bluuebunny/crossref_metadata_2025 huggingface dataset:
Conformational features of 4-(N)-squalenoyl-gemcitabine in solution: a combined NMR and molecular dynamics investigation
Authors: Maurizio Ceruti , Flavio Rocco , Maria Enrica Di Pietro , Elena Tocci , Giuseppina De Luca
Published: February 2015

Folded conformations of 4-(N)-squalenoyl-gemcitabine in solution are obtained from a comparison of experimental and theoretical J-couplings.
An electrochemical immunoassay based on trepang-like gold electrodes and nanogold functionalized flower-like hierarchical carbon materials with improved sensitivity
Authors: Wu Kaiqing , Zhang Yan , Yan Mei , Ge Shenguang , Yu Jinghua , Song Xianrang
Published: February 2015

A novel electrochemical immunosensor based on a 3D-TG/G-PDDA modified electrode was designed for sensitive detection of CEA using AuNP functionalized FCM as a nanocarrier.
Chemistry and biology of tubulysins: antimitotic tetrapeptides with activity against drug resistant cancers
Authors: Murray Bryan C. , Peterson Michael T. , Fecik Robert A.
Published: February 2015

Since their first report in 2000, tubulysins have sparked great interest for development as anti-cancer agents due to their exceptionally potent anticancer activity.
Bichromophoric dyes for wavelength shifting of dye-protein fluoromodules
Authors: Pham Ha H. , Szent-Gyorgyi Christopher , Brotherton Wendy L. , Schmidt Brigitte F. , Zanotti Kimberly J. , Waggoner Alan S. , Armitage Bruce A.
Published: February 2015

Dye-protein fluoromodules consist of fluorogenic dyes and single chain antibody fragments that form brightly fluorescent noncovalent complexes.
Effect of different coating materials on the biological characteristics and stability of microencapsulated Lactobacillus acidophilus
Authors: Xing Yage , Xu Qinglian , Jiang Li , Cao Dong , Lin Hongbin , Che Zhenming , Ma Yuan , Li Xingchen , Cai Yimin
Published: February 2015

MicroencapsulatedL. acidophilusembedded with different wall materials exhibited different biological characteristics and stability. Complex materials as coatings could provide protection and better release characteristics forL. acidophiluscell.
Chemical bath deposition of Cu2O quantum dots onto ZnO nanorod arrays for application in photovoltaic devices
Authors: Zou Xinwei , Fan Huiqing , Tian Yuming , Zhang Mingang , Yan Xiaoyan
Published: February 2015

A protective CuO layer on the Cu2O quantum dots was prepared by simply heat-treating the Cu2O/ZnO hetero-nanorod arrays in ambient air, which enhances the photovoltaic stability.
Nano CuFe2O4: an efficient, magnetically separable catalyst for transesterification of β-ketoesters
Authors: Gohain Mukut , Kumar Vinod , van Tonder Johannes H. , Swart Hendrik C. , Ntwaeaborwa Odireleng M. , Bezuidenhoudt Barend C. B.
Published: February 2015

The preparation of a variety of β-ketoesters was achieved in high yields from methyl acetoacetate under neutral conditions through the utilization of magnetic CuFe2O4nanoparticles as catalyst.
Green synthesis of monodispersed LaCO3OH microgears with novel plum blossom-like structure via a glycerol-mediated solvothermal method
Authors: Zhang Yong-Xing , Zhou Xiang-Bo , Liu Zhong-Liang , Liu Qin-Zhuang , Zhu Guang-Ping , Dai Kai , Li Bing , Sun Bai , Jin Zhen , Li Xuan-Hua
Published: February 2015

A novel LaCO3OH microgear has been synthesized by a green method, which shows strong PL properties.
Enhanced adsorption of inorganic and organic pollutants by amine modified sodium montmorillonite nanosheets
Authors: Munusamy Thirumavalavan , Ya-Ting Jhuang , Jiunn-Fwu Lee
Published: February 2015

Amine modified sodium montmorillonite nanosheets with increased basal space as versatile adsorbents for both organic and inorganic pollutants.
One-step synthesis of a copper-based metal–organic framework–graphene nanocomposite with enhanced electrocatalytic activity
Authors: Yang Juan , Zhao Faqiong , Zeng Baizhao
Published: February 2015

A facile one-step method to prepare a Cu-MOF–graphene composite and its electrochemical application.
Controllable and mass fabrication of highly luminescent N-doped carbon dots for bioimaging applications
Authors: Chen Zhao , Wang Xiaochi , Li Hua , Li Chao , Lu Qinghua , Yang Guang , Long Jiangang , Meng Lingjie
Published: February 2015

A facile but effective bottom-up method was developed for the mass preparation of N-doped carbon dots (N–C-dots) for cell imaging.
Aggregation and thermal gelation of N-isopropylacrylamide based cucurbit[7]uril side-chain polypseudorotaxanes with low pseudorotaxane content
Authors: Chen Hao , Ma Haili , Chieng Yu Yuan , Hou Shengzhen , Li Xu , Tan Yebang
Published: February 2015

Low pseudorotaxane content (≤3 mol%) endows N-isopropylacrylamide based cucurbit[7]uril polypseudorotaxanes unique aggregation and thermal gelation properties.
Low electric field strength self-organization of anodic TiO2nanotubes in diethylene glycol electrolyte
Authors: Kowalski Damian , Mallet Jeremy , Michel Jean , Molinari Michael
Published: February 2015

Synthesis of anodic TiO2nanotubes in diethylene glycol electrolytes allows the precise control of their growth. We shed light on how the TiO2nanotubes are self-organized under low electric field strength conditions.
Effective adsorption of chromium(vi)/Cr(iii) from aqueous solution using ionic liquid functionalized multiwalled carbon nanotubes as a super sorbent
Authors: Krishna Kumar A. Santhana , Jiang Shiuh-Jen , Tseng Wei-Lung
Published: February 2015

We report an interesting interaction between oxidized multiwalled carbon nanotubes (oxi-MWCNTs), tetra n-heptylammonium bromide (ionic liquid) and Cr(vi)/Cr(iii).
Activated interiors of clay nanotubes for agglomeration-tolerant automotive exhaust remediation
Authors: Sanchez-Ballester Noelia M. , Ramesh Gubbala V. , Tanabe Toyokazu , Koudelkova Eva , Liu Jia , Shrestha Lok Kumar , Lvov Yuri , Hill Jonathan P. , Ariga Katsuhiko , Abe Hideki
Published: February 2015

Naturally occurring clay nanotubes, halloysite, act as a high-performance exhaust catalyst when copper–nickel alloy nanoparticles are dispersed onto the interior surface.
Biomimetic self-assembly of recombinant marine snail egg capsule proteins into structural coiled-coil units
Authors: Fu Tianpei , Guerette Paul A. , Tan Raymond Y. T. , Zhao Hua , Schefer Larissa , Mezzenga Raffaele , Miserez Ali
Published: February 2015

We report on the biomimetic production of shock-absorbing proteins from marine snail egg capsules and their self-assembly into coiled-coil filaments.
Development of bioconjugated dye-doped poly(styrene-co-maleimide) nanoparticles as a new bioprobe
Authors: Swanepoel A. , du Preez I. , Mahlangu T. , Chetty A. , Klumperman B.
Published: February 2015

Fluorescent dye-doped poly(styrene-co-maleimide) nanoparticles were synthesised and functionalized with amine groups and avidin and the dye-loading was varied.
Tri-wavelength broadband antireflective coating built from refractive index controlled MgF2 films
Authors: Ding Ruimin , Cui Xinmin , Zhang Cong , Zhang Ce , Xu Yao
Published: February 2015

Tri-wavelength broadband AR coating derived from refractive index controlled MgF2 films was realized through controlling the self-assembly process of MgF2 nanocrystals.
Pro-fragrant ionic liquids with stable hemiacetal motifs: water-triggered release of fragrances
Authors: Gunaratne H. Q. Nimal , Nockemann Peter , Seddon Kenneth R.
Published: February 2015

Stable hemiacetal pro-fragrances are isolated and the release of the fragrances can be triggered by water.
Coordinated assembly of a new 3D mesoporous Fe3O4@Cu2O–graphene oxide framework as a highly efficient and reusable catalyst for the synthesis of quinoxalines
Authors: Wang Zhiyi , Hu Guowen , Liu Jian , Liu Weisheng , Zhang Haoli , Wang Baodui
Published: February 2015

A novel 3D mesoporous Fe3O4@Cu2O–graphene oxide framework as a highly efficient and reusable catalyst was synthesized.
DNAzyme tunable lead(ii) gating based on ion-track etched conical nanochannels
Authors: Shang YanLi , Zhang Yuqi , Li Pei , Lai Jing , Kong Xiang-Yu , Liu Weida , Xiao Kai , Xie Ganhua , Tian Ye , Wen Liping , Jiang Lei
Published: February 2015

A simple biomimetic ionic gate has been developed by modifying lead(ii) ion responsive DNAzymes onto the inner surface of ion-etched polymer nanochannels.
A novel strategy to synthesize well-defined PS brushes on silica particles by combination of lithium–iodine exchange (LIE) and surface-initiated living anionic polymerization (SI-LAP)
Authors: Min Jiakang , Lin Yichao , Zheng Jun , Tang Tao
Published: February 2015

SiO2 particles coated by well-defined brushlike polystyrene are successfully prepared by the combination of lithium–iodine exchange and surface-initiated living anionic polymerization.
A new fluorogenic probe for the selective detection of carbon monoxide in aqueous medium based on Pd(0) mediated reaction
Authors: Pal Siddhartha , Mukherjee Manjira , Sen Buddhadeb , Mandal Sushil Kumar , Lohar Somenath , Chattopadhyay Pabitra , Dhara Koushik
Published: February 2015

A coumarin-based fluorogenic probe, PCO-1, detects carbon monoxide selectively in buffer at pH 8.0 through the intramolecular cyclization–elimination pathway based on Pd(0) mediated reaction.
Thermoelastic and structural properties of ionically conducting cerate perovskites: (II) SrCeO3 between 1273 K and 1723 K
Authors: Knight Kevin S. , Haynes Richard , Bonanos Nikolaos , Azough Feridoon
Published: February 2015

Thermodynamic grüneisen parameter and bond valence parameters for strontium cerate perovskite.
Effect of the V4+(3+)/V5+ ratio on the denitration activity for V2O5–WO3/TiO2 catalysts
Authors: Dong Guo-jun , Bai Yang , Zhang Yu-feng , Zhao Yuan
Published: February 2015

Variation of monolayer dispersed and polymerized VOx species (a) and apparent activation energy (Ea) of V3W8Ti catalysts.
Modification of chitosan with polystyrene and poly(n-butyl acrylate) via nitroxide-mediated polymerization and grafting from approach in homogeneous media
Authors: García-Valdez O. , Champagne-Hartley R. , Saldívar-Guerra E. , Champagne P. , Cunningham M. F.
Published: February 2015

Nitroxide-mediated polymerization was used to graft modify solubilized chitosan, allowing the reaction to be performed homogeneously.
Thermophilic films and fibers from photo cross-linkable UCST-type polymers
Authors: Liu Fangyao , Jiang Shaohua , Ionov Leonid , Agarwal Seema
Published: February 2015

Photo cross-linkable thermoresponsive polymers of UCST-type and the corresponding thermophilic films and fibers are presented for use in biofabrication and microactuators.
One-step electrochemical synthesis of Bi3.84W0.16O6.24 with superior photocatalytic activities
Authors: Song Zuwei , Dai Hui , Tong Jiantao
Published: February 2015

Bi3.84W0.16O6.24 nanoparticles were successfully prepared by a facile electrochemical route at room temperature in just 10 minutes.
Stimuli-responsive terpolymer mPEG-b-PDMAPMA-b-PAH mediated co-delivery of adriamycin and siRNA to enhance anticancer efficacy
Authors: Xu Minghui , Qian Junmin , Suo Aili , Xu Weijun , Liu Rongrong , Wang Hongjie
Published: February 2015

The adriamycin/P-gp siRNA co-loaded mPEG-b-PDMAPMA-b-PAH terpolymer exhibited pH/reduction dual-responsive payload release behavior and showed a synergistic cytotoxicity against MCF-7/ADR cells.
Redox-economical radical generation from organoborates and carboxylic acids by organic photoredox catalysis
Authors: Chinzei Tatsuya , Miyazawa Kazuki , Yasu Yusuke , Koike Takashi , Akita Munetaka
Published: February 2015

Redox-economical radical reactions by organic photoredox catalysis.
In situ synthesis of mesoporous single-grain layer anatase TiO2 nanosheets without additives via a mild and simple process for a long-term Li-ion battery
Authors: Zhu Kunlei , Liu Xiaoyan , Du Jiangyong , Tian Jianhua , Wang Yun , Liu Shengzhong , Shan Zhongqiang
Published: February 2015

Mesoporous single-grain layer anatase TiO2 nanosheets were first in situ synthesized without additives in a new methanol–tetrabutyl titanate system on a large scale via a simple and easily reproducible method and were applied successfully as anode materials for a long-term Li-ion battery.
Benzodifuran and benzodithiophene donor–acceptor polymers for bulk heterojunction solar cells
Authors: Huang Peishen , Du Jia , Gunathilake Samodha S. , Rainbolt Elizabeth A. , Murphy John W. , Black Kevin T. , Barrera Diego , Hsu Julia W. P. , Gnade Bruce E. , Stefan Mihaela C. , Biewer Michael C.
Published: February 2015

Four new donor–acceptor copolymers were synthesized by using benzo[1,2-b:4,5-b′]dithiophene and benzo[1,2-b:4,5-b′]difuran as donors and thieno[3,4-b]thiophene was used as the acceptor building block.
Min–max mean squared error‐based linear transceiver design for multiple‐input–multiple‐output interference relay channel
Authors: Singh Vindheshwari P. , Chaturvedi Ajit Kumar
Published: February 2015

In this study, the authors consider the min–max mean squared error (MSE)‐based linear transceiver–relay design for multiple‐input–multiple‐output (MIMO) interference relay channel, where a finite number of half‐duplex MIMO amplify and forward relays assist the communication between multiple source–destination pairs. The problem is formulated as minimising the maximum MSE among all data streams of all users subject to individual transmit power constraints at each source and relay node. Since the optimisation problem is non‐convex, globally optimal solution cannot be guaranteed. They propose a suboptimal solution based on alternating minimisation, where the beamforming matrices at all the source, relay and destination nodes are jointly computed in an iterative manner. Numerical simulations show that the proposed algorithm not only ensures fairness among all users’ data streams, but also achieves good sum‐rate and bit error rate performance.
Effect of mechanical milling on the structural and dielectric properties of BaTiO3 powders
Authors: Neogi Samya , Chowdhury Ujjal , Chakraborty Ashim Kumar , Ghosh Jiten
Published: February 2015

Barium titanate (BaTiO3) is a well‐known ferroelectric material and widely used in electronic industries for the multi‐layer ceramic capacitor. In this reported work, commercially available tetragonal BaTiO3 (BT) powders were taken to study the size effect on the structural and dielectric properties of the BT ceramics during high‐energy ball milling (0–110 h). The same perovskite when kept under a normal atmospheric condition after milling shows gradual increase of additional crystalline phase that occurred because of the absorption of atmospheric CO2 gas, which is characterised as orthorhombic BaCO3. The milled BT samples were characterised by X‐ray diffraction and small‐angle X‐ray scattering and a dielectric analyser. The purpose of this work was to study how the dielectric property of nanoBT ceramics varies with reduction of particle size, structural changes and the absorption of carbon by these nanopowders. It was observed that the dielectric constant of the BT powders increases with particle size reduction during milling. The dielectric behaviour of the BT ceramics significantly changes with polymorphic phase transformation in nanocrystalline BT at different stages of milling. The capacitance of nanoBT powders is significantly changed with the absorption of carbon by the nanoBT powders in a humid atmosphere.
Development of liposome‐encapsulated ketoconazole: formulation, characterisation and evaluation of pharmacological therapeutic efficacy
Authors: Ashe Sarbani , Nayak Debasis , Tiwari Gunjan , Rauta Pradipta Ranjan , Nayak Bismita
Published: February 2015

Liposomal formulations containing ketoconazole were prepared with the ultimate goal of increasing their efficacy for topical drug delivery. Various concentrations of drugs were encapsulated within liposomes and characterised by scanning electron microscopy, Fourier transformation infrared spectroscopy, dynamic light scattering studies for size distribution, zeta potential and stability. LIP200 emerged as the best formulation with a size of 178.9 nm, polydispersity index of 0.299 and overall zeta potential of −5.38 mV. The encapsulation efficiency monitored over a period of 28 days varied between 79.6 and 75.4%. The formulation was found to be stable in serum solution with slight changes in size, polydispersity index and charge. The formulation also showed a better anti‐fungal activity against Candida sp. in comparison to other preparations, as well as the control, indicating its potential as a promising topical drug delivery system.
Numerical simulation of droplet‐based microfluidic chip interfacing with laser desorption/ionisation mass spectrometry target substrate
Authors: Tsao Chia‐Wen , Chen Ke‐Siang , Hwang Feng‐Nan
Published: February 2015

Droplet‐based microfluidic devices have shown great potential in biomedical applications. When proteomics bioanalysis or biomarker identification is required, off‐line microfluidic chip interfacing with mass spectrometry (MS) is necessary. This reported work has focused on the use of numerical simulation of microdroplet formation and dripping for a droplet‐based microfluidic‐chip interfacing with off‐line laser desorption/ionisation MS target substrate. Unlike most studies on the microdroplet formation at the liquid–liquid phase, this work has investigated the microdroplet formation at the liquid–gas phase at various injection flow rates and inner microchannel surface wettability to meet microfluidic‐chip–MS interfacing requirements. After the microdroplet formation, subsequent microdroplet dripping analysis was performed. The effects of inner microchannel and outer orifice surface wettability are discussed.
Hydrothermal synthesis of magnetite: investigation of influence of aging time and mechanism
Authors: Sun Xiaoning , Sun Kangning , Liang Yanjie
Published: February 2015

Magnetite (Fe3O4) particles are prepared by a hydrothermal method using ethylene glycol as the solvent. Aging time is a very important factor in the reaction process. The properties and morphology of the products with different aging times are investigated. In the initial stage of the reaction (1 and 2 h), the main powders were iron hydroxides. Fe3O4 particles generated (3 h) and grew into spherical shapes (4–10 h) with the extended aging time. The particle size and the specific saturation magnetisation also varied with aging time. By analysing the powders and the liquids during the reaction, a probable mechanism is studied.
The magnetic phase transition in Mn1.1Fe0.9P1−xGex magnetocaloric alloys
Authors: Chen X. , Ramanujan R. V.
Published: February 2015

Mn-Fe-P-Ge alloys are promising, low cost, high performance candidates for magnetic cooling applications based on the magnetocaloric effect. These alloys undergo a magnetic phase transition which induces a large entropy change (ΔS). Experimental and modeling studies were conducted to study this transition for varying Ge content. Landau theory and the Bean-Rodbell model were applied to Mn1.1Fe0.9P1−xGex (x = 0.26, 0.3, and 0.32) melt spun ribbons to model the phase transition and the associated entropy change. The critical behavior of these alloys was studied. The critical composition range at which the cross over from first order to second order magnetic transition occurs was determined. The calculated thermodynamic values and critical temperatures were in good agreement with our experimental results. A high maximum entropy change (ΔS) of ∼44.9 J kg−1 K−1 was observed in Mn1.1Fe0.9P0.74Ge0.26 in a 5 T applied magnetic field. The results suggest that Mn-Fe-P-Ge alloys are very attractive materials for near room temperature magnetic cooling.
Inverse problems for selfadjoint Schrödinger operators on the half line with compactly supported potentials
Authors: Aktosun Tuncay , Sacks Paul , Unlu Mehmet
Published: February 2015

For a selfadjoint Schrödinger operator on the half line with a real-valued, integrable, and compactly supported potential, it is investigated whether the boundary parameter at the origin and the potential can uniquely be determined by the scattering matrix or by the absolute value of the Jost function known at positive energies, without having the bound-state information. It is proved that, except in one special case where the scattering matrix has no bound states and its value is +1 at zero energy, the determination by the scattering matrix is unique. In the special case, it is shown that there are exactly two distinct sets consisting of a potential and a boundary parameter yielding the same scattering matrix, and a characterization of the nonuniqueness is provided. A reconstruction from the scattering matrix is outlined yielding all the corresponding potentials and boundary parameters. The concept of “eligible resonances” is introduced, and such resonances correspond to real-energy resonances that can be converted into bound states via a Darboux transformation without changing the compact support of the potential. It is proved that the determination of the boundary parameter and the potential by the absolute value of the Jost function is unique up to the inclusion of eligible resonances. Several equivalent characterizations are provided to determine whether a resonance is eligible or ineligible. A reconstruction from the absolute value of the Jost function is given, yielding all the corresponding potentials and boundary parameters. The results obtained are illustrated with various explicit examples.
Electric and geometric controlling of the magnetic coupling in Kane-Mele nanoribbons
Authors: Bao Weicheng , Zou Liang-Jian , Lin H.-Q.
Published: February 2015

In this paper, we show that indirect spin interaction J between two magnetic impurities located on honeycomb Kane-Mele zigzag/armchair ribbons (KMZR/KMAR) is easily controlled by staggered potential and geometry. We demonstrate that J in periodic-boundary KMZR reaches maximum at the edges, and oscillates between antiferromagnetic and ferromagnetic couplings when tuning the sublattice staggered potential Δ. The odd-even length effect of J in KMZR and the width dependence of J in KMAR are also presented. These results clearly demonstrate the unique role of topological edge states and finite-size effect in magnetic coupling of quantum spin Hall (QSH) ribbons, and the controllability of the edge magnetism, hence favoring the fabrication of the spintronic devices in two-dimensional buckled honeycomb materials, e.g., silicene and germanene.
Two-photon absorption cross sections within equation-of-motion coupled-cluster formalism using resolution-of-the-identity and Cholesky decomposition representations: Theory, implementation, and benchmarks
Authors: Nanda Kaushik D. , Krylov Anna I.
Published: February 2015

The equation-of-motion coupled-cluster (EOM-CC) methods provide a robust description of electronically excited states and their properties. Here, we present a formalism for two-photon absorption (2PA) cross sections for the equation-of-motion for excitation energies CC with single and double substitutions (EOM-CC for electronically excited states with single and double substitutions) wave functions. Rather than the response theory formulation, we employ the expectation-value approach which is commonly used within EOM-CC, configuration interaction, and algebraic diagrammatic construction frameworks. In addition to canonical implementation, we also exploit resolution-of-the-identity (RI) and Cholesky decomposition (CD) for the electron-repulsion integrals to reduce memory requirements and to increase parallel efficiency. The new methods are benchmarked against the CCSD and CC3 response theories for several small molecules. We found that the expectation-value 2PA cross sections are within 5% from the quadratic response CCSD values. The RI and CD approximations lead to small errors relative to the canonical implementation (less than 4%) while affording computational savings. RI/CD successfully address the well-known issue of large basis set requirements for 2PA cross sections calculations. The capabilities of the new code are illustrated by calculations of the 2PA cross sections for model chromophores of the photoactive yellow and green fluorescent proteins.
The growth of sulfur adlayers on Au(100)
Authors: Jiang Yue , Liang Xihui , Ren Shendong , Chen Chi-Lu , Fan Liang-Jen , Yang Yaw-Wen , Tang Jian-Ming , Luh Dah-An
Published: February 2015

We have studied the growth of S layers adsorbed on Au(100) with low-energy electron diffraction (LEED), X-ray photoemission spectra (XPS), and scanning tunneling microscope (STM). Three phases of S/Au(100)—(2 × 2), trimer, and c(2 × 4)—are identified; the latter two are not previously reported. A dose of S2 at 300 K transformed Au(100)-(5 × 20) initially into the (2 × 2) phase and formed the c(2 × 4) phase at a saturation coverage. The STM results show that monolayer Au islands formed during the initial S dose and remained throughout the growth, resulting in a rough c(2 × 4) surface. We show that a highly ordered c(2 × 4) phase can be obtained with a flat (2 × 2) phase as an intermediate step during growth. Based on the evolution of XPS and STM images with varied S2 dose, the components of S 2p are assigned and structural models for the various S/Au(100) phases are proposed. In the (2 × 2) phase, one S atom resides on a four-fold hollow site in each (2 × 2) unit cell, corresponding to a S coverage of 0.25 ML; in the trimer phase, three S atoms form a trimer residing on a four-fold hollow site in each (2 × 2) unit cell, corresponding to a S coverage of 0.75 ML; in the c(2 × 4) phase, there are five S atoms in each primitive unit cell of c(2 × 4); three of them form a trimer residing on a four-fold hollow site, and the other two form a dimer located on the top of the trimer, corresponding to a nominal S coverage of 1.25 ML. With the proposed structural models, the growth of S on Au(100) at 300 K is described in detail.
A flux extraction device to measure the magnetic moment of large samples; application to bulk superconductors
Authors: Egan R. , Philippe M. , Wera L. , Fagnard J. F. , Vanderheyden B. , Dennis A. , Shi Y. , Cardwell D. A. , Vanderbemden P.
Published: February 2015

We report the design and construction of a flux extraction device to measure the DC magnetic moment of large samples (i.e., several cm3) at cryogenic temperature. The signal is constructed by integrating the electromotive force generated by two coils wound in series-opposition that move around the sample. We show that an octupole expansion of the magnetic vector potential can be used conveniently to treat near-field effects for this geometrical configuration. The resulting expansion is tested for the case of a large, permanently magnetized, type-II superconducting sample. The dimensions of the sensing coils are determined in such a way that the measurement is influenced by the dipole magnetic moment of the sample and not by moments of higher order, within user-determined upper bounds. The device, which is able to measure magnetic moments in excess of 1 A m2 (1000 emu), is validated by (i) a direct calibration experiment using a small coil driven by a known current and (ii) by comparison with the results of numerical calculations obtained previously using a flux measurement technique. The sensitivity of the device is demonstrated by the measurement of flux-creep relaxation of the magnetization in a large bulk superconductor sample at liquid nitrogen temperature (77 K).
Dissociative electron attachments to ethanol and acetaldehyde: A combined experimental and simulation study
Authors: Wang Xu-Dong , Xuan Chuan-Jin , Feng Wen-Ling , Tian Shan Xi
Published: February 2015

Dissociation dynamics of the temporary negative ions of ethanol and acetaldehyde formed by the low-energy electron attachments is investigated by using the anion velocity map imaging technique and ab initio molecular dynamics simulations. The momentum images of the dominant fragments O−/OH− and CH3− are recorded, indicating the low kinetic energies of O−/OH− for ethanol while the low and high kinetic energy distributions of O− ions for acetaldehyde. The CH3− image for acetaldehyde also shows the low kinetic energy. With help of the dynamics simulations, the fragmentation processes are qualitatively clarified. A new cascade dissociation pathway to produce the slow O− ion via the dehydrogenated intermediate, CH3CHO− (acetaldehyde anion), is proposed for the dissociative electron attachment to ethanol. After the electron attachment to acetaldehyde molecule, the slow CH3− is produced quickly in the two-body dissociation with the internal energy redistributions in different aspects before bond cleavages.
Determination of the thermal diffusivity of bulk and layered samples by time domain thermoreflectance: Interest of lateral heat diffusion investigation in nanoscale time range
Authors: Belliard L. , Frétigny C. , Charron E. , Vincent S. , Perrin B. , Fournier D.
Published: February 2015

We report on thermal investigations performed in a time resolved experimental scheme. The time domain thermoreflectance (TDTR) is applied in an unusual geometry where the pump and probe beams are not superimposed but focused and shifted. In this way, the determination of the in-plane thermal diffusivity is achieved from temperature snapshots at different time delays. In the first part, taking into account the specific generation process and the detection inherent to the time domain thermoreflectance approach, an analytical solution for the temperature field is obtained for bulk samples, and compared to experimental data. A comparison with the frequency domain thermoreflectance microscopy is also outlined. In Part II section, the lateral heat diffusion in a layered structure is investigated. The comparison of the heat diffusion spreading in case of a highly conductive layer deposited on an insulator substrate and the reverse situation are carefully studied. Finally, we show how the time dependence is efficient to probe and identify material thermal properties or thermal interfacial resistance.
Direct observation of charge mediated lattice distortions in complex oxide solid solutions
Authors: Sang Xiahan , Grimley Everett D. , Niu Changning , Irving Douglas L. , LeBeau James M.
Published: February 2015

Using aberration corrected scanning transmission electron microscopy combined with advanced imaging methods, we directly observe atom column specific, picometer-scale displacements induced by local chemistry in a complex oxide solid solution. Displacements predicted from density functional theory were found to correlate with the observed experimental trends. Further analysis of bonding and charge distribution was used to clarify the mechanisms responsible for the detected structural behavior. By extending the experimental electron microscopy measurements to previously inaccessible length scales, we identified correlated atomic displacements linked to bond differences within the complex oxide structure.
Dynamics of laser induced metal nanoparticle and pattern formation
Authors: Peláez R. J. , Kuhn T. , Rodríguez C. E. , Afonso C. N.
Published: February 2015

Discontinuous metal films are converted into either almost round, isolated, and randomly distributed nanoparticles (NPs) or fringed patterns of alternate non transformed film and NPs by exposure to single pulses (20 ns pulse duration and 193 nm wavelength) of homogeneous or modulated laser beam intensity. The dynamics of NPs and pattern formation is studied by measuring in real time the transmission and reflectivity of the sample upon homogeneous beam exposure and the intensity of the diffraction orders 0 and 1 in transmission configuration upon modulated beam exposure. The results show that laser irradiation induces melting of the metal either completely or at regions around intensity maxima sites for homogeneous and modulated beam exposure, respectively, within ≤10 ns. The aggregation and/or coalescence of the initially irregular metal nanostructures is triggered upon melting and continues after solidification (estimated to occur at ≤80 ns) for more than 1 μs. The present results demonstrate that real time transmission rather than reflectivity measurements is a valuable and easy-to-use tool for following the dynamics of NPs and pattern formation. They provide insights on the heat-driven processes occurring both in liquid and solid phases and allow controlling in-situ the process through the fluence. They also evidence that there is negligible lateral heat release in discontinuous films upon laser irradiation.
Origin and turbulence spreading of plasma blobs
Authors: Manz P. , Ribeiro T. T. , Scott B. D. , Birkenmeier G. , Carralero D. , Fuchert G. , Müller S. H. , Müller H. W. , Stroth U. , Wolfrum E.
Published: February 2015

The formation of plasma blobs is studied by analyzing their trajectories in a gyrofluid simulation in the vicinity of the separatrix. Most blobs arise at the maximum radial electric field outside the separatrix. In general, blob generation is not bound to one particular radial position or instability. A simple model of turbulence spreading for the scrape-off layer is derived. The simulations show that the blob dynamics can be represented by turbulence spreading, which constitutes a substantial energy drive for far scrape-off layer turbulence and is a more suitable quantity to study blob generation compared to the skewness.
Cadmium zinc telluride based infrared interferometry for X-ray detection
Authors: Lohstroh A. , Della Rocca I. , Parsons S. , Langley A. , Shenton-Taylor C. , Blackie D.
Published: February 2015

Cadmium Zinc Telluride (CZT) is a wide band gap semiconductor for room temperature radiation detection. The electro-optic Pockels effect of the material has been exploited in the past to study electric field non-uniformities and their consequence on conventional detector signals in CZT, by imaging the intensity distribution of infrared (IR) light transmitted through a device placed between crossed polarizers. Recently, quantitative monitoring of extremely high intensity neutron pulses through the change of transmitted IR intensity was demonstrated, offering the advantage to place sensitive electronics outside the measured radiation field. In this work, we demonstrate that X-ray intensity can be deduced directly from measuring the change in phase of 1550 nm laser light transmitted through a 7 × 7 × 2 mm3 CZT based Pockels cell in a simple Mach Zehnder interferometer. X-rays produced by a 50 kVp Mo X-ray tube incident on the CZT cathode surface placed at 7 mm distance cause a linearly increasing phase shift above 0.3 mA tube current, with 1.58 ± 0.02 rad per mA for an applied bias of 500 V across the 2 mm thick device. Pockels images confirm that the sample properties are in agreement with the literature, exhibiting electric field enhancement near the cathode under irradiation, which may cause the non-linearity at low X-ray tube anode current settings. The laser used to probe the X-ray intensity causes itself some space charge, whose spatial distribution does not seem to be exclusively determined by the incident laser position, i.e., charge carrier generation location, with respect to the electrodes.
Multifunctional oxides for integrated manufacturing of efficient graphene electrodes for organic electronics
Authors: Kidambi Piran R. , Weijtens Christ , Robertson John , Hofmann Stephan , Meyer Jens
Published: February 2015

Using multi-functional oxide films, we report on the development of an integration strategy for scalable manufacturing of graphene-based transparent conducting electrodes (TCEs) for organic electronics. A number of fundamental and process challenges exists for efficient graphene-based TCEs, in particular, environmentally and thermally stable doping, interfacial band engineering for efficient charge injection/extraction, effective wetting, and process compatibility including masking and patterning. Here, we show that all of these challenges can be effectively addressed at once by coating graphene with a thin (>10 nm) metal oxide (MoO3 or WO3) layer. We demonstrate graphene electrode patterning without the need for conventional lithography and thereby achieve organic light emitting diodes with efficiencies exceeding those of standard indium tin oxide reference devices.
A compact J-V model for solar cell to simplify parameter calculation
Authors: Dash D. P. , Roshan Rakesh , Mahata Shrabani , Mallik S. , Mahato S. S. , Sarkar S. K.
Published: February 2015

For practical solar cells, the J-V (Current-Voltage) equation is quiet implicit to calculate the fill factor and maximum power point through enormous iterative calculations. Here, a new compact model is proposed that is pertinent with different solar cells. Only three model parameters are used to analyse the effectiveness of the model. Compared to other complex implicit models, it does not require iterative calculations for parameter extraction. The effects like space charge leakage current, trapping, tunneling, etc., are reflected in the first term of the model and the second represents the degradation in current due to shunt resistance. It satisfies wide varieties of solar cells with remarkable accuracy as well as parameters are extracted using four points on J-V characteristics only. The model is well compared with experimental characteristics taken from published literatures.
A novel synthesis of tin oxide thin films by the sol-gel process for optoelectronic applications
Authors: Marikkannan M. , Vishnukanthan V. , Vijayshankar A. , Mayandi J. , Pearce J. M.
Published: February 2015

A novel and simple chemical method based on sol-gel processing was proposed to deposit metastable orthorhombic tin oxide (SnOx) thin films on glass substrates at room temperature. The resultant samples are labeled according to the solvents used: ethanol (SnO-EtOH), isopropanol (SnO-IPA) and methanol (SnO-MeOH). The variations in the structural, morphological and optical properties of the thin films deposited using different solvents were characterized by X-ray diffraction, atomic force microscopy, Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, UV-vis spectroscopy and photoluminescence (PL) analysis. The XRD patterns confirm that all the films, irrespective of the solvents used for preparation, were polycrystalline in nature and contained a mixed phases of tin (II) oxide and tin (IV) oxide in a metastable orthorhombic crystal structure. FTIR spectra confirmed the presence of Sn=O and Sn-O in all of the samples. PL spectra showed a violet emission band centered at 380 nm (3.25 eV) for all of the solvents. The UV-vis spectra indicated a maximum absorption band shown at 332 nm and the highest average transmittance around 97% was observed for the SnO-IPA and SnO-MeOH thin film samples. The AFM results show variations in the grain size with solvent. The structural and optical properties of the SnO thin films indicate that this method of fabricating tin oxide is promising and that future work is warranted to analyze the electrical properties of the films in order to determine the viability of these films for various transparent conducting oxide applications.
Population characteristics and management of the long-nosed potoroo (Potorous tridactylus) in high-quality habitat in the Southern Highlands of New South Wales
Authors: Norton Melinda A. , Prentice Alison , Dingle Juliet , French Kris , Claridge Andrew W.
Published: February 2015

Since European settlement in Australia the long-nosed potoroo (Potorous tridactylus) has suffered greatly from fox predation and habitat loss, fragmentation and degradation. To better understand the threats it faces we examined the population dynamics of the potoroo at two study sites in the Southern Highlands of New South Wales over five years, using live-trapping. As neither site had experienced inappropriate habitat change for over 25 years, fox predation was considered the major threat to this population. An assessment of fox activity and diet was undertaken at both sites for comparison with potoroo abundance. Potoroos increased at both sites over time, although at one site this increase was only in density and not range. The density increase would not have been detected using camera surveys, a monitoring technique recommended for this species. The relative abundance of foxes fluctuated over the study despite fox control in one of the two sites. Analysis of fox scats at the same sites indicated high levels of predation on potoroos. Future management should aim to provide effective fox control (particularly following any fire due to the associated loss of ground cover) and improved fox monitoring to ensure an accurate understanding of what is happening to the fox population.
Interspecific variation in branch and leaf traits among three Syzygium tree species from different successional tropical forests
Authors: Zhu Shi-Dan , Chen Ya-Jun , Cao Kun-Fang , Ye Qing
Published: February 2015

Plant functional traits are closely associated with plant habitats. In this study, we investigated the interspecific variations in stem and leaf hydraulics, xylem and leaf anatomy, gas-exchange rates and leaf pressure–volume relationships among three Syzygium tree species in early, mid- and late successional tropical forests. The objective was to understand the response and adaptation of congeneric species, in terms of branch and leaf functional traits, to different environments. A consistent pattern of decline with succession was evident in leaf and sapwood specific hydraulic conductivity (ks), maximum leaf hydraulic conductance (Kleaf), and photosynthetic rates for the three Syzygium species. Variations of ks and Kleaf were correlated with changes in vessel anatomy (i.e. vessel density and diameter) and leaf flux-related structure (i.e. stomatal pore index and vein density) respectively. However, specific leaf area and leaf to sapwood area ratio did not significantly differ among the three species. In addition, the mid-successional species had the lowest values of leaf water potential at full turgor and turgor loss point and 50% loss of Kleaf, but the greatest value of xylem water potential at 50% loss of ks. Our results demonstrate that leaf and branch traits associated with photosynthesis and/or hydraulic conductance, rather than those associated with drought tolerance, are the key factors underlying the response and adaptation of the three Syzygium tree species along the tropical forest succession.
Dexamethasone treatment of pregnant F0 mice leads to parent of origin-specific changes in placental function of the F2 generation
Authors: Vaughan O. R. , Phillips H. M. , Everden A. J. , Sferruzzi-Perri A. N. , Fowden A. L.
Published: February 2015

Dexamethasone treatment of F0 pregnant rodents alters F1 placental function and adult cardiometabolic phenotype. The adult phenotype is transmitted to the F2 generation without further intervention, but whether F2 placental function is altered by F0 dexamethasone treatment remains unknown. In the present study, F0 mice were untreated or received dexamethasone (0.2 µg g–1 day–1, s.c.) over Days 11–15 or 14–18 of pregnancy (term Day 21). Depending on the period of F0 dexamethasone treatment, F1 offspring were lighter at birth or grew more slowly until weaning (P < 0.05). Glucose tolerance (1 g kg–1, i.p.) of adult F1 males was abnormal. Mating F1 males exposed prenatally to dexamethasone with untreated females had no effect on F2 placental function on Day 19 of pregnancy. In contrast, when F1 females were mated with untreated males, F2 placental clearance of the amino acid analogue 14C-methylaminoisobutyric acid was increased by 75% on Day 19 specifically in dams prenatally exposed to dexamethasone on Days 14–18 (P < 0.05). Maternal plasma corticosterone was also increased, but F2 placental Slc38a4 expression was decreased in these dams (P < 0.05). F0 dexamethasone treatment had no effect on F2 fetal or placental weights, regardless of lineage. Therefore, the effects of F0 dexamethasone exposure are transmitted intergenerationally to the F2 placenta via the maternal, but not paternal, line.
Stereo Disparity Facilitates View Generalization during Shape Recognition for Solid Multipart Objects
Authors: Cristino Filipe , Davitt Lina , Hayward William G. , Leek E. Charles
Published: February 2015

Current theories of object recognition in human vision make different predictions about whether the recognition of complex, multipart objects should be influenced by shape information about surface depth orientation and curvature derived from stereo disparity. We examined this issue in five experiments using a recognition memory paradigm in which observers ( N = 134) memorized and then discriminated sets of 3D novel objects at trained and untrained viewpoints under either mono or stereo viewing conditions. In order to explore the conditions under which stereo-defined shape information contributes to object recognition we systematically varied the difficulty of view generalization by increasing the angular disparity between trained and untrained views. In one series of experiments, objects were presented from either previously trained views or untrained views rotated (15°, 30°, or 60°) along the same plane. In separate experiments we examined whether view generalization effects interacted with the vertical or horizontal plane of object rotation across 40° viewpoint changes. The results showed robust viewpoint-dependent performance costs: Observers were more efficient in recognizing learned objects from trained than from untrained views, and recognition was worse for extrapolated than for interpolated untrained views. We also found that performance was enhanced by stereo viewing but only at larger angular disparities between trained and untrained views. These findings show that object recognition is not based solely on 2D image information but that it can be facilitated by shape information derived from stereo disparity.
Tailoring metal–organic hybrid interfaces: heteromolecular structures with varying stoichiometry on Ag(111)
Authors: Stadtmüller Benjamin , Henneke Caroline , Soubatch Serguei , Tautz F Stefan , Kumpf Christian
Published: February 2015

The physical properties of interfaces between organic semiconductors and metal surfaces crucially influence the performance of organic electronic devices. In order to enable the tailoring of such metal–organic hybrid interfaces we study the adsorption of heteromolecular thin films containing the prototypical molecules copper-II-phthalocyanine (CuPc) and 3,4,9,10-perylene-tetra-carboxylic-dianhydride (PTCDA) on the Ag(111) surface. Here, we demonstrate how the lateral order can be tuned by changing the relative coverage of both adsorbates on the surface. The layer growth has been studied in real time with low energy electron microscopy, and—for different stoichiometries—the geometric properties of three heteromolecular submonolayer phases have been investigated using high resolution low energy electron diffraction and low temperature scanning tunneling microscopy. Furthermore, we have used a theoretical approach based on van der Waals and electrostatic potentials in order to reveal the influence of the intermolecular and the molecule–substrate interactions on the lateral order of heteromolecular films.
Mean curvature flow of Killing graphs
Authors: Lira J. , Wanderley G.
Published: February 2015

We study a Neumann problem related to the evolution of graphs under mean curvature flow in Riemannian manifolds endowed with a Killing vector field. We prove that in a particular case these graphs converge to a trivial minimal graph which contacts the cylinder over the domain orthogonally along its boundary.