Magneto-elastic combination resonances analysis of current-conducting thin plate

Based on the Maxwell equations, the nonlinear magneto-elastic vibration equations of a thin plate and the electrodynamic equations and expressions of electromagnetic forces are derived. In addition, the magneto-elastic combination resonances and stabilities of the thin beam-plate subjected to mechanical loadings in a constant transverse magnetic filed are studied. Using the Galerkin method, the corresponding nonlinear vibration differential equations are derived. The amplitude frequency response equation of the system in steady motion is obtained with the multiple scales method. The excitation condition of combination resonances is analyzed. Based on the Lyapunov stability theory, stabilities of steady solutions are analyzed, and critical conditions of stability are also obtained. By numerical calculation, curves of resonance-amplitudes changes with detuning parameters, excitation amplitudes and magnetic intensity in the first and the second order modality are obtained. Time history response plots, phase charts, the Poincare mapping charts and spectrum plots of vibrations are obtained. The effect of electro-magnetic and mechanical parameters for the stabilities of solutions and the bifurcation are further analyzed, Some complex dynamic performances such as perioddoubling motion and quasi-period motion are discussed.

Expert Experience and Data-Driven Based Hybrid Fault Diagnosis for High-SpeedWire Rod Finishing Mills

The reliable operation of high-speed wire rod finishing mills is crucial in the steel production enterprise.As complex system-level equipment,it is difficult for high-speed wire rod finishing mills to realize fault location and real-time monitoring.To solve the above problems,an expert experience and data-driven-based hybrid fault diagnosis method for high-speed wire rod finishing mills is proposed in this paper.First,based on its mechanical structure,time and frequency domain analysis are improved in fault feature extraction.The approach of combining virtual value,peak value with kurtosis value index,is adopted in time domain analysis.Speed adjustment and side frequency analysis are proposed in frequency domain analysis to obtain accurate component characteristic frequency and its corresponding sideband.Then,according to time and frequency domain characteristics,fault location based on expert experience is proposed to get an accurate fault result.Finally,the proposed method is implemented in the equipment intelligent diagnosis system.By taking an equipment fault on site,for example,the effectiveness of the proposed method is illustrated in the system.

Indirect neutron radiography experiment on dummy nuclear fuel rods for pressurized water reactors at CMRR

Nuclear energy is a vital source of clean energy that will continue to play an essential role in global energy production for future generations.Nuclear fuel rods are core components of nuclear power plants,and their safe utilization is paramount.Due to its inherent high radioactivity,indirect neutron radiography(INR)is currently the only viable technology for irradiated nuclear fuel rods in the field of energy production.This study explores the experimental technique of indirect neutron computed tomography(INCT)for radioactive samples.This project includes the development of indium and dysprosium conversion screens of different thicknesses and conducts resolution tests to assess their performance.Moreover,pressurized water reactor(PWR)dummy nuclear fuel rods have been fabricated by self-developing substitute materials for cores and outsourcing of mechanical processing.Experimental research on the INR is performed using the developed dummy nuclear fuel rods.The sparse reconstruction technique is used to reconstruct the INR results of 120 pairs of dummy nuclear fuel rods at different angles,achieving a resolution of 0.8 mm for defect detection using INCT.

Reliability analysis of carbon fiber rod-reinforced umbilical cable under tension using an improved sampling method

The umbilical cable is a vital component of subsea production systems that provide power,chemical agents,control signals et al.,and its requirement for reliability is exceedingly high.However,as the umbilical cable is a composite structure comprising multiple functional units,the reliability analysis of such cables involves numerous parameters that can impact calculation efficiency.In this paper,the reliability analysis of a new kind of umbilical cable with carbon fiber rod under tension is analyzed.The global dynamic analytical model is first established to determine the maximum tension load,then the local analytical model of umbilical cable including each unit are constructed by finite element method(FEM).Based on the mechanical analytical model,the reliability of umbilical cable under tension load is studied using response surface method(RSM)and Monte Carlo method.During the calculation process,a new tangent plane sampling method to calculate the response surface function(RSF)is proposed in this paper,which could make sampling points faster come close to the RSF curve,and it is proved that the calculation efficiency increases about 33%comparing with traditional method.

Numerical Analysis of Steady Smoldering of Biomass Rods

Understanding the steady mechanism of biomass smoldering plays a great role in the utilization of smoldering technology.In this study numerical analysis of steady smoldering of biomass rods was performed.A two-dimensional(2D)steady model taking into account both char oxidation and pyrolysis was developed on the basis of a calculated propagation velocity according to empirical correlation.The model was validated against the smoldering experiment of biomass rods under natural conditions,and the maximum error was smaller than 31%.Parameter sensitivity analysis found that propagation velocity decreases significantly while oxidation area and pyrolysis zone increase significantly with the increasing diameter of rod fuel.

Review of Computational Approaches to Optimization Problems in Inhomogeneous Rods and Plates

In this paper,we review computational approaches to optimization problems of inhomogeneous rods and plates.We consider both the optimization of eigenvalues and the localization of eigenfunctions.These problems are motivated by physical problems including the determination of the extremum of the fundamental vibration frequency and the localization of the vibration displacement.We demonstrate how an iterative rearrangement approach and a gradient descent approach with projection can successfully solve these optimization problems under different boundary conditions with different densities given.

Numerical Simulations of the Flow Field around a Cylindrical Lightning Rod

As an important lightning protection device in substations,lightning rods are susceptible to vibration and potential structural damage under wind loads.In order to understand their vibration mechanism,it is necessary to conduct flow analysis.In this study,numerical simulations of the flow field around a 330 kV cylindrical lightning rod with different diameters were performed using the SST k-ωmodel.The flow patterns in different segments of the lightning rod at the same reference wind speed(wind speed at a height of 10 m)and the flow patterns in the same segment at different reference wind speeds were investigated.The variations of lift coefficient,drag coefficient,and vorticity distribution were obtained.The results showed that vortex shedding phenomena occurred in all segments of the lightning rod,and the strength of vortex shedding increased with decreasing diameter.The vorticity magnitude and the root mean square magnitudes of the lift coefficient and drag coefficient also increased accordingly.The time history curves of the lift coefficient and drag coefficient on the surface of the lightning rod exhibited sinusoidal patterns with a single dominant frequency.For the same segment,as the wind speed increased in a certain range,the root mean square values of the lift coefficient and drag coefficient decreased,while their dominant frequencies increased.Moreover,there was a proportional relationship between the dominant frequencies of the lift coefficient and drag coefficient.The findings of this study can provide valuable insights for the refined design of lightning rods with similar structures.

连铸连轧铜杆生产线SCR法和Contirod法浅析

本文首先对当前主流的两种连铸连轧铜杆生产工艺进行简要阐述,其次对两款设备的不同之处进行较为详细的介绍,最后从多个方面阐述不同工艺对能耗指标和铜杆产品质量的影响。

应用Smiley face rod固定系统治疗L5椎弓峡部裂的疗效分析

目的 :探讨应用Smiley face rod固定系统治疗L5椎弓峡部裂的临床疗效。方法:2016年1月~2017年6月,我科采用Smiley face rod固定系统节段内固定植骨融合治疗腰椎峡部裂患者18例,男13例,女5例,年龄28.2±3.2岁(25~32岁),术前平均病程为16.3±5.7个月(7~24个月)。峡部裂节段均位于L5。术后3个月、1年时进行随访,对患者进行疼痛视觉模拟评分(visual analogue scale,VAS)及Oswestry功能障碍指数(Oswestry disability index,ODI)评定,评价其临床治疗效果。行X线、CT等检查,分析术前和术后L5/S1椎间活动度变化及椎间不稳发生率变化情况,并评价患者术后植骨融合情况。结果:手术时间平均90.0±24.1min,术中出血量平均140±15ml。平均随访18.5±5.0个月(12~24个月)。术前VAS评分为7.3±2.5分,ODI为(67.0±15.1)%;术后3个月时分别为3.0±1.2分和(17.2±4.5)%,较术前明显改善(P<0.05);术后1年时分别为1.0±0.6分和(9.1±5.3)%,较术后3个月时进一步改善(P<0.05)。术前L5/S1间隙活动度为13.1°±2.1°,存在腰椎不稳或小于Ⅰ度滑脱者共15例(83.3%,15/18);术后1年时分别为9.3°±1.6°和2例(11.1%,2/18),两者之间存在统计学差异(P<0.05)。术后1年时随访患者峡部裂均获得骨性愈合。结论 :应用Smiley face rod固定系统治疗L5椎弓峡部裂具有创伤小、对神经干扰少、恢复正常的解剖结构、提高椎间稳定性的优点。

Microstructures and mechanical properties of semi-solid squeeze casting ZL104 connecting rod

Semi-solid squeeze casting（SSSC） and liquid squeeze casting（LSC） processes were used to fabricate a ZL104 connecting rod, and the influences of the process parameters on the microstructures and mechanical properties were investigated. Results showed that the tensile strength and elongation of the SSSC-fabricated rod were improved by 22% and 17%, respectively, compared with those of the LSC-fabricated rod. For SSSC, the average particle size（APS） and the shape factor（SF） increased with the increase of re-melting temperature（Tr）, whereas the tensile strength and elongation increased first and then decreased. The APS increased with increasing the mold temperature（Tm）, whereas the SF increased initially and then decreased, which caused the tensile strength and elongation to increase initially and then decrease. The APS decreased and the SF increased as squeezing pressure（ps） increased, and the mechanical properties were enhanced. Moreover, the optimal Tr, ps and Tm are 848 K, 100 MPa and 523 K, respectively.

Wiltse入路与后正中入路非融合K-Rod内固定术治疗腰椎间盘突出症比较研究

腰椎是躯体发生退行性病变最早的部位,腰椎间盘突出症患者表现为下腰椎不稳,腰背部及下肢疼痛等,严重影响生活质量[1-2].手术是常用的治疗方法,后正中入路从中线部分贴棘突及椎板骨面剥离双侧椎旁肌肉软组织,暴露小关节突至横突[3],是一直沿用的传统入路.Wiltse入路是利用多裂肌与最长肌间隙,无需大范围剥离椎旁肌,可减少多裂肌损伤,保留棘突上肌肉及韧带的附着点.本研究比较腰椎间盘突出症患者采用Wiltse入路与后正中入路两种入路行非融合K-Rod内固定术的效果,旨在为类似病例手术入路的选择提供参考,报告如下.

K-Rod的临床应用

目的探讨K-Rod治疗腰椎间盘突出症和腰椎管狭窄的短期疗效。方法 2010年12月～2011年4月,采用K-Rod共治28例腰椎间盘突出症和腰椎管狭窄患者。L3/4者2例;L4.5者3例;L5S1者15例;L4.5L5S1双节段8例。男12例,女16例;年龄38～70岁,平均53.5岁。随访12～16个月,通过VAS评分、ODI指数和影像学分析评价其疗效。结果患者VAS评分、Oswestry功能障碍指数(ODI)均获得显著改善(P<0.05);患者术后,术后6个月及末次随访时,手术节段椎间高度差异无显著变化,置入节段及邻近节段椎间活动范围差异无显著性意义。结论 K-Rod是治疗腰椎间盘突出症和腰椎管狭窄的一种有效方法,远期效果待进一步观察。

Rod-pinch二极管箍缩特性的数值模拟

采用UNIPIC程序模拟Rod-pinch二极管(RPD)的工作过程,重点研究阳极等离子体和二极管结构参数对电子束箍缩的影响。模拟结果表明,在不考虑阳极离子流作用情况下,RPD无法在较低电压下(<2MV)实现箍缩;当阳极离子流达到一定值后,进一步增加阳极表面发射离子流密度对二极管总电流和阳极杆尖端电流密度影响很小;阴极不同表面发射电子束的箍缩效果不同,各表面同时发射电子时,后表面发射的电子束箍缩效果最好,其次是中间表面,前表面最差;增大阴极厚度不能显著缩短电子束实现箍缩的时间。给出了阳极杆伸出阴极平面距离和阴阳极半径比等参数的选取范围,对模拟计算与实验结果间的偏差作出了解释。

K-Rod脊柱动态稳定系统在多节段腰椎退行性疾病中的临床应用

目的 ：评估K-Rod脊柱动态稳定系统治疗多节段腰椎退行性疾病的临床疗效。方法 ：2011年10月至2013年10月应用K-Rod脊柱动态稳定系统治疗多节段腰椎退行性疾病20例,男8例,女12例;年龄31-65岁,平均45.4岁;病程9个月-6.25年,平均3.8年。所有患者术前有腰腿痛病史,其中极外侧腰椎间盘突出症10例,腰椎管狭窄症7例,腰椎滑脱3例（Ⅰ度滑脱2例,Ⅱ度滑脱1例）,所有病例的责任节段为单节段,并且责任间隙的相邻椎间盘至少有1节已经出现明显退变。进行手术解除神经压迫及植入K-Rod脊柱后路动态稳定系统（其中责任间隙行椎间融合,退变邻椎行动态稳定）。采用疼痛视觉模拟评分（VAS）、日本矫形外科协会关于下腰痛的评分标准（JOA）和Oswestry功能障碍指数（ODI）评估临床疗效;通过影像学资料对退变邻椎节段活动度（ROM）、椎间盘高度及椎间盘信号（根据改良Pfirrmann分级系统）进行评估。结果：全部患者获得1年以上随访,术前症状均明显缓解,腰腿痛VAS、JOA及ODI术前与术后1周、术后1年差异均有统计学意义（P〈0.05）。术后影像学检查见责任节段均已融合,未见内植物松动、移位及断裂。术后相邻椎间盘的ROM有所减少（P〈0.05）。相邻退变椎间盘的高度术后1年与术前比较差异无统计学意义（P〉0.05）。对25个相邻椎间盘应用改良Pfirrmann分级系统进行分级并对比,术后1年共有8个（32%）椎间盘在评级中有所好转,15个（60%）椎间盘在评级中无变化,2个（8%）椎间盘在评级中退变加重。结论：应用腰椎融合辅以邻近节段动态固定的K-Rod脊柱动态稳定系统治疗多节段腰椎退行性疾病,可以取得良好的近期临床疗效。

离子对rod-pinch二极管工作特性的影响

利用PIC粒子模拟方法,结合对同轴结构二极管工作模式的半解析描述,研究了离子存在与否对rod-pinch二极管(RPD)工作特性的影响。模拟给出了二极管的伏安特性、不同时刻电子和离子的相空间分布以及空间电流分布等。结果表明随着电流逐渐增大,其工作模式从空间电荷限制流依次向弱箍缩流和磁绝缘流转变。只有存在离子的情况下,电子才能沿着阳极杆表面运动并在其末端发生箍缩,表明RPD中离子电流的存在对于RPD工作是必需的。

Rod-pinch二极管理论及数值模拟

介绍了Rod-pinch二极管的基本结构和工作原理,采用Laminar模型分析了Rod-pinch二极管中的粒子运动过程及其阻抗特性。考虑背景空间离子电荷的影响,用1维Laminar方程分析Rod-pinch二极管中电子的自箍缩过程,并且利用Magic程序对其中的粒子运动进行数值模拟,求解二极管中的电压和电流,最终得出二极管的阻抗特性,在较低电压下,负极性RPD的性能明显不如正极性RPD。根据临界电流经验公式,初步验证Laminar理论模型的可行性。

周期性Rod方程的一个新的爆破条件

首先,通过应用Fourier级数展开的方法,为一类Sobolev嵌入不等式找到了最佳常数.该方法比以往常用的变分法更简单、直接.然后,用已有的不等式为周期性的弹性力杆方程建立了一个新的爆破条件.

A Method for Forecasting Failures of Sucker Rod-pumped Wells

An exact forecast of the failures of a sucker rod-pumped well in a production area means much for an oilfield’s operation budget, operational arrangement and production plan. In this paper, according to the characteristics of failed sucker rod-pumped well randomness and strong outburst, with the gray GM (1,1) forecast model and the Markov forecast model combined, gray GM (1,1) forecast model is utilized to handle the primary data of an oilfield, and Markov forecast model is utilized to calculate the state transfer probability of forecast value. Then, the gray Markov forecast model considering the influence of randomness factors is formed. Field results prove that the calculation precision of this method is higher and the practicability is greater.

马氏杆(Maddox rod)检查方法图解

马氏杆由一系列的平行的柱镜组成。被检查者双眼注视远处点状光源,此时在一只眼前放置马氏杆,就使该眼前点光源变成直线;而另一只眼前未放置马氏杆所见的点状光源仍为点状,从而使双眼所见物像不同。马氏杆观察眼前的点状光源就变成一条线状光,并且此条线状光的方向与组成马氏杆的柱镜长轴方向是互相垂直的。采用马氏杆加三棱镜检查出的斜视度数（包括隐斜和显斜两部分）。

K-Rod动态稳定系统治疗腰椎退行性疾病的中期疗效

目的探讨K-Rod动态稳定系统治疗腰椎退行性疾病的中期疗效及其对邻近上位节段的影响。方法回顾性分析昆明市第一人民医院骨科2011年2月至2013年6月65例采用K-Rod动态稳定系统治疗腰椎退行性疾病患者的临床资料。其中,男31例,女34例,年龄21~73岁,平均(53.4±10.8)岁;融合组(n=21),非融合组(n=20),“融合+非融合”组(n=24)。记录术中失血量、手术时间、住院时间及并发症;根据术前及各随访时间腰痛、下肢痛VAS评分,ODI评分评价临床疗效。比较3组病例术前及随访时间腰椎侧位X线片、腰椎MRI手术及邻近上位节段椎间隙高度、椎间盘退变Pfirrmann's分级情况。结果经72~84个月,平均(72.0±8.6)个月随访。3组组内术后3、6个月及末次随访时腰痛、下肢痛VAS评分及ODI评分与术前比较,差异均有统计学意义(P<0.05)。末次随访时,腰痛、下肢痛VAS评分改善率,融合组为66.4%、76.7%,非融合组为84.4%、72.4%,“融合+非融合”组为70.8%、77.8%;邻近上位节段椎间盘退变Pfirrmann's分级:非融合组、“融合+非融合”组与术前比较差异无统计学意义(P>0.05),融合组与术前比较差异有统计学意义(P<0.05)。手术节段椎间高度指数:3组组内术后1周与术前比较,差异有统计学意义(P<0.05),术后3个月、6个月、末次随访时与术后1周比较差异无统计学意义(P>0.05)。邻近节段椎间高度指数:非融合组、“融合+非融合”组术后1周、3个月、6个月、末次随访时与术前比较,差异无统计学意义(P>0.05);融合组末次随访与术前比较,差异有统计学意义(P<0.05)。结论应用K-Rod动态稳定系统对腰椎退行性疾病行非融合及“非融合+融合”术治疗,中期随访疗效良好,一定程度上可延缓邻近节段椎间盘退变,对退变的椎间盘有一定的保护作用。