Hawking Radiation Under Generalized Uncertainty Principle

The generalized uncertainty relation is expected to be an essential element in a theory of quantum gravity. In this work, we examine its effect on the Hawking radiation of a Schwarzschild black hole formed from collapse by incorporating a minimal uncertainty length scale into the radial coordinate of the background. This is implemented in both the ingoing Vaidya coordinates and a family of freely falling coordinates. We find that, regardless of the choice of the coordinate system, Hawking radiation is turned off at around the scrambling time. Interestingly, this phenomenon occurs while the Hawking temperature remains largely unmodified.Comment: 23 pages, 1 figur

UV Dispersive Effects on Hawking Radiation

We revisit the connection between Hawking radiation and high-frequency dispersions for a Schwarzschild black hole following the work of Brout et al.. After confirming the robustness of Hawking radiation for monotonic dispersion relations, we consider non-monotonic dispersion relations that deviate from the standard relation only in the trans-Planckian domain. Contrary to the common belief that Hawking radiation is insensitive to UV physics, it turns out that Hawking radiation is subject to significant modifications after the scrambling time. Depending on the UV physics at the singularity, the amplitude of Hawking radiation could diminish after the scrambling time, while the Hawking temperature remains the same. Our finding is thus not contradictory to earlier works regarding the robustness of Hawking temperature.Comment: 24 pages, 8 figure

Seasonal variations of C-1-C-4 alkyl nitrates at a coastal site in Hong Kong: Influence of photochemical formation and oceanic emissions

Five C-1-C-4 alkyl nitrates (RONO2) were measured at a coastal site in Hong Kong in four selected months of 2011 and 2012. The total mixing ratios of C-1-C-4 RONO2 (Sigma 5RONO2) ranged from 15.4 to 143.7 pptv with an average of 65.9 +/- 33.0 pptv. C-3-C-4 RONO2 (2-butyl nitrate and 2-propyl nitrate) were the most abundant RONO2 during the entire sampling period. The mixing ratios of C-3-C-4 RONO2 were higher in winter than those in summer, while the ones of methyl nitrate (MeONO2) were higher in summer than those in winter. Source analysis suggests that C-2-C-4 RONO2 were mainly derived from photochemical formation along with biomass burning (58.3-71.6%), while ocean was a major contributor to MeONO2 (53.8%) during the whole sampling period. The photochemical evolution of C-2-C-4 RONO2 was investigated, and found to be dominantly produced by the parent hydrocarbon oxidation. The notable enrichment of MeONO2 over C-3-C-4 RONO2 was observed in a summer episode when the air masses originating from the South China Sea (SCS) and MeONO2 was dominantly derived from oceanic emissions. In order to improve the accuracy of ozone (O-3) prediction in coastal environment, the relative contribution of RONO2 from oceanic emissions versus photochemical formation and their coupling effects on O-3 production should be taken into account in future studies. (C) 2017 Elsevier Ltd. All rights reserved

以生物多樣性指標評估集水區崩塌地治理優選順序

The abundance of endemic species in Taiwan is a great natural treasure accomplished by a diverse altitude ranges due to violent tectonic activities and humid tropical weather conditions with ocean surrounded. With the characteristics of few flatlands, the slope lands are inevitable and have been developed for economic and social requirement gradually, which has caused habitation shrinking of animal and plant. Furthermore, Taiwan also suffers disasters such as striking of torrential rains and typhoons during summer season annually, and is vulnerable to landslide because of fragile geology which threats to the living things. Thus, to enhance the efficiency of vegetation recovery in landslide area can benefit the habitats of species. Typhoon Morakot induced landslides and vegetation recovery rate in Kao-Ping watershed can be quickly extracted and/or derived from the satellite images in this study. The biodiversity index established in the database of the watershed can then be applied to assess the treatment priority of landslides. The result shows that the highest landslide rate in Chi-Shan and Lao-Nong watersheds are Xiao-Lin and Ching-Shui Xi sub-watersheds respectively. For vegetation recovery rate, the downstream area is higher than upstream area. For treatment priority, the top 10 of sub-watersheds almost distribute in Lao-Nong watershed. It hopes that the result could provide the related authorities as the references of environmental restoration.台灣雖位處北回歸線，但因造山運動拱起4,000 公尺海拔落差，使台灣物種跨越熱帶、溫帶及寒帶，且四面環海及高溫多雨之島嶼氣候，孕育出許多台灣特有種生物，然台灣因高山多、平地少，在高人口密度下，居民為了生活不得不開發山坡地之原始森林，此舉壓縮了動、植物之生存空間，此外，台灣山高且地質破碎，夏季之暴雨或颱風易造成大規模之崩塌，除對當地居民造成威脅外，亦影響其他物種之生存環境，為此，如何加速崩塌地之植生復育，將有助於恢復各物種之棲地。本研究以莫拉克風災為事件，利用該事件前後期之衛星影像萃取集水區崩塌區位，另計算災後集水區植生復育良窳之熱點區位，最後以生物多樣性指數配合崩塌率及植生復育率評估集水區崩塌地治理之優選順序。研究結果顯示，旗山溪及荖濃溪集水區中崩塌率最高之子集水區分別為小林及清水溪；植生復育率則為下游高於上游區位；整體崩塌地治理優先順序中，得分最高之前10 處主要分布於荖濃溪集水區。期本研究之結果可作為相關生態保育單位於環境復育之參考

Ligand-assisted cation-exchange engineering for high-efficiency colloidal Cs1−xFAxPbI3 quantum dot solar cells with reduced phase segregation

The mixed caesium and formamidinium lead triiodide perovskite system (Cs1−xFAxPbI3) in the form of quantum dots (QDs) offers a pathway towards stable perovskite-based photovoltaics and optoelectronics. However, it remains challenging to synthesize such multinary QDs with desirable properties for high-performance QD solar cells (QDSCs). Here we report an effective oleic acid (OA) ligand-assisted cation-exchange strategy that allows controllable synthesis of Cs1−xFAxPbI3 QDs across the whole composition range (x = 0–1), which is inaccessible in large-grain polycrystalline thin films. In an OA-rich environment, the cross-exchange of cations is facilitated, enabling rapid formation of Cs1−xFAxPbI3 QDs with reduced defect density. The hero Cs0.5FA0.5PbI3 QDSC achieves a certified record power conversion efficiency (PCE) of 16.6% with negligible hysteresis. We further demonstrate that the QD devices exhibit substantially enhanced photostability compared with their thin-film counterparts because of suppressed phase segregation, and they retain 94% of the original PCE under continuous 1-sun illumination for 600 h

A survey of localization in wireless sensor network

Localization is one of the key techniques in wireless sensor network. The location estimation methods can be classified into target/source localization and node self-localization. In target localization, we mainly introduce the energy-based method. Then we investigate the node self-localization methods. Since the widespread adoption of the wireless sensor network, the localization methods are different in various applications. And there are several challenges in some special scenarios. In this paper, we present a comprehensive survey of these challenges: localization in non-line-of-sight, node selection criteria for localization in energy-constrained network, scheduling the sensor node to optimize the tradeoff between localization performance and energy consumption, cooperative node localization, and localization algorithm in heterogeneous network. Finally, we introduce the evaluation criteria for localization in wireless sensor network

A Single-Walled Carbon Nanotube Network Gas Sensing Device

The goal of this research was to develop a chemical gas sensing device based on single-walled carbon nanotube (SWCNT) networks. The SWCNT networks are synthesized on Al2O3-deposted SiO2/Si substrates with 10 nm-thick Fe as the catalyst precursor layer using microwave plasma chemical vapor deposition (MPCVD). The development of interconnected SWCNT networks can be exploited to recognize the identities of different chemical gases by the strength of their particular surface adsorptive and desorptive responses to various types of chemical vapors. The physical responses on the surface of the SWCNT networks cause superficial changes in the electric charge that can be converted into electronic signals for identification. In this study, we tested NO2 and NH3 vapors at ppm levels at room temperature with our self-made gas sensing device, which was able to obtain responses to sensitivity changes with a concentration of 10 ppm for NO2 and 24 ppm for NH3

Maritime threat response

This report was prepared by Systems Engineering and Analysis Cohort Nine (SEA-9) Maritime Threat Response, (MTR) team members.Background: The 2006 Naval Postgraduate School (NPS) Cross-Campus Integrated Study, titled “Maritime Threat Response” involved the combined effort of 7 NPS Systems Engineering students, 7 Singaporean Temasek Defense Systems Institute (TDSI) students, 12 students from the Total Ship Systems Engineering (TSSE) curriculum, and numerous NPS faculty members from different NPS departments. After receiving tasking provided by the Wayne E. Meyer Institute of Systems Engineering at NPS in support of the Office of the Assistant Secretary of Defense for Homeland Defense, the study examined ways to validate intelligence and respond to maritime terrorist attacks against United States coastal harbors and ports. Through assessment of likely harbors and waterways to base the study upon, the San Francisco Bay was selected as a representative test-bed for the integrated study. The NPS Systems Engineering and Analysis Cohort 9 (SEA-9) Maritime Threat Response (MTR) team, in conjunction with the TDSI students, used the Systems Engineering Lifecycle Process (SELP) [shown in Figure ES-1, p. xxiii ] as a systems engineering framework to conduct the multi-disciplinary study. While not actually fabricating any hardware, such a process was well-suited for tailoring to the team’s research efforts and project focus. The SELP was an iterative process used to bound and scope the MTR problem, determine needs, requirements, functions, and to design architecture alternatives to satisfy stakeholder needs and desires. The SoS approach taken [shown in Figure ES-2, p. xxiv ]enabled the team to apply a systematic approach to problem definition, needs analysis, requirements, analysis, functional analysis, and then architecture development and assessment.In the twenty-first century, the threat of asymmetric warfare in the form of terrorism is one of the most likely direct threats to the United States homeland. It has been recognized that perhaps the key element in protecting the continental United States from terrorist threats is obtaining intelligence of impending attacks in advance. Enormous amounts of resources are currently allocated to obtaining and parsing such intelligence. However, it remains a difficult problem to deal with such attacks once intelligence is obtained. In this context, the Maritime Threat Response Project has applied Systems Engineering processes to propose different cost-effective System of Systems (SoS) architecture solutions to surface-based terrorist threats emanating from the maritime domain. The project applied a five-year time horizon to provide near-term solutions to the prospective decision makers and take maximum advantage of commercial off-the-shelf (COTS) solutions and emphasize new Concepts of Operations (CONOPS) for existing systems. Results provided insight into requirements for interagency interactions in support of Maritime Security and demonstrated the criticality of timely and accurate intelligence in support of counterterror operations.This report was prepared for the Office of the Assistant Secretary of Defense for Homeland DefenseApproved for public release; distribution is unlimited

Reactivation of ancestral strains of HIV-1 in the gp120 V3 env region in patients failing antiretroviral therapy and subjected to structured treatment interruption

We analyzed gp120V3 HIV-1 env region genetic diversity of 27 patients failing antiretrovirals and subjected to 12-week structured treatment interruption (STI). Based on heteroduplex mobility assays, eight patients presented low pre- and post-STI genetic diversity (G1); five presented high pre-STI but low post-STI diversity (G2); five presented low pre-STI and high post-STI diversity (G3); and nine, high pre- and post-STI diversity (G4). One patient from G1, two from G2 and two from G3 were subjected to proviral DNA end-point PCR and sequencing. in three patients, the dramatic disturbance caused by STI resulted in ancestral viral progeny activation, which repopulated the cell reservoir. in two patients presenting highly homogeneous sequences and low immune selective pressure (dN/dS ratio < 1), this phenomenon was not observed. the mechanisms involved in viral evolution, in which antiretroviral therapy also applies selective pressure, sometimes affects coreceptor usage of circulating viruses, leading to the suppression of x4 strains. (c) 2006 Published by Elsevier Inc.Universidade Federal de São Paulo, Escola Paulista Med, Lab Retrovirol, BR-04039032 São Paulo, BrazilFundacao Pro Sangue, BR-05403000 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Lab Retrovirol, BR-04039032 São Paulo, BrazilWeb of Scienc