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239Pu alpha spectrum analysis based on PIPS detector response function and variations with vacuum and distance

Nuclear Science and Techniques 2017年第1期28卷 20-26页

作者： Rui Shi xian-Guo Tuo Huai-Liang Li Jian-Bo Yang Yi Cheng Hong-long zheng Provincial Key Lab of Applied Nuclear Techniques in Geosciences Chengdu University of TechnologyChengdu 610059 China Sichuan University of Science and Engineering Zigong 643000 China Fundamental Science on Nuclear Wastes and Environmental Safety Laboratory Southwest University of Science and Technology Mianyang 621010 China

Effect factors of the absorption of the source,air,entrance window,and dead layer of a detector must be considered in the measurement of monoenergetic alpha particles,along with statistical noise and other factors that collectively cause the alpha spectrum to exhibit a well-known low-energy ***,the estabUshment of an alpha spectrum detector response function from the perspective of a signaling system must consider the various factors mentioned *** detector response function is the convolution of an alphaparticle pulse function,two exponential functions,and a Gaussian function,followed by calculation of the parameters of the detector response function using the weighted leastsquares fitting method as proposed in this *** our experiment,^(239)Pu alpha spectra were measured by a highresolution,passivated implanted planar silicon(PIPS)detector at 10 levels of vacuum and 10 source-detector *** spectrum-fitting results were excellent as evaluated by reduced Chi-square(x^2) and correlation ***,the variation of parameters with vacuum level and source-detector distance was *** demonstrate that σ,τ_1,and τ_2 exhibit no obvious trend of variation with vacuum in the range 2000-20,000 mTorr,and at a confidence level of 95%,the values of τ_1 and τ_2 decline in a similar fashion with source-detector distance by the power exponential function,while the value of a declines linearly.

关键词： Alpha spectrum Detector response function Weighted least squares PIPS detector

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Integration of cryogenic trap to gas chromatography-sulfur chemiluminescent detection for online analysis of hydrogen gas for volatile sulfur compounds

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Chinese Chemical Letters 2021年第11期32卷 3440-3445页

作者： Yi Pan Fan-Feng Deng zheng Fang Han-Jiao Chen Zhou long xian-Deng Hou Analytical Testing Center Sichuan UniversityChengdu 610064China Institute of Chemistry National Institute of Measurement and Testing TechnologyChengdu 610021China

Hydrogen fuel cells are among the promising energy sources worldwide,which could accomplish cyclic production of energy and avoid the emission of green-house or contaminative ***,sulfur compounds(SCs)even at trace level(nmol/mol)are usually involved in cell construction and further H_(2)production,which would cause degradation of the catalysts and shorten the lifetime of the fuel ***,the highly reactive SCs could cause varied species and concentrations of them in complex matrices,so online rather than offline analysis of SCs in H_(2)would be *** this context,we developed a new system combining online cryogenic preconcentration of nine SCs and subsequent determination by GC-SCD(sulfur chemiluminescent detector),with the correlation coefficients of the calibration curves higher than 0.999,calculated limits of detection no higher than 0.050 nmol/mol,analytical time around 30 min per sample,and satisfactory precision and accuracy(RSD<5%and SD<15%).The analytical performance was much better than or at least comparable to the previously reported and the developed system was successfully applied for real sample analysis.

关键词： Gas-chromatography Hydrogen fuel cell Online cryogenic trap Sulfur chemiluminescent detector Volatile sulfur compounds

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Fertilizer ^(15)N Accumulation, Recovery and Distribution in Cotton Plant as Affected by N Rate and Split

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Journal of Integrative Agriculture 2013年第6期12卷 999-1007页

作者： YANG Guo-zheng CHU Kun-yan TANG Hao-yue NIEYi-chun ZHANG xian-long College of Plant Science and Technology Huazhong Agricultural University Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River Ministry of Agriculture

N fertilization of 300 kg N ha-1 is normally applied to cotton crops in three splits： pre-plant application （PPA, 30%）, first bloom application （FBA, 40%） and peak bloom application （PBA, 30%） in the Yangtze River Valley China. However, low fertilizer N plant recovery （NPR）（30-35%） causes problems such as cotton yield stagnation even in higher N rate, low profit margin of cotton production and fertilizer release to the environment. Therefore, it is questioned： Are these three splits the same significance to cotton N uptake and distribution？ An outdoor pot trial was conducted with five N rates and 15 N labeled urea to determine the recovery and distribution of 15N from different splits in cotton （Gossypium hirsutum L. cv. Huazamian H318） plant. The results showed that, cotton plant absorbed fertilizer 15N during the whole growing period, the majority during flowering for 18-20 d regardless of N rates （150-600 kg ha-1）. Fertilizer 15N proportion to the total N accumulated in cotton plant increased with N rates, and it was the highest in reproductive organs （88% averaged across N rates） among all the plant parts. FBA had the highest NPR （70%）, the lowest fertilizer N lose （FNL, 19%）, and the highest contribution to the fertilizer 15N proportion to the total N （46%） in cotton plant, whereas PPA had the reverse effect. It suggests that FBA should be the most important split for N absorption and yield formation comparatively and allocating more fertilizer N for late application from PPA should improve the benefit from fertilizer.

关键词： cotton fertilizer N split application NPR (fertilizer N plant recovery)

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Stability for Impulsive Functional Differential Equations with Infinite Delays

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Acta Mathematica Sinica,English Series 2010年第5期26卷 909-922页

作者： xian long FU Lei ZHOU Department of Mathematics East China Normal University Shanghai 200241 P. R. China

In this paper, some theorems of uniform stability and uniform asymptotic stability for impulsive functional differential equations with infinite delay are proved by using Lyapunov functionals and Razumikhin techniques... 详细信息

关键词： impulsive functional equation infinite delay stability Lyapunov functional

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Asymptotic Behaviors of a Size-structured Population Model

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Acta Mathematicae Applicatae Sinica 2017年第4期33卷 1025-1042页

作者： xian-long FU Qiong WU Department of Mathematics Shanghai Key Laboratory of PMMP East China Normal University Shanghai 200241 China

In this paper we devote ourselves to the study of the asymptotic behavior of a size-structured pop- ulation dynamics with random diffusion and delayed birth process. Within a semigroup framework, we discuss the local stability and asynchrony respectively for the considered population system under some conditions. We use for our discussion the techniques of operator matrices, Hille-Yosida operators, positivity, spectral analysis as well as Perron-Frobenius theory.

关键词： Population dynamics C0-semigroup stability asynchrony.

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Nonlinear robust control of a quadrotor helicopter with finite time convergence

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Control Theory and Technology 2018年第2期16卷 133-144页

作者： Guozhou zheng Bin xian School of Electrical and Information Engineering Tianjin University Tianjin 300072 China

In this paper, the control problem for a quadrotor helicopter which is subjected to modeling uncertainties and unknown external disturbance is investigated. A new nonlinear robust control strategy is proposed. First, a nonlinear complementary filter is developed to fuse the raw data from the onboard barometer and the accelerometer to decrease the negative effects from the noise associated with the low-cost onboard sensors Then the adaptive super-twisting methodology is combined with a backstepping method to formulate the nonlinear robust controller for the quadrotor＇s attitude angles and the altitude position. Lyapunov based stability analysis shows that finite time convergence is ensured for the closed-loop operation of the quadrotor＇s roll angle, pitch angle, row angle and the altitude position. Real-time flight experimental results, which are performed on a quadrotor flight testbed, are included to demonstrate the good control performance of the proposed control methodology.

关键词： Quadrotor nonlinear control finite time convergence real-time experiment

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Approximate Controllability of Second-order Semilinear Evolution Systems with Finite Delay

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Acta Mathematicae Applicatae Sinica 2021年第3期37卷 573-589页

作者： Xiao-feng SU xian-long FU School of Mathematical Sciences Fudan UniversityShanghai 200433China School of Mathematical Sciences Shanghai Key Laboratory of PMMPEast China Normal UniversityShanghai200241China

In this work,we study the approximate controllability for a class of semilinear second-order control systems with finite *** conditions for approximate controllability are established by constructing fundamental solutions and using the resolvent condition and techniques on cosine family of linear *** illustrate the applications of the obtained results,an example is provided in the end.

关键词： approximate controllability second-order evolution equation fundamental solution cosine operator

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Characterization of Pattern Formation from Modulation Instability in the Cubic Schrodinger Equation

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Chinese Physics Letters 1998年第9期15卷 659-661页

作者： long Tao HE xian-tu Graduate School China Academy of Engineering PhysicsBeijing 100088 Institute of Applied Physics and Computational Mathematics Beijing 100088 Institute of Theoretical Physics Chinese Academy of SciencesBeijing 100080

The study of pattern dynamics in a Hamiltonian system(HS)having an infinite number of degree of freedom is very difficult due to the absence of attractors in such *** this letter,we propose a useful method that only a few representative manifolds in phase space are investigated,and it can be used to reveal the pattern formation of *** conserved cubic Schrödinger equation is *** a special model is chosen,this method can be applied to more general case such as the near-integrable HS.

关键词： integrable letter infinite

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Novel Stability Criteria for Linear Time-Delay Systems Using Lyapunov-Krasovskii Functionals With A Cubic Polynomial on Time-Varying Delay

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IEEE/CAA Journal of Automatica Sinica 2021年第1期8卷 77-85页

作者： xian-Ming Zhang Qing-long Han Xiaohua Ge the School of Software and Electrical Engineering Swinburne University of TechnologyMelbourneVIC 3122Australia

One of challenging issues on stability analysis of time-delay systems is how to obtain a stability criterion from a matrix-valued polynomial on a time-varying *** first contribution of this paper is to establish a necessary and sufficient condition on a matrix-valued polynomial inequality over a certain closed *** degree of such a matrix-valued polynomial can be an arbitrary finite positive *** second contribution of this paper is to introduce a novel LyapunovKrasovskii functional,which includes a cubic polynomial on a time-varying delay,in stability analysis of time-delay *** on the novel Lyapunov-Krasovskii functional and the necessary and sufficient condition on matrix-valued polynomial inequalities,two stability criteria are derived for two cases of the time-varying delay.A well-studied numerical example is given to show that the proposed stability criteria are of less conservativeness than some existing ones.

关键词： Bessel-Legendre inequality matrix-valued polynomial inequalities stability time-varying delay time-delay systems

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Preparation and Characterization of Microencapsulated Hexadecane Used for Thermal Energy Storage

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Chinese Chemical Letters 2004年第6期15卷 729-732页

作者： Guang long ZOU Zhi Cheng TAN Xiao zheng LAN Li xian SUN Tao ZHANG Dalian Institute of Chemical Physics Chinese Academy of SciencesDalian116023

Polyurea microcapsules about 2.5 μm in diameter containing phase change material for thermal energy storage application were synthesized and characterized by interfacial polycondensation method with toluene-2,4-diisocyanate and ethylenediamine as monomers in an emulsion system. Hexadecane was used as a phase change material and OP, which is nonionic surfactant, and used as an emulsifier. The chemical structure and thermal behavior of the microcapsules were investigated by FTIR and thermal analysis respectively. The results show encapsulated hexadecane has a good potential as a solar energy storage material.

关键词： Phase change material microcapsule interfacial polycondensation energy storage.

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