三种商品探空仪的对比研究

为购买自动的无线电探空仪及测风系统,我们对三种商用系统进行了比较。几年前曾进行过类似比较(测风系统除外),这次对测风、细微结构的分辨力及操作的方便性予以特殊的注意。     

BED SHEAR IN EVOLVING SCOUR AT A CYLINDER:A THEORETICAL APPROACH

ＢＥＤＳＨＥＡＲＩＮＥＶＯＬＶＩＮＧＳＣＯＵＲＡＴＡＣＹＬＩＮＤＥＲ：ＡＴＨＥＯＲＥＴＩＣＡＬＡＰＰＲＯＡＣＨＳｕｂｈａｓｉｓｈＤＥＹ１ａｎｄＳｒｉｊｉｂＫ．ＫＡＲ２Ａｂｓｔｒａｃｔ：Ｔｈｅｔｅｍｐｏｒａｌｖａｒｉａｔｉｏｎｏｆｓｈｅａｒｓｔｒｅｓｓ...     

第四纪红砂层的热释光年代测量——斯里兰卡海岸砂丘的研究实例

通常人们认为,占据湿热带海岸大片地区的红砂层年代是无法测定的。本文根据热释光法取得了这些沉积物绝对年龄的初步成果,同时讨论了热释光法应用在了解环境地球化学情况方面的重要性。有关斯里兰卡海岸地区研究的结果表明,该区70,000年以来海平面可能受到过区域地质构造运动的影响。根据在现场发现红砂中的具有几何图形的细石器来看,可认为其年龄约为距今25,000年,这表明它确实比到目前为止人们所认为的年龄更老。     

挪威西部Вjфrкedalen的变质榴辉岩矿物相之间的Sr交代和分离

在挪威西部片麻岩地区的(?)橄榄岩研究中,变质榴辉岩显示异常的Sr浓缩,在全岩分析中SrO最大为2.4％。在变质榴辉岩矿物中存在的最大Sr浓度是:斜长石9.6％ SrO,绿帘石8.5％,黝帘石7.4％斜黝帘石4.7％,杆沸石6.65％,磷灰石1.5％,葡萄石0.5％,榍石0.3％,角闪石0.2％以及Sr-长石22.6％。锶异常是由于榴辉岩在角闪岩化作用期间Sr带入而形成的。被带入的Sr的来源或许是邻近的角闪岩和在晚加里东期带入的。晶体化学研究表明,根据晶体化学现有的知识和痕量元素分布很可能能够预见在矿物相之间Sr的分布。     

混合式三维电磁模拟方法

在地球物理文献中对三维电磁问题讨论过有限的几种数值解。这些数值解是利用积分方程,有限元法或有限差分技术获得的。莱尼斯和乔尼斯(Lines和Jones,1973)以及雷戴等人(Reddy等,1977)分别应用有限差分和有限元技术提出了关于三维大地电磁     

ENCORE: the effect of nutrient enrichment on coral reefs. Synthesis of results and conclusions

Coral reef degradation resulting from nutrient enrichment of coastal waters is of increasing global concern. Although effects of nutrients on coral reef organisms have been demonstrated in the laboratory, there is little direct evidence of nutrient effects on coral reef biota in situ. The ENCORE experiment investigated responses of coral reef organisms and processes to controlled additions of dissolved inorganic nitrogen (N) and/or phosphorus (P) on an offshore reef (One Tree Island) at the southern end of the Great Barrier Reef, Australia. A multi-disciplinary team assessed a variety of factors focusing on nutrient dynamics and biotic responses. A controlled and replicated experiment was conducted over two years using twelve small patch reefs ponded at low tide by a coral rim. Treatments included three control reefs (no nutrient addition) and three + N reefs (NH4Cl added), three + P reefs (KH2PO4 added), and three + N + P reefs. Nutrients were added as pulses at each low tide (ca twice per day) by remotely operated units. There were two phases of nutrient additions. During the initial, low-loading phase of the experiment nutrient pulses (mean dose = 11.5 microM NH4+; 2.3 microM PO4(-3)) rapidly declined, reaching near-background levels (mean = 0.9 microM NH4+; 0.5 microM PO4(-3)) within 2-3 h. A variety of biotic processes, assessed over a year during this initial nutrient loading phase, were not significantly affected, with the exception of coral reproduction, which was affected in all nutrient treatments. In Acropora longicyathus and A. aspera, fewer successfully developed embryos were formed, and in A. longicyathus fertilization rates and lipid levels decreased. In the second, high-loading, phase of ENCORE an increased nutrient dosage (mean dose = 36.2 microM NH4+; 5.1 microM PO4(-3)) declining to means of 11.3 microM NH4+ and 2.4 microM PO4(-3) at the end of low tide) was used for a further year, and a variety of significant biotic responses occurred. Encrusting algae incorporated virtually none of the added nutrients. Organisms containing endosymbiotic zooxanthellae (corals and giant clams) assimilated dissolved nutrients rapidly and were responsive to added nutrients. Coral mortality, not detected during the initial low-loading phase, became evident with increased nutrient dosage, particularly in Pocillopora damicornis. Nitrogen additions stunted coral growth, and phosphorus additions had a variable effect. Coral calcification rate and linear extension increased in the presence of added phosphorus but skeletal density was reduced, making corals more susceptible to breakage. Settlement of all coral larvae was reduced in nitrogen treatments, yet settlement of larvae from brooded species was enhanced in phosphorus treatments. Recruitment of stomatopods, benthic crustaceans living in coral rubble, was reduced in nitrogen and nitrogen plus phosphorus treatments. Grazing rates and reproductive effort of various fish species were not affected by the nutrient treatments. Microbial nitrogen transformations in sediments were responsive to nutrient loading with nitrogen fixation significantly increased in phosphorus treatments and denitrification increased in all treatments to which nitrogen had been added. Rates of bioerosion and grazing showed no significant effects of added nutrients. ENCORE has shown that reef organisms and processes investigated in situ were impacted by elevated nutrients. Impacts were dependent on dose level, whether nitrogen and/or phosphorus were elevated and were often species-specific. The impacts were generally sub-lethal and subtle and the treated reefs at the end of the experiment were visually similar to control reefs. Rapid nutrient uptake indicates that nutrient concentrations alone are not adequate to assess nutrient condition of reefs. Sensitive and quantifiable biological indicators need to be developed for coral reef ecosystems. The potential bioindicators identified in ENCORE should be tested in future research on coral reef/nutrient interactions. Synergistic and cumulative effects of elevated nutrients and other environmental parameters, comparative studies of intact vs. disturbed reefs, offshore vs. inshore reefs, or the ability of a nutrient-stressed reef to respond to natural disturbances require elucidation. An expanded understanding of coral reef responses to anthropogenic impacts is necessary, particularly regarding the subtle, sub-lethal effects detected in the ENCORE studies.     

广东省某水电站上坝公路、进厂房公路地质灾害影响评估

通过对广东省某水电站公路两侧存在的地质灾害-滑坡进行稳定性分析,并结合区域地质情况对该电站上坝公路、进厂房公路两侧存在的地质灾害现状进行了评估;最后,对评估区进行了分区,同时针对不同分区提出不同的治理方案.     

特大地震大小的快速估计法

将根据初至地震P波的宽带记录(即在宽频范围内的记录)得出的体波震级m_B重新引入国际地震实践中能更快地估计大地震的大小。国际地震学与地球内部物理学协会(IASPEI)震级测定工作组做出的这一建议以及与未来震级测量标准相关的其他建议于2005年10月2～8日在智利召开的IASPEI大会上被IASPEI地震观测与解释委员会采纳。     

中国西南天山山前的晚新生代构造与地震活动

天山是研究现今陆内造山作用及过程、陆内变形、陆内强震及其预测等大陆动力学问题的理想实验场。西南天山和塔里木之间的新生代褶皱－逆断裂带基本上由一南冲弧形推覆构造系统和一向北反冲的构造系统组成，由北而南主要由以下4个运动学单元组成：（1）新生代复活的喀拉铁热克山－天山南脉古生代造山带，其快速变形和抬升可能起始于23－26Ma前，持续至13－16Ma前。（2）向南逆冲的西南天山前陆薄皮主冲断带，包括木兹杜克弧形薄皮推覆体和依柯冲断带，前者代表了向南薄皮逆掩的天山型岩系，地表主要表现为一系列的飞来峰群，在14Ma前曾有过大规模活动，最小缩短量约为20－35km，最小缩短速率为1．4－2．8mm/a；后者代表了向南叠瓦状薄皮逆冲推覆的前陆古生代基底（塔里木地台型沉积岩系）卷入构造，其西段在距今14Ma时曾有过强烈活动。两者共同组成了一复杂的双重构造；新生代地层也卷入变形。（3）喀什－阿图什弧形反冲褶皱－逆断裂带，由3排向北（天山）反冲的左阶雁列展布的第四纪地表滑脱褶皱组成，仅在大山口以西发育。该构造带形成于距今约1．4Ma以后。依什拉克喀拉乌尔断裂以南，博古孜河剖面的最小缩短速率约为5．8mm/a，翁库尔剖面的最小缩短速率约为8．6mm/a。（4）塔里木克拉通下盘块体，向北西方向缓倾，内部变形较小。里木块体西北存在明显的不均匀性，其学问基底高角度逆断裂和走滑断裂控制了盆地新生代沉积的厚度，导致西南天山前陆冲断带的地形地貌、地层、构造变形样式、变形时间以及变形缩短量沿走向的巨大差异性。迈丹－喀拉铁克断裂和阿图什断裂带均为岩石圈规模断裂，研究区的中强地震主要发生在这两条断裂带以及它们之间的西南天山前陆冲断带上。