2015年北京、上海和拉萨PM2.5浓度日变化和日际变化分析

分析2015年北京、上海和拉萨3个城市PM_2.5浓度的时间序列, 讨论PM_2.5浓度的季节变化以及各城市PM_2.5浓度日际变化与日变化的相对重要性。从长期来看, 3个城市冬季PM_2.5浓度普遍大于夏季; 从短期来看, 北京和上海PM_2.5浓度主要呈现日际变化, 天气系统的影响远大于日变化。北京冬季PM_2.5浓度在一定程度上也呈现日变化, 但在夏季不明显; 上海在冬季和夏季都不呈现日变化; 拉萨的情况则相反, 当地的天气系统比较稳定, 日际变化不明显,PM_2.5浓度主要受日变化影响,PM_2.5浓度的日变化呈现明显的“双峰”现象。     

基于不同参考框架的GPS卫星天线校验

重新估计了基于不同参考框架的GPS卫星天线PCO(相位中心偏差)和PCV(相位中心变化)参数.计算过程中,通过固定测站天线的PCO和PCV,并将测站坐标强约束至不同的参考框架之下,降低了GPS卫星天线参数和接收机天线参数以及参考框架参数之间的相关性.结果显示,基于不同参考框架的同类型卫星天线PCV差异的平均值为0.726mm;与IGS发布值差异的平均值为0.844mm;基于新公布的IGS14参考框架的GPS卫星天线PCO估计结果与IGS(国际GNSS服务)发布值差异的平均值为-14.4mm,基于IGb08参考框架的卫星天线PCO估计结果与IGS发布值差异的平均值为-16.8 mm.以上结果表明,本措施提高了GPS卫星相位中心PCO/PCV的一致性,从而也能提高GNSS(global navigation satellite system)技术用于框架传递的连续性.     

漓江干流水体主要离子化学变化特征及影响因素

【目的】为保护漓江流域水环境及揭示区域碳酸盐岩风化过程提供基础数据及科学支撑。【方法】通过收集一个水文年漓江干流典型断面的水样,并进行水化学分析来研究水体中离子化学变化特征及其控制因素。【结果】漓江两个断面水化学类型都为Ca-HCO_3型,河水主要离子组分受到水岩作用的控制。两个断面对比来看,上游大面圩(DM)断面受到部分降雨输入的影响,而下游普益(PY)断面受到更加强烈的碳酸盐岩风化作用的影响。漓江两个断面HCO_3~-、Ca~(2+)离子浓度表现出雨季小于旱季的现象,主要受到雨季降雨和流量增大的影响,而SO_4~(2-)、NO_3~-、Cl~-离子浓度出现雨季大于旱季的现象,则主要受到农业活动、城市排污的影响。此外,由于人类活动的影响,漓江碳酸盐岩风化受到外源酸的影响,进而影响岩溶风化碳汇效应的评估。【结论】漓江典型断面水体优势离子(HCO_3~-、Ca~(2+))变化特征主要受到地质条件的控制,岩溶作用强度表现出显著的空间差异性;SO_4~(2-)、NO_3~-、Cl~-离子则受到不同人类活动的影响,表现出显著的季节变化和空间变化。     

无穷级数新的积分判别法

利用有界变差函数的性质,建立了比Cauchy积分判别法更广泛的新的积分判别法;利用实分析中的Lebesgue逐项积分定理,推广了文献[7]中一个数项级数收敛性判别法.     

变拓扑机构可变运动副设计目录研究

可变运动副作为变拓扑机构改变拓扑结构的关键所在,其结构设计是变拓扑机构构型综合的难点.基于可变运动副拓扑变化方式的研究,构建可变运动副设计目录,用于可变运动副的结构设计.分别针对可变运动副的改变轴线方位、改变数目和改变类型等三类拓扑变化过程,分析可变运动副的约束变化特征,并采用运动副约束函数的算术运算进行描述.在归纳设计可变运动副结构形式的基础上,对可变运动副拓扑变化方式、约束变化特征和对应结构等设计信息进行分类和汇编,构建可变运动副设计目录.应用实例表明,采用可变运动副设计目录,能快速有效地设计可变运动副结构,为含可变运动副的变拓扑机构构型综合提供了方便.     

Butterflies (Lepidoptera: Papilionoidea) of Mount Kilimanjaro: Nymphalidae subfamilies Libytheinae,Danainae, Satyrinae and Charaxinae

This paper, which presents an annotated checklist of the ‘lower Nymphalidae’ (Libytheinae, Danainae, Satyrinae, Charaxinae), is the fourth in a series on the butterfly fauna of Mount Kilimanjaro. Four genera of lower Nymphalidae (Danaus, Amauris, Bicyclus, Charaxes), with a total of 11 included species, are known or believed to occur within the main forest zone, from c. 1800 to 2800 m. Of these, only three species of Charaxes (Charaxes berkeleyi, Charaxes ansorgei, Charaxes xiphares) may be restricted locally to this primary forest. The lower slopes fauna, below 1800 m, is considerably richer, with a total of 11 genera and 41 species listed (8 species of which extend into the forest zone). Possible additional species, dubious earlier records, problems with African subspecies of Danaus chrysippus, a need for more work on certain Satyrinae, and classification of the genus Charaxes are discussed. An identification key to the subfamilies of Nymphalidae, and the 19 genera of Libytheinae, Danainae, Satyrinae, Charaxinae that occur in Tanzania, together with a key to the adults of all the species of these four subfamilies considered to occur or have occurred on Kilimanjaro, with 206 colour images, are included as online Supplementary Information.     

和而不同:英语中的中国因素

中国从19世纪初到现在接触和使用英语已有近两百年的历史,由于中西文化的相互影响和渗透,许多汉语的词汇逐渐进入英语,成为英语的一部分。中国英语以英国英语为核心,但有着鲜明的中国特色。本文拟从语言变异:中国因素的融入根源、顺应理论:验证中国因素的表现特色、英语全球化、本土化:引导中国因素的发展趋势三个方面阐释英语中的中国因素。     

Reproductive ecology of the glass frog Espadarana prosoblepon (Anura: Centrolenidae) in an urban forest of the Central Andes of Colombia

Population and reproductive behaviour aspects of the glass frog Espadarana prosoblepon are well known for populations from Central America, but similar information is lacking for populations from South America. We recorded the reproductive ecology of a population of the glass frog E. prosoblepon in the city of Armenia, Central Andes of Colombia. With weekly surveys with mark-recapture between December 2013 and November 2015, we monitored activity patterns and evaluated if the probability of males mating is associated to their body size or to chorus tenure (i.e. the number of nights a same individual is calling for attracting a mate). In addition, upon observing an amplexus, we recorded the behaviour of the individuals until oviposition and noted characteristics of egg clutch. We recorded 47 males and 32 females, nine amplexus events, eight ovipositions, and 21 egg clutches (35.4 ± 4.79 eggs per clutch, N = 29). Activity of males and females and the number of egg clutches were positively correlated to rainfall. Mating success of males was not associated to their body size, but it was positively associated to longer chorus tenure; clutches from large females had a higher number of eggs than clutches from small females. Oviposition occurred on average 3.76 ± 1.74 hours after we first observed the amplexus, occurring 93.1% of the time in fronds of Selaginella geniculata at an average height of 1.58 ± 0.44 m. After the oviposition, the male left the site, while the female remained between 30 and 45 min, partially covering the eggs. The reproductive behaviour of E. prosoblepon did not vary widely between a population in Costa Rica and our population in time to oviposition, and mating success of males associated to chorus tenure; however, in our study population we recorded a larger clutch size and the preference for S. geniculata fronds as oviposition substrate.     

温度、光照和磷质量浓度对小环藻、大型溞和金鱼藻共培养的影响

为了研究温度、光照和磷质量浓度对生物操纵效果的影响,选用小环藻、大型溞和金鱼藻分别作为浮游植物、浮游动物和大型水生植物的代表种,建立不同磷质量浓度(0.05、0.1、0.5、2mg/L)的水生微宇宙模型,研究不同温度梯度(15、20、25、30℃)、不同光照强度(1000、2600、4200、5800lx)及不同光暗比(10∶14、12∶12、14∶10、16∶8)条件下浮游动物和沉水植物的控藻效果.结果表明:磷质量浓度为0.05~0.5mg/L、温度在20~25℃时,大型溞和金鱼藻生长较好,对小环藻有明显的抑制作用;磷质量浓度为0.05~0.5 mg/L、光照强度在1000~4200lx时,大型溞和金鱼藻对小环藻有明显的抑制作用;强光(5800lx)有利于小环藻、金鱼藻的生长,但对大型溞有抑制;磷质量浓度为0.05~0.5mg·L-1,光暗比为14h∶10h时,大型溞和金鱼藻生长最好,可以达到很好的抑藻效果;当磷质量浓度相同时,温度30℃、光照5800lx时,培养液中氮磷去除率最高.