996 resultados para 205-1254
Resumo:
Sixteen polycyclic aromatic hydrocarbons (PAHs) and 28 polychlorinated biphenyls (PCBs) were measured at a 2-cm interval in a core sample from the middle of the southern Yellow Sea for elucidating their historical variations in inflow and sources. The chronology was obtained using the Pb-210 method. PAHs concentrations decreased generally with depth and two climax values occurred in 14-16 cm and 20-22 cm layers, demonstrating that the production and usage of PAHs might reach peaks in the periods of 1956-1962 and 1938-1944. The booming economy and the navy battles of the Second World War might explain why the higher levels were detected in the two layers. The result of principal component analysis (PCA) revealed that PAHs were primarily owing to the combustion product. Down-cored variation of PCB concentrations was complex. Higher concentrations besides the two peaks being the same as PAHs were detected from 4 to 8 cm, depositing from 1980 to 1992, which probably resulted from the disposal of the out-dated PCB-containing equipment. The average Cl percentage of PCBs detected was similar to that of the mixture of Aroclor 1254 and 1242, suggesting they might origin from the dielectrical and heat-transfer fluid. The total organic carbon (TOC) content played a prevalent role in the adsorption of high molecular weight PAHs (>= 4-ring), while no obvious relationship among total PCBs, the concentration of congeners, and TOC was found.
Resumo:
Survival, growth and immune response of the scallop, Chlamys farreri, cultured in lantern nets at five different depths (2, 5, 10, 15, and 20 m below the sea surface) were studied in Haizhou Bay during the hot season (summer and autumn) of 2007. Survival and growth rates were quantified bimonthly. Immune activities in hemolymph (superoxide dismutase (SOD) and acid phosphatase (ACP)) were measured to evaluate the health of scallops at the end of the study. Environmental parameters at the five depths were also monitored during the experiment. Mortalities mainly occurred during summer. Survival of scallops suspended at 15 m (78.0%) and 20 m (86.7%) was significantly higher than at 2 m (62.9%), 5 m (60.8%) or 10 m (66.8%) at the end of the study. Mean shell height grew significantly faster at 10 m (205.0 mu m/d) and 20 m (236.9 mu m/d) than at 2, 5 or 15 m in summer (July 9 to September 1); however, shell growth rate at 20 m was significantly lower than at the other four depths in autumn (September 2 to November 6). In contrast to summer, scallops at 5 m grew faster (262.9 mu m/d) during autumn. The growth of soft tissue at different depths showed a similar trend to the shell. Growth rates of shell height and soft tissue were faster in autumn than in summer, with the exception of shell height at 20 m. SOD activity of scallops increased with depth, and ACP activity was significantly higher at 15 and 20 m than at other depths, which suggests that scallops were healthier near the bottom. Factors explaining the depth-related mortality and growth of scallops are also discussed. We conclude that the mass mortality of scallop, C. farreri, during summer can be prevented by moving the culture area to deeper water and yield can be maximized by suspending the scallops in deep water during summer and then transferring them to shallow water in autumn.
Resumo:
以1-(2-萘基)-3-甲基-5-吡唑啉酮(NMP)作为柱前衍生试剂,建立了简单、灵敏的糖类组分的反相高效液相色谱测定方法。NMP与糖在氨为催化剂的条件下,于70℃下反应可获得稳定的衍生产物。在HypersilODS2反相色谱柱上,实现了8种单糖的基线分离。衍生物线性相关系数均大于0.9985,检出限为0.58-1.1pmol。利用柱后在线串联质谱的电喷雾电离正离子模式监测,获得了各组分的质谱定性及裂解规律,特别是m/z473的特征碎片离子可作为单糖NMP衍生物的判定依据。与1-苯基-3-甲基-5-吡唑啉酮(PMP)相比,NMP对糖的衍生化具有灵敏、简单、质谱裂解规律性强、重现性好等优点。该方法用于测定油菜花粉多糖中的单糖组成,结果令人满意。
Resumo:
以海北高寒草甸生态系统定位站的涡度相关系统连续观测的CO_2通量数据为基础,分析了青藏高原的高寒矮嵩草(Kobresia humilis)草甸、高寒金露梅(Potentilla fruticosa)灌丛草甸和高寒藏嵩草(Kobresia tibetica)沼泽化草甸等3种主要植被类型在2005年植物生长季(6-9月)的表观量子产额(a)、最大光合速率(Pmax)和呼吸速率(Reco)的变化特征.结果表明:3种植被类型白天的净生态系统CO_2交换量(NEE)和光量子通量密度(PPFD)存在明显的直角双曲线关系(P<0.05),其a、Pmax和Reco呈现出相似的季节变化趋势,在生长季初期(6月)最小,在7月或8月份达到最大;高寒矮嵩草草甸的a、Pmax和Reco大于灌丛草甸和沼泽化草甸,而后两者差别不大.
Resumo:
为了解青海省春小麦收割后田间堆放期间产量和品质的变化,选择近年育成的春小麦品种“高原205”(白粒,易穗发芽)、“高原115”(紫黑色小麦)、“高原448”(红粒)和“高原314”(白粒)以及曾为青海省主栽品种的“青春533”(红粒)为材料,收割后以农民常用的田间堆放方式进行堆放,每隔9d对其进行采样,测定产量、SDS沉淀值和降落数值的变化。结果表明,随着堆放时间的延长,收获产量逐步下降,平均产量从第1次采样(Od)时的504g/m^2减少到63d后的384g/m^2,收获产量平均值与取样时间直线回归F值为20.91,大于F0.01(6.90);SDS沉淀值变化较小,F值为0.90,小于F0.05(2.13);降落数值在取样时间点上差异极显著.F值等于46,72,大于F0.01(2.87)。高原205的降落数值一直呈现下降趋势,而高原448、高原115、高原314和青春533的变化是在O~18d间上升,然后下降。总体而言,田间堆放对收获产量和品质不利。
Resumo:
Potentilla fruticosa scrub, Kobresia humilis meadow and Kobresia tibetica meadow are widely distributed on the Qinghai-Tibet Plateau. During the grass exuberance period from 3 July to 4September, based on close chamber-GC method, a study on CO2 emissions from different treatments was conducted in these meadows at Haibei research station, CAS. Results indicated that mean CO2emission rates from various treatments were 672.09+152.37 mgm-2h-1 for FC (grass treatment); 425.41+191.99 mgrn-2h-1 for FJ (grass exclusion treatment); 280.36+174.83 mgrn-2h-1 for FL (grass and roots exclusion treatment); 838.95+237.02 mgm-2h-1 for GG (scrub+grass treatment); 528.48+205.67 mgm-2h-1for GC (grass treatment); 268.97 ±99.72 mgm-2h-1 for GL (grass and roots exclusion treatment); and 659.20±94.83 mgm-2h-1 for LC (grass treatment), respectively (FC, FJ, FL, GG, GC, GL, LC were the Chinese abbreviation for various treatments). Furthermore, Kobresia humilis meadow, Potentilla fruticosa scrub meadow and Kobresia tibetica meadow differed greatly in average CO2 emission rate of soil-plant system, in the order of GG>FC>LC>GC. Moreover, in Kobresia humilis meadow,heterotrophic and autotrophic respiration accounted for 42% and 58% of the total respiration of soil-plant system respectively, whereas, in Potentilla fruticosa scrub meadow, heterotrophic and autotrophic respiration accounted for 32% and 68% of total system respiration from G-G; 49% and 51%from GC. In addition, root respiration from Kobresia humilis meadow approximated 145 mgCO2m-2h-1,contributed 34% to soil respiration. During the experiment period, Kobresia humilis meadow and Potentilla fruticosa scrub meadow had a net carbon fixation of 111.11 grn-2 and 243.89 grn-2,respectively. Results also showed that soil temperature was the main factor which influenced CO2 emission from alpine meadow ecosystem, significant correlations were found between soil temperature at 5 cm depth and CO2 emission from GG, GC, FC and FJ treatments. In addition, soil moisture may be the inhibitory factor of CO2 emission from Kobresia tibetica meadow, and more detailed analyses should be done in further research.
Resumo:
湟水流域位于青海省的东部,约处于北纬35°56′-37°38′,东径100°35′-103°05′。属于青藏高原和黄土高原的过滤地带,海拔1650-4394m,全区面积约16600km^2,属于大陆性气候和高原大陆性气候类型。本区共有野生种子植物83科、400属、1234种。分别占本区所属的青藏高原植物亚区唐古特地区总科数的92.22%、总属数的78.74%、总种数的54.00%。研究表明,湟水流域植物区系特征为:(1)在唐古特地区中种类相对较丰富;(2)温带成分占2.80%,以绝对优势确定了本区系为明显的温带性质(属于以北温带成分,特别是欧亚大陆温、寒地带典型成分为优势的,兼具温性,寒温和高寒类型的温带区系性南,或可称为在温带区第中的过渡区系所具有的“复合型”区系特征);(3)木本类型少,大多数种类为多年生草本植物,缺乏古老和原始类群,一些中国特有种衍生于其广布的亲缘种中,表明本区系具有年轻和衍生的性质;(4)我国西南高山区系和华北区系对该区系具有双重影响;(5)为青藏高原植物亚区唐古特植物地区同华北植物地区相互过渡的代表区系之一;(6)特有属和特有种少。在中国种子植物区系分区中,本区属于青藏高原植物亚区中的唐古特地区。
Resumo:
根据3窝14只甘肃鼠兔幼子56天的生长发育资料初步分析了甘肃鼠兔的生长发育规律。依据逻辑斯蒂曲线的拐点 ,甘肃鼠兔的体重生长可划分为加速增长相 ( 0~205日龄 )和减速增长相 ( 205日龄以后 )。按照瞬时生长率曲线的拐点 ,体重增长过程可分为 3个时期 ,即缓慢生长期 ( 0~6 5日龄 )、快速生长期 ( 6 5~ 345日龄 )和渐进生长期 ( 345日龄以后 )。文章对使用逻辑斯蒂方程和其它“S”形曲线描述动物生长过程存在的一些问题进行了讨论 ,认为:如果只用1条“S”形曲线描述动物的整个生长过程,就有可能会因为成年期动物生长规律的变化而破坏模型参数的生物学意义 ,同时引起模型拟合精度的降低。为克服这一问题,作者建议:在使用“S”形曲线拟合动物生长模型时,生长过程的资料最好不要覆盖体重波动较大的成年阶段。
Resumo:
目的:对红花岩黄芪化学成分进行研究。方法:用溶剂法、色谱法提取、分离红花岩黄芪化学成分,用波谱法鉴定其结构。结果:从红花岩黄芪中分离得到7 个化合物,碳三十醇(1) ,二十四碳酸( 2) ,5 ,7-二羟基-4′-甲氧基-6 ,8-二异戊烯基异黄酮(3) ,对香豆酸二十二酯( 4) ,豆甾醇( 5) , 5 ,7-二羟基-4 ,-甲氧基- 6-异戊烯基异黄酮( 6) ,咖啡酸二十四酯( 7) 。结论:化合物3 和4 为新天然产物,其它化合物均为首次从该植物中获得。
Resumo:
In this study, we conducted eddy covariance (EC) measurements of water vapor exchange over a typical steppe in a semi-arid area of the Inner Mongolia Plateau, China. Measurement sites were located within a 25-year-old enclosure with a relatively low leaf area index (similar to 1. 5 m(2) m(-2)) and dominated by Leymus chinensis. Energy balance closure was (H + LE) = 17.09 + 0.69 x (Rn - G) (W/m(2); r(2) = 0.95, n = 6596). Precipitation during the two growing seasons of the study period was similar to the long-term average. The peak evapotranspiration in 2004 was 4 mm d(-1), and 3.5 mm d(-1) in 2003. The maximum latent heat flux was higher than the sensible heat flux, and the sensible heat flux dominated the energy budget at midday during the entire growing season in 2003; latent heat flux was the main consumption component for net radiation during the 2004 growing season. During periods of frozen soil in 2003 and 2004, the sensible heat flux was the primary consumption component for net radiation. The soil heat flux component was similar in 2003 and 2004. The decoupling coefficient (between 0.5 and 0.1) indicates that evapotranspiration was strongly controlled by saturation water vapor pressure deficit (VPD) in this grassland. The results of this research suggest that energy exchange and evapotranspiration were controlled by the phenology of the vegetation and soil water content. In addition, the amount and frequency of rainfall significantly affect energy exchange and evapotranspiration upon the Inner Mongolia plateau. (c) 2007 Published by Elsevier B.V.
Resumo:
设计了一种基于双目立体视觉的视觉里程计来实现移动机器人在非结构化环境下的自主定位导航.对图像序列中提取的环境特征进行跟踪和匹配获得特征序列,根据三维重建的不确定性,利用最小二乘法和极大似然法对移动机器人进行定位和运动估计.在MATLAB环境下的仿真实验结果表明,视觉里程计可精确估计机器人位置和运动状态,对运动过程中的测量误差进行补偿,减小了机器人在非结构化环境下长距离导航的定位和运动状态估计累积误差,验证了这种视觉自主定位导航控制方法的可行性和有效性。
Resumo:
摘 要 随着全球市场竞争更加激烈,上层计划管理系统(MRPII/ERP)受市场影响越来越大,计划的适应性问题愈来愈突出,明显感到计划跟不上变化。因此,解决生产计划的适应性以及增加底层生产过程的信息流动,提高计划的实时性和灵活性,已经成为一个重要的研究课题。制造执行系统(MES),作为上层计划和底层控制的桥梁,能够通过传递信息,使得从订单下达到产品完成的整个生产过程进行优化。依赖准确的数据对工厂活动进行指导、启动、响应和报告。车间级计划与调度管理系统是整个(MES)系统的核心技术,是现代生产管理的关键问题之一。 本文结合陕西法士特齿轮有限公司装配制造执行系统的研究和开发,对装配生产线多品种变批量调度问题进行了深入的研究,给出了不同类型产品装配调度算法,及面向装配制造企业调度优化模型和变批量调度问题的算法。以先进的MES管理理念为依托,设计和开发齿轮装配线制造执行系统。并通过仿真软件对装配生产线进行仿真,进行初步资源优化。这些研究具有重要的理论意义和实用价值。 首先,本文阐述了MES产生及发展,分析了制造执行系统研究现状,并对装配制造车间计划调度优化问题研究。提出面向装配制造系统生产调度模型,给出了变批量生产调度问题的启发式算法。 其次,提出了装配制造执行系统功能模型。结合装配生产线的特点,针对装配车间管理,设计符合企业生产线运作与管理的制造执行系统,分析该系统的总体结构模型,并具体阐述了计划和调度模块设计的具体步骤,以及对一些问题的处理方法。并设计实现了齿轮MES的核心功能。 最后,讨论了计算机仿真技术在制造企业车间中的应用发展,以eM-Plant为平台,开发了装配生产线数字化仿真系统,并对装配车间生产线的资源优化设计作了分析,提出适合实际生产的策略。
Resumo:
China’s annual oil import volume has been increasing in recent years, but the oil price in the international market fluctuates and poses a severe threat to China’s economic development and national security. Therefore, it is of great importance to study the gas and oil exploration of Pre-Cenozoic Residual Basins in Yellow Sea. Yellow Sea has widespread and thick Mesozoic and Paleozoic strata that contain multilayer source rock. Hence, Yellow Sea Mesozoic and Paleozoic strata have good conditions of forming Pre-Cenozoic hydrocarbon reservoirs. Pre-Cenozoic Residual Basins are usually buried deep and then transformed many times in its long evolutional history. These characteristics make it difficult to apply a single method in exploring Pre-Cenozoic Residual Basins. On the other hand, it is highly effective to solve key problems of gas and oil exploration of Pre-Cenozoic Residual Basins in Yellow Sea by using integrated geological and geophysical methods which make full use of the advantages of various exploring techniques. Based on the principle of “the region controls the local; the deep restricts the shallow,” this study focuses on Pre-Cenozoic Residual Basins in Yellow Sea to describe the structure frame of its distribution, with gravity, magnetic, seismic, drill-hole and geological data and previous research findings. In addition, the distribution characteristics of Pre-Cenozoic Residual Basins in Yellow Sea are also analyzed. This paper explores the characteristics of error between gravity forward with constant density and gravity forward with variable density through the study on 2-D and 3-D gravity forward in frequency domain. The result shows that there is a linear relationship between error and depth of 2-D geological model but there is a nonlinear relationship between error and depth of 3-D geological model. The error can be removed according to its linear characteristics or statistical nature of nonlinear characteristics. There is also error between gravity inversion with constant density and gravity inversion with variable density due to variable density and edge-effect. Since there are not noticeable rules between the error and the two causes as variable density and edge-effect, this study adopts gravity inversion with variable density and methods to eliminate the edge-effect in basement inversion to improve inversion accuracy. Based on the study on the rock physical properties and strata distribution of Yellow Sea and adjacent regions, this study finds that there is a big density contrast between Cretaceous-Jurassic strata and their substratum. The magnetic basement of south Yellow Sea is regarded as top of Archeozoic-Proterozoic early strata, and there are double magnetic basements in north Yellow Sea. Gravity and magnetic data are used to inverse the gravity basement and magnetic basement of Yellow Sea, with seismic and drill-hole data as constrains. According to data of gravity and magnetic basement distribution, the depth of Cenozoic strata and previous research findings, this paper calculates the thickness of the Mesozoic and Pre-Mesozoic Residual Basins, draws the distribution outline of Pre-Cenozoic Residual Basins in Yellow Sea, and analyzes its macro-distribution characteristics. Gravity inversion is applied on a typical geological profile in Yellow Sea to analyze the characteristics of its fractures and magnetic basements. The characteristics of Pre-Cenozoic Residual Basins distribution outline in Yellow Sea and the fractures and magnetic basements of its typical profile shown by profile inversion provides new geophysical evidence for these structure views such as “the South Yellow Sea and the North Yellow Sea belong to different structural units” and “Sino-Korea and Yangtze blocks combine along Yellow Sea East Fractured Zone in Yellow Sea”.
Resumo:
Surface pollen assemblages and their relationhips with the modern vegetation and climate provide a foundation for investigating palaeo-environment conditions by fossil pollen analysis. A promising trend of palynology is to link pollen data more closely with ecology. In this study, I summarized the characteristics of surface pollen assemblages and their quantitative relation with the vegetation and climate of the typical ecological regions in northern China, based on surface pollen analysis of 205 sites and investigating of modern vegetation and climate. The primary conclusions are as follows:The differences in surface pollen assemblages for different vegetation regions are obvious. In the forest communities, the arboreal pollen percentages are more than 30%, herbs less than 50% and shrubs less than 10%; total pollen concentrations are more than 106 grains/g. In the steppe communities, arboreal pollen percentages are generally less than 5%; herb pollen percentages are more than 90%, and Artemisia and Chenopodiaceae are dominant in the pollen assemblages; total pollen concentrations range from 103 to 106 grains/g. In the desert communities, arboreal pollen percentages are less than 5%. Although Chenopodiaceae and Artemisia still dominate the pollen assemblages, Ephedra, Tamaricaceae and Nitraria are also significant important in the pollen assemblages; total pollen concentrations are mostly less than 104grains/g. In the sub-alpine or high and cold meadow communities, arboreal pollen percentages are less than 30%. and Cyperaceae is one of the most significant-taxa in the pollen assemblages. In the shrub communities, the pollen assemblages are consistent with the zonal vegetation; shrub pollen percentages are mostly less than 20%, except for Artemisia and Hippophae rhamnoides communities.There are obvious trends for the pollen percentage ratios of Artemisia to Chenopodiaceae (A/C), Pinus to Artemisia (P/A) and arbor to non-arbor (AP/NAP) in the different ecological regions. In the temperate deciduous broad-leaved forest region, the P/A ratios are generally higher than 0.1, the A/C ratios higher than 2 and the AP/NAP ratios higher than 0.3. In the temperate steppe regions, the P/A ratios are generally less than 0.1, the A/C ratios higher than 1 and the AP/NAP ratios less than 0.1. In the temperate desert regions, the P/A ratios are generally less than 0.1, the A/C ratios less than 1, and the AP/NAP ratios less than 0.1.The study on the representation and indication of pollen to vegetation shows that Pinus, Artemisia, Betula, Chenopodiaceae, Ephedra, Selaginella sinensis etc. are over-representative in the pollen assemblages and can only indicate the regional vegetation. Some pollen types, such as Quercus, Carpinus, Picea, Abies, Elaeagus, Larix, Salix, Pterocelis, Juglans, Ulmus, Gleditsia, Cotinus, Oleaceae, Spiraea, Corylus, Ostryopsis, Vites, Tetraena, Caragana, Tamaricaceae, Zygophyllum, Nitraria, Cyperaceae, Sanguisorba etc. are under-representative in the pollen assemblages, and can indicate the plant communities well. Populus, Rosaceae, Saxifranaceae, Gramineae, Leguminosae, Compositae, Caprifoliaceae etc. can not be used as significant indicators to the plants.The study on the relation of pollen percentages with plant covers shows that Pinus pollen percentages are more than 30% where pine trees exist in the surrounding region. The Picea+Abies pollen percentages are higher than 20% where the Picea+Abies trees are dominant in the communities, but less than 5% where the parent plants are sparse or absent. Larix pollen percentages vary from 5% to 20% where the Larix trees are dominant in the communities, but less than 5% where the parent plants are sparse or absent. Betula pollen percentages are higher than 40% where the Betula trees are dominant in the communities" but less than 5% where the parent plants are sparse or absent. Quercus pollen percentages are higher than 10% where the Quercus trees are dominant in the communities, but less than 1% where the parent plants sparse or absent. Carpinus pollen percentages vary from 5% to 15% where the Carpinus trees are dominant in the communities, but less than 1% where the parent plants are sparse or absent. Populus pollen percentages are about 0-5% at pure Populus communities, but cannot be recorded easily where the Populus plants mixed with other trees in the communities. Juglans pollen accounts for 25% to 35% in the forest of Juglans mandshurica, but less than 1% where the parent plants are sparse or absent. Pterocelis pollen percentages are less than 15% where the Pterocelis trees are dominant in the communities, but cannot be recorded easily where the parent plants are sparse or absent. Ulmus pollen percentages are more than 8% at Ulmus communities, but less than 1% where the Ulmus plants mixed with other trees in the communities. Vitex pollen percentages increase along with increasing of parent plant covers, but the maximum values are less than 10 %. Caragana pollen percentages are less than 20 % where the Caragana plant are dominant in the communities, and cannot be recorded easily where the parent plants are sparse or absent. Spiraea pollen percentages are less than 16 % where the Spiraea plant are dominant in the communities, and cannot be recorded easily where the parent plants are sparse or absent.The study on the relation of surface pollen assemblages with the modern climate shows that, in the axis 1 of DCA, surface samples scores have significant correlation with the average annual precipitations, and the highest determination coefficient (R2) is 0.8 for the fitting result of the third degree polynomial functions. In the axis 2 of DCA, the samples scores have significant correlation with the average annual temperatures, average July temperatures and average January temperatures, and the determination coefficient falls in 0.13-0.29 for the fitting result of the third degree polynomial functions with the highest determination coefficient for the average July temperature.The sensitivity of the different pollen taxa to climate change shows that some pollen taxa such as Pinus, Quercus, Carpinus, Juglans, Spiraea, Oleaceae, Gramineae, Tamariaceae and Ephedra are only sensitive to the change in precipitation.
Resumo:
1分散元素成矿研究概况。分散元素通常是指镉、镓、锗、铟、硒、碲、铊和铼等8种元素。由于它们在地壳中的平均含量低(一般为10^-9~10^-6级),不易形成独立矿物,难以发生有意义的富集。大百科全书云:“分散元素不形成独立矿床,它们以伴生元素方式存于其他元素的矿床内”。因此,长期以来,分散元素多被作为其他矿床的伴生组分,并侧重于含量和赋存状态两方面研究。