bluuebunny/crossref_metadata_2025 huggingface dataset:
Discovering formulaic language through data-driven learning: Student attitudes and efficacy
Authors: Geluso Joe , Yamaguchi Atsumi
Published: February 2014

Corpus linguistics has established that language is highly patterned. The use of patterned language has been linked to processing advantages with respect to listening and reading, which has implications for perceptions of fluency. The last twenty years has seen an increase in the integration of corpus-based language learning, or data-driven learning (DDL), as a supporting feature in teaching English as a foreign / second language (EFL/ESL). Most research has investigated student attitudes towards DDL as a tool to facilitate writing. Other studies, though notably fewer, have taken a quantitative perspective of the efficacy of DDL as a tool to facilitate the inductive learning of grammar rules. The purpose of this study is three-fold: (1) to present an EFL curriculum designed around DDL with the aim of improving spoken fluency; (2) to gauge how effective students were in employing newly discovered phrases in an appropriate manner; and (3) to investigate student attitudes toward such an approach to language learning. Student attitudes were investigated via a questionnaire and then triangulated through interviews and student logs. The findings indicate that students believe DDL to be a useful and effective tool in the classroom. However, students do note some difficulties related to DDL, such as encountering unfamiliar vocabulary and cut-off concordance lines. Finally, questions are raised as to the students’ ability to embed learned phrases in a pragmatically appropriate way.
The use of general and specialized corpora as reference sources for academic English writing: A case study
Authors: Chang Ji-Yeon
Published: February 2014

Corpora have been suggested as valuable sources for teaching English for academic purposes (EAP). Since previous studies have mainly focused on corpus use in classroom settings, more research is needed to reveal how students react to using corpora on their own and what should be provided to help them become autonomous corpus users, considering that their ultimate goal is to be independent scholars and writers. In the present study, conducted in an engineering lab at a Korean university over 22 weeks, data on students’ experiences and evaluations of consulting general and specialized corpora for academic writing were collected and analyzed. The findings show that, while both corpora served the participants well as reference sources, the specialized corpus was particularly valued for its direct help in academic writing because, as non-native English-speaking graduate engineering students, the participants wanted to follow the writing conventions of their discourse community. The participants also showed disparate attitudes toward the time taken for corpus consultation due to differences in factors such as academic experience, search purposes, and writing tasks. The article concludes with several suggestions for better corpus use with EAP students regarding the compilation of a corpus, corpus training, corpus competence, and academic writing.
LOGICISM, INTERPRETABILITY, AND KNOWLEDGE OF ARITHMETIC
Authors: WALSH SEAN
Published: February 2014

A crucial part of the contemporary interest in logicism in the philosophy of mathematics resides in its idea that arithmetical knowledge may be based on logical knowledge. Here, an implementation of this idea is considered that holds that knowledge of arithmetical principles may be based on two things: (i) knowledge of logical principles and (ii) knowledge that the arithmetical principles are representable in the logical principles. The notions of representation considered here are related to theory-based and structure-based notions of representation from contemporary mathematical logic. It is argued that the theory-based versions of such logicism are either too liberal (the plethora problem) or are committed to intuitively incorrect closure conditions (the consistency problem). Structure-based versions must on the other hand respond to a charge of begging the question (the circularity problem) or explain how one may have a knowledge of structure in advance of a knowledge of axioms (the signature problem). This discussion is significant because it gives us a better idea of what a notion of representation must look like if it is to aid in realizing some of the traditional epistemic aims of logicism in the philosophy of mathematics.
Birth weight and cognitive function in early adulthood: the Australian aboriginal birth cohort study
Authors: Pearce M. S. , Mann K. D. , Singh G. , Sayers S. M.
Published: February 2014

It has been suggested that in addition to genetic factors, fetal and post-natal growth influence cognition in early adulthood. However, most studies have been in developed populations, so it is unclear if the same findings would be seen in other, less developed, settings, and have used testing tools not applicable to an Australia Aboriginal population. This study investigated the relationships between cognitive function in early adulthood and birth weight and contemporary height. Simple reaction time (SRT), choice reaction time (CRT) and working memory (WM) were assessed using the CogState battery. A significant association was seen between birth weight and SRT in early adulthood, but not with the other two cognitive measures. Urban dwellers had significantly shorter SRT and CRT than their remote counterparts. Contemporary body mass index and maternal age were associated with CRT. Only fetal growth restriction was associated with WM, with greater WM in those with restricted growth. No associations were seen with contemporary height. These results suggest that fetal growth may be more important than the factors influencing post-natal growth in terms of cognition in early adulthood in this population, but that the associations may be inconsistent between cognitive outcomes. Further research is required to identify whether similar associations are seen in other, similar, populations and to assess why differences in cognitive outcome measures are seen.
Activation of TAK1 by MYD88 L265P drives malignant B-cell Growth in non-Hodgkin lymphoma
Authors: Ansell S M , Hodge L S , Secreto F J , Manske M , Braggio E , Price-Troska T , Ziesmer S , Li Y , Johnson S H , Hart S N , Kocher J-P A , Vasmatzis G , Chanan-Kahn A , Gertz M , Fonseca R , Dogan A , Cerhan J R , Novak A J
Published: February 2014

Massively parallel sequencing analyses have revealed a common mutation within the MYD88 gene (MYD88L265P) occurring at high frequencies in many non-Hodgkin lymphomas (NHLs) including the rare lymphoplasmacytic lymphoma, Waldenström’s macroglobulinemia (WM). Using whole-exome sequencing, Sanger sequencing and allele-specific PCR, we validate the initial studies and detect the MYD88L265P mutation in the tumor genome of 97% of WM patients analyzed (n=39). Due to the high frequency of MYD88 mutation in WM and other NHL, and its known effects on malignant B-cell survival, therapeutic targeting of MYD88 signaling pathways may be clinically useful. However, we are lacking a thorough characterization of the role of intermediary signaling proteins on the biology of MYD88L265P-expressing B cells. We report here that MYD88L265P signaling is constitutively active in both WM and diffuse large B-cell lymphoma cells leading to heightened MYD88L265P, IRAK and TRAF6 oligomerization and NF-κB activation. Furthermore, we have identified the signaling protein, TAK1, to be an essential mediator of MYD88L265P-driven signaling, cellular proliferation and cytokine secretion in malignant B cells. Our studies highlight the biological significance of MYD88L265P in NHL and reveal TAK1 inhibition to be a potential therapeutic strategy for the treatment of WM and other diseases characterized by MYD88L265P.
Femtoliter-scale separation and sensitive detection of nonfluorescent samples in an extended-nano fluidic device
Authors: Shimizu Hisashi , Mawatari Kazuma , Kitamori Takehiko
Published: February 2014

Liquid chromatography using a nanofluidic chip and DIC-TLM realized separation and detection of a 21 fL, 0.61 zmol nonfluorescent sample.
Isoleucine ionic liquids as additives to separate mandelic acid and their derivative enantiomers by HPLC
Authors: Zhou Jie , Zhao Suzhen , Fu Guangjun , Zhang Zhenzhong
Published: February 2014

In this study, functional isoleucine ionic liquids were synthesized and used as novel chiral ligands coordinated with Cu(ii) in chiral ligand exchange chromatography.
Fabrication and application of a copper(ii)-selective extraction disc prepared from chlorinated polyvinyl chloride and ethylenediamine-functionalized cellulose
Authors: Zhao Lianchao , Yan Hongtao , Yang Caixia , Pan Jiping
Published: February 2014

The preparation principle of a copper(ii)-selective extraction disc (Cu2+-SED) fabricated from chlorinated polyvinyl chloride (CPVC) and ethylenediamine-functionalized cellulose (cell–EDA).
Biophysical properties of nucleic acids at surfaces relevant to microarray performance
Authors: Rao Archana N. , Grainger David W.
Published: February 2014

This article reviews the properties of tethered DNA chains at surfaces required to understand and control DNA microarray assays and other biotechnologies.
Effect of phenylacetic acid coligands on the structures and magnetic properties of azido-bridged copper(ii)-chain compounds
Authors: Yang Lan , Zhang Sheng , Liu Xiangyu , Yang Qi , Wei Qing , Xie Gang , Chen Sanping
Published: February 2014

To investigate how the structures and magnetic properties of azido–copper(ii) chain compounds are influenced by substituents on the phenylacetic acid coligands, three new azido-bridged Cu(ii) compounds have been successfully obtained, and structurally and magnetically characterized.
Visualizing the atherosclerotic plaque: a chemical perspective
Authors: Teresa Albelda Ma , Garcia-España Enrique , Frias Juan C.
Published: February 2014

Compounds and imaging techniques used to visualize the atherosclerotic plaque, one of the major pathologies causing coronary artery diseases, are discussed.
Monolithic cells for solar fuels
Authors: Rongé Jan , Bosserez Tom , Martel David , Nervi Carlo , Boarino Luca , Taulelle Francis , Decher Gero , Bordiga Silvia , Martens Johan A.
Published: February 2014

A tutorial review explaining the many processes occurring in photoelectrochemical cells for solar fuel production, and prospects for future developments.
The role of carboxylato ligand dissociation in the oxidation of chrysin with H2O2 catalysed by [Mn2III,IV(μ-CH3COO)(μ-O)2(Me4dtne)](PF6)2
Authors: Abdolahzadeh Shaghayegh , Boyle Nicola M. , Hoogendijk M. Lisa , Hage Ronald , de Boer Johannes W. , Browne Wesley R.
Published: February 2014

The loss of the acetato ligand is shown to be key to the activity of this manganese catalyst at pH 11 in bleaching of chrysin.
Humidity dependency of the thermal phase transition of a cyano bridged Co–W bimetal assembly
Authors: Ozaki Noriaki , Tokoro Hiroko , Miyamoto Yasuto , Ohkoshi Shin-ichi
Published: February 2014

A three-dimensional cyano-bridged Co–W bimetal assembly shows the humidity-dependent phase transition due to desorption or absorption of water molecules.
Hydroxyapatite nanocrystals: colloidal chemistry, assembly and their biological applications
Authors: Hui Junfeng , Wang Xun
Published: February 2014

In this review, recent advances in the tunable synthesis, ion doping, assembly and applications of monodisperse HAp nanocrystals are summarized.
Mechanical property prediction of starch/polymer composites by molecular dynamics simulation
Authors: Wang Yao-Chun , Ju Shin-Pon , Chen Chien-Chia , Chen Hsin-Tsung , Hsieh Jin-Yuan
Published: February 2014

Molecular dynamics (MD) simulation was used to investigate the mechanical properties of several starch composites.
Comparison of blend morphologies of the nano-patterned photoactive films via two different techniques: thermal-assisted and solvent-assisted soft-nanoimprint lithography
Authors: Choi Jong Kil , Jin Jae Kyu , Jin Ming Liang , An Cheng Jin , Jung Hee-Tae
Published: February 2014

We reports the comparison of blend morphologies of nano-patterned photoactive films via two different techniques and its effects on the performance of OPVC.
Solvent extraction of europium(iii) to a fluorine-free ionic liquid phase with a diglycolamic acid extractant
Authors: Rout Alok , Souza Ernesto Rezende , Binnemans Koen
Published: February 2014

Bis(2-ethylhexyl)diglycolamic acid (DEHDGA) dissolved in the fluorine-free ionic liquid tetraoctylammonium dodecyl sulphate, [N8888][DS] is an efficient extractant for europium(iii).
Microemulsion-based synthesis of V1−xWxO2@SiO2 core–shell structures for smart window applications
Authors: Zhou Yijie , Ji Shidong , Li Yamei , Gao Yanfeng , Luo Hongjie , Jin Ping
Published: February 2014

Localized surface plasmon resonance in V1−xWxO2 nanoparticles can induce excellent solar regulation efficiency of thermochromic smart windows.
An electrochemical sensing platform based on local repression of electrolyte diffusion for single-step, reagentless, sensitive detection of a sequence-specific DNA-binding protein
Authors: Zhang Yun , Liu Fang , Nie Jinfang , Jiang Fuyang , Zhou Caibin , Yang Jiani , Fan Jinlong , Li Jianping
Published: February 2014

This paper describes for the first time an electrochemical biosensor, which employs a DNA probe modified with a redox tag close to electrode surface, for picomolar detection of a sequence-specific DNA-binding protein.
The influence of chloride impurities on Pt/C fuel cell catalyst corrosion
Authors: Pavlišič A. , Jovanovič P. , Šelih V. S. , Šala M. , Hodnik N. , Hočevar S. , Gaberšček M.
Published: February 2014

Potential-resolved Pt ICP-MS dissolution profiles with and without chlorides reveal new insights into platinum corrosion of fuel cell catalyst.
Pyrroles versus cyclic nitrones: catalyst-controlled divergent cyclization of N-(2-perfluoroalkyl-3-alkynyl) hydroxylamines
Authors: Zeng Qin , Zhang Li , Yang Jieru , Xu Bing , Xiao Yuanjing , Zhang Junliang
Published: February 2014

Divergent cyclizations ofN-(2-(perfluoroalkyl)-3-alkynyl) hydroxylamines1have been realized by subtle choice of the catalyst under mild conditions, leading to two distinct types of synthetic valuable compounds, cyclic nitrones2and pyrroles3, in moderate to excellent yields.
Electrophilic alkynylation of ketones using hypervalent iodine
Authors: Utaka Aline , Cavalcanti Livia N. , Silva Luiz F.
Published: February 2014

The efficient electrophilic alkynylation of ketones can be performed using hypervalent iodine compounds. This protocol was applied for an aldehyde.
A unique microporous copper trimesate selenite with high selectivity for CO2
Authors: Papaefstathiou Giannis S. , Subrahmanyam Kota S. , Armatas Gerasimos S. , Malliakas Christos D. , Kanatzidis Mercouri G. , Manos Manolis J.
Published: February 2014

The incorporation of SeO32− ligands into a copper trimesate net results in a microporous metal organic framework with highly unusual structural topology, which also shows high CO2 uptake and selectivity vs. CH4.
ortho-Dihydroxyl-9,10-anthraquinone dyes as visible-light sensitizers that exhibit a high turnover number for hydrogen evolution
Authors: Li Qin , Che Yanke , Ji Hongwei , Chen Chuncheng , Zhu Huaiyong , Ma Wanhong , Zhao Jincai
Published: February 2014

Pt/TiO2 sensitized by the cheap and organic ortho-dihydroxyl-9,10-anthraquinone dyes, such as Alizarin and Alizarin Red, achieved a TON of approximately 10 000 (TOF >250 h−1 for the first ten hours) for photocatalytic hydrogen evolution under visible light irradiation (>420 nm).
Versatile redox reactivity of triaryl-meso-substituted Ni(ii) porphyrin
Authors: Dimé Abdou K. D. , Devillers Charles H. , Cattey Hélène , Lucas Dominique
Published: February 2014

The electrochemical oxidation of a Ni(ii) tri-arylporphyrin leads to the 5-Cl and 5-OH-porphyrins, the meso–meso, meso-β and meso-β/meso-β doubly fused dimers depending on the experimental conditions. Among them, the Ni(ii) 5-Cl-porphyrin is isolated in good yield and its formation mechanism is elucidated.
A hybrid vanadium fluoride with structurally isolated S = 1 kagome layers
Authors: Aidoudi Farida H. , Downie Lewis J. , Morris Russell E. , A. de Vries Mark , Lightfoot Philip
Published: February 2014

A novel hybrid vanadium fluoride displaying isolated S = 1 kagome layers separated by ammonium and ethylammonium cations is prepared; this compound shows interesting magnetic properties.
Folic acid-functionalized AIE Pdots based on amphiphilic PCL-b-PEG for targeted cell imaging
Authors: Zhang Yan , Chen Yujue , Li Xing , Zhang Jibo , Chen Jinlong , Xu Bin , Fu Xueqi , Tian Wenjing
Published: February 2014

Folic acid-functionalized polymer dots with aggregation induced emission features (AIE Pdots), which show high fluorescence efficiency and little toxicity to living cells, which possess a good capability for targeted HeLa intracellular imaging.
Facile fabrication of nanocomposite microcapsules by combining layer-by-layer self-assembly and Pickering emulsion templating
Authors: Liu Hao , Gu Xiaoyu , Hu Meng , Hu Yang , Wang Chaoyang
Published: February 2014

Nanocomposite multilayer microcapsules are prepared by layer-by-layer self-assembly based on Pickering emulsions.
Lithium-ion storage performance of camphoric carbon wrapped NiS nano/micro-hybrids
Authors: Sebastian Sonia Theresa , Jagan Roshny Siri , Rajagoplan Ranjusha , Paravannoor Anjali , Menon Lakshmi V. , Subramanian K. R. V. , Nair Shantikumar V. , Balakrishnan Avinash
Published: February 2014

Camphoric carbon wrapped NiS powders have been profitably exploited to fabricate high surface area electrodes for Li storage.
A series of interdigitated Cd(ii) coordination polymers based on 4,6-dibenzoylisophthalic acid and flexible triazole ligands
Authors: Zhu Xiaofei , Wang Ning , Xie Xiaoyan , Hou Ruibin , Zhou Defeng , Li Yafeng , Hu Jun , Li Xinyuan , Liu He , Nie Wang
Published: February 2014

Different bridging ligands with various flexibilities and lengths were utilized to assemble interdigitated coordination polymers with Cd(ii) cations. The length and flexibility of the ligands could significantly influence the interdigitation level of the crystal structure.
A direct novel synthesis of highly uniform dispersed ruthenium nanoparticles over P6mm ordered mesoporous carbon by host–guest complexes
Authors: Gokulakrishnan N. , Peru G. , Rio S. , Blach J. F. , Léger B. , Grosso D. , Monflier E. , Ponchel A.
Published: February 2014

A nanocasting strategy to prepare Ru-ordered mesoporous carbon with uniform ruthenium dispersion is demonstrated using a β-cyclodextrin host–guest complex and RuCl3.
Beyond dsRNA: Toll-like receptor 3 signalling in RNA-induced immune responses
Authors: Tatematsu Megumi , Seya Tsukasa , Matsumoto Misako
Published: February 2014

The innate immune system recognizes pathogen- and damage-associated molecular patterns using pattern-recognition receptors that activate a wide range of signalling cascades to maintain host homoeostasis against infection and inflammation. Endosomal TLR3 (Toll-like receptor 3), a type I transmembrane protein, senses RNAs derived from cells with viral infection or sterile tissue damage, leading to the induction of type I interferon and cytokine production, as well as dendritic cell maturation. It has been accepted that TLR3 recognizes perfect dsRNA, but little has been addressed experimentally with regard to the structural features of virus- or host-derived RNAs that activate TLR3. Recently, a TLR3 agonist was identified, which was a virus-derived ‘structured’ RNA with incomplete stem structures. Both dsRNA and structured RNA are similarly internalized through clathrin- and raftlin-dependent endocytosis and delivered to endosomal TLR3. The dsRNA uptake machinery, in addition to TLR3, is critical for extracellular viral RNA-induced immune responses. A wide spectrum of TLR3 ligand structures beyond dsRNA and their delivery systems provide new insights into the physiological role of TLR3 in virus- or host-derived RNA-induced immune responses. In the present paper, we focus on the system for extracellular recognition of RNA and its delivery to TLR3.
Involvement of monocytes/macrophages as key factors in the development and progression of cardiovascular diseases
Authors: Fernández-Velasco María , González-Ramos Silvia , Boscá Lisardo
Published: February 2014

Emerging evidence points to the involvement of specialized cells of the immune system as key drivers in the pathophysiology of cardiovascular diseases. Monocytes are an essential cell component of the innate immune system that rapidly mobilize from the bone marrow to wounded tissues where they differentiate into macrophages or dendritic cells and trigger an immune response. In the healthy heart a limited, but near-constant, number of resident macrophages have been detected; however, this number significantly increases during cardiac damage. Shortly after initial cardiac injury, e.g. myocardial infarction, a large number of macrophages harbouring a pro-inflammatory profile (M1) are rapidly recruited to the cardiac tissue, where they contribute to cardiac remodelling. After this initial period, resolution takes place in the wound, and the infiltrated macrophages display a predominant deactivation/pro-resolution profile (M2), promoting cardiac repair by mediating pro-fibrotic responses. In the present review we focus on the role of the immune cells, particularly in the monocyte/macrophage population, in the progression of the major cardiac pathologies myocardial infarction and atherosclerosis.
Metformin ameliorates ovariectomy-induced vascular dysfunction in non-diabetic Wistar rats
Authors: Oliveira Phablo Wendell C. , de Sousa Glauciene J. , Caliman Izabela F. , Lamas Aline Z. , Santos de Medeiros Ana Raquel , de Andrade Tadeu U. , de Abreu Glaucia R. , de Figueiredo Suely G. , Bissoli Nazaré S.
Published: February 2014

Metformin is an antihyperglycaemic drug with pleiotropic effects that result in cardiovascular improvement. The aim of the present study was to evaluate the effects of metformin treatment on vascular dysfunction in ovariectomized rats. At 8 weeks of age, female Wistar rats were subjected to ovariectomy or a sham surgery. After 21 days, the animals were divided into three groups: SHAM (sham-operated rats), OVX (ovariectomized rats) and MET (ovariectomized rats treated with metformin at 300 mg/kg of body weight per day), and treated for 14 days. The vasorelaxation responses to ACh (acetylcholine) and SNP (sodium nitroprusside) were evaluated in mesenteric vascular beds, oxidative stress was evaluated and Western blot analysis of eNOS (endothelial NO synthase) and the NADPH oxidase Nox2 was performed. ACh-induced relaxation was reduced in the OVX group and partially restored in the MET group. L-NAME (NG-nitro-L-arginine methyl ester) attenuated and equalized the ACh-induced response in all groups. Attenuation of the ACh-induced responses by 4-aminopyridine (a blocker of voltage-gated potassium channels) was greater in the MET group compared with the OVX group. The SNP-induced responses were reduced in the OVX group and restored in the MET group. Inhibition of NADPH oxidase by apocynin (10 μM) restored the SNP-induced responses in the OVX group, enhanced these responses in the MET group and had no effect in the SHAM group. The OVX group exhibited reduced levels of eNOS protein and increased levels of oxidative stress and Nox2 protein; metformin treatment corrected all of these parameters. In conclusion, the pathophysiological changes observed in the mesenteric beds of ovariectomized rats were ameliorated by metformin. If this translates to humans, metformin could have additional benefits for post-menopausal women treated with this drug for glycaemic control.
Compensation for gravity deformation via subreflector motion of 65 m shaped Cassegrain antenna
Authors: Wang Wei , Wang Congsi , Duan Baoyan , Leng Guojun , Li Xiaoping
Published: February 2014

Compensation for degrading electromagnetic performances is one of the most important concerns for engineers involved in the structural design of a large antenna. A method is proposed to compensate the degrading electromagnetic performances induced by the main reflector deformation of the large and shaped Cassegrain antenna by adjusting the subreflector position in real time. Segmented parabola fitting based on the least squares method of the theoretical discrete data of the main shaped reflector yields a standard group of parabolic torus that is later used to fit the deformed main reflector, with all the parabolic toruses confocal in the fitting. The optimised best‐fit parameters and the matching between the main reflector and subreflector calculate the adjustment quantity of the subreflector. The adjustment quantities, stored in the database of the subreflector, working under various conditions can be called in real time to compensate the gravity deformation of the main reflector. The application of the method to a 65 m aperture‐reflector antenna was successful, thus, laying a good foundation for its application in engineering practice.
Combined‐element frequency selective surfaces with multiple transmission poles and zeros
Authors: Wang Desong , Che Wenquan , Chang Yumei , Chin Kuo‐Sheng , Chow Yung‐Leonard
Published: February 2014

A novel combined‐element frequency selective surface (FSS) is proposed for multi‐band applications. In this design, complementary square loops and meandering slots are combined to construct the composite FSS. The proposed FSS provides three transmission poles and two transmission zeros, transmitting the desired signals at 8.5, 11 and 16 GHz while reflecting the unnecessary signals at 9.6 and 13.1 GHz. This FSS has the advantages of flexible and simple structure, easy processing and low profile compared with traditional multi‐pole FSSs. The design strategy of the proposed FSS and the associated equivalent circuit model are provided to analyse the frequency characteristics. A prototype is fabricated and measured, showing a superior and stable frequency response in case of oblique incidence for both the transverse‐electric (TE) and transverse‐magnetic (TM) polarisations. Good agreement between the simulated and measured results is observed. Finally, the higher‐order FSS with good frequency selectivity is investigated.
Reclaiming Revolutionary Feminism
Authors: Mackay Finn
Published: February 2014

Generally, saying: ‘feminist’, is revolutionary enough in this day and age, it's far more of a statement now than it was back in the eighties. And no, I wouldn't say I was a Revolutionary Feminist now ‘cos I'm less separatist than I was at that time and I think it's got overladen with such baggage that I'd have to spend about ten minutes defining what I meant. (Interview with Al Garthwaite, Leeds, 20 January 2012)
Existence and uniqueness of domain wall solitons in a Maxwell–Chern–Simons model
Authors: Zhang Ruifeng , Li Fangfang
Published: February 2014

We present some sharp existence and uniqueness theorems for the domain wall solutions of the basic governing equations of a self-dual Maxwell–Chern–Simons model.
Ferrimagnetism of dilute Ising antiferromagnets
Authors: Timonin P. N.
Published: February 2014

It is shown that nearest-neighbor antiferromagnetic interactions of identical Ising spins on unbalanced bipartite lattice and imbalanced bipartite hierarchical fractal result in ferrimagnetic order instead of anti-ferromagnetic one. On some crystal lattices dilute Ising antiferromagnets may also become ferrimagnets due to the imbalanced nature of the magnetic percolation cluster when it coexists with the percolation cluster of vacancies. As evidenced by the existing experiments on FepZn1−pF2, such ferrimagnetism is inherent property of bcc lattice so thermodynamics of these compounds at low p can be similar to that of antiferromagnet on imbalanced hierarchical fractal.
Spin-orbit interaction in the supersymmetric antiferromagnetic t-J chain with a magnetic impurity
Authors: Zvyagin A. A.
Published: February 2014

The effect of spin-orbit interaction in the strongly correlated exactly solvable electron model with magnetic impurity is studied. The considered magnetic impurity reveals the property of a “mobile” one. It is shown that the asymptotics of correlation functions, calculated in the framework of the conformal field theory and finite size corrections of the Bethe ansatz exact solution, are strongly affected by both, the spin-orbit coupling, and by the magnetic impurity.
Dynamics of asymmetric binary glass formers. I. A dielectric and nuclear magnetic resonance spectroscopy study
Authors: Kahlau R. , Bock D. , Schmidtke B. , Rössler E. A.
Published: February 2014

Dielectric spectroscopy as well as 2H and 31P nuclear magnetic resonance spectroscopy (NMR) are applied to probe the component dynamics of the binary glass former tripropyl phosphate (TPP)/polystyrene (PS/PS-d3) in the full concentration (cTPP) range. In addition, depolarized light scattering and differential scanning calorimetry experiments are performed. Two glass transition temperatures are found: Tg1(cTPP) reflects PS dynamics and shows a monotonic plasticizer effect, while the lower Tg2(cTPP) exhibits a maximum and is attributed to (faster) TPP dynamics, occurring in a slowly moving or immobilized PS matrix. Dielectric spectroscopy probing solely TPP identifies two different time scales, which are attributed to two sub-ensembles. One of them, again, shows fast TPP dynamics (α2-process), the other (α1-process) displays time constants identical with those of the slow PS matrix. Upon heating the α1-fraction of TPP decreases until above some temperature Tc only a single α2-population exists. Inversely, below Tc a fraction of the TPP molecules is trapped by the PS matrix. At low cTPP the α2-relaxation does not follow frequency-temperature superposition (FTS), instead it is governed by a temperature independent distribution of activation energies leading to correlation times which follow Arrhenius laws, i.e., the α2-relaxation resembles a secondary process. Yet, 31P NMR demonstrates that it involves isotropic reorientations of TPP molecules within a slowly moving or rigid matrix of PS. At high cTPP the super-Arrhenius temperature dependence of τ2(T), as well as FTS are recovered, known as typical of the glass transition in neat systems.
Defect mode properties of two-dimensional plasma-filled defective metallic photonic crystal
Authors: Fu T. , Yang Z. , Tang X. , Shi Z. , Lan F.
Published: February 2014

This paper studies the frequency and amplitude properties of a defect mode which is only in a plasma-filled metallic photonic crystal with defect layer. Results show that the frequency almost has no change and the amplitude declines gradually with the growth of the number of the layers. The frequency of the defect mode not only can be modulated by filling ratio but also can be tuned by plasma density without modifying the structure. The amplitude can be modified by plasma angular frequency as well. These characteristics provide a foundation to design tunable filters, high power millimeter devices.
Competitive autocatalytic reactions in chaotic flows with diffusion: Prediction using finite-time Lyapunov exponents
Authors: Schlick Conor P. , Umbanhowar Paul B. , Ottino Julio M. , Lueptow Richard M.
Published: February 2014

We investigate chaotic advection and diffusion in autocatalytic reactions for time-periodic sine flow computationally using a mapping method with operator splitting. We specifically consider three different autocatalytic reaction schemes: a single autocatalytic reaction, competitive autocatalytic reactions, which can provide insight into problems of chiral symmetry breaking and homochirality, and competitive autocatalytic reactions with recycling. In competitive autocatalytic reactions, species B and C both undergo an autocatalytic reaction with species A such that A+B→2B and A+C→2C. Small amounts of initially spatially localized B and C and a large amount of spatially homogeneous A are advected by the velocity field, diffuse, and react until A is completely consumed and only B and C remain. We find that local finite-time Lyapunov exponents (FTLEs) can accurately predict the final average concentrations of B and C after the reaction completes. The species that starts in the region with the larger FTLE has, with high probability, the larger average concentration at the end of the reaction. If B and C start in regions with similar FTLEs, their average concentrations at the end of the reaction will also be similar. When a recycling reaction is added, the system evolves towards a single species state, with the FTLE often being useful in predicting which species fills the entire domain and which is depleted. The FTLE approach is also demonstrated for competitive autocatalytic reactions in journal bearing flow, an experimentally realizable flow that generates chaotic dynamics.
Size-extensivity-corrected multireference configuration interaction schemes to accurately predict bond dissociation energies of oxygenated hydrocarbons
Authors: Oyeyemi Victor B. , Krisiloff David B. , Keith John A. , Libisch Florian , Pavone Michele , Carter Emily A.
Published: February 2014

Oxygenated hydrocarbons play important roles in combustion science as renewable fuels and additives, but many details about their combustion chemistry remain poorly understood. Although many methods exist for computing accurate electronic energies of molecules at equilibrium geometries, a consistent description of entire combustion reaction potential energy surfaces (PESs) requires multireference correlated wavefunction theories. Here we use bond dissociation energies (BDEs) as a foundational metric to benchmark methods based on multireference configuration interaction (MRCI) for several classes of oxygenated compounds (alcohols, aldehydes, carboxylic acids, and methyl esters). We compare results from multireference singles and doubles configuration interaction to those utilizing a posteriori and a priori size-extensivity corrections, benchmarked against experiment and coupled cluster theory. We demonstrate that size-extensivity corrections are necessary for chemically accurate BDE predictions even in relatively small molecules and furnish examples of unphysical BDE predictions resulting from using too-small orbital active spaces. We also outline the specific challenges in using MRCI methods for carbonyl-containing compounds. The resulting complete basis set extrapolated, size-extensivity-corrected MRCI scheme produces BDEs generally accurate to within 1 kcal/mol, laying the foundation for this scheme's use on larger molecules and for more complex regions of combustion PESs.
Gate dielectric degradation: Pre-existing vs. generated defects
Authors: Veksler Dmitry , Bersuker Gennadi
Published: February 2014

We consider the possibility that degradation of the electrical characteristics of high-k gate stacks under low voltage stresses of practical interest is caused primarily by activation of pre-existing defects rather than generation of new ones. In nFETs in inversion, in particular, defect activation is suggested to be associated with the capture of an injected electron: in this charged state, defects can participate in a fast exchange of charge carriers with the carrier reservoir (substrate or gate electrode) that constitutes the physical process underlying a variety of electrical measurements. The degradation caused by the activation of pre-existing defects, as opposed to that of new defect generation, is both reversible and exhibits a tendency to saturate through the duration of stress. By using the multi-phonon assisted charge transport description, it is demonstrated that the trap activation concept allows reproducing a variety of experimental results including stress time dependency of the threshold voltage, leakage current, charge pumping current, and low frequency noise. Continuous, long-term degradation described by the power law time dependency is shown to be determined by the activation of defects located in the interfacial SiO2 layer of the high-k gate stacks. The findings of this study can direct process optimization efforts towards reduction of as-grown precursors of the charge trapping defects as the major factor affecting reliability.
Dispersion potential between three-bodies with arbitrary electric multipole polarizabilities: Molecular QED theory
Authors: Salam A.
Published: February 2014

Molecular quantum electrodynamics is used to obtain an expression for the retarded dispersion energy shift between three arbitrarily electrically polarizable atoms or molecules. A generalized Craig-Power Hamiltonian that depends quadratically on the electric displacement field is employed together with third-order diagrammatic perturbation theory. This approach simplifies the calculation relative to the use of the usual multipolar coupling Hamiltonian that is linear in the displacement field. Specific higher multipole non-additive contributions are then extracted. These include dipole-dipole-quadrupole, dipole-quadrupole-quadrupole, and dipole-dipole-octupole potentials valid for oriented and isotropic species with arbitrary separation distances between particles, extending recent work in which these energy shifts were given for equilateral triangle and collinear geometries. Near-zone limiting forms are found to agree with earlier works in which static inter-particle couplings were used.
Magnetic properties of nano-scale hematite, α-Fe2O3, studied by time-of-flight inelastic neutron spectroscopy
Authors: Hill Adrian H. , Jacobsen Henrik , Stewart J. Ross , Jiao Feng , Jensen Niels P. , Holm Sonja L. , Mutka Hannu , Seydel Tilo , Harrison Andrew , Lefmann Kim
Published: February 2014

Samples of nanoscale hematite, α-Fe2O3, with different surface geometries and properties have been studied with inelastic time-of-flight neutron scattering. The 15 nm diameter nanoparticles previously shown to have two collective magnetic excitation modes in separate triple-axis neutron scattering studies have been studied in further detail using the advantage of a large detector area, high resolution, and large energy transfer range of the IN5 TOF spectrometer. A mesoporous hematite sample has also been studied, showing similarities to that of the nanoparticle sample and bulk α-Fe2O3. Analysis of these modes provides temperature dependence of the magnetic anisotropy coefficient along the c-axis, κ1. This is shown to remain negative throughout the temperature range studied in both samples, providing an explanation for the previously observed suppression of the Morin transition in the mesoporous material. The values of this anisotropy coefficient are found to lie between those of bulk and nano-particulate samples, showing the hybrid nature of the mesoporous 3-dimensional structure.
Spin wave spectra and spatially modulated structures in BiFeO3
Authors: Popkov A. F. , Kulagin N. E. , Soloviov S. V. , Gareeva Z. V. , Zvezdin A. K.
Published: February 2014

The spin wave spectra of antiferromagnetic BiFeO3-type multiferronics are analyzed theoretically. The presence of a spatially modulated cycloidal antiferromagnetic structure leads to a countable number of frequency branches of two oscillatory modes (Goldstone and activation) for spin waves propagating along a cycloid. When there is no magnetic field and anisotropy, the magnon spectrum is characterized by the absence of frequency gaps. The spectral features of the spin oscillations with changing anisotropy and application of a magnetic field are identified and the limits on the existence of an antiferromagnetic cycloid are established up to its transformation into a conical structure. In the transverse direction the spin oscillations have a mixed character which indicates that the cycloid is stable with respect to bending throughout its domain of existence.
Quantum entanglement and quantum discord in magnetoactive materials (Review Article)
Authors: Aldoshin S. M. , Fel'dman E. B. , Yurishchev M. A.
Published: February 2014

We review the concepts of quantum entanglement and quantum discord and present the entropic measures for these information correlations. We further provide examples demonstrating the presence of quantum information correlations in different paramagnetic materials with ferro- and antiferromagnetic coupling. The temperature behavior of the discord for atomic nuclear spins and decoherence of quantum states with electron and nuclear spins is discussed.
Peculiarities of the resonant transmission of a TM (TE) wave through an antiferromagnet plate in crossed dc magnetic and electric fields
Authors: Levchenko G. G. , Savchenko A. S. , Tarasenko A. S. , Tarasenko S. V. , Shavrov V. G.
Published: February 2014

We studied the relation between the topological characteristics of a refraction surface and the characteristics of the transmission of a TM or TE bulk electromagnetic wave through a transparent half-wave antiferromagnet plate in crossed dc magnetic and electric fields. It was shown that the conditions for resonant transmission correspond to the spectrum of escaping bulk magnetic polaritons of the layer as well as the spectrum of electromagnetic waves in the plate with extreme values of the surface impedance.
Separating strain from composition in unit cell parameter maps obtained from aberration corrected high resolution transmission electron microscopy imaging
Authors: Schulz T. , Duff A. , Remmele T. , Korytov M. , Markurt T. , Albrecht M. , Lymperakis L. , Neugebauer J. , Chèze C. , Skierbiszewski C.
Published: February 2014

Based on the evaluation of lattice parameter maps in aberration corrected high resolution transmission electron microscopy images, we propose a simple method that allows quantifying the composition and disorder of a semiconductor alloy at the unit cell scale with high accuracy. This is realized by considering, next to the out-of-plane, also the in-plane lattice parameter component allowing to separate the chemical composition from the strain field. Considering only the out-of-plane lattice parameter component not only yields large deviations from the true local alloy content but also carries the risk of identifying false ordering phenomena like formations of chains or platelets. Our method is demonstrated on image simulations of relaxed supercells, as well as on experimental images of an In0.20Ga0.80N quantum well. Principally, our approach is applicable to all epitaxially strained compounds in the form of quantum wells, free standing islands, quantum dots, or wires.
Surface optical phonons in GaAs nanowires grown by Ga-assisted chemical beam epitaxy
Authors: García Núñez C. , Braña A. F. , Pau J. L. , Ghita D. , García B. J. , Shen G. , Wilbert D. S. , Kim S. M. , Kung P.
Published: February 2014

Surface optical (SO) phonons were studied by Raman spectroscopy in GaAs nanowires (NWs) grown by Ga-assisted chemical beam epitaxy on oxidized Si(111) substrates. NW diameters and lengths ranging between 40 and 65 nm and between 0.3 and 1.3 μm, respectively, were observed under different growth conditions. The analysis of the Raman peak shape associated to either longitudinal or surface optical modes gave important information about the crystal quality of grown NWs. Phonon confinement model was used to calculate the density of defects as a function of the NW diameter resulting in values between 0.02 and 0.03 defects/nm, indicating the high uniformity obtained on NWs cross section size during growth. SO mode shows frequency downshifting as NW diameter decreases, this shift being sensitive to NW sidewall oxidation. The wavevector necessary to activate SO phonon was used to estimate the NW facet roughness responsible for SO shift.
Approaching the complete basis set limit of CCSD(T) for large systems by the third-order incremental dual-basis set zero-buffer F12 method
Authors: Zhang Jun , Dolg Michael
Published: February 2014

The third-order incremental dual-basis set zero-buffer approach was combined with CCSD(T)-F12x (x = a, b) theory to develop a new approach, i.e., the inc3-db-B0-CCSD(T)-F12 method, which can be applied as a black-box procedure to efficiently obtain the near complete basis set (CBS) limit of the CCSD(T) energies also for large systems. We tested this method for several cases of different chemical nature: four complexes taken from the standard benchmark sets S66 and X40, the energy difference between isomers of water hexamer and the rotation barrier of biphenyl. The results show that our method has an error relative to the best estimation of CBS energy of only 0.2 kcal/mol or less. By parallelization, our method can accomplish the CCSD(T)-F12 calculations of about 60 correlated electrons and 800 basis functions in only several days, which by standard implementation are impossible for ordinary hardware. We conclude that the inc3-db-B0-CCSD(T)-F12a/AVTZ method, which is of CCSD(T)/AV5Z quality, is close to the limit of accuracy that one can achieve for large systems currently.
A density functional theory model of mechanically activated silyl ester hydrolysis
Authors: Pill Michael F. , Schmidt Sebastian W. , Beyer Martin K. , Clausen-Schaumann Hauke , Kersch Alfred
Published: February 2014

To elucidate the mechanism of the mechanically activated dissociation of chemical bonds between carboxymethylated amylose (CMA) and silane functionalized silicon dioxide, we have investigated the dissociation kinetics of the bonds connecting CMA to silicon oxide surfaces with density functional calculations including the effects of force, solvent polarizability, and pH. We have determined the activation energies, the pre-exponential factors, and the reaction rate constants of candidate reactions. The weakest bond was found to be the silyl ester bond between the silicon and the alkoxy oxygen atom. Under acidic conditions, spontaneous proton addition occurs close to the silyl ester such that neutral reactions become insignificant. Upon proton addition at the most favored position, the activation energy for bond hydrolysis becomes 31 kJ mol−1, which agrees very well with experimental observation. Heterolytic bond scission in the protonated molecule has a much higher activation energy. The experimentally observed bi-exponential rupture kinetics can be explained by different side groups attached to the silicon atom of the silyl ester. The fact that different side groups lead to different dissociation kinetics provides an opportunity to deliberately modify and tune the kinetic parameters of mechanically activated bond dissociation of silyl esters.
The far-infrared spectrum of azulene and isoquinoline and supporting anharmonic density functional theory calculations to high resolution spectroscopy of polycyclic aromatic hydrocarbons and derivatives
Authors: Goubet Manuel , Pirali Olivier
Published: February 2014

In the laboratory, the acquisition and analysis of the rotationally resolved spectra of large molecular systems remain challenging. We report in this paper the rotational analysis of the ν30-GS band of azulene and the ν41-GS band of isoquinoline recorded with synchrotron-based Fourier transform absorption spectroscopy in the far-IR. As a support to rotational analyses, we employed a method based on standard density functional theory calculations performed at the anharmonic level which accurately reproduced the rotational constants of 28 vibrational states of 16 Polycyclic Aromatic Hydrocarbons (PAHs) and aza-derivatives. This method appears as an invaluable support for the spectral assignment of the very congested rotational structures of the infrared bands of PAH species and should be very helpful in the active search of these molecules in space through their pure rotational or rovibrational spectra.