bluuebunny/crossref_metadata_2025_split huggingface dataset:
Relative performance of white clover (
Authors: Jahufer M. Z. Z. , Ford J. L. , Cousins G. R. , Woodfield D. R. 
Published: November 2021

Assessment of the relative performance of white clover (Trifolium repens L.) cultivars, using multi-year and multi-location seasonal growth trials, is key to identification of material with specific and broad adaptation. This paper is based on a multi-year and multi-location study of 56 white clover entries comprising 14 commercial cultivars and 42 experimental synthetic lines evaluated for seasonal growth under rotational grazing across four locations in New Zealand over 4 years. The four locations (and animals grazing) were: Kerikeri (beef cattle), Aorangi (beef cattle), Ruakura (dairy cattle), Lincoln (sheep). Significant (P < 0.05) genotypic variation among the 56 entries, and genotype × year, genotype × location and genotype × season interactions, were estimated. We were able to identify cultivars and experimental synthetics with specific and broad adaptation to the three grazing management types. Cvv. AberDance, Apex, Demand, Prestige, Quartz and Riesling, with leaf size ranging from small to medium–large, showed highly above-average performance under sheep grazing. Synthetic lines 15 and 45 also had highly above-average performance under sheep grazing. Cvv. Legacy and Kopu II showed above-average performance under cattle and dairy grazing. Synthetics 15, 48, 49, 44, 22 and 18 and cv. Quartz had above-average performance under all three grazing managements. Synthetics 27, 33 and 38 had highly above-average performance across all three grazing managements and were superior to all 14 cultivars evaluated. Several of these superior synthetics are being tested across multiple grazing environments. Among the 14 cultivars evaluated, Legacy and Quartz showed superior seasonal growth performance across the three grazing managements. Quartz is being evaluated in several on-farm trials across temperate regions of the world.
Does the carbon skeleton of biochar contribute to soil phosphate sorption? A case study from paddy soils with woody biochar amendment
Authors: Qin Guobing , Yan Xiao , Wei Jinju , Wu Jianfu , Wei Zongqiang 
Published: November 2021

Context The phosphorus (P) sorption capacity of biochar and the effects of biochar amendment on soil P sorption and availability remain uncertain. Aims This study determined the specific contributions of the biochar inorganic component (mineral ash) and its carbon skeleton to the P sorption capacity of biochar. Methods A woody biochar and its acid-washed counterpart were added to two types of paddy soils with two P-retention capacities: high P sorption (HPS) and low P sorption (LPS). Key results Washing biochar with HCl solution drastically decreased the concentrations of calcium, magnesium, iron (Fe), and aluminium (Al) in the biochar. However, Fourier transform infrared and X-ray photoelectron spectroscopy spectra indicated that the washing procedure did not decrease the biochar organic carbon content and its surface functional groups. Acid-washed biochar showed nearly zero P sorption after 24 h of equilibration with P solution, and its incorporation had little effect on P sorption of the two paddy soils. Amendment with original alkaline woody biochar tended to increase P sorption capacity of LPS soils, but decreased that of HPS soils. The variations in Langmuir P sorption maxima, an indicator of soil P sorption capacity, among the soils and biochar treatments could be primarily explained by the amorphous Fe and Al concentrations, which indicates that the effect of biochar addition on soil P sorption was highly dependent on intrinsic soil P-retentive properties. Conclusion These results demonstrate that the biochar carbon skeleton had a very limited contribution to biochar P-retention capacity. Implications Our results suggest that the application of aged biochar with lower mineral contents to humid acidic highly weathered soils will have limited P retention capacity.
Generating a dynamical M2 brane from super-gravitons in a pp-wave background
Authors: Chen Yi-Fei , Lu J X , Zhang Nan 
Published: November 2021

Abstract
We present a detailed study of dynamically generating an M2 brane from super-gravitons (or D0 branes) in a pp-wave background possessing maximal spacetime SUSY. We have three kinds of dynamical solutions depending on the excess energy which appears as an order parameter signalling a critical phenomenon about the solutions. As the excess energy is below a critical value, we have two branches of the solution, one can have its size zero while the other cannot for each given excess energy. However there can be an instanton tunnelling between the two. Once the excess energy is above the critical value, we have a single solution whose dynamical behavior is basically independent of the background chosen and whose size can be zero at some instant. A by product of this study is that the size of particles or extended objects can grow once there is a non-zero excess energy even without the presence of a background flux, therefore lending support to the spacetime uncertainty principle.
MIX Reality Based Media Prototype For Learning Physics of Gravity And Kepler’s Law
Authors: Munawaroh L W , Serevina V , Iswanto B H 
Published: November 2021

Abstract
Gravity and Kepler’s Laws are materials that study natural phenomena, events or phenomena that reveal all the secrets of the universe. Based on the observations of several schools, there are difficulties for students understanding gravity and Kepler’s laws because they can not directly present 3D learning media in interactive classes. This study aims to develop a mixed reality-based media prototype for learning gravity physics and Kepler’s laws using special VR box glasses and markers to display 3D objects equipped with audio explanations, 3D animations, and evaluation questions. The research was conducted using the ADDIE development model (Analyze, design, develop, implement, and evaluate). To make it easier for students to use mix reality applications, the mix reality software design employs blender version 2.78, unity 5.1, Photoshop, the vuforia AR extension for unity, and the c # programming language. The trial of the feasibility of mix reality media was conducted by averaging the results of the validator’s assessment of each aspect of the assessment. Mixed reality media prototypes can help students understand gravity and Kepler’s laws.
PT

-symmetric classical mechanics
Authors: Bender Carl M , Hook Daniel W 
Published: November 2021

Abstract
This paper reports the results of an ongoing in-depth analysis of the classical trajectories of the class of non-Hermitian

PT

-symmetric Hamiltonians H = p2 + x2
(ix)
ε
(ε ⩾ 0). A variety of phenomena, heretofore overlooked, have been discovered such as the existence of infinitely many separatrix trajectories, sequences of critical initial values associated with limiting classical orbits, regions of broken

PT

-symmetric classical trajectories, and a remarkable topological transition at ε = 2. This investigation is a work in progress and it is not complete; many features of complex trajectories are still under study.
An introductory review on resource theories of generalized nonclassical light
Authors: Dey Sanjib 
Published: November 2021

Abstract
Quantum resource theory is perhaps the most revolutionary framework that quantum physics has ever experienced. It plays vigorous roles in unifying the quantification methods of a requisite quantum effect as wells as in identifying protocols that optimize its usefulness in a given application in areas ranging from quantum information to computation. Moreover, the resource theories have transmuted radical quantum phenomena like coherence, nonclassicality and entanglement from being just intriguing to being helpful in executing realistic thoughts. A general quantum resource theoretical framework relies on the method of categorization of all possible quantum states into two sets, namely, the free set and the resource set. Associated with the set of free states there is a number of free quantum operations emerging from the natural constraints attributed to the corresponding physical system. Then, the task of quantum resource theory is to discover possible aspects arising from the restricted set of operations as resources. Along with the rapid growth of various resource theories corresponding to standard harmonic oscillator quantum optical states, significant advancement has been expedited along the same direction for generalized quantum optical states. Generalized quantum optical framework strives to bring in several prosperous contemporary ideas including nonlinearity,

PT

-symmetric non-Hermitian theories, q-deformed bosonic systems, etc., to accomplish similar but elevated objectives of the standard quantum optics and information theories. In this article, we review the developments of nonclassical resource theories of different generalized quantum optical states and their usefulness in the context of quantum information theories.
Antilinear symmetry and the ghost problem in quantum field theory
Authors: Mannheim Philip D. 
Published: November 2021

Abstract
The recognition that the eigenvalues of a non-Hermitian Hamiltonian could all be real if the Hamiltonian had an antilinear symmetry such as PT stimulated new insight into the underlying structure of quantum mechanics. Specifically, it led to the realization that Hilbert space could be richer than the established Dirac approach of constructing inner products out of ket vectors and their Hermitian conjugate bra vectors. With antilinear symmetry one must instead build inner products out of ket vectors and their antilinear conjugates, and it is these inner products that would be time independent in the non-Hermitian but antilinearly symmetric case even as the standard Dirac inner products would not be. Moreover, and in a sense quite remarkably, antilinear symmetry could address not only the temporal behavior of the inner product but also the issue of its overall sign, with antilinear symmetry being capable of yielding a positive inner product in situations such as fourth-order derivative quantum field theories where the standard Dirac inner product is found to have ghostlike negative signature. Antilinear symmetry thus solves the ghost problem in such theories by showing that they are being formulated in the wrong Hilbert space, with antilinear symmetry providing a Hilbert space that is ghost free. Antilinear symmetry does not actually get rid of the ghost states. Rather, it shows that the reasoning that led one to think that ghosts were present in the first place is faulty. Implications of our results for constructing unitary quantum theories of gravity are presented.
Paths of unitary access to exceptional points
Authors: Znojil Miloslav 
Published: November 2021

Abstract
With an innovative idea of acceptability and usefulness of the non-Hermitian representations of Hamiltonians for the description of unitary quantum systems (dating back to the Dyson’s papers), the community of quantum physicists was offered a new and powerful tool for the building of models of quantum phase transitions. In this paper the mechanism of such transitions is discussed from the point of view of mathematics. The emergence of the direct access to the instant of transition (i.e., to the Kato’s exceptional point) is attributed to the underlying split of several roles played by the traditional single Hilbert space of states

ℒ

into a triplet (viz., in our notation, spaces

K

and

ℋ

besides the conventional

ℒ

). Although this explains the abrupt, quantum-catastrophic nature of the change of phase (i.e., the loss of observability) caused by an infinitesimal change of parameters, the explicit description of the unitarity-preserving corridors of access to the phenomenologically relevant exceptional points remained unclear. In the paper some of the recent results in this direction are summarized and critically reviewed.
Flow stress characterization of magnesium alloys at elevated temperatures: A review
Authors: Yoo J D , Kim M C , Kim E J , Razali M K , Joun M S 
Published: November 2021

Abstract
The flow behaviors of magnesium alloys are too complicated to be simply formulated in a mathematical form. Most researches have based metallurgically or phenomenologically on specific functions with many constants, which could be applied only to the limited magnesium alloys under specific conditions. In this study, a review on the studies of flow stress characterization of magnesium alloys is conducted and the possibility of using the traditional piecewise C-m model and its extension to characterize the magnesium alloys is emphasized. The formulations of major flow models are given with three typical applications to magnesium alloy AZ80 and its characteristics are demonstrated through comparison of the fitted flow behaviors with their associated experiments and various flow stress models including Arrehenius model, four Ludwik family models (Johnson Cook, Modified Johnson-Cook, Hensel-Spittel, Sutton-Luo), two Voce family models (Ebrahimi et al., Razali et al.) and C-m models.
Modelling and Numerical simulation of Nano-enhanced PV-PCM System for Heat Transfer Augmentation from the Panel
Authors: Charles Divyateja B , Unnikrishnan K S , Rohinikumar B 
Published: November 2021

Abstract
Phase change materials (PCMs) can effectively cool photovoltaic (PV) panels by the passive cooling technique, thereby enhancing its direct energy conversion efficiency. However, generally, PCMs have low thermal conductivity, and different methods can be employed to improve the heat transfer rate. Cooling techniques based on phase change materials (PCMs) enhanced by nano-sized solid particles are very promising. In this paper, a mathematical model is developed to simulate the performance analysis of PV attached with nano-enhanced PCM (NEPCM) integrated with fins and compare the same with that of pure PCM case. The system is oriented in a horizontal position and subjected to constant solar radiation flux of 1000 W/m
2. The PCM selected is RT25HC, and the nanoparticle used is CuO for the numerical study. The effects of volumetric concentrations (0%, 2%, and 4%) and fin number on the performance of the system are investigated numerically. Results show that adding nanoparticles is more effective in no fin case compared to finned cases. The maximum reduction in average PV temperature of 2.02 °C is obtained for no fin case with the nanoparticles’ volumetric concentration of 4%. Further enhancement in liquid fraction and energy storage in NEPCM is also achieved compared to the pure PCM system.
Research on Governor Parameter Optimization to Suppress Ultra-Low Frequency Oscillation of Power System Caused by Hydropower Unit
Authors: Yan Wei , Sun Yunbang 
Published: November 2021

Abstract
In the actual power system with hydropower, long-time and ultra-low frequency oscillation events occur many times. It is found that the unreasonable setting of governor parameters is an important reason for the oscillation. Firstly, the single machine on load system model is used to analyse the relationship between the PID parameters of the governor and the system stability, then the relationship between oscillation mode and PID parameters of governor is analyzed by eigenvalue analysis method, and the negative damping provided by speed regulation system is analyzed by damping torque method, and then the particle swarm optimization algorithm is used to optimize the PID parameters. Through the analysis of the step response of the single machine system before and after the optimization and the damping torque coefficient provided by the speed regulation system, it shows the effectiveness of the optimization algorithm. Finally, in the simulation platform MATLAB/SIMULINK, a single machine load system model which is closer to the actual power grid is built. The governor parameters of the generator are simulated and verified, and the PID parameters are adjusted by using the parameters obtained by the optimization algorithm. The results show that the optimized parameters have a good suppression for the ultra-low frequency oscillation.
Modelling and simulation of house load operation of HPR1000 NPP
Authors: Chen Xiaowei , Sun Hui , Zhai Changchun , Zhang Qingliang 
Published: November 2021

Abstract
In this paper, the house load operation of the unit is evaluated, taking the third-generation Nuclear Power Plant (NPP) HPR1000 as an example, considering the primary loop, the secondary loop and the entire on-site electrical power systems. The main work of this study is as following: Firstly, acceptance criteria and specific numerical requirements are set out; the simulation result should meet the relevant criteria. Secondly, the Simulink simulation model of the entire system is built in detail, which can be divided into primary loop, secondary loop and on-site electrical power system parts, with emphasis on the simulation modelling of the turbine generator unit. The component models of each part and their corresponding connection relationships of each part are shown and given. Finally, a house load operation simulation is performed, and the result is compared with the acceptance criteria to verify that whether the generator has the ability to transfer to house load operation as designed.
Application of extraction steam graded heat storage in peak shaving of condensing units
Authors: Zou Siyu , Zheng Puyan , Zhu Qunzhi , Bai Tianyu , Wei Qingyuan , Wei Guoqing 
Published: November 2021

Abstract
In order to alleviate the peak shaving pressure of power grid and further improve the deep peak shaving capacity of coal-fired units, this paper applies staged heat storage to condensing units. Under the condition of constant boiler load, the heat of regenerative steam extraction is stored to reduce the electrical load output of the unit. Taking a 660MW ultra-supercritical unit as an example,30%THA,40%THA and 50%THA were taken as the initial conditions of heat storage respectively to discuss the peak shaving range and power regeneration efficiency of different extraction steam positions for heat storage. The results show that the “storage 1# HP heater extraction steam” scheme with “two-stage three tank” heat storage and release structure has the largest peak shaving range of 37.3%~56.9% under 50% initial conditions. When the “two-stage three tank” heat storage and release structure selects the “storage 1# HP heater extraction steam ”scheme under 40% initial working condition, the “power regeneration efficiency” reaches the highest——78.3%. And the “power regeneration efficiency” of “two stage three tank” storage structure are always higher than the “single-stage” storage structure.
Research on typical application in distribution station area
Authors: Lu Dan , Liu Yang , Li Jungang , Zhang Linjuan , Xu Changqing , Wang Lili , Guo Jianyu 
Published: November 2021

Abstract
The traditional power distribution station area lacks advanced functions for power distribution, and it is not conducive to operation and maintenance management. In order to improve the intelligent level of the distribution station area, it is constructed around with the intelligent distribution transformer terminal. Take intelligent distribution transformer terminal as the centre, the schemes of some typical applications, such as topology identification, line impedance analysis and three-phase unbalanced governance, are researched and designed to support the construction of distribution station area.
Oscillation analysis of doubly-fed unit considering wind speed variation
Authors: Wan Ke 
Published: November 2021

Abstract
Tower shadow effect and wind shear may cause power oscillation of the unit. In order to study the influence of tower shadow effect and wind shear on the output power of wind turbine, a doubly-fed turbine was taken as an example. Firstly, the influence of tower shadow effect and wind shear was considered to study the periodic power fluctuation characteristics of wind turbines. Then, according to the dynamic model of mechanical transmission mechanism, the influences of the inertia constants of generator, fan and the stiffness coefficient of the shaft system on the transient performance of the wind power generation system were considered respectively. Finally, a single machine infinite bus system model including wind speed model is built on PSCAD/EMTDC platform for simulation. The results show that the tower shadow effect and wind shear component can cause the power fluctuation of the turbine. When the power fluctuation frequency of the turbine is equal to the natural oscillation frequency of the wind turbine shafting, the resonance of the turbine occurs, and the amplitude of oscillation is the largest. Changing the transmission parameters will affect the power fluctuation amplitude and speed response speed of the unit.
Application of anti integral saturation cascade PID control algorithm in superheated steam temperature control
Authors: Sun Zhe , Liu Chunhui , Li Ming , Zhao Junda , Xu Yao 
Published: November 2021

Abstract
At present, most units adopt the superheated steam temperature control system with cascade PID control structure. However, because most cascade PID control algorithms have no anti-integral saturation function, the automatic control of boiler superheated steam temperature cannot be put into operation normally. On the existing cascade PID superheated steam temperature regulation system, we judge the deviation value of the main regulator and the output value of the auxiliary regulator, and cancel the integration function at an appropriate time. When the input deviation signal turns over, the regulating system can immediately enter the normal regulating state, so that the cascade PID superheated steam temperature regulating system can timely and accurately regulate the superheated steam temperature. The fuel cost is saved by about 155,600 yuan per year.
Research on Real-time Monitoring of Launch Vehicle Deformation Using Fiber Bragg Grating Sensor
Authors: Liang Zhuang , Zhang Yulin 
Published: November 2021

Abstract
To solve the problem that the curvature information of the large flexible rocket body affects the attitude control of the rocket body, a shape reconstruction method based on optical fiber strain sensing is proposed in this paper, which can measure the bow deformation and vibration state of the rocket in real time as the input data for adjusting the attitude control of the rocket. In this scheme, the dynamics of flexible rocket can be solved stably and quickly. In order to verify the reconstruction method, the beam model was used as the experimental analysis object, and the vibration information such as deformation of the beam model was identified through the strain value measured by fiber Bragg grating (FBG) sensors. The results show that the deformation reconstruction method can well restore the deformation and rotation angle of the beam system and has good stability and real-time performance. This method can provide a theoretical basis for the real-time deformation calculation and high-precision attitude control of future flexible launch vehicle.
A predictive control method for reducing power backflow in DC/AC matrix converter
Authors: Xia Zhipeng , Jin Ping , Chang Ling 
Published: November 2021

Abstract
In recent years, DC/AC matrix converter with higher power density have become an attractive alternative to traditional voltage source converters. The traditional PI control has been employed to achieve accurate control, but its dynamic response and stability need to be improved. In this paper, a model predictive control (MPC) with reducing power backflow is introduced in an isolated DC/AC matrix converter with a loosely coupled high-frequency transformer (LCHFT). Prediction model and optimal function model are established to improve the dynamic response of the system and reduce the power backflow.