bluuebunny/crossref_metadata_2025 huggingface dataset:
The kinetics and mechanism of nanoconfined molten salt reactions: trimerization of potassium and rubidium dicyanamide
Authors: Yancey Benjamin , Vyazovkin Sergey
Published: March 2015

Nanoconfinement accelerates the liquid state trimerization of potassium and rubidium dicyanamide but decelerates the solid state trimerization of sodium dicyanamide.
Correction: Strategies to create hierarchical self-assembled structures via cooperative non-covalent interactions
Authors: Rest Christina , Kandanelli Ramesh , Fernández Gustavo
Published: March 2015

Correction for ‘Strategies to create hierarchical self-assembled structures via cooperative non-covalent interactions’ by Christina Rest et al., Chem. Soc. Rev., 2015, DOI: 10.1039/c4cs00497c.
Long-lived luminescent soft materials of hexanitratosamarate(iii) complexes with orange visible emission
Authors: Tang Ning , Zhao Ying , He Ling , Yuan Wen-Li , Tao Guo-Hong
Published: March 2015

Novel hexanitratosamarate ionic liquids display orange luminescent emission and are of interest as potential luminescent soft materials that have a long lifetime.
Synthesis, characterization, photophysics, and anion binding properties of platinum(ii) acetylide complexes with urea group
Authors: Zhang Zhi-Hui , Liu Jiewei , Wan Li-Qi , Jiang Fang-Ru , Lam Chi-Keung , Ye Bao-Hui , Qiao Zhengping , Chao Hsiu-Yi
Published: March 2015

The relationship between the structure and anion-binding ability of platinum(ii) acetylide complexes with urea group has been studied.
Pharmacological activity of metal binding agents that alter copper bioavailability
Authors: Helsel Marian E. , Franz Katherine J.
Published: March 2015

An exploration of synthetic metal-binding agents that alter the bioavailability of copper in ways that may provide therapeutic benefit against neurodegenerative diseases, cancer, infection, and other diseases where misappropriated metal ions are suspected of exacerbating cellular damage.
Spatially-confined lithiation–delithiation in highly dense nanocomposite anodes towards advanced lithium-ion batteries
Authors: Jiang Yinzhu , Li Yong , Sun Wenping , Huang Wei , Liu Jiabin , Xu Ben , Jin Chuanhong , Ma Tianyu , Wu Changzheng , Yan Mi
Published: March 2015

Spatially-confined electrochemical reactions are firstly realized in a highly dense nanocomposite anode for high performance lithium ion batteries.
Magnetic nanoparticle supports for asymmetric catalysts
Authors: Dalpozzo Renato
Published: March 2015

The introduction of magnetic nanoparticles (MNPs) has favoured the recovery of organocatalysts for asymmetric catalysis with techniques of magnetic separation.
The gadolinium-based contrast agent Omniscan® promotes in vitro fibroblast survival through in situ precipitation
Authors: Feng Min , Fan Yun-Zhou , Ma Xiao-Jie , Li Jin-Xia , Yang Xiao-Gai
Published: March 2015

The current study aims to explore how the gadolinium (Gd)-based contrast agent (GBCA) Omniscan® enhanced cell viability of murine fibroblasts. The results of scanning electron microscopy showed that Omniscan® can precipitate in cell culture media and deposit on cell membranes. Energy-dispersive X-ray analysis and Fourier-transform infrared spectroscopy demonstrated the presence of Gd and phosphates in the agglomerated particles. By filtering the Omniscan®-containing medium through a 220 nm filter, it can be clearly found that the increased cell viability should be mainly attributed to the insoluble species of gadolinium rather than to chelated gadolinium. Moreover, the effects of other gadolinium-based contrast agents, Magnevist® and Dotarem®, were compared with that of Omniscan®. It is noted that the three contrast agents differed in their ability to induce cell viability, which is possibly ascribed to the different chemical stabilities of gadolinium chelates as demonstrated by the attenuation in cell growth upon the addition of excess ligands to the compounds. The results of flow cytometry analysis also showed that Omniscan® can promote cell growth via an increase in the S-phase cell population as evidenced by the elevated levels of cell cycle associated proteins cyclin D, cyclin A and the phosphorylated Rb protein. Furthermore, our results revealed that integrin-mediated signaling may play an important role in both Omniscan® and Magnevist®-enhanced focal adhesion formation since the blockade of integrins decreased the level of ERK phosphorylation induced by the two GBCAs. Taken together, these data suggested that in situ gadolinium phosphate precipitation formation mediated Omniscan®-promoted fibroblast survival, which is similar to that of gadolinium chloride. It was demonstrated that the application of GBCAs with more stable thermodynamic stability may cause less dissociation of the gadolinium ion and thus resulted in less precipitation, finally leading to lower occurrence of nephrogenic systemic fibrosis. The obtained results would also be helpful for the development of safe gadolinium-based contrast agents.
Kinetics and equilibrium studies on the removal of aromatic sulfonates from aqueous solution by Mg–Al oxide
Authors: Kameda Tomohito , Umetsu Mami , Yoshioka Toshiaki
Published: March 2015

Both (a) benzenesulfonate and (b) 2-naphthalenesulfonate intercalated in the Mg–Al LDH tend to orient perpendicularly as concentration increases.
Thick solid electrolyte interphases grown on silicon nanocone anodes during slow cycling and their negative effects on the performance of Li-ion batteries
Authors: Luo Fei , Chu Geng , Xia Xiaoxiang , Liu Bonan , Zheng Jieyun , Li Junjie , Li Hong , Gu Changzhi , Chen Liquan
Published: March 2015

A 5 μm thick SEI can be formed on Si nanocone electrodes at a low rate in lithium batteries.
Taking a hard line with biotemplating: cobalt-doped magnetite magnetic nanoparticle arrays
Authors: Bird Scott M. , Galloway Johanna M. , Rawlings Andrea E. , Bramble Jonathan P. , Staniland Sarah S.
Published: March 2015

A cysteine-mutated biomineralisation protein (Mms6) patterned onto gold biotemplates magnetic nanoparticle arrays of magnetite and higher coercivity cobalt-doped magnetite. This demonstrates an adaptable, green approach for the future of nanofabrication.
Si microstructures laminated with a nanolayer of TiO2 as long-term stable and effective photocathodes in PEC devices
Authors: Das Chittaranjan , Tallarida Massimo , Schmeisser Dieter
Published: March 2015

Photoelectrochemical (PEC) water splitting is one of the most emerging fields for green energy generation and storage.
Au-catalyzed ring-opening reactions of 2-(1-alkynyl-cyclopropyl)pyridines with nucleophiles
Authors: Liu Ren-Rong , Ye Shi-Chun , Lu Chuan-Jun , Xiang Bin , Gao Jianrong , Jia Yi-Xia
Published: March 2015

A novel method for the C–C bond cleavage of cyclopropanes was developed by gold-catalyzed cycloisomerization of 2-(1-alkynyl-cyclopropyl)pyridine with nucleophiles, which provides efficient access to structurally diverse indolizines under mild conditions.
Unraveling the forming mechanism of hierarchical helices via self-assembly of an achiral supramolecular polymer brush
Authors: Liu Shanshan , Chen Qibin , Sheng Yujie , Shen Jincheng , Peng Changjun , Liu Honglai
Published: March 2015

We propose a detailed structural transition of the hierarchical helix or superhelix of PVP–PDP from straightforward experimental evidence.
Thiol–maleimide “click” chemistry: evaluating the influence of solvent, initiator, and thiol on the reaction mechanism, kinetics, and selectivity
Authors: Northrop Brian H. , Frayne Stephen H. , Choudhary Umesh
Published: March 2015

The mechanism and kinetics of thiol–maleimide “click” reactions have been modeled computationally under a variety of conditions and further investigated using experimental competition reactions.
Synthesis and properties of temperature-sensitive and chemically crosslinkable poly(ether-urethane) hydrogel
Authors: Li Ruizhi , Liu Na , Li Bingqiang , Wang Yinong , Wu Guolin , Ma Jianbiao
Published: March 2015

The PEU-MA solutions can gelate at physiological temperature, and be further crosslinked by UV light.
Antimicrobial polymethacrylates based on quaternized 1,3-thiazole and 1,2,3-triazole side-chain groups
Authors: Tejero Rubén , López Daniel , López-Fabal Fátima , Gómez-Garcés José L. , Fernández-García Marta
Published: March 2015

Increasing antimicrobial and non-hemotoxic characteristics of polymers bearing thiazole and triazole groups by the appropriate selection of spacer and quaternization groups.
New poly(selenophene–thiophene) bearing π-conjugating spacers for polymer field-effect transistors and photovoltaic cells
Authors: Chiu Chi-Chou , Wu Hung-Chin , Lu Chien , Chen Jung-Yao , Chen Wen-Chang
Published: March 2015

Five new poly(selenophene–thiophene) were synthesized for polymer optoelectronic applications. The hole field effect mobility and polymer photovoltaic power conversion efficiency could be as high as 0.27 cm2 V−1 s−1 and 2.3 %, respectively.
A one-pot dilithiation–lithium–zinc exchange–Negishi coupling approach to 2,6-di(hetero)aryl substituted dithienothiazines – a novel class of electronically fine-tunable redox systems
Authors: Dostert Catherine , Müller Thomas J. J.
Published: March 2015

2,6-Di(hetero)aryl substituted dithienothiazines with fine-tunable electronic properties are efficiently accessible by lithiation–lithium–zinc exchange–Negishi cross-coupling in a one-pot fashion.
Self-template synthesis of CoFe2O4nanotubes for high-performance lithium storage
Authors: Zhang Xiao , Xie Yaping , Sun Yanfang , Zhang Qiao , Zhu Qiuyu , Hou Dan , Guo Jinxue
Published: March 2015

CoFe2O4nanotubes synthesizedviaself-templated strategy based on the Kirkendall effect show large and stable reversible capacity superior high-rate capability, durable cycling life and good capacity retention.
Lanthanide cation-induced tuning of surface capping properties in zinc sulfide nanoparticles: an infrared absorption study
Authors: Ghatak Ankita , Debnath Gouranga H. , Mandal Madhuri , Mukherjee Prasun
Published: March 2015

Lanthanide cations tune the infrared absorption characteristics of the capping ligands in Zn(Ln)S [Ln = Sm, Eu, Tb, Dy] nanoparticles.
Green synthesized silver nanoparticles decorated on reduced graphene oxide for enhanced electrochemical sensing of nitrobenzene in waste water samples
Authors: Karuppiah Chelladurai , Muthupandi K. , Chen Shen-Ming , Ali M. Ajmal , Palanisamy Selvakumar , Rajan A. , Prakash P. , Al-Hemaid Fahad M. A. , Lou Bih-Show
Published: March 2015

In the present work, an electrochemical sensor for nitrobenzene has been developed based on a green synthesized silver nanoparticle (AgNP) decorated reduced graphene oxide (RGO) modified glassy carbon electrode (GCE).
The effect of ring sizes and alkali metal cations on interaction energy, charge transfer and nonlinear optical properties of crown ether derivatives
Authors: Gao Ying , Zhong Rong-Lin , Xu Hong-Liang , Sun Shi-Ling , Su Zhong-Min
Published: March 2015

A series of the crown ethers are designed to explore the effect of ring sizes and the nature of alkali metal cations doping on the interaction energy, charge transfer and nonlinear optical property.
Encapsulation of doxorubicin within multifunctional gadolinium-loaded dendrimer nanocomplexes for targeted theranostics of cancer cells
Authors: Zhu Jingyi , Xiong Zhijuan , Shen Mingwu , Shi Xiangyang
Published: March 2015

Multifunctional gadolinium-loaded dendrimer nanocomplexes can be used to encapsulate doxorubicin for targeted magnetic resonance imaging and chemotherapy of cancer cells.
The band gap modulation of monolayer Ti2CO2 by strain
Authors: Yu Xue-fang , Cheng Jian-bo , Liu Zhen-bo , Li Qing-zhong , Li Wen-zuo , Yang Xin , Xiao Bo
Published: March 2015

Monolayer Ti2CO2: indirect–direct band gap transition under biaxial strain of ∼4% and uniaxial strain of ∼6%.
Facile reduction of aromatic nitro compounds to aromatic amines catalysed by support-free nanoporous silver
Authors: Li Zhiwen , Xu Xiaohong , Jiang Xiaojian , Li Yingchun , Yu Zhixin , Zhang Xiaomei
Published: March 2015

Reduction of aromatic nitro compounds to aromatic amines was realized in excellent yields by using nanoporous silver as a sustainable, heterogeneous catalyst.
The co-adsorption of Cu2+ and Zn2+ with adsorption sites surface-lattice reforming on calcined layered double hydroxides
Authors: Xiao Yuxin , Sun Mingming , Zhang Lin , Gao Xue , Su Jixin , Zhu Hong
Published: March 2015

The picture shows that how the CLDHs recover into the hydrotalcite structure in the process of adsorption of Cu2+ and Zn2+.
Modification of PEG-b-PCL block copolymer with high melting temperature by the enhancement of POSS crystal and ordered phase structure
Authors: Yin Guangzhong , Chen Guangxin , Zhou Zheng , Li Qifang
Published: March 2015

Alkyne-functionalized polyhedral oligomeric silsesquioxane was successfully prepared and further used to modify PEG-b-PCL via click chemistry, resulting in a successful synthesis of POSS grafted PEG-b-PCL.
Structure and hydrothermal stability of highly oriented polyamide 6 produced by solid hot stretching
Authors: Shi Kaihua , Ye Lin , Li Guangxian
Published: March 2015

The effect of orientation on the structure and hydrothermal stability of PA6 was investigated. The stable dense crystalline structure with α crystal form formed by molecular orientation contributed to slowing down the hydrolysis degradation of PA6.
Facile synthesis of meso-porous ZnO nano-triangular prisms with enhanced photocatalytic activity
Authors: Vignesh K. , Kang Sora , Kwak Byeong Sub , Kang Misook
Published: March 2015

A schematic diagram of the electron–hole transfer process in ZnO-nt under simulated solar light irradiation.
A silica nanoparticle supported fluorescence “turn-on” fluoride ion sensing system with tunable structure and sensitivity
Authors: Appiah-Ntiamoah Richard , Jadhav Arvind H. , Puguan John. Marc. C. , Momade Francis W. Y. , Kim Hern
Published: March 2015

The emission spectra of sensor B was 3 fold that of sensor A at F− and FITC-OSMDBT mole equivalent ratio of x : x (x = 3, 6, and 9).
The effect of carbon black in carbon counter electrode for CH3NH3PbI3/TiO2 heterojunction solar cells
Authors: Wang Heng , Hu Xiaoyan , Chen Hongxia
Published: March 2015

The effects of carbon black on the performance of perovskite solar cells with carbon counter electrode were systematically investigated.
A fast and selective probe for detection of CN− and F− in water along with a sequential molecular logic circuit via resettable optical readout
Authors: Singh Alok Kumar
Published: March 2015

A fast and selective probe for detection of CN− and F− at ppm levels in water via multiple readout for precise analysis.
Extractive desulfurization of fuel using N-butylpyridinium-based ionic liquids
Authors: Gao Hongshuai , Zeng Shaojuan , Liu Xiaomin , Nie Yi , Zhang Xiangping , Zhang Suojiang
Published: March 2015

Sulfur compounds in fuels have become one of the sources of serious environmental problems.
New binuclear copper(ii) coordination polymer based on mixed pyrazolic and oxalate ligands: structural characterization and mechanical properties
Authors: López Marzo Adaris M. , Guerrero Miguel , Calvet Teresa , Font-Bardia Mercè , Pellicer Eva , Baró Maria Dolors , Pons Josefina , Sort Jordi
Published: March 2015

A new inorganic–organic coordination polymer based on a copper(ii) binuclear complex coordinated with pyrazole (L1), 1-(hydroxymethyl)pyrazole) (L2) and oxalate (Ox) ligands has been unexpectedly obtained.
A facile, selective, high recovery system for precious metals based on complexation between melamine and cyanuric acid
Authors: Nagai D. , Kuribayashi T. , Tanaka H. , Morinaga H. , Uehara H. , Yamanobe T.
Published: March 2015

We developed a facile, selective, high recovery system for precious metals based on complexation between melamine and cyanuric acid (denoted as MC) through hydrogen bonding.
Mechanochromism and aggregation induced emission in benzothiazole substituted tetraphenylethylenes: a structure function correlation
Authors: Jadhav Thaksen , Dhokale Bhausaheb , Mobin Shaikh M. , Misra Rajneesh
Published: March 2015

The mechanochromic and aggregation induced emission (AIE) properties of benzothiazole (BT) substituted tetraphenylethylene (TPE)3a–3cwere found to be dependent on the linkage between BT and TPE.
Ligand-directed dibromophenyl benzoate chemistry for rapid and selective acylation of intracellular natural proteins
Authors: Takaoka Yousuke , Nishikawa Yuki , Hashimoto Yuki , Sasaki Kenta , Hamachi Itaru
Published: March 2015

A rapid and selective protein labeling method, LDBB chemistry is a useful tool for natural protein imaging in living cells.
Mechanism of anomalously increased oil displacement with aqueous viscoelastic polymer solutions
Authors: Clarke Andrew , Howe Andrew M. , Mitchell Jonathan , Staniland John , Hawkes Laurence , Leeper Katherine
Published: March 2015

Flows of viscoelastic polymer solutions in porous media exhibit elastic turbulence that destabilises and displaces trapped oil.
Poly(phenyleneethynylene) nanoparticles: preparation, living cell imaging and potential application as drug carriers
Authors: Chen Tong , Xu Wanfu , Huang Zehai , Peng Hongmei , Ke Zhiyong , Lu Xinwei , Yan Yichen , Liu Ruiyuan
Published: March 2015

Novel PPE nanoparticles self-assembled from amphiphilic poly(phenyleneethynylenes) would be a promising drug delivery system for therapeutic delivery and/or bioimaging.
γ radiation induced self-assembly of fluorescent molecules into nanofibers: a stimuli-responsive sensing
Authors: Han Ji-Min , Wu Na , Wang Brian , Wang Chen , Xu Miao , Yang Xiaomei , Yang Haori , Zang Ling
Published: March 2015

γ radiation causes self-assembly of sensor molecules into a nanofibril structure, enabling stimuli-responsive sensing based on fluorescence and photoconductivity modulation.
A unified model to determine the energy partitioning between target and plasma in nanosecond laser ablation of silicon
Authors: Galasso G. , Kaltenbacher M. , Tomaselli A. , Scarpa D.
Published: March 2015

In semiconductor industry, pulsed nanosecond lasers are widely applied for the separation of silicon wafers. Here, the high intensities employed activate a cascade of complex multi-physical and multi-phase mechanisms, which finally result in the formation of a laser induced plasma, shielding the target from the incoming laser beam. Such induced plasma plume, by preventing the laser to effectively reach the target, reduces the overall efficiency and controllability of the ablation process. Modelling can be a useful tool in the optimization of industrial laser applications, allowing a deeper understanding of the way the laser energy distributes between target and induced plasma. Nevertheless, the highly multi-physical character of laser ablation poses serious challenges on the implementation of the various mechanisms underlying the process within a common modelling framework. A novel strategy is here proposed in order to simulate in a simplified, yet physically consistent way, a typical industrial application as laser ablation of silicon wafers. Reasonable agreement with experimental findings is obtained. Three fundamental mechanisms have been identified as the main factors influencing the accuracy of the numerical predictions: the transition from evaporative to volumetric mass removal occurring at critical temperature, the collisional and radiative processes underlying the initial plasma formation stage and the increased impact of the liquid ejection mechanism when a sub-millimeter laser footprint is used.
Dynamic domain wall chirality rectification by rotating magnetic fields
Authors: Bisig Andre , Mawass Mohamad-Assaad , Stärk Martin , Moutafis Christoforos , Rhensius Jan , Heidler Jakoba , Gliga Sebastian , Weigand Markus , Tyliszczak Tolek , Van Waeyenberge Bartel , Stoll Hermann , Schütz Gisela , Kläui Mathias
Published: March 2015

We report on the observation of magnetic vortex domain wall chirality reversal in ferromagnetic rings that is controlled by the sense of rotation of a magnetic field. We use time-resolved X-ray microscopy to dynamically image the chirality-switching process and perform micromagnetic simulations to deduce the switching details from time-resolved snapshots. We find experimentally that the switching occurs within less than 4 ns and is observed in all samples with ring widths ranging from 0.5 μm to 2 μm, ring diameters between 2 μm and 5 μm, and a thickness of 30 nm, where a vortex domain wall is present in the magnetic onion state of the ring. From the magnetic contrast in the time-resolved images, we can identify effects of thermal activation, which plays a role for the switching process. Moreover, we find that the process is highly reproducible so that the domain wall chirality can be set with high fidelity.
An in situ sample environment reaction cell for spatially resolved x-ray absorption spectroscopy studies of powders and small structured reactors
Authors: Zhang Chu , Gustafson Johan , Merte Lindsay R. , Evertsson Jonas , Norén Katarina , Carlson Stefan , Svensson Håkan , Carlsson Per-Anders
Published: March 2015

An easy-to-use sample environment reaction cell for X-ray based in situ studies of powders and small structured samples, e.g., powder, pellet, and monolith catalysts, is described. The design of the cell allows for flexible use of appropriate X-ray transparent windows, shielding the sample from ambient conditions, such that incident X-ray energies as low as 3 keV can be used. Thus, in situ X-ray absorption spectroscopy (XAS) measurements in either transmission or fluorescence mode are facilitated. Total gas flows up to about 500 mln/min can be fed while the sample temperature is accurately controlled (at least) in the range of 25–500 °C. The gas feed is composed by a versatile gas-mixing system and the effluent gas flow composition is monitored with mass spectrometry (MS). These systems are described briefly. Results from simultaneous XAS/MS measurements during oxidation of carbon monoxide over a 4% Pt/Al2O3 powder catalyst are used to illustrate the system performance in terms of transmission XAS. Also, 2.2% Pd/Al2O3 and 2% Ag − Al2O3 powder catalysts have been used to demonstrate X-ray absorption near-edge structure (XANES) spectroscopy in fluorescence mode. Further, a 2% Pt/Al2O3 monolith catalyst was used ex situ for transmission XANES. The reaction cell opens for facile studies of structure-function relationships for model as well as realistic catalysts both in the form of powders, small pellets, and coated or extruded monoliths at near realistic conditions. The applicability of the cell for X-ray diffraction measurements is discussed.
Research Update: Electrical monitoring of cysts using organic electrochemical transistors
Authors: Huerta M. , Rivnay J. , Ramuz M. , Hama A. , Owens R. M.
Published: March 2015

Organotypic three-dimensional (3D) cell culture models have the potential to act as surrogate tissues in vitro, both for basic research and for drug discovery/toxicology. 3D cultures maintain not only 3D architecture but also cell-cell and cell extracellular matrix interactions, particularly when grown in cysts or spheroids. Characterization of cell cultures grown in 3D formats, however, provides a significant challenge for cell biologists due to the incompatibility of these structures with commonly found optical or electronic monitoring systems. Electronic impedance spectroscopy is a cell culture monitoring technique with great potential; however, it has not been possible to integrate 3D cultures with commercially available systems to date. Cyst-like 3D cultures are particularly challenging due to their small size and difficulty in manipulation. Herein, we demonstrate isolation of cyst-like 3D cultures by capillarity and subsequent integration with the organic electrochemical transistor for monitoring the integrity of these structures. We show not only that this versatile device can be adapted to the cyst format for measuring resistance and, therefore, the quality of the cysts, but also can be used for quantitative monitoring of the effect of toxic compounds on cells in a 3D format. The ability to quantitatively predict effects of drugs on 3D cultures in vitro has large future potential for the fields of drug discovery and toxicology.
Quantum and wave dynamical chaos in superconducting microwave billiards
Authors: Dietz B. , Richter A.
Published: March 2015

Experiments with superconducting microwave cavities have been performed in our laboratory for more than two decades. The purpose of the present article is to recapitulate some of the highlights achieved. We briefly review (i) results obtained with flat, cylindrical microwave resonators, so-called microwave billiards, concerning the universal fluctuation properties of the eigenvalues of classically chaotic systems with no, a threefold and a broken symmetry; (ii) summarize our findings concerning the wave-dynamical chaos in three-dimensional microwave cavities; (iii) present a new approach for the understanding of the phenomenon of dynamical tunneling which was developed on the basis of experiments that were performed recently with unprecedented precision, and finally, (iv) give an insight into an ongoing project, where we investigate universal properties of (artificial) graphene with superconducting microwave photonic crystals that are enclosed in a microwave resonator, i.e., so-called Dirac billiards.
Graphene-like conjugated π bond system in Pb1−xSnxSe
Authors: Shu G. J. , Liou S. C. , Karna S. , Sankar R. , Hayashi M. , Chu M.-W. , Chou F. C.
Published: March 2015

Following the identification of the π bond in graphene, in this work, a π bond constructed through side-to-side overlap of half-filled 6pz orbitals was observed in a non-carbon crystal of Pb1–xSnxSe (x ∼ 0.34) (PSS), a prototype topological crystalline insulator and thermoelectric material with a high figure-of-merit. PSS compounds with a rock-salt type cubic crystal structure were found to consist of σ bond connected covalent chains of Pb(Sn)-Se with an additional π bond that is shared as a conjugated system among the four nearest neighbor Pb pairs in square symmetry within all {001} monoatomic layers per cubic unit cell. The π bond formed with half-filled 6pz orbitals between Pb atoms is consistent with the calculated results from quantum chemistry. The presence of π bonds was identified and verified with electron energy-loss spectroscopy through plasmonic excitations and electron density mapping via an inverse Fourier transform of X-ray diffraction.
Improving the dielectric properties of an electrowetting-on-dielectric microfluidic device with a low-pressure chemical vapor deposited Si3N4 dielectric layer
Authors: Shen Hsien-Hua , Chung Lung-Yuan , Yao Da-Jeng
Published: March 2015

Dielectric breakdown is a common problem in a digital microfluidic system, which limits its application in chemical or biomedical applications. We propose a new fabrication of an electrowetting-on-dielectric (EWOD) device using Si3N4 deposited by low-pressure chemical vapor deposition (LPCVD) as a dielectric layer. This material exhibits a greater relative permittivity, purity, uniformity, and biocompatibility than polymeric films. These properties also increase the breakdown voltage of a dielectric layer and increase the stability of an EWOD system when applied in biomedical research. Medium droplets with mouse embryos were manipulated in this manner. The electrical properties of the Si3N4 dielectric layer—breakdown voltage, refractive index, relative permittivity, and variation of contact angle with input voltage—were investigated and compared with a traditional Si3N4 dielectric layer deposited as a plasma-enhanced chemical vapor deposition to confirm the potential of LPCVD Si3N4 applied as the dielectric layer of an EWOD digital microfluidic system.
Non-descanned multifocal multiphoton microscopy with a multianode photomultiplier tube
Authors: Cha Jae Won , Yew Elijah Y. S. , Kim Daekeun , Subramanian Jaichandar , Nedivi Elly , So Peter T. C.
Published: March 2015

Multifocal multiphoton microscopy (MMM) improves imaging speed over a point scanning approach by parallelizing the excitation process. Early versions of MMM relied on imaging detectors to record emission signals from multiple foci simultaneously. For many turbid biological specimens, the scattering of emission photons results in blurred images and degrades the signal-to-noise ratio (SNR). We have recently demonstrated that a multianode photomultiplier tube (MAPMT) placed in a descanned configuration can effectively collect scattered emission photons from each focus into their corresponding anodes significantly improving image SNR for highly scattering specimens. Unfortunately, a descanned MMM has a longer detection path resulting in substantial emission photon loss. Optical design constraints in a descanned geometry further results in significant optical aberrations especially for large field-of-view (FOV), high NA objectives. Here, we introduce a non-descanned MMM based on MAPMT that substantially overcomes most of these drawbacks. We show that we improve signal efficiency up to fourfold with limited image SNR degradation due to scattered emission photons. The excitation foci can also be spaced wider to cover the full FOV of the objective with minimal aberrations. The performance of this system is demonstrated by imaging interneuron morphological structures deep in the brains of living mice.
Plasmon modes of metallic nanowires including quantum nonlocal effects
Authors: Moradi Afshin
Published: March 2015

The properties of electrostatic surface and bulk plasmon modes of cylindrical metallic nanowires are investigated, using the quantum hydrodynamic theory of plasmon excitation which allows an analytical study of quantum tunneling effects through the Bohm potential term. New dispersion relations are obtained for each type of mode and their differences with previous treatments based on the standard hydrodynamic model are analyzed in detail. Numerical results show by considering the quantum effects, as the value of wave number increases, the surface modes are slightly red-shifted first and then blue-shifted while the bulk modes are blue-shifted.
Temperature dependent properties and poling effect of K4CuNb8O23 modified (Na0.5K0.5)NbO3 lead free piezoceramics
Authors: Chen Qiang , Chen Yu , Peng Zhihang , Wu Jiagang , Liu Hong , Xiao Dingquan , Yu Ping , Zhu Jiliang , Zhu Jianguo
Published: March 2015

Lead free piezoelectric ceramics (Na0.5K0.5)NbO3 modified by 4% mol. K4CuNb8O23 (abbreviated NKN:4KCN hereinafter) contain moderate piezoelectric constant d33 ∼ 100 pC N−1 and large mechanical quality factor Qm > 1000, showing possible replacement of the lead-based ones (Chen et al., J Appl. Phys. 102, 104109 (2007)). In terms of practical use, however, the temperature stability of NKN:4KCN is not clear to date. We made a systematic investigation on the properties versus temperature of NKN:4KCN to evaluate whether it can be practically used. In the range from room temperature (RT ∼ 25 °C) to 100 °C, the ferroelectricity of poled NKN:4KCN material is nearly temperature independent, remanent polarization Pr is about 27.6 ±1 μC cm−2. When the as-studied NKN:4KCN ceramics were thermal depolarized in temperature range from RT to 450 °C, piezoelectric constant d33 changed little, retaining about 99 pC N−1, 77 ± 3 pC N−1, from RT to 150 °C, 200 °C to 350 °C, respectively. The poled NKN:4KCN material showed higher orthorhombic to tetragonal phase transition temperature (TO−T ∼ 200 °C) compared to unpoled sample (TO−T ∼ 194 °C). Moreover, this kind of lead free material displayed negative temperature coefficient of frequency (TCF) and positive TCF in orthorhombic and tetragonal phase state, respectively. The TCF was about −360 ppm K−1 in the range from RT to 125 °C, close to some lead-based commercial ones. The significance of this work lies in evaluating whether such a material can be practically used or not. We believe such a material might be the most promising candidate for replacing lead-based ones in some areas in the future.
Can Tauc plot extrapolation be used for direct-band-gap semiconductor nanocrystals?
Authors: Feng Y. , Lin S. , Huang S. , Shrestha S. , Conibeer G.
Published: March 2015

Despite that Tauc plot extrapolation has been widely adopted for extracting bandgap energies of semiconductors, there is a lack of theoretical support for applying it to nanocrystals. In this paper, direct-allowed optical transitions in semiconductor nanocrystals have been formulated based on a purely theoretical approach. This result reveals a size-dependant transition of the power factor used in Tauc plot, increasing from one half used in the 3D bulk case to one in the 0D case. This size-dependant intermediate value of power factor allows a better extrapolation of measured absorption data. Being a material characterization technique, the generalized Tauc extrapolation gives a more reasonable and accurate acquisition of the intrinsic bandgap, while the unjustified purpose of extrapolating any elevated bandgap caused by quantum confinement is shown to be incorrect.
Stabilization of Rayleigh-Taylor instability in a non-Newtonian incompressible complex plasma
Authors: Garai S. , Banerjee D. , Janaki M. S. , Chakrabarti N.
Published: March 2015

The stabilization of Rayleigh-Taylor (RT) instability is investigated in a non-Newtonian unmagnetized dusty plasma with an experimentally verified model of shear flow rate dependent viscosity. It has been found that non-Newtonian property has also a significant role in stabilization of RT instability along with velocity shear stabilization in the short wavelength regime. The effect of the non-Newtonian parameters is more profound in the higher velocity shear rate regime. A detailed study is reported on the role of non-Newtonian effect on RT instability with conventional dust fluid equations using standard numerical eigenvalue analysis.
Hysteresis of the resonance frequency of magnetostrictive bending cantilevers
Authors: Löffler Michael , Kremer Ramona , Sutor Alexander , Lerch Reinhard
Published: March 2015

Magnetostrictive bending cantilevers are applicable for wirelessly measuring physical quantities such as pressure and strain. Exploiting the ΔE-effect, the resonance frequency of the cantilevers is shifted because of a change in the magnetic biasing field. The biasing field, in turn, depends on the applied pressure or strain, respectively. With a view to the application as a reliable sensor, maximum sensitivity but minimum hysteresis in the biasing field/resonance frequency dependence is preferred. In this contribution, monomorph bending cantilevers fabricated using magnetostrictive Fe49Co49V2 and Metglas 2605SA1 are investigated regarding their applicability for future sensors. For this purpose, the biasing field-dependent polarization of the magnetostrictive materials and bending of the cantilevers are determined. Furthermore, a setup to magnetically bias the cantilevers and determine the bending resonance frequency is presented. Here, the resonance frequency is identified by measuring the impulse response employing a laser Doppler vibrometer. The measurement results reveal that cantilevers made of Fe49Co49V2 possess a distinct hysteretic behaviour at low magnetic biasing field magnitudes. This is ascribed to the polarization and bending hysteresis. Cantilevers fabricated using Metglas 2605SA1 feature a lower resonance frequency shift compared to cantilevers with Fe49Co49V2, which would result in a lower sensitivity of the sensor. However, their resonance frequency hysteresis is almost negligible.
Terahertz wave electro-optic measurements with optical spectral filtering
Authors: Ilyakov I. E. , Kitaeva G. Kh. , Shishkin B. V. , Akhmedzhanov R. A.
Published: March 2015

We propose electro-optic detection techniques based on variations of the laser pulse spectrum induced during pulse co-propagation with terahertz wave radiation in a nonlinear crystal. Quantitative comparison with two other detection methods is made. Substantial improvement of the sensitivity compared to the standard electro-optic detection technique (at high frequencies) and to the previously shown technique based on laser pulse energy changes is demonstrated in experiment.
Efficient enhancement of hydrogen production by Ag/Cu2O/ZnO tandem triple-junction photoelectrochemical cell
Authors: Liu Ying , Ren Feng , Shen Shaohua , Fu Yanming , Chen Chao , Liu Chang , Xing Zhuo , Liu Dan , Xiao Xiangheng , Wu Wei , Zheng Xudong , Liu Yichao , Jiang Changzhong
Published: March 2015

Highly efficient semiconductor photoelectrodes for solar hydrogen production through photocatalytic water splitting are a promising and challenge solution to solve the energy problems. In this work, Ag/Cu2O/ZnO tandem triple-junction photoelectrode was designed and prepared. An increase of 11 times of photocurrent is achieved in the Ag/Cu2O/ZnO photoelectrode comparing to that of the Cu2O film. The high performance of the Ag/Cu2O/ZnO film is due to the optimized design of the tandem triple-junction structure, where the localized surface Plasmon resonance of Ag and the hetero-junctions efficiently absorb solar energy, produce, and separate electron-hole pairs in the photocathode.
Phase transitions and thermotropic phase boundaries in MnO2-doped (K0.5Na0.5)NbO3-0.05LiNbO3 single crystals: Raman scattering evidence at elevated temperatures
Authors: Xu L. P. , Jiang K. , Zhang J. Z. , Xu G. S. , Hu Z. G. , Chu J. H.
Published: March 2015

Raman scattering of (K0.5Na0.5)NbO3-0.05LiNbO3-yMnO2 (y = 0% and 1.0%) single crystals have been reported in the temperature range from 300 to 800 K. The spectra exhibit a competition between a soft mode and a relaxation mode upon heating across the diverse transitions. The progressive change in the conflicting displacive mechanism (soft mode) and order-disorder (relaxation mode) can explain the origin of the successive orthorhombic-tetragonal-cubic phase transitions. Moreover, the polymorphic phase transition between orthorhombic and tetragonal structures can be confirmed through the observation of thermotropic phase boundaries for MnO2-doped (K0.5Na0.5)NbO3-0.05LiNbO3 single crystals.
Ion energies in high power impulse magnetron sputtering with and without localized ionization zones
Authors: Yang Yuchen , Tanaka Koichi , Liu Jason , Anders André
Published: March 2015

High speed imaging of high power impulse magnetron sputtering discharges has revealed that ionization is localized in moving ionization zones but localization disappears at high currents for high yield targets. This offers an opportunity to study the effect ionization zones have on ion energies. We measure that ions have generally higher energies when ionization zones are present, supporting the concept that these zones are associated with moving potential humps. We propose that the disappearance of ionization zones is caused by an increased supply of atoms from the target which cools electrons and reduces depletion of atoms to be ionized.
Very low Schottky barrier height at carbon nanotube and silicon carbide interface
Authors: Inaba Masafumi , Suzuki Kazuma , Shibuya Megumi , Lee Chih-Yu , Masuda Yoshiho , Tomatsu Naoya , Norimatsu Wataru , Hiraiwa Atsushi , Kusunoki Michiko , Kawarada Hiroshi
Published: March 2015

Electrical contacts to silicon carbide with low contact resistivity and high current durability are crucial for future SiC power devices, especially miniaturized vertical-type devices. A carbon nanotube (CNT) forest formed by silicon carbide (SiC) decomposition is a densely packed forest, and is ideal for use as a heat-dissipative ohmic contact in SiC power transistors. The contact resistivity and Schottky barrier height in a Ti/CNT/SiC system with various SiC dopant concentrations were evaluated in this study. Contact resistivity was evaluated in relation to contact area. The Schottky barrier height was calculated from the contact resistivity. As a result, the Ti/CNT/SiC contact resistivity at a dopant concentration of 3 × 1018 cm−3 was estimated to be ∼1.3 × 10−4 Ω cm2 and the Schottky barrier height of the CNT/SiC contact was in the range of 0.40–0.45 eV. The resistivity is relatively low for SiC contacts, showing that CNTs have the potential to be a good ohmic contact material for SiC power electronic devices.
Barrier height inhomogeneity in electrical transport characteristics of InGaN/GaN heterostructure interfaces
Authors: Roul Basanta , Mukundan Shruti , Chandan Greeshma , Mohan Lokesh , Krupanidhi S. B.
Published: March 2015

We have grown InGaN/GaN heterostructures using plasma-assisted molecular beam epitaxy and studied the temperature dependent electrical transport characteristics. The barrier height (φb) and the ideally factor (η) estimated using thermionic emission model were found to be temperature dependent. The conventional Richardson plot of ln(Js/T2) versus 1/kT showed two temperature regions (region-I: 400–500 K and region-II: 200–350 K) and it provides Richardson constants (A∗) which are much lower than the theoretical value of GaN. The observed variation in the barrier height and the presence of two temperature regions were attributed to spatial barrier inhomogeneities at the heterojunction interface and was explained by assuming a double Gaussian distribution of barrier heights with mean barrier height values 1.61 and 1.21 eV with standard deviation (σs2) of 0.044 and 0.022 V, respectively. The modified Richardson plot of ln(Js/T2) − (q2σs2/2k2T2) versus 1/kT for two temperature regions gave mean barrier height values as 1.61 eV and 1.22 eV with Richardson constants (A∗) values 25.5 Acm−2K−2 and 43.9 Acm−2K−2, respectively, which are very close to the theoretical value. The observed barrier height inhomogeneities were interpreted on the basis of the existence of a double Gaussian distribution of barrier heights at the interface.
Enhancing the performance of blue GaN-based light emitting diodes with double electron blocking layers
Authors: Guo Yao , Liang Meng , Fu Jiajia , Liu Zhiqiang , Yi Xiaoyan , Wang Junxi , Wang Guohong , Li Jinmin
Published: March 2015

In this work, novel double Electron Blocking Layers for InGaN/GaN multiple quantum wells light-emitting diodes were proposed to mitigate the efficiency droop at high current density. The band diagram and carriers distributions were investigated numerically. The results indicate that due to a newly formed holes stack in the p-GaN near the active region, the hole injection has been improved and an uniform carriers distribution can be achieved. As a result, in our new structure with double Electron Blocking Layers, the efficiency droop has been reduced to 15.5 % in comparison with 57.3 % for the LED with AlGaN EBL at the current density of 100 A/cm2.
Generating and moving Dirac points in a two-dimensional deformed honeycomb lattice arrayed by coupled semiconductor quantum dots
Authors: Peng Juan , Chen PeiJian , Duan Yifeng , Peng Yan
Published: March 2015

Analysis of the electronic properties of a two-dimensional (2D) deformed honeycomb structure arrayed by semiconductor quantum dots (QDs) is conducted theoretically by using tight-binding method in the present paper. Through the compressive or tensile deformation of the honeycomb lattice, the variation of energy spectrum has been explored. We show that, the massless Dirac fermions are generated in this adjustable system and the positions of the Dirac cones as well as slope of the linear dispersions could be manipulated. Furthermore, a clear linear correspondence between the distance of movement d (the distance from the Dirac points to the Brillouin zone corners) and the tunable bond angle α of the lattice are found in this artificial planar QD structure. These results provide the theoretical basis for manipulating Dirac fermions and should be very helpful for the fabrication and application of high-mobility semiconductor QD devices.
Associated particle technique in single-sided geometry for detection of explosives
Authors: Roy Tushar , Kashyap Yogesh , Shukla Mayank , Agrawal Ashish , Bajpai Shefali , Patel Tarun , Sinha Amar
Published: March 2015

Associated particle technique (APT) for detection of explosives is well established but has been implemented mostly for fixed portal systems. In certain situations, a portable system is required where the suspect object cannot be moved from site. This paper discusses the development of a portable APT system in single-sided geometry which can be transported to site and requires only one-sided access to the object. The system comprised D-T neutron source and bismuth germanate (BGO) detectors fixed on a portable module. Different aspects of the system have been discussed such as background contribution, time selection, and elemental signatures. The system was used to detect benign samples and explosive simulants under laboratory condition. The elemental ratios obtained by analyzing the gamma spectra show good match with the theoretical ratios.
A solid dielectric gated graphene nanosensor in electrolyte solutions
Authors: Zhu Yibo , Wang Cheng , Petrone Nicholas , Yu Jaeeun , Nuckolls Colin , Hone James , Lin Qiao
Published: March 2015

This letter presents a graphene field effect transistor (GFET) nanosensor that, with a solid gate provided by a high-κ dielectric, allows analyte detection in liquid media at low gate voltages. The gate is embedded within the sensor and thus is isolated from a sample solution, offering a high level of integration and miniaturization and eliminating errors caused by the liquid disturbance, desirable for both in vitro and in vivo applications. We demonstrate that the GFET nanosensor can be used to measure pH changes in a range of 5.3–9.3. Based on the experimental observations and quantitative analysis, the charging of an electrical double layer capacitor is found to be the major mechanism of pH sensing.
In the Family Way: Bringing a Mother-Daughter (Matrilineal) Perspective to Retail Innovation and Consumer Culture
Authors: Davies Andrea , Fitchett James
Published: March 2015

Here we apply the multilevel narrative approach of critical oral history to develop intergenerational narratives that show how social change in consumer culture is enacted through family interrelations. The research uses intergenerational storytelling to describe memories of women as mothers and daughters in families. Places and practices around provisioning, budgeting, cooking, childcare, and domestic labour provide the setting in which the dialectics of family and gender are transformed through evolving family signatures. Families develop enduring myths that function as a means of making sense of consumption. The oral histories show how family signatures proliferate, how they are shaped by retail innovation, and how they become structured into everyday practices and family norms. This further demonstrates that family is important to understand the relationship between individuals and consumer culture.