我省胶合板工业发展的探讨

本文在分析了胶合板市场发展前景和云南胶合板生产现状的基础上，对建立云南胶合板用材林基地；提高产品质量，生产适销对路的规格品种；提高技术水平，完善生产装备；加强经营管理，降低生产成本等方面提出了有益的建议。     

冷却水循环用离心泵汽蚀的原因与防止方法探讨

通过对冷却水循环用离心泵产生汽蚀的因素进行分析，提出了防止汽蚀产生的技术措施，经生产应用效果良好。     

南粤古驿道保护修复工程做法研究

针对近几年广东省在南粤古驿道保护修复工程做法方面取得的实践工作经验,总结了南粤古驿道分类及分级,南粤古驿道用材区域概述、保护与修复原则、修复程序、典型古驿道修复做法、修复施工要求等内容。通过梳理修复工程方法,规范其修复技术步骤及施工标准,防止建设性的破坏,再现历史工艺。     

带分流叶片的离心泵叶轮三维贴体网格生成

采用泊松方程进行带分流叶片的离心泵叶轮内三维贴体网格的自动生成 ,并通过源项控制来满足网格的正交性及调整网格疏密。计算时根据边界处网格线正交的控制角和控制距离的几何约束确定边界条件 ,利用分块粘接技术生成了带分流叶片离心泵叶轮内的三维分块结构化贴体网格 ,从而提高了流场流动分析中前处理环节的效率和精度 ,能使在湍流计算中广泛应用的壁面函数法的条件容易满足 ,并能使普遍采用的压力第二边界条件直接用于计算中 ,还能满足差分要求 ,减小离散误差。     

大型排灌工程项目后评价理论及方法

大型排灌工程项目后评价是大型排灌工程项目科学管理的重要环节。根据大型排灌工程的具体特点 ,讨论项目后评价的理论基础和评价方法 ,分析了大型排灌工程项目后评价的特点、内容、基本原则和程序 ,提出了后评价的指标体系及各种指标的计算方法。     

Effect of mineral nitrogen fertilizer forms on N2O emissions from arable soils in winter wheat production

Nitrogen fertilizers are supposed to be a major source of nitrous oxide (N₂O) emissions from arable soils. The objective of this study was to compare the effect of N forms on N₂O emissions from arable fields cropped with winter wheat (Triticum aestivum L.). In three field trials in North‐West Germany (two trials in 2011/2012, one trial in 2012/2013), direct N₂O emissions during a one‐year measurement period, starting after application of either urea, ammonium sulfate (AS) or calcium ammonium nitrate (CAN), were compared at an application rate of 220 kg N ha^?1. During the growth season (March to August) of winter wheat, N₂O emission rates were significantly higher in all three field experiments and in all treatments receiving N fertilizer than from the non‐fertilized treatments (control). At two of the three sites, cumulative N₂O emissions from N fertilizer decreased in the order of urea > AS > CAN, with emissions ranging from 522–617 g N ha^?1 (0.24–0.28% of applied fertilizer) for urea, 368–554 g N ha^?1 (0.17–0.25%) for AS, and 242–264 g N ha^?1 (0.11–0.12%) for CAN during March to August. These results suggest that mineral nitrogen forms can differ in N₂O emissions during the growth period of winter wheat. Strong variations in the seasonal dynamics of N₂O emissions between sites were observed which could partly be related to weather events (e.g., precipitation). Between harvest and the following spring (post‐harvest period) no significant differences in N₂O emissions between fertilized and non‐fertilized treatments were detected on two of three fields. Only on one site post‐harvest emissions from the AS treatment were significantly higher than all other fertilizer forms as well as compared to the control treatment. The cumulative one‐year emissions varied depending on fertilizer form across the three field sites from 0.05% to 0.51% with one exception at one field site (AS: 0.94%). The calculated overall fertilizer induced emission averaged for the three fields was 0.38% which was only about 1/3 of the IPCC default value of 1.0%.     

新疆特早熟陆地棉纤维细胞发育过程的超微结构观察

 利用透射电镜观察新疆特早熟陆地棉新陆早36号纤维发育过程中的超微结构变化。在10 DPA纤维细胞初生壁形成期,液泡占据纤维细胞中央,细胞质中有大量的线粒体、内质网、高尔基体等细胞器,初生壁较薄且厚度均匀;在20 DPA时,纤维在初生壁内已明显有一层薄薄的次生壁的形成,细胞质中细胞器部分解体;随后次生壁增厚速度逐步加快,在30 DPA到40 DPA之间,纤维平均增厚速度约为每天0.139 m,在40 DPA到50 DPA之间,纤维平均增厚速度约为每天0.47 m。纤维细胞次生壁向内层逐步层层加厚,形成“日生长轮”。随着纤维细胞的脱水成熟,纤维细胞次生壁增厚使纤维中腔只剩下一条窄缝。观察结果表明,虽然特早熟陆地棉发育进程快,开花早,但纤维细胞的发育进程与所报道的其它棉花品种具有相似性。     

内导叶滚筒式收鱼机设计与实验

针对深海域网箱养殖人工收鱼效率低、且劳动强度大,吸鱼泵等传统收鱼装置鱼损率高、需要装备大功率发电系统、不适合中小型收鱼船作业等问题设计了内导叶滚筒式收鱼机。对该装置的主体结构进行仿真,确定了主体结构发生最大等效应力和应力集中的位置,根据仿真结果进一步优化结构,并试制了实验装置。通过实验得出最优控制方案,即在倾角10°、转速15.3r/min情况下,有效输送量与功耗比最优,且滚筒在不同倾角下最优转速为15r/min,实验鱼损率为0.1%,满足用户要求。该装置能在保证一定收鱼效率的同时降低鱼损率,适合中小型渔船收鱼作业。     

活动导叶分布圆直径对混流式水轮机水力性能的影响

对于混流式水轮机,活动导叶与固定导叶以及转轮的相对位置直接影响导水机构和转轮内部流动,对水轮机安全、稳定、高效运行起到重要作用。采用商业软件ANSYS CFX 16. 0对某电站水轮机模型机全流道进行三维数值模拟计算,提出了5种活动导叶分布圆直径方案,分析不同方案下水轮机的外部能量特性与内部流场,寻找活动导叶安放的最佳位置。结果表明:适当增大活动导叶分布圆直径,可以有效改善叶片吸力面的低压区,降低活动导叶流域内水流的最大速度,改善转轮进口水流角,同时减小导水机构与转轮的水力损失。小流量工况下,D_0/D_1增大0. 031,水轮机效率提高了5. 28个百分点;设计工况与大流量工况下,活动导叶分布圆的变化对水轮机效率的影响相对于小流量工况较小,最高效率与最低效率的差值分别为0. 17%与0. 48%。因此,在一定范围内改变活动导叶的分布圆直径具有可实施性,对水轮机的优化设计有一定参考价值。