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Conservation laws of the complex short pulse equation and coupled complex short pulse equations

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Communications in Theoretical Physics 2022年第7期74卷 49-56页

作者： Lihua Zhang bo shen Shuxin Han Gangwei wang Lingshu wang School of Mathematics and Statistics Hebei University of Economics and BusinessShijiazhuang 050061China

In this paper, the complex short pulse equation and the coupled complex short pulse equations that can describe the ultra-short pulse propagation in optical fibers are investigated. The two complex nonlinear models are turned into multi-component real models by proper transformations. Lie symmetries are obtained via the classical Lie group method, and the results for the coupled complex short pulse equations contain the existing results as particular *** on the linearizing operator and adjoint linearizing operator for the two real systems,adjoint symmetries can be obtained. Explicit conservation laws are constructed using the symmetry/adjoint symmetry pair(SA) method. Relationships between the nonlinear selfadjointness method and the SA method are investigated.

关键词： complex short pulse equation coupled complex short pulse equations symmetries adjoint symmetries conservation laws SA method

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厚壁双金属复合管外胀成形工艺研究

北华大学学报（自然科学版） 2010年第1期11卷 92-96页

作者：贾建波徐岩王浩舟王慎波陆俊杰韩天春北华大学机械工程学院

采用卸载理论对厚壁双层金属复合管在胀形成形后接触面上的配合性质与材料力学性能之间的关系进行了分析和研究．利用内、外管周向应变的变形协调条件，得出了胀形力P，与内、外管之间残余接触压力P＇c的关系式．根据成形过程中残余接... 详细信息

采用卸载理论对厚壁双层金属复合管在胀形成形后接触面上的配合性质与材料力学性能之间的关系进行了分析和研究．利用内、外管周向应变的变形协调条件，得出了胀形力P，与内、外管之间残余接触压力P＇c的关系式．根据成形过程中残余接触压力的不同，得出了胀形力Pi的工作压力范围．采用***对厚壁双金属复合管外胀成形工艺进行了有限元分析和数值模拟．结果表明：采用适当的胀形类成形工艺，可以在卸载后使不同材料的厚壁双层金属复合管材呈紧密配合状态．

关键词：卸载理论双层金属管数值模拟紧配合

Soil calcium content as the driving factor for vegetative structure and soil microbial function diverging across a fire chronosequence of the boreal forests in northeast China

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Journal of Plant Ecology 2022年第2期15卷 372-384页

作者： Zhiyong Zhou Ying shen bo wang Huan Zhang Key Laboratory of Forest Ecosystem Process of Beijing Beijing Forestry UniversityBeijing 100083China

The role of biophysical variables in constructing community structure changes with the time since *** major objective of this study is to verify the transition stage and its underlying variables for the postfire forest and soil microbial function in the boreal forested area of China.A 50-year fire chronosequence was presented,and biomass of forbs,shrubs and woody plants was separately weighted to assess their contribution to the whole community with the year since fire(YSF).Simultaneously,soil biophysical properties were measured for stands in different time periods after *** microbial functions,*** efficiency(GE)and carbon use efficiency(CUE),were calculated based on ecoenzymatic and soil nutrient *** terms of vegetative structure,forbs’proportion decreased from 75%to 1.5%,but the proportion of woody plants increased from 0.04%to 70%across this fire *** and CUE of soil microorganisms averaged 0.242 and 0.236 and were significantly higher in 9,15 and 31 YSF than in 2 and 3 *** metal content was significantly increased at the late stage of this fire chronosequence,and soil calcium content showed a positive correlation with woody plant biomass and a negative correlation with soil microbial ***,the present work highlights that the time period of 15 and 31 YSF is a hallmark stage for aboveground vegetative structure and soil microbial function to change in different trends and that the calcium content may partly account for these two divergent trajectories.

关键词： vegetative recovery fire chronosequence soil microbial carbon use efficiency soil ecoenzymatic activity soil microbial biomass soil metal content

沈一平中西医结合治疗老年急性髓系白血病经验拾萃

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浙江中医药大学学报 2018年第9期42卷 723-726,734页

作者：张瑞丹王博沈一平浙江中医药大学第一临床医学院杭州310053 浙江中医药大学附属第一医院

[目的]总结沈一平主任中医师中西医结合治疗老年急性髓系白血病(acute myeloid leukemia,AML)的临床经验。[方法]通过跟诊、查房,收集沈师收治的老年AML患者病案,学习最新诊疗指南,阅读相关论文和相关古籍经典,从病因病机、治则治法等... 详细信息

[目的]总结沈一平主任中医师中西医结合治疗老年急性髓系白血病(acute myeloid leukemia,AML)的临床经验。[方法]通过跟诊、查房,收集沈师收治的老年AML患者病案,学习最新诊疗指南,阅读相关论文和相关古籍经典,从病因病机、治则治法等方面分析总结沈师中西医结合治疗老年AML的临床经验,并举验案佐证。[结果]沈师认为,老年AML病机多为虚实夹杂,患者先天禀赋不足、脾肾亏虚,热毒内侵,灼津为痰,痰瘀互结,邪蕴骨髓。沈师常用清热解毒药配合化疗,同时兼补益药益气扶正,达到治病而不伤正的目的,以"抗白延年汤"联合地西他滨+化疗为基础方案,并根据患者的临床表现、证型转变进行加减治疗,临床疗效显著。所举案例热毒内侵、痰瘀互结,在化疗的基础上配合清热解毒兼益气扶正治疗,获得较好的效果。[结论]沈师善于融合中西两法,辨证、辨病相结合,运用清热法联合补法治疗老年AML,值得推广学习。

关键词：老年急性髓系白血病虚实夹杂抗白延年汤中西医结合医案沈一平临床经验

ZnSe quantum dots downshifting layer for perovskite solar cells

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Journal of Energy Chemistry 2018年第3期27卷 736-741页

作者： Bei wang bo Li Ting shen Mengjie Li Jianjun Tian Institute for Advanced Materials and Technology University of Science and Technology Beijing

To date, the instability of organometal halide perovskite solar cells（PSCs） has become the focus issue that limits the development and long-term application of PSCs. both the ultraviolet（UV） rays in sunlight and moisture in air can significantly accelerate the disintegration of the perovskite. Here, we introduced a Zn Se quantum dots layer as downshifting materials, which was spin-coated onto the backside of *** layer converted the UV rays into visible light to prevent the destruction of PSCs as well as increase the light harvesting of the perovskite layer. Under the UV irradiation in the moisture ambient（40%）, the destruction speed of the unencapsulated perovskite films were also delayed evidently. In addition, the power conversion efficiency（PCE） of the PSCs was increased from 16.6% to 17.3% due to the increase of the visible light absorbance of the perovskite.

关键词： ZnSe Quantum dots Perovskite solar cells Downshifting Stability

Wave propagation in graphene reinforced piezoelectric sandwich nanoplates via high-order nonlocal strain gradient theory

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Acta Mechanica Sinica 2021年第9期37卷 1446-1456,I0003页

作者： Biao Hu Juan Liu Yuxing wang bo Zhang Huoming shen Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and EngineeringSouthwest Jiao Tong UniversityChengdu610031China

Αn analytical method is developed to explore the wave propagation characteristics of piezoelectric sandwich nanoplates in the present *** sandwich nanoplates are composed of a graphene reinforced composite core layer with two piezoelectric surface layers exposed to electric *** material properties of the nanocomposite layer are given by the Halpin–Tsai model and mixture’s *** Euler–Lagrange equation of the nanoplates is obtained by Hamilton's principle and first-order shear deformation ***,combining the high-order nonlocal strain gradient theory with the hygrothermal constitutive relationship of composite nanoplates,the nonlocal governing equations are ***,numerical studies are conducted to demonstrate the influences of scale parameters,applied external voltage,temperature variation,moisture variation,graphene size,and weight fraction on wave *** results reveal that low-order and high-order nonlocal parameters and length scale parameters have different effects on wave *** wave frequency can be reduced by increasing temperature and the thickness of *** could facilitate the investigation of the dynamic properties of graphene nanocomposite structures.

关键词： Wave propagation High-order nonlocal strain gradient theory Piezoelectric sandwich nanoplates Graphene platelets Hygrothermal environment

Deep postbuckling and nonlinear bending behaviors of nanobeams with nonlocal and strain gradient effects

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Applied Mathematics and Mechanics(English Edition) 2019年第4期40卷 515-548页

作者： bo ZHANG Huoming shen Juan LIU Yuxing wang Yingrong ZHANG School of Mechanics and Engineering Southwest Jiaotong University Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province

In this paper, multi-scale modeling for nanobeams with large deflection is conducted in the framework of the nonlocal strain gradient theory and the Euler-Bernoulli beam theory with exact bending curvature. The proposed size-dependent nonlinear beam model incorporates structure-foundation interaction along with two small scale parameters which describe the stiffness-softening and stiffness-hardening size effects of nanomaterials, respectively. By applying Hamilton's principle, the motion equation and the associated boundary condition are derived. A two-step perturbation method is introduced to handle the deep postbuckling and nonlinear bending problems of nanobeams analytically. Afterwards, the influence of geometrical, material, and elastic foundation parameters on the nonlinear mechanical behaviors of nanobeams is discussed. Numerical results show that the stability and precision of the perturbation solutions can be guaranteed, and the two types of size effects become increasingly important as the slenderness ratio increases. Moreover, the in-plane conditions and the high-order nonlinear terms appearing in the bending curvature expression play an important role in the nonlinear behaviors of nanobeams as the maximum deflection increases.

关键词： nanobeam nonlocal strain gradient theory two-step perturbation method,deep postbuckling

Parameter Estimation for the Discretely Observed Vasicek Model with Small Fractional Lévy Noise

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Acta Mathematica Sinica,English Series 2020年第4期36卷 443-461页

作者： Guang Jun shen Qing bo wang Xiu Wei YIN Department of Mathematics Anhui Normal UniversityWuhu 241000P.R.China

The statistical inference of the Vasicek model driven by small Levy process has a long *** this paper,we consider the problem of parameter estimation for Vasicek model dX_t=(μ-θX_t)dt+εdL_t^d,t∈[0,1],X_0=x_0,driven by small fractional Lévy noise with the known parameter d less than one half,based on discrete high-frequency observations at regularly spaced time points{t_i=i/n,i=1,2,...,n}.For the general case and the null recurrent case,the consistency as well as the asymptotic behavior of least squares estimation of unknown parametersμandθhave been established as small dispersion coefficientε→0 and large sample size n→∞simultaneously.

关键词： Ornstein–Uhlenbeck process fraction Lévy processes least squares estimator consistency asymptotic distribution

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缺陷对单层硅烯纳米梁振动频率的影响

原子与分子物理学报 2025年第6期42卷 76-82页

作者：张文博王静新疆大学物理科学与技术学院乌鲁木齐830017

由于硅纳米谐振器在量子计算、传感器、医学等方面存在广泛的应用,使其物理性质的研究具有重要意义.本文通过分子动力学模拟方法研究了掺杂元素、空位缺陷、掺杂浓度对单层硅烯纳米梁振动特性的影响.研究结果表明,单层硅烯纳米梁的振动... 详细信息

由于硅纳米谐振器在量子计算、传感器、医学等方面存在广泛的应用,使其物理性质的研究具有重要意义.本文通过分子动力学模拟方法研究了掺杂元素、空位缺陷、掺杂浓度对单层硅烯纳米梁振动特性的影响.研究结果表明,单层硅烯纳米梁的振动频率随着纳米梁长度的增加而减小.单元素、双元素掺杂均会导致单层硅烯纳米梁的振动频率的增加,且随着掺杂浓度的增加纳米梁的振动频率整体呈现增大的趋势.此外,单空位缺陷会导致单层硅烯纳米梁的振动频率随着缺陷浓度的增加而减小.掺杂-单空位缺陷的单层硅烯纳米梁的振动频率则呈现了随着掺杂浓度的增加先减小后增加的变化趋势.这些变化规律均是由掺杂元素、空位缺陷以及它们共同作用的结果.此研究结果对硅烯纳米谐振器,振荡器等纳米器件的设计具有一定的理论指导意义.

关键词：硅烯掺杂振动频率分子动力学

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