bluuebunny/crossref_metadata_2025 huggingface dataset:
La place de la Société du Canal de Provence dans le partage de l’eau en Provence
Authors: Randrianasolo Annie , Casteigts Catherine , Brun Jean-François , Grawitz Bruno , Moreau Benoit
Published: May 2022

Le partage de l’eau abordé dans cet article se concentre principalement sur le système Durance-Verdon alimentant directement la concession régionale de la Société du Canal de Provence. Ces rivières constituent également les principales ressources en eau superficielles de la Provence. Le système est composé d’infrastructures hydrauliques importantes : d’abord de stockage sur la Durance amont (Serre-Ponçon) et sur le Verdon amont (Castillon et Sainte-Croix), ensuite de transfert vers le reste de la Région, notamment sur les zones littorales méditerranéennes fortement peuplées. Les grandes retenues en amont du bassin sont en grande partie sous la concession d’EDF, la SCP étant concessionnaire du canal de Provence, dont les ressources en eau sont principalement issues du Verdon. La SCP a la responsabilité de l’acheminement et de la distribution des eaux dans toute la Région PACA jusque dans les Alpes-Maritimes. Dans sa gestion quotidienne de la ressource en eau, la SCP veille à une gestion rationnelle de la ressource et est tournée vers l’économie d’eau afin de se prémunir au mieux du changement climatique et de ses incertitudes.
Post-TIPS Hepatic Encephalopathy
Authors: Maleux Geert , Laleman Wim , Bonne Lawrence , Buyck Pieter-Jan , Nevens Frederik
Published: May 2022

Transjugular intrahepatic portosystemic shunt (TIPS) procedures may be complicated by hepatic encephalopathy related to excessive shunting of portal venous blood into the systemic circulation without detoxification by the liver parenchyma. Although liver transplantation is the only curative treatment option, only a few patients can benefit from this procedure. In a first step, medical, conservative management is performed. In case of hepatic encephalopathy, refractory to medical management, several interventional techniques are available to reduce the diameter of the TIPS and subsequently, to reduce the volume of shunted portal venous blood. Technical aspects, devices and outcome results of these reduction procedures will be discussed as well as preventive procedures and devices which can be used during initial TIPS procedures.
Non-pharmacological Interventions for Improving Sleep Quality During Pregnancy: A Systematic Review and Meta-Analysis
Authors: Paulino Daiane Sofia Morais , Borrelli Carolina Bicudo , Faria-Schützer Débora Bicudo , Brito Luiz Gustavo Oliveira , Surita Fernanda Garanhani
Published: May 2022

Objective To investigate the effect of non-pharmacological interventions to improve sleep quality during pregnancy.

Data sources A search was made in the NCBI/PubMed, ClinicalTrials.gov, Embase, BVS, and Web of Science databases. There were no limitations regarding language, sample size, and type of non-pharmacological intervention. We have included prospective clinical trials between July 2014 and July 2019.

Selection of studies This study was registered in the Prospective International Registration of Systematic Reviews (PROSPERO) database was performed. Publication bias was also assessed with funnel plots. the primary outcome was the total score in the Pittsburgh Sleep Quality Index (PSQI) before and after intervention. Risk of bias and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria were used for assessing methodological quality. From the 28 retrieved studies, we have selected 8 for qualitative analysis and 6 for meta-analysis.

Data collection Two independent reviewers performed the study selection. In the case of disagreement, a third senior reviewer was consulted. The study was initially assessed based on the title, followed by abstract. Lastly, the full text was assessed to be included.

Data Synthesis A significant improvement on the sleep quality (PSQI score) was observed when all interventions were grouped (MD = -3.03, 95%CI -4.15 to -1.92, n = 623, i2 = 84%, p < 0.001). Analysis by subgroup (music listening: MD = -1.96, 95% CI -3.27 to -0.65, n = 207, i2 = 67%, p = 0.003 and other interventions: MD = -3.66, 95% CI -4.93 to -2.40, n = 416, i2 = 80%, p < 0.001) showed an improvement, with high heterogeneity. Risk of bias has shown performance and detection bias for almost studies, and GRADE evidence was very low for all analyzed variables.

Conclusion Non-pharmacological interventions—listening to music, physical exercise, relaxation exercises, lettuce seed, sleep hygiene, and acupressure—are effective for improving sleep quality during pregnancy.
The impact of COVID-19 on digital communication patterns
Authors: DeFilippis Evan , Impink Stephen Michael , Singell Madison , Polzer Jeffrey T. , Sadun Raffaella
Published: May 2022

We explore the impact of COVID-19 on employees’ digital communication patterns through an event study of lockdowns in 16 large metropolitan areas in North America, Europe, and the Middle East. Using de-identified, aggregated meeting and email meta-data from 3,143,270 users, we find, compared to pre-pandemic levels, increases in the number of meetings per person (+12.9 percent) and the number of attendees per meeting (+13.5 percent), but decreases in the average length of meetings (−20.1 percent). Collectively, the net effect is that people spent less time in meetings per day (−11.5 percent) in the post-lockdown period. We also find significant and durable increases in length of the average workday (+8.2 percent, or +48.5 min), along with short-term increases in email activity. These findings provide insight into how formal communication patterns have changed for a large sample of knowledge workers in major cities. We discuss these changes in light of the ongoing challenges faced by organizations and workers struggling to adapt and perform in the face of a global pandemic.
Ferroelectric polymers for neuromorphic computing
Authors: Niu Xuezhong , Tian Bobo , Zhu Qiuxiang , Dkhil Brahim , Duan Chungang
Published: May 2022

The last few decades have witnessed the rapid development of electronic computers relying on von Neumann architecture. However, due to the spatial separation of the memory unit from the computing processor, continuous data movements between them result in intensive time and energy consumptions, which unfortunately hinder the further development of modern computers. Inspired by biological brain, the in situ computing of memristor architectures, which has long been considered to hold unprecedented potential to solve the von Neumann bottleneck, provides an alternative network paradigm for the next-generation electronics. Among the materials for designing memristors, i.e., nonvolatile memories with multistate tunable resistances, ferroelectric polymers have drawn much research interest due to intrinsic analog switching property and excellent flexibility. In this review, recent advances on artificial synapses based on solution-processed ferroelectric polymers are discussed. The relationship between materials' properties, structural design, switching mechanisms, and systematic applications is revealed. We first introduce the commonly used ferroelectric polymers. Afterward, device structures and the switching mechanisms underlying ferroelectric synapse are discussed. The current applications of organic ferroelectric synapses in advanced neuromorphic systems are also summarized. Eventually, the remaining challenges and some strategies to eliminate non-ideality of synaptic devices are analyzed.
Sensitive control of broad-area semiconductor lasers by cavity shape
Authors: Kim Kyungduk , Bittner Stefan , Jin Yuhao , Zeng Yongquan , Guazzotti Stefano , Hess Ortwin , Wang Qi Jie , Cao Hui
Published: May 2022

The ray dynamics of optical cavities exhibits bifurcation points: special geometries at which ray trajectories switch abruptly between stable and unstable. A prominent example is the Fabry–Perot cavity with two planar mirrors, which is widely employed for broad-area semiconductor lasers. Such cavities support lasing in a relatively small number of transverse modes, and the laser is highly susceptible to filamentation and irregular pulsations. Here, we demonstrate experimentally that a slight deviation from this bifurcation point (planar cavity) dramatically changes the laser performance. In a near-planar cavity with two concave mirrors, the number of transverse lasing modes increases drastically. While the spatial coherence of the laser emission is reduced, the divergence angle of the output beam remains relatively narrow. Moreover, the spatiotemporal lasing dynamics becomes significantly more stable compared to that in a Fabry–Perot cavity. Our near-planar broad-area semiconductor laser has higher brightness, better directionality, and hence allows shorter integration times than an incandescent lamp while featuring sufficiently low speckle contrast at the same time, making it a vastly superior light source for speckle-free imaging. Furthermore, our method of controlling spatiotemporal dynamics with extreme sensitivity near a bifurcation point may be applied to other types of high-power lasers and nonlinear dynamic systems.
Oceans of Plastic
Authors: Gray Tracey
Published: May 2022

Our oceans are amazing! They are filled with wonderful sea creatures and are essential for a healthy planet. But it’s now estimated that there are more pieces of plastic in the ocean than visible stars in the Milky Way. So how can we stop plastic from our homes and cities from ending up floating in oceans far away? By becoming ocean change-makers!

Oceans of Plastic explores how ocean systems and swirling currents bring plastics together into massive ocean garbage patches. It also uncovers the floating world of the 'plastisphere' – a mini community of microbes living on ocean plastics – and explains how plastic breaks up, not down, and can even end up on your dinner plate!

Oceans of Plastic is packed with great ideas and simple changes that you can make to help our oceans. Become an ocean change-maker in your home, school or community, and inspire others to join you in protecting the future of our oceans.

Reading level varies from child to child, but we recommend this book for ages 9 to 12.
Zinc finger protein 280C contributes to colorectal tumorigenesis by maintaining epigenetic repression at H3K27me3-marked loci
Authors: Ying Ying , Wang Maolin , Chen Yongheng , Li Meiqi , Ma Canjie , Zhang Junbao , Huang Xiaoyan , Jia Min , Zeng Junhui , Wang Yejun , Li Lili , Wang Xiaomei , Tao Qian , Shu Xing-sheng
Published: May 2022

Significance

This study uncovered the role of ZNF280C, a known DNA damage response protein, as a tumorigenic transcription regulator that contributes to colorectal tumorigenesis and metastasis through maintaining an epigenetic repression program at key cancer gene loci. These findings identified a contributor with potential prognostic value to colorectal pathogenesis and provide mechanistic insight to the essential function of transcription factor in fine-tuning the activity of chromatin regulators for proper transcription control.
Enhanced spatial resolution in magnetic resonance imaging by dynamic nuclear polarization at 5 K
Authors: Chen Hsueh-Ying , Wilson C. Blake , Tycko Robert
Published: May 2022

Significance

Although MRI is a powerful method for visualizing features within organisms and materials, the relatively low signal-to-noise ratio (SNR) of the NMR signals that are used to construct an image makes MRI with isotropic spatial resolution below 3.0 μm impractical at room temperature. Here we show that SNR enhancements available from a combination of low temperatures and dynamic nuclear polarization allow MRI with 1.7-μm isotropic resolution. These results may enable informative MRI studies of eukaryotic cells, cell clusters, and small tissue samples.
Aerosol particle emission increases exponentially above moderate exercise intensity resulting in superemission during maximal exercise
Authors: Mutsch Benedikt , Heiber Marie , Grätz Felix , Hain Rainer , Schönfelder Martin , Kaps Stephanie , Schranner Daniela , Kähler Christian J. , Wackerhage Henning
Published: May 2022

Significance

Airborne transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or other pathogens is probably increased during indoor exercise, but data on the emission of aerosol particles by an exercising individual are lacking. Here, we report that aerosol particle emission increases on average 132-fold from 580 ± 489 particles/min at rest to 76,200 ± 48,000 particles/min during maximal exercise. Aerosol particle emission increases moderately up to an exercise intensity of ≈2 W/kg and exponentially at higher exercise intensities. These data not only explain SARS-CoV-2 transmissions during indoor group exercise but also can be used to design better targeted mitigation measures for physical activity indoors such as physical education in school, dance events during weddings, or high-intensity gym classes such as spinning.
Evaluating audio description and emotional engagement for BPS visitors in a museum context
Authors: Wang Xi , Crookes Danny , Harding Sue-Ann , Johnston David
Published: May 2022

Museums face a particular challenge in enabling blind and partially sighted (BPS) visitors to engage emotionally with the narrative(s) they present. In collaboration with a world-leading tourist attraction (Titanic Belfast) and the Royal National Institute of Blind People (RNIB), we have applied several different approaches for improving emotional engagement for BPS visitors. This paper addresses the critical challenge of how to obtain reliable evidence for evaluating the emotional response of BPS visitors to the museum’s audio description (AD) and overall experience. We consider six different methods for measuring emotional engagement, and consider their potential for providing reliable experimental evidence. Based on BPS-user feedback, we present a qualitative comparison of these methods, uniquely all applied to the same museum context.
Effect of external load on muscle activation during the barbell back squat
Authors: Martinez Sarah C. , Coons John M. , Mehls Kelton D.
Published: May 2022

The aim of this study was to compare gluteus maximus‐to‐hamstring (GM:H) co‐activation, hamstrings‐to‐quadriceps (H:Q) co‐activation, and mean muscle activity in the vastus lateralis (VL), vastus medialis (VM), rectus femoris (RM), gluteus maximus (GM), semitendinosus (ST), and bicep femoris (BF) muscles across a range of training loads (40%, 50%, 50%, 70%, 80% 90% 1RM) of the barbell back squat in resistance trained females. Surface electromyography (EMG) was observed in 18 healthy resistance trained females for the VL, VM, RM, GM, ST, and BF during the ascending and descending phase of the back squat. During the ascending phase, the VL, VM, RM, GM, ST, and BF displayed significantly more EMG activation at 90% 1RM compared to 40%–70% (p < .03). During the descending phase, there were no significant differences displayed in mean muscle activity at 40%–80% of 1RM compared to 90% of 1RM. There were no significant differences in H‐Q co‐activation and GM‐H co‐activation during the ascending or descending phase across external loads. These findings are similar to the results found in similar studies using male participants and support that higher training intensities (80%–90% 1RM) of the barbell back squat significantly activate muscles surrounding the hip compared to lower loads (40%–70%). The results of this study also suggest that training intensities of 80% 1RM and 90% 1RM elicits the similar musculature activation in the muscle surrounding the hip in resistance trained females.

Highlights

During the back squat, mean muscle activity of the hip and leg muscles increased linearly with exercise intensity (40%–90% of one‐repetition max) in resistance trained females.

No significant difference in mean activity were noted between 80% and 90% of one‐repetition max during the ascending and descending phases.

During the ascending phase, 80% of one‐repetition max generated the highest gluteus maximus to hamstring activity co‐activation ratio.

During the descending phase, 40% of one‐repetition max produced a gluteus maximus to hamstring activity co‐activation ratio closest to 1.0.
Application of the Lagrange-mesh method in continuum-discretized coupled-channel calculations
Authors: Chen Wendi , Guo Hairui , Ye Tao , Ying Yangjun , Sun Weili , Han Yinlu
Published: May 2022

We apply the Lagrange-mesh method to discretize continuum states of weakly bound nuclei for continuum-discretized coupled-channel (CDCC) calculations of three-body breakup reactions. This discretization method is compared with the bin method, which is regarded as the standard continuum discretization method, for the d and 6Li induced reactions. An improved Numerov algorithm is used to solve the coupled channels equations, which permits a fast integration of equations and a convenient treatment of the closed channels. A new CDCC model code named CDCC-R is developed. In all cases, the combination of the Lagrange-mesh method and the Numerov algorithm shows high efficiency and accuracy for the CDCC calculations of the elastic scattering and breakup reactions. Especially, various numerical and physical aspects are discussed for 6Li induced reactions. The coupling effects of the continuum states with high orbital angular momentum and closed channels are discussed. Moderate effects are found in the calculations for elastic scattering and breakup reaction when F- and G-wave continuum states are included in CDCC model space for 6Li induced reactions at the incident energies well above the Coulomb barrier. The closed channel effect is found to be indispensable for 6Li breakup reaction calculation when the incident energy is around the Coulomb barrier.
CTA sensitivity on TeV scale dark matter models with complementary limits from direct detection
Authors: Duangchan C. , Pongkitivanichkul C. , Uttayarat P. , Jardin-Blicq A. , Wechakama M. , Klangburam T. , Treesukrat W. , Samart D. , Sawangwit U. , Aguirre-Santaella A. , Sánchez-Conde M.A.
Published: May 2022

With ever increasing pressure from collider physics and direct detection experiments, particle physics models of TeV scale dark matter are gaining more attention. In this work, we consider two realizations of the class of scalar portal dark matter scenarios — the inverse seesaw model and the inert doublet model. Observations by the Cherenkov Telescope Array (CTA) of very-high-energy γ rays from dark matter annihilation in the context of these models are simulated for the Draco and Sculptor dwarf spheroidal galaxies, and later analyzed using ctools. We study the potential of CTA for the 5σ detection of a dark matter annihilation signal.
In the absence of a signal, we also derive the 2σ upper limits on the annihilation cross-section. We compare our projected CTA sensitivity against the projected sensitivity of the next generation of direct detection experiment, i.e. XENONnT. Although the limits from CTA are significantly improved compared with the previous generations of γ-ray experiments, they are still ∼2 orders of magnitude above the thermal relic cross-section for the considered targets. In the case of the inverse seesaw model, the constraint from the future direct detection experiment XENONnT is much weaker than the CTA sensitivity, whereas for the inert doublet model, XENONnT gives a bound an order of magnitude stronger compared to the CTA limits.
Enhanced multicolor optomechanically induced transparency in electro-optical hybrid system
Authors: Pan Guixia , Xiao Ruijie , Zhai Chengbo
Published: May 2022

We investigate the tunable multicolor optomechanically induced transparency through electro-optical hybrid system. The system consists an optical cavity fulled with three-level atomic ensemble and two charged mechanical oscillators coupled via Coulomb interaction. Under different coupling strengths, the system can exhibit the phenomena of optomechanical induced transparency increase. Specifically, the number of the transparency windows increases with the presence of charged mechanical resonators and atoms. Furthermore, the induced transparency phenomena are strongly manipulated by the coupling strength between the optical mode and the mechanical mode, or between the optical mode and the atoms and the Rabi frequency, or between the Coulomb coupling between the two charged mechanical modes. It is found that the larger coupling strength between the cavity field and the atoms and the mechanical oscillator, the wider transparent windows. Our approach is feasible for storage of light and has potential applications in quantum information processing.
Density fluctuations of two-dimensional active-passive mixtures
Authors: Zhang Jian , Huang Tao , Xu Guoqing , Chen Yong
Published: May 2022

Dimension-dependent giant density fluctuations are a typical feature of active matter systems. In this work, we study the density fluctuation in two-dimensional mixtures of active and passive particles by Brownian dynamics simulations. The boundary of motility-induced phase separation is determined by the transition from unimodal to bimodal density distribution. A rapid increase of the fluctuation exponent near the boundary of phase separation in the plane of density and Péclet number was observed. When phase separation occurs, the fluctuation exponent is an approximate constant of

0.85
.
Longitudinal conductivity in ABC-stacked trilayer graphene under irradiating of linearly polarized light
Authors: Zhu Guo-Bao , Yang Hui-Min , Yang Jie
Published: May 2022

We study the effect of linearly polarized light on the band structure and longitudinal conductivity in ABC-stacked trilayer graphene. The linearly polarized light can induce a pair of additional points in ABC-stacked trilayer graphene, where conduct and valence bands touch. The locations of these points are determined by the amplitude of the light. Furthermore, the layer pseudospin polarization can be controlled by the light. When the Fermi energy locates at Dirac points, i.e., E
f = 0, the longitudinal conductivity shows resonance phenomena when the light is present. Away from the Dirac points, the longitudinal conductivity is unchanged as varying E
f for weak light field at larger Fermi energy, and the amplitude of longitudinal conductivity can be controlled by tuning the light field amplitude. Moreover, the effect of linearly polarized light on resonance phenomena in k-cubic Rashba–Dresselhaus system under the irradiating of linearly polarized light is discussed.
Influence of magnetic field on power deposition in high magnetic field helicon experiment
Authors: Zhou Yan , Ji Peiyu , Li Maoyang , Zhuge Lanjian , Wu Xuemei
Published: May 2022

Based on high magnetic field helicon experiment (HMHX), HELIC code was used to study the effect of different magnetic fields on the power deposition under parabolic distribution. This paper is divided into three parts: preliminary calculation, actual discharge experiment and calculation. The results of preliminary calculation show that a magnetic field that is too small or too large cannot produce a good power deposition effect. When the magnetic field strength is 1200 Gs, a better power deposition can be obtained. The actual discharge experiment illustrates that the change of the magnetic field will have a certain influence on the discharge phenomenon. Finally, the results of verification calculation successfully verify the accuracy of the results of preliminary simulation. The results show that in the actual discharge experiment, it can achieve the best deposition effect when the magnetic field is 1185 Gs.
Weak localization in disordered spin-1 chiral fermions
Authors: Miao Shaopeng , Tu Daifeng , Zhou Jianhui
Published: May 2022

We theoretically investigate the quantum interference theory of magnetotransport of the three-component or spin-1 chiral fermions, which possess two linear Dirac bands and a flat band. For isotropic scalar impurities, the correction of conductivity from the coherent backscatter and non-coherent backscatter contributions cancel out in the intravalley scattering, leading to a weak localization correction to the Drude conductivity from the intervalley scattering. For the anisotropic impurities, the above cancelation is removed, we find the approximative quantum interference conductivity in the weak anisotropy case. The contributions from the chiral anomaly and classical Lorentz force are also discussed. Our work reveals some intriguing and detectable transport signatures of the novel spin-1 chiral fermions.
Localized nonlinear waves in a myelinated nerve fiber with self-excitable membrane
Authors: Nfor Nkeh Oma , Ghomsi Patrick Guemkam , Moukam Kakmeni Francois Marie
Published: May 2022

We systematically study the evolution of modulated nerve impulses in a myelinated nerve fiber, where both the ionic current and membrane capacitance provide the necessary nonlinear feedbacks. This is achieved by using a perturbation technique, in which the Liénard form of the modified discrete Fitzhugh–Nagumo equation is reduced to the complex Ginzburg–Landau amplitude equation. Three distinct values of the capacitive feedback parameter are considered. At the critical value of the capacitive feedback parameter, it is shown that the dynamics of the system is governed by the dissipative nonlinear Schrödinger equation. Linear stability analysis of the system depicts the instability of plane waves, which is manifested as burst of modulated nerve impulses that fulfills the Benjamin–Feir criteria. Variations of the capacitive feedback parameter generally influences the plane wave stability and hence the type of wave profile identified in the neural network. Results of numerical simulations mainly confirm the propagation, collision, and annihilation of nerve impulses in the myelinated axon.
Precisely controlling the twist angle of epitaxial MoS2/graphene heterostructure by AFM tip manipulation
Authors: Yuan Jiahao , Liao Mengzhou , Huang Zhiheng , Tian Jinpeng , Chu Yanbang , Du Luojun , Yang Wei , Shi Dongxia , Yang Rong , Zhang Guangyu
Published: May 2022

Two-dimensional (2D) moiré materials have attracted a lot of attention and opened a new research frontier of twistronics due to their novel physical properties. Although great progress has been achieved, the inability to precisely and reproducibly manipulate the twist angle hinders the further development of twistronics. Here, we demonstrated an atomic force microscope (AFM) tip manipulation method to control the interlayer twist angle of epitaxial MoS2/graphene heterostructure with an ultra-high accuracy better than 0.1°. Furthermore, conductive AFM and spectroscopic characterizations were conducted to show the effects of the twist angle on moiré pattern wavelength, phonons and excitons. Our work provides a technique to precisely control the twist angle of 2D moiré materials, enabling the possibility to establish the phase diagrams of moiré physics with twist angle.
Yb:CaF2–YF3 transparent ceramics ultrafast laser at dual gain lines
Authors: Liu Xiao-Qin , Hao Qian-Qian , Liu Jie , Liu Dan-Hua , Li Wei-Wei , Su Liang-Bi
Published: May 2022

Yb3+:CaF2–YF3 transparent ceramics with excellent optical quality was successfully fabricated by hot-pressed method. Pulsed laser properties of this ceramics were investigated for the first time. Laser diode (LD) was applied as the pump source to generate a dual-wavelength mode-locked (ML) laser. The maximum average output power was 310 mW, which represents the highest output power of ultrafast calcium fluoride ceramic laser. The spectrum separated at 1048.9 nm and 1049.7 nm with a total pulse duration of 8.9 ps. The interval period between the beating signals was about 4.3 ps, corresponding to a 0.23 THz beat pulse repetition rate. These results demonstrate its potential in producing dual-wavelength ultrashort pulses. These Yb3+:CaF2–YF3 ceramics with low-cost and short-preparation period are ideal candidate materials for ultrafast lasers.
Effect of f–c hybridization on the γ → α phase transition of cerium studied by lanthanum doping
Authors: Wang Yong-Huan , Zhang Yun , Liu Yu , Tan Xiao , Ma Ce , Wang Yue-Chao , Zhang Qiang , Yuan Deng-Peng , Jian Dan , Wu Jian , Lai Chao , Wang Xi-Yang , Luo Xue-Bing , Chen Qiu-Yun , Feng Wei , Liu Qin , Hao Qun-Qing , Liu Yi , Tan Shi-Yong , Zhu Xie-Gang , Song Hai-Feng , Lai Xin-Chun
Published: May 2022

The hybridization between the localized 4f level (f) with conduction (c) electrons in γ-Ce upon cooling has been previously revealed in single crystalline thin films experimentally and theoretically, whereas its influence on the γ → α phase transition was not explicitly verified, due to the fact that the phase transition happened in the bulk-layer, leaving the surface in the γ phase. Here in our work, we circumvent this issue by investigating the effect of alloying addition of La on Ce, by means of crystal structure, electronic transport and angle resolved photoemission spectroscopy measurements, together with a phenomenological periodic Anderson model and a modified Anderson impurity model. Our current researches indicate that the weakening of f–c hybridization is the major factor in the suppression of γ → α phase transition by La doping. The consistency of our results with the effects of other rare earth and actinide alloying additions on the γ → α phase transition of Ce is also discussed. Our work demonstrates the importance of the interaction between f and c electrons in understanding the unconventional phase transition in Ce, which is intuitive for further researches on other rare earth and actinide metals and alloys with similar phase transition behaviors.
Numerical simulation on dendritic growth of Al–Cu alloy under convection based on the cellular automaton lattice Boltzmann method
Authors: Wang Kang-Wei , Wu Meng-Wu , Tian Bing-Hui , Xiong Shou-Mei
Published: May 2022

A numerical model is developed by coupling the cellular automaton (CA) method and the lattice Boltzmann method (LBM) to simulate the dendritic growth of Al–Cu alloy in both two and three dimensions. An improved decentered square algorithm is proposed to overcome the artificial anisotropy induced by the CA cells and to realize simulation of dendritic growth with arbitrary orientations. Based on the established CA-LBM model, effects of forced convection and gravity-driven natural convection on dendritic growth are studied. The simulation results show that the blocking effect of dendrites on melt flow is advanced with a larger number of seeds. The competitive growth of the converging columnar dendrites is determined by the interaction between heat flow and forced convection. Gravity-driven natural convection leads to highly asymmetric growth of equiaxed dendrites. With sinking downwards of the heavy solute, chimney-like or mushroom-like solute plumes are formed in the melt in front of the columnar dendrites when they grow along the gravitational direction. More details on dendritic growth of Al–Cu alloy under convection are revealed by 3D simulations.
Kondo screening cloud in a superconductor with mixed s-wave and p-wave pairing states
Authors: Huang Zhen-Zhen , Peng Xiong-Tao , Wang Wan-Sheng , Sun Jin-Hua
Published: May 2022

We study the Kondo screening of a spin-1/2 magnetic impurity coupled to a superconductor, which is fabricated by combination of an s-wave superconductor, a ferromagnet and a semiconductor with Rashba spin–orbit coupling (RSOC). The proximity induced superconducting states include the s-wave and p-wave pairing components with the aids of RSOC, and the ferromagnet induces a Zeeman field which removes the spin degeneracy of the quasiparticles in the triplet states. Thus, the Kondo screening of magnetic impurity involves the orbital degrees of freedom, and is also affected by the Zeeman field. Using the variational method, we calculate the binding energy and the spin–spin correlation between the magnetic impurity and the electrons in the coexisting s-wave and p-wave pairing states. We find that Kondo singlet forms more easily with stronger RSOC, but Zeeman field in general decreases the binding energy. The spin–spin correlation decays fast in the vicinity of the magnetic impurity. Due to the RSOC, the spatial spin–spin correlation becomes highly anisotropic, and the Zeeman field can induce extra asymmetry to the off-diagonal components of the spin–spin correlation. Our study can offer some insights into the studies of extrinsic topological superconductors fabricated from the hybrid structures containing chains of magnetic impurities.
A novel natural surface-enhanced fluorescence system based on reed leaf as substrate for crystal violet trace detection
Authors: Cao Hui-Ju , Cao Hong-Wen , Li Yue , Sun Zhen , Yang Yun-Fan , Jiao Ti-Feng , Wang Ming-Li
Published: May 2022

The preparation of surface-enhanced fluorescence (SEF) substrates is often influenced by experimental strategies and factors such as the morphology and size of the nanostructures. In this study, using the natural reed leaves (RLs) without any special pretreatment as the substrate, metal silver is modified by magnetron sputtering technology to prepare a stable and efficient SEF system. The abundant “hedgehog-like” protrusions on the RL substrate surface can generate high-density “hot spots”, thus enhancement factor (EF) is enhanced up to 3345 times. The stability and reproducibility are verified in many measurements. The contribution of the intervention of silver nanostructure to the radiation attenuation process of fluorescent molecules is analyzed with the aid of Jablonski diagrams. Three-dimensional (3D) finite difference time domain (FDTD) simulates the spatial electric field and “hot spots” distribution of the substrate. The “hedgehog-like” protrusion structure generates multiple “hot spots”, which produce an excellent local surface plasmon resonance (LSPR) effect and provide higher fluorescence signal. Finally, RL/Ag-35 substrate is used to detect crystal violet (CV), and the detection limit is as low as 10−13 M. This “hedgehog-like” SEF substrate provides a new strategy for the trace detection of CV, which has a good practical application value.
On Magnetic-coupled Matrix Rectifier Applied to Accelerator Power Supply
Authors: Wang Bin , Si Yang , Zhou Zhiwen
Published: May 2022

The power supply designing of superconducting magnet is vital for magnetic field system in the development of accelerator. Magnet power supply can still be improved in grid-side power factor, and better cost-effective solutions can be sought. For release or consumption of the huge energy stored in the future superconducting magnet, so that it is urgent to carry out related research to solve the energy feedback problem. Utilizing the characteristics of adjustable power factor and bi-directional energy transfer of matrix converter, a novel magnetic-coupled matrix rectifier topology is presented, which is suitable for accelerator power supply. An improved control strategy is proposed to realize sinusoidal waveform of input current, unity input power factor as well as output current tracking the instruction current waveform. Prototype test shows that the matrix converter can realize DC output and the control strategy can achieve expected requirements. Load disturbance experiment of quasi-trapezoidal wave output is preliminarily verified. The matrix converter studied in the paper, as a kind of feasible attractive choice of accelerator power converter topology, has a favorable research prospect.
CFAR Detector Based on the Identification of Sea Clutter Distribution Characteristics
Authors: Li Bowen , Liu Xiaoming , Du Shasha , Li Wanhan
Published: May 2022

To improve the capability of radar detection in a time-varying maritime environment, an algorithm was proposed and analyzed in this paper that can be applied to determine the shape and scale parameters of the K-distributed model using the radar parameters and environmental information under the context of K-distributed sea clutter, and improved the original algorithm to improve the accuracy of the parameter estimation algorithm. Furthermore, a CFAR detector capable of identifying the characteristics of sea clutter distribution was developed. It can estimate the parameters of K-distributed model for sea clutter in real time using both radar parameters and environmental perception information, thus improving the accuracy of clutter background estimation. When the false alarm rate reaches a certain level, the adaptive threshold factor can be obtained for the CFAR detector proposed in this paper, thus improving the effectiveness of control on the CFAR detector. As suggested by the simulation results, the proposed method outperforms the CFAR detector with fixed parameters in the capability of detection and robustness under the context of K-distributed clutter.
Design of high voltage electrostatic protection device for CAN bus
Authors: Su Xuebing , Wang Yang , Jin Xiangliang , Yang Hongjiao
Published: May 2022

The Dual-Direction Silicon Controlled Rectifier (DDSCR) device has dual-direction electrostatic protection function and strong current discharging ability, which is widely used in ESD on-chip protection. In this paper, a high performance symmetric high voltage Dual-Direction Silicon Controlled Rectifier with floating P+ (HVDDSCR_FP+) is designed for CAN bus under 0.18 μm BCD process. In order to predict and verify the ESD performance of the device, TCAD two-dimensional device simulation and Transmission Line Pulse (TLP) test system were used. The experimental results show that the HVDDSCR_FP + structure has not only symmetrical positive and reverse I-V curves, but also the characteristics of high holding voltage and high failure current. Compared with the traditional HVDDSCR, HVDDSCR_FP+, at 25V forward and reverse trigger voltages (Vt), has increased its holding voltage (Vh) from 12V to 20V, failure current (It2) from 5A to 35A. In the actual tape-out process, it is found that the width of the N-well has a great influence on the performance of the device. After analyzing the reason and improving it, the leakage current of the device is reduced from μA level to nA level.
Transformer evaluation strategy based on improved machine learning
Authors: Wu Tianyi , Xu Xiangyi , Chen Lu , Tang Weijie
Published: May 2022

A transformer state assessment method based on an improved extreme learning machine is proposed in this paper, which introduces an adaptive evolution algorithm into the extreme learning machine. This method is used in the evaluation model to evaluate the state of the transformer. The algorithm is trained and tested through sample sets. Furthermore, the test results are analyzed to prove the feasibility of the proposed control strategy.
Innovative Techniques in Comparator Designs
Authors: Chen Yiming
Published: May 2022

This paper presents four innovative designs of comparators proposed these years. A latch-type dynamic bias adds a tail capacitor to prevent fully discharging at the pre-amplifier output nodes to reduce energy consumption. The comparator is analysed and then compared with floating inverter amplifier (FIA) type. The pre-amplifier of the FIA type adopts an inverter-based input pair by a floating reservoir capacitor, greatly boosting gm/Id and improving the energy efficiency. The edge-pursuit comparator (EPC) provides a new perspective when designing comparators. According to the input difference, it will automatically adjust the comparison energy, avoiding wasting unnecessary energy spent on coarse comparison. Finally, for the edge-race comparator (ERC), it further improves the performance of saving energy and addressing the relatively long comparison time in the EPC.
A Study on Design and Optimization methods in Latch Type Comparator
Authors: Chen Ziyan , Yang Zun
Published: May 2022

The current state-of-the-art communication systems require analog-to-digital converters (ADCs) to sample the analog signals in digital representation at high speed and low power consumption with very high accuracy. Performance demand for ADCs directly promote the advancement of their basic component - the comparator. The traditional Strong-Arm dynamic comparator has been widely accepted for its fast decision, but it is limited by its significant voltage headroom and kickback noise. The double-tail latched dynamic comparator mitigates the aforementioned problems by allowing separate stages for the pre-amplifier and the latch so that it can have near- operation. However, energy consumption and propagation delay are still problems to be solved. In this article, we present a review of the recent improvements for the dynamic comparator architecture. The advantages and disadvantages of these techniques are also illustrated with simulation and measurement results.
Theoretical study of the discharge decomposition mechanism of environment-friendly insulation gas HFO-1234ze(E) in the presence of trace water
Authors: Gan Hui , Wang Feng , Zhong Lipeng , Liu Jie , Hai Bin , Tang Nian , Li Li
Published: May 2022

HFO-1234ze(E) has excellent insulating and environmental properties, but its discharge decomposition mechanism in the presence of trace water is still unclear. Based on the density functional theory (DFT), the discharge decomposition characteristics of HFO-1234ze(E) in the presence of trace water were analyzed at the B3LYP/6-311+G(d,p) level. The results show that in the presence of trace water, HFO-1234ze(E) will decompose and generate H2, HF, CH≡CF, CH≡CH, CF3OH, CF3H, CF4, C2F6, CF2O, CH2=CHF and CHF2CH3. By analyzing the ionization parameters of the main decomposition products, it can be found that the dielectric strengths of most of the products were lower than that of HFO-1234ze(E). Among the products, CF3H, CF4 and C2F6 are hazardous to the environment, while CH2=CHF, CHF2CH3 and CF2O are flammable or toxic, which may endanger the safety of staff. Therefore, water should be avoided when HFO-1234ze(E) is used as the insulating medium.
The Influence of Novel Power System Characteristics on 330kV Power Grid Short-circuit Current
Authors: Yuan Xingzhong , Wang Zhe , Yan Huan , Yan Na , Sun Yi , Xu Yiqing
Published: May 2022

Under the development goal of “Carbon Peak, Carbon Neutralization”, the concept of novel power system is proposed. Its representative features include AC/DC interconnection of power grid and large-scale access of new energy power stations. Under these characteristics, higher requirements are put forward for the short-circuit current breaking capacity of the circuit breaker. The DC component of short-circuit current and the injection of new energy into the system short-circuit current cannot be ignored. Based on the 330kV local power grid in Northwest China, this paper studies the power grid operation mode, DC component of short-circuit current and the influence of photovoltaic power station on short-circuit current. The influence law of DC component of short-circuit current on the actual breaking capacity of circuit breaker and access of photovoltaic power station on the short-circuit current are summarized. It can provide a theoretical basis for the selection of circuit breaker in novel power system.
Analysis of power quality problems in DC distribution network
Authors: Guan Shangshu , Song Yidan , Tao Shun
Published: May 2022

With the application and popularization of distributed power supply and power electronic equipment in power grid, AC distribution is faced with problems such as low efficiency and low power quality. At the same time, due to the advantages of large power supply capacity, long power supply radius, high efficiency, good controllability and adaptability to renewable energy access, DC power distribution has become a crucial development direction of the future distribution system. Reasonable and systematic analysis of power quality problems of DC distribution network plays an important role in its construction and application. Firstly, this paper introduces the background, significance and status of the research on DC distribution network and its power quality. Then introduces the three main topology of DC distribution network structure and connection mode. After selecting pseudo bipolar structure to build the simulation circuit, the power quality phenomena such as voltage sag are simulated and analyzed by PSCAD. The results obtained are consistent with theoretical analysis.
Resolution technology of lithography machine
Authors: Fang Yuanxuan , He Yunfei
Published: May 2022

Photolithography is one of the core methods in the semiconductor industry for the mass production of integrated circuits (IC). It is also the driving force behind Moore’s Law, which predicts the number of transistors in an integrated circuit to double every two years. This paper aims to overview the photolithography process and its current situations, starting with the rationale behind it and its advantages. We review the photolithography process in individual steps and gave typical process parameters when applicable. Then we introduce the major photolithography system manufacturers of interest, followed by an overview of techniques used to improve the resolution of photolithographic systems, namely immersion lithography, Extreme-Ultraviolet (EUV) lithography, and Resolution Enhancement Techniques (RETs). Finally we discuss the challenges encountered in lithography technology.
Authenticated encryption chip implementation against side-channel attack
Authors: Ma Xiaoyu , Zhang Fan , Han Yan
Published: May 2022

An authenticated encryption chip with novel nonce generation circuit was developed. This circuit associates the nonce generation with the contents and receiving time of plaintext. It will also generate overlapping power compensation for the whole chip. The integrated chip was fabricated under SMIC 180nm technology. Under 1.8V VDD, 100MHz global clock, the power consumption is about 14mW within 50k gates. The test result exhibits more than 10 times the strength in resistance to side-channel attack than the unprotected version without increasing hardware cost.
Research on intrusion detection method based on feature selection and integrated learning
Authors: Liu Qun , Tong Zhiyong , Wang Shuiqing , Yang Ziheng
Published: May 2022

With the introduction of computer technology, network attacks have become more frequent. Some illegal elements may intrude into computers through network attacks to tamper with messages, spread viruses and other destructive behaviors, causing great damage to personal sensitive information, industrial control networks, transaction systems, etc. . For this, this design proposes an improved intrusion detection method based on feature selection and integrated model. The NSL-KDD training data set is used to evaluate the proposed model. First, balance the data categories through the SMOTE-ENN method, and then use feature selection technology and PCA feature extraction technology to reduce the number of irrelevant features and improve the classification accuracy. Finally, using CART as the base classifier, Bagging technology is used to establish an integrated model and an intrusion detection system. Experimental results show that the CART-based Bagging method provides better accuracy, lower false alarm rate and faster model training speed, and the system can detect intrusion attacks with similar attributes and has a certain degree of adaptability.
SAR image simulation of sea surface targets
Authors: Cheng Xianping , Xia Weijie
Published: May 2022

SAR(Synthetic Aperture Radar) images of sea targets are of great significance to the military. In view of the high cost of obtaining the measured data of sea targets SAR images, this paper implements a sea target SAR image simulation method based on electromagnetic scattering calculations. This method uses the Phillips spectrum to generate the sea surface geometric model, and combines the target model and the sea surface model; then uses the SBR(Shooting and Bouncing Rays) to calculate the electromagnetic scattering of the sea surface target; finally, the SAR image of the sea surface target is simulated by the RCS(Radar Cross Section) obtained by the calculation. Through the analysis of the results of different sea states and different incident angles, it is shown that this method can complete the SAR image simulation of sea surface targets at different sea states and different angles, and the simulation effect is relatively realistic.