排序方式: 共有58条查询结果,搜索用时 15 毫秒
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为提高单向航道散货港口的泊位利用率,研究多港池的散货港口船舶调度优化问题。考虑船舶间需保持安全航行距离、进出港时段交替条件和成簇进出港规则等现实约束,以进港船舶总等待时间最小为目标,构建了混合整数线性规划模型。基于问题的特点,设计了启发式规则与模拟退火算法相结合的混合算法进行求解。在数值实验中分别将该算法的结果同下界值和两种现实调度方案对比。结果表明,运用混合算法求解的结果与下界值的平均相对偏差为5.28%,较两种现实调度方案的目标值优化率提升显著,且平均泊位优化率分别为6.74%和4.71%,验证了方案及算法的有效性。 相似文献
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正交投影的积与差的Moore-Penrose逆 总被引:1,自引:0,他引:1
运用分块算子矩阵的方法,给出了HIlbert空间上两个正交投影的和与差的Moore-Penrose逆的一个新的表达式. 相似文献
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Some spectral characterizations of positive operators on Hilbert lattices are pre- sented.The application of these results can yield some equivalent relations of an irreducible positive operator.Some related results for positive operators on Hilbert lattice are also obtained. 相似文献
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中子星的制动机制是中子星研究中的基本问题。磁偶极辐射模型给出中子星的制动指数为3,而所有观测到的中子星的制动指数都小于3,这表明中子星除磁偶极辐射之外还存在其他的转动能量损失方式。考虑中子星的转动动能损失来自:磁偶极辐射、由于单极感应引起的粒子流逃逸以及中子星和量子真空摩引起的能量损失。基于这3 种辐射机制,给出了改进后的中子星能量损失功率的计算公式和周期对时间一阶导数与周期的依赖关系。考察了6 颗中子星( J1119–6127, B1509–58, J1846–0258,B0531+21, B0540–69 和B0833–45 ) 的周期-周期一阶导数关系,制动指数、表面磁场强度以及磁倾角之间的关系。研究表明,星风效应中,真空间隙电势差为常数时磁倾角只能在有限范围内取值,而其他情况下磁倾角在0s 90°之间连续取值。The neutron stars’ braking mechanism is a fundamental problem in the study of neutron stars. The braking index exactly equal to 3 in pure magnetodipole radiation model, however, all the observed braking index of rotationpowered pulsars is less than 3. This indicates that the additional energy loss ways must exist besides the magnetodipole radiation. The magnetodipole radiation, the ejection of particle outflow and quantum vacuum friction are considered as the source of the loss of rotational kinetic energy of rotation-powered pulsars. Based on the three mechanism of loss of the energy, the relation between the period of pulsars and the first derivative of the period to time and the pulsars’ energy losing power are given. The relationship of the periods and the first derivative of the periods of six pulsars(J1119−6127,B1509−58, J1846−0258, B0531+21, B0540−69 and B0833−45) is studied. The relation between the surface magnetic field intensity and the magnetic inclination is discussed. Research shows that when the electric potential difference of vacuum gap is a constant the inclination angle is limited in a smaller range and in the other cases the inclination is the continuous value between 0∼90 degrees. 相似文献
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通过电聚合酸性络蓝K于多壁碳纳米管修饰玻碳电极上构建了一种新的修饰电极。研究了该电极的电化学性质,结果表明:该电极表现出优异的电催化和选择性能,可在异构体存在下伏安法选择测定对苯二酚。线性范围在1×10-6~1×10-4mol.L-1,检出限为1×10-7mol.L-1。所制作的电极对水样进行了测定所得结果与光谱法的结果一致。 相似文献