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Ultralow-phase-noise and broadband frequency-hopping coupled optoelectronic oscillator under quiet point operation

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Photonics Research 2024年第08期12卷 1785-1793页

作者： hui LIU MINGYANG GUO TIAN ZHANG jian DAI KUN XU State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications School of Electronic Engineering Beijing University of Posts and Telecommunications

Advancements in microwave photonics have yielded novel approaches for generating high-purity microwave sources. Among these, optoelectronic oscillators（OEOs） and coupled optoelectronic oscillators（COEOs） have demonstrated the capability to generate frequency-independent microwaves with exceptionally low phase ***, the tunability of the oscillators is rather limited due to the necessity for narrowband electronic bandpass filters, presenting challenges in achieving both wide and rapid tuning capabilities. Here, we present a COEO featuring ultralow phase noise, flexible tuning capability, and high robustness. This is achieved through a quiet point（QP）-operated harmonic mode-locked fiber laser, which effectively mitigates optical amplifier noise and supermode competition, thus significantly diminishing the necessity for ultra-narrow electronic filters. Due to the liberated tuning ability, we present an oscillator that can be tuned from 2 GHz to 18 GHz, with phase noise as low as-140 d Bc/Hz at 10 k Hz under the QP operation. We then illustrate the practical application of the proposed oscillator in generating frequency-hopping signals with consistent spurious modes less than-85 d Bc,absolute phase noise below-135 d Bc/Hz at 10 k Hz, hopping resolution of 1.25 MHz, and fractional frequency stability below 6.1 × 10-12at 1 s averaging time when locked to a reference. The presented COEO structure emerges as a compelling solution for agile and low-noise microwave sources in advanced wireless communication and radar systems.

关键词： Bandpass filters Beam splitters Microwave photonics Mode-locked fiber lasers Optical amplifiers Phase noise

Interface strengthening for thermal sprayed WC-10Co4Cr coating subjected to pulsed magnetic treatment

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Rare Metals 2024年第2期43卷 780-795页

作者： Cheng-Kai Qian Qu Liu Heng Wang Ke-jian Li Zhi-Peng cai Department of Mechanical Engineering Tsinghua UniversityBeijing100084China Tianjin Research Institute for Advanced Equipment Tsinghua UniversityTianjin300304China State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing100084China

The reliability of the coated industry components demands ideal fatigue properties of the coating,and it is mainly determined by the performance of the *** this study,pulsed magnetic treatment(PMT)was applied to the thermal sprayed WC-10Co4Cr coating,and the fatigue lifetime of the coated bolt increased by 219.82%under an imitation of the operating mode *** tests further proved that both the adhesion and cohesion strength were improved after PMT,and they benefit from the interface strengthening *** formation of coherent WC/Co interfaces was characterized by in-situ transmission electron microscopy(TEM),and the molecular dynamic simulations indicate that the work of separation of these interfaces is much higher than the original disordered *** stress was relaxed and distributed more homogeneously after PMT,and it mainly contributes to the coating/substrate *** work provides a new post-treatment method focusing on the interfaces in the WC-based coating and gives insight into its mechanism so that it is hopeful to be applied to other kinds of coatings.

关键词： Cemented carbide coating Pulsed magnetic treatment Interface strengthening Fatigue properties Adhesion strength

Vibration Suppression for Active Magnetic Bearings Using Adaptive Filter with Iterative Search Algorithm

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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 61-71页

作者： Jin-hui Ye Dan Shi Yue-Sheng Qi Jin-hui Gao jian-Xin Shen IEEE Department of Electrical Engineering Zhejiang UniversityHangzhou 310027China CES and IEEE

Active Magnetic Bearing(AMB) is a kind of electromagnetic support that makes the rotor movement frictionless and can suppress rotor vibration by controlling the magnetic force. The most common approach to restrain the rotor vibration in AMBs is to adopt a notch filter or adaptive filter in the AMB controller. However, these methods cannot obtain the precise amplitude and phase of the compensation current. Thus, they are not so effective in terms of suppressing the vibrations of the fundamental and other harmonic orders over the whole speed range. To improve the vibration suppression performance of AMBs,an adaptive filter based on Least Mean Square(LMS) is applied to extract the vibration signals from the rotor displacement signal. An Iterative Search Algorithm(ISA) is proposed in this paper to obtain the corresponding relationship between the compensation current and vibration signals. The ISA is responsible for searching the compensating amplitude and shifting phase online for the LMS filter, enabling the AMB controller to generate the corresponding compensation force for vibration suppression. The results of ISA are recorded to suppress vibration using the Look-Up Table(LUT) in variable speed range. Comprehensive simulations and experimental validations are carried out in fixed and variable speed range, and the results demonstrate that by employing the ISA, vibrations of the fundamental and other harmonic orders are suppressed effectively.

关键词： Active Magnetic Bearing(AMB) Adaptive filter Iterative search algorithm Least mean square(LMS) Vibration suppression

Interface interaction between SiO_(2) and magnetite under high temperature:particle migration and inhibition mechanism

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Journal of Iron and Steel Research International 2024年第3期31卷 561-572页

作者： Yao-zu Wang jian-liang Zhang Qiang Cheng hui-qing jiang Zheng-jian Liu Yu-bo Tan School of Intelligent Science and Technology University of Science and Technology BeijingBeijing 100083China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China School of Advanced Engineering University of Science and Technology BeijingBeijing 100083China

Silicon is one of the main gangue components in iron ore,usually in the form of quartz and *** studies have shown that SiO_(2) has a two-sided effect on the consolidation of pellets during high-temperature oxidation roasting of ***,it is very difficult to capture the structural evolution and migration mechanisms during high-tem-perature roasting process by existing experimental ***,the influence of SiO_(2) on the consolidation behavior of magnetite was studied through a series of roasting experiments and molecular dynamic *** results show that the consolidation index and particle growth index decrease with the increase in SiO_(2) content in the *** 1573 K,the liquid phase promotes the recrystallization growth of hematite at high *** dynamic study shows that it is difficult for quartz SiO_(2) to form sintering neck with Fe_(2)O_(3).When the calcination temperature is higher than 1400 K,the Fe_(2)O_(3)-Fe_(2)SiO_(4) system produces a considerable sintering neck structure after *** atomic migration ability of Fe_(2)SiO_(4) is much higher than that of Fe_(2)O_(3).The higher atomic migration ability of Fe_(2)SiO_(4) is the main reason for the formation of the sintering neck.

关键词： Sintering neck Crystal growth Consolidation Molecular dynamics SiO_(2)

Theoretical understanding of correlation between magnetic phase transition and the superconducting dome in high-Tc cuprates

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 167-173页

作者： Chen Zhang cai-Xin Zhang Su-Huai Wei Haiqing Lin hui-Xiong Deng State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Beijing Computational Science Research Center Beijing 100193China

Many issues concerning the origin of high-temperature superconductivity(HTS)are still under *** example,how the magnetic order varies with doping and its relationship with the superconducting temperature(Tc);and why Tcalways peaks near the quantum critical *** this paper,taking hole-doped La_(2)CuO_(4)as a classical example,we employ the first-principles band structure and total energy calculations with Monte Carlo simulations to explore how the symmetry-breaking magnetic ground state evolves with hole doping and the origin of a dome-shaped superconductivity region in the phase *** demonstrate that the local antiferromagnetic order and doping play key roles in determining the electron-phonon coupling,thus ***,the La_(2)CuO_(4)possesses a checkerboard local antiferromagnetic ground *** the hole doping increases,Tcincreases with the enhanced electron-phonon coupling *** as the doping increases further,the strength of the antiferromagnetic interaction weakens and spin fluctuation *** the critical doping level,a magnetic phase transition occurs that reduces the local antiferromagnetism-assisted electron-phonon coupling,thus diminishing the *** superconductivity disappears in the heavily overdoped region when the ferromagnetic order *** observations could account for why cuprates have a dome-shaped superconductivity region in the phase *** study,thus,contributes to a fundamental understanding of the correlation between doping,local magnetic order,and superconductivity of HTS.

关键词： high-temperature superconductivity antiferromagnetic order electron-phonon coupling doping effect cuprates

Water modeling on fluid flow and mixing phenomena in a BOF steelmaking converter

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Journal of Iron and Steel Research International 2024年第3期31卷 595-607页

作者： Xin-yu cai Hao-jian Duan Ding-han Li Anjun Xu Li-feng Zhang School of Metallurgical and Ecological Engineering University of Science and Technology Beijing(USTB)Beijing 100083China School of Mechanical and Materials Engineering North China University of TechnologyBeijing 100144China

A 1∶8 physical water model was constructed to investigate the fluid flow and mixing phenomena in the basic oxygen furnace(BOF)*** particle image velocimetry was employed to measure the velocity distribution of the bath and the high-speed camera was applied to capture the cavity shape in the combined blowing BOF *** mixing time for varied operating conditions was measured by the stimulus-response *** cavity depth increased with the decrease in the lance height and the increase in the top gas flow rate while the bottom blowing gas had little influence on the cavity *** minimum cavity depth was obtained under the condition of a 69.8 m^(3)/h top gas flow rate,a 287.5 mm lance height and a 0.93 m^(3)/h bottom blowing gas flow rate,which was 161.2 *** mixing time decreased as the lance height decreased and the top blowing gas flow rate *** mixing time was first decreased and then increased with the increase in the bottom gas flow *** the condition of 69.8 m^(3)/h gas flow rate of top blowing,the 287.5 mm lance height and the 0.93 m^(3)/h gas flow rate of bottom blowing,the mixing time in the converter was 48.65 *** empirical formula between the stirring power and the mixing time in the converter was calculated.

关键词： Water model Fluid flow Particle image velocimetry Mixing time BOF converter

Study on cumulative effects of biological craniocerebral trauma under repeated blast

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Theoretical & Applied Mechanics Letters 2024年第3期14卷 174-183页

作者： Xingyuan Huang Bingchen Xia Lijun Chang Zhikang Liao hui Zhao Zhihua cai Hunan Provincial Key Laboratory of Health Maintenance for Mechanical Equipment Hunan University of Science and TechnologyXiangtan 411201China School of Mechanical and Electrical Engineering Foshan UniversityFoshan 528231China Institute for Traffic Medicine PLA Army Characteristic Medical CenterChongqing 400042China

Repeated blast impacts on personnel in explosive environments can exacerbate craniocerebral *** existing studies focus on the injury effects of a single blast,lacking in-depth analysis on the injury effects and cumulative effects of repeated ***,rats were used as the experimental samples to suffer from explosion blasts with different peak air overpressures(167 kPa~482 kPa)and varying number of repeated *** cumulative effect of craniocerebral trauma was most pronounced for moderate repeated blast,showing approximately 95%increase of trauma severity with penta blast,and an approximately 85%increase of trauma severity with penta minor *** cumulative effect of craniocerebral trauma from severe,repeated blast has a smaller rate of change compared to the other two *** severity of trauma from penta blast increased by approximately 69%compared to a single *** physiological,pathological and biochemical analysis show that the degree of neurological trauma caused by repeated blasts is higher than that of single blasts,and the pathological trauma to brain tissue is more extensive and *** trauma degree remains unchanged after double blast,increases by one grade after triple or quadruple blast,and increases by two grades after penta blast.

关键词： Repeated blast Craniocerebral trauma Trauma severity grade Cumulative effects

Enhanced Temporal Correlation for Universal Lesion Detection

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Computer Modeling in Engineering & Sciences 2024年第3期138卷 3051-3063页

作者： Muwei jian Yue Jin hui Yu School of Computer Science and Technology Shandong University of Finance and EconomicsJinanChina School of Information Science and Technology Linyi UniversityLinyiChina School of Creative Technologies University of PortsmouthPortsmouthUK

Universal lesion detection(ULD)methods for computed tomography(CT)images play a vital role in the modern clinical medicine and intelligent *** is well known that single 2D CT slices lack spatial-temporal characteristics and contextual information compared to 3D CT ***,3D CT blocks necessitate significantly higher hardware resources during the learning ***,efficiently exploiting temporal correlation and spatial-temporal features of 2D CT slices is crucial for ULD *** this paper,we propose a ULD network with the enhanced temporal correlation for this purpose,named *** designed TCE module is applied to enrich the discriminate feature representation of multiple sequential CT ***,we employ multi-scale feature maps to facilitate the localization and detection of lesions in various *** experiments are conducted on the DeepLesion benchmark demonstrate that thismethod achieves 66.84%and 78.18%for FS@0.5 and FS@1.0,respectively,outperforming compared state-of-the-art methods.

关键词： Universal lesion detection computational biology medical computing deep learning enhanced temporal correlation

Combining systemic inflammatory response index and albumin fibrinogen ratio to predict early serious complications and prognosis after resectable gastric cancer

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World Journal of Gastrointestinal Oncology 2024年第3期16卷 732-749页

作者： Jing-Yao Ren Da Wang Li-hui Zhu Shuo Liu Miao Yu hui cai School of Clinical Medicine Ningxia Medical UniversityYinchuan 750000Ningxia Hui Autonomous RegionChina General Surgery Clinical Medical Center Gansu Provincial HospitalLanzhou 730000Gansu ProvinceChina Key Laboratory of Molecular Diagnostics and Precision Medicine for Surgical Oncology in Gansu Province Gansu Provincial HospitalLanzhou 730000Gansu ProvinceChina NHC Key Laboratory of Diagnosis and Therapy of Gastrointestinal Tumor Gansu Provincial HospitalLanzhou 730000Gansu ProvinceChina Medical College of jiangsu University Jiangsu UniversityZhenjiang 212013Jiangsu ProvinceChina The First Clinical Medical School Lanzhou UniversityLanzhou 730000Gansu ProvinceChina

BACKGROUND Gastric cancer has a high incidence and fatality rate,and surgery is the preferred course of ***,patient survival rates are still low,and the incidence of major postoperative complications cannot be *** systemic inflammatory response,nutritional level,and coagulation status are key factors affecting the postoperative recovery and prognosis of gastric cancer *** systemic inflammatory response index(SIRI)and the albumin fibrinogen ratio(AFR)are two valuable comprehensive indicators of the severity and prognosis of systemic inflammation in various medical *** To assess the clinical importance and prognostic significance of the SIRI scores and the AFR on early postoperative outcomes in patients undergoing radical gastric cancer *** We conducted a retrospective analysis of the clinicopathological characteristics and relevant laboratory indices of 568 gastric cancer patients from January 2018 to December *** calculated and compared two indicators of inflammation and then examined the diagnostic ability of combined SIRI and AFR values for serious early postoperative *** scored the patients and categorized them into three groups based on their SIRI and AFR *** analysis was used to compare the three groups of patients the prognostic value of various preoperative SIRI-AFR scores for 5-year overall survival(OS)and disease-free survival(DFS).RESULTS SIRI-AFR scores were an independent risk factor for prognosis[OS:P=0.004;hazards ratio(HR)=3.134;DFS:P<0.001;HR=3.543]and had the highest diagnostic power(area under the curve:0.779;95%confidence interval:0.737-0.820)for early serious complications in patients with gastric *** tumor-node-metastasis stage(P=0.001),perioperative transfusion(P=0.044),positive carcinoembryonic antigen(P=0.014)findings,and major postoperative complications(P=0.011)were factors associated with *** Preoperative SIRI and AFR values were s

关键词： Inflammation Albumin fibrinogen ratio Gastric cancer Complications Prognosis