Der Übergang der Elektronenlawine in den Kanalaufbau bei hoher Überspannung in Stickstoff (mit geringem CH4-Zusatz)

1963 ◽  
Vol 18 (5) ◽  
pp. 587-590 ◽  
Author(s):  
H. Tholl
Keyword(s):  
Light Intensity ◽  
Space Charge ◽  
The State ◽  
Electron Avalanche

The transition of an electron avalanche into streamers directed both to the anode and to the cathode was observed in nitrogen (low amounts of methan added). The light intensity emitted by the streamers was photographed by means of a camera and simultaneously registered by photomultiplier technique. By comparison of photographs and oscillograms the streamer velocities could be determined to be vAK=1·108 cm/sec and vKK=3,1·108 cm/sec for the anode-directed streamer and the cathode-directed streamer respectively. Further it was found that the development of the anode directed streamer already begins in the state of reduced carrier amplification owing to the space charge of the avalanche itself.

scholarly journals Adaptive-illumination STED nanoscopy

2017 ◽  
Vol 114 (37) ◽  
pp. 9797-9802 ◽  
Author(s):  
Jörn Heine ◽  
Matthias Reuss ◽  
Benjamin Harke ◽  
Elisa D’Este ◽  
Steffen J. Sahl ◽  
...  
Keyword(s):  
Light Intensity ◽  
Biological Imaging ◽  
The State ◽  
Lower Intensity ◽  
2D And 3D ◽  
Imaging Conditions ◽  
State Difference

The concepts called STED/RESOLFT superresolve features by a light-driven transfer of closely packed molecules between two different states, typically a nonfluorescent “off” state and a fluorescent “on” state at well-defined coordinates on subdiffraction scales. For this, the applied light intensity must be sufficient to guarantee the state difference for molecules spaced at the resolution sought. Relatively high intensities have therefore been applied throughout the imaging to obtain the highest resolutions. At regions where features are far enough apart that molecules could be separated with lower intensity, the excess intensity just adds to photobleaching. Here, we introduce DyMIN (standing for Dynamic Intensity Minimum) scanning, generalizing and expanding on earlier concepts of RESCue and MINFIELD to reduce sample exposure. The principle of DyMIN is that it only uses as much on/off-switching light as needed to image at the desired resolution. Fluorescence can be recorded at those positions where fluorophores are found within a subresolution neighborhood. By tuning the intensity (and thus resolution) during the acquisition of each pixel/voxel, we match the size of this neighborhood to the structures being imaged. DyMIN is shown to lower the dose of STED light on the scanned region up to ∼20-fold under common biological imaging conditions, and >100-fold for sparser 2D and 3D samples. The bleaching reduction can be converted into accordingly brighter images at <30-nm resolution.

scholarly journals Space Charge Fields in the Development of a Townsend Discharge in Nitrogen

1969 ◽  
Vol 22 (4) ◽  
pp. 447 ◽  
Author(s):  
AA Doran
Keyword(s):  
Light Intensity ◽  
Electric Field ◽  
Space Charge ◽  
Applied Electric Field ◽  
Dominant Role ◽  
Light Output ◽  
Exact Relation ◽  
Townsend Discharge ◽  
Discharge Gap ◽  
Infor Mation

As the CUlTent through a spark rises into the milliampere range, ionization due to fields produced by space charge plays an increasingly dominant role. Infor� mation on these fields can be obtained from analysis of the light intensity emitted at different points along the axis of the discharge. In an earlier publication (Doran 1968) photomultiplier records of the light output obtained at various times during the growth of a Townsend discharge in nitrogen (pd = 600 torr cm) were analysed by an approximate method. In the present paper a more exact relation between the light emitted and the variation in local electric field is derived, enabling the previous results to be re.analysed. This has provided a quantitative picture, spatially and temporally resolved, of the development of these fields, which are associated with luminous fronts observed to propagate back and forth across the discharge gap. The magnitude of the field variations is in general about 10-20% of the applied electric field.

Die Raumladungsbremsung von Elektronenlawinen

1959 ◽  
Vol 14 (11) ◽  
pp. 989-994
Author(s):  
K. J. Schmidt-Tiedemann
Keyword(s):  
Electric Field ◽  
Space Charge ◽  
Electron Avalanche ◽  
Homogeneous Electric Field ◽  
First Order ◽  
Charge Field ◽  
The Common ◽  
Negative Space ◽  
Theoretical Results ◽  
First Order Perturbation

The electric field generated by the positive and negative space charge of a single electron avalanche moving in a homogeneous electric field is calculated. Treating the interaction of the avalanche with its own space charge field as a first order perturbation, a growth formula is obtained which differs markedly from the common TOWNSEND formula. The theoretical results fit well with experimental data on avalanche statistics reported in the literature.

Probe of Field Collapse in a-Si:H Solar Cells

1996 ◽  
Vol 420 ◽  
Author(s):  
Qi Wang ◽  
Richard S. Crandall
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Light Intensity ◽  
Space Charge ◽  
Fill Factor ◽  
Illumination Intensity ◽  
Solar Cell Performance ◽  
Intensity Dependence ◽  
Low Levels ◽  
Good Agreement

AbstractWe study the effect of illumination intensity on solar cell performance in a-Si:H solar cells. We find that the fill factor strongly depends on light intensity. As we increase the illumination intensity from low levels to one sun we observe a decrease in fill factor of approximately 15% in as grown cells. We attribute this effect to electric field collapse inside the cell. We propose that photogenerated space charge (free and trapped charge) increases with light intensity and causes field collapse. We describe the origin of space charge and the associated capacitance - photocapacitance. We measure the photocapacitance as a barometer to probe the collapsed field. We obtain a good agreement between photocapacitance experiments and theory. We also explore the light intensity dependence of photocapacitance and explain the decrease of FF with the increasing light intensity.

scholarly journals Foraging behavior of Melipona rufiventris Lepeletier (Apinae; Meliponini) in Ubatuba, SP, Brazil

2007 ◽  
Vol 67 (1) ◽  
pp. 133-140 ◽  
Author(s):  
AO. Fidalgo ◽  
AMP. Kleinert
Keyword(s):  
Relative Humidity ◽  
Light Intensity ◽  
Foraging Behavior ◽  
The State ◽  
Foraging Activity ◽  
Humid Climate ◽  
Positive Correlation ◽  
Pollen Loads ◽  
Brood Comb ◽  
Length Of The Day

This study describes how the foraging activity of Melipona rufiventris is influenced by the environment and/or by the state of a colony. Two colonies were studied in Ubatuba, SP (44° 48’ W and 23° 22’ S) from July/2000 to June/2001. These colonies were classified as strong (Colony 1) and intermediate (Colony 2) according to their general conditions: population and brood comb size and number of food pots. The bees were active from dawn to dusk. The number of pollen loads presented a positive correlation with relative humidity (r s = 0.401; p <0.01) and was highest between 70 and 90%. However, it was negatively correlated with temperature (r s = -0.228; p <0.01) showing a peak between 18 and 23 °C. The number of nectar loads presented a positive correlation with temperature (r s = 0.244; p <0.01) and light intensity (r s = 0.414; p <0.01); it was greater between 50 and 90% of relative humidity and 20 and 30 °C of temperature. They collected more nectar than pollen throughout the day, and were more active between 6 and 9 hours. Workers from Colony 1 (strong) collected nectar in greater amounts and earlier than those from Colony 2 (intermediate). The number of pollen, nectar and resin loads varied considerably between the study days. Peaks of pollen collection occurred earlier in months with longer days and in a hotter and more humid climate. The foraging behavior of M. rufiventris is probably affected by the state of the colony and by environmental conditions, notably temperature, relative humidity, light intensity and length of the day.

scholarly journals Review of the PEA Method for Space Charge Measurements on HVDC Cables and Mini-Cables

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3512 ◽  
Author(s):  
Giuseppe Rizzo ◽  
Pietro Romano ◽  
Antonino Imburgia ◽  
Guido Ala
Keyword(s):  
Space Charge ◽  
High Voltage ◽  
Direct Current ◽  
State Of The Art ◽  
The State ◽  
Cylindrical Geometry ◽  
Full Size ◽  
High Voltage Direct Current ◽  
Charge Measurement ◽  
Current Review

This review takes into account articles and standards published in recent years concerning the application of the Pulsed Electro Acoustic (PEA) method for space charge measurement on High Voltage Direct Current (HVDC) cables and mini-cables. Since the 80s, the PEA method has been implemented for space charge measurements on flat specimens in order to investigate space charge phenomena and to evaluate the ageing of dielectrics. In recent years, this technique has been adapted to cylindrical geometry. Several studies and experiments have been carried out on the use of the PEA method for full size cables and HVDC cable models. The experiments have been conducted using different arrangements of the measurement setup and focusing attention on different aspects of space charge phenomena. In this work, the importance of space charge measurement is highlighted and the state-of-the-art PEA method application to full size cables and mini-cables is described. The main aim of this paper is to offer a complete and current review of this technique. In addition, limits on the use of PEA method are examined and main possible directions of research are proposed in order to improve the applicability, reliability, and replicability of this method.

scholarly journals Design of a Novel Remote Monitoring System for Smart Greenhouses Using the Internet of Things and Deep Convolutional Neural Networks

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5045
Author(s):  
Adel Mellit ◽  
Mohamed Benghanem ◽  
Omar Herrak ◽  
Abdelaziz Messalaoui
Keyword(s):  
Internet Of Things ◽  
Light Intensity ◽  
Remote Monitoring ◽  
Low Cost ◽  
Co2 Concentration ◽  
The State ◽  
Small Scale ◽  
The Internet ◽  
Artificial Environment ◽  
The Internet Of Things

To support farmers and improve the quality of crops production, designing of smart greenhouses is becoming indispensable. In this paper, a novel prototype for remote monitoring of a greenhouse is designed. The prototype allows creating an adequate artificial environment inside the greenhouse (e.g., water irrigation, ventilation, light intensity, and CO2 concentration). Thanks to the Internet of things technique, the parameters controlled (air temperature, relative humidity, capacitive soil moisture, light intensity, and CO2 concentration) were measured and uploaded to a designed webpage using appropriate sensors with a low-cost Wi-Fi module (NodeMCU V3). An Android mobile application was also developed using an A6 GSM module for notifying farmers (e.g., sending a warning message in case of any anomaly) regarding the state of the plants. A low-cost camera was used to collect and send images of the plants via the webpage for possible diseases identification and classification. In this context, a deep learning convolutional neural network was developed and implemented into a Raspberry Pi 4. To supply the prototype, a small-scale photovoltaic system was built. The experimental results showed the feasibility and demonstrated the ability of the prototype to monitor and control the greenhouse remotely, as well as to identify the state of the plants. The designed smart prototype can offer real-time remote measuring and sensing services to farmers.

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