细分外推与模糊预测在近海水质非线性时序处理中的比较分析

近海水质非线性时间序列通常由于采集范围大、时间间隔长带有一定震荡性和模糊性,这使得对其进行分析与预测有一定的难度。本研究中以某近海水质指标磷酸盐(PO3-4-P)、硝酸盐(NO-3-N)、亚硝酸盐(NO-2-N)、铵盐(TNH+4-N)和硅酸盐(Si O2-3-Si)所形成的5种时间序列为例,采用逼近细分模式导出的细分外推法和多参考加权数据的模糊预测法对近海水质时序预测进行了比较分析,并通过图形与误差计算比较了两种方法的异同。结果表明:采用细分外推法预测序列在整体形状上能更好地逼近初始时序,而模糊预测法在整体逼近精度上占有优势。本研究中提出的预测比较方法可为同类问题的预测与模型选取提供参考依据。     

Stock structure of blue threadfin Eleutheronema tetradactylum across northern Australia as inferred from stable isotopes in sagittal otolith carbonate

Abstract Stable isotopes of δ¹⁸O and δ¹³C in sagittal otolith carbonates were used to determine the stock structure of the polynemid Eleutheronema tetradactylum (Shaw) across tropical northern Australia, where this species is an important component of inshore commercial and recreational fisheries. Stable isotopes from the sagittal otolith carbonate of 470 fish from 11 discrete locations across western, northern and eastern Australia were sampled between 2007 and 2009. Analysis of these stable isotopes revealed different location‐specific signatures, indicating strong population subdivision. The significant differences in the isotopic signatures of E. tetradactylum demonstrated that there is unlikely to be substantial movement of fish between these locations. The spatial separation of these populations indicates a complex fine spatial scale stock structure across northern Australia, with at least 11 stocks or management units present. The population subdivision of E. tetradactylum was evident along expansive stretches of open beach systems and within coastal embayments with no physical barriers such as headlands. These results indicate that optimal fisheries management will require a review of the current spatial arrangements, particularly the potential for localised depletion of stocks on small spatial scales.     

深厚覆盖层上高心墙堆石坝坝顶开裂特征及原因研究

国内多座深厚覆盖层上兴建的高心墙土石坝坝顶均出现不同程度的开裂,对坝体的长期安全稳定构成威胁,受到业内广泛关注。通过地质雷达、高密度电法等物探技术确定某高心墙堆石坝顶裂缝时空分布情况,根据变形实测资料分析了其变形破坏特征,并结合工程建设情况、结构特征、运行情况等对开裂原因进行分析。结果表明坝顶裂缝产生的根本原因是土体承受的应力超过其抗拉强度或抗剪强度后而发生的破坏,直接原因为坝顶的不均匀沉降,其中水荷载、湿化变形、蓄水速度、坝顶材料特性是坝顶不均匀沉降的关键影响因素。     

Loop细分技术在犁体曲面造型中的应用

阐述了细分方法的基本思想以及基于三角网格的Loop细分模式的原理和方法；提出了在相关几何造型、有限元分析和动态仿真软件配合下，基于OpenGL环境或CAD二次开发环境的复杂犁体曲面造型的细分方案；对犁体曲面的控制网格生成、边界限定等关键技术进行了讨论。利用该方法可以有效缩短复杂犁体曲面的造型、计算和分析时间。     

RECREATING SMALL SEAMLESS TUBE MILLS BY PIERCING INSFEAD OF ROLLING

This paper discuss the effects of automatic plug mills in small seamless tube mills. Far from traditional ideas,the auther comes rp with mew ideas, which adot the mew process of replacing rolling by piercing,a huge sum of economical interests and great social benefits will be gained.     

武汉军山长江大桥非线性地震反应时程分析

以武汉军山长江大桥为例，分析了斜拉桥的动力特性以及在一致激励和非一致激励下的非线性地震反应，并进行了减、隔震研究.结果表明：1）该桥基本周期很长，约为8.881 s，其第一振型为纵飘振型.2）几何非线性对其地震反应影响明显.3）同时考虑三个方向的地震波作用时，非一致激励对主梁和塔抗震设计不利.4）将普通支座更换为铅芯橡胶支座、粘弹性阻尼器，或两种减震装置同时使用时，减震效果明显.从减震效果比较，可以优先采用高阻尼铅芯橡胶支座+粘弹性阻尼器的做法.     

基于非均匀B样条小波的服装纸样优化识别方法及应用

针对服装样片纸样的形状与结构特点，提出一种由曲率确定型值点分布的非均匀B样条曲线拟合识别方法，并用其样条小波进行型值点压缩和优化，以达到在给定误差下型值点数目尽量少的目的．通过分析比较和实例检验表明，这种算法识别服装纸样方便可靠，为服装计算机辅助设计(CAD)中样片的编辑设计提供一种智能高效的输入技术．     

关于非一致收敛的几个定理

本文给出了非一致性收敛的几个定理，并以较多的实例说明它们的应用。     

江西省毛竹栽培区划及立地类型划分的研究

毛竹是江西省重要的经济树种,全省现有毛竹林面积793.7万亩,蓄积95737万根,毛竹生产在全省的林业生产中占有相当重要的地位。本文遵照自然规律和经济规律,以气候、地形和土壤等自然因子为主要依据,同时参照毛竹原有分布数量及社会经济状况,把江西省划分为5个毛竹栽培区。并根据立地因子的差异,应用逐步回归分析方法,寻求出主导因子,把江西省毛竹栽培区内划分出27个不同的立地类型。     

Effect of road density on abundance of white-footed mice

While several studies have demonstrated that roads can act as barriers to small mammal movement, the relationship between road density and small mammal abundance has not yet been investigated. In southeastern Ontario, Peromyscus leucopus (white-footed mice) suffer high over-winter mortality rates, resulting in small springtime populations and frequent local extinctions. Peromyscus leucopus movement is known to be inhibited by roads, which should result in lower rates of immigration into and recolonization of habitats in landscapes with high road density. We tested two predictions: (1) Forest sites situated in landscapes with high road densities have a higher chance of P. leucopus being absent during the early spring than forest sites situated in landscapes with low road densities and (2) P. leucopus populations during the summer are smaller in forest sites situated in landscapes with high road densities than in landscapes with low road densities. We sampled P. leucopus in focal patches within nineteen landscapes (7 rural, low-road-density landscapes; 7 rural, high-road-density landscapes; 5 urban landscapes). There was no significant relationship between road density and the presence/absence of P. leucopus during the early spring. We found a significant positive effect of road density on P. leucopus relative abundance during the summer, even when we excluded the urban landscapes and based the analysis on only the 14 rural landscapes. Our results suggest that any negative effect of roads on P. leucopus populations, created by their inhibition to moving across roads, is far outweighed by some positive effect of roads on P. leucopus abundance. We suggest that the two most likely explanations are that roads are positively correlated with an important as-yet-undetermined component of habitat quality, or that roads positively affect P. leucopus by negatively affecting their predators.