Optical characterisation of germanium optical fibres

Semiconductor core optical fibres are currently generating great interest as they promise to be a platform for the seamless incorporation of optoelectronic functionality into a new generation of all-fibre networks [1,2]. Although recent attentions have primarily focused on silicon as the material of choice for semiconductor photonics applications, germanium has some advantages over its counterpart. For example, it has higher nonlinearity, extended infrared transparency and has recently been demonstrated as a direct band gap laser medium [3]. Here we present the first optical characterisation of a germanium core optical fibre. The fibre was fabricated using a chemical micro fluidic deposition process [1] that uses GeH4 (germane) as a precursor to deposit amorphous germanium into the hole of a silica capillary. Figure 1 (a) shows an optical microscope image of the polished end face of a germanium fibre, with a 5.6 µm core diameter, which has been completely filled with the semiconductor material. Optical transmission measurements have been conducted over the wavelength range 2 µm to 11 µm, to confirm the broad mid-infrared operational window, and the guided output at 2.4 µm, imaged using a Spiricon Pyrocam III pyroelectric array camera, is shown in Figure 1 (b). At this wavelength the optical loss has been measured to be 20 dB/cm, which is comparable to losses measured for amorphous silicon fibres in the infrared. The potential for these germanium optical fibres to be used as optical modulators and infrared detectors will be discussed

Economic Value Added and Small Businesses

Economic Value Added (EVA), a tool for creating wealth, is a leading idea in corporate finance today. Highly regarded companies like Coca-Cola and CSX have seen their market value soar since adopting EVA. The concept is straightforward; value is created when earnings exceed the cost of invested capital. Thus, EVA is rapidly gaining acceptance among large, publicly-traded corporations. However, EVA can be applied effectively to create value in small, privately-held firms, too. This article illustrates EVA's application in small, privately-held firms, examines EVA "s strengths and weaknesses, discusses ways to overcome those weaknesses, and describes specific operating, investing and financing actions small business managers can take to create wealth

Production Of Dna Minicircles Less Than 250 Base Pairs Through A Novel Concentrated Dna Circularization Assay Enabling Minicircle Design With Nf-κb Inhibition Activity

Double-stranded DNA minicircles of less than 1000 bp in length have great interest in both fundamental research and therapeutic applications. Although minicircles have shown promising activity in gene therapy thanks to their good biostability and better intracellular trafficking, minicircles down to 250 bp in size have not yet been investigated from the test tube to the cell for lack of an efficient production method. Herein, we report a novel versatile plasmidfree method for the production of DNA minicircles comprising fewer than 250 bp. We designed a linear nicked DNA double-stranded oligonucleotide bluntended substrate for efficient minicircle production in a ligase-mediated and bending protein-assisted circularization reaction at high DNA concentration of 2M. This one pot multi-step reaction based-method yields hundreds of micrograms of minicircle with sequences of any base composition and position and containing or not a variety of site-specifically chemical modifications or physiological supercoiling. Biochemical and cellular studies were then conducted to design a 95 bp minicircle capable of binding in vitro two NF-κB transcription factors per minicircle and to efficiently inhibiting NF-κB-dependent transcriptional activity in human cells. Therefore, our production method could pave the way for the design of minicircles as new decoy nucleic acids. © The Author(s) 2016.45

Structure of the specific combining ability between two species of Eucalyptus. II. A clustering approach and a multiplicative model

International audienceThe Eucalyptus breeding program of URPPI (a partnership between CIRAD-Fore t, Centre National de la Recherche Forestie re du Congo, and Unite dÕAforestation Industrielle du Congo) consists of a re- ciprocal recurrent selection scheme developed in the Congo between the two species Eucalyptus urophylla and Eucalyptus grandis. Two approaches are proposed in order to model and predict the speciÞc combining ability (SCA) between these species. The clustering ap- proach uses a simultaneous clustering procedure of the two species based on SCA and reveals heterotic groups coherent with the geographical origins of E. urophylla genotypes. The second approach uses a multiplicative model to partition the SCA into three multiplicative terms explaining 95% of the interactio

Tamari Lattices and the symmetric Thompson monoid

We investigate the connection between Tamari lattices and the Thompson group F, summarized in the fact that F is a group of fractions for a certain monoid F+sym whose Cayley graph includes all Tamari lattices. Under this correspondence, the Tamari lattice operations are the counterparts of the least common multiple and greatest common divisor operations in F+sym. As an application, we show that, for every n, there exists a length l chain in the nth Tamari lattice whose endpoints are at distance at most 12l/n.Comment: 35page

Structure of the specific combining ability between two species of Eucalyptus. I. RAPD data

International audienceWithin the context of the reciprocal recurrent selection scheme developed in 1989 by CIRAD-Fore t on Eucalyptus, RAPD essays were performed to assess the genetic diversity in the two species E. urophylla and E. grandis. The molecular markers were split into two parts: the speciÞc markers (present with di¤erent fre- quencies in the two species) and the common markers (present with similar frequencies in the two species). The study analyses the structure of genetic diversity within and between the two species of Eucalyptus. Dif- ferent genetic distances are worked out for use in pre- diction equations of the individual tree trunk volume of hybrids at 38 months. Each distance is expressed as the sum of the general genetic distance and the speciÞc genetic distance. The general genetic distance based on the double presence plus the double absence of bands seems to be an interesting co-variate to use in a factor regression model. Through this model the distance calculated between species explains the general com- bining ability (GCA) and the speciÞc combining ability (SCA) of the phenotypic character with a global coe¦c- ient of determination of 81.6

Effect of the oxygen content in solution on the static and cyclic deformation of titanium foams

It is well known that interstitials affect the mechanical properties of titanium and titanium alloys. Their effects on the fatigue properties of titanium foams have not, however, been documented in the literature. This paper presents the effect of the oxygen content on the static and dynamic compression properties of titanium foams. Increasing the oxygen content from 0.24 to 0.51 wt% O in solution significantly increases the yield strength and reduces the ductility of the foams. However, the fatigue limit is not significantly affected by the oxygen content and falls within the 92 MPa \ub1 12 MPa range for all specimens investigated in this study. During cyclic loading, deformation is initially coming from cumulative creep followed by the formation of microcracks. The coalescence of these microcracks is responsible for the rupture of the specimens. Fracture surfaces of the specimens having lower oxygen content show a more ductile aspect than the specimens having higher oxygen content.Il est bien connu que les interstices affectent les propri\ue9t\ue9s m\ue9caniques du titane et des alliages de titane. Leurs effets sur les propri\ue9t\ue9s de fatigue des mousses de titane n\u2019ont cependant pas encore \ue9t\ue9 document\ue9s dans la litt\ue9rature. Dans le pr\ue9sent article, on pr\ue9sente l\u2019effet de la teneur en oxyg\ue8ne sur les propri\ue9t\ue9s de compression statique et dynamique des mousses de titane. L\u2019augmentation de la teneur en oxyg\ue8ne de 0,24 \ue0 0,51 % en poids en solution accro\ueet de mani\ue8re significative la limite d\u2019\ue9lasticit\ue9 conventionnelle et r\ue9duit la ductilit\ue9 des mousses. Toutefois, la limite de fatigue n\u2019a pas \ue9t\ue9 affect\ue9e de mani\ue8re significative par une teneur en oxyg\ue8ne dans la gamme de 92 \ub1 12 MPa pour tous les \ue9chantillons test\ue9s dans le cadre de la pr\ue9sente \ue9tude. Pendant une charge cyclique, la d\ue9formation provient initialement d\u2019un fluage cumulatif, suivi par la formation de microfissures. La coalescence de ces microfissures est responsable de la rupture des \ue9chantillons. Les surfaces des fissures dans les \ue9chantillons ayant une teneur en oxyg\ue8ne plus faible exhibent un aspect plus ductile que celles des \ue9chantillons ayant une teneur plus \ue9lev\ue9e en oxyg\ue8ne.Peer reviewed: YesNRC publication: Ye