广州夏季大气中碳气溶胶浓度水平及污染特征

2002年6-7月于广州市3个采样点采集PM10和PM25样品,测定了PM10,PM25以及元素碳(EC)和有机碳(OC)的浓度.PM10和PM2.5平均浓度分别为124.77μg@m-3及78.13μg@m-3.PM10和PM2.5中的OC浓度分别为22.3μg@m-3和15.80μg@m-3,EC浓度分别为7.78和5.90μg@m-3,其中73.8%的OC和77.7%的EC存在于PM25中.在3个采样点PM10和PM25中,OC/EC比值均大于2.0,表明广州夏季大气存在二次污染.各种气象条件对OC、EC浓度及其比值的变化都有不同程度的影响,其中降水和风速是OC、EC浓度变化的主要气象因素.     

减摇水舱台架中伺服系统的分析与校正

船舶减摇水舱试验台架是研究和设计减摇水舱的重要试验设备．为了准确模拟船舶在海浪中的横摇运动，在台架系统中采用电液力矩伺服系统来模拟海浪力矩．主要对伺服系统进行分析与校正，使电液伺服系统能够正确模拟输入的力矩信号。     

一类非线性椭圆型方程的奇异边值问题(II)

本文弥补了文[8]的不足之处, 且与文[8]一起完整地推广了 Usami H.1989 年所得到的部分结果.     

SEM analysis of the changes of carbon layer structure of mesocarbon microbeads heat-treated at different temperatures

Mesocarbon microbeads (MCMB) with narrow size distribution, excellent sphericity and no obvious conglutination have been prepared with a coal tar pitch containing quinoline insolubles (QI) as the raw material. Optical microscopy and scanning electron microscopy (SEM) are used to examine the structure of the MCMB. It has been found that SEM technique shows the structural information of MCMB clearly in the form of micrographs even when the structure of MCMB is complex, while the optical technique is useful for analysis of the regular structure of the mesophase spheres but cannot be effectively used to analyze either the complex structure of the green MCMB or the structures of the further heat-treated ones at different temperatures. According to the characteristics of the carbon layers, the structures of the as-prepared MCMB in the present experiment could be classified as (I) Parallel Layer type structure and (2) Bent Layer type structure with the carbon layers gathering at one or two points in the MCMB. In the experiments, SEM is also utilized to investigate the structures of MCMB that are heat-treated at different temperatures. It has been found that the MCMB without any further heat-treatment show no layered-carbons, while the ones heat-treated at temperaturehigher than 1000℃ exhibit obvious layered carbons across their sections. When increasing the heat-treatment temperature, the carbon layers become thinner and flatter.     

Analysis of carbon isotopes in airborne carbonate and implications for aeolian sources

Methods were developed to determine the mass ratios of carbon isotopes in trace amounts of aerosol carbonate. A Finnigan MAT 252 mass spectrometer fitted with an on-line Kiel device was to determine the ^13C/^12C ratio in CO2 produced from the carbonate. A study using these methods was conducted to characterize the carbonate carbon isotopes in aerosol samples collected in Xi‘an on dusty and normal days during March and April 2002. Results of the study demonstrate that insights into the origin of the dust can be deduced from its isotopic composition. That is, the δ^13C ofcarbonate for dust storm samples ranged from -1.4‰ to -4.2‰, and this is consistent with sandy materials in dust source regions upwind. In contrast, for non-dusty days δ^13C ranged from -7.5% to -9.3‰, which is more similar to fine particles emitted from local surface soils. Comparisons of dust storm aerosols with surface soils from source regions and with aerosol samples collected downwind indicate that the δ^13C values did not change appreciably during longrange transport. Therefore, carbon isotopes have the potential for distinguishing among source materials, and this approach provides a powerful new tool for identifying dust provenance.     

2-D连续-离散系统的平衡模型降阶

基于局部能达性与局部能观性的分析给出2-D连续-离散系统状态空间模型的平衡实现,这一实现的第i个状态分量的重要性由系统的能达、能观阵的第i个对角元素所度量,去掉平衡实现系统弱能达、弱能观的部分,从而得到2-D连续-离散系统的模型降阶。所给示例表明,该方法具有良好的降阶效果。     

黄土高原西缘末次盛冰期以来古气候演化的有机碳同位素记录

综合CaCO3含量、碳酸盐碳、氧同位素资料，并结合研究区的区域特征，对兰州红咀寺剖面有机碳同位素气候指示意义进行了研究．结果表明，在黄土高原西缘，有机碳同位素δ^13Corg波动反映C3／C4植物比例改变，指示温度变化．δ^13Corg值偏正时，表明C4植物含量较大，反映温度较高．有机碳同位素和CaCO3含量、碳酸盐碳、氧同位素共同揭示了兰州地区末次盛冰期气候较全新世明显偏低，在11．5kaBP，13．9kaBP存在两次明显的降温；进人全新世以后，兰州气候开始逐渐变暖，但仍存在8．8kaBP、5．0kaBP和3．2kaBP的三次突然升温以及8．0kaBP、6．8kaBP和5．3kaBP的降温事件，说明了兰州地区气候变化的复杂性和不稳定性．     

室温下N-羟基琥珀酰亚胺活化酯法合成吡咯-2,5-二乙酰胺

在室温下用一锅反应法以二环己基碳二亚胺（DCC）（2 equiv．）为偶合试剂，使用过量（4equiv．）的胺，用N-羟基琥珀酰亚胺（Hosu）（2 equiv．）活化酯法合成了吡咯-2，5-二酰胺，且产率（70％）比在低温时（63％）有所提高．探讨了选用不同的合成方法及偶合试剂以及反应条件和试剂的用量对合成目标产物的影响．     

CCI土壤湿度产品在中国区的降尺度与融合研究

以欧洲航天局主/被动微波遥感融合的土壤湿度产品数据为主要数据源,结合地表参数、亮度温度、土壤质地、地形、降雨等辅助数据,提出基于移动窗口的线性、非线性联合的土壤湿度降尺度模型,对中国区域2003年1—12月的CCI土壤湿度产品数据进行降尺度,提高CCI土壤湿度数据的空间分辨率,使其更适用于农业、水文模拟等精细尺度的应用要求。为了克服CCI数据冬季缺失较多的情况,利用第3代再分析资料ERA-Interim表层土壤湿度的降尺度和重采样结果与之进行融合,生成空间覆盖完整的2003—2013年中国区月1 km土壤湿度数据集,并利用站点实测数据集对其进行了验证。结果表明,依据主/被动微波融合CCI、ERA-Interim再分析土壤湿度数据以及辅助数据的基于移动窗口和线性非线性集成的中国区地表土壤湿度降尺度和融合方法,提高了CCI土壤湿度数据集的空间分辨率和空间覆盖,同时还一定程度上提高了土壤湿度的估算精度。     

二茂铁修饰碳电极应用于钙钛矿太阳能电池的研究

二茂铁是一种具有良好氧化还原能力的金属有机化合物.近几年,二茂铁及其衍生物的光伏性能受到了极大的关注.本文将二茂铁引入钙钛矿太阳能电池,并成功组装了钙钛矿太阳能电池FTO/bl-TiO_2/mp-TiO_2/CH_3NH_3PbI_3/spiroOMeTAD/C/二茂铁(FC).二茂铁的HOMO能级(-4.8 eV)和碳电极的能级(-5.0 eV)与空穴传输相匹配.二茂铁层是将10 mg mL-1二茂铁氯苯溶液通过旋涂成膜制成,并覆盖在碳电极上.钙钛矿太阳能电池的能量转换效率由5.8%提升到6.2%.