bluuebunny/crossref_metadata_2025 huggingface dataset:
Antisense oligonucleotide-mediated exon skipping as a strategy to reduce proteolytic cleavage of ataxin-3
Authors: Toonen Lodewijk J. A. , Schmidt Iris , Luijsterburg Martijn S. , van Attikum Haico , van Roon-Mom Willeke M. C.
Published: October 2016

Spinocerebellar ataxia type-3 (SCA3) is a neurodegenerative disorder caused by a polyglutamine repeat expansion in the ataxin-3 protein. Cleavage of mutant ataxin-3 by proteolytic enzymes yields ataxin-3 fragments containing the polyglutamine stretch. These shorter ataxin-3 fragments are thought to be involved in SCA3 pathogenesis due to their increased cellular toxicity and their involvement in formation of the characteristic neuronal aggregates. As a strategy to prevent formation of toxic cleavage fragments, we investigated an antisense oligonucleotide-mediated modification of the ataxin-3 pre-mRNA through exon skipping of exon 8 and 9, resulting in the removal of a central 88 amino acid region of the ataxin-3 protein. This removed protein region contains several predicted cleavage sites and two ubiquitin-interacting motifs. In contrast to unmodified mutant ataxin-3, the internally truncated ataxin-3 protein did not give rise to potentially toxic cleavage fragments when incubated with caspases. In vitro experiments did not show cellular toxicity of the modified ataxin-3 protein. However, the modified protein was incapable of binding poly-ubiquitin chains, which may interfere with its normal deubiquitinating function. Low exon skipping efficiencies combined with reduction in important ataxin-3 protein functions suggest that skipping of exon 8 and 9 is not a viable therapeutic option for SCA3.
Multistate Redox Switching and Near-Infrared Electrochromism Based on a Star-Shaped Triruthenium Complex with a Triarylamine Core
Authors: Tang Jian-Hong , He Yan-Qin , Shao Jiang-Yang , Gong Zhong-Liang , Zhong Yu-Wu
Published: October 2016

A star-shaped cyclometalated triruthenium complex 2(PF6)n (n = 3 and 4) with a triarylamine core was synthesized, which functions as a molecular switch with five well-separated redox states in both solution and film states. The single-crystal X-ray structure of 2(PF6)3 is presented. This complex displays four consecutive one-electron redox waves at +0.082, +0.31, +0.74, and +1.07 V vs Ag/AgCl. In each redox state, it shows significantly different NIR absorptions with λmax of 1590 nm for 24+, 1400 nm for 25+, 1060 nm for 26+, and 740 nm for 27+, respectively. Complex 24+ shows a single-line EPR signal at g = 2.060, while other redox states are all EPR inactive. The spin density distributions and NIR absorptions in different redox states were rationalized by DFT and TDDFT calculations. A vinyl-substituted triruthenium analogous 3(PF6)4 was prepared, which was successfully polymerized on ITO glass electrode surfaces by reductive electropolymerization. The obtained poly-3n+/ITO film was characterized by FTIR, AFM, and SEM analysis. It shows four well-defined redox couples and reversible multistate NIR electrochromism. In particular, a contrast ratio (ΔT%) up to 63% was achieved at the optic telecommunication wavelength (1550 nm).
High pressure die casting of Fe-based metallic glass
Authors: Ramasamy Parthiban , Szabo Attila , Borzel Stefan , Eckert Jürgen , Stoica Mihai , Bárdos András
Published: October 2016

Soft ferromagnetic Fe-based bulk metallic glass key-shaped specimens with a maximum and minimum width of 25.4 and 5 mm, respectively, were successfully produced using a high pressure die casting (HPDC) method, The influence of die material, alloy temperature and flow rate on the microstructure, thermal stability and soft ferromagnetic properties has been studied. The results suggest that a steel die in which the molten metal flows at low rate and high temperature can be used to produce completely glassy samples. This can be attributed to the laminar filling of the mold and to a lower heat transfer coefficient, which avoids the skin effect in the steel mold. In addition, magnetic measurements reveal that the amorphous structure of the material is maintained throughout the key-shaped samples. Although it is difficult to control the flow and cooling rate of the molten metal in the corners of the key due to different cross sections, this can be overcome by proper tool geometry. The present results confirm that HPDC is a suitable method for the casting of Fe-based bulk glassy alloys even with complex geometries for a broad range of applications.
The wake-promoting drug modafinil stimulates specific hypothalamic circuits to promote adaptive stress responses in an animal model of PTSD
Authors: Cohen S , Ifergane G , Vainer E , Matar M A , Kaplan Z , Zohar J , Mathé A A , Cohen H
Published: October 2016

Pharmacotherapeutic intervention during traumatic memory consolidation has been suggested to alleviate or even prevent the development of posttraumatic stress disorder (PTSD). We recently reported that, in a controlled, prospective animal model, depriving rats of sleep following stress exposure prevents the development of a PTSD-like phenotype. Here, we report that administering the wake-promoting drug modafinil to rats in the aftermath of a stressogenic experience has a similar prophylactic effect, as it significantly reduces the prevalence of PTSD-like phenotype. Moreover, we show that the therapeutic value of modafinil appears to stem from its ability to stimulate a specific circuit within the hypothalamus, which ties together the neuropeptide Y, the orexin system and the HPA axis, to promote adaptive stress responses. The study not only confirms the value of sleep prevention and identifies the mechanism of action of a potential prophylactic treatment after traumatic exposure, but also contributes to understanding mechanisms underlying the shift towards adaptive behavioral response.
The Alkaline Comet Assay in Prognostic Tests for Male Infertility and Assisted Reproductive Technology Outcomes
Authors: Lewis Sheena E. M. , Agbaje Ishola M.
Published: October 2016

In this review the relationship between actual sperm DNA damage as determined by the alkaline Comet assay and potential DNA damage as measured by DNA adduct testing will also be examined and the potential of routine clinical practices such as cryopreservation and prolonged incubation to induce further DNA damage investigated. The usefulness of sperm DNA tests as prognostic markers and in particular, the opportunities and challenges provided by DNA testing in male-fertility determination will be discussed.
Electrochemical determination of mesalazine by using graphene oxide coated with a molecularly imprinted sol–gel
Authors: Kim Songjin , Wang Ning , Li Yijun , He Xiwen
Published: October 2016

Graphene oxide coated with a molecularly imprinted sol–gel for mesalazine determination.
A target-initiated DNA network caged on magnetic particles for amplified chemiluminescence resonance energy transfer imaging of microRNA and targeted drug delivery
Authors: Bi Sai , Yue Shuzhen , Song Weiling , Zhang Shusheng
Published: October 2016

DNA networks are constructed on magnetic particles by an initiator, which are functionalized for CRET imaging assay and targeted drug delivery.
Correction: New layered cobalt oxyfluoride, Sr2CoO3F
Authors: Tsujimoto Yoshihiro , Li Jun J. , Yamaura Kazunari , Matsushita Yoshitaka , Katsuya Yoshio , Tanaka Masahiko , Shirako Yuichi , Akaogi Masaki , Takayama-Muromachi Eiji
Published: October 2016

Correction for ‘New layered cobalt oxyfluoride, Sr2CoO3F’ by Yoshihiro Tsujimoto et al., Chem. Commun., 2011, 47, 3263–3265.
Magnetic anisotropy of a CoII single ion magnet with distorted trigonal prismatic coordination: theory and experiment
Authors: Peng Yan , Bodenstein Tilmann , Fink Karin , Mereacre Valeriu , Anson Christopher E. , Powell Annie K.
Published: October 2016

The single-ion magnetic properties of a trigonal-prismatic Co(ii) complex (left) are explored experimentally as well as analysed with respect to the coordination geometry by quantum chemical ab initio methods.
Photoexcitation and relaxation kinetics of molecular systems in solution: towards a complete in silico model
Authors: Aschi Massimiliano , Barone Vincenzo , Carlotti Benedetta , Daidone Isabella , Elisei Fausto , Amadei Andrea
Published: October 2016

A theoretical–computational method is proposed for modelling the complete kinetics – from photo-excitation to relaxation – of a chromophore in solution.
Anion-directed supramolecular chemistry modulating the magnetic properties of nanoscopic Mn coordination clusters: from polynuclear high-spin complexes to SMMs
Authors: Zhang Lei , Chimamkpam Theresa , Onet Camelia I. , Zhu Nianyong , Clérac Rodolphe , Schmitt Wolfgang
Published: October 2016

We report a supramolecular approach that demonstrates how chloride ions can be applied to influence the structures and magnetic properties of homologous Mn coordination clusters.
Iridium(iii) hydrido complexes for the catalytic dehydrogenation of hydrazine borane
Authors: Han D. , Joksch M. , Klahn M. , Spannenberg A. , Drexler H.-J. , Baumann W. , Jiao H. , Knitsch R. , Hansen M. R. , Eckert H. , Beweries T.
Published: October 2016

A series of POCOP iridium hydride complexes with differently substituted aryl backbones catalyse the selective release of one equivalent of hydrogen from hydrazine borane.
Interactions between 2,4-bis-pteridine-1,5-benzodiazepine and group 12 dihalides: synthesis, spectral and XRD structural studies and theoretical calculations
Authors: Illán-Cabeza Nuria A. , Jiménez-Pulido Sonia B. , Hueso-Ureña Francisco , Peña-Ruiz Tomás , Quirós-Olozábal Miguel , Moreno-Carretero Miguel N.
Published: October 2016

Coordination may strongly affect the stereochemistry of bis-lumazine-1,5-benzodiazepines.
Correction: Post-functionalized iridium–Zr-MOF as a promising recyclable catalyst for the hydrogenation of aromatics
Authors: Rasero-Almansa Antonia M. , Corma Avelino , Iglesias Marta , Sánchez Félix
Published: October 2016

Correction for ‘Post-functionalized iridium–Zr-MOF as a promising recyclable catalyst for the hydrogenation of aromatics’ by Antonia M. Rasero-Almansa, et al., Green Chem., 2014, 16, 3522–3527.
Design of systems based on 4-armed star-shaped polyacids for indomethacin delivery
Authors: Neugebauer Dorota , Odrobińska Justyna , Bielas Rafał , Mielańczyk Anna
Published: October 2016

The pentaerythritol based star-shaped polyacids as micellar nanocarriers with adjustable characteristics for drug delivery have been investigated.
Identification of the binding roles of terminal and internal glycan epitopes using enzymatically synthesized N-glycans containing tandem epitopes
Authors: Wu Zhigang , Liu Yunpeng , Ma Cheng , Li Lei , Bai Jing , Byrd-Leotis Lauren , Lasanajak Yi , Guo Yuxi , Wen Liuqing , Zhu He , Song Jing , Li Yanhong , Steinhauer David A. , Smith David F. , Zhao Baohua , Chen Xi , Guan Wanyi , Wang Peng George
Published: October 2016

Roles of internal epitopes and modification of terminal epitopes in the glycan-binding events have been studied.
An MEDT study of the carbenoid-type [3 + 2] cycloaddition reactions of nitrile ylides with electron-deficient chiral oxazolidinones
Authors: Domingo Luis R. , Ríos-Gutiérrez Mar , Pérez Patricia
Published: October 2016

A combination of the bonding evolution theory and non-covalent interactions analyses of TSs makes it possible to characterise both the carbenoid-type 32CA reaction between a NY and a chiral oxazolidinone, and the diastereoselectivity experimentally observed.
Insertion behavior of imidazolium and pyrrolidinium based ionic liquids into α and β-cyclodextrins: mechanism and factors leading to host–guest inclusion complexes
Authors: Roy Aditi , Saha Subhadeep , Datta Biswajit , Roy Mahendra Nath
Published: October 2016

The encapsulation of [BMIm]Cl and [BMP]Cl within α and β-cyclodextrin in both the solid state and aqueous solution with 1 : 1 supramolecular assembly.
New route to 1,4-oxazepane and 1,4-diazepane derivatives: synthesis from N-propargylamines
Authors: Vessally Esmail , Hosseinian Akram , Edjlali Ladan , Bekhradnia Ahmadreza , Esrafili Mehdi D.
Published: October 2016

N-Propargylamines are one of the most useful and versatile building blocks in organic synthesis that are successfully transformed into many significant N-heterocycles.
Nanoindentation and wear behavior of thermally stable biocompatible polysulfone–alumina nanocomposites
Authors: Llorente Amaia , Serrano Berna , Baselga Juan , Gedler Gabriel , Ozisik Rahmi
Published: October 2016

The functionalization of alumina nanoparticles leads to better dispersion, improving the mechanical and wear resistance of nanocomposites.
An extremely efficient and green method for the acylation of secondary alcohols, phenols and naphthols with a deep eutectic solvent as the catalyst
Authors: Nguyen Hai Truong , Tran Phuong Hoang
Published: October 2016

An efficient and green method was developed for the acylation of secondary alcohols, phenols and naphthols using deep eutectic solvent [CholineCl][ZnCl2]3 as a catalyst at room temperature under solvent-free conditions.
Correction: Simultaneous and combined detection of multiple tumor markers for cancer screening in human serum by an upgraded photonic crystal-encoded suspension array
Authors: Zheng Shiya , Yang Zixue , Chen Yanping , Wu Dan , Zhou Shoubing , Li Lulu , Jin Xiaoxiao , Zhang Xiu , Liu Zhen , Wang Cailian
Published: October 2016

Correction for ‘Simultaneous and combined detection of multiple tumor markers for cancer screening in human serum by an upgraded photonic crystal-encoded suspension array’ by Shiya Zheng et al., RSC Adv., 2016, 6, 92267–92275.
400–450 MHz power amplifier with high‐order harmonic suppression for multi‐protocol transceiver
Authors: Weng Zhaoyang , Jiang Hanjun , Dong Jingjing , Li Fule , Wang Zhihua
Published: October 2016

A combinational biasing technique is presented for a 400–450 MHz power amplifier (PA). By combining two class AB amplifiers with different conduction angles and optimising the design parameters as well, the 5th and 6th harmonics are greatly suppressed in the PA's output. The designed PA is fabricated in 65 nm CMOS technology. Measurement results show that with the presented technique the 5th and 6th harmonic suppressions can be improved by 13 and 17 dB, respectively, compared with a PA with a fixed conduction angle. The presented PA technique can find its important use in multi‐protocol transceivers.
CW operation of high‐power blue laser diodes with polished facets on semi‐polar GaN substrates
Authors: Pourhashemi A. , Farrell R.M. , Cohen D.A. , Becerra D.L. , DenBaars S.P. , Nakamura S.
Published: October 2016

Continuous wave (CW) operation of high‐power blue laser diodes (LDs) with polished facets on semi‐polar (202̅1̅) gallium nitride (GaN) substrates is demonstrated. Ridge waveguide LDs were fabricated using indium GaN waveguiding layers and GaN cladding layers. At a lasing wavelength of 452 nm, the peak two‐facet CW output power from an LD with uncoated facets was 1.71 W at a current of 3 A, corresponding to an optical power density of 32.04 MW/cm2 on each facet. The dependence of output power on current did not change with repeated CW measurements, indicating that the polished facets did not degrade under high‐power CW operation. These results show that polished facets are a viable alternative to cleaved or etched facets for high‐power CW semi‐polar LDs.
80 GBd 6‐bit DAC in InP DHBT for arbitrary waveform generator
Authors: Arayashiki Y. , Ikeda M. , Amano Y.
Published: October 2016

A high‐speed 6‐bit resolution digital‐to‐analogue converter (DAC) for generating four‐level pulse amplitude modulation (PAM4) signals with high waveform quality is designed and fabricated using InP double‐heterojunction bipolar transistor (DHBT) technology. The DAC outputs a clean PAM4 signal at 80 GBd and a sawtooth signal at 80 GS/s.
Analysis of voltage fluctuation impact on induction motors by an innovative equivalent circuit considering the speed changes
Authors: Ghaseminezhad Morteza , Doroudi Aref , Hosseinian Seyed Hossein , Jalilian Alireza
Published: October 2016

The most commonly used motor in industries is induction motor. This motor is exposed to various power quality disturbances. A frequent power quality disturbance which has an adverse effect on induction motor is voltage fluctuations. In this study, the behaviour of three‐phase induction motors under voltage fluctuation conditions is studied. By using the theory of dynamic phasor, an innovative equivalent circuit in which the speed fluctuations are taken into account is presented. The currents, efficiency and power factor under voltage fluctuation conditions are evaluated by the proposed equivalent circuit. The variations of these quantities due to different voltage fluctuation characteristics are also investigated. The simulation results are validated by measurements on the laboratory test setup which comprises a 1.1 kW induction motor excited by a programmable power supply unit.
Removing the wall effects using electromagnetic complex coating layer for ultra‐wideband through wall imaging
Authors: Baharian Mohammad , Rajabalipanah Hamid , Fakheri Mohammad H. , Abdolali Ali
Published: October 2016

The wall‐effect compensation is one of the most annoying steps in modern through wall imaging (TWI) problems. Presence of wall not only increases the computational burden due to clutter rejection and complex imaging algorithms, but also blurs the reconstructed image. To mitigate this drawback, different wall‐clutter rejection methods have been subject of numerous researches in recent years. However, these wall‐clutter rejection methods mainly focus on removing the first strong reflection of wall. In this study, a novel wall‐removal method (not only wall‐clutter rejection) based on transformation optics (TO) is addressed. This is the first time that TO has been applied to TWI problem. Using this new method, TWI is cast to a free space imaging problem which is computationally more effective and results in more focused images. Real‐time imaging is also more available in this case. Without loss of generality, a two‐dimensional TWI configuration is assumed to evaluate the provided technique. A single point‐like scatterer hidden behind a wall is used to obtain the imaging system point spread function resulted by the proposed technique. Finally, it is shown that the presented method is valid even for lossy walls. Reconstructed images show satisfactory focusing that highlight the capabilities of presented method.
Low dislocation density InAlN/AlN/GaN heterostructures grown on GaN substrates and the effects on gate leakage characteristics
Authors: Kotani Junji , Yamada Atsushi , Ishiguro Tetsuro , Tomabechi Shuichi , Nakamura Norikazu
Published: October 2016

This paper reports on the electrical characterization of Ni/Au Schottky diodes fabricated on InAlN high-electron-mobility transistor (HEMT) structures grown on low dislocation density free-standing GaN substrates. InAlN HEMT structures were grown on sapphire and GaN substrates by metal-organic vapor phase epitaxy, and the effects of threading dislocation density on the leakage characteristics of Ni/Au Schottky diodes were investigated. Threading dislocation densities were determined to be 1.8 × 104 cm−2 and 1.2 × 109 cm−2 by the cathodoluminescence measurement for the HEMT structures grown on GaN and sapphire substrates, respectively. Leakage characteristics of Ni/Au Schottky diodes were compared between the two samples, and a reduction of the leakage current of about three to four orders of magnitude was observed in the forward bias region. For the high reverse bias region, however, no significant improvement was confirmed. We believe that the leakage current in the low bias region is governed by a dislocation-related Frenkel–Poole emission, and the leakage current in the high reverse bias region originates from field emission due to the large internal electric field in the InAlN barrier layer. Our results demonstrated that the reduction of dislocation density is effective in reducing leakage current in the low bias region. At the same time, it was also revealed that another approach will be needed, for instance, band modulation by impurity doping and insertion of insulating layers beneath the gate electrodes for a substantial reduction of the gate leakage current.
Thermophysical properties and conduction mechanisms in AsxSe1−x chalcogenide glasses ranging from x = 0.2 to 0.5
Authors: Lonergan Jason , Smith Charmayne , McClane Devon , Richardson Kathleen
Published: October 2016

The arsenic (As) to selenium (Se) ratio in AsxSe1-x glasses ranging from x = 0.2 to 0.5 was varied in order to examine the effect of chemical and topological ordering on the glass' thermal transport behavior. The fundamental thermal properties of glass transition temperature (Tg), thermal conductivity (k), and heat capacity (cp) were experimentally measured using differential scanning calorimetry, transient plane source method, and ultrasonic testing. Based on topological constraint theory, inflections in Tg and k were found at the structural coordination number ⟨r⟩ of 2.4, whereas a slight increase in heat capacity (cp) with increasing ⟨r⟩ was observed. A maximum in total thermal conductivity of 0.232 W/m·K was measured for the composition with x = 0.4, which corresponds to the stoichiometric As2Se3. Gas kinetic theory was used to derive an expression for the photon (kp) portion of thermal conductivity, which was calculated by measurements of the glass' absorption coefficient (α) and refractive index (n). Models based on Debye theory were used to derive expressions for specific heat (cv) and the lattice (kl) portion of thermal conductivity. The maximum value for kp was 0.173 W/m·K for the composition with x = 0.2, and a minimum value of 0.144 W/m·K was measured for the composition with x = 0.4. Photonic conduction was found to be the dominant carrier mechanisms in all compositions, comprising 60% to 95% of the measured total thermal conductivity.
Angle dependent antireflection property of TiO2 inspired by cicada wings
Authors: Zada Imran , Zhang Wang , Li Yao , Sun Peng , Cai Nianjin , Gu Jiajun , Liu Qinglei , Su Huilan , Zhang Di
Published: October 2016

Inspired by cicada wings, biomorphic TiO2 with antireflective structures (ARSs) was precisely fabricated using a simple, inexpensive, and highly effective sol-gel process combined with subsequent calcination. It was confirmed that the fabricated biomorphic TiO2 not only effectively inherited the ARS but also exhibited high-performance angle dependent antireflective properties ranging from normal to 45°. Reflectance spectra demonstrated that the reflectivity of the biomorphic TiO2 with ARSs gradually changed from 1.4% to 7.8% with the increasing incidence angle over a large visible wavelength range. This angle dependent antireflective property is attributed to an optimized gradient refractive index between air and TiO2 via ARSs on the surface. Such surfaces with ARSs may have potential application in solar cells.
Synchronization of clocks through 12 km of strongly turbulent air over a city
Authors: Sinclair Laura C. , Swann William C. , Bergeron Hugo , Baumann Esther , Cermak Michael , Coddington Ian , Deschênes Jean-Daniel , Giorgetta Fabrizio R. , Juarez Juan C. , Khader Isaac , Petrillo Keith G. , Souza Katherine T. , Dennis Michael L. , Newbury Nathan R.
Published: October 2016

We demonstrate real-time, femtosecond-level clock synchronization across a low-lying, strongly turbulent, 12-km horizontal air path by optical two-way time transfer. For this long horizontal free-space path, the integrated turbulence extends well into the strong turbulence regime corresponding to multiple scattering with a Rytov variance up to 7 and with the number of signal interruptions exceeding 100 per second. Nevertheless, optical two-way time transfer is used to synchronize a remote clock to a master clock with femtosecond-level agreement and with a relative time deviation dropping as low as a few hundred attoseconds. Synchronization is shown for a remote clock based on either an optical or microwave oscillator and using either tip-tilt or adaptive-optics free-space optical terminals. The performance is unaltered from optical two-way time transfer in weak turbulence across short links. These results confirm that the two-way reciprocity of the free-space time-of-flight is maintained both under strong turbulence and with the use of adaptive optics. The demonstrated robustness of optical two-way time transfer against strong turbulence and its compatibility with adaptive optics is encouraging for future femtosecond clock synchronization over very long distance ground-to-air free-space paths.
A valence state evaluation of a positive electrode material in an Li-ion battery with first-principles K- and L-edge XANES spectral simulations and resonance photoelectron spectroscopy
Authors: Kubobuchi Kei , Mogi Masato , Matsumoto Masashi , Baba Teruhisa , Yogi Chihiro , Sato Chikai , Yamamoto Tomoyuki , Mizoguchi Teruyasu , Imai Hideto
Published: October 2016

X-ray absorption near edge structure (XANES) analysis is an element-specific method for proving electronic state mostly in the field of applied physics, such as battery and catalysis reactions, where the valence change plays an important role. In particular, many results have been reported for the analysis of positive electrode materials of Li-ion batteries, where multiple transition materials contribute to the reactions. However, XANES analysis has been limited to identifying the valence state simply in comparison with reference materials. When the shape of XANES spectra shows complicated changes, we were not able to identify the valence states or estimate the valence quantitatively, resulting in insufficient reaction analysis. To overcome such issues, we propose a valence state evaluation method using K- and L-edge XANES analysis with first-principles simulations. By using this method, we demonstrated that the complicated reaction mechanism of Li(Ni1/3Co1/3Mn1/3)O2 can be successfully analyzed for distinguishing each contribution of Ni, Co, Mn, and O to the redox reactions during charge operation. In addition to the XANES analysis, we applied resonant photoelectron spectroscopy (RPES) and diffraction anomalous fine structure spectroscopy (DAFS) with first-principles calculations to the reaction analysis of Co and Mn, which shows no or very little contribution to the redox. The combination of RPES and first-principles calculations successfully enables us to confirm the contribution of Co at high potential regions by electively observing Co 3d orbitals. Through the DAFS analysis, we deeply analyzed the spectral features of Mn K-edges and concluded that the observed spectral shape change for Mn does not originate from the valence change but from the change in distribution of wave functions around Mn upon Li extraction.
A route to high gain photodetectors through suppressed recombination in disordered films
Authors: Philippa Bronson , White Ron , Pivrikas Almantas
Published: October 2016

Secondary photocurrents offer an alternative mechanism to photomultiplier tubes and avalanche diodes for making high gain photodetectors that are able to operate even at extremely low light conditions. While in the past secondary currents were studied mainly in ordered crystalline semiconductors, disordered systems offer some key advantages such as a potentially lower leakage current and typically longer photocarrier lifetimes due to trapping. In this work, we use numerical simulations to identify the critical device and material parameters required to achieve high photocurrent and gain in steady state. We find that imbalanced mobilities and suppressed, non-Langevin-type charge carrier recombination will produce the highest gain. A low light intensity, strong electric field, and a large single carrier space charge limited current are also beneficial for reaching high gains. These results would be useful for practical photodetector fabrication when aiming to maximize the gain.
Improving the radiation hardness of graphene field effect transistors
Authors: Alexandrou Konstantinos , Masurkar Amrita , Edrees Hassan , Wishart James F. , Hao Yufeng , Petrone Nicholas , Hone James , Kymissis Ioannis
Published: October 2016

Ionizing radiation poses a significant challenge to the operation and reliability of conventional silicon-based devices. Here, we report the effects of gamma radiation on graphene field-effect transistors (GFETs), along with a method to mitigate those effects by developing a radiation-hardened version of our back-gated GFETs. We demonstrate that activated atmospheric oxygen from the gamma ray interaction with air damages the semiconductor device, and damage to the substrate contributes additional threshold voltage instability. Our radiation-hardened devices, which have protection against these two effects, exhibit minimal performance degradation, improved stability, and significantly reduced hysteresis after prolonged gamma radiation exposure. We believe this work provides an insight into graphene's interactions with ionizing radiation that could enable future graphene-based electronic devices to be used for space, military, and other radiation-sensitive applications.
ITER-like antenna capacitors voltage probes: Circuit/electromagnetic calculations and calibrations
Authors: Helou W. , Dumortier P. , Durodié F. , Lombard G. , Nicholls K. ,   JET Contributors
Published: October 2016

The analyses illustrated in this manuscript have been performed in order to provide the required data for the amplitude-and-phase calibration of the D-dot voltage probes used in the ITER-like antenna at the Joint European Torus tokamak. Their equivalent electrical circuit has been extracted and analyzed, and it has been compared to the one of voltage probes installed in simple transmission lines. A radio-frequency calibration technique has been formulated and exact mathematical relations have been derived. This technique mixes in an elegant fashion data extracted from measurements and numerical calculations to retrieve the calibration factors. The latter have been compared to previous calibration data with excellent agreement proving the robustness of the proposed radio-frequency calibration technique. In particular, it has been stressed that it is crucial to take into account environmental parasitic effects. A low-frequency calibration technique has been in addition formulated and analyzed in depth. The equivalence between the radio-frequency and low-frequency techniques has been rigorously demonstrated. The radio-frequency calibration technique is preferable in the case of the ITER-like antenna due to uncertainties on the characteristics of the cables connected at the inputs of the voltage probes. A method to extract the effect of a mismatched data acquisition system has been derived for both calibration techniques. Finally it has been outlined that in the case of the ITER-like antenna voltage probes can be in addition used to monitor the currents at the inputs of the antenna.
Role of convective cell in nonlinear interaction of kinetic Alfvén waves
Authors: Luk O. O. , Lin Z.
Published: October 2016

Gyrokinetic particle simulations show that electrostatic convective cell (CC) can be generated by kinetic Alfvén waves and plays a dominant role in the nonlinear interactions underlying perpendicular spectral cascade. The CC growth rate increases linearly with the field amplitude of the pump waves and has a small but finite threshold, and decreases with the parallel wavevector. The CC growth is proportional to the perpendicular wavevector when there are two pump waves, but proportional to the square of the perpendicular wavevector when there is a single pump wave.
Ultrafast lattice dynamics in lead selenide quantum dot induced by laser excitation
Authors: Wang Xuan , Rahmani Hamidreza , Zhou Jun , Gorfien Matthew , Mendez Plaskus Joshua , Li Dong , Voss Ryan , Nelson Cory A. , Wai Lei Kin , Wolcott Abraham , Zhu Xiaoyang , Li Junjie , Cao Jianming
Published: October 2016

We directly monitored the lattice dynamics in PbSe quantum dots (QD) induced by laser excitation using ultrafast electron diffraction. The energy relaxation between the carriers and the lattice took place within 10 ps, showing no evidence of any significant phonon bottleneck effect. Meanwhile, the lattice dilation exhibited some unusual features that could not be explained by the available mechanisms of photon-induced acoustic vibrations in semiconductors alone. The heat transport between the QDs and the substrate deviates significantly from Fourier's Law, which opens questions about the heat transfer under nonequilibrium conditions in nanoscale materials.
Addressing the problem of uniform converging spherical shock wave in water
Authors: Nitishinskiy M. , Efimov S. , Yanuka D. , Gurovich V. Tz. , Krasik Ya. E.
Published: October 2016

Time-resolved parameters of plasma compressed by a shock wave generated by the underwater electrical explosion of a spherical wire array are presented. The plasma was preliminarily formed inside a capillary placed at the equatorial plane along the axis of the array. Temporal evolution analysis of Hα and C II spectral lines showed that the plasma density increases from its initial value of ∼3 × 1017 cm−3 up to ∼5.5 × 1017 cm−3 within 300 ± 25 ns. These results were found to be in agreement with those of the model that considers the adiabatic compression of the plasma by the converging capillary walls caused by interaction with the incident shock wave with a pressure of ∼3 × 109 Pa at a radius of 1.5 mm. The latter results coincide well with those of the 1D hydrodynamic modeling, which assumes uniformity of the converging shock wave.
Communication: Finite size correction in periodic coupled cluster theory calculations of solids
Authors: Liao Ke , Grüneis Andreas
Published: October 2016

We present a method to correct for finite size errors in coupled cluster theory calculations of solids. The outlined technique shares similarities with electronic structure factor interpolation methods used in quantum Monte Carlo calculations. However, our approach does not require the calculation of density matrices. Furthermore we show that the proposed finite size corrections achieve chemical accuracy in the convergence of second-order Møller-Plesset perturbation and coupled cluster singles and doubles correlation energies per atom for insulating solids with two atomic unit cells using 2 × 2 × 2 and 3 × 3 × 3 k-point meshes only.
Self-consistent double-hybrid density-functional theory using the optimized-effective-potential method
Authors: Śmiga Szymon , Franck Odile , Mussard Bastien , Buksztel Adam , Grabowski Ireneusz , Luppi Eleonora , Toulouse Julien
Published: October 2016

We introduce an orbital-optimized double-hybrid (DH) scheme using the optimized-effective-potential (OEP) method. The orbitals are optimized using a local potential corresponding to the complete exchange-correlation energy expression including the second-order Møller-Plesset correlation contribution. We have implemented a one-parameter version of this OEP-based self-consistent DH scheme using the BLYP density-functional approximation and compared it to the corresponding non-self-consistent DH scheme for calculations on a few closed-shell atoms and molecules. While the OEP-based self-consistency does not provide any improvement for the calculations of ground-state total energies and ionization potentials, it does improve the accuracy of electron affinities and restores the meaning of the LUMO orbital energy as being connected to a neutral excitation energy. Moreover, the OEP-based self-consistent DH scheme provides reasonably accurate exchange-correlation potentials and correlated densities.
Autonomous generation of a thermoacoustic solitary wave in an air-filled tube
Authors: Shimizu Dai , Sugimoto Nobumasa
Published: October 2016

Experiments are performed to demonstrate the autonomous generation of an acoustic solitary wave in an air-filled, looped tube with an array of Helmholtz resonators. The solitary wave is generated spontaneously due to thermoacoustic instability by a pair of stacks installed in the tube and subject to a temperature gradient axially. No external drivers are used to create initial disturbances. Once the solitary wave is generated, it keeps on propagating to circulate along the loop endlessly. The stacks, which are made of ceramics and of many pores of square cross section, are placed in the tube diametrically on exactly the opposite side of the loop, and they are sandwiched by hot and cold (ambient) heat exchangers. When the temperature gradient along both stacks is appropriate, pulses of smooth profiles are generated and propagated in both directions of the tube. From good agreements of not only the pressure profile measured but also the propagation speed with the theory, the pulse is identified as the acoustic solitary wave, and it can be called thermoacoustic solitary wave or thermoacoustic soliton corresponding to the soliton solution of the K-dV equation in one limit.
Numerical simulation of a triode source of intense radial converging electron beam
Authors: Altsybeyev V. , Engelko V. , Ovsyannikov A. , Ovsyannikov D. , Ponomarev V. , Fetzer R. , Mueller G.
Published: October 2016

The results of numerical simulations of a triode source of an intense radial converging electron beam are presented. The role of the initial transverse velocity of electrons, defocusing effect of the controlling grid, the beam self-magnetic field, backscattering of electrons, and ion flow from the target is analyzed. It was found that the ion flow from the target essentially increases the value of the electron current. The influence of the beam self-magnetic field on electron trajectories leads to the fact that there is a critical value of the cathode-grid voltage dividing the mode of the source operation into stable and unstable. The influence of initial transverse electron energies on the beam focusing is essentially higher than the influence of the controlling grid. Backscattering of the beam electrons from the target surface increases the target ion current so that the source operation may become unstable and the distribution of the beam power density on the target becomes nonuniform with a maximum in the center. Electrons passing by the target drift along the source axis. This leads to diminishing the power density at the center of the target and to the exit of peripheral electrons from the source. Conditions for achieving required electron beam parameters (the electron kinetic energy—120 keV, the beam energy density on the target ∼40 J/cm2 on a maximum possible length of the target surface) were determined.
On the Gaudin model associated to Lie algebras of classical types
Authors: Lu Kang , Mukhin E. , Varchenko A.
Published: October 2016

We derive explicit formulas for solutions of the Bethe ansatz equations of the Gaudin model associated to the tensor product of one arbitrary finite-dimensional irreducible module and one vector representation for all simple Lie algebras of classical type. We use this result to show that the Bethe ansatz is complete in any tensor product where all but one factor are vector representations and the evaluation parameters are generic.
Gaussian polarizable-ion tight binding
Authors: Boleininger Max , Guilbert Anne AY , Horsfield Andrew P.
Published: October 2016

To interpret ultrafast dynamics experiments on large molecules, computer simulation is required due to the complex response to the laser field. We present a method capable of efficiently computing the static electronic response of large systems to external electric fields. This is achieved by extending the density-functional tight binding method to include larger basis sets and by multipole expansion of the charge density into electrostatically interacting Gaussian distributions. Polarizabilities for a range of hydrocarbon molecules are computed for a multipole expansion up to quadrupole order, giving excellent agreement with experimental values, with average errors similar to those from density functional theory, but at a small fraction of the cost. We apply the model in conjunction with the polarizable-point-dipoles model to estimate the internal fields in amorphous poly(3-hexylthiophene-2,5-diyl).
Lattice model for water-solute mixtures
Authors: Furlan A. P. , Almarza N. G. , Barbosa M. C.
Published: October 2016

A lattice model for the study of mixtures of associating liquids is proposed. Solvent and solute are modeled by adapting the associating lattice gas (ALG) model. The nature of interaction of solute/solvent is controlled by tuning the energy interactions between the patches of ALG model. We have studied three set of parameters, resulting in, hydrophilic, inert, and hydrophobic interactions. Extensive Monte Carlo simulations were carried out, and the behavior of pure components and the excess properties of the mixtures have been studied. The pure components, water (solvent) and solute, have quite similar phase diagrams, presenting gas, low density liquid, and high density liquid phases. In the case of solute, the regions of coexistence are substantially reduced when compared with both the water and the standard ALG models. A numerical procedure has been developed in order to attain series of results at constant pressure from simulations of the lattice gas model in the grand canonical ensemble. The excess properties of the mixtures, volume and enthalpy as the function of the solute fraction, have been studied for different interaction parameters of the model. Our model is able to reproduce qualitatively well the excess volume and enthalpy for different aqueous solutions. For the hydrophilic case, we show that the model is able to reproduce the excess volume and enthalpy of mixtures of small alcohols and amines. The inert case reproduces the behavior of large alcohols such as propanol, butanol, and pentanol. For the last case (hydrophobic), the excess properties reproduce the behavior of ionic liquids in aqueous solution.
Integrated closed-loop cavity of a tunable laser
Authors: Ren M. , Cai H. , Gu Y. D. , Chin L. K. , Radhakrishnan K. , Ser W. , Sun H. D. , Liang Q. X. , Kwong D.-L. , Liu A. Q.
Published: October 2016

In this paper, a closed-loop cavity of a tunable laser integrated onto a silicon chip is demonstrated. The closed-loop cavity consists of a semiconductor optical amplifier chip, two separated micro-ring resonators, and a U-shaped waveguide sub-loop, enabling dominating lasing in the counterclockwise direction. The lasing wavelength is tuned by varying the effective refractive index of the thermal ring-resonators. It has achieved wide tuning range (55.4 nm), high spectral purity (50-dB side mode suppression ratio), ∼1-mW output power, and 36-dB counter-propagation power suppression ratio. The integrated tunable laser has high potential in applications such as optical network, optical sensing, and integrated optoelectronic systems.
Calculated electronic, transport, and related properties of zinc blende boron arsenide (zb-BAs)
Authors: Nwigboji Ifeanyi H. , Malozovsky Yuriy , Franklin Lashounda , Bagayoko Diola
Published: October 2016

We present the results from ab-initio, self-consistent density functional theory (DFT) calculations of electronic, transport, and bulk properties of zinc blende boron arsenide. We utilized the local density approximation potential of Ceperley and Alder, as parameterized by Vosko and his group, the linear combination of Gaussian orbitals formalism, and the Bagayoko, Zhao, and Williams (BZW) method, as enhanced by Ekuma and Franklin (BZW-EF), in carrying out our completely self-consistent calculations. With this method, the results of our calculations have the full, physical content of density functional theory (DFT). Our results include electronic energy bands, densities of states, effective masses, and the bulk modulus. Our calculated, indirect band gap of 1.48 eV, from Γ to a conduction band minimum close to X, for the room temperature lattice constant of 4.777 Å, is in an excellent agreement with the experimental value of 1.46 ± 0.02 eV. We thoroughly explain the reasons for the excellent agreement between our findings and corresponding, experimental ones. This work provides a confirmation of the capability of DFT to describe accurately properties of materials, if the computations adhere strictly to the conditions of validity of DFT, as done by the BZW-EF method.
Crystal growth in Se70Te30 thin films followed by SEM and in situ XRD
Authors: Martinková Simona , Barták Jaroslav , Málek Jiri , Segawa Hiroyo
Published: October 2016

The isothermal crystal growth kinetics in Se70Te30 thin films was investigated using the microscopy and in situ X-ray diffraction (XRD) measurements. Plate-like crystals grew linearly with time which is the sign of liquid-crystal interface kinetics. In the studied temperature range, from 68 °C to 88 °C, crystal growth rates exhibit simple exponential behavior with an activation energy of crystal growth EG = 168 ± 12 kJ mol−1. The growth data obtained from the microscopy measurements were combined with viscosity data, melting parameters and the appropriate crystal growth model was assessed. The relation between the kinetic coefficient of crystal growth and viscosity (u∝η-ξ) is described in detail, and a correction of the standard growth model is suggested. The crystal growth data obtained from the in situ XRD measurements were described using the Johnson-Mehl-Avrami nucleation-growth model with the Avrami exponent m = 2.2 ± 0.2. The activation energy of the overall crystallization process EA was estimated and its value is 171 ± 11 kJ mol−1.
Electronic properties of Si-doped AlxGa1−xN with aluminum mole fractions above 80%
Authors: Mehnke Frank , Trinh Xuan Thang , Pingel Harald , Wernicke Tim , Janzén Erik , Son Nguyen Tien , Kneissl Michael
Published: October 2016

The dependence of the activation energy as well as the energetic levels of the neutral charge state and the DX center of the Si donor in AlxGa1−xN:Si samples on aluminum content and SiH4/III ratio were investigated by electron paramagnetic resonance (EPR) measurements, Van-der-Pauw resistivity measurements, and Hall-effect measurements. It was found by EPR measurements that the energy distance of the neutral charge state of the Si donor from the conduction band increases with increasing aluminum content from 61 meV for x = 0.82 to 106 meV for x = 0.89. Additionally, the formation of a DX center below the neutral charge state which is deepening from 6 meV for x = 0.82 to 58 meV for x = 0.89 is observed. This results in a linearly increasing activation energy with increasing aluminum content from 67 meV for x = 0.82 to 164 meV for x = 0.89. This is consistent with the activation energies as determined by Hall-effect measurements showing a linear increase from 24 meV for x = 0.85 to 211 meV for x = 0.96, as well as the activation energies as determined by Van-der-Pauw resistivity measurements. By varying the SiH4/III ratio we observed a formation of a minimum resistivity in accordance with the room temperature charge carrier density. However, no clear dependence of the activation energy was observed. EPR measurements of samples with a high SiH4/III ratio hint to an increased incorporation probability of a deep secondary donor species which might explain the increase in resistivity.