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https://www.readbyqxmd.com/read/29352258/atomic-structure-and-passivated-nature-of-the-se-treated-gaas-111-b-surface
#1
Akihiro Ohtake, Shunji Goto, Jun Nakamura
We have systematically studied the atomic structure and electronic properties of the Se-treated GaAs(111)B surface using scanning tunneling microscopy, reflection high-energy electron diffraction, x-ray photoelectron spectroscopy, and first-principles calculations. We have found that Se atoms substitute [Formula: see text] monolayer of As atoms at the outermost layer of the ideal (111)B surface. Charge transfer from Se to As eliminates all of unsaturated dangling bonds, so that the surface is electronically stabilized, leaving no surface states in the mid-gap region...
January 19, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29352141/pressure-effect-on-impurity-local-vibrational-mode-and-phase-transitions-in-n-type-iron-doped-indium-phosphide
#2
Chih-Ming Lin, I-Jui Hsu, Sin-Cheng Lin, Yu-Chun Chuang, Wei-Ting Chen, Yen-Fa Liao, Jenh-Yih Juang
The evolution of iron local vibrational mode (Fe LVM) and phase transitions in n-type iron-doped indium phosphide (InP:Fe) were investigated at ambient temperature. In-situ angle-dispersive X-ray diffraction measurements revealed that InP:Fe starts to transform from zinc-blende (ZB) to rock-salt (RS) structure around 8.2(2) GPa and completes around 16.0(2) GPa. The Raman shift of both transverse and longitudinal optical modes increases monotonically with increasing pressure, while their intensities become indiscernible at 11...
January 19, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29351882/surface-characterization-of-arsenopyrite-during-chemical-and-biological-oxidation
#3
Sha Deng, Guohua Gu, Baoke Xu, Lijuan Li, Bichao Wu
The surface properties of arsenopyrite during chemical and biological oxidation were investigated by synchrotron X-ray diffraction (S-XRD), X-ray absorption near-edge structure (XANES) and scanning electron microscope (SEM), accompanying with leaching behaviors elucidation. The moderate thermophile S. thermosulfidooxdians was used as the bioleaching microorganism. Leaching experiments showed that only 16.26% and 44.37% of total arsenic extractions were obtained for sterile acid and culture medium controls, whereas 79...
January 16, 2018: Science of the Total Environment
https://www.readbyqxmd.com/read/29351263/twenty-nine-new-limonoids-with-skeletal-diversity-from-the-mangrove-plant-xylocarpus-moluccensis
#4
Jianzhi Zhang, Wanshan Li, Yiguo Dai, Li Shen, Jun Wu
Twenty-nine new limonoids-named xylomolins A₁-A₇, B₁-B₂, C₁-C₂, D-F, G₁-G₅, H-I, J₁-J₂, K₁-K₂, L₁-L₂, and M-N, were isolated from the seeds of the mangrove plant, Xylocarpus moluccensis. Compounds 1-13 are mexicanolides with one double bond or two conjugated double bonds, while 14 belongs to a small group of mexicanolides with an oxygen bridge between C1 and C8. Compounds 15-19 are khayanolides containing a Δ8,14 double bond, whereas 20 and 21 are rare khayanolides containing a Δ14,15 double bond and Δ8,9, Δ14,15 conjugated double bonds, respectively...
January 19, 2018: Marine Drugs
https://www.readbyqxmd.com/read/29351217/nitrogen-containing-functional-groups-facilitated-acetone-adsorption-by-zif-8-derived-porous-carbon
#5
Liqing Li, Xiancheng Ma, Ruofei Chen, Chunhao Wang, Mingming Lu
Nitrogen-doped porous carbon (ZC) is prepared by modification with ammonia for increasing the specific surface area and surface polarity after carbonization of zeolite imidazole framework-8 (ZIF-8). The structure and properties of these ZCs were characterized by Transmission electron microscopy, X-ray diffraction, N₂ sorption, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Through static adsorption tests of these carbons, the sample obtained at 600 °C was selected as an excellent adsorbent, which exhibited an excellent acetone capacity of 417...
January 19, 2018: Materials
https://www.readbyqxmd.com/read/29350037/oxidation-of-isodiphenylfluorindine-routes-to-13-oxoisodiphenylfluorindinium-perchlorate-and-fluorindine-cruciform-dimers
#6
Georgia A Zissimou, Andreas Kourtellaris, Panayiotis A Koutentis
Isodiphenylfluorindine (5) reacts with K2Cr2O7/H+ to give 13-oxoisodiphenylfluorindinium perchlorate (7) (75%), but with phenyliodine bis(trifluoroacetate) (PIFA) or MnO2 it gives the zwitterionic and quinoidal cruciform 13,13'-dimers 11 (85%) and 12 (89%), respectively. The zwitterionic 13,13'-dimer 11 can be rapidly converted with MnO2 into the quinoidal 13,13'-dimer 12 (100%). UV-vis, NMR, single-crystal X-ray diffraction, and density functional theory studies support the structural assignments of all products...
January 19, 2018: Organic Letters
https://www.readbyqxmd.com/read/29350034/probing-the-complexities-of-structural-changes-in-layered-oxide-cathode-materials-for-li-ion-batteries-during-fast-charge-discharge-cycling-and-heating
#7
Enyuan Hu, Xuelong Wang, Xiqian Yu, Xiao-Qing Yang
The rechargeable lithium-ion battery (LIB) is the most promising energy storage system to power electric vehicles with high energy density and long cycling life. However, in order to meet customers' demands for fast charging, the power performances of current LIBs need to be improved. From the cathode aspect, layer-structured cathode materials are widely used in today's market and will continue to play important roles in the near future. The high rate capability of layered cathode materials during charging and discharging is critical to the power performance of the whole cell and the thermal stability is closely related to the safety issues...
January 19, 2018: Accounts of Chemical Research
https://www.readbyqxmd.com/read/29349676/environment-friendly-synthesis-of-trace-element-zn-sr-and-f-codoping-hydroxyapatite-with-non-cytotoxicity-and-improved-osteoblast-proliferation-and-differentiation
#8
Shengjie Xiao, Ming Wang, Liping Wang, Yingchun Zhu
Hydroxyapatite (HAp, Ca10[PO4]6[OH]2) doped with numerous trace elements possesses sensational biochemical effects in natural bones. To study the biochemical function of Zn, Sr, and F elements, a series of neoteric HAp biomaterials with Zn, Sr, and F concentrations close to natural bones are firstly synthesized by one-pot hydrothermal method. These materials are characterized through powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope (SEM). All the synthesized materials are HAp phase...
January 18, 2018: Biological Trace Element Research
https://www.readbyqxmd.com/read/29348430/rotator-side-chains-trigger-cooperative-transition-for-shape-and-function-memory-effect-in-organic-semiconductors
#9
Hyunjoong Chung, Dmytro Dudenko, Fengjiao Zhang, Gabriele D'Avino, Christian Ruzié, Audrey Richard, Guillaume Schweicher, Jérôme Cornil, David Beljonne, Yves Geerts, Ying Diao
Martensitic transition is a solid-state phase transition involving cooperative movement of atoms, mostly studied in metallurgy. The main characteristics are low transition barrier, ultrafast kinetics, and structural reversibility. They are rarely observed in molecular crystals, and hence the origin and mechanism are largely unexplored. Here we report the discovery of martensitic transition in single crystals of two different organic semiconductors. In situ microscopy, single-crystal X-ray diffraction, Raman and nuclear magnetic resonance spectroscopy, and molecular simulations combined indicate that the rotating bulky side chains trigger cooperative transition...
January 18, 2018: Nature Communications
https://www.readbyqxmd.com/read/29348101/effects-of-gamma-irradiation-on-the-physico-chemical-and-biological-properties-of-levofloxacin
#10
Saleem Raza, Yousaf Iqbal, Ihsan Ullah, Mohammad S Mubarak, Muhammad Usman Hameed, Muslim Raza
The aim of the present study was to examine the effect of gamma radiation on levofloxacin. Powder form of levofloxacin was subjected to different radiation doses (25, 50, 75, 100 and 125kGy) of Cobalt-60 source in a Gammacell-220 at a rate of 8.5 Gray/hr. The effect of radiation has been investigated with the aid of different spectroscopic techniques (UV-Vis, FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and by antibacterial activities. UV data did not reveal significant changes in the structure of levofloxacin which is supported by scanning electron microscopy...
January 2018: Pakistan Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/29347846/poly-butylene-adipate-co-butylene-terephthalate-nanoparticles-prepared-by-electrospraying-technique-for-docetaxel-delivery-in-ovarian-cancer-induced-mice
#11
Jaleh Varshosaz, Erfaneh Ghassami, Abdollah Noorbakhsh, Ali Jahanian-Najafabadi, Mohsen Minaiyan, Ramezan Behzadi
OBJECTIVES: Ovarian cancer is still a major cause of morbidity and mortality. Docetaxel (DTX) is one of the most notable cytotoxic agents for treatment of ovarian cancer. However, its side-effects proposed considerable problems to the patients. SIGNIFICANCE: Polymeric nanoparticles (NPs) of poly (butylene adipate-co-butylene terephthalate) (Ecoflex®), a biodegradable and biocompatible polymer, were prepared for the first time by the upgradeable electrospraying technique...
January 18, 2018: Drug Development and Industrial Pharmacy
https://www.readbyqxmd.com/read/29347717/crossover-between-liquidlike-and-gaslike-behavior-in-ch_-4-at-400-k
#12
D Smith, M A Hakeem, P Parisiades, H E Maynard-Casely, D Foster, D Eden, D J Bull, A R L Marshall, A M Adawi, R Howie, A Sapelkin, V V Brazhkin, J E Proctor
We report experimental evidence for a crossover between a liquidlike state and a gaslike state in fluid methane (CH_{4}). This crossover is observed in all of our experiments, up to a temperature of 397 K, 2.1 times the critical temperature of methane. The crossover has been characterized with both Raman spectroscopy and x-ray diffraction in a number of separate experiments, and confirmed to be reversible. We associate this crossover with the Frenkel line-a recently hypothesized crossover in dynamic properties of fluids extending to arbitrarily high pressure and temperature, dividing the phase diagram into separate regions where the fluid possesses liquidlike and gaslike properties...
November 2017: Physical Review. E
https://www.readbyqxmd.com/read/29347136/linking-initial-microstructure-and-local-response-during-quasistatic-granular-compaction
#13
R C Hurley, J Lind, D C Pagan, M A Homel, M C Akin, E B Herbold
We performed experiments combining three-dimensional x-ray diffraction and x-ray computed tomography to explore the relationship between microstructure and local force and strain during quasistatic granular compaction. We found that initial void space around a grain and contact coordination number before compaction can be used to predict regions vulnerable to above-average local force and strain at later stages of compaction. We also found correlations between void space around a grain and coordination number, and between grain stress and maximum interparticle force, at all stages of compaction...
July 2017: Physical Review. E
https://www.readbyqxmd.com/read/29346728/design-and-assembly-of-chiral-coordination-cages-for-asymmetric-sequential-reactions
#14
Jingjing Jiao, Chunxia Tan, Zijian Li, Yan Liu, Xing Han, Yong Cui
Supramolecular nanoreactors featuring multiple catalytically active sites are of great importance, especially for asymmetric catalysis, are yet challenging to construct. Here we report the design and assembly of five chiral single- and mixed-linker tetrahedral coordination cages using six dicarboxylate ligands derived-from enantiopure Mn(salen), Cr(salen) and/or Fe(salen) as linear linkers and four Cp3Zr3 clusters as three-connected vertices. The formation of these cages was confirmed by a variety of techniques including single-crystal and powder X-ray diffraction, inductively coupled plasma optical emission spectrometer, quadrupole-time of flight mass spectrometry and energy dispersive X-ray spectrometry...
January 18, 2018: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/29346306/zinc-tantalum-oxynitride-zntao%C3%A2-n-photoanode-modified-with-cobalt-phosphate-layers-for-the-photoelectrochemical-oxidation-of-alkali-water
#15
Prabhakarn Arunachalam, Maged N Shaddad, Mohamed A Ghanem, Abdullah M Al-Mayouf, Mark T Weller
Photoanodes fabricated by the electrophoretic deposition of a thermally prepared zinc tantalum oxynitride (ZnTaO₂N) catalyst onto indium tin oxide (ITO) substrates show photoactivation for the oxygen evolution reaction (OER) in alkaline solutions. The photoactivity of the OER is further boosted by the photodeposition of cobalt phosphate (CoPi) layers onto the surface of the ZnTaO₂N photoanodes. Structural, morphological, and photoelectrochemical (PEC) properties of the modified ZnTaO₂N photoanodes are studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet visible (UV-Vis) diffuse reflectance spectroscopy, and electrochemical techniques...
January 18, 2018: Nanomaterials
https://www.readbyqxmd.com/read/29345956/measuring-three-dimensional-strain-and-structural-defects-in-a-single-ingaas-nanowire-using-coherent-x-ray-multi-angle-bragg-projection-ptychography
#16
Megan O Hill, Irene Calvo-Almazan, Mark Allain, Martin Holt, Andrew Ulvestad, Julian Treu, Gregor Koblmueller, Chunyi Huang, Xiaojing Huang, Hanfei Yan, E Nazarestski, Yong S Chu, G Brian Stephenson, Virginie Chamard, Lincoln Lauhon, Stephan O Hruszkewycz
III-As nanowires are candidates for near infrared light emitters and detectors that can be directly integrated onto silicon. However, nanoscale to microscale variations in structure, composition, and strain within a given nanowire, as well as variations between nanowires, pose challenges to correlating microstructure with device performance. In this work, we utilize coherent nano-focused x-rays to characterize stacking defects and strain in a single InGaAs nanowire supported on Si. By reconstructing diffraction patterns from the 2-1-10 Bragg peak, we show that the lattice orientation varies along the length of the wire, while the strain field along the cross-section is largely unaffected, leaving the band structure unperturbed...
January 18, 2018: Nano Letters
https://www.readbyqxmd.com/read/29345708/triphenylstannyl-arylimino-methyl-benzoates-with-selective-potency-that-induce-g1-and-g2-m-cell-cycle-arrest-and-trigger-apoptosis-via-ros-in-human-cervical-cancer-cells
#17
Tushar S Basu Baul, Imliwati Longkumer, Andrew Duthie, Priya Singh, Biplob Koch, M Fátima C Guedes da Silva
Metal complexes with organelle specificity and potent but selective cytotoxicity are highly desirable. A novel series of triphenylstannyl 4-((arylimino)methyl)benzoates (2-8) were obtained by the reactions of triphenylstannyl 4-formylbenzoate [Ph3Sn(L1)] 1 with primary aromatic amines. Two representative compounds (10, 11) were also synthesized by reacting aqua-triphenylstannyl 2-formylbenzoate [Ph3Sn(L9)(H2O)] (9) with aniline and p-fluoroaniline, respectively. These compounds were characterized by elemental analysis, IR and 1H, 13C and 119Sn NMR spectroscopy, as well as single-crystal X-ray diffraction for compounds 5, 7-11 and three pro-ligands...
January 18, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29345459/bifunctional-hybrid-catalysts-with-perovskite-laco0-8fe0-2o3-nanowires-and-reduced-graphene-oxide-sheets-for-an-efficient-li-o2-battery-cathode
#18
Jong Guk Kim, Youngmin Kim, Yuseong Noh, Seonhwa Lee, Yoongon Kim, Won Bae Kim
In this paper, bifunctional catalysts consisting of perovskite LaCo0.8Fe0.2O3 nanowires (LCFO NWs) with reduced graphene oxide (rGO) sheets were prepared for use in lithium-oxygen (Li-O2) battery cathodes. The structure and morphology of bifunctional LCFO@rGO catalysts were characterized by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The prepared LCFO@rGO composite was explored as a cathode catalyst for Li-O2 batteries, resulted in an outstanding discharge capacity (ca...
January 18, 2018: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29345384/a-single-molecule-propyne-trap-highly-efficient-removal-of-propyne-from-propylene-with-anion-pillared-ultramicroporous-materials
#19
Lifeng Yang, Xili Cui, Qiwei Yang, Siheng Qian, Hui Wu, Zongbi Bao, Zhiguo Zhang, Qilong Ren, Wei Zhou, Banglin Chen, Huabin Xing
Propyne/propylene (C3 H4 /C3 H6 ) separation is a critical process for the production of polymer-grade C3 H6 . However, optimization of the structure of porous materials for the highly efficient removal of C3 H4 from C3 H6 remains challenging due to their similar structures and ultralow C3 H4 concentration. Here, it is first reported that hybrid ultramicroporous materials with pillared inorganic anions (SiF62- = SIFSIX, NbOF52- = NbOFFIVE) can serve as highly selective C3 H4 traps for the removal of trace C3 H4 from C3 H6 ...
January 18, 2018: Advanced Materials
https://www.readbyqxmd.com/read/29345272/preparation-of-eu-iii-acetylacetonate-doped-well-defined-titania-particles-with-efficient-photoluminescence-properties
#20
Kota Shiba, Takuya Kataoka, Motohiro Tagaya
The aggregation/dispersion of luminescent species is a critical factor that determines their luminescence properties. In this study, europium(iii) acetylacetonate (Eu(acac)3) was doped into a titania matrix to form Eu(acac)3-doped titania particles with well-defined size and shape through a microreactor-based sol-gel approach. The morphology and structure of the as-synthesized products were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, scanning transmission electron microscopy and X-ray diffraction measurements...
January 18, 2018: Dalton Transactions: An International Journal of Inorganic Chemistry
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