Conventional methods for assessing diesel oxidation stability often lack real-time monitoring capability and quantitative precision. This study investigates the evolution of dielectric spectra during diesel oxidation and the predictive efficacy of dielectric difference spectra for oxidation stability indicators. Using a self-developed dual-channel differential dielectric spectrometer based on the AD5933 chip and an oxidation stability tester, the oxidation of 19 diesel samples from various Chinese refineries was accelerated under controlled conditions (140 °C, 700 kPa oxygen). The dynamic changes in the real (ε') and imaginary (ε″) parts of the dielectric spectra during oxidation were tracked. The results reveal that the low-frequency response (<20 kHz) is governed by ionic conduction and interfacial polarization, whereas the high-frequency region (>50 kHz) primarily reflects dipole relaxation behavior. The dielectric parameters (ε' and ε″) of all oil samples exhibited continuous and regular changes with oxidation progression, without abrupt transitions. Dielectric responses showed significant variations in the low-frequency region, a finding consistently supported by the characteristic relaxation patterns in Cole-Cole plots. The introduction of exogenous polar substances (e.g., water) markedly interfered with relaxation characteristics. Although the current measurements were conducted offline, the methodology demonstrates potential for future adaptation to online monitoring systems. As a key advancement over previous work, this study integrated dielectric difference spectroscopy with dynamic principal component-based partial least-squares regression to predict key oxidation stability indicators (filterable insolubles at 140 °C, induction period, and oxidation inflection point). The use of difference spectrum (Δε) enhances the sensitivity to spectral changes induced by oxidation. Predictive models based on the imaginary part of the difference spectrum (Δε″) achieved outstanding performance, with correlation coefficients (R) of 0.9778, 0.9786, and 0.9581 for the three indicators, respectively. This research provides apromising methodological foundationfor thefuture development of real-time, nondestructive monitoring of fuel oxidation and holds significant potential for the online assessment of fuel quality.

In our prior research (2022), a Fe3O4@PDA@Au@GO composite was reported as a surface-enhanced Raman scattering (SERS) substrate for phenanthrene detection, with a detection limit of 10−7 g/L. The current study is a mechanistic follow-up investigation, which aims to explore the enhancement and enrichment mechanisms of the same substrate. By integrating density functional theory (DFT) calculations, adsorption experiments, and spectroscopic analyses (Raman, FTIR, XPS) before and after adsorption, the surface enhancement mechanism of the Fe3O4-PDA-Au-GO composite substrate is investigated. Our findings suggest that Fe3O4 enables efficient magnetic separation. The polydopamine (PDA) modification layer appears to enhance the uniformity and stability of the substrate surface, which is beneficial for uniform loading of Au nanoparticles (Au NPs). Graphene oxide (GO) and PDA are found to contribute to the effective enrichment of phenanthrene. Au NPs (mostly in the metallic Au0 state) may provide electromagnetic enhancement through localized surface plasmon resonance, and may also contribute to chemical enhancement through possible interactions with phenanthrene. Overall, the stepwise comparison presented in this study is consistent with the proposed roles of Au and GO in enhancing the SERS performance, which collectively improve the detection sensitivity.

In order to achieve rapid detection of oil quality, an innovative small-scale oil joint detection system is designed in this paper. The joint detection system combines a micro-distillation instrument and Raman spectrometer module through a combination module. The basic principle is to use a Raman spectrometer to detect the distillate in the micro-distillation instrument in order to predict the properties of the oil and determine its quality. The system uses Savitzy-Golay smoothing, baseline correction, normalization processing, partial least squares, and other methods for data fitting to ensure the authenticity and comparability of the measured data. Fourteen different sources and grades of diesel oil are selected in this paper for pre-experiments to verify the data fitting effect. Two oil samples, No. 1-10# diesel oil 1 with strong fluorescence interference and No. 2-10# diesel oil 2 with weak fluorescence interference, were used as test objects to compare the Raman spectra of undistilled oil and distilled oil, verify the testing effect of the joint detection system, and analyze the mechanism of fluorescence interference mainly existing in the heavy components of the oil. The test results show that the joint detection system can quickly detect the quality of different grades of diesel oil, with good smoothness, obvious characteristic bands, and good data fitting. The joint detection system designed in this paper has the advantages of high sensitivity, high integration, and small size, laying the foundation for research related to distillation ranges combined with Raman spectroscopy technology.

This study focuses on the preparation of a highly active surface-enhanced Raman spectroscopy (SERS) substrate, where Ag nanoparticles synthesized by the Lee–Meisel method are loaded onto the surface of GO@PVP nanoparticles through classical electrostatic attraction. The substrate was characterized by SEM and XPS analysis. The SERS-active substrate was utilized for the detection of phenanthrene in aqueous solutions, achieving a detection limit of 10−8 g/L (5.6 × 10−11 mol/L). In comparison to conventional Raman spectroscopy, this method exhibits a significant reduction in the detection limit and holds promise for trace polycyclic aromatic hydrocarbons (PAHs) monitoring in environmental samples.

Based on the concept of microscale chemical experiment, combined with the characteristics of POL testing experiment, this paper takes the distillation range determination experiment of petroleum products as the object, and constructs the POL testing experiment system of sample microscale and instrument miniaturization.The experiment system has the characteristics of small sample consumption, short single experiment time, flexible parameters setting of experimental conditions, and efficient monitoring and feedback of the experimental process.It solves the problems of large sample consumption, long experimental process, difficult recovery and treatment of ’three wastes’ in the experimental teaching process, and inability to timely and effectively monitor and feedback the experimental process. Based on the microscale distillation range measurement experimental system, scientific research experiments on the evaporation performance of petroleum products can be carried out.

针对油料化验实验教学过程中存在的实验过程监控及教学效果反馈难等系列矛盾问题,构建了基于虚拟仪器的油料化验实验系统,该系统将油料化验所涉及到的化验项目归类总结为 8 种类型,并据此将所用到的化验仪器设备区分为 9 个模块,基于虚拟仪器软件和硬件系统实现了具备35个化验项目的油料化验实验系统.

In this study, highly active Fe3O4@PDA@Au@GO surface-enhanced Raman spectroscopy (SERS) active substrate was synthesized for application in the enrichment and detection of trace polycyclic aromatic hydrocarbons (PAHs) in the environment. The morphology and structure were characterized by transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD) and UV–visible absorption spectrum (UV–vis spectra). The effect of each component of Fe3O4@PDA@Au@GO nanocomposites on SERS was explored, and it was found that gold nanoparticles (Au NPs) are crucial to enhance the Raman signal based on the electromagnetic enhancement mechanism, and apart from enriching the PAHs through π–π interaction, graphene oxide (GO) also generates strong chemical enhancement of Raman signals, and polydopamine (PDA) can prevent Au from shedding and agglomeration. The existence of Fe3O4 aided the quick separation of substrate from the solutions, which greatly simplified the detection procedure and facilitated the reuse of the substrate. The SERS active substrate was used to detect phenanthrene in aqueous solution with a detection limit of 10−7 g/L (5.6 × 10−10 mol/L), which is much lower than that of ordinary Raman, it is promising for application in the enrichment and detection of trace PAHs.

我院贯彻落实新时代军事教育方针,提出"双重"建设,着力建设重点院校和重点专业.课程建设之一慕课,是实现"双重"的重要途径.本文在"双重"背景下,探讨《油料化验》慕课建设背景意义、课程目标和课程内容设计、课程视频制作及运行等.提出课程内容设计具有粘性的几点方法,并对课程进行混合式教学模式的应用与实践,提高了《油料化验》课程的教学效果,促进了油料化验员职业技能鉴定水平,提高学员的实操技能及岗位适应能力要求.

The stratified oil-water two-phase flow is commonly encountered in offshore oil production systems, and is considered to be among the fundamental flow configuration in two-phase systems. A numerical quasi-three dimensional model for the calculations of the axial pressure gradient, interface height, water holdup, and the flow field in a fully developed oil-water two-phase stratified pipe flow has been developed. The oil-water curved interface configuration is predicted by using minimum energy model. The model solves the governing equations of the steady axial momentum and mass conservation equations together with a low Reynolds number k～ε model of turbulence for the eddy viscosity, performed in the bipolar coordinate system, for convenient describing the curved interface and mapping of the physical domain. The predicted dynamic parameters, such as interface height of close to the pipe wall and in the middle of the pipe cross-section, water holdup, pressure gradient and flow filed are compared with the experiments. At the same time, this model is utilized to study the variation of these dynamic parameters with increasing superficial oil and water velocities. In addition, the numerical model with concave oil-water interface gives more accurate results than a flat interface. It indicates that the interfacial configuration effects are significant.

通过使用Metage Opal 2800便携式拉曼光谱仪并以银溶胶作为SERS基底来快速检测水溶液中多环芳烃菲、蒽的质量浓度并探索水溶液中菲、蒽的检测限.采用便携式拉曼光谱仪作为检测仪器,以银溶胶作为SERS基底检测水样品中不同质量浓度多环芳烃菲、蒽并进行图谱分析,得到检测限分别是10-7 g·L-1、10-6 g·L-1;该方法简便、灵敏、快速,对下一步Metage Opal 2800便携式拉曼光谱仪现场检测废水具有重要意义.

在自配抗氧剂测定溶液体系(丙酮/水(V/V)为10:1,高氯酸锂浓度为0.1 mol/L)下,使用Ruler仪器与Autolab电化学工作站PGSTAT101仪器,对含有不同比例抗氧剂的模拟油样进行抗氧剂含量测定.结果表明自配溶液体系用于伏安法测定抗氧剂含量具有可行性,为替代Fluitec公司绿色瓶试剂提供理论依据.

A method for surface-enhanced Raman spectroscopy (SERS) sensing of polycyclic aromatic hydrocarbons (PAHs) is reported. Fe3O4@PDA@Ag@GO is developed as the SERS substrate prepared by classical electrostatic attraction method based on the enrichment of organic compounds by graphene oxide (GO) and polydopamine (PDA) and the good separation and enrichment function of Fe3O4. The morphology and structure of the SERS substrate were represented by transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD) and the UV–visible absorption spectrum (UV–vis spectra). The effect of different temperatures on SERS during synthesis was investigated, and it was found that the best effect was achieved when the synthesis temperature was 90 °C. The effect of each component of Fe3O4@PDA@Ag@GO nanocomposites on SERS was explored, and it was found that Ag NPs are of great significance to enhance the Raman signal based on the electromagnetic enhancement mechanism; apart from enriching the polycyclic aromatic hydrocarbons (PAHs) through π–π interaction, GO also generates strong chemical enhancement to the Raman signal, and PDA can prevent Ag from shedding and agglomeration. The existence of Fe3O4 is favored for the fast separation of substrate from the solutions, which greatly simplifies the detection procedure and facilitates the cycle use of the substrate. The experimental procedure is simplified, and the substrate is reused easily. Three kinds of PAHs (phenanthrene, pyrene and benzanthene) are employed as probe molecules to verify the performance of the composite SERS substrate. The results show that the limit of detection (LOD) of phenanthrene pyrene and benzanthene detected by Fe3O4@PDA@Ag@GO composite substrate are 10−8 g/L (5.6 × 10−11 mol/L), 10−7 g/L (4.9 × 10−10 mol/L) and 10−7 g/L (4.4 × 10−10 mol/L), respectively, which is much lower than that of ordinary Raman, and it is promising for its application in the enrichment detection of trace PAHs in the environment.

针对传统石油产品闪点测试方法耗时长、操作繁琐、危险系数大的缺点,提出了一种基于差压式微量快速蒸馏技术的石油产品闭口闪点无点火式测试系统。首先,利用该测试系统获取待测样品的蒸汽温度-压力变化曲线,对曲线进行归一化积分计算;其次,利用偏最小二乘法建立校正集样品曲线和标准闪点值之间的多元校正模型;最后,代入未知样品的蒸汽温度-压力曲线计算其闭口闪点。选取10种来自不同炼油厂、沸点在20～400℃范围内的石油产品,利用留一法进行验证计算,待测样品闭口闪点预测计算值平均绝对误差为0.33℃,平均相对误差为3.4%,表明该测试系统可以对石油产品闪点进行有效地预测,与采用GB/T 261标准方法测定的闪点实测值吻合较好。

Wax precipitation and deposition are serious flow assurance problems. Wax precipitation is investigated simultaneously using centrifugation and high-temperature gas chromatography (C-HTGC) to obtain the amount and component distribution of precipitated wax in artificial waxy oil and diesel at different temperatures. However, the conventional C-HTGC method gives upper measurements of the amount of precipitated wax, as it ignores wax dissolved in crude oil in the centrifugal cake. A modified C-HTGC method was developed to obtain the precipitated solid fraction of crude oil, based on the mass balances of the non-crystallized fraction of the centrifuged cake. The weight, percent and carbon number distribution of precipitated solid wax crystals at different temperatures of artificial oil and 0# diesel were obtained. It was found that wax precipitation characteristics are affected by many factors, including the carbon number distribution of the oil, the sensitivity of alkane crystallization to temperature and the temperature of the waxy oil solution. The average carbon number of alkanes in precipitated wax crystals decreases with the decrease in temperature. The distribution of alkanes in solid wax crystals is roughly the same as that in 0# diesel but slightly heavier than in diesel. Alkanes with high carbon numbers precipitate simultaneously with those with low carbon numbers.

为了提高高硫柴油蒸馏精度检测能力,提出基于拉曼光谱的高硫柴油蒸馏精度自动检测方法.构建高硫柴油蒸馏液的光谱信息采样模型,结合信号频谱特征分析方法进行高硫柴油蒸馏精度特征参数分析,构建高硫柴油蒸馏精度参数辨识和统计分析模型,通过拉曼光谱的强度和平稳性特征量建立高硫柴油蒸馏精度检测的统计特征量,采用线性反馈均衡方法进行高硫柴油蒸馏拉曼光谱信号输出稳定性测试,通过射频标签识别的方法进行高硫柴油蒸馏输出光谱自动识别,结合光谱强度和饱和度实现对高硫柴油蒸馏精度的优化检测.实验结果表明,采用该方法进行高硫柴油蒸馏精度检测的准确性较好,高硫柴油蒸馏参数估计的精度在高硫柴油蒸馏过程控制中具有很好的应用价值.

液体燃料是指能产生热能或动能的液态可燃物质,常用的液体燃料是由石油炼制而成.馏程是石油产品的重要特性,是评价液体燃料蒸发和性能的重要指标,对液体燃料的储存和运输以及用油发动机的安全运行具有重要意义,对燃油产品的生产也具有一定的指导作用.本文主要从馏程检测的发展现状、馏程在燃油质量分析中的应用和改进馏程检测方法3个方面出发,重点综述了馏程与燃油其他检测指标的关联,描述了利用色谱、中红外光谱和拉曼光谱等近年来的新兴技术进行馏程检测,提出了针对新的技术手段的改进与建议,为今后利用馏程进行燃油质量分析提供了参考和借鉴的思路.

针对传统的军用燃料消耗检测系统存在的检测精度低的缺点,设计一种基于拉曼光谱的军用燃料消耗自动检测系统.首先,通过采集模块、传输模块、数据处理和分析模块,设计系统的总体框架;在此基础上,通过采集器、探测器、激光器、拉曼光谱仪和计算机等,完成系统硬件设计;通过WiRE软件完成拉曼数据的采集,采用标准正态变量变换方法对拉曼光谱信号去噪,采用导数法校正谱图基线,利用拉曼分析软件中的标准曲线结合谱图对军用燃料消耗分析和计算,完成系统软件设计,至此完成基于拉曼光谱的军用燃料消耗自动检测系统的设计.通过对比实验,与传统的军用燃料消耗自动检测系统作对比,实验结果表明,采用提出的基于拉曼光谱的军用燃料消耗自动检测系统,得到的检测结果的精度更高,能够更为有效地完成军用燃料消耗的检测.

文章基于Ruler电化学仪器,采用线性扫描伏安法,优化了汽轮机油中的抗氧剂含量测定试验条件,研配了伏安法抗氧剂测定溶液体系.实验表明,当其他实验条件不变,溶剂丙酮/水(v/v)为10∶1,高氯酸锂浓度为0.1mol/L时,实验的重复性和稳定性最好.

为了解决传统航天器姿态测量方法中存在的误差率高的问题,提出基于精密星敏感器的航天器高精度姿态测量标定方法;首先对使用的精密星敏感器进行设计,并将在不影响航天器运行的前提下安装在合适的位置上;通过建立运动坐标系、坐标参数转换和设置姿态参数三个步骤得出航天器运动模型,在该模型下分析出航天器姿态的基本运动规律、利用精密星敏感器识别并选取航天器空间下的任意三个星点,最后综合定位的星点和航天器姿态的运动规律,从不同的角度上确定航天器姿态测量结果,为了提高航天器姿态测量结果的精度进行标定处理;通过模拟实验分析得出结论:与传统测量方法相比,基于精密星敏感器的航天器高精度姿态测量标定方法的平均误差率降低了6.0％.

In this article, a Raman spectroscopy classification method combining the fluorescence background rejection based on graphitized carbon black (GCB) preprocessing and modified hierarchical clustering analysis (HCA) has been put forward, by which 39 fuel samples have been classified correctly and automatically into six types of 0# automobile diesel fuel, 0# general diesel fuel, 97# gasoline, 93# gasoline and 3# jet fuel. GCB preprocessing, during which 50mg GCB is used to filter 0.75 mL fuel sample once, has no influence on those samples which have no fluorescence background such as 3# jet fuels and gasolines and can reject effectively the weak fluorescence background of gasoline and automobile diesel fuel samples and strong fluorescence background of gasoline and general diesel fuel samples. Firstly, the Procrustes distance in the Procrustes analysis (PA) was adopted to measure the similarity between the samples for the classical HCA which was regarded as the modeling stage in the modified HCA algorithm. And the centroid vectors belonging to the different clusters were calculated according to the results of the HCA. Secondly, the types of the unknown test samples could be determined by calculating and comparing the Procrustes distances between the test samples and the centroid vectors of the clusters. The "leave-one-out" cross validation results based on the 39 samples belonging to 6 classes have shown that the GCB preprocessing is an effective fluorescence rejection method for Raman spectra of light fuels which can be applied to qualitative and quantitative analysis.