超声提取蜂胶黄酮的研究

蜂胶黄酮是蜂胶的主要活性成分,具有抗氧化、抗菌等多种功效。优化蜂胶黄酮的超声提取工艺,为蜂胶产品的开发与利用提供了理论依据。首先进行了单因素试验,研究超声功率、超声时间和乙醇浓度这三个因素分别对蜂胶黄酮提取得率的影响。在此基础上,再采用响应面法优化蜂胶黄酮的超声提取条件。研究结果表明,影响蜂胶黄酮提取得率的主次因素依次是超声时间、乙醇浓度和超声功率。当超声功率为150 W、超声时间为16 min、乙醇浓度为86%时,蜂胶黄酮提取得率实际最大可达到21.10%±0.075%(n=3)。经本实验分析可知,湖北孝感蜂胶属于蜂胶中的优等品。相比于其他超声提取蜂胶黄酮的方法,该实验的超声提取方法具有提取温度低、提取时间短的优势。     

超声协同静电场提取黄花菜中总黄酮的研究

在自发研究的提取装置的基础上,通过单因素试验,比较超声协同静电场辅助提取和单独使用超声辅助提取黄花菜黄酮的提取效率;采用正交试验,探索超声协同静电场辅助提取黄花菜总黄酮的最优工艺。结果表明:超声协同静电场提取比超声辅助提取可以获得更高的黄花菜黄酮提取得率;超声协同静电场的最佳提取因素组合是静电场为7 kV,超声电功率为600 W,乙醇体积浓度为50%,提取时间为40 min,固液比1:25以及提取温度55℃由单因素试验确定。在最佳因素的条件下,黄花菜黄酮的提取得率最高可达1.48%。通过探讨超声和静电场的作用机理,从理论上解释为超声具有破壁作用,静电场具有破膜作用。两者结合共同作用时,静电场可视为超声场的一个随机干扰,加强了超声空化效应,强化了破坏植物细胞组织,获得了更高的黄酮提取得率。     

对锁阳中黄酮最佳提取工艺的研究

目的优选锁阳中黄酮的最佳提取工艺。方法分别以总黄酮含量、浸膏得率、儿茶素含量和抗自由基活性为评价指标,选择物料比（A）,提取时间（B）和提取次数（C）为考察因素,采用正交实验L9（34）优选锁阳中黄酮的最佳提取工艺。结果锁阳中黄酮的最佳提取工艺条件为：以60％的乙醇为提取溶剂,物料比为1：14,提取时间3．0h,共提取1次。结论优选工艺条件可为新药研究和工业化生产提供参考。     

中药黄酮的提取、分离纯化方法概述

近几年黄酮备受关注,本文详细介绍了中药黄酮的提取、分离纯化的各种方法。     

桑叶黄酮超声提取最佳工艺条件研究

目的：研究超声技术提取桑叶黄酮的工艺条件。方法：采用L。（3。）正交实验法对超声提取桑叶黄酮的因素进行考察，以总黄酮含量为考核指标，确定最佳提取条件．结果；优化的提取工艺为：加药材15倍量的50％乙醇超声提取3次，每次40分钟。结论；该提取工艺科学合理、可行性强。     

桑叶黄酮超声技术提取工艺研究

目的：研究超声技术提取桑叶黄酮的工艺条件。方法：采用L9（34）正交实验法对超声提取桑叶黄酮的因索进行考察，以总黄酮含量为考核指标，确定最佳提取条件。结果：优化的提取工艺为：加药材15倍量的50％乙醇超声提取3次，每次40分钟。结论：该提取工艺科学合理、可行性强。     

桑叶黄酮提取及其含量测定

本文采用沸水提取桑叶,水提取液经D-101大孔吸附树脂吸附富集,然后用80%的乙醇洗脱,对桑叶中的总黄酮进行提取、精制;对提取物进行水解,进行高压液相色谱分析,结果证实桑叶含有黄酮甙,其甙元为槲皮素和山奈酚,含量试验表明桑叶中总黄酮甙含量为1.26%,上述工艺所得精制桑叶总黄酮中总黄酮甙含量为44.15%。     

响应面法优化甘肃平凉牡丹籽超声-微波提取工艺的研究

以甘肃平凉油用牡丹为籽原料,以单因素实验结果作为研究基础,对超声-微波协同提取时间、超声、微波的功率、温度、料液比等影响因素进行试验,应用中心组实验设计方案,以牡丹籽得油率为响应值,进行超声-微波协同萃取牡丹籽油,找出了影响提取牡丹籽油的交互因素：以石油醚为提取溶剂时,选择1∶6～1∶9范围内的料液比,用400～800 W的微波在30℃～50℃下辐照6～8 min,同时在480～560 W超声功率下振荡10～20 min,牡丹籽粗油得油率最高为34%,微波温度和功率、超声功率和振荡时间、超声功率和料液比以及振荡时间和料液比之间交互作用显著。     

图像识别技术在S355J2W钢板带状组织评定中的应用

采用图像识别技术对动车组零部件用S355J2W钢板的带状组织进行评定。通过摄像头从显微镜中获取试样显微组织的图像,采用数字图像处理方法对图像进行处理,对图像进行特征物提取和特征物计数,最后计算出评定结果。结果表明:S355J2W钢板带状组织评定结果相对精度小于30%,符合带状组织评定标准要求;采用图像识别技术减少了主观因素的影响,提高了工作效率。     

微波促进甘草酸的提取

微波辅助萃取技术近年来不断用于药物有效成分的提取,本实验以新疆甘草的粗粉为原料,用乙醇作溶剂,用微波辅助萃取法提取甘草酸,并研究了不同实验条件,如作用时间、不同的乙醇浓度、液固比、温度和微波功率对微波辅助萃取甘草酸的影响,得到一优化条件：50％的乙醇溶液作溶剂,微波功率300W,作用时间10min,温度70℃,液固比20：1（ml／g）。与传统提取法进行比较,得出微波辅助萃取甘草酸比传统方法更节约时间,效率更高。     

Optical system for tablet variety discrimination using visible/near-infrared spectroscopy

An optical system based on visible/near-infrared spectroscopy (Vis/NIRS) for variety discrimination of ginkgo (Ginkgo biloba L.) tablets was developed. This system consisted of a light source, beam splitter system, sample chamber, optical detector (diffuse reflection detector), and data collection. The tablet varieties used in the research include Da na kang, Xin bang, Tian bao ning, Yi kang, Hua na xing, Dou le, Lv yuan, Hai wang, and Ji yao. All samples (n=270) were scanned in the Vis/NIR region between 325 and 1075 nm using a spectrograph. The chemometrics method of principal component artificial neural network (PC-ANN) was used to establish discrimination models of them. In PC-ANN models, the scores of the principal components were chosen as the input nodes for the input layer of ANN, and the best discrimination rate of 91.1% was reached. Principal component analysis was also executed to select several optimal wavelengths based on loading values. Wavelengths at 481, 458, 466, 570, 1000, 662, and 400 nm were then used as the input data of stepwise multiple linear regression, the regression equation of ginkgo tablets was obtained, and the discrimination rate was researched 84.4%. The results indicated that this optical system could be applied to discriminating ginkgo (Ginkgo biloba L.) tablets, and it supplied a new method for fast ginkgo tablet variety discrimination.     

A method for extraction and quantification of Ginkgo terpene trilactones

A method was developed for the extraction and quantification of pharmacologically active terpene trilactones (ginkgolides, bilobalide) from the tissues of Ginkgo biloba L. and pharmaceutical ginkgo products by RP-HPLC, based on the theory of terpene trilactones ionization. Four ginkgolides (GA, GB, GC, GJ) and bilobalide (BB) from both the ginkgo leaves and commercially available ginkgo extracts were quantitatively extracted by using this method. The recovery rate of the method was 97.5-100% with RSD of 1.2-2.8%. The detection limit was 0.05-0.1 microg, and the linear range was 0.1-12 microg. This detection limit represents a marked improvement over previously reported methods, suggesting the new method is a viable technique for routine analysis of ginkgo terpene trilactones in natural and commercial samples. The method reported by van Beek et al. in 1991 (van Beek, T. A.; Scheeren, H. A.; Rantio T.; Melger, W. C.; Lelyveld, G. P. J. Chromatogr. 1991, 543, 375-387.) was used as a reference method to monitor the accuracy of extraction and analysis in this study. SSI-MS technique was used to identify isolated target components. Carbohydrase treatment and solubility of terpene trilactones in various solvents were also discussed.     

Antifungal effect of green synthesised silver nanoparticles against Setosphaeria turcica

Green synthesis of silver nanoparticles (AgNPs) is an interesting issue of the nanoscience and nanotechnology due to their unique properties. In the present study, Ginkgo biloba L. leaf extract was used to synthesise AgNPs. The effects of quantity of leaves, concentration of Ag nitrate (AgNO₃), reaction temperature, and pH were studied to discover the optimal synthesis system. In addition, antifungal effect of AgNPs against Setosphaeria turcica was measured through inhibition zone method. The optimal biosynthesis system contained 15 g of leaf, 8 mM AgNO₃, and 80°C at pH 9.0. Under mentioned conditions, the resulting synthesised NPs were nearly spherical, with an average size of 14 nm. In tests, AgNPs synthesised at different pH resulted in different inhibition zones, diameters increased gradually at pH from 3.0 to 11.0, while antifungal effect reached maximum at 9.0. Results of this study offer a new approach for biological control plant pathogenic fungi, and it has potential application for screening novel fungistats with high efficiency and low toxicity.Inspec keywords: antibacterial activity, silver, nanoparticles, nanobiotechnology, pHOther keywords: antifungal effect, green synthesised silver nanoparticles, Setosphaeria turcica, nanoscience, nanotechnology, Ginkgo biloba L. leaf extract, reaction temperature, pH, inhibition zone method, inhibition zones, mass 15 g, temperature 80 degC, size 14 nm, Ag     

超声强化溶剂提取车前草中总黄酮的研究

采用超声技术对车前草中总黄酮提取进行强化,选择料液比、超声提取时间、提取温度、超声功率四因素进行正交实验,得出影响总黄酮提取率大小的次序先后为：提取温度〉超声功率〉超声提取时间〉料液比。在实验参数的基础上,为了获得较高的提取率和节省溶剂用量,各因素的优化工艺参数为：料液比1：20,超声提取时间30min,超声提取温度为50℃,超声功率为200W,在这个最佳条件下试验,总黄酮的提取率为0．645％。相对常规回流提取法而言,采用超声法提取具有快速、节省溶剂、节省时间、提取的有效成分含量较高等优点。     

LC-MSn methods for saccharide characterization of monoglycosyl flavonoids using postcolumn manganese complexation

A simple tandem mass spectrometry method for differentiating isomeric monoglycosyl flavonols, flavones, and flavanones using manganese complexation is reported. Dissociation of the [Mn(II) (L) (L - H)]+ and [Mn(II) (L)2 (L - H)]+ species provides unique fragment ions that allow the identification of the saccharide moiety as glucose, galactose, arabinose, or xylose. The glycosylation site of the flavonoid can also be determined by the fragmentation pathways of the Mn complexes. The Mn complexation method was adapted for on-line liquid chromatography-mass spectrometry analysis and tested using flavonoid extracts from Fuji apples (Malus domestica Borkh. cv. Fuji) and red onions (Allium cepa L.). Using fragmentation data obtained from collisional activated dissociation of the deprotonated flavonoid glycosides and their Mn complexes, the major flavonoid species in these extracts were identified.     

食品包装用功能性添加剂灯心草黄酮含量测定的研究

研究了紫外光分光光度法测定食品包装用功能性添加剂--灯心草黄酮苷含量的方法,以芦丁为参照品,测量波长为359 nm,平均回收率为100.01%,精密度为1.72%,说明紫外分光光度法是一种较理想的测定方法.     

微槽道表面喷雾冷却的实验研究

本文建立了以蒸馏水为工质的开放式喷雾冷却系统,研究了工质体积流量、槽道宽度、槽道高度对喷雾冷却系统换热性能的影响。结果表明:保持槽道高度为0.8 mm,喷雾流量为0.45 L/min时,随着槽底宽度从4 mm减小至1 mm,传热系数增加了41%;而当喷雾流量为1.25 L/min时,表面传热系数仅增加了8.5%,因此减小槽底宽度对喷雾冷却效果有一定的促进作用,但大流量时并不明显;保持槽底宽度为2 mm,改变槽道高度,当喷雾流量为0.45 L/min时槽道高度对热沉表面的换热影响较大,存在最优槽道高度(0.8 mm),此时热流密度和表面传热系数分别为198.5 W/cm~2、2.75 W/(cm~2·K),与光滑面相比增加了21.25%和30.95%,且存在最低表面温度;而当喷雾流量增至1.25 L/min时,喷雾冷却效果随着槽道高度的增加而持续增加。在以上基础上推导了微槽表面喷雾冷却强化换热机理,得出反映槽道尺寸对换热影响的微槽群表面无量纲准则方程。     

Microstructure and wear properties of spark plasma sintered 316L-30W composites

ABSTRACT

316L-30W composites were successfully fabricated via spark plasma sintering at 1550°C to evaluate their potential as the interlayer between W and 316L stainless steel in fusion reactors. The effect of holding time on the microstructure and its subsequent effects on the fracture morphology and wear properties of the composites were investigated. The results show that more W particles melted and reacted with 316L steel as the holding time increased from 1 to 5 min. The generation of voids was mainly caused by the differences in diffusivity and the coefficient of thermal expansion between W and 316L. The 316L-30W composite held for 3 min had a smaller and more stable friction coefficient, indicating that its interface was firmly bonded and homogeneous.

This paper is part of a thematic issue on Nuclear Materials.     

Optoacoustic trace-gas monitoring with near-infrared diode lasers

An inexpensive resonant optoacoustic monitoring system using near-infrared laser diodes was developed. It was demonstrated that wavelength modulation at the resonance frequency of the cell provides a superior signal-to-noise ratio compared with amplitude modulation and eliminates background drifts and fluctuations. The system was tested out on ammonia. Its sensitivity is 8 parts in 10(9) (S/N = 1) at atmospheric pressure, which corresponds to a minimum detectable absorption coefficient of approximately 3.5 × 10(-11) cm(-1) W(-1). The pressure dependence of the optoacoustic resonance was also investigated. The monitor can be used as a continuous flow-through system up to a flow rate of approximately 3.5 L/min.     

椰壳活性炭基超级电容器的研制与开发

为了开发体积小巧、大功率放电性能优良的超级电容器,选用比表面积1 660m2/g的椰壳活性炭,采用扣式电池结构,通过恒电流充放电、电化学阻抗谱、扫描电子显微镜等方法对其用于超级电容器的性能进行了考察。结果表明,选用椰壳活性炭的最大比容量为79F/g,大功率放电性能优良。继而采用该种椰壳活性炭为电极活性物质,以6m o l/L KOH为电解液,外包装采用涂覆防腐蚀尼龙层的铝箔袋软包装组装了1V、70F的超级电容器,外形尺寸为35mm×43mm×6mm。测试结果表明其比功率密度为170W/kg或330W/L,比能量密度1W h/kg,大功率放电特性较好。