Microwave absorption in compressed CO sub 2.
Microwave absorption in compressed carbon dioxide between 150 and 300 gc measured, detecting no losses at 150 gc
MOLECULAR ABSORPTION↗
SEARCH · Engineering Papers
Results for “molecular spectrum”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Excitation rates in the auroral nitrogen second positive group.
Auroral excitation rates and molecular vibrational tempratures in nitrogen 2PG from Franck-Condon factors obtained from intensity measurements and high resolution absorption spectral data
ELECTRON TRANSITION↗
Intensity measurements in the laboratory on the O sub 2 Herzberg I
Intensity measurements on molecular oxygen Herzberg I system emitting in afterglow of microwave discharge, noting dependence of transition moment on internuclear distance
TRANSITION POINT↗
Charge transfer between He super plus and N sub 2.
Emission occurring when mixing molecular nitrogen with helium ion following charge transfer analyzed spectroscopically
HELIUM↗
Rotational spectrum of ethylene episulfoxide.
Rotational spectrum of ethylene episulfoxide to determine molecular structure, particularly orientation of C sub 2 S ring
White, W. F.↗
Biomedical experiments. Part A: Biostack experiment
The biostack experiment is described which was designed to study the biologic effects of individual heavy nuclei of galactic cosmic radiation during space flight outside the magnetosphere of the earth. Specifically, the biostack experiment was designed to promote research on the effects of high energy/high Z particles of galactic cosmic radiation on a broad spectrum of biologic systems, from the molecular to the highly organized and developed forms of life. The experiment was considered unique and scientifically meritorious because of its potential yield of information - currently unavailable on earth - on the interaction of biologic systems with the heavy particles of galactic cosmic radiation.
Buecker, H.↗
Strong far-infrared emission from a compact source in sharpless 140
High-spatial-resolution observations of S140 are presented at wavelengths from 35 to 175 microns. A single strong far-infrared source has been found coincident with a compact near-infrared and H2O maser source and the center of a molecular cloud. The far-infrared spectrum suggests either significant absorption in the 20-micron region or a two-temperature dust structure. The infrared luminosity of approximately 20,000 suns is comparable to that of a late O or early B star, although no radio continuum flux has been seen from this object. The source is quite likely a dust-embedded protostar.
Harvey, P. M.↗
The ultraviolet spectra of three N-type carbon stars
The paper reports the successful detection of the ultraviolet spectra of three N-type carbon stars: BL Ori, TX Psc, and T Ind. Exposures of approximately 2-3 hours with the LWR camera of the IUE Satellite at low dispersion were necessary to record the ultraviolet flux. The shortward extension of the photospheric continuum is well exposed down to about 2800 A, with strong molecular and atomic absorption features. The spectrum appears not to be seriously affected by the unknown opacity source which blankets N stars (especially redder ones) in the violet. Emission lines of Mg II (h and k) and C II (2325 A) are conspicuous, indicating the presence of chromospheres in the stars. The ratios of integrated fluxes in the Mg II lines and C II lines to bolometric flux are respectively much smaller and slightly smaller than values observed in oxygen-rich M giants and supergiants.
Johnson, H. R.↗
Cosmological gamma-ray burst model
A cosmological gamma-ray burst model that reproduces the observed gamma-ray spectra was developed. This model, which is an outgrowth of work on synchrotron emission from cosmological sources, creates the observed spectra from a power law spectrum through Compton attenuation in dense molecular clouds. It restricts the burst source to the centers of galaxies, and it is easily tested through comparisons with time dependent burst spectra. Dr. Brainerd continued development of a Monte Carlo code that tracks the random walk of a gamma-ray through a plasma in a strong magnetic field and used this code to show that a two temperature plasma in a strong magnetic field can suppress soft x-ray emission.
Brainerd, J. J.↗
Condensation and vaporization studies of CH3OH and NH3 ices: Major implications for astrochemistry
In an extension of previously reported work on ices containing H2O, CO, CO2, SO2, H2S, and H2, we present measurements of the physical and infrared spectral properties of ices containing CH3OH and NH3. The condensation and sublimation behavior of these ice systems is discussed and surface binding energies are presented for all of these molecules. The surface binding energies can be used to calculate the residence times of the molecules on grain surfaces as a function of temperature. It is demonstrated that many of the molecules used to generate radio maps of and probe conditions in dense clouds, for example CO and NH3, will be significantly depleted from the gas phase by condensation onto dust grains. Attempts to derive total column densities solely from radio maps that do not take condensation effects into account may vastly underestimate the true column densities of any given species. Simple CO condensation onto and vaporization off of grains appears to be capable of explaining the observed depletion of gas phase CO in cold, dense molecular cores. This is not the case for NH3, however, where thermal considerations alone predict that all of the NH3 should be condensed onto grains. The fact that some gas phase NH3 is observed indicates that additional desorption processes must be involved. The surface binding energies of CH3OH, in conjunction with this molecule's observed behavior during warm up in H2O-rich ices, is shown to provide an explanation of the large excess of CH3OH seen in many warm, dense molecular cores. The near-infrared spectrum and associated integrated band strengths of CH3OH-containing ice are given, as are middle infrared absorption band strengths for both CH3OH and NH3.
Sandford, Scott A.↗
Condensation and Vaporization Studies of CH3OH and NH3 Ices: Major Implications for Astrochemistry
In an extension of previously reported work on ices containing H20, CO, CO2, SO2, H2S, and H2, We present measurements of the physical and infrared spectral properties of ices containing CH30H and NH3.The condensation and sublimation behavior of these ice systems is discussed and surface binding energies are presented for all of these molecules. The surface binding energies can be used to calculate the residence times of the molecules on grain surfaces as a function of temperature. It is demonstrated that many of the molecules used to generate radio maps of and probe conditions in dense clouds, for example CO and NH3, will be significantly depleted from the gas phase by condensation onto dust grains. Attempts to derive total column densities solely from radio maps that do not take condensation effects into account may vastly underestimate the true column densities of any given species. Simple CO condensation onto and vaporization off of grains appears to be capable of explaining the observed 87 of gas phase CO in cold, dense molecular cores. This is not the case for NH3, however, where thermal considerations alone predict that all of the NH3 should be condensed onto grains. The fact that some gas phase NH3 is observed indicates that additional desorption processes must be involved. The surface binding energies of CH3OH, in conjunction with this molecule's observed behavior during warm up in H2O-rich ices, is shown to provide an explanation of the large excess of CH3OH seen in many warm, dense molecular cores. The near-infrared spectrum and associated integrated band strengths of CH3OH-containing ice are given, as are middle infrared absorption band strengths for both CH3OH and NH3.
Sandford, Scott A.↗
Outgassing of Flown and Unflown MIR Solar Cells
A solar panel array with more than ten years space exposure was removed from the Mir core module in November 1997, and an eight panel section was returned to Earth in January 1998. Several solar cells were removed from panel eight of the returned array and placed in a high vacuum system with a residual gas analyzer (200 amu mass spectrometer) and a cold finger. Similar unflown solar cells of the same vintage were later obtained from Energia. Several of the unflown cells were also placed in the vacuum system and outgassed residues were collected on the LN2 cold finger. Almost 3 mg of outgassed residue was collected -from a string of three unflown solar cells over a period of 94 hours under vacuum. The collected residue was weighed with a microbalance, and then the residue was analyzed by FTIR spectroscopy, and by gas chromatograph-mass spectroscopy. About 25 outgassed constituents were separated by the gas chromatograph, and a high-resolution mass spectrum was obtained of each constituent. Molecular identifications have been made for the constituents. The constituents are primarily cyclic siloxanes, and several of the constituents are isomers of the same molecule. Most of the outgassed constituents have a molecular mass of about 500 amu. Almost one mg of residue was extracted from one sq cm of coverglass/adhesive from a flown solar cell by soaking in isopropyl alcohol for 30 minutes. The gas chromatograph separated about 20 constituents. The constituents are mostly cyclic siloxanes with linear branches, hydrocarbons, and phthalates. The typical molecular mass is about 600 amu. These identifications of specific outgassing molecules have resulted in a more complete understanding of the SiO(x) contamination on the Mir solar cell coverglasses, and on the MEEP experiment trays and optical specimens during the Shuttle-Mir Phase One flight experiment program. Adjusted outgassing rates based on the data reported here, and/or measured outgassing rates and specific molecular identifications of ISS hardware samples are needed to input into model predictions of induced environment effects of the ISS.
Harvey, Gale A.↗
Plasma-enhanced chemical vapor deposition of multiwalled carbon nanofibers
Plasma-enhanced chemical vapor deposition is used to grow vertically aligned multiwalled carbon nanofibers (MWNFs). The graphite basal planes in these nanofibers are not parallel as in nanotubes; instead they exhibit a small angle resembling a stacked cone arrangement. A parametric study with varying process parameters such as growth temperature, feedstock composition, and substrate power has been conducted, and these parameters are found to influence the growth rate, diameter, and morphology. The well-aligned MWNFs are suitable for fabricating electrode systems in sensor and device development.
Nanotechnology/instrumentation/methods↗
A priori predictions of the rotational constants for HC13N, HC15N, C5O
Ab initio molecular orbital theory is used to estimate the rotational constant for several carbon-chain molecules that are candidates for discovery in interstellar space. These estimated rotational constants can be used in laboratory or astronomical searches for the molecules. The rotational constant for HC13N is estimated to be 0.1073 +/- 0.0002 GHz and its dipole moment 5.4 D. The rotational constant for HC15N is estimated to be 0.0724 GHz, with a somewhat larger uncertainty. The rotational constant of C5O is estimated to be 1.360 +/- 2% GHz and its dipole moment 4.4. D.
NASA Discipline Exobiology↗
A convenient synthesis of a novel nucleoside analogue: 4-(alpha-diformyl-methyl)-1-(beta-D-ribofuranosyl)-2-pyrimidinone
The nucleoside analogue 4-(alpha-diformyl-methyl)-1-(beta-D-ribofuranosyl)-2-pyrimidinone (5) was prepared from the corresponding 4-methyl pyrimidinone nucleoside by means of the Vilsmeier reaction. The unprotected nucleoside can be phosphorylated directly with phosphorus oxychloride in triethyl phosphate.
Non-NASA Center↗
Delta excitations and shell-model information in heavy-ion, charge-exchange reactions
We calculate total cross sections for coherent pion production using localized plane-wave approximations for the shell-structure of valence nucleons that are excited to delta particles in the intermediate state in the (12C, 12B) and (12C, 12N) charge-exchange, heavy-ion reactions. We find comparable agreement to projectile downshift data for 12C(12C, 12B)12N. Then we improve the formalism by replacing the localized plane wave bound states with harmonic oscillator states which are imbedded in a multipole expansion approach and calculate pion differential cross sections to test for the sensitivity of the spectra to the single-particle mass parameter.
NASA Program Space Medicine↗
Age-dependent loss of the C-terminal amino acid from alpha crystallin
Antiserum made against the C-terminal region of alpha-A crystallin was used to monitor the purification of a tryptic peptide containing the C-terminus of the molecule from fetal versus adult bovine lenses. Mass spectral analysis of the peptide preparations obtained from these lenses demonstrated the presence of a peptide (T20) containing an intact C-terminus from fetal lenses and the presence of an additional peptide (T20') from older lenses that contained a cleaved C-terminal serine. These results demonstrate an age-dependent processing of alpha-A crystallin in the bovine lens, resulting in removal of the C-terminal amino acid residue.
NASA Discipline Cell Biology↗
MEMS-Based Force-Detected Nuclear Magnetic Resonance (FDNMR) Spectrometer
Nuclear Magnetic Resonance (NMR) spectroscopy allows assignment of molecular structure by acquiring the energy spectrum of nuclear spins in a molecule, and by interpreting the symmetry and positions of resonance lines in the spectrum. As such, NMR has become one of the most versatile and ubiquitous spectroscopic methods. Despite these tremendous successes, NMR experiments suffer from inherent low sensitivity due to the relatively low energy of photons in the radio frequency (rt) region of the electromagnetic spectrum. Here, we describe a high-resolution spectroscopy in samples with diameters in the micron range and below. We have reported design and fabrication of force-detected nuclear magnetic resonance (FDNMR).
force detected nuclear magnetic resonance (FDNMR)↗