scholarly journals Metrology of a Focusing Capillary Using Optical Ptychography

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6462
Author(s):  
Xiaojing Huang ◽  
Evgeny Nazaretski ◽  
Weihe Xu ◽  
Dean Hidas ◽  
Mark Cordier ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Laser Beam ◽  
Gaussian Distribution ◽  
Capillary Surface ◽  
Functional Surfaces ◽  
Phase Profile ◽  
Reflective Optics ◽  
Focusing Property ◽  
Focused Beam ◽  
Quantitative Tool

The focusing property of an ellipsoidal monocapillary has been characterized using the ptychography method with a 405 nm laser beam. The recovered wavefront gives a 12.5×10.4μm2 focus. The reconstructed phase profile of the focused beam can be used to estimate the height error of the capillary surface. The obtained height error shows a Gaussian distribution with a standard deviation of 1.3 μm. This approach can be used as a quantitative tool for evaluating the inner functional surfaces of reflective optics, complementary to conventional metrology methods.

A model for the effect of bias for cholesterol on the population at risk.

1988 ◽  
Vol 34 (11) ◽  
pp. 2256-2259 ◽  
Author(s):  
M H Kroll ◽  
M Ruddel ◽  
R J Elin
Keyword(s):  
At Risk ◽  
Standard Deviation ◽  
Reference Values ◽  
Gaussian Distribution ◽  
Population Distribution ◽  
Reference Value ◽  
Mean Value ◽  
The Body ◽  
Methodological Bias ◽  
The Mean

Abstract The location of the Reference Value for an analyte within the population distribution affects the magnitude of error due to methodological bias. Using the gaussian distribution, we evaluated the effects of systematic and proportional biases of the method (positive and negative), mean value, and standard deviation on the magnitude of error. We chose four Reference Values for cholesterol as a model. For a population with a mean of 2.0 and SD of 0.36 g of cholesterol per liter, a 3% positive proportional bias causes sixfold more error at the 50th percentile than at the 97.5th. In general, the error for a given bias (proportional or systematic) is greater for a Reference Value within the body than at the tails of the distribution. Further, the magnitude of the error varies as a function of the mean and standard deviation of the population.

scholarly journals Over-volted breakdown and recovery of short nitrogen spark gaps

2010 ◽  
Vol 28 (3) ◽  
pp. 443-450 ◽  
Author(s):  
Xinjing Cai ◽  
Xiaobin Zou ◽  
Xinxin Wang ◽  
Liming Wang ◽  
Zhicheng Guan ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Breakdown Voltage ◽  
Gaussian Distribution ◽  
Recovery Time ◽  
Time Dependent ◽  
Experimental Conditions ◽  
Pulse Technique ◽  
Residual Nitrogen ◽  
Spark Gap ◽  
Gap Spacing

AbstractThe characteristic of the over-volted breakdown and the gaseous recovery in short nitrogen gaps was experimentally studied. It was found that the breakdown voltage of the gap changes from shot to shot even with the same experimental conditions and obeys Gaussian distribution. The over-volted factor is reduced with an increasing pressure. With a 2.7-mm gap the over-volted factors are 4.53 for 0.1 MPa pressure and 1.74 for 0.4 MPa. The over-volted breakdown voltage depends individually on the gap spacing d and the gas pressure p, rather than on the product of pd. An empirical formula of the breakdown voltage as a function of p and d was derived. The time-dependent recovery of the breakdown voltage, RVb, was obtained using a two-pulse technique. The second breakdown voltage also obeys Gaussian distribution, but it is normally with a smaller standard deviation especially when the interpulse spacing of Δt is relatively short. As a whole, RVb rises with the increase of Δt. However, an intermediate plateau is always observed and it starts when the second breakdown voltage is a little bit higher than the static breakdown voltage of the gap. The first rising edge of the RVb curve corresponds to the recovery of the electro-neutrality and the density. The intermediate plateau and the following rising edge take the spark gap much longer time to recover. The processes governing these two latter phases are as yet not fully clear. It is attributed to the delayed recombination of the residual nitrogen atoms on the cathode to produce the initial electrons for the second breakdown. An increase in pressure has resulted in an upward shift of the intermediate plateau and a shortening in the recovery time of the gaps. The second spark generally does not follow the path of the first spark.

The Effect of Blunders on Collision Risk Calculations

1958 ◽  
Vol 11 (1) ◽  
pp. 29-33 ◽  
Author(s):  
J. B. Parker
Keyword(s):  
Standard Deviation ◽  
Gaussian Distribution ◽  
Collision Risk

One method of controlling aircraft is to assign each a given track, the distance between successive tracks being sufficiently great to ensure that the collision risk is very low. Most approaches to the problem of stipulating what this spacing should be, assume that the possible divergences of an aircraft about its preassigned path follow a Gaussian distribution with a standard deviation obtained by considering all the usual sources of navigational error (e.g. compass error and fixing error) together with meteorological errors due to inaccuracies in forecasting.

Fluorescence imaging by confocal microspectrometry

1992 ◽  
Vol 50 (2) ◽  
pp. 1520-1521
Author(s):  
E. Da Silva ◽  
B. Lenain ◽  
M. Manfait
Keyword(s):  
Laser Beam ◽  
Fluorescence Imaging ◽  
Gaussian Distribution ◽  
Spectral Distribution ◽  
Depth Of Focus ◽  
Spectral Image ◽  
Scanning Method ◽  
Optical Scanner ◽  
System A ◽  
Spread Factor

Confocal microfluorometry possesses many advantages. In particular, it provides the possibility to control the size of the analyzed surface and the depth of focus.The laser focussed on a line under microscope has been achieved either with cylindrical optics or by spot deflection (to conserve the Gaussian distribution of the laser beam).Associated with a 2D detector, this focussed line gives the spectral distribution for all the points of the line. A motorized stage in the direction perpendicular to the line gives all the data to rebuild a spectral image.We present a new scanning method rigorously confocal and giving, in addition, the possibility to change continuously the spread factor (defined by the number of pixels of the detector divided by the dimension of the line onto the sample under microscope), from few pixels by micrometer up to 20 pixels by micrometer.Figure 1 shows the principle of the system; a first optical scanner scans a line onto the sample under microscope.

Producing Three-Dimensional Shapes by Laser Milling

1990 ◽  
Vol 112 (4) ◽  
pp. 375-379 ◽  
Author(s):  
R. K. C. Hsu ◽  
S. M. Copley
Keyword(s):  
Carbon Dioxide ◽  
Laser Beam ◽  
Carbon Dioxide Laser ◽  
Three Dimensional ◽  
Milling Process ◽  
Model Material ◽  
Layer Plane ◽  
Uniform Thickness ◽  
Laser Milling ◽  
Focused Beam

A laser milling process employing a pulsed, carbon dioxide laser has been investigated using graphite as a model material. Material is removed by scanning the focused beam across the surface of the workpiece leaving behind a series of narrow, parallel, overlapping grooves. These grooves, together, constitute the removal of a thin layer of uniform thickness lying parallel to a layer plane. In order to remove layers bounded at the edge by upright walls perpendicular to the layer plane, the laser beam must be tilted with respect to the layer plane. Using this approach, it is possible to produce perpendicular steps and cylindrical surfaces.

Submicrometer-Linewidth Laser Doping

1982 ◽  
Vol 17 ◽  
Author(s):  
J. Y. Tsao ◽  
D. J. Ehrlich
Keyword(s):  
Laser Beam ◽  
Surface Relief ◽  
Nonlinear Dependence ◽  
Thermal Gradients ◽  
Localized Heating ◽  
Negative Surface ◽  
Diffusion Rates ◽  
Dopant Atoms ◽  
Focused Beam ◽  
Tile Surface

ABSTRACTDopant patterns of 250-nm linewidth have been written in silicon by localized heating with a cw laser beam, and then transferred into positive and negative surface-relief patterns by preferential etching. The tightly focused beam both generates free dopant atoms and simultaneously promotes solidstate diffusion into the substrate. Because of the nonlinear dependence of diffusion rates on temperature, the linewidths of the patterns are substantially narrower than those of both the temperature and the laser-beam profiles on tile surface. In addition, an enhancement is observed in diffusion rates under the strong thermal gradients associated with highly localized heating.

Sign in / Sign up

Export Citation Format

Share Document