Short Stroke Control with Gaussian Curve and PSO Algorithm in Plate Rolling Process

The precision width control is vital for product quality and production economy in plate width control process,so short stroke control method was used in plate rolling by opening or closing edger gap so as to avoid head end necking.Head end necking on different broadening ratio was analyzed,and sections of different elongations at edger rolling was calculated;based on the law of volume constancy,the adjustment functions were described by parabolic functions.Control curves were developed with three Gaussian curves by means of additional combining;SSC control curve was changed with different weights of those curves,w_1effect one-third of SSC length,w_2effect two-third of SSC length,w_3effect all three parts of SSC length.In order to adjust the amount of weights for precise quantification,PSO algorithm was used to build sufficiency function so as to obtain best rectangular degree by global optimization.Practical applications showed that the method proposed is available to improve the product rolling yields by 1.0%-2.0%and worthy to apply to plate rolling.

Short-Term Kinematics of the Adria Plate and Space-Time Distribution of Major Peri-Adriatic Earthquakes

Seismic activity is quite strong in the peri-Adriatic zones, whereas the internal part of the Adria plate is almost aseismic. This pattern suggests that Adria is a solid block that interacts with the surrounding belts, trying to move roughly northward. Each major earthquake in a peri-Adriatic zone triggers the acceleration of the decoupled Adria sector, which induces a perturbation of the stress/strain fields in the still blocked boundaries of the plate. Step by step, the displacement of Adria involves more and more northern zones to finally reach the northern front of the plate (eastern Southern Alps). This interpretation seems to be compatible with the time patterns of seismic activity in the main peri-Adriatic zones since 1600 A.D., which may suggest repeated northward migrations of seismic crises. Each supposed migrating sequence involves major earthquakes in most zones. The main features of the first 4 seismic sequences (1600-1930) are used to get insights into possible regularities in the progressive activations of the peri-Adriatic zones. This information and the main features of the ongoing migrating sequence (since 1931) are then used to tentatively recognize the peri-Adriatic zones where the occurrence of next major earthquakes may be most likely.

Volar locking distal radius plates show better short-term results than other treatment options: A prospective randomised controlled trial

AIM To compare the outcomes of displaced distal radius fractures treated with volar locking plates and with immediate postoperative mobilisation with the outcomes of these fractures treated with modalities that necessitate 6 wk wrist immobilisation.METHODS A prospective, randomised controlled single-centre trial was conducted with 56 patients who had a displaced radius fracture were randomised to treatment either with a volar locking plate(n = 29), or another treatment modality(n = 27; cast immobilisation with or without wires or external fixator). Outcomes were measured at 12 wk. Functional outcome scores measured were the Patient-Rated Wrist Evaluation(PRWE) Score; Disabilities of the Arm, Shoulder and Hand and activities of daily living(ADLs). Clinical outcomes were wrist range of motion and grip strength. Radiographic parameters were volar inclination and ulnar variance.RESULTS Patients in the volar locking plate group had significantly better PRWE scores, ADL scores, grip strength and range of extension at three months compared with the control group. All radiological parameters were significantly better in the volar locking plate group at 3 mo. CONCLUSION The present study suggests that volar locking plates produced significantly better functional and clinical outcomes at 3 mo compared with other treatment modalities. Anatomical reduction was significantly more likely to be preserved in the plating group. Level of evidence: Ⅱ.

带短肋钢筋桁架预制底板受弯性能研究

为研究带短肋钢筋桁架预制底板的力学性能,采用ABAQUS建立有限元模型,对比了该板与钢筋桁架预制底板的受弯性能,探讨了短肋形式对该板受弯性能的影响,分析了短肋长度、宽度、数量等因素对该板受弯性能的影响。结果表明:与钢筋桁架预制底板相比,带短肋钢筋桁架预制底板的承载力和刚度更高,带短肋钢筋桁架预制底板具有可行性;矩形短肋可有效提高该板的承载力和刚度;短肋长度、宽度对该板受弯性能影响较大,最大相差21.73%,且短肋长度主要影响承载力,宽度主要影响刚度;短肋混凝土强度等级、厚度,数量对该板受弯性能影响较小,最大相差3.5%。

窄间距静电除尘分离细颗粒物综合实验设计

细颗粒物分离是环境工程教学的核心内容,为提升“大气污染控制工程实验”、“环境工程综合实验”等课程“两性一度”教学水平,将室内细颗粒物污染特征及其分离技术等公众关注的热点问题引入实验教学。利用自制窄间距静电教学实验系统,模拟发生不同粒径范围、数目浓度和质量浓度的细颗粒物,通过改变静电分离组件、电极配置、电场风速和供电电压等参数,综合评价窄间距静电除尘实验系统分离细颗粒物的效能,实验内容可拓展到餐饮油烟特征细颗粒物等应用场景。实验不仅提升学生实验操作能力,也通过不同难度等级的实验设置,分层次培养学生高阶性思维,激发学生实验热情,对提高本科生培养质量具有重要意义。

碳纤维表面处理对铜基摩擦材料性能的影响

采用粉末冶金技术制备了添加短切碳纤维的铜基摩擦材料,研究了碳纤维粗化、碳纤维镀铜对铜基摩擦材料组织、力学性能及摩擦磨损性能的影响。结果表明:由于碳纤维与铜基体界面性能较差,添加无处理碳纤维后,摩擦材料的硬度及密度最低,摩擦系数和磨损率在不同制动初速度下最大。添加粗化处理碳纤维的摩擦材料,其摩擦系数低于未添加碳纤维的,硬度及密度有所降低。由于碳纤维镀铜改善了碳纤维与基体之间的润湿性与结合状态,硬度以及密度有轻微下降。碳纤维发挥了其固体润滑剂的作用,摩擦系数稳定,碳纤维镀铜处理试样的磨损量最低。

SE短槽式干挂陶土板施工技术

北京市房山区青龙湖综合性商业金融服务项目使用了SE短槽式干挂陶土板施工技术,成功实现了幕墙装饰板材的工厂化加工、现场干挂式安装,起到了提高工作效率、增加外观装饰美感、降低工程成本的良好效果。

微型断路器灭弧系统对短路分断能力影响的研究

短路分断能力是微型断路器(MCB)的一项重要的技术指标,影响该指标的因素很多。通过对分断试验样机烧蚀的情况——动触头引弧板顶部电弧停滞时间长、烧蚀严重及灭弧栅片未被有效利用进行分析,结合理论提出优化方案并进行试验验证,得出优化引弧板设计、灭弧室设计以及出气口结构有利于缩短电弧停滞时间,加快电弧的引弧速度,提高栅片切弧利用率,以增加电弧电压,进而提高MCB的分断性能。

An Improved Adaptive Exponential Smoothing Model for Short-term Travel Time Forecasting of Urban Arterial Street

旅行时间的短期的预报为聪明的交通系统的成功是必要的。在这份报纸，我们考察预报模型的短期的交通的 state-of-art 并且构画出他们每个模型的基本想法，相关工作，优点和劣势。一改进适应指数的变光滑(IAES ) 模型也被建议克服以前的适应指数的变光滑模型的缺点。然后，比较实验在状况和反常交通调节评估在牌照匹配获得的直接旅行时间数据(每分钟行数) 上预报模型的四个主要分支的性能的正常交通下面被执行。实验的结果证明每个模型似乎有它的自己的力量和软弱。IASE 的预报表演比在更突然预报地平线(预报的和二步) 的另外的模型优异， IASE 能够处理各种交通条件。

Quantitative Rectangular Notch Detection of Laser-induced Lamb Waves in Aluminium Plates with Wavenumber Analysis

It is difficult to quantitatively detect defects by using the time domain or frequency domain features of Lamb wave signals due to their dispersion and multimodal characteristics.Therefore,it is important to discover an intrinsical parameter of Lamb waves that could be used as a damage sensitive feature.In this paper,quantitative defect detection in aluminium plates is carried out by means of wavenumber analysis approach.The wavenumber of excited Lamb wave mode is a fixed value,given a frequency,a thickness and material properties of the target plate.When Lamb waves propagate to the structural discontinuity,new wavenumber components are created by abrupt wavefield change.The new wavenumber components can be identified in the frequency-wavenumber domain.To estimate spatially dependent wavenumber values,a short-space two-dimensional Fourier transform(FT)method is presented for processing wavefield data of Lamb waves.The results can be used to determine the location,size and depth of rectangular notch.The analysis techniques are demonstrated using simulation examples of an aluminium plate with a rectangular notch.Then,the wavenumber analysis method is applied to simulation data that are obtained through a range of notch depths and widths.The results are analyzed and rules of the technique with regards to estimating notch depth are determined.Based on simulation results,guidelines for using the technique are developed.Finally,experimental wavefield data are obtained in aluminium plates with rectangular notches by a full noncontact transceiving method,i.e.,laser-laser method.Band-pass filtering combined with continuous wavelet transform is used to extract a certain frequency component from the full laser-induced wavefield with wide band.Shortspace two-dimensional FT method is used for further processing full wavefield data at a certain frequency to estimate spatially dependent wavenumber values.The consistency of simulation and experimental results shows the effectiveness of proposed wavenumber method for quantitative rectangular notch detection.

钢板-短锚结构修补张开型衬砌裂缝效果研究

为探明钢板-短锚结构修补张开型衬砌裂缝的效果,采用通用有限元软件ABAQUS对大偏心受压状态下经过钢板-短锚修补前后的钢筋混凝土衬砌力学特性、破坏形态进行对比。研究结果表明:(1)钢板-短锚结构修补裂损程度为30%、50%、70%的衬砌,相较于未修补的衬砌结构,极限承载力分别提升20.37%、24.22%、28.36%,跨中挠度值分别下降54.9%、32.5%、36.5%;(2)以衬砌裂损程度70%时极限承载力对应的跨中挠度值为基准,跨中挠度值由小到大分别为修补30%<完好构件<修补50%<修补70%<裂损30%<裂损50%<裂损70%;(3)衬砌裂损程度为30%、50%、70%时,经过钢板-短锚修补后衬砌中的钢筋最大拉应力分别下降8.24%、2.98%、10.90%,最大压应力分别下降9.38%、6.40%、0.89%;(4)衬砌结构破坏时,数值模拟和模型试验的破坏模式均相同,表现为受压侧混凝土产生不同程度压溃,经过修补后衬砌原有裂缝的扩展得到明显抑制,提升衬砌结构的整体性,降低掉块掉渣风险。钢板-短锚结构修补衬砌裂缝具有快速、微创的特点,结合以上研究结论为维修加固运营铁路隧道衬砌裂缝提供参考。

冷轧汽车板短线缺陷的分析和控制

根据冷轧连退反馈的短线缺陷(宽度0.2~0.5 mm、长度1.5~2 mm),采用扫描电镜(SEM)和电子能谱(EDS)仪分析了缺陷区域底层的物质构成,确定缺陷处的主要成分为w(Ni)=5%~7%、w(Cr)=1%~2%、w(Si)=1%~2%,与热轧精轧F4—F6无限冷硬精轧轧辊成分相同。结合缺陷的宏观特征,确定缺陷的产生机理为热轧F5—F6工作辊冷却不足,导致轧辊温度偏高,轧辊表层组织破碎剥落,压入带钢后经冷轧形成短线缺陷。通过热轧烫辊制度优化、末道次精轧负荷控制、各机架工作辊冷却水和润滑控制、F1—F6全机架高速钢轧辊配置等措施,使冷轧短线缺陷发生率由15.8%降低至1.0%。

异质多层复合板层间剪切强度测量计算方法

在现有的复合材料层间剪切强度测试方法中,用于计算强度的公式仅含有试样的几何参数而未考虑模量和中性面变化,所以仅适用于各向同性或横观各向同性复合板,对于不同材料非均匀铺设的异质多层复合板,使用该方法会得到不同严重程度的错误结果。鉴于此,本文首先构建了三层异质复合板中性面位置及层间切应力计算方法,进而推导出n层复合板中性面及层间切应力计算通式,结合短梁剪切法,建立了异质多层复合板层间剪切强度测量计算方法。计算分析表明,对于异质复合板,其最大相对层间切应力会随各层模量的变化而改变,其中性面也不再位于试样几何中心。针对GFRPP/胶/GFRPP和GFRPP/胶/钢这两类三层异质复合板的试验结果表明,本文方法能较准确地测量计算出异质复合板层间剪切强度,而现有方法则会随复合板各向异性程度的增加而逐渐偏离真实值。

短板式低标准住宅改造技术研究

针对低标准住宅建筑改造的需求,对结构改造加固方案进行研究。经分析对比,提出了扩建剪力墙、预制构件改为现浇的整体改造方案,优化原结构体系,提高结构安全度,可减少既有建筑重复拆除与建设,优化工程量,缩短工期。

气缸垫密封的“短板效应”

本文介绍了气缸垫的功能,气缸垫的密封机理及缸盖螺栓受力变形的动态三角形定则,气缸垫的结构,缸盖螺栓的影响,发动机运转试验时温度变化曲线,气缸垫密封的时间曲线,振动的影响,气缸垫设计以及发动机发展趋势对密封件的影响,气缸垫密封的安全系数及密封筋设计等诸多问题,以气缸垫密封的“短板效应”为节点作为气缸垫密封的汇总点。结论是影响气缸垫密封的因素很多,取决于发动机的特性,如发动机的参数,缸体、缸盖、接触面的刚性,缸盖螺栓及与操作有关的预紧力,以及气缸垫的设计、制造、检验与试验等。

中等烈度区矮墩小箱梁桥的减震体系研究

中小跨度小箱梁桥普遍采用板式橡胶支座,即使在中等烈度区,当墩高较矮时,地震下主梁与支座间也容易发生滑移,落梁风险较大。以中等烈度区一座4×30m连续小箱梁桥为工程背景,建立常规板式橡胶支座支承体系的桥梁有限元模型,采用非线性动力时程分析方法,进行地震响应分析,提出了板式橡胶支座(允许滑移)+钢阻尼器的组合减震体系,并对其减震效果进行了分析。结果表明:板式橡胶支座+钢阻尼器的组合减震体系可以有效控制主梁纵横向位移,在一定程度上减小下部结构地震内力。

短扶壁对干式矩形泵房外墙受力性能影响的研究

为研究短扶壁对干式矩形泵房外墙受力性能的影响,本文通过对悬臂外墙模型和8种不同墙厚短扶壁模型的计算结果进行对比分析,得出:在下部走道板下设置短扶壁能大幅减小外墙底部的弯矩,外墙厚度越小,减小的幅度越大;短扶壁模型下部走道板边缘纵向拉力随外墙厚的增加而减小;短扶壁根部的剪力随着外墙厚度的减小呈线性递增趋势。与悬臂式外墙方案相比,在下部走道板下设置短扶壁的结构方案能显著减小外墙根部弯矩,具有显著的经济效益。

基于红外成像技术的锌电解极板故障检测系统

针对传统目标检测算法泛化能力弱、特征规则设计复杂、现有深度学习模型对干扰因素较多的红外图像检测效果较差的问题,设计和开发了基于红外成像技术的电解槽极板故障检测系统。根据电解过程极板的工作情况以及实际需求,提出了极板故障检测算法、红外图像畸变矫正算法,完成了系统数据库概要设计以及软件功能设计,开发了电解槽极板故障检测系统,实现了电解过程故障极板的准确识别与定位功能,提高了电解过程的电流效率。

常规热连轧精轧稳定性的影响因素及控制措施

石横特钢1780mm热连轧生产线于2022年4月建成投产,在热负荷试车期间,中间坯镰刀弯、精轧速度和入口温度、轧机负荷分配、活套张力等因素影响了精轧轧制的稳定性。通过改善中间坯质量、减少中间坯温降、优化穿带速度以及活套控制等措施,精轧稳定性明显提升,提高了板形和终轧温度的命中率。

基于改进YOLOv5和LSTM的车牌识别技术

针对现有车牌识别技术效率低、鲁棒性差、识别精度不高等问题,文章提出了一种高精度实时环境下车牌检测和识别的端到端深度学习模型。首先,在YOLOv5网络层的下采样过程中加入了改进的通道注意力机制,该机制加入了位置信息,减少了采样带来的信息损失,提高了模型的特征提取能力;其次,基于LSTM+CTC的组合构建识别网络,完成车牌的无字符分割识别工作,大大减少了训练周期,提高了模型的识别精度和效率。文章在中国城市停车数据集(CCPD)上进行了大量实验,结果表明,文中提出的车牌识别改进模型平均识别精度达到了98.03%,明显优于传统的车牌识别技术,且在复杂环境识别效果良好,具有较强的鲁棒性。