农业机器人轨迹优化自动控制研究——基于BP神经网络与计算力矩

以农业机器人精密轨迹优化自动控制为目标,在优化算法中引入BP神经网络与计算力矩法结合的自动控制器,旨在减少作业过程中的运动误差,提高其工作效率。首先,建立农业机器人数学模型,分析其运动学和动力学原理;然后,设计了农业机器人运动控制系统,引入BP神经网络对不确定动力学因素进行判断,并提出解决该因素的自适应学习法;最后,对该系统运用Mat Lab进行了仿真。试验表明:以BP神经网络与计算力矩法结合的自动控制器可以有效优化机器人运动路径,提高机器人整体作业效率,系统运行稳定、可靠性强,且对外部环境的干扰因素具有较强的自适应学习能力。     

European eel distribution and body condition in a river floodplain: effect of longitudinal and lateral connectivity

Abstract – We studied eel population characteristics (size classes, densities and body condition) in the lower Loire River floodplain (France) to evaluate the effects of longitudinal and lateral gradients. A total of 36 sites were electrofished in June 2005. The sites were grouped first into three river segments according to the distance inland corresponding to a longitudinal gradient and secondly into three lateral connectivity categories. Results indicate that small eels, especially those ≤300 mm, were very abundant downstream but density rapidly decreased upstream. In addition, eels ≤150 mm tended to be most abundant in connected waterbodies. Conversely, the distribution of larger eels was quite uniform across both dimensions. Eel condition decreased upstream. In parallel, in downstream river segment, eels had a lower condition in disconnected waterbodies than in connected ones. Eel specialists still have only a longitudinal perception of eel habitat. Our results suggest that lateral gradients should be also taken into consideration.     

内燃机空气滤清器试验台的研究

空气滤清器的性能优劣对发动机的性能有着重要的影响,为此建立内燃机空气滤清器试验台有着至关重要的作用.根据待测的空气滤清器的主要性能指标确定了空气滤清器试验台的基本配置及功用,并在此基础上以虚拟仪器技术作为控制核心初步构建了用以检测空气滤清器性能的试验系统.     

Association of brook trout and Oncorhynchus spp. with large wood jams in a Lake Superior tributary in a northern old‐growth watershed

Wood in streams functions as fish habitat, but relationships between fish abundance (or size) and large wood in streams are not consistent. One possible reason for variable relationships between fish and wood in streams is that the association of fish with wood habitat may depend on ecological context such as large‐scale geomorphology. We studied the relationship between salmonid assemblages and large wood jams (LWJ) in four settings that differed geomorphically at the scale of the stream corridor along a tributary to Lake Superior in old‐growth conifer–hardwood forest in northern Michigan. The focal fish species of this study were brook trout (Salvelinus fontinalis), which were wild in the stream. Relocation efforts for coaster brook trout (an adfluvial life history variant of brook trout) were ongoing in the study stream. We measured fish abundance and length in pairs of pools of similar size and substrate, but varying in the presence of LWJ; this allowed us to evaluate associations of fish simply with the presence of LWJ rather than with other channel or flow‐shaping functions of LWJ. The length of Oncorhynchus spp. and young introduced brook trout was not strongly correlated with LWJ presence; however, the presence of LWJ in pools was positively correlated with larger wild brook trout. We also found that the correspondence of LWJ with the abundance of salmonids appears to be moderated by the presence of alternative habitat in this relatively natural, old‐growth forest stream.     

Hydrolab DS5X水质多功能监测仪器的验收评价

对Hydrolab DS5X水质多功能监测仪器对浊度、pH、溶解氧、电导率、叶绿素a、蓝绿藻探头的验收评价方法进行了摸索,对有推荐标准的测量参数按推荐标准进行了试验验收评价,对没有相关标准的测量参数从理论和日常使用角度给出了可靠的参考验收方法,结果表明,这种方法是可行的。     

基于虚拟仪器的湿增压实验台测控系统研究

本文以湿增压动力装置实验台为物理模型，为进行相关实验完成了速度、流量、扭矩等重要参数的测量，并以N16221硬件为基础，基于虚拟仪器平台LabVIEW研制了实验台的测试软件。新设计的测试系统是基于虚拟仪器平台的模块化系统，使得研究人员的大部分精力集中于所要实现的功能上，而不是以往繁琐的算法和重复的编程上，参数易于修改，缩短了系统开发的周期，能满足实验需求。     

华南地区高大平房仓综合控温模式试验

根据华南地区生态条件,通过高温期间开展空调调节仓温等综合控温措施,基本实现了低温、低药量保粮,延缓了储粮品质劣变并抑制了虫霉活动。     

我国精细农业的应用研究

生物遗传育种技术的进步以及化肥、农药的使用,推动了世界农业的发展。但这种农业增长模式也带来了水土流失、生态环境恶化、生物多样性遭到破坏等诸多问题。在解决这些问题的进程中,逐渐形成了精细农业的理论体系。对精细农业技术思想、技术体系、技术应用的发展情况进行了研究,并结合我国具体情况,分析了精细农业在我国的应用前景。     

T-shaped malformation of the ventral colon in a Thoroughbred filly with colic

A 4-month-old Thoroughbred filly presented for abdominal pain was diagnosed with a T-shaped malformation of the ventral colon at exploratory laparotomy. Following resection and anastomosis of the large colon, no further episodes of abdominal pain occurred during a 12-month follow-up. Acute dehiscence of the linea alba occurred as a complication of the initial laparotomy, but was successfully managed following additional surgical repair. T-shaped malformation of the ventral colon has not previously been reported and is considered a congenital malformation of mesocolon formation.     

新疆地区大中型棉花芽种生产设备发展探析

目前国内棉花芽种生产基本以人工浸种催芽为主,存在受热、受氧不均等问题,难以达到理想的工艺技术要求。介绍了大中型棉花芽种生产设备的技术特点和优势,包括质量高、效率高、机械化程度高和成本低等,并对其应用前景进行了展望。