单轴散生竹地下根茎并行模拟仿真研究

针对竹林地下根茎模拟仿真计算强度高、数据量大,在算法实现中采用基于单路处理器、串行计算的构架难以满足性能要求的问题,提出一种基于网络机群的多节点并行模拟仿真实现机制,构建了单轴散生竹地下根茎并行模拟仿真平台,主要由建模节点、任务管理节点、图形节点和网络交换机组成。以SimRoot模型为基础建立单轴散生竹地下根茎生长模型,通过实验观察获取几何构型参数及生长参数。采用功能分解法对根茎生长建模计算进行任务分割,建立了相应的任务调度管理模式,设计了多节点并行生长建模机制。以金竹为例开展多节点并行仿真实验,实验结果表明基于网络机群的多节点并行模拟仿真在降低内存消耗、缩短仿真时间方面效果明显,对于较大规模的散生竹林地下根茎模拟仿真具有较好的适应性。     

基于自适应神经模糊网络的果蔬抓取力控制

运用自适应神经模糊推理系统设计了农业机器人果蔬抓取力智能控制器。以当前抓取力和滑觉传感器信号的小波变换细节系数作为控制器的输入,末端执行器两指闭合距离作为控制器的输出。基于减法聚类建立模糊推理模型,通过调整聚类半径来优选模糊规则数。给出了训练样本数据集采集方法,并应用梯度下降与最小二乘混合训练算法辨识了控制器的前件参数和结论参数。对所设计的控制器进行了实验验证,结果表明该控制器能够适应果蔬质量、表面摩擦特性等方面的差异。抓取力超调量得到了限制,最大值小于0.8 N,可以避免给抓取对象造成机械损伤。     

大孔吸附树脂纯化生姜提取物中6-姜酚工艺优化

比较了6种大孔吸附树脂对6-姜酚的吸附和解吸性能,在静态吸附研究基础上筛选出效果较好的树脂进行动态试验,并通过HPLC-UV和GC-MS对纯化前、后的成分进行了定性和定量分析。结果表明:D101型大孔树脂更适合纯化姜油树脂中的6-姜酚,其纯化的最佳工艺条件为:上样液质量浓度2 mg/mL,流速2 mL/min,3 BV去离子水洗脱,然后用体积分数80%乙醇以2 mL/min的流速洗脱4 BV,可以使6-姜酚的纯度从1.54%提高到71.32%。     

双活塞液粘调速离合器动态特性研究

为了解决液粘调速离合器摩擦副偏磨问题,提高液粘调速离合器摩擦片运动系统的响应速度,提出了一种新型双活塞结构液粘调速离合器。基于摩擦片受力模型,推导出了双活塞结构液粘调速离合器摩擦片间油膜的动态平衡方程及传递函数,并对其动态特性进行了理论分析及仿真研究。结果表明:双活塞结构液粘调速离合器与单活塞的相比输出响应速度明显提高;在输出转速为80 rad/s时,其响应时间可由52 s减少到22 s。     

金银花多酚氧化酶特异性与抑制剂动力学研究

对金银花多酚氧化酶底物特异性和不同抑制剂的抑制效应进行了动力学分析,结果表明:金银花多酚氧化酶的最适作用底物为绿原酸,Km值为0.0059 mmol/L。维生素C、4-己基间苯二酚、L-半胱氨酸对多酚氧化酶的抑制均属可逆抑制,其抑制类型分别属于混合性、竞争性、反竞争性,对游离酶的抑制常数KI分别为1.620、4.587、0 mmol/L,对酶-底物络合物的抑制常数KIS分别为1.995、0、3.780 mmol/L;柠檬酸的抑制效应属不可逆抑制。维生素C、4-己基间苯二酚、L-半胱氨酸、柠檬酸对金银花多酚氧化酶半抑制浓度分别为0.062、0.053、0.140、0.048 mmol/L。     

宁夏生态移民可持续生计问题研究

依据可持续生计分析框架,利用宁夏已搬迁生态移民的实地调查数据,对移民农户的生计资本现状进行研究。结果表明：生态移民存在物质资本积累缺乏、人力资本薄弱、金融资本不足等问题。为了促进移民可持续生计的获得和发展,提出增加移民的物质资本和金融资本,重点着眼于以人力资本为主线的可持续发展能力培育的对策建议。     

劳务移民可持续生计问题研究--以宁夏为例

“十二五”期间宁夏将对34.6万人实施多种模式相结合的生态移民搬迁安置.以宁夏石嘴山劳务移民为研究对象,通过可持续生计框架研究,从自然资本、人力资本、物质资本、金融资本和社会资本5个方面进行移民的可持续生计调查.结果表明：石嘴山劳务移民主要存在受教育程度低、技能水平不高、金融资本和社会资本储备不足等问题,并提出相应的解决对策.     

丝羽乌骨鸡快大型新品系早期生长发育规律及肉用性能的研究

本试验对丝羽乌骨鸡快大型新品系的早期生长发育规律及肉用性能进行了系统的研究。利用Logistic模型确定了快大型新品系丝羽乌骨鸡的生长模型,并以此制定了标准生长曲线。研究结果表明,其生长拐点为:10.5周龄;在14周龄时体重约1.0kg,公、母鸡屠宰率分别达到85.88%、84.12%;胸肌率分别达到17.78%、17.28%;腿肌率分别达到24.38%、22.54%。在14周龄时,为较适合的上市日龄。     

Spatial–temporal variations in biosonar activity of Yangtze finless porpoise in the lower reaches of the Yangtze River and its correlation with underwater noise: Are quieter non-shipping branches the remaining shelters?

1. Yangtze finless porpoise (YFP) is Critically Endangered, It relies on its biological sonar sensing system for important life activities. The rapid development of the Yangtze valley has brought busy shipping, which has resulted in increased noise.
2. Two locations on the shipping channel and non-shipping branch were selected. Passive acoustic monitoring was used to record the biosonar signals of porpoises and underwater noise. The number of click trains, echolocation encounters, buzzes and buzz ratios were counted and the root mean square sound pressure level of noise was calculated in five diel phases.
3. A non-parametric test was used to analyse the differences among different phases and between different locations. The aim of the study was to detect the spatial and temporal variations in the biosonar activity of YFPs and underwater noise between non-shipping and shipping channels, and to provide scientific advice for YFP conservation.
4. Significant spatial and temporal patterns were observed both in biosonar activity and noise. Average biosonar activity, including click trains, buzzes, buzz ratio and echolocation encounters, was higher in the non-shipping channel than in the shipping channel, whereas the noise level was higher in the shipping channel than in the non-shipping channel.
5. In the non-shipping channel, the buzz numbers and buzz ratios, indicators of porpoise feeding activity, were higher at night than during the day while the noise level was higher during the day than at night.
6. These findings may be associated with the noise avoidance strategies of YFPs to adapt to the busy shipping on the Yangtze River. Maintaining the non-shipping status of some branches of the Yangtze River can provide more shelters for the YFPs. Strengthening the measures for banning navigation at night or reducing the vessel speed at night throughout the entire year would improve the YFPs’ feeding success.

     

Effects of body size and water temperature on food consumption and growth in the sea cucumber Apostichopus japonicus (Selenka) with special reference to aestivation

To investigate the effects of body size and water temperature on feeding and growth in the sea cucumber Apostichopus japonicus (Selenka), the maximum rate of food consumption in terms of energy (C_maxe; J day^?1) and the specific growth rate in terms of energy (SGRe; % day^?1) in animals of three body sizes (mean±SE) – large (134.0±3.5 g), medium (73.6±2.2 g) and small (36.5±1.2 g) – were determined at water temperatures of 10, 15, 20, 25 and 30°C. Maximum rate of food consumption in terms of energy increased and SGRe decreased with increasing body weight at 10, 15 and 20°C. This trend, however, was not apparent at 25 and 30°C, which could be influenced by aestivation. High water temperatures (above 20°C) were disadvantageous to feeding and growth of this animal; SGRe of A. japonicus during aestivation was negative. The optimum temperatures for food consumption and for growth were similar and were between 14 and 15°C, and body size seemed to have a slight effect on the optimal temperature for food consumption or growth. Because aestivation of A. japonicus was temperature dependent, the present paper also documented the threshold temperatures to aestivation as indicated by feeding cessation. Deduced from daily food consumption of individuals, the threshold temperature to aestivation for large and medium animals (73.3–139.3 g) was 24.5?25.5°C, while that for small animals (28.9–40.7 g) was between 25.5 and 30.5°C. These values are higher than previous reports; differences in sign of aestivation, experimental condition and dwelling district of test animals could be the reasons.