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Prescribed Performance Tracking Control of Time-Delay Nonlinear Systems With Output Constraints

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IEEE/CAA Journal of Automatica Sinica 2024年第7期11卷 1557-1565页

作者： Jin-Xi Zhang Kai-Di Xu Qing-Guo wang IEEE the State Key Laboratory of Synthetical Automation for Process Industries Northeastern UniversityShenyang 110819China Institute of Artificial Intelligence and Future Networks Beijing Normal UniversityZhuhai 519087 Guangdong Key Laboratory of Artificial Intelligence and Multi-Modal Data Processing Beijing Normal University-Hong Kong Baptist University United International CollegeZhuhai 519087

The problem of prescribed performance tracking control for unknown time-delay nonlinear systems subject to output constraints is dealt with in this paper. In contrast with related works, only the most fundamental requirements, i.e., boundedness and the local Lipschitz condition, are assumed for the allowable time delays. Moreover, we focus on the case where the reference is unknown beforehand, which renders the standard prescribed performance control designs under output constraints infeasible. To conquer these challenges, a novel robust prescribed performance control approach is put forward in this ***, a reverse tuning function is skillfully constructed and automatically generates a performance envelop for the tracking error. In addition, a unified performance analysis framework based on proof by contradiction and the barrier function is established to reveal the inherent robustness of the control system against the time delays. It turns out that the system output tracks the reference with a preassigned settling time and good accuracy,without constraint violations. A comparative simulation on a two-stage chemical reactor is carried out to illustrate the above theoretical findings.

关键词： Nonlinear systems output constraints prescribed performance reference tracking time delays

All-optical driven soft crawler with complexmotion capabilities

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International Journal of Smart and Nano Materials 2024年第2期15卷 348-364页

作者： Chenchu Zhang Jin wang Linhan Zhao Renfei Chen Qiangqiang Zhao Jie Zhao Fating Liu Yucheng Bian Heng Zhang Yisen wang Chaowei wang Ying Hu Anhui Province Key Lab of Aerospace Structural Parts Forming Technology and Equipment Institute of Industry and Equipment TechnologyHefei University of TechnologyHefeiChina CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Precision Machinery and Precision InstrumentationUniversity of Science and Technology of ChinaHefeiChina GBA Branch of Aerospace Information Research Institute Chinese Academy of SciencesGuangzhouChina

The emergence of millimeter-scale soft actuators has signifi-cantly expanded the potential applications in areas such as search and rescue,drug delivery,and human assistance,due to their high *** these advancements,achieving precise control over the intricate movements of soft crawlers poses a significant *** this study,we have developed an all-optical approach that enables manipulation of propul-sive forces by simultaneously modifying the magnitude and direction of friction forces,thereby enabling complex motions of soft ***,the approach is not constrained by specific actuator shapes,and theoretically,any elongated photothermal actuator can be *** actuator was designed with an isosceles trapezoid shape,featuring a top width of 2mm,a bottom width of 4 mm,and a length of 8 *** our,manipulation approach,we showcase a proof-of-concept for complex soft robotic motions,including crawling(achieving speeds of up to 2.25 body lengths per minute),turning,avoiding obstacles,handling and trans-ferring objects approximately twice its own weight,and navi-gating narrow spaces along programmed *** results showcasethis all-optical manipulationapproach as a promising,yet unexplored tool for the precision and wireless control for the development of advanced soft actuators.

关键词： Light driven soft actuator all-optical manipulation laser manipulation

Local resistance characteristics of elbows for supercritical pressure RP-3 flowing in serpentine micro-tubes

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Propulsion and Power Research 2024年第2期13卷 245-256页

作者： Yanchen Fu Yinlong Liu Juan wang Yu wang Guoqiang Xu Jie Wen Research Institute of Aero-engine Beihang UniversityBeijing 100191China National Key Laboratory of Science and Technology on Aero-Engine Aero-thermodynamics Beihang UniversityBeijing 100191China Zhongfa Aviation Institute of Beihang University Hangzhou 310023China AECC Sichuan Gas Turbine Research Institute Chengdu 610500China AECC Hunan Aviation Powerplant Research Institute Zhuzhou 412002China School of Energy and Power Engineering Beihang UniversityBeijing 100191China

Based on the demands of compact heat exchangers and micro cooling channels applied for aviation thermal protection on aero-engines,the elbow localﬂow resistance charac-teristics for supercritical pressure aviation fuel RP-3ﬂowing in adiabatic horizontal serpentine tubes with the inner diameter of 1.8 mm and the massﬂux of 1179 kg/(m^(2)·s)were experimen-tally *** long-short-tube method was used to obtain the elbow pressure drop from the total serpentine tube pressure drop,and the effects of system pressures(P/Pc=1.72-2.58)and geometry parameters including bend numbers(n=5-11),bend diameters(D/d=16.7-27.8),and bend distances(L/d=20-60)on elbow pressure drops and local resistance co-efﬁcients are analyzed on the basis of the thermal physical property *** results show that both the increase in the elbow pressure drop and the decrease in the local resistance coef-ﬁcient with temperatures speed up at the near pseudo-critical temperature region of T>*** the growth of the elbow local pressure drop could be inhibited by the increase of system pressures,while the local resistance coefﬁcient is slightly affected by *** inﬂuence of bend diameters on the local resistance coefﬁcient is mild when D/d is larger than 22.2 in the premise of fully developedﬂow in straight ***,a piecewise empir-ical correlation considering the bend diameter and physical property ratio is developed to pre-dict the elbow pressure drop of the serpentine tube and optimize the layout of the cooling tube system on aero-engines.

关键词： Supercritical pressure Aviation fuel Local resistance coefﬁcient Elbow Serpentine tube Empirical correlation

Efficacy and safety of Huzhang Granule,a compound Chinese herbal medicine,for acute gouty arthritis:A double-blind,randomized controlled trial

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Journal of Integrative Medicine 2024年第3期22卷 270-278页

作者： Hao wang Si-ting Chen Xiao-jie Ding Le Kuai Liang Hua Xin Li Yi-fei wang Ming Zhang Bin Li Rui-ping wang Mi Zhou Department of Dermatology Yueyang Hospital of Integrated Traditional Chinese and Western MedicineShanghai University of Traditional Chinese MedicineShanghai 200437China Institute of Dermatology Shanghai Academy of Traditional Chinese MedicineShanghai 201203China Department of Dermatology the Affiliated Hospital of Jiangxi University of Chinese MedicineNanchang 330000Jiangxi ProvinceChina Shanghai Skin Disease Hospital School of MedicineTongji UniversityShanghai 200443China Institute of Dermatology School of MedicineTongji UniversityShanghai 200443China

Background:Acute gouty arthritis(AGA)is an inflammatory joint disease with a high *** medical interventions,including nonsteroidal anti-inflammatory drugs,colchicine and glucocorticoids,can have serious adverse *** Granule(HZG),a compound Chinese herbal medicine,has been used to treat AGA for more than 30 years with satisfactory effects and no significant adverse ***,the efficacy and safety of HZG in AGA patients remains ***:The present investigation was designed to examine the efficacy and safety profile of HZG in managing AGA ***,setting,participants and interventions:The current study was conducted as a noninferiority,randomized controlled clinical trial on 180 eligible enrolled *** were randomly assigned into the HZG and etoricoxib *** were administered for 5 d,during which the HZG group received HZG and placebo etoricoxib,while the etoricoxib group received etoricoxib and placebo HZG in the same ratio(1:1).Main outcome measures:The primary outcome was pain experienced by the patient in the gout-afflicted joint from days 2 to 5 of the treatment *** pain level was measured via a visual analogue scale,ranging from 0 mm to 100 *** secondary outcomes comprised joint tenderness and swelling,reduction of inflammatory biomarkers,and the patient’s and investigator’s global evaluations of therapeutic ***:The mean reduction in pain was-51.22 mm(95%confidence interval[CI],[-53.42,-49.03]mm)for the HZG and-52.00 mm(95%CI,[-54.06,-49.94]mm)for the etoricoxib *** mean difference between the two groups was 0.78 mm(95%CI,[-2.25,3.81]mm).All additional efficacy endpoints,covering decreased inflammation and pain relief,yielded compelling proof of *** in the HZG group exhibited a comparatively lower rate of adverse events compared to those in the etoricoxib group(4.44%vs 13.33%;P≤0.05).Conclusion:HZG and etoricoxib groups demons

关键词： Acute gouty arthritis Huzhang Granule Randomized controlled trial Blind

Advancing insights into in vivo meningeal lymphatic vessels with stereoscopic wide-field photoacoustic microscopy

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Light(Science & Applications) 2024年第5期13卷 894-907页

作者： Fei Yang Zhiyang wang Wenbin Shi Miao wang Rui Ma Wuyu Zhang Xipeng Li Erqi wang Wenjie Xie Zhan Zhang Qi Shen Feifan Zhou Sihua Yang MOE Key Laboratory of Laser Life Science&Institute of Laser Life Science South China Normal UniversityGuangzhou 510631China. Guangdong Provincial Key Laboratory of Laser Life Science College of BiophotonicsSouth China Normal UniversityGuangzhou 510631China. Key Laboratory of Biomedical Engineering of Hainan Province School of Biomedical EngineeringHainan UniversityHaikou 570100China. Department of Neurology Sun Yatsen Memorial HospitalSun Yat-sen UniversityGuangzhou 510120China. Guangdong Province Key Laboratory of Brain Function and Disease Zhongshan School of MedicineSun Yat-sen UniversityGuangzhou 510120China. Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter South China Normal UniversityGuangzhou 510006China

Meningeal lymphatic vessels(mLVs)play a pivotal role in regulating metabolic waste from cerebrospinal fluid(CSF).However,the current limitations in field of view and resolution of existing imaging techniques impede understanding the stereoscopic morphology and dynamic behavior of mLVs in ***,we utilized dual-contrast functional photoacoustic microscopy to achieve wide-field intravital imaging of the lymphatic system,including mLVs and glymphatic *** stereoscopic photoacoustic microscopy based on opto-acoustic confocal features has a depth imaging capability of 3.75 mm,facilitating differentiation between mLVs on the meninges and glymphatic pathways within the brain ***,using this imaging technique,we were able to visualize the dynamic drainage of mLVs and identify a peak drainage period occurring around 20–40 min after injection,along with determining the flow direction from CSF to lymph ***,in the Alzheimer’s disease(AD)mouse model,we observed that AD mice exhibit a~70%reduction in drainage volume of mLVs compared to wild-type *** the development of AD,there is be continued decline in mLVs drainage *** finding clearly demonstrates that the AD mouse model has impaired CSF *** study opens up a horizon for understanding the brain’s drainage mechanism and dissecting mLVs-associated neurological disorders.

关键词： lymphatic impaired field

Role of heterogenous microstructure and deformation behavior in achieving superior strength-ductility synergy in zinc fabricated via laser powder bed fusion

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International Journal of Extreme Manufacturing 2024年第4期6卷 225-245页

作者： Zhi Dong Changjun Han Yanzhe Zhao Jinmiao Huang Chenrong Ling Gaoling Hu Yunhui wang Di wang Changhui Song Yongqiang Yang School of Mechanical and Automotive Engineering South China University of TechnologyGuangzhou 510641People's Republic of China

Zinc(Zn)is considered a promising biodegradable metal for implant applications due to its appropriate degradability and favorable osteogenesis *** this work,laser powder bed fusion(LPBF)additive manufacturing was employed to fabricate pure Zn with a heterogeneous microstructure and exceptional strength-ductility *** optimized processing window of LPBF was established for printing Zn samples with relative densities greater than 99%using a laser power range of 80∼90 W and a scanning speed of 900 mm s−*** Zn sample printed with a power of 80 W at a speed of 900 mm s−1 exhibited a hierarchical heterogeneous microstructure consisting of millimeter-scale molten pool boundaries,micrometer-scale bimodal grains,and nanometer-scale pre-existing dislocations,due to rapid cooling rates and significant thermal gradients formed in the molten *** printed sample exhibited the highest ductility of∼12.1%among all reported LPBF-printed pure Zn to date with appreciable ultimate tensile strength(∼128.7 MPa).Such superior strength-ductility synergy can be attributed to the presence of multiple deformation mechanisms that are primarily governed by heterogeneous deformation-induced hardening resulting from the alternative arrangement of bimodal Zn grains with pre-existing ***,continuous strain hardening was facilitated through the interactions between deformation twins,grains and dislocations as strain accumulated,further contributing to the superior strength-ductility *** findings provide valuable insights into the deformation behavior and mechanisms underlying exceptional mechanical properties of LPBF-printed Zn and its alloys for implant applications.

关键词： laser powder bed fusion zinc heterogeneous microstructure bimodal grains strength-ductility synergy

Mechanism of high-energy pulsed current-assisted rolling of 08AL carbon steel ultra-thin strip

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Journal of Iron and Steel Research International 2024年第2期31卷 416-427页

作者： Zhong-kai Ren Ya-nan Xu Jia-zhao Chen He Li Rui-lin Yuan Zhen-hua wang Tao wang Xiao Liu College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan030024ShanxiChina Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment(Ministry of Education) Taiyuan University of TechnologyTaiyuan030024ShanxiChina National Key Laboratory of Metal Forming Technology and Heavy Equipment China National Heavy Machinery Research Institute Co.Ltd.Xi’an710016ShaanxiChina

To improve the plastic deformation performance of a 08AL carbon steel ultra-thin strip,a pulsed electric field was integrated into the plastic processing of the ultra-thin strip,and the effects of high-energy current on its deformation ability were ***-assisted tensile tests were employed,and the results clarified that the pulsed current could reduce the activation energy of faults and promoted dislocation slip within grains and at grain boundaries,leading to a decrease in the deformation resistance of the metal and an increase in its plastic *** the current density of 2.0 A/mm2,the yield strength,tensile strength,and elongation of the rolled sample reached 425 MPa,467 MPa,and 12.5%,*** the rolling process,it was found that the pulsed current promoted the dynamic recrystallization of the ultra-thin strip,reduced its dislocation density and deformation resistance,and promoted the coordinated deformation of the metal.

关键词： 08AL ultra-thin strip High-energy pulsed current Mechanical property Dislocation density Dynamic recrystallization

Kinematic deformation and intensity assessment of the 2021 Maduo M_(S)7.4 earthquake in Qinghai revealed by high-frequency GNSS

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Geodesy and Geodynamics 2024年第3期15卷 230-240页

作者： Yu Li Yuebing wang Lijiang Zhao Hongbo Shi Pingping wang Institute of Geophysics China Earthquake AdministrationBeijing 100081China China Earthquake Networks Center China Earthquake AdministrationBeijing 100045China Qinghai Institute of Geological Surveying and Mapping Geographic Information Qinghai 810001China Beijing Sixents Technology Co. Ltd.Beijing 100094China

Rapid acquisition of the kinematic deformation field and seismic intensity distribution of large earthquakes is crucial for postseismic emergency rescue,disaster assessment,and future seismic risk *** advancement of GNSS observation and data processing makes it play an important role in this field,especially the high-frequency *** used the differential positioning method to calculate the 1 HZ GNSS data from 98 sites within 1000 km of the M_(S)7.4 Maduo earthquake *** kinematic deformation field and the distribution of the seismic intensity by using the peak ground velocity derived from displacement waveforms were *** results show that:1)Horizontal coseismic response deformation levels ranging from 25 mm to 301 mm can be observed within a 1000 km radius from the *** response deformation on the east and west sides shows bilateral asymmetry,which markedly differs from the symmetry presented by surface rupture.2)The seismic intensity obtained through high-frequency GNSS and field investigations exhibits good consistency of the scope and orientation in the high seismic intensity area,although the former is generally slightly smaller than the latter.3)There may exist obstacles on the eastern side of the seismogenic *** Maduo earthquake induced a certain tectonic stress loading effect on the western Kunlun Pass-Jiangcuo fault(KPJF)and Maqin-Maqu segment,resulting in higher seismic risk in the future.

关键词： Maduo earthquake High-frequency GNSS Kinematic deformation Seismic intensity

A Fast Startup Crystal Oscillator with Digital SAR-AFC Based Two-Step Injection

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Chinese Journal of Electronics 2024年第5期33卷 1147-1153页

作者： Bo ZHOU Yifan LI Zuhang wang School of Integrated Circuits and Electronics Beijing Institute of Technology

Crystal oscillators（XOs） provide a high-precision reference frequency but have a long startup time,which severely increases the average power consumption in duty-cycled *** paper proposes a fully-digital low-cost two-step injection technique,by using a successive approximation register（SAR） based auto frequency control（AFC） loop,to speed up the startup behavior of XOs.A theoretical analysis is carried out to determine the optimum injection time and design low-power *** in a 65 nm CMOS process,the proposed 12 MHz fast startup XO occupies an active area of 0.02 mm2and achieves a startup time less than 35 μ*** XO power consumption in the steady state is 40 μW from a 1.0-V supply,with a startup energy of 17.2 nJ.

关键词： Time-frequency analysis Power demand Power measurement Crystals Time measurement Steady-state Registers Crystal oscillator Two-step injection Successive approximation register Auto frequency control Fully-digital Fast startup ENERGY