In situ assessment of carbon nanotube diameter distribution with photoelectron spectroscopy

7 págs.; 6 figs.; 1 tab. ; PACS numberssd: 73.22.2f, 79.60.Jv, 61.46.1wIn situ UV-photoelectron spectroscopy (He I and He II) was performed on multiwalled carbon nanotubes (CNTs) with clearly differentiated diameter distributions. A significant dependence of valence- and conduction-band characteristics on the mean CNT diameter was observed, which was determined by high-resolution TEM and micro-Raman spectroscopy. The decrease of relative intensity of the π states at -3 eV in the He II experiments, indicative of increasing rehybridization between orbitals, was directly correlated with decreasing mean diameters. Furthermore, a progressive broadening of the unoccupied σ* band at 7.6 eV was found in the He I spectra. © 2005 The American Physical Society.J.W.S. is grateful to the Centre Interdisciplinaire de Microscopie Electronique sCIMEd at the Ecole Polytechnique Fédérale de Lausanne sEPFLd for access to TEM and technical support. We also thank the National Centre of Competence in Research for Nanosciences NCCRd and the Swiss National Foundation for financial support.Peer Reviewe

The validation of the association between gene polymorphisms and the cytogenetic abnormalities frequency in the cohort of radiation facility employees

The results from the research into the association between polymorphisms of genes-candidates for individual radiosensitivity and the frequency and spectrum of cytogenetic abnormalities are analyzed. These polymorphisms have been previously identified in our microarray studies using “Cancer_SNP_Panel GT-17- 211” (“Illumina”, USA) in 2013. The study was conducted among Siberian Group of Chemical Enterprises healthy employees (n = 158) exposed to professional irradiation in a dose range of 100-300 mSv. We have found that 16 SNPs are associated with the frequency of dicentric and ring (the radiation exposure markers). We have found that 9 SNPs are confirmed to be associated with the frequency of dicentric (INSR rs1051690, TNKS rs33945943, CYP24A1 rs751087, GSK3B rs4624596, GSK3B rs4688046, GSK3B rs10934500, GSK3B rs1574154, GSK3B rs2873950, VCAM1 rs2392221) and 14 SNPs are confirmed to be associated with the frequency of ring (ESR1 rs488133, PIN1 rs889162, PIN1 rs2233679, CYP2С19 rs4986894, CYP24A1 rs751087, APAF1 rs2288729, MPDU1 rs4227, GSK3B rs4624596, GSK3B rs4688046, GSK3B rs10934500, GSK3B rs10934503, GSK3B rs1574154, GSK3B rs2873950, VCAM1 rs2392221)

First mirror tests for ITER: influence of material choice on the deposition/ erosion mechanisms affecting optical reflectivity

Almost all optical diagnostics systems on ITER will be based on in-vessel metallic first mirrors. The possible deterioration of their surface reflectivity as a result of erosion by charge-exchange neutrals and re-deposition of material eroded from the plasma-facing components represents a serious concern for the reliability of spectroscopic and laser signals. A concerted effort within the tokamak community has been initiated to characterize these effects and seek mitigation methods. To date, the different damaging effects (erosion and deposition) have always been considered independently, neglecting any role that may be played by the substrate. In this contribution, we attempt to assess the influence of substrate material using different approaches: laboratory simulation experiments, mirror exposures in the divertor region of the TCV tokamak and numerical simulations using the Monte-Carlo code TRIDYN. Our results have potentially important implications for the choice of ITER first mirror materials

Solar heat gains through train windows: a non-negligible contribution to the energy balance

The sector of transportation accounts for about one third of the total energy consumption in Switzerland. A monitoring campaign of the energy consumption of a regional train revealed the critical energy-consuming systems. Heating, cooling and ventilation were identified as major consumers. Windows are a source of non-controlled heat transfer. In summer, it may result in overheating leading to larger cooling loads while in winter, it is an important source of thermal losses. Selective double glazing and solar protection coatings can reduce these effects. Angular-dependent optical properties of a selective double glazing have been measured, and the solar heat gain coefficient (g value) was determined. An estimation of the solar gains received by a panoramic waggon was performed using the monitored solar irradiation and the measured properties of the glazing. These data were compared to the heating and cooling energy consumption monitored in this waggon. Solar gains were found to be in the same order of magnitude that the heating energy during some sunny days. They were also compared to the estimated thermal losses through the glazing and the entire envelope. These results show that the solar gains play a non-negligible role in the energy balance of the waggon. Furthermore, thermal simulations were performed to evaluate the solar gains in different conditions. It showed that 7 to 13% of energy can be saved using the glazing adapted to the climatic conditions. In addition, improving the thermal insulation of the train envelope or equipping the train with an efficient heat recovery system can lead to significant energy savings

Non-Visual Effects of Light on Melatonin, Alertness and Cognitive Performance: Can Blue-Enriched Light Keep Us Alert?

Light exposure can cascade numerous effects on the human circadian process via the non-imaging forming system, whose spectral relevance is highest in the short-wavelength range. Here we investigated if commercially available compact fluorescent lamps with different colour temperatures can impact on alertness and cognitive performance

Accelerated CMR using zonal, parallel and prior knowledge driven imaging methods

Accelerated imaging is highly relevant for many CMR applications as competing constraints with respect to spatiotemporal resolution and tolerable scan times are frequently posed. Three approaches, all involving data undersampling to increase scan efficiencies, are discussed in this review. Zonal imaging can be considered a niche but nevertheless has found application in coronary imaging and CMR flow measurements. Current work on parallel-transmit systems is expected to revive the interest in zonal imaging techniques. The second and main approach to speeding up CMR sequences has been parallel imaging. A wide range of CMR applications has benefited from parallel imaging with reduction factors of two to three routinely applied for functional assessment, perfusion, viability and coronary imaging. Large coil arrays, as are becoming increasingly available, are expected to support reduction factors greater than three to four in particular in combination with 3D imaging protocols. Despite these prospects, theoretical work has indicated fundamental limits of coil encoding at clinically available magnetic field strengths. In that respect, alternative approaches exploiting prior knowledge about the object being imaged as such or jointly with parallel imaging have attracted considerable attention. Five to eight-fold scan accelerations in cine and dynamic CMR applications have been reported and image quality has been found to be favorable relative to using parallel imaging alone