Science.gov

Sample records for 14-15 micron two-color

  1. 8-9 and 14-15 Micron Two-Color 640x486 GaAs/AlGaAs Quantum Well Infrared Photodetector (QWIP) Focal Plane Array Camera

    NASA Technical Reports Server (NTRS)

    Gunapala, S. D.; Bandara, S. V.; Singh, A.; Liu, J. K.; Rafol, S. B.; Luong, E. M.; Mumolo, J. M.; Tran, N. Q.; Vincent, J. D.; Shott, C. A.

    2000-01-01

    An optimized long-wavelength two-color Quantum Well Infrared Photodetector (QWIP) device structure has been designed. This device structure was grown on a three inch semi-insulating GaAs substrate by molecular beam epitaxy (MBE). This wafer was processed into several 640x486 format monolithically integrated 8-9 and 14-15 micron two color (or dual wavelength) QWIP focal plane arrays (FPAs). These FPAs were then hybridized to 640x486 silicon CMOS readout multiplexers. A thinned (i.e., substrate removed) FPA hybrid was integrated into a liquid helium cooled dewar to perform electrical and optical characterization and to demonstrate simultaneous two-color imagery. The 8-9 micron detectors in the FPA have shown background limited performance (BLIP) at 70 K operating temperature, at 300 K background with f/2 cold stop. The 14-15 micron detectors of the FPA have reached BLIP at 40 K operating temperature at the same background conditions. In this presentation we discuss the performance of this long-wavelength dualband QWIP FPA in quantum efficiency, detectivity, noise equivalent temperature difference (NEAT), uniformity, and operability.

  2. 8-9 and 14-15 meu Two-Color 640x486 GaAs/AlGaAs Quantum Well Infrared Photodetector (QWIP) Focal Plane Array Camera

    NASA Technical Reports Server (NTRS)

    Guanapala, S.; Bandara, S.; Singh, A.; Liu, J.; Rafol, S.; Luong, E.; Mumolo, J.; Tran, N.; Vincent, J.; Shott, C.; Long, J.; LeVan, P.

    1999-01-01

    An optimized long-wavelength two-color Quantum Well Infrared Phototdetector (QWIP) device structure has been designed. This device structure was grown on a three-inch semi-insulating GaAs substrate by molecular beam epitaxy (MBE).

  3. Two-color infrared detector

    DOEpatents

    Klem, John F; Kim, Jin K

    2014-05-13

    A two-color detector includes a first absorber layer. The first absorber layer exhibits a first valence band energy characterized by a first valence band energy function. A barrier layer adjoins the first absorber layer at a first interface. The barrier layer exhibits a second valence band energy characterized by a second valence band energy function. The barrier layer also adjoins a second absorber layer at a second interface. The second absorber layer exhibits a third valence band energy characterized by a third valence band energy function. The first and second valence band energy functions are substantially functionally or physically continuous at the first interface and the second and third valence band energy functions are substantially functionally or physically continuous at the second interface.

  4. Standard format two-color CMOS ROIC for SLS detectors

    NASA Astrophysics Data System (ADS)

    Simolon, Brian; Aziz, Naseem; Hansen, Randy; Kurth, Eric; Lam, Simon; Petronio, Susan; Woolaway, James

    2011-05-01

    The ISC0903 is a 320 × 256, standard format, two-color CMOS readout integrated circuit (ROIC) designed for strained-layer superlattice (SLS) detectors. The detector interface is supported through one input pad in each 30 micron pixel. One bit in the serial control word programs the chip to automatically adjust all biases and timing to allow for the integration of either electrons or holes. This feature allows users to easily operate this ROIC with a wide variety of p-on-n or n-on-p detectors. The ROIC has been specifically designed to allow for both polarities of detectors to be placed back-to-back and to connect to the ROIC through the one input pad to obtain a two-color image. The two-color image is achieved by switching the ROIC mode between the two colors on a per-frame basis. This paper will describe the interface, design, and features of the ISC0903 ROIC.

  5. Two-color QCD at high density

    NASA Astrophysics Data System (ADS)

    Boz, Tamer; Giudice, Pietro; Hands, Simon; Skullerud, Jon-Ivar; Williams, Anthony G.

    2016-01-01

    QCD at high chemical potential has interesting properties such as deconfinement of quarks. Two-color QCD, which enables numerical simulations on the lattice, constitutes a laboratory to study QCD at high chemical potential. Among the interesting properties of two-color QCD at high density is the diquark condensation, for which we present recent results obtained on a finer lattice compared to previous studies. The quark propagator in two-color QCD at non-zero chemical potential is referred to as the Gor'kov propagator. We express the Gor'kov propagator in terms of form factors and present recent lattice simulation results.

  6. Two-Color Laser Speckle Shift Strain Measurement System

    NASA Technical Reports Server (NTRS)

    Tuma, Margaret L.; Krasowski, Michael J.; Oberle, Lawrence G.; Greer, Lawrence C., III; Spina, Daniel; Barranger, John

    1996-01-01

    A two color laser speckle shift strain measurement system based on the technique of Yamaguchi was designed. The dual wavelength light output from an Argon Ion laser was coupled into two separate single-mode optical fibers (patchcords). The output of the patchcords is incident on the test specimen (here a structural fiber). Strain on the fiber, in one direction, is produced using an Instron 4502. Shifting interference patterns or speckle patterns will be detected at real-time rates using 2 CCD cameras with image processing performed by a hardware correlator. Strain detected in fibers with diameters from 21 microns to 143 microns is expected to be resolved to 15 mu epsilon. This system was designed to be compact and robust and does not require surface preparation of the structural fibers.

  7. Two-color quantum well infrared photodetector focal plane arrays

    NASA Astrophysics Data System (ADS)

    Bundas, Jason; Patnaude, Kelly; Dennis, Richard; Burrows, Douglas; Cook, Robert; Reisinger, Axel; Sundaram, Mani; Benson, Robert; Woolaway, James; Schlesselmann, John; Petronio, Susan

    2006-05-01

    QmagiQ LLC, has recently completed building and testing high operability two-color Quantum Well Infrared Photodetector (QWIP) focal plane arrays (FPAs). The 320 x 256 format dual-band FPAs feature 40-micron pixels of spatially registered QWIP detectors based on III-V materials. The vertically stacked detectors in this specific midwave/longwave (MW/LW) design are tuned to absorb in the respective 4-5 and 8-9 micron spectral ranges. The ISC0006 Readout Integrated Circuit (ROIC) developed by FLIR Systems Inc. and used in these FPAs features direct injection (DI) input circuitry for high charge storage with each unit cell containing dual integration capacitors, allowing simultaneous scene sampling and readout for the two distinct wavelength bands. Initial FPAs feature pixel operabilities better than 99%. Focal plane array test results and sample images will be presented.

  8. Two color far infrared laser interferometer

    SciTech Connect

    Kawahata, K.; Akiyama, T.; Pavlichenko, R.; Tanaka, K.; Tokuzawa, T.; Ito, Y.; Okajima, S.; Nakayama, K.; Wood, K.

    2006-10-15

    Two color interferometer using a short wavelength far infrared laser has been developed for high performance plasmas on large helical device and for future fusion devices such as ITER. High power laser lines simultaneously oscillating at 57.2 and 47.6 {mu}m were achieved in a CO{sub 2}-laser-pumped CH{sub 3}OD laser. By introducing Ge:Ga photoconductive detectors operating at liquid He temperature, we have successfully detected two color beat signals (0.55 and 1.2 MHz) with excellent signal-to-noise ratio ({approx}40 dB). These beat signals were fed into phase comparators for phase measurement after passing through intermediate frequency bandpass filters. Two color far infraned laser interferometer work was successful in the demonstration of mechanical vibration compensation.

  9. Wakefield generation via two color laser pulses

    SciTech Connect

    Jha, Pallavi; Saroch, Akanksha; Kumar Verma, Nirmal

    2013-05-15

    The analytical study for the evolution of longitudinal as well as transverse electric wakefields, generated via passage of two color laser pulses through uniform plasma, has been presented in the mildly relativistic regime. The frequency difference between the two laser pulses is assumed to be equal to the plasma frequency, in the present analysis. The relative angle between the directions of polarization of the two laser pulses is varied and the wakefield amplitudes are compared. Further, the amplitude of the excited wakes by two color pulses are compared with those generated by a single laser pulse.

  10. Demonstration of KHILS two-color IR projection capability

    NASA Astrophysics Data System (ADS)

    Jones, Lawrence E.; Coker, Jason S.; Garbo, Dennis L.; Olson, Eric M.; Murrer, Robert Lee, Jr.; Bergin, Thomas P.; Goldsmith, George C., II; Crow, Dennis R.; Guertin, Andrew W.; Dougherty, Michael; Marler, Thomas M.; Timms, Virgil G.

    1998-07-01

    For more than a decade, there has been considerable discussion about using different IR bands for the detection of low contrast military targets. Theory predicts that a target can have little to no contrast against the background in one IR band while having a discernible signature in another IR band. A significant amount of effort has been invested towards establishing hardware that is capable of simultaneously imaging in two IR bands to take advantage of this phenomenon. Focal plane arrays (FPA) are starting to materialize with this simultaneous two-color imaging capability. The Kinetic Kill Vehicle Hardware-in-the-loop Simulator (KHILS) team of the Air Force Research Laboratory and the Guided Weapons Evaluation Facility (GWEF), both at Eglin AFB, FL, have spent the last 10 years developing the ability to project dynamic IR scenes to imaging IR seekers. Through the Wideband Infrared Scene Projector (WISP) program, the capability to project two simultaneous IR scenes to a dual color seeker has been established at KHILS. WISP utilizes resistor arrays to produce the IR energy. Resistor arrays are not ideal blackbodies. The projection of two IR colors with resistor arrays, therefore, requires two optically coupled arrays. This paper documents the first demonstration of two-color simultaneous projection at KHILS. Agema cameras were used for the measurements. The Agema's HgCdTe detector has responsivity from 4 to 14 microns. A blackbody and two IR filters (MWIR equals 4.2 t 7.4 microns, LWIR equals 7.7 to 13 microns) were used to calibrate the Agema in two bands. Each filter was placed in front of the blackbody one at a time, and the temperature of the blackbody was stepped up in incremental amounts. The output counts from the Agema were recorded at each temperature. This calibration process established the radiance to Agema output count curves for the two bands. The WISP optical system utilizes a dichroic beam combiner to optically couple the two resistor arrays. The

  11. Phase control of two-color filamentation

    NASA Astrophysics Data System (ADS)

    Doussot, J.; Béjot, P.; Karras, G.; Billard, F.; Faucher, O.

    2015-09-01

    An original way to control the nonlinear propagation of an intense pulse is presented. The co-propagation of a weak (≃ 1%) third-harmonic pulse with an intense laser pulse experiencing filamentation allows control of the nonlinear propagation of the latter. Because of quantum interference during the two-color ionisation process, the latter can be significantly enhanced or suppressed by a simple tuning of the relative phase between the two fields. As a first application, we demonstrate the production and control of an axially modulated plasma channel. Finally, an analytical formula describing the two-color ionisation rate as a function of the relative phase and intensity of the two fields is presented and tested in a propagation code. The numerical results successfully reproduce the experimental ones.

  12. Millimeter accuracy satellites for two color ranging

    NASA Technical Reports Server (NTRS)

    Degnan, John J.

    1993-01-01

    The principal technical challenge in designing a millimeter accuracy satellite to support two color observations at high altitudes is to provide high optical cross-section simultaneously with minimal pulse spreading. In order to address this issue, we provide, a brief review of some fundamental properties of optical retroreflectors when used in spacecraft target arrays, develop a simple model for a spherical geodetic satellite, and use the model to determine some basic design criteria for a new generation of geodetic satellites capable of supporting millimeter accuracy two color laser ranging. We find that increasing the satellite diameter provides: a larger surface area for additional cube mounting thereby leading to higher cross-sections; and makes the satellite surface a better match for the incoming planar phasefront of the laser beam. Restricting the retroreflector field of view (e.g. by recessing it in its holder) limits the target response to the fraction of the satellite surface which best matches the optical phasefront thereby controlling the amount of pulse spreading. In surveying the arrays carried by existing satellites, we find that European STARLETTE and ERS-1 satellites appear to be the best candidates for supporting near term two color experiments in space.

  13. Optimum wavelengths for two color ranging

    NASA Technical Reports Server (NTRS)

    Degnan, John J.

    1993-01-01

    The range uncertainties associated with the refractive atmosphere can be mitigated by the technique of two color, or dual wavelength, ranging. The precision of the differential time of flight (DTOF) measurement depends on the atmospheric dispersion between the two wavelengths, the received pulsewidths and photoelectron counts, and on the amount of temporal averaging. In general, the transmitted wavelengths are not independently chosen but instead are generated via nonlinear optics techniques (harmonic crystals, Raman scattering, etc.) which also determine their relative pulsewidths. The mean received photoelectrons at each wavelength are calculated via the familiar radar link equation which contains several wavelength dependent parameters. By collecting the various wavelength dependent terms, one can define a wavelength figure of merit for a two color laser ranging system. In this paper, we apply the wavelength figure of merit to the case of an extremely clear atmosphere and draw several conclusions regarding the relative merits of fundamental-second harmonic, fundamental-third harmonic, second-third harmonic, and Raman two color systems. We find that, in spite of the larger dispersion between wavelengths, fundamental-third harmonic systems have the lowest figure of merit due to a combination of poor detector performance at the fundamental and poor atmospheric transmission at the third harmonic. The fundamental-second harmonic systems (approximately 700 nm and 350 nm) have the highest figure of merit, but second-third harmonic systems, using fundamental transmitters near 1000 nm, are a close second. Raman-shifted transmitters appear to offer no advantage over harmonic systems because of the relatively small wavelength separation that can be achieved in light gases such as hydrogen and the lack of good ultrashort pulse transmitters with an optimum fundamental wavelength near 400 nm.

  14. Two color holographic interferometry for microgravity application

    NASA Technical Reports Server (NTRS)

    Trolinger, James D.

    1993-01-01

    Holographic interferometry is a primary candidate for the measurement of temperature and concentration in various crystal growth experiments destined for space. The method measures refractive index changes in the experiment test cell. A refractive index change can be caused by concentration changes, temperature changes, or a combination of temperature and concentration changes. If the refractive index changes are caused by temperature and concentration changes occurring simultaneously in the experiment test cell, the contributions by the two effects cannot be separated by conventional measurement methods. By using two wavelengths, two independent interferograms can be produced from the reconstruction of the hologram. The two interferograms will be different due to dispersion properties of fluid materials. These differences provide the additional information that allows the separation of simultaneously occurring temperature and concentration gradients. There is no other technique available that can provide this type of information. The primary objectives of this effort are to experimentally verify the mathematical theory of two color holographic interferometry and to determine the practical value of this technique for space application. To achieve these objectives, the accuracy and sensitivity of the technique must be determined for geometry's and materials that are relevant to the Materials Processing in the Space program of NASA. This will be achieved through the use of a specially designed two-color holographic interferometry breadboard optical system. In addition to experiments to achieve the primary goals, the breadboard will also provide inputs to the design of an optimum space flight system.

  15. Two-color resonant filamentation in gases

    NASA Astrophysics Data System (ADS)

    Doussot, J.; Béjot, P.; Faucher, O.

    2016-07-01

    In this paper, it is shown that two-photon resonance involving a fundamental field and one of its odd harmonic strongly influences the filamentation process, i.e., the nonlinear propagation of an ultrashort and ultraintense laser field. This particular situation happens, for instance, when a 400 nm fundamental field propagates together with its third harmonic in krypton. Using three-dimensional ab initio calculations, the optical response of krypton is evaluated and the underlying nonlinear refractive indices are extracted. It is found that the resonance also exacerbates higher-order nonlinear processes. Injecting the retrieved higher-order Kerr indices in a nonlinear propagation solver, it is found that the resonance leads to an enhanced defocusing cross-phase modulation that strongly participates to the filament stabilization. This work sheds a light on the mechanism of filamentation, in particular, in the ultraviolet range, where two-color two-photon resonances are expected to occur in many atomic gases.

  16. Two color holographic interferometry for microgravity application

    NASA Technical Reports Server (NTRS)

    Trolinger, James D.; Weber, David C.

    1995-01-01

    Holographic interferometry is a primary candidate for determining temperature and concentration in crystal growth experiments designed for space. The method measures refractive index changes within the fluid of an experimental test cell resulting from temperature and/or concentration changes. When the refractive index changes are caused by simultaneous temperature and concentration changes, the contributions of the two effects cannot be separated by single wavelength interferometry. By using two wavelengths, however, two independent interferograms can provide the additional independent equation required to determine the two unknowns. There is no other technique available that provides this type of information. The primary objectives of this effort were to experimentally verify the mathematical theory of two color holographic interferometry (TCHI) and to determine the practical value of this technique for space application. In the foregoing study, the theory of TCHI has been tested experimentally over a range of interest for materials processing in space where measurements of temperature and concentration in a solution are required. New techniques were developed and applied to stretch the limits beyond what could be done with existing procedures. The study resulted in the production of one of the most advanced, enhanced sensitivity holographic interferometers in existence. The interferometric measurements made at MSFC represent what is believed to be the most accurate holographic interferometric measurements made in a fluid to date. The tests have provided an understanding of the limitations of the technique in practical use.

  17. Storage ring two-color free-electron laser

    NASA Astrophysics Data System (ADS)

    Yan, J.; Hao, H.; Li, J. Y.; Mikhailov, S. F.; Popov, V. G.; Vinokurov, N. A.; Huang, S.; Wu, J.; Günster, S.; Wu, Y. K.

    2016-07-01

    We report a systematic experimental study of a storage ring two-color free-electron laser (FEL) operating simultaneously in the infrared (IR) and ultraviolet (UV) wavelength regions. The two-color FEL lasing has been realized using a pair of dual-band high-reflectivity FEL mirrors with two different undulator configurations. We have demonstrated independent wavelength tuning in a wide range for each lasing color, as well as harmonically locked wavelength tuning when the UV lasing occurs at the second harmonic of the IR lasing. Precise power control of two-color lasing with good power stability has also been achieved. In addition, the impact of the degradation of FEL mirrors on the two-color FEL operation is reported. Furthermore, we have investigated the temporal structures of the two-color FEL beams, showing simultaneous two-color micropulses with their intensity modulations displayed as FEL macropulses.

  18. Development of a two-color FQI

    SciTech Connect

    Butcher, T.; Wei, G.

    1996-07-01

    The Flame Quality Indicator (FQI) concept was developed at Brookhaven National Laboratory as a simple device which could be used to monitor oil burner flames and indicate when a problem was starting to occur. Fault situations which could be identified by the FQI include: fouled nozzle, increased or decreased excess air, blocked air inlet or flue, and use of low quality oil. The basic concept of the FQI is quite simple. A conventional cadmium sulfide photocell is used to measure the amount of light emitted from an oil burner flame when the appliance is fully warmed-up. The measured amount of light is compared to a set point, established during burner tune-up. If the two intensities differ by more than a set range, a {open_quotes}service required{close_quotes} signal is produced. The amount of light which is emitted from an oil burner flame depends upon the amount of {open_quotes}soot{close_quotes} or carbon in the flame, the size and shape of the flame, and the flame temperature. The quality of flame is practically judged by the amount of soot which it is producing and for this reason it is necessary to eliminate effects of other parameters. Temperature is expected to be the most important of these. The FQI eliminates effects due to the chamber environment by establishing a set point for each specific appliance. The transient temperature effects are accounted for by examining the flame brightness only at a single time during the firing cycle. BNL is currently involved with the development of a two-color approach to the monitoring of flame quality. The basic concept involved is the measurement of both flame temperature and total amount of light emitted to allow a more direct estimate to be made of the amount of soot being produced and so the flame quality. The objective is to develop a more sensitive measurement which may be more universally applicable. This paper provides a summary of our approach and results to date in this project.

  19. Two-color double exposure photographic recording technique.

    PubMed

    Stricker, J

    1989-05-15

    A two-color double exposure technique is proposed for recording two close states of an object on the same photographic film. The idea is to use a two-color laser for illumination, one color for each state of the object, and a single photographic plate. After being developed, the image of each state may be observed separately. The technique is demonstrated for the deferred moire deflectometry where two closely displaced fringe patterns have to be recorded and resolved. PMID:20548749

  20. Two-color double exposure photographic recording technique

    NASA Technical Reports Server (NTRS)

    Stricker, Josef

    1989-01-01

    A two-color double exposure technique is proposed for recording two close states of an object on the same photographic film. The idea is to use a two-color laser for illumination, one color for each state of the object, and a single photographic plate. After being developed, the image of each state may be observed separately. The technique is demonstrated for the deferred moire deflectometry where two closely displaced fringe patterns have to be recorded and resolved.

  1. 15 CFR 14.15 - Metric system of measurement.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... COMMERCIAL ORGANIZATIONS Pre-Award Requirements § 14.15 Metric system of measurement. The Metric Conversion... 15 Commerce and Foreign Trade 1 2011-01-01 2011-01-01 false Metric system of measurement. 14.15... system is the preferred measurement system for U.S. trade and commerce. The Act requires each...

  2. 15 CFR 14.15 - Metric system of measurement.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... COMMERCIAL ORGANIZATIONS Pre-Award Requirements § 14.15 Metric system of measurement. The Metric Conversion... 15 Commerce and Foreign Trade 1 2012-01-01 2012-01-01 false Metric system of measurement. 14.15... system is the preferred measurement system for U.S. trade and commerce. The Act requires each...

  3. 15 CFR 14.15 - Metric system of measurement.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... COMMERCIAL ORGANIZATIONS Pre-Award Requirements § 14.15 Metric system of measurement. The Metric Conversion... 15 Commerce and Foreign Trade 1 2013-01-01 2013-01-01 false Metric system of measurement. 14.15... system is the preferred measurement system for U.S. trade and commerce. The Act requires each...

  4. 15 CFR 14.15 - Metric system of measurement.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Metric system of measurement. 14.15 Section 14.15 Commerce and Foreign Trade Office of the Secretary of Commerce UNIFORM ADMINISTRATIVE... system is the preferred measurement system for U.S. trade and commerce. The Act requires each...

  5. 15 CFR 14.15 - Metric system of measurement.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 15 Commerce and Foreign Trade 1 2014-01-01 2014-01-01 false Metric system of measurement. 14.15... COMMERCIAL ORGANIZATIONS Pre-Award Requirements § 14.15 Metric system of measurement. The Metric Conversion... system is the preferred measurement system for U.S. trade and commerce. The Act requires each...

  6. Rational choices for the wavelengths of a two color interferometer

    SciTech Connect

    Jobes, F.C.

    1995-07-01

    If in a two color interferometer for plasma density measurements, the two wavelengths are chosen to have a ratio that is a rational number, and if the signals from each of the wavelengths are multiplied in frequency by the appropriate integer of the rational number and then heterodyned together, the resultant signal will have all effects of component motion nulled out. A phase measurement of this signal will have only plasma density information in it. With CO{sub 2} lasers, it is possible to find suitable wavelength pairs which are close enough to rational numbers to produce an improvement of about 100 in density resolution, compared to standard two color interferometers.

  7. Two-Color Ultrafast Photoexcited Scanning Tunneling Microscopy

    SciTech Connect

    Camillone, N.; Dolocan, A.; Acharya, D.P.; Zahl, P.; Sutter, P.

    2011-05-26

    We report on two-color two-photon photoexcitation of a metal surface driven by ultrafast laser pulses and detected with a scanning tunneling microscope (STM) tip as a proximate anode. Results are presented for two cases: (i) where the tip is retracted from the surface far enough to prohibit tunneling, and (ii) where the tip is within tunneling range of the surface. A delay-modulation technique is implemented to isolate the two-color photoemission from concurrent one-color two-photon photoemission and provide subpicosecond time-resolved detection. When applied with the tip in tunneling range, this approach effectively isolates the two-photon photoexcited current signal from the conventional tunneling current and enables subpicosecond time-resolved detection of the photoexcited surface electrons. The advantage of the two-color approach is highlighted by comparison with the one-color case where optical interference causes thermal modulation of the STM tip length, resulting in tunneling current modulations that are orders of magnitude larger than the current due to photoexcitation of surface electrons. By completely eliminating this interference, and thereby avoiding thermal modulation of the STM tip length, the two-color approach represents an important step toward the ultimate goal of simultaneous subnanometer and subpicosecond measurements of surface electron dynamics by ultrafast-laser-excited STM.

  8. Large format two-color CMOS ROIC for SLS detectors

    NASA Astrophysics Data System (ADS)

    Simolon, Brian; Aziz, Naseem; Barskey, Steve; Hansen, Randy; Kurth, Eric; Long, John; Petronio, Susan

    2013-07-01

    The ISC0905 is a 640 × 512, large format, two-color CMOS readout integrated circuit (ROIC) designed for strained-layer superlattice (SLS) detectors. The detector interface is supported through one input pad in each 30 μm pixel. One bit in the serial control word programs the chip to automatically adjust all biases and timing to allow for the integration of either electrons or holes. This feature allows users to easily operate this ROIC with a wide variety of p-on-n or n-on-p detectors. The ROIC has been specifically designed to allow for both polarities of detectors to be placed back-to-back and to connect to the ROIC through a single input pad to obtain a two-color image. The two-color image is achieved by switching the ROIC mode between the two colors on a per frame basis. This paper will describe the interface, design and features of the ISC0905 ROIC as well as a summary of the characterization test results.

  9. Vertex Exponents of Two-Colored Extremal Ministrong Digraphs

    NASA Astrophysics Data System (ADS)

    Suwilo, Saib

    2011-06-01

    The exponent of a vertex v in a two-colored digraph D(2) is the smallest positive integer h+k such that for each vertex x in D(2) there is a walk of length h+k consisting of h red arcs and k blue arcs. Let D(2) be a primitive two-colored extremalministrong digraphon n vertices. If D(2) has one blue arc, the exponent of the vertices of D(2) lieson the interval [n2-5n+8,n2-3n+1]. If D(2) has two blue arcs, the exponent of the vertices in D(2) lies on the interval [n2-4n+4,n2-n].

  10. Design study for a two-color beta measurement system

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Design analysis of the beam splitter combined two color beta system is presented. Conventional and dichroic beam splitters are discussed. Design analysis of the beta system employing two beams with focusing at separate points is presented. Alterations and basic parameters of the two beam system are discussed. Alterations in the focus of the initial laser and the returning beams are also discussed. Heterodyne efficiencies for the on axis and off axis reflected radiation are included.

  11. Two-color QCD with chiral chemical potential

    NASA Astrophysics Data System (ADS)

    Braguta, V. V.; Goy, V. A.; Ilgenfritz, E.-M.; Kotov, A. Yu.; Molochkov, A. V.; Müller-Preussker, M.; Petersson, B.; Schreiber, A.

    2016-01-01

    The phase diagram of two-color QCD with a chiral chemical potential is studied on the lattice. The focus is on the confinement/deconfinement phase transition and the breaking/restoration of chiral symmetry. The simulations are carried out with dynamical staggered fermions without rooting. The dependence of the Polyakov loop, the chiral condensate and the corresponding susceptibilities on the chiral chemical potential and the temperature are presented.

  12. 16 CFR 14.15 - In regard to comparative advertising.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 1 2011-01-01 2011-01-01 false In regard to comparative advertising. 14.15... comparative advertising. (a) Introduction. The Commission's staff has conducted an investigation of industry trade associations and the advertising media regarding their comparative advertising policies. In...

  13. 50 CFR 14.15 - Personal baggage and household effects.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 50 Wildlife and Fisheries 1 2010-10-01 2010-10-01 false Personal baggage and household effects. 14... Designated Ports § 14.15 Personal baggage and household effects. (a) Any person may import into or export... household effects of persons moving their residence to or from the United States may be imported or...

  14. Orbital analysis of two-color laser ranging

    NASA Astrophysics Data System (ADS)

    Schillak, S. R.

    2013-12-01

    The poster presents the results of analysis of Zimmerwald SLR data for two colors 423nm and 846 nm. Two-color laser ranging were performed by Zimmerwald SLR station from August 2002 to January 2008. The results in each color were treated as two independent stations 7810 Blue and 7810 Infrared. The station positions were determined by NASA Goddard's orbital program GEODYN-II from results of LAGEOS-1 and LAGEOS-2 satellites. The NEU positions stability were equal to 3.5 mm (N), 3.2 mm (E), 16.5 mm (U) for blue and 3.2 mm (N), 2.9 mm (E), 14.6 (U) for infrared. In the period of study were 47 common monthly points for both colors. The difference between N, E, U components in blue and infrared for common points were equal to 0.8×2.0 mm, 0.4×1.9 mm and -4.8×8.7 mm respectively. The differences between Range Biases for both colors independently for LAGEOS-1 and LAGEOS-2 were equal to -5.7×8.6 mm and for -5.0×9.5 mm respectively. The same for both satellites annual wave with amplitude 10 mm was detected. This effect can to be explain by differences in atmospheric correction for each color. This same analysis for station Concepcion (7405) couldn't to be performed due to only 8 common points. In future very important should be laser ranging in two-colors 532 nm and 1064 nm for confirmation presented here results, especially that a new sensitive APD detectors for 1064 nm are now available. The atmospheric correction is critical for SLR accuracy upgrading.

  15. 14,15-Epoxyeicosa-5,8,11-trienoic Acid (14,15-EET) Surrogates: Carboxylate Modifications

    PubMed Central

    2015-01-01

    The cytochrome P450 eicosanoid 14,15-epoxyeicosa-5,8,11-trienoic acid (14,15-EET) is a powerful endogenous autacoid that has been ascribed an impressive array of physiologic functions including regulation of blood pressure. Because 14,15-EET is chemically and metabolically labile, structurally related surrogates containing epoxide bioisosteres were introduced and have become useful in vitro pharmacologic tools but are not suitable for in vivo applications. A new generation of EET mimics incorporating modifications to the carboxylate were prepared and evaluated for vasorelaxation and inhibition of soluble epoxide hydrolase (sEH). Tetrazole 19 (ED50 0.18 μM) and oxadiazole-5-thione 25 (ED50 0.36 μM) were 12- and 6-fold more potent, respectively, than 14,15-EET as vasorelaxants; on the other hand, their ability to block sEH differed substantially, i.e., 11 vs >500 nM. These data will expedite the development of potent and specific in vivo drug candidates. PMID:25119815

  16. Spinor Slow Light and Two-Color Qubits

    NASA Astrophysics Data System (ADS)

    Yu, Ite; Lee, Meng-Jung; Ruseckas, Julius; Lee, Chin-Yuan; Kudriasov, Viaceslav; Chang, Kao-Fang; Cho, Hung-Wen; Juzeliunas, Gediminas; Yu, Ite A.

    2015-05-01

    We report the first experimental demonstration of two-component or spinor slow light (SSL) using a double tripod (DT) atom-light coupling scheme. The scheme involves three atomic ground states coupled to two excited states by six light fields. The oscillation due to the interaction between the two components was observed. SSL can be used to achieve high conversion efficiencies in the sum frequency generation and is a better method than the widely-used double- Λ scheme. On the basis of the stored light, our data showed that the DT scheme behaves like the two outcomes of an interferometer enabling precision measurements of frequency detuning. Furthermore, the single-photon SSL can be considered as the qubit with the superposition state of two frequency modes or, simply, as the two-color qubit. We experimentally demonstrated a possible application of the DT scheme as quantum memory/rotator for the two-color qubit. This work opens up a new direction in the EIT/slow light research. yu@phys.nthu.edu.tw

  17. Two-color ghost imaging with enhanced angular resolving power

    SciTech Connect

    Karmakar, Sanjit; Shih, Yanhua

    2010-03-15

    This article reports an experimental demonstration on nondegenerate, two-color, biphoton ghost imaging which reproduced a ghost image with enhanced angular resolving power by means of a greater field of view compared with that of classical imaging. With the same imaging magnification, the enhanced angular resolving power and field of view compared with those of classical imaging are 1.25:1 and 1.16:1, respectively. The enhancement of angular resolving power depends on the ratio between the idler and the signal photon frequencies, and the enhancement of the field of view depends mainly on the same ratio and also on the distances of the object plane and the imaging lens from the two-photon source. This article also reports the possibility of reproducing a ghost image with the enhancement of the angular resolving power by means of a greater imaging amplification compared with that of classical imaging.

  18. Multidimensional data reconstruction for two color fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Dilipkumar, Shilpa; Mondal, Partha Pratim

    2012-12-01

    We propose an iterative data reconstruction technique specifically designed for multi-dimensional multi-color fluorescence imaging. Markov random field is employed (for modeling the multi-color image field) in conjunction with the classical maximum likelihood method. It is noted that, ill-posed nature of the inverse problem associated with multi-color fluorescence imaging forces iterative data reconstruction. Reconstruction of three-dimensional (3D) two-color images (obtained from nanobeads and cultured cell samples) show significant reduction in the background noise (improved signal-to-noise ratio) with an impressive overall improvement in the spatial resolution (≈250 nm) of the imaging system. Proposed data reconstruction technique may find immediate application in 3D in vivo and in vitro multi-color fluorescence imaging of biological specimens.

  19. Two-color beam generation based on wakefield excitation

    NASA Astrophysics Data System (ADS)

    Bettoni, S.; Prat, E.; Reiche, S.

    2016-05-01

    Several beam manipulation methods have been studied and experimentally tested to generate two-color photon beams in free electron laser facilities to accommodate the user requests. We propose to use the interaction of the beam with an oscillating longitudinal wakefield source to obtain a suitable electron beam structure. The bunch generates two subpulses with different energies and delayed in time passing through a magnetic chicane after its longitudinal phase space has been modulated by the wakefield source. According to this approach the power of the emitted radiation is not degraded compared to the monochromatic beam, and the setup in the machine is quite simple because the bunch is manipulated only in the high energy section, where it is more rigid. We present the design applied to SwissFEL. We identified the parameters and the corresponding range of tunability of the time and energy separation among the two subbunches.

  20. Two-color holography concept (T-CHI)

    NASA Technical Reports Server (NTRS)

    Vikram, C. S.; Caulfield, H. J.; Workman, G. L.; Trolinger, J. D.; Wood, C. P.; Clark, R. L.; Kathman, A. D.; Ruggiero, R. M.

    1990-01-01

    The Material Processing in the Space Program of NASA-MSFC was active in developing numerous optical techniques for the characterization of fluids in the vicinity of various materials during crystallization and/or solidification. Two-color holographic interferometry demonstrates that temperature and concentration separation in transparent (T-CHI) model systems is possible. The experiments were performed for particular (succinonitrile) systems. Several solutions are possible in Microgravity Sciences and Applications (MSA) experiments on future Shuttle missions. The theory of the T-CHI concept is evaluated. Although particular cases are used for explanations, the concepts developed will be universal. A breadboard system design is also presented for ultimate fabrication and testing of theoretical findings. New developments in holography involving optical fibers and diode lasers are also incorporated.

  1. Single bump, two-color quantum dot camera

    NASA Astrophysics Data System (ADS)

    Varley, E.; Lenz, M.; Lee, S. J.; Brown, J. S.; Ramirez, D. A.; Stintz, A.; Krishna, S.; Reisinger, Axel; Sundaram, Mani

    2007-08-01

    The authors report a two-color, colocated quantum dot based imaging system used to take multicolor images using a single focal plane array (FPA). The dots-in-a-well (DWELL) detectors consist of an active region composed of InAs quantum dots embedded in In.15Ga.85As quantum wells. DWELL samples were grown using molecular beam epitaxy and fabricated into 320×256 focal plane arrays with indium bumps. The FPA was then hybridized to an Indigo ISC9705 readout circuit and tested. Calibrated blackbody measurements at a device temperature of 77K yield midwave infrared and long wave infrared noise equivalent difference in temperature of ˜55 and 70mK.

  2. Two-color detection with charge sensitive infrared phototransistors

    SciTech Connect

    Kim, Sunmi Kajihara, Yusuke; Komiyama, Susumu; Ueda, Takeji; Satoh, Takashi

    2015-11-02

    Highly sensitive two-color detection is demonstrated at wavelengths of 9 μm and 14.5 μm by using a charge sensitive infrared phototransistor fabricated in a triple GaAs/AlGaAs quantum well (QW) crystal. Two differently thick QWs (7 nm- and 9 nm-thicknesses) serve as photosensitive floating gates for the respective wavelengths via intersubband excitation: The excitation in the QWs is sensed by a third QW, which works as a conducting source-drain channel in the photosensitive transistor. The two spectral bands of detection are shown to be controlled by front-gate biasing, providing a hint for implementing voltage tunable ultra-highly sensitive detectors.

  3. Silicon photodiode as the two-color detector

    NASA Astrophysics Data System (ADS)

    Ponomarev, D. B.; Zakharenko, V. A.

    2015-11-01

    This paper describes a silicon photodiode as the two-color photodetector. The work of one photodiode in two spectral ranges is achieved due to the changes of the spectral sensitivity of the photodiodes in the transition from photodiode mode for photovoltaic in the short circuit mode. On the basis of silicon photodiode FD-256 the layout of the spectral ratio pyrometer was assembled and the results of theoretical calculations was confirmed experimentally. The calculated dependences of the coefficient of error of the spectral ratio pyrometer from temperature reverse voltage 10 and 100 V was presented. The calculated dependence of the instrumental error and the assessment of methodological errors of the proposed photodetector spectral ratio was done. According to the results of the presented research was set the task of development photodiode detectors which change the spectral sensitivity depending on the applied voltage.

  4. Two-color vibrationally mediated photodissociation of nitric acid

    SciTech Connect

    Sinha, A.; Vander Wal, R.L.; Butler, L.J.; Crim, F.F.

    1987-08-27

    Two-color vibrationally mediated photodissociation, in which one photon excites an overtone vibration and a second photon of a different wavelength dissociates the highly vibrationally excited molecule prepared by the first photon, is a means of investigating the role of vibrational excitation in photodissociation and of obtaining vibrational overtone excitation spectra. Application of this scheme to nitric acid (HONO/sub 2/) involves exciting the third OH stretching overtone vibration (4v/sub OH/), photodissociating the vibrationally excited molecule with 355-nm light, and detecting the OH fragment using laser-induced fluorescence. These measurements show that most of the OH products are vibrationally unexcited and that about a quarter of the available energy goes into relative translation. The vibrational overtone excitation spectrum has congested P-, Q-, and R-branch rotational structure that forms a 50-cm/sup -1/-wide band.

  5. Noise in two-color electronic distance meter measurements revisited

    USGS Publications Warehouse

    Langbein, J.

    2004-01-01

    Frequent, high-precision geodetic data have temporally correlated errors. Temporal correlations directly affect both the estimate of rate and its standard error; the rate of deformation is a key product from geodetic measurements made in tectonically active areas. Various models of temporally correlated errors are developed and these provide relations between the power spectral density and the data covariance matrix. These relations are applied to two-color electronic distance meter (EDM) measurements made frequently in California over the past 15-20 years. Previous analysis indicated that these data have significant random walk error. Analysis using the noise models developed here indicates that the random walk model is valid for about 30% of the data. A second 30% of the data can be better modeled with power law noise with a spectral index between 1 and 2, while another 30% of the data can be modeled with a combination of band-pass-filtered plus random walk noise. The remaining 10% of the data can be best modeled as a combination of band-pass-filtered plus power law noise. This band-pass-filtered noise is a product of an annual cycle that leaks into adjacent frequency bands. For time spans of more than 1 year these more complex noise models indicate that the precision in rate estimates is better than that inferred by just the simpler, random walk model of noise.

  6. A relative-intensity two-color phosphor thermography system

    NASA Technical Reports Server (NTRS)

    Merski, N. Ronald

    1991-01-01

    The NASA LaRC has developed a relative-intensity two-color phosphor thermography system. This system has become a standard technique for acquiring aerothermodynamic data in LaRC Hypersonic Facilities Complex (HFC). The relative intensity theory and its application to the LaRC phosphor thermography system is discussed along with the investment casting technique which is critical to the utilization of the phosphor method for aerothermodynamic studies. Various approaches to obtaining quantitative heat transfer data using thermographic phosphors are addressed and comparisons between thin-film data and thermographic phosphor data on an orbiter-like configuration are presented. In general, data from these two techniques are in good agreement. A discussion is given on the application of phosphors to integration heat transfer data reduction techniques (the thin film method) and preliminary heat transfer data obtained on a calibration sphere using thin-film equations are presented. Finally, plans for a new phosphor system which uses target recognition software are discussed.

  7. Global Pc 5 event of November 14--15, 1979

    SciTech Connect

    Higbie, P.R.; Baker, D.N.; Zwickl, R.D.; Belian, R.D.; Asbridge, J.R.; Fennell, J.F.; Wilken, B.; Arthur, C.W.

    1982-04-01

    Large-amplitude Pc 5 waves with 7--8 min quasi-periodic variations were observed almost continuously for the 48 hours of November 14--15, 1979, by several spacecraft in or near geostationary orbit on the dayside portions of their orbits. The waves were observed as large modulations in both the electron and ion fluxes over a wide range of energies (approx.1 to 500 keV) by the spacecraft 1976--059, 1977-007, 1979-053, P78-2, and GEOS 2 and as magnetic field peak-to-peak modulations of 15--25 ..gamma.. by the P78-2 and GOES 2 and 3 magnetometers. The remarkably long persistence of these waves contrasts substantially with observations of typical flux modulation events which usually last less than 1 hour and which typically show little modulation of the > or =150 keV proton fluxes. Data taken concurrently by the ISEE spacecraft in the solar wind and outer magnetosphere indicate that the solar wind also had unusually properties. ISEE 3 measurements indicate that the solar wind velocity (approx.350 km/s) and density (approx.2 cm/sup -3/) were simultaneously very low for this period. The alpha-to-proton ratio for the solar wind plasma attained an extremely low value (<1%) early in the event. These solar wind properties imply such a much reduced dynamic pressure on the magnetosphere during this period. Consequently, the ISEE 1 and 2 spacecraft passed through the magnetopause at the uncommonly large radial distance of 18 R/sub E/ at approx.0830 local time where the typical magnetopause geocentric distance is 12 R/sub E/. The exceptional solar wind and outer magnetospheric conditions may have determined the unusual properties of the ULF event observed near geostationary orbit. Some candidate mechanisms for producing these oscillations are presented, but no definitive explanation for this event can be given at present.

  8. Widely Tunable Two-Color Free-Electron Laser on a Storage Ring.

    PubMed

    Wu, Y K; Yan, J; Hao, H; Li, J Y; Mikhailov, S F; Popov, V G; Vinokurov, N A; Huang, S; Wu, J

    2015-10-30

    With a wide wavelength tuning range, free-electron lasers (FELs) are well suited for producing simultaneous lasing at multiple wavelengths. We present the first experimental results of a novel two-color storage ring FEL. With three undulators and a pair of dual-band mirrors, the two-color FEL can lase simultaneously in infrared (IR) around 720 nm and in ultraviolet (UV) around 360 nm. We have demonstrated independent wavelength tuning in a wide range (60 nm in IR and 24 nm in UV). We have also realized two-color harmonic operation with the UV lasing tuned to the second harmonic of the IR lasing. Furthermore, we have demonstrated good power stability with two-color lasing, and good control of the power sharing between the two colors. PMID:26565470

  9. Widely Tunable Two-Color Free-Electron Laser on a Storage Ring

    NASA Astrophysics Data System (ADS)

    Wu, Y. K.; Yan, J.; Hao, H.; Li, J. Y.; Mikhailov, S. F.; Popov, V. G.; Vinokurov, N. A.; Huang, S.; Wu, J.

    2015-10-01

    With a wide wavelength tuning range, free-electron lasers (FELs) are well suited for producing simultaneous lasing at multiple wavelengths. We present the first experimental results of a novel two-color storage ring FEL. With three undulators and a pair of dual-band mirrors, the two-color FEL can lase simultaneously in infrared (IR) around 720 nm and in ultraviolet (UV) around 360 nm. We have demonstrated independent wavelength tuning in a wide range (60 nm in IR and 24 nm in UV). We have also realized two-color harmonic operation with the UV lasing tuned to the second harmonic of the IR lasing. Furthermore, we have demonstrated good power stability with two-color lasing, and good control of the power sharing between the two colors.

  10. 21 CFR 14.15 - Committees working under a contract with FDA.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Committees working under a contract with FDA. 14.15 Section 14.15 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PUBLIC HEARING BEFORE A PUBLIC ADVISORY COMMITTEE General Provisions § 14.15 Committees working under a contract with FDA. (a) FDA may...

  11. 21 CFR 14.15 - Committees working under a contract with FDA.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Committees working under a contract with FDA. 14.15 Section 14.15 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PUBLIC HEARING BEFORE A PUBLIC ADVISORY COMMITTEE General Provisions § 14.15 Committees working under a contract with FDA. (a) FDA may...

  12. Development of two color laser diagnostics for the ITER poloidal polarimeter

    SciTech Connect

    Kawahata, K.; Akiyama, T.; Tanaka, K.; Nakayama, K.; Okajima, S.

    2010-10-15

    Two color laser diagnostics using terahertz laser sources are under development for a high performance operation of the Large Helical Device and for future fusion devices such as ITER. So far, we have achieved high power laser oscillation lines simultaneously oscillating at 57.2 and 47.7 {mu}m by using a twin optically pumped CH{sub 3}OD laser, and confirmed the original function, compensation of mechanical vibration, of the two color laser interferometer. In this article, application of the two color laser diagnostics to the ITER poloidal polarimeter and recent hardware developments will be described.

  13. Propagation characteristics of two-color laser pulses in homogeneous plasma

    SciTech Connect

    Hemlata,; Saroch, Akanksha; Jha, Pallavi

    2015-11-15

    An analytical and numerical study of the evolution of two-color, sinusoidal laser pulses in cold, underdense, and homogeneous plasma has been presented. The wave equations for the radiation fields driven by linear as well as nonlinear contributions due to the two-color laser pulses have been set up. A variational technique is used to obtain the simultaneous equations describing the evolution of the laser spot size, pulse length, and chirp parameter. Numerical methods are used to graphically analyze the simultaneous evolution of these parameters due to the combined effect of the two-color laser pulses. Further, the pulse parameters are compared with those obtained for a single laser pulse. Significant focusing, compression, and enhanced positive chirp is obtained due to the combined effect of simultaneously propagating two-color pulses as compared to a single pulse propagating in plasma.

  14. Propagation characteristics of two-color laser pulses in homogeneous plasma

    NASA Astrophysics Data System (ADS)

    Hemlata, Saroch, Akanksha; Jha, Pallavi

    2015-11-01

    An analytical and numerical study of the evolution of two-color, sinusoidal laser pulses in cold, underdense, and homogeneous plasma has been presented. The wave equations for the radiation fields driven by linear as well as nonlinear contributions due to the two-color laser pulses have been set up. A variational technique is used to obtain the simultaneous equations describing the evolution of the laser spot size, pulse length, and chirp parameter. Numerical methods are used to graphically analyze the simultaneous evolution of these parameters due to the combined effect of the two-color laser pulses. Further, the pulse parameters are compared with those obtained for a single laser pulse. Significant focusing, compression, and enhanced positive chirp is obtained due to the combined effect of simultaneously propagating two-color pulses as compared to a single pulse propagating in plasma.

  15. Baryonic matter onset in two-color QCD with heavy quarks

    NASA Astrophysics Data System (ADS)

    Scior, Philipp; von Smekal, Lorenz

    2015-11-01

    We study the cold and dense regime in the phase diagram of two-color QCD with heavy quarks within a three-dimensional effective theory for Polyakov loops. This theory is derived from two-color QCD in a combined strong-coupling and hopping expansion. In particular, we study the onset of diquark density as the finite-density transition of the bosonic baryons in the two-color world. In contrast to previous studies of heavy dense QCD, our zero-temperature extrapolations are consistent with a continuous transition without binding energy. They thus provide evidence that the effective theory for heavy quarks is capable of describing the characteristic differences between diquark condensation in two-color QCD and the liquid-gas transition of nuclear matter in QCD.

  16. Two-color photorefractive properties in near-stoichiometric lithium tantalate crystals

    NASA Astrophysics Data System (ADS)

    Liu, Youwen; Kitamura, Kenji; Takekawa, Shunji; Nakamura, Masaru; Furukawa, Yasunori; Hatano, Hideki

    2004-06-01

    The two-color photorefractive properties in undoped as-grown near-stoichiometric lithium tantalate crystals were investigated, where a near-infrared laser and a cw ultraviolet beam were used for writing and gating, respectively. The key parameters in characterizing two-color photorefractive effect, light-induced absorption change, two-color sensitivity, refractive index change, readout characteristics, and dark decay were measured by changing intensities of gating and writing beams, wavelengths of gating and writing beams for the crystals with different near-stoichiometric crystal compositions, and proton concentrations. The results showed that there exists an optimal crystal composition of around 49.65% for both sensitivity and refractive index change together with moderate lifetime of small polarons. The achieved refractive index change was on the order of 10-4, and the obtained maximum sensitivity was 0.18 cm/J. The extrapolated lifetime of holograms at room temperature in the crystals without observable OH- absorption was longer than 50 yr. The measurements of UV-induced absorption change at room temperature and low temperature of 77.3 K suggested that the unintentional impurity of Fe and intrinsic defects were responsible for two-color photorefractive effect. The excellent two-color photorefractive properties of undoped as-grown near-stoichiometric lithium tantalate crystals were discussed based on this mechanism and the physical properties of lithium tantalate.

  17. Optimization of infrared two-color multicycle field synthesis for intense-isolated-attosecond-pulse generation

    SciTech Connect

    Lan Pengfei; Takahashi, Eiji J.; Midorikawa, Katsumi

    2010-11-15

    We present the optimization of the two-color synthesis method for generating an intense isolated attosecond pulse (IAP) in the multicycle regime. By mixing an infrared assistant pulse with a Ti:sapphire main pulse, we show that an IAP can be produced using a multicycle two-color pulse with a duration longer than 30 fs. We also discuss the influence of the carrier-envelope phase (CEP) and the relative intensity on the generation of IAPs. By optimizing the wavelength of the assistant field, IAP generation becomes insensitive to the CEP slip. Therefore, the optimized two-color method enables us to relax the requirements of pulse duration and easily produce the IAP with a conventional multicycle laser pulse. In addition, it enables us to markedly suppress the ionization of the harmonic medium. This is a major advantage for efficiently generating intense IAPs from a neutral medium by applying the appropriate phase-matching and energy-scaling techniques.

  18. Optimization of infrared two-color multicycle field synthesis for intense-isolated-attosecond-pulse generation

    NASA Astrophysics Data System (ADS)

    Lan, Pengfei; Takahashi, Eiji J.; Midorikawa, Katsumi

    2010-11-01

    We present the optimization of the two-color synthesis method for generating an intense isolated attosecond pulse (IAP) in the multicycle regime. By mixing an infrared assistant pulse with a Ti:sapphire main pulse, we show that an IAP can be produced using a multicycle two-color pulse with a duration longer than 30 fs. We also discuss the influence of the carrier-envelope phase (CEP) and the relative intensity on the generation of IAPs. By optimizing the wavelength of the assistant field, IAP generation becomes insensitive to the CEP slip. Therefore, the optimized two-color method enables us to relax the requirements of pulse duration and easily produce the IAP with a conventional multicycle laser pulse. In addition, it enables us to markedly suppress the ionization of the harmonic medium. This is a major advantage for efficiently generating intense IAPs from a neutral medium by applying the appropriate phase-matching and energy-scaling techniques.

  19. Isolated attosecond pulse generation with the chirped two-color laser field

    NASA Astrophysics Data System (ADS)

    Tai, Huiqin; Li, Fang; Wang, Zhe

    2016-07-01

    We propose a scheme to generate isolated attosecond pulse using a linearly chirped two-color laser field, which includes a fundamental laser field and a weak infrared control laser field in the multicycle regime. The fundamental laser field consists of one linearly up-chirped and one linearly down-chirped pulses. The control pulse is chirped free. We compare the attosecond pulse generated in the chirped two-color field and the chirp-free field. It is found that an IAP can be generated even without carrier envelop phase stabilization in the chirped two-color laser field with a duration of 40 fs. We also discuss the influence of the relative intensity, relative phase, time delay, and chirping parameters on the generation of IAPs.

  20. Two-color-laser-driven direct electron acceleration in infinite vacuum.

    PubMed

    Wong, Liang Jie; Kärtner, Franz X

    2011-03-15

    We propose a direct electron acceleration scheme that uses a two-color pulsed radially polarized laser beam. The two-color scheme achieves electron acceleration exceeding 90% of the theoretical energy gain limit, over twice of what is possible with a one-color pulsed beam of equal total energy and pulse duration. The scheme succeeds by exploiting the Gouy phase shift to cause an acceleration-favoring interference of fields only as the electron enters its effectively final accelerating cycle. Optimization conditions and power scaling characteristics are discussed. PMID:21403741

  1. Seeded free electron laser operating with two colors: Comments on experimental results

    NASA Astrophysics Data System (ADS)

    Carpanese, M.; Ciocci, F.; Dattoli, G.; Petralia, A.; Petrillo, V.; Torre, A.

    2016-05-01

    Free electron lasers operating with two colors are promising devices for applications. The relevant modelization has provided a good understanding of the underlying physics. In this paper we present an analysis of the experimental results obtained at SPARC_LAB concerning seeded two-colors free electron laser (FEL) operation. The use of an ad hoc developed semi-analytical model based on the small-signal FEL integral equation reproduces most of the observed phenomenology. The paper discusses the reliability of the proposed method, the range of validity and its possible improvement.

  2. Energy exchange between modes in a multimode two-color quantum dot laser with optical feedback.

    PubMed

    Virte, Martin; Pawlus, Robert; Sciamanna, Marc; Panajotov, Krassimir; Breuer, Stefan

    2016-07-15

    We investigate experimentally and theoretically the multimode dynamics of a two-color quantum dot laser subject to time-delayed optical feedback. We unveil energy exchanges between the longitudinal modes of the excited state triggered by variations of the feedback phase, and observe that the modal competition between longitudinal modes appears independently within the ground state and excited state emission. These features are accurately reproduced with a quantum dot laser model extended to take into account multiple modes for both ground and excited states. Finally, we discuss the significant impact of such behavior on feedback-based control of two-color quantum dot lasers. PMID:27420496

  3. Aggregation-induced emission molecules in layered matrices for two-color luminescence films.

    PubMed

    Guan, Weijiang; Lu, Jun; Zhou, Wenjuan; Lu, Chao

    2014-10-14

    We fabricated two-color luminescence ultrathin films (UTFs) composed of the layered double hydroxide host-aggregation-induced emission guests by LBL assembly. The fabricated UTFs were simple, tunable, controllable and highly luminescent. Moreover, reversible thermochromic luminescence further exhibited their potential in practical applications. PMID:25154856

  4. Origin of Two-Color Iridescence in Rock Dove’s Feather

    NASA Astrophysics Data System (ADS)

    Yoshioka, Shinya; Nakamura, Eri; Kinoshita, Shuichi

    2007-01-01

    Iridescence is observed in various kinds of animals that utilize optical interference phenomenon of microstructures to produce their brilliant colors. It appears according to the interference condition that relates the wavelength of the reflected light with the angle of view or incidence. However, the iridescence of the neck feather of rock dove looks very peculiar; the color change is limited only in two colors, green and purple, and the change occurs very suddenly by only slightly shifting the viewing angle. We show that this two-color iridescence originates from the surprisingly simple physical mechanism—thin-layer interference. The peculiarity lies in the fact that the higher-order interference condition is satisfied. This causes the sophisticated correspondence in the spectral line shape between the reflectance and the visual color sensitivities of human eye, and results in the two-color nature of the iridescence. It is also suggested that the rock dove’s vision perceives this two-color iridescence as a tool for visual signaling among rock doves.

  5. Assessing probe-specific dye and slide biases in two-color microarray data

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A primary reason for using two-color microarrays is that the use of two samples labeled with different dyes on the same slide and that bind to probes on the same spot is supposed to adjust for many factors that introduce noise and errors into the analysis. Most users assume that any differences bet...

  6. Effects of a static electric field on two-color photoassociation between different atoms

    SciTech Connect

    Chakraborty, Debashree; Deb, Bimalendu

    2014-01-15

    We study non-perturbative effects of a static electric field on two-color photoassociation of different atoms. A static electric field induces anisotropy in scattering between two different atoms and hybridizes field-free rotational states of heteronuclear dimers or polar molecules. In a previous paper [D. Chakraborty et al., J. Phys. B 44, 095201 (2011)], the effects of a static electric field on one-color photoassociation between different atoms has been described through field-modified ground-state scattering states, neglecting electric field effects on heteronuclear diatomic bound states. To study the effects of a static electric field on heteronuclear bound states, and the resulting influence on Raman-type two-color photoassociation between different atoms in the presence of a static electric field, we develop a non-perturbative numerical method to calculate static electric field-dressed heteronuclear bound states. We show that the static electric field induced scattering anisotropy as well as hybridization of rotational states strongly influence two-color photoassociation spectra, leading to significant enhancement in PA rate and large shift. In particular, for static electric field strengths of a few hundred kV/cm, two-color PA rate involving high-lying bound states in electronic ground-state increases by several orders of magnitude even in the weak photoassociative coupling regime.

  7. Two-color short-pulse laser altimeter measurements of ocean surface backscatter.

    PubMed

    Abshire, J B; McGarry, J F

    1987-04-01

    The timing and correlation properties of pulsed laser backscatter from the ocean surface have been measured with a two-color short-pulse laser altimeter. The Nd: YAG laser transmitted 70-and 35-ps wide pulses simultaneously at 532 and 355 nm at nadir, and the time-resolved returns were recorded by a receiver with 800-ps response time. The time-resolved backscatter measured at both 330- and 1291-m altitudes showed little pulse broadening due to the submeter laser spot size. The differential delay of the 355- and 532-nm backscattered waveforms were measured with a rms error of ~75 ps. The change in aircraft altitudes also permitted the change in atmospheric pressure to be estimated by using the two-color technique. PMID:20454319

  8. Dynamically induced two-color nonreciprocity in a tripod system of a moving atomic lattice

    NASA Astrophysics Data System (ADS)

    Yang, Liu; Zhang, Yan; Yan, Xiao-Bo; Sheng, Ying; Cui, Cui-Li; Wu, Jin-Hui

    2015-11-01

    We study the two-color nonreciprocal effects of transmission and reflection in cold atoms driven into the tripod configuration and confined in a moving optical lattice. Our numerical results show that a very high contrast of the forward-backward transmission up to around 92% (reflection up to around 85%) is observable near the sharp edges of two tunable photonic band gaps at lattice speeds of several meters per second. Such two-color optical nonreciprocity is attained in fact by breaking the time-reversal symmetry with asymmetric Doppler shifts and can be dynamically manipulated by varying the driving and coupling field detunings, the probe pulse length, the atomic lattice velocity, etc.

  9. Simulation of Intense Isolated Attosecond Pulse Generation with a Two-color Laser Field

    NASA Astrophysics Data System (ADS)

    Eilanlou, Abdolreza Amani; Ishikawa, Kenichi L.; Nabekawa, Yasuo; Takahashi, Hiroyuki; Midorikawa, Katsumi

    A numerical analysis by solving the time-dependent Schrödinger equation on a neon atom within the single-active electron approximation shows that a two-color laser field synthesized from a sub-12-fs fundamental field and a detuned second harmonic field with a wavelength shorter than 380nm is suitable for generating an intense isolated attosecond pulse (IAP). We have also investigated the effects of carrier-envelope phase variation on the obtained IAP and have compared the results to those obtained from a 5-fs fundamental field alone with the same peak field amplitude to show that a more intense IAP can be generated by the two-color laser field which is useful for nonlinear experiments in the extreme ultraviolet spectral range.

  10. Design of 128×128 two-color IRFPA readout circuit

    NASA Astrophysics Data System (ADS)

    Guan, Yu; Wang, Jinchun; Ma, Dejun

    2015-10-01

    Based on the P-N-N-P type two-color infrared focal plane array( FPA) detector structure and its equivalent circuit, the principles and realization ways of a kind of 128×128 two-color infrared focal plane readout integrated circuit( ROIC) with successively integrating and simultaneously reading out have been proposed. The cell circuit using the direct injection (DI) structure as the input stage will acquire the larger integrating capacitors. This structure meets the demand that there are two independent signal channels for both the middle and short wavelength infrareds in a cell circuit. The simulation results show that the circuit meets the predetermined design requirements, the integrating time is adjustable, the readout rate is faster than or equal to 5 MHz, the linearity of the output voltages of MW and SW reach above 99%, the power dissipation is about 68 mW.

  11. Two-color mid-infrared thermometer with a hollow glass optical fiber

    SciTech Connect

    Small, W. IV; Celliers, P.M.; Da Silva, L.B.; Matthews, D.L.; Soltz, B.A.

    1998-10-01

    We have developed a low-temperature optical-fiber-based two-color infrared thermometer. A single 700-{mu}m-bore hollow glass optical fiber collects and transmits radiation that is then modulated and split into two paths by a reflective optical chopper. Two different thermoelectrically cooled mid-infrared HgCdZnTe photoconductors monitor the chopped signals that are recovered with lock-in amplification. With the two previously obtained blackbody calibration equations, a computer algorithm calculates the true temperature and emissivity of a target in real time, taking into account reflection of the ambient radiation field from the target surface. The small numerical aperture of the hollow glass fiber and the fast response of the detectors, together with the two-color principle, permit high spatial and temporal resolution while allowing the user to dynamically alter the fiber-to-target distance. {copyright} 1998 Optical Society of America

  12. Refractive properties of TGS aqueous solution for two-color interferometry

    NASA Technical Reports Server (NTRS)

    Vikram, Chandra S.; Witherow, William K.; Trolinger, James D.

    1991-01-01

    Using Cauchy's equation and previously available data, the refractive index versus wavelength relationship for triglycine sulphate aqueous solution has been determined. The variation of the index as a function of the temperature and of the concentration is then obtained using the Murphy-Alpert and the Lorentz-Lorenz relationships respectively. These refractive properties should be useful in relevant crystal growth experiments using two-color holographic and other interferometric diagnostic techniques.

  13. Two-color multiphoton ionization of diazabicyclooctane in a supersonic free jet

    NASA Astrophysics Data System (ADS)

    Fujii, Masaaki; Ebata, Takayuki; Mikami, Naohiko; Ito, Mitsuo

    1983-11-01

    Two-color multiphoton ionization (MPI) spectroscopy has been applied for diazabicyclooctane (DABCO) in a supersonic free jet. The MPI spectra due to transitions from the various vibronic levels of the S 1 (3s Rydberg) state which were excited by the first laser revealed the high Rydberg states above the adiabatic ionization potential. The ionization process and the vibrational potential of the ion are discussed.

  14. Critical needs of fringe-order accuracies in two-color holographic interferometry

    NASA Technical Reports Server (NTRS)

    Vikram, C. S.; Witherow, W. K.

    1992-01-01

    Requirements for the fringe order accuracy in two-color holographic interferometry are discussed with reference to crystal growth. A simple test cell (rectangular parallelepiped) containing a fluid is considered. The temperature and concentration variations are related to the fringe orders from the two interference patterns, and the uncertainties in the fringe orders are related to errors in the temperature and concentration determination. The formulation developed here is applied to the particular case of an aqueous solution of triglycerine sulfate as an example.

  15. Development of a new two color far infrared laser interferometer for future fusion devices

    SciTech Connect

    Kawahata, K.; Tanaka, K.; Tokuzawa, T.; Akiyama, T.; Ito, Y.; Okajima, S.; Nakayama, K.; Wylde, R.J.

    2004-10-01

    A new two color far infrared (FIR) laser interferometer under development for future fusion devices will be presented. The laser wavelength is optimized from the consideration of the beam refraction effect due to plasma density gradient and signal-to-noise ratio for an expected phase shift due to plasmas. Laser lines of 57.2 and 47.6 {mu}m are found to be suitable for the applications to high performance plasmas of Large Helical Device and future fusion devices such as the International Thermonuclear Experimental Reactor. The output power of 57.2 {mu}m CH{sub 3}OD laser is estimated to be {approx}1.6 W, which is the highest laser power in the FIR wavelength regime. The optical configuration of a new interferometer system using two colors will be proposed. In the system, one detector simultaneously detects the beat signals of the 57.2 and 47.6 {mu}m laser lines, and each interference signal can be separated electronically (1 MHz for 57.2 {mu}m and 0.84 MHz expected for 47.6 {mu}m). Mechanical vibration can be compensated by using the two color interferometer. The present status of the development of the system is also presented.

  16. Two-color high-harmonic generation in plasmas: efficiency dependence on the generating particle properties.

    PubMed

    Emelina, Anna S; Emelin, Mikhail Yu; Ganeev, Rashid A; Suzuki, Masayuki; Kuroda, Hiroto; Strelkov, Vasily V

    2016-06-27

    The high-order harmonic generation (HHG) in silver, gold, and zinc plasma plumes irradiated by orthogonally polarized two-color field is studied theoretically and experimentally. We find an increase of the HHG efficiency in comparison with the single-color case, which essentially depends on the plasma species and harmonic order. An increase of more than an order of magnitude is observed for silver plasma, whereas for gold and zinc it is lower; these results are reproduced in our calculations that include both propagation and microscopic response studies. We show that the widely used theoretical approach assuming the 1s ground state of the generating particle fails to reproduce the experimental results; the agreement is achieved in our theory using the actual quantum numbers of the outer electron of the generating particles. Moreover, our theoretical studies highlight the redistribution of the electronic density in the continuum wave packet as an important aspect of the HHG enhancement in the two-color orthogonally polarized fields with comparable intensities: in the single-color field the electronic trajectories with almost zero return energy are the most populated ones; in the two-color case the total field maximum can be shifted in time so that the trajectories with high return energies (in particular, the cut-off trajectory) become the most populated ones. PMID:27410560

  17. Two-color mixing for classifying agricultural products for safety and quality

    NASA Astrophysics Data System (ADS)

    Ding, Fujian; Chen, Yud-Ren; Chao, Kuanglin; Chan, Diane E.

    2006-02-01

    We show that the chromaticness of the visual signal that results from the two-color mixing achieved through an optically enhanced binocular device is directly related to the band ratio of light intensity at the two selected wavebands. A technique that implements the band-ratio criterion in a visual device by using two-color mixing is presented here. The device will allow inspectors to identify targets visually in accordance with a two-wavelength band ratio. It is a method of inspection by human vision assisted by an optical device, which offers greater flexibility and better cost savings than a multispectral machine vision system that implements the band-ratio criterion. With proper selection of the two narrow wavebands, discrimination by chromaticness that is directly related to the band ratio can work well. An example application of this technique for the inspection of carcasses chickens of afficted with various diseases is given. An optimal pair of wavelengths of 454 and 578 nm was selected to optimize differences in saturation and hue in CIE LUV color space among different types of target. Another example application, for the detection of chilling injury in cucumbers, is given, here the selected wavelength pair was 504 and 652 nm. The novel two-color mixing technique for visual inspection can be included in visual devices for various applications, ranging from target detection to food safety inspection.

  18. Two-Color STED Microscopy of Living Synapses Using A Single Laser-Beam Pair

    PubMed Central

    Tønnesen, Jan; Nadrigny, Fabien; Willig, Katrin I.; Wedlich-Söldner, Roland; Nägerl, U. Valentin

    2011-01-01

    The advent of superresolution microscopy has opened up new research opportunities into dynamic processes at the nanoscale inside living biological specimens. This is particularly true for synapses, which are very small, highly dynamic, and embedded in brain tissue. Stimulated emission depletion (STED) microscopy, a recently developed laser-scanning technique, has been shown to be well suited for imaging living synapses in brain slices using yellow fluorescent protein as a single label. However, it would be highly desirable to be able to image presynaptic boutons and postsynaptic spines, which together form synapses, using two different fluorophores. As STED microscopy uses separate laser beams for fluorescence excitation and quenching, incorporation of multicolor imaging for STED is more difficult than for conventional light microscopy. Although two-color schemes exist for STED microscopy, these approaches have several drawbacks due to their complexity, cost, and incompatibility with common labeling strategies and fluorophores. Therefore, we set out to develop a straightforward method for two-color STED microscopy that permits the use of popular green-yellow fluorescent labels such as green fluorescent protein, yellow fluorescent protein, Alexa Fluor 488, and calcein green. Our new (to our knowledge) method is based on a single-excitation/STED laser-beam pair to simultaneously excite and quench pairs of these fluorophores, whose signals can be separated by spectral detection and linear unmixing. We illustrate the potential of this approach by two-color superresolution time-lapse imaging of axonal boutons and dendritic spines in living organotypic brain slices. PMID:22098754

  19. 14,15-EET promotes mitochondrial biogenesis and protects cortical neurons against oxygen/glucose deprivation-induced apoptosis

    SciTech Connect

    Wang, Lai; Chen, Man; Yuan, Lin; Xiang, Yuting; Zheng, Ruimao; Zhu, Shigong

    2014-07-18

    Highlights: • 14,15-EET inhibits OGD-induced apoptosis in cortical neurons. • Mitochondrial biogenesis of cortical neurons is promoted by 14,15-EET. • 14,15-EET preserves mitochondrial function of cortical neurons under OGD. • CREB mediates effect of 14,15-EET on mitochondrial biogenesis and function. - Abstract: 14,15-Epoxyeicosatrienoic acid (14,15-EET), a metabolite of arachidonic acid, is enriched in the brain cortex and exerts protective effect against neuronal apoptosis induced by ischemia/reperfusion. Although apoptosis has been well recognized to be closely associated with mitochondrial biogenesis and function, it is still unclear whether the neuroprotective effect of 14,15-EET is mediated by promotion of mitochondrial biogenesis and function in cortical neurons under the condition of oxygen–glucose deprivation (OGD). In this study, we found that 14,15-EET improved cell viability and inhibited apoptosis of cortical neurons. 14,15-EET significantly increased the mitochondrial mass and the ratio of mitochondrial DNA to nuclear DNA. Key makers of mitochondrial biogenesis, peroxisome proliferator activator receptor gamma-coactivator 1 alpha (PGC-1α), nuclear respiratory factor 1 (NRF-1) and mitochondrial transcription factor A (TFAM), were elevated at both mRNA and protein levels in the cortical neurons treated with 14,15-EET. Moreover, 14,15-EET markedly attenuated the decline of mitochondrial membrane potential, reduced ROS, while increased ATP synthesis. Knockdown of cAMP-response element binding protein (CREB) by siRNA blunted the up-regulation of PGC-1α and NRF-1 stimulated by 14,15-EET, and consequently abolished the neuroprotective effect of 14,15-EET. Our results indicate that 14,15-EET protects neurons from OGD-induced apoptosis by promoting mitochondrial biogenesis and function through CREB mediated activation of PGC-1α and NRF-1.

  20. The t(14,15) in Mouse Strain CBA/CaH-T(14;15)6Ca/J Causes a Break in the ADAMTS12 Gene

    PubMed Central

    Acar-Perk, Bengi; Bräutigam, Karen; Grunewald, Regina; Schmutzler, Andreas; Schem, Christian; Arnold, Norbert K; Jonat, Walter; Weimer, Jörg

    2010-01-01

    The mouse strain CBA/CaH-T(14;15)6Ca/J carries a homozygous balanced reciprocal translocation between mouse chromosomes 14 and 15, but the break points of this translocation have not previously been examined in detail. Using fluorescent in situ hybridization, we assigned the break point in 14qE3 to a 200-kb region devoid of any known gene. We similarly defined the break point in 15qA1 to a 27-kb region containing involving ADAMTS12. The chromosomal break likely is between exons 2 and 3 of ADAMTS12. This gene encodes a disintegrin and metalloproteinase with thrombospondin motifs, and this product plays crucial roles in both vascularization and cancer progression and has been implicated in the development of arthritis. The CBA/CaH-T(14;15)6Ca/J mouse strain likely is a suitable model for further examination of the influences of defective ADAMTS12 in various pathologic processes. PMID:20412686

  1. Proceedings: National Conference on Bilingual Education (Austin, Texas, April 14-15, 1972).

    ERIC Educational Resources Information Center

    Dissemination and Assessment Center for Bilingual Education, Austin, TX.

    Goals of the National Conference on Bilingual Education, held on April 14-15, 1972 in Austin, Texas, were to emphasize bilingual education interaction at the national level using outstanding consultants from throughout the United States and to exchange ideas among educators in existing programs. The conference was also organized to give bilingual…

  2. Magnetic Field Mental Representations of 14-15 Years Old Students

    ERIC Educational Resources Information Center

    Ravanis, Konstantinos; Pantidos, Panagiotis; Vitoratos, Evangelos

    2009-01-01

    Children's mental representations about physical concepts and phenomena play a vital role in the learning process. This is confirmed by the data derived from relevant researches which demonstrate that the students formulate incompatible ideas compared with the scientific ones. In this research we investigate the representations of 14-15 years…

  3. Excitation of two-colored temporal solitons in a segmented quasi-phase-matching structure.

    PubMed

    Zeng, Xianglong; Ashihara, Satoshi; Wang, Zijie; Wang, Tingyun; Chen, Yuping; Cha, Myoungsik

    2009-09-14

    We conducted a numerical study on the excitation of a two-colored temporal soliton in a segmented quasi-phase-matching (QPM) structure. The device has three parts: a periodic QPM grating for second-harmonic generation, a single domain for phase shift, and a periodic QPM grating for soliton evolution. The second harmonic pulse generated in the first grating works as a seed in the cascaded up-and-down conversions in the second grating. The numerical results showed that the second harmonic seeding enables the excitation of soliton pulses with an improved spatio-temporal intensity profile in a broad bandwidth of the wave-vector mismatch. PMID:19770904

  4. Asymmetric photoelectron momentum distribution driven by two-color XUV fields

    NASA Astrophysics Data System (ADS)

    Wu, Wan-Yang; He, Feng

    2016-02-01

    The photoionization of He+ in two-color XUV fields is studied by numerically solving the time-dependent Schrödinger equation. He+ may be ionized by directly absorbing one high-energetic photon or by absorbing two photons sequentially by mediating an excited state. The interference of these two pathways results in either enhancement or suppression of photoionization, depending on the propagating direction of the photoelectron and the relative phase of two pulses. The two-pathway interference also induces the split of photoelectron momenta. This study shows that the participation of intermediate states may substantially change photoionization processes.

  5. Control of the polarization of attosecond pulses using a two-color field

    NASA Astrophysics Data System (ADS)

    Ruiz, Camilo; Hoffmann, David J.; Torres, Ricardo; Chipperfield, Luke E.; Marangos, Jonathan P.

    2009-11-01

    Control over the polarization of an attosecond pulse train (APT) is demonstrated theoretically using orthogonally polarized two-color fields. The carrier envelope phase of the two pulses is used as a control parameter to generate both an APT with linear polarization in two nearly perpendicular planes or a train of elliptically polarized pulses of alternating helicity. By using few-cycle driving laser fields an isolated attosecond pulse with elliptical polarization is shown to be generated after selecting the cut-off region of the harmonic spectrum. The control mechanism is explained in terms of classical trajectories.

  6. Enhanced attosecond bursts of relativistic high-order harmonics driven by two-color fields.

    PubMed

    Edwards, Matthew R; Platonenko, Victor T; Mikhailova, Julia M

    2014-12-15

    We study the generation of attosecond x-ray and ultraviolet pulses from relativistically driven overdense plasma targets with two-color incident light. Particle-in-cell simulations show that significant improvement in pulse intensity and isolation is achievable with appropriate laser and plasma parameters. Conversion of 5% of incident laser energy to its second harmonic can enhance the intensity of generated attosecond pulses by an order of magnitude. This approach allows the generation of higher attosecond pulse intensities with existing experimental laser technology and offers a powerful tool for the analysis of the dynamics of relativistic laser-plasma interaction. PMID:25503006

  7. Wavelength scaling of efficient high-order harmonic generation by two-color infrared laser fields

    SciTech Connect

    Lan Pengfei; Takahashi, Eiji J.; Midorikawa, Katsumi

    2010-06-15

    We theoretically investigate and demonstrate a better wavelength scaling of harmonic yield in a two-color infrared field. By mixing a Ti:sapphire assistant field with the infrared driving field, we show that high harmonic generation is enhanced and the harmonic yield scales as {lambda}{sup -3}-{lambda}{sup -4} in the plateau region, which falls more slowly as the increase of the driving laser wavelength {lambda} compared with {lambda}{sup -5}-{lambda}{sup -6} in a one-color infrared field.

  8. Fragmentation dynamics of noble gas dimers in two-color intense laser fields

    NASA Astrophysics Data System (ADS)

    Magrakvelidze, M.; Wu, J.; Doerner, R.; Thumm, U.

    2013-05-01

    We studied the dissociation dynamics of noble gas dimer ions in two-color infrared intense laser fields by analyzing their fragment-kinetic-energy-release spectra as a function of the pump-probe delay. Our calculations predict a striking ``delay gap'' in the kinetic-energy-spectra for all noble gas dimers that was so far only measured for the Ar2 dimer. We identify this phenomenon as a frustrated dissociation mechanism. This mechanism requests different pump- and probe-pulse wavelengths and involves the pump pulse to both, singly ionize the neutral dimers and dipole-couple adiabatic states in the dimer ion. Supported by the US NSF and DOE.

  9. Two-Color Single Hybrid Plasmonic Nanoemitters with Real Time Switchable Dominant Emission Wavelength.

    PubMed

    Zhou, Xuan; Wenger, Jérémie; Viscomi, Francesco N; Le Cunff, Loïc; Béal, Jérémie; Kochtcheev, Serguei; Yang, Xuyong; Wiederrecht, Gary P; Colas des Francs, Gérard; Bisht, Anu Singh; Jradi, Safi; Caputo, Roberto; Demir, Hilmi Volkan; Schaller, Richard D; Plain, Jérôme; Vial, Alexandre; Sun, Xiao Wei; Bachelot, Renaud

    2015-11-11

    We demonstrate two-color nanoemitters that enable the selection of the dominant emitting wavelength by varying the polarization of excitation light. The nanoemitters were fabricated via surface plasmon-triggered two-photon polymerization. By using two polymerizable solutions with different quantum dots, emitters of different colors can be positioned selectively in different orientations in the close vicinity of the metal nanoparticles. The dominant emission wavelength of the metal/polymer anisotropic hybrid nanoemitter thus can be selected by altering the incident polarization. PMID:26437118

  10. Two-color RESOLFT nanoscopy with green and red fluorescent photochromic proteins.

    PubMed

    Lavoie-Cardinal, Flavie; Jensen, Nickels A; Westphal, Volker; Stiel, Andre C; Chmyrov, Andriy; Bierwagen, Jakob; Testa, Ilaria; Jakobs, Stefan; Hell, Stefan W

    2014-03-17

    Up to now, all demonstrations of reversible saturable optical fluorescence transitions (RESOLFT) superresolution microscopy of living cells have relied on the use of reversibly switchable fluorescent proteins (RSFP) emitting in the green spectral range. Here we show RESOLFT imaging with rsCherryRev1.4, a new red-emitting RSFP enabling a spatial resolution up to four times higher than the diffraction barrier. By co-expressing green and red RSFPs in living cells we demonstrate two-color RESOLFT imaging both for single ("donut") beam scanning and for parallelized versions of RESOLFT nanoscopy where an array of >23,000 "donut-like" minima are scanned simultaneously. PMID:24449030

  11. Two Color FEL Driven by a Comb-like Electron Beam Distribution

    NASA Astrophysics Data System (ADS)

    Chiadroni, E.; Anania, M. P.; Artioli, M.; Bacci, A.; Bellaveglia, M.; Cianchi, A.; Ciocci, F.; Dattoli, G.; Di Giovenale, D.; Di Pirro, G.; Ferrario, M.; Gatti, G.; Giannessi, L.; Mostacci, A.; Musumeci, P.; Palumbo, L.; Petralia, A.; Petrillo, V.; Pompili, R.; Ronsivalle, C.; Rossi, A. R.; Vaccarezza, C.; Villa, F.

    We discuss a new method for the production of trains of FEL radiation pulses based on the FEL emission driven by a comb-like electron beam. In addition, we present recent experimental results on the two color FEL emission as generated at the SPARC_LAB facility: a train of two short (<200 fs) electron bunches, almost overlapped in time, with a comb-like energy distribution, has been injected in the undulator, giving rise to FEL pulses at two characteristic frequencies with multi-peaked time structure. This scheme shows also the versatility of the SPARC photo-injector to generate and manipulate such energy and time distributions.

  12. Dynamics of Strong-Field Double Ionization in Two-Color Counterrotating Fields

    NASA Astrophysics Data System (ADS)

    Chaloupka, Jan L.; Hickstein, Daniel D.

    2016-04-01

    The double ionization of helium in bichromatic, circularly polarized intense laser fields is analyzed with a classical ensemble approach. It is found that counterrotating fields produce significant nonsequential double-ion yield and drive novel ionization dynamics. It is shown that distinct pathways to ionization can be modified by altering the relative intensities of the two colors, allowing for unique control of strong-field processes. Electrons are observed to return to the ion at different angles from the angle of ionization, opening new possibilities for probing electronic and molecular structure on the ultrafast time scale.

  13. Simulation study of wakefield generation by two color laser pulses propagating in homogeneous plasma

    SciTech Connect

    Kumar Mishra, Rohit; Saroch, Akanksha; Jha, Pallavi

    2013-09-15

    This paper deals with a two-dimensional simulation of electric wakefields generated by two color laser pulses propagating in homogeneous plasma, using VORPAL simulation code. The laser pulses are assumed to have a frequency difference equal to the plasma frequency. Simulation studies are performed for two similarly as well as oppositely polarized laser pulses and the respective amplitudes of the generated longitudinal wakefields for the two cases are compared. Enhancement of wake amplitude for the latter case is reported. This simulation study validates the analytical results presented by Jha et al.[Phys. Plasmas 20, 053102 (2013)].

  14. Dynamics of Strong-Field Double Ionization in Two-Color Counterrotating Fields.

    PubMed

    Chaloupka, Jan L; Hickstein, Daniel D

    2016-04-01

    The double ionization of helium in bichromatic, circularly polarized intense laser fields is analyzed with a classical ensemble approach. It is found that counterrotating fields produce significant nonsequential double-ion yield and drive novel ionization dynamics. It is shown that distinct pathways to ionization can be modified by altering the relative intensities of the two colors, allowing for unique control of strong-field processes. Electrons are observed to return to the ion at different angles from the angle of ionization, opening new possibilities for probing electronic and molecular structure on the ultrafast time scale. PMID:27104705

  15. Generation of an isolated few-attosecond pulse in optimized inhomogeneous two-color fields

    NASA Astrophysics Data System (ADS)

    Chou, Yi; Li, Peng-Cheng; Ho, Tak-San; Chu, Shih-I.

    2015-08-01

    We present a numerical study for optimization of ultrabroad supercontinuum spectrum by controlling the waveforms of laser fields, with the ultimate goal to generate isolated ultrashort attosecond pulses. Specifically, we extend a derivative-free nonconvex optimization algorithm for maximization of the supercontinnum power spectrum near the high-order harmonic generation (HHG) cutoff. It is found that optimally shaped inhomogeneous two-color mid-infrared laser fields can greatly enhance and extend the high-order harmonic generation plateau. Wavelet time-frequency analysis and classical simulations show that the superposition of resulting hydrogen HHG supercontinuum effectively gives rise to a robust isolated 5-as pulse.

  16. Two-color planar laser-induced fluorescence thermometry in aqueous solutions

    SciTech Connect

    Robinson, G. Andrew; Lucht, Robert P.; Laurendeau, Normand M

    2008-05-20

    We demonstrate a two-color planar laser-induced fluorescence technique for obtaining two-dimensional temperature images in water. For this method, a pulsed Nd:YAG laser at 532 nm excites a solution of temperature-sensitive rhodamine 560 and temperature-insensitive sulforhodamine 640. The resulting emissions are optically separated through filters and detected via a charged-couple device (CCD) camera system. A ratio of the two images yields temperature images independent of incident irradiance. An uncertainty in temperature of {+-}1.4 deg. C is established at the 95% confidence interval.

  17. Terahertz emission from a two-color plasma filament in a slot waveguide

    SciTech Connect

    Dietze, D.; Unterrainer, K.; Darmo, J.

    2012-02-27

    Terahertz emission in forward direction from a long two-color filament placed in the center of a slot waveguide is reported. The waveguide improves the collection and imaging of the generated THz radiation. By tuning the plate separation and position of the waveguide along the filament axis, the emitted mode can be matched to the collection optics. We achieved an increase of the detected electric field by 40% and of the THz pulse energy by four times compared to the case without waveguide.

  18. Two-color QCD with non-zero chiral chemical potential

    NASA Astrophysics Data System (ADS)

    Braguta, V. V.; Goy, V. A.; Ilgenfritz, E. M.; Kotov, A. Yu.; Molochkov, A. V.; Müller-Preussker, M.; Petersson, B.

    2015-06-01

    The phase diagram of two-color QCD with non-zero chiral chemical potential is studied by means of lattice simulation. We focus on the influence of a chiral chemical potential on the confinement/deconfinement phase transition and the breaking/restoration of chiral symmetry. The simulation is carried out with dynamical staggered fermions without rooting. The dependences of the Polyakov loop, the chiral condensate and the corresponding susceptibilities on the chiral chemical potential and the temperature are presented. The critical temperature is observed to increase with increasing chiral chemical potential.

  19. Fiber optic two-color vibration compensated interferometer for plasma density measurements

    SciTech Connect

    Van Zeeland, M. A.; Boivin, R. L.; Carlstrom, T. N.; Deterly, T.; Finkenthal, D. K.

    2006-10-15

    A fiber optic, heterodyne, two-color interferometer utilizing wavelength division multiplexing technology has been developed for measuring electron density in plasmas. Vibration compensation is accomplished via common path 1.31 and 1.55 {mu}m distributed feedback laser interferometers. All beam combining, splitting, frequency modulation, and collimation are accomplished by shared single-mode fiber optic components. Measurements of an argon radio-frequency generated plasma with electron densities of 10{sup 20} m{sup -3} show effective vibration compensation and typical line-density resolution of approximately 2x10{sup 19} m{sup -2}.

  20. Implication of transient receptor potential vanilloid type 1 in 14,15-epoxyeicosatrienoic acid-induced angiogenesis.

    PubMed

    Su, Kuo-Hui; Lee, Kuan-I; Shyue, Song-Kun; Chen, Hsiang-Ying; Wei, Jeng; Lee, Tzong-Shyuan

    2014-01-01

    14,15-epoxyeicosatrienoic acid (14,15-EET) is implicated in regulating physiological functions of endothelial cells (ECs), yet the potential molecular mechanisms underlying the beneficial effects in ECs are not fully understood. In this study, we investigated whether transient receptor potential vanilloid receptor type 1 (TRPV1) is involved in 14,15-EET-mediated Ca(2+) influx, nitric oxide (NO) production and angiogenesis. In human microvascular endothelial cells (HMECs), 14,15-EET time-dependently increased the intracellular level of Ca(2+). Removal of extracellular Ca(2+), pharmacological inhibition or genetic disruption of TRPV1 abrogated 14,15-EET-mediated increase of intracellular Ca(2+) level in HMECs or TRPV1-transfected HEK293 cells. Furthermore, removal of extracellular Ca(2+) or pharmacological inhibition of TRPV1 decreased 14,15-EET-induced NO production. 14,15-EET-mediated tube formation was abolished by TRPV1 pharmacological inhibition. In an animal experiment, 14,15-EET-induced angiogenesis was diminished by inhibition of TRPV1 and in TRPV1-deficient mice. TRPV1 may play a crucial role in 14,15-EET-induced Ca(2+) influx, NO production and angiogenesis. PMID:25210497

  1. Generation of strong terahertz field from two-color laser filamentation and optical rectification

    NASA Astrophysics Data System (ADS)

    Kuk, Donghoon; Yoo, Yungjun; Oh, Taek Il; You, Yong Sing; Kim, Ki-Yong

    2015-04-01

    We have demonstrated strong-field (>8 MV/cm), high-peak-power (12 MW) THz generation with a bandwidth of >20 THz via two-color laser filamentation. Moderate average power (1.4 mW) is also achieved by using a cryogenically-cooled Ti:sapphire amplifier capable of producing 30 fs, 15 mJ pulses at a 1 kHz repetition rate. For maximal THz generation and transmission, we have used a combination of a thin dichroic waveplate and a large Brewster-angled silicon filter. Here we have used a thin BBO crystal for frequency doubling (800 nm to 400 nm) and observed strong terahertz emission from the crystal itself. We also find that this type of terahertz emission can be optimized to yield more output power compared to two-color photoionization. In both cases, we have used a microbolometer camera for real-time THz beam profiling. This cost-effective THz camera along with our intense THz sources can be a useful tool for nonlinear THz studies including broadband THz spectroscopy and imaging. Work supported by DOE, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award No. 014216-001.

  2. An RNA-aptamer-based two-color CRISPR labeling system

    PubMed Central

    Wang, Siyuan; Su, Jun-Han; Zhang, Feng; Zhuang, Xiaowei

    2016-01-01

    The spatial organization and dynamics of chromatin play important roles in essential biological functions. However, direct visualization of endogenous genomic loci in living cells has proven to be laborious until the recent development of CRISPR-Cas9-based chromatin labeling methods. These methods rely on the recognition of specific DNA sequences by CRISPR single-guide RNAs (sgRNAs) and fluorescent–protein-fused catalytically inactive Cas9 to label specific chromatin loci in cells. Previously, multicolor chromatin labeling has been achieved using orthogonal Cas9 proteins from different bacterial species fused to different fluorescent proteins. Here we report the development of an alternative two-color CRISPR labeling method using only the well-characterized Streptococcus pyogenes Cas9, by incorporating MS2 or PP7 RNA aptamers into the sgRNA. The MS2 or PP7 aptamers then recruit the corresponding MS2 or PP7 coat proteins fused with different fluorescent proteins to the target genomic loci. Here we demonstrate specific and orthogonal two-color labeling of repetitive sequences in living human cells using this method. By attaching the MS2 or PP7 aptamers to different locations on the sgRNA, we found that extending the tetraloop and stem loop 2 of the sgRNA with MS2 or PP7 aptamers enhances the signal-to-background ratio of chromatin imaging. PMID:27229896

  3. Two-color QCD at imaginary chemical potential and its impact on real chemical potential

    NASA Astrophysics Data System (ADS)

    Kashiwa, Kouji; Sasaki, Takahiro; Kouno, Hiroaki; Yahiro, Masanobu

    2013-01-01

    We study properties of two-color QCD at imaginary chemical potential (μ) from the viewpoint of the Roberge-Weiss periodicity, the charge conjugation, and the pseudoreality. At μ=±iπT/2, where T is temperature, the system is symmetric under the combination of the charge conjugation C and the Z2 transformation. The symmetry, called CZ2 symmetry, is preserved at lower T but spontaneously broken at higher T. The Polyakov-loop extended Nambu-Jona-Lasinio model has the same properties as two-color QCD for CZ2 symmetry and the pseudoreality. The nontrivial correlation between the chiral restoration and the deconfinement are investigated by introducing the entanglement vertex in the Polyakov-loop extended Nambu-Jona-Lasinio model. The order of CZ2 symmetry breaking at the Roberge-Weiss end point is second order when the correlation is weak, but becomes first order when the correlation is strong. We also investigate the impact of the correlation on the phase diagram at real μ.

  4. Control of photoelectron interference in asymmetric momentum distributions using two-color laser fields

    NASA Astrophysics Data System (ADS)

    Zheng, Xu; Liu, Ming-Ming; Xie, Hui; Ge, Peipei; Li, Min; Liu, Yunquan

    2015-11-01

    We theoretically study the control of photoelectron interference of atoms ionized by a two-color laser field with parallel polarizations. Based on both the quantum-trajectory Monte Carlo model and an ab initio simulation with numerically solving the time-dependent Schrödinger equation, we show that the photoelectron angular distributions can be controlled by changing the relative phase of the two frequency components. The high-energy and low-energy photoelectrons show different modulations with respect to the relative phase. Tracing back to the initial coordinates (the ionization time with respect to the laser phase and the initial momentum) of photoelectrons, we have studied the physical origin of the asymmetric structure in photoelectron angular distributions and the dynamics of controlling photoelectron emission using the two-color laser fields. We show that the long tail of the Coulomb potential plays a minor role in the position of the high-energy cutoff in the backward scattering, whereas it is of great importance in the formation of the asymmetric structures of the low-energy photoelectrons.

  5. True temperature measurement on metallic surfaces using a two-color pyroreflectometer method.

    PubMed

    Hernandez, D; Netchaieff, A; Stein, A

    2009-09-01

    In the most common case of optical pyrometry, the major obstacle in determining the true temperature is the knowledge of the thermo-optical properties for in situ conditions. We present experimental results obtained with a method able to determine the true temperature of metallic surfaces above 500 degrees C when there is not parasitic effect by surrounding radiation. The method is called bicolor pyroreflectometry and it is based on Planck's law, Kirchhoff's law, and the assumption of identical reflectivity indicatrixes for the target surface at two different close wavelengths (here, 1.3 and 1.55 microm). The diffusion factor eta(d), the key parameter of the method, is introduced to determine the convergence temperature T(*), which is expected to be equal to the true temperature T. Our goal is to asses this method for different metallic surfaces. The validation of this method is made by comparison with thermocouples. Measurements were made for tungsten, copper, and aluminum samples of different roughnesses, determined by a rugosimeter. After introducing a theoretical model for two-color pyroreflectometry, we give a description of the experimental setup and present experimental applications of the subject method. The quality of the results demonstrates the usefulness of two-color pyroreflectometry to determine the temperatures of hot metals when the emissivity is not known and for the commercially important case of specular surfaces. PMID:19791957

  6. Two-color HgCdTe infrared staring focal plane arrays

    NASA Astrophysics Data System (ADS)

    Smith, Edward P.; Pham, Le T.; Venzor, Gregory M.; Norton, Elyse; Newton, Michael; Goetz, Paul; Randall, Valerie; Pierce, Gregory; Patten, Elizabeth A.; Coussa, Raymond A.; Kosai, Ken; Radford, William A.; Edwards, John; Johnson, Scott M.; Baur, Stefan T.; Roth, John A.; Nosho, Brett; Jensen, John E.; Longshore, Randolph E.

    2003-12-01

    Raytheon Vision Systems (RVS) in collaboration with HRL Laboratories is contributing to the maturation and manufacturing readiness of third-generation two-color HgCdTe infrared staring focal plane arrays (FPAs). This paper will highlight data from the routine growth and fabrication of 256x256 30μm unit-cell staring FPAs that provide dual-color detection in the mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) spectral regions. FPAs configured for MWIR/MWIR, MWIR/LWIR and LWIR/LWIR detection are used for target identification, signature recognition and clutter rejection in a wide variety of space and ground-based applications. Optimized triple-layer-heterojunction (TLHJ) device designs and molecular beam epitaxy (MBE) growth using in-situ controls has contributed to individual bands in all two-color FPA configurations exhibiting high operability (>99%) and both performance and FPA functionality comparable to state-of-the-art single-color technology. The measured spectral cross talk from out-of-band radiation for either band is also typically less than 10%. An FPA architecture based on a single mesa, single indium bump, and sequential mode operation leverages current single-color processes in production while also providing compatibility with existing second-generation technologies.

  7. Controlling electron-ion rescattering in two-color circularly polarized femtosecond laser fields

    NASA Astrophysics Data System (ADS)

    Mancuso, Christopher A.; Hickstein, Daniel D.; Dorney, Kevin M.; Ellis, Jennifer L.; Hasović, Elvedin; Knut, Ronny; Grychtol, Patrik; Gentry, Christian; Gopalakrishnan, Maithreyi; Zusin, Dmitriy; Dollar, Franklin J.; Tong, Xiao-Min; Milošević, Dejan B.; Becker, Wilhelm; Kapteyn, Henry C.; Murnane, Margaret M.

    2016-05-01

    High-harmonic generation driven by two-color counter-rotating circularly polarized laser fields was recently demonstrated experimentally as a breakthrough source of bright, coherent, circularly polarized beams in the extreme ultraviolet and soft-x-ray regions. However, the conditions for optimizing the single-atom yield are significantly more complex than for linearly polarized driving lasers and are not fully understood. Here we present a comprehensive study of strong-field ionization—the complementary process to high-harmonic generation—driven by two-color circularly polarized fields. We uncover the conditions that lead to enhanced electron-ion rescattering, which should correspond to the highest single-atom harmonic flux. Using a velocity map imaging photoelectron spectrometer and tomographic reconstruction techniques, we record three-dimensional photoelectron distributions resulting from the strong-field ionization of argon atoms across a broad range of driving laser intensity ratios. In combination with analytical predictions and advanced numerical simulations, we show that "hard" electron-ion rescattering is optimized when the second-harmonic field has an intensity approximately four times higher than that of the fundamental driving field. We also investigate electron-ion rescattering with co-rotating fields, and find that rescattering is significantly suppressed when compared with counter-rotating fields.

  8. An RNA-aptamer-based two-color CRISPR labeling system.

    PubMed

    Wang, Siyuan; Su, Jun-Han; Zhang, Feng; Zhuang, Xiaowei

    2016-01-01

    The spatial organization and dynamics of chromatin play important roles in essential biological functions. However, direct visualization of endogenous genomic loci in living cells has proven to be laborious until the recent development of CRISPR-Cas9-based chromatin labeling methods. These methods rely on the recognition of specific DNA sequences by CRISPR single-guide RNAs (sgRNAs) and fluorescent-protein-fused catalytically inactive Cas9 to label specific chromatin loci in cells. Previously, multicolor chromatin labeling has been achieved using orthogonal Cas9 proteins from different bacterial species fused to different fluorescent proteins. Here we report the development of an alternative two-color CRISPR labeling method using only the well-characterized Streptococcus pyogenes Cas9, by incorporating MS2 or PP7 RNA aptamers into the sgRNA. The MS2 or PP7 aptamers then recruit the corresponding MS2 or PP7 coat proteins fused with different fluorescent proteins to the target genomic loci. Here we demonstrate specific and orthogonal two-color labeling of repetitive sequences in living human cells using this method. By attaching the MS2 or PP7 aptamers to different locations on the sgRNA, we found that extending the tetraloop and stem loop 2 of the sgRNA with MS2 or PP7 aptamers enhances the signal-to-background ratio of chromatin imaging. PMID:27229896

  9. Experimental implementation of a strong two-color asymmetric laser field in the mid-infrared

    NASA Astrophysics Data System (ADS)

    Kaziannis, S.; Danakas, S.; Kotsina, N.; Kosmidis, C.

    2016-05-01

    We report the experimental implementation of a strong two-color (ω/2ω) asymmetric laser field in the mid-infrared regime (MIR) consisting of a fs pulse centered at 1400 nm and its second harmonic (700 nm). Control of the temporal delay between the two pulses with sub-cycle accuracy and, therefore, the two-color field phase is based on the use of a birefringent calcite plate. The experimental methodology is described in detail for the 1400/700 nm case, while its applicability is discussed for a broader wavelength range, nowadays accessible by optical parametric amplifiers. The validity of the proposed methodology is further supported by the application of the asymmetric 1400/700 nm field on the dissociative ionization of carbon monoxide, which is considered to be a benchmark target in the field of coherent control of strong laser‑matter interaction. It is demonstrated that efficient control on the directional emission of the CO ionic fragments is achieved by varying the relative phase of the 1400 and 700 nm field components.

  10. Two-color photons and nonlocality in fourth-order interference

    NASA Astrophysics Data System (ADS)

    Rarity, J. G.; Tapster, P. R.

    1990-05-01

    Angle-separated pair photons emitted in spontaneous parametric fluorescence are superimposed at a beamsplitter and detected by coincidence techniques. The coincidence disappears when the photon path lengths to the beamsplitter are equal to within their inverse bandwidth due to fourth-order interference. The photon bandwidth is set by wide apertures placed to satisfy phase-matching conditions at the nonlinear crystal. The resulting broadband photons are short (39-fs full width at half maximum) and show an oscillatory tail resulting from the hard-edge apertures. Two-color photons are created by blocking the central portion of the apertures leading to strong oscillations of the coincidence rate as a function of path-length difference. Both effects are predicted by the theory of fourth-order interference coupled with the detailed phase-matching conditions in the nonlinear crystal used as a source. The two colors overlap at different positions on the beamsplitter. We show how this could be used as a test of local realistic theories by formulating a Bell inequality based on relative phases between the colors.

  11. Micron Scale Mineralogy

    NASA Astrophysics Data System (ADS)

    Caldwell, W. A.; Tamura, N.; Celestre, R. S.; Padmore, H. A.; Patel, J. R.

    2002-12-01

    Although x-ray diffraction has been used for nearly a century as the mineralogist's definitive tool in determining crystalline structures, it has proved impossible to use this technique to spatially resolve the highly heterogeneous nature of many minerals at the mesoscopic level. Due to recent revolutions in the brightness of x-ray sources and in our ability to focus x-rays, we can now carry out conventional monochromatic rotation crystallography as well as Laue diffraction with sub-micron spatial resolution and produce maps of orientation, strain, mineral type, and even chemical speciation over tens of microns in a short amount of time. We have pioneered the development of these techniques at the 3rd generation synchrotron radiation source (Advanced Light Source) in Berkeley, and will describe their application to understanding the structure of a quartz-geode. Our results show the manner in which grain structure and texture change as a function of distance from the cavity wall and are compared with models of crystal growth in such systems. This example highlights the great utility of a synchrotron based x-ray micro-diffraction beamline and the possibilities it opens to the mineralogist.

  12. Airborne Astronomy with a 150 microns - 400 microns Heterodyne Spectrometer

    NASA Technical Reports Server (NTRS)

    Betz, A. L.

    1995-01-01

    This report summarizes work done under NASA Grant NAG2-753 awarded to the University of Colorado. The project goal was to build a far-infrared heterodyne spectrometer for NASA's Kuiper Airborne Observatory, and to use this instrument to observe atomic and molecular spectral lines from the interstellar medium. This goal was successfully achieved. Detections of particular note have been the 370 micron line of neutral atomic carbon, the 158 micron transition of ionized carbon, many of the high-J rotational lines of CO-12 and CO-13 between J=9-8 and J=22-21, the 119 micron and 163 micron rotational lines of OH, the 219 micron ground-state rotational line of H2D(+), and the 63 micron fine structure line of neutral atomic oxygen. All of these lines were observed at spectral resolutions exceeding 1 part in 10(exp 6) thereby allowing accurate line shapes and Doppler velocities to be measured.

  13. Sub-micron filter

    DOEpatents

    Tepper, Frederick; Kaledin, Leonid

    2009-10-13

    Aluminum hydroxide fibers approximately 2 nanometers in diameter and with surface areas ranging from 200 to 650 m.sup.2/g have been found to be highly electropositive. When dispersed in water they are able to attach to and retain electronegative particles. When combined into a composite filter with other fibers or particles they can filter bacteria and nano size particulates such as viruses and colloidal particles at high flux through the filter. Such filters can be used for purification and sterilization of water, biological, medical and pharmaceutical fluids, and as a collector/concentrator for detection and assay of microbes and viruses. The alumina fibers are also capable of filtering sub-micron inorganic and metallic particles to produce ultra pure water. The fibers are suitable as a substrate for growth of cells. Macromolecules such as proteins may be separated from each other based on their electronegative charges.

  14. Fabrication of optical multilayer for two-color phase plate in super-resolution microscope

    NASA Astrophysics Data System (ADS)

    Iketaki, Yoshinori; Kitagawa, Katsuichi; Hidaka, Kohjiro; Kato, Naoki; Hirabayashi, Akira; Bokor, Nandor

    2014-07-01

    In super-resolution microscopy based on fluorescence depletion, the two-color phase plate (TPP) is an indispensable optical element, which can independently control the phase shifts for two beams of different color, i.e., the pump and erase beams. By controlling a phase shift of the erase beam through the TPP, the erase beam can be modulated into a doughnut shape, while the pump beam maintains the initial Gaussian shape. To obtain a reliable optical multiplayer (ML) for the TPP, we designed a ML with only two optical layers by performing numerical optimization. The measured phase shifts generated by the fabricated ML using interferometry correspond to the design values. The beam profiles in the focal plane are also consistent with theoretical results. Although the fabricated ML consists of only two optical layers, the ML can provide a suitable phase modulation function for the TPP in a practical super-resolution microscope.

  15. Two-color photoexcitation of Rydberg states via an electric quadrupole transition

    SciTech Connect

    Li Leping; Gu Quanli; Knee, J. L.; Wright, J. D.; DiSciacca, J. M.; Morgan, T. J.

    2008-03-15

    We report the observation of an electric quadrupole transition between the 4s{sup '}[1/2]{sub 0}{sup o} and 3d[3/2]{sub 2}{sup o} states in the spectrum of argon and use it in the first step of a scheme to excite Rydberg states. The initial identification of the transition is based on one-color, two-photon photoionization. A different experiment utilizing two-color, two-photon photoexcitation to Rydberg states confirms the identification. Despite the unavoidable background of one-color, two-photon photoionization, the latter experimental technique makes possible two-photon spectroscopy of Rydberg states using a resonant intermediate state populated by an electric quadrupole transition.

  16. Generation of scalable terahertz radiation from cylindrically focused two-color laser pulses in air

    NASA Astrophysics Data System (ADS)

    Kuk, D.; Yoo, Y. J.; Rosenthal, E. W.; Jhajj, N.; Milchberg, H. M.; Kim, K. Y.

    2016-03-01

    We demonstrate scalable terahertz (THz) generation by focusing terawatt, two-color laser pulses in air with a cylindrical lens. This focusing geometry creates a two-dimensional air plasma sheet, which yields two diverging THz lobe profiles in the far field. This setup can avoid plasma-induced laser defocusing and subsequent THz saturation, previously observed with spherical lens focusing of high-power laser pulses. By expanding the plasma source into a two-dimensional sheet, cylindrical focusing can lead to scalable THz generation. This scheme provides an energy conversion efficiency of 7 × 10-4, ˜7 times better than spherical lens focusing. The diverging THz lobes are refocused with a combination of cylindrical and parabolic mirrors to produce strong THz fields (>21 MV/cm) at the focal point.

  17. Two color satellite laser ranging upgrades at Goddard's 1.2m telescope facility

    NASA Technical Reports Server (NTRS)

    Zagwodzki, Thomas W.; Mcgarry, Jan F.; Degnan, John J.; Varghese, Thomas K.

    1993-01-01

    The ranging laboratory at Goddard's 1.2 m telescope tracking facility has recently been upgraded to include a single photoelectron sensitive Hamamatsu streak camera-based range receiver which uses doubled and tripled Nd:YAG frequencies for satellite laser ranging. Other ranging system upgrades include a new continuum laser, which will deliver up to 30 millijoules (mJ) at both 532 and 355 nm at a pulsewidth of 30 picoseconds (FWHM), and replacement of both ranging and tracking computers with COMPAQ 386 based systems. Preliminary results using a photomultiplier-tube based receiver and waveform digitizer indicate agreement within the accuracy of the measurement with the theoretical Marini and Murray model for atmospheric refraction. Two color streak camera measurements are used to further analyze the accuracy of these and other atmospheric refraction models.

  18. Direct and Indirect Two-color Coherent Control in Bulk Silicon

    NASA Astrophysics Data System (ADS)

    Cheng, Jinluo; Rioux, Julien; Sipe, John

    2012-02-01

    Using an empirical pseudopotential model for electron states and an adiabatic bond charge model for phonon states, we investigate the two-color direct and indirect coherent current injection with an incident optical field composed of a fundamental frequency and its second harmonic, and calculate the response tensors of the electron (hole) charge and spin currents. We show the current control for three different polarization scenarios: For co-circularly polarized beams, the direction of the charge current and the polarization direction of the spin current can be controlled by a relative-phase parameter; for the co-linearly and cross-linearly polarized beams, the current amplitude can be controlled by that parameter. For the indirect gap injection, the spectral dependence of the maximum swarm velocity shows that the direction of charge current reverses under an increase in photon energy.

  19. Decrease in deformation rate observed by two-color laser ranging in Long Valley Caldera

    USGS Publications Warehouse

    Linker, M.F.; Langbein, J.O.; McGarr, A.

    1986-01-01

    After the January 1983 earthquake swarm, the last period of notable seismicity, the rapid rate of deformation of the south moat and resurgent dome of the Long Valley caldera diminished. Frequently repeated two-color laser ranging measurements made within a geodetic network in the caldera during the interval June 1983 to November 1984 reveal that, although the deformation accumulated smoothly in time, the rate of extension of many of the baselines decreased by factors of 2 to 3 from mid-1983 to mid-1984. Areal dilatation was the dominant signal during this period, with rates of extension of several baselines reaching as high as 5 parts per million per annum during the summer of 1983. Within the south moat, shear deformation also was apparent. The cumulative deformation can be modeled as the result of injection of material into two points located beneath the resurgent dome in addition to shallow right lateral slip on a vertical fault in the south moat.

  20. Design of a real-time two-color interferometer for MAST Upgrade

    SciTech Connect

    O’Gorman, T. Naylor, G.; Scannell, R.; Cunningham, G.; Martin, R.; Croft, D.; Brunner, K. J.

    2014-11-15

    A single chord two-color CO{sub 2}/HeNe (10.6/0.633 μm) heterodyne laser interferometer has been designed to measure the line integral electron density along the mid-plane of the MAST Upgrade tokamak, with a typical error of 1 × 10{sup 18} m{sup −3} (∼2° phase error) at 4 MHz temporal resolution. To ensure this diagnostic system can be restored from any failures without stopping MAST Upgrade operations, it has been located outside of the machine area. The final design and initial testing of this system, including details of the optics, vibration isolation, and a novel phase detection scheme are discussed in this paper.

  1. Quantitative surface temperature measurement using two-color thermographic phosphors and video equipment

    NASA Technical Reports Server (NTRS)

    Buck, Gregory M. (Inventor)

    1989-01-01

    A thermal imaging system provides quantitative temperature information and is particularly useful in hypersonic wind tunnel applications. An object to be measured is prepared by coating with a two-color, ultraviolet-activated, thermographic phosphor. The colors emitted by the phosphor are detected by a conventional color video camera. A phosphor emitting blue and green light with a ratio that varies depending on temperature is used so that the intensity of light in the blue and green wavelengths detected by the blue and green tubes in the video camera can be compared. Signals representing the intensity of blue and green light at points on the surface of a model in a hypersonic wind tunnel are used to calculate a ratio of blue to green light intensity which provides quantitative temperature information for the surface of the model.

  2. Hadron wave functions as a probe of a two-color baryonic medium

    NASA Astrophysics Data System (ADS)

    Amato, Alessandro; Giudice, Pietro; Hands, Simon

    2015-04-01

    The properties of the ground state of two-color QCD at non-zero baryon chemical potential μ present an interesting problem in strongly interacting gauge theory; in particular the nature of the physically relevant degrees of freedom in the superfluid phase in the post-onset regime μ > m π /2 still needs clarification. In this study we present evidence for in-medium effects at high μ by studying the wave functions of mesonic and diquark states using orthodox lattice simulation techniques, made possible by the absence of a sign problem for the model with N f = 2. Our results show that beyond onset the spatial extent of hadrons decreases as μ grows, and that the wave function profiles are consistent with the existence of a dynamically gapped Fermi surface in this regime.

  3. Theoretical and experimental analyses of the performance of two-color laser ranging systems

    NASA Technical Reports Server (NTRS)

    Im, K. E.; Gardner, C. S.

    1985-01-01

    The statistical properties of the signals reflected from the retroreflector equipped satellites were studied. It is found that coherence interference between pulse reflections from retroreflectors of different ranges on the array platform is the primary cause of signal fluctuations. The performance of a cross-correlation technique to estimate the differential propagation time is analyzed by considering both shot noise and speckle. For the retroreflector arrays, timing performance is dominated by interference induced speckle, and the differential propagation time cannot be resolved to better than the pulse widths of the received signals. The differential timing measurements obtained over a horizontal path are analyzed. The ocean-reflected pulse measurements obtained from the airborne two-color laser altimeter experiment are presented.

  4. Two color satellite laser ranging upgrades at Goddard's 1.2m telescope facility

    NASA Astrophysics Data System (ADS)

    Zagwodzki, Thomas W.; McGarry, Jan F.; Degnan, John J.; Varghese, Thomas K.

    1993-06-01

    The ranging laboratory at Goddard's 1.2 m telescope tracking facility has recently been upgraded to include a single photoelectron sensitive Hamamatsu streak camera-based range receiver which uses doubled and tripled Nd:YAG frequencies for satellite laser ranging. Other ranging system upgrades include a new continuum laser, which will deliver up to 30 millijoules (mJ) at both 532 and 355 nm at a pulsewidth of 30 picoseconds (FWHM), and replacement of both ranging and tracking computers with COMPAQ 386 based systems. Preliminary results using a photomultiplier-tube based receiver and waveform digitizer indicate agreement within the accuracy of the measurement with the theoretical Marini and Murray model for atmospheric refraction. Two color streak camera measurements are used to further analyze the accuracy of these and other atmospheric refraction models.

  5. Coherent control of broadband isolated attosecond pulses in a chirped two-color laser field

    SciTech Connect

    Zou Pu; Zeng Zhinan; Zheng Yinghui; Lu Yingying; Liu Peng; Li Ruxin; Xu Zhizhan

    2010-03-15

    A theoretical investigation is presented that uses a strong two-color laser field composed of a linearly chirped fundamental (900 nm) and its subharmonic (1800-nm) laser pulses to control coherently the broadband isolated attosecond pulses in high-order harmonic generations. After the subharmonic field is added, the intrinsic chirp of harmonic emission can be reduced significantly, and consequently, the temporal synchronization of harmonic emission with different photon energies at the level of the single-atom response can be realized. In addition, the scheme is robust against the carrier envelope phase variation to produce a twin pulse of stable sub-100-as duration, and the relative intensity of the twin pulses can be changed just by adjusting the relative time delay of the two driving pulses, which is of benefit in general pump-probe experiments.

  6. Infrared Two-Color Multicycle Laser Field Synthesis for Generating an Intense Attosecond Pulse

    NASA Astrophysics Data System (ADS)

    Takahashi, Eiji J.; Lan, Pengfei; Mücke, Oliver D.; Nabekawa, Yasuo; Midorikawa, Katsumi

    2010-06-01

    We propose and demonstrate the generation of a continuum high-order harmonic spectrum by mixing multicycle two-color (TC) laser fields with the aim of obtaining an intense isolated attosecond pulse. By optimizing the wavelength of a supplementary infrared pulse in a TC field, a continuum harmonic spectrum was created around the cutoff region without carrier-envelope phase stabilization. The obtained harmonic spectra clearly show the possibility of generating isolated attosecond pulses from a multicycle TC laser field, which is generated by an 800 nm, 30 fs pulse mixed with a 1300 nm, 40 fs pulse. Our proposed method enables us not only to relax the requirements for the pump pulse duration but also to reduce ionization of the harmonic medium. This concept opens the door to create an intense isolated attosecond pulse using a conventional femtosecond laser system.

  7. Two-Color Strong-Field Photoelectron Spectroscopy and the Phase of the Phase.

    PubMed

    Skruszewicz, S; Tiggesbäumker, J; Meiwes-Broer, K-H; Arbeiter, M; Fennel, Th; Bauer, D

    2015-07-24

    The presence of a weak second-harmonic field in an intense-laser ionization experiment affects the momentum-resolved electron yield, depending on the relative phase between the ω and the 2ω component. The proposed two-color "phase-of-the-phase spectroscopy" quantifies for each final electron momentum a relative-phase contrast (RPC) and a phase of the phase (PP) describing how much and with which phase lag, respectively, the yield changes as a function of the relative phase. Experimental results for RPC and PP spectra for rare gas atoms and CO_{2} are presented. The spectra demonstrate a rather universal structure that is analyzed with the help of a simple model based on electron trajectories, wave-packet spreading, and (multiple) rescattering. Details in the PP and RPC spectra are target sensitive and, thus, may be used to extract structural (or even dynamical) information with high accuracy. PMID:26252678

  8. Design of a real-time two-color interferometer for MAST Upgrade.

    PubMed

    O'Gorman, T; Naylor, G; Scannell, R; Cunningham, G; Brunner, K J; Martin, R; Croft, D

    2014-11-01

    A single chord two-color CO2/HeNe (10.6/0.633 μm) heterodyne laser interferometer has been designed to measure the line integral electron density along the mid-plane of the MAST Upgrade tokamak, with a typical error of 1 × 10(18) m(-3) (∼2° phase error) at 4 MHz temporal resolution. To ensure this diagnostic system can be restored from any failures without stopping MAST Upgrade operations, it has been located outside of the machine area. The final design and initial testing of this system, including details of the optics, vibration isolation, and a novel phase detection scheme are discussed in this paper. PMID:25430274

  9. Fabrication of optical multilayer for two-color phase plate in super-resolution microscope

    SciTech Connect

    Iketaki, Yoshinori; Kitagawa, Katsuichi; Hidaka, Kohjiro; Kato, Naoki; Hirabayashi, Akira; Bokor, Nandor

    2014-07-15

    In super-resolution microscopy based on fluorescence depletion, the two-color phase plate (TPP) is an indispensable optical element, which can independently control the phase shifts for two beams of different color, i.e., the pump and erase beams. By controlling a phase shift of the erase beam through the TPP, the erase beam can be modulated into a doughnut shape, while the pump beam maintains the initial Gaussian shape. To obtain a reliable optical multiplayer (ML) for the TPP, we designed a ML with only two optical layers by performing numerical optimization. The measured phase shifts generated by the fabricated ML using interferometry correspond to the design values. The beam profiles in the focal plane are also consistent with theoretical results. Although the fabricated ML consists of only two optical layers, the ML can provide a suitable phase modulation function for the TPP in a practical super-resolution microscope.

  10. Memory effects, two color percolation, and the temperature dependence of Mott variable-range hopping

    NASA Astrophysics Data System (ADS)

    Agam, Oded; Aleiner, Igor L.

    2014-06-01

    There are three basic processes that determine hopping transport: (a) hopping between normally empty sites (i.e., having exponentially small occupation numbers at equilibrium), (b) hopping between normally occupied sites, and (c) transitions between normally occupied and unoccupied sites. In conventional theories all these processes are considered Markovian and the correlations of occupation numbers of different sites are believed to be small (i.e., not exponential in temperature). We show that, contrary to this belief, memory effects suppress the processes of type (c) and manifest themselves in a subleading exponential temperature dependence of the variable-range hopping conductivity. This temperature dependence originates from the property that sites of type (a) and (b) form two independent resistor networks that are weakly coupled to each other by processes of type (c). This leads to a two-color percolation problem which we solve in the critical region.

  11. Mechanisms of two-color laser-induced field-free molecular orientation.

    PubMed

    Spanner, Michael; Patchkovskii, Serguei; Frumker, Eugene; Corkum, Paul

    2012-09-14

    Two mechanisms of two-color (ω+2ω) laser-induced field-free molecular orientation, based on the hyperpolarizability and ionization depletion, are explored and compared. The CO molecule is used as a computational example. While the hyperpolarizability mechanism generates small amounts of orientation at intensities below the ionization threshold, ionization depletion quickly becomes the dominant mechanism as soon as ionizing intensities are reached. Only the ionization mechanism leads to substantial orientation (e.g., on the order of ≳0.1). For intensities typical of laser-induced molecular alignment and orientation experiments, the two mechanisms lead to robust, characteristic timings of the field-free orientation wave-packet revivals relative to the alignment revivals and the revival time. The revival timings can be used to detect the active orientation mechanism experimentally. PMID:23005623

  12. Attosecond x-ray source generation from two-color polarized gating plasmonic field enhancement

    SciTech Connect

    Feng, Liqiang; State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 ; Yuan, Minghu; Chu, Tianshu; Institute for Computational Sciences and Engineering, Laboratory of New Fiber Materials and Modern Textile, The Growing Base for State Key Laboratory, Qingdao University, Qingdao 266071

    2013-12-15

    The plasmonic field enhancement from the vicinity of metallic nanostructures as well as the polarization gating technique has been utilized to the generation of the high order harmonic and the single attosecond x-ray source. Through numerical solution of the time-dependent Schrödinger equation, for moderate the inhomogeneity and the polarized angle of the two fields, we find that not only the harmonic plateau has been extended and enhanced but also the single short quantum path has been selected to contribute to the harmonic. As a result, a series of 50 as pulses around the extreme ultraviolet and the x-ray regions have been obtained. Furthermore, by investigating the other parameters effects on the harmonic emission, we find that this two-color polarized gating plasmonic field enhancement scheme can also be achieved by the multi-cycle pulses, which is much better for experimental realization.

  13. Synthesis of Two-Color Laser Pulses for the Harmonic Cutoff Extension

    NASA Astrophysics Data System (ADS)

    Wang, Guo-Li; Zhou, Li-Hua; Zhao, Song-Feng; Zhou, Xiao-Xin

    2016-05-01

    Increasing simultaneously both the cutoff energy and efficiency is a big challenge to all applications of high-order harmonic generation (HHG). For this purpose, the shaping of the waveform of driving pulse is an alternative approach. Here, we show that the harmonic cutoff can be extended by about two times without reducing harmonic yield after considering macroscopic propagation effects, by adopting a practical way to synthesize two-color fields with fixed energy. Our results, combined with the experimental techniques, show the great potential of HHG as a tabletop light source. Supported by the National Natural Science Foundation of China under Grant Nos. 11264036, 11164025, 11364038, the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No. 20116203120001, and the Basic Scientific Research Foundation for Institution of Higher Learning of Gansu Province

  14. BEC-BCS crossover in a cold and magnetized two color NJL model

    NASA Astrophysics Data System (ADS)

    Duarte, Dyana C.; Allen, P. G.; Farias, R. L. S.; Manso, Pedro H. A.; Ramos, Rudnei O.; Scoccola, N. N.

    2016-01-01

    The BEC-BCS crossover for a Nambu-Jona-Lasinio (NJL) model with diquark interactions is studied in the presence of an external magnetic field. Particular attention is paid to different regularization schemes used in the literature. A thorough comparison of results is performed for the case of a cold and magnetized two-color NJL model. According to our results, the critical chemical potential for the BEC transition exhibits a clear inverse magnetic catalysis effect for magnetic fields in the range 1 ≲e B /mπ2≲20 . As for the BEC-BCS crossover, the corresponding critical chemical potential is very weakly sensitive to magnetic fields up to e B ˜9 mπ2, showing a much smaller inverse magnetic catalysis as compared to the BEC transition, and displays a strong magnetic catalysis from this point on.

  15. Physics of the conical broadband terahertz emission from two-color laser-induced plasma filaments

    NASA Astrophysics Data System (ADS)

    Gorodetsky, Andrei; Koulouklidis, Anastasios D.; Massaouti, Maria; Tzortzakis, Stelios

    2014-03-01

    We propose a comprehensive physical model explaining the conical character of broadband terahertz generation from femtosecond two-color laser-induced air plasma filaments. We show, that, in contrast to other models, emission is always conical, resulting from phase matching of the radiation produced inside the filament combined with a partial back reflection of the generated terahertz field from the filament itself due to the frequency-dependent critical plasma density. The obtained conical angle varies from 2∘ to 10∘, depending on the plasma density distribution and filament length. Unlike previously proposed models, our model shows good agreement with our experiments as well as a wide range of experimental findings from the literature.

  16. Angle resolved photoelectron spectroscopy of two-color XUV–NIR ionization with polarization control

    NASA Astrophysics Data System (ADS)

    Düsterer, S.; Hartmann, G.; Babies, F.; Beckmann, A.; Brenner, G.; Buck, J.; Costello, J.; Dammann, L.; De Fanis, A.; Geßler, P.; Glaser, L.; Ilchen, M.; Johnsson, P.; Kazansky, A. K.; Kelly, T. J.; Mazza, T.; Meyer, M.; Nosik, V. L.; Sazhina, I. P.; Scholz, F.; Seltmann, J.; Sotoudi, H.; Viefhaus, J.; Kabachnik, N. M.

    2016-08-01

    Electron emission caused by extreme ultraviolet (XUV) radiation in the presence of a strong near infrared (NIR) field leads to multiphoton interactions that depend on several parameters. Here, a comprehensive study of the influence of the angle between the polarization directions of the NIR and XUV fields on the two-color angle-resolved photoelectron spectra of He and Ne is presented. The resulting photoelectron angular distribution strongly depends on the orientation of the NIR polarization plane with respect to that of the XUV field. The prevailing influence of the intense NIR field over the angular emission characteristics for He(1s) and Ne(2p) ionization lines is shown. The underlying processes are modeled in the frame of the strong field approximation (SFA) which shows very consistent agreement with the experiment reaffirming the power of the SFA for multicolor-multiphoton ionization in this regime.

  17. Two-Color Strong-Field Photoelectron Spectroscopy and the Phase of the Phase

    NASA Astrophysics Data System (ADS)

    Skruszewicz, S.; Tiggesbäumker, J.; Meiwes-Broer, K.-H.; Arbeiter, M.; Fennel, Th.; Bauer, D.

    2015-07-01

    The presence of a weak second-harmonic field in an intense-laser ionization experiment affects the momentum-resolved electron yield, depending on the relative phase between the ω and the 2 ω component. The proposed two-color "phase-of-the-phase spectroscopy" quantifies for each final electron momentum a relative-phase contrast (RPC) and a phase of the phase (PP) describing how much and with which phase lag, respectively, the yield changes as a function of the relative phase. Experimental results for RPC and PP spectra for rare gas atoms and CO2 are presented. The spectra demonstrate a rather universal structure that is analyzed with the help of a simple model based on electron trajectories, wave-packet spreading, and (multiple) rescattering. Details in the PP and RPC spectra are target sensitive and, thus, may be used to extract structural (or even dynamical) information with high accuracy.

  18. Spectral Linewidth Narrowing and Tunable Two-Color Laser Operation of Two Diode Laser Arrays

    SciTech Connect

    Liu, Bo; Braiman, Yehuda

    2012-01-01

    We propose and implement a common external cavity to narrow spectral linewidth of two broad-area laser diode arrays (LDAs) and align their center wavelengths. The locked center wavelength of two LDAs can be tuned in the range of {approx}10 nm by tuning the tilted angle of the diffraction grating. The output beams of two LDAs are spatially overlapped through the polarization beam splitter of the common external cavity, and the total output power equals the power of two LDAs. The center wavelength of each LDA can be independently tuned by shifting the corresponding fast-axis collimation lens. As a result, the high-power two-color LDA operation is demonstrated with the tunable wavelength difference of up to 2 nm ({approx}1 THz).

  19. In Silico Comparative Transcriptome Analysis of Two Color Morphs of the Common Coral Trout (Plectropomus Leopardus)

    PubMed Central

    Wang, Le; Yu, Cuiping; Guo, Liang; Lin, Haoran; Meng, Zining

    2015-01-01

    The common coral trout is one species of major importance in commercial fisheries and aquaculture. Recently, two different color morphs of Plectropomus leopardus were discovered and the biological importance of the color difference is unknown. Since coral trout species are poorly characterized at the molecular level, we undertook the transcriptomic characterization of the two color morphs, one black and one red coral trout, using Illumina next generation sequencing technologies. The study produced 55162966 and 54588952 paired-end reads, for black and red trout, respectively. De novo transcriptome assembly generated 95367 and 99424 unique sequences in black and red trout, respectively, with 88813 sequences shared between them. Approximately 50% of both trancriptomes were functionally annotated by BLAST searches against protein databases. The two trancriptomes were enriched into 25 functional categories and showed similar profiles of Gene Ontology category compositions. 34110 unigenes were grouped into 259 KEGG pathways. Moreover, we identified 14649 simple sequence repeats (SSRs) and designed primers for potential application. We also discovered 130524 putative single nucleotide polymorphisms (SNPs) in the two transcriptomes, supplying potential genomic resources for the coral trout species. In addition, we identified 936 fast-evolving genes and 165 candidate genes under positive selection between the two color morphs. Finally, 38 candidate genes underlying the mechanism of color and pigmentation were also isolated. This study presents the first transcriptome resources for the common coral trout and provides basic information for the development of genomic tools for the identification, conservation, and understanding of the speciation and local adaptation of coral reef fish species. PMID:26713756

  20. Palmitoylethanolamide: problems regarding micronization, ultra-micronization and additives.

    PubMed

    Kriek, Rutger

    2014-06-01

    It can be established that at least two of the writers of the article published in 'Inflammopharmacology', title: 'Palmitoylethanolamide (PEA), a naturally occurring disease-modifying agent in neuropathic pain' have a direct connection to the companies Epitech and Innovet. These companies produce micronized and ultra-micronized PEA. Therefore it is of eminent importance to determine whether the statements in this paper have also taken into consideration the European guidelines for Good Clinical Practice and the codes of good scientific practices. This is very questionable. A minimum condition in clinical studies for proving the claim that PEA in its micronized and ultra-micronized formulations works better than in its pure form or in other formulations is that a comparison be made between: PEA in pure form or in other formulations, on the one hand; PEA in the micronized and ultra-micronized formulations, on the other hand. This minimum condition is not complied with. Based on additional studies discussed in this commentary and in view of the effects of ultra-micronization on the parameters discussed, as well as the potential side-effects of additives such as excipients and herbal extracts added to the products cited in the article, the preference should be for the time being to treat patients with pure PEA without any of these additives. PMID:24647619

  1. Two-photon indirect optical injection and two-color coherent control in bulk silicon

    NASA Astrophysics Data System (ADS)

    Cheng, J. L.; Rioux, J.; Sipe, J. E.

    2011-12-01

    Using an empirical pseudopotential description of electron states and an adiabatic bond charge model for phonon states in bulk silicon, we theoretically investigate two-photon indirect optical injection of carriers and spins and two-color coherent control of the motion of the injected carriers and spins. For two-photon indirect carrier and spin injection, we identify the selection rules of band edge transitions, the injection in each conduction band valley, and the injection from each phonon branch at 4 and 300 K. At 4 K, the TA-phonon-assisted transitions dominate the injection at low photon energies and the TO-phonon-assisted transitions at high photon energies. At 300 K, the former dominates at all photon energies of interest. The carrier injection shows anisotropy and linear-circular dichroism with respect to the light propagation direction. For light propagating along the <001> direction, the carrier injection exhibits valley anisotropy, and the injection into the Z conduction band valley is larger than that into the X and Y valleys. For σ- light propagating along the <001> (<111>) direction, the degree of spin polarization gives a maximum value about 20% (6%) at 4 K and -10% (20%) at 300 K, and at both temperature shows abundant structure near the injection edges due to contributions from different phonon branches. For two-color coherent current injection with an incident optical field composed of a fundamental frequency and its second harmonic, the response tensors of the electron (hole) charge and spin currents are calculated at 4 and 300 K. We show the current control for three different polarization scenarios: For cocircularly polarized beams, the direction of the charge current and the polarization direction of the spin current can be controlled by a relative-phase parameter; for the collinearly and cross-linearly polarized beams, the current amplitude can be controlled by that parameter. The spectral dependence of the maximum swarm velocity shows that

  2. Control of threshold enhancements in harmonic generation by atoms in a two-color laser field with orthogonal polarizations

    NASA Astrophysics Data System (ADS)

    Frolov, M. V.; Manakov, N. L.; Sarantseva, T. S.; Silaev, A. A.; Vvedenskii, N. V.; Starace, Anthony F.

    2016-02-01

    Threshold phenomena (or channel-closing effects) are analyzed in high-order harmonic generation (HHG) by atoms in a two-color laser field with orthogonal linearly polarized components of a fundamental field and its second harmonic. We show that the threshold behavior of HHG rates for the case of a weak second harmonic component is sensitive to the parity of a closing multiphoton ionization channel and the spatial symmetry of the initial bound state of the target atom, while for the case of comparable intensities of both components, suppression of threshold phenomena is observed as the relative phase between the components of a two-color field varies. A quantum orbit analysis as well as phenomenological considerations in terms of Baz' theory of threshold phenomena [Zh. Eksp. Teor. Fiz. 33, 923 (1957)] are presented in order to describe and explain the major features of threshold phenomena in HHG by a two-color field.

  3. Two-color method for optical astrometry - Theory and preliminary measurements with the Mark III stellar interferometer

    NASA Technical Reports Server (NTRS)

    Colavita, M. Mark; Shao, Michael; Staelin, David H.

    1987-01-01

    The two-color method for interferometric astrometry provides a means of reducing the error in a stellar position measurement attributable to atmospheric turbulence. The primary limitation of the method is shown to be turbulent water vapor fluctuations. Secondary atmospheric effects caused by diffraction from small refractive-index inhomogeneities and differential refraction for the observation of stars away from zenith are shown to introduce errors that behave as white noise and which should not be significant. Other potential error sources due to photon noise, systematic instrumental effects, and imperfect data reduction are also considered. The improvement in accuracy possible with the two-color method is estimated as a factor of 5-10 over the corresponding one-color measurement. Some preliminary two-color measurements with the Mark III stellar interferometer at Mt. Wilson are presented, which demonstrate a factor of about 5 reduction in the amplitude of the atmospheric fluctuations in a stellar position measurement.

  4. Frequency modulation of high-order harmonic generation in an orthogonally polarized two-color laser field.

    PubMed

    Li, Guicun; Zheng, Yinghui; Ge, Xiaochun; Zeng, Zhinan; Li, Ruxin

    2016-08-01

    We have experimentally investigated the frequency modulation of high-order harmonics in an orthogonally polarized two-color laser field consisting of a mid-infrared 1800nm fundamental pulse and its second harmonic pulse. It is demonstrated that the high harmonic spectra can be fine-tuned as we slightly change the relative delay of the two-color laser pulses. By analyzing the relative frequency shift of each harmonic at different two-color delays, the nonadiabatic spectral shift induced by the rapid variation of the intensity-dependent intrinsic dipole phase can be distinguished from the blueshift induced by the change of the refractive index during self-phase modulation (SPM). Our comprehensive analysis shows that the frequency modulation pattern is a reflection of the average emission time of high-order harmonic generation (HHG), thus offering a simple method to fine-tune the spectra of the harmonics on a sub-cycle time scale. PMID:27505831

  5. Large-bandwidth two-color free-electron laser driven by a comb-like electron beam

    NASA Astrophysics Data System (ADS)

    Ronsivalle, C.; Anania, M. P.; Bacci, A.; Bellaveglia, M.; Chiadroni, E.; Cianchi, A.; Ciocci, F.; Dattoli, G.; Di Giovenale, D.; Di Pirro, G.; Ferrario, M.; Gatti, G.; Giannessi, L.; Mostacci, A.; Musumeci, P.; Palumbo, L.; Petralia, A.; Petrillo, V.; Pompili, R.; Rau, J. V.; Rossi, A. R.; Vaccarezza, C.; Villa, F.

    2014-03-01

    We discuss a two-color SASE free-electron laser (FEL) amplifier where the time and energy separation of two separated radiation pulses are controlled by manipulation of the electron beam phase space. Two electron beamlets with adjustable time and energy spacing are generated in an RF photo-injector illuminating the cathode with a comb-like laser pulse followed by RF compression in the linear accelerator. We review the electron beam manipulation technique to generate bunches with time and energy properties suitable for driving two-color FEL radiation. Experimental measurements at the SPARC-LAB facility illustrate the flexibility of the scheme for the generation of two-color FEL spectra.

  6. Two-color excitation system for fluorescence detection in DNA sequencing by capillary array electrophoresis.

    PubMed

    Xue, Gang; Yeung, Edward S

    2002-05-01

    Two computer-controlled galvanometer scanners are adapted for two-dimensional step scanning across a 96-capillary array for laser-induced fluorescence detection. 488 nm and 514 nm laser lines from the same Ar(+) laser were alternately coupled for two-color excitation in each capillary. The signal at a single photomultiplier tube is temporally sorted to distinguish among the capillaries and the excitation wavelengths. Based on the differences in absorption spectra for the dyes, the peak-height ratios in the 488 nm and 514 nm excitation electropherograms were used for peak identification for multiplexed capillary electrophoresis. Successful base calling for 24-capillary DNA sequencing was achieved to 450 bp with 99% accuracy. Advantages include the efficient utilization of light due to the high duty-cycle of step scan, good detection performance due to the reduction of stray light, ruggedness due to the small mass of the galvanometer mirror, low cost due to the simplicity of components and flexibility due to the independent paths for excitation and emission. PMID:12116160

  7. Bias Selective Operation of Sb-Based Two-Color Photodetectors

    NASA Technical Reports Server (NTRS)

    Abedin, M. N.; Refaat, Tamer F.; Bhat, Ishwara B.; Xiao, Yegao; Johnson, David G.

    2006-01-01

    Multicolor detectors have a strong potential to replace conventional single-color detectors in application dealing with the simultaneous detection of more than one wavelength. This will lead to the reduction of heavy and complex optical components now required for spectral discrimination for multi-wavelengths applications. This multicolor technology is simpler, lighter, compact and cheaper with respect to the single-color ones. In this paper, Sb-based two-color detectors fabrication and characterization are presented. The color separation is achieved by fabricating dual band pn junction on a GaSb substrate. The first band consists of an InGaAsSb pn junction for long wavelength detection, while the second band consists of a GaSb pn junction for shorter wavelength detection. Three metal contacts were deposited to access the individual junctions. Surface morphology of multi-layer thin films and also device characteristics of quasi-dual band photodetector were characterized using standard optical microscope and electro-optic techniques respectively. Dark current measurements illustrated the diode behavior of both lattice-matched detector bands. Spectral response measurements indicated either independent operation of both detectors simultaneously, or selective operation of one detector, by the polarity of the bias voltage, while serially accessing both devices.

  8. Differences in Bacterial Community Structure in Two Color Morphs of the Hawaiian Reef Coral Montipora capitata.

    PubMed

    Shore-Maggio, Amanda; Runyon, Christina M; Ushijima, Blake; Aeby, Greta S; Callahan, Sean M

    2015-10-01

    Corals harbor diverse bacterial associations that contribute to the health of the host. Using 16S rRNA pyrosequencing, we compared the bacterial communities of red and orange morphs of the Hawaiian coral Montipora capitata. Although both color morphs shared dominant bacterial genera, weighted and unweighted UniFrac analyses showed distinct bacterial communities. A single operational taxonomic unit (OTU), classified as Vibrio, represented the largest driver of differences between the color morphs. This OTU comprised 35.4% (±5.5%) of the orange morph bacterial community yet comprised 1.1% (±0.6%) of the red morph bacterial community. Cultivable bacteria from the two color morphs were also compared and tested for antibacterial activity. Cultured isolates represented 14 genera (7% of the total genera identified from sequencing data), and all but two cultured isolates had a matching OTU from the sequencing data. Half of the isolates tested (8 out of 16) displayed antibacterial activity against other cultured isolates but not against two known bacterial pathogens of M. capitata. The results from this study demonstrate that the specificity of coral-bacterial associations extends beyond the level of coral species. In addition, culture-dependent methods captured bacterial diversity that was representative of both rare and abundant members of the associated bacterial community, as characterized by culture-independent methods. PMID:26253663

  9. Exciton and Trion Valley dynamics in WSe2 measured by two-color pump-probe

    NASA Astrophysics Data System (ADS)

    Singh, Akshay; Tran, Kha; Seifert, Joe; Wang, Yiping; Scott, Marie; Pleskot, Dennis; Gabor, Nathaniel; Yan, Jiaqiang; Mandrus, David; Xu, Xiaodong; Li, Xiaoqin

    Monolayer transition metal dichalcogenides are semiconducting materials demonstrating spin-valley coupling as well as quasiparticles with large binding energies. These quasiparticles, excitons and trions (charged excitons), have quite different spin polarization properties, with the trion having larger spin lifetimes than excitons. Photoluminescence and time resolved Kerr rotation techniques have been used earlier to measure spin lifetimes. However, most of these early optical measurements have relied on non-resonant excitation conditions which tend to mask the intrinsic valley (spin) scattering properties. Here, we use circularly polarized two-color pump probe spectroscopy to measure valley (spin) polarization in monolayer WSe2 at low temperatures. We utilize quasi-resonant excitation with pump 1 meV (0.5 nm) spectrally separated from the probe, thus resulting in very efficient valley initialization. We present polarization resolved measurements on resonantly excited excitons and trions, which suggest that trions have larger spin lifetimes. Further, we probe spin polarization of trions when pumping at exciton energies, and vice-versa. We discuss the relative importance of different scattering mechanism at play. We acknowledge support from ARO and AFOSR.

  10. Coherent manipulation of cold cesium atoms in a nanofiber-based two-color dipole trap

    NASA Astrophysics Data System (ADS)

    Sayrin, Clement

    2013-05-01

    We have recently demonstrated a new experimental platform for trapping and optically interfacing laser-cooled cesium atoms. The scheme uses a two-color evanescent field surrounding an optical nanofiber to localize the atoms in a one-dimensional optical lattice 200 nm above the nanofiber surface. In order to use this fiber-coupled ensemble of trapped atoms for applications in the context of quantum communication and quantum information processing, non-classical states of the atomic spins have to be prepared and should live long enough to allow one to apply successive quantum operations. However, the close proximity of the trapped atoms to the nanofiber surface and the strong polarization gradients of nanofiber-guided light fields are potentially important sources of decoherence. In this talk, I will present our latest experimental results on characterizing the coherence properties of atomic spins in our nanofiber-based trap. Using a microwave field to drive the cesium clock transition, we determine inhomogeneous and homogeneous dephasing times by Ramsey and spin echo techniques, respectively, and identify the sources of the measured decoherence. Our results constitute the first measurement of the coherence properties of atoms trapped in the vicinity of a nanofiber and represent a fundamental step towards establishing nanofiber-based traps for cold atoms as a building block in quantum networks.

  11. Cooperative phenomena in two-pulse, two-color laser photocoagulation of cutaneous blood vessels.

    PubMed

    Barton, J K; Frangineas, G; Pummer, H; Black, J F

    2001-06-01

    A novel laser system has been developed to study the effects of multiple laser pulses of differing wavelengths on cutaneous blood vessels in vivo, using the hamster dorsal skin flap preparation and in vitro, using cuvettes of whole or diluted blood. The system permits sequenced irradiation with well-defined intrapulse spacing at 532 nm, using a long-pulse frequency-doubled Nd:YAG laser, and at 1064 nm, using a long-pulse Nd:YAG laser. Using this system, we have identified a parameter space where two pulses of different wavelengths act in a synergistic manner to effect permanent vessel damage at radiant exposures where the two pulses individually have little or no effect. Using a two-color pump-probe technique in vitro, we have identified a phenomenon we call greenlight-induced infrared absorption, where a pulse of green light causes photochemical and photothermal modifications to the chemical constituents of blood and results in enhanced infrared absorption. We identify a new chemical species, met-hemoglobin, not normally present in healthy human blood but formed during laser photocoagulation which we believe is implicated in the enhanced near-infrared absorption. PMID:11421070

  12. Two-color detector: Mercury-cadmium-telluride as a terahertz and infrared detector

    SciTech Connect

    Sizov, F.; Zabudsky, V.; Petryakov, V.; Golenkov, A.; Andreyeva, K.; Tsybrii, Z.; Dvoretskii, S.

    2015-02-23

    In this paper, issues associated with the development of infrared (IR) and terahertz (THz) radiation detectors based on HgCdTe are discussed. Two-color un-cooled and cooled to 78 K narrow-gap mercury-cadmium-telluride semiconductor thin layers with antennas were considered both as sub-THz (sub-THz) direct detection bolometers and 3–10 μm IR photoconductors. The noise equivalent power (NEP) for one of the detectors studied at ν ≈ 140 GHz reaches NEP{sub 300 K} ≈ 4.5 × 10{sup −10} W/Hz{sup 1/2} and NEP{sub 78 K} ≈ 5 × 10{sup −9} W/Hz{sup 1/2}. The same detector used as an IR photoconductor showed the responsivity at temperatures T = 78 K and 300 K with signal-to-noise ratio S/N ≈ 750 and 50, respectively, under illumination by using IR monochromator and globar as a thermal source.

  13. Differences in Bacterial Community Structure in Two Color Morphs of the Hawaiian Reef Coral Montipora capitata

    PubMed Central

    Shore-Maggio, Amanda; Runyon, Christina M.; Ushijima, Blake; Aeby, Greta S.

    2015-01-01

    Corals harbor diverse bacterial associations that contribute to the health of the host. Using 16S rRNA pyrosequencing, we compared the bacterial communities of red and orange morphs of the Hawaiian coral Montipora capitata. Although both color morphs shared dominant bacterial genera, weighted and unweighted UniFrac analyses showed distinct bacterial communities. A single operational taxonomic unit (OTU), classified as Vibrio, represented the largest driver of differences between the color morphs. This OTU comprised 35.4% (±5.5%) of the orange morph bacterial community yet comprised 1.1% (±0.6%) of the red morph bacterial community. Cultivable bacteria from the two color morphs were also compared and tested for antibacterial activity. Cultured isolates represented 14 genera (7% of the total genera identified from sequencing data), and all but two cultured isolates had a matching OTU from the sequencing data. Half of the isolates tested (8 out of 16) displayed antibacterial activity against other cultured isolates but not against two known bacterial pathogens of M. capitata. The results from this study demonstrate that the specificity of coral-bacterial associations extends beyond the level of coral species. In addition, culture-dependent methods captured bacterial diversity that was representative of both rare and abundant members of the associated bacterial community, as characterized by culture-independent methods. PMID:26253663

  14. Enhanced sensitivity in H photofragment detection by two-color reduced-Doppler ion imaging

    SciTech Connect

    Epshtein, Michael; Portnov, Alexander; Kupfer, Rotem; Rosenwaks, Salman; Bar, Ilana

    2013-11-14

    Two-color reduced-Doppler (TCRD) and one-color velocity map imaging (VMI) were used for probing H atom photofragments resulting from the ∼243.1 nm photodissociation of pyrrole. The velocity components of the H photofragments were probed by employing two counterpropagating beams at close and fixed wavelengths of 243.15 and 243.12 nm in TCRD and a single beam at ∼243.1 nm, scanned across the Doppler profile in VMI. The TCRD imaging enabled probing of the entire velocity distribution in a single pulse, resulting in enhanced ionization efficiency, as well as improved sensitivity and signal-to-noise ratio. These advantages were utilized for studying the pyrrole photodissociation at ∼243.1 and 225 nm, where the latter wavelength provided only a slight increase in the H yield over the self-signal from the probe beams. The TCRD imaging enabled obtaining high quality H{sup +} images, even for the low H photofragment yields formed in the 225 nm photolysis process, and allowed determining the velocity distributions and anisotropy parameters and getting insight into pyrrole photodissociation.

  15. Optimal design of genetic studies of gene expression with two-color microarrays in outbred crosses.

    PubMed

    Lam, Alex C; Fu, Jingyuan; Jansen, Ritsert C; Haley, Chris S; de Koning, Dirk-Jan

    2008-11-01

    Combining global gene-expression profiling and genetic analysis of natural allelic variation (genetical genomics) has great potential in dissecting the genetic pathways underlying complex phenotypes. Efficient use of microarrays is paramount in experimental design as the cost of conducting this type of study is high. For those organisms where recombinant inbred lines are available for mapping, the "distant pair design" maximizes the number of informative contrasts over all marker loci. Here, we describe an extension of this design, named the "optimal pair design," for use with F2 crosses between outbred lines. The performance of this design is investigated by simulation and compared to several other two-color microarray designs. We show that, for a given number of microarrays, the optimal pair design outperforms all other designs considered for detection of expression quantitative trait loci (eQTL) with additive effects by linkage analysis. We also discuss the suitability of this design for outbred crosses in organisms with large genomes and for detection of dominance. PMID:18791249

  16. Two-color mid-infrared thermometer using a hollow glass optical fiber

    SciTech Connect

    Small, W., IV.; Celliers, P.M.; Da Silva, L.D.; Matthews, D.L.

    1997-06-30

    A non-invasive two-color infrared thermometer has been developed for low-temperature biomedical applications. Mid-infrared radiation from the target is collected via a single 700 {mu}m-bore hollow glass optical fiber, simultaneously split into two paths and modulated by a gold-coated reflective optical chopper, and focused onto two thermoelectrically-cooled HgCdZnTe photoconductors (bandpasses of 2- 6 {mu}m and 2-12 {mu}m, respectively) by gold-coated spherical mirrors. The small numerical aperture of the hollow glass fiber provides high spatial resolution (is less than 1 mm), and the hollow bore eliminates reflective losses. The modulated detector signals are recovered using lock-in amplification, permitting measurement of small low-temperature signal buried in the background. A computer algorithm calculates the true temperature and emissivity of the target in real time based on a previous blackbody (emissivity equal to 1) calibration, taking into account reflection of the ambient radiation field from the target surface.

  17. Gradient effects on two-color soot optical pyrometry in a heavy-duty DI diesel engine

    SciTech Connect

    Musculus, Mark P.B.; Singh, Satbir; Reitz, Rolf D.

    2008-04-15

    Two-color soot optical pyrometry is a widely used technique for measuring soot temperature and volume fraction in many practical combustion devices, but line-of-sight soot temperature and volume fraction gradients can introduce significant uncertainties in the measurements. For diesel engines, these uncertainties usually can only be estimated based on assumptions about the soot property gradients along the line of sight, because full three-dimensional transient diesel soot distribution data are not available. Such information is available, however, from multidimensional computer model simulations, which are phenomenologically based, and have been validated against available in-cylinder soot measurements and diesel engine exhaust soot emissions. Using the model-predicted in-cylinder soot distributions, uncertainties in diesel two-color pyrometry data are assessed, both for a conventional high-sooting, high-temperature combustion (HTC) operating condition, and for a low-sooting, low-temperature combustion (LTC) condition. The simulation results confirm that the two-color soot measurements are strongly biased toward the properties of the hot soot. For the HTC condition, line-of-sight gradients in soot temperature span 600 K, causing relatively large errors. The two-color temperature is 200 K higher than the soot-mass-averaged value, while the two-color volume fraction is 50% lower. For the LTC condition, the two-color measurement errors are half as large as for the HTC condition, because the model-predicted soot temperature gradients along the line of sight are half as large. By contrast, soot temperature and volume fraction gradients across the field of view introduce much smaller errors of less than 50 K in temperature and 20% in volume fraction. (author)

  18. PROCEEDINGS OF A WORKSHOP ON CATALYTIC COMBUSTION (4TH) HELD AT CINCINNATI, OHIO ON MAY 14-15, 1980

    EPA Science Inventory

    The proceedings document the major presentations at the Fourth Workshop on Catalytic Combustion, held in Cincinnati, OH, May 14-15, 1980. Sponsored by the Combustion Research Branch of EPA's Industrial Environmental Research Laboratory (Research Triangle Park), the workshop serve...

  19. 75 FR 3209 - Mission Statement: U.S. Aerospace Business Development Mission to Canada, April 14-15, 2010

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-20

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE..., April 14-15, 2010 AGENCY: International Trade Administration, Department of Commerce. ACTION: Notice. Mission Description The United States Department of Commerce's International Trade Administration,...

  20. Stanford bistatic radar experiment (S-170) on Apollos 14, 15, and 16

    NASA Technical Reports Server (NTRS)

    Howard, H. T.; Tyler, G. L.

    1973-01-01

    No special equipment was placed onboard the vehicles for the bistatic radar experiments which were carried out during the lunar orbit phases of the Apollo 14, 15, and 16 flights. Radio frequency transmissions from the orbiting command service module were directed toward the moon and received on the earth after reflection from the lunar surface. Two wavelengths, 13 cm (2287.5 MHz, S-band) and 116 cm (259.7 MHz, VHF), were used. Data were obtained at the two wavelengths simultaneously during periods when the spacecraft was maneuvered to maintain a predetermined, although changing, attitude with respect to the earth and moon. Data were also obtained at the 116 cm wavelength during periods of inertial hold and SIM bay attitude maneuvers.

  1. Two-Photon Excitation STED Microscopy in Two Colors in Acute Brain Slices

    PubMed Central

    Bethge, Philipp; Chéreau, Ronan; Avignone, Elena; Marsicano, Giovanni; Nägerl, U. Valentin

    2013-01-01

    Many cellular structures and organelles are too small to be properly resolved by conventional light microscopy. This is particularly true for dendritic spines and glial processes, which are very small, dynamic, and embedded in dense tissue, making it difficult to image them under realistic experimental conditions. Two-photon microscopy is currently the method of choice for imaging in thick living tissue preparations, both in acute brain slices and in vivo. However, the spatial resolution of a two-photon microscope, which is limited to ∼350 nm by the diffraction of light, is not sufficient for resolving many important details of neural morphology, such as the width of spine necks or thin glial processes. Recently developed superresolution approaches, such as stimulated emission depletion microscopy, have set new standards of optical resolution in imaging living tissue. However, the important goal of superresolution imaging with significant subdiffraction resolution has not yet been accomplished in acute brain slices. To overcome this limitation, we have developed a new microscope based on two-photon excitation and pulsed stimulated emission depletion microscopy, which provides unprecedented spatial resolution and excellent experimental access in acute brain slices using a long-working distance objective. The new microscope improves on the spatial resolution of a regular two-photon microscope by a factor of four to six, and it is compatible with time-lapse and simultaneous two-color superresolution imaging in living cells. We demonstrate the potential of this nanoscopy approach for brain slice physiology by imaging the morphology of dendritic spines and microglial cells well below the surface of acute brain slices. PMID:23442956

  2. One- and Two-Color Resonant Photoionization Spectroscopy of Chromium-Doped Helium Nanodroplets

    PubMed Central

    2014-01-01

    We investigate the photoinduced relaxation dynamics of Cr atoms embedded into superfluid helium nanodroplets. One- and two-color resonant two-photon ionization (1CR2PI and 2CR2PI, respectively) are applied to study the two strong ground state transitions z7P2,3,4° ← a7S3 and y7P2,3,4° ← a7S3. Upon photoexcitation, Cr* atoms are ejected from the droplet in various excited states, as well as paired with helium atoms as Cr*–Hen exciplexes. For the y7P2,3,4° intermediate state, comparison of the two methods reveals that energetically lower states than previously identified are also populated. With 1CR2PI we find that the population of ejected z5P3° states is reduced for increasing droplet size, indicating that population is transferred preferentially to lower states during longer interaction with the droplet. In the 2CR2PI spectra we find evidence for generation of bare Cr atoms in their septet ground state (a7S3) and metastable quintet state (a5S2), which we attribute to a photoinduced fast excitation–relaxation cycle mediated by the droplet. A fraction of Cr atoms in these ground and metastable states is attached to helium atoms, as indicated by blue wings next to bare atom spectral lines. These relaxation channels provide new insight into the interaction of excited transition metal atoms with helium nanodroplets. PMID:24708058

  3. Dynamics of surface thermal expansion and diffusivity using two-color reflection transient gratings

    SciTech Connect

    Pennington, D.M.; Harris, C.B.

    1993-02-01

    We report ultrafast measurements of the dynamic thermal expansion of a surface and the temperature dependent surface thermal diffusivity using a two-color reflection transient grating technique. Studies were performed on p-type, n-type, and undoped GaAs(100) samples at several temperatures. Using a 75 fs ultraviolet probe with visible excitation beams, the electronic effects that dominate single color experiments become negligible; thus surface expansion due to heating and the subsequent contraction caused by cooling provide the dominant influence on the diffracted probe. The diffracted signal was composed of two components, thermal expansion of the surface and heat flow away from the surface, allowing the determination of the rate of expansion as well as the surface thermal diffusivity. At room temperature a signal rise due to thermal expansion was observed, corresponding to a maximum average displacement of {approx} 1 {angstrom} at 32 ps. Large fringe spacings were used, thus the dominant contributions to the signal were expansion and diffusion perpendicular to the surface. Values for the surface thermal diffusivity of GaAs were measured and found to be in reasonable agreement with bulk values above 50{degrees}K. Below 50{degrees}K, the diffusivity at the surface was more than an order of magnitude slower than in the bulk due to increased phonon boundary scattering. Comparison of the results with a straightforward thermal model yields good agreement over a range of temperatures (12--300{degrees}K). The applicability and advantages of the transient grating technique for studying photothermal and photoacoustic phenomena are discussed.

  4. Electrical and optical characteristics of two color mid wave HgCdTe infrared detectors

    NASA Astrophysics Data System (ADS)

    Mason, Whitney; Waterman, J. R.

    1999-03-01

    Two-color mid wave triple-layer heterojunction HgCdTe detectors were studied using temperature-dependent current-voltage (I-V) measurements, temperature-dependent spectral response measurements, and temperature-dependent noise measurements. The reverse biased dark current shows diffusion-limited behavior for T>125 K. The same data show evidence for generation-recombination-type behavior for the longer wavelength junction at temperatures between 100 and 125 K. For temperatures less than 100 K, the measurements are background limited by photon flux, even though these measurements are performed at nominal zero background. The upper junction shows soft reverse breakdown voltages on the order of about 250 mV, while the bottom junction shows no breakdown for V<500 mV. At 80 K, the R0A product is in excess of 1×106 Ω cm2. In forward bias, the current-voltage characteristics of the lower junction are diffusion limited for all temperatures, while at lower temperatures, the upper junction showed generation-recombination behavior. Optical measurements found a cutoff wavelength of about 4 μm for the lower junction and about 4.5 μm for the upper junction. The spectral crosstalk was less than 3%. At 80 K, the frequency-dependent noise of the shorter wavelength junction showed no dependence on bias, while for the longer wavelength junction, the noise at lower frequencies increased with bias. There is no difference in the noise characteristics when either the photon flux or the temperature is increased.

  5. Countermeasure effectiveness against a man-portable air-defense system containing a two-color spinscan infrared seeker

    NASA Astrophysics Data System (ADS)

    Jackman, James; Richardson, Mark; Butters, Brian; Walmsley, Roy

    2011-12-01

    Man-portable air-defense (MANPAD) systems have developed sophisticated counter-countermeasures (CCM) to try and defeat any expendable countermeasure that is deployed by an aircraft. One of these is a seeker that is able to detect in two different parts of the electromagnetic spectrum. Termed two-color, the seeker can compare the emissions from the target and a countermeasure in different wavebands and reject the countermeasure. In this paper we describe the modeling process of a two-color infrared seeker using COUNTERSIM, a missile engagement and countermeasure software simulation tool. First, the simulations model a MANPAD with a two-color CCM which is fired against a fast jet model and a transport aircraft model releasing reactive countermeasures. This is then compared to when the aircraft releases countermeasures throughout an engagement up to the hit point to investigate the optimum flare firing time. The results show that the release time of expendable decoys as a countermeasure against a MANPAD with a two-color CCM is critical.

  6. Digitized POSS-II: Galaxy Number Counts in Two Colors Over a Multi-Plate Region

    NASA Astrophysics Data System (ADS)

    Weir, N.; Djorgovski, S.; Fayyad, U.

    1993-05-01

    We have developed a software system for the reduction and analysis of the Palomar-STScI Digital Sky Survey (cf. B.A.A.S. 23, p. 1434, and B.A.A.S. 24, pp. 741, 750, and 1139). This system, named SKICAT, uses a number of image processing and machine-learning based modules, and conducts pipeline processing of the plate scans, from raw pixel measurement, object classification, photometric matching of multiple plate images, to high-level catalog database manipulation using an X-windows based GUI. We are now in the process of implementing a variety of tools for the scientific and multivariate statistical analysis of the object catalogs. We will present our initial results on galaxy and star counts in two colors (photographic J and F, calibrated to Gunn g and r bands), for a multi-plate region near the north Galactic pole, covering up to 5 Survey fields ( ~ 125 square degrees), and up to 11 Survey fields ( ~ 275 square degrees) in a single color. The data have been uniformly calibrated using CCD sequences and plate overlaps over the range 16 < r < 20, within which we are over 90% complete. We also performed extensive tests to assure the accuracy of automatic galaxy classifications over this magnitude range. Previous results from the southern APM Survey implied dramatic evolution of galaxies at low redshift. We will present our new galaxy counts as function of magnitudes colors in the context of these measurements and galaxy evolution models. Acknowledgements: The POSS-II is partially funded by grants to Caltech from the Eastman Kodak Co., the National Geographic Society, the Samuel Oschin Foundation, the NSF grants AST 84-08225 and AST 87-19465, and the NASA grants NGL 05002140 and NAGW 1710. NW was supported in part by a NSF graduate fellowship and by IPAC. SD acknowledges a partial support from the NASA contract NAS5-31348, the NSF PYI award AST-9157412, the Caltech President's fund, and JPL. Work at JPL is performed under a contract with the NASA.

  7. First-principles study of hypothetical boron crystals: Bn(n = 13, 14, 15)

    NASA Astrophysics Data System (ADS)

    Aydın, Sezgin; Şimşek, Mehmet

    2012-11-01

    First-principles simulations within density functional theory are performed to investigate structural, electronic and mechanical properties of hypothetical boron crystals Bn(n = 13, 14, 15). These hypothetical crystals are generated by inserting boron atom(s) to the space in three-dimensional network of α-boron (α-B12). The effects of inserted atom(s) and their site(s) on the lattice parameters, mechanical and electronic properties are discussed. Cohesive energies and formation enthalpies are calculated to discuss energetic stability of purposed compounds, and also the elastic constants are determined to study mechanical stability and mechanical properties such as bulk, shear and Young moduli. To check the phase stability, molecular dynamics simulations and transition state search calculations are performed and to emphasize distinction of the phases energy-volume curves for all phases are presented. From calculated density of states and Mulliken atomic charges/bond overlap populations, it is observed that the charge transfers exist between inserted boron atom(s) located at different sites and icosahedral boron atoms. By mean of the optimized ground state geometry and other first-principles results, the micro-hardnesses of each boron phases are calculated.

  8. Low-Latitude Auroras: The Magnetic Storm of 14-15 May 1921

    NASA Technical Reports Server (NTRS)

    Silverman, S. M.; Cliver, E. W.

    2001-01-01

    We review solar geophysical data relating to the great magnetic storm of 14-15 May 1921, with emphasis on observations of the low-latitude visual aurora. From the reports we have gathered for this event the lowest geomagnetic latitude of definite overhead aurora (coronal form) was 40 deg and the lowest geomagnetic latitude from which auroras were observed on the poleward horizon in the northern hemisphere was 30 deg. For comparison, corresponding overhead/low-latitude values of 48 deg/32 deg and 41 deg/20 deg were reported for the great auroras on 28-29 August and 1-2 September 1859, respectively. However for the 1921 event, there is a report of aurora from Apia, Samoa, in the southern hemisphere, within 13 deg of the geomagnetic equator. This report by professional observers appears to be credible, based on the aurora description and timing, but is puzzling because of the discrepancy with the lowest latitude of observation in the northern hemisphere and the great implied aurora height (approximately 2000 km, assuming overhead aurora at Auckland, New Zealand). We discuss various possibilities that might account for this observation.

  9. Human platelets produce 14,15-oxido-5,8,11-eicosatrienoic acid from phosphatidylinositol

    SciTech Connect

    Ballou, L.R.; Lam, B.K.; Wong, P.Y.K.; Cheung, W.Y.

    1987-05-01

    Human platelets contain a soluble enzyme or enzyme system which catalyzes the formation of a compound more polar than arachidonate from 2-arachidonyl-sn-phosphatidylinositol (PtdIns). The C-value and mass spectrum of the compound appears similar to the reported values of 14,15-oxido-5,8,11-eicosatrienoic acid (EET). 2-Arachidonyl-sn-phosphatidylcholine, 2-arachidonyl-sn-phosphatidylethanolamine and arachidonic acid were not substrates for EET production. The reaction was Ca/sup 2 +/-dependent and insensitive to aspirin, mepacrin and indomethacin. EET formation was greatly reduced under nitrogen or carbon monoxide, however, exposure to atmospheric air rapidly restored EET production to a rate comparable to that under air. Further, neither NADPH nor cyanide affected EET formation, suggesting that a cytochrome P-450 system was not involved. Intact platelets prelabeled with (/sup 14/C)arachidonic acid generated at least 0.5 nmole of EET/10/sup 9/ platelets in response to thrombin; other agonists such as collagen, epinephrine, ADP or ionophore A23187 were not effective. Collectively, these data suggest that human platelets possess an enzyme system which appears to catalyze epoxidation of the arachidonyl moiety of PtdIns and its subsequent hydrolysis to yield EET.

  10. Hearing and loud music exposure in 14-15 years old adolescents.

    PubMed

    Serra, Mario R; Biassoni, Ester C; Hinalaf, María; Abraham, Mónica; Pavlik, Marta; Villalobo, Jorge Pérez; Curet, Carlos; Joekes, Silvia; Yacci, María R; Righetti, Andrea

    2014-01-01

    Adolescent exposure to loud music has become a social and health problem whose study demands a holistic approach. The aims of the current study are: (1) To detect early noise-induced hearing loss among adolescents and establish its relationship with their participation in musical recreational activities and (2) to determine sound immission levels in nightclubs and personal music players (PMPs). The participants consisted in 172 14-15 years old adolescents from a technical high school. Conventional and extended high frequency audiometry, transient evoked otoacoustic emissions and questionnaire on recreational habits were administered. Hearing threshold levels (HTLs) were classified as: normal (Group 1), slightly shifted (Group 2), and significantly shifted (Group 3). The musical general exposure (MGE), from participation in recreational musical activities, was categorized in low, moderate, and high exposure. The results revealed an increase of HTL in Group 2 compared with Group 1 (P < 0.01), in Group 3 compared with Group 2 (P < 0.05) only in extended high frequency range, in Group 3 compared with Group 1 (P < 0.01). Besides, a decrease in mean global amplitude, reproducibility and in frequencies amplitude in Group 2 compared with Group 1 (P < 0.05) and in Group 3 compared with Group 1 (P < 0.05). A significant difference (P < 0.05) was found in Group 1's HTL between low and high exposure, showing higher HTL in high exposure. The sound immission measured in nightclubs (107.8-112.2) dBA and PMPs (82.9-104.6) dBA revealed sound levels risky for hearing health according to exposure times. It demonstrates the need to implement preventive and hearing health promoting actions in adolescents. PMID:25209042

  11. Interaction Between Two CMEs During 14 - 15 February 2011 and Their Unusual Radio Signature

    NASA Astrophysics Data System (ADS)

    Shanmugaraju, A.; Prasanna Subramanian, S.; Vrsnak, Bojan; Ibrahim, M. Syed

    2014-12-01

    We report a detailed analysis of an interaction between two coronal mass ejections (CMEs) that were observed on 14 - 15 February 2011 and the corresponding radio enhancement, which was similar to the "CME cannibalism" reported by Gopalswamy et al. ( Astrophys. J. 548, L91, 2001). A primary CME, with a mean field-of-view velocity of 669 km s-1 in the Solar and Heliospheric Observatory (SOHO)/ Large Angle Spectrometric Coronagraph (LASCO), was more than as twice as fast as the slow CME preceding it (326 km s-1), which indicates that the two CMEs interacted. A radio-enhancement signature (in the frequency range 1 MHz - 400 kHz) due to the CME interaction was analyzed and interpreted using the CME data from LASCO and from the Solar Terrestrial Relations Observatory (STEREO) HI-1, radio data from Wind/ Radio and Plasma Wave Experiment (WAVES), and employing known electron-density models and kinematic modeling. The following results are obtained: i) The CME interaction occurred around 05:00 - 10:00 UT in a height range 20 - 25 R⊙. An unusual radio signature is observed during the time of interaction in the Wind/WAVES dynamic radio spectrum. ii) The enhancement duration shows that the interaction segment might be wider than 5 R⊙. iii) The shock height estimated using density models for the radio enhancement region is 10 - 30 R⊙. iv) Using kinematic modeling and assuming a completely inelastic collision, the decrease of kinetic energy based on speeds from LASCO data is determined to be 0.77×1023 J, and 3.67×1023 J if speeds from STEREO data are considered. vi) The acceleration, momentum, and force are found to be a=-168 m s-2, I=6.1×1018 kg m s-1, and F=1.7×1015 N, respectively, using STEREO data.

  12. Coherent control of the dissociation probability of H2+ in ω-3ω two-color fields

    NASA Astrophysics Data System (ADS)

    Xu, Han; Hu, Hongtao; Tong, Xiao-Min; Liu, Peng; Li, Ruxin; Sang, Robert T.; Litvinyuk, Igor V.

    2016-06-01

    We demonstrate that the coherent control of unimolecular reactions by using a waveform-controlled laser fields can lead to a strong modulation on the yield of the reaction. By using a synthesized ω (1800-nm) and 3ω (600-nm) two-color laser field, the probability of photodissociation of H2+ can be strongly modulated by varying the relative phase between the two colors. The dissociation probability maximizes at different relative phases for protons with different kinetic energy, and such energy dependence can also be qualitatively reproduced by our simulation. We attribute the observed dissociation probability modulation to the interference between two different dissociation pathways which start from the same electronic states and end with the same kinetic energy.

  13. Two-color, rolling-circle amplification on antibody microarrays for sensitive, multiplexed serum-protein measurements.

    PubMed

    Zhou, Heping; Bouwman, Kerri; Schotanus, Mark; Verweij, Cornelius; Marrero, Jorge A; Dillon, Deborah; Costa, Jose; Lizardi, Paul; Haab, Brian B

    2004-01-01

    The ability to conveniently and rapidly profile a diverse set of proteins has valuable applications. In a step toward further enabling such a capability, we developed the use of rolling-circle amplification (RCA) to measure the relative levels of proteins from two serum samples, labeled with biotin and digoxigenin, respectively, that have been captured on antibody microarrays. Two-color RCA produced fluorescence up to 30-fold higher than direct-labeling and indirect-detection methods using antibody microarrays prepared on both polyacrylamide-based hydrogels and nitrocellulose. Replicate RCA measurements of multiple proteins from sets of 24 serum samples were highly reproducible and accurate. In addition, RCA enabled reproducible measurements of distinct expression profiles from lower-abundance proteins that were not measurable using the other detection methods. Two-color RCA on antibody microarrays should allow the convenient acquisition of expression profiles from a great diversity of proteins for a variety of applications. PMID:15059261

  14. Detection of Ultracold Ground-State Molecules by One- and Two-Color Resonance-Enhanced Two-Photon Ionization

    NASA Astrophysics Data System (ADS)

    Li, Zhonghao; Ji, Zhonghua; Zhang, Xiang; Yuan, Jinpeng; Zhao, Yanting; Xiao, Liantuan; Jia, Suotang

    2016-08-01

    One- and two-color resonance-enhanced two-photon ionization (RETPI) is used to detect ultracold ground-state RbCs molecules which are formed via short-range photoassociation from laser-cooled atoms. The transition from the X1Σ+(v = 0) state to the 21Π(v = 10) state of ultracold RbCs molecules shows the consistence of one- and two-color RETPI. A multi-photon photoionization rate model is introduced to interpret the dependence of molecular ion intensity on photoionized laser energy, and can be used to verify the photoionization scheme. This photoionization rate model can be expanded to multi-color photoionization for all kinds of atoms and molecules, which is a powerful method of determining the photoionization scheme.

  15. Nanometer resolved single-molecule colocalization of nuclear factors by two-color super resolution microscopy imaging.

    PubMed

    Georgieva, Mariya; Cattoni, Diego I; Fiche, Jean-Bernard; Mutin, Thibaut; Chamousset, Delphine; Nollmann, Marcelo

    2016-08-01

    In order to study the detailed assembly and regulation mechanisms of complex structures and machineries in the cell, simultaneous in situ observation of all the individual interacting components should be achieved. Multi-color Single-Molecule Localization Microscopy (SMLM) is ideally suited for these quantifications. Here, we build on previous developments and thoroughly discuss a protocol for two-color SMLM combining PALM and STORM, including sample preparation details, image acquisition and data postprocessing analysis. We implement and evaluate a recently proposed colocalization analysis method (aCBC) that allows single-molecule colocalization quantification with the potential of revealing fine, nanometer-scaled, structural details of multicomponent complexes. Finally, using a doubly-labeled nuclear factor (Beaf-32) in Drosophila S2 cells we experimentally validate the colocalization quantification algorithm, highlight its advantages and discuss how using high molecular weight fluorescently labeled tags compromises colocalization precision in two-color SMLM experiments. PMID:27045944

  16. Saturation curves of two-color laser-induced incandescence measurements for the investigation of soot optical properties

    NASA Astrophysics Data System (ADS)

    Migliorini, F.; De Iuliis, S.; Maffi, S.; Zizak, G.

    2015-09-01

    Two-color laser-induced incandescence (LII) measurements are carried out in diffusion flames and at the exhaust of a homemade soot generator, both fueled with ethylene and methane. Two-color prompt LII signals, their ratio and the corresponding temperature have been analyzed as a function of laser fluence. In particular, the effect of fuel, soot load and gas/particle initial temperature on LII measurements have been investigated. LII spectral measurements have also been performed in all conditions for validation. The results suggest that the incandescence is sensitive to both optical and non-optical physical properties of the particles. Moreover, soot volume fraction measurements are dependent on the laser fluence used, indicating that the soot temperature influences the refractive index absorption function. Such issues can be overcome by working at high laser fluences, where the saturation curves are independent from the experimental conditions if the soot absorption function near soot sublimation threshold is known.

  17. Parity-selective enhancement of field-free molecular orientation in an intense two-color laser field

    SciTech Connect

    Yun, Hyeok; Nam, Chang Hee; Kim, Hyung Taek; Kim, Chul Min; Lee, Jongmin

    2011-12-15

    We investigated the characteristics of molecular orientation induced by a nonresonant two-color femtosecond laser field. By analyzing the rotational dynamics of asymmetric linear molecules, we revealed that the critical parameter in characterizing the molecular orientation was the hyperpolarizability of molecules that selected the excitation paths of rotational states between parity-changing and parity-conserving transitions. Especially, in the case of molecules with small hyperpolarizability, a significant enhancement of orientation was achieved at the half-rotational period, instead of the full-rotational period. This deeper understanding of the hyperpolarizability-dependent characteristics of molecular orientation in a two-color scheme can provide an effective method to achieve significantly enhanced field-free orientation for various polar molecules.

  18. Off-Axis Phase-Matched Terahertz Emission from Two-Color Laser-Induced Plasma Filaments

    NASA Astrophysics Data System (ADS)

    You, Y. S.; Oh, T. I.; Kim, K. Y.

    2012-11-01

    We observe off-axis phase-matched terahertz generation in long air-plasma filaments produced by femtosecond two-color laser focusing. Here, phase matching naturally occurs due to off-axis constructive interference between locally generated terahertz waves, and this determines the far-field terahertz radiation profiles and yields. For a filament longer than the characteristic two-color dephasing length, it emits conical terahertz radiation in the off-axis direction, peaked at 4-7° depending on the radiation frequencies. The total terahertz yield continuously increases with the filament length, well beyond the dephasing length. The phase-matching condition observed here provides a simple method for scalable terahertz generation in elongated plasmas.

  19. High-accuracy self-correction of refractive index of air using two-color interferometry of optical frequency combs.

    PubMed

    Minoshima, Kaoru; Arai, Kaoru; Inaba, Hajime

    2011-12-19

    Long-path pulse-to-pulse interferometers of two-color frequency combs are developed using fundamental and second harmonics of a mode-locked fiber laser. Interferometric phase difference between two-color frequency combs was precisely measured by stabilizing the fundamental fringe phase by controlling the repetition frequency of the comb, and a stability of 10(-10) for 1000 s was achieved in the measurement of an optical path length difference between two wavelengths. In long-term measurements performed for 10 h, results of phase variation of interferometric measurements were highly consistent with the fluctuations in the calculated difference of refractive indices of air at two wavelengths with an accuracy of 10(-10). The difference between the measured optical distances corresponding to two wavelengths and the optical distance corresponding to the fundamental wavelength were used in the two-color method; high-accuracy self-correction of the fluctuation of refractive index of air was performed with an uncertainty of 5 × 10(-8) for 10-h measurements when the maximum refractive index change was on the order of 10(-6). PMID:22274198

  20. Greater than two orders of magnitude enhancement of high-order harmonic generation driven by two-color laser fields

    NASA Astrophysics Data System (ADS)

    Severt, T.; Troß, J.; Timilisina, P.; Kolliopoulos, G.; Buczek, S.; Trallero-Herrero, C.; Ben-Itzhak, I.

    2016-05-01

    In the past decade, there has been a drive to produce intense tabletop XUV laser sources to study ultrafast dynamics in atoms and molecules. One promising technique is high-order harmonic generation (HHG) driven by two-color laser fields, which has been shown to enhance the harmonic yield over harmonics generated by only the fundamental single-color field, depending on the wavelengths' relationship. In preliminary data, we observe more than two orders of magnitude enhancement of harmonics produced by the two-color (800/400-nm) laser field over the 800-nm field. We also explore the enhancement's dependence on the relative intensities between the two colors. This work and T.S. are partially supported by the National Science Foundation under Award No. IIA-1430493. JRML personnel and operations are funded by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office for Science, U.S. Department of Energy. S.B. was also supported by NSF-REU program Grant No. PHYS-1461251.

  1. Micronized-Coal Burner Facility

    NASA Technical Reports Server (NTRS)

    Calfo, F. D.; Lupton, M. W.

    1986-01-01

    Micronized-coal (coal-in-oil mix) burner facility developed to fulfill need to generate erosion/corrosion data on series of superalloy specimens. In order to successfully operate gas turbine using COM, two primary conditions must be met. First, there must be adequate atomization of COM and second, minimization of coking of burner. Meeting these conditions will be achieved only by clean burning and flame stability.

  2. Coherent control of D2/H2 dissociative ionization by a mid-infrared two-color laser field

    NASA Astrophysics Data System (ADS)

    Wanie, Vincent; Ibrahim, Heide; Beaulieu, Samuel; Thiré, Nicolas; Schmidt, Bruno E.; Deng, Yunpei; Alnaser, Ali S.; Litvinyuk, Igor V.; Tong, Xiao-Min; Légaré, François

    2016-01-01

    Steering the electrons during an ultrafast photo-induced process in a molecule influences the chemical behavior of the system, opening the door to the control of photochemical reactions and photobiological processes. Electrons can be efficiently localized using a strong laser field with a well-designed temporal shape of the electric component. Consequently, many experiments have been performed with laser sources in the near-infrared region (800 nm) in the interest of studying and enhancing the electron localization. However, due to its limited accessibility, the mid-infrared (MIR) range has barely been investigated, although it allows to efficiently control small molecules and even more complex systems. To push further the manipulation of basic chemical mechanisms, we used a MIR two-color (1800 and 900 nm) laser field to ionize H2 and D2 molecules and to steer the remaining electron during the photo-induced dissociation. The study of this prototype reaction led to the simultaneous control of four fragmentation channels. The results are well reproduced by a theoretical model solving the time-dependent Schrödinger equation for the molecular ion, identifying the involved dissociation mechanisms. By varying the relative phase between the two colors, asymmetries (i.e., electron localization selectivity) of up to 65% were obtained, corresponding to enhanced or equivalent levels of control compared to previous experiments. Experimentally easier to implement, the use of a two-color laser field leads to a better electron localization than carrier-envelope phase stabilized pulses and applying the technique in the MIR range reveals more dissociation channels than at 800 nm.

  3. Systematic experimental study on a highly efficient terahertz source based on two-color laser-induced air plasma

    NASA Astrophysics Data System (ADS)

    Xie, Jun; Fan, Wen-Hui; Chen, Xu

    2016-05-01

    In this paper, highly efficient terahertz radiation generated by two-color femtosecond laser-induced air plasma is reported. A number of variables that can obviously influence terahertz generation and detection have been investigated systematically. The dependence on experimental parameters, including pulse energy, the rotation angle of beta-barium boron oxide (BBO) crystal, the distance between BBO crystal and laser-induced plasma, focal length, chopper frequency, and detection angle are presented, and the optimal values of these parameters have also been obtained experimentally. Finally, a highly efficient terahertz source has been achieved and can be utilized to carry out further investigation on terahertz sensing, spectroscopy, and imaging.

  4. A Two Colorable Fourth Order Compact Difference Scheme and Parallel Iterative Solution of the 3D Convection Diffusion Equation

    NASA Technical Reports Server (NTRS)

    Zhang, Jun; Ge, Lixin; Kouatchou, Jules

    2000-01-01

    A new fourth order compact difference scheme for the three dimensional convection diffusion equation with variable coefficients is presented. The novelty of this new difference scheme is that it Only requires 15 grid points and that it can be decoupled with two colors. The entire computational grid can be updated in two parallel subsweeps with the Gauss-Seidel type iterative method. This is compared with the known 19 point fourth order compact differenCe scheme which requires four colors to decouple the computational grid. Numerical results, with multigrid methods implemented on a shared memory parallel computer, are presented to compare the 15 point and the 19 point fourth order compact schemes.

  5. Observations of strain accumulation across the San Andreas fault near Palmdale, California, with a two-color geodimeter

    USGS Publications Warehouse

    Langbein, J.O.; Linker, M.F.; McGarr, A.; Slater, L.E.

    1982-01-01

    Two-color laser ranging measurements during a 15-month period over a geodetic network spanning the San Andreas fault near Palmdale, California, indicate that the crust expands and contracts aseismically in episodes as short as 2 weeks. Shear strain parallel to the fault has accumulated monotonically since November 1980, but at a variable rate. Improvements in measurement precision and temporal resolution over those of previous geodetic studies near Palmdale have resulted in the definition of a time history of crustal deformation that is much more complex than formerly realized. Copyright ?? 1982 AAAS.

  6. Probe of the electron correlation in sequential double ionization of helium by two-color attosecond pulses

    NASA Astrophysics Data System (ADS)

    Peng, Liang-You; Zhang, Zheng; Jiang, Wei-Chao; Zhang, Gong-Qiu; Gong, Qihuang

    2012-12-01

    We theoretically study the sequential double ionization of He by two-color attosecond pulses. We show that, for short time delays between the two pulses, the ionization spectra cannot be explained by an independent model based on the time-dependent perturbation theory. By varying the time delay, one can probe the role of the electron correlation played in the double ionization, which is mostly obvious by examining the differential double-ionization yield. In the present scheme, we also identify a kind of “catch-up” interaction between the two ionized electrons.

  7. Enhanced high-order-harmonic generation and wave mixing via two-color multiphoton excitation of atoms and molecules

    NASA Astrophysics Data System (ADS)

    Avetissian, H. K.; Avchyan, B. R.; Mkrtchian, G. F.

    2016-07-01

    We consider harmonics generation and wave mixing by two-color multiphoton resonant excitation of three-level atoms and molecules in strong laser fields. The coherent part of the spectra corresponding to multicolor harmonics generation is investigated. The obtained analytical results on the basis of a generalized rotating wave approximation are in a good agreement with numerical calculations. The results applied to the hydrogen atoms and homonuclear diatomic molecular ions show that one can achieve efficient generation of moderately high multicolor harmonics via multiphoton resonant excitation by appropriate laser pulses.

  8. Two color laser fields for studying the Cooper minimum with phase-matched high-order harmonic generation

    SciTech Connect

    Ba Dinh, Khuong Vu Le, Hoang; Hannaford, Peter; Van Dao, Lap

    2014-05-28

    We experimentally study the observation of the Cooper minimum in a semi-infinite argon-filled gas cell using two-color laser fields at wavelengths of 1400 nm and 800 nm. The experimental results show that the additional 800 nm field can change the macroscopic phase-matching condition through change of the atomic dipole phase associated with the electron in the continuum state and that this approach can be used to control the appearance of the Cooper minimum in the high-order harmonic spectrum in order to study the electronic structure of atoms and molecules.

  9. Observations of strain accumulation across the san andreas fault near palmdale, california, with a two-color geodimeter.

    PubMed

    Langbein, J O; Linker, M F; McGarr, A; Slater, L E

    1982-12-17

    Two-color laser ranging measurements during a 15-month period over a geodetic network spanning the San Andreas fault near Palmdale, California, indicate that the crust expands and contracts aseismically in episodes as short as 2 weeks. Shear strain parallel to the fault has accumulated monotonically since November 1980, but at a variable rate. Improvements in measurement precision and temporal resolution over those of previous geodetic studies near Palmdale have resulted in the definition of a time history of crustal deformation that is much more complex than formerly realized. PMID:17802470

  10. High Energy 2-micron Laser Developments

    NASA Technical Reports Server (NTRS)

    Yu, Jirong; Trieu, Bo C.; Petros, Mulugeta; Bai, Yingxin; Petzar, Paul J.; Koch, Grady J.; Singh, Upendra N.; Kavaya, Michael J.

    2007-01-01

    This viewgraph presentation shows the development of 2-micron solid state lasers. The topics covered include: 1) Overview 2-micron solid state lasers; 2) Modeling and population inversion measurement; 3) Side pump oscillator; and 4) One Joule 2-m Laser.

  11. Dynamics of the magnetosphere during geomagnetic storms on January 21-22, 2005 and December 14-15, 2006

    NASA Astrophysics Data System (ADS)

    Kalegaev, V. V.; Vlasova, N. A.; Peng, Z.

    2015-03-01

    The dynamics of large-scale magnetospheric current systems during geomagnetic storms on January 21-22, 2005 and December 14-15, 2006 is investigated using the A2000 model of the magnetospheric magnetic field. Storm development is controlled by both the interplanetary magnetic field and solar wind pressure that create conditions for injection of plasma into the inner magnetosphere. It is demonstrated that the main role in the development of the January 21-22, 2005 magnetic storm was played by a strong impulse of solar wind pressure, while the December 14-15, 2006 storm was initiated by a changed orientation of the interplanetary magnetic field. As a consequence, the Dst variation of the geomagnetic field during the January 21-22, 2005 storm is determined basically by ring current development. On December 14-15, 2006 it is determined by comparable contributions of the ring current and of the magnetotail currents. The results of modeling are confirmed by data on dynamic properties of the fluxes of three populations of ions with energies 30-80 keV (at low latitudes L < 2, and at latitudes below and above the isotropic precipitation boundary) measured by the solar-synchronous satellites of NOAA ( POES 15, POES 16, and POES 17).

  12. A Case of Acute Myeloid Leukemia with a Previously Unreported Translocation (14; 15) (q32; q13).

    PubMed

    Khawandanah, Mohamad; Gehrs, Bradley; Li, Shibo; Holter Chakrabarty, Jennifer; Cherry, Mohamad

    2014-01-01

    Background. We hereby describe what we believe to be the first reported case of t (14; 15) (q32; q13) associated with acute myeloid leukemia (AML). Methods. PubMed, Embase, and OVID search engines were used to review the related literature and similar published cases. Case. A47-year-old female presented in December 2011 with AML (acute myelomonocytic leukemia) with normal cytogenetics; molecular testing revealed FLT-3 internal tandem duplication (ITD) mutation, while no mutations involving FLT3 D385/I836, NPM1 exon 12, or KIT exons 8 and 17 were detected. She was induced with 7 + 3 (cytarabine + idarubicin) and achieved complete remission after a second induction with high-dose cytarabine (HiDAC) followed by uneventful consolidation. She presented 19 months after diagnosis with relapsed disease. Of note, at relapse cytogenetic analysis revealed t (14; 15) (q32; q13), while FLT-3 analysis showed a codon D835 mutation (no ITD mutation was detected). She proved refractory to the initial clofarabine-based regimen, so FLAG-idarubicin then was used. She continued to have persistent disease, and she was discharged on best supportive care. Conclusion. Based on this single case of AML with t (14; 15) (q32; q13), this newly reported translocation may be associated with refractory disease. PMID:25436161

  13. Dynamic image correlation spectroscopy (ICS) and two-color image cross-correlation spectroscopy (ICCS): concepts and application

    NASA Astrophysics Data System (ADS)

    Wiseman, Paul W.; Squier, Jeffrey A.; Wilson, Kent R.

    2000-05-01

    The interaction of macromolecules in space and time are known to be important for the regulation of many biochemical reactions. Image correlation spectroscopy (ICS) was recently introduced as an imaging analog of fluorescence correlation spectroscopy optimized for measuring the aggregation state of fluorescently labeled macromolecules on the surface of biological cells. We present two novel developments of dynamic ICS that will greatly enhance our abilities to measure molecular interactions as a function of time and space in living cells. We illustrate the use of a rapid scan two-photon microscope system to collect image series at high time resolution (30 frames/s) for dynamic ICS analysis. Secondly, we demonstrate the implementation of two-color image cross-correlation spectroscopy (ICCS) with a CLSM using multiple wavelength excitation, and with two-photon excitation of samples containing two different fluorescent species. Cross-correlation analysis allows the degree of co- localization of two different fluorophores to be measured directly. By performing two-color ICCS, we can monitor the interactions of non-identical labeled macromolecules as a function of time and space. We describe the experimental setup for both methods and illustrate the application for measurements of the diffusion coefficients of singly and doubly labeled fluorescent microspheres in aqueous solutions.

  14. Controlling continuum wavepacket interference by two-color laser field in over-the-barrier ionization regime

    NASA Astrophysics Data System (ADS)

    Zhou, Sheng-Peng; Yang, Yu-Jun; Ding, Da-Jun

    2016-02-01

    Continuum wavepacket interference is investigated by numerically solving the time-dependent Schrödinger equation for the interaction of hydrogen atoms with laser fields. The obtained wavepacket evolution indicates that, in the over-the-barrier ionization regime (1016 W/cm2), the continuum-continuum (CC) interference of ionizing electrons becomes the main process in highorder harmonics generation (HHG), compared with continuum-bound (CB) transition, as reported by Kohler et al. [ Phys. Rev. Lett. 105(20), 203902 (2010)].We propose a two-color laser field scheme for controlling the quantum trajectories of ionizing electrons and for extending the CC harmonic energy. As a result, a high energy platform occurs in the HHG spectrum, which entirely originates from the CC harmonics, with a cutoff adjustable by the relative phase of the two-color fields. This provides further understanding of the dynamic feature of atoms and molecules in super intense laser fields and provides an opportunity to image the atomic or molecular potential.

  15. Theoretical study of terahertz generation from atoms and aligned molecules driven by two-color laser fields

    NASA Astrophysics Data System (ADS)

    Chen, Wenbo; Huang, Yindong; Meng, Chao; Liu, Jinlei; Zhou, Zhaoyan; Zhang, Dongwen; Yuan, Jianmin; Zhao, Zengxiu

    2015-09-01

    We study the generation of terahertz radiation from atoms and molecules driven by an ultrashort fundamental laser and its second-harmonic field by solving the time-dependent Schrödinger equation (TDSE). The comparisons between one-, two-, and three-dimensional TDSE numerical simulations show that the initial ionized wave packet and its subsequent acceleration in the laser field and rescattering with long-range Coulomb potential play key roles. We also present the dependence of the optimum phase delay and yield of terahertz radiation on the laser intensity, wavelength, duration, and ratio of two-color laser components. Terahertz wave generation from model hydrogen molecules is further investigated by comparing with high harmonic emission. It is found that the terahertz yield follows the alignment dependence of the ionization rate, while the optimal two-color phase delays vary by a small amount when the alignment angle changes from 0 to 90 degrees, which reflects the alignment dependence of attosecond electron dynamics. Finally, we show that terahertz emission might be used to clarify the origin of interference in high harmonic generation from aligned molecules by coincidentally measuring the alignment-dependent THz yields.

  16. Terahertz radiation driven by two-color laser pulses at near-relativistic intensities: Competition between photoionization and wakefield effects

    NASA Astrophysics Data System (ADS)

    González de Alaiza Martínez, P.; Davoine, X.; Debayle, A.; Gremillet, L.; Bergé, L.

    2016-06-01

    We numerically investigate terahertz (THz) pulse generation by linearly-polarized, two-color femtosecond laser pulses in highly-ionized argon. Major processes consist of tunneling photoionization and ponderomotive forces associated with transverse and longitudinal field excitations. By means of two-dimensional particle-in-cell (PIC) simulations, we reveal the importance of photocurrent mechanisms besides transverse and longitudinal plasma waves for laser intensities >1015 W/cm2. We demonstrate the following. (i) With two-color pulses, photoionization prevails in the generation of GV/m THz fields up to 1017 W/cm2 laser intensities and suddenly loses efficiency near the relativistic threshold, as the outermost electron shell of ionized Ar atoms has been fully depleted. (ii) PIC results can be explained by a one-dimensional Maxwell-fluid model and its semi-analytical solutions, offering the first unified description of the main THz sources created in plasmas. (iii) The THz power emitted outside the plasma channel mostly originates from the transverse currents.

  17. Formation of 85Rb2 ultracold molecules via photoassociation by two-color laser fields modulating the Gaussian amplitude

    NASA Astrophysics Data System (ADS)

    Huang, Yin; Zhang, Wei; Wang, Gao-Ren; Xie, Ting; Cong, Shu-Lin

    2012-10-01

    The formations of 85Rb2 molecules via photoassociation (PA) steered by two-color laser fields are explored theoretically in order to find an efficient and robust PA scheme. The PA processes steered by the PA pulses modulated by two Gaussian pulses and by two chirped pulses are discussed and compared in detail. The two pulses are coherent in the picosecond range and reach their maxima at the same time. The influences of the linear chirp rate, the frequency difference between two pulses, and the phase shift of the modulated envelope with respect to the maximum of the Gaussian envelope on the PA process are investigated. The yield of photoassociated molecules on vibrational levels with a binding energy of >1.0 cm-1 with respect to the 5S+5P1/2 dissociation limit can apparently be enhanced by choosing proper pulse parameters. Especially, the two-color laser field modulated by two chirped pulses can raise the PA efficiency on one side, and weaken the dependence of the PA process on phase shift on the other side.

  18. Terahertz radiation driven by two-color laser pulses at near-relativistic intensities: Competition between photoionization and wakefield effects

    PubMed Central

    González de Alaiza Martínez, P.; Davoine, X.; Debayle, A.; Gremillet, L.; Bergé, L.

    2016-01-01

    We numerically investigate terahertz (THz) pulse generation by linearly-polarized, two-color femtosecond laser pulses in highly-ionized argon. Major processes consist of tunneling photoionization and ponderomotive forces associated with transverse and longitudinal field excitations. By means of two-dimensional particle-in-cell (PIC) simulations, we reveal the importance of photocurrent mechanisms besides transverse and longitudinal plasma waves for laser intensities >1015 W/cm2. We demonstrate the following. (i) With two-color pulses, photoionization prevails in the generation of GV/m THz fields up to 1017 W/cm2 laser intensities and suddenly loses efficiency near the relativistic threshold, as the outermost electron shell of ionized Ar atoms has been fully depleted. (ii) PIC results can be explained by a one-dimensional Maxwell-fluid model and its semi-analytical solutions, offering the first unified description of the main THz sources created in plasmas. (iii) The THz power emitted outside the plasma channel mostly originates from the transverse currents. PMID:27255689

  19. Multistabilities and symmetry-broken one-color and two-color states in closely coupled single-mode lasers

    NASA Astrophysics Data System (ADS)

    Clerkin, Eoin; O'Brien, Stephen; Amann, Andreas

    2014-03-01

    We theoretically investigate the dynamics of two mutually coupled, identical single-mode semi-conductor lasers. For small separation and large coupling between the lasers, symmetry-broken one-color states are shown to be stable. In this case the light outputs of the lasers have significantly different intensities while at the same time the lasers are locked to a single common frequency. For intermediate coupling we observe stable symmetry-broken two-color states, where both lasers lase simultaneously at two optical frequencies which are separated by up to 150 GHz. Using a five-dimensional model, we identify the bifurcation structure which is responsible for the appearance of symmetric and symmetry-broken one-color and two-color states. Several of these states give rise to multistabilities and therefore allow for the design of all-optical memory elements on the basis of two coupled single-mode lasers. The switching performance of selected designs of optical memory elements is studied numerically.

  20. Terahertz radiation driven by two-color laser pulses at near-relativistic intensities: Competition between photoionization and wakefield effects.

    PubMed

    González de Alaiza Martínez, P; Davoine, X; Debayle, A; Gremillet, L; Bergé, L

    2016-01-01

    We numerically investigate terahertz (THz) pulse generation by linearly-polarized, two-color femtosecond laser pulses in highly-ionized argon. Major processes consist of tunneling photoionization and ponderomotive forces associated with transverse and longitudinal field excitations. By means of two-dimensional particle-in-cell (PIC) simulations, we reveal the importance of photocurrent mechanisms besides transverse and longitudinal plasma waves for laser intensities >10(15) W/cm(2). We demonstrate the following. (i) With two-color pulses, photoionization prevails in the generation of GV/m THz fields up to 10(17) W/cm(2) laser intensities and suddenly loses efficiency near the relativistic threshold, as the outermost electron shell of ionized Ar atoms has been fully depleted. (ii) PIC results can be explained by a one-dimensional Maxwell-fluid model and its semi-analytical solutions, offering the first unified description of the main THz sources created in plasmas. (iii) The THz power emitted outside the plasma channel mostly originates from the transverse currents. PMID:27255689

  1. High-order harmonic generation of N2 molecule in two-color circularly polarized laser fields

    NASA Astrophysics Data System (ADS)

    Hui, Du; Jun, Zhang; Shuai, Ben; Hui-Ying, Zhong; Tong-Tong, Xu; Jing, Guo; Xue-Shen, Liu

    2016-04-01

    The generation of high-order harmonics and the attosecond pulse of the N2 molecule in two-color circularly polarized laser fields are investigated by the strong-field Lewenstein model. We show that the plateau of spectra is dramatically extended and a continuous harmonic spectrum with the bandwidth of 113 eV is obtained. When a static field is added to the x direction, the quantum path control is realized and a supercontinuum spectrum can be obtained, which is beneficial to obtain a shorter attosecond pulse. The underlying physical mechanism is well explained by the time–frequency analysis and the semi-classical three-step model with a finite initial transverse velocity. By superposing several orders of harmonics in the combination of two-color circularly polarized laser fields and a static field, an isolated attosecond pulse with a duration of 30 as can be generated. Project supported by the National Natural Science Foundation of China (Grant Nos. 61575077, 11271158, and 11574117).

  2. Fabrication of two-color surface emitting device of a coupled vertical cavity structure with InAs quantum dots formed by wafer bonding

    NASA Astrophysics Data System (ADS)

    Ota, Hiroto; Lu, Xiangmeng; Kumagai, Naoto; Kitada, Takahiro; Isu, Toshiro

    2016-04-01

    We fabricated a two-color surface emitting device of a coupled cavity structure, which is applicable to terahertz light source. GaAs/AlGaAs vertical multilayer cavity structures were grown on (001) and (113)B GaAs substrates and the coupled multilayer cavity structure was fabricated by wafer bonding them. The top cavity contains self-assembled InAs quantum dots (QDs) as optical gain materials for two-color emission of cavity-mode lights. The bonding position was optimized for the equivalent intensity of two-color emission. We formed a current injection structure, and two-color emission was observed by current injection, although no lasing was observed.

  3. A Two-Color Fourier Transform Mm-Wave Spectrometer for Gas Analysis Operating from 260-295 GHZ

    NASA Astrophysics Data System (ADS)

    Steber, Amanda L.; Harris, Brent J.; Lehmann, Kevin K.; Pate, Brooks H.

    2013-06-01

    We have designed a two-color mm-wave spectrometer for Fourier transform mm-wave spectroscopy that uses consumer level components for the tunable synthesizers, digital control of the pulse modulators, and digitization of the coherent free induction decay (FID). The excitation pulses are generated using an x24 active multiplier chain (AMC) that produces a peak power of 30 mW. The microwave input to the AMC is generated in a frequency up conversion circuit that accepts a microwave input frequency from about 2-4 GHz. This circuit also generates the input to the mm-wave subhamonic mixer that creates the local oscillator from a separate 2-4 GHz microwave input. Excitation pulses at two independently tunable frequencies are generated using a dual-channel source based on a low-cost, wideband synthesizer integrated circuit (Valon Technology Model 5008). The outputs of the synthesizer are pulse modulated using a PIN diode switch that is driven using the arbitrary waveform generator (AWG) output of a USB-controlled high-speed digitizer / arbitrary waveform generator combination unit (Tie Pie HS-5 530 XM). The two pulses are combined using a Wilkinson power divider before input to the up conversion circuit. The FID frequency is down converted in a two-stage mixing process to 65 MHz. The two LO frequencies used in the receiver are provided by a second Valon 5008. The FID is digitized at 200 MSamples/s using the 12-bit Tie Pie digitizer. The digital oscilloscope (and its AWG channel) and the two synthesizers use a 10 MHz reference signal from a Rubidium clock to permit time-domain signal averaging. A key feature of the digital oscilloscope is its deep memory of 32 Mpts (complemented by the 64 Mpt memory in the 240 MS/s AWG). This makes it possible to perform several one- and two-color coherent measurements, including pulse echoes and double-resonance spectroscopy, in a single "readout" experiment to speed the analysis of mm-wave rotational spectra. The spectrometer sensitivity

  4. Two color multichannel heterodyne interferometer set up for high spatial resolution electron density profile measurements in TJ-II

    SciTech Connect

    Pedreira, P.; Criado, A. R.; Acedo, P.; Esteban, L.; Sanchez, M.; Sanchez, J.

    2010-10-15

    A high spatial resolution two color [CO{sub 2}, {lambda}=10.6 {mu}m/Nd:YAG (Nd:YAG denotes neodymium-doped yttrium aluminum garnet), and {lambda}=1.064 {mu}m] expanded-beam multichannel heterodyne interferometer has been installed on the TJ-II stellarator. Careful design of the optical system has allowed complete control on the evolution of both Gaussian beams along the interferometer, as well as the evaluation and optimization of the spatial resolution to be expected in the measurements. Five CO{sub 2} (measurement) channels and three Nd:YAG (vibration compensation) channels have been used to illuminate the plasma with a probe beam of 100 mm size. An optimum interpolation method has been applied to recover both interferometric phasefronts prior to mechanical vibration subtraction. The first results of the installed diagnostic are presented in this paper.

  5. Two-color light-emitting diodes with polarization-sensitive high extraction efficiency based on graphene

    NASA Astrophysics Data System (ADS)

    H, Sattarian; S, Shojaei; E, Darabi

    2016-05-01

    In the present study, graphene photonic crystals are employed to enhance the light extraction efficiency (LEE) of two-color, red and blue, light-emitting diode (LED). The transmission characteristics of one-dimensional (1D) Fibonacci graphene photonic crystal LED (FGPC-LED) are investigated by using the transfer matrix method and the scaling study is presented. We analyzed the influence of period, thickness, and permittivity in the structure to enhance the LEE. The transmission spectrum of 1D FGPC has been optimized in detail. In addition, the effects of the angle of incidence and the state of polarization are investigated. As the main result, we found the optimum values of relevant parameters to enhance the extraction of red and blue light from an LED as well as provide perfect omnidirectional and high peak transmission filters for the TE and TM modes.

  6. Selection rule and efficiency for autoionization of diazabicyclooctane as studied by two-color double-resonance spectroscopy

    SciTech Connect

    Fujii, M.; Sato, K.; Kimura, K.

    1987-12-17

    Photoelectron spectra due to autoionization for two series of high Rydberg states have been observed for diazabicyclooctane (DABCO) in a supersonic jet. The selection rule of the autoionization has been found to be ..delta..v = -1 for each vibrational mode involved in the Rydberg states, consistent with Berry's theory available for the vibrational autoionization of a polyatomic molecule. The relative autoionization efficiencies Phi/sub a/ for the high Rydberg series have also been determined from two-color MPI and fluorescence dip spectra. The irregular variation of Phi/sub a/ with the principal quantum number n has been found for the two Rydberg series, suggesting the irregular variation in their nonradiative rates

  7. Influences of different gases on the terahertz radiation based on the application of two-color laser pulses

    SciTech Connect

    Moradi, S.; Ganjovi, A.; Shojaei, F.; Saeed, M.

    2015-10-15

    In this work, using a two-dimensional Particle In Cell-Monte Carlo Collision simulation method, a comparative study is performed on the influences of different types of atomic and molecular gases at various background gas pressures on the generation of broadband and intense Terahertz (THz) radiation via the application of two-color laser pulses. These two modes are focused into Argon (Ar), Xenon (Xe), Nitrogen (N{sub 2}), Oxygen (O{sub 2}), and air as the background gaseous media and the plasma channel is created. It is observed that the THz radiation emission dramatically changes due to the propagation effects. A wider THz pulse is emitted from the formed plasma channel at the higher gas pressures. The significant effects of the propagation features of the emitted THz pulse on its energy at the longer lengths of the plasma channel are observed.

  8. Two-color interference effect involving three-photon atomic excitation and four-wave mixing in crossed laser beams

    SciTech Connect

    Peet, V.

    2007-09-15

    Through multiphoton ionization measurements, the polarization effects in destructive quantum interference under three-photon resonant excitation have been studied. Recent observations [V. Peet, Phys. Rev. A 74, 033406 (2006)] have indicated that contrary to the well-known pattern of a total suppression of resonance excitation, the destructive interference becomes incomplete if three-photon transition is driven by crossed beams with orthogonal polarization planes. These observations have been tested for a more general case of two-color excitation and very similar polarization-dependent anomalies in the interference character have been registered. It has been shown that the destructive interference is modified and the resonance excitation does occur if two crossed laser beams have opposite circular polarizations. The pressure-induced evolution of the uncanceled ionization peaks has the ratio of blue shift to width close to 0.5 exactly as it is known for resonance ionization peaks registered under excitation by counterpropagating laser beams.

  9. Ionization-Induced Multiwave Mixing: Terahertz Generation with Two-Color Laser Pulses of Various Frequency Ratios

    NASA Astrophysics Data System (ADS)

    Kostin, V. A.; Laryushin, I. D.; Silaev, A. A.; Vvedenskii, N. V.

    2016-07-01

    Ultrafast strong-field ionization is shown to be accompanied by atypical multiwave mixing with the number of mixed waves defined by the dependence of the ionization rate on the field strength. For two-color laser pulses of various frequency ratios, this results in the excitation of a free-electron current at laser combination frequencies and possibly in the excitation of the zero-frequency (residual) current responsible for terahertz (THz) generation in a formed plasma. The high-order nature of ionization-induced wave mixing may cause THz generation with uncommon laser frequency ratios (such as 2 : 3 and 3 : 4 ) to be virtually as effective as that with the commonly used frequency ratio of 1 : 2 .

  10. Analysis of two-color geodimeter measurements of deformation within the Long Valley caldera: June 1983 to October 1985.

    USGS Publications Warehouse

    Langbein, J.; Linker, M.; Tupper, D.

    1987-01-01

    Line length changes from several baselines in a trilateration network within the Long Valley caldera clearly define a decrease in strain rate from June 1983 through October 1985. The data consist of more than 1600 length measurements on 23 baselines using a two- color geodimeter, which has a precision of 0.2 ppm of the line length. A model is constructed using these observations as well as yearly observations of a trilateration network within and near the caldera. The model contains two points of inflation located at 5 and 10 km beneath the resurgent dome of the caldera plus dextral slip on a fault plane within the south moat within an elastic half-space. -from Authors

  11. Probing the influence of the Coulomb field on atomic ionization by sculpted two-color laser fields

    NASA Astrophysics Data System (ADS)

    Xie, Xinhua; Roither, Stefan; Gräfe, Stefanie; Kartashov, Daniil; Persson, Emil; Lemell, Christoph; Zhang, Li; Schöffler, Markus S.; Baltuška, Andrius; Burgdörfer, Joachim; Kitzler, Markus

    2013-04-01

    Interpretation of electron or photon spectra obtained with strong laser pulses that may carry attosecond dynamical and Ångström structural information about atoms or molecules usually relies on variants of the strong-field approximation (SFA) within which the influence of the Coulomb potential on the electron trajectory is neglected. We employ two-color sculpted laser fields to experimentally tune and probe the influence of the Coulomb field on the strong-field-driven wavepacket as observed by two-dimensional electron and ion momentum spectra. By comparison of measured spectra with predictions of the three-dimensional time-dependent Schrödinger equation as well as the quasi-classical limit of the SFA, the strong-field classical trajectory model, we are able to trace back the influence of the Coulomb field to the timing of the wavepacket release with sub-cycle precision.

  12. Interaction of toluene with two-color asymmetric laser fields: Controlling the directional emission of molecular hydrogen fragments

    NASA Astrophysics Data System (ADS)

    Kaziannis, S.; Kotsina, N.; Kosmidis, C.

    2014-09-01

    The interaction of toluene with strong asymmetric two-color laser irradiation of 40 fs duration is studied by means of Time of flight mass spectrometry. Highly energetic H2+ and H3+ fragment ions are produced through an isomerization process taking place within transient multiply charged parent ions. Comparative study of deuterium labeled toluene isotopes enables the discrimination between molecular hydrogen fragments formed exclusively within the CH3- part from those that require hydrogen atom exchange between the former and the phenyl moiety. It is demonstrated that by manipulating the relative phase of the ω/2ω field components the selective ionization of oriented toluene molecules can be used as a tool to control the directional emission of the H2+, H3+ species.

  13. Interaction of toluene with two-color asymmetric laser fields: controlling the directional emission of molecular hydrogen fragments.

    PubMed

    Kaziannis, S; Kotsina, N; Kosmidis, C

    2014-09-14

    The interaction of toluene with strong asymmetric two-color laser irradiation of 40 fs duration is studied by means of Time of flight mass spectrometry. Highly energetic H2(+) and H3(+) fragment ions are produced through an isomerization process taking place within transient multiply charged parent ions. Comparative study of deuterium labeled toluene isotopes enables the discrimination between molecular hydrogen fragments formed exclusively within the CH3- part from those that require hydrogen atom exchange between the former and the phenyl moiety. It is demonstrated that by manipulating the relative phase of the ω/2ω field components the selective ionization of oriented toluene molecules can be used as a tool to control the directional emission of the H2(+), H3(+) species. PMID:25217928

  14. Single-pinhole diffraction of few-cycle isolated attosecond pulses with a two-color field

    NASA Astrophysics Data System (ADS)

    Shaoyi, Wang; Dan, Han; Kegong, Dong; Yuchi, Wu; Fang, Tan; Bin, Zhu; Quanping, Fan; Leifeng, Cao; Yuqiu, Gu

    2016-03-01

    The spatio-temporal characterization of an isolated attosecond pulse is investigated theoretically in a two-color field. Our results show that a few-cycle isolated attosecond pulse with the center wavelength of 16 nm can be generated effectively by adding a weak controlling field. Using the split and delay units, the isolated attosecond pulse can be split to the two same ones, and then single-pinhole diffractive patterns of the two pulses with different delays can be achieved. The diffractive patterns depend severely on the periods of the attosecond pulses, which can be helpful to obtain temporal information of the coherent sources. Project supported by the National Science Instruments Major Project of China (Grant No. 2012YQ130125), the National Natural Science Foundation of China (Grant Nos. 11405159, 11375161, and 11174259), and the Science and Technology on Plasma Physics Laboratory at CAEP (Grant No. 9140C680302130C68242).

  15. Systematic studies of two-color pump-induced high-order harmonic generation in plasma plumes

    SciTech Connect

    Ganeev, R. A.; Singhal, H.; Naik, P. A.; Chakera, J. A.; Vora, H. S.; Khan, R. A.; Gupta, P. D.

    2010-11-15

    High-order harmonic generation (HHG) has been studied in various laser-produced plasma plumes using a two-color orthogonally polarized beam with a 12:1 energy ratio between the fundamental and second-harmonic (SH) components. The influence of the relative phase between the fundamental and SH waves on the HHG efficiency has been investigated. Odd and even harmonic generation in plasma plumes containing nanoparticles, fullerenes, carbon nanotubes, and other samples was optimized. The effect of the variation in the SH intensity on the HHG conversion efficiency in carbon aerogel and silver plasma plumes has also been studied. It is shown that by increasing the SH intensity, one can generate only even harmonics by suppressing the odd harmonics.

  16. Interaction of toluene with two-color asymmetric laser fields: Controlling the directional emission of molecular hydrogen fragments

    SciTech Connect

    Kaziannis, S.; Kotsina, N.; Kosmidis, C.

    2014-09-14

    The interaction of toluene with strong asymmetric two-color laser irradiation of 40 fs duration is studied by means of Time of flight mass spectrometry. Highly energetic H{sub 2}{sup +} and H{sub 3}{sup +} fragment ions are produced through an isomerization process taking place within transient multiply charged parent ions. Comparative study of deuterium labeled toluene isotopes enables the discrimination between molecular hydrogen fragments formed exclusively within the CH{sub 3}- part from those that require hydrogen atom exchange between the former and the phenyl moiety. It is demonstrated that by manipulating the relative phase of the ω/2ω field components the selective ionization of oriented toluene molecules can be used as a tool to control the directional emission of the H{sub 2}{sup +}, H{sub 3}{sup +} species.

  17. Remote generation of high-energy terahertz pulses from two-color femtosecond laser filamentation in air

    SciTech Connect

    Wang, T.-J.; Daigle, J.-F.; Yuan, S.; Chin, S. L.; Theberge, F.; Chateauneuf, M.; Dubois, J.; Roy, G.; Zeng, H.

    2011-05-15

    We experimentally investigated the dynamic behavior of remote terahertz (THz) generation from two-color femtosecond laser-induced filamentation in air. A record-high THz pulse energy of 570 nJ at frequency below 5.5 THz was measured by optimizing the pump parameters at a controllable remote distance of 16 m, while super-broadband THz (<300 THz) pulse energy was up to 2.8 {mu}J. A further energy-scaling possibility was proposed. By analyzing simultaneously the fluorescence from both neutral N{sub 2} and N{sub 2}{sup +} in the filament, we found that the enhancement of THz radiation was due principally to guiding of the weak second-harmonic pulse inside the filament of the first strong fundamental pulse.

  18. Demonstration of a two-color 320×256 quantum dots-in-a-well focal plane array

    NASA Astrophysics Data System (ADS)

    Varley, Eric S.; Ramirez, David A.; Brown, Jay S.; Lee, Sang Jun; Stintz, Andreas; Lenz, Michael; Krishna, Sanjay; Reisinger, Axel; Sundaram, Mani

    2007-09-01

    In our research group, we develop novel dots-in-a-well (DWELL) photodetectors that are a hybrid of the quantum dot infrared photodetector (QDIP). The DWELL detector consists of an active region composed of InAs quantum dots embedded in InGaAs quantum wells. By adjusting the InGaAs well thickness, our structure allows for the manipulation of the operating wavelength and the nature of the transitions (bound-to-bound, bound-to-quasibound and bound-to-continuum) of the detector. Based on these principles, DWELL samples were grown using molecular beam epitaxy and fabricated into 320 x 256 focal plane arrays (FPAs) with Indium bumps using standard lithography at the University of New Mexico. The FPA evaluated was hybridized to an Indigo 9705 readout integrated circuit (ROIC) in collaboration with QmagiQ LLC and tested with a CamIRa TM system manufactured by SE-IR Corp. From this evaluation, we report the first two-color, co-located quantum dot based imaging system that can be used to take multicolor images using a single FPA. We demonstrated that we can operate the device at an intermediate bias (V b=-1.25 V) and obtain two color response from the FPA at 77K. Using filter lenses, both MWIR and LWIR responses were obtained from the array at the same bias voltage. The MWIR and LWIR responses are thought to be from bound states in the dot to higher and lower lying states in the quantum well respectively. Temporal NEDT for the DWELL FPA was measured to be 80mK at 77K.

  19. Polar red-emitting rhodamine dyes with reactive groups: synthesis, photophysical properties, and two-color STED nanoscopy applications.

    PubMed

    Kolmakov, Kirill; Wurm, Christian A; Meineke, Dirk N H; Göttfert, Fabian; Boyarskiy, Vadim P; Belov, Vladimir N; Hell, Stefan W

    2014-01-01

    The synthesis, reactivity, and photophysical properties of new rhodamines with intense red fluorescence, two polar residues (hydroxyls, primary phosphates, or sulfonic acid groups), and improved hydrolytic stability of the amino-reactive sites (NHS esters or mixed N-succinimidyl carbonates) are reported. All fluorophores contain an N-alkyl-1,2-dihydro-2,2,4-trimethylquinoline fragment, and most of them bear a fully substituted tetrafluoro phenyl ring with a secondary carboxamide group. The absorption and emission maxima in water are in the range of 635-639 and 655-659 nm, respectively. A vastly simplified approach to red-emitting rhodamines with two phosphate groups that are compatible with diverse functional linkers was developed. As an example, a phosphorylated dye with an azide residue was prepared and was used in a click reaction with a strained alkyne bearing an N-hydroxysuccinimid (NHS) ester group. This method bypasses the undesired activation of phosphate groups, and gives an amphiphilic amino-reactive dye, the solubility and distribution of which between aqueous and organic phases can be controlled by varying the pH. The presence of two hydroxyl groups and a phenyl ring with two carboxyl residues in the dyes with another substitution pattern is sufficient for providing the hydrophilic properties. Selective formation of a mono-N-hydroxysuccinimidyl ester from 5-carboxy isomer of this rhodamine is reported. The fluorescence quantum yields varied from 58 to 92% for free fluorophores, and amounted to 18-64% for antibody conjugates in aqueous buffers. The brightness and photostability of these fluorophores facilitated two-color stimulated emission depletion (STED) fluorescence nanoscopy of biological samples with high contrast and minimal background. Selecting a pair of fluorophores with absorption/emission bands at 579/609 and 635/655 nm enabled two-color channels with low cross-talk and negligible background at approximately 40 nm resolution. PMID:24338798

  20. Table-top two-color soft X-ray laser by means of Ni-like plasmas

    NASA Astrophysics Data System (ADS)

    Masoudnia, Leili; Ruiz-Lopez, Mabel; Bleiner, Davide

    2016-04-01

    Laser-produced Ni-like plasmas are known as active media for extreme ultraviolet lasing, with the flexibility to two-color lasing. Two-color laser generation is very complex at accelerator facilities. In this work, plasma lasing at the 3d94d1(J = 0) → 3d94p1(J = 1) (collisional-pumping process) and the 3d94f1(J = 1) → 3d94d1(J = 1) (photo-pumping process) transitions is studied experimentally and computationally. Several key characteristics of collisional- and photo-pumping laser, such as divergence, pointing stability, and intensity have been investigated. The measurements showed different pulse characteristics for the two lasing processes affected by plasma inhomogeneity in temperature and density. Analytical expressions of these characteristics for both collisional- and photo-pumping are derived. It is found that the plasma that maximizes the photo-pumping lasing is 20% hotter and 70% denser than the plasma that optimizes the collisional-pumping lasing. The gain of collisional pumping is ≈4 times higher than the gain for the photo-pumping. The gain lifetime is a factor of ≈5.2 larger for the monopole-pumping. Similarly, the gain thickness is a factor of ≈1.8 larger. It is also found that the gain build-up time for collisional- and photo-pumping is 0.7 ps and 0.9 ps, respectively, whereas the build-up length-scale is 11.5 μm and 6.3 μm, respectively.

  1. Ionization states of heavy elements observed in the 1974 May 14-15 anomalous solar particle event

    NASA Technical Reports Server (NTRS)

    Ma Sung, L. S.; Gloeckler, G.; Fan, C. Y.; Hovestadt, D.

    1981-01-01

    The charge states of heavy ions accelerated in the (3)He-Fe rich solar particle event of 1974 May 14-15 are determined using data from the Interplanetary Monitoring Platform-8. In addition to Fe(+11,12) both 0(+5) and Fe(+16,17,18) are also present suggesting variations in coronal temperatures over a range from approximately 400,000 to 5,000,000 K. The presence of 0(+5) and Fe(+16-18) may be explained by a resonant plasma heating mechanism proposed to account for the enhancements of (3)He and Fe.

  2. Molecular characterization of the t(4;12)(q27~28;q14~15) chromosomal rearrangement in lipoma

    PubMed Central

    Agostini, Antonio; Gorunova, Ludmila; Bjerkehagen, Bodil; Lobmaier, Ingvild; Heim, Sverre; Panagopoulos, Ioannis

    2016-01-01

    Lipomas are common benign soft tissue tumors whose genetic and cytogenetic features are well characterized. The karyotype is usually near- or pseudodiploid with characteristic structural chromosomal aberrations. The most common rearrangements target the high mobility group AT-hook 2 (HMGA2) gene in 12q14.3, with breakpoints occurring within or outside of the gene locus leading to deregulation of HMGA2. The most common fusion partner for HMGA2 in lipoma is lipoma-preferred partner (3q27), but also other genes frequently recombine with HMGA2. Furthermore, truncated HMGA2 transcripts are recurrently observed in lipomas. The present study describes 5 lipomas carrying the translocation t(4;12)(q27~28;q14~15) as the sole chromosomal anomaly, as well as 1 lipoma in which the three-way translocation t(1;4;12)(q21;q27~28;q14~15) was identified. Molecular analyses performed on 4 of these cases detected 4 truncated forms of HMGA2. In 3 tumors, the HMGA2 truncated transcripts included sequences originating from the chromosomal sub-band 4q28.1. Notably, in 2 of these cases, the fourth exon of HMGA2 was fused to transposable elements located in 4q28.1. PMID:27588119

  3. Modeling cloth at micron resolution

    NASA Astrophysics Data System (ADS)

    Bala, Kavita

    2014-02-01

    Fabric is one of the most common materials in our everyday lives, and accurately simulating the appearance of cloth is a critical problem in graphics, design, and virtual prototyping. But modeling and rendering fabric is very challenging because fabrics have a very complex structure, and this structure plays an important role in their visual appearance—cloth is made of fibers that are twisted into yarns which are woven into patterns. Light interacting with this complex structure produce the characteristic visual appearance that humans recognize as silk, cotton, or wool. In this paper we present an end-to-end pipeline to model and render fabrics: we introduce a novel modality to create volume models of fabric at micron resolution using CT technology coupled with photographs; a new technique to synthesize models of user-specified designs from such CT scans; and finally, an efficient algorithm to render these complex volumetric models for practical applications. This pipeline produces the most realistic images of virtual cloth to date, and opens the way to bridging the gap between real and virtual fabric appearance.

  4. Theoretical investigation of a novel high density cage compound 4,8,11,14,15-pentanitro-2,6,9,13-tetraoxa-4,8,11,14,15-pentaazaheptacyclo[5.5.1.1(3,11).1(5,9)] pentadecane.

    PubMed

    Lin, He; Zhu, Shun-guan; Zhang, Lin; Peng, Xin-hua; Chen, Peng-yuan; Li, Hong-zhen

    2013-03-01

    A novel polynitro cage compound 4,8,11,14,15-pentanitro-2,6,9,13-tetraoxa-4,8,11,14,15-pentaazaheptacyclo [5.5.1.1(3,11).1(5,9)]pentadecane(PNTOPAHP) has been designed and investigated at the DFT-B3LYP/6-31(d) level. Properties, such as electronic structure, IR spectrum, heat of formation, thermodynamic properties and crystal structure have been predicted. This compound is most likely to crystallize in C2/c space group, and the corresponding cell parameters are Z = 8, a = 29.78 Å, b = 6.42 Å, c = 32.69 Å, α = 90.00°, β = 151.05°, γ = 90.00° and ρ = 1.94 g/cm(3). In addition, the detonation velocity and pressure have also been calculated by the empirical Kamlet-Jacobs equation. As a result, the detonation velocity and pressure of this compound are 9.82 km/s, 44.67 GPa, respectively, a little higher than those of 4,10-dinitro-2,6,8,12-tetraoxa-4,10-diazaisowurtzitane(TEX, 9.28 km/s, 40.72 GPa). This compound has a comparable chemical stability to TEX, based on the N-NO(2) trigger bond length analysis. The bond dissociation energy ranges from 153.09 kJ mol(-1) to 186.04 kJ mol(-1), which indicates that this compound meets the thermal stability requirement as an exploitable HEDM. PMID:23111684

  5. High Energy 2-Micron Laser Developments

    NASA Technical Reports Server (NTRS)

    Yu, Jirong; Trieu, Bo C.; Petros, Mulugeta; Bai, Yingxin; Petzar, Paul J.; Koch, Grady J.; Singh, Upendra N.; Kavaya, Michael J.

    2007-01-01

    A master oscillator power amplifier, high energy Q-switched 2-micron laser system has been recently demonstrated. The laser and amplifiers are all designed in side-pumped rod configuration, pumped by back-cooled conductive packaged GaAlAs diode laser arrays. This 2-micron laser system provides nearly transform limited beam quality.

  6. One Micron Laser Technology Advancements at GSFC

    NASA Technical Reports Server (NTRS)

    Heaps, William S.

    2010-01-01

    This slide presentation reviews the advancements made in one micron laser technology at Goddard Space Flight Center. It includes information about risk factors that are being addressed by GSFC, and overviews of the various programs that GSFC is currently managing that are using 1 micron laser technology.

  7. Generation of two-color ultra-short radiation pulses from two electron bunches and a chirped seeded free-electron laser

    NASA Astrophysics Data System (ADS)

    Feng, Chao; Wang, Zhen; Wang, Xingtao; Huang, Dazhang

    2016-01-01

    In this paper we describe a new method for the realization of two-color femtosecond radiation pulses in a seeded free-electron laser (FEL). The two-color pulses are obtained from two electron bunches and a chirped seeding laser. Compared to the previous methods based on seeded FELs, our method has the advantages of producing two-color FEL pulses with more flexible tunability both in the pulse durations and separations. Numerical simulations for the Dalian Coherent Light Source confirm that femtosecond XUV pulses with variable pulse durations and time delay can be directly generated from a chirped seed laser at 250 nm by using this technique. We also show the possibility of performing a proof-of-principle experiment of this technique based on the Shanghai Deep-Ultraviolet FEL facility.

  8. Thermoreversible Changes in Aligned and Cross-Linked Block Copolymer Melts Studied by Two Color Depolarized Light Scattering

    SciTech Connect

    Wilbur, Jeffrey D.; Gomez, Enrique D.; Ellsworth, Mark W.; Garetz, Bruce A.; Balsara, Nitash P.

    2012-09-04

    A procedure for creating samples that can be repeatedly cycled between weakly aligned and strongly aligned states is described. Poly(styrene-b-isoprene) block copolymer samples were first shear-aligned and then cross-linked using a high energy electron beam. Samples with more than 1.0 cross-links per chain on average showed almost complete recovery of their initial alignment state even after 20 cycles of heating above the order–disorder transition temperature of the un-cross-linked block copolymer. Samples with 1.1 cross-links per chain, which showed over 90% loss of alignment on heating and almost 100% recovery of alignment on cooling, provided the best example of a reversible aligned-to-unaligned transition. Samples with lower cross-linking densities exhibited irreversible loss of alignment upon heating, while those with higher cross-linking densities exhibited less than 90% loss of alignment upon heating. Alignment was quantified by a technique that we call two color depolarized light scattering (TCDLS), an extension of the traditional depolarized light scattering experiment used to determine the state of order in block copolymers. Qualitative confirmation of our interpretation of TCDLS data was obtained by small-angle X-ray scattering and transmission electron microscopy.

  9. Parametric study of broadband terahertz radiation generation based on interaction of two-color ultra-short laser pulses

    SciTech Connect

    Moradi, S.; Ganjovi, A.; Shojaei, F.; Saeed, M.

    2015-04-15

    In this work, using a two-dimensional kinetic model based on particle in cell-Monte Carlo collision simulation method, the influence of different parameters on the broadband intense Terahertz (THz) radiation generation via application of two-color laser fields, i.e., the fundamental and second harmonic modes, is studied. These two modes are focused into the molecular oxygen (O{sub 2}) with uniform density background gaseous media and the plasma channels are created. Thus, a broadband THz pulse that is around the plasma frequency is emitted from the formed plasma channel and co-propagates with the laser pulse. For different laser pulse shapes, the THz electric field and its spectrum are both calculated. The effects of laser pulse and medium parameters, i.e., positive and negative chirp pulse, number of laser cycles in the pulse, laser pulse shape, background gas pressure, and exerted DC electric field on THz spectrum are verified. Application of a negatively chirped femtosecond (40 fs) laser pulse results in four times enhancement of the THz pulse energy (2 times in THz electric field). The emission of THz radiation is mostly observed in the forward direction.

  10. Tunable Two-color Luminescence and Host-guest Energy Transfer of Fluorescent Chromophores Encapsulated in Metal-Organic Frameworks

    NASA Astrophysics Data System (ADS)

    Yan, Dongpeng; Tang, Yanqun; Lin, Heyang; Wang, Dan

    2014-03-01

    Co-assembly of chromophore guests with host matrices can afford materials which have photofunctionalities different from those of individual components. Compared with clay and zeolite materials, the use of metal-organic frameworks (MOFs) as a host structure for fabricating luminescent host-guest materials is still at an early stage. Herein, we report the incorporation of a laser dye, 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM), into stilbene-based and naphthalene-based MOF systems. The resulting materials exhibit blue/red two-color emission, and the intensity ratio of blue to red fluorescence varies in different planes within the MOF crystal as detected by 3D confocal fluorescence microscopy. The observed changes in ratiometric fluorescence suggest the occurrence of energy transfer from MOF host to DCM molecules, which can be further confirmed by periodic density functional theoretical (DFT) calculations. Moreover, selective changes in luminescence behavior are observed on treating the guest@MOF samples with volatile organic compounds (methanol, acetone and toluene), indicating that these host-guest systems have potential applications as fluorescence sensors. It can be expected that by rational selection of MOF hosts and guest chromophores with suitable emissive colors and energy levels, a wide variety of multi-color luminescent and energy-transfer systems can readily be prepared in a similar manner.

  11. Two-color infrared predissociation spectroscopy of C₆H₆²⁺ isomers using helium tagging.

    PubMed

    Jašík, Juraj; Gerlich, Dieter; Roithová, Jana

    2015-03-19

    Two-color IR-IR isomer selective predissociation spectra of helium-tagged C6H6(2+) are presented. The dications are generated via electron bombardment of either benzene or 1,3-cyclohexadiene. After mass selection they are injected into a 2.6 K cold ion trap where the presence of a dense He buffer gas not only cools them but also leads to He attachment. The ion ensemble is exposed to one or two intense IR pulses from optical parametric oscillators (OPOs) (1200-3100 cm(-1)) before it is extracted, mass analyzed, and detected. On the basis of a comparison with theoretical predictions, the resulting spectral features allow us to separate and assign different isomers of C6H6(2+) dications. Compression of the ion cloud very close to the axis of the linear quadrupole trap and coaxial superposition of well-collimated laser beams results in the fragmentation of almost all helium complexes at specific wavelengths. This unique feature enables us to record fluence-dependent attenuation curves for individual absorption bands and thus determine not only absorption cross sections but also the composition of the ion mixture. PMID:25402726

  12. Route to optimal generation of soft X-ray high harmonics with synthesized two-color laser pulses

    PubMed Central

    Jin, Cheng; Wang, Guoli; Le, Anh-Thu; Lin, C. D.

    2014-01-01

    High harmonics extending to X-rays have been generated from gases by intense lasers. To establish these coherent broadband radiations as an all-purpose tabletop light source for general applications in science and technology, new methods are needed to overcome the present low conversion efficiencies. Here we show that the conversion efficiency may be drastically increased with an optimized two-color pulse. By employing an optimally synthesized 2-µm mid-infrared laser and a small amount of its third harmonic, we show that harmonic yields from sub- to few-keV energy can be increased typically by ten-fold over the optimized single-color one. By combining with favorable phase-matching and together with the emerging high-repetition MHz mid-infrared lasers, we anticipate efficiency of harmonic yields can be increased by four to five orders in the near future, thus paving the way for employing high harmonics as useful broadband tabletop light sources from the extreme ultraviolet to the X-rays, as well as providing new tools for interrogating ultrafast dynamics of matter at attosecond timescales. PMID:25400015

  13. Discrimination of glycoproteins via two-color laser-induced fluorescence detection coupled with postcolumn derivatization in capillary electrophoresis.

    PubMed

    Tabara, Ayumi; Kaneta, Takashi

    2013-08-01

    Here, we report a novel method consisting of capillary electrophoretic separation followed by two-color LIF detection with postcolumn derivatization. The method can be used to discriminate glycoproteins in a protein mixture containing both glycosylated and unglycosylated proteins. The detector permitted simultaneous measurements of two electropherograms obtained by 450 nm (diode laser) and 532 nm (Nd:YAG laser) lasers excited native proteins following postcolumn derivatization with naphthalene-2,3-dicarboxaldehyde and concanavalin A (Con A) labeled with tetramethylrhodamine (rhodamine-labeled Con A), respectively. So, a protein can be assigned as glycosylated if it shows a peak at the same migration time in both electropherograms. According to the proposed principle, in a single run we discriminated a glycosylated protein (thyroglobulin) from an unglycosylated protein (albumin) in the presence of rhodamine-labeled Con A. Because the methodology permits the simultaneous detection of native proteins and their complexes with a fluorescently labeled probe, it should have broad applicability to binding assays. PMID:23775479

  14. Tunable Two-color Luminescence and Host–guest Energy Transfer of Fluorescent Chromophores Encapsulated in Metal-Organic Frameworks

    PubMed Central

    Yan, Dongpeng; Tang, Yanqun; Lin, Heyang; Wang, Dan

    2014-01-01

    Co-assembly of chromophore guests with host matrices can afford materials which have photofunctionalities different from those of individual components. Compared with clay and zeolite materials, the use of metal–organic frameworks (MOFs) as a host structure for fabricating luminescent host–guest materials is still at an early stage. Herein, we report the incorporation of a laser dye, 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM), into stilbene-based and naphthalene-based MOF systems. The resulting materials exhibit blue/red two-color emission, and the intensity ratio of blue to red fluorescence varies in different planes within the MOF crystal as detected by 3D confocal fluorescence microscopy. The observed changes in ratiometric fluorescence suggest the occurrence of energy transfer from MOF host to DCM molecules, which can be further confirmed by periodic density functional theoretical (DFT) calculations. Moreover, selective changes in luminescence behavior are observed on treating the guest@MOF samples with volatile organic compounds (methanol, acetone and toluene), indicating that these host–guest systems have potential applications as fluorescence sensors. It can be expected that by rational selection of MOF hosts and guest chromophores with suitable emissive colors and energy levels, a wide variety of multi-color luminescent and energy-transfer systems can readily be prepared in a similar manner. PMID:24614015

  15. Optimized two-color super resolution imaging of Drp1 during mitochondrial fission with a slow-switching Dronpa variant

    PubMed Central

    Rosenbloom, Alyssa B.; Lee, Sang-Hyuk; To, Milton; Lee, Antony; Shin, Jae Yen; Bustamante, Carlos

    2014-01-01

    We studied the single-molecule photo-switching properties of Dronpa, a green photo-switchable fluorescent protein and a popular marker for photoactivated localization microscopy. We found the excitation light photoactivates as well as deactivates Dronpa single molecules, hindering temporal separation and limiting super resolution. To resolve this limitation, we have developed a slow-switching Dronpa variant, rsKame, featuring a V157L amino acid substitution proximal to the chromophore. The increased steric hindrance generated by the substitution reduced the excitation light-induced photoactivation from the dark to fluorescent state. To demonstrate applicability, we paired rsKame with PAmCherry1 in a two-color photoactivated localization microscopy imaging method to observe the inner and outer mitochondrial membrane structures and selectively labeled dynamin related protein 1 (Drp1), responsible for membrane scission during mitochondrial fission. We determined the diameter and length of Drp1 helical rings encircling mitochondria during fission and showed that, whereas their lengths along mitochondria were not significantly changed, their diameters decreased significantly. These results suggest support for the twistase model of Drp1 constriction, with potential loss of subunits at the helical ends. PMID:25149858

  16. Two-color widefield fluorescence microendoscopy enables multiplexed molecular imaging in the alveolar space of human lung tissue

    NASA Astrophysics Data System (ADS)

    Krstajić, Nikola; Akram, Ahsan R.; Choudhary, Tushar R.; McDonald, Neil; Tanner, Michael G.; Pedretti, Ettore; Dalgarno, Paul A.; Scholefield, Emma; Girkin, John M.; Moore, Anne; Bradley, Mark; Dhaliwal, Kevin

    2016-04-01

    We demonstrate a fast two-color widefield fluorescence microendoscopy system capable of simultaneously detecting several disease targets in intact human ex vivo lung tissue. We characterize the system for light throughput from the excitation light emitting diodes, fluorescence collection efficiency, and chromatic focal shifts. We demonstrate the effectiveness of the instrument by imaging bacteria (Pseudomonas aeruginosa) in ex vivo human lung tissue. We describe a mechanism of bacterial detection through the fiber bundle that uses blinking effects of bacteria as they move in front of the fiber core providing detection of objects smaller than the fiber core and cladding (˜3 μm). This effectively increases the measured spatial resolution of 4 μm. We show simultaneous imaging of neutrophils, monocytes, and fungus (Aspergillus fumigatus) in ex vivo human lung tissue. The instrument has 10 nM and 50 nM sensitivity for fluorescein and Cy5 solutions, respectively. Lung tissue autofluorescence remains visible at up to 200 fps camera acquisition rate. The optical system lends itself to clinical translation due to high-fluorescence sensitivity, simplicity, and the ability to multiplex several pathological molecular imaging targets simultaneously.

  17. Generation of attosecond x-ray pulses with a multi-cycle two-color ESASE scheme

    SciTech Connect

    Ding, Y.; Huang, Z.; Ratner, D.; Bucksbaum, P.; Merdji, H.; /Saclay /SLAC

    2009-03-04

    Generation of attosecond x-ray pulses is attracting much attention within the x-ray free-electron laser (FEL) user community. Several schemes using extremely short laser pulses to manipulate the electron bunches have been proposed. In this paper, we extend the attosecond two-color ESASE scheme proposed by Zholents et al. to the long optical cycle regime using a second detuned laser and a tapered undulator. Both lasers can be about ten-optical-cycles long, with the second laser frequency detuned from the first to optimize the contrast between the central and side current spikes. A tapered undulator mitigates the degradation effect of the longitudinal space charge (LSC) force in the undulator and suppresses the FEL gain of all side current peaks. Simulations using the LCLS parameters show a single attosecond x-ray spike of {approx} 110 attoseconds can be produced. The second laser can also be detuned to coherently control the number of the side x-ray spikes and the length of the radiation pulse.

  18. Single attosecond pulse generation in an orthogonally polarized two-color laser field combined with a static electric field

    SciTech Connect

    Xia Changlong; Zhang Gangtai; Wu Jie; Liu Xueshen

    2010-04-15

    We investigate theoretic high-order harmonic generation and single attosecond pulse generation in an orthogonally polarized two-color laser field, which is synthesized by a mid-infrared (IR) pulse (12.5 fs, 2000 nm) in the y component and a much weaker (12 fs, 800 nm) pulse in the x component. We find that the width of the harmonic plateau can be extended when a static electric field is added in the y component. We also investigate emission time of harmonics in terms of a time-frequency analysis to illustrate the physical mechanism of high-order harmonic generation. We calculate the ionization rate using the Ammosov-Delone-Krainov model and interpret the variation of harmonic intensity for different static electric field strengths. When the ratio of strengths of the static and the y-component laser fields is 0.1, a continuous harmonic spectrum is formed from 220 to 420 eV. By superposing a properly selected range of the harmonic spectrum from 300 to 350 eV, an isolated attosecond pulse with a duration of about 75 as is obtained, which is near linearly polarized.

  19. Proposal of quantitative temperature measurements using two-color technique combined with several infrared radiometers having different detection wavelength bands

    NASA Astrophysics Data System (ADS)

    Inagaki, Terumi; Ishii, Toshimitsu

    2001-03-01

    Infrared thermography has been widely used to visualize a 2D temperature field for various engineering applications. However, in general, conventional infrared thermography cannot directly be applied to quantitative temperature measurement on glossy metal surfaces under near-ambient conditions, because of the severe influence of the reflected energy incident from the surroundings on the measurement. When it is necessary to measure the temperature quantitatively, an appropriate calibration involving complicated procedures must be performed. In this paper, therefore, a new technique of measuring temperature is proposed for near-ambient conditions, by combining simultaneously several infrared radiometers having different detection wavelength bands to enable a two-color technique, which does not require any temperature calibrations. The sensors concerned have a selective wavelength band of several micrometers in width in the range of 2 to 13 micrometers . The applicability of the method, including a series of proposed equations, has been confirmed by an investigation; the numerical simulation presented merely allows a parametric study of how the result varies for different values of emissivity corresponding to a pair of infrared radiometers. An experimental investigation is also performed to estimate or correct the measurement error pertaining to the present technique. This technique has the feature that a 2D temperature field can be evaluated quantitatively, nondestructively, and simultaneously at each picture element without presuming any emissivity and reflectivity, even though the object has a complicated shape; so that it may be useful in various medical or engineering applications.

  20. Orientation dependence of the ionization of CO and NO in an intense femtosecond two-color laser field

    NASA Astrophysics Data System (ADS)

    Li, Hui; Ray, Dipanwita; de, Sankar; Cao, Wei; Laurent, Guillaume; Wang, Zhenhua; Thu Le, Anh; Cocke, C. Lewis; Znakovskaya, Irina; Kling, Matthias

    2012-06-01

    Two-color (800 nm and 400 nm) ultrashort (30±10 fs) laser pulses were used to ionize and dissociate CO and NO. The emission of C^+q, N^+q and O^+ fragments were measured with a velocity-map-imaging (VMI) system. The data show that the ionization rate is dependent on the orientation of the molecules with respect to the laser polarization. Both molecules ionize more easily when the electric field points from C to O in CO and from N to O in NO. The asymmetry of emission is much higher for CO than for NO. The sign of the asymmetry is not strongly dependent on kinetic energy release (KER). The favored ionization orientation is in agreement with the expectation of the molecular orbital Ammosov-Delone-Krainov (MO-ADK) [1] theory and with a Stark-corrected version of a strong-field-approximation (SFA) calculation [2]. [4pt] [1] X.M. Tong, et al., Phys. Rev. A 66, 033402 (2002).[0pt] [2] H. Li, et al., Phys. Rev. A 84, 043429 (2011).

  1. Two-color two-photon excited fluorescence of indole: Determination of wavelength-dependent molecular parameters

    NASA Astrophysics Data System (ADS)

    Herbrich, Sebastian; Al-Hadhuri, Tawfik; Gericke, Karl-Heinz; Shternin, Peter S.; Smolin, Andrey G.; Vasyutinskii, Oleg S.

    2015-01-01

    We present a detailed study of two-color two-photon excited fluorescence in indole dissolved in propylene glycol. Femtosecond excitation pulses at effective wavelengths from 268 to 293.33 nm were used to populate the two lowest indole excited states 1La and 1Lb and polarized fluorescence was then detected. All seven molecular parameters and the two-photon polarization ratio Ω containing information on two-photon absorption dynamics, molecular lifetime τf, and rotation correlation time τrot have been determined from experiment and analyzed as a function of the excitation wavelength. The analysis of the experimental data has shown that 1Lb-1La inversion occurred under the conditions of our experiment. The two-photon absorption predominantly populated the 1La state at all excitation wavelengths but in the 287-289 nm area which contained an absorption hump of the 1Lb state 0-0 origin. The components of the two-photon excitation tensor S were analyzed giving important information on the principal tensor axes and absorption symmetry. The results obtained are in a good agreement with the results reported by other groups. The lifetime τf and the rotation correlation time τrot showed no explicit dependence on the effective excitation wavelength. Their calculated weighted average values were found to be τf = 3.83 ± 0.14 ns and τrot = 0.74 ± 0.06 ns.

  2. SPECTROSCOPIC CONFIRMATION OF UV-BRIGHT WHITE DWARFS FROM THE SANDAGE TWO-COLOR SURVEY OF THE GALACTIC PLANE

    SciTech Connect

    Lepine, Sebastien; Bergeron, P.; Lanning, Howard H.

    2011-03-15

    We present spectroscopic observations confirming the identification of hot white dwarfs among UV-bright sources from the Sandage Two-color Survey of the Galactic Plane and listed in the Lanning (Lan) catalog of such sources. A subsample of 213 UV-bright Lan sources have been identified as candidate white dwarfs based on the detection of a significant proper motion. Spectroscopic observations of 46 candidates with the KPNO 2.1 m telescope confirm 30 sources to be hydrogen white dwarfs with subtypes in the DA1-DA6 range, and with one of the stars (Lan 161) having an unresolved M dwarf as a companion. Five more sources are confirmed to be helium white dwarfs, with subtypes from DB3 to DB6. One source (Lan 364) is identified as a DZ 3 white dwarf, with strong lines of calcium. Three more stars are found to have featureless spectra (to within detection limits) and are thus classified as DC white dwarfs. In addition, three sources are found to be hot subdwarfs: Lan 20 and Lan 480 are classified as sdOB, and Lan 432 is classified sdB. The remaining four objects are found to be field F star interlopers. Physical parameters of the DA and DB white dwarfs are derived from model fits.

  3. Nonsequential double ionization of helium in IR+XUV two-color laser fields: Collision-ionization process

    NASA Astrophysics Data System (ADS)

    Jin, Facheng; Tian, Yuanye; Chen, Jing; Yang, Yujun; Liu, Xiaojun; Yan, Zong-Chao; Wang, Bingbing

    2016-04-01

    We investigate the nonsequential double ionization (NSDI) process of an atom in IR+XUV two-color intense laser fields, where the photon energy of the XUV laser is higher than the atomic ionization threshold. By using the frequency-domain theory, we consider the NSDI as a process caused by the collision-ionization mechanism and obtain the NSDI spectrum that presents a multiplateau structure. With the help of channel analysis, we find that the height of a plateau in the NSDI spectrum is determined by the number of XUV photons absorbed by the electrons. Furthermore, to explain the interference structure in the NSDI spectrum, we also compare the contributions of forward and backward collisions to the NSDI probability. We find that the forward collision dominates the contributions to the NSDI when two electrons are ejected along the same direction and both forward and backward collisions make a comparable contribution to NSDI when the two electrons are ejected along opposite directions. By applying the saddle-point approximation, we obtain an energy-circle formula, which may illustrate the formation of the NSDI spectrum structure.

  4. Measurement of diffusion and thermal diffusion in ternary fluid mixtures using a two-color optical beam deflection technique

    NASA Astrophysics Data System (ADS)

    Königer, A.; Wunderlich, H.; Köhler, W.

    2010-05-01

    We have developed a highly sensitive two-color beam deflection setup to measure diffusion and thermal diffusion in ternary fluid mixtures following a suggestion of Haugen and Firoozabadi [J. Phys. Chem. B 110, 17678 (2006)]. Simultaneous detection of two laser beams with different wavelengths makes it possible to determine the time dependent concentration profiles of all three components. By comparing the measured beam deflection signals to a numerical solution of the coupled heat and mass transport equations, the diffusion matrix, the thermal diffusion, and the Soret coefficients are obtained by a numerical model combined with a nonlinear least-squares fitting routine. The results can be improved by additional thermal diffusion forced Rayleigh scattering experiments, which yield a contrast-weighted average thermal diffusion coefficient. The three Soret coefficients can be obtained independently from the stationary beam deflection amplitudes. Measurements have been performed on the symmetric (equal weight fractions) ternary mixtures dodecane/isobutylbenzene/1,2,3,4-tetrahydronaphthalene and 1-methylnaphthalene/octane/decane. There is only partial agreement between our results and literature data.

  5. Phase structure of two-color QCD at real and imaginary chemical potentials: Lattice simulations and model analyses

    NASA Astrophysics Data System (ADS)

    Makiyama, Takahiro; Sakai, Yuji; Saito, Takuya; Ishii, Masahiro; Takahashi, Junichi; Kashiwa, Kouji; Kouno, Hiroaki; Nakamura, Atsushi; Yahiro, Masanobu

    2016-01-01

    We investigate the phase structure of two-color QCD at both real and imaginary chemical potentials (μ ), performing lattice simulations and analyzing the data with the Polyakov-loop extended Nambu-Jona-Lasinio (PNJL) model. Lattice QCD simulations are done on an 83×4 lattice with the clover-improved two-flavor Wilson fermion action and the renormalization-group-improved Iwasaki gauge action. We test the analytic continuation of physical quantities from imaginary μ to real μ by comparing lattice QCD results calculated at real μ with the results of an analytic function, the coefficients of which are determined from lattice QCD results at imaginary μ . We also test the validity of the PNJL model by comparing model results with lattice QCD ones. The PNJL model is good in the deconfinement region, but less accurate in the transition and confinement regions. This problem is cured by introducing the baryon degree of freedom to the model. It is also found that the vector-type four-quark interaction is necessary to explain lattice data on the quark number density.

  6. Ionization states of heavy elements observed in the 1974 May 14-15 anomalous solar particle event

    NASA Technical Reports Server (NTRS)

    Ma Sung, L. S.; Gloeckler, G.; Fan, C. Y.; Hovestadt, D.

    1981-01-01

    The charge states of heavy ions accelerated in the (He-3)-Fe-rich solar particle event of May 14-15, 1974 have been determined by the use of using data from the University of Maryland/Max-Planck-Institut experiment on IMP 8. In addition to Fe(+11,12), it is found that both O(+5) and Fe(+16,17,18) are also present, suggesting variations in coronal temperatures over a range from approximately 400,000 to 5,000,000 K. The presence of O(+5) and Fe(+16-18) may be explained by a resonant plasma heating mechanism proposed by Fisk (1978) to account for the enhancements of He-3 and Fe.

  7. Sub-micron particle sampler apparatus

    DOEpatents

    Gay, Don D.; McMillan, William G.

    1987-01-01

    Apparatus and method steps for collecting sub-micron sized particles include a collection chamber and cryogenic cooling. The cooling is accomplished by coil tubing carrying nitrogen in liquid form, with the liquid nitrogen changing to the gas phase before exiting from the collection chamber in the tubing. Standard filters are used to filter out particles of diameter greater than or equal to 0.3 microns; however the present invention is used to trap particles of less than 0.3 micron in diameter. A blower draws air to said collection chamber through a filter which filters particles with diameters greater than or equal to 0.3 micron. The air is then cryogenically cooled so that moisture and sub-micron sized particles in the air condense into ice on the coil. The coil is then heated so that the ice melts, and the liquid is then drawn off and passed through a Buchner funnel where the liquid is passed through a Nuclepore membrane. A vacuum draws the liquid through the Nuclepore membrane, with the Nuclepore membrane trapping sub-micron sized particles therein. The Nuclepore membrane is then covered on its top and bottom surfaces with sheets of Mylar.RTM. and the assembly is then crushed into a pellet. This effectively traps the sub-micron sized particles for later analysis.

  8. Method for sampling sub-micron particles

    DOEpatents

    Gay, Don D.; McMillan, William G.

    1985-01-01

    Apparatus and method steps for collecting sub-micron sized particles include a collection chamber and cryogenic cooling. The cooling is accomplished by coil tubing carrying nitrogen in liquid form, with the liquid nitrogen changing to the gas phase before exiting from the collection chamber in the tubing. Standard filters are used to filter out particles of diameter greater than or equal to 0.3 microns; however the present invention is used to trap particles of less than 0.3 micron in diameter. A blower draws air to said collection chamber through a filter which filters particles with diameters greater than or equal to 0.3 micron. The air is then cryogenically cooled so that moisture and sub-micron sized particles in the air condense into ice on the coil. The coil is then heated so that the ice melts, and the liquid is then drawn off and passed through a Buchner funnel where the liquid is passed through a Nuclepore membrane. A vacuum draws the liquid through the Nuclepore membrane, with the Nuclepore membrane trapping sub-micron sized particles therein. The Nuclepore membrane is then covered on its top and bottom surfaces with sheets of Mylar.RTM. and the assembly is then crushed into a pellet. This effectively traps the sub-micron sized particles for later analysis.

  9. Two-color two-photon excited fluorescence of indole: Determination of wavelength-dependent molecular parameters

    SciTech Connect

    Herbrich, Sebastian; Al-Hadhuri, Tawfik; Gericke, Karl-Heinz; Shternin, Peter S. Vasyutinskii, Oleg S.; Smolin, Andrey G.

    2015-01-14

    We present a detailed study of two-color two-photon excited fluorescence in indole dissolved in propylene glycol. Femtosecond excitation pulses at effective wavelengths from 268 to 293.33 nm were used to populate the two lowest indole excited states {sup 1}L{sub a} and {sup 1}L{sub b} and polarized fluorescence was then detected. All seven molecular parameters and the two-photon polarization ratio Ω containing information on two-photon absorption dynamics, molecular lifetime τ{sub f}, and rotation correlation time τ{sub rot} have been determined from experiment and analyzed as a function of the excitation wavelength. The analysis of the experimental data has shown that {sup 1}L{sub b}–{sup 1}L{sub a} inversion occurred under the conditions of our experiment. The two-photon absorption predominantly populated the {sup 1}L{sub a} state at all excitation wavelengths but in the 287–289 nm area which contained an absorption hump of the {sup 1}L{sub b} state 0-0 origin. The components of the two-photon excitation tensor S were analyzed giving important information on the principal tensor axes and absorption symmetry. The results obtained are in a good agreement with the results reported by other groups. The lifetime τ{sub f} and the rotation correlation time τ{sub rot} showed no explicit dependence on the effective excitation wavelength. Their calculated weighted average values were found to be τ{sub f} = 3.83 ± 0.14 ns and τ{sub rot} = 0.74 ± 0.06 ns.

  10. Dual Femtosecond TITANIUM:SAPPHIRE Laser for Ultrafast Optical Sampling Two-Color Pump/probe Studies.

    NASA Astrophysics Data System (ADS)

    Luo, Ningyi Daniel

    A pair of self-synchronous Ti:Sapphire lasers have been setup for two-color pump/probe detection in the sub-picosecond time regime. The two 75 femtosecond self -mode-locked Ti:Sapphire lasers are operated asynchronously at slightly different repetition rates to provide continuously varying dynamic delay times. They are tunable at 700-890 nm. The shorter wavelength pulses from one laser are used as a pump source, while the longer wavelength pulses are used as a probe. The sum-frequency pulses generated by the cross-correlation of the two laser pulses are used to define the "time-zero" position and trigger the pump/probe process. The experiment is triggered at the difference frequency, and the signal can be averaged many times allowing a weak signal to build up. Dual-time scale is involved with the interpretation of the signal, which allows the experiment to be carried on the real time scale and the signal to be recorded on a much reduced equivalent time scale. Excited state lifetime measurement of laser HITCI has proven that this technology is practically feasible. Several advantages have been seen: (1) independent wavelength tunability of the pump and probe lasers; (2) variable femto- to nano -second pump/probe time delay; (3) fast (mu s-ms) data collection time; (4) compact optical layout, without the need for optical delay lines and modulators, and thus, simple optical alignment. This study sheds light on the development of a novel compact high speed optical instrument.

  11. A two-color infrared-vacuum ultraviolet laser pulsed field ionization photoelectron study of NH3.

    PubMed

    Bahng, Mi-Kyung; Xing, Xi; Baek, Sun Jong; Ng, C Y

    2005-08-22

    We have observed fully rotationally resolved transitions of the photoelectron vibrational bands 2(4), 2(5), 1(1)2(1), and 1(1)2(3) for ammonia cation (NH3+) by two-color infrared (IR)-vacuum ultraviolet (VUV)- pulsed field-ionization photoelectron (PFI-PE) measurements. By preparing an intermediate rovibrational state of neutral NH(3) with a known parity by IR excitation followed by VUV-PFI-PE measurements, we show that the photoelectron parity can be determined unambiguously. The IR-VUV-PFI-PE measurement of the 2(4) band clearly reveals the formation of both even and odd l states for the photoelectrons, where l is the orbital angular momentum quantum number. This observation is consistent with the conclusion that the lack of inversion symmetry for NH3 and NH3+ allows odd/even l mixings, rendering the production of both odd and even l states for the photoelectrons. Evidence is also found, indicating that the photoionization transitions with DeltaK=0 are strongly favored compared to that with DeltaK=3. For the 2(5), 1(1)2(1), and 1(1)2(3) bands, only DeltaK=0 transitions for the production of even l photoelectron states from the J'K'=2(0) rotational level of NH3(nu1=1) are observed. The preferential formation of even l photoelectron states for these vibrational bands is attributed to the fact that the DeltaK=0 transitions for the formation of odd l photoelectron states from the 2(0) rotational level of NH3(nu1=1) are suppressed by the constraint of nuclear-spin statistics. In addition to information obtained on the photoionization dynamics of NH3, this experiment also provides a more precise value of 3232+/-10 cm-1 for the nu1+ (N-H stretch) vibrational frequency of NH3+. PMID:16164295

  12. Simultaneous two-phase flow measurement of spray mixing process by means of high-speed two-color PIV

    NASA Astrophysics Data System (ADS)

    Zhang, Ming; Xu, Min; Hung, David L. S.

    2014-09-01

    In this article, a novel high-speed two-color PIV optical diagnostic technique has been developed and applied to simultaneously measure the velocity flow-fields of a multi-hole spark-ignition direct injection (SIDI) fuel injector spray and its ambient gas in a high-pressure constant volume chamber. To allow for the phase discrimination between the fuel droplets and ambient gas, a special tracer-filter system was designed. Fluorescent seeding particles with Sauter mean diameter (SMD) of 4.8 µm were used to trace the gas inside the chamber. With a single high-speed Nd:YLF laser sheet (527 nm) as the incident light source, the Mie-scattering signal marked the phase of the fuel spray, while the fluorescent signal generated from the seeding particles tracked the phase of ambient gas. A high-speed camera, with an image-doubler (mounted in front of the camera lens) that divided the camera pixels into two parts focusing on the same field of view, was used to collect the Mie-scattering signal and LIF (laser induced fluorescence) signal simultaneously with two carefully selected optical filters. To accommodate the large dynamic range of velocities in the two phases (1-2 orders of magnitude difference), two separation times (dt) were introduced. This technique was successfully applied to the liquid spray and ambient gas two-phase flow measurement. The measurement accuracy was compared with those from LDV (laser Doppler velocimetry) measurement and good agreement was obtained. Ambient gas motion surrounding the fuel spray was investigated and characterized into three zones. The momentum transfer process between the fuel spray and ambient gas in each zone was analyzed. The two-phase flow interaction under various superheated conditions was investigated. A strengthened momentum transfer from the liquid spray to the ambient was observed with increased superheat degree.

  13. The 10 micron spectral structure in comets

    NASA Technical Reports Server (NTRS)

    Lynch, David K.; Russell, Ray W.; Campins, Humberto

    1989-01-01

    The 10 micron spectra of comets Halley (1982i), Wilson (1986l), Kohoutek (1973f) and Bradfield (1987s) are presented and compared. The silicate emission profiles of Halley and Bradfield are seen to be remarkably similar in that both contain a sharp break in the spectrum at 11.3 microns. Comet Bradfield does not show the same double peak structure seen in olivine and reported in Comet Halley be Campins and Ryan (1988) and Bregman, et al. (1987). The authors interpret the 11.3 micron signature as being due to olivine-type dust grains with at least some degree of crystallinity. Olivine alone is not enough to reproduce the shape of the 10 micron structure. However, in view of the authors' past success in fitting interstellar dust features with the emissivity profile obtained from amorphous grains produced by laser-vaporizing olivine, this is a very appealing identification. They note that there are significant variations in olivine spectra due to compositional differences, grain size distribution and related grain temperature variations to make the olivine identification tentative. They further tentatively identify the 9.8 micron feature in Halley as being due to either amorphorous olivine or a phyllosilicate (layer lattice). Neither the spectra of Halley, Kohoutek, nor Bradfield exhibited the 12.2 micron feature seen in Comet Wilson, which may prove diagnostic of the composition or thermal history differences between these comets. IR spectra of various mineral samples are discussed in terms of their match to cometary spectra.

  14. Dental plaque, caries prevalence and gingival conditions of 14-15-year-old schoolchildren in Jerash District, Jordan.

    PubMed

    El-Qaderi, S S; Quteish Ta'ani, D

    2006-08-01

    The aim of this cross-sectional study was to evaluate oral hygiene, gingival condition and dental caries prevalence in 14-15-year-old school children in Jerash District, Northern Jordan. Twenty schools (10 male and 10 female schools) with 1362 children of eighth and ninth grades were randomly selected and incorporated in this study. All participants had dental examinations for oral hygiene, gingival condition and dental caries experience using the Silness and Löe Plaque Index (PI), Löe and Silness Gingival Index (GI), and decayed (D), missing (M) and filled (F) teeth (DMFT) and surface (DMFS) codes respectively. The results showed that males had significant lower plaque but significantly higher gingival scores than females (P < 0.001). About 24% of children were caries-free. The proportions of children with one, two or three decayed teeth were between 10% and 18%. Slight non-significant variations between males and females were observed in regard to DMFT/S and their components (P < 0.05). It is concluded that significant gender variations were noted in PI and GI scores but not in DMFT/S or their components. However, the values of these clinical scores were lower than those results previously reported in northern Jordan. PMID:16958744

  15. New even-parity high-lying levels of Sm I and measurement of isotope shifts by two-color resonance ionization mass spectrometry

    NASA Astrophysics Data System (ADS)

    Seema, A. U.; Mandal, P. K.; Rath, Asawari D.; Dev, Vas

    2014-09-01

    In this work, we investigate the even-parity high-lying levels of Sm I in the energy region 33136-33960 cm-1 by performing two-color three-photon resonance ionization spectroscopy in an atomic beam coupled to a time-of-flight mass spectrometer using two tunable pulsed dye lasers. We observe twenty-one new and confirm eight previously reported even-parity energy levels of Sm I in this spectral region. Absolute energies of these levels are determined with an accuracy of ±0.3 cm-1. Using electric dipole selection rule, total angular momentum (J-value) of the most newly observed levels is assigned uniquely. Further, employing two-color three-step resonance ionization mass spectrometry, we measure the isotope shift between 154Sm and 144Sm of sixteen high-lying levels with a moderate accuracy of ±30 mK.

  16. Bright attosecond soft X-ray pulse trains by transient phase-matching in two-color high-order harmonic generation.

    PubMed

    Schütte, Bernd; Weber, Paul; Kovács, Katalin; Balogh, Emeric; Major, Balázs; Tosa, Valer; Han, Songhee; Vrakking, Marc J J; Varjú, Katalin; Rouzée, Arnaud

    2015-12-28

    We study two-color high-order harmonic generation in Neon with 790 nm and 1300 nm driving laser fields and observe an extreme-ultraviolet continuum that extends to photon energies of 160 eV. Using a 6-mm-long, high pressure gas cell, we optimize the HHG yield at high photon energies and investigate the effect of ionization and propagation under phase-matching conditions that allow us to control the temporal structure of the XUV emission. Numerical simulations that include the 3D propagation of the two-color laser pulse show that a bright isolated attosecond pulse with exceptionally high photon energies can be generated in our experimental conditions due to an efficient hybrid optical and phase-matching gating mechanism. PMID:26832053

  17. Calibration of a high spatial resolution laser two-color heterodyne interferometer for density profile measurements in the TJ-II stellarator

    SciTech Connect

    Acedo, Pablo; Pedreira, P.; Criado, A. R.; Lamela, Horacio; Sanchez, Miguel; Sanchez, Joaquin

    2008-10-15

    A high spatial resolution two-color (CO{sub 2}, {lambda}=10.6 {mu}m, He-Ne, {lambda}=633 nm) interferometer for density profile measurements in the TJ-II stellarator is under development and installation, based in the currently operational single channel two-color heterodyne interferometer. To achieve the objectives of 32 channels, with 4-5 mm lateral separation between plasma chords, careful design and calibration of the interferometric waveforms for both the measurement and vibration compensation wavelengths are undertaken. The first step has been to set up in our laboratories an expanded-beam heterodyne/homodyne interferometer to evaluate the quality of both interferometric wavefronts, a reported source of poor vibration compensation and thus low resolution in the density profile measurements. This novel interferometric setup has allowed us to calibrate the spatial resolution in the profile measurements resulting in {approx}2 mm lateral resolution in the reconstruction of the interferometric wavefront.

  18. Dynamics of the formation of laser-induced periodic surface structures (LIPSS) upon femtosecond two-color double-pulse irradiation of metals, semiconductors, and dielectrics

    NASA Astrophysics Data System (ADS)

    Höhm, S.; Herzlieb, M.; Rosenfeld, A.; Krüger, J.; Bonse, J.

    2016-06-01

    In order to address the dynamics and physical mechanisms of LIPSS formation for three different classes of materials (metals, semiconductors, and dielectrics), two-color double-fs-pulse experiments were performed on Titanium, Silicon and Fused Silica. For that purpose a Mach-Zehnder interferometer generated polarization controlled (parallel or cross-polarized) double-pulse sequences at 400 nm and 800 nm wavelength, with inter-pulse delays up to a few picoseconds. Multiple of these two-color double-pulse sequences were collinearly focused by a spherical mirror to the sample surfaces. The fluence of each individual pulse (400 nm and 800 nm) was always kept below its respective ablation threshold and only the joint action of both pulses lead to the formation of LIPSS. Their resulting characteristics (periods, areas) were analyzed by scanning electron microscopy. The periods along with the LIPSS orientation allow a clear identification of the pulse which dominates the energy coupling to the material. For strong absorbing materials (Silicon, Titanium), a wavelength-dependent plasmonic mechanism can explain the delay-dependence of the LIPSS. In contrast, for dielectrics (Fused Silica) the first pulse always dominates the energy deposition and LIPSS orientation, supporting a non-plasmonic formation scenario. For all materials, these two-color experiments confirm the importance of the ultrafast energy deposition stage for LIPSS formation.

  19. How do we select multiple features? Transient costs for selecting two colors rather than one, persistent costs for color-location conjunctions.

    PubMed

    Lo, Shih-Yu; Holcombe, Alex O

    2014-02-01

    In a previous study Lo, Howard, & Holcombe (Vision Research 63:20-33, 2012), selecting two colors did not induce a performance cost, relative to selecting one color. For example, requiring possible report of both a green and a red target did not yield a worse performance than when both targets were green. Yet a cost of selecting multiple colors was observed when selection needed be contingent on both color and location. When selecting a red target to the left and a green target to the right, superimposing a green distractor to the left and a red distractor to the right impeded performance. Possibly, participants cannot confine attention to a color at a particular location. As a result, distractors that share the target colors disrupt attentional selection of the targets. The attempt to select the targets must then be repeated, which increases the likelihood that the trial terminates when selection is not effective, even for long trials. Consistent with this, here we find a persistent cost of selecting two colors when the conjunction of color and location is needed, but the cost is confined to short exposure durations when the observer just has to monitor red and green stimuli without the need to use the location information. These results suggest that selecting two colors is time-consuming but effective, whereas selection of simultaneous conjunctions is never entirely successful. PMID:24249221

  20. Exploratory 5-micron spectrum of Uranus

    SciTech Connect

    Orton, G.S.; Kaminski, C.D.

    1989-01-01

    The intensity peak at 4.8 microns characterizing the spectrum observed for the disk of Uranus near 5 microns, in June 1987, exhibits steep declines at shorter and longer wavelength. An exploratory discussion is presented of various models in view of these data; it is noted that some component of the radiation must originate near the 140 K atmospheric irrespective of the radiation's origin in sunlight or thermal emission; physical considerations dictate that it be at least partly thermal in origin. One model consistent with the data requires the presence of a cloud top at the 8-bar level. 30 references.

  1. Proceedings of the National Conference on Population Library and Information Services (3rd Chapel Hill, N. C., May 14-15, 1970)

    ERIC Educational Resources Information Center

    Kellermann, Priscilla

    Contains the proceedings of the Third National Conference on Population Library and Information Services held in Chapel Hill, North Carolina, May 14-15, 1970. Under the joint sponsorship of the Carolina Population Center and the Population Council of New York, this was the third in a series of annual conference/workshops devoted to library and…

  2. Perfecting the Formula: Effective Strategies = Educational Success. A Report from the 2009 Governors Education Symposium (Cary, North Carolina, June 14-15, 2009)

    ERIC Educational Resources Information Center

    NGA Center for Best Practices, 2009

    2009-01-01

    The 2009 "Governors Education Symposium" was co-hosted by the James B. Hunt, Jr. Institute for Educational Leadership and Policy and the National Governors Association Center for Best Practices on June 14-15, 2009, in Cary, North Carolina. Vermont Governor Jim Douglas and former North Carolina Governor Jim Hunt served as co-chairs. This year's…

  3. University-School Partnerships: Polymer Chemistry Days Run at a University for 14-15 Year Olds and Their Impact on Attitudes to Science

    ERIC Educational Resources Information Center

    Shaw, A. J.; Harrison, T. G.; Medley, M. I.; Sellou, L.; Shallcross, K. L.; Croker, S. J.; Williams, S. J.; Shallcross, D. E.

    2010-01-01

    Polymer Chemistry days run by Bristol ChemLabS at the School of Chemistry, University of Bristol for year 10 (14-15 year olds) school students are described. Pre and post questionnaires were analysed to determine the impact on attitudes to science. There was no change in attitudes to the importance of science or practical work in science, but…

  4. Origin of the Apollo 14, 15, and 17 yellow ultramafic glasses by mixing of deep cumulate remelts

    NASA Astrophysics Data System (ADS)

    Brown, S. M.; Grove, T. L.

    2015-12-01

    We examine the fO2-dependent melting conditions of the Apollo 14 yellow intermediate-Ti ultramafic glasses and the melting processes that formed the full suite of lunar yellow ultramafic glasses. Multiple saturation experiments indicate that the Apollo 14 yellow glass would have been in equilibrium with residual olivine and low-Ca pyroxene near 1530 °C and 2.4 GPa at ΔIW = +2. At ΔIW = -2, the multiple saturation point moves to greater depth and higher temperature to 1580 °C and 3.0 GPa. Combining the results of this study with that of Krawczynski and Grove (2012) on more Ti-rich Apollo orange and red glass indicates that the fO2-induced change in multiple saturation pressure correlates with the Fe-Ti# (molar (FeO + TiO2*)/(MgO + FeO + TiO2*), where TiO2* = all Ti calculated as Ti4+) of the liquid. Further, a decrease in the olivine Fe-Mg exchange coefficient at lower fO2 suggests that Fe2+ is complexing more efficiently with Ti3+ at the expense of Mg in the melt than it did with Ti4+ at higher fO2. Processes involving assimilation and/or fractionation and/or melt-wall rock reaction all fail to produce the within-suite compositional variability observed in the Apollo 14, 15, and 17 yellow glasses. Mixing of remelted source cumulates, combined with small amounts of olivine fractionation, are the only mechanisms that can reproduce all three trends. We present a quantitative model of the mixing process with simultaneous olivine fractionation. Remarkably, the trends can be explained by mixing melts of an ultramafic source (olivine + pigeonite or orthopyroxene), a clinopyroxene + ilmenite bearing cumulate, and KREEP. Lunar mantle overturn is the most likely process that can reconcile the observed major and trace element compositional characteristics and the experimental results. These two constraints are consistent with different models of lunar magma ocean crystallization (Snyder et al., 1992; Eklins-Tanton et al., 2011). A complex, hot thermal history is necessary

  5. Application of coherent 10 micron imaging lidar

    SciTech Connect

    Simpson, M.L.; Hutchinson, D.P.; Richards, R.K.; Bennett, C.A.

    1997-04-01

    With the continuing progress in mid-IR array detector technology and high bandwidth fan-outs, i.f. electronics, high speed digitizers, and processing capability, true coherent imaging lidar is becoming a reality. In this paper experimental results are described using a 10 micron coherent imaging lidar.

  6. Efavirenz Dissolution Enhancement I: Co-Micronization

    PubMed Central

    da Costa, Maíra Assis; Seiceira, Rafael Cardoso; Rodrigues, Carlos Rangel; Hoffmeister, Cristiane Rodrigues Drago; Cabral, Lucio Mendes; Rocha, Helvécio Vinícius Antunes

    2012-01-01

    AIDS constitutes one of the most serious infectious diseases, representing a major public health priority. Efavirenz (EFV), one of the most widely used drugs for this pathology, belongs to the Class II of the Biopharmaceutics Classification System for drugs with very poor water solubility. To improve EFV’s dissolution profile, changes can be made to the physical properties of the drug that do not lead to any accompanying molecular modifications. Therefore, the study objective was to develop and characterize systems with efavirenz able to improve its dissolution, which were co-processed with sodium lauryl sulfate (SLS) and polyvinylpyrrolidone (PVP). The technique used was co-micronization. Three different drug:excipient ratios were tested for each of the two carriers. The drug dispersion dissolution results showed significant improvement for all the co-processed samples in comparison to non-processed material and corresponding physical mixtures. The dissolution profiles obtained for dispersion with co-micronized SLS samples proved superior to those of co-micronized PVP, with the proportion (1:0.25) proving the optimal mixture. The improvements may be explained by the hypothesis that formation of a hydrophilic layer on the surface of the micronized drug increases the wettability of the system formed, corroborated by characterization results indicating no loss of crystallinity and an absence of interaction at the molecular level. PMID:24300394

  7. Sub-micron particle sampler apparatus and method for sampling sub-micron particles

    DOEpatents

    Gay, D.D.; McMillan, W.G.

    1984-04-12

    Apparatus and method steps for collecting sub-micron sized particles include a collection chamber and cryogenic cooling. The cooling is accomplished by coil tubing carrying nitrogen in liquid form, with the liquid nitrogen changing to the gas phase before exiting from the collection chamber in the tubing. Standard filters are used to filter out particles of diameter greater than or equal to 0.3 microns; however, the present invention is used to trap particles of less than 0.3 micron in diameter. A blower draws air to said collection chamber through a filter which filters particles with diameters greater than or equal to 0.3 micron. The air is then cryogenically cooled so that moisture and sub-micron sized particles in the air condense into ice on the coil. The coil is then heated so that the ice melts, and the liquid is then drawn off and passed through a Buchner funnel where the liquid is passed through a Nuclepore membrane. A vacuum draws the liquid through the Nuclepore membrane, with the Nuclepore membrane trapping sub-micron sized particles therein. The Nuclepore membrane is then covered on its top and bottom surfaces with sheets of Mylar and the assembly is then crushed into a pellet. This effectively traps the sub-micron sized particles for later analysis. 6 figures.

  8. The 11 Micron Emissions of Carbon Stars

    NASA Astrophysics Data System (ADS)

    Goebel, J. H.; Cheeseman, P.; Gerbault, F.

    1995-08-01

    A new classification scheme of the IRAS LRS carbon stars is presented. It comprises the separation of 718 probable carbon stars into 12 distinct self-similar spectral groupings. Continuum temperatures are assigned and range from 470 to 5000 K. Three distinct dust species are identifiable: SiC, α: C-H, and MgS. In addition to the narrow 11+ microns emission feature that is commonly attributed to SiC, a broad 11+ microns emission feature, that is correlated with the 8.5 and 7.7 microns features, is found and attributed to α:C-H. SiC and α:C-H band strengths are found to correlate with the temperature progression among the Classes. We find a spectral sequence of Classes that reflects the carbon star evolutionary sequence of spectral types, or alternatively developmental sequences of grain condensation in carbon-rich circumstellar shells. If decreasing temperature corresponds to increasing evolution, then decreasing temperature corresponds to increasing C/O resulting in increasing amounts of carbon rich dust, namely α: C-H. If decreasing the temperature corresponds to a grain condensation sequence, then heterogeneous, or induced nucleation scenarios are supported. SiC grains precede α: C-H and form the nuclei for the condensation of the latter material. At still lower temperatures, MgS appears to be quite prevalent. No 11.3 microns PAH features are identified in any of the 718 carbon stars. However, one of the coldest objects, IRAS 15048-5702, and a few others, displays an 11.9 microns emission feature characteristic of laboratory samples of coronene. That feature corresponds to the C-H out of plane deformation mode of aromatic hydrocarbon. This band indicates the presence of unsaturated, sp3, hydrocarbon bonds that may subsequently evolve into saturated bonds, sp2, if, and when, the star enters the planetary nebulae phase of stellar evolution. The effusion of hydrogen from the hydrocarbon grain results in the evolution in wavelength of this 11.9 microns emission

  9. The 11 Micron Emissions of Cabon Stars

    NASA Technical Reports Server (NTRS)

    Goebel, J. H.; Cheeseman, P.; Gerbault, F.

    1995-01-01

    A new classification scheme of the IRAS LRS carbon stars is presented. It comprises the separation of 718 probable carbon stars into 12 distinct self-similar spectral groupings. Continuum temperatures are assigned and range from 470 to 5000 K. Three distinct dust species are identifiable: SiC, alpha:C-H, and MgS. In addition to the narrow 11 + micron emission feature that is commonly attributed to SiC, a broad 11 + micron emission feature, that is correlated with the 8.5 and 7.7 micron features, is found and attributed to alpha:C-H. SiC and alpha:C-H band strengths are found to correlate with the temperature progression among the Classes. We find a spectral sequence of Classes that reflects the carbon star evolutionary sequence of spectral types, or alternatively developmental sequences of grain condensation in carbon-rich circumstellar shells. If decreasing temperature corresponds to increasing evolution, then decreasing temperature corresponds to increasing CIO resulting in increasing amounts of carbon rich dust, namely alpha:C-H. If decreasing the temperature corresponds to a grain condensation sequence, then heterogeneous, or induced nucleation scenarios are supported. SiC grains precede alpha:C-H and form the nuclei for the condensation of the latter material. At still lower temperatures, MgS appears to be quite prevalent. No 11.3 micron PAH features are identified in any of the 718 carbon stars. However, one of the coldest objects, IRAS 15048-5702, and a few others, displays an 11.9 micron emission feature characteristic of laboratory samples of coronene. That feature corresponds to the C-H out of plane deformation mode of aromatic hydrocarbon. This band indicates the presence of unsaturated, sp(sup 3), hydrocarbon bonds that may subsequently evolve into saturated bonds, sp(sup 2), if, and when, the star enters the planetary nebulae phase of stellar evolution. The effusion of hydrogen from the hydrocarbon grain results in the evolution in wavelength of this

  10. The 11 Micron Emissions of Carbon Stars

    NASA Technical Reports Server (NTRS)

    Goebel, J. H.; Cheeseman, P.; Gerbault, F.

    1995-01-01

    A new classification scheme of the IRAS LRS carbon stars is presented. It comprises the separation of 718 probable carbon stars into 12 distinct self-similar spectral groupings. Continuum temperatures are assigned and range from 470 to 5000 K. Three distinct dust species are identifiable: SiC, alpha:C-H, and MgS. In addition to the narrow 11 + micron emission feature that is commonly attributed to SiC, a broad 11 + micron emission feature, that is correlated with the 8.5 and 7.7 micron features, is found and attributed to alpha:C-H. SiC and alpha:C-H band strengths are found to correlate with the temperature progression among the Classes. We find a spectral sequence of Classes that reflects the carbon star evolutionary sequence of spectral types, or alternatively developmental sequences of grain condensation in carbon-rich circumstellar shells. If decreasing temperature corresponds to increasing evolution, then decreasing temperature corresponds to increasing C/O resulting in increasing amounts of carbon rich dust, namely alpha:C-H. If decreasing the temperature corresponds to a grain condensation sequence, then heterogeneous, or induced nucleation scenarios are supported. SiC grains precede alpha:C-H and form the nuclei for the condensation of the latter material. At still lower temperatures, MgS appears to be quite prevalent. No 11.3 micron PAH features are identified in any of the 718 carbon stars. However, one of the coldest objects, IRAS 15048-5702, and a few others, displays an 11.9 micron emission feature characteristic of laboratory samples of coronene. That feature corresponds to the C-H out of plane deformation mode of aromatic hydrocarbon. This band indicates the presence of unsaturated, sp(sup 3), hydrocarbon bonds that may subsequently evolve into saturated bonds, sp(sup 2), if, and when, the star enters the planetary nebulae phase of stellar evolution. The effusion of hydrogen from the hydrocarbon grain results in the evolution in wavelength of this

  11. Shallow and peripheral volcanic sources of inflation revealed by modeling two-color geodimeter and leveling data from Long Valley caldera, California, 1988-1992

    SciTech Connect

    Langbein, J.; Dzurisin, D.; Marshall, G.

    1995-07-10

    The authors refined the model for inflation of the Long Valley caldera near Mammoth Lakes, California, by combining both geodetic measurements of baseline length and elevation changes. Baseline length changes measured using a two-color geodimeter with submillimeter precision revealed that the resurgent dome started to reinflate in late 1989. Measurements between late 1989 and mid-1992 revealed nearly 13 cm of extension across the resurgent dome. Geodetic leveling surveys with approximately 2-mm precision made in late 1988 and in mid-1992 revealed a maximum of about 8 cm of uplift of the resurgent dome. Two elliposidal sources satisfy both the leveling and two-color measurements, whereas spherical point sources could not. The model`s primary inflation source is located 5.5 km beneath the resurgent dome with the two horizontal axes. A second source was added to improve the fit to the two-color measurements. This secondary source is located at a depth between 10 and 20 km beneath the south moat of the caldera and has the geometry of an elongated ellipsoid or pipe that dips down to the northeast. In addition, the leveling data suggest dike intrusion beneath Mammoth Mountain during the 1988-1992 interval, which is likely associated with an intense swarm of small earthquakes during the summer of 1989 at that location. The authors analysis shows the dike intrusion to be the shallowest of the three sources with a depth range of 1-3 km below the surface to the top of the intrusion. 18 refs., 4 figs., 2 tabs.

  12. 8- to 13-micron spectra of asteroids

    NASA Astrophysics Data System (ADS)

    Green, S. F.; Eaton, N.; Aitken, D. K.; Roche, P. F.; Meadows, A. J.

    1985-05-01

    It is pointed out that thermal emission from asteroids reaches a maximum in the 10- to 20-micron region. In connection with the present investigation, a uniform set of spectra was obtained in the 8- to 13-micron region for 12 asteroids (together with additional observations of 19 Fortuna). These spectra provide a potentially valuable data set for future use (e.g., with IRAS data). The main conclusion from the obtained results is that diagnostic emission features of the type observed by Feierberg et al. (1983) are not common in C- and M-type asteroids. Optical studies of 19 Fortuna do not reveal any unusual properties which distinguish it from other C-type asteroids observed.

  13. A folded-sandwich polarization-entangled two-color photon pair source with large tuning capability for applications in hybrid quantum systems

    NASA Astrophysics Data System (ADS)

    Dietz, Otto; Müller, Chris; Kreißl, Thomas; Herzog, Ulrike; Kroh, Tim; Ahlrichs, Andreas; Benson, Oliver

    2016-02-01

    We demonstrate a two-color entangled photon pair source which can be adapted easily to a wide range of wavelength combinations. A Fresnel rhomb as a geometrical quarter-wave plate and a versatile combination of compensation crystals are key components of the source. Entanglement of two photons at the Cs D1 line (894.3 nm) and at the telecom O-band (1313.1 nm) with a fidelity of F=0.753 ± 0.021 is demonstrated, and improvements of the setup are discussed.

  14. Supersonic Flows in Micron-Sized Geometries

    NASA Astrophysics Data System (ADS)

    Bayt, Robert; Breuer, Kenneth

    1998-11-01

    The results of experiments and numerical simulations of flows in micromachined converging-diverging nozzles are presented. The nozzles are fabricated using deep Reactive Ion Etching (DRIE) and are typically 20-30 microns at the throat with expansion ratios ranging from 5 to 20. The flow channels are 300 microns deep, resulting in a 10:1 or better aspect ratio at the throat. Experimental measurements of mass flow and thrust vs. pressure ratio are presented demonstrating the presence of choked and supersonic flow in the micron-scale gemoetries. Mass flow and thrust efficiencies are also presented and compared with results from two-dimensional Navier-Stokes simulations. It is found that, while the efficiencies are reasonably large (much better than one might expect, considering the small dimension of the nozzles), the boundary layers have a considerable effect, particularly on the thrust efficiency of the device, due to the relatively large displacement thickness which reduces the effective expansion ratio. The boundary layers at the top and bottom of the nozzles also affect the performance, particularly at low Reynolds numbers. Additional experimental and numerical results are also discussed.

  15. MIDCOURSE SPACE EXPERIMENT VERSUS IRAS TWO-COLOR DIAGRAMS AND THE CIRCUMSTELLAR ENVELOPE-SEQUENCE OF OXYGEN-RICH LATE-TYPE STARS

    SciTech Connect

    Sjouwerman, Lorant O.; Capen, Stephanie M.; Claussen, Mark J. E-mail: stephanie.m.capen@enc.ed

    2009-11-10

    We present Midcourse Space Experiment (MSX) two-color diagrams that can be used to characterize circumstellar environments of sources with good quality MSX colors in terms of IRAS color regions for oxygen-rich stars. With these diagrams, we aim to provide a new tool that can be used to study circumstellar environments and to improve detection rates for targeted surveys for circumstellar maser emission similar to the IRAS two-color diagram. This new tool is especially useful for regions in the sky where IRAS was confused, in particular in the Galactic plane and bulge region. Unfortunately, using MSX colors alone does not allow one to distinguish between carbon-rich and oxygen-rich objects. An application of this tool on 86 GHz SiO masers shows that for this type of masers an instantaneous detection rate of 60% to 80% can be achieved if target sources are selected according to MSX color (region). Our investigations may have revealed an error in the MSX point source catalog version 2.3. That is, the photometry of the 21.3 mum (MSX E filter) band for most weak 8.28 mum (or MSX A filter) band sources seems off by about a factor 2 (0.5-1 mag too bright).

  16. Searching for New Physics from 20 microns to a micron and below

    NASA Astrophysics Data System (ADS)

    Geraci, Andrew; Smullin, Sylvia; Weld, David; Kapitulnik, Aharon; Dimopoulos, Savas

    2004-05-01

    Several recent theoretical ideas suggest that new physics related to gravity may appear at short length scales. For example, light moduli or particles in "large" extra dimensions could mediate macroscopic forces of (super)gravitational strength at length scales below a millimeter. At the 20 microns level, I will discuss the Stanford cantilever experiment (J. Chiaverini, S. J. Smullin, A. A. Geraci, D. M. Weld, A. Kapitulnik, Phys.Rev.Lett. 90, 151101 (2003).), including an improvement involving a magnetic analog which allows force calibration and precision alignment to reduce systematics. I will also discuss some experimental challenges at length scales below a few microns including the Casimir/Van der Waals background, and will describe an experimental prospect to search for new (sub)-micron forces using arrays of trapped Bose-Einstein condensed atoms (Savas Dimopoulos and Andrew A. Geraci, Phys. Rev. D 68, 124021 (2003). ).

  17. Novel Tests of Gravity Below Fifty Microns

    NASA Astrophysics Data System (ADS)

    Martinez, Gabriela; Johnson, Jeremy; Guerrero, Ian; Hoyle, C. D.

    2016-03-01

    Due to inconsistencies between General Relativity and the Standard Model, tests of gravity remain at the forefront of experimental physics. At Humboldt State University, undergraduates and faculty are designing an experiment sensitive enough to detect gravitational interactions below the 50 micron scale. The experiment measures the twist of a torsion pendulum as an attractor mass is oscillated nearby in a parallel plate configuration, providing time varying gravitational torque on the pendulum. The size and distance dependence of the torque variation will provide a means to determine any deviation from current models of gravity on untested scales. Supported by NSF Grants 1065697 and 1306783.

  18. Optical isolators for 2-micron fibre lasers

    NASA Astrophysics Data System (ADS)

    Stevens, Gary; Legg, Thomas H.; Shardlow, Peter

    2015-02-01

    We report on the development and testing of optical isolators for use in 2-micron fiber laser systems. A variety of potential Faraday rotator materials were characterised to identify the most suitable materials for use in the 1700-2100nm wavelength range. Isolators based on the three best performing materials were then developed and packaged as fiber-in, fiber-out and fiber-in, beam-out devices. The isolators were then tested in CW, pulsed and ultrafast laser systems. The three different designs produced different performance characteristics, but all designs demonstrated isolation >25dB and insertion losses of <1.2 dB.

  19. The Two Micron All Sky Survey

    NASA Astrophysics Data System (ADS)

    Kleinmann, S. G.; Lysaght, M. G.; Pughe, W. L.; Schneider, S. E.; Skrutskie, M. F.; Weinberg, M. D.; Price, S. D.; Matthews, K.; Soifer, B. T.; Huchra, J. P.

    1994-07-01

    The Two Micron All Sky Survey (2MASS) will provide a uniform survey of the entire sky at three near-infrared wavebands: J(lambdaeff = 1.25 micrometers), H(lambdaeff = 1.65 micrometers), and Ks(lambdaeff = 2.16 micrometers). A major goal of the survey is to probe large scale structures in the Milky Way and in the Local Universe, exploiting the relatively high transparency of the interstellar medium in the near-infrared, and the high near-infrared luminosities of evolved low- and intermediate-mass stars. A sensitive overview of the near-infrared sky is also an essential next step to maximize the gains achievable with infrared array technology. Our assessment of the astrophysical questions that might be addressed with these new arrays is currently limited by the very bright flux limit of the only preceding large scale near-infrared sky survey, the Two Micron Sky Survey carried out at Caltech in the late 1960's. Near-infrared instruments based on the new array technology have already obtained spectra of objects 1 million times fainter than the limit of the TMSS] This paper summarizes the essential parameters of the 2MASS project and the rationale behind those choices, and gives an overview of results obtained with a prototype camera that has been in operation since May 1992. We conclude with a list of expected data products and a statement of the data release policy.

  20. Digital mammography: tradeoffs between 50- and 100-micron pixel size

    NASA Astrophysics Data System (ADS)

    Freedman, Matthew T.; Steller Artz, Dorothy E.; Jafroudi, Hamid; Lo, Shih-Chung B.; Zuurbier, Rebecca A.; Katial, Raj; Hayes, Wendelin S.; Wu, Chris Y.; Lin, Jyh-Shyan; Steinman, Richard M.; Tohme, Walid G.; Mun, Seong K.

    1995-05-01

    Improvements in mammography equipment related to a decrease in pixel size of digital mammography detectors raise questions of the possible effects of these new detectors. Mathematical modeling suggested that the benefits of moving from 100 to 50 micron detectors were slight and might not justify the cost of these new units. Experiments comparing screen film mammography, a storage phosphor 100 micron digital detector, a 50 micron digital breast spot device, 100 micron film digitization and 50 micron film digitization suggests that object conspicuity should be better for digital compared to conventional systems, but that there seemed to be minimal advantage to going from 100 to 50 microns. The 50 micron pixel system appears to provide a slight advantage in object contrast and perhaps in shape definition, but did not allow smaller objects to be detected.

  1. Development of a simultaneous two-color near-infrared multi-object spectrograph SWIMS for the TAO 6.5-m telescope

    NASA Astrophysics Data System (ADS)

    Motohara, Kentaro; Konishi, Masahiro; Takahashi, Hidenori; Tateuchi, Ken; Kitagawa, Yutaro; Todo, Soya; Kato, Natsuko M.; Ohsawa, Ryou; Aoki, Tsutomu; Asano, Kentaro; Doi, Mamoru; Kamizuka, Takafumi; Kawara, Kimiaki; Kohno, Kotaro; Koshida, Shintaro; Minezaki, Takeo; Miyata, Takashi; Morokuma, Tomoki; Okada, Kazushi; Sako, Shigeyuki; Soyano, Takao; Tamura, Yoichi; Tanabe, Toshihiko; Tanaka, Masuo; Tarusawa, Ken'ichi; Uchiyama, Mizuho; Yoshii, Yuzuru

    2014-07-01

    Simultaneous Color Wide-field Infrared Multi-object Spectrograph, SWIMS, is one of the first generation in- struments for the University of Tokyo Atacama Observatory (TAO) 6.5m Telescope now under construction. A dichroic mirror being inserted in the collimated beam, it is capable of two-color simultaneous imaging with FoV of 9:16φ or R ˜ 1000 multi-object spectroscopy at 0.9-2.5μm wavelength range in one shot, and enables us to carry out efficient NIR imaging/spectroscopic survey of objects such as distant galaxies and young stellar objects. All the major components have been fabricated and we will start integration and laboratory cool-down test in the summer of 2014. After the engineering and initial science observations at the Subaru telescope, SWIMS will be transported to TAO telescope and see the first light in 2018.

  2. Generation of Bright, Spatially Coherent Soft X-Ray High Harmonics in a Hollow Waveguide Using Two-Color Synthesized Laser Pulses.

    PubMed

    Jin, Cheng; Stein, Gregory J; Hong, Kyung-Han; Lin, C D

    2015-07-24

    We investigate the efficient generation of low-divergence high-order harmonics driven by waveform-optimized laser pulses in a gas-filled hollow waveguide. The drive waveform is obtained by synthesizing two-color laser pulses, optimized such that highest harmonic yields are emitted from each atom. Optimization of the gas pressure and waveguide configuration has enabled us to produce bright and spatially coherent harmonics extending from the extreme ultraviolet to soft x rays. Our study on the interplay among waveguide mode, atomic dispersion, and plasma effect uncovers how dynamic phase matching is accomplished and how an optimized waveform is maintained when optimal waveguide parameters (radius and length) and gas pressure are identified. Our analysis should help laboratory development in the generation of high-flux bright coherent soft x rays as tabletop light sources for applications. PMID:26252685

  3. Kinetic study of terahertz generation based on the interaction of two-color ultra-short laser pulses with molecular hydrogen gas

    NASA Astrophysics Data System (ADS)

    Soltani Gishini, M. S.; Ganjovi, A.; Saeed, M.

    2016-06-01

    In this work, using a two dimensional particle in cell-Monte Carlo collision simulation scheme, interaction of two-color ultra-short laser pulses with the molecular hydrogen gas (H2) is examined. The operational laser parameters, i.e., its pulse shape, duration, and waist, are changed and, their effects on the density and kinetic energy of generated electrons, THz electric field, intensity, and spectrum are studied. It is seen that the best pulse shape generating the THz signal radiation with the highest intensity is a trapezoidal pulse, and the intensity of generated THz radiation is increased at the higher pulse durations and waists. For all the operational laser parameters, the maximum value of emitted THz signal frequency always remains lower than 5 THz. The intensity of applied laser pulses is taken about 1014 w/cm2, and it is observed that while a small portion of the gaseous media gets ionized, the radiated THz signal is significant.

  4. Emergence of electron coherence and two-color all-optical switching in MoS2 based on spatial self-phase modulation

    PubMed Central

    Wu, Yanling; Wu, Qiong; Sun, Fei; Cheng, Cai; Meng, Sheng; Zhao, Jimin

    2015-01-01

    Generating electron coherence in quantum materials is essential in optimal control of many-body interactions and correlations. In a multidomain system this signifies nonlocal coherence and emergence of collective phenomena, particularly in layered 2D quantum materials possessing novel electronic structures and high carrier mobilities. Here we report nonlocal ac electron coherence induced in dispersed MoS2 flake domains, using coherent spatial self-phase modulation (SSPM). The gap-dependent nonlinear dielectric susceptibility χ(3) measured is surprisingly large, where direct interband transition and two-photon SSPM are responsible for excitations above and below the bandgap, respectively. A wind-chime model is proposed to account for the emergence of the ac electron coherence. Furthermore, all-optical switching is achieved based on SSPM, especially with two-color intraband coherence, demonstrating that electron coherence generation is a ubiquitous property of layered quantum materials. PMID:26351696

  5. Efficient three-step, two-color ionization of plutonium using a resonance enhanced 2-photon transition into an autoionizing state

    NASA Astrophysics Data System (ADS)

    Kunz, P.; Huber, G.; Passler, G.; Trautmann, N.

    2004-05-01

    Resonance ionization mass spectrometry (RIMS) has proven to be a powerful method for isotope selective ultra-trace analysis of long-lived radioisotopes. For plutonium detection limits of 106 to 107 atoms have been achieved for various types of samples. So far a three-step, three-color laser excitation scheme was applied for efficient ionization. In this work, a two-photon transition from an excited state into a high-lying autoionizing state, will be presented, yielding a similar overall efficiency as the three-step, three-color ionization scheme. In this way, only two tunable lasers are needed, while the advantages of a three-step, three-color excitation (high selectivity, good efficiency and low non-resonant background) are preserved. The two-photon transition has been characterized with respect to saturation behavior and line width. The three-step, two-color ionization is a possibility for an improved RIMS procedure.

  6. Passive synchronization between a self-similar pulse and a bound-soliton bunch in a two-color mode-locked fiber laser.

    PubMed

    Hsiang, Wei-Wei; Chang, Chia-Hao; Cheng, Chien-Po; Lai, Yinchieh

    2009-07-01

    We report the first (to our knowledge) experimental observation of passive synchronization between a 1.03 microm self-similar pulse and a 1.56 microm bound-soliton bunch in a two-color mode-locked fiber laser. The self-similar pulse can form an effective potential well of several picoseconds to trap the copropagating bound solitons in the shared-fiber section. Such synchronization mechanism is supported by the experimental evidence of smaller time separation between the bound solitons under synchronization. In addition, the self-similar pulse and bound solitons can still remain locked under the periodic collision of another 1.56 microm unlocked pulse train. PMID:19571968

  7. High-lying bound Rydberg states of excited Hg(6s6p {sup 3}P{sub 1}) atoms from two-color resonance ionization mass spectroscopy

    SciTech Connect

    Bisling, Peter; Dederichs, Jan; Neidhart, Bernd; Weitkamp, Claus

    1998-12-16

    Mercury isotopes are investigated with two-color resonance ionization mass spectroscopy (RIMS). Isotope shifts, hyperfine structure splittings, and the lifetime of the intermediate 6s6p {sup 3}P{sub 1} state are determined by RIMS. Ion yields at the threshold region in various static electric fields are measured in order to determine an extrapolated ionization energy value at zero field strength. New energy values for high-lying bound 6s nd {sup 3}D (21

  8. Optimal control of high-order harmonics for the generation of an isolated ultrashort attosecond pulse with two-color midinfrared laser fields

    NASA Astrophysics Data System (ADS)

    Chou, Yi; Li, Peng-Cheng; Ho, Tak-San; Chu, Shih-I.

    2015-06-01

    We present an efficient high-order-harmonic optimal control scheme for the generation of the ultrabroad supercontinuum spectrum and an isolated ultrashort attosecond pulse in gases with a two-color mid-IR laser field. The optimal control scheme is implemented using a derivative-free unconstrained optimization algorithm called NEWUOA (NEW Unconstrained Optimization Algorithm). For illustration, the high-order-harmonic generation (HHG) of a hydrogen atom is considered for optimization. It is shown that optimally shaped laser waveforms can greatly enhance and extend the HHG plateau and efficiently generate an isolated ultrashort attosecond pulse. Moreover, by performing accurate semiclassical simulations and a detailed wavelet time-frequency analysis, we found that the optimized supercontinuum harmonics corresponding to long-trajectory electrons are responsible for an isolated ultrashort 21-as pulse.

  9. Two-color spectroscopy of UV excited ssDNA complex with a single-wall nanotube (SWNT) probe: Fast nucleobase autoionization mechanism

    NASA Astrophysics Data System (ADS)

    Rotkin, Slava V.; Ignatova, Tetyana; Balaeff, Alexander; Zheng, Ming; Blades, Michael; Stoeckl, Peter

    DNA autoionization is a fundamental process wherein UV-photoexcited nucleobases dissipate energy to the environment without undergoing chemical damage. SWNT is shown to serve as a photoluminescent reporter for studying the mechanism and rates of DNA autoionization. Two-color photoluminescence (PL) spectroscopy revealed a strong SWNT PL quenching when the UV pump is resonant with the DNA absorption [Nano Research, 2015]. Semiempirical calculations of the DNA-SWNT electronic structure, combined with a Green's function theory for charge transfer, show a 20 fs autoionization rate, dominated by the hole transfer. Rate-equation analysis of the spectroscopy data confirms that the quenching rate is limited by the thermalization of the free charge carriers transferred to the nanotube reservoir. The developed approach has a great potential for monitoring DNA excitation, autoionization, and chemical damage both in vivo and in vitro. NSF ECCS-1509786 (S.V.R.,T.I.) and PHY-1359195 (P.S.), NIST and UCF facilities.

  10. Generation of Bright, Spatially Coherent Soft X-Ray High Harmonics in a Hollow Waveguide Using Two-Color Synthesized Laser Pulses

    NASA Astrophysics Data System (ADS)

    Jin, Cheng; Stein, Gregory J.; Hong, Kyung-Han; Lin, C. D.

    2015-07-01

    We investigate the efficient generation of low-divergence high-order harmonics driven by waveform-optimized laser pulses in a gas-filled hollow waveguide. The drive waveform is obtained by synthesizing two-color laser pulses, optimized such that highest harmonic yields are emitted from each atom. Optimization of the gas pressure and waveguide configuration has enabled us to produce bright and spatially coherent harmonics extending from the extreme ultraviolet to soft x rays. Our study on the interplay among waveguide mode, atomic dispersion, and plasma effect uncovers how dynamic phase matching is accomplished and how an optimized waveform is maintained when optimal waveguide parameters (radius and length) and gas pressure are identified. Our analysis should help laboratory development in the generation of high-flux bright coherent soft x rays as tabletop light sources for applications.

  11. Energetic ion observations in the magnetic cloud of 14-15 January 1988 and their implications for the magnetic field topology

    NASA Technical Reports Server (NTRS)

    Richardson, I. G.; Farrugia, C. J.; Burlaga, L. F.

    1991-01-01

    On 14-15 January 1988, a magnetic cloud with a local field topology consistent with an east-west aligned cylindrical flux-rope and which formed the driver of an interplanetary shock passed the earth. Using 0.5-4 MeV/n ion data from the instrument on IMP 8, the paper addresses the question of whether or not magnetic field lines within the magnetic cloud were connected to the sun. An impulsive solar particle event was detected inside the magnetic cloud strongly suggesting that the field lines were rooted at the sun.

  12. Study of the 20,22Ne+20,22Ne and 10,12,13,14,15C+12C Fusion Reactions with MUSIC

    NASA Astrophysics Data System (ADS)

    Avila, M. L.; Rehm, K. E.; Almaraz-Calderon, S.; Carnelli, P. F. F.; DiGiovine, B.; Esbensen, H.; Hoffman, C. R.; Jiang, C. L.; Kay, B. P.; Lai, J.; Nusair, O.; Pardo, R. C.; Santiago-Gonzalez, D.; Talwar, R.; Ugalde, C.

    2016-05-01

    A highly efficient MUlti-Sampling Ionization Chamber (MUSIC) detector has been developed for measurements of fusion reactions. A study of fusion cross sections in the 10,12,13,14,15C+12C and 20,22Ne+20,22Ne systems has been performed at ATLAS. Experimental results and comparison with theoretical predictions are presented. Furthermore, results of direct measurements of the 17O(α, n)20Ne, 23Ne(α, p)26Mg and 23Ne(α, n)26Al reactions will be discussed.

  13. Two-color SERS microscopy for protein co-localization in prostate tissue with primary antibody-protein A/G-gold nanocluster conjugates

    NASA Astrophysics Data System (ADS)

    Salehi, Mohammad; Schneider, Lilli; Ströbel, Philipp; Marx, Alexander; Packeisen, Jens; Schlücker, Sebastian

    2014-01-01

    SERS microscopy is a novel staining technique in immunohistochemistry, which is based on antibodies labeled with functionalized noble metal colloids called SERS labels or nanotags for optical detection. Conventional covalent bioconjugation of these SERS labels cannot prevent blocking of the antigen recognition sites of the antibody. We present a rational chemical design for SERS label-antibody conjugates which addresses this issue. Highly sensitive, silica-coated gold nanoparticle clusters as SERS labels are non-covalently conjugated to primary antibodies by using the chimeric protein A/G, which selectively recognizes the Fc part of antibodies and therefore prevents blocking of the antigen recognition sites. In proof-of-concept two-color imaging experiments for the co-localization of p63 and PSA on non-neoplastic prostate tissue FFPE specimens, we demonstrate the specificity and signal brightness of these rationally designed primary antibody-protein A/G-gold nanocluster conjugates.SERS microscopy is a novel staining technique in immunohistochemistry, which is based on antibodies labeled with functionalized noble metal colloids called SERS labels or nanotags for optical detection. Conventional covalent bioconjugation of these SERS labels cannot prevent blocking of the antigen recognition sites of the antibody. We present a rational chemical design for SERS label-antibody conjugates which addresses this issue. Highly sensitive, silica-coated gold nanoparticle clusters as SERS labels are non-covalently conjugated to primary antibodies by using the chimeric protein A/G, which selectively recognizes the Fc part of antibodies and therefore prevents blocking of the antigen recognition sites. In proof-of-concept two-color imaging experiments for the co-localization of p63 and PSA on non-neoplastic prostate tissue FFPE specimens, we demonstrate the specificity and signal brightness of these rationally designed primary antibody-protein A/G-gold nanocluster conjugates

  14. New MBE buffer for micron- and quarter-micron-gateGaAs MESFETs

    NASA Technical Reports Server (NTRS)

    1988-01-01

    A new buffer layer has been developed that eliminates backgating in GaAs MESFETs and substantially reduces short-channel effects in GaAs MESFETs with 0.27-micron-long gates. The new buffer is grown by molecular beam epitaxy (MBE) at a substrate temperature of 200 C using Ga and As sub 4 beam fluxes. The buffer is crystalline, highly resistive, optically inactive, and can be overgrown with high quality GaAs. GaAs MESFETs with a gate length of 0.27 microns that incorporate the new buffer show improved dc and RF properties in comparison with a similar MESFET with a thin undoped GaAs buffer. To demonstrate the backgating performance improvement afforded by the new buffer, MESFETs were fabricated using a number of different buffer layers and structures. A schematic cross section of the MESFET structure used in this study is shown. The measured gate length, gate width, and source-drain spacing of this device are 2,98, and 5.5 microns, respectively. An ohmic contact, isolated from the MESFET by mesa etching, served as the sidegate. The MESFETs were fabricated in MBE n-GaAs layers grown on the new buffer and also in MBE n-GaAs layers grown on buffer layers of undoped GaAs, AlGaAs, and GaAs/AlGaAs superlattices. All the buffer layers were grown by MBE and are 2 microns thick. The active layer is doped to approximately 2 x 10 to the 17th/cu cm with silicon and is 0.3 microns thick.

  15. The Earth’s magnetosphere response to interplanetary medium conditions on January 21-22, 2005 and on December 14-15, 2006

    NASA Astrophysics Data System (ADS)

    Kalegaev, V. V.; Vlasova, N. A.

    2014-08-01

    The Earth’s magnetosphere response to interplanetary medium conditions on January 21-22, 2005 and on December 14-15, 2006 has been studied. The analysis of solar wind parameters measured by ACE spacecraft, of geomagnetic indices variations, of geomagnetic field measured by GOES 11, 12 satellites, and of energetic particle fluxes measured by POES 15, 16, 17 satellites was performed together with magnetospheric modeling based in terms of A2000 paraboloid model. We found the similar dynamics of three particle populations (trapped, quasi-trapped, and precipitating) during storms of different intensities developed under different external conditions: the maximal values of particle fluxes and the latitudinal positions of the isotropic boundaries were approximately the same. The main sources caused RC build-up have been determined for both magnetic storms. Global magnetospheric convection controlled by IMF and substorm activity driven magnetic storm on December 14-15, 2006. Extreme solar wind pressure pulse was mainly responsible for RC particle injection and unusual January 21, 2005 magnetic storm development under northward IMF during the main phase.

  16. 3 micron spectrophotometry of Comet Halley - Evidence for water ice

    NASA Technical Reports Server (NTRS)

    Bregman, Jesse D.; Tielens, A. G. G. M.; Witteborn, Fred C.; Rank, David M.; Wooden, Diane

    1988-01-01

    Structure has been observed in the 3-3.6 micron preperihelion spectrum of Comet Halley consistent with either an absorption band near 3.1 microns or emission near 3.3 microns. The results suggest that a large fraction of the water molecules lost by the comet are initially ejected in the form of small ice particles rather than in the gas phase.

  17. Near 16 micron CO.sub.2 laser system

    DOEpatents

    Krupke, William F.

    1977-01-01

    Method and apparatus for inducing laser action in CO.sub.2 at a wavelength of 16 microns involving the transition between the 02.sup.0 0 and 01.sup.1 0 states. The population inversion between these two states is achieved by pumping to the 00.sup.0 1 level, suppressing the usual 10.6 micron transition to the 10.sup.0 0 level and encouraging the 9.6 micron transition, thereby populating the 02.sup.0 0 level, as the principal prerequisite for 16 micron laser action between the 02.sup.0 0 and 01.sup.1 0 levels.

  18. Roles of the 2 microns gene products in stable maintenance of the 2 microns plasmid of Saccharomyces cerevisiae.

    PubMed Central

    Reynolds, A E; Murray, A W; Szostak, J W

    1987-01-01

    We have examined the replication and segregation of the Saccharomyces cerevisiae 2 microns circle. The amplification of the plasmid at low copy numbers requires site-specific recombination between the 2 microns inverted repeat sequences catalyzed by the plasmid-encoded FLP gene. No other 2 microns gene products are required. The overexpression of FLP in a strain carrying endogenous 2 microns leads to uncontrolled plasmid replication, longer cell cycles, and cell death. Two different assays show that the level of Flp activity decreases with increasing 2 microns copy number. This regulation requires the products of the REP1 and REP2 genes. These gene products also act together to ensure that 2 microns molecules are randomly segregated between mother and daughter cells at cell division. Images PMID:3316982

  19. Full-band structure calculations of optical injection in semiconductors: Investigations of one-color, two-color, and pump-probe scenarios

    NASA Astrophysics Data System (ADS)

    Robinson, Michael

    Carrier, spin, charge current, and spin current injection by one- and two-color optical schemes are investigated within 30-band k ˙ p theory. Parameters of the band model are optimized to give full-Brillouin zone band structures for GaAs and Ge that give accurate Gamma-point effective masses and gyromagnetic factors and give access to the L valley, and to the E1 and E1 + Delta1 critical points in the linear optical absorption. Calculations of one- and two-photon carrier and spin injection and two-color current injection are performed for excitation energies in the range of 0--4 eV in GaAs and 0--3.5 eV in Ge. Significant spin and spin current injection occurs with 30% spin polarization in GaAs and Ge at photon energy matching the E1 critical point. Further, the anisotropy and disparity of the current injection between parallel and perpendicular linearly-polarized beam configurations are calculated. For light propagating along a <111> crystal axis, anisotropic contributions in coherent current control and two-photon spin injection give rise to normal current components and in-plane spin components. In Ge, contributions from the holes to spin, electrical current, and spin current injection are investigated. Optical orientation results in 83% spin-polarized holes at the band edge. The effects of carrier dynamics in Ge are treated within a rate-equation model. The detection of spin dynamics in a pump-probe setup is considered, and the Fermi-factor approach is justified for electrons but not for holes. Carrier and current injection are further investigated in single-layer and bilayer graphene within the tight-binding model. In single-layer graphene, the linear-circular dichroism in two-photon absorption yields an absorption coefficient that is twice as large for circularly polarized light compared to linearly polarized light. Coherent current injection is largest for co-circularly polarized beams and zero for cross-circularly polarized beams. For linearly polarized

  20. NMR Microscopy - Micron-Level Resolution.

    NASA Astrophysics Data System (ADS)

    Kwok, Wing-Chi Edmund

    1990-01-01

    Nuclear Magnetic Resonance Imaging (MRI) has been developed into a powerful and widely used diagnostic tool since the invention of techniques using linear magnetic field gradients in 1973. The variety of imaging contrasts obtainable in MRI, such as spin density, relaxation times and flow rate, gives MRI a significant advantage over other imaging techniques. For common diagnostic applications, image resolutions have been in the order of millimeters with slice thicknesses in centimeters. For many research applications, however, resolutions in the order of tens of microns or smaller are needed. NMR Imaging in these high resolution disciplines is known as NMR microscopy. Compared with conventional microscopy, NMR microscopy has the advantage of being non-invasive and non-destructive. The major obstacles of NMR microscopy are low signal-to-noise ratio and effects due to spin diffusion. To overcome these difficulties, more sensitive RF probes and very high magnetic field gradients have to be used. The most effective way to increase sensitivity is to build smaller probes. Microscope probes of different designs have been built and evaluated. Magnetic field gradient coils that can produce linear field gradients up to 450 Gauss/cm were also assembled. In addition, since microscope probes often employ remote capacitors for RF tuning, the associated signal loss in the transmission line was studied. Imaging experiments have been carried out in a 2.1 Tesla small bore superconducting magnet using the typical two-dimensional spin warp imaging technique. Images have been acquired for both biological and non-biological samples. The highest resolution was obtained in an image of a nerve bundle from the spinal cord of a racoon and has an in-plane resolution of 4 microns. These experiments have demonstrated the potential application of NMR microscopy to pathological research, nervous system study and non -destructive testings of materials. One way to further improve NMR microscopy is

  1. Deformation Behavior of Sub-micron and Micron Sized Alumina Particles in Compression.

    SciTech Connect

    Sarobol, Pylin; Chandross, Michael E.; Carroll, Jay; Mook, William; Boyce, Brad; Kotula, Paul G.; McKenzie, Bonnie B.; Bufford, Daniel Charles; Hall, Aaron Christopher.

    2014-09-01

    The ability to integrate ceramics with other materials has been limited due to high temperature (>800degC) ceramic processing. Recently, researchers demonstrated a novel process , aerosol deposition (AD), to fabricate ceramic films at room temperature (RT). In this process, sub - micro n sized ceramic particles are accelerated by pressurized gas, impacted on the substrate, plastically deformed, and form a dense film under vacuum. This AD process eliminates high temperature processing thereby enabling new coatings and device integration, in which ceramics can be deposited on metals, plastics, and glass. However, k nowledge in fundamental mechanisms for ceramic particle s to deform and form a dense ceramic film is still needed and is essential in advancing this novel RT technology. In this wo rk, a combination of experimentation and atomistic simulation was used to determine the deformation behavior of sub - micron sized ceramic particle s ; this is the first fundamental step needed to explain coating formation in the AD process . High purity, singl e crystal, alpha alumina particles with nominal size s of 0.3 um and 3.0 um were examined. Particle characterization, using transmission electron microscopy (TEM ), showed that the 0.3 u m particles were relatively defect - free single crystals whereas 3.0 u m p articles were highly defective single crystals or particles contained low angle grain boundaries. Sub - micron sized Al 2 O 3 particles exhibited ductile failure in compression. In situ compression experiments showed 0.3um particles deformed plastically, fractured, and became polycrystalline. Moreover, dislocation activit y was observed within the se particles during compression . These sub - micron sized Al 2 O 3 particles exhibited large accum ulated strain (2 - 3 times those of micron - sized particles) before first fracture. I n agreement with the findings from experimentation , a tomistic simulation s of nano - Al 2 O 3 particles showed dislocation slip and

  2. Investigation of the pairing effect using newly evaluated empirical studies for 14-15 MeV neutron reaction cross sections

    SciTech Connect

    Tel, E.; Tanir, G.; Aydin, A.

    2007-03-15

    The asymmetry term effects for the cross sections of (n, charged particle) and (n,2n) reactions at 14-15 MeV neutron incident energy have been investigated. The effects of pairing and odd-even nucleon numbers in new data and in the formula of Tel et al. [J. Phys. G. 29, 2169 (2003)] are discussed. We have determined three different parameters groups by the classification of nuclei into even-even, even-odd, and odd-even (n,d) reactions. In addition, since there are not enough experimental data available, we have considered two different parameters groups by the classification of nuclei into odd-A and even-A (n,t) reaction cross sections. The empirical formulas with two parameters for the evaluation of the (n,d) and (n,t) reactions cross sections are discussed in the present study.

  3. Tuberculin Skin Test Negativity Is Under Tight Genetic Control of Chromosomal Region 11p14-15 in Settings With Different Tuberculosis Endemicities

    PubMed Central

    Cobat, Aurélie; Poirier, Christine; Hoal, Eileen; Boland-Auge, Anne; de La Rocque, France; Corrard, François; Grange, Ghislain; Migaud, Mélanie; Bustamante, Jacinta; Boisson-Dupuis, Stéphanie; Casanova, Jean-Laurent; Schurr, Erwin; Alcaïs, Alexandre; Delacourt, Christophe; Abel, Laurent

    2015-01-01

    A substantial proportion of subjects exposed to a contagious tuberculosis case display lack of tuberculin skin test (TST) reactivity. We previously mapped a major locus (TST1) controlling lack of TST reactivity in families from an area in South Africa where tuberculosis is hyperendemic. Here, we conducted a household tuberculosis contact study in a French area where the endemicity of tuberculosis is low. A genome-wide analysis of TST negativity identified a significant linkage signal (P < 3 × 10−5) in close vicinity of TST1. Combined analysis of the 2 samples increased evidence of linkage (P = 2.4 × 10−6), further implicating genetic factors located on 11p14-15. This region overlaps the TNF1 locus controlling mycobacteria-driven tumor necrosis factor α production. PMID:25143445

  4. Highly selective two-color mid-wave and long-wave infrared detector hybrid based on Type-II superlattices.

    PubMed

    Huang, Edward Kwei-wei; Hoang, Minh-Anh; Chen, Guanxi; Ramezani-Darvish, Shaban; Haddadi, Abbas; Razeghi, Manijeh

    2012-11-15

    We report a two-color mid-wave infrared (MWIR) and long-wave infrared (LWIR) co-located detector with 3 μm active region thickness per channel that is highly selective and can perform under high operating temperatures for the MWIR band. Under back-side illumination, a temperature evolution study of the MWIR detector's electro-optical performance found the 300 K background-limit with 2π field-of-view to be achieved below operating temperatures of 160 K, at which the temperature's 50% cutoff wavelength was 5.2 μm. The measured current reached the system limit of 0.1 pA at 110 K for 30 μm pixel-sized diodes. At 77 K, where the LWIR channel operated with a 50% cutoff wavelength at 11.2 μm, an LWIR selectivity of ~17% was achieved in the MWIR wave band between 3 and 4.7 μm, making the detector highly selective. PMID:23164899

  5. Overcritical plasma ignition and diagnostics from oncoming interaction of two color low energy tightly focused femtosecond laser pulses inside fused silica

    NASA Astrophysics Data System (ADS)

    Potemkin, F. V.; Bravy, B. G.; Bezsudnova, Yu I.; Mareev, E. I.; Starostin, V. M.; Platonenko, V. T.; Gordienko, V. M.

    2016-04-01

    We report overcritical (3.3  ×  1021 cm-3) microplasma produced by low energy colliding IR (infrared) (1.24 μm) and visible (0.62 μm) femtosecond pulses tightly focused (NA  =  0.5) into the bulk of fused silica with on-line monitoring based on third harmonic generated by the IR beam. It was established that the absorbed energy density is the key parameter that determines the micromodification formation threshold and in our experimental conditions it is close to 4.5 kJ cm-3. Non-monotonic behavior of the third harmonic signal as a function of time delay between visible (0.62 μm) and IR (1.24 μm) femtosecond pulses demonstrates the qualitative differences about the two phenomena: one is the seed electrons generation by the visible pulse via multiphoton ionization and second is the avalanche ionization by the IR pulse. We predict that the tandem two-color excitation of wide-bandgap dielectric in comparison with single-color pulse interaction regime allows providing a much higher absorbed energy density and overcritical plasma.

  6. Unraveling the rat blood genome-wide transcriptome after oral administration of lavender oil by a two-color dye-swap DNA microarray approach.

    PubMed

    Hori, Motohide; Kubo, Hiroko; Shibato, Junko; Saito, Tomomi; Ogawa, Tetsuo; Wakamori, Minoru; Masuo, Yoshinori; Shioda, Seiji; Rakwal, Randeep

    2016-06-01

    Lavender oil (LO) is a commonly used essential oil in aromatherapy as non-traditional medicine. With an aim to demonstrate LO effects on the body, we have recently established an animal model investigating the influence of orally administered LO in rat tissues, genome-wide. In this brief, we investigate the effect of LO ingestion in the blood of rat. Rats were administered LO at usual therapeutic dose (5 mg/kg) in humans, and following collection of the venous blood from the heart and extraction of total RNA, the differentially expressed genes were screened using a 4 × 44-K whole-genome rat chip (Agilent microarray platform; Agilent Technologies, Palo Alto, CA, USA) in conjunction with a two-color dye-swap approach. A total of 834 differentially expressed genes in the blood were identified: 362 up-regulated and 472 down-regulated. These genes were functionally categorized using bioinformatics tools. The gene expression inventory of rat blood transcriptome under LO, a first report, has been deposited into the Gene Expression Omnibus (GEO): GSE67499. The data will be a valuable resource in examining the effects of natural products, and which could also serve as a human model for further functional analysis and investigation. PMID:27330992

  7. One-electron oxidation of alcohols by the 1,3,5-trimethoxybenzene radical cation in the excited state during two-color two-laser flash photolysis.

    PubMed

    Cai, Xichen; Sakamoto, Masanori; Fujitsuka, Mamoru; Majima, Tetsuro

    2007-03-15

    One-electron oxidation of alcohols such as methanol, ethanol, and 2-propanol by 1,3,5-trimethoxybenzene radical cation (TMB*+) in the excited state (TMB*+*) was observed during the two-color two-laser flash photolysis. TMB*+ was formed by the photoinduced bimolecular electron-transfer reaction from TMB to 2,3,5,6-tetrachlorobenzoquinone (TCQ) in the triplet excited-state during the first 355-nm laser flash photolysis. Then, TMB*+* was generated from the selective excitation of TMB*+ during the second 532 nm laser flash photolysis. Hole transfer rate constants from TMB*+* to methanol, ethanol, and 2-propanol were calculated to be (5.2 +/- 0.5) x 10(10), (1.4 +/- 0.3) x 10(11), and (3.2 +/- 0.6) x 10(11) M-1 s-1, respectively. The order of the hole transfer rate constants is consistent with oxidation potentials of alcohol. Formation of TCQH radical (TCQH*) with a characteristic absorption peak at 435 nm was observed in the microsecond time scale, suggesting that deprotonation of the alcohol radical cation occurs after the hole transfer and that TCQ radical anion (TCQ*-), generated together with TMB*+ by the photoinduced electron-transfer reaction, reacts with H+ to give TCQH*. PMID:17295459

  8. Two-color experiments combining the UV storage ring free-electron laser and the SA5 IR beamline at Super-ACO

    NASA Astrophysics Data System (ADS)

    Nahon, Laurent; Renault, Eric; Couprie, Marie-Emmanuelle; Nutarelli, Daniele; Garzella, David; Billardon, Michel; Carr, G. Lawrence; Williams, Gwyn P.; Dumas, Paul

    1999-10-01

    The UV-storage ring Free Electron Laser (FEL) operating at Super-ACO is a tunable, coherent and intense (up to 300 mW) photon source in the near-UV range (300 - 350 nm). Besides, it has the unique feature to be synchronized in a one-to-one shot ratio with the Synchrotron Radiation (SR) at the high repetition rate of 8.32 MHz. This FEL + SR combination appears to be very powerful for the performance of pump- probe time-resolved and/or frequency-resolved experiments on the sub-ns and ns time-scales. In particular, there is a strong scientific case for the combination of the recently- commissioned SA5 Infra-Red Synchrotron Radiation beamline with the UV-FEL, for the performance of transient IR- absorption spectroscopy on FEL-excited samples with a Fourier-transform spectrometer coupled with a microscope allowing high spectral and spatial resolution. The principle and interest of the two-color combination altogether with the description of both the FEL and the SA5 IR beamline are presented. The first synchronization signal between the IR and the UV beams is shown. The correct spatial overlap between the UV (FEL) and the IR (SR) photon beams is demonstrated by monitoring via IR-spectro-microscopy the time evolution of a single mineral particulate (kaolinite) under UV-FEL irradiation.

  9. Design and initial operation of a two-color soft x-ray camera system on the Compact Toroidal Hybrid experiment

    SciTech Connect

    Herfindal, J. L. Dawson, J. D.; Ennis, D. A.; Hartwell, G. J.; Loch, S. D.; Maurer, D. A.

    2014-11-15

    A multi-camera soft x-ray diagnostic has been developed to measure the equilibrium electron temperature profile and temperature fluctuations due to magnetohydrodynamic activity on the Compact Toroidal Hybrid experiment. The diagnostic consists of three separate cameras each employing two 20-channel diode arrays that view the same plasma region through different beryllium filter thicknesses of 1.8 μm and 3.0 μm allowing electron temperature measurements between 50 eV and 200 eV. The Compact Toroidal Hybrid is a five-field period current-carrying stellarator, in which the presence of plasma current strongly modifies the rotational transform and degree of asymmetry of the equilibrium. Details of the soft x-ray emission, effects of plasma asymmetry, and impurity line radiation on the design and measurement of the two-color diagnostic are discussed. Preliminary estimates of the temperature perturbation due to sawtooth oscillations observed in these hybrid discharges are given.

  10. The mechanics of unrest at Long Valley caldera, California: 1. Modeling the geometry of the source using GPS, leveling and two-color EDM data

    USGS Publications Warehouse

    Battaglia, Maurizio; Segall, P.; Murray, J.; Cervelli, Peter; Langbein, J.

    2003-01-01

    We surveyed 44 existing leveling monuments in Long Valley caldera in July 1999, using dual frequency global positioning system (GPS) receivers. We have been able to tie GPS and leveling to a common reference frame in the Long Valley area and computed the vertical deformation by differencing GPS-based and leveled orthometric heights. The resurgent dome uplifted 74??7 cm from 1975 to 1999. To define the inflation source, we invert two-color EDM and uplift data from the 1985-1999 unrest period using spherical or ellipsoidal sources. We find that the ellipsoidal source satisfies both the vertical and horizontal deformation data, whereas the spherical point source cannot. According to our analysis of the 1985-1999 data, the main source of deformation is a prolate ellipsoid located beneath the resurgent dome at a depth of 5.9 km (95% bounds of 4.9-7.5 km). This body is vertically elongated, has an aspect ratio of 0.475 (95% bounds are 0.25-0.65) and a volume change of 0.086 km3 (95% bounds are 0.06-0.13 km3). Failure to account for the ellipsoidal nature of the source biases the estimated source depth by 2.1 km (35%), and the source volume by 0.038 km3 (44%). ?? 2003 Elsevier B.V. All rights reserved.

  11. Numerical Simulation of Spatial and Spectral Crosstalk in Two-Color MWIR/LWIR HgCdTe Infrared Detector Arrays

    NASA Astrophysics Data System (ADS)

    Pinkie, Benjamin; Bellotti, Enrico

    2013-11-01

    The sequential two-color Hg1- x Cd x Te architecture has emerged as a key technology in the development of third-generation infrared detectors. Due to the expense required to manufacture these devices, it is imperative to create numerical models which can predict the electrical and optical behavior of the technology as well as evaluate design concepts prior to exhaustive development. We have developed a three-dimensional simulation model which fully accounts for the optical phenomena that become increasingly important in small pixels and uses a drift-diffusion approach to determine the electrical behavior of the device. In particular, we employ a finite-difference time- domain method to solve Maxwell's equations and a finite-element method to evaluate the solutions of the coupled Poisson and carrier continuity equations. We apply our simulation model to simulate the dynamic resistance and current density versus voltage characteristics of this detector architecture. The quantum efficiency is then determined for both spectral bands while observing the effects of variable pixel pitch and detector geometry. Finally, we use a spatially finite Gaussian beam to analyze the crosstalk and perform a simulated spot scan.

  12. Extinction and scattering by several types of silicate sphere of radius 0.05-1.0 micron, for the wavelength range 0.21-50 microns.

    NASA Technical Reports Server (NTRS)

    Bromage, G. E.; Nandy, K.; Khare, B. N.

    1973-01-01

    The exact calculation of scattering and absorption by various sub-micron sized silicate spheres is presented here, using accurately determined optical constants in the wavelength range from 50 to 0.21 microns. The extinction features near 10 and 20 microns for various samples are discussed. It is found that the ratio of peak extinction at 20 microns to that at 10 microns is constant for small particles up to 0.4-micron radius, but is less for particles of 1-micron radius. The ratio of maximum extinction in the ultraviolet to that at 10 microns decreases with increasing particle size.

  13. A new fast two-color interferometer at Alcator C-Mod for turbulence measurements and comparison with phase contrast imaging

    SciTech Connect

    Kasten, C. P. White, A. E.; Irby, J. H.

    2014-04-15

    Accurately predicting the turbulent transport properties of magnetically confined plasmas is a major challenge of fusion energy research. Validation of transport models is typically done by applying so-called “synthetic diagnostics” to the output of nonlinear gyrokinetic simulations, and the results are compared to experimental data. As part of the validation process, comparing two independent turbulence measurements to each other provides the opportunity to test the synthetic diagnostics themselves; a step which is rarely possible due to limited availability of redundant fluctuation measurements on magnetic confinement experiments. At Alcator C-Mod, phase-contrast imaging (PCI) is a commonly used turbulence diagnostic. PCI measures line-integrated electron density fluctuations with high sensitivity and wavenumber resolution (1.6 cm{sup −1}≲|k{sub R}|≲11 cm{sup −1}). A new fast two-color interferometry (FTCI) diagnostic on the Alcator C-Mod tokamak measures long-wavelength (|k{sub R}|≲3.0 cm{sup −1}) line-integrated electron density fluctuations. Measurements of coherent and broadband fluctuations made by PCI and FTCI are compared here for the first time. Good quantitative agreement is found between the two measurements. This provides experimental validation of the low-wavenumber region of the PCI calibration, and also helps validate the low-wavenumber portions of the synthetic PCI diagnostic that has been used in gyrokinetic model validation work in the past. We discuss possibilities to upgrade FTCI, so that a similar comparison could be done at higher wavenumbers in the future.

  14. A high resolution atlas of the galactic plane at 12 microns and 25 microns

    NASA Technical Reports Server (NTRS)

    Price, Stephan D.; Korte, Rose M.; Sample, Rebecca S.; Kennealy, John P.; Gonsalves, Robert A.

    1994-01-01

    High resolution images of the 12 micron and 25 micron IRAS survey data from each HCON crossing the Galactic Plane are being created for those regions that the original IRAS processing labeled as confused. This encompasses the area within 100 deg longitude of the Galactic Center and within 3 deg to 10 deg of the Plane. The procedures used to create the images preserve the spatial resolution inherent in the IRAS instrument. The images are separated into diffuse and point source components and candidate sources are extracted from the point source image after non-linear spatial sharpening. Fluxes are estimated by convolving the candidate sources with the point response function and cross-correlating with the original point source image. A source is considered real if it is seen on at least two HCON's with a rather generous flux match but a stringent position criterion. A number of fields spanning a range of source densities from low to high have been examined. Initial analysis indicates that the imaging and extraction works quite well up to a source density of about 100 sources per square degree or down to roughly 0.8 Janskys.

  15. Substitution of Micron by Nanometer Scale Powders in Magnetorheological Fluids

    NASA Astrophysics Data System (ADS)

    Chaudhuri, A.; Wang, G.; Wereley, N. M.; Tasovksi, Vasil; Radhakrishnan, R.

    The effects of substitution of micron size powder by nanometer size powder in magnetorheological (MR) fluids are investigated in this study. Three MR fluid samples containing iron powder with 45% weight fraction in a carrier fluid were made by Materials Modification Inc. The difference among these three fluids is size of the magnetic particles. The first MR fluid sample contained only micron size iron powder with 10μm particle size. In the second sample, 5% micron iron was substituted with nano powders having 30~40nm mean diameter, while the third sample had 37.5% micron powder and 7.5% nano powder. Rheological tests were conducted on the three samples using a parallel disk rheometer. Highest yield stress was observed in the second MR fluid sample containing 40% micron and 5% nano iron powder. By replacing only 5% micron iron powder with nanoparticles, we achieved substantial increment in yield stress. However, when nano powder content is increased to 7.5%, the yield stress decreases and is lower than that in the all micron MR fluid. Thus, by doping a reasonable percent of nano iron powder in the MR fluid, a substantial change in the rheological characteristics is obtainable. Further investigations of effects of nano iron powder in MR fluids for higher weight fraction MR fluids will be carried out in future.

  16. Three-micron spectroscopy of highly reddened field stars

    NASA Technical Reports Server (NTRS)

    Tapia, Mauricio; Persi, P.; Roth, M.; Ferrari-Toniolo, M.

    1989-01-01

    Broad absorption features centered at 3.45 microns and at 3.0-3.0 microns towards a number of late-type supergiants in the vicinity of the galactic center were repeatedly reported. Here, 2.0 to 2.5 and 3.0 to 4.0 micron spectra are presented for field late-type highly reddened (A sub V is approximately 17-27) stars located in different regions of the galactic plane more than 20 deg away from the galactic center direction. The observations, made with the 3.6, 2.2, and 1.0 m ESO telescopes at La Silla, Chile, consists of CVF spectra with resolution lambda/delta lambda is approximately or equal to 100 and IRSPEC spectra with resolution lambda/delta lambda is approximately or equal to 700. In the direction of the most highly reddened stars, definitive detections of the 3.45 and the 3.0 to 3.1 micron absorption features are reported. The 3.45 micron feature was attributed to absorption arising in a vibrational transition resulting from the C-H stretching in organic compounds, while the 3.0 to 3.1 micron broader feature are tentatively attributed to O-H bonds. The observations strongly support that the agent producing the 3.45 micron feature, presumably organic molecules, is an important component of the diffuse interstellar medium and is not characteristic only of the galactic center environment.

  17. New Evaluated Semi-Empirical Formula Using Optical Model for 14-15 MeV ( n, t) Reaction Cross Sections

    NASA Astrophysics Data System (ADS)

    Tel, E.; Durgu, C.; Aydın, A.; Bölükdemir, M. H.; Kaplan, A.; Okuducu, Ş.

    2009-12-01

    In the next century the world will face the need for new energy sources. Nuclear fusion can be one of the most attractive sources of energy from the viewpoint of safety and minimal environmental impact. Fusion will not produce CO2 or SO2 and thus will not contribute to global warming or acid rain. Achieving acceptable performance for a fusion power system in the areas of economics, safety and environmental acceptability, is critically dependent on performance of the blanket and diverter systems which are the primary heat recovery, plasma purification, and tritium breeding systems. Tritium self-sufficiency must be maintained for a commercial power plant. The hybrid reactor is a combination of the fusion and fission processes. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. So working out the systematics of ( n, t) reaction cross-sections are of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at energies up to 20 MeV. In this study, we have calculated non-elastic cross-sections by using optical model for ( n, t) reactions at 14-15 MeV energy. We have investigated the excitation function character and reaction Q-values depending on the asymmetry term effect for the ( n, t) reaction cross-sections. We have obtained new coefficients for the ( n, t) reaction cross-sections. We have suggested semi-empirical formulas including optical model nonelastic effects by fitting two parameters for the ( n, t) reaction cross-sections at 14-15 MeV. We have discussed the odd-even effect and the pairing effect considering binding energy systematic of the nuclear shell model for the new experimental data and new cross-sections formulas ( n, t) reactions developed by Tel et al. We have determined a different parameter groups by the classification of nuclei into even-even, even-odd and odd-even for ( n, t) reactions cross-sections. The obtained cross-section formulas

  18. On the possible bipolar nature of 21 micron IRAS sources

    NASA Technical Reports Server (NTRS)

    Hrivnak, Bruce J.; Kwok, S.

    1991-01-01

    The discovery of another IRAS source (22574 + 6609) showing the unidentified 21-micron emission feature is reported. Its overall energy distribution is similar to the well-known edge-on bipolar nebulae AFGL 2688 and AFGL 618. Ground-based optical and infrared observations of this object and two other 21-micron sources show that while all three have very similar infrared properties, they differ greatly in the visual region. All three of these 21-micron sources are intrinsically similar bipolar nebulae, viewed at different orientations.

  19. Investigation of 14-15 MeV ( n, t) Reaction Cross-sections by Using New Evaluated Empirical and Semi-empirical Systematic Formulas

    NASA Astrophysics Data System (ADS)

    Tel, E.; Aydın, A.; Kaplan, A.; Şarer, B.

    2008-09-01

    In the hybrid reactor, tritium self-sufficiency must be maintained for a commercial power plant. For self-sustaining (D-T) fusion driver tritium breeding ratio should be greater than 1.05. Working out the systematics of ( n, t) reaction cross-sections are of great importance for the definition of the excitation function character for the given reaction taking place on various nuclei at energies up to 20 MeV. In this study we have investigated asymmetry term effect for the ( n, t) reaction cross-sections at 14-15 neutron incident energy. It has been discussed the odd-even effect and the pairing effect considering binding energy systematic of the nuclear shell model for the new experimental data and new cross-sections formulas ( n, t) reactions developed by Tel et al. We have determined a different parameter groups by the classification of nuclei into even-even, even-odd and odd-even for ( n, t) reactions cross-sections. The obtained empirical and semi-empirical formulas by fitting two parameter for ( n, t) reactions were given. All calculated results have been compared with the experimental data and the other semi-empirical formulas.

  20. A Euploid Line of Human Embryonic Stem Cells Derived from a 43,XX,dup(9q),+12,-14,-15,-18,-21 Embryo

    PubMed Central

    Fonseca, Simone Aparecida Siqueira; Costas, Roberta Montero; Morato-Marques, Mariana; Costa, Silvia; Alegretti, Jose Roberto; Rosenberg, Carla; da Motta, Eduardo Leme Alves; Serafini, Paulo C.; Pereira, Lygia V.

    2015-01-01

    Aneuploid embryos diagnosed by FISH-based preimplantation genetic screening (PGS) have been shown to yield euploid lines of human embryonic stem cells (hESCs) with a relatively high frequency. Given that the diagnostic procedure is usually based on the analysis of 1–2 blastomeres of 5 to 10-cell cleavage-stage embryos, mosaicism has been a likely explanation for the phenomena. However, FISH-based PGS can have a significant rate of misdiagnosis, and therefore some of those lines may have been derived from euploid embryos misdiagnosed as aneuploid. More recently, coupling of trophectoderm (TE) biopsy at the blastocyst stage and array-CGH lead to a more informative form of PGS. Here we describe the establishment of a new line of hESCs from an embryo with a 43,XX,dup(9q),+12,-14,-15,-18,-21 chromosomal content based on array-CGH of TE biopsy. We show that, despite the complex chromosomal abnormality, the corresponding hESC line BR-6 is euploid (46,XX). Single nucleotide polymorphism analysis showed that the embryo´s missing chromosomes were not duplicated in BR-6, suggesting the existence of extensive mosaicism in the TE lineage. PMID:26540511

  1. Flood of June 14-15, 1990, in Belmont, Jefferson, and Harrison counties, Ohio, with emphasis on Pipe and Wegee Creek basins near Shadyside

    USGS Publications Warehouse

    Shindel, H.L.

    1991-01-01

    A series of violent thunderstorms caused severe floods and consequent damage in the central part of Ohio during June 14-15, 1990. The eastern part of the State, particularly Belmont, Harrison, and Jefferson Counties, sustained the most damage. In the Pipe and Wegee Creek basins near Shadyside, Belmont County, at least 24 people died and property damage exceeded $10 million. An indirect measurement of discharge on Pipe Creek made near the mouth, indicates a peak discharge of 15,000 ft? /s (cubic feet per second) for the drainage area of 11.3 mi? (square miles) and a unit discharge of 1,330 (ft? /s)/mi? (cubic feet per second per square mile). The recurrence interval for this peak discharge is greater than 100 years. An indirect measurement of discharge of Wegee Creek, made 3 miles upstream from the mouth, indicates a peak discharge of 2,200 (ft? /s) /mi? . The recurrence interval for this peak discharge also is greater than 100 years. Longitudal water-surface profiles showed depths ranging from 7 ft. to 22 ft. The severity of flooding was highly variable. For example, the recurrence interval of the peak discharge at one U.S. Geological Survey streamflow-gaging station was only 2 years, whereas the recurrence interval for the peak discharge was greater than 100 years at another gaging station about 22 miles away.

  2. Effects of a nonionic surfactant (C{sub 14-15} AE-7) on fish survival, growth and reproduction in the laboratory and in outdoor stream mesocosms

    SciTech Connect

    Kline, E.R.; Figueroa, R.A.; Rodgers, J.H. Jr.; Dorn, P.B.

    1996-06-01

    The effects of a nonionic surfactant (C{sub 14-15} AE-7) on survival and growth of juvenile bluegill sunfish and on survival and reproduction of fathead minnows were investigated in the laboratory and in outdoor stream mesocosms. In the laboratory, where the fish were exposed for 10 d, the 96-h LC50 values for bluegill sunfish and fathead minnows were 650 and 770 {micro}g/L, respectively. The no-observed-effect concentration (NOEC) for survival and swimming performance of bluegill sunfish and for survival of fathead minnows was 160 {micro}g/L. The lowest-observed-effect concentration (LOEC) for these toxic responses was 460 {micro}g/L. In the stream mesocosms, where the fish were exposed for 30 d, the NOEC for bluegill sunfish and growth was >330 {micro}g/L. The LOEC for fathead minnow survival was 330 {micro}g/L, and the NOEC was 280 {micro}g/L. Decreased egg laying by fathead minnows was noted in the streams at concentrations of 330 {micro}g/L or greater. Close correspondence between the results of laboratory tests and those obtained under field conditions in the mesocosms indicates that for this surfactant, it may not be necessary to apply ``safety factors`` to extrapolate results from the laboratory to the field.

  3. Injection Seeded/Phase-Conjugated 2-micron Laser System

    NASA Technical Reports Server (NTRS)

    Bai, Yingxin; Yu, Jirong; Petros,M.; Petzar, Paul; Trieu, Bo; Lee, Hyung; Singh, U.; Leyva, V.; Shkunov, V.; Rockwell, D.; Betin, A.; Wang, J.

    2007-01-01

    For the first time, beam quality improvement of 2 micron laser using a fiber based phase conjugation mirror has been demonstrated. Single frequency operation is necessary to lower threshold. The reflectivity of PCM is approx. 50%.

  4. Apparatus for handling micron size range particulate material

    NASA Technical Reports Server (NTRS)

    Friichtenicht, J. F.; Roy, N. L. (Inventor)

    1968-01-01

    An apparatus for handling, transporting, or size classifying comminuted material was described in detail. Electrostatic acceleration techniques for classifying particles as to size in the particle range from 0.1 to about 100 microns diameter were employed.

  5. Release of Micronized Copper Particles from Pressure Treated Wood Products.

    EPA Science Inventory

    Micronized copper pressure treated lumber (PTL) has recently been introduced to the consumer market as a replacement for ionized copper PTL. The presence of particulate rather than aqueous copper raises concerns about possible human or environmental exposure. Two common pathways ...

  6. Improved Fabrication of Lithium Films Having Micron Features

    NASA Technical Reports Server (NTRS)

    Whitacre, Jay

    2006-01-01

    An improved method has been devised for fabricating micron-dimension Li features. This approach is intended for application in the fabrication of lithium-based microelectrochemical devices -- particularly solid-state thin-film lithium microbatteries.

  7. Laser materials for the 0.67-microns to 2.5-microns range

    NASA Technical Reports Server (NTRS)

    Toda, Minoru; Zamerowski, Thomas J.; Ladany, Ivan; Martinelli, Ramon U.

    1987-01-01

    Basic requirements for obtaining injection laser action in III-V semiconductors are discussed briefly. A detailed review is presented of materials suitable for lasers emitting at 0.67, 1.44, 1.93, and 2.5 microns. A general approach to the problem is presented, based on curves of materials properties published by Sasaki et al. It is also shown that these curves, although useful, may need correction in certain ranges. It is deduced that certain materials combinations, either proposed in the literature or actually tried, are not appropriate for double heterostructure lasers, because the refractive index of the cladding material is higher than the index of the active material, thus resulting in no waveguiding, and high threshold currents. Recommendations are made about the most promising approach to the achievement of laser action in the four wavelengths mentioned above.

  8. Characterization of the 1 ^5Πu - 1 ^5Πg Band of C_2 by Two-Color Resonant Four-Wave Mixing and Lif

    NASA Astrophysics Data System (ADS)

    Radi, Peter

    2015-06-01

    The application of two-color resonant four-wave mixing (TC-RFWM) in combination with a discharge slit-source in a molecular beam environment is advantageous for the study of perturbations in C_2. Initial investigations have shown the potential of the method by a detailed deperturbation of the d3Π_g, v=4 state. The deperturbation of the d3Π_g, v=6 state unveiled the presence of the energetically lowest high-spin state of C_2. This dark state gains transition strength through the perturbation process with the d3Π_g, v=6 state yielding weak spectral features that are observable by the high sensitivity of the TC-RFWM technique. The successful deperturbation study of the d3Π_g, v=6 state resulted in the spectroscopic characterization of the quintet (15Πg) and an additional triplet state (d3Π_g, v=19). More recently, investigations have been performed by applying unfolded TC-RFWM to obtain further information on the quintet manifold. The first high-spin transition (15Πu) - 15Πg)) has been observed via an intermediate ``gateway'' state exhibiting both substantial triplet and quintet character owing to the perturbation between the 15Πg), v=0 and the d3Π_g, v=6 states. The high-lying quintet state is found to be predissociative and displays a shallow potential that accommodates three vibrational levels only. Further studies of the high-spin system will be presented in this contribution. By applying TC-RFWM and laser-induced fluorescence, data on the vibrational structure of the 15Πu - 15Πg system is obtained. The results are combined with high-level ab initio computations at the multi-reference configuration interaction (MRCI) level of theory and the largest possible basis currently implemented in the 2012 version of MOLPRO. P. Bornhauser, G. Knopp, T. Gerber, and P.P. Radi, Journal of Molecular Spectroscopy 262, 69 (2010) P. Bornhauser, Y. Sych, G. Knopp, T. Gerber, and P.P. Radi, Journal of Chemical Physics 134, 044302 (2011) Bornhauser, P., Marquardt, R

  9. Mapping of human chromosome Xq28 by two-color fluorescence in situ hybridization of DNA sequences to interphase cell nuclei.

    PubMed Central

    Trask, B J; Massa, H; Kenwrick, S; Gitschier, J

    1991-01-01

    We have used the proximity of probe hybridization sites in interphase chromatin to derive the order of DNA sequences in a 2-3-Mbp region of human chromosome Xq28. The map generated bridges the results of genetic and pulsed-field gel electrophoresis mapping to produce a more complete map of Xq28 than possible with either of these other techniques alone. Two-color fluorescence in situ hybridization (FISH) was used to detect the positions of two or more probes in G1 male interphase nuclei. We show that cosmids that are 50 kbp to 2-3 Mbp apart can be ordered rapidly with two alternative approaches: (1) by comparing the average measured distance between two probes and (2) simply by scoring the order of red and green fluorescent dots after detection of three or more probes with two fluorochromes. The validity of these approaches is demonstrated using five cosmids from a region spanning approximately 800 kbp that includes the factor VIII (F8), glucose-6-phosphate dehydrogenase (G6PD), and color-vision pigment (CV) genes. The cosmid map derived from interphase mapping is consistent with the map determined by restriction-fragment analysis. The two interphase mapping approaches were then used (1) to orient the F8/CV cluster relative to two markers, c1A1 and st14c, which we show by metaphase mapping to be proximal to the F8/CV cluster, (2) to position st14c (DXS52) between c1A1 and F8, and (3) to orient the CV gene cluster relative to G6PD by using two CV-flanking cosmids, 18b41 and fr7. The probe order in Xq28 derived from interphase proximity is cen-c1A1-st14c-5'F8 (p624-p542-p625)-G6PD-18b41-3' green-green-red-fr7-tel. We also show that, to determine their order by using metaphase chromosomes, sequences must be at least 1 Mbp apart, an order of magnitude greater than required in interphase chromatin. The data show that FISH mapping is a simple way to order sequences separated by greater than or equal to 50 kbp for the construction of long-range maps of mammalian genomes

  10. High-sensitivity two-color detection of double-stranded DNA with a confocal fluorescence gel scanner using ethidium homodimer and thiazole orange.

    PubMed Central

    Rye, H S; Quesada, M A; Peck, K; Mathies, R A; Glazer, A N

    1991-01-01

    Ethidium homodimer (EthD; lambda Fmax 620 nm) at EthD:DNA ratios up to 1 dye:4-5 bp forms stable fluorescent complexes with double-stranded DNA (dsDNA) which can be detected with high sensitivity using a confocal fluorescence gel scanner (Glazer, A.N., Peck, K. & Mathies, R.A. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 3851-3855). However, on incubation with unlabeled DNA partial migration of EthD takes place from its complex with dsDNA to the unlabeled DNA. It is shown here that this migration is dependent on the fractional occupancy of intercalating sites in the original dsDNA-EthD complex and that there is no detectable transfer from dsDNA-EthD complexes formed at 50 bp: 1 dye. The monointercalator thiazole orange (TO; lambda Fmax 530 nm) forms readily dissociable complexes with dsDNA with a large fluorescence enhancement on binding (Lee, L.G., Chen, C. & Liu, L.A. (1986) Cytometry 7, 508-517). However, a large molar excess of TO does not displace EthD from its complex with dsDNA. When TO and EthD are bound to the same dsDNA molecule, excitation of TO leads to efficient energy transfer from TO to EthD. This observation shows the practicability of 'sensitizing' EthD fluorescence with a second intercalating dye having a very high absorption coefficient and efficient energy transfer characteristics. Electrophoresis on agarose gels, with TO in the buffer, of preformed linearized M13mp18 DNA-EthD complex together with unlabeled linearized pBR322 permits sensitive fluorescence detection in the same lane of pBR322 DNA-TO complex at 530 nm and of M13mp18 DNA-EthD complex at 620 nm. These observations lay the groundwork for the use of stable DNA-dye intercalation complexes carrying hundreds of chromophores in two-color applications such as the physical mapping of chromosomes. Images PMID:2014172

  11. High-resolution maps of Jupiter at five microns.

    NASA Technical Reports Server (NTRS)

    Keay, C. S. L.; Low, F. J.; Rieke, G. H.; Minton, R. B.

    1973-01-01

    The distribution of 5-micron radiation, emitted from a large number of discrete sources from Jupiter, was observed during the 1972 apparition. These sources are less bright than those observed by Westphal (1969). At least 50 discrete sources having brightness temperatures exceeding 227 K were revealed which were mainly located within three narrow-latitude bands. Strong correlation exists between the 5-micron brightness temperatures of Jovian features and their colors as recorded photographically.

  12. Micron Accuracy Deployment Experiment (MADE), phase A. Volume 1

    NASA Technical Reports Server (NTRS)

    Peterson, Lee D.; Lake, Mark S.

    1995-01-01

    This report documents a Phase A In-STEP flight experiment development effort. The objective of the experiment is to deploy a portion of a segmented reflector on the Shuttle and study its micron-level mechanics. Ground test data are presented which projects that the on-orbit precision of the test article should be approximately 5 microns. Extensive hardware configuration development information is also provided.

  13. wssa_utils: WSSA 12 micron dust map utilities

    NASA Astrophysics Data System (ADS)

    Meisner, Aaron M.; Finkbeiner, Douglas P.

    2014-02-01

    wssa_utils contains utilities for accessing the full-sky, high-resolution maps of the WSSA 12 micron data release. Implementations in both Python and IDL are included. The code allows users to sample values at (longitude, latitude) coordinates of interest with ease, transparently mapping coordinates to WSSA tiles and performing interpolation. The wssa_utils software also serves to define a unique WSSA 12 micron flux at every location on the sky.

  14. Laser damage tests on InSb photodiodes at 1.064 micron and 0.532 micron

    NASA Technical Reports Server (NTRS)

    Bearman, G. H.; Staller, C.; Mahoney, C.

    1992-01-01

    InSb photodiodes were examined for performance degradation after pulsed laser illumination at 0.532 micron and 1.064 micron. Incident laser powers ranged from 6 x 10 exp-18 micron-watts to 16 micron-watts in a 50 pm diameter spot. Dark current and spectral response were both measured before and after illumination. Dark current measurements were taken with the diode blanked off and viewing only 77 K surfaces. Long term stability tests demonstrated that the blackbody did not exhibit long term drifts. Other tests showed that room temperature variations did not affect the diode signal chain or the digitization electronics used in data acquisition. Results of the experiment show that the diodes did not exhibit changes in dark current or spectral response performance as a result of the laser illumination. A typical change in diode spectral response (before/after laser exposure) was about 0.2 percent +/- 0.2 percent.

  15. Simultaneous scoring of 10 chromosomes (9,13,14,15,16,18,21,22,X, and Y) in interphase nuclei by using spectral imaging

    NASA Astrophysics Data System (ADS)

    Fung, Jingly; Weier, Heinz-Ulli G.; Goldberg, James D.; Pedersen, Roger A.

    1999-06-01

    Numerical aberrations involving parts of or entire chromosomes have detrimental effects on mammalian embryonic, and perinatal development. Only few fetuses with chromosomal imbalances survive to term, and their abnormalities lead to stillbirth or cause severely altered phenotypes in the offspring (such as trisomies involving chromosomes 13, 18, 21, and anomalies of X, and Y). Because aneuploidy of any of the 24 chromosomes will have significant consequences, an optimized preimplantation and prenatal genetic diagnosis (PGD) test will score all the chromosomes. Since most cells to be analyzed will be in interphase rather than metaphase, we developed a rapid procedure for the analysis of interphase cells such as lymphocytes, amniocytes, or early embryonic cells (blastomeres). Our approach was based on in situ hybridization of chromosome-specific non-isotopically labeled DNA probes and Spectral Imaging. The Spectral Imaging system uses an interferometer instead of standard emission filters in a fluorescence microscope to record high resolution spectra from fluorescently stained specimens. This bio-imaging system combines the techniques of fluorescence optical microscopy, charged coupled device imaging, Fourier spectroscopy, light microscopy, and powerful analysis software. The probe set used here allowed simultaneous detection of 10 chromosomes (9, 13, 14, 15, 16, 18, 21, 22, X, Y) in interphase nuclei. Probes were obtained commercially or prepared in-house. Following 16 - 40 h hybridization to interphase cells and removal of unbound probes, image spectra (range 450 - 850 nm, resolution 10 nm) were recorded and analyzed using an SD200 Spectral Imaging system (ASI, Carlsbad, CA). Initially some amniocytes were unscoreable due to their thickness, and fixation protocols had to be modified to achieve satisfactory results. In summary, this study shows the simultaneous detection of at least 10 different chromosomes in interphase cells using a novel approach for multi

  16. Prescribed 3-D Direct Writing of Suspended Micron/Sub-micron Scale Fiber Structures via a Robotic Dispensing System

    PubMed Central

    Yuan, Hanwen; Cambron, Scott D.; Keynton, Robert S.

    2015-01-01

    A 3-axis dispensing system is utilized to control the initiating and terminating fiber positions and trajectory via the dispensing software. The polymer fiber length and orientation is defined by the spatial positioning of the dispensing system 3-axis stages. The fiber diameter is defined by the prescribed dispense time of the dispensing system valve, the feed rate (the speed at which the stage traverses from an initiating to a terminating position), the gauge diameter of the dispensing tip, the viscosity and surface tension of the polymer solution, and the programmed drawing length. The stage feed rate affects the polymer solution’s evaporation rate and capillary breakup of the filaments. The dispensing system consists of a pneumatic valve controller, a droplet-dispensing valve and a dispensing tip. Characterization of the direct write process to determine the optimum combination of factors leads to repeatedly acquiring the desired range of fiber diameters. The advantage of this robotic dispensing system is the ease of obtaining a precise range of micron/sub-micron fibers onto a desired, programmed location via automated process control. Here, the discussed self-assembled micron/sub-micron scale 3D structures have been employed to fabricate suspended structures to create micron/sub-micron fluidic devices and bioengineered scaffolds. PMID:26132732

  17. Ultra-low emittance beam generation using two-color ionization injection in a CO2 laser-driven plasma accelerator

    SciTech Connect

    Schroeder, Carl; Benedetti, Carlo; Bulanov, Stepan; Chen, Min; Esarey, Eric; Geddes, Cameron; Vay, J.; Yu, Lule; Leemans, Wim

    2015-05-21

    Ultra-low emittance (tens of nm) beams can be generated in a plasma accelerator using ionization injection of electrons into a wakefield. An all-optical method of beam generation uses two laser pulses of different colors. A long-wavelength drive laser pulse (with a large ponderomotive force and small peak electric field) is used to excite a large wakefield without fully ionizing a gas, and a short-wavelength injection laser pulse (with a small ponderomotive force and large peak electric field), co-propagating and delayed with respect to the pump laser, to ionize a fraction of the remaining bound electrons at a trapped wake phase, generating an electron beam that is accelerated in the wake. The trapping condition, the ionized electron distribution, and the trapped bunch dynamics are discussed. Expressions for the beam transverse emittance, parallel and orthogonal to the ionization laser polarization, are presented. An example is shown using a 10-micron CO2 laser to drive the wake and a frequency-doubled Ti:Al2O3 laser for ionization injection.

  18. Titan's 5-micron spectrum: VLT/ISAAC observations

    NASA Astrophysics Data System (ADS)

    Lellouch, E.; Coustenis, A.; Sebag, B.; Cuby, J.-G.; Crovisier, J.; Maillard, J. P.

    2001-11-01

    Earlier observations by Noll and Knacke (Icarus, 101, 272, 1993) and Noll et al. (Icarus, 124, 625, 1996) have shown that the 5 micron region of Titan's spectrum is a methane window probing Titan's lower atmosphere and surface. In particular, Noll et al. found that the 4.8-4.95 micron radiation is dominated by absorption in the (1-0) vibrational band of CO in Titan's troposphere, and that the 4.95-5.2 micron flux is reflected at the surface. They inferred a 10 ppm tropospheric CO mixing ratio, but this value was uncertain because of limited S/N of their data, which in particular did not show the individual rovibrational lines of CO. On November 16, 2000, we observed Titan near Eastern Elongation with the 8-m UT1 (Antu) of the Very Large Telescope, equipped with the Infrared Spectrometer and Array Camera (ISAAC). The insrument was used in long slit spectroscopy mode. The 4.75-5.1 micron range was covered, at a mean resolution of about 2000. Standard reduction included flat-fielding, correction for horizontal distortion and slit curvature, spectrum extraction, correction for telluric absorption, and wavelength and flux calibration. Preliminary results indicate that (i) the continuum flux at 5.0 micron is about 100 mJy (indicating a geometric albedo of 0.055), consistent with Noll et al. 1996 (ii) the albedo tends to decrease longward of 5.0 micron (iii) residual flux is detected at 4.75-4.83 micron (iv) several rovibrational lines of CO are seen in absorption (P10 to P19 of 13CO) at 4.85-4.95 micron. We will present the analysis of these data and infer a new measurement of the CO abundance in Titan's troposphere, contributing to the long-standing problem of the abundance, vertical distribution and origin of carbon monoxide on Titan. In addition, the spectrum seems to show emission features at 4.75-4.83 micron coinciding with the position of some CO(1-0) lines; however stratospheric thermal emission and solar induced fluorescence seem to be unable to explain

  19. Spectral structure near the 11.3 micron emission feature

    NASA Technical Reports Server (NTRS)

    Witteborn, Fred C.; Sandford, Scott A.; Bregman, Jesse D.; Allamandola, Louis J.; Cohen, M.; Wooden, Diane

    1989-01-01

    If the 11.3 micron emission feature seen in the spectra of many planetary nebulae, H II regions, and reflection nebulae is attributable to polycyclic aromatic hydrocarbons (PAHs), then additional features should be present between 11.3 and 13.0 microns. Moderate resolution spectra of NGC 7027, HD 44179, BD+30 deg 3639, and IRAS 21282+5050 are presented which show evidence for new emission features centered near 12.0 and 12.7 microns. These are consistent with an origin from PAHs and can be used to constrain the molecular structure of the family of PAHs responsible for the infrared features. There is an indication that coronene-like PAHs contribute far more to the emission from NGC 7027 than to the emission from HD 44179. The observed asymmetric profile of the 11.3 micron band in all the spectra is consistent with the slight anharmonicity expected in the C-H out-of-plane bending mode in PAHs. A series of repeating features between 10 and 11 microns in the spectrum of HD 44179 suggests a simple hydride larger than 2 atoms is present in the gas phase in this object.

  20. Visibility related to backscatter at 1.54 micron

    NASA Technical Reports Server (NTRS)

    Barber, T. L.; Larson, D. R.

    1986-01-01

    The lidar process was shown to have the necessary potential to fulfill the need for a remote measurement of visibility. Visibility can be inferred from a lidar return optical extinction. The wavelength 1.54 micron was chosen, being near the visible wavelength region and having a high eye safety threshol, 200,000 times higher than 1.06 micron; 1.54 is the erbium laser wavelength. This research utilized 105 measured height profiles of natural droplet size distributions data, taken in clouds, fog, and haze. These profiles were examined to determine the completeness of the droplet counting data. It was found that the particle spectrometer data were incomplete in the very light ford and haze so this portion of the data was eliminated. Utilizing the Mie theory, these droplet size distribution profiles were converted to backscatter at 1.54 micron and extinction in the visible region, 0.55 micron. Using Koschmeider's relationship, the extinction profiles were converted to visibility. The visibility and backscatter profiles were compared to develop a relationship between visibility and backscatter at 1.54 micron.

  1. Post-Hurricane Ike coastal oblique aerial photographs collected along the Alabama, Mississippi, and Louisiana barrier islands and the north Texas coast, September 14-15, 2008

    USGS Publications Warehouse

    Morgan, Karen L. M.; Krohn, M. Dennis; Guy, Kristy K.

    2016-01-01

    The U.S. Geological Survey (USGS), as part of the National Assessment of Coastal Change Hazards project, conducts baseline and storm-response photography missions to document and understand the changes in vulnerability of the Nation's coasts to extreme storms (Morgan, 2009). On September 14-15, 2008, the USGS conducted an oblique aerial photographic survey along the Alabama, Mississippi, and Louisiana barrier islands and the north Texas coast, aboard a Beechcraft Super King Air 200 (aircraft) at an altitude of 500 feet (ft) and approximately 1,200 ft offshore. This mission was flown to collect post-Hurricane Ike data for assessing incremental changes in the beach and nearshore area since the last survey, flown on September 9-10, 2008, and the data can be used in the assessment of future coastal change.The photographs provided in this report are Joint Photographic Experts Group (JPEG) images. ExifTool was used to add the following to the header of each photo: time of collection, Global Positioning System (GPS) latitude, GPS longitude, keywords, credit, artist (photographer), caption, copyright, and contact information. The photograph locations are an estimate of the position of the aircraft at the time the photograph was taken and do not indicate the location of any feature in the images (see the Navigation Data page). These photographs document the state of the barrier islands and other coastal features at the time of the survey. Pages containing thumbnail images of the photographs, referred to as contact sheets, were created in 5-minute segments of flight time. These segments can be found on the Photos and Maps page. Photographs can be opened directly with any JPEG-compatible image viewer by clicking on a thumbnail on the contact sheet.In addition to the photographs, a Google Earth Keyhole Markup Language (KML) file is provided and can be used to view the images by clicking on the marker and then clicking on either the thumbnail or the link above the thumbnail

  2. MSX Observations of the Eclipsed Moon at 4 Microns

    NASA Astrophysics Data System (ADS)

    Howard, J. W.; Little, S. J.; Murdock, T. L.

    1997-07-01

    The lunar eclipse of September 27, 1996 presented the opportunity to observe the 4 micron emission from the moon during totality. The Midcourse Space Experiment (MSX) satellite made observations three times during the totality phase of the eclipse. These observations in Bands B1 (4.22 - 4.36 microns) and B2 (4.24 - 4.45 microns) were used to construct images of the eclipsed moon. The images have been analyzed for temperature and location of thermal anomalies on the moon as well as for temperatures of extended maria and highland areas. Maps of the moon to illustrate the location and brightness of thermal anomalies first seen by Saari and Shorthill (1965) and temperature comparisons with microwave measurements of selected regions on the moon (Sandor and Clancy, 1995) will be made. References: Saari, J. M., and R. W. Shorthill, 1965, Nature, 205, p. 964. Sandor, Brad J., and R. Todd Clancy, 1995, Icarus, 115, p. 387.

  3. Metallization technology for tenth-micron range integrated circuits

    SciTech Connect

    Berry, L.A.; Harper, M.E.

    1996-11-27

    A critical step in the fabrication of integrated circuits is the deposition of metal layers which interconnect the various circuit elements that have been formed in earlier process steps. In particular, columns of copper several times higher than the characteristic dimension of the circuit elements was needed. Features with a diameter of a few tenths of a micron and a height of about one micron need to be filled at rates in the half to one micron per minute range. With the successful development of a copper deposition technology meeting these requirements, integrated circuits with simpler designs and higher performance could be economically manufactured. Several technologies for depositing copper were under development. No single approach had an optimum combination of performance (feature characteristics), cost (deposition rates), and manufacturability (integration with other processes and tool reliability). Chemical vapor deposition, plating, sputtering and ionized-physical vapor deposition (I-PVD) were all candidate technologies. Within this project, the focus was on I-PVD.

  4. The Beauty and Limitations of 10 Micron Heterodyne Interferometry (ISI)

    NASA Technical Reports Server (NTRS)

    Danchi, William C.

    2003-01-01

    Until recently, heterodyne interferometry at 10 microns has been the only successful technique for stellar interferometry in the very difficult atmospheric window from 9-12 microns. For most of its operational lifetime the U.C. Berkeley Infrared Spatial Interferometer was a single-baseline two telescope (1.65 m aperture) system using CO2 lasers as local oscillators. This instrument was designed and constructed from 1983-1988, and first fringes were obtained at Mt. Wilson in June 1988. During the past few years, a third telescope was constructed and just recently the first closure phases were obtained at 11.15 microns. We discuss the history, physics and technology of heterodyne interferometry in the mid-infrared, and some key astronomical results that have come from this unique instrument.

  5. 2--14 microns Spectroscopy of Vega-type Stars

    NASA Astrophysics Data System (ADS)

    Fajardo-Acosta, S. B.; Knacke, R. F.; Hackwell, J. A.; Lynch, D. K.; Russell, R. W.; Hanner, M. S.

    1994-12-01

    We present intermediate-resolution (lambda /Delta lambda ~ 50) infrared (2--14 microns) spectroscopy of four early-type main-sequence stars, conducted with the Aerospace Corp. Infrared Spectrograph. We observed beta UMa (A1 V), alpha Aql (A7 V), and beta Leo (A3 V) at the 1.3-m KPNO telescope in May 1993, and zeta Lep (A2 V) at the 3.0-m IRTF telescope in Nov. 1993. The Vega-type stars beta UMa and zeta Lep showed weak but definite excess flux at ~ 10 microns in previous groundbased photometric surveys (Fajardo-Acosta, Telesco & Knacke 1994, in preparation; Aumann & Probst 1991, ApJ, 368, 264). We observed alpha Aql and beta Leo to confirm that their ~ 10 microns spectra do not show any excess. The weak ~ 10 microns excess features in our spectra of beta UMa and zeta Lep are probably indicative of large grains and/or a small quantity of dust around these stars. Their weak features contrast with the prominent silicate emission feature previously seen in beta Pic and 51 Oph. The grains are hotter in zeta Lep than in beta UMa, as indicated by an excess already present at short wavelengths ( ~ 8.5 microns) in the spectrum of the former, as opposed to the 10--11 microns excess of the latter. Dust around these two stars could be an assemblage of amorphous minerals, probably of a variety of sizes, as suggested by their broad features. We compared the excess spectra of zeta Lep and beta UMa with those of comets (reviewed by Hanner, Lynch, & Russell 1994, ApJ, 425, 274) and found they resemble those of dust-poor comets such as Austin 1990 V and Okazaki-Levy-Rudenko 1989 XIX.

  6. Thermal emission from Saturn's rings at 380 microns

    SciTech Connect

    Roellig, T.L.; Werner, M.W.; Becklin, E.E.

    1988-03-01

    Two different techniques have been used to derive the Saturn disk's ring brightness temperatures from 380-micron observations: (1) comparisons of these wide-beam observation disk-ring system results with those obtained for an earlier epoch, when the rings were edge-on, then differencing the two measurements to obtain a value for the rings' contribution; and (2) ring contribution resolution during scanning along the disk-ring plane, to yield a B-ring brightness temperature of 39 + or - 8 K at 380 microns. The results obtained indicate a gradual decrease of observed ring brightness temperature from the IR to the radio wavelength range. 24 references.

  7. Thermal emission from Saturn's rings at 380 microns

    NASA Technical Reports Server (NTRS)

    Roellig, Thomas L.; Werner, Michael W.; Becklin, Eric E.

    1988-01-01

    Two different techniques have been used to derive the Saturn disk's ring brightness temperatures from 380-micron observations: (1) comparisons of these wide-beam observation disk-ring system results with those obtained for an earlier epoch, when the rings were edge-on, then differencing the two measurements to obtain a value for the rings' contribution; and (2) ring contribution resolution during scanning along the disk-ring plane, to yield a B-ring brightness temperature of 39 + or - 8 K at 380 microns. The results obtained indicate a gradual decrease of observed ring brightness temperature from the IR to the radio wavelength range.

  8. Discovery of new 2 micron sources in Rho Ophiuchi

    NASA Technical Reports Server (NTRS)

    Barsony, M.; Carlstrom, J. E.; Burton, Michael G.; Russell, A. P. G.; Garden, R.

    1989-01-01

    A 144-sq-arcmin region of the Rho Oph star-forming cloud core was surveyed at 2.2 microns, complete to mK = 14. A total of 61 sources are detected, 26 of which have been previously reported, accounting for a total of 35 new sources with mK = 12-14. There is no turnover in the 2-micron luminosity function of the Rho Oph cloud core to a limiting sensitivity of mK = 14. Two of the newly discovered sources are binary companions to previously cataloged objects.

  9. Imaging antenna array at 119 microns. [for plasma diagnostics

    NASA Technical Reports Server (NTRS)

    Neikirk, N. P.; Tong, P. P.; Putledge, D. B.; Park, H.; Young, P. E.

    1982-01-01

    A focal-plane imaging antenna array has been demonstrated at 119 microns. The array is a line of evaporated silver bow-tie antennas with bismuth microbolometer detectors on a silicon substrate. Radiation is coupled into the array by a lens placed on the back of the substrate. The bolometers are thermally isolated from the silicon substrate with a half-micron layer of polyimide. The array performance is demonstrated by coherent imaging of a series of holes at half the diffraction-limited cut-off frequency.

  10. Planetary observations at a wavelength of 355 microns

    SciTech Connect

    De pater, I.; Ulich, B.L.; Kreysa, E.; Chini, R.; Kaman Aerospace Corp., Tucson, AZ; Max-Planck-Institut fuer Radioastronomie, Bonn )

    1989-05-01

    Brightness temperature measurements have been conducted for Jupiter, Saturn, Uranus, and Neptune, as well as the Galilean satellites Europa, Ganymede, and Callisto, and the asteroid Ceres, at 355 microns. The precise shape of the spectra of these bodies can be used to obtain information on their composition and the state of compactness of their surface/subsurface layers. The temperatures obtained for the giant planets agree with both previous measurements and model atmosphere calculations; the present result for Jupiter is noted to be consistent with a model atmosphere spectrum lacking a CH3-ice cloud, or perhaps with one having small (10-micron) particles. 12 refs.

  11. The interstellar dust model of comet dust constrained by 3.4 micron and 10 micron emission

    NASA Astrophysics Data System (ADS)

    Greenburg, J. M.; Zhao, N. S.; Hage, J. I.

    The morphological structure and chemical composition of submicron-sized interstellar dust grains which have undergone cold aggregation in the presolar nebular are studied to derived the bulk and microstructure of comet nuclei. The density, size distribution, and chemical composition of comet dust are deduced from observations at 3.4 and 10 microns. It is found that the 10-micron emission of Comet Halley is produced by predominantly interstellar amorphous silicates with a small admixture of crystalline silicates. In addition, it is shown that the number of small comet particles with masses less than 10 to the -9th g must be substantially larger than has generally been assumed.

  12. Advancement in 17-micron pixel pitch uncooled focal plane arrays

    NASA Astrophysics Data System (ADS)

    Li, Chuan; Skidmore, George; Howard, Christopher; Clarke, Elwood; Han, C. J.

    2009-05-01

    This paper provides an update of 17 micron pixel pitch uncooled microbolometer development at DRS. Since the introduction of 17 micron pitch 640x480 focal plane arrays (FPAs) in 2006, significant progress has been made in sensor performance and manufacturing processes. The FPAs are now in initial production with an FPA noise equivalent temperature difference (NETD), detector thermal time constant, and pixel operability equivalent or better than that of the current 25 micron pixel pitch production FPAs. NETD improvement was achieved without compromising detector thermal response or thermal time constant by simultaneous reduction in bolometer heat capacity and thermal conductance. In addition, the DRS unique "umbrella" microbolometer cavities were optically tuned to optimize detector radiation absorption for specific spectral band applications. The 17 micron pixel pitch FPAs are currently being considered for the next generation soldier systems such as thermal weapon sights (TWS), vehicle driver vision enhancers (DVE), digitally fused enhanced night vision goggles (DENVG) and unmanned air vehicle (UAV) surveillance sensors, because of overall thermal imaging system size, weight and power advantages.

  13. Validar: A Testbed for Advanced 2-Micron Doppler Lidar

    NASA Technical Reports Server (NTRS)

    Koch, Grady J.; Petros, Mulugeta; Barnes, Bruce W.; Beyon, Jeffrey Y.; Amzajerdian, Farzin; Yu, Jirong; Kavaya, Michael J.; Singh, Upendra N.

    2004-01-01

    High-energy 2-microns lasers have been incorporated in a breadboard coherent Doppler lidar to test component technologies and explore applications for remote sensing of the atmosphere. Design of the lidar is presented including aspects in the laser transmitter, receiver, photodetector, and signal processing. Sample data is presented on wind profiling and CO2 concentration measurements.

  14. Micron-gap thermophotovoltaic systems enhanced by nanowires

    NASA Astrophysics Data System (ADS)

    Mirmoosa, Mohammad Sajjad; Simovski, Constantin

    2015-01-01

    We introduce new micron-gap thermophotovoltaic systems enhanced by tungsten nanowires. We theoretically show that these systems allow the frequency-selective super-Planckian spectrum of radiative heat transfer that promises a very efficient generation of electricity. Our system analysis covers practical aspects such as output power per unit area and efficiency of the tap water cooling.

  15. Improved whisker pointing technique for micron-size diode contact

    NASA Technical Reports Server (NTRS)

    Mattauch, R. J.; Green, G.

    1982-01-01

    Pointed phosphor-bronze whiskers are commonly used to contact micron-size Schottky barrier diodes. A process is presented which allows pointing such wire and achieving the desired cone angle and tip diameter without the use of highly undesirable chemical reagents.

  16. Release of Micronized Copper Particles from Pressure Treated Wood Products

    EPA Science Inventory

    Micronized copper pressure treated lumber (PTL) has recently been introduced to the consumer market as a replacement for ionized copper PTL. The presence of particulate rather than aqueous copper raises concerns about the exposure of humans as well as the environment to the parti...

  17. Biogeography of a human oral microbiome at the micron scale

    PubMed Central

    Mark Welch, Jessica L.; Rossetti, Blair J.; Rieken, Christopher W.; Dewhirst, Floyd E.; Borisy, Gary G.

    2016-01-01

    The spatial organization of complex natural microbiomes is critical to understanding the interactions of the individual taxa that comprise a community. Although the revolution in DNA sequencing has provided an abundance of genomic-level information, the biogeography of microbiomes is almost entirely uncharted at the micron scale. Using spectral imaging fluorescence in situ hybridization as guided by metagenomic sequence analysis, we have discovered a distinctive, multigenus consortium in the microbiome of supragingival dental plaque. The consortium consists of a radially arranged, nine-taxon structure organized around cells of filamentous corynebacteria. The consortium ranges in size from a few tens to a few hundreds of microns in radius and is spatially differentiated. Within the structure, individual taxa are localized at the micron scale in ways suggestive of their functional niche in the consortium. For example, anaerobic taxa tend to be in the interior, whereas facultative or obligate aerobes tend to be at the periphery of the consortium. Consumers and producers of certain metabolites, such as lactate, tend to be near each other. Based on our observations and the literature, we propose a model for plaque microbiome development and maintenance consistent with known metabolic, adherence, and environmental considerations. The consortium illustrates how complex structural organization can emerge from the micron-scale interactions of its constituent organisms. The understanding that plaque community organization is an emergent phenomenon offers a perspective that is general in nature and applicable to other microbiomes. PMID:26811460

  18. The NASA - Arc 10/20 micron camera

    NASA Technical Reports Server (NTRS)

    Roellig, T. L.; Cooper, R.; Deutsch, L. K.; Mccreight, C.; Mckelvey, M.; Pendleton, Y. J.; Witteborn, F. C.; Yuen, L.; Mcmahon, T.; Werner, M. W.

    1994-01-01

    A new infrared camera (AIR Camera) has been developed at NASA - Ames Research Center for observations from ground-based telescopes. The heart of the camera is a Hughes 58 x 62 pixel Arsenic-doped Silicon detector array that has the spectral sensitivity range to allow observations in both the 10 and 20 micron atmospheric windows.

  19. The 100 micron detector development program. [gallium doped germanium photoconductors

    NASA Technical Reports Server (NTRS)

    Moore, W. J.

    1976-01-01

    An effort to optimize gallium-doped germanium photoconductors (Ge:Ga) for use in space for sensitive detection of far infrared radiation in the 100 micron region is described as well as the development of cryogenic apparatus capable of calibrating detectors under low background conditions.

  20. The protective effect of astrocyte-derived 14,15-EET on H2O2-induced cell injury in Astrocyte-dopaminergic neuronal cell line co-culture

    PubMed Central

    Terashvili, Maia; Sarkar, Pallabi; Van Nostrand, Meg; Falck, John R.; Harder, David R.

    2014-01-01

    Astrocytes perform several functions that are essential for normal neuronal activity. They play a critical role in neuronal survival during ischemia and other degenerative injuries and also modulate neuronal recovery by influencing neurite outgrowth. In this study, we investigated the neuroprotective effects of astrocyte-derived 14,15-epoxyeicosatrienoic acid (14,15-EET), metabolite of arachidonic acid by Cytochrome P450 epoxygenases (CYP), against oxidative stress induced by hydrogen peroxide (H2O2). We found that dopaminergic neuronal cells (N27 cell line) stimulated with two different doses of H2O2 (0.1 and 1 mM) for 1h showed decreased cell viability compared to the control group, while astrocytes co-cultured with dopaminergic neuronal cell lines prevented cell during after stimulation with the same doses of H2O2 for 1h. Dopaminergic neuronal cells (N27 cell line) pretreated with different doses of 14, 15-EET (0.1–30 μM, 30 min) before H2O2 stimulation also showed increased cell viability. Furthermore, pre-treatment of the co-cultured cells with 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA), an inhibitor of the EET metabolizing enzyme, soluble epoxide hydrolase (sEH), before H2O2 stimulation (1 mM, for 1h) increased cell viability. It also increased the endogenous level of 14,15-EET in the media compared to control group. However, pretreatment with the CYP epoxygenase inhibitor miconazole (1–20 μM, 1h) before H2O2 (1 mM, 1h) stimulation showed decreased cell viability. Our data suggest that 14,15-EET which is released from astrocytes, enhances cell viability against oxidant induced injury. Further understanding of the mechanism of 14,15-EET-mediated protection in dopaminergic neurons is imperative, as it could lead to novel therapeutic approaches for treating CNS neuropathologies, such as Parkinson’s disease. PMID:22863680

  1. Variability of Jupiter's Five-Micron Hot Spot Inventory

    NASA Technical Reports Server (NTRS)

    Yanamandra-Fisher, Padma A.; Orton, G. S.; Wakefield, L.; Rogers, J. H.; Simon-Miller, A. A.; Boydstun, K.

    2012-01-01

    Global upheavals on Jupiter involve changes in the albedo of entire axisymmetric regions, lasting several years, with the last two occurring in 1989 and 2006. Against this backdrop of planetary-scale changes, discrete features such as the Great Red Spot (GRS), and other vortices exhibit changes on shorter spatial- and time-scales. We track the variability of the discrete equatorial 5-micron hot spots, semi-evenly spaced in longitude and confined to a narrow latitude band centered at 6.5degN (southern edge of the North Equatorial Belt, NEB), abundant in Voyager images. Tantalizingly similar patterns were observed in the visible (bright plumes and blue-gray regions), where reflectivity in the red is anti-correlated with 5-microns thermal radiance. Ortiz et al. (1998, GRL, 103) characterized the latitude and drift rates of the hot spots, including the descent of the Galileo probe at the southern edge of a 5-micron hot spot, as the superposition of equatorial Rossby waves, with phase speeds between 99 - 103m/s, relative to System III. We note that the high 5-micron radiances correlate well but not perfectly with high 8.57-micron radiances. Because the latter are modulated primarily by changes in the upper ammonia (NH3) ice cloud opacity, this correlation implies that changes in the ammonia ice cloud field may be responsible for the variability seen in the 5-m maps. During the NEB fade (2011 - early 2012), however, these otherwise ubiquitous features were absent, an atmospheric state not seen in decades. The ongoing NEB revival indicates nascent 5-m hot spots as early as April 2012, with corresponding visible dark spots. Their continuing growth through July 2012 indicates the possit.le re-establishment of Rossby waves. The South Equatorial Belt (SEB) and NEB revivals began similarly with an instability that developed into a major outbreak, and many similarities in the observed propagation of clear regions.

  2. Saturn's Deep Cloud Structure Derived From 5-Micron Spectra

    NASA Astrophysics Data System (ADS)

    Bjoraker, G. L.; Chanover, N. J.; Glenar, D. A.; Hewagama, T.

    2007-12-01

    The CSHELL and SpeX spectrometers on NASA's Infrared Telescope Facility were used to observe Saturn between 4.5 and 5.4 microns on several occasions from 2004-2007 at the same time as Cassini/VIMS and CIRS were mapping the planet. At these wavelengths thermal radiation originates from the deep atmosphere (5 bars) and it is attenuated by two cloud layers considered in equilibrium models to be composed of NH4SH and condensed NH3. In addition, there is a component of sunlight reflected from the upper (NH3) cloud that varies spatially on Saturn. CSHELL can spectrally resolve profiles of absorption lines of ammonia (NH3) and phosphine (PH3) on Saturn at selected wavelengths. These lines are very broad due to collisions with 3 to 5 bars of hydrogen. The Saturn spectrum exhibits numerous strong NH3 and PH3 lines, as well as Fraunhofer lines due to CO in the Sun. SpeX observations cover the entire 5-micron window sampling both thermal emission and reflected sunlight. Image cubes were obtained by stepping the slit across the planet. The best contrast in reconstructed images occurs at 5.05 microns, which coincides with the wavelength where VIMS sees spectacular structure on Saturn. The spatial variation of Saturn's 5-micron spectrum is dominated by the variable opacity of its deep cloud structure. Superimposed on this are smaller variations in the mixing ratios of NH3 and PH3. The abundances of these gases can be retrieved reliably in relatively cloud-free regions between 50 South and 65 South, which are analogous to Jupiter's belts and 5-micron hot spots. Elsewhere, it is more difficult to separate changes in cloud opacity from gas abundances. We use near-simultaneous CIRS observations which sound the ~500-mbar level to provide an upper boundary condition to PH3. The 5-micron spectrum of Saturn's Equatorial Zone (10 South) is significantly different from a region near 60 South. The NH3 and PH3 lines are weaker and narrower in the EQZ, while the Fraunhofer lines are stronger

  3. A reevaluation of the 20-micron magnitude system

    NASA Technical Reports Server (NTRS)

    Tokunaga, A. T.

    1984-01-01

    The 20-micron infrared magnitude system is reexamined by observing primary infrared standards and seven A V stars. The purpose is to determine whether Alpha Lyr has colors consistent with the average of A0 stars and to determine the relative magnitude of the primary standards to that of Alpha Lyr. The data presented are consistent with the interpretation that the spectrum of Alpha Lyr is a blackbody and that it is a viable flux standard at 10 and 20 microns. The absolute flux density scale, the physical quantity of interest, is found to be consistent with an extrapolation of the Alpha Lyr spectrum from the near infrared on the basis of the comparison of stars to Mars and asteroids. Adoption of a 0.0 magnitude for Alpha Lyr requires that the magnitudes given by Morrison and Simon (1973) and by Simon et al. (1972) be revised downward by 0.14 mag.

  4. Infrared reflectance spectra (4-12 micron) of lunar samples

    NASA Technical Reports Server (NTRS)

    Nash, Douglas B.

    1991-01-01

    Presented here are infrared reflectance spectra of a typical set of Apollo samples to illustrate spectral character in the mid-infrared (4 to 12 microns) of lunar materials and how the spectra varies among three main forms: soil, breccia, and igneous rocks. Reflectance data, to a close approximation, are the inverse of emission spectra; thus, for a given material the spectral reflectance (R) at any given wavelength is related to emission (E) by 1 - R equals E. Therefore, one can use reflectance spectra of lunar samples to predict how emission spectra of material on the lunar surface will appear to spectrometers on orbiting spacecraft or earthbound telescopes. Spectra were measured in the lab in dry air using a Fourier Transform Infrared spectrometer. Shown here is only the key portion (4 to 12 microns) of each spectrum relating to the principal spectral emission region for sunlit lunar materials and to where the most diagnostic spectral features occur.

  5. Photometric variability of Charon at 2.2 microns

    NASA Technical Reports Server (NTRS)

    Bosh, A. S.; Young, L. A.; Elliot, J. L.; Hammel, H. B.; Baron, R. L.

    1992-01-01

    Pluto-Charon images obtained on each of four nights at 2.2, 1.2, and 1.7 microns are presently fitted by a two-source image model in which the position of Charon and the ratio of its signal to that of Pluto are free parameters. At 2.2 microns, Charon is fainter than Pluto by magnitudes which, when combined with Pluto-Charon system photometry, yield apparent magnitudes of 15.01 + or - 0.08 for Charon at 0.06 lightcurve phase and 15.46 + or - 0.05 at lightcurve phase 0.42. In view of these results, Charon is variable in this filter bypass due to geometric albedo changes as a function of longitude.

  6. Mercury: First Spectra from 8 to 25 Microns Using MIRSI

    NASA Technical Reports Server (NTRS)

    Hanna, K. L. Donaldson; Sprague, A. L.; Kozlowski, R. W. H.

    2005-01-01

    Spectral measurements from 8 to 25 microns of Mercury's surface were taken using MIRSI (Mid-InfraRed Spectrometer and Imager) mounted on the NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii [1]. Few spectral observations of Mercury have been made between 8 and 14 m and these are the first to be made between 17 and 25 m. The goal for these observations is to measure the emission from Mercury in the Restrahllen Bands in the 8 to 25 micron region in an effort to identify spectral features that may give clues to Mercury s composition. These observations will be compared to previous observations [2] [3] [4], and future observations made with instrumentation on Messenger at other spectral regions [5]. Spectra from the Moon were also obtained with the same instrumentation and telescope during the same observing periods.

  7. Tunable diode lasers for 3-30 micron infrared operation

    NASA Technical Reports Server (NTRS)

    Linden, K. J.

    1983-01-01

    The tunable diode laser is now widely used in high resolution infrared spectroscopy studies, taking into account laboratory and industrial applications. The present investigation is concerned with advances related to laser performance and reliability. The advances are the result of improvements in materials and device technologies. Reliability data for broad-area Pb(1-x)Sn(x)Se lasers are considered along with performance improvements in stripe-geometry lasers, laser performance at wavelengths above 25 microns, and laser performance at wavelengths below 4 microns. Attention is given to tunable Pb-salt infrared diode lasers, mesa-stripe geometry lasers of Pb(1-x)Sn(x)Se and PbS(1-x)Se(x), and long wavelength diode laser emission observed in both Pb(1-x)Sn(x)Te and Pb(1-x)Sn(x)Se.

  8. Infrared spectrum of Io, 2.8-5.2 microns

    NASA Astrophysics Data System (ADS)

    Cruikshank, D. P.

    1980-02-01

    The reflectance spectrum of Io is presented from 2.8 to 5.2 microns demonstrating the full extent of the broad and deep spectral absorption between 3.5 and 4.8 microns. Laboratory spectra of nitrates and carbonates diluted with sulfur do not satisfactorily reproduce the Io spectrum, but new information based on recently discovered volcanic activity on the satellite lead to consideration of other classes of compounds reported by Fanale et al. (1979). It is concluded that the variability of the supply of condensible SO2 gas to the surface of Io, its removal by sublimination, and the temporal variations in the strength of the SO2 band may provide an index of volcanic activity on Io that can be monitored from the earth.

  9. Radiation Hard 0.13 Micron CMOS Library at IHP

    NASA Astrophysics Data System (ADS)

    Jagdhold, U.

    2013-08-01

    To support space applications we have developed an 0.13 micron CMOS library which should be radiation hard up to 200 krad. The article describes the concept to come to a radiation hard digital circuit and was introduces in 2010 [1]. By introducing new radiation hard design rules we will minimize IC-level leakage and single event latch-up (SEL). To reduce single event upset (SEU) we add two p-MOS transistors to all flip flops. For reliability reasons we use double contacts in all library elements. The additional rules and the library elements are integrated in our Cadence mixed signal design kit, “Virtuoso” IC6.1 [2]. A test chip is produced with our in house 0.13 micron BiCMOS technology, see Ref. [3]. As next step we will doing radiation tests according the european space agency (ESA) specifications, see Ref. [4], [5].

  10. 60 micron luminosity evolution of rich clusters of galaxies

    SciTech Connect

    Kelly, D.M.; Rieke, G.H. )

    1990-10-01

    The average 60-micron flux has been determined for a collection of optically selected galaxy clusters at redshifts ranging from 0.30 to 0.92. The result, 26 mJy per cluster, represents the faintest flux determination known of using the IRAS data base. The flux from this set of clusters has been compared to the 60-micron flux from a sample of nearby galaxy clusters. It is found that the far-infrared luminosity evolution in cluster galaxies can be no more than a factor of 1.7 from z = 0.4 to the present epoch. This upper limit is close to the evolution predicted for simple aging of the stellar populations. Additional processes such as mergers, cannibalism, or enhanced rates of starbursts appear to occur at a low enough level that they have little influence on the far-infrared emission from clusters over this redshift range. 38 refs.

  11. 60 micron luminosity evolution of rich clusters of galaxies

    NASA Technical Reports Server (NTRS)

    Kelly, Douglas M.; Rieke, George H.

    1990-01-01

    The average 60-micron flux has been determined for a collection of optically selected galaxy clusters at redshifts ranging from 0.30 to 0.92. The result, 26 mJy per cluster, represents the faintest flux determination known of using the IRAS data base. The flux from this set of clusters has been compared to the 60-micron flux from a sample of nearby galaxy clusters. It is found that the far-infrared luminosity evolution in cluster galaxies can be no more than a factor of 1.7 from z = 0.4 to the present epoch. This upper limit is close to the evolution predicted for simple aging of the stellar populations. Additional processes such as mergers, cannibalism, or enhanced rates of starbursts appear to occur at a low enough level that they have little influence on the far-infrared emission from clusters over this redshift range.

  12. Correlation of infrared reflectance ratios at 2.3 microns/1.6 micron and 1.1 micron/1.6 micron with delta O-18 values delineating fossil hydrothermal systems in the Idaho batholith

    NASA Technical Reports Server (NTRS)

    Gillespie, A. R.; Criss, R. E.

    1983-01-01

    Reflectance ratios from laboratory spectra and airborne multispectral images are found to be strongly correlated with delta O-18 values of granite rocks in the Idaho batholith. The correlation is largely a result of interactions between hot water and rock, which lowered the delta O-18 values of the rocks and produced secondary hydrous material. Maps of the ratio of reflectivities at 2.3 and 1.6 microns should delineate fossil hydrothermal systems and provide estimates of alteration intensity. However, hydrous minerals produced during deuteric alteration or weathering cannot be unambiguously distinguished in remotely sensed images from the products of propylitic alteration without the use of narrow-band scanners. The reflectivity at 1.6 micron is strongly correlated with rock density and may be useful in distinguishing rock types in granitic terranes.

  13. The brightness distribution of IRC +10216 at 11 microns

    NASA Technical Reports Server (NTRS)

    Sutton, E. C.; Betz, A. L.; Storey, J. W. V.; Spears, D. L.

    1979-01-01

    The brightness distribution of IRC +10216 at a wavelength of 11 microns was measured in detail using a spatial interferometer. This brightness distribution appears to have azimuthal symmetry; an upper limit of 1.1 may be set to the ellipticity at 11 microns if the object has a major axis oriented either along or perpendicular to the major axis of the optical image. The radial distribution shows both compact and extended emission. The extended component, which is due to thermal emission from circumstellar dust, contributes 91% of the total flux and has a 1/e diameter of 0.90 minutes. The tapered shape of this component is consistent with a l/r squared dust density dependence. The compact component is unresolved (less than 0.2 minutes in diameter) and represents emission from the central star seen through the circumstellar envelope.

  14. Radiation Pressure Measurements on Micron-Size Individual Dust Grains

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Craven, P. D.; Spann, J. F.; Witherow, W. K.; West, E. A.; Gallagher, D. L.; Adrian, M. L.; Fishman, G. J.; Tankosic, D.; LeClair, A.

    2003-01-01

    Measurements of electromagnetic radiation pressure have been made on individual silica (SiO2) particles levitated in an electrodynamic balance. These measurements were made by inserting single charged particles of known diameter in the 0.2- to 6.82-micron range and irradiating them from above with laser radiation focused to beam widths of approximately 175- 400 microns at ambient pressures particle due to the radiation force is balanced by the electrostatic force indicated by the compensating dc potential applied to the balance electrodes, providing a direct measure of the radiation force on the levitated particle. Theoretical calculations of the radiation pressure with a least-squares fit to the measured data yield the radiation pressure efficiencies of the particles, and comparisons with Mie scattering theory calculations provide the imaginary part of the refractive index of SiO2 and the corresponding extinction and scattering efficiencies.

  15. Sub-micron structuring of silicon using femtosecond laser interferometry

    NASA Astrophysics Data System (ADS)

    Oliveira, V.; Vilar, R.; Serra, R.; Oliveira, J. C.; Polushkin, N. I.; Conde, O.

    2013-12-01

    We report the fabrication of planar sub-micron gratings in silicon with a period of 720 nm using a modified Michelson interferometer and femtosecond laser radiation. The gratings consist of alternated stripes of laser ablated and unmodified material. Ablated stripes are bordered by parallel ridges which protrude above the unmodified material. In the regions where ridges are formed, the laser radiation intensity is not sufficient to cause ablation. Nevertheless, melting and a significant temperature increase are expected, and ridges may be formed due to expansion of silicon during resolidification or silicon oxidation. These conclusions are consistent with the evolution of the stripes morphology as a function of the distance from the center of the grating. Sub-micron gratings were created in silicon using femtosecond laser radiation. A modified Michelson interferometer was used. The gratings consist of alternated stripes of ablated and unmodified material. Ablated stripes are surrounded by ridges which protrude above unmodified surface.

  16. Batch Production of Micron-scale Backlighter Targets

    NASA Astrophysics Data System (ADS)

    Arthur, G.

    2016-04-01

    The fabrication of micron-scale backlighter targets is described. Traditionally laser targets have been fabricated using conventional machining or coarse etching processes and have been produced in quantities of 10s to low 100s. The processes described herein allow batch production with numbers in the 1000s. In addition, the Micro-Electro-Mechanical System (MEMS) fabrication techniques used allow much finer tolerances and more accurate placement of the various components relative to each other.

  17. Observations of asteroids in the 3- to 4-micron region

    NASA Technical Reports Server (NTRS)

    Eaton, N.; Green, S. F.; Mccheyne, R. S.; Meadows, A. J.; Veeder, G. J.

    1983-01-01

    Spectra of eleven asteroids (1, 2, 8, 10, 15, 16, 22, 83, 386, 433, 471) have been obtained in the 3- to 4-micron region. Of these, only 1 Ceres and 2 Pallas have previously been observed in this wavelength region. Spectra of the S- and M-type asteroids are generally featureless, but 8 Flora may be an exception. None of the three new C-type spectra show significant absorption.

  18. Development program for 1.93-micron lasers

    NASA Technical Reports Server (NTRS)

    Longeway, P.; Zamerowski, T.; Martinelli, R.; Stolzenberger, R.; Digiuseppe, N.

    1988-01-01

    For the first time lasers operating at 1.93 microns were demonstrated. The lasers were fabricated by Vapor Phase Epitaxial (VPE) growth techniques currently used for the fabrication of high power lasers at 1.3 microns. The structure of these laser diodes consisted of compositionally graded, sulfur-doped InAsP, grown on an InP substrate; a constant-composition n+InAs(0.27)P(0.73) layer, which is the first cladding layer; an In(0.66)Ga(0.34)As layer, which is the active region, and a second InAs(0.27)P(0.73) layer. The devices were oxide-stripe DH lasers (gain-guided only). The best devices had 80 K lasing thresholds in the range of from 80 to 150 mA, and T sub o (below 220 K) in the range of 60 to 90 K. The highest observed temperature of oscillation was 15.5 C. The highest observed power output at 80 K was in the range of 3 to 5 mW. The calculated delta I/delta T was 4.4 A/K. As a part of the materials development, PIN homojunction detectors having the band edge near 1.93 were also fabricated. The best devices (100 micron diameter, mesa structure) exhibited room temperature dark currents in the range of from 20 to 50 nA and had QE at 1.93 microns in the range of 35 to 40 percent. In addition to the device results, the InGaAs-InAsP materials system was extensively investigated and low defect density layers can now be grown allowing for significant device performance improvement.

  19. Two micron pore size MCP-based image intensifiers

    NASA Astrophysics Data System (ADS)

    Glesener, John; Estrera, Joseph

    2010-02-01

    Image intensifiers (I2) have many advantages as detectors. They offer single photon sensitivity in an imaging format, they're light in weight and analog I2 systems can operate for hours on a single AA battery. Their light output is such as to exploit the peak in color sensitivity of the human eye. Until recent developments in CMOS sensors, they also were one of the highest resolution sensors available. The closest all solid state solution, the Texas Instruments Impactron chip, comes in a 1 megapixel format. Depending on the level of integration, an Impactron based system can consume 20 to 40 watts in a system configuration. In further investing in I2 technology, L-3 EOS determined that increasing I2 resolution merited a high priority. Increased I2 resolution offers the system user two desirable options: 1) increased detection and identification ranges while maintaining field-of-view (FOV) or 2) increasing FOV while maintaining the original system resolution. One of the areas where an investment in resolution is being made is in the microchannel plate (MCP). Incorporation of a 2 micron MCP into an image tube has the potential of increasing the system resolution of currently fielded systems. Both inverting and non-inverting configurations are being evaluated. Inverting tubes are being characterized in night vision goggle (NVG) and sights. The non-inverting 2 micron tube is being characterized for high resolution I2CMOS camera applications. Preliminary measurements show an increase in the MTF over a standard 5 micron pore size, 6 micron pitch plate. Current results will be presented.

  20. A 100-micron polarimeter for the Kuiper Airborne Observatory

    SciTech Connect

    Novak, G.; Gonatas, D.P.; Hildebrand, R.H.; Platt, S.R.

    1989-02-01

    Consideration is given to the design and performance of the 100-micron polarimeter proposed for use on the NASA Kuiper Airborne Observatory. The polarimeter specifications are listed. The polarimeter design and data reduction techniques are based on the work of Hildebrand et al. (1984) and Dragovan (1986). The polarimeter has an improved signal-to-noise ratio and systematic measurement errors below 0.2 percent. 20 refs.

  1. A 100-micron polarimeter for the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Novak, G.; Gonatas, D. P.; Hildebrand, R. H.; Platt, S. R.

    1989-01-01

    Consideration is given to the design and performance of the 100-micron polarimeter proposed for use on the NASA Kuiper Airborne Observatory. The polarimeter specifications are listed. The polarimeter design and data reduction techniques are based on the work of Hildebrand et al. (1984) and Dragovan (1986). The polarimeter has an improved signal-to-noise ratio and systematic measurement errors below 0.2 percent.

  2. Mix-and-match lithography for half-micron technology

    NASA Astrophysics Data System (ADS)

    Flack, Warren W.; Dameron, David H.

    1991-08-01

    Half-micron lithography for a production environment is not considered realistic with currently available lithography tools. While optical steppers have high wafer throughputs, they do not have sufficient process latitude at half-micron geometries. In contrast, advanced technologies with sufficient capabilities for half-micron processing such as direct-write e-beam and x-ray lithography are extremely expensive and have low effective throughputs. A mix-and- match lithography approach can take advantage of the best features of both types of systems by sing an optical stepper for noncritical levels and an advanced lithography system for critical levels. In order to facilitate processing of a triple level metal half-micron CMOS technology, a mix-and-match scheme has been developed between a Hitachi HL-700 D e-beam direct write system and an Ultratech 1500 wide-field 1x stepper. The Hitachi is used to pattern an accurate zero or registration level. All critical levels are exposed on the Hitachi and aligned back to this zero level. The Ultratech is used to align all other process levels which do not have critical targets that are placed on subsequent process levels. The mix-and-match approach is discussed, and optical to e-beam as well as e-beam to optical alignment results from seven production lots are presented. The linear alignment error components X translation, Y translation, rotation and magnification are extracted and analyzed to determine their source. It was found that a simple adjustment improved the registration capabilities of these two lithography tools by reducing the X translation, Y translation and rotation standard deviations by a factor of two or more, while greatly reducing the magnification errors between the two tools.

  3. Development of sub-micron patterned carbon electrodes for immunoassays.

    PubMed

    Dontha, N; Nowall, W B; Kuhr, W G

    1999-02-01

    Sub-micron sized domains of a carbon surface are derivatized with antibodies using biotin/avidin technology. These sites are spatially-segregated from, and directly adjacent to, electron transfer sites on the same electrode surface. The distance between these electron transfer sites and enzyme-loaded domains are kept to a minimum (e.g. less than a micron) to maintain the high sensitivity required for the measurement of enzyme-linked cofactors in an enzyme-linked immunoassay (ELISA). This is accomplished through the use of photolithographic attachment of photobiotin using an interference pattern from a UV laser generated at the electrode surface. This allows the construction of microscopic arrays of active ELISA sites on a carbon substrate while leaving other sites underivatized to facilitate electron transfer reactions of redox mediators; thus maximizing sensitivity and detection of the enzyme mediator. The carbon electrode surface is characterized with respect to its chemical structure and electron transfer properties following each step of the antibody immobilization process. The characterization of specific modifications of micron regions of the carbon surface requires analytical methodology that has both high spatial resolution and sensitivity. We have used fluorescence microscopy with a cooled CCD imaging system to visualize the spatial distribution of enzyme immobilization sites (indicated by fluorescence from Texas-Red labeled antibody) across the carbon surface. The viability of the enzyme attached to the surface in this manner was demonstrated by imaging the distribution of an insoluble, fluorescent product. PMID:10698570

  4. A model for the CI (609 micron) emission of Orion

    NASA Technical Reports Server (NTRS)

    Tielens, A. G. G. M.; Hollenbach, D.

    1985-01-01

    A numerical model energy balance and chemical equilibrium in the photodissociation regions at the edge of molecular clouds is presented. The model is used to calculate the emergent intensities of the following fine-structure lines: OI (at 63, 145 microns); CI (at 609, 370 microns); C II (at 158 microns); and the low-lying rotational transitions of CO. It is shown that column densities in the range 2 x 10 to the 17th to 2 x 10 to the 18th per sq cm can be obtained for the C(+)/C/CO transition region at the edges of molecular clouds. The difference in the column densities is attributed to changes in the charge exchange reactions of C(+) with SiO and S, and to the process of carbon self-healing. It is found that the calculations are in good agreement with the observed conditions in the photodissociation regions behind Orion (1) C Ori, and near the surface of OMC 1.

  5. Effect of humidity on aerosolization of micronized drugs.

    PubMed

    Young, Paul M; Price, Robert; Tobyn, Michael J; Buttrum, Mark; Dey, Fiona

    2003-10-01

    The variation of aerosolization with humidity for three micronized drugs used in the treatment of asthma was evaluated by using in vitro methods. Micronized samples of disodium cromoglycate (DSCG), salbutamol sulphate, and triamcinolone acetonide (TAA) were stored for 12hr at 15, 30, 45, 60, and 75% relative humidity (RH). A suitable "reservoir" dry powder inhaler was loaded and tested by using a twin-stage impinger at each specific humidity. The aerosolization efficiency of all three micronized drugs was affected by variations in humidity. The percentage of the delivered dose and the fine particle fraction of the loaded dose (FPFLD) for both DSCG and salbutamol sulphate decreased with increasing humidity; with the largest decrease in FPFLD occurring between 45% and 60% RH for DSCG and 60% to 75% RH for salbutamol sulphate. These observations suggest that the adhesion properties for both DSCG and salbutamol sulphate, which govern the aerosolization efficiency, are predominately influenced by capillary interactions. In contrast, the FPFLD for TAA significantly increased as the humidity increased over the range 15% to 75% RH, suggesting that triboelectric forces predominate particle-particle interactions. These variations in drug particulate behavior highlight the importance of an individual formulation approach when developing dry powder inhalation systems. PMID:14606660

  6. Measuring micron size beams in the SLC final focus

    SciTech Connect

    McCormick, D.; Ross, M.; DeBarger, S.

    1994-10-01

    A pair of high resolution wire scanners have been built and installed in the SLC final focus. The final focus optics uses a set of de-magnifying telescopes, and an ideal location for a beam size monitor is at one of the magnified image points of the interaction point. The image point chosen for these scanners is in the middle of a large bend magnet. The design beam spots here are about 2 microns in the vertical and 20 microns in the horizontal plane. The scanners presented a number of design challenges. In this paper we discuss the mechanical design of the scanner, and fabrication techniques of its ceramic wire support card which holds many 4 and 7 um carbon wires. Accurate motion of the wire during a scan is critical. In this paper we describe tests of stepper motors, gear combinations, and radiation hardened encoders needed to produce the required motion with a step resolution of 80 nanometers. Also presented here are the results of scattered radiation detector placement studies carried out to optimize the signal from the 4 micron wires. Finally, we present measurements from the scanner.

  7. Radiation Pressure Measurements on Micron Size Individual Dust Grains

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Craven, P.D.; Spann, J. F.; Tankosic, D.; Witherow, W. K.; LeClair, A.; West, E.; Sheldon, R.; Gallagher, D. L.; Adrian, M. L.

    2003-01-01

    Measurements of electromagnetic radiation pressure have been made on individual silica (SiO2) particles levitated in an electrodynamic balance. These measurements were made by inserting single charged particles of known diameter in the 0.2 micron to 6.82 micron range and irradiating them from above with laser radiation focused to beam-widths of approx. 175-400 micron, at ambient pressures approx. 10(exp -3) to 10(exp -4) torr. The downward displacement of the particle due to the radiation force is balanced by the electrostatic force indicated by the compensating dc potential applied to the balance electrodes, providing a direct measure of the radiation force on the levitated particle. Theoretical calculations of the radiation pressure with a least-squares fit to the measured data yield the radiation pressure efficiencies of the particles, and comparisons with Mie scattering theory calculations provide the imaginary part of the refractive index of silica and the corresponding extinction and scattering efficiencies.

  8. 2.2-micron field stars at the North Galactic Pole

    NASA Technical Reports Server (NTRS)

    Elias, J. H.

    1978-01-01

    The properties of the 2.2-micron field stars seen near the North Galactic Pole by the Two Micron Sky Survey and by surveys at higher sensitivity are discussed. All the 2.2-micron sources found in these surveys can be identified with stars with known spectral types. The distribution of the 2.2-micron field stars appears to be well-understood.

  9. Photon Counting Detectors for the 1.0 - 2.0 Micron Wavelength Range

    NASA Technical Reports Server (NTRS)

    Krainak, Michael A.

    2004-01-01

    We describe results on the development of greater than 200 micron diameter, single-element photon-counting detectors for the 1-2 micron wavelength range. The technical goals include quantum efficiency in the range 10-70%; detector diameter greater than 200 microns; dark count rate below 100 kilo counts-per-second (cps), and maximum count rate above 10 Mcps.

  10. A High Energy 2-microns Laser for Multiple Lidar Applications

    NASA Technical Reports Server (NTRS)

    Yu, Jirong; Singh, Upendra N.; Barnes, James C.; Barnes, Norman P.; Petros, Mulugeta

    2000-01-01

    Solid-state 2-microns laser has been receiving considerable interest because of its eye-safe property and efficient diode pump operation, It has potential for multiple lidar applications to detect water vapor. carbon dioxide and winds. In this paper, we describe a 2-microns double pulsed Ho:Tm:YLF laser and end-pumped amplifier system. A comprehensive theoretical model has been developed to aid the design and optimization of the laser performance. In a single Q-switched pulse operation the residual energy stored in the Tm atoms will be wasted. However, in a double pulses operation mode, the residual energy stored in the Tm atoms will repopulate the Ho atoms that were depleted by the extraction of the first Q-switched pulse. Thus. the Tin sensitized Ho:YLF laser provides a unique advantage in applications that require double pulse operation, such as Differential Absorption Lidar (DIAL). A total output energy of 146 mJ per pulse pair under Q-switch operation is achieved with as high as 4.8% optical to optical efficiency. Compared to a single pulse laser, 70% higher laser efficiency is realized. To obtain high energy while maintaining the high beam quality, a master-oscillator-power-amplifier 2-microns system is designed. We developed an end-pumped Ho:Tm:YLF disk amplifier. This amplifier uses two diode arrays as pump source. A non-imaging lens duct is used to couple the radiation from the laser diode arrays to the laser disk. Preliminary result shows that the efficiency of this laser can be as high as 3%, a factor of three increases over side-pump configuration. This high energy, highly efficient and high beam quality laser is a promising candidate for use in an efficient, multiple lidar applications.

  11. The brightest high-latitude 12-micron IRAS sources

    NASA Technical Reports Server (NTRS)

    Hacking, P.; Beichman, C.; Chester, T.; Neugebauer, G.; Emerson, J.

    1985-01-01

    The Infrared Astronomical Satellite (IRAS) Point Source catalog was searched for sources brighter than 28 Jy (0 mag) at 12 microns with absolute galactic latitude greater than 30 deg excluding the Large Magellanic Cloud. The search resulted in 269 sources, two of which are the galaxies NGC 1068 and M82. The remaining 267 sources are identified with, or have infrared color indices consistent with late-type stars some of which show evidence of circumstellar dust shells. Seven sources are previously uncataloged stars. K and M stars without circumstellar dust shells, M stars with circumstellar dust shells, and carbon stars occupy well-defined regions of infrared color-color diagrams.

  12. A two micron polarization survey of T Tauri stars

    SciTech Connect

    Tamura, M.; Sato, S. Massachusetts Univ., Amherst National Astronomical Observatory, Mitaka )

    1989-10-01

    Results are presented of a K-band (2.2 microns) polarization survey of 39 T Tauri stars (TTSs) and, in addition, of eight other young stellar objects and 11 background field stars in the Taurus-Auriga dark cloud complex. It was found that about 60 percent of the TTSs are linearly polarized, but with relatively small degrees of polarization up to about 3 percent. A comparison of the results of this survey with those of the IR polarization survey of the low-luminosity IRAS sources in the same region suggests an evolutionary sequence in the IR polarization of young stellar objects. 79 refs.

  13. A Two Micron Coherent Differential Absorption Lidar Development

    NASA Technical Reports Server (NTRS)

    Yu, Jirong; Petros, Mulugeta; Chen, Songsheng; Bai, Yingxin; Petzar, Paul J.; Trieu, Bo C.; Koch, Grady J.; Beyon, Jeffrey Y.; VanValkenburg, Randal L.; Kavaya, Michael J.; Singh, Upendra N.

    2010-01-01

    A pulsed, 2-micron coherent Differential Absorption Lidar (DIAL)/Integrated Path Differential Absorption (IPDA) transceiver, developed under the Laser Risk Reduction Program (LRRP) at NASA, is integrated into a fully functional lidar instrument. This instrument measures atmospheric CO2 profiles (by DIAL) from a ground platform. It allows the investigators to pursue subsequent in science-driven deployments, and provides a unique tool for Active Sensing of CO2 Emissions over Night, Days, and Seasons (ASCENDS) validation that was strongly advocated in the recent ASCENDS Workshop. Keywords: Differential Absorption Lidar, Near Infrared Laser,

  14. Liquid crystal alignment induced by micron-scale patterned surfaces.

    PubMed

    Willman, E; Seddon, L; Osman, M; Bulak, A; James, R; Day, S E; Fernandez, F A

    2014-05-01

    Induced bulk orientation of nematic liquid crystal in contact with micron-scale patterned surfaces is investigated using the Landau-de Gennes theory by means of three-dimensional simulations. The effect of the size and spacing of square cross-sectional well and post patterns is investigated and shown to influence the orientation of the liquid crystal bulk, far removed from the surface. Additionally, the effective anchoring strength of the induced alignment is estimated using a modified version of the torque balance method. Both azimuthal and zenithal multistability are shown to exist within unique ranges of feature sizes. PMID:25353809

  15. Fabrication of Micron Scale Retroreflectors for Novel Biosensors

    NASA Astrophysics Data System (ADS)

    Sherlock, Tim

    Many bioanalytical and diagnostic methods detect the presence of secondary labels, such as colored particles, fluorescent molecules, nanoparticles, and enzyme reaction product, when they accumulate in the presence of the target biomolecules (i.e., bacteria, viruses, etc.) at predetermined locations. In this dissertation, we describe the development of a new class of labels consisting of micro-fabricated retroreflectors that are easy to image, compatible with machine vision automation, and can be detected in solution or within microfluidic channels. The retroreflecting structures are designed to return incident light directly back to its source over a large range of angles, making them extremely detectable using low cost, low numerical aperture objectives, as is evidenced by their common use as lane markers and in safety signs. This work describes two different biosensing systems using these labels. In the first, retroreflectors are fabricated at fixed locations at the base of microfluidic channels and their brightness is attenuated by the biologically-driven accumulation of magnetic particles, thus forming a readout strategy that well-suited for automation and multiplexing. The work demonstrates that single, micron-scale magnetic beads can be rapidly detected over very large areas (square millimeters). The second approach uses suspended corner cube retroreflectors, five microns on a side, as ultra bright labels that are bound to magnetic sample preparation beads in the presence of an analyte. The magnetic particles can then be moved to an imaging site within the sample where the cubes are readily detected. The fabrication of these micron-scale retroreflectors required the development of new lithography, thin film disposition, and reactive ion etching tools and the integration of chip-based structures with microfluidic systems. The dissertation also describes the experimental validation of a Fourier optics model that accounts for diffraction inherent to the micron

  16. Advanced composite applications for sub-micron biologically derived microstructures

    NASA Technical Reports Server (NTRS)

    Schnur, J. M.; Price, R. R.; Schoen, P. E.; Bonanventura, Joseph; Kirkpatrick, Douglas

    1991-01-01

    A major thrust of advanced material development is in the area of self-assembled ultra-fine particulate based composites (micro-composites). The application of biologically derived, self-assembled microstructures to form advanced composite materials is discussed. Hollow 0.5 micron diameter cylindrical shaped microcylinders self-assemble from diacetylenic lipids. These microstructures have a multiplicity of potential applications in the material sciences. Exploratory development is proceeding in application areas such as controlled release for drug delivery, wound repair, and biofouling as well as composites for electronic and magnetic applications, and high power microwave cathodes.

  17. WISE 3.4 micron Detection of PTF10acbp

    NASA Astrophysics Data System (ADS)

    Cutri, R. M.; Hoffman, D.; Masci, F.; Conrow, T.; Kasliwal, M. M.; Helou, G.; Ofek, E. O.; Kulkarni, S. R.; Surace, J.

    2011-01-01

    The Wide-field Infrared Survey Explorer (WISE; Wright et al. 2010 AJ 140, 1868) scanned the position of PTF10acbp (ATEL #3094), the luminous red nova in the spiral galaxy UGC 11973, 23 times between 2010 June 17 and June 23, and again 30 times between 2010 December 12 and December 16, just five days after the transient's discovery. The June observations were made during the WISE cryogenic survey yielding images at 3.4, 4.6, 12 and 22 microns.

  18. Sub-micron texturing of silicon wafer with fiber laser

    NASA Astrophysics Data System (ADS)

    Farrokhi, Hamid; Zhou, Wei; Zheng, Hong Yu; Li, Zhongli

    2011-03-01

    Laser texturing is extensively investigated for modifying surface properties. A continuous wave (CW) fiber laser (λ= 1090nm) was used to pattern a silicon wafer surface in ambient and O2 atmosphere respectively. The O2 gas stream was delivered through a coaxial nozzle to the laser spot. Characterization of the patterned features was carried out by surface profiling, scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS or EDX), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Formation of laser-induced silicon oxide sub-micron bumps was observed, which were analyzed and shown to cause changes in surface wetability and reflectivity.

  19. Micron-scale lens array having diffracting structures

    DOEpatents

    Goldberg, Kenneth A

    2013-10-29

    A novel micron-scale lens, a microlens, is engineered to concentrate light efficiently onto an area of interest, such as a small, light-sensitive detector element in an integrated electronic device. Existing microlens designs imitate the form of large-scale lenses and are less effective at small sizes. The microlenses described herein have been designed to accommodate diffraction effects, which dominate the behavior of light at small length scales. Thus a new class of light-concentrating optical elements with much higher relative performance has been created. Furthermore, the new designs are much easier to fabricate than previous designs.

  20. Micron: an Actively Stabilized Handheld Tool for Microsurgery

    PubMed Central

    MacLachlan, Robert A.; Becker, Brian C.; Tabarés, Jaime Cuevas; Podnar, Gregg W.; Lobes, Louis A.; Riviere, Cameron N.

    2011-01-01

    We describe the design and performance of a hand-held actively stabilized tool to increase accuracy in micro-surgery or other precision manipulation. It removes involuntary motion such as tremor by actuating the tip to counteract the effect of the undesired handle motion. The key components are a three-degree-of-freedom piezoelectric manipulator that has 400 μm range of motion, 1 N force capability, and bandwidth over 100 Hz, and an optical position measurement subsystem that acquires the tool pose with 4 μm resolution at 2000 samples/s. A control system using these components attenuates hand motion by at least 15 dB (a fivefold reduction). By considering the effect of the frequency response of Micron on the human visual feedback loop, we have developed a filter that reduces unintentional motion, yet preserves intuitive eye-hand coordination. We evaluated the effectiveness of Micron by measuring the accuracy of the human/machine system in three simple manipulation tasks. Handheld testing by three eye surgeons and three non-surgeons showed a reduction in position error of between 32% and 52%, depending on the error metric. PMID:23028266

  1. VTT's micron-scale silicon rib+strip waveguide platform

    NASA Astrophysics Data System (ADS)

    Aalto, Timo; Harjanne, Mikko; Cherchi, Matteo

    2016-05-01

    Silicon rib waveguides enable single-mode (SM) operation even with the combination of multi-micron core dimensions and high refractive index contrast. In such large waveguides the optical mode field is almost completely confined inside the Si core, which leads to small propagation losses and small polarization dependency. The unique SM condition of the rib waveguide also enables the use of an ultra-wide wavelength range, for example from 1.2 to <1.7 μm, without sacrificing either SM operation or low propagation loss. This makes micron-scale Si waveguides particularly well-suited for spectroscopy and extensive wavelength division multiplexing. However, rib waveguides require large bending radii, which lead to large circuit sizes. There are two solutions for this. So-called Euler bends in Si strip waveguides enable low-loss bends down to 1 μm bending radius with less than 0.1 dB/90° loss for both polarizations. Another alternative is a total-internal reflection mirror that can have loss as low as 0.1 dB for both polarizations in either strip or rib waveguides. The excitation of higher order modes in large strip waveguides is avoided by using adiabatic rib-strip converters and low-loss components. With rib and strip waveguides it is possible to reach a unique combination of low loss, extremely small footprint, small polarization dependency, ultra-wide bandwidth and tolerance to high optical powers.

  2. Influence of micronization on improving phytoestrogenic effects of wheat bran.

    PubMed

    Yang, Jinghui; Wu, Qinyan; Chen, Hongzhou; Zhuang, Yiqing

    2015-01-01

    The influence of micronization on improving the phytoestrogenic effects of wheat bran was studied. Wheat bran samples were prepared by ball milling, and an animal experiment was carried out by feeding 8-month-old female rats wheat bran. The effect of wheat bran samples on serum estradiol (E2) and progesterone (P) levels of female 8-month-old rats was investigated. The wheat bran with a median diameter of 392.1 μm was micronized to 91.1 and 9.7 μm in median diameter by dry milling and wet milling for 5 hours, respectively. Microscopic observation and X-ray diffraction revealed more potential damage from wet milling than dry milling on the crystal structure of wheat bran granules. Almost all particles were dissolved and there was no obvious crystal peak in the 5-hour wet-milled wheat bran. The serum E2 and P levels of the 8-month-old rats fed wet-milled bran were increased significantly, 2.2 times higher than that of the same aged control group. The experimental results indicated that wet milling could destroy the crystal structure of wheat bran granules and improve the phytoestrogenic effects of wheat bran. PMID:25757396

  3. THUMPER - A 200-Micron Camera for the JCMT

    NASA Astrophysics Data System (ADS)

    Evans, Rhodri; Ward-Thompson, Derek; Ade, Peter; Gear, Walter; Griffin, Matt; Leeks, Sarah; Walker, Richard

    We are building a Two HUndred Micron PhotometER (THUMPER) for the 15-m James Clerk Maxwell Telescope in Hawaii. Taking advantage of a narrow atmospheric window that opens up at this wavelength on high, dry sites, THUMPER will make continuum observations at 200-microns from the ground with unprecedented 7-arcsecond angular resolution. The focal plane comprises a hexagonal close-packed array of seven stressed Ge:Ga photoconductors fed by individual Winston cones and operating at 3.7K. The detectors are read out by TIA amplifiers using cold JFET pairs. THUMPER is being designed to work in parallel with SCUBA using a dichroic beam-splitter. The data will be handled by the SCUBA data acquisition system, enabling all SCUBA users to see the THUMPER instrument as an additional shortwavelength sub-mm array. The instrument is planned to be in operation by early 2003. The predicted NEFD under good conditions (0.5mm of pwv) is around 20 Jy/Hz1/2.

  4. Chip-on-flex with 5-micron features

    NASA Astrophysics Data System (ADS)

    Salmon, Peter C.

    2003-01-01

    A new module packaging method is proposed for electronic systems comprising a motherboard and integrated circuit (IC) chips. Pitches of 10 microns for conductive traces, and 100 microns for bonding pads are achievable. The enabling technology is glass panel manufacture, using equipment and techniques similar to those employed for fabricating liquid crystal display (LCD) panels. Flexible circuits are produced on a glass carrier using a release layer, and the carrier is removed after most of the processing is complete. IC chips are stud bumped and flip chip bonded to wells filled with solder, provided on the flexible circuit. The fabrication density achievable with wafer level packaging (WLP) using silicon wafers is substantially more than is needed for module packaging, as described herein. It is possible to provide WLP performance on glass at a much lower cost. The conductor features on glass are fine enough for the most demanding packaging and assembly techniques. The lowered cost of glass applies to the interconnection circuit plus assembly, test and rework. A test method called Tester-On-Board (TOB) is proposed, employing special-purpose test chips that are directly mounted in the system and mimic the capabilities of external testers. Methods for hermetic sealing, electromagnetic screening, and high-density off-board connections are also proposed.

  5. Chemically generated convective transport of micron sized particles

    NASA Astrophysics Data System (ADS)

    Shklyaev, Oleg; Das, Sambeeta; Altemose, Alicia; Shum, Henry; Balazs, Anna; Sen, Ayusman

    2015-11-01

    A variety of chemical and biological applications require manipulation of micron sized objects like cells, viruses, and large molecules. Increasing the size of particles up to a micron reduces performance of techniques based on diffusive transport. Directional transport of cargo toward detecting elements reduces the delivery time and improves performance of sensing devices. We demonstrate how chemical reactions can be used to organize fluid flows carrying particles toward the assigned destinations. Convection is driven by density variations caused by a chemical reaction occurring at a catalyst or enzyme-covered target site. If the reaction causes a reduction in fluid density, as in the case of catalytic decomposition of hydrogen peroxide, then fluid and suspended cargo is drawn toward the target along the bottom surface. The intensity of the fluid flow and the time of cargo delivery are controlled by the amount of reagent in the system. After the reagent has been consumed, the fluid pump stops and particles are found aggregated on and around the enzyme-coated patch. The pumps are reusable, being reactivated upon injection of additional reagent. The developed technique can be implemented in lab-on-a-chip devices for transportation of micro-scale object immersed in solution.

  6. Comparative investigations of the effects of the neodymium:YAG laser at 1. 06 microns and 1. 32 microns on tissue

    SciTech Connect

    Frank, F.; Beck, O.J.; Hessel, S.; Keiditsch, E.

    1987-01-01

    The beneficial deep homogeneous coagulation of neodymium (Nd):YAG laser radiation at 1.06 microns owing to low absorption and high scattering in tissue has been documented widely. For another Nd:YAG laser wavelength at 1.32 microns the absorption coefficient of water and saline is approximately ten times higher than at 1.06 microns. This results in more efficient energy conversion into heat in tissue at 1.32 microns. The extinction coefficient in blood at 1.32 microns is only one-third of that at 1.06 microns. We would expect this to result in less heat dissipation by blood and deeper penetration in tissue at 1.32 microns. Nevertheless, at this wavelength scattering also contributes to an effective, uniform distribution of the laser light in the tissue. Animal experiments have been done to examine the effect of wavelength, irradiation time, and beam geometry on tissue damage and to assess its possible clinical uses. The results imply that the 1.32 microns wavelength will produce further indications for the use of the Nd:YAG laser in surgery.

  7. Two Color Interferometry with Nonlinear Refractive Properties

    NASA Technical Reports Server (NTRS)

    Vikram, Chandra S.; Witherow, William K.

    2002-01-01

    Using nonlinear refractive properties of salt-water solution at two wavelengths, numerical analysis has been performed to extract temperature and concentration from virtual interferometric fringe data. The theoretical study, using a commercially available equation solving tool, starts with critical fringe counting needs and the role of nonlinear refractive properties in such measurements. Finally, methodology of the analysis, developed codes, and fringe counting accuracy needs are described in detail.

  8. Discovering sub-micron ice particles across Dione' surface

    NASA Astrophysics Data System (ADS)

    Scipioni, Francesca; Schenk, Pual; Tosi, Federico; Clark, Roger; Dalle Ore, Cristina; Combe, Jean-Philippe

    2015-11-01

    Water ice is the most abundant component of Saturn’s mid-sized moons. However, these moons show an albedo asymmetry - their leading sides are bright while their trailing side exhibits dark terrains. Such differences arise from two surface alteration processes: (i) the bombardment of charged particles from the interplanetary medium and driven by Saturn’s magnetosphere on the trailing side, and (ii) the impact of E-ring water ice particles on the satellites’ leading side. As a result, the trailing hemisphere appears to be darker than the leading side. This effect is particularly evident on Dione's surface. A consequence of these surface alteration processes is the formation or the implantation of sub-micron sized ice particles.The presence of such particles influences and modifies the surfaces' spectrum because of Rayleigh scattering by the particles. In the near infrared range of the spectrum, the main sub-micron ice grains spectral indicators are: (i) asymmetry and (ii) long ward minimum shift of the absorption band at 2.02 μm (iii) a decrease in the ratio between the band depths at 1.50 and 2.02 μm (iv) a decrease in the height of the spectral peak at 2.6 μm (v) the suppression of the Fresnel reflection peak at 3.1 μm and (vi) the decrease of the reflection peak at 5 μm relative to those at 3.6 μm.We present results from our ongoing work mapping the variation of sub-micron ice grains spectral indicators across Dione' surface using Cassini-VIMS cubes acquired in the IR range (0.8-5.1 μm). To characterize the global variations of spectral indicators across Dione' surface, we divided it into a 1°x1° grid and then averaged the band depths and peak values inside each square cell.We will investigate if there exist a correspondence with water ice abundance variations by producing water ice' absorption band depths at 1.25, 1.52 and 2.02 μm, and with surface morphology by comparing the results with ISS color maps in the ultraviolet, visible and infrared

  9. The 2-micron plasmid as a nonselectable, stable, high copy number yeast vector

    NASA Technical Reports Server (NTRS)

    Ludwig, D. L.; Bruschi, C. V.

    1991-01-01

    The endogenous 2-microns plasmid of Saccharomyces cerevisiae has been used extensively for the construction of yeast cloning and expression plasmids because it is a native yeast plasmid that is able to be maintained stably in cells at high copy number. Almost invariably, these plasmid constructs, containing some or all 2-microns sequences, exhibit copy number levels lower than 2-microns and are maintained stably only under selective conditions. We were interested in determining if there was a means by which 2-microns could be utilized for vector construction, without forfeiting either copy number or nonselective stability. We identified sites in the 2-microns plasmid that could be used for the insertion of genetic sequences without disrupting 2-microns coding elements and then assessed subsequent plasmid constructs for stability and copy number in vivo. We demonstrate the utility of a previously described 2-microns recombination chimera, pBH-2L, for the manipulation and transformation of 2-microns as a pure yeast plasmid vector. We show that the HpaI site near the STB element in the 2-microns plasmid can be utilized to clone yeast DNA of at least 3.9 kb with no loss of plasmid stability. Additionally, the copy number of these constructs is as high as levels reported for the endogenous 2-microns.

  10. The 1.083 micron tunable CW semiconductor laser

    NASA Technical Reports Server (NTRS)

    Wang, C. S.; Chen, Jan-Shin; Lu, Ken-Gen; Ouyang, Keng

    1991-01-01

    A tunable CW laser is desired to produce light equivalent to the helium spectral line at 1.08 microns. This laser will serve as an optical pumping source for He-3 and He-4 atoms used in space magnetometers. This light source can be fabricated either as a semiconductor laser diode or a pumped solid state laser. Continuous output power of greater than 10 mW is desired. Semiconductor lasers can be thermally tuned, but must be capable of locking onto the helium resonance lines. Solid state lasers must have efficient pumping sources suitable for space configuration. Additional requirements are as follows: space magnetometer applications will include low mass (less than 0.5 kg), low power consumption (less than 0.75 W), and high stability/reliability for long missions (5-10 years).

  11. Mars Atmospheric Characterization Using Advanced 2-Micron Orbiting Lidar

    NASA Technical Reports Server (NTRS)

    Singh, U.; Engelund, W.; Refaat, T.; Kavaya, M.; Yu, J.; Petros, M.

    2015-01-01

    Mars atmospheric characterization is critical for exploring the planet. Future Mars missions require landing massive payloads to the surface with high accuracy. The accuracy of entry, descent and landing (EDL) of a payload is a major technical challenge for future Mars missions. Mars EDL depends on atmospheric conditions such as density, wind and dust as well as surface topography. A Mars orbiting 2-micron lidar system is presented in this paper. This advanced lidar is capable of measuring atmospheric pressure and temperature profiles using the most abundant atmospheric carbon dioxide (CO2) on Mars. In addition Martian winds and surface altimetry can be mapped, independent of background radiation or geographical location. This orbiting lidar is a valuable tool for developing EDL models for future Mars missions.

  12. Coherent Spin Transport through a 350Micron Thick Silicon Wafer

    NASA Astrophysics Data System (ADS)

    Huang, Biqin; Monsma, Douwe J.; Appelbaum, Ian

    2007-10-01

    We use all-electrical methods to inject, transport, and detect spin-polarized electrons vertically through a 350-micron-thick undoped single-crystal silicon wafer. Spin precession measurements in a perpendicular magnetic field at different accelerating electric fields reveal high spin coherence with at least 13π precession angles. The magnetic-field spacing of precession extrema are used to determine the injector-to-detector electron transit time. These transit time values are associated with output magnetocurrent changes (from in-plane spin-valve measurements), which are proportional to final spin polarization. Fitting the results to a simple exponential spin-decay model yields a conduction electron spin lifetime (T1) lower bound in silicon of over 500 ns at 60 K.

  13. Two Micron Laser Technology Advancements at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.

    2010-01-01

    An Independent Laser Review Panel set up to examine NASA s space-based lidar missions and the technology readiness of lasers appropriate for space-based lidars indicated a critical need for an integrated research and development strategy to move laser transmitter technology from low technical readiness levels to the higher levels required for space missions. Based on the review, a multiyear Laser Risk Reduction Program (LRRP) was initiated by NASA in 2002 to develop technologies that ensure the successful development of the broad range of lidar missions envisioned by NASA. This presentation will provide an overview of the development of pulsed 2-micron solid-state laser technologies at NASA Langley Research Center for enabling space-based measurement of wind and carbon dioxide.

  14. The 2 micron plasmid purloins the yeast cohesin complex

    PubMed Central

    Mehta, Shwetal; Yang, Xian Mei; Chan, Clarence S.; Dobson, Melanie J.; Jayaram, Makkuni; Velmurugan, Soundarapandian

    2002-01-01

    The yeast 2 micron plasmid achieves high fidelity segregation by coupling its partitioning pathway to that of the chromosomes. Mutations affecting distinct steps of chromosome segregation cause the plasmid to missegregate in tandem with the chromosomes. In the absence of the plasmid stability system, consisting of the Rep1 and Rep2 proteins and the STB DNA, plasmid and chromosome segregations are uncoupled. The Rep proteins, acting in concert, recruit the yeast cohesin complex to the STB locus. The periodicity of cohesin association and dissociation is nearly identical for the plasmid and the chromosomes. The timely disassembly of cohesin is a prerequisite for plasmid segregation. Cohesin-mediated pairing and unpairing likely provides a counting mechanism for evenly partitioning plasmids either in association with or independently of the chromosomes. PMID:12177044

  15. A doublet microlens array for imaging micron-sized objects

    PubMed Central

    Tripathi, A; Chronis, N

    2011-01-01

    We present a high-numerical aperture, doublet microlens array for imaging micron-sized objects. The proposed doublet architecture consists of glass microspheres trapped on a predefined array of silicon microholes and covered with a thin polymer layer. A standard silicon microfabrication process and a novel fluidic assembly technique were combined to obtain an array of 56 μm diameter microlenses with a numerical aperture of ~0.5. Using such an array, we demonstrated brightfield and fluorescent image formation of objects directly on a CCD sensor without the use of intermediate lenses. The proposed technology is a significant advancement toward the unmet need of inexpensive, miniaturized optical modules which can be further integrated with lab-on-chip microfluidic devices and photonic chips for a variety of high-end imaging/detection applications. PMID:22003271

  16. [EXPERIENCE IN TREATING HELMINTHISM WITH MICRONIZED ALBENDAZOLE (GELMODOL)].

    PubMed

    Zavoikin, V D; Tumolskaya, N I; Mazmanyan, M V; Zelya, O P; Tikhonova, D V

    2015-01-01

    The paper gives the results of treatment with micronized albendazole (Gelmodol-BM, World Medicine, UK) in 87 patients of the Department of Medical Parasitology and Tropical Diseases, Clinical and Diagnostic Center, Clinical Center, I.M.Sechenov First Moscow State Medical University. Thirty-two patients with echinococcosis 8 with alveococcosis (including 4 inoperable patients), 10 with ascariasis, 10 with toxocariasis, 15 with enterobiasis, and 12 people diagnosed with larva migrans were treated in 2013-2014. The drug's routine doses and dosage regimens were used. Albendazole (Gelmodol, World Medicine, UK) showed a high efficacy with good tolerability, which is highly competitive with that of the drugs manufactured by IPCA Laboratories Ltd., India (such as nemozole). Both medicaments above-mentioned may be successfully used in the treatment of many helminthisms. PMID:26827590

  17. Predicting fracture in micron-scale polycrystalline silicon MEMS structures.

    SciTech Connect

    Hazra, Siddharth S.; de Boer, Maarten Pieter; Boyce, Brad Lee; Ohlhausen, James Anthony; Foulk, James W., III; Reedy, Earl David, Jr.

    2010-09-01

    Designing reliable MEMS structures presents numerous challenges. Polycrystalline silicon fractures in a brittle manner with considerable variability in measured strength. Furthermore, it is not clear how to use a measured tensile strength distribution to predict the strength of a complex MEMS structure. To address such issues, two recently developed high throughput MEMS tensile test techniques have been used to measure strength distribution tails. The measured tensile strength distributions enable the definition of a threshold strength as well as an inferred maximum flaw size. The nature of strength-controlling flaws has been identified and sources of the observed variation in strength investigated. A double edge-notched specimen geometry was also tested to study the effect of a severe, micron-scale stress concentration on the measured strength distribution. Strength-based, Weibull-based, and fracture mechanics-based failure analyses were performed and compared with the experimental results.

  18. Radiation Hard 0.25 Micron CMOS Library at IHP

    NASA Astrophysics Data System (ADS)

    Jagdhold, U.

    2008-08-01

    To support space applications we have produced a test chip with our in house 0.25 micron BiCMOS- Technology. Then the chips were radiated and measured. During measurements no threshold voltage shift and no single event latchup (SEL) were obtained up to a level of 200 krad. As conclusion of the measurement we developed new radiation hard design rules and according to these rules we created a new radiation hard CMOS library. With this new library we produced a Leon3 chip with triple module redundancy. Single event upsets did occur. Therefore we upgrade the library to make the flip flops more resistant against single event upset (SEU) by adding two p-MOS transistors.

  19. 8- to 13-micron spectroscopy of Comet Levy 1990 XX

    NASA Technical Reports Server (NTRS)

    Lynch, David K.; Russell, Ray W.; Hackwell, John A.; Hanner, Martha S.; Hammel, Heidi B.

    1992-01-01

    The results are reported of IR spectroscopy of Comet Levy 1990 XX over a three-day period when the comet was about 1.54 AU from the sun roughly 70 days before perihelion. Comet Levy 1990 XX was bright, and for at least part of its inbound journey toward perihelion, active. At a distance of 1.54 AU from the sun it showed strong structured silicate emission with peaks or shoulders at 9.8 and 11.2 microns. These features resemble those of Comets P/Halley and Bradfield 1987 XXIX. The comet was variable in brightness. Specifically, the contrast of the silicate features changed by a factor of two relative to the continuum level and showed some evidence for a shape change as well.

  20. Programmable, directed assembly of micron-scale components

    NASA Astrophysics Data System (ADS)

    Floryan, Caspar; Westervelt, Robert

    2011-03-01

    Self assembly is a nascent paradigm for assembling components in the micron to millimeter size range. Such assemblies are often performed by modifying the surface chemistries of the individual components or by creating flow fields directing them into position. We propose a method of directed assembly using dielectric contrast between the components and a surrounding fluid. A hybrid integrated-circuit / microfluidic device will be used to trap and manipulate pieces into pre-defined patterns. The device contains an array of electrically-chargeable pixels on its surface, with a resolution of 10 μ m. Thomas Hunt, David Issadore, Robert Westervelt ``Integrated Circuit/Microfluidic Chip to Programmably Trap and Move Cells and Droplets with Dielectrophoresis'' Lab on a Chip 8, 81-87 (2008)

  1. Diffraction-limited 10 microns imaging with 3 meter telescopes

    NASA Technical Reports Server (NTRS)

    Bloemhof, E. E.; Townes, C. H.; Vanderwyck, A. H. B.

    1986-01-01

    An IR imaging system that achieves diffraction-limited spatial resolution (about 0.8 arcsec) at 10 microns on 3-meter ground-based telescopes. The system uses a linear array of sensitive HgCdTe photodiodes, scanned in the direction perpendicular to the array axis, to form two-dimensional images. Scans are completed rapidly enough to freeze atmospheric fluctuations. Individual detectors are small compared to the diameter of the Airy disk, and images are oversampled heavily in the scan direction. This method has a number of advantages for studying small fields with very high spatial resolution, and has been applied successfully to the problem of directly imaging faint circumstellar dust shells.

  2. The 4 micron spectra of compact infrared sources

    NASA Technical Reports Server (NTRS)

    Hofmann, R.; Larson, H. P.; Fink, U.

    1986-01-01

    High resolution 5 arcsec spectra in the 4 micron region are presented of the central 5 arcsec of the compact near infrared sources K3-50, W51-IRS2 East, and G333.6-0.2. From measured Br-alpha/Pf-beta line ratios and previously published infrared and radio maps, it is concluded that standard recombination theory fails to explain our observations in at least two cases. It is demonstrated that the data are consistent with thermal excitation of the hydrogen lines in strong stellar winds. The Pf-beta Hu-epsilon line ratio, which is completely insensitive to differential extinction, confirms the need for the stellar wind model for the core of G333.6-0.2. From the (K III) line it is estimated that the potassium abundance in G333.6-0.2 is at least equal to the solar value, and possibly enhanced by a factor up to 10.

  3. Densities of 5-15 micron interplanetary dust particles

    NASA Technical Reports Server (NTRS)

    Love, S. G.; Joswiak, D. J.; Brownlee, D. E.

    1993-01-01

    We have measured the densities of about 100 5-15 micron stratospheric IDPs. Great care was taken to minimize selection bias in the sample population. Masses were determined using an absolute x-ray analysis technique with a transmission electron microscope, and volumes were found using scanning electron microscope imagery. Unmelted chondritic particles have densities between 0.5 and 6.0 g/cc. Roughly half of the particles have densities below 2 g/cc, indicating appreciable porosity, but porosities greater than about 70 percent are rare. IDPs with densities above 3.5 g/cc usually contain large sulfide grains. We find no evidence of bimodality in the unmelted particle density distribution. Chondritic spherules (melted particles) have densities near 3.5 g/cc, consistent with previous results for deep sea spherules.

  4. Multiple-Instrument Analyses of Single Micron-Size Particles

    NASA Astrophysics Data System (ADS)

    Admon, Uri; Donohue, David; Aigner, Helmut; Tamborini, Gabriele; Bildstein, Olivier; Betti, Maria

    2005-08-01

    Physical, chemical, and isotopic analyses of individual radioactive and other particles in the micron-size range, key tools in environmental research and in nuclear forensics, require the ability to precisely relocate particles of interest (POIs) in the secondary ion mass spectrometer (SIMS) or in another instrument, after having been located, identified, and characterized in the scanning electron microscope (SEM). This article describes the implementation, testing, and evaluation of the triangulation POIs re-location method, based on microscopic reference marks imprinted on or attached to the sample holder, serving as an inherent coordinate system. In SEM-to-SEM and SEM-to-SIMS experiments re-location precision better than 10 [mu]m and 20 [mu]m, respectively, is readily attainable for instruments using standard specimen stages. The method is fast, easy to apply, and facilitates repeated analyses of individual particles in different instruments and laboratories.

  5. Passive athermalization of doublets in 8-13 micron waveband

    NASA Astrophysics Data System (ADS)

    Schuster, Norbert

    2014-10-01

    Passive athermalization of lenses has become a key-technology for automotive and other outdoor applications using modern uncooled 25, 17 and 12 micron pixel pitch bolometer arrays. Typical pixel counts for thermal imaging are 384x288 (qVGA), 640x480 (VGA), and 1024x768 (XGA). Two lens arrangements (called Doublets) represent a cost effective way to satisfy resolution requirements of these detectors with F-numbers 1.4 or faster. Thermal drift of index of refraction and the geometrical changes (in lenses and housing) versus temperature defocus the initial image plane from the detector plane. The passive athermalization restricts this drop of spatial resolution in a wide temperature range (typically -40°C…+80°C) to an acceptable value without any additional external refocus. In particular, lenses with long focal lengths and high apertures claim athermalization. A careful choice of lens and housing materials and a sophistical dimensioning lead to three different principles of passivation: The Passive Mechanical Athermalization (PMA) shifts the complete lens cell, the Passive Optical and Mechanical Athermalization (POMA) shifts only one lens inside the housing, the Passive Optical Athermalization (POA) works without any mechanism. All three principles will be demonstrated for a typical narrow-field lens (HFOV about 12°) with high aperture (aperture based F-number 1.3) for the actual uncooled reference detector (17micron VGA). Six design examples using different combinations of lens materials show the impact on spatial lens resolution, on overall length, and on weight. First order relations are discussed. They give some hints for optimization solutions. Pros and cons of different passive athermalization principles are evaluated in regards of housing design, availability of materials and costing. Examples with a convergent GASIR®1-lens in front distinguish by best resolution, short overall length, and lowest weight.

  6. The 11 micron Silicon Carbide Feature in Carbon Star Shells

    NASA Technical Reports Server (NTRS)

    Speck, A. K.; Barlow, M. J.; Skinner, C. J.

    1996-01-01

    Silicon carbide (SiC) is known to form in circumstellar shells around carbon stars. SiC can come in two basic types - hexagonal alpha-SiC or cubic beta-SiC. Laboratory studies have shown that both types of SiC exhibit an emission feature in the 11-11.5 micron region, the size and shape of the feature varying with type, size and shape of the SiC grains. Such a feature can be seen in the spectra of carbon stars. Silicon carbide grains have also been found in meteorites. The aim of the current work is to identity the type(s) of SiC found in circumstellar shells and how they might relate to meteoritic SiC samples. We have used the CGS3 spectrometer at the 3.8 m UKIRT to obtain 7.5-13.5 micron spectra of 31 definite or proposed carbon stars. After flux-calibration, each spectrum was fitted using a chi(exp 2)-minimisation routine equipped with the published laboratory optical constants of six different samples of small SiC particles, together with the ability to fit the underlying continuum using a range of grain emissivity laws. It was found that the majority of observed SiC emission features could only be fitted by alpha-SiC grains. The lack of beta-SiC is surprising, as this is the form most commonly found in meteorites. Included in the sample were four sources, all of which have been proposed to be carbon stars, that appear to show the SiC feature in absorption.

  7. Mass Spectrometry of Atmospheric Aerosol: 1 nanometer to 1 micron

    NASA Astrophysics Data System (ADS)

    Worsnop, D. R.; Ehn, M.; Junninen, H.; Kulmala, M. T.

    2010-12-01

    The role of aerosol particles remains the largest uncertainty in quantitatively assessing past, current and future climate change. The principal reason for that uncertainty arises from the need to characterize and model composition and size dependent aerosol processes, ranging from nanometer to micron scales. Aerosol mass spectrometry results have shown that about half the sub-micron aerosol composition is composed of highly oxygenated organics that are not well understood in terms of photochemical reaction mechanisms (Jimenez et al, 2009). This work has included application of high resolution time-of-flight mass spectrometry (ToFMS) in order to determine elemental and functional group composition of complex organic components. Recently, we have applied similar ToFMS to determine the composition of ambient ions, molecules and clusters, potentially involved in formation and growth of nano-particles (Junninen et al, 2010). Observed organic anions (molecular weight range 200-500 Th) have similar chemical composition as the least volatile secondary organics observed in fine particles; while organic cations are dominated by amines and pyridines. During nucleation events, anions are dominated by sulphuric acid cluster ions (Ehn et al, 2010). In both nanometer and micrometer size ranges, the goal to elucidate the roles of inorganic and organic species, particularly how particle evolution and physical properties depend on mixed compositions. Recent results will be discussed, including ambient and experimental chamber observations. Ehn et al, Atmos. Chem. Phys. Discuss., 10, 14897-14946, 2010 Jimenez et al, Science, 326, 1525-1529, 2009 Junninen et al, Atmos. Meas. Tech., 3, 1039-1053, 2010

  8. The interaction of bromine with micron and submicron aerosols.

    PubMed

    Spatola, J A; Gentry, J W

    1980-11-01

    This study was undertaken to gain a better understanding of the reactions of aerosols with gases and vapors. The experimental system was designed in which both phases were dispersed. A collision-type nebulizer was used to generate monodisperse aerosols of 0.234, 0.500, 0.804, 1.101 and 2.020 microns diameter. Bromine concentrations of 100 and 200 ppm were produced to interact with the aerosolS. A light-scattering optical particle counter was used to determine the particle number concentration. Reacted aerosol collected on Teflon filters was analyzed by energy-dispersive x-ray fluorescence. Two temperature regimes were selected: approximately 26 degrees C and 60 degrees C. Separate runs were also conducted for the extreme case of zero curvature using 25 microns thick polystyrene sheet. Data generated from this study show a strong dependence of bromine levels on particle size. As the particle size increased, the amount of bromine per particle (ng Br/particle) also increased. However, on a weight-to-weight basis (ng Br/ng aerosol), the amount of bromine was found to increase with decreasing particle size. The concentration dependence on particle diameter was more strongly associated with values between d2 and d3. This dependence, together with other experimental data, supports a shrinking-unreacted core physical model for the actual reaction. When Br2 concentration or reaction temperature was increased, higher levels of bromine resulted in the aerosol. Runs where both temperature and concentration were increased showed lower levels of bromine than with an increase in either variable. One possible explanation is that the relative rates of reaction on the surface of the particle and diffusion through the reacted shell may be the influencing factors. Brominated polystyrene sheet material showed substantially lower bromine levels than the aerosols. PMID:7457368

  9. Fibre laser component technology for 2-micron laser systems

    NASA Astrophysics Data System (ADS)

    Stevens, G.; Robertson, A.

    2014-05-01

    We report on recent developments in fibre laser component technology for use in 2-micron laser systems. A range of `building block' components has been built to allow novel fibre laser architectures that exploit the advantages of fibre lasers based on Thulium and Holmium active fibres. Fibre lasers operating around 2-microns are becoming widely used in an increasing number of applications, which is driving the need for components that can operate reliably at high powers and also integrate easily with other components. To that end, we have designed and built a range of fused fibre, acousto-optic and magneto-optic devices that can be readily integrated into a range of novel fibre laser systems. Research has been carried out into improving fused fibre technology for components operating at 2um wavelengths. Side-coupled feed through combiners have been developed with signal losses as low as 0.02dB and kilowatt level end-coupled pump couplers. Alongside this a range of taps, splitters and WDMs have been developed which allows for the implementation of a variety of laser architectures. Optical isolators based on new Faraday materials have been developed, providing over 30dB isolation, low insertion loss and 30W power handling in a fibre-in, fibre-out version. New cell designs and materials for Acousto-Optic devices have been researched leading to the development of fibre-coupled Acousto-Optic Modulators (AOM) and allows for the realisation of all fibre Thulium and Holmium Q-switched and pulsed fibre lasers. Novel Acousto-Optic Tunable Filters (AOTF) designs have been realised to produce narrow resolution AOTFs and zero-shift AOTFs.

  10. Sources of the 13 Microns Feature Associated with Oxygen-Rich Circumstellar Dust

    NASA Technical Reports Server (NTRS)

    Sloan, G. C.; LeVan, P. D.; Little-Marenin, I. R.; Witteborn, Fred C. (Technical Monitor)

    1995-01-01

    A search of the database of spectra from the IRAS Low-Resolution Spectrometer has revealed 13 micron emission features in 187 sources, most of which are associated with stars embedded within oxygen-rich circumstellar dust shells. Our sample is very incomplete, but we estimate that 40-50% of all sources with oxygen-rich dust on the asymptotic giant branch (AGB) exhibit emission features at 13 microns. The similarities of the galactic distribution, mean radial velocities, infrared colors, and other properties of the sample of 13 micron sources compared to the parent population of variables on the AGB suggest that the carrier of the 13 micron feature is commonly produced in oxygen-rich dust environments. A strikingly large fraction of SRb variables show 13 micron features, approximately 75-90%, suggesting that the formation and/or survival of the carrier of the 13 micron feature may be enhanced by the unusual pulsational properties of these variables.

  11. The impact of micronized progesterone on the endometrium: a systematic review.

    PubMed

    Stute, P; Neulen, J; Wildt, L

    2016-08-01

    Postmenopausal women with an intact uterus using estrogen therapy should receive a progestogen for endometrial protection. International guidelines on menopausal hormone therapy (MHT) do not specify on progestogen type, dosage, route of application and duration of safe use. At the same time, the debate on bioidentical hormones including micronized progesterone increases. Based on a systematic literature review on micronized progesterone for endometrial protection, an international expert panel's recommendations on MHT containing micronized progesterone are as follows: (1) oral micronized progesterone provides endometrial protection if applied sequentially for 12-14 days/month at 200 mg/day for up to 5 years; (2) vaginal micronized progesterone may provide endometrial protection if applied sequentially for at least 10 days/month at 4% (45 mg/day) or every other day at 100 mg/day for up to 3-5 years (off-label use); (3) transdermal micronized progesterone does not provide endometrial protection. PMID:27277331

  12. Bidirectional reflectance measurement of zinc oxide in 0.25 to 2.5 microns spectrum

    NASA Technical Reports Server (NTRS)

    Scott, R. L., Jr.

    1974-01-01

    An experimental apparatus was designed and used to measure the bidirectional reflectance of zinc oxide in the spectrum 0.25 to 2.5 microns. The nonspecular reflectance is essentially Lambert for wavelengths above 0.40 microns with the most deviation occuring for large source zenith angles. Below 0.400 microns the nonspecular reflectance is greater than Lambert in all directions and is greatest in the forward and backscatter directions. The ratio of the specular component to the nonspecular component at a zenith of 0 degrees was found to increase with source zenith and wavelength for wavelengths above 0.400 microns. Below 0.400 microns this ratio increases as wavelengths decrease. The variation of bidirectional reflectance with wavelength was found to have the characteristics absorption for Zn0 for wavelength below 0.400 microns.

  13. Maintenance of the 2 microns circle plasmid in populations of Saccharomyces cerevisiae.

    PubMed Central

    Futcher, A B; Cox, B S

    1983-01-01

    The 2 microns circle plasmid is maintained at high frequencies in populations of yeast cells. To find out how the plasmid is maintained, three forces were measured: the selective advantage or disadvantage conferred by 2 microns circles, the rate of generation of [Cir0] cells, and the rate of illegitimate transfer of 2 microns circles from cell to cell. It was found that under the conditions used, 2 microns circles confer a selective disadvantage of about 1%, that [Cir0] cells are generated at the rate of 7.6 x 10(-5) per [Cir+] cell per generation, and that illegitimate transfer of 2 microns circles occurs at a rate less than 10(-7) per recipient cell per generation. The most likely explanation of 2 microns circle maintenance is that the plasmid is sexually transmitted at such a rate that it spreads through populations despite selection against it. Images PMID:6341357

  14. Venus - The 17- to 38-micron spectrum. [atmospheric thermal emission spectrum

    NASA Technical Reports Server (NTRS)

    Reed, R. A.; Forrest, W. J.; Houck, J. R.; Pollack, J. B.

    1978-01-01

    A far-IR emission spectrum of Venus covering the wavelength range from 17 to 38 microns is examined which was obtained on five nights at an altitude of 14 km with the 30-cm telescope of the NASA Lear Jet. The spectrum is found to be characterized by an overall continuum level with noticeable absorption shortward of 20 microns and longward of 30 microns as compared with a 245-K blackbody. The continuum level is taken as implying a continuous source of opacity in the Venusian atmosphere over the entire range from 17 to 38 microns with increased opacity shortward of 20 microns and longward of 30 microns. It is shown that a haze of sulfuric acid droplets can provide the necessary opacity and explain the observed depressions. A pressure level of roughly 200 mb is deduced for this spectrum.

  15. High-resolution spectra of the 3.29 micron interstellar emission feature - A summary

    NASA Technical Reports Server (NTRS)

    Tokunaga, A. T.; Sellgren, K.; Smith, R. G.; Nagata, T.; Sakata, A.; Nakada, Y.

    1991-01-01

    High spectral resolution observations of the 3.29-micron interstellar emission feature show two types of profiles. Type 1 has a central wavelength of 3.289-micron and is observed in extended objects such as planetary nebulae and H II regions. Type 2 has a central wavelength of 3.296 microns and is observed around a small number of stellar sources. Type 2 has a full width at half-maximum of 0.020 micron; Type 1 has a broader FWHM, perhaps as much as 0.042 micron, but this is uncertain because of contamination by Pf(delta) emission. These profiles are tabulated for comparison to laboratory data. It is found that no proposed identification for the 3.29-micron emission feature definitely matches the observational spectra, although amorphous aromatic materials and heated polycyclic aromatic hydrocarbons tend to fit the best.

  16. Mass loss rates from protostars and OI(63 micron) shock luminosities

    NASA Technical Reports Server (NTRS)

    Hollenbach, D.

    1985-01-01

    The high-velocity ejection of material from protostars results in a wind shock which may be observable in OI(63 micron) emission. It is shown that for a wide range of conditions, the OI(63 micron) luminosity is proportional to the mass loss rate from the protostar. Application is made to shock OI(63 micron) emission observed around IRc2 in the BN-KL region of Orion.

  17. Toward Developing a Preventive MERS-CoV Vaccine-Report from a Workshop Organized by the Saudi Arabia Ministry of Health and the International Vaccine Institute, Riyadh, Saudi Arabia, November 14-15, 2015.

    PubMed

    Excler, Jean-Louis; Delvecchio, Christopher J; Wiley, Ryan E; Williams, Marni; Yoon, In-Kyu; Modjarrad, Kayvon; Boujelal, Mohamed; Moorthy, Vasee S; Hersi, Ahmad Salah; Kim, Jerome H

    2016-08-01

    Middle East respiratory syndrome (MERS) remains a serious international public health threat. With the goal of accelerating the development of countermeasures against MERS coronavirus (MERS-CoV), funding agencies, nongovernmental organizations, and researchers across the world assembled in Riyadh, Saudi Arabia, on November 14-15, 2015, to discuss vaccine development challenges. The meeting was spearheaded by the Saudi Ministry of Health and co-organized by the International Vaccine Institute, South Korea. Accelerating the development of a preventive vaccine requires a better understanding of MERS epidemiology, transmission, and pathogenesis in humans and animals. A combination of rodent and nonhuman primate models should be considered in evaluating and developing preventive and therapeutic vaccine candidates. Dromedary camels should be considered for the development of veterinary vaccines. Several vaccine technology platforms targeting the MERS-CoV spike protein were discussed. Mechanisms to maximize investment, provide robust data, and affect public health are urgently needed. PMID:27439020

  18. Mapping and spectroscopy of the 3.3 microns feature in Orion

    NASA Technical Reports Server (NTRS)

    Sellgren, K.; Tokunaga, A. T.; Nakada, Y.

    1989-01-01

    The results of spectroscopy of the 3.3 microns feature, H2 emission, and Br alpha, obtained in a spatial cut across the Orion ionization front are presented. The spatial distribution of the 3.3 microns feature peaks between the ionization front and the H2 peak are observed. The shape of the 3.3 microns feature observed at high spectral resolution shows no changes in regions of varying ultraviolet flux and density. The results are discussed in terms of current models for the 3.3 microns emission feature.

  19. Spatial variations of the 3-micron emission features within Orion's Bar

    NASA Technical Reports Server (NTRS)

    Moorhouse, A.; Brand, P. W. J. L.; Geballe, T. R.; Allamandola, L. J.; Tielens, A. G. G. M.

    1988-01-01

    3-micron spectra of the Orion Bar region have been obtained at three positions corresponding to different distances from the exciting source. The recently discovered unidentified features at 3.46, 3.51, and 3.57 microns are clearly visible. The spectra show that the 3.4 and 3.51-micron emission features increase in intensity relative to the strong 3.3-micron feature as the distance from the exciting source increases. The implications for polycyclic aromatic hydrocarbons and recent ideas concerning their ultraviolet excitation and spatial evolution are discussed.

  20. Evaluation of micron size carbon fibers released from burning graphite composites

    NASA Technical Reports Server (NTRS)

    Sussholz, B.

    1980-01-01

    Quantitative estimates were developed of micron carbon fibers released during the burning of graphite composites. Evidence was found of fibrillated particles which were the predominant source of the micron fiber data obtained from large pool fire tests. The fibrillation phenomena were attributed to fiber oxidation effects caused by the fire environment. Analysis of propane burn test records indicated that wind sources can cause considerable carbon fiber oxidation. Criteria estimates were determined for the number of micron carbon fibers released during an aircraft accident. An extreme case analysis indicated that the upper limit of the micron carbon fiber concentration level was only about half the permissible asbestos ceiling concentration level.

  1. Selection of quasi-monodisperse super-micron aerosol particles

    NASA Astrophysics Data System (ADS)

    Rösch, Michael; Pfeifer, Sascha; Wiedensohler, Alfred; Stratmann, Frank

    2014-05-01

    Size-segregated quasi monodisperse particles are essential for e.g. fundamental research concerning cloud microphysical processes. Commonly a DMA (Differential Mobility Analyzer) is used to produce quasi-monodisperse submicron particles. Thereto first, polydisperse aerosol particles are bipolarly charged by a neutralizer, and then selected according to their electrical mobility with the DMA [Knutson et al. 1975]. Selecting a certain electrical mobility with a DMA results in a particle size distribution, which contains singly charged particles as well as undesired multiply charged larger particles. Often these larger particles need to either be removed from the generated aerosol or their signals have to be corrected for in the data inversion and interpretation process. This problem becomes even more serious when considering super-micron particles. Here we will present two different techniques for generating quasi-monodisperse super-micron aerosol particles with no or only an insignificant number of larger sized particles being present. First, we use a combination of a cyclone with adjustable aerodynamic cut-off diameter and our custom-built Maxi-DMA [Raddatz et al. 2013]. The cyclone removes particles larger than the desired ones prior to mobility selection with the DMA. This results in a reduction of the number of multiply charged particles of up to 99.8%. Second, we utilize a new combination of cyclone and PCVI (Pumped Counterflow Virtual Impactor), which is based on purely inertial separation and avoids particle charging. The PCVI instrument was previously described by Boulter et al. (2006) and Kulkarni et al. (2011). With our two setups we are able to produce quasi-monodisperse aerosol particles in the diameter range from 0.5 to 4.4 µm without a significant number of larger undesired particles being present. Acknowledgements: This work was done within the framework of the DFG funded Ice Nucleation research UnIT (INUIT, FOR 1525) under WE 4722/1-1. References

  2. Viewing Seasonality in 8 Megacities at 4 Microns

    NASA Astrophysics Data System (ADS)

    Tomaszewska, M. A.; Kovalskyy, V.; Small, C.; Henebry, G. M.

    2013-12-01

    The middle infrared (MIR) spectral region, between 3 and 5 microns, offers a different perspective on cities. The MIR is the mixing zone of both emitted terrestrial radiation and reflected solar radiation. The relatively long wavelengths enable views of surfaces often obscured by anthropogenic haze. Green vegetation appears very dark in the MIR due to high absorption by leaf water. In contrast, building, roofing, and paving materials reflect much MIR and exposed soils and dried vegetation reflect even more. Thus, physics dictates a strong expression of seasonality in the MIR. But is there sufficient signal in the MIR to merit it as a complementary approach for characterizing urbanized areas and monitoring their dynamics? We have explored this question in a research effort that links two NASA Interdisciplinary Science projects on the effect of cities on the environment. We focused on 8 global megacities: Beijing, Cairo, Istanbul, Mexico, Moscow, Nairobi, New Delhi, and São Paulo. We used Level 1B calibrated radiance data from band 23 (~4 microns) of the Aqua MODIS during ascending passes in 2010. These 1 km data were processed to reduce cloud cover using monthly maximum value compositing into four sensor view zenith angle (VZA) classes: 030°). SNR was higher in the summer

  3. Discovering Motifs in Biological Sequences Using the Micron Automata Processor.

    PubMed

    Roy, Indranil; Aluru, Srinivas

    2016-01-01

    Finding approximately conserved sequences, called motifs, across multiple DNA or protein sequences is an important problem in computational biology. In this paper, we consider the (l, d) motif search problem of identifying one or more motifs of length l present in at least q of the n given sequences, with each occurrence differing from the motif in at most d substitutions. The problem is known to be NP-complete, and the largest solved instance reported to date is (26,11). We propose a novel algorithm for the (l,d) motif search problem using streaming execution over a large set of non-deterministic finite automata (NFA). This solution is designed to take advantage of the micron automata processor, a new technology close to deployment that can simultaneously execute multiple NFA in parallel. We demonstrate the capability for solving much larger instances of the (l, d) motif search problem using the resources available within a single automata processor board, by estimating run-times for problem instances (39,18) and (40,17). The paper serves as a useful guide to solving problems using this new accelerator technology. PMID:26886735

  4. Micron-scale coherence in interphase chromatin dynamics

    PubMed Central

    Zidovska, Alexandra; Weitz, David A.; Mitchison, Timothy J.

    2013-01-01

    Chromatin structure and dynamics control all aspects of DNA biology yet are poorly understood, especially at large length scales. We developed an approach, displacement correlation spectroscopy based on time-resolved image correlation analysis, to map chromatin dynamics simultaneously across the whole nucleus in cultured human cells. This method revealed that chromatin movement was coherent across large regions (4–5 µm) for several seconds. Regions of coherent motion extended beyond the boundaries of single-chromosome territories, suggesting elastic coupling of motion over length scales much larger than those of genes. These large-scale, coupled motions were ATP dependent and unidirectional for several seconds, perhaps accounting for ATP-dependent directed movement of single genes. Perturbation of major nuclear ATPases such as DNA polymerase, RNA polymerase II, and topoisomerase II eliminated micron-scale coherence, while causing rapid, local movement to increase; i.e., local motions accelerated but became uncoupled from their neighbors. We observe similar trends in chromatin dynamics upon inducing a direct DNA damage; thus we hypothesize that this may be due to DNA damage responses that physically relax chromatin and block long-distance communication of forces. PMID:24019504

  5. Tests of Gravity Below the 50-micron Distance Scale

    NASA Astrophysics Data System (ADS)

    Smith, David; Hoyle, C. D.; Leopardi, Holly

    2012-11-01

    Though it is the oldest recognized of the fundamental forces, tests of gravity remain at the forefront of experimental physics research. Due to the incompatibility of the Standard Model and General Relativity, there is no accepted Unified Field Theory, though some attempts to construct such a model via String Theory predict more than three spatial dimensions that could alter the gravitational Inverse-Square Law at short distances. Certain scenarios also predict unobserved subatomic particles that may cause short-range violations of the Weak Equivalence Principle. The Gravitational Research Laboratory at Humboldt State University, a collaboration of undergraduate students and faculty, is developing an experiment that will test gravitational interactions below the 50-micron distance scale. The experiment will measure the torque applied to a torsion pendulum as an attractor mass is oscillated nearby. The size and distance dependence of the torque variation will provide a means to determine any deviations from Newtonian gravity at heretofore untested scales. The major components of the experiment have been designed and fabricated including a novel stepped parallel-plate torsion pendulum and a high-precision optical angle detection system. This talk will provide a general overview of the experiment and focus primarily on current status and expected outcomes.

  6. Images of the 10-micron source in the Cygnus 'Egg'

    NASA Technical Reports Server (NTRS)

    Jaye, D.; Fienberg, R. Tresch; Fazio, G. G.; Gezari, D. Y.; Lamb, G. M.; Shu, P. K.; Hoffmann, W. F.; Mccreight, C. R.

    1989-01-01

    Mid-IR images of AFGL 2688, the Egg nebula, obtained with a 16 x 16 pixel array camera (field of view 12.5 x 12.5 arcsec) resolve the central source. It appears as a centrally peaked ellipsoid with major axis of symmetry parallel to the axis of the visible nebulosity. This is contrary to the expected extension perpendicular to this axis implied by proposed dust-toroid models of the IR source. Maps of the spatial distribution of 8-13 micron color temperature and warm dust opacity derived from the multiwavelength images further characterize the IR emission. The remarkable flatness of the color temperature conflicts with the radial temperature gradient expected across a thick shell of material with a single heat source at its center. The new data suggest instead that the source consists of a central star surrounded by a dust shell that is too thin to provide a detectable temperature gradient and too small to permit the resolution of limb brightening.

  7. Micronized Coal Reburning Demonstration for NOx Control: A DOE Assessment

    SciTech Connect

    National Energy Technology Laboratory

    2001-08-15

    The goal of the U.S. Department of Energy's (DOE) Clean Coal Technology (CCT) program is to furnish the energy marketplace with a number of advanced, more efficient, and environmentally responsible coal utilization technologies through demonstration projects. These projects seek to establish the commercial feasibility of the most promising advanced coal technologies that have developed beyond the proof-of-concept stage. This document serves as a DOE post-project assessment of a project selected in CCT Round IV, the Micronized Coal Reburning (MCR) Demonstration for NO{sub x} Control, as described in a report to Congress (U.S. Department of Energy 1999). The need to meet strict emissions requirements at a minimum cost prompted the Tennessee Valley Authority (TVA), in conjunction with Fuller Company, Energy and Environmental Research Corporation (EER), and Fluor Daniel, to submit the proposal for this project to be sited at TVA's Shawnee Fossil Plant. In July 1992, TVA entered into a cooperative agreement with DOE to conduct the study. However, because of operational and environmental compliance strategy changes, the Shawnee site became unavailable.

  8. Mechanical characterization of sub-micron polytetrafluoroethylene (PTFE) thin films

    SciTech Connect

    Lucas, B.N.; Oliver, W.C.; Rosenmayer, C.T.

    1998-12-31

    This study reports the results of an investigation of the mechanical properties of polytetrafluoroethylene (PTFE) thin films on silicon substrates in the 0.5 to 15 {micro}m thickness regime using frequency specific depth-sensing indentation. All measurements were conducted at an excitation frequency of 45 Hz using a constant (1/P dP/dt) load ramp of 0.1 s{sup {minus}1}. The modulus of the PTFE at a depth of 5% of the film thickness was measured to be approximately 1 GPa ({nu} = 0.46) independent of film thickness. These values are somewhat higher than the values obtained from free-standing 15 {micro}m film measurements of 0.4 GPa for the tensile modulus and 0.49 GPa for the storage modulus {at} 1.1 Hz. The film hardness at these depths was observed to range between 30 and 55 MPa with no correlation observed between the hardness and respective film thickness. While reliability modeling for interconnects currently uses interlayer dielectric mechanical properties data determined from free-standing films with thicknesses of several microns, these in-situ results should more closely mimic the constrained deformation that occurs during service and perhaps lead to a better understanding of the electromigration resistance of PTFE.

  9. Fourier-transform spectroscopy of O3 in the 3-micron region

    NASA Technical Reports Server (NTRS)

    Smith, M. A. H.; Rinsland, C. P.; Malathy Devi, V.; Flaud, J.-M.; Camy-Peyret, C.

    1989-01-01

    Fourier transform spectra of ozone have been recorded in the 2-5-micron region at a resolution of 0.01/cm. Absorption lines belonging to numerous vibration-rotation transitions have been observed in these spectra, and a detailed analysis of the band system centered at 3.6 microns has been completed.

  10. Separating the signal from the noise: Expanding flow cytometry into the sub-micron range.

    EPA Science Inventory

    Cytometry Part A Special Section: Separating the signal from the noise: Expanding flow cytometry into the sub-micron range. The current Cytometry Part A Special Section presents three studies that utilize cytometers to study sub-micron particles. The three studies involve the 1...

  11. Method of producing carbon coated nano- and micron-scale particles

    DOEpatents

    Perry, W. Lee; Weigle, John C; Phillips, Jonathan

    2013-12-17

    A method of making carbon-coated nano- or micron-scale particles comprising entraining particles in an aerosol gas, providing a carbon-containing gas, providing a plasma gas, mixing the aerosol gas, the carbon-containing gas, and the plasma gas proximate a torch, bombarding the mixed gases with microwaves, and collecting resulting carbon-coated nano- or micron-scale particles.

  12. Wavelength Shifts of the 7.7 Micron Emission Band in Reflection Nebulae

    NASA Technical Reports Server (NTRS)

    Bregman, Jesse; Temi, Pasquale

    2003-01-01

    Using spatial-spectral data cubes of reflection nebulae obtained by ISOCAM, we have observed a shift in the central wavelength of the 7.7 micron band within several reflection nebulae. The band shifts progressively from approx. 7.8 microns near the edge of the nebulae to approx. 7.6 microns towards the center of the nebulae. The ratio of the 11.3/7.7 micron bands also changes with distance from the central star, first rising from the center towards the edge of the nebula, then falling at the largest distances from the star, consistent with the 11.3/7.7 micron band ratio being controlled by the PAH ionization state. The behavior of the 7.7 micron band center can be explained either by assuming that anions are the origin of the 7.85 micron band and cations the 7.65 micron band, or that the band center wavelength depends on the chemical nature of the PAHs.

  13. An overview on in situ micronization technique – An emerging novel concept in advanced drug delivery

    PubMed Central

    Vandana, K.R.; Prasanna Raju, Y.; Harini Chowdary, V.; Sushma, M.; Vijay Kumar, N.

    2013-01-01

    The use of drug powders containing micronized drug particles has been increasing in several pharmaceutical dosage forms to overcome the dissolution and bioavailability problems. Most of the newly developed drugs are poorly water soluble which limits dissolution rate and bioavailability. The dissolution rate can be enhanced by micronization of the drug particles. The properties of the micronized drug substance such as particle size, size distribution, shape, surface properties, and agglomeration behaviour and powder flow are affected by the type of micronization technique used. Mechanical communition, spray drying and supercritical fluid (SCF) technology are the most commonly employed techniques for production of micronized drug particles but the characteristics of the resulting drug product cannot be controlled using these techniques. Hence, a newer technique called in situ micronization is developed in order to overcome the limitations associated with the other techniques. This review summarizes the existing knowledge on in situ micronization techniques. The properties of the resulting drug substance obtained by in situ micronization were also compared. PMID:25161371

  14. Pattern imprinting in deep sub-micron static random access memories induced by total dose irradiation

    NASA Astrophysics Data System (ADS)

    Zheng, Qi-Wen; Yu, Xue-Feng; Cui, Jiang-Wei; Guo, Qi; Ren, Di-Yuan; Cong, Zhong-Chao; Zhou, Hang

    2014-10-01

    Pattern imprinting in deep sub-micron static random access memories (SRAMs) during total dose irradiation is investigated in detail. As the dose accumulates, the data pattern of memory cells loading during irradiation is gradually imprinted on their background data pattern. We build a relationship between the memory cell's static noise margin (SNM) and the background data, and study the influence of irradiation on the probability density function of ΔSNM, which is the difference between two data sides' SNMs, to discuss the reason for pattern imprinting. Finally, we demonstrate that, for micron and deep sub-micron devices, the mechanism of pattern imprinting is the bias-dependent threshold shift of the transistor, but for a deep sub-micron device the shift results from charge trapping in the shallow trench isolation (STI) oxide rather than from the gate oxide of the micron-device.

  15. 20-micron transparency and atmospheric water vapor at the Wyoming Infrared Observatory

    NASA Technical Reports Server (NTRS)

    Grasdalen, G. L.; Gehrz, R. D.; Hackwell, J. A.; Freedman, R.

    1985-01-01

    The atmospheric transparency at 19.5 and 23 microns from the Wyoming Infrared Observatory over the past six years has been examined. It is found that the transparency is largely controlled by the season. Four months: June, July, August, and September have very poor 20-micron transparency. During the rest of the year the transparency is usually quite good at 19.5 microns and moderately good at 23 microns. Using rawinsonde data and theoretical calculations for the expected infrared transparency, the measures of 20-micron transparency were calibrated in terms of atmospheric water-vapor content. The water vapor over the Wyoming Infrared Observatory is found to compare favorably with that above other proposed or developed sites: Mauna Kea, Mount Graham, and Wheeler Peak.

  16. The 3.5 micron light curves of long period variable stars. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Strecker, D. W.

    1973-01-01

    Infrared observations at an effective wavelength of 3.5 microns of a selected group of long period variable (LPV) stars are presented. Mira type and semiregular stars of M, S, and C spectral classifications were monitored throughout the full cycle of variability. Although the variable infrared radiation does not exactly repeat in intensity or time, the regularity is sufficient to produce mean 3.5 micron light curves. The 3.5 micron maximum radiation lags the visual maximum by about one-seventh of a cycle, while the minimum 3.5 micron intensity occurs nearly one-half cycle after infrared maximum. In some stars, there are inflections or humps on the ascending portion of the 3.5 micron light curve which may also be seen in the visual variations.

  17. Contribution to the benchmark for ternary mixtures: Measurement of the Soret and thermodiffusion coefficients of tetralin+isobutylbenzene+n-dodecane at a composition of (0.8/0.1/0.1) mass fractions by two-color optical beam deflection.

    PubMed

    Gebhardt, M; Köhler, W

    2015-04-01

    Within the framework of an international benchmark test we have performed measurements of the Soret and thermodiffusion coefficients of the organic ternary mixture (0.8/0.1/0.1 mass fraction) of 1,2,3,4-tetrahydronaphthaline (THN), isobutylbenzene (IBB) and n -dodecane (n C12) at 298.15K by means of a two-color optical beam deflection technique (OBD). The data evaluation procedure is based on a least squares fitting routine for an approximate analytical solution for the Soret cell problem. The condition number of the contrast factor matrix and standard error propagation are used for an error estimation for the measured Soret and thermodiffusion coefficients. The Soret coefficients obtained are S (') T(THN) = (1.20±0.09)×10(-3) K^-1, S (') T(IBB) = (- 0.34±0.14)×10(-3) K^-1, and S (') T(nC12) = (- 0.86±0.06)×10(-3) K^-1 and the corresponding thermodiffusion coefficients are D (') T(THN) = (0.72±0.26)×10(-12) m^2(s K)^-1, D (') T(IBB) = (- 0.22±0.42)×10(-12) m^2(s K)^-1, and D (') T(nC12) = (- 0.50±0.16)×10(-12) m^2(s K)^-1. These results will be used as ground-based reference data for the DCMIX project, where thermodiffusion experiments of ternary mixtures are measured in a microgravity environment aboard the International Space Station (ISS). PMID:25904305

  18. A micron resolution optical scanner for characterization of silicon detectors.

    PubMed

    Shukla, R A; Dugad, S R; Garde, C S; Gopal, A V; Gupta, S K; Prabhu, S S

    2014-02-01

    The emergence of high position resolution (∼10 μm) silicon detectors in recent times have highlighted the urgent need for the development of new automated optical scanners of micron level resolution suited for characterizing microscopic features of these detectors. More specifically, for the newly developed silicon photo-multipliers (SiPM) that are compact, possessing excellent photon detection efficiency with gain comparable to photo-multiplier tube. In a short time, since their invention the SiPMs are already being widely used in several high-energy physics and astrophysics experiments as the photon readout element. The SiPM is a high quantum efficiency, multi-pixel photon counting detector with fast timing and high gain. The presence of a wide variety of photo sensitive silicon detectors with high spatial resolution requires their performance evaluation to be carried out by photon beams of very compact spot size. We have designed a high resolution optical scanner that provides a monochromatic focused beam on a target plane. The transverse size of the beam was measured by the knife-edge method to be 1.7 μm at 1 - σ level. Since the beam size was an order of magnitude smaller than the typical feature size of silicon detectors, this optical scanner can be used for selective excitation of these detectors. The design and operational details of the optical scanner, high precision programmed movement of target plane (0.1 μm) integrated with general purpose data acquisition system developed for recording static and transient response photo sensitive silicon detector are reported in this paper. Entire functionality of scanner is validated by using it for selective excitation of individual pixels in a SiPM and identifying response of active and dead regions within SiPM. Results from these studies are presented in this paper. PMID:24593348

  19. The AGN Content of the Micron all Sky Survey

    NASA Technical Reports Server (NTRS)

    Cutri, R. M.

    2000-01-01

    The Two Micron All Sky Survey (2MASS) began routine operations from its northern facility on Mt. Hopkins, AZ in June of 1997, and from its southern facility on Cerro Tololo, Chile in March of 1998. At each site, highly automated 1.3 m telescopes equipped with identical 3-channel cameras, are systematically imaging the sky in three near infrared wavelength bands, J (1.25 um), H (1.65 um) and K-s (2.17 um). The Survey will ultimately produce an Image Atlas containing nearly two million 512 x 1024 pixel images (1 arcsec/pix) in the three colors, a highly complete and reliable catalog containing approx. 300 million point sources having SNR greater than 10 photometry at J less or = 15.8, H less or = 15.1 and K-s less or = 14.3 mag. and an astrometric accuracy greater than 0.511 RMS, and a catalog of 1-2 million resolved sources, primarily galaxies, having SNR greater than 10 photometric accuracy at J less than or = 15.5, H less than or = 14.8 and K-s less than or = 13.5 mag. The 2MASS Sampler, an introductory set of data, was released to the community in December of 1998 (see http://www.ipac.caltech.edu/2mass/). We review the near IR and optical/IR properties of "conventional" QSOs from UV and optical samples, and estimate the number that will be detected by 2MASS. We also discuss 2MASS's ability to test for for new populations of extremely red AGN that have been missed by UV and Visual surveys, as suggested by from IRAS and radio studies. Results of spectroscopic follow-up of 2MASS-selected new AGN candidates will also be presented.

  20. The Two Micron All Sky Survey: One Year of Operations

    NASA Astrophysics Data System (ADS)

    Cutri, R. M.

    1998-05-01

    The Two Micron All Sky Survey (2MASS) began routine operations from its northern facility on Mt. Hopkins, AZ one year ago, and from its southern facility on Cerro Tololo, Chile in March of this year. At each site, 50-inch telescopes equipped with identical 3-channel cameras, are systematically imaging the sky in three near infrared wavelength bands, J (1.25mu m), H (1.65mu m) and K_s (2.17mu m). To date, over 10,000 deg(2) of sky have been observed. Ongoing processing and calibration of the survey image data produces three data products: 1) an Image Atlas that will eventually contain approximately one million 512x1024 pixel images (1 arcsec/pix) in the three colors, covering the full sky, 2) a highly complete and reliable catalog that will contain ~ 300 million point sources having SNR>10 photometry at J<=15.8, H<=15.1 and K_s<=14.3 mag. and an astrometric accuracy <0.5arcsec RMS, and 3) a catalog of approximately one million resolved sources, primarily galaxies, having SNR>10 photometric accuracy at J<=15.5, H<=14.8 and K_s<=13.5 mag. Incremental releases of these data products to the community are scheduled to begin in the Spring of 1999. A brief report on the current status and outlook for 2MASS will be given, along with analyses that demonstrate that the survey is achieving, if not exceeding its stated performance goals. Results of several pilot studies that are supporting 2MASS survey validation are presented as a preview of the tremendous scientific opportunities that will be available with the 2MASS databases. Key among these are investigations of the lowest mass objects in the solar neighborhood, probes of the structure of the Milky Way, and of the local universe, and the search for populations of extremely red active galactic nuclei.

  1. A micron resolution optical scanner for characterization of silicon detectors

    SciTech Connect

    Shukla, R. A.; Dugad, S. R. Gopal, A. V.; Gupta, S. K.; Prabhu, S. S.; Garde, C. S.

    2014-02-15

    The emergence of high position resolution (∼10 μm) silicon detectors in recent times have highlighted the urgent need for the development of new automated optical scanners of micron level resolution suited for characterizing microscopic features of these detectors. More specifically, for the newly developed silicon photo-multipliers (SiPM) that are compact, possessing excellent photon detection efficiency with gain comparable to photo-multiplier tube. In a short time, since their invention the SiPMs are already being widely used in several high-energy physics and astrophysics experiments as the photon readout element. The SiPM is a high quantum efficiency, multi-pixel photon counting detector with fast timing and high gain. The presence of a wide variety of photo sensitive silicon detectors with high spatial resolution requires their performance evaluation to be carried out by photon beams of very compact spot size. We have designed a high resolution optical scanner that provides a monochromatic focused beam on a target plane. The transverse size of the beam was measured by the knife-edge method to be 1.7 μm at 1 − σ level. Since the beam size was an order of magnitude smaller than the typical feature size of silicon detectors, this optical scanner can be used for selective excitation of these detectors. The design and operational details of the optical scanner, high precision programmed movement of target plane (0.1 μm) integrated with general purpose data acquisition system developed for recording static and transient response photo sensitive silicon detector are reported in this paper. Entire functionality of scanner is validated by using it for selective excitation of individual pixels in a SiPM and identifying response of active and dead regions within SiPM. Results from these studies are presented in this paper.

  2. Sub-micron retarding field energy analyzer for plasma analysis

    NASA Astrophysics Data System (ADS)

    Blain, Matthew

    1997-10-01

    A retarding field energy analyzer with sub-micron apertures for measurement of ion energy distributions in processing plasmas has been built. The analyzer was fabricated using standard Si integrated circuit materials and processing techniques and consists of a shielding grid, an electron repeller grid, and a collector plate, all made of 400 nm thick polycrystalline silicon thin films. The grids are supported and insulated from each other by 1 μm and 2 μm of SiO_2. The apertures in the grids are nominally 0.8 μm in diameter and are self-aligned, thereby minimizing field leakage and optimizing energy resolution. Ion trajectory modeling using SIMION predicts analyzer dispersion to be less than 0.1 eV for 20 eV incident ions. The analyzer can be operated on the wafer on which it was fabricated or can be separated into 1.6 x 1.2 cm^2 die for use as a discrete probe. The basic functionality of the analyzer has been demonstrated in inductively coupled argon plasmas and measurements show energy spreads of 3-5 eV which are consistent with the expected presheath voltage drops and agree well with measurements made with differentially pumped, macroscopic ion energy analyzers. Changes in mean ion energy as a function of power and pressure agree with the expected scaling trends. Efforts to passivate the Si surfaces with Ni to allow for operation of the analyzer in reactive gas plasmas are also reported.

  3. Galaxy clustering in the Two Micron All Sky Redshift Survey

    NASA Astrophysics Data System (ADS)

    Westover, Michael

    To make cosmological measurements using the galaxy distribution we must first understand galaxy biasing the way in which the galaxy distribution differs from the underlying matter distribution. Here I present studies of galaxy biasing using the Two Micron All Sky Redshift Survey, a near-infrared selected survey not subject to many of the selection effects that limit other samples. The relationship between galaxy bias and luminosity is steeper for our near- infrared selected sample than it is for optical samples, with b/b [low *] 0.73 + 0.24 L/L [low *] . I found no dependence upon luminosity in the relative bias between early and late morphologically typed galaxies once the mean dependence of bias upon luminosity was removed. I tested the relative biasing between early- and late-type galaxies using joint counts in cells. I found that a power law biasing model with b PL = 0.86-0.91 was a better fit than linear models. I did not see a significant increase in the quality of the fit when stochasticity was added to the model, in contrast with results from color- and spectral type-selected samples. I tested the hierarchical scaling hypothesis and confirmed that the scale factors S 3 , S 4 , and S 5 are independent of scale, as expected for a matter distribution evolved from Gaussian initial perturbations. There was no increase in the scale factors at large cell sizes as seen in some earlier surveys. I also measured the generalized dimensions D q using a multifractal analysis and found smaller values than have been seen in optically-selected surveys and simulations, indicating that galaxies in the near-infrared selected sample may be more likely to reside in filamentary rather than sheet-like structures.

  4. Dynamics of fluxes of protons with energies 30-80 keV during geomagnetic storms on January 21-22, 2005, and December 14-15, 2006, according to data from low-orbit satellites

    NASA Astrophysics Data System (ADS)

    Vlasova, N. A.; Kalegaev, V. V.

    2014-11-01

    We present the results of a comparative analysis of the dynamics of three populations of fluxes of protons with energy 30-80 keV as measured by NOAA solar-synchronous satellites ( POES 15, 16, 17) at low latitudes ( L < 2) and at latitudes lower and higher than the boundary of isotropic precipitation during the geomagnetic storms on January 21-22, 2005 and December 14-15, 2006. Based on a complex analysis of experimental data on particle fluxes at low orbits and on measurements of solar wind parameters performed by the ACE spacecraft, we have studied the dynamical peculiarities of the fluxes of particles and of their longitudinal distributions depending on the conditions in the interplanetary medium. It is shown that an increase of trapped particle fluxes and the development of the main phase of the geomagnetic storm on January 21-22, 2005 are associated with the magnetosphere's response to a prolonged action of an extremely powerful coronal mass ejection at a northern orientation of the IMF. On December 14, 2006 an insufficient amplitude and duration of the pressure impulse did not result in development of a disturbance similar to January 21-22, 2005. The development of the main phase of this storm is related to a southward turn of the IMF, which has occurred only seven hours after the SSC.

  5. The potential for high performance HgCdTe arrays at 4 microns

    NASA Technical Reports Server (NTRS)

    Rieke, G. H.; Sarfaraz, M. A.; Rieke, Marcia J.; Young, Erick T.

    1989-01-01

    The potential of existing technology at Rockwell International in terms of the goals for astronomical detector arrays in the 3 to 5 micron interval is evaluated. Measurements have been obtained for a number of samples of HgCdTe diodes manufactured by Rockwell International. All the diodes reported on here had cutoff wavelengths at high temperatures of 4.6 to 4.7 microns. Although no confirming measurements were made, the cutoff wavelength is expected to move to 5 microns or beyond at the low temperatures of our tests. Diode sizes ranged from 20 to 150 microns. The test program yielded full diode curves and relative response at 3.4 microns for the sample diodes as a function of temperature. Dark currents are quoted below as the current passing through the diode with a back bias of 50 mV. The various diode types showed a wide range of behavior, both with regard to dark current and responsibility. The test results for one of the best diode types are illustrated. This detector has a size of 148 microns and a cutoff wavelength of 4.61 microns.

  6. The 16-39 micron spectroscopy of oxygen-rich stars

    NASA Technical Reports Server (NTRS)

    Forrest, W. J.; Mccarthy, W. J.; Houck, J. R.

    1979-01-01

    Airborne observations of the 16-39 microns spectra of ten oxygen-rich stars with excess emission in the infrared was obtained. The stars show excess emission attributed to circumstellar dust grains in the 16-39 microns region in the form of a broad hump peaking near 18 microns and falling smoothly to longer wavelengths. The emission is similar in character to the emission from the Trapezium region of the Orion nebula indicating the grain materials are quite similar in these objects. The existence of a feature in the 20 microns region is consistent with the 0-Si-0 bending resonance expected for silicate material. The lack of any sharp structure in the spectra indicates the silicate is in an amorphous, disordered form. A simple model of small grains of carbonaceous chondrite silicate material in a diffuse circumstellar envelope is shown to give a good qualitative fit to the observed 8-39 microns circumstellar spectra. Comparison of the observed spectra with the model spectra indicates the grain emissivity falls as 1/lambda squared from 20 microns to 40 microns.

  7. IS THE TWO MICRON ALL SKY SURVEY CLUSTERING DIPOLE CONVERGENT?

    SciTech Connect

    Bilicki, Maciej; Chodorowski, Michal; Jarrett, Thomas; Mamon, Gary A.

    2011-11-01

    There is a long-standing controversy about the convergence of the dipole moment of the galaxy angular distribution (the so-called clustering dipole). Is the dipole convergent at all, and if so, what is the scale of the convergence? We study the growth of the clustering dipole of galaxies as a function of the limiting flux of the sample from the Two Micron All Sky Survey (2MASS). Contrary to some earlier claims, we find that the dipole does not converge before the completeness limit of the 2MASS Extended Source Catalog, i.e., up to 13.5 mag in the near-infrared K{sub s} band (equivalent to an effective distance of 300 Mpc h{sup -1}). We compare the observed growth of the dipole with the theoretically expected, conditional one (i.e., given the velocity of the Local Group relative to the cosmic microwave background), for the {Lambda}CDM power spectrum and cosmological parameters constrained by the Wilkinson Microwave Anisotropy Probe. The observed growth turns out to be within 1{sigma} confidence level of its theoretical counterpart once the proper observational window of the 2MASS flux-limited catalog is included. For a contrast, if the adopted window is a top hat, then the predicted dipole grows significantly faster and converges (within the errors) to its final value for a distance of about 300 Mpc h{sup -1}. By comparing the observational windows, we show that for a given flux limit and a corresponding distance limit, the 2MASS flux-weighted window passes less large-scale signal than the top-hat one. We conclude that the growth of the 2MASS dipole for effective distances greater than 200 Mpc h{sup -1} is only apparent. On the other hand, for a distance of 80 Mpc h{sup -1} (mean depth of the 2MASS Redshift Survey) and the {Lambda}CDM power spectrum, the true dipole is expected to reach only {approx}80% of its final value. Eventually, since for the window function of 2MASS the predicted growth is consistent with the observed one, we can compare the two to evaluate

  8. Low-dosage micronized 17 beta-estradiol prevents bone loss in postmenopausal women

    NASA Technical Reports Server (NTRS)

    Ettinger, B.; Genant, H. K.; Steiger, P.; Madvig, P.

    1992-01-01

    With the use of a double-blind, randomized, dose-ranging design, we tested during an 18-month period the degree of protection against postmenopausal bone loss afforded by micronized 17 beta-estradiol in dosages of 0.5, 1.0, and 2.0 mg. All subjects received supplementation to ensure a minimum of 1500 mg calcium daily. Fifty-one subjects completed at least 1 year of follow-up bone density measurements by quantitative computed tomography and by single- and dual-photon absorptiometry. In the placebo group spinal trabecular bone density decreased 4.9% annually (p less than 0.001), whereas in those taking micronized 17 beta-estradiol bone density tended to increase (annual increases of 0.3% in the 0.5 mg micronized 17 beta-estradiol group, 1.8% in the 1.0 mg micronized 17 beta-estradiol group, and 2.5% in the 2.0 mg micronized 17 beta-estradiol group). After completing the double-blind phase, 41 subjects completed an additional 18 months of follow-up while taking 1.0 mg micronized 17 beta-estradiol. During this time one third of the subjects were randomly assigned to discontinue calcium supplements. Among those who previously received placebo, trabecular bone density increased 4.3% annually, whereas among those who had used micronized 17 beta-estradiol, trabecular bone density response was inversely related to the dosage previously used. Additionally and independently, the level of calcium intake showed a statistically significant correlation with the change in spinal trabecular bone density (r = 0.37, p = 0.02). We conclude that micronized 17 beta-estradiol has a continuous skeletal dose-response effect in the range of 0.5 to 2.0 mg and that calcium intake positively modifies the skeletal response to 1.0 mg micronized 17 beta-estradiol.

  9. Titan - 1.5 micron photometry and spectrophotometry and a search for variability

    NASA Astrophysics Data System (ADS)

    Noll, K. S.; Knacke, R. F.

    1993-02-01

    The first photometric measurements of Titan in the mid-IR free of possible contamination from long-wavelength filter leaks are reported. A low-resolution spectrum covering the last unobserved gap in Titan's near-IR spectrum from 3.1 to 5.1 micron is shown. A series of photometric measurements is reported that may lay the foundation for long-term searches for variations in the albedos. Low-resolution spectra of Ganymede, Callisto, and Europa are also reported along with marginal detections of Neptune at 4.8 micron and two 4.8 micron observations of Uranus.

  10. Efficient resonantly pumped 2.8-micron Er(3+):GSGG laser

    NASA Astrophysics Data System (ADS)

    Stoneman, R. C.; Esterowitz, L.

    1992-06-01

    Efficient CW operation of the Er(3+):GSGG (I-4) 11/2 - (I-4) 13/2 laser transition at 2.8 microns is demonstrated at room temperature. The (I-4) 11/2 upper laser state is directly pumped at 0.97 microns. The slope efficiency for the 2.8-micron laser is 36 percent, indicating a greater than unity quantum efficiency. This excess efficiency results from the recycling of population through upconversion out of the lower laser state.

  11. Emission and extinction of ground and vapor-condensed silicates from 4 to 14 microns and the 10 micron silicate feature

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.; Rusell, R. W.

    1979-01-01

    Emission and absorption spectra from 4 to 14 microns of ground and laser-vaporized olivine and enstatite silicates are compared with the 10-micron emission feature of the Orion Trapezium. The agreement in band center and shape between the amorphous laser-vaporized olivine sample and the Trapezium feature suggests that amorphous silicate grains of approximately olivine composition may be a major constituent of interstellar dust. Differences between the emission and absorption spectral profiles (absorption plus scattering) show characteristics that could be used as a sensitive probe of the morphology of interstellar grain systems when high signal-to-noise ratio (30-100) observational spectra become available.

  12. 2-Micron Laser Transmitter for Coherent CO2 DIAL Measurement

    NASA Technical Reports Server (NTRS)

    Singh, Upendra N.; Bai, Yingxin; Yu, Jirong

    2009-01-01

    Carbon dioxide (CO2) has been recognized as one of the most important greenhouse gases. It is essential for the study of global warming to accurately measure the CO2 concentration in the atmosphere and continuously record its variation. A high repetition rate, highly efficient, Q-switched 2-micron laser system as the transmitter of a coherent differential absorption lidar for CO2 measurement has been developed in NASA Langley Research Center. This laser system is capable of making a vertical profiling of CO2 from ground and column measurement of CO2 from air and space-borne platform. The transmitter is a master-slave laser system. The master laser operates in a single frequency, either on-line or off-line of a selected CO2 absorption line. The slave laser is a Q-switched ring-cavity Ho:YLF laser which is pumped by a Tm:fiber laser. The repetition rate can be adjusted from a few hundred Hz to 10 kHz. The injection seeding success rate is from 99.4% to 99.95%. For 1 kHz operation, the output pulse energy is 5.5mJ with the pulse length of 50 ns. The optical-to-optical efficiency is 39% when the pump power is 14.5W. A Ho:YLF laser operating in the range of 2.05 micrometers can be tuned over several characteristic lines of CO2 absorption. Experimentally, a diode pumped Ho:Tm:YLF laser has been successfully used as the transmitter of coherent differential absorption lidar for the measurement of CO2 with a repetition rate of 5 Hz and pulse energy of 75 mJ. For coherent detection, high repetition rate is required for speckle averaging to obtain highly precise measurements. However, a diode pumped Ho:Tm:YLF laser can not operate in high repetition rate due to the large heat loading and up-conversion. A Tm:fiber laser pumped Ho:YLF laser with low heat loading can operate in high repetition rate. A theoretical model has been established to simulate the performance of Tm:fiber laser pumped Ho:YLF lasers. For continuous wave (CW) operation, high pump intensity with small beam

  13. Transformation and Release of Micronized Cu used as a Wood Preservative in Treated Wood in Wetland Soil

    EPA Science Inventory

    Micronized Cu (µ-Cu) is used as a wood preservative, replacing toxic Chromated Copper Arsenates. Micronized Cu is Malachite [Cu2CO3(OH)2] that has been milled to micron/submicron particles, many with diameters less than 100 nm, and then mixed with quat or azol biocides. I...

  14. Formation of micron and submicron structures on a zirconium oxide surface exposed to nanosecond laser radiation

    SciTech Connect

    Ganin, D V; Mikolutskiy, S I; Khomich, V Yu; Yamshchikov, V A; Tokarev, V N; Shmakov, V A

    2014-04-28

    Possibility of forming quasi-periodic structures of micron and submicron dimensions on a surface of zirconium dioxide under the action of eximer ArF laser radiation is shown experimentally and theoretically. (interaction of laser radiation with matter)

  15. Dust emission features in 3-micron spectra of Herbig Ae/Be stars

    NASA Technical Reports Server (NTRS)

    Brooke, T. Y.; Tokunaga, A. T.; Strom, S. E.

    1993-01-01

    Attention is given to low- and medium-resolution spectra in the 3-micron region of 24 Herbig Ae/Be stars obtained in a search for organic features from the dust around young stars. The 3.29-micron emission feature from aromatic hydrocarbons was detected in three objects: Lk H-alpha 25, XY Per, and AS 310. Two other stars, HD 245185 and HK Ori, may have weak features. About 20 percent of the Herbig Ae/Be surveyed to date have firmly detected 3.29-micron features. The available data indicate that the 3.29-micron feature is more extended around Herbig Ae/Be stars of earlier spectral type, possibly due to dehydrogenization or destruction of the aromatics near these stars. It is suggested that the total number of aromatics excited by the stars is also greater around the earlier-type objects.

  16. A Master-Oscillator-Power-Amplifier 2-micron Laser Using Fiber Phase-conjugate Mirror

    NASA Technical Reports Server (NTRS)

    Yu, Jirong; Bai, Yingxin; Shkunov, V.; Rockwell, D.; Betin, A.; Wang, J.; Petros, M.; Petzar, Paul; Trieu, Bo

    2007-01-01

    For the first time, a 2-micron master-oscillator-power-amplifier laser using a fiber based phase conjugation mirror has been demonstrated. The beam quality improvement and 56% of the PCM reflectivity have been achieved.

  17. Observations of the 145.5 micron (OI) emission line in the Orion nebula

    NASA Technical Reports Server (NTRS)

    Stacey, G. J.; Smyers, S. D.; Kurtz, N. T.; Harwit, M.

    1982-01-01

    A first set of observations of the (OI) 3P to 3P1 (145.5 micron) transition was obtained. The line was observed both in a beam centered on the Trapezium, and in a 7 times wider beam encompassing most of the Orion Nebula. A wide beam map of the region was constructed which shows that most of the emission is confined to the central regions of the nebula. These observations may be compared with reported measurement of the 3P1 to 3P2 (63.2 micron) transition in Orion and are consistent with optically thin emission in the 145.5 micron line and self-adsorbed 63.2 micron emission lines. Mechanisms are discussed for the excitation of neutral oxygen. It is included that much of the observed emission originates in the thin, radio-recombination-line-emitting CII/HI envelope bordering on the HII region.

  18. 2-Micron Pulsed Direct Detection IPDA Lidar for Atmospheric CO2 Measurement

    NASA Technical Reports Server (NTRS)

    Yu, Jirong; Petros, Mulugeta; Refaat, Tamer; Reithmaier, Karl; Remus, Ruben; Singh, Upendra; Johnson, Will; Boyer, Charlie; Fay, James; Johnston, Susan; Murchison, Luke

    2014-01-01

    A 2-micron high energy, pulsed Integrated Path Differential Absorption (IPDA) lidar has been developed for atmospheric CO2 measurements. Development of this lidar heavily leverages the 2-micron laser technologies developed in LaRC over the last decade. The high pulse energy, direct detection lidar operating at CO2 2-micron absorption band provides an alternate approach to measure CO2 concentrations. This new 2-micron pulsed IPDA lidar has been flown in spring of this year for total ten flights with 27 flight hours. It is able to make measurements of the total amount of atmospheric CO2 from the aircraft to the ground or cloud. It is expected to provide high-precision measurement capability by unambiguously eliminating contamination from aerosols and clouds that can bias the IPDA measurement.

  19. Bench-scale testing of a micronized magnetite, fine-coal cleaning process

    SciTech Connect

    Suardini, P.J.

    1995-11-01

    Custom Coals, International has installed and is presently testing a 500 lb/hr. micronized-magnetite, fine-coal cleaning circuit at PETC`s Process Research Facility (PRF). The cost-shared project was awarded as part of the Coal Preparation Program`s, High Efficiency Preparation Subprogram. The project includes design, construction, testing, and decommissioning of a fully-integrated, bench-scale circuit, complete with feed coal classification to remove the minus 30 micron slimes, dense medium cycloning of the 300 by 30 micron feed coal using a nominal minus 10 micron size magnetite medium, and medium recovery using drain and rinse screens and various stages and types of magnetic separators. This paper describes the project circuit and goals, including a description of the current project status and the sources of coal and magnetite which are being tested.

  20. Quenched carbonaceous composite. III - Comparison to the 3.29 micron interstellar emission feature

    NASA Technical Reports Server (NTRS)

    Sakata, A.; Wada, S.; Onaka, T.; Tokunaga, A. T.

    1990-01-01

    Laboratory data are presented showing that oxidized f-QCC, after heating to 500 C, has a 3.29 micron absorption feature that matches precisely the wavelength of the 3.29 micron interstellar emission feature. In addition, the width of the f-QCC (filmy quenched carbonaceous composite) feature is close to that of the 3.29 micron emission feature observed in NGC 7027, Orion, and IRAS 21282 + 5050. Laboratory spectra of polycyclic aromatic hydrocarbons (PAHs) were also obtained, and comparison of the f-QCC and PAH absorption spectra to that of the 3.29 micron emission feature indicates that the f-QCC provides a much better match. It is thus suggested that f-QCC is representative of the class of material giving rise to the emission features in the interstellar medium.

  1. Preparation of multiparticulate systems for oral delivery of a micronized or nanosized poorly soluble drug.

    PubMed

    Cerea, Matteo; Pattarino, Franco; Foglio Bonda, Andrea; Palugan, Luca; Segale, Lorena; Vecchio, Carlo

    2016-09-01

    The purpose of the present work was to prepare multiparticulate drug delivery systems for oral administration of a poorly soluble drug such as itraconazole. Multiparticulate systems were prepared by extrusion/spheronization technique using a mix of crospovidone, low viscosity hypromellose, microcrystalline cellulose, micronized drug and water. In order to improve the release performance of the multiparticulate systems, the micronized drug was suspended in water with polysorbate 20 and nanonized by a high-pressure homogenization. The suspension of drug nanoparticles was then spray-dried for enabling an easy handling of the drug and for preventing the over-wetting of the powders during extrusion/spheronization processing. Both multiparticulate units prepared with micronized or nanonized drug showed acceptable disintegrating properties. The nanosizing of micronized drug powder provided a significant improvement of drug dissolution rates of the multiparticulates. PMID:26786555

  2. 3,7,10,14,15-pentaacetyl-5-butanoyl-13,17-epoxy-8-myrsinene a novel compound isolated from Pycnocycla spinosa extract with potent anti-spasmodic and antidiarrheal properties

    PubMed Central

    Sadraei, H.; Ghanadian, M.; Asghari, G.; Sharifian, R.

    2015-01-01

    Bioassay monitoring of hydroalcoholic extract from the aerial part of Pyconcycla spinosa revealed that it contains components with spasmolytic activity in vitro. In addition, P. spinosa extract at oral dose of 1-5 mg/kg inhibits diarrhoea in animal models. Pharmacological screening of pure compounds isolated from P. spinosa hydroalcoholic extract led to the identification of 3,7,10,14,15-pentaacetyl-5-butanoyl-13,17-epoxy-8-myrsinene (PABEM) which is a new diterpene. In this research, we have investigated antispasmodic and antidiarrheal effects of PABEM for comparison with P. spinosa extract. Aerial parts of P. spinosa were extracted with ethanol. For antispasmodic studies, rat isolated ileum was suspended in Tyrode's solution in an organ bath. The ileum was contracted by acetylcholine (ACh, 0.5 μM), serotonin (5-HT, 5 μM) or electrical field stimulation (EFS). P. spinosa extract in a concentration dependent manner (10-640 μg/ml) inhibited ileum contractions induced by ACh, 5-HT or EFS. The new compound isolated form P. spinosa extract “PABEM” in a similar manner inhibited the contractile response to ACh, 5-HT and EFS. However, the inhibitory effects of PABEM were observed at much lower bath concentrations. The relaxation effect of PABEM was started at 40 ng/ml bath concentration and with 2.5 μg/ml PABEM in the bath, the contractile responses of ileum were completely abolished. Both hydroalcoholic extract of P. spinosa and PABEM reduced intestinal meal transit and castor oil and MgSO4 induced diarrhoea in mice. However, PABEM was about 10 times more potent than its parent extract. This research shows that PABEM is probably the main component responsible for antispasmodic and antidiarrheal actions of P. spinosa extract. PMID:26430457

  3. Preparation and characterization of micronized artemisinin via a Rapid Expansion of Supercritical Solutions (RESS) Method.

    PubMed

    Yu, Huimin; Zhao, Xiuhua; Zu, Yuangang; Zhang, Xinjuan; Zu, Baishi; Zhang, Xiaonan

    2012-01-01

    The particle sizes of pharmaceutical substances are important for their bioavailability. Bioavailability can be improved by reducing the particle size of the drug. In this study, artemisinin was micronized by the rapid expansion of supercritical solutions (RESS). The particle size of the unprocessed white needle-like artemisinin particles was 30 to 1200 μm. The optimum micronization conditions are determined as follows: extraction temperature of 62 °C, extraction pressure of 25 MPa, precipitation temperature 45 °C and nozzle diameter of 1000 μm. Under the optimum conditions, micronized artemisinin with a (mean particle size) MPS of 550 nm is obtained. By analysis of variance (ANOVA), extraction temperature and pressure have significant effects on the MPS of the micronized artemisinin. The particle size of micronized artemisinin decreased with increasing extraction temperature and pressure. Moreover, the SEM, LC-MS, FTIR, DSC and XRD allowed the comparison between the crystalline initial state and the micronization particles obtained after the RESS process. The results showed that RESS process has not induced degradation of artemisinin and that processed artemisinin particles have lower crystallinity and melting point. The bulk density of artemisinin was determined before and after RESS process and the obtained results showed that it passes from an initial density of 0.554 to 0.128 g·cm(-3) after the processing. The decrease in bulk density of the micronized powder can increase the liquidity of drug particles when they are applied for medicinal preparations. These results suggest micronized powder of artemisinin can be of great potential in drug delivery systems. PMID:22606030

  4. Derivation of midinfrared (5-25 microns) optical constants of some silicates and palagonite

    NASA Technical Reports Server (NTRS)

    Roush, T.; Pollack, J.; Orenberg, J.

    1991-01-01

    The 5-25 micron real and imaginary refraction indices are presented for palagonite and the silicates pyrophyllite, kaolinite, serpentine, montmorillonite, saponite, and orthopyroxene. Optical constants in the region of the H2O-bending fundamental near 6 microns are obtained for saponite, montmorillonite, and palagonite. It is established that, if a pellet of pure material can be polished to a mirror finish, the optical constants of such noncohesive materials as clays are easily derivable.

  5. The Carnegie Hubble Program: The Leavitt Law at 3.6 microns and 4.5 microns in the Large Magellanic Cloud

    NASA Technical Reports Server (NTRS)

    Scowcroft, Victoria; Freedman, Wendy L.; Madore, Barry F.; Monson, Andrew J.; Persson, S. E.; Seibert, Mark; Rigby, Jane R.; Sturch, Laura

    2011-01-01

    The Carnegie Hubble Program (CHP) is designed to improve the extragalactic distance scale using data from the post-cryogenic era of Spitzer. The ultimate goal is a determination of the Hubble constant to an accuracy of 2%. This paper is the first in a series on the Cepheid population of the Large Magellanic Cloud, and focuses on the period-luminosity relations (Leavitt laws) that will be used, in conjunction with observations of Milky Way Cepheids, to set the slope and zero-point of the Cepheid distance scale in the mid-infrared. To this end, we have obtained uniformly-sampled light curves for 85 LMC Cepheids, having periods between 6 and 140 days. Period- luminosity and period-color relations are presented in the 3.6 micron and 4.5 micron bands. We demonstrate that the 3.6 micron band is a superb distance indicator. The cyclical variation of the [3.6]-[4.5] color has been measured for the first time. We attribute the amplitude and phase of the color curves to the dissociation and recombination of CO molecules in the Cepheid s atmosphere. The CO affects only the 4.5 micron flux making it a potential metallicity indicator.

  6. Advanced 2-micron Solid-state Laser for Wind and CO2 Lidar Applications

    NASA Technical Reports Server (NTRS)

    Yu, Jirong; Trieu, Bo C.; Petros, Mulugeta; Bai, Yingxin; Petzar, Paul J.; Koch, Grady J.; Singh, Upendra N.; Kavaya, Michael J.

    2006-01-01

    Significant advancements in the 2-micron laser development have been made recently. Solid-state 2-micron laser is a key subsystem for a coherent Doppler lidar that measures the horizontal and vertical wind velocities with high precision and resolution. The same laser, after a few modifications, can also be used in a Differential Absorption Lidar (DIAL) system for measuring atmospheric CO2 concentration profiles. The world record 2-micron laser energy is demonstrated with an oscillator and two amplifiers system. It generates more than one joule per pulse energy with excellent beam quality. Based on the successful demonstration of a fully conductive cooled oscillator by using heat pipe technology, an improved fully conductively cooled 2-micron amplifier was designed, manufactured and integrated. It virtually eliminates the running coolant to increase the overall system efficiency and reliability. In addition to technology development and demonstration, a compact and engineering hardened 2-micron laser is under development. It is capable of producing 250 mJ at 10 Hz by an oscillator and one amplifier. This compact laser is expected to be integrated to a lidar system and take field measurements. The recent achievements push forward the readiness of such a laser system for space lidar applications. This paper will review the developments of the state-of-the-art solid-state 2-micron laser.

  7. New long-wavelength Nd:YAG laser at 1. 44 micron: effect on brain

    SciTech Connect

    Martiniuk, R.; Bauer, J.A.; McKean, J.D.; Tulip, J.; Mielke, B.W.

    1989-02-01

    A wavelength-shifted Nd:YAG laser, tuned to coincide with the infrared absorption peak of water at 1.44 microns, was used to make lesions in normal rabbit brain. A total of 48 lesions were made with power up to 20 W, with energy up to 40 joules, and with two different spot sizes. These lesions were compared to lesions made with 1.06 microns radiation from an Nd:YAG laser under identical operating conditions. Measurements of blood-brain barrier damage and width, depth, and volume of tissue affected were obtained 30 minutes after placement of the lesions. It was found that 1.44-microns lesions produced photoevaporative tissue loss at the highest intensities used. The layer of coagulated tissue remaining after photovaporization had a mean thickness of 0.6 mm irrespective of the volume of tissue removed. There was no photovaporization in the 1.06-microns lesions. In addition, the amount of peripheral edema per unit volume of tissue coagulated was approximately half at the 1.44-microns wavelength. These findings suggest that the 1.44-microns Nd:YAG laser may be a useful surgical instrument since it combines the photoevaporative effect of the CO/sub 2/ laser while maintaining the advantages of the conventional Nd:YAG laser (quartz fiber delivery and effective hemostasis).

  8. Measurement of spectral, directional reflectivities of solids at high temperatures between 9 and 11 microns

    NASA Astrophysics Data System (ADS)

    Roy, Subhransu; Bang, Se Y.; Modest, Michael F.; Stubican, Vladimir S.

    1993-07-01

    A new apparatus to measure spectral, directional reflectivities of solids for temperatures up to 1100 C is developed. Reflectivities of two ceramic materials, silicon nitride (Si3N4) and silicon carbide alpha-SiC, are measured at wavelengths between 9 and 11 microns (the operating range of tunable CO2 lasers) for various temperatures, angles of incidence, and for two types of polarization, the electric vector perpendicular and parallel to the plane of incidence. Reflectivities are measured by comparing the power of the beam reflected from the sample (heated in the furnace) with that of the incident beam. This experimental setup is limited to relatively specular surfaces (with a collection half-angle of 15 deg). The measurements show that the reflectivity of alpha-SiC at room temperature rises sharply near about 10.2 microns because of the presence of a 12.6-micron reflection band (restrahlen band), and the occurrence of this phenomenon gradually shifts to longer wavelengths as the temperature is raised to 1000 C. At 10.6 microns, where most CO3 lasers operate, the reflectivity of SiC diminishes rapidly as the temperature is raised. Si3N4 has two restrahlen bands on both sides of 9.9 microns at room temperature that gradually shift to longer wavelengths with temperature. However, the decrease in reflectivity of Si3N4 with temperature at 10.6 microns is very small.

  9. Preliminary evaluation of a pulsed 2.15-micron laser system for fiberoptic endoscopic surgery.

    PubMed

    Treat, M R; Trokel, S L; Reynolds, R D; DeFilippi, V J; Andrew, J; Liu, J Y; Cohen, M G

    1988-01-01

    There is a need for lasers that are compatible with fiberoptic endoscopes and that provide greater cutting precision than currently can be produced by the widely used Nd:YAG (1.06 micron) laser. Recently available lasers that operate in the 2-micron region fill this need. This laser light energy can be transmitted by low OH- silica fibers and has much less tissue penetration than radiation at 1.06 micron. We have been evaluating a prototype solid state laser system that produces pulses of 2.15 microns light that is delivered by a silica based fiberoptic delivery system with negligible transmission losses. This system is based on a thulium-holmium-chromium doped YAG (Tm-Ho-Cr: YAG) rod that lases at 2.15 micron. The laser does not require cryogenic cooling, toxic gases, or custom utilities and should be practical in a clinical environment. In vivo animal testing of this laser confirms that it provides greater ablating precision than does the Nd:YAG laser at 1.06 micron. PMID:2839746

  10. New long-wavelength Nd:YAG laser at 1.44 micron: effect on brain.

    PubMed

    Martiniuk, R; Bauer, J A; McKean, J D; Tulip, J; Mielke, B W

    1989-02-01

    A wavelength-shifted Nd:YAG laser, tuned to coincide with the infrared absorption peak of water at 1.44 microns, was used to make lesions in normal rabbit brain. A total of 48 lesions were made with power up to 20 W, with energy up to 40 joules, and with two different spot sizes. These lesions were compared to lesions made with 1.06 microns radiation from an Nd:YAG laser under identical operating conditions. Measurements of blood-brain barrier damage and width, depth, and volume of tissue affected were obtained 30 minutes after placement of the lesions. It was found that 1.44-microns lesions produced photoevaporative tissue loss at the highest intensities used. The layer of coagulated tissue remaining after photovaporization had a mean thickness of 0.6 mm irrespective of the volume of tissue removed. There was no photovaporization in the 1.06-microns lesions. In addition, the amount of peripheral edema per unit volume of tissue coagulated was approximately half at the 1.44-microns wavelength. These findings suggest that the 1.44-microns Nd:YAG laser may be a useful surgical instrument since it combines the photoevaporative effect of the CO2 laser while maintaining the advantages of the conventional Nd:YAG laser (quartz fiber delivery and effective hemostasis). PMID:2913222

  11. Observations of the 51.8 micron forbidden O III emission line in Orion

    NASA Technical Reports Server (NTRS)

    Melnick, G.; Gull, G. E.; Harwit, M.; Ward, D. B.

    1978-01-01

    This letter reports observations of the 51.8-micron fine-structure transition p2: 3P(2) - 3P(1) for doubly ionized oxygen. The observed line strength in the Orion Nebula is (5 + or - 3) by 10 to the -15th power W/sq cm, in good agreement with the theoretical predictions of Simpson (1975). The observations are also consistent with the predicted line position, 51.8 microns. The line lies close to an atmospheric water-vapor feature at 51.7 microns but is sufficiently distant so that corrections for this feature are straightforward. Observations of the 51.8-micron forbidden O III line are particularly important, since the previously discovered 88-micron line from the same ion also is strong. This pair of lines should therefore yield new data about densities in observed H II regions; or else, if density data already are available from radio or other observations, the lines can be used to determine the differential dust absorption between 52 and 88 microns in front of heavily obscured regions.

  12. 2-micron Pulsed Direct Detection IPDA Lidar for Atmospheric CO2 Measurements

    NASA Astrophysics Data System (ADS)

    Yu, J.; Singh, U.; Petros, M.

    2012-12-01

    A 2-micron high energy, pulsed Integrated Path Differential Absorption (IPDA) lidar is being developed for atmospheric CO2 measurements. Development of this lidar heavily leverages the 2-micron laser technologies developed in LaRC over the last decade. The high pulse energy, direct detection lidar operating at CO2 2-micron absorption band provides an alternate approach to measure CO2 concentrations with significant advantages. It is expected to provide high-precision measurement capability by unambiguously eliminating contamination from aerosols and clouds that can bias the IPDA measurement. Our objective is to integrate an existing high energy double-pulsed 2-micron laser transmitter with a direct detection receiver and telescope to enable an airborne capability to perform a first proof of principle demonstration of airborne direct detection CO2 measurements. The 2-micron transmitter provides 100mJ at 10Hz with double pulse format specifically designed for DIAL/IPDA instrument. The compact, rugged, highly reliable transceiver is based on unique Ho:Tm:YLF high-energy 2-micron pulsed laser technology. All the optical mounts are custom designed and have space heritage. A 16-inch diameter telescope has been designed and being manufactured for the direct detection lidar. The detector is an InGaAs Positive-Intrinsic-Negative (PIN) photodiode manufactured by Hamamatsu Corporation. The performance of the detector is characterized at various operating temperatures and bias voltages for spectral response, NEP, response time, dynamic range, and linearity. A collinear lidar structure is designed to be integrated to NASA UC12 or B200 research aircrafts. This paper will describe the design of the airborne 2-micron pulsed IPDA lidar system; the lidar operation parameters; the wavelength pair selection; laser transmitter energy, pulse rate, beam divergence, double pulse generation and accurate frequency control; detector characterization; telescope design; lidar structure design

  13. Spectral Anomalies in the 11 and 12 micron Region From the Mariner Mars 7 Infrared Spectrometer

    NASA Technical Reports Server (NTRS)

    Kirkland, Laurel E.; Herr, Kenneth C.

    2000-01-01

    Two hundred-forty infrared spectra acquired by the 1969 Mariner Mars 7 Infrared Spectrometer (IRS), spanning the wavelength region 1.8-14.4 micron (5550-690/cm), have recently been recovered and calibrated in both wavelength and intensity. An examination of these IRS spectra has revealed absorptions at 11.25 and 12.5 micron that have not previously been reported for Mars. A search of the literature and spectral data bases shows that materials that exhibit a doublet at 11.25 and 12.5 micron are rare. In this paper we examine potential causes for these features and include a detailed discussion of carbonates, goethite, CO2 ice, and water ice. CO2 ice and water ice measured in transmission do not exhibit bands that match those recorded at 11.25 and 12.5 micron for Mars, which indicates that CO2 or water ice clouds are not the source of these features. Since these bands show no clear correlation with atmospheric path length, they are most likely caused by a surface material. In the IRS database they appear to be exceptionally intense in the western part of the Hellas basin. Goethite exhibits bands that are a good spectral match, but confirming whether goethite causes the features will require additional studies of the 20-50 micron region. These studies will require laboratory measurements of weathering coatings and an examination of spectra recorded of Mars by the 1971 Mariner Mars Infrared Interferometer Spectrometer (IRIS; 5-50 micron 2000200/cm) and the 1996 Thermal Emission Spectrometer (TES; 6-50 micron 1667-200/cm).

  14. Radiative Properties of Cirrus Clouds in the Infrared (8-13 microns) Spectral Region

    NASA Technical Reports Server (NTRS)

    Yang, Ping; Gao, Bo-Cai; Baum, Bryan A.; Hu, Yong X.; Wiscombe, Warren J.; Tsay, Si-Chee; Winker, Dave M.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    Atmospheric radiation in the infrared (IR) 8-13 microns spectral region contains a wealth of information that is very useful for the retrieval of ice cloud properties from aircraft or space-borne measurements. To provide the scattering and absorption properties of nonspherical ice crystals that are fundamental to the IR retrieval implementation, we use the finite-difference time domain (FDTD) method to solve for the extinction efficiency, single-scattering albedo, and the asymmetry parameter of the phase function for ice crystals smaller than 40 microns. For particles larger than this size, the improved geometric optics method (IGOM) can be employed to calculate the asymmetry parameter with an acceptable accuracy, provided that we properly account for the inhomogeneity of the refracted wave due to strong absorption inside the ice particle. A combination of the results computed from the two methods provides the asymmetry parameter for the entire practical range of particle sizes between 1 micron and 10000 microns over wavelengths ranging from 8 microns to 13 microns. For the extinction and absorption efficiency calculations, several methods including the IGOM, Mie solution for equivalent spheres (MSFES), and the anomalous diffraction theory (ADT) can lead to a substantial discontinuity in comparison with the FDTD solutions for particle sizes on the order of 40 microns. To overcome this difficulty, we have developed a novel approach called the stretched scattering potential method (SSPM). For the IR 8-13 microns spectral region, we show that SSPM is a more accurate approximation than ADT, MSFES, and IGOM. The SSPM solution can be further refined numerically. Through a combination of the FDTD and SSPM, we have computed the extinction and absorption efficiency for hexagonal ice crystals with sizes ranging from 1 to 10000 microns at 12 wavelengths between 8 and 13 microns Calculations of the cirrus bulk scattering and absorption properties are performed for 30 size

  15. Development of megapixel HgCdTe detector arrays with 15 micron cutoff

    NASA Astrophysics Data System (ADS)

    Forrest, William J.; McMurtry, Craig W.; Dorn, Meghan L.; Pipher, Judith; Cabrera, Mario S.

    2016-06-01

    I. HistoryHgCdTe is a versatile II-VI semiconductor with a direct-bandgap tunable via the Hg:Cd ratio. Hg:Cd ratio = 53:47 (2.5 micron cutoff) was used on the NICMOS instrument on HST and the 2MASS. Increasing Hg:Cd ratio to 70:30 leads to a 5.4 micron cutoff, utilized in NEOWISE and many JWST instruments. Bailey, Wu et al. (1998) motivated extending this technology to 10 microns and beyond. Bacon, McMurtry et al. (2003, 2004) indicated significant progress toward this longwave (LW) goal.Warm-Spitzer has pioneered passive cooling to below 30 K in space, enabling the JWST mission.II. CurrentNASA's proposed NEOcam mission selected HgCdTe with a 10.6 micron cutoff because it promises natural Zodiacal background limited sensitivity with modest cooling (40 K). Teledyne Imaging Systems (TIS) is producing megapixel arrays with excellent performance (McMurtry, Lee, Dorn et al. (2013)) for this mission.III. FutureModest cooling requirements (circa 30 K) coupled with megapixel arrays and LW sensitivity in the thermal IR make HgCdTe attractive for many infrared instruments. For instance, the spectral signature of a terrestrial planet orbiting in the habitable zone of a nearby star will be the deep and wide absorption by CO_2 centered at 15 microns (Seager and Deming, 2010). LW instruments can enhance Solar System missions, such as exploration of the Enceladus geysers (Spencer, Buratti et al. 2006). Passive cooling will be adequate for these missions. Modern ground-based observatories will benefit from infrared capability out to the N band (7.5-13.6 microns). The required detector temperatures (30-40 K) are easily achievable using commercially available mechanical cryo-coolers (refrigerators).IV. Progress to dateTIS is developing megapixel HgCdTe arrays sensitive out to 15 microns under the direction of the University of Rochester. As a first step, we have produced arrays with a 13 micron cutoff. The initial measurements indicate very promising performance. We will present the

  16. Micron-scale plasma membrane curvature is recognized by the septin cytoskeleton.

    PubMed

    Bridges, Andrew A; Jentzsch, Maximilian S; Oakes, Patrick W; Occhipinti, Patricia; Gladfelter, Amy S

    2016-04-11

    Cells change shape in response to diverse environmental and developmental conditions, creating topologies with micron-scale features. Although individual proteins can sense nanometer-scale membrane curvature, it is unclear if a cell could also use nanometer-scale components to sense micron-scale contours, such as the cytokinetic furrow and base of neuronal branches. Septins are filament-forming proteins that serve as signaling platforms and are frequently associated with areas of the plasma membrane where there is micron-scale curvature, including the cytokinetic furrow and the base of cell protrusions. We report here that fungal and human septins are able to distinguish between different degrees of micron-scale curvature in cells. By preparing supported lipid bilayers on beads of different curvature, we reconstitute and measure the intrinsic septin curvature preference. We conclude that micron-scale curvature recognition is a fundamental property of the septin cytoskeleton that provides the cell with a mechanism to know its local shape. PMID:27044896

  17. Progress of 2-micron Detectors for Application to Lidar Remote Sensing

    NASA Technical Reports Server (NTRS)

    Abedin, M. N.; Refaat, Tamer F.; Ismail, Syed; Koch, Grady; Singh, Upendra N.

    2008-01-01

    AlGaAsSb/InGaAsSb heterojunction phototransistors were developed at Astropower, Inc under Laser Risk Reduction Program (LRRP) for operation in the 2-micron region. These phototransistors were optimized for 2-micron detection and have high quantum efficiency (>60%), high gain (>10(exp 3)) and low noise-equivalent- power (<5x10(exp -14) W/Hz), while operating at low bias voltage. One of these phototransistors was tested in lidar mode using the 2-micron CO2 Differential Absorption Lidar (DIAL) system currently under development under the Instrument Incubator Program (IIP) at NASA Langley. Lidar measurements included detecting atmospheric structures consisting of thin clouds in the mid-altitude and near-field boundary layer. These test results are very promising for the application of phototransistors for the two-micron lidar remote sensing. In addition, HgCdTe avalanche photodiodes (APD) acquired from Raytheon were used in atmospheric testing at 2-microns. A discussion of these measurements is also presented in this paper.

  18. Unraveling the 10 micron "silicate" feature of protostars: the detection of frozen interstellar ammonia

    NASA Technical Reports Server (NTRS)

    Lacy, J. H.; Faraji, H.; Sandford, S. A.; Allamandola, L. J.

    1998-01-01

    We present infrared spectra of four embedded protostars in the 750-1230 cm-1 (13.3-8.1 microns) range. For NGC 7538 IRS 9, a new band is reported at 1110 cm-1 (9.01 microns, and several others may be present near 785, 820, 900, 1030, and 1075 cm-1 (12.7, 12.2, 11.1, 9.71, and 9.30 microns). The band 1110 cm-1 is attributed to frozen NH3. Its position and width imply that the NH3 is frozen in a polar, H2O-rich interstellar ice component. The NH3/H2O ice ratio inferred for NGC 7538 IRS 9 is 0.1, making NH3 as important a component as CH3OH and CO2 in the polar ices along this line of sight. At these concentrations, hydrogen bonding between the NH3 and H2O can account for much of the enigmatic low-frequency wing on the 3240 cm-1 (3.09 microns) H2O interstellar ice band. The strength of the implied NH3 deformation fundamental at 1624 cm-1 (6.158 microns) can also account for the absorption at this position reported by ISO.

  19. The influence of relative humidity on the cohesion properties of micronized drugs used in inhalation therapy.

    PubMed

    Young, Paul M; Price, Robert; Tobyn, Michael J; Buttrum, Mark; Dey, Fiona

    2004-03-01

    The influence of relative humidity (RH) on the cohesion properties of three drugs: salbutamol sulphate (SS), triamcinolone acetonide (TAA), and disodium cromoglycate (DSCG) was investigated using the atomic force microscope (AFM) colloidal probe technique. Micronized drug particles were mounted in heat-sensitive epoxy resin for immobilization. Multiple AFM force-distance curves were conducted between each drug probe and the immobilized drug particulates at 15, 45, and 75% RH using Force-Volume imaging. Clear variations in the cohesion profile with respect to RH were observed for all three micronized drugs. The calculated force and energy of cohesion to separate either micronized SS or DSCG increased as humidity was raised from 15 to 75% RH, suggesting capillary forces become a dominating factor at elevated RH. In comparison, the separation force and energy for micronized TAA particles decreased with increased RH. This behavior may be attributed to long-range attractive electrostatic interactions, which were observed in the approach cycle of the AFM force-distance curves. These observations correlated well with previous aerosolization studies of the three micronized drugs. PMID:14762913

  20. 2-Micron Coherent Doppler Lidar Instrument Advancements for Tropospheric Wind Measurement

    NASA Technical Reports Server (NTRS)

    Petros, Mulugeta; Singh, U. N.; Yu, J.; Kavaya, M. J.; Koch, G.

    2014-01-01

    Knowledge derived from global tropospheric wind measurement is an important constituent of our overall understanding of climate behavior [1]. Accurate weather prediction saves lives and protects properties from destructions. High-energy 2-micron laser is the transmitter of choice for coherent Doppler wind detection. In addition to the eye-safety, the wavelength of the transmitter suitably matches the aerosol size in the lower troposphere. Although the technology of the 2-micron laser has been maturing steadily, lidar derived wind data is still a void in the global weather database. In the last decade, researchers at NASA Langley Research Center (LaRC) have been engaged in this endeavor, contributing to the scientific database of 2-micron lidar transmitters. As part of this effort, an in depth analysis of the physics involved in the workings of the Ho: Tm laser systems have been published. In the last few years, we have demonstrated lidar transmitter with over1Joule output energy. In addition, a large body of work has been done in characterizing new laser materials and unique crystal configurations to enhance the efficiency and output energy of the 2-micron laser systems. At present 2-micron lidar systems are measuring wind from both ground and airborne platforms. This paper will provide an overview of the advancements made in recent years and the technology maturity levels attained.