操作窗口对排风柜污染物控制效果影响的实验研究

为提升排风柜的控污能力,在排风柜性能测试实验台上,采用示踪气体测试法和正交试验法,研究了操作窗口竖直开度、水平开度、面风速和操作窗口位置对排风柜前呼吸区污染物控制效果的影响。极差分析和方差分析结果表明:各因素对呼吸区污染物控制效果影响的强弱顺序依次为竖直开度、水平开度、面风速、操作窗口位置;操作窗口水平开度、竖直开度增大,排风柜对呼吸区的污染物控制效果减弱;面风速增大,控制效果增强;水平开度与竖直开度对控制浓度的影响存在较大的相关性,这2个因素对控制浓度的影响仅在另一因素达到一定水平后才能体现。     

In Vivo Silencing of Genes Coding for dTip60 Chromatin Remodeling Complex Subunits Affects Polytene Chromosome Organization and Proper Development in Drosophila melanogaster

Chromatin organization is developmentally regulated by epigenetic changes mediated by histone-modifying enzymes and chromatin remodeling complexes. In Drosophila melanogaster, the Tip60 chromatin remodeling complex (dTip60) play roles in chromatin regulation, which are shared by evolutionarily-related complexes identified in animal and plants. Recently, it was found that most subunits previously assigned to the dTip60 complex are shared by two related complexes, DOM-A.C and DOM-B.C, defined by DOM-A and DOM-B isoforms, respectively. In this work, we combined classical genetics, cell biology, and reverse genetics approaches to further investigate the biological roles played during Drosophila melanogaster development by a number of subunits originally assigned to the dTip60 complex.     

Effect of the Wet Outlet Geometry on the Shockwave Position in Supersonic Separators

Supersonic separators (3Ss) are applied in gas separation processes. Two-dimensional simulation is employed to investigate the effect of operational and thermophysical parameters on the shockwave position. In addition, the impact of the cyclonic part and wet outlet geometry is evaluated by proposing four cases. Increasing the length of the cyclonic part exerts positive and negative influences on the performance of the 3S and the pressure recovery coefficient, respectively. The optimum length is determined between 10 and 15 cm. To demonstrate negative effects of wasted air from the wet outlet, its flow has been increased from 3.6 to 8.1 % of the inlet flow. Improved performance of the 3S is obtained by reducing the flow disturbances around the wet outlet and moving the shockwave towards the outlet.     

基于增强现实的硬件维护系统研究与设计

传感器、多媒体、机器学习等技术的快速发展,促进了增强现实在多领域得到普及和应用。航空设备硬件运行维护也是一个重要领域,可以基于增强现实构建一个硬件维护系统,渲染一个虚拟的硬件运行环境,模拟实际的故障发生情况,加强对硬件设备的装配和维修,进一步提高航空设备硬件运行维护的水平。本文详细地描述了增强现实在硬件维护系统中的应用功能,分别是虚拟环境仿真功能、装配维护功能、3D模型设计功能,同时构建一个强大的硬件维护系统,该系统沉浸感强、娱乐性足,能够激发硬件维护人员的学习和应用兴趣,具有重要的作用和意义。     

添加剂对航空润滑油橡胶相容性的影响

采用满足MIL-PRF-23699F规范中航空发动机润滑油要求的季戊四醇酯为基础油，研究了3种抗氧剂和3种极压抗磨剂对航空润滑油橡胶相容性的影响。结果表明：磷酸酯极压抗磨剂使丁腈橡胶的体积变化率增大，其他添加剂对丁腈橡胶的体积变化率无显著影响；极压抗磨剂对氟橡胶的体积变化率几乎没有影响，而抗氧剂使氟橡胶的体积变化率有微弱的减小；胺类添加剂在酯类润滑油中对氟橡胶拉伸性能无显著影响；酸性磷酸胺极压抗磨剂使硅橡胶体积发生收缩，使氟硅橡胶的体积变化率减小；酸性磷酸胺极压抗磨剂与硅橡胶和氟硅橡胶可发生化学反应，使橡胶的拉伸性能大幅下降。     

The influence of light on the chroma of aviation kerosene

Influence of light on the chroma of low pressure hydrogenation aviation kerosene was studied using different lights (ultraviolet light, infrared light, sunlight and no light) in the same environment full of oxygen. UV light with short wavelength has the largest influence. Coloring substances were isolated by adsorption on neutral alumina followed by ether extraction and identified by using infrared spectrum, elemental analysis and two-dimensional GC-MS. Oxygen-containing compounds are main coloring substances. Light can provide the required energy to convert unsaturated hydrocarbons and heteroatom compounds to phenols, quinones and ketones.     

Shotgun metagenomics of dust microbiome from flight deck and cabin in civil aviation aircraft

Microbial exposure is related to the health of passengers on commercial aircraft, but no studies characterized the microbial composition at the species level and identified their ecological determinants. We collected vacuum dust from floor and seat surfaces in flight decks and cabins of 18 aircraft, and amplification-free shotgun metagenomics was conducted to characterize the microbial composition. In total, 7437 microbial taxa were identified. The relative abundance for bacteria, eukaryote, viruses, and archaea was 96.9%, 1.8%, 0.3%, and 0.03%, respectively. The top bacterial species mainly derived from outdoor air and human skin included Sphingomonas, Corynebacterium, Micrococcus luteus, Variovorax paradoxus, Paracoccus dentrificans, and Propionibacterium acnes. The abundance of NIAID-defined pathogens was low, accounted for only 0.23% of total microbes. The microbial species and functional composition were structured by the indoor surface type (R² = 0.38, Adonis), followed by the manufacturer of the aircraft (R² = 0.12) and flight duration (R² = 0.07). Indoor surfaces affected species derived from different habitats; the abundance of dry skin and desiccated species was higher on textile surfaces, whereas the abundance of moist and oily skin species was higher on leather surfaces. The growth rates for most microbes were stopped and almost stopped.     

Emotions and caring mediate the relationship between knowledge of sustainability and willingness to pay for greener aviation

Sustainable initiatives continue to be a major focus of worldwide industries, and this has also become relevant within the aviation industry. As the move to incorporate and switch to sustainable practices increases, the question becomes whether passengers will be willing to pay more for sustainable aviation. Building upon prior research, the purpose of the current study was to identify which factors act as significant mediators between a participant's general knowledge of sustainability, their aviation-specific knowledge of sustainability, and their willingness to pay for greener aviation. Two significant mediators, caring and happiness, were found to explain the relationship between both independent variables and willingness to pay. These findings support the idea that the relationship felt toward sustainability is one that is largely connected through and explained by emotions and how much people care about sustainability. The paper concludes with a discussion of the findings and the practical applications of these results.     

电液位置伺服系统的稳定性分析与应用

介绍了电液伺服控制系统的一般原理及其在钢铁工业中的应用。用于带钢的位置伺服系统，其稳定性的要求是很高的。通过滞后校正环节保证系统的稳定性。利用波德图对系统进行稳定性分析。     

精密定位工作台的定位精度标准分析对比

通过对定位精度的国际标准ISO 230-2、德国标准VDI/DGQ3441、美国标准NMTBA的对比,分析它们对于定位精度不同的评定和计算方法,并给出在精密定位系统的定位精度计算实例.