小车避障双目视觉识别系统的研发

For the reasons of the complex working environment and plenty of obstacles in facility agriculture, this paper studied the problem of identifying the obstacles by binocular vision recognition system.Binocular vision system was built up at first.OpenCV and Matlab were used for the binocular camera calibration respectively.Secondly, Bouguet algorithm was used to rectify the input images and analyse three kinds of matching algorithms.Then the smallest enclosing moment of the object could be extracted.At last, the distance between the objects was calculated and 3D reconstruction was used.The experimental results showed that the binocular vision system had high reliability, high real time, strong anti-interference ability and lower cost which can identify different obstacles with a wide application rage.It could satisfy the operational requirements of the unmanned control vehicle’s automatic obstacle avoidance in facility agriculture, and laid the foundation for vehicle obstacle avoidance and navigation.     

投影寻踪新方法在泥石流危险度评价中的应用

探讨了利用实码加速遗传算法的投影寻踪新方法的泥石流危险度评价模型,并给出了相应算法、实例及同其它方法对比应用,表明了利用投影寻踪方法来评价泥石流危险度是有效可行的,且取得了理想的结果。     

悖牛川径流年内分配变化规律研究

[目的]分析悖牛川径流年内分配变化特征,为流域水资源规划、管理和开发利用提供科学依据。[方法]根据悖牛川控制性水文站—新庙站1966—2010年实测月径流资料,分析年内分配不均匀系数、完全调节系数、集中度(期)等特性。并采用累积滤波器和Mann—Kendall秩相关法诊断各月径流量的变化趋势。[结果](1)总体上,悖牛川径流年内分配呈双峰型分布,其峰值分别出现在3和8月。径流年内分配很不均匀,8月份径流量达到最大值,占年径流量的37.63%;1月份降到最低值,仅占到年径流量的0.65%;(2)20世纪60—70年代的不均匀性和集中程度最大,80年代最小。最大径流出现在7月中下旬到8月上中旬,相对比较集中;(3)对于1966—2010年系列,各月径流量都处于显著减小的趋势。[结论]受气候和人类活动的影响,悖牛川月径流量年内分布不均且均呈现减少趋势。     

强还原土壤灭菌防控作物土传病的应用研究

随着集约化种植程度的不断提高,土传病原菌侵染、土壤酸化、次生盐渍化、养分平衡失调等引起的作物连作障碍发生率不断攀升,严重威胁着集约化农业的可持续发展。强还原土壤灭菌(Reductive Soil Disinfestation,RSD)法是一种作物种植前的土壤处理方法,即:在发生土传病害的土壤上,添加大量的易分解有机物料、灌溉、薄膜覆盖或淹水阻隔与大气的气体交换,快速创造土壤强还原环境,短期内杀灭土传病原菌的方法。强还原杀灭土传病原菌的作用机理包括:1)厌气杀灭好氧病原菌;2)还原过程产生有毒有害的物质杀灭土传病原菌;3)强还原改变土壤微生物群落结构,抑制土传病原菌活性。强还原土壤灭菌法还具有提高土壤p H,减轻次生盐渍化的作用,具有广谱性和环境友好性。本文介绍了该方法的起源、作用机理、影响该方法效果的因素及其应用前景。     

Characterization of humic acids extracted from sewage sludge-amended oxisols by electron paramagnetic resonance

In tropical soils, the high turnover rate and mineralization of organic matter (OM) associated with intensive agricultural use, generally leads to faster soil degradation than that observed in temperate climatic zones. The application of sewage sludge to the soils is one proposed method of maintaining soil organic matter, and is also an alternative method of disposing of this waste product. As well as containing large quantities of OM, sludge is also a significant source of supplementary nitrogen, phosphorus and other essential nutrients for plant growth. However, it is necessary to understand the qualitative and quantitative changes that take place in the OM in soil treated with sewage sludge. The approach of the present study was intended to identify possible structural changes caused by sewage sludge applications on soil humic acids (HAs). The HAs extracted from a Typic Achrortox under sewage sludge applications were characterized by electron paramagnetic resonance (EPR) spectroscopy. The soil samples were collected from a field experiment designed to evaluate the effects of different doses of sewage sludge on corn growth and development in Brazil. The sewage sludge originated from urban waste treated at the sewage sludge treatment station in the city of Franca, state of Sao Paulo, Brazil. The following soil treatments were studied: control (non-cultivated soil under natural vegetation (NC)), control soil amended with NPK (conventional corn fertilization) and four treatments N1, N2, N4 and N8 with applications of 3.5, 7, 14 and 28 Mg ha⁻¹ of sewage sludge (dry matter), respectively. HAs were extracted from the surface layer using the methodology of the International Humic Substance Society (IHSS). Fe³⁺ and VO²⁺ ions complexed with HAs, and also semiquinone-type free radical (SFR) at concentrations of approximately 2.0 × 10¹⁸ spins g⁻¹ HA were identified in EPR spectra. The levels of SFR were lower for treatments where the applied sewage sludge doses were equivalent to four and eight times the normal doses of N mineral fertilization, reaching values of 1.7 × 10¹⁸ and 1.24 × 10¹⁸ spins g⁻¹ HA, respectively. The observed decrease in SFR content as sewage sludge dose was increased, was probably associated with the incorporation of less aromatic components into HAs originating from the sewage sludge.     

Study on The Mode of Sectional Even Mass Cantilever of Silos And the Analysis Method of Infinite Degree of Freedom

In this paper,a new mode of sectional even mass cantilever of silos was established and an analysis of infinite degree of freedom for it was carried out.In the end,a calculation example of this precise,reliable and practical mode was given.     

Effect of Disturbance on the Cylindrical Cavity Expansion in Saturated Soft Clay

According to the fact that the undrained shear strength decreases in the field vane test,applying the cylindrical expansion theory and assuming that the saturated soft clay satisfies Tresca yield criterion,the disturbance degree function D is given on the basis of the sensibility of saturated soft clay.Considering that the undrained shear strength is the linear function of the disturbance degree D in plastic region,the elastic-plastic solution of the cylindrical expansion has been gained.     

灵芝连作障碍的研究进展

分析灵芝产业发展现状,指出连作障碍是灵芝段木栽培的最大制约因素。综述引起灵芝连作障碍的主要因素有土壤微生物种群特性的变化、灵芝产物的自毒作用,以及病原菌的增殖。相应的防控技术有覆沙出芝、采用液氨熏蒸灵芝连作土壤等,提出有换土与不换土多途径协同综合防治两种措施。     

酵母破壁程度测定方法的研究

酵母是饲料工业常用的一种单细胞蛋白,经破壁可以得到不同的深加工产品。根据酵母细胞破壁后细胞表面通透性增加以及蛋白质被酶解释放到酵母细胞外的特点,本实验采用革兰氏染色法、酸溶蛋白质检测法、氨基酸态氮检测法对未破壁的酵母粉、自溶酵母、外源酶解酵母进行检测对比研究。结果显示:(1)经革兰氏染色,3种酵母的颜色存在明显差异:酵母粉显示紫色,自溶酵母显示部分为紫色、部分为无色,外源酶解酵母显示无色;(2)外源酶解酵母、自溶酵母、酵母粉之间的酸溶蛋白质和氨基酸态氮含量存在显著差异(P<0.05),在外源酶解酵母中含量最高。本实验结果表明,采用革兰氏染色法可以区分酵母是否破壁;通过检测酸溶蛋白质和氨基酸态氮含量可以评估酵母产品的破壁程度。     

兽医专业学位研究生学位论文选题与质量管理

兽医专业学位研究生的学位论选题具有广泛性、交叉性、应用性和创新性四个特点，应在选题、研究和学位授予三个阶段的十个环节加强论质量管理。