红蓼提取物对13种农业害虫触杀活性的研究

关于红蓼提取物对农业害虫的触杀活性,国内外研究甚少。研究红蓼提取物对害虫的触杀活性,可为利用该植物研制新型植物源杀虫剂提供理论依据。本研究采用浸渍法测定了红蓼提取物对害虫的触杀活性,结果表明,红蓼种子乙酸乙酯萃取物对粘虫、菜粉蝶、棉铃虫、甘蓝夜蛾、甜菜夜蛾和小地老虎4~5龄幼虫具有很强的触杀活性,在16.80 g/L浓度下的校正死亡率在87.50%~100%;对小菜蛾3龄幼虫也具有很强的触杀活性,在21.00 g/L浓度下的校正死亡率为92.85%;秋季茎秆乙酸乙酯萃取物对菜粉蝶4龄幼虫和粘虫5龄幼虫具有很强和较强的触杀活性,在33.60 g/L浓度下的校正死亡率分别为100%和59.20%。盛花期茎秆石油醚粗提物对棉蚜具有较强的触杀活性,在0.27 g/L浓度下的校正死亡率为51.65%。盛花期花石油醚和甲醇粗提物对朱砂叶螨具有很强的触杀活性,在0.13和1.15 g/L浓度下的校正死亡率均高达100%。     

Effects of surfactants on primisulfuron activity in barnyardgrass (Echinochloa crus-galli [L.] Beauv.) and green foxtail (Setaria viridis [L.] Beauv.)

Laboratory and greenhouse studies were conducted to measure the contact angle of primisulfuron droplets with and without surfactants on the leaf surfaces of barnyardgrass and green foxtail, to determine the primisulfuron activity on these weed species, and to examine the spray deposit of primisulfuron with and without surfactants on the leaf surface of green foxtail using scanning electron microscopy. A non-ionic surfactant (NIS) and an organosilicone wetting agent (OWA) were used. The contact angles of 1 μL droplets were measured on the leaf surface using a goniometer. The activity of primisulfuron on barnyardgrass and green foxtail was assessed at 3 weeks after treatment based on visual injury and the fresh weight. The contact angles of the droplets of primisulfuron on the adaxial surface of the barnyardgrass and green foxtail leaves were 152° and 127°, respectively, when applied without surfactant. The addition of either surfactant markedly reduced the contact angle for both weed species, which was lowest when the OWA was added to primisulfuron. The percentage injury of barnyardgrass was very low, even at the higher rate of primisulfuron, regardless of the surfactant. Primisulfuron at 40 g ha⁻¹ controlled 43% of green foxtail without surfactant, which increased to 65% with the NIS and 83% with the OWA. Primisulfuron with a surfactant markedly reduced the fresh weight of green foxtail compared with primisulfuron applied alone, regardless of the primisulfuron rate and surfactant type. The scanning electron micrographs showed a uniform deposit of spray droplets, with close contact of the droplets to the leaf epicuticular surface in green foxtail in the presence of a surfactant compared with no surfactant. The enhanced primisulfuron activity on green foxtail with surfactants was related to the reduced contact angle and uniform deposition of the primisulfuron spray droplets on the leaf surface.     

16种植物乙醇提取物对桔全爪螨的生物活性测定

测定了16种植物乙醇提取物对桔全爪螨成螨的产卵忌避、驱避及毒杀生物活性。试验结果表明,海芋、山苍子及盐肤木茎叶的乙醇提取物有明显的产卵忌避作用,忌避率在96.43%以上;山苍子、枫香植物乙醇提取物对桔全爪螨成螨的驱避作用明显,驱避率在80%以上;山苍子、盐肤木茎叶、牡荆和幌伞枫提取物对桔全爪螨成螨的毒杀效果明显,在处理72h后,死亡率在92%以上。     

苯甲醛苯甲酰腙的合成及生物活性研究

以苯甲醛、苯甲酸甲酯、水合肼为原料,合成了苯甲醛苯甲酰腙。经元素分析、红外光谱对目标化合物进行了结构表征,并研究了苯甲醛苯甲酰腙对蓼蓝齿胫叶甲的生物活性。结果表明,苯甲醛苯甲酰腙对蓼蓝齿胫叶甲幼虫具有较强的触杀活性和胃毒活性,而拒食作用较弱。     

生物炭和乙醇改性生物炭对铜的吸附研究

为研究生物炭和乙醇改性生物炭的特性及其对铜的吸附能力,选取小麦秸秆为原料,在300、450、600℃条件下热解制备生物炭,用于研究乙醇改性生物炭的产油率、生物炭和乙醇改性生物炭的表面官能团变化、亲水性能及其对Cu~(2+)的吸附特性。结果表明:乙醇改性生物炭产油率随热解温度升高而增加。生物炭和乙醇改性生物炭不同温度接触角范围为122.6°~89.3°和96.0°~68.7°,乙醇改性生物炭亲水性明显高于未经改性生物炭。生物炭和改性生物炭对Cu~(2+)的吸附符合二级动力学模型,生物炭吸附速率常数达1.535 g·mg~(-1)·h~(-1),乙醇改性生物炭为1.073 g·mg~(-1)·h~(-1)。二者对Cu~(2+)的等温吸附过程符合Langmuir等温吸附模型,生物炭和乙醇改性生物炭最大吸附量分别为44.3 mg·g-1和41.7 mg·g-1,说明使用乙醇萃取生物炭生物质油后,仍能保持90%左右的Cu~(2+)吸附效率。     

管土接触作用下管道沉陷复杂应力分析

场地沉陷是导致埋地管道破坏的重要原因之一.应用管道与土体接触作用的半无限屈服理论,建立了沉陷作用下管土相互作用模型,以土壤和管道自重为载荷,计算了沉陷区长度、壁厚、内压、管径、管土摩擦因数、管道埋深等复杂因素作用下的管道应力,分析了其对管道Mises应力的影响规律,进而评估管道的安全性.算例分析结果表明,该方法能够较好模拟管道的破坏过程,可为沉陷区域埋地管道数值模拟提供理论依据.（表3,图7,参10）     

基于微观球体颗粒模型的土水特征曲线研究

When variations occur in the water content or dry bulk density of soil,the contact angle hysteresis will affect the soil-water characteristic curve(SWCC).The occurrence of the contact angle hysteresis can be divided into slipping and pinning.It is difficult to determine the effect of pinning existence on SWCC by tests.In this study,the effect of contact angle hysteresis on SWCC was analyzed either in the case of no variations in soil dry bulk density with changes in soil water content or no variations in soil water content with changes in soil dry bulk density.In both cases,soil particles were simplified to the spherical particle model.Based on the geometrically mechanic relationship between the particles and connecting liquid bridges,a physical model for predicting the SWCC was derived from the spherical particle model.Adjusting parameters made the model applicable to various soils,that is,the cohesive soil was considered as micron-sized spherical particles.Through the simulations on SWCC test data of sand,silt,clay,and swelling soil,it was confirmed that the physical model possessed good reliability and practicability.Finally,the analysis of rationality of contact angle was performed based on the basic assumptions of the model.     

微粗糙表面混合接触边界膜影响分析

研究了由微粗糙表面与光滑平面形成的混合接触承载性能.混合接触由固体-边界膜-固体三体接触和固体-流体固体三体接触组成.两表面相对滑动时表面间形成许多个微阶梯轴承.这些微阶梯轴承的承载量之和构成两接触表面承载量.微阶梯轴承的入口区为传统流体区域,出口区为边界膜区域.给出了微阶梯轴承承载能力分析方法,研究了边界膜对混合接触承载能力和接触性能的影响.     

机械弹性车轮提高轮胎耐磨性和抓地性分析

为提高轮胎接地性能,对新型机械弹性车轮垂直静态接地特性进行了研究。通过对车轮结构和承载方式进行分析,分别建立了基于Timoshenko圆形梁的车轮外圈弹性圆环模型和基于连续辐板的铰链组模型,并通过非线性有限元法和试验进行了验证。根据所建立的非线性有限元模型对机械弹性车轮和子午线充气轮胎的接地特性进行了对比研究,结果表明机械弹性车轮通过悬毂式承载控制车轮外圈变形,没有胎肩处的应力集中。在载荷为5 000 N时,机械弹性车轮和充气轮胎接地印迹中心0.14 m×0.265 m矩形区域内的接地压力偏度值分别为0.424和0.536 MPa。机械弹性车轮有效降低了接地压力偏度值,改善了轮胎接地的均匀性,提高了车轮耐磨损性能和抓地性能,研究为车轮性能优化提供了参考。     

具有塑性变形的转盘轴承有限元分析方法

为了计算考虑支撑结构柔度和材料塑性变形影响的大型重载转盘轴承内部载荷分布和接触应力,将内外圈滚道与滚动体接触等效成单向压缩弹簧,从而建立包括支撑结构在内的轴承整体简化有限元模型.等效弹簧系数由单个滚动体的载荷-弹塑性变形关系曲线确定,而单个滚动体的载荷-弹塑性变形关系应用有限元接触分析法求得.算例分析表明对于具有塑性变形的转盘轴承,接触变形、滚动体载荷分布、内外圈应力、接触应力等赫兹理论计算结果与有限元弹塑性分析法计算结果存在较大差异.因此,对于大型重载转盘轴承不适合采用赫兹理论进行分析计算.