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391.
乳山湾外低氧海域沉积物中有机碳、氮、磷及其形态特征分析 总被引:3,自引:0,他引:3
根据2009年8月在乳山湾及其毗邻海域的综合调查,分析了该海域表层沉积物中有机碳、氮、磷含量及其组成形态的变化,初步探讨了影响底质理化参数变化的原因及对乳山湾外近岸底层低氧形成的影响.结果表明,乳山湾外近海为粉砂质岸滩,以细颗粒为主;底质中有机碳含量介于0.49% ~0.93%,平均值为0.69%;总氮含量介于382~1020 mg/kg,平均值为671 mg/kg;可溶性总氮含量介于23.0 ~ 60.0 mg/kg,平均值为44.0mg/kg,其中可溶性有机氮和氨氮分别占可溶性总氮的58.8%和38.8%;总磷含量介于138~769 mg/kg,平均值为356 mg/kg,有机磷是占有绝对优势的磷形态(62.5%).研究区域沉积物中总氮和湾内相当,有机碳、总磷含量普遍低于乳山湾内,但均明显高于南黄海区域,且呈还原性状态.调查区域内沉积物中相对较高的有机碳、氮、磷可能是在潮流作用下乳山湾与外海的物质交换所致,其耗氧过程是导致底层溶解氧亏损的重要原因,值得进一步关注. 相似文献
392.
新疆主要城市不同生态功能区夏季空气负离子特征 总被引:2,自引:0,他引:2
在不同天气状况下,对新疆8个主要城市5种生态功能区(林地、水体、景区、商业区和生活区)空气负离子浓度监测。结果表明:(1)不同生态功能区间空气负离子浓度差异显著(F=51.960,P= 0.000<0.001),顺序为林地(431个/cm3)>景区(398个/cm3)=水体(398 个/cm3)>生活区(313个/cm3)>商业区(270 个/cm3);(2)各功能区空气负离子浓度日变化均表现为清晨和傍晚高于午间。单因素方差分析表明林地、水体和景区午间空气负离子浓度与清晨和傍晚的差异不显著,生活区和商业区差异显著;(3)景区和林地[WTBX]CI[WTBZ]值(0.50和0.49)处于中等清洁范围,属C级;水体和生活区[WTBX]CI[WTBZ]值(0.45和0.29)处于容许范围,属D级;商业区CI值(0.24)在临界值以下,属E级;(4)从林地、水体、景区、生活区到商业区,D级和E级天气所占比例不断增加,B级和C级天气不断减少,说明空气质量逐步下降;(5)不同天气状况下各功能区空气负离子均表现为雨天>晴天>阴天>沙尘(浮尘)。 相似文献
393.
O. Dor C. Yildirim T. K. Rockwell Y. Ben-Zion O. Emre M. Sisk T. Y. Duman 《Geophysical Journal International》2008,173(2):483-504
394.
广州开发区的发展演变与空间效应研究 总被引:1,自引:0,他引:1
以广州开发区为研究对象,依据产业规模、发展速度和空间拓展等方面的因素,认为经过20多年的发展,其经历了起步发展、快速扩张、综合优化3个阶段的演变过程。开发区在自身经济实力增强和空间规模壮大的同时,产生了巨大的空间效应,使广州城市空间拓展方式从“连片式”向“跳跃式”转变,引导城市不断向东拓展;形成经济增长极,提升东部板块,改变了广州的地域空间结构,形成了新的功能格局。 相似文献
395.
396.
V.T.Trofimov 《地学前缘》2005,12(4):607-613
在地球各大陆上工程地质条件水平和垂直上的变化反映出它们的区域性,它受控于该地区的热量、湿度及其比率。这就是在类似地质结构的地区中,不同的纬度和海拔高度形成了不同的工程地质条件的原因。引入工程地质区这个概念的目的在于说明工程地质条件的区域性。工程地质区一词的意义是指一个大的工程地质地区或省,在其中主要由水的形态决定的岩土状态是均一的并从工程地质观点来看具有区域稳定性。已经确定了以下工程地质区类型:永久性的多年冻土区域、多年冻土和融化沉积共存区域,以及融化和不冻岩石区域,它们再细分为亚区。工程地质条件区域性概念要考虑的主要问题有:分区原则、工程地质区域的类型和种类、地球各大陆上工程地质区域的空间分布规律性、“理想”大陆上的分布模型。 相似文献
397.
Regional extension which initiates and promotes the rise of salt diapirs can also make diapirs fall once the supply of salt from its source is restricted. New observations on the 3D seismic data from a salt diapir in the Sørvestsnaget Basin suggest that salt moves until the end of the Eocene and is subtle to minor readjustments afterwards, revealing a more complex kinematics that previously described. Observations such as salt horns and sags and an antithetic fault linked to the western flank of the diapir suggest that salt syn-kinematics during Middle-Late Eocene included passive rising of the salt, followed by a fall. The salt horns are remnants of a taller salt diapir that, together with the indentation of the Middle-Late Eocene syn-kinematic sediment overburden above the salt, indicate diapiric fall due to restriction of salt supply by extension. Post-kinematic readjustments did not include diapiric reactivation by tectonic compression as previously thought, but minor salt rise by shortening due to gravity gliding after the tilting of the margin during Plio-Pleistocene glacial sediment loading and differential compaction of surrounding sediments. The salt diapir appears to be presently inactive and salt supply may have been restricted from its source already since Late Eocene. 相似文献
398.
Wael R. Abdellah Haitham M. Ahmed Mohammed A. Hefni 《Geomechanics and Geoengineering》2019,14(1):41-51
Stope stability is a key factor for the success of a mining operation. To optimise ore productivity while maintaining stope stability, the mining block/stope must be extracted in stages. Ore dilution will occur if the stope is not properly excavated/blasted. This study examines stope stability during mining in three stages, where the height of each stage stope is 10 m. The paper also presents simulation analysis of a typical steeply dipping tabular orebody at 1200 m depth below the surface, which is common in many Canadian underground hard rock mines. Numerical modelling analysis was conducted using the finite element program, RS2D, where the non-linear elasto-plastic Mohr-Coulomb failure criterion was adopted. The rock reinforcement system (i.e. cable bolts) was modelled/installed in the stope footwall after each mining stage to strengthen access drifts and stabilise the rock mass around the stope that was disturbed by mining activity. Results are discussed in terms of depth of failure zones, total deformation and axial forces in cable bolts with respect to mining stage. 相似文献
399.
贵州西南部贞丰背斜金(锑)成矿分析与预测 总被引:2,自引:0,他引:2
本文以近期贞丰背斜构造带金(锑)矿勘查成果,结合区域地质特征与规律,对贞丰背斜构造带成矿地质环境和控矿地质条件进一步作出全面分析,指出了有利金(锑)矿赋存地段,提出找矿远景区,对后续地质矿产勘查具有较强的指导意义。 相似文献
400.
Crack Coalescence in Molded Gypsum and Carrara Marble: Part 2—Microscopic Observations and Interpretation 总被引:9,自引:3,他引:6
Experimental uniaxial compression loading tests were conducted on molded gypsum and Carrara marble prismatic specimens to
study the cracking and coalescence processes between pre-existing artificial flaws. The study showed that material had an
influence on the cracking and coalescence processes (see the companion paper in this issue). As reported in the companion
paper, one of the pronounced features as observed in the high-speed video recordings was the development of macroscopic white
patches prior to the development of observable cracks in marble, but not in gypsum. This paper (part 2) deals with the microscopic aspects of the study. Specifically, the scanning electron microscope (SEM) and the environmental scanning electron microscope
(ESEM) imaging techniques were used to study the microscopic development of white patches and their evolution into macroscopic
tensile cracks and shear cracks in marble, and the microscopic initiation of hair-line tensile cracks and their evolution
into macroscopic tensile cracks in gypsum. The microscopic imaging study in marble showed that the white patches were associated
with extensive microcracking zones (process zones), while the extent of process zone development in gypsum was limited. The
comparison of the macroscopic and microscopic results indicates that the different extent of microcracking zone development,
related to the material textural properties, is a key factor leading to different macroscopic cracking behavior in gypsum
and marble.
相似文献
H. H. EinsteinEmail: |