pinecone/core-2020-05-10-deduplication huggingface dataset:
Corrosion studies on Fe-30Mn-1C alloy in chloride-containing solutions with view to biomedical application

Austenitic Fe‐30Mn‐1C (FeMnC) is a prospective biodegradable implant material combining high mechanical integrity with adequate corrosion rates. The fast solidified TWIP alloy, its constituents and 316L stainless steel were electrochemically analysed in various electrolytes at 37 °C under laminar flow. Potentiodynamic polarization tests were conducted in Tris‐buffered simulated body fluid (SBF), in Tris‐buffered saline (TBS) and in 150–0.15 mM NaCl solutions (pH 7.6, 10, 5, 2) to study initial corrosion stages. Active dissolution of FeMnC is revealed in all electrolytes and is discussed on basis of the Fe and Mn behaviour plus is compared to that of 316L. The role of Tris (Tris(hydroxymethyl)aminomethane) as organic buffer for SBFs is critically assessed, particularly with view to the sensitivity of Fe. SEM studies of FeMnC corroded in NaCl revealed preferential dissolution along Mn‐rich grain boundary regions. Static immersion tests of FeMnC in SBF with surface and solution analyses (SEM/EDX, XPS, ICP‐OES) indicated that dissolution processes interfere with the formation of permeable surface coatings comprising hydroxides and salt
Aggregation of fillers blended into random elastomeric networks: Theory and comparison with experiments

A theoretical model describing aggregation of filler particles in amorphous elastomers is proposed. The model is based on a counting technique originally used in genome analysis to characterize the size and distribution of overlapping segments randomly placed on a DNA molecule. In the present model, the particles are first assumed to aggregate randomly upon mixing into the elastomer and then-sizes are calculated. The sizes and distributions of aggregates are also studied in the presence of attractive interparticle forces. Results of the proposed model are compared with experimental data on silica-filled end-linked poly(dimethyl-siloxane) networks. Comparison of the theory and experiment shows that the random aggregation assumption where no attractive forces exist between the particles is not valid and a significant attraction between the silica particles is needed in the theory to justify the experimental data obtained using atomic force microscopy. For filler content below 1.45 vol.-%, the model agrees, qualitatively, with experiment and shows the increase in cluster size with increasing amount of filler. It also explains the increase in the dispersion of aggregate sizes with increasing amount of filler
A New Family of Styrene/Diene Rubbers

International audienceThe insertion of single styrene units into polyisoprene is demonstrated using borohydrido rare earth/dialkylmagnesium systems. This yields a new family of styrene/diene copolymers (SBR rubbers). The resulting poly[(1,4-trans-isoprene)-co-styrene] exhibits quite narrow molecular weight distributions, up to 30% inserted styrene, and a 96–98% 1,4-trans-microstructure. The presence of a bulky and electron-rich ligand in the coordination sphere of the metal leads to an increase of the amount of styrene inserted and narrower chemical composition and molecular weight distributions. The presence of significant quantities of styrene in the medium does not alter the selectivity of the reaction, in contrast with cis-specific polymerizations
Synthesis of Poly(N-aryl-2,7-carbazole)s for Efficient Blue Electroluminescence Materials

Several poly(N-phenyl-2,7-carbazole)s that have dialkoxy groups at the m- and p-positions (PmpCzDC, PmpPhDC, PmpCBiDC, PmpEHC), a silyl group at the p-position (PpPhDSiC), and a diphenylamino group (PmPhDAC, PmEHAC) at the m-position of the N-phenyl portion are synthesized, and their optical properties are characterized. These polymers have been used as emitting layer materials of organic light-emitting diode (OLED) devices that have a configuration of ITO/PEDOT(PSS)/polymer/CsF/Al. The OLED devices embedded with PmpCzDC, PmpPhDC, and PmpEHC show intense luminance of about 15 000 cd ｷ m-2 with efficiencies of about 1 cd ｷ A-1, while the devices embedded with PpPhDSiC, PmPhDAC, and PmEHAC show less luminance but retain the color purity of blue emission under a wide range of applied voltages
Phosphorus-containing sulfonated polyimides for proton exchange membranes

Synthesis and characterization of the novel sulfonated BAPPO monomer and its use in the synthesis of a new phosphine oxide-based sulfonated polyimide are described. BTDA, 6FDA, and DDS were used as monomers in the polyimide synthesis. Sulfonated polyimide membranes were obtained by a solution thermal imidization method. The thermal behavior of the polymers was investigated by DSC and TGA. The morphological structure of the membranes was investigated by tapping-mode AFM. The proton conductivities of the sulfonated polyimide increased regularly as a function of sulfonated diamine content. The conductivities are good compared to typical proton exchange membranes
Straightforward determination of the degree of N-acetylation of chitosan by means of first-derivative UV spectrophotometry

First-derivative UV spectrophotometry is shown to be a reliable method for the determination
of the degree of N-acetylation of chitosan samples. A mathematical expression is derived that
allows to determine the DA directly from the mass concentration of a chitosan solution and
the first derivative of its UV spectrum at 202 nm, thus eliminating the need for empiric
correction curves for highly deacetylated
samples. A procedure is proposed for the accurate
mass determination of the hygroscopic
chitosan. The proposed approach facilitates
the routine determination of the DA, especially
when using potent multiwell microplate readers,
which allow hundreds of samples to be
measured in just a few minutes
Peroxide grafted PDMS: hydrosilylation reaction study and thiol-ene chemistry as an alternative pathway

International audiencePeroxide containing PDMS were synthesized according to a new pathway. Although hydrosilylation is one of the main reaction carried out in silicone chemistry, the catalysts used are very sensitive to the chemical nature of the reactants and remained inefficient to graft allylic peroxide. Radical catalyzed thiol-ene chemistry was involved for the first time to yield an initiator group containing polymer. Peroxide grafted polysiloxane structure and decomposition were characterized using 1H, 13C and 29Si NMR, FT-IR and RAMAN spectroscopies, SEC and DSC. These macroinitiators can be used to obtain polysiloxane able to undergo cross-linking
Polymeric Squaraine Dyes as Electron Donors in Bulk Heterojunction Solar
  Cells

A polysquaraine low band gap polymer was synthesized by Yamamoto coupling of
a monomeric dibromo indolenine squaraine dye. The resulting polymer has a
weight average molar mass in the order of Mw ~30.000-50.000 and a
polydispersity of ca. 1.7 as determined by gel-permeation chromatography (GPC).
The electronic properties of monomer and polymer were investigated by cyclic
voltammetry, absorption and emission spectroscopy. Owing to exciton coupling
the absorption bands of the polymer are red-shifted and strongly broadened
compared to the monomer squaraine dye. Bulk heterojunction solar cells were
prepared from blends of the polysquaraine with the fullerene derivative
[6,6]-phenyl C61-butyric acid methyl ester (PCBM) in different weight ratios
(1:3 to 1:1). The power conversion efficiencies under simulated AM 1.5
conditions yielded 0.45 % for these non-optimized systems. The external quantum
efficiency (EQE) shows that the photoresponse spans the range from 300 to 850
nm, which illustrates the promising properties of this novel organic
semiconductor as a low band gap donor material in organic photovoltaics.Comment: 10 pages, 7 figure
Polyterthiophenes incorporating 3,4-difluorothiophene units : application in organic field-effect transistors

Two terthiophenes bearing core fluorinated thienyl units have been synthesised as potential semiconductor materials for organic field-effect transistors. Polymerisation of these compounds has been achieved using conventional iron(III) chloride oxidative coupling methods and by electrochemical oxidation. Characterisation of the fluorinated materials has been achieved by absorption spectroscopy and cyclic voltammetry. A soluble hexyl-functionalised polymer (poly8b) was used in an OFET device; hole mobilities were measured up to 3 × 10−3 cm2 · V−1 · s−1, and the device had an on/off ratio of 105 and a turn-on voltage of +4 V
Controlled One-Pot Synthesis of Polystyrene-block-Polycaprolactone Copolymers by Simultaneous RAFT and ROP

A convenient one-pot method for the controlled synthesis of polystyrene- block -polycaprolactone (PS- b -PCL) copolymers by simultaneous reversible addition?fragmentation chain transfer (RAFT) and ring-opening polymerization (ROP) processes is reported. The strategy involves the  use of 2-(benzylsulfanylthiocarbonylsulfanyl)ethanol (1) for the dual roles of chain transfer agent (CTA) in the RAFT polymerization of styrene and co-initiator in the ROP of ε -caprolactone.  One-pot poly merizations using the electrochemically stable ROP catalyst diphenyl phosphate (DPP) yield well-defi ned PS- b -PCL in a relatively short reaction time (≈4 h; Mn = 9600−43 600 g mol−1 ; Mw/Mn = 1.21−1.57). Because the hydroxyl group is strategically located on the Z substituent of the CTA, segments of these diblock copolymers are connected through  a trithiocarbonate group, thus offering an easy way for subsequent growth of a third segment between PS and PCL. In contrast, an oxidatively  unstable Sn(Oct) 2 ROP catalyst reacts with (1) leading to multimodal distributions of polymer chains with variable composition.Fil: de Freitas, Augusto G. O.. Universidade Federal de Santa Maria; BrasilFil: Trindade, Suelen G.. Universidade Federal de Santa Maria; BrasilFil: Muraro, Paulo I. R.. Universidade Federal de Santa Maria; BrasilFil: Schmidt, Vanessa. Universidade Federal de Santa Maria; BrasilFil: Satti, Angel Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Planta Piloto de Ingeniería Química (i); ArgentinaFil: Villar, Marcelo Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Planta Piloto de Ingeniería Química (i); ArgentinaFil: Ciolino, Andrés Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Planta Piloto de Ingeniería Química (i); ArgentinaFil: Giacomelli, Cristiano. Universidade Federal de Santa Maria; Brasi
A novel method of extraction of blend component structure from SANS measurements of homopolymer bimodal blends.

A new method is presented for the extraction of single-chain form factors and interchain interference functions from a range of small-angle neutron scattering (SANS) experiments on bimodal homopolymer blends. The method requires a minimum of three blends, made up of hydrogenated and deuterated components with matched degree of polymerization at two different chain lengths, but with carefully varying deuteration levels. The method is validated through an experimental study on polystyrene homopolymer bimodal blends with inline image. By fitting Debye functions to the structure factors, it is shown that there is good agreement between the molar mass of the components obtained from SANS and from chromatography. The extraction method also enables, for the first time, interchain scattering functions to be produced for scattering between chains of different lengths. \u
Solution-Processable Donor-Acceptor-Donor Oligomers with Cross-Linkable Functionality

Electron-acceptor units, combined with bithiophene substituted with flexible chains end-functionalized with cross-linkable moieties, provide soluble donor-acceptor-donor (DAD) it-conjugated oligomer-type molecules with cross-linking ability and broad absorption in the visible spectrum. A study on the cross-linking conditions of the new oligomers to yield insoluble polymer networks is presented, including conditions for obtaining polymer films over poly(3,4-ethylenedioxythiophene):polystyrene sulfonate-covered substrates. The combination of the DAD molecular design and cross-linking functionality opens prospects for applications in solution-processed small-molecule solar cells with morphologically-stable organic layers
Termination of Living Anionic Polymerization of Butyl Acrylate with alpha-(Chloromethyl) acrylate for End-Functionalization and Application to the Evaluation of Monomer Reactivity

Article first published online: 11 JUN 2015Anionic polymerization of n-butyl acrylate (nBA) in toluene initiated with a binary initiator, isopropyl α-lithioisobutyrate/ethylaluminum bis(2,6-di-tert-butylphenoxide) at −60 °C, is terminated with ethyl α-(chloromethyl)acrylate (ECMA) to afford a poly(nBA) possessing an acryloyl group at the terminal with 80% of termination efficiency. The reactivity of nBA against a polymer anion of methyl methacrylate formed under identical conditions is estimated relative to the termination with ECMA by reacting a mixture of nBA and ECMA followed by 1H NMR spectroscopic chain-end analysis; the relative reactivity of nBA is found 80 times or more higher than ECMA
Thermomechanical properties and shape-memory behavior of bisphenol a diacrylate-based shape-memory polymers

A series of acrylate-based shape-memory materials are synthesized from bisphenol A diacrylate monomers as crosslinking agents. Networks are synthesized by keeping constant the content of bisphenol A-based crosslinking agent and systematically varying the content ratio of different monofunctional chain builder monomers. The implications of the structure of bisphenol A-based monomers and the chemical structure and content of monofunctional monomers on thermomechanical properties are discussed. Thermomechanical properties are analyzed using dynamic mechanical analyses and mechanical properties are studied at room temperature and at the onset of the glass transition temperature. Shape-memory performances under isothermal and transient temperature conditions are also carried out. Tensile tests show excellent values of stress at break up to 45 and 15 MPa at room and high temperature, respectively. The measurements show excellent shape recovery and shape fixity ratios, ˜95% and 97%, respectively. These materials also show very high recovery velocities under transient temperature conditions, up to 24% min-1, and very short recovery times, up to 1.5 s, under isothermal conditions in a water bath. The results confirm that networks synthesized from bisphenol A crosslinkers are promising shape-memory materials.Postprint (author's final draft
Sporopollenin, a natural copolymer, is robust under high hydrostatic pressure

Lycopodium sporopollenin, a natural copolymer, shows exceptional stability under high hydrostatic pressures (10 GPa) as determined by in situ high pressure synchrotron source FTIR spectroscopy. This stability is evaluated in terms of the component compounds of the sporopollenin: p-coumaric acid, phloretic acid, ferulic acid, and palmitic and sebacic acids, which represent the additional n-acid and ndiacid components. This high stability is attributed to interactions between these components, rather than the exceptional stability of any one molecular component. We propose a biomimetic solution for the creation of polymer materials that can withstand high pressures for a multitude of uses in aeronautics, vascular autografts, ballistics and light-weight protective materials
Thermoresponsive UCST-Type Behavior of Interpolymer Complexes of Poly(ethylene glycol) and Poly(poly(ethylene glycol) methacrylate) Brushes with Poly(acrylic acid) in Isopropanol

Upper critical solution temperature (UCST)-type thermoresponsive behavior of poly(ethylene glycol)-poly(acrylic acid) (PEG-PAA) and poly(poly(ethylene glycol) methacrylate)-poly(acrylic acid) (PPEGMA-PAA) interpolymer complexes has been observed in isopropanol. For these investigations, PPEGMA and PAA with various average molecular weights have been synthesized by atom transfer radical polymerization. It has been found that both the PEG and PPEGMA have lower cloud point temperatures (Tcp) than its mixed polymer solutions with PAA, whereas PAA does not show such behavior in the investigated temperature range. These findings indicate the reversible formation of interpolymer complexes with variable structure and composition in the solutions of the polymer mixtures in isopropanol. Increasing the ethylene glycol/acrylic acid molar ratio or the molecular weight of either the PAA or the H-acceptor PEG component of the interpolymer complexes increases the UCST-type cloud point temperatures of these interpolymer systems. The polymer-polymer interactions by hydrogen bonds between PAA and PEG or PPEGMA and the correlations between Tcp and structural parameters of the components revealed in the course of these investigations may be utilized for exploring well-defined UCST-type material systems for various applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
End-functionalized chains via anionic polymerization : can the problems with using diphenylethylene derivatives be solved by using bisphenol F?

The controlled functionalization of polymers via anionic polymerization draws great attention not only because of the importance of introducing functionality into otherwise unfunctionalized polymers, but also because of the possibility to use the resulting macromonomers to make a variety of complex architectures. The versatile family of 1,1-diphenylethylene (DPE) derivatives is widely used to produce many different functionalized (co)polymers. DPE can be added either as an end-capping agent or be activated by butyllithium to initiate the polymerization. However, each approach faces potential problems in gaining precise control over the number of DPE moieties per chain. In this work, for the first time, the effectiveness of each approach is compared by the characterization of 1,1-bis(4-tert-butyldimethylsiloxyphenyl)ethylene functionalized polystyrene, synthesized via both the procedures. A combination of NMR, size exclusion chromatography, matrix-assisted laser desorption ionization-time of flight (MALDI-ToF) mass spectrometry, and interaction chromatography is used. To overcome the limitations of DPE derivatives, the use of a novel (protected) bisphenol F potassium initiator is proposed
Some recent developments on Shannon's General Purpose Analog Computer

This paper revisits one of the  rst models of analog computation, the
General Purpose Analog Computer (GPAC). In particular, we restrict our
attention to the improved model presented in [11] and we show that it
can be further re ned. With this we prove the following: (i) the previous
model can be simpli ed; (ii) it admits extensions having close connec-
tions with the class of smooth continuous time dynamical systems. As a
consequence, we conclude that some of these extensions achieve Turing
universality. Finally, it is shown that if we introduce a new notion of
computability for the GPAC, based on ideas from computable analysis,
then one can compute transcendentally transcendental functions such as
the Gamma function or Riemann's Zeta function
An extension of Chaitin's halting probability \Omega to a measurement
  operator in an infinite dimensional quantum system

This paper proposes an extension of Chaitin's halting probability \Omega to a
measurement operator in an infinite dimensional quantum system. Chaitin's
\Omega is defined as the probability that the universal self-delimiting Turing
machine U halts, and plays a central role in the development of algorithmic
information theory. In the theory, there are two equivalent ways to define the
program-size complexity H(s) of a given finite binary string s. In the standard
way, H(s) is defined as the length of the shortest input string for U to output
s. In the other way, the so-called universal probability m is introduced first,
and then H(s) is defined as -log_2 m(s) without reference to the concept of
program-size.
  Mathematically, the statistics of outcomes in a quantum measurement are
described by a positive operator-valued measure (POVM) in the most general
setting. Based on the theory of computability structures on a Banach space
developed by Pour-El and Richards, we extend the universal probability to an
analogue of POVM in an infinite dimensional quantum system, called a universal
semi-POVM. We also give another characterization of Chaitin's \Omega numbers by
universal probabilities. Then, based on this characterization, we propose to
define an extension of \Omega as a sum of the POVM elements of a universal
semi-POVM. The validity of this definition is discussed.
  In what follows, we introduce an operator version \hat{H}(s) of H(s) in a
Hilbert space of infinite dimension using a universal semi-POVM, and study its
properties.Comment: 24 pages, LaTeX2e, no figures, accepted for publication in
  Mathematical Logic Quarterly: The title was slightly changed and a section on
  an operator-valued algorithmic information theory was adde
Set theoretical Representations of Integers, I.

56 pagesInternational audienceWe reconsider some classical natural semantics of integers (namely iterators of functions, cardinals of sets, index of equivalence relations), in the perspective of Kolmogorov complexity. To each such semantics one can attach a simple representation of integers that we suitably effectivize in order to develop an associated Kolmogorov theory. Such effectivizations are particular instances of a general notion of "self-enumerated system" that we introduce in this paper. Our main result asserts that, with such effectivizations, Kolmogorov theory allows to quantitatively distinguish the underlying semantics. We characterize the families obtained by such effectivizations and prove that the associated Kolmogorov complexities constitute a hierarchy which coincides with that of Kolmogorov complexities defined via jump oracles and/or infinite computations. This contrasts with the well-known fact that usual Kolmogorov complexity does not depend (up to a constant) on the chosen arithmetic representation of integers, let it be in any base unary, binary et so on. Also, in a conceptual point of view, our result can be seen as a mean to measure the degree of abstraction of these diverse semantics
A notion of selective ultrafilter corresponding to topological Ramsey
  spaces

We introduce the relation of "almost-reduction" in an arbitrary topological
Ramsey space R, as a generalization of the relation of "almost-inclusion" on
the space of infinite sets of natural numbers (the Ellentuck space). This leads
us to a type of ultrafilter U on the set of first approximations of the
elements of R which corresponds to the well-known notion of "selective
ultrafilter" on N, the set of natural numbers. The relationship turns out to be
rather exact in the sense that it permits us to lift several well-known facts
about selective ultrafilters on N and the Ellentuck space to the ultrafilter U
and the Ramsey space R. For example, we prove that the Open Coloring Axiom
holds in M[U], where M is a Solovay model. In this way we extend a result due
to Di Prisco and Todorcevic which gives the same conclusion for the Ellentuck
space.Comment: 24 pages; submitted to Mathematical Logic Quarterl