Non-circular cutting with a lathe using a three-stage intelligent controller

In this paper, a three-stage intelligent controller (TSIC) for non-circular cutting with a lathe (NCL) is developed. In the first stage, an effective neural network is used to learn the dynamics of the voice coil servomotor system. Then a modified zero-phase tracking control (MZPTC) based on the learned model is designed to obtain an acceptable tracking result. Because MZPTC is a type of feedforward control, its performance cannot be ensured as the system is subjected to external load or the aging of system components. In the second stage, an adaptation in control input generated by a fuzzy sliding-mode control is then synthesized with the previous MZPTC to ameliorate control performance. The third stage is to use a forecast compensate control to compensate the cutting error caused by the variant cutting depth (or cutting force). The experimental results of NCL using TSIC, including tracking accuracy (i.e. profile error of finished workpiece) and smoothness of control input (i.e. surface roughness of finished workpiece), are much improved.     

振动测试在工程中的应用

将用于桩基检测的动测法,推广应用于地下连续墙纵向接缝刚性和强度的测试。测试结果表明接缝刚性满足要求、强度没有明显降低。     

Forming-free bipolar resistive switching in nonstoichiometric ceria films

The mechanism of forming-free bipolar resistive switching in a Zr/CeO _x /Pt device was investigated. High-resolution transmission electron microscopy and energy-dispersive spectroscopy analysis indicated the formation of a ZrO _y layer at the Zr/CeO _x interface. X-ray diffraction studies of CeO _x films revealed that they consist of nano-polycrystals embedded in a disordered lattice. The observed resistive switching was suggested to be linked with the formation and rupture of conductive filaments constituted by oxygen vacancies in the CeO _x film and in the nonstoichiometric ZrO _y interfacial layer. X-ray photoelectron spectroscopy study confirmed the presence of oxygen vacancies in both of the said regions. In the low-resistance ON state, the electrical conduction was found to be of ohmic nature, while the high-resistance OFF state was governed by trap-controlled space charge-limited mechanism. The stable resistive switching behavior and long retention times with an acceptable resistance ratio enable the device for its application in future nonvolatile resistive random access memory (RRAM).     

Influence of Finite Lower-level Lifetime on the Performance in CW Four-level Laser

在考虑了有限的下能级寿命和激光能级与晶格场的相互作用的基础上，对四能级激光的速率方程组进行了求解。结果表明由于这个有限寿命的存在，激光阈值升高，输出与输入之间出现了非线性。与下能级瞬时跃迁的理想情况不同，泵浦功率增大时，四能级激光器的输出趋向于一个极限值，并且，下能级寿命越长，激光器所能获得的最大输出越小。     

经济型酒店需求量测算方法初探——以《合肥市宾馆业专项规划（2007～2020）》为例

近年来，经济型酒店建设发展迅猛，为旅游住宿设施建设带来全新理念，旅游住宿市场亦得以进一步细分，满足了更多层次客户群体需求；与此同时。也给城市（专项）规划及旅游业规划带来一个全新课题：一个城市或地区，经济型酒店具有怎样的建设量，才能与城市或地区的经济社会发展状况相匹配？文章从旅游住宿设施建设发展状况的整体入手，通过对住宿设施的内涵界定、类型、等级划分，以及未来发展趋势的分析。以住宿设施需求总量预测为基础，提出经济型酒店需求量测算的方法和途径，旨在经济型酒店建设提供相关依据。     

Improved estimation of residual capacity of batteries for electric vehicles

Abstract

This paper proposes an improved means of estimation for the residual capacity of lead‐acid batteries used in electric vehicles. The residual capacity of batteries in commercial products is usually indicated by the state of charge (SOC) of the battery set, in terms of the measurement of amp‐hours, or roughly an instant voltage. More practical and accurate SOC in the operation of electric vehicles must consider the original capacity when the battery is first installed, capacity deficiency due to high discharge rate, capacity dissipated in internal resistance, and correcting parameters for the battery aging process. The proposed estimation techniques include the amp‐hours measurement weighted by a correction function of various discharge rates, the transient open‐circuit voltage measurement to compensate for the energy dissipation from internal resistance, and the reset of parameters in the linear function of SOC and open‐circuit voltage for the aging effect. A monitoring circuit with a programmable logic chip is implemented, and the experimental results show that a more accurate indication of SOC is achieved using the modified estimation techniques, namely a weighted ampere‐hour measurement with transient open‐circuit voltage combined with the aging effect.     

有限的下能级寿命对四能级激光器工作特性的影响

在考虑了有限的下能级寿命和激光能级与晶格场的相互作用的基础上, 对四能级激光的速率方程组进行了求解。结果表明由于这个有限寿命的存在, 激光阈值升高, 输出与输入之间出现了非线性。与下能级瞬时跃迁的理想情况不同, 泵浦功率增大时, 四能级激光器的输出趋向于一个极限值, 并且, 下能级寿命越长, 激光器所能获得的最大输出越小。     

汽车悬架系统非线性振动的主动控制

首次采用微分几何理论,提出了一种输出－干扰解耦法,对汽车悬架系统的非线性振动的主要控制进行了研究。通过适当的非线性坐标交换,将其简化为线性系统,并对此系统进行最优控制,再通过非线性状态反馈实现对原系统的主动控制。仿真结果表明,这种针对现有元件非线性特性的方法既符合实际情况又有良好的控制效果。