THE USE OF A RATIO METHOD AS AN ALTERNATIVE TO CONSTRAINED DECONVOLUTION

This paper will consider the use of an iterative ratio technique called Gold's ratio method as an alternativeto iterative constrained deconvolution methods for the restoration of overlapped and noisychromatograpic peaks.The study will consist of first describing the technique and then evaluating itsperformance with respect to Jansson's deconvolution procedure.A Hewlett-Packard 5890A gaschromatograph will be used to generate most of the test data.The evaluation criteria will includeconvergence rates,peak area errors and variances,retention time variances and noise performance.     

光纤光栅地震检波器结构设计与性能仿真研究

地震检波器是近年来石油勘探领域向前发展的一项瓶颈技术。本文基于光纤光栅的传感特性设计了不同结构的光纤光栅地震检波器，借助于有限元分析软件对光纤光栅地震检波器的传感特性进行了仿真研究，并分析了一些重要参数如光纤光栅波长、质量块的大小和光纤的长度等对地震检波器性能的影响规律，给出了不同结构的特性参数。本文研究结果对光纤光栅地震检波器的实用有一定的参考价值。     

Formation of reduced carbonaceous matter in basalts and xenoliths: reaction of C-O-H gases on olivine crack surfaces

It has been suggested that the formation of reduced carbonaceous matter in basalts and mantle xenoliths occurs by heterogeneous reaction of volcanic gas on fresh, chemically active crack surfaces produced by thermal stresses during eruption and cooling. This hypothesis is supported by experiments at 400-800 degrees C on ?010? surfaces of San Carlos olivine exposed to C-O-H gases generated by the decomposition of oxalic acid and oxalic acid dihydrate. Carbonaceous films form readily on these surfaces and achieve thicknesses comparable to those observed in natural samples (a few nanometers) in a matter of minutes. At relatively oxidizing conditions, the carbonaceous films consist principally of C-C and C-H bonded species with lesser amounts of C-O bonded species. At relatively reducing conditions, the carbonaceous films consist of subequal amounts of C-C/C-H, C-O, and metal-C species. Aliphatic and aromatic hydrocarbons and other thermally labile organic species are associated with carbonaceous films in some natural samples but none were detected in experimental samples from this study, leaving open the question of abiotic synthesis of organic matter on crack surfaces in basalts. Regardless, it is clear from the preliminary experiments reported here that crack surfaces in olivine (and probably other silicate minerals and glasses) are capable of stabilizing compounds that otherwise would not be stable in cooling lava.     

Southwest China and Southeast Asia: towards sustainability through cooperative development and management of international rivers *

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基于GIS的静态图式表达方法与制图表达方法的对比分析

针对GIS生成的地图产品脱离GIS地理空间数据,割裂地理要素与地图对象完整性,导致输出地图产品更新困难。结合制图单位实际生成需求,研究GIS静态图式表达和GIS制图表达;基于GIS制图模板和GIS符号库,采用C#+ArcEngine编程技术,实现GIS专题制图系统。系统具有GIS静态图式渲染功能和GIS制图表达功能,并以某区域专题制图项目为例,对比分析不同方式专题制图效果。结果表明基于地理空间数据规则的地图制图表达技术能够兼顾GIS和地图制图对数据的不同要求,可快速完成地图制作,部分解决传统上必须通过大量人工编辑才能够完成的制图任务,一定程度提高工作效率。     

对流干扰下的重力分异——基性岩侧向分带及矿化的主要机制

在基性—超基性岩中,特别是那些含矿岩体,常常发育有原生的侧向分带,传统的重力分异理论无法用原地分异机制对这一现象进行合理解释;新的硫化物成矿模型同样不能令人信服。我们在对重力结晶分异的研究中发现,对流干扰下的重力结晶分异可以形成侧向分带。研究采用动力学分析的方法,深入了解对流干扰下岩浆重力分异作用中的颗粒行为。在动力学分析中,考虑了前人研究中普遍忽略的伯努利效应。研究表明,伴随着快速对流干扰的岩浆重力结晶分异可以产生侧向分离效应,使颗粒趋于在侧壁附近快速堆积。侧分离效应和侧壁冷却效应一起迫使循环向热流上升中心方向后退,形成侧向分带岩石。由于对流通常只发生在岩浆侵位后结晶分异的早期高温阶段,与铜镍硫化物熔离的阶段相吻合,因此,铜镍硫化物的矿化通常与对流干扰下的重力分异密切相关。最后以一个实例解释侧向分带和成矿作用的形成机制。研究成果突破了传统关于重力分异的认识,为深入认识岩浆演化及指导找矿提供新的思路。     

Do a bit more with convolution

Convolution is a form of superposition that efficiently deals with input varying arbitrarily in time or space. It works whenever superposition is applicable, that is, for linear systems. Even though convolution is well-known since the 19th century, this valuable method is still missing in most textbooks on ground water hydrology. This limits widespread application in this field. Perhaps most papers are too complex mathematically as they tend to focus on the derivation of analytical expressions rather than solving practical problems. However, convolution is straightforward with standard mathematical software or even a spreadsheet, as is demonstrated in the paper. The necessary system responses are not limited to analytic solutions; they may also be obtained by running an already existing ground water model for a single stress period until equilibrium is reached. With these responses, high-resolution time series of head or discharge may then be computed by convolution for arbitrary points and arbitrarily varying input, without further use of the model. There are probably thousands of applications in the field of ground water hydrology that may benefit from convolution. Therefore, its inclusion in ground water textbooks and courses is strongly needed.     

相图对广西栗木花岗岩斑晶及起源岩浆的热力学形成条件的分析

与压力、温度、源岩成分、部分熔融程度有关的岩浆起源量化分析是花岗岩研究的难点。以广西栗木第二阶段花岗岩为研究对象,在岩相学及晶体类型分析的基础上,选择熔体晶体群中的斑晶和小颗粒环带净边结构斜长石及自形石英等作为探讨花岗岩起源之初始岩浆的特殊晶体群,运用相图分析它们形成时的压力和温度,进而推导出初始岩浆形成时的压力约为0.43 GPa(相当于深约16km处的上地壳),开始熔融出岩浆的共结点温度约为720°,初始岩浆最终熔出温度略高于800°,源岩成分的基性程度Ab/An值大于7.8。研究还表明,选择的特殊晶体群没有经历岩浆上升途中的阶段性生长,并认为,对于钙长石含量低的An—Ab—Or—Q岩浆体系(An5%),斑晶条纹长石的成分能够反映花岗岩浆起源时的部分熔融程度。该研究克服了前人利用矿物化学成分计算只能得出岩浆侵位时结晶温度、压力而得不到部分熔融时的熔融温度和压力的缺点,可为花岗岩起源分析提供有益的参考。     

Evaluation of MODFLOW-LGR in connection with a synthetic regional-scale model

This work studies costs and benefits of utilizing local-grid refinement (LGR) as implemented in MODFLOW-LGR to simulate groundwater flow in a buried tunnel valley interacting with a regional aquifer. Two alternative LGR methods were used: the shared-node (SN) method and the ghost-node (GN) method. To conserve flows the SN method requires correction of sources and sinks in cells at the refined/coarse-grid interface. We found that the optimal correction method is case dependent and difficult to identify in practice. However, the results showed little difference and suggest that identifying the optimal method was of minor importance in our case. The GN method does not require corrections at the models' interface, and it uses a simpler head interpolation scheme than the SN method. The simpler scheme is faster but less accurate so that more iterations may be necessary. However, the GN method solved our flow problem more efficiently than the SN method. The MODFLOW-LGR results were compared with the results obtained using a globally coarse (GC) grid. The LGR simulations required one to two orders of magnitude longer run times than the GC model. However, the improvements of the numerical resolution around the buried valley substantially increased the accuracy of simulated heads and flows compared with the GC simulation. Accuracy further increased locally around the valley flanks when improving the geological resolution using the refined grid. Finally, comparing MODFLOW-LGR simulation with a globally refined (GR) grid showed that the refinement proportion of the model should not exceed 10% to 15% in order to secure method efficiency.