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Near-field wideband beam training for ELAA with uniform circular array

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Science China(Information Sciences) 2024年第6期67卷 370-383页

作者： Yuhao CHEN Linglong DAI department of Electronic {1. Tsinghua UniversityBeijing National Research Center for Information Science and Technology (BNRist)

Extremely large-scale antenna array(ELAA) at millimeter wave(mmWave) and Terahertz(THz)band has been considered a key technology for combating high attenuation in high-frequency bands in future6G communications. Uniform circular arrays(UCAs) have attracted much attention because of their ability to provide flat beamforming gain at all angles. To realize efficient beamforming, beam training is widely used to acquire channel state information. However, with a large antenna number, the beam training overhead in ELAA systems becomes overwhelming. Moreover, with a large bandwidth, the beam defocus effect severely degrades beam training accuracy. To address these issues, this paper proposes a frequency-dependent focusing(FDF)-based beam training scheme to realize effective beam training in near-field wideband ELAA systems with UCA. Specifically, we first analyze the FDF property of UCA, where signals at different subcarriers can simultaneously focus on different distances. Then, by exploiting the FDF property to search different distances using different subcarriers simultaneously, we design a hierarchical codebook and propose an FDFbased beam training scheme. To reveal the effectiveness of the proposed scheme, we compare its necessary beam training overhead with that of existing schemes. Finally, the simulation results demonstrate that the proposed scheme can achieve accurate beam training in near-field wideband UCA systems with a low beam training overhead.

关键词： extremely large-scale antenna array (ELAA) uniform circular array (UCA) near-field wideband beam training

pH Induced Self-assembly of AIE Fluorescent Probe for Tumor Imaging

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Chinese Journal of Polymer Science 2024年第1期42卷 7-13,I0005页

作者： Jing-Yuan Xiang Wen-Long Zhang He-Ting Li Ya-Ning He department of Chemical {1. Key Laboratory of Advanced Materials(MOE)Tsinghua UniversityBejing 100084China

This work reported an AIE fluorescent probe for tumor imaging based on the p H induced self-assembly strategy. The fluorescent probe was composed of an acid-responsive soluble copolymer PEG-b-PAMA-DMMA with a maleic acid amide group and an anionic soluble aggregation-induced emission fluorogen(AIEgen) TPE-2SO_(3)^(-). The polymer could be transformed into a protonated amine-containing polymer after the hydrolysis of maleic acid amide in acidic tumor microenvironment, which would be further self-assembled with TPE-2SO_(3)^(-)to form aggregated nanoparticles. The transition of TPE-2SO_(3)^(-)from dispersed state to aggregated state led to an obvious increase in fluorescence intensity due to its AIE characteristics.

关键词： p H-responsive Self-assembly Fluorescent probe AIE Tumor imaging

Electrochemical reduction of carbon dioxide to produce formic acid coupled with oxidative conversion of biomass

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Journal of Energy Chemistry 2024年第5期92卷 705-729页

作者： Xi Liu Yifan Wang Zhiwei Dai Daihong Gao Xuebing Zhao Key Laboratory of Industrial Biocatalysis Ministry of EducationTsinghua UniversityBeijing 100084China Institute of Applied Chemistry Department of Chemical EngineeringTsinghua UniversityBeijing 100084China

Electrochemical reduction of CO_(2)(CO_(2)RR)has become a research hot spot in recent years in the context of carbon *** is one of the most promising products obtained by electrochemical reduction of CO_(2) due to its high energy value as estimated by market price per energy unit and wide application in chemical *** is the most abundant renewable resource in the natural *** biomass oxidative conversion with CO_(2)RR driven by renewable electricity would well achieve carbon *** this work,we comprehensively reviewed the current research progress on CO_(2)RR to produce HCOOH and coupled system for conversion of biomass and its derivatives to produce value-added ***-and Bi-based electrocatalysts are discussed for CO_(2)RR with regards to the structure of the catalyst and reaction ***-oxidation reactions of biomass derived sugars,alcohols,furan aldehydes and even polymeric components of lignocellulose were reviewed as alternatives to replace oxygen evolution reaction(OER)in the conventional electrolysis *** was recommended that to further improve the efficiency of the coupled system,future work should be focused on the development of more efficient and stable catalysts,careful design of the electrolytic cells for improving the mass transfer and development of environment-friendly processes for recovering the formed formate and biomass oxidation products.

关键词： Electrochemical reduction of CO_(2) Formic acid Oxidative conversion of biomass Lignocellulose Coupled system

Market Equilibrium Based on Cloud-edge Collaboration

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 96-104页

作者： Tong Cheng Haiwang Zhong Qing Xia the State Key Laboratory of Power Systems the Department of Electrical EngineeringTsinghua UniversityBeijing 100084China

Market participants can only bid with lagged information disclosure under the existing market mechanism,which can lead to information asymmetry and irrational market behavior,thus influencing market *** promote rational bidding behavior of market participants and improve market efficiency,a novel electricity market mechanism based on cloudedge collaboration is proposed in this *** market information,called residual demand curve,is published to market participants in real-time on the cloud side,while participants on the edge side are allowed to adjust their bids according to the information disclosure prior to closure *** proposed mechanism can encourage rational bids in an incentive-compatible way through the process of dynamic equilibrium while protecting participants’*** paper further formulates the mathematical model of market equilibrium to simulate the process of each market participant’s strategic bidding behavior towards equilibrium.A case study based on the IEEE 30-bus system shows the proposed market mechanism can effectively guide bidding behavior of market participants,while condensing exchanged information and protecting privacy of participants.

关键词： Cloud-edge collaboration market mechanism residual demand curve strategic bidding

Unlocking the potential of transdermal drug delivery

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International Journal of Smart and Nano Materials 2024年第3期15卷 432-468页

作者： Shuang Li Jianhao Wu Xiangjun Peng Xi-Qiao Feng Institute of Biomechanics and Medical engineering Applied Mechanics LaboratoryDepartment of Engineering MechanicsTsinghua UniversityBeijingChina

Transdermal drug delivery(TDD)has gained clinical approval over several decades,with extensive research dedicated to novel drug and device *** notable research progress,the mar-ket adoption of TDD devices has not met anticipated levels,with oral administration and injection remaining predominant delivery *** maximize the potential of TDD,we identify bottlenecks hinder-ing its widespread clinical application and propose promising research *** begin by analyzing stringent demands necessary to truly benefit patients,addressing significant challenges in biomechanics,nanomedicine,and flexible ***,we delve into skin anatomy,enhancement strategies,nano-carriers,and their under-lining mechanisms,highlighting the importance and framework of quantitative *** on these discussions,we highlight the core strength of TDD,such as automatic precise administration based on feedback and high delivery efficiencies,especially applicable to localized conditions(e.g.,central nervous system diseases,tumors).Finally,we envision the future of intelligent TDD device and its opera-tion scenario,aiming to steer research efforts toward faster translation of laboratory innovations into widely used products for sufferers.

关键词： Transdermal drug delivery biomechanics nanomedicine flexible electronics

An Automatic Implementation of Oropharyngeal Swab Sampling for Diagnosing Respiratory Infectious Diseases via Soft Robotic End-Effectors

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Chinese Journal of Mechanical engineering 2024年第2期37卷 55-67页

作者： Yafeng Cui Wenjie Yu Jingjing Li Qi Shao Ding Weng Guoping Yin Xiaohao Zhang Xinjun Liu Jingying Ye Jiadao Wang Huichan Zhao department of Mechanical {1. Tsinghua UniversityBeijing 100084China Beijing Huakang Tongbang Technology Company Beijing 102609China department of Otorhinolaryngology Beijing Tsinghua Changgung HospitalSchool of Clinical MedicineTsinghua UniversityBeijing 102218China Tianjin Research Institute for Advanced Equipment Tsinghua UniversityTianjin 300300China

The most widely adopted method for diagnosing respiratory infectious diseases is to conduct polymerase chain reaction(PCR)assays on patients’respiratory specimens,which are collected through either nasal or oropharyngeal *** manual swab sampling process poses a high risk to the examiner and may cause false-negative results owing to improper *** this paper,we propose a pneumatically actuated soft end-effector specifically designed to achieve all of the tasks involved in swab *** soft end-effector utilizes circumferential instability to ensure grasping stability,and exhibits several key properties,including high load-to-weight ratio,error tolerance,and variable swab-tip stiffness,leading to successful automatic robotic oropharyngeal swab sampling,from loosening and tightening the transport medium tube cap,holding the swab,and conducting sampling,to snapping off the swab tail and sterilizing *** an industrial collaborative robotic arm,we integrated the soft end-effector,force sensor,camera,lights,and remote-control stick,and developed a robotic oropharyngeal swab sampling *** this swab sampling system,we conducted oropharyngeal swab-sampling tests on 20 *** Digital PCR assay results(RNase P RNA gene absolute copy numbers for the samples)revealed that our system successfully collected sufficient numbers of cells from the pharyngeal wall for respiratory disease *** summary,we have developed a pharyngeal swab-sampling system based on an“enveloping”soft actuator,studied the sampling process,and imple-mented whole-process robotic oropharyngeal swab-sampling.

关键词： Diagnosis Medical robot Soft end-effector Swab-sampling Digital PCR

Voidage correction method for DEM study of 3D pebble flows in a bed of cycloidal base

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Particuology 2024年第10期93卷 30-40页

作者： Zirui Xia Minglei Shi Quan Zou Nan Gui Xingtuan Yang Jiyuan Tu Shengyao Jiang Institute of Nuclear and New Energy Technology Collaborative Innovation Center of Advanced Nuclear Energy TechnologyKey Laboratory of Advanced Reactor Engineering and SafetyMinistry of EducationTsinghua UniversityBeijing100084China department of {1. Physics Tsinghua UniversityBeijing100084China department of Automation Tsinghua UniversityBeijing100084China School of engineering RMIT UniversityMelbourneVIC3083Australia

Voidage(porosity or void fraction)in packed particles(or pebbles)is of fundamental importance in calculating the pressure drop,obtaining the drag,predicting the bed permeability,estimating the neutron streaming,*** the case when particles are deformed,a method of voidage correction during the packing state is proposed using a Discrete Element Method(DEM)simulation of 3D pebble flow inside a bed of cycloidal base.A function to evaluate the remaining volume of a pebble intercepted by horizontal and vertical planes is proposed for voidage *** that,the process of solving voidage distribution is provided in *** this method,the voidage inside the cycloidal-base pebble bed is obtained to refer to reported similar data for *** method can be potentially used for dynamical voidage calculation in CFD-DEM simulation which can get suitable voidage distribution after the correction.

关键词： Voidage Pebbleflow Packed bed Discreteelementmethod Cycloidal base KD-Tree Volume correction

Normalized glandular dose coefficients for digital breast tomosynthesis using detailed Chinese breast models

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Nuclear Science and Techniques 2024年第5期35卷 42-59页

作者： Jia-Hao Wang Rui Qiu An-Kang Hu Ye-Qi Liu Zhen Wu Hui Zhang Jun-Li Li department of {1. Physics Tsinghua UniversityBeijing 100084China Key Laboratory of Particle and Radiation Imaging Ministry of EducationTsinghua UniversityBeijing 100084China Joint Institute of tsinghua {1. Nuctech Company Limited BeijingBeijing 100084China

The rise in breast cancer diagnoses among Chinese women has necessitated the use of X-ray breast screening,which carries a radiation *** study aimed to provide a dosimetry protocol for the Chinese female population to replace the traditional standard that utilizes simplified breast models,for the accurate estimation of the mean glandular dose of a patient undergoing digital breast tomosynthesis(DBT).The first set of detailed Chinese female breast models and representative breast parameters was *** backscatter radiation and computational efficiency,we improved the combination of these models and the Chinese reference adult female whole-body voxel *** acquisition for four commercial DBT systems that are widely employed in China was simulated using the Monte Carlo method to obtain the normalized glandular dose coefficients of DBT(D_(gN)^(DBT))and the glandular depth dose(D_(g)^(dep)(z))for different breast characteristics and X-ray *** calculated a series of D_(gN)^(DBT) values for breasts with different percentage mass glandularities(5%,25%,50%,75%,and 1.0%)and compressed breast thicknesses(2,3,4,5,6,and 7 cm)at various tube potentials(25,28,30,32,35,and 49 kV)and target/filter combinations(W/Rh,W/Al,Mo/Mo,Rh/Rh,and Rh/Ag).The parameter dependence of the breast characteristics and beam conditions on D_(gN)^(DBT) in detailed breast models was *** D_(gN)^(DBT) results were 1..6-51.0%lower than those of the traditional dosimetry standard in *** difference in D_(gN)^(DBT) was mainly due to a decrease in the depth of the main energy deposition area caused by the glandular distribution along the depth *** results obtained in this study may be used to improve breast dosimetry in China and provide more detailed information on risk assessment during DBT.

关键词： Digital breast tomosynthesis Normalized glandular dose coefficients Detailed breast model Monte Carlo simulation

A review of ultrafast laser micro/nano fabrication:Material processing,surface/interface controlling,and devices fabrication

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Nano Research 2024年第7期17卷 6212-6230页

作者： Heng Guo Jiawang Xie Guangzhi He Dezhi Zhu Ming Qiao Jianfeng Yan Jiachen Yu Jiaqun Li Yuzhi Zhao Ma Luo Haoze Han State Key Laboratory of Tribology in Advanced Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China

Ultrafast laser processing technology has offered a wide range of opportunities in micro/nano fabrication and other fields such as nanotechnology,biotechnology,energy science,and photonics due to its controllable processing precision,diverse processing capabilities,and broad material *** processing abilities and applications of the ultrafast laser still need more *** the field of material processing,controlling the atomic scale structure in nanomaterials is *** effects exist in ultrafast laser surface/interface processing,making it difficult to modulate the nanostructure and properties of the surface/interface as *** the ultrafast laser fabrication of micro functional devices,the processing ability needs to be ***,we review the research progress of ultrafast laser micro/nano fabrication in the areas of material processing,surface/interface controlling,and micro functional devices *** useful ultrafast laser processing methods and applications in these areas are *** various processing effects and abilities,the ultrafast laser processing technology has demonstrated application values in multiple fields from science to industry.

关键词： ultrafast laser micro/nano fabrication material processing surface/interface controlling devices fabrication