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Effect of inorganic salt on the thermal degradation of nitrocellulose and reaction mechanism of its mixture

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Defence Technology（防务技术） 2023年第9期27卷 111-118页

作者： Guo-zhong xu xu Gao Mi Li zhong-xuan Han Lin Jiang School of Mechanical Engineering Nanjing University of Science and TechnologyChina

In this study,to better understand the reaction mechanism between inorganic salts and nitrocellulose,CaCO_(3) and Li_(2)CO_(3) were evaluated with respect to their effects on the thermal degradation of NC in nitrogen atmosphere using TG/DSC at three different heating rates(2,5,10 K/min).The numerical relationship between activation energy(E)and conversion rate was obtained by FWO and KAS method,and it was discovered that CaCO_(3) could improve the thermal stability of *** energy values were calculated by Kissinger method,and it was found that NC that contain Li2CO3had the highest activation energy while NC containing CaCO3had the lowest E *** combining the thermal analysis data with Malek method,the most probable mechanism model of thermal degradation is obtained as Sesták-Berggren model,which expression is f(α)=α^(m)(1-α)^(n).As a result of this study,there are certain guiding principles that can be applied to the pyrolysis reaction model and to the actual production process of nitrocellulose.

关键词： Thermal analysis Thermal decomposition mechanism Malek method Nitrocellulose Inorganic salt

Research of Step-down Stress Accelerated Degradation Data Assessment Method of a Certain Type of Missile Tank

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Chinese Journal of Aeronautics 2012年第6期25卷 917-924页

作者： YAO Jun xu Mingge zhong Weiqiang School of Reliability and System Engineering Beihang University Beijing 100191 China

The performance degradation rates of the missile tank are generally time-varying functions uneasily evaluated by general classical evaluation methods. This paper develops a segmented nonlinear accelerated degradation model （SNADM） based on the equivalent method of accumulative damage theory, which tackles the problem that product life is difficult to be determined with degradation rate being a function of the variable of time. A segmented expression of the function of population accumulative degradation is derived. And combined with nonlinear function, an accelerated degradation function, i.e., SNADM is obtained. The parameters of the SNADM are identified by numerical iteration, and the statistical function of degradation track is extrapolated. The reliability function is determined through the type of random process of the degradation distribution. Then an evaluation of product storage life is undertaken by combining the statistical function of degradation track, reliability function and threshold. An example of a missile tank undergoes a step-down stress accelerated degradation test （SDSADT）, in which the results with the SNADM and the classical method are evaluated and compared. The technology introduced is validated with the resultant coincidence of both evaluated and field storage lives.

关键词： reliability accelerated degradation model step-down stress testing life assessment cumulative damage

The Parabrachial Nucleus as a Key Regulator of Neuropathic Pain

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Neuroscience Bulletin 2021年第7期37卷 1079-1081页

作者： Zilong Wang Zhen-zhong xu Department of Anesthesiology Center for Translational Pain MedicineDuke University Medical CenterDurhamNC 27710USA SUSTech Center for Pain Medicine School of MedicineSouthern University of Science and TechnologyShenzhen 518055China Department of Neurobiology and Department of Anesthesiology of the First Affiliated Hospital NHC and CAMS Key Laboratory of Medical NeurobiologyZhejiang University School of MedicineHangzhou 310058ZhejiangChina

Neuropathic pain is a chronic pain caused by peripheral or central nervous system injury or diseases that affect the somatosensory nervous *** is usually associated with abnormal sensations called dysesthesia and exaggerated pain from normally innocuous stimuli(allodynia)or noxious stimuli(hyperalgesia),and also aversive emotional responses[1,2].Neuropathic pain can be very difficult to treat,as classical analgesics like opioids produce inadequate pain relief and may cause tolerance and hyperalgesia,and even addiction after long-term use[3].Thus,it is of critical importance to study the mechanisms of development,maintenance,and resolution of neuropathic *** study from ***’s research team at Zhejiang University reveals a critical regulatory mechanism for neuropathic pain[4].

关键词： sensation diseases opioid

One-Dimensional ZnO Nanostructures： Solution Growth and Functional Properties

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Nano Research 2011年第11期4卷 1013-1098页

作者： Sheng xu zhong Lin Wang School of Materials Science and Engineering Georgia Institute of Technology Atlanta Georgia 30332-0245 USA

One-dimensional （1D） ZnO nanostructures have been studied intensively and extensively over the last decade not only for their remarkable chemical and physical properties, but also for their diverse current and future technological applications. This article gives a comprehensive overview of the progress that has been made within the context of 1D ZnO nanostructures synthesized via wet chemical methods. We will cover the synthetic methodologies and the corresponding growth mechanisms, various nanostructures grown, their doping and alloying, and position-controlled growth on substrates. Finally, we will review their functional properties in catalysis, hydrophobic surface modification, sensing, and electronic, optical, optoelectronic, and energy harvesting devices.

关键词： ZnO one dimensional nanostructures solution growth electronic optical optoelectronic energy harvesting devices

Pollution characteristics of polycyclic aromatic hydrocarbons (PAHs) in oily sludge from the zhongyuan Oilfield and its peripheral soils

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Chinese Journal Of Geochemistry 2009年第2期28卷 176-183页

作者： KUANG Shaoping xu zhong Qingdao University of Science and Technology Qingdao 266042 China

The purpose of this study is to determine the degree of contamination caused by polycyclic aromatic hydrocarbons (PAHs) in oily sludge and soils around it in the zhongyuan Oilfield. The contents of polycyclic aro-matic hydrocarbons in oily sludge samples were determined with HPLC. The contents of PAHs of oily sludge from three different oil production plants vary from high to low in the order of the Wenming oily sludge dumping site of No. 3 Oil Production Plant (3W)>the Mazhai oily sludge dumping site of No. 3 Oil Production Plant (3M)>the Wen'er oily sludge dumping site of No. 4 Oil Production Plant (4W). Naphthalene, acenaphthylene, acenaphthene, fluorine and phenanthrene are the major pollutants of PAHs in oily sludge. The contents of PAHs in soil samples around the oily sludge dumping sites vary widely from 434.49 to 2408.8 ng/g. Naphthalene, acenaphthene, fluorine, phenanthrene and pyrene are the characteristic factors of PAHs in soil samples of 3M and 3W, and naphthalene, acenaphthene, fluorine and phenanthrene are the characteristic factors of PAHs in soil samples of 4W. According to these data and the ratios of Fl/Py, PAHs in oily sludge samples come mainly from petrogenic sources, and soil samples are divided into petrogenic soil samples and mixed-source soil samples, and both petrogenic and pyrogenic soil samples in terms of the sources of PAHs. The classification by Nemero index P indicates that soils around the oily sludge dumping sites have been seriously polluted.

关键词：土壤样品含油污泥多环芳烃污染特征 PAHs 中原油田高效液相色谱法内梅罗指数

Synthesis and Crystal Structure of 2-tert-Butyl-5-(4-tert-butylbenzylthio)-4-chloropyridazin-3(2H)-one

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Chemical Research in Chinese Universities 2006年第6期22卷 763-764页

作者： xu Liang-zhong YU Guan-ping xu zhong-jie ZHANG Gong-sheng ZHAI Zhi-wei College of Chemistry and Molecular Engineering Qingdao University of Science and Technology Qingdao 266042 P. R. China

The title compound, 2-ten-butyl-6 （4-ten -butylbenzylthio） -4-chloropyridazin-3 （ 2H ） -one, was synthesized from 1 -ten-butylhydrazine, （ Z ） -2,3 -dichloro-3 -formylacrylic acid and （ 4 -tert -butylphenyl ） methanethiol in several steps. It crystallized in an orthorhombic space group Pnma with Mr = 364. 93 （ C19H25 ClN2OS）, a = 1. 0091 （2） nm, b = 0.7076（2） nm, c=2. 8103（5） nm, V=2.0066（6） nm^3, Z=4, Dc =1. 192 g/cm^3, F（000） =765, μ=0.301 mm , final R1 = 0. 0665, and wR = 0. 1913 for 1927 unique reflections. Inter- and intramolecular hydrogen bond C-H…O interactions stabilize the structure.

关键词： Pyridaben Synthesis Crystal structure

An Exact Generalized Test for Homogeneity of Inverse Gaussian Scale Parameters

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Acta Mathematicae Applicatae Sinica 2019年第4期35卷 761-769页

作者： xu-hua LIU Xing-zhong xu Wei-yan MU Department of Mathematics China Agricultural University Beijing 100083 China College of Mathematics Beijing Institute of Technology Beijing 100081 China School of Science Beijing University of Civil Engineering and Architecture Beijing 100044 China

In this paper, we propose a new generalized p-value for testing homogeneity of scale parameters λi from k independent inverse Gaussian populations. The proposed generalized p-value is proved to have exact frequentist property, and it is also invariant under the group of scale transformation. Simulation results indicate that the proposed test is better than existing approximate χ^2 test.

关键词： Inverse Gaussian distribution Generalized p-value Exact frequentist property

Estimation of velocity potential of water waves using a Luenberger-like observer

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Science China(Information Sciences) 2020年第12期63卷 139-152页

作者： Yang YU Hai-Long PEI Cheng-zhong xu Key Laboratory of Autonomous Systems and Networked Control Ministry of EducationSouth China University of Technology Unmanned Aerial Vehicle Systems Engineering Technology Research Center of Guangzhou South China University of Technology LAGEPP University Claude Bernard-Lyon 1

We propose a Luenberger-like observer for a water wave system. The water wave dynamics are assumed to be governed by the linearized water wave equation(LWWE). Our proposed observer estimates the velocity potential of water waves by measuring only the surface wave elevation. The information of the water-wave velocity field is then extracted from the gradient of the velocity potential. It is shown that the estimation error of the observer converges exponentially to zero as time tends to infinity. Furthermore,we numerically solve the LWWE and observer equation by the finite difference method. The efficiency of our proposed numerical scheme and the performance of the observer are validated by numerical simulation results.

关键词： linearized water wave equation LWWE Luenberger-like observer numerical simulations

Topological Entropy of a Class of Subshifts of Finite Type

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Acta Mathematica Sinica,English Series 2018年第12期34卷 1765-1777页

作者： Jin zhong xu Lan Yu WANG Key Laboratory of Space Utilization Technology and Engineering Center for Space Utilization Chinese Academy of Sciences Beijing 100094 P. R. China University of Chinese Academy of Sciences Beijing 100049 P. R. China Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 P. R. China

In this paper, we construct a special class of subshifts of finite type. By studying the spectral radius of the transfer matrix associated with the subshift of finite type, we obtain an estimation of its topological entropy. Interestingly, we find that the topological entropy of this class of subshifts of finite type converges monotonically to log（n ＋ 1）（a constant only depends on the structure of the transfer matrices） as the increasing of the order of the transfer matrices.

关键词： Symbolic dynamical system subshift of finite type topological entropy transfer matrix,Toeplitz matrix