five patients and normalised pressure in two patients. The data do not indicate a role for prolactin in sustaining hypertension via renal salt retaining mechanisms. It is suggested that the raised HPr-levels represent an index of altered central nervous function, characterized by reduced hypothalamic activity. The blood pressure-lowering effect of the dopaminergic agonist bromocriptine fits with the hypothesis that reduced hypothalamic dopaminergic activity might be a factor in the pathogenesis of essential hypertension.     

Molecular characterization of the glutathione-dependent formaldehyde dehydrogenase gene FLD1 from the methylotrophic yeast Pichia methanolica

In this paper, we describe molecular characterization of the FLD1 gene, which encodes glutathione-dependent formaldehyde dehydrogenase (FLD), from the methylotrophic yeast Pichia methanolica. The P. methanolica FLD1 gene contains two exons corresponding to a gene product of 380 amino acid residues and a 225 bp intron, respectively, and its deduced amino acid sequence shows high similarity to those of Fld1ps from other methylotrophic yeasts (80-88%). In P. methanolica, FLD activity is mainly induced by methanol, and this induction is not completely repressed by glucose. Moreover, the expression of the PmFLD1 is strictly regulated, mainly at the mRNA level, its expression increasing with increasing methanol concentrations in the medium. These results suggest that FLD1 is involved in the detoxification of formaldehyde in methanol metabolism, and Fld1p coordinates the formaldehyde level in methanol-grown cells according to the methanol concentration on growth.     

HRTEM image contrast and atomistic microstructures of long-period ordered Al-rich TiAl alloys

Long-period superstructures formed in off-stoichiometric L 1(0)-TiAl alloys were investigated by high-resolution transmission electron microscopy (HRTEM). The HRTEM analysis combined with multislice simulation and image processing was carried out to clarify atomistic microstructures of Al5Ti3 and h-Al2Ti ordered states and a short-range ordered (SRO) state in Ti-62.5 at.% Al alloys. Aluminium atoms in the (002) Ti layers form square-, lean rhombus- and fat rhombus-type ordered clusters in the SRO state. The ordered clusters are in contact with each other and form microdomains of various long-period superstructures. The ordered clusters are tiled periodically in a long range to form Al5Ti3 or h-Al2Ti domains and characteristic antiphase boundary structures.