Read by QxMD icon Read

Review of Scientific Instruments

P K Koo, S U Setru, S G J Mochrie
No abstract text is available yet for this article.
August 2016: Review of Scientific Instruments
Richard C Pardo
No abstract text is available yet for this article.
August 2016: Review of Scientific Instruments
Andreas Mandelis
No abstract text is available yet for this article.
August 2016: Review of Scientific Instruments
Dashan Zhang, Jie Guo, Xiujun Lei, Chang'an Zhu
This note reports an efficient singular value decomposition (SVD)-based vibration extraction approach that recovers sound information in silent high-speed video. A high-speed camera of which frame rates are in the range of 2 kHz-10 kHz is applied to film the vibrating objects. Sub-images cut from video frames are transformed into column vectors and then reconstructed to a new matrix. The SVD of the new matrix produces orthonormal image bases (OIBs) and image projections onto specific OIB can be recovered as understandable acoustical signals...
August 2016: Review of Scientific Instruments
Fan Zhu, Xinran Tan, Jiubin Tan, Zhigang Fan
An autocollimation (AC) setup with ultra-high resolution and stability for micro-angle measurement is presented. The telephoto objective, which is characterized in long focal length at a compact structure size, and the optical enlargement unit, which can magnify the image displacement to improve its measurement resolution and accuracy, are used to obtain an ultra-high measurement resolution of the AC. The common-path beam drift compensation is used to suppress the drift of measurement results, which is evident in the high-resolution AC, thus to obtain a high measurement stability...
August 2016: Review of Scientific Instruments
Na Li, Yu-Ping Wu, Hao Min, Tao Yang, Xiao Jiang
A radio-frequency (RF) source designed for cold atom experiments is presented. The source uses AD9858, a direct digital synthesizer, to generate the sine wave directly, up to 400 MHz, with sub-Hz resolution. An amplitude control circuit consisting of wideband variable gain amplifier and high speed digital to analog converter is integrated into the source, capable of 70 dB off isolation and 4 ns on-off keying. A field programmable gate array is used to implement a versatile frequency and amplitude co-sweep logic...
August 2016: Review of Scientific Instruments
Meng Li, Chunkai Xu, Panke Zhang, Zhean Li, Xiangjun Chen
We report a novel scanning probe electron energy spectrometer (SPEES) which combines a double toroidal analyzer with a scanning tunneling microscope to achieve both topography imaging and electron energy spectroscopy mapping of surface in situ. The spatial resolution of spectroscopy mapping is determined to be better than 0.7 ± 0.2 μm at a tip sample distance of 7 μm. Meanwhile, the size of the field emission electron beam spot on the surface is also measured, and is about 3.6 ± 0.8 μm in diameter. This unambiguously demonstrates that the spatial resolution of SPEES technique can be much better than the size of the incident electron beam...
August 2016: Review of Scientific Instruments
Long Hu, Jiancang Su, Zhenjie Ding, Qingsong Hao, Yajun Fan, Chunliang Liu
An all solid-state high repetitive sub-nanosecond risetime pulse generator featuring low-energy-triggered bulk gallium arsenide (GaAs) avalanche semiconductor switches and a step-type transmission line is presented. The step-type transmission line with two stages is charged to a potential of 5.0 kV also biasing at the switches. The bulk GaAs avalanche semiconductor switch closes within sub-nanosecond range when illuminated with approximately 87 nJ of laser energy at 905 nm in a single pulse. An asymmetric dipolar pulse with peak-to-peak amplitude of 9...
August 2016: Review of Scientific Instruments
P E Masherov, V A Riaby, V K Abgaryan
In an earlier publication, the ion mass determination technique was proposed using the Langmuir probe measurement results for low-pressure Maxwellian plasmas and their analysis, based on the Bohm effect and the Child-Boguslavsky-Langmuir (CBL) probe sheath model, allowing for probe sheath thickness and ion mass evaluations after the Bohm coefficient CBCyl ≈ 1.13 for cylindrical probes had been determined. In the present study, the step-front sheath model, being physically closer to the reality of gas discharge plasmas, was considered in order to correct the CBL sheath model results...
August 2016: Review of Scientific Instruments
C H Lan, J D Long, L Zheng, P Dong, Z Yang, J Li, T Wang, J L He
Axial symmetry of discharge is very important for application of vacuum arc plasma. It is discovered that the triggering method is a significant factor that would influence the symmetry of arc discharge at the final stable stage. Using high-speed multiframe photography, the transition processes from cathode-trigger discharge to cathode-anode discharge were observed. It is shown that the performances of the two triggering methods investigated are quite different. Arc discharge triggered by independent electric source can be stabilized at the center of anode grid, but it is difficult to achieve such good symmetry through resistance triggering...
August 2016: Review of Scientific Instruments
Ye Tao, Liping Yang, Qiu Zhong, Zijun Xu, Caiyun Luo
A data correction method that can reduce finite pulse time effects in the flash method is presented in this article. Based on the physical model of the classical flash method, the present method uses the cutoff time moment of laser heating as zero point. This article investigated the case of constant heat flux heating by using the theoretical method and obtained a new calculation formula. The formula was tested in the case where half temperature rise time is less than the pulse time (i.e., τ0/t0.5 > 1), and the result was satisfactory...
August 2016: Review of Scientific Instruments
F Brandi, F Giammanco, F Conti, F Sylla, G Lambert, L A Gizzi
The use of a gas cell as a target for laser wakefield acceleration (LWFA) offers the possibility to obtain stable and manageable laser-plasma interaction process, a mandatory condition for practical applications of this emerging technique, especially in multi-stage accelerators. In order to obtain full control of the gas particle number density in the interaction region, thus allowing for a long term stable and manageable LWFA, real-time monitoring is necessary. In fact, the ideal gas law cannot be used to estimate the particle density inside the flow cell based on the preset backing pressure and the room temperature because the gas flow depends on several factors like tubing, regulators, and valves in the gas supply system, as well as vacuum chamber volume and vacuum pump speed/throughput...
August 2016: Review of Scientific Instruments
James P Tonks, Ewan C Galloway, Martin O King, Gwilherm Kerherve, John F Watts
A dual purpose mass spectrometer chamber capable of performing molecular beam scattering (MBS) and temperature programmed desorption (TPD) is detailed. Two simple features of this design allow it to perform these techniques. First, the diameter of entrance aperture to the mass spectrometer can be varied to maximize signal for TPD or to maximize angular resolution for MBS. Second, the mass spectrometer chamber can be radially translated so that it can be positioned close to the sample to maximize signal or far from the sample to maximize angular resolution...
August 2016: Review of Scientific Instruments
Liping Yan, Benyong Chen, Shihua Zhang, Pengpeng Liu, Enzheng Zhang
A laser wavelength precision measurement method is presented based on the laser synthetic wavelength interferometer (LSWI). According to the linear relation between the displacements of measurement and reference arms in the interferometer, the synthetic wavelength produced by an unknown wavelength and a reference wavelength can be measured by detecting the phase coincidences of two interference signals. The advantage of the method is that a larger synthetic wavelength resulting from an unknown wavelength very close to the reference wavelength can be easily determined according to the linear relation in the interferometer...
August 2016: Review of Scientific Instruments
N Tsapatsaris, R E Lechner, M Markó, H N Bordallo
In this work, we present the conceptual design of the backscattering time-of-flight spectrometer MIRACLES approved for construction at the long-pulse European Spallation Source (ESS). MIRACLES's unparalleled combination of variable resolution, high flux, extended energy, and momentum transfer (0.2-6 Å(-1)) ranges will open new avenues for neutron backscattering spectroscopy. Its remarkable flexibility can be attributed to 3 key elements: the long-pulse time structure and low repetition rate of the ESS neutron source, the chopper cascade that tailors the moderator pulse in the primary part of the spectrometer, and the bent Si(111) analyzer crystals arranged in a near-backscattering geometry in the secondary part of the spectrometer...
August 2016: Review of Scientific Instruments
Zhan-Wen Ma, Xiao-Dong Su, Xiao-Long Lu, Zhen Wei, Jun-Run Wang, Zhi-Wu Huang, Tian-You Miao, Tong-Ling Su, Ze-En Yao
A compact power supply system for a compact neutron generator has been developed. A 4-stage symmetrical Cockcroft-Walton circuit is adopted to produce 250 kV direct current high-voltage. A 2-stage 280 kV isolation transformer system is used to drive the ion source power supply. For a compact structure, safety, and reliability during the operation, the Cockcroft-Walton circuit and the isolation transformer system are enclosed in an epoxy vessel containing the transformer oil whose size is about ∅350 mm × 766 mm...
August 2016: Review of Scientific Instruments
J A Moya
A method and its system to study the structural evolution on soft magnetic amorphous and nanocrystalline ribbon shaped alloys are presented. With only one sample, a complete set of magnetic and electric data at room and at high temperature are obtained in a relatively short period of time, allowing us to elucidate the structural changes occurring in the alloy and to determine the optimal soft magnetic properties annealing conditions.
August 2016: Review of Scientific Instruments
Shaokai Wang, Jiwen Cui, Jiubin Tan, Yongmeng Liu
In order to further improve the linear datum based geometric measurement accuracy and expand the measurement range, a 6-DoF motion system is developed for realizing a linear datum in the form of motion trajectory of the contact point (CP) of an absolute displacement measurement probe. This linear datum is established based on the concept of coordinate measurement and it does not contain straightness error in theory. The 6-DoF motion system consists of a 6-DoF fine stage and a 1-DoF coarse stage. The probe is moved by the 6-DoF fine stage which is magnetically noncontact supported and parallelly noncontact actuated...
August 2016: Review of Scientific Instruments
S Janardhanraj, G Jagadeesh
A novel concept to generate miniature shockwaves in a safe, repeatable, and controllable manner in laboratory confinements using an in situ oxyhydrogen generator has been proposed and demonstrated. This method proves to be more advantageous than existing methods because there is flexibility to vary strength of the shockwave, there is no need for storage of high pressure gases, and there is minimal waste disposal. The required amount of oxyhydrogen mixture is generated using alkaline electrolysis that produces hydrogen and oxygen gases in stoichiometric quantity...
August 2016: Review of Scientific Instruments
J F Silva, A C Dias, P Araújo, C M A Brett, A Mendes
A new electrochemical cell design suitable for the electrochemical impedance spectroscopy (EIS) studies of chlorine evolution on Dimensionally Stable Anodes (DSA(®)) has been developed. Despite being considered a powerful tool, EIS has rarely been used to study the kinetics of chlorine evolution at DSA anodes. Cell designs in the open literature are unsuitable for the EIS analysis at high DSA anode current densities for chlorine evolution because they allow gas accumulation at the electrode surface. Using the new cell, the impedance spectra of the DSA anode during chlorine evolution at high sodium chloride concentration (5 mol dm(-3) NaCl) and high current densities (up to 140 mA cm(-2)) were recorded...
August 2016: Review of Scientific Instruments
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"