Protonated acetone ion chemical ionization time-of-flight mass spectrometry for real-time measurement of atmospheric ammonia

Ammonia (NH₃) is ubiquitous in the atmosphere, it can affect the formation of secondary aerosols and particulate matter, and cause soil eutrophication through sedimentation. Currently, the use of radioactive primary reagent ion source and the humidity interference on the sensitivity and stability are the two major issues faced by chemical ionization mass spectrometer (CIMS) in the analysis of atmospheric ammonia. In this work, a vacuum ultraviolet (VUV) Kr lamp was used to replace the radioactive source, and acetone was ionized under atmospheric pressure to obtain protonated acetone reagent ions to ionize ammonia. The ionization source is designed as a separated three-zone structure, and even 90 vol.% high-humidity samples can still be directly analyzed with a sensitivity of sub-ppbv. A signal normalization processing method was designed, and with this new method, the quantitative relative standard deviation (RSD) of the instrument was decreased from 17.5% to 9.1%, and the coefficient of determination was increased from 0.8340 to 0.9856. The humidity correction parameters of the instrument were calculated from different humidity, and the ammonia concentrations obtained under different humidity were converted to its concentration under zero humidity condition with these correction parameters. The analytical time for a single sample is only 60 sec, and the limit of detection (LOD) was 8.59 pptv (signal-to-noise ratio S/N = 3). The ambient measurement made in Qingdao, China, in January 2021 with this newly designed CIMS, showed that the concentration of ammonia ranged from 1 to 130 ppbv.     

Optimization via response surface methodology of the synthesis of a dust suppressant and its performance characterization for use in open cut coal mines

To relieve dust pollution in open cut coal mines and reduce the hazards of coal dust pollution to the environment and workers we optimized the synthesis of a dust suppressant by graft copolymerization of environmentally friendly soy protein isolate with methyl methacrylate. This dust suppressant could effectively control dust pollution in open cut coal mines. The optimized conditions for graft copolymerization in this case were determined by a response surface experiment designed with Design-Expert 10 software. Characterization by scanning electron microscopy showed a significant morphology change of the dust suppressant and the generation of a rigid and dense layer on its surface after interacting with coal dust. The layer exhibited good bonding and dust suppression performance. The analysis with Fourier-transform infrared spectroscopy revealed the appearance of new absorption peaks near 1300, 1072, and 1631 cm⁻¹, demonstrating effective graft copolymerization. The proposed dust suppressant exhibited excellent wind erosion resistance, with a resistance that exceeded 90% at a wind speed of 6.5 m/sec. The successful graft copolymerization and effective bonding and curing of the dust suppressant on coal dust were experimentally verified. This is of great significance to the control of coal dust pollution.     

用于环境检测的智能窗户装置研究

本文研究了一种可以检测环境中一氧化碳浓度、风速、温度和湿度等参数空气质量,由窗体、窗框、电源模块、传感检测模块、无线通讯模块、控制模块、电机传动模块和位置检测模块等组成,能自动开启和关闭,实现通风或者封闭功能的智能窗户装置。     

判决反馈自适应滤波应用于CDMA系统中的单频干扰抑制

针对扩频接收机中窄带干扰抑制中已有结构和算法的优缺点，提出一种在滤波器输入和权值修正中均利用判决值的判决反馈方案，并对常规、采用软判决和采用硬判决三种情况的单边预测型结构和常规最小均方误差（ＬＭＳ）算法、可变步长ＬＭＳ（ＶＳＳ）算法和变步长变动量因子ＬＭＳ（ＶＳＶＭＳ）算法三种算法进行了计算机模拟。结果表明，此判决反馈方案对抑制单频干扰在性能上比已有结构有明显改进，且软判决比硬判决性能略优，算法以     

NM93C46EEPROM及其在M68HC05单片机上的应用

本文介绍用Ｍ６８ＨＣ０５单片机对ＮＭ９３Ｃ４６串行ＥＥＰＲＯＭ进行操作的软硬件技术及读写程序设计的三种方法     

基于灰色预测理论的瓦斯传感器自校正技术

笔者提出了将灰色预测理论与单片机技术相结合 ,对瓦斯传感器的非线性进行自校正的新思路 ;采用了灰色预测理论中GM(1,1)模型和单片机技术相结合 ,将预测误差值对传感器的实测值进行分段补偿的方法 ,实现对瓦斯传感器的非线性自校正 ;该方法克服了灰色预测理论对波动较大的随机序列的预测精度低的缺陷。其研究结果表明 ,应用该方法得到的预测值与真值的拟合程度好 ,预测值与真值之间最大的差值为 0 .15 0 1% ,而该处校正前的差值为 0 .30 0 0 % ,提高了传感器的测量精度。     

双起电方式静电电荷衰减测试仪

在分析了静电电荷衰减测试原理的基础上,提出了以AT89C51单片机为核心组成测试系统,来实现测试自动化的设计方案,设计了具体的硬件结构,重点阐述了测试仪的高压源,信号调理电路,A／D转换电路等的实现,并采用C51进行软件编程。该测试仪工作可靠,具有良好的测量精度和灵敏度,实现测试自动化的同时,很好地提高了测试的准确性。     

单分子荧光技术与聚合物单链物理性质的研究

对以荧光关联光谱、荧光光子计数直方图技术、单分子荧光成像、单分子荧光散焦成像等单分子荧光技术为主要研究手段开展的关于聚合物单分子链物理化学性质的研究工作进行了总结与介绍,重点介绍了本实验室在聚电解质单链构象转变及抗衡离子分布、表界面聚合物单链动态性质、空间受限状态下聚合物单分子链及单分子链段的平动扩散、转动运动的研究工作。研究结果表明,单分子荧光技术在研究高分子单链物理化学方面具有很大的潜力,发展新的技术与方法能够大力促进我们对于高分子体系微观结构与性质的理解与认识。     

铁屑内电解法处理EDTA溶液中络合铜离子

采用批式试验和现代仪器分析研究了铁屑内电解法处理EDTA溶液中络合铜离子,考察了溶液浓度、溶液pH、温度和铁屑粒径等因素对铜离子去除过程的影响.结果表明,铜离子去除过程符合表观一级动力学方程.在pH 2.0～11.0范围内,pH值越低越利于铜离子去除;在酸性条件下溶液pH随内电解进行升高,在碱性条件下溶液pH随内电解进...     

瓶级聚酯切片静电起电特性试验研究*

为了分析瓶级聚酯切片（PET）生产过程中分析筛处理量对其静电带电特性的影响,基于颗粒振动摩擦带电模拟试验,研究单颗粒PET振动摩擦带电饱和量以及多颗粒PET振动带电荷质比数据。结果表明:瓶级PET产品静电半衰期超过80 ks;PET单颗粒与金属分析筛碰撞摩擦时带电量随振动时间增加趋于饱和,且单粒子荷质比大小可超过16 nC·g-1;随着分析筛内PET总质量增加,PET颗粒间碰撞几率增加,但PET的荷质比值迅速降低。利用工业振动筛处理PET时,应尽量提高总颗粒处理量以控制颗粒带电,抑制静电对粉尘吸附作用,有利于脱除切片中携带的粉尘。