Error assessment of grid-based diffuse solar radiation models

Two grid-based diffuse solar radiation models, ESRI’s Solar Analyst (SA) and Kumar’s model (KM), were assessed using a data-independent approach where each model’s numerical results of clear sky diffuse radiation on V/U-shaped surfaces were compared with analytical results derived using each model’s assumptions. SA and KM consistently underestimate and overestimate, respectively, diffuse radiation at daily, seasonal, and annual scale relative to the analytical results based on each model’s parameterizations. Overall, SA performs better than KM in modeling diffuse radiation at most timescales. While SA and KM have similar error in calculating diffuse radiation on a horizontal surface, SA models sky view factor much better than KM, with mean absolute relative differences of 0.76% and 17.02%, respectively. KM has a large error in sky view factor as it does not consider the shading effect from surrounding terrain. Sky view factor error in SA is small and use of more zenith divisions can further reduce the error. Based on our previous study, model performance on clear sky global solar radiation was also evaluated. Overall, KM performs better than SA in global radiation as KM performs better than SA in modeling direct radiation which is the major component of global radiation.     

隧道变形过程中电磁辐射强度参数的变化规律

根据丽江至香格里拉铁路中义隧道变形及电磁辐射的现场监测资料,对隧道变形过程中的电磁辐射特性及电磁辐射强度极大峰值事件数N、超过强度平均值的极大峰值事件数M与隧道水平收敛变形的关系进行了统计分析。研究表明:(1)电磁辐射最大强度平均值E在初期支护破坏前,随隧道变形的增大而增大,初期支护破坏后,随隧道变形的增大而减少,电磁辐射最大强度平均值先升后降的出现时间与初期支护破坏的时间接近。(2)电磁辐射强度极大峰值事件数、超过强度平均值的极大峰值事件数的波动速率V_N、V_M与隧道变形速率呈正线性相关关系;电磁辐射强度极大峰值事件数、超过强度平均值的极大峰值事件数的百分比λ_N、λ_M与隧道累计变形呈正线性相关关系。结论对深化地下洞室变形过程中的电磁辐射特性的认识,提高电磁辐射监测技术的现场应用水平具有指导意义。     

同步辐射X射线微探针研究宝石矿物成色与某些微量元素的关系

利用北京正负电子对撞机（ＢＥＰＣ）提供的同步辐射（ＳＲ）白光为激发源（束斑尺寸１００μｍ×１００μｍ，计数时间１００ｓ／点），研究了蓝宝石、红宝石、紫晶、祖母绿的天然、加工和合成品的微量元素成分，对于鉴别宝石提供了有益的信息。     

Changes of the first Schumann resonance frequency during relativistic solar proton precipitation in the 6 November 1997 event

The variations of the first mode of Schumann resonance are analyzed using data from Kola peninsula stations during the solar proton event of 6 November 1997. On this day the intensive flux of energetic protons on GOES-8 and the 10% increase of the count rate of the neutron monitor in Apatity between 1220 and 2000 UT were preceded by a solar X-ray burst at 1155 UT. This burst was accompanied by a simultaneous increase of the Schumann frequency by 3.5%, and the relativistic proton flux increase was accompanied by 1% frequency decrease. These effects are explained by changes of the height and dielectric permeability of the Earth-ionosphere cavity.     

共聚焦点道集偏移速度建模

偏移速度建模可在多种道集实现.基于等时原理和差异时移分析,提出了共聚焦点道集偏移速度建模方法.偏移速度的更新是利用约束参数迭代反演实现,模型的参数化主要依据实际情况而定.为适应横向变速,选用了垂直速度梯度参数.模型试算表明:偏移速度相对误差在0.25%范围内,反射层深度误差小于10m.     

Fourier transform infrared microspectroscopic characterization of Neoproterozoic organic microfossils from the Fifteenmile Group in Yukon,Canada

Conventional and synchrotron radiation‐based (SR) Fourier transform infrared microspectroscopies (micro‐FTIR) were applied to four types of ~ 810 Ma organic‐walled microfossils together with diffuse organic matter (OM) and one irregularly shaped structure from the Fifteenmile Group, in Yukon, Canada, for their chemical characterization. The microfossils comprised one filamentous type and three coccoidal types. Micro‐FTIR mapping analysis revealed the micrometer‐scale, spatial distribution of organic components (aliphatic C‐H bonds) and carbonate in the microfossils. Based on comparisons of CH₃/CH₂ peak height ratios (R_3/2) and morphologies of the microfossils (without the diffuse OM) to those of previously described Proterozoic microfossils, possible affinities of the microfossils are suggested, as follows. Palaeolyngbya? and Glenobotrydion belong to bacteria. Myxococcoides is not clearly characterized due to the significant mixing with diffuse OM containing abundant aliphatic C‐H groups. The irregularly shaped structure may represent a eukaryote. The diffuse OM may represent a mixture of decomposed microbial cells and extracellular polymeric substances (EPS). SR micro‐FTIR measurements of two coccoid types (Glenobotrydion and Unnamed Coccoid Form D) revealed that the R_3/2 values of the internal spots with wall structures are similar to those without wall structures in Glenobotrydion: those values from Unnamed Coccoid Form D were different. The results suggest that these two coccoids are different chemically as well as morphologically. Micro‐FTIR characterization of the organic‐walled microfossils together with morphological analysis provides new insight into their biological affinities.     

区域气候模式对不同的积云参数化方案在青藏高原地区气候模拟中的敏感性研究

本文使用MIROC3.2_hires模式输出资料作为RegCM3 (The ICTP Regional Climate Model,V3.0)初边界资料,对RegCM3中常用的3种积云参数化方案Anthes-Kuo (AK)、Grell-Fritsch&Chappell (GFC)和MIT-Emanuel (MIT)方...     

Study of the Interaction between Biological Cells of Different Shapes and Sizes and Electromagnetic Fields Produced by Natural Phenomena

We carry out a study of the interaction between electromagnetic fields produced innature and cells with no structure but with different shapes and sizes, considered asapproximations of those observed in the human body. Magnetic fields produced byvarious atmospheric and geomagnetic phenomena are compared with the fieldsgenerated by the cells themselves. Working with frequencies up to 10⁵ Hz, we found that in most cases lightning is the natural phenomena capable of producingfield intensities comparable to those generated by the cells. As a first approximationwe assume that a cell might be affected only if a field of intensity comparable to thecell's field is present. Oscillating fields of less intensity and their harmonics can involveresonant interactions with the cells, however this situation is not considered here. Under the approximation of our study we found that the size and the shape are parameters of paramount importance: lightning represents a natural hazard only for the largest cells, while the quadrangular cells are not affected by any of the natural phenomena considered here.     

X射线荧光光谱法在耐火材料成分分析中的应用

采用熔融法制样,用X射线荧光光谱法对耐火材料中的Na2O、MgO、Al2O3、SiO2、K2O、CaO、TiO2、Cr2O3、MnO、Fe2O3、ZrO2、HfO2组分进行测定,使用康普顿散射线作内标和经验系数法校正基体效应,经标准物质检验与标准值吻合,大部分组分的RSD<5%(n=10)。