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https://www.readbyqxmd.com/read/28933548/investigation-of-structure-and-crystallization-behavior-of-poly-butylene-succinate-by-fourier-transform-infrared-spectroscopy
#1
Shu-Fang Yao, Xiao-Tong Chen, Hai-Mu Ye
The detailed structure and crystallization behavior of poly(butylene succinate) (PBS) have been investigated by Fourier transform infrared (FTIR) and other methods systematically. For the first time, we confirmed that the C=O stretching modes of PBS can respond to three distinguish absorption bands in the FTIR spectrum, at around 1736, 1720 and 1714 cm-1 respectively. The 1736 cm-1 band is adopted as the stretching mode of C=O groups in free amorphous fraction (MAF); the 1714 cm-1 band which is relevant to more stable structure, displays more anisotropic in polarized FTIR spectra, and has been confirmed as stretching vibrations of hydrogen-bonded C=O groups in the crystalline phase...
September 21, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28932847/dichotomy-between-the-band-and-hopping-transport-in-organic-crystals-insights-from-experiments
#2
I Yavuz
The molecular understanding of charge-transport in organic crystals has often been tangled with identifying the true dynamical origin. While in two distinct cases where complete delocalization and localization of charge-carriers are associated with band-like and hopping-like transports, respectively, their possible coalescence poses some mystery. Moreover, the existing models are still controversial at ambient temperatures. Here, we review the issues in charge-transport theories of organic materials and then provide an overview of prominent transport models...
September 21, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28925923/diverse-carrier-mobility-of-monolayer-bnc-sub-x-sub-a-combined-density-functional-theory-and-boltzmann-transport-theory-study
#3
Tao Wu, Kaiming Deng, Wei-Qiao Deng, Ruifeng Lu
BNCX monolayer as a kind of two-dimensional material has numerous chemical atomic ratios and arrangements with different electronic structures. Via calculations on the basis of density functional theory and Boltzmann transport theory under deformation potential approximation, the band structures and carrier mobilities of BNCX (x=1,2,3,4) nanosheets are systematically investigated. The calculated results show that BNC2-1 is a material with very small band gap (0.02 eV) among all the structures while other BNCX monolayers are semiconductors with band gap ranging from 0...
September 19, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28925264/space-environment-effects-on-flexible-low-voltage-organic-thin-film-transistors
#4
Laura Basiricò, Alberto Francesco Basile, Piero Cosseddu, Simone Gerardin, Tobias Cramer, Marta Bagatin, Andrea Ciavatti, Alessandro Paccagnella, Annalisa Bonfiglio, Beatrice Fraboni
Organic electronic devices fabricated on flexible substrates are promising candidates for applications in environments where flexible, light-weight and radiation hard materials are required. In this work, device parameters as threshold voltage, charge mobility and trap density of 13-Bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) based OTFTs have been monitored performing electrical measurements before and after irradiation by high-energy protons. The observed reduction of charge carrier mobility following irradiation can be only partially ascribed to the increased trap density...
September 19, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28923974/manipulation-of-ionized-impurity-scattering-for-achieving-high-thermoelectric-performance-in-n-type-mg3sb2-based-materials
#5
Jun Mao, Jing Shuai, Shaowei Song, Yixuan Wu, Rebecca Dally, Jiawei Zhou, Zihang Liu, Jifeng Sun, Qinyong Zhang, Clarina Dela Cruz, Stephen Wilson, Yanzhong Pei, David J Singh, Gang Chen, Ching-Wu Chu, Zhifeng Ren
Achieving higher carrier mobility plays a pivotal role for obtaining potentially high thermoelectric performance. In principle, the carrier mobility is governed by the band structure as well as by the carrier scattering mechanism. Here, we demonstrate that by manipulating the carrier scattering mechanism in n-type Mg3Sb2-based materials, a substantial improvement in carrier mobility, and hence the power factor, can be achieved. In this work, Fe, Co, Hf, and Ta are doped on the Mg site of Mg3.2Sb1.5Bi0.49Te0...
September 18, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28923418/active-modulation-in-neat-carbon-dioxide-packed-column-comprehensive-two-dimensional-supercritical-fluid-chromatography
#6
Orjen Petkovic, Pierre Guibal, Patrick Sassiat, Jérôme Vial, Didier Thiébaut
After demonstrating in a first paper the feasibility of SFCxSFC without decompression of the mobile phase, a modified interface has been developed in order to perform active modulation between the two SFC dimensions. In this paper, it is shown that the new interface enabled independent control of modulation parameters in SFCxSFC and performed a band compression effect of solutes between the two SFC dimensions. The effectiveness of this new modulation process was studied using a Design of Experiments. The SFCxSFC prototype was applied to the analysis of a real oil sample to demonstrate the benefits of the active modulator; in comparison to our previous results obtained without active modulation, better separation was obtained with the new interface owing to the peak compression occurring in the modulator...
August 26, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28917757/innovative-thin-layer-chromatographic-method-combined-with-fluorescence-detection-for-specific-determination-of-febuxostat-application-in-biological-fluids
#7
Abdel-Maaboud I Mohamed, Mahmoud A Omar, Sayed M Derayea, Mohamed A Hammad, Abobakr A Mohamed
A newly developed thin-layer chromatographic (TLC) method coupled with fluorescence detection for specific determination of Febuxostat (FEB) was designed. The proposed method adopts exposure of FEB on a developed TLC plate to hydrochloric acid vapors, resulting in a large enhancement of its weak fluorescence, permitting its specific and sensitive determination in real human plasma and urine after excitation at 345nm on 60 F254 silica gel plates using toluene-ethyl acetate-methanol-glacial acetic acid; (30:10:5:0...
January 1, 2018: Talanta
https://www.readbyqxmd.com/read/28913649/improvement-in-diagnostic-and-therapeutic-arthrocentesis-via-constant-compression
#8
Tej B Bhavsar, Wilmer L Sibbitt, Philip A Band, Romy J Cabacungan, Timothy S Moore, Luis C Salayandia, Roderick A Fields, Scarlett K Kettwich, Luis P Roldan, N Suzanne Emil, Monthida Fangtham, Arthur D Bankhurst
We hypothesized that constant compression of the knee would mobilize residual synovial fluid and promote successful arthrocentesis. Two hundred and ten knees with grade II-III osteoarthritis were included in this paired design study: (1) conventional arthrocentesis was performed with manual compression and success and volume (milliliters) determined; and (2) the intra-articular needle was left in place, and a circumferential elastomeric brace was tightened on the knee to provide constant compression. Arthrocentesis was attempted again and additional fluid volume was determined...
September 14, 2017: Clinical Rheumatology
https://www.readbyqxmd.com/read/28913429/ultrahigh-mobility-and-efficient-charge-injection-in-monolayer-organic-thin-film-transistors-on-boron-nitride
#9
Daowei He, Jingsi Qiao, Linglong Zhang, Junya Wang, Tu Lan, Jun Qian, Yun Li, Yi Shi, Yang Chai, Wei Lan, Luis K Ono, Yabing Qi, Jian-Bin Xu, Wei Ji, Xinran Wang
Organic thin-film transistors (OTFTs) with high mobility and low contact resistance have been actively pursued as building blocks for low-cost organic electronics. In conventional solution-processed or vacuum-deposited OTFTs, due to interfacial defects and traps, the organic film has to reach a certain thickness for efficient charge transport. Using an ultimate monolayer of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) molecules as an OTFT channel, we demonstrate remarkable electrical characteristics, including intrinsic hole mobility over 30 cm(2)/Vs, Ohmic contact with 100 Ω · cm resistance, and band-like transport down to 150 K...
September 2017: Science Advances
https://www.readbyqxmd.com/read/28903833/resolution-and-quantitation-of-triamcinolone-acetonide-and-its-coformulated-drug-in-the-presence-of-its-impurities-and-degradation-products-by-hptlc-and-hplc
#10
Samah S Abbas, Maha A Hegazy, Hassan A M Hendawy, Soheir A Weshahy, May H Abdelwahab
Two specific, sensitive, and precise stability-indicating chromatographic methods have been developed for thedetermination of triamcinolone acetonide (TMC) and its coformulated drug, econazole nitrate (ECZ), in the presence of TMC impurities and degradation products. The first method was based on HPTLC-spectrodensitometry in which resolution and quantitation was achieved by using silica gel 60 F254 HPTLC plates and an ethyl acetate–tetrahydrofuran–ammonia mobile phase (10.0 + 7.0 + 0.1, v/v/v)...
September 14, 2017: Journal of AOAC International
https://www.readbyqxmd.com/read/28900645/role-of-intermolecular-charge-delocalization-and-its-dimensionality-in-efficient-band-like-electron-transport-in-crystalline-2-5-difluoro-7-7-8-8-tetracyanoquinodimethane-f2-tcnq
#11
Andrey Yu Sosorev
Theoretical understanding of charge transport in organic semiconductors is exclusively important for organic electronics, but still remains a subject of debate. The recently discovered record-high band-like electron mobility in single crystals of 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane (F2-TCNQ) is challenging from the theoretical viewpoint. First, the very small size of the F2-TCNQ molecule implies high reorganization energy that seems incompatible with efficient charge transport. Second, it is not clear why the crystals of a similar compound, 7,7,8,8-tetracyanoquinodimethane (TCNQ), show an inefficient hopping electron transport mechanism...
September 13, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28895967/scavenging-activity-of-magn%C3%A3-li-phases-as-a-function-of-ti-4-ti-3-ratios
#12
M Canillas, E Chinarro, A P Pêgo, B Moreno
TiO2 is able to scavenge reactive oxygen and nitrogen species (ROS and RNS) in the absence of light. The scavenging mechanism has been related to the chemistry of defects (oxygen vacancy reduced oxidation states of Ti) but it is still unknown. This study describes the ROS scavenging activity of different titanium oxide phases and relates their scavenging activities with the Ti(4+)/Ti(3+) molar ratio as well as the band gap value. The Ti5O9 phase, with a mixture of both oxidation states, presented a substantially higher percentage of 2,2-diphenyl-1-picrylhydracyl radicals (DPPH˙) eliminated per m(2) of specific surface area in comparison to phases with predominant oxidation states Ti(4+) or Ti(3+) such as TiO2 and Ti2O3, respectively...
September 21, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28895395/thermoelectric-properties-of-sns-with-na-doping
#13
Binqiang Zhou, Shuai Li, Wen Li, Juan Li, Xinyue Zhang, Siqi Lin, Zhiwei Chen, Yanzhong Pei
Tin sulfide (SnS), a low-cost compound from the IV-VI semiconductors, has attracted particular attention due to its great potential for large-scale thermoelectric applications. However, pristine SnS shows a low carrier concentration, which leads to a low thermoelectric performance. In this work, sodium is utilized to substitute Sn to increase the hole concentration and consequently improve the thermoelectric power factor. The resultant Hall carrier concentration up to ∼10(19) cm(-3) is the highest concentration reported so far for this compound...
September 19, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28889743/prediction-of-green-phosphorus-with-tunable-direct-band-gap-and-high-mobility
#14
Woo Hyun Han, Sunghyun Kim, In-Ho Lee, Kee Joo Chang
Black phosphorus is an emerging material in nanoelectronics and nanophotonics due to its high carrier mobility and anisotropic in-plane properties. In addition, the polymorphism of phosphorus leads to numerous searches for new allotropes that are more attractive than black phosphorus in a variety of applications. On the basis of ab initio evolutionary crystal structure search computation, we report the prediction of a phosphorus allotrope called green phosphorus (λ-P), which exhibits direct band gaps ranging from 0...
September 13, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28884850/regioregular-phthalocyanines-substituted-with-bulky-donors-at-non-peripheral-positions
#15
Satoshi Yamamoto, Kengo Kuribayashi, Takuro N Murakami, Eunsang Kwon, Martin J Stillman, Nagao Kobayashi, Hiroshi Segawa, Mutsumi Kimura
Three regioregular phthalocyanines (1-3) were synthesized selectively by the cyclic tetramerization of phthalonitriles bearing a bulky diarylamine substituent at the next position of nitrile. The steric repulsion at the tetramerization of bulky phthalonitriles allowed for the selective formation of regioregular phthalocyanines as confirmed by NMR and single crystal X-ray structural analyses. The absorption spectrum of 1 substituted with di(4-tert-buthylphenyl)amine groups at the non-peripheral positions showed a non-split Q band at 764 nm, which was red-shifted by 83 nm compared with that of metal free phthalocyanine (H2Pc)...
September 8, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28879862/improved-charge-separation-efficiency-of-hematite-photoanodes-by-coating-an-ultrathin-p-type-lafeo3-overlayer
#16
Tao Fang, Yongsheng Guo, Songhua Cai, Ningsi Zhang, Yingfei Hu, Shiying Zhang, Zhaosheng Li, Zhigang Zou
Many metal-oxide candidates for photoelectrochemical water splitting exhibit localized small polaron carrier conduction. Especially hematite (α-Fe2O3) photoanodes often suffer from low carrier mobility, which causes the serious bulk electron-hole recombination and greatly limits their PEC performances. In this study, the charge separation efficiency of hematite was enhanced greatly by coating an ultrathin p-type LaFeO3 overlayer. Compared to the hematite photoanodes, the solar water splitting photocurrent of the Fe2O3/LaFeO3 n-p junction exhibits a 90% increase at 1...
September 7, 2017: Nanotechnology
https://www.readbyqxmd.com/read/28874050/thermal-gradient-mid-and-far-infrared-spectroscopy-as-tools-for-characterization-of-protein-sugar-lyophilizates
#17
M A Mensink, J Šibík, H W Frijlink, K van der Voort Maarschalk, W L J Hinrichs, J A Zeitler
Protein drugs play an important role in modern day medicine. Typically, these proteins are formulated as liquids requiring cold chain processing. To circumvent the cold chain and achieve better storage stability, these proteins can be dried in the presence of sugars. We demonstrate that thermal gradient mid and far infrared spectroscopy (FTIR and THz-TDS, respectively) can provide useful information about solid-state protein sugar formulations regarding mobility and intermolecular interactions. A model protein (BSA) was lyophilized in the presence of three sugars with different size and protein stabilizing capacity...
September 5, 2017: Molecular Pharmaceutics
https://www.readbyqxmd.com/read/28873310/vertical-inas-ingaas-heterostructure-mosfets-on-si
#18
Olli-Pekka Kilpi, Johannes Svensson, Jun Wu, Axel R Persson, Lars Reine Wallenberg, Erik Lind, Lars-Erik Wernersson
III-V compound semiconductors offers a path to continue Moore's law due to the excellent electron transport properties. One major challenge, integrating III-Vs on Si, can be addressed by using vapor-liquid-solid grown vertical nanowires. InAs is an attractive material due to its superior mobility, although InAs MOSFETs typically suffer from band-to-band tunneling caused by its narrow band-gap, which increases the off-current and therefore the power consumption. In this work, we present vertical heterostructure InAs/InGaAs nanowire MOSFETs with low off-currents provided by the wider band-gap material on the drain side suppressing band-to-band tunneling...
September 5, 2017: Nano Letters
https://www.readbyqxmd.com/read/28873294/pdse2-pentagonal-2d-layers-with-high-air-stability-for-electronics
#19
Akinola Oyedele, Shi-Ze Yang, Liangbo Liang, Alexander Puretzky, Kai Wang, Jingjie Zhang, Peng Yu, Pushpa Pudasaini, Avik W Ghosh, Zheng Liu, Christopher M Rouleau, Bobby G Sumpter, Matthew F Chisholm, Wu Zhou, Philip D Rack, David Geohegan, Kai Xiao
Most studied two-dimensional (2D) materials exhibit isotropic behavior due to high lattice symmetry; however, lower-symmetry 2D materials such as phosphorene and other elemental 2D materials exhibit very interesting anisotropic properties. In this work, we report the atomic structure, electronic properties, and vibrational modes of few-layered PdSe2, exfoliated from bulk crystals, a pentagonal 2D layered noble transition metal dichalcogenide with a puckered morphology that is air-stable. Micro-absorption optical spectroscopy and first-principles calculations reveal a wide band gap variation in this material from ~0 (bulk) to ~1...
September 5, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28872182/quantum-dots-in-photocatalytic-applications-efficiently-enhancing-visible-light-photocatalytic-activity-by-integrating-cdo-quantum-dots-as-sensitizers
#20
A H Reshak
The amalgamation of a wide optical band gap photocatalyst with visible-light-active CdO quantum dots (QDs) as sensitizers is one of the most efficient ways to improve photocatalytic performance under visible light irradiation. The photocatalytic performance of cadmium benzoate ((Cd(C7H5O2)2)3(CH3CN)1) is comprehensively investigated. The estimated optical band gap of cadmium benzoate is 2.64 eV and the EPc and EPv are about -0.09 V (vs. NHE) and +2.55 V (vs. NHE), respectively, which implies that cadmium benzoate possesses a high negative reduction potential of excited electrons due to its higher conduction band position, and hence, the locations of the conduction band minimum and the valence band maximum meet the redox capacity...
September 20, 2017: Physical Chemistry Chemical Physics: PCCP
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