基于近红外光谱的大豆油质量快速检测技术应用研究

利用近红外光谱快速检测大豆油脂的过氧化值和酸值,分析发现大豆油脂的过氧化值和酸值在近红外光谱区域有特征吸收峰,通过对比分析,优选出大豆油脂过氧化值特征波段为4500~9000 cm^-1,大豆油脂酸值的特征波段为4500~5000 cm^-1,采用小波变换对光谱去噪并利用PLS建立了预测模型,大豆油脂过氧化值和酸值模型的相对标准偏差RSD分别为3.513%和3.629%,准确度与化学方法相近,说明利用近红外光谱分析技术快速检测大豆油脂主要指标是可行的。     

Production of vitamin B12 in genetically engineered Propionibacterium freudenreichii

Since the chemical synthesis of vitamin B12 requires more than 70 steps, the production of vitamin B12 has been achieved by microorganism fermentation with additional brief chemical modifications. In an effort to increase the productivity of vitamin B12, we tried to express 10 genes belonging to the hem, cob and cbi gene families involved in the synthesis of vitamin B12 in Propionibacterium freudenreichii, which is a known producer of vitamin B12. In a recombinant P. freudenreichii clone that harbored the expression vector containing a cobA, cbiLF, or cbiEGH, we obtained an increase in vitamin B12 production of 1.7-, 1.9-, and 1.5-fold higher, respectively, than that in the microorganism without any cloned genes in the expression vector pPK705. The cobU and cobS genes caused a slight increase in the production of vitamin B12. Furthermore, we achieved multigene expression in P. freudenreichii. In a recombinant P. freudenreichii clone that harbored an exogenous gene, hemA, from Rhodobacter sphaeroides and endogenous hemB and cobA genes, we successfully achieved the production of about 1.7 mg/l vitamin B12, 2.2-fold higher than that produced by P. freudenreichii harboring pPK705.     

Brewing of glucuronic acid-enriched apple cider with enhanced antioxidant activities through the co-fermentation of yeast (Saccharomyces cerevisiae and Pichia kudriavzevii) and bacteria (Lactobacillus plantarum)

Co-fermentation using yeast (Saccharomyces cerevisiae and Pichia kudriavzevii) and the bacteria (Lactobacillus plantarum) as starters isolated from spontaneous sourdough was conducted for the brewing of glucuronic acid (GlcA)-enriched apple cider. The concentration of GlcA in the apple cider co-fermented for 14 d with commercial S. cerevisiae and L. plantarum was 37.7 ± 1.7 mg/mL while a concentration of 62.8 ± 3.1 mg/mL was recorded for fermentation with P. kudriavzevii and L. plantarum, which was higher than the corresponding single yeast fermentation. The co-fermented apple cider revealed higher 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of 171.67 ± 0.79 µg trolox equivalents (TE)/mL using P. kudriavzevii and L. plantarum, compared to the control (143.89 ± 7.07 µg TE/mL) just using S. cerevisiae. Thus, the co-fermentation of S. cerevisiae and L. plantarum and P. kudriavzevii and L. plantarum provided a new strategy for the development of GlcA-enriched apple cider with enhanced antioxidant capacity.     

智能变电站ICD/CID/SCD模型内容差异检查方法及工具

针对目前智能变电站中ICD/CID之间与SCD中对应IED内容的差异不宜查找的问题,研究了一种多种文档内容差异检查方法及其工具。针对SCD、ICD、CID的语法特点,采用堆栈技术,获得各节点的开始行与结束行号。以两侧节点为完整单位,对节点的标签名和关键属性,进行两侧的交叉检查,找出两侧相同节点,并给出其中非关键属性的顺序错乱、属性值不同、内容不同等多种差异情况。能够对两侧同名节点的开始与结束行进行并列显示,直观同步地对照展示出两个文件中各种差异细节,并能切换到原始文档的相应位置。多个变电站的运行实例验证了该差异检查方法及其工具的有效性。该工具能够提高多个不同文档之间差异检查的准确性和效率。     

Comparative GC/MS analysis of essential oils extracted by 3 methods from the bud of Citrus aurantium L. var. amara Engl

A comparative study of steam distillation extraction (SDE), reflux extraction (RE), and ultrasound-assisted extraction (USE) was conducted for the extraction of essential oils from the bud of Citrus aurantium L. var. amara Engl. Each method was evaluated in terms of qualitative and quantitative composition of the isolated essential oil by gas chromatography/mass spectrometry (GC/MS). The extract yields of essential oil were 0.16%, 2.18%, and 2.34%, respectively. A total of 82 compounds were identified by GC/MS. The main components obtained by SDE were terpinen-4-ol (20.98%), dipentene (11.67%), terpinene (9.24%), those by RE were palmitic acid (20.61%), 2-chloroethyl linoleate (14.54%), tetracosane (12.26%), and α-linolenic acid (11.24%), and those by USE were tetracosane (11.32%), heneicosane (11.06%), and palmitic acid (8.76%). Comparative analysis indicated that SDE was favorable for the extraction of monoterpene hydrocarbons, sesquiterpene hydrocarbons, alcohols, and carbonyl compounds, RE and USE had certain advantages in the extraction of aliphatic saturated hydrocarbons, organic acids, and esters. It is concluded that different extraction methods may lead to different yields of essential oils; the choice of appropriate method is very important to obtain more desired components with higher physiological activities. PRACTICAL APPLICATION: C. aurantium oils from different plant parts have great economic, medicinal, and nutritional values because of their wide-spectrum biological activities. The essential oil from C. aurantium L. var amara is one of the best C. aurantium oils. The data presented in this article will help us understand the relationship between essential oils and its extraction methods and know more about the aromatic components of Citrus aurantium bud. The methods established in this study will provide useful reference information for further studies, and offer essential oil industries with helpful guidance in practice.     

PROTOS M5卷接机组梗签输送装置的优化设计

为解决PROTOS M5卷接机组梗签输送装置中输送管道容易堵塞问题,通过Solid Works建立管道模型,利用Fluent分析软件模拟空气在管道中流动的形态,对流体在管道中的压力和流线进行分析,得到梗签输送管道的堵塞原因并对该装置进行了优化设计:将封闭式弯管改为开放式振槽,缩短输送管道长度;增加切碎梗签功能,将较长梗签切断,避免过长梗签卡在管道弯曲处;采用直管连接梗签箱与集中负压源,减少负压损失。结果表明:1管道在最大弯曲处、同一截面上出现螺旋式流动时,或在最大弯曲处出现流速为零时,以及管道压力损失过大时,均容易造成管道堵塞。2改进后管道压力和流线分布均匀,管道压力损失由452.8 Pa减小到245.5 Pa,有效解决了梗签输送管道堵塞问题。     

绿色煤炭——煤炭的生物降解转化

分析和阐述了绿色化学生物技术在煤炭生物转化领域应用的重要性及其应用.生物技术与矿业技术相结合将为传统的矿业工程技术领域注入崭新活力,必将促进矿业技术获得新的更快发展.     

Microwave-assisted synthesis of graphene-supported Pd1Pt3 nanostructures and their electrocatalytic activity for methanol oxidation

This work reports the development of a facile, one-step microwave heating method for the synthesis of graphene-supported Pd₁Pt₃ (Pd core/Pt shell) electrocatalysts. The structure and composition of the synthesized nanocomposites were characterized via transmission electron microscopy and atomic force microscopy as well as energy-dispersive X-ray, X-ray powder diffraction, FTIR, and Raman spectroscopies. Using voltammetry, the electrocatalytic characteristics of the graphene-supported Pd₁Pt₃ nanostructures were evaluated for the oxidation of methanol as a model reaction. The results show that the introduction of graphene increases the electrochemically active surface area of the Pd₁Pt₃ nanostructures. As compared to the unsupported Pd₁Pt₃ electrocatalyst, the graphene-supported Pd₁Pt₃ electrocatalyst exhibited 80% enhancement of the electrocatalytic specific mass current for the oxidation of methanol. This method may serve as a general, facile approach for the synthesis of graphene-supported bimetallic PtM electrocatalysts with increased utilization of the Pt metal, which is expected to have promising applications in fuel cells.     

Synthesis and characterization of superhydrophobic wood surfaces

Superhydrophobic films were developed on wood substrates with a wet chemical approach. Growth of zinc oxide (ZnO) nanorods was found differentially in the cross‐sectional walls and inner lumenal surfaces. The surface roughness of the prepared films on the inner lumenal surface conformed to the Cassie–Baxter wetting model, whereas the roughness across the microsurface of the cell wall was in conformity with the hydrophobic porous wetting model. The space between the ZnO nanorods and the microstructure of the wood surface constituted the nanoscale and microscale roughness of the ZnO nanofilm, respectively. The water contact angle of the prepared wood surfaces was up to 153.5°. In the prepared films, monolayers of stearic acid molecules were self‐assembled on the ZnO nanorods, which in turn, were attached to the wood surface via dimeric bonds. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

气-液-固三相流化床冷态实验

以氮气为气相、蒸馏水为液相、铜粉为固相构建了的气-液-固三相流化床冷态实验装置,流化床反应器内径为50 mm、高为500 mm.采用Hilbert-Huang Transform分析了布风板上表面处压力脉动信号,考察了布风板压差和床内两固定测点间压差随气体流速的变化关系,使用降速法得到了气-液-固三相流化床的最小流化速度,并通过同步图像采集验证了该最小流化速度.结果表明:气体流速为14.85 mm/s时,固体颗粒之间碰撞剧烈,气、液、固三相混合均匀;随着气体流速的增加,两固定测点间压降呈现先降低,后增加,最后又降低的变化趋势;气-液-固三相流化床的最小流化速度约为17.4 mm/s.