A Fast Extraction Method in the Applicaton of UHV Transmission Line Fault Location

To aim at the distribution parameter characteristics of UHV transmission line, this paper presents a fast extraction method (FE) to extract the accurate fundamentals of current and voltage from the UHV transmission line transient process, and locates the fault by utilizing two-end unsynchronized algorithm. The simulation result shows that this method has good performance of accuracy and stability, and has better location precision by comparing with results of one cycle Fourier algorithm. Therefore the method can efficiently improve the precision of fault location during the transient process, and makes the error of location results less than 0.5%.

Application of the Electrochemical Method for Stripping Eu^（3＋） after Extraction with Benzo－15－crown－5 in Dichloromethane

Eu3+ is extracted at pH 6 with 5. 0×10-2 mol/L benzo-15-crown-5 in dichloromethane from 5. 0×10-2 mol/L aqueous solution of lithium picrate. The enriched extractability has been investigated. In a concentration range from 2. 4 ×10-4 to 1. 8 ×10-3 mol/L solution of europium nitrates, the enrichment coefficients are calculated with the phasc ratio (organic/aqueous) of 1: 5 or 4: 25. The ability of 0. 5 mol/L HNO3 as a back-extractant is discussed with the volume ratio [organic/(0. 5 mol/L HNO3)] of 1 : 3. Crown ether and picric acid exist in the back-extractivephase. Eu3+ is effectively separated from the organic phase by the electrochemical method. The separation efficiency is more than 84%. The optimum electrolysis time or cell voltage is obtained from the relation between the electrolysis current and the time or the voltage.

Analysis of Influence Factors for FCC Slurry Separation by Mixed Solvent Extraction

Daqing FCC slurry was treated using mixed solvent containing N,N-dimethylformamide(extraction solvent)and n-paraffin(stripping-agent).The influence of solvent formulation(ratio of DMF/stripping-agent),temperature,time and solvent-oil ratio on yield and aromatics content of the extract oil were analyzed by a four-factor and three-level orthogonal experimental design.The polynomial regression models between the extract oil yield and aromatics content with the four factors were established.Response surface analysis showed that solvent formulation,temperature and solvent-oil ratio have significant effects on extraction result and there is an interaction between temperature and solvent-oil ratio on aromatics content,when the FCC slurry is extracted by mixed solvent.However,the extraction time has no significant effect.The optimal conditions for FCC slurry extraction covered:a solvent mixed ratio of 2.3,a temperature of 62.8℃,a solvent-oil ratio of 3.2,and a time of 35 min.The result of verification experiment was in good agreement with the prediction of the model.

基于UPLC-QTOF/MS的小麦发芽代谢组学分析方法

为探究不同提取方法对发芽小麦代谢物提取效果的影响,本研究建立了基于超高效液相色谱-四级杆飞行时间质谱(UPLC-QTOF/MS)的发芽小麦非靶向代谢组学样品前处理方法和分析方法,以发芽2 d周麦26籽粒为材料,设计提取溶剂、提取方式、提取时间3个因素在3个水平上L9(34)正交试验,并通过主成分分析和聚类分析确定提取效果最佳的组合。以80%乙腈(0.1%甲酸)震摇提取30 min可检测出1609个代谢峰,说明提取溶剂对代谢物提取效果起主要作用。共鉴定出92种小麦代谢物。

A New Diagnostic Method Applied to Gearbox Missing Gear Faults——LOD-ICA

With the increasingly stringent requirements for carbon emissions,countries have increased the scale of clean energy use in recent years.As an important new clean energy source,the ratio of wind power in energy utilization has been increasing.The horizontal axis wind turbine is the main form of wind power generation,which is subject to random wind loads during operation and is prone to various failures after a long period of operation,resulting in reduced power generation efficiency or even shutdown.In order to ensure stable external power transmission,it is necessary to perform fault diagnosis for wind turbines.However,the traditional time-frequency analysis method is defective.This paper proposes a new LOD-ICA method to realize the resolution of the vibration signals mode mixing problem incorporated the merits of both methods.The LOD-ICA method and the LOD method based on noise-assisted analysis decompose the same signal to produce different signal components.The feasibility of the LOD-ICA method was verified by comparing the correlation coefficients between each of the signal components generated by the two methods and the original signal.In the field of wind turbine fault diagnosis,the LOD-ICA method is employed to the fault characteristics of gearboxes to extract the fault signs of vibration signals,further demonstrated the superiority of the LOD-ICA method in processing vibration signals of rotating machinery.

金银花总黄酮低共熔溶剂提取工艺优化

目的优化金银花总黄酮低共熔溶剂提取工艺。方法在单因素试验基础上,以1,3-丁二醇与氯化胆碱比例、液料比、超声时间为影响因素,总黄酮得率为评价指标,响应面法和BP神经网络优化提取工艺。结果BP神经网络优化总黄酮得率高于响应面法优化。最优条件为1,3-丁二醇与氯化胆碱比例2.7∶1,液料比27∶1,超声时间29 min,总黄酮得率为7.85%。结论该方法稳定可靠,可用于低共熔溶剂提取金银花总黄酮。

皮革和毛皮中喹啉类化合物的测定

通过参考国内相关检测标准方法,采用气相色谱-质谱法对不同皮革种类中喹啉类化合物进行了分析。通过对提取方式、提取溶剂、水浴温度、超声时间等条件的优化,建立了皮革和毛皮中喹啉类化合物的检测方法。实验结果表明,喹啉类化合物标准曲线线性范围为0.5~50.0 mg/L时,各化合物的线性相关系数都在0.996以上。最优的前处理条件是使用甲醇溶剂,在70℃的水浴温度下超声提取60 min。

超声辅助低共熔溶剂法提取太白贝母总黄酮及其抗氧化活性研究

采用超声辅助低共熔溶剂法提取太白贝母总黄酮,以太白贝母总黄酮提取率为考察指标,通过单因素实验和响应面法对提取工艺进行了优化,并通过DPPH自由基清除实验和ABTS自由基清除实验研究了其抗氧化活性。结果表明,在超声功率为69 W、料液比为1∶18(g∶mL)、超声温度为79℃、超声时间为27 min的最优工艺条件下,太白贝母总黄酮提取率可以达到17.7004%,与预测值相差极小;太白贝母总黄酮是一种强抗氧化剂,对DPPH自由基、ABTS自由基具有较强的清除能力,在浓度为16 mg·mL^(-1)时,清除率分别达到82.15%、90.42%,与VC无明显差异。超声辅助低共熔溶剂法操作简便、提取率高,适用于太白贝母总黄酮的提取。该研究为太白贝母药材资源的开发利用提供了参考。

天然产物提取技术的实验设计与优化

针对我校应用化学专业实验部分教学内容单一性较强,授课过程学生参与的主动性较差,不能有效践行以学生为本的教育理念,开发了从西红柿、菠菜、橙皮、红辣椒等天然产物中提取有用成分的综合设计性实验技术。学生可以自由选择天然产物,组成2~3人团队,通过文献查阅、实验方案设计、有用成分的提取与分离、产品检测、数据分析等教学环节,培养学生运用应用化学专业的理论知识来解决生活实际问题的能力。将生活实际转化为综合性设计性实验内容,强化专业实验技能培养,增强应化专业学生实践能力,从而满足工程教育专业认证背景下对于人才培养的要求。

黄连生物碱超声辅助低共熔溶剂提取工艺优化

目的优化黄连生物碱超声辅助低共熔溶剂提取工艺。方法以葡萄糖-乳酸(1∶5)为低共熔溶剂。在单因素试验基础上,以提取时间、含水量、液料比为影响因素,生物碱得率为评价指标,Box-Behnken响应面法优化提取工艺。结果最佳条件为提取时间35 min,含水量26%,液料比33∶1,生物碱得率为7.22%。结论该方法稳定可靠,切实可行,可为黄连开发利用提供参考。

赤泥中稀土提取与分离技术研究进展

稀土元素被誉为“工业维生素”,具有优异的磁、光、电性能。随着新能源汽车等新兴行业对稀土需求量的不断增加,稀土资源日益紧缺,从二次资源中回收稀土已成大势所趋。作为一种重要的二次资源,赤泥的产量高、堆存量大、稀土含量较高。本文介绍了赤泥中稀土元素的赋存状态,概述了从赤泥中提取分离稀土元素的湿法浸出工艺和火法-湿法联合工艺;介绍了溶剂萃取法和离子交换法两种分离工艺的研究现状,对比分析了不同处理工艺的优缺点,并通过比较不同工艺的优劣,指出降低回收成本、提高环境效益是未来赤泥资源化利用研究的重要方向。

昏暗环境下自适应ORB-SLAM2算法研究

本文针对ORB-SLAM2算法在黑暗环境或纹理较少的环境下提取特征点少,从而导致SLAM系统定位精度不高、匹配对数较少,进而导致系统崩溃的问题,提出了一种基于自适应阈值的特征点提取算法与改进的四叉树均匀化策略。首先基于图像的亮度进行基于自适应阈值的FAST特征点提取,之后通过改进的四叉树均匀化策略对图像的特征点进行剔除与补偿,完成特征点选取。实验结果表明,与原算法相比,改进后的特征点提取算法在黑暗环境与纹理较少的环境下,匹配对的数量提升了17.6%,SLAM轨迹精度提升了49.8%,有效的提升了SLAM系统的鲁棒性和精度。

IPE-23萃取剂在含锂废液中回收锂的应用

从废旧锂电池回收废液中进一步提取锂资源兼具经济和环境效益,β-双酮类溶剂萃取体系因其良好的萃锂性能得到了广泛的关注,但目前β-双酮类萃取剂的种类较少导致在选择上有一定的局限性。本研究通过Gaussian 16、Multiwfn软件进行了萃取剂分子表面静电势和萃锂反应吉布斯自由能变的理论计算,结果表明—NO_(2)、—CF_(3)、—CN取代基通过改变β-二酮分子范德华表面的静电势极值来提升萃锂性能,在此理论基础上开发出β-二酮类选择性提锂萃取剂IPE-23;以锂萃取率、分离比、萃取分相、萃取剂在水相中的溶损(以水相中的化学需氧量COD计)等衡量指标,研究了萃取剂浓度、温度、相比、加碱量等因素的影响,经过三级逆流萃取-三级逆流洗涤-CO_(2)酸化反萃工艺处理,锂的萃取率达到97%,分配比D_(Li)=21.90,锂钠分离系数为423.85,萃余液pH为11.3,COD为675.2mg/L,反萃液中锂浓度达到6.66g/L。本研究有望为废旧锂电回收废液中锂资源的高效循环回用提供技术参考与理论支撑。

包覆低共熔溶剂的聚苯乙烯微胶囊吸附Li^(+)的性能研究

为实现绿色、低成本从海水中提锂的目标,采用同轴共流微流体技术结合溶剂挥发法制备包覆有低共熔溶剂(甲基三辛基氯化铵/癸酸)的聚苯乙烯微胶囊。所制备的微胶囊颗粒呈均一的球形。将该微胶囊用作萃取Li^(+)吸附剂,系统研究了吸附时间、吸附温度、溶液pH、初始锂浓度和固液比对Li^(+)吸附量和萃取率的影响。结果表明在吸附Li^(+)水溶液时,微胶囊对Li^(+)的最大吸附量为32 mg·g^(-1)。碱性条件时微胶囊对模拟海水中的Li^(+)吸附分配比为10.22 L·g^(-1)。

锂云母酸浸液萃取除杂

锂云母酸法浸出液含有大量杂质金属,使用传统化学沉淀法会引起大量产物损失。为了降低浸出液除杂过程中的产物损失,使用溶剂萃取法进行萃取除杂工艺研究。通过对不同萃取剂组合萃取除杂效果的研究,确定使用P204作为萃取剂。考察了萃取过程中不同因素的影响,并使用H_(2)O_(2)预氧化水相里的Fe^(2+),强化萃取效果。结果表明:在有机相组成为30%P204+70%磺化煤油、料液初始pH为2.4、相比O/A=1、萃取时间10min和振荡频率300 r/min的单级萃取最佳条件下,铁除杂率为99.89%、铝除杂率为31.23%、锂和铷的萃取率分别为7.63%和14.85%。相比于化学沉淀法,锂和铷的回收率得到了30%左右的提高。

超声辅助低共熔溶剂提取车前草总黄酮的工艺研究

为探究车前草总黄酮的最佳提取工艺,以总黄酮提取率为评价指标,在提取温度、反应时间、低共熔溶剂含水量、摩尔比等单因素试验基础上进行响应面优化。结果表明,车前草总黄酮的最佳提取工艺为提取温度34℃,反应时间41 min,低共熔溶剂含水量47%,摩尔比2.2:1。在此条件下,总黄酮的提取率可达6.28%。研究为车前草的开发及综合利用提供理论支撑。

纤维基离子液多酸催化剂的合成及其超深快速脱硫性能研究

采用浸渍法将Keggin型P-Mo-W多金属氧酸盐(POM)与双离子液体结合在醋酸纤维素(CA)上,获得一种用于萃取氧化脱硫(EODS)的成型催化材料,采用响应面设计实验,探究温度、催化剂质量、氧硫比以及多酸负载量对脱硫的影响。研究表明,最佳脱硫反应条件为:模拟柴油25 mL,催化剂0.16 g,温度63℃,氧硫比4.8,多酸负载量1.08,反应2 h,可将模拟燃油中99.2%的DBT脱除。

低共熔溶剂提取晋产吸水石栽培铁皮石斛多糖工艺优化及抗氧化活性研究

铁皮石斛为我国传统的药用和食用同源的植物,具有极高的中药价值,尤其是其多糖含量最为显著。本研究以山西产吸水石栽培的铁皮石斛为原材料,通过单因素及响应面分析法优化低共熔溶剂提取铁皮石斛多糖工艺,然后分析不同浓度多糖对DPPH自由基、羟基自由基和ABTS+自由基的清除效果。结果显示,低共熔溶剂提取铁皮石斛多糖工艺:采用L-脯氨酸-草酸低共熔溶剂体系,在料液比1∶21(g/mL)、温度56℃的条件下超声30 min,最终多糖得率为(34.35±0.2)%。进行抗氧化实验分析,发现5 mg/mL的多糖浓度对DPPH自由基、羟基自由基和ABTS自由基的清除率最高,达到37.7%、96.6%和77.8%。本研究为铁皮石斛多糖的提取提供了一种有效的方法,同时探究了多糖添加量对抗氧化能力的变化,为铁皮石斛多糖的提取和抗氧化添加剂的开发提供思路。

Determination of a suitable index for a solvent via two-column extractive distillation using a heuristic method

The traditional approach to solvent selction in the extractive distillation process strictly focuses on the change in the relative voltility of light-heavy components induced by the solvent.However,the total annual cost of the process may not be minimal when the solvent induces the largest change in relative volatility.This work presents a heuristic method for selecting the optimal solvent to minimize the total annual cost.The functional relationship between the relative volatility and the total annual cost is established,where the main factors,such as the relative volatility of the light-heavy components and the relative volatility of the heavy-component solvent,are taken into account.Binary azeotropic mixtures of methanol-toluene and methanol-acetone are separated to verify the feasibility of the model.The results show that using the solvent with the minimal two-column extractive distillation index,the process achieves a minimal total annual cost.The method is conducive for sustainable advancements in chemistry and engineering because a suitable solvent can be selected without simulation verification.

稀土元素萃取分离技术研究现状与展望

石油炼制与化工催化剂是稀土应用的一个重要领域。随着对稀土需求量的不断上升,获得大量纯净的稀土元素成为挑战。通过梳理沉淀法、离子交换法、溶剂萃取法、膜分离法、吸附法和电化学法等稀土元素分离技术,从萃取分离技术的高效性、选择性、经济性和环保可持续性等方面对稀土萃取分离技术的发展进行总结,并评价各种工艺技术的优缺点,最后展望稀土萃取分离技术的发展前景。