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  • Publication
    Accès libre
    0.35 μm 22μW Multiphase Programmable Clock Generator for Circular Memory SC FIR Filter For Wireless Sensor Applications
    (2006-03-06)
    Dlugosz, Rafal Tomasz
    ;
    Iniewski, K.
    ;
    Talaśka, T.
    The paper presents the programmable multiphase clock generator for switched-capacitor finite impulse response (SC FIR) circular memory filters. The proposed programmable clock circuit enables easy division of such kind of filters into different orders smaller sections, which when connected in series, lead to increase in filter efficiency: reduction of chip area, power dissipation, and rising up of the speed. The proposed clock generator enables adjustment of the impulses width, that simplifies design process and leads to structure, which is more robust to process variation. The clock circuit realized in CMOS 0.35μm technology, dissipates 22 μW from 2 V power supply.
  • Publication
    Métadonnées seulement
    1,1'-Dimethyl-2,2'-biimidazole
    (1999)
    Therrien, Bruno 
    ;
    Beauchamp, Andre L.
    Crystals of the title compd. are monoclinic, space group P21/n, with a 6.6760(10), b 5.5670(9), c 11.471(3) Å, ? 103.88(4)°; Z = 2, dc = 1.302; R = 0.036, Rw(F2) = 0.084 for 779 reflections,. The two rings are approx. coplanar. The mol. lies on a crystallog. inversion center and it adopts the anti conformation keeping the Me groups apart. [on SciFinder(R)]
  • Publication
    Accès libre
    1,1′-Ferrocene dicarboxylic acid pyridin-4-yl ester: A new bidentate ligand in arene ruthenium chemistry
    (2007)
    Auzias, Mathieu
    ;
    Therrien, Bruno 
    ;
    Süss-Fink, Georg 
    1,1′-Ferrocene dicarboxylic acid pyridin-4-yl ester (1) is prepared from 1,1′-ferrocene dicarbonyl chloride and 4-hydroxypyridine. This new bidentate ferrocenoyl ligand reacts with the monocationic complex [(η6-p-cymene)2Ru2 (μ-OH)3]+ to give the dicationic complex [(η6-p-cymene)2Ru2(μ-OH)2(1,1′- (NC5H4–OOC)2–Fc)]2+ (2) (Fc: C5H4–Fe–C5H4), isolated as a tetrafluoroborate salt. The single-crystal X-ray structure analysis of [2][BF4] 2 reveals the ferrocenoyl pyridine ligand 1 to act as μ2-η2 chelating ligand in the dinuclear complex, having replaced a μ2-η1-hydroxo ligand.
  • Publication
    Accès libre
    1,2-Bis-N-[2’-(diphenylphosphanyl)benzoyl]diaminobenzene, a New Chelating Ligand with Versatile Coordination Properties
    (2003)
    Burger, Sylvain
    ;
    Therrien, Bruno 
    ;
    Süss-Fink, Georg 
    1,2-Bis-N-[2’-(diphenylphosphanyl)benzoyl]diaminobenzene (dppbH; 1) was prepared by peptidic coupling and shown to exist, in the solid state, in the form of hydrogen-bonded dimers by single-crystal X-ray structure analysis. As expected, 1 reacts with [MCl2 (cod)] (M = Pd, Pt; cod = cyclooctadiene) to form square-planar complexes. However, in the case of palladium [PdCl2 (dppbH)] (2) is obtained, while in the case of platinum [Pt(dppb)] (3) is formed. Thus, the nature of the metal induces a completely different coordination mode: In 2, the dppbH ligand only coordinates through the two phosphorus atoms, while in 3 a dppb ligand, formed by deprotonation of the two amino functions in dppbH, coordinates through the two phosphorus atoms and through the two nitrogen atoms. The single-crystal X-ray analyses of the two square-planar complexes reveal 2 to contain the two phosphorus atoms in a trans coordination mode and 3 to contain the two phosphorus atoms in a cis coordination mode.
  • Publication
    Métadonnées seulement
  • Publication
    Accès libre
    1,3-Butadienyl-thiocyanate in der Diels-Alder-Reaktion mit anschliessender [3,3]-sigmatroper Umlagerung
    (1986)
    Huber, Stefan
    ;
    Stamouli, Peristera
    ;
    Jenny, Titus
    ;
    Neier, Reinhard 
    (E)- and (Z)-1,3-Butadienyl thiocyanates 3, 4, and 12-15 have been synthesized selectively. Their use as dienes for Diels-Alder reactions followed by a [3,3]-sigmatropic shift to obtain an isomeric isothiocyanate has been studied. The butadienyl thiocyanates are, unfortunately, not very reactive in Diels-Alder reactions. This disadvantage can be overcome, if a trapping reaction with EtOH is added to the two-step sequence. This sequence allows to get good yields of the O-ethyl thiocarbamates 18-23, even if the first two reactions have not favorable equilibrium constants.
  • Publication
    Métadonnées seulement
    1,3-Disubstituted ferrocene-containing thermotropic liquid crystals of form (?5-C5H5)Fe[(?5-C5H3)-1,3-(CO2C6H4CO2C6H4OCnH2n+1)2]
    (1994)
    Deschenaux, Robert 
    ;
    Santiago, Julio
    ;
    Guillon, Daniel
    ;
    Heinrich, Benoit
    The title compds. were synthesized and their liq.-crystal properties studied. The reported ferrocene derivs. exhibited enantiotropic nematic and/or smectic A phases assocd. with broad anisotropic domains. The mol. arrangement within the smectic A phases was studied by x-ray diffraction. The exptl. data, compared to the values obtained from CPK models, suggested a monolayer mol. organization with a pronounced chain disorganization for the medium- and long-chain derivs. [on SciFinder(R)]
  • Publication
    Métadonnées seulement
    1,4-Bis(hex-yloxy)-2,5-diiodo-benzene
    (2010)
    Thevenet, Damien 
    ;
    Neier, Reinhard 
    ;
    Sereda, Olha
    ;
    Neels, Antonia
    ;
    Stoeckli-Evans, Helen 
    The centrosymmetric title compound, C(18)H(28)I(2)O(2), crystallized in the monoclinic space group P2(1)/c with the alkyl chains having extended all-trans conformations, similar to those in the centrosymmetric bromo analogue [Li et al. (2008 (black right triangle)). Acta Cryst. E64, o1930] that crystallized in the triclinic space group P. The difference between the two structures lies in the orientation of the two alkyl chains with respect to the C(aromatic)-O bond. In the title compound, the O-C(alk-yl)-C(alk-yl)-C(alk-yl) torsion angle is 55.8 (5)°, while in the bromo analogue this angle is -179.1 (2)°. In the title compound, the C-atoms of the alkyl chain are almost coplanar [maximum deviation of 0.052 (5) Å] and this mean plane is inclined to the benzene ring by 50.3 (3)°. In the bromo-analogue, these two mean planes are almost coplanar, making a dihedral angle of 4.1 (2)°. Another difference between the crystal structures of the two compounds is that in the title compound there are no halide(midline ellipsis)halide inter-actions. Instead, symmetry-related mol-ecules are linked via C-H(midline ellipsis)? contacts, forming a two-dimensional network.
  • Publication
    Métadonnées seulement
    1,4-Bis[4-(tert-butyl-diphenyl-silyl)buta-1,3-diyn-yl]benzene
    (2010)
    Thevenet, Damien 
    ;
    Neier, Reinhard 
    ;
    Stoeckli-Evans, Helen 
    The title centrosymmetric mol-ecule, C(46)H(42)Si(2), is composed of a central benzene ring with buta-1,3-diynyl chains at positions 1 and 4. These chains are terminated by tert-butyl-diphenyl-silyl groups, hence the molecule is dumbbell in shape. The mol-ecules are connected via C-H(midline ellipsis)? inter-actions in the structure, so forming an undulating two-dimensional network in the bc plane. There is also a weak ?-? inter-action involving centrosymmetrically related phenyl rings with a centroid-centroid distance of 3.8359 (11) Å.
  • Publication
    Accès libre
    1-Methoxycarbonyl-substituiertes 2,3-Dihydropyridin-4(1H)-on (= Methyl-1,2,3,4-tetrahydro-4-oxopyridin-1-carboxylat) als Chromophor für die photochemische [2 + 2]-Cycloaddition
    (1991)
    Guerry, Philippe
    ;
    Blanco, Philippe
    ;
    Brodbeck, Heinz
    ;
    Pasteris, Olivier
    ;
    Neier, Reinhard 
    With olefins having an electron-acceptor as well as with olefins having an electron-donor substituent, 1-methoxycarbonyl-substituted dihydropyridinone 12 undergoes [2 + 2] cycloaddition in good preparative yields. The photochemical cycloaddition is highly regioselective. For preparative purposes, the ring junction can be equilibrated to the thermodynamically more stable cis-junction. Only the ’endo’/’exo’ selectivity at the C-atom bearing the olefin substituent cannot be controlled. The photodimerization of 12 is the only side reaction. Using a slight excess of the olefin, the photodimerization can be suppressed. The protecting group at the N-atom of the dihydropyridinone can be varied in order to introduce an internal sensitizer, as shown with 1-acyl-substituted compound 29, which underwent the cycloaddition process even with sunlight.
  • Publication
    Accès libre
    1-Octen-3-Ol Isolated from Bont Ticks Attracts Amblyomma variegatum
    (2001)
    McMahon, Conor
    ;
    Guerin, Patrick 
    ;
    Syed, Zainulabeudin
    Volatiles from various life-stages of the bont ticks Amblyomma variegatum and A. hebraeum were collected by using solid-phase microfibers and charcoal traps. An octenol isomer was found to be a major constituent of most of the tick material sampled and was identified as 1-octen-3-ol by gas chromatography–mass spectrometry and by using antenna of the tsetse fly Glossina brevipalpis in gas chromatography-linked antennogram detection. Release of this compound increased during molt to adulthood and following mechanical disturbance of adult ticks. (R)-(–)-1-Octen-3-ol and racemate 1-octen-3-ol both induce an increase in upwind walk to the odor source from A. variegatum in an airstream on a servosphere. Volatiles from tick exuviae plus feces and from dead ticks also attracted A. variegatum, suggesting that 1-octen-3-ol may contribute to the aggregation response of Amblyomma spp. on such substrates. 2,6-Dichloroanisol and 2,5-dimethylpyrazine also were detected in volatiles from the ticks but induced no behavioral responses on the servosphere. The suspected tick pheromone component, 2,6-dichlorophenol, was detected from A. variegatum adults cut into pieces but had no effect on the behavior of A. variegatum on the servosphere at a range of doses.
  • Publication
    Accès libre
    1.55 µm InAs/GaAs Quantum Dots and High Repetition Rate Quantum Dot SESAM Mode-locked Laser
    Zhang, J. Y
    ;
    Oehler, A. E. H
    ;
    Resan, B
    ;
    Kurmulis, S
    ;
    Zhou, K. J
    ;
    Wang, Q
    ;
    Mangold, Mario
    ;
    Südmeyer, Thomas 
    ;
    Keller, Ursula
    ;
    Weingarten, K. J
    ;
    Hogg, R. A
    High pulse repetition rate (≥10 GHz) diode-pumped solid-state lasers, modelocked using semiconductor saturable absorber mirrors (SESAMs) are emerging as an enabling technology for high data rate coherent communication systems owing to their low noise and pulse-to-pulse optical phase-coherence. Quantum dot (QD) based SESAMs offer potential advantages to such laser systems in terms of reduced saturation fluence, broader bandwidth, and wavelength flexibility. Here, we describe the development of an epitaxial process for the realization of high optical quality 1.55 µm In(Ga)As QDs on GaAs substrates, their incorporation into a SESAM, and the realization of the first 10 GHz repetition rate QD-SESAM modelocked laser at 1.55 µm, exhibiting ∼2 ps pulse width from an Er-doped glass oscillator (ERGO). With a high areal dot density and strong light emission, this QD structure is a very promising candidate for many other applications, such as laser diodes, optical amplifiers, non-linear and photonic crystal based devices.
  • Publication
    Accès libre
    10 kHz linewidth mid-infrared quantum cascade laser by stabilization to an optical delay line
    Shehzad, Atif 
    ;
    Brochard, Pierre 
    ;
    Matthey, Renaud
    ;
    Südmeyer, Thomas 
    ;
    Schilt, Stephane 
    We present a mid-infrared quantum cascade laser (QCL) with a sub-10 kHz full width at half-maximum linewidth (at 1 s integration time) achieved by stabilization to a free-space optical delay line. The linear range in the center of a fringe detected at the output of an imbalanced Mach–Zehnder interferometer implemented with a short free-space pathlength difference of only 1 m is used as a frequency discriminator to detect the frequency fluctuations of the QCL. Feedback is applied to the QCL current to lock the laser frequency to the delay line. The application of this method in the mid-infrared is reported for the first time, to the best of our knowledge. By implementing it in a simple self-homodyne configuration, we have been able to reduce the frequency noise power spectral density of the QCL by almost 40 dB below 10 kHz Fourier frequency, leading to a linewidth reduction by a factor of almost 60 compared to the free-running laser. The present limits of the setup are assessed and discussed.
  • Publication
    Accès libre
    100 numéros, ça se… pense
    (2014)
    De Pietro, Jean-François
    ;
    Duchêne, Alexandre
    ;
    Kamber, Alain 
  • Publication
    Accès libre
  • Publication
    Accès libre
    13C- and 15N‑Isotope Analysis of Desphenylchloridazon by Liquid Chromatography−Isotope-Ratio Mass Spectrometry and Derivatization Gas Chromatography−Isotope-Ratio Mass Spectrometry
    (2019-1)
    Melsbach, Aileen
    ;
    Ponsin, Violaine 
    ;
    Lihl, Christina
    ;
    Torrento Aguerri, Clara 
    ;
    Hofstetter, Thomas B.
    ;
    Hunkeler, Daniel 
    ;
    Elsener, Martin
    The widespread application of herbicides impacts surface water and groundwater. Metabolites (e.g., desphenylchloridazon from chloridazon) may be persistent and even more polar than the parent herbicide, which increases the risk of groundwater contamination. When parent herbicides are still applied, metabolites are constantly formed and may also be degraded. Evaluating their degradation on the basis of concentration measurements is, therefore, difficult. This study presents compound-specific stableisotope analysis (CSIA) of nitrogen- and carbon-isotope ratios at natural abundances as an alternative analytical approach to track the origin, formation, and degradation of desphenylchloridazon (DPC), the major degradation product of the herbicide chloridazon. Methods were developed and validated for carbon- and nitrogen-isotope analysis (δ13C and δ15N) of DPC by liquid chromatography−isotope-ratio mass spectrometry (LC-IRMS) and derivatization gas chromatography−IRMS (GC-IRMS), respectively. Injecting standards directly onto an Atlantis LC-column resulted in reproducible δ13C-isotope analysis (standard deviation <0.5‰) by LC-IRMS with a limit of precise analysis of 996 ng of DPC on-column. Accurate and reproducible δ15N analysis with a standard deviation of <0.4‰ was achieved by GC-IRMS after derivatization of >100 ng of DPC with 160-fold excess of (trimethylsilyl)diazomethane. Application of the method to environmental-seepage water indicated that newly formed DPC could be distinguished from “old” DPC by the different isotopic signatures of the two DPC sources.
  • Publication
    Accès libre
    16.5 µm quantum cascade detector using miniband transport
    (2007)
    Giorgetta, Fabrizio R.
    ;
    Baumann, Esther
    ;
    Graf, Marcel
    ;
    Ajili, Lassaad
    ;
    Hoyler, Nicolas
    ;
    Marcella Giovannini,
    ;
    Faist, Jérôme
    ;
    Hofstetter, Daniel 
    ;
    Krötz, Peter
    ;
    Sonnabend, Guido
    The authors report on an InP based photovoltaic quantum cascade detector operating at 16.5 µm and using miniband-based vertical transport. This concept allowed the construction of a longitudinal optical phonon extraction stair with two rungs without touching on a high device resistance. At 10 K, they observed a responsivity of 1.72 mA/W and a Johnson noise limited detectivity of 2.2×109 Jones. Altogether, this design resulted in detection at temperatures of up to 90 K with a lower bandwidth limit of 200 MHz imposed by the measurement setup.
  • Publication
    Accès libre
    1649-1852 : deux siècles de l’honorable compagnie de la bannière d’Orvin
    (1999)
    Léchot, Pierre-Olivier 
    Cet article étudie le rôle joué par une corporation militaire censée être mobilisable en cas de conflit dans la vie sociale d’un petit village du Jura suisse. Il s’attache en particulier à dégager le rôle économique de ladite corporation, alors propriétaire, à l’instar de la paroisse du village, de nombreux bien fonciers ainsi que d’un « cabaret ».