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1

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, (2)…

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

2

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

3

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

4

High precision laser forming for microactuation  

NASA Astrophysics Data System (ADS)

For assembly of micro-devices, such as photonic devices, the precision alignment of components is often critical for their performance. Laser forming, also known as laser-adjusting, can be used to create an integrated microactuator to align the components with sub-micron precision after bonding. In this paper a so-called three-bridge planar manipulator was used to study the laser-material interaction and thermal and mechanical behavior of the laser forming mechanism. A 3-D Finite Element Method (FEM) model and experiments are used to identify the optimal parameter settings for a high precision actuator. The goal in this paper is to investigate how precise the maximum occurring temperature and the resulting displacement are predicted by a 3-D FEM model by comparing with experimental results. A secondary goal is to investigate the resolution of the mechanism and the range of motion. With the experimental setup we measure the displacement and surface temperature in real-time. The time-dependent heat transfer FEM models match closely with experimental results, however the structural model can deviate more than 100% in absolute displacement. Experimentally, a positioning resolution of 0.1?m was achieved, with a total stroke exceeding 20?m. A spread of 10% in the temperature cycles between several experiments was found, which was attributed to a spread in the surface absorptivity. Combined with geometric tolerances, the spread in displacement can be as large as 20%. This implies that feedback control of the laser power, in combination with iterative learning during positioning, is required for high precision alignment. Even though the FEM models deviate substantially from the experiments, the 3-D FEM model predicts the trend in deformation sufficiently accurate to use it for design optimization of high precision 3-D actuators using laser adjusting.

Folkersma, Ger K. G. P.; Römer, G. R. B. E.; Brouwer, D. M.; Huis in't Veld, A. J.

2014-03-01

5

High precision redundant robotic manipulator  

DOEpatents

A high precision redundant robotic manipulator for overcoming contents imposed by obstacles or imposed by a highly congested work space is disclosed. One embodiment of the manipulator has four degrees of freedom and another embodiment has seven degrees of freedom. Each of the embodiments utilize a first selective compliant assembly robot arm (SCARA) configuration to provide high stiffness in the vertical plane, a second SCARA configuration to provide high stiffness in the horizontal plane. The seven degree of freedom embodiment also utilizes kinematic redundancy to provide the capability of avoiding obstacles that lie between the base of the manipulator and the end effector or link of the manipulator. These additional three degrees of freedom are added at the wrist link of the manipulator to provide pitch, yaw and roll. The seven degrees of freedom embodiment uses one revolute point per degree of freedom. For each of the revolute joints, a harmonic gear coupled to an electric motor is introduced, and together with properly designed based servo controllers provide an end point repeatability of less than 10 microns. 3 figs.

Young, K.K.D.

1998-09-22

6

High precision redundant robotic manipulator  

DOEpatents

A high precision redundant robotic manipulator for overcoming contents imposed by obstacles or imposed by a highly congested work space. One embodiment of the manipulator has four degrees of freedom and another embodiment has seven degreed of freedom. Each of the embodiments utilize a first selective compliant assembly robot arm (SCARA) configuration to provide high stiffness in the vertical plane, a second SCARA configuration to provide high stiffness in the horizontal plane. The seven degree of freedom embodiment also utilizes kinematic redundancy to provide the capability of avoiding obstacles that lie between the base of the manipulator and the end effector or link of the manipulator. These additional three degrees of freedom are added at the wrist link of the manipulator to provide pitch, yaw and roll. The seven degrees of freedom embodiment uses one revolute point per degree of freedom. For each of the revolute joints, a harmonic gear coupled to an electric motor is introduced, and together with properly designed based servo controllers provide an end point repeatability of less than 10 microns.

Young, Kar-Keung David (Mountain View, CA)

1998-01-01

7

High precision pressure measurement with a funnel  

NASA Astrophysics Data System (ADS)

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 placed, upside down, in a container filled with distilled water, placed on a scale. Our method provides a theoretical precision for the pressure measurement of the order of 0.01 Pa. Beyond this, the advantage of this method relies on the simplicity of the materials used and on the opportunity to discuss, at an undergraduate level, basic concepts regarding all those phenomena in which low or very low differential pressures are relevant.

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

2008-11-01

8

High precision anatomy for MEG.  

PubMed

Precise MEG estimates of neuronal current flow are undermined by uncertain knowledge of the head location with respect to the MEG sensors. This is either due to head movements within the scanning session or systematic errors in co-registration to anatomy. Here we show how such errors can be minimized using subject-specific head-casts produced using 3D printing technology. The casts fit the scalp of the subject internally and the inside of the MEG dewar externally, reducing within session and between session head movements. Systematic errors in matching to MRI coordinate system are also reduced through the use of MRI-visible fiducial markers placed on the same cast. Bootstrap estimates of absolute co-registration error were of the order of 1mm. Estimates of relative co-registration error were <1.5mm between sessions. We corroborated these scalp based estimates by looking at the MEG data recorded over a 6month period. We found that the between session sensor variability of the subject's evoked response was of the order of the within session noise, showing no appreciable noise due to between-session movement. Simulations suggest that the between-session sensor level amplitude SNR improved by a factor of 5 over conventional strategies. We show that at this level of coregistration accuracy there is strong evidence for anatomical models based on the individual rather than canonical anatomy; but that this advantage disappears for errors of greater than 5mm. This work paves the way for source reconstruction methods which can exploit very high SNR signals and accurate anatomical models; and also significantly increases the sensitivity of longitudinal studies with MEG. PMID:23911673

Troebinger, Luzia; López, José David; Lutti, Antoine; Bradbury, David; Bestmann, Sven; Barnes, Gareth

2014-02-01

9

High precision anatomy for MEG?  

PubMed Central

Precise MEG estimates of neuronal current flow are undermined by uncertain knowledge of the head location with respect to the MEG sensors. This is either due to head movements within the scanning session or systematic errors in co-registration to anatomy. Here we show how such errors can be minimized using subject-specific head-casts produced using 3D printing technology. The casts fit the scalp of the subject internally and the inside of the MEG dewar externally, reducing within session and between session head movements. Systematic errors in matching to MRI coordinate system are also reduced through the use of MRI-visible fiducial markers placed on the same cast. Bootstrap estimates of absolute co-registration error were of the order of 1 mm. Estimates of relative co-registration error were < 1.5 mm between sessions. We corroborated these scalp based estimates by looking at the MEG data recorded over a 6 month period. We found that the between session sensor variability of the subject's evoked response was of the order of the within session noise, showing no appreciable noise due to between-session movement. Simulations suggest that the between-session sensor level amplitude SNR improved by a factor of 5 over conventional strategies. We show that at this level of coregistration accuracy there is strong evidence for anatomical models based on the individual rather than canonical anatomy; but that this advantage disappears for errors of greater than 5 mm. This work paves the way for source reconstruction methods which can exploit very high SNR signals and accurate anatomical models; and also significantly increases the sensitivity of longitudinal studies with MEG. PMID:23911673

Troebinger, Luzia; Lopez, Jose David; Lutti, Antoine; Bradbury, David; Bestmann, Sven; Barnes, Gareth

2014-01-01

10

High-precision multipass reflectometer  

SciTech Connect

The multipass reflectometer has been shown to be a convenient and precise instrument for the measurement of spectral reflectances in excess of 0.99. This report gives a brief sketch of the initial setup of the reflectometer, its operation, optimization of parameters, and some limitations to the expected precision. The instrumental precision is set by the uncertainty in the computer fit of a straight line to the measured data. Systematic errors due to nonuniform photosurfaces and the effects of astigmatism have been minimized. We have used this reflectrometer to measure the absolute reflectance of evaporated aluminum films in the uv and visible regions. It has also been used to measure the low-level insertion losses of laser window materials for this same spectral region.

Edwards, D.F.; Baumeister, P.

1981-01-01

11

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

12

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-D¯0 mixing, with incredible precision.

Magnin, J.

2009-04-01

13

Precision Crystal Calorimeters in High Energy Physics  

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.

Ren-Yuan Zhu

2010-01-08

14

High-rate precise point positioning (PPP) to measure seismic wave motions: an experimental comparison of GPS PPP with inertial measurement units  

NASA Astrophysics Data System (ADS)

High-rate GPS has been widely used to construct displacement waveforms and to invert for source parameters of earthquakes. Almost all works on internal and external evaluation of high-rate GPS accuracy are based on GPS relative positioning. We build an experimental platform to externally evaluate the accuracy of 50-Hz PPP displacement waveforms. Since the shake table allows motion in any of six degrees of freedom, we install an inertial measurement unit (IMU) to measure the attitude of the platform and transform the IMU displacements into the GPS coordinate system. The experimental results have shown that high-rate PPP can produce absolute horizontal displacement waveforms at the accuracy of 2-4 mm and absolute vertical displacement waveforms at the sub-centimeter level of accuracy within a short period of time. The significance of the experiments indicates that high-rate PPP is capable of detecting absolute seismic displacement waveforms at the same high accuracy as GPS relative positioning techniques, but requires no fixed datum station. We have also found a small scaling error of IMU and a small time offset of misalignment between high-rate PPP and IMU displacement waveforms by comparing the amplitudes of and cross-correlating both the displacement waveforms.

Xu, Peiliang; Shi, Chuang; Fang, Rongxin; Liu, Jingnan; Niu, Xiaoji; Zhang, Quan; Yanagidani, Takashi

2013-04-01

15

High-rate precise point positioning (PPP) to measure seismic wave motions: An experimental comparison of GPS PPP with inertial measurement units  

NASA Astrophysics Data System (ADS)

High-rate GPS has been widely used to construct displacement waveforms and to invert for source parameters of earthquakes. Almost all works on internal and external evaluation of high-rate GPS accuracy are based on GPS relative positioning. We build an experimental platform to externally evaluate the accuracy of 50 Hz PPP displacement waveforms. Since the shake table allows motion in any of six degrees of freedom, we install an inertial measurement unit (IMU) to measure the attitude of the platform and transform the IMU displacements into the GPS coordinate system. The experimental results have shown that high-rate PPP can produce absolute horizontal displacement waveforms at the accuracy of 2 to 4 millimeters and absolute vertical displacement waveforms at the sub-centimeter level of accuracy within a short period of time. The significance of the experiments indicates that high-rate PPP is capable of detecting absolute seismic displacement waveforms at the same high accuracy as GPS relative positioning techniques but requires no fixed datum station. We have also found a small scaling error of IMU and a small time offset of misalignment between high-rate PPP and IMU displacement waveforms by comparing the amplitudes of and cross-correlating both the displacement waveforms. For more details on this talk, one can now get access to the on-line-first version of our Journal of Geodesy paper: J Geod, DOI 10.1007/s00190-012-0606-z

Xu, Peiliang; Shi, Chuang; Fang, Rongxin; Liu, Jingnan; Niu, Xiaoji; Zhang, Quan; Yanagidani, Takashi

2013-04-01

16

Digitalization of highly precise fluxgate magnetometers  

Microsoft Academic Search

This paper describes the theory behind all three known ways of digitalizing the fluxgate magnetometers: analogue magnetometers with digitalized output using high resolution ADC, application of the delta–sigma modulation to the sensor feedback loop and fully digital signal detection. At present time the ?–? ADCs are mostly used for the digitalization of the highly precise fluxgate magnetometers. The relevant part

A. Cerman; A. Kuna; P. Ripka; J. M. G. Merayo

2005-01-01

17

High precision measurements in crustal dynamic studies  

NASA Technical Reports Server (NTRS)

The development of high-precision instrumentation for monitoring benchmark stability and evaluating coseismic strain and tilt signals is reviewed. Laser strainmeter and tilt observations are presented. Examples of coseismic deformation in several geographic locations are given. Evidence suggests that the Earth undergoes elastic response to abrupt faulting.

Wyatt, F.; Berger, J.

1984-01-01

18

High bandwidth control of precision motion instrumentation.  

PubMed

This article presents a high-bandwidth control design suitable for precision motion instrumentation. Iterative learning control (ILC), a feedforward technique that uses previous iterations of the desired trajectory, is used to leverage the repetition that occurs in many tasks, such as raster scanning in microscopy. Two ILC designs are presented. The first design uses the motion system dynamic model to maximize bandwidth. The second design uses a time-varying bandwidth that is particularly useful for nonsmooth trajectories such as raster scanning. Both designs are applied to a multiaxis piezoelectric-actuated flexure system and evaluated on a nonsmooth trajectory. The ILC designs demonstrate significant bandwidth and precision improvements over the feedback controller, and the ability to achieve precision motion control at frequencies higher than multiple system resonances. PMID:19044716

Bristow, Douglas A; Dong, Jingyan; Alleyne, Andrew G; Ferreira, Placid; Salapaka, Srinivas

2008-10-01

19

High bandwidth control of precision motion instrumentation  

NASA Astrophysics Data System (ADS)

This article presents a high-bandwidth control design suitable for precision motion instrumentation. Iterative learning control (ILC), a feedforward technique that uses previous iterations of the desired trajectory, is used to leverage the repetition that occurs in many tasks, such as raster scanning in microscopy. Two ILC designs are presented. The first design uses the motion system dynamic model to maximize bandwidth. The second design uses a time-varying bandwidth that is particularly useful for nonsmooth trajectories such as raster scanning. Both designs are applied to a multiaxis piezoelectric-actuated flexure system and evaluated on a nonsmooth trajectory. The ILC designs demonstrate significant bandwidth and precision improvements over the feedback controller, and the ability to achieve precision motion control at frequencies higher than multiple system resonances.

Bristow, Douglas A.; Dong, Jingyan; Alleyne, Andrew G.; Ferreira, Placid; Salapaka, Srinivas

2008-10-01

20

High Precision Position Control Using an Adaptive Friction Compensation Approach  

Microsoft Academic Search

The presented work concerns the development of a trajectory tracking controller which is able to improve clearly the dynamical performance of a high precision positioning stage. Experiments in the pre-rolling and rolling friction regimes are conducted and a hybrid parameter estimation algorithm is used to fit the parameters of a simple dynamic friction model based on experimental data. Further experiments

Arvid Amthor; Stephan Zschaeck; Christoph Ament

2010-01-01

21

High precision voltage-to-frequency converter  

Microsoft Academic Search

A bipolar high precision voltage-to-frequency converter is described. The circuit includes an input voltage-to-current conversion stage followed by current-controlled multivibrator. The multivibrator trigger includes a window comparator with a limiter of the output voltage swing, and the timing capacitor discharge current is switched simultaneously with the window comparator bias. This allows to obtain high resolution near both trigger thresholds. The

Sidong Cai; I. M. Filanovsky

1994-01-01

22

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

23

Fiber Scrambling for High Precision Spectrographs  

NASA Astrophysics Data System (ADS)

The detection of Earth-like exoplanets with the radial velocity method requires extreme Doppler precision and long-term stability in order to measure tiny reflex velocities in the host star. Recent planet searches have led to the detection of so called "super-Earths” (up to a few Earth masses) that induce radial velocity changes of about 1 m/s. However, the detection of true Earth analogs requires a precision of 10 cm/s. One of the largest factors limiting Doppler precision is variation in the Point Spread Function (PSF) from observation to observation due to changes in the illumination of the slit and spectrograph optics. Thus, this stability has become a focus of current instrumentation work. Fiber optics have been used since the 1980's to couple telescopes to high-precision spectrographs, initially for simpler mechanical design and control. However, fiber optics are also naturally efficient scramblers. Scrambling refers to a fiber's ability to produce an output beam independent of input. Our research is focused on characterizing the scrambling properties of several types of fibers, including circular, square and octagonal fibers. By measuring the intensity distribution after the fiber as a function of input beam position, we can simulate guiding errors that occur at an observatory. Through this, we can determine which fibers produce the most uniform outputs for the severest guiding errors, improving the PSF and allowing sub-m/s precision. However, extensive testing of fibers of supposedly identical core diameter, length and shape from the same manufacturer has revealed the "personality” of individual fibers. Personality describes differing intensity patterns for supposedly duplicate fibers illuminated identically. Here, we present our results on scrambling characterization as a function of fiber type, while studying individual fiber personality.

Kaplan, Zachary; Spronck, J. F. P.; Fischer, D.

2011-05-01

24

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

25

High precision innovative micropump for artificial pancreas  

NASA Astrophysics Data System (ADS)

The concept of artificial pancreas, which comprises an insulin pump, a continuous glucose meter and a control algorithm, is a major step forward in managing patient with type 1 diabetes mellitus. The stability of the control algorithm is based on short-term precision micropump to deliver rapid-acting insulin and to specific integrated sensors able to monitor any failure leading to a loss of accuracy. Debiotech's MEMS micropump, based on the membrane pump principle, is made of a stack of 3 silicon wafers. The pumping chamber comprises a pillar check-valve at the inlet, a pumping membrane which is actuated against stop limiters by a piezo cantilever, an anti-free-flow outlet valve and a pressure sensor. The micropump inlet is tightly connected to the insulin reservoir while the outlet is in direct communication with the patient skin via a cannula. To meet the requirement of a pump dedicated to closed-loop application for diabetes care, in addition to the well-controlled displacement of the pumping membrane, the high precision of the micropump is based on specific actuation profiles that balance effect of pump elasticity in low-consumption push-pull mode.

Chappel, E.; Mefti, S.; Lettieri, G.-L.; Proennecke, S.; Conan, C.

2014-03-01

26

High precision beam alignment of electromagnetic wigglers  

SciTech Connect

The performance of Free-Electron Lasers depends critically on the quality of the alignment of the electron beam to the wiggler's magnetic axis and the deviation of this axis from a straight fine. The measurement of the electron beam position requires numerous beam position monitors in the wiggler, where space is at premium. The beam position measurement is used to set beam steerers for an orbit correction in the wiggler. The authors propose an alternative high precision alignment method in which one or two external Beam Position Monitors (BPM) are used. In this technique, the field in the electro-wiggler is modulated section by section and the beam position movement at the external BPM is detected in synchronism with the modulation. A beam offset at the modulated beam section will produce a modulation of the beam position at the detector that is a function of the of the beam offset and the absolute value of the modulation current. The wiggler errors produce a modulation that is a function of the modulation current. It will be shown that this method allows the detection and correction of the beam position at each section in the presence of wiggler errors with a good resolution. Furthermore, it allows one to measure the first and second integrals of the wiggler error over each wiggler section. Lastly, provided that wiggler sections can be degaussed effectively, one can test the deviation of the wiggler's magnetic axis from a straight line.

Ben-Zvi, I.; Qiu, X.Z.

1993-01-01

27

High-torque precision stepping drive  

NASA Technical Reports Server (NTRS)

Stepping drive has been designed for precise incremental angular positioning of scale models of spacecraft about a horizontal axis in order to accurately measure antenna receiving and transmitting characteristics. Positioning is insured by spring-loaded, self-locking plungers.

Kaspareck, W. E.

1968-01-01

28

High precision small angle generator for realization of the SI unit of plane angle and calibration of high precision autocollimators  

Microsoft Academic Search

A highly precise small angle generator (HPSAG) has been developed in UME to realize the SI unit of plane angle, radian (rad), more precisely and calibrate high precision autocollimators. The device can easily generate small angles in measurement steps of 0.001 arcsec in the measurement range of ±8 arcsec. This enables calibration of high-resolution electronic autocollimators in very small measurement

Tanfer Yandayan; Bulent Ozgur; Nuray Karaboce; Orhan Yaman

2012-01-01

29

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

E-print Network

High-precision camera distortion measurements with a "calibration harp" Z. Tang,1, R. Grompone von "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

Paris-Sud XI, Université de

30

Bootstrap tomography of high-precision pulses for quantum control  

E-print Network

Long-time dynamical decoupling and quantum control of qubits require high-precision control pulses. Full characterization (quantum tomography) of imperfect pulses presents a bootstrap problem: tomography requires initial states of a qubit which can not be prepared without imperfect pulses. We present a protocol for pulse error analysis, specifically tailored for a wide range of the single solid-state electron spins. Using a single electron spin of a nitrogen-vacancy (NV) center in diamond, we experimentally verify the correctness of the protocol, and demonstrate its usefulness for quantum control tasks.

V. V. Dobrovitski; G. de Lange; D. Ristè; R. Hanson

2010-04-19

31

Laser technology for high precision satellite tracking  

NASA Technical Reports Server (NTRS)

Fixed and mobile laser ranging stations have been developed to track satellites equipped with retro-reflector arrays. These have operated consistently at data rates of once per second with range precision better than 50 cm, using Q-switched ruby lasers with pulse durations of 20 to 40 nanoseconds. Improvements are being incorporated to improve the precision to 10 cm, and to permit ranging to more distant satellites. These include improved reflector array designs, processing and analysis of the received reflection pulses, and use of sub-nanosecond pulse duration lasers.

Plotkin, H. H.

1974-01-01

32

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

33

High-precision triangular-waveform generator  

DOEpatents

An ultra-linear ramp generator having separately programmable ascending and decending 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, T.R.

1981-11-14

34

High precision phase measurement technique for cell impedance spectroscopy  

NASA Astrophysics Data System (ADS)

This paper presents a new approach for high precision phase measurement. The new system is developed for biomedical applications such as complex cell impedance measurement and dielectric tissue analysis. In many of the named applications it is necessary to measure the complex dielectric constant of a sample as a function of frequency. Therefore the developed system is capable of measuring amplitude and especially high precision phase of the measurement signal over a wide frequency range from 10 Hz to 10 MHz. The experimental result of the new method shows a phase resolution of up to 0.01 degree at 1 MHz and 0.1 degree at 10 MHz. The excellent phase measurement resolution is achieved by a time transformation of the signal using a digital sampling circuitry. The functional principle of the digital sampling circuitry is based on Delta - Modulation and is implemented inside a cheap standard FPGA. The new system is successfully used in blood analysis applications and allows for a practical implementation of cost efficient capacitive hematocrit sensors for the first time.

Trebbels, Dennis; Woelki, Daniel; Zengerle, Roland

2010-04-01

35

High precision measurement of stellar radial velocity variations  

NASA Technical Reports Server (NTRS)

New techniques for the high precision measurement of variations in stellar radial velocities now allow a precision of better than 5 m/s to be obtained in routine telescopic observations. Some of the factors limiting velocity precision and how they can be overcome are discussed. Also presented are applications of these new techniques to the problems of detection of planetary systems around other stars and the use of stellar oscillations to determine interior properties of the stars.

Cochran, William D.; Hatzes, Artie P.

1990-01-01

36

High precision applications of the global positioning system  

NASA Technical Reports Server (NTRS)

The Global Positioning System (GPS) is a constellation of U.S. defense navigation satellites which can be used for military and civilian positioning applications. A wide variety of GPS scientific applications were identified and precise positioning capabilities with GPS were already demonstrated with data available from the present partial satellite constellation. Expected applications include: measurements of Earth crustal motion, particularly in seismically active regions; measurements of the Earth's rotation rate and pole orientation; high-precision Earth orbiter tracking; surveying; measurements of media propagation delays for calibration of deep space radiometric data in support of NASA planetary missions; determination of precise ground station coordinates; and precise time transfer worldwide.

Lichten, Stephen M.

1991-01-01

37

High precision fiber SINS with spin technology  

NASA Astrophysics Data System (ADS)

Fiber strapdown inertial navigation system (FSINS) is presently used in several applications related to marine navigation. However, the absolute position from FSINS contains the error that increases with time, which prevents its long-term use for the ship cruise. In order to improve the performance of FSINS based on our present inertial sensors, the spin technology was proposed in the system to mitigate the navigation errors and a prototype of the proposed system was developed in Navigation Lab. The prototype contains the IMU, temperature controller, rotating configuration, navigation and I/O electronics group, control and display, power supply subsystem and other modules. In the proposed spin technology, the IMU is rotated back and forth in azimuth through four orthogonal positions relative to the ship's longitudinal axis. Experimental testing was conducted for the prototype in the laboratory and the results showed that the RFSINS's navigation performance is improved 10 times.

Sun, Wei; Sun, Feng; Wang, Da-xue

2013-10-01

38

High-precision hydraulic Stewart platform  

Microsoft Academic Search

We present a novel design for a Stewart platform (or hexapod), an apparatus which performs positioning tasks with high accuracy. The platform, which is supported by six hydraulic telescopic struts, provides six degrees of freedom with 1 mum resolution. Rotations about user defined pivot points can be specified for any axis of rotation with microradian accuracy. Motion of the platform

Roelof G. van Silfhout

1999-01-01

39

High-precision hydraulic Stewart platform  

Microsoft Academic Search

We present a novel design for a Stewart platform (or hexapod), an apparatus which performs positioning tasks with high accuracy. The platform, which is supported by six hydraulic telescopic struts, provides six degrees of freedom with 1 ?m resolution. Rotations about user defined pivot points can be specified for any axis of rotation with microradian accuracy. Motion of the platform

Roelof G. van Silfhout

1999-01-01

40

High precision mass measurements for wine metabolomics  

PubMed Central

An overview of the critical steps for the non-targeted Ultra-High Performance Liquid Chromatography coupled with Quadrupole Time-of-Flight Mass Spectrometry (UPLC-Q-ToF-MS) analysis of wine chemistry is given, ranging from the study design, data preprocessing and statistical analyses, to markers identification. UPLC-Q-ToF-MS data was enhanced by the alignment of exact mass data from FTICR-MS, and marker peaks were identified using UPLC-Q-ToF-MS2. In combination with multivariate statistical tools and the annotation of peaks with metabolites from relevant databases, this analytical process provides a fine description of the chemical complexity of wines, as exemplified in the case of red (Pinot noir) and white (Chardonnay) wines from various geographic origins in Burgundy.

Roullier-Gall, Chloé; Witting, Michael; Gougeon, Régis D.; Schmitt-Kopplin, Philippe

2014-01-01

41

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

42

High-precision optical and microwave signal synthesis and distribution  

E-print Network

In this thesis, techniques for high-precision synthesis of optical and microwave signals and their distribution to remote locations are presented. The first topic is ultrafast optical pulse synthesis by coherent superposition ...

Kim, Jung-Won, 1976-

2007-01-01

43

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

44

High precision framework for chaos many-body engine  

NASA Astrophysics Data System (ADS)

In this paper we present a C# 4.0 high precision framework for simulation of relativistic many-body systems. In order to benefit from the, previously developed, chaos analysis instruments, all new modules were integrated with Chaos Many-Body Engine (Grossu et al. 2010, 2013). As a direct application, we used 46 digits precision for analyzing the "Butterfly Effect" of the gravitational force in a specific relativistic nuclear collision toy-model.

Grossu, I. V.; Besliu, C.; Felea, D.; Jipa, Al.

2014-04-01

45

A Comparison of three high-precision quadrature schemes  

SciTech Connect

The authors have implemented three numerical quadrature schemes, using the new Arbitrary Precision (ARPREC) software package, with the objective of seeking a completely ''automatic'' arbitrary precision quadrature facility, namely one that does not rely on a priori information of the function to be integrated. Such a facility is required, for example, to permit the experimental identification of definite integrals based on their numerical values. The performance and accuracy of these three quadrature schemes are compared using a suite of 15 integrals, ranging from continuous, well-behaved functions on finite intervals to functions with vertical derivatives and integrable singularities at endpoints, as well as several integrals on an infinite interval.

Bailey, David H.; Li, Xiaoye S.

2003-07-01

46

Experimental Dynamic Characterization of a Reconfigurable Adaptive Precision Truss  

NASA Technical Reports Server (NTRS)

The dynamic behavior of a reconfigurable adaptive truss structure with non-linear joints is investigated. The objective is to experimentally examine the effects of the local non-linearities on the global dynamics of the structure. Amplitude changes in the frequency response functions are measured at micron levels of motion. The amplitude and frequency variations of a number of modes indicate a non-linear Coulomb friction response. Hysteretic bifurcation behavior is also measured at an amplitude approximately equal to the specified free-play in the joint. Under the 1 g pre-load, however, the non-linearity was dominantly characteristic of Coulomb friction with little evidence of free-play stiffening.

Hinkle, J. D.; Peterson, L. D.

1994-01-01

47

Computer-controlled high-precision Michelson wavemeter  

NASA Astrophysics Data System (ADS)

The Michelson wavemeter is a popular instrument in many experiments where the high-precision measurement of a cw laser wavelength is required. In this paper, we describe a simple and inexpensive way to obtain high-precision measurements with this classical physicist's tool. We exploit the time stamp provided by the high-frequency clock present in modern data acquisition cards to measure the fractional uncertainty of the interference signal. The resulting relative uncertainty value for our current set-up is of the order of 10-8 and can be potentially improved by a factor of 100.

Pedregosa-Gutierrez, J.; Guyomarc'h, D.; Vedel, M.; Champenois, C.; Knoop, M.

2014-09-01

48

High precision patterning of ITO using femtosecond laser annealing process  

NASA Astrophysics Data System (ADS)

High precision patterning of crystalline indium tin oxide (c-ITO) patterns on amorphous ITO (a-ITO) thin films by femtosecond laser-induced crystallization with a Gaussian beam profile followed by chemical etching is demonstrated. In the proposed approach, the a-ITO thin film is selectively transformed into a c-ITO structure via a low heat affect zone and the well-defined thresholds (ablation and crystallization) supplied by the femtosecond laser pulse. The experimental results show that by careful control of the laser fluence above the crystallization threshold, c-ITO patterns with controllable line widths and ridge-free characteristics can be accomplished. By careful control of the laser fluence above the ablation threshold, fast fabrication of the two parallel sub-micro c-ITO line patterns using a single femtosecond laser beam and single scanning path can be achieved. Along-length sub-micro c-ITO line pattern is fabricated, and the feasibility of fabricating c-ITO patterns is confirmed, which are expected to be used in micro-electronics devices.

Cheng, Chung-Wei; Lin, Cen-Ying

2014-09-01

49

High Precision Pointing Stability and Control for Exoplanet Missions  

NASA Astrophysics Data System (ADS)

Exoplanet imaging and characterization space observatories require high precision pointing stability and stability. We have developed a toolbox of sensors, actuators and algorithms along with a systems approach to meet the demanding needs of these missions. Grown from developments and experience gained from high precision Earth remote sensing missions such as the WorldView satellites, as well as high performance astrophysics missions such as Kepler and JWST, these capabilities are enabling for a wide range of future missions. The approaches take advantage of highly flexible software architectures; Enhanced ground simulation capabilities for system tuning and verification and validation; Testing capabilities to verify our modelling; High precision sensors including sub-arc-second star trackers and fine guidance sensors; High bandwidth fast steering mirrors for optical path control; and high precision reaction wheels and control moment gyros for overall observatory control. Many of these capabilities coupled with innovative thinking have been applied to the recent Kepler mission to enable the K2 extended mission concept.

Barnes, Arnold; Troeltzsch, John; Wiemer, Doug

2014-06-01

50

Research on high-precision hole measurement based on robot vision method  

NASA Astrophysics Data System (ADS)

A high-precision vision detection and measurement system using mobile robot is established for the industry field detection of motorcycle frame hole and its diameter measurement. The robot path planning method is researched, and the non-contact measurement method with high precision based on visual digital image edge extraction and hole spatial circle fitting is presented. The Canny operator is used to extract the edge of captured image, the Lagrange interpolation algorithm is utilized to determine the missing image edge points and calculate the centroid, and the least squares fitting method is adopted to fit the image edge points. Experimental results show that the system can be used for the high-precision real-time measurement of hole on motorcycle frame. The absolute standard deviation of the proposed method is 0.026 7 mm. The proposed method can not only improve the measurement speed and precision, but also reduce the measurement error.

Song, Li-mei; Li, Da-peng; Qin, Ming-cui; Li, Zong-yan; Chang, Yu-lan; Xi, Jiang-tao

2014-09-01

51

High precision framework for Chaos Many-Body Engine  

E-print Network

In this paper we present a C# 4.0 high precision framework for simulation of relativistic many-body systems. In order to benefit from, previously developed, chaos analysis instruments, all new modules were designed to be integrated with Chaos Many-Body Engine [1,3]. As a direct application, we used 46 digits precision for analyzing the Butterfly Effect of the gravitational force in a specific relativistic nuclear collision toy-model. Trying to investigate the average Lyapunov Exponent dependency on the incident momentum, an interesting case of intermittency was noticed. Based on the same framework, other high-precision simulations are currently in progress (e.g. study on the possibility of considering, hard to detect, extremely low frequency photons as one of the dark matter components).

I. V. Grossu; C. Besliu; D. Felea; Al. Jipa

2013-03-04

52

High-precision readout circuit for LIGA acceleration sensors  

Microsoft Academic Search

For the past few years capacitive LIGA acceleration sensors have been fabricated at the Karlsruhe Nuclear Research Center. The advantages of LIGA acceleration sensors are their high zero-acceleration capacitance of 5 pF, temperature-compensated design with low offset temperature coefficient (TCO = 1.5 × 10?4 FSO K?1) and high linearity. In addition, a high-precision readout circuit has been developed. The electronic

O. Krömer; O. Fromhein; H. Gemmeke; T. Kühner; J. Mohr; M. Strohrmann

1995-01-01

53

Dipole model analysis of high precision HERA data  

E-print Network

We analyse, within a dipole model, the inclusive DIS cross section data, obtained from the combination of the H1 and ZEUS HERA measurements. We show that these high precision data are very well described within the dipole model framework, which is complemented with a valence quark structure functions. We discuss the properties of the gluon density obtained in this way.

Agnieszka Luszczak; Henri Kowalski

2013-12-14

54

High precision measurements of Na-26 beta(-) decay  

E-print Network

High-precision measurements of the half-life and beta-branching ratios for the beta(-) decay of Na-26 to Mg-26 have been measured in beta-counting and gamma-decay experiments, respectively. A 4 pi proportional counter and fast tape transport system...

Grinyer, GF; Svensson, CE; Andreoiu, C.; Andreyev, AN; Austin, RAE; Ball, GC; Chakrawarthy, RS; Finlay, P.; Garrett, PE; Hackman, G.; Hardy, John C.; Hyland, B.; Iacob, VE; Koopmans, KA; Kulp, WD; Leslie, JR; Macdonald, JA; Morton, AC; Ormand, WE; Osborne, CJ; Pearson, CJ; Phillips, AA; Sarazin, F.; Schumaker, MA; Scraggs, HC; Schwarzenberg, J.; Smith, MB; Valiente-Dobon, JJ; Waddington, JC; Wood, JL; Zganjar, EF.

2005-01-01

55

High precision phase measurement technique for cell impedance spectroscopy  

Microsoft Academic Search

This paper presents a new approach for high precision phase measurement. The new system is developed for biomedical applications such as complex cell impedance measurement and dielectric tissue analysis. In many of the named applications it is necessary to measure the complex dielectric constant of a sample as a function of frequency. Therefore the developed system is capable of measuring

Dennis Trebbels; Daniel Woelki; Roland Zengerle

2010-01-01

56

High precision module for Chaos Many-Body Engine  

E-print Network

In this paper we present a C# high precision relativistic many-body module integrated with Chaos Many-Body Engine. As a direct application, we used it for estimating the butterfly effect involved by the gravitational force in a specific nuclear relativistic collision toy-model.

Grossu, I V; Felea, D; Jipa, Al

2014-01-01

57

High Precision Mass Measurements in $\\psi$ and $\\Upsilon$ Families Revisited  

E-print Network

High precision mass measurements in $\\Psi$ and $\\Upsilon$ families performed in 1980-1984 at the VEPP-4 collider with OLYA and MD-1 detectors are revisited. The corrections for the new value of the electron mass are presented. The effect of the updated radiative corrections has been calculated for the $J/\\Psi(1S)$ and $\\Psi(2S)$ mass measurements.

Artamonov, S A; Blinov, A E; Blinov, V E; Bondar, A E; Bukin, A D; Chilingarov, A G; Denisov, N F; Eidelman, S I; Eidelman, Yu I; Groshev, V R; Inozemtsev, N I; Kezerashvili, G Ya; Kiselev, V A; Klimenko, S G; Kolachev, G M; Kuper, E A; Kurdadze, L M; Lelchuk, M Yu; Mishnev, S I; Nikitin, S A; Onuchin, A P; Pakhtusova, E V; Panin, V S; Petrov, V V; Protopopov, I Ya; Saldin, E L; Shamov, A G; Shatunov, Yu M; Shwartz, B A; Sidorov, V A; Skovpen, Yu I; Skrinsky, A N; Tayursky, V A; Telnov, V I; Temnykh, A B; Tikhonov, Yu A; Tumaikin, G M; Undrus, A E; Vorobiev, A I; Yurkov, M V; Zhilich, V N; Zholents, A A

2000-01-01

58

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

59

GENERATION AND CONTROL OF HIGH PRECISION BEAMS AT LEPTON ACCELERATORS  

SciTech Connect

Parity violation experiments require precision manipulation of helicity-correlated beam coordinates on target at the nm/nrad-level. Achieving this unprecedented level of control requires a detailed understanding of the particle optics and careful tuning of the beam transport to keep anomalies from compromising the design adiabatic damping. Such efforts are often hindered by machine configuration and instrumentation limitations at the low energy end. A technique has been developed at CEBAF including high precision measurements, Mathematica-based analysis for obtaining corrective solutions, and control hardware/software developments for realizing such level of control at energies up to 5 GeV.

Yu-Chiu Chao

2007-06-25

60

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

61

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

62

High-precision calculations of van der Waals coefficients for heteronuclear alkali-metal dimers  

NASA Astrophysics Data System (ADS)

van der Waals coefficients for the heteronuclear alkali-metal dimers of Li, Na, K, Rb, Cs, and Fr are calculated using relativistic ab initio methods augmented by high-precision experimental data. We argue that the uncertainties in the coefficients are unlikely to exceed about 1%.

Derevianko, A.; Babb, J. F.; Dalgarno, A.

2001-05-01

63

High-precision buffer circuit for suppression of regenerative oscillation  

NASA Technical Reports Server (NTRS)

Precision analog signal conditioning electronics have been developed for wind tunnel model attitude inertial sensors. This application requires low-noise, stable, microvolt-level DC performance and a high-precision buffered output. Capacitive loading of the operational amplifier output stages due to the wind tunnel analog signal distribution facilities caused regenerative oscillation and consequent rectification bias errors. Oscillation suppression techniques commonly used in audio applications were inadequate to maintain the performance requirements for the measurement of attitude for wind tunnel models. Feedback control theory is applied to develop a suppression technique based on a known compensation (snubber) circuit, which provides superior oscillation suppression with high output isolation and preserves the low-noise low-offset performance of the signal conditioning electronics. A practical design technique is developed to select the parameters for the compensation circuit to suppress regenerative oscillation occurring when typical shielded cable loads are driven.

Tripp, John S.; Hare, David A.; Tcheng, Ping

1995-01-01

64

Strategy for Realizing High-Precision VUV Spectro-Polarimeter  

NASA Astrophysics Data System (ADS)

Spectro-polarimetric observations in the vacuum ultraviolet (VUV) range are currently the only means to measure magnetic fields in the upper chromosphere and transition region of the solar atmosphere. The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) aims to measure linear polarization at the hydrogen Lyman- ? line (121.6 nm). This measurement requires a polarization sensitivity better than 0.1 %, which is unprecedented in the VUV range. We here present a strategy with which to realize such high-precision spectro-polarimetry. This involves the optimization of instrument design, testing of optical components, extensive analyses of polarization errors, polarization calibration of the instrument, and calibration with onboard data. We expect that this strategy will aid the development of other advanced high-precision polarimeters in the UV as well as in other wavelength ranges.

Ishikawa, R.; Narukage, N.; Kubo, M.; Ishikawa, S.; Kano, R.; Tsuneta, S.

2014-12-01

65

Flight test performance of a high precision navigation Doppler lidar  

NASA Astrophysics Data System (ADS)

A navigation Doppler Lidar (DL) was developed at NASA Langley Research Center (LaRC) for high precision velocity measurements from a lunar or planetary landing vehicle in support of the Autonomous Landing and Hazard Avoidance Technology (ALHAT) project. A unique feature of this DL is that it has the capability to provide a precision velocity vector which can be easily separated into horizontal and vertical velocity components and high accuracy line of sight (LOS) range measurements. This dual mode of operation can provide useful information, such as vehicle orientation relative to the direction of travel, and vehicle attitude relative to the sensor footprint on the ground. System performance was evaluated in a series of helicopter flight tests over the California desert. This paper provides a description of the DL system and presents results obtained from these flight tests.

Pierrottet, Diego; Amzajerdian, Farzin; Petway, Larry; Barnes, Bruce; Lockard, George

2009-05-01

66

High-precision temperature control system based on PID algorithm  

Microsoft Academic Search

This system uses 8bit AT89C51 CPU as a core for building a electronic oven temperature control system with high precision, the temperature was changed to voltage signals by the thermal resistor PT1000 and amplified by LM358, then the analog voltage signal is converted to digital data by the AD0809. The PID algorithm was adopted as the software for power and

Jun-hong Yang; Xi-yan Bi

2010-01-01

67

High precision damage-resistant multiple-pass ultraviolet reflectometer  

SciTech Connect

A multiple-pass cell was reported by John White in 1942. Since them, it has been adapted for use as a high-precision reflectometer. The multiple-pass reflectometer has been studied and reported by Arnon and Baumeister. Here, a reflectometer which is similar is described. It utilizes a uv laser operating at lambda = 351 nm as the source and the White-cell mirrors are high-reflection dielectric coatings designed for that wavelength. Because of the low-loss reflectors used in the cell, a high number of traversals, reflections, can be achieved; R greater than or equal to 239. The use of dielectric mirrors also improves the damage resistance of the apparatus which is important when a uv laser beam is used. The results of reflectance measurements performed on several ultraviolet high reflectors are also reported. These include conventional dielectric coatings as well as a hybrid coating consisting of Al/sub 2/O/sub 3/, HfO/sub 2/, and SiO/sub 2/ layers. The Los Alamos optical damage laboratory has observed and defined several types of laser-induced damage to optical materials. In the case of high reflection, multi-layer, dielectric coatings, damage may be defined as any change in the coating layers or at the substrate interface which causes a measurable change in reflectance at its design wavelength. Since most dielectric high reflectors have reflectances approaching unity, and a change caused by laser irradiation can be minute, a precise method for measuring high reflectance must be utilized. A multiple-pass reflectometer based on the White cell was selected because of its demonstratd precision and high accuracy. It utilizes a laser as the source for reasons described later.

Jolin, L.J.; Foltyn, S.R.

1984-01-01

68

Precision-biased Parsing and High-Quality Parse Selection  

E-print Network

We introduce precision-biased parsing: a parsing task which favors precision over recall by allowing the parser to abstain from decisions deemed uncertain. We focus on dependency-parsing and present an ensemble method which is capable of assigning parents to 84% of the text tokens while being over 96% accurate on these tokens. We use the precision-biased parsing task to solve the related high-quality parse-selection task: finding a subset of high-quality (accurate) trees in a large collection of parsed text. We present a method for choosing over a third of the input trees while keeping unlabeled dependency parsing accuracy of 97% on these trees. We also present a method which is not based on an ensemble but rather on directly predicting the risk associated with individual parser decisions. In addition to its efficiency, this method demonstrates that a parsing system can provide reasonable estimates of confidence in its predictions without relying on ensembles or aggregate corpus counts.

Goldberg, Yoav

2012-01-01

69

High-resolution accelerator-based mass spectrometry: precision, accuracy and background.  

PubMed

Radiocarbon accelerator mass spectrometry (AMS) is a high-sensitivity analysis technique which is nowadays widely used in many research fields such as archaeology, geology, environmental and earth sciences. We report on the features of the new high throughput accelerator mass spectrometer at the University of Lecce, Italy. The experimental apparatus is described and its general characteristics are reported in terms of measurement precision, accuracy and achievable background. PMID:15701419

Calcagnile, L; Quarta, G; D'Elia, M

2005-04-01

70

High Precision Oxygen Measurements as a Tool for CCS Monitoring  

NASA Astrophysics Data System (ADS)

CO2 emissions from below ground carbon storage reservoirs can be difficult to discriminate from CO2 produced via natural plant and microbial respiration. However, because respiration produces CO2 and consumes O2 in an approximately 1:1 ratio, it is possible to characterize leakage sources by measurement of simultaneous changes of both O2 and CO2. This approach is complicated by the fact that O2 comprises approximately 21% of the atmosphere, while CO2 is only present in the background atmosphere at ~400 parts per million, making it necessary to accurately measure changes in O2 concentration to six significant figures. Here we describe a portable high precision oxygen measurement system that employs a modified commercial fuel cell analyzer to quantify small changes in O2 concentration. High precision is achieved through precise control of flow and pressure, allowing near part per million precision of O2 and CO2 concentrations. This system has been incorporated into a mobile laboratory and has been deployed to the ZERT controlled release site in Bozeman, Montana and to a natural analog CO2 leak at Soda Springs, Idaho. Samples were collected at ground level, 1 meter, and 3 meters above the CO2 source and are displayed as the ratio of the O2 difference relative to a reference to the CO2 difference in concentration relative to the same reference (?O2/?CO2). It was observed that at wind speeds ? 2 m/s, the ?O2/?CO2 anomaly decreased with height and was still significantly different from background at 3 m. With increasing wind speed, ?O2/?CO2 anomalies decreased to background levels at 1 and 3 m but remained detectable at the ground surface. We will discuss attempts to quantify the CO2 release rate utilizing the measured ?O2/?CO2 elevation profiles and will present complementary eddy covariance data for comparison.

Trugman, A. T.; Dvonch, C.; Clegg, S. M.; Rahn, T.

2011-12-01

71

High-precision measurement of the half-life of $^{62}$Ga  

E-print Network

The beta-decay half-life of 62Ga has been studied with high precision using on-line mass separated samples. The decay of 62Ga which is dominated by a 0+ to 0+ transition to the ground state of 62Zn yields a half-life of T_{1/2} = 116.19(4) ms. This result is more precise than any previous measurement by about a factor of four or more. The present value is in agreement with older literature values, but slightly disagrees with a recent measurement. We determine an error weighted average value of all experimental half-lives of 116.18(4) ms.

B. Blank; G. Savard; J. Doring; A. Blazhev; G. Canchel; M. Chartier; D. Henderson; Z. Janas; R. Kirchner; I. Mukha; E. Roeckl; K. Schmidt; J. Zylicz

2003-10-29

72

Ultra-high precision cosmology from gravitational waves  

E-print Network

We show that the Big Bang Observer (BBO), a proposed space-based gravitational-wave (GW) detector, would provide ultra-precise measurements of cosmological parameters. By detecting ~300,000 compact-star binaries, and utilizing them as standard sirens, BBO would determine the Hubble constant to 0.1%, and the dark energy parameters w_0 and w_a to ~0.01 and 0.1,resp. BBO's dark-energy figure-of-merit would be approximately an order of magnitude better than all other proposed dark energy missions. To date, BBO has been designed with the primary goal of searching for gravitational waves from inflation. To observe this inflationary background, BBO would first have to detect and subtract out ~300,000 merging compact-star binaries, out to z~5. It is precisely this foreground which would enable high-precision cosmology. BBO would determine the luminosity distance to each binary to ~percent accuracy. BBO's angular resolution would be sufficient to uniquely identify the host galaxy for most binaries; a coordinated optical/infrared observing campaign could obtain the redshifts. Combining the GW-derived distances and EM-derived redshifts for such a large sample of objects leads to extraordinarily tight constraints on cosmological parameters. Such ``standard siren'' measurements of cosmology avoid many of the systematic errors associated with other techniques. We also show that BBO would be an exceptionally powerful gravitational lensing mission, and we briefly discuss other astronomical uses of BBO.

Curt Cutler; Daniel E. Holz

2009-06-19

73

Ultra-high precision cosmology from gravitational waves  

E-print Network

We show that the Big Bang Observer (BBO), a proposed space-based gravitational-wave (GW) detector, would provide ultra-precise measurements of cosmological parameters. By detecting ~300,000 compact-star binaries, and utilizing them as standard sirens, BBO would determine the Hubble constant to 0.1%, and the dark energy parameters w_0 and w_a to ~0.01 and 0.1,resp. BBO's dark-energy figure-of-merit would be approximately an order of magnitude better than all other proposed dark energy missions. To date, BBO has been designed with the primary goal of searching for gravitational waves from inflation. To observe this inflationary background, BBO would first have to detect and subtract out ~300,000 merging compact-star binaries, out to z~5. It is precisely this foreground which would enable high-precision cosmology. BBO would determine the luminosity distance to each binary to ~percent accuracy. BBO's angular resolution would be sufficient to uniquely identify the host galaxy for most binaries; a coordinated optic...

Cutler, Curt

2009-01-01

74

High-Precision Floating-Point Arithmetic in ScientificComputation  

SciTech Connect

At the present time, IEEE 64-bit floating-point arithmetic is sufficiently accurate for most scientific applications. However, for a rapidly growing body of important scientific computing applications, a higher level of numeric precision is required: some of these applications require roughly twice this level; others require four times; while still others require hundreds or more digits to obtain numerically meaningful results. Such calculations have been facilitated by new high-precision software packages that include high-level language translation modules to minimize the conversion effort. These activities have yielded a number of interesting new scientific results in fields as diverse as quantum theory, climate modeling and experimental mathematics, a few of which are described in this article. Such developments suggest that in the future, the numeric precision used for a scientific computation may be as important to the program design as are the algorithms and data structures.

Bailey, David H.

2004-12-31

75

Finite element simulation in fabrication of high-precision reflector panels  

NASA Astrophysics Data System (ADS)

Millimeter and sub-millimeter wave observations, however, which largely depend on the instrumentation techniques, provide vital experimental verifications for the theoretical studies of stars formation. To obtain the stronger and more precise radio spectrum signals, high precision reflector panels that are demanded in great amount especially for the large-aperture antenna and antenna-array. Many years, experts have put emphasis on the precise forming of reflector panels. This paper presents the high-precision panels with a sandwich-type construction of one skin-plate and one aluminum backup structural combined with structural adhesive, with high precision modules as the fundamental condition. The skin-plate fit the module well due to its flexible. The structural adhesive, with good flow-ability, automatically compensate the deviations between the skin-plate and the backup structural. In the end, individually shaped sandwich-like panels assemble up the high surface-accuracy reflectors. The internal stress analysis of skin-plate and structural adhesive are of utmost importance. Therefore, several kinds of skin-plate and structural adhesive in different material properties are listed and simulated with finite element method (ANSYS). Based on the simulation results, processing parameters to panel fabrication are determined more efficient and accurate.

Yan, Lei; Chen, Yi

2012-09-01

76

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

77

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

78

High Precision Astrometry in Asteroid Mitigation - the NEOShield Perspective  

NASA Astrophysics Data System (ADS)

Among the currently known Near Earth Objects (NEOs), roughly 1400 are classified as being potentially hazardous asteroids. The recent Chelyabinsk event has shown that these objects can pose a real threat to mankind. We illustrate that high precision asteroid astrometry plays a vital role in determining potential impact risks, selecting targets for deflection demonstration missions and evaluating mitigation mission success. After a brief introduction to the NEO-Shield project, an international effort initiated by the European Commission to investigate aspects of NEO mitigation in a comprehensive fashion, we discuss current astrometric performances, requirements and possible issues with NEO risk assessment and deflection demonstration missions.

Eggl, S.; Ivantsov, A.; Hestroffer, D.; Perna, D.; Bancelin, D.; Thuillot, W.

2013-11-01

79

DIPOL-2: a double image high precision polarimeter  

NASA Astrophysics Data System (ADS)

We have built a new broad-band polarimeter (DIPOL-2), capable of measuring polarization with the precision at the 10-5 level. Two dichroic beam-splitters are used to split light into three passbands (BVR), simultaneously recorded with three CCDs. A rotatable superachromatic ?/2 (or ?/4) plate is used as the polarization modulator and a plane parallel calcite plate as the polarization analyzer. Simple yet effective design with small number of optical elements and moving mechanical parts makes DIPOL-2 a highly versatile and reliable instrument with negligible instrumental polarization, very well suitable for observations with remotely controlled telescopes. Current and planned observing programs are briefly described.

Piirola, V.; Berdyugin, A.; Berdyugina, Svetlana

2014-08-01

80

Development of high-precision laser heterodyne metrology gauges  

NASA Astrophysics Data System (ADS)

Laser interferometers with better than10 picometer (pm) accuracy in displacement measurement and 1-3 microns in absolute distance ranging accuracy are sought in several of NASA's planned missions, such as the Space Interferometry Mission (SIM) and Terrestrial Planet Finder (TPF). Over the past several years, we have made significant progress at JPL toward a laser heterodyne interferometer system that can provide both picometer displacement measurement and micron level absolute distance measurement. This paper presents an review on the development of high precision metrology gauges for these missions.

Zhao, Feng

2005-02-01

81

High-precision measurements of global stellar magnetic fields  

NASA Astrophysics Data System (ADS)

This paper presents a brief history of the development of devices and techniques for high-precision measurements of stellar magnetic fields. Two main approaches for the processing of spectral-polarimetric observations are described: the method of least-squares deconvolution (LSD), which is used to find a mean-weighted average of the normalized polarization profile using a set of spectral lines, and a method in which each individual spectral line is used to determine the magnetic field, viz., the single line method (SL). The advantages and disadvantages of the LSD and SL methods are discussed.

Plachinda, S. I.

2014-06-01

82

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. PMID:23529116

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

2013-01-01

83

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

2013-01-01

84

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

85

High-precision silicon nitride balls for bearings  

NASA Astrophysics Data System (ADS)

Hybrid ceramic bearings are now commercially available for use in high performance applications where the properties of the ceramic balls give advantages in terms of higher operating speeds, increased stiffness, lower fraction and less heat generation. Most hybrid bearings are high precision angular contact ball bearings fitted with silicon nitride balls, which have to be finished to ISO dimensional grades 3 and 5. Ball diameter variation and deviation from the spherical form has to be less than 0.125 micrometers for Grade 5 balls and less than 0.08 micrometers for Grade 3 balls. Surface finish of silicon nitride balls is typically 0.003 - 0.010 micrometers Rq (0.002 - 0.008 micrometers Ra). At this level, the basic material microstructures is discernible which facilitates inspection for material and other faults.

Cundill, Robin T.

1992-04-01

86

Electronics design for a high precision image stabilization system  

NASA Astrophysics Data System (ADS)

A very high precision Image Stabilization System has been designed for the Solar Orbiter mission. The different components that have been designed are the Correlation Tracking Camera (CTC), Tip-Tilt controller (TTC) and the system control in order to achieve the specified requirements. For the CTC, in order to achieve the required resolution of 12 bits and reduced power consumption, we used an external ADC. For the TTC, a special focus has been dedicated to a 55 V linear regulator in a QUASI-LDO configuration and a Tip-Tilt driver in a transconductance amplifier architecture. Results show that the full system reaches an attenuation of 1/10th of a pixel at 10Hz. The TTC provides a high voltage span, enough slew-rate and the needed stability levels.

Casas, A.; Roma, D.; Carmona, M.; Gómez, J. M.; Bosch, J.; López, M.; Sabater, J.; Herms, A.; Maue, T.; Nakai, E.; Volkmer, R.; Schmidt, W.

2014-07-01

87

Observing exoplanet populations with high-precision astrometry  

NASA Astrophysics Data System (ADS)

This thesis deals with the application of the astrometry technique, consisting in measuring the position of a star in the plane of the sky, for the discovery and characterisation of extra-solar planets. It is feasible only with a very high measurement precision, which motivates the use of space observatories, the development of new ground-based astronomical instrumentation and of innovative data analysis methods: The study of Sun-like stars with substellar companions using CORALIE radial velocities and HIPPARCOS astrometry leads to the determination of the frequency of close brown dwarf companions and to the discovery of a dividing line between massive planets and brown dwarf companions; An observation campaign employing optical imaging with a very large telescope demonstrates sufficient astrometric precision to detect planets around ultra-cool dwarf stars and the first results of the survey are presented; Finally, the design and initial astrometric performance of PRIMA, ! a new dual-feed near-infrared interferometric observing facility for relative astrometry is presented.

Sahlmann, Johannes

2012-06-01

88

A simple high-precision Jacob's staff design for the high-resolution stratigrapher  

USGS Publications Warehouse

The new generation of high-resolution stratigraphic research depends upon detailed bed-by-bed analysis to enhance regional correlation potential. The standard Jacob's staff is not an efficient and precise tool for measuring thin-bedded strata. The high-precision Jacob's staff design presented and illustrated in this paper meets the qualifications required of such an instrument. The prototype of this simple design consists of a sliding bracket that holds a Brunton-type compass at right angles to a ruled-off staff. This instrument provides rapid and accurate measurement of both thick- or thin-bedded sequences, thus decreasing field time and increasing stratigraphic precision. -Author

Elder, W.P.

1989-01-01

89

Highly precise and robust packaging of optical components  

NASA Astrophysics Data System (ADS)

In this paper we present the development of a compact, thermo-optically stable and vibration and mechanical shock resistant mounting technique by soldering of optical components. Based on this technique a new generation of laser sources for aerospace applications is designed. In these laser systems solder technique replaces the glued and bolted connections between optical component, mount and base plate. Alignment precision in the arc second range and realization of long term stability of every single part in the laser system is the main challenge. At the Fraunhofer Institute for Laser Technology ILT a soldering and mounting technique has been developed for high precision packaging. The specified environmental boundary conditions (e.g. a temperature range of -40 °C to +50 °C) and the required degrees of freedom for the alignment of the components have been taken into account for this technique. In general the advantage of soldering compared to gluing is that there is no outgassing. In addition no flux is needed in our special process. The joining process allows multiple alignments by remelting the solder. The alignment is done in the liquid phase of the solder by a 6 axis manipulator with a step width in the nm range and a tilt in the arc second range. In a next step the optical components have to pass the environmental tests. The total misalignment of the component to its adapter after the thermal cycle tests is less than 10 arc seconds. The mechanical stability tests regarding shear, vibration and shock behavior are well within the requirements.

Leers, Michael; Winzen, Matthias; Liermann, Erik; Faidel, Heinrich; Westphalen, Thomas; Miesner, Jörn; Luttmann, Jörg; Hoffmann, Dieter

2012-03-01

90

Design and development of a high-precision, high-payload telescope dual-drive system  

Microsoft Academic Search

A high precision, dual drive system has been designed and developed for the Wide Field Upgrade to the Hobby-Eberly Telescope* at McDonald Observatory in support of the Hobby-Eberly Telescope Dark Energy Experiment?. Analysis, design and controls details will be of interest to designers of large scale, high precision robotic motion devices. The drive system positions the 19,000 kg star tracker

Michael S. Worthington; Timothy A. Beets; Joseph H. Beno; Jason R. Mock; Brian T. Murphy; Brian J. South; John M. Good

2010-01-01

91

Silicon Avalanche Pixel Sensor for High Precision Tracking  

E-print Network

The development of an innovative position sensitive pixelated sensor to detect and measure with high precision the coordinates of the ionizing particles is proposed. The silicon avalanche pixel sensors (APiX) is based on the vertical integration of avalanche pixels connected in pairs and operated in coincidence in fully digital mode and with the processing electronics embedded on the chip. The APiX sensor addresses the need to minimize the material budget and related multiple scattering effects in tracking systems requiring a high spatial resolution in the presence of a large occupancy. The expected operation of the new sensor features: low noise, low power consumption and suitable radiation tolerance. The APiX device provides on-chip digital information on the position of the coordinate of the impinging charged particle and can be seen as the building block of a modular system of pixelated arrays, implementing a sparsified readout. The technological challenges are the 3D integration of the device under CMOS processes and integration of processing electronics.

N. D'Ascenzo; P. S. Marrocchesi; C. S. Moon; F. Morsani; L. Ratti; V. Saveliev; A. Savoy Navarro; Q. Xie

2013-11-30

92

Silicon avalanche pixel sensor for high precision tracking  

NASA Astrophysics Data System (ADS)

The development of an innovative position sensitive pixelated sensor to detect and measure with high precision the coordinates of the ionizing particles is proposed. The silicon avalanche pixel sensors (APiX) is based on the vertical integration of avalanche pixels connected in pairs and operated in coincidence in fully digital mode and with the processing electronics embedded on the chip. The APiX sensor addresses the need to minimize the material budget and related multiple scattering effects in tracking systems requiring a high spatial resolution in the presence of the large track occupancy. The expected operation of the new sensor features: low noise, low power consumption and suitable radiation tolerance. The APiX device provides on-chip digital information on the position of the coordinate of the impinging charged particle and can be seen as the building block of a modular system of pixelated arrays, implementing a sparsified readout. The technological challenges are the 3D integration of the device under CMOS processes and integration of processing electronics.

D'Ascenzo, N.; Marrocchesi, P. S.; Moon, C. S.; Morsani, F.; Ratti, L.; Saveliev, V.; Savoy Navarro, A.; Xie, Q.

2014-03-01

93

High precision optical finishing of lightweight silicon carbide aspheric mirror  

NASA Astrophysics Data System (ADS)

Critical to the deployment of large surveillance optics into the space environment is the generation of high quality optics. Traditionally, aluminum, glass and beryllium have been used; however, silicon carbide becomes of increasing interest and availability due to its high strength. With the hardness of silicon carbide being similar to diamond, traditional polishing methods suffer from slow material removal rates, difficulty in achieving the desired figure and inherent risk of causing catastrophic damage to the lightweight structure. Rather than increasing structural capacity and mass of the substrate, our proprietary sub-aperture aspheric surface forming technology offers higher material removal rates (comparable to that of Zerodur or Fused Silica), a deterministic approach to achieving the desired figure while minimizing contact area and the resulting load on the optical structure. The technology performed on computer-controlled machines with motion control software providing precise and quick convergence of surface figure, as demonstrated by optically finishing lightweight silicon carbide aspheres. At the same time, it also offers the advantage of ideal pitch finish of low surface micro-roughness and low mid-spatial frequency error. This method provides a solution applicable to all common silicon carbide substrate materials, including substrates with CVD silicon carbide cladding, offered by major silicon carbide material suppliers. This paper discusses a demonstration mirror we polished using this novel technology. The mirror is a lightweight silicon carbide substrate with CVD silicon carbide cladding. It is a convex hyperbolic secondary mirror with 104mm diameter and approximately 20 microns aspheric departure from best-fit sphere. The mirror has been finished with surface irregularity of better than 1/50 wave RMS @632.8 nm and surface micro-roughness of under 2 angstroms RMS. The technology has the potential to be scaled up for manufacturing capabilities of large silicon carbide optics due to its high material removal rate.

Kong, John; Young, Kevin

2010-10-01

94

[High-precision wavelength calibration of wide-band monochromator].  

PubMed

Usually the monochromator is used to output monochromatic light to calibrate the space remote sensing spectrometer. In the present paper, the confidence of space remote sensing spectrometer is used as a standard to evaluate the precision of wide-band monochromator wavelength calibration. Through analysis of the accuracy of the instrument, the monochromator wavelength repeatability error and deviations was obtained respectively. And the intrinsic spectrum of the high pressure mercury lamp and the grating diffraction was used as calibration lines to avoid the error caused by replacing the light source. Through the special method of wavelength calibration to shorten the scan time, the Gaussian fitting was used to look for peaks of wavelength to reduce error. Finally, the relationship derived from polynomial fitting to measure the exact wavelengths' accuracy of the monochromator and calculate the calibration confidence of the space remote sensing spectrometer. Using this method, we can make wavelength accuracy of the 1.5 M monochromator with wavelength band from 200 to 840 nm to reach to +/- 0.016 nm, then the confidence of the space remote sensing spectrometer can reach to 99.82%. PMID:23285905

Zhang, Zi-Hui; Wang, Shu-Rong; Huang, Yu; Li, Bo; Yu, Xiang-Yang; Lin, Guan-Yu

2012-10-01

95

High precision relocation of earthquakes at Iliamna Volcano, Alaska  

USGS Publications Warehouse

In August 1996, a period of elevated seismicity commenced beneath Iliamna Volcano, Alaska. This activity lasted until early 1997, consisted of over 3000 earthquakes, and was accompanied by elevated emissions of volcanic gases. No eruption occurred and seismicity returned to background levels where it has remained since. We use waveform alignment with bispectrum-verified cross-correlation and double-difference methods to relocate over 2000 earthquakes from 1996 to 2005 with high precision (~ 100??m). The results of this analysis greatly clarify the distribution of seismic activity, revealing distinct features previously hidden by location scatter. A set of linear earthquake clusters diverges upward and southward from the main group of earthquakes. The events in these linear clusters show a clear southward migration with time. We suggest that these earthquakes represent either a response to degassing of the magma body, circulation of fluids due to exsolution from magma or heating of ground water, or possibly the intrusion of new dikes beneath Iliamna's southern flank. In addition, we speculate that the deeper, somewhat diffuse cluster of seismicity near and south of Iliamna's summit indicates the presence of an underlying magma body between about 2 and 4??km depth below sea level, based on similar features found previously at several other Alaskan volcanoes. ?? 2009 Elsevier B.V.

Statz-Boyer, P.; Thurber, C.; Pesicek, J.; Prejean, S.

2009-01-01

96

High Precision 40K/39K Ratio Determination  

NASA Astrophysics Data System (ADS)

Potassium is one of the eight most abundant chemical elements in the Earth's crust and a major element in many rock-forming minerals. The isotope 40K is radioactive and undergoes ?- decay to 40Ca (ca. 89.3%) and electron capture to 40Ar (ca. 10.7%). Both decays can potentially be used as dating systems. The most commonly used branch is the decay of 40K to 40Ar because it can yield highly precise ages. Both decay schemes rely on the knowledge of the 40K branching ratio and the natural 40K abundance. A 40K abundance of 0.011672±41 % was measured on terrestrial material [1]. The relative uncertainty of 0.35 % has not been improved since. Recent improvements in the precision of mass spectrometric measurements have led to the situation that the uncertainties on the K decay constant and the abundance of 40K are a major source of uncertainty on the measured ages. A more precise definition of the 40K decay constant was attempted by different research groups within the last decade [2-9] but the goal of obtaining 0.1 % relative uncertainty on K-Ar ages for geological materials, as requested by the EARTHtime initiative, has not been achieved yet. In order to improve on this situation we studied the abundances of the K isotopes in terrestrial standards. A ThermoFischer Triton+ thermal ionisation mass spectrometer was used for K isotope ratio measurements of the NIST SRM 918b K standard loaded on Ta filaments with 0.1M phosphoric acid. Three techniques were applied: (A) dynamic measurement with in-run normalisation to the IUPAC value 41K/39K=0.072168; (B) a simple total evaporation procedure; (C) the "NBL-modified" total evaporation [10]. The 40K ion beam was measured in a Faraday cup with a 1E12 ? resistor; 39K and 41K were collected in Faraday cups with 1E11 ? resistors. Amplifier gains were intercalibrated by supplying fixed voltages off-line. Different measurement techniques were combined with different loading procedures. We also tested ionisation yields for the evaporation procedures (B) and (C). Our measured 40K/39K ratios are statistically indistinguishable from those reported by [1] but have lower uncertainties. Techniques A, B and C gave 1 standard error of 0.07 %, 0.2 %, and 0.14 %, respectively. 1. Garner E.L. et al. (1975) J.Res.Natl.Bur.Stand.79A, 713-725. 2. Grau Malonda A., Grau Carles A. (2002) Appl. Radiat. Isot. 56, 153-156. 3. Kossert K., Günter E. (2004) Appl.Radiat.Isot.60, 459-464. 4. Krumrei T.V. et al. (2006) Chem.Geol. 227, 258-273. 5. Kwon J. et al. (2002) Math.Geol. 34, 457-475. 6. Min K. et al. (2000) Geochim. Cosmochim. Acta 64, 73-98. 7. Nägler T.F., Villa I.M. (2000) Chem. Geol. 169, 5-16. 8. Renne P.R. et al. (2010) Geochim. Cosmochim. Acta 74, 5349-5367. 9. Schwarz W.H. et al. (2011) Geochim. Cosmochim. Acta 75, 5094-5096. 10. Richter S., Goldberg S.A. (2003) Int. J. Mass Spect. 229, 181-197.

Naumenko, M. O.; Mezger, K.; Nagler, T. F.; Villa, I. M.

2012-12-01

97

High-precision timeline for Earth's most severe extinction  

E-print Network

The end-Permian mass extinction was the most severe loss of marine and terrestrial biota in the last 542 My. Understanding its cause and the controls on extinction/recovery dynamics depends on an accurate and precise age ...

Burgess, Seth D.

98

A precision detector for high-energy neutral pions  

Microsoft Academic Search

Summary  A system of eight lead-glass ?erenkov counters, each coupled to a veto scintillation counter, was used at Frascati in a measurement\\u000a of the Primakoff effect in the ?0 photoproduction on complex nuclei (1). The system as a whole is a precision ?0 detector: pion angle and energy are measured with a precision near to the limit attainable with present-day techniques.

G. Bellettini; C. Bemporad; P. L. Braccini; P. Benvenuti; L. Foà

1966-01-01

99

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

100

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

101

Precision Density Measurements Near the Helium Lambda Transition Using High-Q Microwave Cavities  

NASA Astrophysics Data System (ADS)

A new experimental approach for high-precision density measurements of liquid helium near the lambda transition is proposed. Using a high-Q Nb microwave cavity (Q ~ 10^10) and the high-resolution thermometry (HRT), the changes in the density of helium that fills the cavity can be detected to high precision by accurate measurements of the resonant frequency shift (? f) as a function of the temperature. Since the frequency shift provides direct information for the changes in the dielectric constant, and since the dielectric constant is related to the density through the Clausius-Mossotti relation, the capability of high resolution frequency measurements (to one part in 10^13) will enable us to resolve density changes to one part in 10^10. Numerical calculations have been performed to demonstrate the feasibility of this approach for mapping out the density profile of liquid helium which couples to the TE modes of a microwave cavity. For temperatures very near the lambda transition, a superfluid-normal fluid interface develops inside the cavity. A numerical algorithm is established to resolve the helium density profile in the cavity. Preliminary experimental data using a TM010 Nb cavity and with microkelvin temperature resolutions will be presented. *Supported by NASA contract and Packard Foundation.

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

1996-03-01

102

Ramsey method of separated oscillatory fields for high-precision penning trap mass spectrometry.  

PubMed

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 38Ca nuclide with an uncertainty of 1.1 x 10(-8) using the Penning trap mass spectrometer ISOLTRAP at CERN. The mass of the superallowed beta emitter 38Ca 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. PMID:17501414

George, S; Baruah, S; Blank, B; Blaum, K; Breitenfeldt, M; Hager, U; Herfurth, F; Herlert, A; Kellerbauer, A; Kluge, H-J; Kretzschmar, M; Lunney, D; Savreux, R; Schwarz, S; Schweikhard, L; Yazidjian, C

2007-04-20

103

Radio emission from Supernovae and High Precision Astrometry  

NASA Astrophysics Data System (ADS)

The present thesis work makes contributions in two scientific fronts: differential astrometry over the largest angular scales ever attempted (approx. 15 arcdegrees) and numerical simulations of radio emission from very young supernovae. In the first part, we describe the results of the use of very-long-baseline interferometry (VLBI) in one experiment designed to measure with very high precision the angular distance between the radio sources 1150+812 (QSO) and 1803+784 (BL Lac). We observed the radio sources on 19 November 1993 using an intercontinental array of radio telescopes, which simultaneously recorded at 2.3 and 8.4 GHz. VLBI differential astrometry is capable, Nature allowing, of yielding source positions with precisions well below the milliarcsecond level. To achieve this precision, we first had to accurately model the rotation of the interferometric fringes via the most precise models of Earth Orientation Parameters (EOP; precession, polar motion and UT1, nutation). With this model, we successfully connected our phase delay data at both frequencies and, using difference astrometric techniques, determined the coordinates of 1803+784 relative to those of 1150+812-within the IERS reference frame--with an standard error of about 0.6 mas in each coordinate. We then corrected for several effects including propagation medium (mainly the atmosphere and ionosphere), and opacity and source-structure effects within the radio sources. We stress that our dual-frequency measurements allowed us to accurately subtract the ionosphere contribution from our data. We also used GPS-based TEC measurements to independently find the ionosphere contribution, and showed that these contributions agree with our dual-frequency measurements within about 2 standard deviations in the less favorables cases (the longest baselines), but are usually well within one standard deviation. Our estimates of the relative positions, whether using dual-frequency-based or GPS-based ionosphere corrections, agree well within one standard deviation. In summary, our astrometric results demonstrate the feasibility of using phase-delay difference techniques (single-frequency or dual-frequency) for sources separated by as far as 15(deg) on the sky. This opens the avenue for the extension of the technique on a global scale with the aim of building up a quasi-inertial reference frame (of submilliarcsecond accuracy) based on extragalactic radio sources. The second part of this thesis is devoted to the study of the radio emission of the Type II supernova SN 1993J, whose relative proximity (it exploded in the Galaxy M81, at a distance of 10 million of light-years) has allowed us to observe it with VLBI at different radio frequency bands since June 1993. This radio supernova is the best studied one so far and thus a perfect laboratory to test supernova radio emission models. Early VLBI observations of this supernova by our group allowed us to discover the shell structure of SN 1993J--likely common to all supernovae--the youngest ever discovered in a supernova. Subsequently, our VLBI observations showed SN 1993J to be self-similarly expanding and, more recently, we used our VLBI observations at 3.6 and 6 cm in the period 6 through 42 months after explosion to show that the supernova expansion is decelerating, its size following a power-law with time (R t^m; m=0.86 +- 0.02). Our measurement of the expansion index yields estimates of the density of both supernova ejecta and circumstellar material in standard supernova explosion models. In particular, the density of the circumstellar material seems to be following a power-law less steep than usual (rhocs r^{-s}, with s approx. 1.66 instead of the standard s=2). Our VLBI observations also showed that the supernova radio emission comes from a shell of width 30% of the outer radius. In this thesis, we describe a numerical code that simulates synchrotron radio emission from a supernova. We assume that the supernova is self-similarly and spherically symmetric expanding, and that the radio emission comes only from its shell. We

Perez-Torres, M. A.

1999-11-01

104

Vibratory response of a precision double-multi-layer monochromator positioning system using a generic modeling program with experimental verification.  

SciTech Connect

A generic vibratory response-modeling program has been developed as a tool for designing high-precision optical positioning systems. The systems are modeled as rigid-body structures connected by linear non-rigid elements such as complex actuators and bearings. The full dynamic properties of each non-rigid element are determined experimentally or theoretically, then integrated into the program as inertial and stiffness matrices. Thus, it is possible to have a suite of standardize structural elements for modeling many different positioning systems that use standardized components. This paper will present the application of this program to a double-multi-layer monochromator positioning system that utilizes standardized components. Calculated results are compared to experimental modal analysis results.

Barraza, J.

1998-07-29

105

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

106

High Precision Prediction of Functional Sites in Protein Structures  

PubMed Central

We address the problem of assigning biological function to solved protein structures. Computational tools play a critical role in identifying potential active sites and informing screening decisions for further lab analysis. A critical parameter in the practical application of computational methods is the precision, or positive predictive value. Precision measures the level of confidence the user should have in a particular computed functional assignment. Low precision annotations lead to futile laboratory investigations and waste scarce research resources. In this paper we describe an advanced version of the protein function annotation system FEATURE, which achieved 99% precision and average recall of 95% across 20 representative functional sites. The system uses a Support Vector Machine classifier operating on the microenvironment of physicochemical features around an amino acid. We also compared performance of our method with state-of-the-art sequence-level annotator Pfam in terms of precision, recall and localization. To our knowledge, no other functional site annotator has been rigorously evaluated against these key criteria. The software and predictive models are incorporated into the WebFEATURE service at http://feature.stanford.edu/wf4.0-beta. PMID:24632601

Buturovic, Ljubomir; Wong, Mike; Tang, Grace W.; Altman, Russ B.; Petkovic, Dragutin

2014-01-01

107

Experimental Hypersonic Aerodynamic Characteristics of the 2001 Mars Surveyor Precision Lander with Flap  

NASA Technical Reports Server (NTRS)

Aerodynamic wind-tunnel screening tests were conducted on a 0.029 scale model of a proposed Mars Surveyor 2001 Precision Lander (70 deg half angle spherically blunted cone with a conical afterbody). The primary experimental objective was to determine the effectiveness of a single flap to trim the vehicle at incidence during a lifting hypersonic planetary entry. The laminar force and moment data, presented in the form of coefficients, and shock patterns from schlieren photography were obtained in the NASA Langley Aerothermodynamic Laboratory for post-normal shock Reynolds numbers (based on forebody diameter) ranging from 2,637 to 92,350, angles of attack ranging from 0 tip to 23 degrees at 0 and 2 degree sideslip, and normal-shock density ratios of 5 and 12. Based upon the proposed entry trajectory of the 2001 Lander, the blunt body heavy gas tests in CF, simulate a Mach number of approximately 12 based upon a normal shock density ratio of 12 in flight at Mars. The results from this experimental study suggest that when traditional means of providing aerodynamic trim for this class of planetary entry vehicle are not possible (e.g. offset c.g.), a single flap can provide similar aerodynamic performance. An assessment of blunt body aerodynamic effects attributed to a real gas were obtained by synergistic testing in Mach 6 ideal-air at a comparable Reynolds number. From an aerodynamic perspective, an appropriately sized flap was found to provide sufficient trim capability at the desired L/D for precision landing. Inviscid hypersonic flow computations using an unstructured grid were made to provide a quick assessment of the Lander aerodynamics. Navier-Stokes computational predictions were found to be in very good agreement with experimental measurement.

Horvath, Thomas J.; OConnell, Tod F.; Cheatwood, F. McNeil; Prabhu, Ramadas K.; Alter, Stephen J.

2002-01-01

108

High-Precision Entropy Values for Spanning Trees in Lattices  

E-print Network

Shrock and Wu have given numerical values for the exponential growth rate of the number of spanning trees in Euclidean lattices. We give a new technique for numerical evaluation that gives much more precise values, together with rigorous bounds on the accuracy. In particular, the new values resolve one of their questions.

Jessica L. Felker; Russell Lyons

2003-04-29

109

A New High Precision Differential Spectrometer: Construction, Characteristics, And Capabilities  

NASA Astrophysics Data System (ADS)

A unique differential spectrometer has been developed for the quantitative examination of surfaces. It combines a tuneable pulsed dye laser light source, a flexible precision sample holder, silicon photodiode-in-integrating sphere detectors, and a desktop computer controller/analyzer. This combination enables very precise measurements--twiddlel% systematic errors and twiddle.02% random errors in reflection and transmission measurements. The spectrome-ter has been applied to the investigation of the structure of various component films used in semiconductor devices and in a basic study of the molecular-molecular interactions of dyes adsorbed on surfaces. With only minor modifications, this device can make transient spectroscopy measurements with a resolution of twiddle 10 nsec. It can also be used for a variety of modulation spectroscopies. We will be exploring those areas in the future.

Stephens, R. B.; Sorensen, G. K.

1981-04-01

110

High Precision Formation for Two-Photon 3D Microfabrication  

Microsoft Academic Search

Two-photon 3D microfabrication has become one research focus in MEMS field. The main factors influencing the fabrication precision are discussed in this paper. One factor is decided by the characteristics of the two-photon polymerization, includes the power of the femtosecond (fs) laser, the exposing time and the overlap ratio, etc. The other is mainly induced by the movement error of

Guohua Gao; Yu Zhu; Guanghong Duang; Yingxing Fang

2006-01-01

111

Ion source for high-precision mass spectrometry  

DOEpatents

The invention is directed to a method for increasing the precision of positive-ion relative abundance measurements conducted in a sector mass spectrometer having an ion source for directing a beam of positive ions onto a collimating slit. The method comprises incorporating in the source an electrostatic lens assembly for providing a positive-ion beam of circular cross section for collimation by the slit. 2 figures, 3 tables.

Todd, P.J.; McKown, H.S.; Smith, D.H.

1982-04-26

112

Ion source for high-precision mass spectrometry  

DOEpatents

The invention is directed to a method for increasing the precision of positive-ion relative abundance measurements conducted in a sector mass spectrometer having an ion source for directing a beam of positive ions onto a collimating slit. The method comprises incorporating in the source an electrostatic lens assembly for providing a positive-ion beam of circular cross section for collimation by the slit.

Todd, Peter J. (Oak Ridge, TN); McKown, Henry S. (Oak Ridge, TN); Smith, David H. (Oak Ridge, TN)

1984-01-01

113

Analysis on working status of support device with 3-point used in high precision system  

NASA Astrophysics Data System (ADS)

The support device with 3-point are widely used in many kinds of support systems. However, some problems will emerge when the device is used in high precision system. For example, in the self-adaptive optical system, the different deformation of each support point will cause the dissimilar slope of the supported part of the system, will cause the position error of segment mirror. This paper, using elastic mechanics theory to calculate the elastic deformation, calculates the elasticity deformation of steel balls in the device; based on the principle of optical auto-collimation, tests the related deformations of the three support points under different normal loads; according to the calculation and the experimentation, compares and analyzes the results of calculation and experimentation, sums up the relationship between deformation and support sphere diameter and load value; lastly, proposes the principia to determine the diameter of the balls in high precision system, and provides reformative scheme to design a better support devices with 3-point. The results of this paper have been used in the design and development of self-adaptive optical system.

Wang, Zhi-shan; Zhao, Yue-jin

2009-11-01

114

Gauges for Highly Precise Metrology of a Compound Mirror  

NASA Technical Reports Server (NTRS)

Three optical gauges have been developed for guiding the assembly and measuring precisely the reflecting surfaces of a compound mirror that comprises a corner-cube retroreflector glued in a hole on a flat mirror. In the specific application for which the gauges were developed, the compound mirror is part of a siderostat in a stellar interferometer. The flat-mirror portion of the compound mirror is the siderostat mirror; the retroreflector portion of the compound mirror is to be used, during operation of the interferometer, to monitor the location of the siderostat mirror surface relative to other optical surfaces of the interferometer. Nominally, the optical corner of the retroreflector should lie precisely on the siderostat mirror surface, but this precision cannot be achieved in fabrication: in practice, there remains some distance between the optical corner and the siderostat mirror surface. For proper operation of the interferometer, it is required to make this distance as small as possible and to know this distance within 1 nm. The three gauges make it possible to satisfy these requirements.

Gursel, Yekta

2005-01-01

115

Vibratory response modeling and verification of a high precision optical positioning system.  

SciTech Connect

A generic vibratory-response modeling program has been developed as a tool for designing high-precision optical positioning systems. Based on multibody dynamics theory, the system is modeled as rigid-body structures connected by linear elastic elements, such as complex actuators and bearings. The full dynamic properties of each element are determined experimentally or theoretically, then integrated into the program as inertial and stiffness matrices. Utilizing this program, the theoretical and experimental verification of the vibratory behavior of a double-multilayer monochromator support and positioning system is presented. Results of parametric design studies that investigate the influence of support floor dynamics and highlight important design issues are also presented. Overall, good matches between theory and experiment demonstrate the effectiveness of the program as a dynamic modeling tool.

Barraza, J.; Kuzay, T.; Royston, T. J.; Shu, D.

1999-06-18

116

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

117

High-frequency impedance analysis for NDE of complex precision parts  

NASA Astrophysics Data System (ADS)

A high-frequency, impedance-based structural health monitoring technique developed at the Center for Intelligent Material Systems and Structures (CIMSS) has been extended to the NDE of complex precision parts. Like many other non-destructive evaluation (NDE) techniques, this method relies on the detection of change in the dynamic properties of the structure when damage occurs. This NDE technique relies on the measurement of the electrical impedance at high frequencies (100 kHz - 275 kHz) with bonded non-intrusive piezoelectric actuator/sensors. Since the electrical and mechanical impedances of the bonded actuator/sensor are directly coupled, the proposed NDE method is able to detect incipient damage in the structure. Gears were chosen as complex precision parts for the experimental procedure because of their tight tolerances, high quality, and broad use. The goal is to show that incipient damage in the gear teeth, which are an extension of the cylindrical base structure, can be monitored. The most common types of damage in gears, i.e., abrasive wear and bending fatigue, were successfully detected. The impedance measurements before and after damage were converted into a scalar damage metric, which was used to detect the presence of damage when a threshold value was exceeded. Also, quality inspection was successfully demonstrated using the impedance-based technique.

Lalande, Frederic; Rogers, Craig A.; Childs, Brian W.; Chaudhry, Zaffir A.

1996-05-01

118

High-precision molecular dynamics simulation of UO2-PuO2: pair potentials comparison  

E-print Network

Our series of articles is devoted to high-precision molecular dynamics simulation of mixed actinide-oxide (MOX) fuel in the rigid ions approximation using high-performance graphics processors (GPU). In the first article we assess 10 most relevant interatomic sets of pair potentials (SPP) by reproduction of solid phase properties of uranium dioxide (UO2) - temperature dependences of the lattice constant, bulk modulus, enthalpy and heat capacity. Measurements were performed with 1K accuracy in a wide temperature range from 300K up to melting point. The best results are demonstrated by two recent SPPs MOX-07 and Yakub-09, which both had been fitted to the recommended thermal expansion in the range of temperatures 300-3100K. Compared with them, the widely used SPPs Basak-03 and Morelon-03 reproduce the experimental data noticeably worse at temperatures above 2500K.

Potashnikov, S I; Nekrasov, K A; Kupryazhkin, A Ya

2011-01-01

119

A high precision, compact electromechanical ground rotation sensor.  

PubMed

We present a mechanical rotation sensor consisting of a balance pivoting on a tungsten carbide knife edge. These sensors are important for precision seismic isolation systems, as employed in land-based gravitational wave interferometers and for the new field of rotational seismology. The position sensor used is an air-core linear variable differential transformer with a demonstrated noise floor of 1 × 10?¹¹ m/?Hz. We describe the instrument construction and demonstrate low noise operation with a noise floor upper bound of 5.7 × 10?? rad/?Hz at 10 mHz and 6.4 × 10?¹? rad/?Hz at 0.1 Hz. The performance of the knife edge hinge is compatible with a behaviorur free of noise from dislocation self-organized criticality. PMID:24880388

Dergachev, V; DeSalvo, R; Asadoor, M; Bhawal, A; Gong, P; Kim, C; Lottarini, A; Minenkov, Y; Murphy, C; O'Toole, A; Peña Arellano, F E; Rodionov, A V; Shaner, M; Sobacchi, E

2014-05-01

120

Applied high resolution digital control for universal precision systems  

E-print Network

This thesis describes the design and characterization of a high-resolution analog interface for dSPACE digital control systems and a high-resolution, high-speed data acquisition and control system. These designs are intended ...

Gawlik, Aaron John

2008-01-01

121

HIGH-PRECISION DYNAMICAL MASSES OF VERY LOW MASS BINARIES  

SciTech Connect

We present the results of a three year monitoring program of a sample of very low mass (VLM) field binaries using both astrometric and spectroscopic data obtained in conjunction with the laser guide star adaptive optics system on the W. M. Keck II 10 m telescope. Among the 24 systems studied, 15 have undergone sufficient orbital motion, allowing us to derive their relative orbital parameters and hence their total system mass. These measurements more than double the number of mass measurements for VLM objects, and include the most precise mass measurement to date (<2%). Among the 11 systems with both astrometric and spectroscopic measurements, six have sufficient radial velocity variations to allow us to obtain individual component masses. This is the first derivation of the component masses for five of these systems. Altogether, the orbital solutions of these low mass systems show a correlation between eccentricity and orbital period, consistent with their higher mass counterparts. In our primary analysis, we find that there are systematic discrepancies between our dynamical mass measurements and the predictions of theoretical evolutionary models (TUCSON and LYON) with both models either underpredicting or overpredicting the most precisely determined dynamical masses. These discrepancies are a function of spectral type, with late-M through mid-L systems tending to have their masses underpredicted, while one T-type system has its mass overpredicted. These discrepancies imply that either the temperatures predicted by evolutionary and atmosphere models are inconsistent for an object of a given mass, or the mass-radius relationship or cooling timescales predicted by the evolutionary models are incorrect. If these spectral-type trends are correct and hold into the planetary mass regime, the implication is that the masses of directly imaged extrasolar planets are overpredicted by the evolutionary models.

Konopacky, Q. M.; Ghez, A. M.; McLean, I. S. [University of California, Los Angeles, Division of Astronomy and Astrophysics, Los Angeles, CA 90095-1562 (United States); Barman, T. S. [Lowell Observatory, 1400 W. Mars Hill Road, Flagstaff, AZ 86001 (United States); Rice, E. L. [American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192 (United States); Bailey, J. I. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48105 (United States); White, R. J. [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303 (United States); Duchene, G., E-mail: konopacky1@llnl.go, E-mail: ghez@astro.ucla.ed, E-mail: mclean@astro.ucla.ed, E-mail: barman@lowell.ed, E-mail: baileyji@umich.ed, E-mail: white@chara.gsu.ed, E-mail: gduchene@berkeley.ed [Astronomy Department, University of California, Berkeley, 601 Campbell Hall, Berkeley, CA 94720-3411 (United States)

2010-03-10

122

High-precision distribution of highly stable optical pulse trains with 8.8 × 10?¹? instability.  

PubMed

The high-precision distribution of optical pulse trains via fibre links has had a considerable impact in many fields. In most published work, the accuracy is still fundamentally limited by unavoidable noise sources, such as thermal and shot noise from conventional photodiodes and thermal noise from mixers. Here, we demonstrate a new high-precision timing distribution system that uses a highly precise phase detector to obviously reduce the effect of these limitations. Instead of using photodiodes and microwave mixers, we use several fibre Sagnac-loop-based optical-microwave phase detectors (OM-PDs) to achieve optical-electrical conversion and phase measurements, thereby suppressing the sources of noise and achieving ultra-high accuracy. The results of a distribution experiment using a 10-km fibre link indicate that our system exhibits a residual instability of 2.0 × 10(-15) at1?s and8.8 × 10(-19) at 40,000?s and an integrated timing jitter as low as 3.8?fs in a bandwidth of 1?Hz to 100?kHz. This low instability and timing jitter make it possible for our system to be used in the distribution of optical-clock signals or in applications that require extremely accurate frequency/time synchronisation. PMID:24870442

Ning, B; Zhang, S Y; Hou, D; Wu, J T; Li, Z B; Zhao, J Y

2014-01-01

123

Experimental high-speed network  

NASA Astrophysics Data System (ADS)

Many existing local area networking protocols currently applied in medical imaging were originally designed for relatively low-speed, low-volume networking. These protocols utilize small packet sizes appropriate for text based communication. Local area networks of this type typically provide raw bandwidth under 125 MHz. These older network technologies are not optimized for the low delay, high data traffic environment of a totally digital radiology department. Some current implementations use point-to-point links when greater bandwidth is required. However, the use of point-to-point communications for a total digital radiology department network presents many disadvantages. This paper describes work on an experimental multi-access local area network called XFT. The work includes the protocol specification, and the design and implementation of network interface hardware and software. The protocol specifies the Physical and Data Link layers (OSI layers 1 & 2) for a fiber-optic based token ring providing a raw bandwidth of 500 MHz. The protocol design and implementation of the XFT interface hardware includes many features to optimize image transfer and provide flexibility for additional future enhancements which include: a modular hardware design supporting easy portability to a variety of host system buses, a versatile message buffer design providing 16 MB of memory, and the capability to extend the raw bandwidth of the network to 3.0 GHz.

McNeill, Kevin M.; Klein, William P.; Vercillo, Richard; Alsafadi, Yasser H.; Parra, Miguel V.; Dallas, William J.

1993-09-01

124

Achieving high-precision ground-based photometry for transiting exoplanets  

E-print Network

Achieving high-precision ground-based photometry for transiting exoplanets Olivier Guyona, USA ABSTRACT Detection of transiting exoplanets requires high precision photometry, at the percent opportunity for exoplanet transit detection. We have recently assembled a prototype DSLR-based robotic imaging

Guyon, Olivier

125

High-precision control of piezoelectric nanopositioning stages using hysteresis compensator and disturbance observer  

NASA Astrophysics Data System (ADS)

This paper proposes a novel high-performance control scheme with hysteresis compensator and disturbance observer for high-precision motion control of a nanopositioning stage driven by a piezoelectric stack actuator (PSA). In the developed control scheme, a real-time inverse hysteresis compensator (IHC) with the modified Prandtl-Ishlinskii model is firstly designed to compensate for the asymmetric hysteresis nonlinearity of the PSA. Due to the imperfect compensation, the dynamics behaviors of the PSA-actuated stage with the IHC can be treated as a linear dynamic system plus a lumped disturbance term. Owing to the unknown nature of this lumped disturbance term, a disturbance observer (DOB) is used as a means for disturbance rejection. With the DOB, a tracking controller is finally designed and implemented to stabilize the position error. To verify the proposed control scheme, a real-time experimental platform with a PSA-actuated nanopositioning stage is built, and extensive experimental tests are performed. The comparative experimental results demonstrate the effectiveness and improved performance of the developed control approach in terms of the maximum-value errors, root-mean-square-value errors and hysteresis compensation.

Gu, Guo-Ying; Zhu, Li-Min; Su, Chun-Yi

2014-10-01

126

Study on mechanism and process of ion beam machining on high-precision large optical surfaces  

NASA Astrophysics Data System (ADS)

Ion beam machining has become an important means adopted to high-precision large optical mirror processing. This study has conducted a bitmap-style model, calculation and analysis on low-energy Ar+ ion beam sputtering optical surface, based on Sigmund Theory and the CCOS principle. We have obtained the relationship of the removal function and the removal rate with major technological parameters of ion beam machining (e.g. dwell time, work distance, ion energy, etc.) also via orthogonal experiments of single point removal. Results indicated that the removal rate of amorphous SiO2 (fused silica) by Ar+ ions with 600~1200 electron volts increases with the increase of ion energy and dwell time at different extents, decreases exponentially with the increase in work distance. On the basis of computational analysis and experimental investigations, we optimized process conditions and further figured the plane mirror with the clear aperture of 130 millimeters, utilizing technologically optimized low-energy Ar+ ion beam machining. Eventually we obtained the high-precision figure shape with the post-machined surface roughness of 0.43~0.44 nm rms and the post-machined figure error of 1 nm rms.

Liang, Xiao; Gu, Yongqiang; Wang, Xiang; Ma, Zhanlong; Sui, Yongxin; Zheng, Jinjin

2014-08-01

127

Mold, flow, and economic considerations in high temperature precision casting  

E-print Network

Casting high temperature alloys that solidify through a noticeable two phase region, specifically platinum-ruthenium alloys, is a particularly challenging task due to their high melting temperature and this necessitates ...

Humbert, Matthew S

2013-01-01

128

The Mainz high-precision proton form factor measurement  

NASA Astrophysics Data System (ADS)

New precise results from a measurement of the elastic electron-proton scattering cross section performed at the Mainz Microtron MAMI are presented. About 1400 cross sections were measured with negative four-momentum transfers squared up to Q2 = 1(GeV/c)2 with statistical errors below 0.2%. The electric and magnetic form factors of the proton were extracted with fits of a large variety of form factor models directly to the cross sections. The form factors show some features at the scale of the pion cloud. The charge and magnetic radii are determined to be 1/2 = 0.879(5)stat.(4)syst.(2)model(4)group fm and 1/2 = 0.777(13)stat.(9)syst.(5)model(2)group fm. Extending the data set with external data, a continuous, simultaneous fit to the world data set up to Q2 = 10(GeV/c)2 is achieved.

Bernauer, Jan C.; A1 Collaboration

2013-10-01

129

High-precision timeline for Earth's most severe extinction  

PubMed Central

The end-Permian mass extinction was the most severe loss of marine and terrestrial biota in the last 542 My. Understanding its cause and the controls on extinction/recovery dynamics depends on an accurate and precise age model. U-Pb zircon dates for five volcanic ash beds from the Global Stratotype Section and Point for the Permian-Triassic boundary at Meishan, China, define an age model for the extinction and allow exploration of the links between global environmental perturbation, carbon cycle disruption, mass extinction, and recovery at millennial timescales. The extinction occurred between 251.941 ± 0.037 and 251.880 ± 0.031 Mya, an interval of 60 ± 48 ka. Onset of a major reorganization of the carbon cycle immediately precedes the initiation of extinction and is punctuated by a sharp (3‰), short-lived negative spike in the isotopic composition of carbonate carbon. Carbon cycle volatility persists for ?500 ka before a return to near preextinction values. Decamillenial to millennial level resolution of the mass extinction and its aftermath will permit a refined evaluation of the relative roles of rate-dependent processes contributing to the extinction, allowing insight into postextinction ecosystem expansion, and establish an accurate time point for evaluating the plausibility of trigger and kill mechanisms. PMID:24516148

Burgess, Seth D.; Bowring, Samuel; Shen, Shu-zhong

2014-01-01

130

High-precision timeline for Earth's most severe extinction.  

PubMed

The end-Permian mass extinction was the most severe loss of marine and terrestrial biota in the last 542 My. Understanding its cause and the controls on extinction/recovery dynamics depends on an accurate and precise age model. U-Pb zircon dates for five volcanic ash beds from the Global Stratotype Section and Point for the Permian-Triassic boundary at Meishan, China, define an age model for the extinction and allow exploration of the links between global environmental perturbation, carbon cycle disruption, mass extinction, and recovery at millennial timescales. The extinction occurred between 251.941 ± 0.037 and 251.880 ± 0.031 Mya, an interval of 60 ± 48 ka. Onset of a major reorganization of the carbon cycle immediately precedes the initiation of extinction and is punctuated by a sharp (3‰), short-lived negative spike in the isotopic composition of carbonate carbon. Carbon cycle volatility persists for ?500 ka before a return to near preextinction values. Decamillenial to millennial level resolution of the mass extinction and its aftermath will permit a refined evaluation of the relative roles of rate-dependent processes contributing to the extinction, allowing insight into postextinction ecosystem expansion, and establish an accurate time point for evaluating the plausibility of trigger and kill mechanisms. PMID:24516148

Burgess, Seth D; Bowring, Samuel; Shen, Shu-zhong

2014-03-01

131

Application of GPS in a high precision engineering survey network  

SciTech Connect

A GPS satellite survey was carried out with the Macrometer to support construction at the Stanford Linear Accelerator Center (SLAC). The network consists of 16 stations of which 9 stations were part of the Macrometer network. The horizontal and vertical accuracy of the GPS survey is estimated to be 1 to 2 mm and 2 to 3 mm respectively. The horizontal accuracy of the terrestrial survey, consisting of angles and distances, equals that of the GPS survey only in the ''loop'' portion of the network. All stations are part of a precise level network. The ellipsoidal heights obtained from the GPS survey and the orthometric heights of the level network are used to compute geoid undulations. A geoid profile along the linac was computed by the National Geodetic Survey in 1963. This profile agreed with the observed geoid within the standard deviation of the GPS survey. Angles and distances were adjusted together (TERRA), and all terrestrial observations were combined with the GPS vector observations in a combination adjustment (COMB). A comparison of COMB and TERRA revealed systematic errors in the terrestrial solution. A scale factor of 1.5 ppM +- .8 ppM was estimated. This value is of the same magnitude as the over-all horizontal accuracy of both networks. 10 refs., 3 figs., 5 tabs.

Ruland, R.; Leick, A.

1985-04-01

132

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

133

High-precision control of LSRM based X-Y table for industrial applications.  

PubMed

The design of an X-Y table applying direct-drive linear switched reluctance motor (LSRM) principle is proposed in this paper. The proposed X-Y table has the characteristics of low cost, simple and stable mechanical structure. After the design procedure is introduced, an adaptive position control method based on online parameter identification and pole-placement regulation scheme is developed for the X-Y table. Experimental results prove the feasibility and its priority over a traditional PID controller with better dynamic response, static performance and robustness to disturbances. It is expected that the novel two-dimensional direct-drive system find its applications in high-precision manufacture area. PMID:22981303

Pan, J F; Cheung, Norbert C; Zou, Yu

2013-01-01

134

A High Precision Feature Based on LBP and Gabor Theory for Face Recognition  

PubMed Central

How to describe an image accurately with the most useful information but at the same time the least useless information is a basic problem in the recognition field. In this paper, a novel and high precision feature called BG2D2LRP is proposed, accompanied with a corresponding face recognition system. The feature contains both static texture differences and dynamic contour trends. It is based on Gabor and LBP theory, operated by various kinds of transformations such as block, second derivative, direct orientation, layer and finally fusion in a particular way. Seven well-known face databases such as FRGC, AR, FERET and so on are used to evaluate the veracity and robustness of the proposed feature. A maximum improvement of 29.41% is achieved comparing with other methods. Besides, the ROC curve provides a satisfactory figure. Those experimental results strongly demonstrate the feasibility and superiority of the new feature and method. PMID:23552103

Xia, Wei; Yin, Shouyi; Ouyang, Peng

2013-01-01

135

Highly Precise Micropositioning Task using a Direct Visual Servoing Scheme  

E-print Network

integration of high-performance elec- tronic devices, microelectromechanical structures (MEMS consider the use of the vision sensor to control the behavior of the robotic structure of the microassembly), and optoelectronic devices onto the same substrate is im- portant for the development of low-cost, high performance

Paris-Sud XI, Université de

136

Closed loop high precision position control system with optical scale  

Microsoft Academic Search

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.

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

2008-01-01

137

High Precision Fe Isotope Analysis in low Concentration Samples by High Resolution MC-ICPMS  

NASA Astrophysics Data System (ADS)

Iron availability has been shown to be the main limitation factor for phytoplankton growth in the ocean. However, due to the limitation of analytical technique, the database of dissolved Fe concentrations and isotope ratio distribution in the ocean is still very limited. In particular, the iron sources to the ocean remain uncertain. Aeolian dust from the continental is considered as the primary source, also the digenetic dissolution at the continental margins is proposed to contribute significant portion of iron content of the sea surface water. The field of Fe isotope geochemistry has seen important developments in methodology and scope since the advent of Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS). Although increasing the number of replicates in High Resolution MC-ICPMS reduces the uncertainty related to instability in instrumental mass bias and counting statistics, many other parameters include mass fractionation during column separation, matrix effect in ICPMS analysis and the presence of isobaric interferences can affect the precision and accuracy of Fe isotopic analyses. In this study, a high precision analytical method of Fe isotope measurement for low concentration samples was developed using HR-MC-ICPMS. Several parameters that may affect the accuracy and precision of 56Fe/54Fe result such as background, instrumental mass discrimination, isobaric interferences, type of introduction system and acid molarity were identified and evaluated. External precisions better than 0.04‰ for ?56Fe can be achieve using only 10ng of iron sample with APEX and X-cone as introduction system. Significant improvement in terms of sample size was made. This method can be applied on very low concentration samples such as coral and seawater.

Chung, C.; Wu, J.; You, C.

2009-12-01

138

HIGH PRECISION ASTROMETRY WITH A DIFFRACTIVE PUPIL TELESCOPE  

E-print Network

80304, USA Ruslan Belikov NASA Ames Research Center, Moffett Field, CA 94035, USA ABSTRACT #12;­ 2 enables sub-µas astrometry without relying on the accurate pointing, external metrology or high stability

Guyon, Olivier

139

The accuracy and precision of the experimental ?-determination in the 1\\/E 1+? epithermal reactor-neutron spectrum  

Microsoft Academic Search

Some methods for the experimental ?-determination in the 1\\/E1+? epithermal reactorneutron spetrum are critically compared with respect to their accuracy and precision. The analysis is based\\u000a on the error propagation theory. Besides the general formulae numerical examples are elaborated for specific conditions in\\u000a the Thetis reactor (Gent) and the WWR-M reactor (Budapest).

F. De Corte; K. Sordo-El Hammami; L. Moens; A. Simonits; A. De Wispelaere; J. Hoste

1981-01-01

140

Development of a high-precision surface metrology system using structured light projection  

Microsoft Academic Search

In this paper, we present a high-precision surface metrology system based on structured light projection. Gray code patterns are projected onto the object surface by a DMD projection device and a CCD camera captures the distorted pattern images. For the purpose of precision measurement, a 3D mathematical model is proposed for the system and a calibration process is developed to

Ming-June Tsai; Chuan-Cheng Hung

2005-01-01

141

High-precision CO2 isotopologue spectrometer with a difference-frequency-generation laser source  

E-print Network

High-precision CO2 isotopologue spectrometer with a difference-frequency-generation laser source A precision laser spectrometer for the detection of CO2 isotopes is reported. The spectrometer measures the fundamental absorption signatures of 13 C and 12 C isotopes in CO2 at 4.32 m using a tunable mid-IR laser

142

High precision and continuous optical transport using a standing wave optical  

E-print Network

High precision and continuous optical transport using a standing wave optical line trap Vassili://chaos.utexas.edu/ Abstract: We introduce the Standing Wave Optical Line Trap (SWOLT) as a novel tool for precise optical nanoparticles. © 2011 Optical Society of America OCIS codes: (000.2170) Equipment and techniques; (120

Texas at Austin. University of

143

High-precision automatic online measurement system of engine block top surface holes  

NASA Astrophysics Data System (ADS)

The measurement of holes in the engine block top surface determines the general coupling effect of the engine. All of these holes are strictly restricted by the requirements of the dimensional tolerance and the geometrical tolerance, which determines the final engine quality. At present, these holes are measured mostly by the coordinate measuring machine (CMM) in the production line, and meeting the industry demands of automation, rapidity, and online testing with the method is difficult. A new rapid solution measuring the holes in the engine block top surface is proposed, which is based on the combination of multiple visual sensors. The flexible location method of the block is designed, and the global data fusion model based on multiple visual sensors is studied. Finally, the unified correction model of the lens distortion and the system inclination is proposed, and a revised system model with more precision is researched. The CMM measures the holes sizes and the spatial relationship between holes, and the data obtained are substituted into the global data fusion model to complete the system on-site rapid calibration. The experimental results show that the scheme is feasible. The measurement system can meet the production line needs of intelligence, rapidity, and high precision.

Yongqiang, Shi; Changku, Sun; Yukun, Ma; Hongxu, Duan; Peng, Wang

2012-05-01

144

Theory of high-precision Zeeman effect in diatomic molecules  

Microsoft Academic Search

A theoretical description of the Zeeman effect in a diatomic molecule is given on the basis of exact numerical diagonalization of the perturbation matrix. In this way it is also possible to include the fine and hyperfine structures to the desired degree of accuracy, and this is highly important for a complete theory of the molecular Zeeman effect. The present

L. Veseth

1976-01-01

145

HYDRA: High Speed Simulation Architecture for Precision Spacecraft Formation Flying  

NASA Technical Reports Server (NTRS)

This viewgraph presentation describes HYDRA, which is architecture to facilitate high-fidelity and real-time simulation of formation flying missions. The contents include: 1) Motivation; 2) Objective; 3) HYDRA-Description and Overview; 4) HYDRA-Hierarchy; 5) Communication in HYDRA; 6) Simulation Specific Concerns in HYDRA; 7) Example application (Formation Acquisition); and 8) Sample Problem Results.

Martin, Bryan J.; Sohl, Garett A.

2003-01-01

146

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

147

Precision mass spectrometry of highly charged ions with TITAN. Status and outlook  

NASA Astrophysics Data System (ADS)

High-precision and accurate atomic mass measurements are vital for the description of nuclear structure, investigations of nuclear astrophysical processes, and tests of fundamental symmetries. We report on mass measurements of short-lived highly charged ions using the TITAN Penning-trap mass spectrometer at TRIUMF. To increase the overall efficiency and precision of the mass measurement of highly charged ions, an addition to the TITAN system, the novel cooler Penning trap CPET is discussed.

Simon, V. V.; Chaudhuri, A.; Chowdhury, U.; Gallant, A. T.; Kwiatkowski, A. A.; Lennarz, A.; Macdonald, T. D.; Schultz, B. E.; Simon, M. C.; Andreoiu, C.; Gwinner, G.; Dilling, J.

2014-06-01

148

High-precision covariant one-boson-exchange potentials for np scattering below 350 MeV  

SciTech Connect

Using the Covariant Spectator Theory (CST), we have found One-Boson-Exchange (OBE) potentials that fit the 2006 world np data below 350 MeV with a chi2/Ndata very close to 1, for a total of 3788 data. Our potentials have significantly fewer adjustable parameters than previous high-precision potentials, and they also reproduce the experimental triton binding energy without introducing additional irreducible three-nucleon forces.

Franz Gross; Alfred Stadler

2007-09-10

149

Topographic SAR interferometry formulation for high-precision DEM generation  

Microsoft Academic Search

In repeat-pass synthetic aperture radar (SAR) interferometry, the approximations, allowing the phase-to-height conversion, prevent high-resolution mapped relief. In this paper, we present a more general and exact formulation giving a new relationship between the interferogram phase and the target height. It is based on the interferometric SAR geometry and on a better expansion of the path length difference between the

Riadh Abdelfattah; Jean Marie Nicolas

2002-01-01

150

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

151

Improving the precision of high-rate GPS  

NASA Astrophysics Data System (ADS)

In order to improve the accuracy of high-rate (1 Hz) displacements for geophysical applications such as seismology it is important to reduce systematic errors at seismic frequencies. One such GPS error source that overlaps with seismic frequencies and is not currently modeled is multipath. This study investigates the frequencies and repetition of multipath in high-rate GPS time series in order to maximize the effectiveness of techniques relying upon the geometric repeatability of GPS satellite orbits. The implementation of the aspect repeat time adjustment (ARTA) method described here uses GPS position time series to estimate time-varying and site-dependent shifts. As demonstrated for high-rate GPS sites in southern California this technique significantly reduces positioning noise at periods from 20 to 1000 s. For a 12-hour time series, ARTA methods improve the standard deviation of the north component from 8.2 to 5.1 mm and the east component from 6.3 to 4.0 mm. After applying ARTA corrections, common mode errors are removed by stacking. This method further improves the standard deviations to 3.0 and 2.6 mm for the north and east components, respectively.

Larson, Kristine M.; Bilich, Andria; Axelrad, Penina

2007-05-01

152

Precision rectification of high resolution satellite imagery without ephemeris data  

NASA Astrophysics Data System (ADS)

The huge capability of high resolution satellite imageries (HRSI), that includes spatial, spectral, temporal and radiometric resolutions as well as stereoscopic vision introduces them as a powerful new source for the Photogrammetry, Remote Sensing and GIS communities. High resolution data increases the need for higher accuracy of data modeling. The satellite orbit, position, attitude angles and interior orientation parameters have to be adjusted in the geometrical model to achieve optimal accuracy with the use of a minimum number of Ground Control Points (GCPs). But most high resolution satellite vendors do not intend to publish their sensor models and ephemeris data. There is consequently a need for a range of alternative, practical approaches for extracting accurate 2D and 3D terrain information from HRSI. The flexibility and good accuracy of the alternative models demonstrated with KFA-1000 and the well-known SPOT level 1A images. A block of eight KFA-1000 space photos in two strips with 60% longitudinal overlap and 15% lateral sidelap and SPOT image with rational function, DLT, 2D projective, polynomials, affine, conformal, multiquadric and finite element methods were used in the test. The test areas cover parts of South and West of Iran. Considering the quality of GCPs, the best result was found with the DLT method with a RMSE of 8.44 m for the KFA-1000 space photos.

Sadeghian, Saeid; Valadan Zoej, Mohammad Javad; Delavar, Mahmoud Reza; Abootalebi, Ahmad

153

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

154

High-precision metrology of highly charged ions via relativistic resonance fluorescence.  

PubMed

Resonance fluorescence of laser-driven highly charged ions is investigated with regard to precisely measuring atomic properties. For this purpose an ab initio approach based on the Dirac equation is employed that allows for studying relativistic ions. These systems provide a sensitive means to test correlated relativistic dynamics, quantum electrodynamic phenomena and nuclear effects by applying x-ray lasers. We show how the narrowing of sidebands in the x-ray fluorescence spectrum by interference due to an additional optical driving can be exploited to determine atomic dipole or multipole moments to unprecedented accuracy. PMID:21405269

Postavaru, O; Harman, Z; Keitel, C H

2011-01-21

155

P-values in genomics: Apparent precision masks high uncertainty.  

PubMed

Scientists often interpret P-values as measures of the relative strength of statistical findings. This is common practice in large-scale genomic studies where P-values are used to choose which of numerous hypothesis test results should be pursued in subsequent research. In this study, we examine P-value variability to assess the degree of certainty P-values provide. We develop prediction intervals for the P-value in a replication study given the P-value observed in an initial study. The intervals depend on the initial value of P and the ratio of sample sizes between the initial and replication studies, but not on the underlying effect size or initial sample size. The intervals are valid for most large-sample statistical tests in any context, and can be used in the presence of single or multiple tests. While P-values are highly variable, future P-value variability can be explicitly predicted based on a P-value from an initial study. The relative size of the replication and initial study is an important predictor of the P-value in a subsequent replication study. We provide a handy calculator implementing these results and apply them to a study of Alzheimer's disease and recent findings of the Cross-Disorder Group of the Psychiatric Genomics Consortium. This study suggests that overinterpretation of very significant, but highly variable, P-values is an important factor contributing to the unexpectedly high incidence of non-replication. Formal prediction intervals can also provide realistic interpretations and comparisons of P-values associated with different estimated effect sizes and sample sizes. PMID:24419042

Lazzeroni, L C; Lu, Y; Belitskaya-Lévy, I

2014-12-01

156

High speed precision motion strategies for lightweight structures  

NASA Technical Reports Server (NTRS)

Work during the recording period proceeded along the lines of the proposal, i.e., three aspects of high speed motion planning and control of flexible structures were explored: fine motion control, gross motion planning and control, and automation using light weight arms. In addition, modeling the large manipulator arm to be used in experiments and theory has lead to some contributions in that area. These aspects are reported below. Conference, workshop and journal submissions, and presentations related to this work were seven in number, and are listed. Copies of written papers and abstracts are included.

Book, Wayne J.

1987-01-01

157

High precision fractionator for use with density gradient ultracentrifugation.  

PubMed

The recent application of density gradient ultracentrifugation (DGU) for structural sorting of single-walled carbon nanotube samples has created a need for highly selective extraction of closely spaced layers formed in the centrifuged tube. We describe a novel computer-controlled device designed for this purpose. Through the use of fine needles, systematic needle motions, and slow flow rates, multiple sample layers can be aspirated under program control with minimal cross contamination between layers. The fractionator's performance is illustrated with DGU-sorted samples of single-walled carbon nanotubes. PMID:25325436

Kadria-Vili, Yara; Canning, Griffin; Bachilo, Sergei M; Weisman, R Bruce

2014-11-18

158

A high-precision mechanical absolute-rotation sensor  

E-print Network

We have developed a mechanical absolute-rotation sensor capable of resolving ground rotation angle of less than 1 nrad$/\\sqrt{\\text{Hz}}$ above $30$ mHz and 0.2 nrad$/\\sqrt{\\text{Hz}}$ above $100$ mHz about a single horizontal axis. The device consists of a meter-scale beam balance, suspended by a pair of flexures, with a resonance frequency of 10.8 mHz. The center of mass is located 3 $\\mu$m above the pivot, giving an excellent horizontal displacement rejection of better than $3\\times10^{-5}$ rad/m. The angle of the beam is read out optically using a high-sensitivity autocollimator. We have also built a tiltmeter with better than 1 nrad$/\\sqrt{\\text{Hz}}$ sensitivity above 30 mHz. Co-located measurements using the two instruments allowed us to distinguish between background rotation signal at low frequencies and intrinsic instrument noise. The rotation sensor is useful for rotational seismology and for rejecting background rotation signal from seismometers in experiments demanding high levels of seismic isol...

Venkateswara, Krishna; Turner, Matthew D; Arp, Trevor; Gundlach, Jens H

2014-01-01

159

A high-precision mechanical absolute-rotation sensor.  

PubMed

We have developed a mechanical absolute-rotation sensor capable of resolving ground rotation angle of less than 1 nrad/?Hz above 30 mHz and 0.2 nrad/?Hz above 100 mHz about a single horizontal axis. The device consists of a meter-scale beam balance, suspended by a pair of flexures, with a resonance frequency of 10.8 mHz. The center of mass is located 3 ?m above the pivot, giving an excellent horizontal displacement rejection of better than 3 × 10(-5) rad/m. The angle of the beam is read out optically using a high-sensitivity autocollimator. We have also built a tiltmeter with better than 1 nrad/?Hz sensitivity above 30 mHz. Co-located measurements using the two instruments allowed us to distinguish between background rotation signal at low frequencies and intrinsic instrument noise. The rotation sensor is useful for rotational seismology and for rejecting background rotation signal from seismometers in experiments demanding high levels of seismic isolation, such as Advanced Laser Interferometer Gravitational-wave Observatory. PMID:24517804

Venkateswara, Krishna; Hagedorn, Charles A; Turner, Matthew D; Arp, Trevor; Gundlach, Jens H

2014-01-01

160

Conditional DNA repair mutants enable highly precise genome engineering.  

PubMed

Oligonucleotide-mediated multiplex genome engineering is an important tool for bacterial genome editing. The efficient application of this technique requires the inactivation of the endogenous methyl-directed mismatch repair system that in turn leads to a drastically elevated genomic mutation rate and the consequent accumulation of undesired off-target mutations. Here, we present a novel strategy for mismatch repair evasion using temperature-sensitive DNA repair mutants and temporal inactivation of the mismatch repair protein complex in Escherichia coli. Our method relies on the transient suppression of DNA repair during mismatch carrying oligonucleotide integration. Using temperature-sensitive control of methyl-directed mismatch repair protein activity during multiplex genome engineering, we reduced the number of off-target mutations by 85%, concurrently maintaining highly efficient and unbiased allelic replacement. PMID:24500200

Nyerges, Ákos; Csorg?, Bálint; Nagy, István; Latinovics, Dóra; Szamecz, Béla; Pósfai, György; Pál, Csaba

2014-04-01

161

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

162

High Precision $J/?$ and $?$-production data and the Nuclear Glue  

E-print Network

We use the high statistics E-772 data on the nuclear dependence of the production of quarkonia $(J/\\psi$ and $\\Upsilon)$ and dimuons at large transverse momentum $(p_T)$ in $p$-$A$ collisions to get information about the gluonic EMC effect. We find a satisfactory quantitative agreement of the theoretical predictions with the data although none of the models of the EMC effect we consider could account for the entire data. Since all the qualitative features are understood none the less in terms of perturbative QCD with nuclear dependent parton densities, our results suggest that these data can now be used for a better determination of the nuclear parton densities. Our conslusions are shown to be insensitive to the hadronisation mechanism for the quarkonia.

R. V. Gavai; R. M. Godbole

1994-02-24

163

A study of the high-precision displacement laser probe  

NASA Astrophysics Data System (ADS)

On the basis of the measuring principle of the dynamic active optical confocal probe based on time difference measurement that has a reference path, a dynamic active optical confocal probe based on time difference measurement but has no reference path is developed. In this paper, the working principle of this optical confocal probe is dissertated. A large-scale integrated measuring system is designed to simplify the structure of the probe and to enhance the stability of the probe. Single-chip microcomputer system with a high-speed ADC is selected in the measurement and control system of the probe. At the end of the paper, experiments on the performance of the optical confocal probe based on time difference measurement with no reference path are carried out. Experiment results show that the probe has a measuring resolution of 0.05?m, a measuring range of 0.2mm and a linearity of 0.4?m.

Fan, Yuming; Zhang, Guoxiong

2006-06-01

164

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

165

Conditional DNA repair mutants enable highly precise genome engineering  

PubMed Central

Oligonucleotide-mediated multiplex genome engineering is an important tool for bacterial genome editing. The efficient application of this technique requires the inactivation of the endogenous methyl-directed mismatch repair system that in turn leads to a drastically elevated genomic mutation rate and the consequent accumulation of undesired off-target mutations. Here, we present a novel strategy for mismatch repair evasion using temperature-sensitive DNA repair mutants and temporal inactivation of the mismatch repair protein complex in Escherichia coli. Our method relies on the transient suppression of DNA repair during mismatch carrying oligonucleotide integration. Using temperature-sensitive control of methyl-directed mismatch repair protein activity during multiplex genome engineering, we reduced the number of off-target mutations by 85%, concurrently maintaining highly efficient and unbiased allelic replacement. PMID:24500200

Nyerges, Akos; Csorgo, Balint; Nagy, Istvan; Latinovics, Dora; Szamecz, Bela; Posfai, Gyorgy; Pal, Csaba

2014-01-01

166

Development of a facility for high-precision irradiation of cells with carbon ions  

SciTech Connect

Purpose: Compared to photons, using particle radiation in radiotherapy reduces the dose and irradiated volume of normal tissues, potentially reducing side effects. The biological effect of dose deposited by particles such as carbon ions, however, differs from that of dose deposited by photons. The inaccuracy in models to estimate the biological effects of particle radiation remains the most important source of uncertainties in particle therapy. Improving this requires high-precision studies on biological effects of particle radiation. Therefore, the authors aimed to develop a facility for reproducible and high-precision carbon-ion irradiation of cells in culture. The combined dose nonuniformity in the lateral and longitudinal direction should not exceed {+-}1.5%. Dose to the cells from particles than other carbon ions should not exceed 5%. Methods: A uniform lateral dose distribution was realized using a single scatter foil and quadrupole magnets. A modulator wheel was used to create a uniform longitudinal dose distribution. The choice of beam energy and the optimal design of these components was determined using GEANT4 and SRIM Monte Carlo simulations. Verification of the uniformity of the dose distribution was performed using a scintillating screen (lateral) and a water phantom (longitudinal). The reproducibility of dose delivery between experiments was assessed by repeated measurements of the spatial dose distribution. Moreover, the reproducibility of dose-response measurements was tested by measuring the survival of irradiated HEK293 cells in three independent experiments. Results: The relative contribution of dose from nuclear reaction fragments to the sample was found to be <5% when using 90 MeV/u carbon ions. This energy still allows accurate dosimetry conforming to the IAEA Report TRS-398, facilitating comparison to dose-effect data obtained with other radiation qualities. A 1.3 mm long spread-out Bragg peak with a diameter of 30 mm was created, allowing the irradiation of cell samples with the specified accuracy. Measurements of the transverse and longitudinal dose distribution showed that the dose variation over the sample volume was {+-}0.8% and {+-}0.7% in the lateral and longitudinal directions, respectively. The track-averaged LET of 132{+-}10 keV/{mu}m and dose-averaged LET of 189{+-}15 keV/{mu}m at the position of the sample were obtained from a GEANT4 simulation, which was validated experimentally. Three separately measured cell-survival curves yielded nearly identical results. Conclusions: With the new facility, high-precision carbon-ion irradiations of biological samples can be performed with highly reproducible results.

Goethem, Marc-Jan van; Niemantsverdriet, Maarten; Brandenburg, Sytze; Langendijk, Johannes A.; Coppes, Robert P.; Luijk, Peter van [Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713AV Groningen (Netherlands); Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, P.O. Box 30001, 9700RB Groningen (Netherlands); Kernfysisch Versneller Instituut, University of Groningen, Zernikelaan 25, 9747AA Groningen (Netherlands); Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, P.O. Box 30001, 9700RB Groningen (Netherlands); Department of Cell Biology, Section of Radiation and Stress Cell Biology, University Medical Center Groningen, University of Groningen, A. Deusinglaan 1, 9713AV Groningen (Netherlands); Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, P.O. Box 30001, 9700RB Groningen (Netherlands)

2011-01-15

167

High-precision pointing and attitude estimation and control algorithms for hardware-constrained spacecraft  

E-print Network

The overarching objective of this thesis is to develop algorithms for high-precision pointing and attitude estimation and control on hardware-constrained spacecraft. This includes small spacecraft, where tight mass, volume, ...

Pong, Christopher Masaru

2014-01-01

168

High-precision osmium isotopes in enstatite and Rumuruti David van Acken a,b,  

E-print Network

High-precision osmium isotopes in enstatite and Rumuruti chondrites David van Acken a,b, , Alan D heterogeneity across the region of chondrite formation. Osmium is an ideal tracer because of its multiple

Weston, Ken

169

High-precision nucleon-nucleon interactions with Brown-Rho scaling medium modifications.  

E-print Network

?? Today, the foundation for most theoretical calculations of nuclear properties across the periodic table is one of the several high-precision nonrelativistic nucleon-nucleon potential models… (more)

Holt, Jeremy William

2010-01-01

170

Isotope-ratio-monitoring gas chromatography methods for high-precision isotopic analysis of nanomole  

E-print Network

Isotope-ratio-monitoring gas chromatography methods for high-precision isotopic analysis and a commercially available continuous-flow, gas chromatography interface (the Finnigan Gas Bench II). This work

Bebout, Gray E.

171

High-precision position control of a heavy-lift manipulator in a dynamic environment  

E-print Network

This thesis considers the control of a heavy-lift serial manipulator operating on the deck of a large ocean vessel. This application presents a unique challenge for high- precision control because the system must contend ...

Garretson, Justin R. (Justin Richard)

2005-01-01

172

High Resolution Airborne Digital Imagery for Precision Agriculture  

NASA Technical Reports Server (NTRS)

The Environmental Research Aircraft and Sensor Technology (ERAST) program is a NASA initiative that seeks to demonstrate the application of cost-effective aircraft and sensor technology to private commercial ventures. In 1997-98, a series of flight-demonstrations and image acquisition efforts were conducted over the Hawaiian Islands using a remotely-piloted solar- powered platform (Pathfinder) and a fixed-wing piloted aircraft (Navajo) equipped with a Kodak DCS450 CIR (color infrared) digital camera. As an ERAST Science Team Member, I defined a set of flight lines over the largest coffee plantation in Hawaii: the Kauai Coffee Company's 4,000 acre Koloa Estate. Past studies have demonstrated the applications of airborne digital imaging to agricultural management. Few studies have examined the usefulness of high resolution airborne multispectral imagery with 10 cm pixel sizes. The Kodak digital camera integrated with ERAST's Airborne Real Time Imaging System (ARTIS) which generated multiband CCD images consisting of 6 x 106 pixel elements. At the designated flight altitude of 1,000 feet over the coffee plantation, pixel size was 10 cm. The study involved the analysis of imagery acquired on 5 March 1998 for the detection of anomalous reflectance values and for the definition of spectral signatures as indicators of tree vigor and treatment effectiveness (e.g., drip irrigation; fertilizer application).

Herwitz, Stanley R.

1998-01-01

173

A high precision ultrasonic system for vibration measurements  

NASA Astrophysics Data System (ADS)

A microcomputer-aided ultrasonic system that can be used to measure the vibratory displacements of an object is presented. A pair of low cost 40-kHz ultrasonic transducers is used to transmit ultrasound toward an object and receive the ultrasound reflected from the object. The relative motion of the object modulates the phase angle difference between the transmitted and received ultrasound signals. A single-chip microcomputer-based phase detector was designed to record and analyze the phase shift information which is then sent to a PC-AT microcomputer for processing. We have developed an ingenious method to reconstruct the relative motion of an object from the acquired data of the phase difference changes. A digital plotter based experiment was also designed for testing the performance of the whole system. The measured accuracy of the system in the reported experiments is within +/- 0.4 mm and the theoretical maximal measurable speed of the object is 89.6 cm/s. The main advantages of this ultrasonic vibration measurement system are high resolution, low cost, noncontact measurement, and easy installation.

Young, M. S.; Li, Y. C.

1992-11-01

174

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

175

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

176

High Precision Pulsar Timing: Effects of ISM Correction Schemes  

NASA Astrophysics Data System (ADS)

Pulsar timing arrays are one of the leading methods in the search for gravitational waves (GWs). However a significant issue facing this method is the effect of the interstellar medium (ISM). There are multiple methodologies being used to correct for these effects but their efficacy has not been carefully studied. We conducted an initial study of biases induced by correcting for the interstellar medium. We simulated times of arrival (TOAs) with white noise and added ISM delays. We measure the ISM effects as is done with normal data, and created a model of these effects using polynomial fitting. This modeling method is most commonly used in the European Pulsar Timing Array. We then remove these measured ISM effects and compare final and initial TOAs. Ideally they should be the same; however, the differences between the 'corrected' TOAs and original TOAs reveal the weaknesses of this method. In preliminary results we concluded that the higher order polynomials do a better job, yet there is a limit as to how high an order one can use. We also found no significant systematic parameter bias induced by using this method. However, it is clear that certain parameters are more affected by this process of correction. The parameters most affected were the frequency and frequency derivative of the pulsar, but biases in these parameters are not important because the power due to them gets removed in the standard timing analysis. We are continuing this research by comparing and contrasting ISM correction schemes, as well as studying the actual behavior of the ISM in more detail. This research is supported by an NSF-PIRE and an NSF-AST grant.

Kunert, Willie; Verbiest, J. P. W.; Shannon, R.; Stinebring, D.

2012-01-01

177

Effect of inhomogeneities on high precision measurements of cosmological distances  

E-print Network

We study exact relativistic effects of inhomogeneities on distance measures, focusing on the distance modulus, in a Swiss-cheese model of the universe with $\\Lambda$CDM background dynamics, and where the `holes' are non-symmetric structures described by the Szekeres metric. The Szekeres exact solution of Einstein's equations, which is inhomogeneous and anisotropic, allows us to capture potentially relevant effects on light propagation due to nontrivial evolution of structures. Unlike Swiss-cheese model studies with spherically symmetric holes, we find a net shift in the distance modulus $\\mu$ to distant sources even when we average over many lines of sight with randomized hole orientations and impact parameters. The light also need not propagate strictly through underdense regions to result in an overall bias, which is an accumulated effect associated with the evolution of the anisotropic holes. We find the average shift $\\langle\\Delta\\mu\\rangle$ relative to a pure $\\Lambda$CDM model to increase with redshift in general, and the spread $\\sigma_{\\Delta\\mu}$ of the distribution to increase, as well. For sources at high redshifts, the bias can be as large as $\\langle\\Delta\\mu\\rangle=-0.0337$ mag with $\\sigma_{\\Delta\\mu}=0.0093$ mag, corresponding to a fractional error on the source luminosity distance of 1.56%, which in principle alters the Hubble diagram and our inference of cosmological parameters. Corrections to $\\mu$ of this size, while small compared to the typical uncertainty of a single type Ia supernova, could translate with binning to an important systematic effect due to inhomogeneities that exceeds statistical errors. Indeed, with the statistical improvements expected in upcoming surveys, systematic biases arising from nonlinear relativistic effects such as those studied here will become a limiting factor to consider in constraining cosmological parameters.

Austin Peel; M. A. Troxel; Mustapha Ishak

2014-08-19

178

Assessing the precision of strain measurements using electron backscatter diffraction--part 2: experimental demonstration.  

PubMed

The residual impression after performing a microhardness indent in silicon has been mapped with high resolution EBSD to reveal residual elastic strain and lattice rotation fields. Mapping of the same area has been performed with variable pattern binning and exposure times to reveal the qualitative and quantitative differences resulting from reducing the pattern size and exposure time. Two dimension 'image' plots of these fields indicate that qualitative assessment of the shape and size of the fields can be performed with as much as 4×4 binning. However, quantitative assessment using line scans reveals that the smoothest profile can be obtained using minimal pattern binning and long exposure times. To compare and contrast with these experimental maps, finite element analysis has been performed using a continuum damage-plasticity material law which has been independently calibrated to Si [9]. The constitutive law incorporates isotropic hardening in compression, and isotropic hardening and damage in tension. To accurately capture the localised damage which develops during indentation via the nucleation and propagation of cracks around the indentation site cohesive elements were assigned along the interfaces between the planes which experience the maximum traction. The residual strain state around the indenter and the size of the cracks agree very well with the experimentally measured value. PMID:24034981

Britton, T B; Jiang, J; Clough, R; Tarleton, E; Kirkland, A I; Wilkinson, A J

2013-12-01

179

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

180

Design of high precision motor driving system for circular scanning ultrasonic endoscopic imaging equipment  

NASA Astrophysics Data System (ADS)

This paper describes the development of a motor driving system for circular scanning ultrasonic endoscopic imaging equipment. It was designed to guarantee the motor rotating at a relatively constant speed in load fluctuation conditions, which result from the bending and twisting of the flexible shaft which connects the probe to the motor. A hardware feedback circuit based on Frequency-To-Voltage Converter LM331 and Step-Down Voltage Regulator LM2576-ADJ was designed to ensure steady rotation of motor in load fluctuation conditions, and a D/A module offered by MCU was used to regulate the real-time rotary speed. The feedback response cycle is about 20 ?s according to theoretical analysis. Experimental results show that the maximum error is +/-1 r/min under the normal running environment (300 ~1500 r/min) and load fluctuation conditions, which means the average instability is reduced to 0.11% as compared with that of the motor drive simply based on MCU which is 0.94%. Both theoretical analysis and experimental results indicate that the motor driving system has high accuracy, fast response, excellent reliability and good versatility and portability, and can precisely guarantee the smooth movement of load-changing PMW (Pulse Width Modulation) motor, so as to ensure the imaging quality, and can effectively improve the efficiency and accuracy of the diagnosis.

Deng, Haoran; Bai, Baoping; Chen, Xiaodong; Zhao, Qiang; Li, Yanan; Wang, Yi; Yu, Daoyin

2013-12-01

181

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. PMID:20813570

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

2010-01-01

182

GNSS receiver clock modeling when using high-precision oscillators and its impact on PPP  

NASA Astrophysics Data System (ADS)

Processing data from Global Navigation Satellite Systems (GNSS) always requires time synchronization between transmitter and receiver clocks. Due to the limited stability of the receiver’s internal oscillator, the offset of the receiver clock with respect to the system time has to be estimated for every observation epoch or eliminated by processing differences between simultaneous observations. If, in contrast, the internal oscillator of the receiver is replaced by a stable atomic clock one can try to model the receiver clock offset, instead of estimating it on an epoch-by-epoch basis. In view of the progress made in the field of high-precision frequency standards we will investigate the technical requirements for GNSS receiver clock modeling at the carrier phase level and analyze its impact on the precision of the position estimates.If we want to take advantage of the frequency stability provided by a high-performance oscillator in combination with a GNSS receiver we have to ensure that the signal delays inside the receiver hardware remain constant. Therefore, we have analyzed the relative receiver clock offsets for a number of GNSS receivers that derive their frequency reference from a common oscillator. Based on experimental data of an exemplary pair of geodetic receivers we show that the noise from variations of the hardware delays in the receiver electronics does not exceed the receiver clock noise (5 ps RMS) when all environmental effects are carefully controlled.By analyzing the elements of the parameter covariance matrix for a simple case of point positioning, the impact of GNSS receiver clock modeling on kinematic and static solutions is studied. Furthermore, we demonstrate the suitability of a single quadratic polynomial to model a receiver clock that is locked to the frequency of an active hydrogen maser for periods up to 24 h. Based on simulated and real GNSS data it is shown that receiver clock modeling improves the RMS of the height component of a kinematic Precise Point Positioning (PPP) by up to 70%, whereas for the static case the gain is almost negligible.

Weinbach, U.; Schön, S.

2011-01-01

183

Controller design and implementation for a 6-degree-of-freedom magnetically levitated positioner with high precision.  

E-print Network

??This thesis presents the controller design and implementation of a high-precision 6-degree-of-freedom (6-DOF) magnetically levitated (maglev) positioner. This high-precision positioning system consists of a novel… (more)

Yu, Ho

2005-01-01

184

HIGH PRECISION K-SHELL PHOTOABSORPTION CROSS SECTIONS FOR ATOMIC OXYGEN: EXPERIMENT AND THEORY  

SciTech Connect

Photoabsorption of atomic oxygen in the energy region below the 1s {sup -1} threshold in X-ray spectroscopy from Chandra and XMM-Newton is observed in a variety of X-ray binary spectra. Photoabsorption cross sections determined from an R-matrix method with pseudo-states and new, high precision measurements from the Advanced Light Source (ALS) are presented. High-resolution spectroscopy with E/{Delta}E Almost-Equal-To 4250 {+-} 400 was obtained for photon energies from 520 eV to 555 eV at an energy resolution of 124 {+-} 12 meV FWHM. K-shell photoabsorption cross section measurements were made with a re-analysis of previous experimental data on atomic oxygen at the ALS. Natural line widths {Gamma} are extracted for the 1s {sup -1}2s {sup 2}2p {sup 4}({sup 4} P)np {sup 3} P Degree-Sign and 1s {sup -1}2s {sup 2}2p {sup 4}({sup 2} P)np {sup 3} P Degree-Sign Rydberg resonances series and compared with theoretical predictions. Accurate cross sections and line widths are obtained for applications in X-ray astronomy. Excellent agreement between theory and the ALS measurements is shown which will have profound implications for the modeling of X-ray spectra and spectral diagnostics.

McLaughlin, B. M. [Centre for Theoretical Atomic, Molecular and Optical Physics (CTAMOP), School of Mathematics and Physics, Queen's University Belfast, Belfast BT7 1NN (United Kingdom); Ballance, C. P. [Department of Physics, 206 Allison Laboratory, Auburn University, Auburn, AL 36849-5311 (United States); Bowen, K. P.; Gardenghi, D. J.; Stolte, W. C., E-mail: b.mclaughlin@qub.ac.uk, E-mail: ballance@physics.auburn.edu, E-mail: bowenk4@gmail.com, E-mail: dgardenghi@gmail.com, E-mail: wcstolte@lbl.gov [Department of Chemistry, University of Nevada, Las Vegas, NV 89154-4003 (United States)

2013-07-01

185

Precise physical models of protein-DNA interaction from high-throughput data  

PubMed Central

A cell's ability to regulate gene transcription depends in large part on the energy with which transcription factors (TFs) bind their DNA regulatory sites. Obtaining accurate models of this binding energy is therefore an important goal for quantitative biology. In this article, we present a principled likelihood-based approach for inferring physical models of TF–DNA binding energy from the data produced by modern high-throughput binding assays. Central to our analysis is the ability to assess the relative likelihood of different model parameters given experimental observations. We take a unique approach to this problem and show how to compute likelihood without any explicit assumptions about the noise that inevitably corrupts such measurements. Sampling possible choices for model parameters according to this likelihood function, we can then make probabilistic predictions for the identities of binding sites and their physical binding energies. Applying this procedure to previously published data on the Saccharomyces cerevisiae TF Abf1p, we find models of TF binding whose parameters are determined with remarkable precision. Evidence for the accuracy of these models is provided by an astonishing level of phylogenetic conservation in the predicted energies of putative binding sites. Results from in vivo and in vitro experiments also provide highly consistent characterizations of Abf1p, a result that contrasts with a previous analysis of the same data. PMID:17197415

Kinney, Justin B.; Tkacik, Gasper; Callan, Curtis G.

2007-01-01

186

High Precision {\\it K}-Shell Photoabsorption Cross Sections for Atomic Oxygen: Experiment and Theory  

E-print Network

Photoabsorption of atomic oxygen in the energy region below the $\\rm 1s^{-1}$ threshold in x-ray spectroscopy from {\\it Chandra} and {\\it XMM-Newton} is observed in a variety of x-ray binary spectra. Photoabsorption cross sections determined from an R-matrix method with pseudo-states (RMPS) and new, high precision measurements from the Advanced Light Source (ALS) are presented. High-resolution spectroscopy with E/$\\Delta$E $\\approx$ 4,250 $\\pm$ 400 was obtained for photon energies from 520 eV to 555 eV at an energy resolution of 124 $\\pm$ 12 meV FWHM. {\\it K}-shell photoabsorption cross-section measurements were made with a re-analysis of previous experimental data on atomic oxygen at the ALS. Natural linewidths $\\Gamma$ are extracted for the $\\rm 1s^{-1}2s^22p^4 (^4P)np ^3P^{\\circ}$ and $\\rm 1s^{-1}2s^22p^4(^2P)np ~^3P^{\\circ}$ Rydberg resonances series and compared with theoretical predictions. Accurate cross sections and linewidths are obtained for applications in x-ray astronomy. Excellent agreement betwe...

McLaughlin, B M; Bowen, K P; Gardenghi, D J; Stolte, W C

2013-01-01

187

High-precision thickness setting models for titanium alloy plate cold rolling without tension  

NASA Astrophysics Data System (ADS)

Due to its highly favorable physical and chemical properties, titanium and titanium alloy are widely used in a variety of industries. Because of the low output of a single batch, plate cold rolling without tension is the most common rolling production method for titanium alloy. This method is lack of on-line thickness closed-loop control, with carefully thickness setting models for precision. A set of high-precision thickness setting models are proposed to suit the production method. Because of frequent variations in rolling specification, a model structural for the combination of analytical models and statistical models is adopted to replace the traditional self-learning method. The deformation resistance and friction factor, the primary factors which affect model precision, are considered as the objectives of statistical modeling. Firstly, the coefficient fitting of deformation resistance analytical model based on over-determined equations set is adopted. Additionally, a support vector machine(SVM) is applied to the modeling of the deformation resistance and friction factor. The setting models are applied to a 1450 plate-coiling mill for titanium alloy plate rolling, and then thickness precision is found consistently to be within 3%, exceeding the precision of traditional setting models with a self-learning method based on a large number of stable rolling data. Excellent application performance is obtained. The proposed research provides a set of high-precision thickness setting models which are well adapted to the characteristics of titanium alloy plate cold rolling without tension.

Wang, Xiaochen; Yang, Quan; He, Fei; Sun, Youzhao; Xiao, Huifang

2014-10-01

188

High-precision B (E2) measurements of semi-magic Ni58,60,62,64 by Coulomb excitation  

NASA Astrophysics Data System (ADS)

High-precision reduced electric-quadrupole transition probabilities B (E2;01+?21+) have been measured from single-step Coulomb excitation of semi-magic Ni58,60,62,64 (Z=28) beams at 1.8 MeV per nucleon on a natural carbon target. The energy loss of the nickel beams through the carbon target were directly measured with a zero-degree Bragg detector and the absolute B (E2) values were normalized by Rutherford scattering. The B (E2) values disagree with recent lifetime studies that employed the Doppler-shift attenuation method. The present high-precision B (E2) values reveal an asymmetry about Ni62, midshell between N =28 and 40, with larger values towards Ni56 (Z =N=28). The experimental B (E2) values are compared with shell-model calculations in the full pf model space and the results indicate a soft Ni56 core.

Allmond, J. M.; Brown, B. A.; Stuchbery, A. E.; Galindo-Uribarri, A.; Padilla-Rodal, E.; Radford, D. C.; Batchelder, J. C.; Howard, M. E.; Liang, J. F.; Manning, B.; Varner, R. L.; Yu, C.-H.

2014-09-01

189

Natural Vs. Precise Concise Languages for Human Operation of Computers: Research Issues and Experimental Approaches  

Microsoft Academic Search

This paper raises concerns that natural language front ends for computer systems can limit a researcher's scope of thinking, yield inappropriately complex systems, and exaggerate public fear of computers. Alternative modes of computer use are suggested and the role of psychologically oriented controlled experimentation is emphasized. Research methods and recent experimental results are briefly reviewed.

Ben Shneiderman

1980-01-01

190

MATS and LaSpec: High-precision experiments using ion traps and lasers at FAIR  

NASA Astrophysics Data System (ADS)

Nuclear ground state properties including mass, charge radii, spins and moments can be determined by applying atomic physics techniques such as Penning-trap based mass spectrometry and laser spectroscopy. The MATS and LaSpec setups at the low-energy beamline at FAIR will allow us to extend the knowledge of these properties further into the region far from stability. The mass and its inherent connection with the nuclear binding energy is a fundamental property of a nuclide, a unique “fingerprint”. Thus, precise mass values are important for a variety of applications, ranging from nuclear-structure studies like the investigation of shell closures and the onset of deformation, tests of nuclear mass models and mass formulas, to tests of the weak interaction and of the Standard Model. The required relative accuracy ranges from 10-5 to below 10-8 for radionuclides, which most often have half-lives well below 1 s. Substantial progress in Penning trap mass spectrometry has made this method a prime choice for precision measurements on rare isotopes. The technique has the potential to provide high accuracy and sensitivity even for very short-lived nuclides. Furthermore, ion traps can be used for precision decay studies and offer advantages over existing methods. With MATS (Precision Measurements of very short-lived nuclei using an A_dvanced Trapping System for highly-charged ions) at FAIR we aim to apply several techniques to very short-lived radionuclides: High-accuracy mass measurements, in-trap conversion electron and alpha spectroscopy, and trap-assisted spectroscopy. The experimental setup of MATS is a unique combination of an electron beam ion trap for charge breeding, ion traps for beam preparation, and a high-precision Penning trap system for mass measurements and decay studies. For the mass measurements, MATS offers both a high accuracy and a high sensitivity. A relative mass uncertainty of 10-9 can be reached by employing highly-charged ions and a non-destructive Fourier-Transform Ion-Cyclotron-Resonance (FT-ICR) detection technique on single stored ions. This accuracy limit is important for fundamental interaction tests, but also allows for the study of the fine structure of the nuclear mass surface with unprecedented accuracy, whenever required. The use of the FT-ICR technique provides true single ion sensitivity. This is essential to access isotopes that are produced with minimum rates which are very often the most interesting ones. Instead of pushing for highest accuracy, the high charge state of the ions can also be used to reduce the storage time of the ions, hence making measurements on even shorter-lived isotopes possible. Decay studies in ion traps will become possible with MATS. Novel spectroscopic tools for in-trap high-resolution conversion-electron and charged-particle spectroscopy from carrier-free sources will be developed, aiming e.g. at the measurements of quadrupole moments and E0 strengths. With the possibility of both high-accuracy mass measurements of the shortest-lived isotopes and decay studies, the high sensitivity and accuracy potential of MATS is ideally suited for the study of very exotic nuclides that will only be produced at the FAIR facility.Laser spectroscopy of radioactive isotopes and isomers is an efficient and model-independent approach for the determination of nuclear ground and isomeric state properties. Hyperfine structures and isotope shifts in electronic transitions exhibit readily accessible information on the nuclear spin, magnetic dipole and electric quadrupole moments as well as root-mean-square charge radii. The dependencies of the hyperfine splitting and isotope shift on the nuclear moments and mean square nuclear charge radii are well known and the theoretical framework for the extraction of nuclear parameters is well established. These extracted parameters provide fundamental information on the structure of nuclei at the limits of stability. Vital information on both bulk and valence nuclear properties are derived and an exceptional sensitivity to changes in nuclear def

Rodríguez, D.; Blaum, K.; Nörtershäuser, W.; Ahammed, M.; Algora, A.; Audi, G.; Äystö, J.; Beck, D.; Bender, M.; Billowes, J.; Block, M.; Böhm, C.; Bollen, G.; Brodeur, M.; Brunner, T.; Bushaw, B. A.; Cakirli, R. B.; Campbell, P.; Cano-Ott, D.; Cortés, G.; Crespo López-Urrutia, J. R.; Das, P.; Dax, A.; de, A.; Delheij, P.; Dickel, T.; Dilling, J.; Eberhardt, K.; Eliseev, S.; Ettenauer, S.; Flanagan, K. T.; Ferrer, R.; García-Ramos, J.-E.; Gartzke, E.; Geissel, H.; George, S.; Geppert, C.; Gómez-Hornillos, M. B.; Gusev, Y.; Habs, D.; Heenen, P.-H.; Heinz, S.; Herfurth, F.; Herlert, A.; Hobein, M.; Huber, G.; Huyse, M.; Jesch, C.; Jokinen, A.; Kester, O.; Ketelaer, J.; Kolhinen, V.; Koudriavtsev, I.; Kowalska, M.; Krämer, J.; Kreim, S.; Krieger, A.; Kühl, T.; Lallena, A. M.; Lapierre, A.; Le Blanc, F.; Litvinov, Y. A.; Lunney, D.; Martínez, T.; Marx, G.; Matos, M.; Minaya-Ramirez, E.; Moore, I.; Nagy, S.; Naimi, S.; Neidherr, D.; Nesterenko, D.; Neyens, G.; Novikov, Y. N.; Petrick, M.; Plaß, W. R.; Popov, A.; Quint, W.; Ray, A.; Reinhard, P.-G.; Repp, J.; Roux, C.; Rubio, B.; Sánchez, R.; Schabinger, B.; Scheidenberger, C.; Schneider, D.; Schuch, R.; Schwarz, S.; Schweikhard, L.; Seliverstov, M.; Solders, A.; Suhonen, M.; Szerypo, J.; Taín, J. L.; Thirolf, P. G.; Ullrich, J.; van Duppen, P.; Vasiliev, A.; Vorobjev, G.; Weber, C.; Wendt, K.; Winkler, M.; Yordanov, D.; Ziegler, F.

2010-05-01

191

High precision X-ray stereo for automated 3D CAD-based inspection  

Microsoft Academic Search

An important challenge in industrial metrology is to provide rapid measurement of critical 3D internal object geometry for either inspecting high volume parts or controlling a machining process. Existing metrological techniques are typically too slow to meet this need or can not measure small features with high precision. In this paper, we present a new method that achieves fast, accurate,

J. Alison Noble; Rajiv Gupta; Joe Mundy; Andrea Schmitz; Richard I. Hartley

1998-01-01

192

Method for high precision local positioning radar using an ultra wideband technique  

Microsoft Academic Search

In this paper, a novel approach for a high precision local positioning radar using an ultra wideband technique is presented. The concept is based on the standard FMCW (frequency modulated continuous wave) radar principle combined with short pulses to fulfill the emission limits given by the official regulatory authorities. With this concept, a high accuracy in dense multipath indoor environments

Benjamin Waldmann; Robert Weigel; Peter Gulden

2008-01-01

193

High-Precision Selective Deposition of Catalyst for Facile Localized Growth of  

E-print Network

High-Precision Selective Deposition of Catalyst for Facile Localized Growth of Single Walled Carbon of the proposed technique comparing to conventional M/NEMS technique (e.g. lift-offf) is as followings. Firstly, the resolution can be expected to be very high, and a SWNT pattern with the line-wide of 50 nm can be easily

Maruyama, Shigeo

194

A modified highly precise direct integration method for a class of linear time-varying systems  

NASA Astrophysics Data System (ADS)

It is always a bottleneck to design an effective algorithm for linear time-varying systems in engineering applications. For a class of systems, whose coefficients matrix is based on time-varying polynomial, a modified highly precise direct integration (VHPD-T method) was presented. Through introducing new variables and expanding dimensions, the system can be transformed into a time-invariant system, in which the transfer matrix can be computed for once and used forever with a highly precise direct integration method. The method attains higher precision than the common methods (e.g. RK4 and power series) and high efficiency in computation. Some numerical examples demonstrate the validity and efficiency of the method proposed.

Liu, XiaoMei; Zhou, Gang; Zhu, Shuai; Wang, YongHong; Sun, WeiRong; Weng, ShiLie

2014-07-01

195

High-precision two-way optic-fiber time transfer using an improved time code  

NASA Astrophysics Data System (ADS)

We present a novel high-precision two-way optic-fiber time transfer scheme. The Inter-Range Instrumentation Group (IRIG-B) time code is modified by increasing bit rate and defining new fields. The modified time code can be transmitted directly using commercial optical transceivers and is able to efficiently suppress the effect of the Rayleigh backscattering in the optical fiber. A dedicated codec (encoder and decoder) with low delay fluctuation is developed. The synchronization issue is addressed by adopting a mask technique and combinational logic circuit. Its delay fluctuation is less than 27 ps in terms of the standard deviation. The two-way optic-fiber time transfer using the improved codec scheme is verified experimentally over 2 m to100 km fiber links. The results show that the stability over 100 km fiber link is always less than 35 ps with the minimum value of about 2 ps at the averaging time around 1000 s. The uncertainty of time difference induced by the chromatic dispersion over 100 km is less than 22 ps.

Wu, Guiling; Hu, Liang; Zhang, Hao; Chen, Jianping

2014-11-01

196

Laser ablation and high precision patterning of biomaterials and intraocular lenses  

NASA Astrophysics Data System (ADS)

The use of intraocular lenses (IOL) is the most promising method for restoring excellent vision in cataract surgery. In addition, multifocal intraocular lenses for good distant and near vision are investigated. Several new materials, techniques and patterns are studied for the formation and etching of intraocular lenses in order to improve their optical properties and reduce the diffractive aberrations. As pulsed laser ablation is well established as a universal tool for surface processing of organic polymer materials, this study was focused in using laser ablation with short and ultra short laser pulses for surface modification of PMMA and intraocular lenses, instead of using other conventional techniques. The main advantage of using very short laser pulses, e.g. of ns, ps or fs duration, is that heat diffusion into the polymer material is negligible. As a result high precision patterning of the sample, without thermal damage of the surroundings, becomes possible. In this study, laser ablation was performed using commercially available hydrophobic acrylic IOLs, hydrophilic acrylic IOLs, and PMMA IOLs, with various diopters. We investigated the ablation efficiency and the phenomenology of the etched patterns by testing the ablation rate, versus laser energy fluence, at several wavelengths and the surface modification with atomic force microscopy (AFM), or scanning electron microscopy (SEM). The irradiated polymers have different optical properties, at the applied wavelengths, and therefore, present different ablation behaviour and morphology of the laser ablated crater walls and surrounding surfaces. The experimental results, some theoretical assumptions for mathematical modeling of the relevant ablation mechanisms are discussed.

Serafetinides, A. A.; Spyratou, E.; Makropoulou, M.

2010-10-01

197

Gradient-based high precision alignment of cryo-electron subtomograms  

PubMed Central

Whole cell cryo-electron tomography emerges as an important component for structural system biology approaches. It allows the localization and structural characterization of macromolecular complexes in near living conditions. However, the method is hampered by low resolution, missing data and low signal-to-noise ratio (SNR). To overcome some of these difficulties one can align and average a large set of subtomograms. Existing alignment methods are mostly based on an exhaustive scanning and sampling of all but discrete relative rotations and translations of one subtomogram with respect to the other. In this paper, we propose a gradient-guided alignment method based on two subtomogram similarity measures. We also propose a stochastic parallel optimization that increases significantly the efficiency for the simultaneous refinement of a set of alignment candidates. Results on simulated data of model complexes and experimental structures of protein complexes show that even for highly distorted subtomograms and with only a small number of very sparsely distributed initial alignment seeds, our method can accurately recover true transformations with a significantly higher precision than scanning based alignment methods. PMID:25068871

Xu, Min; Alber, Frank

2014-01-01

198

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

199

High precision measurement of the proton charge radius: The PRad experiment  

SciTech Connect

The recent high precision measurements of the proton charge radius performed at PSI from muonic hydrogen Lamb shift puzzled the hadronic physics community. A value of 0.8418 ± 0.0007 fm was extracted which is 7? smaller than the previous determinations obtained from electron-proton scattering experiments and based on precision spectroscopy of electronic hydrogen. An additional extraction of the proton charge radius from electron scattering at Mainz is also in good agreement with these 'electronic' determinations. An independent measurement of the proton charge radius from unpolarized elastic ep scattering using a magnetic spectrometer free method was proposed and fully approved at Jefferson Laboratory in June 2012. This novel technique uses the high precision calorimeter HyCal and a windowless hydrogen gas target which makes possible the extraction of the charge radius at very forward angles and thus very low momentum transfer Q{sup 2} up to 10{sup ?4} (GeV/c){sup 2} with an unprecedented sub-percent precision for this type of experiment. In this paper, after a review of the recent progress on the proton charge radius extraction and the new high precision experiment PRad will be presented.

Meziane, Mehdi [Duke University, Durham, NC 27708 (United States); Collaboration: PRad Collaboration

2013-11-07

200

High precision measurement of the proton charge radius: The PRad experiment  

NASA Astrophysics Data System (ADS)

The recent high precision measurements of the proton charge radius performed at PSI from muonic hydrogen Lamb shift puzzled the hadronic physics community. A value of 0.8418 ± 0.0007 fm was extracted which is 7? smaller than the previous determinations obtained from electron-proton scattering experiments and based on precision spectroscopy of electronic hydrogen. An additional extraction of the proton charge radius from electron scattering at Mainz is also in good agreement with these "electronic" determinations. An independent measurement of the proton charge radius from unpolarized elastic ep scattering using a magnetic spectrometer free method was proposed and fully approved at Jefferson Laboratory in June 2012. This novel technique uses the high precision calorimeter HyCal and a windowless hydrogen gas target which makes possible the extraction of the charge radius at very forward angles and thus very low momentum transfer Q2 up to 10-4 (GeV/c)2 with an unprecedented sub-percent precision for this type of experiment. In this paper, after a review of the recent progress on the proton charge radius extraction and the new high precision experiment PRad will be presented.

Meziane, Mehdi; PRad Collaboration

2013-11-01

201

High precision measurement of the proton charge radius: The PRad experiment  

SciTech Connect

The recent high precision measurements of the proton charge radius performed at PSI from muonic hydrogen Lamb shift puzzled the hadronic physics community. A value of 0.8418 {+-} 0.0007 fm was extracted which is 7{sigma} smaller than the previous determinations obtained from electron-proton scattering experiments and based on precision spectroscopy of electronic hydrogen. An additional extraction of the proton charge radius from electron scattering at Mainz is also in good agreement with these "electronic" determinations. An independent measurement of the proton charge radius from unpolarized elastic ep scattering using a magnetic spectrometer free method was proposed and fully approved at Jefferson Laboratory in June 2012. This novel technique uses the high precision calorimeter HyCal and a windowless hydrogen gas target which makes possible the extraction of the charge radius at very forward angles and thus very low momentum transfer Q{sup 2} up to 10{sup -4} (GeV/c){sup 2} with an unprecedented sub-percent precision for this type of experiment. In this paper, after a review of the recent progress on the proton charge radius extraction and the new high precision experiment PRad will be presented.

Meziane, Mehdi [DUKE

2013-11-01

202

A high precision attitude determination and control system for the UYS-1 nanosatellite  

NASA Astrophysics Data System (ADS)

This paper presents the design of a high precision attitude determination and control system for the UYS-1 Ukrainian nanosatellite. Its main task is the 3-axis stabilization with less than 0.5° angle errors, so the satellite may take high precision photos of Earth's surface. To accomplish this task, this system comprises a star tracker and three reaction wheels. To avoid external disturbances and actuators faults, a PD-type and a PID-type robust controllers are simulated and the results are compared to an empirically adjusted PD controller.

Chaurais, J. R.; Ferreira, H. C.; Ishihara, J. Y.; Borges, R. A.; Kulabukhov, A. M.; Larin, V. A.; Belikov, V. V.

203

CHEOPS: a space telescope for ultra-high precision photometry of exoplanet transits  

NASA Astrophysics Data System (ADS)

The CHaracterising ExOPlanet Satellite (CHEOPS) is a joint ESA-Switzerland space mission (expected to launch in 2017) dedicated to search for exoplanet transits by means of ultra-high precision photometry. CHEOPS will provide accurate radii for planets down to Earth size. Targets will mainly come from radial velocity surveys. The CHEOPS instrument is an optical space telescope of 30 cm clear aperture with a single focal plane CCD detector. The tube assembly is passively cooled and thermally controlled to support high precision, low noise photometry. The telescope feeds a re-imaging optic, which supports the straylight suppression concept to achieve the required Signal to Noise.

Fortier, Andrea; Beck, Thomas; Benz, Willy; Broeg, Christopher; Cessa, Virginie; Ehrenreich, David; Thomas, Nicolas

2014-08-01

204

A simple breathing circuit allowing precise control of inspiratory gases for experimental respiratory manipulations  

PubMed Central

Background Respiratory manipulations modulating blood flow and oxygenation levels have become an important component of modern functional MRI applications. Manipulations often consist of temporarily switching inspired fractions of CO2 and O2; and have typically been performed using simple oxygen masks intended for applications in respiratory therapy. However, precise control of inspired gas composition is difficult using this type of mask due to entrainment of room air and resultant dilution of inspired gases. We aimed at developing a gas delivery apparatus allowing improved control over the fractional concentration of inspired gases, to be used in brain fMRI studies. Findings The breathing circuit we have conceived allowed well controlled step changes in FiO2 and FiCO2, at moderate flow rates achievable on standard clinical flow regulators. In a two run test inside the scanner we demonstrate that tightly controlled simple gas switching manipulations can afford good intra-subject reproducibility of induced hyperoxia/hypercapnia responses. Although our approach requires a non-vented mask fitting closely to the subject’s face, the circuit ensures a continuous supply of breathable air even if the supply of medical gases is interrupted, and is easily removable in case of an emergency. The apparatus we propose is also compact and MRI compatible, allowing subject placement in confined spaces such as an MRI scanner for brain examinations. Conclusions We have reported a new approach for the controlled administration of medical gases, and describe an implementation of the breathing circuit that is MRI compatible and uses commercially available parts. The resultant apparatus allows simple, safe and precise manipulations of FiO2 and FiCO2. PMID:24725848

2014-01-01

205

Development of laser-based application system with high precision and speed  

NASA Astrophysics Data System (ADS)

Recently, PCB(Printed Circuit Board) is required more high precision, function and miniaturization for advanced electronics, display, semiconductor and packaging, etc. and this complex PCB needs cutting, repair, trimming and structuring, etc. So, we make complex machine that is possible this all PCB processing and test PCB material processing using developed machine. This machine consists of UV nano-second pulse laser, power controller(self-developments), probe stage for trimming, auto focusing and scanner. The power controller is possible to monitor real-time power and adjust precision laser power. Using various parameters such as laser power, scanning speed, repetition rate and pulsed overlaps can obtain for process result having high precision and speed.

Ryu, Kwang-hyun; Shin, Suk-hoon; Park, Hyeong-chan; Hwang, Tae-sang

2012-03-01

206

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

SciTech Connect

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 the amplitude and frequency of vibrations. Under laboratory conditions, measurement precision of {approx}50 nm was achieved for absolute distances ranging from 0.1 to 0.7 m by use of the first multiple-distance-measurement technique. The second analysis technique has the capability to measure vibration frequencies ranging from 0.1 to 100 Hz with an amplitude as small as a few nanometers without a priori knowledge.

Yang, H.-J.; Deibel, Jason; Nyberg, Sven; Riles, Keith

2005-07-01

207

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

208

High-Precision Selective Deposition of Catalyst for Facile Localized Growth of Single Walled Carbon Nanotubes  

E-print Network

Shiomi1 , Shigeo Maruyama1 1 Department of Mechanical Engineering, The University of Tokyo, Tokyo 113, T. Wu, E. Einarsson, Y. Suzuki, Y. Murakami, J. Shiomi, S. Maruyama, High-Precision Selective. Corresponding Author: Shigeo Maruyama Email: maruyama@photon.t.u-tokyo.ac.jp POSTER SESSION P8 WONTON '09 78

Maruyama, Shigeo

209

A Highly Accurate Stress Measurement System for Producing Precise X-Ray Masks  

Microsoft Academic Search

A new system that measures stress in film deposited on Si wafers has been developed to produce highly accurate X-ray masks. The system consists of very rigid air sliders, an electrostatic sensor, and a soft-handling wafer chuck. With the system, wafer warp is precisely measured before and after film deposition, and the stress distribution is calculated from those measurements. Wafer

Masatoshi Oda; Atsunobu Une; Ikuo Okada; Shinji Shinohara; Yasuo Nakayama; Hideo Yoshihara

1995-01-01

210

Statics and Dynamics Performance Evaluation for a High Precision XYZ Compliant Parallel Micromanipulator  

E-print Network

Statics and Dynamics Performance Evaluation for a High Precision XYZ Compliant Parallel) in terms of statics and dynamics is carried out in this paper, which is quite necessary in designing performed in ANSYS software package, not only the stiffness model is tested by the nonlinear statics

Li, Yangmin

211

High-Precision Calculation of Hartree-Fock Energy of Crystals  

E-print Network

High-Precision Calculation of Hartree-Fock Energy of Crystals M. J. GILLAN,1,2,3 D. ALFÃ?,1,2,3,4 S to calculate the energetics of bulk crystals, there is a need to calculate the Hartree-Fock (HF) energy that the HF energy of crystals can now be calculated using pseudopotentials and plane-wave basis sets

Alfè, Dario

212

Status and prospects of differential navigation and high precision positioning GNSS-technologies in Ukraine  

Microsoft Academic Search

The results of the analysis of status and prospects of differential navigation and high precision positioning using GNSS and their functional augmentations in the world and in Ukraine are stated. The ways of implementation in Ukraine of up-to-date technologies and EGNOS, EUPOS systems, prospects and tasks of development of domestic satellite navigation service are analyzed.

A. Zhalilo; V. Shokalo

2010-01-01

213

High precision relocation of earthquakes at Iliamna Volcano, Alaska Patrick Statz-Boyer a  

E-print Network

High precision relocation of earthquakes at Iliamna Volcano, Alaska Patrick Statz, University of Wisconsin­Madison, Madison, WI 53706, United States b USGS Alaska Science Center, Alaska commenced beneath Iliamna Volcano, Alaska. This activity lasted until early 1997, consisted of over 3000

214

Pulsed frequency modulation techniques for high-precision ultra wideband ranging and positioning  

Microsoft Academic Search

In this paper a novel approach for a high precision local positioning radar using an ultra wideband technique is presented. The concept is based on the standard FMCW (frequency modulated continuous wave) radar principle combined with short pulses to fulfill the emission limits given by the official regulatory authorities. The system combines the advantages of FMCW radar systems and the

Benjamin Waldmann; Robert Weigel; Peter Gulden; Martin Vossiek

2008-01-01

215

High Precision Robust Controller Design for PMSM Servo System with Multi-operating-points  

Microsoft Academic Search

In this paper we propose a high precision robust controller design method for surface mounted PMSM servo system. Feedback linearization method is first applied to transfer the motor plant into a linearized model with an equivalent disturbance. Then a robust controller is designed to compensate the equivalent disturbance. Although some parameters of the control system may deviate seriously from the

Yang Shusheng; Zhong Yisheng

2007-01-01

216

Fixed energy balance window quench correction for high precision LSC 14C dating  

Microsoft Academic Search

In this paper we present the new LSC spectra evaluation method for high precision 14C dating with Quantulus 1220™. The generally used fixed window is replaced with the fixed energy balanced counting window. The lower and upper channel of the window in the multichannel analyzer vary according to the quench level of each individual measurement. The position of the window

Konrad Tudyka; Jacek Pawlyta; Anna Pazdur

2011-01-01

217

C/SiC high-precision lightweight components for optomechanical applications  

NASA Astrophysics Data System (ADS)

We contend that carbon fiber reinforced silicon carbide material (C/SiC), developed by IABG, represents the state- of-the-art for ultra-lightweight, high precision optomechanical structures that must operate in adverse environments and over wide ranges of temperature. C/SiC employs conventional NC machining/milling equipment to rapidly fabricate near-net shape parts, providing substantial schedule, cost, and risk savings for high precision components. Unlike power based SiC ceramics, C/SiC does not experience significant shrinkage during processing, nor does it suffer from incomplete densification. By modifying certain process steps, the thermal and mechanical properties of C/SiC are tunable in certain ranges. This paper focuses on recent advances in C/SiC technology and application of this technology to high precision, lightweight applications such as meter-class optics and optical mounts. We also introduce a design for new, high precision mounts based upon standard optical grade C/SiC (formulation A-3) and a custom formulation of C/SiC (D-4) which was engineered for Schafer Corporation by IABG. The A- 3 and D-4 formulations have a near-perfect CTE match with silicon, making them the ideal material to athermally support ultra-lightweight silicon optics that will operate in a cryogenic environment.

Mueller, Claus E.; Papenburg, Ulrich; Goodman, William A.; Jacoby, Marc T.

2001-03-01

218

Rapid, high-precision potentiometric titration of alkalinity in ocean and sediment pore waters  

Microsoft Academic Search

A system for rapid, high precision potentiometric determination of alkalinity in sea water and sediment pore water is presented. Two titration units were used: a 40 ml unit for seawater and a small volume unit for sediment pore water. Titration time was normally less than 10 minutes per sample, including sample exchange. With a 40 ml sample volume, the relative

Conny Haraldsson; Leif G. Anderson; Martin Hassellöv; Stefan Hulth; Kristina Olsson

1997-01-01

219

Experimental Characterization of Hysteresis in a Revolute Joint for Precision Deployable Structures  

NASA Technical Reports Server (NTRS)

Recent studies of the micro-dynamic behavior of a deployable telescope metering truss have identified instabilities in the equilibrium shape of the truss in response to low-energy dynamic loading. Analyses indicate that these micro-dynamic instabilities arise from stick-slip friction within the truss joints (e.g., hinges and latches). The present study characterizes the low-magnitude quasi-static load cycle response of the precision revolute joints incorporated in the deployable telescope metering truss, and specifically, the hysteretic response of these joints caused by stick-slip friction within the joint. Detailed descriptions are presented of the test setup and data reduction algorithms, including discussions of data-error sources and data-filtering techniques. Test results are presented from thirteen specimens, and the effects of joint preload and manufacturing tolerances are investigated. Using a simplified model of stick-slip friction, a relationship is made between joint load-cycle behavior and micro-dynamic dimensional instabilities in the deployable telescope metering truss.

Lake, Mark S.; Fung, Jimmy; Gloss, Kevin; Liechty, Derek S.

1997-01-01

220

On precise determination of structural and dynamic characteristics of the hydrogen selenide molecule from experimental data  

NASA Astrophysics Data System (ADS)

We realized the method for determining the potential function of the segregated electron state of a polyatomic molecule from experimental data using a hydrogen selenide molecule as an example. Dependences of various spectroscopic parameters on the parameters of the potential function in the natural coordinates were studied. From the obtained data, the potential function of the hydrogen selenide molecule was reconstructed up to the fourth order of smallness.

Sinitsyn, E. A.; Bekhtereva, E. S.; Bulavenkova, A. S.; Ulenikov, O. N.

2007-09-01

221

High-precision Penning trap mass measurements for tests of the Standard Model  

SciTech Connect

With the nowadays achievable accuracy in Penning trap mass spectrometry on short-lived exotic nuclides as well as stable atoms, precision fundamental tests can be performed, among them a test of the Standard Model, in particular with regard to the weak interaction, the CPT symmetry conservation, and the unitarity of the Cabibbo-Kobayashi-Maskawa quark mixing matrix. In addition, accurate mass values of specific nuclides are important for neutrino physics. The presently best tests of the Standard Model with high-precision Penning trap mass spectrometry will be reviewed.

Blaum, Klaus; Eliseev, Sergey [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Nagy, Szilard [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt (Germany)

2010-08-04

222

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

223

Long-range, high-precision absolute distance measurement based on two optoelectronic oscillators.  

PubMed

We demonstrate a scheme for long-range, high-precision absolute distance measurement based on frequency detection using two optoelectronic oscillators to convert distance information to frequency information. The two-oscillator design offers the unique advantage of self-referencing. By taking advantage of the accumulative magnification theory, the error of the measured distance is decreased by approximately 10? fold, which significantly improves the precision of the measured distance. In our experiments, the maximum error is ±1.5???m at an emulated distance of approximately 3.35 km, including a drift error of approximately 1 ?m in the air path due to the variation of environmental conditions. The highest relative measurement precision achieved in our current system is 4.5×10?¹?. PMID:25078190

Wang, Ju; Yu, Jinlong; Miao, Wang; Sun, Bin; Jia, Shi; Wang, Wenrui; Wu, Qiong

2014-08-01

224

Rapid, high-precision potentiometric titration of alkalinity in ocean and sediment pore waters  

NASA Astrophysics Data System (ADS)

A system for rapid, high precision potentiometric determination of alkalinity in sea water and sediment pore water is presented. Two titration units were used: a 40 ml unit for seawater and a small volume unit for sediment pore water. Titration time was normally less than 10 minutes per sample, including sample exchange. With a 40 ml sample volume, the relative standard deviation of the alkalinity obtained in the laboratory was 0.05% and at sea 0.1 %. The small-volume system (0.5-1.5 ml) gave a precision of 0.07%. Five titration points, in two groups after the second equivalence point, were used to evaluate the equivalence volume. Results from equilibrium calculations and computer simulated alkalinity titrations show that it was possible to use a non-modified Gran function [( V 0 +v) ?10 ( E/Z) ] and still achieve good accuracy and precision.

Haraldsson, Conny; Anderson, Leif G.; Hassellöv, Martin; Hulth, Stefan; Olsson, Kristina

1997-12-01

225

Acoustic grating fringe projector for high-speed and high-precision three-dimensional shape measurements  

SciTech Connect

A new acoustic grating fringe projector (AGFP) was developed for high-speed and high-precision 3D measurement. A new acoustic grating fringe projection theory is also proposed to describe the optical system. The AGFP instrument can adjust the spatial phase and period of fringes with unprecedented speed and accuracy. Using rf power proportional-integral-derivative (PID) control and CCD synchronous control, we obtain fringes with fine sinusoidal characteristics and realize high-speed acquisition of image data. Using the device, we obtained a precise phase map for a 3D profile. In addition, the AGFP can work in running fringe mode, which could be applied in other measurement fields.

Yin Xuebing; Zhao Huijie; Zeng Junyu; Qu Yufu

2007-05-20

226

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

227

A high-precision tunable millimeter-wave photonic LO reference for the ALMA telescope  

NASA Astrophysics Data System (ADS)

The Atacama Large Millimeter Array is a radio telescope array of 66 antennas designed for high performance scientific imaging, covering a frequency range of 27-950 GHz. Each antenna has a front end with ten receiving bands, and each band has a local oscillator which is synchronized between all antennas. We describe a high precision tunable millimeter-wave photonic local oscillator reference system, which is used as the synchronizing reference for all ten bands on each receiver.

Shillue, W.; Grammer, W.; Jacques, C.; Meadows, H.; Castro, J.; Banda, J.; Treacy, R.; Masui, Y.; Brito, R.; Huggard, P.; Ellison, B.; Cliche, J.-F.; Ayotte, S.; Babin, A.; Costin, F.; Latrasse, C.; Pelletier, F.; Picard, M.-J.; Poulin, M.; Poulin, P.

2013-06-01

228

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

229

High-precision predictions for the light CP-even Higgs boson mass of the minimal supersymmetric standard model.  

PubMed

For the interpretation of the signal discovered in the Higgs searches at the LHC it will be crucial in particular to discriminate between the minimal Higgs sector realized in the standard model (SM) and its most commonly studied extension, the minimal supersymmetric standard model (MSSM). The measured mass value, having already reached the level of a precision observable with an experimental accuracy of about 500 MeV, plays an important role in this context. In the MSSM the mass of the light CP-even Higgs boson, Mh, can directly be predicted from the other parameters of the model. The accuracy of this prediction should at least match the one of the experimental result. The relatively high mass value of about 126 GeV has led to many investigations where the scalar top quarks are in the multi-TeV range. We improve the prediction for Mh in the MSSM by combining the existing fixed-order result, comprising the full one-loop and leading and subleading two-loop corrections, with a resummation of the leading and subleading logarithmic contributions from the scalar top sector to all orders. In this way for the first time a high-precision prediction for the mass of the light CP-even Higgs boson in the MSSM is possible all the way up to the multi-TeV region of the relevant supersymmetric particles. The results are included in the code FEYNHIGGS. PMID:24765944

Hahn, T; Heinemeyer, S; Hollik, W; Rzehak, H; Weiglein, G

2014-04-11

230

High-Precision Predictions for the Light CP-Even Higgs Boson Mass of the Minimal Supersymmetric Standard Model  

NASA Astrophysics Data System (ADS)

For the interpretation of the signal discovered in the Higgs searches at the LHC it will be crucial in particular to discriminate between the minimal Higgs sector realized in the standard model (SM) and its most commonly studied extension, the minimal supersymmetric standard model (MSSM). The measured mass value, having already reached the level of a precision observable with an experimental accuracy of about 500 MeV, plays an important role in this context. In the MSSM the mass of the light CP-even Higgs boson, Mh, can directly be predicted from the other parameters of the model. The accuracy of this prediction should at least match the one of the experimental result. The relatively high mass value of about 126 GeV has led to many investigations where the scalar top quarks are in the multi-TeV range. We improve the prediction for Mh in the MSSM by combining the existing fixed-order result, comprising the full one-loop and leading and subleading two-loop corrections, with a resummation of the leading and subleading logarithmic contributions from the scalar top sector to all orders. In this way for the first time a high-precision prediction for the mass of the light CP-even Higgs boson in the MSSM is possible all the way up to the multi-TeV region of the relevant supersymmetric particles. The results are included in the code FeynHiggs.

Hahn, T.; Heinemeyer, S.; Hollik, W.; Rzehak, H.; Weiglein, G.

2014-04-01

231

Experimental Sensitivity Table Method for Precision Alignment of Amon-Ra Instrument  

NASA Astrophysics Data System (ADS)

The Amon-Ra instrument is the main optical payload of the proposed EARTHSHINE satellite. It consists of a visible wavelength instrument and an IR energy channel instrument to measure a global Earth albedo. We report a new sensitivity technique for efficient alignment of the visible channel instrument. Whilst the sensitivity table method has been widely used in the alignment process, the straightforward application of the method tends to produce slow process convergence because of shop floor alignment practice uncertainties. We investigated the error sources commonly associated with alignment practices and used them when estimating the Zernike polynomial coefficients. Aided with single center field wavefront error (WFE) measurements and their corresponding Zernike polynomial coefficients, the method involves the construction and use of an experimental, instead of simulated, sensitivity table to be used for alignment state estimations. A trial alignment experiment for the Amon Ra optical system was performed and the results show that 71.28 nm in rms WFE was achieved only after two alignment iterations. This tends to demonstrate its superior performance to the conventional method.

Oh, Eunsong; Ahn, Ki-Beom; Kim, Sug-Whan

2014-09-01

232

High precision titanium isotope measurements on geological samples by high resolution MC-ICPMS  

NASA Astrophysics Data System (ADS)

A method has been developed for the precise and reproducible measurement of Ti isotopes in natural materials using high resolution MC-ICPMS. Instrumental mass fractionation is internally corrected using 49Ti/47Ti. Replicate measurements of synthetic standard solutions, terrestrial rocks, and the carbonaceous chondrite Allende yield a long-term reproducibility (2[sigma]) of 0.28[var epsilon], 0.34[var epsilon], and 0.28[var epsilon] for 50Ti/47Ti, 48Ti/47Ti, and 46Ti/47Ti, respectively. Isobaric interferences from 46,48Ca+, 50V+, 50Cr+, and doubly charged Zr can be corrected for reliably in separated Ti solutions with Ca/Ti < 5, V/Ti < 0.3, Cr/Ti < 0.2, and Zr/Ti < 1, respectively. Such elemental ratios are achieved easily in most samples using the anion-exchange procedure presented. Single and double charged polyatomic ions can either be resolved, e.g., 14N36Ar+, or do not compromise the measurements. The method has been successfully applied to terrestrial rocks, meteorites, and various mineral separates. Terrestrial samples and standards agree within analytical uncertainties but are consistently different from the recommended values of Niederer et al. [F.R. Niederer, D.A. Papanastassiou, G.J. Wasserburg, Geochim. Cosmochim. Acta 45 (1981) 1017] with the largest effect on 50Ti/47Ti. The new results provide evidence that the recommended terrestrial 50Ti/47Ti is not well constrained; our data are higher by ~13[var epsilon] than the recommended value. Better agreement is found with the values recommended by Heydegger et al. [H.R. Heydegger, J.J. Foster, W. Compston, Earth Planet. Sci. Lett. 58 (1982) 406]. Our best estimate for the isotopic composition of terrestrial Ti (relative to 49Ti/47Ti = 0.749766) is: 50Ti/47Ti = 0.73010, 48Ti/47Ti = 10.06884, and 46Ti/47Ti = 1.09325. This corresponds to an atomic weight of 47.877, significantly different from the value of 47.867 recommended by IUPAC. A 50Ti/47Ti anomaly for bulk Allende of 3.37 ± 0.51[var epsilon] is found, while for 48Ti/47Ti and 46Ti/47Ti the data are identical to the terrestrial value within the uncertainties. This is consistent with other recently reported differences between the bulk Earth and chondrites in neutron-rich nuclides.

Leya, Ingo; Schönbächler, Maria; Wiechert, Uwe; Krähenbühl, Urs; Halliday, Alex N.

2007-05-01

233

A discrete time-varying internal model-based approach for high precision tracking of a multi-axis servo gantry.  

PubMed

In this paper, we consider the discrete time-varying internal model-based control design for high precision tracking of complicated reference trajectories generated by time-varying systems. Based on a novel parallel time-varying internal model structure, asymptotic tracking conditions for the design of internal model units are developed, and a low order robust time-varying stabilizer is further synthesized. In a discrete time setting, the high precision tracking control architecture is deployed on a Voice Coil Motor (VCM) actuated servo gantry system, where numerical simulations and real time experimental results are provided, achieving the tracking errors around 3.5‰ for frequency-varying signals. PMID:24957273

Zhang, Zhen; Yan, Peng; Jiang, Huan; Ye, Peiqing

2014-09-01

234

High Precision Tracking Control based on Pseudo-Inverse Feedforward Control System for Next-Generation Optical Disks  

NASA Astrophysics Data System (ADS)

Optical disk drive systems must realize high-precision tracking control. For this purpose, we have already proposed a tracking control system that is composed of a high gain servo controller (HGSC) and a perfect tracking controller (PTC). The conventional feedforward tracking control system adequately suppresses the tracking error caused by track eccentricity. However, the PTC system in the conventional system is complicated. Therefore, the PTC system embedded on a digital signal processor (DSP) cannot realize fast sampling time and the conventional system has a speedup limitation in the optical disk tracking control system. Hence, in this paper, we propose a new high-speed and high-precision feedforward tracking control system that uses a pseudo-inverse matrix. The proposed system consists of the pseudo-inverse feedforward control (P-IFFC). The proposed system realizes simple and quick execution in a digital signal processor software servo. Our experimental results confirm that the proposed system effectively suppresses the tracking error under a condition of the 7200 rpm disk rotation speed of DVD+R. In addition, the conventional systems and the proposed system with a pseudo-inverse matrix are compared in terms of processing time and tracking error.

Ogata, Tokoku; Nakazaki, Tatsuya; Sakimura, Naohide; Ohishi, Kiyoshi; Miyazaki, Toshimasa; Koide, Daiichi; Tokumaru, Haruki; Takano, Yoshimichi

2012-08-01

235

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

236

Direct high-precision measurement of the magnetic moment of the proton  

NASA Astrophysics Data System (ADS)

One of the fundamental properties of the proton is its magnetic moment, µp. So far µp has been measured only indirectly, by analysing the spectrum of an atomic hydrogen maser in a magnetic field. Here we report the direct high-precision measurement of the magnetic moment of a single proton using the double Penning-trap technique. We drive proton-spin quantum jumps by a magnetic radio-frequency field in a Penning trap with a homogeneous magnetic field. The induced spin transitions are detected in a second trap with a strong superimposed magnetic inhomogeneity. This enables the measurement of the spin-flip probability as a function of the drive frequency. In each measurement the proton's cyclotron frequency is used to determine the magnetic field of the trap. From the normalized resonance curve, we extract the particle's magnetic moment in terms of the nuclear magneton: ?p = 2.792847350(9)?N. This measurement outperforms previous Penning-trap measurements in terms of precision by a factor of about 760. It improves the precision of the forty-year-old indirect measurement, in which significant theoretical bound state corrections were required to obtain µp, by a factor of 3. By application of this method to the antiproton magnetic moment, the fractional precision of the recently reported value can be improved by a factor of at least 1,000. Combined with the present result, this will provide a stringent test of matter/antimatter symmetry with baryons.

Mooser, A.; Ulmer, S.; Blaum, K.; Franke, K.; Kracke, H.; Leiteritz, C.; Quint, W.; Rodegheri, C. C.; Smorra, C.; Walz, J.

2014-05-01

237

A Technique for Extracting Highly Precise Photometry for the Two-Wheeled Kepler Mission  

E-print Network

The original Kepler mission achieved high photometric precision thanks to ultra-stable pointing enabled by use of four reaction wheels. The loss of two of these reaction wheels reduced the telescope's ability to point precisely for extended periods of time, and as a result, the photometric precision has suffered. We present a technique for generating photometric light curves from pixel-level data obtained with the two-wheeled extended Kepler mission, K2. Our photometric technique accounts for the non-uniform pixel response function of the Kepler detectors by correlating flux measurements with the spacecraft's pointing and removing the dependence. When we apply our technique to the ensemble of stars observed during the Kepler Two-Wheel Concept Engineering Test, we find improvements over raw K2 photometry by factors of 2-5, with noise properties qualitatively similar to Kepler targets at the same magnitudes. We find evidence that the improvement in photometric precision depends on each target's position in the ...

Vanderburg, Andrew

2014-01-01

238

High-precision image aided inertial navigation with known features: observability analysis and performance evaluation.  

PubMed

A high-precision image-aided inertial navigation system (INS) is proposed as an alternative to the carrier-phase-based differential Global Navigation Satellite Systems (CDGNSSs) when satellite-based navigation systems are unavailable. In this paper, the image/INS integrated algorithm is modeled by a tightly-coupled iterative extended Kalman filter (IEKF). Tightly-coupled integration ensures that the integrated system is reliable, even if few known feature points (i.e., less than three) are observed in the images. A new global observability analysis of this tightly-coupled integration is presented to guarantee that the system is observable under the necessary conditions. The analysis conclusions were verified by simulations and field tests. The field tests also indicate that high-precision position (centimeter-level) and attitude (half-degree-level)-integrated solutions can be achieved in a global reference. PMID:25330046

Jiang, Weiping; Wang, Li; Niu, Xiaoji; Zhang, Quan; Zhang, Hui; Tang, Min; Hu, Xiangyun

2014-01-01

239

Optical timing receiver for the NASA laser ranging system. Part 2: High precision time interval digitizer  

NASA Technical Reports Server (NTRS)

The development of a high precision time interval digitizer is described. The time digitizer is a 10 psec resolution stop watch covering a range of up to 340 msec. The measured time interval is determined as a separation between leading edges of a pair of pulses applied externally to the start input and the stop input of the digitizer. Employing an interpolation techniques and a 50 MHz high precision master oscillator, the equivalent of a 100 GHz clock frequency standard is achieved. Absolute accuracy and stability of the digitizer are determined by the external 50 MHz master oscillator, which serves as a standard time marker. The start and stop pulses are fast 1 nsec rise time signals, according to the Nuclear Instrument means of tunnel diode discriminators. Firing level of the discriminator define start and stop points between which the time interval is digitized.

Leskovar, B.; Turko, B.

1977-01-01

240

High-precision measurement of pixel positions in a charge-coupled device.  

PubMed

The high level of spatial uniformity in modern CCD's makes them excellent devices for astrometric instruments. However, at the level of accuracy envisioned by the more ambitious projects such as the Astrometric Imaging Telescope, current technology produces CCD's with significant pixel registration errors. We describe a technique for making high-precision measurements of relative pixel positions. We measured CCD's manufactured for the Wide Field Planetary Camera II installed in the Hubble Space Telescope. These CCD's are shown to have significant step-and-repeat errors of 0.033 pixel along every 34th row, as well as a 0.003-pixel curvature along 34-pixel stripes. The source of these errors is described. Our experiments achieved a per-pixel accuracy of 0.011 pixel. The ultimate shot-noise limited precision of the method is less than 0.001 pixel. PMID:21060522

Shaklan, S; Sharman, M C; Pravdo, S H

1995-10-10

241

High-Precision Image Aided Inertial Navigation with Known Features: Observability Analysis and Performance Evaluation  

PubMed Central

A high-precision image-aided inertial navigation system (INS) is proposed as an alternative to the carrier-phase-based differential Global Navigation Satellite Systems (CDGNSSs) when satellite-based navigation systems are unavailable. In this paper, the image/INS integrated algorithm is modeled by a tightly-coupled iterative extended Kalman filter (IEKF). Tightly-coupled integration ensures that the integrated system is reliable, even if few known feature points (i.e., less than three) are observed in the images. A new global observability analysis of this tightly-coupled integration is presented to guarantee that the system is observable under the necessary conditions. The analysis conclusions were verified by simulations and field tests. The field tests also indicate that high-precision position (centimeter-level) and attitude (half-degree-level)-integrated solutions can be achieved in a global reference. PMID:25330046

Jiang, Weiping; Wang, Li; Niu, Xiaoji; Zhang, Quan; Zhang, Hui; Tang, Min; Hu, Xiangyun

2014-01-01

242

Development of a high-precision straightness measuring system with DVD pick-up head  

Microsoft Academic Search

A low-cost and high-precision straightness measurement system using a DVD pick-up head has been developed in this research. By removing its objective lens the pick-up head of a commercial DVD player possesses excellent properties of stable laser power, collimated laser beam, circular Gaussian distribution and sensitive photodetectors. A moving knife-edge piece is placed between the pick-up head and a plane

Kuang-Chao Fan; Chih-Liang Chu; Jarn-Lien Liao; Jong-I. Mou

2003-01-01

243

Detuned Twin-Signal-Recycling for ultra-high precision interferometers  

E-print Network

We propose a new interferometer technique for high precision phase measurements such as those in gravitational wave detection. The technique utilizes a pair of optically coupled resonators that provides identical resonance conditions for the upper as well the lower phase modulation signal sidebands. This symmetry significantly reduces the noise spectral density in a wide frequency band compared with single sideband recycling topologies of current and planned gravitational wave detectors. Furthermore the application of squeezed states of light becomes less demanding.

Andre Thuering; Roman Schnabel; Harald Lueck; Karsten Danzmann

2007-07-03

244

High precision Lu–Hf geochronology of Eocene eclogite-facies rocks from Syros, Cyclades, Greece  

Microsoft Academic Search

Garnet-bearing high pressure, low temperature (HP\\/LT) metamorphic rocks of the Cycladic Blueschist Unit have been investigated by Lu–Hf geochronology. Eclogites from Syros Island yield precise ages of 52.2±0.3 Ma, 51.4±0.4 Ma, and 50±2 Ma. Preserved major- and trace element growth zoning in garnet suggests that the closure temperature of the Lu–Hf system in garnet was higher than the estimated peak metamorphic temperature of

Markus Lagos; Erik E. Scherer; Frank Tomaschek; Carsten Münker; Mark Keiter; Jasper Berndt; Chris Ballhaus

2007-01-01

245

Ultrashort pulse Cr4+:YAG laser for high precision infrared frequency interval measurements  

PubMed Central

A cavity stabilized, SESAM mode-locked Cr4+:YAG laser capable of generating sub-100 fs pulses has been developed. Locking the 130-MHz pulse repetition frequency to that of a hydrogen maser-referenced frequency synthesizer provides a 30-nm wide frequency comb for the 1530-nm wavelength region. In conjunction with a pair of acetylene stabilized, external cavity diode lasers, this laser provides a high precision measurement tool for the determination of acetylene transition frequencies. PMID:19498916

Alcock, A. J.; Ma, P.; Poole, P. J.; Chepurov, S.; Czajkowski, A.; Bernard, J. E.; Madej, A. A.; Fraser, J. M.; Mitchell, I. V.; Sorokina, I. T.; Sorokin, E.

2010-01-01

246

High Precision Topographic Mapping at Chang'E-3 Landing Site with Multi-Source Data  

NASA Astrophysics Data System (ADS)

Chang'e-3 (CE-3) is the first lander and rover of China following the success of Chang'e-1 and Chang'e-2 (CE-2) orbiters. High precision topographic mapping can provide detailed terrain information to ensure the safety of the rover as well as to support scientific investigations. In this research, multi-source data are co-registered into a uniform geographic framework for high precision topographic mapping at the CE-3 landing site. CE-2 CCD images with 7 m- and 1.5 m- resolutions are registered using selfcalibration bundle adjustment method with ground control points (GCPs) selected from LRO WAC mosaic map and LOLA DTM. The trajectory of CE-3 descent images are recovered using self-calibration free net bundle adjustment, and then the topographic data is rectified by absolute orientation with GCPs selected from the adjusted CE-2 DEM and DOM. Finally, these topographic data are integrated into the same geographic framework for unified, multi-scale, high precision mapping of the CE-3 landing site. Key technologies and the mapping products of this research have been used to support the surface operations of CE-3 mission.

Liu, Y.; Liu, B.; Xu, B.; Liu, Z.; Di, K.; Zhou, J.

2014-04-01

247

Next generation KATRIN high precision voltage divider for voltages up to 65kV  

NASA Astrophysics Data System (ADS)

The KATRIN (KArlsruhe TRItium Neutrino) experiment aims to determine the mass of the electron antineutrino with a sensitivity of 200 meV by precisely measuring the electron spectrum of the tritium beta decay. This will be done by the use of a retarding spectrometer of the MAC-E-Filter type. To achieve the desired sensitivity the stability of the retarding potential of -18.6 kV has to be monitored with a precision of 3 ppm over at least two months. Since this is not feasible with commercial devices, two ppm-class high voltage dividers were developed, following the concept of the standard divider for DC voltages of up to 100 kV of the Physikalisch-Technische Bundesanstalt (PTB). In order to reach such high accuracies different effects have to be considered. The two most important ones are the temperature dependence of resistance and leakage currents, caused by insulators or corona discharges. For the second divider improvements were made concerning the high-precision resistors and the thermal design of the divider. The improved resistors are the result of a cooperation with the manufacturer. The design improvements, the investigation and the selection of the resistors, the built-in ripple probe and the calibrations at PTB will be reported here. The latter demonstrated a stability of about 0.1 ppm/month over a period of two years.

Bauer, S.; Berendes, R.; Hochschulz, F.; Ortjohann, H.-W.; Rosendahl, S.; Thümmler, T.; Schmidt, M.; Weinheimer, C.

2013-10-01

248

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

249

High-speed precision UV drilling with frequency-doubled copper vapor lasers  

NASA Astrophysics Data System (ADS)

The copper vapor laser (CVL) is an efficient, high average power, high pulse rate visible laser, emitting in the green and the yellow. Previous applications of CVLs have been limited to those requiring a high power visible laser source but with no specific need for high output beam quality. Recently we have made substantial progress in understanding the factors that influence CVL beam quality. As a result we are now able to achieve efficient non-linear frequency conversion to produce a number of ultraviolet wavelengths with near- diffraction limited beam quality. The high repetition rate and low divergence uv output of the frequency-doubled CVL makes it an attractive alternative to the excimer laser for a number of applications, including high-speed precision hole-drilling, cutting and scoring in polymers and for deep-uv photolithography. We report here recent developments that have led to efficient generation of uv wavelengths from copper vapor lasers and we demonstrate its potential as a laser source for high-speed precision ultraviolet micromachining.

Ramsay, Donald J.; Glover, Alison C. J.; Coutts, David W.; Piper, James A.

1994-02-01

250

A Flexile and High Precision Calibration Method for Binocular Structured Light Scanning System  

PubMed Central

3D (three-dimensional) structured light scanning system is widely used in the field of reverse engineering, quality inspection, and so forth. Camera calibration is the key for scanning precision. Currently, 2D (two-dimensional) or 3D fine processed calibration reference object is usually applied for high calibration precision, which is difficult to operate and the cost is high. In this paper, a novel calibration method is proposed with a scale bar and some artificial coded targets placed randomly in the measuring volume. The principle of the proposed method is based on hierarchical self-calibration and bundle adjustment. We get initial intrinsic parameters from images. Initial extrinsic parameters in projective space are estimated with the method of factorization and then upgraded to Euclidean space with orthogonality of rotation matrix and rank 3 of the absolute quadric as constraint. Last, all camera parameters are refined through bundle adjustment. Real experiments show that the proposed method is robust, and has the same precision level as the result using delicate artificial reference object, but the hardware cost is very low compared with the current calibration method used in 3D structured light scanning system.

Yuan, Jianying; Wang, Qiong; Li, Bailin

2014-01-01

251

High-precision wavelength calibration of astronomical spectrographs with laser frequency combs  

NASA Astrophysics Data System (ADS)

We describe a possible new technique for precise wavelength calibration of high-resolution astronomical spectrographs using femtosecond-pulsed mode-locked lasers controlled by stable oscillators such as atomic clocks. Such `frequency combs' provide a series of narrow modes which are uniformly spaced according to the laser's pulse repetition rate and whose absolute frequencies are known a priori with relative precision better than 10-12. Simulations of frequency comb spectra show that the photon-limited wavelength calibration precision achievable with existing echelle spectrographs should be ~1cms-1 when integrated over a 4000 Å range. Moreover, comb spectra may be used to accurately characterize distortions of the wavelength scale introduced by the spectrograph and detector system. The simulations show that frequency combs with pulse repetition rates of 5-30GHz are required, given the typical resolving power of existing and possible future echelle spectrographs. Achieving such high repetition rates, together with the desire to produce all comb modes with uniform intensity over the entire optical range, represents the only significant challenges in the design of a practical system. Frequency comb systems may remove wavelength calibration uncertainties from all practical spectroscopic experiments, even those combining data from different telescopes over many decades.

Murphy, M. T.; Udem, Th.; Holzwarth, R.; Sizmann, A.; Pasquini, L.; Araujo-Hauck, C.; Dekker, H.; D'Odorico, S.; Fischer, M.; Hänsch, T. W.; Manescau, A.

2007-09-01

252

High Precision Oxygen Three Isotope Analysis of Wild-2 Particles and Anhydrous Chondritic Interplanetary Dust Particles  

NASA Technical Reports Server (NTRS)

One of the most important discoveries from comet Wild-2 samples was observation of crystalline silicate particles that resemble chondrules and CAIs in carbonaceous chondrites. Previous oxygen isotope analyses of crystalline silicate terminal particles showed heterogeneous oxygen isotope ratios with delta(sup 18)O to approx. delta(sup 17)O down to -50% in the CAI-like particle Inti, a relict olivine grain in Gozen-sama, and an olivine particle. However, many Wild-2 particles as well as ferromagnesian silicates in anhydrous interplanetary dust particles (IDPs) showed Delta(sup 17)O values that cluster around -2%. In carbonaceous chondrites, chondrules seem to show two major isotope reservoirs with Delta(sup 17)O values at -5% and -2%. It was suggested that the Delta(sup 17)O = -2% is the common oxygen isotope reservoir for carbonaceous chondrite chondrules and cometary dust, from the outer asteroid belt to the Kuiper belt region. However, a larger dataset with high precision isotope analyses (+/-1-2%) is still needed to resolve the similarities or distinctions among Wild-2 particles, IDPs and chondrules in meteorites. We have made signifi-cant efforts to establish routine analyses of small particles (< or =10micronsm) at 1-2% precision using IMS-1280 at WiscSIMS laboratory. Here we report new results of high precision oxygen isotope analyses of Wild-2 particles and anhydrous chondritic IDPs, and discuss the relationship between the cometary dust and carbonaceous chondrite chondrules.

Nakashima, D.; Ushikubo, T.; Zolensky, Michael E.; Weisberg, M. K.; Joswiak, D. J.; Brownlee, D. E.; Matrajt, G.; Kita, N. T.

2011-01-01

253

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

2011-08-01

254

a High-Precision Branching-Ratio Measurement for the Superallowed ?+ Emitter 74Rb  

NASA Astrophysics Data System (ADS)

Precision measurements of superallowed Fermi beta decay allow for tests of the Cabibbo-Kobayashi-Maskawa matrix (CKM) unitarity, the conserved vector current hypothesis, and the magnitude of isospin-symmetry-breaking effects in nuclei. A high-precision measurement of the branching ratio for the ?+ decay of 74Rb has been performed at the Isotope Separator and ACcelerator (ISAC) facility at TRIUMF. The 8? spectrometer, an array of 20 close-packed HPGe detectors, was used to detect gamma rays emitted following the decay of 74Rb. PACES, an array of 5 Si(Li) detectors, was used to detect emitted conversion electrons, while SCEPTAR, an array of plastic scintillators, was used to detect emitted beta particles. A total of 51? rays have been identified following the decay of 21 excited states in the daughter nucleus 74Kr.

Dunlop, R.; Chagnon-Lessard, S.; Finlay, P.; Garrett, P. E.; Hadinia, B.; Leach, K. G.; Svensson, C. E.; Wong, J.; Ball, G.; Garnsworthy, A. B.; Glister, J.; Hackman, G.; Tardiff, E. R.; Triambak, S.; Williams, S. J.; Leslie, J. R.; Andreoiu, C.; Chester, A.; Cross, D.; Starosta, K.; Yates, S. W.; Zganjar, E. F.

2013-03-01

255

Communication: High precision sub-Doppler infrared spectroscopy of the HeH+ ion  

NASA Astrophysics Data System (ADS)

The hydrohelium cation, HeH+, serves as an important benchmark for ab initio calculations that take into account non-adiabatic, relativistic, and quantum electrodynamic effects. Such calculations are capable of predicting molecular transitions to an accuracy of ˜300 MHz or less. However, in order to continue to push the boundaries on these calculations, new measurements of these transitions are required. Here we measure seven rovibrational transitions in the fundamental vibrational band to a precision of ˜1 MHz using the technique of Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy. These newly measured transitions are included in a fit to the rotation-vibration term values to derive refined spectroscopic constants in the v = 0 and v = 1 vibrational states, as well as to calculate rotation-vibration energy levels with high precision.

Perry, Adam J.; Hodges, James N.; Markus, Charles R.; Kocheril, G. Stephen; McCall, Benjamin J.

2014-09-01

256

Towards a high-precision measurement of the antiproton magnetic moment  

NASA Astrophysics Data System (ADS)

The recent observation of single spins flips with a single proton in a Penning trap opens the way to measure the proton magnetic moment with high precision. Based on this success, which has been achieved with our apparatus at the University of Mainz, we demonstrated recently the first application of the so called double Penning-trap method with a single proton. This is a major step towards a measurement of the proton magnetic moment with ppb precision. To apply this method to a single trapped antiproton our collaboration is currently setting up a companion experiment at the antiproton decelerator of CERN. This effort is recognized as the Baryon Antibaryon Symmetry Experiment (BASE). A comparison of both magnetic moment values will provide a stringent test of CPT invariance with baryons.

Smorra, C.; Blaum, K.; Franke, K.; Matsuda, Y.; Mooser, A.; Nagahama, H.; Ospelkaus, C.; Quint, W.; Schneider, G.; Van Gorp, S.; Walz, J.; Yamazaki, Y.; Ulmer, S.

2014-02-01

257

Numerical Integration of the Polygonal n-body Problem in High Precision Arithmetic  

NASA Astrophysics Data System (ADS)

The paper presents a computer algebra program dedicated to the synthesis and generation of numerical code for the integration of the n-body problem using an arbitrary precision arithmetic library. The program is able to apply several numerical methods specified in the high level programming language of the computer algebra system and to generate efficient low level code. The library is tested in the numerical integration of the general n-body problem starting with the initial conditions where the equal mass bodies having equal velocities are placed at the vertices and in the center of a regular polygon. In this case the problem has analytical solution but proves to be hard to integrate numerically in standard double precision due to the instability of the symmetric configuration.

Peter, D.; Zapotinschi, R.; Tóth, A. E.

2007-05-01

258

Communication: High precision sub-Doppler infrared spectroscopy of the HeH(+) ion.  

PubMed

The hydrohelium cation, HeH(+), serves as an important benchmark for ab initio calculations that take into account non-adiabatic, relativistic, and quantum electrodynamic effects. Such calculations are capable of predicting molecular transitions to an accuracy of ?300 MHz or less. However, in order to continue to push the boundaries on these calculations, new measurements of these transitions are required. Here we measure seven rovibrational transitions in the fundamental vibrational band to a precision of ?1 MHz using the technique of Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy. These newly measured transitions are included in a fit to the rotation-vibration term values to derive refined spectroscopic constants in the v = 0 and v = 1 vibrational states, as well as to calculate rotation-vibration energy levels with high precision. PMID:25217893

Perry, Adam J; Hodges, James N; Markus, Charles R; Kocheril, G Stephen; McCall, Benjamin J

2014-09-14

259

Lightweight Metal Matrix Composite Segmented for Manufacturing High-Precision Mirrors  

NASA Technical Reports Server (NTRS)

High-precision mirrors for space applications are traditionally manufactured from one piece of material, such as lightweight glass sandwich or beryllium. The purpose of this project was to develop and test the feasibility of a manufacturing process capable of producing mirrors out of welded segments of AlBeMet(Registered Trademark) (AM162H). AlBeMet(Registered Trademark) is a HIP'd (hot isostatic pressed) material containing approximately 62% beryllium and 38% aluminum. As a result, AlBeMet shares many of the benefits of both of those materials for use in high performance mirrors, while minimizing many of their weaknesses.

Vudler, Vladimir

2012-01-01

260

[Spectral scanning measurement of high-precision solar irradiance-meter].  

PubMed

In order to measure the radiation of the sun absolutely and retrieve the characterization of the atmosphere precisely, a high-precision solar spectral irradiance meter working in 0.4-1.0 microm band was developed. A Fèry prism was employed to disperse the incident sunlight and a closed-loop control method was adopted for spectral scanning in this solar irradiance meter. The design of spectral scanning measurement was depicted in detail. The design requirements of Fèry prism were given and spectral dispersion was achieved by single element. The trap detectors were used to ensure precise spectral measurement. According to the parameters of the trap detectors, the demands and method of temperature control were introduced. The design of spectral scanning structure was introduced, and wavelengths were positioned accurately. The requirements for parameters, stability and power supply of voice coil actuator were given and the wavelength position error of 0. 025% was achieved. Spectral scanning measurement of 0.4-1.0 microm was accomplished in outdoor experiments. A comparison was carried out with visible-short wave infrared spectrometer and auto-sunphotometer (CE318). Results indicate that absorption peak locations of spectral scanning measurement of irradiance meter are correct, and the relative deviation from CE318 measurements is less than 0.13% for all day, and the relative deviation of optical depth in visible and near infrared band is less than 2% and 5%, respectively. PMID:25208375

Liu, En-Chao; Li, Xin; Zhang, Yan-Na; Li, Wen-Wei; Zheng, Xiao-Bing

2014-03-01

261

Direct high-precision measurement of the magnetic moment of the proton  

E-print Network

The spin-magnetic moment of the proton $\\mu_p$ is a fundamental property of this particle. So far $\\mu_p$ has only been measured indirectly, analysing the spectrum of an atomic hydrogen maser in a magnetic field. Here, we report the direct high-precision measurement of the magnetic moment of a single proton using the double Penning-trap technique. We drive proton-spin quantum jumps by a magnetic radio-frequency field in a Penning trap with a homogeneous magnetic field. The induced spin-transitions are detected in a second trap with a strong superimposed magnetic inhomogeneity. This enables the measurement of the spin-flip probability as a function of the drive frequency. In each measurement the proton's cyclotron frequency is used to determine the magnetic field of the trap. From the normalized resonance curve, we extract the particle's magnetic moment in units of the nuclear magneton $\\mu_p=2.792847350(9)\\mu_N$. This measurement outperforms previous Penning trap measurements in terms of precision by a factor of about 760. It improves the precision of the forty year old indirect measurement, in which significant theoretical bound state corrections were required to obtain $\\mu_p$, by a factor of 3. By application of this method to the antiproton magnetic moment $\\mu_{\\bar{p}}$ the fractional precision of the recently reported value can be improved by a factor of at least 1000. Combined with the present result, this will provide a stringent test of matter/antimatter symmetry with baryons.

A. Mooser; S. Ulmer; K. Blaum; K. Franke; H. Kracke; C. Leiteritz; W. Quint; C. C. Rodegheri; C. Smorra; J. Walz

2014-06-18

262

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

263

An optical fan for light beams for high-precision optical measurements and optical switching  

E-print Network

The polarization and orbital angular momentum properties of light are of great importance in optical science and technology in the fields of high precision optical measurements and high capacity and high speed optical communications. Here we show, a totally new method, based on a combination of these two properties and using the thermal dispersion and electro-optical effect of birefringent crystals, the construction of a simple and robust scheme to rotate a light beam like a fan. Using a computer-based digital image processing technique, we determine the temperature and the thermal dispersion difference of the crystal with high resolution. We also use the rotation phenomenon to realize thermo-optic and electro-optic switches. The basic operating principles for measurement and switching processes are presented in detail. The methods developed here will have wide practical applicability in various fields, including remote sensing, materials science and optical communication networks.

Zhou, Zhi-Yuan; Ding, Dong-Sheng; Jiang, Yun-Kun; Zhang, Wei; Shi, Shuai; Shi, Bao-Sen; Guo, Guang-Can

2014-01-01

264

An optical fan for light beams for high-precision optical measurements and optical switching  

E-print Network

The polarization and orbital angular momentum properties of light are of great importance in optical science and technology in the fields of high precision optical measurements and high capacity and high speed optical communications. Here we show, a totally new method, based on a combination of these two properties and using the thermal dispersion and electro-optical effect of birefringent crystals, the construction of a simple and robust scheme to rotate a light beam like a fan. Using a computer-based digital image processing technique, we determine the temperature and the thermal dispersion difference of the crystal with high resolution. We also use the rotation phenomenon to realize thermo-optic and electro-optic switches. The basic operating principles for measurement and switching processes are presented in detail. The methods developed here will have wide practical applicability in various fields, including remote sensing, materials science and optical communication networks.

Zhi-Yuan Zhou; Yan Li; Dong-Sheng Ding; Yun-Kun Jiang; Wei Zhang; Shuai Shi; Bao-Sen Shi; Guang-Can Guo

2014-05-08

265

Note: Three-dimensional linearization of optical trap position detection for precise high speed diffusion measurements.  

PubMed

Studies of the details of Brownian motion, hydrodynamic of colloids, or protein diffusion measurements all require high temporal and spatial resolution of the position detector and a means to trap the colloid. Optical trap based thermal noise imaging employing a quadrant photodiode as detector provides such a method. However, optical trapping requires an objective with high numerical aperture resulting in highly nonlinear position signal and significant cross-dependence of the three spatial directions. Local diffusion measurements are especially susceptible to distance errors. Here, we present a position calibration method, which corrects nonlinearities sufficiently to allow precise local diffusion measurement throughout the entire trapping volume. This correction permits us to obtain high-resolution two- and three-dimensional diffusion maps. PMID:25085189

Hsu, Y-H; Pralle, A

2014-07-01

266

Optical vortex beam based optical fan for high-precision optical measurements and optical switching  

NASA Astrophysics Data System (ADS)

The polarization and orbital angular momentum properties of light are of great importance in optical science and technology in the fields of high precision optical measurements and high capacity and high speed optical communications. Here we show, a totally new method, based on a combination of these two properties and using the thermal dispersion and electro-optical effect of birefringent crystals, the construction of a simple and robust scheme to rotate a light beam like a fan. Using a computer-based digital image processing technique, we determine the temperature and the thermal dispersion difference of the crystal with high resolution. We also use the rotation phenomenon to realize thermo-optic and electro-optic switches. The basic operating principles for measurement and switching processes are presented in detail. The methods developed here will have wide practical applicability in various fields, including remote sensing, materials science and optical communication networks.

Zhou, Zhi-Yuan; Li, Yan; Ding, Dong-Sheng; Zhang, Wei; Shi, Shuai; Shi, Bao-Sen

2014-09-01

267

High-Precision Distribution of Highly Stable Optical Pulse Trains with 8.8 × 10?19 instability  

PubMed Central

The high-precision distribution of optical pulse trains via fibre links has had a considerable impact in many fields. In most published work, the accuracy is still fundamentally limited by unavoidable noise sources, such as thermal and shot noise from conventional photodiodes and thermal noise from mixers. Here, we demonstrate a new high-precision timing distribution system that uses a highly precise phase detector to obviously reduce the effect of these limitations. Instead of using photodiodes and microwave mixers, we use several fibre Sagnac-loop-based optical-microwave phase detectors (OM-PDs) to achieve optical-electrical conversion and phase measurements, thereby suppressing the sources of noise and achieving ultra-high accuracy. The results of a distribution experiment using a 10-km fibre link indicate that our system exhibits a residual instability of 2.0 × 10?15 at1?s and8.8 × 10?19 at 40,000?s and an integrated timing jitter as low as 3.8?fs in a bandwidth of 1?Hz to 100?kHz. This low instability and timing jitter make it possible for our system to be used in the distribution of optical-clock signals or in applications that require extremely accurate frequency/time synchronisation. PMID:24870442

Ning, B.; Zhang, S. Y.; Hou, D.; Wu, J. T.; Li, Z. B.; Zhao, J. Y.

2014-01-01

268

High-Precision Distribution of Highly Stable Optical Pulse Trains with 8.8 × 10-19 instability  

NASA Astrophysics Data System (ADS)

The high-precision distribution of optical pulse trains via fibre links has had a considerable impact in many fields. In most published work, the accuracy is still fundamentally limited by unavoidable noise sources, such as thermal and shot noise from conventional photodiodes and thermal noise from mixers. Here, we demonstrate a new high-precision timing distribution system that uses a highly precise phase detector to obviously reduce the effect of these limitations. Instead of using photodiodes and microwave mixers, we use several fibre Sagnac-loop-based optical-microwave phase detectors (OM-PDs) to achieve optical-electrical conversion and phase measurements, thereby suppressing the sources of noise and achieving ultra-high accuracy. The results of a distribution experiment using a 10-km fibre link indicate that our system exhibits a residual instability of 2.0 × 10-15 at1 s and8.8 × 10-19 at 40,000 s and an integrated timing jitter as low as 3.8 fs in a bandwidth of 1 Hz to 100 kHz. This low instability and timing jitter make it possible for our system to be used in the distribution of optical-clock signals or in applications that require extremely accurate frequency/time synchronisation.

Ning, B.; Zhang, S. Y.; Hou, D.; Wu, J. T.; Li, Z. B.; Zhao, J. Y.

2014-05-01

269

A novel approach for high precision rapid potentiometric titrations: application to hydrazine assay.  

PubMed

We propose a high precision rapid personal computer (PC) based potentiometric titration technique using a specially designed mini-cell to carry out redox titrations for assay of chemicals in quality control laboratories attached to industrial, R&D, and nuclear establishments. Using this technique a few microlitre of sample (50-100 ?l) in a total volume of ~2 ml solution can be titrated and the waste generated after titration is extremely low comparing to that obtained from the conventional titration technique. The entire titration including online data acquisition followed by immediate offline analysis of data to get information about concentration of unknown sample is completed within a couple of minutes (about 2 min). This facility has been created using a new class of sensors, viz., pulsating sensors developed in-house. The basic concept in designing such instrument and the salient features of the titration device are presented in this paper. The performance of the titration facility was examined by conducting some of the high resolution redox titrations using dilute solutions--hydrazine against KIO(3) in HCl medium, Fe(II) against Ce(IV) and uranium using Davies-Gray method. The precision of titrations using this innovative approach lies between 0.048% and 1.0% relative standard deviation in different redox titrations. With the evolution of this rapid PC based titrator it was possible to develop a simple but high precision potentiometric titration technique for quick determination of hydrazine in nuclear fuel dissolver solution in the context of reprocessing of spent nuclear fuel in fast breeder reactors. PMID:22128994

Sahoo, P; Malathi, N; Ananthanarayanan, R; Praveen, K; Murali, N

2011-11-01

270

High-precision \\pbeta decay half-life measurements of proton-rich nuclei for testing the CVC hypothesis  

NASA Astrophysics Data System (ADS)

The experimental study of super-allowed nuclear \\pbeta 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 Vud element of the CKM quark-mixing matrix. Similarly, the study of nuclear mirror \\pbeta decays allows to arrive at the same final quantity Vud. Whereas dedicated studies of 0+ --> 0+ 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 \\pbeta decays. In the present piece of work the half-life measurements performed by the CENBG group of the proton-rich nuclei 42Ti, 38-39Ca, 30-31S and 29P are summarised.

Kurtukian-Nieto, T.

2011-11-01

271

Pick and Place Operation of a Micro Object with High Reliability and Precision Based on Micro Physics Under SEM  

Microsoft Academic Search

The basic strategy for reliable and precise pick-and-place operation is shown based on the actual measurement of adhesion under SEM. Dynamics for pick-and-place operation of a microsphere by a needle-shaped tool is analyzed. A new method of reliable pick and precise place is proposed on the basis of the basic strategy and the dynamics. An experimental system for executing the

Shigeki Saito; Hideki Miyazaki; Tomomasa Sato

1999-01-01

272

High precision measurements of the neutron spin structure in Hall A at Jlab  

SciTech Connect

Conclusions of this presentation are: (1) JLab energy upgrade will offer new exciting opportunities to study the nucleon (spin) structure such as high precision, unexplored phase space, flavor decomposition; (2) Large technological efforts is in progress to optimally exploit these opportunities; (3) HallA will be the first hall to get the new beam, first experiment expected to run in 2014; (4) A1n likely one of the first experiments to take data in the new 12 GeV era; and (5) SIDIS exp. will follow in couple of years.

Annand, R M; Cates, G; Cisbani, E; Franklin, G B; Liyanage, N; Puckett, A; Rosner, G; Wojtsekhowski, B

2012-04-01

273

Precise control of the size and noise of solid-state nanopores using high electric fields.  

PubMed

We present a methodology for preparing silicon nitride nanopores that provides in situ control of size with sub-nanometer precision while simultaneously reducing electrical noise by up to three orders of magnitude through the cyclic application of high electric fields in an aqueous environment. Over 90% of nanopores treated with this technique display desirable noise characteristics and readily exhibit translocation of double-stranded DNA molecules. Furthermore, previously used nanopores with degraded electrical properties can be rejuvenated and used for further single-molecule experiments. PMID:22983670

Beamish, Eric; Kwok, Harold; Tabard-Cossa, Vincent; Godin, Michel

2012-10-12

274

Design and control of a 6-Degree-of-Freedom levitated positioner with high precision  

E-print Network

??????????????????49 2-21 Diagram of the control structure?????????????????????...50 2-22 User interface of the high-precision multidimensional positioning system .....???...51 2-23 Flowcharts of (a) main.c, (b) dsp_command.c, and (c) cint_01.c... and the magnet matrix is determined. A full analysis of the permanent- magnet matrix is covered in the chapter. This chapter also introduced the sensor system and DSP control system. Some critical issues in low-level bus programming such as byte swapping, data...

Hu, Tiejun

2005-08-29

275

Mechanical optimisation of a high-precision fast wire scanner at CERN  

E-print Network

Wire scanners are instruments used to measure the transverse beam prole in particle accelerators by passing a thin wire through the particle beam. To avoid the issues of vacuum leakage through the bellows and wire failure related to current designs of wire scanners, a new concept for a wire scanner has been developed at CERN. This design has all moving parts inside the beam vacuum and has a nominal wire scanning speed of 20 m/s. The demands on the design associated with this together with the high precision requirements create a need for\

Samuelsson, Sebastian; Veness, Raymond

276

High school driver education using peer tutors, direct instruction, and precision teaching.  

PubMed Central

The authors investigated the combined effects of direct instruction and precision teaching by peer tutors in a high school driver education curriculum. Learners (N = 4) included students with intellectual and learning disabilities and students without disabilities. Peer tutoring was associated with immediate increases in correct responding and a simultaneous and rapid deceleration of errors. Three learners passed the written tests in the driver education classroom, obtained driver's licenses, and produced similar or better driving records than students who did not require assistance. This program is being continued and expanded by school personnel without assistance from the authors. PMID:2055802

Bell, K E; Young, K R; Salzberg, C L; West, R P

1991-01-01

277

Experimental needs of high temperature concrete  

SciTech Connect

The needs of experimental data on concrete structures under high temperature, ranging up to about 370/sup 0/C for operating reactor conditions and to about 900/sup 0/C and beyond for hypothetical accident conditions, are described. This information is required to supplement analytical methods which are being implemented into the finite element code TEMP-STRESS to treat reinforced concrete structures. Recommended research ranges from material properties of reinforced/prestressed concrete, direct testing of analytical models used in the computer codes, to investigations of certain aspects of concrete behavior, the phenomenology of which is not well understood. 10 refs.

Chern, J.C.; Marchertas, A.H.

1985-01-01

278

[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

279

High-precision photometry by telescope defocussing. VII. The ultra-short period planet WASP-103  

E-print Network

We present 17 transit light curves of the ultra-short period planetary system WASP-103, a strong candidate for the detection of tidally-induced orbital decay. We use these to establish a high-precision reference epoch for transit timing studies. The time of the reference transit midpoint is now measured to an accuracy of 4.8s, versus 67.4s in the discovery paper, aiding future searches for orbital decay. With the help of published spectroscopic measurements and theoretical stellar models, we determine the physical properties of the system to high precision and present a detailed error budget for these calculations. The planet has a Roche lobe filling factor of 0.58, leading to a significant asphericity; we correct its measured mass and mean density for this phenomenon. A high-resolution Lucky Imaging observation shows no evidence for faint stars close enough to contaminate the point spread function of WASP-103. Our data were obtained in the Bessell $RI$ and the SDSS $griz$ passbands and yield a larger planet ...

Southworth, John; Ciceri, S; Budaj, J; Dominik, M; Jaimes, R Figuera; Haugbolle, T; Jorgensen, U G; Popovas, A; Rabus, M; Rahvar, S; von Essen, C; Schmidt, R W; Wertz, O; Alsubai, K A; Bozza, V; Bramich, D M; Novati, S Calchi; D'Ago, G; Hinse, T C; Henning, Th; Hundertmark, M; Juncher, D; Korhonen, H; Skottfelt, J; Snodgrass, C; Starkey, D; Surdej, J

2014-01-01

280

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

NASA Astrophysics Data System (ADS)

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 world have sensitivity worth on 4-5 orders. It has been developed a new class of fiber-optical sensors (FOS) with light pulse modulation. These sensors have super high threshold sensitivity and wide (up to 10 orders) dynamic range, and can be used as a base for creating of measurement units of physical values as 3D superhigh sensitive precise accelerometers of linear accelerations that is suitable for highest requirements. The principle of operation of the FOS is organically combined with a digital signal processing. It allows decreasing hardware of the accelerometer due to using a usual air-borne or space-borne computer; correcting the influence of natural, design, technological drawbacks of FOS on measured results; neutralising the influence of extraordinary situations available during using of FOS; decreasing the influence of internal and external destabilising factors (as for FOS), such as oscillation of environment temperature, instability of pendulum cycle frequency of sensitive element of the accelerometer etc. We were conducted a quantitative estimation of precise opportunities of analogue FOS in structure of fiber optical measuring devices (FOMD) for elementary FOMD with analogue FOS built on modern element basis of fiber optics (FO), at following assumptions: absolute parameter stability of devices of FOS measuring path; single transmission band of registration path; maximum possible inserted in optical fiber (OF) a radiated power. Even at such idealized assumptions, a calculated value in limit reached minimum inaccuracy of measuring, by analogue FOS, has been ˜ 10-4 %. Substantially accessible values are yet worse on 2-3 order. The reason of poor precise performances of measurers on the basis of analogue FOS is metrologically poor quality of a stream of optical radiation carrying out role of the carrier and receptor of the information. It is a high level of photon noise and a small blanket intensity level. First reason reflects the fact of discreteness of flow of high-energy photons, and it is consequence of second one - smallness, on absolute value, of inserted power into OF from available radiation sources (RS). Works on improvement of FO elements are carrying out. Certainly, it will be created RS allow to insert enough of power into standard OF. But simple increasing of optical flow power in measuring path of FOS will not be able to decide radically the problem of increasing of measuring prices: with raising of power in proportion of square root of its value there is raising a power of photon noises - 1000-times increase of power promises only 30-times increase of measuring precise; insertion into OF more large power (˜ 1 W for standard silicon OF) causes an appearance of non-linear effects in it, which destroying an operating principle of analogue FOS. Thus, it is needed to constatate impossibility of building, at that time, measurers of analogue FOS, concurated with traditional (electrical) measurers on measuring precise. At that all, advantages of FO, as basis of building of FO MD requires to find ways for decision of these problems. Analysis of problem of sensitivity of usual (analogue) FOS has brought us to conclusion about necessity of reviewing of principles of information signal forming in FOS and principles its next electronic processing. For radical increasing of accuracy of measurements with using FOS it is necessary to refuse analogue modulation of optical flow and to transfer to discreet its modulations, entering thus in optical flow new, non-optical, parameters, which will serve as recipients of the information. It allows to save up all advantages of FOS (carrier of in

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

281

High-precision Measurements of piP Elastic Differential Cross Sections in the Second Resonance Region  

E-print Network

Cross sections for pi+-p elastic scattering have been measured to high precision, for beam momenta between 800 and 1240 MeV/c, by the EPECUR Collaboration, using the ITEP proton synchrotron. The data precision allows comparisons of the existing partial-wave analyses (PWA) on a level not possible previously. These comparisons imply that updated PWA are required.

Alekseev, I G; Bordyuzhin, I G; Briscoe, W J; Filimonov, Ye A; Golubev, V V; Gridnev, A B; Kalinkin, D V; Koroleva, L I; Kozlenko, N G; Kozlov, V S; Krivshich, A G; Morozov, B V; Nesterov, V M; Novinsky, D V; Ryltsov, V V; Sadler, M; Shurygin, B M; Strakovsky, I I; Sulimov, A D; Sumachev, V V; Svirida, D N; Tarakanov, V I; Trautman, V Yu; Workman, R L

2014-01-01

282

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. PMID:22778582

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

2012-01-01

283

A high precision position sensor design and its signal processing algorithm for a maglev train.  

PubMed

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. PMID:22778582

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

2012-01-01

284

High-precision work distributions for extreme nonequilibrium processes in large systems  

NASA Astrophysics Data System (ADS)

The distributions of work for strongly nonequilibrium processes are studied using a very general form of a large-deviation approach, which allows one to study distributions down to extremely small probabilities of almost arbitrary quantities of interest for equilibrium, nonequilibrium stationary, and even nonstationary processes. The method is applied to quickly vary the external field in a wide range B =3?0 for a critical (T =2.269) two-dimensional Ising system of size L ×L=128×128. To obtain free-energy differences from the work distributions, they must be studied in ranges where the probabilities are as small as 10-240, which is not possible using direct simulation approaches. By comparison with the exact free energies, which are available for this model for the zero-field case, one sees that the present approach allows one to obtain the free energy with a very high relative precision of 10-4. This works well also for a nonzero field, i.e., for a case where standard umbrella-sampling methods are not efficient to calculate free energies. Furthermore, for the present case it is verified that the resulting distributions of work for forward and backward processes fulfill Crooks theorem with high precision. Finally, the free energy for the Ising magnet as a function of the field strength is obtained.

Hartmann, Alexander K.

2014-05-01

285

Precision-cut liver slices to investigate responsiveness of deep-sea fish to contaminants at high pressure.  

PubMed

While deep-sea fish accumulate high levels of persistent organic pollutants (POPs), the toxicity associated with this contamination remains unknown. Indeed, the recurrent collection of moribund individuals precludes experimental studies to investigate POP effects in this fauna. We show that precision-cut liver slices (PCLS), an in vitro tool commonly used in human and rodent toxicology, can overcome such limitation. This technology was applied to individuals of the deep-sea grenadier Coryphaenoides rupestris directly upon retrieval from 530-m depth in Trondheimsfjord (Norway). PCLS remained viable and functional for 15 h when maintained in an appropriate culture media at 4 °C. This allowed experimental exposure of liver slices to the model POP 3-methylcholanthrene (3-MC; 25 ?M) at levels of hydrostatic pressure mimicking shallow (0.1 megapascal or MPa) and deep-sea (5-15 MPa; representative of 500-1500 m depth) environments. As in shallow water fish, 3-MC induced the transcription of the detoxification enzyme cytochrome P4501A (CYP1A; a biomarker of exposure to POPs). This induction was diminished at elevated pressure, suggesting a limited responsiveness of C. rupestris toward POPs in its native environment. This very first in vitro toxicological investigation on a deep-sea fish opens the route for understanding pollutants effects in this highly exposed fauna. PMID:22900608

Lemaire, Benjamin; Debier, Cathy; Calderon, Pedro Buc; Thomé, Jean Pierre; Stegeman, John; Mork, Jarle; Rees, Jean François

2012-09-18

286

Highly precise and developmentally programmed genome assembly in Paramecium requires ligase IV-dependent end joining.  

PubMed

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. PMID:21533177

Kapusta, Aurélie; Matsuda, Atsushi; Marmignon, Antoine; Ku, Michael; Silve, Aude; Meyer, Eric; Forney, James D; Malinsky, Sophie; Bétermier, Mireille

2011-04-01

287

A demonstration of high precision GPS orbit determination for geodetic applications  

NASA Technical Reports Server (NTRS)

High precision orbit determination of Global Positioning System (GPS) satellites is a key requirement for GPS-based precise geodetic measurements and precise low-earth orbiter tracking, currently under study at JPL. Different strategies for orbit determination have been explored at JPL with data from a 1985 GPS field experiment. The most successful strategy uses multi-day arcs for orbit determination and includes fine tuning of spacecraft solar pressure coefficients and station zenith tropospheric delays using the GPS data. Average rms orbit repeatability values for 5 of the GPS satellites are 1.0, 1.2, and 1.7 m in altitude, cross-track, and down-track componenets when two independent 5-day fits are compared. Orbit predictions up to 24 hours outside the multi-day arcs agree within 4 m of independent solutions obtained with well tracked satellites in the prediction interval. Baseline repeatability improves with multi-day as compared to single-day arc orbit solutions. When tropospheric delay fluctuations are modeled with process noise, significant additional improvement in baseline repeatability is achieved. For a 246-km baseline, with 6-day arc solutions for GPS orbits, baseline repeatability is 2 parts in 100 million (0.4-0.6 cm) for east, north, and length components and 8 parts in 100 million for the vertical component. For 1314 and 1509 km baselines with the same orbits, baseline repeatability is 2 parts in 100 million for the north components (2-3 cm) and 4 parts in 100 million or better for east, length, and vertical components.

Lichten, S. M.; Border, J. S.

1987-01-01

288

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

289

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

NASA Astrophysics Data System (ADS)

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/B4C 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.

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

290

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

291

High-precision photometry by telescope defocussing - VI. WASP-24, WASP-25 and WASP-26  

NASA Astrophysics Data System (ADS)

We present time series photometric observations of 13 transits in the planetary systems WASP-24, WASP-25 and WASP-26. All three systems have orbital obliquity measurements, WASP-24 and WASP-26 have been observed with Spitzer, and WASP-25 was previously comparatively neglected. Our light curves were obtained using the telescope-defocussing method and have scatters of 0.5-1.2 mmag relative to their best-fitting geometric models. We use these data to measure the physical properties and orbital ephemerides of the systems to high precision, finding that our improved measurements are in good agreement with previous studies. High-resolution Lucky Imaging observations of all three targets show no evidence for faint stars close enough to contaminate our photometry. We confirm the eclipsing nature of the star closest to WASP-24 and present the detection of a detached eclipsing binary within 4.25 arcmin of WASP-26.

Southworth, John; Hinse, T. C.; Burgdorf, M.; Calchi Novati, S.; Dominik, M.; Galianni, P.; Gerner, T.; Giannini, E.; Gu, S.-H.; Hundertmark, M.; Jørgensen, U. G.; Juncher, D.; Kerins, E.; Mancini, L.; Rabus, M.; Ricci, D.; Schäfer, S.; Skottfelt, J.; Tregloan-Reed, J.; Wang, X.-B.; Wertz, O.; Alsubai, K. A.; Andersen, J. M.; Bozza, V.; Bramich, D. M.; Browne, P.; Ciceri, S.; D'Ago, G.; Damerdji, Y.; Diehl, C.; Dodds, P.; Elyiv, A.; Fang, X.-S.; Finet, F.; Figuera Jaimes, R.; Hardis, S.; Harpsøe, K.; Jessen-Hansen, J.; Kains, N.; Kjeldsen, H.; Korhonen, H.; Liebig, C.; Lund, M. N.; Lundkvist, M.; Mathiasen, M.; Penny, M. T.; Popovas, A.; Prof., S.; Rahvar, S.; Sahu, K.; Scarpetta, G.; Schmidt, R. W.; Schönebeck, F.; Snodgrass, C.; Street, R. A.; Surdej, J.; Tsapras, Y.; Vilela, C.

2014-10-01

292

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. PMID:22577614

Hartwell, Supaporn Kradtap; Grudpan, Kate

2012-01-01

293

High-precision GPS autonomous platforms for sea ice dynamics and physical oceanography  

NASA Astrophysics Data System (ADS)

Project "Arctic Ocean sea ice and ocean circulation using satellite methods" (SATICE), is the first high-rate, high-precision, continuous GPS positioning experiment on sea ice in the Arctic Ocean. The SATICE systems collect continuous, dual-frequency carrier-phase GPS data while drifting on sea ice. Additional geophysical measurements also collected include ocean water pressure, ocean surface salinity, atmospheric pressure, snow-depth, air-ice-ocean temperature profiles, photographic imagery, and others, enabling sea ice drift, freeboard, weather, ice mass balance, and sea-level height determination. Relatively large volumes of data from each buoy are streamed over a satellite link to a central computer on the Internet in near real time, where they are processed to estimate the time-varying buoy positions. SATICE system obtains continuous GPS data at sub-minute intervals with a positioning precision of a few centimetres in all three dimensions. Although monitoring of sea ice motions goes back to the early days of satellite observations, these autonomous platforms bring out a level of spatio-temporal detail that has never been seen before, especially in the vertical axis. These high-resolution data allows us to address new polar science questions and challenge our present understanding of both sea ice dynamics and Arctic oceanography. We will describe the technology behind this new autonomous platform, which could also be adapted to other applications that require high resolution positioning information with sustained operations and observations in the polar marine environment, and present results pertaining to sea ice dynamics and physical oceanography.

Elosegui, P.; Wilkinson, J.; Olsson, M.; Rodwell, S.; James, A.; Hagan, B.; Hwang, B.; Forsberg, R.; Gerdes, R.; Johannessen, J.; Wadhams, P.; Nettles, M.; Padman, L.

2012-12-01

294

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

PubMed Central

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

2013-01-01

295

Novel fiber Bragg grating fabrication method by high-precision shutter control  

NASA Astrophysics Data System (ADS)

Fiber Bragg grating (FBG) is an important element in many applications including filters and dispersion compensators in fiber communication systems. With recently developed inverse scattering algorithm, FBGs with desired reflection spectrum and/or dispersion properties can now be designed. However, most of these designs require arbitrary grating amplitude and phase control. Previously, fabrication of such FBGs relies on the accurate control of the temporal variation of the intensity pattern using a piezo electric translation stage. The precision of this fabrication method is limited by the noise in the control voltage, which is usually larger than 1%. The distortion in piezo response also affects the performance. In this paper, we develop and demonstrate a novel writing technique for arbitrary FBG fabrication. Our technique is based on a translate-and-write configuration. The incorporation of a precisely controlled shutter allows the apodization and phase of the FBG to be continuously changed at each grating line. The shutter error mainly results from the control signal's timing jitter, which is normally lower than 0.1%. Using this writing technique, we demonstrate a Hamming apodized grating with 20mm length, -22 dB minimum transmission, and < -25 dB reflection side lobe suppression. Furthermore, phase-shift in a grating can be fabricated by a simple delay in the control signal. We also demonstrate FBGs with ?, ?/2, 3?/2 phase-shifts, respectively. Our experimental results are in excellent agreement with theoretical predictions. To show the capability to fabricate a FBG with arbitrary structure, we demonstrate a 35 mm long zero dispersion grating.

Liu, Yisi; Gu, Claire; Pan, J. J.; Dong, Liang; Zhou, Feng Q.

2003-10-01

296

High precision 11B/10B analysis with a simplified MC-ICP-MS  

NASA Astrophysics Data System (ADS)

Boron isotope ratio is a powerful tracer in the fields of geochemistry, biochemistry, and environmental chemistry. One important application of 11B/10B isotope ratio in geochemistry is as an indicator for paleo pH of seawater recorded in marine carbonates in deep-sea sediments. Boron isotope ratios are determined by TIMS or MC-ICP-MS with precisions of better than 0.1 % RSD, but a large inter-lab discrepancy of 0.6 % is still observed for actual carbonate samples (Foster, 2008). Here, we tried to determine B isotope ratio by MC-ICP-MS with a simple and common analytical techniques using a quartz sample introduction system with a PFA nebulizer, and compared to recently developed precise B isotope ratio analysis techniques by TIMS in positive ion detection mode determined as Cs2BO2+ ions with sample amount of <100 ng (Ishikawa and Nagaishi, 2011) and by MC-ICP-MS (Foster, 2008, Louvat et al., 2011). 11B/10B isotope ratios of a 50 ppb B solution dissolved in a HNO3, mannitol, HF-mixed solution were determined against an isotopic reference NIST-SRM 951 with a standard sample bracketing technique in the wet plasma condition. Resultant analytical reproducibility (twice standard deviation) was +/-0.02 % with a consumption of 50 ng B, and the washout time was comparable to that of NH3 gas addition to the introduction system (Foster, 2008). 11B/10B isotope ratios of actual carbonate sample and seawater were determined after simple chemical purification with a common cation exchange resin instead of a boron selective resin. Their relative differences from the standard were consistent with those determined by the positive TIMS within analytical uncertainty. Current potential of MC-ICP-MS for precise B isotopic analysis will be discussed. Foster, G., 2008. Seawater pH, pCO2 and [CO32-] variations in the Caribbean Sea over the last 130kyr: A boron isotope and B/Ca study of planktic foraminifera, Earth Planet. Sci. Lett., 271, 254-266. Ishikawa, T. and Nagaishi, K., 2011. High-precision isotopic analysis of boron by positive thermal ionization mass spectrometry with sample preheating, J. Anal. At. Spectrom., 26, 359-365. Louvat, P., Bouchez, J, and Paris, G., 2011. MC-ICP-MS isotope measurements with direct injection nebulisation (d-DIHEN): Optimisation and application to boron in seawater and carbonate samples., Geostand. Geoanal. Res., 35, 75-88.

Tanimizu, M.; Nagaishi, K.

2012-04-01

297

High Precision Osmium Isotope Measurements Using New Generation Thermal Ionization Mass Spectrometry  

NASA Astrophysics Data System (ADS)

The technique for measuring Os isotopes to high precision (e.g. +/-30-50 ppm on the 186/188 ratio, 2 sigma) via negative thermal ionization mass spectrometry (NTIMS) was established a decade ago at the University of Maryland. Recent technical advances have resulted in the production of a new generation of TIMS that allows isotopic measurements with substantial improvement in accuracy and precision. Because of the improved capability, the new generation TIMS holds great potential to examine a variety of problems in geochemistry and cosmochemistry. Over the past 5 years, I have refined the technique for higher precision measurements of Os isotopes using the Triton TIMS from Thermo Electron. The measurements are made in static mode using 7 Faraday collectors. 70 or more nanograms of Os is loaded onto a Pt filament with barium hydroxide, the latter is an electron emitter that promotes efficient production of Os trioxide. Oxygen is bled into the source at constant pressures. Signal intensities of 120-180 mV 186Os trioxide are generated and measured as negative ions. Oxygen corrections to the raw data are made using the oxygen isotopic composition obtained for 2 ng loads of Re tetroxide measured on the Faraday cups. Multiple runs over the course of 3 years for the same lecture bottle used to bleed in oxygen to the source showed no change in the oxygen isotopic composition. Oxygen corrections are followed by instrumental mass fractionation corrections using 189/188, 192/189, or 192/188 using the exponential law. Both the internal and external precision for standard and unknown data are best when using 192/188, by a factor of 1.4 over 189/188, and 1.8 over 192/189. Replicate runs on 100 ng standard loads of a single filament shows no change in corrected values within external precision for all Os isotopic ratios over a wide range of fractionation, confirming adherence to the exponential law during emission. 39 runs for a standard solution gave +/-14 ppm (2 sigma) on the 186/188 ratio when using 192/188 of 3.083 for normalization. Technique development continues, with a goal of reducing the amount of Os measured to generate these precisions. Applications of this technique to ongoing studies include further examination of 186/188-187/188 variations in mantle-derived materials. Samples studied include Archean and Proteozoic komatiites, abyssal peridotites, plume-derived basalts, and Os-rich alloys from ultramafic portions of ophiolites. The origin of nucleosynthetic Os isotopic anomalies in meteorites, and the cosmic ray exposure effects to the Os isotopic composition of extra-terrestrial materials, are being investigated to evaluate the variation identified in a preliminary set of chondrites using the Triton.

Brandon, A.

2006-12-01

298

Toward High-Precision Astrometry with WFPC2. I. Deriving an Accurate PSF  

E-print Network

The first step toward doing high-precision astrometry is the measurement of individual stars in individual images, a step that is fraught with dangers when the images are undersampled. The key to avoiding systematic positional error in undersampled images is to determine an extremely accurate point-spread function (PSF). We apply the concept of the {\\it effective} PSF, and show that in images that consist of pixels it is the ePSF, rather than the often-used instrumental PSF, that embodies the information from which accurate star positions and magnitudes can be derived. We show how, in a rich star field, one can use the information from dithered exposures to derive an extremely accurate effective PSF by iterating between the PSF itself and the star positions that we measure with it. We also give a simple but effective procedure for representing spatial variations of the HST PSF. With such attention to the PSF, we find that we are able to measure the position of a single reasonably bright star in a single image with a precision of 0.02 pixel (2 mas in WF frames, 1 mas in PC), but with a systematic accuracy better than 0.002 pixel (0.2 mas in WF, 0.1 mas in PC), so that multiple observations can reliably be combined to improve the accuracy by $\\surd N$.

Jay Anderson; Ivan R. King

2000-06-22

299

High-precision correlative fluorescence and electron cryo microscopy using two independent alignment markers?  

PubMed Central

Correlative light and electron microscopy (CLEM) is an emerging technique which combines functional information provided by fluorescence microscopy (FM) with the high-resolution structural information of electron microscopy (EM). So far, correlative cryo microscopy of frozen-hydrated samples has not reached better than micrometre range accuracy. Here, a method is presented that enables the correlation between fluorescently tagged proteins and electron cryo tomography (cryoET) data with nanometre range precision. Specifically, thin areas of vitrified whole cells are examined by correlative fluorescence cryo microscopy (cryoFM) and cryoET. Novel aspects of the presented cryoCLEM workflow not only include the implementation of two independent electron dense fluorescent markers to improve the precision of the alignment, but also the ability of obtaining an estimate of the correlation accuracy for each individual object of interest. The correlative workflow from plunge-freezing to cryoET is detailed step-by-step for the example of locating fluorescence-labelled adenovirus particles trafficking inside a cell. PMID:24262358

Schellenberger, Pascale; Kaufmann, Rainer; Siebert, C. Alistair; Hagen, Christoph; Wodrich, Harald; Grunewald, Kay

2014-01-01

300

Two Fabry-Perot interferometers for high precision wavelength calibration in the near-infrared  

NASA Astrophysics Data System (ADS)

The most frequently used standard light sources for spectroscopic high precision wavelength calibration are hollow cathode lamps. These lamps, however, do not provide homogeneous line distribution and intensities. Particularly in the infrared, the number of useful lines is severely limited and the spectrum is contaminated by lines of the filler gas. With the goal of achieving sub m/s stability in the infrared, as required for detecting earthlike extra-solar planets, we are developing two passively stabilized Fabry-Perot interferometers for the red visible (600-1050nm) and near infrared wavelength regions (900-1350nm). Each of the two interferometers can produce ~15,000 lines of nearly constant brightness. The Fabry-Perot interferometers aim at a RV calibration precision of 10cm/s and are optimized in line shape and spacing for the infrared planet hunting CARMENES spectrograph that is currently being built for the Calar Alto 3.5m telescope. Here we present the first results of our work.

Schäfer, Sebastian; Reiners, Ansgar

2012-09-01

301

Direct high-precision measurement of the magnetic moment of the proton  

E-print Network

The spin-magnetic moment of the proton $\\mu_p$ is a fundamental property of this particle. So far $\\mu_p$ has only been measured indirectly, analysing the spectrum of an atomic hydrogen maser in a magnetic field. Here, we report the direct high-precision measurement of the magnetic moment of a single proton using the double Penning-trap technique. We drive proton-spin quantum jumps by a magnetic radio-frequency field in a Penning trap with a homogeneous magnetic field. The induced spin-transitions are detected in a second trap with a strong superimposed magnetic inhomogeneity. This enables the measurement of the spin-flip probability as a function of the drive frequency. In each measurement the proton's cyclotron frequency is used to determine the magnetic field of the trap. From the normalized resonance curve, we extract the particle's magnetic moment in units of the nuclear magneton $\\mu_p=2.792847350(9)\\mu_N$. This measurement outperforms previous Penning trap measurements in terms of precision by a factor...

Mooser, A; Blaum, K; Franke, K; Kracke, H; Leiteritz, C; Quint, W; Rodegheri, C C; Smorra, C; Walz, J

2014-01-01

302

High precision carbon-interspaced antiscatter grids: Performance testing and moiré pattern analysis  

NASA Astrophysics Data System (ADS)

Recently, we have developed high precision carbon-interspaced antiscatter grids to be suitable for digital radiography (DR) adopting a precise sawing process. For systematic evaluation of the grid performance, we prepared several sample grids having different grid frequencies (4.0-8.5 lines/mm) and grid ratios (5:1-10:1) and established a well-controlled test condition based upon the IEC standard. In this paper, we presented the performance characteristics of the carbon-interspaced grids in terms of the transmission of primary radiation ( Tp), the transmission of scattered radiation ( Ts), the transmission of total radiation ( Tt), contrast improvement factor ( Cif), and Bucky factor ( B). We also described the grid line artifact, known as a moiré pattern, which may be the most critical problem to be solved for the successful grid use in DR. We examined the factors that affect the moiré pattern by integrating the sample grids with an a-Se based flat panel detector having a 139 ?m×139 ?m pixel size.

Lee, S. J.; Cho, H. S.; Oh, J. E.; Choi, S. I.; Cho, H. M.; Park, Y. O.; Hong, D. K.; Lee, M. S.; Yang, Y. J.; Je, U. K.; Kim, D. S.; Lee, H. K.

2011-10-01

303

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. PMID:18955702

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

304

Development of a high-precision ADS-B based conflict alerting system for operations in the airport environment  

E-print Network

The introduction of Automatic Dependent Surveillance - Broadcast (ADS-B) as the future source of aircraft surveillance worldwide provides an opportunity to introduce high-precision airborne conflict alerting systems for ...

Kunzi, Fabrice

2014-01-01

305

DESIGN & EXPERIMENTATION OF HIGH CURRENT DENSITY DC MAGNETOHYDRODYNAMIC (MHD) MICROPUMP  

E-print Network

DESIGN & EXPERIMENTATION OF HIGH CURRENT DENSITY DC MAGNETOHYDRODYNAMIC (MHD) MICROPUMP Nguyen: Design, Fabrication, & Experimentation of DC MHD Micropump OF THE THESIS Design, Fabrication, & Experimentation of DC MHD Micropump by Bao Thanh Nguyen Master of Science

Kassegne, Samuel Kinde

306

A new model of field-aligned currents derived from high-precision satellite magnetic field data  

Microsoft Academic Search

A model of field-aligned currents is derived from high-precision magnetic field measurements from the Ørsted and Magsat satellites, being parameterized by the interplanetary magnetic field strength and direction for summer, winter and equinox. The high-precision data allow the model to be determined directly by a simple 2-D curl technique combined with fitting of spherical harmonic functions. New elements of the

V. O. Papitashvili; F. Christiansen; T. Neubert

2002-01-01

307

Oscillations of high energy neutrinos in matter: Precise formalism and parametric resonance  

E-print Network

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 \\sin^2 2\\theta_m \\Delta V/2\\pi V, where \\theta_m is the mixing angle in matter and \\Delta V is a typical change of the potential over the oscillation length (l \\sim 2\\pi/V). 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 (E > 10 GeV) 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. Future high statistics experiments can provide an unambiguous evidence for this effect.

E. Kh. Akhmedov; M. Maltoni; A. Yu. Smirnov

2005-06-07

308

A High-Precision Multi-Channel TAC and QAC Module for the Neutron Detection Wall  

E-print Network

A single width NIM module that includes eight channels TAC (time-to-amplitude converter) and QAC (charge-to-amplitude converter) is introduced in the paper, which is designed for the large neutron wall detector to measure charge (energy) and time interval simultaneously [1]. The module mainly adopts a high precision gated integral circuit to realize TAC and QAC. The input range of TAC is from 30 ns to 1 us, and the input range of QAC is from 40 pC to 600 pC. The linearity error of TAC is lower than 1.28 %, and the time resolution of TAC is less than 0.871 %. The linearity error of QAC is lower than 0.81 %, and the resolution of QAC is better than 0.936 %.

She Qian-Shun; Su Hong; Qian Yi; Yu Yu-Hong

2014-04-21

309

Classical Cepheids: High-precision Velocimetry, Cluster Membership, and the Effect of Rotation  

NASA Astrophysics Data System (ADS)

Classical Cepheids are crucial calibrators of the extragalactic distance scale. Despite the adjective 'classical' and their use as 'standard candles', many open problems remain and ensure a steady scientific interest in these objects. This thesis has contributed to the understanding of Cepheids via three different topics: (1) an unprecedented observational program dedicated to studying highly precise Doppler measurements (velocimetry), which as has enabled several observational discoveries; (2) a newly-developed astro-statistical method for conducting an all-sky census of Cepheids belonging to Galactic open clusters, which is suitable for the era of large surveys (big data) such as the ESA's Gaia space mission; (3) the first detailed investigation of the effect of rotation on populations of classical Cepheids using Geneva stellar evolution models, which provides an explanation for the 45-year old Cepheid mass discrepancy problem. Last, but not least, I investigated the implications of my work for the extragalactic distance scale.

Anderson, Richard I.

2013-12-01

310

Upgrade of the SPIRAL identification station for high-precision measurements of nuclear ? decay  

NASA Astrophysics Data System (ADS)

The low-energy identification station at SPIRAL (Système de Production d'Ions Radioactifs Accélérés en Ligne) has been upgraded for studying the ? decays of short-lived radioactive isotopes and to perform high-precision half-life and branching-ratio measurements for superallowed Fermi and isospin T=1/2 mirror ? decays. These new capabilities, combined with an existing Paul trap setup for measurements of ?-? angular-correlation coefficients, provide a powerful facility for investigating fundamental properties of the electroweak interaction through nuclear ? decays. A detailed description of the design study, construction, and first results obtained from an in-beam commissioning experiment on the ?+ decays 14 O and 17F are presented.

Grinyer, G. F.; Thomas, J. C.; Blank, B.; Bouzomita, H.; Austin, R. A. E.; Ball, G. C.; Bucaille, F.; Delahaye, P.; Finlay, P.; Frémont, G.; Gibelin, J.; Giovinazzo, J.; Grinyer, J.; Kurtukian-Nieto, T.; Laffoley, A. T.; Leach, K. G.; Lefèvre, A.; Legruel, F.; Lescalié, G.; Perez-Loureiro, D.

2014-03-01

311

TRB3: a 264 channel high precision TDC platform and its applications  

NASA Astrophysics Data System (ADS)

The TRB3 features four FPGA-based TDCs with < 20 ps RMS time precision between two channels and 256+4+4 channels in total. One central FPGA provides flexible trigger functionality and GbE connectivity including powerful slow control. We present recent users' applications of this platform following the COME&KISS principle: successful test beamtimes at CERN (CBM), in Jülich and Mainz with an FPGA-based discriminator board (PaDiWa), a charge-to-width FEE board with high dynamic range, read-out of the n-XYTER ASIC and software for data unpacking and TDC calibration in ROOT. We conclude with an outlook on future developments.

Neiser, A.; Adamczewski-Musch, J.; Hoek, M.; Koenig, W.; Korcyl, G.; Linev, S.; Maier, L.; Michel, J.; Palka, M.; Penschuck, M.; Traxler, M.; U?ur, C.; Zink, A.

2013-12-01

312

A High-Precision Multi-Channel TAC and QAC Module for the Neutron Detection Wall  

E-print Network

A single width NIM module that includes eight channels TAC (time-to-amplitude converter) and QAC (charge-to-amplitude converter) is introduced in the paper, which is designed for the large neutron wall detector to measure charge (energy) and time interval simultaneously [1]. The module mainly adopts a high precision gated integral circuit to realize TAC and QAC. The input range of TAC is from 30 ns to 1 us, and the input range of QAC is from 40 pC to 600 pC. The linearity error of TAC is lower than 1.28 %, and the time resolution of TAC is less than 0.871 %. The linearity error of QAC is lower than 0.81 %, and the resolution of QAC is better than 0.936 %.

Qian-Shun, She; Yi, Qian; Yu-Hong, Yu

2014-01-01

313

LEBIT II: Upgrades and developments for high precision Penning trap mass measurements with rare isotopes  

NASA Astrophysics Data System (ADS)

During the next several years and decades the extension of high-precision Penning trap mass spectrometry measurements to more-exotic isotopes, lying far from the valley of stability will continue to provide significant contributions to nuclear physics. However, such measurements must overcome the challenges of working with isotopes that have low production rates and short lifetimes. At the Low Energy Beam and Ion Trap (LEBIT) facility at the National Superconducting Cyclotron Laboratory, a number of developments have been implemented or are underway to meet these challenges by minimizing rare-isotope preparation and measurement time, maximizing use of available beam time, and increasing sensitivity. These developments and the current status of the LEBIT facility will be discussed.

Redshaw, M.; Bollen, G.; Bustabad, S.; Kwiatkowski, A. A.; Lincoln, D. L.; Novario, S. J.; Ringle, R.; Schwarz, S.; Valverde, A. A.

2013-12-01

314

High precision electric gate for time-of-flight ion mass spectrometers  

NASA Technical Reports Server (NTRS)

A time-of-flight mass spectrometer having a chamber with electrodes to generate an electric field in the chamber and electric gating for allowing ions with a predetermined mass and velocity into the electric field. The design uses a row of very thin parallel aligned wires that are pulsed in sequence so the ion can pass through the gap of two parallel plates, which are biased to prevent passage of the ion. This design by itself can provide a high mass resolution capability and a very precise start pulse for an ion mass spectrometer. Furthermore, the ion will only pass through the chamber if it is within a wire diameter of the first wire when it is pulsed and has the right speed so it is near all other wires when they are pulsed.

Sittler, Edward C. (Inventor)

2011-01-01

315

Influence of sulfur-bearing polyatomic species on high precision measurements of Cu isotopic composition  

USGS Publications Warehouse

An increased interest in high precision Cu isotope ratio measurements using multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) has developed recently for various natural geologic systems and environmental applications, these typically contain high concentrations of sulfur, particularly in the form of sulfate (SO42-) and sulfide (S). For example, Cu, Fe, and Zn concentrations in acid mine drainage (AMD) can range from 100??g/L to greater than 50mg/L with sulfur species concentrations reaching greater than 1000mg/L. Routine separation of Cu, Fe and Zn from AMD, Cu-sulfide minerals and other geological matrices usually incorporates single anion exchange resin column chromatography for metal separation. During chromatographic separation, variable breakthrough of SO42- during anion exchange resin column chromatography into the Cu fractions was observed as a function of the initial sulfur to Cu ratio, column properties, and the sample matrix. SO42- present in the Cu fraction can form a polyatomic 32S-14N-16O-1H species causing a direct mass interference with 63Cu and producing artificially light ??65Cu values. Here we report the extent of the mass interference caused by SO42- breakthrough when measuring ??65Cu on natural samples and NIST SRM 976 Cu isotope spiked with SO42- after both single anion column chromatography and double anion column chromatography. A set of five 100??g/L Cu SRM 976 samples spiked with 500mg/L SO42- resulted in an average ??65Cu of -3.50?????5.42??? following single anion column separation with variable SO42- breakthrough but an average concentration of 770??g/L. Following double anion column separation, the average SO42-concentration of 13??g/L resulted in better precision and accuracy for the measured ??65Cu value of 0.01?????0.02??? relative to the expected 0??? for SRM 976. We conclude that attention to SO42- breakthrough on sulfur-rich samples is necessary for accurate and precise measurements of ??65Cu and may require the use of a double ion exchange column procedure. ?? 2010.

Pribil, M.J.; Wanty, R.B.; Ridley, W.I.; Borrok, D.M.

2010-01-01

316

High precision determination of the atmospheric parameters and abundances of the COROT main targets  

E-print Network

One of the main goals of the COROT mission is to get precise photometric observations of selected bright stars in order to allow the modelling of their interior through asteroseismology. However, in order to interpret the asteroseismological data, the effective temperature, surface gravity, and chemical composition of the stars must be known with sufficient accuracy. To carry out this task, we have developed a spectroscopic method called APASS (Atmospheric Parameters and Abundances from Synthetic Spectra) which allows precise analysis of stars with a moderate to high rotational velocity, which is the case for most primary COROT targets. Our method is based on synthetic spectra and works differentially with respect to the Sun. Using high signal-to-noise spectra and the APASS method, we determined the atmospheric parameters and chemical abundances of 13 primary COROT targets. Our results agree well with those obtained by Bruntt using his software VWA and with those obtained with the software TEMPLOGG. However, in both cases, our error bars are significantly smaller than those of other methods. Our effective temperatures are also in excellent agreement with those obtained with the IR photometry method. For five stars with relatively low rotational velocity, we also performed an analysis with a classical equivalent-width method to test agreement with APASS results. We show that equivalent-width measurements by Gaussian or Voigt profile-fitting are sensitive to the rotational broadening, leading to systematic errors whenever the projected rotation velocity is non-negligible. The APASS method appears superior in all cases and should thus be preferred.

M. Gillon; P. Magain

2005-11-03

317

A high precision micropositioner with five degrees of freedom based on an electromagnetic driving principle  

NASA Astrophysics Data System (ADS)

A five degrees of freedom high precision micropositioner based on spring suspension and electromagnetic driving has been designed, constructed, and tested. The device consists of two parts: a moving part and a stationary part. The moving part, named as ``motor'', is formed with a rigid frame and three groups of coils fixed on it. The stationary part of the device, called ``stator'', includes a chassis and twelve U-shaped magnetic ``shoes''. The motor is attached to the stator with flat springs whose linear suspension allows it to move in all dimensions except the rotation around z axis. The coils have been laid out in such a way that fractions of them pass through the air gaps between the facing magnets in the magnetic shoes. When electrical currents are supplied to the coils, the resulting Lorenz forces drive the motor to move in the five degrees of freedom allowed by the spring suspension. Since the system is inherently stable and there is no mechanical friction, the open-loop resolutions of the device are found to be limited only by that of the 12-bit D/A board used. A closed-loop translation resolution of 0.3 ?m has been achieved over a working space of 180 ?m by 180 ?m by 680 ?m. A closed-loop rotation resolution of 2.73×10-6 rad has been achieved over a working space of 1.38×10-3 rad. Potentially the device can be used for high precision microprobing and testing, cellular biology, microsurgery, and testing of micromechanical devices in the fast developing MEMS area.

Wang, Wanjun; He, Tian

1996-01-01

318

Correlated cryo-fluorescence and cryo-electron microscopy with high spatial precision and improved sensitivity.  

PubMed

Performing fluorescence microscopy and electron microscopy on the same sample allows fluorescent signals to be used to identify and locate features of interest for subsequent imaging by electron microscopy. To carry out such correlative microscopy on vitrified samples appropriate for structural cryo-electron microscopy it is necessary to perform fluorescence microscopy at liquid-nitrogen temperatures. Here we describe an adaptation of a cryo-light microscopy stage to permit use of high-numerical aperture objectives. This allows high-sensitivity and high-resolution fluorescence microscopy of vitrified samples. We describe and apply a correlative cryo-fluorescence and cryo-electron microscopy workflow together with a fiducial bead-based image correlation procedure. This procedure allows us to locate fluorescent bacteriophages in cryo-electron microscopy images with an accuracy on the order of 50 nm, based on their fluorescent signal. It will allow the user to precisely and unambiguously identify and locate objects and events for subsequent high-resolution structural study, based on fluorescent signals. PMID:24275379

Schorb, Martin; Briggs, John A G

2014-08-01

319

Development of the High Precision Telescope on the RISING-2 micro satellite  

NASA Astrophysics Data System (ADS)

We developed the High Precision Telescope (HPT) which will be installed on a micro satellite, RISING-2. The RISING-2 satellite is the succession mission of the RISING satellite, which was successfully launched on 23 January 2009. These two 50 kg class satellites have been developed in-house by the universities. The HPT uses a zero thermal expansion pore-free ceramics (ZPF) mirror for the optical system, a liquid crystal tunable filter (LCTF) for the spectrometry, and high-sensitivity charge coupled device (CCD) cameras for the imaging. The HPT is a highly-functional multi-purpose space telescope that can be widely used for near-IR observations of the Earth and planets, such as the Jupiter and Venus. One of the applications is a high-resolution observation of thunderclouds in the Earth. Detailed information on a thundercloud structure will help to issue early-warnings of floods caused by torrential rains. The thundercloud structure observations from space are useful especially in areas without a weather radar network. The HPT will give a technology demonstration of the multi-spectral telescopic imaging for global remote sensing of weather disasters, land-use, ocean development, etc.

Kurihara, Junichi; Takahashi, Yukihiro

320

Novel high-speed 3-DOF linear direct drive operating with submicron precision  

NASA Astrophysics Data System (ADS)

Developments in microelectronics, micromechanics and microelectromechanical systems require significant improvements in manufacturing tools for mass productions. Especially the assembling tools have to become feaster and more precise. Many assembly devices use XY stages driven by DC servomotors with ball screws or parallel structures; others use linear drives with traditional ball bearings. Only a few devices use linear drives together with air bearings, but always together with an angular guide for X and Y direction. The novel approach present in this paper is based on linear drives together with a planar air bearing. In contrast to other stages, it does not need any angular guide. This reduces the moved mass and leads to higher accelerations. It consists of an arrangement of four identical moving-coils attached to a slide, which is suspended by a planar air bearing. This new configuration allows a workspace of 60 X 60 mm2 and an acceleration exceeding 10 g1 with a resolution better than 100 nm. This paper gives an overview of the system, describes the design of the moving coils and shows first experimental result of the controller.

Sprenger, Bernhard; Siegwart, Roland Y.

1998-01-01

321

High-precision molecular dynamics simulation of UO2-PuO2: Anion self-diffusion in UO2  

E-print Network

Our series of articles is devoted to high-precision molecular dynamics simulation of mixed actinide-oxide (MOX) fuel in the approximation of rigid ions and pair interactions (RIPI) using high-performance graphics processors (GPU). In this article we study self-diffusion mechanisms of oxygen anions in uranium dioxide (UO2) with the ten recent and widely used sets of interatomic pair potentials (SPP) under periodic (PBC) and isolated (IBC) boundary conditions. Wide range of measured diffusion coefficients (from 10^-3 cm^2/s at melting point down to 10^-11 cm2/s at 1400 K) made possible a direct comparison (without extrapolation) of the simulation results with the experimental data, which have been known only at low temperatures (T < 1500 K). A highly detailed (with the temperature step of 1 K) calculation of the diffusion coefficient allowed us to plot temperature dependences of the diffusion activation energy and its derivative, both of which show a wide (~1000 K) superionic transition region confirming the...

Potashnikov, S I; Nekrasov, K A; Kupryazhkin, A Ya

2012-01-01

322

HPMSS(High Precision Magnetic Survey System) and InterRidge  

NASA Astrophysics Data System (ADS)

From the beginning of 1990s to the beginning of 2000s, the Japanese group of IntreRidge conducted many cruises for three component magnetic survey using Shipboard Three Component Magnetometer (STCM) and Deep Towed Three Component Magnetometer (DTCM) in the world wide oceans. We have been developing HPMSS during this time with support of Dr.Tamaki(the late representative of InterRidge Japan) who understood the advantages of three component geomagnetic anomalies (TCGA). TCGA measured by STCM determines the direction of geomagnetic anomaly lineations precisely at every point where TCGA were observed, which playes the important role in magnetic anomaly lineation analysis. Even in the beginning of 2000s, almost all marine magnetic scientists believed that the total intensity anomly (TIA) is the better data than TCGA for analysis because the scalar magnetometers (e.g. proton precession magnetometer) have the better accuracy than any other magnetometers (e.g.flux gate magnetometer (FGM)). We employed the high accrate gyroscope (e.g.ring lase gyroscope (RLG)/optical fiber gyroscope (OFG)) to improve the accuracy of STCM/DTCM equipped with FGM. Moreover we employed accurate and precise FGM which was selected among the market. Finally we developed the new magnetic survey system with high precision usable as airborn, shipboard and dee-ptowed magnetometers which we call HPMSS(High Precision Magnetic Survey System). As an optional equipment, we use LAN to communicate between a data aquisiitin part and a data logging part, and GPS for a position fix. For the deep-towed survey, we use the acoustic position fix (super short base line method) and the acoustic communication to monitor the DTCM status. First we used HPMSS to obtain the magnetization structure of the volcanic island, Aogashima located 300km south of Tokyo using a hellcopter in 2006 and 2009. Next we used HPMSS installed in DTCM in 2010,2011 and 2012 using R/V Bosei-maru belonging to Tokai University. Also we used HPMSS installed in AUV (automonous undersea vehicle), belonging to JAMSTEC in 2009,2010 and 2011. We have been emphasizing the importnace of TCGA compared to TIA because TIA does not obey the Laplace equation which means TIA is not harmonic, then we cannot apply the Fourier analysis on TIA. We will show the structure of three component magnetization of the mineral deposit in the volcanic thermal area in Izu-Ogasawara island Arc, called Hakurei Deposit. TCGA of DTCM and AUV survey data were used and the depth section and the vertical section of three components of magnetization of Hakurei Deposit area will be presented. We emphasize that reliable 3D structure of three component of magnetization was obtained from TCGA using HPMSS as the result of deep support of InterRidge Japan, especially deep support of Dr. Tamaki.

Isezaki, N.; Sayanagi, K.

2012-12-01

323

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

324

QCD Precision Measurements and Structure Function Extraction at a High Statistics, High Energy Neutrino Scattering Experiment: NuSOnG  

E-print Network

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.

T. Adams; P. Batra; L. Bugel; L. Camilleri; J. M. Conrad; A. de Gouvêa; P. H. Fisher; J. A. Formaggio; J. Jenkins; G. Karagiorgi; T. R. Kobilarcik; S. Kopp; G. Kyle; W. A. Loinaz; D. A. Mason; R. Milner; R. Moore; J. G. Morfín; M. Nakamura; D. Naples; P. Nienaber; F. I. Olness; J. F. Owens; S. F. Pate; A. Pronin; W. G. Seligman; M. H. Shaevitz; H. Schellman; I. Schienbein; M. J. Syphers; T. M. P. Tait; T. Takeuchi; C. Y. Tan; R. G. Van de Water; R. K. Yamamoto; J. Y. Yu

2009-06-19

325

High-Precision Measurement of the 19Ne Half-Life and Implications for Right-Handed Weak Currents  

E-print Network

We report a precise determination of the 19Ne half-life to be $T_{1/2} = 17.262 \\pm 0.007$ s. This result disagrees with the most recent precision measurements and is important for placing bounds on predicted right-handed interactions that are absent in the current Standard Model. We are able to identify and disentangle two competing systematic effects that influence the accuracy of such measurements. Our findings prompt a reassessment of results from previous high-precision lifetime measurements that used similar equipment and methods.

S. Triambak; P. Finlay; C. S. Sumithrarachchi; G. Hackman; G. C. Ball; P. E. Garrett; C. E. Svensson; D. S. Cross; A. B. Garnsworthy; R. Kshetri; J. N. Orce; M. R. Pearson; E. R. Tardiff; H. Al-Falou; R. A. E. Austin; R. Churchman; M. K. Djongolov; R. D'Entremont; C. Kierans; L. Milovanovic; S. O'Hagan; S. Reeve; S. K. L. Sjue; S. J. Williams

2012-06-25

326

A novel algorithm combining oversampling and digital lock-in amplifier of high speed and precision.  

PubMed

Because of a large amount of arithmetic in the standard digital lock-in detection, a high performance processor is needed to implement the algorithm in real time. This paper presents a novel algorithm that integrates oversampling and high-speed lock-in detection. The algorithm sets the sampling frequency as a whole-number multiple of four of the input signal frequency, and then uses the common downsampling technology to lower the sampling frequency to four times of the input signal frequency. It could effectively remove the noise interference and improve the detection accuracy. After that the phase sensitive detector is implemented. It simply does the addition and subtraction on four points in the period of same phase and replaces almost all the multiplication operations to speed up digital lock-in detection calculation substantially. Furthermore, the correction factor is introduced to improve the calculation accuracy of the amplitude, and an error caused by the algorithm in theory can be eliminated completely. The results of the simulation and actual experiments show that the novel algorithm combining digital lock-in detection and oversampling not only has the high precision, but also has the unprecedented speed. In our work, the new algorithm is suitable for the real-time weak signal detection in the general microprocessor not just digital signal processor. PMID:21974618

Li, Gang; Zhou, Mei; He, Feng; Lin, Ling

2011-09-01

327

New technology enables high precision multislit collimators for microbeam radiation therapy  

SciTech Connect

During the past decade microbeam radiation therapy has evolved from preclinical studies to a stage in which clinical trials can be planned, using spatially fractionated, highly collimated and high intensity beams like those generated at the x-ray ID17 beamline of the European Synchrotron Radiation Facility. The production of such microbeams typically between 25 and 100 {mu}m full width at half maximum (FWHM) values and 100-400 {mu}m center-to-center (c-t-c) spacings requires a multislit collimator either with fixed or adjustable microbeam width. The mechanical regularity of such devices is the most important property required to produce an array of identical microbeams. That ensures treatment reproducibility and reliable use of Monte Carlo-based treatment planning systems. New high precision wire cutting techniques allow the fabrication of these collimators made of tungsten carbide. We present a variable slit width collimator as well as a single slit device with a fixed setting of 50 {mu}m FWHM and 400 {mu}m c-t-c, both able to cover irradiation fields of 50 mm width, deemed to meet clinical requirements. Important improvements have reduced the standard deviation of 5.5 {mu}m to less than 1 {mu}m for a nominal FWHM value of 25 {mu}m. The specifications of both devices, the methods used to measure these characteristics, and the results are presented.

Braeuer-Krisch, E.; Requardt, H.; Brochard, T.; Berruyer, G.; Renier, M.; Bravin, A. [European Synchrotron Radiation Facility, B.P. 220, 38043 Grenoble (France); Laissue, J. A. [Institute of Pathology, University of Bern, Murtenstrasse 31, 3010 Bern (Switzerland)

2009-07-15

328

THE APPLICATION OF MULTIVIEW METHODS FOR HIGH-PRECISION ASTROMETRIC SPACE VLBI AT LOW FREQUENCIES  

SciTech Connect

High-precision astrometric space very long baseline interferometry (S-VLBI) at the low end of the conventional frequency range, i.e., 20 cm, is a requirement for a number of high-priority science goals. These are headlined by obtaining trigonometric parallax distances to pulsars in pulsar-black hole pairs and OH masers anywhere in the Milky Way and the Magellanic Clouds. We propose a solution for the most difficult technical problems in S-VLBI by the MultiView approach where multiple sources, separated by several degrees on the sky, are observed simultaneously. We simulated a number of challenging S-VLBI configurations, with orbit errors up to 8 m in size and with ionospheric atmospheres consistent with poor conditions. In these simulations we performed MultiView analysis to achieve the required science goals. This approach removes the need for beam switching requiring a Control Moment Gyro, and the space and ground infrastructure required for high-quality orbit reconstruction of a space-based radio telescope. This will dramatically reduce the complexity of S-VLBI missions which implement the phase-referencing technique.

Dodson, R.; Rioja, M.; Imai, H. [International Centre for Radio Astronomy Research, M468, University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009 (Australia); Asaki, Y. [Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Chuou, Sagamihara, Kanagawa 252-5210 (Japan); Hong, X.-Y.; Shen, Z., E-mail: richard.dodson@icrar.org [Shanghai Astronomical Observatory, CAS, 200030 Shanghai (China)

2013-06-15

329

Ultra-high-precision alignment technology for lens manufacturing used for high-end optics  

NASA Astrophysics Data System (ADS)

This article describes the progress in the area of modern centration technology by using digital image processing. This work is motivated by the continuously increasing demand for high-end optics. During the last years the surface lens quality has been continuously improved. Today the image quality is more determined by the manufacturing tolerances for the mechanical interface which is responsible for decenter and tilt of the lenses respectively the subgroups. Some of the aberrations are directly linked to the decenter of the lenses, Coma for example. Hence it is necessary to realize the subgroups with tolerances below lpm. To determine the decenter of a lens an auto collimation telescope is used to image the reflex of the lens surfaces onto a detector, commonly a half covert photodiode. Rotating the lens generates a sinusoidal signal, which is evaluated by a lock-in amplifier to drive two actuators to adjust the alignment chuck. Typical internal reflections caused by stray light for example disturb the current procedure in such a way that it is impossible to get a stable alignment process. Digital image processing allows us to fix these problems with image recognition. We will demonstrate how a modified auto collimation telescope in combination with the developed software algorithms made the manufacturing process more accurate, faster and useable for a broad spectrum of lenses. It has been proofed by some thousand diverse lenses that with these new technique subgroups can be centered within 0.25?m.

Schiffner, Sebastian; Sure, Thomas

2013-09-01

330

COROT-high-precision stellar photometry on a low Earth orbit: solutions to minimize environmental perturbations  

NASA Astrophysics Data System (ADS)

The COROT small satellite project is a space mission dedicated to stellar seismology and search for telluric extra-solar planets. For the two programs a very high photometric precision is needed. The COROT seismology program will measure periodic variations with amplitude of 2.10-6 of the photon flux emitted by bright stars. COROT will also be able to detect the presence of exoplanets when they pass between the satellite and their parent star. Modifying both the integration time and the focus conditions, it allows to detect photons flux variations about 7.10-4 in one hour integration, compatible with an occultation detection on a very large number of stars (magnitude between 12 and 15.5). Between 10 and 40 telluric planets in the "habitable zone" and several hundreds of hot Jupiters should be detected depending on hypotheses about planets existence. To reach the required performances a stringent instrument stability is necessary. The satellite Preliminary Design Review will be held in November 2002 while the instrument is already in development phase for a delivery of the flight model in 2004. The launch is scheduled late 2005, by the first SOYUZ launcher to fly from the Guyana Space Center. The project activities are currently focused on the instrument and system engineering. Straylight rejection, pointing, thermal stability are the main critical points of the mission, on a LEO at 826 kms, for which cost-effective compromises have been found to 1mit their effects. This paper recalls the scientific program s, the main characteristics of the mission, describes the impact of the three main perturbators on the photometric precision and the technical solutions which reduce their contribution at an acceptable level.

Auvergne, Michel; Boisnard, Laurent; Buey, Jean-Tristan M.; Epstein, Gerard; Hustaix, Herve; Jouret, Martine; Levacher, Patrick; Berrivin, Stephane; Baglin, Annie

2003-02-01

331

Induced ? rhythms track the content and quality of visual working memory representations with high temporal precision.  

PubMed

Past work has suggested that neuronal oscillations coordinate the cellular assemblies that represent items in working memory (WM). In line with this hypothesis, we show that the spatial distribution of power in the alpha frequency band (8-12 Hz) can be used to decode the content and quality of the representations stored in visual WM. We acquired EEG data during an orientation WM task, and used a forward encoding model of orientation selectivity to reconstruct orientation-specific response profiles (termed channel tuning functions, or CTFs) that tracked the orientation of the memorandum during both encoding and delay periods of the trial. Critically, these EEG-based CTFs were robust predictors of both between- and within-subject differences in mnemonic precision, showing that EEG-based CTFs provide a sensitive measure of the quality of sensory population codes. Experiments 2 and 3 established that these EEG-based CTFs are contingent on the voluntary storage goals of the observer. When observers were given a postsample cue to store or drop the memorandum, the resulting CTF was sustained in the "store" condition and rapidly eliminated following the "drop" cue. When observers were instructed to store one of two simultaneously presented stimuli, only the stored item was represented in a sustained fashion throughout the delay period. These findings suggest that the oscillatory activity in the alpha frequency band plays a central role in the active storage of information in visual WM, and demonstrate a powerful approach for tracking the precision of on-line memories with high temporal resolution. PMID:24872563

Anderson, David E; Serences, John T; Vogel, Edward K; Awh, Edward

2014-05-28

332

High Precision CTE-Measurement of SiC-100 for Cryogenic Space-Telescopes  

E-print Network

We present the results of high precision measurements of the thermal expansion of the sintered SiC, SiC-100, intended for use in cryogenic space-telescopes, in which minimization of thermal deformation of the mirror is critical and precise information of the thermal expansion is needed for the telescope design. The temperature range of the measurements extends from room temperature down to $\\sim$ 10 K. Three samples, #1, #2, and #3 were manufactured from blocks of SiC produced in different lots. The thermal expansion of the samples was measured with a cryogenic dilatometer, consisting of a laser interferometer, a cryostat, and a mechanical cooler. The typical thermal expansion curve is presented using the 8th order polynomial of the temperature. For the three samples, the coefficients of thermal expansion (CTE), $\\bar{\\alpha}_{#1}$, $\\bar{\\alpha}_{#2}$, and $\\bar{\\alpha}_{#3}$ were derived for temperatures between 293 K and 10 K. The average and the dispersion (1 $\\sigma$ rms) of these three CTEs are 0.816 and 0.002 ($\\times 10^{-6}$/K), respectively. No significant difference was detected in the CTE of the three samples from the different lots. Neither inhomogeneity nor anisotropy of the CTE was observed. Based on the obtained CTE dispersion, we performed an finite-element-method (FEM) analysis of the thermal deformation of a 3.5 m diameter cryogenic mirror made of six SiC-100 segments. It was shown that the present CTE measurement has a sufficient accuracy well enough for the design of the 3.5 m cryogenic infrared telescope mission, the Space Infrared telescope for Cosmology and Astrophysics (SPICA).

K. Enya; N. Yamada; T. Onaka; T. Nakagawa; H. Kaneda; M. Hirabayashi; Y. Toulemont; D. Castel; Y. Kanai; N. Fujishiro

2007-04-12

333

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

334

The ASTROID Simulator Software Package: Realistic Modelling of High-Precision High-Cadence Space-Based Imaging  

E-print Network

The preparation of a space-mission that carries out any kind of imaging to detect high-precision low-amplitude variability of its targets requires a robust model for the expected performance of its instruments. This model cannot be derived from simple addition of noise properties due to the complex interaction between the various noise sources. While it is not feasible to build and test a prototype of the imaging device on-ground, realistic numerical simulations in the form of an end-to-end simulator can be used to model the noise propagation in the observations. These simulations not only allow studying the performance of the instrument, its noise source response and its data quality, but also the instrument design verification for different types of configurations, the observing strategy and the scientific feasibility of an observing proposal. In this way, a complete description and assessment of the objectives to expect from the mission can be derived. We present a high-precision simulation software packag...

Marcos-Arenal, P; De Ridder, J; Huygen, R; Aerts, C

2014-01-01

335

Mid-infrared frequency comb for broadband high precision and sensitivity molecular spectroscopy.  

PubMed

We report on the experimental demonstration of the metrological and spectroscopic performances of a mid-infrared comb generated by a nonlinear downconversion process from a Ti:sapphire-based near-infrared comb. A quantum cascade laser at 4330 nm was phase-locked to a single tooth of this mid-infrared comb and its frequency-noise power spectral density was measured. The mid-infrared comb itself was also used as a multifrequency highly coherent source to perform ambient air direct comb spectroscopy with the Vernier technique, by demultiplexing it with a high-finesse Fabry-Perot cavity. PMID:25166071

Galli, I; Bartalini, S; Cancio, P; Cappelli, F; Giusfredi, G; Mazzotti, D; Akikusa, N; Yamanishi, M; De Natale, P

2014-09-01

336

Regional Heterogeneity Within the Icelandic Mantle Revealed Through High-Precision Pb Isotope Data  

NASA Astrophysics Data System (ADS)

We report high-precision Pb-isotope data for > 120 neovolcanic lavas from Iceland that were analysed on an Axiom double focusing MC-ICP-MS, using a 207Pb-204Pb double spike to correct for instrumental mass bias. The external reproducibility of Pb isotope ratios determined for the standard SRM981 was +/-100 ppm (DS corrected) and replicate analyses of samples have a similar reproducibility. The study encompasses all the neovolcanic rift and off-rift zones, including alkalic and tholeiitic picrites, basalts and rhyolites. We observe a similar range in 206Pb/204Pb to published conventional TIMS results, but with a significant reduction in the 207Pb/204Pb and 208Pb/204Pb variation at a given 206Pb/204Pb value. Some scatter in 207Pb/204Pb still remains, which probably reflects real small-scale heterogeneities. The anomalously high 207Pb/204Pb values previously reported for Oraefajokull are confirmed here. For geographically restricted areas such as Reykjanes, Theistareykir and each of the Icelandic alkaline centres, we observe tight coherent linear data arrays in 207Pb/204Pb and 208Pb/204Pb vs 206Pb/204Pb that are interpreted as binary mixing lines, although each array is offset from the others such that more than four end-members are required. One of the most striking features of these new data is the offset in ?8/4Pb between lavas from localities NE and SW of the assumed plume axis. This offset is very similar to that observed between lavas from the two volcanic trends in Hawaii. In Iceland, lavas from each region fall on broad distinct arrays with their most radiogenic compositions represented by alkaline lavas from Snaefell-Oraefajokull (NE) and Eyjafjoll-Torfajokull, respectively. Furthermore, both regions seem to link up compositionally (including Sr, Nd and He isotopes) as well as physically with the adjacent Kolbeinsey and Reykjanes ridges. There is a crude negative correlation between 3He/4He and both ?7/4Pb and ?8/4Pb, opposite to that observed for Hawaiian lavas. However, at this stage the extreme He-Pb isotopic composition of alkaline lavas may bias our observations. In conclusion, our extensive high precision Pb isotopic data set resolves local mixing relationships, regional chemical provinces and correlations with 3He/4He, and demonstrates that the Pb isotope variations cannot simply be explained in terms of just two or three end-member components.

Breddam, K.; Baker, J. A.; Peate, D. W.; Skovgaard, A. C.; Stecher, O.; Waight, T. E.; Prestvik, T.; Jonasson, K.

2002-12-01

337

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

338

High precision during food recruitment of experienced (reactivated) foragers in the stingless bee Scaptotrigona mexicana (Apidae, Meliponini)  

NASA Astrophysics Data System (ADS)

Several studies have examined the existence of recruitment communication mechanisms in stingless bees. However, the spatial accuracy of location-specific recruitment has not been examined. Moreover, the location-specific recruitment of reactivated foragers, i.e., foragers that have previously experienced the same food source at a different location and time, has not been explicitly examined. However, such foragers may also play a significant role in colony foraging, particularly in small colonies. Here we report that reactivated Scaptotrigona mexicana foragers can recruit with high precision to a specific food location. The recruitment precision of reactivated foragers was evaluated by placing control feeders to the left and the right of the training feeder (direction-precision tests) and between the nest and the training feeder and beyond it (distance-precision tests). Reactivated foragers arrived at the correct location with high precision: 98.44% arrived at the training feeder in the direction trials (five-feeder fan-shaped array, accuracy of at least +/-6° of azimuth at 50 m from the nest), and 88.62% arrived at the training feeder in the distance trials (five-feeder linear array, accuracy of at least +/-5 m or +/-10% at 50 m from the nest). Thus, S. mexicana reactivated foragers can find the indicated food source at a specific distance and direction with high precision, higher than that shown by honeybees, Apis mellifera, which do not communicate food location at such close distances to the nest.

Sánchez, Daniel; Nieh, James C.; Hénaut, Yann; Cruz, Leopoldo; Vandame, Rémy

339

High-precision topography measurement through accurate in-focus plane detection with hybrid digital holographic microscope and white light interferometer module.  

PubMed

High-precision topography measurement of micro-objects using interferometric and holographic techniques can be realized provided that the in-focus plane of an imaging system is very accurately determined. Therefore, in this paper we propose an accurate technique for in-focus plane determination, which is based on coherent and incoherent light. The proposed method consists of two major steps. First, a calibration of the imaging system with an amplitude object is performed with a common autofocusing method using coherent illumination, which allows for accurate localization of the in-focus plane position. In the second step, the position of the detected in-focus plane with respect to the imaging system is measured with white light interferometry. The obtained distance is used to accurately adjust a sample with the precision required for the measurement. The experimental validation of the proposed method is given for measurement of high-numerical-aperture microlenses with subwavelength accuracy. PMID:24787417

Li?ewski, Kamil; Tomczewski, S?awomir; Kozacki, Tomasz; Kostencka, Julianna

2014-04-10

340

Optomechanical design of a high-precision detector robot arm system for x-ray nano-diffraction with x-ray nanoprobe  

NASA Astrophysics Data System (ADS)

Collaboration between Argonne National Laboratory and Brookhaven National Laboratory has created a design for the high-precision detector robot arm system that will be used in the x-ray nano-diffraction experimental station at the Hard X-ray Nanoprobe (HXN) beamline for the NSLS-II project. The robot arm system is designed for positioning and manipulating an x-ray detector in three-dimensional space for nano-diffraction data acquisition with the HXN x-ray microscope. It consists of the following major component groups: a granite base with air-bearing support, a 2-D horizontal base stage, a vertical axis goniometer, a 2-D vertical plane robot arm, a 3-D fast scanning stages group, and a 2-D x-ray pixel detector. The design specifications and unique optomechanical structure of this novel high-precision detector robot arm system will be presented in this paper.

Shu, D.; Kalbfleisch, S.; Kearney, S.; Anton, J.; Chu, Y. S.

2014-03-01

341

High-precision B(E2) measurements of semi-magic 58,60,62,64Ni by Coulomb excitation  

SciTech Connect

High-precision reduced electric-quadrupole transition probabilities B(E2) have been measured from single-step Coulomb excitation of semi-magic 58,60,62,64 Ni (Z = 28) beams at 1.8 MeV per nucleon on a natural carbon target. The energy loss of the nickel beams through the carbon target were directly measured with a zero-degree Bragg detector and the absolute B(E2) values were normalized by Rutherford scattering. The B(E2) values disagree with recent lifetime studies that employed the Doppler-shift attenuation method. The present high-precision B(E2) values reveal an asymmetry about 62 Ni, midshell between N = 28 and 40, with larger values towards 56 Ni (Z = N = 28). The experimental B(E2) values are compared with shell-model calculations in the full pf model space and the results indicate a soft 56 Ni core.

Allmond, James M [ORNL; Brown, Alex [National Superconducting Cyclotron Laboratory (NSCL), Michigan State University; Stuchbery, Andrew E [ORNL; Galindo-Uribarri, Alfredo {nmn} [ORNL; Padilla-Rodal, Elizabeth [Universidad Nacional Autonoma de Mexico (UNAM); Radford, David C [ORNL; Batchelder, J. C. [Oak Ridge Associated Universities (ORAU); Howard, Meredith E [ORNL; Liang, J Felix [ORNL; Manning, Brett M [ORNL; Varner Jr, Robert L [ORNL; Yu, Chang-Hong [ORNL

2014-01-01

342

Bias and linearity measurement of three axis fluxgate magnetometers using high precise electromagnetic devices  

Microsoft Academic Search

Bias error and linearity error influence the measurement precision of three axis fluxgate magnetometers. So, it is important to obtain and calibrate these errors. Bias error and linearity error of a German made DM-060 digital magnetometer are measured by precise electromagnetic devices. Firstly, bias of each axis is obtained by an alternating weak electromagnetic standard equipment. A method by comparing

Hong Feng Pang; Shi Tu Luo; Meng Chun Pan; Di Xiang Chen; Fei Lu Luo; Qi Zhang

2011-01-01

343

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

344

The Spring 1985 high precision baseline test of the JPL GPS-based geodetic system  

NASA Technical Reports Server (NTRS)

The Spring 1985 High Precision Baseline Test (HPBT) was conducted. The HPBT was designed to meet a number of objectives. Foremost among these was the demonstration of a level of accuracy of 1 to 2:10 to the 7th power, or better, for baselines ranging in length up to several hundred kilometers. These objectives were all met with a high degree of success, with respect to the demonstration of system accuracy in particular. The results from six baselines ranging in length from 70 to 729 km were examined for repeatability and, in the case of three baselines, were compared to results from colocated VLBI systems. Repeatability was found to be 5:10 to the 8th power (RMS) for the north baseline coordinate, independent of baseline length, while for the east coordinate RMS repeatability was found to be larger than this by factors of 2 to 4. The GPS-based results were found to be in agreement with those from colocated VLBI measurements, when corrected for the physical separations of the VLBI and CPG antennas, at the level of 1 to 2:10 to the 7th power in all coordinates, independent of baseline length. The results for baseline repeatability are consistent with the current GPA error budget, but the GPS-VLBI intercomparisons disagree at a somewhat larger level than expected. It is hypothesized that these differences may result from errors in the local survey measurements used to correct for the separations of the GPS and VLBI antenna reference centers.

Davidson, John M.; Thornton, Catherine L.; Stephens, Scott A.; Blewitt, Geoffrey; Lichten, Stephen M.; Sovers, Ojars J.; Kroger, Peter M.; Skrumeda, Lisa L.; Border, James S.; Neilan, Ruth E.

1987-01-01

345

High-Precision (143)Nd/(144)Nd Ratios from NdO(+) Data Corrected with in-Run Measured Oxygen Isotope Ratios.  

PubMed

The NdO(+) technique has been considerably refined in recent years for high-precision measurement of Nd isotope ratios in low-level samples (1-5 ng Nd). As oxygen isotopic compositions may vary significantly with experimental conditions such as filament material, ionization enhancer and the ambient oxygen in the ion source, great "care" should be taken for using correct oxygen isotopic compositions to do the isobaric oxide corrections for the "conventional" NdO(+) method. Our method presented here for NdO(+) data reduction and PrO(+) interference corrections uses the oxygen isotope composition determined in each cycle of the NdO(+) measurements. For that purpose, we measured the small ion signals of (150)Nd(17)O(+) and (150)Nd(18)O(+) with amplifiers equipped with 10(12) ? feedback resistors, and those of Nd(16)O(+) ion beams with 10(11) ? amplifiers. Using 10(12) ? amplifiers facilitates a precise measurement of the very small (150)Nd(17)O(+) and (150)Nd(18)O(+) ion signals and calculation of highly accurate and precise (143)Nd/(144)Nd isotope ratios. The (143)Nd/(144)Nd ratios for JNdi-1 standards and several whole-rock reference materials determined with the method on 4 ng of Nd loads are consistent with previously reported values within analytical error, with internal and external precision (2 RSE and 2 RSD) of better than 20 and 30 ppm, respectively. PMID:25301302

Chu, Zhu-Yin; Li, Chao-Feng; Hegner, Ernst; Chen, Zhi; Yan, Yan; Guo, Jing-Hui

2014-11-18

346

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

347

Improved strain precision with high spatial resolution using nanobeam precession electron diffraction  

SciTech Connect

NanoBeam Electron Diffraction is a simple and efficient technique to measure strain in nanostructures. Here, we show that improved results can be obtained by precessing the electron beam while maintaining a few nanometer probe size, i.e., by doing Nanobeam Precession Electron Diffraction (N-PED). The precession of the beam makes the diffraction spots more uniform and numerous, making N-PED more robust and precise. In N-PED, smaller probe size and better precision are achieved by having diffraction disks instead of diffraction dots. Precision in the strain measurement better than 2?×?10{sup ?4} is obtained with a probe size approaching 1?nm in diameter.

Rouviere, Jean-Luc, E-mail: jean-luc.rouviere@cea.fr; Martin, Yannick [CEA-INAC/UJF-Grenoble UMR-E, SP2M, LEMMA, Minatec Grenoble F-38054 (France)] [CEA-INAC/UJF-Grenoble UMR-E, SP2M, LEMMA, Minatec Grenoble F-38054 (France); Béché, Armand [CEA-INAC/UJF-Grenoble UMR-E, SP2M, LEMMA, Minatec Grenoble F-38054 (France) [CEA-INAC/UJF-Grenoble UMR-E, SP2M, LEMMA, Minatec Grenoble F-38054 (France); FEI Electron Optics, Achtseweg Noord 5, 5651 GG Eindhoven (Netherlands); Electron Microscopy for Materials Science (EMAT), University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Denneulin, Thibaud; Cooper, David [CEA, LETI, Minatec, F-38054 Grenoble (France)] [CEA, LETI, Minatec, F-38054 Grenoble (France)

2013-12-09

348

High-precision prompt-?-ray spectral data from the reaction Pu241(nth, f)  

NASA Astrophysics Data System (ADS)

In this paper we present results from the first high-precision prompt-?-ray spectral measurements from the reaction Pu241(nth, f). Apart from one recent experiment, no data are reported in the literature for this fissioning system, which motivated a new dedicated experiment. We have measured prompt-fission ? rays with three cerium-doped LaBr3 (two 5.08cm×5.08 cm and one 7.62cm×7.62 cm) and one CeBr3 (5.08cm×5.08 cm) scintillation detectors, which all exhibit excellent timing and good energy resolution. The average ?-ray multiplicity was determined to be ?¯?=(8.21±0.09) per fission, the average energy to be ??=(0.78±0.01) MeV, and the total energy to be E? ,tot=(6.41±0.06) MeV as the weighted average from all detectors. Since the results from all detectors are in excellent agreement, and the total released ? energy is modestly higher than the one in the present evaluated nuclear data files, we suspect that the underestimation of the prompt-? heating in nuclear reactors is due to fast-neutron-induced fission on U238 or rather from fission induced by ? rays from neutron capture in the construction material.

Oberstedt, S.; Billnert, R.; Belgya, T.; Bry?, T.; Geerts, W.; Guerrero, C.; Hambsch, F.-J.; Kis, Z.; Moens, A.; Oberstedt, A.; Sibbens, G.; Szentmiklosi, L.; Vanleeuw, D.; Vidali, M.

2014-08-01

349

High-precision estimate of the critical exponents for the directed Ising universality class  

NASA Astrophysics Data System (ADS)

With extensive Monte Carlo simulations, we present high-precision estimates of the critical exponents of branching annihilating random walks with two offspring, a prototypical model of the directed Ising universality class in one dimension. To estimate the exponents accurately, we propose a systematic method to find corrections to scaling whose leading behavior is supposed to take the form t -? in the long-time limit at the critical point. Our study shows that ? ? 0.75 for the number of particles in defect simulations and ? ? 0.5 for other measured quantities, which should be compared with the widely used value of ? = 1. Using ? so obtained, we analyze the effective exponents to find that ?/? ? = 0.2872(2), z = 1.7415(5), ? = 0.0000(2), and accordingly, ?/? ? = 0.5000(6). Our numerical results for ?/? ? and z are clearly different from the conjectured rational numbers ?/? ? = tfrac{2} {7} ? 0.2857, z = tfrac{7} {4} = 1.75 by Jensen [Phys. Rev. E, 50, 3623 (1994)]. Our result for ?/? ?, however, is consistent with tfrac{1} {2} , which is believed to be exact.

Park, Su-Chan

2013-02-01

350

Validation of Map Matching Algorithms using High Precision Positioning with GPS  

NASA Astrophysics Data System (ADS)

Map Matching (MM) algorithms are usually employed for a range of transport telematics applications to correctly identify the physical location of a vehicle travelling on a road network. Two essential components for MM algorithms are (1) navigation sensors such as the Global Positioning System (GPS) and dead reckoning (DR), among others, to estimate the position of the vehicle, and (2) a digital base map for spatial referencing of the vehicle location. Previous research by the authors (Quddus et al., 2003; Ochieng et al., 2003) has developed improved MM algorithms that take account of the vehicle speed and the error sources associated with the navigation sensors and the digital map data previously ignored in conventional MM approaches. However, no validation study assessing the performance of MM algorithms has been presented in the literature. This paper describes a generic validation strategy and results for the MM algorithm previously developed in Ochieng et al. (2003). The validation technique is based on a higher accuracy reference (truth) of the vehicle trajectory as determined by high precision positioning achieved by the carrier-phase observable from GPS. The results show that the vehicle positions determined from the MM results are within 6 m of the true positions. The results also demonstrate the importance of the quality of the digital map data to the map matching process.

Quddus, Mohammed A.; Noland, Robert B.; Ochieng, Washington Y.

2005-05-01

351

Research on the polishing technology of high-precision aspherical cylindrical lens  

NASA Astrophysics Data System (ADS)

Aspherical cylindrical lens compared with the cylindrical lens, they improved image quality and optical properties, simplified the system architecture. They applied in many fields, such as high power laser system, fax machines and typographical scan imaging system, as well as bar code scanning, lighting and other aspects of holography. Aspherical cylindrical lens are centrosymmetric. It is difficult to process. Parallel with the side line and bus bar line is difficult to ensure. Machining accuracy is low. It is usually about 15 ?m, that not sufficient to meet the needs of modern highprecision laser systems. These have become a major problem restricting its development. Combining traditional and modern polishing techniques, a new technique for polishing aspherical cylindrical lens is proposed-- longitudinal feedback compensation technology. With dimensions of 15 × 5 × 5 mm quartz aspherical cylindrical lens as an example, the surface profilometer results of detection of the workpiece usually, modify the shape of the polishing surface of the mold, to control the size of the area of the polishing, the surface of the workpiece to achieve the effect of the type of compensation. After repeated testing and feedback compensation, gradually improve the accuracy of the workpiece surface type. The results show that this technique can effectively improve the precision aspherical cylindrical lens. After detection the workpiece surface accuracy is 0.8?m, the surface finish is Class II. It has the actual production of a certain application value.

Fu, Xiu-hua; Wang, Zhe; Jia, Zong-he; Dong, Huan; Liu, Dan; Zhang, Chuan-xin

2014-08-01

352

Recent developments for high-precision mass measurements of the heaviest elements at SHIPTRAP  

NASA Astrophysics Data System (ADS)

Atomic nuclei far from stability continue to challenge our understanding. For example, theoretical models have predicted an “island of stability” in the region of the superheavy elements due to the closure of spherical proton and neutron shells. Depending on the model, these are expected at Z = 114, 120 or even 126 and N = 172 or 184. Valuable information on the road to the island of stability is derived from high-precision mass measurements, which give direct access to binding energies of short-lived trans-uranium nuclei. Recently, direct mass measurements at SHIPTRAP have been extended to nobelium and lawrencium isotopes around the deformed shell gap N = 152. In order to further extend mass measurements to the region of superheavy elements, new technical developments are required to increase the performance of our setup. The sensitivity will increase through the implementation of a new detection method, where observation of one single ion is sufficient. Together with the use of a more efficient gas stopping cell, this will us allow to significantly enhance the overall efficiency of SHIPTRAP.

Minaya Ramirez, E.; Ackermann, D.; Blaum, K.; Block, M.; Droese, C.; Düllmann, Ch. E.; Eibach, M.; Eliseev, S.; Haettner, E.; Herfurth, F.; Heßberger, F. P.; Hofmann, S.; Marx, G.; Nesterenko, D.; Novikov, Yu. N.; Plaß, W. R.; Rodríguez, D.; Scheidenberger, C.; Schweikhard, L.; Thirolf, P. G.; Weber, C.

2013-12-01

353

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

354

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

355

PRECISE HIGH-CADENCE TIME SERIES OBSERVATIONS OF FIVE VARIABLE YOUNG STARS IN AURIGA WITH MOST  

SciTech Connect

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.

Cody, Ann Marie; Tayar, Jamie; Hillenbrand, Lynne A. [Department of Astrophysics, California Institute of Technology, MC 249-17, Pasadena, CA 91125 (United States); Matthews, Jaymie M. [Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia V6T 1Z1 (Canada); Kallinger, Thomas, E-mail: amc@ipac.caltech.edu [Institut fuer Astronomie, Universitaet Wien, Tuerkenschanzstrasse 17, A-1180 Vienna (Austria)

2013-03-15

356

High-precision thermodynamic and critical properties from tensor renormalization-group flows.  

PubMed

The recently developed tensor renormalization-group (TRG) method provides a highly precise technique for deriving thermodynamic and critical properties of lattice Hamiltonians. The TRG is a local coarse-graining transformation, with the elements of the tensor at each lattice site playing the part of the interactions that undergo the renormalization-group flows. These tensor flows are directly related to the phase diagram structure of the infinite system, with each phase flowing to a distinct surface of fixed points. Fixed-point analysis and summation along the flows give the critical exponents, as well as thermodynamic functions along the entire temperature range. Thus, for the ferromagnetic triangular lattice Ising model, the free energy is calculated to better than 10(-5) along the entire temperature range. Unlike previous position-space renormalization-group methods, the truncation (of the tensor index range D) in this general method converges under straightforward and systematic improvements. Our best results are easily obtained with D=24, corresponding to 4624-dimensional renormalization-group flows. PMID:18351815

Hinczewski, Michael; Berker, A Nihat

2008-01-01

357

Highly precise nonlinear error calibrating system based on Fabry-Perot interferometer  

NASA Astrophysics Data System (ADS)

Nanometer measurement has become more and more important in the development of metrology, material science, microelectronics and biology. Heterodyne Fabry-Perot interferometer can be used in the nonlinear error calibration with an accuracy of nanometer and sub-nanometer order. We can get very high resolution by using heterodyne Fabry-Perot interferometer frequency locking technique in theory. However, the measure uncertainty and the stability of results are worse than the expectation's. In this paper, in order to solve the problems of air refrective index change and temperature excursion, we designed the vacuum system that adjusts the interference light path and built it based on NIM's heterodyne Fabry-Perot interferometer. The key in our design is to reduce the thermic balance time and to ensure reliable hermetization of movable components. The influnce of the change of air refractive index to the measured precision was studied, and the approximate formula of vacuum degree that the system requires was concluded. It has been proved in the experiment that the system works steadily. The system's ability of anti-jamming has been improved, and the demand of the measure surroundings has been lowered. Comparing with capacitance displacement measurement instrument, we conclude that the nonlinear degree of this system in the range of 0.35um, which is longer than half of the wavelength of the laser, is better than 3.9nm.

Ma, Jichi; Li, Yan; Yin, Chunyong

2008-03-01

358

Design principle of high-precision flexure mechanisms based on parasitic-motion compensation  

NASA Astrophysics Data System (ADS)

In design of flexure mechanism, diminishing the parasitic-motion is a key point to improve the accuracy. However, most of existing topics concentrate on improving the accuracy of linear-motion flexure mechanisms via compensating the parasitic error, but few research the multi-dimensional flexure mechanisms. A general design principle and method for high-precision flexure mechanisms based on the parasitic-motion compensation is presented, and the proposed method can compensate the parasitic rotation in company with translation, or the parasitic translation in company with rotation, or both. The crucial step for the method is that the parasitic motion of a flexure mechanism is formulated and evaluated in terms of its compliance. The overall compliance matrix of a general flexure mechanism is formulated by using screw theory firstly, then the criteria for the parasitic motions is introduced by analyzing the characteristics of the resultant compliance matrix as well as with aid of the concept of instantaneous rotation center. Subsequently, a compliance-based compensation approach for reducing parasitic-motion is addressed as the most important part. The design principles and procedure are further discussed to help with improving the accuracy of flexure mechanisms, and case studies are provided to illustrate this method. Finally, an analytical verification is provided to demonstrate that the symmetry design philosophy widely used in flexure design can effectively improve accuracy in terms of the proposed method. The proposed compensation method can be well used to diminish the parasitic-motion of multi-dimensional flexure mechanisms.

Li, Shouzhong; Yu, Jingjun

2014-07-01

359

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

360

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

361

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.

2012-03-01

362

The significance of GPS/leveling points for the high precision geoid computation  

NASA Astrophysics Data System (ADS)

The computation of a local geoid can be done by several methods. Collocation as one of the possible tools has the big advantage that observations representing different functionals of the disturbing potential can be combined. Therefore also GPS/leveling points can be used as observation values. The present work discusses the significance of GPS/leveling data in the collocation process as well as the overall importance of this kind of data in the field of the high precision geoid computation. Several basic principles are discussed. Is the combination of GPS/leveling data with the other gravity field observations in one step better than performing the widely used two step procedure? The two step procedure means combining gravity anomalies and deflections of the vertical in a first step, followed by the fitting of the geoidal surface to the GPS/leveling benchmarks by a transformation surface. The present work also focuses on the modeling of the transformation surface by radial base functions. An adapted version of the Greedy algorithm is used to find the minimum number of GPS/leveling points that are necessary to fix the transformation surface with a given accuracy. Finally the principle of a possible validation of the GPS/leveling points by a combined leave one out cross validation is discussed.

Kühtreiber, N.; Pock, C.

2012-04-01

363

Quantitative Design of Regulatory Elements Based on High-Precision Strength Prediction Using Artificial Neural Network  

PubMed Central

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

Xiong, Zhiqiang; Xu, Feng; Zhao, Guoping; Wang, Yong

2013-01-01

364

High-precision diode-laser-based temperature measurement for air refractive index compensation.  

PubMed

We present a laser-based system to measure the refractive index of air over a long path length. In optical distance measurements, it is essential to know the refractive index of air with high accuracy. Commonly, the refractive index of air is calculated from the properties of the ambient air using either Ciddor or Edlén equations, where the dominant uncertainty component is in most cases the air temperature. The method developed in this work utilizes direct absorption spectroscopy of oxygen to measure the average temperature of air and of water vapor to measure relative humidity. The method allows measurement of temperature and humidity over the same beam path as in optical distance measurement, providing spatially well-matching data. Indoor and outdoor measurements demonstrate the effectiveness of the method. In particular, we demonstrate an effective compensation of the refractive index of air in an interferometric length measurement at a time-variant and spatially nonhomogeneous temperature over a long time period. Further, we were able to demonstrate 7 mK RMS noise over a 67 m path length using a 120 s sample time. To our knowledge, this is the best temperature precision reported for a spectroscopic temperature measurement. PMID:22086025

Hieta, Tuomas; Merimaa, Mikko; Vainio, Markku; Seppä, Jeremias; Lassila, Antti

2011-11-01

365

High-precision diode-laser-based temperature measurement for air refractive index compensation  

SciTech Connect

We present a laser-based system to measure the refractive index of air over a long path length. In optical distance measurements, it is essential to know the refractive index of air with high accuracy. Commonly, the refractive index of air is calculated from the properties of the ambient air using either Ciddor or Edlen equations, where the dominant uncertainty component is in most cases the air temperature. The method developed in this work utilizes direct absorption spectroscopy of oxygen to measure the average temperature of air and of water vapor to measure relative humidity. The method allows measurement of temperature and humidity over the same beam path as in optical distance measurement, providing spatially well-matching data. Indoor and outdoor measurements demonstrate the effectiveness of the method. In particular, we demonstrate an effective compensation of the refractive index of air in an interferometric length measurement at a time-variant and spatially nonhomogeneous temperature over a long time period. Further, we were able to demonstrate 7 mK RMS noise over a 67 m path length using a 120 s sample time. To our knowledge, this is the best temperature precision reported for a spectroscopic temperature measurement.

Hieta, Tuomas; Merimaa, Mikko; Vainio, Markku; Seppae, Jeremias; Lassila, Antti

2011-11-01

366

A new method of gravity external correction for high precision gravity measurement  

NASA Astrophysics Data System (ADS)

There are a large number of simplifying assumptions in the external gravity correction methods in order to reduce the amount of calculation and improve the efficiency of operation. However, there are some problems caused by the simplifying assumptions, for example, errors in normal gravity caused by the confusion of ellipsoids, the indirect effect caused by the difference between the geoid surface and the ellipsoid surface, errors in the Bouguer correction caused by the improper selection of the density and destruction of structure caused by the Bouguer correction. In order to overcome this problem, we proposed a new method of gravity external correction for high precision gravity measurement. There are two steps in the correction method. The first one is to calculate the normal gravity of stations in any position with arbitrary latitude and geodetic height and then gravity anomaly is calculated by subtracting normal gravity from absolute gravity. The gravity anomaly to the position of station can be calculated instead of the gravity anomaly relative to the datum. Using some theoretical models and actual data in western China, we verified the gravity correction method proposed in the paper, and the result showed that the method can improve the accuracy and exploration effect of gravity exploration.

Luo, Di; Cai, Feng; Liu, Zhan

2014-10-01

367

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

368

Procyon: Constraining Its Temperature Structure with High-Precision Interferometry and 3-D Model Atmospheres  

NASA Astrophysics Data System (ADS)

We have fit synthetic visibilities from 3-D (CO5BOLD + PHOENIX) and 1-D (PHOENIX, ATLAS12) model stellar atmospheres for Procyon (F5 IV) to high-precision interferometric data from the VINCI instrument at the VLT Interferometer (K-band) and from the Mark III interferometer (500 nm, 800 nm). These data provide a test of theoretical wavelength-dependent limb-darkening predictions, and therefore Procyon's atmospheric temperature structure. Earlier work (Allende Prieto et al. 2002 ApJ 567, 544) has shown that the temperature structure from a spatially and temporally averaged 3-D hydrodynamical model produces significantly less limb darkening at 500 nm relative to the temperature structure from a 1-D MARCS model atmosphere which uses a mixing-length approximation for convective flux transport. Our direct fits to the interferometric data confirm this prediction, however we find that not all 1-D models fail to reproduce the observations. The key to matching the interferometric data is a shallower temperature gradient than provided by the standard 1-D mixing-length approximation. We find that in addition to our best fitting 3-D hydrodynamical model, a 1-D ATLAS12 model, with an additional free parameter for ``approximate overshooting'', provides the required temperature gradient. We estimate that an interferometric precision better than 0.1% will be required to distinguish between the 3-D model and the ATLAS12 model. This overshooting approximation has been shown to match Solar limb-darkening observations reasonably well (Castelli et al 1997 A&A 324, 432), however published work since using Strömgren photometry of solar-type stars has cast doubt on the importance of overshooting. We have also compared synthetic spectral energy distributions for Procyon to ultraviolet, optical and near-infrared spectrophotometry and find differences from comparisons to Strömgren photometry alone. This work was performed in part contract with the Jet Propulsion Laboratory (JPL) funded by NASA through the Michelson Fellowship Program. JPL is managed for NASA by the California Institute of Technology.

Aufdenberg, J. P.; Ludwig, H.-G.; Kervella, P.

2004-12-01

369

Highly selective and precisely controlled aluminum etching by Ar/HBr/CH3F/O2 gas chemistry  

NASA Astrophysics Data System (ADS)

Highly selective and precisely controlled aluminum etching was investigated by using plasma with a new Ar/HBr/CH3F/O2 gas chemistry. Generally, an aluminum surface is oxidized, leading to difficulties in the precise control of nm/min-level aluminum etching with a high selectivity to SiO2 of more than 10. The new gas chemistry enabled precise aluminum etching with a high selectivity to oxide of 10 and a low etching rate of 10 nm/min. In this gas chemistry, the aluminum surface remained oxidized by oxygen during etching and the oxidized surface was reduced by CH3F. The oxidized aluminum surface was etched by radicals from CH3F and the etching rate was decreased by HBr.

Suzuki, Eiji; Ohtake, Hiroto; Ohsawa, Yusuke; Kumar, Kaushik; Sasaki, Masaru

2014-01-01

370

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

371

High-precision Non-Contact Measurement of Creep of Ultra-High Temperature Materials for Aerospace  

NASA Technical Reports Server (NTRS)

For high-temperature applications (greater than 2,000 C) such as solid rocket motors, hypersonic aircraft, nuclear electric/thermal propulsion for spacecraft, and more efficient jet engines, creep becomes one of the most important design factors to be considered. Conventional creep-testing methods, where the specimen and test apparatus are in contact with each other, are limited to temperatures approximately 1,700 C. Development of alloys for higher-temperature applications is limited by the availability of testing methods at temperatures above 2000 C. Development of alloys for applications requiring a long service life at temperatures as low as 1500 C, such as the next generation of jet turbine superalloys, is limited by the difficulty of accelerated testing at temperatures above 1700 C. For these reasons, a new, non-contact creep-measurement technique is needed for higher temperature applications. A new non-contact method for creep measurements of ultra-high-temperature metals and ceramics has been developed and validated. Using the electrostatic levitation (ESL) facility at NASA Marshall Space Flight Center, a spherical sample is rotated quickly enough to cause creep deformation due to centrifugal acceleration. Very accurate measurement of the deformed shape through digital image analysis allows the stress exponent n to be determined very precisely from a single test, rather than from numerous conventional tests. Validation tests on single-crystal niobium spheres showed excellent agreement with conventional tests at 1985 C; however the non-contact method provides much greater precision while using only about 40 milligrams of material. This method is being applied to materials including metals and ceramics for non-eroding throats in solid rockets and next-generation superalloys for turbine engines. Recent advances in the method and the current state of these new measurements will be presented.

Rogers, Jan R.; Hyers, Robert

2008-01-01

372

Optimizing Spatial Frequency Data Weights for High Precision Imaging with ALMA  

NASA Astrophysics Data System (ADS)

We have conducted imaging simulations of observations for wide field with ALMA (Atacama Large Millimeter/submillimeter Array), which consists of ACA measuring very short spacing visibilities and 12 m Array measuring longer spacing visibilities. The results show that big uv response gap between shorter spacings and longer spacings degrades image precision considerably. It suggests importance of sensitivity equalization in uv domain between ACA and 12 m Array for obtaining precise images.

Morita, K.-I.; Kurono, Y.; Kamazaki, T.

2010-12-01

373

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

374

A 1000-year high precision record of ?13C in atmospheric CO2  

NASA Astrophysics Data System (ADS)

We present measurements of the stable carbon isotope ratio in air extracted from Antarctic ice core and firn samples. The same samples were previously used by Etheridge and co-workers to construct a high precision 1000-year record of atmospheric CO2 concentration, featuring a close link between the ice and modern records and high-time resolution. Here, we start by confirming the trend in the Cape Grim in situ ?13C record from 1982 to 1996, and extend it back to 1978 using the Cape Grim Air Archive. The firn air ?13C agrees with the Cape Grim record, but only after correction for gravitational separation at depth, for diffusion effects associated with disequilibrium between the atmosphere and firm, and allowance for a latidudinal gradient in ?13C between Cape Grim and the Antarctic coast. Complex calibration strategies are required to cope with several additional systematic influences on the ice core ?13C record. Errors are assigned to each ice core value to reflect statistical and systematic biases (between ± 0.025‰ and ± 0.07‰); uncertainties (of up to ± 0.05‰) between core-versus-core, ice-versus-firn and firn-versus-troposphere are described separately. An almost continuous atmospheric history of ?13C over 1000years results, exhibiting significant decadal-to-century scale variability unlike that from earlier proxy records. The decrease in ?13C from 1860 to 1960 involves a series of steps confirming enhanced sensitivity of ?13C to decadal timescale-forcing, compared to the CO2 record. Synchronous with a ''Little Ice Age'' CO2 decrease, an enhancement of ?13C implies a terrestrial response to cooler temperatures. Between 1200 AD and 1600 AD, the atmospheric ?13C appear stable.

Francey, R. J.; Allison, C. E.; Etheridge, D. M.; Trudinger, C. M.; Enting, I. G.; Leuenberger, M.; Langenfelds, R. L.; Michel, E.; Steele, L. P.

1999-04-01

375

A high-resolution multi-reflection time-of-flight mass spectrograph for precision mass measurements at RIKEN/SLOWRI  

NASA Astrophysics Data System (ADS)

A multi-reflection time-of-flight mass spectrograph (MRTOF-MS) has been implemented at RIKEN to provide high-precision mass measurements of very short-lived nuclei with half-lives down to ?10 ms. Such measurements are of particular interest for r-process nuclei and trans-Uranium nuclei. We provide a detailed description of the mechanical construction and electronics implementation of an MRTOF-MS at RIKEN. The resolving power is investigated by numerical simulation and these simulations are compared to experimental observations to understand the effects of voltage and thermal instabilities. The limits of precision and accuracy are investigated using offline ion sources, and the effects of non-isobaric contaminants are reported.

Schury, P.; Wada, M.; Ito, Y.; Arai, F.; Naimi, S.; Sonoda, T.; Wollnik, H.; Shchepunov, V. A.; Smorra, C.; Yuan, C.

2014-09-01

376

Precise vs. UltraLight Activity Diagrams - An Experimental Assessment in the Context of Business Process Modelling  

Microsoft Academic Search

\\u000a UML activity diagrams are a commonly used notation for modelling business processes in the field of both workflow automation\\u000a and requirements engineering. In this paper, we present a novel precise style for this notation. Further, the effectiveness\\u000a of this style has been investigated in the context of the modelling of business processes through a controlled experiment\\u000a conducted with master students

Francesco Di Cerbo; Gabriella Dodero; Gianna Reggio; Filippo Ricca; Giuseppe Scanniello

377

Progress on precision measurements of inner shell transitions in highly charged ions at an ECR ion source  

SciTech Connect

Inner shell transitions of highly charged ions produced in the plasma of an Electron Cyclotron Resonance Ion Source (ECRIS) were observed the first time by a Double Crystal Spectrometer (DCS). The DCS is a well-used tool in precision x-ray spectroscopy due to its ability of precision wavelength measurement traced back to a relative angle measurement. Because of its requirement for a bright x-ray source the DCS has not been used before in direct measurements of highly charged ions (HCI). Our new precision measurement of inner shell transitions in HCI is not just going to provide new x-ray standards for quantum metrology but can also give information about the plasma in which the ions reside. Ionic temperatures and with that the electron density can be determined by thorough examination of line widths measured with great accuracy.

Szabo, Csilla I.; Indelicato, Paul; LeBigot, Eric-Olivier; Vallette, Alexandre; Amaro, Pedro; Guerra, Mauro; Gumberidze, Alex [Laboratoire Kastler Brossel, Ecole Normale Superieure, CNRS, Universite Pierre et Marie Curie- Paris 6, Case 74, 4 place Jussieu, F-75005 Paris (France); Centro de Fisica Atomica, CFA, Departamento de Fisica (Portugal); Faculdade de Ciencias e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Laboratoire Kastler Brossel, Ecole Normale Superieure, CNRS, Universite Pierre et Marie Curie- Paris 6, Case 74, 4 place Jussieu, F-75005 Paris (France)

2012-05-25

378

High-precision gravimetric coulometry using the silver-perchloric acid coulometer: Titration of arsenious oxide with electrogenerated iodine.  

PubMed

High-precision gravimetric coulometry with a silver-perchloric acid coulometer is evaluated as an alternative to the conventional titrimetric method. The loss of weight (caused by electrolytic dissolution) of a highly pure silver anode in series with the cathode of a conventional constant-current titration system is measured and related to the number of equivalents of substance titrated. The precision of the method is determined by titrations of the Standard Reference Material 83C arsenious oxide (99.99% pure) with electrogenerated iodine, using biamperometric end-point detection. Depending on the size of the sample, an ultimate precision of 25 ppm is obtained. The assay for 0.5-g samples of the SRM material is 99.993(9) +/- 0.002(5)% purity. PMID:18962104

Newton, C M

1977-06-01

379

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 PMID:23433259

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

380

Glue test results for high-precision large cryogenic lens holder  

NASA Astrophysics Data System (ADS)

The Near Infrared Spectrometer and Photometer (NISP) of EUCLID requires high precision large lens holders (Ø170 mm) at cryogenic temperatures (150 K). The lenses of the optical system are glued into separate lens holders, the so called adaption rings. For the selection and verification of a suitable adhesive extensive glue selection tests are performed and results presented in this paper. With potential glue candidates, handling, single lap shear, connection tension and shear tests are carried out at room temperature (RT) and 150 K (OPS). For the NISP optical system DP490 is selected as the most suitable adhesive. The test results have shown that an even distribution of the glue in the glue gap is of crucial importance for the functioning and performance of the bonded lens system. The different coefficients of thermal expansion (CTE) between lens and lens holder produce large local mechanical stress and might cause lens breakage or failure of bonding. The design of the injection channel and the gluing procedure are developed to meet the lens performance requirements. An example is shown that after thermal cycling the remaining 0.5 mm - 1 mm thick adhesive in the injection channel results in large local mechanical stresses, and hence, damage of the lens. For a successful performance of the glue interface not only an optimum glue gap of 80 - 150 ?m is important, also micro-cracks of the glass at the gluing area have to be avoided. The performed glue tests with DP490 for 3 different lens/ring material combinations show sufficient mechanical tension and shear strength for bonding of the lens system. Titanium/LF5G15 and Invar/Fused Silica combinations have reached the strength of 30 MPa at RT and 50 GPa at 150 K. These results are presented on behalf of the EUCLID consortium.

Reutlinger, A.; Mottaghibonab, A.; Gal, C.; Boesz, A.; Grupp, F.; Geis, N.; Bode, A.; Katterloher, R.; Bender, R.

2012-09-01

381

Use of high precision Satellite Laser Ranging Data in Space Geodynamics  

NASA Astrophysics Data System (ADS)

Satellite laser ranging (SLR) data analysis is one of the modern techniques used to derive the Earth rotation parameters (ERP) and to establish a Terrestrial Reference Frame (TRF) realization. Information on the ERP and TRF is widely used in astrometry, geodynamics and geodesy, in particular, in the Terrestrial and Celestial Reference Frames transformation. Algorithms developed to model the geodynamic satellite Lageos-1 and Lageos-2 motion are described in the paper. The model precision is at a few centimeter level at two-week intervals. The paper presents the recent results of the joint processing of Lageos-1 and Lageos-2 SLR data acquired by the global network of 103 stations in 1983--1996. The data were mainly obtained from the Crustal Dynamics Data Information System (CDDIS), NASA. The data analysis has been performed using KIEV-GEODYNAMICS 5.2 software which basically follows the IERS Conventions [2] with some exceptions. The aim of the analysis was to derive the Earth rotation parameters at 13.3-year time interval and SLR tracking stations coordinates and velocities. We have obtained a set of the Earth rotation parameters (xp, yp pole coordinates, UT1-UTC) on three-day intervals since MJD 45583 till MJD 50445, coordinates of 101 SLR stations at epoch January 1, 1993 (MJD 48898) and velocities of 50 sites (66 collocated stations) with good observing histories and sufficient amount of high quality data. The formal rms errors of the station coordinates are at the level of 0.1--1 cm for the majority of the stations. The derived station coordinates and velocities have been compared with ITRF94 [1]. The Terrestrial Reference Frame realization given by our solution is at the centimeter level in agreement with the ITRF94. Our solution for ERP has been compared with the {EOP(IERS) C 04} series. The formal errors are 0.4 milliarc second for pole coordinates and 0.03 millisecond for the Universal Time.

Rudenko, S.

382

Water and solute balances of erosion-affected Haplic Luvisols using high precision weighing lysimeter data  

NASA Astrophysics Data System (ADS)

Under intensive agricultural use, soil landscape development leads to more-or-less eroded areas reflecting an erosion-induced spatial differentiation of soil types. This is a general problem in regions with soil erosion such as hilly loess soil regions or hummocky ground moraine soil landscapes. The water flow and solute transport is affected by soil-crop interactions depending on properties of differently-developed soil horizons. The objective was to analyze and compare the measured water and solute balance for differently-eroded Haplic Luvisols. All results were based on high precision weighing lysimeters filled with intact soil monoliths. Differences in seepage water drainage of about >76 % between most and least eroded soils indicated erosion-induced spatial differentiation in the water balance of the same soil type. Cumulative drainage was ranging between 190 L m-2 (Standard Haplic Luvisol) and 290 L m-2 (Most eroded Haplic Luvisol) over 2.5 years (04/2011-10/2013). Due to more or less similar concentrations of dissolved organic carbon (DOC) of 4.8 ± 0.5 mg L-1, and of dissolved inorganic carbon (DIC) of 61.5 ± 5.3 mg L-1, for the lysimeter bottom at140 cm soil depth, results suggest leaching was predominantly affected by water fluxes. The export of dissolved carbon ranged from 1.5 ± 0.3 g m-2 for DOC and 16.1 ± 2.5 g m-2 for DIC over the period of 2.5 years. Effects of erosion-affected pedogenesis could be related to leaching rates. Element leaching, in particularly phosphate, indicated occasionally occurrence of preferential flow. Results suggest that water and solute balances are depending on the degree of erosion-induced soil profile modifications. Hence for the landscape scale analysis, not only the distributed soil types but also erosion-induced modifications with a single soil type should be considered for quantification of the landscape water and solute balances.

Herbrich, Marcus; Gerke, PD Horst H., ,, Dr.; Sommer, Michael, ., Dr. _., Prof.

2014-05-01

383

Methods for the Analysis of High Precision Differential Hydrogen Deuterium Exchange Data.  

PubMed

Hydrogen/deuterium exchange (HDX) mass spectrometry has been widely applied to the characterization of protein dynamics. More recently, differential HDX has been shown to be effective for the characterization of ligand binding. Previously we have described a fully automated HDX system for use as a ligand screening platform. Here we describe and validate the required data analysis workflow to facilitate the use of HDX as a robust approach for ligand screening. Following acquisition of HDX data at a single on-exchange time point (n ? 3), one way analysis of variance in conjunction with the Tukey multiple comparison procedure is used to establish the significance of any measured difference. Analysis results are graphed with respect to a single peptide, ligand or group of ligands, or displayed as an overview within a heat map. For the heat map display, only ?%D values with a Tukey-adjusted P value less than 0.05 are colored. Hierarchical clustering is used to bin compounds with highly similar HDX signatures. The workflow is evaluated with a small data set showing the ligand binding domain (LDB) of the nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR?) screened against 10 functionally selective ligands. More significantly, data for the vitamin D receptor (VDR) in complex with 87 ligands are presented. To highlight the robustness and precision of our automated HDX platform we analyzed the data from 4191 replicate HDX measurements acquired over an eight month timeframe. Ninety six percent of these measurements were within 10 percent of the mean value. Work has begun to integrate these analysis and graphing components within our HDX software suite. PMID:21528013

Chalmers, Michael J; Pascal, Bruce D; Willis, Scooter; Zhang, Jun; Iturria, Stephen J; Dodge, Jeffery A; Griffin, Patrick R

2011-04-30

384

Employing Tropospheric Numerical Weather Prediction Model for High-Precision GNSS Positioning  

NASA Astrophysics Data System (ADS)

In the past few years is increasing the necessity of realizing high accuracy positioning. In this sense, the spatial technologies have being widely used. The GNSS (Global Navigation Satellite System) has revolutionized the geodetic positioning activities. Among the existent methods one can emphasize the Precise Point Positioning (PPP) and network-based positioning. But, to get high accuracy employing these methods, mainly in real time, is indispensable to realize the atmospheric modeling (ionosphere and troposphere) accordingly. Related to troposphere, there are the empirical models (for example Saastamoinen and Hopfield). But when highly accuracy results (error of few centimeters) are desired, maybe these models are not appropriated to the Brazilian reality. In order to minimize this limitation arises the NWP (Numerical Weather Prediction) models. In Brazil the CPTEC/INPE (Center for Weather Prediction and Climate Studies / Brazilian Institute for Spatial Researches) provides a regional NWP model, currently used to produce Zenithal Tropospheric Delay (ZTD) predictions (http://satelite.cptec.inpe.br/zenital/). The actual version, called eta15km model, has a spatial resolution of 15 km and temporal resolution of 3 hours. In this paper the main goal is to accomplish experiments and analysis concerning the use of troposphere NWP model (eta15km model) in PPP and network-based positioning. Concerning PPP it was used data from dozens of stations over the Brazilian territory, including Amazon forest. The results obtained with NWP model were compared with Hopfield one. NWP model presented the best results in all experiments. Related to network-based positioning it was used data from GNSS/SP Network in São Paulo State, Brazil. This network presents the best configuration in the country to realize this kind of positioning. Actually the network is composed by twenty stations (http://www.fct.unesp.br/#!/pesquisa/grupos-de-estudo-e-pesquisa/gege//gnss-sp-network2789/). The results obtained employing NWP model also were compared to Hopfield one, and the results were very interesting. The theoretical concepts, experiments, results and analysis will be presented in this paper.

Alves, Daniele; Gouveia, Tayna; Abreu, Pedro; Magário, Jackes

2014-05-01

385

Application of high precision band structure calculations to the equation of state for beryllium oxide: SESAME equation of state number 7612  

SciTech Connect

High precision electronic band structure calculations for BeO have revealed a large volume discontinuity structural phase transition on the 0 K isotherm at about 1 Mbar. Although, this transition has not been observed experimentally, the accuracy of the calculations is such that the existence of this transition is unambiguous. A transition of this magnitude is likely to have a substantial impact on hydrodynamic simulations involving BeO. Here we report the creation of a new SESAME equations of state for BeO which incorporates the effect of the theoretically determined phase transition. This new EOS will be added to the SESAME library as material number 7612.

Boettger, J.C.; Wills, J.M.

1992-03-01

386

Fabrication and Metrology of High-Precision Foil Mirror Mounting Elements  

NASA Technical Reports Server (NTRS)

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-ray Telescope (SXT) development effort at Goddard Space Flight Center (GSFC). MIT developed improved methods for fabricating and characterizing the precision silicon micro-combs. MIT also developed and characterized assembly tools and several types of metrology tools in order to characterize and reduce the errors associated with precision assembly of foil optics. Results of this effort were published and presented to the scientific community and the GSFC SXT team. A bibliography of papers and presentations is offered.

Schattenburg, Mark L.

2002-01-01

387

High-precision figure correction of x-ray telescope optics using ion implantation  

NASA Astrophysics Data System (ADS)

Achieving both high resolution and large collection area in the next generation of x-ray telescopes requires highly accurate shaping of thin mirrors, which is not achievable with current technology. Ion implantation offers a promising method of modifying the shape of mirrors by imparting internal stresses in a substrate, which are a function of the ion species and dose. This technique has the potential for highly deterministic substrate shape correction using a rapid, low cost process. Wafers of silicon and glass (D-263 and BK-7) have been implanted with Si+ ions at 150 keV, and the changes in shape have been measured using a Shack-Hartmann metrology system. We show that a uniform dose over the surface repeatably changes the spherical curvature of the substrates, and we show correction of spherical curvature in wafers. Modeling based on experiments with spherical curvature correction shows that ion implantation could be used to eliminate higher-order shape errors, such as astigmatism and coma, by using a spatially-varying implant dose. We will report on progress in modelling and experimental tests to eliminate higher-order shape errors. In addition, the results of experiments to determine the thermal and temporal stability of implanted substrates will be reported.

Chalifoux, Brandon; Sung, Edward; Heilmann, Ralf K.; Schattenburg, Mark L.

2013-09-01

388

Experimental studies of excitons at high densities  

Microsoft Academic Search

We have given a discussion of some of the types of experiments that can be conducted on HDE systems. We have discussed, in detail, reflectivity of intense light beams and optical gain measurements on highly excited CuCl. We find that the reflectivity spectra are modified when a high intensity probe is used, and that this modification can be phenomenologically explained

K. L. SHAKLEE

389

High-precision shape measurement by white-light interferometry with real-time scanner error correction  

Microsoft Academic Search

White-light interferometric techniques allow high-precision shape measurement of objects with discontinuous structures by detecting the peak of the coherence envelope. These techniques assume a specific change in the optical path difference (OPD) between the interfering beams; however, the scanning device effecting that change often introduces OPD errors that are carried over to the measurements. We present a technique for measuring

Joanna Schmit; Artur Olszak

2002-01-01

390

Analysing the Creep of Mountain Permafrost using High Precision Aerial Photogrammetry: 25 Years of Monitoring Gruben Rock Glacier, Swiss Alps  

E-print Network

Analysing the Creep of Mountain Permafrost using High Precision Aerial Photogrammetry: 25 Years the three-dimensional surface kinematics of creeping mountain permafrost. In places, the area under study in the `glacier-aected' part of the rock glacier which still contains some dead glacier ice in permafrost

Kääb, Andreas

391

Modeling and compensation of cutting-forces generated during the EDM process for ultra high-precision robots  

E-print Network

on the robot Agietron micro-nano as a case study and we have used an ultra high-precision measuring system the deformations in real-time. 1 Introduction Robot calibration is a process that permits to increase ro- bot. The robot considered in this work is an Agietron micro-nano (fig. 1), a parallel robot based

Floreano, Dario

392

Deposition of silicon-like hybrid films by PECVD on carbon-fiber-reinforced polymers for high-precision engineering  

E-print Network

over time. To improve long-term geometrical stability, hybrid silicon-like films have been depositedDeposition of silicon-like hybrid films by PECVD on carbon- fiber-reinforced polymers for high-precision engineering applications A Cremona1 , E Vassallo1 , A Merlo2 , A Srikantha Phani3 and L Laguardia1 1 Istituto

Phani, A. Srikantha

393

High-Precision In-situ Wavelength Stabilization and Monitoring of Tunable Lasers Using AWG and PD Arrays  

E-print Network

High-Precision In-situ Wavelength Stabilization and Monitoring of Tunable Lasers Using AWG and PD wavelength stabilization and monitoring technique based on a feedback loop using AWG with PD arrays at 0. In transmission systems, tunable laser often replaces fixed wavelength light source to simplify inventory issues

Kolner, Brian H.

394

High-precision image-drift-correction method for EM images with a low signal-to-noise ratio.  

PubMed

The phase correlation method (PCM) is well known for high-precision matching between images. However, if the signal-to-noise ratio of an image is low, the method is difficult to apply. To solve this problem, we developed an improved PCM that can match images automatically with sub-pixel matching precision. Using this method, a 0.2-nm crystal lattice spacing was clearly revealed after 10 blurred images were processed in a verification experiment; such a lattice could not be recognized or hardly be recognized in each individual image. PMID:24827157

Isakozawa, Shigeto; Tomonaga, Sachihiko; Hashimoto, Takahito; Baba, Norio

2014-08-01

395

Testing hypotheses about determinants of protein structure with high-precision, high-throughput stability measurements and statistical modeling.  

PubMed

Statistical modeling provides the mathematics to use data from large numbers of mutant proteins to generate information about hypotheses concerning protein structure not easily obtained from anecdotal studies on small numbers of mutants. Here we use the unfolding free energies of 303 unique eglin c mutant proteins obtained from high-precision, high-throughput chemical denaturation measurements to assess models concerning helix stability. A model with helix propensity as the sole determinant of stability accounts for 83% of the mutant-to-mutant variation in stability for 99% of the mutant proteins (three outliers). When position effects and side chain-side chain interactions are added to the model, the fraction of variation explained increases to 92%. The propensity parameters in this model are identical to helix propensity values derived from other approaches. Measurement error accounts for another 1% of the mutant-to-mutant variation in stability. While the data support terms for several of the expected stabilizing/destabilizing effects, it does not support terms for several others, including i, i + 3 effects in the center of the helix and helix-dipole effects. In addition, the model does better with terms for several stabilizing/destabilizing effects for which we cannot identify the physical basis. The precision of our unfolding stability measurements (+/-0.087 kcal/mol) allows us to conclude that the 7% of variation in stabilities of the mutant proteins not accounted for by the model or by measurement variation is both real and large with respect to the nonpropensity terms in the model. The analysis also shows that the common practice of using C(m)m(av) instead of C(m)m(mut) to calculate DeltaG(HOH,N-D) values for each mutant protein results in a loss of information. We see no correlation between the residuals derived from the full model and m(mut) - m(wt), and hence it is unlikely our m(mut) values reflect mutant-to-mutant differences in the denatured state. PMID:12809516

Yi, Fang; Sims, Dorothy A; Pielak, Gary J; Edgell, Marshall Hall

2003-06-24

396

High-precision measurement of the atomic mass of the electron  

NASA Astrophysics Data System (ADS)

The quest for the value of the electron's atomic mass has been the subject of continuing efforts over the past few decades. Among the seemingly fundamental constants that parameterize the Standard Model of physics and which are thus responsible for its predictive power, the electron mass me is prominent, being responsible for the structure and properties of atoms and molecules. It is closely linked to other fundamental constants, such as the Rydberg constant R? and the fine-structure constant ? (ref. 6). However, the low mass of the electron considerably complicates its precise determination. Here we combine a very precise measurement of the magnetic moment of a single electron bound to a carbon nucleus with a state-of-the-art calculation in the framework of bound-state quantum electrodynamics. The precision of the resulting value for the atomic mass of the electron surpasses the current literature value of the Committee on Data for Science and Technology (CODATA) by a factor of 13. This result lays the foundation for future fundamental physics experiments and precision tests of the Standard Model.

Sturm, S.; Köhler, F.; Zatorski, J.; Wagner, A.; Harman, Z.; Werth, G.; Quint, W.; Keitel, C. H.; Blaum, K.

2014-02-01

397

High-precision optical measurements of 13 isotope ratios in organic compounds at  

E-print Network

-precision isotope ratios are special-purpose isotope-ratio mass spectrometers (IRMS) (2, 3) that are fairly costly accuracy for methane, ethane, and propane is within 3 of the values determined using isotope ratio mass; however, it should be noted that the isotopes of hydrogen, nitrogen, oxygen, and sulfur have also been

Zare, Richard N.

398

High precision Zernike modal gray map reconstruction for liquid crystal corrector  

Microsoft Academic Search

This paper proposes a new Zernike modal gray map reconstruction algorithm used in the nematic liquid crystal adaptive optics system. Firstly, the new modal algorithm is described. Secondly, a single loop correction experiment was conducted, and it showed that the modal method has a higher precision in gray map reconstruction than the widely used slope method. Finally, the contrast close-loop

Chao Liu; Quan-Quan Mu; Li-Fa Hu; Zhao-Liang Cao; Li Xuan

2010-01-01

399

Some Factors Influencing the Life and Performance Reliability of High-Precision Potentiometers.  

National Technical Information Service (NTIS)

The study was conducted on a number of linear precision potentiometers of the type used in Navy computer systems which had been subjected to life testing by a Navy contractor. One manufacturer had used oil as the contact-arm and winding lubricant; the oth...

V. G. FitzSimmons, J. B. Romans

1965-01-01

400

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

Microsoft Academic Search

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

Aurélie Kapusta; Atsushi Matsuda; Antoine Marmignon; Michael Ku; Aude Silve; Eric Meyer; James D. Forney; Sophie Malinsky; Mireille Bétermier

2011-01-01

401

Designing a Calorimeter for High Precision Estimation of Specific Heat using Bayesian Inference  

Microsoft Academic Search

A standard approach to measuring specific heat is the placing of a sample in a bath of liquid and mea- suring the temperature change of the bath and the sample. The precision of the resulting estimate of the specific heat is directly dependent upon the accuracy with which the heat loss is known, a complex func- tion of the thermal

A. F. Emery

402

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

E-print Network

. Stratified radiocarbon samples and artifacts were recorded with precise digital surveying tools linked data with innovative visualization tools. The new radiocarbon dates push back by 2 centuries was characterized by an almost literal interpretation of the Old Testament (Hebrew Bible, HB) as historical fact

Schulze, Jürgen P.

403

Capacitive integration to produce high precision isotope ratio measurements on methyl chloride and methyl bromide  

Microsoft Academic Search

A capacitive integration circuit for the measurement of ion current ratios in an isotope ratio mass spectrometer is described. Sources of error and their effect on measurement precision are discussed. Results from the isotopic analysis of methyl chloride and of methyl bromide gases are presented. The relative standard deviation of measured ratios for methyl chloride was 13 parts in 10⁶

John F. Willey; James W. Taylor

1978-01-01

404

High precision measurement of undulator polarization in the regime of hard x-rays  

NASA Astrophysics Data System (ADS)

We have measured the polarization purity of undulator radiation at 12.9 keV, with hitherto unachievable precision. We could measure a polarization purity of 1.8 × 10-4 by using a silicon channel-cut crystal with six Bragg reflections at 45° as analyzer.

Marx, B.; Schulze, K. S.; Uschmann, I.; Kämpfer, T.; Wehrhan, O.; Wille, H. C.; Schlage, K.; Röhlsberger, R.; Weckert, E.; Förster, E.; Stöhlker, T.; Paulus, G. G.

2014-07-01

405

HOTB: High precision parallel code for calculation of four-particle harmonic oscillator transformation brackets  

NASA Astrophysics Data System (ADS)

This new version of the HOTB program for calculation of the three and four particle harmonic oscillator transformation brackets provides some enhancements and corrections to the earlier version (Germanas et al., 2010) [1]. In particular, new version allows calculations of harmonic oscillator transformation brackets be performed in parallel using MPI parallel communication standard. Moreover, higher precision of intermediate calculations using GNU Quadruple Precision and arbitrary precision library FMLib [2] is done. A package of Fortran code is presented. Calculation time of large matrices can be significantly reduced using effective parallel code. Use of Higher Precision methods in intermediate calculations increases the stability of algorithms and extends the validity of used algorithms for larger input values. Catalogue identifier: AEFQ_v4_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEFQ_v4_0.html Program obtainable from: CPC Program Library, Queen’s University of Belfast, N. Ireland Licensing provisions: GNU General Public License, version 3 Number of lines in programs, including test data, etc.: 1711 Number of bytes in distributed programs, including test data, etc.: 11667 Distribution format: tar.gz Program language used: FORTRAN 90 with MPI extensions for parallelism Computer: Any computer with FORTRAN 90 compiler Operating system: Windows, Linux, FreeBSD, True64 Unix Has the code been vectorized of parallelized?: Yes, parallelism using MPI extensions. Number of CPUs used: up to 999 RAM(per CPU core): Depending on allocated binomial and trinomial matrices and use of precision; at least 500 MB Catalogue identifier of previous version: AEFQ_v1_0 Journal reference of previous version: Comput. Phys. Comm. 181, Issue 2, (2010) 420-425 Does the new version supersede the previous version? Yes Nature of problem: Calculation of matrices of three-particle harmonic oscillator brackets (3HOB) and four-particle harmonic oscillator brackets (4HOB) in a more effective way, which allows us to calculate matrix of the brackets up to a few hundred times more rapidly and more accurate than in a previous version. Solution method: Using external parallelization libraries and mutable precision we created a pack of numerical codes based on the methods of compact expressions of the three and four-particle harmonics oscillator brackets 3HOB, 4HOB, presented in [3]. Restrictions: For double precision version calculations can be done up to harmonic oscillator (HO) energy quanta e=28. For quadruple precision mantissa is equal to approximately 34 decimal digits, therefore calculations can be done up to HO energy quanta to e=52. Running time: The running time depends on the harmonic oscillator energy quanta, cluster size and the precision of intermediate calculations. More information on Table 1 for 3HOB and Table 2 for 4HOB. Reasons for a new version: The new program version expands the limits of harmonic oscillator energy quanta and gives shorter calculation time. Extend the limits of calculation of HOB First version was able to produce harmonic oscillator transformation brackets for three and four particles if E?HO energy quanta. With this version of our program, if quadruple or arbitrary precision functions are being used, it is possible to calculate three and four particle harmonic oscillator transformation brackets for greater values of energy and momenta, while sustaining tolerable margin of error. Calculation time As the code of previous version of program was redone using parallelism paradigma, it is now possible to reduce the calculation time of transformation matrices significantly, depending on the size of computing cluster, as the dimensions of matrices are growing very rapidly according to the energy and momenta values. subroutinematrix_4HOB_dimensionCalculates the dimension of 4HOB matrix. subroutinematrix_3HOB_dimensionCalculates the dimension of 3HOB matrix, subroutinematrix_3HOBCalculates the global state array which is used in parallel calculation of 3HOB matrix. subroutinematrix_4HOBCalculates the global sta

Stepšys, A.; Mickevicius, S.; Germanas, D.; Kalinauskas, R. K.

2014-11-01

406

Development of a mobile and high-precision atmospheric CO2 monitoring station  

NASA Astrophysics Data System (ADS)

Nowadays one of the most burning questions for the science is the rate and the reasons of the recent climate change. Greenhouse gases (GHG), mainly CO2 and CH4 in the atmosphere could affect the climate of our planet. However, the relation between the amount of atmospheric GHG and the climate is complex, full with interactions and feedbacks partly poorly known even by now. The only way to understand the processes, to trace the changes, to develop and validate mathematical models for forecasts is the extensive, high precision, continuous monitoring of the atmosphere. Fossil fuel CO2 emissions are a major component of the European carbon budget. Separation of the fossil fuel signal from the natural biogenic one in the atmosphere is, therefore, a crucial task for quantifying exchange flux of the continental biosphere through atmospheric observations and inverse modelling. An independent method to estimate trace gas emissions is the top-down approach, using atmospheric CO2 concentration measurements combined with simultaneous radiocarbon (14C) observations. As adding fossil fuel CO2 to the atmosphere, therefore, leads not only to an increase in the CO2 content of the atmosphere but also to a decrease in the 14C/12C ratio in atmospheric CO2. The ATOMKI has more than two decade long experience in atmospheric 14CO2 monitoring. As a part of an ongoing research project being carried out in Hungary to investigate the amount and temporal and spatial variations of fossil fuel CO2 in the near surface atmosphere we developed a mobile and high-precision atmospheric CO2 monitoring station. We describe the layout and the operation of the measuring system which is designed for the continuous, unattended monitoring of CO2 mixing ratio in the near surface atmosphere based on an Ultramat 6F (Siemens) infrared gas analyser. In the station one atmospheric 14CO2 sampling unit is also installed which is developed and widely used since more than one decade by ATOMKI. Mixing ratio of CO2 is measured at 2 m above the ground by the monitoring station. Air is pumped through a 9.5-mm-diameter plastic tube (PFA, Swagelok) to a CO2 analyser located in a container box. Container box (Containex) is 1.5 m wide, 1.2 m deep and 2.2 m high, designed as a mobile measuring room which is field deployable, only electric power is required. A 15 micron pore size stainless steel Tee-Type (Swagelok) particle filter is located at the inlet of the sampler tube. Diaphragm pump (KNF) is used to draw air continuously through the sampling tube from monitoring level at flow rate of ~ 2 L/min. After leaving the pump, the air at 5 psig overpressure enters a glass trap for liquid water that is cooled in a regular household refrigerator, to dry the air to a dew point of 3°-4°C. Liquid water is forced out through an orifice at the bottom of the trap. The air sample inlet tube and the standard gases (Linde Hungary) are connected to miniature solenoid valves (S Series, ASCO Numatics) in a manifold which are normally closed and controlled by the CO2 analyser, which selects which gas is sampled. The air leaving the manifold through its common outlet is further dried to a dew point of about -25°C by passage through a 360-cm-long Nafion drier (Permapure), so that the water vapour interference and dilution effect are <0.1 ppm equivalent CO2. The Nafion drier is purged in a counter flow (300 cm3/min) arrangement using waste sample air that has been further dried by passage through anhydrous CaSO4 (Drierite). Analysis is carried out using an infrared gas analyser Ultramat 6F which is a specialised model for field applications by Siemens. A constant sample flow rate of 300 cm3/min is maintained by a mass flow controller (Aalborg). The reference cell of the CO2 analyzer is continuously flushed with a compressed reference gas of 350 ppm CO2 in synthetic air (Messer Hungarogáz). The basic calibration cycle is 2 hours, consisting of a zero-point calibration and a span calibration. Each calibration is consisting of 2 min flushing and 20 sec signal integration. The usual change of the r

Molnár, M.; Haszpra, L.; Major, I.; Svingor, É.; Veres, M.

2009-04-01

407

Experimental study of trajectory planning and control of a high precision robot manipulator  

NASA Technical Reports Server (NTRS)

The kinematic and trajectory planning is presented for a 6 DOF end-effector whose design was based on the Stewart Platform mechanism. The end-effector was used as a testbed for studying robotic assembly of NASA hardware with passive compliance. Vector analysis was employed to derive a closed-form solution for the end-effector inverse kinematic transformation. A computationally efficient numerical solution was obtained for the end-effector forward kinematic transformation using Newton-Raphson method. Three trajectory planning schemes, two for fine motion and one for gross motion, were developed for the end-effector. Experiments conducted to evaluate the performance of the trajectory planning schemes showed excellent tracking quality with minimal errors. Current activities focus on implementing the developed trajectory planning schemes on mating and demating space-rated connectors and using the compliant platform to acquire forces/torques applied on the end-effector during the assembly task.

Nguyen, Charles C.; Antrazi, Sami S.

1991-01-01

408

Trends in experimental high-energy physics  

SciTech Connect

Data from a scan of papers in Physical Review Letters and Physical Review are used to demonstrate that American high-energy physicists show a pattern of accelerator and instrumentation usage characteristic of that expected from the logistic-substitution model of Marchetti and of Fischer and Pry.

Sanford, T.W.L.

1982-06-01

409

High-precision gamma-ray total cross-section measurements between 3.45 and 12 MeV  

SciTech Connect

A Compton-backscatter capability has recently become available at the Duke University Free Electron Laser Laboratory. This capability allows one to produce high fluxes of tunable, nearly monoenergetic gamma rays. Using these gamma-ray beams, we have made high-precision (~0.5%) measurements of the gamma-ray total cross section at 3.45, 4, 5, 6, 8, 10, and 12 MeV. The nuclei measured were Be, C, Cu, Ta, W, Pb, and U

Frankle, Christen M.; Moss, Calvin E.

2008-12-01

410

Portable, high intensity isotopic neutron source provides increased experimental accuracy  

NASA Technical Reports Server (NTRS)

Small portable, high intensity isotopic neutron source combines twelve curium-americium beryllium sources. This high intensity of neutrons, with a flux which slowly decreases at a known rate, provides for increased experimental accuracy.

Mohr, W. C.; Stewart, D. C.; Wahlgren, M. A.

1968-01-01

411

STEP mission: high-precision space astrometry to search for terrestrial exoplanets  

NASA Astrophysics Data System (ADS)

Search for Terrestrial Exo-Planest (hereafter STEP) mission is a latest advanced research project in Chinese Strategic Pioneer Program (SPP) on Space Science. STEP aims at the nearby earth-alike planets detection, comprehensive research on the planetary system and some astrometry research with 1 micro-arcsecond precision in the space, which will get the fruitful achievements in the exo-planetary and astrometry research fields. STEP will take the Space Astrometry technique in the optical band. The FOV is 0.44 degree, based on 1.2 m primary and focus length is 50 m. The special metrology technique will be taken to reach 0.5 ~ 1 uas astrometry precision, which will be ideal for terrestrial exo-planets detection.

Chen, D.

2014-04-01

412

Highly-precise measurements of ambient oxygen using near-infrared cavity-enhanced laser absorption spectrometry.  

PubMed

Highly precise measurements of ambient oxygen have been used to constrain the carbon budget, study photosynthesis, estimate marine productivity, and prescribe individual pollution events to their point of origin. These studies require analyzers that can measure ambient oxygen with ppm-level precision. In this work, we utilize near-infrared off-axis integrated cavity output spectroscopy (off-axis ICOS) to quantify ambient oxygen with a precision (1?, 100s) of ±7 ppm. By periodically calibrating the instrument, the analyzer is capable of making oxygen measurements to better than ±1 ppm (1?). The sensor is highly linear (R(2) > 0.9999) over a wide dynamic range (0-100% oxygen). The sensor was combined with a commercial CO(2)/CH(4)/H(2)O Analyzer, and used to make measurements of respiration and fossil fuel pollution events with oxidative ratios ranging from 1.15-1.60. Future improvements will increase the analyzer precision (1?, 100s) to better than ±1.4 ppm, and decrease the periodic referencing interval to >1 h. By including an additional diode laser, the instrument can be extended to make simultaneous measurements of O(2), CO(2), and H(2)O to enable improved understanding of carbon dioxide production and loss. PMID:22924385

Gupta, Manish

2012-09-18

413

Two recent high-precision determinations of {alpha}{sub s}  

SciTech Connect

The two highest precision determinations of {alpha}{sub s}(M{sub Z}{sup 2}), that based on the analysis of short-distance-sensitive lattice observables, and that based on an analysis of hadronic {tau} decay data, have, until recently, yielded results differing by {approx}3{sigma}. I review recent updates which bring the two determinations into excellent agreement, and discuss prospects for additional future improvements.

Maltman, Kim [Math and Stats, York Univ., 4700 Keele St., Toronto ON M3J 1P3 (Canada) and CSSM, Univ. of Adelaide, Adelaide SA 5005 Australia

2010-07-27