壳聚糖对银杏叶水提液的絮凝工艺研究

采用天然高分子絮凝剂壳聚糖对银杏叶水提液进行絮凝提取,其目的是优化生产工艺,提高药液的澄清度和药液质量。实验利用光的吸收和散射定律,以絮凝率和总黄酮损失率为衡量指标,判断不同影响因素对絮凝效果的影响,并将其与醇沉工艺的提取方法进行比较。结果通过单因素实验先判断出有利于絮凝的趋势,之后又利用正交实验确定了絮凝的最佳工艺条件:絮凝剂质量浓度1.071 g/L,絮凝温度40℃,体系pH值4.9。并且得出壳聚糖对银杏叶水提液的絮凝工艺效果明显优于醇沉法。     

硫酸钡比浊法测定烟草中硫酸根(SO_4~(2-))离子

烟草中硫酸根离子的含量会影响其燃烧性、质量和吃味。为快速准确大量地测定烟草中硫酸根离子的含量,本文介绍了硫酸钡（BaSO4）比浊法测定烟草中硫酸根离子的方法。将烟草样品进行干灰化后制成待测液,定容至100 mL,在弱酸性条件下,SO4^2-和BaCl2作用生成溶解度很小的BaSO4白色沉淀。浓度在2～40mg/L范围内,其浑浊度与溶液中SO4^2-浓度成正比,通过比浊法即可测定溶液中的SO4^2-浓度。     

钢板弹簧力学特性的非线性有限元分析

利用非线性有限元方法,考虑钢板弹簧工作过程中的大变形、片间摩擦和接触等多种因素,在Ansys软件中建立钢板弹簧的力学模型,分析其力学特性。在不考虑摩擦和考虑摩擦两种情况下计算其刚度、应力分布、接触状态及接触压力,研究了摩擦情况对钢板弹簧力学性能的影响。通过考虑片间摩擦,钢板弹簧计算模型的精度得到了提高。     

基于光谱变换定量估算苹果叶片的等效水厚度

运用高光谱技术快速无损地估算了苹果叶片的等效水厚度(Equivalent Water Thickness, EWT),为苹果树的长势及干旱预警提供参考。以山东省烟台栖霞市红富士苹果树叶片为试验材料,在测定苹果叶片的光谱反射率和计算叶片EWT的基础上,分析了苹果叶片的EWT、原始光谱的反射率及其13种变换光谱反射率之间的相关性。筛选敏感波长后,建立了苹果叶片EWT的支持向量机定量的估算模型。13种光谱变换中,一阶导数(the First Derivative, FDR)、平方根的一阶导数(the First Derivative of the Square Root, FD(SqrtR))及倒数的对数的一阶导数(the First Derivative of the Logarithm of the Reciprocal, FD[Lg(1/R)])三种变换的相关性较好。确定了估测苹果叶片EWT的敏感波长。基于支持向量机回归分析方法,建立了定量估算叶片EWT的模型,验证集的决定系数R2达到了0.8147,相对分析误差(Relative Percent Deviation, RPD)达到了2.2671。结果表明,该模型具有较高的估测能力,支持向量机回归方法比较适于估算苹果叶片的EWT。该方法为利用高光谱技术定量估算苹果的生长状况提供了技术支撑。     

Aphid and Plant Volatiles Induce Oviposition in an Aphidophagous Hoverfly

Episyrphus balteatus DeGeer (Diptera, Syrphidae) is an abundant and efficient aphid-specific predator. We tested the electroantennographic (EAG) response of this syrphid fly to the common aphid alarm pheromone, (E)-β-farnesene (EβF), and to several plant volatiles, including terpenoids (mono- and sesquiterpenes) and green leaf volatiles (C6 and C9 alcohols and aldehydes). Monoterpenes evoked significant EAG responses, whereas sesquiterpenes were inactive, except for the aphid alarm pheromone (EβF). The most pronounced antennal responses were elicited by six and nine carbon green leaf alcohols and aldehydes [i.e., (Z)-3-hexenol, (E)-2-hexenol, (E)-2-hexenal, and hexanal]. To investigate the behavioral activity of some of these EAG-active compounds, E. balteatus females were exposed to R-(+)-limonene (monoterpene), (Z)-3-hexenol (green leaf alcohol), and EβF (sesquiterpene, common aphid alarm pheromone). A single E. balteatus gravid female was exposed for 10 min to an aphid-free Vicia faba plant that was co-located with a semiochemical dispenser. Without additional semiochemical, hoverfly females were not attracted to this plant, and no oviposition was observed. The monoterpene R-(+)-limonene did not affect the females’ foraging behavior, whereas (Z)-3-hexenol and EβF increased the time of flight and acceptance of the host plant. Moreover, these two chemicals induced oviposition on aphid-free plants, suggesting that selection of the oviposition site by predatory hoverflies relies on the perception of a volatile blend composed of prey pheromone and typical plant green leaf volatiles.     

Major Sex Pheromone Components of the Australian Gum Leaf Skeletonizer Uraba lugens: (10E,12Z)-Hexadecadien-1-yl Acetate and (10E,12Z)-Hexadecadien-1-ol

Two sex pheromone components of the gum leaf skeletonizer, Uraba lugens (Lepidoptera: Nolidae), recently established in New Zealand, were identified. Gas chromatography (GC) electroantennographic detection analyses of female pheromone gland extracts gave three compounds that consistently elicited antennal responses. Chemical analyses, using GC and GC-mass spectrometry, in conjunction with 4-methyl-1,2,4-triazoline-3,5-dione and dimethyldisulfide derivatizations, identified these compounds as (10E,12Z)-hexadecadien-1-yl acetate (E10,Z12-16:Ac), (10E,12Z)-hexadecadien-1-ol (E10,Z12-16:OH), and (Z)-11-hexadecen-1-yl acetate (Z11-16:Ac). A trapping trial in Queensland, Australia, in 2002, indicated that a blend of the two major components E10,Z12-16:Ac and E10,Z12-16:OH could attract gum leaf skeletonizer males. In the same trial, E10,Z12-16:Ac alone trapped large numbers of an unidentified nolid, Nola spp. Further trials in Auckland, New Zealand established that these two components were sufficient and necessary for trap catch of males; adding minor gland components, (10E,12E)-hexadecadien-1-yl acetate (E10,E12-16:Ac), Z11-16:Ac, or octadecan-1-ol (18:OH), to the two-component lure did not result in increased trap catches. Behavioral observations and gland analyses of the Auckland population revealed that female moths begin calling soon after emergence, with peak calling and pheromone production occurring 7 hr into the scotophase. Analysis of gland extract at two-hourly intervals during the first activity period showed that the ratio of E10,Z12-16:Ac to E10,Z12-16:OH (mean of 86: 14, respectively) and pheromone titer were fairly constant. No qualitative or quantitative differences in pheromone components were detected between gland extracts from Tasmanian univoltine and Auckland bivoltine populations of U. lugens.     

Oolong tea and LR‐White resin: a new method of plant sample preparation for transmission electron microscopy

Simplifying sample processing, shortening the sample preparation time, and adjusting procedures to suitable for new health and safety regulations, these issues are the current challenges which electron microscopic examinations need to face. In order to resolve these problems, new plant tissue sample processing protocols for transmission electron microscopy should be developed. In the present study, we chose the LR‐White resin‐assisted processing protocol for the ultrastructural observation of different types of plant tissues. Moreover, we explored Oolong tea extract (OTE) as a substitute for UA in staining ultrathin sections of plant samples. The results revealed that there was no significant difference between the OTE double staining method and the traditional double staining method. Furthermore, in some organelles, such as mitochondria in root cells of tomatoes and chloroplast in leaf cells of watermelons, the OTE double staining method achieved little better results than the traditional double staining method. Therefore, OTE demonstrated good potentials in replacing UA as a counterstain on ultrathin sections. In addition, sample preparation time was significantly shortened and simplified using LR‐White resin. This novel protocol reduced the time for preparing plant samples, and hazardous reagents in traditional method (acetone and UA) were also replaced by less toxic ones (ethanol and OTE).     

柿叶茶的保健功能及其制作工艺

柿树是河南省的传统优势树种,如何利用现有柿树资源制作柿叶茶,对进一步挖掘、提升柿树种植效益、增加柿农经济收入具有重要意义。本文介绍了柿叶保健茶的功能及其制作工艺。     

烟青虫和棉铃虫在陕西烟区的地理分布及其成因分析

调查表明，烟青虫Ｈｅｌｉｃｏｖｅｒｐａａｓｓｕｌｔａ（Ｇｕｅｎｅｅ）在陕西仅分布于关中和陕南；棉铃虫Ｈｅｌｉｃｏｖｅｒｐａａｒｍｉｇｅｒａ（Ｈｕｂｎｅｒ）虽在陕西各地烟田均有发生，但主要分布于陕北和关中。从地理上看，棉铃虫在陕北延安等地严重危害烤烟；在关中则主要危害烤烟留种田和晒烟留种株；在陕南发生极少，仅开花后在花上有少量幼虫。从生育期上看，在两种害虫混发的关中地区，团棵至旺长期主要是烟青虫，而棉铃虫仅在干旱的渭北旱塬上发生，开花后则逐渐过渡到棉铃虫为主，９月以后留种田发生的全为棉铃虫。推测棉铃虫起源于北方干旱地区，烟青虫则起源于湿润的东洋区。讨论了这两种夜蛾分布区差异以及造成中关烟田早、中晚期区系组成差异的原因。初步提出了烟青虫和棉铃虫在陕西当地蜜源植物间转移的可能规律．并提出了防治对策的建议。     

新型贝氏体板簧钢的组织及性能

针对汽车减重和环保问题,自行设计研制了车用新型贝氏体板簧钢,并对其组织和力学性能进行研究。结果表明,该钢经正火热处理即可得到无碳贝氏体组织;XRD检测表明,其物相组成以α相为主;该钢具有优良的综合力学性能和耐腐蚀性能,屈服强度近1200 MPa,抗拉强度达1400 MPa,常温下,冲击吸收能量达到73.2 J以上,强韧性配比优异。