Modeling of High Pressure Short-Arc Xenon Discharge With a Thoriated Cathode

2021 ◽  
Vol 49 (8) ◽  
pp. 2387-2396
Author(s):  
Nikolai A. Timofeev ◽  
Vladimir S. Sukhomlinov ◽  
Georges Zissis ◽  
Indzhira Yu Mukharaeva ◽  
Dmitrii V. Mikhaylov ◽  
...  
Keyword(s):  
High Pressure ◽  
Short Arc

Advantages of using high-pressure short-arc xenon lamps for display systems

2005 ◽  
Author(s):  
Serdar Yeralan ◽  
Douglas Doughty ◽  
Rudi Blondia ◽  
Rick Hamburger
Keyword(s):  
High Pressure ◽  
Xenon Lamps ◽  
Display Systems ◽  
Short Arc

Research on the Dimming Characteristics of Short Arc Ultra-High Pressure Mercury Lamps for Projection Applications

2013 ◽  
Vol 325-326 ◽  
pp. 413-416
Author(s):  
Shui Jun Shi ◽  
Qiu Yi Han ◽  
Shan Duan Zhang
Keyword(s):  
High Pressure ◽  
Spectral Band ◽  
Luminous Flux ◽  
Power Reduction ◽  
Integrating Sphere ◽  
Ultra High Pressure ◽  
Electric Parameters ◽  
Current Characteristics ◽  
Color Rendering ◽  
Short Arc

The voltage, current and power are measured for short arc ultra-high pressure mercury lamps (UHP) with rating power 250 W driven by 50 Hz square waveform power supply. It is found that the curve slope of voltage-current characteristics is positive in most of the power range, and negative around 170 W. The photometric, colorimetric and electric parameters are measured with an integrating sphere system couple with a spectrometer in UHP dimming experiments. The results show luminous flux increases with power linearly. The luminous efficacy and color rendering index (CRI) reduce with power reduction because of the decrease of spectral continuum. The mercury pressure are calculated with the full width at the half maximum (FWHM) of 546 nm spectral band, which is 6.2-11.0 nm according to the mercury pressure 15.3-25.8 MPa for UHP power 43-258 W.

Influence of Electrode Energy Balance on Gas Convective Pattern of a High-Pressure Xenon Short Arc Lamp

2020 ◽  
Vol 40 (4) ◽  
pp. 819-837 ◽  
Author(s):  
Shiro Maenaka ◽  
Shinichi Tashiro ◽  
Anthony B. Murphy ◽  
Kazunori Fujita ◽  
Manabu Tanaka
Keyword(s):  
High Pressure ◽  
Energy Balance ◽  
Convective Pattern ◽  
Short Arc

Investigation of Short-Arc High-Pressure Xenon Discharge: Effect of Electrode Material Evaporation on Discharge Properties and Pulse Operation

2019 ◽  
Vol 47 (7) ◽  
pp. 3266-3270 ◽  
Author(s):  
Nikolai A. Timofeev ◽  
Vladimir S. Sukhomlinov ◽  
Georges Zissis ◽  
Indjira V. Mukharaeva ◽  
Pascal Dupuis
Keyword(s):  
High Pressure ◽  
Electrode Material ◽  
Pulse Operation ◽  
Short Arc

Characteristics of Radiation of High-Pressure Short-Arc Xenon Gas-Discharge Lamp

2019 ◽  
pp. 50-63
Author(s):  
S.V. Gavrish ◽  
A.N. Kondratyev ◽  
V.V. Loginov ◽  
N.Yu. Petrenko ◽  
S.G. Kireev
Keyword(s):  
High Pressure ◽  
Spatial Distribution ◽  
Quartz Glass ◽  
Cathode Spot ◽  
Spectral Characteristics ◽  
Gas Discharge ◽  
Electrode Erosion ◽  
Discharge Lamp ◽  
Tungsten Layer ◽  
Short Arc

The paper is devoted to the study of changes in characteristics of ultra-high pressure short-arc xenon lamps when a tungsten layer is sprayed onto the quartz shell, as a result of heating and local electrode erosion. The paper analyzes the mechanisms of phenomena occurring in the super-high pressure xenon discharge and the cathode spot, which affect the sputtering of the electrode material. The main negative effects of tungsten deposits appearing on the lamp shell inner surface are considered: a decrease in the optical transparency and mechanical strength of quartz glass, an increase of the bulb temperature, a change in spectral characteristics and spatial distribution of radiation of a gas-discharge lamp. The original method developed for studying the parameters of radiation of a gas-discharge lamp and based on the superposition of the optical axis of the photometer with the axis of the lamp passing through the cathode spot and the considered shell segment, transparent or sprayed, allowed us to compare radiation characteristics of the lamp without changing the plasma parameters. The thermodynamic analysis carried out within the research confirmed the absence of chemical interaction of tungsten layer with quartz glass. Spectral distribution of xenon discharge radiation in the visible and IR ranges is different for a transparent bulb and the bulb with a tungsten spot, which is due to the size of tungsten layer particles on the lamp bulb. A study of spatial distribution of radiation from a gas-discharge lamp showed a decrease in the intensity of radiation in a solid angle bounded by a tungsten spot. At the same time, in this region, there was observed an increase in the temperature of the quartz shell, leading to the appearance of a longitudinal gradient of the temperature field of the gas-discharge lamp.

High-pressure freezing of cells in suspension for low-voltage scanning electron microscopy (LVSEM)

1991 ◽  
Vol 49 ◽  
pp. 64-65
Author(s):  
Marek Malecki ◽  
James Pawley ◽  
Hans Ris
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Low Voltage ◽  
Culture Media ◽  
Cell Structure ◽  
Freeze Substitution ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Cell Culture Media ◽  
Voltage Scanning

The ultrastructure of cells suspended in physiological fluids or cell culture media can only be studied if the living processes are stopped while the cells remain in suspension. Attachment of living cells to carrier surfaces to facilitate further processing for electron microscopy produces a rapid reorganization of cell structure eradicating most traces of the structures present when the cells were in suspension. The structure of cells in suspension can be immobilized by either chemical fixation or, much faster, by rapid freezing (cryo-immobilization). The fixation speed is particularly important in studies of cell surface reorganization over time. High pressure freezing provides conditions where specimens up to 500μm thick can be frozen in milliseconds without ice crystal damage. This volume is sufficient for cells to remain in suspension until frozen. However, special procedures are needed to assure that the unattached cells are not lost during subsequent processing for LVSEM or HVEM using freeze-substitution or freeze drying. We recently developed such a procedure.

Prolonged Fixation Studies For Spaceflight

1973 ◽  
Vol 31 ◽  
pp. 332-333
Author(s):  
Robert Corbett ◽  
Delbert E. Philpott ◽  
Sam Black
Keyword(s):  
High Pressure ◽  
Living Systems ◽  
Prolonged Storage ◽  
Time Intervals ◽  
Early Signs ◽  
Large Numbers

Observation of subtle or early signs of change in spaceflight induced alterations on living systems require precise methods of sampling. In-flight analysis would be preferable but constraints of time, equipment, personnel and cost dictate the necessity for prolonged storage before retrieval. Because of this, various tissues have been stored in fixatives and combinations of fixatives and observed at various time intervals. High pressure and the effect of buffer alone have also been tried.Of the various tissues embedded, muscle, cartilage and liver, liver has been the most extensively studied because it contains large numbers of organelles common to all tissues (Fig. 1).

Cryosectioning plant roots prepared by high-pressure freezing

1987 ◽  
Vol 45 ◽  
pp. 662-663
Author(s):  
R.E. Crang ◽  
M. Mueller ◽  
K. Zierold
Keyword(s):  
High Pressure ◽  
Cell Walls ◽  
Plant Tissues ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Vitreous State ◽  
Radial Depth ◽  
Irregular Topography ◽  
Considerable Depth ◽  
Conventional Freezing

Obtaining frozen-hydrated sections of plant tissues for electron microscopy and microanalysis has been considered difficult, if not impossible, due primarily to the considerable depth of effective freezing in the tissues which would be required. The greatest depth of vitreous freezing is generally considered to be only 15-20 μm in animal specimens. Plant cells are often much larger in diameter and, if several cells are required to be intact, ice crystal damage can be expected to be so severe as to prevent successful cryoultramicrotomy. The very nature of cell walls, intercellular air spaces, irregular topography, and large vacuoles often make it impractical to use immersion, metal-mirror, or jet freezing techniques for botanical material.However, it has been proposed that high-pressure freezing (HPF) may offer an alternative to the more conventional freezing techniques, inasmuch as non-cryoprotected specimens may be frozen in a vitreous, or near-vitreous state, to a radial depth of at least 0.5 mm.

Sign in / Sign up

Export Citation Format

Share Document