scholarly journals On selective absorption by luminous mercury vapour

1924 ◽  
Vol 105 (733) ◽  
pp. 520-531 ◽  
Keyword(s):  
Low Pressure ◽  
Systematic Investigation ◽  
The Other ◽  
Resolving Power ◽  
Mercury Vapour ◽  
Selective Absorption ◽  
Central Lines ◽  
Mercury Vapour Lamp ◽  
Main Component ◽  
Green Radiation

In a previous paper published by the authors there were described, among others, experiments on the reversal of the main component of the 5461 A group of lines and its brightest satellite + 0·085 A in the spectrum of the low-pressure mercury vapour lamp. McLennan, Ainslie and Miss Cale have repeated these experiments and, in the main, confirm the results obtained by us. They, however, point out that what is taken as the main component when the green radiation is examined in instruments of resolving power of the order of 200,000 is a group of five lines of wave-lengths - 0·020 A, - 0·008 A, 0, + 0·008 A, and + 0·018 A; and they state that only the three central lines are absorbed by luminous mercury vapour, the unabsorbed satellites + 0·018 A abd - 0·020 A producing the appearance of reversal. They also describe experiments which, they consider, indicated the absence of absorption in the case of all the other components of this group, including +0·085 A. This last result is at variance with our observation of the reversal of this satellite, recorded in the paper cited above. To clear up this point we undertook a systematic investigation of the absorption of the satellites of the three lines 5461 A, 4358 A, and 4047 A (1 p 1 - 1 s , 1 p 2 - 1 s , and 1 p 3 - 1 s on Fowler's notation) the first triplet of the second subordinate series of triplets. We have observed marked absorption, under suitable conditions, in the case of all the satellites of the group 5461 A, excepting one, viz., -0·237 A, and have reversed five of them. We find that even -0·237 A shows feeble, but distinctly perceptible, absorption under exceptionally favourable conditions. In the present paper we describe the behaviour of the luminous vapour in regared to the members of this group (5461 A, 1 p 1 - 1 s ).

scholarly journals Intercalibration of different light-traps and bulbs used in moth monitoring in northern Europe

1998 ◽  
Vol 9 (1) ◽  
pp. 37-51 ◽  
Author(s):  
Reima Leinonen ◽  
Guy Söderman ◽  
Juhani Itämies ◽  
Seppo Rytkönen ◽  
Ilpo Rutanen
Keyword(s):  
The Other ◽  
Northern Europe ◽  
Mercury Vapour ◽  
Light Traps ◽  
Mercury Vapour Lamp ◽  
Species Being ◽  
Tungsten Lamp

Four different combinations of light-traps and bulbs were tested during the summer 1996 in Kainuu, northern Finland: a Jalas model with a 160-W (J/160W) blended light lamp or a 125-W (J/125W) mercury vapour lamp, a Ryrholm trap with a 125-W (R/125W) mercury vapour lamp and a Rothamsted trap with a 200-W tungsten lamp (G/200W). The traps were rotated between four sites every night, but were kept in the same position for the fifth night in order to prevent the possible influence of moonlight. The longest distance between the traps was 150m, and there was no direct visibility between any of them. Three orders were inspected, i.e. Lepidoptera, Coleoptera and Hemiptera, the total numbers of individuals and species being as follows: 20857/425, 862/101 and 1868/58. G/200W collected significantly fewer moths than the other traps. In some cases, J/125W collected significantly more moths and less species than the J/160W design. The R/125W design collected significantly more species than the J/160W design. Similar differences in the effectiveness of the lamps and traps were found in the case of Coleoptera and Hemiptera. Alpha diversities showed the same trend.

scholarly journals Density of the vapour in the mercury arc and the relative intensities of the radiated spectral lines, with special reference to the forbidden line 2270

1927 ◽  
Vol 117 (776) ◽  
pp. 11-29 ◽  
Keyword(s):  
Current Density ◽  
Voltage Drop ◽  
Intensity Variation ◽  
Absolute Intensity ◽  
Spectral Lines ◽  
Mercury Vapour ◽  
Selective Absorption ◽  
Selection Principle ◽  
Absolute Intensities ◽  
Mercury Vapour Lamp

The mercury arc line (1 1 S 0 — 2 3 P 2 ) is ruled out by the selection principle as the transition 2 3 P 2 → 1 1 S 0 involves a change of the inner quantum number by 2. Takamine and Fukuda, however, have detected this line in the end-on radiation from a mercury vapour lamp of “the branched arc” type devised by Dr. Metcalfe and the author for the study of selective absorption in luminous mercury vapour. Foote, Takamine and Chenault have obtained the same result using an arc discharge'in mercury vapour with a hot cathode. Takamine has recently studied the intensity variations of this line with change of current density, using a modified form of “the branched arc.” The interesting fact brought out by the above investigations is that the intensity of the line increases rapidly with current density up to about 0·25 amps, cm. -2 , and then falls off rapidly. In addition, Takamine apparently finds that the intensity variations of the line in question run parallel to those of the band at 2345 attributed to HgH. An increase in the current density in a mercury arc is usually accompanied by an increase in the density of the vapour through which the discharge passes, and one is led to expect a modification in the character of the spectrum by an increase in the concentration of normal atoms resulting from an increase of the density of the vapour, analogous to the effect of a foreign gas like helium or argon on fluorescence in mercury vapour. The present investigation was undertaken with the object of studying (1) the intensity variation of the line 1 1 S 0 — 2 3 P 2 as compared with the intensities of neighbouring lines when, keeping the length of the arc, the current density in it and the voltage drop between the electrodes unaltered, the density of the vapour is varied; (2) the change in its absolute intensity when the current density is altered, the density of the vapour remaining unchanged, and (3) the influence of lowering the density of the vapour on the relative and absolute intensities of the lines belonging to a series in the arc spectrum, other conditions of excitation remaining unaltered.

scholarly journals Effects of ultra-violet radiation upon involuntary muscle, and the supposed physiological interference of visible rays

1926 ◽  
Vol 99 (696) ◽  
pp. 221-229 ◽  
Keyword(s):  
Ultra Violet ◽  
The Other ◽  
Pigment Cells ◽  
Mercury Vapour ◽  
Ultra Violet Radiation ◽  
The Earth ◽  
Involuntary Muscle ◽  
Mercury Vapour Lamp ◽  
Violet Radiation ◽  
Exciting Effect

It was shown by Adler (1) that involuntary muscle is excited and its tone increased by radiation with ultra-violet rays. The excised frog’s stomach, the bladder and the uterus of the rabbit, and that of the guinea-pig, were suspended by him, each in a suitable salt solution, and excited by the mercury vapour lamp. With a glass screen interposed no result was obtained, the visible and longer ultra-violet rays, e. g ., those longer than about 3200 A. U., having no exciting effect. There may be recalled the old observation of Lambert (1760) that the excised iris of fish and frogs reacts to light by contraction; the visible rays in this case act through the pigment which absorbs them (Steinach, Hertel). Contraction of the pigment-free ventral band of the earth-worm can be produced by ultra-violet, but not by visible rays. On the other hand, visible rays excite the pigmented ventral band of Sipunculus nucleus (Hertel, 2). Probably the nerve plexus is excited by the conversion of visible rays into heat in the pigment cells which absorb these rays.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Power Losses in RF Inductor of Ferrite-Free Closed-Loop Inductively-Coupled Low Pressure Mercury Lamps

2020 ◽  
pp. 89-94 ◽  
Author(s):  
Ekaterina V. Lovlya ◽  
Oleg A. Popov
Keyword(s):  
Closed Loop ◽  
Low Pressure ◽  
Mercury Vapour ◽  
Plasma Power ◽  
Power Losses ◽  
Inductive Discharge ◽  
Inductively Coupled ◽  
Radial Inhomogeneity ◽  
Transformer Model ◽  
Rf Inductor

RF inductor power losses of ferrite-free electrode-less low pressure mercury inductively-coupled discharges excited in closed-loop dielectric tube were studied. The modelling was made within the framework of low pressure inductive discharge transformer model for discharge lamps with tubes of 16, 25 and 38 mm inner diam. filled with the mixture of mercury vapour (7.5×10–3 mm Hg) and argon (0.1, 0.3 and 1.0 mm Hg) at RF frequencies of 1, 7; 3.4 and 5.1 MHz and plasma power of (25–500) W. Discharges were excited with the help of the induction coil of 3, 4 and 6 turns placed along the inner perimeter of the closed-loop tube. It was found that the dependence of coil power losses, Pcoil, on the discharge plasma power, Ppl, had the minimum while Pcoil decreased with RF frequency, tube diameter and coil number of turns. The modelling results were found in good qualitative agreement with the experimental data; quantitative discrepancies are believed to be due skin-effect and RF electric field radial inhomogeneity that were not included in discharge modelling.

Enhancing the Accuracy of Peak Hourly Demand in Bike-Sharing Systems using a Graph Convolutional Network with Public Transit Usage Data

2021 ◽  
pp. 036119812110120
Author(s):  
Jung-Hoon Cho ◽  
Seung Woo Ham ◽  
Dong-Kyu Kim
Keyword(s):  
Adjacency Matrix ◽  
Public Transit ◽  
Demand Forecasting ◽  
The Other ◽  
Convolutional Network ◽  
Demand Pattern ◽  
Temporal Features ◽  
Unmet Demand ◽  
Bike Sharing ◽  
Main Component

With the growth of the bike-sharing system, the problem of demand forecasting has become important to the bike-sharing system. This study aims to develop a novel prediction model that enhances the accuracy of the peak hourly demand. A spatiotemporal graph convolutional network (STGCN) is constructed to consider both the spatial and temporal features. One of the model’s essential steps is determining the main component of the adjacency matrix and the node feature matrix. To achieve this, 131 days of data from the bike-sharing system in Seoul are used and experiments conducted on the models with various adjacency matrices and node feature matrices, including public transit usage. The results indicate that the STGCN models reflecting the previous demand pattern to the adjacency matrix show outstanding performance in predicting demand compared with the other models. The results also show that the model that includes bus boarding and alighting records is more accurate than the model that contains subway records, inferring that buses have a greater connection to bike-sharing than the subway. The proposed STGCN with public transit data contributes to the alleviation of unmet demand by enhancing the accuracy in predicting peak demand.

Photorearrangement of 2-cyanobicyclo[2.2.1]hept-2-ene. Observation of 1,2- and 1,3-sigmatropic shifts

1982 ◽  
Vol 60 (13) ◽  
pp. 1657-1663 ◽  
Author(s):  
Ikbal A. Akhtar ◽  
John J. McCullough ◽  
Susan Vaitekunas ◽  
Romolo Faggiani ◽  
Colin J. L. Lock
Keyword(s):  
Single Crystals ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Major Product ◽  
Molecular Structures ◽  
Lithium Aluminum ◽  
Mercury Vapour ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Mercury Vapour Lamp

Irradiation of 2-cyanobicyclo[2.2.1]hept-2-ene (2-cyanonorbornene, 4) in hexane, with the full arc of a mercury vapour lamp, gives the rearrangement products 1-cyanobicyclo[4.1.0]hept-2-ene 5 and 7-cyanotricyclo[4.1.0.03.7]heptane 6 in the ratio 20:1. These products were separated by preparative vpc. The structure of the major product 5 was determined by single crystal X-ray analysis. Reduction of 5 with lithium aluminum hydride gave the corresponding primary amine, which was converted to the p-bromobenzenesulfonamide 9, mp 150–151 °C, which gave single crystals from ethanol–water. The crystal and molecular structures are described. The minor product 6 was hydrogenated to give 7-cyanobicyclo[2.2. 1]heptane. Formation of 5 and 6 may involve concerted σ2s + π2s and σ2a + π2a processes respectively, which are photochemically allowed.

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