1961-2010年河北省太阳直接辐射时空分布特征研究

利用1961-2010年河北省周边7个太阳辐射观测站的资料,拟合得出相对精确的河北省太阳直接辐射经验公式,分析了河北省太阳直接辐射时空变化特征。结果表明：河北省近50 a来太阳直接辐射年总量总体呈明显的下降趋势。其中,下降幅度相对较大的石家庄为25%,下降幅度相对较小的唐山为11%。河北省水平面太阳直接辐射年总量近50 a平均值空间差异较大,<2540MJ·m^-2 主要分布在邢台南部,>3510MJ·m^-2 主要分布在张家口西北部,大部分地区介于2540-3300MJ·m^-2 。河北省太阳能资源开发利用潜力比较大的区域主要在张家口的坝上地区。     

氧化多壁碳纳米管对水中钠离子的吸附研究

本文研究了强酸(体积比为3︰1的硫酸与硝酸)氧化的多壁碳纳米管对水中钠离子的吸附特性,考察了温度、初始浓度、吸附时间对钠离子吸附的影响。实验结果表明:多壁碳纳米管对钠离子的吸附能力随温度升高而下降;其吸附过程符合Langmuir吸附等温模型,但是在钠离子浓度较高时多壁碳纳米管的吸附特性更符合Freundlich等温模型;在温度为274K条件下,多壁碳纳米管对钠离子的吸附能约为-5.53KJ/mol即-57.3meV;化学反应焓变约为-9.31KJ/mol,表明混酸氧化的多壁碳纳米管对钠离子的吸附过程基本为物理吸附。     

Pockmarks on either side of the Strait of Gibraltar: formation from overpressured shallow contourite gas reservoirs and internal wave action during the last glacial sea-level lowstand?

Integrating novel and published swath bathymetry (3,980 km²), as well as chirp and high-resolution 2D seismic reflection profiles (2,190 km), this study presents the mapping of 436 pockmarks at water depths varying widely between 370 and 1,020 m on either side of the Strait of Gibraltar. On the Atlantic side in the south-eastern Gulf of Cádiz near the Camarinal Sill, 198 newly discovered pockmarks occur in three well localized and separated fields: on the upper slope (n=14), in the main channel of the Mediterranean outflow water (MOW, n=160), and on the huge contourite levee of the MOW main channel (n=24) near the well-known TASYO field. These pockmarks vary in diameter from 60 to 919 m, and are sub-circular to irregularly elongated or lobate in shape. Their slope angles on average range from 3° to 25°. On the Mediterranean side of the strait on the Ceuta Drift of the western Alborán Basin, where pockmarks were already known to occur, 238 pockmarks were identified and grouped into three interconnected fields, i.e. a northern (n=34), a central (n=61) and a southern field (n=143). In the latter two fields the pockmarks are mainly sub-circular, ranging from 130 to 400 m in diameter with slope angles averaging 1.5° to 15°. In the northern sector, by contrast, they are elongated up to 1,430 m, probably reflecting MOW activity. Based on seismo-stratigraphic interpretation, it is inferred that most pockmarks formed during and shortly after the last glacial sea-level lowstand, as they are related to the final erosional discontinuity sealed by Holocene transgressive deposits. Combining these findings with other existing knowledge, it is proposed that pockmark formation on either side of the Strait of Gibraltar resulted from gas and/or sediment pore-water venting from overpressured shallow gas reservoirs entrapped in coarse-grained contourites of levee deposits and Pleistocene palaeochannel infillings. Venting was either triggered or promoted by hydraulic pumping associated with topographically forced internal waves. This mechanism is analogous to the long-known effect of tidal pumping on the dynamics of unit pockmarks observed along the Norwegian continental margin.     

福建沿海年平均海平面年际、年代际变化特征及预测

利用福建沿海4个验潮站实测潮位资料,在分析实测资料变化趋势的基础上,采用谱分析的方法分析年平均海平面的变化趋势,得到了4个站年平均海平面变化模型,并对未来50年福建沿海的海平面上升趋势进行预测。     

2013年海洋和大气环流异常及对中国气候的影响

本文对2013年海洋和大气环流异常特征进行分析,讨论这些异常特征对中国气温和降水的主要影响。结果表明：2012/2013年冬季,北极涛动持续维持负位相,500 hPa位势高度场上,欧亚大陆中高纬环流呈“两槽一脊”的环流形势,乌拉尔山的高压脊持续偏强,而东亚槽也异常偏强,导致全国平均气温较常年同期偏低。季内,西伯利亚高压强度变化显著,与之相对应,我国气温季内阶段性变化大,前冬冷、后冬暖。进一步研究表明,前秋北极海冰的大幅偏少是造成东亚冬季风偏强的重要原因。2013年冬季至夏季,赤道中东太平洋海温异常偏低而海洋性大陆至西太平洋海温异常偏高,受此影响,夏季西太平洋副热带高压位置明显偏北,导致我国北方夏季多雨。与此同时,受西太平洋副热带高压下沉气流的控制,我国南方大部高温持续。2013年南海夏季风爆发偏早两候,结束偏晚4候,强度偏弱。     

利用多通道的光学超晶格产生对, 纠缠的连续变量频率梳

提出了一种实验上可行的,通过光学谐振腔内多通道参量下转换过程直接产生多色连续变量对纠缠频率梳的方案,腔内增益介质为周期极化的准相位匹配的钽酸锂(LiTaO₃)一维光学超晶格.通过连续变量纠缠判据证明了每个通道中产生的每对参量光之间是相互纠缠的.讨论了对纠缠频率梳的纠缠特性随系统参数的变化.此方案在量子通信网络中有着一定的应用前景.     

Progress in Studies of the Precipitation Diurnal Variation over Contiguous China

This paper summarizes the recent progress in studies of the diurnal variation of precipitation over con- tiguous China. The main results are as follows. （1） The rainfall diurnal variation over contiguous China presents distinct regional features. In summer, precipitation peaks in the late afternoon over the south- ern inland China and northeastern China, while it peaks around midnight over southwestern China. In the upper and middle reaches of Yangtze River valley, precipitation occurs mostly in the early morning. Summer precipitation over the central eastern China （most regions of the Tibetan Plateau） has two diurnal peaks, i.e., one in the early morning （midnight） and the other in the late afternoon. （2） The rainfall diurnal variation experiences obvious seasonal and sub-seasonal evolutions. In cold seasons, the regional contrast of rainfall diurnal peaks decreases, with an early morning maximum over most of the southern China. Over the central eastern China, diurnal monsoon rainfall shows sub-seasonal variations with the movement of summer monsoon systems. The rainfall peak mainly occurs in the early morning （late afternoon） during the active （break） monsoon period. （3） Cloud properties and occurrence time of rainfall diurnal peaks are different for long- and short-duration rainfall events. Long-duration rainfall events are dominated by strat- iform precipitation, with the maximum surface rain rate and the highest profile occurring in the late night to early morning, while short-duration rainfall events are more related to convective precipitation, with the maximum surface rain rate and the highest profile occurring between the late afternoon and early night. （4） The rainfall diurnal variation is influenced by multi-scale mountain-valley and land-sea breezes as well as large-scale atmospheric circulation, and involves complicated formation and evolution of cloud and rainfall systems. The diurnal cycle of winds in the lower troposphere also contributes to the regional differences     

利用HHT-EEMD方法分析云南区域GNSS应变时序孕震信息

地震的孕育和发生本质上都是地壳内部应力、应变能逐渐积累并突然或缓慢释放的结果,研究应变的变化过程对于地震危险性的判定具有重要意义。本文基于云南区域2013—2019年GNSS格网应变时间序列,利用专门适用于非线性非平稳信号处理的热门时频分析方法—整体经验模态分解（ensemble empirical mode decomposition,EEMD）的希尔伯特-黄变换（Hilbert-Huang transform,HHT）分析方法,探索云南区域中强地震前GNSS应变时序的时-频-能量分布特征,尝试挖掘应变时频信号中所携带的孕震信息。利用23号、42号格网对应的地震进行震例分析,结果显示：EEMD具有分频剖面的类似特征,它能够依据数据的时间特征尺度进行信号分解,较好地剖析信号在不同频率尺度上的变化特征;Hilbert变换能够通过瞬时频率、瞬时振幅等方式突出信号的局部瞬时特性,在固有模态分量（intrinsic mode functions,IMF）异常曲线识别无效的情况下仍能凸显异常;通过EEMD、残差趋势项分析、IMF异常识别和Hilbert变换综合动态分析应变时间序列的分析方法,能够在部分地震前夕发现一些潜在异常信息,为未来云南区域强震危险地点的判定提供一定的参考。     

中国晚侏罗世多瘤齿兽类哺乳动物的发现及其意义

多瘤齿兽是一类已绝灭的哺乳动物,其以后部牙齿上有很多小瘤(小的隆起,或者小尖)来适于咀嚼植物为特征。总的来说,它们的门齿和臼齿与那些啮齿类相似,但在演化时间上多瘤齿兽比新生代的啮齿类早的多。多瘤齿兽是杂食者,或者说是成功开拓了其它脊椎动物无法开拓的植食生境的植食者(可以树叶、种子、蕨类、裸子植物,再加上蠕虫和昆虫为食)。由于它们多种食性和运动方式,多瘤齿兽成为中生代数量最多的哺乳动物,几乎占侏罗纪和白垩纪时期所有哺乳动物种类的一半。它们的支系是哺乳动物历史上生存时间最长的支系,出现于170 Ma前,大约绝灭于35 Ma。但是,因为多瘤齿兽具有很多独特的、高度特化的牙齿和头骨特征,古生物学家们长期困惑于它们的进化起源。最近,中国辽西发现了一件产自晚侏罗世髫髻山组的多瘤齿兽类哺乳动物。由于其牙齿上发育明显的纹饰,如很多小的脊、沟、凹槽等,新发现的哺乳动物被命名为皱纹齿兽(Rugosodon)。另一方面,由于与皱纹齿兽亲缘关系最近的哺乳动物产自西欧的侏罗纪地层,因此其种名被命名为欧亚皱纹齿兽(Rugosodon eurasiaticus)。新发现为晚侏罗世时期欧洲和亚洲的哺乳动物具有高度的相似性提供了最新的证据。皱纹齿兽是一种夜行的哺乳动物,生活于气候温和的湖滨,与长羽毛的恐龙近鸟龙、翼龙类达尔文翼龙、大量节肢动物、其它几种哺乳动物共同生活于一起。根据与现生哺乳动物的比较,并依据欧亚皱纹齿兽手部比例、末端指节的形态等,推论欧亚皱纹齿兽很可能是地栖哺乳动物,或者说地栖比攀爬的可能性更大。这一发现对于研究多瘤齿兽早期的演化、食性分异、运动适应起源等具有重要的科学意义。