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About 10,000 papers for “current intensity”

Fabrication of Current Intensity Convertible CLD of Large Current Intensity for LED Network Application

J. Kieeme, Hwa Jin Park, S. J. Yu et al. · 2012

Abstract: A current intensity convertible CLD chip was fabricated using small and large FET cell configuration. Pinch-off current of 8.82 mA and 11.56 mA were obtained for small and large cell in the CLD chip, respectively. Constant current was fairly maintained until the breakdown voltage of 60 V. Measured knee voltage, Vk were 3.8 V and 4.5 V for small and large cell, respectively. We configured current amplifying chip with parallel connection of each cells, by connecting 8 individual large cells in parallel network, 92.0 mA of current was obtained. The pinch-off constant current of CLD chip was

Cited by 0

Fabrication of Current Intensity Convertible CLD of Large Current Intensity for LED Network Application

Hwa-Jin Park, Soon Jae Yu, K. Anil et al. · Journal of the Korean Institute of Electrical and Electronic Material Engineers · 2012

A current intensity convertible CLD chip was fabricated using small and large FET cell configuration. Pinch-off current of 8.82 mA and 11.56 mA were obtained for small and large cell in the CLD chip, respectively. Constant current was fairly maintained until the breakdown voltage of 60 V. Measured knee voltage, <TEX>$V_k$</TEX> were 3.8 V and 4.5 V for small and large cell, respectively. We configured current amplifying chip with parallel connection of each cells, by connecting 8 individual large cells in parallel network, 92.0 mA of current was obtained. The pinch-off constant current of CLD chip was varied very linearly with respect to the number of parallel connected cell.

Cited by 1Open access

Current monitors for intensity modulated beams

M. Ball, B. Hamilton · AIP conference proceedings · 1995

A beam intensity modulation system (BIMPS), that works in conjunction with the beam splitting system to allow beams of different intensities to be sequentially delivered to two different areas, has already been in use for many years. The operators could not, however, tune the cyclotrons with the BIMPS in operation using the existing beam instrumentation systems in the cyclotron beamlines which consisted mostly of non‐electron‐suppressed stops. Since the BIMPS duty factor (e.g. as low as 1/100 when operating with a 100 μs high intensity (HI) pulse at 10 Hz) usually exceed the ratio of the HI to LOW beam intensities (varying in the range from 10 to 100), the stops would, to first order, merely read out the LOW beam intensity. Thus there existed no way to monitor the HI beam intensity and transmission efficiency unless operating continuously in the HI beam mode. To allow BIMPS operation at all times, a new system of intercepting and nonintercepting beam current monitors have been added to the cyclotron beamlines.The system consists of electron suppressed stops and nonintercepting beam pickups with high output bandwidth of (10 kHz) signal processors to allow accurate sampling of the short duration HI beam pulses. The electronics for the stops are straightforward; there are, however, important technical trade‐off in the design of the nonintercepting system design. The amplifier input voltage noise and relatively low coupling impedance of the nonintercepting pickups cause the minimum detectable HI current to decrease with the square root of the HI beam pulse length; as the pulse length is shortened, the system timing constraints also become more critical. Although the BIMPS is capable of providing beam pulse durations as short at 10 μs, the minimum pulse length for operation was chosen to be 100 μs. The electronics have time constants of 200 μs allowing measurement accuracies of better than a percent. Since the most rapid modulation frequency used for filling the Cooler is 20 Hz (corresponding to 1 transverse cooling time constant) the HI pulse does not begin to significantly contribute to the radiation levels or to the total beam losses in the cyclotrons until the modulation ratio of HI to LOW beam exceeds 50.

Cited by 1

Noise Intensity-Intensity Correlations and the Fourth Cumulant of Current Fluctuations

Jean-Charles Forgues, Fatou Bintou Sane, Blanchard, Simon et al. · arXiv (Cornell University) · 2013

We report measurements of the correlation between intensities of noise at different frequencies on a tunnel junction under ac excitation, which corresponds to two-mode intensity correlations in optics. We observe positive correlation, \emph{i.e.} photon bunching, which exist only for certain relations between the excitation frequency and the two detection frequencies, depending on the dc bias of the sample. We demonstrate that these correlations are proportional to the fourth cumulant of current fluctuations.

Cited by 0Open access

Enhanced angular current intensity from Schottky emitters

Shozo Fujita, T. R. C. WELLS, Wataru Ushio et al. · Journal of Microscopy · 2010

Even though the Schottky emitter is a high-brightness source of choice for electron beam systems, its angular current intensity is substantially lower than that of thermionic cathodes, rendering the emitter impractical for applications that require high beam current. In this study, two strategies were attempted to enhance its angular intensity, and their experimental results are reported. The first scheme is to employ a higher extraction field for increasing the brightness. However, the tip shape transformation was found to induce undesirably elevated emission from the facet edges at high fields. The second scheme exploits the fact that the angular intensity is proportional to the square of the electron gun focal length [Fujita, S. & Shimoyama, H. (2005) Theory of cathode trajectory characterization by canonical mapping transformation. J. Electron Microsc. 54, 331–343], which can be increased by scaling-up the emitter tip radius. A high angular current intensity (JΩ∼ 1.5 mA sr−1) was obtained from a scaled-up emitter. Preliminary performance tests were conducted on an electron probe-forming column by substituting the new emitter for the original tungsten filament gun. The beam current up to a few microamperes was achieved with submicron spatial resolution.

Cited by 16

Low-Intensity Transcranial Current Stimulation in Psychiatry

Noah S. Philip, Brent Nelson, Flavio Frӧhlich et al. · American Journal of Psychiatry · 2017

Neurostimulation is rapidly emerging as an important treatment modality for psychiatric disorders. One of the fastest-growing and least-regulated approaches to noninvasive therapeutic stimulation involves the application of weak electrical currents. Widespread enthusiasm for low-intensity transcranial electrical current stimulation (tCS) is reflected by the recent surge in direct-to-consumer device marketing, do-it-yourself enthusiasm, and an escalating number of clinical trials. In the wake of this rapid growth, clinicians may lack sufficient information about tCS to inform their clinical practices. Interpretation of tCS clinical trial data is aided by familiarity with basic neurophysiological principles, potential mechanisms of action of tCS, and the complicated regulatory history governing tCS devices. A growing literature includes randomized controlled trials of tCS for major depression, schizophrenia, cognitive disorders, and substance use disorders. The relative ease of use and abundant access to tCS may represent a broad-reaching and important advance for future mental health care. Evidence supports application of one type of tCS, transcranial direct current stimulation (tDCS), for major depression. However, tDCS devices do not have regulatory approval for treating medical disorders, evidence is largely inconclusive for other therapeutic areas, and their use is associated with some physical and psychiatric risks. One unexpected finding to arise from this review is that the use of cranial electrotherapy stimulation devices-the only category of tCS devices cleared for use in psychiatric disorders-is supported by low-quality evidence.

Cited by 136Open access

First measurements of continuing current intensity in Brazil

Ferraz, Evandro de Carvalho, Saba, Marcelo Magalhães Fares, Pinto Jr, Osmar · Biblioteca Digital da Memória Científica do INPE (National Institute for Space Research) · 2009

This work presents the first quantitative study of the continuing current (Icc) in negative cloud-to-ground flashes (-CG) in Brazil. The Icc is a low intensity current that follows some return strokes in CG flashes. Their long durations result in large charge transfers that are responsible for most lightning damage associated with thermal effects. In this study, a precise observation of the duration of Icc was obtained using high-speed cameras operating with 1000 to 4000 images per second. In order to measure the intensities of the Icc, an electric field sensor was developed with a sensitivity that could allow the measurement of charge transfers by Icc events occurring up to 30 km away. Time synchronization of the high-speed camera and the BrasilDat (Brazilian Lightning Location System) allowed the determination of the distances of each event. The current intensities measured in Brazil were approximately two times greater than past measurements done in Florida, USA (30 events) and New Mexico, USA (16 events). The charge transfers were approximately three times greater than the previous values obtained in these studies. Maximum measured values for current were higher than 1400 A, and the average was 292 A. Maximum Icc duration was 482 ms and the average was 170 ms. The maximum charge transfer observed was 370 C, and the average was 51 C. The luminosity variation of the lightning channel was also analyzed. The relationship between luminosity and current during Icc proved to be linear in all cases. This result corroborates for the first time for natural lightning, this linearity previously observed for upward lightning in towers. M-components current intensity were measured for the first time in Brazil. The charge transfer of some M-components may be of the order of return strokes without Icc.

Cited by 1Open access

Very low intensity alternating current decreases cell proliferation

Luca Cucullo, Gabriele Dini, Kerri Hallene et al. · Glia · 2005

Electric fields impact cellular functions by activation of ion channels or by interfering with cell membrane integrity. Ion channels can regulate cell cycle and play a role in tumorigenesis. While the cell cycle may be directly altered by ion fluxes, exposure to direct electric current of sufficient intensity may decrease tumor burden by generating chemical products, including cytotoxic molecules or heat. We report that in the absence of thermal influences, low-frequency, low-intensity, alternating current (AC) directly affects cell proliferation without a significant deleterious contribution to cell survival. These effects were observed in normal human cells and in brain and prostate neoplasms, but not in lung cancer. The effects of AC stimulation required a permissive role for GIRK2 (or K(IR)3.2) potassium channels and were mimicked by raising extracellular potassium concentrations. Cell death could be achieved at higher AC frequencies (>75 Hz) or intensities (>8.5 microA); at lower frequencies/intensities, AC stimulation did not cause apoptotic cellular changes. Our findings implicate a role for transmembrane potassium fluxes via inward rectifier channels in the regulation of cell cycle. Brain stimulators currently used for the treatment of neurological disorders may thus also be used for the treatment of brain (or other) tumors.

Cited by 53

Current status of clinical high-intensity focused ultrasound

Joo Ha Hwang, Lawrence A. Crum · 2009

High-intensity focused ultrasound (HIFU) is being promoted as a noninvasive method to treat certain primary solid tumors, metastatic disease, and enhance drug delivery. The field of medicine is evolving towards increasing use of noninvasive and minimally invasive therapies such as HIFU. This article provides an overview of current clinical applications of HIFU and future requirements to expand the clinical applications of this technique.

Cited by 27