31 research outputs found
Assessing the Nature of the Distribution of Localised States in Bulk GaAsBi.
A comprehensive assessment of the nature of the distribution of sub band-gap energy states in bulk GaAsBi is presented using power and temperature dependent photoluminescence spectroscopy. The observation of a characteristic red-blue-red shift in the peak luminescence energy indicates the presence of short-range alloy disorder in the material. A decrease in the carrier localisation energy demonstrates the strong excitation power dependence of localised state behaviour and is attributed to the filling of energy states furthest from the valence band edge. Analysis of the photoluminescence lineshape at low temperature presents strong evidence for a Gaussian distribution of localised states that extends from the valence band edge. Furthermore, a rate model is employed to understand the non-uniform thermal quenching of the photoluminescence and indicates the presence of two Gaussian-like distributions making up the density of localised states. These components are attributed to the presence of microscopic fluctuations in Bi content, due to short-range alloy disorder across the GaAsBi layer, and the formation of Bi related point defects, resulting from low temperature growth
Deep-level defects in n-type GaAsBi alloys grown by molecular beam epitaxy at low temperature and their influence on optical properties
Deep-level defects in n-type GaAs1-x Bi x having 0 ≤ x ≤ 0.023 grown on GaAs by molecular beam epitaxy at substrate temperature of 378 °C have been injvestigated by deep level transient spectroscopy. The optical properties of the layers have been studied by contactless electroreflectance and photoluminescence. We find that incorporating Bi suppresses the formation of GaAs-like electron traps, thus reducing the total trap concentration in dilute GaAsBi layers by over two orders of magnitude compared to GaAs grown under the same conditions. In order to distinguish between Bi- and host-related traps and to identify their possible origin, we used the GaAsBi band gap diagram to correlate their activation energies in samples with different Bi contents. This approach was recently successfully applied for the identification of electron traps in n-type GaAs1-x N x and assumes that the activation energy of electron traps decreases with the Bi (or N)-related downward shift of the conduction band. On the basis of this diagram and under the support of recent theoretical calculations, at least two Bi-related traps were revealed and associated with Bi pair defects, i.e. (VGa+BiGa)(-/2-) and (AsGa+BiGa)(0/1-). In the present work it is shown that these defects also influence the photoluminescence properties of GaAsBi alloys
Flourishing in subterranean ecosystems: Euro-Mediterranean Plusiocampinae and tachycampoids (Diplura, Campodeidae)
Este artículo contiene 138 páginas, 213 figuras, 14 tablas.Diplura is a group of entognathous hexapods, often considered a sister group to insects. They
play an important role in recycling organic matter in soil and subterranean terrestrial ecosystems. The
Campodeidae is the most diverse family, divided into four subfamilies. The subfamily Plusiocampinae
has a subterranean life-style with many species distributed in the Euro-Mediterranean area. The incertae
sedis tachycampoids (“lignée Tachycampoïde”) is a group within the family Campodeidae that share
with the Plusiocampinae a strong preference for subterranean habitats and several morphological
characters, such as slender body shape, elongated appendages, considerable increment in the number of
antennomeres and cercal articles, and complexity of sensorial structures. The present monograph provides
a taxonomic revision of the subfamily Plusiocampinae and the genera belonging to the tachycampoid
lineage from Europe and the Mediterranean region. It comprises detailed morphological descriptions
and illustrations together with data on the habitats and distributions of 87 species, 10 subspecies and
11 affinis forms. Seven new species are described among those, namely: Plusiocampa (Plusiocampa)
apollo Sendra, Giachino & Vailati sp. nov., P. (P.) chiosensis Sendra & Gasparo sp. nov., P. (P.) dublanskii
Sendra & Turbanov sp. nov., P. (P.) hoffmanni Sendra & Paragamian sp. nov., P. (P.) rhea Sendra
sp. nov., P. (P.) ternovensis Sendra & Borko sp. nov. and P. (Venetocampa) ferrani Sendra & Delić
sp. nov.DS’s field trips were funded by the
Serbian Ministry of Education, Science and Technology (Grant 173038); KP was partially funded
by the HISR project “Conservation of the Cave Fauna of Greece” funded by the MAVA Foundation
and WWF Greece; PMG and DV carried out sampling in Greece using permits from the Ministry of
Environment no. 124085/1362/2015, 135366/373/2016 and 166238/248/2018; IT was funded within
the framework of the state assignment of FASO Russia (themes no. АААА-А18-118012690106-7 and
АААА-А18-118012690105), supported in part by RFBR (project no. 17-54-40017Абх_а); sampling
efforts by AF and colleagues resulted from various projects on the evolution of cave fauna diversity, some
of them funded by the German Research Foundation, DFG (DFG FA 1042/1-1 and DFG BA 2152/14-1);
PMG and DV were partly supported by the program “Research Missions in the Mediterranean Basin”
sponsored by the World Biodiversity Association onlus XLI contribution; ASPSR was supported by
a research grant (15471) from Villum Fonden.Peer reviewe
Serological response and breakthrough infection after COVID-19 vaccination in patients with cirrhosis and post-liver transplant
BACKGROUND: Vaccine hesitancy and lack of access remain major issues in disseminating COVID-19 vaccination to liver patients globally. Factors predicting poor response to vaccination and risk of breakthrough infection are important data to target booster vaccine programs. The primary aim of the current study was to measure humoral responses to 2 doses of COVID-19 vaccine. Secondary aims included the determination of factors predicting breakthrough infection. METHODS: COVID-19 vaccination and Biomarkers in cirrhosis And post-Liver Transplantation is a prospective, multicenter, observational case-control study. Participants were recruited at 4-10 weeks following first and second vaccine doses in cirrhosis [n = 325; 94% messenger RNA (mRNA) and 6% viral vaccine], autoimmune liver disease (AILD) (n = 120; 77% mRNA and 23% viral vaccine), post-liver transplant (LT) (n = 146; 96% mRNA and 3% viral vaccine), and healthy controls (n = 51; 72% mRNA, 24% viral and 4% heterologous combination). Serological end points were measured, and data regarding breakthrough SARS-CoV-2 infection were collected. RESULTS: After adjusting by age, sex, and time of sample collection, anti-Spike IgG levels were the lowest in post-LT patients compared to cirrhosis (p < 0.0001), AILD (p < 0.0001), and control (p = 0.002). Factors predicting reduced responses included older age, Child-Turcotte-Pugh B/C, and elevated IL-6 in cirrhosis; non-mRNA vaccine in AILD; and coronary artery disease, use of mycophenolate and dysregulated B-call activating factor, and lymphotoxin-α levels in LT. Incident infection occurred in 6.6%, 10.6%, 7.4%, and 15.6% of cirrhosis, AILD, post-LT, and control, respectively. The only independent factor predicting infection in cirrhosis was low albumin level. CONCLUSIONS: LT patients present the lowest response to the SARS-CoV-2 vaccine. In cirrhosis, the reduced response is associated with older age, stage of liver disease and systemic inflammation, and breakthrough infection with low albumin level
GaSbBi alloys and heterostructures: fabrication and properties
International audienceDilute bismuth (Bi) III-V alloys have recently attracted great attention, due to their properties of band-gap reduction and spin-orbit splitting. The incorporation of Bi into antimonide based III-V semiconductors is very attractive for the development of new optoelectronic devices working in the mid-infrared range (2-5 µm). However, due to its large size, Bi does not readily incorporate into III-V alloys and the epitaxy of III-V dilute bismides is thus very challenging. This book chapter presents the most recent developments in the epitaxy and characterization of GaSbBi alloys and heterostructures
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Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks
无线传感器网络,作为全球未来十大技术之一,集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术,可实时感知、采集、处理、传输网络分布区域内的各种信息数据,在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议,并针对大规模的无线传感器网络设计了一种树状路由协议,它根据节点地址信息来形成路由,从而简化了复杂繁冗的路由表查找和维护,节省了不必要的开销,提高了路由效率,实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR(AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位:工学硕士院系专业:信息科学与技术学院通信工程系_通信与信息系统学号:2332007115216
Context-aware application for mobile banking
The field of mobile applications is rapidly evolving. The reason for this lies in the development of smartphones and in the beginning of their wider usage. The development of mobile applications is therefore spreading into different fields. One of them is mobile banking.
Mobile banking represents new possibilities in the banking sector. It enables banking services that are independent from time and location and, with transition to smartphones, it also enables the usage of advantages of mobile operating systems. The Slovenian banking sector lags behind mobile banking development of the modern world. Slovenian banks merely offer internet banking services that are adapted to mobile phones and do not use advanced features of mobile operating systems. Based on the given information we decided to develop a mobile banking application that is adapted to specific needs of the modern user.
The primary goal of this diploma thesis is the development of a mobile banking application on a BlackBerry platform that offers advanced graphical user interface, different input methods, runs on any mobile device that uses BlackBerry 5.0.0. operating system and that uses context awareness.
The result of our work represents a mobile banking application that offers the performance of banking services on BlackBerry smartphones. The mobile application provides basic and advanced overview of managed accounts, transaction review, and UPN (universal payment form) payments. Implementation of context awareness expands basic functionalities of the mobile application. The look of graphical user interface depends on the frequency of the usage of buttons, bank accounts and fast payments. It also offers additional functionalities that depend on the current context information needs of the user. These offer a unique user experience.
This diploma thesis describes the mobile banking sector, the development area of mobile banking applications, area of smartphones, context awareness, the development and functionalities of the developed mobile application, development problems and further development possibilities