207 research outputs found

    Effect of Interlayer Coupling on Ultrafast Charge Transfer from Semiconducting Molecules to Mono- and Bilayer Graphene

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    Graphene is used as flexible electrodes in various optoelectronic devices. In these applications, ultrafast charge transfer from semiconducting light absorbers to graphene can impact the overall device performance. Here, we propose a mechanism in which the charge-transfer rate can be controlled by varying the number of graphene layers and their stacking. Using an organic semiconducting molecule as a light absorber, the charge-transfer rate to graphene is measured by using time-resolved photoemission spectroscopy. Compared to graphite, the charge transfer to monolayer graphene is about 2 times slower. Surprisingly, the charge transfer to Aāˆ’Bā€“stacked bilayer graphene is slower than that to both monolayer graphene and graphite. This anomalous behavior disappears when the two graphene layers are randomly stacked. The observation is explained by a charge-transfer model that accounts for the band-structure difference in mono- and bilayer graphene, which predicts that the charge-transfer rate depends nonintuitively on both the layer number and stacking of graphene

    Effect of the Interfacial Energy Landscape on Photoinduced Charge Generation at the ZnPc/MoS2 Interface

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    This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society, copyright Ā© American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/jacs.9b05893

    Public healthcare financing and provision in Hong Kong : a public-private partnership approach

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    published_or_final_versionPolitics and Public AdministrationMasterMaster of Public Administratio

    Thermal comfort and energy performance of public rental housing under typical and near-extreme weather conditions in Hong Kong

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    Ā© 2017 Elsevier B.V. Building performance evaluation is crucial for sustainable urban developments. In high-density cities, occupants suffer from poor living conditions due to building overheating, especially during increasingly frequent near-extreme summer conditions caused by climate change. To represent this situation, the summer reference year weather data was employed for building simulations using DesignBuilder. This study aims to evaluate the thermal comfort and energy consumption of four typical public rental housing (PRH) building types in Hong Kong. For free-running flats, results show generally higher air temperatures in the oldest PRH type (Slab) with a compact linear building form and the most sensitive response to outdoor temperature changes for another older PRH type (Trident) with a Y-shaped design, possibly owing to its high wall conductivity. Occupants in all building types experience a ???10% increase in the proportion of discomfort hours when compared to results for typical summer conditions, but overheating is the most severe in Slab type PRH. Following an initial assessment of the cooling energy usage, a simple sensitivity test was conducted to explore the potential energy savings by various passive design strategies, including shading and reducing the exposed cooled space. A cross-shaped building form also appears to be more energy efficient. These findings, complemented by further parametric analyses, may prove useful when designing buildings for climate change

    Blind Navigation System By Using RFID And Digital Compass Technology

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    This paper describe the RFID technology which is applied to guide the visually impaired person at indoor and outdoor environment. In order to provide an efficient and user-friendly navigation tools, it is proposed to design and develop a navigation device using RFID network with the digital compass to guide visually impaired person walking properly via audio navigation. The idea of positioning and localization with digital compass and direction guiding through voice commands is implemented in this design. The study focuses on the calibration of the compass and relocates the visually impaired person back to the normal route if they are out of the direction. Data analysis will be done during the evaluation of the navigation device and assessment will be made improve the performance of the device. This project is beneficial to visually impaired person because the navigation device designed with voice commands will helps them to have a better, safer and comfortable travel

    A comparative study on the indoor thermal comfort and energy consumption of typical public rental housing types under near-extreme summer conditions in Hong Kong

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    Ā© 2017 The Authors. Published by Elsevier Ltd. Residents of the dense urban environment in Hong Kong suffer from poor living conditions due to building overheating, especially during near-extreme summer conditions. In this study, the thermal comfort and energy performance of typical public rental housing (PRH) building types were simulated using DesignBuilder. Results show that the oldest Slab type PRH, which has a compact building form, has the highest indoor air temperature, yet the lowest cooling energy demand. On the other hand, the Trident type PRH, with the largest external wall U-value, performs the worst overall and is the most responsive to outdoor temperature changes

    Hong Kong Renal Registry Report 2012

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    SummaryThis report examined the characteristics and trends of dialysis and renal transplant patients among the resident population of Hong Kong who were managed by hospitals or dialysis centers of the Hospital Authority, and accounted for approximately 95% of all patients receiving renal replacement therapies (RRTs) in the territory. Patients receiving RRTs solely in the private sector were not included in this report. Data trends from 1996 to 2011 are presented. In 2011, 1115 new patients were accepted into RRT programs, and the incident rate was 157 patients per million populations (pmp). An increasing trend was noted. The incident rate was 95.1Ā pmp at the commencement of the annual report in 1996. The point prevalence on December 31, 2012 was 8197 with a prevalence rate of 1152.5Ā pmp. Overall, there were 3573 patients (43.6%) on peritoneal dialysis (PD) and 1246 patients (15.2%) on hemodialysis (HD), and 3378 patients (41.2%) were living with a functioning renal transplant. The PD/HD ratio was 74.2:25.8. The ā€œPD Firstā€ policy was continued. The overall mortality rate among RRT patients was 9.95 patients per 100 patient-years exposed. There was a decreasing trend in mortality among PD patients. Infection and cardiovascular complications were the most common causes of death. Renal transplant was the modality with the best survival rates. The 5Ā years cumulative patient survival rate for patients on transplant treatment was 89.6%, whereas the corresponding patient survival rates for PD and HD patients were 50.7% and 55.7%, respectively. More than 70% of RRT patients with reports on rehabilitation were active and had normal daily activities
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