流域景观功能网络构建及应用——以台湾乌溪流域为例

选择生态及城市功能并重的台湾乌溪流域,在乡镇行政单元的基础上,利用耗费距离模型将景观功能网络落实于实际的空间单元。透过网络节点间的通达性分析可知,乌溪流域的景观功能网络中以城市功能网络结构较佳,城市子节点多环绕于城市功能中心,功能的输出与传递有较高的效益;而生态功能网络节点间通达性差异并不显著,唯作为一级及二级功能节点的红香、高美湿地等位置孤立、通达性较差,需就其功能向外传输路径进行优化,并提升二载山及北坑子等重要联系节点的生态功能强度。     

混合发酵产甲壳素酶发酵条件优化及粗酶部分性质研究

利用甲壳素作为唯一碳源从土壤中筛得的真菌d,与细菌s混合发酵,对其最适产酶条件、所产甲壳素粗酶的制取以及粗酶性质进行初步研究。结果表明,混合发酵产酶的能力与单独发酵相比显著提高,混合发酵最适培养基组分为(×10~(-2) g/mL):尿素1.0,K_2HPO_4 0.07,KH_2PO_4 0.03,MgSO_4 0.05,酵母粉0.5,甲壳素1.0,pH 5.5,接种量2%(体积分数),32℃,130 r/min培养72 h,500 mL锥形瓶培养基装量为100 mL。经过优化,发酵液中甲壳素酶活力从0.73 U/mL提升到1.19 U/mL。通过对粗酶性质初步的研究,发现该酶有较好的稳定性。     

低山丘陵区土壤侵蚀生态工程治理模式及优化配置——以四川省宣汉县拱桥河流域为例

立足于四川省宣汉县拱桥河流域4.3 km2的柏树河村,在小区观测的基础上,提出了5种低山丘陵区土壤侵蚀生态治理模式。根据小流域生态系统的特点,应用多目标优化理论,按不同的治理模式进行了生态工程治理分区,治理措施达到了优化配置,从而使小流域既成为一个水土保持防护体系单元,又成为发展商品生产基地的经济单元,创造人与自然和谐相处的生态环境,为南方丘陵地区小流域提出了一套合理的生态工程治理模式。     

An algorithm for mesh simplification applied to fracture hydrology

Numerically generated discrete fracture networks are used to simulate the flow of water through rock fractures. The fractures are modeled as random assemblages of conductive elements in a nonconductive matrix. Because large numbers of fractures often are needed to represent fractured rock adequately, minimizing the required computer time and memory is crucial. For steady-state flow, any portion of the mesh that is linked to the rest of the mesh by only one point is a dead end and does not contribute to water flow. The removal of such dead-end clusters simplifies the mesh and therefore speeds up computation, without changing its response. An algorithm for removing these dead ends is described in detail. Its effectiveness is discussed with regard to the connectivity of a network.     

A computerized geologic mapping system based on logical models of geologic structures

In this article we describe the basic framework of the computerized geologic mapping system cigma. The system, whic is based on a mathematical formulation of geologic concepts, consists of the following six subsystems: (1) input of geologic data set; (2) inference of stratigraphic sequence; (3) construction of logical models of geologic structures; (4) determination of three-dimensional geologic boundary surfaces; (5) construction of three-dimensional solid model of geologic structures; and (6) graphical presentation. Geologic structures are summarized in several tables called logical models of geologic structures. Each model is constructed automatically from input data on structural relations between geologic bodies. The model interprets the data automatically to create data files necessary to determine the shapes of geologic boundaries; it also provides a threedimensional solid model of geologic structures referring to the shapes of boundaries. As a prototype, we introduce two types of contacts corresponding to conformity and unconformity into the logical model and show that it is possible to draw a geologic map automatically. More complex geologic structures can be introduced into the geologic mapping system through further formulation of geologic structures.     

Determination and interpretation of preferred orientation with texture goniometry: An application of indicators to maximum entropy pole- to orientation-density inversion

The probability density function of orientations of crystals generally cannot be measured directly without destruction of the specimen. Therefore it is usual practice to sample pole density functions of several crystal forms in diffraction experiments with a texture goniometer. Determining a reasonable orientation density function from experimental pole density functions is then the crucial prerequisite of quantitative texture analysis. This mathematical problem may be addressed as a tomographic inversion problem specified by the crystal and statistical specimen symmetries and the properties of the diffraction experiment. Its solution with maximum entropy preferred orientation portion and maximum uniform portion is proposed because it yields the most conservative orientation density function with systematically reduced correlation effects, thus avoiding artificial texture ghost≓ components caused by the specific properties of the diffraction experiment.     

中国近百年夏季雨量场及雨带类型恢复研究

文章将气象要素场转化为秩序统计量场,用ＥＯＦ迭代方案进行气象要素场的恢复研究．利用全国４２个站点１９５１～１９９５年夏季（６～８月）雨量场资料对１９０１～１９５０年夏季雨量场进行了恢复,并在此基础上用Ｂａｙｅｓ判别法对雨带类型进行了恢复．检验表明,所恢复的资料是可靠的．     

Optimal Gridding Process for GMI Brightness Temperature Using the Backus-Gilbert Method

Satellite microwave instruments have different field of views (FOVs) in different channels. A direct average technique ("direct method") is frequently used to generate gridded datasets in the earth science community. A large FOV will measure radiance from outside the area of a designated grid cell. Thus, the direct method will lead to errors in a measurement over a grid cell because some pixels covering areas outside of the cell are involved in the averaging process. The Backus-Gilbert method (BG method) is proposed and demonstrated to minimize those uncertainties. Three sampling resolutions (6.5 km × 6.0 km, 11.5 km × 6.0 km, 13.0 km × 6.0 km) are analyzed based on the scanning characteristics of the Global Precipitation Measurement (GPM) Microwave Imager (GMI) 18.9-GHz channel. Brightness temperatures (TBs) at 0.5 km × 0.5 km resolution over eastern China are used to obtain synthetic 18.9-GHz TBs at the three sampling resolutions. The direct and BG methods are both applied to create a 25 km × 25 km gridded dataset and their related uncertainties are analyzed. Results indicate the error variances with the direct method are 3.00, 3.68 and 4.99 K2 at the three sampling resolutions, respectively. By contrast, the BG method leads to a much smaller error variance than the direct method, especially over areas with a large TB gradient. Two GMI orbital measurements are applied to verify the BG method for gridding process is reliable. The BG method could be utilized for general purpose of creating a gridded dataset.     

区域旅游系统空间结构的模式与优化 ——以西安地区为例

本文在分析国内外区域旅游空间结构研究基础上,以西安地区为例,探讨了区域旅游系统空间结构的模式和优化问题。首先,在分析哈格特空间结构模型和冈恩的目的地地带模型的基础上,重新构建了由旅游目的地区域、旅游区、节点、区内路径、入口通道和客源地市场等六个要素构成的旅游系统空间结构模型;并按照旅游开发的时序关系,阐述了该模型在不同阶段的演变形态和特征。其次,实证分析表明：西安旅游区目前的旅游系统空间结构处于放射模式阶段,通过旅游线路体系的完善和空间结构的重组与优化,西安旅游区可演变为较为理想的扩展模式。