Influence of the column hold-up time measurement accuracy on the prediction of chromatographic band profiles

2004 ◽  
Vol 1050 (2) ◽  
pp. 129-135 ◽  
Author(s):  
P SAJONZ
2013 ◽  
Vol 816-817 ◽  
pp. 1063-1068
Author(s):  
Rou Gang Zhou ◽  
Yun Fei Zhou ◽  
Guang Dou Liu ◽  
Xiao Tu

Currently the time to digital converter (TDC) integrated in FPGA performs time-to-digital conversion in the carry chain mode and inter-slot offset is caused to be severe by internal wiring in the FPGA. Based on the carry chain interpolation method, this paper proposes the method for using a delay module in FPGA to achieve accurate signal delay. By calculating the phase difference of multi-clock signal between two latch sampling points, the interval between two sampling points was obtained. Experimental results indicate a measurement accuracy of 78ps or 52ps can be reached by precisely collecting time through the delay module in FPGA. Compared to the carry chain interpolation method, this method is significantly advantageous in small inter-slot offset, stable performance and convenient design and can meet the requirement for time measurement or requirement by laser interferometer with a nm-level accuracy in nuclear physics.


2012 ◽  
Vol 214 ◽  
pp. 232-236
Author(s):  
Xiao Qiong Zuo ◽  
Ya Xian Liu

Numerous applications require very precise time measurement. Usually, the measurement accuracy is increased by improve the MCU MIPS. It will take the high cost and current consumption, and the accuracy is limited in the MCU MIPS. Using CTMU channels work in conjunction with Analog to Digital converters, the high precise time measurement with low cost MCU can be achieved, and make the time measurement resolution to 1 nanosecond. CTMU module is available in many Microchip microcontrollers.


2012 ◽  
Vol 605-607 ◽  
pp. 1080-1084
Author(s):  
Yu Bo Guo ◽  
Hui Ping Ma ◽  
Qi Xia ◽  
Gang Chen ◽  
Feng Yuan

A real-time measurement method based on multi-vision system is presented for measuring the motion parameters of three-DOF spacecraft simulator. Four cameras are arranged around the motion space of the simulator. When the simulator makes large range translation and rotation motion, 3D coordinate measurement can be realized for any marker provided that such marker is identified by 2 or more cameras. And the motion parameters of simulator can be measured when more than 3 markers are identified in each measurement. The experiment results verify this method and show it can achieve high measurement accuracy.


2021 ◽  
Vol 2094 (3) ◽  
pp. 032043
Author(s):  
M P Sinev ◽  
M A Mitrokhin ◽  
A I Martyshkin ◽  
I N Doroshenko ◽  
A V Dubravin ◽  
...  

Abstract The paper reported the temporal feature analysis method describing for automata models of computation systems. The method is based on from source algorithm to modified algorithm expanding makes it possible to take characteristics of work process related to execution time measurement. The paper considers the transition method from source algorithm representation to modification a final state machine with additional states providing registration of temporal features. The paper demonstrates method usage example on computer system authorization algorithm, approves an algorithm complexity for features registration O(n) for n-states automata algorithm. The method can be used for a large class algorithm, but is recommended to apply it to an algorithm, separated on procedure thus mean of commands amount should be more than 500 for more time measurement accuracy.


Methodology ◽  
2007 ◽  
Vol 3 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Juan Ramon Barrada ◽  
Julio Olea ◽  
Vicente Ponsoda

Abstract. The Sympson-Hetter (1985) method provides a means of controlling maximum exposure rate of items in Computerized Adaptive Testing. Through a series of simulations, control parameters are set that mark the probability of administration of an item on being selected. This method presents two main problems: it requires a long computation time for calculating the parameters and the maximum exposure rate is slightly above the fixed limit. Van der Linden (2003) presented two alternatives which appear to solve both of the problems. The impact of these methods in the measurement accuracy has not been tested yet. We show how these methods over-restrict the exposure of some highly discriminating items and, thus, the accuracy is decreased. It also shown that, when the desired maximum exposure rate is near the minimum possible value, these methods offer an empirical maximum exposure rate clearly above the goal. A new method, based on the initial estimation of the probability of administration and the probability of selection of the items with the restricted method ( Revuelta & Ponsoda, 1998 ), is presented in this paper. It can be used with the Sympson-Hetter method and with the two van der Linden's methods. This option, when used with Sympson-Hetter, speeds the convergence of the control parameters without decreasing the accuracy.


2020 ◽  
pp. 30-35
Author(s):  
Gurami N. Akhobadze

In the age of digital transformation of production processes in industry and science the development and design of intelligent flow sensors for granular and liquid substances transferring through pipelines becomes more important. With this in view new approaches for improving the accuracy of microwave flowmeters are proposed. Taking into account the characteristics ofelectromagnetic waves propagating through a pipeline, a wave scattered by inhomogeneities of the controlled medium is analyzed. Features of the transformation of the polarized scattered wave limiting the geometric dimensions of the pipeline and optimizing the values of the useful scattered signal are revealed. Expediency of collection of the information signal with orthogonal polarization of the scattered wave and through a directional coupler is substantiated. The method of estimating the measurement accuracy with reference to the signal-to-noise ratio at the input of the processing device is given. The research results can be used in cryogenic machine engineering to measure volume and mass flows of liquid cryogenic products.


Sign in / Sign up

Export Citation Format

Share Document