车载天然气水合物储运装置

天然气水合物(NGH)储运技术是一种安全高效且费用较低的储运方法。储运水合物车载装置的出现,为天然气运输又增添了一种选择方式。根据水合物特点,分析了车载装置储运天然气水合物的可行性,介绍了装置的基本结构。NGH储运技术作为一种新式的天然气传输方式,在未来的社会中一定大有可为。     

Conductivity improvement of CuCrO2 nanoparticles by Zn doping and their application in solid-state dye-sensitized solar cells

Undoped and Zn-doped CuCrO₂ nanoparticles were synthesized by sol–gel method as promising wide band gap p-type semiconductor materials for solid-state dye-sensitized solar cells (DSSCs). We studied the influence of Zn dopant concentration on structural, electrical and optical properties of CuCrO₂ nanoparticles. The X-ray diffraction data indicated that the delafossite-to-spinel ferrite phase transition occurs by increasing the amount of Zn doping. The average nanoparticle size was determined about 40 nm. A minimum value of electrical resistivity of 5.7 Ω cm was obtained for doping concentration of 5%. Having optimized the Zn-doped CuCrO₂ nanoparticles, solid-state DSSCs were fabricated using undoped and Zn-doped CuCrO₂ (5%) as solid electrolytes. As the photoanode layer, the vertically aligned TiO₂ nanorod arrays were grown on FTO glass using a hydrothermal method. Compared with undoped CuCrO₂, the Zn-doped nanoparticles exhibited an improvement in photovoltaic properties. The overall efficiency enhancement of 39% was obtained for the dopant concentration of 5%. The improved power conversion efficiency is attributed to the lowered electrical resistivity and enlarged work function of Zn-doped CuCrO₂ nanoparticles.     

自动式圆形弯管内表面精密抛光装置设计

为了解决弯管内表面精密抛光困难的问题,设计了一种弯管内表面自动抛光装置。该抛光装置总体结构由抛光头、绕线机构、传动机构、夹紧机构以及连接机构等部分组成。整个装置与圆截面弯管零件连成一容腔,可向零件内腔充入用于对零件内表面进行抛光加工的抛光液,控制器控制步进电机带动两端的绕线装置工作,从而实现对弯管内表面的精密抛光加工。利用软件Fluent进行流体仿真,仿真结果表明:流体出口的流速很高,使旋转喷射抛光作用发挥得较好,能够很好地对圆形截面弯管内表面进行抛光加工。     

Polydimethylsiloxane Fluidic Device with Polydopamine‐Coated Inner Channel for Production of Uniform Droplets

A polydimethylsiloxane (PDMS)‐based fluidic device with two flow channels is fabricated by using a rapid prototyping method. The PDMS‐based fluidic device is used to produce water‐in‐oil emulsion (W/O) droplets due to its intrinsic hydrophobicity. To produce uniform oil‐in‐water (O/W) emulsion droplets, the inner channel of the PDMS fluidic device is coated with polydopamine (PDA) by flowing a dopamine precursor in the water channel of the fluidic device. The PDA coating is confirmed by an increase in morphological roughness and nitrogen content. In addition, the contact angle of the PDMS surface decreases from 95° to 30° during PDA coating, suggesting that the inner surface of the fluidic device is hydrophilic. Uniform W/O and O/W emulsion droplets are produced by the pristine PDMS and PDA‐coated PDMS fluidic devices, respectively.

     

新一代SiC功率器件及其在逆变焊机中的应用

目前逆变焊机普遍采用的Si基功率器件的性能已接近由其材料特性决定的理论极限,依靠Si基功率器件继续完善和提高逆变焊机性能的潜力已十分有限。SiC是一种革命性的宽禁带半导体材料,是下一代功率半导体材料的重点发展方向。介绍了新型SiC材料的特性及其功率器件的类型、原理和特点;对比分析SiC和普通Si基功率器件的性能;在此基础上探讨将SiC功率器件应用于逆变焊机的优势;分析和展望SiC功率器件在新一代逆变焊机中的应用前景。     

基于AMESim液压冲击钻机行走液压系统建模与分析

液压冲击钻机的行走装置是整机的运行部分,也是整台设备的支承基座,其液压系统的设计合理与否,对整机的性能起着关键性的作用,因此,分析其液压系统性能对于了解机器性能十分必要。研究行走装置液压系统的工作原理,基于AMESim搭建所研究系统的仿真模型,确定仿真参数后,对模型进行仿真分析,获取冲击钻机行走装置液压系统速度特性曲线和各油口的压力特性曲线,对设计进行分析验证,以检验其准确性与合理性,为该类系统的改进设计和行走装置的优化等提供理论依据和研究方法。     

太阳能空气源复合多功能热泵系统的试验研究

构建了一种多功能直膨式太阳能与空气源复合的热泵系统。在常州的冬季及春季分别对试验样机的运行特性进行研究。试验结果表明:系统在冷暖联供的工况下,即同时产生生活热水和冷冻水,整个过程平均COP为6.0;在冬季,太阳辐射强度为354 W/m~2时,系统制生活热水平均COP为4.32;模拟系统供暖,即将循环水从40℃加热至45℃时,测试结果中最低COP为5.07。在春季,太阳辐射强度为856 W/m~2时,系统制生活热水平均COP为5.78。夏季时,系统同时生产冷热水用于生活热水和供冷的需求;冬季时,由于太阳能的辐射,提高了系统的蒸发温度,热泵的性能因此得到提升。     

Ф2800mm旋转锻造工作台研制

旋转锻造工作台是大型锻造液压机组最基本的常用工装具,可完成饼块类锻件的全回转自由锻造镦粗工艺.针对高效灵活、大载荷、高热应力的Ф2800 mm锻造旋转工作台进行研制,通过采用可更换耐高温工艺垫板(上盘)、竖直蝶簧组上浮支承装置、紧凑型回转大轴承、快换液压系统等关键技术,解决了镦粗锻造工艺中大载荷传递、高温锻件热效应防护、紧凑型全回转液压驱动、便捷式快速装拆、高效可靠的机电液系统联动与安全防护等设计难题,应用于80 MN快速锻造液压机组的大负荷、高温工况,获得了工程实践验证,大大缩短了辅助工作时间,提高了“快锻”全环节工作效率.     

Pulsed laser ablation in liquid synthesis of ZnO/TiO2 nanocomposite catalyst with enhanced photovoltaic and photocatalytic performance

In this work, we employed an impurity-free nanoparticle synthesis technique, known as pulsed laser ablation in liquid (PLAL), to integrate titanium dioxide nanoparticles (TiO₂ NPs) into zinc oxide nanorods (ZnO NRs) with varying relative proportions. The main objective of this integration was to enhance the charge carrier separation of photo-generated electron hole pairs during solar irradiation. For the synthesis process, an Nd:YAG laser at 532 nm wavelength was applied as an ablation source, along with deionized water as a solvent medium in which the precursor materials were dispersed prior to laser irradiation. The nanocomposites were characterized by X-ray diffraction (XRD), UV–vis absorption and in-situ Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR-TEM) and field emission scanning electron microscopy (FE-SEM). The synthesized nanocomposites were primarily utilised in two applications: firstly, as a catalyst in the degradation of methyl orange (MO) and secondly, as photo-anode in dye sensitized solar cell (DSSC). Our research has demonstrated that optimal performance was obtained for the nanocomposite containing 10% and 90% (by weight) TiO₂ NPs and ZnO respectively, which we define as the ideal nanocomposite. Relative to pure ZnO, the photo-conversion efficiency of the ideal composite was improved substantially by 63.73%, whilst the photo-degradation rate was enhanced by 3 fold. The oxidation state and the microstructural of the segregated ideal nanocomposite confirms that oxygen vacancy defects were created when perfect surface integration occurs between TiO₂ and ZnO. Nonetheless, we believe that the performance enhancement is predominantly due to the excellent charge carrier separation and fast interfacial electron flow in this nanocomposite.     

新型磁流变刹车装置设计与性能研究

设计了一种兼顾盘式与筒式结构优点的新型磁流变刹车装置,采用Maxwell软件结合田口算法思想对结构进行仿真优化。搭建实验测试平台,测试了磁流变液刹车装置的静态以及动态性能,验证了所设计的结构是有效的,实验结果达到预期目标,建立了制动力矩与输入电流的关系式,修正了τ-H经验公式,修正后的理论计算值与测量值基本一致,验证了磁流变液在高速剪切情况下存在剪切变稀的现象。