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Review of Scientific Instruments

Stephan Pröller, Daniel Moseguí González, Chenhuii Zhu, Eric Schaible, Cheng Wang, Peter Müller-Buschbaum, Alexander Hexemer, Eva M Herzig
In order to tailor the assembling of polymers and organic molecules, a deeper understanding of the kinetics involved in thin film production is necessary. While post-production characterization only provides insight on the final film structure, more sophisticated experimental setups are needed to probe the structure formation processes in situ during deposition. The drying kinetics of a deposited organic thin film strongly influences the assembling process on the nanometer scale. This work presents an experimental setup that enables fine control of the atmosphere composition surrounding the sample during slot die coating, while simultaneously probing the film formation kinetics using in situ grazing incidence X-ray scattering and spectroscopy...
June 2017: Review of Scientific Instruments
Lee Li, Jiaming Xiong, Yong Cheng, Mingyang Peng, Yuan Pan
The capillary discharge triggered by a pulse source can produce a certain length of plasma jet. In this paper, the physical process of the capillary discharge jet is analyzed, and it is pointed out that the capillary plasma-jet length is significantly affected by the expansion pressure caused by the arc discharge in the capillary chamber. The greater the pressure in the capillary chamber is, the longer the jet length. The experimental setup of the capillary discharge is established in atmospheric pressure air...
June 2017: Review of Scientific Instruments
Zhongwei Li, Pengwei Zhang, Lixin Zang, Feng Qin, Zhiguo Zhang, Hongli Zhang
Using diphenylisobenzofuran (C20H14O) as a singlet oxygen ((1)O2) reporter, a comparison method, which can be used to measure the singlet oxygen quantum yield (ΦΔ) of the photosensitizer quantitatively, is presented in this paper. Based on this method, an automatic measuring instrument of singlet oxygen quantum yield is developed. The singlet oxygen quantum yield of the photosensitizer hermimether and aloe-emodin is measured. It is found that the measuring results are identical to the existing ones, which verifies the validity of the measuring instrument...
June 2017: Review of Scientific Instruments
Mrinalini Mishra, Chi-Chung Kei, Yu-Hsuan Yu, Wei-Szu Liu, Tsong-Pyng Perng
Uniform tantalum oxide thin films, with a growth rate of 0.6 Å/cycle, were fabricated on vertically aligned, 10 cm-long, silicon substrates using an innovative atomic layer deposition (ALD) design. The ALD system, with a reaction chamber depth of 13.3 cm and 18 vertical enclosed channels (inner diameter 1.3 cm), was coupled with a shower-head type precursor conduit plate bearing 6 radial channels. This design enabled deposition on 6 silicon substrates at a time. The degrees of non-uniformity of deposits along the length of the silicon wafer and across different positions in the ALD chamber were found to be 1...
June 2017: Review of Scientific Instruments
Ruisong Ma, Qing Huan, Liangmei Wu, Jiahao Yan, Qiang Zou, Aiwei Wang, Christian A Bobisch, Lihong Bao, Hong-Jun Gao
Upgrade of a commercial ultra-high vacuum four-probe scanning tunneling microscopy system for atomic resolution capability and thermal stability is reported. To improve the mechanical and thermal performance of the system, we introduced extra vibration isolation, magnetic damping, and double thermal shielding, and we redesigned the scanning structure and thermal links. The success of the upgrade is characterized by its atomically resolved imaging, steady cooling down cycles with high efficiency, and standard transport measurement capability...
June 2017: Review of Scientific Instruments
S Chauhan, T Barman, M Bhatnagar, M Ranjan, S Mukherjee
A large plasma fireball is formed using a reverse biased planar sputter magnetron source. The magnetic field considerably reduces the contact area of the anode with the plasma and results in the formation of the fireball. Ions are extracted from the fireball using a large voltage cathode sheath of the grounded sample holder. The physical mechanism for the extraction of the ions from the fireball along with the effect of the sample holder on the fireball and the discharge current is discussed. The device is shown as a novel tool for developing nanodot patterns on a GaSb substrate without the use of additional ion source or power supplies...
June 2017: Review of Scientific Instruments
H Sawada, T Daykin, H S McLean, H Chen, P K Patel, Y Ping, F Pérez
Simultaneous monochromatic crystal imaging at 4.5 and 8.0 keV with x-rays produced by a single short-pulse laser is presented. A layered target consisting of thin foils of titanium and copper glued together is irradiated by the 50 TW Leopard short-pulse laser housed at the Nevada Terawatt Facility. Laser-accelerated MeV fast electrons transmitting through the target induce Kα fluorescence from both foils. Two energy-selective curved crystals in the imaging diagnostic form separate monochromatic images on a single imaging detector...
June 2017: Review of Scientific Instruments
Masashi Kiguchi, Tsukasa Funane, Hiroki Sato
A new measurand is proposed for use in continuous wave near-infrared spectroscopy (cw-NIRS). The conventional measurand of cw-NIRS is l△c, which is the product of the change in the hemoglobin concentration (△c) and the partial path lengh (l), which depends on the source-detector (SD) distance (d). The SD distance must remain constant during cw-NIRS measurements, and we cannot compare the l△c value with that obtained using a different SD distance. In addition, the conventional measurand obtained using the standard measurement style sometimes includes a contribution from the human scalp...
June 2017: Review of Scientific Instruments
Jun-Bao Li, Xiaodan Xie, Jia Zhai, Jeng-Shyang Pan
Hyperspectral remote sensing has a strong ability of object information expression, so it provides better support for object classification. Many methods are proposed for the hyperspectral data classification. The spectrum classification is a classical nonlinear problem, and a kernel-based machine is feasible to classify the spectrum data. In the nonlinear kernel-based space, the spectrum data are more discriminative. The kernel functions determine the data distribution in the feature space. In this paper, we propose the quasiconformal multiple kernels-based machine learning for the hyperspectral data classification...
June 2017: Review of Scientific Instruments
A N Oliveira, L S Moreira, R L Sacramento, L Kosulic, V B Brasil, W Wolff, C L Cesar
We present the development of a mount that accommodates a mirror and a piezoelectric actuator with emphasis on physical needs for low temperature operation. The design uses a monolithic construction with flexure features that allow it to steadily hold the mirror and the piezoelectric actuator without glue and accommodate differential thermal contraction. The mount is small and lightweight, adding little heat capacity and inertia. It provides a pre-loading of the piezoelectric actuator as well as a good thermal connection to the mirror and a thermal short across the piezoelectric actuator...
June 2017: Review of Scientific Instruments
Letian Guo, Jiawei Li, Wenhua Huang, Hao Shao, Tao Ba, Shaoyi Xie
A novel compact five-port waveguide power divider based on the single-ridge waveguide and three-ridge waveguide structure is proposed. It is realized by the coupling of the TE10 and TE30 modes. At the central coupling section, the single-ridge and three-ridge waveguides are used to constitute the conventional rectangular waveguide to reduce the sectional sizes. It consists of one input port, two output ports, and two isolated ports. For validation, a compact five-port power divider is designed, fabricated, and measured...
June 2017: Review of Scientific Instruments
Zdeněk Janů, František Soukup
We show a continuous reading superconducting quantum interference detector magnetometer used to measure the magnetic moment of small samples of materials as a function of an applied magnetic field, temperature, and time. A sample is held stationary while the magnetic field and sample temperature may be varied continuously in an arbitrary way, determined by the user. The applied field range is ±25 mT and the temperature range is 4.2-150 K. The advantage of a stationary sample technique is that the sample is not exposed to variations in the magnetic field or temperature, which may set in when the sample is moving...
June 2017: Review of Scientific Instruments
Ondrej Grover, Jiri Adamek, Jakub Seidl, Alexis Devitre, Miroslav Sos, Petr Vondracek, Petra Bilkova, Martin Hron
A new multi-pin probe head was installed and tested at the COMPASS tokamak. The probe head consists of several ball-pen and Langmuir probes in similar geometric configurations, which enables fast, simultaneous measurements of the radial and poloidal electric field components from differences of plasma or floating potentials using appropriately positioned ball-pen or Langmuir probes, respectively. The fast measurements of the radial electric field are compared with other methods of measuring selected frequency components of the radial electric field...
June 2017: Review of Scientific Instruments
R Gangradey, J Mishra, S Mukherjee, P Panchal, P Nayak, J Agarwal, Y C Saxena
Using a Gifford-McMahon cycle cryocooler based refrigeration system, a single barrel hydrogen pellet injection (SPINS-IND) system is indigenously developed at Institute for Plasma Research, India. The injector is based on a pipe gun concept, where a pellet formed in situ in the gun barrel is accelerated to high speed using high pressure light propellant gas. The pellet size is decided by considering the Greenwald density limit and its speed is decided by considering a neutral gas shielding model based scaling law...
June 2017: Review of Scientific Instruments
Huaduo Shi, Weiliang Shi, Ran Zhang, Junyi Zhai, Jinkui Chu, Shuxiang Dong
Micro/nanomaterials and devices have attracted great interest in recent years because of their extensive application prospects in almost all kinds of fields. However, the manipulations of the material at the micro/nanoscale, such as the separation or transfer of a micro/nano-object in the process of assembling micro/nanodevices, are quite difficult. In this paper, we present a micromachined micro-gripper made of photoresist material (SU-8) and driven by piezoelectric Pb(Mg,Nb)O3-PbTiO3 single crystal pieces...
June 2017: Review of Scientific Instruments
A Persaud, Q Ji, E Feinberg, P A Seidl, W L Waldron, T Schenkel, A Lal, K B Vinayakumar, S Ardanuc, D A Hammer
A new approach for a compact radio-frequency (RF) accelerator structure is presented. The new accelerator architecture is based on the Multiple Electrostatic Quadrupole Array Linear Accelerator (MEQALAC) structure that was first developed in the 1980s. The MEQALAC utilized RF resonators producing the accelerating fields and providing for higher beam currents through parallel beamlets focused using arrays of electrostatic quadrupoles (ESQs). While the early work obtained ESQs with lateral dimensions on the order of a few centimeters, using a printed circuit board (PCB), we reduce the characteristic dimension to the millimeter regime, while massively scaling up the potential number of parallel beamlets...
June 2017: Review of Scientific Instruments
B Uder, U Hartmann
Two-dimensional atomically flat sheets with a high flexibility are very attractive as ultrathin membranes but are also inherently challenging for microscopic investigations. We report on a method using Scanning Tunneling Microscopy (STM) under ultra-high vacuum conditions for large-scale mapping of several-micrometer-sized freestanding single and multilayer graphene membranes. This is achieved by operating the STM at unusual parameters. We found that large-scale scanning on atomically thin membranes delivers valuable results using very high tip-scan speeds combined with high feedback-loop gain and low tunneling currents...
June 2017: Review of Scientific Instruments
Giacomo Ciani, Andrew Chilton, Stephen Apple, Taiwo Olatunde, Michael Aitken, Guido Mueller, John W Conklin
We report on the design and sensitivity of a new torsion pendulum for measuring the performance of ultra-precise inertial sensors and for the development of associated technologies for space-based gravitational wave observatories and geodesy missions. The apparatus comprises a 1 m-long, 50 μm-diameter tungsten fiber that supports an inertial member inside a vacuum system. The inertial member is an aluminum crossbar with four hollow cubic test masses at each end. This structure converts the rotation of the torsion pendulum into translation of the test masses...
June 2017: Review of Scientific Instruments
J Mimila-Arroyo
In this paper, it is demonstrated that the free electron gas primary thermometer based on a bipolar junction transistor is able to provide the temperature with an accuracy of a few parts per million. Its simple functioning principle exploits the behavior of the collector current when properly biased to extract the temperature. Using general purpose silicon transistors at the water triple point (273.16 K) and gallium melting point (302.9146), an accuracy of a few parts per million has been reached, constituting the simplest and the easiest to operate primary thermometer, that might be considered even for the redefinition of Kelvin...
June 2017: Review of Scientific Instruments
L A Gomes Perini, P Bleuet, J Filevich, W Parker, B Buijsse, L F Tz Kwakman
Recent improvements in a SEM-based X-ray tomography system are described. In this type of equipment, X-rays are generated through the interaction between a highly focused electron-beam and a geometrically confined anode target. Unwanted long-term drifts of the e-beam can lead to loss of X-ray flux or decrease of spatial resolution in images. To circumvent this issue, a closed-loop control using FFT-based image correlation is integrated to the acquisition routine, in order to provide an in-line drift correction...
June 2017: Review of Scientific Instruments
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