bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of original alternated fluorinated copolymers bearing glycidyl carbonate side groups
Authors: Alaaeddine Ali , Boschet Frédéric , Ameduri Bruno , Boutevin Bernard 
Published: May 2012

AbstractA vinyl ether bearing a carbonate side group (2‐oxo‐1,3‐dioxolan‐4‐yl‐methyl vinyl ether, GCVE) was synthesized and copolymerized with various commercially available fluoroolefins [chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), and perfluoromethyl vinyl ether (PMVE)] by radical copolymerization initiated by tert‐butyl peroxypivalate. Although HFP, PMVE, and vinyl ether do not homopolymerize under radical conditions, they copolymerized easily yielding alternating poly(GCVE‐alt‐F‐alkene) copolymers. These alternating structures were confirmed by elemental analysis as well as 1H, 19F, and 13C NMR spectroscopy. All copolymers were obtained in good yield (73–85%), with molecular weights ranging from 3900 to 4600 g mol−1 and polydispersities below 2.0. Their thermogravimetric analyses under air showed decomposition temperatures at 10% weight loss (Td,10%) in the 284–330°C range. The HFP‐based copolymer exhibited a better thermal stability than those based on CTFE and PMVE. The glass transition temperatures were in the 15–65°C range. These original copolymers may find potential interest as polymer electrolytes in lithium ions batteries. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Cyclodextrin functionalization: Simple routes to tailored solubilities and nanoscopic polymer networks
Authors: Gyanwali Gaumani , Hodge Mathis , White Jeffery L. 
Published: May 2012

AbstractThe systematic chemical modification of cyclodextrins (CDs) provides an opportunity to create new substances with novel phase transfer, guest–host, solubility, and network properties. Such materials have several potential applications in polymer science, including free‐volume modifiers, stabilizers or compatibilizers, and scaffolds or templates for synthesizing new materials. In this study, we describe simple, inexpensive, and easy purification one‐pot methods to selectively functionalize CD rings with short‐ and long‐chain alkyl derivatives of varying polarity. Using bifunctional reagents in the same reaction scheme yields CD‐based polymer networks. Particular attention is devoted to solution and solid‐state NMR experiments that reveal the type and extent of functionalization, which may be used to control solubility and swelling. Alkyl chain functionalization may be expressed as the average number of CH2 units attached per CD ring, the magnitude of which can reach at least 16 and the product still be water soluble, but products become insoluble in water at a value of 32. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Influencing the phase transition temperature of poly(methoxy diethylene glycol acrylate) by molar mass, end groups, and polymer architecture
Authors: Miasnikova Anna , Laschewsky André 
Published: May 2012

AbstractThe easily accessible, but virtually overlooked monomer methoxy diethylene glycol acrylate was polymerized by the RAFT method using monofunctional, difunctional, and trifunctional trithiocarbonates to afford thermoresponsive polymers exhibiting lower critical solution temperature‐type phase transitions in aqueous solution. The use of the appropriate RAFT agent allowed for the preparation and systematic variation of polymers with defined molar mass, end‐groups, and architecture, including amphiphilic diblock, symmetrical triblock, and triarm star‐block copolymers, containing polystyrene as permanently hydrophobic constituent. The cloud points (CPs) of the various polymers proved to be sensitive to all varied parameters, namely molar mass, nature, and number of the end‐groups, and the architecture, up to relatively high molar masses. Thus, CPs of the polymers can be adjusted within the physiological interesting range of 20–40 °C. Remarkably, CPs increased with the molar mass, even when hydrophilic end groups were attached to the polymers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Reactive polythiophenes with zincke salt structure: Synthesis, polymer reactions, and chemical properties
Authors: Yamaguchi Isao , Nakahara Takuya 
Published: May 2012

AbstractPolythiophenes with reactive Zincke salt structure, such as PThThPy+DNP(Cl−)Th, were synthesized by the oxidation polymerization of 3′‐(4‐N‐(2,4‐dinitrophenyl)pyridinium chloride)‐2,2′:5′,2″‐terthiophene (ThThPy+DNP(Cl−)Th) with iron(III) chloride or copper(II) trifluoromethanesulfonate. The reaction of PThThPy+DNP(Cl−)Th with R‐NH2 (R = n‐hexyl (Hex) and phenyl (Ph)) substituted the 2,4‐dinitrophenyl group into the R group with the elimination of 2,4‐dinitroaniline to yield PThThPy+R(Cl−)Th. Similarly, model compounds, ThThPy+R(Cl−)Th (R = Hex and Ph), were also synthesized. In contrast to the photoluminescent ThThPyTh and PThThPyTh, the compounds PThThPy+DNP(Cl−)Th, PThThPy+R(Cl−)Th, and ThThPy+R(Cl−)Th showed no photoluminescence because their internal pyridinium rings acted as quenchers. Cyclic voltammetry measurements suggested that PThThPy+DNP(Cl−)Th received an electrochemical reduction of the pyridinium and 2,4‐dinitrophenyl groups and oxidation of the polymer backbone. PThThPy+DNP(Cl−)Th was electrically conductive (ρ = 2.0 × 10−6 S cm−1) in the non‐doped state. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Multilayered polycarbonate/poly(vinylidene fluoride‐co‐hexafluoropropylene) for high energy density capacitors with enhanced lifetime
Authors: Zhou Zheng , Mackey Matt , Carr Joel , Zhu Lei , Flandin Lionel , Baer Eric 
Published: May 2012

AbstractThe dielectric lifetime and corresponding damage morphology of polycarbonate/poly(vinylidene fluoride‐co‐hexafluoropropylene) (PC/P(VDF‐HFP)) layered systems are studied under constant direct current (DC) field. Melt blends of the two polymers are also considered for comparison. The dielectric lifetimes of the latter are systematically much shorter than the layered systems. The interfaces between the polymers act as flaws that induce up to two orders of magnitude difference between the layered and blend systems. The capacitance values versus time during breakdown progression exhibit an inversed S‐shape pattern. The three regimes in the S‐shape pattern are consecutively attributed to randomly isolated breakdowns, interconnecting breakdowns, and wearing‐out of the capacitor film. The film breakdown images during dielectric lifetime test confirmed the transition from randomly isolated breakdowns to interconnecting breakdowns. This transition was further evidenced by a bimodal distribution in the Weibull analysis. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Structural analysis of poly(amidoamine) dendrimer immobilized in crosslinked poly(ethylene glycol)
Authors: Taniguchi Ikuo , Kazama Shingo , Jinnai Hiroshi 
Published: May 2012

AbstractPolymeric membranes comprised of poly(amidoamine) (PAMAM) dendrimer immobilized in a poly(ethylene glycol) (PEG) network exhibit an excellent CO2 separation selectivity over H2. The CO2 permeability increases with PAMAM dendrimer concentration in the polymeric membrane and becomes 500 times greater than H2 permeability when the dendrimer content was 50 wt % at ambient conditions (5 kPa of CO2 partial pressure). However, the detailed morphology of the membrane has not been discussed. The immiscibility of PAMAM dendrimer and PEG matrix results in phase separation, which takes place in a couple of microns scale. Especially, laser scanning confocal microscope captures a 3D morphology of the polymeric blend. The obtained 3D reconstructions demonstrate a bicontinuous structure of PAMAM dendrimer‐rich and PEG‐rich phases, which indicates the presence of PAMAM dendrimer channel penetrating the polymeric membrane, and CO2 will preferentially pass through the dendrimer channel. In addition, Fourier transform of the 3D reconstructions indicates the presence of a periodic structure. An average size of the dendrimer domain calculated is 2–4 μm in proportion to PAMAM dendrimer concentration. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Enhancing patient participation in oncology consultations: a best evidence synthesis of patient‐targeted interventions
Authors: Henselmans Inge , de Haes Hanneke C. J. M. , Smets Ellen M. A. 
Published: May 2012

AbstractObjectiveBecause of the complexity of cancer consultations, the contribution of patients is often limited. This systematic review examined the characteristics and effectiveness of patient‐targeted interventions that aim to enhance cancer patients' participation in the consultation.MethodsRelevant studies were selected by a search of databases until mid‐2010 (Pubmed, PsycINFO and CINAHL), citations in relevant reviews as well as backward/forward citations. A Best Evidence Synthesis was performed, taking into account the quality of studies.ResultsA total of 52 publications were included, describing 46 studies and 30 unique interventions. One‐third was delivered through either written or multimedia material, two‐thirds face to face. Most originated from English‐speaking countries. Half targeted heterogeneous cancer populations, one‐third targeted women with breast cancer. Half focussed on initial treatment‐planning consultations. Overall, there was evidence for an effect on observed patient participation. There was no evidence for an effect on patient or doctor satisfaction and insufficient evidence for an effect on psychological well‐being, physical well‐being and consultation duration. The findings turned out to be largely independent of study quality.ConclusionsEffect of the interventions could only be demonstrated for immediate outcomes, that is, behaviour observed in the consultation. Implications for future research are discussed, including attention for gaps in the literature as well as the choice of outcome measures. Copyright © 2012 John Wiley & Sons, Ltd.
Use of PCA3 in detecting prostate cancer in initial and repeat prostate biopsy patients
Authors: Goode Roland R. , Marshall Susan J. , Duff Michael , Chevli Eric , Chevli K. Kent 
Published: May 2012

AbstractBACKGROUNDThe PCA3 urinary assay has shown promise in predicting the presence of prostate cancer. We evaluated the value of this test in patients undergoing initial and repeat prostate biopsy.METHODSPCA3 and PSA levels were obtained from 456 men with no known personal history of prostate cancer prior to prostate biopsy. Two hundred eighty‐nine men underwent an initial prostate biopsy and 167 underwent a repeat prostate biopsy. PCA3 and PSA levels were compared to the prostate biopsy results.RESULTSPCA3 score was shown to be independent of prostate volume (P = 0.162) and PSA level (P = 0.959). PCA3 scores were significantly higher in patients with cancer on prostate biopsy compared to patients with negative biopsy results (P < 0.0001). In logistic regression, PCA3 showed a significantly higher AUC than PSA (0.726 vs. 0.512, P = 0.0001). This difference persisted when examining the initial biopsy subgroup, with PCA3 out‐performing PSA (AUC 0.772 vs. AUC = 0.552, P < 0.0001), but not in the repeat biopsy subgroup (AUC = 0.605 vs. AUC = 0.500, P = 0.2488).CONCLUSIONSPCA3 was found to be a better predictor of prostate cancer than PSA in the total population as well as the initial biopsy population, but was not superior to PSA in the repeat biopsy population. Prostate 73: 48–53, 2013. © 2012 Wiley Periodicals, Inc.
Backside‐electrode effects on current collapse in field‐plate AlGaN/GaN HEMTs
Authors: Horio Kazushige , Onodera Hiraku 
Published: May 2012

AbstractTwo‐dimensional transient analysis of field‐plate AlGaN/GaN HEMTs with a backside electrode is performed by considering the use of a deep donor and a deep acceptor in a buffer layer. Effects of introducing the field plate and backside electrode on buffer‐related current collapse are studied. It is shown that the introduction of field plate is effective in reducing current collapse when the acceptor density in the buffer layer is high. On the other hand, the introduction of backside electrode is shown to be effective in reducing current collapse when the acceptor density in the buffer layer is relatively low, because the fixed potential at the backside electrode reduces electron injection into the buffer layer and the resulting trapping effects (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Radiation hardness of single‐crystalline zinc oxide films
Authors: Koike Kazuto , Aoki Takahiro , Fujimoto Ryugo , Sasa Shigehiko , Yano Mitsuaki , Gonda Shun‐ichi , Ishigami Ryoya , Kume Kyo 
Published: May 2012

AbstractZinc oxide (ZnO) is a potential semiconductor to exhibit high radiation hardness since large threshold displacement energy for damage can be expected due to the small unit‐cell volume and large bandgap energy. In order to study the radiation hardness, single‐crystalline c‐axis‐oriented ZnO films with and without two‐dimensional electron gas, and bulk crystals of ZnO and gallium nitride (GaN) for comparison, were irradiated with 8 MeV protons at the wide range of fluences from 2×1013 to 1×1017 p/cm2. For both ZnO films, decrease of luminescence intensity followed by increase of electrical resistance was observed at larger fluences than ∼5×1014 p/cm2. This threshold fluence was found to be much larger and larger than those of GaN and ZnO bulk crystals, respectively, indicating that ZnO thin films should be useful for such device applications as the electronics for space satellites and nuclear reactors. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural studies of GaN1‐x Asx and GaN1‐x Bix alloys for solar cell applications
Authors: Liliental‐Weber Z. , dos Reis R. , Levander A. X. , Yu K. M. , Walukiewicz W. , Novikov S. V. , Foxon C. T. 
Published: May 2012

AbstractWe have discovered materials with a wide tunability of the band gap that opens the possibility to achieve a desirable material for multi‐junction solar cells. Two different alloy systems have been studied. GaN1‐xAsx alloys over the entire composition range were grown by plasma‐assisted MBE at low temperature on crystalline and amorphous (glass) substrates. For growth on sapphire the alloys are amorphous in the composition range of 0.17<x<0.75, but for growth on glass the composition range for amorphous alloys extends to x∼0.1. The bandgap of the GaN1‐xAsx alloys ranges from 3.4‐0.7 eV, covering a large part of the solar spectrum, therefore this material is potentially useful for solar energy conversion.The substitution of N by Bi in GaN forming GaN1‐x Bix is extremely difficult since Bi and N have even larger differences in size and electronegativity. TEM studies of GaN1‐xBix with x up to 0.2 show that the alloy is not entirely amorphous. Small crystallites embedded in an amorphous matrix are observed and Bi segregation was confirmed by Electron Energy Loss studies. A strong reduction in band gap is observed in samples with increasing Bi, suggesting the formation of a random alloy but low energy absorption tail may be related to the presence of the crystallites observed by TEM (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Luminescence properties of Ag‐, Ga‐doped ZnO and ZnO‐ZnS thin films
Authors: Kushnirenko V. I. , Khomchenko V. S. , Zashivailo T. V. , Zavyalova L. V. 
Published: May 2012

AbstractThin films of ZnS were grown by metal‐organic chemical vapor deposition (MOCVD) method under atmospheric pressure onto glass substrates. ZnO–ZnS:[Ag, Ga] and ZnO:[Ag, Ga] thin films were prepared by oxidation and Ag, Ga doping of ZnS films at temperatures of 700–775 °C for 0.5–1 h. Crystalline quality and luminescent properties were investigated using X‐ray diffraction (XRD), atomic force microscopy (AFM), and photoluminescence. It is found that the doped films have a polycrystalline structure without preferred orientation and consist of small grains gathered into conglomerates. The shape of photoluminescence (PL) spectra of the films depends strongly on the preparation conditions. The ZnO–ZnS:[Ag, Ga] films exhibited the blue and green emission connected with the presence of silver and oxygen, respectively. The ZnO:[Ag, Ga] films revealed the white emission originated from different defect‐related transitions. The possible origin of radiative centers is discussed (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Metalorganic vapor phase epitaxial growth of (211)B CdTe on nanopatterned (211)Si
Authors: Shintri Shashidhar , Rao Sunil , Schaper Charles , Palosz Witold , Trivedi Sudhir , Semendy Fred , Wijewarnasuriya Priyalal , Bhat Ishwara 
Published: May 2012

AbstractLow‐defect density epitaxial CdTe on Si is very crucial for fabricating high performance HgCdTe IR focal planar arrays on Si. This paper discusses a novel nanopatterning technique to explore defect reduction in CdTe epitaxy on (211)Si. Nanopatterning of full 3″ (211)Si wafers was done by growing a thin layer of thermal SiO2 and patterning by molecular transfer lithography (MxL) based on water‐soluble templates. Conditions for obtaining selective Ge and CdTe were obtained in the temperature range of 575‐675 °C and 505‐520 °C respectively. X‐ray analysis of thin CdTe films grown on these substrates gave wider full‐width half‐maximum (FWHM) values when compared to the layers grown on blanket (non‐patterned) (211)Si, which is attributed to some patterning defects and spurious nucleation on oxide side walls. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Future high temperature applications for SiC integrated circuits
Authors: Zetterling Carl‐Mikael , Lanni Luigia , Ghandi Reza , Malm B. Gunnar , Östling Mikael 
Published: May 2012

AbstractThe main advantage of SiC is its high critical field for breakdown. This leads to much lower on‐resistance for high voltage devices compared to silicon, but at a higher price that has to be offset by system gains. However, it is not straightforward to exploit this advantage, which is clear from the many different device types that are presently being commercialized. There are other advantages of SiC yet to be fully investigated: the possibility of high temperature operating electronics and radiation hard devices. If integrated circuits in SiC are also available, the system advantage is larger. Here temperature ranges higher than that of SOI should be aimed at, and some of these new application areas will be described. An overview of IC research will be ended with a description of our selected technology operated at 300 °C (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Discrimination of surface‐scattering mechanisms in waveguides with a rough boundary of rectangular power spectrum
Authors: Rendón M. , Makarov N. M. 
Published: May 2012

AbstractWe study transport properties of a single‐mode waveguide with rough boundary. As is known, propagating waves in such waveguides are attenuated because of two mechanisms of surface scattering: the amplitude mecha‐ nism and the square‐gradient mechanism. While the former is known since long ago, the latter was recently predicted. In general, they compete with one another and, then, it is difficult to study them individually.Here, by means of appropriate long‐range correlations specified by two correlation parameters and embedded in the disordered boundary of the waveguide, we man‐ age to separate these mechanisms and stop the competition. Specifically, we arrange different intervals of wave numbers in which they manifest themselves alone. This situation allows one to study the different nature of these scattering mechanisms. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dielectric properties of PMN+2%Li2O at low frequencies
Authors: Bormanis K. , Kalvane A. , Burkhanov A. I. , Tumanov I. E. , Mironova‐Ulmane N. 
Published: May 2012

AbstractThe reported study is focused on effects of the admixture of lithium (2% Li2O) on the low‐frequency dielectric response in lead magnesium niobate ceramics over the 100 ‐300 K range of temperature. The obtained results reveal an essential thermal broadening of the ε′(ν) spectra specific to relaxor ferroelectrics. Dispersion Δε′ = ε′1Hz‐ε′1kHz and values of ε′′(ν) in lead magnesium niobate ceramics containing Li are well described by the Cole‐Cole equation at temperatures below the ε′(T) maximum. Based on the analysis of the experimental data admixture of lithium is suggested to promote formation of domains in lead magnesium niobate ceramics (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Blanket and patterned growth of CdTe on (211)Si substrates by metal‐organic vapor phase epitaxy
Authors: Bhat Ishwara B. , Rao Sunil R. , Shintri Shashidhar , Jacobs Randolph N. 
Published: May 2012

AbstractMetalorganic vapor phase epitaxy (MOVPE) of (211)B CdTe on (211)Si using intermediate Ge and ZnTe layers has been achieved for use as substrates for the growth of HgCdTe infrared detector materials. The best (211)B CdTe films grown in this study display a low X‐ray diffraction (XRD) rocking‐curve full‐width‐at‐half‐maximum (FWHM) of 64 arcs for a 12 µm thick layer and Everson etch pit density (EPD) of 3x105cm‐2. In order to reduce the threading dislocation density further, growth on patterned layer has been investigated using Si3N4 as the mask. In order to achieve selective nucleation on patterned layer, process parameters were first developed. A circular pattern was used to study the anisotropy during growth and to identify the optimum orientation for parallel stripe growth windows. The optimum growth window was then used for the growth of completely merged layers (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Studies of surface oxidation in ultrasmall magic‐sized white‐light emitting CdSe nanocrystals using X‐ray photoelectron spectroscopy
Authors: Sohel Mohammad A. , Pan Liang , Tamargo Maria C. 
Published: May 2012

AbstractA large number of II‐VI and III‐V semiconductor nanocrystals (NCs) or quantum dots (QDs) have been studied over the years because of their size and band gap tunable optical properties, and their application in miniaturizing optoelectronic devices. Significant studies have been done in the synthesis and characterization of CdSe NCs, and their surface has been studied using X‐ray photoelectron spectroscopy (XPS). Recently, pyrolytically grown white‐light (WL) emitting ultra small, “magic size” CdSe NCs with an absorption feature at 414 nm and a broadband emission between 420 and 710 nm have been reported which show no band edge emission. Due to the extreme surface‐to‐volume ratio, the electrons and holes apparently interact on the surface producing a broad emission covering the entire visible spectrum. Due to the technological interest as white‐light phosphors for application in white light emitting diodes (LEDs), it is important to understand the surface coverage of the ligands on the surface of the CdSe NCs, and oxidation of these NCs. This paper reports the surface oxidation of these ultra‐small white‐light emitting CdSe NCs and effect of their relevant ratios of Cd and Se surface atoms as compared to regular CdSe NCs using X‐Ray Photoelectron Spectroscopy. Results shows that the degree of oxidation in the ultra small white light emitting NCs is quiet comparable to that of larger size NCs and makes it more suitable for application in optoelectronics and miniature of devices in white light emitting devices. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)