温度对单甘酯的合成起关键作用

在无溶剂体系中以脂肪酶催化棕榈油的甘油解反应合成单甘酯时，发现温度对单甘酯的产率起关键作用。反应存在一临界温度，低于临界温度时单甘酯的平衡浓度高于６０％，而高于临界温度时单甘酯含量只有３０％左右。临界温度与油脂的种类有关；通过测定各种油脂的临界温度并与其熔点相比较，结合反应现象学及反应进程中反应混合物各组分含量的变化，提出了临界温度的存在机理。     

液压压榨澳洲坚果粕酶解制备多肽工艺优化

以液压压榨澳洲坚果粕为原料,分析了其常规营养成分含量与氨基酸组成。采用碱性蛋白酶与中性蛋白酶催化酶解澳洲坚果粕蛋白制备多肽。以水解度为指标,利用单因素试验与正交试验考察了各因素对澳洲坚果粕蛋白水解度的影响。结果表明：液压压榨澳洲坚果粕中含有32.25%的蛋白质,17 种氨基酸,含量为25.05%。碱性蛋白酶各因素对澳洲坚果粕蛋白水解度影响的主次顺序为：酶解时间＞酶解温度＞加酶量＞酶解pH值＞底物质量浓度,最佳工艺条件为：酶解温度60 ℃、酶解时间3.5 h、底物质量浓度110 g/L、酶解pH 8.0、加酶量2 400 U/g,在此条件下水解度达到了22.83%。中性蛋白酶各因素影响水解度的主次顺序为：加酶量＞酶解时间＞底物质量浓度＞酶解温度＞酶解pH值,最佳工艺条件为酶解温度55 ℃、酶解时间3.5 h、底物质量浓度100 g/L、酶解pH 7.0、加酶量3 200 U/g,水解度达到了22.78%。碱性蛋白酶与中性蛋白酶各因素对澳洲坚果粕蛋白水解度的影响均达到了极显著水平（P＜0.01）。在最佳工艺条件下,碱性蛋白酶酶解液压压榨澳洲坚果粕制备多肽的效果优于中性蛋白酶。     

澳洲坚果青皮不同极性溶剂分步提取物功能成分与抗氧化活性及其相关性分析

采用80％(体积分数,下同)乙醇超声提取澳洲坚果青皮,依次用石油醚、氯仿、乙酸乙酯、正丁醇4种不同极性溶剂对其提取物进行分步萃取,剩余为水溶解物,分别得到80％乙醇提取物、石油醚提取物、氯仿提取物、乙酸乙酯提取物、正丁醇提取物与水溶解物6种溶剂提取物,测定其总酚、黄酮、多糖等主要功能成分质量分数与抗氧化活性,并分析其相...     

High-gravity intensified iron-carbon micro-electrolysis for degradation of dinitrotoluene

The application of iron–carbon (Fe–C) micro-electrolysis to wastewater treatment is limited by the passivation potential of the Fe–C packing. In order to address this problem, high-gravity intensified Fe–C micro-electrolysis was proposed in this study for degradation of dinitrotoluene wastewater in a rotating packed bed (RPB) using commercial Fe–C particles as the packing. The effects of reaction time, high-gravity factor, liquid flow rate and initial solution pH were investigated. The degradation intermediates were determined by gas chromatography-mass spectrometry, and the possible degradation pathways of nitro compounds by Fe–C micro-electrolysis in RPB were also proposed. It is found that under optimal conditions, the removal rate of nitro compounds reaches 68.4% at 100 min. The removal rate is maintained at approximately 68% after 4 cycles in RPB, but it is decreased substantially from 57.9% to 36.8% in a stirred tank reactor. This is because RPB can increase the specific surface area and the renewal of the liquid–solid interface, and as a result the degradation efficiency of Fe–C micro-electrolysis is improved and the active sites on the Fe–C surface can be regenerated for continuous use. In conclusion, high-gravity intensified Fe–C micro-electrolysis can weaken the passivation of Fe–C particles and extend their service life.     

Approach and potential of replacing oil and natural gas with coal in China

China’s fossil energy is characterized by an abundance of coal and a relative lack of oil and natural gas. Developing a strategy in which coal can replace oil and natural gas is, therefore, a necessary and practical approach to easing the excessive external dependence on oil and natural gas. Based on the perspective of energy security, this paper proposes a technical framework for defining the substitution of oil and natural gas with coal in China. In this framework, three substitution classifications and 11 industrialized technical routes are reviewed. Then, three scenarios (namely, the cautious scenario, baseline scenario, and positive scenario) are developed to estimate the potential of this strategy for 2020 and 2030. The results indicate that oil and natural gas replaced by coal will reach 67 to 81 Mt and 8.7 to 14.3 Gm³ in 2020 and reach 93 to 138 Mt and 32.3 to 47.3 Gm³ in 2030, respectively. By implementing this strategy, China’s external dependence on oil, natural gas, and primary energy is expected to be curbed at approximately 70%, 40%, and 20% by 2030, respectively. This paper also demonstrates how coal, as a substitute for oil and natural gas, can contribute to carbon and pollution reduction and economic cost savings. It suggests a new direction for the development of the global coal industry and provides a crucial reference for energy transformation in China and other countries with similar energy situations.     

煤的表面处理及润湿性研究

煤炭是一种具有大分子网状结构的有机岩石,表面润湿性是其工业应用的重要物性参数。通过原煤及分别经过偶联剂和烷基化处理的煤样表面润湿性的定,对煤表面润湿性进行了初步研究,结果表明,分别经过偶联剂处理和烷基化处理的煤样,其润湿性有一定程度的改善,使煤样表面发生了改性,烷基化反应后煤样的红外测试结果也证明了这一点。     

煤中氯的赋存形态与释放特性的研究进展

从煤中氯的赋存形式、测定方法、释放特性和控制技术等方面,对国内外的煤中氯研究现状进行了评述。到目前为止,氯在煤中的赋存形式仍未有统一的结论,但都认为燃烧过程煤中氯主要以氯化氢的形式释放,将对燃烧设备燃烧区、加热器等部位产生腐蚀并污染环境。研究结果表明采用洗煤技术可以有效降低煤中的氯含量。     

微水体系中酶促合成己酸乙酯的研究

以Candidalipolytical脂肪酶在烷烃溶剂中催化合成白酒主体香料己酸乙酯。反应温度 36℃ ,己酸浓度 0 4mol/L ,己酸与乙醇摩尔比 1∶13,辛烷为溶剂 ,批次加入分子筛 ,加酶量为 15 0 0u/g己酸 ,反应 2 4h ,己酸转化率达 85 %     

煤的表面电位与表面官能团间的关系

测定了5种不同变质程度的典型中国动力煤在不同pH值的水介质中的ζ电位和用H₂O₂氧化后各煤种ζ电位的变化,得到了ζ电位等电点pH值;用FTIR定量表征了与煤表面电位有关的官能团以及被H₂O₂氧化后的变化;通过对模型化合物的ZINDO量子化学理论计算,得到了H⁺ 在煤表面的吸附能、相关化学键的键级、键长和净电荷分布.综合分析实验和计算的结果,确认了在水体系中煤的表面电荷为负电荷;煤的ζ电位等电点随煤化程度的提高有规律地升高;与煤表面ζ电位密切相关的负电性官能团主要是—OH基团;原煤经H₂O₂氧化后,—OH、和—COOH等官能团增多,煤表面负电性增加;H⁺在煤表面发生化学吸附,吸附能随着煤化程度的增加而增加.     

Sensor fault diagnosis of nonlinear processes based on structured kernel principal component analysis

A new sensor fault diagnosis method based on structured kernel principal component analysis （KPCA） is proposed for nonlinear processes. By performing KPCA on subsets of variables, a set of structured residuals, i.e., scaled powers of KPCA, can be obtained in the same way as partial PCA. The structured residuals are utilized in composing an isolation scheme for sensor fault diagnosis, according to a properly designed incidence matrix. Sensor fault sensitivity and critical sensitivity are defined, based on which an incidence matrix optimization algorithm is proposed to improve the performance of the structured KPCA. The effectiveness of the proposed method is demonstrated on the simulated continuous stirred tank reactor （CSTR） process.