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Science China(Information Sciences) 2024年第2期67卷 267-278页

作者： Guofang YU Renrong LIANG Haiming zhao Lei XIAO Jie CUI Yue zhao Wenpu CUI Jing WANG jun XU jun fu Tianling REN School of Integrated Circuits Tsinghua University Beijing National Research Center for Information Science Technology Tsinghua University

Surface acoustic wave(SAW) resonators with an ultrahigh Q-factor are designed and fabricated on silicon-based gallium nitride(GaN/Si). The temperature-dependent performance is characterized over a wide range, from 10 to 500 K. Finite element analysis is employed to guide the design of the SAW resonator from indications of the Rayleigh mode and weak propagation direction dependence of SAW in the c-plane of GaN/Si. The SAW resonator with 100 pairs of interdigital transducers(IDT), 100 pairs of grating reflectors(GR) for each side, aperture size of 80 μm, metallization ratio of 0.5, and electrode width of 500 nm resonates at 1.9133 GHz accordingly with an ultrahigh Q-factor of 7622 at room temperature, which contributes the fr× Qr, up to 14.583×1012Hz. A resonator operating over 10 to 500 K indicates an approximately linear decreasing temperature dependence above 280 K while being approximately constant below 40 K. The fitting to resonator characteristics using the modified Butterworth Van Dyke(m BVD) model reveals a reduction in both the electrode and mechanical losses while worsening the dielectric loss with cooling down.

关键词： GaN/Si SAW resonator ultrahigh Q-factor temperature-dependent performance mBVD losses

Hydrogel-Assisted Electrokinetics for High-Resolution and Non-invasive Flow Monitoring in Microfluidic Chips

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Chinese Journal of Chemistry 2024年第6期42卷 571-577页

作者： Na zhao Yanni Ma Zehua Yu jun Huang Xiangqian fu Tao Qiu Kang Liu MOE Key Laboratory of Hydraulic Machinery Transients School of Power and Mechanical EngineeringWuhan UniversityWuhanHubei430072 China Department of Urology Renmin Hospital of Wuhan UniversityWuhanHubei430072 China Department of Organ Transplantation Renmin Hospital of Wuhan UniversityWuhanHubei430072 China

Convenient non-invasive flow monitoring would facilitate the operation and control in microfluidic chips,but is challenging due to the small space of microchannels and complex operation required in traditional optical *** this work,we propose a novel non-invasive strategy to probe microfluidic flows via streaming potential *** sealing one side of the microchannel with a piece of hydrogel film,streaming potential inside the channel can be clearly detected by electrodes at outer surface of the hydrogel due to ion diffusion in the *** is detected without sensors contacting with the internal ***,the electrodes shape like a tiny probe,which can move around mapping the flow distribution in a chip with the spatial resolution of 1 mm and flow rate detection limit of 3μL·min–*** inside the channels can also be detected,due to the fluctuation of streaming voltage when gas-liquid interface flows through the electrode,showing an easy and potential way for multi-functional flow monitoring in microfluidic chips.

关键词： Microfluidics Hydrogels Electrokinetics Flow monitoring Non-invasive Sensor Charge transport

A stochastic gradient-based two-step sparse identification algorithm for multivariate ARX systems

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Control Theory and Technology 2024年第2期22卷 213-221页

作者： Yanxin fu Wenxiao zhao Key Laboratory of Systems and Control Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing100049China

We consider the sparse identification of multivariate ARX systems, i.e., to recover the zero elements of the unknown parameter matrix. We propose a two-step algorithm, where in the first step the stochastic gradient (SG) algorithm is applied to obtain initial estimates of the unknown parameter matrix and in the second step an optimization criterion is introduced for the sparse identification of multivariate ARX systems. Under mild conditions, we prove that by minimizing the criterion function, the zero elements of the unknown parameter matrix can be recovered with a finite number of observations. The performance of the algorithm is testified through a simulation example.

关键词： ARX system Stochastic gradient algorithm Sparse identification Support recovery Parameter estimation Strong consistency

Geometric Probability on a Lattice with the 15th Type of Convex Pentagon as a fundamental Region

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Acta Mathematica Sinica,English Series 2024年

作者： Jiang fu zhao jun JIANG Hai LIU National Engineering Research Center for E-learning Central China Normal University College of Science Wuhan University of Science and TechnologyHubei Province Key Laboratory of Systems Science in Metallurgical Process Department of Mathematics and Physics Fujian Jiangxia University

In 2015, a group of mathematicians at the University of Washington, Bothell, discovered the15th pentagon that can cover a plane, with no gaps and overlaps. However, research on its containment measure theory or geometric probability is limited. In this study, the Laplace extension of Buffon’s problem is generalized to the case of the 15th pentagon. In the solving process, the explicit expressions for the generalized support function and containment function of this irregular pentagon are *** addition, the chord length distribution function and density function of random distance of this pentagon are obtained in terms of the containment function.

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Prospect of ultrahigh-resolution fast neutron absorption spectroscopy based on a laser plasma electron accelerator

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High Power Laser Science and Engineering 2024年第1期12卷 108-115页

作者： Wen-zhao Wang Jie Feng Xiao-Peng Zhang Yao-jun Li Wei-jun Zhou Wen-Chao Yan Guo-Qiang Zhang Chang-Bo fu Li-Ming Chen Key Laboratory of Laser Plasma(MoE) School of Physics and AstronomyShanghai Jiao Tong UniversityShanghaiChina IFSA Collaborative Innovation Center Shanghai Jiao Tong UniversityShanghaiChina Institute of High Energy Physics Chinese Academy of SciencesBeijingChina Shanghai Advanced Research Institute Chinese Academy of SciencesShanghaiChina Key Laboratory of Nuclear Physics and Ion-beam Application(MoE) Institute of Modern PhysicsFudan UniversityShanghaiChina

Fast neutron absorption spectroscopy is widely used in the study of nuclear structure and element analysis. However,due to the traditional neutron source pulse duration being of the order of nanoseconds, it is difficult to obtain a high-resolution absorption spectrum. Thus, we present a method of ultrahigh energy-resolution absorption spectroscopy via a high repetition rate, picosecond duration pulsed neutron source driven by a terawatt laser. The technology of single neutron count is used, which results in easily distinguishing the width of approximately 20 keV at 2 MeV and an asymmetric shape of the neutron absorption peak. The absorption spectroscopy based on a laser neutron source has one order of magnitude higher energy-resolution power than the state-of-the-art traditional neutron sources, which could be of benefit for precisely measuring nuclear structure data.

关键词： fast neutron absorption spectroscopy laser plasma accelerator photo-nuclear neutrons single neutron count

Efficacy of stepwise mini-incision microdissection testicular sperm extraction for nonobstructive azoospermia with varied etiologies

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Asian Journal of Andrology 2023年第5期25卷 621-626页

作者： Yu-Xiang Zhang Chen-Cheng Yao Yu-Hua Huang Peng Li Er-Lei Zhi Zi-Jue Zhu Jian-Xiong Zhang fu-jun zhao Zheng Li Ru-Hui Tian Department of Andrology The Center for Men's HealthUrologic Medical CenterShanghai Key Laboratory of Reproductive MedicineShanghai General HospitalShanghai Jiao Tong University School of MedicineShanghai 200080China

Stepwise mini-incision microdissection testicular sperm extraction(mTESE)is a procedure that attempts to minimize testicular ***,the mini-incision approach may vary in patients with different ***,we performed a retrospective analysis of 665 men with nonobstructive azoospermia(NOA)who underwent stepwise mini-incision mTESE(Group 1)and 365 men who underwent standard mTESE(Group 2).The results showed that the operation time(mean±standard deviation)for patients with successful sperm retrieval in Group1(64.0±26.6min)was significantly shorter than that in Group2(80.2±31.3min),with P0.05),even when the etiologies of NOA were taken into *** results of consecutive multivariate logistic regression analysis(odds ratio[0R]:0.57;95%confidence interval[Cl]:0.38-0.87;P=0.009)and receiver operating characteristic(ROC)analysis(area under the ROC curve[AUC]=O.628)showed that preoperative anti-Mullerian hormone(AMH)level in idiopathic NOA patients was a potential predictor for surgical outcomes after initial three small incisions made in the equatorial region without sperm examined under an operating microscope(Steps 2-4).In conclusion,stepwise mini-incision mTESE is a useful technique for NOA patients,with comparable SRR,less surgical invasiveness,and shorter operation time compared with the standard *** AMH levels may predict successful sperm retrieval in idiopathic patients even after a failed initial mini-incision procedure.

关键词： etiology male infertility nonobstructive azoospermia standard mTESE stepwise mini-incision mTESE

Health risk assessment of heavy metal pollution in groundwater of a karst basin,SW China

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Journal of Groundwater Science and Engineering 2024年第1期12卷 49-61页

作者： fu-ning Lan Yi zhao jun Li Xiu-qun Zhu Karst Ecosystem National Observation and Research StationPingguo 531406GuangxiChina Institute of Karst Geology International Research Centre on KarstUnder the Auspices of UNESCOGuangxi Karst Resources and Environment Research Center of Engineering TechnologyChinese Academy of Geological SciencesKarst Dynamics LaboratoryMNR and GuangxiGuilin 541004China Hebei Key Laboratory of Water Quality Engineering and Comprehensive Utilization of Water Resources Hebei University of ArchitectureZhangjiakou 075000Hebei ProvinceChina College of Hydrology and Water Resources Hohai UniversityNanjing 210098China

To investigate the presence of metal elements and assess their health risk for the populace in the Nandong Underground River Basin(NURB),we conducted an analysis of eleven common heavy metals in the water body.A Health risk assessment(HRA)model was employed to analyze 84 water samples from the *** detection results revealed the following order of heavy metals concentrations:Fe>Al>Mn>Zn>As>Cd>Pb>Cr>Ni>Cu>*** analysis indicated a certain similarity in material source and migration transformation among these eleven metal *** study identified that the health risks for local residents exposed to metal elements in the water of NURB primarily stem from carcinogenic risk(10^(−6)–10^(−4)a^(−1))through the drinking water ***,the health risk of heavy metal exposure for children through drinking water was notably higher than for *** maximum health risks of Cr in both underground and surface water exceeded the recommendation standard(5.0×10^(−5)a^(−1))from ICRP,surpassing the values recommended by the Swedish Environmental Protection Agency,the Dutch Ministry of Construction and Environment and the British Royal Society(5.0×10^(−6)a^(−1)).The results of the health risk assessment indicate that Cr in the water of NURB is the primary source of carcinogenic risk for local residents,followed by Cd and ***,it is imperative to control these three carcinogenic metals when the water was used as drinking water resource.

关键词： Water Pollution Correlation Analysis Toxicity of Heavy Metal Elements Underground River Basin Carcinogenicity Potential

Biomarkers in aortic dissection:Diagnostic and prognostic value from clinical research

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Chinese Medical Journal 2024年第3期137卷 257-269页

作者： Yufei zhao Weiguo fu Lixin Wang Department of Vascular Surgery Zhongshan HospitalFudan UniversityShanghai 200032China Vascular Surgery Institute Zhongshan HospitalFudan UniversityShanghai 200032China National Clinical Research Center for Interventional Medicine Zhongshan HospitalFudan UniversityShanghai 200032China Department of Vascular Surgery Xiamen BranchZhongshan HospitalFudan UniversityXiamenFujian 361015China

Aortic dissection is a life-threatening condition for which diagnosis mainly relies on imaging examinations,while reliable biomarkers to detect or monitor are still under *** advances in technologies provide an unprecedented opportunity to yield the identification of clinically valuable biomarkers,including proteins,ribonucleic acids(RNAs),and deoxyribonucleic acids(DNAs),for early detection of pathological changes in susceptible patients,rapid diagnosis at the bedside after onset,and a superior therapeutic regimen primarily within the concept of personalized and tailored endovascular therapy for aortic dissection.

关键词： Aortic dissection Biomarker Protein Cell-free DNA miRNA Inflammation Lipid-metabolism

Effect of Wave Nonlinearity on the Instantaneous Seabed Liquefaction

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China Ocean Engineering 2024年第1期38卷 93-103页

作者： WANG zhao-jun SUI Ti-ti ZHANG Chi PAN jun-ning Key Laboratory of Port Waterway and Sedimentation Engineering of the Ministry of TransportNanjing Hydraulic Research InstituteNanjing 210024China Key Laboratory of Coastal Disaster and Protection(Hohai University) Ministry of EducationNanjing 210098China The National Key Laboratory of Water Disaster Prevention Nanjing 210098China

The nonlinear variation of wave is commonly seen in nearshore area,and the resulting seabed response and liquefaction are of high concern to coastal *** this study,an analytical formula considering the nonlinear wave skewness and asymmetry is adopted to provide wave pressure on the seabed *** liquefaction depth attenuation coefficient and width growth coefficient are defined to quantitatively characterize the nonlinear effect of wave on seabed *** on the 2D full dynamic model of wave-induced seabed response,a detailed parametric study is carried out in order to evaluate the influence of the nonlinear variation of wave loadings on seabed ***,new empirical prediction formulas are proposed to fast predict the maximum liquefaction under nonlinear *** indicate that(1)Due to the influence of wave nonlinearity,the vertical transmission of negative pore water pressure in the seabed is hindered,and therefore,the amplitude decreases significantly.(2)In general,with the increase of wave nonlinearity,the liquefaction depth of seabed decreases *** under asymmetric and skewed wave loading,the attenuation of maximum seabed liquefaction depth is the most significant among all the nonlinear wave ***,highly skewed wave can cause the liquefaction depth of seabed greater than that under linear wave.(3)The asymmetry of wave pressure leads to the increase of liquefaction width,whereas the influence of skewedness is not significant.(4)Compared with the nonlinear waveform,seabed liquefaction is more sensitive to the variation of nonlinear degree of wave loading.

关键词： nonlinear wave seabed response seabed liquefaction numerical simulation liquefaction prediction

A novel small-signal equivalent circuit model for GaN HEMTs incorporating a dual-field-plate

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Journal of Semiconductors 2024年第5期45卷 61-68页

作者： Jinye Wang jun Liu Zhenxin zhao School of Integrated Circuit Science and Engineering Hangzhou Dianzi UniversityHangzhou 310018China

An accurate and novel small-signal equivalent circuit model for GaN high-electron-mobility transistors(HEMTs)is proposed,which considers a dual-field-plate(FP)made up of a gate-FP and a *** equivalent circuit of the overall model is composed of parasitic elements,intrinsic transistors,gate-FP,and source-FP *** equivalent circuit of the gate-FP is identical to that of the intrinsic *** order to simplify the complexity of the model,a series combination of a resistor and a capacitor is employed to represent the *** analytical extraction procedure of the model parameters is presented based on the proposed equivalent *** verification is carried out on a 4×250μm GaN HEMT device with a gate-FP and a source-FP in a 0.45μm *** with the classic model,the proposed novel small-signal model shows closer agreement with measured S-parameters in the range of 1.0 to 18.0 GHz.

关键词： small-signal model dual field-plate(FP) GaN high-electron-mobility transistors(HEMT) parameter extraction