bluuebunny/crossref_metadata_2025 huggingface dataset:
Parametric method for spacecraft trajectory tracking control problem with stochastic thruster fault
Authors: Fu Yan‐Ming , Li Cheng‐Jing
Published: July 2016

This study deals with the spacecraft trajectory tracking control problem with stochastic thruster fault of the chaser spacecraft, whose aim is to make the output of the Markov jump linear system track the output of a given reference model. A new succinct general complete parametric expression for the tracking controller is established. Considering the actuator malfunction, a set of Clohessy–Wiltshire equations with Markov jump parameters are proposed to describe the relative motion while the target spacecraft into a circular orbit. A linear matrix inequality method is presented to make the Markov jump system stochastically stable and to guarantee the input constraints. Based on the theory of the generalised Sylvester equations, a parametric method is established for the model reference tracking problem. For certain systems, the proposed algorithm contains extra degrees of freedom in parametric design, which can be used to achieve some additional performance. The final numerical simulation results show the effectiveness of the proposed method.
Measurement error of non‐sinusoidal electrical power and energy caused by instrument transformers
Authors: Kaczmarek Michal
Published: July 2016

In the study the methodology for evaluation of the total harmonics additional electrical power and energy measurement error caused by usage of instrument transformers in the measuring system for transformation of distorted current/voltage is discussed. In order to avoid the need for accurate measure of phase angles of distorted current/voltage higher harmonics the percentage components of the composite error, caused by current/voltage transformer's phase displacements, may be calculated. Moreover, the factor to determine the impact of change of voltage and current transformers’ accuracy of distorted current/voltage transformation in relation to sinusoidal conditions on power and energy measurement error is proposed. Finally, it has been shown that current and voltage distortion does not necessarily mean an increase of measuring system additional measurement error of total active power caused by usage of inductive instrument transformers.
Partition‐composition method for online detection of interconnected power system transient stability
Authors: Zhao Shuai , Jia Hongjie , Fang Dazhong
Published: July 2016

A new partition‐composition method for online detection of transient stability of interconnected power system with the data from wide area measurement system (WAMS) is proposed. It consists of two parts: partition and composition. In the partition step, interconnected grids are divided into several local areas according to their geographical locations or ownership. Each area is modelled as an adjoint power system (APS) to determine its own synchronism. In the composition step, transient stability of entire grid is evaluated by the APS model of entire system composed with several key parameters of local areas, which can be directly derived from local WAMS. The proposed method only uses WAMS data, hence it is independent from the offline data, such as network topology, device model and system parameters. Another outstanding feature of the proposed method is that only a few key parameters are required to be transferred from the local control centres to the global control centre. These features are helpful for the interconnected grid with different owners since exhaustive data are unnecessary for the global control centre. Case studies on the 10‐generator New England system and one of 2007 operation cases of North China Power Grid validate its correctness and effectiveness.
Practical multi‐area bi‐objective environmental economic dispatch equipped with a hybrid gradient search method and improved Jaya algorithm
Authors: Azizipanah‐Abarghooee Rasoul , Dehghanian Payman , Terzija Vladimir
Published: July 2016

Generation dispatch decision making integrated into a centralised wholesale electricity market has been always a challenging concern for transmission system operators. The reason lies mainly in the complex and highly‐interconnected structure of the grid, escalated demand, and the crisis of the amount and price of energy. For the dispatch solutions to be highly reliable with an acceptable level of accuracy, several factors need to be taken into account, among which one can mention the valve‐point effect, multiple fuel options, disjoint prohibited zones, up/down ramp rate requirements of units, as well as the spinning reserve constraints which, in turn, intensify the non‐smoothness, non‐convexity, non‐linearity, and dynamic restriction of such combinatorial problems. This study proposes a new optimization toolset for the bi‐objective multi‐area economic dispatch problem to determine the transmission power flow and power output of units while satisfying system demand and security constraints at each area. The proposed architecture builds on an improved gradient‐based Jaya algorithm to generate a feasible set of Pareto‐optimal solutions corresponding to the operation cost and emission calculated through a new robust bi‐objective gradient‐based method. The projected algorithm is proved to be capable of finding the robust global or near‐global Pareto solutions fast and accurate.
Pico‐hydel hybrid power generation system with an open well energy storage
Authors: Thalamttathu Thankappan Anilkumar , Simon Sishaj Pulikottil , Nayak Panugothu Srinivasa Rao , Sundareswaran Kinattingal , Padhy Narayana Prasad
Published: July 2016

This study proposes an approach for off‐grid micro‐hybrid system model to represent the locally available sustainable and renewable energy sources (RESs). This model is comprised of wind and solar energy as primary sources along with a pumped storage unit (PSU) as backup. The proposed PSU is modelled with pico‐hydro turbines (PHTs) and an open well. The ground water in the open well is effectively utilised along with agriculture and domestic needs in rural areas. The depth of the open well is exploited as the working head for the PHT. The power dispatch of two PHTs at a constant operating head, using the standard lambda iteration method, is obtained ensuring optimal utilisation of the stored water. The performance of the proposed model is tested using solar irradiance and wind speed data during winter and rainy seasons. The ratio of expected input energy and load demand on the succeeding day is used to control the water discharge on the current day. This model taps the unused potential of the open well as an energy storage system. Thereby, it limits the usage of batteries in satisfying the basic load demand of domestic consumers who do not have access to grid electricity.
Evidence theory‐based identification of aging for capacitive voltage transformers
Authors: Daryani Narges , Seyedi Heresh
Published: July 2016

In this study, an aging identification approach is proposed for capacitive voltage transformers (CVTs). Aging is an unavoidable phenomenon which emerges and spreads in equipment structure and mainly affects the insulation parts. The aging may affect transformer output in its primary stages. If it grows, it may cause serious damages to the equipment, substation and the staff. Accordingly, it is necessary to diagnose the aging of CVTs in its primary steps in order to implement the required maintenance and repair. The proposed aging identification method is an efficient method which collects data from different sources in digital substations to diagnose aging in CVT structures. Moreover, the possible external disturbances are also taken into account. A modified method is proposed based on the distance between the evidences. In addition, the algorithm is capable to identify the CVTs providing bad data arising from their aging.
Impact of support schemes and market rules on renewable electricity generation and system operation: the Spanish case
Authors: Chaves‐Avila José Pablo , Banez‐Chicharro Fernando , Ramos Andrés
Published: July 2016

This study discusses the impact of market rules on the generation (and curtailment) from intermittent energy sources (IES), such as the design of support schemes, the priority dispatch rule for IES, negative prices and economic compensation for IES curtailment. It also describes the approaches applied in some European countries and alternative designs. An evaluation of these different market rules is assessed for the Spanish 2020 scenario by using a system operation model. The results show that with a feed‐in‐tariff and the priority dispatch rule, more generation from IES is fed‐in into the system, and lower emissions are obtained. With negative prices and demand response, the feed‐in‐tariff scheme provides lower demand costs. With market remuneration and ex‐post remuneration (as implemented in Spain in 2015), IES generation fed‐in in the system is reduced and demand costs are increased. Furthermore, the curtailment of IES increases with higher penetration levels of IES. The increase in the curtailment is significantly higher for wind power as generation and demand are less correlated than solar generation and demand. The design of curtailment compensation and support schemes together become crucial to incentivise IES investments with higher value for the system.
Wind power plants grid code compliance tests – Hydro‐Québec TransÉnergie experience
Authors: Asmine Mohamed , Langlois Charles‐Éric
Published: July 2016

This study presents the Hydro‐Québec TransÉnergie experience regarding the grid code compliance tests that have been performed for the integration of wind power plants using type‐III and type‐IV technologies. Tests discussed in this study were conducted in two phases: validation of the performance requirements for each project and type tests on a single wind turbine generator for each technology involved. The study presents examples of results for each test module and measurements from online monitoring. Technical challenges are discussed and performance issues that were raised through the process are explained.
Multi‐sensor fusion for robust target tracking in the simultaneous presence of set‐membership and stochastic Gaussian uncertainties
Authors: Lu Kelin , Zhou Rui
Published: July 2016

This study proposes a novel data fusion algorithm in sensor networks with simultaneous presence of set‐membership and stochastic Gaussian measurement uncertainties. The proposed method is grounded in the marriage of ellipsoidal calculus theory and data compression algorithm. The point‐valued measurement and the set‐valued measurement are compressed into a uniform framework during the estimation. An optimal Kalman gain is obtained that minimises the upper bound of the mean square error of the estimation set. The proposed algorithm is applied to the target tracking problem and the estimation results show that the proposed algorithm improves the tracking performance.
Energy conservation‐based thresholding for effective wavelet denoising of partial discharge signals
Authors: Hussein Ramy , Shaban Khaled Bashir , El‐Hag Ayman H.
Published: July 2016

Recent studies have shown that wavelet transform can effectively be used for noise reduction in the context of partial discharge (PD) signal detection and classification. Several thresholding approaches for wavelet denoising have been reported in the literature. In this study, a novel wavelet threshold estimation method, named energy conservation‐based thresholding (ECBT), is introduced. The proposed thresholding function is capable of conserving a significant portion of the original signal energy, while the threshold value is determined based on the relative difference between the original and noisy signal energies. The proposed method is first applied to PD signals contaminated with different levels of simulated noise. Results show that ECBT produces a denoised PD signal with higher signal‐to‐noise ratio (SNR) and less distortion than PDs produced by the existing wavelet methods. Then, ECBT is modified to address actual PD signals corrupted with real noise, where a robust SNR estimation method is derived to estimate the noise level embedded in the measured PD signals. The denoised PD signals indicate that the proposed method yields higher reduction in noise levels than other methods.
Processing of graphene into a cantilever beam structure using a focused ion beam
Authors: Matsui Kazuma , Takei Yusuke , Inaba Akira , Takahata Tomoyuki , Matsumoto Kiyoshi , Shimoyama Isao
Published: July 2016

A graphene cantilever beam of arbitrary shape by patterning suspended graphene using a focused ion beam (FIB) is fabricated. Suspended graphene was formed by transferring graphene over a trench structure and patterned the suspended graphene into a cantilever beam structure. When the suspended graphene is patterned by an FIB, the high‐ion irradiation of FIB deforms the shape of the cantilever beam; in contrast, low‐ion irradiation cannot penetrate the suspended graphene. An evaluation of the ion irradiation dose of the FIB and the damages caused to the suspended graphene confirmed that in the case of few‐layer graphene with a maximum of three layers, optimum processing can be performed by an ion irradiation of 6 × 1016 ions/cm2. Under this condition, a graphene cantilever beam with a width of 1.34 μm and a length of 2.13 μm could be fabricated. Furthermore, the Raman spectroscopy results indicate that the FIB process does not significantly change the properties of the graphene.
Solid‐state immobilisation of titanium dioxide nanoparticles onto nanoclay
Authors: Ghorbanpour Mohammad , Lotfiman Samaneh
Published: July 2016

The impregnation of nanoclay with TiO2 was carried out by new and fast method. Nanoclay was submitted only to a single step molten salt process. Scanning electron microscopy showed that TiO2 nanoparticles precipitated over the nanoclay surface after treatment. Structural characterisation of nanocomposite by X‐ray diffraction displayed the change of basal peak after even 1 min process at both temperatures. UV‐visible spectroscopy showed the presence of TiO2. However, the band gap was not affected by process temperature and time. XRF graphs revealed that by increasing temperature and time of the molten salt process, the amount of loaded titanium dioxide on the nanoclays was enhanced. Through this quick process, an inexpensive nanocomposite with properties comparable with those from more elaborate processes is produced.
From Simple Cyclic 1,3-Ketoamides to Complex Spirolactams by Supported Heterogeneous Organocatalysis with PS-BEMP
Authors: Benmaati Aouicha , Zahmani Hadjira , Hacini Salih , Menéndez José , Bugaut Xavier , Rodriguez Jean , Constantieux Thierry
Published: July 2016

The reaction between cyclic 1,3-ketoamides and Michael acceptors in the presence of a catalytic amount of a polymer-supported organobase PS-BEMP has been developed for a direct access to spirocyclic 1,3-ketolactams through a domino Michael addition/hemiacetalization sequence. The products could be isolated in high chemical yields and purities after simple filtration, and the catalyst could be re-used without any re-activation. These spirolactams, containing a hemiaminal moiety, may be viewed as precursors of N-acyliminium intermediates upon Lewis acid activation, which allowed various subsequent functionalizations leading to original polycyclic lactams.
Methods of Hearing Preservation during Cochlear Implantation
Authors: Khater Ahmed , El-Anwar Mohammad
Published: July 2016

Introduction Recent advances in surgical techniques and electrode design have made residual hearing preservation during cochlear implantation (CI) possible, achievable, and desirable.

Objectives The objective of this study was to review the literature regarding methods used for hearing preservation during CI surgery.

Data Synthesis We performed a search in the LILACS, MEDLINE, SciELO, PubMed databases, and Cochrane Library, using the keywords CI, hearing preservation, CI electrode design, and CI soft surgery. We fully read about 15 studies that met the criteria described in “study selection”. The studies showed that several factors could contribute to possible cochlear damage during or after CI surgery and must be kept in mind; mechanical damage during electrode insertion, shock waves in the perilymph fluid due to implantation, acoustic trauma due to drilling, loss of perilymph and disruption of inner ear fluid homeostasis, potential bacterial infection, and secondary intracochlear fibrous tissue formation. The desire to preserve residual hearing has led to the development of the soft-surgery protocols with its various components; avoiding entry of blood into the cochlea and the use of hyaluronate seem to be reasonably supported, whereas the use of topical steroids is questionable. The site of entry into the cochlea, electrode design, and the depth of insertion are also important contributing factors.

Conclusion Hearing preservation would be useful for CI patients to benefit from the residual low frequency, as well as for the children who could be candidate for future regenerative hair cell therapy.
Scientific advice in China: the changing role of the Chinese Academy of Sciences
Authors: Li Xiaoxuan , Yang Kejia , Xiao Xiaoxi
Published: July 2016

This article explores the changing role of the Chinese Academy of Sciences (CAS) in the national scientific advisory system in China from an historical perspective, which has been divided into three periods. Period I (from 1949 to 1976) relates to the era during which, since its establishment, CAS assumed the role of the top-level scientific advisor to the Chinese government, and its dual role of “scientific advisory body” and “science and technology administrative organ” were especially evident during the formulation of “The Twelve-Year National Long-term Outline for Science and Technology Development (1956–1967)”. During period II (from 1977 to 2011) the function of providing scientific advice to the government was restored after the “Cultural Revolution”, and CAS entered a new era of unprecedented prosperity and development. Finally, period III (from 2012 to present) includes Chinese President Xi Jinping taking office, and the central government encouraging the development of science and technology think tanks, using third-party evaluation as an important measure and approach to promote the reform of the government management system. In summary, the new government attaches great importance to CAS, urging it, as a third-party organization, to fully play its role as a scientific advisor and further develop its capability and approaches to consulting, and improve its organizational structure. Given its prominent position in the Chinese scientific advisory system, the changing role of CAS also reflects the characteristics and changes in China’s scientific advice throughout different periods. This article is published as part of a collection on scientific advice to governments.
The global greening of religion
Authors: Chaplin Jonathan
Published: July 2016

It is increasingly acknowledged that our escalating global environmental challenges cannot be adequately responded to by governmental bodies without a substantial upsurge of popular support for the far-reaching policy shifts widely seen as necessary. The search is thus on for the societal, cultural and moral energies that might inspire the large-scale consciousness-raising and mobilization required for such an upsurge. More recently, there has also been a growing recognition that, in a world where four-fifths of the population adheres to some form of spiritual tradition, religion may be one of those necessary sources. This article begins by identifying the remarkable upsurge of religiously inspired ecological concern over the last 30 years, noting that it has come to expression with special force in robust declarations on, and attempts to mobilize believers over, the issue of climate change. It then summarizes this phenomenon in terms of seven core commitments and concludes by reflecting briefly on its potential future influence.
A global reaction route mapping-based kinetic Monte Carlo algorithm
Authors: Mitchell Izaac , Irle Stephan , Page Alister J.
Published: July 2016

We propose a new on-the-fly kinetic Monte Carlo (KMC) method that is based on exhaustive potential energy surface searching carried out with the global reaction route mapping (GRRM) algorithm. Starting from any given equilibrium state, this GRRM-KMC algorithm performs a one-step GRRM search to identify all surrounding transition states. Intrinsic reaction coordinate pathways are then calculated to identify potential subsequent equilibrium states. Harmonic transition state theory is used to calculate rate constants for all potential pathways, before a standard KMC accept/reject selection is performed. The selected pathway is then used to propagate the system forward in time, which is calculated on the basis of 1st order kinetics. The GRRM-KMC algorithm is validated here in two challenging contexts: intramolecular proton transfer in malonaldehyde and surface carbon diffusion on an iron nanoparticle. We demonstrate that in both cases the GRRM-KMC method is capable of reproducing the 1st order kinetics observed during independent quantum chemical molecular dynamics simulations using the density-functional tight-binding potential.
Diamond-like-carbon nanoparticle production and agglomeration following UV multi-photon excitation of static naphthalene/helium gas mixtures
Authors: Walsh A. J. , Tielens A. G. G. M. , Ruth A. A.
Published: July 2016

We report the formation of nanoparticles with significant diamond character after UV multi-photon laser excitation of gaseous naphthalene, buffered in static helium gas, at room temperature. The nanoparticles are identified in situ by their absorption and scattering spectra between 400 and 850 nm, which are modeled using Mie theory. Comparisons of the particles’ spectroscopic and optical properties with those of carbonaceous materials indicate a sp3/sp2 hybridization ratio of 8:1 of the particles formed. The particle extinction in the closed static (unstirred) gas-phase system exhibits a complex and quasi-oscillatory time dependence for the duration of up to several hours with periods ranging from seconds to many minutes. The extinction dynamics of the system is based on a combination of transport features and particle interaction, predominantly agglomeration. The relatively long period of agglomeration allows for a unique analysis of the agglomeration process of diamond-like carbon nanoparticles in situ.
Photodissociation dynamics of the methyl perthiyl radical at 248 and 193 nm using fast-beam photofragment translational spectroscopy
Authors: Harrison Aaron W. , Ryazanov Mikhail , Sullivan Erin N. , Neumark Daniel M.
Published: July 2016

The photodissociation dynamics of the methyl perthiyl radical (CH3SS) have been investigated using fast-beam coincidence translational spectroscopy. Methyl perthiyl radicals were produced by photodetachment of the CH3SS− anion followed by photodissociation at 248 nm (5.0 eV) and 193 nm (6.4 eV). Photofragment mass distributions and translational energy distributions were measured at each dissociation wavelength. Experimental results show S atom loss as the dominant (96%) dissociation channel at 248 nm with a near parallel, anisotropic angular distribution and translational energy peaking near the maximal energy available to ground state CH3S and S fragments, indicating that the dissociation occurs along a repulsive excited state. At 193 nm, S atom loss remains the major fragmentation channel, although S2 loss becomes more competitive and constitutes 32% of the fragmentation. The translational energy distributions for both channels are very broad at this wavelength, suggesting the formation of the S2 and S atom products in several excited electronic states.
Observations of high vibrational levels of the 4fσ41Σu+ state of H2
Authors: Chartrand A. M. , Ekey R. C. , McCormack E. F.
Published: July 2016

Resonantly enhanced multiphoton ionization via the EF1Σg+, v′ = 6 double-well state has been used to probe the energy region below the third dissociation limit of H2 where several high vibrational levels of the 41Σu+ state are expected. Theoretical ab initio potential energy curves for this state predict a deep inner well and shallow outer well where vibrational levels above v = 8 are expected to exhibit the double-well character of the state. Since the 41Σu+ state has f-state character, transitions to it from the ground state are nominally forbidden. However, the d character of the outer well of the EF1Σg+ state allows access to this state. We report observations of transitions to the v = 9–12 levels of the 41Σu+ state and compare their energies to predicted energies calculated from an ab initio potential energy curve with adiabatic corrections. Assignments are based on measured energies and linewidths, rotational constants, and expected transition strengths. The amount of agreement between the predicted values and the observations is mixed, with the largest discrepancies arising for the v = 9 level, owing to strong nonadiabatic electronic mixing in this energy region.
Design and characterization of a prototype divertor viewing infrared video bolometer for NSTX-U
Authors: van Eden G. G. , Reinke M. L. , Peterson B. J. , Gray T. K. , Delgado-Aparicio L. F. , Jaworski M. A. , Lore J. , Mukai K. , Sano R. , Pandya S. N. , Morgan T. W.
Published: July 2016

The InfraRed Video Bolometer (IRVB) is a powerful tool to measure radiated power in magnetically confined plasmas due to its ability to obtain 2D images of plasma emission using a technique that is compatible with the fusion nuclear environment. A prototype IRVB has been developed and installed on NSTX-U to view the lower divertor. The IRVB is a pinhole camera which images radiation from the plasma onto a 2.5 μm thick, 9 × 7 cm2 Pt foil and monitors the resulting spatio-temporal temperature evolution using an IR camera. The power flux incident on the foil is calculated by solving the 2D+time heat diffusion equation, using the foil’s calibrated thermal properties. An optimized, high frame rate IRVB, is quantitatively compared to results from a resistive bolometer on the bench using a modulated 405 nm laser beam with variable power density and square wave modulation from 0.2 Hz to 250 Hz. The design of the NSTX-U system and benchtop characterization are presented where signal-to-noise ratios are assessed using three different IR cameras: FLIR A655sc, FLIR A6751sc, and SBF-161. The sensitivity of the IRVB equipped with the SBF-161 camera is found to be high enough to measure radiation features in the NSTX-U lower divertor as estimated using SOLPS modeling. The optimized IRVB has a frame rate up to 50 Hz, high enough to distinguish radiation during edge-localized-modes (ELMs) from that between ELMs.
Preparation and magnetic properties of phthalocyanine-based carbon materials containing transition metals
Authors: Honda Z. , Sato S. , Hagiwara M. , Kida T. , Sakai M. , Fukuda T. , Kamata N.
Published: July 2016

A simple method for the preparation of bulk quantities of magnetic carbon materials, which contain uniformly dispersed transition metals (M = Fe, Co, Ni, and Cu) as the magnetic components, is presented. By using highly chlorinated metal phthalocyanine as the building block and potassium as the coupling reagent, phthalocyanine-based carbon materials (PBCMs) containing transition metals were obtained. Our experiments demonstrate the structure of these PBCMs consists of transition metals embedded in graphitic carbon that includes a square planar MN4 magnetic core and the Fe and Co-PBCM possess spontaneous magnetization at room temperature. In addition, carbon-coated transition metal particles were obtained by the Wurtz-type reaction with excess amount of potassium coupling agent. The large transition metal surface area and magnetization of these M-PBCMs are useful for spintronic and catalytic applications.
Contactless measurement of equilibrium electron concentrations in n-type InAs/InAs1−xSbx type-II superlattices
Authors: Olson B. V. , Kadlec E. A. , Kim J. K. , Klem J. F. , Hawkins S. D. , Tauke-Pedretti A. , Coon W. T. , Fortune T. R. , Shaner E. A.
Published: July 2016

Measurements of the equilibrium majority carrier electron concentration (n0) in narrow-bandgap n-type InAs/InAs1−xSbx type-II superlattices are made using contactless time-resolved microwave reflectance (TMR). By calibrating TMR decays to the number of optically injected electron-hole pairs, direct conversion to carrier lifetimes as a function of excited carrier density is made and allowing for accurate measurement of n0. The temperature dependence of both n0 and the intrinsic carrier density (ni) are measured using this method, where n0 = 1 × 1015 cm−3 and ni = 1.74 × 1011 cm−3 at 100 K. These results provide non-destructive insight into critical parameters that directly determine infrared photodetector dark diffusion current.
Bound-bound transitions in hydrogen-like ions in dense quantum plasmas
Authors: Qi Y. Y. , Wang J. G. , Janev R. K.
Published: July 2016

The properties of bound-bound transitions in hydrogen-like ions in dense quantum plasmas, characterized by a cosine-Debye-Hückel interaction between charged particles, are studied in detail. The transition frequencies, oscillator strengths, and radiative transition probabilities of Lyman and Balmer series are calculated for a wide range of screening strengths of the interaction up to the n = 5 shell. For Δn≠0 transitions, all these quantities exhibit a significant decrease with increasing screening strength, while for the Δn=0 transitions and for the radiative lifetimes, the opposite is true. The present results are compared with those available from the literature. They are also compared with the results for the pure Debye-Hückel potential with the same screening strength.
Surface potential measurement on contact resistance of amorphous-InGaZnO thin film transistors by Kelvin probe force microscopy
Authors: Han Zhiheng , Xu Guangwei , Wang Wei , Lu Congyan , Lu Nianduan , Ji Zhuoyu , Li Ling , Liu Ming
Published: July 2016

Contact resistance plays an important role in amorphous InGaZnO (a-IGZO) thin film transistors (TFTs). In this paper, the surface potential distributions along the channel have been measured by using Kelvin probe force microscopy (KPFM) on operating a-IGZO TFTs, and sharp potential drops at the edges of source and drain were observed. The source and drain contact resistances can be extracted by dividing sharp potential drops with the corresponding drain to source current. It is found that the contact resistances could not be neglected compared with the whole channel resistances in the a-IGZO TFT, and the contact resistances decrease remarkably with increasing gate biased voltage. Our results suggest that the contact resistances can be controlled by tuning the gate biased voltage. Moreover, a transition from gradual channel approximation to space charge region was observed through the surface potential map directly when TFT operating from linear regime to saturation regime.
Cathodoluminescence study of luminescence centers in hexagonal and cubic phase GaN hetero-integrated on Si(100)
Authors: Liu R. , Bayram C.
Published: July 2016

Hexagonal and cubic GaN—integrated on on-axis Si(100) substrate by metalorganic chemical vapor deposition via selective epitaxy and hexagonal-to-cubic-phase transition, respectively—are studied by temperature- and injection-intensity-dependent cathodoluminescence to explore the origins of their respective luminescence centers. In hexagonal (cubic) GaN integrated on Si, we identify at room temperature the near band edge luminescence at 3.43 eV (3.22 eV), and a defect peak at 2.21 eV (2.72 eV). At low temperature, we report additional hexagonal (cubic) GaN bound exciton transition at 3.49 eV (3.28 eV), and a donor-to-acceptor transition at 3.31 eV (3.18 eV and 2.95 eV). In cubic GaN, two defect-related acceptor energies are identified as 110 and 360 meV. For hexagonal (cubic) GaN (using Debye Temperature (β) of 600 K), Varshni coefficients of α=7.37±0.13×10−4 (6.83±0.22×10−4)eV/K and E0=3.51±0.01 (3.31±0.01) eV are extracted. Hexagonal and cubic GaN integrated on CMOS compatible on-axis Si(100) are shown to be promising materials for next generation devices.
Stress compensation for arbitrary curvature control in vanadium dioxide phase transition actuators
Authors: Dong Kaichen , Lou Shuai , Choe Hwan Sung , Liu Kai , You Zheng , Yao Jie , Wu Junqiao
Published: July 2016

Due to its thermally driven structural phase transition, vanadium dioxide (VO2) has emerged as a promising material for micro/nano-actuators with superior volumetric work density, actuation amplitude, and repetition frequency. However, the high initial curvature of VO2 actuators severely obstructs the actuation performance and application. Here, we introduce a “seesaw” method of fabricating tri-layer cantilevers to compensate for the residual stress and realize nearly arbitrary curvature control of VO2 actuators. By simply adjusting the thicknesses of the individual layers, cantilevers with positive, zero, or negative curvatures can be engineered. The actuation amplitude can be decoupled from the curvature and controlled independently as well. Based on the experimentally measured residual stresses, we demonstrate sub-micron thick VO2 actuators with nearly zero final curvature and a high actuation amplitude simultaneously. This “seesaw” method can be further extended to the curvature engineering of other microelectromechanical system multi-layer structures where large stress-mismatch between layers are inevitable.
Zn precipitation and Li depletion in Zn implanted ZnO
Authors: Chan K. S. , Vines L. , Li L. , Jagadish C. , Svensson B. G. , Wong-Leung J.
Published: July 2016

Ion implantation of Zn substituting elements in ZnO has been shown to result in a dramatic Li depletion of several microns in hydrothermally grown ZnO. This has been ascribed to a burst of mobile Zn interstials. In this study, we seek to understand the reason behind this interstitial mediated transient enhanced diffusion in Li-containing ZnO samples after Zn implantation. ZnO wafers were implanted with Zn to two doses, 5 × 1015 cm−2 and 1 × 1017 cm−2. Secondary ion mass spectrometry was carried out to profile the Li depletion depth for different annealing temperatures between 600 and 800 °C. The 800 °C annealing had the most significant Li depletion of close to 60 μm. Transmission electron microscopy (TEM) was carried out in selected samples to identify the reason behind the Li depletion. In particular, TEM investigations of samples annealed at 750 °C show significant Zn precipitation just below the depth of the projected range of the implanted ions. We propose that the Zn precipitation is indicative of Zn supersaturation. Both the Li depletion and Zn precipitation are competing synchronous processes aimed at reducing the excess Zn interstitials.
Logic gates realized by nonvolatile GeTe/Sb2Te3 super lattice phase-change memory with a magnetic field input
Authors: Lu Bin , Cheng Xiaomin , Feng Jinlong , Guan Xiawei , Miao Xiangshui
Published: July 2016

Nonvolatile memory devices or circuits that can implement both storage and calculation are a crucial requirement for the efficiency improvement of modern computer. In this work, we realize logic functions by using [GeTe/Sb2Te3]n super lattice phase change memory (PCM) cell in which higher threshold voltage is needed for phase change with a magnetic field applied. First, the [GeTe/Sb2Te3]n super lattice cells were fabricated and the R-V curve was measured. Then we designed the logic circuits with the super lattice PCM cell verified by HSPICE simulation and experiments. Seven basic logic functions are first demonstrated in this letter; then several multi-input logic gates are presented. The proposed logic devices offer the advantages of simple structures and low power consumption, indicating that the super lattice PCM has the potential in the future nonvolatile central processing unit design, facilitating the development of massive parallel computing architecture.
Phosphoinositide 3-kinase inhibitors induce DNA damage through nucleoside depletion
Authors: Juvekar Ashish , Hu Hai , Yadegarynia Sina , Lyssiotis Costas A. , Ullas Soumya , Lien Evan C. , Bellinger Gary , Son Jaekyoung , Hok Rosanna C. , Seth Pankaj , Daly Michele B. , Kim Baek , Scully Ralph , Asara John M. , Cantley Lewis C. , Wulf Gerburg M.
Published: July 2016

Significance

Mutations in the PI3K pathway are highly prevalent in cancers, and isoform-specific and pan-PI3K inhibitors have entered clinical trials in both solid and hematologic malignancies. The PI3K δ-specific inhibitor idelalisib (in combination with rituximab) was recently approved for the treatment of chronic lymphocytic leukemia. However, identifying tumor types and biological mechanisms that predict for response to PI3K inhibitors as single agents or in combination has been a challenge. Our data indicate that PI3K inhibitors induce DNA damage in tumors that have defects in DNA damage-repair pathways and that they do so by impairing the production of Rib phosphate and amino acids needed for deoxynucleotide synthesis.
Assessing large-scale wildlife responses to human infrastructure development
Authors: Torres Aurora , Jaeger Jochen A. G. , Alonso Juan Carlos
Published: July 2016

Significance

Nature is increasingly threatened by rapid infrastructure expansion. For the first time, to our knowledge, we quantify the high pervasiveness of transportation infrastructure in all European countries. Unfortunately, spatial definition of the areas ecologically affected by infrastructure at large scales is complicated. Thus, we present a method for assessing the spatial extent of the impacts on birds and mammals at regional and national scales. As an illustration, its application to Spain shows that most of the country is affected, predicting moderate and severe declines for birds and mammals, respectively. The lack of areas that could be used as controls implies that scientists may no longer be able to measure the magnitude of road effects on wide-ranging mammals in most of Europe.
Helical arrays of U-shaped ATP synthase dimers form tubular cristae in ciliate mitochondria
Authors: Mühleip Alexander W. , Joos Friederike , Wigge Christoph , Frangakis Achilleas S. , Kühlbrandt Werner , Davies Karen M.
Published: July 2016

Significance

The structure of mitochondrial cristae in different species and tissues is highly variable. The molecular basis of these variations and their effect on mitochondrial function is not understood. Dimers of ATP synthase, the essential membrane protein complex that produces most of the ATP in the cell, are thought to shape lamellar cristae, for example in humans or yeasts. Here, we present the ATP synthase dimer structure from the ciliate
Paramecium tetraurelia,
which assembles into helical arrays around the outer perimeter of twisted tubular cristae. The similarities between the morphology of the helical arrays and the tubular cristae indicate that ATP synthase dimers are responsible for shaping the cristae of mitochondria.
Pathological ribonuclease H1 causes R-loop depletion and aberrant DNA segregation in mitochondria
Authors: Akman Gokhan , Desai Radha , Bailey Laura J. , Yasukawa Takehiro , Dalla Rosa Ilaria , Durigon Romina , Holmes J. Bradley , Moss Chloe F. , Mennuni Mara , Houlden Henry , Crouch Robert J. , Hanna Michael G. , Pitceathly Robert D. S. , Spinazzola Antonella , Holt Ian J.
Published: July 2016

Significance

The DNA in mitochondria is essential for efficient energy production. Critical for mitochondrial DNA replication and expression are sequences concentrated in the so-called control region. We report that many mitochondrial DNAs contain a triple-stranded region whose third strand is RNA and maps to the control region. These R-loops contribute to DNA architecture and replication in the mitochondria, and aberrant R-loop processing causes disease.
Two interferon-independent double-stranded RNA-induced host defense strategies suppress the common cold virus at warm temperature
Authors: Foxman Ellen F. , Storer James A. , Vanaja Kiran , Levchenko Andre , Iwasaki Akiko
Published: July 2016

Significance

Most strains of rhinovirus (RV), the common cold virus, replicate better at cool temperatures found in the nasal cavity (33–35°C) than at lung temperature (37°C). Recently, we found that although 37°C temperature suppressed RV growth by promoting IFN secretion, some antiviral effects of temperature were IFN-independent. Here, we used H1-HeLa cells and human bronchial epithelial cells to explore additional mechanisms underlying temperature-dependent RV growth. Using mathematical modeling and genetic approaches, we show that together, enhanced host cell death and the double-stranded RNA (dsRNA)-dependent activity of RNAseL contribute to restriction of RV growth at 37°C. These findings show that even in the absence of interferons, temperature has profound effects on antiviral defense that affect the outcome of common cold infections.
Utility functions predict variance and skewness risk preferences in monkeys
Authors: Genest Wilfried , Stauffer William R. , Schultz Wolfram
Published: July 2016

Significance

Utility, the key decision variable underlying economic choices, should represent risk, which is inherent to real-life decisions. We studied two prevalent forms of risk that are characterized by the spread (variance-risk) and asymmetry (skewness-risk) of rewards. We show that monkeys preferred higher variance and positively skewed gambles. Importantly, empirically estimated utility functions predicted both of these risk preferences. Thus, the abstract concept of utility seemed to explain primates’ choices under common forms of risk.
Socially selected ornaments influence hormone titers of signalers and receivers
Authors: Tibbetts Elizabeth A. , Crocker Katherine , Huang Zachary Y.
Published: July 2016

Significance

Despite the short-term benefits of dishonesty, animals typically communicate honestly. What prevents weak, low-quality individuals from cheating by signaling that they are strong? The general answer is that signals are costly, and only the best individuals can afford to signal strength. However, there are theoretical and empirical challenges associated with identifying the costs that maintain signal accuracy. Here, we provide a new perspective on honest communication by showing that wasps with dishonest signals are aggressively punished, and this punishment has lasting effects on the physiology of the dishonest signaler and those they interact with. We propose that interactions between behavioral and physiological costs of dishonesty could play an important role in maintaining honest communication over evolutionary time.
Peer review and competition in the Art Exhibition Game
Authors: Balietti Stefano , Goldstone Robert L. , Helbing Dirk
Published: July 2016

Significance

Competition is an essential mechanism in increasing the effort and performance of human groups in real life. However, competition has side effects: it can be detrimental to creativity and reduce cooperation. We conducted an experiment called the Art Exhibition Game to investigate the effect of competitive incentives in environments where the quality of creative products and the amount of innovation allowed are decided through peer review. Our approach is general and can provide insights in domains such as clinical evaluations, scientific admissibility, and science funding. Our results show that competition leads to more innovation but also to more unfair reviews and to a lower level of agreement between reviewers. Moreover, competition does not improve the average quality of published works.
Astrocytic β
2
-adrenergic receptors mediate hippocampal long-term memory consolidation
Authors: Gao Virginia , Suzuki Akinobu , Magistretti Pierre J. , Lengacher Sylvain , Pollonini Gabriella , Steinman Michael Q. , Alberini Cristina M.
Published: July 2016

Significance

Experiences are remembered long-term when these memories are formed in a state of arousal and heightened emotion. The arousal-induced release of noradrenaline is critical for modulating consolidation, the process that establishes long-term memory. Although the effects of pharmacological manipulation of adrenergic signaling on memory stability are already being investigated in the clinical setting, how adrenergic receptors mediate long-term memory consolidation remains unclear. This study reports a previously unidentified mechanism with important translational implications: The noradrenergic receptors that in the hippocampus mediate memory consolidation are β
2
-adrenergic receptors (β
2
ARs) expressed in astrocytes. These receptors are necessary for the learning-evoked release of lactate from astrocytes, which then is required to support the neuronal molecular changes essential for long-term memory formation.
Single-cell analysis delineates a trajectory toward the human early otic lineage
Authors: Ealy Megan , Ellwanger Daniel C. , Kosaric Nina , Stapper Andres P. , Heller Stefan
Published: July 2016

Significance

Understanding early human development relies on studies of in vitro-generated tissues from human embryonic or induced pluripotent stem cells that recapitulate in vivo cell types. End-point analyses of specific cell types can be hindered by inappropriate cell-culture conditions that may drive cells to undesired fates. We address these issues by reconstructing the trajectory of gene expression dynamics of 90 marker genes during early human otic development at the single-cell level. To determine the efficacy of our guidance protocol we compare these cells to native cells from the developing mouse otocyst. We find that otic induction follows the predicted dynamics of gene expression and resembles otic cells from native mouse tissue up to 12 days of culture.
The integration of quantitative genetics, paleontology, and neontology reveals genetic underpinnings of primate dental evolution
Authors: Hlusko Leslea J. , Schmitt Christopher A. , Monson Tesla A. , Brasil Marianne F. , Mahaney Michael C.
Published: July 2016

Significance

Experimental research on mice has yielded tremendous biological insight. However, the ∼140 million y of evolution that separate mice from humans pose a hurdle to direct application of this knowledge to humans. We report here that considerable progress for identifying genetically patterned skeletal phenotypes beyond the mouse model is possible through transdisciplinary approaches that include the anatomical sciences. Indeed, anatomy and paleontology offer unique opportunities through which to develop and test hypotheses about the underlying genetic mechanisms of the skeleton for taxa that are not well suited to experimental manipulation, such as ourselves.
Reversal of dendritic phenotypes in 16p11.2 microduplication mouse model neurons by pharmacological targeting of a network hub
Authors: Blizinsky Katherine D. , Diaz-Castro Blanca , Forrest Marc P. , Schürmann Britta , Bach Anthony P. , Martin-de-Saavedra Maria Dolores , Wang Lei , Csernansky John G. , Duan Jubao , Penzes Peter
Published: July 2016

Significance

The architecture of neuronal dendritic trees is crucial for brain connectivity, whereas dendritic abnormalities are associated with psychiatric disorders. Rare copy number variations (CNVs) are a category of mutations often associated with schizophrenia, autism, and other mental disorders. However, the genetic complexity of CNV disorders poses a serious challenge for the identification of experimentally approachable mechanisms. Here we used network analysis to identify the most topologically important hub in protein–protein interaction networks within such a CNV, and in broader gene networks of psychiatric CNVs. We then show that pharmacological targeting of this node reverses dendritic alterations in a neuronal model of this CNV, outlining a strategy for the analysis and reversal of cellular phenotypes in CNV-related psychiatric disorders.