ABSORPTION STEP-WEAKENERS OF ANTIMONY

1937 ◽  
Vol 15a (9) ◽  
pp. 154-160 ◽  
Author(s):  
G. O. Langstroth ◽  
D. R. McRae
Keyword(s):  
Thermal Decomposition ◽  
High Precision ◽  
Optical Density ◽  
Thin Plates ◽  
Interference Effects ◽  
Made In

It is of advantage to the spectroscopic analyst to have a means of quickly preparing a step-weakener of any required characteristics. A method has been developed in which antimony films are deposited by thermal decomposition of the trihydride. The apparatus required is simple, and a multi-step, weakener may be made in 20 min. The films are nearly neutral below λ 4000Å. Their optical density is quite uniform, and they are sufficiently strong for all practical purposes. For high precision work, the construction of the weakener must be such that undesirable interference effects are avoided. A consideration of the theory of interference phenomena in light transmitted through thin plates suggests several possible methods of construction. Some of these have been adopted and have been found to be satisfactory in practice.

Use of airborne radar imagesat the mapping of steppe fire areas

1995 ◽  
pp. 67-68
Author(s):  
A. K. Monakhov ◽  
M. A. Shubina
Keyword(s):  
Optical Density ◽  
Airborne Radar ◽  
Horizontal Polarization ◽  
Made In

The article proposes the methods of using the radiolocation (RL) images for analysis of picture of steppe fire areas. The images were obtained in the sm wave-diapason with horizontal polarization and resolution in the first tens of meters. By the RL negatives, made in the summer and winter periods, the characteristics of optical density and the contrasts of RL images between fire areas and steppes were determined.

FIB Micromachining and Nano-Structure Fabrication

1999 ◽  
Author(s):  
Raymond A. Lee ◽  
Patrick J. Wolpert
Keyword(s):  
High Precision ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Biological Applications ◽  
Optical Lens ◽  
Nano Structure ◽  
Beam System ◽  
Afm Tips ◽  
Established Technique ◽  
Made In

Abstract FIB Micromachining has long been an established technique, but until recently it has been overshadowed by the more mainstream semiconductor application of the Focused Ion Beam system. Nano- Structure fabrication using the FIB system has become more popular recently due to several factors. The need for sub-micron structures have grown significantly due to a need for enhanced optical and biological applications. Another reason for the growth in micromachining is the improvement made in the ability of FIB systems to produce geometric shapes with high precision. With the latest high-end FIB systems, it is possible to produce microstructures with tens of nano-meters of precision. Optical lens, AFM tips, and nano-apertures are all part of the growing application for FIB Micromachining. This paper will discuss the ability and limitations of the FIB system and some possible application for FIB Micromachining.

scholarly journals High-precision Joining of Small-diameter Shafts to Thin Plates by Rolling Calk.

1995 ◽  
Vol 61 (585) ◽  
pp. 2147-2152
Author(s):  
Takeshi Kawana ◽  
Takashi Ohta ◽  
Takamichi Suzuki ◽  
Yuhji Enomoto ◽  
Yoichiro Tamoto ◽  
...  
Keyword(s):  
High Precision ◽  
Small Diameter ◽  
Thin Plates

Glutamate-like immunoreactivity in the cat superior colliculus and visual cortex: Further evidence that glutamate is the neurotransmitter of the corticocollicular pathway

1997 ◽  
Vol 14 (1) ◽  
pp. 27-37 ◽  
Author(s):  
Chang-Jin Jeon ◽  
Michael K. Hartman ◽  
R. Ranney Mize
Keyword(s):  
Visual Cortex ◽  
Superior Colliculus ◽  
Optical Density ◽  
Retrograde Tracing ◽  
Biochemical Studies ◽  
Deep Layers ◽  
Dense Band ◽  
Cat Superior Colliculus ◽  
Made In ◽  
In Cells

AbstractBiochemical studies provide evidence that the pathway from visual cortex to the superior colliculus (SC) utilizes glutamate as a neurotransmitter. In the present study, we have used immunocytochemistry, visual cortex lesions, and retrograde tracing to show directly by anatomical methods that glutamate or a closely related analog is contained in corticocollicular neurons and terminals. A monoclonal antibody directed against gamma-L-glutamyl-L-glutamate (gamma glu glu) was used to localize glutamate-like immunoreactivity in both the superior colliculus (SC) and visual cortex (VC). Unilateral lesions of areas 17–18 were made in four cats to determine if gamma glu glu labeling was reduced in SC by this lesion. WGA-HRP was injected into the SC of 10 additional cats in order to determine if corticocollicular neurons were also labeled by the gamma glu glu antibody. A distinctive dense band of gamma glu glu immunoreactivity was found within the deep superficial gray and upper optic layers of SC where many corticotectal axons are known to terminate. Both fibers and cells were labeled within the band. Immunoreactivity was also found in cells and fibers throughout the deep layers of SC. Measures of total immunoreactivity (i.e. optical density) in the dense band were made in sections from the SC both ipsilateral to and contralateral to the lesions of areas 17–18. A consistent reduction in optical density was found in both the neuropil and in cells within the dense band of the SC ipsilateral to the lesion. A large percentage of all corticocollicular neurons that were retrogradely labeled by WGA-HRP also contained gamma glu glu. These results provide further evidence that the corticocollicular pathway in mammals is glutamatergic. The results also suggest that visual cortex ablation alters synthesis or storage of glutamate within postsynaptic SC neurons, presumably as a result of partial deafferentation.

Strong Integration in bilingual grammar, formalized

2018 ◽  
Vol 9 (3) ◽  
pp. 427-467 ◽  
Author(s):  
Lisa Hsin ◽  
Geraldine Legendre
Keyword(s):  
Formal Analysis ◽  
Production Data ◽  
Proof Of Concept ◽  
Interference Effects ◽  
English Bilingual ◽  
Wh Questions ◽  
Linguistic Interference ◽  
The Individual ◽  
As Effects ◽  
Made In

Abstract We present elicited production data reflecting cross-linguistic interference effects in the English wh-questions of Spanish-English bilingual children to provide a proof-of-concept for a proposed new formal analysis of such effects across cross-linguistic influence phenomena. The observed interference effects are interpreted as evidence for the Strong Integration hypothesis of bilingual grammatical architecture, in the context of independently documented facilitation and interference effects in a range of bilingual acquisition contexts. Building on an existing Optimality-Theoretic (OT) model of monolingual acquisition and a specific account of the adult grammar of wh-structures across dialects of Spanish, we propose that the individual patterns documented, in particular the sensitivity in child English to distinctions made in Spanish dialects on the basis of an argument/adjunct contrast, find a straightforward explanation in the OT model of acquisition as adapted to bilingual situations. The generalizability of the model as well as effects of exposure and dominance are discussed.

scholarly journals VLF surface-impedance measurements for ice-depth mapping — an assessment of some commonly encountered interference effects

1996 ◽  
Vol 42 (140) ◽  
pp. 33-36 ◽  
Author(s):  
David V. Thiel ◽  
Daniel James ◽  
Peter Johnson
Keyword(s):  
Surface Impedance ◽  
Apparent Resistivity ◽  
Low Frequency ◽  
Two Dimensional ◽  
Interference Effects ◽  
Impedance Measurements ◽  
Very Low Frequency ◽  
Dimensional Boundary ◽  
Lateral Variations ◽  
Made In

AbstractThe effects on very low-frequency surface-impedence measurements of lateral variations commonly found in ice environments have been measured and modelled numerically using die quasi-static two-dimensional boundary-element method. Results indicate that surface-impedance measurements made in the vicinity of crevasses oriented perpendicular to the plane Of incidence, and those made in the vicinity of moraines and melt streams, can all show significant changes to the measured apparent resistivity. It is, therefore, misleading to use such measurements in the interpretation of ice depth.

Graticule Ruling in Australia

1949 ◽  
Vol 160 (1) ◽  
pp. 145-153
Author(s):  
Mansergh Shaw
Keyword(s):  
High Precision ◽  
Etching Process ◽  
The Other ◽  
Geographic Isolation ◽  
Precision Machines ◽  
Glass Blank ◽  
Complete Process ◽  
Better Than ◽  
Made In

The problems of precision manufacture in Australia, arising chiefly from her geographic isolation, are first discussed. The paper then takes one particular problem from the field of optical manufacture and shows how it was solved for the conditions prevailing in the Dominion. The problem discussed is the production of graticules, or reticles, for range-finders, predictors, gun sights, telescopes, binoculars, microscopes, collimators, and many other such instruments. The first part of the paper deals briefly with methods used in reproducing the pattern, particularly the ruling and etching process. The second, and much the larger, part of the paper deals with the design of the high precision machines which were made for ruling the glass disks preparatory to etching the pattern into the glass. Two such machines were developed, one generating the pattern from the movements of the machine itself, the other, a pantograph, by copying the pattern from master plates. A series of self-checking tests is described by which the accuracy of the generating machine could rapidly be tested to an accuracy of much better than 0·0001 inch. A brief survey of the complete process, from glass blank to finished graticule, is made in the Appendix.

Synthesis and characterization of the barium oxalates BaC2O4·0.5H2O, α-BaC2O4 and β-BaC2O4

2002 ◽  
Vol 58 (5) ◽  
pp. 808-814 ◽  
Author(s):  
Axel Nørlund Christensen ◽  
Rita Grønbæk Hazell ◽  
Ian Charles Madsen
Keyword(s):  
Thermal Decomposition ◽  
Ammonium Oxalate ◽  
Barium Chloride ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Weak Hydrogen Bonds ◽  
Made In

The synthesis of BaC2O4·0.5H2O and its thermal decomposition to α-BaC2O4 and β-BaC2O4 was investigated. BaC2O4·0.5H2O is precipitated at room temperature from aqueous solutions of barium chloride and ammonium oxalate. The deuterated compound BaC2O4·0.5D2O was made in analogy with D2O as the solvent. The compounds were characterized by X-ray and neutron diffraction analysis. Single-crystal X-ray diffraction of BaC2O4·0.5H2O measured at 120 K gave the triclinic cell a = 8.692 (1), b = 9.216 (1), c = 6.146 (1) Å, α = 95.094 (3), β = 95.492 (3), γ = 64.500 (3)°, space group P\bar 1, Z = 4. Two independent Ba atoms are each coordinated to nine O atoms at distances from 2.73 (1) to 2.99 (1) Å. One of the two oxalate ions deviates significantly from planarity. The water molecule does form weak hydrogen bonds. In situ X-ray powder diffraction was used to study the thermal decomposition of BaC2O4·0.5H2O and the formation of α-BaC2O4. The X-ray powder pattern of α-BaC2O4 measured at 473 K was indexed on a triclinic cell with a = 5.137 (3), b = 8.764 (6), c = 9.006 (4) Å, α = 83.57 (4), β = 98.68 (5), γ = 99.53 (5)°, and the space group P\bar 1 with Z = 4.

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