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71.
Hosako I 《Applied optics》2005,44(18):3769-3773
A new method of fabricating multilayer optical coatings used at terahertz frequencies has been developed. Using plasma-enhanced chemical-vapor deposition, a multilayer antireflection coating for germanium optics at terahertz frequencies was fabricated. The coating consists of amorphous silicon and silicon-oxide layers. The transmittance and structure of the coating were experimentally investigated. The transmittance spectrum of the coating on the Ge substrate shows a wideband antireflection behavior in the 40-120 cm(-1) region. 相似文献
72.
The present studies were undertaken to explore further the role of prostaglandins in the release of renin from the renal cortex. To provide the best assessment of renin release, renin was determined by a radioimmunoassay for the direct measurement of renin. Slices of mouse renal cortex were incubated at 37 degrees C with arachidonic acid (AA), 5,8,11,14-eicosatetraenoic acid (ETA), indomethacin, prostaglandins, and synthetic prostaglandin endoperoxide analogue (EPA). Our results showed that AA at 1.5 X 10(-8) M significantly increased renin release at 10 and 30 min of incubation. This renin increase ws abolished by either ETA or indomethacin. Prostaglandin F2 alpha (PGF2 alpha) also significantly stimulated renin release at 10 and 60 min. PGE2 and 16,16-dimethyl PGE2 (DMPGE2) showed much less renin release-stimulating activity. EPA and PGI2 on the other hand very strongly stimulated renin release. However, at higher concentrations the stimulating effect of PGI2 and EPA disappeared and even became inhibitory in the case of EPA. Other prostaglandins were found to have no effect on renin release. The results suggest that the prostaglandin system directly affects renin release from the juxtaglomerular cells independent of systemic neurogenic and hemodynamic influences. 相似文献
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74.
Simple formulas for splice losses have been derived by using the series expansion. The losses are proportional to the square of normalised axial or angular displacement. The coefficient is determined by only the normalised frequency. Normalised frequency dependence measurements of the splice losses show excellent agreement with the theory. 相似文献
75.
Iwao Maki 《Cement and Concrete Research》1979,9(6):757-763
In the system C3A---C4AF---SiO2---MgO, the glass formation region that is closely similar in composition to the interstitial material of portland cement clinker has been determined. The interstitial melt that exists in equilibrium with the silicates at the clinkering temperature contains a little silica. This forms clusters, which increase the viscosity of the melt and cause the latter to supercool appreciably. Crystallization of C3A and C4AF increases the concentration of clusters, which progressively interlock in the residual liquid, thus giving a glass on quenching. The presence of SiO2 in the interstitial melt also enables the metastable formation of the orthorhombic aluminate and the oriented overgrowth of the ferrite on the aluminate to occur through encouraging supercooling of the melt. 相似文献
76.
Very low OH content optical fibres consisting of P2O5-doped silica core and GeO2-P2O5-B2O3-doped silica cladding were fabricated by the m.c.v.d. technique. The relation between the OH absorption loss and the deposition temperature was clarified. The OH content in this fibre could be reduced to about seven parts per billion (~ 7 × 10?9) by using a low deposition temperature. 相似文献
77.
KOBAYASHI Iwao 《材料科学前沿(英文版)》2008,2(3):246
The shell structure of the Bivalvia has been observed with the use of optical and electron microscopes since the early 1900’s. The prismatic structure is one of the more attractive shell structures in bivalved mollusks. This structure is composed of the aggregation of polygonal prisms arranged densely. Each prism is made of small calcite crystallites arranged perpendicular to a growth shell surface. Organic materials, named organic sheaths, accumulate around prisms and stain well with heamatoxylin-eosin.The Bivalvia, which make prismatic structures, are divided into two groups. One group has the inner shell layer made up of a nacreous structure, and the other has the inner shell layer made up of a foliated structure. The aragonite prismatic layer and the prismatic layer are closely related to each other, as is the aragonite prismatic layer to the composite prismatic one. 相似文献
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79.
This paper presents the vibration suppression of a boring bar using piezoelectric actuators installed in the boring bar, and an inductor-resister (LR) circuit, which acts as a mechanical dynamic absorber. The frequency response function of the compliance was designed so that its real part is constrained to suppress regenerative chatter. The designed boring bar with an optimally tuned LR circuit was set on a lathe to evaluate its dynamic characteristic, and it was found that the chatter vibration was successfully suppressed in the cutting test. 相似文献