Fine-tuning of LA-ICP-QMS conditions for elemental mapping

2020 ◽  
Vol 35 (11) ◽  
pp. 2494-2497 ◽  
Author(s):  
Johannes T. van Elteren ◽  
Dino Metarapi ◽  
Martin Šala ◽  
Vid S. Šelih ◽  
Ciprian C. Stremtan

For high-speed elemental mapping, LA-ICP-QMS conditions such as scanning speed, repetition rate and acquisition time are optimized as a function of the dosage and the washout time.

2018 ◽  
Vol 24 (3) ◽  
pp. 264-276 ◽  
Author(s):  
Jian Zhuang ◽  
Zhiwu Wang ◽  
Zeqing Li ◽  
Pengbo Liang ◽  
Mugubo Vincent

AbstractTo solve extended acquisition time issues inherent in the conventional hopping-scanning mode of scanning ion-conductance microscopy (SICM), a new transverse-fast scanning mode (TFSM) is proposed. Because the transverse motion in SICM is not the detection direction and therefore presents no collision problem, it has the ability to move at high speed. In TSFM, the SICM probe gradually descends in the vertical/detection direction and rapidly scans in the transverse/nondetection direction. Further, the highest point that decides the hopping height of each scanning line can be quickly obtained. In conventional hopping mode, however, the hopping height is artificially set without a priori knowledge and is typically very large. Consequently, TFSM greatly improves the scanning speed of the SICM imaging system by effectively reducing the hopping height of each pixel. This study verifies the feasibility of this novel scanning method via theoretical analysis and experimental study, and compares the speed and quality of the scanning images obtained in the TFSM with that of the conventional hopping mode. The experimental results indicate that the TFSM method has a faster scanning speed than other SICM scanning methods while maintaining the quality of the images. Therefore, TFSM provides the possibility to quickly obtain high-resolution three-dimensional topographical images of extremely complex samples.


Author(s):  
Kazuyuki Koike ◽  
Hideo Matsuyama

Spin-polarized scanning electron microscopy (spin SEM), where the secondary electron spin polarization is used as the image signal, is a novel technique for magnetic domain observation. Since its first development by Koike and Hayakawa in 1984, several laboratories have extensively studied this technique and have greatly improved its capability for data extraction and its range of applications. This paper reviews the progress over the last few years.Almost all the high expectations initially held for spin SEM have been realized. A spatial resolution of several hundreds angstroms has been attained, which is nearly one order of magnitude higher than that of conventional methods for thick samples. Quantitative analysis of magnetization direction has been performed more easily than with conventional methods. Domain observation of the surface of three-dimensional samples has been confirmed to be possible. One of the drawbacks, a long image acquisition time, has been eased by combining highspeed image-signal processing with high speed scanning, although at the cost of image quality. By using spin SEM, the magnetic structure of a 180 degrees surface Neel wall, magnetic thin films, multilayered films, magnetic discs, etc., have been investigated.


Author(s):  
K. Bobzin ◽  
M. Öte ◽  
M. A. Knoch ◽  
I. Alkhasli ◽  
H. Heinemann

AbstractIn plasma spraying, instabilities and fluctuations of the plasma jet have a significant influence on the particle in-flight temperatures and velocities, thus affecting the coating properties. This work introduces a new method to analyze the stability of plasma jets using high-speed videography. An approach is presented, which digitally examines the images to determine the size of the plasma jet core. By correlating this jet size with the acquisition time, a time-dependent signal of the plasma jet size is generated. In order to evaluate the stability of the plasma jet, this signal is analyzed by calculating its coefficient of variation cv. The method is validated by measuring the known difference in stability between a single-cathode and a cascaded multi-cathode plasma generator. For this purpose, a design of experiment, covering a variety of parameters, is conducted. To identify the cause of the plasma jet fluctuations, the frequency spectra are obtained and subsequently interpreted by means of the fast Fourier transformation. To quantify the significance of the fluctuations on the particle in-flight properties, a new single numerical parameter is introduced. This parameter is based on the fraction of the time-dependent signal of the plasma jet in the relevant frequency range.


2021 ◽  
pp. 002029402110022
Author(s):  
Xiaohua Zhou ◽  
Jianbin Zheng ◽  
Xiaoming Wang ◽  
Wenda Niu ◽  
Tongjian Guo

High-speed scanning is a huge challenge to the motion control of step-scanning gene sequencing stage. The stage should achieve high-precision position stability with minimal settling time for each step. The existing step-scanning scheme usually bases on fixed-step motion control, which has limited means to reduce the time cost of approaching the desired position and keeping high-precision position stability. In this work, we focus on shortening the settling time of stepping motion and propose a novel variable step control method to increase the scanning speed of gene sequencing stage. Specifically, the variable step control stabilizes the stage at any position in a steady-state interval rather than the desired position on each step, so that reduces the settling time. The resulting step-length error is compensated in the next acceleration and deceleration process of stepping to avoid the accumulation of errors. We explicitly described the working process of the step-scanning gene sequencer and designed the PID control structure used in the variable step control for the gene sequencing stage. The simulation was performed to check the performance and stability of the variable step control. Under the conditions of the variable step control where the IMA6000 gene sequencer prototype was evaluated extensively. The experimental results show that the real gene sequencer can step 1.54 mm in 50 ms period, and maintain a high-precision stable state less than 30 nm standard deviation in the following 10 ms period. The proposed method performs well on the gene sequencing stage.


2013 ◽  
Vol 668 ◽  
pp. 283-287
Author(s):  
Sheng Feng Zhou ◽  
Xiao Qin Dai

In order to characterize the dissolution of cast WC particles in Ni-based WC coatings by laser induction hybrid rapid cladding, NiCrBSi+50 wt.% WC coatings are produced on A3 steel by low and high speed laser induction hybrid cladding (LIHC). When laser scanning speed is only 600 mm/min, the crack-free coating has pores and its dilution is as high as 45%. At the bottom of coating, the cast WC particles are dissolved completely and the herringbone M6C eutectics are precipitated. In the center of coating, the cast WC particles are also dissolved completely and the acicular, blocky and dendritic carbides with relatively low hardness are precipitated. At two sides of coating, some cast WC particles are dissolved partially and interact with Ni-based alloy to form an alloyed reaction layer, while others preserve the primary eutectic structure and high hardness. When laser scanning speed and powder feeding rate are increased to 1500 mm/min and 85.6 g/min, the coating has cracks but no pores. Its dilution can be markedly decreased to 7.8%. Moreover, a majority of WC particles are still composed of primary eutectic structure and keep their high hardness, which can play a positive role in strengthening Ni-based metallic matrix.


2008 ◽  
Vol 381-382 ◽  
pp. 35-38
Author(s):  
Yu Guo Cui ◽  
Bing Feng Ju ◽  
J. Aoki ◽  
Yoshikazu Arai ◽  
Wei Gao

In this paper, we applied the contact constant-height mode together with the pre-compensation technique which can realize the capability of high speed as well as faithful topographical image. Before scanning, the slope variation of the micro-structured surface was measured by the capacitance sensor and then stored in a PC. During the surface profile scanning, a piezoelectric actuator is applied which can provide the inconsecutive motion that corresponds to the pre-measured slope variation. As a result, the precision measurement can also be achieved. The validity of the proposed method and its performance are verified by compare the topographical images that were gained by the contact constant-force mode with feedback control. However, the scanning speed of our method is obviously high.


Author(s):  
Patrick O'Donoughue ◽  
Olivier Robin ◽  
Alain Berry

The identification of dynamic loads acting on structures is a key aspect of several engineering domains involving structure-borne sound and vibration problems, stress analysis, or even the study of fatigue-induced structural damages. This work is concerned with the reconstruction of localized transient and distributed random excitations on plates and membranes from their measured vibration response. In previous investigations by the authors, the virtual fields method, an identification approach based on the principle of virtual work, was employed to identify mechanical and acoustic loadings applied to a bending panel. However, vibration data were obtained using scanning laser Doppler vibrometry, which limits the application of the virtual fields method to stationary excitations in both space and frequency. In contrast, the deflectometry technique used here is an optical method that directly provides a full-field measurement of local slopes. With the addition of a high-speed camera, the measurements are resolved in both space and time, enabling the study of nonstationary excitations. Moreover, since the acquisition time is independent of the number of measurement points, high spatial density measurements can be performed in seconds. This paper reviews the principles of the virtual fields method for nonstationary excitations on plates and membranes. The deflectometry technique is then demonstrated and experimental reconstruction results on an aluminum panel are presented for two different load cases: impacting metal marbles (multiple unknown transient excitations) and a diffuse acoustic field excitation. Finally, the identification of acoustic and aerodynamic (turbulent boundary layer) excitations is considered using a membrane as the receiving structure.


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