数控雕铣加工铝合金材料进给速度的优化与实验验证

针对数控雕铣机床加工铝合金件的特点,运用多目标优化理论,建立了加工成本与加工效率的数学模型.经过计算,得到了一系列的进给速度的优化解.经过实验加工和验证,最终得到了在该条件下较为理想的进给速度取值范围(Vf∈2 400～2 560 mm/min).研究表明,以该进给速度范围进行加工铝合金材料时,能够以相对较低的加工成本和较高的效率得到良好的表面质量.     

High heat generation ability in AC magnetic field for nano-sized magnetic Y3Fe5O12 powder prepared by bead milling

Nano-sized magnetic Y₃Fe₅O₁₂ ferrite having a high heat generation ability in an AC magnetic field was prepared by bead milling. A commercial powder sample (non-milled sample) of ca. 2.9 μm in particle size did not show any temperature enhancement in the AC magnetic field. The heat generation ability in the AC magnetic field improved with a decrease in the average crystallite size for the bead-milled Y₃Fe₅O₁₂ ferrites. The highest heat ability in the AC magnetic field was for the fine Y₃Fe₅O₁₂ powder with a 15-nm crystallite size (the samples were milled for 4 h using 0.1 mm? beads). The heat generation ability of the excessively milled Y₃Fe₅O₁₂ samples decreased. The main reason for the high heat generation property of the milled samples was ascribed to an increase in the Néel relaxation of the superparamagnetic material. The heat generation ability was not influenced by the concentration of the ferrite powder. For the samples milled for 4 h using 0.1 mm? beads, the heat generation ability (W g⁻¹) was estimated using a 3.58×10⁻⁴ fH² frequency (f/kHz) and the magnetic field (H/kA m⁻¹), which is the highest reported value of superparamagnetic materials.     

与轴线成定角的球头铣刀的问题与处理方法

指出了与回顾轴成定角的球头铣刀在二轴联动加工中相关设计与制造中必然遇到的难题，分析了原因，提出了解决方案和相应模型，并指出试验中的情况，因而可供同类研究参考。     

丸子技术在光电直读光谱分析中的应用

将过筛后的金属试料通过选定筛网在模具中压成圆片状丸试样，直接在电直读光谱仪上进行分析。所得数据偏差小于０．００３，优于化学分析法测得结果。     

C~n中单位球上的面积积分与BMO

设B是Cn中的单位球,S是Cn中的单位球面,Sα(f)是B上的面积积分.设f∈BMOA, 若存在正测度集E(?)S,使Sα(f)<∞在E上成立,则Sα(f)<∞在S上几乎处处成立,同时 Sα(f)∈ BMO(S)且存在常数C,使得||Sαf||*≤C||f||*.     

Local convergence results of Gauss-Newton's like method in weak conditions

In this paper, we study the convergence of Gauss-Newton's like method for nonlinear least squares problems. Under the hypothesis that derivative satisfies some kind of weak Lipschitz condition, we obtain the sharp estimates of the radii of convergence ball of Gauss-Newton's like method and the uniqueness ball of the solution.     

多次走刀时端铣加工优化对策的研究(英文)

以最大生产率和最低成本为目标并考虑各种实际约束，采用详细地优化分析和搜索法相结合的途径。叙述了多次走刀时面铣加工的优化对策。这种优化途径不但能保证全局优化，还能大大减少计算机处理时间，从而使优化对策更为适用。最后的数值模拟研究证实了该优化对策及其相应ＣＡＭ软件的正确性、实用性和优越性     

单位球上F(p,q,s)空间到Bloch型空间的复合算子

该文分别给出了单位球B上空间F(p, q, s)到空间β^α之复合算子C_{varphi}为有界算子和紧算子的充要条件.同时作为推论获得了Bloch型空间的相应结果.     

土家族棉花球的开发与创新

采用调查法对土家族棉花球运动进行挖掘、整理，通过实验对土家族棉花球运动进行创新．经过创新后的棉花球运动是一项以扣篮为显著特点的竞技体育运动，具有独特的运动环境，观赏性强、趣味性高，它对提高青少年力量、速度、耐力、灵敏、协调、柔韧、特别是弹跳能力，应变能力等素质具有特殊的锻炼价值．     

空心介质球对静磁场的屏蔽

文章通过对空心介质球的静磁场屏蔽进行理论推导，并分析静磁场屏蔽的因素．