bluuebunny/crossref_metadata_2025 huggingface dataset:
Retrieving orbital angular momentum distribution of light with plasmonic vortex lens
Authors: Zhou Hailong , Dong Jianji , Zhang Jihua , Zhang Xinliang
Published: June 2016

We utilize a plasmonic vortex lens (PVL) to retrieve the orbital angular momentum (OAM) distribution of light. The OAM modes are coupled to the surface plasmon polaritons (SPPs) in the form of various Bessel functions respectively. By decomposing the interference pattern of SPPs into these Bessel functions, we can retrieve the relative amplitude and the relative phase of input OAM modes simultaneously. Our scheme shows advantage in integration and can measure hybrid OAM states by one measurement.
Purifying selection shapes the coincident SNP distribution of primate coding sequences
Authors: Chen Chia-Ying , Hung Li-Yuan , Wu Chan-Shuo , Chuang Trees-Juen
Published: June 2016

Genome-wide analysis has observed an excess of coincident single nucleotide polymorphisms (coSNPs) at human-chimpanzee orthologous positions and suggested that this is due to cryptic variation in the mutation rate. While this phenomenon primarily corresponds with non-coding coSNPs, the situation in coding sequences remains unclear. Here we calculate the observed-to-expected ratio of coSNPs (coSNPO/E) to estimate the prevalence of human-chimpanzee coSNPs and show that the excess of coSNPs is also present in coding regions. Intriguingly, coSNPO/E is much higher at zero-fold than at nonzero-fold degenerate sites; such a difference is due to an elevation of coSNPO/E at zero-fold degenerate sites, rather than a reduction at nonzero-fold degenerate ones. These trends are independent of chimpanzee subpopulation, population size, or sequencing techniques; and hold in broad generality across primates. We find that this discrepancy cannot fully explained by sequence contexts, shared ancestral polymorphisms, SNP density and recombination rate and that coSNPO/E in coding sequences is significantly influenced by purifying selection. We also show that selection and mutation rate affect coSNPO/E independently and coSNPs tend to be less damaging and more correlated with human diseases than non-coSNPs. These suggest that coSNPs may represent a “signature” during primate protein evolution.
Nutrient shortage triggers the hexosamine biosynthetic pathway via the GCN2-ATF4 signalling pathway
Authors: Chaveroux Cédric , Sarcinelli Carmen , Barbet Virginie , Belfeki Sofiane , Barthelaix Audrey , Ferraro-Peyret Carole , Lebecque Serge , Renno Toufic , Bruhat Alain , Fafournoux Pierre , Manié Serge N.
Published: June 2016

The hexosamine biosynthetic pathway (HBP) is a nutrient-sensing metabolic pathway that produces the activated amino sugar UDP-N-acetylglucosamine, a critical substrate for protein glycosylation. Despite its biological significance, little is known about the regulation of HBP flux during nutrient limitation. Here, we report that amino acid or glucose shortage increase GFAT1 production, the first and rate-limiting enzyme of the HBP. GFAT1 is a transcriptional target of the activating transcription factor 4 (ATF4) induced by the GCN2-eIF2α signalling pathway. The increased production of GFAT1 stimulates HBP flux and results in an increase in O-linked β-N-acetylglucosamine protein modifications. Taken together, these findings demonstrate that ATF4 provides a link between nutritional stress and the HBP for the regulation of the O-GlcNAcylation-dependent cellular signalling.
Using metabarcoding to reveal and quantify plant-pollinator interactions
Authors: Pornon André , Escaravage Nathalie , Burrus Monique , Holota Hélène , Khimoun Aurélie , Mariette Jérome , Pellizzari Charlène , Iribar Amaia , Etienne Roselyne , Taberlet Pierre , Vidal Marie , Winterton Peter , Zinger Lucie , Andalo Christophe
Published: June 2016

Given the ongoing decline of both pollinators and plants, it is crucial to implement effective methods to describe complex pollination networks across time and space in a comprehensive and high-throughput way. Here we tested if metabarcoding may circumvent the limits of conventional methodologies in detecting and quantifying plant-pollinator interactions. Metabarcoding experiments on pollen DNA mixtures described a positive relationship between the amounts of DNA from focal species and the number oftrnLand ITS1 sequences yielded. The study of pollen loads of insects captured in plant communities revealed that as compared to the observation of visits, metabarcoding revealed 2.5 times more plant species involved in plant-pollinator interactions. We further observed a tight positive relationship between the pollen-carrying capacities of insect taxa and the number oftrnLand ITS1 sequences. The number of visits received per plant species also positively correlated to the number of their ITS1 andtrnLsequences in insect pollen loads. By revealing interactions hard to observe otherwise, metabarcoding significantly enlarges the spatiotemporal observation window of pollination interactions. By providing new qualitative and quantitative information, metabarcoding holds great promise for investigating diverse facets of interactions and will provide a new perception of pollination networks as a whole.
Pro-apoptotic Bax molecules densely populate the edges of membrane pores
Authors: Kuwana Tomomi , Olson Norman H. , Kiosses William B. , Peters Bjoern , Newmeyer Donald D.
Published: June 2016

How the pro-apoptotic Bax protein permeabilizes the mitochondrial outer membrane is not fully understood. Previously, using cryo-electron microscopy (cryo-EM), we showed that activated Bax forms large, growing pores. Whether formed in liposomes or in mitochondrial outer membranes, Bax-induced pores exhibit the same morphology, with negative curvature flanking the edges and with no visible protein structure protruding from the membranes. Here we used cryo-EM to show that gold-labeled Bax molecules, after activation by Bid, became localized strictly at pore edges. This argues that Bax acts at short range to deform the membrane. Also, Bax molecules populated the walls of both small and large pores at the same density, implying that Bax is continuously recruited to the pores as they widen. Moreover, because all Bax molecules became oligomerized after membrane insertion, we infer that Bax oligomers are present at pore edges. We suggest that oligomerization may promote pore enlargement.
Mutation of the Traj18 gene segment using TALENs to generate Natural Killer T cell deficient mice
Authors: Zhang Jingjing , Bedel Romain , Krovi S. Harsha , Tuttle Kathryn D. , Zhang Bicheng , Gross James , Gapin Laurent , Matsuda Jennifer L.
Published: June 2016

Invariant Natural Killer T (iNKT) cells are a unique subset of T lymphocytes that have been implicated in both promoting and suppressing a multitude of immune responses. In mice, iNKT cells express T cell antigen receptors (TCRs) comprising a unique TCRα rearrangement between the Trav11 and Traj18 gene segments. When paired with certain Trbv TCRβ chains, these TCRs recognize lipid antigens presented by the major histocompatibility complex (MHC) class I-like molecule, CD1d. Until recently, the sole model of iNKT deficiency targeted the Jα18, which is absolutely required to form the TCR with the appropriate antigenic specificity. However, these mice were demonstrated to have a large reduction in TCR repertoire diversity, which could confound results arising from studies using these mice. Here, we have created a new NKT-deficient mouse strain using transcription activator-like effector nuclease (TALEN) technology to only disrupt the expression of Jα18, leaving the remaining Jα repertoire unperturbed. We confirm that these mice lack iNKT cells and do not respond to lipid antigen stimulation while the development of conventional T cells, regulatory T cells, and type Ib NKT cells is normal. This new mouse strain will serve as a new model of iNKT cell deficiency to facilitate our understanding of iNKT biology.
Unsaturation in binuclear heterometallic carbonyls: the cyclopentadienyliron manganese carbonyl CpFeMn(CO)nsystem as a hybrid of the Cp2Fe2(CO)nand Mn2(CO)nsystems
Authors: Feng Xiuli , Li Nan , Lv Liqiang , King R. Bruce
Published: June 2016

The structures and energetics of the CpFeMn(CO)n(n= 7, 6, 5) have been examined by density functional theory.
Multi-scale magnetic nanoparticle based optomagnetic bioassay for sensitive DNA and bacteria detection
Authors: Tian Bo , Zardán Gómez de la Torre Teresa , Donolato Marco , Hansen Mikkel Fougt , Svedlindh Peter , Strömberg Mattias
Published: June 2016

An optomagnetic bioassay is optimized by means of extending the linear range in the presence of larger nanoparticles.
Child safety: a validated GC-MS method to determine formamide in EVA foam mats
Authors: Wollinger W. , Monteiro T. M. , Campos E. G. , do Rego E. C. P. , da Cunha V. S.
Published: June 2016

A GC-MS method was developed to analyze residual formamide in EVA foam puzzle mats and products commercialized in Brazil were evaluated.
Silicone-based tough hydrogels with high resilience, fast self-recovery, and self-healing properties
Authors: Si Liqi , Zheng Xiaowen , Nie Jun , Yin Ruixue , Hua Yujie , Zhu Xiaoqun
Published: June 2016

A dual-component polymer hydrogel was prepared by one-pot, tandem polymerization. The concentration of monomer could be tuned freely due to the good water solubility of both monomers. The prepared hydrogels exhibited toughness, high resilience, fast self-recovery, and self-healing properties.
Catalytic dehydrocoupling of amine-boranes and amines into diaminoboranes: isolation of a Pt(ii), Shimoi-type, η1-BH complex
Authors: Roselló-Merino Marta , Rama Raquel J. , Díez Josefina , Conejero Salvador
Published: June 2016

The platinum complex [Pt(ItBu′)(ItBu)][BArF] is a very efficient catalyst in the synthesis of diaminoboranes through dehydrocoupling of amine-boranes and amines.
An alternative synthetic approach for macro–meso–microporous metal–organic frameworks via a “domain growth” mechanism
Authors: Zhan Guowu , Zeng Hua Chun
Published: June 2016

A nanoscale “domain growth” mechanism was proposed based on experimental facts to describe the formation process of macro–meso–microporous HKUST-1 with 3-dimensional networks.
Fluorescent zinc and copper complexes for detection of adrafinil in paper-based microfluidic devices
Authors: Caglayan Mehmet Gokhan , Sheykhi Sara , Mosca Lorenzo , Anzenbacher Pavel
Published: June 2016

Zn(ii) and Cu(ii) complexes are used in the recognition and sensing of adrafinil through an easy-to-detect fluorescence response.
Highly fluorescent extended 2-(2′-hydroxyphenyl)benzazole dyes: synthesis, optical properties and first-principle calculations
Authors: Raoui Mohamed , Massue Julien , Azarias Cloé , Jacquemin Denis , Ulrich Gilles
Published: June 2016

Restoration of ESIPT upon protonation was demonstrated in an extended-hydroxybenzothiazole derivative in which it was fully inhibited in the neutral state.
Chirality of self-assembled achiral porphyrins induced by chiral Zn(ii) Schiff-base complexes and maintained after spontaneous dissociation of the templates: a new case of chiral memory
Authors: Gaeta Massimiliano , Oliveri Ivan Pietro , Fragalà Maria Elena , Failla Salvatore , D'Urso Alessandro , Di Bella Santo , Purrello Roberto
Published: June 2016

We report a case of chiral memory in porphyrin aggregates templated by chiral Zn(ii) Schiff-base complexes which readily dissociate in aqueous solution.
Complexes trans-Pt(BODIPY)X(PEt3)2: excitation energy-dependent fluorescence and phosphorescence emissions, oxygen sensing and photocatalysis
Authors: Irmler Peter , Winter Rainer F.
Published: June 2016

Complexes trans-Pt(BODIPY)X(PEt3)2 exhibit dual fluorescence and phosphorescence emissions, whose intensities are modulated by the anionic ligand X− and the excitation wavelengths. They constitute efficient single-component 3O2 sensors and photocatalysts for aereal photooxidations with quantum yields near unity.
Reduction and persulfate oxidation of nitro explosives in contaminated soils using Fe-bearing materials
Authors: Oh Seok-Young , Yoon Hyun-Su , Jeong Tae-Yong , Kim Sang Don , Kim Dong-Wook
Published: June 2016

The oxidative and reductive transformation of nitro explosives in contaminated soils with Fe-bearing materials and persulfate (S2O82−) was examined via batch experiments.
Crystal structures, topological analysis and luminescence properties of three coordination polymers based on a semi-rigid ligand and N-donor ligand linkers
Authors: Liu Xiaobin , Xiao Zhenyu , Huang Ao , Wang Wen , Zhang Liangliang , Wang Rongming , Sun Daofeng
Published: June 2016

Three new mixed-ligand coordination polymers have been synthesized based on 3,3′-(anthracene-9,10-diyl)diacrylate acid and different N-donor ligands. Complex 2 displays rapid and selective sensing of Fe3+.
Reactivity and selectivity of the reaction of O,O-diethyl 2,4-dinitrophenyl phosphate and thionophosphate with thiols of low molecular weight
Authors: Santos J. G. , Aliaga M. E. , Alarcón K. , Torres A. , Céspedes D. , Pavez P.
Published: June 2016

A kinetics control product by sulfhydryl attack of thiols was observed in the reactions of both triesters with Cys and Hcys, followed by an intramolecular amine attack leading to a thermodynamic control product.
Magnetic relaxations in four-coordinate Dy(iii) complexes: effects of anionic surroundings and short Dy–O bonds
Authors: Yu Ke-Xin , Ding You-Song , Han Tian , Leng Ji-Dong , Zheng Yan-Zhen
Published: June 2016

Two four-coordinate Dy(iii) mononuclear complexes show disparate magnetic relaxation behaviour due to the differentiated Dy–O/N bond lengths.
Effect of preparation method on performance of Cu–Fe/SiO2catalysts for higher alcohols synthesis from syngas
Authors: Sun Chao , Mao Dongsen , Han Lupeng , Yu Jun
Published: June 2016

Cu–Fe/SiO2catalyst prepared by ultrasound-assisted impregnation exhibits higher CO conversion and alcohols yield than those by the other methods.
Iron–copper bimetallic nanoparticles supported on hollow mesoporous silica spheres: the effect of Fe/Cu ratio on heterogeneous Fenton degradation of a dye
Authors: Wang Jing , Liu Chao , Hussain Ijaz , Li Cheng , Li Jiansheng , Sun Xiuyun , Shen Jinyou , Han Weiqing , Wang Lianjun
Published: June 2016

A series of iron–copper bimetallic nanoparticles supported on hollow mesoporous silica spheres with different Fe/Cu ratios were prepared using a simple post-impregnation and sodium borohydride reduction strategy.
A reactive blend of electroactive polymers exhibiting synergistic effects on self-healing and anticorrosion properties
Authors: Chuo Tsai-Wei , Yeh Jui-Ming , Liu Ying-Ling
Published: June 2016

The first example of electrically-induced self-healing anticorrosion materials shows synergistic effects on anticorrosion efficiency and self-healing property.
Unusual blue-shifted acid-responsive photoluminescence behavior in 6-amino-8-cyanobenzo[1,2-b]indolizines
Authors: Outlaw Victor K. , Zhou Jiawang , Bragg Arthur E. , Townsend Craig A.
Published: June 2016

6-Amino-8-cyanobenzo[1,2-b]indolizines, a new class of photoluminescent materials, exhibit reversible pH-dependent optical properties characterized by an uncommon and dramatic blue shift in fluorescence emission when protonated.
The efficient and selective catalytic oxidation of para-substituted cinnamic acid derivatives by the cytochrome P450 monooxygenase, CYP199A4
Authors: Chao Rebecca R. , De Voss James J. , Bell Stephen G.
Published: June 2016

The cytochrome P450 enzyme, CYP199A4 oxidisedparasubstituted alkyloxy- and alkyl-cinnamic acids, with high product formation activity.
A novel approach to formulate high flux multifunctional ultrafiltration membranes from photocatalytic titania composite precursors on multi-channel tubular substrates
Authors: Manjumol K. A. , Sankar S. , Nair Balagopal N. , Midhun M. , Mohamed Peer A. , Warrier K. G. K.
Published: June 2016

Anatase rich titanium dioxide ultrafiltration membranes with high filtration rates have been successfully developed on multi-channel tubular alumina substrates via aqueous sol–gel method from titania–alumina composite precursors.
Enhancement of ion dynamics in organic ionic plastic crystal/PVDF composite electrolytes prepared by co-electrospinning
Authors: Wang Xiaoen , Zhu Haijin , Greene George W. , Li Jiaye , Iranipour Nahid , Garnier Célia , Fang Jian , Armand Michel , Forsyth Maria , Pringle Jennifer M. , Howlett Patrick C.
Published: June 2016

Organic ionic plastic crystal (OIPC) modified poly(vinylidene difluoride) (PVDF) composite fiber membrane with enhanced ion dynamics and almost pure β-PVDF are demonstrated.
Patterns of Gesture Use in Adolescents With Autism Spectrum Disorder
Authors: Braddock Barbara A. , Gabany Christina , Shah Meera , Armbrecht Eric S. , Twyman Kimberly A.
Published: June 2016

Purpose

The purpose of this study was to examine patterns of spontaneous gesture use in a sample of adolescents with autism spectrum disorder (ASD).

Method

Thirty-five adolescents with ASD ages 11 to 16 years participated (mean age = 13.51 years; 29 boys, 6 girls). Participants' spontaneous speech and gestures produced during a narrative task were later coded from videotape. Parents were also asked to complete questionnaires to quantify adolescents' general communication ability and autism severity.

Results

No significant subgroup differences were apparent between adolescents who did not gesture versus those who produced at least 1 gesture in general communication ability and autism severity. Subanalyses including only adolescents who produced gesture indicated a statistically significant negative association between gesture rate and general communication ability, specifically speech and syntax subscale scores. Adolescents who gestured produced higher proportions of iconic gestures and used gesture mostly to add information to speech.

Conclusions

The findings relate spontaneous gesture use to underlying strengths and weaknesses in adolescents' speech and syntactical language development. More research examining cospeech gesture in fluent speakers with ASD is needed.
Research on a current commutation drive circuit for hybrid dc circuit breaker and its optimisation design
Authors: Wen Weijie , Huang Yulong , Cheng Tiehan , Gao Shutong , Chen Zhengyu , Zhang Xiangyu , Yu Zhanqing , Zeng Rong , Liu Weidong
Published: June 2016

Hybrid direct current circuit breakers (DCCBs) have great prospects for the isolation of dc faults in multi‐terminal dc grids. Current commutation from the mechanical switch branch to the static DCCB branch is the precondition to interrupt fault currents successfully for the hybrid DCCBs. A current commutation drive circuit (CCDC) is presented in this study, and it has features of low cost, low operating losses and free maintenance. Experiments have been carried out on a unidirectional 44 kV hybrid DCCB prototype with CCDC. The results show the current of 3.4 kA can be commutated by CCDC within 130 μs, and be interrupted successfully within 2 ms. For a bidirectional 80 kV hybrid DCCB cell, the effectiveness of CCDC is validated with simulations carried out in PACAD. Then, an index is defined to represent the current commutation capability of CCDC and a mathematical model for CCDC is established to calculate the index. To reduce the cost of CCDC with certain current commutation capability, an optimisation method based on genetic algorithm is proposed in this study. According to the optimisation results of CCDC suitable for bidirectional 80 kV hybrid DCCB cell, the cost of CCDC has been reduced by optimisation.
Charging demand for electric vehicle based on stochastic analysis of trip chain
Authors: Shun Tao , Kunyu Liao , Xiangning Xiao , Jianfeng Wen , Yang Yang , Jian Zhang
Published: June 2016

With its popularisation, electric vehicle (EV) has been part of the important load of smart grid. The analysis on charging demands of EVs is the basis of the study of influences on power grid and charging infrastructures planning. Charging demand calculation is based on the precise analysis on the driving law of users. This study proposes a method based on the stochastic simulation of trip chain to solve the existing problem. First, the concept and characteristic variables (trip start time, driving time, parking duration, driving distance and trip purpose) of trip chain are introduced. Second, the probability distribution models of these variables are established considering their correlative relationships. Third, using Monte Carlo method, the complete trip chains are simulated, and then the spatial–temporal distributions of charging demands are calculated. Finally, based on the National household trip survey data, and according to the proposed method, charging demands in different areas are studied. The results show that the proposed method can accurately simulate the driving law of users and reflect spatial–temporal distribution characteristics of charging demands, and different charging scenarios will lead to different forms of charging demand distribution, which will exert different impacts on power system.
Improved voltage shift islanding detection method for multi‐inverter grid‐connected photovoltaic systems
Authors: Liu Sijia , Zhuang Shengxian , Xu Quan , Xiao Jian
Published: June 2016

This study presents an improved voltage shift islanding detection method with the new control mode. The proposed method adopts the modulation index shift scheme based on the pulse‐width modulation control principle, which can promote the detection performance in the multi‐inverter grid‐connected photovoltaic (PV) systems, compared with the conventional voltage positive feedback (VPF) method. The superposition algorithm of the proposed method can make the rapid reduction of voltage magnitude at the point of common coupling during the islanding condition, and minimise the non‐detection zone. Through the self‐varying positive feedback gain, the synchronisation of voltage shift rates from multiple PV inverters can be effectively improved under the varying active power conditions. According to the characteristic of maximum power point tracking control, the gain will be automatically changed along with the variable PV voltage. The advantage of the proposed method is analysed by the simulation results in comparison with the conventional VPF method. Moreover, the experimental results are provided to verify the effectiveness of the proposed method.
Successive power flows with adaptive step‐length increments for fast approximation of the maximum loading point
Authors: Yang Xiaoyu , Zhou Xiaoxin , Li Yalou , An Ning , Li Fang
Published: June 2016

This study is concerned with the problem of computing the maximum loading point (MLP) in large‐scale power systems. A modified asymptotic numerical method (ANM) with λ‐parameterisation is used to fast approximate the MLP, which needs to solve a successive of power flows with adaptive load and generation increments. The ANM with Newton corrections is used to deal with the problem of reactive limits violations. The saddle‐node bifurcation is identified by the accumulation of small step‐lengths. The proposed algorithm has been tested on the IEEE‐300, 9241‐bus and a real 35,000‐bus power system in China. Some comparisons with other algorithms have been performed. Numerical results reveal that a lower number of the Jacobian matrix factorisations are needed with the proposed method, which significantly reduces the computational costs.
Application of high‐order Levenberg–Marquardt method for solving the power flow problem in the ill‐conditioned systems
Authors: Pourbagher Rohallah , Derakhshandeh Sayed Yaser
Published: June 2016

In an ill‐conditioned power system, the Jacobian matrix is singular or near singular and solving the power flow equations by the traditional methods such as Newton method may lead to divergence. In this paper, we have applied a high‐order Levenberg–Marquardt approach for solving the power flow problems in the ill‐conditioned power systems. High reliability and high speed are the main characteristics of the proposed method. Using the controlling parameters of this method (σ and μ) can decrease the number of iterations and the computation time in solving the power flow problem of the ill‐conditioned power systems. The proposed formulations and algorithm are tested on the 11‐bus, 57‐bus, 118‐bus and 2383‐bus ill‐conditioned test systems. The simulation results show that the proposed method can significantly reduce the computation time and the number of iterations.
Compact paper‐substrate rat‐race coupler deploying modified stepped impedance stub and interdigitated slot resonator for wide‐band harmonic suppression
Authors: Velan Sangeetha , Kanagasabai Malathi , Pakkathillam Jayaram Kizhekke , Palaniswamy Sandeep Kumar
Published: June 2016

This study presents the design of a flexible compact rat‐race coupler operating at 0.72 GHz on a 1 mm thick paper substrate. The ultra‐wide stop‐band effect caused due to the combination of the modified stepped impedance stub and the interdigitated resonator slot, offers suppression up to the 14th harmonic. The slow‐wave effect caused due to the resonator slot leads to 59.6% size reduction compared with the conventional coupler at the design frequency. The signal transmission through the coupler for different substrate deformation steps has been investigated. Stable responses are reported for the same, making the prototype suitable for flexible electronics applications.
Plug‐in repetitive control of single‐phase grid‐connected inverter for AC module applications
Authors: Evran Fatih
Published: June 2016

This study presents two‐stage inverter topology for single‐phase grid‐connected photovoltaic (PV) applications and its control implementations. The two‐stage systems are reliable and work well. Typically, the second stage inverts solar power into AC power, whereas the first stage which is used to increase low PV panel voltage can achieve maximum power point tracking. In this configuration, a boost or a flyback type DC/DC converter topology is usually employed. However, such converters have major drawbacks such as low efficiency and limited voltage gain due to power losses. In the proposed topology, a low‐voltage PV panel can be connected to power grid through solar inverter by using high‐gain DC/DC converter which has unique features such as galvanic isolation and continuous current for AC module applications. Conventional controller results in poor control performance due to the finite gain at desired frequencies. Hence, a plug‐in repetitive controller is proposed to obtain low total harmonic distortions (THDs). The performance of the proposed system is provided for the system which injects the PV panel current in the maximum power point voltage to a grid of 220 V(rms) at a power range of 150–300 W with a unity power factor and a low input current THD.
Positive dc corona inception on dielectric‐coated stranded conductors in air
Authors: Yi Yong , Zhang Chuyan , Wang Liming
Published: June 2016

In this study, the positive inception voltage of bare and dielectric‐coated stranded conductors has been researched by numerical calculations and corona cage experiments. The charge simulation method is used to calculate the potential gradient distribution of the coated stranded conductors. Then, based on the positive inception criterion, the photoionisation inception model considering the effective radiation wavelength is proposed and employed to evaluate the inception voltage of the coated stranded conductors. In addition, in the laboratory, the inception voltage test platform is build up to measure the inception voltage. The results reveal that with the increase of the coating layer thickness, the inception voltage increases. For the same thickness, the inception voltage reduces slightly with the increase of relative permittivity. The calculated values are in good agreement with experimental results of the laboratory corona cage. The conclusion lays a foundation for studying the effect of the coating layer on the corona performance.
Correction of cavity absorptance measure method for cryogenic radiometer
Authors: Yi Xiaolong , Fang Wei , Luo Yang , Xia Zhiwei , Wang Yupeng
Published: June 2016

As the reference detector of absolute radiance calibration primary radiometer (ARCPR) for space remote sensing, total solar irradiance (TSI) cavity is investigated to ensure the measurement accuracy. TSI cavity adopts a sloping bottom cavity. The geometrical parameters and paint material of sloping bottom cavity are both optimised to improve the invariance of absorptance in the environment of ground and space. The optimisation of substitution method is proposed to measure the average absorptance by two‐dimensional scan. The uniformity is evaluated by absorptance map. Experimental results illustrate that sloping bottom cavity has a super‐high absorptance of 0.999928 (wavelength is 632 nm), and the relative measure uncertainty is approximated to 6 ppm. Meanwhile, compared with the absorptance map of conical cavity, the sloping bottom design improves the uniformity of absorptance. Therefore, the sloping bottom cavity can be adopted as the reference detector of ARCPR. Furthermore, the optimised substitution method is suitable for the investigation of the blackbody cavity with super‐high absorptance.
Improvement of gas ultrasonic flowmeter measurement non‐linearity based on ray tracing method
Authors: Zheng Dandan , Mei Jianqiang , Wang Mi
Published: June 2016

Gas ultrasonic flowmeters are widely used in natural gas industry. When flow velocity achieves to tens of meters per second, the measurement error may appear significant non‐linearity with flow velocity increased. In order to solve this problem, reasons of non‐linearity are discussed based on the ray acoustics theory. First, the two‐dimensional ray tracing method is introduced and realised by Matlab. Second, both DN100 and DN500 diametric single path gas ultrasonic flowmeters are simulated, respectively. The ultrasonic wave propagation trajectory, transit time, path angle and receiving position of transducer are analysed with increasing flow velocities 1–50 m/s. Third, it is noted that the assumption of traditional velocity measurement model is not consistent with the actual ultrasound propagation. Therefore, a corrected model is proposed. Through comparing results of traditional and corrected models, the measurement error is reduced up to 4%, and the measurement non‐linearity is improved.
Modelling and evaluation of HF‐RFID signal propagation characterisations under material properties variation
Authors: Yin Aijun , Ren Hongji
Published: June 2016

Previous electromagnetic (EM) wave‐based approaches to evaluate material physical properties are focused on applications of GHz and THz. High‐frequency radio‐frequency identification (HF‐RFID, 13.56 MHz) is low‐cost and mostly used as communication solution. Material properties variation can be affected by damage (such as defects or fatigue). In this study, the authors present a preliminary study that applies HF‐RFID on non‐destructive testing and evaluation. The evaluation model of HF‐RFID signal propagation characterisations under material EM properties variation is demonstrated. Simulations and experiments for oil debris monitoring and metal surface defect detection are demonstrated and simulations are in good agreement with experiment results. (i) In oil debris monitoring experiment, as the debris amount in the 25 ml breaker increases from 0.0 to 2.0 g, penetration signal decreases by 7.8% and reflected signal increases by 174.3%. (ii) In metal surface defect experiment, as the defect size increases from 1 to 5 mm, reflected signal decreases by 1.0%. The authors’ work also presents a blueprint for non‐destructive testing method using other high‐frequency devices.
Safety of Switching Factor VIII Products in the Era of Evolving Concentrates: Myths and Facts
Authors: Coppola Antonio , Marrone Emiliana , Conca Paolo , Cimino Ernesto , Mormile Rosaria , Baldacci Erminia , Santoro Cristina
Published: June 2016

Recent advances in the development of factor VIII (FVIII) concentrates offer patients with hemophilia the opportunity to switch to products considered safer or with improved properties. In some cases, product switch occurs due to side effects, convenience issues, or economic reasons affecting clinical choices. Reluctance to change FVIII concentrates is shown by patients and also by their physicians, because of concerns in particular about the risk of inhibitor development. A literature review was performed to retrieve the best evidence regarding safety issues of switching FVIII concentrate in patients with severe hemophilia A. Product switch was not associated with an increased inhibitor risk in four studies in patients during the first 50 to 75 exposure days, or in three studies reporting national switches in Canada and United Kingdom. The latter, the only available study comparing switcher and nonswitcher patients, showed an inhibitor incidence similar to that historically reported in the United Kingdom. In 16 phase III clinical trials and 6 postmarketing studies of FVIII concentrates, few de novo inhibitors were detected in previously treated patients, mostly transient and low-titer, with some additional recurrent inhibitors in patients with previous positive testing. On the whole, although rigorous controlled studies are lacking, literature data do not support increased risk of inhibitor development or other safety issues related to product switch. Therefore, in the presence of clinical needs, the advantages of switching FVIII products should not be missed because of perceived more than evidence-based challenges, in particular in this era of products with improved properties recently introduced or available in few years. Caution, however, is suggested in patients with high inhibitor risk, including in those in concomitance with surgery or intensive treatment. A careful inhibitor testing prior to and after product switch is always needed, to identify real de novo inhibitors and to gather further information in the current evolving scenario, in particular comparing switch and nonswitch patients.
Understanding and eliminating artifact signals from diffusely scattered pump beam in measurements of rough samples by time-domain thermoreflectance (TDTR)
Authors: Sun Bo , Koh Yee Kan
Published: June 2016

Time-domain thermoreflectance (TDTR) is a pump-probe technique frequently applied to measure the thermal transport properties of bulk materials, nanostructures, and interfaces. One of the limitations of TDTR is that it can only be employed to samples with a fairly smooth surface. For rough samples, artifact signals are collected when the pump beam in TDTR measurements is diffusely scattered by the rough surface into the photodetector, rendering the TDTR measurements invalid. In this paper, we systemically studied the factors affecting the artifact signals due to the pump beam leaked into the photodetector and thus established the origin of the artifact signals. We find that signals from the leaked pump beam are modulated by the probe beam due to the phase rotation induced in the photodetector by the illumination of the probe beam. As a result of the modulation, artifact signals due to the leaked pump beam are registered in TDTR measurements as the out-of-phase signals. We then developed a simple approach to eliminate the artifact signals due to the leaked pump beam. We verify our leak-pump correction approach by measuring the thermal conductivity of a rough InN sample, when the signals from the leaked pump beam are significant. We also discuss the advantages of our new method over the two-tint approach and its limitations. Our new approach enables measurements of the thermal conductivity of rough samples using TDTR.
Defect-based graphene nanoribbon photodetectors: A numerical study
Authors: Zarei M. H. , Sharifi M. J.
Published: June 2016

Recently, some photodetectors based on graphene have been proposed. In all of these works, current generation was carried out by separation of photo-excited carriers using an electric field, either internal or external. In this work, a new method of producing current which is based on different transmission coefficients for electrons and holes when they travel toward any of the two contacts is proposed. To this end, a single Stone–Wales defect close to one of the two contacts was used to break the channel symmetry. In order to confirm the idea, the non-equilibrium Green's function formalism in real space in conjunction with the tight binding method was used in simulations. In addition, to clarify the results, we present a classical model in which different diffusion constants are assumed for the left going and the right going carriers. Additional simulations for different positions of the defect, different lengths of the ribbon, and different bias voltages were performed, and the results are included in this study.
Key scattering mechanisms limiting the lateral transport in a modulation-doped polar heterojunction
Authors: Tien Nguyen Thanh , Thao Dinh Nhu , Thao Pham Thi Bich , Quang Doan Nhat
Published: June 2016

We present a study of the lateral transport of a two-dimensional electron gas (2DEG) in a modulation-doped polar heterojunction (HJ). In contrast to previous studies, we assume that the Coulomb correlation among ionized impurities and among charged dislocations in the HJ is so strong that the 2DEG low-temperature mobility is not limited by impurity and dislocation scattering. The mobility, however, is specified by alloy disorder scattering and combined roughness scattering, which is the total effect induced by both the potential barrier and polarization roughness. The obtained results show that the alloy disorder and combined roughness scattering strongly depend on the alloy content and on the near-interface electron distribution. Our theory is capable of explaining the bell-shaped dependence of the lateral mobility on alloy content observed in AlGaN/GaN and on 2DEG density observed in AlN/GaN, which have not previously been explained.
Extracting water and ion distributions from solution x-ray scattering experiments
Authors: Nguyen Hung T. , Pabit Suzette A. , Pollack Lois , Case David A.
Published: June 2016

Small-angle X-ray scattering measurements can provide valuable information about the solvent environment around biomolecules, but it can be difficult to extract solvent-specific information from observed intensity profiles. Intensities are proportional to the square of scattering amplitudes, which are complex quantities. Amplitudes in the forward direction are real, and the contribution from a solute of known structure (and from the waters it excludes) can be estimated from theory; hence, the amplitude arising from the solvent environment can be computed by difference. We have found that this “square root subtraction scheme” can be extended to non-zero q values, out to 0.1 Å−1 for the systems considered here, since the phases arising from the solute and from the water environment are nearly identical in this angle range. This allows us to extract aspects of the water and ion distributions (beyond their total numbers), by combining experimental data for the complete system with calculations for the solutes. We use this approach to test molecular dynamics and integral-equation (3D-RISM (three-dimensional reference interaction site model)) models for solvent structure around myoglobin, lysozyme, and a 25 base-pair duplex DNA. Comparisons can be made both in Fourier space and in terms of the distribution of interatomic distances in real space. Generally, computed solvent distributions arising from the MD simulations fit experimental data better than those from 3D-RISM, even though the total small-angle X-ray scattering patterns are very similar; this illustrates the potential power of this sort of analysis to guide the development of computational models.
Chemical potential and entropy in monodisperse and polydisperse hard-sphere fluids using Widom’s particle insertion method and a pore size distribution-based insertion probability
Authors: Baranau Vasili , Tallarek Ulrich
Published: June 2016

We estimate the excess chemical potential Δμ and excess entropy per particle Δs of computer-generated, monodisperse and polydisperse, frictionless hard-sphere fluids. For this purpose, we utilize the Widom particle insertion method, which for hard-sphere systems relates Δμ to the probability to successfully (without intersections) insert a particle into a system. This insertion probability is evaluated directly for each configuration of hard spheres by extrapolating to infinity the pore radii (nearest-surface) distribution and integrating its tail. The estimates of Δμ and Δs are compared to (and comply well with) predictions from the Boublík–Mansoori–Carnahan–Starling–Leland equation of state. For polydisperse spheres, we employ log-normal particle radii distributions with polydispersities δ = 0.1, 0.2, and 0.3.
Improving retention time in tunnel field effect transistor based dynamic memory by back gate engineering
Authors: Navlakha Nupur , Lin Jyi-Tsong , Kranti Abhinav
Published: June 2016

In this work, we report on the impact of position, bias, and workfunction of back gate on retention time of Tunnel Field Effect Transistor (TFET) based dynamic memory in ultra thin buried oxide and Double Gate (DG) transistors. The front gate of the TFET is aligned at a partial portion of the semiconductor film and controls the read mechanism based on band-to-band tunneling. The back gate is engineered to improve the performance of the dynamic cell by positioning it at the region uncovered by the front gate where it forms a deep potential well. The physical well formed by the back gate misalignment is made more profound by using a p+ poly workfunction as it accumulates more holes in the storage region and forms a deep potential well that sustains holes for longer duration, thereby increasing the retention time. The retention time is also governed by the generation and recombination phenomenon which can be controlled through the applied bias at the back gate. The retention time attained is ∼2 s at a temperature of 85 °C through optimal back gate engineering in DG transistors. The work shows innovative viewpoints of transforming gate misalignment, traditionally considered detrimental into a unique opportunity, coupled with appropriate selection of back gate workfunction and bias to significantly improve the retention time of capacitorless dynamic memory.
Optimization of simultaneous production of waste cooking oil based-biodiesel using iron-manganese doped zirconia-supported molybdenum oxide nanoparticles catalyst
Authors: Alhassan Fatah H. , Rashid Umer , Taufiq-Yap Yun Hin
Published: June 2016

Biodiesel derived from simultaneous esterification and transesterification of waste cooking oil has been attracting consideration as a replacement green fuel for diesel fuels, as it is economically feasible and circumvents the issue of energy versus food, which is estimated to take place with current biodiesel production techniques. In this optimization study, iron-manganese doped zirconia-supported molybdenum oxide catalyst has been prepared and used in the synthesis of waste cooking oil based biodiesel by a simultaneous esterification and transesterification method. The catalyst is prepared via an impregnation method and consequently characterized by XRD, TEM, TGA (thermogravimetric analysis), TPD-NH3, and Brunauer–Emmer–Teller (BET) techniques. The simultaneous process for biodiesel production has been assessed and improved statistically via response surface methodology in combination with the central composite design. It has been established that the process for synthesis of waste cooking oil based biodiesel achieved about 96.8% biodiesel yield at a best condition of 200 °C, waste cooking oil/ methanol molar ratio of 1:30 and 5.0 wt. % as loading of the catalyst. The highest ester yield of 96.8% has been obtained due to the improved physicochemical properties of zirconia-supported molybdenum oxide catalyst which accesses diffusion of the reactants to the active sites.
Design of a hybrid advective-diffusive microfluidic system with ellipsometric detection for studying adsorption
Authors: Wang Lei , Zhao Cunlu , Wijnperlé Daniel , Duits Michel H. G. , Mugele Frieder
Published: June 2016

Establishing and maintaining concentration gradients that are stable in space and time is critical for applications that require screening the adsorption behavior of organic or inorganic species onto solid surfaces for wide ranges of fluid compositions. In this work, we present a design of a simple and compact microfluidic device based on steady-state diffusion of the analyte, between two control channels where liquid is pumped through. The device generates a near-linear distribution of concentrations. We demonstrate this via experiments with dye solutions and comparison to finite-element numerical simulations. In a subsequent step, the device is combined with total internal reflection ellipsometry to study the adsorption of (cat)ions on silica surfaces from CsCl solutions at variable pH. Such a combined setup permits a fast determination of an adsorption isotherm. The measured optical thickness is compared to calculations from a triple layer model for the ion distribution, where surface complexation reactions of the silica are taken into account. Our results show a clear enhancement of the ion adsorption with increasing pH, which can be well described with reasonable values for the equilibrium constants of the surface reactions.
Effect of medium range order on pulsed laser crystallization of amorphous germanium thin films
Authors: Li T. T. , Bayu Aji L. B. , Heo T. W. , Santala M. K. , Kucheyev S. O. , Campbell G. H.
Published: June 2016

Sputter deposited amorphous Ge thin films had their nanostructure altered by irradiation with high-energy Ar+ ions. The change in the structure resulted in a reduction in medium range order (MRO) characterized using fluctuation electron microscopy. The pulsed laser crystallization kinetics of the as-deposited versus irradiated materials were investigated using the dynamic transmission electron microscope operated in the multi-frame movie mode. The propagation rate of the crystallization front for the irradiated material was lower; the changes were correlated to the MRO difference and formation of a thin liquid layer during crystallization.
Three-dimensional concentration of light in deeply sub-wavelength, laterally tapered gap-plasmon nanocavities
Authors: Tagliabue Giulia , Poulikakos Dimos , Eghlidi Hadi
Published: June 2016

Gap-plasmons (GP) in metal-insulator-metal (MIM) structures have shown exceptional performance in guiding and concentrating light within deep subwavelength layers. Reported designs to date exploit tapered thicknesses of the insulating layer in order to confine and focus the GP mode. Here, we propose a mechanism for the three dimensional concentration of light in planar MIM structures which exploits exclusively the lateral tapering of the front metallic layer while keeping a constant thickness of the insulating layer. We demonstrate that an array of tapered planar GP nanocavities can efficiently concentrate light in all three dimensions. A semi-analytical, one-dimensional model provides understanding of the underlying physics and approximately predicts the behavior of the structure. Three-dimensional simulations are then used to precisely calculate the optical behavior. Cavities with effective volumes as small as 10−5 λ3 are achieved in an ultrathin MIM configuration. Our design is inherently capable of efficiently coupling with free-space radiation. In addition, being composed of two electrically continuous layers separated by an ultrathin dielectric spacer, it could find interesting applications in the area of active metamaterials or plasmonic photocatalysis where both electrical access and light concentration are required.