bluuebunny/crossref_metadata_2025 huggingface dataset:
Catalytic selectivity of Rh/TiO2catalyst in syngas conversion to ethanol: probing into the mechanism and functions of TiO2support and promoter
Authors: Zhang Riguang , Peng Mao , Wang Baojun
Published: January 2017

The catalytic selectivity, the functions of a TiO2support and promoter, and the mechanism of ethanol synthesis from syngas on a Rh/TiO2model catalyst have been fully identified.
Design of a flexible organometallic tecton: host–guest chemistry with picric acid and self-assembly of platinum macrocycles
Authors: Jana Achintya , Bhowmick Sourav , Kaur Supreet , Kashyap Hemant K. , Das Neeladri
Published: January 2017

A new “flexible” and ditopic Pt(ii) organometallic compound is a tecton for the self-assembly of neutral metallacycles. It also exhibits significant binding affinity for picric acid.
Freeze-dried MoS2 sponge electrodes for enhanced electrochemical energy storage
Authors: Balasingam Suresh Kannan , Lee Minoh , Kim Byung Hoon , Lee Jae Sung , Jun Yongseok
Published: January 2017

High surface area MoS2 sponge electrodes were synthesized via a facile hydrothermal method followed by a freeze drying process and showed high specific capacitance and better charge storage behavior.
Synergetic effect in heterogeneous acid catalysis by a porous ionic crystal based on Al(iii)–salphen and polyoxometalate
Authors: Kawahara Ryosuke , Osuga Ryota , Kondo Junko N. , Mizuno Noritaka , Uchida Sayaka
Published: January 2017

A porous ionic crystal with Al(salphen) and polyoxometalate shows high activity as a heterogeneous catalyst, while the components are much less active, suggesting a synergetic effect.
Highly efficient perovskite solar cells with a compositionally engineered perovskite/hole transporting material interface
Authors: Cho Kyung Taek , Paek Sanghyun , Grancini Giulia , Roldán-Carmona Cristina , Gao Peng , Lee Yonghui , Nazeeruddin Mohammad Khaja
Published: January 2017

We demonstrate reduced charge recombination by formation of an engineered passivating layer, which leads to an enhanced power conversion efficiency of 21%.
Texturing in situ: N,S-enriched hierarchically porous carbon as a highly active reversible oxygen electrocatalyst
Authors: Pei Zengxia , Li Hongfei , Huang Yan , Xue Qi , Huang Yang , Zhu Minshen , Wang Zifeng , Zhi Chunyi
Published: January 2017

An in situ texturing protocol is developed for preparing N,S-enriched hierarchically porous carbon as an excellent reversible oxygen electrocatalyst.
Engineering stepped edge surface structures of MoS2sheet stacks to accelerate the hydrogen evolution reaction
Authors: Hu Jue , Huang Bolong , Zhang Chengxu , Wang Zilong , An Yiming , Zhou Dan , Lin He , Leung Michael K. H. , Yang Shihe
Published: January 2017

Significantly enhanced HER kinetics were achieved by controllably fabricating a stepped MoS2surface structure which possesses more optimal free energy of H-adsorption.
Microbial distribution and variation in produced water from separators to storage tanks of shale gas wells in Sichuan Basin, China
Authors: Zhang Yimeng , Yu Zhisheng , Zhang Hongxun , Thompson Ian P.
Published: January 2017

Production facilities harbor diverse microorganisms including sulfidogenic bacteria, acid producers and fermenters, showing the potential need for effective microbial control during the production of shale gas.
Maximizing Coulombic recovery and solids reduction from primary sludge by controlling retention time and pH in a flat-plate microbial electrolysis cell
Authors: Ki Dongwon , Parameswaran Prathap , Popat Sudeep C. , Rittmann Bruce E. , Torres César I.
Published: January 2017

Control of hydraulic retention time and pH of the anode chamber in a flat-plate microbial electrolysis cell can improve Coulombic recovery and sludge stabilization.
Boundary layer friction of solvate ionic liquids as a function of potential
Authors: Li Hua , Rutland Mark W. , Watanabe Masayoshi , Atkin Rob
Published: January 2017

Atomic force microscopy (AFM) has been used to investigate the potential dependent boundary layer friction at solvate ionic liquid (SIL)–highly ordered pyrolytic graphite (HOPG) and SIL–Au(111) interfaces. Friction trace and retrace loops of lithium tetraglyme bis(trifluoromethylsulfonyl)amide (Li(G4) TFSI) at HOPG present clearer stick-slip events at negative potentials than at positive potentials, indicating that a Li+ cation layer adsorbed to the HOPG lattice at negative potentials which enhances stick-slip events. The boundary layer friction data for Li(G4) TFSI shows that at HOPG, friction forces at all potentials are low. The TFSI− anion rich boundary layer at positive potentials is more lubricating than the Li+ cation rich boundary layer at negative potentials. These results suggest that boundary layers at all potentials are smooth and energy is predominantly dissipated via stick-slip events. In contrast, friction at Au(111) for Li(G4) TFSI is significantly higher at positive potentials than at negative potentials, which is comparable to that at HOPG at the same potential. The similarity of boundary layer friction at negatively charged HOPG and Au(111) surfaces indicates that the boundary layer compositions are similar and rich in Li+ cations for both surfaces at negative potentials. However, at Au(111), the TFSI− rich boundary layer is less lubricating than the Li+ rich boundary layer, which implies that anion reorientations rather than stick-slip events are the predominant energy dissipation pathways. This is confirmed by the boundary friction of Li(G4) NO3 at Au(111), which shows similar friction to Li(G4) TFSI at negative potentials due to the same cation rich boundary layer composition, but even higher friction at positive potentials, due to higher energy dissipation in the NO3− rich boundary layer.
The anti-obesity effect of fermented barley extracts with Lactobacillus plantarum dy-1 and Saccharomyces cerevisiae in diet-induced obese rats
Authors: Zhang Jiayan , Xiao Xiang , Dong Ying , Shi Lani , Xu Tian , Wu Fei
Published: January 2017

Fermented cereals have significant potential for improving the nutritional quality and health effects of foods and ingredients.
Investigation into the bioavailability of milk protein-derived peptides with dipeptidyl-peptidase IV inhibitory activity using Caco-2 cell monolayers
Authors: Lacroix Isabelle M. E. , Chen Xiu-Min , Kitts David D. , Li-Chan Eunice C. Y.
Published: January 2017

The present study used Caco-2 cell monolayers to investigate the bioavailability of milk protein-derived peptides with DPP-IV inhibitory activity and showed that the susceptibility of the peptides to brush border membrane peptidases impacts their biological activity.
Modulation of gut microbiota and increase in fecal water content in mice induced by administration of Lactobacillus kefiranofaciens DN1
Authors: Jeong Dana , Kim Dong-Hyeon , Kang Il-Byeong , Kim Hyunsook , Song Kwang-Young , Kim Hong-Seok , Seo Kun-Ho
Published: January 2017

Effects of oral consumption ofL. kefiranofacienson the fecal quality and intestinal microbiota of mice.
Highly efficient synthesis of 2-mercaptobenzothiazole derivatives in water: metal sulfide–disulfide dynamic interchange reaction
Authors: Lou Chunqing , Zhu Ning , Fan Ronghua , Hong Hailong , Han Limin , Zhang Jianbin , Suo Quanling
Published: January 2017

A convenient and efficient method for the synthesis of 2-mercaptobenzothiazoles from disulfide and CS2 was performed by dynamic interchange reaction between a disulfide and a metal sulfide in water.
Development of a concise, scalable synthesis of a CCR1 antagonist utilizing a continuous flow Curtius rearrangement
Authors: Marsini Maurice A. , Buono Frederic G. , Lorenz Jon C. , Yang Bing-Shiou , Reeves Jonathan T. , Sidhu Kanwar , Sarvestani Max , Tan Zhulin , Zhang Yongda , Li Ning , Lee Heewon , Brazzillo Jason , Nummy Laurence J. , Chung J. C. , Luvaga Irungu K. , Narayanan Bikshandarkoil A. , Wei Xudong , Song Jinhua J. , Roschangar Frank , Yee Nathan K. , Senanayake Chris H.
Published: January 2017

A convergent and robust synthesis of a developmental CCR1 antagonist is described using continuous flow technology.
An amorphous Cu–In–S nanoparticle-based precursor ink with improved atom economy for CuInSe2 solar cells with 10.85% efficiency
Authors: Ahn SeJin , Rehan Shanza , Moon Dong Gwon , Eo Young-Joo , Ahn SeungKyu , Yun Jae Ho , Cho Ara , Gwak Jihye
Published: January 2017

Even with low-quality precursors (amorphous Cu–In–S nanoparticles), improved atom economy in the inks enables the fabrication of highly-performing devices.
Correlation of focal adhesion assembly and disassembly with cell migration on nanotopography
Authors: Liang Elena I. , Mah Emma J. , Yee Albert F. , Digman Michelle A.
Published: January 2017

We provide a dynamic perspective of how nanotopography regulate adhesions at the single molecular level.
Crossed flow microfluidics for high throughput screening of bioactive chemical–cell interactions
Authors: Tong Ziqiu , Ivask Angela , Guo Keying , McCormick Scott , Lombi Enzo , Priest Craig , Voelcker Nicolas H.
Published: January 2017

A crossed flow microfluidic device was used for generation of cell-based arrays aiming for high throughput screening of applied bioactive chemicals to captured cells.
Novel bivalent securinine mimetics as topoisomerase I inhibitors
Authors: Hou Wen , Lin Hui , Wang Zhen-Ya , Banwell Martin G. , Zeng Ting , Sun Ping-Hua , Lin Jing , Chen Wei-Min
Published: January 2017

A series of novel bivalent securinine mimetics incorporating different linkers between C-15 and C-15′ were synthesized and their topoisomerase I (Topo I) inhibitory activities evaluated.
Improving photoanodes to obtain highly efficient dye-sensitized solar cells: a brief review
Authors: Fan Ke , Yu Jiaguo , Ho Wingkei
Published: January 2017

This review highlights the last two decades' efforts towards producing highly efficient dye-sensitized solar cells by improving the photoanodes.
Directional elastic wave propagation in high-aspect-ratio photoresist gratings: liquid infiltration and aging
Authors: Alonso-Redondo E. , Gueddida A. , Li J. , Graczykowski B. , Sotomayor Torres C. M. , Pennec Y. , Yang S. , Djafari-Rouhani B. , Fytas G.
Published: January 2017

Directional elastic wave propagation in high-aspect-ratio photoresist gratings is assessed by Brillouin spectroscopy in two cases: liquid infiltration and aging.
New compounds from a hydrothermal vent crab-associated fungus Aspergillus versicolor XZ-4
Authors: Pan Chengqian , Shi Yutong , Chen Xuegang , Chen Chen-Tung Arthur , Tao Xinyi , Wu Bin
Published: January 2017

Three new quinazoline derivatives (1–3), one new oxepin-containing natural product (4) and four new cyclopenin derivatives (5–7 and 9) have been isolated from an EtOAc extract of the Taiwan Kueishantao hydrothermal vent crab-associated fungus Aspergillus versicolor XZ-4.
Cononsolvency in the ‘drunken’ state: the thermoresponsiveness of a new acrylamide copolymer in water–alcohol mixtures
Authors: Lucht Niklas , Eggers Steffen , Abetz Volker
Published: January 2017

This work presents the synthesis and thermoresponsiveness of a random acrylamide copolymer in alcohol–water mixtures and discusses cononsolvency phenomena.
Hyperbranched poly(glycerol) as a T1 contrast agent for tumor-targeted magnetic resonance imaging in vivo
Authors: Cao Yi , Liu Min , Zu Guangyue , Kuang Ye , Tong Xiaoyan , Xiong Dangsheng , Pei Renjun
Published: January 2017

To explore a convenient and efficient strategy for constructing tumor-targeted T1 mCAs for MRI, hyperbranched poly(glycerol) prepared in one-pot was used to conjugate gadolinium chelates and folic acid ligands through “click chemistry”.
Semiconducting alternating multi-block copolymers via a di-functionalized macromonomer approach
Authors: Gasperini A. , Johnson M. , Jeanbourquin X. , Yao L. , Rahmanudin A. , Guijarro N. , Sivula K.
Published: January 2017

A route to fully-conjugated semiconducting block copolymers is presented and the prototype exhibits nanoscopic phase domain separation and good mobility.
Tuning the properties of α,ω-bis(trialkoxysilyl) telechelic copolyolefins from ruthenium-catalyzed chain-transfer ring-opening metathesis polymerization (ROMP)
Authors: Michel Xiaolu , Fouquay Stéphane , Michaud Guillaume , Simon Frédéric , Brusson Jean-Michel , Roquefort Philippe , Aubry Thierry , Carpentier Jean-François , Guillaume Sophie M.
Published: January 2017

Low viscosity liquid α,ω-bis(trialkoxysilyl) telechelic copolyolefins are reported.
Facile synthesis of Mn3[Co(CN)6]2·nH2O nanocrystals for high-performance electrochemical energy storage devices
Authors: Zhao Qunxing , Zhao Mingming , Qiu Jiaqing , Pang Huan , Lai Wen-Yong , Huang Wei
Published: January 2017

Mn3[Co(CN)6]2·nH2O nanocrystals are firstly applied in flexible solid-state electrochemical energy storage devices.
Electrolytes for electrochemical energy storage
Authors: Xia Lan , Yu Linpo , Hu Di , Chen George Z.
Published: January 2017

Innovative salt solutions and liquid salts can advance batteries, supercapacitors, and supercapatteries for stationary, transport, seasonal and regional energy storage.
Optimization of perovskite by 3D twisted diketopyrrolopyrrole for efficient perovskite solar cells
Authors: Huang Bin , Fu Qingxia , Ai Qingyun , Tan Licheng , Chen Lie , Chen Yiwang
Published: January 2017

The perovskite solar cells obtained with TPE-DPP4 resulted in an enhanced PCE of 14.1% with 40% enhancement to the device compared with pristine perovskite.
Site-selective oxidative C–H sulfonylation of 8-acylaminoquinolines and anilides under metal-free conditions
Authors: Wang Yang , Wang Ying , Zhang Qian , Li Dong
Published: January 2017

A highly site-selective oxidative C–H sulfonylation method for 8-acylaminoquinolines and anilides with sulfonyl chlorides has been developed, which provided C5-sulfonylated quinolines andpara-sulfonylated anilides respectively.
Transition metal- and organophotocatalyst-free perfluoroalkylation reaction of amino(hetero)aromatics initiated by the complex [(TMEDA)I·I3] and visible light
Authors: Yerien Damian E. , Conde Romina , Barata-Vallejo Sebastian , Camps Bruno , Lantaño Beatriz , Postigo Al
Published: January 2017

Radical initiation for the perfluoroalkylation reaction of amino(hetero)aromatics has been accomplished employing the complex [(TMEDA)I·I3] and visible light.
Mn3O4/graphene nanocomposites: outstanding performances as highly efficient photocatalysts and microwave absorbers
Authors: Amer Ahmed A. , Reda S. M. , Mousa M. A. , Mohamed Mohamed Mokhtar
Published: January 2017

Mn3O4 incorporated graphenes synthesized by a deposition-solvothermal process were efficiently used for methylene blue degradation under visible illumination (88 W, λ > 420 nm) and under microwave irradiation (800 W, 2.45 GHz, 373 K).
Reversible gating of ion transport through DNA-functionalized carbon nanotube membranes
Authors: Shadmehr Samaneh , Coleman Michael , Liu Biwu , Liu Juewen , Tang Xiaowu (Shirley)
Published: January 2017

A robust carbon nanotube (CNT) membrane using DNA as the gatekeeper molecule to reversibly open and close CNT inner pores for ion transport.
Ion-specific ice propagation behavior on polyelectrolyte brush surfaces
Authors: Liu Zhenqi , He Zhiyuan , Lv Jianyong , Jin Yuankai , Wu Shuwang , Liu Guangming , Zhou Feng , Wang Jianjun
Published: January 2017

Various hydration states of PB lead to a difference of ice propagation rate up to five orders of magnitude.
Reaction mechanisms in swelling clays under ionizing radiation: influence of the water amount and of the nature of the clay mineral
Authors: Lainé M. , Balan E. , Allard T. , Paineau E. , Jeunesse P. , Mostafavi M. , Robert J.-L. , Le Caër S.
Published: January 2017

Picosecond pulse radiolysis experiments performed on natural swelling clays evidence a fast trapping of electrons in the layers of the material.
High efficiency conjugated polymer/Si hybrid solar cells with tetramethylammonium hydroxide treatment
Authors: Shen Xiaojuan , Ma Baogen , Chen Ling , Zhao Jie
Published: January 2017

Conjugated polymer/Si hybrid solar cells are fabricated based on a Si nanowire array (SiNW) substrate prepared by metal-assisted electroless etching.
Cm-size free-standing self-organized buckypaper of bucky-onions filled with ferromagnetic Fe3C
Authors: Boi Filippo S. , Guo Jian , Xiang Gang , Lan Mu , Wang Shanling , Wen Jiqiu , Zhang Sijie , He Yi
Published: January 2017

Novel cm-size free-standing buckypapers of bucky-onions filled with a single-phase of ferromagnetic Fe3C single crystals were serendipitously discovered.
Enhanced flame-retardant effect of a montmorillonite/phosphaphenanthrene compound in an epoxy thermoset
Authors: Tang Shuo , Wachtendorf Volker , Klack Patrick , Qian Lijun , Dong Yuping , Schartel Bernhard
Published: January 2017

The protective barrier effect of OMMT and the flame-inhibition effect of TAD jointly exerted a superior flame-retardant effect, resulting in sufficient flame-retardant effect on epoxy thermosets.
Generation of 3-dimensional polymer structures in liquid crystalline devices using direct laser writing
Authors: Tartan C. C. , Salter P. S. , Wilkinson T. D. , Booth M. J. , Morris S. M. , Elston S. J.
Published: January 2017

We demonstrate laser writing of birefringent polymer structures with a controllable orientation of the optic axis in liquid crystal devices.
The oxygen reduction reaction mechanism on Sn doped graphene as an electrocatalyst in fuel cells: a DFT study
Authors: Sun Xiaoxu , Li Kai , Yin Cong , Wang Ying , He Feng , Bai Xiaowan , Tang Hao , Wu Zhijian
Published: January 2017

Heteroatom doped graphene has caused particular interest in recent years due to its promising ORR (oxygen reduction reaction) activity in fuel cells.
High-performance all-solid-state flexible carbon/TiO2micro-supercapacitors with photo-rechargeable capability
Authors: Cai Jinguang , Lv Chao , Watanabe Akira
Published: January 2017

A high-performance all-solid-state flexible carbon/TiO2micro-supercapacitor with photo-rechargeable capability was prepared by combining a laser direct writing technique with electrophoretic deposition.
Carbon-dot–hydrogel for enzyme-mediated bacterial detection
Authors: Bhattacharya Sagarika , Nandi Sukhendu , Jelinek Raz
Published: January 2017

A hybrid carbon-dot (C-dot)–hydrogel matrix was constructed and employed for detection of bacteria.
Matrix-isolation and theoretical study of the HXeCCXeH⋯HCCH and HXeCC⋯HCCH complexes
Authors: Duarte Luís , Khriachtchev Leonid
Published: January 2017

HXeCCXeH and HXeCC noble-gas hydrides complexed with acetylene.
Dietary supplementation of Thai black rice bran extract and yeast beta-glucan protects the dextran sodium sulphate mediated colitis induced rat
Authors: Pengkumsri Noppawat , Sivamaruthi Bhagavathi Sundaram , Sirilun Sasithorn , Suwannalert Prasit , Rodboon Teerapat , Prasitpuriprecha Chutinun , Peerajan Sartjin , Butrungrod Widawal , Chaiyasut Chaiyavat
Published: January 2017

The present study was employed to evaluate the impact of black rice bran (RB) extract, and yeast β-glucan (YBG) supplementation on a dextran sodium sulfate (DSS)-induced colitis rat model.
Biocompatible, optically transparent, patterned, and flexible electrodes and radio-frequency antennas prepared from silk protein and silver nanowire networks
Authors: Min Kyungtaek , Umar Muhammad , Seo Haekyo , Yim Jong Hyuk , Kam Dong Gun , Jeon Heonsu , Lee Soonil , Kim Sunghwan
Published: January 2017

We demonstrated biocompatible, optically transparent and flexible electrodes by embedding AgNWs just below the surface of the silk fibroin film.
Ammonium level induces high purity propionate production in mixed culture glucose fermentation
Authors: Chen Yun , Shen Nan , Wang Ting , Zhang Fang , Zeng Raymond J.
Published: January 2017

Propionate is an important chemical widely applied in industry and its productionviafermentation is economic.
Interdigitated crystalline MMT–MCA in polyamide 6
Authors: Zhao Min , Yi Deqi , Camino Giovanni , Frache Alberto , Yang Rongjie
Published: January 2017

A novel interdigitated crystalline MMT–MCA shows outstanding fire retardancy owing to homogeneous dispersion of MMT and MCA in PA6.
Oxidative decarboxylative radical trifluoromethylthiolation of alkyl carboxylic acids with silver(i) trifluoromethanethiolate and selectfluor
Authors: He Bin , Xiao Zhiwei , Wu Hao , Guo Yong , Chen Qing-Yun , Liu Chao
Published: January 2017

Practical, mild, and efficient. Broad scope and good functional group tolerance.
DNA intercalators as amyloid assembly modulators: mechanistic insights
Authors: Singh Jasdeep , Srivastava Ankit , Sharma Pankaj , Pradhan Prashant , Kundu Bishwajit
Published: January 2017

DNA intercalators modulate amyloid assembly of proteins through specific hetero-aromatic interactions diverting them to form amorphous aggregates.
Chelating magnetic nanocomposite for the rapid removal of Pb(ii) ions from aqueous solutions: characterization, kinetic, isotherm and thermodynamic studies
Authors: Moradi Atefeh , Najafi Moghadam Peyman , Hasanzadeh Reza , Sillanpää Mika
Published: January 2017

Fe3O4@GMA–AAm nanocomposite as a novel adsorbent with high adsorption capacity for rapid removal of Pb2+from aqueous media was synthesized.
Simultaneous impedance spectroscopy and fluorescence microscopy for the real-time monitoring of the response of cells to drugs
Authors: Parviz M. , Gaus K. , Gooding J. J.
Published: January 2017

A dual fluorescence microscopy and electrochemical strategy to investigate how cell–surface interactions influence the cellular responses to cues for the cell-based biosensing of drug efficacy is reported herein.
Silica-supported isolated gallium sites as highly active, selective and stable propane dehydrogenation catalysts
Authors: Searles Keith , Siddiqi Georges , Safonova Olga V. , Copéret Christophe
Published: January 2017

Single-site gallium centers, obtained via grafting of a molecular siloxide precursor on the surface of partially dehydroxylated silica followed and a thermal transformation, display high initial activity for propane dehydrogenation, (TOF 20 mol C3H6 per mol Ga per h), and high selectivity for propylene (≥93) over 20 h.
2-Methoxyethanol as a new solvent for processing methylammonium lead halide perovskite solar cells
Authors: Hendriks Koen H. , van Franeker Jacobus J. , Bruijnaers Bardo J. , Anta Juan A. , Wienk Martijn M. , Janssen René A. J.
Published: January 2017

The higher volatility of 2-methoxyethanol compared to that of commonly usedN,N-dimethylformamide results in compact perovskite layers with increased photovoltaic performance.
High performance Al–AlN solar spectrally selective coatings with a self-assembled nanostructure AlN anti-reflective layer
Authors: Wang Chengbing , Cheng Wei , Ma Pengjun , Xia Rongbin , Ling Xiaoming
Published: January 2017

The almost super-hydrophobic nanostructure AlN anti-reflective layer can effectively enhance light absorption and prevent surface contamination of Al–AlN absorber coatings.
Atomic interpretation of high activity on transition metal and nitrogen-doped carbon nanofibers for catalyzing oxygen reduction
Authors: Yan Xingxu , Liu Kexi , Wang Tuo , You Yong , Liu Jianguo , Wang Peng , Pan Xiaoqing , Wang Guofeng , Luo Jun , Zhu Jing
Published: January 2017

We interpreted the effects of transition metals and electrolytes on the ORR activity based on high-resolution STEM-EDX mapping and DFT calculations.
Bottom-up design of de novo thermoelectric hybrid materials using chalcogenide resurfacing
Authors: Sahu Ayaskanta , Russ Boris , Su Norman C. , Forster Jason D. , Zhou Preston , Cho Eun Seon , Ercius Peter , Coates Nelson E. , Segalman Rachel A. , Urban Jeffrey J.
Published: January 2017

Molecular engineering at the organic/inorganic interface enables robust bottom-up design of solution processable p- and n-type hybrid nanostructures for thermoelectrics.
Designing strontium titanate-based thermoelectrics: insight into defect chemistry mechanisms
Authors: Kovalevsky Andrei V. , Aguirre Myriam H. , Populoh Sascha , Patrício Sonia G. , Ferreira Nuno M. , Mikhalev Sergey M. , Fagg Duncan P. , Weidenkaff Anke , Frade Jorge R.
Published: January 2017

The work establishes a closer link between the defect chemistry and thermoelectric properties of strontium titanate-based materials, by uncovering particular roles of various defects in electronic and thermal transport.
Gastrointestinal tract mechanism of nitrite capture modeled on the self assembled monolayer of thioproline for electrochemical nitrite determination
Authors: Singh Nimisha , Patel Khushbu , Sahoo Suban K. , Pati Ranjan K. , Kumar Rajender
Published: January 2017

Gastrointestinal (GI) tract has a unique mechanism for nitric oxide (NO) capture in the form of N-nitrosamines.
Understanding surface chemistry during MAPbI3 spray deposition and its effect on photovoltaic performance
Authors: Rocks Conor , Svrcek Vladimir , Maguire Paul , Mariotti Davide
Published: January 2017

Sprayed MAPbI3 films exhibit changing surface chemistry that affects electronic band alignment and PV performance. Results highlight the potential for a low costing spray deposition technique.
Three-Dimensional Printing: Custom-Made Implants for Craniomaxillofacial Reconstructive Surgery
Authors: Matias Mariana , Zenha Horácio , Costa Horácio
Published: January 2017

Craniomaxillofacial reconstructive surgery is a challenging field. First it aims to restore primary functions and second to preserve craniofacial anatomical features like symmetry and harmony. Three-dimensional (3D) printed biomodels have been widely adopted in medical fields by providing tactile feedback and a superior appreciation of visuospatial relationship between anatomical structures. Craniomaxillofacial reconstructive surgery was one of the first areas to implement 3D printing technology in their practice. Biomodeling has been used in craniofacial reconstruction of traumatic injuries, congenital disorders, tumor removal, iatrogenic injuries (e.g., decompressive craniectomies), orthognathic surgery, and implantology. 3D printing has proven to improve and enable an optimization of preoperative planning, develop intraoperative guidance tools, reduce operative time, and significantly improve the biofunctional and the aesthetic outcome. This technology has also shown great potential in enriching the teaching of medical students and surgical residents. The aim of this review is to present the current status of 3D printing technology and its practical and innovative applications, specifically in craniomaxillofacial reconstructive surgery, illustrated with two clinical cases where the 3D printing technology was successfully used.
Magnetic symmetry dependent wall domain motion mechanisms in two-dimensional ferromagnetic systems
Authors: Ryu Kwang-Su , Shin Sung-Chul
Published: January 2017

We report the systematic change of the domain wall (DW) motion mechanism depending on the ratio of composition x in two-dimensional Co1−xFex ferromagnetic systems (0.0 ≤ x ≤ 1.0) by means of the direct domain observation. Interestingly, as the Fe composition x increases, the DW motion mechanism becomes changed from the stochastic behavior with random DW sizes to the thermally activated behavior with specific DW sizes. This result could be understood by the change of the magnetic angular symmetry from a 2-fold one to a 4-fold one with increasing the Fe composition, responsible for the change of the DW type.
Vacuum-ultraviolet frequency-modulation spectroscopy
Authors: Hollenstein U. , Schmutz H. , Agner J. A. , Sommavilla M. , Merkt F.
Published: January 2017

Frequency-modulation (FM) spectroscopy has been extended to the vacuum-ultraviolet (VUV) range of the electromagnetic spectrum. Coherent VUV laser radiation is produced by resonance-enhanced sum-frequency mixing (νVUV=2νUV+ν2) in Kr and Xe using two near-Fourier-transform-limited laser pulses of frequencies νUV and ν2. Sidebands generated in the output of the second laser (ν2) using an electro-optical modulator operating at the frequency νmod are directly transferred to the VUV and used to record FM spectra. Demodulation is demonstrated both at νmod and 2νmod. The main advantages of the method compared to VUV absorption spectroscopy are its background-free nature, the fact is that its implementation using table-top laser equipment is straightforward and that it can be used to record VUV absorption spectra of cold samples in skimmed supersonic beams simultaneously with laser-induced-fluorescence and photoionization spectra. To illustrate these advantages, we present VUV FM spectra of Ar, Kr, and N2 in selected regions between 105000 cm−1 and 122000 cm−1.
Predicting efficiency of solar cells based on transparent conducting electrodes
Authors: Kumar Ankush
Published: January 2017

Efficiency of a solar cell is directly correlated with the performance of its transparent conducting electrodes (TCEs) which dictates its two core processes, viz., absorption and collection efficiencies. Emerging designs of a TCE involve active networks of carbon nanotubes, silver nanowires and various template-based techniques providing diverse structures; here, voids are transparent for optical transmittance while the conducting network acts as a charge collector. However, it is still not well understood as to which kind of network structure leads to an optimum solar cell performance; therefore, mostly an arbitrary network is chosen as a solar cell electrode. Herein, we propose a new generic approach for understanding the role of TCEs in determining the solar cell efficiency based on analysis of shadowing and recombination losses. A random network of wires encloses void regions of different sizes and shapes which permit light transmission; two terms, void fraction and equivalent radius, are defined to represent the TCE transmittance and wire spacings, respectively. The approach has been applied to various literature examples and their solar cell performance has been compared. To obtain high-efficiency solar cells, optimum density of the wires and their aspect ratio as well as active layer thickness are calculated. Our findings show that a TCE well suitable for one solar cell may not be suitable for another. For high diffusion length based solar cells, the void fraction of the network should be low while for low diffusion length based solar cells, the equivalent radius should be lower. The network with less wire spacing compared to the diffusion length behaves similar to continuous film based TCEs (such as indium tin oxide). The present work will be useful for architectural as well as material engineering of transparent electrodes for improvisation of solar cell performance.
Chirp Z transform based enhanced frequency resolution for depth resolvable non stationary thermal wave imaging
Authors: Suresh B. , Subhani Sk. , Vijayalakshmi A. , Vardhan V. H. , Ghali V. S.
Published: January 2017

This paper proposes a novel post processing modality to enhance depth resolution in frequency modulated thermal wave imaging using chirp Z transform. It explores the spectral zooming feature of the proposed modality to enhance depth resolution and validates it through the experimentation carried over a carbon fiber reinforced plastic and mild steel specimens. Further, defect detection capability of the proposed modality has been compared with that of the other contemporary modalities by taking the defect signal to noise ratio into consideration.
Control of bifurcation-delay of slow passage effect by delayed self-feedback
Authors: Premraj D. , Suresh K. , Banerjee Tanmoy , Thamilmaran K.
Published: January 2017

The slow passage effect in a dynamical system generally induces a delay in bifurcation that imposes an uncertainty in the prediction of the dynamical behaviors around the bifurcation point. In this paper, we investigate the influence of linear time-delayed self-feedback on the slow passage through the delayed Hopf and pitchfork bifurcations in a parametrically driven nonlinear oscillator. We perform linear stability analysis to derive the Hopf bifurcation point and its stability as a function of self-feedback time delay. Interestingly, the bifurcation-delay associated with Hopf bifurcation behaves differently in two different edges. In the leading edge of the modulating signal, it decreases with increasing self-feedback delay, whereas in the trailing edge, it behaves in an opposite manner. We also show that the linear time-delayed self-feedback can reduce bifurcation-delay in pitchfork bifurcation. These results are illustrated numerically and corroborated experimentally. We also propose a mechanistic explanation of the observed behaviors. In addition, we show that our observations are robust in the presence of noise. We believe that this study of interplay of two time delays of different origins will shed light on the control of bifurcation-delay and improve our knowledge of time-delayed systems.
Vortex identification from local properties of the vorticity field
Authors: Elsas J. H. , Moriconi L.
Published: January 2017

A number of systematic procedures for the identification of vortices/coherent structures have been developed as a way to address their possible kinematical and dynamical roles in structural formulations of turbulence. It has been broadly acknowledged, however, that vortex detection algorithms, usually based on linear-algebraic properties of the velocity gradient tensor, can be plagued with severe shortcomings and may become, in practical terms, dependent on the choice of subjective threshold parameters in their implementations. In two-dimensions, a large class of standard vortex identification prescriptions turn out to be equivalent to the “swirling strength criterion” (λci-criterion), which is critically revisited in this work. We classify the instances where the accuracy of the λci-criterion is affected by nonlinear superposition effects and propose an alternative vortex detection scheme based on the local curvature properties of the vorticity graph (x,y,ω)—the “vorticity curvature criterion” (λω-criterion)—which improves over the results obtained with the λci-criterion in controlled Monte Carlo tests. A particularly problematic issue, given its importance in wall-bounded flows, is the eventual inadequacy of the λci-criterion for many-vortex configurations in the presence of strong background shear. We show that the λω-criterion is able to cope with these cases as well, if a subtraction of the mean velocity field background is performed, in the spirit of the Reynolds decomposition procedure. A realistic comparative study for vortex identification is then carried out for a direct numerical simulation of a turbulent channel flow, including a three-dimensional extension of the λω-criterion. In contrast to the λci-criterion, the λω-criterion indicates in a consistent way the existence of small scale isotropic turbulent fluctuations in the logarithmic layer, in consonance with long-standing assumptions commonly taken in turbulent boundary layer phenomenology.
Analytic gradients for natural orbital functional theory
Authors: Mitxelena Ion , Piris Mario
Published: January 2017

The analytic energy gradients with respect to nuclear motion are derived for the natural orbital functional (NOF) theory. The resulting equations do not require resorting to linear-response theory, so the computation of NOF energy gradients is analogous to gradient calculations at the Hartree-Fock level of theory. The structures of 15 spin-compensated systems, composed of first- and second-row atoms, are optimized employing the conjugate gradient algorithm. As functionals, two orbital-pairing approaches were used, namely, the fifth and sixth Piris NOFs (PNOF5 and PNOF6). For the latter, the obtained equilibrium geometries are compared with coupled cluster singles and doubles calculations and accurate empirical data.
Carrier localization in the vicinity of dislocations in InGaN
Authors: Massabuau F. C-P. , Chen P. , Horton M. K. , Rhode S. L. , Ren C. X. , O'Hanlon T. J. , Kovács A. , Kappers M. J. , Humphreys C. J. , Dunin-Borkowski R. E. , Oliver R. A.
Published: January 2017

We present a multi-microscopy study of dislocations in InGaN, whereby the same threading dislocation was observed under several microscopes (atomic force microscopy, scanning electron microscopy, cathodoluminescence imaging and spectroscopy, transmission electron microscopy), and its morphological optical and structural properties directly correlated. We achieved this across an ensemble of defects large enough to be statistically significant. Our results provide evidence that carrier localization occurs in the direct vicinity of the dislocation through the enhanced formation of In-N chains and atomic condensates, thus limiting non-radiative recombination of carriers at the dislocation core. We highlight that the localization properties in the vicinity of threading dislocations arise as a consequence of the strain field of the individual dislocation and the additional strain field building between interacting neighboring dislocations. Our study therefore suggests that careful strain and dislocation distribution engineering may further improve the resilience of InGaN-based devices to threading dislocations. Besides providing a new understanding of dislocations in InGaN, this paper presents a proof-of-concept for a methodology which is relevant to many problems in materials science.
Identification and separation of rectifier mechanisms in Si/SiGe ballistic cross junctions
Authors: von Pock J. F. , Salloch D. , Wieser U. , Hackbarth T. , Kunze U.
Published: January 2017

Depending on the detailed geometry, gate voltage, and circuitry, nanoscale Si/SiGe cross junctions at low temperatures exhibit full-wave rectification arising from different mechanisms like change in the number of current-carrying modes, stationary ballistic charging of a current-free voltage lead, and hot-electron thermopower. We study the rectifier structures on high-mobility Si/SiGe heterostructures consisting of a straight voltage stem and oblique current-injecting leads. Local gate electrodes are used to control the electron density in the voltage or current channel. Compared to three-terminal Y-branch junctions, the four-terminal cross junction eliminates the mode effect. A gradual increase of output voltage as gate-voltage is reduced until threshold voltage is identified as contribution of hot-electron thermopower. Heating the initially cold reservoir from a second orthogonal cross junction eliminates the electron temperature gradient and suppresses the thermopower. Even if the operation as six-terminal device re-induces a mode-controlled contribution, we demonstrate that it is negligible. As expected, the ballistic signal can be reliably separated from other mechanisms by measurements under positive gate voltage. The ballistic voltage can be described by a parabolic function of the injected current and is proportional to the cosine of the injection angle.
Simultaneous measurement of in-plane and through-plane thermal conductivity using beam-offset frequency domain thermoreflectance
Authors: Rodin David , Yee Shannon K.
Published: January 2017

Transient thermoreflectance (TTR) techniques are ubiquitous methods for measuring thermal conductivity of bulk materials and thin-films. Both through-plane thermal conductivity k⊥ and in-plane thermal conductivity k∥ should be independently measured in transversely anisotropic materials. When these properties are measured using conventional TTR techniques, the accuracy of the k∥ measurement is dependent on the accuracy of measuring k⊥ and vice versa. This is especially problematic for thin-films measurements as uncertainty in k⊥ (∼5%) can propagate and grow for uncertainty in k∥. In this paper, we present a method for the simultaneous measurement of k⊥ and k∥ using beam-offset frequency domain thermoreflectance (FDTR) with robust uncertainty estimation. The conventional diffusive heat transfer solution is analyzed to show that offset and heating frequency can independently control the sensitivity to directional thermal conductivity and extract values for k∥ and k⊥. Numerical uncertainty analyses demonstrate that sweeping both heating frequency and beam offset results in a reduction of measurement uncertainty. This modified measurement technique is demonstrated on crystalline alumina (c-Al2O3), amorphous alumina (a-Al2O3), quartz, fused silica, and highly oriented pyrolytic graphite.
Nanoscale visualization of electronic properties of AlxGa1-xN/AlyGa1-yN multiple quantum-well heterostructure by spreading resistance microscopy
Authors: Sviridov D. E. , Kozlovsky V. I. , Rong X. , Chen G. , Wang X. , Jmerik V. N. , Kirilenko D. A. , Ivanov S. V.
Published: January 2017

Cross-sectional spreading resistance microscopy has been used to investigate nanoscale variations in electronic properties of an undoped Al0.75Ga0.25N/Al0.95Ga0.05N multiple quantum well (MQW) heterostructure grown by plasma-assisted molecular beam epitaxy on an AlN/c-sapphire template, prepared by metalorganic vapor phase epitaxy. It is found that a current signal from the MQWs can be detected only at a negative sample bias. Moreover, its value changes periodically from one quantum well (QW) to another. Analysis of the current-voltage characteristics of the contacts of a tip with the structure layers showed that periodic contrast of MQWs is the result of fluctuations of the chemical composition of the QWs and the concentration of electrons accumulated in them. Mathematical simulations indicate that this modulation is associated with the periodic fluctuations of an Al-mole fraction in the barrier layers of the structure due to counter gradients of the intensity of Al and Ga molecular fluxes across the surface of a substrate rotating slowly during growth. The nanoscale fluctuations of the current contrast observed along the QW layers are caused, most likely, by the presence of the areas of lateral carrier localization, which originate during the formation of QWs by sub-monolayer digital alloying technique.
A novel Ku-band relativistic transit-time oscillator with three-cavity extractor and distance-tunable reflector
Authors: Ling Junpu , He Juntao , Zhang Jiande , Song Lili , Gao Minghao
Published: January 2017

A novel Ku-band relativistic transit-time oscillator with a three-cavity extractor and a distance-tunable reflector is proposed. The physical mechanism of the three-cavity extractor and distance-tunable reflector is investigated by theory and simulation. It is shown that by introducing a three-cavity extractor instead of the dual-cavity one, the novel device has higher power capacity. Meanwhile, the three-cavity extractor is more favorable for increasing the beam-wave conversion efficiency of the device. In addition, analysis indicates that the distance-tunable reflector employed in the device plays important roles in the enhancement of conversion efficiency. Particle-in-cell simulations show that with the three-cavity extractor and distance-tunable reflector, this proposed device generates a 12.4 GHz, 2.2 GW microwave, while the diode voltage is 570 kV, the beam current is 10.5 kA, and the guiding magnetic field is 0.7 T. The corresponding power efficiency reaches 37%.
Understanding of one dimensional ordering mechanisms at the (001) sapphire vicinal surface
Authors: Thune E. , Fakih A. , Matringe C. , Babonneau D. , Guinebretière R.
Published: January 2017

Vicinal sapphire surfaces with 1°, 5°, or 10° miscut angle from the (00l) planes have been annealed under different atmospheres in the temperature range from 1000 to 1500 °C for a long time (from 30 min to 64 h). A systematic study by atomic force microscopy observations and grazing incidence small angle x-ray scattering measurements is undertaken in order to establish the influence of the miscut angle and the thermal conditions on the one dimensional (1D) ordering of the surface and on the resulting surface morphology. Several stages are identified in the evolution of the step period. First, after a very short time τ of thermal treatment, the surface reaches a periodic structure which corresponds to the self-ordering of single steps. Then, the step-bunching occurs, and the step period Λ increases following a power-law Λ=Λ0(t−ττ)n. Respect to the miscut angle, we identified several mechanisms of mass transport. Indeed, for surfaces with a miscut angle of 1°, the kinetics of step-bunching is controlled by diffusion of aluminum atoms, while, for miscut angles equal to 5° and 10°, the kinetics of step diffusion mechanism is governed by diffusion of oxygen atoms at the surface.
An in situ synchrotron XAS methodology for surface analysis under high temperature, pressure, and shear
Authors: Dorgham A. , Neville A. , Ignatyev K. , Mosselmans F. , Morina A.
Published: January 2017

The complex tribochemical nature of lubricated tribological contacts is inaccessible in real time without altering their initial state. To overcome this issue, a new design of a pin-on-disc tribological apparatus was developed and combined with synchrotron X-ray absorption spectroscopy (XAS). Using the designed apparatus, it is possible to study in situ the transient decomposition reactions of various oil additives on different surfaces under a wide range of realistic operating conditions of contact pressure (1.0–3.0 GPa), temperature (25–120 °C), and sliding speed (30–3000 rpm or 0.15–15 m/s). To test the apparatus, several tribological tests were performed at different shearing times ranging from 2.5 to 60 min. These tests were carried out under helium atmosphere at a temperature of 80  °C, contact pressure of 2.2 GPa, and sliding speed of 50 rpm. The XAS experiments indicate that the zinc dialkyldithiophosphate antiwear additive decomposes in the oil to form a tribofilm on the iron surface at different reaction kinetics from the ones of the thermal film. The tribofilm composition evolves much faster than the one of the thermal film, which confirms that the formation of the tribofilm is a thermally activated process similar to the one of the thermal film but accelerated by shear. Furthermore, the results indicate that the sulfur of the formed film, whether a tribofilm or a thermal film, appears initially in the form of sulfate, with some sulfide, which under heat or shear is reduced into mainly sulfide.
Fermi-level pinning of bilayer graphene with defects under an external electric field
Authors: Kishimoto Ken , Okada Susumu
Published: January 2017

The electronic structure of bilayer graphene, where one of the layers possesses monovacancies, is studied under an external electric field using density functional theory. Our calculations show that Fermi-level pinning occurs in the bilayer graphene with defects under hole doping. However, under electron doping, the Fermi level rapidly increases at the critical gate voltage with an increasing electron concentration. In addition to the carrier species, the relative arrangement of the gate electrode to the defective graphene layer affects the Fermi energy position with respect to the carrier concentration. Because the distribution of the accumulated carrier depends on the electrode position, the quantum capacitance of bilayer graphene with defects depends on the electrode position.
Non-radiative energy transfer in quantum dot ensemble mediated by localized surface plasmon
Authors: Lyamkina A. A. , Dmitriev D. V. , Toropov A. I. , Moshchenko S. P.
Published: January 2017

Exciton-plasmon interaction was studied experimentally in structures with InAs/AlGaAs quantum dots (QDs) and indium nanoclusters grown by molecular beam epitaxy. In photoluminescence (PL) spectra, a strong enhancement of low energy QDs was observed that resulted in a new peak. This effect is explained with the plasmon-assisted energy transfer from an ensemble of donor QDs located under a metal cluster to a low energy acceptor QD. The dependence of the integrated PL signal of the low new peak on the QD number under an individual metal cluster changed from linear to quadratic and revealed the transition from a single to many interacting QDs.