Changes in the Chemical Components of Light Crude Off During Simulated Short Term Weathering     

MA Qimin LUO Xia YU Zhigang 《中国海洋大学学报(英文版)》2007,6(3):231-236

To unambiguously identify spilled oils and to link them to the known sources are extremely important in settling questions of environmental impact and legal liability. The fate and behavior of spilled oils in the environment depend on a number of physicochemical and biological factors. This paper presents the results regarding changes in chemical composition of light crude oil during simulated short-term weathering based on natural environmental conditions. The results show that the saturated hydrocarbons of the light crude oil mainly distribute between n-C8 and n-C23 and the most abundant n-alkanes are found in the n-C10 to n-C16. The main chemical components of the light crude oil are n-alkanes and isoprenoids. The aromatic compounds are subordinate chemical components. Under the conditions of the weathering simulation experiment,n-alkanes less than n-C12,toluene and 1,3-dimethyl benzene are lost after 1 d weathering,the n-C13,n-C14,naphthalene and 2-methyl-naphthalene are lost on the fifth day of weathering,and n-C15 alkane components show certain weatherproof capability. The ratios n-C17/pristane and n-C18/phytane are unaltered and can be used to identify the source of the light crude oil during the first 8 d of weathering. After 21 d,the ratio pristine/phytane can not provide much information on the source of the spilled light crude oil. Triterpanes（m/z 191） as biomarker compounds of light crude oil are more valuable.  相似文献   

多模式智能路灯控制系统     

张秀再  罗歆瑶  韦镇余  沈旭晖 《南京气象学院学报》2014,6(6):510-514

使用AT89S52单片机作为主控芯片,设计了一种多模式智能路灯控制系统,该系统能够根据道路、巷口或定时应用3种情况进行工作模式选择,并根据环境光亮度决定是否启动所设定的工作模式.巷口工作模式时,系统通过红外传感器检测道路上有汽车或行人通过时,将识别信号送入单片机,由单片机控制交通灯开启;道路工作模式时,路灯处于开启状态,以保障行人畅行;定时模式时,通过DS1302定时模块,可以设定路灯的开关时间.此外,该系统还具有自动故障检测功能,功能全面,有较强的实用价值.  相似文献   

太原城市下垫面扩张对边界层特征影响的个例研究   总被引：1，自引：0，他引：1  

董春卿  郭媛媛  赵桂香  邱贵强 《干旱气象》2014,32(6):916-925

通过高分辨率卫星夜间灯光数据获取最新的城市地表分布,并利用高分辨率数值模式对2013年8月14~16日太原区域的一次高温过程进行研究,探讨城市下垫面扩张对大气边界层的影响。结果表明：基于DMSP/OLS夜间灯光数据对模式中地表参数修正后,能够更准确地反映太原主城区和高速公路沿线小规模建筑群的扩张,有效改善了模式的预报性能,显著提高对近地面气温、地表温度的预报能力。城市下垫面的扩张,使城区夜间升温明显,热岛强度增强。与1992年的城市化状况相比,晴空天气条件下,2012年太原城区夜间气温上升5℃,热岛强度升高2~3℃。城市下垫面扩张,改变了地表能量分配关系,使得地表感热传输明显加强,潜热通量明显减弱,城市冠层作用下的储热能力增强。边界层内部湍流交换、水汽输送等的进一步研究表明：城市地表水汽输送减弱,边界层水汽含量减少,2~4 km高度的水汽含量增加,湍流动能的影响高度增高,湍流混合加剧;14：00,城区边界层高度抬高了800 m,城市上空混合层加深,持续时间更长。  相似文献   

养殖方式、光照强度对哲罗鱼稚鱼生长与存活的影响   总被引：1，自引：0，他引：1  

郭文学  尹家胜  佟广香  张永泉  白庆利 《海洋与湖沼》2014,45(2):264-273

采用生态学方法,研究了养殖方式、光照强度对哲罗鱼稚鱼生长与存活的影响。结果表明:在养殖方式实验中,哲罗鱼稚鱼体长、体质量均以室内静水组为最高,室内流水组其次,室外流水组最低。存活率以室内流水组为最高,室外流水组次之,室内静水组最低。统计分析表明养殖方式对哲罗鱼稚鱼终末体长、体质量、特定生长率、体长生长参数以及体长、体质量变异系数的影响均达到极显著水平(P0.01)。在光照实验中,哲罗鱼稚鱼的存活率、体长、体质量及特定生长率、体长生长参数均随光照强度的增加而增加,说明在哲罗鱼稚鱼室内培育阶段,适当地增加部分光照有利于其存活、摄食与生长。本研究结果为哲罗鱼高效养殖提供了科学依据。  相似文献   

Combined effects of light intensity and NH^＋4-enrichment on growth,pigmentation, and photosynthetic performance of Ulva prolifera （Chlorophyta）     

徐智广  吴海一  詹冬梅  孙福新  孙建璋  王广策 《中国海洋湖沼学报》2014,32(5):1016-1023

The aim of this study was to investigate the effects of light intensity and enhanced nitrogen supply on the growth and photosynthesis of the green-tide macroalga, Ulva prolifera. Thalli of U. prolifera were grown in natural or NH 4 +-enriched seawater under two different light intensities for 7 days, and then the growth rate, pigmentation, and photosynthetic performance of the thalli were evaluated. The results show that the relative growth rate(RGR) was markedly higher under the high light level than under the low light level. Enrichment with NH 4 + enhanced the RGR under high light intensity, but did not affect RGR under low light intensity. In low light conditions, NH 4 +-enrichment resulted in a marked decrease in the maximal photosynthetic rate( P m) and the maximum carbon fixation rate( V max), but it did not affect the half saturation constant for carbon( K 0.5) or the ratio of V max to K 0.5, which reflects the carbon acquisition efficiency. In high light conditions, P m, K 0.5, and the dark respiration rate( R d) increased under NH 4 + enrichment, but V max and the V max / K 0.5 ratio decreased. Regardless of the light intensity, NH 4 +-enrichment did not affect the apparent photosynthetic efficiency( α), which refl ects the ability of the alga to use light energy at low light levels. Under both low and high light intensities, the chlorophyll a(Chl a), chlorophyll b(Chl b), and carotenoids(Car) contents in thalli were higher in NH 4 +-enriched than in natural seawater, except that there was a decrease in the Chl b content of thalli in NH 4 +-enriched seawater under low light intensity. Therefore, NH 4 + enrichment improved the growth and photosynthetic performance of U. prolifera under high light intensity, but not under low light intensity. We discuss the possible mechanisms underlying these physiological responses.  相似文献   

光学显微镜成像方式及投影冷光源的分频合成探讨     

赵应权  沈忠民  王鹏 《岩矿测试》2014,33(5):674-680

传统显微镜光源主要包括卤素灯光源、纯水过滤热射线光源、LED光源等,由于卤素灯光源含有大量760~1400 nm区段的红外线,纯水过滤热射线光源滤除红外线不彻底且水会导致透射光线的部分散射,LED光源在500 nm波长附近的光照强度不足、波形存在缺陷,容易灼伤样品或使成像质量受限,都难以满足需要采用大功率冷光源进行无损、高质量显微观察成像和测试的要求。本文在总结光学显微镜的成像方式、光源类型及各类光源优缺点的基础上,提出了采用三棱镜-凸透镜组分频合成冷光源的新思路。该思路首先利用三棱镜将卤素灯光源光谱按频率顺序打开,然后选择可见光区域内的光谱,用凸透镜组校正可见光方向后,再由三棱镜将这些可见光合成不含热射线的冷光源。理论和砂岩荧光薄片实际测试效果表明,该方法既可完全排除热射线,从而使样品免遭受破坏,又保持了完整的可见光光谱,解决了大功率冷光源红外线生热和光谱存在缺陷的难题,这为采用大功率冷光源的光学显微镜投影高质量成像提供了新的方法及切实可行的依据。该套分频合成光源的装置主要配置为:玻璃材质的同规格的三棱镜与凸透镜各两个,卤素灯光源一个。结构简单,可在需使用大功率冷光源进行无损成像和测试等方面获得广泛的应用。  相似文献   

激光扫描实时获取水下图象信息的方法与系统   总被引：1，自引：1，他引：0  

郑冰  李欣  谭锐  王国宇 《中国海洋大学学报(自然科学版)》2000,30(4)

报道一种实时大视角、全景深获取水下图象的新方法。该方法试图解决在无人摇控潜器(ROV)和自治式潜器 (UUV)走航式获取水下清晰图象时 ,遇到的激光在水下传输过程中后向散射噪声问题 ,建立了一种具有宽视角、全景深性能的水下激光扫描系统。用这种方法和系统在空气中和水中做了大量的实验 ,并讨论了这种方法和系统的应用前景。  相似文献   

DMSP-OLS与NPP-VIIRS夜间灯光遥感影像数据整合     

何立恒  吕萌  朱婷茹 《测绘通报》2023,(1):31-38

DMSP-OLS夜间灯光遥感数据截至2013年,现已被NPP-VIIRS夜间灯光数据取代。因此,要获得长时间序列且稳定的夜间灯光数据集,需要整合两类夜间灯光数据。基于此,本文提出了基于重采样的两类数据整合方法,对2013—2020年NPP-VIIRS数据进行模拟,最终建立了1992—2020年长时间序列校正—模拟DMSP-OLS夜光遥感数据集。结果表明,基于重采样的整合方法效果良好(城市区域Pearson相关系数ρ=0.9852,RMSE=3.4607),整合数据集与相关社会经济参考量高度契合(影像DN值总和与GDP的相关系数ρ=0.946,与人口的相关系数ρ=0.971,二次多项式模型拟合R²≈0.98,RMSE<5.55),优于已有研究。因此,利用该方法整合后的数据集能更好地支撑基于夜间灯光影像的长时间序列研究。  相似文献   

光及补料条件对室内管道光反应器中三角褐指藻生长和岩藻黄素积累的影响     

诸德斐  杨润青  宋培钦  魏东 《广东海洋大学学报》2021,(2)

【目的】制备富含岩藻黄素的三角褐指藻(Phaeodactylum tricornutum)生物质。【方法】采用470 L室内管道光生物反应器系统,研究自养培养下光源、调光策略、补料培养操作条件对于细胞生长、生物量浓度和岩藻黄素积累的影响。【结果】在采用LED灯、梯度提升照度及重复补料半连续培养模式下,三角褐指藻细胞密度、生物量和岩藻黄素产率最高分别可达3.16×10⁷mL^-1、1.64 g/L和1.90 mg/(L·d),分别是日光灯为光源条件下的2.77倍、3.09倍和2.38倍(P<0.01)。【结论】在管道光生物反应器中获得的自养培养条件,可强化三角褐指藻生物量和岩藻黄素积累,为三角褐指藻积累岩藻黄素的室内可控规模化技术开发提供指导。  相似文献   

Sputtering and high altitude meteors     

K. A. Hill  L. A. Rogers  R. L. Hawkes 《Earth, Moon, and Planets》2004,95(1-4):403-412

Conventional ablation theory assumes that a meteoroid undergoes intensive heating during atmospheric flight and surface atoms are liberated through thermal processes. Our research has indicated that physical sputtering could play a significant role in meteoroid mass loss. Using a 4th order Runge-Kutta numerical integration technique, we tabulated the mass loss due to the two ablation mechanisms and computed the fraction of total mass lost due to sputtering. We modeled cometary structure meteoroids with masses ranging from 10⁻¹³ to 10⁻³ kg and velocities ranging from 11.2 to 71 km s⁻¹. Our results indicate that a significant fraction of the mass loss for small, fast meteors is due to sputtering, particularly in the early portion of the light curve. In the past 6 years evidence has emerged for meteor luminosity at heights greater than can be explained by conventional ablation theory. We have applied our sputtering model and find excellent agreement with these observations, and therefore suggest that sputtered material accounts for the new type of radiation found at great heights.  相似文献