深根茎中药材收获机夹持带转速自动控制系统

我国现有的深根茎中药材收获机械简易,工作效率低,作业质量差,成为中药材种植业发展的一个瓶颈。为此,以AT89 C52单片机为控制核心,以开关传感器为检测手段,结合自动控制原理设计了深根茎中药材收获机夹持带转速自动调节系统。该系统能使夹持带转速实时跟踪机器作业速度变化,从而大大提高了药材的收获效率,降低了药材损失率和破损率。室内土槽试验表明,此控制系统达到了预期设计要求。     

三阶开环控制系统根轨迹图形的研判

利用根轨迹极坐标方程对三阶系统根轨迹进行了研究，得出了三阶系统根轨迹的基本图形为双曲线的结论，并对图形的各种具体情况进行了进一步的讨论。     

后抛式免耕播种机碎秸装置离地高度自动控制系统研制

为了解决秸秆粉碎后抛式免耕播种机田间作业时,碎秸装置入土灭茬造成作业负载大、秸秆输送装置拥堵和卡滞的问题,该文研制了基于双扇形孔金属检测圆盘和接近开关的扭转变形采集装置,以有效监测驱动轴的转速和因扭矩负载变化引起的驱动轴错位角。设计了基于32位ARM CortexTM-M3核微处理器的碎秸装置离地高度自动控制系统,实时采集驱动轴转速和错位角,分析其变化趋势,辨别作业工况,输出相应电磁阀控制信号,驱动液压缸适时调整碎秸装置的离地高度,稳定作业负载。试验结果表明,在2 500 r/min的驱动轴额定转速下,碎秸装置离地高度的改变使作业负载变化时,自动控制系统使驱动轴的转速控制在2 448～2 632 r/min之间,驱动轴错位角的变化量为±0.002 4 rad,控制信号对错位角变化的响应延时为0.24 s。田间试验结果表明,利用碎秸装置离地高度自动控制系统后机具的通过性极大改善,堵塞现象消失,作业效率提高52.9%,碎秸作业后地表残茬高度降低43.4%。该设计利用驱动轴转速和错位角的变化趋势辨别作业工况,消除了机械结构参数和材质差异等因素对驱动轴错位角的影响,可为相关农机具扭矩负载定性监测提供借鉴。     

An evaluation of fresh gas flow rates for spontaneously breathing cats and small dogs on the Humphrey ADE semi‐closed breathing system

ObjectiveTo evaluate the fresh gas flow (FGF) rate requirements for the Humphrey ADE semi-closed breathing system in the Mapleson A mode; to determine the FGF at which rebreathing occurs, and compare the efficiency of this system to the Bain (Mapleson D) system in spontaneously breathing cats and small dogs.Study DesignProspective clinical study.AnimalsTwenty-five healthy (ASA score I or II) client-owned cats and dogs (mean ± SD age 4.7 ± 5.0 years, and body weight 5.64 ± 3.26 kg) undergoing elective surgery or minor procedures.MethodsAnaesthesia was maintained with isoflurane delivered via the Humphrey ADE system in the A mode using an oxygen FGF of 100 mL kg⁻¹ minute⁻¹. The FGF was then reduced incrementally by 5–10 mL kg⁻¹minute⁻¹ at approximately five-minute intervals, until rebreathing (inspired CO₂ >5 mmHg (0.7 kPa)) was observed, after which flow rates were increased. In six animals, once the minimum FGF at which rebreathing occurred was found, the breathing system was changed to the Bain, and the effects of this FGF delivery examined, before FGF was increased.ResultsRebreathing did not occur at the FGF recommended by the manufacturer for the ADE. The mean ± SD FGF that resulted in rebreathing was 60 ± 20 mL kg⁻¹minute⁻¹. The mean minimum FGF at which rebreathing did not occur with the ADE was 87 ± 39 mL kg⁻¹minute⁻¹. This FGF resulted in significant rebreathing (inspired CO₂ 8.8 ± 2.6 mmHg (1.2 ± 0.3 kPa)) on the Bain system.ConclusionsThe FGF rates recommended for the Humphrey ADE are adequate to prevent rebreathing in spontaneously breathing cats and dogs <15 kg.Clinical relevanceThe Humphrey ADE system used in the A mode is a more efficient alternative to the Bain system, for maintenance of gaseous anaesthesia in spontaneously breathing cats and small dogs.     

基于PLC的番茄收获机分离装置转速控制系统设计

4FZ-30型番茄收获机分离装置的液压马达转速在工作过程中受发动机转速以及负载等因素影响较大。为提高番茄收获机分离装置转速的控制精度,以PLC为核心设计了分离装置转速控制系统,给出了系统的硬件构成以及马达转速的采集、转速PID控制的程序流程图,并设计了触摸屏的人机操作界面。该系统有效地提高了对番茄收获机分离装置转速的控制精度。     

根癌农杆菌介导的‘魏可’葡萄遗传转化体系的优化

以‘魏可’葡萄离体叶片为外植体,利用植物表达载体上含有卡那霉素抗性基因(nptⅡ)的根癌农杆菌LBA4404(pCAMBIA2301)对影响‘魏可’葡萄遗传转化效率的因素进行系统研究。结果表明,最佳农杆菌介导‘魏可’葡萄遗传转化体系为农杆菌侵染4 min,共培养3 d,卡那霉素质量浓度5 mg·L-1,羧苄青霉素质量浓度200 mg·L-1。采用此体系对‘魏可’葡萄进行转化,共获得9株抗性苗。利用GUS组织化学染色、PCR扩增的方法检测,结果表明,有4株通过了PCR检测,1株通过了RT-PCR检测,初步证明nptⅡ基因已经整合进入‘魏可’葡萄基因组中。将PCR产物回收,经测序验证nptⅡ基因完全整合进入‘魏可’葡萄基因组中。对CK及经PCR检测呈阳性的株系进行卡那霉素抗性鉴定,发现PCR呈阳性的株系均比CK抗Kan的能力明显增强。     

小麦条锈病流行程度趋势预测专家系统雏型

本文运用知识工程语言 M·1构造了一个用于小麦条锈病流行程度趋势预测的专家系统雏型。专家的知识用产生式规则来表示。知识库中的知识规则可相对独立,便于知识库的扩充和完善。     

The effects of feeding frequency on waiting time,milking frequency,cubicle and feeding fence utilization for cows in an automatic milking system

Abstract

In this trial, the effects of the forage feeding frequency on the waiting time prior to milking and the cowshed facility utilization by cows milked in an automatic milking unit (AMU) were studied. The feeding frequency was increased from two times per day to six times per day. It was found that the average waiting time per visit for cows using the AMU was reduced from 755 s to 351 s when the feeding frequency was increased. The daily number of visits (milking visit, failed milking visit and not qualified visit) to the AMU was not affected by the change in feeding frequency. It was also found that increasing the feeding frequency had a positive effect on utilization of the cowshed facilities, such as the occupation of the feeding fence, and on the cowshed facilities in the waiting area (cubicles) of the AMU.     

广义系统能量有限的有限制调节器问题的探讨

讨论了广义系统能量有限的有限制调节器问题；通过对广义熵系统(相对不可测子空间)观测状态中的慢状态进行反馈，保证闭环系统正则，得到了在容许初值条件下该问题有解的充要条件。     

鸡蛋自动上料装置机构分析与试验

为了优化鸡蛋加工生产线吸盘自动上料装置的结构参数,并确定样机安装中关键零部件同步位置,对该装置的核心部分——吸盘摆臂组合机构进行了结构分析和运动仿真。结果表明:由曲柄摇杆、齿轮和同步带串联组合的吸盘摆臂组合机构自由度为1、曲柄整周转动、摇杆往复摆动60°、摆臂往复摆动180°;同步带角度补偿可以保证在摆臂180°摆动中,吸盘组件始终处于水平状态,保证鸡蛋水平搬运;摆臂末端运动参数(位移、速度、加速度)变化曲线显示,当摇杆摆动到2个极位146°和206°附近时,摆臂存在一段水平速度为零的垂直上下运动,分别对应曲柄84°~108°和252°~312°,以确保吸蛋和放蛋时吸盘垂直运动;为了保证该装置同步协调运动,样机安装时必须使曲柄在96°时,摇杆处在146°、摆臂处在174°位置。样机试验表明:理论分析和仿真结果与样机实测值一致性较好。