scholarly journals Light Intensity of a Quartz Mercury Lamp

Nature ◽  
1931 ◽  
Vol 127 (3198) ◽  
pp. 254-254
Keyword(s):  
Light Intensity ◽  
Mercury Lamp ◽  
Quartz Mercury

scholarly journals Phosphorescence of mercury vapour after removal of the exciting light

1913 ◽  
Vol 89 (607) ◽  
pp. 39-44 ◽  
Keyword(s):  
Chemical Reactions ◽  
Present Experiment ◽  
The Other ◽  
Exciting Light ◽  
Mercury Vapour ◽  
Mercury Lamp ◽  
Relative Simplicity ◽  
Quartz Mercury ◽  
Long Time ◽  
Sodium Vapour

By means of Becquerel’s phosphoroscope the fluorescence of solids has been shown to be persistent, but up to the present phosphorescence in the case of liquids and gases has not been observed. That of solids has generally been explained as due to chemical reactions brought about by impurities, while in the case of gases it has been considered that damped vibrations of the rapidity of those connected with light could not be conceived as persisting for a sufficiently long time for the necessary observations to be made. On the other hand, because of their relative simplicity, gases and vapours have been recognised as being eminently suitable for the study of fluorescence and kindred phenomena. Wood has applied the phosphoroscope to the case of sodium vapour, with however a negative result. In the present experiment I have attacked the problem in a different way. The method used was to pass a beam of the exciting light transversely across a rapidly moving column of mercury vapour, obtained by distillation in vacuo . Then if the fluorescence of the vapour persists the luminosity should be carried along with the stream. The fluorescence was excited by 2536 light which was obtained by means of a quartz mercury lamp. Under suitable conditions the vapour could be seen to be still fluorescing, after it had passed a distance of some 18 inches from the point of excitation.

scholarly journals Pulsed-Laser Induced Chain Addition Reaction of Butanal to Diethyl Maleate

1994 ◽  
Vol 15 (1) ◽  
pp. 55-59 ◽  
Author(s):  
R. Stringat ◽  
G. Fabre ◽  
M. Alessandri ◽  
R. Fellous
Keyword(s):  
Quantum Yield ◽  
Light Intensity ◽  
Addition Reaction ◽  
Pulsed Laser ◽  
Diethyl Maleate ◽  
Mercury Lamp ◽  
Chain Mechanism ◽  
Acyl Radical ◽  
Yag Laser ◽  
A Chain

By irradiation of a 5/1 mixture of butanal and diethyl maleate with a pulsed Nd-YAG laser (10 Hz, 13 ns), frequency tripled (λ = 355 nm), diethyl butanoyl succinate is formed by addition. The quantum yield is greater than 1 which means that a chain mechanism occurs which was not the case in previous studies with a mercury lamp. The quantum yield is a function of light intensity and can reach 280 in the range explored (I = 3020 to I = 0.303 KW.cm-2). The excited aldehyde produces the two radicals nPr-ĊHOH and nPr—ĊO. The nucleophilic acyl radical reacts on the diethyl maleate to form an intermediary radical which givs the adduct and a new acyl radical in the presence of an aldehyde molecule. The second radical nPr—ĊHOH captures a hydrogen from the aldehyde producing another acyl radical and butanol.

A SIMPLE LABORATORY QUARTZ MERCURY LAMP

Science ◽  
1927 ◽  
Vol 65 (1677) ◽  
pp. 187-189
Author(s):  
T. Hashimoto ◽  
C. C. Wu
Keyword(s):  
Mercury Lamp ◽  
Quartz Mercury

Fine structure of the retina of the giant scallop, Placopecten magellanicus

1984 ◽  
Vol 42 ◽  
pp. 312-313
Author(s):  
C.V.L. Powell
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Light Intensity ◽  
Scanning Electron Microscope ◽  
Eye Development ◽  
Preliminary Observation ◽  
Columnar Epithelium ◽  
Placopecten Magellanicus ◽  
Environmental Light ◽  
Scanning Electron

The overall fine structure of the eye in Placopecten is similar to that of other scallops. The optic tentacle consists of an outer columnar epithelium which is modified into a pigmented iris and a cornea (Fig. 1). This capsule encloses the cellular lens, retina, reflecting argentea and the pigmented tapetum. The retina is divided into two parts (Fig. 2). The distal retina functions in the detection of movement and the proximal retina monitors environmental light intensity. The purpose of the present study is to describe the ultrastructure of the retina as a preliminary observation on eye development. This is also the first known presentation of scanning electron microscope studies of the eye of the scallop.

Effect of light intensity on the ultrastructure of the filamentous cyanobacterium, Anabaena variabilis

1988 ◽  
Vol 46 ◽  
pp. 300-301
Author(s):  
C. S. Bricker ◽  
S. R. Barnum ◽  
B. Huang ◽  
J. G. Jaworskl
Keyword(s):  
Fatty Acid ◽  
Light Intensity ◽  
Acid Content ◽  
Fatty Acid Content ◽  
Anabaena Variabilis ◽  
Chloroplast Envelope ◽  
Major Constituent ◽  
Filamentous Cyanobacterium ◽  
Photosynthetic Membrane ◽  
Effect Of Light

Cyanobacteria are Gram negative prokaryotes that are capable of oxygenic photosynthesis. Although there are many similarities between eukaryotes and cyanobacteria in electron transfer and phosphorylation during photosynthesis, there are two features of the photosynthetic apparatus in cyanobacteria which distinguishes them from plants. Cyanobacteria contain phycobiliproteins organized in phycobilisomes on the surface of photosynthetic membrane. Another difference is in the organization of the photosynthetic membranes. Instead of stacked thylakolds within a chloroplast envelope membrane, as seen In eukaryotes, IntracytopIasmlc membranes generally are arranged in three to six concentric layers. Environmental factors such as temperature, nutrition and light fluency can significantly affect the physiology and morphology of cells. The effect of light Intensity shifts on the ultrastructure of Internal membrane in Anabaena variabilis grown under controlled environmental conditions was examined. Since a major constituent of cyanobacterial thylakolds are lipids, the fatty acid content also was measured and correlated with uItrastructural changes. The regulation of fatty acid synthesis in cyanobacteria ultimately can be studied if the fatty acid content can be manipulated.

A photoelectron microscope study of surfaces

1989 ◽  
Vol 47 ◽  
pp. 10-11
Author(s):  
W. Engel ◽  
M. Kordesch ◽  
A. M. Bradshaw ◽  
E. Zeitler
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Field Strength ◽  
Uv Light ◽  
Physical Property ◽  
Photon Flux ◽  
Mercury Lamp ◽  
Object Surface ◽  
The Sixties ◽  
Physical Features

Photoelectron microscopy is as old as electron microscopy itself. Electrons liberated from the object surface by photons are utilized to form an image that is a map of the object's emissivity. This physical property is a function of many parameters, some depending on the physical features of the objects and others on the conditions of the instrument rendering the image.The electron-optical situation is tricky, since the lateral resolution increases with the electric field strength at the object's surface. This, in turn, leads to small distances between the electrodes, restricting the photon flux that should be high for the sake of resolution.The electron-optical development came to fruition in the sixties. Figure 1a shows a typical photoelectron image of a polycrystalline tantalum sample irradiated by the UV light of a high-pressure mercury lamp.

Inter-Method Reliability of Pulse Volume Related Measures Derived Using Finger-Photoplethysmography

2018 ◽  
Vol 32 (4) ◽  
pp. 182-190 ◽  
Author(s):  
Kenta Matsumura ◽  
Koichi Shimizu ◽  
Peter Rolfe ◽  
Masanori Kakimoto ◽  
Takehiro Yamakoshi
Keyword(s):  
Light Intensity ◽  
Adverse Effects ◽  
Light Source ◽  
Direct Current ◽  
Resting State ◽  
Current Component ◽  
Psychophysiological Measures ◽  
Pulse Volume ◽  
Optical Paths ◽  
Sensor Positions

Abstract. Pulse volume (PV) and its related measures, such as modified normalized pulse volume (mNPV), direct-current component (DC), and pulse rate (PR), derived from the finger-photoplethysmogram (FPPG), are useful psychophysiological measures. Although considerable uncertainties exist in finger-photoplethysmography, little is known about the extent of the adverse effects on the measures. In this study, we therefore examined the inter-method reliability of each index across sensor positions and light intensities, which are major disturbance factors of FPPG. From the tips of the index fingers of 12 participants in a resting state, three simultaneous FPPGs having overlapping optical paths were recorded, with their light intensity being changed in three steps. The analysis revealed that the minimum values of three coefficients of Cronbach’s α for ln PV, ln mNPV, ln DC, and PR across positions were .948, .850, .922, and 1.000, respectively, and that those across intensities were .774, .985, .485, and .998, respectively. These findings suggest that ln mNPV and PR can be used for psychophysiological studies irrespective of minor differences in sensor attachment positions and light source intensity, whereas and ln DC can also be used for such studies but under the condition of light intensity being fixed.

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