“方变圆”变径筒状结构滑模施工技术

为解决塔式光热的核心构筑物吸热塔"方变圆"变径超高筒体结构施工难题,选用一套可变形的滑模平台系统,通过操作系统上可调千斤顶支座、门架横向液压千斤顶装置、多处可调节模板角度和收缩模板的丝杆等,使得滑模根据施工需求可在一定的范围内调节模板倾角、间距,并逐步完成收缩变形,其理论滑模允许偏角20°,最终高效完成异形结构施工。该滑模系统刚度大、承载及堆料能力强、空间大、机械化程度高,施工操作简单,安全性高,适应沙漠极端环境。全过程仅需使用一套滑模体系,就能完成方形段、方变圆的变形段及圆形段施工,大大提高了施工效率,为类似环境下相似结构的施工提供了一定的参考。     

大管径供水管线的安装与腐蚀防护分析

在近些年的发展中,我国经济水平得到了一个显著的增长,经济的增长推动了城市化的发展进程,进入21世纪,城市绿化工程建设规模呈一个稳定上升的趋势,在这种大的社会环境形势下,如何做好绿化大管径供水管线的安装与腐蚀防护工作成为了行业关注的焦点。大管径供水管线的稳定性关系着城市发展的可持续性,要从多方面做好大管径供水管线的安装工作,采取有效的措施应对管线腐蚀问题。     

Numerical Investigation of the Capture of Polydisperse Particles by Charged Droplets

The capture of particles by charged droplets was simulated by considering the electrostatic interactions of droplet-droplet and droplet-particle. The results indicate that the electrostatic repulsion between droplets leads to a dynamic accumulation mode of particles. However, the droplet spacing has an insignificant effect on the capture efficiency when the electrostatic deposition predominates. The increase of droplet charge remarkably improves the capture efficiency, in which the capture of fine particles accounts for the largest proportion. Compared to the droplet charge, the droplet size shows a limited improvement in the capture efficiency. Reducing the droplet velocity prolongs the capture time instead of enhancing the capture capacity per unit time, thereby improving capture efficiency.     

浅析火力发电厂汽水系统中内径管与外径管的设计选择

按照管道加工工艺的不同,管道可分为内径控制管和外径控制管。通过热轧工艺生产的外径控制无缝钢管,可满足火力发电厂汽水系统中绝大部分管道的使用要求。对于超(超)临界机组的主蒸汽和高温再热蒸汽管道采用的P91/P92材质的大口径厚壁无缝钢管,由于对材料性能和加工工艺有特殊要求,因此宜采用内径控制管。     

煤层顶板硬岩大直径定向钻孔施工关键技术

根据顶板高位定向钻孔快速钻进成孔与工作面卸压瓦斯高效抽采治理需要，针对现有螺杆马达定向钻进技术与分级扩孔方法存在的问题，开展了顶板硬岩定向钻进与大直径扩孔钻进关键技术研究，开发了冲击回转定向钻进技术、扭冲回转定向钻进技术、扭冲旋转扩孔技术以及双级双速扩孔技术等钻孔提速新技术，研制了冲击螺杆马达、矿用小直径扭力冲击器、双级双速螺杆马达、组合式扩孔钻头等配套钻具。综合试验结果表明，硬岩定向钻孔平均机械钻进效率达到8.34 m/h，最高达到13.6 m/h，较常规螺杆马达定向钻进技术提升20%~30%；硬岩大直径扩孔终孔直径达到200 mm，机械钻进效率平均达到5.6 m/h以上，最高达到10.5 m/h。该技术提升了顶板硬岩定向钻进效率与大直径扩孔钻进效率，缩短了顶板高位定向钻孔的综合施工周期，为大直径高位定向长钻孔快速成孔与高效抽采治理回采工作面卸压瓦斯提供了可靠的技术手段。     

The control of paracetamol particle size and surface morphology through crystallisation in a spray dryer

The parameters governing the crystallisation of paracetamol using various conventional techniques has been extensively studied, however the factors influencing the drug crystallisation using spray drying is not as well understood. The aim of this work was to investigate the crystallisation of an active pharmaceutical ingredient through evaporative crystallisation using a spray dryer to study the physicochemical properties of the drug and to use semi-empirical equations to gain insight into the morphology and particle size of the dried powder. Paracetamol solutions were spray dried at various inlet temperatures ranging from 60 °C to 120 °C and also from a series of inlet feed solvent compositions ranging from 50/50% v/v ethanol/water to 100% ethanol and solid-state characterisation was done. The size and morphology of the dried materials were altered with a change in spray drying parameters, with an increase in inlet temperature leading to an increase in particle Sauter mean diameter (from 3.0 to 4.4 µm) and a decrease in the particle size with an increase in ethanol concentration in the feed (from 4.6 to 4.4 µm) as a result of changes in particle density and atomised droplet size. The morphology of the dried particles consisted of agglomerates of individual crystallites bound together into larger semi-spherical agglomerates with a higher tendency for particles having crystalline ridges to form at higher ethanol concentrations of the feed.     

喷淋液滴在空气环境下的运动特性

本文以喷淋液滴在空气环境下运动特性为工程背景，建立单个液滴在常温、常压空气环境中的动量方程，分析液滴沉降特性、追赶特性及运动轨迹行为。计算结果表明，不同喷淋液滴初始条件下，短时间内存在重力大于曳力和重力小于曳力两种情况，但最终减速液滴均会达到受力平衡状态；液滴离开喷淋头后，垂向位移均迅速增大，液滴粒径越大、初始速度越大，垂向位移增长的速率也越大，达到相同位移的用时越短；液滴尺寸、初始速度相差越大，液滴追赶所用的时间越短，追赶位移越小，液滴尺寸、初始速度越接近，液滴追赶所用的时间越长，追赶位移越大；液滴初始速度越大、初始直径越大、喷射角度越大，横向速度消失越慢，达到的横向位移越大，喷射液滴覆盖的面积也越大。计算结果有助于优化工程实际中喷淋系统的设计与布置。     

水平井筒气水流动规律及影响因素

由于流动方向变化及壁面流体的不断径向入流，水平井筒的气水流动规律与常规直井存在较大差异。在总结前人研究结果的基础上，优选水平井筒气液两相预测模型，并在验证模型可靠的情况下，考虑管壁入流和气液流型变化，改变气量、水量、管径、倾角、轨迹波动、气水入流位置等多个影响因素，对水平段流型、压力分布规律及影响因素进行综合预测分析，为水平气井的生产管理及后期措施优化提供依据。研究结果表明，一般生产条件下水平井筒存在分层流、间歇流和环雾流3种流型，管径和倾角对水平井筒的气、水流型影响最为明显，管壁入流对入流就地井筒流态的影响较小。水平井筒压力损失与气量、水量、轨迹上倾角及轨迹波动起伏程度呈正相关性，而与管径和下倾角呈负相关性。预测范围内，气量、轨迹上倾和管径对水平井筒压力损失的影响最为明显，是水平井筒压降的关键影响因素。随着轨迹上倾角增加，水平井筒压降随气量的变化规律发生明显反转，低气量条件下水平井筒压降随气量的减小而增加，高气量下压降随气量增加而增加。     

Manufacture of Multilayered Artificial Cell Membranes through Sequential Bilayer Deposition on Emulsion Templates

Efforts to manufacture artificial cells that replicate the architectures, processes and behaviours of biological cells are rapidly increasing. Perhaps the most commonly reconstructed cellular structure is the membrane, through the use of unilamellar vesicles as models. However, many cellular membranes, including bacterial double membranes, nuclear envelopes, and organelle membranes, are multilamellar. Due to a lack of technologies available for their controlled construction, multilayered membranes are not part of the repertoire of cell-mimetic motifs used in bottom-up synthetic biology. To address this, we developed emulsion-based technologies that allow cell-sized multilayered vesicles to be produced layer-by-layer, with compositional control over each layer, thus enabling studies that would otherwise remain inaccessible. We discovered that bending rigidities scale with the number of layers and demonstrate inter-bilayer registration between coexisting liquid–liquid domains. These technologies will contribute to the exploitation of multilayered membrane structures, paving the way for incorporating protein complexes that span multiple bilayers.