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Search Results: 1 - 10 of 107680 matches for " 宋爱平 "
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基于混沌理论的室内轰燃判据
,
爆炸与冲击 , 2010, DOI: 10.11883/1001-1455(2010)06-0622-06
Abstract: ?根据混沌理论,在研究大量小规模室内火灾实验结果的基础上,得到了一种新的、通过温度变化率表征的轰燃判据;利用大规模室内火灾的实验结果,对该判据的实用性进行了初步验证。结果表明这一判据可以应用于预测大规模实际室内火灾中轰燃的发生。
三次三角插值样条曲线的数控插补计算方法
An NC Interpolation Calculation Method of Cubic Trigonometric Cardinal Interpolation Spline
 [PDF]

张益汉, , 刘祖奇, 邱林
Mechanical Engineering and Technology (MET) , 2015, DOI: 10.12677/MET.2015.42016
Abstract:
论文提出一种新的样条曲线——可调形三次三角插值样条曲线,该样条曲线实现了对直线、圆弧、椭圆以及自由曲线等常见数控运动轨迹曲线的统一精确表达,并根据参数曲线的数据采样插补原理,对三次三角插值样条曲线的插补算法进行了研究。在保证自由曲线数控插补运动高速同时兼顾运动的平稳性,采用一系列首尾相连的微小直线段逼近给定的插值样条曲线,再利用轨迹空间和参变量空间的对应关系,控制运动加速度,得到整个离散化插补轨迹。此算法提高了自由曲线的插补速度和运动平稳性,保证了曲面数控加工的表面质量。
The paper proposes a new spline curve called cubic trigonometric cardinal interpolation spline with adjustable shape. The spline curve realized the unification to accurately represent some common NC tool motion path curves such as straight lines, arcs, ellipses and free curves, etc. An interpolation algorithm of cubic trigonometric cardinal interpolation spline based on data sampling interpolation theory is researched. This curve interpolation method ensures the high-speed of spline curve CNC interpolation while taking into account the smooth movement, using a series of conterminous short straight-line segments to approach the given interpolation spline, and then utilizing the relation between track space and parameter space to control motion acceleration and get the whole discrete interpolation trajectory. This algorithm improves the speed and motion stability of free curve interpolation and guarantees the surface quality of surface numerical control machining.
渐开线弧齿圆柱齿轮副抗偏载特性的研究
Anti-Bias Load Capacity Analysis of the Involute Arc Cylindrical Gear
 [PDF]

刘祖奇, , 张益汉, 罗超
Mechanical Engineering and Technology (MET) , 2015, DOI: 10.12677/MET.2015.43023
Abstract:
在齿轮副传动过程中,常因加工误差、安装误差、受力变形引起齿轮副偏载。分析了直齿圆柱齿轮副、斜齿圆柱齿轮副的偏载产生机理及齿轮修形的局限性,提出应用新型弧齿圆柱齿轮,来提高齿轮副传动承载能力与抗偏载能力。基于弧齿圆柱齿轮独特的几何特征分析了弧齿圆柱齿轮抗偏载的原理,采用有限元分析方法分别对直齿、斜齿、弧齿圆柱齿轮副进行受力分析,结果显示弧齿圆柱齿轮可以明显改善齿轮副齿面受力状态,具有明显的抗偏载特性。
The processing errors, installation errors and deformation often lead to Gears partial load during gear pair transmission process. The paper analyzes generating mechanism of partial load and limitations of gear modification about the spur gear pair as well as the Helical Gear Pair, proposing to use this new arc cylindrical gear to improve the carrying capacity and anti-bias load capacity of the auxiliary drive gear. The paper analyzed the principle of anti-bias arc cylindrical gear carrier based on the geometric characteristics of the arc cylindrical gear, using the finite element method to analyze the stress of straight teeth, Helical and arc tooth cylindrical gear pairs respectively, showed that the arc cylindrical gear pairs can significantly improve the stress state of tooth surface, with a clear anti-side load characteristics.
舷侧结构与冰碰撞的有限元仿真方法
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大连海事大学学报 , 2013,
Abstract: 利用有限元数值仿真方法模拟船舶舷侧与浮冰的碰撞,并对碰撞后的计算结果进行定性和定量分析,获得船舶舷侧结构的损伤变形情况、能量变化情况以及应力、应变情况.最后,针对多种工况对舷侧结构的塑性变形进行总结归纳,获得计算冰区船舶安全航速的方法.
直齿圆锥齿轮与弧齿圆锥齿轮轮齿应力比较
The Comparison of Straight Tooth Bevel Gear and Spiral Bevel Gear about the Stress of Gear Tooth
 [PDF]

张钦搏, , 罗超, 张海滨, 王树凤
Instrumentation and Equipments (IaE) , 2016, DOI: 10.12677/IaE.2016.42002
Abstract: 大型的数控龙门加工中心中,卧式主轴头通过一对直齿圆锥齿轮副来作为相交轴的传动部件。其加工中心在高速运转时,直齿圆锥齿轮副会发出大的噪声和冲击,导致加工中心的加工质量和精度下降。为了解决这一问题,提出采用弧齿圆锥轮副代替直齿圆锥齿轮副。基于ANSYS Workbench软件,分析直齿圆锥齿轮副与弧齿圆锥齿轮副的齿跟弯曲应力和齿面接触应力的状况,在此基础上,得出弧齿圆锥齿轮副在传动过程中其轮齿的综合力学性能要优越于直齿圆锥齿轮副相应的轮齿性能。这使得数控龙门加工中心可回转式卧式主轴头在更换前70分贝的噪声降至到60分贝,噪声得到了显著的降低。
In the large CNC gantry machining center, through a pair of straight bevel gear pair, the horizontal spindle head is used as a driving part for intersecting axes. When it in high-speed operation, straight tooth bevel gear pair makes a big noise and impact, which results in a decline in the quality and machining precision of the machining center. In order to solve this problem, it is proposed that the spiral bevel gear pair is used instead of the straight bevel gear pair. Based on ANSYS Workbench software, the status of straight tooth bevel gear pair’s and the spiral bevel gear pair’s the bending stress and contact stress are analysed. On this basis, it is concluded that spiral bevel gear pair, in the transmission process, of the comprehensive mechanical properties of the tooth is superior to the gear's performance of the corresponding straight tooth bevel gear pair. This makes CNC gantry machining center which can be rotary horizontal spindle head dropped to before re-placing 70 decibels of noise to the 60 decibels, which is significantly reduced.
利用预应力原理提升龙门机床横梁的抗弯强度
Promoting the Bending Strength of the Beam of Gantry Machine Tool by the Principle of Prestress
 [PDF]

罗超, , 张钦搏, 王树凤, 张海滨
Mechanical Engineering and Technology (MET) , 2016, DOI: 10.12677/MET.2016.52017
Abstract:
横梁是龙门机床的重要部件之一,与其他部件相比,它所承受的力及弯矩较大且方向较为复杂。如果横梁的自身抗弯强度不足,会产生明显的向下变形,将给龙门机床的加工精度产生一定的影响。本文利用预应力原理提升横梁的抗弯强度,建立预应力横梁的受力模型,分析横梁挠度与预应力的关系,并利用有限元方法对预应力横梁进行验证。结果表明应用预应力原理提升横梁抗弯性能是切实可行的,中部挠度减小了约80%,有效的增加了龙门机床的加工精度。
Beam is one of the important parts of gantry machine tool; compared with other parts, it bears the force and bending moment that is larger and has more complex direction. If a beam of its bending strength is insufficient, it will produce obvious deformation down and bring about the processing precision of gantry machining center with a great influence. In this paper, based on the principle of prestressing, the bending strength of the beam is promoted, the force model of the prestressed beam is established, the relationship between the deflection of the beam and the prestress is analyzed, and the finite element method is used to verify the prestressed beam. The results show that it is feasible to apply the principle of prestress to improve the bending resistance of beams, and the deflection reduced about 80%, increasing the machining precision of the gantry machine tool effectively.
可重组制造系统缓冲区容量的优化研究
士刚,,徐立云
计算机集成制造系统 , 2008,
Abstract: 为了确定可重组制造系统中的缓冲区容量,通过分析机床工作状态、生产需求量等因素对缓冲区容量的影响,建立了缓冲区状态数学模型。在此基础上,提出了缓冲区容量、机床可用度和任务需求率之间的函数关系。以满足生产任务为前提,将重组后加工域缓冲区容量最小化作为优化目标。通过粒子群优化算法,利用非可微精确罚函数法处理约束条件,采用可变惯性权重平衡搜索,以求得各工序间缓冲区容量。最后结合仿真实例,探讨了该生产线重组后系统缓冲区容量的最优配置。
基于矢量基学习的最小二乘支持向量机建模
,执环,
控制理论与应用 , 2007,
Abstract: 为使最小二乘支持向量机的解具有稀疏性,本文提出了一种稀疏解算法--矢量基学习.首先引入基矢量、基矢量集与矢量空间的概念,并分析新样本矢量与矢量空间的夹角,从而推导出该样本是否为基矢量的判断准则.随着新样本的到来,在线判别支持向量,使LS-SVM的支持向量具有稀疏性.提升LS-SVM动态建模的实时性,本文进一步提出用于矢量基学习的增长记忆模式递推公式.仿真分析及水处理厂的应用实例,验证了该方法的可行性和有效性.
22种化妆品急性皮肤刺激试验结果分析
,江红梅,何丹江,蒋志林,
中国公共卫生 , 2001, DOI: 10.11847/zgggws2001-17-05-02
Abstract: ?为对市售化妆品进行安全评价,我们对冷烫剂、香波、染发剂、浴液等样品做了急性皮肤刺激试验.现将结果报告并讨论如下.材料和方法多数样品是厂家送检的产品,少数样品来自市场.样品中有冷烫剂8种,香波4种,染发剂6种,浴液4种共22种.试验动物大耳白成年兔由中国医科大学实验动物部提供.
制备方法对CuO―Ce0.7Zr0.3O2催化剂的氧缺位和CO氧化活性的影响
洪庆红,宇鹏,,普志英,罗孟飞
分子催化 , 2008,
Abstract: 采用溶胶-凝胶法和溶胶-凝胶 浸渍法两种方法制备了CuO-Ce0.7Zr0.3O2催化剂,并对催化剂进行了XRD、Raman等表征,考察了催化剂的CO氧化性能.研究结果表明,溶胶-凝胶法制备的CuO-Ce0.7Zr0.3O2催化剂的CO氧化活性明显高于溶胶-凝胶 浸渍法制备的CuO/Ce0.7Zr0.3O2催化剂,CuO-Ce0.7Zr0.3O2催化剂容易形成氧缺位和表面高分散CuO的颗粒较大,从而提高催化活性.
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