Lamp Intensity Research Articles

Über den Schwellenwert der Pumpenergie von Flüssigkeitslasern im quasistationären Betrieb

Abstract Threshold Pump Intensity of Flash Lamp Pumped Liquid Lasers Laser parameters of flash lamp pumped dye lasers are interpreted on the base of a simplified term scheme. The obtained formular contain the fluorescence characteristics of the liquid solutions.

Modifications to an H2S Tape Sampler for Increasing Sensitivity and Accuracy in H2S Sampling

The tape samplers using lead acetate impregnated paper tapes for continuous hydrogen sulfide sampling are subject to a number of errors which can throw considerable doubt on the accuracy of H2S concentrations being measured. Some of the errors have been minimized with a change in the humidification system and a reduction of the lamp intensity in the optical system.

Photolysis of Formaldehyde at 1470 and 1236 Å

The photolysis of formaldehyde vapor has been examined at 1470 and 1236 Å. Mixed isotope (H2CO+D2CO) and radical scavenger (C2D4) experiments have been utilized in addition to inert gas pressurization and lamp intensity attenuation. The quantum yields for H2 and CO formation are both equal to 2; and both are independent of pressure and lamp intensity at 1470 and 1236 Å. The primary quantum yield for molecular hydrogen elimination (ΦII) was determined from the scavenger results and also from the mixed isotope work. The two values obtained are in reasonably good agreement, viz., ΦII = 0.5. The mechanism most consistent with the experimental observations is as follows: H2CO+hυ→H2+CO, H2CO+hυ→2H+CO, H+H2CO→H2+HCO, 2HCO→H2+2CO, where the quantum yields of primary process (II) and (III) are both equal to 0.5.

Spectral Radiance of the Carbon Arc Between 2500 Å and 1900 Å

The absolute intensity of the carbon arc in the region from 2500 A to 1900 A was measured by comparing it with the intensity of a mercury high-pressure lamp (UV Standard) and a deuterium discharge lamp, both of which had been calibrated before by means of the synchrotron radiation. The intensity of the carbon arc was found to be considerably higher than given in earlier papers. The rms error of the results is less than 10%.

The intensity of electrodeless discharge lamps containing cadmium, mercury, and manganese

There are a number of experimental parameters which have been found to affect the intensity and lifetime of microwave excited electrodeless discharge lamps (EDL's). A full experimental investigation of the effect on EDL intensities of the following parameters is discussed; weight of the material introduced into the lamp; nature of the fill gas; pressure of the fill gas; and applied microwave power. Three model elements were chosen for this study, mercury, cadmium, and manganese (as its bichloride), in order to determine if any general behaviors could be observed. Optimum construction and operation conditions are given for these specific cases. Some general conclusions regarding the mode of operation of EDL's have been drawn. The directly measured EDL intensities are compared to atomic fluorescence measurements in order to describe the relationship between the integrated line intensity and the intensity at the line center.

Photodecomposition of CH2O, CD2O, CHDO, and CH2O-CD2O mixtures at xenon flash lamp intensities

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotodecomposition of CH2O, CD2O, CHDO, and CH2O-CD2O mixtures at xenon flash lamp intensitiesRobert D. McQuigg and Jack G. CalvertCite this: J. Am. Chem. Soc. 1969, 91, 7, 1590–1599Publication Date (Print):March 1, 1969Publication History Published online1 May 2002Published inissue 1 March 1969https://doi.org/10.1021/ja01035a002RIGHTS & PERMISSIONSArticle Views170Altmetric-Citations109LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Gas exchange of algae. IV. Reliability of Chlorella pyrenoidosa.

A single culture of Chlorella pyrenoidosa (700 ml) was grown continuously under uniform environmental conditions for a period of 11 months. During this time, the culture remained uncontaminated and its oxygen production, carbon dioxide consumption, and photosynthetic quotient (PQ = CO(2)/O(2)) were monitored on a 24-hr basis. The gas exchange characteristics of the alga were found to be extremely reliable; the average oxygen production was 1.21 +/- 0.03 ml per min, the carbon dioxide consumption was 1.09 +/- 0.03 ml per min, and the PQ was 0.90 +/- 0.01 when changes in both lamp intensity and instrument accuracy were taken into consideration. Such long-term dependability in the production of oxygen, consumption of carbon dioxide, and maintenance of a uniform PQ warrants the use of C. pyrenoidosa in a regenerative life support system for space travel.

Trap–Trap Triplet Energy Transfer in Isotopic Mixed Benzene Crystals

The phosphorescence and fluorescence spectra of three-component isotopic mixed benzene crystals, containing two different guests in a C6D6 host crystal, are studied as a function of guest concentration, excitation lamp intensity, and temperature. The energy relaxation processes in these systems are discussed, and it is established that few, if any, host-triplet excitons are produced during the interconversion of “trapped” singlet excitation into “trapped” triplet excitation. Triplet–triplet excitation transfer from one guest (trap) to a lower-energy guest (supertrap) is observed at temperatures where the host–guest ΔE is greater than 30KT. The concentration dependence of the trap–supertrap triplet energy transfer is interpreted in terms of a Perrin model and indicates that the energy can be transferred over no more than ∼20 Å in this system. At high lamp intensities, the phosphorescence intensity is found to depend upon the square root of lamp intensity. This is discussed in terms of excitation-annihilation models. Evidence is also presented for the photogeneration of impurities at these high lamp intensities.

Gas Exchange of Algae

A single culture of Chlorella pyrenoidosa (700 ml) was grown continuously under uniform environmental conditions for a period of 11 months. During this time, the culture remained uncontaminated and its oxygen production, carbon dioxide consumption, and photosynthetic quotient (PQ = CO2/O2) were monitored on a 24-hr basis. The gas exchange characteristics of the alga were found to be extremely reliable; the average oxygen production was 1.21 ± 0.03 ml per min, the carbon dioxide consumption was 1.09 ± 0.03 ml per min, and the PQ was 0.90 ± 0.01 when changes in both lamp intensity and instrument accuracy were taken into consideration. Such long-term dependability in the production of oxygen, consumption of carbon dioxide, and maintenance of a uniform PQ warrants the use of C. pyrenoidosa in a regenerative life support system for space travel.

Further Examination of the Reaction of Oxygen Atoms with Perfluoropropene

The reaction of oxygen atoms with C3F6 has been examined further, in both the presence and the absence of molecular oxygen, at room temperature and at 126°. The oxygen atoms were generated from the mercury-sensitized decomposition of N2O. Both (C3F6) and (O2) were varied by a factor of 10 and the lamp intensity by a factor of 200. In addition to N2, the products were CF2O, CF3CFO, C5F10[Complex chemical formula],and, in the presence of O2, C3F6O (perfluoropropylene oxide). The reaction scheme is analogous to that for C2F4 and is discussed in detail. A number of relative rate constants could be estimated, and they are tabulated. Important intermediates are CF2, CF3CF, and C3F6O* in the absence of O2, together with CF2O2 and CF3CFO2 in the presence of O2.

SOME STABLE FLUORESCENT CONVERTER SOLUTIONS ENHANCING OPTICAL PUMPING IN THE VISIBLE REGION

Abstract A series of fluorescent converter solutions is described, increasing the radiation intensity of flash lamps in the region 4000–6000 Å with a factor RΛ1.5˜3. The converter solutions are composed for use at an optical path of 1 cm, are easy to prepare, and are stable under high intensity irradiation with u. v. and visible light.

Generation of Giant Pulses from a Neodymium Laser with an Organic-Dye Saturable Filter

There has been much recent interest in the production of high-peak power laser pulses by regeneration switching. Organic dyes have been used as saturable filters for both the ruby (cyanine dyes) and neodymium (a polymethine dye) to produce single high-power spikes. The cyanine dye, in suitable concentration and path length, can also be used to produce a long train of slightly enhanced (gain about 10) regular Q-switched spikes from the ruby laser, but the neodymium laser can apparently only be operated in the single-pike mode. This paper reports the discovery of saturable filter action in a common dye, rose bengal, a derivative of fluorescein, which permits the production of an extremely regular sequence of enhanced spikes from the neodymium laser. Unlike the previous dyes, the transition corresponding to the saturable absorption occurs between two excited states, not between the ground state and an excited state. The population of the lower excited state is achieved by optical pumping of the dye solution, and, by varying the intensity of the pumping flash lamp, the optical density of the filter may be altered thus changing the spacing between light spikes as well as their height.

Dual Beam Stopped Flow Spectrophotometer Utilizing Modulated Xenon Arcs

This paper describes a dual beam stopped flow apparatus for quantitatively observing rapid (up to 250 sec−1) chemical reactions in turbid suspensions. The unit employs two commercial 150 W xenon arc light sources modulated to produce square light pulses at 5000 cps; two wavelengths of light are selected by monochromators, and the light is delivered to the reaction cuvette of a conventional stopped flow apparatus via a fiber optic light guide ``Y.'' Current and light intensity feedback are utilized to control lamp intensity; simple transistor choppers demodulate the measuring photomultiplier output, and a second photomultiplier is utilized in a differencing scheme to reduce effects of residual lamp instability. The instrument has a limit of detectability of 1×10−3 optical density units; crosstalk of signal from one channel into the other channel is 6% of the change being measured. An example of instrument performance is presented; as now constructed, the instrument provides time resolution at least 5 times higher and reagent economy more than 20 times higher than other available dual wavelength spectrophotometers.

Quantum efficiency of photoconduction in lead oxide

The quantum efficiency of the photoconduction of crystals of red PbO with an aqueous electrode is unity in the wavelength region between 3800 and 3100–3500 Å. This offers a means of calibrating the intensity of mercury lamps emitting at 365/6 mμ.

Enhancement of the Intensity and Stability of Microwave-Operated Vacuum uv Resonance Lamps

Enhancement of the Intensity and Stability of Microwave-Operated Vacuum uv Resonance Lamps

Electronics and Economics in the Handling of Ilfocolor 35mm Colour Negative Film

Conventional photofinishing methods are analyzed to identify (actors governing the speed and economics of handling colour negative films. For 35mm colour negative, a new method of marketing and handling has been devised, leading to a better and cheaper service. Film is sold inclusive of the cost of processing and the provision of a “contact” proof-print strip. Proof-print and negatives are returned directly to the customer. To facilitate safe handling. negotives are returned in 2 X 2 in. card mounts. For the new system, automatic printers have been designed which are more stable. and provide a higher output, than machines previously available. Photocell sensitivities are continuously stabilized and printing lamp intensities are modulated to compensate for differing negative opacities.

Optical Maser Characteristics of Nd3+ in SrMoO4

Stimulated emission was observed at 77 deg K. Lamp intensity variation with time, including fluorescence and stimulated emission and scattered light at 1.0463 mu at 9 and 16% above the threshold energy, was measured. Data are presented in graphical form. (L.N.N.)

暗室ランプの照度測定について

There have been few reports on the measurement of the safe light lamp in a dark room. Therefore, the author made a few experiments to study this measurement. It was concluded that the intensity of the safe lamp in a room 3.3 m in area, was about 11.5 lux. Other experiments with films were conducted to determine the relation of film and developer to fog, and a simple method was worked out to change the intensity of a safety lamp.

Colorimetric Daylight Illuminant with High Ultra-violet Content

For colorimetry of daylight fluorescent materials, a daylight illuminant of higher ultra-violet energy content than that of source C is needed. In an earlier paper it was shown that an increase in ultra-violet energy can be obtained by supplementing source C with another source containing a tungsten lamp and an ultra-violet transmitting filter. Newer data indicate that the ultra-violet content of average daylight may be considerably higher than that assumed in the previous paper. The purpose of this investigation is to see what kind of approximation to this type of ultra-violet energy distribution is possible, using the same arrangement as before. It is shown that an approximation, satisfactory for all cases of daylight fluorescent colorimetry can probably not be obtained with only one supplementary source, using conventional filters and reasonable (tungsten) lamp intensities. A satisfactory solution for the type of ultra-violet distribution involved seems to require at least two supplementary sources. Ex...

Microscope Phase Fluorometer for Determining the Fluorescence Lifetimes of Fluorochromes

A microscope which can measure the mean fluorescence lifetimes of small fluorescent samples is described. Special emphasis is given to fluorochromes dissolved in biological solutions and bound to thin polymeric substances, such as the desoxyribonucleic acid complexes present in the nuclei of cells. Fundamentally, the method is similar to that described by physicists and physicochemists for solutions of fluorochrome only. A diffraction modulator is used to sinusoidally modulate the intensity of a high-pressure mercury-vapor lamp. The phase shift between the unabsorbed exciting light, passing through the microscopic sample, and the fluorescent light is related to the fluorescence lifetime by tanΔφ=ωτ. The phase shift Δφ is obtained differentially from the phase angles φ1 and φ2 of each microscopic light signal with respect to a third less noisy signal, the tracer signal. The principal effort has been directed toward studying the various sources of error in the fluorometer and variabilities in lifetime measurements. The data indicate that the mean fluorescence lifetime (2.7 msec) of proflavine, bound to nuclei of tumor cells and observed with a 130× oil immersion lens, can be determined with a precision of 4×10−10 sec.