汶川震区滑坡堆积体体积三维激光扫描仪测量与计算方法

2008年5.12汶川8级地震形成的大量松散滑坡堆积体,破坏农用地,损毁农田基础设施,对震区农业经济造成重大损失,严重威胁震区农业生产安全。本研究所选震区典型滑坡堆积体位于汶川县草坡乡,采用三维激光扫描仪实地测量滑坡堆积体,构建滑坡堆积体几何模型,计算滑坡堆积体体积。扫描仪到滑坡堆积体前、后缘的距离分别为25.74和79.00 m,距离扫描仪200 m处的扫描精度为20.0 cm×20.0 cm。根据扫描得到的滑坡堆积体点云数据,采用特征值法拟合近似滑坡堆积体的坡面、滑动面,构建滑坡堆积体几何模型。计算得到该滑坡堆积体体积为19 018 m3。建立了使用三维激光扫描仪测量和计算滑坡堆积体体积的方法。这种测量与计算方法可为地震受损农用地灾后的土地整理提供重要依据。     

EXCLOSURE LAND MANAGEMENT FOR RESTORATION OF THE SOILS IN DEGRADED COMMUNAL GRAZING LANDS IN NORTHERN ETHIOPIA

In the northern highlands of Ethiopia, establishment of exclosures to restore degraded communal grazing lands has been practiced for the past three decades. However, empirical data on the effectiveness of exclosures in restoring degraded soils are lacking. We investigated the influence of exclosure age on degree of restoration of degraded soil and identified easily measurable biophysical and management‐related factors that can be used to predict soil nutrient restoration. We selected replicated (n = 3) 5‐, 10‐, 15‐, and 20‐year‐old exclosures and paired each exclosure with samples from adjacent communal grazing lands. All exclosures showed higher total soil nitrogen (N), available phosphorus (P), and cation exchange capacity than the communal grazing lands. The differences varied between 2·4 (±0·61) and 6·9 (±1·85) Mg ha⁻¹ for the total N stock and from 17 (±3) to 39 (±7) kg ha⁻¹ for the available P stock. The differences in N and P increased with exclosure age. In exclosures, much of the variability in soil N (R² = 0·64) and P (R² = 0·71) stocks were explained by a combination of annual average precipitation, woody biomass, and exclosure age. Precipitation and vegetation canopy cover also explained much of the variability in soil N (R² = 0·74) and P (R² = 0·52) stocks in communal grazing lands. Converting degraded communal grazing lands into exclosures is a viable option to restore degraded soils. Our results also confirm that the possibility to predict the changes in soil nutrient content after exclosure establishment using regression models is based on field measurements. Copyright © 2011 John Wiley & Sons, Ltd.     

雷州黑鸭血液生化性状与体尺性状、肉品质性状间的相关性分析

为研究雷州黑鸭血液生化性状及其与体尺和肉质性状间的关系,随机选取12只300日龄雷州黑鸭（公、母各半）进行测定分析。结果显示：谷丙转氨酶（GPT）与骨盘宽呈显著性正相关,乳酸脱氢酶（LDH）与肌肉粗蛋白含量与半潜水长均呈极显著相关,与蒸煮损失率与胸宽呈显著相关,肌肉pH、胸宽与骨盘宽均呈显著性正相关,胸宽和骨盘宽均和半潜水长呈极显著正相关。典型相关分析结果为：血液生化性状跟体尺性状和肉品质性状间的第1个典型相关系数分别为0.874（P<0.05）、0.901（P<0.05）,分别占2组性状总相关信息的81.2%和90.6%,体尺性状和肉品质性状间的第1个典型相关系数为0.901（P<0.05）,占2组性状总相关信息的75.4%。结果表明,在3组性状中LDH、胸宽、半潜水长、肌肉pH和肌肉粗蛋白含量起主要作用,血液生化性状和肉质性状在3组性状间的相关性最高。     

基于前沿面理论的中国农业机械生产配置效率分析

定量分析农业机械生产配置效率,可以为科学制定和正确执行中国农业机械化政策提供重要的理论支撑。该文利用1991-2009年中国大陆31个省(市、区)的农业投入和产出的面板数据,采用随机前沿分析方法对农业机械生产配置效率进行了测算,并分析了其变化趋势和空间分布特征。结果显示:1991-2009年间中国农业机械生产配置效率平均为64.65%,呈现出波动之中上升的趋势;各区域的平均值显示,东北地区最高,华东地区次之,西北地区最低,西南地区、华北地区和中南地区位于中间;农业机械生产配置效率的演进规律在各区域之间呈现多元化。     

基于浮标原理的原位高频检测电导率变送仪设计

为了实时监测水域盐度的变化及动态分析其盐度值常年分布规律,该文设计了一种基于浮标原理原位高频检测电导率的变送装置。所设计变送器选用低功耗的MSP430F149微处理器,通过SIM300的GPRS通讯模块,在河流、湖泊和水产养殖场等水域实现了GPRS网络覆盖区域内的远程数据采集。系统选用线性插值的方法对其中的温度电导率传感器进行了温度补偿,补偿精度为±5%FSC。该研究成果可为野外水域水质在线监测提供一种有效的解决方法。     

Wind field measurement for supplementary pollination in hybrid rice breeding using unmanned gasoline engine single-rotor helicopter

无人驾驶直升机具有机动灵活、不需要专用机场等特点,目前已在农业航空植保中得到应用。杂交水稻制种中,利用无人直升飞机飞行时其旋翼产生的风力能使父本花粉传播更远,可扩大父本和母本相间种植的宽度,实现父本和母本的机械化耕种和收割,从而实现制种全程机械化。杂交稻制种辅助授粉的效果(母本异交结实率)、作业效率及经济效益与无人直升机飞行时产生的风速、风向和风场宽度等参数密切相关,但迄今尚不明确。该文采用风场无线传感器网络测量系统组成三向风速测量线阵和单向风速面阵在水稻田里对无人油动单旋翼直升机飞行时的风场进行了测量试验,目的在于探明无人直升机在辅助授粉作业时不同方向的风速和风场宽度等参数,以便决策出较佳的飞行作业参数,包括飞行高度、作业航向等。无人直升机授粉作业的飞行速度设置为3 m/s,作业载荷为3.75 kg,飞行高度为：9、8、7和6 m,测量的风向为：平行于飞行方向（X）、垂直于飞行方向（Y）、垂直于地面方向（Z）。测量试验结果表明,上述3个风向的风速值大小排序为VX>VY>VZ,且风速持续稳定,因此,在直升机辅助水稻授粉作业时,平行于飞行方向的风力（即沿着直升机前进方向的飞机尾风）更有益于辅助授粉作业;随着飞行高度不断降低,风场宽度亦有所增加,在飞行高度为6～8 m时,达到3级风的风场宽度最大可达到9 m,飞行高度为9 m时,达到3级风的风场宽度最大仅为4 m,明显缩小,综合考虑农艺要求、作业效率及安全性等因素,该文建议无人驾驶油动单旋翼直升机Z3机型的较佳飞行作业高度为7 m;直升机逆自然风方向飞行作业时到达水稻冠层的风力较小,很难形成能满足水稻制种授粉所需的风场宽度和风速,而顺风方向飞行时的风场宽度和风速较大,因此采用油动力无人直升机辅助水稻制种授粉时,宜避免逆自然风方向飞行作业。该研究可为无人直升机水稻制种辅助授粉技术的发展提供参考。     

四川会理县农业地质灾害形成机理及危害研究

在遥感解译和野外调查的基础上,对会理县农业地质灾害进行归类和分区,从地形地貌、地质结构及岩性组合、气候、地震和人类活动等方面探讨了地质灾害的形成原因,分析了其对农业生产的危害,并提出了防治措施。     

Do habitat measurements in the vicinity of Atlantic salmon (Salmo salar) parr matter?

Atlantic salmon, Salmo salar L., parr habitat characterisation is usually performed by in situ measures of key environmental variables taken at the exact fish location if the fishing gear allows precise pinpointing of this location, or in large sampling sections covering a river reach or mesohabitat, often ignoring variability in the immediate vicinity around individual fish. These data may be critically important in the development and validation of habitat preference models. The influences of seven increasing distances of measures, the variation of the number of considered measures and the depth of velocity measurement (bottom or 0.6 of the depth) in the calculations of HSI (Habitat Suitability Index) from a multiple‐experts fuzzy model of Atlantic salmon parr habitat were tested. When a parr was present, six measures collected in a 50‐cm radius around the fish to provide an average measure as input data and velocity measured at 60% of the depth gave the highest HSI values. These results show some potential for the use of an intermediate study scale, between micro‐ and mesohabitat, and questions how fish habitat conditions are currently measured.     

坡面水流滚波特征参数超声波自动测量系统构建与试验

精确高效的观测手段是深入研究坡面薄层水流特性的基础。基于系统集成理论和自动化测量原理,结合高精度超声波水位传感器,研制坡面水流滚波特征参数测量系统。在光面玻璃床面,5种坡度和5种单宽流量条件下进行实际测量应用,评价测量系统的精确度及稳定性,并与人工测针法和目测法测量结果比较分析。结果表明,测量数据相对误差为0.23%,变异系数为0.66%;测量系统和传统测量方法测得的滚波波峰值最为接近,滚波频率、波速和波长的接近程度依次减弱;相比人工测量方法,超声波测量操作简便,自动化程度高且能够进行持续稳定观测,具有较好地测量精度和可靠性,能够满足坡面水流滚波特性研究需求。研究成果在坡面水流测量手段改进方面具有广阔的运用前景。     

Temperature dependence of relaxation spectra for highly hydrated gluten networks

In the present investigation, the temperature dependence (0–50 °C) of the relaxation spectrum of hydrated gluten was studied using novel numerical algorithms. Tikhonov regularization, in conjunction with the L-curve criterion for optimal calculation of the regularization parameter, was used to generate the relaxation spectrum from stress relaxation measurements on shear. The methodology used revealed six molecular events with baseline resolution that could be grouped into fast- and slow-relaxation regimes. The fast-relaxation regime exhibited strong temperature dependence whereas the slow one is temperature independent indicating on the whole two dominant mechanisms of interactions. The “loop and train” structural model for gluten interactions was found adequate to describe the relaxation events in this system, with the fast regime being assigned to interactions due to hydrogen bonding whereas the slow one to permanent cross-linking of the entire network. Findings of the present investigation provide fundamental understanding and give new insights into the complexity of interactions and relaxation modes of hydrated gluten.