高效固体缓释型阻垢剂的研制及性能分析

针对大庆油田集输管道腐蚀结垢现象,以主剂、分散剂、特殊缓蚀阻垢剂和载体配制固体缓蚀阻垢剂,通过复配试验筛选出适合其采出液水质的药剂,并对其缓蚀和阻垢性能进行分析。结果表明:加注药剂后的管道钢腐蚀速率为0.070mm/a,远低于未加注前的0.310mm/a;阻垢效果15天内稳定,阻垢率约为91%,阻垢性能良好;缓释速率为约每10天溶解8%,加注周期约为3个月。所制备药剂性价比高,缓蚀阻垢综合性能良好,可作为油田水驱采出液专用缓蚀阻垢药剂。     

Low variation in relative permittivity over the temperature range 25–450 °C for ceramics in the system (1 − x)[Ba0.8Ca0.2TiO3]–x[Bi(Zn0.5Ti0.5)O3]

The dielectric and ferroelectric properties of the ceramic system, (1 − x)Ba_0.8Ca_0.2TiO₃–xBi(Zn_0.5Ti_0.5)O₃, were investigated for compositions 0 ≤ x ≤ 0.4. X-ray powder diffraction patterns indicated tetragonal symmetry at x ≤ 0.05, switching to pseudocubic at x ≥ 0.1, with a single-phase solid solution limit at 0.2 < x < 0.3. The x = 0 and 0.05 samples were ferroelectric; a change to relaxor behaviour occurred at x ≥ 0.1, with broad frequency dependent peaks in plots of relative permittivity versus temperature. A significant reduction in the temperature dependence of relative permittivity occurred at x = 0.3, with ɛ_r = 1030 ± 15% over the temperature range ∼25–425 °C, and loss tangent, tan δ ≤ 0.01 from 110 °C to 420 °C. The dc resistivity values for x = 0.3 were ∼10⁹ Ω m at 300 °C and ∼10⁶ Ω m at 450 °C.     

空间机械臂在平衡状态流形上的小振动与稳定性

研究了一类空间自由飘浮的平面2R机械臂在平衡状态流形上的小振动稳定性。考虑动量矩守恒具有非完整约束性质,建立了考虑控制力矩作用的非完整动力学方程。在小振动的条件下把系统的动力学方程线性化,然后根据赫耳维茨判据研究了该系统在平衡状态的流形上的稳定性条件。仿真结果表明,系统在平衡状态流形上的小振动一般是不稳定的,只在特定初值下存在少量稳定的平衡状态流形。考虑到系统具有复杂的非线性,在稳定流形和不稳定流形之间可能存在复杂的穿插和其他非线性现象。     

弱光环境下仓库搬运机器人抓取控制方法

为精准、稳定、可重复地完成抓取动作,研究了弱光环境下基于稳定轻量级网络的仓库搬运机器人抓取控制方法。首先,针对搬运环境弱光图像,基于稳定轻量级编/解码网络提取抓取区域弱光特征并进行融合处理,获得正常光抓取区域特征;其次,在深度分离融合提取层中,通过处理正常光抓取区域特征,重构深层特征,从而恢复特征提取时丢失的细节信息;再次,在网络输出层内输入重构特征,输出仓库搬运机器人手爪的抓取位姿参数;最后,通过手眼标定得到的搬运目标图像,采集相机坐标系与机器人坐标系的坐标转换关系,将抓取位姿参数转换成仓库搬运机器人抓取控制量,完成对仓库搬运机器人的抓取控制。实验证明,该方法可有效提取搬运目标抓取区域特征,并可有效预测仓库搬运机器人抓取位姿,能完成仓库搬运机器人抓取控制,且抓取精度较高。     

一种快速起振中频电源的研究

中频电源是感应加热领域常用的一种设备.传统的中频电源采用扫频方式起振,其一次起振成功率不高,特别当负载变化时容易引起停振现象.针对这些问题,本文提出了一种半桥串联谐振快速起振中频电源电路.电路自动捕捉负载谐振频率,使系统自动进入谐振工作状态.通过对半桥串联谐振逆变器电路的分析、计算,再通过工作电路的实际测试,表明该设计...     

Study of plasma-based stable and ultra-wideband electromagnetic wave absorption for stealth application

A plasma-based stable,ultra-wideband electromagnetic (EM) wave absorber structure is studied in this paper for stealth applications.The stability is maintained by a multi-layer structure with several plasma layers and dielectric layers distributed alternately.The plasma in each plasma layer is designed to be uniform,whereas it has a discrete nonuniform distribution from the overall view of the structure.The nonuniform distribution of the plasma is the key to obtaining ultra-wideband wave absorption.A discrete Epstein distribution model is put forward to constrain the nonuniform electron density of the plasma layers,by which the wave absorption range is extended to the ultra-wideband.Then,the scattering matrix method (SMM) is employed to analyze the electromagnetic reflection and absorption of the absorber structure.In the simulation,the validation of the proposed structure and model in ultra-wideband EM wave absorption is first illustrated by comparing the nonuniform plasma model with the uniform case.Then,the influence of various parameters on the EM wave reflection of the plasma are simulated and analyzed in detail,verifying the EM wave absorption performance of the absorber.The proposed structure and model are expected to be superior in some realistic applications,such as supersonic aircraft.     

旋转流中预混合火焰的高速传播现象——Ⅰ.稳燃特性及燃烧效率的提高

旋转流中预混合火焰高速传播特性的研究为强化低热值燃气的稳定燃烧提供了新的开发思路.针对圆管内强制涡作用下的甲烷/空气预混合火焰,本工作采用数值模拟方法分析了混合气的进口速度和旋转角速度对预混合火焰稳定燃烧的影响.结果表明,在不同当量比条件下,使火焰稳定的混合气进口速度和旋转角速度之间存在线性关系,但随着旋转角速度的增大,火焰半径变小,燃烧效率减小.改变混合气进口速度的分布形式是提高燃烧效率的有效方法.研究结果为实际的稳燃燃烧器设计提供了理论指导.     

考虑二次规划因素的电网规划方法

电力市场环境下,针对电网结构需要进行多次扩建的问题,提出了在电网规划时考虑未来电网二次规划的可能性,对网络扩建后的可靠性因素进行量化处理的电网规划新方法。使电网规划模型在平衡了经济性与可靠性的基础上,网络结构有更强的稳定性保证,并能避免电网进行不必要的二次扩建损失。通过算例进行计算分析,结果证明该方法是合理有效的。     

Study of dynamic stable control for a leg-wheeled robot

Leggedrobotsaredrawingmoreattentionandre searchfortheirhighterrainadaptability.However,limitationsexistintheircomplexityofstabilitycontrol limitspeedandrealapplications[1,2].Usually,wheeledrobotswithhighspeedandefficiencycannotnegotiateroughterrain.Thecontrolofawheeledrobotisverysimpleandisnotconcernedwithbalanceanddynamicstableproblems.Manystudieshavecontributedtothedevelopmentofhybridleg wheeledrobots,whichcantakeadvantageofbothleggedrobotsandwheeledones.Amongthem,therearetheRoller Walkero…