麻雀岗隧洞——典型硝土地层掘进技术

通过对麻雀岗隧洞掘进技术的探索与总结，为典型硝土层隧洞设计和掘进施工提供了一些可借鉴的施工方法。     

1990—2010年黄河宁蒙段所处流域土地利用变化

以Landsat TM和ETM+遥感影像为基础数据源,应用地理信息系统技术,对黄河宁蒙段所处流域1990-2010年土地利用变化进行了监测,并结合气候变化、人类活动和政策因素探讨了土地利用变化的驱动力,初步分析了土地利用/覆被变化对流域水-沙关系的影响。结果表明：（1）20年来研究区建设用地面积增加了1 310.04 km²,耕地面积增加了611.15 km²,水域和草地面积分别减少了1 499.51 km²和474.93 km²;（2）20年来黄河宁蒙段所处流域土地利用变化速度经历了缓慢变化-显著变化-急剧变化的过程。各土地利用类型在后10 年（2000-2010年）的变化速度均比前10年（1990-2000年）大;（3）研究时段内草地和未利用地转化为林地,草地和耕地被开发为建设用地,未利用地和草地被开垦为耕地;（4）人类活动和政策因素是影响20年来土地利用变化的主要驱动因子,但人口数量的增加、经济的发展及环境政策的调整对研究区土地利用变化的影响更为显著;（5）1990-2010年流域耕地和林地面积分别增加了611.15 km²和543.19 km²,植被覆盖度由1990年的34.7%增加到2010年的40.8%。林地和耕地面积的增加均使得流域总蒸发量增加,灌溉用水增加,从而径流量减少,植被覆盖度的增加使得流域径流量和输沙量均降低。     

古镇文化身份脆弱性的社会建构及其意义——多元话语分析模式的尝试

在建构主义研究范式的指导下选择多元话语分析方法,以江南水乡古镇周庄为案例地,对古镇文化身份的脆弱性进行社会建构分析。结果表明不同阶段政府旅游发展政策的改变、开发商的本质、传媒与专家系统的推力、游客凝视及对文化的态度、外来人群及其影响下原住居民的交往方式和价值取向共同建构了古镇文化身份脆弱性的形成过程。最后提出改造物质与生活环境、营建文化共同体、提倡理性交往等古镇文化身份脆弱性的治理对策,以期为文化遗产保护与可持续发展政策制定提供参考。     

Toward Equal Opportunity of Primary Education: Introducing a Lottery into China’s Proximity-Based Enrollment System

A serious spatial inequality of educational opportunity in school enrollment persists worldwide. The use of random mechanisms in school allocation might improve spatial equality, with lotteries applied in some choice-based systems. China uses a proximity-based assignment, yet the optimization of spatial equality of educational opportunity by introducing a lottery has received little consideration. To achieve the maximum spatial equality of educational opportunity, in this study, a random proximity-based model was developed, and the swarm optimization method was used to solve the model. A case study in the Shijingshan district of Beijing was used to illustrate the model outputs. For comparison, a proximity-based model was also developed and solved. After introducing a lottery into a proximity-based enrollment system, the spatial disparity of educational opportunity was reduced by 70 percent. The average travel distance to school increased 3.5-fold but was still much less than the actual average distance of 4.3?km. Relaxing the maximum travel distance constraint could significantly improve spatial inequality. Although total equality was significantly improved, only 51 percent of students benefited from increased opportunities, which implies that the model could be adopted in a centralized institutional context, such as China, but might be ineffective in a democratic system.     

An explicit method for numerical simulation of wave equations

In this paper, a method to develop a hierarchy of explicit recursion formulas for numerical simulation in an irregular grid for scalar wave equations is presented and its accuracy is illustrated via 2-D and 1-D models. Approaches to develop the stable formulas which are of 2M-order accuracy in both time and space with M being a positive integer for regular grids are discussed and illustrated by constructing the second order (M = 1) and the fourth order (M = 2) recursion formulas.     

逆插支流的演变与河流掉向的关系

逆插支流是相对正插和顺插支流而言,它们之间的演变过程,受到新构造运动、流水地质作用等诸因素的影响。尤其是逆插支流的演变,对主干河流是否掉向,意义重大,但不是所有逆插支流都对指示主干河流掉向有意义。试图从演变的角度,来剖析逆插、正插和顺插支流的内在联系,以求探讨上述问题。     

Data weighting and solution assessment in combination

A data weighting method for combining different geodetic data based on statistical tests of the residuals is discussed. By requiring the residuals of combination solution to be white Gaussian as a sample of random noise, the relative weight factors can be determined internally, independent of external comparisons. To achieve this goal and to assess the solution, the Pearson χ² and higher-order moments of residuals are used to measure quantitatively the discrepancies between the residuals and white Gaussian noise. Received: 30 June 1998 / Accepted: 19 April 1999     

石化企业工业设备震害经验分析

在国内外的大地震中，石油化工企业的震害经验是比较少的，过去的记载只是笼统地描述各类设备和构筑物的地震损坏情况，而与地震烈度相联系的定量说明却很少，看不出在各种地震烈度作用下震害的规律，因此整理并归纳内外七，八度地震烈度作用下石油化工设备和构筑物的震害情况，给出与地震烈度相联系的定量说明，使震害预测更有科学的依据。     

Toxicity of Ionic Liquids

The dramatic growth in ionic liquid research over the past decade has resulted in the development of a huge number of novel ionic liquids, as well as many associated applications. The perceived environmentally friendly nature of ionic liquids, which results from their negligible vapor pressure, is now under scrutiny since although they will not evaporate into air, it is not possible to guarantee that they will never enter the environment. Toxicity research studies including ecotoxicity, have recently received broad attention and the commonly accepted notion that ionic liquids have low toxicity has been shown to be incorrect. This review attempts to highlight the progress of ionic liquid toxicity research, as well as the development of degradable and bio‐renewable ionic liquids.     

An equal area conversion model for rasterization of vector polygons

Vector-raster conversion is one of the classic research topics in the field of Geographical Information Systems (GIS). The algorithms commonly used in GIS are devoted to maintaining the vector polygons’ shape characteristics, but neglect the gain and loss of a polygon’s area, which is another important attribute. This paper proposes an equal-area conversion model based on an area compensation optimization principle. According to the topological relationship among polygons and boundary grids, a neighborhood compensation principle was adopted to assign the attributes of boundary grids and a global optimization algorithm was developed to minimize area distortion in the whole data set. Two experiments were designed and the results indicated that this algorithm not only guaranteed the area error is as small as possible, but also has the advantage as being adaptive to polygon shape and spatial structure.