我国农民信息消费力现状与提升对策

在概述已有研究的基础上,构建了我国农民信息消费力评价指标体系,对2006年我国农村信息消费力进行了综合分析,并从提高政府重视程度、完善农村信息服务体系、采取有利措施保障农民增收等方面提出了相关建议。     

Unusual Navicular Bone Fractures in HindLimbs: Clinical and Imaging Findings

Three horses were identified with an unusual fracture configuration of a hindlimb navicular bone. All horses had unilateral lameness which was worse on a circle on a firm surface and was abolished by plantar nerve blocks performed at the base of the proximal sesamoid bones. Radiological findings included an ill-defined curvilinear radiolucent line along the distal horizontal border of the navicular bone in case 1; cases 2 and 3 had three fragments along the distal horizontal border, associated, in case 2, with marked abnormalities extending into the spongiosa of the bone. Lesions in case 2 were bilateral despite unilateral lameness. Fractures parallel to the distal horizontal border of the navicular bone have not been described in front limbs; neither have more than two fragments been observed along the distal border. One previous report describes a lesion similar to that in case 1 in a hindlimb navicular bone. Fragmentation of the distal horizontal border associated with rupture of the distal sesamoidean impar ligament and proximal displacement of the bone has been reported in hindlimbs. It is likely that biomechanical reasons are responsible for the occurrence of these lesions in hindlimbs.     

Environmental influences on Acinetobacter sp. strain BD413 transformation in soil

The ability of various environmental factors (root exudate from silver tussock, blue tussock, flax, wheat, ryegrass and lupin; simulated-root exudate; moisture; temperature; soil density; salinity; sewage sludge; fertiliser; pesticide) to promote or inhibit transformation of the soil-dwelling bacterium Acinetobacter baylyi BD413 (pFG4ΔnptII) was investigated using soil microcosm studies. A marker-rescue system was used to monitor the transfer of a functional nptII gene from exogenous chromosomal DNA to A. baylyi BD413 (pFG4ΔnptII). Significant differences were detected in A. baylyi BD413 (pFG4ΔnptII) transformation rates in three sterile New Zealand agricultural soils. Addition of simulated-root exudate to the sterile soil was essential for transformation of A. baylyi BD413 (pFG4ΔnptII) in the soil types tested, but addition of plant exudates collected from a variety of New Zealand cropping and native plants did not promote transformation rates to above detectable limits. Increases in soil temperature and bulk density increased the transformation rate but this effect was not consistent across all three soil types. Application of sewage sludge to sterile soils significantly increased transformation in the sandy soil but not in the silt loam and fine sandy loam soil types. Fertiliser (superphosphate) and herbicide (glyphosate) applied at agronomic rates did not affect transformation rates; however, when used at 5× and 50× the agronomic rate respectively, transformation was significantly reduced in all three sterile soils. These results suggest that competence and transformation of the A. baylyi BD413 (pFG4ΔnptII) in soils is highly dependent on the presence of nutrients and is also influenced by the soil texture.     

断根时间与半径对菊芋块茎生产性能及其水平分布规律的影响

通过测定不同断根时间（50、65、80、95和115日龄）和半径（切除1/5、1/4、1/3、1/2根系长度和不切割）条件下菊芋块茎生物量、数量、体积以及水平分布规律,探讨断根对菊芋块茎生产性能及其水平分布规律的影响,阐明断根提高菊芋块茎生物产量的机制。结果表明：65日龄断根条件下块茎生物量最高（980.07 g·株^-1）,1/2断根半径条件下块茎生物量最高（1 115.28 g·株^-1）;115日龄断根条件下块茎平均体积最大（5.79 cm³）,1/5断根半径条件下块茎体积最大（5.81 cm³）;65日龄断根条件下块茎数量最多（616.72个·株^-1）,1/2断根半径条件下块茎数量最多（654.93个·株^-1）;断根时间和半径对块茎生物产量均具有极显著影响（P<0.01）;断根处理条件下单位面积内菊芋块茎生物量和数量随距离主根中心距离的增加呈现逐渐减少的变化趋势;断根时间和半径对块茎数量、生物量和体积的影响随着距离主根中心距离的增加逐渐减弱。     

Structural characteristics of typical water conservation forests in mountainous areas of Beijing

Forest structure and function are both closely interconnected and interdependent. It is important to understand forests’ structural characteristics to utilize their functions effectively. In this study, we quantified and compared 112 water conservation forests in the mountainous areas of Beijing, which included 18 different forest types. We performed a holistic analysis, summarizing the forests’ structural characteristics in terms of water conservation and examining aspects of horizontal and vertical structures. The results showed that natural conservation forests had mostly unevenly aged, multilayered, mixed structure, while most artificial conservation forests exhibited even-age, single-story, and homogeneous structures with relatively low biomass. Understanding structural features may provide better insight into how forests affect water conservation and thus improve the sustainable management of forests for water conservation in Beijing.     

木材加工中心水平刨(刀轴)系统动静态特性研究

水平刨(刀轴)系统是木材加工中心的重要部件,其动态特性对加工工件的表面质量和加工误差影响很大。为获得水平刨(刀轴)系统的静动态特性指标,建立水平刨(刀轴)系统动力学数学模型,对其振动原理进行阐述;通过三维建模,借助于ANSYS软件对水平刨(刀轴)系统进行静力学分析、约束模态分析和谐响应分析,依据仿真结果对水平(刀轴)刨(刀轴)系统设计的合理性进行验证。所得研究成果可为类似问题的分析提供参考,故本研究具有一定的工程应用价值。     

人造板生产用导热油管道及支架设计

在综合分析人造板生产用导热油特点的基础上,计算3种不同压力导热油支架的水平应力和尺寸。简述导热油压力计算方法,提出降低压力的有效措施,为人造板行业导热油参数选择提供参考。     

化工污染场地氯苯分布特征

以某化工污染场地为研究对象,研究了该场地主要污染物氯苯在土壤中垂直和水平分布特征,分析了生产历史、场地水文地质等因素对氯苯空间分布的影响。结果表明:在重力和淋洗作用下,氯苯能够在黏土层和粉质黏土层中垂直迁移。氯苯在土壤中的垂直分布具有明显的富集特征,主要富集在12.0～15.6 m深的粉质黏土层中,其中14.4～15.6 m深的粉质黏土层污染最为严重,氯苯浓度高达1.0×10~4 mg/kg。在不同采样点位土壤中,氯苯浓度峰值出现的深度不同,在同一采样点位土壤中,氯苯出现多个浓度峰值,这与生产过程中氯苯的分批次、间歇性泄露有关。场地氯苯主要出现在氯苯存储、使用和处置及其附近区域粉质黏土层中,说明氯苯水平分布特征主要受企业生产功能分区影响,同时受场地水文地质的影响产生局部小范围扩散。     

贮木场平曲线原木输送机设置的探讨

平曲线原木输送机目前在贮木场中应用广泛,本文对平曲线原木输送机受力进行了分析,对如何减轻平曲线输送机运转中各部件的损伤提出了解决措施,并从理论上探讨了平曲线原木输送机曲线设置中各项参数的选择.     

果园视觉导航基准线生成算法

针对果园导航环境的复杂性,提出了一种基于图像处理的果园导航基准线生成算法。采用二维Otsu算法获取最优分割阈值,对色差R-B分量图进行二值化处理;根据水平投影曲线的一阶导数变化规律,提取树的主干区域(ROI);根据区域中邻近像素灰度值的变化规律,提取主干与地面的交点作为特征点;根据点的分布特性对其进行归类,并利用最小二乘法拟合左右边界线,提取边界线上各行中心点生成果园导航基准线。在不同场景中的实验结果表明,该算法对噪声的干扰有较强的鲁棒性,使导航基准线的生成准确率高于90.7%;处理一幅640×480像素的图像平均耗时小于119 ms,具有较好的实时性。