马铃薯曲面式播种开沟器仿生设计与试验

针对马铃薯播种开沟器高速作业条件下作业阻力大、回土深度浅、干湿土易混合等问题,基于黄鳍金枪鱼下颚流线型曲线,采用水平直元线法将原有曲线重构为三维曲面,设计一种仿黄鳍金枪鱼下颚曲线的曲面式开沟器.根据马铃薯种植深度的农艺要求,当最大作业深度为150 mm时,采用滑切原理确定了最大刃口角为132°,元线角为27 °.为探究...     

Predation risk allocation or direct vigilance response in the predator interaction between perch (Perca fluviatilis L.) and pike (Esox lucius L.)?

Abstract –  Predation risk allocation hypothesis predicts that a prey's response to predator depends on prey's previous experience on predator. Here we tested whether the group of three perch respond differentially to pike, predator of perch, depending on the timing of high constant (HC) and high unpredictable (HU) risk periods within low constant risk periods in short-term (10 h) experiments, and whether the response is stronger during a HU risk period than during a HC risk period. Perch clearly erected the dorsal fin in response to predation risk treatments (pike odour only, odour and visible pike). Decrease in activity and increase in shoaling behaviour were observed mainly during high risk periods. However, the perch's responses to pike did not differ statistically between periods of various levels of predation risk or depending on the timing of high risk situations within constant low risk periods, and thus, suggesting that perch respond mainly to changes in the current predation risk.     

仿生木材结构穿孔纤维板吸声性能

以中密度纤维板为基材,通过设计穿孔结构及打孔方式,达到拓宽木质穿孔板吸声频带和提高声学性能的目的.利用分层加工工艺制备了带侧孔结构的穿孔纤维板,采用阻抗管传递函数法对穿孔纤维板吸声性能进行了测试.通过正交试验方法,研究了主孔直径、穿孔率、倾斜角度对穿孔纤维板吸声性能的影响,并获得了较优的制备工艺,随后利用控制变量法研究...     

3%高渗苯氧威防治芦毒蛾幼虫的试验

采用3%高渗苯氧威超低量喷雾防治2~4龄芦毒蛾幼虫,7 d死亡率为79.1%~100%,平均防治效果88.9%,11 d后达到96.3%。田间观察没有发现鱼类死亡现象,对环境安全。     

Electrophysiological and behavioural responses of Pityophthorus pubescens (Coleoptera: Scolytinae) to (E,E)‐α‐farnesene, (R)‐(+)‐limonene and (S)‐(−)‐verbenone in Pinus radiata (Pinaceae) stands in northern Spain

BACKGROUND: Some twig beetles in the genus Pityophthorus (Coleoptera: Scolytinae) may vector pitch canker disease Fusarium circinatum (Niremberg & O'Donnell) of Pinus spp. (Pinaceae). Because Pityophthorus pubescens (Marsh.) has been found to be associated with F. circinatum in the Basque Country (northern Spain), various experiments were conducted to assess the beetle's behavioural responses to (E, E)‐α‐farnesene, (R)‐(+)‐limonene and (S)‐(?)‐verbenone to develop a potential inhibitor to host attraction. These experiments comprise electroantennographic and double‐choice olfactometer tests, as well as field assays in Pinus radiata D. Don stands. RESULTS: Both sexes of P. pubescens showed similar electroantennographic responses to different doses (from 1 ng to 1 µg in decadic steps) of each individual compound, with depolarisations to (S)‐(‐)‐verbenone (100 ng) being similar to those of the aggregation pheromone (+)‐trans‐pityol. In olfactometer assays, both sexes were significantly attracted to (+)‐trans‐pityol, but the attraction was reduced when increasing amounts of the chemicals were added to the pheromone. Particularly relevant was the repellent effect induced by (S)‐(?)‐verbenone at 1 ng dose and higher. In the field, (E, E)‐α‐farnesene, (R)‐(+)‐limonene and (S)‐(?)‐verbenone reduced significantly the number of beetles attracted to (+)‐trans‐pityol and racemic trans‐pityol, with (S)‐(?)‐verbenone being the most effective. CONCLUSIONS: (S)‐(?)‐Verbenone showed an interesting potential for use in the protection of P. radiata stands. A potentially effective strategy, which could be implemented in further, more in‐depth studies, could involve the use of this semiochemical as repellent and (+)‐trans‐pityol‐baited traps as attractant in a ‘push‐pull’ strategy. Copyright © 2012 Society of Chemical Industry     

青贮玉米切叶蚁上颚仿生粉碎刀片设计与试验

针对青贮玉米收获机粉碎刀片锋利度差、滑切性能弱等问题,该研究以切叶蚁上颚为设计原型,采用逆向工程技术提取并拟合其上颚滑切曲线,并依据该曲线设计一种仿生刃口曲线。应用EDEM构建秸秆离散元模型进行仿真切割试验,对比仿生刀片、斜刃刀片、直刃刀片在横切角90°、切削角0°参数条件下对秸秆的切割力变化过程,并利用高速摄像机记录台架对比试验中秸秆切割变形过程,结果表明秸秆切割变形过程可分为3个阶段：挤压阶段、切割阶段及贯穿阶段。仿真试验中仿生刀片对秸秆的最大切割力相较斜刃刀片、直刃刀片分别降低4.05%、6.09%,台架对比试验中仿生刀片对秸秆的最大切割力相较斜刃刀片、直刃刀片分别降低10.53%、12.82%,仿生刀片在提高秸秆切面平整度和降低秸秆最大切割力方面均具有明显优势。以刀型、横切角、切削角为试验因素,以秸秆的最大切割力为试验指标开展秸秆切割台架正交试验。试验结果表明：刀型、横切角对秸秆的最大切割力有极显著影响（P<0.01）,切削角对秸秆的最大切割力有显著影响（P<0.05）。使用较优参数组合进行验证试验的结果表明,横切角90°、切削角20°、仿生刀片对秸秆的最大切割力为...     

基于海鸥翼型的小型风力机叶片仿生设计与试验

针对现有小型风力发电机效率远低于理论值问题,对100 W水平轴风力机叶片进行仿生改进。采用Spalart-Allmaras模型分析不同攻角下海鸥翼型与标准翼型的气动特性;以标准100 W水平轴风力机叶片为原型,结合海鸥翼型、标准弦长和计算得出的安装角,设计得到仿海鸥翼型叶片;利用SST k-ω模型进行仿海鸥翼型叶片与标准叶片气动特性数值模拟;搭建室内风力机效率测试平台,进行仿海鸥翼型风力机与标准风力机效率对比试验。结果表明:海鸥翼型气动性能优良,最大升力系数是标准翼型的2.19倍,最大升阻比是标准翼型的1.34倍;仿海鸥翼型叶片与标准叶片相比,输出功率提高25.77%。该研究可为小型风力发电机的改进设计提供参考。     

吹扫式仿生嗅觉检测装置的设计与性能试验

为研究仿生嗅觉检测装置的检测性能,该文研制了一种吹扫式仿生嗅觉检测装置,选取传感器阵列灵敏度、响应时间和恢复时间作为装置性能指标,分析了传感器加热电压、待检气体湿度以及流量等控制参数对嗅觉检测性能的影响,并进一步验证优化控制参数的仿生嗅觉检测装置对气味检测的可行性和检测性能。试验结果表明:传感器阵列灵敏度随加热电压增大而增大,其响应和恢复时间随加热电压增大而减小,加热电压为5.0 V时,装置性能较佳,其传感器阵列灵敏度分布范围为2.260~4.823,响应和恢复时间分布范围分别为46~53 s、44~70 s;增加气体湿度会使传感器阵列灵敏度减小,同时也会延长响应和恢复时间,气体相对湿度为30%时,装置性能较佳;传感器阵列灵敏度随载气流量的增加先递增后减小,其响应和恢复时间随流量的增加先减小后递增,流量为100 m L/min时,装置性能较佳,其传感器阵列灵敏度分布范围为2.853~7.559,响应和恢复时间分布范围分别为35~50 s、30~50 s;在优化控制参数下,待检气体体积分数范围控制在0.002%~0.020%时,装置检测灵敏度较高,范围为3 577.1~6 700.7;线性特性和重复性较好,决定系数范围为0.901~0.997,变异系数范围为0.832%~9.696%,能满足仿生嗅觉气味检测的要求,可为后续开展仿生嗅觉的应用性研究提供数据参考与技术支撑。     

仿旗鱼头部曲线型开沟器设计与性能试验

为了减小播种开沟器的工作阻力,降低其对土壤的扰动,根据旗鱼头部的流线型曲线,建立了拟合曲线的数学模型,设计了仿旗鱼头部曲线型开沟器。为获得该开沟器工作时工作阻力及其对土壤扰动情况,进行离散元仿真和室内土槽试验。在前进速度为0.5 m/s时,分别以3种土壤含水率、3种开沟器开沟深度为因素进行仿真及室内试验。仿真结果:在含水率为12%±1%时,工作阻力、对土壤扰动宽度和回土深度随开沟深度的增加呈增加趋势;在开沟深度为60 mm时,工作阻力随含水率的增加而增加,但对土壤扰动宽度、回土深度影响不明显。工作阻力仿真与试验结果对比,两者变化趋势大致相同,相对误差在5.04%~27.08%之间。土壤扰动情况仿真与试验结果对比:回土深度的仿真与试验结果接近,而土壤扰动宽度的仿真与试验结果差别较大,可能是土壤颗粒粒径较大引起的,但变化趋势基本一致。由此说明了采用离散元法模拟开沟器的工作阻力及其对土壤扰动情况的可行性。该文可为开沟器的设计与优化提供参考。     

Pesticide Application Equipment

Abstract

Studies on the use of 22 chemical attractants for Glossina tachinoides were undertaken in Côte d'Ivoire following earlier work on G. m. morsitans and G. pallidipes in Zimbabwe. While catches of G. m. morsitans and G. pallidipes increased by several times when traps were baited with some of these substances, catches of G. tachinoides were only marginally increased. G. tachinoides is slightly attracted by octenol and acetone, alone or in combination, and its response to CO₂ is much weaker than that of the species tested in Zimbabwe. Phenol and indol mixtures both showed dose‐response relationships with catch. The indols were more potent in the lowest of the tested dosages (catch increase of 52%, P < 0001) whereas the phenols showed better attractiveness in their higher concentrations (catch increase of 42%, P < 0.05). Odour is probably less important in host finding for the riverine species G. tachinoides than it is for the savanna species studied in Zimbabwe.