Controllable assembly and properties of ZnO nanowires

2015 ◽  
Vol 32 (2) ◽  
pp. 52-54 ◽  
Author(s):  
Bo Zhao ◽  
Nan Wang ◽  
Guohua Jiang
Keyword(s):  
High Frequency ◽  
Design Methodology ◽  
Uv Light ◽  
Zno Nanowires ◽  
Exhaled Breath ◽  
Zno Nanowire ◽  
Uv Detector ◽  
Content Type ◽  
Current Voltage ◽  
Stable Performance

Purpose – The purpose of this paper is to arrange zinc oxide (ZnO) nanowires into an appropriate position on electrodes and to research the properties of ZnO nanowires. Design/methodology/approach – In this paper, dielectrophoresis (DEP) was used to fabricate ZnO nanowire devices, and the responses to temperature, ultraviolet (UV) light and breath of the device were studied. Findings – The number of the bridged nanowires is increased with alternating current voltage. ZnO nanowires demonstrate a good photoconductivity illuminated by 365-nm UV light, and show a stable performance in monitoring unnatural breath of high frequency and low strength. Originality/value – In this paper, DEP is a promising method for controllable assembly of ZnO nanowires. ZnO nanowires demonstrate a good response to 365-nm UV light and exhaled breath, which show great potential application in UV detector and medical monitor.

ZnO nanowire UV photodetector with multiple channels

2018 ◽  
Vol 35 (1) ◽  
pp. 18-23 ◽  
Author(s):  
Guohua Jiang ◽  
Dongmei Zhao ◽  
Bo Zhao
Keyword(s):  
Design Methodology ◽  
Uv Light ◽  
Alternating Current ◽  
Optoelectronic Properties ◽  
Multiple Channels ◽  
Zno Nanowire ◽  
Uv Photodetector ◽  
Content Type ◽  
Uv Photodetectors ◽  
Current Voltage

Purpose The purpose of this paper is to investigate the optoelectronic properties of the multichannel ZnO UV photodetectors. Design/methodology/approach ZnO nanowires were assembled by dielectrophoresis for the UV photodetectors. Different ZnO channels were adjusted by different alternating current voltages and investigated for UV optoelectronic properties. Findings The number of the ZnO channels increases with the enhancing alternating current voltage. Optimum performance of the UV photodetectors is obtained with more channels. Originality/value Dielectrophoresis is a promising method for controllable assembly of multichannel ZnO photodetectors. ZnO photodetectors with more channels demonstrate a good response to 380-nm UV light, which shows great potential application in UV photodetector.

Fabrication of High Sensitive UV Photodetector Based on n-ZnO Nanowire/n-Porous-Si Heterojunction

NANO ◽  
2017 ◽  
Vol 12 (04) ◽  
pp. 1750044 ◽  
Author(s):  
M. M. Haji Shahkarami ◽  
J. Koohsorkhi ◽  
H. Ghafoori Fard
Keyword(s):  
Uv Radiation ◽  
Uv Light ◽  
High Sensitivity ◽  
Significant Rise ◽  
Zno Nanowires ◽  
X Ray Diffraction ◽  
Uv Detector ◽  
Voltage Curve ◽  
Current Voltage ◽  
Current Voltage Curve

In this paper, we have reported the high sensitive UV detector using ZnO nanowires prepared on porous silicon (PS). The aligned naturally doped n-type zinc oxide (ZnO) nanowires were grown on both PS and n-Si(100) substrates to produce isotype heterojunctions using hydrothermal method. The length of the nanowires ranges 3–4[Formula: see text][Formula: see text]m and the diameter 150–200[Formula: see text]nm. Grown ZnO nanowires on PS substrate has lower reflectivity value compared with Si substrate. The electrical behavior of such devices has been examined at different intensities of UV radiation. The current–voltage curve of the isotype heterojunction shows rectifying behavior in a dark environment. Under UV light, the current was increased by using PS instead of n-Si under reverse bias. The I–V characteristics of the device show a significant rise in the current for low intensity of UV radiation evidencing the high sensitivity of the reported structure. The sensitivity for such devices is obtained, [Formula: see text] and [Formula: see text] at UV radiation of 1.5[Formula: see text]mW/cm2 intensity at bias voltage of −0.75 V for three proposed structures. The samples have been analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) to investigate their structures and geometries.

Recent civil and criminal enforcement action involving high frequency trading

2015 ◽  
Vol 16 (1) ◽  
pp. 5-12 ◽  
Author(s):  
Matthew Rossi ◽  
Greg Deis ◽  
Jerome Roche ◽  
Kathleen Przywara
Keyword(s):  
High Frequency ◽  
Design Methodology ◽  
High Frequency Trading ◽  
Content Type ◽  
Enforcement Action ◽  
The Past ◽  
Trading Patterns ◽  
Federal Prosecutor ◽  
Enforcement Activity ◽  
Practical Implications

Purpose – To alert high frequency trading firms to the increased regulation and prosecution of manipulative trading practices during 2014 and early 2015. Design/methodology/approach – Reviews four significant proceedings against high frequency trading firms (and/or individuals employed by such firms) and other developments from the relevant government agencies as a possible preview of the enforcement and prosecution of high frequency trading practices in 2015. Provides advice to high frequency trading firms on how to decrease the risk of regulatory or criminal actions against them in this changing environment. Findings – Although the focus on high frequency trading has only recently begun to intensify, firms should be aware of the increased enforcement activity of the past year. These actions, both regulatory and criminal, have already resulted in large penalties and have helped initiate a strengthening of rules and regulations regarding manipulative trading practices, of which firms need to be aware and stay current. Practical implications – High frequency trading firms should be aware of the recent regulatory and criminal actions in order to better evaluate their own practices and controls, to ensure that their trading patterns do not resemble manipulative practices, and to avoid similar actions. Originality/value – Practical guidance from experienced litigators and securities regulatory lawyers, including a former SEC Assistant Chief Litigation Counsel and a former federal prosecutor, that consolidates and describes several recent actions and developments in one piece.

Stock market predictability

2014 ◽  
Vol 31 (4) ◽  
pp. 354-370 ◽  
Author(s):  
Silvio John Camilleri ◽  
Christopher J. Green
Keyword(s):  
Stock Market ◽  
High Frequency ◽  
Serial Correlation ◽  
Design Methodology ◽  
High Frequency Data ◽  
Frequency Data ◽  
Content Type ◽  
Lag Effects ◽  
Daily Data ◽  
Indian Stock Market

Purpose – The main objective of this study is to obtain new empirical evidence on non-synchronous trading effects through modelling the predictability of market indices. Design/methodology/approach – The authors test for lead-lag effects between the Indian Nifty and Nifty Junior indices using Pesaran–Timmermann tests and Granger-Causality. Then, a simple test on overnight returns is proposed to infer whether the observed predictability is mainly attributable to non-synchronous trading or some form of inefficiency. Findings – The evidence suggests that non-synchronous trading is a better explanation for the observed predictability in the Indian Stock Market. Research limitations/implications – The indication that non-synchronous trading effects become more pronounced in high-frequency data suggests that prior studies using daily data may underestimate the impacts of non-synchronicity. Originality/value – The originality of the paper rests on various important contributions: overnight returns is looked at to infer whether predictability is more attributable to non-synchronous trading or to some form of inefficiency; the impacts of non-synchronicity are investigated in terms of lead-lag effects rather than serial correlation; and high-frequency data is used which gauges the impacts of non-synchronicity during less active parts of the trading day.

High-frequency displacement current transformer with just one winding

2019 ◽  
Vol 38 (4) ◽  
pp. 1141-1153 ◽  
Author(s):  
Yahia Achour ◽  
Jacek Starzyński
Keyword(s):  
High Frequency ◽  
Design Methodology ◽  
Current Transformer ◽  
Magnetic Core ◽  
Displacement Current ◽  
Frequency Range ◽  
Content Type ◽  
The Core ◽  
Difference Time ◽  
Secondary Winding

Purpose This paper aims to describe a new concept of transformer based on the displacement current. The paper shows how this idea can be translated into reality and presents an example of a working design. Design/methodology/approach The authors replace the primary winding of the transformer with a capacitor. The displacement current between the capacitor plates induces a magnetic flux in the core. This flux in turn induces electromotive force in the classical secondary winding. Findings The basic mathematical aspects illustrated by results obtained from a simulation developed using a commercial software ANSYS-HFSS are given. The saturation of the magnetic core due to the applied high-frequency range is investigated and simulated using a finite difference time domain code implemented in MATLAB. A prototype transformer was built and tested; the obtained results confirm the previous ones from simulations. Originality/value A new concept of the single winding transformer was used as a pulse forming circuit.

High frequency of HBV in HIV-infected prisoners in Mozambique

2019 ◽  
Vol 15 (1) ◽  
pp. 58-65
Author(s):  
Angelo Augusto ◽  
Orvalho Augusto ◽  
Atija Taquibo ◽  
Carina Nhachigule ◽  
Narcisa Siyawadya ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
High Frequency ◽  
Design Methodology ◽  
Content Type ◽  
B Virus ◽  
First Time ◽  
Hiv Seropositive

Purpose The purpose of this paper is to determine the prevalence of hepatitis B virus (HBV) among 448 HIV-infected prisoners from 32 prisons in Mozambique. Design/methodology/approach All HIV seropositive prisoners were screened for HBV. Findings Of the 448 HIV seropositive prisoners, 51 (11.4 percent, 95%CI: 9.3–13.9 percent) were HBsAg-positive and was significantly higher in prisoners aged<25 years. Originality/value Data from this study show for the first time that the frequency of HBV among HIV-infected prisoners is high, suggesting that immediate interventions are needed during incarceration.

High-frequency traders: a review of the challenges in registering them as dealers

2014 ◽  
Vol 15 (3) ◽  
pp. 3-9
Author(s):  
Mark Fitterman ◽  
Ignacio Sandoval
Keyword(s):  
High Frequency ◽  
Design Methodology ◽  
Analytical Framework ◽  
Securities And Exchange Commission ◽  
Content Type ◽  
Market Participants ◽  
Concise Overview

Purpose – To describe some of the challenges that the Securities and Exchange Commission (SEC) will face in requiring that high-frequency traders register as dealers. Design/methodology/approach – This paper provides a brief overview of the dealer-trader distinction, an analytical framework under which some high-frequency traders have avoided registration with the SEC as dealers. It then explains the difficulties the SEC will encounter in bringing high-frequency traders within its regulatory umbrella as dealers. In particular, the paper outlines some of the interpretive challenges the SEC encounter as well as challenges to justifying the economics of any proposal. Findings – While the SEC has yet to formally propose rules in this area, the interpretive vehicle it uses could have repercussions for other market participants that rely on the dealer-trader distinction to avoid having to register as dealers with the SEC. Originality/value – The paper provides practical insights into the issues the SEC will have to address if it proposes to bring high-frequency traders within its regulatory umbrella as dealers. In addition, it provides a concise overview of the dealer-trader distinction based on statements by the SEC and its staff.

ZnO Nanowire/p-GaN Heterojunction LEDs

2007 ◽  
Vol 1018 ◽  
Author(s):  
Heiko O. Jacobs ◽  
Jesse Cole ◽  
Amir M. Dabiran ◽  
Heiko O. Jacobs
Keyword(s):  
Reverse Bias ◽  
Forward Bias ◽  
Zno Nanowires ◽  
Hole Injection ◽  
Zno Nanowire ◽  
Defect States ◽  
Light Emitting ◽  
Current Voltage ◽  
Distinct Color ◽  
Two Peaks

AbstractThis article reports forward and reverse biased emission in vertical ZnO nanowire/p-GaN heterojunction light emitting diodes (LEDs) grown out of solution on Mg-doped p-GaN films. The electroluminescence spectra under forward and reverse bias are distinctly different. Forward bias showed two peaks centered around 390 nm and 585 nm, while reverse bias showed a single peak at 510 nm. Analysis of the current-voltage characteristics and electroluminescence spectra is presented to determine the transport mechanism and location of electron hole recombination. Reverse bias transport and luminescence are attributed to hot-hole injection from the ZnO nanowires into the GaN film through tunneling breakdown. Forward bias transport and luminescence are attributed to hole injection from the GaN into the ZnO and recombination at defect states inside the ZnO yielding distinct color variations between individual wires. Major resistive losses occurred in the GaN lateral thin film connecting to the vertical ZnO nanowires.

Performance simulation and testing of capacitive micro-machined ultrasonic transducer

Sensor Review ◽  
2019 ◽  
Vol 39 (4) ◽  
pp. 554-566
Author(s):  
Rui Zhang ◽  
Lei Zhao ◽  
Dan Xie ◽  
Jinlong Song ◽  
Wendong Zhang ◽  
...  
Keyword(s):  
High Frequency ◽  
Design Methodology ◽  
Ultrasonic Transducer ◽  
Dynamic Performance ◽  
Transimpedance Amplifier ◽  
Echo Signal ◽  
Performance Simulation ◽  
Content Type ◽  
Detection Circuit ◽  
Dynamic Performance Analysis

Purpose This study aims to simulate and test the performance of a transmitting and receiving capacitive micro-machined ultrasonic transducer (CMUT). Aimed at detecting demand of the CMUT, a matched integrated adjustment circuit was designed through analyzing processing methods of transducer’s weak echo signal. Design/methodology/approach Based on the analysis of CMUT array structure and work principle, the CMUT units are designed and the dynamic performance analysis of SIMULINK is given according to the demand of underwater detecting. A transceiver isolation circuit is used to make transmission mode and receiving mode separate. A detection circuit is designed based on the transimpedance amplifier to achieve extraction of high-frequency and weak signal. Findings Through experimentation, the effectiveness of the CMUT performance simulation and the transceiver integrated adjustment circuit were verified. In addition, the test showed that CMUT with 400 kHz frequency has wider bandwidth and better dynamic characteristics than other similar transducers. Originality/value This paper provides a theoretical basis and design reference for the development and application of CMUT technology.

Fiscal and monetary response to the COVID-19 pandemic in India

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Justina Jose ◽  
Priyanka Mishra ◽  
Rahul Pathak
Keyword(s):  
High Frequency ◽  
Design Methodology ◽  
Resource Constraints ◽  
Economic Conditions ◽  
Policy Response ◽  
Content Type ◽  
Long Run ◽  
Fiscal Space ◽  
The Government ◽  
Consumption Taxes

PurposeThis article examines the preliminary impact of the Sars-CoV-2 pandemic on India's economic and budgetary landscape – the most affected developing country from the first wave of the pandemic. It also includes a discussion of the monetary and fiscal responses adopted and the challenges faced in formulating the response to the pandemic.Design/methodology/approachUsing high-frequency economic and fiscal indicators, this article evaluates the economic impact of the pandemic on the Indian economy. Further, it uses data from government sources and news to highlight the measures adopted at the national and subnational level in response to the pandemic.FindingsThe difficult economic conditions prior to the pandemic limited the fiscal space available to the government. As a result, the national and subnational governments have been cautious of accumulating excessive debt and have primarily responded with liquidity-enhancing measures, in addition to some fiscal measures for the most vulnerable. Overdependence on consumption taxes has led to unprecedented revenue shortfalls prompting the exploration of new avenues for revenue generation and implementation of austerity measures – some of which may be counterproductive in the long run.Originality/valueThe paper highlights the policy response of the largest democracy that has been hit hard by the pandemic. It also highlights various institutional and resource constraints that influenced the policies adopted. India's experience in responding to the virus could provide lessons for other developing countries.

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