苹果斑点落叶病研究

对北京地区苹果斑点落叶病研究得出,病原菌Alternaria mali Roberts强毒菌系是苹果斑点落叶病严重发生的主要原因.各果园病原菌强毒菌系发生率和致病性有差异.室内毒力测定和田间药剂防治试验结果表明,50%扑海因、70%代森锰锌、1.5%多抗霉素和10%宝丽安均有很好的抑菌效果.多抗霉素和宝丽安加入1%硼酸可以显著提高药效,并且硼酸本身对菌落生长有一定抑制作用.提出“重点保护春梢叶片,兼顾秋梢叶片”的防病原则.     

种子发芽纸测试报告

发芽纸是种子发芽试验必需的材料。国内首次研制成的专用种子发芽纸具有吸水快、持水性好、韧度大、厚度适中等特点。该纸无毒性、幼根不易穿透,且成本低。它既可衬垫于发芽容器中,更宜作发芽纸卷。试用结果表明,它能广泛适用于农作物、蔬菜、牧草、瓜、豆类等各种种子的发芽试验。在植物种子科学研究和生产实际中,经常需要进行种子发芽试验,一般的种子发芽试验常采用纸张作为发芽床。为使种子正常发芽和便于检查发芽结果,要求发芽纸有良好的理化特性。对此,国际种子检验协会对种子发芽纸的质地、灰分、韧度和吸水性能等有明确的规定指标,如要求纸张有足够强度,在发芽试验操作中不致撕破;质地要通透多孔,但幼根不能穿入纸中。国外已有不少国家都生产有专用的种子发芽纸,而国内至今还没有一种专门供种子发芽用的纸张,长期以来使用的是普通滤纸、卫生纸、乃至黄草纸等代用品。这些纸张在协调种子发芽所需的水气条件方面存有不少缺陷,其质地、强度或吸水性等都达不到要求。为了填补国内这一空白,浙江农业大学种子科学中心和浙江民丰造纸厂造纸研究所自1987年开始进行种子发芽纸的研制。经过多次反复研制和测试,已研制成功一种种子发芽纸。它厚度适中,既可平垫于玻皿之中,又可用作发芽纸卷,且成本低于目前代用的普通滤纸。经数家种子部门试用,反应良好。此将发芽纸研制过程中生物学适用性测试的部分内容报告如下。     

包装对龙眼果实贮藏期间果皮失水褐变和细胞超微结构的影响

研究了(10±1)℃和50%相对湿度贮藏条件下无包装和0.015 mm厚的聚乙烯薄膜袋密封包装的“福眼”龙眼果实果皮失水、果皮褐变和细胞超微结构变化。结果表明,无包装的龙眼果实采后极易失水导致果皮迅速褐变,且褐变随贮藏时间的延长和果皮失水率的增加而升高,果皮褐变指数与果皮失水率呈极显著正相关(P<0.01)。在龙眼果皮失水褐变过程中,果皮细胞的细胞器和膜系统的完整性受到严重的破坏。而聚乙烯薄膜袋密封包装则显著减少了果皮失水和抑制果皮褐变,并保持较好的果皮细胞的细胞器和膜系统的完整性。据此认为,聚乙烯薄膜袋密封包装抑制龙眼果实失水果皮褐变与其维持细胞器和细胞膜的完整性有联系。     

Effects of solvent polarity and acidity on the extraction efficiency of isoflavones from soybeans (Glycine max)

Soy isoflavones have been correlated with beneficial health effects. The predominant chemical forms of isoflavones present may affect their biological activities. Choosing the solvent system that can accurately quantify the amounts of individual isoflavones present in these products is paramount. Our objectives were to compare frequently used solvent systems and to evaluate the effects of polarity and acidity on the recovery of isoflavones from soybeans. Isoflavones were extracted from pulverized Manokin soybeans using six solvent systems, which are the combinations of three polarity levels (83% acetonitrile, 80% methanol, and 58% acetonitrile) and two acidity levels (nonacidified and acidified). The pulverized soybean was stirred for 2 h in each solvent system before filtration and concentration using rotary evaporation. The extract was resuspended in 16% acetonitrile and analyzed by high-performance liquid chromatography. Recoveries of pure standards were evaluated with all solvent systems. Solvents with a higher polarity extracted a significantly higher amount of total isoflavones. For individual isoflavones, 58% acetonitrile (highest polarity) extracted either the highest amounts or no less than other solvents, while 83% acetonitrile (lowest polarity) extracted either the lowest amounts or no more than other solvents except for the aglycone form. Acidification significantly reduced the recovery of the malonylglucoside form and the total isoflavones. The recovery study revealed that acidification favored the chemical transformations of isoflavones during the extraction. Among the six solvent systems examined, 58% acetonitrile aqueous solution without acid was the best for extraction of isoflavones from soybeans.     

不同孔径泡沫铜填充对平板微热管传热特性的影响

为提升平板微热管传热能力,该研究以毛细力为出发点,将丝网芯-泡沫铜置于平板微热管中每一独立微细热管内部,使其与微槽芯组成复合吸液芯。通过调节平板微热管蒸发段加热功率的大小,研究反重力（倾角,即平板微热管与水平面之间的夹角小于0°）、微重力（倾角等于0°）及重力（倾角大于0°）工况下的传热特性及不同孔径泡沫铜对传热性能的影响。结果表明：反重力条件下,当倾角小于-10°时,平板微热管性能明显恶化,复合吸液芯对平板微热管传热无强化作用;添加孔径分别为0.2、0.5和0.8 mm泡沫铜的平板微热管在微重力或重力作用下传热性能明显强化,最小热阻分别为0.13、0.17和0.13 K/W;有效导热系数增加率分别为3.57、2.43和3.54。研究结果可为平板微热管强化传热提供数据参考,拓展其在热控领域中的应用范围。     

滇西泥石流综合防治工程调查

调查了滇西泥石流综合防治工程的现状,指出了滇西泥石流综合防治工程中存在的主要问题.在此基础上,具针对性地提出今后滇西泥石流综合防治工程应引起足够重视和有待加强的工作环节.     

Rapid isolation and identification of active antioxidant ingredients from Gongju using HPLC-DAD-ESI-MS(n) and postcolumn derivatization

Flos Chrysanthemi (Gongju, GJ) is used to prepare a herbal tea that is commonly consumed as a health beverage in Asia and is believed to contain abundant beneficial antioxidants. To rapidly identify the chemical constituents and to obtain the profile related to antioxidant activity, an online analytical method combining high-performance liquid chromatography-diode-array detector-electrospray ionization-ion-trap time-of-flight mass spectrometry (HPLC-DAD-ESI-IT-TOF-MS(n)) and postcolumn derivatization (PCD) has been applied for a precise and thorough identification of the chemical constituents. Meanwhile, the antioxidant profile has also been characterized by directly measuring the scavenging activity of each compound for the free radical produced by DPPH. As a result, 13 compounds have been identified in GJ, 7 of which account for its antioxidant activity. The established LC-MS(n)-PCD system has proved to offer a useful strategy for correlating the chemical profile with the bioactivities of the components without their isolation and purification, and may be used for multicomponent analysis of active substances in other foods and herbs.     

Determination of main categories of components in corn steep liquor by near-infrared spectroscopy and partial least-squares regression

Corn steep liquor (CSL) is an important raw material that has a high nutritional value and serves as a nitrogen source. This study aimed to develop a fast, versatile, cheap, and environmentally safe analytical method of quantifying the total acidity (TA) of CSL as well as its contents of dry matter (DM), total sugars (TS), total reducing sugars (TRS), total free amino acids (TFAA), total nitrogen (TN), and total sulfite (TSu). The near-infrared (NIR) spectroscopy measurements of 66 samples (22 batches) of CSL were analyzed by partial least-squares regression using several spectral preprocessing methods. Multivariate models developed in the NIR area showed good predictive abilities for DM, TA, TS, TRS, TFAA, TN, and TSu determination. These results confirm the feasibility of the multivariate spectroscopic approach as a replacement for expensive and time-consuming conventional chemical methods. Thus, a convenient and feasible method for the quality control of fermentation raw materials for food additives and fine chemicals, especially in CSL, is established.     

宁洱县典型烟田土壤系统分类研究

我国土壤系统分类现处于基层单元土族和土系建设迅速发展阶段,宁洱县是云南普洱市烤烟主要种植区之一,本文在宁洱县发生分类的水稻土和黄壤烟田上共选择了5个典型土壤剖面,通过形态观察和分层采样测试,研究了其在系统分类中的归属。研究结果：（1）5个典型剖面分别隶属于人为土、淋溶土、富铁土3个土纲、3个亚纲、3个土类、3个亚类、4个土族和5个土系;（2）就植烟适应性而言,5个土系的总体优势是土壤质地偏黏,有利于保水保肥,但土壤通透性略差,地形均为坡地,旱地烟田易发生水土流失。属于水耕人为土土纲的土系（水田）有机碳和有效磷养分含量较高,属于淋溶土、富铁土纲的土系（旱地）养分含量低,需要注意适当增施肥料和实施秸秆还田。     

基于灰色预测模型的温室温湿度系统建模与控制

温室温湿度系统是一个典型的混杂系统(hybrid system,HS),系统的输入包括环境调控设备的开关状态以及可测不可控的外界环境因子扰动输入,包括太阳辐射、室外温度、室外湿度、风速、风向等。针对温室温湿度系统的这种混杂特性,该文提出一种基于切换系统的温室温湿度系统建模与预测控制方法。首先,分别在天窗开启与关闭状态下采用遗忘因子递推最小二乘法(forgetting factor recursive least squares,FFRLS)辨识模型参数,得到系统的2个子系统模型。采用灰色预测GM(1,1)模型预测温室温室度系统中可测不可控的扰动输入。然后,将系统预测控制问题描述为混合整数二次规划问题(mixed integer quadratic problem,MIQP),并通过分支定界法求解。分析了系统在有限时间内的稳定性(finite time stable,FTS)。最后进行了仿真研究,仿真结果表明该文中提出的建模和控制方法是有效的。