牧草切根机工作原理的分析与研究

论文作者根据研发要求,设计制造出一种牧草切根机具。该切根机具在草地高板结的情况下可以顺利入土切根。该论文着重对曲柄摇杆的运动以及直切刀的速度与受力进行分析,为设计牧草切根机提供依据。     

Analysis and control on shift quality of dual-clutch transmission

At present, euqi distance circle model is generally used for directly fitting acceleration peak attenuation. Epicenter distance or focal distance is the only coordinate statistical parameter of seismic station. For large earthquake with a long fault, the iso seismical curve of euqi distance exists serious deviation from realistic iso seismal curve. Six area model was addressed to correct the deviation. With the model, seismic station was divided into six areas by two cut lines of coincided with fault and four cut lines perpendicular to fault. The acceleration peak attenuation curve along cut lines was fitted to analyse the relationship between attenuation curve and area seismic station. Take Wenchuan earthquake for an instance, the accuracy of the model is much higher than that of euqi distance circle model and a little higher than that of four area elliptical model. And the model is more accurate than four area elliptical model in reflecting hanging and foot wall effect and direction effect.     

模拟3自由度振动条件下水果运输振动加速度传递率及损伤研究

为探寻水果卡车运输的振动及损伤，通过模拟3自由度振动试验，研究了梨塑料箱盛装时包装箱在各方向振动的加速度传递率，分析了振动频率对梨损伤的影响，探讨了梨在一定频率下振动至失去商品性时的振动次数与振动积累加速度的关系。试验结果表明，在一定振动频率范围内，越是上层塑料箱，其在各方向振动的加速度传递率越大，顶层塑料箱在左右、前后方向振动的加速度传递率远大于上下方向的；在相同加速度条件下，振动频率越小梨越容易产生损伤；在确定的振动频率下，梨振动至失去商品性时的振动次数N，与振动积累加速度g₀存     

Behavioural characteristics of loggerhead turtles (Caretta caretta) in a submerged bag net of a setnet observed in a bycatch simulation and the development of a turtle releasing device

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适应条件对鱼类续航游泳能力的影响

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转动副间隙对曲柄摇杆式分插机构性能的影响分析与试验

为了研究转动副间隙对曲柄摇杆式分插机构的影响,该文基于动力学理论及Lankarani-Nikravesh接触力模型,建立了含转动副间隙的曲柄摇杆式分插机构的动力学模型,并通过四阶龙格库塔法求解动力学模型。通过MATLAB仿真分析了转动副间隙对秧针尖的轨迹、速度、加速度和取秧位置的影响以及不同间隙大小和不同转动副含间隙对秧针尖加速度的影响。仿真分析结果表明,转动副间隙对秧针尖轨迹、速度和取秧位置的影响较小,对加速度的影响较大;随着转动副间隙的增大,分插机构取秧位置的偏离会增大,秧针尖的加速度的幅值和波动幅度会增大;在分析的3个转动副中,曲柄与连杆之间的转动副含间隙对秧针尖加速度的影响最大。通过试验与仿真对比得到基于Lankarani-Nikravesh接触力模型比基于连续接触模型更适用于含转动副间隙机构的分析。试验结果验证了基于Lankarani-Nikravesh接触力模型的仿真分析的正确性。研究结果为分插机构的结构优化设计和精度分配提供了参考。     

Vibration analysis during grass harvesting according to ISO vibration standards

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水平与竖向加速度-时程曲线叠加效应下边坡永久位移计算的极限上限分析

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