MINIATURE ORBITRON VACUUM GAUGE WITH BINARY ANODE

2021 ◽  
Vol 77 ◽  
pp. 121-129
Author(s):  
V. A. Korotchenko ◽  
◽  
V. E. Skvortsov ◽  
V. K. Bazylev ◽  
V. V. Praded ◽  
...  
Keyword(s):  
Electron Emission ◽  
Path Length ◽  
Cathode Potential ◽  
Anode Potential ◽  
Electron Current ◽  
Vacuum Gauge ◽  
Electron Trajectories ◽  
Work Volume ◽  
Burning Voltage ◽  
Better Than

Miniature (volume~ 6 cm3) ionization vacuum gauge of orbitron type is developed. The anode of orbitron is made as two wolfram wires with 70 μm diameter, located parallel to gauge axis and being at the distance of 0,5 mm from the axis, much smaller than ion collector radii (8 mm). Diameter and length of the collector are 16 mm and 32 mm, accordingly, of the cathode – 70 μm and 9 mm. Potentials of anode and collector are zero, anode potential is 300 V, cathode potential is (5 – 15) V, cathode burning voltage is 1,6 V at the current of 0, 76 A, electron emission current – 5 μA. Binary anode is applied for thermal degasation (gas away) of electrodes. The numerical simulation has shown that electron trajectories have spiral-shuttle form (as at one wire anode). Spiral radius is (1 – 6) mm, step – (4 – 8) mm, rotation and shuttle periods – 6 ns and 30 ns, the number of turns and traveling time – 1500 and 7 μs, path length and energy – 1000 cm and (20 – 200) eV. It was experimentally confirmed that manometer sensitivity is about 1000 Torr– 1, that is 1,5 orders of magnitude more than for PMI-2 ion manometer. The orbitron with binary anode is better than PMI-2 manometer because it has considerably less value of electron current (two orders of magnitude), cathode burning power (5 times) and work volume (3 times).

An Algorithm for a Near Optimal NC Path Generation in Staircase (Lase) Traversal of Convex Polygonal Surfaces

1999 ◽  
Vol 122 (1) ◽  
pp. 182-190 ◽  
Author(s):  
S. V. Kamarthi ◽  
S. T. S. Bukkapatnam ◽  
S. Hsieh
Keyword(s):  
Rapid Prototyping ◽  
Path Length ◽  
Tool Path ◽  
Path Generation ◽  
Convex Polygons ◽  
Sweep Angle ◽  
Pocket Milling ◽  
Different Shapes ◽  
Path Lengths ◽  
Better Than

This paper presents an analytical model of the tool path for staircase traversal of convex polygonal surfaces, and an algorithm—referred to as OPTPATH—developed based on the model to find the sweep angle that gives a near optimal tool path length. The OPTPATH algorithm can be used for staircase traversal with or without (i) overlaps between successive sweep passes, and (ii) rapid traversal along edge passes. This flexibility of OPTPATH renders it applicable not only to conventional operations such as face and pocket milling, but also to other processes such as robotic deburring, rapid prototyping, and robotic spray painting. The effective tool path lengths provided by OPTPATH are compared with those given by the following two algorithms: (i) a common industrial heuristic—referred to as the IH algorithm—and (ii) an algorithm proposed by Prabhu et al. (Prabhu, P. V., Gramopadhye, A. K., and Wang, H. P., 1990, Int. J. Prod. Res., 28, No. 1, pp. 101–130) referred to as PGW algorithm. This comparison is conducted using 100 randomly generated convex polygons of different shapes and a set of seven different tool diameters. It is found that OPTPATH performs better than both the IH as well as PGW algorithms. The superiority of OPTPATH over the two algorithms becomes more pronounced for large tool diameters. [S1087-1357(00)71501-2]

Effect of Current Direction on the Reliability of Different Capped Cu Interconnects

2005 ◽  
Vol 863 ◽  
Author(s):  
C. L. Gan ◽  
C. Y. Lee ◽  
C. K. Cheng ◽  
J. Gambino
Keyword(s):  
Failure Analysis ◽  
Current Flow ◽  
Void Nucleation ◽  
Electrical Current ◽  
Nucleation Site ◽  
Time To Failure ◽  
Current Direction ◽  
Electron Current ◽  
Electrical Current Flow ◽  
Better Than

AbstractThe reliability of Cu M1-V1-M2-V2-M3 interconnects with SiN and CoWP cap layers was investigated. Similar to previously reported results, the reliability of CoWP capped structures is much better than identical SiN capped structures. However, it was also observed that the reliability of CoWP capped interconnects was independent of the direction of electrical current flow. This phenomenon is different from what was observed for SiN capped structures, where M2 lines with electron current flow in the upstream configuration (“via-below”) have about three times larger median-time-to-failure than identical lines in the downstream configuration (“viaabove”). This is because the Cu/SiN interface is the preferential void nucleation site and provides the fastest diffusion pathway in such an architecture. Failure analysis has shown that fatal partially-spanned voids usually had formed directly below the via for “via-above” configuration, and fully-spanned voids occurred in the lines above the vias for “via-below” configuration.On the other hand, failure analysis for CoWP-coated Cu structures showed that partiallyspanned voids below the via do not cause fatal failures in the downstream configuration. This is because the CoWP layer is conducting, and thus able to shunt current around the void. As a result, a large fully-spanning void is required to cause a failure, just like the upstream configuration. Thus the lifetime of an interconnect with a conducting cap layer is independent of whether the current is flowing upstream or downstream.

Electron Emission from Metals Excited with a CW CO2 Laser

1974 ◽  
Vol 52 (6) ◽  
pp. 475-481
Author(s):  
W. W. Duley
Keyword(s):  
Time Dependence ◽  
Electron Emission ◽  
Thermionic Emission ◽  
Exoelectron Emission ◽  
Electron Current ◽  
Surface Sites ◽  
Complex Dependence ◽  
Cw Co2 Laser ◽  
Ion Emission

The time dependence of electron and ion emission from roughened metals on excitation with a CW CO2 laser has been studied. The emission currents are made up of pulses with durations of several ms. A complex dependence of both ion and electron current on time is observed on time scales ranging from ms to days. An interpretation of these effects based on thermionic emission from localized surface sites is given, and the possible role of exoelectron emission is discussed. Some possible applications of these effects are examined.

Application of WFS for Simultaneous Work Function and Secondary Electron Emission Measurement on Ba Covered Tungsten

2005 ◽  
Vol 473-474 ◽  
pp. 293-296
Author(s):  
György Vida ◽  
Ildikó Beck ◽  
V. Katalin Josepovits ◽  
Miklós Győr
Keyword(s):  
Work Function ◽  
Electron Emission ◽  
Secondary Electron ◽  
Secondary Electron Emission ◽  
Secondary Emission ◽  
Operating Conditions ◽  
Emission Measurement ◽  
Pressure Discharge ◽  
Emission Yield ◽  
Burning Voltage

In the present paper the secondary emission and work function of W covered with different thickness Ba layers are compared. The secondary emission and work function were measured by Work Function Spectroscopy (WFS). It is clearly pointed out that the thin Ba coating causes the the enhancement of electron induced secondary electron emission. In high pressure discharge lamps high secondary emission and high thermionic current are required for reliable operating conditions, i.e., for reaching the nominal burning voltage and current etc. The results prove that the Ba spreading on the W surface from an alkali earth tungstate material is advantageous for lowering the work function and, simultaneously, for increasing the secondary emission yield.

Imaging of Metal/Semiconductor Interface by Ballistic-Electron-Emission Microscopy (Beem)

1992 ◽  
Vol 295 ◽  
Author(s):  
E. Y. Lee ◽  
B. R. Turnew ◽  
J. R. Jimenez ◽  
L. J. Schowalter
Keyword(s):  
Free Path ◽  
Spatial Resolution ◽  
Electron Emission ◽  
Path Length ◽  
Free Path Length ◽  
Mean Free Path ◽  
Ballistic Electron Emission Microscopy ◽  
Semiconductor Interface ◽  
Ballistic Electron ◽  
Emission Microscopy

AbstractStudies in ballistic-electron-emission spectroscopy (BEES) have enabled precise energy measurements of Schottky barrier heights with excellent spatial resolution and, more recently, it was shown that even scattering at the metal/semiconductor interface affects the BEES spectrum [1]. Monte Carlo simulations have been done to predict the spatial resolution of ballistic-electron-emission microscopy (BEEM) [2]. In this paper, we will discuss the experimental spatial resolution of BEEM, and we will also give some of our BEES results for Au/Si and for Au/PtSi/Si. Our experimental BEEM studies indicate that, for Au/Si, hot electron transport is diffusive rather than ballistic, because the inelastic mean free path length (∼100 nm) is much larger than the elastic mean free path length (∼10 nm). This is in agreement with existing theories and with the literature on the internal photoemission method of studying the transport. Even in this diffusive regime, the spatial resolution of BEEM is still expected to be very good, being on the order of 10 nm [2]. Our preliminary work on PtSi shows that it has an attenuation length of 4 nm, which differs significantly from that of Au.

Photodetachment microscopy of H– ion in time-dependent electric and magnetic fields

2018 ◽  
Vol 96 (9) ◽  
pp. 961-968
Author(s):  
De-hua Wang
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Electric Field ◽  
Interference Pattern ◽  
Current Distribution ◽  
Time Dependent ◽  
Electron Current ◽  
Detector Plane ◽  
Electron Trajectories ◽  
Electric And Magnetic Fields

We examine the dynamics of electrons photodetached from the H– ion in time-dependent electric and magnetic fields for the first time. The photodetachment microscopy patterns caused by a time-dependent gradient electric field and magnetic field have been analyzed in great detail based on the semiclassical theory. The interplay of the gradient electric field and magnetic field forces causes an intricate shape of the electron wave and multiple electron trajectories generated by a fixed energy point source can arrive at a given point on the microchannel-plate detector. The interference effects between these electron trajectories cause the oscillatory structures of the electron probability density and electron current distribution, and a set of concentric interference fringes are found at the detector. Our calculation results suggest that the photodetachment microscopy interference pattern on the detector can be adjusted by the electron energy, magnetic field strength, and position of the detector plane. Under certain conditions, the interference pattern in the electron current distribution might be seen on the detector plane localized at a macroscopic distance from the photodetachment source, which can be observed in an actual photodetachment microscopy experiment. Therefore, we make predictions that our work should serve as a guide for future photodetachment microscopy experiments in time-dependent electric and magnetic fields.

scholarly journals High-Precision Automated Reconstruction of Neurons with Flood-filling Networks

2017 ◽  
Author(s):  
Michał Januszewski ◽  
Jörgen Kornfeld ◽  
Peter H. Li ◽  
Art Pope ◽  
Tim Blakely ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Path Length ◽  
Error Rates ◽  
Data Set ◽  
Neural Processes ◽  
Order Of Magnitude ◽  
Block Face ◽  
Microscopy Data ◽  
Better Than ◽  
Volume Electron Microscopy

AbstractReconstruction of neural circuits from volume electron microscopy data requires the tracing of complete cells including all their neurites. Automated approaches have been developed to perform the tracing, but without costly human proofreading their error rates are too high to obtain reliable circuit diagrams. We present a method for automated segmentation that, like the majority of previous efforts, employs convolutional neural networks, but contains in addition a recurrent pathway that allows the iterative optimization and extension of the reconstructed shape of individual neural processes. We used this technique, which we call flood-filling networks, to trace neurons in a data set obtained by serial block-face electron microscopy from a male zebra finch brain. Our method achieved a mean error-free neurite path length of 1.1 mm, an order of magnitude better than previously published approaches applied to the same dataset. Only 4 mergers were observed in a neurite test set of 97 mm path length.

Research into the corrosion behavior of carbon steel in simulated reverse osmosis product water and seawater using a wire beam electrode

2015 ◽  
Vol 62 (3) ◽  
pp. 176-181
Author(s):  
Min Zhang ◽  
Hong-Hua Ge ◽  
Xue-Juan Wang ◽  
Xin-Jing Meng ◽  
Yu-Zeng Zhao ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Reverse Osmosis ◽  
Corrosion Behavior ◽  
Corrosion Potential ◽  
Potential Difference ◽  
Cathode Potential ◽  
Anode Potential ◽  
Content Type ◽  
Product Water ◽  
Simulated Seawater

Purpose – The purpose of this study was to explore the differences in the corrosion behavior of carbon steel in simulated reverse osmosis (RO) product water, and in seawater. Design/methodology/approach – The wire beam electrodes (WBE) and coupons made from Type Q235 carbon steel and were immersed in simulated reverse osmosis product water, and in seawater, for fifteen days. The corrosion potential distribution on the WBE at different times was measured. The corrosion rates of the carbon steel in different solutions were obtained using weight loss determinations. The different corrosion behavior of carbon steel in the two kinds of solution was analyzed. Findings – The results showed that the average corrosion potential, micro-cathode potential and micro-anode potential of the WBE decreased with time in simulated RO product water. During this period, the maximum potential difference between micro-cathodes and micro-anodes on the WBE surface also decreased with time. The potential difference was more than 260mV at the beginning of the test and was still greater than 110mV after fifteen days of immersion. The positions of cathodes and anodes remained basically unchanged and corrosion took place on the localized anode during the experiments. The average corrosion potential, micro-cathode potential and micro-anode potential on the WBE surface also decreased with time in the simulated seawater. However, the maximum potential difference between micro-cathode and micro-anode on the WBE surface in the simulated seawater was much smaller than was the case in simulated RO product water. It was 37.8 mV at the beginning of the test and was no more than 12mV after two days immersion. The positions of cathode region and anode kept changing, leading to overall uniform corrosion. The actual corrosion rate on the corroded anode region in simulated RO product water was greater than was the case in simulated seawater. Originality/value – The corrosion behavior differences of carbon steel between in RO product water and in seawater were revealed by using wire beam electrodes (WBE). From the micro point of view, it explained the reason why the actual corrosion rate of carbon steel in RO product water was greater than that in sea water. The results can be helpful to explore future corrosion control methods for carbon steel in RO product water.

scholarly journals Communicability distance reveals hidden patterns of Alzheimer disease

2020 ◽  
Author(s):  
Eufemia Lella ◽  
Ernesto Estrada
Keyword(s):  
Alzheimer Disease ◽  
Path Length ◽  
Brain Regions ◽  
Brain Network ◽  
Efficient System ◽  
Brain Hemispheres ◽  
Disconnection Syndrome ◽  
Path Lengths ◽  
The Brain ◽  
Better Than

AbstractThe communicability distance between pairs of regions in human brain is used as a quantitative proxy for studying Alzheimer disease. Using this distance we obtain the shortest communicability path lengths between different regions of brain networks from Alzheimer diseased (AD) patients and healthy cohorts (HC). We show that the shortest communicability path length is significantly better than the shortest topological path length in distinguishing AD patients from HC. Based on this approach we identify 399 pairs of brain regions for which there are very significant changes in the shortest communicability path length after AD appears. We find that 42% of these regions interconnect both brain hemispheres, 28% connect regions inside the left hemisphere only and 20% affects vermis connection with brain hemispheres. These findings clearly agree with the disconnection syndrome hypothesis of Alzheimer disease. Finally, we show that in 76.9% damaged brain regions the shortest communicability path length drops in AD in relation to HC. This counterintuitive finding indicates that AD transforms the brain network into a more efficient system from the perspective of the transmission of the disease, because it drops the circulability of the disease factor around the brain regions in relation to its transmissibility to other regions.

The Use of Some Metal Photocathodes for Absolute Intensity Measurements in the Soft X-ray-Vacuum Ultraviolet

1977 ◽  
Vol 31 (4) ◽  
pp. 317-320 ◽  
Author(s):  
Erskine J. T. Burns ◽  
John F. Thurston
Keyword(s):  
Electron Emission ◽  
Vacuum Ultraviolet ◽  
Normal Incidence ◽  
Absolute Intensity ◽  
Surface Smoothness ◽  
Total Electron ◽  
X Ray ◽  
Intensity Measurements ◽  
Better Than

The total electron emission of better than 99.9% bulk purity aluminum, titanium, iron, and copper has been measured for six photon energies impinging at near normal incidence (90 ± 0.8°) to the electron emitting surface. Six nearly monochromatic photon energies between 0.109 and 1.49 keV were used. Surface smoothness, oxygen, and carbon contaminants were found to strongly influence the electron emission from these devices.

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