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1

Experimental Study of Hypernuclei Electroproduction by High Precision Spectroscopy  

SciTech Connect

Jlab experiment E01-011, carried out in 2005 in JLab Hall C, is the second generation of the hypernuclear spectroscopy experiments by the (e,e{prime}K{sup +}) reaction. The (e,e{prime}K{sup +}) reaction is complimentary to the associated production reactions (K{sup -},{pi}{sup -}), ({pi}{sup +},K{sup +}) since, due to a larger momentum transfer to a hyperon, excitations of both spin-non-flip and spin-flip states are possible. The experiment uses high quality and continuous primary electron beam to produce neutron rich hypernuclei on various targets by the electroproduction. The experimental setup consists of splitter magnet, high resolution kaon spectrometer (HKS) and electron spectrometer (Enge) implemented in new configuration, the so called 'Tilt Method'. Production data was taken on multiple targets: CH{sub 2}, {sup 6}Li, {sup 7}Li, {sup 9}Be, {sup 10}B, {sup 12}C and {sup 28}Si. In present study the analysis of CH{sub 2}, {sup 12}C and {sup 28}Si is presented. The elementary processes of p(e,e{prime}K{sup +}){Lambda}/{Sigma} from CH{sup 2} data were used for calibration of the spectrometer optics and kinematics. The hypernuclear spectra of {sup 12}{sub {Lambda}}B was obtained with ground state resolution of 0.47 {+-} 0.07 MeV (FWHM), the best ever achieved. Feasibility of the electroproduction reaction to study medium to heavy targets has been proven with the first high resolution beyond p-shell hypernuclear spectra from {sup 28}{sub {Lambda}}Al hypernuclei. The obtained results of the E01-011 experiment confirmed that hypernuclear spectroscopy by the (e,e{prime}K{sup +}) reaction is a very useful technique.

Tomislav Seva

2009-12-01

2

Modelling and experimental investigation of spindle and cutter dynamics for a high-precision machining center  

Microsoft Academic Search

The geometric quality of high-precision parts is highly dependent on the dynamic performance of the entire machining system, which is determined by the interrelated dynamics of machine tool mechanical structure and cutting process. This performance is of great importance in advanced, high-precision manufacturing processes, including aerospace and biomedical applications. In this paper, the dynamics of the combined spindle\\/cutter system, a

Adam G. Rehorn; Jin Jiang; Peter E. Orban; Evgueni Bordatchev

2004-01-01

3

MEASUREMENT AND PRECISION, EXPERIMENTAL VERSION.  

ERIC Educational Resources Information Center

|THIS DOCUMENT IS AN EXPERIMENTAL VERSION OF A PROGRAMED TEXT ON MEASUREMENT AND PRECISION. PART I CONTAINS 24 FRAMES DEALING WITH PRECISION AND SIGNIFICANT FIGURES ENCOUNTERED IN VARIOUS MATHEMATICAL COMPUTATIONS AND MEASUREMENTS. PART II BEGINS WITH A BRIEF SECTION ON EXPERIMENTAL DATA, COVERING SUCH POINTS AS (1) ESTABLISHING THE ZERO POINT,…

Harvard Univ., Cambridge, MA. Harvard Project Physics.

4

High precision fiber development  

Microsoft Academic Search

The improvement of single-mode precision fiber is critical to the efficient use of these fibers in connectors and to allow for low loss splices. Similarly, the alignment of fibers to integrated optic devices demands high precision. Likewise, the precision of large core multimode fibers affects coupler and connector losses as well as overall optical and physical performance. In accordance with

F. I. Akers; H. D. Shepherd

1981-01-01

5

High precision fiber development  

NASA Astrophysics Data System (ADS)

The improvement of single-mode precision fiber is critical to the efficient use of these fibers in connectors and to allow for low loss splices. Similarly, the alignment of fibers to integrated optic devices demands high precision. Likewise, the precision of large core multimode fibers affects coupler and connector losses as well as overall optical and physical performance. In accordance with the statement of work (SOW), EOPD has evaluated the parameters that affect the fabrication of high precision 100 micrometer core fiber and single-mode precision fiber. ITT EOPD has completed the full dimensional evaluation of precision shrunk, ground, and polished natural fused quartz tubing. Additionally, ITT has verified the od uniformity of precision shrunk, ground, and polished Vycor brand silica glass tubing. Fibers made from preforms utilizing the above substrates met all requirements of this contract. The large core deliverable had a fiber od of 140 micrometers with a fiber core diameter of 100.1 micrometers, well within the limits of the contract. Other measurements showed the core eccentricity to be less than 0.08%; optical loss at 0.85 micrometers was 7.94 dB/km while the NA was 0.29. Measurements of the low NA deliverable revealed an average NA of 0.11, an od of 80.5 micrometers, and a core eccentricity of 0.20%. For the high NA fiber, the NA value ran 0.20; the od was the same as the low NA, 80.5 micrometers, while the core eccentricity ran less than 0.20%.

Akers, F. I.; Shepherd, H. D.

1981-01-01

6

Highly precise experimental device for determining the heat capacity of liquids under pressure  

NASA Astrophysics Data System (ADS)

An experimental device for making isobaric heat capacity measurements of liquids under pressure is presented. The device is an adaptation of the Setaram micro-DSC II atmospheric-pressure microcalorimeter, including modifications of vessels and a pressure line allowing the pressure in the measurement system to be set, controlled, and stabilized. The high sensitivity of the apparatus combined with a suitable calibration procedure allows very accurate heat capacity measurements under pressure to be made. The relative uncertainty in the isobaric molar heat capacity measurements provided by the new device is estimated to be 0.08% at atmospheric pressure and 0.2% at higher levels. The device was validated from isobaric molar heat capacity measurements for hexane, nonane, decane, undecane, dodecane, and tridecane, all of which were highly consistent with reported data. It also possesses a high sensitivity as reflected in its response to changes in excess isobaric molar heat capacity with pressure, which were examined in this work for the first time by making heat capacity measurements throughout the composition range of the 1-hexanol+n-hexane system. Finally, preliminary measurements at several pressures near the critical conditions for the nitromethane+2-butanol binary system were made that testify to the usefulness of the proposed device for studying critical phenomena in liquids under pressure.

González-Salgado, D.; Valencia, J. L.; Troncoso, J.; Carballo, E.; Peleteiro, J.; Romaní, L.; Bessières, D.

2007-05-01

7

Highly precise experimental device for determining the heat capacity of liquids under pressure  

SciTech Connect

An experimental device for making isobaric heat capacity measurements of liquids under pressure is presented. The device is an adaptation of the Setaram micro-DSC II atmospheric-pressure microcalorimeter, including modifications of vessels and a pressure line allowing the pressure in the measurement system to be set, controlled, and stabilized. The high sensitivity of the apparatus combined with a suitable calibration procedure allows very accurate heat capacity measurements under pressure to be made. The relative uncertainty in the isobaric molar heat capacity measurements provided by the new device is estimated to be 0.08% at atmospheric pressure and 0.2% at higher levels. The device was validated from isobaric molar heat capacity measurements for hexane, nonane, decane, undecane, dodecane, and tridecane, all of which were highly consistent with reported data. It also possesses a high sensitivity as reflected in its response to changes in excess isobaric molar heat capacity with pressure, which were examined in this work for the first time by making heat capacity measurements throughout the composition range of the 1-hexanol+n-hexane system. Finally, preliminary measurements at several pressures near the critical conditions for the nitromethane+2-butanol binary system were made that testify to the usefulness of the proposed device for studying critical phenomena in liquids under pressure.

Gonzalez-Salgado, D.; Valencia, J. L.; Troncoso, J.; Carballo, E.; Peleteiro, J.; Romani, L.; Bessieres, D. [Departamento de Fisica Aplicada, Facultad de Ciencias de Ourense, As Lagoas s/n, 32004 Ourense (Spain); Laboratoire de Fluides Complexes, Groupe Haute Pression, Universite de Pau et des Pays de l'Adour, BP 1155, 64013 Pau (France)

2007-05-15

8

Design and experimental research of a high-precision wavelength controller for tunable fiber Fabry-Perot filters  

NASA Astrophysics Data System (ADS)

A high-precision wavelength controller is presented in this paper. It is necessary to find out the difference between the central wavelength of a tunable fiber Fabry-Perot (FFP) filter and that of the input laser, while the wavelength controller operates at the states of wavelength-scanning and wavelength-locking modes. Firstly, a dynamic simulation model of tunable FFP filter is established, and the dynamic characteristic of tunable FFP filter modulated by an alternating current (AC) signal is simulated. Then the measuring time at wavelength-scanning mode compared with the theory time is discussed, and this time difference shows the difference between the central wavelength of a tunable FFP filter and that of the input laser. At last, the effects on wavelength-locking precision of time delays, including the time delay of opened-loop circuit, the time constant of the closed-loop circuit and the intrinsic hysteresis of piezoelectric (PZT) element, are analyzed. A wavelength controller of tunable FFP filter is designed and prepared. The experimental results at wavelength-locking mode show that a high locking precision is obtained.

Qi, Hai-bing; Wei, Shu-hua; Wei, Chen

2013-03-01

9

High precision cochleostomy by use of a pulsed CO2 laser - an experimental approach.  

PubMed

A precise cochleostomy is a crucial step in cochlear implantation, particularly if residual hearing is to be preserved. A contactless ablation of the promontory bone by a pulsed CO(2) laser system seems to be a promising approach. The bone is removed by a scan head controlled laser beam in sequential scan cycles with a pulse rate of 50-100 mus. Digital picture analysis and pattern detection are used to identify the membranous lining of the cochlea. We achieved a bone ablation in a micrometer range per scan cycle with the laser. A perforation of the promontory bone could be detected by automatic pattern detection. The enhancement of automatic pattern detection can lead to a minimally invasive, function-preserving laser cochleostomy. PMID:19194966

Klenzner, Thomas; Knapp, Felix B; Schipper, Joerg; Raczkowsky, Joerg; Woern, Heinz; Kahrs, Lueder A; Werner, Martin; Hering, Peter

2009-01-01

10

Experimental access to higher-order Zeeman effects by precision spectroscopy of highly charged ions in a Penning trap  

NASA Astrophysics Data System (ADS)

We present an experimental concept and setup for laser-microwave double-resonance spectroscopy of highly charged ions in a Penning trap. Such spectroscopy allows a highly precise measurement of the Zeeman splittings of fine- and hyperfine-structure levels due the magnetic field of the trap. We have performed detailed calculations of the Zeeman effect in the framework of quantum electrodynamics of bound states as present in such highly charged ions. We find that apart from the linear Zeeman effect, second- and third-order Zeeman effects also contribute to the splittings on a level of 10-4 and 10-8, respectively, and hence are accessible to a determination within the achievable spectroscopic resolution of the ARTEMIS experiment currently in preparation.

von Lindenfels, D.; Wiesel, M.; Glazov, D. A.; Volotka, A. V.; Sokolov, M. M.; Shabaev, V. M.; Plunien, G.; Quint, W.; Birkl, G.; Martin, A.; Vogel, M.

2013-02-01

11

Flexures for high precision robotics  

Microsoft Academic Search

High precision robots are often used for complex assembly or positioning tasks. One way to achieve high motion precision is to design mechanical systems based on flexure joints. Flexure joints (or flexures) utilize the elastic properties of matter, which brings avoidance of dry friction. Nanometer scale motions are then possible, without wear, mechanical play or particle emission. Leading to high

Jean-Philippe Bacher; Cédric Joseph; Reymond Clavel

2002-01-01

12

Experimental Investigations of Signals of a New Nature with the aid of two High Precision Stationary Quartz Gravimeters  

Microsoft Academic Search

In consequence of long-term (2000) observation of a system of two high-precision quartz gravimeters (one of them with an attached magnet) placed in a special (at a depth of $\\\\sim $10m) gravimetric laboratory on a common base separated from the foundation of the building, signals of a new nature were detected. They were of a smooth peak-type shape, several minutes

Yu. A. Baurov; A. V. Kopajev

2001-01-01

13

Highly Parallel, High-Precision Numerical Integration  

SciTech Connect

This paper describes a scheme for rapidly computing numerical values of definite integrals to very high accuracy, ranging from ordinary machine precision to hundreds or thousands of digits, even for functions with singularities or infinite derivatives at endpoints. Such a scheme is of interest not only in computational physics and computational chemistry, but also in experimental mathematics, where high-precision numerical values of definite integrals can be used to numerically discover new identities. This paper discusses techniques for a parallel implementation of this scheme, then presents performance results for 1-D and 2-D test suites. Results are also given for a certain problem from mathematical physics, which features a difficult singularity, confirming a conjecture to 20,000 digit accuracy. The performance rate for this latter calculation on 1024 CPUs is 690 Gflop/s. We believe that this and one other 20,000-digit integral evaluation that we report are the highest-precision non-trivial numerical integrations performed to date.

Bailey, David H.; Borwein, Jonathan M.

2005-04-22

14

Experimental investigation on focusing characteristics of a He-Ne laser using circular Fresnel zone plate for high-precision alignment of linear accelerators  

SciTech Connect

We experimentally investigate the focusing characteristics of a He-Ne laser at the focal region for the high-precision alignment of long-distance linear accelerators using a circular Fresnel zone plate. The laser wave passing through the Fresnel zone plate having a focal length of 66.7 m propagates for a 268-m-long distance at atmospheric pressure. A new laser-based alignment system using Fresnel zone plates as the alignment targets is discussed. The transverse displacement of the focused spot of the laser is measured as a function of the displacement of the target by a detector installed at the focal point. Systematic studies on the focusing characteristics and alignment precision have been successfully conducted in this experiment. The experimental results are in good agreement with theoretical calculations, and the alignment precision of the target is determined to be less than {+-}30 {mu}m. In this study, we perform a detailed experimental investigation on the laser propagation and focusing characteristics using the circular Fresnel zone plate at the focal region along with theoretical calculations.

Suwada, Tsuyoshi; Satoh, Masanori [Accelerator Laboratory, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Telada, Souichi; Minoshima, Kaoru [Length Standards Section, Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8563 (Japan)

2012-05-15

15

EXPERIMENTAL MEASUREMENT OF PRECISION BEARING DYNAMIC STIFFNESS  

Microsoft Academic Search

Static stiffness measurement of precision bearing components by influence coefficients is complicated by the task of loading and measuring the baseline test fixture stiffness before including the bearing components. Furthermore, as the displacement of the bearing system is measured for various load conditions, the stiffness of high quality bearings may be difficult to distinguish from the test fixture stiffness. The

E. R. Marsh; D. S. Yantek

1997-01-01

16

High precision positioning with a sensor network  

Microsoft Academic Search

We present an experimental high-precision ultrasonic positioning system based on a sensor network. The network can track an object moving along a straight line with an accuracy of 1 cm. The bulk of the position calculation is distributed, with sensor nodes exchanging only the times-of-flight of the ultrasonic pulses, and state information.

Julio I. Concha; Jae-Hyuk Oh

2004-01-01

17

High Precision Pressure Measurement with a Funnel  

ERIC Educational Resources Information Center

|A simple experimental device for high precision differential pressure measurements is presented. Its working mechanism recalls that of a hydraulic press, where pressure is supplied by insufflating air under a funnel. As an application, we measure air pressure inside a soap bubble. The soap bubble is inflated and connected to a funnel which is…

Lopez-Arias, T.; Gratton, L. M.; Oss, S.

2008-01-01

18

High Precision CCD Imaging Polarimetry  

NASA Astrophysics Data System (ADS)

We describe a recent modification to the direct CCD Cameras at CTIO and LNA (Brazil) observatories in order to allow for high precision optical polarimetry. We make use of a rotating achromatic half-wave plate as a retarder and a Savart plate as analyser. Cancellation of sky polarization and independence of the CCD flat field correction are among the advantages of the arrangement. We show preliminary data that indicate the high polarimetric precision achievable with the method for non-extended sources. We give a brief description of the on-going observational programs employing the technique. Polarimetry of extended objects can be performed by using a Polaroid sheet in place of the Savart plate. Use of the Savart plate with such fields can also be valuable in the reduction, and analysis, of the extended source images as it provides polarization data on the non-extended objects in the field.

Magalhaes, A. M.; Rodrigues, C. V.; Margoniner, V. E.; Pereyra, A.; Heathcote, S.; Coyne, G. V.

1994-12-01

19

High precision localization of bacteria  

NASA Astrophysics Data System (ADS)

A small variation of bacterium size has great impact on their ability to cope with the new environment. This variation is not traceable in bacterium images as they may be less than a pixel width. In this paper, we present a method for high precision localization and dimension estimation of bacteria in microscopic images. Experiments on simulated data, shows that our method can achieve more accurate estimation of bacterium dimension in comparing with state-of-the-art sub-pixel cell outlining tool.

Hosseini, Mohammadreza; Sowmya, Arcot; Vallotton, Pascal; Bednarz, Tomasz

2013-10-01

20

A high temperature precision amplifier  

SciTech Connect

A precision operational amplifier has been developed for instrumentation applications in which the circuitry must operate in ambient temperatures as high as 200 C. At 200 C the amplifier maintains an input offset voltage and current of less than 200 {mu}V and 1 nA respectively, a gain bandwidth product of 2.2 MHz, and a slew rate of 5.4 V/{mu}S. The amplifier is fabricated in a standard CMOS process and consumes 5.5 mW of power at a supply voltage of 5 V. A continuous time auto-zeroed amplifier topology is used to achieve the low offset voltage levels. At high temperatures the leakage currents of the sample and hold switches used to achieve auto-zeroing degrade the offset correction voltages stored on the hold capacitors. This degradation is reduced by using large external hold capacitors and by minimizing the diffusion area of the switches through the use of a doughnut shaped layout. The effect of the voltage degradation is reduced by sensing the offset correction voltage with a low sensitivity differential auxiliary input stage. A new input switch topology is used to reduce the amplifier`s input offset current at high temperatures.

Finvers, I.G.; Haslett, J.W.; Trofimenkoff, F.N. [Univ. of Calgary, Alberta (Canada). Dept. of Electrical and Computer Engineering

1995-02-01

21

High precision triangular waveform generator  

DOEpatents

An ultra-linear ramp generator having separately programmable ascending and descending ramp rates and voltages is provided. Two constant current sources provide the ramp through an integrator. Switching of the current at current source inputs rather than at the integrator input eliminates switching transients and contributes to the waveform precision. The triangular waveforms produced by the waveform generator are characterized by accurate reproduction and low drift over periods of several hours. The ascending and descending slopes are independently selectable.

Mueller, Theodore R. (Oak Ridge, TN)

1983-01-01

22

High precision Standard Model Physics  

NASA Astrophysics Data System (ADS)

The main goal of the LHCb experiment, one of the four large experiments of the Large Hadron Collider, is to try to give answers to the question of why Nature prefers matter over antimatter? This will be done by studying the decay of b quarks and their antimatter partners, b, which will be produced by billions in 14 TeV p-p collisions by the LHC. In addition, as ``beauty'' particles mainly decay in charm particles, an interesting program of charm physics will be carried on, allowing to measure quantities as for instance the D0-D0 mixing, with incredible precision.

Magnin, J.

2009-04-01

23

High precision Standard Model Physics  

SciTech Connect

The main goal of the LHCb experiment, one of the four large experiments of the Large Hadron Collider, is to try to give answers to the question of why Nature prefers matter over antimatter? This will be done by studying the decay of b quarks and their antimatter partners, b-bar, which will be produced by billions in 14 TeV p-p collisions by the LHC. In addition, as 'beauty' particles mainly decay in charm particles, an interesting program of charm physics will be carried on, allowing to measure quantities as for instance the D{sup 0}-D-bar{sup 0} mixing, with incredible precision.

Magnin, J. [Brazilian Center for Reserach in Physics-CBPF Rua Dr. Xavier Sigaud 150-URCA, CEP 22290-180, Rio de Janeiro (Brazil)

2009-04-20

24

High Precision Sampling for Chromatographic Separations.  

National Technical Information Service (NTIS)

The precision of several chromatographic sampling values of original design is shown to approach plus or minus 0.05% for unretained solutes. Hybrid-fluidic, high pressure, and commercial valves have been characterized by measuring the precision of their c...

B. E. Bowen S. P. Cram J. E. Leitner R. L. Wade

1973-01-01

25

Precision electroweak physics at high energies  

NASA Astrophysics Data System (ADS)

The era of precision electroweak measurements at high energies started twenty years ago with the electron-positron colliders LEP and SLC. Excellent performance of accelerators, advanced detectors and precise theoretical predictions led to enormous progress in the examination of the Standard Model. Ongoing measurements at the Tevatron complement the precision results from LEP and SLC and allow a comprehensive test of the electroweak interactions. So far, the Standard Model has agreed well with the measurements and no significant deviation has been observed. But the Higgs boson, an important constituent of the Standard Model, has not yet been found but its mass is constrained by the high precision data. In this report an overview of the global electroweak tests of the Standard Model is presented. It includes the measurements, and their treatment to probe the Standard Model with highest precision. Finally, a short outlook to physics scenarios beyond the Standard Model is given.

Riemann, Sabine

2010-12-01

26

Analysis of High Precision Composite Sandwich Antennas.  

National Technical Information Service (NTIS)

A data base for all common types of spacecraft antenna skin and core materials was established. Based on these material properties, it is possible to predict accurately the performance of high precision antennas, and there is good agreement between analys...

G. Helwig

1986-01-01

27

Coherent detection circuit for high precision encoders  

Microsoft Academic Search

Robots and industrial machines today requires high precision of 0.1 ?m, high speed of 30-60 m\\/min, and durability for position sensing. Moreover, being compact in size and low in price is indispensable for practical applications. Inductosyn scale is one of the most widely used position sensors. It can attain either required precision or speed, however, not both of them at

Masanobu Mizoguchi; T. Matsukawa; K. Takeuchi; T. Fukuda

2000-01-01

28

Experimental Study of a Precision, Hydrodynamic Wheel Spindle for Submicron Cylindrical Grinding  

Microsoft Academic Search

Hydrodynamic journal bearings have been widely used in various types of rotating machinery, ranging from heavy duty, high-impact applications, such as the crank shaft of an internal combustion engine and turbine rotor, to high-precision, light load applications, such as precision spindles in cylindrical grinding machines. Although extensive theoretical and experimental results have been presented for hydrodynamic bearings, the available literature

J. F. Tu; M. Corless; M. J. Gehrich; A. J. Shih

1998-01-01

29

Compact design for high precision machine tools  

Microsoft Academic Search

Due to raising functional integration in micro fluidic, micro mechanic, micro electronic and micro optical systems the trend to scaling down the work piece sizes while increasing its complexity requires high precise machine accuracy. With respect to the process and geometrical parameters, most of the finishing manufacturing processes can be covered by milling and grinding operations with three or five

C. Brecher; P. Utsch; R. Klar; C. Wenzel

2010-01-01

30

Design of a high precision current source  

Microsoft Academic Search

Current source is one of the key components in electrical measurement and control systems. However, the noise introduced by temperature drift and other interference makes it a significant source of systematic errors. To develop a high precision and stable current source, a Howland-based voltage to current conversion (V\\/I) circuit is presented in this paper. The current source is fully programmable

Yu Peng; Yanchao Xia; Shaojun Wang

2009-01-01

31

Automatic titrator for high precision plutonium assay  

SciTech Connect

Highly precise assay of plutonium metal is required for accountability measurements. We have developed an automatic titrator for this determination which eliminates analyst bias and requires much less analyst time. The analyst is only required to enter sample data and start the titration. The automated instrument titrates the sample, locates the end point, and outputs the results as a paper tape printout. Precision of the titration is less than 0.03% relative standard deviation for a single determination at the 250-mg plutonium level. The titration time is less than 5 min.

Jackson, D.D.; Hollen, R.M.

1986-01-01

32

DURIP95/Ultra High Precision Diagnostic High Temperature Laboratory.  

National Technical Information Service (NTIS)

The DURIP grant was used to develop an efficient high temperature laboratory with high precision instruments to make deformation and load measurements in high temperature materials including advanced composites. The laboratory has been successfully develo...

G. M. Newaz

1997-01-01

33

Portable high precision pressure transducer system  

NASA Astrophysics Data System (ADS)

A high precision pressure transducer system for checking the reliability of a second pressure transducer system used to monitor the level of a fluid confined in a holding tank is presented. Since the response of the pressure transducer is temperature sensitive, it is continually housed in a battery powered oven which is configured to provide a temperature stable environment at specified temperature for an extended period of time. Further, a high precision temperature stabilized oscillator and counter are coupled to a single board computer to accurately determine the pressure transducer oscillation frequency and convert it to an applied pressure. All of the components are powered by the batteries which during periods of availability of line power are charged by an on-board battery charger. The pressure readings outputs are transmitted to a line printer and a vacuum fluorescent display.

Piper, T. C.; Morgan, J. P.; Marchant, N. J.; Bolton, S. M.

34

Portable high precision pressure transducer system  

DOEpatents

A high precision pressure transducer system for checking the reliability of a second pressure transducer system used to monitor the level of a fluid confined in a holding tank. Since the response of the pressure transducer is temperature sensitive, it is continually housed in an battery powered oven which is configured to provide a temperature stable environment at specified temperature for an extended period of time. Further, a high precision temperature stabilized oscillator and counter are coupled to a single board computer to accurately determine the pressure transducer oscillation frequency and convert it to an applied pressure. All of the components are powered by the batteries which during periods of availability of line power are charged by an on board battery charger. The pressure readings outputs are transmitted to a line printer and a vacuum florescent display.

Piper, Thomas C. (Idaho Falls, ID); Morgan, John P. (Idaho Falls, ID); Marchant, Norman J. (Idaho Falls, ID); Bolton, Steven M. (Pocatello, ID)

1994-01-01

35

Portable high precision pressure transducer system  

DOEpatents

A high precision pressure transducer system is described for checking the reliability of a second pressure transducer system used to monitor the level of a fluid confined in a holding tank. Since the response of the pressure transducer is temperature sensitive, it is continually housed in an battery powered oven which is configured to provide a temperature stable environment at specified temperature for an extended period of time. Further, a high precision temperature stabilized oscillator and counter are coupled to a single board computer to accurately determine the pressure transducer oscillation frequency and convert it to an applied pressure. All of the components are powered by the batteries which during periods of availability of line power are charged by an on board battery charger. The pressure readings outputs are transmitted to a line printer and a vacuum fluorescent display. 2 figures.

Piper, T.C.; Morgan, J.P.; Marchant, N.J.; Bolton, S.M.

1994-04-26

36

Portable high precision pressure transducer system  

DOEpatents

A high precision pressure transducer system for checking the reliability of a second pressure transducer system used to monitor the level of a fluid confined in a holding tank. Since the response of the pressure transducer is temperature sensitive, it is continually housed in an battery powered oven which is configured to provide a temperature stable environment at specified temperature for an extended period of time. Further, a high precision temperature stabilized oscillator and counter are coupled to a single board computer to accurately determine the pressure transducer oscillation frequency and convert it to an applied pressure. All of the components are powered by the batteries which during periods of availability of line power are charged by an on board battery charger. The pressure readings outputs are transmitted to a line printer and a vacuum florescent display.

Piper, T.C.; Morgan, J.P.; Marchant, N.J.; Bolton, S.M.

1992-12-31

37

Measurement and Precision: High School Activity  

NSDL National Science Digital Library

This activity from the Florida Advanced Technological Education (FL-ATE) Center asks students to use the concepts of measurement and precision in the context of designing and manufacturing surgical instruments. The interdisciplinary lesson plan involves science, computer technology, math and technical education. Students will have the opportunity to develop their understanding of number systems and their application in the context of a practical industrial situation. This version of the lesson is appropriate for high school aged students.

2013-06-13

38

Precision mass measurements of highly charged ions  

NASA Astrophysics Data System (ADS)

The reputation of Penning trap mass spectrometry for accuracy and precision was established with singly charged ions (SCI); however, the achievable precision and resolving power can be extended by using highly charged ions (HCI). The TITAN facility has demonstrated these enhancements for long-lived (T1/2>=50 ms) isobars and low-lying isomers, including ^71Ge^21+, ^74Rb^8+, ^78Rb^8+, and ^98Rb^15+. The Q-value of ^71Ge enters into the neutrino cross section, and the use of HCI reduced the resolving power required to distinguish the isobars from 3 x 10^5 to 20. The precision achieved in the measurement of ^74Rb^8+, a superallowed ?-emitter and candidate to test the CVC hypothesis, rivaled earlier measurements with SCI in a fraction of the time. The 111.19(22) keV isomeric state in ^78Rb was resolved from the ground state. Mass measurements of neutron-rich Rb and Sr isotopes near A = 100 aid in determining the r-process pathway. Advanced ion manipulation techniques and recent results will be presented.

Kwiatkowski, A. A.; Bale, J. C.; Brunner, T.; Chaudhuri, A.; Chowdhury, U.; Ettenauer, S.; Frekers, D.; Gallant, A. T.; Grossheim, A.; Lennarz, A.; Mane, E.; MacDonald, T. D.; Schultz, B. E.; Simon, M. C.; Simon, V. V.; Dilling, J.

2012-10-01

39

Recent high precision surveys at PEP  

SciTech Connect

The task of surveying and aligning the components of PEP has provided an opportunity to develop new instruments and techniques for the purpose of high precision surveys. The new instruments are quick and easy to use, and they automatically encode survey data and read them into the memory of an on-line computer. When measurements of several beam elements have been taken, the on-line computer analyzes the measured data, compares them with desired parameters, and calculates the required adjustments to beam element support stands.

Sah, R.C.

1980-12-01

40

Research about the high precision temperature measurement  

NASA Astrophysics Data System (ADS)

High precision temperature control system is one of most important support conditions for tunable birefringent filter.As the first step,we researched some high precision temperature measurement methods for it. Firstly, circuits with a 24 bit ADC as the sensor's reader were carefully designed; Secondly, an ARM porcessor is used as the centrol processing unit, it provides sufficient reading and procesing ability; Thirdly, three kinds of sensors, PT100, Dale 01T1002-5 thermistor, Wheatstone bridge(constructed by pure copper and manganin) as the senor of the temperature were tested respectively. The resolution of the measurement with these three kinds of sensors are all better than 0.001 that's enough for 0.01 stability temperature control. Comparatively, Dale 01T1002-5 thermistor could get the most accurate temperature of the key point, Wheatstone bridge could get the most accurate mean temperature of the whole layer, both of them will be used in our futrue temperature controll system.

Lin, J.; Yu, J.; Zhu, X.; Zeng, Z.; Deng, Y.

2012-12-01

41

High efficiency francium trap for precision spectroscopy  

NASA Astrophysics Data System (ADS)

We cooled and trapped francium in a high efficiency magneto-optical trap. The francium is produced artificially in a nuclear fusion reaction using the Stony Brook superconducting LINAC. We observed an average trap population of 50,000 210Fr, corresponding to a trapping efficiency of 1.2%. The trapped atoms are cooled to a temperature of 75 muK. We used the new trapping apparatus for spectroscopic studies of the 9S 1/2 level of 210Fr to test the precision of atomic theory. We measured the hyperfine splitting of the 9S1/2 level, and with time-correlated single photon counting, we measured its radiative lifetime. We found a lifetime of 107.53 +/- 0.80 ns and a hyperfine splitting of 4045.1 +/- 1.1 MHz. We characterized the optical properties of a dipole trap based on an axicon lens to provide a low perturbation environment for precision spectroscopy. The axicon generates a region of darkness surrounded by light. For blue-detuned light, cold atoms are trapped in the dark region and experience almost no perturbing fields. This work continues the spectroscopic studies of francium for tests of atomic theory and opens the way for nuclear anapole moment measurements.

Aubin, Seth Andre Morgan

42

Highly damped kinematic coupling for precision instruments  

DOEpatents

A highly damped kinematic coupling for precision instruments. The kinematic coupling provides support while causing essentially no influence to its nature shape, with such influences coming, for example, from manufacturing tolerances, temperature changes, or ground motion. The coupling uses three ball-cone constraints, each combined with a released flexural degree of freedom. This arrangement enables a gain of higher load capacity and stiffness, but can also significantly reduce the friction level in proportion to the ball radius divided by the distance between the ball and the hinge axis. The blade flexures reduces somewhat the stiffness of the coupling and provides an ideal location to apply constrained-layer damping which is accomplished by attaching a viscoelastic layer and a constraining layer on opposite sides of each of the blade flexures. The three identical ball-cone flexures provide a damped coupling mechanism to kinematically support the projection optics system of the extreme ultraviolet lithography (EUVL) system, or other load-sensitive apparatus.

Hale, Layton C. (Livermore, CA); Jensen, Steven A. (Livermore, CA)

2001-01-01

43

High precision calculation of helium and atom energy levels  

SciTech Connect

This work is concerned with the high-presicion calculation of the energies of the gound and excited states of the helium atom (or other light helium-like ions) to match the recent advances in experimental laser spectroscopic studies of transitions between these states with a precision of better than 10{sup {minus}4} cm{sup {minus}1}. At this level of accuracy it is essential to include mass-polarization effects through 2nd order, relativistic effects properly scaled by appropriate powers of the reduced mass, and quantum electrodynamic (QED) effects. In recent work on excited states of helium we have attained this level of accuracy for all the non-QED effects. Our results are in good agreement with those obtained independently by G. W. F. Drake. We are proceeding with a high-precision evaluation of the Bethe logarithm, which is the principal source of uncertainty in the theoretically determined QED effects. The refinement of these calculations at the 10{sup {minus}5} cm{sup {minus}1} level and beyond is expectd to stimulate further advances both theoretical and experimental, both in the calculations of 0({alpha}{sup 4}) Rydberg relativistic and QED effects and in the high-precision measurement of transition wavelengths.

Baker, J.; Hill, R.N.; Morgan, J.D. III (Department of Physics, University of Delaware, Newark, DE 19716 (USA))

1989-06-15

44

Experimental Violation of Heisenberg's Precision Limit by Weak Measurements  

NASA Astrophysics Data System (ADS)

Along with the uncertainty principle, Heisenberg postulated another set of relations, which set a lower limit on the disturbance caused by a measurement [1]. These relations were shown by Ozawa to be inaccurate [2], shedding doubt on widely accepted bounds on the information left in a system after a measurement, and offering new insights into the foundations of quantum physics and quantum information. A theoretical scheme for testing Ozawa's precision-disturbance relations was proposed [3]. In this proposal the hurdle of destructive measurements is addressed by the weak value approach [4]. This scheme is based on a 3-qubit quantum circuit that requires two CNOT gates of variable strength with a common control qubit. Here, we present an experimental realization of Heisenberg's precision limit violation based on weak value measurements. We implement a technique inspired by the one-way quantum computing using entanglement as the substrate for quantum gates. In this way, we demonstrate a violation of Heisenberg's relation for measurement disturbance, confirming the revised bound due to Ozawa. [4pt] [1] Z. Phys. 43 172(1927); [2] Ann. Phys. NY 311 350(2004); [3] New J. Phys. 12 093011(2010); [4] Phys. Rev. Lett. 60 1351(1988)

Darabi, Ardavan; Rozema, Lee A.; Mahler, Dylan H.; Hayat, Alex; Soudagar, Yasaman; Steinberg, Aephraim M.

2012-02-01

45

Experimental study on lawn sprinkler for energy-saving and variable range of the precision spraying  

Microsoft Academic Search

For solving the problem of high energy consumption of variable nozzle, the experimental study on lawn sprinkler for energy-saving and variable range of the precision spraying were carried out. In the case of square spraying, the functions of control period between nozzle inlet pressure, converter frequency and time were determined by tests. The motor frequency was regulated by the converter;

Yue Tang; Junping Liu; Yin Luo; Shouqi Yuan

2010-01-01

46

Improved technique for high precision FSR measurement  

NASA Astrophysics Data System (ADS)

It is critical to know the free spectral range (FSR) of an etalon for telecommunication applications. In this paper, we have improved the Pound-Drever-Hall (PDH) based technique for measuring the FSR of an etalon by 2 orders of magnitude. This improved technique results 1 part in 106 precision. To our knowledge this is the most precise measurement of FSR.

Ozdur, Ibrahim; Ozharar, Sarper; Quinlan, Franklyn; Gee, Sangyoun; Delfyett, Peter, Jr.

2008-05-01

47

High-Precision Measurement of Tool-Tip Displacement Using Strain Gauges in Precision Flexible Line Boring  

NASA Astrophysics Data System (ADS)

Precision displacement measurement is a critical element to achieve active control for high-precision (e.g. 5 ?m) flexible line boring. Since current measurement methods are difficult to apply in this application, a new measurement method has been developed. This paper presents a new strain-gauge-based method for the high-precision vibration measurement of a beam. This method is based on the fact that the vibration displacement can be expressed in terms of an infinite number of vibration modes and be related to the measured strains through the strain-displacement relationship. By placing multiple sets of strain gauges, multiple modes can be taken into account to achieve high-precision measurement. Both simulation and experimental results were obtained and are provided for validation. From these results, it can be concluded that this new measurement method is applicable to high-precision flexible line boring, enabling active control to compensate for the tool-tip displacement to achieve a high-precision machining process.

Li, Chen-Jung; Ulsoy, A. Galip

1999-07-01

48

Future high precision experiments and new physics beyond Standard Model  

SciTech Connect

High precision (< 1%) electroweak experiments that have been done or are likely to be done in this decade are examined on the basis of Standard Model (SM) predictions of fourteen weak neutral current observables and fifteen W and Z properties to the one-loop level, the implications of the corresponding experimental measurements to various types of possible new physics that enter at the tree or loop level were investigated. Certain experiments appear to have special promise as probes of the new physics considered here.

Luo, Mingxing

1993-04-01

49

Future high precision experiments and new physics beyond Standard Model  

SciTech Connect

High precision (< 1%) electroweak experiments that have been done or are likely to be done in this decade are examined on the basis of Standard Model (SM) predictions of fourteen weak neutral current observables and fifteen W and Z properties to the one-loop level, the implications of the corresponding experimental measurements to various types of possible new physics that enter at the tree or loop level were investigated. Certain experiments appear to have special promise as probes of the new physics considered here.

Luo, Mingxing.

1993-01-01

50

High Precision Measurement of the Neon-19 Lifetime  

NASA Astrophysics Data System (ADS)

The lifetime of 19Ne is an important parameter in precision tests of the Standard Model. Improvement in the uncertainty of experimental observables of this and other T = ½ mirror isotopes would allow for an extraction of Vud at a similar precision to that obtained by superallowed 0+ ? 0 + Fermi decays. We report on a new high precision measurement of the lifetime of 19Ne, performed at the Kernfysich Versneller Instituut (KVI) in Groningen, the Netherlands. A 10.5 MeVA 19F beam was used to produce 19Ne using inverse reaction kinematics in a H2 gas target. Contaminant productions were eliminated using the TRImuP magnetic isotope separator. The 19Ne beam was implanted into a thick aluminum tape, which was translated to a shielded detection region by a custom tape drive system. Collinear annihilation radiation from the emitted decay positrons were detected by two high purity germanium (HPGe) detectors. Event pulse waveforms were digitized and stored using a CAEN V1724 Digitizer. Systematic studies were performed to characterize rate-dependent data acquisition effects, diffusion, backgrounds, and contamination from the separator. We have obtained the result for the lifetime of tau = 24.9344 +/- 0.0073(stat) +/- 0.0083( sys) seconds.

Broussard, Leah Jacklyn

51

Simulations for the NIFFTE High Precision TPC  

NASA Astrophysics Data System (ADS)

The Neutron Induced Fission Fragment Tracking Experiment has designed a Time Projection Chamber (TPC) to measure neutron induced fission cross-section measurements of the major actinides to sub-1% precision over a wide incident neutron energy range. These measurements are necessary to design the next generation of nuclear power plants. In order to design a TPC capable of making these measurements, a precise simulation was required to ensure better track reconstruction. Using the Geometry And Tracking (Geant4) simulation platform along with standalone code, a complete simulation package has been written. Asynchronous trigger, 3-D charge diffusion, capacitive charge sharing, digitization, random trigger cells, and noise from the electronics have been modeled inside the detector response simulation, along with code that generates bi-products of fission events for Geant4. This talk will discuss the current status and future planned developments of this work including the efforts to make this code reusable for future TPC projects.

Thornton, Remington

2010-10-01

52

High Precision Noise Measurements at Microwave Frequencies  

SciTech Connect

We describe microwave noise measurement system capable of detecting the phase fluctuations of rms amplitude of 2{center_dot}10{sup -11} rad/{radical}(Hz). Such resolution allows the study of intrinsic fluctuations in various microwave components and materials, as well as precise tests of fundamental physics. Employing this system we discovered a previously unknown phenomenon of down-conversion of pump oscillator phase noise into the low-frequency voltage fluctuations.

Ivanov, Eugene; Tobar, Michael [School of Physics, University of Western Australia, 35 Stirling Hwy., Crawley, 6009, WA (Australia)

2009-04-23

53

High contrast gratings for high-precision metrology  

NASA Astrophysics Data System (ADS)

Experiments in the field of high-precision optical metrology are crucially limited by thermal noise of the optical components such as mirrors or beam splitters. Amorphous coatings stacks are found to be a main source for these thermal fluctuations. In this contribution we present approaches to realize coating free optical components based on resonant high contrast gratings (HCGs) made of crystalline silicon. It is shown that beside classical cavity mirrors the concept of HCGs can also be used for reflective cavity couplers. We compare the advantages and challenges of these HCG reflectors with distributed Bragg reflectors made of crystalline coatings for applications in optical metrology.

Kroker, Stefanie; Steiner, Stefan; Käsebier, Thomas; Kley, Ernst-Bernhard; Tünnermann, Andreas

2013-03-01

54

High precision measurement system based on coplanar XY-stage  

NASA Astrophysics Data System (ADS)

A coplanar XY-stage, together with a high precise measurement system, is presented in this paper. The proposed coplanar XY-stage fully conforms to the Abbe principle. The symmetric structural design is considered to eliminate the structure deformation due to force and temperature changes. For consisting of a high precise measurement system, a linear diffraction grating interferometer(LDGI) is employed as the position feedback sensor with the resolution to 1 nm after the waveform interpolation, an ultrasonic motor HR4 is used to generate both the long stroke motion and the nano positioning on the same stage. Three modes of HR4 are used for positioning control: the AC mode in continuous motion control for the long stroke; the gate mode to drive the motor in low velocity for the short stroke; and the DC mode in which the motor works as a piezo actuator, enabling accurate positioning of a few nanometers. The stage calibration is carried out by comparing the readings of LDGI with a Renishaw laser interferometer and repeated 5 times. Experimental results show the XY-stage has achieved positioning accuracy in less than 20nm after the compensation of systematic errors, and standard deviation is within 20 nm for travels up to 20 mm.

Fan, Kuang-Chao; Miao, Jin-Wei; Gong, Wei; Zhang, You-Liang; Cheng, Fang

2011-08-01

55

Computation of High-Order Maps to Multiple Machine Precision  

NASA Astrophysics Data System (ADS)

The Beam Dynamics simulation package in COSY INFINITY is built upon a differential algebra data type. With it, it is possible to compute transfer maps or arbitrary systems to arbitrary order. However, this data type is limited by the precision of the underlying floating point number model provided by the computer processor. We will present a method to extend the effective precision of the calculations based purely on standard floating point operations. Those algorithms are then integrated into the differential algebra data type to efficiently extend the available precision, without unnecessarily affecting overall efficiency. To that effect, the precision of each coefficient is adjusted automatically during the calculation. We will then proceed to show the effectiveness of our implementation by calculating high precision maps of combinations of homogeneous dipole segments, for which the exact results are known, and comparing the high precision coefficients with the results produced by the traditional COSY beam physics package.

Wittig, Alexander; Berz, Martin

56

High-precision stereoscopic 3D mapping accuracy  

NASA Astrophysics Data System (ADS)

The state-of-the-art in extremely versatile fine-resolution Synthetic Aperture Radar (SAR) systems allows incredibly fine resolution and accurate images to be formed over a wide range of imaging geometries (squint angles and depression angles). This capability in turn is allowing the fusion of multiple views of targets and scenes into very accurate 3-dimensional renderings of the same scenes and targets. With proper imaging geometry selections, relative height accuracy within a scene can easily be on the order of the resolution of the original SAR images, thereby rivaling the finest IFSARs even on the drawing boards, and without the height ambiguities typically associated with large-baseline IFSARs. Absolute accuracy is typically limited to the accuracy of SAR flight path knowledge, bounded typically by GPS performance. This paper presents the relationship of height accuracy to imaging geometry (flight path) selection, and illustrates conditions for optimum height estimates. Furthermore, height accuracy is related to 3-D position accuracy and precision over a variety of imaging geometries. Performance claims of height precision on the order of resolution are validated with experimental results that are also presented, using multiple aspects of a target scene collected from a high-performance single-phase-center SAR.

Doerry, Armin W.

2001-08-01

57

High-precision anemometer with thermal wave  

SciTech Connect

A new, highly accurate method of measurement of the gas flow velocity has been developed. The method employs the phenomenon of propagation of thermal waves in flowing gas. The probe consists of three thin wires. One of these is a hot wire and it is used to generate a thermal wave while the two remaining wires are used for wave detection. Since the phase shift of the wave between two points is proportional to the wave frequency, the flow velocity can be derived from the slope of the regression line. Signals from the wave detectors are sent via an analog to digital converter to the computer and processed. We report measurements of the laminar flow with the velocity between 30 and 200 cm/s. The accuracy of the velocity measurements is about 0.2 cm/s.

Rachalski, Andrzej [Strata Mechanics Research Institute, Polish Academy of Sciences, uleja Reymonta 27, 30-112 Cracow (Poland)

2006-09-15

58

Research of a High Precision Sodium Pressure Transducer.  

National Technical Information Service (NTIS)

A high precision sodium pressure transducer using the dynamometric annulus as the Sensor is developed. The construction of the transducer, the calculation of the dynamometric annulus, the fixation of the strain gauge, the measurement circuits and the grad...

D. Chen

1986-01-01

59

System and method for high precision isotope ratio destructive analysis  

DOEpatents

A system and process are disclosed that provide high accuracy and high precision destructive analysis measurements for isotope ratio determination of relative isotope abundance distributions in liquids, solids, and particulate samples. The invention utilizes a collinear probe beam to interrogate a laser ablated plume. This invention provides enhanced single-shot detection sensitivity approaching the femtogram range, and isotope ratios that can be determined at approximately 1% or better precision and accuracy (relative standard deviation).

Bushaw, Bruce A; Anheier, Norman C; Phillips, Jon R

2013-07-02

60

High-precision control of linear actuators with nonlinear friction  

Microsoft Academic Search

In recent years, a high-precision stage control has received great attention due to the progress of nano-technology. A fast-response and high-precision control method based on the internal model control in the case where the controlled object has the integral characteristic is reported. The disturbance observer-based internal model control (DIMC) system has the advantages of no-overshoot, easy-design and simple-realization comparing to

Seiji Hashimoto; Yusaku Fujii; Masayuki Kigure

2007-01-01

61

High-precision x-ray spectroscopy of highly charged ions with microcalorimeters  

NASA Astrophysics Data System (ADS)

The precise determination of the energy of the Lyman ?1 and ?2 lines in hydrogen-like heavy ions provides a sensitive test of quantum electrodynamics in very strong Coulomb fields. To improve the experimental precision, the new detector concept of microcalorimeters is now exploited for such measurements. Such detectors consist of compensated-doped silicon thermistors and Pb or Sn absorbers to obtain high quantum efficiency in the energy range of 40-70 keV, where the Doppler-shifted Lyman lines are located. For the first time, a microcalorimeter was applied in an experiment to precisely determine the transition energy of the Lyman lines of lead ions at the experimental storage ring at GSI. The energy of the Ly ?1 line E(Ly-?1, 207Pb81+) = (77937 ± 12stat ± 25syst) eV agrees within error bars with theoretical predictions. To improve the experimental precision, a new detector array with more pixels and better energy resolution was equipped and successfully applied in an experiment to determine the Lyman-? lines of gold ions 197Au78+.

Kraft-Bermuth, S.; Andrianov, V.; Bleile, A.; Echler, A.; Egelhof, P.; Grabitz, P.; Ilieva, S.; Kilbourne, C.; Kiselev, O.; McCammon, D.; Meier, J.

2013-09-01

62

High-precision camera distortion measurements with a "calibration harp".  

PubMed

This paper addresses the high-precision measurement of the distortion of a digital camera from photographs. Traditionally, this distortion is measured from photographs of a flat pattern that contains aligned elements. Nevertheless, it is nearly impossible to fabricate a very flat pattern and to validate its flatness. This fact limits the attainable measurable precisions. In contrast, it is much easier to obtain physically very precise straight lines by tightly stretching good quality strings on a frame. Taking literally "plumb-line methods," we built a "calibration harp" instead of the classic flat patterns to obtain a high-precision measurement tool, demonstrably reaching 2/100 pixel precisions. The harp is complemented with the algorithms computing automatically from harp photographs two different and complementary lens distortion measurements. The precision of the method is evaluated on images corrected by state-of-the-art distortion correction algorithms, and by popular software. Three applications are shown: first an objective and reliable measurement of the result of any distortion correction. Second, the harp permits us to control state-of-the art global camera calibration algorithms: it permits us to select the right distortion model, thus avoiding internal compensation errors inherent to these methods. Third, the method replaces manual procedures in other distortion correction methods, makes them fully automatic, and increases their reliability and precision. PMID:23201661

Tang, Zhongwei; von Gioi, Rafael Grompone; Monasse, Pascal; Morel, Jean-Michel

2012-10-01

63

Precise Experimental Investigation of Eigenmodes in a Planar Ion Crystal  

NASA Astrophysics Data System (ADS)

The accurate characterization of eigenmodes and eigenfrequencies of two-dimensional ion crystals provides the foundation for the use of such structures for quantum simulation purposes. We present a combined experimental and theoretical study of two-dimensional ion crystals. We demonstrate that standard pseudopotential theory accurately predicts the positions of the ions and the location of structural transitions between different crystal configurations. However, pseudopotential theory is insufficient to determine eigenfrequencies of the two-dimensional ion crystals accurately but shows significant deviations from the experimental data obtained from resolved sideband spectroscopy. Agreement at the level of 2.5×10-3 is found with the full time-dependent Coulomb theory using the Floquet-Lyapunov approach and the effect is understood from the dynamics of two-dimensional ion crystals in the Paul trap. The results represent initial steps towards an exploitation of these structures for quantum simulation schemes.

Kaufmann, H.; Ulm, S.; Jacob, G.; Poschinger, U.; Landa, H.; Retzker, A.; Plenio, M. B.; Schmidt-Kaler, F.

2012-12-01

64

Precise experimental investigation of eigenmodes in a planar ion crystal.  

PubMed

The accurate characterization of eigenmodes and eigenfrequencies of two-dimensional ion crystals provides the foundation for the use of such structures for quantum simulation purposes. We present a combined experimental and theoretical study of two-dimensional ion crystals. We demonstrate that standard pseudopotential theory accurately predicts the positions of the ions and the location of structural transitions between different crystal configurations. However, pseudopotential theory is insufficient to determine eigenfrequencies of the two-dimensional ion crystals accurately but shows significant deviations from the experimental data obtained from resolved sideband spectroscopy. Agreement at the level of 2.5×10(-3) is found with the full time-dependent Coulomb theory using the Floquet-Lyapunov approach and the effect is understood from the dynamics of two-dimensional ion crystals in the Paul trap. The results represent initial steps towards an exploitation of these structures for quantum simulation schemes. PMID:23368557

Kaufmann, H; Ulm, S; Jacob, G; Poschinger, U; Landa, H; Retzker, A; Plenio, M B; Schmidt-Kaler, F

2012-12-28

65

High precision sensing system for vibration distribution measurement  

NASA Astrophysics Data System (ADS)

Aimed at the study actuality of displacement distribution measurement of each point on the surface in the micro- motion status, a new vibration displacement distribution interferometry combining sinusoidal phase-modulating(SPM) with Fourier transform is proposed in the paper, its principle and the influence on the measuring precision caused by noise is analyzed in theory. The corresponding interferometer adopting this technique above mentioned was developed The interferometer can be applied into vibration measurement, and vibration distribution measurement. By measuring a mirror's microvibration, the vibration distribution measurement was realized, its repeatable measuring precision was 5.61nm. Experimental results validated the feasibility of the interferometer.

He, Guotian; Tang, Chaowei; Zhao, Lijuan; Fu, Mingyi

2007-11-01

66

An experimental assembly for precise measurement of thermal accommodation coefficients  

NASA Astrophysics Data System (ADS)

An experimental apparatus has been developed to determine thermal accommodation coefficients for a variety of gas-surface combinations. Results are obtained primarily through measurement of the pressure dependence of the conductive heat flux between parallel plates separated by a gas-filled gap. Measured heat-flux data are used in a formula based on Direct Simulation Monte Carlo (DSMC) simulations to determine the coefficients. The assembly also features a complementary capability for measuring the variation in gas density between the plates using electron-beam fluorescence. Surface materials examined include 304 stainless steel, gold, aluminum, platinum, silicon, silicon nitride, and polysilicon. Effects of gas composition, surface roughness, and surface contamination have been investigated with this system; the behavior of gas mixtures has also been explored. Without special cleaning procedures, thermal accommodation coefficients for most materials and surface finishes were determined to be near 0.95, 0.85, and 0.45 for argon, nitrogen, and helium, respectively. Surface cleaning by in situ argon-plasma treatment reduced coefficient values by up to 0.10 for helium and by ~0.05 for nitrogen and argon. Results for both single-species and gas-mixture experiments compare favorably to DSMC simulations.

Trott, Wayne M.; Castañeda, Jaime N.; Torczynski, John R.; Gallis, Michael A.; Rader, Daniel J.

2011-03-01

67

Highly Precise Catheter Driving Mechanism for Intravascular Neurosurgery  

Microsoft Academic Search

Recently, MIS (minimum invasive surgery) has attracted most of doctors and patient. It has been widely used in many kinds of surgeries, especially in intravascular neurosurgery. But there are several problems in intravascular neurosurgery: doctor's exposure to X-ray, few well skilled doctors, high risk of the catheter insertion. To solve these problems, we developed a highly precise remote control system

Weixing Feng; Changmin Chi; Huanran Wang; Kejun Wang; Xiufen ye; Shuxiang Guo

2006-01-01

68

Testing a collision avoidance display with high-precision navigation  

NASA Astrophysics Data System (ADS)

Recent years have seen a rise in sophisticated navigational positioning techniques. Starting from classical GPS, differential GPS, ground-based augmentation, and raw data submission have opened possibilities for high precision lateral positioning for beyond what was thinkable before. This yields new perspectives for technologies like ACAS/TCAS, by enabling last-minute lateral avoidance as a supplement to the established vertical avoidance maneuvers. Working together with Ohio University's Avionics Department, DLR has developed and tested a set of displays for situational awareness and lateral last-minute avoidance in a collision situation, implementing some state-of-the art ideas in collision avoidance. The displays include the possibility to foresee the hazard zone of a possible intruder and thus avoid that zone early. The displays were integrated into Ohio University's experimental airplane, and a flight experiment was conducted to make a first evaluation of the applicability. The tests were carried out in fall 2012. We will present the principal architecture of the displays and detail the implementation into the flight carrier. Furthermore, we will give first results of the displays' performance.

Peinecke, Niklas; Uijt de Haag, Maarten; Meysel, Frederik; Duan, Pengfei; Küppers, Rene; Beernink, Bram

2013-06-01

69

New technique of machining high precision mirror surface press roller  

NASA Astrophysics Data System (ADS)

High precision mirror surface press roller machining technique of corrosion and grinding proof is one of the key techniques that the production enterprises as well as the machining and manufacturing of the following industries sought to resolve for a long time: plastics, papermaking, rubber, film, and chip production. In Oct. 1984, a new comprehensive machining technique of metal brush coating, grinding with abrasive belt, as well as buffing was used to conduct nearly 20 experiments. In Jan. 1985, a pair of middle convex high precision mirror surface press rollers was successfully machined. The technical process is described.

Hongsen, Deng

1991-03-01

70

The experimental study of a precision parallel manipulator with binary actuation: With application to MRI cancer treatment  

Microsoft Academic Search

In this paper the performance of a high-precision parallel robot manipulator with bistable actuation is experimentally evaluated. The manipulator is for performing prostate cancer biopsy and treatment within the bore of a magnetic resonance imaging (MRI) system. The analysis and simulations have shown that this bistable manipulator is able to perform well with dielectric elastomer actuators that have been shown

Kenjiro Tadakuma; Lauren M. Devita; Jean-sebastien Plante; Yan Shaoze; Steven Dubowsky

2008-01-01

71

High-precision measurement of absolute temperatures using thermistors  

Microsoft Academic Search

High-precision temperature measuring technique presupposes a high standard of quality of all components of the measuring system. Most important is the temperature sensor. Thermistors have been proved good for long-term stability in a limited temperature range from - 20 to + 50 °C. The non-linear characteristic of the thermistor can be mathematically described. Multislope analogue-digital converters with very high resolution

Volker H. Hans

72

Magnetic levitated high precision positioning system based on antagonistic mechanism  

Microsoft Academic Search

A six degree-of-freedom magnetically levitated high precision micro positioning system is designed to get rid of the friction which is one of the important factors limiting the resolution and accuracy of positioning devices. Since magnetic levitation systems are inherently unstable, most of the emphasis is placed on a magnetic circuit design so as to increase the system dynamic stability. For

Kee-Bong Choi; Soo-Hyun Kim; Yoon Keun Kwak

1996-01-01

73

A High-Precision NDIR Gas Sensor for Automotive Applications  

Microsoft Academic Search

A new high-precision spectroscopic gas sensor measuring carbon dioxide (CO2) for harsh environmental conditions of automotive applications is presented. The carbon dioxide concentration is the primary parameter for sensing in cabin air quality, as well as an important safety parameter when R744 (carbon dioxide) is used as the refrigerant in the air conditioning system. The automotive environment challenges the potential

Robert Frodl; Thomas Tille

2006-01-01

74

ALGORITHMS AND EVALUATION OF A HIGH PRECISION TOOL MEASUREMENT SYSTEM  

Microsoft Academic Search

A methodology for proving the accuracy of a system for high precision measurement of cutting tools is described. The tools are backlit by infrared illumination. Images are acquired by telecentric lenses and standard cameras and framegrabbers. The outer boundary of the tools is extracted by subpixel edge detection and is then approximated by lines and circular arcs. All processing is

Gerhard Blahusch; Wolfgang Eckstein; Carsten Steger; Stefan Lanser

75

High Precision Differential Photometry with CCDs: A Brief History  

Microsoft Academic Search

I present a brief history of the hunt for high photometric precision using CCDs in astronomy. CCDs were invented in 1969 and only 7 years later they started to appear at the major observatories of the time. The next 10 years constituted a steep learning curve for astronomers as they developed an understanding of CCDs as instruments and analysis techniques

Steve B. Howell

2011-01-01

76

Electric Quadrupole Transition Measurements of Hydrogen Molecule with High Precision  

NASA Astrophysics Data System (ADS)

Molecular hydrogen is the most fundamental, and the only neutral molecule expected to be both calculated and measured with extremely high accuracy. High-precision measurements of its spectroscopy, especially the levels at the electric ground state, play an important role in the examination of precise quantum chemistry calculations and some fundamental physical constants. In the infrared region, H_2, being a homonuclear diatomic molecule, only has very weak electric quadrupole transitions. We established a new spectroscopy approach with ultra-high precision and sensitivity as well, based on a laser-locked cavity ring-down spectrometer. An equivalent absorption path-length of thousands of kilometers and a frequency precision of 10^{-5} cm^{-1} have been achieved. Ro-vibrational spectra of the second overtone of H_2 have been recorded. The obtained results will provide a direct examination of the high-accuracy quantum theory. It also shades light on the determination of fundamental physical constants such as the electron/proton mass ratio in a molecular system.

Cheng, Cun-Feng; Wang, Jin; Tan, Yan; Liu, An-Wen; Hu, Shui-Ming

2013-06-01

77

Fault-tolerant defect prediction in high-precision foundry  

Microsoft Academic Search

High-precision foundry production is subjected to rigorous quality controls in order to ensure a proper result. Such exams, however, are extremely expensive and only achieve good results in a posteriori fashion. In previous works, we presented a defect prediction system that achieved a 99% success rate. Still, this approach did not take into account sufficiently the geometry of the casting

Mikel Salazar; David Gallego; Yoseba K. Penya; Igor Santos; Pablo G. Bringas

2010-01-01

78

Advanced fault prediction in high-precision foundry production  

Microsoft Academic Search

Microshrinkages are known as probably the most difficult defects to avoid in high-precision foundry due to the large number of factors involved in their apparition. The presence of this failure renders the casting invalid, with the subsequent cost increment. Bayesian networks allow to model the foundry process as a probabilistic constellation of interrelated variables. In this way, after a suitable

Yoseba K. Penya; Pablo G. Bringas; Argoitz Zabala

2008-01-01

79

8.4 High Precision Power Converters for Particle Accelerators  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume C 'Accelerators and Colliders' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the the Section '8.4 High Precision Power Converters for Particle Accelerators' of the Chapter '8 Accelerator Technology' with the content:

Bordry, F.; Burnet, J. P.; Bastos, M. Cerqueira

80

VIEW OF MICROMACHINING, HIGH PRECISION EQUIPMENT USED TO CUSTOM MAKE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF MICRO-MACHINING, HIGH PRECISION EQUIPMENT USED TO CUSTOM MAKE SMALL PARTS. LUMPS OF CLAY; SHOWN IN THE PHOTOGRAPH, WERE USED TO STABILIZE PARTS BEING MACHINED. (11/1/87) - Rocky Flats Plant, Stainless Steel & Non-Nuclear Components Manufacturing, Southeast corner of intersection of Cottonwood & Third Avenues, Golden, Jefferson County, CO

81

High precision levelling supporting the International Comparison of Absolute Gravimeters  

Microsoft Academic Search

High precision levelling is an indispensable method used to monitor benchmark and terrain stability at the Bureau International des Poids et Mesures (BIPM). Associated with the International Comparison of Absolute Gravimeters (ICAG), levelling measurements were carried out repeatedly over the past decades. A local gravity field strongly depends on vertical terrain deformation. 1 cm displacement implies about 2 µGal change

Z Jiang; M Becker; P Jousset; A Coulomb; L Tisserand; P Boulanger; D Lequin; F Lhermitte; J L Houillon; F Dupont

2012-01-01

82

High precision English base noun phrase identification based on \\  

Microsoft Academic Search

Based on classical model that used by software exploitation in the subject of Software Engineering - waterfall model, a high precision model for English noun phrase identification is presented. In this model, three important features (interior structure, context information and boundary character) in base noun phrase identification are orderly used, and the relative method (the rule method, the transfer-based and

Ying-Hong Liang; Tie-Jun Zhao; Hao Yu; Jian-Min Yao

2005-01-01

83

Fabrication and metrology of high-precision freeform surfaces  

NASA Astrophysics Data System (ADS)

Freeform applications are growing and include helmet-mounted displays, conformal optics (e.g. windows integrated into airplane wings), and those requiring the extreme precision of EUV. These non-rotationally symmetric surfaces pose challenges to optical fabrication, mostly in the areas of polishing and metrology. The varying curvature of freeform surfaces drives the need for smaller, more "conformal", tools for polishing and reference beams for interferometry. In this paper, we present fabrication results of a high-precision freeform surface. We will discuss the total manufacturing process, including generation, pre-polishing, MRF®, and metrology, highlighting the capabilities available in today's optical fabrication companies.

Supranowitz, Chris; Dumas, Paul; Nitzsche, Tobias; DeGroote Nelson, Jessica; Light, Brandon; Medicus, Kate; Smith, Nathan

2013-09-01

84

High Precision Differential Photometry with CCDs: A Brief History  

NASA Astrophysics Data System (ADS)

I present a brief history of the hunt for high photometric precision using CCDs in astronomy. CCDs were invented in 1969 and only 7 years later they started to appear at the major observatories of the time. The next 10 years constituted a steep learning curve for astronomers as they developed an understanding of CCDs as instruments and analysis techniques for use with digital images. In 1985, differential photometry with CCDs began producing light curves with precisions near 0.01 magnitude. By 2008, ground-based telescopes armed with CCDs and using differential techniques consistently can provide photometric precisions of 1 millimagnitude or better. The challenge now is to continue to improve the photometry using new types of CCD detectors and other advanced digital imagers.

Howell, Steve B.

85

High Precision U/Th Dating of First Polynesian Settlement  

PubMed Central

Previous studies document Nukuleka in the Kingdom of Tonga as a founder colony for first settlement of Polynesia by Lapita peoples. A limited number of radiocarbon dates are one line of evidence supporting this claim, but they cannot precisely establish when this event occurred, nor can they afford a detailed chronology for sequent occupation. High precision U/Th dates of Acropora coral files (abraders) from Nukuleka give unprecedented resolution, identifying the founder event by 2838±8 BP and documenting site development over the ensuing 250 years. The potential for dating error due to post depositional diagenetic alteration of ancient corals at Nukuleka also is addressed through sample preparation protocols and paired dates on spatially separated samples for individual specimens. Acropora coral files are widely distributed in Lapita sites across Oceania. U/Th dating of these artifacts provides unparalleled opportunities for greater precision and insight into the speed and timing of this final chapter in human settlement of the globe.

Burley, David; Weisler, Marshall I.; Zhao, Jian-xin

2012-01-01

86

High Precision Spectroscopy of CH_5^+ Using Nice-Ohvms  

NASA Astrophysics Data System (ADS)

The elusive methonium ion, CH_5^+, is of great interest due to its highly fluxional nature. The only published high-resolution infrared spectrum remains completely unassigned to this date. The primary challenge in understanding the CH_5^+ spectrum is that traditional spectroscopic approaches rely on a molecule having only small (or even large) amplitude motions about a well-defined reference geometry, and this is not the case with CH_5^+. We are in the process of re-scanning Oka's spectrum, in the original Black Widow discharge cell, using the new technique of Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy (NICE-OHVMS). The high precision afforded by optical saturation in conjunction with a frequency comb allows transition line centers to be determined with sub-MHz accuracy and precision -- a substantial improvement over the 90 MHz precision of Oka's work. With a high-precision linelist in hand, we plan to search for four line combination differences to directly determine the spacings between rotational energy levels. Such a search is currently infeasible due to the large number of false positives resulting from the relatively low precision and high spectral density of Oka's spectrum. The resulting combination differences, in conjunction with state-of-the-art theoretical calculations from Tucker Carrington, may provide the first insight into the rotational structure of this unique molecular system. E. T. White, J. Tang, T. Oka, Science (1999) 284, 135--137. B. M. Siller, et al. Opt. Express (2011), 19, 24822--24827. K. N. Crabtree, et al. Chem. Phys. Lett. (2012), 551, 1--6. X. Wang, T. Carrington, J. Chem. Phys., (2008), 129, 234102.

Hodges, James N.; Perry, Adam J.; McCall, Benjamin J.

2013-06-01

87

Method of high precision interval measurement in pulse laser ranging system  

NASA Astrophysics Data System (ADS)

Laser ranging is suitable for laser system, for it has the advantage of high measuring precision, fast measuring speed,no cooperative targets and strong resistance to electromagnetic interference,the measuremen of laser ranging is the key paremeters affecting the performance of the whole system.The precision of the pulsed laser ranging system was decided by the precision of the time interval measurement, the principle structure of laser ranging system was introduced, and a method of high precision time interval measurement in pulse laser ranging system was established in this paper.Based on the analysis of the factors which affected the precision of range measure,the pulse rising edges discriminator was adopted to produce timing mark for the start-stop time discrimination,and the TDC-GP2 high precision interval measurement system based on TMS320F2812 DSP was designed to improve the measurement precision.Experimental results indicate that the time interval measurement method in this paper can obtain higher range accuracy. Compared with the traditional time interval measurement system,the method simplifies the system design and reduce the influence of bad weather conditions,furthermore,it satisfies the requirements of low costs and miniaturization.

Wang, Zhen; Lv, Xin-yuan; Mao, Jin-jin; Liu, Wei; Yang, Dong

2013-09-01

88

High precision calibration for 2D optical standard  

NASA Astrophysics Data System (ADS)

Photomask is a kind of 2-D optical standard with etched orthogonal coordinates made of a glass substrate chrominged or filmed with other metal. In order to solve the problems of measurement and traceability of ultra precision photomasks used in advanced manufacturing industry, 2-D photomask optical standard was calibrated in high precision laser two coordinate standard device. A high precision differential laser interferometer system was used for a length standard, a high magnification optical micro vision system was used for precision optical positioning feedback. In this paper, a image measurement model was purposed; A sampling window auto identification algorithm was designed. Grid stripe image could be identified and aimed at automatically by this algorithm. An edge detection method based on bidirection progressive scanning and 3-sigma rule for eliminating outliers in sampling window was found. Dirty point could be removed with effect. Edge detection error could be lowered. By this means, the measurement uncertainty of 2-D optical standard's ruling span was less than 0.3 micrometer (k=2).

Sun, Shuanghua; Gan, Xiaochuan; Xue, Zi; Ye, Xiaoyou; Wang, Heyan; Gao, Hongtang

2012-10-01

89

Proposed precision laser spectrometer for trapped, highly charged ions  

SciTech Connect

We propose a type of precision laser spectrometer for trapped, highly charged ions nearly at rest. It consists of a cylindrical, open-endcap Penning trap in which an externally produced bunch of highly charged ions can be confined and investigated by means of laser spectroscopy. The combination of confinement, cooling, and compression of a dense ion cloud will allow the ground-state hyperfine splitting in highly charged ions to be measured with an accuracy three orders of magnitude better than in any previous experiment. A systematic study of different charge states and different isotopes of the same element allows for highly sensitive tests of bound-state quantum electrodynamics and for a precision determination of nuclear properties. Apart from stable isotopes, radioactive species with half-lives longer than about 1 hour also can be investigated.

Vogel, M.; Winters, D.F.A.; Segal, D.M.; Thompson, R.C. [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom)

2005-10-15

90

High-speed Precise Laser Cutting with Copper Bromide Laser  

Microsoft Academic Search

The application of the copper bromide (CuBr) laser as an attractive tool in the cutting of different materials has been demonstrated. High-quality precision cutting was established on several materials with a negligible heat- affected zone (HAZ). That good performance was a result of the combination of high power visible radiation, short pulses, and close to the diffraction-limited laser beam divergence

I. I. Balchev; N. I. Minkovski; I. K. Kostadinov; N. V. Sabotinov

91

A high precision CMOS weak current readout circuit  

NASA Astrophysics Data System (ADS)

This paper presents a high precision CMOS weak current readout circuit. This circuit is capable of converting a weak current into a frequency signal for amperometric measurements with high precision and further delivering a 10-bit digital output. A fast stabilization-enhanced potentiostat has been proposed in the design, which is used to maintain a constant bias potential for amperometric biochemical sensors. A technique based on source voltage shifting that reduces the leakage current of the MOS transistor to the reverse diode leakage level at room temperature was employed in the circuit. The chip was fabricated in the 0.35 ?m chartered CMOS process, with a single 3.3 V power supply. The interface circuit maintains a dynamic range of more than 100 dB. Currents from 1 pA to 300 nA can be detected with a maximum nonlinearity of 0.3% over the full scale.

Qisong, Wu; Haigang, Yang; Tao, Yin; Chong, Zhang

2009-07-01

92

Slow Control System for the NIFFTE High Precision TPC  

NASA Astrophysics Data System (ADS)

The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) has designed a Time Projection Chamber (TPC) to measure neutron induced fission cross-section measurements of the major actinides to sub-1% precision over a wide incident neutron energy range. These measurements are necessary to design the next generation of nuclear power plants. In order to achieve our high precision goals, an accurate and efficient slow control system must be implemented. Custom software has been created to control the hardware through Maximum Integration Data Acquisition System (MIDAS). This includes reading room and device temperature, setting the high voltage power supplies, and reading voltages. From hardware to software, an efficient design has been implemented and tested. This poster will present the setup and data from this slow control system.

Thornton, Remington

2010-11-01

93

Fourier domain optical coherence tomography for high-precision profilometry  

NASA Astrophysics Data System (ADS)

A Fourier domain (FD) optical coherence tomography (OCT) system is shown to be capable of profilometry with two orders of magnitude better accuracy than the axial imaging resolution of the system. High precision OCT profilometry not only achieves similar accuracy as commercial white light interferometry based profilometers but is also capable of profilometry on complex subsurface structures with multiple interfaces of low reflectance. An accuracy of 55nm was achieved with a ThorLabs SROCT on a lab bench without special anti-vibration devices. This technique has the potential for a range of applications, such as high precision refractive index measurements and simultaneous dynamic monitoring of the interface structure of a drying varnish and the substrate.

Lawman, Samuel; Liang, Haida

2009-07-01

94

An integral process model for high precision composite forming  

Microsoft Academic Search

High precision composite forming implies control of the fibre orientation, residual stresses and wrinkling in the product to be manufactured. Finite Element based process simulations can assist in achieving this right-first-time manufacturing. A first order approximation of the full manufacturing process is presented in a three-step approach: a multilayer Finite Element drape simulation, a micromechanics based stiffness and stress prediction

Remko Akkerman; Edwin A. D. Lamers; Sebastiann Wijskamp

2006-01-01

95

High-precision magnetic levitation stage for photolithography  

Microsoft Academic Search

In this paper, we present a high-precision magnetic levitation (maglev) stage for photolithography in semiconductor manufacturing. This stage is the world’s first maglev stage that provides fine six-degree-of-freedom motion controls and realizes large (50 mm × 50 mm) planar motions with only a single magnetically levitated moving part. The key element of this stage is a linear motor capable of

Won-jong Kim; David L. Trumper

1998-01-01

96

A new approach to high precision 3-D measuring system  

Microsoft Academic Search

A 3-D measuring system is important in many industrial applications like object modeling, medical diagnosis, CAD\\/CAM, multi-media, and virtual reality systems. However, it takes a lot of effort and cost to develop a high precision 3-D measuring system. A novel approach is introduced in this paper, with a view to develop a 3-D measuring system to meet the requirements of

Chi-fang Lin; Chih-yang Lin

1999-01-01

97

A Concept for High Precision Astrometry with a Space Coronagraph  

Microsoft Academic Search

High precision (micro-arcsecond) astrometry of nearby bright stars is theoretically (in the photon noise limit) possible with a space coronagraph with the addition of a wide field diffraction limited camera imaging an annulus of background stars around the central coronagraphic field. With micro arcsecond accuracy on a 1.4-m telescope, the mass of all planets that can be imaged by the

Olivier Guyon; M. Shao

2010-01-01

98

High Precision Differential Photometry with CCDs: A Brief History  

Microsoft Academic Search

\\u000a I present a brief history of the hunt for high photometric precision using CCDs in astronomy. CCDs were invented in 1969 and\\u000a only 7?years later they started to appear at the major observatories of the time. The next 10?years constituted a steep learning\\u000a curve for astronomers as they developed an understanding of CCDs as instruments and analysis techniques for use

Steve B. Howell

99

High-Precision Direct Method for the Radiative Transfer Problems  

NASA Astrophysics Data System (ADS)

It is the main aim of this paper to investigate the numerical methods of the radiative transfer equation. Using the five-point formula to approximate the differential part and the Simpson formula to substitute for integral part respectively, a new high-precision numerical scheme, which has 4-order local truncation error, is obtained. Subsequently, a numerical example for radiative transfer equation is carried out, and the calculation results show that the new numerical scheme is more accurate.

Zhang, Yan; Hou, Su-Qing; Yang, Ping; Wu, Kai-Su

2013-06-01

100

Multifunctional structure solutions for Ultra High Precision (UHP) machine tools  

Microsoft Academic Search

This paper aims to study innovative structure solutions for Ultra High Precision (UHP) Machine Tools (MT) within machining applications at micro\\/mesoscale level (10–10000?m range). There are many aspects that can affect the accuracy of UHP machining performance. The most important issues are related to the static, dynamic and thermal behaviour of the machines. This paper shows a complete study and

F. Aggogeri; A. Merlo; M. Mazzola

2010-01-01

101

The high-quality precision casting of titanium alloys  

Microsoft Academic Search

A technique for the high-quality precision casting of titanium alloys has been developed that consists of the instantaneous\\u000a dissociation of oxide at the metal-mold interface, followed by the rapid absorption and diffusion of the dissociated oxygen\\u000a into the subsurface of the cast parts during solidification and cooling. In centrifugal casting trials using less molten alloy\\u000a than required to completely fill

Ken-Ichiro Suzuki

1998-01-01

102

A high-precision weak current source using operational amplifiers  

Microsoft Academic Search

A high-accuracy current source has been developed for the generation of very small currents (below 10?pA) based on operational amplifiers. Precision current sources have been built using op amps, resistors, constant voltage and standard resistance values to gain weak current output with V–I converter. A complete analysis of this current source with respect to its dynamic properties, its equivalent relative

Shengjie Lei; Zhiyong Wei

2012-01-01

103

High precision electrostatic potential calculations for cylindrically symmetric lenses  

SciTech Connect

A method is developed for a potential calculation within cylindrically symmetric electrostatic lenses using mesh relaxation techniques, and it is capable of considerably higher accuracies than currently available. The method involves (i) creating very high order algorithms (orders of 6, 8, and 10) for determining the potentials at points in the net using surrounding point values, (ii) eliminating the effect of the large errors caused by singular points, and (iii) reducing gradients in the high gradient regions of the geometry, thereby allowing the algorithms used in these regions to achieve greater precisions--(ii) and (iii) achieved by the use of telescopic multiregions. In addition, an algorithm for points one unit from a metal surface is developed, allowing general mesh point algorithms to be used in these situations, thereby taking advantage of the enhanced precision of the latter. A maximum error function dependent on a sixth order gradient of the potential is defined. With this the single point algorithmic errors are able to be viewed over the entire net. Finally, it is demonstrated that by utilizing the above concepts and procedures, the potential of a point in a reasonably high gradient region of a test geometry can realize a precision of less than 10{sup -10}.

Edwards, David Jr. [238 Marylyn Lane, Newark, Vermont 05871 (United States)

2007-02-15

104

Modular Gravitational Reference Sensor for High Precision Astronomical Space Missions  

NASA Astrophysics Data System (ADS)

We review the progress in developing the Modular Gravitational Reference Sensor (modular GRS) [1], which was first proposed as a simplified core sensor for space gravitational wave detection missions. In a modular GRS, laser beam from the remote the sensor does not illuminate the proof mass directly. The internal measurement from housing to proof mass is separated from the external interferometry. A double side grating may further simplify the structure and may better preserve the measurement precision. We review the recent progress in developing modular GRS at Stanford. We have further studied optical sensing design that combines advantage of high precision interferometric measurement and robust optical shadow sensing scheme. We have made critical progress in optical measurement of the center of mass position of a spherical proof mass at a precision without costing the dynamic range while spinning. We have successfully demonstrated the feasibility of fabricating localized grating pattern onto the dielectric and gold materials. We have conducted an initial experiment of rf heterodyne of cavity reflection and thus lowered optical power than that in the direct detection. We have further studied UV LED that will be used for AC charge management experiment. The modular GRS will be an in-time, cost effective product for the advanced Laser Interferometric Space Antenna (LISA) and the Big Bang Observatory (BBO). [1] K. Sun, G. Allen, S. Buchman, D. DeBra, and R. L. Byer, “Advanced Architecture for High Precision Space Laser Interferometers”, 5th International LISA Symposium, ESTEC, Noordwijk, The Netherlands, 12-16 July 2004. Class. Quantum Grav. 22 (2005) S287-S296.

Sun, Ke-Xun; Allen, G.; Buchman, S.; Byer, R. L.; Conklin, J. W.; DeBra, D. B.; Gill, D.; Goh, A.; Higuchi, S.; Lu, P.; Robertson, N.; Swank, A.

2006-12-01

105

Analytic results for high-precision and cryogenic lens holders  

NASA Astrophysics Data System (ADS)

For the Euclid mission a pre-development phase is implemented to prove feasibility of individual components of the system. The optical system of EUCLID Near-Infrared Spectrometer & Photometer (NISP) is composed of 4 lenses, bandpass filters and grisms. The lenses are made of different materials: the corrector lens (fused silica) directly behind the dichroic and the lenses L1 (CaF2), L2 (LF5G15), and L3 (LF5G15) that are mounted in a separate lens barrel design. Each lens has its separate mechanical interface to the lens barrel, the so called adaption ring. The adaption ring shall provide the necessary elasticity caused by different CTEs of the lens and ring materials, as well as shall allow the high position accuracy of the lenses relative to the lens barrel and the optical axis. The design drivers for the adaption ring are high precision, cryogenic operation temperature (150 K) and the large dimension of the lenses (150 - 170 mm). The design concept of the adaption ring is based on solid state springs, which shall both provide sufficient protection against vibration loads at ambient temperature as well as high precision (< +/-10 ?m) and stability at cryogenic temperatures. Criteria for the solid state spring design shall be low radial forces at cryogenic conditions to avoid any refractive index and polarization variations. The design shall be compliant to the large temperature differences between assembly and operation, the high precision and non-deformation requirements of the lenses as well as to the deviating CTEs of the selected lens materials. The paper describes the selected development approach including justification, thermal and structural analysis.

Boesz, A.; Grupp, F.; Mottaghibonab, A.; Zeh, T.; Geis, N.; Bender, R.

2011-09-01

106

High-precision ground-based photometry of exoplanets  

NASA Astrophysics Data System (ADS)

High-precision photometry of transiting exoplanet systems has contributed significantly to our understanding of the properties of their atmospheres. The best targets are the bright exoplanet systems, for which the high number of photons allow very high signal-to-noise ratios. Most of the current instruments are not optimised for these high-precision measurements, either they have a large read-out overhead to reduce the readnoise and/or their field-of-view is limited, preventing simultaneous observations of both the target and a reference star. Recently we have proposed a new wide-field imager for the Observatoir de Mont-Megantic optimised for these bright systems (PI: Jayawardhana). The instruments has a dual beam design and a field-of-view of 17' by 17'. The cameras have a read-out time of 2 seconds, significantly reducing read-out overheads. Over the past years we have obtained significant experience with how to reach the high precision required for the characterisation of exoplanet atmospheres. Based on our experience we provide the following advice: Get the best calibrations possible. In the case of bad weather, characterise the instrument (e.g. non-linearity, dome flats, bias level), this is vital for better understanding of the science data. Observe the target for as long as possible, the out-of-transit baseline is as important as the transit/eclipse itself. A short baseline can lead to improperly corrected systematic and mis-estimation of the red-noise. Keep everything (e.g. position on detector, exposure time) as stable as possible. Take care that the defocus is not too strong. For a large defocus, the contribution of the total flux from the sky-background in the aperture could well exceed that of the target, resulting in very strict requirements on the precision at which the background is measured.

de Mooij, Ernst J. W.; Jayawardhana, Ray

2013-04-01

107

Describing oscillations of high energy neutrinos in matter precisely.  

PubMed

We present a formalism for precise description of oscillation phenomena in matter at high energies or high densities, V > Delta m(2)/2E, where V is the matter-induced potential of neutrinos. The accuracy of the approximation is determined by the quantity, where is the mixing angle in matter and is a typical change of the potential over the oscillation length (). We derive simple and physically transparent formulas for the oscillation probabilities, which are valid for arbitrary matter density profiles. They can be applied to oscillations of high-energy accelerator, atmospheric, and cosmic neutrinos in the matter of the Earth, substantially simplifying numerical calculations and providing an insight into the physics of neutrino oscillations in matter. The effect of parametric enhancement of the oscillations of high-energy neutrinos is considered. PMID:16384132

Akhmedov, E K H; Maltoni, M; Smirnov, A Y U

2005-11-15

108

Test results of high-precision large cryogenic lens holders  

NASA Astrophysics Data System (ADS)

For the Euclid mission a Pre-Development phase is implemented to prove feasibility of individual components of the system [1]. The Near Infrared Spectrometer and Photometer (NISP) of EUCLID requires high precision large lens holders (?170 mm) at cryogenic temperatures (150K). The four lenses of the optical system are made of different materials: fused silica, CaF2, and LF5G15 that are mounted in a separate lens barrel design. Each lens has its separate mechanical interface to the lens barrel, the so called adaption ring. The performance of the lens holder design is verified by adapted test equipment and test facility including an optical metrology system. The characterization of the lens deformation and displacement (decenter, tilt) due to mechanical loads of the holder itself as well as thermally induced loads are driven by the required submicron precision range and the operational thermal condition. The surface deformation of the lens and its holder is verified by interferometric measurements, while tilt and position accuracy are measured by in-situ fibre based distance sensors. The selected distance measurement sensors have the capability to measure in a few mm range with submicron resolution in ultra high vacuum, in vibration environments and at liquid nitrogen temperatures and below. The calibration of the measurement system is of crucial importance: impacts such as temperature fluctuation, surface roughness, surface reflectivity, straylight effects, etc. on the measured distance are carefully calibrated. Inbuilt thermal expansion effects of the fibre sensors are characterized and proven with lens dummy with quasi zero CTE. The paper presents the test results and measured performance of the high precision large cryogenic lens holders attained by the metrology system. These results are presented on behalf of the EUCLID consortium.

Gal, C.; Reutlinger, A.; Boesz, A.; Leberle, T.; Mottaghibonab, A.; Eckert, P.; Dubowy, M.; Gebler, H.; Grupp, F.; Geis, N.; Bode, A.; Katterloher, R.; Bender, R.

2012-09-01

109

High-Precision Timing of Several Millisecond Pulsars  

NASA Astrophysics Data System (ADS)

The highest precision pulsar timing is achieved by reproducing as accurately as possible the pulse profile as emitted by the pulsar, in high signal-to-noise observations. The best profile reconstruction can be accomplished with several-bit voltage sampling and coherent removal of the dispersion suffered by pulsar signals as they traverse the interstellar medium. The Arecibo Signal Processor (ASP) and its counterpart the Green Bank Astronomical Signal Processor (GASP) are flexible, state-of-the-art wide-bandwidth observing systems, built primarily for high-precision long-term timing of millisecond and binary pulsars. ASP and GASP are in use at the 300-m Arecibo telescope in Puerto Rico and the 100-m Green Bank Telescope in Green Bank, West Virginia, respectively, taking advantage of the enormous sensitivities of these telescopes. These instruments result in high-precision science through 4 and 8-bit sampling and perform coherent dedispersion on the incoming data stream in real or near-real time. This is done using a network of personal computers, over an observing bandwidth of 64 to 128 MHz, in each of two polarizations. We present preliminary results of timing and polarimetric observations with ASP/GASP for several pulsars, including the recently-discovered relativistic double-pulsar binary J0737-3039. These data are compared to simultaneous observations with other pulsar instruments, such as the new "spigot card" spectrometer on the GBT and the Princeton Mark IV instrument at Arecibo, the precursor timing system to ASP. We also briefly discuss several upcoming observations with ASP/GASP.

Ferdman, R. D.; Stairs, I. H.; Backer, D. C.; Ramachandran, R.; Demorest, P.; Nice, D. J.; Lyne, A. G.; Kramer, M.; Lorimer, D.; McLaughlin, M.; Manchester, D.; Camilo, F.; D'Amico, N.; Possenti, A.; Burgay, M.; Joshi, B. C.; Freire, P. C.

2004-12-01

110

High-precision branching ratio measurement for the superallowed {beta}{sup +} emitter {sup 62}Ga  

SciTech Connect

A high-precision branching ratio measurement for the superallowed {beta}{sup +} decay of {sup 62}Ga was performed at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility. The 8{pi} spectrometer, an array of 20 high-purity germanium detectors, was employed to detect the {gamma} rays emitted following Gamow-Teller and nonanalog Fermi {beta}{sup +} decays of {sup 62}Ga, and the SCEPTAR plastic scintillator array was used to detect the emitted {beta} particles. Thirty {gamma} rays were identified following {sup 62}Ga decay, establishing the superallowed branching ratio to be 99.858(8)%. Combined with the world-average half-life and a recent high-precision Q-value measurement for {sup 62}Ga, this branching ratio yields an ft value of 3074.3{+-}1.1 s, making {sup 62}Ga among the most precisely determined superallowed ft values. Comparison between the superallowed ft value determined in this work and the world-average corrected Ft value allows the large nuclear-structure-dependent correction for {sup 62}Ga decay to be experimentally determined from the CVC hypothesis to better than 7% of its own value, the most precise experimental determination for any superallowed emitter. These results provide a benchmark for the refinement of the theoretical description of isospin-symmetry breaking in A{>=}62 superallowed decays.

Finlay, P.; Svensson, C. E.; Bandyopadhyay, D.; Grinyer, G. F.; Hyland, B.; Leach, K. G.; Phillips, A. A.; Schumaker, M. A.; Wong, J. [Department of Physics, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Ball, G. C.; Chakrawarthy, R. S.; Hackman, G.; Kanungo, R.; Morton, A. C.; Pearson, C. J.; Savajols, H. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3 (Canada); Leslie, J. R.; Towner, I. S. [Department of Physics, Queen's University, Kingston, Ontario K7L 3N6 (Canada); Austin, R. A. E.; Chaffey, A. [Department of Astronomy and Physics, Saint Mary's University, Halifax, Nova Scotia B3H 3C3 (Canada)] (and others)

2008-08-15

111

High-precision branching ratio measurement for the superallowed ?+ emitter Ga62  

NASA Astrophysics Data System (ADS)

A high-precision branching ratio measurement for the superallowed ?+ decay of Ga62 was performed at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility. The 8? spectrometer, an array of 20 high-purity germanium detectors, was employed to detect the ? rays emitted following Gamow-Teller and nonanalog Fermi ?+ decays of Ga62, and the SCEPTAR plastic scintillator array was used to detect the emitted ? particles. Thirty ? rays were identified following Ga62 decay, establishing the superallowed branching ratio to be 99.858(8)%. Combined with the world-average half-life and a recent high-precision Q-value measurement for Ga62, this branching ratio yields an ft value of 3074.3±1.1 s, making Ga62 among the most precisely determined superallowed ft values. Comparison between the superallowed ft value determined in this work and the world-average corrected F tmacr value allows the large nuclear-structure-dependent correction for Ga62 decay to be experimentally determined from the CVC hypothesis to better than 7% of its own value, the most precise experimental determination for any superallowed emitter. These results provide a benchmark for the refinement of the theoretical description of isospin-symmetry breaking in A?62 superallowed decays.

Finlay, P.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Towner, I. S.; Austin, R. A. E.; Bandyopadhyay, D.; Chaffey, A.; Chakrawarthy, R. S.; Garrett, P. E.; Grinyer, G. F.; Hackman, G.; Hyland, B.; Kanungo, R.; Leach, K. G.; Mattoon, C. M.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Ressler, J. J.; Sarazin, F.; Savajols, H.; Schumaker, M. A.; Wong, J.

2008-08-01

112

Multiple-sensor integration for rapid and high-precision coordinate metrology  

Microsoft Academic Search

The development of a multiple-sensor coordinate measuring system (CMM) is introduced and its applications to automated part localization and rapid surface digitization are experimentally demonstrated. The developed multiple-sensor CMM is characterized by an integrated use of a high-precision CMM equipped with a motorized touch probe, and a 3D active vision system, advanced computational software, and the associated electronics. The 3D

Tzung-Sz Shen; Jianbing Huang; Chia-Hsiang Menq

2000-01-01

113

High Pressure Experimental Methods  

Microsoft Academic Search

This book is a worthy addition to the literature on high-pressure techniques. Unlike earlier books, it emphasizes diamond - anvil cells, which are useful in the range from 1 kbar to multi-megabar pressures, while not neglecting the older techniques (piston - cylinder etc) which give much lower maximum pressures but in much larger volumes. The author take a refreshing approach

D J Dunstan

1996-01-01

114

High Precision Astrometry with Adaptive Optics aided Imaging  

NASA Astrophysics Data System (ADS)

More than 450 exoplanets are known and this number increases nearly every day. Only a few constraints on their orbital parameters and physical characteristics can be determined, as most exoplanets are detected indirectly. Measuring the astrometric signal of a planet by measuring the wobble of the host star yields the full set of orbital parameters. With this information the true masses of the planet candidates can be determined, making it possible to establish the candidates as real planets, brown dwarfs (BD) or low mass stars. In the context of this thesis, an M-dwarf with a BD candidate companion, discovered by radial velocity measurements, was observed within a monitoring program to detect the astrometric signal. Ground based adaptive optics aided imaging with ESO/NACO was used to establish its true nature (BD vs. star) and to investigate the prospects of this technique for exoplanet detection. The astrometric corrections necessary to perform high precision astrometry are described and their contribution to the overall precision is investigated. Due to large uncertainties in the pixel-scale and the orientation of the detector, no detection of the astrometric orbit signal was possible. The image quality of ground-based telescopes is limited by the turbulence in Earth's atmosphere. The induced distortions of the light can be measured and corrected with the adaptive optics technique. However, the correction is only useful within a small angle around the guide star. The novel correction technique of multi conjugated adaptive optics uses several guide stars to correct a larger field of view. The VLT/MAD instrument was built to demonstrate this technique. Observations with MAD are analyzed in terms of astrometric precision in this work. Two sets of data are compared, which were obtained in different correction modes: pure ground layer correction and full multi conjugated correction.

Meyer, Eva

2010-05-01

115

Experimental study on the precise orbit determination of the BeiDou navigation satellite system.  

PubMed

The regional service of the Chinese BeiDou satellite navigation system is now in operation with a constellation including five Geostationary Earth Orbit satellites (GEO), five Inclined Geosynchronous Orbit (IGSO) satellites and four Medium Earth Orbit (MEO) satellites. Besides the standard positioning service with positioning accuracy of about 10 m, both precise relative positioning and precise point positioning are already demonstrated. As is well known, precise orbit and clock determination is essential in enhancing precise positioning services. To improve the satellite orbits of the BeiDou regional system, we concentrate on the impact of the tracking geometry and the involvement of MEOs, and on the effect of integer ambiguity resolution as well. About seven weeks of data collected at the BeiDou Experimental Test Service (BETS) network is employed in this experimental study. Several tracking scenarios are defined, various processing schemata are designed and carried out; and then, the estimates are compared and analyzed in detail. The results show that GEO orbits, especially the along-track component, can be significantly improved by extending the tracking network in China along longitude direction, whereas IGSOs gain more improvement if the tracking network extends in latitude. The involvement of MEOs and ambiguity-fixing also make the orbits better. PMID:23529116

He, Lina; Ge, Maorong; Wang, Jiexian; Wickert, Jens; Schuh, Harald

2013-03-01

116

Experimental Study on the Precise Orbit Determination of the BeiDou Navigation Satellite System  

PubMed Central

The regional service of the Chinese BeiDou satellite navigation system is now in operation with a constellation including five Geostationary Earth Orbit satellites (GEO), five Inclined Geosynchronous Orbit (IGSO) satellites and four Medium Earth Orbit (MEO) satellites. Besides the standard positioning service with positioning accuracy of about 10 m, both precise relative positioning and precise point positioning are already demonstrated. As is well known, precise orbit and clock determination is essential in enhancing precise positioning services. To improve the satellite orbits of the BeiDou regional system, we concentrate on the impact of the tracking geometry and the involvement of MEOs, and on the effect of integer ambiguity resolution as well. About seven weeks of data collected at the BeiDou Experimental Test Service (BETS) network is employed in this experimental study. Several tracking scenarios are defined, various processing schemata are designed and carried out; and then, the estimates are compared and analyzed in detail. The results show that GEO orbits, especially the along-track component, can be significantly improved by extending the tracking network in China along longitude direction, whereas IGSOs gain more improvement if the tracking network extends in latitude. The involvement of MEOs and ambiguity-fixing also make the orbits better.

He, Lina; Ge, Maorong; Wang, Jiexian; Wickert, Jens; Schuh, Harald

2013-01-01

117

High-precision time-interval measurement technique and methods  

NASA Astrophysics Data System (ADS)

This is a review of time-interval measurement methods and techniques. The paper begins with the definition of TDC or Time to Digit Converter. The interpolating principle, which modern TDC with high resolution and large dynamic range bases on, is introduced in the following. The mainstream time-interval measurement methods, including the direct counter method, TI stretching method, time-to-amplitude method, Vernier method, tapped delay line method and differential delay line method are described in detail. Detrimental factors, such as nonlinearity and metasability, which undermine the high precision, are also presented. To minimize these effects, the nonlinearity correction method, PLL and DLL technique are given. In addition, the future for time-interval measurement is proposed.

Zhang, Yan; Huang, Pei-Cheng

2006-03-01

118

REVIEW: Trap-assisted precision spectroscopy of highly charged ions  

NASA Astrophysics Data System (ADS)

Confinement of ions in traps is most often motivated by the extended times available for investigations and the possibility to cool the trapped ions' motions nearly to rest, thus avoiding various kinds of disturbances, including Doppler shifts and line broadening. However, specific properties of the confinement itself acting upon the trapped particles may also be used for studies of intrinsic ion properties. Here, we discuss a set of possibilities for high-precision spectroscopy of forbidden transitions in highly charged ions confined in a Penning trap. Such measurements make stringent tests of bound-state QED calculations possible and allow access to fundamental quantities such as the fine structure constant and nuclear properties of the ions.

Vogel, M.; Quint, W.

2009-08-01

119

High Precision Isotope Petrography by Secondary Ion Mass Spectrometry  

NASA Astrophysics Data System (ADS)

Since Shimizu et al. (GCA 1978) have demonstrated that in-situ micro-scale analyses of isotopes and trace elements in minerals were succeeded by secondary ion mass spectrometry (SIMS), geochemists develop the SIMS methods towards isotope mapping with spatial resolution of electron microscopy level. At present, high spatial resolution imaging by SIMS has been succeeded by scanning methods using ion-probe and by projection methods using stigmatic secondary ion optics. For high precision isotope analysis with high spatial resolution, intense secondary ions are indispensable for each pixel in the image. However, one of the major instrumental problems is that there were no adequate detectors for this purpose. In order to solve the problem, we proposed a two-dimensional solid-state ion detector called SCAPS (Takayanagi et al., IEEE Trans. 2003). The development is still continued and performances of recent SCAPS detector is achieved to: (1) direct sensitive for ions from single ion, (2) no dead time, and (3) perfect linearity of five orders of magnitude dynamic range. Installing the SCAPS detector into a stigmatic SIMS of Cameca ims-1270, we obtained oxygen isotope (delta-O-17 and delta-O-18) images of about 100 micrometer field with ~500 nm resolution and ~5 permil precision. The performance of high precision isotope imaging have might not be matured, but overcome a hurdle towards isotope petrography (Isotopography). We apply this isotopography to research fields of (a) survey of isotope anomalous micrograins and (b) isotope micro-distribution in rocks and minerals. In the application (a), we found in-situ presolar grains in meteorites (Nagashima et al., Nature 2004) and cosmic symplectite (COS) from a meteorite (Sakamoto et al., Science 2007). In the application (b), we showed how distribute oxygen isotopic compositions in micro-scale within CAI minerals (Yurimoto et al., Rev. Mineral. 2008; Fagan et al., in prep.). In combination fields of (a) and (b), we demonstrated how preserves Martian water and how contaminates terrestrial water in Martian meteorites (Greenwood et al., GRL 2008). These new knowledge from isotopography provides novel perspective of earth and planetary sciences.

Yurimoto, H.

2009-12-01

120

Precise measurements of the density and critical phenomena near the phase transitions in helium using high-Q niobium microwave cavities  

Microsoft Academic Search

The experimental approach of using high-Q niobium microwave resonator (Q?1010) and high resolution thermometry to achieve precise measurements of the density and critical phenomena in liquid helium near\\u000a phase transitions is described. The numerical verifications of the experimental feasibility as well as the applications of\\u000a the precision density measurement techniques are discussed.

N.-C. Yeh; W. Jiang; D. M. Strayer; N. N. Asplund

1996-01-01

121

Highly precise measurement of HIV DNA by droplet digital PCR.  

PubMed

Deoxyribonucleic acid (DNA) of the human immunodeficiency virus (HIV) provides the most sensitive measurement of residual infection in patients on effective combination antiretroviral therapy (cART). Droplet digital PCR (ddPCR) has recently been shown to provide highly accurate quantification of DNA copy number, but its application to quantification of HIV DNA, or other equally rare targets, has not been reported. This paper demonstrates and analyzes the application of ddPCR to measure the frequency of total HIV DNA (pol copies per million cells), and episomal 2-LTR (long terminal repeat) circles in cells isolated from infected patients. Analysis of over 300 clinical samples, including over 150 clinical samples assayed in triplicate by ddPCR and by real-time PCR (qPCR), demonstrates a significant increase in precision, with an average 5-fold decrease in the coefficient of variation of pol copy numbers and a >20-fold accuracy improvement for 2-LTR circles. Additional benefits of the ddPCR assay over qPCR include absolute quantification without reliance on an external standard and relative insensitivity to mismatches in primer and probe sequences. These features make digital PCR an attractive alternative for measurement of HIV DNA in clinical specimens. The improved sensitivity and precision of measurement of these rare events should facilitate measurements to characterize the latent HIV reservoir and interventions to eradicate it. PMID:23573183

Strain, Matthew C; Lada, Steven M; Luong, Tiffany; Rought, Steffney E; Gianella, Sara; Terry, Valeri H; Spina, Celsa A; Woelk, Christopher H; Richman, Douglas D

2013-04-03

122

High Precision Measurements of Neutron Beta-Decay at LANSCE  

NASA Astrophysics Data System (ADS)

High precision measurements of neutron beta-decay can be used to study the standard model of particle physics by testing the unitarity condition of the CKM matrix. Precise measurements of the neutrons' lifetime and one of its angular correlations are needed to determine the necessary standard model parameters for a unitarity test from neutron decay alone. Several experiments are underway at the Los Alamos Neutron Science Center (LANSCE) to measure these parameters using Ultra-Cold Neutrons (UCN). During the last 10 year a program to study neutron physics with UCN has been under development at LANSCE by an international team of scientists. The first experiment of this program, UCNA; which measures the decay correlation between the polarized neutron and the resulting beta particle, is currently running. A neutron lifetime experiment that monitors the decay rate of UCN trapped in a magnetic bottle with a gravitational top is being built and scheduled to run later this year. A second decay correlation experiment; (UCNB), which will measure the decay correlation between the polarized neutron and the resulting anti-neutrino is currently in the research and development phase. This talk will give an overview of these experiments, as well as other highlights from the UCN program at LANSCE.

Makela, Mark

2009-10-01

123

High Precision Light Element Isotopic Characterisation of Asteroidal Material  

NASA Astrophysics Data System (ADS)

The light elements, traditionally H, C, N, and O, are key elements in solar system processes, being the four most abundant reactive elements as well as forming the building blocks of life on Earth. Measurement of their isotopic composition in extraterrestrial materials has been a major component in our efforts to understand the origin and evolution of the solar nebula and the planetary bodies which it formed. In the rare, primitive chondritic meteorites all four of these elements reveal extreme variations in their isotopic composition, characteristic of specific nucleosynthetic processes, in small grains formed in circumstellar environments and which survived homogenization in the solar nebula. However, most material was relatively well homogenized in the solar nebula and any surviving isotopic extremes were further smoothed out during planetary processes such as melting and metamorphism such that typical evolved planetary materials display far more restricted isotopic variation. In the case of hydrogen the observed variations still remain relatively large due to the large mass difference in its two isotopes such that fractionation results in large isotopic shifts. Equally, the isotopic composition of nitrogen remains highly enigmatic with large variations from a range of meteorites and lunar materials. In contrast carbon, and especially oxygen, display very restricted isotopic variations, of the order of one and three percent respectively, in all meteorite types. One of the main compromises made for remote analyses during spaceflight experiments is that of analytical precision. This is particularly true for light element isotopic analyses--to obtain the necessary high precision magnetic sector mass spectrometers have to be used and to extract the species of interest requires heating the samples to high temperature followed by considerable processing of the gases evolved before analysis can commence. This requires mass and power budgets which have so far been entirely unrealistic, although there are on-going projects at the PSRI to improve the precision of instrumentation for remote stable isotope measurements. It is for these reasons that detailed analysis of carbon and oxygen of samples of asteroidal material require analyses to be performed in the laboratory with returned samples. Additional information is contained in the original extended abstract.

Franchi, I. A.; Baker, L.; Wright, I. P.; Pillinger, C. T.

2000-01-01

124

Towards ultra-precise optical interference filters on large area: computational and experimental optimization of the homogeneity of magnetron-sputtered precision optical coatings  

NASA Astrophysics Data System (ADS)

The optimization of the uniformity of high precision optical filters is often a critical and time consuming procedure. The goal of the present paper is to evaluate critical factors that influence the thickness distribution on substrates during a magnetron sputter process. A new developed sputter coater “EOSS” was used to deposit SiO2 and Nb2O5 single films and optical filters. It is based on dynamic deposition using a rotating turntable. Two sets of cylindrical double magnetrons are used for the low and the high index layers, respectively. In contrast to common planar magnetrons, the use of cylindrical magnetrons should yield a more stable distribution during the lifetime of the target. The thickness distribution on the substrates was measured by optical methods. Homogenization is carried out by shaping apertures. The distribution of the particle flow from the cylindrical magnetron was simulated using particle-in-cell Monte Carlo plasma simulation developed at Fraunhofer IST. Thickness profiles of the low index and the high index layers are calculated by numerical simulation and will be compared with the experimental data. Experimental factors such as wobbling of the magnetron during rotation, geometrical changes of critical components of the coater such as uniformity shapers as well as gas flow variations will be evaluated and discussed.

Vergöhl, Michael; Pflug, Andreas; Rademacher, Daniel

2012-09-01

125

A high-precision study of anharmonic-oscillator spectra  

SciTech Connect

High-precision methods are developed to evaluate eigenvalues for all states {vert_bar}{ital m,N}{r_angle} of the x{sup 2m} anharmonic oscillators with {ital m} from 2 to 6, for all values of the anharmonicity parameter. There are three basic steps: rescaling to introduce a length scale natural to the problem; use of fifth-order JWKB to generate an accurate starting estimate of the rescaled energy; and shifted (resolvent-based) Lanczos algorithm to sharpen the initial JWKB estimate. JWKB itself gives 33-figure accuracy for {ital N} greater than 1500 (for m=2) to 3500 (for m=6). With the JWKB starting energy, the shifted Lanczos algorithm converges to 33 figures in 3 iterations or less for all states. These methods are used in a study of the systematics of anharmonic-oscillator spectra and of the physical effects of the rescaling transformation. {copyright} 1999 Academic Press, Inc.

Macfarlane, M.H. [Department of Physics and Nuclear Theory Center, Indiana University, Bloomington, Indiana 47405 (United States)

1999-02-01

126

Thermal-mechanical behavior of high precision composite mirrors  

SciTech Connect

Composite mirror panels were designed, constructed, analyzed, and tested in the framework of a NASA precision segmented reflector task. The deformations of the reflector surface during the exposure to space enviroments were predicted using a finite element model. The composite mirror panels have graphite-epoxy or graphite-cyanate facesheets, separated by an aluminum or a composite honeycomb core. It is pointed out that in order to carry out detailed modeling of composite mirrors with high accuracy, it is necessary to have temperature dependent properties of the materials involved and the type and magnitude of manufacturing errors and material nonuniformities. The structural modeling and analysis efforts addressed the impact of key design and materials parameters on the performance of mirrors. 4 refs.

Kuo, C.P.; Lou, M.C.; Rapp, D.

1993-01-01

127

High precision Y89(?,?)Y89 scattering at low energies  

NASA Astrophysics Data System (ADS)

Elastic scattering cross sections of the Y89(?,?)Y89 reaction have been measured at energies Ec.m.=15.51 and 18.63 MeV. The high-precision data for the semimagic N=50 nucleus Y89 are used to derive a local potential and to evaluate the predictions of global and regional ?-nucleus potentials. The variation of the elastic ?-scattering cross sections along the N=50 isotonic chain is investigated by a study of the ratios of angular distributions for Y89(?,?)Y89 and Mo92(?,?)Mo92 at Ec.m.?15.51 and 18.63 MeV. This ratio is a very sensitive probe at energies close to the Coulomb barrier, where scattering data alone is usually not enough to characterize the different potentials. Furthermore, ?-cluster states in Nb93=Y89?? are investigated.

Kiss, G. G.; Mohr, P.; Fülöp, Zs.; Galaviz, D.; Gyürky, Gy.; Elekes, Z.; Somorjai, E.; Kretschmer, A.; Sonnabend, K.; Zilges, A.; Avrigeanu, M.

2009-10-01

128

High-precision digital charge-coupled device TV system  

NASA Astrophysics Data System (ADS)

In certain test, measurement, and research applications of CCD TV systems, the greater accuracy than usual 8-bit frame-grabbers can provide is demanded without the system being too expensive. The paper presents the concept and features of the high-precision low-cost digital CCD TV system intended for obtaining 12-bit monochrome images of immobile or relatively slow moving objects. The increase in accuracy is achieved by the specific digitization procedure -- one column per frame, which combines the benefits of a slow A/D converter with real-time TV imaging compatibility. To reduce speed restrictions on sample- and-hold circuits, a zoomed pixel read out cycle, corresponding to the pixel to be digitized, is proposed. The system provides great flexibility in choice of integration times and readout rates by means of a programmable readout sequencer, and is easily adaptable to various user demands and CCDs types.

Vishnevsky, Grigory I.; Ioffe, S. A.; Berezin, V. Y.; Rybakov, M. I.; Mikhaylov, A. V.; Belyaev, L. V.

1991-06-01

129

High-precision Mg isotopic systematics of bulk chondrites  

NASA Astrophysics Data System (ADS)

Variations of the mass-independent abundance of 26Mg ( ?26Mg*) and stable Mg ( ?25Mg) isotope composition of chondrites are important because they constrain the homogeneity of 26Al and Mg isotopes in the proto-planetary disc and the validity of the short-lived 26Al-to- 26Mg chronometer applied to meteorites. We present high-precision Mg isotope data and Al/Mg ratios of chondrites representing nearly all major chondrite classes, including a step-leaching experiment on the CM2 chondrite Murchison. ?26Mg* variations in leachates of Murchison representing acid soluble material are ? 30 times smaller than reported for neutron-rich isotopes of Ti and Cr and do not reveal resolvable deficits in ?26Mg* (-0.002 to + 0.118‰). Very small variations in ?26Mg* anomalies in bulk chondrites (-0.006 to + 0.019‰) correlate with increasing 27Al/ 24Mg ratios and ?50Ti, reflecting the variable presence of calcium-aluminium-rich inclusions (CAIs) in some types of carbonaceous chondrites. Similarly, release of radiogenic 26Mg produced by 26Al decay from CAI material in the step-leaching of Murchison best explains the high ?26Mg* observed in the last, aggressive, leaching steps of this experiment. Overall, the observed variations in ?26Mg* are small and potential differences beyond that which result from the presence of CAI-like material cannot be detected within the analytical uncertainties of this study (± 0.004‰). The results do not allow radical heterogeneity of 26Al (?±30%) or measurable Mg nucleosynthetic heterogeneity (?±0.005‰) to have existed on a planetesimal scale in the proto-planetary disc. Combined with published ?26Mg* data for CAIs, the bulk chondrite data yield a precise initial ( 26Al/ 27Al) 0 = (5.21 ± 0.06) × 10 -5 and ?26Mg* = -0.0340 ± 0.0016‰ for the Solar System. However, it is not possible with the currently available data to determine with certainty whether CAIs and the material from which planetesimals accreted including chondrite parent bodies had precisely the same initial levels of 26Al, although planetesimals and planets appear to have accreted from material with a mean initial ( 26Al/ 27Al) 0 in the range of 2.1 to 6.7 × 10 - 5 . The average stable Mg isotope composition of all analysed chondrites, with the exception of a chondrule from the CBa chondrite Gujba ( ?25Mg DSM-3 = -0.032 ± 0.035‰), is ?25Mg DSM-3 = -0.152 ± 0.079‰ (2 sd) and is indistinguishable from that of the Earth's mantle.

Schiller, Martin; Handler, Monica R.; Baker, Joel A.

2010-08-01

130

Precise lattice parameter comparison of highly perfect silicon crystals  

NASA Astrophysics Data System (ADS)

As a part of the International Avogadro Project we have utilized a state-of-the-art lattice comparator at the National Institute of Standards and Technology (NIST) to measure relative lattice parameter differences that are of the order of 10-8. Samples have been prepared from NRLM3, NRLM4, WASO04 and WASO17 material, which are of great importance in terms of a precise determination of the silicon d220 lattice parameter. The experimental set-up at NIST consists of a two-source, two-crystal Laue x-ray diffractometer. It uses a heterodyne interferometer to control the position of the first crystal with an uncertainty of 2 × 10-9 rad. From a least-squares fit we estimate the measurement uncertainty for a relative lattice parameter comparison at about 3 × 10-9. The measured lattice parameter variation across each individual sample indicates that the lattice uniformity of a particular specimen has to be carefully considered in view of comparing similar, though physically different, samples made out of the same material.

Hanke, M.; Kessler, E. G.

2005-05-01

131

Design of a new high precision computer numerical control  

SciTech Connect

The purpose of this project is to produce a generic high precision computer numerical controller (CNC) for use on microinch- and sub-microinch-resolution machine tools at the Lawrence Livermore National Laboratory. In order to fully utilize the potential of these machine tools, the CNC must include the ability to use multiple feedback sensors on each machine axis, incorporate corrections for quasistatic geometric errors (such as straightness, and squareness), be able to function over a relatively large range of motion (in excess of 60 inches per axis), and be able to produce motion updates at a rate sufficient to take advantage of the high bandwidth of the servo systems. At present, no commercially available CNC can presently meet all of the resolution, feed rate, and length of travel requirements of these machines. In order to minimize the complexity of the system, and thereby increase its reliability and maintainability, the programming was done in a high level language. The number of processors was kept as small as possible while still maintaining the performance requirements. We also used commercially available hardware in preference to building, in order to increase both reliability and maintainability. Special emphasis was given to making the CNC's operator interface as friendly as possible. We have completed a prototype control. We plan to install and test it in 1988. 4 figs.

Sweeney, D.J.; Weinert, G.F.

1988-06-23

132

Manufacturing of high-precision aspherical and freeform optics  

NASA Astrophysics Data System (ADS)

Aspherical and freeform optical elements have a large potential in reducing optical aberrations and to reduce the number of elements in complex high performance optical systems. However, manufacturing a single piece or a small series of aspherical and freeform optics has for long been limited by the lack of flexible metrology tools. With the cooperative development of the NANOMEFOS metrology tool by TNO, TU/e and VSL, we are able to measure the form of aspheres and freeforms up to 500 mm in diameter with an accuracy better than 10 nm rms. This development opened the possibility to exploit a number of iterative, corrective manufacturing chains in which manufacturing technologies such as Single Point Diamond Turning, freeform grinding, deterministic polishing and classical polishing are combined in an iterative loop with metrology tools to measure form deviation (like CMM, LVDT contact measurement, interferometry and NANOMEFOS). This paper discusses the potentials, limitations and differences of iterative manufacturing chains used by TNO in the manufacturing of high performance optics for astronomical purposes such as the anufacturing of the L2 of the Optical Tube Assembly of the four laser-guide star facility of the ESO VLT, Manufacturing of Aluminium freeforms mirrors for the SCUBA-2 instrument. Based on these results we will give an outlook into the new challenges and solutions in manufacturing high-precision optics.

Hoogstrate, André M.; van Drunen, Casper; van Venrooy, Bart; Henselmans, Rens

2012-09-01

133

A Concept for High Precision Astrometry with a Space Coronagraph  

NASA Astrophysics Data System (ADS)

High precision (micro-arcsecond) astrometry of nearby bright stars is theoretically (in the photon noise limit) possible with a space coronagraph with the addition of a wide field diffraction limited camera imaging an annulus of background stars around the central coronagraphic field. With micro arcsecond accuracy on a 1.4-m telescope, the mass of all planets that can be imaged by the coronagraph would be estimated. Simultaneous imaging and astrometric measurements would reduce the number of astrometric measurements necessary for mass determination, and reduce confusion between multiple planets and possible exozodiacal clouds in the coronagraphic image. While scientifically attractive, this measurement is technically very challenging, and must overcome astrometric error terms, which, in conventional telescopes, are several orders of magnitude above the photon noise limit. This paper investigates how some of these limitations could be overcome with new technical approaches, and identifies outstanding issues. The astrometric measurement is performed by simultaneously imaging background stars and diffraction spikes from the much brighter coronagraphic target on the same focal plane array. The diffraction spikes are generated by a series of small dark spots directly on the primary mirror to reduce sensitivity to optical and mechanical distortions. An example error budget is shown and discussed to identify major sources of error for a 1.4-m telescope imaging a 0.1 squaredeg field of view at the galactic pole. The relative measurements are made over an isoplanatic field much smaller than 0.1 square-degree, possibly as small as 4 arcsec and the photon noise limit within such small fields would be 30 uas, while a 0.3 deg isoplanatic angle would produce a photon limited accuracy of 0.125uas. Ultimately, the actual precision will be driven by wavefront and detector stability over long periods of time, and based on controlling a slew of instrumental errors.

Guyon, Olivier; Shao, M.

2010-01-01

134

High-precision Ice Surface Topography Mapping Using Radar Interferometry  

NASA Astrophysics Data System (ADS)

In May 2009 a new radar technique for mapping ice surface topography was demonstrated in a Greenland campaign as part of the NASA International Polar Year activities. This was achieved with the airborne Glacier and Ice Surface Topography Interferometer (GLISTIN-A): a 35.6 GHz single-pass interferometer. Although the technique of using radar interferometry for mapping terrain has been demonstrated before, this is the first such application at millimeter-wave frequencies. Instrument performance indicates swath widths over the ice between 5-7km, with height precisions ranging from 30cm-3m at a posting of 3m x 3m. However, for this application the electromagnetic wave will penetrate an unknown amount into the snow cover thus producing an effective bias that must be calibrated. To evaluate this, GLISTIN-A flew a coordinated collection with the NASA Wallops Airborne Topographic Mapper (ATM) on a transect from Greenland’s Summit to its West coast. Two field calibration sites were established at Colorado Institute for Research in Environmental Science’s Swiss Camp and the National Science Foundation’s Summit station. Additional collections entailed flying a mosaic over Jakobshavn glacier which was repeated after 6 days to reveal surface dynamics. Through detailed calibration and inter-sensor comparisons we were able to observe penetration biases and compare them with theoretical expectations. We also demonstrated GLISTIN-A’s capability to measure the topography of large glacier systems in a seamless fashion and accurately measuring volume changes with a high level of spatial detail. In particular, repeating the airborne campaigns to observe elevation changes over time will allow very accurate volume change measurements. Not only is this very important for mass balance studies to have a precise mass-loss estimate, but the spatial pattern can reveal ice dynamics effects and surface mass balance effects. In this manner a high resolution, high-precision topographic mapping capability is an ideal complement to the ICESat, ICESat II and Cryosat altimeters. Interpolating between the high-accuracy elevation profiles from altimeters such as the ATM or ICESat II with the high-resolution GLISTIN-A swath will enable detailed ice-surface topography maps and extended spatial coverage. The result is the potential for higher fidelity mass-balance estimates and improved observational coverage. Upgrades are currently underway to improve the performance and portability of GLISTIN-A such that, onboard a long-range aircraft this radar can map Greenland’s significant glaciers in a few days. The upgraded GLISTIN-A will be compatible with GlobalHawk installation making, Antarctica basin and coastal mapping feasible. GLISTIN will make more topographic products available to glaciologists, initially through dedicated airborne campaigns or ultimately, perhaps, as a satellite mission.

Moller, D.; Hensley, S.; Michel, T.; Rignot, E. J.; Simard, M.; Krabill, W. B.; Sonntag, J. G.

2010-12-01

135

DEVELOPMENT AND TESTING OF A NOVEL HIGH-PRECISION STEADY FLOW INSTRUMENT FOR UNSATURATED SOILS  

Microsoft Academic Search

This study is concerned with the development of a novel high-precision steady flow instrument applicable to common unsaturated soils such as clay, silt, sand, gravel soil and soft soil. The instrument consists of three parts: high-precision water pressure control system, high-precision air pressure control system and high-precision measurement system. Stepping motor was chosen as the source of water pressure power

Yong Sang; Longtan Shao; Xiaoxia Guo

2011-01-01

136

Ultra-High Precision, Ultra-Wide-Field Optical Photometry  

NASA Astrophysics Data System (ADS)

The low scintillation noise and the long continuous darkness are among the unique properties of the Dome-C site on the east Antarctic plateau. Ultra-high precision optical photometry is therefore among the techniques best suited for this particular site. We propose a telescope (ICE-T) optimized for ultra-high and ultra wide field photometry for Dome C. It consists of two 60cm optical ultra-wide-field Wynne-Schmidt telescopes and one 18cm narrow-field Maksutov spectrophotometric telescope on a single mount. ICE-T is currently a team effort of the German Alfred-Wegener-Institute for Polar Research, the Italian Universities of Padova and Perugia, the INAF Observatory Catania, and the Catalonian IEEC in Barcelona, Spain, and the AIP, with collaboration from the University of New South Wales, Australia and the University of St. Andrews, UK. In this paper, I discuss some of the many problems associated with sub-milli-mag photometry.

Strassmeier, K. G.

137

A Computer Controlled Precision High Pressure Measuring System  

NASA Astrophysics Data System (ADS)

A microcontroller (AT89C51) based electronics has been designed and developed for high precision calibrator based on Digiquartz pressure transducer (DQPT) for the measurement of high hydrostatic pressure up to 275 MPa. The input signal from DQPT is converted into a square wave form and multiplied through frequency multiplier circuit over 10 times to input frequency. This input frequency is multiplied by a factor of ten using phased lock loop. Octal buffer is used to store the calculated frequency, which in turn is fed to microcontroller AT89C51 interfaced with a liquid crystal display for the display of frequency as well as corresponding pressure in user friendly units. The electronics developed is interfaced with a computer using RS232 for automatic data acquisition, computation and storage. The data is acquired by programming in Visual Basic 6.0. This system is interfaced with the PC to make it a computer controlled system. The system is capable of measuring the frequency up to 4 MHz with a resolution of 0.01 Hz and the pressure up to 275 MPa with a resolution of 0.001 MPa within measurement uncertainty of 0.025%. The details on the hardware of the pressure measuring system, associated electronics, software and calibration are discussed in this paper.

Sadana, S.; Yadav, S.; Jha, N.; Gupta, V. K.; Agarwal, R.; Bandyopadhyay, A. K.; Saxena, T. K.

2011-01-01

138

High-precision heliostat for long-path light tracking  

NASA Astrophysics Data System (ADS)

A heliostat has been designed and built for use in optical remote sensing of the atmosphere. The heliostat uses two flat mirrors to track the sun and direct the sunlight to optical instruments. A stepper motor driven horizontal turntable is used to track the sun in azimuth and support an elevation assembly and a mechanical tower. The stepper motor driven elevation assembly drives an acquisition mirror that tracks the sun in elevation. This mirror directs the solar beam to a secondary mirror fixed on the mechanical tower. The secondary mirror then directs the solar beam along the axis of the tracker for use in measurements. A sensitive, high resolution CCD camera, receives a small part of the solar beam to analyze for fine servo-control. Ground based tests have demonstrated this instrument"s tracking capability for the sun, the moon, stars and for long pathlength sources. Presently, this system is coupled with a high-resolution Brucker 120M spectrometer used to obtain solar absorption spectra. The heliostat directs the solar radiation along the spectrometer optical axis. The pointing precision was measured to be better than 0.5 arcsec. A description of the heliostat is presented, as well as the results of ground tests.

Hawat, Tom; Stephen, Thomas M.; DeMaziere, Martine M.; Neefs, Eddy

2003-08-01

139

High precision metrology based microwave effective linewidth measurement technique.  

PubMed

A precision microwave effective linewidth measurement technique for magnetic samples has been developed. The measurement utilizes a high-Q cylindrical cavity that contains the sample of interest, a highly stable and programable static magnetic field source, a computer controlled network analyzer for cavity center frequency omega c and quality factor Qc determinations, and the standard metrological substitution ABA method for accurate relative omega c and Qc measurements. Sequential long term ABA measurements show that the time and temperature drifts and random errors are the dominant sources of error, with uncertainties in omega c/2pi and Qc in the range of 50 kHz and 25, respectively. The ABA method is applied to eliminate these drifts and minimize the random errors. For measurements over 25 ABA cycles, accuracy is improved to 0.14 kHz for omega c/2pi and 3 for Qc. The temperature variation over a single ABA cycle is generally on the order of 10(-3)-10(-5) degrees C and there is no need for any further temperature stabilization or correction measures. The overall uncertainty in the 10 GHz effective linewidth determinations for a 3 mm diam, 0.5 mm thick polycrystalline yttrium iron garnet (YIG) disk is 0.15 Oe or less, well below the intrinsic single crystal YIG linewidth. This represents a factor of 10 improvement in measurement accuracy over previous work. PMID:18052484

Mo, Nan; Green, Jerome J; Beitscher, Bailey A; Patton, Carl E

2007-11-01

140

Development of a custom high precision motion system to manipulate a 7 ton press  

NASA Astrophysics Data System (ADS)

In this paper ADC will discuss the design and test results for a custom high precision motion system to manipulate a 7 ton press (fabricated by Rockland Research Corporation). The system was installed at Beamline X17B2 NSLS for High Pressure Mineral Physics research. The beamline contains 0.391 mm of graphite filters, .500 mm silicon filter, and 2.0 mm of beryllium windows. The experimental apparatus consists of a large volume (~1 cu mm) multi-anvil press in either cubic or octahedral mode, providing pressures up to 29 GPa and temperatures up to 2000 K.

Deyhim, A.; Van Every, E.

2013-03-01

141

Quest for precision in hadronic cross sections at low energy: Monte Carlo tools vs. experimental data  

NASA Astrophysics Data System (ADS)

We present the achievements of the last years of the experimental and theoretical groups working on hadronic cross section measurements at the low-energy e + e - colliders in Beijing, Frascati, Ithaca, Novosibirsk, Stanford and Tsukuba and on ? decays. We sketch the prospects in these fields for the years to come. We emphasise the status and the precision of the Monte Carlo generators used to analyse the hadronic cross section measurements obtained as well with energy scans as with radiative return, to determine luminosities and ? decays. The radiative corrections fully or approximately implemented in the various codes and the contribution of the vacuum polarisation are discussed.

Actis, S.; Arbuzov, A.; Balossini, G.; Beltrame, P.; Bignamini, C.; Bonciani, R.; Carloni Calame, C. M.; Cherepanov, V.; Czakon, M.; Czy?, H.; Denig, A.; Eidelman, S.; Fedotovich, G. V.; Ferroglia, A.; Gluza, J.; Grzeli?ska, A.; Gunia, M.; Hafner, A.; Ignatov, F.; Jadach, S.; Jegerlehner, F.; Kalinowski, A.; Kluge, W.; Korchin, A.; Kühn, J. H.; Kuraev, E. A.; Lukin, P.; Mastrolia, P.; Montagna, G.; Müller, S. E.; Nguyen, F.; Nicrosini, O.; Nomura, D.; Pakhlova, G.; Pancheri, G.; Passera, M.; Penin, A.; Piccinini, F.; P?aczek, W.; Przedzinski, T.; Remiddi, E.; Riemann, T.; Rodrigo, G.; Roig, P.; Shekhovtsova, O.; Shen, C. P.; Sibidanov, A. L.; Teubner, T.; Trentadue, L.; Venanzoni, G.; van der Bij, J. J.; Wang, P.; Ward, B. F. L.; Was, Z.; Worek, M.; Yuan, C. Z.

2010-02-01

142

Closed loop high precision position control system with optical scale  

NASA Astrophysics Data System (ADS)

With the developments of science of art, there are more and more demands on the high resolution control of position of object to be controlled, such as lathe, product line, elements in the optical resonant cavity, telescope, and so on. As one device with high resolution, the optical scale has more and more utility within the industrial and civil applications. With one optical scale and small DC servo motor, one closed loop high resolution position control system is constructed. This apparatus is used to control the position of the elements of optical system. The optical scale is attached on the object or reference guide way. The object position is sampled by a readhead of non-contact optical encoder. Control system processes the position information and control the position of object through the motion control of servo DC motor. The DC motor is controlled by one controller which is connected to an industrial computer. And the micro frictionless slide table does support the smooth motion of object to be controlled. The control algorithm of system is PID (Proportional-Integral-Differential) methods. The PID control methods have well ROBUST. The needed data to control are position, velocity and acceleration of the object. These three parameters correspond to the PID characters respectively. After the accomplishments of hardware, GUI (Graphical user interface), that is, the software of control system is also programmed. The whole system is assembled by specialized worker. Through calibration experiments, the coefficients of PID are obtained respectively. And then the precision of position control of the system is about 0.1?m.

Ge, Cheng-liang; Liao, Yuan; He, Zhong-wu; Luo, Zhong-xiang; Huang, Zhi-wei; Wan, Min; Hu, Xiao-yang; Fan, Guo-bin; Liang, Zheng

2008-03-01

143

High precision metrology based microwave effective linewidth measurement technique  

SciTech Connect

A precision microwave effective linewidth measurement technique for magnetic samples has been developed. The measurement utilizes a high-Q cylindrical cavity that contains the sample of interest, a highly stable and programable static magnetic field source, a computer controlled network analyzer for cavity center frequency {omega}{sub c} and quality factor Q{sub c} determinations, and the standard metrological substitution ABA method for accurate relative {omega}{sub c} and Q{sub c} measurements. Sequential long term ABA measurements show that the time and temperature drifts and random errors are the dominant sources of error, with uncertainties in {omega}{sub c}/2{pi} and Q{sub c} in the range of 50 kHz and 25, respectively. The ABA method is applied to eliminate these drifts and minimize the random errors. For measurements over 25 ABA cycles, accuracy is improved to 0.14 kHz for {omega}{sub c}/2{pi} and 3 for Q{sub c}. The temperature variation over a single ABA cycle is generally on the order of 10{sup -3}-10{sup -5} deg. C and there is no need for any further temperature stabilization or correction measures. The overall uncertainty in the 10 GHz effective linewidth determinations for a 3 mm diam, 0.5 mm thick polycrystalline yttrium iron garnet (YIG) disk is 0.15 Oe or less, well below the intrinsic single crystal YIG linewidth. This represents a factor of 10 improvement in measurement accuracy over previous work.

Mo, Nan; Green, Jerome J.; Beitscher, Bailey A.; Patton, Carl E. [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)

2007-11-15

144

HIGH-PRECISION ASTROMETRY WITH A DIFFRACTIVE PUPIL TELESCOPE  

SciTech Connect

Astrometric detection and mass determination of Earth-mass exoplanets require sub-{mu}as accuracy, which is theoretically possible with an imaging space telescope using field stars as an astrometric reference. The measurement must, however, overcome astrometric distortions, which are much larger than the photon noise limit. To address this issue, we propose to generate faint stellar diffraction spikes using a two-dimensional grid of regularly spaced small dark spots added to the surface of the primary mirror (PM). Accurate astrometric motion of the host star is obtained by comparing the position of the spikes to the background field stars. The spikes do not contribute to scattered light in the central part of the field and therefore allow unperturbed coronagraphic observation of the star's immediate surroundings. Because the diffraction spikes are created on the PM and imaged on the same focal plane detector as the background stars, astrometric distortions affect equally the diffraction spikes and the background stars and are therefore calibrated. We describe the technique, detail how the data collected by the wide-field camera are used to derive astrometric motion, and identify the main sources of astrometric error using numerical simulations and analytical derivations. We find that the 1.4 m diameter telescope, 0.3 deg{sup 2} field we adopt as a baseline design achieves 0.2 {mu}as single measurement astrometric accuracy. The diffractive pupil concept thus enables sub-{mu}as astrometry without relying on the accurate pointing, external metrology, or high-stability hardware required with previously proposed high-precision astrometry concepts.

Guyon, Olivier; Eisner, Josh A.; Angel, Roger; Woolf, Neville J. [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States); Bendek, Eduardo A.; Milster, Thomas D. [College of Optical Sciences, University of Arizona, Tucson, AZ 85721 (United States); Mark Ammons, S. [Lawrence Livermore National Laboratory, Physics Division L-210, 7000 East Ave., Livermore, CA 94550 (United States); Shao, Michael; Shaklan, Stuart; Levine, Marie; Nemati, Bijan [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Pitman, Joe [Exploration Sciences, P.O. Box 24, Pine, CO 80470 (United States); Woodruff, Robert A. [2081 Evergreen Avenue, Boulder, CO 80304 (United States); Belikov, Ruslan, E-mail: guyon@naoj.org [NASA Ames Research Center, Moffett Field, CA 94035 (United States)

2012-06-01

145

A High-Speed and High-Precision Position Control Using Sliding Mode Compensator  

NASA Astrophysics Data System (ADS)

To achieve high-speed and high-precision position control for semiconductor product machines and industrial robots, the full-closed feedback control is applied. Many control methods have been proposed for such a system. In general, P,PI/I-PI control which is one of PID control is applied to a lot of industrial applications. However, in case of changing mechanical characters of control target, the parameters of P,PI/I-PI control have to be changed for keeping a good motion performance. In this paper, we propose a new P,PI/I-P control method which is with nonlinear compensator. The algorithm of nonlinear compensator is based on sliding mode control with chattering compensation. The effectiveness of proposed control method is evaluated by using full-closed single axis slider system via point to point control and contour control in the case of changing load. From the experimental results, the proposed control method has robustness in the case of changing acceleration/deceleration of control reference, changing load and low velocity contouring motion.

Tsuruta, Kazuhiro; Sato, Kazuya; Ushimi, Nobuhiro; Fujimoto, Takashi

146

Rigorous high-precision enclosures of fixed points and their invariant manifolds  

NASA Astrophysics Data System (ADS)

The well established concept of Taylor Models is introduced, which offer highly accurate C0 enclosures of functional dependencies, combining high-order polynomial approximation of functions and rigorous estimates of the truncation error, performed using verified arithmetic. The focus of this work is on the application of Taylor Models in algorithms for strongly non-linear dynamical systems. A method is proposed to extend the existing implementation of Taylor Models in COSY INFINITY from double precision coefficients to arbitrary precision coefficients. Great care is taken to maintain the highest efficiency possible by adaptively adjusting the precision of higher order coefficients in the polynomial expansion. High precision operations are based on clever combinations of elementary floating point operations yielding exact values for round-off errors. An experimental high precision interval data type is developed and implemented. Algorithms for the verified computation of intrinsic functions based on the High Precision Interval datatype are developed and described in detail. The application of these operations in the implementation of High Precision Taylor Models is discussed. An application of Taylor Model methods to the verification of fixed points is presented by verifying the existence of a period 15 fixed point in a near standard Henon map. Verification is performed using different verified methods such as double precision Taylor Models, High Precision intervals and High Precision Taylor Models. Results and performance of each method are compared. An automated rigorous fixed point finder is implemented, allowing the fully automated search for all fixed points of a function within a given domain. It returns a list of verified enclosures of each fixed point, optionally verifying uniqueness within these enclosures. An application of the fixed point finder to the rigorous analysis of beam transfer maps in accelerator physics is presented. Previous work done by Johannes Grote is extended to compute very accurate polynomial approximations to invariant manifolds of discrete maps of arbitrary dimension around hyperbolic fixed points. The algorithm presented allows for automatic removal of resonances occurring during construction. A method for the rigorous enclosure of invariant manifolds of continuous systems is introduced. Using methods developed for discrete maps, polynomial approximations of invariant manifolds of hyperbolic fixed points of ODEs are obtained. These approximations are outfit with a sharp error bound which is verified to rigorously contain the manifolds. While we focus on the three dimensional case, verification in higher dimensions is possible using similar techniques. Integrating the resulting enclosures using the verified COSY VI integrator, the initial manifold enclosures are expanded to yield sharp enclosures of large parts of the stable and unstable manifolds. To demonstrate the effectiveness of this method, we construct enclosures of the invariant manifolds of the Lorenz system and show pictures of the resulting manifold enclosures. To the best of our knowledge, these enclosures are the largest verified enclosures of manifolds in the Lorenz system in existence.

Wittig, Alexander N.

147

Ramsey Method of Separated Oscillatory Fields for High-Precision Penning Trap Mass Spectrometry  

SciTech Connect

Ramsey's method of separated oscillatory fields is applied to the excitation of the cyclotron motion of short-lived ions in a Penning trap to improve the precision of their measured mass values. The theoretical description of the extracted ion-cyclotron-resonance line shape is derived and its correctness demonstrated experimentally by measuring the mass of the short-lived {sup 38}Ca nuclide with an uncertainty of 1.1x10{sup -8} using the Penning trap mass spectrometer ISOLTRAP at CERN. The mass of the superallowed beta emitter {sup 38}Ca contributes for testing the theoretical corrections of the conserved-vector-current hypothesis of the electroweak interaction. It is shown that the Ramsey method applied to Penning trap mass measurements yields a statistical uncertainty similar to that obtained by the conventional technique but 10 times faster. Thus the technique is a new powerful tool for high-precision mass measurements.

George, S.; Blaum, K. [GSI, Planckstrasse 1, 64291 Darmstadt (Germany); Institut fuer Physik, Johannes Gutenberg-Universitaet, 55099 Mainz (Germany); Baruah, S.; Breitenfeldt, M.; Schweikhard, L. [Institut fuer Physik, Ernst-Moritz-Arndt-Universitaet, 17487 Greifswald (Germany); Blank, B. [Centre d'Etudes Nucleaires de Bordeaux-Gradignan, 33175 Gradignan Cedex (France); Hager, U. [Department of Physics, University of Jyvaeskylae, P.O. Box 35 (YFL), 40014 Jyvaeskylae (Finland); Herfurth, F.; Savreux, R.; Yazidjian, C. [GSI, Planckstrasse 1, 64291 Darmstadt (Germany); Herlert, A. [Physics Department, CERN, 1211 Geneva 23 (Switzerland); Kellerbauer, A. [Max-Planck Institut fuer Kernphysik, 69117 Heidelberg (Germany); Kluge, H.-J. [GSI, Planckstrasse 1, 64291 Darmstadt (Germany); Physikalisches Institut, Ruprecht-Karls-Universitaet, 69120 Heidelberg (Germany); Kretzschmar, M. [Institut fuer Physik, Johannes Gutenberg-Universitaet, 55099 Mainz (Germany); Lunney, D. [CSNSM-IN2P3-CNRS, 91405 Orsay-Campus (France); Schwarz, S. [NSCL, Michigan State University, East Lansing, Michigan 48824-1321 (United States)

2007-04-20

148

Precision optical slit for high heat load or ultra high vacuum  

DOEpatents

This invention relates generally to slits used in optics that must be precisely aligned and adjusted. The optical slits of the present invention are useful in x-ray optics, x-ray beam lines, optical systems in which the entrance slit is critical for high wavelength resolution. The invention is particularly useful in ultra high vacuum systems where lubricants are difficult to use and designs which avoid the movement of metal parts against one another are important, such as monochromators for high wavelength resolution with ultra high vacuum systems. The invention further relates to optical systems in which temperature characteristics of the slit materials is important. The present invention yet additionally relates to precision slits wherein the opposing edges of the slit must be precisely moved relative to a center line between the edges with each edge retaining its parallel orientation with respect to the other edge and/or the center line. 21 figures.

Andresen, N.C.; DiGennaro, R.S.; Swain, T.L.

1995-01-24

149

The Mainz high-precision proton form factor measurement  

NASA Astrophysics Data System (ADS)

Form factors offer a direct approach to fundamental properties of the nucleons like the radius and charge distribution. Renewed interest was stirred up by the 5 sigma discrepancy between a recent determination of the proton radius from the Lamb shift in muonic hydrogen and preceding electron scattering results. The low-q shape of the form factors might also contain a direct signal of a pion cloud around the nucleus and is a strong test of hadron models. In my talk, I will discuss the electron scattering experiment performed with the 3-spectrometer-facility of the A1 collaboration at MAMI in Mainz, Germany. The data set covers the Q^2-range from 0.004 to 1,(GeV/c)^2 and includes about 1400 separate cross section measurements, spanning the range of scattering angles from below 20^o to above 120^o at six beam energies between 180 and 855,eV, with statistical uncertainties below 0.4%. The 3-spectrometer-setup allowed for a simultaneous monitoring of the luminosity and overlapping and redundant measurements of the cross section to achieve stringent control over systematic uncertainties. Beam stabilization systems and redundant current measurements further limit systematic effects. The measured cross sections were analyzed with the standard Rosenbluth separation technique and by employing direct fits of a large set of form factor models. The high redundancy of the data set allowed us to extract the form factors up to 0.6,(GeV/c)^2 with very small uncertainties and to give a new, precise value for the proton radius from electron scattering. From the form factors, the charge distribution and Zemach moments were calculated. The latter constitute important input for the theoretical corrections of the muonic Lamb shift experiment. However, the revised values can not explain the discrepancy. Further possible explanations include higher order QED-corrections, vacuum effects or even physics beyond the standard model.

Bernauer, Jan

2011-04-01

150

High-precision measurement of chlorine stable isotope ratios  

USGS Publications Warehouse

We present an analysis procedure that allows stable isotopes of chlorine to be analyzed with precision sufficient for geological and hydrological studies. The total analytical precision is ?????0.09%., and the present known range of chloride in the surface and near-surface environment is 3.5???. As Cl- is essentially nonreactive in natural aquatic environments, it is a conservative tracer and its ??37Cl is also conservative. Thus, the ??37Cl parameter is valuable for quantitative evaluation of mixing of different sources of chloride in brines and aquifers. ?? 1993.

Long, A.; Eastoe, c. J.; Kaufmann, R. S.; Martin, J. G.; Wirt, L.; Finley, J. B.

1993-01-01

151

High precision ages from the Torres del Paine Intrusion, Chile  

NASA Astrophysics Data System (ADS)

The upper crustal bimodal Torres del Paine Intrusion, southern Chile, consists of the lower Paine-Mafic- Complex and the upper Paine-Granite. Geochronologically this bimodal complex is not well studied except for a few existing data from Halpern (1973) and Sanchez (2006). The aim of this study is to supplement the existing data and to constrain the age relations between the major magmatic pulses by applying high precision U-Pb dating on accessory zircons and 40Ar/39Ar-laser-step-heating-ages on biotites from the Torres del Paine Intrusion. The magmatic rocks from mafic complex are fine to medium-grained and vary in composition from quartz- monzonites to granodiorites and gabbros. Coarse-grained olivine gabbros have intruded these rocks in the west. The granitic body is represented by a peraluminous, biotite-orthoclase-granite and a more evolved leucocratic granite in the outer parts towards the host-rock. Field observations suggest a feeder-zone for the granite in the west and that the granite postdates the mafic complex. Two granite samples of the outermost margins in the Northeast and South were analyzed. The zircons were dated by precise isotope-dilution U-Pb techniques of chemically abraded single grains. The data are concordant within the analytical error and define weighted mean 206/238U ages of 12.59 ± 0.03 Ma and 12.58 ± 0.01 Ma for the two samples respectively. A 40Ar/39Ar-age for the second sample yield a date of 12.37 ± 0.11 Ma. Three 40Ar/39Ar -ages of biotites were obtained for rocks belonging to the mafic complex. A hbl-bio- granodiorite from the central part, approximately 150 m below the subhorizontal contact with the granite, gives an age of 12.81 ± 0.11 Ma. A hbl-bio-granodiorite and an olivine-gabbro west of the feeder-zone date at 12.42 ± 0.14 Ma and 12.49 ± 0.11 Ma, respectively. The obtained older age of 12.81 Ma for the granodiorite in the central part is consistent with structural relationships of brittle fracturing of the mafic complex by the granite and we conclude that some parts of the mafic complex were emplaced before the granite. The well defined 206/238U-age for zircons and the slightly younger 40Ar/39Ar -ages for biotites of both rock suites show that emplacement and cooling of the Torres del Paine Intrusion took place in a relatively short time-frame. Halpern, 1973, Geological Society of America Bulletin, 84/7: 2407-2422. Sanchez et.al., 2006. V SSAGI, Punta del Este, April 2006.

Michel, J.; Baumgartner, L.; Cosca, M.; Ovtcharova, M.; Putlitz, B.; Schaltegger, U.

2006-12-01

152

Optimal Kinematic Design of a Planar Parallel Manipulator with High Speed and High Precision  

Microsoft Academic Search

This paper introduces a novel 2-DOF high speed and high precision planar parallel manipulator. The manipulator consists of a moving platform that is connected to a fixed base by two limbs. Each limb is made up of one prismatic and four revolute joints and the two prismatic axes are arranged orthogonally. In contrast to conventional XY-tables, the manipulator investigated herein

Juan Li; Yanjie Liu; Chenqi Wang; Lining Sun

2006-01-01

153

A novel 2DOF planar parallel robot with high accelerate \\/ high precision  

Microsoft Academic Search

Orient to urgently demand for high speed and high precision robot of advanced manufacture fields such as packaging and assembly of micro-electronic manufactures, a novel 2-DOF planar parallel robot is presented, which is driven directly by linear voice coil motors. Firstly, the optimum configuration is obtained based on conditioning index of Jacobian. Then optimal dimension design is performed based on

Juan Li; Yanjie Liu; Lining Sun

2007-01-01

154

Toward the robust control of high-bandwidth high-precision flexible optical systems  

Microsoft Academic Search

It is well known that control-structure-interaction (CSI) phenomena limit the stability and performance of controlled flexible structures. Most CSI research focuses on rigid body control of flexible structures with relatively low closed loop control bandwidths. This research examines the CSI phenomena associated with high bandwidth high precision control of a reaction actuator mounted to a flexible support structure. In particular,

Kenneth Wayne Barker

1991-01-01

155

Precision Experiments With Stored And Cooled Highly Charged Ions  

SciTech Connect

Accumulation, storing and cooling techniques play an increasingly important role in many areas of science. These procedures can be applied in Penning traps and storage rings to ions. In this way, quantum electrodynamics can be tested in extreme electromagnetic fields by measuring hyperfine structure splittings. Lamb shifts, or g-factors in hydrogen-like heavy systems such as U91+ or Pb81+. In addition, fundamental constants or nuclear properties like the atomic mass can be determined. In the case of a radioactive ion, the fate of an individual ion, undergoing a nuclear decay, can be studied in detail by observing the disappearance of the signal of the mother and the appearance of that of the daughter isotope. Presently, the Highly-charged Ion TRAP (HITRAP) facility is being built up at GSI. Stable or radioactive highly charged ions are produced by colliding relativistic ions with a target. After electron cooling and deceleration in the storage ring ESR at GSI, these ions are ejected, decelerated further, and injected into a Penning trap where cooling to 4 K takes place. From there, the cooled highly charged ions such as hydrogen-like uranium are transferred at low energy to different experimental set-ups which are being built up by the international HITRAP Collaboration.

Kluge, H.-Juergen [Gesellschaft fuer Schwerionenforschung (GSI) Planckstrasse 1, D-64291 Darmstadt (Germany); Physikalisches Institut, Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg (Germany)

2006-11-07

156

Computation of High-Order Maps to Multiple Machine Precision  

Microsoft Academic Search

The Beam Dynamics simulation package in COSY INFINITY is built upon a differential algebra data type. With it, it is possible to compute transfer maps or arbitrary systems to arbitrary order. However, this data type is limited by the precision of the underlying floating point number model provided by the computer processor. We will present a method to extend the

Alexander Wittig; Martin Berz

2009-01-01

157

High-precision isotopic analysis of nanogram quantities of plutonium  

SciTech Connect

A surface ionization-diffusion-type ionization source that uses a rhenium filament overplated with platinum has been developed and optimized for 0.5- to 2-ng plutonium samples. This source is capable of measuring the /sup 240/Pu//sup 239/Pu atom ratio in nuclear-test-debris samples to 0.15% precision and accuracy at the 95% confidence level.

Perrin, R.E.; Knobeloch, G.W.; Armijo, V.M.; Efurd, D.W.

1984-06-01

158

High delay precision based on dynamic phase-shift for range-gated laser imaging technology  

NASA Astrophysics Data System (ADS)

The range-gated laser imaging technology has become a useful technique in many applications in recent years. In order to expand the range of imaging detection and improve the measurement range resolution of the imaging system, we used circular step advance delay sequence for the synchronous control. And we developed a method of using dynamic phase-shift technique in FPGA to improve the precision of the delay in the time sequence, which can make the precision of the delay stepper between the two adjacent frames less than global clock period of the FPGA and approach the limit of FPGA's operating frequency. That is to say, it can equivalently increase the clock frequency. Then we can effectively improve measurement range resolution of the imaging system. In this paper, we have studied how dynamic phase-shift technique can be equivalent to higher clock frequency and performed some experiments. We presented the structure of dynamic phase-shift technique used to improve the precision of delay in the synchronization control time sequence. And the simulation and experimental results are showed in this paper. The results demonstrate that using dynamic phase-shift technique in FPGA can make the precision of the delay between the ICCD's trigger pulse and the laser's trigger pulse reach 1ns, which means the resolution of measurement range can be 0.15m theoretically. The timing control signal with dynamic phase-shift technique designed in this paper can be widely used in range-gated imaging because of its high timing control precision and flexible parameter setting.

Cui, Wei; Fan, Song-tao; Wang, Xin-wei; Zhou, Yan

2013-09-01

159

An inexpensive precision constant current source for resistivity measurements in high Tc superconductors  

Microsoft Academic Search

The design and realization of an inexpensive, precision DC, constant current source for resistance measurement of high Tc superconductors are described. It is essentially based on easily available linear ICs and a precision voltage regulator. The circuit employs precision op.-amps (with low drift, low noise, etc.) and is more convenient to implement than earlier circuits. The whole unit can be

V. VIDYALAL; C. P. G. VALLABHAN

1993-01-01

160

High Precision Polarization Strategy for the Qweak Experiment  

NASA Astrophysics Data System (ADS)

The Qweak experiment in Hall C at Jefferson Lab is measuring the weak charge of the proton to an uncertainty of 4.1% by scattering longitudinally polarized electrons from protons in a liquid hydrogen target. The electron beam polarization is budgeted as the largest experimental systematic uncertainty of 1.5%. Aiming for a polarization measurement to within 1%, two independent polarimeters monitored the beam polarization by measuring the asymmetry of the polarized electron beam scattering either via the Møller or Compton process. The Møller polarimeter detects the pair of electrons scattered from a highly polarized thin iron foil through two identical calorimeters. However, it was limited to running at much lower currents and measurements are invasive to the experiment. The Compton polarimeter was commissioned to remove this limitation by using a high powered Fabry-Pérot cavity laser to provide a polarized photon source. The use of Compton scattering allows for non-invasive measurements and the ability to run at the same currents as the main experiment. The Compton scattered photons and electrons are detected independently. I will discuss the polarimetry strategy and preliminary polarization results for the Qweak experiment using these three techniques.

Cornejo, Juan Carlos

2012-10-01

161

High-Precision Determination of the Helium Abundance on Mars  

Microsoft Academic Search

We propose to use EUVE to observe Mars in late March 1999 in order to determine a precise value for the Martian helium abundance. An earlier measurement by EUVE yielded a marginal detection of the 58.4 nm line of neutral helium which led to an estimate of 4+\\/-2 ppm for the He mixing ratio. A new measurement at higher S\\/N

G. Randall Gladstone

1997-01-01

162

Design of a high-precision double crystal tunable monochromator  

SciTech Connect

This paper describes a UHV-compatible double crystal monochromator with independent drives for 2 linear and 2 angular crystal motions. Precise angular crystal positioning is achieved by using a spindle with a double gimbal mechanism, which converts linear motion of 0.1 micron to an angular motion of 0.042 arcsec. In order to decrease thermal distortions, the crystal intercepting white beam, is watercooled.

Shleifer, M.; Sharma, S.; Woodle, M.; Rotela, E.; Brite, C.

1993-11-01

163

Definition and use of the experimental sensible parameters to characterize sensitivity and precision of a generic oxygen optical sensor.  

PubMed

Experimental data, obtained with an oxygen optical sensor constituted by a polysulfone layer embedding ruthenium(II)(4,7-diphenyl-l,l0-phenanthroline)octylsulfate (Ru(dpp)OS), were rationalized by using the digital simulation technique and generalized for different sensors. The experimental, asymmetric, emission shape was used to define two sensible parameters, ASY (asymmetry factor) and DeltaI(%) (percent variation of emission intensity), to characterize the sensitivity of a generic oxygen optical sensor (represented by the Stern-Volmer constant, K'(sv)). Correlations between ASY and K'(sv) and between DeltaI(%) and K'(sv) were established, and a double working curve was proposed to evaluate with a single light emission measurement the K'(sv) value with the best precision. Sensitive membranes (-log K'(sv) = pK'(sv) < 0.5) had high precision only for low %O(2) values; poorly sensitive membrane (pK'(sv)> 2.5) had constant but scarce precisions in a large %O(2) interval. For %O(2) up to 21% (air) good values are pK'(sv)= 0.5-1.0. In order to monitor a wider %O(2) range, pK'(sv) = 1.5-2.0 are good choices. A simple mathematical model allowed one to estimate the oxygen diffusion coefficient inside the layer, D(O2), and its solubility in the polymer matrix, s(O2), from the simple measurement of the membrane thickness, response time, t(90), and luminescence lifetime. D(O2) = 2 x 10(-8) cm2 s(-1) and s(O2) = 2.2 x 10(-3) mol atm(-1) dm(-3) [corrected] were estimated for our membranes. The proposed working curves gave very good results even with literature data. PMID:18275221

Badocco, Denis; Pastore, Paolo

2008-02-15

164

High precision, accuracy, and resolution of 3D laser scanner employing pulsed time-of-flight measurement  

NASA Astrophysics Data System (ADS)

We present experimental results of a high-speed 3-D laser scanner developed for the European Space Agency within an activity dealing with a high precision relative attitude control sensor for formation flying. By employing pulsed-time-offlight measurement, we demonstrated sub-mm accuracy and precision as well as unprecedented resolution of single-shot measurements to natural targets at distances up to 150 m. The instrument is based on RIEGL's commercial terrestrial laser scanners with a scan range of 100° x 360° and a net measurement rate of 125 kHz. The system's performance is demonstrated with different test setups and potential fields of application are assessed.

Pfennigbauer, Martin; Ullrich, Andreas; Pereira Do Carmo, João

2011-05-01

165

Precision measurements of spin interactions with high density atomic vapors  

NASA Astrophysics Data System (ADS)

Polarized atomic vapors can be used to detect fields interacting with a spin. Recent advances have extended the sensitivity of atomic magnetometers to a level favorable for fundamental physics research, and in many cases the sensitivity approaches quantum metrology limits. In this thesis, we present a high density atomic K-3He comagnetometer, which features suppressed sensitivity to magnetic fields, but retains sensitivity to anomalous fields that couple differently than a magnetic field to electron and nuclear spins. The comagnetometer was used to measure interactions with a separate optically pumped 3He nuclear spin source. The 3He spin precession frequency in the comagnetometer was measured with a resolution of 18 pHz over the course of approximately one month, enabling us to constrain the anomalous spin-spin interaction between neutrons to be less than 2.5 x 10-8 of their magnetic or less than 2 x 10-3 of their gravitational interaction at a length scale of 50 cm. We set new laboratory bounds on the coupling strength of light pseudoscalar, vector and pseudovector particles to neutrons, and we consider the implications of our measurement to recently proposed models for unparticles and Goldstone bosons from spontaneous breaking of Lorentz symmetry. We also describe theoretically and experimentally a quantum non-demolition (QND) measurement of atomic spin in the context of radio frequency magnetometer with hot alkali-metal vapors. Using stroboscopic probe light we demonstrate suppression of the probe back-action on the measured observable, which depends on the probe duty cycle and on the detuning of the probe modulation frequency from twice the alkali Larmor frequency. We study the dependence of spin-projection noise on the polarization for atoms with spin greater than 1/2 and develop a theoretical model that agrees well with the data. Finally, it is shown theoretically that QND measurements can improve the long-term sensitivity of atomic magnetometers with non-linear relaxation.

Vasilakis, Georgios

166

Experimental and theoretical high energy physics  

NASA Astrophysics Data System (ADS)

We are carrying out a research program in high energy experimental particle physics. Studies of high energy hadronic interactions and leptoproduction processes continue using several experimental techniques. Progress has been made on the study of multiparticle production processes in nuclei. Ultra-high energy cosmic ray nucleus-nucleus interactions have been investigated by the Japanese American Cosmic Emulsion Experiment (JACEE) using balloon-borne emulsion chamber detectors. In the area of particle astrophysics, our studies of cosmic ray nuclear interactions have enabled us to make the world's most accurate determination of the composition of the cosmic rays above 10(13) eV. We have the only detector that can observe interaction vertices and identify particles at energies up to 10 to 15 eV. Our observations are getting close to placing limits on the acceleration mechanisms postulated for pulsars in which the spin and magnetic moment axes are at different angles. In June, 1989 approval was given by NASA for our participation in the Space Station program. The SCINATT experiment will make use of emulsion chamber detectors, similar to the planned JACEE hybrid balloon flight detectors. These detectors will permit precise determination of secondary particle charges, momenta and rapidities, and the accumulation of data will be at least a factor of 10 to 100 greater than in balloon experiments.

Boulware, David

167

High-precision analysis of SF6 at ambient level  

NASA Astrophysics Data System (ADS)

This work reports on the development of a technique for the precise analysis of ambient SF6. This technique, which involves a gas chromatograph/electron capture detector (GC-ECD) coupled with an Activated Alumina-F1 (AA-F1) column, performed well in the measurements, particularly in terms of accuracy, which complies with the World Meteorological Organization (WMO)-recommended compatibility of 0.02 ppt. Compared to the Porapak Q technique, we observed a sharper peak shape for the SF6 stream, which substantiates the improvement in the analytical precision. The traceability to the WMO scale was tested by calibrating the GC-ECD/AA-F1 analyser using five SF6 standards provided by the WMO/Global Atmosphere Watch (GAW) Central Calibration Laboratory (CCL) for SF6 (NOAA, United States of America). After calibration by various methods, the GC-ECD/AA-F1 accurately estimated the mole fraction of SF6 in the working standard prepared by the World Calibration Centre for SF6 operated by the Korea Meteorological Administration (KMA)/Korea Research Institute of Standards and Science (KRISS). Among the calibration methods, the two-point calibration method emerged to be the most economical procedure in terms of the data quality and measurement time. It was found that the KRISS scale of SF6/N2 was biased by 0.13 ppt when compared to the WMO scale of SF6/air; this bias is probably due to a different matrix.

Lim, J. S.; Moon, D. M.; Kim, J. S.; Yun, W.-T.; Lee, J.

2013-09-01

168

High-dose, high-precision treatment options for boosting cancer of the nasopharynx  

Microsoft Academic Search

Purpose: The aim of the study is to define the role and type of high-dose, high-precision radiation therapy for boosting early staged T1,2a, but in particular locally advanced, T2b-4, nasopharyngeal cancer (NPC).Materials and methods: Ninety-one patients with primary stage I–IVB NPC, were treated between 1991 and 2000 with 60–70Gy external beam radiation therapy (ERT) followed by 11–18Gy endocavitary brachytherapy (ECBT)

Peter C Levendag; Frank J Lagerwaard; Connie de Pan; Inge Noever; Arent van Nimwegen; Oda Wijers; Peter J. C. M Nowak

2002-01-01

169

High-current high-precision openable-core AC and AC\\/DC current transformers  

Microsoft Academic Search

The application of an electronic technique, which greatly increases the apparent permeability of the magnetic core of a current transformer, to high-current high-precision openable-core AC and AC\\/DC current transformers is described. The openable-core AC\\/DC current transformer can be used to measure accurately alternating current only or direct current only, or both alternating and direct currents simultaneously. Test results of two

Eddy So; Shiyan Ren; David A. Bennett

1993-01-01

170

Experimental investigation of a process cooling system retrofitted with HFC404A refrigerant for precise manufacturing application  

Microsoft Academic Search

Precise-manufacturing facilities, which emphasize accurate and stable machining of the working components to be used in semiconductor\\u000a industry, cannot function properly without appropriate and precise cooling. HCFC (hydro-chloro-floro-carbon) has been commonly\\u000a used as the coolant for precise manufacturing facilities; but it is facing the pressing schedule to be phased out. Additionally,\\u000a the dramatic variation of heat load during high-accuracy and

Fu-Jen Wang; Kuei-I Tsai; Yao-Jun Wang; Hao-Chuan Lee

2011-01-01

171

High-precision infra-red stellar interferometry  

NASA Astrophysics Data System (ADS)

This dissertation describes work performed at the Palomar Testbed Interferometer (PTI) during 1998 2002. Using PTI, we developed a method to measure stellar angular diameters in the 1 3 milli-arcsecond range with a precision of better than 5%. Such diameter measurements were used to measure the mass-radius relations of several lower main sequence stars and hence verify model predictions for these stars. In addition, by measuring the changes in Cepheid angular diameters during the pulsational cycle and applying a Baade-Wesselink analysis we are able to derive the distances to two galactic Cepheids (? Aql & ? Gem) with a precision of ˜10%; such distance determinations provide an independent calibration of the Cepheid period- luminosity relations that underpin current estimates of cosmic distance scales. Second, we used PTI and the adaptive optics facility at the Keck Telescope on Mauna Kea to resolve the low mass binary systems BY Dra and GJ 569B, resulting in dynamical mass determinations for these systems. GJ 569B most likely contains at least one sub-stellar component, and as such represents the first dynamical mass determination of a brown dwarf. Finally, a new observing technique, dual star phase referencing, was developed and demonstrated at PTI. Phase referencing allows interferometric observations of stars previously too faint to observe, and is a prerequisite for large-scale interferometric astrometry programs such as the one planned for the Keck Interferometer; interferometric astrometry is a promising technique for the study of extra-solar planetary systems, particularly ones with long-period planets.

Lane, Benjamin F.

2003-08-01

172

Adjustment Procedure of a High Precision Deployable Mesh Antenna for MUSES-B Spacecraft  

Microsoft Academic Search

In this paper, a precise on-ground adjustment procedure of a high precision deployable space antenna which has to keep the required surface accuracy in space environment, such as zero gravity, high vacuum, etc., is investigated. For space structure systems in the relatively near future the active shape control technology in orbits is still not matured, and it is important to

Masaki Tabata; M. C. Natori; Takanori Tashima; Toshio Inoue

1997-01-01

173

High precision Hg isotope analysis of environmental samples using gold trap-MC-ICP-MS  

Microsoft Academic Search

Precise and accurate analysis of Hg isotope compositions in environmental samples can be an invaluable tool in investigating Hg cycles in the environment. We have developed a method for high precision Hg isotope analysis using a gold trap sample introduction system coupled to a Thermo Finnigan MC-ICP-MS. Environmental samples were pyrolyzed at high temperature and Hg released from the samples

Qianli Xie; Shengyong Lu; Doug Evans; Peter Dillon; Holger Hintelmann

2005-01-01

174

High precision electromagnetic field sensors for monitoring communications devices  

Microsoft Academic Search

Presents computer simulation and experimental aspects towards the development of passive, all-dielectric, electro-optic and magneto-optic sensors based an the Pockel's and Faraday effects, respectively. Semiconductor crystals, laser diode and fibre optic technology will enable the measurement of electromagnetic fields from communications devices at frequencies up to 2 GHz

M. BERWICKt; S. R. Cvetkovic; F. V. Cecelia; W. Balachandran

1994-01-01

175

High precision silicon piezo resistive SMART pressure sensor  

NASA Astrophysics Data System (ADS)

Instruments for test and calibration require a pressure sensor that is precise and stable. Market forces also dictate a move away from single measurand test equipment and, certainly in the case of pressure, away from single range equipment. A pressure `module' is required which excels in pressure measurement but is interchangble with sensors for other measurands. A communications interface for such a sensor has been specified. Instrument Digital Output Sensor (IDOS) that permits this interchanagability and allows the sensor to be inside or outside the measuring instrument. This paper covers the design and specification of a silicon diaphragm piezo resistive SMART sensor using this interface. A brief history of instrument sensors will be given to establish the background to this development. Design choices of the silicon doping, bridge energisation method, temperature sensing, signal conversion, data processing, compensation method, communications interface will be discussed. The physical format of the `in-instrument' version will be shown and then extended to the packaging design for the external version. Test results will show the accuracy achieved exceeds the target of 0.01%FS over a range of temperatures.

Brown, Rod

2005-01-01

176

Calculated thermal behavior of ventilated high precision radio telescopes  

NASA Astrophysics Data System (ADS)

Radio telescopes that operate at millimeter and sub-millimeter wavelengths need a reflector-surface precision of a few tens of microns and a pointing accuracy of a few arcseconds. When built in a conventional way from steel and aluminum, as in the case of larger-diameter telescopes, thermal control must be applied to reduce temperature-induced deformations, in particular of the reflector backup structure. We illustrate that it is possible to make model calculations - for instance, during the design phase - that simulate the thermal behavior and the operation of a telescope when servo-loop-controlled ventilation or climatization (air-conditioned ventilation) of the backup structure is applied. We explain the technique of model calculations, and present as an example the calculated thermal behavior of a ventilated 64-m-diameter telescope and of the climatized 30-m IRAM telescope. It is explained that the thermal control of a telescope mount is less demanding if frequent pointing corrections can be made.

Greve, A.; Bremer, M.

2006-06-01

177

Rotor crack detection based on high-precision modal parameter identification method and wavelet finite element model  

NASA Astrophysics Data System (ADS)

In this paper, a new method based on high-precision modal parameter identification method and wavelet finite element (WFE) model is presented to determine the depth and location of a transverse surface crack in a rotor system. The rotor system is modeled using finite element method of B-spline wavelet on the interval (FEM BSWI), while the crack is equivalent as a weightless rotational spring. Additionally, a novel method based on empirical mode decomposition (EMD) and Laplace wavelet is proposed to acquire modal parameters with high precision, which is implemented to improve the precision of crack identification. By providing the first three natural frequencies, contours for the specified natural frequency are plotted in the same coordinate, and the intersection of the three curves predicts the crack location and size. The experimental results indicate that the proposed method can accurately identify the position and depth of different cracks. The effectiveness and reliability of the proposed method is verified.

Dong, H. B.; Chen, X. F.; Li, B.; Qi, K. Y.; He, Z. J.

2009-04-01

178

Adding Precise Nanoliter Volume Capabilities to Liquid-Handling Automation for Compound Screening Experimentation  

Microsoft Academic Search

Miniaturizing experimental sample volumes to the nanoliter volume range is one of the most economical ways to perform mid- and high-throughput compound screening experiments. Existing automation platforms for nanoliter fluid handling can be bulky, expensive, and require periodic calibration to provide consistent liquid dispensing. In addition, even with frequent calibration, significant instrument-to-instrument variation in low-volume dispensing can occur between different

Tal V. Murthy; Doug Kroncke; Paul D. Bonin

2011-01-01

179

High-Precision Diagnosis of Malfunctioning Apparatus allowed by Serendipity  

NASA Astrophysics Data System (ADS)

``An electric brake has a resistance of 376 ohms and operates at 90 volts. If the only supply available is 115 volts, show how the brake can still be made to work.'' The preceding exercise is the theoretical counterpart of a practical problem involving a platform elevator for the physically-challenged. The elevator brake had been inoperable for a considerable period due to an intractable ambiguity, even after two independent technicians working together had established that some components might have been installed improperly. It so happened that the author was on handfootnotetextnote: during a visit to the educational institution concerned. and he suggested an experimental approach for a remedy that could be checked if some standard equipment were provided. Once this item was located, his testing confirmed the viability of the proposed remedy, resulting in a prompt repair and a much-needed return to service. This good outcome was achieved by integrating theory and practice to produce maximum synergy. )

Shaibani, Saami J.

2010-02-01

180

Versatile integrated tunable diode laser system for high precision - Application for ambient measurements of OCS  

Microsoft Academic Search

A versatile and integrated tunable diode laser system for high precision measurements of the important sulfur gas carbonyl sulfide is described. Some of the major factors affecting tunable diode laser measurement precision as well as accuracy are addressed explicitly, and a number of new features for increased system control and versatility have been implemented. The system provides the capability for

Alan Fried; Bruce Henry; Jack Fox; James R. Drummond

1991-01-01

181

High-precision location of lightning-caused distribution faults  

Microsoft Academic Search

Highly accurate distribution system fault location is possible by combining lightning location data with fault monitor disturbance data and distribution feeder location (GIS) data. A 13-month monitoring and investigation program (June 1998-July 1999) was conducted on a rural electric cooperative distribution system to test the concept

J. G. Kappenman; M. E. Gordon; T. W. Guttormson

2001-01-01

182

Pointing Control System for a High Precision Flight Telescope  

SciTech Connect

A pointing control system is developed and tested for a flying gimbaled telescope. The two-axis pointing system is capable of sub-microradian pointing stability and high accuracy in the presence of large host vehicle jitter. The telescope also has high agility--it is capable of a 50-degree retarget (in both axes simultaneously) in less than 2 seconds. To achieve the design specifications, high-accuracy, high-resolution, two-speed resolvers were used, resulting in gimbal-angle measurements stable to 1.5 microradians. In addition, on-axis inertial angle displacement sensors were mounted on the telescope to provide host-vehicle jitter cancellation. The inertial angle sensors are accurate to about 100 nanoradians, but do not measure low frequency displacements below 2 Hz. The gimbal command signal includes host-vehicle attitude information, which is band-limited. This provides jitter data below 20 Hz, but includes a variable latency between 15 and 25 milliseconds. One of the most challenging aspects of this design was to combine the inertial-angle-sensor data with the less perfect information in the command signal to achieve maximum jitter reduction. The optimum blending of these two signals, along with the feedback compensation were designed using Quantitative Feedback Theory.

BENTLEY,ANTHONY E.; WILCOXEN,JEFFREY LEE

2000-12-01

183

A High Precision Constant Current Source Applied in LED Driver  

Microsoft Academic Search

LED is generally driven by constant current because the color and brightness of LED are directly related to their forward current. The current accuracy is a very important index for a high performance LED driver. In this paper, a constant current source applied in LED driver is proposed to improve the accuracy of the LED current. The constant current source

Hongtao Mu; Li Geng; Jun Liu

2011-01-01

184

High Precision Iron Isotope Measurements With High Mass Resolution MC-ICPMS  

NASA Astrophysics Data System (ADS)

The interest in Fe isotope compositions in Geo- and Cosmoscience has increased within the last few years, since improved analytical techniques led to the discovery of natural mass dependent isotope fractionation. Relative mass differences of the various Fe isotopes are relatively small, resulting in small isotopic fractionations (typically in the range of a few per mill), requiring precise and reliable methods to detect natural isotope fractionations. The preferred techniques for such measurements are thermal ionization mass spectrometry (TIMS) and multiple collector inductively coupled plasma mass spectrometry (MC-ICPMS). Compared to TIMS, MC-ICPMS has a larger mass bias, about 3% per a.m.u for Fe. However the mass bias is stable, at least for short term measurements, and fast sample/standard switching is possible. Unfortunately, most Fe-isotope peaks suffer from molecular interferences, e.g. 40Ar14N on 54Fe, 40Ar16O on 56Fe, 40Ar16OH on 57Fe, and 40Ar18O on 58Fe, respectively. These interferences can effectively be excluded by high mass resolution. The Thermo Finnigan NEPTUNE is the first commercial high mass resolution MC-ICPMS instrument that can perform high mass resolution measurements with flat top peaks on multiple collectors. The dynamic range of the NEPTUNE's current amplifiers is extended to 50V, improving the precision for large isotopic ratio measurements (e.g. 58Fe/56Fe). Samples were introduced either using a dual glass spray chamber, giving a high signal stability and low memory, or using a CETAC Aridus desolvating nebulizer, that gave a 3-4 fold increase in sensitivity (ca. 10V/ppm on 56Fe in high resolution mode). Only about 500ng of Fe is necessary for a high precision measurement (with internal precision of better than 20ppm 1RSD for 56Fe/54Fe and 57Fe/54Fe). The external precision of the method was tested by measuring several samples with various isotopic compositions. Accuracy was checked by adding variable amounts of an isotopically enriched (in 57Fe) tracer to the standard (IRMM014). All samples were measured using an alternating sample - standard method. In high mass resolution mode blank subtraction has only to be performed if there are large concentration differences between the standard and the sample solutions, since the small blank is mainly iron itself and isotopic variations are rather small. The reproducibility of the delta 56Fe/54Fe and delta 57Fe/54Fe was below 0.1 \\permil (1RSD). The results for the spiked samples agreed within uncertainties with the values calculated from the certified spike values. For external mass bias correction, Ni was added to some sample solutions. For purified samples this correction method did not significantly improve precision and accuracy. However, for matrix-containing samples this technique could be used to some extent to correct for matrix introduced instrumental drift.

Weyer, S.; Johannes, S.; Gerhard, J.

2001-12-01

185

High precision Wind measurements in the upper Venus atmosphere  

Microsoft Academic Search

We will present high accuracy measurements of line-of-sight wind velocities in the upper Venus atmosphere and models of the implied global circulation. The measurements were performed using the NASA\\/GSFC Infrared Heterodyne Spectrometer at the NASA IRTF. Thermospheric altitudes between 100 and 120 km were probed using 12C16O2 solar-pumped, non-thermal emission. The observed signal-to-noise allowed determination of line center frequencies to

F. Schmuelling; J. Goldstein; T. Kostiuk; T. Hewagama; D. Zipoy

2000-01-01

186

Precise Measurement of Atmospheric Gamma Rays at High Altitude  

Microsoft Academic Search

We have been observing the atmospheric gammaray spectrum from 30 GeV to 10 TeV for many years with the emulsion chamber at balloon altitude. Atmospheric gamma rays at high altitude of several g\\/cm2 are almost produced by a single interaction of primary cosmic rays, and useful to interpret the various cosmic-ray phenomena inside the atmosphere. Especially, more conclusive understanding for

T. Kobayashi; Y. Komori; K. Yoshida; J. Nishimura

2001-01-01

187

Toward the robust control of high bandwidth high precision flexible optical systems  

NASA Astrophysics Data System (ADS)

It is well known that control structure interaction (CSI) phenomena limit the stability and performance of controlled flexible structures. Most CSI research focuses on rigid body control of flexible structures with relatively low closed loop control bandwidths. This research examines the CSI phenomena associated with high bandwidth high precision control of a reaction actuator mounted to a flexible support structure. In particular, control structure interaction using a high gain porportional integral derivative (PID) controller is examined as it relates to certain design parameters. Rapid small angle line-of-sight repositioning and precision line-of-sight stabilization against a variety of disturbances are performed using both a single and multimode model. The single flexible mode model consists of a three-mass lightly damped translating system, referred to as the modified benchmark model. The multimode model consists of a single-axis reaction steering mirror mounted to the tip of a flexible truss-like support structure. Control-structure-interaction analysis of the reaction actuator control problem is performed first on the single-mode model as a function of flexible mode location, then with the multimode model as a function of inertial and elastic coupling between the reaction steering mirror and the flexible support structure. The analysis describes the control-structure-interaction effects on both stability and performance of a high gain line-of-sight PID controller.

Barker, Kenneth W.

188

Biocompatible, high precision, wideband, improved Howland current source with lead-lag compensation.  

PubMed

The Howland current pump is a popular bioelectrical circuit, useful for delivering precise electrical currents. In applications requiring high precision delivery of alternating current to biological loads, the output impedance of the Howland is a critical figure of merit that limits the precision of the delivered current when the load changes. We explain the minimum operational amplifier requirements to meet a target precision over a wide bandwidth. We also discuss effective compensation strategies for achieving stability without sacrificing high frequency output impedance. A current source suitable for Electrical Impedance Tomography (EIT) was simulated using a SPICE model, and built to verify stable operation. This current source design had stable output impedance of 3.3 M? up to 200 kHz, which provides 80 dB precision for our EIT application. We conclude by noting the difficulty in measuring the output impedance, and advise verifying the plausibility of measurements against theoretical limitations. PMID:23853280

Tucker, A S; Fox, R M; Sadleir, R J

2013-02-01

189

High-precision time and frequency measurement method combining time-space conversion and different frequency phase detection  

NASA Astrophysics Data System (ADS)

According to the time & space conversion relations and different frequency phase detection principle, an ultra-high precision time & frequency measurement method is proposed in this paper. The higher accuracy and stability of the speed of light and electromagnetic signals during the transmission in space or a specific medium enable the measurement of short time interval which uses the coincidence detection of signal's transmission delay in length. The measurement precision better than 10 picoseconds can be easily obtained. The method develops the length vernier utilizing the stability of signal's transmission delay, minimizes the fuzzy region of phase coincidence between the standard frequency signal and the measured signal, approaches the best phase coincidences and therefore improves the measurement precision which is higher than the precision provided by the traditional methods based on frequency processing. Besides, the method costs less than the traditional methods and can also solve the problem of the measurement of super-high frequency. Experimental results show the method can improve the measurement precision to 10-12/s in the time & frequency domain.

Du, BaoQiang; Wang, YanFeng; Cui, GuangZhao; Guo, ShuTing; Dong, ShaoFeng; Liu, Dan

2013-10-01

190

High-precision thermodynamics and Hagedorn density of states  

SciTech Connect

We compute the entropy density of the confined phase of QCD without quarks on the lattice to very high accuracy. The results are compared to the entropy density of free glueballs, where we include all the known glueball states below the two-particle threshold. We find that an excellent, parameter-free description of the entropy density between 0.7T{sub c} and T{sub c} is obtained by extending the spectrum with the exponential spectrum of the closed bosonic string.

Meyer, Harvey B. [Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2009-09-01

191

High Precision SC Cavity alignment Measurements with Higher Order Modes  

SciTech Connect

Experiments at the FLASH linac at DESY have demonstrated that the higher order modes (HOMs) induced in superconducting cavities can be used to provide a variety of beam and cavity diagnostics. The centers of the cavities can be determined from the beam orbit which produces minimum power in the dipole HOM modes. The phase and amplitude of the dipole modes can be used as a high resolution beam position monitor. For most superconducting accelerators, the existing HOM couplers provide the necessary signals, and the downmix and digitizing electronics are straightforward, similar to those for a conventional BPM.

Molloy, Stephen; Frisch, Josef; Hendrickson, Linda; McCormick, Douglas; May, Justin; Ross, Marc; Smith, Tonee; /SLAC; Eddy, Nathan; Nagaitsev, Sergei; /Fermilab; Baboi, Nicoleta; Hensler, Olaf; Petrosyan, Lyudvig; /DESY; Napoly, Olivier; Paparella, Rita; Simon, Claire; /DSM, DAPNIA, Saclay

2007-06-14

192

A high-precision pulse-width modulator source.  

SciTech Connect

A novel high-resolution pulse-width modulator (PWM) is being developed for a new digital regulator for the Advanced Photon Source power converters. The circuit features 82-ps setability over an 80-{micro}s range. Our application requires a 50-{micro}s fill-scale range; therefore the 82-ps setability is equivalent to better than 19 bits. The circuit is presently implemented as a VME module and is an integral part of the digital regulator prototype. The design concept and performance results will be presented.

Lenkszus, F.; Laird, R.

1999-09-30

193

High pulse rate and pileup handling in precision RBS  

NASA Astrophysics Data System (ADS)

Recording RBS spectra at the fastest possible rate presents obvious advantages. Speed is, moreover, a must when RBS is carried out simultaneously with NRA, when high-Z thick targets are analyzed, like YBaCuO, and a very large number of pulses must be processed for recording with sufficient statistics the narrow high-energy region of interest, when kinetics measurements are carried out in situ, the total time available for the measurements being limited by the physical process under study, etc. We present here the first results of a systematic search for increasing counting rates in RBS while keeping pileup-induced spectrum distortions within acceptable levels. The pileup-handling properties of the fastest available spectroscopy amplifiers were characterized. A probabilistic model was developed of the residual pileup process due to the pairs of pulses not resolved by the pileup rejection system. The corresponding algorithm implemented with the GENPLOT program with RUMP input-output format may be used to clean up the spectra from the residual pileup. We present examples of spectra recorded with counting rates up to 43000 counts/s and treated successfully with this algorithm. The still unsolved problems and possible remedies are discussed.

Amsel, G.; Girard, E.; Vizkelethy, G.; Battistig, G.; Girard, Y.; Szilágyi, E.

1992-02-01

194

High integrity GPS/INS filter for precise relative navigation  

NASA Astrophysics Data System (ADS)

A GPS/INS filter design for absolute and relative state estimation is discussed. The GPS code and Doppler measurements are used for absolute state estimation while the GPS carrier phase and Doppler measurements are used for relative state estimation. Real-time results obtained from a Hardware-in-the-Loop Simulation and actual F-18 flight tests are presented. To ensure accurate state estimation, the observability of the GPS/INS system is analyzed analytically when the system is at rest and during maneuvers. The system observability enhancement during two different maneuvers is discussed. Simulation results illustrating the observability of the system during the different stages of the GPS/INS system operation are also presented. To allow successful use of the high-accuracy carrier phase measurements, two methods for resolving GPS integer ambiguity are introduced. The first combines an efficient method for obtaining the admissible integer ambiguity hypotheses within a probabilistic volume with an integer hypothesis testing method to reduce the convergence time with high probability to the GPS carrier phase integers. The second GPS integer ambiguity resolution method is based on a log-formulation of the Multiple Hypothesis Wald Sequential Probability Test (MHWSPT). The computational time requirement of the latter method is shown to be smaller than the former method. Real-time results are presented to show the performance of the two methods introduced.

Abdel-Hafez, Mamoun F.

195

Design approach to a high-precision reflectometer for component study evaluation  

Microsoft Academic Search

High-power lasers require beam directing optics with high damage thresholds. To achieve this, coatings with very high reflectivity and low absorption are being developed by many investigators. This paper describes a reflectometer for measuring these high reflectances to a very high precision. Parameters investigated for this design are source stability, detector limitations, data collection schemes, and the basic optical configuration.

C. Gokay; K. Harding; J. Loomis; J. Marcheski

1981-01-01

196

High precision trace neutron transmutation doping of detector-grade high resistance zone-refined silicon mono-crystal.  

National Technical Information Service (NTIS)

The technique of high precision trace neutron transmutation doping of detector grade high resistance zone-refined Si mono-crystal is introduced. The key technique is to precisely control the doping element. It includes the determination of (rho)(sub 0) va...

B. Chen J. Gao X. Gao H. Dong S. Li

1993-01-01

197

High-precision high-sensitivity clock recovery circuit for a mobile payment application  

NASA Astrophysics Data System (ADS)

This paper presents a fully integrated carrier clock recovery circuit for a mobile payment application. The architecture is based on a sampling-detection module and a charge pump phase locked loop. Compared with clock recovery in conventional 13.56 MHz transponders, this circuit can recover a high-precision consecutive carrier clock from the on/off keying (OOK) signal sent by interrogators. Fabricated by a SMIC 0.18-?m EEPROM CMOS process, this chip works from a single power supply as low as 1.5 V Measurement results show that this circuit provides 0.34% frequency deviation and 8 mV sensitivity.

Lichong, Sun; Wenliang, Ren; Na, Yan; Hao, Min

2011-05-01

198

Development of Large Current High Precision Pulse Power Supply  

NASA Astrophysics Data System (ADS)

JAEA and KEK are jointly constructing a high intensity proton accelerator project J-PARC. Its main accelerator is 3GeV synchrotron. Its injection bump magnets, especially horizontal paint bump magnets, are excited by large pulse currents. Their rated currents are over 10kA and pulse widths are about 1ms. Tracking errors are required to be less than 1%. Multiple connected two-quadrant IGBT choppers are adopted for their power supplies. Their output currents are controlled by feedback control with minor loop voltage control (m-AVR). When output current of a chopper intermits at small current, its output voltage rises up and current control becomes difficult. In this paper response of m-AVR and output voltage characteristics at current intermittent region are studied and an improved control scheme is proposed. The performance is confirmed by a test.

Takayanagi, Tomohiro; Koseki, Shoichiro; Kubo, Hiroshi; Katoh, Shuji; Ogawa, Shinichi

199

Calibration, registration, and synchronization for high precision augmented reality haptics.  

PubMed

In our current research we examine the application of visuo-haptic augmented reality setups in medical training. To this end, highly accurate calibration, system stability, and low latency are indispensable prerequisites. These are necessary to maintain user immersion and avoid breaks in presence which potentially diminish the training outcome. In this paper we describe the developed calibration methods for visuo-haptic integration, the hybrid tracking technique for stable alignment of the augmentation, and the distributed framework ensuring low latency and component synchronization. Finally, we outline an early prototype system based on the multimodal augmented reality framework. The latter allows colocated visuo-haptic interaction with real and virtual scene components in a simplified open surgery setting. PMID:19008561

Harders, Matthias; Bianchi, Gérald; Knoerlein, Benjamin; Székely, Gábor

200

High-precision measurements on a compact antenna test range  

NASA Astrophysics Data System (ADS)

A comparison is presented of results of antenna measurements on a compact antenna test range (CATR) with those on an outdoor range. It is determined that direct uncorrected CATR measurements are reliable, mainly due to the excellent phase characteristics of the CATR and the very low levels of stray radiation in the test zone of the anechoic chamber. It is shown that the uncorrected CATR data can be interpreted directly (beam width, gain, sidelobe levels, and x-pol) in antenna design and diagnostic methods. It is also shown that a powerful correction algorithm can be applied for measurements of oversized antennas where the test antenna occupies more than 50 percent of the aperture of the CATR (in linear dimensions), or for high-performance measurements. This algorithm is found to converge very fast, and there is no need to handle the complete plane-wave spectrum of the antenna but only the deviations of the CATR field spectrum.

Beeckman, P. A.

1983-09-01

201

High Precision SC Cavity Diagnostics with HOM Measurements  

SciTech Connect

Experiments at the FLASH linac at DESY have demonstrated that the Higher Order Modes induced in Superconducting Cavities can be used to provide a variety of beam and cavity diagnostics. The centers of the cavities can be determined from the beam orbit which produces minimum power in the dipole HOM modes. The phase and amplitude of the dipole modes can be used as a high resolution beam position monitor, and the phase of the monopole modes to measure the beam phase relative to the accelerator RF. Beam orbit feedback which minimizes the dipole HOM power in a set of structures has been demonstrated. For most SC accelerators, the existing HOM couplers provide the necessary signals, and the down mix and digitizing electronics are straightforward, similar to those for a conventional BPM.

Frisch, Josef; Hendrickson, Linda; McCormick, Douglas; May, Justin; Molloy, Stephen; Ross, Marc; /SLAC

2006-08-18

202

High Precision Superconducting Cavity Diagnostics With Higher Order Mode Measurements  

SciTech Connect

Experiments at the FLASH facility at DESY have demonstrated that the higher order modes induced in superconducting cavities can be used to provide a variety of beam and cavity diagnostics. The axes of the modes can be determined from the beam orbit that produces minimum power in the dipole HOM modes. The phase and amplitude of the dipole modes can be used to obtain high resolution beam position information, and the phase of the monopole modes to measure the beam phase relative to the accelerator rf. For most superconducting accelerators, the existing higher order mode couplers provide the necessary signals, and the downmix and digitizing electronics are straightforward, similar to those for a conventional beam position monitor.

Molloy, S.; Frisch, J.; McCormick, D.; May, J.; Ross, M.; Smith, T.; /SLAC; Baboi, N.; Hensler, O.; Petrosian, L.; /DESY; Napoly, O.; Paparella, R.C.; Simon, C.; /Saclay; Eddy, N.; Nagaitsev, S.; Wendt, M.; /Fermilab

2007-02-12

203

Fabrication of ultrafine nanostructures with single-nanometre precision in a high-resolution transmission electron microscope  

NASA Astrophysics Data System (ADS)

Highly ordered ultrafine nanostructures (feature size <10 nm) have been successfully fabricated with single-nanometre precision using a convergent electron beam (CEB) in a high-resolution transmission electron microscope (HRTEM). This approach can be widely applied to inorganic solid-state materials including insulators, semiconductors and metals. The feature size can be precisely controlled by the probe size and the irradiation time. The formation mechanism of nanostructures fabricated by CEB has been discussed in terms of knock-on damage and the beam heating effect. On the basis of the experimental results of electron energy-loss spectroscopy (EELS), finite element thermal analysis reveals that the heating effect of the high-energy electron beam is negligible in inorganic solid-state materials, and the sculpting of nanostructures is predominated by the knock-on damage or ionization of high-energy electrons.

Zhang, Jingmin; You, Liping; Ye, Hengqiang; Yu, Dapeng

2007-04-01

204

High Precision Spectroscopy of Lambda-Hypernuclei beyond p-shell using electromagnetic probe at Jefferson Lab  

SciTech Connect

The first experiment E89-009/HNSS has made the key demonstration and feasibility test on the electroproduction of hypernuclei. Based on the experiences learned, the newly approved experiment, E01-011, is under preparation with a new method in tagging the scattered electrons and a newly designed and built kaon spectrometer, that optimize the usage of electron beam for high precision hypernuclear spectroscopy. Comparing to HNSS, the hypernuclear yield and signal over background ratio will be increased by about 56 and 10 times, respectively. Most importantly, we expect to obtain an energy resolution of about 300 keV. This experimental setup will open a door for high yield, high quality, and high precision hypernuclear spectroscopic study in a wide mass range. The immediate goal of E01-011 is to study hypernuclei in the medium heavy region.

Liguang Tang

2004-10-22

205

Creating high-stability high-precision bipolar trim power supply  

SciTech Connect

Thomas Jefferson National Accelerator Facility (TJNAF) is founded by the US Department of Energy (DOE) office of science for the technology advancement and physics research in electron beam accelerator. This facility has the state of the art technology to carry out world-class cutting-edge experiments for the nucleus composition and atomic characteristics identification and exploration for the nature of the matter in the universe. A continuous wave electron beam is featured for such experiments, thus precise and stable trim power supply is required to meet such purpose. This paper demonstrates the challenges and solutions to design, assemble, fabrication and test such high-precision high-stability power supplies. This paper presents the novel design and first article test of the ±20A ±75V bipolar, 100ppm stability level current-regulated high-power trim power supplies for the beam manipulation. This special design can provide valuable documentation and reference values for future designs and special applications in particle accelerator power supply creation.

Chen, Zhe [JLAB; Merz, William A. [JLAB

2012-07-01

206

High-Precision Measurements of the Brightness Variation of Nereid  

NASA Astrophysics Data System (ADS)

Nereid, the outer satellite of Neptune, has a highly eccentric prograde orbit with a semimajor axis of larger than 200 in units of Neptune's radius, and is classified as an irregular satellite. Although the capture origin of irregular satellites has been widely accepted, several previous studies suggest that Nereid was formed in the circumplanetary disk of Neptune and ejected outward to the present location by Triton. A series of our photometric observations confirm that Nereid's rotation period, 11.5 hr, is stable and nonchaotic, as indicated by Grav, Holman, and Kavelaars (2003, ApJ, 591, L71). The optical colors of Nereid are indistinguishable from those of trans-Neptunian objects and Centaurs, especially from these objects with neutral colors. We also found the consistency of Nereid's rotation period based on the size-rotation distribution of small outer bodies. It is likely that Nereid originated as an immigrant body captured from the heliocentric orbit that was 4-5 AU away from Neptune's orbit.

Terai, Tsuyoshi; Itoh, Yoichi

2013-04-01

207

A research of a high precision multichannel data acquisition system  

NASA Astrophysics Data System (ADS)

The output signals of the focusing system in lithography are analog. To convert the analog signals into digital ones which are more flexible and stable to process, a desirable data acquisition system is required. The resolution of data acquisition, to some extent, affects the accuracy of focusing. In this article, we first compared performance between the various kinds of analog-to-digital converters (ADC) available on the market at the moment. Combined with the specific requirements (sampling frequency, converting accuracy, numbers of channels etc) and the characteristics (polarization, amplitude range etc) of the analog signals, the model of the ADC to be used as the core chip in our hardware design was determined. On this basis, we chose other chips needed in the hardware circuit that would well match with ADC, then the overall hardware design was obtained. Validation of our data acquisition system was verified through experiments and it can be demonstrated that the system can effectively realize the high resolution conversion of the multi-channel analog signals and give the accurate focusing information in lithography.

Zhong, Ling-na; Tang, Xiao-ping; Yan, Wei

2013-08-01

208

High-precision absolute distance and vibration measurement with frequency scanned interferometry  

Microsoft Academic Search

We report high-precision absolute distance and vibration measurements performed with frequency scanned interferometry using a pair of single-mode optical fibers. Absolute distance was determined by counting the interference fringes produced while scanning the laser frequency. A high-finesse Fabry-Perot interferometer was used to determine frequency changes during scanning. Two multiple-distance-measurement analysis techniques were developed to improve distance precision and to extract

Hai-Jun Yang; Jason Deibel; Sven Nyberg; Keith Riles

2005-01-01

209

Position control of linear switched reluctance motors for high-precision applications  

Microsoft Academic Search

Most advanced manufacturing processes require precise motions for material transfer, packaging, assembly, and electrical wiring. To achieve precise linear motions, most of these high-performance manufacturing machines use X-Y sliding tables with permanent-magnet rotary motors and rotary to linear couplers. Though this method is the most widely used, it has disadvantages of low accuracy, complex mechanical adjustments, high cost, and low

Wai-Chuen Gan; Norbert C. Cheung; Li Qiu

2003-01-01

210

Animal Experimentation in High Schools  

ERIC Educational Resources Information Center

|Recommends that teacher and student be provided with the broadest possible spectrum of meaningful and feasible experiments in which the comfort of the experimental animal is protected by the design of the experiment. (BR)|

Ansevin, Kystyna D.

1970-01-01

211

Ultrastable mirrors made from diamond reinforced SiC composites for high precision and power applications  

NASA Astrophysics Data System (ADS)

Diamond reinforced reaction bonded silicon carbide composites have unique properties such as very high stiffness, low density, low thermal expansion coefficient and high thermal conductivity making them attractive materials for high precision optical and structural components. However, their use in high precision equipments was limited due to significant difficulties in high tolerance machining of these super hard composites. In this present work, machineable diamond reinforced SiC composites were fabricated through forming hybrid monolithic microstructures with diamond free machineable surfaces. The resulting machineable composites were used to produce ultra-stable mirror substrates with optional internal cooling channels for high power laser optic applications.

Akbas, M. A.; Mastrobattisto, D.; Vance, W.; Jurgaitis, P.; Aghajanian, M. K.

2012-10-01

212

Application of quantum cascade lasers to high-precision atmospheric trace gas measurements  

NASA Astrophysics Data System (ADS)

We review our recent results in development of high-precision laser spectroscopic instrumentation using midinfrared quantum cascade lasers (QCLs). Some of these instruments have been directed at measurements of atmospheric trace gases where a fractional precision of 10-3 or better of ambient concentration may be required. Such high precision is needed in measurements of fluxes of stable atmospheric gases and measurements of isotopic ratios. Instruments that are based on thermoelectrically cooled midinfrared QCLs and thermoelectrically cooled detectors have been demonstrated that meet the requirements of high-precision atmospheric measurements, without the need for cryogens. We also describe the design of and results from a new dual QCL instrument with a 200-m path-length absorption cell. This instrument has demonstrated 1-s noise of 32 ppt for formaldehyde (HCHO) and 9 ppt for carbonyl sulfide (OCS).

McManus, J. Barry; Zahniser, Mark S.; Nelson, David D.; Shorter, Joanne H.; Herndon, Scott; Wood, Ezra; Wehr, Rick

2010-11-01

213

Toward the robust control of high-bandwidth high-precision flexible optical systems  

NASA Astrophysics Data System (ADS)

It is well known that control-structure-interaction (CSI) phenomena limit the stability and performance of controlled flexible structures. Most CSI research focuses on rigid body control of flexible structures with relatively low closed loop control bandwidths. This research examines the CSI phenomena associated with high bandwidth high precision control of a reaction actuator mounted to a flexible support structure. In particular, CSI using a high gain proportional integral-derivative (PID) controller is examined as it relates to certain design parameters. Rapid small angle line-of-sight repositioning and precision line-of-sight stabilization against a variety of disturbances are performed using both a single and multimode model. The single flexible mode model consists of a three-mass lightly damped translating system, referred to as the modified benchmark model. The multimode model consists of a single-axis reaction steering mirror mounted to the tip of a flexible truss-like support structure. CSI analysis of the reaction actuator control problem is performed first on the single-mode model as a function of flexible mode location, then with the multimode model as a function of inertial and elastic coupling between the reaction steering mirror and the flexible support structure. The analysis describes the CSI effects on both stability and performance of a high gain line-of-sight PID controller. This research introduces the idea of bicollocated control of a reaction actuator. It also shows that control of a reaction actuator in the classical 'collocated' sense may lead to nonminimum phase zeros in the plant model and may result in an unstable closed loop system. The critical parameters affecting both stability and performance of high gain reaction actuator controllers on flexible systems are shown to be actuator natural frequency, actuator inertia, uncoupled flexible support structure model inertia, and coupled system model reaction inertia.

Barker, Kenneth Wayne

1991-07-01

214

Atomic Hydrogen as High-Precision Field Standard for High-Field EPR  

PubMed Central

We introduce atomic hydrogen trapped in an octaisobutylsilsesquioxane nanocage (H@iBuT8) as a new molecular high-precision magnetic field standard for high-field EPR spectroscopy of organic radicals and other systems with signals around g = 2. Its solid-state EPR spectrum consists of two narrow lines separated by about 51 mT and centered at g ? 2. The isotropic g factor is 2.00294(3) and essentially temperature independent. The isotopic 1H hyperfine coupling constant is 1416.8(2) MHz below 70 K and decreases slightly with increasing temperature to 1413.7(1) MHz at room temperature. The spectrum of the standard does not overlap with those of most organic radicals, and it can be easily prepared and is stable at room temperature.

Stoll, Stefan; Ozarowski, Andrew; Britt, R. David; Angerhofer, Alexander

2010-01-01

215

Precision Crystal Calorimeters in High Energy Physics: Past, Present, and Future  

ScienceCinema

Precision crystal calorimeters traditionally play an important role in high energy physics experiments. In the last two decades, it faces a challenge to maintain its precision in a hostile radiation environment. This paper reviews the performance of crystal calorimeters constructed for high energy physics experiments and the progress achieved in understanding crystal's radiation damage as well as in developing high quality scintillating crystals for particle physics. Potential applications of new generation scintillating crystals of high density and high light yield, such as LSO and LYSO, in particle physics experiments is also discussed.

216

Machine vision for high-precision volume measurement applied to levitated containerless material processing  

Microsoft Academic Search

By combining the best practices in optical dilatometry with numerical methods, a high-speed and high-precision technique has been developed to measure the volume of levitated, containerlessly processed samples with subpixel resolution. Containerless processing provides the ability to study highly reactive materials without the possibility of contamination affecting thermophysical properties. Levitation is a common technique used to isolate a sample as

R. C. Bradshaw; D. P. Schmidt; J. R. Rogers; K. F. Kelton; R. W. Hyers

2005-01-01

217

High Precision Fast Projective Synchronization for Chaotic Systems with Unknown Parameters  

NASA Astrophysics Data System (ADS)

A high precision fast projective synchronization method for chaotic systems with unknown parameters was proposed by introducing optimal matrix. Numerical simulations indicate that the precision be improved about three orders compared with other common methods under the same condition of software and hardware. Moreover, when average error is less than 10-3, the synchronization speed is 6500 times than common methods, the iteration needs only 4 times. The unknown parameters also were identified rapidly. The theoretical analysis and proof also were given.

Nian, Fuzhong; Wang, Xingyuan; Lin, Da; Niu, Yujun

2013-08-01

218

High-precision radiocarbon dating and historical biblical archaeology in southern Jordan  

Microsoft Academic Search

Recent excavations and high-precision radiocarbon dating from the largest Iron Age (IA, ca. 1200-500 BCE) copper production center in the southern Levant demonstrate major smelting activities in the region of biblical Edom (southern Jordan) during the 10th and 9th centuries BCE. Stratified radiocarbon samples and artifacts were recorded with precise digital surveying tools linked to a geographic information system developed

Thomas E. Levy; Thomas Higham; Christopher Bronk Ramsey; Neil G. Smith; Erez Ben-Yosef; Mark Robinson; Stefan Münger; Kyle Knabb; Jürgen P. Schulze; Mohammad Najjar; Lisa Tauxe

2008-01-01

219

High-precision timing observations of the millisecond pulsar PSR 1821-24 at Nancay  

Microsoft Academic Search

High-precision timing observations of the millisecond pulsar PSR 1821-24 have been conducted on 305 individual dates at the Nancay radiotelescope at 1.4GHz between March 2 1989 and July 21 1993. The Time Of Arrival residuals after the standard fit of the pulsar parameters are characterised by a rms of 2.78mus. This dense and precise timing series has allowed the first

I. Cognard; G. Bourgois; J.-F. Lestrade; F. Biraud; D. Aubry; B. Darchy; J.-P. Drouhin

1996-01-01

220

Ultrasonic linear motor for a high precision X-Y stage  

Microsoft Academic Search

Experiments on a mechanical configuration and control system for an ultrasonic linear motor for a high precision X-Y stage were conducted, and a velocity up to 100 mm\\/s and a positioning resolution of 0.016 ?m were obtained. The motor consists of a piezoelectric drive element using multilayer piezoelectric ceramic actuators. To realize both long-distance drive and very precise positioning, the

K. Mori; T. Kumagae; H. Hirai

1989-01-01

221

High-precision measurement of the electron drift velocity in Ne CO2  

NASA Astrophysics Data System (ADS)

The baseline gas mixture which will be used in the ALICE TPC is 90% Ne and 10% CO2. The change of the drift velocity due to changes of the CO2 concentration as well as N2 addition has been studied in high-precision measurements at drift fields between 100 and 900 V/cm. Also a precise absolute measurement of the drift velocity has been made. All measurements are compared with calculations.

Wiechula, J.; Braun-Munzinger, P.; Daues, H.; Frankenfeld, U.; Garabatos, C.; Hehner, J.; Renfordt, R.; Schmidt, H. R.; Stelzer, H.; Vrani?, D.

2005-08-01

222

Construction of a Versatile High Precision Ambient Ionization Source for Direct Analysis and Imaging  

PubMed Central

The design and construction of a high precision ambient ionization source matrix-assisted laser desorption electrospray ionization (MALDESI) is described in full detail including a complete parts list. The computer controlled high precision motion control system and high repetition rate Explorer laser are demonstrated during MALDESI-FT-ICR analysis of peptides and proteins ranging from 1–17 kDa. The high stability ionization source platform described herein demonstrates both the advantages of the new MALDESI source and versatility for application to numerous desorption and ionization techniques.

Sampson, Jason S.; Hawkridge, Adam M.; Muddiman, David C.

2008-01-01

223

Use of Terrestrial Laser Scanning Technology for Long Term High Precision Deformation Monitoring  

PubMed Central

The paper presents a new methodology for high precision monitoring of deformations with a long term perspective using terrestrial laser scanning technology. In order to solve the problem of a stable reference system and to assure the high quality of possible position changes of point clouds, scanning is integrated with two complementary surveying techniques, i.e., high quality static GNSS positioning and precise tacheometry. The case study object where the proposed methodology was tested is a high pressure underground pipeline situated in an area which is geologically unstable.

Vezocnik, Rok; Ambrozic, Tomaz; Sterle, Oskar; Bilban, Gregor; Pfeifer, Norbert; Stopar, Bojan

2009-01-01

224

Machine vision for high-precision volume measurement applied to levitated containerless material processing  

SciTech Connect

By combining the best practices in optical dilatometry with numerical methods, a high-speed and high-precision technique has been developed to measure the volume of levitated, containerlessly processed samples with subpixel resolution. Containerless processing provides the ability to study highly reactive materials without the possibility of contamination affecting thermophysical properties. Levitation is a common technique used to isolate a sample as it is being processed. Noncontact optical measurement of thermophysical properties is very important as traditional measuring methods cannot be used. Modern, digitally recorded images require advanced numerical routines to recover the subpixel locations of sample edges and, in turn, produce high-precision measurements.

Bradshaw, R.C.; Schmidt, D.P.; Rogers, J.R.; Kelton, K.F.; Hyers, R.W. [Department of Mechanical and Industrial Engineering, University of Massachusetts, Amherst, Massachusetts 01003 (United States); NASA Marshall Space Flight Center, Huntsville, Alabama 35812 (United States); Department of Physics, Washington University, St. Louis, Missouri 63130 (United States); Department of Mechanical and Industrial Engineering, University of Massachusetts, Amherst, Massachusetts 01003 (United States)

2005-12-15

225

A theoretical and experimental investigation of surface roughness formation in ultra-precision diamond turning  

Microsoft Academic Search

In this paper, a model-based simulation system is presented for the analysis of surface roughness generation in ultra-precision diamond turning. The system is based on a surface roughness model which takes into account the effect of tool geometry, process parameters and relative tool-work vibration. It is evaluated through a series of cutting experiments. The results indicate that the system can

C. F Cheung; W. B Lee

2000-01-01

226

Initial Development of High Precision, High Resolution Ion Beam Spectrometer in the Near-Infrared  

NASA Astrophysics Data System (ADS)

Interest in molecular ions stretches across many fields, from combustion to astrochemistry. These ions can be difficult to study spectroscopically in the laboratory, however. Obstacles include the relatively small density of ions produced in samples compared to neutral molecules and high rotational temperatures of the ions (which lead to dilution of the energy levels). To overcome some of these challenges of molecular ion spectroscopy, we are developing a fast ion beam spectrometer system we call Sensitive, Cooled, Resolved Ion BEam Spectroscopy (SCRIBES). This setup will enable the sensitive study of a supersonically cooled ion beam, taking advantage of narrow linewidths, a mass-dependent Doppler shift for mass identification of each spectral line, and on-line mass spectrometry for beam composition studies. Presently, the spectrometer contains an ion beam source that produces ions at high rotational temperature. We have characterized the spectrometer using the near-infrared rovibronic transitions of N_2^+, optimizing the sensitivity of the instrument. Furthermore, we have used an optical frequency comb for highly accurate frequency calibration, measuring a N_2^+ transition to within an accuracy of 8 MHz. This work in the near-infrared has laid the foundation for mid-infrared and indirect THz ion beam spectroscopy of many interesting molecular ions at a high level of precision, accuracy, and resolution.

Porambo, Michael; Siller, Brian; Mills, Andrew; Perera, Manori; Kreckel, Holger; McCall, Benjamin

2012-06-01

227

Deterministic ion beam material adding technology for high-precision optical surfaces.  

PubMed

Although ion beam figuring (IBF) provides a highly deterministic method for the precision figuring of optical components, several problems still need to be addressed, such as the limited correcting capability for mid-to-high spatial frequency surface errors and low machining efficiency for pit defects on surfaces. We propose a figuring method named deterministic ion beam material adding (IBA) technology to solve those problems in IBF. The current deterministic optical figuring mechanism, which is dedicated to removing local protuberances on optical surfaces, is enriched and developed by the IBA technology. Compared with IBF, this method can realize the uniform convergence of surface errors, where the particle transferring effect generated in the IBA process can effectively correct the mid-to-high spatial frequency errors. In addition, IBA can rapidly correct the pit defects on the surface and greatly improve the machining efficiency of the figuring process. The verification experiments are accomplished on our experimental installation to validate the feasibility of the IBA method. First, a fused silica sample with a rectangular pit defect is figured by using IBA. Through two iterations within only 47.5 min, this highly steep pit is effectively corrected, and the surface error is improved from the original 24.69 nm root mean square (RMS) to the final 3.68 nm RMS. Then another experiment is carried out to demonstrate the correcting capability of IBA for mid-to-high spatial frequency surface errors, and the final results indicate that the surface accuracy and surface quality can be simultaneously improved. PMID:23435003

Liao, Wenlin; Dai, Yifan; Xie, Xuhui; Zhou, Lin

2013-02-20

228

High Precision Brillouin Zone Integration for the Magnetocrystalline Anisotropy Energy: A comparative Study.  

NASA Astrophysics Data System (ADS)

Electronic structure calculations of magnetocrystalline anisotropy energy (MAE) require the calculation of total energy differences with high precision (<= ? eV/atom). The method used to perform the Brillouin zone integration determines the overall computational effort via the number of k vectors necessary to achieve the required precision. In the tetrahedron method effects near band edges and the Fermi surface lead to an oscillatory behavior which results in an almost prohibitive large number of k vectors in the case of MAE in transition metals. Broadening methods introduce a smooth density of states and show rapid convergence, but the broadening limits the obtainable precision. For the special case of MAE a state tracking method has been used to overcome the slow convergence of the tetrahedron method. We compare the convergence properties and the precision of these methods for several test cases. Of particular interest is the dependence of results on the size of the broadening, especially cases where the broadening method breaks down.

Schneider, G.; Jansen, H. J. F.

1997-03-01

229

High-precision pepper-pot technique for a low-emittance electron beam  

NASA Astrophysics Data System (ADS)

An emittance measurement system employing a high-precision pepper-pot technique has been developed for an electron beam with low emittance, less than ? mm mrad. Since luminous spots on a scintillator are very small, each one was magnified and observed individually with high spatial resolution by scanning an optical system mounted on a precise movable platform. The beam from a high-brightness electron gun was evaluated using this system. Present address: Naruto University of Education, Narutocho, Naruto-shi, Tokushima 772, Japan.

Yamazaki, Y.; Kurihara, T.; Kobayashi, H.; Sato, I.; Asami, A.

1992-11-01

230

Experimental High Energy Neutrino Astrophysics  

SciTech Connect

Neutrinos are considered promising probes for high energy astrophysics. More than four decades after deep water Cerenkov technique was proposed to detect high energy neutrinos. Two detectors of this type are successfully taking data: BAIKAL and AMANDA. They have demonstrated the feasibility of the high energy neutrino detection and have set first constraints on TeV neutrino production astrophysical models. The quest for the construction of km3 size detectors have already started: in the South Pole, the IceCube neutrino telescope is under construction; the ANTARES, NEMO and NESTOR Collaborations are working towards the installation of a neutrino telescope in the Mediterranean Sea.

Distefano, Carla [Laboratori Nazionali del Sud, Catania (Italy)

2005-10-12

231

Magnetic Field Noise from High Permeability Magnetic Shields for Precision Measurements  

Microsoft Academic Search

High permeability magnetic shields often generate magnetic field noise that can limit the sensitivity of precision measurements. We show that calculations based on the fluctuation-dissipation theorem allow evaluation of magnetic field noise, either by current or spin fluctuations, from high permeability metals and ferrites over a broad frequency range. For example, the noise spectrum of a mu-metal shield generally exhibits

S.-K. Lee; S. J. Smullin; T. W. Kornack; M. V. Romalis

2007-01-01

232

Advanced navigation and guidance for high-precision planetary landing on Mars  

Microsoft Academic Search

Several international missions scheduled for years 2011--2013 have as objective a Mars surface sample return to Earth. In order to gather samples of high scientific quality, these missions require precise landing at preselected locations on Mars. Since the previous missions on Mars have flown unguided and highly inaccurate atmospheric entry, a new generation of landing systems must be developed. It

Jean-Francois Levesque

2006-01-01

233

Development of a low cost high precision three-layer 3D artificial compound eye.  

PubMed

Artificial compound eyes are typically designed on planar substrates due to the limits of current imaging devices and available manufacturing processes. In this study, a high precision, low cost, three-layer 3D artificial compound eye consisting of a 3D microlens array, a freeform lens array, and a field lens array was constructed to mimic an apposition compound eye on a curved substrate. The freeform microlens array was manufactured on a curved substrate to alter incident light beams and steer their respective images onto a flat image plane. The optical design was performed using ZEMAX. The optical simulation shows that the artificial compound eye can form multiple images with aberrations below 11 ?m; adequate for many imaging applications. Both the freeform lens array and the field lens array were manufactured using microinjection molding process to reduce cost. Aluminum mold inserts were diamond machined by the slow tool servo method. The performance of the compound eye was tested using a home-built optical setup. The images captured demonstrate that the proposed structures can successfully steer images from a curved surface onto a planar photoreceptor. Experimental results show that the compound eye in this research has a field of view of 87°. In addition, images formed by multiple channels were found to be evenly distributed on the flat photoreceptor. Additionally, overlapping views of the adjacent channels allow higher resolution images to be re-constructed from multiple 3D images taken simultaneously. PMID:24104115

Zhang, Hao; Li, Lei; McCray, David L; Scheiding, Sebastian; Naples, Neil J; Gebhardt, Andreas; Risse, Stefan; Eberhardt, Ramona; Tünnermann, Andreas; Yi, Allen Y

2013-09-23

234

Flux Leakage Measurements for Defect Characterization Using a High Precision 3AXIAL Gmr Magnetic Sensor  

Microsoft Academic Search

High-precision magnetic field sensors are of increasing interest in non destructive testing (NDT). In particular GMR-sensors (giant magneto resistance) are qualified because of their high sensitivity, high signal-to-noise ratio and high spatial resolution. With a GMR-gradiometer and a 3D-GMR-magnetometer we performed magnetic flux leakage measurements of artificial cracks and cracks of a depth of <=50 mum still could be dissolved

M. Pelkner; M. Blome; V. Reimund; H.-M. Thomas; M. Kreutzbruck

2011-01-01

235

SOPHIE+: First results of an octagonal-section fiber for high-precision radial velocity measurements  

NASA Astrophysics Data System (ADS)

High-precision spectrographs play a key role in exoplanet searches and Doppler asteroseismology using the radial velocity technique. The 1 m s-1level of precision requires very high stability and uniformity of the illumination of the spectrograph. In fiber-fed spectrographs such as SOPHIE, the fiber-link scrambling properties are one of the main conditions for high precision. To significantly improve the radial velocity precision of the SOPHIE spectrograph, which was limited to 5-6 m s-1, we implemented a piece of octagonal-section fiber in the fiber link. We present here the scientific validation of the upgrade of this instrument, demonstrating a real improvement. The upgraded instrument, renamed SOPHIE+, reaches radial velocity precision in the range of 1-2 m s-1. It is now fully efficient for the detection of low-mass exoplanets down to 5-10 M? and for the identification of acoustic modes down to a few tens of cm s-1.

Bouchy, F.; Díaz, R. F.; Hébrard, G.; Arnold, L.; Boisse, I.; Delfosse, X.; Perruchot, S.; Santerne, A.

2013-01-01

236

Basic design of the High Precision Thermostat (HPT) of the D1 mission  

NASA Astrophysics Data System (ADS)

The principal design criteria and main features of the High Precision Thermostat for the D1 mission and the modular, mechanical, and electrical structure of the experiment facility are outlined. The design of the 4 stage scanning ratio calorimeter used for measuring the isochore specific heat capacity of SF6 at its critical point is described. Characteristic performance data as well as the characteristics of the loops for high precision temperature measurement and control (down to less than 1 mK) for the calorimeter's stages are presented.

Kemmerle, K.

1987-02-01

237

A New High Precision Low Offset Dynamic Comparator for High Resolution High Speed ADCs  

Microsoft Academic Search

A new low offset dynamic comparator for high resolution high speed analog-to-digital application has been designed. Inputs are reconfigured from the typical differential pair comparator such that near equal current distribution in the input transistors can be achieved for a meta-stable point of the comparator. Restricted signal swing clock for the tail current is also used to ensure constant currents

Vipul Katyal; Randall L. Geiger; Degang J. Chen

2006-01-01

238

19 Years of high precision timing of the millisecond pulsar J1713+0747  

NASA Astrophysics Data System (ADS)

We report the analysis of a 19-year span of timing data on PSR J1713+0747 taken by the Arecibo and Green Bank telescopes. PSR J1713+0747 is one of the best high-timing-precision pulsars monitored by the NANOGrav project for the purpose of detecting gravitational waves. The timing precision of this pulsar can be regarded as the benchmark of NANOGrav timing instruments. We show the precision improvement achieved by multi-generation instruments including the Green Bank Ultimate Pulsar Processing Instrument (GUPPI) and its counterpart in Arecibo. The new timing solution we found improves the measurement of the pulsars mass, its orbital and geometric parameters, sets new limits on alternative gravitational theories, and may provide a high-quality single pulsar gravitational wave upper limit.

Zhu, Weiwei

2013-03-01

239

Determination of standard sample purity using the high-precision 1H-NMR process.  

PubMed

This paper discusses the technique for high-precision quantification using (1)H-NMR to determine the purity of analytical standard samples. The procedure described is based on the use of internal reference samples in an (1)H NMR experiment in our laboratories. The sample preparation and all relevant NMR parameters were optimized for minimum uncertainty. The validation of accuracy and precision was performed by comparing different certified reference materials. It was shown that the high-precision measurement is applicable even for relatively small sample amounts down to 2.5 mg. The relative combined uncertainty of measurement was found to be 0.15%. Two different approaches for uncertainty calculation were compared; a complete uncertainty budget was calculated. PMID:22327969

Schoenberger, Torsten

2012-02-12

240

Conditions and methods of high-precision measurement of blood glucose concentration using mid-IR ATR spectroscopy  

NASA Astrophysics Data System (ADS)

This paper involves conditions and methods of high precision measurement of blood glucose concentration using Mid-IR ATR spectroscopy: (1) Comparing the spectra of saline solution, plasma, and whole blood to which adding glucose respectively, we find that in these three backgrounds with different complexity, the absorption peaks of glucose are at the same wavelengths in the band of 1200 to 900 cm-1. (2) Analyzing experimental results of concentration gradient built by adding glucose to a series of plasma, we obtained a high correlation (greater than 0.98) between glucose concentration and absorbance in the band of 1200 to 900 cm-1, it provides us the feasibility of building calibration model of glucose concentration in this specific band. (3) In the process of building calibration model for glucose concentration of 40 whole blood samples (blood glucose concentration varied from 73 to 167 mg/dL, mean was 94.46 mg/dL, standard error was 17.68 mg/dL) by utilizing PLS method optimized with full cross validation, we applied genetic algorithms to the selection of optical subsets of wavelengths, the number of wavelengths for calibration was decreased to 14 and the precision of the model was improved considerably, RMSEP was 10.56 mg/dL. This proves that high precision measurement of blood glucose concentration can be achieved in narrow-band width (1200-900cm-1) when few wavelengths are selected.

Qin, Jianwei; Zhou, Dingwen; Zhang, Lu; Lei, Zhenlin; Xu, Kexin

2002-09-01

241

High precision position control of voice coil motor based on single neuron PID  

NASA Astrophysics Data System (ADS)

Voice coil motor(VCM) is widely used in high-speed and high-precision positioning control system in recent years. However, there are system uncertainty, nonlinear, modeling error, and external disturbances in the high-precision positioning control system, traditional PID control method is difficult to achieve precise positioning control. In this paper, a new position control strategy with a single neuron controller which has the capability of self-studying and self-adapting composed with PID controller is put forward, and the feedforward compensator is added to improve the dynamic response of the system in the position loop. Moreover, the disturbance observer is designed to suppress model parameter uncertainty and external disturbance signal in the current loop. In addition, the problem of high precision position control of VCM under the influence of significant disturbances is addressed, which including the gas-lubricated damping, the spring, the back EMF and ripple forces, on the basis, the mathematical model of VCM is established accurately. The simulation results show that this kind of controller can improve the dynamic characteristic and strengthen the robustness of the system, and the current loop with disturbance observer can also restrain disturbance and high frequency.

Li, Liyi; Chen, Qiming; Tan, Guangjun; Zhu, He

2013-01-01

242

Design approach to a high-precision reflectometer for component study evaluation  

NASA Astrophysics Data System (ADS)

High-power lasers require beam directing optics with high damage thresholds. To achieve this, coatings with very high reflectivity and low absorption are being developed by many investigators. This paper describes a reflectometer for measuring these high reflectances to a very high precision. Parameters investigated for this design are source stability, detector limitations, data collection schemes, and the basic optical configuration. The most promising optical configurations investigated include a single-bounce system and a goniometric type double-bounce system. Data collection was best accomplished using a noise-eliminating sample and hold system in conjunction with a gain compensated, AC coupled amplifier referenced to a duplicate system sampling the source output. Conventional lock-in and differential amplifiers were not found acceptable for the high precision sought.

Gokay, C.; Harding, K.; Loomis, J.; Marcheski, J.

1981-01-01

243

Experimental approaches for addressing fundamental biological questions in living, functioning cells with single molecule precision  

PubMed Central

In recent years, single molecule experimentation has allowed researchers to observe biological processes at the sensitivity level of single molecules in actual functioning, living cells, thereby allowing us to observe the molecular basis of the key mechanistic processes in question in a very direct way, rather than inferring these from ensemble average data gained from traditional molecular and biochemical techniques. In this short review, we demonstrate the impact that the application of single molecule bioscience experimentation has had on our understanding of various cellular systems and processes, and the potential that this approach has for the future to really address very challenging and fundamental questions in the life sciences.

Lenn, Tchern; Leake, Mark C.

2012-01-01

244

Development of material irradiation rig with precision temperature control in experimental fast reactor JOYO  

Microsoft Academic Search

In the experimental fast reactor JOYO, an on-line instrumented material irradiation rig has been developed to acquire various irradiation data. Material Testing Rig with Temperature Control (MARICO) is capable of collecting creep rupture strength data for fast reactor fuel cladding materials. The specimen temperature in the MARICO-1 rig is controlled with an accuracy of ±4°C by the use of a

H. Kataoka; T Yasu; H Takatsudo; S Miyakawa

1998-01-01

245

High-precision reflectometry of multilayer coatings for extreme ultraviolet lithography  

Microsoft Academic Search

Synchrotron-based reflectometry is an important technique for the precise determination of optical properties of reflective multilayer coatings for Extreme Ultraviolet Lithography (EUVL). Multilayer coatings enable normal incidence reflectances of more than 65% in the wavelength range between 11 and 15 nm. In order to achieve high resolution and throughput of EUVL systems, stringent requirements not only apply to their mechanical

Marco Wedowski; James H. Underwood; Eric M. Gullikson; Sasa Bajt; James A. Folta; Patrick A. Kearney; Claude Montcalm; Eberhard A. Spiller

2000-01-01

246

High-precision reflectometry of multilayer coatings for extreme ultraviolet lithography  

Microsoft Academic Search

Synchrotron-based reflectometry is an important technique for the precise determination of optical properties of reflective multilayer coatings for Extreme Ultraviolet Lithography (EUVL). Multilayer coatings enable normal incidence reflectances of more than 65% in the wavelength range between 11 and 15 nm. In order to achieve high resolution and throughput of EUVL systems, stringent requirements not only apply to their mechanical

M Wedowski; J H Underwood; E M Gullikson; S Bajt; J A Folta; P A Kearney; C Montcalm; E Spiller

1999-01-01

247

High precision arithmetic units for fine-grain massively parallel computing  

Microsoft Academic Search

In this paper we deal with new high precision arithmetic units (AUs). These AUs are specialized in the computation of one arithmetic operation (division, addition, etc.), but when hundreds of them are interconnected by a reconfigurable network, a parallel architecture that uses massive digit-level pipelining between floating-point arithmetic units (allowing fast computation of scientific jobs) becomes interesting. In this paper

M. Fiallos-Aguilar

1994-01-01

248

A Method for High Precision Enlargement of Pictures taken by Cellular Phone on Personal Computer  

Microsoft Academic Search

In this paper, we propose a method to enlarge and display images of picture with high precision and scal- ability taken by cellular phone on personal computer without producing jaggy noises. One of the major problems we face in image en- largement is the amplification of the jaggy edges. To deal with this problem, we first detect the edges, and

Yasuhiro OHMIYA; Kazuki KATAGISHI; Paul W. H. Kwan; Kazuo TORAICHI; Atsushi MATSUMURA; Ryoichi KAWADA; Atsushi KOIKE; Hitomi MURAKAMI

249

Towards High-Precision Ground-Based Astrometry: Differential Delay Lines for PRIMA@VLTI  

Microsoft Academic Search

Deriving unambiguously the orbital parameters and masses of extrasolar planets requires at least 2-dimensional information on either the positions or motions of the planet directly (currently out of reach) or, indirectly, of the host star. The latter can be done with high-precision astrometry at the 10 microarcsec level. To achieve this goal, a consortium with partners from Germany, the Netherlands,

R. Launhardt; Th. Henning; D. Queloz; A. Quirrenbach; E. J. Bakker; H. Baumeister; P. Bizenberger; H. Bleuler; R. Dändliker; F. Delplancke; F. Derie; M. Fleury; A. Glindemann; D. Gillet; H. Hanenburg; W. Jaffe; J. A. de Jong; R. Köhler; C. Maire; R. J. Mathar; P. Müllhaupt; K. Murakawa; F. Pepe; R. S. Le Poole; J. Pragt; S. Reffert; L. Sache; D. Ségransan; J. Setiawan; D. Sosnowska; R. N. Tubbs; L. Venema; K. Wagner; L. Weber; R. Wüthrich

2005-01-01

250

High Precision Measurement of Tools An Integrated Approach Based on HALCON  

Microsoft Academic Search

A methodology for proving the accuracy of a system for high precision measurement of cutting tools is described. The tools are backlit by infrared illumination. Images are acquired by telecentric lenses and standard cameras and framegrabbers. The outer boundary of the tools is extracted by subpixel edge detection and is then approximated by lines and circular arcs. All processing is

Gerhard Blahusch; Wolfgang Eckstein; Carsten Steger; Stefan Lanser

251

Research progress on metrological uses of high precision millisecond pulsar timing data  

Microsoft Academic Search

We reviewed the research progress on time keeping meterology using millisecond pulsars. Millisecond pulsars exhibit a very stable spinning period, so that their rotational phase may be used as a time reference, named pular time (PT). The analyses of high precision timing data for two millisecond pulsars showed that the long-term stability of TA-PT may be compared to atomic time

Ting-Gao Yang; Lian-De Pan; Guan-Gren Ni; Xi-Zheng Ke

2002-01-01

252

High-precision control of a maglev linear actuator with nanopositioning capability  

Microsoft Academic Search

Presents high-precision control of a magnetically levitated (maglev) linear actuator with novel geometric configuration. The linear actuator is used as a unit actuator in the development of a maglev instrument with six-axis nanopositioning capability. The novel configuration in this design concept leads to a lightweight and compact size. The objective of development of this maglev linear actuator is to verify

Won-jong Kim; Himanshu Maheshwari

2002-01-01

253

Numerical Tests of High-Precision Multiple-Scattering Band Theory.  

National Technical Information Service (NTIS)

Calculations done on the empty lattice test the convergence properties of high precision nonmuffin tin band theories based on multiple scattering. The results at l max = 6 in the scattered wave show that two methods of this type are still strongly converg...

R. G. Brown M. Ciftan

1986-01-01

254

Development of High-Precision Monitoring Technology for Green House Gases  

Microsoft Academic Search

High-precision monitoring technology has been developed to monitor the production of greenhouse gases (CO2, CH4, and N2O) in the vicinity of industrial plants and in the general atmosphere. This technology is based on tunable diode laser absorption spectroscopy, and, in combination with proprietary wavelength modulation and laser wavelength stabilization technologies, offers superior sensitivity, responsiveness, and stability.

MASAKI IIJIMA; KENJI MUTA; TOMOYUKI KIKUGAWA; MASAZUMI TANOURA; KO NAKAYA

255

Study on intelligent analysis and simulation of high precision sensor data  

Microsoft Academic Search

With the informationization of mechanical devices, high precision sensors have been widely applied to all kinds of mechanical devices for the information gathering. However, as the sensors are produced by various research centers and manufacturers, there is a considerable difficulty in examining and identifying the sensors. In this article, A new intelligent analysis model based on BP+GA algorithms is presented

Xue Qing; Cao Bo-wei; Huang Yi-Ping; Yu Ping-gang; Wei Yang

2010-01-01

256

Technological complexes for the shaping of large high-precision aspherical surfaces.  

NASA Astrophysics Data System (ADS)

A concept is proposed for the structure of technological complexes for the shaping of large high-precision aspherical surfaces. The makeup of such technological complexes is considered. Optical lathes that have been developed and are now in their final stage of fabrication are indicated for the shaping of large optical surfaces up to 4000 mm in diameter.

Bubis, I. Ya.; Esin, D. R.

1990-11-01

257

A high-precision camera operation parameter measurement system and its application to image motion inferring  

Microsoft Academic Search

Information about camera operations such as zoom, focus, pan, tilt and dollying is significant not only for efficient video coding, but also for content-based video representation. In this paper we describe a high-precision camera operation parameter measurement system and apply it to image motion inferring. First, we outline the implemented system which is designed to provide camera operation parameters with

Wentao Zheng; Yoshiaki Shishikui; Yasuaki Kanatsugu; Yutaka Tanaka; Ichiro Yuyama

2001-01-01

258

Adaptive control of the grinding of high-precision bearing rings  

Microsoft Academic Search

722 Stable grinding of high-precision (in particular, airplane) bearings is ensured by increasing the number of grinding processes and reducing the machining stress. In that case, more than half of the machining time may be taken up by idling or transient conditions, when some of the kinetic energy of the blank is consumed in elastic deformation of the components in

M. P. Vasin; V. V. Gorbunov; A. A. Ignat’ev

2007-01-01

259

High-Precision Mg Isotopic Composition of Type B1 and B2 CAI Melilite  

NASA Astrophysics Data System (ADS)

The Mg isotopic composition as a function of the åkermanite composition has been measured with high precision with a Cameca IMS-1280 in two Type B CAIs. Matrix effects in the measurements were carefully documented and corrected based on measurements made

Richter, F. M.; Kita, N. T.; Mendybaev, R. A.; Davis, A. M.; Valley, J. W.

2007-03-01

260

High Sensitive Precise 3D Accelerometer for Solar System Exploration with Unmanned Spacecrafts  

Microsoft Academic Search

Solutions of several space and geophysical tasks require creating high sensitive precise accelerometers with sensitivity in order of 10 -13 g. These several tasks are following: inertial navigation of the Earth and Space; gravimetry nearby the Earth and into Space; geology; geophysics; seismology etc. Accelerometers (gravimeters and gradientmeters) with required sensitivity are not available now. The best accelerometers in the

Y. V. Savenko; P. O. Demyanenko; Y. F. Zinkovskiy

2004-01-01

261

Development of high precision and multifunctional timing system using integrated GPS\\/BD receiver  

Microsoft Academic Search

A highly precise and multifunctional timing system using the self development integrated GPS\\/BD time receiver is presented in this paper. The authors firstly designed an integrated GPS\\/BD (compass or Beidou navigation system of China) time receiver for time and frequency synchronization in a local network, and describing the main issues and the solution of the receiver implement in detail, and

Li Gun; Wu Fu-ping; Wei Jing-fa; Huang Xian-he

2008-01-01

262

Development and Utilization of High Precision Digital Elevation Data taken by Airborne Laser Scanner  

NASA Astrophysics Data System (ADS)

Disasters caused by heavy rain in urban areas bring a damage such as chaos in the road and railway transport systems, power failure, breakdown of the telephone system and submersion of built up areas, subways and underground shopping arcades, etc. It is important to obtain high precision elevation data which shows the detailed landform because a slight height difference affects damages by flood very considerably. Therefore, The Geographical Survey Institute (GSI) is preparing 5m grid digital terrain model (DTM) based on precise ground elevation data taken by using airborne laser scanner. This paper describes the process and an example of the use of a 5m grid digital data set.

Akutsu, Osamu; Ohta, Masataka; Isobe, Tamio; Ando, Hisamitsu, Noguchi, Takahiro; Shimizu, Masayuki

2005-03-01

263

High precision measurements of the diamond Hugoniot in and above the melt region  

SciTech Connect

High precision laser-driven shock wave measurements of the diamond principal Hugoniot have been made at pressures between 6 and 19 Mbar. Shock velocities were determined with 0.3-1.1% precision using a velocity interferometer. Impedance matching analysis, incorporating systematic errors in the equation-of-state of the quartz standard, was used to determine the Hugoniot with 1.2-2.7% precision in density. The results are in good agreement with published ab initio calculations which predict a small negative melt slope along the Hugoniot, but disagree with previous laser-driven shock wave experiments which had observed a large density increase in the melt region. In the extensive solid-liquid coexistence regime between 6 and 10 Mbar these measurements indicate that the mixed phase may be slightly more dense than would be expected from a simple interpolation between liquid and solid Hugoniots.

Hicks, D; Boehly, T; Celliers, P; Bradley, D; Eggert, J; McWilliams, R S; Collins, G

2008-08-05

264

Precision freehand sculpting for unicondylar knee replacement: design and experimental validation.  

PubMed

Precision freehand sculpting (PFS), is a hand-held semi-active robotic technology for bone shaping that works within the surgical navigation framework. PFS can alternate between two control modes - one based on control of exposure of the cutting bur and another based on the control of the speed of the cutting bur. In this study we evaluate the performance of PFS in preparing the femoral bone surface for unicondylar knee replacement (UKR). The experiment is designed to prepare a synthetic bone for UKR. The implant was a modified commercial design that allows accurate measurement of the implant position after it is placed on the prepared bone surface. The distal and anterior-distal facets were cut with a 5 mm cylindrical bur using exposure control. The posterior facet and the post holes were cut using a 6-mm spherical bur using speed control. Three users cut five specimens each. The performance was evaluated in terms of the implant fit and the performance time. The average cut times for the first two cuts combined were 4:35 min, and for the posterior cut 3:26 min. The average distance from the planned implant position was 0.54 mm (SD 0.23 mm) and the average angular difference was 1.08° (SD 0.53°). PMID:22868782

Jaramaz, Branislav; Nikou, Constantinos

2012-02-23

265

Search for resonant enhancement of neutrinoless double-electron capture by high-precision Penning-trap mass spectrometry  

NASA Astrophysics Data System (ADS)

The search for neutrinoless double-electron capture can be a good alternative to the neutrinoless double-beta-decay experiments in shedding light on such aspects of neutrino physics as the neutrino type, non-conservation of the total lepton charge and magnitude of the effective Majorana neutrino mass. The probability of neutrinoless double-electron capture can be resonantly enhanced by some orders of magnitude. Although the phenomenon of the resonant enhancement was predicted some decades ago, the search for resonantly enhanced neutrinoless double-electron-capture transitions was hampered by a lack of precise experimental values of the atomic mass differences of the transition initial and final states. Only recent progress in high-precision Penning-trap mass spectrometry has finally provided suitable means for a determination of atomic masses with a sufficient precision and thus given rise to the experimental campaign for a search for resonantly enhanced transitions. In this article, after an introduction to the theory of neutrinoless double-electron capture and the Penning-trap technique, a review is given on the results of systematic very precise direct Penning-trap measurements of the atomic mass differences of the nuclides which can undergo double-electron capture. The mass differences of 14 nuclear pairs have already been determined with a typical uncertainty of tens to a few hundreds of eV. Partial or even full resonant enhancement of the neutrinoless double-electron-capture probability has been discovered for 152Gd and 156Dy. In 156Dy a multiple resonance phenomenon has been revealed. For some transitions the half-lives have been estimated (152Gd, 164Er, 180W, 156Dy).

Eliseev, S. A.; Novikov, Yu N.; Blaum, K.

2012-12-01

266

Precise and cheap experimental setup for fast measurements of piezoelectric properties of crystals  

NASA Astrophysics Data System (ADS)

A series impedance method [Mason and Fair, Proc. IRE, 464 (1942); IEEE Standard on Piezoelectricity ANSI/IEEE Std 176-1987 (New York: The Institute of Electrical and Electronics Engeneers, 1987)] is the most popular way for investigation of piezoelectric properties of crystals. The AC voltage generated by a vibrating crystal achieves its maximum if a frequency of an exciting signal applied to the sample is equal to a resonance frequency of the sample. In this article a very simple experimental setup for piezoelectric measurements was described. Usually measurements of resonance frequencies are made at a constant temperature, which makes an experiment long-lasting. The experimental setup described below allows performance of the experiment in slow-change temperature regime.

Wiesner, M.

2004-11-01

267

An experimental multi-band precision fertilizer applicator for a potato planter  

Microsoft Academic Search

Experimental dry-fertilizer applicators presently used in potato nutritional investigations lack versatility. Belt-type applicators that meter out salts in bands of one fixed horizon at planting are most widely used (3, 4). When the effects of levels of phosphorus with and without micronutrients are being studied (5), contamination may occur by carry-over from plot to plot through belt and delivery tube

B. J. Hoyle; Herman Timm; E. R. Kucera

1967-01-01

268

Continuous online field deployable high precision and high resolution water isotope analysis from ice cores  

NASA Astrophysics Data System (ADS)

One of the most important features of ice cores as climate and atmospheric paleoarchives is their potential for high temporal resolution. The measurement of chemical impurities in ice cores that fully exploits this high resolution has become standard with the advent of Continuous Flow Analysis (CFA) from continuously melted ice core segments, often performed in the field. Meanwhile, the measurement of water stable isotopic composition (deuterium and oxygen-18) continues, for the most part, to be performed offline via discrete sampling with traditional mass spectroscopy. These offline procedures are time consuming, expensive, and do not fully exploit the temporal resolution available in the ice core. Here we describe a new method and the first results for the determination of water isotopic content measured from a continuous melted rod with a commercially available near-infrared cavity ring down spectrometer (CRDS; http://www.picarro.com/) coupled to a CFA system both in the field on the Greenland ice sheet and in the laboratory. For the measurement of water isotopes a carefully controlled fraction of the CFA melt stream is evaporated directly into the laser cavity for simultaneous analysis of both deuterium and oxygen-18 content. The details of the system have been tested with a deployment to the North Greenland Eemian Ice Drilling (NEEM) coupled to the University of Bern CFA system and in the laboratory with NGRIP ice coupled to the University of Copenhagen CFA system. The results show that the system already produces the highest interpretable resolution records that are comparable or somewhat less precise than traditional mass spectroscopy discrete sample methods. The enormous potential of the system is being realized in the density and resolution of the produced records in connection with other highly resolved series (e.g. chemical impurities), and also in the efficiency by which the records can be produced. Among other things, time series from this type of analysis will benefit ice core dating via layer counting of deconvoluted isotopic series. High resolution paleo-temperature reconstructions based on the calculation of the differential diffusion rates of the two heavy isotopologues of water vapor in firn, via the study of their spectral properties, can also benefit from the enhanced resolution of the measured time series.

Gkinis, Vasileios; Popp, Trevor; Johnsen, Sigfus; Blunier, Thomas; Stowasser, Christopher; Kettner, Ernesto

2010-05-01

269

Study on control structure analysis and optimization of high-precision measurement platform for optical aspheric surface  

Microsoft Academic Search

Taking high generality and efficiency into account, this paper presents a measurement and control means based on high-precision measurement platform including high-precision linear motors, contact and non-contact measurement sensor of 0.1um resolution and a new developed measuring software. This platform aims to achieve high-precision measurement for all kinds of optical aspheric workpieces for detection accuracy of 2um\\/200*200mm. In this paper,

Xiaolong Ke; Yinbiao Guo; Zhengzhong Wang; Jianchun Liu

2009-01-01

270

Steps and bumps: precision extraction of discrete states of molecular machines using physically-based, high-throughput time series analysis  

Microsoft Academic Search

We report new statistical time-series analysis tools providing significant improvements in the rapid, precision extraction of discrete state dynamics from large databases of experimental observations of molecular machines. By building physical knowledge and statistical innovations into analysis tools, we demonstrate new techniques for recovering discrete state transitions buried in highly correlated molecular noise. We demonstrate the effectiveness of our approach

Max A. Little; Bradley C. Steel; Fan Bai; Yoshiyuki Sowa; Thomas Bilyard; David M. Mueller; Richard M. Berry; Nick S. Jones

2010-01-01

271

Integrated hybrid vibration isolator with feedforward compensation for fast high-precision positioning X/Y tables  

NASA Astrophysics Data System (ADS)

The design, realization and control technologies of a high-performance hybrid microvibration isolator for ultra-high-precision high-speed moving X/Y tables are presented in this paper—the novel isolator with integrated passive-active high level of damping. The passive damping was implemented using air-springs in both vertical and horizontal directions, with parallel linear motors in two directions to realize the active damping and the positioning functions. It is an actual hybrid isolation system because its air-spring can also be controlled through the pneumatic loop. The isolation servo system also has fast positioning capability via the feedforward compensation for the moving tables. Compared with the conventional filtered reference type control algorithms that rely on the assumption for the adaptive filter and the controlled system, in which the disturbance is estimated from the residual signal, the feedforward compensation here shows high effectiveness of vibration isolation and high-precision positioning performance for its platform. The performance of feedforward compensation has been enhanced via an efficient state estimation adaptive algorithm, the fast Kalman filter. Finally, experimental demonstration has been shown for the prototype system and the results have verified the effectiveness of the proposed isolator system design and the adaptive control algorithm for substantially enhanced damping of the platform system with the moving X/Y tables.

Yan, T. H.; Pu, H. Y.; Chen, X. D.; Li, Q.; Xu, C.

2010-06-01

272

Development of the Portable Synchrotron MIRRORCLE-CV for High Precision Non-Destructive Testing  

SciTech Connect

We started the development of the portable synchrotron MIRRORCLE-CV series, which provides a high quality x-ray beam for high precision non-destructive testing (NDT). Computer simulations for the magnetic field design and electron dynamics reveal that the outer diameter of the synchrotron magnet can be as small as 30 cm. This synchrotron size approaches that of a conventional x-ray tube.

Hasegawa, Daisuke; Toyosugi, Norio; Noh, Young Deok; Yamada, Takanori; Morita, Masaki; Mantey, Edward; Masaoka, Sei [Photon Production Laboratory, Ltd., 4-2-1 (808) Takagai-cho Minami, Ohmihachiman-city 523-0898, Shiga (Japan); Yamada, Hironari [Synchrotron Light Life Science Center, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu-city 525-8577, Shiga (Japan)

2007-01-19

273

Nano-motion stage for high speed and precision positioning on an X-Y plane  

Microsoft Academic Search

Precision positioning technology with high speed on an X-Y plane requires to a manufacturing inspection for semiconductor and flat display areas, and so on. The authors proposed a new actuator called ldquoNano-Motion Actuator (NMA)rdquo for track following on a spin-stand that evaluated magnetic heads and media for high density magnetic recording. We applied technologies of the NMA to a new

S. Mori; Y. Sato; A. Sakurada; A. Naganawa; Y. Shibuya; G. Obinata

2009-01-01

274

High precision gamma-ray spectrometer PGS for Russian interplanetary mission to Mars  

Microsoft Academic Search

The high precision gamma-ray spectrometer (PGS) is scheduled to be launched on the Russian MARS mission in 1996, and to go into an elliptical polar orbit around Mars. The PGS consists of two high-purity germanium detectors, associated electronics, and a passive cooler and will be deployed from one of the solar panels. The PGS will measure nuclear gamma-ray emissions from

I. G. Mitrofanov; D. S. Anfimov; A. M. Chernenko; V. Sh. Dolidze; V. I. Kostenko; O. E. Isupov; A. S. Pozanenko; A. K. Ton'shev; D. A. Ushakov; G. F. Auchampaugh; M. Cafferty; D. M. Drake; E. E. Fenimore; R. W. Klebesadel; J. L. Longmire; C. E. Moss; R. C. Reedy

1996-01-01

275

High-precision optical systems with inexpensive hardware: a unified alignment and structural design approach  

NASA Astrophysics Data System (ADS)

High-precision opto-mechanical structures have historically been plagued by high costs for both hardware and the associated alignment and assembly process. This problem is especially true for space applications where only a few production units are produced. A methodology for optical alignment and optical structure design is presented which shifts the mechanism of maintaining precision from tightly toleranced, machined flight hardware to reusable, modular tooling. Using the proposed methodology, optical alignment error sources are reduced by the direct alignment of optics through their surface retroreflections (pips) as seen through a theodolite. Optical alignment adjustments are actualized through motorized, sub-micron precision actuators in 5 degrees of freedom. Optical structure hardware costs are reduced through the use of simple shapes (tubes, plates) and repeated components. This approach produces significantly cheaper hardware and more efficient assembly without sacrificing alignment precision or optical structure stability. The design, alignment plan and assembly of a 4" aperture, carbon fiber composite, Schmidt-Cassegrain concept telescope is presented.

Winrow, Edward G.; Chavez, Victor H.

2011-09-01

276

High precision mobile location framework and its service based on virtual reference station of GPS  

NASA Astrophysics Data System (ADS)

The wireless communication technology and space technology are synchronously developed in recent years, which bring up the development of location based service (LBS). At present, many location technology methods were developed. However, all these methods can only provide a relative poor location precision and depend on high cost. The technology of Virtual Reference Station (VRS) of GPS is then involved in this paper. One of the objective in this paper is aim to give the LBS position structure to improve the mobile location position when a mobile position instrument is connected with VRS network. The cheaper GPS built-in Personal Designer Aid (PDA) is then used to achieve a higher precision by using RTCM data from existing VRS network. In order to obtain a high precision position when using the low-cost GPS receiver as a rover, the infrusture of the mobile differential correction system is then put forward. According to network transportation of RTCM via internet protocol (NTRIP), the message is communicated through wireless network, such as GPRS, CDMA and so on. The rough coordinate information is sent to VRS control center continuously, and then the VRS correction information is replied to rover in the data format of RTCM3.1. So the position will be updated based on mathematic solution after the decoding of RTCM3.1 data. The thought of LBS position can improve the precision, and can speed the LBS.

Liu, Chun; Sun, Liangyu; Yao, Lianbi

2008-11-01

277

Charge breeding rare isotopes for high precision mass measurements: challenges and opportunities  

NASA Astrophysics Data System (ADS)

Ion charge breeding for Penning-trap mass spectrometry has been established as providing a precision increase that scales linearly with the charge state of the ion. Fast and efficient charge breeding is a precondition for the application of this approach to rare isotopes. However, in view of low yields and short half-lives the precision boost is partly compromised by unavoidable ion losses inherent to the charge breeding process. The mass spectrometer TRIUMFs ion trap for atomic and nuclear science is pioneering this field by coupling a Penning trap and an electron beam ion trap to the rare-isotope beam facility ISAC at TRIUMF. Here we present simulations that calculate and maximize the effective precision gain of time-of-flight ion-cyclotron-resonance measurements with highly charged ions of short-lived nuclides. In addition we compare the characteristics of measurements with singly and highly charged ions, and we summarize recent results that explored benefits of charge breeding that go beyond the precision increase.

Simon, M. C.; Macdonald, T. D.; Bale, J. C.; Chowdhury, U.; Eberhardt, B.; Eibach, M.; Gallant, A. T.; Jang, F.; Lennarz, A.; Luichtl, M.; Ma, T.; Robertson, D.; Simon, V. V.; Andreoiu, C.; Brodeur, M.; Brunner, T.; Chaudhuri, A.; Crespo López-Urrutia, J. R.; Delheij, P.; Ettenauer, S.; Frekers, D.; Grossheim, A.; Gwinner, G.; Kwiatkowski, A. A.; Lapierre, A.; Mané, E.; Pearson, M. R.; Ringle, R.; Schultz, B. E.; Dilling, J.

2013-09-01

278

A New High-precision Correction Method of Temperature Distribution in Model Stellar Atmospheres  

NASA Astrophysics Data System (ADS)

The main features of the temperature correction methods, suggested and used in modeling of plane-parallel stellar atmospheres, are discussed. The main features of the new method are described. Derivation of the formulae for a version of the Unsöld-Lucy method, used by us in the SMART (Stellar Model Atmospheres and Radiative Transport) software for modeling stellar atmospheres, is presented. The method is based on a correction of the model temperature distribution based on minimizing differences of flux from its accepted constant value and on the requirement of the lack of its gradient, meaning that local source and sink terms of radiation must be equal. The final relative flux constancy obtainable by the method with the SMART code turned out to have the precision of the order of 0.5 %. Some of the rapidly converging iteration steps can be useful before starting the high-precision model correction. The corrections of both the flux value and of its gradient, like in Unsöld-Lucy method, are unavoidably needed to obtain high-precision flux constancy. A new temperature correction method to obtain high-precision flux constancy for plane-parallel LTE model stellar atmospheres is proposed and studied. The non-linear optimization is carried out by the least squares, in which the Levenberg-Marquardt correction method and thereafter additional correction by the Broyden iteration loop were applied. Small finite differences of temperature (? T/T=10-3) are used in the computations. A single Jacobian step appears to be mostly sufficient to get flux constancy of the order 10-2 %. The dual numbers and their generalization -- the dual complex numbers (the duplex numbers) -- enable automatically to get the derivatives in the nilpotent part of the dual numbers. A version of the SMART software is in the stage of refactorization to dual and duplex numbers, what enables to get rid of the finite differences, as an additional source of lowering precision of the computed results.

Sapar, A.; Poolamäe, R.; Sapar, L.

279

High-Precision Imaging Photometers for the Transient Exoplanet Survey Satellite  

NASA Astrophysics Data System (ADS)

The Transient Exoplanet Survey Satellite (TESS) is designed to search for transiting exoplanet systems around all stars with V < 12. The TESS payload consists of a bank of six identical, wide-field, high-precision imaging photometers. When deployed on the highly-stable TESS satellite platform, these photometers can perform <200 ppm photometry for V=8 stars (? ppm for V=6 stars) in a 10-minute observation. We describe the components of the TESS imaging photometers: the custom, wide-field optics; the large-area CCD arrays; and the low-power, high precision CCD electronics. Support for TESS has been provided by NASA, the Kavli Foundation, Google, and the Smithsonian Institution.

Kraft Vanderspek, Roland; Ricker, G. R.; Latham, D. W.; Ennico, K.; Bakos, G.; Brown, T. M.; Burgasser, A. J.; Charbonneau, D.; Clampin, M.; Deming, L.; Doty, J. P.; Dunham, E. W.; Elliot, J. L.; Holman, M. J.; Ida, S.; Jenkins, J. M.; Jernigan, J. G.; Kawai, N.; Laughlin, G. P.; Lissauer, J. J.; Martel, F.; Sasselov, D. D.; Schingler, R. H.; Seager, S.; Szentgyorgyi, A.; Torres, G.; Udry, S.; Villasenor, J. N.; Winn, J. N.; Worden, S. P.

2010-01-01

280

Geological effect of high-precise gravimetric and magnetic surveys in Yangqiao prospect in Biyang depression  

SciTech Connect

This paper reports on Yangqiao prospect in Biyang depression which is an area where very high-degree exploration has been done. The complicated seismic and geological conditions in the border area of the depression cause very poor seismic data, so that exact structural configuration can not be known. Thus, high-precise gravimetric-magnetic surveys were done. The interpretations of gravimetric and magnetic data are mainly based on the properties of gravitational and magnetic fields. Local gravimetric and magnetic anomalies at Wangzhuang were discovered by performing forward fitting of observed gravimetric and magnetic data. The repeated seismic interpretation by reference to the gravimetric-magnetic interpretation result confirms the existence of an anticline structure in the local gravimetric and magnetic anomaly area. The effect of direct hydrocarbon prediction using high- precise gravimetric and magnetic data were checked in known Anpeng and Xiaermen oil fields. The check shows good effect.

Rongyuan, W.; Zhaoling, Y.; Zhangmin, G.; Xiaoliu, W. (Geophysical Exploration Dept., China Geology Univ., Wuhan City, Hubei Probince (CN))

1991-01-01

281

High precision Penning trap mass spectrometry of rare isotopes produced by projectile fragmentation  

NASA Astrophysics Data System (ADS)

The Low Energy Beam and Ion Trap (LEBIT) facility combines high precision Penning trap mass spectrometry with fast beam projectile fragmentation and high pressure gas stopping techniques. Advanced ion manipulation, such as high efficiency continuous mass selection in an ion-guide and radio-frequency ion accumulation and bunching, are used to purify, cool, and pulse the beam. Recent mass measurements include ^63-66Fe, ^66As, and ^32Si. The neutron-rich iron isotopes access the N = 40 subshell closure. The new significantly lower mass uncertainty makes ^66As a candidate to test the CVC hypothesis. ^32Si, member of the A = 32, T = 2 quintet, provides the most precise test of the isobaric multiplet mass equation . An overview of the various aspects of ion manipulation and some of the resulting measurements will be presented.

Kwiatkowski, Anna; Bachelet, C.; Barquest, B. R.; Bollen, G.; Campbell, C. M.; Ferrer, R.; Guenaut, C.; Lincoln, D.; Morrissey, D. J.; Pang, G. K.; Prinke, A. M.; Ringle, R.; Savory, J.; Schwarz, S.; Block, M.; Schury, P.; Folden, C. M., III; Melconian, D.; Sjue, S. K. J.

2009-10-01

282

Design and study of the high-precision stepping motor control system for intelligent sampling of liquid  

Microsoft Academic Search

With the development of machinery and electronics toward digital and intelligent, the study of control system takes a very important role. The high-precision stepping motor control system for intelligent sampling of liquid achieves intelligent and high-precision sampling locations by the intelligent high-precision controlling of stepper motor. Stepper motor is the implementing agency that put an electrical pulse into the angular

Weiwei Hu; Jianjing Sun

2010-01-01

283

High-precision reflectometry of multilayer coatings for extreme ultraviolet lithography  

SciTech Connect

Synchrotron-based reflectometry is an important technique for the precise determination of optical properties of reflective multilayer coatings for Extreme Ultraviolet Lithography (EUVL). Multilayer coatings enable normal incidence reflectances of more than 65% in the wavelength range between 11 and 15 nm. In order to achieve high resolution and throughput of EUVL systems, stringent requirements not only apply to their mechanical and optical layout, but also apply to the optical properties of the multilayer coatings. Therefore, multilayer deposition on near-normal incidence optical surfaces of projection optics, condenser optics and reflective masks requires suitable high-precision metrology. Most important, due to their small bandpass on the order of only 0.5 nm, all reflective multilayer coatings in EUVL systems must be wavelength-matched to within {+-}0.05 nm. In some cases, a gradient of the coating thickness is necessary for wavelength matching at variable average angle of incidence in different locations on the optical surfaces. Furthermore, in order to preserve the geometrical figure of the optical substrates, reflective multilayer coatings need to be uniform to within 0.01 nm in their center wavelength. This requirement can only be fulfilled with suitable metrology, which provides a precision of a fraction of this value. In addition, for the detailed understanding and the further development of reflective multilayer coatings a precision in the determination of peak reflectances is desirable on the order of 0.1%. Substrates up to 200 mm in diameter and 15 kg in mass need to be accommodated. Above requirements are fulfilled at beamline 6.3.2 of the Advanced Light Source (ALS) in Berkeley. This beamline proved to be precise within 0.2% (ms) for reflectance and 0.002 nm (rms) for wavelength.

Wedowski, M; Underwood, J H; Gullikson, E M; Bajt, S; Folta, J A; Kearney, P A; Montcalm, C; Spiller, E

1999-12-29

284

Towards an order of magnitude improvement in high-precision atomic mass measurements  

NASA Astrophysics Data System (ADS)

The use of single ions in Penning traps has made possible the measurement of some atomic and molecular masses with a precision of about a part in 10^10. This is achieved by measuring the cyclotron frequency of an ion trapped in a strong magnetic field, and comparing it to the cyclotron frequency of a reference ion trapped in the same field several minutes later. The precision of these measurements is limited by fluctuations of the magnetic field. Recent improvements on the MIT mass spectrometer have opened the way to higher precision by allowing us to simultaneously confine and detect two different ions in the same trap. A direct measurement of the difference in the cyclotron frequencies of the two ions can then be completely insensitive to magnetic field fluctuations! The Coulomb interaction between the two ions introduces perturbations which can potentially cause systematic errors and are under study. Statistical uncertainties below a part in 10^11 are possible after only a few hours of measurement. The beauty and challenges of this technique will be presented as well as recent experimental results.

Rainville, Simon; Thompson, James K.; Pritchard, David E.

2001-05-01

285

All low voltage lateral junction scanning tunneling microscope with very high precision and stability.  

PubMed

We describe the first lateral junction and fully low voltage scanning tunneling microscope, featuring very high precision, stability, compactness, and image quality (highly oriented pyrolytic graphite atomic resolution images). In its core, the tip and sample each sit on one of two parallel-mounted piezoelectric tube scanners so that the tip-sample gap is regulated along the scanners' pairing direction. The scanner's large lateral deflection provides a large gap regulation range even under low voltages, allowing exclusively using only low voltage (less than +/-15 V) operational amplifiers to precisely implement the coarse (inertial slider) and fine approach, feedback control, and hence the entire electronics. Because the scanners are identical and adjacent, thermal drifts are minimal. PMID:19045895

Hou, Yubin; Wang, Jihui; Lu, Qingyou

2008-11-01

286

Using femtosecond laser to fabricate highly precise interior three-dimensional microstructures in polymeric flow chip  

PubMed Central

This paper reports using femtosecond laser marker to fabricate the three-dimensional interior microstructures in one closed flow channel of plastic substrate. Strip-like slots in the dimensions of 800 ?m×400 ?m×65 ?m were ablated with pulse Ti:sapphire laser at 800 nm (pulse duration of ?120 fs with 1 kHz repetition rate) on acrylic slide. After ablation, defocused beams were used to finish the surface of microstructures. Having finally polished with sonication, the laser fabricated structures are highly precise with the arithmetic roughness of 1.5 and 4.5 nm. Fabricating such highly precise microstructures cannot be accomplished with nanosecond laser marking or other mechanical drilling methods. In addition, since laser ablation can directly engrave interior microstructures in one closed chip, glue smearing problems to damage molded microstructures possibly to occur during the chip sealing procedures can be avoided too.

Lee, Chia-Yu; Chang, Ting-Chou; Wang, Shau-Chun; Chien, Chih-Wei; Cheng, Chung-Wei

2010-01-01

287

Investigation of cluster structure of {sup 9}Be from high precision elastic scattering data  

SciTech Connect

The cluster structure of {sup 9}Be has been investigated through high precision elastic scattering cross-section measurements of a {sup 9}Be + {sup 208}Pb system at below barrier energies, E= 24-34 MeV.The observed deviation from the Rutherford scattering can only be explained by an n + {sup 8}Be cluster description of {sup 9}Be, whereas the {alpha} + {sup 5}He cluster picture fails to explain the measured data, indicating the dominance of the n + {sup 8}Be cluster structure of {sup 9}Be. In addition to sequential and direct breakup, the coupling effect of one neutron stripping on elastic scattering is significant even at 10 MeV below the barrier. The sensitivity of the high precision elastic scattering data to the cluster structure of {sup 9}Be has been demonstrated.

Pandit, S. K.; Jha, V.; Mahata, K.; Santra, S.; Palshetkar, C. S.; Ramachandran, K.; Shrivastava, A.; Kumawat, H.; Roy, B. J.; Chatterjee, A.; Kailas, S. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai-400085 (India); Parkar, V. V. [Department of Nuclear and Atomic Physics, Tata Institute of Fundamental Research, Mumbai-400005 (India)

2011-09-15

288

High-precision and high-resolution carbonate 230Th dating by MC-ICP-MS with SEM protocols  

NASA Astrophysics Data System (ADS)

To facilitate the measurement of U-Th isotopic compositions suitable for high-precision and high-resolution 230Th dating of coral and speleothem carbonates, secondary electron multiplier (SEM) protocol techniques for multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) have been developed. The instrumental sensitivities are 1-2%, with a precision of ±1-2‰ (2?) for abundance determination of 50-200 fg 234U (1-4 ng 238U) or 230Th. This method features chemistry refinements, improvements to procedural and instrumental blanks, spectral inference reductions, and careful consideration of non-linear SEM behavior. Measurement consistency of this MC-ICP-MS combined with previous mass spectrometric results on U-Th standards and a variety of carbonates demonstrates the validity of the SEM protocol method. For fossil corals, a routine U-Th isotopic determination at permil-level precision requires only 10-50 mg of carbonate. As little as 200 mg of young coral with an age of less than 20 yr can be dated with a precision of ±0.3-0.8 yr. About 20-200 mg speleothem samples with sub-ppm-to-ppm U are required to earn a 5‰ precision on ages from 5 to 100 kyr. Requirement of small sample size, 10-100s mg carbonate, can permit high temporal resolution to date speleothems with slow growth rates, i.e., 1-10 mm/kyr. This high-precision 230Th chronology is critical to accurately establish age models, date events and splice geochemical proxy time series records from multiple samples in the fields of paleoclimatology and paleoceanography. The U-Th isotopic determination techniques described here can also be applied to different environmental samples, such as waters, rocks, and sediments.

Shen, Chuan-Chou; Wu, Chung-Che; Cheng, Hai; Lawrence Edwards, R.; Hsieh, Yu-Te; Gallet, Sylvain; Chang, Ching-Chih; Li, Ting-Yong; Lam, Doan Dinh; Kano, Akihiro; Hori, Masako; Spötl, Christoph

2012-12-01

289

Electromagnetic controlled cortical impact device for precise, graded experimental traumatic brain injury.  

PubMed

Genetically modified mice represent useful tools for traumatic brain injury (TBI) research and attractive preclinical models for the development of novel therapeutics. Experimental methods that minimize the number of mice needed may increase the pace of discovery. With this in mind, we developed and characterized a prototype electromagnetic (EM) controlled cortical impact device along with refined surgical and behavioral testing techniques. By varying the depth of impact between 1.0 and 3.0 mm, we found that the EM device was capable of producing a broad range of injury severities. Histologically, 2.0-mm impact depth injuries produced by the EM device were similar to 1.0-mm impact depth injuries produced by a commercially available pneumatic device. Behaviorally, 2.0-, 2.5-, and 3.0-mm impacts impaired hidden platform and probe trial water maze performance, whereas 1.5-mm impacts did not. Rotorod and visible platform water maze deficits were also found following 2.5- and 3.0-mm impacts. No impairment of conditioned fear performance was detected. No differences were found between sexes of mice. Inter-operator reliability was very good. Behaviorally, we found that we could statistically distinguish between injury depths differing by 0.5 mm using 12 mice per group and between injury depths differing by 1.0 mm with 7-8 mice per group. Thus, the EM impactor and refined surgical and behavioral testing techniques may offer a reliable and convenient framework for preclinical TBI research involving mice. PMID:17439349

Brody, David L; Mac Donald, Christine; Kessens, Chad C; Yuede, Carla; Parsadanian, Maia; Spinner, Mike; Kim, Eddie; Schwetye, Katherine E; Holtzman, David M; Bayly, Philip V

2007-04-01

290

Electromagnetic Controlled Cortical Impact Device for Precise, Graded Experimental Traumatic Brain Injury  

PubMed Central

Genetically modified mice represent useful tools for traumatic brain injury (TBI) research and attractive preclinical models for the development of novel therapeutics. Experimental methods that minimize the number of mice needed may increase the pace of discovery. With this in mind, we developed and characterized a prototype electromagnetic (EM) controlled cortical impact device along with refined surgical and behavioral testing techniques. By varying the depth of impact between 1.0 and 3.0 mm, we found that the EM device was capable of producing a broad range of injury severities. Histologically, 2.0-mm impact depth injuries produced by the EM device were similar to 1.0-mm impact depth injuries produced by a commercially available pneumatic device. Behaviorally, 2.0-, 2.5-, and 3.0-mm impacts impaired hidden platform and probe trial water maze performance, whereas 1.5-mm impacts did not. Rotorod and visible platform water maze deficits were also found following 2.5- and 3.0-mm impacts. No impairment of conditioned fear performance was detected. No differences were found between sexes of mice. Inter-operator reliability was very good. Behaviorally, we found that we could statistically distinguish between injury depths differing by 0.5 mm using 12 mice per group and between injury depths differing by 1.0 mm with 7-8 mice per group. Thus, the EM impactor and refined surgical and behavioral testing techniques may offer a reliable and convenient framework for preclinical TBI research involving mice.

BRODY, DAVID L.; DONALD, CHRISTINE Mac; KESSENS, CHAD C.; YUEDE, CARLA; PARSADANIAN, MAIA; SPINNER, MIKE; KIM, EDDIE; SCHWETYE, KATHERINE E.; HOLTZMAN, DAVID M.; BAYLY, PHILIP V.

2008-01-01

291

Development of a micro catalytic combustor using high-precision ceramic tape casting  

Microsoft Academic Search

A micro-scale catalytic combustor fueled by butane was investigated. High-precision ceramic tape-casting technology was adopted for developing a three-dimensional structure of the combustor with embedded heat exchange channels. Nano-porous alumina fabricated through anodic oxidation of aluminum layers was employed for the support of Pd catalyst. Combustion experiments were carried out in a solder bath to keep the catalyst temperature constant.

Takashi Okamasa; Gwang-Goo Lee; Yuji Suzuki; Nobuhide Kasagi; Shin Matsuda

2006-01-01

292

Development of high-precision temperature measurement system based on ARM  

Microsoft Academic Search

The high-precision temperature measurement system which adopts ARM processor LM3S1138 as controlling core was introduced in this paper. In the temperature measuring circuits, the current driving circuit of sensor Pt100A and A\\/D converting circuit adopt the same reference voltage, which makes A\\/D conversion results are only dependent on the changing value of platinum resistance with the temperature change DeltaRT, and

Yi Xianjun; Liu Cuimei

2009-01-01

293

MCU-PTR program for high-precision calculations of pool and tank type research reactors  

Microsoft Academic Search

The MCU-PTR program with a MDBPTR50 database has been developed. The purpose of this program is to perform high-precision\\u000a mathematical modeling of nuclear reactors and to calculate their neutron-physical characteristics. The program uses the Monte-Carlo\\u000a method to solve the equations governing n, ? radiation transfer and uses evaluated data describing the interaction of neutrons and photons with matter. The change

N. I. Alekseev; E. A. Gomin; S. V. Marin; V. A. Nasonov; D. A. Shkarovskii; M. S. Yudkevich

2011-01-01

294

High-precision infrared pulse laser ranging for active vehicle anti-collision application  

Microsoft Academic Search

In this work, a high-precision infrared pulse laser ranging system based on FPGA and microcontroller Atmel16 is proposed for active vehicle anti-collision application, and the key technologies of this system including optical device, laser receiver component, and time-of-flight stretching component are studied deeply based on the principle of the pulse laser time-of-flight measurement. The light energy transmission is analyzed in

Yandong Chen; Zhiqiang Meng; Jinglin Liu; Heping Jiang

2011-01-01

295

A 100000-A high precision on-site measurement calibration device for heavy direct current  

Microsoft Academic Search

A 100000-A, high precision device of the magnetic modulation current comparator type, which can be used in industrial heavy direct current systems for online calibration and measurement, is presented. Testing of the comparator indicates that its current ratio accuracy is 5×10-5, and that measurements of voltage with a standard resistor achieve an accuracy of 5×10-4. These are slightly degraded to

SHIYAN REN

1990-01-01

296

High-precision calculations of atomic properties and parity nonconservation in systems with one valence electron  

Microsoft Academic Search

High-precision calculations of atomic properties of systems with one valence electron outside of a closed core are carried out using a relativistic all-order method. The method used here is a linearized version of coupled-cluster method which sums infinite sets of many- body perturbation theory terms. Energy levels are calculated for the ground state and five excited states of sodium and

Marianna Suyatoslavna Safronova

2001-01-01

297

Study on controller designs for high-precisely linear piezoelectric ceramic motor (LPCM)  

Microsoft Academic Search

The aim of this paper is an observation of PID, fuzzy, sliding mode (SM) and fuzzy-sliding mode (FSM) controllers for high-precisely linear piezoelectric ceramic motor (LPCM). By understanding the characteristics of each single controller, one of the advantages is well-knowledge, when those controllers will be used, and what drawbacks they have. This paper exhibit a comparison of their error-reduction performance.

Hendro Nurhadi; Whei-Ming Kuo; Yeong-Shin Tarng

2010-01-01

298

Thermo-optic noise in coated mirrors for high-precision optical measurements  

SciTech Connect

Thermal fluctuations in the coatings used to make high reflectors are becoming significant noise sources in precision optical measurements and are particularly relevant to advanced gravitational-wave detectors. There are two recognized sources of coating thermal noise; mechanical loss and thermal dissipation. Thermal dissipation causes thermal fluctuations in the coating which produce noise via the thermoelastic and thermorefractive mechanisms. We treat these mechanisms coherently, give a correction for finite coating thickness, and evaluate the implications for Advanced LIGO.

Evans, M.; Fritschel, P.; Harry, G. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Ballmer, S.; Ogin, G. [California Institute of Technology, Pasadena, California 91125 (United States); Fejer, M. [Stanford University, Stanford, California 94305 (United States)

2008-11-15

299

The performance of a high-precision photometry mission in space  

Microsoft Academic Search

For approximately 17 months during 1999-2000, the star tracker camera on board the Wide-Field Infrared Explorer (WIRE) satellite was used as an instrument to perform high-precision photometry in space. In this paper, I summarize the operating characteristics of the instrument, the data analysis techniques developed to support WIRE's new mission, and some recent scientific results. In addition, I discuss lessons

D. L. Buzasi

2004-01-01

300

Copper vapor laser MOPA-chain for highly efficient and precise material removal  

Microsoft Academic Search

Copper vapor lasers in a MOPA-chain (MOPA, master-oscillator- power-amplifier) configuration with low divergence can be used for the high precision machining of metals and ceramics. The fundamental interaction phenomena, ablation process and possible industrial applications are presented. The following paper relates the results and experiences in the operation of a copper vapor laser MOPA chain, consisting of an oscillator and

Karsten Schutte; Eric K. Gan; Juergen Koch; Adolf Lang; Martin Hartmann; Roland Mayerhofer; Tomas Slunecko; Hans W. Bergmann

1997-01-01

301

Algorithmic Design of High-Precision Low-Power MultiStage Decimation Filters  

Microsoft Academic Search

An algorithm for design of high-precision low- power decimation filters for DeltaSigma analog-to-digital converters is described. This algorithm has been applied to decimation filters with oversampling ratios of 32 to 256, passband ripples of 2 to 0.0003 dB, stopband attenuation of -30 to -120 dB, and passband edge of 0.35 fs to 0.454 fs, where fs is the output sampling

S. M. Mortazavi Zanjani; S. Rahimian Omam; S. M. Fakhraie; O. Shoaei

2006-01-01

302

High-precision gravity network to monitor temporal variations in gravity across Yucca Mountain, Nevada  

SciTech Connect

Repeatable high-precision gravity surveys provide a method of monitoring temporal variations in the gravity field. Fluctuations in the gravity field may indicate water table changes, crustal deformation, or precursors to volcanism and earthquakes. This report describes a high-precision gravity loop which has been established across Yucca Mountain, Nevada in support of the Nevada Nuclear Waste Storage Investigations (NNWSI) program. The purpose of this gravity loop is to monitor temporal variations in gravity across Yucca Mountain in an effort to interpret and predict the stability of the tectonic framework and changes in the subsurface density field. Studies of the tectonic framework which include volcanic hazard seismicity, and faulting studies are in progress. Repeat high-precision gravity surveys are less expensive and can be made more rapidly than a corresponding leveling survey. High-precision gravity surveys are capable of detecting elevation changes of 3 to 5 cm, and thus can be employed as an efficient tool for monitoring vertical crustal movements while supplementing or partially replacing leveling data. The Yucca Mountain gravity network has been tied to absolute gravity measurements established in southern Nevada. These ties provide an absolute datum for comparing repeat occupations of the gravity network, and provide a method of monitoring broad-scale changes in gravity. Absolute gravity measurements were also made at the bottom and top of the Charleston Peak calibration loop in southern Nevada. These absolute gravity measurements provide local control of calibrating gravity meters over the gravity ranges observed at Yucca Mountain. 13 refs., 7 figs., 3 tabs.

Harris, R.N.; Ponce, D.A.

1988-12-31

303

Verification program for a high-precision large cryogenic lens holder  

Microsoft Academic Search

For the Euclid mission a Pre-Development phase is implemented to prove feasibility of individual components of the system. The Near Infrared Spectrometer and Photometer (NISP) of EUCLID requires high precision and large lens holders (Ø170 mm) at cryogenic temperatures (120K - 150K). The four lenses of the optical system are made of different materials: fused silica, CaF2, and LF5G15 that

A. Boesz; F. Grupp; T. Leberle; A. Mottaghibonab; N. Geis; R. Bender

2011-01-01

304

Establishing ground control points for high-resolution satellite imagery using GPS precise point positioning  

Microsoft Academic Search

A GPS measurement and processing technique of precise point positioning (PPP) accurate to 2.5 m is developed for the purpose of establishing ground control points (GCPs) for rectifying medium and high resolution satellite imageries. In practice, the coordinates necessary in geometric rectification are usually derived from medium scale maps such as 1;50,000 or 1:25,000 scale topographic maps. However, the total

Chalermchon Satirapod; I. Trisirisatayawong; P. Homniam

2003-01-01

305

New High-precision Reference Pressure Transducers from 1 MPa to 50 MPa  

Microsoft Academic Search

Calibration laboratories prefer to use piston manometers (dead-weight testers) for calibrating pressures in the range from a few pascals up to 1 000 MPa. The high-precision pressure transducer P31AP is an alternative that can be calibrated as a secondary pressure standard and used as a reference pressure transducer. When using reference pressure transducers a simple manual or motor-driven pressure source

H. Paul

1994-01-01

306

High-precision analysis of Pb isotope ratios by multi-collector ICP-MS  

Microsoft Academic Search

We investigated high-precision Pb isotope ratio analysis by multi-collector-inductively coupled plasma-mass spectrometry (MC-ICP-MS) using added thallium as an internal isotopic standard to correct for mass dependent isotopic fractionation. We compared MC-ICP-MS analysis of both an inter-laboratory standard, NBS 981, and geological samples to conventional thermal ionization mass spectrometry (TIMS). As expected, we found that analytical error in the latter was

William M White; Francis Albarède; Philippe Télouk

2000-01-01

307

High precision, low cost mask for deep x-ray lithography  

Microsoft Academic Search

The precision of transferred patterns are highly dependent on the quality of the mask in deep x-ray lithography. Many parameters,\\u000a such as the critical energy of the synchrotron light, beamline optics and even the microstructure to be exposed should be\\u000a considered in mask design. In this paper, the design rules and the boundary conditions for deep x-ray mask are discussed

B.-Y. Shew; Y. Cheng; W.-P. Shih; M. Lu; W. H. Lee

1998-01-01

308

A high precision gamma-ray spectrometer for the Mars-94 mission  

SciTech Connect

The high precision gamma-ray spectrometer (PGS) is scheduled to be launched on the Mars-94 mission in October 1994, and to go into an elliptical polar orbit around Mars. The PGS consists of two high-purity germanium (Ge) detectors, associated electronics, and a passive cooler and will be mounted on one of the solar panels. The PGS will measure nuclear gamma-ray emissions from the martian surface, cosmic gamma-ray bursts, and the high-energy component of solar flares in the broad energy range from 50 KeV to 8 MeV using 4096 energy channels.

Mitrofanov, I.G.; Anfimov, D.S.; Chernenko, A.M. [Inst. for Space Research, Moscow (Russian Federation)] [and others

1994-06-01

309

High precision U-PB geochronology and implications for the tectonic evolution of the Superior Province  

NASA Astrophysics Data System (ADS)

The underlying mechanisms of Archean tectonics and the degree to which modern plate tectonic models are applicable early in Earth's history continue to be a subject of considerable debate. A precise knowledge of the timing of geological events is of the utmost importance in studying this problem. The high precision U-Pb method has been applied in recent years to rock units in many areas of the Superior Province. Most of these data have precisions of about + or - 2-3 Ma. The resulting detailed chronologies of local igneous development and the regional age relationships furnish tight constraints on any Archean tectonic model. Superior province terrains can be classified into 3 types: (1) low grade areas dominated by meta-volcanic rocks (greenstone belts); (2) high grade, largely metaplutonic areas with abundant orthogneiss and foliated to massive I-type granitoid bodies; and (3) high grade areas with abundant metasediments, paragneiss and S-type plutons. Most of the U-Pb age determinations have been done on type 1 terrains with very few having been done in type 3 terrains. A compilation of over 120 ages indicates that the major part of igneous activity took place in the period 2760-2670 Ma, known as the Kenoran event. This event was ubiquitous throughout the Superior Province.

Davis, D. W.; Corfu, F.; Krogh, T. E.

310

Theoretical and experimental research on machine tool servo system for ultra-precision position compensation on CNC lathe  

NASA Astrophysics Data System (ADS)

The theories and techniques for improving machining accuracy via position control of diamond tool's tip and raising resolution of cutting depth on precise CNC lathes have been extremely focused on. A new piezo-driven ultra-precision machine tool servo system is designed and tested to improve manufacturing accuracy of workpiece. The mathematical model of machine tool servo system is established and the finite element analysis is carried out on parallel plate flexure hinges. The output position of diamond tool's tip driven by the machine tool servo system is tested via a contact capacitive displacement sensor. Proportional, integral, derivative (PID) feedback is also implemented to accommodate and compensate dynamical change owing cutting forces as well as the inherent non-linearity factors of the piezoelectric stack during cutting process. By closed loop feedback controlling strategy, the tracking error is limited to 0.8 ?m. Experimental results have shown the proposed machine tool servo system could provide a tool positioning resolution of 12 nm, which is much accurate than the inherent CNC resolution magnitude. The stepped shaft of aluminum specimen with a step increment of cutting depth of 1 ?m is tested, and the obtained contour illustrates the displacement command output from controller is accurately and real-time reflected on the machined part.

Ma, Zhichao; Hu, Leilei; Zhao, Hongwei; Wu, Boda; Peng, Zhenxing; Zhou, Xiaoqin; Zhang, Hongguo; Zhu, Shuai; Xing, Lifeng; Hu, Huang

2010-08-01

311

Early Results from A Global Network of Extremely High Precision Extrasolar Planet Tracker Instruments  

NASA Astrophysics Data System (ADS)

We report early results from two of the Extremely High Precision Extrasolar Planet Tracker Instruments (EXPERT) as part of a global network for hunting for low mass planets in the next decade. The first EXPERT was commissioned at the Kitt Peak 2.1m in September 2009 and the second one is to be commissioned at the LiJiang 2.4m telescope in December 2009. EXPERT is a combination of a thermally compensated monolithic interferometer and a high throughput cross-dispersed echelle spectrograph with a spectral resolution of R=18,000. It covers 0.39-0.7 ?m in a single exposure. The commissioning data shows that we have reached a Doppler precision of about 1 m/s for a solar type star with S/N 100 per pixel using an early version of data pipeline with iodine absorption calibration (0.5-0.6 ?m only), which is consistent with our original design. We also achieved slightly better than R=18,000 spectral resolution, about 10 mK temperature stability over a few days, a total detection efficiency of 18.8% from the telescope fiber tip to the detector at 0.55 ?m. The final predicted Doppler precision based on ThAr calibration being developed to cover the entire operating wavelengths is about 0.5 m/s. Our goal is to populate six 2 meter class telescopes with the EXPERT instruments across the globe to have more than 90% duty cycle for time sensitive extremely high precision Doppler measurements such as hunting for Earth like rocky planets and studying stellar oscillations. The network will also be used for following up planet candidates from the on-going SDSS-III Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS) and space missions. We acknowledge support from W.M. Keck Foundation, NSF, Chinese NSF, UF and the LiJET consortium.

Ge, Jian; Chang, L.; Groot, J.; Wan, X.; Zhao, B.; Varosi, F.; Hanna, K.; Jiang, P.; Fleming, S.; Lee, B.; Pais, R.; Wang, J.; Dou, L.; Liu, J.; Costello, E.; Delgado-Navarro, A.; Bollampally, S.; Bosman, T.; Powell, S.; Wang, T.; Wang, T.; Yuan, W.; Zhou, J.; Zhou, H.

2010-01-01

312

Precision of high-resolution multibeam echo sounding coupled with high-accuracy positioning in a shallow water coastal environment  

NASA Astrophysics Data System (ADS)

Over 4 years, repetitive bathymetric measurements of a shipwreck in the Grådyb tidal inlet channel in the Danish Wadden Sea were carried out using a state-of-the-art high-resolution multibeam echosounder (MBES) coupled with a real-time long range kinematic (LRK™) global positioning system. Seven measurements during a single survey in 2003 ( n=7) revealed a horizontal and vertical precision of the MBES system of ±20 and ±2 cm, respectively, at a 95% confidence level. By contrast, four annual surveys from 2002 to 2005 ( n=4) yielded a horizontal and vertical precision (at 95% confidence level) of only ±30 and ±8 cm, respectively. This difference in precision can be explained by three main factors: (1) the dismounting of the system between the annual surveys, (2) rougher sea conditions during the survey in 2004 and (3) the limited number of annual surveys. In general, the precision achieved here did not correspond to the full potential of the MBES system, as this could certainly have been improved by an increase in coverage density (soundings/m2), achievable by reducing the survey speed of the vessel. Nevertheless, precision was higher than that reported to date for earlier offshore test surveys using comparable equipment.

Ernstsen, Verner B.; Noormets, Riko; Hebbeln, Dierk; Bartholomä, Alex; Flemming, Burg W.

2006-09-01

313

The high-precision videometrics methods to determining absolute vertical benchmark  

NASA Astrophysics Data System (ADS)

The mobile measurement equipment plays an important role in engineering measurement tasks and its measuring device is fixed with the vehicle platform. Therefore, how to correct the measured error in time that caused by swayed platform is a basic problem. Videometrics has its inherent advantages in solving this problem. First of all, videometrics technology is non-contact measurement, which has no effect on the target's structural characteristics and motion characteristics. Secondly, videometrics technology has high precision especially for surface targets and linear targets in the field of view. Thirdly, videometrics technology has the advantages of automatic, real-time and dynamic. This paper is mainly for mobile theodolite.etc that works under the environment of absolute vertical benchmark and proposed two high-precision methods to determine vertical benchmark: Direct-Extracting, which is based on the intersection of plats under the help of two cameras; Benchmark-Transformation, which gets the vertical benchmark by reconstructing the level-plat. Two methods both have the precision of under 10 seconds by digital simulation and physical experiments. The methods proposed by this paper have significance both on the theory and application.

Liu, Jinbo; Zhu, Zhaokun

2013-01-01

314

High-precision masses of neutron-deficient rubidium isotopes using a Penning trap mass spectrometer  

SciTech Connect

The atomic masses of the neutron-deficient radioactive rubidium isotopes {sup 74-77,79,80,83}Rb have been measured with the Penning trap mass spectrometer ISOLTRAP. Using the time-of-flight cyclotron resonance technique, relative mass uncertainties ranging from 1.6x10{sup -8} to 5.6x10{sup -8} were achieved. In all cases, the mass precision was significantly improved as compared with the prior Atomic-Mass Evaluation; no significant deviations from the literature values were observed. The exotic nuclide {sup 74}Rb, with a half-life of only 65 ms, is the shortest-lived nuclide on which a high-precision mass measurement in a Penning trap has been carried out. The significance of these measurements for a check of the conserved-vector-current hypothesis of the weak interaction and the unitarity of the Cabibbo-Kobayashi-Maskawa matrix is discussed.

Kellerbauer, A. [Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Audi, G.; Guenaut, C.; Lunney, D. [CSNSM-IN2P3-CNRS, F-91405 Orsay-Campus (France); Beck, D.; Herfurth, F.; Kluge, H.-J.; Weber, C.; Yazidjian, C. [GSI, Planckstrasse 1, D-64291 Darmstadt (Germany); Blaum, K. [GSI, Planckstrasse 1, D-64291 Darmstadt (Germany); Institut fuer Physik, Johannes-Gutenberg-Universitaet, D-55099 Mainz (Germany); Bollen, G.; Schwarz, S. [NSCL, Michigan State University, East Lansing, Michigan 48824-1321 (United States); Herlert, A.; Schweikhard, L. [Institut fuer Physik, Ernst-Moritz-Arndt-Universitaet, D-17487 Greifswald (Germany)

2007-10-15

315

Measuring instrument for radial composite deviations of high-precision master gear  

NASA Astrophysics Data System (ADS)

During double flank rolling composite detection, the radial composite deviations of master gears has been existed and transferred to the measured gear by the primary harmonic curve. In order to improve measurement accuracy, a measuring instrument is developed for radial composite deviations of high-precision master gear in the paper. This instrument uses the structure of spring-suspend swing span to overcome the shortcomings of large rotation errors, low sensitivity, low resolution and large measuring force appearing in the traditional combination-type gear inspection instrument. Artificial intelligence technology is used to improve the efficiency and accuracy of this instrument. The result is that the measuring apparatus is able to meet the requirement and improve efficiency through the measuring experiments on master gears of precision grade 2 with modulus 2 mm and 3 mm, respectively.

Ma, Yong; Wang, Tongxiang; Lou, Zhifeng; Wang, Liding; Zhang, Yuling

2010-08-01

316

Mechanisms of Archean crust formation inferred from high-precision HFSE systematics in TTGs  

NASA Astrophysics Data System (ADS)

It has been proposed that Archean tonalitic-trondhjemitic-granodioritic magmas (TTGs) formed by melting of mafic crust at high pressures. The residual mineralogy of the TTGs (either (garnet)-amphibolite or rutile-bearing eclogite) is believed to control the trace element budget of TTGs. In particular, ratios of high-field-strength elements (HFSE) can help to discriminate between the different residual lithologies. In order to place constraints on the source mineralogy of TTGs, we performed high-precision HFSE measurements by isotope dilution (Nb, Ta, Zr, Hf) together with Lu-Hf and Sm-Nd measurements on representative, ca. 3.85-2.8 Ga TTGs and related rock types from southern West Greenland, W-India and from the Superior Province. These measurements are complemented by major and trace element data for the TTGs. Texturally homogeneous early Archean (3.85-3.60 Ga old) and Mesoarchean (ca. 3.1-2.8 Ga old) TTGs have both low Ni (<11 ppm) and Cr contents (<20 ppm), indicating that there was little or no interaction with mantle peridotite during ascent. Ratios of Nb/Ta in juvenile Eoarchean TTGs range from ca. 7 to ca. 24, and in juvenile Mesoarchean TTGs from ca. 14 to ca. 27. Even higher Nb/Ta (14-42) were obtained for migmatitic TTGs and intra-crustal differentiates, most likely mirroring further fractionation of Nb from Ta as a consequence of partial melting, fluid infiltration and migmatisation. In the juvenile TTGs, positive correlations between Nb/Ta and Gd/Yb, La/Yb, Sr/Y, Zr/Sm and Zr/Nb are observed. These compositional arrays are best explained by melting of typical Isua tholeiites in both, the rutile-bearing eclogite stability field (>15 kbar, high Nb/Ta) and the garnet-amphibolite stability field (10-15 kbar, low Nb/Ta). With respect to the low end of Nb/Ta found for TTGs, there is currently some uncertainty between the available experimental datasets for amphibole. Independent of these uncertainties, the TTG compositions found here still require the presence of both endmember residues. A successful geological model for the TTGs therefore has to account for the co-occurrence of both low- and high-Nb/Ta TTGs within the same geologic terrane. An additional feature observed in the Eoarchean samples from Greenland is a systematic co-variation between Nb/Ta and initial ?Hf(t), which is best explained by a model where TTG-melting occured at progressively increasing pressures in a pile of tectonically thickened mafic crust. The elevated Nb/Ta in migmatitic TTGs and intra-crustal differentiates can shed further light on the role of intra-crustal differentiation processes in the global Nb/Ta cycle. Lower crustal melting processes at granulite facies conditions may generate high-Nb/Ta domains in the middle crust, whereas mid-crustal melting at amphibolite facies conditions may account for the low Nb/Ta generally observed in upper crustal rocks.

Hoffmann, J. Elis; Münker, Carsten; Næraa, Tomas; Rosing, Minik T.; Herwartz, Daniel; Garbe-Schönberg, Dieter; Svahnberg, Henrik

317

Fabrication of high precision metallic freeform mirrors with magnetorheological finishing (MRF)  

NASA Astrophysics Data System (ADS)

The fabrication of complex shaped metal mirrors for optical imaging is a classical application area of diamond machining techniques. Aspherical and freeform shaped optical components up to several 100 mm in diameter can be manufactured with high precision in an acceptable amount of time. However, applications are naturally limited to the infrared spectral region due to scatter losses for shorter wavelengths as a result of the remaining periodic diamond turning structure. Achieving diffraction limited performance in the visible spectrum demands for the application of additional polishing steps. Magnetorheological Finishing (MRF) is a powerful tool to improve figure and finish of complex shaped optics at the same time in a single processing step. The application of MRF as a figuring tool for precise metal mirrors is a nontrivial task since the technology was primarily developed for figuring and finishing a variety of other optical materials, such as glasses or glass ceramics. In the presented work, MRF is used as a figuring tool for diamond turned aluminum lightweight mirrors with electroless nickel plating. It is applied as a direct follow-up process after diamond machining of the mirrors. A high precision measurement setup, composed of an interferometer and an advanced Computer Generated Hologram with additional alignment features, allows for precise metrology of the freeform shaped optics in short measuring cycles. Shape deviations less than 150 nm PV / 20 nm rms are achieved reliably for freeform mirrors with apertures of more than 300 mm. Characterization of removable and induced spatial frequencies is carried out by investigating the Power Spectral Density.

Beier, Matthias; Scheiding, Sebastian; Gebhardt, Andreas; Loose, Roman; Risse, Stefan; Eberhardt, Ramona; Tünnermann, Andreas

2013-09-01

318

A prepositioned highly precision voltage regulator of AC regulated power supply based on single-chip micro-computer  

Microsoft Academic Search

This paper presents a novel prepositioned highly precision voltage regulator method based on single-chip micro-computer, uses a timing AC Servo Power Supply to make use of servo motor controlling Autotransformer, explains the working principle of the circuit, gives flowchart software, hardware block diagram and circuit schematic diagram. The realization of intelligent prepositioned highly precision voltage regulator and timing AC servo

Liu Zhen-ya; Chen Rong; Jiang Yan-hu; Liu Xiao-wei; Zhu Li-xing

2010-01-01

319

High precision atomic data for halo nuclei and related nuclear structure  

NASA Astrophysics Data System (ADS)

Nuclear charge radii of the lightest neutron-halo isotopes 6,8He, 11Li, and 11Be have been measured during the last decade using tailored laser-spectroscopic techniques for the needs of high-accuracy isotope shift measurements on millisecond-isotopes with very low production yields. Nuclear charge radii can be extracted using high-precision calculations of the mass-shift contribution and the electronic factor of the finite-nuclear-size effect. These results are important benchmarks for nuclear structure theory and give access to the correlations between halo neutrons and average distances of the halo neutrons from the core nucleus.

Nörtershäuser, Wilfried

2013-07-01

320

Theoretical and experimental high energy physics  

SciTech Connect

This report discusses experimental and theoretical work in High Energy Physics. Some topics discussed are: quantum field theory; supersymmetry; cosmology; superstring model; relic photinos; inflationary universe; dark matter; standard model; supernovae; semileptonic decay; quantum Langevin equation; underground neutrino detection at Soudan; strange quark systems; cosmic ray detection; superconducting super collider detectors; and studies of direct photon production. (LSP)

Gasiorowicz, S.; Ruddick, K.

1988-01-01

321

SEMICONDUCTOR INTEGRATED CIRCUITS: Design and implementation of a high precision and wide range adjustable LED drive controller  

NASA Astrophysics Data System (ADS)

This paper presents a novel high precision and wide range adjustable LED constant-current drive controller design. Compared with the traditional technique, the conventional mirror resistance is substituted by a MOSFET with fixed drain voltage, and a negative feedback amplifier is used to keep all mirror device voltages equal, so that the output current is precise and not affected by the load supply voltage. In addition, the electric property of the mirror MOSFET is optimized by a current subsection mirror (CSM) mechanism, thus ensuring a wide range of output current with high accuracy. A three-channel LED driver chip based on this project is designed and fabricated in the TSMC 0.6 ?m BCD process with a die area of 1.1 × 0.7 mm2. Experimental results show that the proposed LED drive controller works well, and, as expected, the output current can be maintained from 5 to 60 mA. A relative current accuracy error of less than 1% and a maximal relative current matching error of 1.5% are successfully achieved.

Guoding, Dai; Feng, Yu; Xuan, Wang; Weimin, Li

2010-02-01

322

An experimental study of highly lazy plumes  

NASA Astrophysics Data System (ADS)

We present results from an experimental study of highly lazy turbulent plumes, i.e. plumes with relatively low source momentum flux, or equivalently very large source Richardson numbers. Experimental observations indicate that the plumes contract as they move vertically away from the source and that the extent of the contraction is independent of the source Richardson number (consistent with previous experimental studies). Using the experimental technique developed by Baines (1983), we made volume flux measurements in the near source region of the plume. Our experimental results indicate that the volume flux increases linearly with distance from the source and scales with the source Richardson number to the one third power. This result is discussed in relation to existing entrainment models for forced plumes (low source Richardson number) and we demonstrate that these do not adequately describe the near source region of highly lazy plumes. It is also noted that the near source behaviour is similar to that of a line plume and a possible explanation for this behaviour is presented. Baines, W.D. (1983), ``A technique for the direct measurement of volume flux of a plume,'' J. Fluid Mech. 132, 247--256.

Kaye, Nigel; Hunt, Gary

2006-11-01

323

High-precision determination of iron oxidation state in silicate glasses using XANES  

SciTech Connect

Fe K-edge X-ray absorption near-edge structure (XANES) and Moessbauer spectra were collected on natural basaltic glasses equilibrated over a range of oxygen fugacity (QFM - 3.5 to QFM + 4.5). The basalt compositions and fO{sub 2} conditions were chosen to bracket the natural range of redox conditions expected for basalts from mid-ocean ridge, ocean island, back-arc basin, and arc settings, in order to develop a high-precision calibration for the determination of Fe{sup 3+}/{Sigma}Fe in natural basalts. The pre-edge centroid energy, corresponding to the 1s {yields} 3d transition, was determined to be the most robust proxy for Fe oxidation state, affording significant advantages compared to the use of other spectral features. A second-order polynomial models the correlation between the centroid and Fe{sup 3+}/{Sigma}Fe, yielding a precision of {+-} 0.0045 in Fe{sup 3+}/{Sigma}Fe for glasses with Fe{sup 3+}/{Sigma}Fe > 8%, which is comparable to the precision of wet chemistry. This high precision relies on a Si (311) monochromator to better define the Fe{sup 2+} and Fe{sup 3+} transitions, accurate and robust modeling of the pre-edge feature, dense fO{sub 2}-coverage and compositional appropriateness of reference glasses, and application of a non-linear drift correction. Through re-analysis of the reference glasses across three synchrotron beam sessions, we show that the quoted precision can be achieved (i.e., analyses are reproducible) across multiple synchrotron beam sessions, even when spectral collection conditions (detector parameters or sample geometry) change. Rhyolitic glasses were also analyzed and yield a higher centroid energy at a given Fe{sup 3+}/{Sigma}Fe than basalts, implying that major variations in melt structure affect the relationship between centroid position and Fe{sup 3+}/{Sigma}Fe, and that separate calibrations are needed for the determination of oxidation state in basalts and rhyolites.

Cottrell, Elizabeth; Kelley, Katherine A.; Lanzirotti, Antonio; Fischer, Rebecca A.; (Rhode Island); (UC); (Smithsonian)

2009-11-04

324

High precision differential abundance measurements in globular clusters: chemical inhomogeneities in NGC 6752  

NASA Astrophysics Data System (ADS)

We report on a strictly differential line-by-line analysis of high-quality UVES spectra of bright giants in the metal-poor globular cluster NGC 6752. We achieved high precision differential chemical abundance measurements for Fe, Na, Si, Ca, Ti, Cr, Ni, Zn, Y, Zr, Ba, La, Ce, Pr, Nd, Sm, Eu and Dy with uncertainties as low as ˜0.01 dex (˜2 per cent). We obtained the following main results. (1) The observed abundance dispersions are a factor of ˜2 larger than the average measurement uncertainty. (2) There are positive correlations, of high statistical significance, between all elements and Na. (3) For any pair of elements, there are positive correlations of high statistical significance, although the amplitudes of the abundance variations are small. Removing abundance trends with effective temperature and/or using a different pair of reference stars does not alter these results. These abundance variations and correlations may reflect a combination of (a) He abundance variations and (b) inhomogeneous chemical evolution in the pre- or protocluster environment. Regarding the former, the current constraints on ?Y from photometry likely preclude He as being the sole explanation. Regarding the latter, the nucleosynthetic source(s) must have synthesized Na, ?, Fe-peak and neutron-capture elements and in constant amounts for species heavier than Si; no individual object can achieve such nucleosynthesis. We speculate that other, if not all, globular clusters may exhibit comparable abundance variations and correlations to NGC 6752 if subjected to a similarly precise analysis.

Yong, David; Meléndez, Jorge; Grundahl, Frank; Roederer, Ian U.; Norris, John E.; Milone, A. P.; Marino, A. F.; Coelho, P.; McArthur, Barbara E.; Lind, K.; Collet, R.; Asplund, Martin

2013-10-01

325

Precise Measurements of Lattice Compression of Al, Si and Al-Si Alloys by High Pressure X-Ray Diffractometry  

Microsoft Academic Search

By making use of a cubic anvil press equipped with a rotating-target type X-ray generator and a goniometer, lattice compression in Al, Si and Al-Si alloys was precisely measured up to 90 kbar. The experimental precision was greatly improved by newly-devised treatments such as correctioning for off-centering of a sample and for peak shifts due to stacking faults, and the

Masafumi Senoo; Hisao Mii; Ikuya Fujishiro; Takao Fujikawa

1976-01-01

326

Precision Measurement of the Negative Pion Mass and the Experimental Verification of the Klein-Gordon Equation.  

NASA Astrophysics Data System (ADS)

A new precision measurement of the negative pion mass was. obtained by detecting the pionic x-rays of titanium (5g-4f) and. phosphorus (4f-3d) with a bent crystal spectrometer (139567 (+OR-). 1.00 keV/c('2)). The improvement in precision results from. improvements in the fractional energy resolution ((DELTA)E/E) by a factor. of four and in the signal-to-background ratio. High intensity sources. of pionic x-rays were generated by placing the titanium and. phosphorus targets adjacent to a copper pion production target in. the external 550-MeV proton beam of the Nevis Synchrocyclotron. The energy difference between the 5g - 4f and 5f - 4d transitions in. pionic titanium was also determined (87.3 (+OR -) 1.7 eV). This compares. well with the prediction of the Klein-Gordon equation (87.3 (+OR-) 1.0). to order (Z(alpha)/n)('4). In addition, in conjunction with measurements of. the muon momentum in pion decay at rest, a new upper limit of the. muon neutrino mass is determined (m(,(nu)(,(mu))) (LESSTHEQ) 0.52 MeV/c('2)). *Research supported by the National Science Foundation, NSF PHY 80-25317.

Delker, Lynn Magolnick

327

High-precision eigenvalues for the 1s2p /sup 1/P and /sup 3/P states of helium  

SciTech Connect

The double basis set method in Hylleraas coordinates described previously (G. W. F. Drake, Nucl. Instrum. Methods B31, 7 (1988)) is applied to the calculation of high-precision eigenvalues for the 1s2p /sup 1/P and /sup 3/P states of helium. Convergence to a few parts in 10/sup 14/ is obtained for the nonrelativistic energies. The new wave functions are used to calculate mass-polarization, relativistic, relativistic reduced mass, and quantum-electrodynamic corrections. A comparison of the P-state energies, together with the previously calculated S- and D-state energies, with the experimental energy levels tabulated by Martin (Phys. Rev A 36, 3575 (1987)) yields well-defined discrepancies of the order of 0.001 cm/sup -1/, which can be attributed to higher-order relativistic and quantum-electrodynamic effects.

Drake, G.W.F.; Makowski, A.J.

1988-10-01

328

High-precision optical fiber liquid-level sensor based on a sensitive and extrinsic Fabry-Perot interferometric cavity  

NASA Astrophysics Data System (ADS)

A novel intensity-based optical fiber liquid-level sensor based on a sensitive and extrinsic Fabry-Perot (F-P) interferometric cavity is described in this paper. The novel sensing schemes combines the advantages of both interferometry sensors and intensity-based sensors. The sensor operates on a single fiber F-P interferometric cavity with a DFB-LD light source. The elastic silicon slice replaces conventional reflected multimode optical fiber in extrinsic optical fiber F-P sensor as sensing element. Several steps have been taken to eliminate or restrain temperature effect influencing on the sensing system. Experimental results indicate a precision as high as 1.2mm of a full scale 3.5m (water) is obtained. The optimized sensor can be used in explosive and flammable environment to measure liquid-level continuously and accurately.

Lü, Tao; Liu, Desen

2007-01-01

329

Highly precise micro-retroreflector array fabricated by the LIGA process and its application as tapped delay line filter.  

PubMed

We report on the fabrication of a one-dimensional micro-retroreflector array with a pitch of 100 ?m. The array was fabricated by x-ray lithography and the lithographie, galvanik und abformung (LIGA) process in a 1 mm thick poly(methyl methacrylate) (PMMA) layer and subsequently covered with Au. The area of the array is 1 mm×10 mm. The high precision of the LIGA-based fabrication process allows one to use the element in spectrometers. Here, it is suggested to apply it to the implementation of a transversal filter for femtosecond pulses. We present a theoretical description of the performance of the retroreflector array as a filtering device and show experimental results. PMID:22945143

Bohling, Michael; Seiler, Thomas; Wdowiak, Boguslaw; Jahns, Jürgen; Mohr, Jürgen; Börner, Martin

2012-09-01

330

High precision Y89(alpha,alpha)Y89 scattering at low energies  

Microsoft Academic Search

Elastic scattering cross sections of the Y89(alpha,alpha)Y89 reaction have been measured at energies Ec.m.=15.51 and 18.63 MeV. The high-precision data for the semimagic N=50 nucleus Y89 are used to derive a local potential and to evaluate the predictions of global and regional alpha-nucleus potentials. The variation of the elastic alpha-scattering cross sections along the N=50 isotonic chain is investigated by

G. G. Kiss; P. Mohr; Zs. Fülöp; D. Galaviz; Gy. Gyürky; Z. Elekes; E. Somorjai; A. Kretschmer; K. Sonnabend; A. Zilges; M. Avrigeanu

2009-01-01

331

Information extraction as a basis for high-precision text classification  

Microsoft Academic Search

We describe an approach to text classification that\\u000a represents a compromise between traditional word-based\\u000a techniques and in-depth natural language processing. Our\\u000a approach uses a natural language processing task called\\u000a information extraction as a basis for high-precision text\\u000a classification. We present three algorithms that use\\u000a varying amounts of extracted information to classify\\u000a texts. The relevancy signatures algorithm uses linguistic\\u000a phrases, the

Ellen Riloff; Wendy Lehnert

1994-01-01

332

Design of a fast and high-precision polygonal scanner for HDTV  

NASA Astrophysics Data System (ADS)

With the continuing development of laser-display-technology, a new possibility for the production high level image projection is forwarded and with it the beginning of a new era in television: TV picture formats previously thought impossible, the sharpness, color intensity and unsurpassed resolution of which make the dream of home cinema a reality. The key to this experience is visible laser light in red, green and blue, projected on a screen with the aid of horizontal and vertical deflection units. In this paper, a primarily horizontal deflection system in the form of a rotating polygonal scanner is described. The design of this scanner assembly combines a double spherical air bearing with an integrated polygonal mirror for deflection and a high torque inside drive for quickly reaching high rotation. The Fraunhofer Institute of Applied Optics and Precision Engineering (IOF Jena) develops, from conception to assembled prototype, new self-acting precision bearing systems. This new scanner solution developed out of IOF's previous developments resulting in the first ever sealed, minimal-maintenance, self- acting bearing.

Risse, Stefan; Guyenot, Volker

1997-07-01

333

Diode laser-based sensor for high precision measurements of ambient CO2 in network applications  

NASA Astrophysics Data System (ADS)

The increasing need for better spatial and temporal measurements of greenhouse gases, especially CO2, to support global climate change modeling is driving the expansion of monitoring networks. Currently, networks making ambient CO2 measurements use environmentally stabilized sensors based on non-dispersive infrared absorption spectroscopy. To expand both measurement capability and coverage, much work is underway to develop highly accurate, reliable yet economical sensors for the greenhouse gases. The US Department of Energy has created specifications for a new sensor that has high performance but at a cost that permits widespread deployment. We report on a sensor designed to meet this need. We have demonstrated a compact, automated, high precision sensor for ambient CO2 that offers good performance in an economical package. The sensor is a near-IR diode laser-based absorption spectrometer operating near 2 ?m and using Integrated Cavity Output Spectroscopy (ICOS). Field demonstrations were carried out at both the UNH/AirMap Thompson Farm Observatory and the NOAA Boulder Atmospheric Observatory. The sensor has a demonstrated precision of between 0.090 and 0.125 ppmv for a 30 sec acquisition, or 1 part in 3000 to 4000.

Sonnenfroh, D.; Parameswaran, K.

2011-02-01

334

Precision data from LEP  

SciTech Connect

This conference report summarizes recent experimental progress on precise electroweak tests at the e{sup +}e{sup -} collider LEP. These data provide primarily a test of the Z propagator and the Zf{bar f} vertex. However, by imposing certain assumptions on the structure of the underlying theory, they also constrain vector boson self interactions. We review briefly new results concerning the Z line shape, polarization asymmetries and electroweak measurements with heavy quarks. We discuss the consistency of LEP high precision electroweak measurements within themselves with those from other experiments and with the Standard Model. {copyright} 1995 {ital American Institute of Physics.}

Schaile, D. [CERN, CH1211 Geneva (Switzerland)

1995-11-01

335

Active focal zone sharpening for high-precision treatment using histotripsy.  

PubMed

The goal of this study is to develop a focal zone sharpening strategy that produces more precise lesions for pulsed cavitational ultrasound therapy, or histotripsy. Precise and well-confined lesions were produced by locally suppressing cavitation in the periphery of the treatment focus without affecting cavitation in the center. The local suppression of cavitation was achieved using cavitation nuclei preconditioning pulses to actively control cavitation in the periphery of the focus. A 1-MHz 513-element therapeutic array was used to generate both the therapy and the nuclei preconditioning pulses. For therapy, 10-cycle bursts at 100-Hz pulse repetition frequency with P-/P+ pressure of 21/76 MPa were delivered to the geometric focus of the therapeutic array. For nuclei preconditioning, a different pulse was delivered to an annular region immediately surrounding the focus before each therapy pulse. A parametric study on the effective pressure, pulse duration, and delivery time of the preconditioning pulse was conducted in red blood cell-gel phantoms, where cavitational damage was indicated by the color change resulting from local cell lysis. Results showed that a short-duration (20 ?s) preconditioning pulse at a medium pressure (P-/P+ pressure of 7.2/13.6 MPa) delivered shortly before (30 ?s) the therapy pulse substantially suppressed the peripheral damage by 77 ± 13% while complete fractionation in the focal center was maintained. High-speed imaging of the bubble cloud showed a substantial decrease in the maximum width of the bubble cloud by 48 ± 24% using focal zone sharpening. Experiments in ex vivo livers confirmed that highly confined lesions were produced in real tissues as well as in the phantoms. This study demonstrated the feasibility of active focal zone sharpening using cavitation nuclei preconditioning, allowing for increased treatment precision compared with the natural focal width of the therapy transducer. PMID:21342816

Wang, Tzu-Yin; Xu, Zhen; Hall, Timothy; Fowlkes, J; Roberts, William; Cain, Charles

2011-02-01

336

Active Focal Zone Sharpening for High-Precision Treatment Using Histotripsy  

PubMed Central

The goal of this study is to develop a focal zone sharpening strategy that produces more precise lesions for pulsed cavitational ultrasound therapy, or histotripsy. Precise and well-confined lesions were produced by locally suppressing cavitation in the periphery of the treatment focus without affecting cavitation in the center. The local suppression of cavitation was achieved using cavitation nuclei preconditioning pulses to actively control cavitation in the periphery of the focus. A 1-MHz 513-element therapeutic array was used to generate both the therapy and the nuclei preconditioning pulses. For therapy, 10-cycle bursts at 100-Hz pulse repetition frequency with P?/P+ pressure of 21/76 MPa were delivered to the geometric focus of the therapeutic array. For nuclei preconditioning, a different pulse was delivered to an annular region immediately surrounding the focus before each therapy pulse. A parametric study on the effective pressure, pulse duration, and delivery time of the preconditioning pulse was conducted in red blood cell-gel phantoms, where cavitational damage was indicated by the color change resulting from local cell lysis. Results showed that a short-duration (20 µs) preconditioning pulse at a medium pressure (P?/P+ pressure of 7.2/13.6 MPa) delivered shortly before (30 µs) the therapy pulse substantially suppressed the peripheral damage by 77 ± 13% while complete fractionation in the focal center was maintained. High-speed imaging of the bubble cloud showed a substantial decrease in the maximum width of the bubble cloud by 48 ± 24% using focal zone sharpening. Experiments in ex vivo livers confirmed that highly confined lesions were produced in real tissues as well as in the phantoms. This study demonstrated the feasibility of active focal zone sharpening using cavitation nuclei preconditioning, allowing for increased treatment precision compared with the natural focal width of the therapy transducer.

Wang, Tzu-Yin; Xu, Zhen; Hall, Timothy L.; Fowlkes, J. Brian; Roberts, William W.; Cain, Charles A.

2011-01-01

337

Optical test bench for high precision metrology and alignment of zoom sub-assembly components  

NASA Astrophysics Data System (ADS)

Thales Angénieux (TAGX) designs and manufactures zoom lens assemblies for cinema applications. These objectives are made of mobile lens assemblies. These need to be precisely characterized to detect alignment, polishing or glass index homogeneity errors, which amplitude may range to a few hundreds of nanometers. However these assemblies are highly aberrated with mainly spherical aberration (>30 ?m PV). PHASICS and TAGX developed a solution based on the use of a PHASICS SID4HR wave front sensor. This is based on quadri-wave lateral shearing interferometry, a technology known for its high dynamic range. A 100-mm diameter He:Ne source illuminates the lens assembly entrance pupil. The transmitted wave front is then directly measured by the SID4- HR. The measured wave front (WFmeas) is then compared to a simulation from the lens sub-assembly optical design (WFdesign). We obtain a residual wave front error (WFmanufactured), which reveals lens imperfections due to its manufacturing. WFmeas=WFdesign+(WFEradius+WFEglass+WFEpolish)=WF design + WFmanufactured The optical test bench was designed so that this residual wave front is measured with a precision below 100 nm PV. The measurement of fast F-Number lenses (F/2) with aberrations up to 30 ?m, with a precision of 100 nm PV was demonstrated. This bench detects mismatches in sub-assemblies before the final integration step in the zoom. Pre-alignment is also performed in order to overpass the mechanical tolerances. This facilitates the completed zoom alignment. In final, productivity gains are expected due to alignment and mounting time savings.

Leprêtre, F.; Levillain, E.; Wattellier, B.; Delage, P.; Brahmi, D.; Gascon, A.

2013-09-01

338

A high precision dual feedback pump for unsteady perfusion of small organs.  

PubMed

A dynamic pump system is described for perfusion of small organs with whole blood. The pump system was designed with the following aims: Very low flowrates to perfuse single organs in small rodents; high dynamic response for pressure or flow to permit experimenting with a harmonic signal at frequencies up to 20 Hz or by way of sharp step transients in less than 10 msec; high precision to allow detection of fine physiological details, and minimum blood cell trauma or cell activation by use of a piston principle. Representative pressure-flow curves are shown for the rat gracilis muscle after vasodilation. The curves are highly reproducible and serve as a complimentary dataset for microvascular observations in the same organ. PMID:2735584

Sutton, D W; Mead, E H; Schmid-Schönbein, G W

1989-01-01

339

A numerical method for determining highly precise electron energy distribution functions from Langmuir probe characteristics  

SciTech Connect

Electron energy distribution functions (EEDFs) were determined from probe characteristics using a numerical ac superimposed method with a distortion correction of high derivative terms by varying amplitude of a sinusoidal perturbation voltage superimposed onto the dc sweep voltage, depending on the related electron energy. Low amplitude perturbation applied around the plasma potential represented the low energy peak of the EEDF exactly, and high amplitude perturbation applied around the floating potential was effective to suppress noise or distortion of the probe characteristic, which is fatal to the tail electron distribution. When a small random noise was imposed over the stabilized prove characteristic, the numerical differentiation method was not suitable to determine the EEDF, while the numerical ac superimposed method was able to obtain a highly precise EEDF.

Bang, Jin-Young; Chung, Chin-Wook [Department of Electrical Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)

2010-12-15

340

MEMS - Frequency Agile High Precision Ranging under the Dual Use Applications Program (DUAP)  

NASA Astrophysics Data System (ADS)

The objective of this program was laboratory demonstration of a low cost, jamming resistant, precision ranging system (radar) for proximity fuze and short-range measurement systems. Two approaches were envisioned: (1) The baseline-a baseband system directly radiating and detecting a random sequence of short pulses and (2) A higher risk design based on a transmitter using high-speed modulation of a micro-electromechanical (MEM) oscillator to avoid low frequency antenna radiation requirements. Size constraints drive the design toward small, single-chip monocycle pulse radar implemented in CMOS (Complementary Metal Oxide Semiconductors). This device with two external capacitors, a battery and a miniature antenna for the baseline approach is described in Figure 1-1. Triggering ranges from several inches to more than 6feet were demonstrated. Fabrication of MEM components on gallium arsenide for the second approach will require additional work. While CMOS technology is almost ideal for the long time-constant, multiple pulse integration circuits in the precision ranging receiver and most of the transmitter circuits, it is insufficient for submunition sensor final output amplifiers. The issue is the small size of the submunition antenna. Either step recovery diode circuit or higher performance output transistors are needed to generate the high frequency spectrum required for efficient radiation from these antennas. Using a 0.5-micron BiCMOS/Si(3e process, recently available for prototyping at MOSIS,' all of the required CMOS and faster output devices could be implemented with trivial modifications of the existing circuits.

Bauhahn, Paul

2001-12-01

341

A High Precision Position Sensor Design and Its Signal Processing Algorithm for a Maglev Train  

PubMed Central

High precision positioning technology for a kind of high speed maglev train with an electromagnetic suspension (EMS) system is studied. At first, the basic structure and functions of the position sensor are introduced and some key techniques to enhance the positioning precision are designed. Then, in order to further improve the positioning signal quality and the fault-tolerant ability of the sensor, a new kind of discrete-time tracking differentiator (TD) is proposed based on nonlinear optimal control theory. This new TD has good filtering and differentiating performances and a small calculation load. It is suitable for real-time signal processing. The stability, convergence property and frequency characteristics of the TD are studied and analyzed thoroughly. The delay constant of the TD is figured out and an effective time delay compensation algorithm is proposed. Based on the TD technology, a filtering process is introduced in to improve the positioning signal waveform when the sensor is under bad working conditions, and a two-sensor switching algorithm is designed to eliminate the positioning errors caused by the joint gaps of the long stator. The effectiveness and stability of the sensor and its signal processing algorithms are proved by the experiments on a test train during a long-term test run.

Xue, Song; Long, Zhiqiang; He, Ning; Chang, Wensen

2012-01-01

342

Opportunities for High Precision Photometric Measurements of Variable Stars: Kepler Guest Investigator Program  

NASA Astrophysics Data System (ADS)

The Kepler Mission is designed to detect terrestrial planets by monitoring the flux of more than 100,000 dwarf stars for a period of four years at a cadence of 4/hour. During the early portion of the mission when the telemetry rate is high, approximately 170,000 stars will be monitored. The photometric precision for 6.5-hour integration periods will be 20 ppm to 89 ppm for 12th to 15th magnitude stars, respectively. Prior to the launch, multiband photometry of all target stars will be made to estimate spectral type, brightness temperature, and luminosity class. To the extent possible, the initial target list will exclude evolved stars and those known to be variable. Sometime after the first year, the target list will be trimmed by removing those stars found to be too variable to detect planets unless requests for continued observations are received from the stellar astrophysics community. A Guest Observer program is being developed to accommodate those wishing to observe targets in the 140 square degree Kepler field of view centered at RA 19h 22m 40s, Dec +44° 30'. A webtool is available to assess whether your favorite object is on the Kepler detectors. This program represents an unprecedented opportunity to obtain extremely high precision photometry over very long (typically 3 month) intervals with almost continuous coverage. At any given time there will be 2000-3000 Guest Observer targets (a few of which can be observed with a one-minute cadence).

Borucki, W. J.; Koch, D. G.; Basri, G. S.; Latham, D. W.; Howell, S. B.

2004-12-01

343

Diode Laser-based Sensor for High Precision Measurements of Ambient CO2  

NASA Astrophysics Data System (ADS)

We report on the development of a new, high precision sensor for monitoring ambient CO2. This economical, robust, autonomous CO2 sensor is intended for widespread deployment in networks. We have developed a tunable diode laser-based absorption spectrometer, operating at a wavelength of 2 "Ým, which utilizes Integrated Cavity Output Spectroscopy (ICOS) to create an optical pathlength of 60 m in a physical pathlength of 20 cm. The sensor also uses Wavelength Modulation Spectroscopy for high sensitivity detection. We have achieved a precision of better than 1 part in 3000 for the dry air mixing ratio of CO2 for a 1 minute averaging period. The sensor design ensures a measurement cell having a small sample volume, which decreases the consumption of calibration gases. We also use an integrated dedicated microprocessor-based controller and signal processing electronics to achieve a small footprint. The sensor measures 20 x 43 x 56 cm and weighs 15 kg. The prototype was demonstrated at the University of New Hampshire's Atmospheric Observatory at Thompson Farm, in Durham, NH during June and July 2008. It was successfully intercompared with an NDIR sensor and operated automatically around the clock for 6 weeks. It was also intercompared with the NOAA NDIR sensor at the Boulder Atmospheric Observatory in Erie, CO in September 2008.

Sonnenfroh, D. M.; Parameswaran, K.; Varner, R.

2008-12-01

344

High-precision figured thin supermirror substrates for multiple neutron focusing device  

NASA Astrophysics Data System (ADS)

An aspherical supermirror is one of the most useful neutron-focusing optics. We aim to develop multiple aspherical supermirror devices using high-precision figured aspherical focusing supermirrors to focus neutron beams with high intensities, because multiple mirrors collect a very large beam divergence. Thin mirrors with a millimeter thickness are required to minimize the absorption loss of incident neutron beams since the thickness of a mirror shadows the reflective area of the other mirrors. However, it is difficult to fabricate thin mirror substrates with a form accuracy of sub-micrometer level by conventional machining. Conventional machining deforms a substrate by machining force and spring back after machining causes figure error. Furthermore the deposition of supermirrors deforms the mirror substrate by film stress. Thus, we developed a new process of fabricating a precise millimeter-thick elliptical supermirror. This process consists of noncontact figuring by the numerically controlled local wet etching technique and the ion beam sputter deposition of NiC/Ti multilayers on both sides of the mirror substrate to compensate for film stress. In this paper, we report on the fabrication results and focusing performance of elliptical supermirrors with a thickness of 1.5 mm.

Nagano, M.; Yamaga, F.; Yamazaki, D.; Maruyama, R.; Hayashida, H.; Soyama, K.; Yamamura, K.

2012-02-01

345

A new polishing process for large-aperture and high-precision aspheric surface  

NASA Astrophysics Data System (ADS)

The high-precision aspheric surface is hard to be achieved due to the mid-spatial frequency error in the finishing step. The influence of mid-spatial frequency error is studied through the simulations and experiments. In this paper, a new polishing process based on magnetorheological finishing (MRF), smooth polishing (SP) and ion beam figuring (IBF) is proposed. A 400mm aperture parabolic surface is polished with this new process. The smooth polishing (SP) is applied after rough machining to control the MSF error. In the middle finishing step, most of low-spatial frequency error is removed by MRF rapidly, then the mid-spatial frequency error is restricted by SP, finally ion beam figuring is used to finish the surface. The surface accuracy is improved from the initial 37.691nm (rms, 95% aperture) to the final 4.195nm. The results show that the new polishing process is effective to manufacture large-aperture and high-precision aspheric surface.

Nie, Xuqing; Li, Shengyi; Dai, Yifan; Song, Ci

2013-07-01

346

Highly Precise and Developmentally Programmed Genome Assembly in Paramecium Requires Ligase IV-Dependent End Joining  

PubMed Central

During the sexual cycle of the ciliate Paramecium, assembly of the somatic genome includes the precise excision of tens of thousands of short, non-coding germline sequences (Internal Eliminated Sequences or IESs), each one flanked by two TA dinucleotides. It has been reported previously that these genome rearrangements are initiated by the introduction of developmentally programmed DNA double-strand breaks (DSBs), which depend on the domesticated transposase PiggyMac. These DSBs all exhibit a characteristic geometry, with 4-base 5? overhangs centered on the conserved TA, and may readily align and undergo ligation with minimal processing. However, the molecular steps and actors involved in the final and precise assembly of somatic genes have remained unknown. We demonstrate here that Ligase IV and Xrcc4p, core components of the non-homologous end-joining pathway (NHEJ), are required both for the repair of IES excision sites and for the circularization of excised IESs. The transcription of LIG4 and XRCC4 is induced early during the sexual cycle and a Lig4p-GFP fusion protein accumulates in the developing somatic nucleus by the time IES excision takes place. RNAi–mediated silencing of either gene results in the persistence of free broken DNA ends, apparently protected against extensive resection. At the nucleotide level, controlled removal of the 5?-terminal nucleotide occurs normally in LIG4-silenced cells, while nucleotide addition to the 3? ends of the breaks is blocked, together with the final joining step, indicative of a coupling between NHEJ polymerase and ligase activities. Taken together, our data indicate that IES excision is a “cut-and-close” mechanism, which involves the introduction of initiating double-strand cleavages at both ends of each IES, followed by DSB repair via highly precise end joining. This work broadens our current view on how the cellular NHEJ pathway has cooperated with domesticated transposases for the emergence of new mechanisms involved in genome dynamics.

Marmignon, Antoine; Ku, Michael; Silve, Aude; Meyer, Eric; Forney, James D.; Malinsky, Sophie; Betermier, Mireille

2011-01-01

347

Precise method for modifying birefringence of stress-induced high-birefringence fiber.  

PubMed

A precise method for modifying the birefringence of stress-induced high-birefringence (Hi-Bi) fiber is demonstrated by side polishing a Panda-type fiber with a maximum polished length of at least 14 cm. The polishing depth is controlled with an accuracy of 0.1 microm by piezoelectric ceramic microdisplacement. The accuracy of the birefringence is of the order of 10(-6). This method allows high-quality Hi-Bi fiber segments to be conveniently implemented with low loss at any desired birefringence between 3.17 x 10(-4) and 7.5 x 10(-5) in our experiment from one stress-induced Hi-Bi fiber and without changing the directions of the stress axes. The finite-element method is used to simulate the procedure, and the numerical results agree with the experiment. PMID:20808385

Zhao, Ruifeng; Pei, Li; Dong, Xiaowei; Ning, Tigang; Li, Zhuoxuan; Jiang, Weiwei; Fan, Linyong; Zhang, Chenfang

2010-09-01

348

High-precision soft x-ray polarimeter at Diamond Light Source.  

PubMed

The development and performance of a high-precision polarimeter for the polarization analysis in the soft x-ray region is presented. This versatile, high-vacuum compatible instrument is supported on a hexapod to simplify the alignment with a resolution less than 5 ?rad, and can be moved with its own independent control system easily between different beamlines and synchrotron facilities. The polarimeter can also be used for the characterization of reflection and transmission properties of optical elements. A W/B(4)C multilayer phase retarder was used to characterize the polarization state up to 1200 eV. A fast and accurate alignment procedure was developed, and complete polarization analysis of the APPLE II undulator at 712 eV has been performed. PMID:22225209

Wang, H; Dhesi, S S; Maccherozzi, F; Cavill, S; Shepherd, E; Yuan, F; Deshmukh, R; Scott, S; van der Laan, G; Sawhney, K J S

2011-12-01

349

Note: High precision angle generator using multiple ultrasonic motors and a self-calibratable encoder  

NASA Astrophysics Data System (ADS)

We present an angle generator with high resolution and accuracy, which uses multiple ultrasonic motors and a self-calibratable encoder. A cylindrical air bearing guides a rotational motion, and the ultrasonic motors achieve high resolution over the full circle range with a simple configuration. The self-calibratable encoder can compensate the scale error of a divided circle (signal period: 20'') effectively by applying the equal-division-averaged method. The angle generator configures a position feedback control loop using the readout of the encoder. By combining the ac and dc operation mode, the angle generator produced stepwise angular motion with 0.005'' resolution. We also evaluated the performance of the angle generator using a precision angle encoder and an autocollimator. The expanded uncertainty (k = 2) in the angle generation was estimated less than 0.03'', which included the calibrated scale error and the nonlinearity error.

Kim, Jong-Ahn; Kim, Jae Wan; Kang, Chu-Shik; Jin, Jonghan; Bong Eom, Tae

2011-11-01

350

Flow-Based Systems for Rapid and High-Precision Enzyme Kinetics Studies  

PubMed Central

Enzyme kinetics studies normally focus on the initial rate of enzymatic reaction. However, the manual operation of steps of the conventional enzyme kinetics method has some drawbacks. Errors can result from the imprecise time control and time necessary for manual changing the reaction cuvettes into and out of the detector. By using the automatic flow-based analytical systems, enzyme kinetics studies can be carried out at real-time initial rate avoiding the potential errors inherent in manual operation. Flow-based systems have been developed to provide rapid, low-volume, and high-precision analyses that effectively replace the many tedious and high volume requirements of conventional wet chemistry analyses. This article presents various arrangements of flow-based techniques and their potential use in future enzyme kinetics applications.

Hartwell, Supaporn Kradtap; Grudpan, Kate

2012-01-01

351

A high-precision cryogenically-cooled crystal monochromator for the APS diagnostics beamline  

SciTech Connect

A high-precision cryogenically-cooled crystal monochromator has been developed for the APS diagnostics beamline. The design permits simultaneous measurements of the particle beam size and divergence. It provides for a large rotation angle, {minus}15{degree} to 180{degree}, with a resolution of 0.0005{degree}. The roll angle of the crystal can be adjusted by up to {+-}3{degree} with a resolution of 0.0001{degree}. A vertical translational stage, with a stroke of {+-}25 mm and resolution of 8 {micro}m, is provided to enable using different parts of the same crystal or to retract the crystal from the beam path. The modular design will allow optimization of cooling schemes to minimize thermal distortions of the crystal under high heat loads.

Rotela, E.; Yang, B.; Sharma, s.; Barcikowski, A.

2000-07-24

352

High Precision Tune and Coupling Feedback and Beam Transfer Function Measurements in RHIC  

SciTech Connect

Precision measurement and control of the betatron tunes and betatron coupling in the Relativistic Heavy Ion Collider (RHIC) are required for establishing and maintaining both good operating conditions and, particularly during the ramp to high beam energies, high proton beam polarization. While the proof-of-principle for simultaneous tune and coupling feedback was successfully demonstrated earlier, routine application of these systems has only become possible recently. Following numerous modifications for improved measurement resolution and feedback control, the time required to establish full-energy beams with the betatron tunes and coupling regulated by feedback was reduced from several weeks to a few hours. A summary of these improvements, select measurements benefitting from the improved resolution and a review of system performance are the subject of this report.

Minty, M.; Curcio, A.; Dawson, C.; Degen, C.; Luo, Y.; Marr, G.; Martin, B.; Marusic, A.; Mernick, K.; Oddo, P.; Russo, T.; Schoefer, V.; Schroeder, R.; Schultheiss, C.; Wilinski, M.

2010-05-23

353

Design and Calibration of a High-Precision Density Gauge for Firn and Ice Cores  

NASA Astrophysics Data System (ADS)

The Maine Automated Density Gauge Experiment (MADGE) is a field deployable gamma-ray density gauging instrument designed to provide high resolution (3.3 mm) and high precision (±0.004 g cm-3) density profiles of polar firn and ice cores at a typical throughput of 1.5 m h-1. The resulting density profiles are important in ice sheet mass balance and paleoclimate studies, as well as the modeling electromagnetic wave propagation in firn and ice for remote sensing and ground penetrating radar applications. This study describes the design (optimal gamma-ray energy selection, measurement uncertainty analysis, dead-time corrections) and calibration (mass-attenuation coefficient and absolute density calibrations) of the instrument, and discusses the results of additional experiments to verify the calculated measurement uncertainty. Data collected from firn cores drilled on the recent 2006-2007 U.S. Internation Trans-Antarctic Scientific Expedition are also shown and discussed.

Breton, Daniel; Hamilton, Gordon

2009-10-01

354

The Generation of Higher-order Laguerre-Gauss Optical Beams for High-precision Interferometry.  

PubMed

Thermal noise in high-reflectivity mirrors is a major impediment for several types of high-precision interferometric experiments that aim to reach the standard quantum limit or to cool mechanical systems to their quantum ground state. This is for example the case of future gravitational wave observatories, whose sensitivity to gravitational wave signals is expected to be limited in the most sensitive frequency band, by atomic vibration of their mirror masses. One promising approach being pursued to overcome this limitation is to employ higher-order Laguerre-Gauss (LG) optical beams in place of the conventionally used fundamental mode. Owing to their more homogeneous light intensity distribution these beams average more effectively over the thermally driven fluctuations of the mirror surface, which in turn reduces the uncertainty in the mirror position sensed by the laser light. We demonstrate a promising method to generate higher-order LG beams by shaping a fundamental Gaussian beam with the help of diffractive optical elements. We show that with conventional sensing and control techniques that are known for stabilizing fundamental laser beams, higher-order LG modes can be purified and stabilized just as well at a comparably high level. A set of diagnostic tools allows us to control and tailor the properties of generated LG beams. This enabled us to produce an LG beam with the highest purity reported to date. The demonstrated compatibility of higher-order LG modes with standard interferometry techniques and with the use of standard spherical optics makes them an ideal candidate for application in a future generation of high-precision interferometry. PMID:23962813

Carbone, Ludovico; Fulda, Paul; Bond, Charlotte; Brueckner, Frank; Brown, Daniel; Wang, Mengyao; Lodhia, Deepali; Palmer, Rebecca; Freise, Andreas

2013-08-12

355

Continuous online field deployable high precision and high resolution water isotope analysis from ice cores  

Microsoft Academic Search

One of the most important features of ice cores as climate and atmospheric paleoarchives is their potential for high temporal resolution. The measurement of chemical impurities in ice cores that fully exploits this high resolution has become standard with the advent of Continuous Flow Analysis (CFA) from continuously melted ice core segments, often performed in the field. Meanwhile, the measurement

Vasileios Gkinis; Trevor Popp; Sigfus Johnsen; Thomas Blunier; Christopher Stowasser; Ernesto Kettner

2010-01-01

356

A complex programmable logic device-based high-precision electrical capacitance tomography system  

NASA Astrophysics Data System (ADS)

In this paper, a high-precision measurement system for electrical capacitance tomography (ECT) is presented. A low-cost complex programmable logic device (CPLD) is employed to accomplish logic control, signal generation, data acquisition, digital demodulation and communication with the aid of external components. By adopting a simple digital demodulator recently developed by the authors, the demodulation to ac signals becomes rather simple and resource-saving. A double-T-switches configuration is developed to improve the precision and lower the limit of multi-channel capacitance measurement. A capacitance network is constructed for system calibration. A square ECT sensor with 16 electrodes is constructed to test the practical performance of the measurement system. With a data acquisition rate of 185 frame s-1, the signal-to-noise ratio and standard deviation of capacitance measurement can reach up to 70 dB and 0.09 fF, respectively. Image reconstruction experiment has validated the CPLD-based ECT system.

Zhou, Haili; Xu, Lijun; Cao, Zhang; Liu, XiaoLei; Liu, Shi

2013-07-01

357

Precision of navigated and conventional open-wedge high tibial osteotomy in a cadaver study  

PubMed Central

High tibial osteotomy (HTO) is an established treatment option for isolated medial osteoarthritis in young and active patients. One important factor for success of this procedure is the degree of correction of the weight-bearing line. Computer-assisted navigation systems are believed to improve the precision of axis correction through intraoperative real-time monitoring. This study investigates the precision of correction of the weight-bearing line in open-wedge HTO with and without a navigation system. Nineteen legs of well-preserved human cadaver were randomly assigned to navigated (n = 10) or conventional (n = 9) HTO. In order to achieve a sufficient amount of correction in all legs the weight-bearing line was aimed at 80 percent of the width of the tibial plateau. The mean deviation of the weight-bearing line from the desired 80 percent was 1 percent in the navigated and 8.6 percent in the conventional operated legs (p = 0.002). The weight-bearing line of all navigated but only 5 of the 9 conventional operated legs was within a ± 5 percent tolerance level (p = 0.33). Navigated open-wedge HTO achieved better correction of the weight-bearing line than the conventional method in human cadaver legs. Future studies have to prove this advantage in a clinical setting and it's effect on patient outcome.

2010-01-01

358

High-precision radiocarbon dating and historical biblical archaeology in southern Jordan  

PubMed Central

Recent excavations and high-precision radiocarbon dating from the largest Iron Age (IA, ca. 1200–500 BCE) copper production center in the southern Levant demonstrate major smelting activities in the region of biblical Edom (southern Jordan) during the 10th and 9th centuries BCE. Stratified radiocarbon samples and artifacts were recorded with precise digital surveying tools linked to a geographic information system developed to control on-site spatial analyses of archaeological finds and model data with innovative visualization tools. The new radiocarbon dates push back by 2 centuries the accepted IA chronology of Edom. Data from Khirbat en-Nahas, and the nearby site of Rujm Hamra Ifdan, demonstrate the centrality of industrial-scale metal production during those centuries traditionally linked closely to political events in Edom's 10th century BCE neighbor ancient Israel. Consequently, the rise of IA Edom is linked to the power vacuum created by the collapse of Late Bronze Age (LB, ca. 1300 BCE) civilizations and the disintegration of the LB Cypriot copper monopoly that dominated the eastern Mediterranean. The methodologies applied to the historical IA archaeology of the Levant have implications for other parts of the world where sacred and historical texts interface with the material record.

Levy, Thomas E.; Higham, Thomas; Bronk Ramsey, Christopher; Smith, Neil G.; Ben-Yosef, Erez; Robinson, Mark; Munger, Stefan; Knabb, Kyle; Schulze, Jurgen P.; Najjar, Mohammad; Tauxe, Lisa

2008-01-01

359

Quantifying Condition-Dependent Intracellular Protein Levels Enables High-Precision Fitness Estimates  

PubMed Central

Countless studies monitor the growth rate of microbial populations as a measure of fitness. However, an enormous gap separates growth-rate differences measurable in the laboratory from those that natural selection can distinguish efficiently. Taking advantage of the recent discovery that transcript and protein levels in budding yeast closely track growth rate, we explore the possibility that growth rate can be more sensitively inferred by monitoring the proteomic response to growth, rather than growth itself. We find a set of proteins whose levels, in aggregate, enable prediction of growth rate to a higher precision than direct measurements. However, we find little overlap between these proteins and those that closely track growth rate in other studies. These results suggest that, in yeast, the pathways that set the pace of cell division can differ depending on the growth-altering stimulus. Still, with proper validation, protein measurements can provide high-precision growth estimates that allow extension of phenotypic growth-based assays closer to the limits of evolutionary selection.

Geiler-Samerotte, Kerry A.; Hashimoto, Tatsunori; Dion, Michael F.; Budnik, Bogdan A.; Airoldi, Edoardo M.; Drummond, D. Allan

2013-01-01

360

High-precision laser beam shaping using binary-amplitude DLP spatial light modulators  

NASA Astrophysics Data System (ADS)

Laser beams with precisely controlled intensity profiles are essential for many areas of optics and optical physics. We create such beams from real-world lasers: quasi-Gaussian beams obtained directly from a laser and beam-expanding telescope without spatial filtering. Our application is to form optical standing-wave lattices for Bose-Einstein condensates in quantum emulators. This requires controlled amplitude and flat phase, and that the beam be free of temporal modulation from either pixel dithering or refresh cycles. We describe the development of the pattern design algorithms and demonstrate the performance of a high precision beam shaper to make flattop beams and other spatial profiles with similarly low spatial frequency content. The digital micromirror device (DMD) was imaged through a telescope containing a pinhole low-pass filter. An error diffusion algorithm was used to design the initial DMD pixel pattern based on the input beam profile. This pattern was iteratively refined based on output image measurements. We demonstrate forming a variety of beam profiles including flattop beams and beams with 1-D linear intensity variation, both with square and circular cross-sections. Produced beams had less than 0.25% root-mean-square (RMS) error with respect to the target profile and nearly flat phase.

Becker, Michael F.; Liang, Jinyang; Kohn, Rudolph N., Jr.; Heinzen, Daniel J.

2010-02-01

361

Precision measurements with highly charged ions at rest: The HITRAP project at GSI  

Microsoft Academic Search

A decelerator will be installed at GSI in order to provide and study bare heavy nuclei or heavy nuclei with only few electrons at very low energies or almost at rest. Stripping at relativistic energies will produce highly charged ions. After electron cooling and deceleration in the experimental storage ring the ions are extracted from the storage ring at 4?MeV\\/u

F. Herfurth; Th. Beier; L. Dahl; S. Eliseev; S. Heinz; O. Kester; C. Kozhuharov; G. Maero; W. Quint

2006-01-01

362

Closed tubes preparation of graphite for high-precision AMS radiocarbon analysis  

NASA Astrophysics Data System (ADS)

Radiocarbon dating is an established tool applied in Geochronology. Technical developments of Accelerator Mass Spectrometry AMS, which allow measurements of samples containing less than 1 mg of carbon, opened opportunities for new applications. Moreover, high resolution records of the past changes require high-resolution chronologies i.e. sampling for 14C dating. In result, the field of applications is rapidly expanding and number of radiocarbon analysis is growing rapidly. Nowadays dedicated 14C AMS machines have great capacity for analysis but in order to keep up with the demand for analysis and provide the results as fast as possible a very efficient way of sample preparation is required. Sample preparation for 14C AMS analysis consists of two steps: separation of relevant carbon from the sample material (removing contamination) and preparation of graphite for AMS analysis. The last step usually involves reaction of CO2 with H2, in the presence of metal catalyst (Fe or Co) of specific mesh size heated to 550-625°C, as originally suggested by Vogel et al. (1984). Various graphitization systems have been built in order to fulfil the requirement of sample quality needed for high-precision radiocarbon data. In the early 90ties another method has been proposed (Vogel 1992) and applied by few laboratories mainly for environmental or biomedical samples. This method uses TiH2 as a source of H2 and can be easily and flexibly applied to produce graphite. Sample of CO2 is frozen in to the tube containing pre-conditioned Zn/TiH2 and Fe catalyst. Torch sealed tubes are then placed in the stepwise heated oven at 500/550°C and left to react for several hours. The greatest problem is the lack of control of the reaction completeness and considerable fractionation. However, recently reported results (Xu et al. 2007) suggest that high precision dating using graphite produced in closed tubes might be possible. We will present results of radiocarbon dating of the set of standards and secondary IAEA standards to demonstrate to what level this method can be used for high precision radiocarbon dating. References Vogel JS. 1992. Rapid Production of Graphite without Contamination for Biomedical Ams. Radiocarbon 34: 344-350. Vogel JS, Southon JR, Nelson DE, and Brown TA. 1984. Performance of Catalytically Condensed Carbon for Use in Accelerator Mass-Spectrometry. Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms 233: 289-293. Xu X, Trumbore SE, Zheng S, Southon JR, McDuffee KE, Luttgen M, and Liu JC. 2007. Modifying a sealed tube zinc reduction method for preparation of AMS graphite targets: Reducing background and attaining high precision. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms Accelerator Mass Spectrometry - Proceedings of the Tenth International Conference on Accelerator Mass Spectrometry 259: 320-329.

Hajdas, I.; Michczynska, D.; Bonani, G.; Maurer, M.; Wacker, L.

2009-04-01

363

Velocity and abundance precisions for future high-resolution spectroscopic surveys: A study for 4MOST  

NASA Astrophysics Data System (ADS)

In preparation for future, large-scale, multi-object, high-resolution spectroscopic surveys of the Galaxy, we present a series of tests of the precision in radial velocity and chemical abundances that any such project can achieve at a 4 m class telescope. We briefly discuss a number of science cases that aim at studying the chemo-dynamical history of the major Galactic components (bulge, thin and thick disks, and halo) - either as a follow-up to the Gaia mission or on their own merits. Based on a large grid of synthetic spectra that cover the full range in stellar parameters of typical survey targets, we devise an optimal wavelength range and argue for a moderately high-resolution spectrograph. As a result, the kinematic precision is not limited by any of these factors, but will practically only suffer from systematic effects, easily reaching uncertainties <1 km s-1. Under realistic survey conditions (namely, considering stars brighter than r=16 mag with reasonable exposure times) we prefer an ideal resolving power of R˜20 000 on average, for an overall wavelength range (with a common two-arm spectrograph design) of [395;456.5] nm and [587;673] nm. We show for the first time on a general basis that it is possible to measure chemical abundance ratios to better than 0.1 dex for many species (Fe, Mg, Si, Ca, Ti, Na, Al, V, Cr, Mn, Co, Ni, Y, Ba, Nd, Eu) and to an accuracy of about 0.2 dex for other species such as Zr, La, and Sr. While our feasibility study was explicitly carried out for the 4MOST facility, the results can be readily applied to and used for any other conceptual design study for high-resolution spectrographs.

Caffau, E.; Koch, A.; Sbordone, L.; Sartoretti, P.; Hansen, C. J.; Royer, F.; Leclerc, N.; Bonifacio, P.; Christlieb, N.; Ludwig, H.-G.; Grebel, E. K.; de Jong, R. S.; Chiappini, C.; Walcher, J.; Mignot, S.; Feltzing, S.; Cohen, M.; Minchev, I.; Helmi, A.; Piffl, T.; Depagne, E.; Schnurr, O.

2013-03-01

364

Theoretical and experimental research on machine tool servo system for ultra-precision position compensation on CNC lathe  

Microsoft Academic Search

The theories and techniques for improving machining accuracy via position control of diamond tool's tip and raising resolution of cutting depth on precise CNC lathes have been extremely focused on. A new piezo-driven ultra-precision machine tool servo system is designed and tested to improve manufacturing accuracy of workpiece. The mathematical model of machine tool servo system is established and the

Zhichao Ma; Leilei Hu; Hongwei Zhao; Boda Wu; Zhenxing Peng; Xiaoqin Zhou; Hongguo Zhang; Shuai Zhu; Lifeng Xing; Huang Hu

2010-01-01

365

High precision series solutions of differential equations: Ordinary and regular singular points of second order ODEs  

NASA Astrophysics Data System (ADS)

A subroutine for a very-high-precision numerical solution of a class of ordinary differential equations is provided. For a given evaluation point and equation parameters the memory requirement scales linearly with precision P, and the number of algebraic operations scales roughly linearly with P when P becomes sufficiently large. We discuss results from extensive tests of the code, and how one, for a given evaluation point and equation parameters, may estimate precision loss and computing time in advance.Program summaryProgram title: seriesSolveOde1Catalogue identifier: AEMW_v1_0Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEMW_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 991No. of bytes in distributed program, including test data, etc.: 488116Distribution format: tar.gzProgramming language: C++Computer: PC’s or higher performance computers.Operating system: Linux and MacOSRAM: Few to many megabytes (problem dependent).Classification: 2.7, 4.3External routines: CLN — Class Library for Numbers [1] built with the GNU MP library [2], and GSL — GNU Scientific Library [3] (only for time measurements).Nature of problem:The differential equation -s2(d2dz2+1-?+-?-zddz+?+?-z2)?(z)+1z?n=0Nvnzn?(z)=0, is solved numerically to very high precision. The evaluation point z and some or all of the equation parameters may be complex numbers; some or all of them may be represented exactly in terms of rational numbers.Solution method: The solution ?(z), and optionally ??(z), is evaluated at the point z by executing the recursion A(z)=s-2(m+1+?-?+)(m+1+?-?-)?n=0NVn(z)A(z),?(z)=?(z)+A(z), to sufficiently large m. Here ? is either ?+ or ?-, and Vn(z)=vnz. The recursion is initialized by A(z)=?z?,for n=0,1,…,N?(z)=A0(z). Restrictions: No solution is computed if z=0, or s=0, or if ?=?- (assuming Re?+?Re?-) with ?+-?- an integer, except when ?+-?-=1 and v0=0 (i.e. when z is an ordinary point for z?(z)).Additional comments: The code of the main algorithm is in the file seriesSolveOde1.cc, which “#include” the file checkForBreakOde1.cc. These routines, and the programs using them, must “#include” the file seriesSolveOde1.cc.Running time: On a Linux PC that is a few years old, at y=10 to an accuracy of P=200 decimal digits, evaluating the ground state wavefunction of the anharmonic oscillator (with the eigenvalue known in advance); (cf. Eq. (6)) takes about 2 ms, and about 40 min at an accuracy of P=100000 decimal digits.References:[1] B. Haible and R.B. Kreckel, CLN — Class Library for Numbers, http://www.ginac.de/CLN/[2] T. Granlund and collaborators, GMP — The GNU Multiple Precision Arithmetic Library, http://gmplib.org/[3] M. Galassi et al., GNU Scientific Library Reference Manual (3rd Ed.), ISBN 0954612078., http://www.gnu.org/software/gsl/

Noreen, Amna; Olaussen, Kåre

2012-10-01

366

Nano-Motion Stage for High-Speed and Precision Positioning on an X-Y Plane  

Microsoft Academic Search

Precision positioning technology with high speed on an X-Y plane which was a coplanar coupling type required a manufacturing inspection for semiconductor and flat display areas, and so on. However, a precise positioning technology with high-speed motion had not been established on the X-Y plane which was coplanar without rotation around a Z axis yet. The authors proposed a new

Shigeki Mori; Yuudai Sato; Akira Sakurada; Akihiro Naganawa; Yotsugi Shibuya; Goro Obinata

2009-01-01

367

[Experimental and theoretical high energy physics program  

SciTech Connect

Experimental and theoretical high-energy physics research at Purdue is summarized in a number of reports. Subjects treated include the following: the CLEO experiment for the study of heavy flavor physics; gas microstrip detectors; particle astrophysics; affine Kac{endash}Moody algebra; nonperturbative mass bounds on scalar and fermion systems due to triviality and vacuum stability constraints; resonance neutrino oscillations; e{sup +}e{sup {minus}} collisions at CERN; {bar p}{endash}p collisions at FNAL; accelerator physics at Fermilab; development work for the SDC detector at SSC; TOPAZ; D-zero physics; physics beyond the standard model; and the Collider Detector at Fermilab. (RWR)

Finley, J.; Gaidos, J.A.; Loeffler, F.J.; McIlwain, R.L.; Miller, D.H.; Palfrey, T.R.; Shibata, E.I.; Shipsey, I.P.

1993-04-01

368

High precision isotopic analyses of uranium and plutonium by total sample volatilization and signal integration  

SciTech Connect

Techniques have been developed which permit rapid, high-precision analyses of uranium and plutonium by multiple-filament thermal ionization mass spectrometry utilizing a commercial multicollector instrument. The salient feature of the method is volatilization of the entire sample while simultaneously integrating the signal from each isotope, thus virtually eliminating the effects of isotope fractionation in the evaporation process. The method permits the analysis of samples much smaller than required for conventional techniques using Faraday collectors and is expected to have application in the analysis of many elements in addition to uranium and plutonium. Run-to-run reproducibilities of <0.02% (RSD) have been obtained for isotope ratios of uranium and plutonium. 7 refs., 5 figs., 4 tabs.

Callis, E.L.; Abernathey, R.M.

1989-01-01

369

The Use of Industrial Robot Arms for High Precision Patient Positioning  

SciTech Connect

The Indiana University Cyclotron Facility (IUCF) is in the process of designing and building the Midwest Proton Radiation Institute (MPRI) [1]. The design process includes the development of several patient treatment systems. This paper discusses the use of two such systems that provide for the high precision positioning of a patient. They are the Patient Positioner System and the X-ray system. The Patient Positioner System positions an immobilized patient on a support device to a treatment position based on a prescribed Treatment Plan. The X-ray system uses an industrial robot arm to position a Digital Radiography Panel to acquire an X-ray image to verify the location of the prescribed treatment volume in a patient by comparing the acquired images with reference images obtained from the patient's Treatment plan.

Katuin, J.E.; Schreuder, A.N.; Starks, W.M.; Doskow, J. [IUCF, 2401 Milo B Sampson Ln, Bloomington, IN 47408 (United States)

2003-08-26

370

High-precision Monte Carlo study of the 3D XY-universality class  

NASA Astrophysics Data System (ADS)

We present a Monte Carlo study of the two-component icons/Journals/Common/phi" ALT="phi" ALIGN="TOP"/>4 model on the simple cubic lattice in three dimensions. By suitable tuning of the coupling constant, icons/Journals/Common/lambda" ALT="lambda" ALIGN="TOP"/>, we eliminate leading-order corrections to scaling. High-statistics simulations using finite-size scaling techniques yield icons/Journals/Common/nu" ALT="nu" ALIGN="TOP"/> = 0.6723(3)[8] and icons/Journals/Common/eta" ALT="eta" ALIGN="TOP"/> = 0.0381(2)[2], where the statistical and systematical errors are given in the first and second bracket, respectively. These results are more precise than any previous theoretical estimate of the critical exponents for the 3D XY universality class.

Hasenbusch, M.; Török, T.

1999-09-01

371

High precision measurements of {sup 26}Na {beta}{sup -} decay  

SciTech Connect

High-precision measurements of the half-life and {beta}-branching ratios for the {beta}{sup -} decay of {sup 26}Na to {sup 26}Mg have been measured in {beta}-counting and {gamma}-decay experiments, respectively. A 4{pi} proportional counter and fast tape transport system were employed for the half-life measurement, whereas the {gamma} rays emitted by the daughter nucleus {sup 26}Mg were detected with the 8{pi} {gamma}-ray spectrometer, both located at TRIUMF's isotope separator and accelerator radioactive beam facility. The half-life of {sup 26}Na was determined to be T{sub 1/2}=1.07128{+-}0.00013{+-}0.00021 s, where the first error is statistical and the second systematic. The logft values derived from these experiments are compared with theoretical values from a full sd-shell model calculation.

Grinyer, G.F.; Svensson, C.E.; Andreoiu, C.; Finlay, P.; Hyland, B.; Phillips, A.A.; Schumaker, M.A.; Valiente-Dobon, J.J. [Department of Physics, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Andreyev, A.N.; Ball, G.C.; Chakrawarthy, R.S.; Hackman, G.; Macdonald, J.A.; Morton, A.C.; Osborne, C.J.; Pearson, C.J.; Sarazin, F.; Scraggs, H.C.; Smith, M.B. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 (Canada); Austin, R.A.E. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4K1 (Canada)] [and others

2005-04-01

372

A new one-detector analysis method for rapid high precision plutonium isotopic measurements  

SciTech Connect

A new method has been developed that achieves plutonium isotopic analysis precisions of better than 2% in counting times of only a few minutes, using only the 59- to 208-keV energy region of a spectrum. This breakthrough was achieved by developing a unique but highly accurate method for delineating the overall ''intrinsic'' efficiency curve, including the plutonium K-shell absorption discontinuity at 121 keV. Consequently, the measured 129- and 148-keV peak intensities can now be used to reliably determine the relative abundances of /sup 239/Pu and /sup 241/Pu. The intense 94- to 104-keV region is also analyzed, providing accurate data for the other isotopes of interest. 5 refs., 3 figs., 2 tabs.

Gunnink, R.

1986-10-28

373

High precision Penning trap mass spectrometry of rare isotopes produced by projectile fragmentation  

NASA Astrophysics Data System (ADS)

The Low Energy Beam and Ion Trap (LEBIT) is the only present facility to combine high precision Penning trap mass spectrometry with fast beam projectile fragmentation. Located at the National Superconducting Cyclotron Laboratory (NSCL), LEBIT is able to measure radionuclides produced in a chemically independent process with minimal decay losses. Recent exotic mass measurements include 66As, 63-66Fe, and 32Si. 66As is a new candidate to test the Conserved Vector Current (CVC) hypothesis. The masses of the neutron-rich iron isotopes provide additional information about the mass surface and the subshell closure at N = 40. 32Si is a member of the A = 32, T = 2 quintet; its measurement permits the most stringent test of the validity of the isobaric multiplet mass equation (IMME). An overview of some recent measurements will be presented as well as advanced techniques for ion manipulation.

Kwiatkowski, A. A.; Barquest, B. R.; Block, M.; Bollen, G.; Campbell, C. M.; Ferrer, R.; Lincoln, D. L.; Morrissey, D. J.; Pang, G. K.; Redshaw, M.; Ringle, R.; Schwarz, S.; Savory, J.

2011-09-01

374

High precision U-Pb zircon ages for Mesozoic igneous rocks from Hong Kong  

NASA Astrophysics Data System (ADS)

Sixteen new high precision U-Pb zircon ages are reported from Jurassic and Early Cretaceous silicic volcanic and plutonic rocks of Hong Kong. When combined with the existing age dataset, the new ages constrain more tightly the timing of major periods of volcanism and plutonism at 162.6 ± 4.5 Ma, 146.7 ± 1.1 Ma, 143.0 ± 1.0 Ma and 140.8 ± 0.6 Ma. However, two ages of 151.9 ± 0.2 Ma and 148.1 ± 0.2 Ma, from eastern New Territories and southern Hong Kong indicate additional and therefore more continuous, albeit pulsed, magmatic activity than previously thought.

Sewell, R. J.; Davis, D. W.; Campbell, S. D. G.

2012-01-01

375

High Precision and High Frequency Four-Quadrant Power Converter [+-600A,+-12V  

Microsoft Academic Search

The LHC (Large Hadron Collider) particle accelerator makes extensive use of true bipolar power converters. All these converters will be installed in excavated caverns underground; hence the necessity for minimum volume and high efficiency for the power converters. This paper presents the design and the realisation of a compact (19\\

Frederick Bordry; P Cussac; A Dupaquier

1999-01-01

376

A high-precision five-degree-of-freedom measurement system based on laser collimator and interferometry techniques  

SciTech Connect

A novel sensitivity improving method for simultaneously measuring five-degree-of-freedom errors of a moving linear stage is proposed based on collimator and interferometry techniques. The measuring principle and parameters of the system are analyzed theoretically. The experimental results proved that the resolution of the linear displacement of the proposed method has twice that of the current linear interferometer, and the resolutions of the two-dimensional straightness error measurement can be improved by a factor of 8 compared with the movement of the retroreflector itself by using multireflection and lens magnification. The resolutions of the pitch and yaw angular error measurement have been improved by a factor of 10 compared with the rotation of the plane mirror itself by using expander lenses. The whole measuring system is characterized of simple structure, small volume, and high precision. The moving component of the measurement system is wireless, which eliminates the errors and inconvenience introduced by the wire connection. Calibration and comparison tests of this system compared with Renishaw laser interferometer system have been carried out. Experimental results show good consistency for measuring a linear guide way.

Kuang Cuifang; Hong En; Ni Jun [School of Information Science and Technology, Beijing Institute of Technology, Beijing 100081 (China); Mechanical Engineering Department, University of Michigan, Ann Arbor, Michigan 48109-2125 (United States)

2007-09-15

377

New precise determination of the high temperature unusual temperature dependent thermopower of liquid divalent cadmium and zinc  

NASA Astrophysics Data System (ADS)

We do not know any precise measurement of the absolute thermopower (ATP) of liquid cadmium and zinc at high temperatures. For liquid cadmium, there are, in the literature, apparent contradictory results. Bath and Kliem and North and Wagner observed that the ATP increases with temperature between 350 °C and 650 °C, but Bradley observed the opposite behaviour between 600 °C and 750 °C. In this work we measured accurately the absolute thermopower of liquid cadmium from the melting point up to 900 °C. We find a maximum around 520 °C, and then the thermopower decreases down to a surprising negative value. To our knowledge, it is the first time that such an unusual behaviour is reported. Nevertheless, it is qualitatively consistent with all the authors mentioned and the apparent contradictory results should only be due to the different temperature ranges of measurements. Using the ATP expression from the Faber-Ziman formalism, we can fit very well the experimental absolute thermopower versus temperature curve with only one adjustable parameter. For this, we have considered that the temperature dependence of the ATP is dominated by the resistivity, and we have introduced the experimental resistivity temperature dependence in the ATP expression. The very good fitting quality demonstrates that our hypothesis is consistent. In contrast, the liquid zinc ATP only increases with temperature. Nevertheless, near 1100 °C, the highest temperature achieved, it shows saturation that may be an indication of a decrease at higher temperature. The same type of fitting gives also quite good results.

Giordanengo, B.; Ben Moussa, A.; Makradi, A.; Chaaba, H.; Gasser, J.-G.

2000-04-01

378

High precision multi-genome scale reannotation of enzyme function by EFICAz  

PubMed Central

Background The functional annotation of most genes in newly sequenced genomes is inferred from similarity to previously characterized sequences, an annotation strategy that often leads to erroneous assignments. We have performed a reannotation of 245 genomes using an updated version of EFICAz, a highly precise method for enzyme function prediction. Results Based on our three-field EC number predictions, we have obtained lower-bound estimates for the average enzyme content in Archaea (29%), Bacteria (30%) and Eukarya (18%). Most annotations added in KEGG from 2005 to 2006 agree with EFICAz predictions made in 2005. The coverage of EFICAz predictions is significantly higher than that of KEGG, especially for eukaryotes. Thousands of our novel predictions correspond to hypothetical proteins. We have identified a subset of 64 hypothetical proteins with low sequence identity to EFICAz training enzymes, whose biochemical functions have been recently characterized and find that in 96% (84%) of the cases we correctly identified their three-field (four-field) EC numbers. For two of the 64 hypothetical proteins: PA1167 from Pseudomonas aeruginosa, an alginate lyase (EC 4.2.2.3) and Rv1700 of Mycobacterium tuberculosis H37Rv, an ADP-ribose diphosphatase (EC 3.6.1.13), we have detected annotation lag of more than two years in databases. Two examples are presented where EFICAz predictions act as hypothesis generators for understanding the functional roles of hypothetical proteins: FLJ11151, a human protein overexpressed in cancer that EFICAz identifies as an endopolyphosphatase (EC 3.6.1.10), and MW0119, a protein of Staphylococcus aureus strain MW2 that we propose as candidate virulence factor based on its EFICAz predicted activity, sphingomyelin phosphodiesterase (EC 3.1.4.12). Conclusion Our results suggest that we have generated enzyme function annotations of high precision and recall. These predictions can be mined and correlated with other information sources to generate biologically significant hypotheses and can be useful for comparative genome analysis and automated metabolic pathway reconstruction.

Arakaki, Adrian K; Tian, Weidong; Skolnick, Jeffrey

2006-01-01

379

Sensitivity studies of high-precision methane column concentration inversion using a line-by-line radiative transfer model  

NASA Astrophysics Data System (ADS)

Hyper-spectral remote sensing may provide an effective solution to retrieve the methane (CH4) concentration in an atmospheric column. As a result of exploring the absorptive characteristics of CH4, an appropriate band is selected from hyperspectral data for the detection of its column concentration with high precision. Following the most recent inversion theory and methods, the line-by-line radiative transfer model (LBLRTM) is employed to forward model the impact of four sensitive factors on inversion precision, including CH4 initial profile, temperature, overlapping gases, and surface albedo. The results indicate that the four optimized factors could improve the inversion precision of atmospheric CH4 column concentration.

Song, Ci; Shu, Jiong; Zhou, Mandi; Gao, Wei

2013-09-01

380

Magnetic Field Noise from High Permeability Magnetic Shields for Precision Measurements  

NASA Astrophysics Data System (ADS)

High permeability magnetic shields often generate magnetic field noise that can limit the sensitivity of precision measurements. We show that calculations based on the fluctuation-dissipation theorem allow evaluation of magnetic field noise, either by current or spin fluctuations, from high permeability metals and ferrites over a broad frequency range. For example, the noise spectrum of a mu-metal shield generally exhibits three distinct frequency dependent behaviors: low frequency 1/f spin noise, white noise due to Johnson noise current, and high frequency roll-off due to self-shielding. To reduce the effect of Johnson noise current, we built a multi-layer shield for a potassium SERF atomic magnetometer using ferrite for the innermost layer. We found that the white noise was reduced from about 20 fT/Hz^1/2, as expected for an all-mu metal shield, to 0.75 fT/Hz^1/2, limited by laser noise. The low frequency 1/f noise agreed well with calculation based on the measured complex permeability of the ferrite. Our method can be used to identify low noise shielding materials for further suppression of shield-generated noise for compact atomic magnetometers.

Lee, S.-K.; Smullin, S. J.; Kornack, T. W.; Romalis, M. V.

2007-06-01

381

QCD Precision Measurements and Structure Function Extraction at a High Statistics, High Energy Neutrino Scattering Experiment: NuSOnG  

SciTech Connect

We extend the physics case for a new high-energy, ultra-high statistics neutrino scattering experiment, NuSOnG (Neutrino Scattering On Glass) to address a variety of issues including precision QCD measurements, extraction of structure functions, and the derived Parton Distribution Functions (PDFs). This experiment uses a Tevatron-based neutrino beam to obtain a sample of Deep Inelastic Scattering (DIS) events which is over two orders of magnitude larger than past samples. We outline an innovative method for fitting the structure functions using a parameterized energy shift which yields reduced systematic uncertainties. High statistics measurements, in combination with improved systematics, will enable NuSOnG to perform discerning tests of fundamental Standard Model parameters as we search for deviations which may hint of 'Beyond the Standard Model' physics.

Adams, T.; /Florida State U.; Batra, P.; /Columbia U.; Bugel, Leonard G.; /Columbia U.; Camilleri, Leslie Loris; /Columbia U.; Conrad, Janet Marie; /MIT; de Gouvea, A.; /Northwestern U.; Fisher, Peter H.; /MIT; Formaggio, Joseph Angelo; /MIT; Jenkins, J.; /Northwestern U.; Karagiorgi, Georgia S.; /MIT; Kobilarcik, T.R.; /Fermilab /Texas U.

2009-06-01

382

High-Precision Half-Life Measurement for the Superallowed {beta}{sup +} Emitter {sup 26}Al{sup m}  

SciTech Connect

A high-precision half-life measurement for the superallowed {beta}{sup +} emitter {sup 26}Al{sup m} was performed at the TRIUMF-ISAC radioactive ion beam facility yielding T{sub 1/2}=6346.54{+-}0.46{sub stat{+-}}0.60{sub syst} ms, consistent with, but 2.5 times more precise than, the previous world average. The {sup 26}Al{sup m} half-life and ft value, 3037.53(61) s, are now the most precisely determined for any superallowed {beta} decay. Combined with recent theoretical corrections for isospin-symmetry-breaking and radiative effects, the corrected Ft value for {sup 26}Al{sup m}, 3073.0(12) s, sets a new benchmark for the high-precision superallowed Fermi {beta}-decay studies used to test the conserved vector current hypothesis and determine the V{sub ud} element of the Cabibbo-Kobayashi-Maskawa quark mixing matrix.

Finlay, P.; Svensson, C. E.; Green, K. L.; Leach, K. G.; Phillips, A. A.; Sumithrarachchi, C. S. [Department of Physics, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Ettenauer, S. [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 (Canada); Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, V6T 1Z4 (Canada); Ball, G. C.; Bandyopadhyay, D.; Djongolov, M.; Hackman, G.; Pearson, C. J.; Williams, S. J [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 (Canada); Leslie, J. R. [Department of Physics, Queen's University, Kingston, Ontario, K7L 3N6 (Canada); Andreoiu, C.; Cross, D. S. [Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, V5A 1S6 (Canada); Austin, R. A. E. [Astronomy and Physics Department, Saint Mary's University, Halifax, Nova Scotia, B3H 3C3 (Canada); Demand, G. [Department of Physics, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); Department of Physics, Queen's University, Kingston, Ontario, K7L 3N6 (Canada); Garrett, P. E.; Triambak, S. [Department of Physics, University of Guelph, Guelph, Ontario, N1G 2W1 (Canada); TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, V6T 2A3 (Canada)

2011-01-21

383

Precision measurement of the ab-plane London penetration depth in high temperature superconducting thin films  

NASA Astrophysics Data System (ADS)

The temperature change of the in-plane penetration depth ?? ab ( T)=? ab ( T)-? ab (0) of HTS thin films was determined with an experimental resolution of better than 0.2Å using a novel dc-technique based on the measurement of the magnetic field dependence of the critical current of bicrystal grain boundary Josephson junctions (GBJs). Over a wide temperature range the data obtained for different high temperature superconductors confirm with high accuracy the theoretical prediction for a d x 2 -y 2-symmetry of the superconducting order parameter in the limit of weak coupling.

Froehlich, O. M.; Beck, A.; Richter, P.; Gross, R.

1996-02-01

384

Finding the "true" age: ways to read high-precision U-Pb zircon dates  

NASA Astrophysics Data System (ADS)

Refined U-Pb dating techniques, applying an empirical chemical abrasion treatment prior to analysis [1], and using a precisely calibrated double isotope Pb, U EARTHTIME tracer solution, have led to an unprecedented <0.1% precision and accuracy of obtained 206Pb/238U dates of single zircon crystals or fragments. Results very often range over 10e4 to 10e6 years and cannot be treated as statistically singular age populations. The interpretation of precise zircon U-Pb ages is biased by two problems: (A) Post-crystallization Pb loss from decay damaged areas is considered to be mitigated by applying chemical abrasion techniques. The success of such treatment can, however, not be assumed a priori. The following examples demonstrate that youngest zircons are not biased by lead loss but represent close-to-youngest zircon growth: (i) coincidence of youngest zircon dates with co-magmatic titanite in tonalite; (ii) coincidence with statistically equivalent clusters of 206Pb/238U dates from zircon in residual melts of cogenetic mafic magmas; (iii) youngest zircons in ash beds of sedimentary sequences do not violate the stratigraphic superposition, whereas conventional statistical interpretation (mean or median values) does; (iv) results of published inter-laboratory cross-calibration tests using chemical abrasion on natural zircon crystals of the same sample arrive at the same 206Pb/238U result within <0.1% (e.g., [2]); (v) Youngest crystals coincide in age with the astronomical age of hosting cyclic sediments. Residual lead loss may, however, still be identified in the case of single, significantly younger dates (>3 sigma), and are common in many pre-Triassic and hydrothermally altered rocks. (B) Pre-eruptive/pre-intrusive growth is found to be the main reason for scattered zircon ages in igneous rocks. Zircons crystallizing from the final magma batch are called autocrystic [3]. Autocrystic growth will happen in a moving or stagnant magma shortly before or after the rheological lockup by the crystals. Last crystallizing zircons in the interstitial melt may therefore postdate emplacement of the magma. The range of 206Pb/238U ages may yield a time frame for the cooling of a given magma batch, which could be added to quantitative thermal models of magma emplacement and cooling. Hf isotopes and trace elements of the dated zircon are used to trace the nature of the dated grains [4], specifically for identification of crystals that form earlier at lower crustal levels (antecrysts). Autocrystic zircons typically show, e.g., distinctly different (higher or lower) Th/U ratios. Cautiously interpreted high-precision U-Pb data of chemically abraded zircons may resolve the evolution of a magmatic system from its roots to final emplacement or eruption, trace fractional crystallization of zircon and other accessory and major phases in a magma batch, and add quantitative temporal constraints to thermal models. The proposed interpretation scheme thus adds significant information compared to conventional statistics. [1] Mattinson J., 2005, Chem. Geol. 200, 47-66; ; [2] Slama et al., 2008, Chem. Geol. 249, 1-35; [3] Miller et al., 2007, J. Volc. Geotherm. Res. 167, 282-299; [4] Schoene et al., 2010, Geochim. Cosmochim. Acta 74, 7144-7159

Schaltegger, U.; Schoene, B.; Ovtcharova, M.; Sell, B. K.; Broderick, C. A.; Wotzlaw, J.

2011-12-01

385

Advanced navigation and guidance for high-precision planetary landing on Mars  

NASA Astrophysics Data System (ADS)

Several international missions scheduled for years 2011--2013 have as objective a Mars surface sample return to Earth. In order to gather samples of high scientific quality, these missions require precise landing at preselected locations on Mars. Since the previous missions on Mars have flown unguided and highly inaccurate atmospheric entry, a new generation of landing systems must be developed. It was demonstrated by Wolf et al., [2004] that the most efficient way to increase the landing accuracy is achieved during the atmospheric entry by steering the vehicle trajectory in order to eliminate the dispersions caused at entry and accumulated during the hypersonic phase. Thus, the research project proposed here will investigate the problem and bring advances on atmospheric entry navigation, guidance and control techniques applied to atmospheric entry on Mars. The state-of-the-art revealed several limitations on the current techniques such as the lack of proper navigation system and the inability to guide the trajectory efficiently in presence of disturbances and entry conditions uncertainties. On the theoretical side, the nonlinear state estimators required for navigation use algorithms that are a heavy computational burden for the onboard processor. Following these limitations, the research presented in this document is conducted along three paths: estimation theory, entry navigation techniques and entry guidance techniques in order to investigate on advances to achieve high precision landing. After an in-depth investigation of the theoretical background required to understand the atmospheric entry dynamics, a number of issues are addressed and the following substantial contributions regarding Mars atmospheric entry navigation and guidance are achieved. (C1) A theoretical improvement of the unscented Kalman Filter by merging two variants in the literature. The resulting technique has the advantages of both former algorithms. (C2) Four navigation concepts using inertial measurement units and radio ranging from reference beacons (known and unknown) for complete state estimation, atmospheric density estimation and vehicle aerodynamics estimation. (C3) The successful application of the unscented Kalman filtering to atmospheric entry for both state and parameter estimation. (C4) The development of two analytical predictor-corrector guidance techniques for atmospheric entry. The first uses two constant flightpath angle segments in order to meet the terminal altitude, velocity and downrange requirements. The second is based on a single density-proportional flightpath angle segment. These contributions have been reported in three conference papers and one scientific journal.

Levesque, Jean-Francois

386

Compliant high-precision E-quintet ratcheting (CHEQR) mechanism for safety and arming devices  

Microsoft Academic Search

Ratchet and pawl mechanisms are used in safety applications to provide mechanical isolation between inputs and an output to insure that extreme environmental conditions do not inadvertently allow an unexpected output. These devices have become smaller and are approaching a size regime where traditional precision components, such as precision bearings and springs, are not available. This paper introduces the compliant

John A. Kennedy; Larry L. Howell; William Greenwood

2007-01-01

387

Experimental high-velocity missile head injury.  

PubMed

A standardized experimental high-velocity penetrating head-injury model has been produced in which pathological lesions were observed, not only in the wound track but at sites more remote from the track in the hypothalamus, brain stem and cerebellum. Diffuse subarachnoid haemorrhage was common and intraventricular haemorrhage was a constant feature. Other constant histological abnormalities were:L 1. Perivascular "ring' haemorrhages. 2. Perivascular haemorrhage with a surrounding zone of decreased staining intensity. 3. Perivascular increased staining intensity. 4. Areas of decreased staining intensity apparently dissociated from areas of haemorrhage. The pathogenesis of the perivascular lesions is discussed and preliminary studies suggest that these may be the site of early oedema. The implications of this experiment for military surgery and for ballistic protection of the head are discussed. PMID:6183206

Allen, I V; Scott, R; Tanner, J A

1982-09-01

388

High-precision Timing of Five Millisecond Pulsars: Space Velocities, Binary Evolution, and Equivalence Principles  

NASA Astrophysics Data System (ADS)

We present high-precision timing of five millisecond pulsars (MSPs) carried out for more than seven years; four pulsars are in binary systems and one is isolated. We are able to measure the pulsars' proper motions and derive an estimate for their space velocities. The measured two-dimensional velocities are in the range 70-210 km s-1, consistent with those measured for other MSPs. We also use all the available proper motion information for isolated and binary MSPs to update the known velocity distribution for these populations. As found by earlier works, we find that the velocity distribution of binary and isolated MSPs are indistinguishable with the current data. Four of the pulsars in our observing program are highly recycled with low-mass white dwarf companions and we are able to derive accurate binary parameters for these systems. For three of these binary systems, we are able to place initial constraints on the pulsar masses with best-fit values in the range 1.0-1.6 M ?. The implications of the results presented here to our understanding of binary pulsar evolution are discussed. The updated parameters for the binary systems studied here, together with recently discovered similar systems, allowed us to update previous limits on the violation of the strong equivalence principle through the parameter |?| to 4.6 × 10-3 (95% confidence) and the violation of Lorentz invariance/momentum conservation through the parameter |\\hat{\\alpha }_3| to 5.5 × 10-20 (95% confidence).

Gonzalez, M. E.; Stairs, I. H.; Ferdman, R. D.; Freire, P. C. C.; Nice, D. J.; Demorest, P. B.; Ransom, S. M.; Kramer, M.; Camilo, F.; Hobbs, G.; Manchester, R. N.; Lyne, A. G.

2011-12-01

389

High precision Compton backscatter maps of myocardial wall dynamics. Theory and applications  

SciTech Connect

Compton backscatter imaging (CBI) is a technique that uses x-rays scattered from the closed-chest surface of the heart to obtain high frequency (5 msec) and high precision (+/- 0.1 mm SD) measurements of regional surface displacements and velocities. These measurements are acquired in a three-dimensional format that allows the reconstruction of the epicardial surface and the creation of color coded displacement and velocity maps at many time points during the cardiac cycle. Applications of the technique are shown to characterize detailed regional normal wall displacement and velocity patterns, and the significant alteration of those patterns after coronary embolization. The technique is also applied to the characterization of early diastolic wall dynamics. CBI measurements show that a brief and somewhat paradoxical inward displacement of the anterior ventricular wall occurs during early diastole in normal canines. The wall dynamics associated with this inward displacement suggest a brief collapse of the ventricle subsequent to aortic valve closure. Diastolic collapse velocities and displacements are significantly altered subsequent to coronary occlusion with mean and maximum collapse velocities decreasing by 50% and concomitant inward displacements decreasing by 40%. Data acquisition with CBI is non-invasive, does not require contrast agents or radioisotopes, and uses low irradiation levels (125 kVp, 3-5 ma). The average radiation dose to the heart for a typical study is 250 mrem, significantly lower than that of other radiation based imaging techniques.

McInerney, J.J.; Copenhaver, G.L.; Herr, M.D.; Morris, D.L.; Zelis, R. (Pennsylvania State Univ., Hershey (USA))

1989-09-01

390

An approach to segment lung pleura from CT data with high precision  

NASA Astrophysics Data System (ADS)

A new approach to segment pleurae from CT data with high precision is introduced. This approach is developed in the segmentation's framework of an image analysis system to automatically detect pleural thickenings. The new technique to carry out the 3D segmentation of lung pleura is based on supervised range-constrained thresholding and a Gibbs-Markov random field model. An initial segmentation is done using the 3D histogram by supervised range-constrained thresholding. 3D connected component labelling is then applied to find the thorax. In order to detect and remove trachea and bronchi therein, the 3D histogram of connected pulmonary organs is modelled as a finite mixture of Gaussian distributions. Parameters are estimated using the Expectation-Maximization algorithm, which leads to the classification of that pulmonary region. As consequence left and right lungs are separated. Finally we apply a Gibbs-Markov random field model to our initial segmentation in order to achieve a high accuracy segmentation of lung pleura. The Gibbs- Markov random field is combined with maximum a posteriori estimation to estimate optimal pleural contours. With these procedures, a new segmentation strategy is developed in order to improve the reliability and accuracy of the detection of pleural contours and to achieve a better assessment performance of pleural thickenings.

Angelats, E.; Chaisaowong, K.; Knepper, A.; Kraus, T.; Aach, T.

2008-04-01

391

High-Precision Isotope Analysis Of Uranium And Thorium By Tims  

SciTech Connect

The U.S. Geological Survey (USGS) Yucca Mountain Project Branch laboratory in Denver, Colorado, conducts routine high-precision isotope analyses of uranium (U) and thorium (Th) using thermal ionization mass-spectrometry (TIMS). The measurements are conducted by a solid-source mass-spectrometer equipped with a Faraday multi-collector system and an energy filter in front of an active-film-type secondary electron multiplier (SEM). The abundance sensitivity of the instrument (signal at mass 237 over {sup 238}U in natural U) with the energy filter is {approx} 15 x 10{sup -9} and peak tails are reduced by a factor of {approx}100 relative to the Faraday cup measurements. Since instrument installation in April 2004, more than 500 rock and water samples have been analyzed in support of isotope-geochemical studies for the U.S. Department of Energy's Yucca Mountain Project. Isotope ratios of sub-nanogram to microgram U and Th samples are measured on graphite-coated single-filament and double-filament assemblies using zone-refined rhenium filaments. Ion beams less than 5 millivolt (mV) are measured with the SEM, which is corrected for non-linearity on the basis of measurements of National Institute of Standards and Technology (NIST) U-500 and 4321 B standards with ion beams ranging from 0.01 to 8 mV. Inter-calibration between the SEM and the Faraday multi-collector is performed for every mass cycle using a {approx}5 mV beam switched between Faraday cup and SEM ('bridging' technique), because SEM-Faraday inter-calibrations prior to the measurement failed to produce acceptable results. Either natural ({sup 235}U) or artificial ({sup 236}U, {sup 229}Th) isotopes were used for the bridging. Separate runs are conducted for minor isotopes using SEM only. These techniques result in high within-run precisions of <0.1 to 0.2 percent for {sup 234}U/{sup 238}U and 0.2 to 0.5 percent for {sup 230}Th/{sup 238}U.

L.A. Neymark

2006-08-31

392

High-precision branching-ratio measurement for the superallowed ?+ emitter 74Rb  

NASA Astrophysics Data System (ADS)

A high-precision branching-ratio measurement for the superallowed ?+ decay of 74Rb was performed at the TRIUMF Isotope Separator and Accelerator (ISAC) radioactive ion-beam facility. The scintillating electron-positron tagging array (SCEPTAR), composed of 10 thin plastic scintillators, was used to detect the emitted ? particles; the 8? spectrometer, an array of 20 Compton-suppressed HPGe detectors, was used for detecting ? rays that were emitted following Gamow-Teller and nonanalog Fermi ?+ decays of 74Rb; and the Pentagonal Array of Conversion Electron Spectrometers (PACES), an array of 5 Si(Li) detectors, was employed for measuring ?-delayed conversion electrons. Twenty-three excited states were identified in 74Kr following 8.241(4)×108 detected 74Rb ? decays. A total of 58 ?-ray and electron transitions were placed in the decay scheme, allowing the superallowed branching ratio to be determined as B0=99.545(31)%. Combined with previous half-life and Q-value measurements, the superallowed branching ratio measured in this work leads to a superallowed ft value of 3082.8(65) s. Comparisons between this superallowed ft value and the world-average-corrected Ft¯ value, as well as the nonanalog Fermi branching ratios determined in this work, provide guidance for theoretical models of the isospin-symmetry-breaking corrections in this mass region.

Dunlop, R.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Towner, I. S.; Andreoiu, C.; Chagnon-Lessard, S.; Chester, A.; Cross, D. S.; Finlay, P.; Garnsworthy, A. B.; Garrett, P. E.; Glister, J.; Hackman, G.; Hadinia, B.; Leach, K. G.; Rand, E. T.; Starosta, K.; Tardiff, E. R.; Triambak, S.; Williams, S. J.; Wong, J.; Yates, S. W.; Zganjar, E. F.

2013-10-01

393

High precision predictions for near-Earth asteroids: the strange case of (3908) Nyx  

NASA Astrophysics Data System (ADS)

In November 2004 near-Earth asteroid (3908) Nyx was successfully observed from the Arecibo radio telescope. However, the radar measurements turned out to be 7.5 sigma away from the orbital prediction. We prove that this anomaly was caused by a poor astrometric treatment and an inaccurate dynamical model. To improve the astrometric treatment, we applied the Chesley et al. (2010) debiasing and weighting scheme, and used an aggressive outlier rejection scheme. The main issue related to the dynamical model is due to the unaccounted Yarkovsky effect. Though the dataset available in 2004 allowed at best a marginal detection of the Yarkovsky signal, including the Yarkovsky effect in the model closes the gap between the orbital prediction and the radar measurements by both improving the nominal prediction and increasing the prediction uncertainty to a more realistic level. This analysis is an important lesson that shows the sensitivity of high precision predictions to the astrometric treatment and the Yarkovsky effect. By using the full observational dataset we obtain a 5 sigma detection of the Yarkovsky effect acting on Nyx from which we derive constraints on thermal inertia and bulk density. In particular, we obtain that the bulk density of Nyx is close to 1 g/cm^3. To make sure that our results are not corrupted by an asteroid impact or a close approach with a perturbing asteroid not included in our dynamical model, we rule out the possibility that Nyx experienced an instantaneous velocity variation while crossing the Main Belt region.

Farnocchia, Davide; Chesley, S. R.; Tholen, D. J.; Micheli, M.

2013-10-01

394

Parallel high-precision orbit propagation using the modified Picard-Chebyshev method  

NASA Astrophysics Data System (ADS)

The modified Picard-Chebyshev method, when run in parallel, is thought to be more accurate and faster than the most efficient sequential numerical integration techniques when applied to orbit propagation problems. Previous experiments have shown that the modified Picard-Chebyshev method can have up to a one order magnitude speedup over the 12th order Runge-Kutta-Nystrom method. For this study, the evaluation of the accuracy and computational time of the modified Picard-Chebyshev method, using the Java Astrodynamics Toolkit high-precision force model, is conducted to assess its runtime performance. Simulation results of the modified Picard-Chebyshev method, implemented in MATLAB and the MATLAB Parallel Computing Toolbox, are compared against the most efficient first and second order Ordinary Differential Equation (ODE) solvers. A total of six processors were used to assess the runtime performance of the modified Picard-Chebyshev method. It was found that for all orbit propagation test cases, where the gravity model was simulated to be of higher degree and order (above 225 to increase computational overhead), the modified Picard-Chebyshev method was faster, by as much as a factor of two, than the other ODE solvers which were tested.

Koblick, Darin C.

395

High-precision gasket thickness measuring and classifying system based on line-structured light  

NASA Astrophysics Data System (ADS)

In this paper, a high-precision flat gasket thickness measuring and classifying system based on line-structured light is presented. The system consists of a part feeding device, a measurement platform, a measurement and control subsystem and a classifying subsystem. The measurement system is based on the optical trigonometry measurement principle. Different from other common measurement system, a line-structured light instead of a beam is projected to the surface of the measured object. From a stripe the measured result will get more confirmation than a single beam spot. More than one frame of image are grabbed and averaged to reduce the random error. The gravity center algorithm is used to extract the center-point of the stripe in one column. According to the least squares method, a straight line can be fitted from gravity center-points extracted. A virtual grate is designed to improve the resolution of the measurement system. The calibration of the measurement system is designed and realized. An experiment is built and the measurement result is analyzed. The result shows that the uncertainty of the measurement system is limited in +/- 0.003mm. And this system can be used for classifying the gaskets by thickness.

Wu, Qinghua; He, Tao; Shi, Tielin

2013-01-01

396

High-precision Measurements of Planetary Spin States: Mercury, Venus, Europa, Ganymede  

NASA Astrophysics Data System (ADS)

Rotation studies have enabled profound developments in our understanding of the Earth and Moon. Likewise, measurements of the rotation of other bodies can provide powerful probes of planetary interior structure and processes. This talk will describe ongoing high-precision measurements of the rotation of Mercury, Venus, and the Galilean Satellites. The data are obtained by recording radar speckles at two separate telescopes, the 70 m Goldstone antenna and the 100 m Green Bank Telescope. At Mercury, measurements have been used to infer the polar moment of inertia (C/MR^2 = 0.346 +/- 0.014) and the radius of the core 2000 km, or ~82% of the planetary radius) [Margot et al, J. Geophys. Res., 117, 2012]. The Venus observations reveal that the spin period is not constant. The variations are compatible with percent-level changes in atmospheric angular momentum transferred to the solid planet. Europa and Ganymede observations will be used to place bounds on obliquity and libration. The former may explain remarkable surface features, and the latter is strongly dependent on the thickness and rheology of the icy shell, perhaps the most important determinants of the moons' astrobiological potential.

Margot, Jean-Luc; Campbell, D. B.; Peale, S. J.; Ghigo, F. D.

2013-01-01

397

A high-precision earth sensor with three separated FOVs for aircraft application  

NASA Astrophysics Data System (ADS)

The earth sensors are currently used in spacecrafts. Most of them with a single field of view (FOV) for earth observation are not applied to aircrafts in the atmosphere. For the use of the aircraft at 70 ~ 100km in the atmosphere, this paper proposes a separate triple-FOV earth sensor based on infrared detectors. By sensing the earth-horizon, the triple-FOV earth sensor obtains the geocentric vector, and calculates the altitude of the aircraft at the same time. The earth sensor uses three pieces of infrared detectors at 14 ~ 16?m. To sense the infrared light could ensure that the earth sensor does the same operation at night and day regardless of the weather and the light impact of the sun and the moon. The optical axes of the three fields of view are positioned at 120° from each other in the horizontal plane, and the angle between the optical axes and the vertical direction is 82.86°. Considering the model of the surface of the earth's atmosphere, the earth's radius and so on, the mathematical model of the triple-FOV earth sensor is established. From 70km to 100km, the result of simulation shows that the altitude measurement accuracy is better than 100m and the angle measurement error is 3.8". The earth sensor can provide high-precision position information, and make data fusion with additional sensors to achieve autonomous navigation of aircrafts.

Wang, Hongjian; Xing, Fei; Fan, Peirong; Wang, Chong; You, Zheng

2013-08-01

398

High-precision measurement of satellite range and velocity using the EISCAT radar  

NASA Astrophysics Data System (ADS)

This paper is a continuation of an earlier work by Nygrén et al. (2012), where the velocity of a hard target was determined from a set of echo pulses reflected by the target flying through the radar beam. Here the method is extended to include the determination of range at a high accuracy. The method is as follows. First, the flight time of the pulse from the transmitter to the target is determined at an accuracy essentially better than the accuracy given by the sampling interval. This method makes use of the fact that the receiver filtering creates slopes at the phase flips of the phase modulated echo pulse. A precise flight time is found by investigating the echo amplitude within this slope. A value of velocity is calculated from each echo pulse as explained in the earlier paper. Next, the ranges together with velocities from a single beam pass are combined to a measurement vector for a linear inversion problem. The solution of the inversion problem gives the time-dependent range and velocity from the time interval of satellite flight through the radar beam. The method is demonstrated using the EISCAT (European Incoherent Scatter) UHF radar and radio pulses reflected by a satellite. The achieved standard deviations of range are about 5-50 cm and those of velocity are about 3-25 mm s-1.

Markkanen, J.; Nygrén, T.; Markkanen, M.; Voiculescu, M.; Aikio, A.

2013-05-01

399

Towards High-Precision Ground-Based Astrometry: Differential Delay Lines for PRIMA@VLTI  

NASA Astrophysics Data System (ADS)

Deriving unambiguously the orbital parameters and masses of extrasolar planets requires at least 2-dimensional information on either the positions or motions of the planet directly (currently out of reach) or, indirectly, of the host star. The latter can be done with high-precision astrometry at the 10 microarcsec level. To achieve this goal, a consortium with partners from Germany, the Netherlands, and Switzerland, in agreement with ESO, will enhance the PRIMA system at the VLTI with Differential Delay Lines. The PRIMA facility will implement dual-star interferometry at the VLTI, thus enabling narrow-angle differential astrometry. The purpose of the Differential Delay Lines in PRIMA is to increase the astrometric accuracy by separating the large OPD correction terms which are common for target and reference star from the small differential terms, and to increase the sensitivity by stabilizing the fringe pattern and thus allow for longer integrations. This paper gives an overview of the PRIMA-DDL project, which consists of developing hardware, astrometric operation tools, and data reduction software, and outlines the anticipated astrometric planet search program to be carried out with this facility.

Launhardt, R.; Henning, Th.; Queloz, D.; Quirrenbach, A.; Bakker, E. J.; Baumeister, H.; Bizenberger, P.; Bleuler, H.; Dändliker, R.; Delplancke, F.; Derie, F.; Fleury, M.; Glindemann, A.; Gillet, D.; Hanenburg, H.; Jaffe, W.; de Jong, J. A.; Köhler, R.; Maire, C.; Mathar, R. J.; Michellod, Y.; Müllhaupt, P.; Murakawa, K.; Pepe, F.; Le Poole, R. S.; Pragt, J.; Reffert, S.; Sache, L.; Scherler, O.; Ségransan, D.; Setiawan, J.; Sosnowska, D.; Tubbs, R. N.; Venema, L.; Wagner, K.; Weber, L.; Wüthrich, R.

2005-10-01

400

High-precision calculation of the equation of state and crystallographic phase stability for aluminum  

SciTech Connect

High-precision, all-electron, full-potential, local-density approximation (LDA) calculations are used to determine the static lattice equation of state (EOS) and crystalline phase stability of Al to 1 TPa. The low-pressure properties found here are consistent with the results of other nonrelativistic LDA calculations, but differ significantly from the results of relativistic LDA or gradient-dependent approximation calculations. The theoretical 300-K isotherm for fcc Al, obtained by adding phonon effects to the static lattice EOS, is in reasonable agreement with room temperature data up to 220 GPa. The predicted static-lattice phase sequence for Al is fcc{r_arrow}hcp{r_arrow}bcc with the transitions occurring at 205{plus_minus}20 GPa and 565{plus_minus}60 GPa. Estimation of the possible impact of phonons on the fcc{r_arrow}hcp transition produces a fairly firm upper bound of 290 GPa (282) on the room-temperature (zero temperature) fcc{r_arrow}hcp transition pressure. This result suggests that a recent diamond-anvil-cell experiment came very close to achieving the fcc{r_arrow}hcp transition. {copyright} {ital 1996 The American Physical Society.}

Boettger, J.C. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Trickey, S.B. [Quantum Theory Project, Departments of Physics and of Chemistry, University of Florida, Gainesville, Florida 32611 (United States)

1996-02-01

401

High-precision, longitudinal, disc-averaged magnetic field measurements of ? Canis Minoris and ? Leporis.  

NASA Astrophysics Data System (ADS)

High-precision longitudinal, disc-averaged magnetic field measurements have been made on two late-type stars, ? CMi (HR 2943) and ? Lep (HR 1829). A magneto-optical filter has been used to measure the degree of circular polarization in the wings of a line of neutral potassium (7699 A) formed in the atmosphere of the target star. From 10 nights of data taken on ? CMi on the 1.9-m reflector at the South African Astronomical Observatory (SAAO) in 1993 January, an upper limit to any net longitudinal field component present - assuming the field to be constant over the period of observation - of -0.40+/-0.26G was established. Similarly, upper limits for ? Lep of -4.3+/-6.4G and -0.7+/-1.6G were established, from 4 and 10 nights of data taken in 1992 and 1993 January respectively. No significant, periodic, day-to-day variations were seen in the three time series of data.

Bedford, D. K.; Chaplin, W. J.; Davies, A. R.; Innis, J. L.; Isaak, G. R.; Speake, C. C.

1995-01-01

402

Reliable high-repetition-rate femtosecond microJoule fiber lasers for precision applications  

NASA Astrophysics Data System (ADS)

As applications demanding microJoule level pulses at "real-time" rates of delivery increase, and the expectations in terms of long-term, reliable, high quality performance become greater, fiber lasers are becoming increasingly attractive sources. When a combination of excellent beam quality, flexibility in design for repetition rate over 100 kHz - 5 MHz, and robust design for operation in a variety of environments, in a plug-and-play, non-water cooled package are necessary, IMRA"s fiber chirped-pulse amplifier (FCPA) system delivers in a compact, single-box solution. This type of laser has particular promise in precision material processing applications, enabling the use of technology that was previously considered too unstable or difficult to use. The basis for this advanced technology is a novel Yb:fiber oscillator/amplifier combination. The modular design architecture ensures a very robust construction that is well-suited to integration into commercial systems. To show the utility of such a laser in commercial applications, results of ablation thresholds and processing tests of various materials including metals and dielectrics are presented using IMRA"s FCPA &muJewel femtosecond fiber laser.

Stock, Michelle L.; Sucha, Gregg D.; Bovatsek, James; Yamamoto, Tadashi; Arai, Alan

2005-03-01

403

Optimized precision micromachining using commercially available high-repetition rate microjoule femtosecond fiber lasers  

NASA Astrophysics Data System (ADS)

Fiber lasers offer an excellent technology base for production of an industrial-quality tool for precision microfabrication, answering the need to expand the capabilities of laser material processing beyond traditional welding, cutting, and other industrial processes. IMRA's FCPA ?JewelTM femtosecond fiber laser has been developed to address the particular need for direct-write lasers for creation of clean and high-quality micron and sub-micron features in materials of commercial interest. This flexible Yb:fiber chirped-pulse amplification architecture, capable of operating at rep-rates between 100 kHz and 5 MHz, balances the need for higher-repetition rate with that of sufficient pulse energy to work at or near ablation threshold, while meeting industrial standards for temperature, shock and vibration. Demonstration of the need for higher-repetition rates for direct write processes will be provided in this paper. Further, results of laser-processing of materials typically used in flat panel displays, photomasks, and waveguide production using the FCPA ?JewelTM laser will be presented.

Stock, Michelle L.; Shah, Lawrence; Liu, Bing; Yoshida, Makoto; Yoshino, Fumiyo; Bovatsek, James; Arai, Alan

2006-03-01

404

Widely tunable difference frequency generation source for high-precision mid-infrared spectroscopy.  

PubMed

We have developed a widely tunable mid-infrared difference frequency generation (DFG) source by mixing ~ 1 W Ti:sapphire laser and 6 W Nd:YAG laser beams in a 50-mm MgO-doped long periodically poled lithium niobate (MgO:PPLN). The power of the DFG source is > 2 mW over the tuning range of 2.66-4.77 ?m and its free-running linewidth is about 100 kHz. Combining various frequency stabilisation schemes for the Nd:YAG laser and the Ti:sapphire laser, the DFG frequency can be precisely controlled. Besides, its frequency can be determined better than 12 kHz by measuring the Ti:sapphire laser frequency using an optical frequency comb. Two high resolution spectroscopic studies on (12)C(16)O(2) molecule are demonstrated using this DFG source. The saturation spectra of R(18) and R(60) transitions of 00(0)1 ? 00(0)0 fundamental band at 4.2 ?m and P(20) transition of [10(0)1, 02(0)1](I) ? 00(0)0 band at 2.7 ?m have been observed and their absolute transition frequencies are measured with an accuracy better than 30 kHz. PMID:23609634

Liao, Chun-Chieh; Lien, Yu-Hung; Wu, Kuo-Yu; Lin, Yan-Rung; Shy, Jow-Tsong

2013-04-22

405

A high-precision angle encoder for a 10-m submillimeter antenna  

NASA Astrophysics Data System (ADS)

We report measurements of angle error characteristics of new high-precision multi-speed resolvers developed for a 10-m submillimeter telescope of Nobeyama Radio Observatory. We have found the resolvers have an accuracy of 0.03" rms and 0.26" peak-to-peak, which is well below the error budget assigned to the angle encoder in the LMSA/ALMA project (0.15 - 0.2"). The error pattern in the raw readout had simple characteristics and was only composed of a few Fourier components which are associated with the number of winding poles and core slot number of stator. The 4" peak-to-peak error in the raw readout is reduced to less than 1/15 by the PROM correction. We have also found that shaft misalignment causes only small changes of error pattern (0.08" error per 0.10 mm shaft misalignment), which enables us to install the resolver simply by the fitting. The temperature dependence of error pattern also seems to be small enough for the operation temperature range specified in the project.

Ukita, Nobuharu; Ezawa, Hajime; Mimura, Hisashi; Suganuma, Akira; Kitazawa, Kanji; Masuda, Tadashi; Kawaguchi, Noboru; Sugiyama, Ryuichi; Miyawaki, Keizou

2001-03-01

406

Sedimentations on high-precision surfaces of advanced materials by magnetorheological finishing  

NASA Astrophysics Data System (ADS)

Magnetorheological finishing (MRF) is a computer controlled polishing (CCP) technique for high precision surfaces. The process uses a magnetorheological fluid which stiffens in a magnetic field and thus acts as the polishing tool. A standard MR fluid consists of magnetic carbonyl iron (CI) particles, nonmagnetic polishing abrasives and liquid. To delaying oxidation of the iron particles and avoiding agglomeration the liquid consists of water completed with stabilizers. For the material removal and smoothing of the surface mostly cerium oxide or diamond is used. The materials to be polished may tend toward to different sedimentations of the MR fluid on the machined surface. These sedimentations result from the machining and may develop a polishing layer with MR fluid components. At the University of Applied Sciences Deggendorf analysis of the machined surface are made by the scanning electronic microscope (SEM) to determine the sedimentations of the finishing. The results of the research display the influence for the surface properties due to developing polishing layer by magnetorheological finishing.

Geiss, Andreas; Schinhaerl, Markus; Pitschke, Elmar; Rascher, Rolf; Sperber, Peter; Slabeycius, Juraj

2006-08-01

407

A high-precision method to measure thermal conductivity of solids using reversible heat flux  

NASA Astrophysics Data System (ADS)

In the thermal conductivity measurement of solids using the traditional steady-state methods, it is observed that the test results differ from their standard values when only one directional heat flux is introduced. Analysis of the results shows that the additive errors are considerable and cannot be ignored. To minimize the additive errors, a high-precision method by alternating the direction of heat flux in steady-state thermal conductivity measurement of solids is proposed. In this method, the additive errors are diminished by using the data corresponding to both forward and reverse heat flux. Meanwhile, a modified thermal instrument is designed and established to measure the thermal conductivity of solids. Simultaneous calibration of the thermal instrument has been processed to improve the measurement accuracy of temperature readings. The thermal conductivities of samples 99.999% standard pure copper and Elkonite copper–tungsten alloy 30W3 are measured and compared with their reference values to verify the accuracy of the method. The results indicate that the processing data well match the reference values.

Zhang, Ping; Shi, Bo; Xuan, YiMin; Li, Qiang

2013-09-01

408

Quantitative design of regulatory elements based on high-precision strength prediction using artificial neural network.  

PubMed

Accurate and controllable regulatory elements such as promoters and ribosome binding sites (RBSs) are indispensable tools to quantitatively regulate gene expression for rational pathway engineering. Therefore, de novo designing regulatory elements is brought back to the forefront of synthetic biology research. Here we developed a quantitative design method for regulatory elements based on strength prediction using artificial neural network (ANN). One hundred mutated Trc promoter & RBS sequences, which were finely characterized with a strength distribution from 0 to 3.559 (relative to the strength of the original sequence which was defined as 1), were used for model training and test. A precise strength prediction model, NET90_19_576, was finally constructed with high regression correlation coefficients of 0.98 for both model training and test. Sixteen artificial elements were in silico designed using this model. All of them were proved to have good consistency between the measured strength and our desired strength. The functional reliability of the designed elements was validated in two different genetic contexts. The designed parts were successfully utilized to improve the expression of BmK1 peptide toxin and fine-tune deoxy-xylulose phosphate pathway in Escherichia coli. Our results demonstrate that the methodology based on ANN model can de novo and quantitatively design regulatory elements with desired strengths, which are of great importance for synthetic biology applications. PMID:23560087

Meng, Hailin; Wang, Jianfeng; Xiong, Zhiqiang; Xu, Feng; Zhao, Guoping; Wang, Yong

2013-04-01

409

High-precision isotopic characterization of USGS reference materials by TIMS and MC-ICP-MS  

NASA Astrophysics Data System (ADS)

The Pacific Centre for Isotopic and Geochemical Research (PCIGR) at the University of British Columbia has undertaken a systematic analysis of the isotopic (Sr, Nd, and Pb) compositions and concentrations of a broad compositional range of U.S. Geological Survey (USGS) reference materials, including basalt (BCR-1, 2; BHVO-1, 2), andesite (AGV-1, 2), rhyolite (RGM-1, 2), syenite (STM-1, 2), granodiorite (GSP-2), and granite (G-2, 3). USGS rock reference materials are geochemically well characterized, but there is neither a systematic methodology nor a database for radiogenic isotopic compositions, even for the widely used BCR-1. This investigation represents the first comprehensive, systematic analysis of the isotopic composition and concentration of USGS reference materials and provides an important database for the isotopic community. In addition, the range of equipment at the PCIGR, including a Nu Instruments Plasma MC-ICP-MS, a Thermo Finnigan Triton TIMS, and a Thermo Finnigan Element2 HR-ICP-MS, permits an assessment and comparison of the precision and accuracy of isotopic analyses determined by both the TIMS and MC-ICP-MS methods (e.g., Nd isotopic compositions). For each of the reference materials, 5 to 10 complete replicate analyses provide coherent isotopic results, all with external precision below 30 ppm (2 SD) for Sr and Nd isotopic compositions (27 and 24 ppm for TIMS and MC-ICP-MS, respectively). Our results also show that the first- and second-generation USGS reference materials have homogeneous Sr and Nd isotopic compositions. Nd isotopic compositions by MC-ICP-MS and TIMS agree to within 15 ppm for all reference materials. Interlaboratory MC-ICP-MS comparisons show excellent agreement for Pb isotopic compositions; however, the reproducibility is not as good as for Sr and Nd. A careful, sequential leaching experiment of three first- and second-generation reference materials (BCR, BHVO, AGV) indicates that the heterogeneity in Pb isotopic compositions, and concentrations, could be directly related to contamination by the steel (mortar/pestle) used to process the materials. Contamination also accounts for the high concentrations of certain other trace elements (e.g., Li, Mo, Cd, Sn, Sb, W) in various USGS reference materials.

Weis, Dominique; Kieffer, Bruno; Maerschalk, Claude; Barling, Jane; de Jong, Jeroen; Williams, Gwen A.; Hanano, Diane; Pretorius, Wilma; Mattielli, Nadine; Scoates, James S.; Goolaerts, Arnaud; Friedman, Richard M.; Mahoney, J. Brian

2006-08-01

410

Electron drift time in silicon drift detectors: A technique for high precision measurement of electron drift mobility  

Microsoft Academic Search

This paper presents a precise absolute measurement of the drift velocity and mobility of electrons in high resistivity silicon at room temperature. The electron velocity is obtained from the differential measurement of the drift time of an electron cloud in a silicon drift detector. The main features of the transport scheme of this class of detectors are: the high uniformity

A. Castoldi; P. Rehak

1995-01-01

411

Large stroke and high precision pneumatic–piezoelectric hybrid positioning control using adaptive discrete variable structure control  

Microsoft Academic Search

This paper investigates a novel large stroke and high precision pneumatic–piezoelectric hybrid positioning control system that contains a pneumatic servo cylinder and a piezoelectric servo actuator combined in cascade. The pneumatic servo cylinder serves to positioning with high speed and large stroke; the piezoelectric actuator positions in fine stroke for compensating the influence of friction force so as to achieve

Mao-Hsiung Chiang; Chung-Chieh Chen; Tan-Ni Tsou

2005-01-01

412

Fabrication and Metrology of High-Precision Foil Mirror Mounting Elements.  

National Technical Information Service (NTIS)

During the period of this Cooperative Agreement, MIT (Massachusetts Institute of Technology) developed advanced methods for applying silicon microstructures for the precision assembly of foil x-ray optics in support of the Constellation-X Spectroscopy X-r...

M. L. Schattenburg

2002-01-01

413

Evidence of 11-year solar cycles in tree rings from 1010 to 1110 AD – Progress on high precision AMS measurements  

NASA Astrophysics Data System (ADS)

Oak tree rings from Southern Germany covering the AD 1010–1110 years have been analyzed for radiocarbon with accelerator mass spectrometry (AMS) at the laboratory at ETH Zurich. High-precision measurements with a precision down to 12 years radiocarbon age and a time resolution of 2 years aimed to identify modulations of the 14C concentration in tree ring samples caused by the 11 years solar cycles, a feature that so far is not visible in the IntCal calibration curve. Our results are in good agreement with the current calibration curve IntCal09. However, we observed an offset in radiocarbon age of 25–40 years towards older values. An evaluation of our sample preparation, that included variations of e.g.: chemicals, test glasses and processing steps did not explain this offset. The numerous measurements using the AMS-MICADAS system validated its suitability for high precision measurements with high repeatability.

Güttler, D.; Wacker, L.; Kromer, B.; Friedrich, M.; Synal, H.-A.

2013-01-01

414

High precision determination of bromine isotope ratio by GC-MC-ICPMS  

NASA Astrophysics Data System (ADS)

This work presents a new methodology for the precise determination of bromine isotope ratio in individual organic compounds based on the simultaneous introduction of brominated organic compounds and strontium as an external spike into MC-ICPMS. Using the proposed methodology, an external precision (2[sigma]) up to 0.1[per mille sign] has been attained. The new approach for the bromine isotope ratio analysis could be applied for the investigating the fate of the organobromine compounds in the environment.

Gelman, Faina; Halicz, Ludwik

2010-01-01

415

Precision control of high temperature furnaces using an auxiliary power supply and charged particle current flow  

DOEpatents

Two power supplies are combined to control a furnace. A main power supply heats the furnace in the traditional manner, while the power from the auxiliary supply is introduced as a current flow through charged particles existing due to ionized gas or thermionic emission. The main power supply provides the bulk heating power and the auxiliary supply provides a precise and fast power source such that the precision of the total power delivered to the furnace is improved. 5 figs.

Pollock, G.G.

1997-01-28

416

High-precision characterization of textured a-Si:H/SnO2:F structures by spectroscopic ellipsometry  

NASA Astrophysics Data System (ADS)

Spectroscopic ellipsometry (SE) has been applied for the characterization of hydrogenated amorphous silicon (a-Si:H) layers formed on SnO2:F textured structures in an attempt to establish the structural characterization method for a-Si:H solar cells. In particular, an optical model that allows the complete evaluation of microscopically non-uniform a-Si:H/SnO2:F textured structures has been developed for the SE analysis. In order to express the complicated optical response in the textured structures, the optical model incorporates (i) the surface roughness and interface layers calculated using an effective-medium-approximation multilayer model and (ii) the a-Si:H/SnO2:F structure divided into two regions with different thicknesses. Using this optical model, SE spectra obtained experimentally from the a-Si:H/SnO2:F textured structure can be reproduced almost perfectly. The a-Si:H/SnO2:F structure deduced from the SE analysis shows remarkable agreement with that observed from transmission electron microscopy. Moreover, a variety of a-Si:H layers with different thicknesses are expressed from the identical optical model. The SE analysis method developed in this study can be utilized further to perform high-precision and non-destructive characterization of various a-Si:H layers incorporated in large-area a-Si:H modules.

Akagawa, Masataka; Fujiwara, Hiroyuki

2011-10-01

417

High-precision {beta} decay half-life measurements of proton-rich nuclei for testing the CVC hypothesis  

SciTech Connect

The experimental study of super-allowed nuclear {beta} decays serves as a sensitive probe of the conservation of the weak vector current (CVC) and allows tight limits to be set on the presence of scalar or right-handed currents. Once CVC is verified, it is possible to determine the V{sub ud} element of the CKM quark-mixing matrix. Similarly, the study of nuclear mirror {beta} decays allows to arrive at the same final quantity V{sub ud}. Whereas dedicated studies of 0{sup +}{yields}0{sup +} decays are performed for several decades now, the potential of mirror transitions was only rediscovered recently. Therefore, it can be expected that important progress is possible with high-precision studies of different mirror {beta} decays. In the present piece of work the half-life measurements performed by the CENBG group of the proton-rich nuclei {sup 42}Ti, {sup 38-39}Ca, {sup 30-31}S and {sup 29}P are summarised.

Kurtukian-Nieto, T. [Centre d'Etudes Nucleaires de Bordeaux-Gradignan (CENBG), Universite Bordeaux 1, CNRS/IN2P3, Chemin du Solarium, BP 120, F-33175 Gradignan cedex (France); Collaboration: NEX Group of CENBG

2011-11-30

418

High resolution and high precision on line isotopic analysis of Holocene and glacial ice performed in the field  

NASA Astrophysics Data System (ADS)

Ice core records as obtained from polar ice caps provide a wealth of paleoclimatic information. One of the main features of ice cores is their potential for high temporal resolution. The isotopic signature of the ice, expressed through the relative abundances of the two heavy isotopologues H218O and HD16O, is a widely used proxy for the reconstruction of past temperature and accumulation. One step further the combined information obtained from these two isotopologues, commonly referred to as the deuterium excess, can be utilized to infer additional information about the source of the precipitated moisture. Until very recently isotopic analysis of polar ice was performed with isotope Ratio Mass Spectrometry (IRMS) in a discrete fashion resulting in a high workload related to the preparation of samples. Most important though the available temporal resolution of the ice core was in many cases not fully exploited. In order to overcome these limitations we have developed a system that interfaces a commercially available IR laser cavity ring-down spectrometer tailored for water isotope analysis to a stream of liquid water as extracted from a continuously melted ice rod. The system offers the possibility for simultaneous ?18O and ?D analysis with a sample requirement of approximately 0.1 ml/min. The system has been deployed in the field during the NEEM ice core drilling project on 2009 and 2010. In this study we present actual on line measurements of Holocene and glacial ice. We also discuss how parameters as the melt rate, acquisition rate and integration time affect the obtained precision and resolution and we describe data analysis techniques that can improve these last two parameters. By applying spectral methods we are able to quantify the smoothing effects imposed by diffusion of the sample in the sample transfer lines and the optical cavity of the instrument. We demonstrate that with an acquisition rate of 0.2 Hz we are able to obtain a precision of 0.5‰ and 0.15‰ for ?D and ?18O respectively. This is comparable to the performance of traditional IRMS systems for ?D but slightly less precise for ?18O. With this acquisition rate the system’s 3db bandwidth is 0.006 Hz. With a melt rate equal to 3 cm/min, the latter translates to signals with wavelengths of 8.3 cm. We will comment on the quality of the acquired ice core data and their potential use for dating, paleotemperature reconstruction, isotopic firn diffusion and deuterium excess studies.

Gkinis, V.; Popp, T. J.; Johnsen, S. J.; Blunier, T.; Bigler, M.; Stowasser, C.; Schüpbach, S.; Leuenberger, D.

2010-12-01

419

HIGH-PRECISION TIMING OF FIVE MILLISECOND PULSARS: SPACE VELOCITIES, BINARY EVOLUTION, AND EQUIVALENCE PRINCIPLES  

SciTech Connect

We present high-precision timing of five millisecond pulsars (MSPs) carried out for more than seven years; four pulsars are in binary systems and one is isolated. We are able to measure the pulsars' proper motions and derive an estimate for their space velocities. The measured two-dimensional velocities are in the range 70-210 km s{sup -1}, consistent with those measured for other MSPs. We also use all the available proper motion information for isolated and binary MSPs to update the known velocity distribution for these populations. As found by earlier works, we find that the velocity distribution of binary and isolated MSPs are indistinguishable with the current data. Four of the pulsars in our observing program are highly recycled with low-mass white dwarf companions and we are able to derive accurate binary parameters for these systems. For three of these binary systems, we are able to place initial constraints on the pulsar masses with best-fit values in the range 1.0-1.6 M{sub Sun }. The implications of the results presented here to our understanding of binary pulsar evolution are discussed. The updated parameters for the binary systems studied here, together with recently discovered similar systems, allowed us to update previous limits on the violation of the strong equivalence principle through the parameter |{Delta}| to 4.6 Multiplication-Sign 10{sup -3} (95% confidence) and the violation of Lorentz invariance/momentum conservation through the parameter |{alpha}-hat3| to 5.5 Multiplication-Sign 10{sup -20} (95% confidence).

Gonzalez, M. E.; Stairs, I. H. [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1 (Canada); Ferdman, R. D.; Lyne, A. G. [Jodrell Bank Centre for Astrophysics, University of Manchester, Manchester, M13 9PL (United Kingdom); Freire, P. C. C.; Kramer, M. [Max-Planck-Institut fuer Radioastronomie, D-53121 Bonn (Germany); Nice, D. J. [Physics Department, Lafayette College, Easton, PA 18042 (United States); Demorest, P. B.; Ransom, S. M. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); Camilo, F. [Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027 (United States); Hobbs, G.; Manchester, R. N., E-mail: gonzalez@phas.ubc.ca1 [Australia Telescope National Facility, CSIRO, Epping, NSW 1710 (Australia)

2011-12-20

420

Atmospheric turbulence and high-precision ground-based solar polarimetry  

NASA Astrophysics Data System (ADS)

High-precision full-Stokes polarimetry at near diffraction limited spatial resolution is important to understand numerous physical processes on the Sun. In view of the next generation of ground based solar telescopes, we have explored, through numerical simulation, how polarimetric accuracy is affected by atmospheric seeing, especially in the case of large aperture telescopes with increasing ratio between mirror diameter and Fried parameter. In this work we focus on higher-order wavefront aberrations. The numerical generation of time-dependent turbulence phase screens is based on the well-known power spectral method and on the assumption that the temporal evolution is mainly caused by wind driven propagation of frozen-in turbulence across the telescope. To analyze the seeing induced cross-talk between the Stokes parameters we consider polarization modulation scheme based on a continuously rotating waveplate with rotation frequencies between 1 Hz and several 100 Hz. Further, we have started the development of a new fast solar imaging polarimeter, based on pnCCD detector technology from PNSensor. The first detector will have a size of 264 x 264 pixels and will work at frame rates of up to 1kHz, combined with a very low readout noise of 2-3 e- ENC. The camera readout electronics will allow for buffering and accumulation of images corresponding to the different phases of the fast polarization modulation. A high write-out rate (about 30 to 50 frames/s) will allow for post-facto image reconstruction. We will present the concept and the expected performance of the new polarimeter, based on the above-mentioned simulations of atmospheric seeing.

Nagaraju, K.; Feller, A.; Ihle, S.; Soltau, H.

2011-09-01

421

SpecTrap: precision spectroscopy of highly charged ions—status and prospects  

NASA Astrophysics Data System (ADS)

We present the status of the SpecTrap experiment currently being commissioned in the framework of the HITRAP project at GSI, Darmstadt, Germany. SpecTrap is a cryogenic Penning trap experiment dedicated to high-accuracy laser spectroscopy of highly charged ions (HCI) near rest. Determination of fine structure and hyperfine structure splittings in HCI with an expected relative spectral resolution of 10-7 will offer the possibility to test quantum electrodynamics in strong fields with unprecedented accuracy. Recently, we have demonstrated trapping and laser Doppler cooling of singly charged magnesium ions in SpecTrap. We report on the status of the experimental apparatus, measurements and present the future program toward storage and cooling of HCI.

Murböck, Tobias; Albrecht, Sebastian; Andelkovic, Zoran; Cazan, Radu; Hannen, Volker; Jöhren, Raphael; Vollbrecht, Jonas; Schmidt, Stefan; Segal, Danny; Thompson, Richard; Vogel, Manuel; Weinheimer, Christian; Nörtershäuser, Wilfried; Birkl, Gerhard

2013-09-01

422

High Precision Measurements of 235U/238U Isotopic Fractionations Resulting From Uranium Reduction Induced by Zero Valent Iron  

NASA Astrophysics Data System (ADS)

Uranium is a widespread natural and anthropogenic contaminant in surface and subsurface waters. Like several other inorganic contaminants, uranium is mobile under oxidizing conditions but may be immobilized by chemical reduction. U(VI) moves with groundwater as (UO2)2+ and as soluble complexes with carbonate, phosphate, and fluoride. In many groundwater systems, uranium undergoes chemical reduction to U(IV), which is insoluble and immobile. Therefore, understanding the extent of reduction is essential for predicting the mobility of uranium in groundwater. Mass dependent isotopic fractionations of redox sensitive contaminants frequently found in groundwater (including chromate, selenate, and nitrate) have proven exceptionally useful for estimating the rate and extent of reduction and immobilization. Until recently, however, analytical limitations have prevented these techniques from being applied to heavier redox sensitive elements, such as uranium. The advent of highly sensitive multi-collector inductively coupled plasma mass spectrometers (MC-ICP-MS) enables high precision measurements of previously undetected variations in many elements. Laboratory reduction experiments with zero valent iron (ZVI) were performed in a controlled environment to test the hypothesis that uranium isotopes, specifically 235U/238U, behave similarly to other redox sensitive contaminants and produce a mass dependent fractionation during the transformation between valence states. Because of the large abundance differences between 235U and 238U, initial experiments used U500, an enriched uranium standard with approximately equal parts 235U and 238U. Results suggest that the highly sensitive MC-ICP-MS distinguishes 235U/238Uvariations to approximately + 0.02per mil. Measured isotopic fractionations between the 235U/238U of the initial and final experimental solutions (~70% reduced) are approximately 1.1 per mil, and increase with decreasing concentration. Measured variations in 235U/238U suggest that uranium isotopic ratios could also prove to be valuable indicators of contaminant immobilization and paleoenvironmental conditions.

Rademacher, L.; Lundstrom, C.; Johnson, T.

2003-12-01

423

Development of a Fast, High-Precision Analyzer for N2O and CO Measurements in Field Applications  

NASA Astrophysics Data System (ADS)

Accurate and precise measurements of both nitrous oxide and carbon monoxide concentrations are important in understanding global atmospheric chemistry. Because atmospheric mixing ratios of these species are small ( < 0.5 PPM), an analyzer designed to probe these species must have high sensitivity and high precision to make meaningful measurements. We report here the development of an analyzer based on our patented off-axis integrated cavity output spectroscopy (Off-Axis ICOS) which measures both CO and N2O concentrations with a 1-sigma precision of less than 0.3 ppb in 1 second. Without calibration the instrument is accurate to better than 1% over the temperature range of 15- 35C. Data rates of up to 10 Hz are achieved to allow for eddy flux correlation measurements. The instrument is low-power (~150 watts) and requires no liquid nitrogen, allowing for easy measurements in the field.

Provencal, Robert; Fellers, Raymond; Owano, Thomas; He, Yonggang; Baer, Doug

2010-05-01

424

High precision methods for locating the celestial intermediate pole and origin  

NASA Astrophysics Data System (ADS)

Context: .The precession-nutation transformation describes the changing directions on the celestial sphere of the Earth's pole and an adopted origin of right ascension. The coordinate system for the celestial sphere is the geocentric celestial reference system, and the two directions are the celestial intermediate pole (CIP) and the celestial intermediate origin (CIO), the latter having supplanted the equinox for this purpose following IAU resolutions in 2000. The celestial coordinate triad based on the CIP and CIO is called the celestial intermediate reference system; the prediction of topocentric directions additionally requires the Earth rotation angle (ERA), the counterpart of Greenwich sidereal time (GST) in the former equinox based system. Aims: .The purpose of this paper is to review the different ways of calculating the CIP and CIO directions to precisions of a few microarcseconds over a time span of several centuries, meeting the requirements of high-accuracy applications. Methods: .Various implementations are described, their theoretical bases compared and the relationships between the expressions for the relevant parameters are provided. Semi-analytical and numerical comparisons have been made, based on the P03 precession and the IAU 2000A nutation, with slight modifications to the latter to make it consistent with P03. Results: .We have identified which transformations between celestial and terrestrial coordinates involve a minimum number of variables and coefficients for given accuracy objectives. The various methods are consistent at the level of a few microarcseconds over several centuries, and equal accuracy is achievable using both the equinox/GST paradigm and the CIO/ERA paradigm. Given existing nutation models, the most concise expressions for locating the CIP are based on the Fukushima-Williams bias-precession-nutation angles. The CIO can be located to a few microarcseconds using the CIO locator s. The equation of the origins (EO) is sensitive to the precession-nutation, but can locate the CIO to a few microarcseconds as long as consistent models are used for EO and precession-nutation.

Capitaine, N.; Wallace, P. T.

2006-05-01

425

Precise High-cadence Time Series Observations of Five Variable Young Stars in Auriga with MOST  

NASA Astrophysics Data System (ADS)

To explore young star variability on a large range of timescales, we have used the MOST satellite to obtain 24 days of continuous, sub-minute cadence, high-precision optical photometry on a field of classical and weak-lined T Tauri stars (TTSs) in the Taurus-Auriga star formation complex. Observations of AB Aurigae, SU Aurigae, V396 Aurigae, V397 Aurigae, and HD 31305 reveal brightness fluctuations at the 1%-10% level on timescales of hours to weeks. We have further assessed the variability properties with Fourier, wavelet, and autocorrelation techniques, identifying one significant period per star. We present spot models in an attempt to fit the periodicities, but find that we cannot fully account for the observed variability. Rather, all stars exhibit a mixture of periodic and aperiodic behavior, with the latter dominating stochastically on timescales less than several days. After removal of the main periodicity, periodograms for each light curve display power-law trends consistent with those seen for other young accreting stars. Several of our targets exhibited unusual variability patterns not anticipated by prior studies, and we propose that this behavior originates with the circumstellar disks. The MOST observations underscore the need for investigation of TTS light variations on a wide range of timescales in order to elucidate the physical processes responsible; we provide guidelines for future time series observations. Based on data from the MOST satellite, a Canadian Space Agency mission, jointly operated by Systems Canada Inc. (MSCI), formerly part of Dynacon, Inc., the University of Toronto Institute for Aerospace Studies, and the University of British Columbia with the assistance of the University of Vienna.

Cody, Ann Marie; Tayar, Jamie; Hillenbrand, Lynne A.; Matthews, Jaymie M.; Kallinger, Thomas

2013-03-01

426

High-precision genetic mapping of behavioral traits in the diversity outbred mouse population  

PubMed Central

Historically our ability to identify genetic variants underlying complex behavioral traits in mice has been limited by low mapping resolution of conventional mouse crosses. The newly developed Diversity Outbred (DO) population promises to deliver improved resolution that will circumvent costly fine-mapping studies. The DO is derived from the same founder strains as the Collaborative Cross (CC), including three wild-derived strains. Thus the DO provides more allelic diversity and greater potential for discovery compared to crosses involving standard mouse strains. We have characterized 283 male and female DO mice using open-field, light–dark box, tail-suspension and visual-cliff avoidance tests to generate 38 behavioral measures. We identified several quantitative trait loci (QTL) for these traits with support intervals ranging from 1 to 3 Mb in size. These intervals contain relatively few genes (ranging from 5 to 96). For a majority of QTL, using the founder allelic effects together with whole genome sequence data, we could further narrow the positional candidates. Several QTL replicate previously published loci. Novel loci were also identified for anxiety- and activity-related traits. Half of the QTLs are associated with wild-derived alleles, confirming the value to behavioral genetics of added genetic diversity in the DO. In the presence of wild-alleles we sometimes observe behaviors that are qualitatively different from the expected response. Our results demonstrate that high-precision mapping of behavioral traits can be achieved with moderate numbers of DO animals, representing a significant advance in our ability to leverage the mouse as a tool for behavioral genetics

Logan, R W; Robledo, R F; Recla, J M; Philip, V M; Bubier, J A; Jay, J J; Harwood, C; Wilcox, T; Gatti, D M; Bult, C J; Churchill, G A; Chesler, E J

2013-01-01

427

A new device for high precision in situ sediment temperature profile measurements at the seafloor  

NASA Astrophysics Data System (ADS)

In situ sediment temperature profile measurements at the seafloor provide valuable information on fluid seepage, hydrate stability, and ambient temperature of samples. In addition, it can be convenient to approximate other parameters such as concentrations of porewater constituents from temperature or temperature gradient using transfer functions if their distribution is controlled by the same processes and direct quantification involves time-consuming sampling and laboratory analyses. We present a new instrument that can be used to obtain precisely positioned sediment temperature profile measurements from the seafloor during ROV dives. Consisting of a 0.4 m-long sensor rod equipped with eight temperature sensors and a standard data logger, the new T-Stick can be operated by an ROV in a fully autonomous mode. The temperature range of the instrument is -5 °C to 35 °C and it can withstand pressures of up to 600 bar. Compared to previously used instruments, the smaller diameter of the new T-Stick reduces the thermal inertia of the lance and results in shorter equilibration times. Virtual measurements generated by a numerical model showed that the T-Stick provides highly accurate temperature profile measurements with a root mean square error of 0.0027 K for a wide range of thermal sediment properties. Modeled temperature gradients are representative of both normal deep sea settings and cold seep environments with elevated temperature gradients of up to three orders of magnitude above normal background values, which are the primary target areas for T-Stick measurements. Deviations from the true in situ temperature profiles are caused by disturbance of the temperature field by the probe itself and may lead to underestimation of gradients and curvature in the profiles. A first field test of the T-Stick was conducted at the Håkon Mosby mud volcano at 1250 m water depth on the Barents Sea slope, where the new instrument provided useful information about the origin and extent of freshly erupted mud.