RSI Nameplate
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Next Issue

Jan 2003

Volume 74, Issue 1, pp. 1-912

Page 2 of 10 Pages Previous Page Next Page | Jump to Page
back to top
RSS Feeds
back to top CONDENSED MATTER; MATERIALS

Kinematic viscosity meter utilizing the phase of pressure gradient variation

Ippei Torigoe

Rev. Sci. Instrum. 74, 164 (2003); http://dx.doi.org/10.1063/1.1523644 (4 pages)

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
A method is proposed for measuring the kinematic viscosity of a fluid. An exciter is mounted in a sensing channel and driven sinusoidally so as to vibrate the fluid within the channel. This vibration causes an axial pressure gradient variation that has two components: (1) a component proportional to the velocity and viscosity of fluid in the sensing channel and (2) a component proportional to the acceleration and density of the fluid. The ratio of these two components — the phase angle between the fluid velocity and the pressure gradient — is a function only of the vibration frequency and kinematic viscosity of the fluid. Since the frequency and phase of the fluid velocity vibration is known, the kinematic viscosity can be obtained from the phase of the pressure gradient variation. An experimental device that employs a loudspeaker as the vibration exciter and condenser microphones to detect the pressure gradient variation was constructed and several experiments were performed for air. The results show that the change in the kinematic viscosity due to a change in the air temperature can be measured successfully using the proposed kinematic viscosity meter utilizing the pressure gradient variation. © 2003 American Institute of Physics.
Show PACS
47.80.-v Instrumentation and measurement methods in fluid dynamics
62.10.+s Mechanical properties of liquids
47.60.-i Flow phenomena in quasi-one-dimensional systems
back to top CHEMISTRY

A beam scattering instrument for the dynamics studies of surface-induced dissociation processes

Anil K. Shukla and Jean H. Futrell

Rev. Sci. Instrum. 74, 168 (2003); http://dx.doi.org/10.1063/1.1524713 (8 pages) | Cited 6 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
A beam scattering instrument has been constructed to study the dynamics of ion-surface collisions, especially surface-induced dissociation of polyatomic ions. The instrument uses a bench top double focusing mass spectrometer as the source of a well-defined ion beam for transmission into a collision chamber. The primary ions are decelerated to desired ion energy (as low as 5 eV) by a series of tube lenses and collide the surface at 45°. Thus, the ion energy for surface-induced dissociations can be varied from ∼5 eV to ⩾1 keV. The secondary ions are energy and mass analyzed by a cylindrical energy analyzer and a quadrupole mass filter, respectively, and detected by a channel electron multiplier operating in pulse counting mode. The detector assembly can be rotated with respect to the collision center between the specular angle and surface parallel to measure intensity and energy distributions of scattered primary and fragment ions as a function of scattering angle. The newly constructed instrument has been tested for its performance and used to study the dissociation of ethanol molecular ions colliding with a self-assembled monolayer surface of fluorinated thiol on gold (111) crystal and first results are presented here. © 2003 American Institute of Physics.
Show PACS
07.75.+h Mass spectrometers
34.35.+a Interactions of atoms and molecules with surfaces
79.20.Rf Atomic, molecular, and ion beam impact and interactions with surfaces

Low-shear-rate capillary viscometer for polymer solution intrinsic viscosity determination at varying temperatures

T. S. Rushing and R. D. Hester

Rev. Sci. Instrum. 74, 176 (2003); http://dx.doi.org/10.1063/1.1529302 (6 pages) | Cited 1 time

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
A low-shear capillary viscometer has been designed, constructed, and used to measure polymer solution intrinsic viscosities over temperatures ranging from 10 to 75 °C. The instrument is capable of detecting the small shear stress forces produced when low-viscosity fluids are subjected to very low-shear rates. Instrument performance and sensitivity were evaluated using deionized water at temperatures between 10 and 75 °C. The measured water viscosity values differed from the literature values by less than 1%. The viscometer was also used to determine that the intrinsic viscosity of a poly(acrylamide) aqueous solution at 29 °C was 17.7 dL/g. This value was in agreement with the value obtained using a Contraves Low-Shear 30 cup and bob rheometer, 17.9 dL/g. © 2003 American Institute of Physics.
Show PACS
83.80.Rs Polymer solutions
83.85.Jn Viscosity measurements
66.20.-d Viscosity of liquids; diffusive momentum transport
47.50.-d Non-Newtonian fluid flows
back to top BIOLOGY and MEDICINE

Wide-field time-resolved fluorescence anisotropy imaging (TR-FAIM): Imaging the rotational mobility of a fluorophore

J. Siegel, K. Suhling, S. Lévêque-Fort, S. E. D. Webb, D. M. Davis, D. Phillips, Y. Sabharwal, and P. M. W. French

Rev. Sci. Instrum. 74, 182 (2003); http://dx.doi.org/10.1063/1.1519934 (11 pages) | Cited 22 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
We report a picosecond time-gated fluorescence lifetime imaging (FLIM) system extended to perform time-resolved fluorescence anisotropy imaging (TR-FAIM). Upon excitation with linearly polarized laser pulses, the parallel and perpendicular components of the fluorescence emission from a sample are imaged simultaneously using a polarization-resolved imager. The imaging technique presented here quantitatively reports the rotational mobility of a fluorophore as it varies according to the local environment. In a single acquisition run it yields maps of both rotational correlation time and fluorescence lifetime as they vary across a sample. TR-FAIM has been applied to imaging standard multiwell plate samples of rhodamine 6G dissolved in methanol, ethylene glycol, trimethylene glycol, and glycerol. The observed rotational correlation times and fluorescence lifetimes, which report the local viscosity and refractive index of the local rhodamine 6G environment, respectively, are in good agreement with previously published single point measurements. By considering the linear dependence of the rotational correlation time on viscosity up to 20 cP, we are able to obtain a two-dimensional viscosity map. Wide-field maps of rotational correlation time, and therefore viscosity, have been obtained. This illustrates the potential to image the local viscosity and fluorescence lifetime distributions of fluorophore tagged proteins in cells. © 2003 American Institute of Physics.
Show PACS
87.80.-y Biophysical techniques (research methods)
78.47.-p Spectroscopy of solid state dynamics
66.20.-d Viscosity of liquids; diffusive momentum transport
87.15.M- Spectra of biomolecules
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Optical workstation with concurrent, independent multiphoton imaging and experimental laser microbeam capabilities

David L. Wokosin, Jayne M. Squirrell, Kevin W. Eliceiri, and John G. White

Rev. Sci. Instrum. 74, 193 (2003); http://dx.doi.org/10.1063/1.1524716 (9 pages) | Cited 15 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
Experimental laser microbeam techniques have become established tools for studying living specimens. A steerable, focused laser beam may be used for a variety of experimental manipulations such as laser microsurgery, optical trapping, localized photolysis of caged bioactive probes, and patterned photobleaching. Typically, purpose-designed experimental systems have been constructed for each of these applications. In order to assess the consequences of such experimental optical interventions, long-term, microscopic observation of the specimen is often required. Multiphoton excitation, because of its ability to obtain high-contrast images from deep within a specimen with minimal phototoxic effects, is a preferred technique for in vivo imaging. An optical workstation is described that combines the functionality of an experimental optical microbeam apparatus with a sensitive multiphoton imaging system designed for use with living specimens. Design considerations are discussed and examples of ongoing biological applications are presented. The integrated optical workstation concept offers advantages in terms of flexibility and versatility relative to systems implemented with separate imaging and experimental components. © 2003 American Institute of Physics.
Show PACS
87.64.mn Multiphoton
07.60.Pb Conventional optical microscopes
42.60.Jf Beam characteristics: profile, intensity, and power; spatial pattern formation
42.62.Be Biological and medical applications
back to top GRAVITY; GEOPHYSICS; ASTRONOMY and ASTROPHYSICS

A low-energy charged particle distribution imager with a compact sensor for space applications

D. J. Knudsen, J. K. Burchill, K. Berg, T. Cameron, G. A. Enno, C. G. Marcellus, E. P. King, I. Wevers, and R. A. King

Rev. Sci. Instrum. 74, 202 (2003); http://dx.doi.org/10.1063/1.1525869 (10 pages) | Cited 13 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
Low-energy plasmas having temperatures of order 1 eV or less are found commonly in the ionospheres and space environments of Earth and other planets. Measuring the density, temperature, drift velocities, phase-space anisotropies, and other properties of these plasmas presents numerous challenges. Examples are distortions of particle trajectories due to spacecraft wakes, spacecraft charging, and particle gyromotion in magnetized plasmas. Furthermore, these plasmas are known to organize into structures as small as tens of meters across, traversed by spacecraft in tens of milliseconds or less. The Suprathermal Plasma Imager (SPI) was developed to address these challenges. The SPI is optimized for measurements of particles with ∼1 eV energies, and of the suprathermal extension of those populations up to several hundred eV. The SPI is sensitive to particle flux intensities of order 6×105 cm−2 s−1 sr−1 eV−1 and greater. It produces 3024-pixel images corresponding to two-dimensional (angle/energy) cuts through plasma velocity distribution functions, with an image frame rate of up to 100 s−1. The SPI has a cylindrical sensor head measuring 37.5 mm in diameter and 14 cm long, with a mass of 350 g. The relatively small size and mass of the sensor allow it to be deployed easily on a boom, outside of the spacecraft’s electrical sheath and in a region where wake perturbations are reduced. The SPI sensor head contains no electronic circuitry, but instead creates a visible image of the particle distribution with a system of dc-biased grids, microchannel plates, and a phosphor screen. The phosphor image is transferred via an imaging fiber-optic cable to an instrument box in the main spacecraft body, where it is sampled with a charge-coupled device and support electronics. Inside the sensor, angle/energy images of incident particle distributions are formed by a pair of concentric hemispherical grids. The incident energies Ei accessible to the analyzer lie in the range 0 ⩽ Ei ⩽ Emax where Emax ≈ qΔV/3, ΔV being the potential difference between the hemispheres. For an ideal analyzer, energy resolution ΔE/E is ⩽22% over most of the imaged energy range, degrading at energies below Emax/10. Angular resolution varies from 2° to 8° full width at half maximum between Emax and Emax/10. Energy and angular resolutions are degraded in the presence of a potential difference between the sensor and surrounding plasma. A 37.5-mm-diam version of the analyzer with a 0.86-mm-wide aperture has an ideal energy-dependent geometry factor of ≈ 5×10−4 eV sr cm2 for a square detector pixel of width 0.28 mm. Laboratory testing shows degraded energy resolution compared to ideal values, due in part to particle scattering within the analyzer. The SPI was tested successfully in flight on the GEODESIC auroral sounding rocket on 26 February 2000. © 2003 American Institute of Physics.
Show PACS
94.80.+g Instrumentation for space plasma physics, ionosphere, and magnetosphere
07.87.+v Spaceborne and space research instruments, apparatus, and components (satellites, space vehicles, etc.)
94.20.wc Plasma motion; plasma convection; particle acceleration
94.20.Tt Ionospheric soundings; active experiments
52.70.Ds Electric and magnetic measurements
52.30.-q Plasma dynamics and flow

Development of a spring ring for microchannel plate stack fastening in the cosmic hot interstellar plasma spectrometer detector

Mario Marckwordt

Rev. Sci. Instrum. 74, 212 (2003); http://dx.doi.org/10.1063/1.1527204 (6 pages)

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
This article describes the development of the spring ring used to fasten the microchannel plate (MCP) stack of the cosmic hot interstellar plasma spectrometer (CHIPS) detector. Fastening criteria specific to the CHIPS detector is developed, although the method is applicable to any MCP detector design with cylindrical symmetry. The basic equations from spring disk theory are presented along with appropriate simplifying approximations. Design criteria and test data of the final CHIPS flight version is reviewed, including comparison to results obtained with different materials and processing steps. © 2003 American Institute of Physics.
Show PACS
95.55.Vj Neutrino, muon, pion, and other elementary particle detectors; cosmic ray detectors
42.79.Ls Scanners, image intensifiers, and image converters
85.60.Ha Photomultipliers; phototubes and photocathodes
29.40.Mc Scintillation detectors

Feedforward reduction of the microseism disturbance in a long-base-line interferometric gravitational-wave detector

J. A. Giaime, E. J. Daw, M. Weitz, R. Adhikari, P. Fritschel, R. Abbott, R. Bork, and J. Heefner

Rev. Sci. Instrum. 74, 218 (2003); http://dx.doi.org/10.1063/1.1524717 (7 pages) | Cited 10 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
Standing ocean waves driven by storms can excite surface waves in the ocean floor at twice the wave frequency. These traverse large distances on land and are called the double-frequency (DF) microseism. The Laser Interferometer Gravitational-wave Observatory (LIGO) detector relies on length servos to maintain optical resonance in its 4 km Fabry–Pérot cavities, which consist of seismically isolated in-vacuum suspended test mass mirrors in three different buildings. Correcting for the DF microseism motion can require tens of micrometers of actuation, a significant fraction of the feedback dynamic range. The LIGO seismic isolation design provides an external fine actuation system (FAS), which allows long-range displacement of the optical tables that support the test mass suspensions. We report on a feedforward control system that uses seismometer signals from each building to produce correction signals, which are applied to the FAS, largely removing the microseism disturbance independently of length control servos. The root-mean-squared displacement from the microseism near 0.15 Hz can be reduced by 10 dB on average. © 2003 American Institute of Physics.
Show PACS
04.80.Nn Gravitational wave detectors and experiments
07.60.Ly Interferometers
95.55.Ym Gravitational radiation detectors; mass spectrometers; and other instrumentation and techniques
back to top ELECTRONICS; ELECTROMAGNETIC TECHNOLOGY; MICROWAVES

Completely explosive pulsed power minisystem

E. F. Talantsev, S. I. Shkuratov, J. C. Dickens, and M. Kristiansen

Rev. Sci. Instrum. 74, 225 (2003); http://dx.doi.org/10.1063/1.1527719 (6 pages) | Cited 7 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
It is demonstrated that it is feasible to produce pulsed power using an autonomous completely explosive system that harnesses two physical phenomena successively: the transverse shock wave demagnetization of Nd2Fe14B high-energy hard ferromagnets and magnetic cumulation. © 2003 American Institute of Physics.
Show PACS
84.70.+p High-current and high-voltage technology: power systems; power transmission lines and cables
75.50.Bb Fe and its alloys
75.50.Ww Permanent magnets
75.80.+q Magnetomechanical effects, magnetostriction
75.60.Ej Magnetization curves, hysteresis, Barkhausen and related effects
back to top THERMOMETRY; THERMAL DIFFUSIVITY; ACOUSTIC; PHOTOTHERMAL and PHOTOACOUSTIC

±30 μK temperature controller from 25 to 103 °C: Study and analysis

P. K. Madhavan Unni, M. K. Gunasekaran, and A. Kumar

Rev. Sci. Instrum. 74, 231 (2003); http://dx.doi.org/10.1063/1.1529299 (12 pages) | Cited 6 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
A simple two-stage metal thermostat, having a wide tolerance, has been built for performing light scattering studies in multicomponent liquid systems. It gives a temperature stability of ±30–45 μK for 1½ h and ±60–90 μK for 7–14 h over a broad range of 25–103 °C. A detailed profile of thermal gradients within the sample recess is provided. The parameter ΔTeff [i.e., the difference between the maximum (minimum if ΔTeff has a negative value) temperature within the sample recess and the temperature just outside the sample recess] seems to be more relevant than ΔT (i.e., the temperature difference between the inner and the outer stages) in understanding the behavior of our thermostat. The thermal gradients can be tuned by varying ΔTeff (or by varying ΔT). The least values of horizontal and vertical thermal gradients, i.e., 250 and 100 μK/mm, respectively, are observed for ΔTeff = 4.46 mK. The transient response of the controller is almost invariant for ΔTeff>0, but it shows a dramatic decrease of almost 50% when ΔTeff<0. On the whole, the limit ΔTeff → 0, provides the best operating condition from all standpoints. A simple and effective compensation scheme to null the effect of extraneous parameters is employed. The importance of the stability of the bridge excitation source in improving the long-term stability of the controller is established. © 2003 American Institute of Physics.
Show PACS
07.07.Tw Servo and control equipment; robots
07.20.-n Thermal instruments and apparatus
84.32.Ff Conductors, resistors (including thermistors, varistors, and photoresistors)

Low noise temperature control: Application to an active cavity radiometer

Bruno Guillet, Didier Robbes, and Laurence Méchin

Rev. Sci. Instrum. 74, 243 (2003); http://dx.doi.org/10.1063/1.1525872 (7 pages) | Cited 4 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
We have designed low noise temperature sensing and control units with the objective of using them for the fabrication of far infrared active cavity radiometers. The sensing unit, first characterized at 300 K using industrial platinum resistance thermometers, has a noise level of ∼ 25–30 μKeff for a 3 h measuring time and in a 1 Hz bandwidth. Using YBCO superconducting thermometers, the noise level goes down to 2.5 μKeff, which is strongly limited by excess 1/f noise in the YBCO film at the superconducting transition. The sample holder used in the 90 K experiments is built with an auxiliary heating resistor, which enables an easy and accurate identification of the electrothermal model, even in the closed loop operation. Based on a design previously published by NIST, we estimate from these experimental results that the overall noise limitations of radiometers could be lowered by one order of magnitude. © 2003 American Institute of Physics.
Show PACS
07.57.Kp Bolometers; infrared, submillimeter wave, microwave, and radiowave receivers and detectors
07.20.Dt Thermometers
07.07.Tw Servo and control equipment; robots

Rare-earth doped optical fiber approach to an alarm system for fire and heat detection

T. Sun, K. T. V. Grattan, W. M. Sun, S. A. Wade, and B. D. Powell

Rev. Sci. Instrum. 74, 250 (2003); http://dx.doi.org/10.1063/1.1527203 (6 pages)

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
A fluorescence based optical fiber fire alarm system has been further refined in this work to determine the presence of a localized temperature excursion (as low as 50–100 °C) against a varying background at temperatures up to 500–600 °C. © 2003 American Institute of Physics.
Show PACS
42.81.Pa Sensors, gyros
07.20.-n Thermal instruments and apparatus
78.55.Qr Amorphous materials; glasses and other disordered solids
42.55.Wd Fiber lasers
back to top GENERAL INSTRUMENTS

Phase shifting focused ion beam moiré method

Huimin Xie, Haixia Shang, Biao Li, and Fulong Dai

Rev. Sci. Instrum. 74, 256 (2003); http://dx.doi.org/10.1063/1.1525871 (4 pages) | Cited 4 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
In this article, a phase shifting technique for focused ion beam (FIB) moiré method is proposed, which is able to measure the full field in-plane deformation of an object in a micrometer scale. The FIB moiré is generated by the interference between a prepared specimen grating and FIB raster scan lines. The principle of phase shifting technique for FIB moiré is described in detail. With this method, phase shifting was realized in four steps from 0 to 2 π by shifting the focused ion beam controlled by a FIB system. This method is successfully used to measure the virtual deformation in a micro-electro-mechanical system structure with a 2500 lines/mm grating. The experiments prove the validity of this technique and show its ability of determine the full field strain with high accuracy. © 2003 American Institute of Physics.
Show PACS
07.78.+s Electron, positron, and ion microscopes; electron diffractometers
07.10.Pz Instruments for strain, force, and torque
07.10.Cm Micromechanical devices and systems

The extended surface forces apparatus. Part III. High-speed interferometric distance measurement

M. Zäch, J. Vanicek, and M. Heuberger

Rev. Sci. Instrum. 74, 260 (2003); http://dx.doi.org/10.1063/1.1527199 (7 pages) | Cited 3 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
In this communication, we describe a photoelectric setup used to monitor the wavelength of a spectral line at sampling rates exceeding 1 kHz. A split photodiode was chosen as the position-sensitive element. Its operation, calibration, and performance are discussed in terms of the interferometric distance measurement in the surface forces apparatus. We demonstrate how the normalized difference signal from the photodiode can be transformed into surface separation and that the extension of the experimental window allows for the acquisition of up to ten force-versus-distance curves per second. Provided that the detector is sufficiently small, we find a linear relationship between the surface separation and the normalized photodetector signal. We illustrate the experimental setup in detail, including the necessary signal-evaluation circuitry. The main difficulties associated with this high-speed approach are low light levels and noise. Optimizing the spectral intensity, keeping the detector area small, designing the evaluation circuits carefully, as well as normalizing the photodetector signal are some of the measures that were found to improve overall performance. Calibration of the device against an absolute distance measurement using a charge coupled device camera as well as its statistical and systematic errors are discussed. The curved nature of the interference fringes and associated implications on the distance determination are considered. © 2003 American Institute of Physics.
Show PACS
06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)
07.60.Ly Interferometers
85.60.Dw Photodiodes; phototransistors; photoresistors
42.79.Pw Imaging detectors and sensors
85.60.Gz Photodetectors (including infrared and CCD detectors)
06.20.F- Units and standards
07.68.+m Photography, photographic instruments; xerography
06.60.Jn High-speed techniques (microsecond to femtosecond)
back to top
RSS Feeds

A vertical inertial coarse approach for variable temperature scanned probe microscopy

William R. Silveira and John A. Marohn

Rev. Sci. Instrum. 74, 267 (2003); http://dx.doi.org/10.1063/1.1524712 (3 pages) | Cited 7 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
We have developed a variable temperature inertial coarse approach mechanism for use in scanned probe microscopy. This reliable micropositioner has a coarse range of 2.5 mm and can take individual steps of less than 10 nm from 4 to 300 K. This simple, compact device is both nonmagnetic and glueless. It is operational in both horizontal and vertical geometries and is driven by a low voltage sawtooth waveform. We report on the design and performance of the device. © 2003 American Institute of Physics.
Show PACS
07.79.Lh Atomic force microscopes
06.60.Sx Positioning and alignment; manipulating, remote handling

Modified Michelson fiber-optic interferometer: A remote low-coherence distributed strain sensor array

Libo Yuan

Rev. Sci. Instrum. 74, 270 (2003); http://dx.doi.org/10.1063/1.1525867 (3 pages)

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
A simple modified Michelson fiber-optic low-coherence interferometric quasi-distributed sensing system permitting absolute length measurement in remote reflective sensor array is proposed. The sensor reflective signals characteristics have been analyzed and the relationship between light signal intensities and sensors number was given for multiplexing potential evaluation. The proposed sensing scheme will be useful for the remote measurement of strain. An important application could be deformation sensing in smart structures. Experimentally, a three sensors array has been demonstrated. © 2003 American Institute of Physics.
Show PACS
42.81.Pa Sensors, gyros
07.60.Vg Fiber-optic instruments
07.07.Df Sensors (chemical, optical, electrical, movement, gas, etc.); remote sensing
07.10.Pz Instruments for strain, force, and torque
07.60.Ly Interferometers
42.25.Kb Coherence
06.30.Bp Spatial dimensions (e.g., position, lengths, volume, angles, and displacements)

Environmental chamber for powder x-ray diffractometers for use at elevated pressures and low temperatures

A. F. Koster van Groos, Stephen Guggenheim, and Curt Cornell

Rev. Sci. Instrum. 74, 273 (2003); http://dx.doi.org/10.1063/1.1525868 (3 pages) | Cited 6 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
An elevated-pressure, low-temperature environmental chamber was developed for the Bruker (Siemens) D-5000 theta-theta goniometer-based powder x-ray diffractometer. With minor modifications, the chamber is applicable to all models of theta-theta goniometers from any manufacturer. The chamber is capable of pressures to about 100 bars and temperatures from −50 °C to 200 °C (with silicone seals), based on conservative best estimates. Diffractometer scans may be made between 0° and 70° two theta. © 2003 American Institute of Physics.
Show PACS
07.35.+k High-pressure apparatus; shock tubes; diamond anvil cells
07.85.Jy Diffractometers
61.05.cp X-ray diffraction

Lifetime measurement and calibration from pressure-sensitive paint luminescence images

T. F. Drouillard, M. A. Linne, L. P. Goss, J. R. Gord, and G. J. Fiechtner

Rev. Sci. Instrum. 74, 276 (2003); http://dx.doi.org/10.1063/1.1527201 (3 pages) | Cited 1 time

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
A dual-image lifetime technique for acquiring surface pressure measurements from pressure-sensitive paint image data has been developed. This technique eliminates the need to acquire a “wind-off” reference image as required by the traditional radiometric technique, which is known to corrupt results. Here a luminescence lifetime-versus-pressure calibration experiment was conducted. Uncertainty was nominally less than ±4% and decreased as signal level increased. The nominal sensitivity was less than ±5 Torr at 100 Torr, less than ±50 Torr at 700 Torr, and improved with signal level. © 2003 American Institute of Physics.
Show PACS
06.20.F- Units and standards
78.60.Mq Sonoluminescence, triboluminescence
back to top
RSS Feeds
back to top SPECTROSCOPY, ANALYTICAL CHEMISTRY, AND PHOTOCHEMISTRY

Practical analysis of polymers with depth varying compositions using Fourier transform infrared photoacoustic spectroscopy (plenary)

John F. McClelland, Roger W. Jones, and Siquan Luo

Rev. Sci. Instrum. 74, 285 (2003); http://dx.doi.org/10.1063/1.1516244 (6 pages) | Cited 2 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
Fourier transform infrared photoacoustic spectroscopy can be used as a nondestructive method to probe the molecular composition of materials as a function of depth into the sample. This is done by varying the thickness of the surface layer being analyzed, which can be as great as some tens of micrometers, depending on optical and thermal properties. Computational methods are described to process photoacoustic amplitude and phase spectra for both semiquantitative and quantitative depth analyses. These methods are demonstrated on layered and gradient samples. © 2003 American Institute of Physics.
Show PACS
82.80.Kq Energy-conversion spectro-analytical methods (e.g., photoacoustic, photothermal, and optogalvanic spectroscopic methods)
43.58.Kr Spectrum and frequency analyzers and filters; acoustical and electrical oscillographs; photoacoustic spectrometers; acoustical delay lines and resonators
81.70.Cv Nondestructive testing: ultrasonic testing, photoacoustic testing
07.57.Ty Infrared spectrometers, auxiliary equipment, and techniques

Thermal lens temperature scanning for quantitative measurements in transparent materials (invited)

J. H. Rohling, J. R. D. Pereira, A. N. Medina, A. C. Bento, M. L. Baesso, J. A. Sampaio, S. M. Lima, T. Catunda, and L. C. M. Miranda

Rev. Sci. Instrum. 74, 291 (2003); http://dx.doi.org/10.1063/1.1517157 (6 pages) | Cited 2 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
In this work the ability of thermal lens spectrometry for different temperature studies in transparent materials is discussed. The method was applied in polymers and optical glasses to measure the thermo-optical properties as a function of the temperature. The focus of the discussion will be on the temperature range where the glass transition occurs. The perspectives of future studies in this area will be discussed. © 2003 American Institute of Physics.
Show PACS
78.20.N- Thermo-optic effects
78.20.nb Photothermal effects
64.70.P- Glass transitions of specific systems
64.70.Q- Theory and modeling of the glass transition
78.20.Ci Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)

Effect of sensitization by quantum-sized CdS on photoacoustic and photoelectrochemical current spectra of porous TiO2 electrodes

Taro Toyoda, Jun Sato, and Q. Shen

Rev. Sci. Instrum. 74, 297 (2003); http://dx.doi.org/10.1063/1.1515898 (3 pages) | Cited 13 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
We report the optical absorption characteristics of highly porous, polycrystalline TiO2 electrodes, on which CdS nanocrystal particles are adsorbed, measured by the photoacoustic (PA) method together with the photoelectrochemical (PEC) current characteristics. The PA spectrum shifts to the lower photon energy region and the intensity below the band-gap energy of TiO2 increases rapidly with an increase in the number of CdS coating layers to 20 and becomes almost constant at more than 20 layers, indicating the possibility of the growth of CdS coated layers. The increase in PEC current intensity and a clear shift of spectra to the lower photon energy region are observed with the increased number of CdS coated layers, indicating the possibility of the transfer of photoexcited electrons of the CdS nanocrystals to the TiO2 conduction band. The PEC current spectrum shifts to the lower photon energy region and the intensity below the band-gap energy of TiO2 increases rapidly with an increase of in the number of CdS coating layers to 20 and decreases with a further increase in the number of layers coated to 40. Thus, nanocrystals of low-band-gap semiconductors are suitable for the sensitization of TiO2 PEC solar cells as well as dye sensitization. © 2003 American Institute of Physics.
Show PACS
72.40.+w Photoconduction and photovoltaic effects
82.45.Fk Electrodes
78.20.hb Piezo-optical, elasto-optical, acousto-optical, and photoelastic effects
61.46.-w Structure of nanoscale materials

The effects of eluent’s optothermal parameters on TLS detection in gradient HPLC

J. Kožar Logar and M. Franko

Rev. Sci. Instrum. 74, 300 (2003); http://dx.doi.org/10.1063/1.1515899 (3 pages) | Cited 5 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
The effects of changing solvent composition on the limits of detection (LOD) of thermal lens spectroscopy (TLS) detection in gradient elution HPLC have been studied from the perspective of solvent’s thermooptical properties. The refractive index and the temperature dependence of refractive index were measured and are reported for the first time for the methanol-acetone and methanol-ammonium acetate solutions used in this work, and some other methanol based chromatographic eluents. The TLS signal noise during a gradient HPLC protocol is increasing and its value reaches the maximum with a considerable time delay (up to 3 min) compared to the end point of the gradient protocol. The length of the chromatographic column was found to be an important parameter in reduction of signal noise resulting from incomplete solvent mixing. For some carotenoids the LOD values on the order of 50–100 pg/mL can be obtained on a 25 cm column with solvents that yield an increase in TLS enhancement factor up to 1.6 times during the gradient HPLC analysis. © 2002 American Institute of Physics.
Show PACS
82.80.Bg Chromatography
82.80.Kq Energy-conversion spectro-analytical methods (e.g., photoacoustic, photothermal, and optogalvanic spectroscopic methods)

Buffer-gas pressure influence on multiphoton absorption in SF6–N2 mixtures

D. D. Markushev, M. Terzić, and J. Jovanović-Kurepa

Rev. Sci. Instrum. 74, 303 (2003); http://dx.doi.org/10.1063/1.1515900 (3 pages) | Cited 3 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
In this article the results of pulsed IR photoacoustic spectroscopy measurements of multiphoton absorption and relaxation processes in SF6–N2 mixtures are presented. The total average number of absorbed photons per one absorbing molecule (basic physical quantity which characterized multiphoton processes) during the laser pulse 〈n〉total is used and analyzed with a generalized coupled two-level model. This type of analysis is based on buffer-gas pressure (pbuff) functional behavior of 〈n〉total and calculation of its partial values depending on collisions, 〈n〉coll, and laser fluence, 〈n〉Φ, influence. Using different methods of photoacoustic spectroscopy, collisionaly induced rotational and vibrational to translational relaxation process parameters (τrot and τV-T, respectively) are quantitatively obtained and used to determine partial values of 〈n〉coll, 〈n〉rot, and 〈n〉V-T. It will be shown that a method based on ∂〈n〉total/∂p functional dependence on pbuff and laser fluence Φ can be used to confirm or predict the existence of some processes during the laser pulse, such as dissociation or strong vibrational to vibrational energy transfer, which can contribute to the total amount of energy absorbed into the investigated sample. This could allow one to apply this method and control laser field–molecule interaction in different gas mixtures, and help one to understand multiphoton absorption processes in detail. © 2003 American Institute of Physics.
Show PACS
32.80.Wr Other multiphoton processes
33.80.Gj Diffuse spectra; predissociation, photodissociation
34.50.Ez Rotational and vibrational energy transfer

Determination of physical parameters of conducting polymers by photothermal spectroscopies

J. E. de Albuquerque, W. L. B. Melo, and R. M. Faria

Rev. Sci. Instrum. 74, 306 (2003); http://dx.doi.org/10.1063/1.1515901 (3 pages) | Cited 19 times

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
Photothermal spectroscopies, photopyroelectric and photoacoustic, were used to obtain physical parameters of polyaniline–emeraldine base (PANI-EB) and poly(o-methoxyaniline)–emeraldine base (POMA-EB), such as thermic parameters like thermal diffusivity, thermal conductivity, and specific heat. These studies were done for PANI-EB and POMA-EB films in the 400<λ<900 nm wavelength range. The photopyroelectric intensity Vn(f ) and the phase Fn(f ) (f being the chopping frequency) for a given λ of the saturation part of the PPES spectrum signal were independently measured, as well as the intensity Vn(λ) and its phase Fn(λ). Equations of both the intensity and the phase of the PPES signal, taking into account the thermal and the optical characteristics of the PANI and POMA films and the pyroelectric detector, were used to fit the experimental results. It was observed that, in contrast with the strong doping dependence of the electrical conductivity, the thermal parameters of PANI films remained practically unchanged under doping. This apparent discrepancy is explained by the granular metal model of doped PANI. © 2003 American Institute of Physics.
Show PACS
78.66.Qn Polymers; organic compounds
07.60.Rd Visible and ultraviolet spectrometers
07.20.-n Thermal instruments and apparatus
78.20.N- Thermo-optic effects
78.20.nb Photothermal effects

Photoacoustic spectral studies on lanthanide amino acid complexes

Yue-tao Yang, Gui-wen Zhao, and Shu-yi Zhang

Rev. Sci. Instrum. 74, 309 (2003); http://dx.doi.org/10.1063/1.1515902 (3 pages) | Cited 1 time

Online Publication Date: 16 January 2003

Full Text: | Download PDF

Show Abstract
Several kinds of lanthanide complexes with glycine, alanine, phenylalanine, and tryptophan were synthesized and their photoacoustic (PA) spectra were measured. For the complexes of weakly fluorescent lanthanide ions with amino acids, the PA spectra reflect the influences of the ligands on the energy levels of lanthanide ions, whereas for the complexes of fluorescent lanthanide ions with amino acids, the PA spectra can be used to study the energy transfer from aromatic amino acids to lanthanide ions. At last, separating the overlapping peaks of lanthanide complex with tryptophan using the PA phase resolved method is introduced. © 2003 American Institute of Physics.
Show PACS
78.20.hb Piezo-optical, elasto-optical, acousto-optical, and photoelastic effects
Page 2 of 10 Pages Previous Page Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close