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关键词： 股骨转子间骨折   内固定系统   力学稳定性   有限元分析   等效应力   压缩刚度  

摘要： 背景:股骨转子间骨折的骨折类型和固定方式多样,各固定系统间的力学稳定性相差较大。使用有限元分析方法对各固定系统开展生物力学研究具有科学的临床意义。目的:通过有限元方法对比分析多种内固定应用于股骨A031-A2.1型转子间骨折的力学稳定性。方法:在已验证有效性的股骨有限元模型基础上,对模型进行必要的切割,造模成股骨A031-A2.1型转子间骨折,模拟临床手术方法置入不同的内固定系统,分别建立股骨近端防旋髓内钉、动力髋螺钉、经皮加压钢板和股骨近端锁定钢板固定模型。约束4组模型股骨远端下所有节点,在股骨头上施加700,1400和2100N的压缩载荷,通过计算分析,观察各组模型的等效应力分布和压缩刚度,比较各组模型之间的力学稳定性。结果与结论:①通过计算分析,对比各组模型的变形量计算压缩刚度后,在各级载荷作用下,各组模型上压缩刚度呈现的趋势:生理组>股骨近端防旋髓内钉组>股骨近端锁定钢板组>经皮加压钢板组>动力髋螺钉组;完整的生理组模型的压缩刚度明显高于所有的手术组模型;②观察应力指标,因存在应力遮挡效应,致使各固定组的应力峰值均高于生理组,最大峰值均集中分布于各内固定上;其中股骨近端防旋髓内钉固定组应力峰值最小,动力髋螺钉固定组应力最高,应力分布趋势呈现:生理组<股骨近端防旋髓内钉固定组<经皮加压钢板固定组<股骨近端锁定钢板固定组<动力髋螺钉固定组;③分布于骨质模型的应力,因内固定置入位置不同呈现不同的分布结果;④提示对于股骨转子间骨折,各种内固定均能起到有效的固定,结合有限元分析结果得出股骨近端防旋髓内钉组是较好的一种内固定选择,呈现变形量小、应力峰值低,应力分布均匀的特性;经皮加压钢板组和股骨近端锁定钢板组的力学效果优良,固定效果接近股骨近端防旋髓内钉固定;动力髋螺钉固定效果欠佳,同比于其他内固定,其力学稳定性较差。

关键词： 山洪沟改道   高速公路   防洪安全   工程设计  

摘要： 山洪爆发极易诱发山洪沟泄洪通道两岸的泥石流、滑坡等灾害,而山区高速公路规划路线常常布置于山洪沟影响区,需要进行山洪沟泄洪通道改道。文章以四川某山区涉高速公路的山洪沟改道工程为例,以四川中小流域暴雨参数图集推求了该山洪沟的设计洪水,结合相应规范和标准给出了防洪标准和工程使用年限等,以及改道工程的布置。基于以上基础资料,通过水力学计算开展了改道的山洪沟横断面设计、消能防冲设计和冲沟设计等工作,并指出了在该改道工程管理中的注意事项。文章结合实际案例给出的山洪沟改道的设计流程与要点,可为类似道工程的设计提供借鉴与参考。

关键词： 卸污   设计   施工  

摘要： 深圳北站规模为11台20线,是铁路运营期间实施真空卸污补强比较复杂的大型枢纽站之一。本文对实施真空卸污系统补强的必要性、设计及施工要点进行分析和探讨,可为以后新建车站、运营车站技改工程的设计、施工提供借鉴和依据。

关键词： 规模化猪场   生物安全   车辆管理   车辆洗消   自动化监测  

摘要： 车辆管控与洗消是猪场生物安全体系的重要一环,对提高猪场的疫病防控能力至关重要。为了提高规模化猪场生物安全水平,本文以猪场的生物安全体系为出发点综述了规模化猪场的车辆管理与洗消要点,尤其是完备的猪场洗消系统通过多模块联动实现了病菌的高效杀灭,既能节约能耗,又能提高人员工作效率,应当大力推广与应用。

关键词： Erbium-doped fiber   Laser   Linear cavity   MATLAB   Narrow linewidth fiber laser   Saturable absorber  

摘要： Narrow linewidth fiber laser (NLFL) with linear cavity based on saturable absorber (SA) have made great progress, but there are few research reports on a pair of fiber Bragg gratings (FBG) as cavity mirrors and the simplification of their structures through automated design. We have demonstrated a simple compact linear cavity NLFL design based on SA and have developed an engineering model for automated design and optimization. Firstly, we have simulated the theoretical model to analyze the different lengths of SA and to determine their optimal lengths by MATLAB. Subsequently, we have constructed linear cavity laser with narrow-linewidth output and have performed comparative experiments using the different lengths of SA to validate the simulation results. Experimental results have shown that the optimal lasing output with a full width at half maximum (FWHM) of 0.0124 nm and an optical signal-to-noise ratio (OSNR) of 65.867 dB has been achieved when the length of SA is 2.05 m, which has been consistent with the MATLAB simulation results. Additionally, we have compared the effect of pump power on linewidth with or without the SA. The results have shown that the linewidth of the laser has been optimized at a specific pump power with the addition of the SA. We have also observed that the laser output is mainly affected by the bandwidth and center wavelength of the low-reflectivity fiber Bragg grating (LR-FBG) at room temperature.

关键词： MATLAB  

摘要： This paper addresses the critical problem of fault detection in DC zonal shipboard microgrids, which is essential for ensuring system reliability and operational safety. The proposed method detects faults by utilizing the high-frequency characteristics of estimated impedance. The technique involves Fast Fourier Transform analysis of current and voltage waveforms to extract high-frequency components before and after a fault. These features help identify the system's high-frequency impedance via a communication system. Fault detection is achieved by comparing the estimated impedance with a predefined threshold. The performance of the method is evaluated using MATLAB/Simulink simulations and experimental implementations under various scenarios. Communication between components in the DC zonal microgrid is managed using the IEC 61850 standard. Results demonstrate the method's effectiveness in detecting faults under diverse conditions, including variations in fault resistance, dynamic load behavior, changes in photovoltaic irradiation, system configuration alterations, noise immunity, and multi-fault scenarios. The method achieves fault clearance times ranging from 0.17 ms in MATLAB/Simulink simulations to 33–45 ms in experimental tests, showing its capability to enhance fault detection in complex DC microgrid environments. © 2024 The Authors

关键词： MATLAB  

摘要： The current research work is focused on thermal and mass transfer analysis on a hybrid nanofluid (water as a base fluid,) flow over a rotating disk with free convective, viscous dissipation, MHD, and radiation effects. The model was prepared in terms of the nonlinear PDEs and transformed into ODEs by using similarity analysis. Subsequently, it's solved numerically and graphically by ‘using the ‘bvp4c’ tool in MATLAB. The results depict that the fluid radial velocity can be enhanced by reducing the volume fraction of TiO2, and the azimuthal velocity of the disc is improved, due to nanoparticle TiO2 vol fraction and buoyancy force. Mass diffusion becomes low in the case of highly chemically reactive conditions. The flow characteristics are significantly influenced by variations in heat generation, thermal radiation, and MHD parameters. The calculated values of shear stress, Nusselt, and Sherwood numbers at the surface of the disk are also incorporated for complete verification. The deliberated model and graphical results have significant contributions in many fields like rotating machinery, lubricants, computer storage devices, viscometry, crystal growth process, etc. © 2025

关键词： MATLAB  

摘要： Peristalsis is the process of rhythmic, wave-like contractions in tubular structures that propel contents through them. A novel investigation of peristaltic flow in Ree-Eyring fluid with temperature-dependent properties is introduced in the study. The current research focuses on the peristaltic transport of non-Newtonian Ree-Eyring fluid in an axisymmetric non-uniform channel. A non-uniform channel with porous boundaries and inclination is considered in the study. Temperature-dependent variable fluid properties such as varying viscosity and thermal conductivity are considered. The Navier-Stokes equation and the Energy equations govern the fluid flow characteristics. Convective boundary conditions are employed at the boundary of the porous channel. The influence of chemical reactions, namely Homogeneous and Heterogeneous reactions, on the flow dynamics is considered in the study. The regular perturbation technique is employed to solve the non-linear coupled equations, and solutions for velocity, temperature, concentration, chemical reactions, and stream functions have been derived. Parametric analysis is implemented, and these variations are visually depicted through graphs generated by the MATLAB R2023a software. The results emphasise the substantial influence that variations in thermal conductivity and viscosity have on the properties of fluids. It has been noted that an increase in the Ree-Eyring fluid parameter reduces the velocity profiles. Also, the influence of porous and velocity slip parameters have the opposite impacts on the velocity profile. The study enhances the theoretical comprehension of non-Newtonian peristaltic flow and its practical implementations in industrial and biological systems, where variable fluid properties are essential. © 2025 The Author(s)

关键词： MATLAB  

摘要： This paper examines the throughput and outage performance of secondary users in a hybrid cognitive radio network (CRN) based on non-orthogonal multiple access (NOMA) technology. Based on channel occupancy, secondary transmitters in a hybrid CRN immediately switch between overlay or underlay mode in response to sensing results. If the primary user (PU) is not active, they operate in overlay mode with the maximum permitted transmit power else they operate in underlay mode with a transmit power restriction. The secondary network employs the NOMA approach, in which the base station (BS) is assisted by a full-duplex (FD) relay network to send information to the secondary destinations. Secondary transmitters are equipped with energy detector and harvesting circuit which allows to sense and store energy from the radio frequency (RF) of the multiple primary users. The benefit of using multiple FD relays along with the hybrid operation of joint mode transmission enables to increase the system throughput. Finally, an analytical formulation including closed form for the outage probability as encountered by the secondary users (SUs) in the presence of self interference (SI) and imperfect successive interference cancellation (i-SIC) under hybrid mode has been derived and validated through MATLAB simulation. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.

关键词： MATLAB  

摘要： Hydride-forming metal isotherms are complex due to the inherent multi-dimensional pressure–concentration–temperature dependencies. Hydrogen adsorbs to the surface of the hydride forming metal, then dissociating and diffusing into the metal. So doing boding with the metal, a further increase in pressure causes the hydride to undergo a change from low-pressure hydrides to high-pressure hydrides. Naturally, desorption is considered a reverse of the mechanism. These unique phenomena combined pose a challenge to modelling non-ideal gas-metal isotherms with hydrogen concentration as a function of pressure and temperature. This article reports the simulation of non-ideal hydride-forming metals, focusing on AB5-type hydride-forming metals. This was done as a numerical simulation in MATLAB, using a non-ideal gas-metal isotherm model, specifically Lototskyy’s model published in 2016, after which the simulations were experimentally validated. The semi-empirical non-ideal model requires numerical methods to solve, making a simulation key for the widespread use of the model. The numerical simulation produced can predict pressure–concentration–temperature isotherms with high accuracy. This study delivers a high-resolution, high-accuracy data set in the form of a simulation. This can then be used in further studies to accurately model metal hydride reactors for a variety of applications. © The Author(s) 2025.