Real-time molecular characterization of air pollutants in a Hong Kong residence: Implication of indoor source emissions and heterogeneous chemistry

Due to the high health risks associated with indoor air pollutants and long-term exposure, indoor air quality has received increasing attention. In this study, we put emphasis on the molecular composition, source emissions, and chemical aging of air pollutants in a residence with designed activities mimicking ordinary Hong Kong homes. More than 150 air pollutants were detected at molecular level, 87 of which were quantified at a time resolution of not less than 1 hour. The indoor-to-outdoor ratios were higher than 1 for most of the primary air pollutants, due to emissions of indoor activities and indoor backgrounds (especially for aldehydes). In contrast, many secondary air pollutants exhibited higher concentrations in outdoor air. Painting ranked first in aldehyde emissions, which also caused great enhancement of aromatics. Incense burning had the highest emissions of particle-phase organics, with vanillic acid and syringic acid as markers. The other noteworthy fingerprints enabled by online measurements included linoleic acid, cholesterol, and oleic acid for cooking, 2,5-dimethylfuran, stigmasterol, iso-/anteiso-alkanes, and fructose isomers for smoking, C₂₈-C₃₄ even n-alkanes for candle burning, and monoterpenes for the use of air freshener, cleaning agents, and camphor oil. We showed clear evidence of chemical aging of cooking emissions, giving a hint of indoor heterogeneous chemistry. This study highlights the value of organic molecules measured at high time resolutions in enhancing our knowledge on indoor air quality.     

消化吸收引进技术 完善化肥工业国产化

本文回顾了我国化肥工业国产化发展过程，论述了实现国产化的条件，并对国产化项目提出了几点建议。     

集成电路芯片信息泄漏旁路分析模型

旁路分析可以绕过对加解密算法的繁琐的分析,通过分析泄漏的信号而获取芯片密码信息。其关键问题在于掌握芯片运行过程中泄漏信息的机理,进而建立统计分析泄漏信号的信息泄漏模型。本文研究讨论集成电路芯片物理信息泄漏的机理,并据此建立了信息泄漏旁路分析模型。     

新型隧道钢环安装机的设计与研究

为实现国内隧道施工中钢环安装的机械化操作,设计了一种新型隧道钢环安装机械.详细介绍了钢环安装机的机械原理及机构自由度的计算,最后利用蒙特卡洛法得出了钢环安装机在隧道径向操作的工作空间.经过实际运作,该安装机满足了管片加固中钢环安装的精确度要求,为相关隧道工程施工拓宽了空间.     

国家中心城市产业集群协同发展模式研究——以西安为例

为满足国家经济高速发展需求,陕西省大力推进以西安国家中心城市为中心的集聚周边城市产业优势与功能的"大西安都市圈"建设.产业集群协同发展作为推动"大西安都市圈"建设进程的重要举措,如何构建合理的产业集群协同发展模式成为急需解决的关键问题.分析产业集群协同发展的必要性及现存问题,在制定产业集群协同发展模式构建标准和定位主体...     

45号钢垫圈断裂的原因分析和改进措施

针对45号钢垫圈在装配后发生断裂的情况,对45号钢垫圈进行断口形貌分析、力学性能分析、化学成分分析和金相组织分析。宏观形貌显示内孔存在加工台阶和明显刀痕,能谱测试发现断裂起始处存在锌元素,金相组织分析确认内孔加工面存在微裂纹。结合加工工艺分析,确认45号钢垫圈的断裂原因,并提出改进措施。     

阀箱开裂分析

阀箱加工后经超声波探伤发现内部异常现象,对其进行了宏观、微观检查和金相分析.结果表明:阀箱由于原材料去氢不充分,致使阀箱内部产生裂纹.     

Genomic data privacy-preserving scheme based on the improved PSI protocol

In order to solve the problem of privacy leakage in the sharing of genomic data, a genomic data privacy-preserving scheme based on the improved Private Set Intersection (PSI) computing protocol is presented, which leverages the Bloom Filter, Cuckoo Hash, and Random Oblivious Transfer (ROT) extension protocol to not only protect the genomic sequence information on the user when detecting a disease-causing gene but also judge whether he or she has some disease factors or not. Moreover, the correctness and security of the proposed scheme in the detection scenario of disease-causing genes are proved in the semi-honest security model. In addition, a series of experiments is conducted to verify the efficiency of the proposed scheme. The results reveal that the running time and communication overhead of the proposed scheme are much less than those of the existing PSI schemes.     

片状形貌Zr-ZSM-5分子筛的合成与表征

碱性体系中以水玻璃和硅溶胶为双硅源,硫酸铝为铝源,在硅铝酸盐凝胶形成过程中加入氧氯化锆,用水热晶化法成功合成了Zr-ZSM-5分子筛。通过XRD、Raman、UV-VIS、BET、SEM、NH3-TPD、Py-IR等手段对其进行表征。研究结果表明:Zr成功进入ZSM-5分子筛骨架,且随着锆摩尔含量的增加,分子筛的比表面积减小,孔径和孔体积增大,势必会影响到分子筛的择形催化性能;此外,分子筛的酸类型重新分布,L酸比例增大,总酸量和酸强度有所减小,势必会影响其酸催化性能;同时分子筛的生长方式也发生了改变,晶体结构由三维棺状变为二维层片状,相对结晶度有所降低,但其骨架结构依然保持完整。