便携式飞行时间质谱仪的研制及其在石化污水系统挥发性有机物监测中的应用

近年来，国内的大气污染问题越来越严重，挥发性有机物（VOCs）的排放是其中一个重要原因。VOCs是臭氧和气溶胶的前驱物之一，在大气化学反应过程中扮演着极其重要的角色。本实验自行研制了一台基于真空紫外（VUV）灯的高分辨光电离飞行时间质谱仪（TOF MS），建立了一种新的VOCs稀释采样方法，并将其应用于石化行业污水处理系统VOCs的采样与分析。结果表明：隔油系统的3个池子基本没有测到高浓度的挥发性有机物，其中溶气气浮甲苯物质的质量浓度最高，为50.41 mg/L，其余组分的质量浓度大多数在0.1~1.0 mg/L之间；1#加氢和2#加氢隔油池有着类似的组分浓度，以1#加氢隔油池为例，二甲苯物质的质量浓度为10.60 mg/L，乙苯为52.33 mg/L，苯为59.80 mg/L；由于罐区隔油池没有加盖，处于露天状态，挥发性有机物气体容易向大气中扩散，并没有检测出较高浓度组分。可以看出，新式采样方法可有效地稀释定量样品，操作简便，减少了样品因闪蒸过程造成的VOCs损失，检出物质更丰富；同时，使用自行研制的TOF MS仪器能够快速检测不同装置污水处理系统的VOCs种类，将该仪器用于实际样品检测，发现化工企业大多数密闭的池子都含有苯系物、醚类等，但不同工艺的污水处理系统VOCs存在明显差异。该质谱仪适用于石化企业污水系统VOCs监测。     

悬浮于润滑油中的颗粒运动分析及其对油膜压力的影响

对含有固体颗粒的局部润滑流域建立格子Boltzmann(LBM)离散模型,分析固体颗粒在润滑油中的动力学特性;考虑颗粒形状的影响,推导计入单个固体颗粒运动的润滑方程,并分析得到油膜压力;将油膜流动特性与颗粒动力学计算相结合,分析不同形状的颗粒运动对于油膜压力的影响。分析发现,当颗粒进入润滑油后,经过很短的瞬时颗粒就会达到一个瞬态稳定的状态,无论颗粒在油膜厚度方向的初始位置位于两壁面之间的中线上侧还是下侧,颗粒都会向中线位置移动;当颗粒速度为0时对于油膜压力的影响较大,随着颗粒速度逐渐增大,颗粒对于油膜压力的影响逐渐减小;当颗粒的宽度在油膜厚度方向相同时,长宽比越大的颗粒对于油膜压力的影响也越大;当颗粒长轴相等时,颗粒在油膜厚度方向的宽度越大,则其对于油膜压力的影响也越大,即颗粒形状对于油膜流动的阻碍能力越强,则其对于油膜压力的影响越大。     

基于改进K-Means聚类和误差反馈的数据清洗方法

综合能源数据的采集与分析是构建综合能源系统的基础和前提，由于数据采集过程中存在系统故障、线路检修等随机因素的制约，其数据常存在异常和缺失情况。为解决上述问题，提出了基于改进K-Means聚类和误差反馈的数据清洗方法，对异常数据进行识别和插补。将异常数据分为不符合用能业务特性的坏数据和缺失数据两类。针对坏数据问题，提出了基于改进K-Means聚类的异常数据识别方法，其中采用Davies-Bouldin（DB）指标解决聚类数K的选取问题；针对缺失数据问题，提出了基于误差反馈的异常数据组合式插补方法。为验证所提方法的有效性，从某园区5个用户4个月的用电数据中选取40组数据，前20组作为样本集以确定插补权重，后20组作为验证集进行验证与对比，结果表明，所提方法具有更高的稳定性与可靠性。     

Microwave dielectric properties of ultra-low loss Li2MgTi0.7(Mg1/3Nb2/3)0.3O4 ceramics sintered at low temperature by LiF addition

In this work, ultra-low loss Li₂MgTi_0.7(Mg_1/3Nb_2/3)_0.3O₄ ceramics were successfully prepared via the conventional solid-state method. X-ray photoelectron spectroscopy (XPS), thermally stimulated depolarization current (TSDC) and bond energy were used to determine the distinction between intrinsic and extrinsic dielectric loss in (Mg_1/3Nb_2/3)⁴⁺ ions substituted ceramics. The addition of (Mg_1/3Nb_2/3)⁴⁺ ions enhances the bond energy in unit cell without changing the crystal structure of Li₂MgTiO₄, which results in high Q·f value as an intrinsic factor. The extrinsic factors such as porosity and grain size influence the dielectric loss at lower sintering temperature, while the oxygen vacancies play dominant role when the ceramics densified at 1400?°C. The Li₂MgTi_0.7(Mg_1/3Nb_2/3)_0.3O₄ ceramics sintered at 1400?°C can achieve an excellent combination of microwave dielectric properties: ε_r =?16.19, Q·f?=?160,000?GHz and τ_f =??3.14?ppm/°C. In addition, a certain amount of LiF can effectively lower the sintering temperature of the matrix, and the Li₂MgTi_0.7(Mg_1/3Nb_2/3)_0.3O₄-3?wt% LiF ceramics sintered at 1100?°C possess balanced properties with ε_r?=?16.32, Q·f?=?145,384?GHz and τ_f =??16.33?ppm/°C.     

Induction plasma spheroidization of ZrB2-SiC powders for plasma-spray coating

To improve the microstructure and properties of ZrB₂-SiC (ZrB₂-30?vol%SiC, Z7S3) coatings, a facile synthesis route involving induction plasma spheroidization (IPS) has been proposed, and the morphologies, particle size distributions, and phase compositions of the feedstock powders were analysed by scanning electron microscopy and focused ion beam techniques. The obtained results showed that the surfaces of the produced powders contained eutectic-like and granular zones. Owing to the existence of a temperature gradient, the internal microstructure of the IPS-treated powder exhibited a three-layered structure consisting of a ′surface shell′, a ′transition layer′, and a ′porous core′. Additionally, the properties of the IPS-treated samples were compared with those of the spray-dried (SD) powders. The former exhibited good plastic deformation properties, and their single splats contained flattened structures, while the single splats of the SD powder melted only partially retaining some of their original characteristics.     

樟芝多糖通过降低NLRP3 Caspase1炎性小体表达改善帕金森小鼠神经行为学的机制研究

目的:研究樟芝多糖通过降低NLRP3-Caspase1炎性小体表达改善6-OHDA构建的帕金森小鼠模型的行为学机制。方法:利用6-OHDA脑内注射构建帕金森小鼠模型，通过酪氨酸羟化酶（TH）免疫组化染色和行为学判定小鼠模型的构建成功。利用樟芝多糖进行干预，分别在干预前、干预后的第1、3、7天4个时间点进行神经行为学实验，分别采用转棒实验、爬杆实验检测小鼠自主行为能力以及协调能力，4个时间点取小鼠尾静脉外周血采用ELISA法检测外周血中Caspase1和IL-1β的表达，樟芝多糖干预第7天时待进行完行为学实验后小鼠断颈处死，取小鼠脑组织-纹状体，Western blot法检测纹状体中Caspase1、proCaspase1、NLRP3的表达，高效液相色谱检测纹状体中单胺类神经递质的表达，RT-QPCR检测Caspase1、NLRP3、IL-1β、IL-4、IL-6的mRNA表达。NISSl染色检测小鼠脑组织神经细胞凋亡情况。 结果:6-OHDA脑内注射可以造成小鼠帕金森样病变，且TH蛋白表达显著下调，樟芝多糖干预后小鼠的行为学得到显著改善（P<0.05），纹状体中Caspase1、proCaspase1、NLRP3的表达显著下调，与模型小鼠相比具有统计学差异（P<0.05），且相关炎症因子Caspase1、NLRP3、IL-1β、IL-4、IL-6的mRNA表达下调（P<0.05），纹状体中单胺类神经递质表达上升（P<0.05）。结论:樟芝多糖可以通过下调NLRP3-Caspase1炎性小体表达来改善6-OHDA构建的帕金森小鼠模型行为改善，这可能是樟芝多糖治疗帕金森的机制之一。     

甲基氯硅烷精馏流程的模拟与优化

采用Aspen plus软件对工业七塔精馏过程进行全流程建模与模拟，优化工艺参数，研究了新的精馏节能工艺。对一甲塔等7个精馏塔采用双因素水平的灵敏度分析，考察了塔釜采出率、回流比、进料位置和塔顶压力对产品浓度和热负荷的影响，确定一甲塔最优的工艺参数：塔釜摩尔采出率为0.92，摩尔回流比为130，塔顶压力为0.18 MPa，总理论板数为400，在210块理论板位置进料。在此基础上，针对高能耗的脱高塔/脱低塔，模拟研究了双效精馏新工艺，新工艺可节省39.70%的年总成本；针对一甲塔模拟研究了热泵精馏新工艺，新工艺可降低41.42%的年总成本。     

Study on the Adaptability of Alkanolamide (LDEA) Lowering Oil/Water Interfacial Tension to Different Crude Oils

In order to investigate the high interfacial activity and fair oil phase adaptability of alkanolamide, “1:1” type lauric acid diethanolamide impurities (LDEA) were synthesized and purified by the column chromatography method to obtain dodecanoic acid diethanolamide (C₁₂DEA), ester mixture, etc. The exact structures of these compounds were further confirmed by IR, gas chromatogrph with mass spectroscopy (GC–MS), and NMR. The influence of each component on the interfacial tension of oil/water (IFT) was studied by systematic quantitative analysis. The results showed that (i) the strength of each system to reduce oil/water IFT is C₁₂DEA /DEA ≈ LDEA > C₁₂DEA/DEA/ESTER > C₁₂DEA/NaOH > C₁₂DEA > C₁₂DEA/ESTER > DEA. This indicates that LDEA contributes to the reduction of the oil/water IFT and the enhanced adaptability of crude oil in this order: DEA > > ESTER; (ii) when the IFT of the LDEA/DEA system reached an ultralow value, the minimum content of DEA in the system was 1%, and the maximum ester content was less than 5% when the LDEA/DEA/ESTER system reached the ultralow IFT; (iii) the possible mechanism of effect of LDEA components on the IFT and oil phase adaptability was proposed as the synergistic process among the hydrogen bonding, alkali effect, and interface self-assembly of molecules in the interfacial layer. The contribution of these three factors were hydrogen bonding > alkali effect > interface self-assembly.     

Hybrid self-inertia weight adaptive particle swarm optimisation with local search using C4.5 decision tree classifier for feature selection problems

ABSTRACT

Feature selection is an important task to improve the classifier’s accuracy and to decrease the problem size. A number of methodologies have been presented for feature selection problems using metaheuristic algorithms. In this paper, an improved self-adaptive inertia weight particle swarm optimisation with local search and combined with C4.5 classifiers for feature selection algorithm is proposed. In this proposed algorithm, the gradient base local search with its capacity of helping to explore the feature space and an improved self-adaptive inertia weight particle swarm optimisation with its ability to converge a best global solution in the search space. Experimental results have verified that the SIW-APSO-LS performed well compared with other state of art feature selection techniques on a suit of 16 standard data sets.