85,229 research outputs found
Digital-twin-based active input refinement for insertion loss estimation and QoT optimization in C and C + L networks
Full text linkQuality of transmission (QoT) prediction is a fundamental function in optical networks. It is typically embedded within a digital twin and used for operational tasks, including service establishment, service rerouting, and (per-channel or per-amplifier) power management to optimize the working point of services and hence to maximize their capacity. Inaccuracy in QoT prediction results in additional, unwanted design margins. A key contributor to QoT inaccuracy is the uncertain knowledge of fiber insertion loss, e.g., the attenuation due to connector losses at the beginning or at the end of each fiber span, as such loss cannot be directly monitored. Indeed, insertion losses drive the choice of the launch power in fiber spans, which in turn drive key physical effects, including the Kerr and stimulated Raman scattering (SRS) effects, which affect services’ QoT. It is thus important to estimate (and detect possibly anomalous) fiber insertion losses at each span. We thereby propose a novel active input refinement (AIR) technique using active probing to estimate insertion losses in C and C
L systems. Here, active probing consists of adjusting amplifier gains span by span to slightly alter SRS. The amount of adjustment must be sufficient to be measurable (such that insertion losses can be inferred from the measures) but small enough to have a negligible impact on running services in a live network. The method is validated by simulations on a European network with 30 optical multiplex sections (OMSs) in C and C
L configurations and by lab experiments on a C-band network, demonstrating that AIR significantly improves insertion loss estimation, network QoT optimization, and QoT prediction compared with other state-of-the-art monitoring techniques. This work underscores the critical role of accurate estimation of QoT inputs in enhancing optical network performance
Superconducting HgBa2CaCu2Oy thin films growth on NdGaO3, SrTiO3, LaAlO3 and Y-ZrO2 substrates
No full textSuperconducting HgBa2CaCu2Oy (Hg-1212) films have been fabricated on (110) NdGaO3, (100) SrTiO3, (100) LaAlO3 and (100) Y-ZrO2 substrates by a two-step process. Good reproducible superconducting properties, zero resistance temperatures (T-c) > 115 K and critical current density (J(c)) > 4000 MA/m(2) at 77 K in zero field, are obtained. X-ray diffraction patterns indicate that the films have an epitaxial structure with the c-axis perpendicular to the surface. Scanning electron microscopy measurements show a layered growth structure with square and octagonal grains on the Hg-1212 film surfaces. (110) NdGaO3 is demonstrated to be a good substrate for growing the Hg-cuprate thin films. A lower superconducting transition temperature is observed in films deposited on Y-ZrO2 substrates, which can be attributed to variations of the microstructure in the films. (C) 1999 Elsevier Science B.V. All rights reserved.Physics, AppliedSCI(E)EI18ARTICLE3-4197-20131
Resistivity and Hall effect in the ab-plane of high TcHgBa2CaCu2O6+y epitaxial films
No full textBy using of high quality HgBa2CaCu2O6+y (Hg-1212) epitaxial films the resistivity and the normal state Hull effect in ab-plane have been studied, These properties indicate that Hg deficient Hg-1212 is an under-doped superconductor. In post annealing experiments we found that Hg carl diffuse our from and into the films at 350 degreesC depending on the Hg vapor pressure. The Hg deficient films show degraded superconductivity. Through annealing them in Hg atmosphere we recovered completely their superconductivity. Using these Hg-1212 films with different cation vacancy contents the relationship between T-C and the Hall coefficient was studied. 1/R-H uas found to have T- linear behavior above a crossover temperature T* and a weakened T-dependence below T*. This interesting behavior may be attributed to a pseudo-gap.Physics, AppliedSCI(E)EICPCI-S(ISTP)
Analytical sun synchronous low-thrust manoeuvres
No full textArticle describes analytical sun synchronous low-thrust manoeuvres
SunSmart? Skin cancer knowledge and preventive behaviour in a British population representative sample
No full textThe incidence of skin cancer has risen rapidly in the UK over the last 20 years, prompting public health organizations to try and raise awareness of the dangers of sun exposure and the need to practice sun-safe behaviour. This study aimed to assess baseline levels of sun-safe knowledge and behaviour in a British population-representative sample, prior to the launch of Cancer Research UK's 'SunSmart' campaign. A face-to-face survey was conducted through the Office for National Statistics as part of their Omnibus survey. In total, 1848 men and women aged 18 and over were interviewed. Knowledge of what to do to reduce skin cancer risk was modest. Two-thirds mentioned avoiding the sun by seeking shade, 50% mentioned covering up and only 43% said to use high factor sunscreen. Practice of sun-safe behaviours was also poor, with only one-third saying they sought shade, covered up or used high factor sunscreen to protect themselves from the sun. Men and those from lower socioeconomic groups were least informed and least likely to report using sun-protective behaviours. Increases in both knowledge and use of appropriate sun-protective behaviours are needed if skin cancer incidence rates are to decrease
A grounded theory of female adolescent behaviour in the sun: comfort matters.
No full textThe aim of the research was to generate a grounded theory to explain the behaviour of young women in the sun. The study sought to explore the sun-related experiences of
young women in order to gain new insights into the influences upon them. The study was qualitative by design and utilised grounded theory method as developed by Glaser.
Twenty female participants, aged 14 to 17 years old were included in the study. They formed six groups. Thirteen interviews were carried out with the groups and six one-to one interviews took place with individuals. All interviews were semi-structured and were based upon the participants' experiences of being in the sun. Data was analysed using the
constant comparative method of data analysis, concordant with Glaserian grounded theory method. Five explanatory categories emerged from the data; Fitting In, Being Myself,
Being Physically Comfortable, Slipping Up and a core category of Being Comfortable. One of the issues that emerged was that some young women believed their social
acceptance depended on their appearance and they conformed to this end. The theory, derived from the categories, proposes that when in the sun, young women direct their
activities toward meeting physical and psychosocial comfort needs. Comfort matters to them because it has implications for their wellbeing. This thesis contributes to the literature about the behaviours of young women in the sun.
By increasing understanding of the factors that influence them, it also adds to the body of knowledge related to the primary prevention of skin cancer with teenage girls in the United Kingdom. The outcome of the research and its contribution to knowledge is a grounded theory, which explains the basis of the behaviours of young women in the sun. It appears that no other study has explored the experiences of UK adolescent females specifically, in
a qualitative way and with the intention of producing a theory to explain them
Phosphorylation status of transcription factor C/EBPα determines cell surface poly-LacNAc branching (I antigen) formation in erythropoiesis and granulopoiesis
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Magnetoresistance and microstructure of the sintered ferrite of the mixture of Fe3O4 and Co-ferrite powder
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