峨口铁矿1932排土场稳定性对泥石流形成的影响

本文针对山西峨口铁矿1932排土场稳定性问题讨论了排土场稳定性对泥石流形成的影响,通过现场调查、观测并结合室内模型实验及理论计算,作者认为:岩土混排,土场基底充分饱水和暴雨泾流是该土场可能形成泥石流的根本原因。     

反馈控制理论在直流控制系统中的应用

使用直流控制系统实现转速或位置控制时,必须使用闭环反馈控制来实现。此文建立了这种系统的数学模型,分析了系统的绝对稳定性和相对稳定性,并提出了改善系统稳定性的方法和如何排除不稳定因素出现,为正确分析和设计直流控制系统提出了理论依据     

聚合物稳定化助剂的现状与发展趋势

重点介绍了国外部分聚合物稳定化助剂的现状与发展趋势,简述了国内合成材料及其稳定化助剂的需求。     

高稳定环氧树脂乳液的制备

通过选择最佳的乳化剂及乳化工艺条件来制备稳定性优良的环氧树脂乳液。     

PSN掺杂对锆钛酸铅特性的改善

研究了通过掺杂Ｐｂ（Ｓｎ１／３Ｎｂ２／３Ｏ３［ＰＳＮ］对Ｐｂ（ＴｉｙＺｒ２）Ｏ３系陶瓷热稳定性及老化特性的改善,试验表明加入一定量的ＰＳＮ组成的陶瓷体系,居里温度提高,高温下的热稳定性和老年特性均得以改善,满足了高温下高性能的压电换能元件的需要。     

三（2,2—二溴甲基—3—溴丙基）磷酸酯的热性能及其阻燃聚丙烯的研究

对三（２,２－二溴甲基－３－溴丙基）磷酸酯（ＴＰＢ－３０７０）的热性能及其阻燃聚丙烯进行了研究。热性能研究结果表明,ＴＰＢ－３０７０的热稳定性能优于传统的ＨＢＣＤ和ＴＢＣ,起始分解温度分别高６０℃和８０℃。对其用于聚丙烯的阻燃研究中发现,在用量较低的情形下ＴＰＢ－３０７０与Ｓｂ２Ｏ３有良好的协同效应,随着用量的增加这种协同效应逐渐减弱。研究结果表明ＴＰＢ－３０７０具有优异的热稳定性和对聚丙烯优良的阻燃和加工性能。     

用于ATM网络的拥塞避免算法（CAPCA）的稳定性分析

ＡＴＭ论坛流量管理规程４．０给出基于速率（Ｅｘｐｌｉｃｉｔ Ｒａｔｅ）的ＡＢＲ拥塞控制算法的三个例子（ＥＰＲＣＡ。ＣＡＰＣＡ,ＥＲＩＣＡＡ）。在文中,我们研究了ＣＡＰ（收敛性,稳定性,敏感性…）,我们证明了ＣＡＰＣＡ是边缘稳定的,并且对许多参数敏感,本文对ＣＡＰＣＡ作了改进,仿真结果表明,改进后的ＣＡＰＣＡ是稳定的。     

Globally stable PID-like control of mechanical systems

Decoupled PID control with actuator constraints and velocity measurement or estimation achieves global asymptotic stability of the desired configuration, if there is some friction in the controlled mechanical system and the signals to be integrated are limited accordingly. Stability analysis using the direct Lyapunov method and Gershgorin's “circle theorem” gives these limits and physically meaningful lower bounds on position control gains. A simple procedure is proposed for selecting the design parameters and determining the gains of the controllers.     

Dynamics of multiple parallel boiling channel systems with forced flows

This work investigates the nonlinear dynamics of multiple parallel boiling channels with forced flows by using the Galerkin nodal approximation method. The stability maps for multiple-channel systems subject to a constant total mass flow rate are constructed on the basis of the average heat flux and mass flow rate on the parameter plane of the subcooling and phase change numbers. The limit cycle oscillations for 3-, 4- and 5-channel systems indicate that the most heated channel exhibits the largest magnitude of oscillation, and is out-of-phase with the other channels. Owing to that the boiling assembly contains only a small number of channels, the above system becomes unstable due to channel-to-channel interaction with an increase of the channel number. This work also elucidates the dynamics of a 3-channel system with a periodic total mass flow rate. In addition, complicated nonlinear oscillations are predicted for different operating points with high inlet subcooling numbers in the stable region. The system dynamics are highly sensitive to the frequency of the forcing function. Periodic, quasi-periodic and chaotic oscillations may appear in the forcing function system. Unstable oscillations appear when either the frequency of the forcing function is equal or extremely close to the system’s natural frequency or the two frequencies are frequency-locking.     

泥页岩比表面积测定方法研究

泥页岩比表面积与泥页岩水化特性、力学性质以及渗水性密切相关,是评价泥页岩井壁稳定性的关键参数。实验研究证明,EGME法和亚甲基蓝吸附法是重复性好、准确可靠的泥页岩比表面积测定方法。其中,亚甲基蓝法更简便易行。亚甲基蓝法测定比表面积主要与吸附时间、动静状态、岩样粒度及离子交换预处理等因素有关,特别是受亚甲基蓝溶液初始浓度的影响最显著。