bluuebunny/crossref_metadata_2025 huggingface dataset:
Enzymatic processing of natural fibres: white biotechnology for sustainable development
Authors: Shahid Mohammad , Mohammad Faqeer , Chen Guoqiang , Tang Ren-Cheng , Xing Tieling
Published: March 2016

Industrial biotechnology has the potential to fulfil many key criteria of greener textile production.
Elastomeric free-form blood vessels for interconnecting organs on chip systems
Authors: Zhang Weijia , Zhang Yu Shrike , Bakht Syeda Mahwish , Aleman Julio , Shin Su Ryon , Yue Kan , Sica Marco , Ribas João , Duchamp Margaux , Ju Jie , Sadeghian Ramin Banan , Kim Duckjin , Dokmeci Mehmet Remzi , Atala Anthony , Khademhosseini Ali
Published: March 2016

A novel form of a vascular module based on endothelialized PDMS hollow tubes was developed for integrating multiple organs-on-chips.
Optofluidic restricted imaging, spectroscopy and counting of nanoparticles by evanescent wave using immiscible liquids
Authors: Liang L. , Zuo Y. F. , Wu W. , Zhu X. Q. , Yang Y.
Published: March 2016

An integrated optofluidic chip for restricted imaging, spectroscopy and counting of nanoparticles using the evanescent wave of total internal reflection at the interface of immiscible flows.
Post-translational control of protein function with light using a LOV-intein fusion protein
Authors: Jones D. C. , Mistry I. N. , Tavassoli A.
Published: March 2016

Modified split-inteins are fused to the photosensitive LOV2 domain to enable photoactivated cis intein splicing.
Mutagenicity of N-acyloxy-N-alkoxyamides as an indicator of DNA intercalation part 1: evidence for naphthalene as a DNA intercalator
Authors: Banks Tony M. , Clay Samuel F. , Glover Stephen A. , Schumacher Rhiannon R.
Published: March 2016

Naphthalene substituents enhance mutagenicity ofN-acyloxy-N-alkoxyamides towardsS. typhimuriumTA100 to the extent of 4 log P, most likely through intercalative binding to DNA.
Facile synthesis of substituted 3-aminofurans through a tandem reaction of N-sulfonyl-1,2,3-triazoles with propargyl alcohols
Authors: Cheng Xing , Yu Yinghua , Mao Zhifeng , Chen Jianxin , Huang Xueliang
Published: March 2016

A relay catalysis strategy for substituted 3-aminofurans synthesis has been developed.
Transformable nanostructures of cholesteryl-containing rhomboidal metallacycles through hierarchical self-assembly
Authors: Chen Li-Jun , Jiang Bo , Yang Hai-Bo
Published: March 2016

Various interesting nanostructures such as flowers and tadpole shaped structures were successfully obtained from well-defined cholesteryl-containing rhomboidal metallacycles prepared by coordination-driven self-assembly.
Density functional theory study of Li binding to graphene
Authors: Yang Guangmin , Fan Xiaofeng , Liang Zhicong , Xu Qiang , Zheng Weitao
Published: March 2016

Using first-principle calculations, we studied the interaction between Li and graphene by considering the two kinds of models, which are related to the configurations of Li adsorption and the concentration of Li on graphene.
Facile one-pot preparation of chiral monoliths with a well-defined framework based on the thiol–ene click reaction for capillary liquid chromatography
Authors: Zhang Peng , Wang Jiannan , Yang Haiguan , Su Linjing , Xiong Yuhao , Ye Fanggui
Published: March 2016

A novel chiral cyclodextrin (CD) monolith was easily prepared via a one-pot process based on the thiol–ene click reaction of allyl-β-CD with pentaerythritol tetra-(3-mercaptopropionate) in a fused-silica capillary.
Synthesis, characterization and biological evaluation of a novel biscarboxymethyl-modified tetraphenylchlorin compound for photodynamic therapy
Authors: Liao Pingyong , Zhang Xianghua , Zhang Lijun , Wang Xinrong , Zhu Wei , Sun Jingjian , Yan Yijia , Zhang Lixin , Chen Na , Chen Zhilong
Published: March 2016

Compound BCTC is an effective and a highly promising antitumor agent for photodynamic therapy.
One-pot synthesis of acyloxy carbonyl compounds from ketones using a Pybox–copper(ii) catalyst
Authors: Jia Wei-Guo , Zhang Hui , Li Dan-Dan , Yan Li-Qin
Published: March 2016

An efficient one-pot method for the synthesis of acyloxycarbonyl compounds from ketones catalyzed by a Pybox–Cu(ii) complexes has been achieved under mild conditions.
Correction: Intrinsically conductive polymer binders for electrochemical capacitor application
Authors: Kang Minjeong , Lee Ji Eun , Shim Hyeon Woo , Jeong Min Seong , Im Won Bin , Yoon Hyeonseok
Published: March 2016

Correction for ‘Intrinsically conductive polymer binders for electrochemical capacitor application’ by M. Kang et al., RSC Adv., 2014, 4, 27939–27945.
B, N-codoped graphene nanoribbons supported Pd nanoparticles for ethanol electrooxidation enhancement
Authors: Liu Qi , Fan Jinchen , Min Yulin , Wu Tong , Lin Yan , Xu Qunjie
Published: March 2016

In this study, B, N-codoped graphene nanoribbons (BN-GNRs) were prepared on a large scale via a one-pot hydrothermal method with GNRs and an ammonium fluoroborate (NH4BF4) mixture and served as the support for Pd loading targeted for efficient ethanol electrooxidation.
Stretchable magneto-dielectric composites based on raspberry-shaped iron oxide nanostructures
Authors: Vural M. , Gerber O. , Pichon B. P. , Lemonnier S. , Barraud E. , Kempel L. C. , Begin-Colin S. , Kofinas P.
Published: March 2016

Stretchable magneto-dielectric composites prepared by raspberry-shaped iron oxide nanostructures with low loss at microwave frequencies.
A facile and visual approach for the detection of trace level ammonia vapours under ambient conditions
Authors: Kaloo Masood Ayoub , Raja Sekhar Adiki , Ramana Reddy R. V. , Raman Ramya Sunder , Sankar Jeyaraman
Published: March 2016

A highly sensitive aromatic nucleophilic substitution reaction between BODIPY dye (1) and ammonia is explored and demonstrated as a potential tool for ammonia vapor detection.
Identification of ferrichrome- and ferrioxamine B-mediated iron uptake by Aspergillus fumigatus
Authors: Park Yong-Sung , Kim Ju-Yeon , Yun Cheol-Won
Published: March 2016

Aspergillus fumigatus is an opportunistic fungal pathogen for immunocompromised patients, and genes involved in siderophore metabolism have been identified as virulence factors. Recently, we identified the membrane transporters sit1 and sit2, which are putative virulence factors of A. fumigatus; sit1 and sit2 are homologous to yeast Sit1, and sit1 and sit2 gene expression was up-regulated after iron depletion. When expressed heterologously in Saccharomyces cerevisiae, sit1 and sit2 were localized to the plasma membrane; sit1 efficiently complemented ferrichrome (FC) and ferrioxamine B (FOB) uptake in yeast cells, whereas sit2 complemented only FC uptake. Deletion of sit1 resulted in a decrease in FOB and FC uptake, and deletion of sit2 resulted in a decrease in FC uptake in A. fumigatus. It is of interest that a sit1 and sit2 double-deletion mutant resulted in a synergistic decrease in FC uptake activity. Both sit1 and sit2 were localized to the plasma membrane in A. fumigatus. The expression levels of the sit1 and sit2 genes were dependent on hapX under low-but not high-iron conditions. Furthermore, mirB, and sidA gene expression was up-regulated and sreA expression down-regulated when sit1 and sit2 were deleted. Although sit1 and sit2 failed to affect mouse survival rate, these genes affected conidial killing activity. Taken together, our results suggest that sit1 and sit2 are siderophore transporters and putative virulence factors localized to the plasma membrane.
Co-occurrence of analogous enzymes determines evolution of a novel (βα)8-isomerase sub-family after non-conserved mutations in flexible loop
Authors: Verduzco-Castro Ernesto A. , Michalska Karolina , Endres Michael , Juárez-Vazquez Ana L. , Noda-García Lianet , Chang Changsoo , Henry Christopher S. , Babnigg Gyorgy , Joachimiak Andrzej , Barona-Gómez Francisco
Published: March 2016

We investigate the evolution of co-occurring analogous enzymes involved in L-tryptophan and L-histidine biosynthesis in Actinobacteria. Phylogenetic analysis of trpF homologues, a missing gene in certain clades of this lineage whose absence is complemented by a dual-substrate HisA homologue, termed PriA, found that they fall into three categories: (i) trpF-1, an L-tryptophan biosynthetic gene horizontally acquired by certain Corynebacterium species; (ii) trpF-2, a paralogue known to be involved in synthesizing a pyrrolopyrrole moiety and (iii) trpF-3, a variable non-conserved orthologue of trpF-1. We previously investigated the effect of trpF-1 upon the evolution of PriA substrate specificity, but nothing is known about the relationship between trpF-3 and priA. After in vitro steady-state enzyme kinetics we found that trpF-3 encodes a phosphoribosyl anthranilate isomerase. However, mutation of this gene in Streptomyces sviceus did not lead to auxothrophy, as expected from the biosynthetic role of trpF-1. Biochemical characterization of a dozen co-occurring TrpF-2 or TrpF-3, with PriA homologues, explained the prototrophic phenotype, and unveiled an enzyme activity trade-off between TrpF and PriA. X-ray structural analysis suggests that the function of these PriA homologues is mediated by non-conserved mutations in the flexible L5 loop, which may be responsible for different substrate affinities. Thus, the PriA homologues that co-occur with TrpF-3 represent a novel enzyme family, termed PriB, which evolved in response to PRA isomerase activity. The characterization of co-occurring enzymes provides insights into the influence of functional redundancy on the evolution of enzyme function, which could be useful for enzyme functional annotation.
Compact filtering slot antenna with frequency agility for Wi‐Fi/LTE mobile applications
Authors: Soltanpour M. , Fakharian M.M.
Published: March 2016

A reconfigurable filtering slot antenna (filtesnna) for Wi‐Fi/LTE mobile systems is proposed. The reconfigurable filtesnna is based on integrating a switchable bandpass filter inside the feeding line of a slot antenna structure. This design is achieved by using an open/short‐ended inter‐digital E‐shaped patch via two integrated pin diodes within its structure. The proposed filtesnna has a small size of 0.25λ0 × 0.1λ0 (λ0 is the free‐space wavelength at 2.1 GHz). The filtesnna is designed at centre frequencies of 2.1/2.4 GHz with measured 10 dB return loss impedance bandwidths from 2.03 to 2.17 GHz or 2.37 to 2.51 GHz when the diodes are ON or OFF, respectively. A prototype of the reconfigurable filtesnna has been fabricated and measured. A good adaptation is acquired between the simulated and the measured results.
Joint algebraic coded modulation and lattice‐reduction‐aided preequalisation
Authors: Stern S. , Fischer R.F.H.
Published: March 2016

Lattice‐reduction‐aided (LRA) preequalisation for the multiple‐input/multiple‐output broadcast channel has most often been considered for the uncoded case so far. However, recent advantages in the closely related field of integer‐forcing equalisation, where the cancellation of the multiuser interference and the channel coding are combined, create doubt to this separated point of view. In this Letter, the philosophy of matching both the channel code and the complex‐valued signal constellation to the same finite‐field arithmetic is proposed. The consequences on the factorisation task present in LRA preequalisation are discussed and covered by numerical performance evaluations based on non‐binary low‐density parity‐check codes.
Video anomaly detection using deep incremental slow feature analysis network
Authors: Hu Xing , Hu Shiqiang , Huang Yingping , Zhang Huanlong , Wu Hanbing
Published: March 2016

Existing anomaly detection (AD) approaches rely on various hand‐crafted representations to represent video data and can be costly. The choice or designing of hand‐crafted representation can be difficult when faced with a new dataset without prior knowledge. Motivated by feature learning, e.g. deep leaning and the ability to directly learn useful representations and model high‐level abstraction from raw data, the authors investigate the possibility of using a universal approach. The objective is learning data‐driven high‐level representation for the task of video AD without relying on hand‐crafted representation. A deep incremental slow feature analysis (D‐IncSFA) network is constructed and applied to directly learning progressively abstract and global high‐level representations from raw data sequence. The D‐IncSFA network has the functionalities of both feature extractor and anomaly detector that make AD completion in one step. The proposed approach can precisely detect global anomaly such as crowd panic. To detect local anomaly, a set of anomaly maps, produced from the network at different scales, is used. The proposed approach is universal and convenient, working well in different types of scenarios with little human intervention and low memory and computational requirements. The advantages are validated by conducting extensive experiments on different challenge datasets.
Leakage current generation in view of circuit topology of non‐isolated full‐bridge neutral point clamped grid‐tied photovoltaic inverters
Authors: Anandababu Chakravartula , Fernandes Baylon G.
Published: March 2016

Full‐bridge neutral point clamped (NPC) non‐isolated inverter topologies are used to mitigate leakage current at switching frequency due to non‐ideal circuit parameters. Among these topologies, this current is the highest in optimised non‐isolated inverter (oH5I) despite lowest switch count. This study analyses the limitations of oH5I in mitigating the leakage current by considering the junction capacitance of switches into account. This analysis elucidates the dependency of common‐mode voltage (CMV) characteristics on circuit topology and dead time requirement. In order to ascertain this fact, a novel non‐isolated full‐bridge NPC inverter (NIFB‐NPCI) is proposed. The CMV characteristics of this inverter are analysed during mode transitions and compared with that in oH5I. A 1 kVA unified prototype circuit of these inverters is designed and fabricated for experimental validation. The circuit topology and dead time requirement of oH5I cause a spike in CMV during each mode transition. However, these limitations are addressed in the proposed inverter, and CMV is maintained at a constant value. Hence, NIFB‐NPCI evinces lower leakage current at switching frequency than oH5I. Therefore, the effect of topological limitation of full‐bridge NPC non‐isolated inverters on leakage current mitigation is validated.
Maximising revenue via optimal control of a concentrating solar thermal power plant with limited storage capacity
Authors: Cirocco Luigi Rocco , Belusko Martin , Bruno Frank , Boland John , Pudney Peter
Published: March 2016

Concentrating solar thermal power plants with thermal energy storage is a potential source of clean electrical power. This work has the same four optimal control modes established in a previous paper where Pontryagin's principle demonstrated that to maximise revenue from a plant with unlimited storage the optimal modes were to: (i) store all collected power, without generating; (ii) generate using collected power only; (iii) generate at maximum capacity using both collected and stored power; (iv) generate a maximum capacity, storing any surplus power. This paper presents an expanded analysis to cover a more realistic case where there is limited storage capacity, introducing 2 differences. First, it is sometimes necessary to discard power if the store is full. Second, the critical prices used to determine the optimal control can change whenever the store becomes full or empty. Again we use Pontragin's principle to derive necessary conditions for an optimal control and present an algorithm to find the sequence of critical prices required to construct it. The analysis gives more insight into the nature of the optimal control than mathematical programming or probabilistic search techniques, and the calculation is fast‐finding the optimal control for a yearlong operation in about 30 seconds.
The interdisciplinarity of critical discourse studies research
Authors: Unger Johann W
Published: March 2016

Interdisciplinarity has been a core tenet of critical discourse studies—a group of approaches to the analysis of texts in their social contexts—since its inception, in what may be seen as a reaction against the sometimes staid and rigid disciplinary boundaries of linguistics and other disciplines. Interdisciplinarity has also been seen as necessarily accompanying analyses of complex social problems such as racism, sexism or other forms of discrimination and social domination. The concept has been multiply re-examined, challenged and reaffirmed by critical discourse scholars (for instance, in Weiss and Wodak, 2003), and the present article continues this work by mapping out the present-day dimensions of interdisciplinarity in different approaches to critical discourse studies. It also attempts to juxtapose these various disciplinary developments, and consider whether interdisciplinarity in and of itself has come to be taken for granted. Finally, it raises questions about whether the move away from an emphasis on the analysis of social wrongs within some of the newer approaches to critical discourse studies may in time lead to a disciplinary schism, or whether the increasingly disciplinary nature of critical discourse studies itself may have become a problem. This article forms part of an ongoing thematic collection dedicated to the concept of interdisciplinarity.
Gendered performances in sport: an embodied approach
Authors: Wellard Ian
Published: March 2016

Despite significant advances in recent years, gender inequalities remain apparent within the context of sport participation and engagement. One of the problems, however, when addressing gender issues in sport is the continued assumption by many sport practitioners that the experiences of women and men will always be different because of perceived physiological characteristics. Adopting a focus based solely on perceived gendered differences often overlooks the importance of recognizing individual experience and the prevailing social influences that impact on participation such as age, class, race and ability. An embodied approach, as well as seeking to move beyond mind/body dualisms, incorporates the physiological with the social and psychological. Therefore, it is suggested that, although considerations of gender remain important, they need to be interpreted alongside other interconnecting and influential (at varying times and occasions) social and physical factors. It is argued that taking the body as a starting point opens up more possibilities to manoeuvre through the mine field that is gender and sport participation. The appeal of an embodied approach to the study of gender and sport is in its accommodation of a wider multidisciplinary lens. Particularly, by acknowledging the subjective, corporeal, lived experiences of sport engagement, an embodied approach offers a more flexible starting point to negotiate the theoretical and methodological challenges created by restrictive discourses of difference.
Investigation of extrinsic damping caused by magnetic dead layer in Ta-CoFeB-MgO multilayers with perpendicular anisotropy
Authors: Sato Noriyuki , O'Brien Kevin P. , Millard Kent , Doyle Brian , Oguz Kaan
Published: March 2016

We systematically investigated the influence of the dead layer, the oxidation degree of naturally oxidized MgO, the structure of adjacent nonmagnetic metal layers on the damping parameter, and the perpendicular anisotropy of Ta(Ru)/Co20Fe60B20/MgO and MgO/Co20Fe60B20/Ta films using the vector network analyzer ferromagnetic resonance measurement technique. MgO/Co20Fe60B20/Ta film shows almost twice larger extrinsic damping than that for Ta/Co20Fe60B20/MgO film, whereas the perpendicular anisotropy is much smaller. This two-fold enhancement of damping parameter is successfully explained by the extrinsic damping arises from the dead layer at the CoFeB-Ta interface through the Elliott-Yafet mechanism in addition to the conventional spin-pumping model. Furthermore, we found that the oxidation degree of naturally oxidized MgO has no significant impact on the damping parameter, while the perpendicular anisotropy for MgO/Co20Fe60B20/Ta film is enhanced by longer oxidation time.
The physics origin of the hierarchy of bodies in space
Authors: Bejan A. , Wagstaff R. W.
Published: March 2016

Here we show that bodies of the same size suspended uniformly in space constitute a system (a “suspension”) in a state of uniform volumetric tension because of mass-to-mass forces of attraction. The system “snaps” hierarchically, and evolves faster to a state of reduced tension when the bodies coalesce spontaneously nonuniformly, i.e., hierarchically, into few large and many small bodies suspended in the same space. Hierarchy, not uniformity, is the design that emerges, and it is in accord with the constructal law. The implications of this principle of physics in natural organization and evolution are discussed.
Iron phthalocyanine on Cu(111): Coverage-dependent assembly and symmetry breaking, temperature-induced homocoupling, and modification of the adsorbate-surface interaction by annealing
Authors: Snezhkova Olesia , Bischoff Felix , He Yuanqin , Wiengarten Alissa , Chaudhary Shilpi , Johansson Niclas , Schulte Karina , Knudsen Jan , Barth Johannes V. , Seufert Knud , Auwärter Willi , Schnadt Joachim
Published: March 2016

We have examined the geometric and electronic structures of iron phthalocyanine assemblies on a Cu(111) surface at different sub- to mono-layer coverages and the changes induced by thermal annealing at temperatures between 250 and 320 °C by scanning tunneling microscopy, x-ray photoelectron spectroscopy, and x-ray absorption spectroscopy. The symmetry breaking observed in scanning tunneling microscopy images is found to be coverage dependent and to persist upon annealing. Further, we find that annealing to temperatures between 300 and 320 °C leads to both desorption of iron phthalocyanine molecules from the surface and their agglomeration. We see clear evidence of temperature-induced homocoupling reactions of the iron phthalocyanine molecules following dehydrogenation of their isoindole rings, similar to what has been observed for related tetrapyrroles on transition metal surfaces. Finally, spectroscopy indicates a modified substrate-adsorbate interaction upon annealing with a shortened bond distance. This finding could potentially explain a changed reactivity of Cu-supported iron phthalocyanine in comparison to that of the pristine compound.
Increased light extraction efficiency from top-emitting organic light-emitting diodes employing a mask-free plasma-etched stochastic polymer surface
Authors: Park Woo-Young , Kwon Yongwon , Cheong Hee-Woon , Lee Changhee , Whang Ki-Woong
Published: March 2016

Top-emitting organic light-emitting diodes (TEOLEDs) are drawing interest as future devices for both high-quality display and lighting. However, the current TEOLEDs have external quantum efficiencies of approximately 20%, which still need improvement. To attain high device efficiencies in TEOLEDs, waveguide and surface plasmon polariton modes should be minimised. Many efforts have been made using nano- or micrometre-scale periodic gratings to extract the confined photons. However, significant angular distortion or colour shifts occur as the Bragg condition calls for. Here, an effective method is demonstrated for enhancing the light extraction efficiency from TEOLEDs employing a mask-free plasma-etched polymer surface with stochastically distributed nano-hemispheres. TEOLEDs with the stochastic polymer surface allowed us to achieve a device efficiency enhancement up to 1.55-fold relative to conventional devices without introducing spectral changes and angular emission distortion, unlike periodic grating-embedded devices. Because of the independence of the improvement from the particular emission wavelengths, the proposed TEOLEDs are attractive and practical for use in full colour and white lighting as well as display applications.
Interplay between structure and transport properties of molten salt mixtures of ZnCl2–NaCl–KCl: A molecular dynamics study
Authors: Manga Venkateswara Rao , Swinteck Nichlas , Bringuier Stefan , Lucas Pierre , Deymier Pierre , Muralidharan Krishna
Published: March 2016

Molten mixtures of network-forming covalently bonded ZnCl2 and network-modifying ionically bonded NaCl and KCl salts are investigated as high-temperature heat transfer fluids for concentrating solar power plants. Specifically, using molecular dynamics simulations, the interplay between the extent of the network structure, composition, and the transport properties (viscosity, thermal conductivity, and diffusion) of ZnCl2–NaCl–KCl molten salts is characterized. The Stokes-Einstein/Eyring relationship is found to break down in these network-forming liquids at high concentrations of ZnCl2 (>63 mol. %), while the Eyring relationship is seen with increasing KCl concentration. Further, the network modification due to the addition of K ions leads to formation of non-bridging terminal Cl ions, which in turn lead to a positive temperature dependence of thermal conductivity in these melts. This new understanding of transport in these ternary liquids enables the identification of appropriate concentrations of the network formers and network modifiers to design heat transfer fluids with desired transport properties for concentrating solar power plants.
Influence of mutations at the proximal histidine position on the Fe–O2 bond in hemoglobin from density functional theory
Authors: Todde Guido , Hovmöller Sven , Laaksonen Aatto
Published: March 2016

Four mutated hemoglobin (Hb) variants and wild type hemoglobin as a reference have been investigated using density functional theory methods focusing on oxygen binding. Dispersion-corrected B3LYP functional is used and found to provide reliable oxygen binding energies. It also correctly reproduces the spin distribution of both bound and free heme groups as well as provides correct geometries at their close vicinity. Mutations in hemoglobin are not only an intrigued biological problem and it is also highly important to understand their effects from a clinical point of view. This study clearly shows how even small structural differences close to the heme group can have a significant effect in reducing the oxygen binding of mutated hemoglobins and consequently affecting the health condition of the patient suffering from the mutations. All of the studied mutated Hb variants did exhibit much weaker binding of molecular oxygen compared to the wild type of hemoglobin.
First principles calculations of ternary wurtzite β-CuGaO2
Authors: Suzuki Issei , Nagatani Hiraku , Kita Masao , Iguchi Yuki , Sato Chiyuki , Yanagi Hiroshi , Ohashi Naoki , Omata Takahisa
Published: March 2016

The electronic structure of β-CuGaO2 was studied by first principles calculations and X-ray photoelectron spectroscopy (XPS), and the expected electrical and optical properties of this material were discussed. Density functional theory calculations using the local density approximation with corrections for on-site Coulomb interactions (LDA + U) with U = 5–7 eV reproduced well the experimentally obtained crystal structure and valence-band XPS spectrum. The calculated electronic structure indicates that β-CuGaO2 is a direct band gap semiconductor and its conduction band minimum and valence band maximum consist mainly of highly delocalized Ga 4s and Cu 4s states and relatively localized Cu 3d and O 2p states, respectively. The effective electron mass obtained under parabolic approximation is small (me*/m0 = 0.21), similar to common n-type oxide semiconductors, and the effective hole mass is relatively large (mh*/m0 = 1.7–5.1) although p-type conduction is experimentally observed. The direct and allowed band gap and large density of states near the valence band maximum result in a high absorption coefficient of 1 × 105 cm−1 near the absorption edge.
Evolution of plasma parameters in a He-N2/Ar magnetic pole enhanced inductive plasma source
Authors: Younus Maria , Rehman N. U. , Shafiq M. , Zakaullah M. , Abrar M.
Published: March 2016

A magnetic pole enhanced inductively coupled He-N2/Ar plasma is studied at low pressure, to monitor the effects of helium mixing on plasma parameters like electron number density  (ne), electron temperature  (Te), plasma potential (Vp) , and electron energy probability functions (EEPFs). An RF compensated Langmuir probe is employed to measure these plasma parameters. It is noted that electron number density increases with increasing RF power and helium concentration in the mixture, while it decreases with increase in filling gas pressure. On the other hand, electron temperature shows an increasing trend with helium concentration in the mixture. At low RF powers and low helium concentration in the mixture, EEPFs show a “bi-Maxwellian” distribution with pressure. While at RF powers greater than 50 W and higher helium concentration in the mixture, EEPFs evolve into “Maxwellian” distribution. The variation of skin depth with RF power and helium concentration in the mixture, and its relation with EEPF are also studied. The effect of helium concentrations on the temperatures of two electron groups ( Tbulk and  Ttail) in the “bi-Maxwellian” EEPFs is also observed. The temperature of low energy electron group ( Tbulk) shows significant increase with helium addition, while the temperature of tail electrons ( Ttail)  increases smoothly as compared to ( Tbulk).
Deposition and characterization of B4C/CeO2 multilayers at 6.x nm extreme ultraviolet wavelengths
Authors: Sertsu M. G. , Giglia A. , Brose S. , Park D. , Wang Z. S. , Mayer J. , Juschkin L. , Nicolosi P.
Published: March 2016

New multilayers of boron carbide/cerium dioxide (B4C/CeO2) combination on silicon (Si) substrate are manufactured to represent reflective-optics candidates for future lithography at 6.x nm wavelength. This is one of only a few attempts to make multilayers of this kind. Combination of several innovative experiments enables detailed study of optical properties, structural properties, and interface profiles of the multilayers in order to open up a room for further optimization of the manufacturing process. The interface profile is visualized by high-angle annular dark-field imaging which provides highly sensitive contrast to atomic number. Synchrotron based at-wavelength extreme ultraviolet (EUV) reflectance measurements near the boron (B) absorption edge allow derivation of optical parameters with high sensitivity to local atom interactions. X-ray reflectivity measurements at Cu-Kalpha (8 keV) determine the period of multilayers with high in-depth resolution. By combining these measurements and choosing robust nonlinear curve fitting algorithms, accuracy of the results has been significantly improved. It also enables a comprehensive characterization of multilayers. Interface diffusion is determined to be a major cause for the low reflectivity performance. Optical constants of B4C and CeO2 layers are derived in EUV wavelengths. Besides, optical properties and asymmetric thicknesses of inter-diffusion layers (interlayers) in EUV wavelengths near the boron edge are determined. Finally, ideal reflectivity of the B4C/CeO2 combination is calculated by using optical constants derived from the proposed measurements in order to evaluate the potentiality of the design.
Structure, ion transport, and relaxation dynamics of polyethylene oxide/poly (vinylidene fluoride co-hexafluoropropylene)—lithium bis(trifluoromethane sulfonyl) imide blend polymer electrolyte embedded with ionic liquid
Authors: Das S. , Ghosh A.
Published: March 2016

We have studied structure, ion transport, and relaxation dynamics in polyethylene oxide/poly (vinylidene fluoride-hexafluoropropylene)-lithium bis(trifluoromethane)sulfonimide blend polymer electrolytes embedded with 1-propyl-3-methyleimidazoliuum bis(trifluromethyle-sulfonyl)imide ionic liquid. Structural property and ion–polymer interaction of polymer electrolytes have been studied using X-ray diffraction and Raman spectroscopy. The addition of ionic liquid decreases glass transition temperature and reduces crystalline phase in the polymer matrix. It is also observed that surface becomes smooth with increase of ionic liquid content. The temperature dependence of the Li ion conductivity follows Vogel–Tammann–Fulcher type behaviour when a sufficient amount of ionic liquid is added to polymer matrix. The electric modulus has been studied using Havriliak–Negami function for the understanding of ion dynamics. The modulus data have been analyzed using non-exponential Kohlrausch–Williams–Watts function. It is observed that the non-exponential parameter β is quite lower than unity, suggesting existence of a non-exponential relaxation. The temperature dependence of the relaxation time also follows Vogel–Tammann–Fulcher relation for compositions with higher ionic liquid content.
Phase diagrams of charged colloidal rods: Can a uniaxial charge distribution break chiral symmetry?
Authors: Drwenski Tara , Dussi Simone , Hermes Michiel , Dijkstra Marjolein , van Roij René
Published: March 2016

We construct phase diagrams for charged rodlike colloids within the second-virial approximation as a function of rod concentration, salt concentration, and colloidal charge. Besides the expected isotropic-nematic transition, we also find parameter regimes with a coexistence between a nematic and a second, more highly aligned nematic phase including an isotropic-nematic-nematic triple point and a nematic-nematic critical point, which can all be explained in terms of the twisting effect. We compute the Frank elastic constants to see if the twist elastic constant can become negative, which would indicate the possibility of a cholesteric phase spontaneously forming. Although the twisting effect reduces the twist elastic constant, we find that it always remains positive. In addition, we find that for finite aspect-ratio rods the twist elastic constant is also always positive, such that there is no evidence of chiral symmetry breaking due to a uniaxial charge distribution.
Helical plasma striations in liners in the presence of an external axial magnetic field
Authors: Atoyan L. , Hammer D. A. , Kusse B. R. , Byvank T. , Cahill A. D. , Greenly J. B. , Pikuz S. A. , Shelkovenko T. A.
Published: March 2016

Awe et al. found on the 20 MA Z machine [Acta Phys. Pol. A 115, 956 (2009)] that applying an externally generated axial magnetic field to an imploding liner leads to a helical pattern in the liner when viewed with soft x-ray radiography ([Phys. Rev. Lett. 111, 235005 (2013)] and [Phys. Plasmas 21, 056303 (2014)]). Here, we show that this phenomenon is also observed in extreme ultraviolet self-emission images of 10 mm long cylindrical metal liners having varying diameters and varying wall thicknesses on a 1 MA, 100–200 ns pulsed power generator. The magnetic field in these experiments is created using either twisted return current wires positioned close to the liner, generating a time-varying Bz, or a Helmholtz coil, generating a steady-state Bz.
Modeling ballistic effects in frequency-dependent transient thermal transport using diffusion equations
Authors: Maassen Jesse , Lundstrom Mark
Published: March 2016

Understanding ballistic phonon transport effects in transient thermoreflectance experiments and explaining the observed deviations from classical theory remains a challenge. Diffusion equations are simple and computationally efficient but are widely believed to break down when the characteristic length scale is similar or less than the phonon mean-free-path. Building on our prior work, we demonstrate how well-known diffusion equations, namely, the hyperbolic heat equation and the Cattaneo equation, can be used to model ballistic phonon effects in frequency-dependent periodic steady-state thermal transport. Our analytical solutions are found to compare excellently to rigorous numerical results of the phonon Boltzmann transport equation. The correct physical boundary conditions can be different from those traditionally used and are paramount for accurately capturing ballistic effects. To illustrate the technique, we consider a simple model problem using two different, commonly used heating conditions. We demonstrate how this framework can easily handle detailed material properties, by considering the case of bulk silicon using a full phonon dispersion and mean-free-path distribution. This physically transparent approach provides clear insights into the nonequilibrium physics of quasi-ballistic phonon transport and its impact on thermal transport properties.
Evaluation of antimony segregation in InAs/InAs1−xSbx type-II superlattices grown by molecular beam epitaxy
Authors: Lu Jing , Luna Esperanza , Aoki Toshihiro , Steenbergen Elizabeth H. , Zhang Yong-Hang , Smith David J.
Published: March 2016

InAs/InAs1−xSbx type II superlattices designed for mid-wavelength infrared photo-detection have been studied using several electron microscopy methods, with specific attention directed towards interface chemical diffusion caused by Sb segregation. Reciprocal-space image analysis using the geometric phase method showed asymmetric interfacial strain profiles at the InAs-on-InAsSb interface. Measurement of local Sb compositional profiles across the superlattices using electron energy-loss spectroscopy and 002 dark-field imaging confirmed asymmetric Sb distribution, with the InAs-on-InAsSb interface being chemically graded. In contrast, the InAsSb-on-InAs interface showed a small intrinsic interface width. Careful evaluation of the experimental Sb composition profiles using a combined segregation and sigmoidal model reached quantitative agreement. Segregation dominated over the sigmoidal growth at the InAs-on-InAsSb interface, and the segregation probability of 0.81 ± 0.01 obtained from the two microscopy techniques agreed well within experimental error. Thus, 81% of Sb atoms from the topmost layers segregated into the next layer during growth causing the interfaces to be broadened over a length of ∼3 nm. This strong Sb segregation occurred throughout the whole superlattice stack, and would likely induce undesirable effects on band-gap engineering, such as blue-shift or broadening of the optical response, as well as weakened absorption.
Simulation and fabrication of 0–3 composite PZT films for ultrahigh frequency (100–300 MHz) ultrasonic transducers
Authors: Chen Xiaoyang , Fei Chunlong , Chen Zeyu , Chen Ruimin , Yu Ping , Chen Zhongping , Shung K. Kirk , Zhou Qifa
Published: March 2016

This paper presents simulation, fabrication, and characterization of single-element ultrahigh frequency (100–300-MHz) needle ultrasonic transducers based on 0–3 composite Pb(Zr0.52Ti0.48)O3 (PZT) films prepared by using composite ceramic sol-gel film and sol-infiltration technique. The center frequency of the developed transducer at 300-MHz was the highest frequency of PbTiO3 ceramic-based ultrasonic transducers ever reported. Furthermore, a brief description of the composite model was followed by the development of a new expression for predicting the longitudinal velocity, the clamped dielectric constant, and the complex electromechanical coupling coefficient kt of these films, which is very important in ultrasonic transducer design. Moreover, these parameters are difficult to obtain by measuring the frequency dependence of impedance and phase angle because of the weak signal of the previous 0–3 composite films transducer (>100 MHz). The modeling results show that the Cubes model with a geometric factor n = 0.05 fits well with the measured data. This model will be helpful for developing the 0–3 composite systems for ultrahigh frequency ultrasonic transducer design.
Diffusion Monte Carlo study on temporal evolution of entropy and free energy in nonequilibrium processes
Authors: Tanaka Shigenori
Published: March 2016

A computational scheme to describe the temporal evolution of thermodynamic functions in stochastic nonequilibrium processes of isothermal classical systems is proposed on the basis of overdamped Langevin equation under given potential and temperature. In this scheme the associated Fokker-Planck-Smoluchowski equation for the probability density function is transformed into the imaginary-time Schrödinger equation with an effective Hamiltonian. The propagator for the time-dependent wave function is expressed in the framework of the path integral formalism, which can thus represent the dynamical behaviors of nonequilibrium molecular systems such as those conformational changes observed in protein folding and ligand docking. The present study then employs the diffusion Monte Carlo method to efficiently simulate the relaxation dynamics of wave function in terms of random walker distribution, which in the long-time limit reduces to the ground-state eigenfunction corresponding to the equilibrium Boltzmann distribution. Utilizing this classical-quantum correspondence, we can describe the relaxation processes of thermodynamic functions as an approach to the equilibrium state with the lowest free energy. Performing illustrative calculations for some prototypical model potentials, the temporal evolutions of enthalpy, entropy, and free energy of the classical systems are explicitly demonstrated. When the walkers initially start from a localized configuration in one- or two-dimensional harmonic or double well potential, the increase of entropy usually dominates the relaxation dynamics toward the equilibrium state. However, when they start from a broadened initial distribution or go into a steep valley of potential, the dynamics are driven by the decrease of enthalpy, thus causing the decrease of entropy associated with the spatial localization. In the cases of one- and two-dimensional asymmetric double well potentials with two minimal points and an energy barrier between them, we observe a nonequilibrium behavior that the system entropy first increases with the broadening of the initially localized walker distribution and then it begins to decrease along with the trapping at the global minimum of the potential, thus leading to the minimization of the free energy.
Emittance and lifetime measurement with damping wigglers
Authors: Wang G. M. , Shaftan T. , Cheng W. X. , Guo W. , Ilinsky P. , Li Y. , Podobedov B. , Willeke F.
Published: March 2016

National Synchrotron Light Source II (NSLS-II) is a new third-generation storage ring light source at Brookhaven National Laboratory. The storage ring design calls for small horizontal emittance (<1 nm-rad) and diffraction-limited vertical emittance at 12 keV (8 pm-rad). Achieving low value of the beam size will enable novel user experiments with nm-range spatial and meV-energy resolution. The high-brightness NSLS-II lattice has been realized by implementing 30-cell double bend achromatic cells producing the horizontal emittance of 2 nm rad and then halving it further by using several Damping Wigglers (DWs). This paper is focused on characterization of the DW effects in the storage ring performance, namely, on reduction of the beam emittance, and corresponding changes in the energy spread and beam lifetime. The relevant beam parameters have been measured by the X-ray pinhole camera, beam position monitors, beam filling pattern monitor, and current transformers. In this paper, we compare the measured results of the beam performance with analytic estimates for the complement of the 3 DWs installed at the NSLS-II.
Note: Molecular diffusivity in a small pore zeolite measured by a variable pressure (piezometric) uptake method
Authors: Wang Fei , Kobayashi Yasukazu , Muhammad Usman , Wang Dezheng , Wang Yao
Published: March 2016

The use of numerical analysis to solve the diffusion equation in the uptake method allowed the measurement of molecular diffusivity in a zeolite with a variable pressure around it. The diffusivity was obtained from the data in the measurement of the adsorption isotherm, which means that the diffusivity measurement now needs neither a special instrument nor procedure. The diffusivities of all the gases are readily available from the measurement of their adsorption isotherms and these data include how the diffusivity changes versus adsorbed concentration. The modeling introduced can also be used for a zeolite with a surface barrier.
Characterization of the room temperature payload prototype for the cryogenic interferometric gravitational wave detector KAGRA
Authors: Peña Arellano Fabián Erasmo , Sekiguchi Takanori , Fujii Yoshinori , Takahashi Ryutaro , Barton Mark , Hirata Naoatsu , Shoda Ayaka , van Heijningen Joris , Flaminio Raffaele , DeSalvo Riccardo , Okutumi Koki , Akutsu Tomotada , Aso Yoichi , Ishizaki Hideharu , Ohishi Naoko , Yamamoto Kazuhiro , Uchiyama Takashi , Miyakawa Osamu , Kamiizumi Masahiro , Takamori Akiteru , Majorana Ettore , Agatsuma Kazuhiro , Hennes Eric , van den Brand Jo , Bertolini Alessandro
Published: March 2016

KAGRA is a cryogenic interferometric gravitational wave detector currently under construction in the Kamioka mine in Japan. Besides the cryogenic test masses, KAGRA will also rely on room temperature optics which will hang at the bottom of vibration isolation chains. The payload of each chain comprises an optic, a system to align it, and an active feedback system to damp the resonant motion of the suspension itself. This article describes the performance of a payload prototype that was assembled and tested in vacuum at the TAMA300 site at the NAOJ in Mitaka, Tokyo. We describe the mechanical components of the payload prototype and their functionality. A description of the active components of the feedback system and their capabilities is also given. The performance of the active system is illustrated by measuring the quality factors of some of the resonances of the suspension. Finally, the alignment capabilities offered by the payload are reported.
Supersampling method for efficient grid-based electronic structure calculations
Authors: Ryu Seongok , Choi Sunghwan , Hong Kwangwoo , Kim Woo Youn
Published: March 2016

The egg-box effect, the spurious variation of energy and force due to the discretization of continuous space, is an inherent vexing problem in grid-based electronic structure calculations. Its effective suppression allowing for large grid spacing is thus crucial for accurate and efficient computations. We here report that the supersampling method drastically alleviates it by eliminating the rapidly varying part of a target function along both radial and angular directions. In particular, the use of the sinc filtering function performs best because as an ideal low pass filter it clearly cuts out the high frequency region beyond allowed by a given grid spacing.
Note: Moissanite backing plates for use in diamond anvil high pressure cells
Authors: Pugh E.
Published: March 2016

The use of moissanite (single crystal SiC) for backing plates within diamond anvil cells (DACs) has been developed. These have significant technical advantages in certain experiments. For example, moissanite is non-magnetic so is suitable for use in high magnetic fields and for magnetization experiments. Being translucent to light, including x-rays, means that openings are not required in the backing plate and as such has significant mechanical advantages and can provide enhanced scattering angles for x-ray diffraction experiments. The new backing plates have been successfully tested to over 25 GPa using diamond anvils with 0.5 mm culets.