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Review of Scientific Instruments

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https://www.readbyqxmd.com/read/28571473/an-interferometric-system-for-measuring-thickness-of-parallel-glass-plates-without-2%C3%AF-ambiguity-using-phase-analysis-of-quadrature-haidinger-fringes
#1
Jong-Ahn Kim, Jae Wan Kim, Chu-Shik Kang, Jonghan Jin, Jae Yong Lee
An interferometric system is proposed for measuring the thickness of parallel glass plates by analyzing Haidinger fringes. Although a conventional Haidinger interferometer can measure thickness without 2π ambiguity using positions of peak and valley points in the interferogram, measurement accuracy is directly affected by the number of these points involved in the calculation. The proposed method obtains phase values over the entire interferogram by analyzing the quadrature Haidinger fringes generated by a current modulated laser diode...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571472/a-compact-multi-wire-layered-secondary-winding-for-tesla-transformer
#2
Liang Zhao, Jian-Cang Su, Rui Li, Xiao-Long Wu, Xiu-Dong Xu, Xu-Dong Qiu, Bo Zeng, Jie Cheng, Yu Zhang, Peng-Cheng Gao
A compact multi-wire-layered (MWL) secondary winding for a Tesla transformer is put forward. The basic principle of this winding is to wind the metal wire on a polymeric base tube in a multi-layer manner. The tube is tapered and has high electrical strength and high mechanical strength. Concentric-circle grooves perpendicular to the axis of the tube are carved on the surface of the tube to wind the wire. The width of the groove is basically equal to the diameter of the wire so that the metal wire can be fixed in the groove without glue...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571471/imaging-at-an-x-ray-absorption-edge-using-free-electron-laser-pulses-for-interface-dynamics-in-high-energy-density-systems
#3
M A Beckwith, S Jiang, A Schropp, A Fernandez-Pañella, H G Rinderknecht, S C Wilks, K B Fournier, E C Galtier, Z Xing, E Granados, E Gamboa, S H Glenzer, P Heimann, U Zastrau, B I Cho, J H Eggert, G W Collins, Y Ping
Tuning the energy of an x-ray probe to an absorption line or edge can provide material-specific measurements that are particularly useful for interfaces. Simulated hard x-ray images above the Fe K-edge are presented to examine ion diffusion across an interface between Fe2O3 and SiO2 aerogel foam materials. The simulations demonstrate the feasibility of such a technique for measurements of density scale lengths near the interface with submicron spatial resolution. A proof-of-principle experiment is designed and performed at the Linac coherent light source facility...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571470/choosing-the-filter-for-catenary-image-enhancement-method-based-on-the-non-subsampled-contourlet-transform
#4
Changdong Wu, Zhigang Liu, Hua Jiang
The quality of image enhancement plays an important role in the catenary fault diagnosis system based on the image processing technique. It is necessary to enhance the low contrast image of catenary for better detecting the state of catenary part. The Non-subsampled Contourlet transform (NSCT) is the improved Contourlet transform (CT), which can effectively solve the problem of artifact phenomenon in the enhanced catenary image. Besides, choosing the enhancement function and the filter of the NSCT will directly influence the image enhancement effect...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571469/robust-regression-and-its-application-in-absolute-gravimeters
#5
M Hu, W M Zhang, M Zhong
Maximum-likelihood estimation of robust regression is employed to process absolute gravimeter data because this method is insensitive to outliers. Gravity values obtained by both ordinary least squares and different approaches for robust regression are compared with the results obtained by the g9 processing software for the FG5 gravimeter. The results show that the accuracy of gravity data can be improved by rejecting certain outliers via adjustments to a suitable weighting function of time-distance pairs. A convenient method of identifying those outliers by their weight is also presented...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571468/radar-for-tracer-particles
#6
Felix Ott, Stephan Herminghaus, Kai Huang
We introduce a radar system capable of tracking a 5 mm spherical target continuously in three dimensions. The 10 GHz (X-band) radar system has a transmission power of 1 W and operates in the near field of the horn antennae. By comparing the phase shift of the electromagnetic wave traveling through the free space with an IQ-mixer, we obtain the relative movement of the target with respect to the antennae. From the azimuth and inclination angles of the receiving antennae obtained in the calibration, we reconstruct the target trajectory in a three-dimensional Cartesian system...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571467/acoustic-spectrometer-with-minimized-background-dissipation
#7
D Driaev, A Iashvili, L Kankadze, S Tsakadze
Apparatus for measurements of internal friction from Q(-1)∼10(-6) and elastic moduli in the kilohertz frequency range in which external friction losses were minimized using a new-type of three-reed tuning fork as a sample under study is described. High sensitivity of the apparatus made it possible to observe a resonance plasticization of diamagnetic LiF crystals under the action of crossed magnetic fields (≈100 μT) in the EPR conditions.
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571466/localized-thin-film-damage-sourced-and-monitored-via-pump-probe-modulated-thermoreflectance
#8
Brian F Donovan, John A Tomko, Ashutosh Giri, David H Olson, Jeffrey L Braun, John T Gaskins, Patrick E Hopkins
Damage in the form of dewetting and delamination of thin films is a major concern in applications requiring micro- or nano-fabrication. In non-contact nanoscale characterization, optical interrogation must be kept to energies below damage thresholds in order to conduct measurements such as pump-probe spectroscopy. In this study, we show that the thermoreflectance of thin films can indicate the degree of film damage induced by a modulated optical heating source. By adjusting the absorbed power of the pump heating event, we identify the characteristics of the change in the thermoreflectance signal when leading up to and exceeding the damage threshold of gold films of varying thicknesses on glass substrates...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571465/a-high-flux-upgrade-for-the-brisp-spectrometer-at-ill
#9
M Zanatta, F Barocchi, A De Francesco, E Farhi, F Formisano, E Guarini, A Laloni, A Orecchini, A Paciaroni, C Petrillo, W-C Pilgrim, J-B Suck, F Sacchetti
To date, the BRISP spectrometer represents the state-of-the-art for every instrument aiming to perform Brillouin neutron scattering. Exploiting accurate ray-tracing McStas simulations, we investigate an improved configuration of the BRISP primary spectrometer to provide a higher flux at the sample position, while preserving all the present capabilities of the instrument. This configuration is based on a neutron guide system and is designed to fit the instrument platform with no modifications of the secondary spectrometer...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571464/apparatus-and-test-method-for-characterizing-the-temperature-regulating-properties-of-thermal-functional-porous-polymeric-materials
#10
Bao-Guo Yao, Shan Zhang, De-Pin Zhang
In order to evaluate the temperature regulating properties of thermal functional porous polymeric materials such as fabrics treated with phase change material microcapsules, a new apparatus was developed. The apparatus and the test method can measure the heat flux, temperature, and displacement signals during the dynamic contact and then quickly give an evaluation for the temperature regulating properties by simulating the dynamic heat transfer and temperature regulating process when the materials contact the body skin...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571463/a-q-band-low-noise-gaas-phemt-mmic-power-amplifier-for-pulse-electron-spin-resonance-spectrometer
#11
A Sitnikov, E Kalabukhova, V Oliynyk, M Kolisnichenko
We present the design and development of a single stage pulse power amplifier working in the frequency range 32-38 GHz based on a monolithic microwave integrated circuit (MMIC). We have designed the MMIC power amplifier by using the commercially available packaged GaAs pseudomorphic high electron mobility transistor. The circuit fabrication and assembly process includes the elaboration of the matching networks for the MMIC power amplifier and their assembling as well as the topology outline and fabrication of the printed circuit board of the waveguide-microstrip line transitions...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571462/analysis-of-granular-packing-structure-by-scattering-of-thz-radiation
#12
Philip Born, Karsten Holldack
Scattering methods are widely used to characterize the structure and constituents of matter on small length scales. This motivates this introductory text on identifying prospective approaches to scattering-based methods for granular media. A survey to light scattering by particles and particle ensembles is given. It is elaborated why the established scattering methods using X-rays and visible light cannot in general be transferred to granular media. Spectroscopic measurements using terahertz radiation are highlighted as they probe the scattering properties of granular media, which are sensitive to the packing structure...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571461/positron-emission-particle-tracking-and-its-application-to-granular-media
#13
D J Parker
Positron emission particle tracking (PEPT) is a technique for tracking a single radioactively labelled particle. Accurate 3D tracking is possible even when the particle is moving at high speed inside a dense opaque system. In many cases, tracking a single particle within a granular system provides sufficient information to determine the time-averaged behaviour of the entire granular system. After a general introduction, this paper describes the detector systems (PET scanners and positron cameras) used to record PEPT data, the techniques used to label particles, and the algorithms used to process the data...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571460/correlative-imaging-across-microscopy-platforms-using-the-fast-and-accurate-relocation-of-microscopic-experimental-regions-farmer-method
#14
Toan Huynh, Matthew K Daddysman, Ying Bao, Alan Selewa, Andrey Kuznetsov, Louis H Philipson, Norbert F Scherer
Imaging specific regions of interest (ROIs) of nanomaterials or biological samples with different imaging modalities (e.g., light and electron microscopy) or at subsequent time points (e.g., before and after off-microscope procedures) requires relocating the ROIs. Unfortunately, relocation is typically difficult and very time consuming to achieve. Previously developed techniques involve the fabrication of arrays of features, the procedures for which are complex, and the added features can interfere with imaging the ROIs...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571459/an-experimental-setup-to-study-delayed-electron-emission-upon-photoexcitation-of-trapped-polyatomic-anions
#15
K Saha, A Prabhakaran, V Chandrasekaran, M L Rappaport, O Heber, D Zajfman
A Velocity Map Imaging (VMI) spectrometer has been designed and integrated with an electrostatic ion beam trap to study delayed electron emission from trapped polyatomic anions upon photodetachment. The VMI spectrometer is small in size and can record a wide range of photoelectron energies, with variable magnification. Delayed electron emission can be recorded in our experimental setup for any time duration after the photoexcitation of the polyatomic anions. Experiments were carried out with trapped O(-) and C5(-) ions to demonstrate the capability of the spectrometer...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571458/refractive-index-matched-scanning-and-detection-of-soft-particles
#16
Joshua A Dijksman, Nicolas Brodu, Robert P Behringer
We describe here how to apply the three-dimensional imaging technique of refractive index matched scanning to hydrogel spheres. Hydrogels are water based materials with a low refractive index, which allows for index matching with water-based solvent mixtures. We discuss here various experimental techniques required to handle specifically hydrogel spheres as opposed to other transparent materials. The deformability of hydrogel spheres makes their identification in three-dimensional images non-trivial. We will also discuss numerical techniques that can be used in general to detect contacting, non-spherical particles in a three-dimensional image...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571457/ion-cyclotron-resonance-heating-icrh-systems-for-the-keda-mirror-with-axisymmetry-kmax
#17
Ming Liu, Hongshen Yi, Munan Lin, Yanpeng Wang, Peiyun Shi, Jian Zheng, Xuan Sun
In this paper, we describe the engineering work involved in constructing two ion cyclotron resonance heating (ICRH) systems for use in the Keda Mirror with AXisymmetry tandem mirror experiment. Because they offer an effective and robust heating method, ICRH systems have been widely used in a variety of plasma experiments. The goal of our system is to heat the hydrogen plasma contained in the central cell using the fundamental ion cyclotron frequency. Both systems can deliver a radiofrequency power of ∼120 kW with adjustable operating frequencies that are tuned to be slightly lower than their local ion cyclotron frequencies...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571456/microchannel-plate-detector-detection-efficiency-to-monoenergetic-electrons-between-3-and-28-kev
#18
Ryan C Blase, Roland R Benke, Gregory P Miller, Keith S Pickens, J Hunter Waite
An unshielded microchannel plate (MCP) detector with an ultrafine pore diameter of 2 μm was irradiated by an electron beam to determine the detection efficiency of electrons for creating detector signals, or counts. Tested electron energies spanned a range of 3 kiloelectron volts (keV) to 28 keV. Higher detection efficiencies were measured at the lower end of this energy range, 0.376 counts per incident electron at 3 keV down to 0.155 at 15 keV with an increase to 0.217 at 18 keV and then another decrease down to 0...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571455/spatially-resolved-measurements-of-micro-deformations-in-granular-materials-using-diffusing-wave-spectroscopy
#19
Axelle Amon, Alesya Mikhailovskaya, Jérôme Crassous
This article is a tutorial on the practical implementation of a method of measurement of minute deformations based on multiple scattering. This technique has been recently developed and has proven to give new insights into the spatial repartition of strain in a granular material. We provide here the basics to understand the method by giving a synthetic review on diffusing wave spectroscopy and multiple scattering in granular materials. We detail a simple experiment using standard lab equipment to pedagogically demonstrate the implementation of the method...
May 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/28571454/a-frequency-modulated-continuous-wave-reflectometer-for-the-lithium-tokamak-experiment
#20
S Kubota, R Majeski, W A Peebles, R E Bell, D P Boyle, R Kaita, T Kozub, M Lucia, E Merino, X V Nguyen, T L Rhodes, J C Schmitt
The frequency-modulated continuous-wave reflectometer on LTX (Lithium Tokamak Experiment) and the data analysis methods used for determining electron density profiles are described. The diagnostic uses a frequency range of 13.1-33.5 GHz, for covering a density range of 0.21-1.4×10(13) cm(-3) (in O-mode polarization) with a time resolution down to 8 μs. The design of the diagnostic incorporates the concept of an "optimized" source frequency sweep, which minimizes the large variation in the intermediate frequency signal due to a long dispersive transmission line...
May 2017: Review of Scientific Instruments
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