凝结泵高压变频器几种冷却方式的可行性论证

高压变频器应用中的设备散热和运行环境问题一直是变频器生产厂家和现场应用所关心的问题之一。本文介绍了几种冷却方式,并以2240kW凝结泵高压变频器的冷却解决方案为例,对这几种冷却方式进行可行性分析论证。     

直接序列扩频通信系统三种干扰方式的仿真

介绍了直接序列扩频通信系统的三种干扰方式,设计了基于simulink的干扰信号产生模块,并仿真了其频谱图。最后仿真出干扰方式对直扩系统影响的误码率曲线,证明了设计的三种干扰信号产生方式能够有效地干扰通信系统。     

基于高速DSP的跳频通信系统设计

文章研究了跳频通信的实现方法,提出了一种基于高速DSP的跳频通信系统的硬件实现方案,详细给出了跳频控制模块的硬件设计、跳频同步方法、伪码的产生和部分电路设计。该系统可应用于短波和超短波跳频通信装备。     

Leveraging Bioinspired Structural Constraints for Tunable and Programmable Snapping Dynamics in High-Speed Soft Actuators

Creating high-speed soft actuators will have broad engineering and technological applications. Snapping provides a power-amplified mechanism to achieve rapid movements in soft actuators that typically show slow movements. However, precise control of snapping dynamics (e.g., speed and direction of launching or jumping) remains a daunting challenge. Here, a bioinspired design principle is presented that harnesses a reconfigurable constraint structure integrated into a photoactive liquid crystal elastomer actuator to enable tunable and programmable control over its snapping dynamics. By reconfiguring constrained fin-array-shaped structure, the snapping dynamics of the structured actuator, such as launching or jumping angle and height, motion speed, and release force can be on-demand tuned, thus enabling controllable catapult motion and programmable jumping. Moreover, the structured actuators exhibit a unique combination of ultrafast moving speed (up to 2.5 m s⁻¹ in launching and 0.22 m s⁻¹ in jumping), powerful ejection (long ejection distance of ≈20 cm, 35 mg ball), and high jumping height (≈8 cm, 40 times body lengths), which few other soft actuators can achieve. This study provides a new universal design paradigm for realizing controllable rapid movements and high-power motions in soft matter, which are useful for building high-performance soft robotics and actuation devices.     

An Artificial Motion and Tactile Receptor Constructed by Hyperelastic Double Physically Cross-Linked Silk Fibroin Ionoelastomer

Ionotronic artificial motion and tactile receptor (i-AMTR) is essential to realize an interactive human-machine interface. However, an i-AMTR that effectively mimics the composition, structure, mechanics, and multi-functionality of human skin, called humanoid i-AMTR, is yet to be developed. To bridge this technological gap, this study proposes a strategy that combines molecular structure design and function integration to construct a humanoid i-AMTR. Herein, a silk fibroin ionoelastomer (SFIE) with double cross-linked molecular structure is designed to mimic the composition and structure of human skin, thereby resolving the conflict of stretchability, softness, and resilience, suffered by many previously reported ionotronics. Functionally, electromechanical sensing and triboelectricity-based tactile perception are integrated into SFIE, to enable simultaneous perception of both motion and tactile inputs. By further leveraging the machine learning and Internet of Things (IoT) techniques, the proposed SFIE-based humanoid i-AMTR precisely senses the movement of human body and accurately sortball objects made of different materials. Notably, the success rate for 610 sorting tests reaches as high as 92.3%. These promising results essentially demonstrate a massive potential of humanoid i-AMTR in the fields of sorting robots, rehabilitation medicine, and augmented reality.     

高层建筑物的外墙清洗

为适应高层建筑物外墙清洗技术在我国迅速发展的形势特编写此文，文章主要介绍了高层建筑物外墙清洗的设备和方法。针对建筑物污垢的成分、结构，附着方式和外墙材料理化性质及结构，指出清洗剂一般采用表面活性剂和助剂配成的水基洗济剂。并详细介绍了具体的清洗剂配方。     

海底高频地震仪观测系统优化设计及其在南海天然气水合物勘探中的应用

海底高频地震仪（HF-OBS）可获得含天然气水合物（以下简称水合物）层的纵横波速度、波阻抗等多种有效地震反射信息,对准确估算水合物的资源量具有重要意义。根据我国南海北部海底水合物HF-OBS勘探实例,基于射线追踪法、双聚焦法、波动方程的正演模拟法3种方法,对HF-OBS观测系统进行了优化设计,并利用纵横波联合走时反演获得了该区含水合物层的纵横波速度关系。结论认为：①采用射线追踪法模拟目的层射线分布和叠加次数,同时结合波动方程的正演模拟结果,可以有效地进行观测系统优化设计;②双聚焦理论的参数模拟能够进一步验证观测系统设计的合理性,针对特定的水合物目标体,为了获取矿体内部精细的速度结构,HF-OBS的分布形态应采用长方形或正方形的矩阵分布,分布间距以300～500 m为宜;③优化后的观测系统有利于获得高质量的HF-OBS地震数据,而纵横波联合反演获得的速度信息减小了水合物识别的不确定性。     

空冷风机U型螺栓断裂原因分析及解决

针对中国石油克拉玛依石化公司某柴油加氢改质装置空冷风机固定叶片的U型螺栓接连发生多起断裂失效事故开展研究分析,发现U型螺栓的断裂主要是由于叶片安装时U型螺栓预紧力不足使其长期在松弛状态下运行造成疲劳断裂。而U型螺栓内部也存在较高的应力区域、风机叶片共振等外部因素则加速了其断裂。通过采取将风机U型螺栓更换为夹板式固定螺栓、其余型号风机将叶片轴一阶定位改造为二阶双向定位、严格规范叶片安装角度及螺栓预紧力等一系列改造措施后,空冷风机U型螺栓断裂问题得到有效解决。改造后的空冷风机已安全平稳运行14 000 h,消除了空冷机组运行中的重大安全隐患,取得了较好的改造效果。     

大牛地气田气井无阻流量的确定方法研究

大牛地气田气井试井大多采用一点法，由于气层渗透性差，测试时间短，流压很难达到稳定，计算的无阻流量往往偏高，且无法获得正确的产能方程。通过气田多口井修正等时试井数据进行统计分析，获得了一点法试井在不同生产时间下计算无阻流量的经验公式；利用气田修正等时试井的二项式方程系数曰，计算惯性阻力系数并经过曲线回归处理获得了经验关系式，很好地解决了一点法试井计算产能方程的问题。     

具有底水边界的水平井压力不稳态特征分析及认识

根据水平井三维渗流特征，在底水油藏情形仍假定顶面为不渗透隔层所封闭，底部则是恒压边界，水平井渗流表现为早期径向流以及稳定流动期，由此进行常规试井分析。以TKxxDH井为例，通过水平井的静压、压恢试井资料结果的对比分析，阐述了不稳定试井资料的应用，为此类油藏油井模型的选择及效果评价提供了可借签的经验。