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Correlation analysis between fault frequency and service time of underground fluid instruments

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Geodesy and Geodynamics 2023年第4期14卷 411-418页

作者： xiao tian Guoying Su The First Monitoring and Application Center China Earthquake AdministrationTianjin 300180China

In this paper, we make a statistical analysis of the fault information of the underground fluid instruments of 12 models in China from January 2021 to May 2022 based on the Pearson correlation coefficient, and compare the fault statistics of the meteorological three-element instruments of 3 models during the study period. The results show that:(1) The numbers of faults of the underground fluid instruments of 12models with different service times are basically positively correlated with the numbers of the corresponding instruments, with good consistency. Moreover, the automatic observation instruments(8models) with more than 30 units are significantly correlated at a 0.05 significance level(95% confidence level). Even at a 0.01 significance level(99% confidence level), there are 7 models(7/8) with significant correlation.(2) The positive and negative correlations between the monthly average number of faults and the corresponding service times of the underground fluid instruments of 12 models with different service times are random, and there are 9 models(75%) with no significant correlation at a 0.05 significance level(95% confidence level), while 12 models(100%) with no significant correlation at a 0.01significance level(99% confidence level).(3) The monthly average numbers of faults of the underground fluid instruments of 12 models are basically 0.02-0.05 times/(unit·month), and the overall fault frequency is low.(4) The fault statistics results of the meteorological three-element instruments of 3 models are consistent with the characteristics of the underground fluid instruments of 12 models. In general,there is no significant correlation between the fault frequency and the service time of underground fluid instruments.(5) The results of this paper demonstrate that the service time of underground fluid instruments cannot be taken as the main reason for whether to update the instruments. Similarly, the fault frequency of the instruments cannot be taken as the main

关键词： Underground fluid instruments Fault frequency Service time Correlation analysis

Two 3-D multi-cascade co-design inverse methods based on streamline curvature approach and Clebsch formulation for single-stage centrifugal compressors

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航空动力学报 2013年第7期28卷 1526-1538页

作者： tian xiao-pei SHAN Peng School of Energy and Power Engineering Beijing University of Aeronautics and Astronautics

Two strategies extended the single-cascade methods from a compressible three-dimensional inverse method for radial and mixed flow turbomachines to two three-dimensional multi-cascade co-design methods for single-stage centrifugal *** two three-dimensional methods and a typical quasi-threedimensional streamline curvature through-flow inverse method were employed to design the same subsonic high-speed single-stage centrifugal *** compressor performances were simulated by a commercial Reynolds averaged Navier-Stokes(RANS) equations *** studies show that two three-dimensional codesign methods are reasonable and *** was found that : firstly the blade camber angle designed by the three-dimensional methods was larger than that designed by the quasi-three-dimensional method;and secondly with regard to two three-dimensional methods with different boundary conditions,the co-design result differences between the diffusers were small,but those between the deswirlers were relatively large.

关键词： centrifugal compressor through-flow inverse method three-dimensional inverse problem streamline curvature approach Clebsch formulation multi-cascade co-design

Dependence of Amorphous Formation Ability on Intrinsic Parameters in Dy-Gd-Co-Al Alloys

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Journal of Materials Science & Technology 2009年第5期25卷 665-668页

作者： Lin Luo Rui tian Xueshan xiao Institute of Materials Shanghai University Shanghai 200072 China

A series of Dy（Gd）-based bulk amorphous alloy rods were prepared by water-cooled copper mold method. Thermal stability and structure of Dy-Gd-Co-Al alloys were investigated by differential scanning calorimetry and X-ray diffraction, respectively. The results show that the Dy-Gd-Co-Al alloys have good glass-formation ability, and the Dy31Gd25Co20Al24 alloy can be readily cast into full glassy rods up to 5 mm in diameter. The glass-forming ability of multicomponent alloys was greatly dependent on their chemical interaction and the equivalent bond parameters among atoms such as equivalent electronegativity difference, equivalent atomic size parameter. The Dy （Gd）-based bulk amorphous alloys could be expected as potential functional materials.

关键词： Dy(Gd)-based Glass forming ability Intrinsic parameters

Asymptotic inference for AR(1) panel data

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Applied Mathematics(A Journal of Chinese Universities) 2020年第3期35卷 265-280页

作者： SHEN Jian-fei PANG tian-xiao School of Mathematical Sciences Zhejiang UniversityHangzhou 310027China

A general asymptotic theory is given for the panel data AR(1) model with time series independent in different cross sections. The theory covers the cases of stationary process, local to unity process, unit root process, mildly integrated, mildly explosive and explosive processes. It is assumed that the cross-sectional dimension and time-series dimension are respectively N and T. The results in this paper illustrate that whichever the process is, with an appropriate regularization, the least squares estimator of the autoregressive coefficient converges in distribution to a normal distribution with rate at least O(N-1/3). Since the variance is the key to characterize the normal distribution, it is important to discuss the variance of the least squares estimator. We will show that when the autoregressive coefficient ρ satisfies |ρ| 1. ρ = 1 is the critical point where the convergence rate changes radically. The transition process is studied by assuming ρ depending on T and going to 1. An interesting phenomenon discovered in this paper is that, in the explosive case, the least squares estimator of the autoregressive coefficient has a standard normal limiting distribution in the panel data case while it may not has a limiting distribution in the univariate time series case.

关键词： AR(1)model Least squares estimator Limiting distribution Non-stationray Panel data

On Characterization of Poisson Integrals of Schr?dinger Operators with Morrey Traces

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Acta Mathematica Sinica,English Series 2018年第4期34卷 787-800页

作者： Liang SONG xiao xiao tian Li Xin YAN Department of Mathematics Sun Yat-sen University

Let L be a Schrodinger operator of the form L = -△ ＋ V acting on L2（Rn） where the nonnegative potential V belongs to the reverse Holder class Bq for some q _〉 n. In this article we will show that a function f∈ L2,λ（Rn）, 0 〈λ 〈 n, is the trace of the solution of Lu = -utt ＋ Lu = O, u（x, 0） = f（x）, where u satisfies a Carleson type condition sup t-λB xB,rB∫τB 0∫B（xB,τB）t{ u（x,t）}2dxdt≤C〈∞.Its proof heavily relies on investigate the intrinsic relationship between the classical Morrey spaces and the new Campanato spaces .L2,λL（Rn） associated to the operator L, i.e. Conversely, this Carleson type condition characterizes all the L-harmonic functions whose traces belong to the space L2,λ（Rn） for all 0 〈λ〈 n.

关键词： SchrSdinger operators Dirichlet problem Morrey spaces Campanato spaces Poissonsemigroup

One-dimensional Intrinsic Ferromagnetic Semiconductor CuCl2: a First-principles Study

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Chinese Journal of Structural Chemistry 2019年第9期38卷 1432-1440页

作者： xiao tian-tian WANG Guo LIAO Yi Department of Chemistry Capital Normal University

One-dimensional nanowires with robust magnetism are desirable for spintronic applications. Herein, on the basis of the first-principles calculations, systematic investigations on the electronic and magnetic properties of the CuCl2 nanowire were performed, which can be potentially tailored from its bulk form. The CuCl2 nanowire exhibits a ferromagnetic ground state. The band structures indicate that the CuCl2 nanowire is a ferromagnetic semiconductor. The spin flip gap is large enough for avoiding spin flip. Phonon dispersion and Born-Oppenheimer molecular dynamics simulation manifest that the CuCl2 nanowire is stable. In addition, distinct magnetic properties of the CuCl2 nanowires inside two types of carbon nanotubes were obtained. The study broadens the family of the existing one-dimensional materials with promising applications for spintronics.

关键词： CuCl2 one-dimensional ferromagnetic

A Facile Synthesis of Squamosamide Cyclic Analogs

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Chinese Chemical Letters 2003年第7期14卷 667-669页

作者： xiao Zhen JIAO Ping XIE xiao tian LIANG Institute of Materia Medica Chinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100050

A series of novel cyclic derivatives have been synthesized by utilizing a nickel powder mediated radical cyclization as the key step. The structures of the new compounds were confirmed by 1H-NMR and MS.

关键词： Squamosamide radical cyclization synthesis.

Quenching autofluorescence in the alimentary canal tissues of Bactericera cockerelli(Hemiptera:Triozidae)for immunofluorescence labeling

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Insect Science 2020年第3期27卷 475-486页

作者： xiao-tian Tang Freddy Ibanez Cecilia Tamborindeguy Department of Entomology Texas A&M UniversityCollege StationTexasUSA

Immunofluorescence has been widely used to localize microbes or specific molecules in insect tissues or ***,significant autofluorescence is frequently observed in tissues which can interfere with the fluorescent identification of target antigens,leading to inaccurate or even false positive fluorescent *** alimentary canal of the potato psyllid,Bactericera cockerelliŠulc,exhibits intense autofluorescence,hindering the application of immunolocalization for the detection and localization of the economically important pathogen transmitted by this insect,“Candidatus Liberibacter solanacearum”(Lso).In the present study,we tested the use of irradiation,hydrogen peroxide(H2O2)and Sudan black B(SBB)treatments to reduce the autofluorescence in the *** alimentary canal ***,we assessed the compatibility of the above‐mentioned treatments with Lso immunolocalization and actin staining using *** results showed that the autofluorescence in the alimentary canal was reduced by irradiation,H2O2,or SBB *** compatibility assays indicated that irradiation and H2O2 treatment both greatly reduced the fluorescent signal associated with Lso and ***,the SBB incubation preserved those target signals,while efficiently eliminating autofluorescence in the psyllid alimentary ***,herein we propose a robust method for reducing the autofluorescence in the *** alimentary canal with SBB treatment,which may improve the use of immunofluorescence labeling in this *** method may also have a wide range of uses by reducing the autofluorescence in other arthropod species.

关键词： endosymbionts gut immunofluorescence Liberibacter pathogen psyllid vector

Molecular Dynamics Simulation of Xe Behavior in U-Mo Alloys Fuel

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Chinese Physics Letters 2014年第4期31卷 130-133页

作者： xiao Hong-Xing TANG Rui tian xiao-Feng LONG Chong-Sheng Science and Technology on Reactor Fuel and Materials Laboratory Nuclear Power Institute of China Chengdu 610041 The College of Nuclear Technology and Automation Engineering Chengdu University of Technology Chengdu 610059

Classical molecular dynamics simulations are used to investigate the fission gas Xe behavior in a U-Mo alloy fuel matrix. The embedded atom method potential proposed by Smirnova et al. is used to describe the U-Mo-Xe system. The results show that the initial configuration of interstitial Xe atoms in U-Mo alloys is very instable and has a strong tendency to get together and to form a Xe bubble by ejecting the adjacent U atoms and Mo atoms from their former normal lattice sites. The pressure in Xe bubbles is initially quite high and then drops with increasing Xe concentration obviously. The matrix swelling of U-Mo alloys associated with the Xe bubble growth follows approximately a linear relationship with the ratio of Xe to U at low Xe concentration while the rate of swelling increases rapidly at high Xe concentration. The simulation results are in good agreement with the experimental data. The recovery of the damaged structure in the U-Mo alloys matrix is also investigated. It is shown that a damaged structure cannot be recovered completely after a system is relaxed for a long time while still having lots of defects.

关键词： Alloys Fuel Molecular fission