基于加权Voronoi图的林木竞争指数

以福寿山林场25年生的杉木生态公益林为研究对象,通过分析林木竞争指数与胸径生长因子的相关关系,得出二者为负相关,从而确定加权Voronoi图的权重为胸径倒数(W),借助Arcgis软件里的加权Voronoi图工具,通过加权Voronoi图的方法来确定竞争单元,提出基于加权Voronoi图的W_V_Hegyi竞争指数,最后将W_V_Hegyi竞争指数与Hegyi、V_Hegyi竞争指数进行对比分析,结果表明:1) 3种竞争指数与胸径相关性强弱排序为:W_V_HegyiV_HegyiHegyi;2) 3种竞争指数与胸径服从幂函数关系,曲线拟合度排序为:W_V_HegyiV_HegyiHegyi;3) 样地竞争指数平均值排序均为:V_HegyiW_V_HegyiHegyi。通过以上比较分析证明,W_V_Hegyi竞争指数比Hegyi、V_Hegyi竞争指数能更准确地反映林木间的竞争关系。      

气吸式大豆精密排种器排种性能试验研究

在精密播种机中,精密排种器是其工作的核心部件,工作性能直接制约了播种机播种性能的优劣。为了探究影响气吸式排种器工作性能的主次因素,以大豆气吸式排种器为研究对象进行了台架性能试验测试。试验确定排种盘转速为影响排种器排种性能的主次因素,气室负压为次要因素;排种盘转速为20 r/min,气室负压为5 k Pa时该大豆气吸式排种器排种性能最优,合格指数高达91.13%。该研究结果对排种器结构改进以及性能优化提供了参考依据。     

耕地损毁鉴定指标体系研究

耕地损毁主要包括以下五种类型:耕地地面硬化、耕地地面塌陷、耕地挖损、耕地压占和耕地污染,笔者在分析耕地损毁类型特征基础之上,提出了耕地损毁鉴定体系指标选取的原则:综合性原则、分类指导原则、可操作性原则和耕地破坏程度认定与耕地恢复难易程度认定相当原则,由此得到耕地损毁程度的评价指标,采用层次分析法建立耕地损毁评价指标体系,并提出了完善法律法规,依法治理损毁、分类治理利用,推进耕地复垦、引导科学种田,加强耕地保护、创新防控机制等治理对策。研究结果可为耕地损毁鉴定、复垦方案的编制、复垦措施提供现实指导意义。     

Radiation interception and radiation use efficiency of potato affected by different N fertigation and irrigation regimes

Three years of field experiments were carried out to explore the response of potato dry matter production, accumulated intercepted photosynthetic active radiation (Aipar) and radiation use efficiency (RUE) to five N levels providing 0, 60, 100, 140 and 180 kg N ha⁻¹ and three drip irrigation strategies, which were full, deficit and none irrigation. Results showed that, irrespective of years, dry matter production and Aipar were increased by prolonged N fertigation, even though N fertigation was carried out from middle to late growing season. The highest total and tuber dry matter and accumulated radiation interception in all three years were obtained when potatoes were provided with 180 kg N ha⁻¹. RUE on the other hand was not affected by N regime. Thus, increases in total dry matter production with increasing N levels were essentially caused by higher Aipar. The strongest response to N fertilization occurred when most N was applied early in the growing season and the latest N fertilization should be applied no later than 41–50 days after emergence. Deficit irrigation, which received ca.70% of irrigation applied to full irrigation, did not reduce radiation interception and radiation use efficiency.     

Density responses and spatial distribution of cotton yield and yield components in jujube (Zizyphus jujube)/cotton (Gossypium hirsutum) agroforestry

Trees are the dominant species in agroforestry systems, profoundly affecting the performance of understory crops. Proximity to trees is a key factor in crop performance, but rather little information is available on the spatial distribution of yield and yield components of crop species under the influence of trees in agroforestry systems. Also, little information is available on how crop density may be exploited to optimize the yield in such systems. Here we studied the performance of cotton in jujube/cotton agroforestry. Field experiments were conducted in 2012 and 2013 in Hetian, Xinjiang, China. Cotton was grown at a row distance of 60 cm in three densities, 13.5, 18.0 and 22.5 plants m⁻² in six m wide paths between tree lines in a jujube plantation. Plant density affected both cotton aboveground dry matter and yield significantly. The highest yield was attained at the intermediate density of 18.0 plants m⁻² (20.0 plants m⁻² corresponding in sole cotton), lower than the optimal density in sole cotton (25.0 plants m⁻²). Yield at the lower density was constrained by the low number of bolls per m² as a direct consequence of the low density, whereas at the high plant density yield was constrained by a lower allocation of assimilates to cotton seed and lint, as a consequence of intraspecific and interspecific competitions. There were strong gradients in yield and yield components in relation to the distance from the tree rows. Leaf area and total dry matter of cotton in rows close to the tree lines were reduced, especially in the rows next to the trees. Moreover, biomass allocation to cotton fruits was reduced in these rows. Competitive influences from the trees on cotton performance extended two rows deep in a six-year old jujube stand, and even three rows deep in a seven-year old stand. Shading effects on cotton yield were compensated by increasing plant density as a result of greater boll numbers per unit ground area. Data from this study help guide the design of optimal plant density of cotton in jujube plantations and give insight in the spatial distribution and dynamics of competitive effects in agroforestry systems in general.     

基于企业社会责任的可持续供应链风险评价——以汽车行业为例

现代企业的竞争由企业间品牌竞争转向为供应链之间的竞争，可持续供应链管理中企业承担社会责任，是提高企业竞争优势、顺应社会责任指南标准化趋势的必然要求。可持续供应链中企业社会责任的复杂性、因果关系暧昧性和历史变化性使得社会责任实践存在一些困难。为了对可持续供应链管理中企业的社会责任进行有效治理，我们得在可持续供应链中纳入企业社会责任共同治理标准，对企业社会责任进行风险评价、监督与管理。     

毕节市漆树品种产量与树皮性状的灰色关联度分析

为漆树优良品种的选择以及灰色系统理论在林业林木品种评价上的运用提供参考，对毕节市8个漆树品种红漆大木、粉皮大木、灯台大木、红尖大木、肤胭皮、粉红皮、白杨皮、青杠皮等树皮解剖中6个主要性状与产漆量的关系进行灰色关联度分析。结果表明：漆树树皮解剖的单个性状对产漆量有直接影响，其中以漆汁道直径的大小关系最重要，直接关联度达0．7964；其次是活皮漆汁道单位面积与活皮厚度。从树皮解剖的综合性状看，漆树品种最好的依次是红尖大木＞红漆大木＞肤胭皮＞灯台大木＞白杨皮＞粉皮大木＞粉红皮＞青杠皮。分析结果与实际生产基本一致，表明在林业生产中运用灰色关联分析进行综合评价是可行的。     

沟槽滤棒压降影响因素的因子分析

[目的]深入研究沟槽滤棒特征参数及组成材料对滤棒压降的影响。[方法]选取常见的8种不同规格的沟槽滤棒及其主要组成材料为分析对象,采用相关性分析与因子分析,开展9个主要特征参数对沟槽滤棒压降的影响程度研究。[结果]试验表明,影响沟槽滤棒压降的特征参数间存在显著或极显著的相关性,相关系数矩阵中特征值大于1.0的前3个成分的累计贡献率达87.502%;由沟槽滤棒压降影响特征参数的旋转因子载荷矩阵得到3个公因子,总结定义后分别是:丝束总质量因子、单丝线密度/纤维素纸物理特性因子、沟槽特征参数因子。[结论]因子分析得出的公因子影响情况与实际沟槽滤棒生产检验过程中出现的情况基本吻合,进一步证实了沟槽滤棒特征参数对滤棒压降影响的准确性。     

基于案例推理的产品质量安全风险评估研究

为了建立健全产品质量安全风险管理体系，加强产品质量安全风险预警的要求，同时最大程度地利用过去成功的风险评估案例，构建了基于案例推理的产品质量安全风险评估系统。针对某种产品，根据专家的知识建立风险评估指标体系，并将每个评估指标赋权重，计算与案例库中的各个案例相似度，寻找出最大相似度案例，据此，辅助相关人员对目标案例进行风险分析与评估。     

花生副产物在畜牧生产中的综合利用

花生在生产过程中产生大量副产物,其营养价值较高,是重要的饲料加工原料。文章主要针对花生生产过程中副产物营养价值及在畜牧生产中的利用进行综述。