河西走廊疏勒河流域地质灾害危险性现状评估方法的应用——以甘肃省河西走廊(疏勒河)农业灌溉暨移民安置综合开发建设项目8个移民社区及配套工程建设为例

依据“建设用地地质灾害危险性评估技术要求”、利用野外踏勘及相关资料,对“甘肃省河西走廊（疏勒河）农业灌溉暨移民安置综合开发建设项目8个移民社区及配套工程”进行地质灾害危险性现状评估。结果认为：评估区发育和分布的地质灾害类型有土壤盐渍化、风蚀沙埋和洪水冲蚀。现状评估结果：土壤盐渍化和洪水冲蚀危险性均小;风蚀沙埋有1处危险性中等,其它危险性小。     

弯道超高法在泥石流流速计算中的应用——以四川省汶川县G317国道磨子沟泥石流为例

选取四川省汶川至马尔康公路线的磨子沟作为试验对象,采用弯道超高法推算其泥石流流速。进而可以计算出该次泥石流的平均流量,为公路的改建工程提供设计依据。经过实地调查,用此方法计算磨子沟2005年8月17日暴发的泥石流流速为4.4m/s。同其他流速方法计算的结果相比较,前者值偏大,且偏向于工程安全值。弯道超高法可以解决泥石流观测的局限性和泥石流发生的不可重复性。此方法简便易行,对泥石流防治工程具有一定的实用价值。     

Chlorophyll modulation of mixed layer thermodynamics in a mixed-layer isopycnal General Circulation Model — An example from Arabian Sea and equatorial Pacific

Western tropical Indian Ocean, Arabian Sea, and the equatorial Pacific are known as regions of intense bio-chemical-physical interactions: the Arabian Sea has the largest phytoplankton bloom with seasonal signal, while the equatorial Pacific bloom is perennial with quasi-permanent upwelling. Here, we studied three dimensional ocean thermodynamics comparing recent ocean observation with ocean general circulation model (OPYC) experiment combined with remotely sensed chlorophyll pigment concentrations from the Coastal Zone Color Scanner (CZCS). Using solar radiation parameterization representing observations that a higher abundance of chlorophyll increases absorption of solar irradiance and heating rate in the upper ocean, we showed that the mixed layer thickness decreases more than they would be under clear water conditions. These changes in the model mixed layer were consistent with Joint Global Ocean Flux Study (JGOFS) observations during the 1994-1995 Arabian Sea experiment and epi-fluorescence microscopy (EFM) on samples collected during Equatorial Pacific Ocean Climate Study (EPOCS) in November, 1988. In the Arabian Sea, as the chlorophyll concentrations peak in October (3 mg/m³) after the summer plankton bloom induced by coastal upwelling, the chlorophyll induced biological heating enhanced the sea surface temperature (SST) by as much as 0.6‡C and sub-layer temperature decreases and sub-layer thickness increases. In the equatorial Pacific, modest concentrations of chlorophyll less than 0.3 mg/m³ is enough to introduce a meridional differential heating, which results in reducing the equatorial mixed layer thickness to more than 20 m. The anomalous meridional tilting of the mixed layer bottom enhances off equatorial westward geostrophic currents. Consequently, the equatorial undercurrent transports more water from west to east. We proposed that these numerical model experiments with use of satellite andin situ ocean observations are consistent under three dimensional ocean circulation theory combined with solar radiation transfer process.     

Analogue study of particle segregation in pyroclastic density currents, with implications for the emplacement mechanisms of large ignimbrites

Abstract Analogue flume experiments were conducted to investigate the transport and sedimentation behaviour of turbulent pyroclastic density currents. The experimental currents were scaled approximately to the natural environment in three ways: (1) they were fully turbulent; (2) they had a very wide range of particle sizes and associated Rouse numbers (the ratio of particle settling velocity to effective turbulent eddy velocity in the current); and (3) they contained particles of two different densities. Two sets of surge‐type experiments were conducted in a 5 m long, water‐filled lock‐exchange flume at five different volumetric particle concentrations from 0·6% to 23%. In one set (one‐component experiments), the currents contained just dense particles; in the other set (two‐component experiments), they contained both light and dense particles in equal volume proportions. In both sets of experiments, the population of each component had a log‐normal size distribution. In the two‐component experiments, the size range of the light particle population was selected in order to be in hydrodynamic equivalence with that of the dense particles. Dense particles were normally graded, both vertically and downstream, in the deposits from both sets of experiments. The mass loading (normalized to the initial mass of the suspension) and grain size of the dense component in the deposits decreased with distance from the reservoir and were insensitive to initial total particle concentration in the currents. On the other hand, in the two‐component experiments, the light particles were extremely sensitive to concentration. They were deposited in hydrodynamic equivalence with the dense particles from dilute currents, but were segregated efficiently at concentrations higher than a few per cent. With increasing particle concentration, the large, light particles were carried progressively further down the flume because of buoyancy effects. Deposits from the high‐concentration currents exhibited reverse vertical grading of the large, light particles. Efficient segregation of the light component was observed even if the bulk density of the current was less than that of the light particles. In both sets of experiments, marked inflexions in the rate of downstream decline in mass loading and maximum grain size of the dense component can be attributed to the presence of two different particle settling regimes in the flow: (1) particles with Rouse numbers >2·5, which did not respond to the turbulence and settled rapidly; and (2) particles with Rouse numbers <2·5, which followed the turbulent eddies and settled slowly. The results are applied to the transport and sedimentation dynamics of pyroclastic density currents that generate large, widespread ignimbrites. Field data fail to reveal significant departures from aerodynamic equivalence between pumice and lithic clasts in three such ignimbrites: the particulate loads of some large ignimbrites are transported principally in turbulent suspensions of low concentration. In some ignimbrites, the well‐developed inflexions in curves of maximum lithic (ML) size vs. distance can be attributed to the existence of distinct high and low Rouse number particle settling regimes that mark the transition from an overcharged state to one in which the residual particulate load is transported more effectively by turbulence.     

交流变频调速CD-2B型岩心钻机的研制

介绍了交流变频调速CD－2B型岩心钻机研制情况，技术参数，主要特点及型式检验，生产试验等情况。     

可调滞回模型的磁流变阻尼器及其试验

本文在现在磁流变阴尼器性能研究的基础上，提出了可调滞回模型的磁流变阻尼器及其试验方法，并进行理论、试验及算例分析。首先，根据恒定电流下磁流变阻尼器的阻尼力滞力特性，利用磁流变材料特性的电流（即磁场）可控特点，建立了变电流下的阻尼力滞回模型；其次，在中通过电路板控制外加电流与装置变形间的函数关系，实现了变电流调节的阻尼力滞回模型；最后，将磁流变阻尼器与橡胶隔震装置结合，形成智能磁流变隔夺装置，并对一个单自由度隔震结构进行了数值仿真分析。     

Three types of pyroclastic currents and their deposits: examples from the Vulsini Volcanoes, Italy

This paper deals with ground-hugging, gas–pyroclast currents from explosive volcanic eruptions and their deposits. Key field observations and laboratory determinations are proposed to relate specific deposit types with flow regimes and particle concentration in the transport and depositional systems. Three relevant flow scenarios and corresponding deposit types have been recognized from a survey of pyroclastic successions of the Vulsini Volcanic District (central Italy): (1) dilute, turbulent, pyroclastic currents producing normally or multiply graded beds by direct suspension sedimentation; (2) concentrated bedload regions beneath suspension currents, depositing inversely graded beds by traction carpet sedimentation; (3) self-sustained, high particle concentration, laminar, mass flows developing massive, poorly sorted bodies, with opposite grading of coarse lithic and pumice clasts, overlying fine-grained, inversely graded, basal layers. Main distinguishing criteria include the occurrence and pattern of clast grading, clast–thickness relationships, grain size, ash matrix componentry and pyroclast size–density relationships. Downcurrent and temporal transitions among identified flow scenarios are likely to occur for changing energy conditions and gas–pyroclast ratio both on regional and local scales. The nature and efficiency of magma fragmentation, volatile content, conduit geometry (which determine the characteristics of the erupted mixture and possible lateral blast component at the vent), and the angle of incidence of the column collapse, are suggested as the main factors controlling the generation of one type over the other at flow inception. Dilute, fine-grained, overpressured eruption clouds are thought to favor the formation of low particle concentration turbulent currents. Column collapse over slightly inclined volcano slopes, causing a high degree of compression of the collapsing mixture and of gas expulsion, would favor the generation of high particle concentration pyroclastic currents.     

由GPS观测结果推导中国大陆现今水平应变场

以中国大陆及周边近400个GPS测站的水平运动速率为基础，给出了现今地壳水平应变场结果表明:①中国大陆水平应变为西强东弱，剪应变数值大于正应变数值(绝对值)，应变量级一般为10-8/a，局部区域达到10-7/a，但应变分布不均匀；②南北向应变最突出的部位为中国西南部西段的喜马拉雅条带、西北部的36N~42N段及柴达木断块的北缘；③东西向应变西边缘变化最大．此外，由西向东还具有正负交替的变化特征；④REN(东-北向剪切应变)与Rmax(最大剪切应变)数值较大的区域分别是喜马拉雅条带、西北部的36N～42N段、柴达木断块的西部、川滇菱形块体，以及阿拉善、祁连及塔里木断块的交界区；⑤青藏块体周边以面收缩为主，内部则以面膨胀为主．其以北的地区以面收缩为主．西界数值最大，东部数值最小(除燕山构造带外)；⑥西部西区主压应变为南北向，主张应变为东西向．西部东缘区主压应变为近东西向，主张应变为近南北向．川滇菱形块体主应变的方向发生了很大的变化，北部地区为东西压南北张，南部地区则恰好相反；⑦中国大陆的应变模式可能是断块模式与连续模式的组合．此外，小尺度优势应变可能是剪切应变．造成上述结果除与印度板块的碰撞及边界耦合有关外，还与深部物质的活动及地壳介质的物性有密切的关系．必须指出，由于GPS测站在空间上分布的不均匀性，那么，由此而来的应变场，其应变尺度也不一样．      

环电流区中性原子观测特性模拟研究

为了给双星计划中性原子(ENA)探测仪的研制提供可靠 的理论依据，并为未来中性原子探测数据的分析及研究做好准备，针对双星轨道初步模拟计 算了双星ENA探测仪对磁暴时中性原子的观测特性. 建立了磁暴主相期间环电流离子分布的 一 个近似理论模式，并模拟计算了极轨卫星在极区上空、赤道面以及其他位置上对不同强度磁 暴主相期间环电流区ENA空间角分布及能谱的观测结果. 研究表明，存在环电流区方向和南 北极区环电流粒子沉降带两个中性原子强度极大区域；磁暴越强烈，注入区高度越低，环电 流区观测到的ENA通量越高；处于有利位置的ENA探测器可分辨注入区内边界或注入前沿；EN A探测器能够分辨环电流带离子分布的不均匀性；由于离子交换截面的差异，H，O，He 3种E NA的能谱分布不同；在10～80keV能谱范围内通量较强，易于观测；环电流区H，O两种ENA 通 量较强，有利于观测；而环电流区He ENA通量很弱，不易于观测. 模拟计算研究表明，双星 极轨卫星能够对环电流区ENA进行有效探测；低纬轨道上的ENA探测器也能够对环电流区ENA 进行一些观测；ENA探测器的研制应重视低、中能量范围ENA的探测.     

数字化地震遥测台网不间断供电系统研制

本文介绍一种适用于数字化遥测地震台网的不间断供电系统，它具有交直流不间断切换，输出满足数据采集系统及数据传输设备所需的各种电压要求，并能对备份蓄电池自动恒流、恒压转换充电及过放电保护，冗余量大、可靠性高。解决了无人值守遥测地震台的供电问题。对其它数字设备也有广泛的应用价值。