Research on the Voltage Supporting Capability of Multi-VSC-HVDC Subsystems Operation Strategy to Receiving-end LCC-HVDC Network in Weak AC Grid

For the hybrid multi-infeed HVDC system in which the receiving-end grid is a strong AC grid including LCC-HVDC subsystems and multiple VSC-HVDC subsystems,it has higher voltage support capability.However,for weak AC grid,the voltage support capability of the multi-VSC-HVDC subsystems to the LCC-HVDC subsystem(voltage support capability-mVSCs-LCC)can resist the risk of commutation failure.Based on this consideration,this paper proposes an evaluation index called Dynamic Voltage Support Strength Factor(DVSF)for the hybrid multi-infeed system,and uses this index to qualitatively judge the voltage support capability-mVSCs-LCC in weak AC grid.In addition,the proposed evaluation index can also indirectly judge the ability of the LCC-HVDC subsystem to suppress commutation failure.Firstly,the mathematical model of the power flow of the LCC and VSC networks in the steady-state is analyzed,and the concept of DVSF applied to hybrid multi-infeed system is proposed.Furthermore,the DVSF index is also used to qualitatively judge the voltage support capability-mVSCs-LCC.Secondly,the influence of multiple VSC-HVDC subsystems with different operation strategies on the DVSF is analyzed with reference to the concept of DVSF.Finally,the indicators proposed in this paper are compared with other evaluation indicators through MATLAB simulation software to verify its effectiveness.More importantly,the effects of multi-VSC-HVDC subsystems using different coordinated control strategies on the voltage support capability of the receiving-end LCC-HVDC subsystem are also verified.

Partial Least Squares(PLS)Methods for Abnormal Detection of Breast Cells

Breast cancer is one of the malignant tumors having high incidence in women,the incidence of breast cancer has increased in all parts of the world since twentieth century,but its etiology is not yet completely clear,so it is very important to detect breast cells.In this paper,we built a regression model to detect breast cells,and generated a method for predicting the formation of benign and malignant breast cells by training the model,then we used the 10 features of breast cells to predict it,the results reaching upto 93.67%accuracy,it was very effective to predict and analyse whether the breast cells getting cancer,It had an important role in the diagnosis and prevention of breast cancer.

糖尿病呼出气体检测与分析研究进展

近年来,呼出气检测在糖尿病领域的研究引起了广泛关注。糖尿病作为一种代谢性疾病,利用现代检测分析方法,如气相色谱、质谱、光谱和传感器检测等,实现了对糖尿病患者呼出气体的检测和监测。本综述概述了糖尿病患者呼出气体中一些挥发性有机化合物的成分及其来源,并评估了以机器学习为基础的算法在支持糖尿病及其并发症风险预测模型方面的应用。此外,对国内外糖尿病呼出气检测的发展与应用进行了探讨,并对其局限性和未来潜在应用进行了评价。

Optimal replication strategy for mitigating burst traffic in information-centric satellite networks: a focus on remote sensing image transmission

Information-centric satellite networks play a crucial role in remote sensing applications,particularly in the transmission of remote sensing images.However,the occurrence of burst traffic poses significant challenges in meeting the increased bandwidth demands.Traditional content delivery networks are ill-equipped to handle such bursts due to their pre-deployed content.In this paper,we propose an optimal replication strategy for mitigating burst traffic in information-centric satellite networks,specifically focusing on the transmission of remote sensing images.Our strategy involves selecting the most optimal replication delivery satellite node when multiple users subscribe to the same remote sensing content within a short time,effectively reducing network transmission data and preventing throughput degradation caused by burst traffic expansion.We formulate the content delivery process as a multi-objective optimization problem and apply Markov decision processes to determine the optimal value for burst traffic reduction.To address these challenges,we leverage federated reinforcement learning techniques.Additionally,we use bloom filters with subdivision and data identification methods to enable rapid retrieval and encoding of remote sensing images.Through software-based simulations using a low Earth orbit satellite constellation,we validate the effectiveness of our proposed strategy,achieving a significant 17%reduction in the average delivery delay.This paper offers valuable insights into efficient content delivery in satellite networks,specifically targeting the transmission of remote sensing images,and presents a promising approach to mitigate burst traffic challenges in information-centric environments.

Lateral strain tailoring in manganite homostructures assisted by atomic-flat freestanding membranes

Complex oxide thin films exhibit intriguing phenomena due to the coupling between multiple degrees of freedom through interfacial structural engineering.Atomic tailoring of structural parameters determines unique band structure and phonon modes,regulating emergent magnetic and electrical properties of oxide films.However,the construction of different strained and oriented domains in one intact oxide thin film is impossible using conventional means.Here we report the fabrication and quantitative structural analysis of La_(0.7)Sr_(0.3)MnO_(3)(LSMO)homostructures assisted by atomic-flat freestanding membranes.Pristine substrates and suspended membranes regulate the epitaxial strain and orientation of subsequently grown films.Our results demonstrate an ultrathin transition layer(~4 atomic layers)between freestanding membranes and LSMO films is formed due to the strain relaxation.This work offers a simple and scalable methodology for fabricating unprecedented innovative functional oxide homostructures through artificially controlled synthesis routes.

Direct observation of epitaxial alignment of Au on M0S2 at atomic resolution

The morphology and structural stability of metal/2D semic on ductor interfaces strongly affect the performa nee of 2D electronic devices and synergistic catalysis. However, the structural evolution at the interfaces has not been well explored particularly at atomic resolution. In this work, we study the structural evoluti on of Au nan oparticles (NPs) on few-layer MoS2 by high resol utio n transmissi on electro n microscopy (HRTEM) an d quan titative high-angle annular dark field seanning TEM. It is found that in the transition of Au from nan oparticles to den drites, a dynamically epitaxial align ment betwee n Au and MoS2 lattices is formed, and Moirc patter ns can be directly observed in HRTEM images due to the mismatch between Au and M0S2 lattices. This epitaxial alignment can occur in ambient conditions, and can also be accelerated by the irradiation of high-energy electron beam. In situ observation clearly reveals the rotation of Au NPs, the atom migration inside Au NPs, and the transfer of Au atoms between neighboring Au NPs, finally leading to the formation of epitaxially aligned Au dendrites on M0S2. The structural evoluti on of metal/2D semico nductor in terfaces at atomic scale can provide valuable information for the design and fabricatio n of the metal/2D semicon ductorn ano-devices with desired physical and chemical performa nces.

Gas-discharge induced flash sintering of YSZ ceramics at room temperature

This is the first study to conduct the flash sintering of 3 mol%yttria-stabilized zirconia(3YSZ)ceramics at room temperature(25℃)under a strong electric field,larger than 1 kV/cm.At the standard atmospheric pressure(101 kPa),the probability of successful sintering is approximately half of that at low atmospheric pressure,lower than 80 kPa.The success of the proposed flash sintering process was determined based on the high electric arc performance at different atmospheric pressures ranging from 20 to 100 kPa.The 3YSZ samples achieved a maximum relative density of 99.5%with a grain size of~200 nm.The results showed that as the atmospheric pressure decreases,the onset electric field of flash sintering decreases,corresponding to the empirical formula of the flashover voltage.Moreover,flash sintering was found to be triggered by the surface flashover of ceramic samples,and the electric arc on the sample surfaces floated upward before complete flash sintering at overly high pressures,resulting in the failure of flash sintering.This study reveals a new method for the facile preparation of flash-sintered ceramics at room temperature,which will promote the application of flash sintering in the ceramic industry.

Review of flash sintering with strong electric field

Flash sintering is a novel field‐assisted sintering technology for ceramics that allows a dramatic reduction in processing time and temperature.Since 2010,when flash sintering was first reported,it has been a focus of research interest in the field of materials science.Recent study results have confirmed that the sintering temperature decreases with the strength of the applied electric field;for some ceramics,the sintering temperature can be lowered even to room temperature.This represents an innovative breakthrough for ceramic sintering at ultra‐low temperatures.However,once the electric field strength in flash sintering is increased,new questions and challenges arise,such as whether or not partial discharge occurs in the green body if under electro‐thermal coupling stress,how to quantitatively analyse the impact of discharge on sintering,and,moreover,whether the sintering mechanism under a strong electric field is consistent with that under a weak electric field.These research questions require knowledge of partial discharge detection,dielectric theory,and other topics that are beyond the scope of materials science.To address this need,this review summarises the work carried out in flash sintering with a strong electric field from the perspective of high voltage and insulation technology.First,the flash sintering process and mechanism are briefly introduced.Then,the published literature on flash sintering with a strong electric field for various ceramic materials is summarised in depth.In addition,experimental phenomena that are observed in flash sintering with a strong electric field,such as flash and blackening,are discussed.Finally,some suggestions for future work are presented.It is anticipated that the knowledge gap between different areas of study can be filled by this review.

Interface structure and strain controlled Pt nanocrystals grown at side facet of MoS_(2)with critical size

The heterostructure of transition metal nanocrystal on two-dimensional(2D)materials exhibits unique physical and chemical properties through various interfacial interactions.It has been established that the atomic structure and strain in the vicinity of the interface determine the band structure and phonon modes of the nanocrystal,regulating the optical and electrical properties of such heterostructures.Hence,metal–support interfacial engineering is a demonstrated approach to acquiring desired properties of the nanocrystals.However,a fundamental understanding of the interfacial structures remains elusive and precise control of the interactions has yet achieved.Herein,we explore the regulation of interface on MoS_(2)supported Pt nanocrystals which were prepared by reducing ultrasonic dispersed potassium chloroplatinate.The Pt-MoS_(2)heterostructure interface was systematically studied by aberration corrected transmission electron microscopy.Three types of Pt-MoS_(2)interfaces with distinct atomic configurations were identified.The strain within the Pt nanocrystals is sensitive to the atomic configuration of the supporting MoS_(2),which regulates the size of the Pt nanocrystals.These results provide insights on tuning of nanocrystal strain,paving the way for precise control of 2D semiconductor heterostructures.

Erratum to:Interface structure and strain controlled Pt nanocrystals grown at side facet of MoS_(2)with critical size

Erratum to Nano Research 2022,15(9):8493–8501 https://doi.org/10.1007/s12274-022-4449-5 The name of the first author in original paper was unfortunately misspelled.It should be“Yuchen Zhu”,instead of“Yucheng Zhu”.