235 research outputs found

    Properties of Si-SiO2 interface traps due to low-energy Ar+ backsurface bombardment in n-channel nitrided MOSFETs

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    Flicker noise in backsurface gettered, nitrided n-channel MOSFETs is characterized over a wide range of temperatures and biases. The gettering time ranged from 10 to 40 minutes. The noise power spectra for devices with different gettering times are compared to the ungettered devices which serve as the control. It is found that flicker noise is reduced by backsurface gettering for short gettering times. A rebound in the noise magnitude is observed for long gettering times. Investigations of the temperature dependencies of the noise power spectra indicates that the low-frequency noise arises from thermal activation of carriers to traps at the Si-SiO2 interface. Backsurface gettering results in the modification of the energy distribution of the interface traps, probably due to stress relaxation at the Si-SiO2 interface.published_or_final_versio

    Doping of GaN by Mg diffusion

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    A new model using routinely available clinical parameters to predict significant liver fibrosis in chronic hepatitis B

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    Objective: We developed a predictive model for significant fibrosis in chronic hepatitis B (CHB) based on routinely available clinical parameters. Methods: 237 treatment-naïve CHB patients [58.4% hepatitis B e antigen (HBeAg)-positive] who had undergone liver biopsy were randomly divided into two cohorts: training group (n = 108) and validation group (n = 129). Liver histology was assessed for fibrosis. All common demographics, viral serology, viral load and liver biochemistry were analyzed. Results: Based on 12 available clinical parameters (age, sex, HBeAg status, HBV DNA, platelet, albumin, bilirubin, ALT, AST, ALP, GGT and AFP), a model to predict significant liver fibrosis (Ishak fibrosis score ≥3) was derived using the five best parameters (age, ALP, AST, AFP and platelet). Using the formula log(index+1) = 0.025+0.0031(age)+0.1483 log(ALP)+0.004 log(AST)+0.0908 log(AFP+1)-0.028 log(platelet), the PAPAS (Platelet/Age/Phosphatase/AFP/AST) index predicts significant fibrosis with an area under the receiving operating characteristics (AUROC) curve of 0.776 [0.797 for patients with ALT <2×upper limit of normal (ULN)] The negative predictive value to exclude significant fibrosis was 88.4%. This predictive power is superior to other non-invasive models using common parameters, including the AST/platelet/GGT/AFP (APGA) index, AST/platelet ratio index (APRI), and the FIB-4 index (AUROC of 0.757, 0.708 and 0.723 respectively). Using the PAPAS index, 67.5% of liver biopsies for patients being considered for treatment with ALT <2×ULN could be avoided. Conclusion: The PAPAS index can predict and exclude significant fibrosis, and may reduce the need for liver biopsy in CHB patients. © 2011 Seto et al.published_or_final_versio

    Numerical simulations for a typical train fire in China

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    Author name used in this publication: W. K ChowAuthor name used in this publication: N. K. Fong2010-2011 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Innovative Virtual Reality (VR) Application for Preventing of Falls among Chinese Older Adults: A Usability and Acceptance Exploratory Study

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    Objective. Full immersive virtual reality (VR) technology shows potential for reducing the risks of falls in older adults. There is yet little evidence to support the usability and acceptance on using VR technology application in community aged care service. The study reports on research that aims to address that gap by evaluating the usefulness and acceptance of using an innovative VR application among Chinese older adults from Hong Kong. Methods. A single-arm exploratory study was conducted to evaluate how the participants experienced the use of a fully immersive cave automatic virtual environment (CAVE) VR program on fall prevention. Thirty-one participants were recruited by convenience sampling based on their fall concerns and potential risk of falls. The participants completed 16 training sessions over eight weeks using the VR CAVE application. They were asked to complete a VR usability questionnaire (HK-version) based on the Technology Acceptance Model and previous research, and they took fall risk assessments at the pretest, posttest, and follow-up. Results. The participants’ group significantly showed improvements in reducing the risk factors of falls including balance, functional mobility, walking speed, and fear of falling after VR intervention. Perceived usefulness (PU), perceived enjoyment (PE), user experience (UE), and intention to use (IU) had an overall significant change at different time points. These are important factors to influence the participants’ acceptance of the use of VR technology applications. Perceived ease of use (PEOU) and social norms (SNs) had an inconsistent result, and some items had low validity. The findings indicated a positive training effect on fall prevention and high acceptance of the adoption of the VR technology application. Conclusion. This study supports the growing evidence on the usefulness and acceptance of using full immersive VR training on fall prevention among Chinese older adults. They perceived that the VR CAVE application was useful and innovative as an effective fall prevention training. Technically, the application of VR CAVE technology faces many challenges and is not easily manageable under COVID-19 restrictions and the limitation on technological adaptation for older adults. However, investment in full immersive VR technology application is supported for future adoption in aged care and rehabilitation services.</jats:p

    Constructal design of pedestrian evacuation from an area

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    Author name used in this publication: Lui, C. H.Author name used in this publication: Fong, N. K.Author name used in this publication: Chow, W. K.2012-2013 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Constructal design for pedestrian movement in living spaces : evacuation configurations

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    Author name used in this publication: C. H. LuiAuthor name used in this publication: N. K. FongAuthor name used in this publication: S. LorentAuthor name used in this publication: A. BejanAuthor name used in this publication: W. K. Chow2011-2012 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Nitrogen doped-ZnO/n-GaN heterojunctions

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    Nitrogen-doped ZnO nanorods were prepared by electrodeposition using two different Zn precursors (zinc nitrate and zinc acetate), while all other growth conditions (dopant precursor, concentration, growth temperature, and bias) were identical. We have shown that the precursor used affects the properties of the ZnO nanorods, and that the presence of rectifying properties in n-GaN/N:ZnO heterojunctions is strongly related to the use of nitrate precursor for ZnO growth. The difference in the properties of ZnO obtained from two precursors is attributed to the differences in native defect and impurity concentrations, which could affect the electronic properties of the samples. © 2011 American Institute of Physics.published_or_final_versio

    Solution-based growth of ZnO nanorods for light-emitting devices: Hydrothermal vs. electrodeposition

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    ZnO nanorods have been grown by two inexpensive, solution-based, low-temperature methods: hydrothermal growth and electrodeposition. Heterojunction n-ZnO nanorods/p-GaN light-emitting diodes have been studied for different nanorod growth methods and different preparation of the seed layer. We demonstrate that both the nanorod properties and the device performance are strongly dependent on the growth method and seed layer. All the devices exhibit light emission under both forward and reverse bias, and the emission spectra can be tuned by ZnO nanorod deposition conditions. Electrodeposition of rods or a seed layer results in yellow emission, while conventional hydrothermal growth results in violet emission. © The Author(s) 2010. This article is published with open access at Springerlink.com.published_or_final_versionSpringer Open Choice, 01 Dec 201
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