地下步行空间公共安全设计研究

公共安全一直以来都是城市发展的基本要求,随着城市的发展,我国地下空间开发利用也迅速发展, 而地下步行空间逐渐占据了重要位置,其本身的安全问题也日益突出。面对复杂的地下空间安全问题,笔者以地下步行空间的安全设计为基础,提出“安全地下步行空间设计”概念,并尝试从心理、行为、防卫、防灾安全四个方面分别进行相应的设计策略,对地下步行空间提出切实可行的措施,可为构建安全的地下空间建设提供借鉴。     

ISOLAN facility and its research program

The status of the IMP (Institute of Modern Physics) mass separator facility on-line to the heavy ion accelerator HIRFL in Lanzhou is described. The results for off-line and on-line tests as well as the research program are reported.     

A status report of the ISOL facility in Lanzhou

A new ISOL facility has been constructed for on-line use with the heavy-ion accelerator HIRFL in Lanzhou. The focal principle of ISOLDE-type separators is modified by including a quadrupole doublet lens in front of the magnet. The mass spectra of Ar and Xe isotopes were measured with a scanner inside the collection chamber in an off-line test. The resolving power is equal to 700–1200 by only using a single einzel lens.     

Inversion of the Li-Strahler canopy reflectance model for mappingforest structure

As part of a larger forest vegetation mapping process based on Landsat TM and digital terrain data, inversion of the Li-Strahler model provides estimates of tree size and cover for conifer stands. The vegetation maps are intended for use in natural resource management by the US Forest Service. Analysis of extensive field data in the form of “test” stands from four National Forests indicate the following about the Li-Strahler model: (1) the underlying assumptions of independence between tree size and crown shape are valid, (2) the means for tree geometry parameters vary between forest types, (3) estimates of forest cover are reliable, and (4) estimates of tree size are unreliable due to the breakdown in the relationship between image intra-stand variance and tree size. Improvements in estimates of tree size will require additional data beyond a single Landsat TM image, with multidirectional data a promising possibility     

The reconstruction of abnormal segments in HJ-1A/B NDVI time series using MODIS: a statistical method

HJ-1A/B is the first small satellite constellation built by China for environmental and disaster monitoring and forecasting. The satellite group has a 2-day repetition cycle and 30 m spatial resolution (charge coupled device camera). Thus, HJ-1A/B can provide hyper-temporal normalized difference vegetation index (NDVI) time series with a medium–high spatial resolution. However, the quality of the HJ NDVI time series can be abnormally low due to a number of factors, such as cloud cover, continuous fog, and haze. In the rainy season or in areas with serious atmospheric pollution, low-quality series often appear in succession, which is referred to as an abnormal segment. Neither the composition method nor quality flags satisfactorily solve this problem; therefore, a large amount of noise and long periods of abnormally low values often remain in HJ NDVI time series. This article presents a method to reconstruct the abnormal segments in HJ NDVI time series with the assistance of Moderate Resolution Imaging Spectroradiometer (MODIS) NDVI time series. The cointegration test was adopted to decide whether MODIS can be used for the reconstruction of NDVI time series for the corresponding HJ image pixels. Statistical quality control methods were used for singling out the abnormal segments in the HJ NDVI time series and establishing an error correction model that combines MODIS and HJ NDVI time series to perform the reconstruction. The study area is located in Jiangsu Province, China. Four-year (2009–2012) HJ multispectral images that cover the study area were used. The results show that abnormal segments in the HJ NDVI time series can be corrected using the proposed method. In a particular year, this method can decrease the root mean square error between the HJ NDVI time series and the reference sequence by 52.5%.     

W6平-1钻井液技术

W6平1是江苏油田钻井区域内难度较大的一口多绕障水平井,在进入A靶前要穿过一断层,处在破碎带里,技术难点为钻井液的携砂、破碎地层的防塌、钻井液的润滑等方面。采用BPS和MMH复配使用解决了携砂问题;用新型防塌剂和KLG以及封堵材料复配使用,对破碎地层进行了有效封堵;优选润滑剂,解决了水平井拖压防卡的问题。     

高密度薄膜树脂DGDX6095的开发及性能评价

采用UNIPOL气相流化床聚乙烯工艺技术,使用新型铬系催化剂、1-丁烯作为共聚单体,开发生产出高密度薄膜树脂DGDX6095,并采取多种分析测试方法对新开发的DGDX6095产品进行性能评价,结果表明,该产品性能与同类高密度薄膜产品DGDB6097、DGDA6098相当。     

海潮及滨海含水层地下水位变化的拟合与预测

海潮及受其影响的海岸带地下水位具有复杂的周期性变化和趋势性变化。该文建立趋势项与周期项之和的数学模型来描述水位的实际变化。用线性函数拟合其趋势项,用傅立叶级数拟合其周期项,用频谱分析和最小二乘法确定周期项函数。用实测水位和计算水位的误差平方和检验拟合结果。结果表明拟合效果好。所建立的数学模型可以用来对海潮和岸边地下水位变化进行预测,预测水位总体上能较好地反映实测水位的变化特点,适宜于较短时间的预测。