bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced performance of GdBCO bulk superconductors by doping a new kind of YGdBa4CuNbO
y
nanoparticles
Authors: Cui YanLan , Yang WanMin
Published: January 2024

In this work, a new kind of YGdBa4CuNbO
y
(YGdNb-11411) nano-particles was designed and sintered using a solid-state reaction method, whereas their impact on the performance of GdBCO bulks was investigated for the first time. From the acquired x-ray diffraction data and scanning electron microscopy imaging results, it was proved that the YGdNb-11411 particles were of excellent chemical stability and did not react with other phases during the crystal growth process. The YGdNb-11411 particles ranged from 80 to 130 nm and they were uniformly distributed in the well-textured GdBCO bulk superconductors. The maximum critical current density (J
c-max) of the samples was enhanced from 3.48 × 104 A cm−2 to 8.63 × 104 A cm−2 (77 K) in the self-field as the doping amount increased from 0 wt% to 7 wt%. In addition, the GdBCO sample with YGdNb-11411 particles also showed an enhanced flux pinning force density and relatively high J
c around the magnetic flux density range of 1 T–2 T (77 K). These results clearly indicated that the YGdNb-11411 particles could effectively enhance the properties of the GdBCO bulk superconductors.
Low-frequency electron–phonon interaction and superconductivity in
L12
-type trialuminides Al3V
Authors: Liu Feihu , Che Junling , Fu Wei , Wu Li-Na
Published: January 2024

Superconductivity enhancement is often associated with phonon softening by doping or external pressure. In this paper, we report

L

1
2

-type trialuminides Al3V as a typical example belonging to this scenario. The electronic, phononic and superconducting properties have been studied by using the first-principle method. Under uniaxial compression, the superconducting transition temperature Tc
of Al3V can be increased from ≈1.5 K to its maximum at ≈7.3 K when the lattice approaches the structural instability. A detailed investigation of Al3V reveals that the (V: d)-(Al: p) hybrid bands are strongly coupled to the phonon modes with lower frequency. The uniaxial compression induces a significant softening of the phonon mode with non-zero phonon line-width, and yet keeps the electron density of states near the Fermi level unchanged. This leads to a stronger electron–phonon coupling (EPC) and therefore a higher Tc
. On the contrary, the

L

1
2

structure is more stable against the hydrostatic pressure and the phonon energy actually grows up when the hydrostatic pressure is increased. As a result, EPC becomes weaker and Tc
can be reduced to

⩽

0.3 K under high hydrostatic pressure. Our results present an interesting example that superconductivity can enhanced by tuning the softened phonon via pressure or doping.
Unidirectional and bidirectional photon transport blockade in driven atomic lattices of parity-time antisymmetry
Authors: Liu Xiao , Wu Jin-Hui
Published: January 2024

We propose a scheme for realizing exact parity-time (

P
T

) antisymmetry of complex susceptibility in a wide range of probe detuning by considering a one-dimensional lattice of cold atoms driven into the simplest three-level Λ configuration. This is attained by modulating the intensity of a standing-wave coupling field with a proper phase shift to counteract the product of a single-photon detuning and a two-photon detuning. Such a dynamically controlled

P
T

-antisymmetric lattice supports the integration of a few nontrivial scattering behaviors including unidirectional light reflectionless, asymmetric perfect absorption, and directional signal quenching. These behaviors, depending in particular on atomic densities and lattice lengths, facilitate the on-demand realization of unidirectional or bidirectional photon transport blockade.
Bright and dark solitons in a photonic nonlinear quantum walk: lessons from the continuum
Authors: Anglés-Castillo Andreu , Pérez Armando , Roldán Eugenio
Published: January 2024

We propose a nonlinear quantum walk model inspired in a photonic implementation in which the polarization state of the light field plays the role of the coin-qubit. In particular, we take profit of the nonlinear polarization rotation occurring in optical media with Kerr nonlinearity, which allows to implement a nonlinear coin operator, one that depends on the state of the coin-qubit. We consider the space-time continuum limit of the evolution equation, which takes the form of a nonlinear Dirac equation. The analysis of this continuum limit allows us to gain some insight into the existence of different solitonic structures, such as bright and dark solitons. We illustrate several properties of these solitons with numerical calculations, including the effect on them of an additional phase simulating an external electric field.
An investigation of the simulation response of GEM-based detector for the fast neutrons by employment of GEANT4 & MCNP MC codes
Authors: Ahmad Farzana , Zubair M , Thanh-Mai Vu , Jamil M
Published: January 2024

The current work explores the potential ability to identify fast neutrons with one Gas Electron multiplier (GEM) detector connected to a polyethylene (PE) converter. Hence, a simulation was tested utilizing the GEANT4 Monte Carlo and MCNP simulation codes. The GEM detector functions by detecting the charged particles generated by an (n, p) reaction on a polyethylene. Fast neutrons in the ranging with energy levels of 1.0 MeV to to 25 MeV have the ability to travel towards the detector surface and evaluation was conducted from its response. For the 1 mm, 2 mm and 3 mm converter thickness, the sensitivity remains ∼ 9.8% and 13.4%, and 14.2% respectively via GEANT4 QGSP_BERT_HP physics lists. For the same converter thicknesses, sensitivity remains ∼ 9% and 12%, and 12.5% using the QGSP_BIC_HP physics list. Using the MCNP, with a 1 mm, 2 mm and 3 mm converter thickness, the sensitivity remains ∼ 12.8%, 13.3% and 13.6% via cell-flux tally method, while with the MCNP pulse- height technique with the same converter thicknesses, the sensitivity remains ∼ 10.6%, 12% and 13.3% respectively. The current findings reveals that GEM detector exhibits a clear and efficient response to inserted fast neutrons. Consequently, GEM based detectors have a potential to be a better candidate for fast neutron detection.
Optimal Photometry of Point Sources: Joint Source Flux and Background Determination on Array Detectors—from Theory to Practical Implementation
Authors: Vicuña Mario L. , Silva Jorge F. , Mendez Rene A. , Orchard Marcos E. , Espinosa Sebastian , Tregloan-Reed Jeremy
Published: January 2024

In this paper we study the joint determination of source and background flux for point sources as observed by digital array detectors. We explicitly compute the two-dimensional Cramér–Rao absolute lower bound (CRLB) as well as the performance bounds for high-dimensional implicit estimators from a generalized Taylor expansion. This later approach allows us to obtain computable prescriptions for the bias and variance of the joint estimators. We compare these prescriptions with empirical results from numerical simulations in the case of the weighted least squares estimator (introducing an improved version, denoted stochastic weighted least-squares) as well as with the maximum likelihood estimator, finding excellent agreement. We demonstrate that these estimators provide quasi-unbiased joint estimations of the flux and background, with a variance that approaches the CRLB very tightly and are, hence, optimal, unlike the case of sequential estimation used commonly in astronomical photometry which is sub-optimal. We compare our predictions with numerical simulations of realistic observations, as well as with observations of a bona fide non-variable stellar source observed with TESS, and compare it to the results from the sequential estimation of background and flux, confirming our theoretical expectations. Our practical estimators can be used as benchmarks for general photometric pipelines, or for applications that require maximum precision and accuracy in absolute photometry.
Global Alfvénic modes excitation in ohmic tokamak plasmas following magnetic reconnection events
Authors: Kryzhanovskyy A. , Bonfiglio D. , Cappello S. , Veranda M.
Published: January 2024

A possible triggering mechanism of Alfvén waves (AWs) in tokamak plasmas, based on localized perturbations induced by magnetic reconnection events, is discussed in the framework of nonlinear viscoresistive 3D magnetohydrodynamics (MHD) modeling. Numerical simulations are performed with the SpeCyl code (Cappello and Biskamp 1996 Nucl. Fusion 36 571) that solves the equations of the viscoresistive MHD model in cylindrical geometry. We investigate a ohmic tokamak configuration where the m = 1, n = 1 internal kink mode (m is the poloidal mode number and n is the toroidal mode number) undergoes a complete reconnection process. An in-depth investigation of the process shows a spatio-temporal correlation between the velocity perturbations associated with the reconnection and the excitation of the shear AW in the core region and the global Alfvén eigenmodes, both with dominant m = 1, n = 0 periodicity. In particular they are observed to emanate from the outflow cones of the reconnection layer associated with the internal kink. The excitation mechanism described in this paper could explain the observations of Alfvénic fluctuations in the absence of energetic ions in several tokamak experiments documented in the literature and could contribute to AWs excitation in general, even in the presence of fast particles. This result shares similarities with analogous study in reversed-field pinch (RFP) configuration (Kryzhanovskyy et al 2022 Nucl. Fusion 62 086019) where AWs were found to be excited by the RFP sawtoothing.
Design optimization method of heating and cooling full cycle storage air conditioning in integrated energy system
Authors: Biao Qiao , Li Jintang , Tan Zhukui , Wang Yang , Li Ji , Liang Shukui , Qin Yipeng
Published: January 2024

Heating and cooling storage air conditioning is an important part of the integrated energy system, which can play an important role in the flexible conversion of thermoelectric coupling systems. Because storage air conditioning involves the dynamic characteristics of power supply on the source side and cold and heat demand on the load side, system capacity allocation is a problem of technical and economic optimization. This paper breaks through the traditional design method based on the hourly load distribution law of typical design days and proposes a performance-oriented design method for the bidirectional full-cycle dimension storage air conditioning system based on the system’s annual operation performance, which can take into account the hourly dynamic load distribution law of every day in the full heating season and the full cooling season coupled with the bidirectional demand of cold and heat loads. A more scientific and reasonable capacity configuration scheme for the storage air conditioning system is obtained. The design is presented with a concrete case.
Numerical simulation of convective heat transfer in the discharging process of external ice-melting ice storage systems
Authors: Song Kaiwen , Liu Zedong
Published: January 2024

The external ice-melting ice storage system was widely used because of its advantages of reducing peak power consumption, reducing energy consumption and emissions, and fast ice melting speed. However, designing the external ice-melting ice storage system proved to be a challenge, and the structure and flow of the water distribution system needed to be fully considered. In particular, the problem of unstable outlet water temperature limited the practical application of the external melting ice storage system. Aiming at the problem of unstable outlet water temperature, a three-dimensional CFD phase change model was constructed in this paper. By comparing with the experimental data, the impact of varying water flow rates on the thermal and cooling properties of the was investigated. The results indicated that when the water flow rate was 226 ml/min for the system with an ice thickness of 74 mm, the outlet temperature of the ice storage tank was consistently below 5°C, the Nusselt number of ice and water remained constant, and the convective heat transfer effect was improved. The numerical simulation results provided guidance for the design and practical application of the water distribution system of the external melting ice storage system.
Influence of parameters in two-phase spray heat dissipation of electronic components
Authors: Fu Hao , Zheng Lei , Chen Hua , Cheng Wen-long
Published: January 2024

The two-phase spray cooling system has the characteristics of high cooling medium utilization, strong cooling capacity, and less space, which can meet the increasing heat dissipation demand of electronic components. This paper established a two-phase spray heat transfer system with electron-fluorinated liquid perfluoro-4-methyl-2-pentene (FCM-47) as the experimental liquid. The influence of spray distance, nozzle flow characteristic coefficient, and atomization pressure difference on the spray characteristic and the heat dissipation performance of spray cooling in the boiling zone were studied. The experiment shows that the critical state will occur in advance when the spray distance is reduced to a certain height (3 mm). An optimal spray distance of 8 mm corresponds to the lowest surface temperature and maximum CHF (critical heat flux). Increasing the nozzle flow characteristic coefficient and spray pressure difference can improve the heat exchange by increasing flow. However, increasing the nozzle flow characteristic coefficient can increase CHF but has little effect on the critical temperature, and increasing the spray pressure difference can increase both the critical temperature and CHF. This is related to their effect on atomization characteristics.
Experimental study on the flow and heat transfer characteristics of pin-fin manifold microchannel heat sink
Authors: Pan Yuhui , Chen Hua , Shen Yitao , Cheng Wenlong
Published: January 2024

A manifold microchannel radiator with a cylindrical pin-rib microchannel is designed and fabricated to enhance the heat dissipation capability of the manifold microchannel radiator, and its flow and heat dissipation capability are investigated by experiments. The fabrication and experiment of the manifold pin-rib microchannel radiators are introduced in detail. The heat dissipation capability of manifold pin-rib microchannel radiators at different flow rates is compared. The result shows that the manifold pin-rib microchannel radiator has excellent heat dissipation performance. When HFE7100 is used as the working medium, the average heated surface temperature of the manifold pin-rib microchannel radiator is about 100°C at the thermal flux density of 1000 W/cm2.
Research on configuration strategies for reducing low-voltage line losses through distributed photovoltaics
Authors: Guo Xirong
Published: January 2024

Photovoltaic power generation is currently one of the primary ways to harness solar energy in the world. In the face of the severe fossil fuel and environmental crises that the world is currently confronting, photovoltaic power generation has clear advantages from both the perspectives of resource sustainability and environmental friendliness. This paper explores the configuration strategy for addressing power losses in voltage elevation and distribution by studying methods of distributed photovoltaic power generation that focus on local generation, local grid connection, local conversion, and local utilization. Finally, the effectiveness of the configuration strategy is demonstrated through case analysis.
Heat transfer and flow characteristics of cuo-al2o3 hybrid nanofluids in slotted finned channels
Authors: Wu Shihao , Xu Genghao , Lin Haosen , Xiao Wensheng , Ma Lei
Published: January 2024

This study aimed to investigate the heat transfer coefficient of CuO-Al2O3 hybrid nanofluids within a microchannel heatsink, focusing on the impact of flow rate and volume fraction. The thermal conductivity and viscosity of hybrid nanofluids with different particle ratios were investigated. The results showed that the nanofluids have a more remarkable enhancement in thermal conductivity than water. Employing the hybrid nanofluids enhanced the heat transfer coefficient significantly. Furthermore, a slight growth in the friction factor was observed.
Integrated modeling method of the internal and external flow of helicopter/inlet
Authors: Su Zhimin , Cheng Benlin , Huang Xing , Cui Jiahang , Cai Feichao
Published: January 2024

The internal and external integrated flow field modeling method of the helicopter/inlet system was studied. The boundary of internal flow field modeling was proposed. The internal and external integrated calculation model, including the helicopter fuselage, rotor, tail rotor, and other rotating components, as well as the internal flow field of the inlet, was established. On this basis, numerical calculation is carried out according to typical working conditions to analyze the flow field characteristics in the forward flight state and the influence of inlet back pressure on performance parameters. The results show that the integrated numerical calculation model established in this paper considers the internal and external interference of the actual rotor movement in the outflow field. The integrated flow field calculation in typical working conditions shows that the occlusion of the rotor blade and the fuselage will cause interference with the inlet flow field. The parameters of the left and right inlet ports will be different. With the decrease of inlet back pressure, the total pressure recovery decreases with the increase of flow rate and is obviously lower than that without rotor interference.
Instability of viscous annular liquid film jet under high air-to-fluid velocity rate
Authors: Shi Haozhe
Published: January 2024

Based on the surface wave dispersion relation equation of viscous annular liquid film jet established by the research group in the early stage, a dispersion relation equation calculation program is written according to Mathematica. A linear stability analysis is carried out for the high air-fluid velocity ratio viscous annular liquid film jet entering a compressible gas medium environment. The relationship between the surface wave growth rate of an annular liquid film jet and the surface wave number under different characteristic parameters is obtained. The connection based on the dominant wave’s growth rate or the dominant wave’s number with dimensionless parameters such as air-fluid velocity rate, air-fluid density rate, Weber number of liquid, liquid Reynolds number, and gas Mach number was analyzed. The consequences reveal that under the high air-fluid velocity ratio, the increase of the above dimensionless parameters promotes the fragmentation course of the annular liquid film jet. Moreover, the augment of the air-fluid velocity rate has the greatest influence on the stability of the viscous annular liquid film jet. In contrast, the Reynolds number of the liquid has less influence than the reliability of the annular liquid film jet. Linear stability analysis under this condition lays the foundation for the prediction model of the most unstable parameters of annular liquid film jet in practical engineering applications.
Track reconstruction for the COMET Phase-II experiment with ACTS
Authors: Razquin Amaia , Lee MyeongJae
Published: January 2024

An implementation of A Common Tracking Software (ACTS) toolkit for signal electron
reconstruction for the COMET muon to electron conversion experiment is discussed. The
COMET experiment in J-PARC, Japan, will search for neutrinoless conversion of muons into electrons
in the field of an aluminium nucleus, a lepton flavour violating process, aiming target
sensitivity of 10-17. To achieve its scientific goals, the experiment requires a
reconstructed momentum resolution of lower than 150 keV/c. For the first time by applying ACTS to
signal events in the 100 MeV energy range with multiple-turn trajectories in the presence of
background events, it is found that the reconstruction efficiency is around 14% with no fake
reconstructed events. The implementation details, performance, and issues of ACTS in the context
of COMET are presented.
Electronic properties of ZrO2 films fabricated via atomic layer deposition on 4H-SiC and Si substrates
Authors: Wang Xi-Rui , Zeng Yu-Xuan , Zhang Jie , Huang Wei , Ma Hong-Ping , Zhang Qing-Chun
Published: January 2024

Being an important semiconductor material for high power applications, silicon carbide (SiC) faces the problems while used as a gate oxygen layer in traditional Si MOS devices. In view of this, an innovative approach was adopted in the present work to replace the conventional SiO2 with a high-k material (ZrO2) as the gate oxygen layer to investigate its effect on the electrical characteristics of the devices. In particular ZrO2 films were deposited on Si and SiC substrates by atomic layer deposition (ALD), and Al was used as the electrode. The atomic force microscopy (AFM) microregion scan revealed a highly flat surface with Rq < 1 nm after the ALD growth of ZrO2 layer. The sample surface analysis via x-ray photoelectron spectroscopy (XPS) suggested the presence of a small amount of ZrOx components. According to the electron energy loss spectrum (EELS), the band gap width (Eg) of this ALD ZrO2 dielectric was 5.45 eV, which met the requirements for high-quality 4H-SiC-related MOS devices. The electrical properties of the samples were then studied, and the maximum breakdown voltage of the Al/ZrO2/SiC/Al MOS structure was obtained to be 23 V, i.e., nearly twice that of the Si substrate. As for the oxide layer, the interface defect density (Dit) near the conduction band of the Al/ZrO2/SiC/Al MOS structure was only 1012 eV−1 cm−2 orders of magnitude. The Neff value (the movable charge) of the structure was also controlled at 1012 cm−2. Therefore, the overall performance of the ZrO2/SiC structure in terms of electrical properties exceeded that of the ZrO2/Si structure and previously reported counterparts. In this respect, the ZrO2/SiC MOS capacitor structure has great research potential.
Experimental study of the effect of the concentration of water/polyalkylene glycol solutions on heat transfer in steels subjected to quenching
Authors: Buenrostro Brandon Farrera , Bocanegra Constantin Alberto Hernández , Banderas José Angel Ramos , Valdovinos Luis Enrique Molina , Granados Nancy Margarita López , Vapalahti Sami
Published: January 2024

In this work, the heat transfer coefficients were determined utilizing an experimental study for cooling a 15B35H boron steel, using aqueous solutions of polyalkylene glycol (PAG) as a cooling fluid. A cooling tank was designed and built to allow the fluid recirculation, where the effect of agitation and the PAG content in a concentration range of 2%–6% vol. were analyzed. The thermal histories of cylindrical probes instrumented with K-type thermocouples were obtained, and the heat transfer coefficients associated with the types of refrigeration were calculated, solving the IHCP. The results show the presence of two maximum surface heat flux denominated q1max for the low-temperature range and q2max for the high-temperature range. Getting higher q1max and low q2max is desirable to avoid distortion and cracking. It was found that 4% PAG exhibits a slight variation of heat flux values in both low and high-temperature regions, regardless of the degree of agitation, maintaining values of about 3 MW·m−2 for q1max and 5.5 MW·m−2 for q2max. In this case, q2max is higher than q1max, leading to higher cooling rates in the martensitic transformation zone, increasing the risk of distortion and cracking. In the cases of 2 y 6% PAG, agitation affects q1max ranging from 2.5 to 6 MW·m−2, and for q2max from 4 to 6 MW·m−2, where q1max is always higher than q2max, providing better conditions for quenching.
A compatibility study of protective coatings for temperature sensor integration into sodium-ion battery cells
Authors: Vincent Timothy A , Maddar Faduma M , Chao Sheng , Guk Erdogan , Sansom Jonathan E H , Gulsoy Begum , Copley Mark , Hasa Ivana , Marco James
Published: January 2024

Instrumented battery cells (i.e. those containing sensors) and smart cells (with integrated control and communication circuitry) are essential for the development of the next-generation battery technologies, such as Sodium-ion Batteries (SIBs). The mapping and monitoring of parameters, for example the quantification of temperature gradients, helps improve cell designs and optimise management systems. Integrated sensors must be protected against the harsh cell electrolytic environment. State-of-the-art coatings include the use of Parylene polymer (our reference case).

We applied three new types of coatings (acrylic, polyurethane and epoxy based) to thermistor arrays mounted on flexible printed circuit board (PCBs). We systematically analyse the coatings: (i) PCB submersion within electrolyte vials (8 weeks); (ii) analysis of sample inserted into coin cell; (iii) analysis of sensor and cell performance data for 1Ah pouch SIBs. Sodium-based liquid electrolyte was selected, consisting of a 1 M solution of sodium hexafluorophosphate (NaPF6) dissolved in a mixture of ethylene carbonate and diethylene carbonate in a ratio of 3:7 (v/v%). Our novel experiments revealed that the epoxy based coated sensors offered reliable temperature measurements; superior performance observed compared to the Parylene sensors (erroneous results from one sample were reported, under 5 d submersed in electrolyte).

Nuclear magnetic resonance (NMR) spectroscopy revealed in the case of most coatings tested, formation of additional species occurred during exposure to the different coatings applied to the PCBs. The epoxy-based coating demonstrated resilience to the electrolytic-environment, as well as minimal effect on cell performance (capacity degradation compared to unmodified-reference, within 2% for the coin cell, and within 3.4% for pouch cell). The unique methodology detailed in this work allows sensor coatings to be trialled in a realistic and repeatable cell environment. This study demonstrated for the first time that this epoxy-based coating enables scalable, affordable, and resilient sensors to be integrated towards next-generation Smart SIBs.
Study on the mechanism of oxygen atom-related non-covalent interactions on the structure of non-fused ring acceptor molecules and their optoelectronic properties
Authors: Wang Miao , Wang Lei , Gao Huanhuan , Li Jin , Liu Zhao , Song Haiyang
Published: January 2024

Non-covalent interactions play a crucial role in regulating the molecular conformation and optoelectronic properties of the acceptor. In this paper, hydroxyl groups of different positions and numbers are inserted on the original non-fused ring acceptor molecule W0. Thus, eight novel molecules were designed. Density functional theory (DFT) and time-dependent DFT (TD-DFT) are used to investigate the mechanisms of non-covalent interactions between S…O on the molecular conformation, electronic structure and its optoelectronic properties. The existence of intramolecular S…O non-covalent interactions was demonstrated by the Atoms-In-Molecules topological analysis and RDG isosurface visualization. The study of the molecular conformational planarity revealed that the introduction of unilateral groups can optimize the homolateral planarity. As the number of hydroxyl insertions increases, the twisting of the two thiophene units within the central core intensifies. This also leads to an impact on the internal planarity of the central core. The electrostatic potential (ESP) analysis showed that the asymmetric hydroxyl modification increased the dipole moment and may be more beneficial for electron transfer. The larger the dipole moment, the more negative the ESP. Theoretical results show that the introduction of hydroxyl groups is significantly superior in terms of light absorption, dipole moment and exciton binding energy as well as excitation energy. As the number of hydroxyl groups increases, they show more potential in increasing the excitation energy and light absorption and decreasing the exciton binding energy. This study provides new insights into the design and development of high-performance non-fused ring acceptors.
Recent advances in fabrication and functions of neuromorphic system based on organic field effect transistor
Authors: Liu Yaqian , Lian Minrui , Chen Wei , Chen Huipeng
Published: January 2024

The development of various artificial electronics and machines would explosively increase the amount of information and data, which need to be processed via in-situ remediation. Bioinspired synapse devices can store and process signals in a parallel way, thus improving fault tolerance and decreasing the power consumption of artificial systems. The organic field effect transistor (OFET) is a promising component for bioinspired neuromorphic systems because it is suitable for large-scale integrated circuits and flexible devices. In this review, the organic semiconductor materials, structures and fabrication, and different artificial sensory perception systems functions based on neuromorphic OFET devices are summarized. Subsequently, a summary and challenges of neuromorphic OFET devices are provided. This review presents a detailed introduction to the recent progress of neuromorphic OFET devices from semiconductor materials to perception systems, which would serve as a reference for the development of neuromorphic systems in future bioinspired electronics.
All fiber single frequency pulsed Yb doped laser source scaling up to 600 uJ at 1 kHz
Authors: Yang Y J , Wu T F , Li C Y , Xia C Q , Li K T , Li Q S , Zhang Z Q , Han S
Published: January 2024

An all-fiber based high energy single frequency pulsed laser at 1030 nm with fixed repetition rate of 1 kHz was demonstrated. The system adopts a master oscillator power amplifier configuration. In the main amplification stage, we employed a highly doped, very large core diameter of 50 μm YDF fiber as the laser gain media. 670 μJ, 500 ns pulse train was obtained, corresponding to a peak power of 1.34 kW. Such a high-peak-power and high-repetition-rate SF source is well suited for long range coherent imaging, optical remote sensing, and coherent interferometry, etc.
Enhancing friction stir welding efficiency through rotational speed adjustment: a microstructural and mechanical analysis of Al-Cu alloy
Authors: Sasikala P , Madhusudhan R
Published: January 2024

Friction stir welding (FSW) has gained prominence in the aerospace and automotive industries due to its ability to produce high-strength and defect-free welds in aluminum alloys. The present investigation focuses on the impact of different tool rotational speeds (such as 700 rpm, 900 rpm, 1100 rpm and 1300 rpm), on the microstructure and mechanical characteristics of friction stir welded Al-Cu alloys. With the use of optical microscopy, scanning electron microscopy (SEM), x-ray diffraction (XRD), and evaluations of hardness, tensile characteristics, and fracture behavior, a thorough analysis was carried out. The weld nugget zone contained significant changes in grain size and shape as a function of rotational speed, as shown by microstructural analysis. The grain structure gradually became more refined when the rotating speed was raised from 900 to 1500 rpm. According to SEM observations, at faster speeds, the weld zone showed fewer defects per unit area and better bonding properties, which might be attributed to better material flow and plastic deformation. The effect was further clarified by XRD analysis, which showed differences in phase composition with varying rotating speeds. Evaluations of the mechanical properties showed a significant relationship between rotating speed and the mechanical performance of the welds. Hardness measurements showed that as rotating speed increased, hardness levels gradually increased. Welds made at faster rotational speeds had better elongation and tensile qualities, according to tensile tests. Additionally, fracture behavior study revealed that higher rotational speed welds displayed a more ductile fracture mode, indicating increased toughness.
Phase transitions in the mini-batch size for sparse and dense two-layer neural networks
Authors: Marino Raffaele , Ricci-Tersenghi Federico
Published: January 2024

The use of mini-batches of data in training artificial neural networks is nowadays very common. Despite its broad usage, theories explaining quantitatively how large or small the optimal mini-batch size should be are missing. This work presents a systematic attempt at understanding the role of the mini-batch size in training two-layer neural networks. Working in the teacher-student scenario, with a sparse teacher, and focusing on tasks of different complexity, we quantify the effects of changing the mini-batch size m. We find that often the generalization performances of the student strongly depend on m and may undergo sharp phase transitions at a critical value

m

c

, such that for

m
<

m

c

the training process fails, while for

m
>

m

c

the student learns perfectly or generalizes very well the teacher. Phase transitions are induced by collective phenomena firstly discovered in statistical mechanics and later observed in many fields of science. Observing a phase transition by varying the mini-batch size across different architectures raises several questions about the role of this hyperparameter in the neural network learning process.
Engineering zeolitic imidazolate framework-8 nanoparticles for smart drug delivery systems
Authors: Wu Cuixiu , Huang Wanyuan , Du Fengyi , Zhang Miaomiao , Qian Hanliang
Published: January 2024

Zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs) are emerging metal–organic framework nanomaterials composed of 2-methylimidazole and zinc ions, which are widely used in biomedical fields due to their distinctive features such as high porosity, bioresponsive degradation, and superior biocompatibility. Especially, the advanced research of ZIF-8 NPs in smart drug delivery systems is providing unique insights into the rational design of versatile nanomedicines for the treatment and diagnosis of serious diseases. This article provides a comprehensive review and outlook on ZIF-8 NPs-based smart drug delivery systems (SDDSs) including the synthesis methods, drug loading strategies, surface modification, and stimuli-responsive release. In particular, we focus on the advantages of ZIF-8 NPs-based drug loading strategies between the metal coordination-based active loading and the physical packaging-based passive loading. Finally, the opportunities and challenges of ZIF-8 NPs as smart drug delivery carriers are discussed.
Property G and the 4-genus
Authors: Ni Yi
Published: January 2024

We say a null-homologous knot

K
K

in a

3
3

-manifold

Y
Y

has Property G, if the Thurston norm and fiberedness of the complement of

K
K

is preserved under the zero surgery on

K
K

. In this paper, we will show that, if the smooth

4
4

-genus of

K
×
{
0
}

K\times \{0\}

(in a certain homology class) in

(
Y
×
[
0
,
1
]
)
#
N

C

P
2

¯

(Y\times [0,1])\#N\overline {\mathbb CP^2}

, where

Y
Y

is a rational homology sphere, is smaller than the Seifert genus of

K
K

, then

K
K

has Property G. When the smooth

4
4

-genus is

0
0

,

Y
Y

can be taken to be any closed, oriented

3
3

-manifold.
Dalston Children’s Centre
Authors: Brooke Stephen
Published: January 2024

The Dalston Children’s Centre was founded in the early 1980s to provide free and non-sexist, non-racist, non-heterosexist childcare to parents in Hackney. This chapter explores the history of the Dalston Children’s Centre as an example of alternative culture in 1980s London. In particular, it considers the Centre as an experiment in feminism, lesbian rights, and anti-racism. There are connections here with the struggles of Gay’s the Word bookshop and feminism in the 1980s. The chapter also reflects upon the tensions within radical or alternative politics in the 1980s.
The Anti-Apartheid March
Authors: Brooke Stephen
Published: January 2024

In June 1984, Margaret Thatcher hosted P. W. Botha, the Prime Minister of apartheid South Africa, on a state visit to London. The visit provoked intense opposition from the anti-apartheid movement in London, and a major demonstration was held to protest against the visit. This chapter examines that march as an illustration of London’s place as a locus of global radicalism, in this case the anti-apartheid movement. As the chapter shows, London had long been a centre of anti-apartheid activism. In the 1980s, that profile was heightened, in part by the growing visibility and strength of a global anti-apartheid movement, and in part by the support lent to the anti-apartheid cause by the GLC. The chapter argues that questions of race and anti-racism in the 1980s could only be discussed as a connection between the local and the global.
An Intersectoral Approach to Hypertension Care: Solutions for Improving Blood Pressure Control in São Paulo, Brazil
Authors: Avezum Álvaro , Drager Luciano F , Reiker Theresa , Bigoni Alessandro , Leonel Lays P , Abreu Ariane , Bortolotto Luiz , Palmeirim Marta Sólveig , Silveira Mariana , Aquino Beatriz , Maggion Rafael Venijio , Baxter Yara Carnevalli , Cobos Muñoz Daniel , Dib Karina Mauro , Amaral Amaury Zatorre , Saric Jasmina , Jarrett Caitlin , Boch Johannes
Published: January 2024

BACKGROUND

Hypertension is the leading risk factor for cardiovascular diseases (CVDs) and a major public health issue worldwide. In Brazil, it affects approximately 52.5% of the adult population. We describe the solutions package and the impact of a population health initiative in São Paulo city, following the CARDIO4Cities approach for the management of cardiovascular risk.

METHODS

Using a design thinking approach, interventions were developed with a coalition of local and international stakeholders to address needs of patients, healthcare professionals, and the health system. The resulting solution package was checked to comply with guidelines for non-communicable disease and hypertension management. Clinical impact was measured by extracting the hypertension cascade of care—monitored, diagnosis, treatment, and control—from medical records.

RESULTS

Under the leadership of the municipal health authorities, nine solutions were piloted and scaled across the city. Solutions conform with local and international best-practices. Between October 2017 and December 2021, 11,406 patient records were analyzed. Results showed a 40% increase in monitored patients (patients with at least one blood pressure, BP, measurement); reduced proportions of patients diagnosed among those with available BP measurements (72%–53%) and treated among diagnosed (93%–85%); and an improvement in controlled patients among those receiving treatment (16%–27%).

CONCLUSIONS

The solution package described in this study was correlated with increased BP control. The implementation methodology and results add to the body of real-world evidence supporting population health implementation science in Brazil and beyond.
The Pathogenesis and Impact of Arterial Stiffening in Hypertension: The 2023 John H. Laragh Research Award
Authors: Liu Jing , Wu Jing
Published: January 2024

Fifty years ago, Dr. John Laragh brought forward the “vasoconstriction-volume hypothesis” of hypertension. This is Ohm’s Law in blood pressure regulation, explicating hypertension as a consequence of increased peripheral vascular resistance, cardiac output, or both. Resistance vessels, those of a diameter less than 200 μm, determines mean arterial pressure by controlling peripheral vascular resistance. In comparison, large capacitance arteries, particularly the aorta, confines the systolic and diastolic blood pressure in physiological range through the “windkessel effect.” Loss of this cushioning function results in aortic stiffening and isolated systolic hypertension, both of which are independently associated with increased risk for coronary, cerebral, and renal diseases. Aortic stiffening is both a cause and a consequence of hypertension. On one hand, aortic stiffness precedes the onset of hypertension in populations and experimental models, and hemodynamic derangements related to aortic stiffening contributes to the development of hypertension by promoting renal dysfunction. On the other hand, the vasculature itself is a hypertensive target organ and hypertensive mechanical stretch directly induces the pathogenesis of aortic adventitial remodeling. Various cell types, including bone marrow-derived circulating fibrocytes, vascular stem cell antigen-1 positive progenitors, and endothelial to mesenchymal transition, and to a lesser extent resident fibroblasts, contribute to adventitial matrix deposition and aortic stiffening in hypertension. Vascular smooth muscle stiffness is another important contributor of aortic stiffening. Understanding the roles of immune components and specific signal pathways in the pathogenesis aortic stiffening paves the path to novel antihypertensive and anti-fibrosis therapies.
Hypertension and Mild Cognitive Impairment: State-of-the-Art Review
Authors: Shajahan Sultana , Peters Ruth , Carcel Cheryl , Woodward Mark , Harris Katie , Anderson Craig S
Published: January 2024

BACKGROUND

Mid-life hypertension is associated with cognitive decline and dementia in later life. Reducing high blood pressure (BP) with antihypertensive agents is a well-researched strategy to prevent dementia and mild cognitive impairment (MCI). However, there is still limited direct evidence to support the approach, and particularly for the treatment of the very old and those with existing MCI.

METHODS

This review presents an overview of the current evidence for the relationship between MCI and hypertension, and of the potential pathophysiological mechanisms related to cognitive decline and incidence dementia in relation to aging.

RESULTS

Although observational data are near consistent in showing an association between mid-life hypertension and MCI and/or dementia, the evidence in relation to hypertension in younger adults and the very old (age >80 years) is much more limited. Most of the commonly available antihypertensive agents appear to provide beneficial effects in reducing the risk dementia, but there is limited evidence to support such treatment in those with existing MCI.

CONCLUSIONS

Further studies are needed to determine the optimal levels of BP control across different age groups, especially in adults with MCI, and which class(es) of antihypertensive agents and duration of treatment best preserve cognitive function in those at risk of, or with established, MCI.
Seq-InSite: sequence supersedes structure for protein interaction site prediction
Authors: Hosseini SeyedMohsen , Golding G Brian , Ilie Lucian
Published: January 2024

Motivation

Proteins accomplish cellular functions by interacting with each other, which makes the prediction of interaction sites a fundamental problem. As experimental methods are expensive and time consuming, computational prediction of the interaction sites has been studied extensively. Structure-based programs are the most accurate, while the sequence-based ones are much more widely applicable, as the sequences available outnumber the structures by two orders of magnitude. Ideally, we would like a tool that has the quality of the former and the applicability of the latter.

Results

We provide here the first solution that achieves these two goals. Our new sequence-based program, Seq-InSite, greatly surpasses the performance of sequence-based models, matching the quality of state-of-the-art structure-based predictors, thus effectively superseding the need for models requiring structure. The predictive power of Seq-InSite is illustrated using an analysis of evolutionary conservation for four protein sequences.

Availability and implementation

Seq-InSite is freely available as a web server at http://seq-insite.csd.uwo.ca/ and as free source code, including trained models and all datasets used for training and testing, at https://github.com/lucian-ilie/Seq-InSite.
methyLImp2: faster missing value estimation for DNA methylation data
Authors: Plaksienko Anna , Di Lena Pietro , Nardini Christine , Angelini Claudia
Published: January 2024

Motivation

methyLImp, a method we recently introduced for the missing value estimation of DNA methylation data, has demonstrated competitive performance in data imputation compared to the existing, general-purpose, approaches. However, imputation running time was considerably long and unfeasible in case of large datasets with numerous missing values.

Results

methyLImp2 made possible computations that were previously unfeasible. We achieved this by introducing two important modifications that have significantly reduced the original running time without sacrificing prediction performance. First, we implemented a chromosome-wise parallel version of methyLImp. This parallelization reduced the runtime by several 10-fold in our experiments. Then, to handle large datasets, we also introduced a mini-batch approach that uses only a subset of the samples for the imputation. Thus, it further reduces the running time from days to hours or even minutes in large datasets.

Availability and implementation

The R package methyLImp2 is under review for Bioconductor. It is currently freely available on Github https://github.com/annaplaksienko/methyLImp2.
Microbial interactions from a new perspective: reinforcement learning reveals new insights into microbiome evolution
Authors: Ghadermazi Parsa , Chan Siu Hung Joshua
Published: January 2024

Motivation

Microbes are essential part of all ecosystems, influencing material flow and shaping their surroundings. Metabolic modeling has been a useful tool and provided tremendous insights into microbial community metabolism. However, current methods based on flux balance analysis (FBA) usually fail to predict metabolic and regulatory strategies that lead to long-term survival and stability especially in heterogenous communities.

Results

Here, we introduce a novel reinforcement learning algorithm, Self-Playing Microbes in Dynamic FBA, which treats microbial metabolism as a decision-making process, allowing individual microbial agents to evolve by learning and adapting metabolic strategies for enhanced long-term fitness. This algorithm predicts what microbial flux regulation policies will stabilize in the dynamic ecosystem of interest in the presence of other microbes with minimal reliance on predefined strategies. Throughout this article, we present several scenarios wherein our algorithm outperforms existing methods in reproducing outcomes, and we explore the biological significance of these predictions.

Availability and implementation

The source code for this article is available at: https://github.com/chan-csu/SPAM-DFBA.