Decompositions of the Kadomtsev-Petviashvili equation and their symmetry reductions

Starting with a decomposition conjecture,we carefully explain the basic decompositions for the Kadomtsev-Petviashvili(KP)equation as well as the necessary calculation procedures,and it is shown that the KP equation allows the Burgers-STO(BSTO)decomposition,two types of reducible coupled BSTO decompositions and the BSTO-KdV decomposition.Furthermore,we concentrate ourselves on pointing out the main idea and result of Bäcklund transformation of the KP equation based on a special superposition principle in the particular context of the BSTO decompositions.Using the framework of standard Lie point symmetry theory,these decompositions are studied and the problem of computing the corresponding symmetry constraints is treated.

心血管植介入体表面抗凝涂层近十年进展

心血管植介入体已被广泛用于治疗各种心血管疾病.然而,植介入体表面和血液之间的接触会导致血栓,进而显著增加了血栓疾病的发病率和死亡率.为降低血栓风险,在植介入体表面修饰抗凝涂层是预防血栓的常用方法.本文中作者综述了近十年中不同心血管植介入体表面的抗凝涂层技术,重点回顾了应用于四种典型的心血管植介入体(包括人工心脏瓣膜、血管支架、心室辅助装置和导管)的抗凝涂层的进展.最后,总结了每种植介入体表面的理想设计,并展望了心血管植介入体表面抗凝涂层技术的未来,对推进心血管植介入体的设计开发和应用具有重要意义.

Higher Dimensional Camassa–Holm Equations

Utilizing some conservation laws of the(1+1)-dimensional Camassa–Holm(CH) equation and/or its reciprocal forms, some(n+1)-dimensional CH equations for n ≥ 1 are constructed by a modified deformation algorithm.The Lax integrability can be proven by applying the same deformation algorithm to the Lax pair of the(1+1)-dimensional CH equation. A novel type of peakon solution is implicitly given and expressed by the Lambert W function.

微流控技术在机械工程-生命科学交叉领域的应用

以微流控技术为研究对象,介绍了微流控芯片的制备材料及工艺,阐述了微流控技术在生命科学交叉领域的应用,主要从生物检测、体外结构仿生制造及可控释放的药物载体制备三方面展开介绍;从芯片结构设计及制备、功能模块集成、过程调控等方面入手,探讨了所涉及的关键技术;展望了微流控技术在机械工程-生命科学交叉领域的应用前景。

线接触交错轴斜齿轮-面齿轮副精确齿面造型及啮合仿真

给出了线接触交错轴斜齿轮-面齿轮副精确齿面造型。基于啮合理论建立了交错轴斜齿面齿轮齿面数学模型,并计算出齿面离散数据点,根据齿面均匀离散点的输出数据,对齿面进行重构,实现了面齿轮的精确实体造型,并进行啮合仿真,采用齿面偏差法对生成的实体模型精度进行了评估,该模型可用于面齿轮数字化设计和制造。

螺旋锥齿轮三维齿面接触分析研究

以往螺旋锥齿轮齿面接触分析过程中是通过二维齿面接触分析实现,为获得更直观齿面接触分析效果,采用数值法求得了螺旋锥齿轮三维齿面接触区。基于螺旋锥齿轮齿坯参数、刀具参数及安装调整参数建立螺旋锥齿轮数学模型,在此基础上建立螺旋锥齿轮虚拟装配数学模型,得到虚拟啮合的数学模型,采用数值法求解螺旋锥齿轮啮合过程中的接触迹线以及瞬时三维接触椭圆接触,最终得到螺旋锥齿轮齿面三维接触区。通过实际算例验证了相关算法的正确性。

3D打印术前虚拟仿真计划在复杂髋臼骨折治疗中的应用:前瞻性随机对照

背景:复杂髋臼骨折的治疗目前仍然是骨科医生面临的最具挑战性的任务之一,骨折的准确评估和术前计划对于良好的复位至关重要。采用计算机辅助虚拟手术程序以及患者个体化的3D打印模型预成型钢板为复杂髋臼骨折提供了准确、合理的手术方案。目的:评估基于3D打印技术的术前虚拟仿真计划在复杂髋臼骨折手术治疗中的可行性、准确性和有效性。方法:选择2018年3月至2020年8月滕州市中心人民医院创伤骨科收治的28例复杂髋臼骨折患者,随机分为2组。试验组13例采用基于3D打印技术的术前虚拟仿真计划,钢板预成型进行切开复位钢板内固定;对照组15例采用传统方法进行切开复位钢板内固定。比较两组患者术中情况和术后疗效。结果与结论:(1)试验组的手术时间、术中出血量、术中输血量、术中透视次数、术中器械时间均少于对照组,差异有显著性意义(P<0.05);两组患者的住院时间比较,差异无显著性差异(P>0.05);(2)两组患者术后随访6-18个月,试验组患者的并发症发生率、骨折愈合时间均优于对照组,差异有显著性意义(P<0.05);(3)试验组患者的术后即刻骨折复位质量Matta影像学评分、末次随访时髋关节功能Merle d’Aubigne&Postel评分高于对照组,差异有显著性意义(P<0.05);(4)提示基于3D打印技术的术前虚拟仿真计划是可行的、准确的,可为复杂髋臼骨折的术前计划和精确固定提供有效手段,从而改善修复效果。

A more general form of lump solution,lumpoff,and instanton/rogue wave solutions of a reduced (3+1)-dimensional nonlinear evolution equation

In this manuscript,a reduced(3+1)-dimensional nonlinear evolution equation is studied.We first construct the bilinear formalism of the equation by using the binary Bell polynomials theory,then explore a lump solution to the special case for z=x.Furthermore,a more general form of lump solution of the equation is found which possesses seven arbitrary parameters and four constraint conditions.By cutting the lump by the induced soliton(s),lumpoff and instanton/rogue wave solutions are also constructed by the more general form of lump solution.

Painlevé property, local and nonlocal symmetries, and symmetry reductions for a (2+1)-dimensional integrable KdV equation

The Painlevé property for a(2+1)-dimensional Korteweg–de Vries(KdV) extension, the combined KP3(Kadomtsev–Petviashvili) and KP4(cKP3-4), is proved by using Kruskal’s simplification. The truncated Painlevé expansion is used to find the Schwartz form, the Bäcklund/Levi transformations, and the residual nonlocal symmetry. The residual symmetry is localized to find its finite Bäcklund transformation. The local point symmetries of the model constitute a centerless Kac–Moody–Virasoro algebra. The local point symmetries are used to find the related group-invariant reductions including a new Lax integrable model with a fourth-order spectral problem. The finite transformation theorem or the Lie point symmetry group is obtained by using a direct method.

Time-sensitive prediction of NO_(2) concentration in China using an ensemble machine learning model from multi-source data

Nitrogen dioxide(NO_(2))poses a critical potential risk to environmental quality and public health.A reliable machine learning(ML)forecasting framework will be useful to provide valuable information to support government decision-making.Based on the data from1609 air quality monitors across China from 2014-2020,this study designed an ensemble ML model by integrating multiple types of spatial-temporal variables and three sub-models for time-sensitive prediction over a wide range.The ensemble ML model incorporates a residual connection to the gated recurrent unit(GRU)network and adopts the advantage of Transformer,extreme gradient boosting(XGBoost)and GRU with residual connection network,resulting in a 4.1%±1.0%lower root mean square error over XGBoost for the test results.The ensemble model shows great prediction performance,with coefficient of determination of 0.91,0.86,and 0.77 for 1-hr,3-hr,and 24-hr averages for the test results,respectively.In particular,this model has achieved excellent performance with low spatial uncertainty in Central,East,and North China,the major site-dense zones.Through the interpretability analysis based on the Shapley value for different temporal resolutions,we found that the contribution of atmospheric chemical processes is more important for hourly predictions compared with the daily scale predictions,while the impact of meteorological conditions would be ever-prominent for the latter.Compared with existing models for different spatiotemporal scales,the present model can be implemented at any air quality monitoring station across China to facilitate achieving rapid and dependable forecast of NO_(2),which will help developing effective control policies.

Searching For(2+1)-dimensional nonlinear Boussinesq equation from(1+1)-dimensional nonlinear Boussinesq equation

A novel(2+1)-dimensional nonlinear Boussinesq equation is derived from a(1+1)-dimensional Boussinesq equation in nonlinear Schr?dinger type based on a deformation algorithm.The integrability of the obtained(2+1)-dimensional Boussinesq equation is guaranteed by its Lax pair obtained directly from the Lax pair of the(1+1)-dimensional Boussinesq equation.Because of the effects of the deformation,the(2+1)-dimensional Boussinesq equation admits a special travelling wave solution with a shape that can be deformed to be asymmetric and/or multivalued.

锁骨钩钢板与Twin Tail TightRope带袢钛板内固定治疗肩锁关节脱位的有限元分析

目的 采用有限元分析方法比较锁骨钩钢板与Twin Tail TightRope带袢钛板内固定治疗肩锁关节脱位的生物力学特点。方法 获取一名健康志愿者的肩关节三维CT数据,利用有限元处理软件构建正常肩锁关节模型(模型A)、锁骨钩钢板固定模型(模型B)、Twin Tail TightRope带袢钢板固定模型(模型C)。设置荷载与边界条件,观察三种模型的位移和应力分布情况。结果 这3种模型的最大位移均位于锁骨中1/3近端,最大位移排序:模型A>模型C>模型B。模型B和模型C所有测量点的位移值差异无统计学意义(P<0.05)。这3种模型的锁骨上应力主要集中在锁骨中1/3位置,模型B和模型C的应力峰值均出现在锁骨上方钢板位置,整体应力峰值排序:模型C>模型B>模型A,锁骨中点的应力值和肩胛骨的应力峰值排序:模型A>模型B>模型C。结论 锁骨钩钢板和Twin Tail TightRope带袢钛板内固定治疗肩锁关节脱位均可提供足够的生物力学稳定性,非生理性的、增加的固定强度以及固定方式的不同也带来了相应并发症发生的风险,这些结果为临床医师合理选择肩锁关节脱位固定方式以及评估术后并发症发生风险提供了生物力学证据。

JAK/STAT通路抑制剂AG490对单核细胞增生李斯特菌感染的影响

为检测Janus激酶/信号转导与转录激活子(JAK/STAT)信号通路抑制剂α-氰-3, 4-二羟基-N-苄基肉桂酰胺(AG490)对单核细胞增生李斯特菌(LM)感染小鼠脑微血管内皮细胞和小鼠的影响,将不同浓度抑制剂AG490与细胞共同孵育,然后将LM分别感染细胞,MTT法检测不同浓度抑制剂AG490对细胞活性的影响;利用菌落计数法计算LM的侵袭率和胞内细菌数量,检测AG490对LM介导的小鼠生存曲线的影响;利用试剂盒检测抑制剂AG490对LM介导的乳酸脱氢酶(LDH)、白细胞介素-1β(IL-1β)、干扰素-γ(IFN-γ)和白细胞介素-6(IL-6)分泌的影响;利用实时定量PCR检测AG490对LM介导的炎性小体NLRP3的mRNA水平影响。结果:抑制剂AG490在5、10或15μmol/L浓度时未见对细胞活性有明显影响,AG490显著抑制了LM的侵袭、胞内和脏器内细菌数量,提高小鼠成活率,显著提高LM介导的LDH、IFN-γ、IL-6、IL-1β和NLRP3的mRNA水平。本研究表明,JAK/STAT信号通路抑制剂AG490可调控细胞内LM的存活,增强LM介导的细胞炎性小体水平,为调查LM引起脑膜炎的致病机制提供科学依据。

Fifth-Order Alice-Bob Systems and Their Abundant Periodic and Solitary Wave Solutions

The study on the nonlocal systems is one of the hot topics in nonlinear science. In this paper, the well-known fifth-order integrable systems including the Sawada-Kotera(SK) equation, the Kaup-Kupershmidt(KK) equation and the fifth-order Koterweg-de Vrise(FOKd V) equation are extended to a generalized two-place nonlocal form, the generalised fifth-order Alice-Bob system. The Lax integrability of two sets of Alice-Bob systems for all the SK, KK and FOKd V type systems are explicitly given via matrix Lax pairs. The ■ symmetry breaking and symmetry invariant periodic and solitary waves for one set of nonlocal SK, KK and FOKd V system are investigated via a special travelling wave solution ansatz.

Novel travelling wave structures:few-cyclepulse solitons and soliton molecules

We discuss a fifth order KdV(FOKdV)equation via a novel travelling wave method by introducing a background term.Results show that the background term plays an essential role in finding new abundant travelling wave structures,such as the soliton induced by negative background,the periodic travelling wave excited by the positive background,the few-cycle-pulse(FCP)solitons with and without background,the soliton molecules excited by the background.The FCP solitons are first obuained for the FOKdV equation.

Equivalent and Nonequivalent Barotropic Modes for Rotating Stratified Flows

All the possible equivalent barotropic (EB) laminar solutions are firstly explored,and all the possible non-EB elliptic circulations and hyperbolic laminar modes of rotating stratified fluids are discovered in this paper.The EB circulations (including the vortex streets and hurricane like vortices) possess rich structures,because either the arbitrary solutions of arbitrary nonlinear Poisson equations can be used or an arbitrary two-dimensional stream function is revealed which may be broadly applied in atmospheric and oceanic dynamics,plasma physics,astrophysics and so on.The discovery of the non-EB modes disproves a known conjecture.