bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal-responsive genetic and epigenetic regulation of DAM cluster controlling dormancy and chilling requirement in peach floral buds
Authors: Zhu Hong , Chen Pao-Yang , Zhong Silin , Dardick Chris , Callahan Ann , An Yong-Qiang , van Knocker Steve , Yang Yingzhen , Zhong Gan-Yuan , Abbott Albert , Liu Zongrang
Published: August 2020

TheDormancy-associated MADS-box(DAM) gene cluster in peach serves as a key regulatory hub on which the seasonal temperatures act and orchestrate dormancy onset and exit, chilling response and floral bud developmental pace. Yet, how different temperature regimes interact with and regulate the six linkedDAMgenes remains unclear. Here, we demonstrate that chilling downregulatesDAM1 and DAM3–6in dormant floral buds with distinct patterns and identifyDAM4as the most abundantly expressed one. We reveal multiple epigenetic events, with tri-methyl histone H3 lysine 27 (H3K27me3) induced by chilling specifically inDAM1andDAM5, a 21-nt sRNA inDAM3and a ncRNA induced inDAM4. Such induction is inversely correlated with downregulation of their cognateDAMs. We also show that the sixDAMs were hypermethylated, associating with the production of 24-nt sRNAs. Hence, the chilling-responsive dynamic of the different epigenetic elements and their interactions likely define distinct expression abundance and downregulation pattern of eachDAM. We further show that the expression of the fiveDAMs remains steadily unchanged or continuously downregulated at the ensuing warm temperature after chilling, and this state of regulation correlates with robust increase of sRNA expression, H3K27me3 and CHH methylation, which is particularly pronounced inDAM4. Such robust increase of repressive epigenetic marks may irreversibly reinforce the chilling-imposed repression ofDAMs to ensure flower-developmental programming free from any residualDAMinhibition. Taken together, we reveal novel information about genetic and epigenetic regulation of theDAMcluster in peach, which will be of fundamental significance in understanding of the regulatory mechanisms underlying chilling requirement and dormancy release, and of practical application for improvement of plasticity of flower time and bud break in fruit trees to adapt changing climates.
Defining strawberry shape uniformity using 3D imaging and genetic mapping
Authors: Li Bo , Cockerton Helen M. , Johnson Abigail W. , Karlström Amanda , Stavridou Eleftheria , Deakin Greg , Harrison Richard J.
Published: August 2020

Strawberry shape uniformity is a complex trait, influenced by multiple genetic and environmental components. To complicate matters further, the phenotypic assessment of strawberry uniformity is confounded by the difficulty of quantifying geometric parameters ‘by eye’ and variation between assessors. An in-depth genetic analysis of strawberry uniformity has not been undertaken to date, due to the lack of accurate and objective data. Nonetheless, uniformity remains one of the most important fruit quality selection criteria for the development of a new variety. In this study, a 3D-imaging approach was developed to characterise berry shape uniformity. We show that circularity of the maximum circumference had the closest predictive relationship with the manual uniformity score. Combining five or six automated metrics provided the best predictive model, indicating that human assessment of uniformity is highly complex. Furthermore, visual assessment of strawberry fruit quality in a multi-parental QTL mapping population has allowed the identification of genetic components controlling uniformity. A “regular shape” QTL was identified and found to be associated with three uniformity metrics. The QTL was present across a wide array of germplasm, indicating a potential candidate for marker-assisted breeding, while the potential to implement genomic selection is explored. A greater understanding of berry uniformity has been achieved through the study of the relative impact of automated metrics on human perceived uniformity. Furthermore, the comprehensive definition of strawberry shape uniformity using 3D imaging tools has allowed precision phenotyping, which has improved the accuracy of trait quantification and unlocked the ability to accurately select for uniform berries.
A modular programmed biphasic dual-delivery system on 3D ceramic scaffolds for osteogenesisin vitroandin vivo
Authors: Chen Guanghua , Kong Pengyu , Jiang Anlong , Wang Xiaoyan , Sun Yi , Yu Tailong , Chi Hui , Song Chengchao , Zhang Hailong , Subedi Dipendra , Ravi Kumar Prajapati , Bai Kaisong , Liu Kunyu , Ji Ye , Yan Jinglong
Published: August 2020

Single-factor delivery is the most common characteristic of bone tissue engineering techniques.
In vivo pharmacodynamic evaluation of antidepressants based on flux mitochondrial Cys in living mice via near infrared fluorescence imaging
Authors: Wang Xin , Zha Jiali , Zhang Wei , Zhang Wen , Tang Bo
Published: August 2020

We proposed a new strategy for in vivo evaluation of antidepressants through NIRF imaging for mitochondrial Cys in the mouse brain.
Responsive polymeric Janus cage
Authors: Zhang Linlin , Shi Siyu , Zhang Guolin , Song Ximing , Sun Dayin , Liang Fuxin , Yang Zhenzhong
Published: August 2020

A thermo-responsive polymeric Janus cage has demonstrated highly efficient separation of oil/water emulsions independent of the type of emulsion and surfactant.
Direct plasma phosphorization of Cu foam for Li ion batteries
Authors: Li Guoling , Wang Yuetao , Guo Heng , Liu Zhiliang , Chen Pohua , Zheng Xinyao , Sun Junliang , Chen Hui , Zheng Jie , Li Xingguo
Published: August 2020

P is a promising anode material for Li ion batteries, herein, we use plasma activated phosphorous vapor to deposite P on the Cu current collector, which in situ converts the surface of Cu into Cu3P, leading to a monolithic electrode.
Carbon cloth as an advanced electrode material for supercapacitors: progress and challenges
Authors: Liu Xiaoqing , Xu Wei , Zheng Dezhou , Li Zhifeng , Zeng Yinxiang , Lu Xihong
Published: August 2020

This paper provides a comprehensive overview on the design and modification of carbon cloth as advanced electrodes for high-performance supercapacitor assembly.
Micro/nanostructured TiNb2O7-related electrode materials for high-performance electrochemical energy storage: recent advances and future prospects
Authors: Wang Hongkang , Qian Ruifeng , Cheng Yonghong , Wu Hong-Hui , Wu Xianwen , Pan Kunming , Zhang Qiaobao
Published: August 2020

This Review summarized the latest progress in structural engineering, material fabrication and enhancement of the electrochemical performances of micro/nanostructured TiNb2O7 and its analogues for high-performance energy storage systems.
Megamerger of MOFs and g-C3N4 for energy and environment applications: upgrading the framework stability and performance
Authors: Zhang Gaoxia , Huang Danlian , Cheng Min , Lei Lei , Chen Sha , Wang Rongzhong , Xue Wenjing , Liu Yang , Chen Yashi , Li Zhihao
Published: August 2020

Metal–organic frameworks (MOFs) possess large surface area, adjustable pore size and synthetic adaptability which make them promising candidates for diverse applications.
Defect-engineered transition metal hydroxide nanosheets realizing tumor-microenvironment-responsive multimodal-imaging-guided NIR-II photothermal therapy
Authors: Yang Li , Zhu Xiaojiao , Xu Tianren , Han Fusen , Liu Gang , Bu Yingcui , Zhang Jie , Zhang Feng , Zhou Hongping , Xie Yi
Published: August 2020

Defect engineering strategy was utilized to regulate the photophysical property of 2D transitional metal-based nanomaterials, the S-Ni(OH)2 nanosheets exhibited response to the tumor microenvironment and as 2D photothermal transduction agents in NIR-II bio-window.
Novel Aurivillius Bi4Ti3−2xNbxFexO12 phases with increasing magnetic-cation fraction until percolation: a novel approach for room temperature multiferroism
Authors: Algueró Miguel , Pérez-Cerdán Miguel , del Real Rafael P. , Ricote Jesús , Castro Alicia
Published: August 2020

Aurivillius oxides with general formula (Bi2O2)(Am−1BmO3m+1) are being extensively investigated for room-temperature multiferroism and magnetoelectric coupling.
Road traffic network state prediction based on a generative adversarial network
Authors: Xu Dongwei , Peng Peng , Wei Chenchen , He Defeng , Xuan Qi
Published: August 2020

Traffic state prediction plays an important role in intelligent transportation systems, but the complex spatial influence of traffic networks and the non‐stationary temporal nature of traffic states make it a challenging task. In this study, a new traffic network state prediction model for freeways based on a generative adversarial framework is proposed. The generator based on the long short‐term memory networks is adopted to generate future traffic states, and a discriminator with multiple fully connected layers is applied to simultaneously ensure the prediction accuracy. The results of experiments show that the proposed framework can effectively predict future traffic network states and is superior to the baselines.
Semi‐supervised double duelling broad reinforcement learning in support of traffic service in smart cities
Authors: Tang Jing , Wei Xin , Zhao Jialin , Gao Yun
Published: August 2020

Traffic service is an important building block of smart cities, affecting citizens’ travel quality. Due to the characteristics of complicated and volatile traffic scenarios, fast and accurate modelling and processing requirements are vital for traffic service, such as traffic congestion solutions. Traditional deep reinforcement learning (DRL) approach can make decisions autonomously, but its complex network structure leads to time‐consuming training and updating processes. In addition, it is not always feasible to provide a large amount of tagged data in real life. To solve these problems, this study proposes a semi‐supervised double duelling broad reinforcement learning (semi‐DDBRL) approach based on the broad reinforcement learning (BRL). It incorporates some algorithmic improvements into the BRL, such as duelling network and double Q ‐learning network, and adds semi‐supervised learning to improve the accuracy of modelling and decision making. As a case study of smart city applications, the authors apply the proposed semi‐DDBRL approach to the problem of traffic congestion. Based on the experiments, their approach can have a faster execution time than the DRL approach. Moreover, compared with the BRL approach, their approach can improve the performance by 11.7%.
Predictive model for battery life in IoT networks
Authors: Reddy Maddikunta Praveen Kumar , Srivastava Gautam , Reddy Gadekallu Thippa , Deepa Natarajan , Boopathy Prabadevi
Published: August 2020

The internet of things (IoT) is prominently used in the present world. Although it has vast potential in several applications, it has several challenges in the real‐world. One of the most important challenges is conservation of battery life in devices used throughout IoT networks. Since many IoT devices are not rechargeable, several steps to conserve the battery life of an IoT network can be taken using the early prediction of battery life. In this study, a machine learning based model implementing a random forest regression algorithm is used to predict the battery life of IoT devices. The proposed model is experimented on ‘Beach Water Quality – Automated Sensors’ data set generated from sensors in an IoT network from the city of Chicago, USA. Several pre‐processing techniques like normalisation, transformation and dimensionality reduction are used in this model. The proposed model achieved a 97% predictive accuracy. The results obtained proved that the proposed model performs better than other state‐of‐art regression algorithms in preserving the battery life of IoT devices.
Design and optimisation of multimodal traffic strategy for low‐mobility individuals
Authors: Zhang Tao , Yang Yang , Cheng Gang , Jin Minjie , Ren Gang
Published: August 2020

Recently, low‐mobility individuals have drawn growing attention in the traffic organisation field. Therefore, following the previous research efforts, this study tries to design and optimise a multimodal traffic strategy for low‐mobility individuals. First, the preliminary application conditions and implementation effects of different traffic strategies are analysed to determine feasible multimodal traffic strategies for low‐mobility individuals based on the optimisation goal and strategic orientation. Then, an optimisation model is proposed to select the optimal strategies from feasible strategies for different travel modes, aiming to minimise the weighted sum of public transport, walking, non‐vehicle‐based transportation, travelling by private car and strategy implementation costs. An appropriate heuristic algorithm is developed to solve the optimisation model. Finally, the case study of Wenling is presented to verify the feasibility and practicality of the proposed multimodal traffic strategy design and optimisation for low‐mobility individuals. The results show that the proposed multimodal traffic strategy has stronger positive than negative effects from the travel cost aspect. The findings presented in this work can provide a reference for other, more in‐depth, studies on the multimodal traffic travel of low‐mobility individuals in the future.
Rider model identification: neural networks and quasi‐LPV models
Authors: Loiseau Paul , Boultifat Chaouki Nacer Eddine , Chevrel Philippe , Claveau Fabien , Espié Stéphane , Mars Franck
Published: August 2020

The current development of Advanced Rider Assistance Systems (ARAS) would interestingly benefit from precise human rider modelling. Unfortunately, important questions related to motorbike rider modelling remain unanswered. The goal of this study is to propose an original cybernetic rider model suitable for ARAS oriented applications. The identification process is based on experimental data recorded in real driving conditions with an instrumented motorbike. Starting with a dynamic neural network, the proposed methodology firstly presents a non‐linear rider model. The analysis of this model and some analogies with car driver modelling allow to deduce a quasi‐linear parameter varying (quasi‐LPV) rider model with explicit speed dependence and a clear distinction between linear and non‐linear dynamics. This quasi‐LPV model is further analysed and simplified and finally leads to a rider model with a reduced number of parameters and nice prediction capabilities. Such a model opens up interesting perspectives for the improvement of rider assistances.
ZigBee wireless smart plug network with RSSI multi‐lateration‐based proximity estimation and parallelised machine learning capabilities for demand response
Authors: Deese Anthony S. , Daum Julian
Published: August 2020

This study explores how wireless ZigBee technology may be applied to automation of electric loads in residential and commercial spaces, allowing to participate in demand response initiatives. The authors discuss development of a custom smart plug with sensing, wireless communication, and electric load actuation capabilities along with several innovative upgrades. There are many commercially available smart plugs that contain multiple sensors and relays. However, very few provide the ability to effectively estimate the proximity between modules or the ability to perform robust system‐wide optimisation. The authors propose two innovative smart plug eco‐system improvements. One is the use of a received signal strength indicator (RSSI) multi‐lateration‐based method to estimate the relative proximities of modules. The RSSI values for almost all transmission paths within the ZigBee network are acquired via the authors' forced network reconfiguration algorithm, addressing the limitations of RSSI observation within a star structure. A second innovation is the development of a parallelised neural network training method for application to load automation. The authors use a k‐means clustering algorithm to divide training data into subsets such that training may be parallelised.
Obstacle‐resistant hybrid localisation algorithm
Authors: Kargar‐Barzi Amin , Mahani Ali
Published: August 2020

A wide range of wireless sensor applications need to know the position of the nodes in a network area. So, finding the location of nodes, which is known as the localisation, has become a challenge in wireless sensor networks. This study proposed Diagonal‐Centroid and Diagonal‐Particle Swarm Optimisation (PSO) methods, which are regarded as two novel anchor‐based localisation techniques. In these methods, the anchor node diagonally traversed the network area and transmit broadcast packets of its position. In Diagonal‐Centroid method, nodes estimated their location by the average of the received position while, in the second method, the best tree positions were selected by a heuristic algorithm to estimate the position of the nodes. In this study, the authors extend their analysis to three different scenarios including the networks with and without obstacles to investigate the effect of the obstacles in network localisation, as well as the network with different node deployments to check out the localisation coverage area and network performance. All scenarios were implemented in OMNeT++ simulator, and based on the results, the Diagonal‐Centroid technique had the best accuracy, whereas Diagonal‐PSO had better performance regarding the accuracy and energy consumption compared to those reported in the other related studies.
Distributed multi‐agent deep reinforcement learning for cooperative multi‐robot pursuit
Authors: Yu Chao , Dong Yinzhao , Li Yangning , Chen Yatong
Published: August 2020

As a popular research topic in the area of distributed artificial intelligence, the multi‐robot pursuit problem is widely used as a testbed for evaluating coordinated and cooperative strategies in multi‐robot systems. This study the problem of multi‐robot pursuit game using reinforcement learning (RL) techniques is studied. Unlike most existing studies that apply fully centralised deep RL methods based on the centralised‐learning and decentralised‐execution scheme, the authors propose a fully decentralised multi‐agent deep RL approach by modelling each agent as an individual deep RL agent that has its own individual learning system (i.e. individual action‐value function, individual leaning update process, and individual action output). To realise coordination among agents, the limited information of other environmental agents is used as input of the learning process. Experimental results show that both distributed and centralised approaches can ultimately solve the pursuit‐evasion problem in different dimensions, but the learning efficiency and coordination performance of the proposed distributed approach are much better than the traditional centralised approach.
Uncovering interest group participation in Germany: web collection of written statements in ministries and the parliament
Authors: Rasch Daniel , Spohr Florian , Eising Rainer , Ress Simon
Published: August 2020

This article discusses web collection of interest group statements on bills as a data source. Written statements allow the identification of actors active in policy-making as well as those actors’ positions, lobbying coalitions and issue saliency. These data also can contribute to the measurement of interest groups’ influence on legislation. Taking web collection from the German parliament’s and ministries’ web pages as an example, we demonstrate the collection process and the merits and limitations of employing written statements as identificatory data. Our analysis of statements submitted by interest groups, private firms and policy experts to four federal ministries and the respective parliamentary committees in the years 2015 and 2016 reveals differences between parliamentary and ministerial consultations. Although ministries have invited written statements for fewer draft laws than parliamentary committees, they received far more statements from interest groups. The reason is that German ministries often issue open calls, in which all actors are given the opportunity to comment on legislation, whereas the German parliament invites selected interest group representatives and other experts. As a further result, ministries are mostly contacted by business groups, whereas parliamentary committees use their gatekeeper function to balance interests.
Photoelectron spectra explain how ammonia solutions become metallic
Authors: Middleton Christine
Published: August 2020

The gradual emergence of delocalized electron states in lithium–ammonia solutions underlies their transition.
Could hydrogen bail out nuclear power?
Authors: Kramer David
Published: August 2020

As nuclear-powered water electrolysis becomes cheaper, it could compete with the current, carbon-intensive hydrogen production process.
Sarah Frances Whiting and the “photography of the invisible”
Authors: Cameron John S. , Musacchio Jacqueline Marie
Published: August 2020

A team of women working in the physics laboratory at Wellesley College carried out some of the first successful x-ray experiments in the US.
Does new physics lurk inside living matter?
Authors: Davies Paul
Published: August 2020

The link between information and physics has been implicit since James Clerk Maxwell introduced his famous demon. Information is now emerging as a key concept to bridge physics and biology.
Eco-evolutionary control of pathogens
Authors: Lässig Michael , Mustonen Ville
Published: August 2020

Significance

Vaccinations and therapies targeting evolving pathogens aim to curb the pathogen and to steer it toward a controlled evolutionary state. Control is leveraged against the pathogen’s intrinsic evolutionary forces, which in turn, can drive an escape from control. Here, we analyze a simple model of control, in which a host produces antibodies that bind the pathogen. We show that the leverages of host (or external intervention) and pathogen are often highly imbalanced: an error threshold separates parameter regions of efficient control from regions of compromised control, where the pathogen retains the upper hand. Because control efficiency can be predicted from few measurable fitness parameters, our results establish a proof of principle how control theory can guide interventions against evolving pathogens.
Parkinson’s disease-related phosphorylation at Tyr39 rearranges α-synuclein amyloid fibril structure revealed by cryo-EM
Authors: Zhao Kun , Lim Yeh-Jun , Liu Zhenying , Long Houfang , Sun Yunpeng , Hu Jin-Jian , Zhao Chunyu , Tao Youqi , Zhang Xing , Li Dan , Li Yan-Mei , Liu Cong
Published: August 2020

Significance

Posttranslational modifications (PTMs) play an important role in modulating α-syn structure, function, and pathology. Phosphorylation commonly applies to pathological α-syn aggregation in Lewy bodies and is a pathological hallmark of Parkinson’s disease (PD). Here, we obtain homogeneous α-syn fibrils formed by semisynthesized α-syn with site-specific phosphorylation at Y39. The synthetic fibril recapitulates the neuropathology and degradation resistance of endogenous pY39 α-syn aggregation in PD. Cryo-EM structure determination of the pY39 α-syn fibril reveals a fold of α-syn with the entire N terminus involved in the fibril core attracted by pY39. This structure illuminates the mechanism of pY39 pathology and highlights the importance of PTMs in defining the structure and pathology of amyloid aggregation in neurodegenerative diseases.
The synthesis of xyloglucan, an abundant plant cell wall polysaccharide, requires CSLC function
Authors: Kim Sang-Jin , Chandrasekar Balakumaran , Rea Anne C. , Danhof Linda , Zemelis-Durfee Starla , Thrower Nicholas , Shepard Zachary S. , Pauly Markus , Brandizzi Federica , Keegstra Kenneth
Published: August 2020

Significance

Plant cells have a polysaccharide-based wall that maintains their structural and functional integrity and determines their shape. Reorganization of wall components is required to allow growth and differentiation. One matrix polysaccharide that is postulated to play an important role in this reorganization is xyloglucan (XyG). While the structure of XyG is well understood, its biosynthesis is not. Through genetic studies with
Arabidopsis CSLC
genes, we demonstrate that they are responsible for the synthesis of the XyG glucan backbone. A quintuple
cslc
mutant is able to grow and develop normally but lacks detectable XyG. These results raise important questions regarding cell wall structure and its reorganization during growth. The series of
cslc
mutants will be valuable tools for investigating these questions.
Propagation of shaped beam through uniaxially anisotropic chiral slab*
Authors: Wang Ming-Jun , Zhang Jia-Lin , Zhang Hua-Yong , Wang Zi-Han
Published: August 2020

A general solution is obtained to a canonical problem of the reflection and refraction of an arbitrary shaped beam by using a uniaxially anisotropic chiral slab. The reflected, internal as well as refracted shaped beams are expanded in terms of cylindrical vector wave functions, and the expansion coefficients are determined by using the boundary conditions and method of moments procedure. As two typical examples, the normalized field intensity distributions are evaluated for a fundamental Gaussian beam and Hermite–Gaussian beam, and some propagation properties, especially the negative refraction phenomenon, are discussed briefly.
Zero-point fluctuation of hydrogen bond in water dimer from ab initio molecular dynamics*
Authors: Jiang Wan-Run , Wang Rui , Ren Xue-Guang , Zhang Zhi-Yuan , Li Dan-Hui , Wang Zhi-Gang
Published: August 2020

Dynamic nature of hydrogen bond (H-bond) is central in molecular science of substance transportation, energy transfer, and phase transition in H-bonding networks diversely expressed as solution, crystal, and interfacial systems, thus attracting the state-of-the-art revealing of its phenomenological edges and sophisticated causes. However, the current understanding of the ground-state fluctuation from zero-point vibration (ZPV) lacks a firm quasi-classical base, concerning three basic dimensions as geometry, electronic structure, and interaction energy. Here, based on the ab initio molecular dynamics simulation of a ground-state water dimer, temporally separated fluctuation features in the elementary H-bond as the long-time weakening and the minor short-time strengthening are respectively assigned to two low-frequency intermolecular ZPV modes and two O–H stretching ones. Geometrically, the former modes instantaneously lengthen H-bond up to 0.2 Å whose time-averaged effect coverages to about 0.03 Å over 1-picosecond. Electronic-structure fluctuation crosses criteria’ borders, dividing into partially covalent and noncovalent H-bonding established for equilibrium models, with a 370% amplitude and the district trend in interaction energy fluctuation compared with conventional dragging models using frozen monomers. Extended physical picture within the normal-mode disclosure further approaches to the dynamic nature of H-bond and better supports the upper-building explorations towards ultrafast and mode-specific manipulation.
Multi-scale elastoplastic mechanical model and microstructure damage analysis of solid expandable tubular*
Authors: Guo Hui-Juan , Liu Ying-Hua , Su Yi-Nao , Zhang Quan-Li , Zhan Guo-Dong
Published: August 2020

We present an in-depth study of the failure phenomenon of solid expandable tubular (SET) due to large expansion ratio in open holes of deep and ultra-deep wells. By examining the post-expansion SET, lots of microcracks are found on the inner surface of SET. Their morphology and parameters such as length and depth are investigated by use of metallographic microscope and scanning electron microscope (SEM). In addition, the Voronoi cell technique is adopted to characterize the multi-phase material microstructure of the SET. By using the anisotropic elastoplastic material constitutive model and macro/microscopic multi-dimensional cross-scale coupled boundary conditions, a sophisticated and multi-scale finite element model (FEM) of the SET is built successfully to simulate the material microstructure damage for different expansion ratios. The microcrack initiation and growth is simulated, and the structural integrity of the SET is discussed. It is concluded that this multi-scale finite element modeling method could effectively predict the elastoplastic deformation and the microscopic damage initiation and evolution of the SET. It is of great significance as a theoretical analysis tool to optimize the selection of appropriate tubular materials and it could be also used to substantially reduce costly failures of expandable tubulars in the field. This numerical analysis is not only beneficial for understanding the damage process of tubular materials but also effectively guides the engineering application of the SET technology.
High efficient Al: ZnO based bifocus metalens in visible spectrum*
Authors: Wang Pengdi , Zeng Xianghua
Published: August 2020

The optical components of the visible light band are widely used in daily life and industrial development. However due to the serious loss of light and the high cost, the application is limited. The broadband gap metasurface will change this situation due to its low absorption and high efficiency. Herein, we simulate a size-adjustable metasurface of the Al doped ZnO (AZO) nanorod arrays based on finite difference time domain method (FDTD) which can realize the conversion of amplitude polarization and phase in the full visible band. The corresponding theoretical polarization conversion efficiency can reach as high as 91.48% (450 nm), 95.27% (530 nm), and 91.01% (65 nm). The modulation of focusing wavelength can be realized by directly adjusting the height of the AZO nanorod. The designed half-wave plate and metalens can be applied in the imaging power modulation halfwave conversion and enriching the spectroscopy.
Effect of patterned hydrodynamic slip on electromagnetohydrodynamic flow in parallel plate microchannel*
Authors: Yang Chun-Hong , Jian Yong-Jun
Published: August 2020

A fully developed electromagnetohydrodynamic (EMHD) flow through a microchannel with patterned hydrodynamic slippage on the channel wall is studied. The flow is driven by the Lorentz force which originates from the interaction between an externally imposed lateral electric field and a perpendicular magnetic field. The governing equations for the velocity with patterned slip boundary conditions are solved analytically by perturbation techniques under the assumption of small Reynolds number Re. In addition, the numerical solutions for the velocity are obtained by using the finite-difference method, and they are found to be in good agreement with the analytical solutions within admissible parameter range. The effects of different parameters on the velocity and volume flow rate due to patterned hydrodynamic slippage are discussed in detail, including wave-number K, Hartmann number Ha, amplitude δ of the patterned slip length, and normalized electric field strength S. The results show that patterned slippage over microchannel walls can induce transverse flows, which will increase the mixing rates in microfluidic devices. In addition, we also find that precise flow control can be achieved by controlling the magnetic flux and the wave-number and also by well choosing the electric field intensity. Our analysis can be used for designing the efficient micro-fluidic mixers.
Lattice configurations in spin-1 Bose–Einstein condensates with the SU(3) spin–orbit coupling*
Authors: Wang Ji-Guo , Li Yue-Qing , Dong Yu-Fei
Published: August 2020

We consider the SU(3) spin–orbit coupled spin-1 Bose–Einstein condensates in a two-dimensional harmonic trap. The competition between the SU(3) spin–orbit coupling and the spin-exchange interaction results in a rich variety of lattice configurations. The ground-state phase diagram spanned by the isotropic SU(3) spin–orbit coupling and the spin–spin interaction is presented. Five ground-state phases can be identified on the phase diagram, including the plane wave phase, the stripe phase, the kagome lattice phase, the stripe-honeycomb lattice phase, and the honeycomb hexagonal lattice phase. The system undergoes a sequence of phase transitions from the rectangular lattice phase to the honeycomb hexagonal lattice phase, and to the triangular lattice phase in spin-1 Bose–Einstein condensates with anisotrpic SU(3) spin–orbit coupling.
Electrostatic switch of magnetic core-shell in 0-3 type LSMO/PZT composite film*
Authors: Chen Bo , Li Zi-Run , Huang Chuan-Fu , Zhang Yong-Mei
Published: August 2020

By dispersing La1 – x
Sr
x
MnO3 (LSMO) granule into PbZr
x
Ti1 – x
O3 (PZT) matrix, the 0-3 type LSMO/PZT composite film is synthesized through chemical solution method. The asymmetry of the top and bottom electrodes introduces novel electrostatic screening on LSMO/PZT interface. As electric polarization is switched between upward and downward orientations, the evolution of exchange bias, diode transport, and magnetoresistance is observed. The result implies the electrostatic switch of magnetic core-shell in the present film. In detail, as the spontaneous polarization is upward or downward in the PZT matrix, the ferromagnetic/antiferromagnetic or ferromagnetic/ferromagnetic core-shell structure is formed in LSMO granule, respectively. This work would develop a novel device for spintronics and metamaterial.
Optimization of terahertz monolithic integrated frequency multiplier based on trap-assisted physics model of THz Schottky barrier varactor
Authors: Qi Lu-Wei , Meng Jin , Liu Xiao-Yu , Weng Yi , Liu Zhi-Cheng , Zhang De-Hai , Zhou Jing-Tao , Jin Zhi
Published: August 2020

The optimization of high power terahertz monolithic integrated circuit (TMIC) is systemically studied based on the physical model of the Schottky barrier varactor (SBV) with interface defects and tunneling effect. An ultra-thin dielectric layer is added to describe the extra tunneling effect and the damping of thermionic emission current induced by the interface defects. Power consumption of the dielectric layer results in the decrease of capacitance modulation ration (C
max/C
min), and thus leads to poor nonlinear C–V characteristics. The proposed Schottky metal-brim (SMB) terminal structure could improve the capacitance modulation ration by reducing the influence of the interface charge and eliminating the fringing capacitance effect. Finally, a 215 GHz tripler TMIC is fabricated based on the SMB terminal structure. The output power is above 5 mW at 210–218 GHz and the maximum could exceed 10 mW at 216 GHz, which could be widely used in terahertz imaging, radiometers, and so on. This paper also provides theoretical support for the SMB structure to optimize the TMIC performance.
An improved method for the investigation of high-order harmonic generation from graphene*
Authors: Guan Zhong , Liu Lu , Wang Guo-Li , Zhao Song-Feng , Jiao Zhi-Hong , Zhou Xiao-Xin
Published: August 2020

High-order harmonic generation (HHG) of bulk crystals in strong laser field is typically investigated with semiconductor Bloch equations (SBEs). However, in the length gauge, it suffers from the divergence for the crystals with a zero band gap, such as graphene, using both Bloch- and Houston-states expansion methods. Here, we present a method of solving the SBEs based on time-dependent Bloch basis, which is equivalent to semiconductor Bloch equations in the velocity gauge. Using this method, we investigate the HHG of a single-layer graphene. It is found that our results for population are in good agreement with the other results. For a initial condition py
= 0, we find the electrons just move in single valence band or conduction band, which are in accord with classical results. Our simulations on the HHG dependence of polarization of driving laser pulse confirm that 5th, 7th, and 9th harmonic yields increase to the maximal value when laser ellipticity ε ≈ 0.3. What is more, similar to the case of atoms in the laser field, the total strength of 3rd harmonic decrease monotonically with the increase of ε. In addition, we simulate the dependence of HHG on crystallographic orientation with respect to the polarization direction of linear mid-infrared laser pulse, and the results reveal that for higher harmonics, their radiation along with the change of rotation angle θ reflects exactly the sixfold symmetry of graphene. Our method can be further used to investigate the behaviors of other materials having Dirac points (i.e., surface states of topological insulators) in the strong laser fields.
Quantum anomalous Hall effect in twisted bilayer graphene quasicrystal*
Authors: Li Zedong , Wang Z F
Published: August 2020

The nontrivial topology is investigated in a dodecagonal quasicrystal made of 30° twisted bilayer graphene (TBG). Based on tight-binding model with both exchange field and Rashba spin–orbit coupling, the topological index, chiral edge states, and quantum conductance are calculated to distinguish its unique topological phase. A high Bott index (B = 4) quantum anomalous Hall effect (QAHE) is identified in TBG quasicrystal, which is robust to a finite perturbation without closing the nontrivial gap. Most remarkably, we have found that the multiple Dirac cone replicas in TBG quasicrystal are only a spectra feature without generating extra chiral edge states. Our results not only propose a possible way to realize the QAHE in quasicrystal, but also identify the continuity of nontrivial topology in TBG between crystal and quasicrystal.
Thermal tunable one-dimensional photonic crystals containing phase change material*
Authors: Jia Yuanlin , Ren Peiwen , Fan Chunzhen
Published: August 2020

To obtain the adjustable photonic crystals (PCs), we numerically investigate one-dimensional (1D) PCs with alternating VO2 and SiO2 layers through transfer matrix method. The dispersion relation agrees well with the transmittance obtained by the finite element calculation. Tunable band gaps are achieved with the thermal stimuli of VO2, which has two crystal structures. The monoclinic crystal structure VO2 (R) at low temperature exhibits insulating property, and the high temperature square rutile structure VO2 (M) presents metal state. Concretely, the bandwidth is getting narrower and red shift occurs with the higher temperature in VO2 (R)/SiO2 PCs structure. Based on the phase change characteristics of VO2, we can flexibly adjust the original structure as VO2 (R)/VO2 (M)/SiO2. By increasing the phase ratio of VO2 (R) to VO2 (M), the band gap width gradually becomes wider and blue shift occurs. The discrete layers of gradient composites on the dispersion of 1D PCs are also investigated, which enhances the feasibility in practical operation. Thus, our proposed thermal modulation PCs structure paves a new way to realize thermal tunable optical filters and sensors.
Generation of orbital angular momentum and focused beams with tri-layer medium metamaterial*
Authors: Sun Zhi-Chao , Yan Meng-Yao , Xu Bi-Jun
Published: August 2020

We propose a metal/dielectric tri-layer metamaterial for wavefront shaping. By arranging the element in an array with a constant phase gradient and irradiated it with a plane wave, focused and focused vortex beams can be obtained. The designed metamaterial features the excellent capability of focused/focused vortex beams generation within the operating frequency range of 30 GHz–34 GHz. The simulation results are consistent with the theoretical analyses.
Performance optimization of self-powered visible photodetectors based on Cu2O/electrolyte heterojunctions
Authors: Bai Zhi-Ming , Zhang Ying-Hua , Huang Zhi-An , Gao Yu-Kun , Liu Jia
Published: August 2020

The performance of the self-powered photodetectors based on the Cu2O/electrolyte heterojunctions is optimized by adjusting morphology and structure of the Cu2O film. The Cu2O film with a deposition time of 2000 s possesses a largest current density of 559.6 μA/cm2 under visible light illumination at zero bias, with a rising time of 5.2 ms and a recovering time of 9.0 ms. This optimized Cu2O film has a highest responsivity of about 25.8 mA/W for visible light, and a negligible responsivity for UV light. The high crystallinity and excellent charge transfer property are responsible for the improved photodetection performance.
Pressure-dependent physical properties of cubic SrBO3 (B = Cr, Fe) perovskites investigated by density functional theory*
Authors: Hasan Md Zahid , Rasheduzzaman Md , Monower Hossain Khandaker
Published: August 2020

We perform the first-principles investigations of the structural, elastic, electronic, and optical properties of SrBO3 (B = Cr, Fe) perovskites under pressure based on density functional theory (DFT). This is the first detailed pressure-dependent study of the physical properties for these compounds. The calculated structural parameters are consistent with the existing experimental results and slightly decrease with the application of pressure. The mechanical properties are discussed in detail and reveal that the SrCrO3 is harder than SrFeO3. Without pressure, these compounds behave like half-metals, confirmed by their band structure and density of states. Although the SrCrO3 retains its half-metallic nature under pressure, SrFeO3 becomes metallic for both up-spin and down-spin configuration. Both charge density and bond overlap population reveal the covalent nature of Cr–O bond and Fe–O bond in the studied compounds. The optical properties of SrBO3, also discussed for the first time, reveal some interesting results.
Epitaxial synthesis and electronic properties of monolayer Pd2Se3*
Authors: Fan Peng , Zhang Rui-Zi , Qi Jing , Li En , Qian Guo-Jian , Chen Hui , Wang Dong-Fei , Zheng Qi , Wang Qin , Lin Xiao , Zhang Yu-Yang , Du Shixuan , W A Hofer , Gao Hong-Jun
Published: August 2020

Two-dimensional (2D) materials received large amount of studies because of the enormous potential in basic science and industrial applications. Monolayer Pd2Se3 is a fascinating 2D material that was predicted to possess excellent thermoelectric, electronic, transport, and optical properties. However, the fabrication of large-scale and high-quality monolayer Pd2Se3 is still challenging. Here, we report the synthesis of large-scale and high-quality monolayer Pd2Se3 on graphene-SiC (0001) by a two-step epitaxial growth. The atomic structure of Pd2Se3 was investigated by scanning tunneling microscope (STM) and confirmed by non-contact atomic force microscope (nc-AFM). Two subgroups of Se atoms have been identified by nc-AFM image in agreement with the theoretically predicted atomic structure. Scanning tunneling spectroscopy (STS) reveals a bandgap of 1.2 eV, suggesting that monolayer Pd2Se3 can be a candidate for photoelectronic applications. The atomic structure and defect levels of a single Se vacancy were also investigated. The spatial distribution of STS near the Se vacancy reveals a highly anisotropic electronic behavior. The two-step epitaxial synthesis and characterization of Pd2Se3 provide a promising platform for future investigations and applications.
Unconventional photon blockade in a three-mode system with double second-order nonlinear coupling*
Authors: Lin Hong-Yu , Yang Hui , Yao Zhi-Hai
Published: August 2020

The unconventional photon blockade (UPB) for low-frequency mode is investigated in a three-mode system with double second-order nonlinearity. By analyzing the Hamiltonian of the system, the optimal analytic condition of UPB in low-frequency mode is obtained. The numerical results are calculated by solving the master equation in a truncated Fock space, which agrees well with the analytic conditions. Through the numerical analysis of the system, it is found that the weak driving strength is favorable for the system to realize the UPB effect, and the system is insensitive to the changes of attenuation rate and environmental temperature. The comparison with the two-mode system and another similar three-mode system shows that, under similar system parameters, the UPB effect of this double two-order nonlinear system is more obvious.
Intercalation of van der Waals layered materials: A route towards engineering of electron correlation*
Authors: Niu Jingjing , Zhang Wenjie , Li Zhilin , Yang Sixian , Yan Dayu , Chen Shulin , Zhang Zhepeng , Zhang Yanfeng , Ren Xinguo , Gao Peng , Shi Youguo , Yu Dapeng , Wu Xiaosong
Published: August 2020

Being parent materials of two-dimensional (2D) crystals, van der Waals layered materials have received revived interest. In most 2D materials, the interaction between electrons is negligible. Introducing the interaction can give rise to a variety of exotic properties. Here, via intercalating a van der Waals layered compound VS2, we find evidence for electron correlation by extensive magnetic, thermal, electrical, and thermoelectric characterizations. The low temperature Sommerfeld coefficient is 64 mJ⋅K−2⋅mol−1 and the Kadowaki–Woods ratio r
KW ∼ 0.20a
0. Both supports an enhancement of the electron correlation. The temperature dependences of the resistivity and thermopower indicate an important role played by the Kondo effect. The Kondo temperature T
K is estimated to be around 8 K. Our results suggest intercalation as a potential means to engineer the electron correlation in van der Waals materials, as well as 2D materials.
Local Density of States of Quasi-Particles around a Vortex Core in a Square Superconducting Plate with a Random Impurity Potential
Authors: Tamai Takayuki , Kato Masaru
Published: August 2020

We have solved the Bogoliubov-de Gennes equation with a random impurity potential Vimp(r) under an external magnetic field with the finite element method and obtained the local density of states and the order parameter around a vortex. From these results, we find two properties of a vortex structure in a dirty superconductor. First, the order parameter structure around the vortex is deformed by the impurity potential. Second, distributions of bound states is also deformed, but these deformations of the order parameter and bound states do not correspond with each other.
Effects of artificial square nanorods array to square bulk superconducting plate
Authors: Kusafuka Takashi , Kato Masaru , Tsuchiya Yuji
Published: August 2020

It is known that the superconducting properties are improved by adding nanorods to a superconductor. As increasing nanorods into superconductor, the pinning force becomes stronger. Using the molecular dynamics method, we investigate vortex motions in a superconductor with a nanorod array. We obtain trajectories of vortices and standard deviation of vortex positions. We find peculiar temperature dependence of vortex motion.
Effects of 800 MeV Xe Irradiation on 2H-NbSe2 Single Crystals
Authors: Li Wenjie , Pyon Sunseng , Takahashi Ayumu , Miyawaki Daisuke , Kobayashi Yuto , Tamegai Tsuyoshi
Published: August 2020

Effects of artificial defects on 2H-NbSe2 single crystals introduced by 800 MeV Xe irradiation with a dose equivalent matching field B
Φ up to 8 T were studied. The bulk magnetization measurements performed by a commercial SQUID magnetometer reveal strong enhancement of critical current density in NbSe2 after introducing defects by 800 MeV Xe irradiation. T
c is found to be robust against the 800 MeV Xe irradiation, while c-axis lattice parameter shows an obvious increase with increasing B
Φ.
Evaluation of the physical properties and the real space observation in 2H-TaS2 synthesized with flux method
Authors: Ohta S , Kobayashi S , Nomura A , Fujisawa Y , Demura S , Sakata H
Published: August 2020

Single crystal of 2H-TaS2 was synthesized with flux method using the flux in which alkali metal ions were included. Analysis of the composition and the structure by EDX measurements and X-Ray diffraction showed that the hydrates of potassium ion were intercalated in 2H-TaS2 synthesized with NaCl/KCl flux. The local intercalation was confirmed by the observation of the superstructures with the period of 2a0 × 2a0 or √3a0 × √3a0 by scanning tunnelling microscopy measurements.