改良柱前荧光胺衍生化-高效液相色谱法测定猪肉中11种磺胺类药物残留

建立改良的磺胺类药物与荧光胺反应的衍生化方法,并应用于猪肉中11种磺胺类药物的高效液相色谱-荧光法测定.选用0.1 mol/L KH2PO4溶液(pH 3.0)0.8 mL、0.3 mg/mL荧光胺溶液0.2 mL与磺胺类药物发生衍生化反应,4℃避光反应40 min,得到磺胺-荧光胺衍生产物.该衍生化方法稳定、可靠,衍...     

大豆异黄酮药性作用的研究进展

关于大豆异黄酮的药性作用及其机理的研究主要涉及3个方面:(1)骨质方面,大豆异黄酮可以防止更年期妇女的骨丢失和骨质疏松,这可能与骨质保护素的mRNA表达水平有关.(2)血管和肠道方面,大豆异黄酮可以防止动脉硬化,降低血脂和胆固醇,改善肠道内菌群构成.(3)肿瘤和肾脏等细胞方面,大豆异黄酮对多种肿瘤细胞有抑制和治疗作用,对肾脏等细胞具有保护作用.未来将会把更多的动物实验结果用于人类的临床研究,在分子水平上进一步揭示大豆异黄酮的药性作用机理,开发出新的药物和保健品.     

利用镀件前处理酸洗废液制取超顺磁性纳米颗粒

本文主要论述了酸洗废液的由来,以及将其作为有用资源,利用新型的超声辅助化学共沉法来制取超顺磁性纳米颗粒,该工艺运行稳定,操作简单,治理废水的同时能获得高附加值的产品。     

跨域联合学习与共享子空间度量的车辆重识别

目的 现有的跨域重识别任务普遍存在源域与目标域之间的域偏差大和聚类质量差的问题,同时跨域模型过度关注在目标域上的泛化能力将导致对源域知识的永久性遗忘。为了克服以上挑战,提出了一个基于跨域联合学习与共享子空间度量的车辆重识别方法。方法 在跨域联合学习中设计了一种交叉置信软聚类来建立源域与目标域之间的域间相关性,并利用软聚类结果产生的监督信息来保留旧知识与泛化新知识。提出了一种显著性感知注意力机制来获取车辆的显著性特征,将原始特征与显著性特征映射到一个共享子空间中并通过它们各自全局与局部之间的杰卡德距离来获取共享度量因子,根据共享度量因子来平滑全局与局部的伪标签,进而促使模型能够学习到更具鉴别力的特征。结果 在3个公共车辆重识别数据集VeRi-776（vehicle re-identification-776 dataset）、VehicleID（largescale vehicle re-identification dataset）和VeRi-Wild（vehicle re-identification dataset in the wild）上与较新方法进行实验对比,以首位命中率（rank-1 accuracy,Rank-1）和平均精度均值（mean average precision,mAP）作为性能评价指标,本文方法在VeRi-776→VeRi-Wild,VeRi-Wild→VeRi-776,VeRi-776→VehicleID,VehicleID→VeRi-776的跨域任务中,分别在目标域中取得了42.40%,41.70%,56.40%,61.90%的Rank-1准确率以及22.50%,23.10%,41.50%,49.10%的mAP准确率。在积累源域的旧知识表现中分别取得了84.60%,84.00%,77.10%,67.00%的Rank-1准确率以及55.80%,44.80%,46.50%,30.70%的mAP准确率。结论 相较于无监督域自适应和无监督混合域方法,本文方法能够在积累跨域知识的同时有效缓解域偏差大的问题,进而提升车辆重识别的性能。     

热成像技术在乙烯裂解炉热故障诊断中的应用

概述了红外热成像技术应用于石化设备检测的基本原理和方法,着重阐明了在乙烯装置裂解炉热故障识别与诊断方面的应用,分析了故障成因。     

火电厂实现废水零排放途径的探讨

我国水资源严重短缺且环境质量仍较差,火电厂作为工业用水和废水排放大户必须提高水资源的利用率并减少废水排放。该文阐述了废水零排放的重要性和现状,对废水零排放实现的途径进行探讨,就其存在的问题进行了思考。     

汽油和液化石油气双燃料供给系统的开发

本文从液化石油气 (LPG)的理化特性和燃烧特点出发 ,阐述了LPG作为发动机燃料的优缺点。介绍了HH4 6 5Q汽油机双燃料 (汽油和LPG)供给系统 ,通过对两者排放性能和动力性能分析 ,展示了液化石油气的应用前景     

Effects of buffer gas composition on low temperature ignition of iso-octane and n-heptane

Experimental and numerical studies have been performed on the thermal and chemical effects of buffer gas composition on low temperature ignition of iso-octane and n-heptane. Experiments were conducted using a recently developed rapid compression machine in the temperature range of 600–850 K. Three buffer gases were studied including nitrogen (N₂), argon (Ar), and a mixture of Ar and carbon dioxide (CO₂) at a mole ratio of 65.1%/34.9%. Iso-octane was studied at 20 bar, ? = 1, and a dilution level of buffer gas to O₂ of 3.76:1 (mole ratio). n-Heptane was studied at 9 bar, ? = 1, and a dilution level of buffer gas to O₂ of 5.63:1 (mole ratio). For experiments where two-stage ignition was observed, the buffer gas composition had no impact on the first-stage ignition time but, as expected, it caused differences in the total heat release, pressure and temperature rise after the first-stage ignition. As a consequence, significant differences were observed for the total ignition delay time as a function of the buffer gas composition, with up to 40% and 42.5% faster total ignition time for iso-octane and n-heptane, respectively, by using Ar instead of N₂. The chemical effects of the buffer gas composition were studied experimentally by comparing the results of the N₂ and Ar/CO₂ (65.1%/34.9%) mixtures, recognizing that while the Ar/CO₂ mixture has the same heat capacity as N₂, its predicted combined third-body collision efficiency is about 76% higher than N₂. The experimental results showed negligible chemical effects on the first-stage and total ignition delay times. Numerical simulations were carried out over a wider range of temperatures for pure N₂, Ar, and CO₂ as buffer gases. Results showed that thermal effects are very pronounced and dominated at the negative temperature coefficient and two-stage ignition conditions, which is consistent with the experimental results and previous studies in the literature. However, the simulation results also showed at temperatures higher than 850 K, the chemical effects of CO₂ became more important than the thermal effects.     

"双一流"建设背景下双语研究生课程建设的研究与探讨

文章结合食品科学专业研究生的教学与实践,分析双语教学在研究生教学过程中的重要性,以及学校在双语教学存在的问题和现状,对"双一流"建设背景下双语研究生课程建设相应的改革措施进行了探讨。     

化学沉淀法制备磷酸铁锂正极材料的研究进展

磷酸铁锂(LiFePO4)是一种非常有应用前景的锂离子电池正极材料,化学沉淀法是制备这种材料的理想方法。本文从不同的前驱体合成路线角度出发,针对金属离子掺杂和表面碳包覆这两种改性手段,对化学沉淀法制备LiFePO4正极材料国内外的研究进行综述,对当前研究过程中存在的问题和未来的研究方向进行了评论和展望,为LiFePO4正极材料的研究提供了参考。