bluuebunny/crossref_metadata_2025 huggingface dataset:
Ionic liquid-mediated synthesis of meso-scale porous lanthanum-transition-metal perovskites with high CO oxidation performance
Authors: Lu Hanfeng , Zhang Pengfei , Qiao Zhen-An , Zhang Jinshui , Zhu Huiyuan , Chen Jihua , Chen Yinfei , Dai Sheng
Published: February 2015

Mesoporous lanthanum-transition-metal perovskites with high CO oxidation performance are synthesized by facilitation through ionic liquids.
Using Li+ as the electrochemical messenger to fabricate an aqueous rechargeable Zn–Cu battery
Authors: Zhang Hanping , Yang Tao , Wu Xin , Zhou Yisen , Yang Chao , Zhu Tian , Dong Rulin
Published: February 2015

Li+ ions driven by the electrochemical potential in an aqueous Zn–Cu rechargeable battery could be called the electrochemical messenger.
In situ production of visible light absorbing Ti-based nanoparticles in solution and in a photopolymerizable cationic matrix
Authors: Lalevée J. , Poupart R. , Bourgon J. , Fouassier J.-P. , Versace D.-L.
Published: February 2015

The synthesis of visible-light absorbing Ti NPs from photoinitiating systems based on titanium(iv) propoxide derivatives/iodonium salt under light activation.
Correction: A new, cheap, and productive FeP anode material for sodium-ion batteries
Authors: Li Wei-Jie , Chou Shu-Lei , Wang Jia-Zhao , Liu Hua-Kun , Dou Shi-Xue
Published: February 2015

Correction for ‘A new, cheap, and productive FeP anode material for sodium-ion batteries’ by Wei-Jie Li et al., Chem. Commun., 2015, DOI: 10.1039/c4cc09604e.
The first example of Tb3-containing metallopolymer-type hybrid materials with efficient and high color-purity green luminescence
Authors: Zhang Zhao , Feng Heini , Liu Lin , Yu Chao , Lü Xingqiang , Zhu Xunjin , Wong Wai-Kwok , Jones Richard A. , Pan Mei , Su Chengyong
Published: February 2015

In the obtained Tb3+-based efficient (Φoverall = 76–83%) and high color-purity green luminescent 3@PMMA from doping and metallopolymer-type Poly(NBE-3), grafting endows a higher-concentration self-quenching.
A remarkable enhancement in Am3+/Eu3+selectivity by an ionic liquid based solvent containing bis-1,2,4-triazinyl pyridine derivatives: DFT validation of experimental results
Authors: Bhattacharyya Arunasis , Ansari Seraj A. , Gadly Trilochan , Ghosh Sunil K. , Mohapatra Manoj , Mohapatra P. K.
Published: February 2015

Different complexation behaviour in RTIL medium resulted in an enhancement in selectivity up to a few thousands with MeBTP.
Influence of Bi3+-doping on the magnetic and Mössbauer properties of spinel cobalt ferrite
Authors: Gore Shyam K. , Mane Rajaram S. , Naushad Mu. , Jadhav Santosh S. , Zate Manohar K. , Alothman Z. A. , Hui Biz K. N.
Published: February 2015

Bi3+-doping improves the saturation magnetization, coercivity and the remanence magnetization, which can be applied for magnetic recording and memory devices, of CoFe2O4 ferrite.
Synthesis, characterization and investigation of the photophysical and photochemical properties of highly soluble novel metal-free, zinc(ii), and indium(iii) phthalocyanines substituted with 2,3,6-trimethylphenoxy moieties
Authors: Gürel Ekrem , Pişkin Mehmet , Altun Selçuk , Odabaş Zafer , Durmuş Mahmut
Published: February 2015

The synthesis, characterization and photophysicochemical properties of 2,3,6-trimethylphenoxy substituted metal-free, zinc(ii), and indium(iii)acetate phthalocyanines were described.
Hierarchical zigzag Na1.25V3O8 nanowires with topotactically encoded superior performance for sodium-ion battery cathodes
Authors: Dong Yifan , Li Shuo , Zhao Kangning , Han Chunhua , Chen Wei , Wang Bingliang , Wang Lei , Xu Boan , Wei Qiulong , Zhang Lei , Xu Xu , Mai Liqiang
Published: February 2015

Topotactically synthesized hierarchical zigzag Na1.25V3O8 nanowires with an optimized morphology and a crystal structure exhibit excellent performances as Na-ion battery cathodes.
Kinetics of aggregation and growth processes of PEG-stabilised mono- and multivalent gold nanoparticles in highly concentrated halide solutions
Authors: Stein Benjamin , Zopes David , Schmudde Madlen , Schneider Ralf , Mohsen Ahmed , Goroncy Christian , Mathur Sanjay , Graf Christina
Published: February 2015

5–6 nm gold nanoparticles were prepared by hydrolytic decomposition of [NMe4][Au(CF3)2] and functionalizedin situwith mono- and multivalent thiolated PEG ligands. Time-dependent changes of the nanoparticles were monitored in aqueous NaCl, NaBr, and NaI solutions by UV-Vis spectroscopy, TEM, and HRTEM. The purely sterically protected particles are stable in ≤1 M NaCl and NaBr solutions, regardless of the valence of the ligands. At higher concentrations (≥2 M), the monovalent stabilized particles show minor reaction limited colloidal aggregation. In NaBr but not in NaCl solutions a minor Ostwald ripening also occurs. The divalent stabilized particles remain colloidally stable in both halide solutions, even if the temperature is raised or the concentration is increased above 2 M. In ≤1 M aqueous NaI solutions the particles remain stable. Above, the monovalent stabilized particles undergo an oxidative reaction, resulting in a time-dependent shift and broadening of the absorbance spectrum. Finally, this process slows down while the width of the spectra slightly narrows. The kinetics of this process can be described by a two-step sigmoidal process, comprising a slow induction period where active species are formed, followed by a fast growth and aggregation process. The increasing concentration of fused structures from the aggregates during this process results in a narrowing of the size distributions. The divalent stabilized particles show only some minor broadening and a slight shift of the absorbance spectra in ≤3 M NaI solutions. These observations confirm the excellent stability of the multivalent stabilized particles from this chloride-free particle synthesis.
Copper intoxication inhibits aerobic nucleotide synthesis in Streptococcus pneumoniae
Authors: Johnson Michael D. L. , Kehl-Fie Thomas E. , Rosch Jason W.
Published: February 2015

Graphical model of copper export and toxicity in S. pneumoniae.
Surface charge effects in protein adsorption on nanodiamonds
Authors: Aramesh M. , Shimoni O. , Ostrikov K. , Prawer S. , Cervenka J.
Published: February 2015

An electrostatic model is developed to qualitatively explain the protein adsorption based on charge-induced pH modifications near the charged nanoparticles/surfaces.
Real-time monitoring of enzyme-free strand displacement cascades by colorimetric assays
Authors: Duan Ruixue , Wang Boya , Hong Fan , Zhang Tianchi , Jia Yongmei , Huang Jiayu , Hakeem Abdul , Liu Nannan , Lou Xiaoding , Xia Fan
Published: February 2015

We report a simple colorimetric method using gold nanoparticles as signal generators for the real-time detection of the product of the strand displacement cascade.
Palladium-catalyzed regio-selective oxidative C–H bond acylation of azoxybenzenes with alcohols
Authors: Hou Lekai , Chen Xiangxiang , Li Shuang , Cai Suxian , Zhao Yanxia , Sun Meng , Yang Xiao-Juan
Published: February 2015

A novel catalytic system for theortho-acetyl functionalization of azoxybenzenesviaa regio-selective directing-group-assisted strategy was developed.
Highly thermally stable hydrogels derived from monolayered two-dimensional supramolecular polymers
Authors: Zhou Tian-You , Qi Qiao-Yan , Zhao Qiao-Ling , Fu Jie , Liu Yi , Ma Zhi , Zhao Xin
Published: February 2015

Hydrogels have been constructed from monolayered two-dimensional (2D) supramolecular polymers in water. The as-prepared hydrogels exhibited extremely high thermal stabilities, which demonstrates how the 2D structure can impact the bulk properties of soft materials.
In situ polymerization of aniline on carbon quantum dots: a new platform for ultrasensitive detection of glucose and hydrogen peroxide
Authors: Zhang Yanmei , Yang Xinjian , Gao Zhiqiang
Published: February 2015

A simple and highly sensitive carbon quantum dot based sensing platform for glucose and hydrogen peroxide.
BiOBr–BiOI microsphere assembled with atom-thick ultrathin nanosheets and its high photocatalytic activity
Authors: Guo Xue-Jing , Zhen Mengmeng , Liu Huajie , Liu Lu
Published: February 2015

BiOBr–BiOI composite microspheres assembled with atom-thick ultrathin nanosheets have been synthesized via a simple solvothermal route with the surfactant polyvinylpyrrolidone.
Plasmodium falciparum subtilisin-like protease 1: discovery of potent difluorostatone-based inhibitors
Authors: Giovani Simone , Penzo Maria , Butini Stefania , Brindisi Margherita , Gemma Sandra , Novellino Ettore , Campiani Giuseppe , Blackman Michael J. , Brogi Simone
Published: February 2015

We here describe the development of potent inhibitors of the malaria parasite enzyme subtilisin-like protease 1 (PfSUB1).
Transforming organic molecular films into carbon films as solid lubricants
Authors: Liang Hongyu , Bu Yongfeng , Zhou Yan , Wang Yongfu , Zhang Junyan
Published: February 2015

Transforming electrophoresis-deposited organic film into low-wear carbon film with controllable thickness as superior solid lubricant.
Improving students’ chemical literacy levels on thermochemical and thermodynamics concepts through a context-based approach
Authors: Cigdemoglu Ceyhan , Geban Omer
Published: February 2015

The aim of this study was to delve into the effect of context-based approach (CBA) over traditional instruction (TI) on students’ chemical literacy level related to thermochemical and thermodynamics concepts. Four eleventh-grade classes with 118 students in total taught by two teachers from a public high school in 2012 fall semester were enrolled in this particular study. The treatments were randomly assigned to the already formed classes; experimental groups were treated as CBA, the control groups as TI. Each teacher had one experimental and one control group. Open-ended contextual item sets were developed to assess students’ chemical literacy level in thermochemical and thermodynamics concepts. The test was administered to both groups as a post-test at the end of the implementation. Students’ responses to item sets were analyzed based on the rubric prepared as the answer key. Analysis of Covariance (ANCOVA) was used for interpreting the data. The results reveal that CBA is superior to TI on improving students’ chemical literacy levels, implying that CBA, as a discussion platform for concepts through real-life experiences, has a significant role in increasing students’ chemical literacy levels in abstract and difficult concepts regardless of the gender difference.
Processing Speed Measures as Clinical Markers for Children With Language Impairment
Authors: Park Jisook , Miller Carol A. , Mainela-Arnold Elina
Published: February 2015

Purpose

This study investigated the relative utility of linguistic and nonlinguistic processing speed tasks as predictors of language impairment (LI) in children across 2 time points.

Method

Linguistic and nonlinguistic reaction time data, obtained from 131 children (89 children with typical development [TD] and 42 children with LI; 74 boys and 57 girls) were analyzed in the 3rd and 8th grades. Receiver operating characteristic curve analyses and likelihood ratios were used to compare the diagnostic usefulness of each task. A binary logistic regression was used to test whether combined measures enhanced diagnostic accuracy.

Results

In 3rd grade, a linguistic task, grammaticality judgment, provided the best discrimination between LI and TD groups. In 8th grade, a combination of linguistic and nonlinguistic tasks, rhyme judgment and simple response time, provided the best discrimination between groups.

Conclusions

Processing speed tasks were moderately predictive of LI status at both time points. Better LR+ than LR– values suggested that slow processing speed was more predictive of the presence than the absence of LI. A nonlinguistic processing measure contributed to the prediction of LI only at 8th grade, consistent with the view that nonlinguistic and linguistic processing speeds follow different developmental trajectories.
Examination of the Locus of Positional Effects on Children's Production of Plural
–s
: Considerations From Local and Global Speech Planning
Authors: Theodore Rachel M. , Demuth Katherine , Shattuck-Hufnagel Stefanie
Published: February 2015

Purpose

Prosodic and articulatory factors influence children's production of inflectional morphemes. For example, plural
–s
is produced more reliably in utterance-final compared to utterance-medial position (i.e., the positional effect), which has been attributed to the increased planning time in utterance-final position. In previous investigations of plural
–s
, utterance-medial plurals were followed by a stop consonant (e.g.,
dog

s

bark
), inducing high articulatory complexity. We examined whether the positional effect would be observed if the utterance-medial context were simplified to a following vowel.

Method

An elicited imitation task was used to collect productions of plural nouns from 2-year-old children. Nouns were elicited utterance-medially and utterance-finally, with the medial plural followed by either a stressed or an unstressed vowel. Acoustic analysis was used to identify evidence of morpheme production.

Results

The positional effect was absent when the morpheme was followed by a vowel (e.g.,
dog

s

eat
). However, it returned when the vowel-initial word contained 2 syllables (e.g.,
dog

s

arrive
), suggesting that the increased processing load in the latter condition negated the facilitative effect of the easy articulatory context.

Conclusions

Children's productions of grammatical morphemes reflect a rich interaction between emerging levels of linguistic competence, raising considerations for diagnosis and rehabilitation of language disorders.
AlN film SAW resonator integrated with metal structure
Authors: Shu Lin , Jiang Jianying , Peng Bin , Wang Yu , Liu Xingzhao
Published: February 2015

A novel surface acoustic wave (SAW) resonator integrated on a metal substrate is presented. The devices were fabricated on the aluminium nitride (AlN) thin films deposited by mid‐frequency magnetron sputtering on polished TC4 titanium alloy substrates. Using a two‐step growth method, AlN film with a full‐width at half‐maximum of 4.1° had been prepared. The AlN film SAW resonator shows a resonance frequency of 129 MHz and an electromechanical coupling coefficient of 0.28%. The measurement results agree well with the simulation results. This integrated SAW resonator can be used as a good strain sensor in metal structure health monitoring.
Broadband superluminescent diode light source at 1330 nm with 180 nm spectral bandwidth
Authors: Kostin Yu. , Chamorovskiy A. , Yakubovich S.D.
Published: February 2015

A broadband light source that is based on a combination of three spectrally matched superluminescent diodes is demonstrated. The mean wavelength of the source is 1330 nm. The 3 dB spectrum width exceeds 180 nm and the 10 dB spectrum width is 220 nm. The spectral flatness is better than 2 dB and the residual spectral modulation is <0.5 dB for the whole spectral bandwidth of the source. The optical power coupled in a single‐mode fibre is 4 mW.
Wideband three‐way out‐of‐phase microstrip power divider
Authors: Zhang Xu Chun , Wang Tong Yang , Xiang Yong Bo , Liang Chang Hong
Published: February 2015

A wideband three‐way out‐of‐phase microstrip power divider based on the wideband phase inverter is presented. The measured return loss is <−10 dB and the isolations are better than −19 dB from 2.5 to 5.37 GHz. The insertion losses are <0.6 dB, and the output amplitude imbalances are <0.9 dB. The phase differences (ang(S41)–ang(S42)) are within 180 ± 6°. The operation bandwidth of the proposed design achieves about 73.4% efficiency.
Directive and high‐efficiency slotted waveguide antenna array for V‐band made by wire electrical discharge machining
Authors: Hotte D. , Siragusa R. , Duroc Y. , Tedjini S.
Published: February 2015

High‐efficiency and directive antennas are nowadays required for wireless communications and applications in the 57–66 GHz ISM band. A slotted waveguide antenna array operating at 58.8 GHz and made in aluminium by wire electrical discharge machining and a milling technique is presented. A −10 dB bandwidth of 3.54 GHz is achieved while the antenna exhibits a measured realised gain of 10.7 dBi at a resonance frequency of 58.8 GHz, with a high total efficiency of 95%. By defining the simulation model under CST according to the accuracy of the manufacturing process, simulation and measurement results are in excellent agreement.
Additional data transmission with rotated QPSK constellation
Authors: Hong Sungwon , Kang Eun Su , Han Dong Seog
Published: February 2015

A quadrature phase‐shift keying (QPSK) modulation scheme is proposed to improve the data rate using the rotated constellation. The additional data is not physically transmitted to improve the spectral efficiency, but it can be detected in the receiver through the rotated phases of constellations. In this Letter, the performance of the proposed transmission scheme is verified by simulation and mathematical analysis with the majority detection rule as the lower bound.
Partial interference alignment for downlink multi‐cell multi‐input–multi‐output networks
Authors: Zhang Yang , Zhou Zheng , Li Bin , Gu Chaozhi , Shu Ruo
Published: February 2015

Interference alignment (IA) is a novel technique to achieve the optimal degree of freedom of wireless communication systems through efficient interference management. In a large size multi‐cell network, IA over a full connected model requires the impractical number of transmit/receive antennas. Moreover, extensive channel state information is delivered over the backhaul between different base‐stations. For realistic scenarios with limited quantity of transceiver antennas, such a full IA scheme may even become infeasible. In this study, by exploiting the heterogeneous path losses, the authors propose a novel partial IA scheme to enhance the throughput of multi‐cell networks, which requires relatively small amounts of antennas and hence can be practically implemented. They first formulate the partial IA problem in terms of a mixed integer bi‐level non‐linear optimal program. Then, they decompose the problem into two sub‐problems to reduce the computation complexity and, furthermore, introduce two algorithms for interference links selection. It is shown that, in a 19 hexagonal wrap‐around‐cell layout, their proposed algorithm outperforms a standard multi‐user multi‐input–multi‐output technique with far less transmit antennas. The present scheme is therefore of great promise to practical applications.
Quadruple‐feed beam‐controlled antenna array for the localisations of ultra‐high‐frequency radio‐frequency identification tags
Authors: Lee Wang‐Sang , Tae Hyun‐Sung , Yu Jong‐Won
Published: February 2015

Item‐level tagging has been required to the retail market with densely placed items as well as the production line. Owing to the multi‐path fading, the blind spots where the tag is non‐responsive can be created. Furthermore, in case of the indoor radio‐frequency identification (RFID) localisation system, additional circuits and localisation algorithms are indispensable for accurate localisation of RFID tags. In this study, in order to solve this problem, the beam‐controlled antenna array with a quadruple beamforming network which generates multiple beams is presented for ultra‐high‐frequency (UHF) RFID systems. The proposed quadruple‐feed antenna array can cover the wide spatial coverage, and the main beam directions of the proposed array can be controlled by selecting the appropriate input port of the quadruple network. The fabricated antenna array with the quadruple‐feed network operates at the 902–928 MHz band and produces scannable multiple beams for UHF RFID localisation system within the wide interrogation zone.
Uniform circular array pattern synthesis using second‐order cone programming
Authors: Dorsey William Mark , Coleman Jeffrey O. , Pickles William R.
Published: February 2015

Here, the authors formulate second‐order cone programs (SOCPs) for synthesising complex weights for far‐field directional (single‐point mainbeam) patterns for narrowband arrays. These formulations, while constructed here with the uniform circular array (UCA) in mind, are actually quite general in that they control the arbitrary‐pol sidelobe level (SLL) and co‐pol signal‐to‐noise ratio loss relative to ideal by minimising either while upper bounding the other. The SLL can be addressed in either an L‐infinity sense or an L1 sense, and elements are assumed characterised by individual embedded complex patterns, modelled or measured, and so need not be identical. Conformal arrays are the obvious application, but we leave that for others and here instead apply the SOCPs to UCAs of directional elements. Design examples assume an antipodal Vivaldi element design with an embedded element pattern obtained through simulation using appropriate unit‐cell boundary conditions. Rotation and translation of that simulated pattern provides embedded element patterns for all elements of the circular array.
Exploiting intrinsic fluctuations to identify model parameters
Authors: Zimmer Christoph , Sahle Sven , Pahle Jürgen
Published: February 2015

Parameterisation of kinetic models plays a central role in computational systems biology. Besides the lack of experimental data of high enough quality, some of the biggest challenges here are identification issues. Model parameters can be structurally non‐identifiable because of functional relationships. Noise in measured data is usually considered to be a nuisance for parameter estimation. However, it turns out that intrinsic fluctuations in particle numbers can make parameters identifiable that were previously non‐identifiable. The authors present a method to identify model parameters that are structurally non‐identifiable in a deterministic framework. The method takes time course recordings of biochemical systems in steady state or transient state as input. Often a functional relationship between parameters presents itself by a one‐dimensional manifold in parameter space containing parameter sets of optimal goodness. Although the system's behaviour cannot be distinguished on this manifold in a deterministic framework it might be distinguishable in a stochastic modelling framework. Their method exploits this by using an objective function that includes a measure for fluctuations in particle numbers. They show on three example models, immigration‐death, gene expression and Epo‐EpoReceptor interaction, that this resolves the non‐identifiability even in the case of measurement noise with known amplitude. The method is applied to partially observed recordings of biochemical systems with measurement noise. It is simple to implement and it is usually very fast to compute. This optimisation can be realised in a classical or Bayesian fashion.
Migrant Women and Social Reproduction under Austerity
Authors: Lonergan Gwyneth
Published: February 2015

Since coming to power in 2010, the UK Coalition government has enacted a series of cuts to public spending, under the auspices of austerity. Underpinning these cuts is a neo-liberal model of citizenship, in which citizens are expected to be autonomous, independent and economically productive, and in which the responsibilities of citizenship outweigh the rights. This model of citizenship is characterised by a paradoxical approach to social reproduction. The Coalition government has taken a significant interest in social reproduction as a means of creating the next generation of ‘good’ neo-liberal citizens; yet, the current austerity measures involve the withdrawal of state support for social reproduction activities. Drawing on participant observation carried out with migrant women's groups in Sheffield and Manchester, as well as interviews with group members, this article demonstrates how the government's paradoxical approach to social reproduction, combined with gendered and racialised discourses of citizenship and ‘Britishness’, have led to policies that place ethnic minority migrant women in an untenable situation. The social reproduction activities of ethnic minority migrant women are the subject of intense government interest, because of the concern that they will be unable to produce ‘good’ neo-liberal citizens. In some cases, this has led to government policies clearly intended to dissuade ‘undesirable’ migrants from having children. In other cases, migrant women are expected to show their commitment to integration, both for themselves and their children, specifically by learning English, even as the government has drastically cut funding for English as a Second or Other Language (ESOL) classes. While seemingly paradoxical, this is in keeping with a racialised neo-liberal model of citizenship under which the ‘responsible’ migrant mother should be able to parent and learn English without government assistance. Nonetheless, these policies are actually self-defeating, as they prevent migrant women from exhibiting the very characteristics of neo-liberal citizenship that they are ostensibly trying to encourage.
Hope with Qualms: A Feminist Analysis of the 2013 Gezi Protests
Authors: Potuoğlu-Cook Öykü
Published: February 2015

In this article, I argue for the distinctness of the 2013 Gezi uprisings from other anti-austerity protests. With a materialist feminist eye on the third-term AKP government's conservative authoritarianism, I explore the causal links among patriarchal, racist biopolitics, heteronormative family values and increasing austerity measures. My broader analytical goal is to demonstrate the centrality of moral politics to uneven, security-based neoliberal regulations across markets, public spaces, and civic expression in and beyond Turkey. Second, I zoom in on the mothers’ rallies and gendered, ethnic acts of mourning to analyse the performative constitution of multiple publics during the protests. What exclusions have the participants produced in the name of inclusion? How can a performance paradigm help us understand the contradictory uses of space among and against the protestors, and more broadly, the relevance of embodied dissent to different visions of social justice? To deepen our intersectional feminist analysis, I suggest taking performances seriously, from human chains to soundscapes of resistance, stillness, and brutality; and from eclectic dance forms to architectural disruptions. Attending to the uprisings’ fault-lines and radical contributions, I also caution against ‘romancing resistance’. Hope with qualms is what remains.
Experimental verification of the Boltzmann relation at the wall in inductively coupled plasmas
Authors: Kim Young-Cheol , Kim June Young , Lee Hyo-Chang , Kim Yu-Sin , Kim Jin-Yong , Cho Sung-Won , Chung Chin-Wook
Published: February 2015

The radial profiles of the electron density at the bottom wall were measured from the center to the edge at argon 3 mTorr with an RF power of 200 W. Since the Boltzmann relation in terms of the fluid picture only describes the behavior of the confined particles, the escaping electrons, which are not confined in plasmas, were not expected to follow the Boltzmann relation. However, unexpected results were observed. The spatial profiles of the density of escaping electrons and the floating potential were well described by the Boltzmann relation with the electron temperature. Moreover, it was concluded that the behavior of the escaping electrons is also described by the generalized Boltzmann relation in terms of the kinetic model.
Ultrathin body GaSb-on-insulator p-channel metal-oxide-semiconductor field-effect transistors on Si fabricated by direct wafer bonding
Authors: Yokoyama Masafumi , Yokoyama Haruki , Takenaka Mitsuru , Takagi Shinichi
Published: February 2015

We have realized ultrathin body GaSb-on-insulator (GaSb-OI) on Si wafers by direct wafer bonding technology using atomic-layer deposition (ALD) Al2O3 and have demonstrated GaSb-OI p-channel metal-oxide-semiconductor field-effect transistors (p-MOSFETs) on Si. A 23-nm-thick GaSb-OI p-MOSFET exhibits the peak effective mobility of ∼76 cm2/V s. We have found that the effective hole mobility of the thin-body GaSb-OI p-MOSFETs decreases with a decrease in the GaSb-OI thickness or with an increase in Al2O3 ALD temperature. The InAs passivation of GaSb-OI MOS interfaces can enhance the peak effective mobility up to 159 cm2/V s for GaSb-OI p-MOSFETs with the 20-nm-thick GaSb layer.
Mechanisms for the inversion of chirality: Global reaction route mapping of stereochemical pathways in a probable chiral extraterrestrial molecule, 2-aminopropionitrile
Authors: Kaur Ramanpreet , Vikas
Published: February 2015

2-Aminopropionitrile (APN), a probable candidate as a chiral astrophysical molecule, is a precursor to amino-acid alanine. Stereochemical pathways in 2-APN are explored using Global Reaction Route Mapping (GRRM) method employing high-level quantum-mechanical computations. Besides predicting the conventional mechanism for chiral inversion that proceeds through an achiral intermediate, a counterintuitive flipping mechanism is revealed for 2-APN through chiral intermediates explored using the GRRM. The feasibility of the proposed stereochemical pathways, in terms of the Gibbs free-energy change, is analyzed at the temperature conditions akin to the interstellar medium. Notably, the stereoinversion in 2-APN is observed to be more feasible than the dissociation of 2-APN and intermediates involved along the stereochemical pathways, and the flipping barrier is observed to be as low as 3.68 kJ/mol along one of the pathways. The pathways proposed for the inversion of chirality in 2-APN may provide significant insight into the extraterrestrial origin of life.
Basis convergence of range-separated density-functional theory
Authors: Franck Odile , Mussard Bastien , Luppi Eleonora , Toulouse Julien
Published: February 2015

Range-separated density-functional theory (DFT) is an alternative approach to Kohn-Sham density-functional theory. The strategy of range-separated density-functional theory consists in separating the Coulomb electron-electron interaction into long-range and short-range components and treating the long-range part by an explicit many-body wave-function method and the short-range part by a density-functional approximation. Among the advantages of using many-body methods for the long-range part of the electron-electron interaction is that they are much less sensitive to the one-electron atomic basis compared to the case of the standard Coulomb interaction. Here, we provide a detailed study of the basis convergence of range-separated density-functional theory. We study the convergence of the partial-wave expansion of the long-range wave function near the electron-electron coalescence. We show that the rate of convergence is exponential with respect to the maximal angular momentum L for the long-range wave function, whereas it is polynomial for the case of the Coulomb interaction. We also study the convergence of the long-range second-order Møller-Plesset correlation energy of four systems (He, Ne, N2, and H2O) with cardinal number X of the Dunning basis sets cc − p(C)V XZ and find that the error in the correlation energy is best fitted by an exponential in X. This leads us to propose a three-point complete-basis-set extrapolation scheme for range-separated density-functional theory based on an exponential formula.
Amino-terminated biphenylthiol self-assembled monolayers as highly reactive molecular templates
Authors: Meyerbroeker N. , Waske P. , Zharnikov M.
Published: February 2015

Self-assembled monolayers (SAMs) with amino tail groups are of interest due to their ability of coupling further compounds. Such groups can be, in particular, created by electron irradiation of nitro- or nitrile-substituted aromatic SAMs, which provide a basis for chemical nanolithography and the fabrication of functionalized nanomembranes. An estimate of reactivity of the created amino groups requires a reference system of homogeneous, amino-terminated aromatic SAMs, which can also be used as a highly reactive molecular template. Here, we describe the synthesis of 4′-aminobiphenyl-4-thiol (ABPT) and SAMs prepared from this precursor on Au(111). The monolayers were characterized by X-ray photoelectron spectroscopy and near edge X-ray absorption fine structure spectroscopy, which revealed that they are well defined, chemically uniform, densely packed, and highly ordered. To examine the influence of electron irradiation on the reactivity of the terminal amino groups, ABPT SAMs were exposed to low energy (50 eV) electrons up to a dose of 40 mC/cm2 and, subsequently, immersed in either trifluoroacetic, pentafluoropropionic, or heptafluorobutyric anhydride. Analysing the amount of the attached anhydride species made it possible to determine the percentage of reactive amino groups as well as the effect of steric hindrance upon the coupling reaction. The above results are compared with those obtained for the well-established nitro-substituted biphenylthiol monolayers.
Electron temperature measurement in Maxwellian non-isothermal beam plasma of an ion thruster
Authors: Zhang Zun , Tang Haibin , Kong Mengdi , Zhang Zhe , Ren Junxue
Published: February 2015

Published electron temperature profiles of the beam plasma from ion thrusters reveal many divergences both in magnitude and radial variation. In order to know exactly the radial distributions of electron temperature and understand the beam plasma characteristics, we applied five different experimental approaches to measure the spatial profiles of electron temperature and compared the agreement and disagreement of the electron temperature profiles obtained from these techniques. Experimental results show that the triple Langmuir probe and adiabatic poly-tropic law methods could provide more accurate space-resolved electron temperature of the beam plasma than other techniques. Radial electron temperature profiles indicate that the electrons in the beam plasma are non-isothermal, which is supported by a radial decrease (∼2 eV) of electron temperature as the plume plasma expands outward. Therefore, the adiabatic “poly-tropic law” is more appropriate than the isothermal “barometric law” to be used in electron temperature calculations. Moreover, the calculation results show that the electron temperature profiles derived from the “poly-tropic law” are in better agreement with the experimental data when the specific heat ratio (γ) lies in the range of 1.2-1.4 instead of 5/3.
Design and analysis of a direct-drive wind power generator with ultra-high torque density
Authors: Jian Linni , Shi Yujun , Wei Jin , Zheng Yanchong
Published: February 2015

In order to get rid of the nuisances caused by mechanical gearboxes, generators with low rated speed, which can be directly connected to wind turbines, are attracting increasing attention. The purpose of this paper is to propose a new direct-drive wind power generator (DWPG), which can offer ultra-high torque density. First, magnetic gear (MG) is integrated to achieve non-contact torque transmission and speed variation. Second, armature windings are engaged to achieve electromechanical energy conversion. Interior permanent magnet (PM) design on the inner rotor is adopted to boost the torque transmission capability of the integrated MG. Nevertheless, due to lack of back iron on the stator, the proposed generator does not exhibit prominent salient feature, which usually exists in traditional interior PM (IPM) machines. This makes it with good controllability and high power factor as the surface-mounted permanent magnet machines. The performance is analyzed using finite element method. Investigation on the magnetic field harmonics demonstrates that the permanent-magnetic torque offered by the MG can work together with the electromagnetic torque offered by the armature windings to balance the driving torque captured by the wind turbine. This allows the proposed generator having the potential to offer even higher torque density than its integrated MG.
Analytic model and frequency characteristics of plasma synthetic jet actuator
Authors: Zong Hao-hua , Wu Yun , Li Ying-hong , Song Hui-min , Zhang Zhi-bo , Jia Min
Published: February 2015

This paper reports a novel analytic model of a plasma synthetic jet actuator (PSJA), considering both the heat transfer effect and the inertia of the throat gas. Both the whole cycle characteristics and the repetitive working process of PSJA can be predicted with this model. The frequency characteristics of a PSJA with 87 mm3 volume and different orifice diameters are investigated based on the analytic model combined with experiments. In the repetitive working mode, the actuator works initially in the transitional stage with 20 cycles and then in the dynamic balanced stage. During the transitional stage, major performance parameters of PSJA experience stepped growth, while during the dynamic balanced stage, these parameters are characterized by periodic variation. With a constant discharge energy of 6.9 mJ, there exists a saturated frequency of 4 kHz/6 kHz for an orifice diameter of 1 mm/1.5 mm, at which the time-averaged total pressure of the pulsed jet reaches a maximum. Between 0.5 mm and 1.5 mm, a larger orifice diameter leads to a higher saturated frequency due to the reduced jet duration time. As the actuation frequency increases, both the time-averaged cavity temperature and the peak jet velocity initially increase and then remain almost unchanged at 1600 K and 280 m/s, respectively. Besides, with increasing frequency, the mechanical energy incorporated in single pulsed jet, the expelled mass per pulse, and the time-averaged density in the cavity, decline in a stair stepping way, which is caused by the intermittent decrease of refresh stage duration in one period.
Neutron resonance spin-echo upgrade at the three-axis spectrometer FLEXX
Authors: Groitl F. , Keller T. , Quintero-Castro D. L. , Habicht K.
Published: February 2015

We describe the upgrade of the neutron resonance spin-echo setup at the cold neutron triple-axis spectrometer FLEXX at the BER II neutron source at the Helmholtz-Zentrum Berlin. The parameters of redesigned key components are discussed, including the radio frequency (RF) spin-flip coils, the magnetic shield, and the zero field coupling coils. The RF-flippers with larger beam windows allow for an improved neutron flux transfer from the source to the sample and further to the analyzer. The larger beam cross sections permit higher coil inclination angles and enable measurements on dispersive excitations with a larger slope of the dispersion. Due to the compact design of the spin-echo units in combination with the increased coil tilt angles, the accessible momentum-range in the Larmor diffraction mode is substantially enlarged. In combination with the redesigned components of the FLEXX spectrometer, including the guide, the S-bender polarizer, the double focusing monochromator, and a Heusler crystal analyzer, the count rate increased by a factor of 15.5, and the neutron beam polarization is enhanced. The improved performance extends the range of feasible experiments, both for inelastic scattering on excitation lifetimes in single crystals, and for high-resolution Larmor diffraction. The experimental characterization of the instrument components demonstrates the reliable performance of the new neutron resonance spin-echo option, now available for the scientific community at FLEXX.
Study on the characteristics of a two gap capillary discharge
Authors: Huang D. , Yang L. J. , Huo P. , Ma J. B. , Ding W. D. , Wang W.
Published: February 2015

The paper presents a new two-gap capillary (TGC) discharge structure. The prominent innovation is the introduction of the middle electrode, which divides the capillary into the trigger gap and the main gap. The discharge circuit of the TGC comprises the trigger circuit and the main circuit. The two circuits are used for the pre-ionization of the trigger gap and providing energy of 450 J for the main gap arc discharging, respectively. When the discharge initiates, the trigger gap is pre-ionized under high voltage pulse produced by trigger circuit, and meanwhile, the weakly ionized plasma is generated. The main circuit then maintains the expansion of the plasma, which is called soft capillary discharge. Afterwards, the main gap is shorted and discharges under a relatively low voltage. With the optimization of the circuit parameter, both the energy deposition ratio in main gap and the degree of plasma ionization are enhanced. The efficiency of the energy deposition is almost twice higher compared with that of the conventional capillary structure. The life performance test indicates that the erosion of the middle electrode and the trigger gap carbonization are the key factors that limit the life performance of the TGC.
Properties of toroidal Alfvén eigenmode in DIII-D plasma
Authors: Wang Zhixuan , Lin Zhihong , Deng Wenjun , Holod Ihor , Heidbrink W. W. , Xiao Y. , Zhang H. , Zhang W. , Van Zeeland M.
Published: February 2015

Linear properties of the toroidal Alfvén eigenmode (TAE) excited by energetic particles (EP) in a DIII-D tokamak experiment have been studied in global gyrokinetic particle simulations treating self-consistently kinetic effects of EP, thermal ions, and electrons. Simulation results of the TAE frequency and mode structure agree very well with the experimental measurements. The non-perturbative EP contribution induces a radial localization of the TAE mode structure, a break-down of mode radial symmetry, as well as a frequency dependence on the toroidal mode number. The simulations further demonstrate the dependence of the growth rate and mode structure on EP pressure gradients. The in-out asymmetry of the mode structure and the experimental identification of the poloidal harmonics have also been clarified.
Angular radiation temperature simulation for time-dependent capsule drive prediction in inertial confinement fusion
Authors: Jing Longfei , Jiang Shaoen , Yang Dong , Li Hang , Zhang Lu , Lin Zhiwei , Li Liling , Kuang Longyu , Huang Yunbao , Ding Yongkun
Published: February 2015

The x-ray drive on a capsule in an inertial confinement fusion setup is crucial for ignition. Unfortunately, a direct measurement has not been possible so far. We propose an angular radiation temperature simulation to predict the time-dependent drive on the capsule. A simple model, based on the view-factor method for the simulation of the radiation temperature, is presented and compared with the experimental data obtained using the OMEGA laser facility and the simulation results acquired with VISRAD code. We found a good agreement between the time-dependent measurements and the simulation results obtained using this model. The validated model was then used to analyze the experimental results from the Shenguang-III prototype laser facility. More specifically, the variations of the peak radiation temperatures at different view angles with the albedo of the hohlraum, the motion of the laser spots, the closure of the laser entrance holes, and the deviation of the laser power were investigated. Furthermore, the time-dependent radiation temperature at different orientations and the drive history on the capsule were calculated. The results indicate that the radiation temperature from “U20W112” (named according to the diagnostic hole ID on the target chamber) can be used to approximately predict the drive temperature on the capsule. In addition, the influence of the capsule on the peak radiation temperature is also presented.
Angular-dependent Raman study of a- and s-plane InN
Authors: Filintoglou K. , Katsikini M. , Arvanitidis J. , Christofilos D. , Lotsari A. , Dimitrakopulos G. P. , Vouroutzis N. , Ajagunna A. O. , Georgakilas A. , Zoumakis N. , Kourouklis G. A. , Ves S.
Published: February 2015

Angular-dependent polarized Raman spectroscopy was utilized to study nonpolar a-plane (11¯20) and semipolar s-plane (101¯1) InN epilayers. The intensity dependence of the Raman peaks assigned to the vibrational modes A1(TO), E1(TO), and E2h on the angle ψ that corresponds to rotation around the growth axis, is very well reproduced by using expressions taking into account the corresponding Raman tensors and the experimental geometry, providing thus a reliable technique towards assessing the sample quality. The s- and a-plane InN epilayers grown on nitridated r-plane sapphire (Al2O3) exhibit good crystalline quality as deduced from the excellent fitting of the experimental angle-dependent peak intensities to the theoretical expressions as well as from the small width of the Raman peaks. On the contrary, in the case of the s-plane epilayer grown on non-nitridated r-plane sapphire, fitting of the angular dependence is much worse and can be modeled only by considering the presence of two structural modifications, rotated so as their c-axes are almost perpendicular to each other. Although the presence of the second variant is verified by transmission electron and atomic force microscopies, angular dependent Raman spectroscopy offers a non-destructive and quick way for its quantification. Rapid thermal annealing of this sample did not affect the angular dependence of the peak intensities. The shift of the E1(TO) and E2h Raman peaks was used for the estimation of the strain state of the samples.
Effects of microstructure and water on the electrical potentials in bone induced by ultrasound irradiation
Authors: Tsuneda H. , Matsukawa S. , Takayanagi S. , Mizuno K. , Yanagitani T. , Matsukawa M.
Published: February 2015

The healing mechanism of bone fractures by low intensity pulse ultrasound is yet to be fully understood. There have been many discussions regarding how the high frequency dynamic stress can stimulate numerous cell types through various pathways. As one possible initial process of this mechanism, we focus on the piezoelectricity of bone and demonstrate that bone can generate electrical potentials by ultrasound irradiation in the MHz range. We have fabricated ultrasonic bone transducers using bovine cortical bone as the piezoelectric device. The ultrasonically induced electrical potentials in the transducers change as a function of time during immersed ultrasonic pulse measurements and become stable when the bone is fully wet. In addition, the magnitude of the induced electrical potentials changes owing to the microstructure in the cortical bone. The potentials of transducers with haversian structure bone are higher than those of plexiform structure bone, which informs about the effects of bone microstructure on the piezoelectricity.
Wetting and motion behaviors of water droplet on graphene under thermal-electric coupling field
Authors: Zhang Zhong-Qiang , Dong Xin , Ye Hong-Fei , Cheng Guang-Gui , Ding Jian-Ning , Ling Zhi-Yong
Published: February 2015

Wetting dynamics and motion behaviors of a water droplet on graphene are characterized under the electric-thermal coupling field using classical molecular dynamics simulation method. The water droplet on graphene can be driven by the temperature gradient, while the moving direction is dependent on the electric field intensity. Concretely, the water droplet on graphene moves from the low temperature region to the high temperature region for the relatively weak electric field intensity. The motion acceleration increases with the electric field intensity on graphene, whereas the moving direction switches when the electric field intensity increases up to a threshold. The essence is the change from hydrophilic to hydrophobic for the water droplet on graphene at a threshold of the electric field intensity. Moreover, the driven force of the water droplet caused by the overall oscillation of graphene has important influence on the motion behaviors. The results are helpful to control the wettability of graphene and further develop the graphene-based fluidic nanodevices.