烟草制丝线上调节阀流量特性的选择

介绍调节阀的控制原理,分析调节阀流量特性对控制系统的影响,结合烟草设备的工艺特性,提出烟草制丝设备上调节阀流量特性选择的原则。     

PTN网络的二次断纤链路规划算法

在PTN（PacketTransportNetwork）网络规划建设中,需要对光纤链路留出备份带宽,以保证部分光纤断开时,受影响业务有足够的容量进行路由重组。这也是提高网络生存性的有效方法之一。文中首先遍历网络双链路的失效状态,然后断开网络中任意两条链路,通过逐次增加链路容量来保证失效业务能够重组路由;最后提出二次断纤链路容量规划算法并进行试验仿真。结果表明,该算法在节约网络带宽、降低建造成本以及故障容错方面有着良好性能,能够很好应用于传送网络的链路规划中。     

反倾岩质边坡弯曲倾倒-剪切滑移破坏分析方法研究

目前反倾岩质边坡弯曲倾倒破坏分析方法仍以基于极限平衡理论的悬臂梁模型为主,但大多未考虑坡脚岩层的剪切破坏。为准确评价该类边坡的稳定性,建立考虑坡脚岩层剪切破坏的分析计算方法。首先,根据岩层变形破坏特征,将边坡分为后缘稳定区、中部弯曲倾倒区和前缘剪切区3个区域;其次,建立弯曲倾倒-剪切滑移破坏模式的稳定性分析方法;最后,通过工程实例验证,并进行参数分析。研究结果表明:提出的分析方法与工程实际符合性较好;边坡在倾角较陡、坡角较大时稳定性最差,坡角对边坡稳定性影响大于岩层倾角的影响;岩层厚度及层面内摩擦角增加有利于边坡稳定性,且会扩大坡脚剪切区范围。研究成果对反倾岩质边坡破坏的防治具有实践指导意义。     

华北中部平原地表水入渗试验 ——以南宫溹泸河为例

华北平原中部地区含水砂层颗粒细且薄,对地下水储蓄和地表水入渗不利。选择河道带进行地表水入渗试验,以获取最大地下储蓄空间,为该区水资源合理利用提供良策。试验区选在南宫溹泸河,人工引水1.5个月,获取大量监测数据,据此对地下水位和水量的变化特征、入渗量和地下水库调蓄能力进行研究,结果表明：干涸河道引水入渗,入渗比例可达80.54%;溹泸河上下游2个断面Ⅰ-Ⅰ′和Ⅱ-Ⅱ′河道垂向渗透速度为10.81 m/d和10.72 m/d;水平扩散速度为1.69 m/h和2.38 m/h。由于Ⅰ-Ⅰ′断面垂向渗透速度大于Ⅱ-Ⅱ′断面,而水平扩散速度小于Ⅱ-Ⅱ′断面,所以Ⅰ-Ⅰ′断面形成的水丘相比Ⅱ-Ⅱ′断面较为明显,且不易消散。计算结果显示,试验区调蓄库容为1.87亿m3。     

Aluminum. II. Derivation of C v0from C p and comparison to C v0 calculated from anharmonic models

The specific heat at constant pressure, C _p, of aluminum measured by Ditmars, Plint, and Shukla has been reduced to the volume V ₀ appropriate for 0 K employing the Murnaghan equation. The C _v0 thus obtained is compared with the theoretical C _v0 calculated in the harmonic and the lowest-order anharmonic approximation from three different pseudopotentials (Harrison, Ashcroft, and Dagens-Rasolt-Taylor) as well as a phenomenological Morse potential. The higher-order ( ⁴) anharmonic contributions are calculated from the same nearest-neighbor Morse potential as in the lowest-order anharmonic theory. The role of the vacancy and the higher-order anharmonic contributions to C _v0 has been examined and we conclude that the ⁴ contributions to C _v0 are much smaller than the vacancy contribution. After removal of the vacancy contribution, the reduced C _v0 is found to be in excellent agreement with the Ashcroft and Harrison pseudopotentials as well as the Morse potential including the ² and ⁴ contributions to C _v0.     

Electrochemical investigation of the iron-containing and no iron-containing AB5-type negative electrodes

The electrochemical behaviour of LaNi_3.55Mn_0.4Al_0.3Co_0.75−xFe_x (x = 0, 0.15, 0.55, 0.75) intermetallic compounds has been studied and presented [C. Khaldi, H. Mathlouthi, J. Lamloumi, A. Percheron-Guégan, Int. J. Hydrogen Energy 29 (2004) 307–311; C. Khaldi, H. Mathlouthi, J. Lamloumi, A. Percheron-Guégan, J. Alloys Compd. 360 (2003) 266–271; C. Khaldi, H. Mathlouthi, J. Lamloumi, A. Percheron-Guégan, J. Alloys Compd. 384 (2004) 249–253]. It has been deduced that the LaNi_3.55Mn_0.4Al_0.3Co_0.4Fe_0.35 compound has interesting electrochemical properties. In this paper we present the electrochemical study of LaNi_3.55Mn_0.4Al_0.3Co_0.4Fe_0.35 compound properties compared with the parent LaNi_3.55Mn_0.4Al_0.3Co_0.75 compound. Several techniques, such as, the chronopotentiometry, the constant potential discharge (CPD), the cyclic voltammetry (CV) and the linear polarization (LP) were applied to characterize these electrochemical properties. The electrochemical discharge capacity of the LaNi_3.55Mn_0.4Al_0.3Co_0.75 alloy increases to reach 294 mAh g⁻¹ after few cycles only (five cycles). However, the activation of the LaNi_3.55Mn_0.4Al_0.3Co_0.4Fe_0.35 alloy takes more than 20 cycles to be achieved and the obtained maximum discharge capacity is 194 mAh g⁻¹. The hydrogen diffusion coefficient D_H was determined by constant potential discharge and cyclic voltammetry techniques. The obtained values of the LaNi_3.55Mn_0.4Al_0.3Co_0.75 and LaNi_3.55Mn_0.4Al_0.3Co_0.4Fe_0.35 compounds are 6.29 × 10⁻¹¹ and 7.62 × 10⁻¹¹, and 2 × 10⁻⁸ and 7.5 × 10⁻⁸ cm² s⁻¹ by CPD and CV techniques, respectively. The exchange current density values, determined by a linear polarization technique, are 44 and 27 mA g⁻¹, respectively, for LaNi_3.55Mn_0.4Al_0.3Co_0.75 and LaNi_3.55Mn_0.4Al_0.3Co_0.4Fe_0.35 alloys.     

基于动态模式分解的移动用户信道容量预测算法

在多输入多输出环境下,为了能够连续预测出移动用户的信道容量并以此合理地分配用户资源,提出了一种基于动态模式分解（DMD）的信道容量预测方法及其优化方法：基于经验模态分解的选择性归一化动态模式分解（ESN-DMD）.仿真结果表明,DMD算法只适用于预测低移速低复杂度的用户信号,ESN-DMD算法可以预测不同移速的用户信道容量.     

大型软包锂离子电池的热物性实验研究

针对大型软包锂离子电池热物性参数的测定问题,提出适用于该型电池的热参数表征方法. 基于准稳态导热原理,建立电池的传热理论模型. 开展实验研究电池的比定压热容和导热系数与温度的依变关系,分析热损对测试结果的影响,对测试方法的有效性进行验证. 结果表明,电池比定压热容随着温度的升高而线性增大,导热系数受温度的影响较小. 在900 s内可以测得电池热参数在10~60 °C下的变化状况,实验验证结果显示测算精度高于92.3%,具有测算周期短、准确度高和测试灵活等优势.     

焊接箱型截面构件在不同焊缝熔深下承载力性能试验研究

为了有效改善大跨度桥梁中管翼缘焊接箱型截面构件的耐久性的问题,提出采用耐候钢代替普通钢的管翼缘箱型截面梁。同时,为了研究耐候钢管翼缘焊接箱型截面构件填充混凝土后在全熔透和部分熔透条件下的单轴承载力性能,开展了焊接矩形截面在三种不同焊缝熔深下的耐候钢管混凝土截面轴压短柱试验研究。分别测试每个试件在单轴压力作用下的静态应变、动态应变,以及竖向位移和侧向位移。对比构件承载力的试验结果及理论分析结果,得出不同熔深下焊接箱型截面管翼缘组合构件的承载力性能。研究结果表明:1）耐候钢管翼缘焊接箱型截面构件的全熔透焊缝承载力高于部分熔透焊缝承载力。2）全熔透试件开裂时的竖向位移较部分熔透试件的位移值大,而不同熔深下构件的横向位移测点L4随轴压荷载的增大而有增加,L3测点横向位移规律不明显。3）不同耐候钢管翼缘焊接箱型截面构件横向整体受拉,局部在顶部角部位置受压。构件的混凝土内部和钢板表面应变情况复杂,规律不明显。     

卡盘的若干设计计算问题

以“夹持系数”取代传统的摩擦系数；对卡盘的主要零件重新进行了受力分析，推导出能满足各零件设计计算之用的计算公式；并提出了提高卡盘夹持能力的有效措施：（１）减小卡瓦和卡圈斜面之间的摩擦系数；（２）提高卡瓦和主动钻杆之间的夹持系数