Electromagnetic shielding of HF lamps using wire structures:simulation and measurement

High-frequency (HF) operated lamps, such as HF fluorescent lamps, have several advantages over conventional ones but they contaminate the environment with their EM field emissions. The shielding of the electromagnetic emission should be realized without much effect on the emission of the light. Enclosing the lamps in a housing made of widely spaced thin wires could be an appropriate way to shield the electromagnetic field. The paper studies the effectiveness of some wire structures for shielding the electromagnetic emission from HF fluorescent lamps. An analytical study, method of moments (MoM), and measurements have been carried out to evaluate the strength of the near-field and the shielding effectiveness of the structures     

High microwave and ultra-low noise performance of fullyion-implanted GaAs MESFETs with Au/WSiN T-shaped gate

Fully ion-implanted n⁺ self-aligned GaAs MESFETs with high microwave and ultra-low-noise performance have been fabricated. T-shaped gate structures composed of Au/WSiN are employed to reduce gate resistance effectively. A very thin and high-quality channel with high carrier concentration can be formed by adopting the optimum annealing temperature for the channel, and the channel surface suffers almost no damage by using ECR plasma RIE for gate formation. GaAs MESFETs with a gate length as short as 0.35 μm demonstrated a maximum oscillation frequency of 76 GHz. At an operating frequency of 18 GHz, a minimum noise figure of 0.81 dB with an associated gain of 7.7 dB is obtained. A K_f factor of 1.4 estimated by Fukui's noise figure equation, which is comparable to those of AlGaAs/GaAs HEMTs with the same geometry, reveals that the quality of the channel is very high     

A single-bit-line cross-point cell activation (SCPA) architecturefor ultra-low-power SRAM's

This paper describes a single-bit-line cross-point cell activation (SCPA) architecture, which has been developed to reduce active power consumption and to avoid increase in the size of high-density SRAM chips, such as 16-Mb SRAM's and beyond. A new PMOS precharging boost circuit, introduced to realize the single-bit-line structure, is also discussed. This circuit is suitable for operation under low-voltage power supply conditions. The SCPA architecture with the new word-line boost circuit is demonstrated with the experimental device, which is fabricated by a 0.4-μm CMOS wafer process technology     

Measurement of wavelength variation of mode field radius using far-field pattern method

The far-field pattern measuring technique is used to measure the wavelength dependence of the mode field radius in standard single-mode fibres. Chromatic dispersion calculated from these results is shown to be accurate using as few as three lasers. Both theoretical and experimental results are presented.     

New field measurement system for single-mode fibre dispersion utilising wavelength division multiplexing technique

A new system designed to measure the chromatic dispersion of installed single-mode fibres is presented. This system utilises the modulation phase technique but eliminates the reference laser and fibre. A large dynamic range was demonstrated by the measurement of an 81.1 km length of fibre.     

CD spectra of 5-methyl-2-thiouridine in tRNA-Met-f from an extreme thermophile

5-Methyl-2-thiouridine (S) in tRNA-Met-f from an extreme thermophile is located in the TpsiC region, replacing T, and has a positive CD band centered at 310 nm. Upon heating, the profiles of the change in this band were similar to the UV melting profiles of the change monitored at 260 nm. This strongly suggests a close relation between heat denaturation of the tRNA and the conformation of the S base. Oligonucleotides containing S showed negative CD bands at 320-330 nm, like the monomer S itself, but when the 3'-2/5 fragment containing S formed a complex with the complementary 5'-3/5 fragment, a positive CD band appeared at 310 nm. These results suggest that combination of the TpsiC loop containing S with the hU loop is necessary for the positive band of S at 310 nm. S may serve to strengthen the association of the TpsiC loop with the hU loop in tRNA of the thermophile.     

Renin, cortisol and plasma volume in marine teleost fishes adapted to dilute media

The renin-angiotensin system has been found in teleost fishes from both marine and fresh-water environments. In an attempt to define whether activity of the renin-angiotensin system is related to sodium balance in fishes, we transferred two euryhaline teleosts from seawater to hypo-osmotic media. Plasma renin activity decreased in American eels, Anguilla rostrata, after they were transferred from seawater to fresh water, and it did not change in the aglomerular toadfish, Opsanus tau, after transfer from 50% seawater to 5% seawater. Plasma sodium concentrations decreased significantly in toadfish in 5% seawater and in one group of eels in fresh water. Plasma levels of cortisol, a major mineralocorticoid in teleosts, and plasma volume, measured in eels, remained relatively constant. There are no clear correlations between plasma renin levels and those of plasma sodium or plasma cortisol. These results provide no evidence that the need of these fishes to conserve sodium when in hypo-osmotic media stimulates the renin-angiotensin system.     

Aneurysm of the great vein of Galen--report of a case (author's transl)

A case of aneurysm of the great vein of Galen was reported in which craniotomy and clipping of a feeding artery arising from the left posterior cerebral artery was successfully performed. This 5-month-old girl developed progressive hydrocephalus from 2 months after birth. At 5 months the head circumference was 50 cm with tense enlarged fontanelle. Both eye balls were deviated downward. The deep tendon reflexes were hyperactive with bilateral ankle clonus and positive Babinski's sign. Mild cardiomegaly and hepatomegaly were also noted. Cerebral angiograms showed a large aneurysm of the great vein of Galen fed by a single enlarged arterial branch from the left posterior cerebral artery. After the evaluation of systemic circulatory status and under strict control of fluid transfusion craniotomy was performed. The feeding artery was clipped at its entrance to the aneurysm via left parieto-occipital interhemispheric approach. A rise in the mean arterial blood pressure of 20 mmHg was observed immediately following clipping. The postoperative course was satisfactory except for a left subdural fluid collection which required subduro-peritoneal shunt. The aneurysm was completely disappeared on the postoperative angiograms and the child is regaining the normal development. This is the first case of aneurysm of the great vein of Galen successfully operated in Japan. Clinical symptoms and signs, radiological features and operative treatment of the disease were reviewed from a total of 46 cases reported in the world literature.     

Comparison of coal hydroliquefaction catalysed by ZnCl2-MCln (CuCl,CrCl3 and MoCl5) and ZnCl2 melts

Hydrogenation of four bituminous coals impregnated with 5 wt% of either mixtures of ZnCl₂-MCl_n (CuCl, CrCl₃ and MoCl₅) systems or ZnCl₂ was carried out using a batch autoclave system at 400° for 3 h at 9.8 MPa of initial hydrogen pressure. The ZnCl₂-MoCl₅ system showed the highest yield of the hexane-soluble (HS) fraction compared with the other systems irrespective of the coal used. The difference between the yields of HS fractions using the ZnCl₂-MoCl₅ and other systems was most marked for coals of fairly low volatile matter content, though the conversion was relatively low (47–66%), whilst for coals of high volatile matter content HS yields with the binary melt systems were high (86–91% conversion). Elemental analyses of the HS fractions indicated that the ZnCl₂-MoCl₅ system is most favourable in decreasing the average molecular weight and the heteroatom content of HS, this characteristic trend being confirmed also with five HS fractions separated by Chromatographic techniques. Both elemental analyses and molecular weights of asphaltene (benzene-soluble materials, BS) indicated that the ZnCl₂-MoCl₅ system is also most effective in cracking coal structure.     

Physicochemical characteristics of rapidly dried onion powder and its anti-atherogenic effect on rats fed high-fat diet

Rapidly dried onion (Allium cepa L. cv. Momiji No. 3) powder (OP) prepared from the outer layers (from second to fourth scale leaves from the surface) of onion bulbs was analysed for its quercetin and polyuronide contents, the effects of enzymatic treatment and the anti-atherogenic effect on rats fed a high-fat diet. Quercetin 4′-glucoside (50%), free quercetin (30%) and quercetin 3,4′-diglucoside (20%) were identified as quercetin derivatives, and boiling-water extraction was effective in extracting these compounds. OP contained 12.9% of polyuronides, the basic skeleton of pectin. Enzymatic degradation (cellulase and pectinase, 50 °C for 12 h, pH 6.0) of OP was effective in obtaining a slurry of smaller particle sizes. The free quercetin increased and the glucosides decreased with enzyme treatment. In Wistar rats fed an OP-added high-fat diet, the total cholesterol, HDL-cholesterol and triglyceride concentrations were not significantly different from the rats fed a high-fat diet without OP. However, the atherogenic index (AI) of Wistar rats fed an OP-added high-fat diet was lower (AI = 3.3) than rats fed the diet without OP (AI = 4.1). The incremental elastic modulus (IEM) of the aorta from rats fed the OP-added diet was also significantly lower than that of the rats fed the diet without OP. The AI and IEM values of the rats fed the OP-added diet were quite similar to the values of rats fed the diet without OP but were allowed spontaneous exercise. These results suggest that OP intake is effective for decreasing the risk of arteriosclerosis.