bluuebunny/crossref_metadata_2025 huggingface dataset:
Full-Squat as a Determinant of Performance in CrossFit
Authors: Martínez-Gómez Rafael , Valenzuela Pedro L. , Barranco-Gil David , Moral-González Susana , García-González Adela , Lucia Alejandro
Published: July 2019

This study analyzed the relationship between CrossFit performance and power and strength variables measured in the full-squat exercise. Twenty male trained subjects (33±7 years) performed an incremental load full-squat test for assessment of the 1-repetition maximum (1RM) and the mean (Pmean) and peak (Ppeak) power. Performance in 5 different Workouts of the Day (WODs) was measured on different days, and overall CrossFit performance was determined as the sum of the scores obtained in these WODs. Athletes were then assigned to a high (HP) or low (LP) performance group based on the median score for overall performance. Correlation analysis between squat variables and performance was performed and between-group differences were assessed. Moderate to strong (r=0.47–0.69, p<0.05) positive correlations were found between squat variables and performance in the different WODs. Overall CrossFit performance was strongly and positively associated with absolute (r=0.62, p=0.01) and relative 1RM (r=0.65, p=0.07), and relative Pmean (r=0.56, p=0.02) and Ppeak (r=0.53, p=0.03). Large differences (effect sizes ranging 1.1–1.7, all p<0.05) were observed between HP and LP for absolute and relative 1RM, relative Pmean, and absolute and relative Ppeak. In summary, strength and power indexes measured in a squat test are positively associated with CrossFit performance.
Large-Scale Synthesis of Aniline Trimers in Different Oxidation States
Authors: Yepez Gerardo , Poyil Anurag Noonikara , Bugarin Alejandro
Published: July 2019

Polyanilines are an important class of organic compounds, due to their utility in a large variety of applications. In contrast, oligo­anilines have been employed far more sporadically, in large part reflecting an absence of refined synthetic approaches. Herein, we report, for the first time, a relatively large-scale strategy to generate highly pure aniline trimers at different oxidation states with excellent yields (90–97%).
Protease-Activated Receptors 1 and 3 are Differentially Expressed on Human Monocyte Subsets and are Upregulated by Lipopolysaccharide Ex Vivo and In Vivo
Authors: Thaler Barbara , Hohensinner Philipp J. , Baumgartner Johanna , Haider Patrick , Krychtiuk Konstantin A. , Schörgenhofer Christian , Jilma Bernd , Hell Lena , Fischer Michael B. , Huber Kurt , Hengstenberg Christian , Speidl Walter S. , Wojta Johann
Published: July 2019

Monocytes are activated in inflammatory conditions via a variety of cytokine receptors as well as in a procoagulatory setting through thrombin, acting upon protease-activated receptors (PARs). This study investigated the expression pattern of PAR1 and PAR3 on human monocyte subsets. Furthermore, a possible regulation of the expression of PAR1 and PAR3 in these cells by inflammatory activation were studied. CD16+ monocytes showed significantly higher levels of PAR1 and PAR3 as compared with CD16− monocytes. Ex vivo treatment of whole blood with lipopolysaccharide (LPS) increased PAR1 and PAR3 messenger ribonucleic acid (mRNA) in human monocytes. In addition, increase of PAR1 was seen in all three subsets upon LPS treatment, whereas PAR3 increased significantly only in CD16− monocytes and nonclassical CD16+ monocytes. Protein levels of PAR1 and PAR3 significantly increased on monocytes in vivo in human endotoxemia 1 hour after LPS infusion. PAR1 increased significantly in CD16− monocytes and nonclassical CD16+ monocytes. In this in vivo model, PAR3 was also significantly elevated in CD16− monocytes and increased slightly albeit not significantly in CD16+ monocytes. Endotoxemia increased plasminogen activator inhibitor-1 (PAI-1) and tissue factor (TF) expression in monocytes in humans. Pretreatment of healthy volunteers with the PAR1 antagonist vorapaxar blocked the increase in PAI-1 but not the increase in TF. We here provide new evidence for a critical role for monocytes as cellular mediators that contribute to the activation of coagulation in diseases characterized by an inflammatory state.
Urinary Ascites and Transient Intestinal Obstruction in a Preterm Infant: An Interesting Case of Posterior Urethral Valve
Authors: Mani S. , Kupferman F. , Kumar K. , Hazra S. , Sokal M. , Jean-Baptiste D. , Kim R.
Published: July 2019

Posterior urethral valve (PUV) is the most common congenital cause of bladder outflow obstruction in male neonates. We report a preterm neonate with PUV who presented as nonimmune fetal hydrops with intestinal obstruction in the antenatal period. The mother of our patient is a 33-year-old woman who started her prenatal care at our hospital at 30 weeks' gestation. Her sonogram done at 32 weeks in our hospital revealed fetal hydrops. It showed polyhydramnios, mild pyelectasis of right kidney, normal left kidney, and fetal ascites. Amniocentesis revealed bile stained amniotic fluid. Ultrasound during the procedure showed dilated fetal bowel loops with increased echoes. Following delivery at 32 weeks postnatal exam showed ascites with absence of skin edema, pleural, or pericardial effusion. The abdominal sonogram showed distended urinary bladder and bilateral hydroureteronephrosis. Bladder catheterization was done which relieved the bladder outlet obstruction. Voiding cystourethrogram was done later which confirmed PUV and bilateral grade 5 vesicoureteral reflux. The formation of urinary ascites in PUV serves as a pop-off mechanism to relieve the intravesical and intrarenal pressure. When this happens by mechanisms other than bladder rupture, it can lead on to transient intestinal obstruction and hepatic synthetic defects.
Potential pitfalls of the early-time dynamics in two-dimensional electronic spectroscopy
Authors: Paleček David , Edlund Petra , Gustavsson Emil , Westenhoff Sebastian , Zigmantas Donatas
Published: July 2019

Two-dimensional electronic spectroscopy, and especially the polarization-controlled version of it, is the cutting edge technique for disentangling various types of coherences in molecules and molecular aggregates. In order to evaluate the electronic coherences, which often decay on a 100 fs time scale, the early population times have to be included in the analysis. However, signals in this region are typically plagued by several artifacts, especially in the unavoidable pulse overlap region. In this paper, we show that, in the case of polarization-controlled two-dimensional spectroscopy experiment, the early-time dynamics can be dominated by the “incorrect” pulse ordering signals. These signals can affect kinetics at positive times well beyond the pulse overlap region, especially when the “correct” pulse ordering signals are much weaker. Moreover, the “incorrect” pulse ordering contributions are oscillatory and overlap with the spectral signatures of energy transfer, which may lead to misinterpretation of “incorrect” pulse ordering signals for fast-decaying coherences.
Parametric study of a high amplitude electromagnetic pulse driven by an intense laser
Authors: Aktan E. , Ahmed H. , Aurand B. , Cerchez M. , Poyé A. , Hadjisolomou P. , Borghesi M. , Kar S. , Willi O. , Prasad R.
Published: July 2019

An investigation of the electromagnetic (EM) pulse produced by high intensity laser-solid interactions has been carried out by employing the proton probing technique. Laser parameters including energy, pulse duration, and intensity were varied to investigate the influence on the EM pulse amplitude. The data reveal that the amplitude of the EM pulse depends on the incident laser energy and the pulse duration. The optimum pulse length for a given laser energy is found to be close to 100 fs. The net charge associated with the traveling EM pulse has been found to be dependent on the laser intensity, in a good agreement with a semiempirical model. The understanding of the EM pulse is important for the postacceleration of laser driven proton beams.
Fabrication of high-strength carbon nanotube bundles using iron oxides co-assisted chemical vapor deposition
Authors: Fujimori Toshihiko , Matsuo Kanade , Masuda Hideki , Kikuchi Yu , Otsuka Jun , Tanioka Daisuke , Hikata Takeshi , Okubo Soichiro , Ito Yoshikazu , Fujita Jun-ichi
Published: July 2019

We report the fabrication of centimeter-long, defect-free, and parallel-aligned single-wall carbon nanotubes (SWCNTs) using a laboratory-designed two-step catalytic chemical vapor deposition method. Our in situ mass spectral analysis reveals that the initial stainless-derived iron oxide block decomposes methane into acetylene and ethylene, subsequently promoting the growth of high-purity SWCNTs on the second pigment-derived iron oxide fine powders dispersed on the Si/SiO2 substrate. Raman spectral imaging shows the negligible defect-induced D-band in the resulting sample, indicating the highly crystalline structure of SWCNTs. By using a gas-flow-type mechanical test system, an SWCNT bundle containing 20 components of individual SWCNTs exhibits the tensile strength over 50 GPa. Since the catalysts used in this study are widely available on the industrial scale, our iron oxide coassisted method will lead to the scalable production of high-strength SWCNT bundles.
Quantum transport in the presence of contact vibrations
Authors: Peskin Uri
Published: July 2019

We explore the transport of fermions through a quantum conductor in the presence of contact vibrations. The latter are coupled to charge transfer between the fermion reservoirs and the conductor but remain inert to the charging state of the conductor itself. We derive explicit expressions for charge transfer rates into and out of the conductor which extend the scope of rate theories of inelastic transport to the presence of contact vibrations. Implementing the theory to a simple model with a uniform vibronic coupling at different contact orbitals, we demonstrate and analyze the effect of such vibrations on the charge current. Asymmetry between contact vibrations at the two reservoirs is shown to induce a pronounced current rectification, especially in the limit of floppy (low frequencies) contacts. At high frequencies, vibrational quantization is shown to suppress the effect, in accord with the increasing contact rigidity. This quantum result requires corrections beyond the classical theory of charge hopping.
Surface modification of PVA thin film by nonthermal atmospheric pressure plasma for antifogging property
Authors: Paneru Ramhari , Lamichhane Pradeep , Chandra Adhikari Bishwa , Ki Se Hoon , Choi Jinsung , Kwon Jae Sung , Choi Eun Ha
Published: July 2019

In this work, a polyvinyl alcohol (PVA) thin film was modified by exposure to a dielectric barrier discharge argon plasma. The plasma was generated by a sinusoidal power supply with discharge voltage of 4.75 kV (rms), and frequency of 30 kHz at duty cycle 6.13%. The effect of the plasma on the PVA thin film was investigated by analyzing the contact angle, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and UV–visible spectroscopy. After the plasma treatment, the contact angle was found to be decrease from 29.6 ± 0.4° to 14.5 ± 0.2°, which implied that the surface property had changed to a hydrophilic state caused by an increase in the surface roughness and introduction of oxygen, including a polar carbonyl group. It was found that the plasma-treated hydrophilic PVA thin film exhibited excellent antifogging and highly transparent characteristics, making it an appropriate material for food packaging and green houses.
Below-bandgap photoluminescence from GaAs substrates induced by pre-MBE-growth treatments
Authors: Roca Ronel Christian , Fukui Kosei , Mizuno Hiroto , Suzuki Mikihito , Kamiya Itaru
Published: July 2019

We report the observation of below-GaAs-bandgap photoluminescence (PL) emission from semi-insulating GaAs substrates subjected to thermal annealing during the standard pre-MBE-growth processes. The below-GaAs-bandgap luminescence from defects were investigated using a combination of PL techniques including below-gap-excitation (BGE) and backside illuminated (BI) PL. Using BGE and BI PL, defects deep within the substrates were probed, and their spatial positions along the sample were analyzed. A PL peak at 1000 nm was observed after pre-bake annealing at 300°C, and further peaks at 905, 940 and 1150 nm were found after oxide desorption annealing at 600°C. These are attributed to the Ga-vacancy related defect, Ga-vacancy-complex defect, As-vacancy defect, and InGaAs states, respectively. This is the first report of the formation of such optically-active defects after annealing of GaAs at moderate temperature ranges (≤600°C), providing guidelines to distinguish desired electronic states for device applications from those that arise from defects which often confuse, and also degrade the device performances.
The interactions between thermodynamic anomalies
Authors: Fijan Domagoj , Wilson Mark
Published: July 2019

The origin of and interactions between key thermodynamic anomalies are derived and analyzed, as are the interactions with the stability (or cavitation) limits. The conditions for interaction are derived from the underlying thermodynamic relations rather than using the more-commonly applied Taylor expansion method. As a result, we derive a general set of equations that govern the interactions between different lines of thermodynamic anomalies using standard manipulation of thermodynamic equations. The validity of the derivations is investigated by comparing them to numerical simulation data and previous Taylor expansion-based results. Simulations are performed using a modified Stillinger-Weber potential in which the balance of the two- and three-body interactions is varied and which serves to highlight the relationships between the various anomalies. The deeply supercooled regime is explored by employing replica exchange methods. The behavior of the anomalies is considered in terms of previously constructed thermodynamic “scenarios.” Based on the newly uncovered interaction schemes, we propose a classification strategy for the thermodynamic anomalies (as first- or second-order) which could be extended to additional related anomalies.
Cross-sectional hyperspectral imaging of proton implanted diamond
Authors: Turaga Shuvan Prashant , Jin Huining , Teo Ee Jin , Bettiol Andrew A.
Published: July 2019

Cross-sectional Raman/photoluminescence hyperspectral imaging was employed to study the formation and annealing behavior of optical centers in diamond, which was implanted by a focused 2 MeV proton beam. The resulting compact implantation profiles, together with the submicron spatial resolution of the hyperspectral imaging technique, produced detailed distributions of the nitrogen-vacancy centers and the TR12 center. In addition, cluster analysis was used to identify a split in the implantation end of range into two subregions, each with its own characteristic emission spectrum centered at 543 nm and 552 nm. We demonstrate that our analysis methodology on the hyperspectral dataset, paired with the use of focused beam implantation, provides a renewed understanding of defect formation and lattice damage in ion-implanted single crystal diamond.
In-situ investigation on the crystallization property and microstructure evolution induced by thermal annealing and electron beam irradiation of titanium antimony thin film
Authors: Wu Weihua , Shen Bo , Zhai Jiwei , Song Sannian , Song Zhitang
Published: July 2019

The crystallization properties of tellurium-free Ti30Sb70 thin films were examined by in situ electrical resistance measurements. The amorphous-to-polycrystalline transformation and microstructure evolution of the Ti30Sb70 material induced by thermal annealing and electron beam irradiation were detected by transmission electron microscopy. The crystallized Ti30Sb70 thin film under the effect of thermal heating and electron beam exhibited nanoscale grains with a homogeneous distribution. The crystalline phase can be indexed as a rhombohedral Sb structure and the crystalline grains were surrounded by the amorphous phase. The Ti element may exist in the amorphous state and can be considered to destroy the long-range order lattice of Sb crystal grains. The unique structure contributed to the improvement of thermal stability and localization of atom diffusion in a nanoscale during the reversible phase transition process.
Albinism in Dasyurus species – a collation of historical and modern records
Authors: Dunlop Judy , Peacock David , Moore Harry , Cowan Mitchell
Published: July 2019

A new record of an albino marsupial, the northern quoll (Dasyurus hallucatus), is described and placed in the context of 10 records since 1874 from all four Australian quoll species. Of the 10 previous records, one was D. hallucatus, seven are likely to be D. viverrinus, one D. maculatus and one unknown. The recent record comprises the live capture of a healthy adult female northern quoll from the Pilbara region of Western Australia. Despite the rarity and likely deleterious nature of the albino condition, this animal appeared to be in good health, carrying eight pouch young, and was released at location of capture following tissue sampling for DNA analysis.
The dynamic switch mechanism that leads to activation of LRRK2 is embedded in the DFGψ motif in the kinase domain
Authors: Schmidt Sven H. , Knape Matthias J. , Boassa Daniela , Mumdey Natascha , Kornev Alexandr P. , Ellisman Mark H. , Taylor Susan S. , Herberg Friedrich W.
Published: July 2019

Significance

Little is known about the regulation of Leucine-rich repeat kinase 2 (LRRK2) associated with familial Parkinson’s disease (PD). To test whether the kinase domain drives LRRK2 activation, we applied the spine concept that describes the core architecture of every protein kinase. We discovered that mutation of Y2018, a regulatory spine residue, to Phe in the DFGψ motif created a hyperactive kinase similar to the PD-associated mutation G2019S. The hydroxyl moiety of Y2018 thus serves as a “brake,” stabilizing the inactive conformation; simply removing it destroys a key inhibitory hydrogen-bonding node. These data reveal an LRRK2-specific regulatory mechanism, confirming that the kinase domain functions as a classical kinase that controls overall conformational dynamics in full-length LRRK2 and drives therapeutic strategies.
A simple variant selection in stress-driven martensitic transformation
Authors: Yue Binbin , Hong Fang , Hirao Naohisa , Vasin Roman , Wenk Hans-Rudolf , Chen Bin , Mao Ho-Kwang
Published: July 2019

Significance

Variant selection plays an important role during martensitic transformations in both metals and oxides. Due to its great effects on the crystallographic texture, it has received a great deal of attention in fields of physics, material science, and even Earth science. Previously, most studies focused on transitions in metals induced by temperature. Here, we investigate more complex oxides structures during the pressure/stress-driven martensitic transformation and find a very simple variant selection in cubic/orthorhombic Mn
2
O
3
. The high-pressure orthorhombic phase inherits texture from the low-pressure cubic phase. Only one of the six cubic {110} planes becomes the orthorhombic (100) plane: the one perpendicular to the compression direction. This will become a reference to demonstrate the variant selection behavior under high pressure.
dom and datives in Basque
Authors: Odria Ane
Published: July 2019

This paper analyzes the syntax ofdomand causee, experiencer, goal and possessor datives in Basque. It presents novel criteria distinguishing their categorical status: the possibility (i) to license Depictive Secondary Predication (DSP) and (ii) to appear as non-agreeing in contexts affected by thePerson Case Constraint(PCC). It argues that, contrary to the rest of the datives, goals are generated as PPs, since they are unable to license DSP, but able to occur as non-agreeing in PCC-affected contexts. Besides, despite exhibiting the same categorical status as causee, experiencer and possessor datives, it claims thatdomobjects are syntactically identical to canonical absolutives, as they show the same configurational as well as Case licensing pattern, which is based onv-Agree.
A xenon collisional-radiative model applicable to electric propulsion
devices: II. Kinetics of the 6s, 6p, and
5d states of atoms and ions in Hall
thrusters
Authors: Zhu Xi-Ming , Wang Yan-Fei , Wang Yang , Yu Da-Ren , Zatsarinny Oleg , Bartschat Klaus , Tsankov Tsanko Vaskov , Czarnetzki Uwe
Published: July 2019

Electric propulsion devices of using xenon propellant are nowadays widely adopted
for the space missions. A collisional-radiative (CR) model of xenon needs to be
developed to understand the kinetic mechanisms of the excited and energetic
species in these devices and also to support their optical diagnostics.
Previously, due to limitations in the fundamental cross section data, Xe CR
models focused on the atomic species; the ionic species, which also play
important roles for the thrusters, were not studied in detail. In our previous
paper, a fully relativistic Dirac B-spline
R-matrix method was applied to calculate the relevant cross
sections for electron collisions with the Xe+ ion. Based on
these data, a comprehensive CR model—with the kinetics of metastable and
excited levels of both Xe and Xe+ included—could be built.
The calculated density distributions of atomic and ionic levels are examined by
optical measurements in Hall thrusters in all of the four typical regions
(near-anode-, ionization-, acceleration-, and plume-region). The special kinetic
behaviors of the excited species are analyzed, and a set of rate coefficient
data used for the Xe CR model is also provided.
Improving the efficiency of power transformers insulation by modifying the dielectric paper with bacterial cellulose
Authors: Zhuravleva N M , Reznik A S , Kiesewetter D V , Stolpner A M , Smirnova E G , Khripunov A K
Published: July 2019

The electrophysical characteristics of experimental types of electrical insulating paper modified by bacterial cellulose made of nano-gel film Komagataeibacter xylinus, disintegrated in various ways, were studied. The advantage of composites over traditional electrical insulating paper made of pine cellulose is shown in terms of electrical and mechanical strength, sorption activity and heat resistance. The efficiency of using an industrial blender to grind bacterial cellulose has been confirmed, which significantly reduces the time of its high-quality grinding.
Structure, optical properties and resistance to laser radiation of thin barium disilicide films grown on silicon
Authors: Galkin N G , Galkin K N , Dubov V L , Fomin D V , Pyachin C A
Published: July 2019

Polycrystalline and oriented films of barium disilicide (BaSi2) with a thickness of up to 100 nm were formed on silicon (111) substrates by high-temperature (800 ° C) solid-phase (single-stage and two-stage) annealing. The single phase of barium disilicide films and their semiconductor nature have been proven to be below 1.25 eV according to X-ray and optical spectroscopic methods. Two preferential orientations of the BaSi2 crystallites were detected and their orientation was determined in the films formed by two-stage annealing. According to the calculations of the parameters of the crystal structure of BaSi2 films, a compression of the unit cell volume from 2.7% to 5.13% was found, depending on the cooling time to room temperature. The stability of the films to laser radiation was studied by registering the Raman spectra with a variable power of laser radiation. The maximum power density of the laser beam (3⋅109 W/m2), which does not lead to the beginning of the destruction of these films, was
determined.
Intelligent processing of acoustic emission data based on cluster analysis
Authors: Melnikov B F , Averin P I , Melnikova E A
Published: July 2019

In this paper, we propose to examine the neural network approach to the problem of calculating the characteristics of the deformation and fracture of metals by transforming the fuzzy clustering of pulses of acoustic emission. To solve the problem of division the metal samples into two classes (deformed and non-deformed) we separated signals from the samples using two algorithms, i.e. fuzzy clustering and neural network. 2 clusters were always formed corresponding to 2 types of signals. The error of the neural network tests was within 5%. Thus, by this approach one can achieve sub-pixel sampling of acoustic data on clusters and neural network learning algorithm for the automatic calculation of the characteristics of metals.
Machine learning and the Schrödinger equation
Authors: Pavlov A V , Serdyuk J A , Ustinov A B
Published: July 2019

In this research several methods of machine learning (ML), such as decision trees and linear regression were used to predict ground-state energy (GSE) of an electron in a potential well. Analysis has been done for various types of the potentials: ones with exact solution as well as ones with only numerical one. It was shown that some methods can map the analytical solution and predict GSE with chemical accuracy along with ability to find GSE for systems which does not have analytical solutions. To increase the accuracy and performance of the ML algorithms we proposed several methods of data preprocessing.
U-Net adaptation for multiple instance learning
Authors: Kots M V , Chukanov V S
Published: July 2019

Multiple instance learning (MIL) is a weakly supervised learning method where a single label is assigned to a group of instances. Recent advancement in neural networks makes it possible to achieve great results but the training requires many annotated examples which can be difficult to obtain. In case of medical imaging, such a method can theoretically provide voxel-level annotations basing on the image-level annotations. More precisely, taking a training dataset where each image is given with a label indicating a presence of a region of interest (ROI), the model can be trained to produce voxel labels of the object. We propose a modification of the U-Net architecture for image segmentation that can be trained on weakly labeled datasets and solves the MIL problem. The U-Net architecture is famous for being able to train on small number of samples which can further improve benefits of MIL approach. In this paper we also present results of experiments on synthetic data with investigation of stability to noise and medical images. Experimental results prove that suggested modifications improve the noise stability of the weakly supervised method.
Automatic detection of objects on star sky images by using the convolutional neural network
Authors: Bobrovsky A I , Galeeva M A , Morozov A V , Pavlov V A , Tsytsulin A K
Published: July 2019

The automatic detection methods of mobile objects on moving star background in the presence of high-speed image blurring are considered. The approach based on convolutional neural network YOLO v2 for detection and classification of two kinds of objects images is analysed. Estimations of detection accuracy and speed for the approach are based on convolutional neural network of a simplified structure, indicating further prospects for use of such networks.
The propagation of electromagnetic waves in ferrite-dielectric structure with metal shield
Authors: Cherepanov A S , Sochava A A , Bogachev S V
Published: July 2019

The paper deals with the problem of wave propagation in a rectangular waveguide containing a three-layer ferrite-dielectric-ferrite (FDF) structure located near a metal shield. This FDF structure can be used to create low-cost phased array antennas with simple electrical control of the beam position. However, the calculation of the open FDF structure encounters great difficulties. Placing the FDF structure in a rectangular waveguide allows us to obtain a strict solution for same waveguide wave modes including main mode, which have no dependence of the fields on the coordinate directed along the magnetizing field. This is the main mode of the FDF structure, which determines the general properties of the phased array. It is shown that the obtained relations describe the modes of the open FDF waveguide with high accuracy. The dependences of the mode propagation constants on the magnetizing field have been calculated, the structure of the electromagnetic field for the main and some higher order modes has been found, and the optimal parameters of the structure, which provide maximal controllability by magnetizing field, have been determined.
Error estimation of discrete formation method for optimal FTN signals
Authors: Ovsyannikova A S , Lavrenyuk I I , Makarov S B , Wei X
Published: July 2019

One of the branches of Faster than Nyquist (FTN) signaling providing transmission at the rate higher than “Nyquist limit” with insignificant energy losses includes optimal FTN pulses. These pulses have controllable level of intersymbol interference (ISI) and given time and spectral parameters. The efficiency of practical usage of these pulses depends on the errors of discrete formation method. In this work a guidance for estimating the minimum number of samples needed to meet the requirements for spectral and energy characteristics of optimal FTN signals is proposed. Simulation modeling and experiments with the help of vector signal generator have been held. It was found that to form optimal FTN pulse with duration Ts=2T not more than 16 samples are needed. In this case, energy losses relatively to continuous optimal FTN pulse are about 0.2 dB.
Characterisation of a near-infrared (NIR) fluorescence imaging systems intended for hybrid gamma-NIR fluorescence image guided surgery
Authors: Almarhaby A.M. , Lees J.E. , Bugby S.L. , Alqahtani M.S. , Jambi L.K. , McKnight W.R. , Perkins A.C.
Published: July 2019

A novel hand-held hybrid optical-gamma camera (HGC) has previously been described that is capable of displaying co-aligned images from both modalities in a single imaging system. Here, a dedicated NIR imaging system for NIR fluorescence surgical guidance has been developed for combination with the HGC . This work has evaluated the performance of two NIR fluorescence imaging systems using phantom studies, various fluorophores and various experimental configurations. The threshold detectable concentration of ICG and 800CW dyes were investigated for both systems. Bespoke lymph node phantoms simulating metastases and tissue-like layers were constructed to evaluate the detection capability. ICG could be detected at a minimum concentration of 1 μM for each camera. The lower thresholds for 800CW were 10−2and 10−3μM for the modified and NIR cameras, respectively. Both cameras were unable to detect small-sized targets within a 3 mm depth, but were able to identify larger targets as deep as 7 mm. Further improvements are required to optimise the NIR-fluorescence systems for subsequent combination with the HGC to undertake dual gamma-NIR fluorescence intraoperative imaging.
Pre-charging Characteristics Analysis and Control Strategy of Full Bridge MMC-HVDC
Authors: Yin Y J , Ning L H , Su Y , Zhao B Y , Xie C X , Zhang X L
Published: July 2019

Considering the FB-MMC, a generalized pre-charging strategy is proposed for the MMC-based systems. It contains two stages, no control charging and controllable charging. The circuit model of the converter is established in the no control charging stage, and the submodule capacitance can be charged to about 37% of rated voltage. During the controllable charging stage, we proposed grouping charging strategy, the blocked and bypassed strategy of each group sub-module is formulated. According to the circuit model, the capacitance voltage of each module can be charged to the rated value through this strategy. Finally, we set up a 9 level full bridge MMC-HVDC simulation system in PSCAD/EMTDC. The charging strategies are simulated, and the results show that the proposed control strategy is feasible.
A Comprehensive Evaluation for the Power Supply Reliability in Distribution Network based on Improved Entropy Method
Authors: Zhang Tao , Liu Hao , Zeng Qinghui , Li Guowei , Luo Rongbo , Li Hui , Wang Junbo
Published: July 2019

Considering power quality, a user-oriented and extended index system of power supply reliability has been built, and a comprehensive evaluation of power supply reliability based on improved entropy method in distribution network has been designed in this paper. Firstly, the paper has built an extended power supply reliability index system from 3 following aspects: the supply side, user side as well as the contrast, therefore, 7 new user-side indexes can reflect the real level of the power supply reliability by its continuity and availability, and 2 contrast indexes can reflect power supply reliability of the line among users in low and medium voltage; Secondly, considering its requirements and index characteristics, a comprehensive evaluation based on improved entropy method has been established. An initial index weights can be attained by this method, then, the weight matrix can be determined by a principle called ‘overflowing-value punishment’. What’s more the comprehensive values can also be attained after weighting and summation. Finally, its effectiveness can be verified by the result of case.
Reliability Evaluation Model of Power Grid Considering the Structural Reliability of Tower under Earthquake Conditions
Authors: Zhang Yagang , Kang Xiaoning , Zhang Xinyue , Guo Mingda , Xu Yini
Published: July 2019

The seismic disaster will cause serious damage to the power system. At present, the reliability evaluation of the power grid under earthquake conditions is mainly subjected to the approximate analysis of seismic performance, and the approximate analysis results can not meet the actual needs. In this paper, a reliability evaluation model of Power Grid considering the structural reliability of tower under earthquake conditions is proposed. The structural problems of tower and cable are analyzed directly by finite element simulation. The failure rate of transmission line is calculated by the structural reliability of tower and cable. After obtaining the reliability data of transmission line, the reliability of the power system under various seismic intensities is evaluated. Finally, the influence of the location of seismic source on the reliability of power system is analyzed. The results of the example analysis verify the accuracy and practicability of the proposed model and provide a reference for improving the seismic performance of the power system.
Comparative Core Loss Calculation Methods for Magnetic Materials under Harmonics Effect
Authors: Hein Htutzaw , Yue Shuaichao , Li Yongjian
Published: July 2019

The general data of industrial electromagnetics materials are given only for sinusoidal waveform, and mostly load is non-linear which may cause the harmonics effect. Steinmetz parameters, the well-known empirical equation, also differ under different frequencies and only for sinusoidal. Generalized Steinmetz equation and improved generalized Steinmetz equation are used to predicting the core loss under non-sinusoidal excitation. In this paper, a brief introduction of core loss calculation methods under non-sinusoidal excitations is discussed, and comparative analysis of under different harmonics orders and contents are presented. Ferrite N87 and Nano-crystalline 1K107 ring samples are magnetized as for experimental results. The experimental results show that the core loss depends not only frequency but also on the harmonics effect.
The Inspection of Power Quality Disturbances by Using Improved Extreme-value Lifting Morphological Wavelet Method
Authors: Zhang Huaying , Hu Ziheng , Li Yan , Ai Jingwen
Published: July 2019

For solving the difficulty of extracting the disturbing characteristics of the signals in power quality processing, and restraining the noise in the process of sampling, an improved extreme-value lifting morphological wavelet method is constructed. Firstly, morphological extreme-value operator is chosen to be the prediction operator and update operator, then the max-lifting and min-lifting morphological wavelets are constructed. Secondly, the improved extreme-value lifting morphological wavelet method is designed to further highlight local maxima and minima information of the disturbing signals based on the first step. Finally, the signals are dealt with this method, and the detail coefficients can be obtained, which have kept the disturbing characteristics of the signals. The result of simulation and analysis shows that this algorism owns the trait of simple, exactness, and de-noising.
Reactive Molecular Dynamics Simulation of Transformer Oil Pyrolysis Based on ReaxFF Reactive Force Field
Authors: Wang Xue-lei , Xu Wei , Zhu Wen-bing , Li Qing-min
Published: July 2019

Fast pyrolysis of transformer oil occurs at local high temperature caused by internal fault in power transformers and this may lead to transformer insulation deterioration. Because numerous subjects such as electrical, material and chemistry are involved and further research of microcosmic reaction mechanism is limited. In this paper ReaxFF reactive force field in which atom connectivity is presented by bond order is introduced to carry out reactive molecular dynamics simulation for transformer oil molecular models and their pyrolysis mechanism at high temperature are investigate. Alkanes C16H34, cycloalkanes C16H30 and aromatic hydrocarbons C16H18 with the same C atoms number 16 are taken as transformer oil examples and initiation pyrolysis mechanism, molecular interaction and products distribution during the whole process for different types of molecules at high temperature are simulated based on ReaxFF reactive force field reactive molecular dynamics. The results indicate that the pyrolysis of these three molecules is similar, the unimolecular dissociation is the main pathway at the early stage of pyrolysis while at the later period it is intermolecular radicals interaction dominated; the final products are mainly small hydrocarbons and radicals, such as C2H4, C3H6, CH4, H2, C2H6, C3H4, while most of the large hydrocarbons and radicals whose C atoms more than 6 mainly serve as intermediate products and decompose into small hydrocarbons and radicals with reactions going on. The difference is that the saturation of generated small molecule hydrocarbon increases for C16H34, C16H30 and C16H18.
The Research on the LCC Modelling and Economic Life Evaluation of Power Transformers
Authors: Li Na , Wang Xiaoliang , Zhu Zhenhua , Wang Yanan , Han Jianqiang , Xu Ran
Published: July 2019

In order to improve the economic life and reduced life cycle cost of the power transformers, the power transformer life cycle calculation model was built which considered key factors in all sections of the life cycle. Then the economic life evaluation method was researched to get the least total cost in the life cycle. At last, Practical example was calculated to obtain the life cycle cost and verified the accurateness of the method. The research result could provide theoretical support for equipment LCC management.
Study on Winding Looseness of Power Transformer Based on Vibration
Authors: Liu Hao , Zhang Zhendong , Zhang Jiangong , Huang Xiaolong , Wang Zelong , Zhao Lihua
Published: July 2019

The vibration of transformer is closely related to windings, so researching on vibration signal of power transformer has potential to realize online detection of winding looseness. In this paper, a series of tests have been made to obtain vibration signal by setting winding looseness on a 10/0.4kV three-phase transformer. A linear fitting equation has been obtained by fitting the amplitude of the 100Hz component of the vibration signal under different short-circuit currents. The results show that the slope of the fitting equation will increase when the winding becomes loose. The research results show the potential of this method in condition monitoring of power transformer.
The Power Transformer Operating Condition Evaluation Based on the Genetic Projection Pursuit Model
Authors: Hua Yue , Sun Yuanyuan , Li Na , Ma Shuo , Wang Erdong
Published: July 2019

Transformer is a key equipment in the power system, and it is very important to accurately evaluate its operating state. In this paper, a new method is proposed to evaluate the operating state of the power transformer based on the genetic projection pursuit model. The proposed method can provide a more objective evaluation result for the health condition of the transformers compared with the traditional methods. Firstly, a three-layer evaluation index system is established with the precautionary test, oil chromatographic analysis and insulating oil properties as the core content. And then, the grading standard of the lowest level index in the indicator system is established. Secondly, the genetic projection pursuit model is used in combination with the grading standard to obtain the intermediate layer evaluation results, which overcomes the disadvantages of the traditional transformer evaluation method which is greatly influenced by subjective factors. Finally, the eigenvalue weighting method is used to integrate the intermediate layer evaluation results to obtain the final result. Case study results show that the evaluation method of transformer operating state based on genetic projection pursuit model is reasonable and effective.
Application of Transformer Online Monitoring Data in State Evaluation
Authors: Bai Demeng , Qin Jiafeng , Wang Jian , Li Chengqi
Published: July 2019

The safety, stability and reliability of electrical equipment are directly related to the operation of the electrical system. Discovering various electrical equipment problems and effective treatment of the problem without delay will minimize the probability of electrical equipment failure. In electrical equipment monitoring and maintenance, Application of real-time monitoring is one of the most important elements. Real-time monitoring node can detect equipment failure promptly which will avoid the expansion of accident caused by the long test period or manual inspection. Working time of online monitoring nodes is limited by power consumption of node itself. Application of routing protocol can optimize energy consumption and extend working time of nodes.
Distributed Electric Vehicle Control Model Based on Blockchain
Authors: Guo Chuangxin , Huang Xiaobo , Zhu Chengzhi , Wang Xueping , Cao Xiu
Published: July 2019

With the global energy crisis and environmental problems in recent years, the calls for energy conservation and emission reduction is getting higher and higher, and while the research on smart grid in various countries is deepening, The development of electric vehicle-electric grid (Vehicle to Grid, V2G) has become the focus of all countries in the world. This paper first expounds the background and related concepts of V2G generation, and proposes the key point in V2G: V2G control model. The second section of the article introduces the work related to the traditional V2G model. In the third section of the article, the new technologies such as blockchain are introduced and combined with the traditional V2G control model, and finally proposes a new blockchain-based model of distributed electric vehicle control system.
Simulation and Optimal Design of Magnetic Coupler and its Shielding for EV Wireless Charger
Authors: Wang Songcen , Xu Chong , Niu Jintao , Wei Bin , Xu Jinxing , Cai Tao
Published: July 2019

This paper is focus on the coupler design of wireless power transfer (WPT) system for Electric Vehicle(EV). The author describes the coupler circuit model, design principles and steps, calibration methods and magnetic shielding methods for the coupler. Four shielding methods are simulated and compared in this paper. Through simulation, the author believes that aluminium plate shielding is the best for magnetic shielding, but it will cause more losses. Therefore, we need to do a more optimal design in the next study.
Research on Distributed Grid Connected Capacity Optimization Method for Power System Pre Dispatch
Authors: Xu Zhengqing , Yan Faqi , Liu Zhicheng , Xiao Yanwei , Sun Shu-qin , Yang Jing , Yan Wen-li
Published: July 2019

The particle swarm optimization algorithm with adaptive weight and Newton-Raphson method are studied to connect the distributed energy to the grid in this paper. We will discuss the research status of the current stage of the project. The basic principles and processes of particle swarm optimization algorithm and Newton-Raphson method are expounded, and their improvement and combination are made (as well as their improvement and combination ) so that they can optimize reactive power for networks with distributed energy better. Then the improved algorithm is applied to the IEEE-14 and IEEE-30 models and the reconstruction results are analyzed. The network loss and reactive power of the reconstruction network are declined, the voltage quality is improved. The SIMULARTOR software is used to establish and calculate the power flow of original model and reconstruction model of IEEE-14 and IEEE-30 respectively. The economic factors with grid supply point and connected capacity are analyzed to obtain the best ratio of power system at the same time. Compared with the above results, the results are basically consistent, and the accuracy and reliability of the algorithm are verified. Finally, considering the economic factors of the system, adjusting the connected capacity of the distributed energy-wind power and photovoltaic, and obtaining the best access ratio (proportion), the economical efficiency of the system is improved, and it has referential value.
A Multi-Weight Optimization Based Prediction Method for Distributed Generation
Authors: Zhang Yushu , Deng Hua , Qin Bing , Liu Jingyan , Zhang Pu , Huang Bi-bin
Published: July 2019

The development of distributed generation will be affected by the policy, and become more market-oriented. The impact factors of the future layout are various. In order to accurately predict the future layout of distributed generation and guide the planning, this paper presents a layout prediction method for distributed generation by multi-weight optimization. The method takes different impact factors into consideration and use the historical data to determine the weights of the factors with optimization method. The method can predict distributed generation layout in the target year accurately. The case of the distributed photovoltaic development in Shandong shows that the central region will become the main development region.
Research on Optimization Matching of Wind/Solar/Hydro/Storage Flexibility Resource System Considering Electric Vehicle Access
Authors: Qu Chunhui , Sun Wenwen , Tao Siyu , Xu Qingshan , Yang Bo
Published: July 2019

With the development of distributed generation technology and the requirement of power system flexibility, the research on multiple flexible resource optimization is carried out. Based on the traditional optimal configuration of wind-solar-hydro-storage system, this paper takes electric vehicle into consideration. Firstly, the model of each flexible resource is established. Then, a comprehensive evaluation index system is built. Taking the flexible resources in a city on the eastern coast of China as a case, multi-objective grey wolf optimization algorithm and entropy weight method are applied to do the optimization and evaluation. The simulation result shows that in the optimal configuration, not only the renewable resources can be effectively utilized, but also the requirement of load in different period can be meet. Moreover, the total investment can be greatly reduced. In addition, the participation of electric vehicles can not only improve the performance of the hybrid system, but also increase the income of EV holders.