汽车前轴用40Cr钢锻件开裂失效分析

利用化学成分、显微组织以及硬度分析等方法,对汽车前轴用40Cr钢锻件的开裂原因进行了分析。结果表明:裂纹位于锻件的R角处,为淬火裂纹;锻件R角处的元素偏析造成淬透性显著高于周围其它位置,锻造过程中产生了表面缺陷,使得淬火时马氏体相变产生的体积内应力超过了材料的强度,造成了淬火裂纹的产生;通过增大R角半径、控制原材料的成分偏析以及调整锻造工艺等措施,能够减小汽车前轴用40Cr钢锻件热处理后淬火开裂的风险。     

架棚巷道前探梁液压自移可升降技术研究

针对煤矿井下架棚巷道使用的临时支护技术存在前探梁比较笨重、操作不便、作业人员劳动强度大、施工效率低、安全隐患大等问题,开展了架棚巷道前探自动化技术研究,对传统前探梁进行了优化改进,实现了架棚巷道前探梁的自动化,并形成了架棚巷道前探梁液压自移可升降技术。实践结果表明,该技术有效解决了传统前探梁存在的问题,改善了架棚巷道的临时支护方式,实现了架棚巷道前探梁的自动化,使前探梁的安全性能得到了极大提升,同时也降低了临时支护工序作业时间和职工的劳动强度,对架棚巷道掘进、扩修施工时的安全管理和工效提升有显著的作用。     

带前模抽芯的S型阀室注射模具设计

根据塑件结构特点与生产批量要求确定模具的总体布局。在模流分析的基础上设计出热流道与普通流道相结合的浇注系统,保证各个型腔均衡充填,确保塑件与浇注系统冷料自动分离;通过设计哈弗滑块结构的侧向抽芯方式,装配受压弹簧和设置限位机构,实现模具前膜抽芯;设计小推板推出机构,简化模具的整体结构,确保脱模推出动作合理可靠。后期生产实践证明：该模具结构合理,能实现自动化生产,模具成型周期与塑件质量符合设计要求。     

畲族女装服斗造型及纹样特征研究

服斗是畲族女装中最具民族特色的装饰之一,其纹样造型的艺术表现形式可为现代服饰设计提供设计灵感。文章以景宁畲族自治县博物馆、福建省闽东畲族博物馆中12件具有代表性畲族女上衣为研究对象进行归纳分析,测量其各部位尺寸,并通过Adobe Illustrator软件对服装图片进行线描表现,截取部分代表性的服斗细节部位的结构图进行梳理分析。研究表明:畲族女装服斗纹样造型具有“厂”字型、“几”字型、“Z”字型的多样结构特点;包罗万象的纹样题材、浓艳瑰丽的配色风格、以简驭繁的刺绣工艺呈现畲族女装服斗纹样特征,这些都反映了畲族人民的智慧和对美好理想的追求与向往。     

Adhesion and Wetting Hysteresis of a Metal (Mercury) on an Oxide Glass in Air and Nitrogen

In general, oxygen can considerably change the wetting behavior of oxides by molten metals. This work is a basic illustration of the oxidation effect on the wetting behavior of glass by a liquid metal. Taking mercury as a model of a metal, the importance of the metal oxidation in the glass/metal interaction has been observed by measuring wetting contact angles of mercury on glass and the ability of calibrated mercury drops to slide down, under gravitation, on an inclined glass plate in air or in nitrogen. It is believed that the highest force of detachment by sliding of the mercury drop in air results from the metal oxidation which can be interpreted by a higher contact angle hysteresis when the metal is exposed to air.     

Performance enhancement of the artificial neural network–based reinforcement learning for wind turbine yaw control

The yaw angle control of a wind turbine allows maximization of the power absorbed from the wind and, thus, the increment of the system efficiency. Conventionally, classical control algorithms have been used for the yaw angle control of wind turbines. Nevertheless, in recent years, advanced control strategies have been designed and implemented for this purpose. These advanced control strategies are considered to offer improved features in comparison to classical algorithms. In this paper, an advanced yaw control strategy based on reinforcement learning (RL) is designed and verified in simulation environment. The proposed RL algorithm considers multivariable states and actions, as well as the mechanical loads due to the yaw rotation of the wind turbine nacelle and rotor. Furthermore, a particle swarm optimization (PSO) and Pareto optimal front (PoF)‐based algorithm have been developed in order to find the optimal actions that satisfy the compromise between the power gain and the mechanical loads due to the yaw rotation. Maximizing the power generation and minimizing the mechanical loads in the yaw bearings in an automatic way are the objectives of the proposed RL algorithm. The data of the matrices Q (s,a) of the RL algorithm are stored as continuous functions in an artificial neural network (ANN) avoiding any quantification problem. The NREL 5‐MW reference wind turbine has been considered for the analysis, and real wind data from Salt Lake, Utah, have been used for the validation of the designed yaw control strategy via simulations with the aeroelastic code FAST.     

球式热风炉前置预热工艺工程化研究

针对我国钢铁企业存在风温低、高热值煤气短缺的情况,提出了一种利用单一低热值高炉煤气获得高风温的前置预热工艺技术.该工艺技术把高炉煤气和助燃空气分别预热到200℃和400℃,配套采用球式热风炉,热风温度可以达到1 200℃以上,同时计算了工艺中涉及到的各种参数,对工艺和设备进行了设计或选型.在该项目建成后进行了生产调试,高炉正常运行后,热风温度可提高80～100℃.     

准噶尔盆地玛中地区二叠系—三叠系叠合成藏特征及主控因素

玛湖凹陷是准噶尔盆地目前已发现油气富集程度最高的生烃凹陷,其中二叠系—三叠系具有较大的勘探潜力.为了研究其叠合成藏特征及主控因素,开展了录井、测井、岩心分析化验及试油资料分析,并进行了三维地震资料解释.结果表明:①玛中地区发育二叠系下乌尔禾组和三叠系百口泉组2套优质储层,扇三角洲前缘亚相是研究区油气富集的有利相带;在湖...     

基于mTCA平台的射频前端板性能测试与研究

上海软X射线自由电子激光装置中C波段直线加速器的工作频率为5 712 MHz。在低电平系统中,C波段的射频信号需要在射频前端板上与5 686.556 MHz的本振信号进行混频后下变频为26.444 MHz的中频信号,之后由时钟频率为105.778 MHz的采样信号进行采样。针对C波段低电平的整体性能的物理设计需求,设计了基于mTCA平台的DWC8VM1板卡作为低电平控制系统的射频前端板。对射频前端板的输入端回波损耗,射频输入端口间隔离度、输入输出线性度、信号噪声、幅相稳定性、上变频通道的附加相位噪声等参数进行了实验测试,测试结果表明,端口的输入损耗大于8.63 dB,端口之间的隔离度大于63 dB,幅度和相为稳定度可达±0.04%和±0.05°,上变频通道附加相位噪声小于2 fs。该设计的射频前端板性能能很好地满足SXFEL理论设计中低电平控制系统的要求,达到国际同类装置的先进水平。     

小麦制粉过程前、中、后路粉品质及流变学特性差异分析

出于对成本的考虑,目前国内外淀粉、谷朊粉一般利用后路粉进行生产,虽然后路粉制备的淀粉、谷朊粉产量高,但是质量较差.基于这种现状,利用粉质仪、拉伸仪及流变仪对3种小麦粉的前、中、后路粉的品质及流变特性进行了比较分析,探究各路粉之间存在的具体差异性.研究表明:各小麦粉由前路到后路,其灰分、蛋白质含量、干湿面筋含量、降落数值...