bluuebunny/crossref_metadata_2025 huggingface dataset:
Sulfonate-ended carbosilane dendrimers with a flexible scaffold cause inactivation of HIV-1 virions and gp120 shedding
Authors: Sepúlveda-Crespo Daniel , de la Mata Francisco J. , Gómez Rafael , Muñoz-Fernández Mª A.
Published: April 2018

Sulfonate-ended carbosilane dendrimers with a polyphenolic core cause destabilization of virions by gp120 shedding, p24 release and RNA degradation.
High frequency sonoATRP of 2-hydroxyethyl acrylate in an aqueous medium
Authors: Collins Joe , McKenzie Thomas G. , Nothling Mitchell D. , Ashokkumar Muthupandian , Qiao Greg G.
Published: April 2018

Controlled aqueous ATRP of 2-hydroxyethyl acrylate using high frequency ultrasound is presented for the first time.
Comprehensive studies on phosphoric acid treatment of porous titania toward titanium phosphate and pyrophosphate monoliths with pore hierarchy and a nanostructured pore surface
Authors: Zhu Yang , Hasegawa George , Kanamori Kazuyoshi , Nakanishi Kazuki
Published: April 2018

A reaction of porous titania monoliths in aq. H3PO4 provides hierarchically porous titanium phosphates with a variety of nanotextured surfaces.
CVD growth of continuous and spatially uniform single layer graphene across the grain boundary of preferred (111) oriented copper processed by sequential melting–resolidification–recrystallization
Authors: Sharma Indu , Dhakate Sanjay R. , Subhedar Kiran M.
Published: April 2018

CVD growth of continuous and spatially uniform single layer graphene on preferred (111) oriented copper processed by sequential melting–resolidification–recrystallization.
Controllable synthetic ion channels
Authors: Chen Jian-Yu , Hou Jun-Li
Published: April 2018

The controllable synthetic ion channels with voltage-, ligand- light- and mechano-gating, as well as rectifying behaviours are discussed in regarding to their construction strategies and functions.
Fast and simple transesterification of epoxidized soybean oil to prepare epoxy methyl esters at room temperature
Authors: Liu Wei , Duan Feifei , Bi Yanlan
Published: April 2018

A sustainable method has been developed for fast transesterification of epoxidized soybean oil (ESBO) to prepare epoxy methyl esters (ESBOME) at 25 °C with NaOH as catalyst.
Rational design of a new cytarabine-based prodrug for highly efficient oral delivery of cytarabine
Authors: Zhang Jing , Zhang Di , Hu Xu , Liu Ruiling , Li Zhonghao , Luan Yuxia
Published: April 2018

To overcome the drawbacks of cytarabine such as bad liposolubility and low bioavailability, we rationally designed a new cytarabine-based prodrug for oral cytarabine delivery, realizing significantly enhanced bioavailability for cancer therapy.
Lasing from dot-in-rod nanocrystals in planar polymer microcavities
Authors: Manfredi G. , Lova P. , Di Stasio F. , Rastogi P. , Krahne R. , Comoretto D.
Published: April 2018

We report on the production of an optically pumped vertical cavity laser made by polymer mirrors embedding inorganic core@shell nanocrystals.
The effect of sintering process on lithium ionic conductivity of Li6.4Al0.2La3Zr2O12 garnet produced by solid-state synthesis
Authors: Xue Wenjuan , Yang Yaping , Yang Qiaoling , Liu Yuping , Wang Lian , Chen Changguo , Cheng Renju
Published: April 2018

The synergistic effects of Li concentration and relative density determined the Li+ ionic conductivity.
Weavable asymmetric carbon nanotube yarn supercapacitor for electronic textiles
Authors: Choi Changsoon , Park Jong Woo , Kim Keon Jung , Lee Duck Weon , de Andrade Mônica Jung , Kim Shi Hyeong , Gambhir Sanjeev , Spinks Geoffrey M. , Baughman Ray H. , Kim Seon Jeong
Published: April 2018

Yarn type asymmetric supercapacitor with high weight ratio of rGO in anode for wearable electronics.
An optimized procedure for direct access to 1H-indazole-3-carboxaldehyde derivatives by nitrosation of indoles
Authors: Chevalier Arnaud , Ouahrouch Abdelaaziz , Arnaud Alexandre , Gallavardin Thibault , Franck Xavier
Published: April 2018

The nitrosation of indoles under slightly acidic conditions and reverse addition conditions leads to the preparation of the corresponding indazole-3-carboxaldehydes in high yields and greatly minimizes side reactions.
Anti-inflammatory butenolide derivatives from the coral-derived fungus Aspergillus terreus and structure revisions of aspernolides D and G, butyrolactone VI and 4′,8′′-diacetoxy butyrolactone VI
Authors: Liu Mengting , Zhou Qun , Wang Jianping , Liu Junjun , Qi Changxing , Lai Yongji , Zhu Hucheng , Xue Yongbo , Hu Zhengxi , Zhang Yonghui
Published: April 2018

Chemical investigation of the coral-derived fungus Aspergillus terreus led to the discovery of ten butenolide derivatives (1–10), including four new ones (1–4).
Branched copolymer-stabilised nanoemulsions as new candidate oral drug delivery systems
Authors: Hobson James J. , Edwards Stephanie , Slater Rebecca. A. , Martin Philip , Owen Andrew , Rannard Steve P.
Published: April 2018

Branched copolymers offer very efficient nanoemulsion stabilisers with benefits for oral drug delivery.
Temperature-tuned ferromagnetism in hydrogenated multilayer graphene
Authors: Zhao Man , Xiao He , Chen Shuai , Hu Tianjun , Jia Jianfeng , Wu Haishun
Published: April 2018

Hydrogenated multilayer graphene was prepared by a facile electrochemical cathodic method and its ferromagnetism was tuned through thermal annealing.
Iron-catalyzed urea synthesis: dehydrogenative coupling of methanol and amines
Authors: Lane Elizabeth M. , Hazari Nilay , Bernskoetter Wesley H.
Published: April 2018

An iron catalyzed method for selective urea synthesis is described. This approach couples methanol and amines to generate diverse organic ureas.
Electrochemical imaging of cells and tissues
Authors: Lin Tzu-En , Rapino Stefania , Girault Hubert H. , Lesch Andreas
Published: April 2018

This minireview summarizes the recent achievements of electrochemical imaging platforms to map cellular functions in biological specimens using electrochemical scanning nano/micro-probe microscopy and 2D chips containing microelectrode arrays.
Maximizing tandem solar cell power extraction using a three-terminal design
Authors: Warren Emily L. , Deceglie Michael G. , Rienäcker Michael , Peibst Robby , Tamboli Adele C. , Stradins Paul
Published: April 2018

Three-terminal tandem solar cells can provide a robust operating mechanism to efficiently capture the solar spectrum without the need to current match sub-cells or fabricate complicated metal interconnects.
Phosphorylated graphene monoliths with high mixed proton/electron conductivity
Authors: Cao Li , Wu Hong , Mu Zehua , He Xueyi , Wang Chongbin , Li Jinzhao , Li Yan , Xu Mingzhao , Jiang Zhongyi
Published: April 2018

A single-phase mixed ionic–electronic conductor (MIEC) with long-range ordered transport nanochannels is explored using phosphorylated graphene nanosheets as building blocks.
An ATP/ATPase responsive supramolecular fluorescent hydrogel constructedviaelectrostatic interactions between poly(sodiump-styrenesulfonate) and a tetraphenylethene derivative
Authors: Wang Hu , Ji Xiaofan , Li Yang , Li Zhengtao , Tang Guping , Huang Feihe
Published: April 2018

We report a supramolecular fluorescent hydrogel based on poly(sodiump-styrenesulfonate) and a tetraphenylethene derivative.
Metal free room temperature phosphorescence from molecular self-interactions in the solid state
Authors: Forni Alessandra , Lucenti Elena , Botta Chiara , Cariati Elena
Published: April 2018

Purely organic materials showing solid state room temperature phosphorescence (RTP) are receiving an ever growing interest due to their low toxicity, cost and environmental load compared to their organometallic counterparts.
A search for transiting planets in the β Pictoris system
Authors: Mol Lous M. , Weenk E. , Kenworthy M. A. , Zwintz K. , Kuschnig R.
Published: April 2018

Context. Transiting exoplanets provide an opportunity for the characterization of their atmospheres, and finding the brightest star in the sky with a transiting planet enables high signal-to-noise ratio observations. The Kepler satellite has detected over 365 multiple transiting exoplanet systems, a large fraction of which have nearly coplanar orbits. If one planet is seen to transit the star, then it is likely that other planets in the system will transit the star too. The bright (V = 3.86) star β Pictoris is a nearby young star with a debris disk and gas giant exoplanet, β Pictoris b, in a multi-decade orbit around it. Both the planet’s orbit and disk are almost edge-on to our line of sight.

Aims. We carry out a search for any transiting planets in the β Pictoris system with orbits of less than 30 days that are coplanar with the planet β Pictoris b.

Methods. We search for a planetary transit using data from the BRITE-Constellation nanosatellite BRITE-Heweliusz, analyzing the photometry using the Box-Fitting Least Squares Algorithm (BLS). The sensitivity of the method is verified by injection of artificial planetary transit signals using the Bad-Ass Transit Model cAlculatioN (BATMAN) code.

Results. No planet was found in the BRITE-Constellation data set. We rule out planets larger than 0.6 RJ for periods of less than 5 days, larger than 0.75 RJ for periods of less than 10 days, and larger than 1.05 RJ for periods of less than 20 days.
On the formation of runaway stars BN and x in the Orion Nebula Cluster
Authors: Farias J. P. , Tan J. C.
Published: April 2018

We explore scenarios for the dynamical ejection of stars BN and x from source I in the Kleinmann-Low nebula of the Orion Nebula Cluster (ONC), which is important because it is the closest region of massive star formation. This ejection would cause source I to become a close binary or a merger product of two stars. We thus consider binary-binary encounters as the mechanism to produce this event. By running a large suite of N-body simulations, we find that it is nearly impossible to match the observations when using the commonly adopted masses for the participants, especially a source I mass of 7 M⊙. The only way to recreate the event is if source I is more massive, that is, ~20 M⊙. However, even in this case, the likelihood of reproducing the observed system is low. We discuss the implications of these results for understanding this important star-forming region.
Catching drifting pebbles
Authors: Ormel Chris W , Liu Beibei
Published: April 2018

Turbulence plays a key role in the transport of pebble-sized particles. It also affects the ability of pebbles to be accreted by protoplanets because it stirs pebbles out of the disk midplane. In addition, turbulence suppresses pebble accretion once the relative velocities become too high for the settling mechanism to be viable. Following Paper I, we aim to quantify these effects by calculating the pebble accretion efficiency ε using three-body simulations. To model the effect of turbulence on the pebbles, we derive a stochastic equation of motion (SEOM) applicable to stratified disk configurations. In the strong coupling limit (ignoring particle inertia) the limiting form of this equation agrees with previous works. We conduct a parameter study and calculate ε in 3D, varying pebble and gas turbulence properties and accounting for the planet inclination. We find that strong turbulence suppresses pebble accretion through turbulent diffusion, agreeing closely with previous works. Another reduction of ε occurs when the turbulent rms motions are high and the settling mechanism fails. In terms of efficiency, the outer disk regions are more affected by turbulence than the inner regions. At the location of the H2O iceline, planets around low-mass stars achieve much higher efficiencies. Including the results from Paper I, we present a framework to obtain ε under general circumstances.
Radial migration in a stellar galactic disc with thick components
Authors: Halle A. , Di Matteo P. , Haywood M. , Combes F.
Published: April 2018

We study how radial migration affects the stars of a galaxy with a thin stellar disc and thicker stellar components. The simulated galaxy has a strong bar and lasting spiral arms. We find that the amplitude of the churning (change in angular momentum) is similar for thin and thick components, and of limited amplitude, and that stars of all components can be trapped at the corotation of the bar. With the exception of those stars trapped at the corotation, we find that stars far from their initial guiding radius are more likely to be so due to blurring rather than churning effects. We compare the simulation to orbits integration with a fixed gravitational potential rotating at a constant speed. In the latter case, stars trapped at corotation are churned periodically outside and inside the corotation radius, with a zero net average. However, as the bar speed of the simulated galaxy decreases and its corotation radius increases, stars trapped at corotation for several Gyrs can be churned on average outwards. In this work we have studied the location of extreme migrators (stars experimenting the largest churning) and find that extreme migrators come from regions on the leading side of the effective potential local maxima.
Chemical composition of giant stars in the open cluster IC 4756
Authors: Bagdonas Vilius , Drazdauskas Arnas , Tautvaišienė Gražina , Smiljanic Rodolfo , Chorniy Yuriy
Published: April 2018

Context. Homogeneous investigations of red giant stars in open clusters contribute to studies of internal evolutionary mixing processes inside stars, which are reflected in abundances of mixing-sensitive chemical elements like carbon, nitrogen, and sodium, while α- and neutron-capture element abundances are useful in tracing the Galactic chemical evolution.

Aims. The main aim of this study is a comprehensive chemical analysis of red giant stars in the open cluster IC 4756, including determinations of 12C∕13C and C/N abundance ratios, and comparisons of the results with theoretical models of stellar and Galactic chemical evolution.

Methods. We used a classical differential model atmosphere method to analyse high-resolution spectra obtained with the FEROS spectrograph on the 2.2 m MPG/ESO Telescope. The carbon, nitrogen, and oxygen abundances, 12C∕13C ratios, and neutron-capture element abundances were determined using synthetic spectra, and the main atmospheric parameters and abundances of other chemical elements were determined from equivalent widths of spectral lines.

Results. We have determined abundances of 23 chemical elements for 13 evolved stars and 12C∕13C ratios for six stars of IC 4756. The mean metallicity of this cluster, as determined from nine definite member stars, is very close to solar – [Fe/H] = − 0.02 ± 0.01. Abundances of carbon, nitrogen, and sodium exhibit alterations caused by extra-mixing: the mean 12C∕13C ratio is lowered to 19 ± 1.4, the C/N ratio is lowered to 0.79 ± 0.05, and the mean [Na/Fe] value, corrected for deviations from the local thermodynamical equilibrium encountered, is enhanced by 0.14 ± 0.05 dex. We compared our results to those by other authors and theoretical models.

Conclusions. Comparison of the α-element results with the theoretical models shows that they follow the thin disc α-element trends. Being relatively young (~ 800 Myr), the open cluster IC 4756 displays a moderate enrichment of s-process-dominated chemical elements compared to the Galactic thin disc model and confirms the enrichment of s-process-dominated elements in young open clusters compared to the older ones. The r-process-dominated element europium abundance agrees with the thin disc abundance. From the comparison of our results for mixing-sensitive chemical elements and the theoretical models, we can see that the mean values of 12C∕13C, C/N, and [Na/Fe] ratios lie between the model with only the thermohaline extra-mixing included and the model which also includes the rotation-induced mixing. The rotation was most probably smaller in the investigated IC 4756 stars than 30% of the critical rotation velocity when they were on the main sequence.
The use of the DInSAR method in the monitoring of road damage caused by mining activities
Authors: Murdzek Radosław , Malik Hubert , Leśniak Andrzej
Published: April 2018

This paper reviews existing remote sensing methods of road damage detection and demonstrates the possibility of using DInSAR (Differential Interferometry SAR) method to identify endangered road sections. In this study two radar images collected by Sentinel-1 satellite have been used. Images were acquired with 24 days interval in 2015. The analysis allowed to estimate the scale of the post-mining deformation that occurred in Upper Silesia and to indicate areas where road infrastructure is particularly vulnerable to damage.
Ground subsidence information as a valuable layer in GIS analysis
Authors: Murdzek Radosław , Malik Hubert , Leśniak Andrzej
Published: April 2018

Among the technologies used to improve functioning of local governments the geographic information systems (GIS) are widely used. GIS tools allow to simultaneously integrate spatial data resources, analyse them, process and use them to make strategic decisions. Nowadays GIS analysis is widely used in spatial planning or environmental protection. In these applications a number of spatial information are utilized, but rarely it is an information about environmental hazards. This paper includes information about ground subsidence that occurred in USCB mining area into GIS analysis. Monitoring of this phenomenon can be carried out using the radar differential interferometry (DInSAR) method.
The influence of the fault zone width on land surface vibrations after the high-energy tremor in the “Rydułtowy-Anna” hard coal mine
Authors: Pilecka Elżbieta , Szwarkowski Dariusz
Published: April 2018

In the article, a numerical analysis of the impact of the width of the fault zone on land surface tremors on the area of the “Rydułtowy – Anna” hard coal mine was performed. The analysis covered the dynamic impact of the actual seismic wave after the high-energy tremor of 7 June 2013. Vibrations on the land surface are a measure of the mining damage risk. It is particularly the horizontal components of land vibrations that are dangerous to buildings which is reflected in the Mining Scales of Intensity (GSI) of vibrations. The run of a seismic wave in the rock mass from the hypocenter to the area’s surface depends on the lithology of the area and the presence of fault zones. The rock mass network cut by faults of various widths influences the amplitude of tremor reaching the area’s surface. The analysis of the impact of the width of the fault zone was done for three alternatives.
Assessment of burned coal shale properties based on cyclic load
Authors: Grygierek Marcin , Kalisz Piotr , Pacześniowski Krzysztof , Pytlik Andrzej , Zięba Magdalena
Published: April 2018

Road surfaces that are subjected to cyclic loads generated by vehicle wheels must meet the requirements concerning the durability in the assumed period of use. The durability of the layered pavement construction systems depends on the value and frequency of the load as well as on the mechanical features of its individual layers. Layers of unbound, mechanically stabilized mixtures are a significant aspect of surfaces that are susceptible. Mixtures of this type can be applied both to the subgrade layers as well as to the bottom pavement layers, including the improved course. Considering the cyclic nature of the load on the surface of the entire system, mechanically stabilized layers are subject to continuous, but slow, densification during the period of use, which results in the formation of permanent deformations and so-called structural ruts. Post-mining waste is frequently used in road construction. which is the so-called burned shale that can be used for the bottom layers of the surface and layers of the improved subgrade (soil replacement). This material was the subject of the analysis. The evaluation was based mainly on the results of pilot studies covering cyclic loads of the layer/course made of the so-called red shale. The applied research method was aimed at preliminary assessment of its suitability for the assessment of the behaviour of the disintegrated medium under the conditions of test loads simulating the movement of vehicles.
Deformations of temporary wooden supports used to reduce building deflections in mining areas
Authors: Gromysz Krzysztof
Published: April 2018

Temporary supports, consisting of a stack of wooden elements and a hydraulic jack, are used in the process of removing deflections in buildings with one to three aboveground floors in mining areas. During uneven raising, the supports are loaded monotonically, unloaded and loaded cyclically. Laboratory tests were designed for the supports. For the investigated range of loads of 0 to 400 kN, under a growing load, a linear relationship exists between a load and the change in the stack length, which signifies that the deformations of wooden elements and displacements related to their mutual interactions increase proportionally. A seemingly higher stack stiffness is seen at the beginning of the unloading process and for cyclical loads, meaning that in this phase of loading, the material deformation of the wooden elements and the jack is responsible for changing the jack length in this load phase, with a negligible presence of mutual displacements of wooden elements. The support, after being unloaded, returns to the initial position and its permanent deformations are not observed. The stiffness of a temporary support decreases as the height of the stack of wooden elements increases.
Application of the digital image correlation method in the study of cohesive coarse soil deformations
Authors: Kogut Janusz P. , Tekieli Marcin
Published: April 2018

Non-contact video measurement methods are used to extend the capabilities of standard measurement systems, based on strain gauges or accelerometers. In most cases, they are able to provide more accurate information about the material or construction being tested than traditional sensors, while maintaining a high resolution and measurement stability. With the use of optical methods, it is possible to generate a full field of displacement on the surface of the test sample. The displacement value is the basic (primary) value determined using optical methods, and it is possible to determine the size of the derivative in the form of a sample deformation. This paper presents the application of a non-contact optical method to investigate the deformation of coarse soil material. For this type of soil, it is particularly difficult to obtain basic strength parameters. The use of a non-contact optical method, followed by a digital image correlation (DIC) study of the sample obtained during the tests, effectively completes the description of the behaviour of this type of material.
Geotechnical aspects of locating the Łagiewnicka Route on the area of the “White Seas” in Kraków
Authors: Zięba Jakub , Bazarnik Mirosława
Published: April 2018

The article presents the results of field studies and laboratory tests of the subsoil of the section of the „Łagiewnicka” route located on the area of so-called “White Seas” [1] in Kraków-Łagiewniki. The analysed samples come from the layer of anthropogenic soils being the result of the operation of the Solvay Sodium Plant in the 20th century. The results of the geotechnical and land-surveying studies served as the basis for developing a numerical model to determine the pressure on the walls of the planned tunnel and the horizontal thrust in the planned excavation. Besides, the study and test results were used to perform an analysis of the excavation’s stability and to check the impact of the sheet pile on land deformations near the John Paul II Centre in Kraków.
Linking results of key and supplementary comparisons of AC/DC voltage transfer references
Authors: Velychko Oleh
Published: April 2018

A regional key comparison (KC) COOMET.EM-K6.a and a supplementary comparison (SC) COOMET.EM-S1 of AC/DC voltage transfer references were conducted between participating laboratories from the Eurasian region. Measurements were made over the period 2004–2014. The results showed good agreement between all but one of the participating laboratories. The proposed procedure of linking results of key and SCs of regional metrology organization of AC/DC voltage transfer references is presented. Linking results is realized for COOMET.EM-K6.a and CCEM-K6.a KCs, and for COOMET.EM-K6.a KC and COOMET.EM-S1 SC.
Algorithms for classification of a single channel EMG signal for human-computer interaction
Authors: Lukyanchikov Andrei , Melnikov Alexei , Lukyanchikov Oleg
Published: April 2018

One of the most accurate and effective ways to control gestures is to control muscle activity, which occurs with any movement. Electromyography (EMG) is used to record such activity. This article compares SVM classification algorithms, perceptron, random trees and the method of density of probability in relation to the EMG signal. Arduino Leonardo with a single-channel Shield EMG is used to record the signal. The aim of this paper is to prove the possibility of creating a cheap and accessible biointerface based on EMG signal.
Soft clustering method for text mining, with an opportunity to attribute them to different semantic groups
Authors: Zhukov Dmitriy , Andrianova Elena , Otradnov Konstantin , Istratov Leonid
Published: April 2018

The work describes new soft clustering method for text mining, developed by the authors, with an opportunity to attribute them to different semantic groups. The work of this algorithm is based on usage of definition parameter, when deterimining clustering accuracy, which can be defined for texts of various subject areas either on basis of percolation properties of text clusters, or estimated theoretically based on the redundancy model for text messages. By the author’s assumption, proposed algorithm must have speed and accuracy for clustering of texts, depending on value of clustering accuracy parameter. The advantage of this algorithm is that no need to set an initial value of clusters.
Data traffic filtration of automated non-destructive testing based on an artificial neural network
Authors: Kosach Alisa , Kovshov Evgeny
Published: April 2018

The principle of constructing a universal software and hardware platform for the collection, processing and storage of data obtained as a result of non-destructive testing of products is considered. The platform also includes a neural network module for filtering data traffic, which has a wide potential for application: from image and multidimensional signal processing to data classification. The system of remote leakage control, built on the basis of a universal digital platform with artificial neural network, is described.
Online Inductance and Capacitance Identification Based on Variable Forgetting Factor Recursive Least-Squares Algorithm for Boost Converter
Authors: Chen Chen , Min Run , Tong Qiaoling , Tao Shifei , Lyu Dian , Li Linkai
Published: April 2018

The control performance of boost converter suffers from the variations of important component parameters, such as inductance and capacitance. In this paper, an online inductance and capacitance identification based on variable forgetting factor recursive least-squares (VFF-RLS) algorithm for boost converter is proposed. First, accurate inductance and capacitance identification models and the RLS algorithm are introduced. In order to balance the steady-state identification accuracy and parameter tracking ability, a forgetting factor control technique is investigated. By recovering system noise in the error signal of the algorithm, the value of forgetting factor is dynamically calculated. In addition, since the sampling rate is much lower than the existing identification methods, the proposed algorithm is practical for low-cost applications. Finally, the effectiveness of the proposed algorithm is verified by experiment. The experiment results show that the algorithm has good performance in tracking inductance and capacitance variations.
SLG(Single-Line-to-Ground) Fault Location in NUGS(Neutral Un-effectively Grounded System)
Authors: Zhang Wenhai , He Meimei , Ren Jie , Wen Yongke , Zhang Zheng , Pu Zhou , Zhang Rongjian
Published: April 2018

This paper reviews the SLG(Single-Line-to-Ground) fault location methods in NUGS(Neutral Un-effectively Grounded System), including ungrounded system, resonant grounded system and high-resistance grounded system which are widely used in Northern Europe and China. This type of fault is hard to detect and location because fault current is the sum of capacitance current of the system which is always small(about tens of amperes). The characteristics of SLG fault in NUGS and the fault location methods are introduced in the paper.
Efficient Voltage Regulation with Modified Hybrid SEPIC DC-DC-Converter
Authors: Ali Azam Khan Md. , Ali Choudhury Mohammad
Published: April 2018

Switch mode dc-dc converters are attractive for their small size, ease of control and efficient power conversion. Output voltage is regulated by duty cycle control of semiconductor switch of switch mode dc-dc converters. The voltage gain and efficiency of practical switching regulators deviate from ideal values at extreme duty cycles. Also, desired gain /attenuation is not achievable at high/low duty cycles. In applications where high gain or high attenuation of voltage is desired with acceptable energy conversion efficiency, hybrid dc-dc switching converters are used. Hybrid dc-dc converters are combination of voltage multiplier/division circuit with appropriate SMPS circuits. By incorporating voltage multiplier/division cell with conventional SEPIC converters, desired voltage gain (either very low or very high) may be achieved at acceptable energy conversion efficiency. In the present work with an aim to attain very high voltage gain by conventional SEPIC topologies, a new voltage multiplier cell consisting of multiple inductors and diodes is proposed.
Numerical Simulation of Internal Flow Field, Electromagnetic Field and Temperature Field in Deep-Water Motor
Authors: Zhang Qi , Li Zengliang , Yu Ran , Sun Zhaocheng , Zhang Le
Published: April 2018

In this paper, considering the heat exchange between the ends of stator&rotor and lubricating oil, the internal flow field model is established to analyse the flow state. The variation law of the pressure drops in the internal flow field and the friction loss of the rotor surface are specified. The operation characteristic of the motor and the variation law of the magnetic field loss are obtained through the analysis of motor magnetic field. Based on the results of internal flow field and magnetic field, the temperature distribution law of motor is obtained. Compared with the result of the temperature simulation in which only air gap path is considered, the stator temperature shows totally different distribution law, and the stator temperature increases from 32°C to 42°C. Compared with the result of the temperature simulation without considering heat source loss change, the maximum temperature of the motor decreases from 71°C to 49°C. The results show that the ends of stator&rotor and the variation of heat source loss can influence the temperature simulation results.
Study on Maneuvering Target On-axis Tracking Algorithm of Modified Current Statistical Model
Authors: Zhenkai Xiong , Fanying Li , Lei Zhang
Published: April 2018

Aiming at the model adaptability and the filter precision on the maneuvering target on-axis tracking, The paper put forward a filter algorithm based on modified current statistical model. The algorithm can enhance the model adaptability to the weak and non-maneuvering maneuvering target. The method uses Unscented Kalman Filter to obtain the importance density function of each particle, improves the Particle Filter estimation performance.By applying the proposed algorithm to the on-axis tracking system, the simulation results demonstrate that algorithm can effectively improve filter performance and tracking precision.
Preparation and Characterization of Pure Organic Dielectric Composites for Capacitors
Authors: Mao Xin , Lv Jinliang , Zhang Fangfang , Wu Bo , Yang Jie , Du Lirong , Tang Xianzhong
Published: April 2018

This work reports the excellent dielectric composites were prepared from polyimide (PI) and poly(vinylidene fluoride) (PVDF) via solution blending and thermal imidization or chemical imidization. The dielectric and thermal properties of the composites were studied. Results indicated that the dielectric properties of the composites synthesized by these two methods were enhanced through the introduction of PVDF, and the composites exhibited excellent thermal stability. Compared to the thermal imidization, the composites prepared by chemical imidization exhibited superior dielectric properties. This study demonstrated that the PI/PVDF composites were potential dielectric materials in the field of electronics.
A Novel Unscheduled Islanding Detection Method for Microgrid
Authors: Li Hui , Li Zhaohan , Guo Zhonghan , Lu Junwei
Published: April 2018

Microgrid with its intelligent and flexible control characteristics conform to the trend of sustainable development of electricity, and when the microgrid in the unplanned island state, the successful detection of the island is a prerequisite, energy storage inverter as the key equipment in the microgrid system, island protection is one of the necessary functions. In this paper, an improved islanding detection method based on active frequency drift and q-axis reactive power perturbation is proposed. The method has the advantages of faster detection speed and minor influence on power quality, which makes the energy storage inverter with better output power quality when it works on grid-connected state, and can be detected the islanding state quickly from grid-connected mode to islanded mode. Finally, the validity and superiority of the improved island detection method are verified by simulation experiments.
Study on a New Operational Mode of Economic Operation of Islanded Microgrids Using Electric Springs
Authors: Zhao Zhiyu , Wang Keyou , Li Guojie , Jiang Xiuchen , Zhang Yin
Published: April 2018

With the increasing penetration of intermittent renewable energy sources (RESs) into microgrids, the original operation mode of power generation determined by load demand faces severe challenges due to the uncertainties of the RESs power output. The electric springs(ESs), as an emerging technology has been verified to be effective in enabling load demand to follow power generation and stabilizing fluctuation of RESs output. This paper presents a new mode of economic operation for island microgrids including non-critical loads with embedded electric springs. Its connotation includes that i) the capacity of energy storage can be reduced through the interaction of the energy storage system (ESS) and the electric springs, ii) the electric springs reduce the stress of peak load regulation and operational cost and iii) the demand of microgrids system for ramping ability of generation units is reduced with the buffer of the electric springs. Numerical results show that the coordinated operation between electric springs and energy storage system of microgrids can bring down the investment cost for the ESS and short-term operational cost in the aspect of economic dispatch, reducing requirements for the capacity and ramp ability of the energy storage system in microgrids. Energy buffering can be achieved with lower cost and the load demand can follow power generation in the new operational mode of islanded microgrids using electric springs.
Hybrid Force and Position Control Strategy of Robonaut Performing Object Transfer Task
Authors: Chen Gang , Wang Yu-Qi , Jia Qing-Xuan , Cai Pei-Lin
Published: April 2018

This paper proposes a coordinated hybrid force/position control strategy of robonaut performing object transfer operation. Firstly, the constraint relationships between robonaut and object are presented. Base on them, the unified dynamic model of the robonaut and object is established to design the hybrid force/position control method. The movement, the internal force and the external constraint force of the object are considered as the control targets of the control system. Finally, a MATLAB simulation of the robonaut performing object transfer task verifies the correctness and effectiveness of the proposed method. The results show that all the targets can be control accurately by using the method proposed in this paper. The presented control method can control both internal and external forces while maintaining control accuracy, which is a common control strategy.
Integral Command Filtered Backstepping Control of a Flexible UAV
Authors: Han Ding , Yan Lin , Yan Guozheng , Wang Xiaoliang , Duan Dengping
Published: April 2018

Airships, as the significant UAV, have a need for greater autonomy in their new missions. Therefore, airship flight control systems require precise dynamic modeling, taking into account the effect of flexibility and the interaction with aerodynamic forces. This research effort develops an efficient modeling of the autonomous flexible airship. The formalisation used is based on the Lagrange method. The resulting model includes the rigid body motion, the elastic deformation, and the coupling between them. Based on the precise flexible dynamic model, a novel backstepping nonlinear controller with integral action is proposed for motion control systems. The resulting feedback controller is able to adapt to actuator performance limitations, such as limitations in magnitude and rate of change of rudder, than conventional backstepping controller without integral action. With the deformation considered, the presented controller could resist the flexible uncertainty effect, and the system’s trajectory tracking ability is significantly improved. The approach guarantees exponential stability of a compensated tracking error in the sense of Lyapunov.
Modeling and Analysis of a Closed-Loop System for High-Q MEMS Accelerometer Sensor
Authors: Wang Yalin , Yang Yongjun
Published: April 2018

High-Q sensing element is desirable for high performance while makes the loop control a great challenge. This paper presents a closed-loop system for high-Q capacitive MEMS accelerometer which has achieved loop control effectively. The proportional-derivative(PD)control is developed in the system to improve the system stability. In addition, pulse width modulation (PWM) electrostatic force feedback is designed in the loop to overcome the nonlinearity. Furthermore, a sigma-delta (ΣΔ) modulator with noise shaping is built to realize digital output. System model is built in Matlab/Simulink. The simulation results indicate that equivalent Q value is reduced to 1.5 to ensure stability and responsiveness of the system. The effective number of bits of system output is 14.7 bits. The system nonlinearity is less than 5‰. The equivalent linear model including main noise factors is built, and then a complete theory of noise and linearity analysis is established to contribute to common MEMS accelerometer research.
Simulation on Spacecraft Formation Flight and Formation Reconfiguration
Authors: Ye Yan Chao Li , Yang Yue-neng
Published: April 2018

Spacecraft formation flight refers to two or more spacecraft according to a certain formation or arrangement of flight, it has important application value for deep spatial exploration, spatial science experiment, ground investigation and military and so. This paper studies the spacecraft formation flight design and formation reconfiguration based on STK. Firstly, the Clohessy-Wiltshire (CW) equation is used to describe the relative motion of the near-circular orbit and deduce the relative orbital dynamics model. Then, based on the dynamic method of the CW equation, the spatial circular formation is designed and the STK is applied to simulate it. Finally, based on the above formation, a simple multi-impulse formation reconfiguration is performed and the simulation test is verified by STK. The simulation results show that the absolute error of orbital elements of the spacecraft is calculated by the relative orbital dynamics model is less than 10-5, and the expected formation can be completed under the condition of two-body environment, and the feasibility of simple multi-pulse formation reconfiguration is proved successfully.
Automobile safety technology and its improvement
Authors: Wang Xiao-Yang , Jiang Yi-Hang , Li Ren-Bo , Chen Ming-Zhang
Published: April 2018

With the development of society, and the sharp increase in car sales, traffic accidents have become increasingly frequent and serious .At the same time, with the rapid development of science and technology, automotive technology has also been rapidly improved, automotive safety technology gradually involved in all aspects of the car. This paper introduces the main automotive safety technology at present, proposes a kind of airbag system, and describes its specific working methods.
Simultaneous Localization and Mapping of Mobile Robot Based on Improved RBPF
Authors: Zhang Jinging , Ruan Xiaogang , Dong Pengfei , Zhou Jing
Published: April 2018

The traditional SLAM based on RBPF has the problem of constructing high-precision map which requires large amounts of particles to make the calculation complexity and the phenomenon of particle depletion caused by particle degradation. Aiming at these problems, an improved RBPF particle filter based on adaptive bacterial foraging optimization algorithm and adaptive resampling is proposed for mobile robot SLAM problem. Firstly, the introduction of adaptive bacterial foraging algorithm to RBPF making the distribution of particles before resampling closer to the real situation. Then use the adaptive resampling method makes the newly generated particles closer to the real movement, thereby increasing the robot position estimation accuracy and map creation accuracy. The experimental results show that this method can improve the practicability of the system, reduce the computational complexity, improve the operation speed and get more effective particles while guaranteeing the accuracy of the grid map.
A Dynamics Controller Design Method for Car-like Mobile Robot Formation Control
Authors: Wang Baofang , Qian Chen , Chen Qingwei
Published: April 2018

A dynamics controller design method based on characteristic model is proposed for the formation control problem of car-like mobile robots. Only kinematics controller is not enough for some cases such as the environment is rugged, and the dynamics parameters of the robot are time-varying. Simulation results show that the proposed method can improve the responding speed of the mobile robots and maintain high formation accuracy. First, we obtain the kinematic error state equations according to the leader-follower method. A kinematics controller is designed and the stability is proved by Lyapunov theory. Then the characteristic model of the dynamics inner loop is established. A sliding mode controller is designed based on the second order discrete model, and the stability of the closed-loop system is analyzed. Finally, simulations are designed in MATLAB and Microsoft Robotics Developer Studio 4 (MRDS) to verify the effectiveness of the proposed method.
The Square Root UKF-SLAM Algorithm Based on the Smallest Proportion of Skewness in Single Line Sampling
Authors: Chen MengYuan , Qin GuoWei , Xu Tong
Published: April 2018

In view of the distortion in the filter gain matrix calculation as well as the high computational complexity and the nonlocal effect of symmetric sampling that exists in the UKF-SLAM algorithm, the square root UKF-SLAM algorithm based on the smallest proportion of skewness in single line sampling was proposed. According to the mended algorithm, the square root of covariance matrix is brought into iteration operation instead of covariance matrix, moreover, the smallest proportion of skewness in single line sampling is utilized for the optimization of sampling strategy. The results of simulation show that the algorithm can effectively improve the position accuracy in robot as well as the estimation accuracy of feature map. Furthermore, the computational complexity is reduced and the algorithm stability is improved.
Novel Design of a Biaxial and Four-Wheeled Robot Capable of Steering
Authors: Lan Guiping , Wang Yujun , Fang Can , Yi Min
Published: April 2018

The paper presents a biaxial and four-wheeled robot, mainly composed of two axle, two circular wheels and two three-leaved wheels. By analyzing the difference between the velocity of the circular wheel and three-leaved wheel in same axle, the steering principle of the difference velocity is proved. The three-leaved wheels are installed by a complementary phase method to ensure the stability of the robot walking. Through the steering principle, the control method of robot’s forward, backward, turn left and turn right is designed. A large number of experimental results show that the robot has the characteristics of high steering efficiency, simple mechanical structure and easy to control.
Design and Implementation of Image Capture Sentry Gun Robot
Authors: Kashif Muhammad , Arslan Muhammad , Chakma Rocky , Chakma Rocky , Banoori Farhad , Mamun Abdullah Al , Chakma Ganantu Lal
Published: April 2018

This paper is about the development and design of semi-autonomous sentry robot using aurdino controller. There is a global issue of that everyone wants to secure themselves from different sorts of danger and to navigate their surroundings. This robot called Sentry Gun, because it consists of a Gun mounted on a stand and an operator can also operate it from a secure location. Sentry Gun is based on latest research, it uses high resolution camera to scan the target area and movement can be detected by using software i.e processing .org As compare to humans it can perform far better while operating in autonomous mode in red zones, it will bring a significant fall in the death toll, if installed outside every check post, law enforcement agencies and borders, to stop illegal intrusions.
Ketones, omega-3 fatty acids and the Yin-Yang balance in the brain: insights from infant development and Alzheimer’s disease, and implications for human brain evolution
Authors: Cunnane Stephen C.
Published: April 2018

Optimal brain performance is intimately linked to the brain’s Yin and the Yang − the balance between its structure and its energy metabolism. This relationship is clearly exemplified in infant brain development and in Alzheimer’s disease, and probably also applies to human brain evolution. In these examples,redundant pathwayshelp achieve this important balance. For instance, the key structural lipid for the brain, docosahexaenoic acid (DHA), is supplied to the infant brain from at last three overlapping sources: (i) milk; (ii) infant’s own fat stores and (iii) by some endogenous synthesis from α-linolenic acid (ALA) or eicosapentaenoic acid (EPA). On the energy side, glucose is normally the brain’s main fuel but under conditions of prolonged starvation, it can be almost totally replaced by the ketone bodies, acetoacetate and β-hydroxybutyrate. When ketones are present in the blood they spare glucose uptake by the brain because they are actually the brain’s preferred fuel and are essential for normal infant brain development. The redundant sources of ketones are long chain fatty acids (including the relatively ketogenic ALA) in infant stores, and medium chain triglycerides (MCT) in milk. Besides infancy, nowhere is the strain on the brain’s balance between yin and yang more apparent than in Alzheimer’s disease (AD). One of the reasons why attempts to treat AD have largely failed could well be because chronically inadequate glucose supply to some areas of the brain on the order of 10% is present in people at risk of AD long before cognitive decline begins. However, brain ketone uptake is still normal even in moderately advanced AD. Hence, treatments that ignore the brain energy (glucose) deficit in AD would be predicted to fail, but treatments that attempt to rescue brain fuel availabilityviaketones would be predicted to have a better chance of succeeding. By analogy to ketones sparing glucose for brain energy metabolism, perhaps ALA or EPA entering the brain can help spare (conserve) DHA for its structural role. If so, it would not necessarily be futile to transport ALA and EPA into the brain just to β-oxidize the majority afterwards; DHA sparing as well as ketone production could be important beneficiaries.