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1.
本文介绍一种新研制出的挖掘机特性测试仪。仪器应用微机技术、自动采集挖掘机特性的电压和电流数据、可在通用示波器上显示或X—y记录仪绘出挖掘机特性曲线。输入标准特性参数后,自动计算并打印出丰满系数,电流和电压测试数据。采样速度为2160点/秒,精度为±1%,量程满足目前使用的4~23m~3电铲.仪器工作可靠,操作维护方便,为挖掘机的调试提供了一个先进的工具。 相似文献
2.
品性教育与人的全面发展 总被引:1,自引:1,他引:0
张敏 《信阳农业高等专科学校学报》2007,17(1):47-49
“品性”即道德,品性教育既是个人要求,也是社会责任,其目的在于促进人的全面发展。社会主义的品性教育应在吸收古今中外优秀的品性教育的经验基础上,坚持以马克思主义的人的全面发展观为指导,明确品性教育在人的全面发展中的地位与作用,努力探索一条有中国特色的社会主义品性教育之路。 相似文献
3.
可视化编程技术在发动机外特性曲线绘制中的应用 总被引:1,自引:0,他引:1
通过对汽车发动机外特性的理论分析,在处理汽车发动机外特性曲线时,建立了一种适合处理发动机外特性曲线的三次样条函数拟合的数学模型,在C Builder可视化开发平台上,编制了汽车发动机外特性曲线绘制程序.利用三次样条函数插值法对实验数据进行拟合,实现了发动机外特性曲线绘制的自动化. 相似文献
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RAPD标记在合浦珠母贝家系F1代的分离方式 总被引:6,自引:2,他引:6
对RAPD标记在合浦珠母贝F1代全同胞家系共27个样品中的分离方式进行了研究。从21条RAPD随机引物中筛选了8条引物用于扩增分析,结果共扩增出49个位点,其中正常位点47个(95.9%),异常位点2个(4.1%),即子代有扩增带而双亲无。47个正常位点中3个位点在F1中不分离(6.4%),44个位点发生分离(93.6%,即多态位点)。卡方检验表明,44个分离位点中32个符合孟德尔分离规律(72.7%),12个位点发生偏分离(27.3%)。符合孟德尔分离位点中按11分离位点占43.8%,31分离位点占56.2%,其中,父本特有标记、母本特有标记和双亲共有标记分别占28.2%,15.6%和56.2%,父本特有标记略多于母本特有标记。根据“双假测交”理论,11分离位点是构建F1代家系的作图位点。较高的11分离位点表明,利用RAPD标记构建合浦珠母贝遗传连锁图谱是可行的。 相似文献
8.
微生物燃料电池(microbial full cell,MFC)是利用微生物作为生物催化剂将碳水化合物转化为电能的装置。针对MFC输出电压低、功率小、内阻大的特点,该文研制了一种具有最大功率点跟踪(maximum power point tracking,MPPT)功能的能量收集电路和两级升压电路;基于MSP430和CC2500芯片设计了环境温度传感系统。测试结果表明,MFC的输出电压维持在316~390 mV范围内,实现了最大输出功率的跟踪,MPPT电路和升压电路分别输出1.1和3.5 V电压;无线温度传感器以每13ms的周期将环境温度无线传输到远程终端,验证了环境温度传感系统在最大功率点处对无线传感器网络节点供电工作的可行性,可为实现MFC主动式能量收集提供参考。 相似文献
9.
基于直流电机与全液压转向器直联的自动转向系统研究 总被引:3,自引:0,他引:3
针对农机装备电控液压自动转向系统生产成本高及电动方向盘自动转向系统中控制力矩小、存在自由行程的问题,设计了基于直流电机与全液压转向器直联的自动转向机构及其电控系统,该系统主要包括自动转向执行机构、自动转向控制器和液压转向机构等。自动转向执行机构与原车液压转向机构连接实现自动转向功能,考虑了底盘阿克曼角的自动转向控制器实现车轮转向的精确控制,通过在转向驱动电机输出轴安装电磁离合器和转向柱扭矩传感器实现人工驾驶模式和自动驾驶模式的自动切换。试验结果表明,车轮转角响应平均稳态误差小于0.1°,最大稳态误差为0.158°,±20°阶跃信号最快响应时间达1.2 s,超调量小于1%,可以满足对各种轮式农机的自动导航辅助驾驶转向系统性能的要求。 相似文献
10.
Deficit irrigation based on drought tolerance and root signalling in potatoes and tomatoes 总被引:1,自引:0,他引:1
Christian R. Jensen Adriano Battilani Georgios Psarras Franciszek Janowiak Zorica Jovanovic Xuebin Qi Sven-Erik Jacobsen 《Agricultural Water Management》2010,98(3):403-384
Agriculture is a big consumer of fresh water in competition with other sectors of the society. Within the EU-project SAFIR new water-saving irrigation strategies were developed based on pot, semi-field and field experiments with potatoes (Solanum tuberosum L.), fresh tomatoes (Lycopersicon esculentum Mill.) and processing tomatoes as model plants. From the pot and semi-field experiments an ABA production model was developed for potatoes to optimize the ABA signalling; this was obtained by modelling the optimal level of soil drying for ABA production before re-irrigation in a crop growth model. The field irrigation guidelines were developed under temperate (Denmark), Mediterranean (Greece, Italy) and continental (Serbia, China) climatic conditions during summer. The field investigations on processing tomatoes were undertaken only in the Po valley (North Italy) on fine, textured soil. The investigations from several studies showed that gradual soil drying imposed by deficit irrigation (DI) or partial root zone drying irrigation (PRD) induced hydraulic and chemical signals from the root system resulting in partial stomatal closure, an increase in photosynthetic water use efficiency, and a slight reduction in top vegetative growth. Further PRD increased N-mineralization significantly beyond that from DI, causing a stay-green effect late in the growing season. In field potato and tomato experiments the water-saving irrigation strategies DI and PRD were able to save about 20-30% of the water used in fully irrigated plants. PRD increased marketable yield in potatoes significantly by 15% due to improved tuber size distribution. PRD increased antioxidant content significantly by approximately 10% in both potatoes and fresh tomatoes. Under a high temperature regime, full irrigation (FI) should be undertaken, as was clear from field observations in tomatoes. For tomatoes full irrigation should be undertaken for cooling effects when the night/day average temperature >26.5 °C or when air temperature >40 °C to avoid flower-dropping. The temperature threshold for potatoes is not clear. From three-year field drip irrigation experiments we found that under the establishment phase, both potatoes and tomatoes should be fully irrigated; however, during the later phases deficit irrigation might be applied as outlined below without causing significant yield reduction:
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- Potatoes
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- After the end of tuber initiation, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.
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- Fresh tomatoes
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- From the moment the 1st truce is developed, DI is applied at 85-80% of FI for two weeks. In the middle period, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.
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- Processing tomatoes
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- From transplanting to fruit setting at 4th-5th cluster, the PRD and DI threshold for re-irrigation is when the plant-available soil water content (ASWC) equals 0.7 (soil water potential, Ψsoil = −90 kPa). During the late fruit development/ripening stage, 10% of red fruits, the threshold for re-irrigation for DI is when ASWC = 0.5 (Ψsoil = −185 kPa) and for PRD when ASWC (dry side) = 0.4 (Ψsoil, dry side = −270 kPa).