Highly efficient multilayer organic pure-blue-light emitting diodes with substituted carbazoles compounds in the emitting layer

Bright blue organic light-emitting diodes (OLEDs) based on 1,4,5,8,N-pentamethylcarbazole (PMC) and on dimer of N-ethylcarbazole (N,N'-diethyl-3,3'-bicarbazyl) (DEC) as emitting layers or as dopants in a 4,4'-bis(2,2'-diphenylvinyl)-1,1'-biphenyl (DPVBi) matrix are described. Pure blue-light with the C.I.E. coordinates x = 0.153 y = 0.100, electroluminescence efficiency \eta_{EL} of 0.4 cd/A, external quantum efficiency \eta_{ext.} of 0.6% and luminance L of 236 cd/m2 (at 60 mA/cm2) were obtained with PMC as an emitter and the 2,9-dimethyl-4,7-diphenyl-1,10-phenantroline (BCP) as a hole-blocking material in five-layer emitting devices. The highest efficiencies \eta_{EL.} of 4.7 cd/A, and \eta_{ext} = 3.3% were obtained with a four-layer structure and a DPVBi DEC-doped active layer (CIE coordinates x = 0.158, y=0.169, \lambda_{peak} = 456 nm). The \eta_{ext.} value is one the highest reported at this wavelength for blue OLEDs and is related to an internal quantum efficiency up to 20%

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Status of the Micromegas semi-DHCAL

The activities towards the fabrication and test of a 1 m3 semi-digital hadronic calorime- ter are reviewed. The prototype sampling planes would consist of 1 m2 Micromegas chambers with 1 cm2 granularity and embedded 2 bits readout suitable for PFA calorime- try at an ILC detector. The design of the 1 m2 chamber is presented first, followed by an overview of the basic performance of small prototypes. The basic units composing the 1 m2 chamber are 32 \times 48 cm2 boards with integrated electronics and a micro-mesh. Results of character- ization tests of such boards are shown. Micromegas as a proportional detector is well suited for semi-digital hadronic calorimetry. In order to quantify the gain in perfor- mance when using one or more thresholds, simulation studies are being carried out, some of which will be reported in this contribution

Test in a beam of large-area Micromegas chambers for sampling calorimetry

Application of Micromegas for sampling calorimetry puts specific constraints on the design and performance of this gaseous detector. In particular, uniform and linear response, low noise and stability against high ionisation density deposits are prerequisites to achieving good energy resolution. A Micromegas-based hadronic calorimeter was proposed for an application at a future linear collider experiment and three technologically advanced prototypes of 1$\times$1 m$^{2}$ were constructed. Their merits relative to the above-mentioned criteria are discussed on the basis of measurements performed at the CERN SPS test-beam facility

The Olfactory Threshold of Rotundone in Brandy is Ten-fold Higher than in Wine and does not Increase with the Complexity of the Matrix

Rotundone is the only known aroma compound imparting a peppery aroma to wine. Its presence hasrecently been documented in spirits, notably those aged in oak barrels. However, the sensory contributionof rotundone in such alcoholic beverages remains hard to predict, given their high ethanol level. The aimof this study was to estimate olfactory thresholds for rotundone in brandy using three different matrices.Rotundone concentrations in the unspiked samples were 50 ng/L for wine distillate and 135 ng/L for brandy,demonstrating for the first time the presence of rotundone in such spirits and a possible endogenous origin.The olfactory detection threshold was estimated at 103 ng/L in 40% (v/v) ethanol solution, while differencethresholds were 171 ng/L and 189 ng/L in fresh wine distillate and young French brandy, respectively, bothstandardised at 40% (v/v). These thresholds were 10-fold higher than in wines and did not significantlydiffer according to the complexity of the matrix. Our results, which are still preliminary and would deserveto be validated with a larger number of samples and using a higher number of panellists, open new fieldsof investigation for a deeper exploration of the concentration range of rotundone in brandies, particularlythose that underwent a longer ageing period in barrels

MICROMEGAS chambers for hadronic calorimetry at a future linear collider

Prototypes of MICROMEGAS chambers, using bulk technology and analog readout, with 1x1cm2 readout segmentation have been built and tested. Measurements in Ar/iC4H10 (95/5) and Ar/CO2 (80/20) are reported. The dependency of the prototypes gas gain versus pressure, gas temperature and amplification gap thickness variations has been measured with an 55Fe source and a method for temperature and pressure correction of data is presented. A stack of four chambers has been tested in 200GeV/c and 7GeV/c muon and pion beams respectively. Measurements of response uniformity, detection efficiency and hit multiplicity are reported. A bulk MICROMEGAS prototype with embedded digital readout electronics has been assembled and tested. The chamber layout and first results are presented

Doped and non-doped organic light-emitting diodes based on a yellow carbazole emitter into a blue-emitting matrix

A new carbazole derivative with a 3,3'-bicarbazyl core 6,6'-substituted by dicyanovinylene groups (6,6'-bis(1-(2,2'-dicyano)vinyl)-N,N'-dioctyl-3,3'-bicarbazyl; named (OcCz2CN)2, was synthesized by carbonyl-methylene Knovenagel condensation, characterized and used as a component of multilayer organic light-emitting diodes (OLEDs). Due to its -donor-acceptor type structure, (OcCz2CN)2 was found to emit a yellow light at max=590 nm (with the CIE coordinates x=0.51; y = 0.47) and was used either as a dopant or as an ultra-thin layer in a blue-emitting matrix of 4,4'-bis(2,2'-diphenylvinyl)-1,1'-biphenyl (DPVBi). DPVBi (OcCz2CN)2-doped structure exhibited, at doping ratio of 1.5 weight %, a yellowish-green light with the CIE coordinates (x = 0.31; y = 0.51), an electroluminescence efficiency EL=1.3 cd/A, an external quantum efficiency ext= 0.4 % and a luminance L= 127 cd/m2 (at 10 mA/cm2) whereas for non-doped devices utilizing the carbazolic fluorophore as a thin neat layer, a warm white with CIE coordinates (x = 0.40; y= 0.43), EL= 2.0 cd/A, ext= 0.7 %, L = 197 cd/m2 (at 10 mA/cm2) and a color rendering index (CRI) of 74, were obtained. Electroluminescence performances of both the doped and non-doped devices were compared with those obtained with 5,6,11,12-tetraphenylnaphtacene (rubrene) taken as a reference of highly efficient yellow emitter

Modelling of simple cases in view of active stabilisation for a future linear collider

Final focus magnet stabilisation is an important issue when working with nanometre size beams. The present study focuses on mechanical stabilisation. As a first step, the case of a 1m free-fixed aluminium beam placed on a table with active stabilisation has been studied. This work describes three aspects, namely, sensors and actuators to measure and compensate ground motion, mechanical simulations and a feedback loop. Measurements done with low frequency velocity sensors (down to 0.1Hz) in our Annecy lab during office hours show that the displacement RMS on the active table is 1nm at 4Hz compared to 10nm without active stabilisation. Simulations of the dynamic response of the beam have been compared to measurements done with accelerometers placed on the clamping and on the free end of the aluminium beam. The results are in good agreement. We are therefore able to predict by simulation the response of a structure subjected to an external excitation. A first sketch of a feedback loop to compensate specific vibrations has also been developed and allows the simultaneous elimination of several resonance peaks on a reduced-size mock-up. This algorithm will be applied to stabilise a larger mock-up, leading to more realistic experimental conditions. In future tests, the active table will globally stabilise in a range of frequencies from 0.5Hz to 50Hz whereas the feedback loop will compensate single strong resonances

Return to sport and re-tears after anterior cruciate ligament reconstruction in children and adolescents

BACKGROUND: The primary objective of this study was to determine the time to and level of return to sports after anterior cruciate ligament (ACL) reconstruction in children and adolescents. The secondary objectives were to evaluate the risk of early ACL re-tear after return to sports and the risk of ACL tear in the contralateral knee. HYPOTHESIS: The time to return to sports in young patients is considerably longer than in adults. METHODS: A prospective multicentre study was conducted at 12 centres specialised in knee ligament surgery, in children and adolescents younger than 18 years, between 1 January 2015 and 31 October 2015. The patients were divided into a paediatric group with open physes and a skeletally mature group with closed physes. We recorded the time to return to sport, the type of sport resumed, and the occurrence of early re-tears on the same side. A poor outcome was defined as a re-tear or an objective IKDC score of C or D. A contralateral ACL tear was not considered a poor outcome. RESULTS: Of 278 included patients, 100 had open physes and 178 closed physes. In the open physes group, return to running occurred after 10.4±4.7 months, return to pivoting/contact sport training after 13.1±3.9 months, and return to pivoting/contact sport competitions after 13.8±3.8 months. Of the 100 patients, 80% returned to the same sport and 63.5% to pivoting/contact sport competitions. Re-tears occurred in 9% of patients, after 11.8±4.1 months, and contralateral tears in 6% of patients, after 17.2±4.4 months. In all, 19.4% of patients had a poor outcome, including 10.4% with an IKDC score of C or D and 9% with re-tears. In the group with closed physes, return to running occurred after 8.8±5.1 months, return to pivoting/contact sport training after 11.7±4.7 months, and return to pivoting/contact sport competitions after 12.3±4.2 months. Of the 178 patients, 76.9% returned to the same sport and 55.6% to pivoting/contact sport competitions. The re-tear rate was only 2.8% and the contralateral tear rate 5%. In all, 14.7% of patients had poor outcome, including 11.9% with an IKDC score of C or D and 2.8% with re-tears. No risk factors for re-tears were identified; the quadruple-bundle semitendinosus technique showed a non-significant association with re-tears. CONCLUSION: In young children, the return to sport time after ACL reconstruction is considerably longer than 1 year and the return to competitions occurs later and is more difficult. The results of this study indicate that reservations are in order when informing the family about return to sports prospects after ACL reconstruction. The return to pivoting/contact sport competitions should not be allowed until 14 months after surgery in young skeletally immature patients, and the risk of re-injury is high within the first 2 years. LEVEL OF EVIDENCE: IV, retrospective study

Resistive micromegas for sampling calorimetry

MicromegasInternational audienceMicromegas is an attractive option for a gaseous sampling calorimeter. It delivers proportional and fast signals, achieves high efficiency to minimum ionising particles with a compact design and shows well-uniform performance over meter-square areas. The current R&D focuses on large- size spark-protected Micromegas with integrated front-end electronics. It targets an application at future linear colliders (LC) and possible upgrades of LHC experiments for the running at high luminosity. In the later case, occasional sparking should be suppressed to avoid dead-time and technical solutions using resistive coatings are investigated. Small prototypes of resistive and non-resistive Micromegas were constructed and tested in a beam at DESY. Results are reported with emphasis on the impact of the resistive layer on the detector performance