冷轧连退线张力控制模型优化策略

针对某钢厂冷轧连退机组生产钢卷规格变化时张力波动问题,提出了张力数学模型及优化算法,将前后带钢张力波动降到最低,保证了生产连续稳定进行。     

Enzymatic Synthesis of l‐Ascorbyl Fatty Acid Esters Under Ultrasonic Irradiation and Comparison of Their Antioxidant Activity and Stability

A series of novel l ‐ascorbyl fatty acid esters were synthesized by catalization of <i>Novozym<sup>®</sup> 435</i> under ultrasonic irradiation and characterized by infrared spectroscopy, electrospray ionization mass spectra, and nuclear magnetic resonance. Their properties especially antioxidant activity and stability were investigated. The results showed that the reducing power, the scavenging activity of hydroxyl radical and 2,2‐diphenyl‐1‐picrylhydrazyl radical were decreased with the increase of the number of carbon atoms in fatty acid. The hydroxyl radical scavenging activity and reducing power of l ‐ascorbyl saturated fatty acid esters were better than that of tert‐butylhydroquinone. The induction period in lipid oxidation of l ‐ascorbyl saturated fatty acid esters and tert‐butylhydroquinone were longer than that of l ‐ascorbyl unsaturated fatty acid esters and l ‐ascorbic acid both in soybean oil and lard. Besides, the l ‐ascorbyl fatty acid esters showed different stabilities in different conditions by comparing with l ‐ascorbic acid, and the l ‐ascorbyl saturated fatty acid esters were more stable than l ‐ascorbyl unsaturated fatty acid esters in ethanol solution.     

Rapid lactate oxidase‐based assay for lactate content in milk to ascertain its hygienic quality

A rapid method for qualitative and quantitative assaying of l ‐lactate in milk is described. The method is based on oxidation of lactate by lactate oxidase with the simultaneous formation of H<sub>2</sub>O<sub>2</sub> which subsequently oxidises 2, 4, 6‐tribromo 3‐hydroxy benzoic acid (TBHBA) in the presence of peroxidase. Oxidised TBHBA then reacts with 4‐amino antipyrine to obtain magenta colour (λ<sub>max</sub> = 523 nm). In the qualitative assay, colour change becomes visible in raw milk samples spiked with 300 mg lactate/L. The absorbance increases linearly up to 1000 mg/L. The method can be used for rapid assessment of the hygienic quality of milk.     

Tribological behaviour of proposed polymeric bearing materials

The aim of the present work is to introduce new polymeric bearing materials. The proposed polymeric composites are consisting of polyethylene (PE), polypropylene (PP) and polystyrene (PS) and filled by fibres of polytetrafluoroethylene (PTFE) in concentration up to 25 wt.% as well as different types of natural oils such as (corn oil, olive oil, paraffin oil, glycerin oil, castor oil and sunflower oil) in concentration up to 10 wt.%. The frictional behavior of the proposed composites and wear resistance are investigated at different values of applied load. Based on the experimental observations, it was found that for composites free of oil, friction of PS and PE specimens decreased, while friction of PP specimens slightly increased with increasing PTFE content. PP composites filled by corn oil showed slight friction increase. Besides, friction coefficient displayed by PS and PE specimens filled by glycerin oil decreased with increasing oil content, while friction coefficient displayed by PP specimens showed consistent trend. It was noted that, PE filled with 7.5% glycerin oil and 20 wt.% PTFE displayed the minimum value of friction coefficient (0.07). This friction coefficient values recommend those composites to be used as bearing materials. PE filled by glycerin oil displayed relatively lower friction values due its common known good lubricating property. Friction of PE composites filled by paraffin oil drastically decreased with the increasing oil content. PP composites showed the lowest wear values. In addition to that, it was shown that wear displayed by composites filled by glycerin oil was higher than that containing corn oil, while wear of the tested composites filled with olive oil showed lower values than that displayed by corn oil filled composites. Composites containing 5.0–7.5% paraffin oil content showed good wear resistance which recommends them to be used as bearing material. Wear of PP, PS and PE composites filled with sunflower oil and 15 wt.% PTFE drastically decreased with increasing oil content. The minimum wear was displayed by PP and PE composites filled with 10% oil content.     

新集矿区煤层气综合利用可行性研究

针对新集矿区煤层气资源丰富、适合进行大规模抽采的特点,提出两种资源综合利用可行性方案:方案一为新集一矿和新集二矿集中共建一只储气罐集中向外供气;方案二为两矿各建一只储气罐分别向外供气。通过对两种方案的经济和技术比较,结果表明,采用方案一两矿共用一只储气罐集中向外供气,无论在经济上还是技术上都较方案二合理,且符合目前的矿区实际现状。     

Experimental investigation of a thermoacoustic refrigerator driven by a standing wave twin thermoacoustic prime mover

The objective of this study is to analyse the performance of thermoacoustic refrigerator (TAR) measured in terms of hot end temperature and temperature difference across refrigerator stack with two different spacing namely 0.4 mm and 0.8 mm and stack used in refrigerating section was made of low thermal conductivity materials namely Mylar sheet and photographic film & the experiments were carried out at 1 MPa pressure using helium as working fluid. High powered acoustic wave with frequency of 460 Hz and pressure amplitude of <math><mo is="true">?</mo></math>0.07 MPa was obtained from twin thermoacoustic prime mover (TAPM) and this acoustic wave produced temperature difference of 16 °C across the Mylar sheet stack made of 0.4 mm spacing in refrigerator section. From this study, it has been inferred that twin TAPM can act as efficient drive for TAR.     

输油泵性能监测与故障分析

对输油站场输油泵经常出现的故障进行了分析,指出性能监测和故障分析方法不当是其主要因素,提出了在线监测和故障诊断系统方法,并对此系统进行了详细介绍。现场应用表明,在线监测和故障诊断系统方法具有良好的推广应用前景。     

基于近似l0范数的稳健稀疏重构算法

针对测量值受噪声污染的稀疏重构问题,本文提出了稳健近似l0范数最小化算法.该算法首先利用反正切函数近似l0范数,然后建立基于近似l0范数的含噪稀疏重构模型,最后通过拟牛顿法求解该模型,并分析了算法的收敛性.数值仿真表明,本文提出的算法重构稀疏向量时需要较少的测量值,且具有较高的计算精度.     

东濮凹陷基准面变化对砂体发育的控制作用分析

通过基准面变化的研究,分析了其对砂体发育的控制作用,认为东濮凹陷沙三段沉积时期基准面变化频繁．变化频率大于1000次／Ma,这种频繁变化导致沙三段中单砂层厚度较小,砂泥岩频繁互层。东濮凹陷古近系基准面变化旋回具典型“旋回含旋回”的特点,沉积物随基准面的变化不断迁移,在四级层序的高位域和低位域形成富集．四级层序界面对储层有比较明显的控制作用,界面附近砂岩比较发育,而且油气也富集,是油气勘探中要寻找的重点目标。     

出口纺织服装安全卫生项目抽查结果分析与思考

通过出口服装及其面料安全卫生项目抽查结果，分析其存在的问题，提出应对国际市场绿色技术壁垒的措施。