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Single-atom Zn confined in hierarchical hollow microstructure as an acid/base-resistant microwave absorption materials

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Nano Research 2024年第8期17卷 6785-6794页

作者： Yue Lou Jiao Li Xiaokun Li Zhenyu Zhu zhan Shi biao Xu School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012China

Developing acid/base-resistant and low-price microwave-absorbing materials with lighter weight is highly desired for practical applications in extreme ***,we demonstrate the successful synthesis of the N-doped porous carbon(NC)material with hierarchical pore structure by the spray pyrolysis *** large specific surface area(SBET=707.53 m^(2)·g^(−1))of materials enables multiple scattering of incident electromagnetic waves,and N doping greatly enhances the electrical conductivity of the ***,single-atom Zn can adjust the local electronic structure of adjacent sites such as carbon and nitrogen atoms,induce the center of polarization,and thus change the dielectric and electronic properties of the host *** porous carbon coating of single-atom Zn avoids the deterioration of electromagnetic parameters caused by the accumulation of magnetic particles under high-temperature *** the same time,they can also be used in various complex environments,such as acidic and basic ***,NC-1000,with high surface area,low density,and good chemical stability,obtained a minimum reflection loss(RLmin)of−50.5 dB and an effective absorption bandwidth(EAB)exceeding 5.1 GHz at the thickness of 1.9 *** soaking in the strong acid and base solution,the electromagnetic wave absorption performance of the material decreased by<15%.Widely available raw materials and a simple preparation scheme are expected to expedite industrial mass production for this novel type of materials.

关键词： hierarchical hollow microstructure microwave absorption metal-organic framework(MOF) impedance matching singleatom Zn acid/base-resistant

Miniaturized, Shared Electric and Magnetic Dipole, Pattern Diversity IoT Antenna for Sub-6 GHz Applications

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Chinese Journal of Electronics 2024年第5期33卷 1224-1233页

作者： zhan wang Yuandan DONG University of Electronic Science and Technology of China

By using a novel meta-resonator structure, a miniaturized, surface mountable, shared aperture, and hybrid electric/magnetic dipole pattern diversity antenna is proposed for Internet of things（IoT） applications. By exploring the shared electric（E-dipole） and magnetic dipole（M-dipole） structures, a novel T-shaped split-ring resonator（SRR） with even and odd modes is presented and studied by current distributions and equivalent *** and omnidirectional（monopole-like） patterns are achieved by exciting the M-dipole and E-dipole modes of the T-shaped SRR, respectively. To validate the proposed design, this shared aperture metamaterial-inspired pattern diversity antenna with a small size of 0.295λ0× 0.0065λ0× 0.115λ0is fabricated and measured. The measured overlapped-10 dB bandwidth is from 3.40 GHz to 3.63 GHz（7.0%, covering the LTE B42 band） and the port isolation is greater than 23 dB. Both two modes achieve a good radiation efficiency better than-0.79 d B（>83.0%）.

关键词： Antenna measurements Dipole antennas Surface mount technology Switches Size measurement Aperture antennas Internet of Things Electric/magnetic dipoles Internet of things (IoT) Metamaterial-based/inspired antenna LOW-PROFILE PATCH ANTENNA RECONFIGURABLE ANTENNA MICROSTRIP ANTENNA RADIATION-PATTERN HIGH-GAIN FREQUENCY ARRAY

Clinical efficacy and mechanism study of mid-frequency anti-snoring device in treating moderate obstructive sleep apnea-hypopnea syndrome

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World Journal of Clinical Cases 2024年第5期12卷 942-950页

作者： Bao Qian zhan-Jun Chen Yong-Sheng wang Xiao-Yan Hu Xiao-biao Hu Yong-Hua Zheng Pulmonary Medicine Shanghai Jinshan Tinglin HospitalShanghai 201505China Radiology Medicine Shanghai Jinshan Tinglin HospitalShanghai 201505China

BACKGROUND Obstructive sleep apnea-hypopnea syndrome(OSAHS)is primarily caused by airway obstruction due to narrowing and blockage in the nasal and nasopha-ryngeal,oropharyngeal,soft palate,and tongue base *** mid-frequency anti-snoring device is a new technology based on sublingual nerve *** principle is to improve the degree of oropharyngeal airway stenosis in OSAHS patients under mid-frequency wave ***,there is a lack of clinical application and imaging *** We selected 50 patients diagnosed with moderate OSAHS in our hospital between July 2022 and August *** underwent a 4-wk treatment regimen involving the mid-frequency anti-snoring device during nighttime *** the treatment,we monitored and assessed the sleep apnea quality of life index and Epworth Sleepiness Scale ***,we performed computed tomo-graphy scans of the oropharynx in the awake state,during snoring,and while using the mid-frequency anti-snoring ***-sectional area measurements in different states were taken at the narrowest airway point in the soft palate posterior and retrolingual *** Compared to pretreatment measurements,patients exhibited a significant reduction in the apnea-hypopnea index,the percentage of time with oxygen saturation below 90%,snoring frequency,and the duration of the most prolonged apnea *** lowest oxygen saturation showed a notable increase,and both sleep apnea quality of life index and Epworth Sleepiness Scale scores *** computed tomography scans revealed that in OSAHS patients cross-sectional areas of the oropharyngeal airway in the soft palate posterior area and retrolingual area decreased during snoring compared to the awake ***,during mid-frequency anti-snoring device treatment,these areas increased compared to *** The mid-frequency anti-snoring device demonstrates the potential to enhance various sleep parameters in pat

关键词： Mid-frequency anti-snoring device Obstructive sleep apnea-hypopnea syndrome Sleep monitoring Oropharyngeal computed tomography Curative effect

Influence of crystal-transforming agent on the performance and mechanism ofα-high-strength gypsum prepared from FGD gypsum

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Particuology 2024年第4期87卷 37-45页

作者： Zhuoyue Xu Xiao wang biao Jin Dawang zhang Hui Li College of Materials Science and Engineering Xi'an University of Architecture and TechnologyXi'an710055China Schoolof Materials and Chemical Engineering Henan University of Urban ConstructionPingdingshan46736China

This paper investigates the impact of flue gas desulfurization(FGD)gypsum's crystal modifier on the characteristics and microcosmic mechanism ofα-high strength *** results demonstrate that all three crystal modifiers can convert FGD gypsum toα-high-strength *** acid(CA)has the most significant influence onα-high-strength gypsum,and the preparedα-high-strength gypsum is short columnar,with an aspect ratio in the range of 1-3,and has a faster setting time,a larger specific surface area,and a smaller standard consistency,higher compressive strength,greater surface hardness,and smaller crystal particle *** initial setting time of theα-high-strength gypsum manufactured with CA crystal modifier was decreased by 36%compared to the blank sample,the final setting time was lowered by 37.5%,and the water consumption of the standard consistency was reduced by 8%.The maximum strength is 32 MPa after 2 h,the absolute dry compressive strength is up to 38 MPa,and the surface hardness is improved by 24.43%.

关键词： Flue gas desulfurization gypsum Crystal modifier Microscopic mechanism α-high-strength gypsum

Surface integrity evolution during creep feed profile grinding ofγ-TiAl blade tenon

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Chinese Journal of Aeronautics 2024年第8期37卷 496-512页

作者： Tao CHEN Xiaowei wang biao ZHAO Wenfeng DING Jiuhua XU National Key Laboratory of Science and Technology on Helicopter Transmission Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Gamma titanium-aluminum(γ-TiAl)intermetallic compounds are increasingly used in manufacturing key hot-end components(e.g.,blade tenon)in aero engines due to their high specific strength and lightweight *** feed profile grinding(CFPG)as a crucial precision process that is applied to produce the final profile of the blade ***,sudden surface burns and microcracks of machined c-TiAl blade tenon often occur because of its low plasticity and high strength during grinding processes,leading to poor surface *** this work,CFPG experiments based on the profile characteristics ofγ-TiAl blade tenon were performed and an associated undeformed chip thickness model considering grain–workpiece contact condition was established to explore the evolution of the surface ***,the surface integrity was analyzed at different positions of the blade tenon in terms of surface roughness and morphology,metallographic structure,microhardness,and residual *** show that the profile characteristics of blade tenon have a significant influence on machined surface integrity because of the thermomechanical effect at various detecting *** residual stress was established based on the undeformed chip thickness model considering the profile structure,with a prediction error of 10%–15%.The thermomechanical effect is more obvious at the bottom area,where the surface roughness,work hardening degree,and subsurface plastic deformation range are the largest,while the values at the bevel area are the *** on the undeformed chip thickness model,a residual stress finite element simulation was conducted by employing thermomechanical coupled *** addition,the error between the simulation and the experiment was between 10%–15%.Strain and strain rate equations were established through the relationship between material displacement and *** average strain and strain rate of the ground surface when ap is 1.0 mm are 18.8%and 33.2%l

关键词： Gamma titanium-aluminum intermetallic compounds Blade tenon Creep feed profile grinding Surface integrity Thermomechanical effect

Thermal Performance of a 4 K High-Frequency Pulse Tube Cryocooler with Different Working Fluids

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Journal of Thermal Science 2024年第4期33卷 1468-1479页

作者： GAO Zhaozhao YANG biao FAN Xiaoyu CHEN Liubiao wang Junjie Key Laboratory of Cryogenic Science and Technology Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China

The high-frequency pulse tube cryocooler(HPTC)represents a promising miniature cryocooling technology due to its compact structure and the absence of low-temperature moving ***,limited to the non-ideal gas effect of4He,the HPTC is hard to obtain high cooling performance in the liquid helium temperature range.3He as the working fluid can effectively improve the cooling performance of the HPTC,but the high cost hinders its wide *** consideration of both cooling performance and cost-effectiveness,this paper explores the feasibility of utilizing^(3)He-^(4)He mixtures as the working fluid for ***,the experimental results of a developed HPTC based4He are *** a total power consumption of 575 W,the lowest temperature of 3.26 K was *** the measured cooling power at 4.2 K was 20.8 *** the theoretical utmost efficiency of the cryocooler was calculated in terms of the thermophysical properties of the working fluids,using ^(3)He-^(4)He mixtures with different compositions as the working *** whole machine modeling of the HPTC was further carried out,and the influence of the working fluids with different components on the structural parameters such as double-inlet and inertance tube,and operating parameters such as pressure and frequency were *** calculated results show that the cooling power is expected to be increased to36 mW and 53 mW if the equimolar ^(3)He-^(4)He mixture and pure ^(3)He are used,respectively.

关键词： high-frequency pulse tube cryocooler ^(3)He-^(4)He mixture liquid helium temperature thermally coupled

维普期刊数据库

Creep-Resistant Covalent Adaptable Networks with Excellent SelfHealing and Reprocessing Performance via Phase-Locked Dynamic Covalent Benzopyrazole-Urea Bonds

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Chinese Journal of Polymer Science 2024年第10期42卷 1545-1556,I0013页

作者： Miao Xie Xiao-Rong wang zhan-Hua wang He-Sheng Xia State Key Laboratory of Polymer Materials Engineering Polymer Research InstituteSichuan UniversityChengdu610065China School of Petrochemical Engineering Liaoning Petrochemical UniversityFushun113001China

Covalent adaptive networks(CANs)are capable of undergoing segment rearrangement after being heated,which endows the materials with excellent self-healing and reprocessing performance,providing an efficient solution to the environment pollution caused by the plastic *** main challenge remains in developing CANs with both excellent reprocessing performance and creep-resistance *** this study,a series of CANs containing dynamic covalent benzopyrazole-urea bonds were developed based on the addition reaction between benzopyrazole and isocyanate *** calculation confirmed that relatively low dissociation energy is obtained through undergoing a five-member ring transition state,confirming excellent dynamic property of the benzopyrazole-urea *** verified by the FTIR results,this nice dynamic property can be well maintained after incorporating the benzopyrazole-urea bonds into polymer *** self-healing and reprocessing performance is observed by the 3-ABP/PDMS elastomers owing to the dynamic benzopyrazole-urea *** separation induced by the aggregation of the hard segments locked the benzopyrazole-urea bonds,which also makes the elastomers display excellent creep-resistance *** hard phase locking strategy provides an efficient approach to design CANs materials with both excellent reprocessing and creep-resistance performance.

关键词： Covalent adaptive networks Self-healing polymer Dynamic covalent bond

维普期刊数据库

Predicting Rock Burst in Underground Engineering Leveraging a Novel Metaheuristic-Based LightGBM Model

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Computer Modeling in Engineering & Sciences 2024年第7期140卷 229-253页

作者： Kai wang biao He Pijush Samui Jian Zhou No.Three Engineering Co. Ltd.CCCC First Highway Engineering CompanyBeijing101102China Department of Civil Engineering Faculty of EngineeringUniversiti MalayaKuala Lumpur50603Malaysia Department of Civil Engineering National Institute of Technology PatnaBihar800005India School of Resources and Safety Engineering Central South UniversityChangsha410083China

Rock bursts represent a formidable challenge in underground engineering,posing substantial risks to both infrastructure and human *** sudden and violent failures of rock masses are characterized by the rapid release of accumulated stress within the rock,leading to severe seismic events and structural ***,the development of reliable prediction models for rock bursts is paramount to mitigating these *** study aims to propose a tree-based model—a Light Gradient Boosting Machine(LightGBM)—to predict the intensity of rock bursts in underground engineering.322 actual rock burst cases are collected to constitute an exhaustive rock burst dataset,which serves to train the *** population-basedmetaheuristic algorithms are used to optimize the hyperparameters of the LightGBM ***,the sensitivity analysis is used to identify the predominant factors that may incur the occurrence of rock *** results show that the population-based metaheuristic algorithms have a good ability to search out the optimal hyperparameters of the LightGBM *** developed LightGBM model yields promising performance in predicting the intensity of rock bursts,with which accuracy on training and testing sets are 0.972 and 0.944,*** sensitivity analysis discloses that the risk of occurring rock burst is significantly sensitive to three factors:uniaxial compressive strength(σc),stress concentration factor(SCF),and elastic strain energy index(Wet).Moreover,this study clarifies the particular impact of these three factors on the intensity of rock bursts through the partial dependence plot.

关键词： Rock burst prediction LightGBM coati optimization algorithm pelican optimization algorithm partial dependence plot

An NIR-II-emissive Ru(II) metallacycle for efficient and safe immunotherapy

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Science China Chemistry 2024年

作者： Chonglu Li Jianbo zhan biao Dong Institute of Health Inspection and Testing Hubei Provincial Center for Disease Control and Prevention State Key Laboratory on Integrated Optoelectronics College of Electronic Science and Engineering Jilin University

Immunotherapy, as a groundbreaking cancer treatment, has gained considerable attention for its utilization of the body’s immune system to combat tumors [1]. This therapy induces tumor cell apoptosis, triggering a sustained anti-tumor immune response and effectively preventing tumor recurrence and metastasis [2]. The fundamental principle lies in inducing tumor cell death through specific treatment modalities,leading to the release of a cascade of signaling molecules and antigens, thereby mobilizing the immune system to actively identify and attack tumor cells [3].

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