bluuebunny/crossref_metadata_2025 huggingface dataset:
Hyperspectral light sheet microscopy
Authors: Jahr Wiebke , Schmid Benjamin , Schmied Christopher , Fahrbach Florian O. , Huisken Jan
Published: September 2015

To study the development and interactions of cells and tissues, multiple fluorescent markers need to be imaged efficiently in a single living organism. Instead of acquiring individual colours sequentially with filters, we created a platform based on line-scanning light sheet microscopy to record the entire spectrum for each pixel in a three-dimensional volume. We evaluated data sets with varying spectral sampling and determined the optimal channel width to be around 5 nm. With the help of these data sets, we show that our setup outperforms filter-based approaches with regard to image quality and discrimination of fluorophores. By spectral unmixing we resolved overlapping fluorophores with up to nanometre resolution and removed autofluorescence in zebrafish and fruit fly embryos.
A multimodal MRI dataset of professional chess players
Authors: Li Kaiming , Jiang Jing , Qiu Lihua , Yang Xun , Huang Xiaoqi , Lui Su , Gong Qiyong
Published: September 2015

Chess is a good model to study high-level human brain functions such as spatial cognition, memory, planning, learning and problem solving. Recent studies have demonstrated that non-invasive MRI techniques are valuable for researchers to investigate the underlying neural mechanism of playing chess. For professional chess players (e.g., chess grand masters and masters or GM/Ms), what are the structural and functional alterations due to long-term professional practice, and how these alterations relate to behavior, are largely veiled. Here, we report a multimodal MRI dataset from 29 professional Chinese chess players (most of whom are GM/Ms), and 29 age matched novices. We hope that this dataset will provide researchers with new materials to further explore high-level human brain functions.
Regional paleofire regimes affected by non-uniform climate, vegetation and human drivers
Authors: Blarquez Olivier , Ali Adam A. , Girardin Martin P. , Grondin Pierre , Fréchette Bianca , Bergeron Yves , Hély Christelle
Published: September 2015

Climate, vegetation and humans act on biomass burning at different spatial and temporal scales. In this study, we used a dense network of sedimentary charcoal records from eastern Canada to reconstruct regional biomass burning history over the last 7000 years at the scale of four potential vegetation types: open coniferous forest/tundra, boreal coniferous forest, boreal mixedwood forest and temperate forest. The biomass burning trajectories were compared with regional climate trends reconstructed from general circulation models, tree biomass reconstructed from pollen series and human population densities. We found that non-uniform climate, vegetation and human drivers acted on regional biomass burning history. In the open coniferous forest/tundra and dense coniferous forest, the regional biomass burning was primarily shaped by gradual establishment of less climate-conducive burning conditions over 5000 years. In the mixed boreal forest an increasing relative proportion of flammable conifers in landscapes since 2000 BP contributed to maintaining biomass burning constant despite climatic conditions less favourable to fires. In the temperate forest, biomass burning was uncoupled with climatic conditions and the main driver was seemingly vegetation until European colonization, i.e. 300 BP. Tree biomass and thus fuel accumulation modulated fire activity, an indication that biomass burning is fuel-dependent and notably upon long-term co-dominance shifts between conifers and broadleaf trees.
Experimental Demonstration of a Synthetic Lorentz Force by Using Radiation Pressure
Authors: Šantić N. , Dubček T. , Aumiler D. , Buljan H. , Ban T.
Published: September 2015

Synthetic magnetism in cold atomic gases opened the doors to many exciting novel physical systems and phenomena. Ubiquitous are the methods used for the creation of synthetic magnetic fields. They include rapidly rotating Bose-Einstein condensates employing the analogy between the Coriolis and the Lorentz force and laser-atom interactions employing the analogy between the Berry phase and the Aharonov-Bohm phase. Interestingly, radiation pressure - being one of the most common forces induced by light - has not yet been used for synthetic magnetism. We experimentally demonstrate a synthetic Lorentz force, based on the radiation pressure and the Doppler effect, by observing the centre-of-mass motion of a cold atomic cloud. The force is perpendicular to the velocity of the cold atomic cloud and zero for the cloud at rest. Our novel concept is straightforward to implement in a large volume, for a broad range of velocities and can be extended to different geometries.
Correction: Corrigendum: Novel anti-thrombotic agent for modulation of protein disulfide isomerase family member ERp57 for prophylactic therapy
Authors: Cui Guozhen , Shan Luchen , Guo Lin , Keung Chu Ivan , Li Guohui , Quan Quan , Zhao Yun , Meng Chong Cheong , Zhang Zaijun , Yu Pei , Hoi Maggie Pui Man , Sun Yewei , Wang Yuqiang , Lee Simon MingYuen
Published: September 2015

Protein disulfide isomerase (PDI) family members including PDI and ERp57 emerge as novel targets for anti-thrombotic treatments, but chemical agents with selectivity remain to be explored. We previously reported a novel derivative of danshensu (DSS), known as ADTM, displayed strong cardioprotective effects against oxidative stress-induced cellular injury in vitro and acute myocardial infarct in vivo. Herein, using chemical proteomics approach, we identified ERp57 as a major target of ADTM. ADTM displayed potent inhibitory effects on the redox activity of ERp57, inhibited the adenosine diphosphate (ADP)-induced expressions of P-selectin and αIIbβ3 integrin, and disrupted the interaction between ERp57 and αIIbβ3. In addition, ADTM inhibited both arachidonic acid (AA)-induced and ADP-induced platelet aggregation in vitro. Furthermore, ADTM significantly inhibited rat platelet aggregation and thrombus formation in vivo. Taken together, ADTM represents a promising candidate for anti-thrombotic therapy targeting ERp57.
Ultralow threading dislocation density in GaN epilayer on near-strain-free GaN compliant buffer layer and its applications in hetero-epitaxial LEDs
Authors: Shih Huan-Yu , Shiojiri Makoto , Chen Ching-Hsiang , Yu Sheng-Fu , Ko Chung-Ting , Yang Jer-Ren , Lin Ray-Ming , Chen Miin-Jang
Published: September 2015

High threading dislocation (TD) density in GaN-based devices is a long unresolved problem because of the large lattice mismatch between GaN and the substrate, which causes a major obstacle for the further improvement of next-generation high-efficiency solid-state lighting and high-power electronics. Here, we report InGaN/GaN LEDs with ultralow TD density and improved efficiency on a sapphire substrate, on which a near strain-free GaN compliant buffer layer was grown by remote plasma atomic layer deposition. This “compliant” buffer layer is capable of relaxing strain due to the absorption of misfit dislocations in a region within ~10 nm from the interface, leading to a high-quality overlying GaN epilayer with an unusual TD density as low as 2.2 × 105 cm−2. In addition, this GaN compliant buffer layer exhibits excellent uniformity up to a 6” wafer, revealing a promising means to realize large-area GaN hetero-epitaxy for efficient LEDs and high-power transistors.
RETRACTED ARTICLE: MircoRNA-33a inhibits epithelial-to-mesenchymal transition and metastasis and could be a prognostic marker in non-small cell lung cancer
Authors: Yang Lihua , Yang Jie , Li Jingqiu , Shen Xingkai , Le Yanping , Zhou Chengwei , Wang Shaomin , Zhang Shun , Xu Dazhi , Gong Zhaohui
Published: September 2015

Understanding the molecular mechanism by which epithelial mesenchymal transition (EMT)-mediated cancer metastasis and how microRNA (miRNA) regulates lung cancer progression via Twist1-activated EMT may provide potential therapeutic targets for cancer therapy. Here we found that miR-33a, an intronic miRNA located within the sterol regulatory element-binding protein 2 (SREBP-2) gene, is expressed at low levels in metastatic non-small cell lung cancer (NSCLC) cells and is inversely correlated with Twist1 expression. Conversely, miR-33a knockdown induces EMT and miR-33a overexpression blocks EMT by regulating of Twist1 expression in NSCLC cells. Bioinformatical prediction and luciferase reporter assay confirm that Twist1 is a direct target of miR-33a. Additionally, Twist1 knockdown blocks EMT-related metastasis and forced expression of miR-33a inhibits lung cancer metastasis in a xenograft animal model. Clinically, miR-33a is found to be at low levels in NSCLC patients and down-regulation of miR-33a predicts a poor prognosis. These findings suggest that miR-33a targets Twist1 and inhibits invasion and metastasis in NSCLC. Thus, miR-33a might be a potential prognostic marker and of therapeutic relevance for NSCLC metastasis intervention.
Inversed Vernier effect based single-mode laser emission in coupled microdisks
Authors: Li Meng , Zhang Nan , Wang Kaiyang , Li Jiankai , Xiao Shumin , Song Qinghai
Published: September 2015

Recently, on-chip single-mode laser emissions in coupled microdisks have attracted considerable research attention due to their wide applications. While most of single-mode lasers in coupled microdisks or microrings have been qualitatively explained by either Vernier effect or inversed Vernier effect, none of them have been experimentally confirmed. Here, we studied the mechanism of single-mode laser operation in coupled microdisks. We found that the mode numbers had been significantly reduced to nearly single-mode within a large pumping power range from threshold to gain saturation. The detail laser spectra showed that the largest gain and the first lasing peak were mainly generated by one disk and the laser intensity was proportional to the wavelength detuning of two set of modes. The corresponding theoretical analysis showed that the experimental observations were dominated by internal coupling within one cavity, which was similar to the recently explored inversed Vernier effect in two coupled microrings. We believe our finding will be important for understanding the previous experimental findings and the development of on-chip single-mode laser.
The roles of Eu during the growth of eutectic Si in Al-Si alloys
Authors: Li Jiehua , Hage Fredrik , Wiessner Manfred , Romaner Lorenz , Scheiber Daniel , Sartory Bernhard , Ramasse Quentin , Schumacher Peter
Published: September 2015

Controlling the growth of eutectic Si and thereby modifying the eutectic Si from flake-like to fibrous is a key factor in improving the properties of Al-Si alloys. To date, it is generally accepted that the impurity-induced twinning (IIT) mechanism and the twin plane re-entrant edge (TPRE) mechanism as well as poisoning of the TPRE mechanism are valid under certain conditions. However, IIT, TPRE or poisoning of the TPRE mechanism cannot be used to interpret all observations. Here, we report an atomic-scale experimental and theoretical investigation on the roles of Eu during the growth of eutectic Si in Al-Si alloys. Both experimental and theoretical investigations reveal three different roles: (i) the adsorption at the intersection of Si facets, inducing IIT mechanism, (ii) the adsorption at the twin plane re-entrant edge, inducing TPRE mechanism or poisoning of the TPRE mechanism and (iii) the segregation ahead of the growing Si twins, inducing a solute entrainment within eutectic Si. This investigation not only demonstrates a direct experimental support to the well-accepted poisoning of the TPRE and IIT mechanisms, but also provides a full picture about the roles of Eu atoms during the growth of eutectic Si, including the solute entrainment within eutectic Si.
Nanostructured SnS-N-doped graphene as an advanced electrocatalyst for the hydrogen evolution reaction
Authors: Shinde S. S. , Sami Abdul , Kim Dong-Hyung , Lee Jung-Ho
Published: September 2015

The scalable hydrothermal synthesis of the SnS/N-rGr hybrid is presented for the first time, which is used as a highly-active electrocatalyst with long-term stability in different media.
Highly efficient photocatalytic degradation of organic dyes by Cu doped ZnO nanostructures
Authors: Kuriakose Sini , Satpati Biswarup , Mohapatra Satyabrata
Published: September 2015

Cu doped ZnO nanostructures exhibit highly efficient sunlight driven photocatalytic activity for degradation of methylene blue and methyl orange dyes.
Open quantum system parameters for light harvesting complexes from molecular dynamics
Authors: Wang Xiaoqing , Ritschel Gerhard , Wüster Sebastian , Eisfeld Alexander
Published: September 2015

We elucidate the difference between various parameter extraction methods and demonstrate sensitivity to molecular dynamics equilibration.
Branching ratios for the reactions of OH with ethanol amines used in carbon capture and the potential impact on carcinogen formation in the emission plume from a carbon capture plant
Authors: Onel L. , Blitz M. A. , Breen J. , Rickard A. R. , Seakins P. W.
Published: September 2015

Branching ratios for the OH reaction with ethanol amines and potential risk of carcinogenic formation in the carbon capture plume.
Fluoride-free Hiyama coupling by palladium abnormal N-heterocyclic carbene complexes
Authors: Modak Sudipta , Gangwar Manoj Kumar , Nageswar Rao Mitta , Madasu Mahesh , Kalita Alok Ch. , Dorcet Vincent , Shejale Mayuri Arun , Butcher Ray J. , Ghosh Prasenjit
Published: September 2015

A series of Pd complexes of the 1,2,3-triazole based abnormal NHC ligands of the type (a-NHC)PdI2(L) [L = NC5H5and PPh3] successfully catalyzed the fluoride-free Hiyama coupling in air.
Evaluation of residual antibacterial potency in antibiotic production wastewater using a real-time quantitative method
Authors: Zhang Hong , Zhang Yu , Yang Min , Liu Miaomiao
Published: September 2015

While antibiotic pollution has attracted considerable attention due to its potential in promoting the dissemination of antibiotic resistance genes in the environment, the antibiotic activity of their related substances has been neglected, which may underestimate the environmental impacts of antibiotic wastewater discharge.
Design, synthesis and bioevaluation of tacrine hybrids with cinnamate and cinnamylidene acetate derivatives as potential anti-Alzheimer drugs
Authors: Quintanova Catarina , Keri Rangappa S. , Marques Sérgio M. , G-Fernandes Maria , Cardoso Sandra M. , Luísa Serralheiro M. , Amélia Santos M.
Published: September 2015

Novel tacrine–cinnamate and –cinnamylidenacetate as multitargeted compounds in view of AD drugs: anti-AChE and anti-oxidant activity as well as cell neuroprotection.
Temporal wetting property of “Micro” versus “Nano” rods of ZnO grown using the pressure dependent aqueous solution method
Authors: Behera Akshaya K. , Das Pritam , Thakur Indrani , Chatterjee Sriparna , Chatterjee Shyamal
Published: September 2015

Study of temporal wetting properties of micro- and nano-rods of zinc oxide.
PB@Co3O4 nanoparticles as both oxidase and peroxidase mimics and their application for colorimetric detection of glutathione
Authors: Yang Wenshu , Hao Jinhui , Zhang Zhe , Zhang Bailin
Published: September 2015

Co3O4-modified Prussian blue nanocubes (PB@Co3O4) were obtained by using a water-bath method and were found to exhibit both intrinsic oxidase-like and peroxidase-like activities.
Ion insertion into individual 7,7,8,8-tetracyanoquinodimethane nanoparticles
Authors: Zhou X. F. , Cheng W. , Compton R. G.
Published: September 2015

Potassium and sodium ion insertion were quantitatively analysed at the single individual nanoparticle level with a limiting ion insertion mechanism proposed.
D–A copolymers containing lactam moieties for polymer solar cells
Authors: Lu Futai , Qian Liu , Cao Jiamin , Feng Yaqing , Du Bin , Ding Liming
Published: September 2015

D–A copolymersP1andP2containing a new lactam acceptor unit BDTP and BDT or selenophene as a donor unit gave PCEs of 5.05% and 6.76%, respectively.
Increasing the surface area of TiO2 nanotube membranes by filling the channels with onion type carbon materials and TiCl4 for dye-sensitized solar cells
Authors: Kim Ho-sub , Suh Jung Sang
Published: September 2015

We have significantly enhanced the power conversion efficiency of dye-sensitized solar cells based on TiO2 nanotube membranes by increasing the inner surface area of the channels.
Kinetic study of DNA hybridization on DNA-modified gold nanoparticles with engineered nano-interfaces
Authors: Takashima Akari , Oishi Motoi
Published: September 2015

We report a systematic study of DNA hybridization kinetics on GNPs with probe DNA and different molecular weight PEGs, and protruding structure of probe DNA from the PEG layer is the key factors for DNA hybridization on GNPs.
A facile approach to construct BiOI/Bi5O7I composites with heterostructures: efficient charge separation and enhanced photocatalytic activity
Authors: Yu Yaoguang , Chen Gang , Wang Xu , Jia Dechang , Tang Pengxiao , Lv Chade
Published: September 2015

A series of BiOI/Bi5O7I composite photocatalysts with heterostructures was successfully synthetized through a facile hydrothermal method.
The investigation of ESPT for 2,8-diphenyl-3,7-dihydroxy-4H,6H-pyrano[3,2-g]-chromene-4,6-dione: single or double?
Authors: Zhao Jinfeng , Li Peng
Published: September 2015

The dynamic overall perspective of an excited-state proton transfer (ESPT) process for 2,8-diphenyl-3,7-dihydroxy-4H,6H-pyrano[3,2-g]-chromene-4,6-dione (D3HF) is investigated based on a time-dependent density functional theory (TDDFT) method.
Removal of safranin-O dye from aqueous solution using modified red mud: kinetics and equilibrium studies
Authors: Sahu Manoj Kumar , Patel Raj Kishore
Published: September 2015

Adsorption of safranin-O dye on SDS modified red mud at different pH.
Harmonized tuning of nucleic acid and lectin binding properties with multivalent cyclodextrins for macrophage-selective gene delivery
Authors: Méndez-Ardoy Alejandro , Díaz-Moscoso Alejandro , Ortiz Mellet Carmen , Di Giorgio Christophe , Vierling Pierre , Benito Juan M. , García Fernández José M.
Published: September 2015

Polycationic amphiphilic cyclodextrins (paCDs) have been shown to behave as efficient non-viral gene carriers paralleling the efficacy of commercial vectors towards a variety of cell lines.
Evaluation of the aquatic toxic effect varied during the degradation of capecitabine under the environmental abiotic and biotic processes
Authors: Guo Ruixin , Zheng Fengzhu , Chen Jianqiu
Published: September 2015

Environmental risk due to the growing use of anticancer drugs has drawn wide public concern.
Nitrogen-doped carbon nanofibers with effectively encapsulated GeO2nanocrystals for highly reversible lithium storage
Authors: Mei Lin , Mao Minglei , Chou Shulei , Liu Huakun , Dou Shixue , Ng Dickon H. L. , Ma Jianmin
Published: September 2015

Germanium dioxide is a promising high-capacity anode material for lithium-ion batteries, but it usually exhibits poor cycling stability due to its large volume change during the lithiation/delithiation process.
A porous Co(OH)2 material derived from a MOF template and its superior energy storage performance for supercapacitors
Authors: Wang Zifeng , Liu Yushan , Gao Chengwei , Jiang Hao , Zhang Jianmin
Published: September 2015

A novel method was explored to synthesize porous Co(OH)2 using a Co-based metal–organic framework (MOF) as a template.
Hierarchically mesoporous carbon nanopetal based electrodes for flexible supercapacitors with super-long cyclic stability
Authors: Cherusseri Jayesh , Kar Kamal K.
Published: September 2015

Flexible supercapacitors manufactured with hierarchically mesoporous carbon nanopetal based electrodes exhibit high capacitance and power density with super-long cyclic stability.
Aggregation induced emission and mechanochromism in pyrenoimidazoles
Authors: Jadhav Thaksen , Dhokale Bhausaheb , Mobin Shaikh M. , Misra Rajneesh
Published: September 2015

Pyrene-based solid state emitters 3a and 3b were designed and synthesized by the Pd-catalyzed Suzuki cross-coupling reaction. Pyrenoimidazoles 3a and 3b exhibit strong AIE and reversible mechanochromic behavior with color contrast between blue and green.
Tuning the oxidation potential of 2-phenylpyridine-based iridium complexes to improve the performance of bluish and white OLEDs
Authors: Wang Yafei , Sun Ning , Curchod Basile F. E. , Male Louise , Ma Dongge , Fan Jiang , Liu Yu , Zhu Weiguo , Baranoff Etienne
Published: September 2015

Electron-donating substituents are used to fine-tune the redox properties of sky-blue cyclometalated iridium complexes and improve their electroluminescence performance.
Correction: The effect of device geometry and crystal orientation on the stress-dependent offset voltage of 3C–SiC(100) four terminal devices
Authors: Qamar Afzaal , Phan Hoang-Phuong , Han Jisheng , Tanner Philip , Dinh Toan , Wang Li , Dimitrijev Sima , Dao Dzung Viet
Published: September 2015

Correction for ‘The effect of device geometry and crystal orientation on the stress-dependent offset voltage of 3C–SiC(100) four terminal devices’ by Afzaal Qamar et al., J. Mater. Chem. C, 2015, 3, 8804–8809.
Correction: High thermoelectric performance of a defect in α-In2Se3-based solid solution upon substitution of Zn for In
Authors: Cui Jiaolin , Wang Li , Du Zhengliang , Ying Pengzhan , Deng Yuan
Published: September 2015

Correction for ‘High thermoelectric performance of a defect in α-In2Se3-based solid solution upon substitution of Zn for In’ by Jiaolin Cui et al., J. Mater. Chem. C, 2015, 3, 9069–9075.
Enhanced authentication for WLAN–EPS interworking systems
Authors: Bassoli R. , Marques H. , Rodriguez J. , Gruet C. , Tafazolli R.
Published: September 2015

Novel authentication procedures for interworking wireless local area networks and evolved packet system are proposed for the 3GPP TS 33.402 (released 12 September 2014) standard. The novel solutions mainly exploit public‐key fully homomorphic encryption schemes and one‐way functions. This not only mitigates potential security threats, but significantly reduces the authentication load of the standard, especially in the case of 3GPP‐IP access.
Unsupervised classification for hybrid polarimetric SAR data based on scattering mechanisms and Wishart classifier
Authors: Chen Shiqiang , Guo Shenglong , Li Yang , Hong Wen
Published: September 2015

An unsupervised classification algorithm utilising both polarimetric scattering mechanisms (PSMs) of hybrid‐polarity data and the Wishart classifier is proposed. The initial scattering categories of the proposed algorithm are derived from the roll‐invariant m–χ classification algorithm. Pixels with no clearly defined dominant PSM are excluded, and the resulting categories are expanded into a specified number of classes. These derived classes are taken as training samples of the Wishart classifier. The effectiveness of the proposed algorithm is validated with the dataset over San Francisco.
Compact microstrip tri‐band lowpass‐bandpass filter
Authors: Xu Jin
Published: September 2015

A compact microstrip tri‐band lowpass‐bandpass filter is described. Two different sets of λ/4 uniform‐impedance open stubs generate the desired transmission zeros (TZs) to divide a lowpass frequency response based on a radial stub loaded high‐impedance microstrip line into a tri‐band lowpass‐bandpass frequency response. A lowpass passband with a 3 dB cutoff frequency of 0.66 GHz, and two bandpass passbands centred at 1.57 and 2.45 GHz for global positioning system and wireless local area network applications are obtained in this design. The fabricated tri‐band lowpass‐bandpass filter occupies a compact circuit area of 0.065 λgc × 0.085 λgc. Seven TZs around the three passbands result in high band‐to‐band isolation, good passband selectivity and a wide upper stopband.
Characteristics of digitised millimetre‐wave metal reflectarray antennas
Authors: Yi Minwoo , Lee Woosang , So Joonho
Published: September 2015

Reflectarray antennas composed of rectangular grooves with a digitised phase‐shift element are designed for the millimetre‐wave region. The digitised metal antennas have been realised by quantising the phase shift of each rectangular groove. For 4 bit quantised antennas, the far‐field patterns are very similar to those of the non‐digitised case and especially show that the measured gain of the 2 bit reflectarray is only 1 dB lower than that of a non‐digitised reflectarray antenna. These results will contribute to saving manufacturing cost and time and the guidance of the phase shifter for an active metal reflectarray antenna for millimetre‐wave wireless networking or imaging systems.
Fault detection for offshore wind farm connected to onshore grid via voltage source converter‐high voltage direct current
Authors: Perveen Rehana , Kishor Nand , Mohanty Soumya R.
Published: September 2015

The fault study in offshore wind farm connected to onshore grid is carried out using empirical mode decomposition (EMD) which is a powerful technique for analysing linear, non‐linear, stationary and non‐stationary signals. The efficacy of the proposed approach is carried out by virtue of comparative assessment with other well‐established signal processing techniques: wavelet transform, Stockwell transform, hyperbolic Stockwell transform in the literature. The intrinsic mode functions (IMFs) are obtained using EMD for signals (normal and fault) retrieved at different sections. Hilbert transform is applied to each IMF in order to evaluate the magnitude and phase angle information used for analysing the signal. Both qualitative and quantitative analyses are carried out to demonstrate the effective detection of fault occurrence. The adopted approach accurately discriminates the occurrence of fault in AC/DC network section. The validation of the detection algorithm has been demonstrated through real‐time digital simulator studies. In addition, faulty sections are characterised adopting classification strategy using support vector machines.
Feature extraction and severity assessment of partial discharge under protrusion defect based on fuzzy comprehensive evaluation
Authors: Zeng Fuping , Dong Yulin , Tang Ju
Published: September 2015

Partial discharge (PD) is an early manifestation of insulation fault that occurs in electrical equipment, which holds rich feature information used to insulation assessment. In this study, step voltage method was applied to investigate the PD development process of typical protrusion defects in gas‐insulated switchgear. Nine features were extracted to represent the deterioration degree of internal insulation. Fuzzy C means clustering was applied to solve the state centres. PD severity was divided into four states based on the PD developing process, and the harmfulness of each state was illustrated. Finally, adaptive objective weight technology based on the theory of maximising deviation was adopted, and two‐level fuzzy comprehensive evaluation (TL‐FCE) model was established to address the problem of the weight allocation of different features on the evaluation result. The experimental test has been conducted to test the validity and effectiveness of the model. It is proved that TL‐FCE owns good performance to assess PD severity, and it is more suitable to handle fuzzy boundary problems than support vector machine.
Critical span identification model for dynamic thermal rating system placement
Authors: Teh Jiashen , Cotton Ian
Published: September 2015

Dynamic thermal rating (DTR) system is one of the efficient ways to increase transmission lines utilisation. Ideally, its application requires the deployment of sensors on each span of the transmission line. This is because a transmission line normally traverses a large geographical area and is affected by various weather conditions. Consequently, each span elongates differently and has different thermal ratings from one another. However, due to the large number of spans, it is uneconomical to place sensors on each span. Whilst doing that, it is also vital to ensure that the DTRs do not cause overrating in any spans to the point of causing ground clearance infringement. Among these spans, some appear to have lower thermal capacity due to its undesirable surrounding weather conditions and may also have smaller ground clearances. In this study, these spans are known as the “critical span”. This study proposed that by monitoring only these critical spans, the DTRs obtained can be safely applied to all other spans without the risk of ground clearance infringement. To do that, a novel critical span identification technique for the optimum placement of DTR sensors is presented in this paper.
Monitoring and identification of metal–oxide surge arrester conditions using multi‐layer support vector machine
Authors: Khodsuz Masume , Mirzaie Mohammad
Published: September 2015

Metal–oxide surge arresters (MOSAs) are essential equipments for power system protection and devices from lightning and switching transient overvoltages. Therefore, their operating condition and diagnosis are very important. In this study, a multi‐layer support vector machine (SVM) classifier has been used for MOSA conditions monitoring based on experimental tests. Three features are extracted based on the test results for determining surge arresters operating conditions including clean virgin, ultraviolet (UV) aged clean surface, surface contaminations after and before UV housing ageing, and degraded varistors along active column. Then, the multi‐layer SVM classifier is trained with the training samples, which are extracted by the above data processing. Finally, the five fault types of surge arresters are identified by this classifier. The test results show that the classifier has an excellent performance on training speed and reliability which confirm the high applicability of introduced features for correct diagnostic of surge arresters conditions.
Intramolecular structure and dynamics of mequinol and guaiacol in the gas phase: Rotationally resolved electronic spectra of their S1 states
Authors: Ruiz-Santoyo José Arturo , Rodríguez-Matus Marcela , Cabellos José Luis , Yi John T. , Pratt David W. , Schmitt Michael , Merino Gabriel , Álvarez-Valtierra Leonardo
Published: September 2015

The molecular structures of guaiacol (2-methoxyphenol) and mequinol (4-methoxyphenol) have been studied using high resolution electronic spectroscopy in a molecular beam and contrasted with ab initio computations. Mequinol exhibits two low frequency bands that have been assigned to electronic origins of two possible conformers of the molecule, trans and cis. Guaiacol also shows low frequency bands, but in this case, the bands have been assigned to the electronic origin and vibrational modes of a single conformer of the isolated molecule. A detailed study of these bands indicates that guaiacol has a vibrationally averaged planar structure in the ground state, but it is distorted along both in-plane and out-of-plane coordinates in the first electronically excited state. An intramolecular hydrogen bond involving the adjacent   –OH and   –OCH3 groups plays a major role in these dynamics.
Determination of contact maps in proteins: A combination of structural and chemical approaches
Authors: Wołek Karol , Gómez-Sicilia Àngel , Cieplak Marek
Published: September 2015

Contact map selection is a crucial step in structure-based molecular dynamics modelling of proteins. The map can be determined in many different ways. We focus on the methods in which residues are represented as clusters of effective spheres. One contact map, denoted as overlap (OV), is based on the overlap of such spheres. Another contact map, named Contacts of Structural Units (CSU), involves the geometry in a different way and, in addition, brings chemical considerations into account. We develop a variant of the CSU approach in which we also incorporate Coulombic effects such as formation of the ionic bridges and destabilization of possible links through repulsion. In this way, the most essential and well defined contacts are identified. The resulting residue-residue contact map, dubbed repulsive CSU (rCSU), is more sound in its physico-chemical justification than CSU. It also provides a clear prescription for validity of an inter-residual contact: the number of attractive atomic contacts should be larger than the number of repulsive ones — a feature that is not present in CSU. However, both of these maps do not correlate well with the experimental data on protein stretching. Thus, we propose to use rCSU together with the OV map. We find that the combined map, denoted as OV+rCSU, performs better than OV. In most situations, OV and OV+rCSU yield comparable folding properties but for some proteins rCSU provides contacts which improve folding in a substantial way. We discuss the likely residue-specificity of the rCSU contacts. Finally, we make comparisons to the recently proposed shadow contact map, which is derived from different principles.
Isothermal tuning of magnetic coercivity in NiFe/NiO/[Co/Pt] heterostructures with orthogonal easy axes
Authors: Baruth A.
Published: September 2015

Heterostructures of NiFe/NiO/[Co/Pt] with mutually orthogonal easy axes allow for isothermal tuning of the magnetic coercivity at room temperature with no associated shift in the hysteresis loop along the applied field axis. This is in contrast to what is typically seen in exchange biased heterostructures. The NiFe coercivity is enhanced from 14.5 to 105 Oe through the application of moderate dc magnetic fields of <3 kOe. This enhancement is completely reset with the application of a similarly sized dc magnetic field perpendicular to the film. The pinning of the antiferromagnetic NiO interlayer (i.e., blocking temperature, which is expected to be well below 50 K at this thickness in the absence of adjacent magnetic layers) is greatly enhanced and influenced by the in-plane magnetization of both the NiFe and [Co/Pt]. In addition, these heterostructures show unique high and low-field training effects due to alignment of [Co/Pt] stripe domains. This dynamic, yet predictable, behavior where the coercivity is isothermally tuned without any permanent structural/chemical modifications has potential uses in advanced magnetic logic/storage, as well as tuning the interfacial coupling in spintronic applications.
Response to “Comment on ‘Diffusion of n-type dopants in germanium’ ” [Appl. Phys. Rev. 2, 036101 (2015)]
Authors: Bracht H. , Südkamp T. , Radek M. , Chroneos A.
Published: September 2015

In this reply to the comment of Cowern et al., we demonstrate on the basis of full numerical simulations of radiation enhanced dopant diffusion via the kick-out mechanism that the g/λ analysis fails to consistently describe boron (B) diffusion in germanium (Ge) under irradiation. Cowern et al. missed to perform a consistency check with results for the diffusivity DI of Ge interstitials (I) determined from Ge self-diffusion under irradiation. Data deduced for DI from the exponential B profile reported by Cowern et al. deviate several orders of magnitude from the self-diffusion study. This clearly disproves the validity of the kick-out mechanism to control radiation enhanced B diffusion in Ge. Exponential B profiles like those established in Ge under irradiation are also reported for silicon by Venezia et al. [Phys. Rev. B 69, 125215 (2004)]. The characteristic shape is not described by the kick-out mechanism but rather explained qualitatively by the complex formation and dissolution of defect clusters. Modeling of B diffusion in Ge under irradiation performed by Schneider et al. [Phys. Rev. B 87, 115202 (2013)] is fully consistent with self-diffusion under irradiation. This constraint led us to conclude that the characteristic B profiles are additionally affected by the formation of immobile B clusters. Although a direct microscopic proof of B cluster formation is still lacking, the report of Venezia et al. on B clustering in Si during irradiation with similar exponential B profiles also supports our interpretation of B diffusion in Ge under irradiation.
Dual control of ferromagnetic resonance frequency in multiferroic heterostructures by oblique deposition and electrical field
Authors: Phuoc Nguyen N. , Ong C. K.
Published: September 2015

By using oblique deposition technique to fabricate FeCo/MnIr/[Pb(Mg1/3Nb2/3)O3]0.68-[PbTiO3]0.32 (011) multiferroic heterostructures, we experimentally demonstrate that it is feasible to dually control the ferromagnetic resonance frequency by changing an oblique deposition angle and an applied electrical field. In particular, by changing the oblique angle, the resonance frequency of the samples in unpoled state can be fixed from 2.39 GHz to 9 GHz. Upon the application of the electrical field varied from 0 kV/cm to 6 kV/cm, the resonance frequency of each sample shows different tunability range depending on the oblique angle and it can be tailored beyond 10 GHz. The result can be interpreted in terms of the enhancement of the magnetic anisotropy arising from the inverse magnetostriction effect. Our demonstration suggests a great implication for tunable microwave applications with ultra-wide band requirement.
A closed-loop pump-driven wire-guided flow jet for ultrafast spectroscopy of liquid samples
Authors: Picchiotti Alessandra , Prokhorenko Valentyn I. , Miller R. J. Dwayne
Published: September 2015

We describe the design and provide the results of the full characterization of a closed-loop pump-driven wire-guided flow jet system. The jet has excellent optical quality with a wide range of liquids spanning from alcohol to water based solutions, including phosphate buffers used for biological samples. The thickness of the jet film varies depending on the flow rate between 90 μm and 370 μm. The liquid film is very stable, and its thickness varies only by 0.76% under optimal conditions. Measured transmitted signal reveals a long term optical stability (hours) with a RMS of 0.8%, less than the overall noise of the spectroscopy setup used in our experiments. The closed loop nature of the overall jet design has been optimized for the study of precious biological samples, in limited volumes, to remove window contributions from spectroscopic observables. This feature is particularly important for femtosecond studies in the UV range.
Generation of localized strain in a thin film piezoelectric to control individual magnetoelectric heterostructures
Authors: Cui Jizhai , Liang Cheng-Yen , Paisley Elizabeth A. , Sepulveda Abdon , Ihlefeld Jon F. , Carman Gregory P. , Lynch Christopher S.
Published: September 2015

Experimental results demonstrate the ability of a surface electrode pattern to produce sufficient in-plane strain in a PbZr0.52Ti0.48O3 (PZT) thin film clamped by a Si substrate to control magnetism in a 1000 nm diameter Ni ring. The electrode pattern and the Ni ring/PZT thin film heterostructure were designed using a finite element based micromagnetics code. The magnetoelectric heterostructures were fabricated on the PZT film using e-beam lithography and characterized using magnetic force microscopy. Application of voltage to the electrodes moved one of the “onion” state domain walls. This method enables the development of complex architectures incorporating strain-mediated multiferroic devices.
Coupled mechanical-oxidation modeling during silicon thermal oxidation process
Authors: Zhang Yang , Zhang Xian-Cheng , Tu Shan-Tung
Published: September 2015

This work provided an analytical model to solve the coupled mechanical-oxidation problem during the silicon thermal oxidation process. The silicon thermal oxidation behavior under two different mechanical load conditions, i.e., constant strain and uniaxial stress, were considered. The variations of oxide stress and scale thickness along with oxidation time were predicted. During modeling, all the effects of stress accumulation due to growth strain, stress relaxation due to viscous flow and the external load on the scale growth rate were taken into consideration. Results showed that the existence of external loads had an obvious influence on the oxide stress and scale thickness. Generally, tensile stress or strain accelerated the oxidant diffusion process. However, the reaction rate at the Si/SiO2 interface was retarded under uniaxial stress, which was not found in the case of constant strain load.
Thermal conductivity of granular porous media: A pore scale modeling approach
Authors: Askari R. , Taheri S. , Hejazi S. H.
Published: September 2015

Pore scale modeling method has been widely used in the petrophysical studies to estimate macroscopic properties (e.g. porosity, permeability, and electrical resistivity) of porous media with respect to their micro structures. Although there is a sumptuous literature about the application of the method to study flow in porous media, there are fewer studies regarding its application to thermal conduction characterization, and the estimation of effective thermal conductivity, which is a salient parameter in many engineering surveys (e.g. geothermal resources and heavy oil recovery). By considering thermal contact resistance, we demonstrate the robustness of the method for predicting the effective thermal conductivity. According to our results obtained from Utah oil sand samples simulations, the simulation of thermal contact resistance is pivotal to grant reliable estimates of effective thermal conductivity. Our estimated effective thermal conductivities exhibit a better compatibility with the experimental data in companion with some famous experimental and analytical equations for the calculation of the effective thermal conductivity. In addition, we reconstruct a porous medium for an Alberta oil sand sample. By increasing roughness, we observe the effect of thermal contact resistance in the decrease of the effective thermal conductivity. However, the roughness effect becomes more noticeable when there is a higher thermal conductivity of solid to fluid ratio. Moreover, by considering the thermal resistance in porous media with different grains sizes, we find that the effective thermal conductivity augments with increased grain size. Our observation is in a reasonable accordance with experimental results. This demonstrates the usefulness of our modeling approach for further computational studies of heat transfer in porous media.
External field effects on aging phenomenon of acceptor-doped BaTiO3 ceramics
Authors: Guo Y. Y. , Liu J.-M. , Guo Y. F. , Wei T. , Guo Y. J. , Zhang N.
Published: September 2015

Our experiments on ferroelectric aging phenomena of a series of acceptor-doped BaTiO3 ceramics demonstrate that after well-aging, all samples show a similar double hysteresis loop under smaller applied electric field, regardless of ionic radius or ionic valence of the acceptor. However, with increasing the applied electric field, the completely constricted loops gradually start to open, indicating the aging effect becomes weak under larger electric field. The unified microscopic mechanism responsible for the similar aging behavior in different acceptor-doped BaTiO3 ceramics may be that the larger field is considered to kinetically facilitate a part of oxygen vacancies short-range hopping. As a result, the defect dipole field provided by oxygen vacancies and the associated defect dipoles frozen in the original states decreases, thus contributing to the weaker aging effect.
Allyl Sulfides: Reactive Substrates for Olefin Metathesis
Authors: Chalker Justin M.
Published: August 2015

Allyl sulfides have gained traction in recent years as promoters for olefin metathesis. The high reactivity of allyl sulfides in olefin metathesis is remarkable, given that many sulfur-containing substrates are incompatible with ruthenium-based olefin metathesis catalysts. In stark contrast, allyl sulfides actually enhance the rate of metathesis in comparison with other alkenes, when matched with a suitable catalyst. This review examines how the high reactivity of allyl sulfides in olefin metathesis has been harnessed in diverse areas of synthesis. In the cases examined, allyl sulfides have been explicitly incorporated into substrates to promote olefin metathesis. Recent insights into catalyst considerations, applications in chemical and biochemical synthesis, and future opportunities are discussed.
Natural history and conservation biology of the tooth-billed pigeon (Didunculus strigirostris): a review
Authors: Collar N. J.
Published: August 2015

Fears that the evolutionarily distinctive tooth-billed pigeon (Didunculus strigirostris), endemic to Samoa, is close to extinction have prompted initiatives based on incomplete information. The species was widely distributed in forests on Upolu and Savaii from sea level to indeterminate elevations linked to its main food trees, Dysoxylum maota and D. samoense. Its bill is adapted to feed on Dysoxylum fruits although first-year birds apparently cannot do so. It occupies the middle strata of forest but sometimes forages discreetly on the ground. Breeding activity spans March to November, mostly April to September. One nest was in a Ficus at 25 m; other reports suggest similar locations. Birds sing sporadically throughout this period, but their reclusive behaviour, general silence and immobility render detection, and hence population density assessment, difficult. Many, but not all, nineteenth-century writers thought the species was becoming extinct, their reports conceivably reflecting real fluctuations in numbers. From the 1980s, however, evidence mounted that hunting and habitat destruction were seriously impacting the estimated 3200 birds on Upolu and 4800 on Savaii. Two cyclones in 1990 and 1991 destroyed much habitat; by 2000 only some 2500 birds were estimated to survive, and by 2006, when a recovery plan was issued, only 500; the most recent searches suggest fewer than 50 on each main island. Apart from hunting and habitat loss, predation by introduced rats and perhaps cats may be a serious limiting factor in the present century. Preservation and restoration of forests, elimination of hunting and control of predators are all needed, backed by a program of targeted research to establish the distribution of key Dysoxylum food plants and hence elevation limits, to identify any remaining forest areas with high density of Dysoxylum, and to study in detail the ecology and behaviour of birds in any and all surviving populations.
MavN is a
Legionella pneumophila
vacuole-associated protein required for efficient iron acquisition during intracellular growth
Authors: Isaac Dervla T. , Laguna Rita K. , Valtz Nicole , Isberg Ralph R.
Published: September 2015

Significance

Limiting access of intracellular iron to intracellular microbes is a critical arm of the nutritional immune response. Little is known about the mechanisms used by intravacuolar pathogens to overcome this attempted starvation. We show here that
Legionella pneumophila
employs its major virulence-associated secretion system to deliver a unique transmembrane protein into host cells during infection. Utilizing microscopic, biochemical, and transcriptional analysis of intracellular bacteria, we demonstrate that the MavN protein integrates into the host-derived vacuolar membrane and facilitates transport of essential iron into the lumen of the vacuole to promote bacterial growth. These findings shed light on what is likely to be a myriad of strategies used by bacteria to overcome potent host nutrient restrictions.