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Review of Scientific Instruments

Yung-Tsung Cheng, Cheng-Chi Tai, Willy Chou, Shih-Tsang Tang, Jiun-Hung Lin
The advance of modern medical technology has extended people's life and increased the average age of the society. Some chronic diseases are due to the aging of the population and knee joint aging is a common disease in the elderly. Common joint pathology contains degenerative arthritis, arthroncus of knees, and gouty arthritis. Knee joints are the largest and the most complicated joints in a human body as well as the joint bearing huge pressure. Wrong posture, overuse, or vigorous exercise often cause injuries to knee joints, and such injuries could easily result in joint pathology and patients falling and breaking bones due to pain and powerlessness...
August 2018: Review of Scientific Instruments
P Molina Cabrera, S Coda, L Porte, N Offeddu, P Lavanchy, M Silva, M Toussaint
A variable configuration V-band heterodyne Doppler back-scattering diagnostic has been recently made operational in the tokamak <mml:math xmlns:mml=""> <mml:mrow> <mml:mover> <mml:mrow> <mml:mtext>a</mml:mtext> </mml:mrow> <mml:mo>̀</mml:mo> </mml:mover> </mml:mrow> </mml:math> configuration variable. This article describes the hardware setup options, flexible quasi-optical launcher antenna, data-analysis techniques, and first data...
August 2018: Review of Scientific Instruments
Tongju Wang, Jian Lin, Xingye Guo, Yongping Lei, Hanguang Fu
Droplets produced by continuous-ink-jet printing are widely used in various fields. The gas pressure in the feedstock tank and the perturbation imposed on a capillary jet are the primary parameters to control the formation process of the droplets. However, the lack of a simple method for producing perturbation is a major limitation of continuous-ink-jet technology. Therefore, based on the technology of electromagnetic force perturbation, a novel and simple system to produce the desired perturbation frequency is constructed in this article...
August 2018: Review of Scientific Instruments
Andrew L Cooper, K J Kelly, E Machado, I Pogrebnyak, J Surbrook, C Tysor, P Thompson, M Emamian, B Walsh, B Carlin, J R Dermigny, A E Champagne, T B Clegg
The primary challenge in directly measuring nuclear reaction rates near stellar energies is their small cross sections. The signal-to-background ratio in these complex experiments can be significantly improved by employing high-current (mA-range) beams and novel detection techniques. Therefore, the electron cyclotron resonance ion source at the Laboratory for Experimental Nuclear Astrophysics underwent a complete upgrade of its acceleration column and microwave system to obtain high-intensity, pulsed proton beams...
August 2018: Review of Scientific Instruments
C Goyon, P S Datte, J G Buscho, N J Butler, J E Hernandez, M Hohenberger, B L Lechleiter, P Michel, J S Ross, P M Bell, J D Moody
Supra-thermal (>100 keV) electrons generated by laser plasma interactions can be detrimental to the performance of ignition experiments conducted on the National Ignition Facility (NIF). On a NIF shot, the amount of electrons is estimated by measuring the hard X-rays passing through the hohlraum wall. The primary sources of hot electrons in a hohlraum are Stimulated Raman Scattering (SRS) and two plasmon decay (TPD). While SRS is well diagnosed on the NIF, there has been no diagnosis of TPD. We have designed and implemented a new diagnostic to characterize the time history of TPD on the NIF...
August 2018: Review of Scientific Instruments
Chuhyun Cho, Yun-Sik Jin
High-voltage, repetitive pulse generation technology plays a key role in underwater discharge applications such as water treatment and metal nanocolloid production. For these applications, a high-voltage, high-speed switching technology was crucial to swiftly transfer the energy stored in the capacitor to the electrodes in water. A rotary-triggered double spark gap switch was developed for this purpose in this study. Two spark gaps dedicated for charge and discharge were arranged in this switch, and they eliminated the irregular and unstable pulse generation due to the simultaneous charging and discharging in the pulse-generating circuits...
August 2018: Review of Scientific Instruments
Atsushi Miyagi, Simon Scheuring
In any atomic force microscope operated in amplitude modulation mode, aka "tapping mode" or "oscillating mode," the most crucial operation is the detection of the cantilever oscillation amplitude. Indeed, it is the change in the cantilever oscillation amplitude that drives the feedback loop, and thus, the accuracy and speed of amplitude detection are of utmost importance for improved atomic force microscopy operation. This becomes even more crucial for the operation of a high-speed atomic force microscope (HS-AFM), where feedback operation on a single or a low number of cantilever oscillation cycles between 500 kHz and 1000 kHz oscillation frequency is desired...
August 2018: Review of Scientific Instruments
Jan Balajka, Jiri Pavelec, Mojmir Komora, Michael Schmid, Ulrike Diebold
The structure of the solid-liquid interface often defines the function and performance of materials in applications. To study this interface at the atomic scale, we extended an ultrahigh vacuum (UHV) surface-science chamber with an apparatus that allows bringing a surface in contact with ultrapure liquid water without exposure to air. In this process, a sample, typically a single crystal prepared and characterized in UHV, is transferred into a separate, small chamber. This chamber already contains a volume of ultrapure water ice...
August 2018: Review of Scientific Instruments
Daniel Schönke, Andreas Oelsner, Pascal Krautscheid, Robert M Reeve, Mathias Kläui
Scanning electron microscopy with polarization analysis is a powerful lab-based magnetic imaging technique offering simultaneous imaging of multiple magnetization components and a very high spatial resolution. However, one drawback of the technique is the long required acquisition time resulting from the low inherent efficiency of spin detection, which has limited the applicability of the technique to certain quasi-static measurement schemes and materials with high magnetic contrast. Here we demonstrate the ability to improve the signal-to-noise ratio for particular classes of measurements involving periodic excitation of the magnetic structure via the implementation of a digital phase-sensitive detection scheme facilitated by the integration of a time-to-digital converter to the system...
August 2018: Review of Scientific Instruments
T H Jones, J Javor, E K Sequin, J D West, S Prakash, V V Subramaniam
We present a method for designing and optimizing an in-house designed electromagnetic probe for distinguishing morphological differences in biological tissues. The probe comprises concentric multi-wound coils, the inner being the primary coil and the outer being the detector coil. A time-varying voltage is imposed on the primary coil, resulting in an induced current in the detector coil. For highly conductive samples, eddy currents are induced in the sample and inductively couple with the electromagnetic probe...
August 2018: Review of Scientific Instruments
Dhruv Singhal, Jessy Paterson, Dimitri Tainoff, Jacques Richard, Meriam Ben-Khedim, Pascal Gentile, Laurent Cagnon, Daniel Bourgault, Denis Buttard, Olivier Bourgeois
The 3 ω method is a dynamic measurement technique developed for determining the thermal conductivity of thin films or semi-infinite bulk materials. A simplified model is often applied to deduce the thermal conductivity from the slope of the real part of the ac temperature amplitude as a function of the logarithm of frequency, which in-turn brings a limitation on the kind of samples under observation. In this work, we have measured the thermal conductivity of a forest of nanowires embedded in nanoporous alumina membranes using the 3 ω method...
August 2018: Review of Scientific Instruments
A D Sladkomedova, A G Alekseev, N N Bakharev, V K Gusev, N A Khromov, G S Kurskiev, V B Minaev, M I Patrov, Yu V Petrov, N V Sakharov, P B Shchegolev, V V Solokha, A Yu Telnova, S Yu Tolstyakov, V V Zabrodsky
A diagnostic system for plasma radiated power tomography on Globus-M was upgraded with a new linear array based on silicon photodiodes. The hardware of the diagnostic system based on a 256-channel tangential matrix array and a 24-channel linear array is described. The algorithm for 2D tomographic reconstruction of plasma emissivity is presented. It uses the Tikhonov regularization method and anisotropic diffusion functional as a side constraint. Simulated plasma emissivity profiles were used to test and assess the capabilities of the developed algorithm...
August 2018: Review of Scientific Instruments
L J Devlin, L B Jones, T C Q Noakes, C P Welsch, B L Militsyn
The Transverse Energy Spread Spectrometer (TESS) was designed primarily to study the mean transverse energy spread of electrons emitted from photocathode electron sources at both room and liquid nitrogen temperatures as a function of quantum efficiency through analysis of the photoemission footprint. By reconfiguring the potentials applied to different detector elements, TESS can also be used to measure the mean longitudinal energy spread of photoemitted electrons. Initial plans were to use electrostatic wire meshes as a retarding element which prevents the detection of electrons with insufficient energy to overcome a variable potential barrier...
August 2018: Review of Scientific Instruments
Pavel Trojanek, Ivan Prochazka
We are reporting on time transfer parameters of a newly presented method of the Two-Way Time Transfer (TWTT) using the single photon counting approach. The method utilizes two Single Photon Avalanche Diode (SPAD) detectors located on both ends of the optical channel. Each of the SPAD detectors measures the common signal taken from both communication directions on its location. The mixed signal is then mathematically decomposed back to the original, separated signals, whose time shifts are then measured, and the absolute time shift of the two distant time scales is calculated...
August 2018: Review of Scientific Instruments
Mehmet Cihat Ozgenel
With the reduction of magnet costs and the production of high-energy magnets in small sizes, permanent magnet brushless motors are used widely in various applications from household to medical, industrial, and automation applications. Furthermore, permanent magnet brushless motors have some significant advantages over the other conventional motors such as induction and brushed motors. Due to the popularity of brushless motors, they have become the focus of interest of researchers. From the past 30 years to today, the researchers have carried out numerous studies in relation to brushless motors...
August 2018: Review of Scientific Instruments
Jingxin Zhu, Xiong Shen, Lei Lin, Zhe Si, Jun Liu
A compact and alignment-free device based on transient grating self-referenced spectral interferometry is proposed to realize the temporal profile measurement of femtosecond laser pulses. The entire optical setup is composed of two lenses and two glass plates on a straight line with tubes, thereby avoiding complicated optical alignment and improving the stability and practicality of the device. Two 51.0 fs and 16.9 fs laser pulses at 800 nm and a 60.6 fs pulse at 1800 nm are all successfully measured by this device, which verifies the reliability of the device...
August 2018: Review of Scientific Instruments
Ziying Zhang, Xi Zhang, Panpan Zhang, Fengbiao Wu, Xuehui Li
Local mean decomposition (LMD) is a self-adaptive method, which has been widely applied to extract early fault signals from bearings. However, mode mixing occurs during the decomposition process. Moreover, in processing signals with strong noise, false frequency components can be generated by variational mode decomposition (VMD). To address these problems, a weak fault extraction method based on VMD is proposed for rolling bearings. This method regards LMD and the combination production function (CPF) as prefilters for VMD...
August 2018: Review of Scientific Instruments
Mohammadreza Shahzadeh, Mizanur Rahman, Olav Hellwig, Simone Pisana
In this work, we present the implementation of a new method to perform high-frequency thermoreflectance measurements on thin films. The so-called differential broad-band frequency domain thermoreflectance method follows broad-band frequency domain thermoreflectance developed previously [Regner et al. , Rev. Sci. Instrum. 84 (6), 064901 (2013)], without the use of expensive electro-optic modulators. Two techniques are introduced to recover the thermal phase of interest and to separate it from the unwanted instrumental contributions to the recorded phase...
August 2018: Review of Scientific Instruments
Liang Li, Yifei Liu, Longwei Chen, Gong Wang, Ming Liu, Zhaoxing Ren, Ying Zhao, Bingshan Liu, Guangheng Zhao
Under ultra-low pressure, an electron beam is generated by the microwave electron cyclotron resonance plasma with a permanent magnet. By means of the Hall coil and Miller ampere meter, two electron current signals at the end of the extraction anode (Ia) and the sample holder (Is) were measured. The influences of discharge power, gas pressure, and accelerating voltage on the electron beam current Is were analyzed. The experimental results indicated that the extracted electron current can reach 75.1 mA at a gas pressure of 1...
August 2018: Review of Scientific Instruments
Krzysztof Tyszka, Marek Dobosz
To increase the laser beam pointing stability required for precise interferometric measurements, we designed an active laser beam angular stabilization system. We used two recently proposed techniques: an interferometric measurement method of laser beam angular deflection which allows compact sensor design and a double wedge-prism beam deflector for precise laser beam steering. Our system provides long-term angular stabilization independently in the horizontal and the vertical planes, providing a hundredfold reduction of the output beam deviations...
August 2018: Review of Scientific Instruments
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