Cacao-fruit tree intercropping effects on cocoa yield, plant vigour and light interception in Côte d’Ivoire

A major challenge for cocoa producers in Côte d’Ivoire is to seek alternative shade trees or crop associations to adapt their planting devices and techniques to the shortage of forests. The recent tendency developed by farmers is to plant simplified orchards combining cacao and fruit trees. An on-farm trial was set up in a 5-year-old cocoa farm to compare a cacao monocrop planted at densities of 1,115 trees ha^?1 with cacao intercropped with orange or avocado trees, both at 44 trees ha^?1. Observations were done on incident light received by the cacao, vigour, growth and cocoa yields. On average, the cacaos received 100 % light in the monocrop, 89.6 % under orange trees and 80.6 % of incident light under avocado trees. They yielded 64.0 pods tree^?1 year^?1 in the monocrop (equivalent to 2.54 kg dry cocoa beans tree^?1), 30.3 pods tree^?1 when combined with orange trees and 28.3 pods tree^?1 with avocado trees. The two combinations allowed cocoa yields equivalent to those observed in the region (0.58 kg dry cocoa beans tree^?1). Vigour and yield were very highly correlated with the incident light received. Both the yield and the incident light are a logistic function of the planting distance from the shade tree. The inflexion point of the logistic functions corresponds to the minimum planting distance between the cacao and the intercropped fruit trees. On this basis, we suggest that the cacaos should not be planted closer than 6.50 ± 0.2 m to the orange or avocado trees.     

Dyeing behavior of laser-treated polyester

Polyester fabric was pre-treated with laser, followed by dyeing. The experimental results revealed that the rate of dyeing was greatly increased but the final percentage of dye exhaustion at equilibrium did not show any significant change. Based on the thermodynamic parameter of dyeing, it was concluded that laser treatment could provide the possibility of developing a low temperature dyeing process. Morphological and thermal studies revealed that obvious surface structure changes occurred. In the morphological analysis, ripple-like structure was found after laser treatment. This ripple-like structure may have captured more dye particles which could improve the dyeing behavior of polyester fibre. On the other hand, thermal analysis result revealed that the surface of polyester becomes highly amorphous on laser treatment, due to ablation. Meanwhile, XPS analysis showed that hydrophilic functional groups were introduced on to the laser-treated polyester fibre surface. As a result, surface physical and chemical changes induced by laser affect the dyeing behavior of polyester fibre. However, the laser treatment could not impart any adverse effect on color fastness to crocking and washing.     

基于水系生态保护的林业调查规划研究

以水系林业生态保护为目标,采用问题研究与目标导向相结合、规划研究与实施应用相结合的技术路线,全面调查分析了沂蒙山区水系分布状况及林业资源现状,进行了以水系林业生态保护为目的林业生态建设区域和类型划分,开展了重点区位水系林业生态保护专项研究与专项规划设计。     

The reasonable scale of water reuse system in irrigation area: a case study of Chitong irrigation district in Taiwan

The aim of this study is to assess the potential of the irrigation return-flow in a water reuse system, for the supply of other local water users. Both field survey and water-budget analysis were conducted, and the Chitong irrigation district in Taiwan was selected as the case study area. The results indicate that through the regulation of a pond with the effective capacity of 20,000 m³, a stable supply of 10,000 CMD of reuse water can be generated if the return-flow from the irrigation area of 200 hectares, which is about the size of a rotation plot, is intercepted. However, as the irrigation and effective rainfall are low from December to March, which are considered high risk for water supply, the irrigation return-flow decreases accordingly, and a series of responding measures are also suggested.     

惠州市中心城区道路绿地植物群落特征及配置模式研究

以惠州市惠城区主要道路两旁道路绿地作为研究对象,通过样方法对植物群落进行了调查,总结了城市道路绿地植物群落的生长发育规律和总体特征,对所形成的植物群落进行了综合评价分析,进而对道路绿地植物配置提出了相关建议和优化模式,为今后建设城市道路绿地提供科学的理论指导。     

密植枣园枝条粉碎还田机设计与试验

为解决新疆密植枣园果树枝条修剪量大、处理困难、人工劳动强度大及配套装备短缺等问题,研制了一种牵引式枝条粉碎还田机,主要由捡拾装置、粉碎装置和传动装置等组成。为此,主要阐述了机具整体设计方案和工作原理,并对其捡拾机构和粉碎机构等关键部件进行了理论分析和结构设计。捡拾装置通过上下捡拾辊与底部叉板相互作用对枣枝进行拾取和折断,提高了捡净率与粉碎效率;枝条在动定刀配合下被切断,并与筛片产生撞击,实现了高效粉碎。为获得粉碎还田机最佳工作效果,以刀轴转速、刀片数量、筛孔大小、枝条含水率和捡拾转速为试验因素,以捡净率和粉碎粒度为试验指标,进行了五因素二水平二次回归正交旋转中心组合优化试验,利用Design-Expert软件对该模型进行优化求解得到最佳参数组合。结果表明:在地形平坦、枝条含水率2 5%±3%的情况下,该机以2 km/h的速度进行粉碎作业时可获得较佳粉碎效果。该速度下,主要指标平均粉碎效率若羌灰枣枣枝(轻剪)为600kg/h,若羌骏枣枣枝(重剪)为1 500kg/h,平均枝条捡净率为92%,粉碎粒度(小于5cm)达89.3%。该研究可为解决新疆密植枣园枝条机械化处理技术提供参考。     

基于重叠网格的水轮机导叶尾流水动力特性数值研究

为研究水轮机导叶运动对水轮机暂态过程中叶栅流场的流固耦合动态特性影响,基于二维时均瞬态N-S方程和标准k-ε湍流模型,分别应用ANSYS FLUENT软件中的重叠网格方法和动网格方法,对高雷诺数下槽道内水轮机单个导叶在均匀来流条件下模拟水流绕流翼型叶片的导叶匀速关闭运动过程.结果表明:2种方法得到的关闭过程中叶后不均匀流场动态水力特性呈现出强非线性,导叶的升力系数、阻力系数随时间的变化规律较为吻合,槽道内各典型时刻的流场压力、尾涡结构、湍流强度分布特征也基本一致.但重叠网格方法的网格数量约为动网格方法的1/3,计算耗时约为动网格方法的1/4,说明重叠网格方法在计算效率方面具有比动网格方法更好的优越性.研究表明2种方法都可较好地模拟导叶动态绕流问题,但对某些复杂非线性动边界流固耦合问题进行非定常流模拟时可以优先选择重叠网格方法,2种方法都具有较高工程应用价值.     

胡萝卜复合火腿和香肠的质构特性及显微结构(简报)

为探索蔬菜复合肉制品品质特性的评价方法,分别用物性分析仪和扫描电镜研究了胡萝卜复合火腿和香肠的质构特性和显微结构。质构测定结果表明:与对照组相比,HLB-1复合火腿(鲜胡萝卜25%)和HLB-2复合火腿(胡萝卜粉2.5%)的硬度分别降低了70.94%和57.23%,咀嚼度分别降低了64.81%和34.86%;与对照组比较,胡萝卜复合香肠(鲜胡萝卜25%)的硬度和咀嚼度分别降低了30.84%和51.30%。感官评定结果表明:与对照组比较,胡萝卜复合火腿和香肠的口感更柔和细腻、嫩度更好。通过扫描电镜对产品结构的观察表明:在添加了鲜胡萝卜的火腿和香肠中均发现了圆形光滑的小颗粒状物质,复合肉制品内部的细微结构均匀、结构比较膨松,这在一定程度上解释了胡萝卜复合火腿和香肠的感官和质构特征。     

大型贯流式泵站快速门加速启动过渡过程

为研究大型贯流式泵站机组闸门加速启动过程中的外特性参数变化及流态变化,对灯泡贯流泵机组进行三维建模,采用Fluent软件中的UDF来控制闸门的启动过程,使用铺层法动网格技术来控制闸门处网格生成与消灭,并设定S-A模型作为湍流模型,对灯泡贯流泵机组启动过程进行瞬态数值模拟.计算结果表明:当贯流泵机组快速门以10倍设计速度启动时,机组的转速与流量将以更快的速度达到额定转速与额定流量,同时瞬间最大倒灌流量相比未加速启动时增加了30%.当贯流泵机组处于倒流状态时,靠近轮毂处叶轮叶道压力面的压强呈现出从叶轮进水边向出水边逐渐递增的分布规律.当机组处于零流量的临界状态时,混乱的流态导致压力集中及脱流现象加重,叶轮进水边负压区范围扩大且程度加深.     

苗期调控对晚播小麦产量及氮素利用的影响

针对冬小麦因播期推迟造成产量损失的问题,以2个不同分蘖能力的冬小麦品种中麦8号和航麦501为供试材料,研究苗期覆膜和补施氮肥对晚播小麦产量及氮素利用的影响。试验设置3个播期：10月5日适期播种（S0,对照）、10月15日适当晚播（S1）和10月25日过晚播（S2）。结果表明：随着播期推迟,小麦产量逐渐降低。晚播条件下,苗期覆膜和补施氮肥可调控冬小麦产量构成因素、农艺性状、茎蘖生长、成穗率以及氮素的吸收利用。综合而言,晚播条件下,覆膜和补施氮肥有利于提高小麦穗长、总小穗数及冬前群体数量;同时,覆膜可显著提高2个品种晚播条件下的分蘖成穗率和过晚播条件下的植株氮素积累量（PNA）及氮肥偏生产力（PFP）,增幅分别为46.4%~89.1%、12.7%~26.5%和19.5%~20.1%;补施氮肥在过晚播条件下有利于成穗率的提高,增幅为18.5%~34.7%。2种调控措施均有利于增加晚播小麦产量,增幅达1.4%~19.5%。但不同分蘖力的小麦对2种调控措施的响应存在差异。综合考虑产量及氮素利用等各方面因素,在晚播条件下,相比于补施氮肥,苗期覆膜更有利于提高晚播小麦产量,弥补晚播造成的产量损失,但在实际操作和节约生产成本方面,前者优于后者。