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Effects of layer interactions on instantaneous stability of finite Stokes flows

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 69-84页

作者： chen zhao Zhenli cHEN c.T.MUTASA Dong LI School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China

The stability analysis of a finite Stokes layer is of practical importance in flow control. In the present work, the instantaneous stability of a finite Stokes layer with layer interactions is studied via a linear stability analysis of the frozen phases of the base flow. The oscillations of two plates can have different velocity amplitudes, initial phases, and frequencies. The effects of the Stokes-layer interactions on the stability when two plates oscillate synchronously are analyzed. The growth rates of two most unstable modes when δ ckness and the half height of the channel, respectively. However, their vorticities are different. The vorticity of the most unstable mode is symmetric, while the other is asymmetric. The Stokes-layer interactions have a destabilizing effect on the most unstable mode when δ ct when δ > 0.68. However, the interactions always have a stabilizing effect on the other unstable mode. It is explained that one of the two unstable modes has much higher dissipation than the other one when the Stokes-layer interactions are strong. We also find that the stability of the Stokes layer is closely related to the inflectional points of the base-flow velocity profile. The effects of inconsistent velocity-amplitude, initial phase, and frequency of the oscillations on the stability are analyzed. The energy of the most unstable eigenvector is mainly distributed near the plate of higher velocity amplitude or higher oscillation frequency. The effects of the initial phase difference are complicated because the base-flow velocity is extremely sensitive to the initial phase.

关键词： finite Stokes layer instantaneous stability Stokes-layer interaction asynchronous oscillation

Data-driven Static Equivalence with Physics-informed Koopman Operators

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cSEE Journal of Power and Energy Systems 2024年第1期10卷 432-438页

作者： Wei Lin changhong zhao Maosheng Gao c.Y.chung Department of Electrical Engineering The Hong Kong Polytechnic UniversityHong Kong SARChina Department of Information Engineering The Chinese University of Hong KongHong Kong SARChina School of Electrical Engineering Chongqing UniversityChongqing 400044China

With deployment of measurement units,fitting static equivalent models of distribution networks(DNs)by linear regression has been recognized as an effective method in power flow analysis of a transmission *** volatility of measurements caused by variable distributed renewable energy sources makes it more difficult to accurately fit such equivalent *** tackle this challenge,this letter proposes a novel data-driven method to improve equivalency accuracy of DNs with distributed energy *** letter provides a new perspective that an equivalent model can be regarded as a mapping from internal conditions and border voltages to border power *** mapping can be established through 1)Koopman operator theory,and 2)physical features of power flow equations at the root node of a *** of the proposed method is demonstrated on the IEEE 33-bus and IEEE 136-bus test systems connected to a 661-bus utility system.

关键词： Data-driven distribution network Koopman operator theory static equivalent model

Adaptive neural network control of a 2-DOF helicopter system considering input constraints and global prescribed performance

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Science china(Information Sciences) 2024年第7期67卷 224-239页

作者： Zhijia zhao Jiale WU Zhijie LIU We HE c.L.Philip cHEN School of Mechanical and Electrical Engineering Guangzhou University School of Intelligence Science and Technology and Key Laboratory of Intelligent Bionic Unmanned Systems of Ministry of Education University of Science and Technology Beijing School of computer Science and Engineering South China University of Technology Pazhou Lab

In this study, an adaptive neural network(NN) control is proposed for nonlinear two-degree-offreedom(2-DOF) helicopter systems considering the input constraints and global prescribed ***, radial basis function NN(RBFNN) is employed to estimate the unknown dynamics of the helicopter system. Second, a smooth nonaffine function is exploited to approximate and address nonlinear constraint functions. Subsequently, a new prescribed function is proposed, and an original constrained error is transformed into an equivalent unconstrained error using the error transformation and barrier function transformation methods. The analysis of the established Lyapunov function proves that the controlled system is globally uniformly bounded. Finally, the simulation and experimental results on a constructed Quanser's test platform verify the rationality and feasibility of the proposed control.

关键词： adaptive NN control 2-DOF helicopter global prescribed performance input constraints

Spatial distributions of soil nutrients affected by land use,topography and their interactions,in the Loess Plateau of china

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International Soil and Water conservation Research 2024年第1期12卷 227-239页

作者： Wenxin Zhou changjia Li Wenwu zhao Lindsay c.Stringer Bojie Fu State Key Laboratory of Earth Surface Processes and Resource Ecology Faculty of Geographical ScienceBeijing Normal UniversityBeijingChina Institute of Land Surface System and Sustainable Development Faculty of Geographical ScienceBeijing Normal UniversityBeijingChina Department of Environment and Geography University of YorkYorkUK York Environmental Sustainability Institute University of YorkYorkUK

Soil nutrient availability and their spatial distributions are strongly related to land use and landscape *** study aims to address the knowledge gap regarding the interaction between these factors and the underlying *** selected five land uses(grassland with Artemisia gmelinii,woodland with Robinia pseudoacacia,shrubland with caragana korshinskii and Hippophae rhamnoides,and apple orchard with Malus pumila)and nine slope positions across hillslopes in the Loess Plateau,china,to investigate their combined effects on the contents and stocks of soil organic carbon(SOc),total nitrogen(TN)and total phosphorus(TP).Parametric and non-parametric statistical tests were conducted to determine the significant differences in the means or the medians of the soil nutrient *** showed that the SOc and TN contents of shrubland with caragana korshinskii were statistically significantly greater than those of the grassland(pc and TN contents generally decreased from the upper slope to the middle slope,and to the foot slope for the grassland,woodland and shrublands,and on the contrary,an increasing trend from the upper slope,to the middle slope,and to the foot slope was identified for the apple *** study highlights that land use,slope position and their interaction have significant effects on the spatial distributions of soil *** provides essential empirical evidence for the identification of the optimal vegetation type and slope positions in land management and vegetation restoration activities.

关键词： Soil organic carbon Total nitrogen Total phosphorus Slope position Vegetation restoration

One dimensional ceO_(2) nanorods/poly(ethylene oxide) solid composite electrolyte for all-solid-state lithium-ion batteries

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Journal of Rare Earths 2024年第3期42卷 570-577,I0005页

作者： Yudi Guo Erqing zhao Xiaofang zhao Shuailei Liu School of chemistry and Materials Engineering Xinxiang UniversityXinxiang453003China School of chemistry and chemical Engineering Henan Institute of Science and TechnologyXinxiang453003China

The research of poly(ethylene oxide)(PEO)-based solid composite electrolyte with high ionic conductivity and excellent interfacial stability is the key to the development of all-solid-state lithium-ion batteries(ASSLIBs). Herein, uniform nanorod structured ceO_(2) fillers were controllably synthesized by electrospinning, which were subsequently filled into PEO polymer to prepare ceO_(2)/PEO solid composite electrolyte. The addition of ceO_(2) nanorods can reduce both the glass transition temperature and the melting point of PEO polymer, and also interact with PEO and lithium bis(trifluoromethanesulphonyl)imide(LITFSI) by Lewis acid—base reaction. Therefore, the solid composite electrolyte exhibits a high ionic conductivity of 4.52 × 10^(-4)S/cm, a wide electrochemical stability window of about 4.8 V, and a good interfacial stability with Li at 55℃. Moreover, the LiFePO_4/Li ASSLIB divulges the discharging specific capacity of 165, 162, 156 and 146 mA,h/g at 0.2, 0.5, 1 and 2 c, respectively, and achieves the capacity retention of 90.3% after 150 cycles at 0.5 c. consequently, one dimensional ceO_(2) nanorods can be considered as an alternative filler for polymeric solid electrolyte.

关键词： Poly(ethylene oxide) Solid composite electrolyte ceO_(2)nanorods Ionic conductivity Rare earths

Summarizing the evidence for robotic-assisted bladder neck reconstruction: Systematic review of patency and incontinence outcomes

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Asian Journal of Urology 2024年第3期11卷 341-347页

作者： Tenny R.Zhang Ashley Alford Lee c.zhao Department of Urology NewYork-Presbyterian Hospital/Weill Cornell MedicineNew YorkNYUSA Department of Urology NYU Langone Medical CenterNew YorkNYUSA

Objective:Bladder neck contracture and vesicourethral anastomotic stenosis are difficult to manage endoscopically,and open repair is associated with high rates of *** recent years,there have been increasing reports of robotic-assisted bladder neck reconstruction in the ***,existing studies are small,heterogeneous case *** objective of this study was to perform a systematic review of robotic-assisted bladder neck reconstruction to better evaluate patency and incontinence ***:We performed a systematic review of PubMed from first available date to May 2023 for all studies evaluating robotic-assisted reconstructive surgery of the bladder neck in adult *** in non-English,author replies,editorials,pediatric-based studies,and reviews were *** of interest were patency and incontinence rates,which were pooled when ***:After identifying 158 articles on initial search,we included only ten studies that fit all aforementioned criteria for robotic-assisted bladder neck *** were case series published from March 2018 to March 2022 ranging from six to 32 men,with the median follow-up of 5e23 months.A total of 119 patients were included in our analysis.A variety of etiologies and surgical techniques were *** rates ranged from 50%to 100%,and pooled patency was 80%(95/119).De novo incontinence rates ranged from 0%to 33%,and pooled incontinence was 17%(8/47).Our findings were limited by small sample sizes,relatively short follow-ups,and heterogeneity between studies.

关键词： Bladder neck continence Incontinence Patency Posterior urethra Reconstructive surgery Robotic surgery Stenosis Stricture Surgical outcome

Effects of lighting conditions and accommodation on the three-dimensional position of Visian implantable collamer lens

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Eye and Vision 2024年第3期10卷 31-40页

作者： Lingling Niu Zhe Zhang Huamao Miao Jing zhao Xiaoying Wang Ji c.He Xingtao Zhou Department of Ophthalmology and Optometry Eye&ENT HospitalFudan UniversityShanghaiChina NHc Key Laboratory of Myopia(Fudan University) ShanghaiChina Key Laboratory of Myopia Chinese Academy of Medical SciencesShanghaiChina Shanghai Research center of Ophthalmology and Optometry ShanghaiChina New England college of Optometry MABostonUSA

Background To investigate the effects of lighting conditions and accommodation on the three-dimensional position of Visian implantable collamer lens(IcL V4c).Methods This observational study recruited 62 eyes of 31 myopia patients underwent IcL V4c *** segment optical coherence tomography(AS-OcT)assessed the anterior chamber depth(AcD),AcD-IcL(distance from the corneal endothelium to anterior surface of the IcL V4c),vault(distance between the posterior IcL V4c surface and anterior crystalline lens surface),and crystalline lens tilt under various lighting conditions and accommodation relative to the corneal topographic axis at one year after IcL V4c *** was defined as the scotopic condition,which was also the non-accommodative stimulus *** IcL V4c tilt was analyzed using *** significance level was set at PcD-IcL values were similar under various lighting conditions(P=0.978)but decreased during accommodation(Pcantly smaller under mesopic and photopic conditions than the baseline(P=0.044 and Pctively)but remained unchanged during accommodation(P=0.058).The inferotemporal proportion of IcL V4c(88.7%,55 eyes)and crystalline lens(74.2%,46 eyes)tilts were not significantly different(P=0.063).crystalline lens under various lighting conditions and accommodation exhibited similar *** vertical tilt of IcL V4c was significantly larger under photopic conditions than the baseline(P=0.038).The horizontal and total tilts were significantly decreased during accommodation(P=0.043 and 0.013,respectively).conclusions The axial position of IcL V4c in the anterior chamber was stable under various lighting *** conditions and accommodation may influence vertical,horizontal and total tilts of IcL V4c.

关键词： Implantable collamer lens Anterior segment optical coherence tomography Myopia Tilt

From Liquid to Solid‑State Lithium Metal Batteries:Fundamental Issues and Recent Developments

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Nano-Micro Letters 2024年第2期16卷 68-125页

作者： zhao Zhang Wei‑Qiang Han School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027People’s Republic of China

The widespread adoption of lithium-ion batteries has been driven by the proliferation of portable electronic devices and electric vehicles,which have increasingly stringent energy density *** metal batteries(LMBs),with their ultralow reduction potential and high theoretical capacity,are widely regarded as the most promising technical pathway for achieving high energy density *** this review,we provide a comprehensive overview of fundamental issues related to high reactivity and migrated interfaces in ***,we propose improved strategies involving interface engineering,3D current collector design,electrolyte optimization,separator modification,application of alloyed anodes,and external field regulation to address these *** utilization of solid-state electrolytes can significantly enhance the safety of LMBs and represents the only viable approach for advancing *** review also encompasses the variation in fundamental issues and design strategies for the transition from liquid to solid *** noteworthy is that the introduction of SSEs will exacerbate differences in electrochemical and mechanical properties at the interface,leading to increased interface inhomogeneity—a critical factor contributing to failure in all-solidstate lithium metal *** on recent research works,this perspective highlights the current status of research on developing high-performance LMBs.

关键词： Lithium metal batteries All-solid-state lithium metal battery Li dendrite Solid electrolyte Interface

Remarkable enhancement of gas selectivity on organosilica hybrid membranes using urea-modulated metal-organic framework nanoparticles

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Frontiers of chemical Science and Engineering 2024年第2期18卷 83-92页

作者： Yayun zhao Dechuan zhao chunlong Kong Yichao Lin Xuezhen Wang Liang chen Key Laboratory of Advanced Fuel cells and Electrolyzers Technology of Zhejiang Province Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China University of chinese Academy of Sciences Beijing 100049China collaboration Innovation center for Tissue Repair Material Engineering Technology China West Normal UniversityNanchong 637009China

Metal-organic framework/organosilica hybrid membranes on tubular ceramic substrates have shown great potential for the implementation of membrane technology in practical gas separation projects due to their higher permeance compared to commercial ***,the selectivities of the reported membranes are ***,we have incorporated urea-modulated metal-organic frameworks into organosilica membranes to greatly enhance its separation *** urea-modulated metal-organic frameworks exhibit less-defined edges of crystallographic facets and high defect *** can be well-dispersed in the organosilica layer,which substantially suppresses the interfacial defects between metal-organic frameworks and organosilica,which is beneficial for improving the selectivity of membranes for gas *** results have shown that the enhanced ideal selectivity of H_(2)/cH_(4) was 165 and that of cO_(2)/cH_(4) was 43,with H_(2) permeance of about 1.25×10^(−6) mol·m^(−2)·s^(−1)·Pa^(−1) and cO_(2) permeance of 3.27×10^(−7) mol·m^(−2)·s^(−1)·Pa^(−1) at 0.2 MPa and 25℃.In conclusion,the high level of hybrid membranes can be used to separate H_(2)(or cO_(2))from the binary gas mixture H_(2)/cH_(4)(or cO_(2)/cH_(4)),which is important for gas separation in practical ***,the simple and feasible modulation of metal-organic framework is a promising strategy to tune different metal-organic frameworks for membranes according to the actual demands.

关键词： ZIF-8 nanocrystals urea organosilica hybrid membrane enhanced separation performance