Numerical simulation of recalescence of 3-dimensional isothermal solidification for binary alloy using phase-field approach

A accelerated arithmetic algorithm of the dynamic computing regions was designed,and 3-dimensional numerical simulation of isothermal solidification for a binary alloy was implemented.The dendritic growth and the recalescence of Ni-Cu binary alloy during the solidification at different cooling rates were investigated.The effects of cooling rate on dendritic patterns and microsegregation patterns were studied.The computed results indicate that,with the increment of the cooling rate,the dendritic growth velocity increases,both the main branch and side-branches become slender,the secondary dendrite arm spacing becomes smaller,the inadequate solute diffusion in solid aggravates,and the severity of microsegregation ahead of interface aggravates.At a higher cooling rate,the binary alloy presents recalescence;while the cooling rate is small,no recalescence occurs.

Fractional-dimensional approach for excitons in Ga As films on AlxGa(1-x)As substrates

Binding energies of excitons in GaAs films on AlxGal-xAs substrates are studied theoretically with the fractional- dimensional approach. In this approach, the real anisotropic ＂exciton ＋ film＂ semiconductor system is mapped into an effective fractional-dimensional isotropic space. For different aluminum concentrations and substrate thicknesses, the exci- ton binding energies are obtained as a function of the film thickness. The numerical results show that, for different aluminum concentrations and substrate thicknesses, the exciton binding energies in GaAs films on AlxGal_xAs substrates all exhibit their maxima with increasing film thickness. It is also shown that the binding energies of heavy-hole and light-hole excitons both have their maxima with increasing film thickness.

Three-dimensional hydrodynamic model of Xiamen waters

A semi-implicit and Eulerian - Lagrangian finite difference method for three-dimensionalshallow flow has been extended to a more complete system of equations incorporating second-moment turbulence closure model and transport equations of salinity and temperature. The simulation for flooding and drying of mudflats has been improved. The model is applied to Xiamen waters. Based on extensive survey data, water level elevation, temperature and salinity field along the eastern open boundary and at the Jiulong River inlets and runoffs are analyzed, specified and calibrated. The computed results show good agreement with the measured data, reproduce flooding, emergence of large and complex mudflat region.

New periodic wave solutions, localized excitations and their interaction for (2+1)-dimensional Burgers equation

Based on the B/icklund method and the multilinear variable separation approach （MLVSA）, this paper finds a general solution including two arbitrary functions for the （2＋1）-dimensional Burgers equations. Then a class of new doubly periodic wave solutions for （2＋l）-dimensional Burgers equations is obtained by introducing appropriate Jacobi elliptic functions, Weierstrass elliptic functions and their combination in the general solutions （which contains two arbitrary functions）. Two types of limit cases are considered. Firstly, taking one of the moduli to be unity and the other zero, it obtains particular wave （called semi-localized） patterns, which is periodic in one direction, but localized in the other direction. Secondly, if both moduli are tending to 1 as a limit, it derives some novel localized excitations （two-dromion solution）.

Goodness-of-fit tests for multi-dimensional copulas:Expanding application to historical drought data

The question of how to choose a copula model that best fits a given dataset is a predominant limitation of the copula approach, and the present study aims to investigate the techniques of goodness-of-fit tests for multi-dimensional copulas. A goodness-of-fit test based on Rosenblatt＇s transformation was mathematically expanded from two dimensions to three dimensions and procedures of a bootstrap version of the test were provided. Through stochastic copula simulation, an empirical application of historical drought data at the Lintong Gauge Station shows that the goodness-of-fit tests perform well, revealing that both trivariate Gaussian and Student t copulas are acceptable for modeling the dependence structures of the observed drought duration, severity, and peak. The goodness-of-fit tests for multi-dimensional copulas can provide further support and help a lot in the potential applications of a wider range of copulas to describe the associations of correlated hydrological variables. However, for the application of copulas with the number of dimensions larger than three, more complicated computational efforts as well as exploration and parameterization of corresponding copulas are required.

Symmetry and Similarity Solutions of a （2＋1）-Dimensional Generalized Broer-Kaup System

We study the symmetries of a （2＋1）-dimensional generalized Broer-Kaup system by means of the classical Lie group theory. The corresponding group algebra is constructed. Based on the symmetries, severaJ types of similarity solutions are obtained.

New Exact Traveling Wave Solutions of (2 + 1)-Dimensional Time-Fractional Zoomeron Equation

In this paper, the new mapping approach and the new extended auxiliary equation approach were used to investigate the exact traveling wave solutions of (2 + 1)-dimensional time-fractional Zoomeron equation with the conformable fractional derivative. As a result, the singular soliton solutions, kink and anti-kink soliton solutions, periodic function soliton solutions, Jacobi elliptic function solutions and hyperbolic function solutions of (2 + 1)-dimensional time-fractional Zoomeron equation were obtained. Finally, the 3D and 2D graphs of some solutions were drawn by setting the suitable values of parameters with Maple, and analyze the dynamic behaviors of the solutions.

The Impact of Religious Dimension on Entrepreneurial Intention by Using PLS Approach --Case Study

In a complex environment resulted from the economic and technological changes, and the emergence of the uncertainty cases, the entrepreneurial thought knows a development in the determinants of entrepreneurial spirit, that has become a mechanism and a dynamic of the competitivety of international economies, starting by the construction of investment projects whether individual or collective, which are based on innovation and the use of technology as factors that have the ability to give business competitiveness and increase its economic efficiency, also that is through the creation of job opportunities and reaching the economic development. This research aims to study the effect of the religious dimension and the dimensions of entrepreneurial behavior on the entrepreneurial intention among youth who are interested in realizing entrepreneurial projects. The partial least squares approach （PLS） has been used in this study and it results that the religious dimension influences positively the entrepreneurial intention.

Three-dimensional elasticity solutions for bending of generally supported thick functionally graded plates

Three-dimensional elasticity solutions for static bending of thick functionally graded plates are presented using a hybrid semi-analytical approach-the state-space based differential quadrature method （SSDQM）. The plate is generally supported at four edges for which the two-way differential quadrature method is used to solve the in-plane variations of the stress and displacement fields numerically. An approximate laminate model （ALM） is exploited to reduce the inhomogeneous plate into a multi-layered laminate, thus applying the state space method to solve analytically in the thickness direction. Both the convergence properties of SSDQM and ALM are examined. The SSDQM is validated by comparing the numerical results with the exact solutions reported in the literature. As an example, the Mori-Tanaka model is used to predict the effective bulk and shear moduli. Effects of gradient index and aspect ratios on the bending behavior of functionally graded thick plates are investigated.

Variable separation solutions and new solitary wave structures to the （l＋l）-dimensional Ito system

A variable separation approach is proposed and extended to the （1＋1）-dimensional physics system. The variable separation solution of （1-F1）-dimensional Ito system is obtained. Some special types of solutions such as non-propagating solitary wave solution, propagating solitary wave solution and looped soliton solution are found by selecting the arbitrary function appropriately.

Algebraic Calculation Method of One-Dimensional Steady Compressible Gas Flow

This paper describes a new method of calculation of one-dimensional steady compressible gas flows in channels with possible heat and mass exchange through perforated sidewalls. The channel is divided into small elements of a finite size for which mass, energy and momentum conservation laws are written in the integral form, assuming linear distribution of the parameters along the length. As a result, the calculation is reduced to finding the roots of a quadratic algebraic equation, thus providing an alternative to numerical methods based on differential equations. The advantage of this method is its high tolerance to coarse discretization of the calculation area as well as its good applicability for transonic flow calculations.

Three-dimensional Analysis of Functionally Graded Piezoelectric Plate with Arbitrarily Distributed Material Properties

An orthotropic functionally graded piezoelectric rectangular plate with arbitrarily distributed material properties was studied, which is simply supported and grounded（electrically） on its four lateral edges. The state equations of the functionally graded piezoelectric material were obtained using the state-space approach, and a Peano-Baker series solution was obtained for the coupled electroelastic fi elds of the functionally graded piezoelectric plate subjected to mechanical and electric loading on its upper and lower surfaces. The influence of different distributions of material properties on the structural response of the plate was studied using the obtained solutions.

基坑开挖引起下穿交叉隧道变形效应分析

以某地铁站换乘大厅工程为例,利用FLAC 3D数值模拟软件,分析总结了上跨深大基坑开挖对不同空间距离和分布形式的下穿立体交叉隧道的变形影响规律,并结合现场监测数据与数值模拟结果进行相互验证,结果表明:(1)基坑开挖卸荷对下穿隧道结构变形的影响主要表现为竖向位移,其变形量与基坑的空间位置和基坑岩土体开挖卸荷量密切相关;(2)1号线左、右线隧道全施工周期监测数据与数值模拟结果吻合较好,验证了数值计算方法对施工活动影响判断的准确性;(3)多种应力状态耦合的叠落隧道竖向位移受叠加效应影响显著,最大竖向位移位于影响因素较多的区域,最大竖向位移值为34.84 mm;(4)埋深较浅隧道对施工扰动比深埋隧道更加敏感,不同位置处的变形离散性更强,变形具有一定的整体性和协同性。

基于二维云模型的进近管制系统安全风险评估

进近管制系统的安全运行是确保民航运输安全的关键。安全风险评估是风险管理的基础,其可以提升安全风险管理效率,提高系统整体运行的安全性。同时考虑安全风险因素和安全风险事件,从管制员风险、设备风险、气象环境风险、管制环境风险和管理风险等5大方面建立进近管制系统安全风险评估指标体系;通过二维云模型得到某进近管制系统的安全风险等级为Ⅲ级并与一维云模型对比,证明评估模型具有有效性。将组合赋权的方法与改进的层次分析法和CRITIC法作对比分析,结果表明:组合赋权的方法不仅减少了主观随意性,还中和了主客观权重的不足;使用组合赋权-二维云模型进行进近管制系统安全风险评估结果更加准确。

3D打印技术用于经鼻蝶窦入路垂体腺瘤切除术应用效果及对血清MMP-9和IGF-1水平的影响

目的:探究3D打印技术在经鼻蝶窦入路垂体腺瘤(PA)切除术的应用效果及对血清基质金属蛋白酶-9(MMP-9)和胰岛素样生长因子-1(IGF-1)水平的影响。方法:选取2020年5月至2022年5月秦皇岛市第一医院收治的84例PA患者,按照随机数表法将其分为观察组和对照组,每组42例。对照组行经鼻蝶窦入路垂体腺瘤切除术,观察组行经鼻蝶窦入路垂体腺瘤切除术联合应用3D打印技术,比较两组肿瘤切除效果、围术期指标、视力改善情况、MMP-9和IGF-1水平,以及鼻腔功能的鼻气道阻力(NAR)、T&T嗅觉测试评分及并发症。结果:观察组肿瘤切除效果优于对照组,差异有统计学意义(U=2.286,P<0.05);观察组手术时间、术中出血量及住院时间均少于对照组,差异有统计学意义(t=4.780、11.438、11.842,P<0.05);术后3 d、7 d时观察组血清MMP-9和IGF-1水平低于对照组,差异有统计学意义(F=7.526、4.985,P<0.05);术后1个月、3个月时观察组NAR及T&T嗅觉测试评分低于对照组,差异有统计学意义(F=6.359、8.436,P<0.05);两组视力视野改善情况及并发症发生率比较,差异无统计学意义(P>0.05)。结论:3D打印技术用于经鼻蝶窦入路垂体腺瘤切除术可提高肿瘤切除效果,优化手术操作,减少创伤,有利于减轻疼痛,改善嗅觉功能与视力视野,并能降低血清MMP-9、IGF-1水平,且安全性较高。

数字化技术在经颏下前庭入路腔镜甲状腺手术中的应用

目的:探讨三维数字化技术在经颏下前庭入路腔镜甲状腺手术中的应用价值。方法:将2022年1月1日至2023年12月31日经术前细胞学诊断明确为甲状腺乳头状癌的60例患者随机分为数字化组(n=30)与常规手术组(n=30),数字化组经颏下前庭入路行腔镜甲状腺手术联合三维数字化模型制作,常规手术组仅行经颏下前庭入路腔镜甲状腺手术。比较两组术前与患者沟通时间、术中出血量、手术时间、术后并发症等相关指标。结果:两组手术均获成功,数字化组与常规手术组术前与患者沟通时间[(21.83±4.83)min vs.(32.07±6.61)min]、手术时间[(112.03±8.33)min vs.(138.01±13.29)min]、术中出血量[(13.63±3.81)mL vs.(19.17±4.51)mL]差异有统计学意义(P<0.05)。两组术后并发症差异无统计学意义(P>0.05)。结论:三维数字化技术的应用可提高医患沟通效率,减少术中出血量,缩短手术时间,提高腔镜甲状腺手术的安全性,值得推广应用。

3D打印技术辅助改良跗骨窦入路内固定治疗跟骨骨折的疗效

目的 探讨3D打印技术辅助改良跗骨窦入路内固定治疗跟骨骨折的疗效。方法 按是否行3D打印技术辅助将57例跟骨骨折患者分为3D打印组(采用3D打印技术辅助改良跗骨窦入路内固定治疗,30例)和常规组(采用单纯改良跗骨窦入路内固定治疗,27例)。记录两组手术指标、骨折愈合情况、疼痛VAS评分、AOFAS踝-后足评分、影像学指标(B9hler角、Gissane角)、术后并发症发生率。结果 患者均获得随访,时间6~12个月。术中出血量、术中透视次数、手术时间、住院时间:3D打印组均少(短)于常规组(P<0.01)。两组骨痂形成时间6~8周,骨折愈合时间12~18周。术后、末次随访时影像学指标:两组均大于术前(P<0.01);3D打印组均大于常规组(P<0.05)。术后第1、2、3天疼痛VAS评分、术后并发症发生率:3D打印组均低于常规组(P<0.05)。末次随访时AOFAS踝-后足评分及其优良率:3D打印组均高于常规组(P<0.05)。结论 3D打印技术辅助改良跗骨窦入路内固定治疗跟骨骨折,能够缩短手术时间及住院时间,减少术中出血量及透视次数,尽快恢复跟骨解剖结构,同时能明显减轻患者术后疼痛,改善患足功能,减少并发症的发生。

党的二十大精神融入高校思政课“四维一体”立体教学路径探析

党的二十大报告高屋建瓴,系统概括了新时代十年的伟大成就,总结了新时代中国特色社会主义的重大成果,指明了党和国家事业的前进方向,具有丰富的育人元素和育人价值。高校思想政治理论课的课程属性、教学内容及育人目标的实现,迫切要求把党的二十大精神及时有效融入课程教学。高校思政课教师作为课程教学的“第一责任人”,如何推进党的二十大精神及时有效融入课程教学?是当前亟待探讨和解决的热点问题。高校思政课教师应当立足三尺讲台,结合教育教学实际,对党的二十大精神融入高校思政课的具体环节进行研究分析,依托构建“四维一体”立体教学路径,着力解答“如何有效融入”的问题。

基于项目驱动的高职思政课程立体化实践教学模式研究

针对当前高职思政课实践教学面临的学生参与积极性不高、教学方法亲和力不足、教学内容针对性不强、教学平台融合度不足、教学评价反馈度不够等问题,进行思政课教学模式探索并提出基于项目驱动的高职思政课立体化实践教学模式,总结高职思政课实践教学的改进建议,实践证明该模式整体上提升了学校的办学水平和质量,提高了教师的思政课实践教学能力和学生的思政综合素养。

Analysis on Grammar Teaching Mode in Current Chinese University Based on Freeman's Three Dimension Theory

it is universal acknowledgement that grammar takes an indispensable place in English learning yet increasing evidences show that there are still serious problems exists in China grammar teaching:low learning motivation,goal-oriented teaching mode and traditional deductive approach.Freeman’s Three Dimension Theory(1991)suggests that grammar should be understood as three respective:form,meaning,usage.This thesis analyses the dominant deficiencies which reveals traditional teaching mode only lays emphasis on form or meaning.Neglecting on importance of context obscures mastery of grammar rules by students.By the end of this paper,taking teaching of conditionals as examples,a suggestive teaching model is provided based on Three Dimension Theory(Freeman,1991).