Characteristics of the changes in tropical cyclones influencing the South Korean region over the recent 10 years (2001–2010)

Through the investigation of tropical cyclone (TC) characteristics related to climate change, this study found that the frequency of TCs occurring over the Western North Pacific has recently decreased slightly, while their average intensity has increased. The number of overall TCs that passed within the vicinity of South Korea has also been reduced, but the number of strong typhoons in the area, those with maximum wind speeds of more than 44 m/s, has significantly increased. These changes are closely related to the following phenomena. (1) The average genesis region of TCs that influence South Korea has moved eastward. Accordingly, the TCs tend to strengthen as they move westward for long distances along the Intertropical Convergence Zone (ITCZ) trade easterlies and the southern boundary of the North Pacific Subtropical High (NPSH). (2) The NPSH and Asia Monsoon trough, which are known to affect TC tracks, have extended to the northwest and southeast. This has caused TCs that travel to higher latitudes and curve back toward the Korean Peninsula to become more frequent. (3) TCs have approached the Korean Peninsula without hitting land. In addition, the sea surface temperature became higher than it was before. These factors have caused TCs to maintain their strength or become stronger than before.     

A Periodicity Analysis of the Light Curve of 3C 454.3

We analyzed the radio light curves of 3C 454.3 at frequencies 22 and 37 GHz taken from the database of Metsahovi Radio Observatory, and found evidence of quasi-periodic activity. The light curves show great activity with very complicated non-sinusoidal variations. Two possible periods, a very weak one of 1.57±0.12 yr and a very strong one of 6.15±0.50 yr were consistently identified by two methods, the Jurkevich method and power spectrum estimation. The period of 6.15±0.50 yr is consistent with results previously reported by Ciaramella et al. and Webb et al. Applying the binary black hole model to the central structure we found black hole masses of 1.53×109M⊙and 1.86×108M⊙, and predicted that the next radio outburst is to take place in 2006 March and April.     

Spatial distribution of stream sediment pollution by toxic trace elements at Tourtit and Ichoumellal abandoned mining areas (central Morocco)

This study presents a diagnostic of the current state of 114 stream sediment samples by their elemental concentrations (Sb, Cd, Pb, As, Cu, Zn, Ni, Cr, and Hg), collected from Ighardayane upstream on an area of 15 km² located at the SE part of central Morocco where Tourtit and Ichoumellal, two abandoned mining sites of Stibnite, are located. Several approaches were used to model the analysis (i) enrichment factor (EF), (ii) sediment pollution index (IPS), (iii) probable effect concentration-quotients (PEC-Qs), and (iv) potential ecological risk index (PERI). Results show highly contaminated areas around the old mining sites by Sb As, Pb, and Cd. Cadmium and lead show 86.9 and 12.29% (respectively) of trace element pollution according to sediment pollution index. Twenty-eight percent of the sampled area is potentially highly toxic because of the presence of Hg, Pb, and Cd. The very similar distribution of pollution and toxicity of most analyzed trace elements may originate from the same source, which corresponds to mining wastes where we recorded the highest pollution and toxicity degrees. This environmental issue represents the combination of Tourtit and Ichoumellal anthropic sources responsible of Sb, As, Pb, and Cd release and a probable natural source of Hg “that needs a further study,” which contribute in the degradation of an aquatic ecosystem of the same area. Therefore, both ecotoxicological analysis and stream sediment quality management should be carried out to control this aquatic ecosystem toxication.     

基于PMCS图像数据的雨滴微物理特征研究

基于2015年降水微物理特征测量仪(PMCS)在南京地区获得的3次降水过程的雨滴图像资料,利用图像处理算法得到雨滴形状、尺度、轴比、倾斜角、垂直速度等特征参量,研究了雨滴的微物理特征空间分布规律。结果表明:直径较小的雨滴轮廓呈圆环状,随着粒子直径增加,雨滴轮廓呈现出椭圆形和底部扁平顶部凸起状。PMCS测得的雨滴轴比—直径拟合关系同经验模型相比误差较小,雨滴轴比概率分布呈现高斯分布特征。雨滴倾斜角分布于0°两侧,方差为15.9°,小雨滴倾斜角受湍流影响较大,摆动范围较大。雨滴垂直速度随直径增大而增大,垂直速度拟合曲线同Atlas速度经验模型分布较为一致。     

Influence of the Arctic Oscillation on the TC activity around Taiwan

This study discovered that strong positive correlations exist between the frequency of tropical cyclones (TC) during the summer around Taiwan and the Arctic Oscillation (AO) during the preceding March to May period. In positive AO years, during the preceding spring to summer period, anomalous cyclone and anomalous anticyclone were strongly developed at low and middle latitudes, respectively. Because of such a distribution of pressure system, in Taiwan, Korea, and Japan during the positive AO years, anomalous southeasterlies, which play the role of anomalous steering flows in transferring TCs to these regions, were strengthened. On the other hand, in southern China and the Indochina Peninsula during the positive AO years, anomalous northwesterlies, which prevent the transfer of TCs to these regions, were strengthened. Moreover, such a distribution of pressure system strengthening during the positive AO years led TCs to occur, move, and recurve more eastward in the western North Pacific in positive AO years as compared with the negative AO years. Contrarily, during the negative AO years, TCs showed the tendency to pass over the South China Sea from the Philippines and move west toward southern China and the Indochina Peninsula. Eventually, the intensity of TCs in these years was lower than that of TCs in positive AO years due to the topographic effects from a high TC passage frequency in mainland China.     

唐山地震高烈度区场地条件对震害的影响

本文在详细调查了唐山地震高烈度区后认为,在10度以上的高烈度区内,不同地段的震害有明显的差异,其中场地条件(地基土、局部地形等)起着很重要的作用。文中还对煤田采空沉陷区边缘地带的震害进行了初步分析。     

Brightness fluctuations in the K-line wings

A power-spectrum and cross-spectrum analysis has been made of measurements of temporal fluctuations of intensity observed in the K-line wing (2.07 Å from line center) and of simultaneous measurements of temporal fluctuations of Doppler displacement of the cores of 3931.122 Fe i and 3933 Ca ii (K₃). The measurements were made in a quiet region near the center of the Sun's disk. We find that the average power spectra of the intensity fluctuations have two significant peaks of about equal strength: one at 0.0033 Hz (300-s period); and one at about 0.001 Hz (1000-s period). The average rms value of these intensity fluctuations is 0.0435±0.0082. Maximum brightness comes before maximum violet displacement of the Fe i line. The mean of the best determined phases is 137° and of all the data 108°. At those places on the Sun where the 300-s oscillations can be identified in the k₃ core, the Doppler displacement of the Fe i line leads that of the K₃ core by a mean phase angle of 27°.     

仙王座β型变星ν Eri的测光,分光观测及脉动模式的分析

本文给出了１９９１年１１月在北京天文台兴隆观测站对仙王座β型变星ν Ｅｒｉ进行的ｂ，ｙ波段光电测光结果，及１９９１年１２月在云南天文台观测获得的高分辨、大色散的ＳｉＩＩＩ线附近区的ＣＣＤ光谱，根据光变的多重周期分析结果，计算和分析了ν Ｅｒｉ的理论脉动模式，并以高分辨的ＳｉＩＩＩ线轮廓为例，分析了该星的谱线轮廓变化并计算了谱线的半宽，等值宽度以及视向速度。     

Use of Tunisian raw clay to remove dye from aqueous solution

This paper presents the first attempt to investigate the potential of Tunisian palygorskite-rich clay (Pal-clay) on the effectiveness of a textile dye “Direct orange 34” (DO34) removal. Important parameters which affect adsorption, such as initial solution pH, contact time, adsorbent mass, initial dye concentration, and temperature, were investigated. The raw Pal-clay was characterized using X-ray diffractometer (XRD), X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR), cation exchange capacity (CEC), specific surface area (SSA) analysis, and point of zero charge (PZC) determination. The results showed that the Pal-clay has a high selectivity for DO34 and had maximum removal efficiency reaching up to about 91 %. The highest adsorption capacity was obtained at 25 °C and pH of 2. The dye uptake process fitted well to the pseudo-second-order kinetic expression and was best described by the Langmuir and Freundlich isotherms. Intra-particle diffusion studies showed that the adsorption mechanism was not exclusively controlled by the diffusion step and was more likely to be governed by external mass transfer. Thermodynamic parameters such as change in free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) were also calculated. The parameters revealed that the adsorption of dye by the raw clay is spontaneous and exothermic. The results indicate that the Pal-clay has a moderate adsorption capacity towards anionic dye.