143 research outputs found

    Proton Drivers for Neutrino Factories: The CERN Approach

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    The paper describes the CERN approach for a proton driver for a Neutrino Factory. Two main layouts are presented: the so-called CERN Reference Scenario, based on a 2.2 GeV linac and an alternative one, based on a 30 GeV synchrotron. Both produce bunches of 1 ns (r.m.s.) and a beam power of 4 MW

    Surgery for anomalous aortic origin of coronary arteries : a multicentre study from the European Congenital Heart Surgeons Association

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    OBJECTIVES: We sought to describe early and late outcomes in a large surgical series of patients with anomalous aortic origin of coronary arteries. METHODS: We performed a retrospective multicentre study including surgical patients with anomalous aortic origin of coronary arteries since 1991. Patients with isolated high coronary takeoff and associated major congenital heart disease were excluded. RESULTS: We collected 156 surgical patients (median age 39.5 years, interquartile range 15-53) affected by anomalous right (67.9%), anomalous left (22.4%) and other anatomical abnormalities (9.6%). An interarterial course occurred in 86.5%, an intramural course in 62.8% and symptoms in 85.9%. The operations included coronary unroofing (56.4%), reimplantation (19.2%), coronary bypass graft (15.4%) and other (9.0%). Two patients with preoperative cardiac failure died postoperatively (1.3%). All survivors were discharged home in good clinical condition. At a median follow-up of 2 years (interquartile range 1-5, 88.5% complete), there were 3 deaths (2.2%), 9 reinterventions in 8 patients (5 interventional, 3 surgical); 91.2% are in New York Heart Association functional class <= II, but symptoms persisted in 14.2%; 48.1% of them returned to sport activity. On Kaplan-Meier analysis, event-free survival at follow-up was 74.6%. Morbidity was not significantly different among age classes, anatomical variants and types of surgical procedures. Furthermore, return to sport activity was significantly higher in younger patients who participated in sports preoperatively. CONCLUSIONS: Surgical repair of anomalous aortic origin of coronary arteries is effective and has few complications. Unroofing and coronary reimplantation are safe and are the most common procedures. The occurrence of late adverse events is not negligible, and long-term surveillance is mandatory. Most young athletes can return to an unrestrained lifestyle

    A Study of Diffusion Strategies of Innovation Products with Network Externalities

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    网络外部性是网络经济的一个本质特征,在网络外部性条件下,市场竞争与消费者行为都会表现出不同的特点。本文研究了网络外部性条件下,如何通过采取一定的市场扩散策略来加快创新产品扩散的问题。本文的分析研究表明,网络外部性的存在加强了制定针对网络外部性创新产品市场扩散策略的必要性。由于网络外部性的存在对市场竞争和消费者行为都产生了一定的影响,在此情况之下,用户基础对消费决策具有极大影响,此时,一般经济条件下的市场先发优势和产品相对优势对企业竞争力的促进作用受到了一定的削弱,因此,本文提出从市场定位到免费赠样等一系列针对网络外部性创新产品的市场扩散策略。本文分析表明,在网络外部性条件下,创新产品首先应将市...The essence of network economy is network externalities, which make the competition among companies and consumer manners present some new characteristics. This paper mainly discuss how to quicken the diffusion of innovation products by making appropriate diffusion strategies. This paper has proved that network externalities have strengthened the necessity of making diffusion strategies for innovat...学位:工学硕士院系专业:管理学院管理科学系_系统工程学号:2005130125

    The effect of hot days on occupational heat stress in the manufacturing industry: implications for workers' well-being and productivity

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    Climate change is expected to exacerbate heat stress at the workplace in temperate regions, such as Slovenia. It is therefore of paramount importance to study present and future summer heat conditions and analyze the impact of heat on workers. A set of climate indices based on summer mean (Tmean) and maximum (Tmax) air temperatures, such as the number of hot days (HD: Tmax above 30 °C), and Wet Bulb Globe Temperature (WBGT) were used to account for heat conditions in Slovenia at six locations in the period 1981–2010. Observed trends (1961–2011) of Tmean and Tmax in July were positive, being larger in the eastern part of the country. Climate change projections showed an increase up to 4.5 °C for mean temperature and 35 days for HD by the end of the twenty-first century under the high emission scenario. The increase in WBGT was smaller, although sufficiently high to increase the frequency of days with a high risk of heat stress up to an average of a third of the summer days. A case study performed at a Slovenian automobile parts manufacturing plant revealed non-optimal working conditions during summer 2016 (WBGT mainly between 20 and 25 °C). A survey conducted on 400 workers revealed that 96% perceived the temperature conditions as unsuitable, and 56% experienced headaches and fatigue. Given these conditions and climate change projections, the escalating problem of heat is worrisome. The European Commission initiated a program of research within the Horizon 2020 program to develop a heat warning system for European workers and employers, which will incorporate case-specific solutions to mitigate heat stress.The work was supported by the European Union Horizon 2020 Research and Innovation Action (Project number 668786: HEATSHIELD)

    Experimental investigation of random noise-induced beam degradation in high-intensity accelerators using a linear Paul trap

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    A random noise-induced beam degradation that could affect intense beam transport over long propagation distances has been experimentally investigated by making use of the transverse beam dynamics equivalence between an alternating-gradient focusing system and a linear Paul trap system. For the present study, machine imperfections in the quadrupole focusing lattice are considered, which are emulated by adding small random noise on the voltage waveform of the quadrupole electrodes in the Paul trap. It is observed that externally driven noise continuously increases the rms radius, transverse emittance, and nonthermal tail of the trapped charge bunch almost linearly with the duration of the noise. The combined effects of collective modes and colored noise are also investigated and compared with numerical simulationsclose3
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