22 research outputs found
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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
The Compact Linear Collider (CLIC) - 2018 Summary Report
The Compact Linear Collider (CLIC) is a TeV-scale high-luminosity linear collider under development at CERN. Following the CLIC conceptual design published in 2012, this report provides an overview of the CLIC project, its current status, and future developments. It presents the CLIC physics potential and reports on design, technology, and implementation aspects of the accelerator and the detector. CLIC is foreseen to be built and operated in stages, at centre-of-mass energies of 380 GeV, 1.5 TeV and 3 TeV, respectively. CLIC uses a two-beam acceleration scheme, in which 12 GHz accelerating structures are powered via a high-current drive beam. For the first stage, an alternative with X-band klystron powering is also considered. CLIC accelerator optimisation, technical developments and system tests have resulted in an increased energy efficiency (power around 170 MW) for the 380 GeV stage, together with a reduced cost estimate at the level of 6 billion CHF. The detector concept has been refined using improved software tools. Significant progress has been made on detector technology developments for the tracking and calorimetry systems. A wide range of CLIC physics studies has been conducted, both through full detector simulations and parametric studies, together providing a broad overview of the CLIC physics potential. Each of the three energy stages adds cornerstones of the full CLIC physics programme, such as Higgs width and couplings, top-quark properties, Higgs self-coupling, direct searches, and many precision electroweak measurements. The interpretation of the combined results gives crucial and accurate insight into new physics, largely complementary to LHC and HL-LHC. The construction of the first CLIC energy stage could start by 2026. First beams would be available by 2035, marking the beginning of a broad CLIC physics programme spanning 25-30 years
Risk Factors of In-Hospital Mortality in Patients Treated for Pneumonia at a Tertiary Care Centre in Switzerland
Background: Little is known about risk factors upon hospital admission that are associated with in-hospital death of patients hospitalized for bacterial pneumonia. Identifying such factors may help to optimize the treatment and lower the mortality of these patients. Objectives: The aim of the study was to characterize baseline characteristics of patients hospitalized for bacterial pneumonia in Switzerland and to identify risk factors associated with all-cause in-hospital mortality. Methods: Routinely collected electronic health record data of patients discharged from a large Swiss tertiary care hospital between August 2009 and 2017 were analysed. Potential risk factors such as patient demographics, physical examination findings, vital signs, laboratory results, and comorbidities were considered within ±24 h of admission. Univariable and multivariable logistic regression models identified risk factors for in-hospital death. The area under the receiver operating characteristic (ROC) curve was used to compare the identified factors to existing pneumonia scoring systems. Results: Out of 1,781 hospital stays with initial and main diagnosis of bacterial pneumonia, 85 patients (4.85%) died (33.9% female, median age 62.3 years [interquartile range, 52–75]). Age, low systolic blood pressure, underweight, a missing value for body mass index, decreased haemoglobin level, raised C-reactive protein, high urea, high lactate dehydrogenase, concomitant pleural effusion, and cancer were independently associated with in-hospital death. The area under the ROC curve was 0.89 for the multivariable model containing the identified predictors. Conclusions: Our data are consistent with previous trials characterizing patients hospitalized for pneumonia. Additionally, we identified new and independent risk factors associated with in-hospital death among patients treated for bacterial pneumonia. Findings need to be further validated in larger multicentre cohorts
Microstructure and Mechanical Performance of Cu-Sn-Ti-Based Active Braze Alloy Containing In Situ Formed Nano-Sized TiC Particles
A Cu-Sn-Ti-based active brazing filler alloy was in situ reinforced with nanosized TiC particles by adding different amounts of a cellulose nitride-based binder. The TiC particles emanate from a reaction of the Ti within the filler alloy with the carbon from the binder that does not decompose completely during heating. The correlation between the microstructure and mechanical performance was studied. In addition, the effect of different binder amounts on the shear strength and cutting performance of brazed diamond grains was studied in shear tests and single grain cutting tests. The results clearly show that the mechanical performance of the brazed diamond grains can be improved by the formation of TiC particles. This is attributed to particle strengthening of the filler alloy matrix as well as to the decreasing grain size and more homogeneous distribution of the (Cu,Sn)3Ti5 phase with increasing amount of binder
Active vacuum brazing of CNT films to metal substrates for superior electron field emission performance
The joining of macroscopic films of vertically aligned multiwalled carbon nanotubes (CNTs) to
titanium substrates is demonstrated by active vacuum brazing at 820 °C with a Ag–Cu–Ti alloy
and at 880 °C with a Cu–Sn–Ti–Zr alloy. The brazing methodology was elaborated in order to
enable the production of highly electrically and thermally conductive CNT/metal substrate
contacts. The interfacial electrical resistances of the joints were measured to be as low as 0.35 Ω.
The improved interfacial transport properties in the brazed films lead to superior electron fieldemission
properties when compared to the as-grown films. An emission current of 150 μA was
drawn from the brazed nanotubes at an applied electric field of 0.6 V μm−1. The improvement in
electron field-emission is mainly attributed to the reduction of the contact resistance between the
nanotubes and the substrate. The joints have high re-melting temperatures up to the solidus
temperatures of the alloys; far greater than what is achievable with standard solders, thus
expanding the application potential of CNT films to high-current and high-power applications
where substantial frictional or resistive heating is expectedPeer reviewe