Comparing the diurnal variations in the SuperMAG auroral electrojet indices SML and SMU

Diurnal variations of the SuperMAG auroral electrojet indices (SML and SMU) were examined for the period of 1980–2010, and the differences between SML and SMU were especially analyzed. The diurnal variation of SML with a maximum at around 1100 UT has a prenoon-postnoon asymmetry. At solstices, the diurnal variation of SML is much stronger than that at equinoxes. For the SMU, two maxima are recorded in the diurnal variation with the bigger one at 1700 UT and the smaller one at 0400 UT. The seasonal variations are not obvious in the UT variation characteristics of SMU although the intensity of SMU is changed remarkably season by season. For both SML and SMU, the contributing stations are located at higher geomagnetic latitude around 1600 UT and at lower geomagnetic latitude around 0400 UT. These results indicate that: (1) the SML is mostly controlled by the convection electric field. Its diurnal variation is mainly correlated with the equinoctial and R-M hypothesis; (2) the SMU is largely controlled by the ionospheric conductance. Its diurnal variation is tightly correlated with the solar radiation.     

Trend, seasonal and diurnal variations of atmospheric CO2 in Beijing

The concentration of atmospheric CO2 in Beijing increased rapidly at a mean growth rate of 3.7%@a?1 from 1993 to 1995. After displaying a peak of (409.7±25.9) ?mol@mol?1 in 1995, it decreased slowly. Both the almost stable anthropogenic CO2 source and increasing biotic CO2 sink contribute to the drop of CO2 concentration from 1995 to 2000. The seasonal variation of CO2 concentration exhibits a clear cycle with a maximum in winter, averaging (426.8±20.6) ?mol@mol?1, and a minimum in summer, averaging (369.1±6.1) ?mol@mol?1. The seasonal variation of CO2 concentration is mainly controlled by phenology. The mean diurnal variation of atmospheric CO2 concentration for a year in Beijing is highly clear: daily maximum CO2 concentration usually occurs at night, but daily minimum CO2 concentration does in the daytime, with a mean diurnal difference more than 34.7 ?mol@mol?1. It has been revealed that the interannual variations of atmospheric CO2 concentration in winter and autumn regulated the interannual trend of atmospheric CO2, whereas the interannual variation of CO2 concentration in summer affected the general tendency of atmospheric CO2 in a less degree.     

Interannual and interdecadal variations in the North Atlantic Oscillation spatial shift

The spatial shift of the North Atlantic Oscillation (NAO) is analyzed by using the Twentieth Century Reanalysis version 2 dataset and identifying NAO action centers directly on winter mean sealevel pressure (SLP) anomaly maps. The spatial shift of the NAO is characterized by four NAO spatial shift indices: the zonal and meridional shifts of the NAO southern and northern action centers. It is found that the zonal and meridional shift trends of the NAO action centers move along a path of southwest-northwest direction. Spectral analysis shows that the four NAO spatial shift indices have periodicity of 2-6 years and the NAO index has periodicity of 2-3 years in terms of high-frequency variations. On a decadal time scale, the NAO spatial shift indices are closely (positively) related to the NAO index, which is in agreement with previous studies of the relationship between the NAO index and the spatial shift of the NAO pattern. However, there is no relationship between the NAO index and the meridional shift of the northern action center on an interannual time scale. The significant relationship between the NAO index and the interannual variability of NAO spatial shift indices is very likely to be associated with synopticscale Rossby wave breaking, which generates surface pressure anomalies and thus affects the phase and pattern of the NAO. The correlations of winter westerly winds over 90°W-0° and the NAO index and the NAO spatial shift indices have a ’+ - + -’ structure from the Equator to the North Pole. Although there is close correlation between the NAO spatial shift indices and the strength of the zonal winds in the North Atlantic region, the effect of the zonal winds on the NAO spatial shift differs at different latitudes. Hence, the role of the zonal winds is probably a result of the NAO spatial shifts.     

荒漠沙蜥栖息地选择的季节和地理变异

通过主成分分析、方差分析和非参数检验比较荒漠沙蜥利用生境和潜在可利用生境的9个生态因子,目的是调查其栖息地选择的地理和季节变异.研究表明荒漠沙蜥栖息地选择不存在性别差异,但存在显著的季节和地理差异.多数种群在繁殖前均选择植被盖度较低的、日晒条件好的生境,而繁殖后选择草本盖度较高、食物条件较好的生境.对照样方季节变异不明显,表明该差异主要由沙蜥的主动选择引起.繁殖前温度相对较低,沙蜥为了获得较高体温、保证生殖腺发育而选择低盖度生境;繁殖后期为了避免高温、快速积累越冬所需脂肪而选择高草本盖度生境.无论对照样方还是选择样方均存在显著的地理变异,且参数的变异模式相同,表明栖息地的地理差异与生境的差异有一定关系.此外,在不同的生境条件下,沙蜥也会权衡逃避敌害和取食的利害,而做出有利于其存活和繁殖的选择.如在灌丛盖度较高逃避捕食较容易的生境会较多地考虑日晒和取食,而在植被盖度较低食物不利时侧重取食.     

Dynamic Variations and Influencing Factors of Groundwater Levels in Lhasa City

This paper focuses on the dynamic variation of groundwater level in Lhasa city. According to the data, the obvious characteristic of the groundwater level of the city is that it is changing seasonally. Lhasa is divided into three districts according to hydrogeological conditions: the alluvial plain of the Lhasa-river, the alluvial plain of the Doilung-river, and the alluvial fan of intermountain, which presents a downward trend, a slight upward trend and basically stabilizing trend over the years individually. The analysis indicates that meteorological and hydrological factors lead to the obvious dynamic change of the groundwater level. However, more and more human activities and over-exploitation of the groundwater cause the downward trend in the groundwater level.     

田间珊瑚树净光合速率及生态因子的日变化

自然条件下 ,对珊瑚树叶片光合作用日进程的研究结果表明 :夏季晴天珊瑚树阳叶净光合速率日进程曲线为“双峰”型 ,光合效率午间明显降低 ,主要由非气孔限制引起 .应用逐步多元回归方法 ,得到珊瑚树净光合速率日变化的最优方程为 :Y =- 4 9.8837 0 .0 10 3X1 0 .0 6 75X4 0 .4 913X5(复相关系数R =0 .84 12 ,F值 =4 .84 2 9,显著水平p =0 .0 4 82 ) .偏相关分析和通径分析表明 ,光合有效辐射、空气相对湿度和空气CO2 浓度与净光合速率的日变化有着极显著和显著的相关关系 ,是影响净光合速率的直接主要因子 ,影响的大小顺序为 :光合有效辐射 >空气相对湿度 >胞间CO2 浓度     

虎纹蛙促性腺激素及其释放激素含量的日变化

利用具有高度特异性的放射免疫测定法,研究了10月份虎纹蛙成蛙脑和脑垂体GnRH、以及脑垂体和血浆GtH含量的日变化,结果表明：雌蛙脑和脑垂体mGnRH含量、以及脑垂体cGnRH-Ⅱ含量都存在有明显的日变化;雄蛙脑垂体和血浆LH水平,以及雌、雄蛙血浆FSH水平也都存在明显的日变化;对各种激素日变化产生的原因进行了探讨.     

佛山市禅城区景观格局粒度效应分析Ⅰ——景观制图与景观指数选取

以佛山市禅城区作为研究对象,在其土地利用分类基础上,利用GIS软件、景观格局分析软件（Fragrats3.3）和Excel软件,从景观水平和斑块类型水平上分析了粒度变化对禅城区、老城区和南庄镇3类景观格局的影响,并对比分析南庄镇和老城区在不同粒度下的尺度效应,寻找不同景观的适宜分析粒度,从而为选择适宜粒度进行景观指数的计算和尺度转换提供理论依据。结果表明,景观指数具有粒度效应：在景观水平上,禅城区的适宜尺度为5、20～40和120～140 m区间,老城区的适宜尺度为10、20～40和120～140 m区间,南庄镇的适宜粒度为5、70、110 m;在斑块类型水平上,禅城区和老城区的适宜粒度均为10或120～140 m区间,南庄镇的适宜粒度大致是粒度为10、20或120～150 m区间。     

武夷山不同海拔植被带土壤微生物量磷的时空变异

为了阐明我国中亚热带森林区土壤微生物量磷的时空变异特征及其主要影响因子,在福建省武夷山国家自然保护区选择了常绿阔叶林(EBF,海拔500 m)、针叶林(CF,海拔1 200 m)、亚高山矮林(SDF,海拔1 800 m)和高山草甸(AM,海拔2 100 m)共4种不同海拔植被类型作为实验样地进行了相关实验研究。结果表明:土壤微生物量磷含量随着海拔高度的增加显著增加,其中在0～10 cm的表层土壤中,EBF、CF、SDF和AM 4种植被类型土壤微生物量磷年均值分别为12.35、14.63、23.98和31.99 mg/kg,除EBF与CF两种植被类型之间土壤微生物量磷差异不显著外,其他不同海拔植被类型之间土壤微生物量磷含量均差异显著(p<0.05)。土壤微生物量磷含量在0～10 cm土壤表层最高,随着土壤深度的增加而逐渐减小。不同植被类型及不同土壤层次中土壤微生物量磷均具有明显的季节动态变化且变化规律一致,均表现为冬季最高,秋季次之,夏季最低。相关分析表明,在0～10 cm土层影响土壤微生物量磷沿海拔梯度空间变异的主要因子是土壤湿度和土壤有机质含量,而影响土壤微生物量磷季节性变异的主要因子是土壤湿度和土壤温度。     

距序拓扑指数与烷烃及其衍生物沸点的QSPR研究

以有机物系统命名法为基础,结合原子的结构与成键特征,定义原子的染色距离序数(fi),其对烷烃(RH)及其衍生物(RL)分子中非氢原子实现惟一性表征.依据邻接矩阵,由fi构建距序拓扑指数(mK)及其逆指数(mK').其中1K,0K'及分子中碳原子的最大支化度分别与72种脂肪醛酮、85种烷烃、24种卤化物和15种脂肪醇的沸点Tb关联,复相关系数依次为0.999 5,0.998 5,0.993 0,0.999 7.0K,1K与这196种RH及RL沸点的QSPR模型为:ln(678-Tb)=6.137 462-0.024 471 0K-0.002 452 1K,R=0.996 2, F=12 701.对72种脂肪醛酮采用随机删除所建模型的平均复相关系数为0.999 47,表明所建模型具有总体稳健性.结果表明, 1K不仅简并度低,与沸点相关性高,而且计算简单,物理意义明确,应用范围广.     

发展经济学下的不平等测度方法评估

不平等测度是发展经济学中一个非常重要的研究方面。在经济学角度讲,不平等是一个不确定的概念,其与寿命、个人能力及政治自由等紧密相联。发展经济学中,主要的测度指数有相对平均离差、变差系数、基尼系数、Theil指数、道尔顿测度、阿特金森测度等。本文集中分析几个主要测度方法的基本数学过程,并通过不平等测度的公理化原则对其进行了简单的评估。     

互补变分原理及其在微扰近似理论中的应用

以正则变分和线性变分函数为基础,对互补变分原理作了论证,推导出二阶能量修正的上界和不受任何条件限制的下界,并对具体计算方法作了详细的研究。得出互补变分原理在微扰理论近似中应用所求氢原子的极化率结果比一般的变分法和微扰法所得结果更接近于实验值。并指出这理论可以推广应用到激发态或处理高阶修正问题。     

用变异系数统一考核棉纺半成品和成品质量探讨

棉纺工业生产的半成品、成品质量考核指标较多，并且数据处理的理论与方法不一致，不适应现代化质量管理的需要。本文拟采用变异系数CV（％）值统一考核与控制棉纺半成品、成品质量，作为尝试。     

季风的年变程

对流层低层的风可以看成是二部分的组合,一部分是季风,而另一部分是非季风的行星风。在对流层低层行星风的季节性变化很小,所以可以用多年平均的年平均风来代表。这样,就可以将季风从实际风中分离出来。作者用这种分离出来的季风讨论了亚洲、非洲、澳洲和印度尼西亚四个著名的季风区季风的年变程。     

英语口语和书面语中的名词短语对比研究

文章运用TIGERSearch软件中两种不同的语料库模版Christine和Susanne,研究以代词和名词为中心词的名词短语在英语口语和书面语中作主语和宾语的频率,将所得结论与其他学者的研究结果进行比较,进一步证明名词短语在英语口语和书面语中运用时的区别。     

俄语名词的限定意义与相应英语表述之比较

俄语的语法规则复杂,尤其是名词格的用法更是意义繁多,十分灵活,不易把握。这里针对俄语名词格的限定意义将之与英语相应表达作一比较。希望能对学习俄语的英语专业学生有所帮助。     

湖南省信息化水平测算及预测

用信息化指数模型对湖南省1985－2000年信息化水平进行测算和分析，并对湖南省信息化未来发展水平状况进行预测，就如何提高湖南省信息化水平提出了若干对策。     

Observed and simulated features of the CO2 diurnal cycle in the boundary layer at Beijing and Hefei,China

The mechanism of the CO2diurnal cycle is a basis for investigating the carbon budget and its impacts on climate and environment change.Regional diurnal variations in CO2concentration based on observations and modeling have been studied widely.However,few studies have focused on the pattern of the CO2diurnal cycle in China.In this study,a three-dimensional global chemical transport model,Goddard Earth Observing System(GEOS)-Chem,was applied to simulate the CO2concentration and its variation over China from 2004 to 2012.Meanwhile,we also analyzed the CO2concentration as observed by two eddy covariance flux observation towers,one located in Beijing(39°580N,116°220E)and one in Hefei(31°550N,117°100E),using LI-COR 7500A infrared gas analyzers.Observations showed the amplitude of the CO2diurnal cycle at Hefei to be larger than at Beijing,due to stronger ecological activities.GEOS-Chem successfully captured the main aspects of the diurnal cycle of the CO2concentration in the boundary layer observed at both Beijing and Hefei.However,some discrepancies between the model and observations did exist;specifically,the model tended to underestimate the amplitude of the CO2diurnal cycle.The data also showed that traffic emissions significantly enhanced the CO2concentration in the boundary layer.     

山西荒漠化类型与动态演变研究

＂荒漠化＂是指包括气候变异和人类活动在内的种种因素造成的干旱、半干旱和亚湿润干旱地区的土地退化。针对山西省荒漠化的动态变化,结合多年平均降水量、平均蒸发量、水蚀模数等因素,综合分析了山西省荒漠化动态变化的原因与现状。     

传统文化影响下的中西方大学物理教育比较研究

传统文化深藏于一个国家和民族的内部,不同的文化孕育了中西方不同的教育思想。大学物理作为一门自然学科的基础课程,有其本身所固有的教学规律,但由于中西方传统文化的差异,其教学模式、教学理念、教学方法在很大程度上都体现出传统文化的特性。