Gas chromatographic method for the determination of hexaconazole residues in black tea

A highly reliable, quantitative and sensitive analytical method for determining the residues of the fungicide, hexaconazole in black tea is described. The proposed method is based on liquid-liquid extraction followed by gas chromatographic determination, using nitrogen phosphorus detector (GC-NPD) for the identification and quantitation of hexaconazole. The most was cleaned up by adsorption column chromatography using activated florisil. Performance of the method was assessed by evaluating quality parameters such as recovery value, repeatability, reproducibility, linearity and limits of detection and quantitation. When the method was assessed for repeatability, the percentage of recovery ranged between 86% and 96% while the relative standard deviation was between 0.30% and 2.35%. In studies on reproducibility the recovery ranged from 81% to 85% and relative standard deviation from 1.68% to 5.13%, implying that the method was reliable. A field trial was conducted to verify the application of this method with real samples. Results prove that the validated method was suitable for extracting hexaconazole residues.     

导师制·午后茶·住宿学院与一流大学的人才培养

文章对导师制、午后茶和住宿学院对一流大学人才培养的影响进行了探讨,并据此说明研究世界一流大学不仅要关注有形的人才培养方式,更要关注蕴含在这些人才培养方式背后或之中的隐性力量对一流大学人才培养和一流大学形成与发展的影响.     

茶叶香气成分的研究--乌龙茶与鲜茶香气成分的比较

报道了用同时蒸馏-萃取装置分别提取乌龙茶与鲜茶香气成分，测得乌龙茶的香气成分含量为3．65％．鲜茶的香气成分含量为2．40%。用GC／MS法分别从乌龙茶与鲜茶香气成分中分离并确定出42种和19种化学成分，并对香气化学成分及含量进行了对比。     

十九世纪四五十年代华茶出口贸易缘何形成黄金期

我国以“茶的故乡”已久享盛名,然而至十九世纪的四五十年代才形成了华茶出口的黄金期。华茶出口所以如此兴盛,有国际和国内两个层面的原因,具而言之,有政策方面的因素,亦有供求关系方面的影响。     

茶树中茶多糖含量测定及提取研究

考察了温度、酸碱盐介质及微波提取对茶多糖提取的影响，实验表明，用氯仿、乙酸乙酯将茶叶、茶树枝梢、茶树根粉末进行回流提取之后，再用质量分数2％的碳酸钠溶液在微波提取器中浸提3次，可将茶多糖及其它有效成分充分提取出来，其中茶树根多糖提取率高达7．25％，茶树枝梢可达6．34％，粗老叶子可达6．07％。     

"茶"的文化修辞意义

茶不仅是饮品,从现代汉语广义修辞学的角度来看,它在婚恋、礼仪、宗教、艺术审美几个方面有着丰富的文化修辞意义,是一个意蕴丰厚的文化修辞原型.     

王旭烽的文化理念写作——论杭嘉和形象与儒家文化的关系

王旭烽的长篇小说《茶人三部曲》以"茶"作为载体,从文化角度切入来表现太平天国运动后期至20世纪末的百数十年的社会历史变迁,塑造了众多个性丰满的人物形象,演绎出知识分子在社会历史变迁中的心灵历程,具有"史诗"的壮美宏大。其中杭嘉和形象以其独特深厚的文化内涵给读者留下了深刻印象,集中体现作者的价值取向和审美理想。杭嘉和从个体修养、家庭、社会诸方面体现出文化对人格塑造的决定性影响,尤其是在中国传统文化特别是儒家文化传承中理想人性的实现,揭示了作家文化创作理念及社会道德立场。     

中国茶文化的活化石——擂茶

擂茶是中国客家人的传统饮茶习俗,也是中国古代饮茶习俗的延续。通过对擂茶的起源、制作方法、药理作用及其发展前景的研究,可以增强我们对客家人饮茶习俗及其文化内涵的了解。     

论茶文化对旅游业的牵引作用

茶自人类发现以来，早已淡化了最初的饮食意义。几千年发展所形成的茶化体系，不仅包含了我国传统思想、伦理、道德乃至世界观意识，而且反映了人们对人生信仰、崇高境界的追求。普洱县以普洱茶闻名于海内外，其历史悠久，化底蕴深厚，具有很高的旅游价值。但由于当地仅把茶叶生产作为产业方向，忽视了其自身蕴涵的化价值，使其综合效益尚未得到充分体现。在云南旅游业发展良好的背景条件下，在云南将建成民族化大省的召引下，普洱人应着力挖掘其特有的茶化潜力，牵引地方旅游业迅速发展，使已出现滑坡的普洱茶再度辉煌。     

Influence of green tea polyphenols on mitochondrial permeabi lity transition pore and Ca2+ transport

The authors investigated the influence of green tea polyphenols (GTPs) on the liver mitochondria permeability transition pore (PTP) opening through mit ochondria swelling and change of mitochondria membrane potential. The data showe d that GTPs had obvious protective effect on the Ca2+-induced PTP opening in a d ose-dependent manner detected by mitochondria swelling. The results were obtain ed by measuring the change of mitochondria membrane potential through Rh 123. Further experiments were conducted to examine the detailed influence of GTP s on Ca2+import and export of mitochondria. The results showed that GTPs h ad rem arkably inhibitory effect on the Ca2+-induced Ca2+ import in mitoch ondria; and t hat they could accelerate Ca2+-release from mitochondria. Our data provid e an al ternate interpretation of the potent protective function of GTPs on cell against apoptosis.