670 resultados para 1340-1416
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用动态光散射方法研究了酚酞型聚醚砜(PES—C)在良溶剂DMF中的稀溶液性质。在稀溶液中,PES—C分子由于内旋转发生链折叠,整体上表现出柔性链的性质,较好的符合球形模型;而分子链的局部刚性结构又使分子尺寸稳定;它的扩散行为随温度的变化符合Arrehnius方程。表征了PES—C分子在稀溶液中的形态结构,且给出了PES—C分子在DMF中的扩散系数、扩散活化能、无限稀时的扩散系数和流体力学半径等重要特征参数。
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2007年夏季对黄海冷水团及邻近海域共48个站位的小型底栖动物组成、丰度和生物量,以及环境因子进行了科考研究。所调查站位的小型底栖动物平均丰度达2194 ± 1598 inds./10cm2,其中北黄海17个站位平均丰度为3408 ± 1578 inds./10cm2,南黄海31个站位平均丰度为1529 ± 1121 inds./10cm2。调查站位平均生物量为1839 ± 1289 g dwt/10cm2,其中北黄海站位平均生物量为2760 ± 1340g dwt/10cm2,南黄海平均生物量为1335 ± 902g dwt/10cm2。在分选出的共18个小型底栖动物类群中,丰度上均以自由生线虫占绝对优势,达总量的88%,且在南(88.3%)、北黄海(87.7%)基本无差异。在生物量上,同样以自由生线虫贡献最多(42%),多毛类居次(22%),其他生物量较多的还有桡足类(13%)和甲壳类幼体(12%)。在小型底栖动物的垂直分布上,分布于沉积物表层0-2cm的小型底栖动物占79%,次表层2-5cm占17%,最底层5-8cm仅占4%。统计分析表明研究站位小型底栖动物丰度和生物量与沉积物叶绿素a、有机质含量、中值粒径显著或极显著正相关,与水深呈极显著负相关,此外小型底栖动物生物量与沉积物粉砂粘土含量显著负相关。 同年秋季搭载开放航次对黄海5个站位、东海3个站位、南海2个站位的小型底栖动物组成、丰度和生物量,以及环境因子进行了调查研究。对三个海域小型底栖动物的比较研究发现,平均丰度以黄海最高,达2132 ± 946 inds./10cm2,东海次之,为1954 ± 2047 inds./10cm2,而南海仅156 ± 56 inds./10cm2;三海域的平均生物量依次为2193 ± 1148 g dwt/10cm2、1865 ± 1555 g dwt/10cm2和212 ± 22 g dwt/10cm2。在分选出的共14个小型底栖动物类群中,丰度上均以自由生线虫占绝对优势,分别占总量的85%、89%、85%。在生物量上,黄海以自由生线虫贡献最多(33%),多毛类居次(18%);东海二者比例相近(约37%),而南海则以多毛类占绝对优势(56%),线虫居次(25%)。在小型底栖动物的垂直分布上,三个海区差异较大:分布于沉积物表层0-2cm的小型底栖动物在黄海高达90%,东海仅46%,在南海为63%。统计分析表明,本研究站位小型底栖动物丰度与沉积物中的叶绿素a及脱镁叶绿素a含量和底温呈显著正相关,与水深呈显著负相关。该结果与本航次之后在广东湛江和海南以东的南海海域开展的908调查结果形成了鲜明对照,后者的小型底栖动物及线虫丰度与沉积物中有机质含量呈显著正相关,与水深呈显著负相关,表明近海受人类干扰影响较大。 本文利用微宇宙实验方法,来确定不同浓度梯度的Cu、Pb以及Cu/ Pb混合重金属污染物对青岛湾小型底栖动物(主要是线虫)的影响。加入污染物后,分别在1、3、7、14、21天进行取样分析。结果显示,Cu和Cu/Pb混合高浓度实验单元组的线虫丰度除在第21天有较明显减少外,在整个实验周期内基本没有变化,分析可能系高浓度Cu的固定作用从而使小型底栖动物无法腐烂降解造成的。同一时间尺度上,各重金属污染物实验单元的线虫丰度均高于(或接近于)空白对照组,较高浓度的重金属污染物实验单元的线虫丰度高于(或接近于)较低浓度重金属污染物实验单元,Cu/Pb混合低浓度实验单元的线虫丰度高于同一时间尺度Cu低浓度和Pb低浓度实验单元。推测是由于采样点的线虫群落中存在对Cu和Pb的耐受种或者“机会种”造成的。
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黑潮是西北太平洋一支高温、高盐、高流速的西边界流,它起源于菲律宾以东海域,沿吕宋岛、台湾东岸、东海大陆架外缘流动,并穿越吐噶喇海峡返回太平洋。其中吕宋岛至台湾岛这段西边界流命名为源区黑潮。源区黑潮在流经吕宋海峡以东时,由于失去岸界支撑会发生形变,并通过吕宋海峡与南海环流体系进行质量、动量和能量的交换,并影响着南海的环流特征。因此研究黑潮通过吕宋海峡入侵南海的关键动力过程和机制,对我们国家的军事、生产、环境等具有十分重大的意义,一直是国内外海洋学家关注的焦点。 本文利用高度计资料和涡旋精度的高分辨率数值模式(OFES)输出结果分析了南海东北部和吕宋海峡东侧海域的上层环流特征,并独立建立1.5层浅水约化重力模式下的理想模型,分析了黑潮从吕宋海峡入侵南海的非线性特征和西传的大洋中尺度涡旋与黑潮在吕宋海峡处的相互作用。 对高度计资料和模式结果资料分析的结果表明季风是影响南海北部上层环流的主要因素,黑潮以各种方式入侵南海也是影响南海北部环流特征的重要组成部分。通过数值模拟,我们得到在不同的参数下,黑潮入侵南海会存在稳定态、分叉、周期解等非线性特征,对应着黑潮南海流套、分离流环、无入侵等多种流态。通过讨论大洋中尺度涡旋与黑潮在吕宋海峡处的相互作用,发现涡旋在西传遇到黑潮后基本局地耗散或随黑潮继续向北移动,但当黑潮较弱时,涡旋可能将大洋中的能量通过吕宋海峡传入南海。
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本文围绕非线性海洋波动理论分别从三个方面作了研究。第一,非线性定形波的研究。采用微分方程的几何理论与动力学相结合的方法,将控制地球流体的运动方程,通过行波变换,作为平面自治系统,利用相图理论,分别分析了非线性惯性重力波、非线性Rossby 波等的定性性质,得到了惯性重力波不存在定形孤波解的结论;通过对平面自治系统在平衡点处作Taylor展开,结合K-B平均法,求得了带有刻划非线性效应小参数的非线性频散关;论证了分式简谐函数为地球流体中有限振幅波解的一般形式。第二,非线性水波时空变化规律的研究,利用水波的变分方程,在行波或空间上进行Galerkin截谱,分离时空变量,并计及非线性效应的二次项,分别导出了水波随时间、空间的变化规律。其中,浅水非笥性波随时、空的变化规律满足用来描述非线性振动现象的Duffing方程,这使得Duffing方程在非线性水波的研究领域也找到了应用背。众所财拓KdV理论是水波的非线性效应和色散效应平衡的产物,在此尺度下,波形随时、空的变化不能被揭示出来。因此,本文所得到的结果是KdV理论和调制波理论的补充和发展。而且,这些结果便于实际应用。第三,非线性随机海浪统计分布的研研。基于动力学原理,研究了非线性波振动和位相的分布规律。利用我们所得到的波形随时间的演化过程,将随机输入看作初值,用渐近方法得到带有随机项的非线性水波的振幅和位相,从而建立了符合动力学原理的非线性波振幅和位相的概率分布,将将其和传统的结论以及测资料作了比较,结果表明,吻合较好。这种尝试性的方法在该领域的应用尚属首次,可望能够成为研究非性线随机波的一种手段。
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Although respiration of organisms and biomass as well as fossil fuel burning industrial production are identified as the major sources, the CO2 flux is still unclear due to the lack of proper measurements. A mass-balance approach that exploits differences in the carbon isotopic signature (delta(13)C) of CO2 Sources and sinks was introduced and may provide a means of reducing uncertainties in the atmospheric budget. delta(13)C measurements of atmospheric CO2 yielded an average of - 10.3 parts per thousand relative to the Peedee Belemnite standard; soil and plants had a narrow range from -25.09 parts per thousand to -26.51 parts per thousand and averaged at -25.80 parts per thousand. Based on the fact of steady fractionation and enrichment during respiration of mitochondria, we obtained the emission Of CO2 of 35.451 mol m(-2) a(-1) and CO2 flux of 0.2149 mu mol m(-2) s(-)1. The positive CO2 flux indicated the Haibei Alpine Meadow Ecosystem a source rather than a sink. The mass-balance model can be applied for other ecosystem even global carbon cycles because it neglects the complicated process of carbon metabolism, however just focuses on stable carbon isotopic compositions in any of compartments of carbon sources and sinks. (C) 2005 Elsevier B.V. All rights reserved.
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Floral organogenesis and development of two Solanaceae species, Anisodus tanguticus and Atropa belladonna, were studied by using scanning electron microscopy (SEM) as part of a project on systematics and evolution in the tribe Hyoscyameae. These two species share the following common characters of floral organ initiation and development: (1) initiation of the floral organs in the two species follows Hofmeister's rule; (2) the mode of corolla tube development belongs to the "late sympetaly" type, namely, petals are initiated separately and later become joined by fusion of their basal meristem, then rise together and form a corolla tube; (3) primordia of the floral appendages are initiated in a pentamerous pattern and acropetal order: sepals are initiated first, followed by the petals and stamens, and finally the carpels. The whorl of five stamen primordia forms almost simultaneously and originates opposite the sepal primordia, but initiation of the sepal primordia shows different modes in the two species. The sepal primordia of Anisodus tanguticus have simultaneously whorled initiation, while those of Atropa belladonna have helical initiation. The systematic significance of the present results in the genera Anisodus and Atropa is discussed in this paper.
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针对混装配线设计这一有约束的多目标优化问题,建立了数学模型。将基于Pareto的解的分级方法与Lp-范数形式的非线性机制相组合,构建了基于遗传退火算法多目标优化方法。重点阐述了个体编码、染色体检修、多目标处理机制等关键技术。设计了算法流程图,并开发了优化程序。该方法克服了加权和方法的不足,用模拟退火改善了遗传算法全局寻优性能。计算实例表明,随着迭代次数的增加,每代的非受控点逐渐收敛于Pareto最优边界,是一种混装线设计多目标优化的新方法。
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Conventional 3D seismic exploration cannot meet the demand of high yield and high efficiency safe production in coal mine any more. Now it is urgent to improve the discovery degree of coal mine geological structures for coal production in China. Based on 3D3C seismic exploration data, multi-component seismic information is fully excavated. First systematic research on 3D3C seismic data interpretation of coal measure strata is carried out. Firstly, by analyzing the coal measure strata, the seismic-geologic model of coal measure strata is built. Shear wave logging is built by using regression analysis. Horizon calibration methods of PP-wave and PS-wave are studied and the multi-wave data are used together to interpret small faults. Using main amplitude analysis technology, small faults which cannot be found from PP-wave sections can be interpreted from the low frequency PS-wave sections. Thus, the purpose to applying PS-wave data to fine structure assistant interpretation is achieved. Secondly, PP- and PS-wave post-stack well constrained inversion methods of coal measure strata are studied. Joint PP- and PS-wave post-stack inversion flow is established. More attribute parameters, which are applied in fine lithology interpretation of coal measure strata, are obtained from combinations of the inversion results. Exploring the relation between rock with negative Poisson’s ratio and anisotropy, fracture development in coal seam are predicted. Petrophysical features of coal measure strata are studied, and the relations between elastic parameters and lithology, fluid and physical properties are established. Inversions of the physical parameters such as porosity, permeability and water saturation, which reflect lithology and fluid property, are obtained. Finally, the approaches of shear wave splitting and Thomsen parameters inversion, which provide new ideas for seismic anisotropy interpretation of coal measure strata, are studied to predict fracture development. The results of practical application indicate that the methods in this paper have good feasibility and applicability. They have positive significance for high yield and high efficiency safe production in coal mine.
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China is a mountainous country in which geological hazards occurred frequently, especially in the east of China. Except the geology, topography and extreme climate, the large scale human activities have become a major factor to landslides. Typical human activities which induced landslides are fill, cut and underground mining. On the topic of the deformation mechanism and slope stability, taking three different man-made slopes as examples, deformation mechanism and slope stability were studied by several methods, such as field work, numerical modeling and monitor. The details are as following: (1) The numerical modeling approach advantages over other conventional methods such as limit methods, so the numerical modeling is the major tool in this thesis. So far, there is no uniform failure criterion for numerical simulation. The failure criterion were summarized and analyzed firstly, subsequently the appropriate criterion was determinated. (2) Taking 220kV Yanjin transformation substation fill slope as example, the deformable characteristic, unstable mode and laboratory tests were studied systematically. The results show: the slope deformation was probably caused by a combination effect of unfavorable topographic, geological and hydro geological conditions, and external loading due to filling. It was concluded that the creep deformation of the slope was triggered by external loading applied at the back of the slope. In order to define the calculating parameters, a set of consolidated drained (CD) tests, consolidated undrained (CU) tests, repeated direct shear tests and UCS tests were carried out. The stability of the slope before and after reinforcement was assessed using 3D numerical modeling and shear strength reduction technique. The numerical modeling results showed: the factor of safety (FOS) of the slope was 1.10 in the natural state, and reduced to 1.03 after fill, which was close to the critical state and it caused creeping slip or deformation under rainfall. The failure surface in the slope is in active shear failure, whereas tensile failure occurs at the slope crest. After the site was reinforced with piles, the FOS was 1.27. Therefore, the slope is stable after reinforcement measures were taken. (3) The cut slope stability is a complex problem. Taking the left cut slope of Xiangjiaba as example in this thesis, the deformation and slope stability were studied systematically by numerical modeling and monitor methods. The numerical results show: the displacement is gradually increasing along with the cutting, and the largest displacement is 27.5mm which located at the bench between the elevation 340 and 380. Some failure state units distribute near the undermining part and there is no linked failure state occurred from crest to bottom during cutting. After cutting, some failure units appeared at the ground surface between elevation 340 and 360. The increasing tense stress made the disturbed rock failed. The slope is stable after cutting by the monitor method, such as surface monitor, multipoint displacement meter, inclinometer and anchor cable tensometer. (4) The interaction between underground mining and slope stability is a common situation in mountainous. The slope deformation mechanism induced by underground mining may contributed significantly to slope destabilization. The Mabukan slope in xiangjiaba was analyzed to illustrate this. Failure mechanism and the slope stability were presented by numerical modeling and residual deformation monitor. The results show: the roof deformed to the free face and the floor uplift lightly to the free face. The subsidence basin is formed, but the subsidence and the horizontal movement is small, and there is no failure zone occurred. When the underground mining is going on, the roof deformation, subsidence and the horizontal movements begin increasing. The rock deformation near the free face is larger than the ground surface, and the interaction between these coal seams appeared. There are some tensile failures and shear failures occurred on the roof and floor, and a majority of failure is tensile failure. The roof deformation, subsidence and the horizontal movements increased obviously along with the underground mining. The failure characteristic is shear failure which means the tensile stress transformed to the compressive stress. So the underground mining will induced tensile stress first which lead to structure crack, subsequently the compressive stress appeared which result in slippage. The crest was subjected to horizontal tension which made the rock crack along with the joint. The long term residual deformation monitor demonstrates that the slope is stable after the underground mining stopped.
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月表太阳辐射是深入研究月表温度分布的关键问题之一.本文根据月表有效太阳辐照度与太阳常数、太阳辐射入射角以及日月距离之间的关系,建立月表有效太阳辐照度的实时模型.该模型在1950-2050年的100年内的理论误差百分比小于0.28%,相对前人提出的模型在精度上有了很大程度的提高,能较为真实地反映月表有效太阳辐照度随时间的变化规律.计算结果表明2007年月表太阳辐照度的年变化范围在1321.5-1416.6 W·m^-2之间,平均为1368.0 W·m^-2.通过对月表太阳辐射入射角计算结果的分析,证实了月球的两极可能存在极昼极夜.
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利用被动微波遥感亮度温度数据反演月壤厚度是“嫦娥”探月工程的科学目标之一,也是人类探测月壤厚度的一种新的尝试。深入研究月表太阳辐射、月球内部热流以及月表温度的分布和变化规律,是解译遥感数据,反演月壤厚度的前提条件,也为进一步开展月球探测、开发利用月球资源乃至建立月球基地相关研究工作提供必要的参考。 本文根据月表有效太阳辐照度与太阳常数、日月距离和太阳辐射入射角的关系,建立了月表有效太阳辐照度的实时模型如下: (1) 其中, (2) (3) 通过对月表有效太阳辐照度实时模型的各个参数分析发现,影响月表有效太阳辐照度变化的主要因素是日地距离和太阳辐射入射角的变化。对模型的误差分析表明,从1950年到2050年的100年内,月表有效太阳辐照度计算结果的误差百分比小于0.28%,能更准确地反映月表有效太阳辐照度的变化情况。从2007年月表有效太阳辐照度的计算结果发现,该年内的月表有效太阳辐照度变化在1321.5~1416.6 W•m-2之间,平均为1368.0 W•m-2,一个月内的变化最小幅度为6.0 W•m-2,最大幅度为23.6 W•m-2。 在月表有效太阳辐照度的实时模型基础上,根据能量守恒和Stefan-Boltzmann定律,本文还得出了月表温度分布模型如下: (4) 其中,初始条件由下式决定, (5) 通过与月表温度实际观测结果的比较发现,当月表反射率、热发射率和热惯量分别取0.127、0.94和125 J•m-2•s-1/2•K-1时,模型的计算结果与实际观测值比较符合,能较好地预测理想条件下的月表温度。 月表热参数研究的一个重要应用就是解译对月被动微波遥感的亮度温度数据。在对月被动微波遥感探测中,辐射计获得的亮度温度反映了月球表层的热辐射特性。月球表层的热辐射与其自身的热状况紧密相关,结合文中建立的月表热参数模型,根据辐射传播理论进一步分析了对月微波遥感探测中,月球表层在不同情况下对亮度温度的贡献,确定了亮度温度随月表温度和月壤厚度的变化关系,对被动微波遥感探测月壤厚度的可能性和可能达到的精度进行了估算。 对月球表层的热辐射传播的分析发现,对月被动微波遥感探测获得的亮度温度受月球表层热辐射的控制,与月壤厚度具有指数相关性,并受到月表温度的影响。当月壤和月岩的复介电常数分别为2 + 0.005 j和9 + 1 j、相对磁导率均为1时,对应3.0GHz、7.8GHz、19.35GHz和37.0GHz四个频率的亮度温度与月壤厚度及月表温度的关系可分别近似表示为, 3.0GHz亮度温度: (6) 7.8GHz亮度温度: (7) 19.35GHz亮度温度: (8) 37.0GHz亮度温度: (9) 当月壤厚度和月表温度分别在0.5m~30m和100K~400K之间变化时,上述四个频率的亮度温度变化范围分别在212.5K~252.8K、207.4 K~266.7K、193.8 K~288.6K和174.0 K~310.9K之间。对于较低频率的被动微波遥感,亮度温度随月壤厚度的增大逐渐增大并趋于稳定;对较高频率的被动微波遥感,亮度温度随月壤厚度的增大会产生起伏波动,不利于用单波段反演月壤厚度。亮度温度梯度在频率较高时梯度较大,在很小的月壤厚度范围内很快就趋于0,不利于厚度较大时的月壤厚度反演,但对于厚度较小时的月壤厚度反演精度较高;同时,除3.0GHz外,7.8GHz、19.35GHz和37.0GHz三个频率的亮度温度梯度随月表温度的升高降幅较大,尤其是19.35GHz,适合在夜间对月壤厚度较小的地区进行更精确的探测。对于3.0GHz,其亮度温度梯度受月表温度变化的影响很小,能反映出较深层月壤厚度的信息,可以对月球进行全球全天时探测。若辐射计的分辨率为0.02K,3.0GHz频率对10m厚月壤的判别精度达到0.07m;对于20m厚月壤的精度为1.4m。当月壤厚度小于0.5m时,随着月壤厚度从0到0.5m增加,月球表层的亮度温度贡献呈先减小后增大的趋势,从而使某一亮度温度值可能对应存在两种不同的月壤厚度。因此,对于月壤厚度小于0.5m的区域,利用单波段被动微波遥感亮度温度反演月壤厚度是比较困难的。 在对月被动微波遥感探测中,可以利用月球夜晚时段的亮度温度数据判别月壤厚度是否小于0.5m。当月表温度为100K时,3.0GHz、7.8GHz、19.35GHz和37.0GHz四个频率的亮度温度判别参考值分别为212.9K、207.4K、193.5K和174.1K;月表温度为240K时,上述四个频率的亮度温度判别参考值分别为220.8K、226.8K、234.1K和237.2K。当亮度温度小于参考值时表示月壤厚度小于0.5m,反之,表示月壤厚度大于0.5m。更进一步地,可以根据月表温度的影响系数对月岩是否裸露于月表进行判断。当3.0GHz、7.8GHz、19.35GHz和37.0GHz四个频率的月表温度影响系数接近0.77、0.82、0.84和0.85时,可以认为月岩直接暴露于月表。
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We discuss a strategy for visual recognition by forming groups of salient image features, and then using these groups to index into a data base to find all of the matching groups of model features. We discuss the most space efficient possible method of representing 3-D models for indexing from 2-D data, and show how to account for sensing error when indexing. We also present a convex grouping method that is robust and efficient, both theoretically and in practice. Finally, we combine these modules into a complete recognition system, and test its performance on many real images.
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RESUMO: O objetivo deste trabalho foi avaliar características agronômicos durante o desenvolvimento de híbridos de girassol cultivados na região de Campo Novo do Parecis - MT. O ensaio foi instalado e conduzido,entre os meses de fevereiro ejunho de 2015, na área experimental do setor de produção do Instituto Federal de Educação, Ciência e Tecnologia de Mato Grosso - IFMT Campus Campo Novo do Parecis - MT, cujas coordenadas geográficas são latitude S 13°40'31" longitude O 57°53'31" e altitude média de 574 m. O solo predominante é Latossolo Vermelho distrófico típico. O delineamento experimental foi em blocos casualizados com 13 tratamentos (híbridos) e 4 repetições, totalizando um total de 52 parcelas. Foram avaliadas as seguintes características agronômicas do girassol: dias para o florescimento inicial, dias para a maturação fisiológica, altura de planta, curvatura do caule, número de plantas acamadas, número de plantas quebradas e produtividade de aquênios. Os dados foram submetidos à análise de variância e ao teste de média Scott-Knott (p<0,05). O híbrido BRS G44 apresentou híbrido BRS G44 apresentou bom rendimento, ciclo precoce e porte baixo, nas condições de segunda safra de verão em Campo Novo do Parecis (MT) . Assim, este híbrido se torna boa opção para o cultivo de girassol na região. ABSTRACT: The objective of this study was to evaluate agronomic characteristics for the development of sunflower hybrids grown in the region of Campo Novo do Parecis - MT. The experiment was carried out and conducted between the months of February to June 2015 in the experimental area of the production sector of the Instituto Federal de Educação, Ciência e Tecnologia de Mato Grosso, - IFMT, Campo Novo do Parecis - MT (latitude S 13°40'31" longitude W 57°53'31" and average altitude of 574 m). The predominant soil is Typic Tropudox. The experimental design was randomized blocks with 13 treatments (hybrids) and four repetitions, resulting in 52 plots. The sunflower agronomic traits evaluated were: days to initial flowering, days to physiological maturity, plant height, stem curvature, number of lodged plants, number of broken plants and achenes productivity. Data were subjected to analysis of variance and average test Scott-Knott (p<0.05). The hybrid BRS G44 showed good yield, early maturity and low height in second summer crop conditions in Campo Novo do Parecis (MT). Thus, this hybrid is a good option for sunflower cultivation in the region.
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Pearson, Mike, Shanks, Michael, Theatre/Archaeology (London: Routledge, 2001), pp.xviii+215 RAE2008
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Dennis, P., Aspinall, R. J., Gordon, I. J. (2002). Spatial distribution of upland beetles in relation to landform vegetation and grazing management. Basic and Applied Ecology, 3 (2), 183?193. Sponsorship: SEERAD RAE2008