Optical Spectra Evolution of BL Lac Objects

Many quasi-simultaneous optical observations of nine BL Lac objects are obtained from literature. We study the relationship between the optical spectral index and the luminosity of BL Lac objects, and are tempted to exploit spectral evolution in the optical frequency ranges. Our results show that: (i) The optical spectra index of the low-frequency peaked BL Lac objects (LBLs) is steeper than the high-frequency peaked BL Lac objects (HBLs); (ii) The spectra tend to be softer when the source becomes brighter for LBLs and the intermediate BL Lac objects (IBLs) (i.e., bluer-when-brighter), and the spectra of HBLs does not vary when the brightness of HBLs changes. Possible explanations are briefly discussed for this phenomenon.     

曲阳大理石矿岩溶发育机制研究

曲阳大理石矿发育的红色风化壳大都是第四纪第Ⅰ、Ⅱ间冰期湿热气候条件下溶蚀与风化作用的结果,形成硅酸—铁型风化壳。风化壳中红粘土化学成分R2O3（Al2O3+Fe2O3）含量达24.33—31.88％。当降水或地表水的垂直下渗,水中游离的氢离子与红粘土中固相的铝相互转化交换的愈多,红粘土的氢离子浓度愈大,pH值愈小其酸度愈大,溶蚀性增强。沿红粘土和大理岩接触面产生溶蚀作用,形成石芽、溶沟、溶槽、溶痕等岩溶形态,并在它们的表面保留有红粘土痕迹。 CAJ下     

Wavefield simulation in porous media saturated with two immiscible fluids

Wavefields in porous media saturated by two immiscible fluids are simulated in this paper. Based on the sealed system theory, the medium model considers both the relative motion between the fluids and the solid skeleton and the relaxation mechanisms of porosity and saturation (capillary pressure). So it accurately simulates the numerical attenuation property of the wavefields and is much closer to actual earth media in exploration than the equivalent liquid model and the unsaturated porous medium model on the basis of open system theory. The velocity and attenuation for different wave modes in this medium have been discussed in previous literature but studies of the complete wave-field have not been reported. In our work, wave equations with the relaxation mechanisms of capillary pressure and the porosity are derived. Furthermore, the wavefield and its characteristics are studied using the numerical finite element method. The results show that the slow P3-wave in the non-wetting phase can be observed clearly in the seismic band. The relaxation of capillary pressure and the porosity greatly affect the displacement of the non-wetting phase. More specifically, the displacement decreases with increasing relaxation coefficient.     

渤海湾西岸晚第四纪海相地层划分及地质意义

BT113孔和BT114孔是位于渤海湾西岸地区的2个80 m全取心钻孔。通过对钻孔岩心的岩性、沉积构造及生物组合等特征分析,结合AMS¹⁴C和OSL（光释光）测年结果,揭示中更新世晚期以来本地区主要发育3个海相地层：自下而上为中更新统上部的第三海相地层（简称“海三”）、上更新统的第二海相地层（简称“海二”）和全新统的第一海相地层（简称“海一”）,指示中更新世晚期以来研究区发生的3次主要海面波动。与全球海面变化曲线对比,海三,海二和海一分别发育于MIS（深海氧同位素阶段）7、MIS5和MIS1的高海面时期,说明渤海湾西岸中更新晚期以来地层记录的海面变化趋势与全球变化一致。与前人的传统认识不同,认为受全球海面及渤海海峡地貌共同影响,MIS3时期研究区并未发生大范围海侵。通过多个钻孔的对比分析,3个海相地层在渤海湾西岸地区的分布较广,具有良好的可对比性,不同钻孔之间同一海相地层的高程和厚度的较大差异指示本地区在晚更新世期间发生较强的差异性沉降活动。     

NLS EQUATION OF INTERNAL WAVES IN WEAKLY STRATIFIED OCEAN

The NLS (Non-Linear Schr(?)dinger) equation of internal waves in a wekly stratified ocean is der-ived in phase coordnates in terms of the RPM (Reductive Perturbation Method). It was shown thatwhen AB>0 there exist modulation forms of envelope soliton and dn, and tha when AB<0 there arethree modulation forms dark soliton, sn and cn. Only if K~2>B/A(?) . the side-band perturbation is stable,otherwise unstable. For the stable side-band perturbation there ekisis a modulation form of MdV soliton.     

长白山国家级自然保护区旅游与环境可持续发展研究

举世闻名的长白山国家级自然保护区近年随着旅游事业的发展,因环境管理措施不力等原因,面带来的了定的环境污染与较明显的生态破坏。协调好旅游开发与环境保护的唯一出路是坚持可发展的原则,为此,必须建立完整技术与管理体系,并因地制宜采取一系列相应的对策与措施。     

安徽铜陵朝山金矿床稳定同位素、稀土元素地球化学研究

朝山金矿床位于安徽铜陵狮子山矿田，属于矽卡岩型金矿床，侵入岩体为白芒山辉石二长闪长岩体。成矿过程包括矽卡岩阶段、石英-硫化物阶段和碳酸盐阶段3个主要成矿阶段。文章通过对朝山金矿床的氢、氧、碳、硫、硅同位素组成和稀土元素地球化学特征的研究，探讨成矿溶液中水、碳、硅和硫的来源以及成矿溶液的演化问题。研究表明，成矿热液早期以岩浆热液为主，随着成矿过程的进行，加入的大气降水比重越来越大，到晚期可能主要以大气降水为主。该矿床矿石中方解石的碳、氧同位素组成与矿区大理岩的碳、氧同位素组成明显不同，其δ^13 Cv-PDB、δ^18OV-SMOW值分别为-4．5～-5．3‰、13．9～14．0‰，与岩浆作用形成的CO2的碳、氧同位素组成一致，表明矿石中方解石的碳、氧来源于岩浆作用。硅和硫具深部岩浆或岩浆热液来源的特点。     

Tremendous change of the earth surface system and tectonic setting of salt-lake formation in Yuncheng Basin since 7.1 Ma

The Yuncheng salt lake has formed under the setting of stepped subsidence of fault-blocks from the north to the south in Yuncheng Basin. In the phase of red clay accumulation during 7.1-3.6 Ma, the size of palaeo-lake was larger than the present salt lake, and palaeo-monsoon had formed. At 3.6 Ma, the northern basement in the basin raised abruptly due to the radiative effect of Qinghai-Tibet Plateau uplifting, and palaeo-lake was contracting southwards. At ca. 2.6 Ma ancient river flowed into the northern part of the basin. During ca. 2.0-1.9 Ma aerolian effect strengthened and loess started to accumulate on the most part of the basin. Since ca. 1.8-1.0 Ma the subsidence of the lake fault-block has been speeding up abruptly. As under the natural hydrogradient the salt lake received enough groundwater supply, and the rate of loess accumulation in the lake area was lower than that of subsidence of the lake fault-block, the lake could be preserved and becomes the only modern lake on Chinese Loess Plateau. Four large strengthening change records of the monsoon were found in the lake sequence of 5.8-1.9 Ma B.P.     

从区域地理特点审视西部大开发战略

中国西部地区生态环境十分脆弱，又是大江大河的河源地，如果发生不利的开发行为，西部大开发可能导致环境的大污染，生态的大破坏和不可再生资源的全面枯竭，最终威胁到西部人的生存和发展。因此，制定正确的开发战略至关重要。利用地理学原理，客观地分析西部经济发展的限制因素和比较优势，依据非均衡的增长极开发理论，探讨如何推进西部小城镇建设，培育具有西部比较优势的特色农业支柱产业，以信息化带动工业化，实现西部资源的综合利用，使城市增长极和产业增长极成为动广大中西部地区经济增长的不竭动力。