降胆固醇乳酸菌的筛选及其发酵条件研究

试验研究以市售的酸菜、香肠、酸奶、酱油、泡菜等为材料,用碳酸钙-MRS选择性培养基筛选出乳酸菌。将菌株接种到含胆固醇标准液的MRS液体培养基中,筛选出一株降胆固醇能力较强的乳酸菌。结合革兰氏染色、菌落的形态学、生理生化特征等鉴定其为干酪乳杆菌,命名为Lactobacillus casei L1。进一步采用单因素试验确定不同因素对胆固醇降解率的影响。最后采用正交试验确定:温度36℃、摇床振荡转数170 r/min、培养时间22 h条件下降解胆固醇效果最好,降解率可达43.6%。     

吡虫啉在土壤中的降解动力学研究

在实验室条件下，研究了吡虫啉在4种土壤中的降解动态。结果发现，吡虫啉在浙江土壤中降解最快T0.5为10．3d，在江西红壤中降解最慢T0.5为12．9d。土壤有机质含量和农药浓度对吡虫啉在土壤中降解有一定影响，土壤有机质含量越高降解越快，反之亦然。此外微生物对吡虫啉在土壤中的降解起了主要作用。     

润滑油用乙丙共聚物粘度指数改进剂的制备

针对润滑油用乙丙共聚物粘度指数改进剂的应用需求,设计一系列乙丙橡胶的热氧化降解体系,系统考察反应条件对乙丙橡胶热氧化降解的影响规律。采用乌氏粘度计、凝胶色谱仪和红外光谱分别对样品特性粘数、分子量及其分布和链段结构进行测定和表征,并分析探讨其热氧化降解机制。结果表明,引发剂A、B对乙丙橡胶降解均有促进作用,随着时间的延长降解程度增大;一定范围内引发剂浓度增加降解程度增大;降解体系胶油质量比1∶6的降解程度比1∶9大;金属铜离子能明显提高降解程度。采用0.3%~0.5%引发剂A和胶油质量比1∶6~1∶9的反应体系可制备出适当的分子量和较窄分子量分布的降解产物乙丙共聚物,经红外光谱分析其链段结构未出现异常变化。     

偏苯三酸酯基础油的摩擦降解及对抗氧化性能的影响

为研究润滑油在边界润滑条件下的摩擦降解及其对润滑油性能的影响,采用四球试验机考察偏苯三酸三异辛醇酯(TMTO)、偏苯三酸三异壬醇酯(TMTD)以及偏苯三酸三异十三醇酯(TMTT)在边界润滑条件下的摩擦学性能。结果表明:分子结构对偏苯三酸酯在边界润滑条件下的润滑性能有较大影响,链长最长的TMTT的减摩与抗磨性能优于TMTO与TMTD。利用高压差示扫描量热仪(PDSC)及热重分析仪(TGA)研究四球试验前后3种基础油的抗氧化性能及热分解性,并测试摩擦试验前后润滑油的黏度与酸值变化。结果表明:边界润滑条件下的摩擦过程会导致偏苯三酸酯类基础油黏度升高、酸值降低、氧化安定性下降;润滑性能良好的基础油在一定程度上阻止或减缓润滑油本身氧化反应的发生;在边界润滑条件下,偏苯三酸酯一部分在机械剪切及水解作用下分解会生成小分子的化合物,另一部分在氧化作用下聚合生成大分子化合物。     

水培油麦菜对吡虫啉的降解研究

吡虫啉是一种低毒新型烟碱类杀虫剂,具有触杀、渗透、胃毒和内吸等多种杀虫方式,与其他杀虫剂没有交互抗性。本实验利用水培油麦菜降解吡虫啉,并对降解规律进行了研究,吡虫啉含量用高效液相色谱法检测。实验结果表明:(1)在水培蔬菜生长的嫩芽期,吡虫啉能够被降解,但是降解非常缓慢;(2)在水培油麦菜的生长期和衰老期,吡虫啉的降解快速下降最后趋于平缓;(3)水培蔬菜生长的不同时期对吡虫啉降解的能力不同,水培油麦菜在生长期和衰老期对营养液中吡虫啉的降解能力要强于嫩芽期。     

大气中苯系物的气相色谱测定

<正> 本法采用活性炭管采集空气中苯、甲苯、二甲苯、苯乙烯、用二硫化碳解吸进样。柱子选用3.5%有机皂土34和2.5％邻苯甲酸二壬酯作固定液,用氢焰离子化检测器检测。以保留时间定性,峰高定量。 本法对苯、甲苯、二甲苯、苯乙烯的检测限分别为0.8×10~(-6)、1.6×10~(-6)、3.2×10~(-6)、1.6×10~(-6)μg。     

臭氧降解水中农药的试验研究

目的 评价臭氧对水中农药的降解率，并对降解副产物进行定性分析。方法将臭氧通入水中20min，检测臭氧对水中农药的降解率及副产物。结果通臭氧20min的去离子水中，臭氧的浓度为0．24mg／L；敌敌畏、乐果、对硫磷和甲胺磷降解率分别为97．6％、45．2％、40．2％和34．3％。乐果副产物氧乐果，对硫磷的副产物：0，0-二乙基0-（4-硝基苯基）磷酸酯。结论臭氧可以降解水中的4种有机磷农药．但会产生毒性更高的降解产物。     

合成润滑油多因素降解实验方法研究

以蓖麻油基润滑油为例,研究润滑油在非单一因素作用下的降解实验方法。在润滑油生物降解因素基础上增加非生物降解因素———光照,来模拟润滑油在自然环境中的真实降解情况,建立非单一降解因素联合作用下润滑油的室内降解实验方法,运用红外光谱法检测润滑油降解后残余含量,确定润滑油降解率。结果表明：新方案得到的实验数据具有较好的稳定性和重复性,且与文献结果具有较好的一致性;新实验方案可以得到润滑油的光降解率,虽然光降解率相对较低,但光对润滑油的降解作用不能忽略。     

耐甲氧西林金葡菌检测方法比较

目的:研究比较不同方法检测(MRSA)的效果。方法 :将从临床感染标本分离获得的148株金葡菌菌株分别采用头孢西丁、苯唑西林纸片扩散法、基因聚合酶链反应(PCR)法检测MRSA菌株,以采用基因聚合酶链反应(PCR)法作为判断MRSA的"金"标准。并用琼脂稀释法测定148株葡萄球菌对青霉素、红霉素等10多种抗菌药物的药物敏感性。结果 :头孢西丁纸片法对MRSA的检测灵敏度为93.18%,特异度为95%,漏诊率为6.82%,误诊率为5%,Youden指数为0.818;苯唑西林纸片法对MRSA的检测灵敏度为81.82%,特异度为76.67%,漏诊率为18.18%,误诊率为23.33%,Youden指数为0.585,说明苯唑西林纸片法对MRSA的检测准确性低于头孢西丁纸片法。结论:PCR技术检测MRSA快速且敏感性和特异性强,可作为首选鉴别方法。头孢西丁纸片扩散法使用方法简单,对实验条件无特殊要求,较苯唑西林纸片扩散法结果更准确。     

和谐机车齿轮油极压抗磨添加剂降解规律的研究

利用Falex四球试验机评价硫、磷添加剂的降解对齿轮油的极压抗磨性能的影响;利用傅里叶变换红外光谱仪确立硫、磷添加剂中起主要作用官能团的吸收峰位;研究某和谐机车齿轮油在行车过程中极压抗磨添加剂的降解规律。结果表明：试验过程中,油品的极压性能下降,抗磨性能变好;极压抗磨添加剂的降解主要发生在10万km范围内,主要降解的是含P=S基团的磷系添加剂,试验结束时其降解率达到17%;20万km范围内,试验的齿轮油能满足和谐机车对其极压抗磨性能的要求。     

Investigation of long-term engine oil performance using lab-based artificial ageing illustrated by the impact of ethanol as fuel component

The effect of ethanol and its combustion products on the lubrication system is not very well understood. In this paper, a novel lab-based artificial ageing method for the evaluation of engine oils for bio-fuelled automotives and the results thereof are presented. Artificial ageing of three fully formulated engine oils with addition of ethanol, acetaldehyde, and acetic acid was carried out. The oil formulations chosen represent a consequent series of optimisation steps based on the engine oil performance in terms of preservation of typical oil parameters, e.g. base reserve and oxidation, observed during the artificial ageing procedure. It was shown that ethanol as well as acetaldehyde has almost no effect on the oil degradation especially in the case that advanced additive technology was used. On the contrary, acetic acid significantly affected the formulated oil showing influence on the detergent chemistry and even caused sludge formation. The use of the novel artificial ageing method proved to clearly differentiate the impact of the respective compounds added with the possibility to simulate enhanced stress conditions without the need of time-consuming and expensive engine bench tests. Hence, the novel setup offers valuable input for the formulation and the pre-selection of future engine oils suitable for bio-fuel.     

轴承冲洗机设计

为满足轴承冲洗机油液的清洁度要求,全新设计制造一种轴承冲洗机.轴承冲洗机采用供油箱和回油箱的双油箱结构,供、回油箱分别连接供油泵和回油泵,供油管路和回油管路上设置油滤,供油泵打出的油液经过油滤进入轴承,油液从轴承油孔喷出后流回油箱,回油箱中的油液过滤干净后,提供给供油箱,通过这种双过滤循环系统可保证冲洗油液的清洁度要求.供、回油箱隔板上部位置开有连通孔,使两油箱液面动态平衡,消除供、回油流量的不匹配.轴承冲洗机能够达到油液的清洁度要求,使冲洗完的航空发动机轴承内无杂质,保证轴承的使用性能和寿命.     

Behavioral differences between group I and group II base oils during thermo-oxidative degradation

A simple approach has been adopted to accelerate thermo-oxidative degradation of selected group I and group II base oils by heating each oil in air at specified temperatures. Chromatographic, spectroscopic and thermal techniques are then applied to establish fundamental differences between the oil types by monitoring compositional changes due to their degradation. The oil properties investigated include hydrocarbon type composition, boiling range distribution, the amount of oxygen and types of oxygenated species, molecular weight distribution, and low-temperature fluidity. While most troublesome degradation products from group I oil are insoluble deposits, group II oil yields oil-soluble low as well as high boiling oxygenated species. It is found that the group I oil degradation path reflects preferential reaction of aromatic hydrocarbons to yield polar compounds and insoluble residue. In contrast, the degradation of the group II oil yields high amounts of oxygenated products at the expense of saturates. Since additives are often utilized to protect the base oil from degradation, the above findings are discussed in the context of selection of proper additives for the formulation of engine oil or other lubricants using different oil types.     

基于PSO-ELM的液压油性能衰退预测及分析

提出基于粒子群优化（Particle Swarm Optimization,PSO）的极限学习机（Extreme Learning Machine,ELM）的液压油性能衰退预测方法。以L-HM46抗磨液压油为研究对象,设计液压油性能衰退实验,检测油液的黏度、张角、水分含量、衰退度。基于提出的液压油性能衰退预测方法,利用遍历搜索和PSO算法分别对ELM的外部、内部参数进行优化选取,从而建立最优的性能衰退预测模型。将油液的黏度、张角、水分含量作为模型输入特征向量,衰退度作为模型输出,采用PSO-ELM性能衰退预测模型对液压油性能进行仿真分析。结果表明：PSO-ELM算法计算结果与实验数据吻合较好;PSO-ELM算法预测精度达到了98.47%,高于ELM算法的预测精度,表明PSO-ELM算法能更准确地预测液压油的衰退情况,为确定换油时机提供参考。     

菜籽油基生态淬火油的研制

传统的矿物油基淬火油由于很难进行生物降解,对环境造成严重污染。调查表明矿物油是地下水源的最大污染源,各国对有关矿物油的使用和排放都已提出了越来越严格的要求。因此研制新型的环保型淬火油势在必行。论述一种基于菜籽油的植物油基淬火油,它不仅具有突出的环保和生态优势而且具有优良的冷却性能,是很有希望替代矿物油的新型生态淬火油,有着广阔的应用前景。     

Influence of degradation on the film‐forming properties of polyolester oils

The film thicknesses of two polyolester degraded oils were measured over a wide range of temperatures to investigate the influence of degradation on film‐forming properties. The results have been interpreted in the light of the idea that degradation of an ester lubricant can produce two different types of product which have opposing influences on film‐forming properties. One is the formation of smaller, polar molecules, such as acids, which may result in a decrease in effective pressure—viscosity coefficient. The other is the formation of larger, bulky molecules such as sludge, which result in increased pressure—viscosity coefficient. The effective pressure—viscosity coefficient decrease with degradation of the oil thus is made up of an earlier stage involving a series of reactions, followed in a later stage by an increase.     

On the use of intrinsic fluorescence emission ratio in the characterization of hydraulic oil degradation

Intrinsic fluorescence emission of oil was used to develop a technique and detector for evaluating oil degradation. Test results for hydraulic oils with and without zinc dialkyldithiophosphates additives and calcium-based dispersant were in conformance with the results of optical emission spectrometry, particulate counts, optical microscopy, total acid number, and viscosity tests. The ratio of intrinsic fluorescence emission was found to be a parameter independent of the concentration of dust and iron contaminants in non-additive oil. It proved to be dependent on oil chemical degradation, becoming a tool to detect degradation before incipient wear at the tribological interface becomes relevant. The study showed that intrinsic fluorescence emission ratio gives sufficient information to characterize and evaluate oil degradation.     

A method for the identification and quantitation of hydraulic fluid contamination of turbine engine oils by gas chromatography–chemical ionisation mass spectrometry

The identification of aircraft hydraulic fluid contamination of turbine engine oils is difficult. Repeated field incidents of this type of cross contamination have led to the requirement to develop a method suitable for quantitation of such contamination. A gas chromatography–chemical ionisation mass spectrometry method for the determination of H‐537 hydraulic fluid contamination in turbine engine oil was developed and validated. The intraday and interday relative standard deviations of the standards were 3–7% and 5–9%, respectively. Mean recoveries of hydraulic fluid in turbine engine oil were 90–94%, and the calibration curve was linear with R² = 0.999. Limits of detection and quantitation were 0.05% (w/w) and 0.5% (w/w), respectively. The method was successfully applied to laboratory degraded samples and field samples. Copyright © 2012 John Wiley & Sons, Ltd.     

Effects of sunflower oil added to base oil on the friction coefficient of statically loaded journal bearings

In this study, sunflower oil at different concentrations of between 1 and 50% was added to base oil to obtain lubricating oil candidates. The lubricating oil candidates were characterised by ASTM methods, and their effects on the friction coefficient at 25 and 100°C at different speeds and loads in a statically loaded journal bearing were determined. The technological characteristics of the sunflower oil were determined according to standard methods. The study shows clear evidence that the modification of friction by sunflower oil is at least equivalent to that by mineral oil, and the lubricationg oil candidates containing sunflower oil show a reduction in the coefficient of friction.     

蒸发式冷凝器的设计选型及在氨制冷系统中的应用

介绍了用温降计算法进行蒸发式冷凝器的选型计算,分析了影响蒸发式冷凝器传热效率的因素,指出设置洗涤式油分离器对于氨制冷系统的有利作用。同时结合工程实例对蒸发式冷凝器的管路进行了设计,并对其结构提出了改进意见。