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An Additive-Multiplicative Cox-Aalen Subdistribution Hazard Model for Competing Risks Data

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Journal of Systems Science & Complexity 2019年第6期32卷 1727-1746页

作者： LI Wanxing long Yonghong Department of Statistics School of Mathematics and Information ScienceShaanxi Normal UniversityXi'an 710119China School of Mathematics Renmin University of ChinaBeijing 100872China

This paper proposes a flexible additive-multiplicative Cox-Aalen hazard model which allows time-varying covariate effects for the subdistribution in a competing risks *** ted estimating equation approaches under an covariates-dependent adjusted weight by fitting the Cox proportional hazard model for the censoring distribution are established for inference on the model parametric and nonparametric *** addition,large number properties are presented and the finite sample behavior of the proposed estimators is evaluated through simulation studies,estimators from the proposed method perform satisfactorily on reduction of the *** authors apply our model to a competing risks data set from a tamoxifen trail for breast cancer study.

关键词： Aalen's additive model competing risks cumulative incidence function estimating equation inverse probability of censoring weight proportional hazard function time-varying effects

Multi‑level autonomous integrity monitoring method for multi‑source PNT resilient fusion navigation

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Satellite Navigation 2023年第3期4卷 210-226页

作者： Rui Chen long Zhao School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

For the integrity monitoring of a multi-source PNT(Positioning,Navigation,and Timing)resilient fusion navigation system,a theoretical framework of multi-level autonomous integrity monitoring is *** to the mode of multi-source fusion navigation,the framework adopts the top-down logic structure and establishes the navigation source fault detection model based on the multi-combination separation residual method to detect and isolate the fault source at the system level and subsystem *** isolated non-redundant navigation sources,the system level recovery verification model is *** the isolated multi-redundant navigation sources,the sensor fault detection model optimized with the dimension-expanding matrix is used to detect and isolate the fault sensors,and the isolated fault sensors are verified in ***,according to the fault detection and verification results at each level,the observed information in the fusion navigation solution is dynamically *** this basis,the integrity risk dynamic monitoring tree is established to calculate the Protection Level(PL)and evaluate the integrity of the multi-source integrated navigation *** autonomous integrity monitoring method proposed in this paper is tested using a multi-source navigation system integrated with Inertial Navigation System(INS),Global Navigation Satellite System(GNSS),long Baseline Location(LBL),and Ultra Short Baseline Location(USBL).The test results show that the proposed method can effectively isolate the fault source within 5 s,and can quickly detect multiple faulty sensors,ensuring that the positioning accuracy of the fusion navigation system is within 5 m,effectively improving the resilience and reliability of the multi-source fusion navigation system.

关键词： Autonomous integrity monitoring Fault detection and isolation Multi-source PNT resilient fusion navigation Protection level

Mathematical Model of Hydrodynamic Torque Converter and Analytic Description of Streamline

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Chinese Journal of Mechanical Engineering 2009年第1期22卷 70-77页

作者： LIU Shiping QUAN long Institute of Mechatronics Engineering Taiyuan University of Technology Taiyuan 030024 China

The mathematical model of a 3-element centripetal-turbine hydrodynamic torque converter and analytic description of fluid flow inside the hydrodynamic torque converter are investigated. A new torus coordinate system is proposed so as to quantitatively describe fluid movement inside the hydrodynamic torque converter. The particle movement inside the hydrodynamic torque converter is decomposed into meridional component movement and torus component movement, and a universal meridional streamline equation is derived. According to the relationship between the converter wheel velocity polygon and its blade angle, a torus streamline differential equation is established. The universal meridional streamline equation is approximated with square polynomials. The approximation error curve is given and the percentage error is not greater than 0.86%. Considered as a function of polar angle, the blade angle cotangent of each converter wheel varies linearly with polar angle. By using integral calculus, torus streamline equations are obtained. As a result, the problem of difficult flow description of the hydrodynamic torque converter is solved and a new analytic research system is established.

关键词： hydrodynamic torque converter toms coordinate system analytic description meridional streamline equation toms streamline equation

Invalidity of Geometrical Interpretation of F-Spin Structure of Nuclear Rotations by Otsuka’s View

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Chinese Physics Letters 1995年第6期12卷 342-343页

作者： long Guilu Department of Physics Tsinghua UniversityBeijing 100084

In Otsuka's view of nuclear rotations neutrons and protons are not rotating around a common axis,but rather around separate *** this letter,we pointed out that this invalidates the geometrical interpretation of F-spin structure of the neutron-proton interacting boson model,where the angle between the axis of symmetries of neutron ellipsoid and proton ellipsoid is used to determine whether a state is F-spin symmetric or mixed symmetric.

关键词： symmetric validity rotating

Entrance Effect on Load Capacity of Orifice Compensated Aerostatic Bearing with Feeding Pocket

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Chinese Journal of Mechanical Engineering 2010年第4期23卷 451-459页

作者： long Wei BAO Gang School of Mechatronics Engineering Harbin Institute of Technology Harbin 150001 China

The current research of the aerostatic thrust bearing mainly focuses on the porous material bearing and inherent compensated air bearing, which aims at obtaining small physical dimension and large load capacity. Although porous material bearing appears larger load capacity, materials anisotropy itself and void content distortion caused in heat-treating, and machining processes add greater complexity to internal flow transfer process. Inherent compensated air bearing has the advantages of simple structure and good stability, but its load capacity and static stiffness is not worth somewhat. In this paper, based on hydrostatic lubrication theory, finite volume method is presented for taking entrance effects into account in computing pressure distribution, load capacity and mass flow rates of circular aerostatic thrust bearings. Technical analysis, numerical simulations and laboratory demonstration tests of influence of pocket diameter and pocket depth on loading capacity of aerostatic thrust bearing are carried out on simple orifice compensated air bearings with feeding pockets. The static parameters, such as air consumption and pressure distributions, are measured as a function of supply pressure and air gap height for several different orifices and pockets size. Entrance effects are described in term of typical throttling types, and the effect of pocket diameter and pocket depth on load capacity is systematically described respectively. The proposed research results uncover the causation of throttling action of the orifice compensated air bearing with feed pocket and further develop and improve the design theory of air bearing.

关键词： aerostatic thrust bearing feeding pocket entrance effects

Characterization of condensed phase nitric acid particles formed in the gas phase

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Journal of Environmental Sciences 2011年第3期23卷 412-418页

作者： long Jia Yongfu Xu State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

The formation of nitric acid hydrates has been observed in a chamber during the dark reaction of NO2 with O3 in the presence of air. The size of condensed phase nitric acid was measured to be 40-100 nm and 20-65 nm at relative humidity （RH） ≤ 5% and RH = 67% under our experimental conditions, respectively. The nitric acid particles were collected on the glass fiber membrane and their chemical compositions were analyzed by infrared spectrum. The main components of nitric acid hydrates in particles are HNO3.3H2O and NO3-.xH2O （x≥ 4） at low RH, whereas at high RH HNO3.H2O, HNO3-2H2O, HNO3.3H2O and NO3--xH20 （x≥ 4） all exist in the condensed phase. At high RH ***2O （x ≤3） collected on the glass fiber membrane is greatly increased, while NO3-.xH2O （x ≥ 4） decreased, compared with low RH. To the best of our knowledge, this is the first time to report that condensed phase nitric acid can be generated in the gas phase at room temperature.

关键词： nitric acid particles relative humidity chamber

On-chip silicon photonic signaling and processing: a review

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Science Bulletin 2018年第19期63卷 1267-1310页

作者： Jian Wang Yun long Wuhan National Laboratory for Optoelectronics School of Optical and Electronic Information Huazhong University of Science and Technology

The arrival of the big data era has driven the rapid development of high-speed optical signaling and processing, ranging from long-haul optical communication links to short-reach data centers and highperformance computing, and even micro-/nano-scale inter-chip and intra-chip optical ***-chip photonic signaling is essential for optical data transmission, especially for chip-scale optical interconnects, while on-chip photonic processing is a critical technology for optical data manipulation or processing, especially at the network nodes to facilitate ultracompact data management with low power consumption. In this paper, we review recent research progress in on-chip photonic signaling and processing on silicon photonics platforms. Firstly, basic key devices (lasers, modulators, detectors)are introduced. Secondly, for on-chip photonic signaling, we present recent works on on-chip data transmission of advanced multi-level modulation signals using various silicon photonic integrated devices(microring, slot waveguide, hybrid plasmonic waveguide, subwavelength grating slot waveguide).Thirdly, for on-chip photonic processing, we summarize recent works on on-chip data processing of advanced multi-level modulation signals exploiting linear and nonlinear effects in different kinds of silicon photonic integrated devices (strip waveguide, directional coupler, 2D grating coupler, microring,silicon-organic hybrid slot waveguide). Various photonic processing functions are demonstrated, such as photonic switch, filtering, polarization/wavelength/mode (de)multiplexing, wavelength conversion,signal regeneration, optical logic and computing. Additionally, we also introduce extended silicon+photonics and show recent works on on-chip graphene-silicon photonic signal processing. The advances in on-chip silicon photonic signaling and processing with favorable performance pave the way to integrate complete optical communication systems on a monolithic chip and integrate silicon

关键词： Photonic integration Silicon photonics Photonic signaling Photonic processing Optical communications Optical interconnects

Single probes and resonant four-wave-mixing enabling novel correlative light electron microscopy workflow

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Light(Science & Applications) 2023年第6期12卷 933-934页

作者： long Chen Chao He Division of Structural Biology Wellcome Trust Centre for Human GeneticsUniversity of OxfordOxford OX37BNUK Department of Engineering Science University of OxfordOxford OX13PJUK

Correlative light electron microscopy prefers single probes with stable performance in both optical and electron *** researchers have shown how to harness gold nanoparticles featuring exceptional photostability and fo... 详细信息

关键词： mixing wave exceptional

DEVELOPMENT OF COUPLED 1D-2D MATHEMATICAL MODELS FOR TIDAL RIVERS

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Journal of Hydrodynamics 2004年第6期16卷 767-776页

作者： XUZu-xin YINHai-long StateKeyLaboratoryofPollutionControlandResourceReuse TongjiUniversityShanghai200092.China

Some coupled 1D-2D hydrodynamic and water quality models depicting tidalwater bodies with complex topography were presented. For the coupled models, finite element methodwas used to solve the governing equations so as to study tidal rivers with complex topography. Sincethe 1D and 2D models were coupled, the principle of model coupling was proposed to accountappropriately for the factors of water level, flow and pollutant flux and the related dynamicalbehavior was simulated. Specifically the models were used to probe quantitative pollutioncontribution of receiving water from neighboring Jiangsu and Zhejiang Provinces to the pollution inthe Huangpu River passing through Shanghai City, Numerical examples indicated that the developedcoupled 1D-2D models are applicable in tidal river network region of Shanghai.

关键词： tidal river hydrodynamic water quality coupled model Huangpu River Shanghai