不同工艺聚乳酸膜用于加热卷烟的降温性能研究

为探究不同工艺对聚乳酸膜(PLA)作为加热卷烟降温段材料的降温性能影响,采用吹塑、拉伸与流延等成型工艺制备了3种PLA膜并加工成相应的基棒,并考察了3种膜的热物性参数（热扩散系数与导热系数等）及降温段基棒对模拟热气流的降温效果。结果表明,拉伸膜在3种PLA基棒中的降温效果最优,3种基棒降温性能的优劣主要与其在成型过程中的热历史与受力史导致的分子链取向与结晶度差异有关。因此,通过调整PLA膜成型工艺可以调控其降温性能,能够为加热卷烟降温材料的设计与加工提供有益指导。     

蚯蚓粪覆盖对土壤水分蒸发过程的影响

通过模拟试验研究蚯蚓粪覆盖对土壤水分蒸发过程的影响,以蚯蚓粪覆盖厚度和覆盖度为试验变量,试验处理设置如下:覆盖度90%时,4个处理分别为覆盖1 cm、2.5 cm、4 cm和裸土;覆盖厚度2 cm时,4个处理分别为覆盖度30%、60%、90%及裸土,均连续测定15 d的土壤日蒸发量和12 h的日变化量,以及蒸发前后蚯蚓粪和土壤的有机质含量。结果表明:在覆盖度一定的条件下,土壤蒸发量随蚯蚓粪覆盖厚度的增大而减少;当覆盖厚度一定时,覆盖度越大,对土壤蒸发的抑制作用越强,但覆盖度对土壤蒸发过程的影响小于覆盖厚度。因此,蚯蚓粪覆盖对土壤蒸发有一定的抑制作用,土壤蒸发量随着蚯蚓粪覆盖度和厚度的增加而减小。由于蚯蚓粪具有良好的保水性能,且能够有效增加土壤有机质含量,因而对提高土壤持水能力有促进作用。     

冬枣早期落叶病致病菌分离鉴定及防治药剂筛选试验

【目的】为了明确引起冬枣早期落叶病的致病菌并选择有效的药剂进行防治。【方法】采集具有典型症状的病害标样,室内分离纯化后选取5个代表菌株,对病原细菌形态、培养性状、染色反应、生理生化反应和致病性等性状进行测定,并与棉花角斑病菌和烟草野火病菌进行比较、同时室内测定了31种杀菌剂对冬枣早期落叶病病菌的皿内抑菌效果;【结果】结果表明,甘蓝黑腐黄单胞菌和洋葱假单胞菌均能引起冬枣早期落叶病,田间以甘蓝黑腐黄单胞菌侵染为主。硫酸链霉素、72％农用链霉素、新植霉素、50％代森锰锌等4种药剂防治效果最好,抑菌圈直径为j．8～4．8cm,押菌斑透明程度好。[结论]初步筛选出了4～6种抑菌效果较好的单剂,用于田间防治试验和防治示范推广。     

Analysis of elastohydrodynamic lubrication of steel planar wormgear drive

Based on study of elastohydrodynamic lubrication (EHD) and meshing theory of planar worm gear drive, EHD model for the drive is proposed. Minimum film thickness on the whole contact area is calculated. EHD status for the drive is analyzed. The distributions of film thickness show that, EHD status during entry engagement is better than that during exit engagement, and EHD status of worm addendum area is better than that of dedendum area. Influencing factors such as work conditions and optimized parameters along with their effects were analyzed. Theoretical analysis suggests that the optimizing pressure angle and increasing worm pitch diameter have influence on improving lubricant performance of the planar worm gear drive.     

豫南茶园尺蠖类害虫发生规律及防治

为害茶树尺蠖类害虫有10多种,其中茶尺蠖和茶银尺蠖是为害豫南茶园尺蠖类害虫的优势种,其一生经过卵、幼虫、蛹、成虫4种虫态,以其幼虫蚕食茶树嫩叶为害,危害发生期从4～11月中旬,严重影响茶叶产量和品质。为了有效控制其危害,总结出该类害虫防治措施。     

广西桑蚕原料茧解舒率与茧层丝胶初期溶解速度的关系探讨

本文通过对不同品种、不同庄口与季节原料茧茧层丝胶性能研究,结果表明广西的桑蚕原料茧,春茧和秋茧5min、10min两个处理水平的茧层丝胶初期溶解速度与蚕茧解舒率之间都存在着良好的正相关关系,茧层丝胶初期溶解速度越大,蚕茧的解舒率越大。庄口和季节是影响广西桑蚕原料茧茧层丝胶初期溶解速度的重要因素。而茧层丝胶初期溶解速度与蚕茧解舒率在品种水平上则没有相关关系,也就说明茧层丝胶初期溶解速度在品种间虽然有差异,但蚕品种并不是主要制约或影响蚕茧茧层丝胶初期溶解速度的直接因素。     

太湖重金属污染沉积物中的铁硫地球化学特征及其与相关重金属的关系

To understand the geochemical characteristics of iron and sulfur and the extent of iron-sulfide minerals influencing heavy metal behaviour in metal-polluted sediments of Talhu Lake, two sites, in Meiliang Bay （ML） and Wuli Lake （WL）, were selected to study the fractionation of iron, sulfur and related heavy metals. There were relatively high concentrations of Fe^2＋ and low concentrations of total S^2- in porewaters, indicating that conditions in these sediments favored iron reduction. The concentrations of acid volatile sulfides in sediments were 1.9-9.6 μmol g^-1 at ML and 1.0-11.7 μmool g^-1 at WL, both in the range of values detected in unpolluted lakes. Pyrite-S was 10.2-49.4 μmol g^-1 at ML and 10.3- 33.0 μmol g^-1 at WL, accounting for more than 69% of the reduced inorganic sulfur at both sites. The low degree of sulphidization （〈 14%） and pyritization （〈 10%） indicate that sulfate may be the limiting factor for pyrite formation. The extractability of Mn, Cu, Pb, Zn, Ni, and Cr in sediments all suggest that sulfides are not the major binding phase for these metals during early diagenesis. Sulfur may play a modest role in the geochemistry of iron and traced metals in the sediments.     

Analysis of fungal endophytes in Scottish Sitka spruce plantations shows extensive infections,novel host partners and gives insights into origins

This preliminary study identified the fungal endophytes of Sitka spruce (Picea sitchensis) in four Scottish plantations, analysed their recruitment possibilities and community structure across the sites, and identified the possible origins of the endophytes in this non‐native host. Although Sitka spruce is native to north‐western North America, it comprises a huge portion of Scottish forestry and is an economically vital timber tree. Needles from two age classes were collected and cultured for emerging endophyte isolates. Using a combination of morphological features and genetic sequencing of the nuclear ribosomal ITS regions of representative morphological types, 57 morphotypes were recorded which represented at least 15 different species, including a hypothesized sister species to the pathogen of Pseudotsuga menziesii in North America and Europe, Nothophaeocryptopus gaeumannii (previously P. gaeumannii) that was present at all sites tested. Diversity, recruitment, site, needle age and needle part effects are discussed. The phylogeny of Nothophaeocryptopus based on analysis of combined ITS and Tub2 sequence data is given in order to assess the relationship of the unknown endophyte to the Douglas fir pathogen N. gaeumannii.     

取食不同蔬菜的菜粉蝶幼虫对抑食肼的敏感性测定

叶片残留法测定结果表明,取食芥蓝（ＢｒａｓｓｉｃａａｌｂｏｇｌｏｇｒａＢａｉｌｅｙ）白菜（ＢｃｏｍｐｅｓｔｒｉｓＬ．ｓｓｐ．ｃｈｉｎｅｎｓｉｓ（Ｌ．）Ｍａｒｋｉｎｏｖａｒ．ｃｏｍｍｕｎｉｓＴｓｅｎｅｔＬｅｅ）,菜心（Ｂ．ｃａｍｐｅｓｔｒｉｓＬ．ｓｓｐ．ｃｈｉｎｅｎｓｉｓｕｔｉｌｉｓＴｓｅｎｅｔＬｅｅ）,萝卜（ＲａｐｈａｎｕｓｓａｔｉｕｍｖＬ．）的３,５龄菜粉蝶幼虫均对抑食腊的敏感性差异较大,ＬＣ５     

0.1%氧化苦参碱水剂防治菜青虫田间药效试验

田间试验结果表明:0.1%氧化苦参碱水剂80～200mL/667m2剂量,施药后3d防效达94.36～99.27%,药后7d其防效仍达99.08%以上,与对照药剂相比效果明显,适宜施药剂量为150mL/667m2。药后安全性调查表明该药剂对作物安全,适合“无公害”蔬菜生产。