高层隔震结构扭转分析

为研究高层隔震结构在地震作用下的扭转效应,用Etabs软件建立1个高层抗震结构和4个具有不同扭转特性的高层隔震结构的空间模型进行地震响应分析,以验证此原则上部结构质量中心与隔震层刚度中心的重合与否对结构扭转效应的影响程度,而后考察偏心高层隔震结构在偶然偏心地震作用下结构的扭转效应。结果表明:由于地震作用的减小,扭转效应要远小于原抗震结构,且隔震本身对于结构扭转效应的抑制效果要好于上述原则;扭转效应的减震率大于平动效应的减震率。布置在隔震层平面外围的铅芯橡胶隔震支座对隔震层的扭转有一定的控制作用。     

Temporal and spatial variability of dissolved organic carbon concentration in the Xijiang River, South China

A whole year analysis of riverine dissolved organic carbon (DOC) concentrations in the Xijiang River (XJR), South China, showed that the mean riverine DOC concentration (1.24 mg L-1) in the XJR was notably lower than the averaged value (5.75 mg L-1) of the global riverine DOC concentration in several major rivers. There is an inconspicuous monthly fluctuation of the DOC signal in the XJR, but on a semi-yearly time scale, however, the riverine DOC concentration had significant difference between hydrological...     

EH4方法在辽宁本溪大台沟铁矿勘查中的应用

EH4连续电导率剖面测量是近年来地质勘察中采用的新方法,可以推断隐伏铁矿体的埋深、宽度、规模及产状。本溪大台沟铁矿勘查中进行了EH4连续电导率剖面测量,经钻探验证。取得了较好的效果。寻找深部隐伏铁矿体,磁法测量和EH4测量2种方法综合运用,为后续钻探工作提供更充分的依据。     

Mineralogy,major and trace element geochemistry of riverbed sediments in the headwaters of the Yangtze,Tongtian River and Jinsha River

We collected riverbed sediments of the headwaters of the Yangtze River (Chumaer River, Tuotuo River, Gaerqu River and Buqu River), Tongtian River and Jinsha River (HTJR) flowing on the eastern Tibetan Plateau and analyzed their mineralogical features, major and trace element contents. The results show: (i) very poor correlations of Na₂O, K₂O, CaO, Ba, and Sr to SiO₂, LREE to Th, HREE to Hf, and Ta/La to Ti, and characteristics of Eu anomaly (the ratios of (Eu/Eu^*)_N range from 0.60 to 0.83 with an average value of 0.71) all indicate that the Jinsha River sediments have not undergone much mineralogical sorting; (ii) illite and chlorite are predominant clay minerals, and quartz, calcite, dolomite, albite, and K-feldspar are prevailing non-clay minerals. The characteristics of mineral assemblage indicate relatively weak chemical weathering degree in these river basins; (iii) very high contents of Fe₂O₃, MgO, TiO₂, Sc, V, Cr, Co, and Ni at Panzhihua mainly result from the huge-sized V–Ti magnetite deposits occurred in layered gabbroic intrusion; and (iv) the chemical alteration index (CIA) in the HTJR ranges from 46.5 to 69.2 and with an average value of 60.5 which indicates relatively weak weathering degree.     

基于灰色系统理论的河南旅游业发展研究

优越的地理位置和丰富的旅游资源使得河南的旅游业快速发展,对旅游业发展进行预测可以为旅游业发展决策提供帮助。运用灰色系统理论的灰色关联度分析法,对河南省旅游业的影响因子进行定量分析,得知影响河南旅游业发展的三大因素是国内生产总值、人均国内生产总值和民用汽车数量。建立河南国内旅游接待人数和国内旅游收入的灰色GM(1,1)预测模型。结果表明,未来5年河南省旅游业发展势头强劲。     

Numerical Investigation of the Dynamic Mechanical State of a Coal Pillar During Longwall Mining Panel Extraction

This study presents a numerical investigation on the dynamic mechanical state of a coal pillar and the assessment of the coal bump risk during extraction using the longwall mining method. The present research indicates that there is an intact core, even when the peak pillar strength has been exceeded under uniaxial compression. This central portion of the coal pillar plays a significant role in its loading capacity. In this study, the intact core of the coal pillar is defined as an elastic core. Based on the geological conditions of a typical longwall panel from the Tangshan coal mine in the City of Tangshan, China, a numerical fast Lagrangian analysis of continua in three dimensions (FLAC^3D) model was created to understand the relationship between the volume of the elastic core in a coal pillar and the vertical stress, which is considered to be an important precursor to the development of a coal bump. The numerical results suggest that, the wider the coal pillar, the greater the volume of the elastic core. Therefore, a coal pillar with large width may form a large elastic core as the panel is mined, and the vertical stress is expected to be greater in magnitude. Because of the high stresses and the associated stored elastic energy, the risk of coal bumps in a coal pillar with large width is greater than for a coal pillar with small width. The results of the model also predict that the peak abutment stress occurs near the intersection between the mining face and the roadways at a distance of 7.5 m from the mining face. It is revealed that the bump-prone zones around the longwall panel are within 7–10 m ahead of the mining face and near the edge of the roadway during panel extraction.     

河南鹤壁地区太原组有孔虫动物群及石炭-二叠系界限的探讨

通过对华北地台河南鹤壁地区太原组有孔虫动物群的系统研究,共鉴定出有孔虫化石18属33种,建立了一个区域性有孔虫动物组合带：Bradyina—Palaeotextularia组合带,根据有孔虫化石的属种类型、数量,应用数理统计方法得出组合带有孔虫化石在地层中的比例变化情况,并根据化石组合带与国内其它地区的有孔虫动物群进行对比研究,认为鹤壁剖面有孔虫动物群Bradyina—Palaeotextularia组合带归于晚石炭世晚期的早期（C2^2-）,进而对研究区石炭-二叠系界线的划分进行探讨,界限应该放在第16层（泥岩）和第15层（灰岩）之间。     

������ģ������С���������ڶ�Դ���������ں��е�Ӧ��

????????С????????????????????ж???????????????????????????????????????????????????????????????????顣?????????????????С??????????????????????3.6??10????^-5??ms????^-2??????????????С???????????????????????????????????????????????????4.6??10????^-5??ms????^-2??????????????????????????????????????С?????????????????????????????п???????Ч?????     

Thickness distribution and extent of sea ice and snow in Prydz Bay and surrounding waters observed in 2012/2013 austral summer

Three ship-based observational campaigns were conducted to survey sea ice and snow in Prydz Bay and the surrounding waters(64.40°S–69.40°S, 76.11°E–81.29°E) from 28 November 2012 to 3 February 2013. In this paper, we present the sea ice extent and its variation, and the ice and snow thickness distributions and their variations with time in the observed zone. In the pack ice zone, the southern edge of the pack ice changed little, whereas the northern edge retreated significantly during the two earlier observation periods. Compared with the pack ice, the fast ice exhibited a significantly slower variation in extent with its northernmost edge retreating southwards by 6.7 km at a rate of 0.37 km?d-1. Generally, ice showed an increment in thickness with increasing latitude from the end of November to the middle of December. Ice and snow thickness followed an approximate normal distribution during the two earlier observations(79.7±28.9 cm, 79.1±19.1 cm for ice thickness, and 11.6±6.1 cm, 9.6±3.4 cm for snow thickness, respectively), and the distribution tended to be more concentrated in mid-December than in late November. The expected value of ice thickness decreased by 0.6 cm, whereas that of snow thickness decreased by 2 cm from 28 November to 18 December 2012. Ice thickness distribution showed no obvious regularity between 31 January and 3 February, 2013.     

未来气候变化对云南柠檬气候适宜性的影响

气候变化影响柠檬生长、产量和品质,本文利用云南省125个国家气象站1981—2018年,月平均气温、月平均降水量、月日照时数,进行基准年代下云南柠檬气候适宜性分区;采用RCP2.6、RCP4.5、RCP8.5气候情景模式,研究2021—2030年、2031—2040年、2041—2050年云南柠檬气候适宜区的变化,探讨未来气候变化背景下,云南柠檬气候适宜性变化,以期对柠檬产业布局、规划、引种提供科学的指导。结果表明:21世纪中叶,RCP2.6情景下柠檬最适宜种植区增加了3成左右,RCP4.5情景下柠檬最适宜种植区增加了5成左右,RCP8.5情景下柠檬最适宜种植区增加了9成左右。但由于受降水因子的限制,中度适宜区到2041—2050年开始缩减,总的可适宜种植区(高度适宜区+中度适宜区)基本趋于稳定,这将给柠檬在云南的种植发展提供广阔空间。