bluuebunny/crossref_metadata_2025 huggingface dataset:
Raman Spectra of Haloaluminate Melts Containing Oxides
Authors: Gilbert B. P. , Berg R. W. , Bjerrum N. J.
Published: June 2005

Raman spectroscopy measurements on haloaluminate melts (bromides and chlorides), with or without addition of the corresponding aluminum oxohalide, have unequivocally shown that even the most carefully cleaned melts exhibit a polarized Raman band, due to the presence of aluminum oxohalide complexes. The frequency of this characteristic oxide Raman band is ∼280–270 cm−1 for the chloride and ∼185 cm−1 for the bromide system, respectively. Hence, being halide dependent, the observed band cannot be assigned entirely to Al-O vibrations within the skeleton of the aluminum oxohalide species but must also involve some movement of the halide atoms. At temperatures just above the melting point, studies of the oxide band intensity vs. time showed that molten AlCl3 and AlBr3 attack Pyrex® glass, fused quartz, and sapphire containers, causing dissolution of oxides; within few hours, the melts become almost saturated. Finally, it has been found that acidic chloroaluminate melts, which invariably tend to fluoresce when illuminated with visible light contained in a glass or silicate container, owe their fluorescing properties to a reaction between the container and the AlCl3. This troublesome fluorescence can be quenched by addition to the melt of a reductant such as metallic aluminum.
SERS Observation of the Adsorption Behavior of O2, H2O, and SO2 on Silver Powder Surfaces at Nearly Real Environmental Conditions
Authors: Matsuta Hideyuki , Hirokawa Kichinosuke
Published: June 2005

The interaction of O2, H2O, and SO2 on silver powder prepared from the reduction of AgNO3 by NaBH4 was studied by surface-enhanced Raman scattering (SERS) at room temperature. The presence of H2O of about 103 Pa and O2 of about 104-105 Pa was necessary for observation of SERS peaks of SO32− and SO42−. The superoxide ion O2- was observed under high partial pressure for O2 conditions. SERS peaks of atomic oxygen, superoxide ion O2-, SO32−, and SO42− disappeared on evacuation. SERS peaks of surface species such as Ag2O did not disappear on evacuation.
Optogalvanic Measurement of the Electric Field inside the Cathode Fall Region of Neon Hollow Cathode Discharge
Authors: Ami Norihiro , Wada Akihide , Adachi Yukio , Hirose Chiaki
Published: June 2005

Radial distribution of the electric field in the cathode fall region of neon hollow cathode discharge has been derived through the observation of the linear Stark effect of the nd′ ( n = 10–12)-3 p′[½]1 transitions by two-step optogalvanic spectroscopy. The field strength was found to decrease monotonically from the cathode to the negative glow. The depth of the cathode fall region was 0.80 ± 0.05 mm, and the electric field at the cathode surface was 5.2 ± 0.2 kV/cm*—values which compare with the reported values of around 3–4 mm and 3–4 kV/cm in the cathode fall region of Ne glow discharge. The difference and similarity in the values of derived parameters are discussed.
A Study of Natural and Synthetic Rubies by PIXE
Authors: Tang S. M. , Tang S. H. , Mok K. F. , Retty A. T. , Tay T. S.
Published: June 2005

Trace element analysis of 160 natural- and synthetic rubies was carried out by using the technique of proton-induced x-ray emission (PIXE). It was found that the natural rubies contained more and higher concentrations of impurities than did their synthetic counterparts. Our results suggest that vanadium and iron are good indicators for separating synthetic rubies from the natural ones. The concentration of chromium is also helpful in many cases for source identification.
Absorption and Coherent Interference Effects in Multiply Resonant Four-Wave Mixing Spectroscopy
Authors: Carlson Roger J. , Wright John C.
Published: June 2005

The effects of coherent interference between resonant and nonresonant signals and the effects of absorption on multiresonant four-wave mixing spectra are investigated both theoretically and experimentally in azu-lene-doped naphthalene crystals at 2 K. Both effects can strongly alter line shapes and intensities. Line splittings and negative spectral features are demonstrated. Coherent interference, although measurable in this system, is weak. Absorption, however, plays an important role, and its effects on phase matching, peak shapes, and peak intensities are predicted theoretically and are confirmed by the experimental measurements. A new expression for the four-wave mixing is derived in terms of sample absorption coefficients and absorption cross sections, and general conditions for maximum efficiency are determined.
The KBM Equation for Solvent-Induced Frequency Shifts Revisited
Authors: Nyquist R. A.
Published: June 2005

The KBM equation for determining solvent frequency shifts is generally useless for predicting vC = O frequencies for compounds in various solvent systems. The vC = O frequencies for acetone and tetramethylurea in various solvents do not correlate with dielectric effects (ε) of the solvent. A series of factors most likely determine the extent of solute/solvent-induced vibrational mode frequency shifts.
X-Ray Photoelectron-Spectroscopic Studies of Carbon Fiber Surfaces. Part IX: The Effect of Microwave Plasma Treatment on Carbon Fiber Surfaces
Authors: Xie Yaoming , Sherwood Peter M. A.
Published: June 2005

X-ray photoelectron spectroscopy has been used to monitor the surface chemical changes occurring on type II carbon fibers exposed to air, oxygen, and nitrogen plasmas. In all cases the plasmas caused changes in surface functionality, in terms of both C-O and C-N functionality. Prolonged exposure to the plasmas caused loss of surface functionality for air and oxygen plasmas, and extended treatment caused fiber damage. Plasma treatment of fibers promises to be an effective method of fiber treatment.
Determination of Trace Metals and Their Distribution in Heavy Crude Oil Distillates (350°C+) by Atomic Absorption Spectrophotometry
Authors: Zaki Nabila S. , Barbooti Mahmood M. , Baha-Uddin Sulafa S. , Hassan Eman B.
Published: June 2005

The concentration of Cu, Fe, Na, Ni, and V were determined in four heavy distillates from three heavy crude oils and one commercial crude oil by atomic absorption spectrophotometry. The distillates were extracted by DMF in order to estimate the porphyrinic (extract) and nonporphyrinic (residue) fractions of V and Ni contents. The V was distributed almost equally between the two types, while most of the Ni content was in the nonporphyrinic form. The asphaltene and resin fractions of the distillates were isolated and analyzed for their Ni and V contents. It appeared that about 90% of these metallic species of the distillates were concentrated in these two fractions, which in turn share these metallic compounds equally.
Easily and Noneasily Ionizable Element Matrix Effects in Inductively Coupled Plasma Optical Spectrometry
Authors: Olesik John W. , Williamsen Eric J.
Published: June 2005

Changes in analyte emission intensities occur when either easily or non-easily ionizable elements are present as concomitant species at a concentration of 0.05 M. The direction (enhancement or depression of emission signals) and magnitude of the matrix effect are strongly dependent on radial and vertical location in the plasma. At some heights in the ICP, matrix-induced depressions of the emission intensity in the center are equal to enhancements off-center. As a result, no change in the line-of-sight emission intensity is observed. Initial fluorescence measurements suggest that the number of analyte ions in the normal analytical zone decreases in the presence of each of the concomitant species studied. However, it appears that the presence of concomitant species enhances the fraction of ions that are excited and that therefore emit light. The presence of Na and K resulted in larger enhancements in the fraction of ions excited than did the presence of Fe, Ni, or Ba.
Molecular Orbital Study of Reaction Processes in the Thermospray Mass Spectra of Deuterated Penicillins
Authors: Siegel Marshall M. , Colthup Norman B.
Published: June 2005

Mass spectra of penicillin compounds were generated with the use of a thermospray mass spectrometer interface and deuterated solvents. Deuterium ion addition sites to the parent ion and the substituted ketene and thiazoline fragment ions were investigated with the use of molecular orbital calculations for computing the relative proton affinities for the various ion isomers. The energetics of the beta-lactam ring cleavage, which generates the fragment ions, were calculated, as well as the energetics of various C-H to C-D hydrogen-deuterium exchange processes, which generate the substituted ketene fragment ions. The calculations afforded the identification of the most probable structures for the generated ions.
Ionization of Organic Molecules Using Coherent Vacuum Ultraviolet Light
Authors: Arps J. H. , Chen C. H. , McCann M. P. , Datskou I.
Published: June 2005

Third harmonic generation in xenon was used to produce vacuum ultraviolet light at a fixed wavelength of 118 nm. These photons were able to ionize a number of organic molecules with negligible yields of fragmentation ions. This method yielded far simpler mass spectra than those utilizing electron impact ionization. Absolute photoionization cross sections were measured for six organic compounds at 118.2 nm.
Quantitative Fourier Self-Deconvolution and Fourier Transform Infrared Analysis of Bisphenol-A-Polycarbonate/Poly(Dimethylsiloxane) Random Block Copolymers
Authors: Mittlefehldt Eric R. , Gardella Joseph A.
Published: June 2005

Fourier self-deconvolution (FSD) is used to enhance the spectral resolution of Fourier transform infrared results obtained from thick solution-cast films of bisphenol-A-polycarbonate-poly(dimethylsiloxane) blends and random block copolymers. Despite the severity of band overlap in the region from 1300 to 1200 cm−1, accurate determinations of bulk composition are made from the deconvolved absorbance (transmission mode) spectra of eleven blends and three random block copolymers. With compositions expressed in terms of each component's relative concentration, these results are used to develop a multicomponent Beer's law relationship that is verified through the determination of appropriate homopolymer absorptivities. Fourier transform infrared attenuated total reflectance results are compared to the multicomponent Beer's law relationship in an effort to quantitate the surface excess of siloxane 0.004–1.6 µm from the air/solid interface.
Inductively Coupled Plasma Mass Spectrometry as a Detector for Micellar Liquid Chromatography: Speciation of Alkyltin Compounds
Authors: Suyani Hamzar , Heitkemper Douglas , Creed John , Caruso Joseph
Published: June 2005

Inductively coupled plasma mass spectrometry has been used as a detector for several organotin compounds which were separated with the use of micellar liquid chromatography. Trimethyltin chloride, triethyltin bromide, and tripropyltin chloride were separated with a 0.1 M sodium dodecyl sulfate (SDS) micellar mobile phase and C-18 stationary phase. Detection limits for the three were 27, 51, and 111 picograms tin, respectively. A 0.02 M SDS mobile phase was used to separate monomethyltin trichloride, dimethyltin dichloride, and trimethyltin chloride. Detection limits for these compounds were 46, 26, and 126 picograms tin, respectively. Preliminary separation of those five organotin compounds was obtained by gradient elution. Calibration curves were linear over 3.5 orders of magnitude. The relative standard deviation for ten 100-μL injections containing 4 ng tin ranged from 1.3 to 1.9% with a 0.1 M SDS mobile phase and from 3.4 to 4.8% with a 0.02 M SDS mobile phase.
Vibrational Frequency Shifts of the Carbonyl Stretching Mode Induced by Solvents: Acetone
Authors: Nyquist R. A. , Kirchner T. M. , Fouchea H. A.
Published: June 2005

Variation in the correlations obtained between electron acceptor number (AN) values for each solvent versus the vC=O frequencies for acetone and tetramethylurea in solution with these solvents suggests that the AN values are not a precise measure of solute/solvent interaction for all solute/solvent systems. Factors such as intermolecular hydrogen bonding between solute and solvent and the differences between molecular geometry of the solutes and solvents most likely account for differences in the solute/solvent interaction for different solutes in the same solvents.
Solvent and Concentration Effects on Carbonyl Stretching Frequencies: Ketones
Authors: Nyquist R. A. , Putzig C. L. , Yurga L.
Published: June 2005

Hydrogen bonding, dielectric effects, and steric effects are all factors which determine the carbonyl stretching frequency, vC=O, of ketones in solution. The vC=O frequency for ketones shifts continuously at constant concentration in solutions of CHCl3/CCl4 with change in the mole ratio of the two solvents. The vC=O frequency is also affected by change in concentration in either CCl4 or CHCl3 solution.
Real-Time Laser Spark Spectroscopy of Particulates in Combustion Environments
Authors: Ottesen D. K. , Wang J. C. F. , Radziemski L. J.
Published: June 2005

Several laser-based techniques are being developed to provide in situ determinations of size, velocity, and elemental composition for individual particulates in combustion environments. Emphasis is placed on composition measurements using laser spark spectroscopy, and data for particulates entrained in gaseous flows are presented. Size and velocity of individual particles are determined by a colinear two-color laser scattering technique. Laser sparks (high-temperature plasmas) are produced from single particles with the use of a Q-switched Nd:YAG laser, and time-resolved emission spectra are observed. Results indicate a high sensitivity of the technique to mineral matter in coal particles. The detection of numerous constituent species is demonstrated, and trends observed in elemental distribution are in agreement with x-ray fluorescence measurements. Initial semi-quantitative results are compared with standard chemical analyses of the bulk material.
Surface Characterization and CO Hydrogenation Activity of Silane-Treated Nickel/Aluminas
Authors: Otowa Toshiro , Houalla Marwan , Hercules David M. , Kibby Charles L. , Petrakis Leonidas
Published: June 2005

High-surface-area supported nickel-silicon alloys were prepared by treating Ni/Al2O3 with silane (SiH4) at 300–400°C in flowing hydrogen. Microbalance studies indicated that the supported nickel-silicon alloys were easily decomposed, compared with alloys prepared by bulk melting. However, the decomposed alloys were difficult to reduce, indicating formation of an interaction species. ESCA and ISS studies indicate that silane treatment brings about considerable shielding of the nickel surface which coincides with a drastic decrease in CO hydrogenation activity.
Ion Bombardment Magnetron Furnace for Atomic Spectroscopy
Authors: Tanguay Suzanne , Sacks Richard
Published: June 2005

Positive-ion bombardment of a graphite cathode in a low-pressure glow discharge is used to heat the cathode to temperatures in excess of 2000°C. A magnetic field of a few hundred Gauss used in a magnetron configuration reduces lamp voltage and permits operation at less than 1 kV with cathode current densities greater than 350 mA/cm2. A solution residue sample deposited on the 1.6-mm-diameter graphite cathode is atomized in about one second. The atomic vapor is excited in the glow discharge near the cathode surface. The effects of pressure and magnetic field strength on furnace performance are described. At low furnace temperature, plasma current conduction is by electrons produced by positive ion bombardment of the cathode surface. At higher temperatures, current conduction is largely by thermionic electrons.
Multiple Harmonic Electron Paramagnetic Resonance Spectroscopy by Simultaneous Detection
Authors: Shimoyama Yuhei , Watari Hiroshi
Published: June 2005

A simultaneous measurement method was developed to permit the multiple detection of the first- and second-order harmonic displays of electron paramagnetic resonance (EPR) spectra. Application of integration and differentiation of amplitude and phase simultaneously, i.e., vector operations on the various displays, enables identification of signals expressed by the various harmonics. By using simultaneous detection, we found for the first time that signals indicated by the different displays are not always identical. The transformation from the first to the second harmonic displays (or vice versa) by vector operations indicated that the displays were not interchangeable when nonlinear response was involved. Simultaneous detection proved to be useful for measurements of the electron spin relaxation where multiple signals coexist. The present detection system provides a means for multivector EPR spectroscopy.
Parametric Study of a Low-Pressure Theta-Pinch Discharge in Argon for Preliminary Analytical Optimization
Authors: White Jeffrey S. , Lee Gae Ho , Scheeline Alexander
Published: June 2005

The qualitative dependence of spectrochemical performance of a thetapinch discharge on a variety of experimental variables including discharge gas pressure, sample positioning, discharge energy, and discharge current waveform is reported.
Solvent Effect Correlations for Acetone: IR versus NMR Data for the Carbonyl Group
Authors: Nyquist R. A. , Putzig C. L. , Hasha D. L.
Published: June 2005

A linear relationship is found to exist between the carbonyl stretching frequency ( vC=O) and the carbon-13 chemical shift data [δ(13C=O)] for the carbonyl group of 0.345 mole % acetone in a mixed solvent solution ranging from 1.5 to 70.8 mole % CHCl3/CCl4. The correlation shows that as vC=O decreases in frequency δ(13C=O) increases in frequency as the concentration of CHCl3 increases in the acetone/CHCl3/CCl4 solutions. However, the relationship between vC=O and the mole % CHCl3/CCl4 and between δ(13C=O) and the mole % CHCl3/CCl4 is not linear over the concentration range studied. Both hydrogen bonding and bulk dielectric effects most likely contribute to the change in both the IR and NMR data with change in the CHCl3/CCl4 ratio.
Examinations of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part XVI
Authors: Coleman W. M. , Gordon Bert M.
Published: June 2005

Information concerning the matrix isolation Fourier transform infrared spectra of a series of alkanes, esters, lactones, lactams, phenols, alcohols, amides, alkenes, and ketones is presented. A comparison between the characteristics of the spectra in two matrices (argon and xenon) as well as in the absence of any matrix (bare gold disk) is drawn. The impact of these matrices on the characteristics of the IR spectra is compared with the impact observed when spectra are gathered in the vapor phase as well as the condensed phase/solid state. For the majority of compounds studied, the major absorption bands of each class of compound fall between higher values for the vapor phase and lower values for the condensed phase when either argon or xenon is used as the matrix gas. The few exceptions are discussed. The absorption bands found in the xenon matrix are usually at a lower energy than are comparable bands in the argon matrix. In most all cases, the values of absorptions for compounds on the bare disk were lower than the comparable values found in the argon matrix. These results represent the first extensive study at 10 K of the effect of different matrix gas hosts and document the proposal that preconceptions of noble gases as inert hosts for the examination of FT-IR spectra at low temperature are not valid.
Determination of Water Loss Mechanism in Amine Terminous Amino Acids Using Laser Mass Spectrometry
Authors: Rosnack Kenneth J. , Somayajula Kasi V. , Sharkey Andrew G. , Jensen Nancy J. , Hercules David M.
Published: June 2005

The water loss process in Laser Mass Spectrometry of amine terminal amino acids was studied. Water loss is proposed to occur via a thermal decomposition mechanism for a protonated amino acid forming a protonated lactam ring. The magnitude of the water loss peak is correlated with the stability of the protonated lactam ring. Semi-empirical MNDO calculations of the heat of reaction of a protonated amino acid forming a protonated lactam ring and water support the correlation. The substrate (matrix) appears to have little effect on the process; results are essentially the same with the use of different substrates and sample preparation methods.
Radiative and Electrical Properties of a Planar Magnetron Glow Discharge Device
Authors: McCaig Lori , Sacks Richard , Lubman David
Published: June 2005

A glow discharge with a planar cathode in a curved magnetic field is described. The device relies on gradient drift, curvature drift, and electrostatic reflection of electrons to obtain high cathodic sputtering rates at unusually low voltages and pressures. Gradient drift and curvature drift of electrons occur when the magnetic field is inhomogeneous or nonlinear, respectively. The device is characterized in the pressure range from 1.0 to 0.01 Torr. Line intensities from cathodically sputtered material are highest, and continuum background intensity lowest, at pressures less than 0.06 Torr. Design features and performance data are considered.
A Linear Charge-Coupled Device Detector System for Spectroscopy
Authors: Sweedler Jonathan V. , Jalkian Rafi D. , Denton M. Bonner
Published: June 2005

The spectroscopically important performance capabilities of a linear charge-coupled device detector system, along with the methods used to evaluate the detector performance, are described. The linearity, read noise, full-well capacity, charge transfer efficiency, and ultraviolet to near-infrared quantum efficiency of the detector are presented along with the methods required to operate the detector in unconventional modes allowing low noise and antiblooming operation. With the antiblooming mode of operation, the detector performance is shown to be unaffected by light overloads hundreds of times over the saturation level. The performance of the detector for high-resolution diagnostic studies of hollow cathode lamps as well as for molecular fluorescence is presented.
Laser Mass Spectra of Liquids Taken at Ambient Pressure
Authors: Morelli John J. , Hercules David M.
Published: June 2005

Laser mass spectra have been obtained for liquids under ambient conditions; the spectra are identical with those for the same compounds with the use of cold probe (∼100 K). Liquids studied include benzene, toluene, benzyl alcohol, benzaldehyde, and acetic acid. Under the conditions employed, water, ethanol, methanol, and glycerol do not yield mass spectra. Laser mass spectra are compared with the electron-impact and chemical ionization spectra of the same compounds. Relative ion yields for benzene were studied as a function of laser irradiance. Two ion-formation regimes can be identified: low-power density and high-power density. Cluster ions were observed for many compounds, and the effect of postacceleration voltage on relative cluster-ion intensity is indicated.
Attenuation of Polyatomic Ion Interferences in Inductively Coupled Plasma Mass Spectrometry by Gas-Phase Collisions
Authors: Rowan John T. , Houk R. S.
Published: June 2005

A double quadrupole arrangement to remove polyatomic ions by collisions with an added target gas has been evaluated. The ions Ar2+, ArO+, and ArN+ were attenuated by factors of 50–400 to count rates of ≤100 counts s−1. Fifty to seventy percent of the analyte ions were retained. Removal of polyatomic ions and retention of analyte ions were favored by low-energy collisions with Xe or CH4 rather than typical target gases like N2 or Ar. Products of ion-molecule reactions between background ions and target gas in the first quadrupole could be observed.
Fluorescence Lifetime and Quenching Rates for N,N,N′,N′-Tetramethyl-P-Phenylenediamine in the Vapor Phase
Authors: Nickle S. K. , Melton L. A.
Published: June 2005

The fluorescence lifetime of N,N,N′,N′-tetramethyl- p-phenyIenediamine (TMPD) in the vapor phase has been determined to be 3.2 ± 0.3 ns for excitation at 337 nm. The rate constants for quenching of electronically excited TMPD by ground-state TMPD, O2, and CO2 have been determined to be <1 × 10−10 cm3/s, (9.9 ± 1.0) × 10−10 cm3/s, and <4 × 10−13 cm3/s, respectively. The rate for TMPD implies that self-quenching is negligible up to pressures of at least 10 Torr. The quenching rate by oxygen is sufficiently high to ensure that use of TMPD as a quantitative marker for fuel evaporation in exciplex-based vapor/liquid visualization systems is probably not possible if significant quantities of oxygen—as would be the case in combustion environments—are present.
Reduction of Mass-Dependent Interferences in Inductively Coupled Plasma-Mass Spectrometry by using Flow-Injection Analysis
Authors: Vickers George H. , Ross Barbara S. , Hieftje Gary M.
Published: June 2005

The use of flow-injection analysis to reduce mass-dependent interferences in inductively coupled plasma-mass spectrometry has been assessed. Results are presented which demonstrate nearly complete elimination of analyte-signal suppression under operating conditions where dispersion ( D) is approximately 25. Furthermore, results obtained with flow-injection analysis exhibit greater precision, take less time, and suffer only a 40% reduction in sensitivity, compared to continuous-flow analysis.
The Optical Rotatory Dispersion and Linear Dichroism Option of the JASCO J-500 A-Type CD Spectropolarimeter
Authors: Shindo Yohji , Hayakawa Hiroshi , Sudani Masahiro
Published: June 2005

We have made an ORD option for our JASCO J-500 A-type CD spectrometer based on the know-how obtained from the studies of our new polarization-modulation spectrometer. The Mueller matrix approach is used to analyze and evaluate important factors determining the performance of our ORD option. These are (1) the harmonic rejection and “in band” overload capability of the lock-in amplifier, (2) the position of the analyzer's optical axis, (3) the residual static birefringence of the PEM. The capability of our ORD option is equal to that of commercially available ORD spectropolarimeters, in the range from 200 to 700 nm. Furthermore, our option has much faster speed for ORD measurements than does the ORD spectropolarimeter of the null-point detection type. Our ORD option can also be used to measure linear dichroism in high sensitivity.
A Perspective on University Research and Graduate Studies in Japan
Authors: Coleman David M.
Published: June 2005

Several facets of education and research in a Japanese university are discussed. Many similarities exist (relative to the U.S.A.); nonetheless, numerous cultural and organizational differences profoundly influence the nature of graduate studies in Japan. Graduate education in the Minami Laboratory of Scientific Instrumentation and Measurement Engineering, Department of Applied Physics, Osaka University, is featured. Some particulars relative to undertaking a long-term research stay in Japan are also included.
The Light-Induced Yellowing of Paper Studied by Second-Derivative DRIFT Spectroscopy
Authors: Michell A. J. , Nelson P. J. , Garland C. P.
Published: June 2005

The light-induced yellowing of the surface of paper made from a Eucalyptus regnans chemimechanical pulp has been studied by using second-derivative diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy in the region 1550 to 1800 cm−1. The observed reflectances were transformed to Kubelka-Munk units and the second derivatives obtained. Use of the second derivative technique has resulted in reduced bandwidths, enabling bands such as that at 1612 cm−1 arising from exocyclic C=C bonds in lignin to be resolved from the broad envelope of the strong C=C ring stretching band at 1591 cm−1. The improved resolution has enabled the effects of UV light on the population of potential chromophoric C=0 and C=C groups in paper surfaces to be studied more precisely.
Mixed Alkali Halide Dilution Matrices for Diffuse Reflectance Infrared Spectrometry: Effect of Particle Size
Authors: Tevrucht Mollie L. E. , Griffiths Peter R.
Published: June 2005

Diffuse reflectance Fourier transform infrared spectra of coal diluted in two different alkali halide matrices were compared. Pure KBr and mixed CsI/KBr were tested for use as dilution matrices. When the variable of particle size was controlled, KBr was found to be the better diluent.
New Developments in Fourier Transform Infrared Vibrational Circular Dichroism Measurements
Authors: Polavarapu P. L.
Published: June 2005

A new FT-IR vibrational circular dichroism (VCD) spectrometer has been assembled to record VCD spectra with excellent signal quality up to ∼650 cm−1. A special detector with 600 cm−1 cutoff ( D* = 4 × 1010), a ZnSe modulator, and a KRS-5 polarizer were used in these measurements. Typical VCD spectra at 4 cm−1 resolution can be obtained within a one-hour data acquisition period, while those at 1 cm−1 resolution, in the ∼ 1500-650 cm−1 region, can be obtained within four hours of data acquisition per sample. VCD spectra for ã-pinene, 3-bromocamphor, and propylene oxide are presented.
Gas Chromatographic/Matrix Isolation/Fourier Transform Infrared Spectra of the Laterally Chlorinated Dibenzo-p-Dioxins and Dibenzofurans
Authors: Wurrey Charles J. , Fairless Billy J. , Kimball Harry E.
Published: June 2005

Reference-quality gas chromatographic/matrix isolation/Fourier transform infrared spectra have been recorded for the following fifteen compounds, which collectively are referred to as the “laterally” chlorinated dibenzo- p-dioxins and dibenzofurans: 2,3,7,8-tetrachlorodibenzo- p-dioxin (2,3,7,8-TCDD); 1,2,3,7,8-pentachlorodibenzo- p-dioxin (1,2,3,7,8-PeCDD);l,2,3,4,7,8-hexachlorodibenzo- p-dioxin(1,2,3,4,7,8-HxCDD)>; 1,2,3,6,7,8,-hexachlorodibenzo- p-dioxin(1,2,3,6,7,8-HxCDD); 1,2,3,7,8,9-hexachlorodibenzo- p-dioxin (1,2,3,7,8,9-HxCDD); 1,2,3,4,6,7,8-heptachlorodibenzo- p-dioxin (1,2,3,4,6,7,8-HpCDD); 2,3,7,8-tetrachlorodibenzofuran (2,3,7,8-TCDF); 1,2,3,7,8-pentachlorodibenzofuran (1,2,3,7,8-PeCDF); 2,3,4,7,8-pentachlorodibenzofuran (2,3,4,7,8-PeCDF); 1,2,3,4,7,8-hexachlorodibenzofuran(1,2,3,4,7,8-HxCDF); 1,2,3,6,7,8-hexachlorodibenzofuran (1,2,3,6,7,8-HxCDF); 1,2,3,7,8,9-hexachlorodibenzofuran (1,2,3,7,8,9-HxCDF); 2,3,4,6,7,8-hexachlorodibenzofuran (2,3,4,6,7,8-HxCDF); 1,2,3,4,6,7,8-heptachlorodibenzofnran (1,2,3,4,6,7,8-HpCDF); and 1,2,3,4,7,8,9-heptachlorodibenzofuran (1,2,3,4,7,8,9-HpCDF). These spectra are discussed qualitatively and, for the laterally chlorinated dioxins, are compared to previously recorded gas-phase GC/FT-IR spectra. Estimates of the instrumental detection limits for these compounds, using matrix isolation GC/FT-IR spectroscopy, were found to fall in the mid-to-high picogram and low nanogram ranges.
Wavelength Stability with an Injection-Locked Excimer Laser
Authors: Vickers Thomas J. , Mann Charles K. , Chong Chan Kong , Zhu Jianxiong
Published: June 2005

Linewidth and wavelength measurements have been made on the emission from an injection-locked KrF laser to address questions which have been raised about the suitability of this device for UV resonance Raman measurements. To the extent that any wavelength jitter occurs, it is less than 0.004 Å. We conclude that the KrF excimer laser is a relatively robust source of UV radiation for Raman measurements.
A Window Fourier-Domain Infrared Search System
Authors: Sherman Jeffrey W. , de Haseth James A. , Cameron David G.
Published: June 2005

A search system is presented that utilizes Fourier-domain infrared data. This system removes or nulls features from infrared absorbance spectra that are found to be dominant and similar in the spectra of interest. This method enhances spectral differences. An example of one such region that is commonly nulled is the C-H stretch region of the spectra. These bands occur in organic compounds and, while generally being quite strong, contribute little to differentiation between spectra. More than one region may be nulled with this system, and the regions are chosen by visual inspection of the spectra of interest. The nulled spectra are then transformed into the Fourier domain, where data in the region that is 55–155 points displaced from the centerburst are extracted and normalized. Finally, a complete library search is performed on the normalized Fourier-domain data. The actual matching algorithm uses a simple dot product calculation, and excellent search results are obtained. This method can be used to distinguish similar compounds that are not easily distinguished by other infrared search methods. In the most difficult cases, a minimum of two-orders-of-magnitude improvement in the difference in dot products is observed when the results of full bandpass spectra are compared with the results of spectra that had one or more regions nulled.
The Application of ICP Spectroscopy to Model the Chemistry Occurring in Plasma-Etch Reactors: Part I
Authors: Mautz Karl E. , Parsons Michael L. , Moore Carleton B.
Published: June 2005

ICP spectroscopy utilizing both gaseous and/or liquid sample introduction was used to model chemical components produced in plasma etch reactors. Single plasma gas chemistries including Ar and CF4 and additive gas systems of CHF3-O2 and CF4-O2 were characterized with the use of a dispersive monochromatoir/photodiode array detection system. Experimental techniques and equipment comparisons of plasma sources and detection systems for plasma chemistry modeling are discussed. Identification of atomic and molecular species produced in each plasma source for these gas chemistries and sample components was determined and compared.
An Investigation of the Relationship between Cotton Fineness and Light Scattering from Thin Webs as Measured by Near-Infrared Transmission Spectroscopy
Authors: Montalvo Joseph G. , Faught Sherman E. , Buco Steven M.
Published: June 2005

Near-infrared transmission spectroscopy (NITS) is applied to thin cotton webs to measure fiber fineness (expressed either as specific surface—the external surface area per unit weight of fiber—or as cross-sectional perimeter). We report here the development and successful testing of a mathematical model that predicts a linear relationship between fineness and light-scattering intensity (optical density, log 1/ T) by a thin cotton web. With a thin web of fibers in the light beam, absorption of photons out of the beam is negligible. When the detector is placed several inches from the web, only the photons passing between the fibers strike the light detector. Photons that strike a fiber are scattered out of the light beam and away from the detector. Thus the fineness of the fiber controls the propagation of light to the detector. The premise that specific surface is proportional to optical density when the weight of fiber in the light beam is constant is shown experimentally (probability, p < 0.0045). Also, the premise that perimeter is proportional to optical density when the total length of fiber in the light beam is constant is shown experimetally ( p < 0.0070). These results are based on analysis of 9 cottons; 810 webs were produced, computer sorted by weight, and the scatter spectra recorded for 360 webs.
Analysis of EPDM Terpolymers by Near-Infrared Spectroscopy and Multivariate Calibration Methods
Authors: Miller Charles E.
Published: June 2005

Near-infrared spectroscopy in the combination, first overtone, and second overtone regions is combined with the multivariate methods of Partial-Least-Squares (PLS) and Classical-Least-Squares (CLS) to provide calibrations for chemical components in ethylene-propylene-diene monomer (EPDM) terpolymers. EPDM samples with 1,4-hexadiene (HD) and ethylidene norbornene (ENB) diene monomers were used for this study. Because unknown interaction effects are present in the spectra of these materials, the PLS calibration method gives more accurate calibrations than the CLS method. PLS coefficient spectra and CLS reconstructed spectra obtained from the calibrations are used to determine the sources of the unknown spectral effects. Results indicate that the combination, first overtone, and second overtone regions of the spectrum can be used to determine ethylene and propylene concentrations in the terpolymers, and the combination region can be used to determine diene concentrations. The presence of intrachain and interchain interactions in the terpolymers is indicated by observation of CLS reconstructed spectra.
Pointing-Stability-Limited Dual-Beam Absorbance Measurements by Position-Sensitive Detection
Authors: Renn Curtiss N. , Synovec Robert E.
Published: June 2005

A HeCd laser was examined as a light source for dual-beam absorbance neasurements by position-sensitive detection. The measurement was limited by the laser point stability and, also, unspecified laser radiation that was effectively reduced by a spatial and spectral filter combination. An absorbance detection limit of 5 × 10−4 AU (3 × rms baseline noise) was predicted from an experimental optimization procedure. The detection limit was supported by microbore high-performance liquid chronatography of a B-2 vitamin sample, detecting riboflavin absorbance at 325 nm. Issues regarding the improvement of dual-beam absorbance measurements by position-sensitive detection are addressed.
Examinations of the Matrix Isolation Fourier Transform Infrared Spectra of Organic Compounds: Part XVII
Authors: Coleman W. M. , Gordon Bert M.
Published: June 2005

Qualitative and quantitative analysis of compounds in a complex mixture by gas chromatography/matrix isolation/Fourier transform infrared spectrometry (GC/MI/FT-IR) is described. The carbon-deuterium stretching mode was characterized and used for analysis since it has a unique position in the infrared spectrum. Compounds of varying functionalities were examined over a concentration range from 6 to 50 ng. Linear responses over this mass range were obtained. Flame ionization detection was used for collaborative detection in establishing the linearity of the responses. These results represent the first use of GC/MI/FT-IR for quantitative analysis of compounds in a complex mixture using deuterium-labeled analogues.
Automatic Sampling System Employing a Nebulizer for Solid-Surface Room-Temperature Phosphorescence Analysis
Authors: Campiglia A. D. , Perry L. M. , Winefordner J. D.
Published: June 2005

A new experimental system for the automation of Solid-Surface Room Temperature Phosphorescence (SSRTP) has been constructed. Samples were sprayed onto a moving filter paper by means of a conventional atomic absorption nebulizer. A new sample holder, which permits measurements of a previously optimized position for a maximum phosphorescent signal, has been designed and adapted to the cell compartment of the spectrofluorimeter. The results show that a considerable step has been taken towards the automation of SSRTP and, therefore, to its application in areas where numerous samples are handled routinely.
Fluorescence Quenching Studies of Near-Infrared Fluorophores
Authors: Andrews-Wilberforce Daniel , Patonay Gabor
Published: June 2005

Near-infrared laser dyes were studied with the use of conventional fluorescence quenching. A systematic study of the effects of different quenchers and temperature on the fluorescence of near-infrared fluorophores is presented. Differences in the quenching of near-infrared fluorophores were observed for quenching by ionic quenchers. Quenching with ionic and nonionic quenchers led to nonlinear quenching results.
Principal Component Analysis of Diffuse Near-Infrared Reflectance Data from Paper Currency
Authors: Dale John M. , Klatt Leon N.
Published: June 2005

Product tampering and product counterfeiting are increasing the need for methods to quickly determine product authenticity. One of the concepts that we are investigating for the detection of counterfeit objects involves the use of pattern recognition techniques to analyze multivariant data acquired from properties intrinsic to the object. The near-infrared reflectance spectra of currency and other paper stock were used as a test system. The sample population consisted of authentic currency, circulated and uncirculated, and cotton and rag paper stock as stand-ins for counterfeit currency. Reflectance spectra were obtained from a spot that was essentially void of printing on both sides of the currency specimens. Although the reflectance spectra for all of the samples were very similar, principal component analysis separated the samples into distinct classes without there being any prior knowledge of their chemical or physical properties. Class separation was achieved even for currency bills that differed only in their past environment. Leave-One-Out procedures resulted in 100% correct classification of each member of the sample set. A K-Nearest-Neighbor test or a linear discriminate can be used to correctly classify unknown samples.
Infrared Photoacoustic Spectroscopy of Carbon Black Filled Rubber: Concentration Limits for Samples and Background
Authors: Carter R. O. , Peck M. C. Paputa , Samus M. A. , Killgoar P. C.
Published: June 2005

Infrared spectroscopy studies of the cure chemistry, state of cure, and surface bloom on rubber materials have always been limited by the presence of carbon black in samples. One of the modern methods for recording infrared spectra of solid samples is photoacoustic detection Fourier transform spectroscopy. It has been demonstrated in the past that surface-segregated species can be identified with this technique, but the results are complicated by the presence of carbon black, which limits the optical depth. As for the study of bulk chemistry, photoacoustic detection does not require that the sample be infrared transparent, and the method can be used with samples containing as much as a 15 wt % carbon. At loadings higher than 30 wt %, the material becomes a total absorber and can be used to record an instrument background spectrum.
LTE Conditions within the Central Channel of the Plasma
Authors: Smith Thomas R. , Denton M. Bonner
Published: June 2005

Studies were performed on the effect of torch pressure on the excitation conditions within an inductively coupled plasma (ICP). Experimentally measured magnesium ion-to-atom ratios and electron densities were used to determine the deviation of the plasma from local thermodynamic equilibrium (LTE) conditions. Results of these studies indicate that the plasma is in an infrathermal state when operated at atmospheric pressure, and excitation conditions within the central channel of an ICP shift towards LTE conditions as torch pressure is increased.
Optimal Allocation in Designs for Assessing Heterosis From cDNA Gene Expression Data
Authors: Piepho Hans-Peter
Published: June 2005

Heterosis is defined as the superiority of a hybrid cross over its two parents. Plant and animals breeders have long been exploiting heterosis, but the causes of this phenomenon are as yet only partly understood. Recently, chip technology has opened up the opportunity to study heterosis at the gene expression level. This article considers the cDNA chip technology, which allows assaying two genotypes simultaneously on the same chip. Heterosis involves the response of at least three genotypes (two parents and their hybrid), so a chip or microarray constitutes an incomplete block, which raises a design problem specific to heterosis studies. The question to be answered is how genotype pairs should be allocated to chips. We address this design problem for two types of heterosis: midparent heterosis and better-parent heterosis. The general picture emerging from our results is that most of the resources should be allocated to parent-hybrid pairs, while chips with parent-parent pairs or hybrid-reciprocal pairs should be used sparingly or not at all.
RecD Plays an Essential Function During Growth at Low Temperature in the Antarctic Bacterium Pseudomonas syringae Lz4W
Authors: Regha K , Satapathy Ajit K , Ray Malay K
Published: June 2005

The Antarctic psychrotrophic bacterium Pseudomonas syringae Lz4W has been used as a model system to identify genes that are required for growth at low temperature. Transposon mutagenesis was carried out to isolate mutant(s) of the bacterium that are defective for growth at 4° but normal at 22°. In one such cold-sensitive mutant (CS1), the transposon-disrupted gene was identified to be a homolog of the recD gene of several bacteria. Trans-complementation and freshly targeted gene disruption studies reconfirmed that the inactivation of the recD gene leads to a cold-sensitive phenotype. We cloned, sequenced, and analyzed ∼11.2 kbp of DNA from recD and its flanking region from the bacterium. recD was the last gene of a putative recCBD operon. The RecD ORF was 694 amino acids long and 40% identical (52% similar) to the Escherichia coli protein, and it could complement the E. coli recD mutation. The recD gene of E. coli, however, could not complement the cold-sensitive phenotype of the CS1 mutant. Interestingly, the CS1 strain showed greater sensitivity toward the DNA-damaging agents, mitomycin C and UV. The inactivation of recD in P. syringae also led to cell death and accumulation of DNA fragments of ∼25–30 kbp in size at low temperature (4°). We propose that during growth at a very low temperature the Antarctic P. syringae is subjected to DNA damage, which requires direct participation of a unique RecD function. Additional results suggest that a truncated recD encoding the N-terminal segment of (1–576) amino acids is sufficient to support growth of P. syringae at low temperature.
Genetic Regulation of Gene Expression During Shoot Development in Arabidopsis
Authors: DeCook Rhonda , Lall Sonia , Nettleton Dan , Howell Stephen H
Published: June 2005

The genetic control of gene expression during shoot development in Arabidopsis thaliana was analyzed by combining quantitative trait loci (QTL) and microarray analysis. Using oligonucleotide array data from 30 recombinant inbred lines derived from a cross of Columbia and Landsberg erecta ecotypes, the Arabidopsis genome was scanned for marker-by-gene linkages or so-called expression QTL (eQTL). Single-feature polymorphisms (SFPs) associated with sequence disparities between ecotypes were purged from the data. SFPs may alter the hybridization efficiency between cDNAs from one ecotype with probes of another ecotype. In genome scans, five eQTL hot spots were found with significant marker-by-gene linkages. Two of the hot spots coincided with classical QTL conditioning shoot regeneration, suggesting that some of the heritable gene expression changes observed in this study are related to differences in shoot regeneration efficiency between ecotypes. Some of the most significant eQTL, particularly those at the shoot regeneration QTL sites, tended to show cis-chromosomal linkages in that the target genes were located at or near markers to which their expression was linked. However, many linkages of lesser significance showed expected “trans-effects,” whereby a marker affects the expression of a target gene located elsewhere on the genome. Some of these eQTL were significantly linked to numerous genes throughout the genome, suggesting the occurrence of large groups of coregulated genes controlled by single markers.