Dual-Color Antenna-Coupled LEKID for Next-Generation Multi-chroic CMB Focal Planes

We present an antenna-coupled Kinetic Inductance Detector for millimeter wave astronomy. Next-generation telescopes for observing the cosmic microwave background are demanding in terms of number of detectors and focal plane area filling efficiency. Moreover, foreground reduction in B-Mode polarimetry requires sky observation with multiple frequency bands. In this context, KIDs are a promising technology because of their large multiplexing rate, while antenna coupling can provide multi-band and dual-polarization solutions in compact design. We have developed polarization-sensitive dual-band pixel at 140 and 160 GHz with a bandwidth of almost 8% for each sub-band. The design involves a microstrip-excited slot antenna and two open-stub band-pass filters to direct the signal toward two resonators. These are lumped elements capacitively coupled to the antenna and include an aluminum strip as absorber. The architecture proposed is particularly simple to fabricate, via-less and only involves two metallization levels. The transition does not require any dielectric deposition above the resonator, thus preventing limitations from any source of noise due to a non-monocrystalline substrate. Furthermore, the same coupling technique can be applied to many types of microstrip-excited antennas, which allow to accommodate band-pass filters.     

Large deformation mechanical behavior of flexible nanofiber filled polymer nanocomposites

In the present work, the large deformation behavior of high aspect ratio flexible nanofiber reinforced polymer composites is investigated. Simple or successive tensile tests are performed at room temperature, i.e. in the rubbery state. By studying two different types of fibers, namely cellulose nanofibrils and carbon nanotubes, with two processing routes, the role of entanglements and of interactions existing between fibers—within the nanofiber network that can be formed in the material—on the composite properties is highlighted. For cellulosic nanofillers, strong hydrogen bonds between fibers lead to a spectacular reinforcement effect combined with a decrease of the composite ultimate strain and an irreversible damage of composite properties after first deformation (rigid network). When such strong interactions between fillers are limited (soft entangled network or simple contacts between non-entangled fibers) the resulted reinforcement is less important and no decrease of the deformation at break is observed. For carbon nanotube fillers, the evolution of the filler network during tensile test is finally highlighted by in situ electrical measurements.     

Fabrication and characterization of annular thickness mode piezoelectric micro ultrasonic transducers

Micromachining techniques, in combination with low temperature ceramic composite sol-gel processing, have been used to fabricate annular array thickness-mode piezoelectric micro ultrasonic transducers (Tm-pMUTs). The processing techniques of low temperature (710 degrees C) composite sol-gel ceramic (sol + ceramic powder) deposition and wet etching were used to deposit and structure 27-microm thick lead zirconate titanate (PZT) films on silicon substrates to produce annular array Tm-pMUTs. Using these techniques, high quality PZT materials with near bulk permittivity have been obtained. The Tm-pMUT devices were shown to resonate at approximately 60 MHz in air and 50 MHz in water. From resonance measurements k(t) values ranging between 0.2 and 0.47 have been calculated and shown to depend on the level of porosity within the film. Lower values of kt were observed for films with higher levels of porosity, which was attributed to the relative decrease in the effective piezoelectric coefficient epsilon(33) with respect to stiffness and permittivity as a function of increasing porosity. This paper presents the successful micro-fabrication of a Tm-pMUT device and discusses the optimization of the poling conditions and effect of PZT microstructure on the coupling coefficient k(t). Pulse echo measurements in water, showing a -6 dB center frequency of 53 MHz and 47% -6 dB bandwidth, using a target 15 mm away from the transducer, have been included to demonstrate successful operation of the device. Full analysis of these results will be conducted in later publications.     

Preparation of 5‐Membered Rings via Radical Addition‐ Translocation‐Cyclization (RATC) Processes Mediated by Diethyl Thiophosphites

A practical method for the formation of thiophosphonates bearing functionalized monocyclic, fused bicyclic and spirocyclic residues is presented. The procedure requires the easily available terminal alkynes as starting materials as well as commercially and readily available reagents such as diethyl thiophosphite. The experimental procedure consists of a one‐pot process without any slow addition of one of the reagents.     

Optical modeling of organic solar cells based on CuPc and C60

We have investigated the influence of the poly(3,4-ethylenedioxythiophene)-blend-poly(styrene-sulfonate) (PEDOT:PSS) layer on the short-circuit current density (J(sc)) of single planar heterojunction organic solar cells based on a copper phthalocyanine (CuPc)-buckminsterfullerene (C(60)) active layer. Complete optical and electrical modeling of the cell has been performed taking into account optical interferences and exciton diffusion. Comparison of experimental and simulated external quantum efficiency has allowed us to estimate the exciton diffusion length to be 37 nm for the CuPc and 19 nm for the C(60). The dependence of short-circuit current densities versus the thickness of the PEDOT:PSS layer is analyzed and compared with experimental data. It is found that the variation in short-circuit current densities could be explained by optical interferences.     

Novozym 435-catalyzed synthesis of polyetheramides from amino-esters,or diesters and diamines built on ethylene- and diethylene- glycol moieties

The optimization of CAL-B-promoted (Novozym 435) A/B and AA/BB type polymerizations leading to polyetheramides, from amino ethylesters or diethyl esters and diamines based on ethylene- or diethylene-glycol moieties, is disclosed herein. From these preliminary experiments it became obvious that it is of prime importance: to avoid the presence of water by carefully drying the enzyme prior to use; to eliminate ethanol from the reaction medium, by working under reduced pressure in order to drive the amidation reaction forward; to select an appropriate high boiling solvent, the best choice being diphenyl ether. Under such experimental conditions, polyetheramides were obtained in 70–80% yield with an average degree of polymerization (DPn) up to 17.     

Leachability and termite resistance of wood treated with a new preservative: ammonium borate oleate

Synthesis of a new chemical compound combining water-repellence of oleic acid and biocidal effect of boric acid linked by ammonia have been followed and validated by fourier transformed infra red (FTIR). This compound named ammonium borate oleate (ABO) has then been studied as a wood preservative. Different molar ratios of oleic acid have been involved in the synthesis of ABO and leachability of those mixes from wood observed according to Japanese industrial standard. The formulation one mole of boric acid and one of ammonia (1:1:4) for four moles of oleic acid has shown the best efficiency compared to formulations 1:1:1, 1:1:2 and 1:1:3 with about 52% of boron remaining after weathering when other formulations retained respectively 10%, 29% and 46% of boron in the case of an impregnation of Cryptomeria japonica. Seven solutions of 1:1:4 ABO in ethanol of different concentrations were then produced and sapwood blocks of C. japonica and Fagus crenata were impregnated. A toxicity threshold of around 2.0 kg/m³ for both species was determined in a termite resistance test to Coptotermes formosanus indicating the positive effect of combining water repellent and biocide. Termite mortality recording and microscopic observations complete this study indicating that the action mechanism of ABO is providing a water resistant inner coating.     

Design for mass customization: Product variety vs. process variety

Mass customization (MC) has become a reality and cannot be neglected as one of the leading strategies in satisfying customers and assuring companies survival in today's markets. MC can be offered either via product variability or process variability. How this is achieved using both approaches is the main core of this article. After an overview of related works, the influence of design variability on the overall generated value of the product is studied via a metric approach. A case study of the shoe industry is also presented, based on the experience of a European project called Dorothy.