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101.
许康生 《地震地磁观测与研究》1992,13(2):15-19
地震泼由多种频率成份组成,在其传播过程中。由于地球介质的滤波作用,随着传播距离的增大。高频成份逐渐被衰减。周期越大的成份传播越远。因此,在地震观测上,不同频带的地震仪用于观测不同震中距范围的地震,使仪器较好地响应,就我国台网而言,短周期仪用于地方震、近震的监测,中长周期仪和长周期仪用于远震,极远震的监测,其中长周期仪偏重于记录极远震。但作者在实际分析工作中注意到,短周期仪的记录应用于远震,极远震的分析,显示出独特的作用,充分挖掘和利用短仪资料,将会更加丰富远震、极远震的震相资料。本文以高台地震台的资料为依据,从震中距和震级角度,与中长仪和长仪作比较,对短仪记录远震、极远震的震相及特征作了统计分析与初步探讨,并对新疆地区“影区”地震S波的记录、日本地区地震_PPcP等震相的出现提出了现象的存在,给出了相应的观测结果,以待步一步研究。 相似文献
102.
新地球观 总被引:11,自引:0,他引:11
One of the most important achivements on science in 20th century is the new recognition on the Earth:the Earth,out of the other planets, exhibits very peculiar features because it has an extremely complex and active periphery part (surfacial layers). This periphery part is an open system sustained by inputting solar energe , which is captured , transfered and stored by life. Through the system , cyclings of matters and energe flow are driven and regulated by life activities. This system is self-equilibrated,self-controlled and far away from astrophysical and thermodynamic equilibria mainly because of life and life activities.
Development of human calture influences increasingly on流Earth's periphery system , at last , the natural biosphere that has existed for 3 billion years on the Earth's surface will inavoidably be replaced by so called "noosphere",which is man一reconstructed,man-controlled and unstable system. Thus the fate of the Earth,to a great extent,will be determined by the direction of human calture evolution.
相似文献
Development of human calture influences increasingly on流Earth's periphery system , at last , the natural biosphere that has existed for 3 billion years on the Earth's surface will inavoidably be replaced by so called "noosphere",which is man一reconstructed,man-controlled and unstable system. Thus the fate of the Earth,to a great extent,will be determined by the direction of human calture evolution.
相似文献
103.
104.
采用SPSS软件,对2003年01月至2004年12月期间,倒天河水库和利民水库逐月水质监测数据进行数理统计分析,结果表明毕节市饮用水水质污染有较明显的季节变化和空间差异;且不同污染物对水体污染的贡献率各不相同,总磷和粪大肠菌群所占份额最大,方差累积贡献率达77%。在此基础上,利用加权综合污染指数对水体水质污染现状进行综合评价,结果显示倒天河水库和利民水库,水质污染总体较轻.饮用水水质符合《地表水环境质量标准(GB3838—2002)》中Ⅲ类水质标准;最后提出加大水环境保护的建议。 相似文献
105.
Seng Chee Poh Norhaxati Mohd Tahir Hafiza Mohamed Zuki Mohd Izwadi Musa Khai Hock Ng Noor Azhar Mohamed Shazili 《中国地球化学学报》2006,25(B08):56-56
A total of 63 soil samples from 3 different soil profiles (urban, suburban and industrial areas) in major towns in the east coast of Peninsular Malaysia were analyzed for the total concentrations of Cu, Zn, Pb, Ni and Cr. The soil samples were subjected to acid digestion and the concentrations of total metals extracted were measured or flame atomic absorption spectrometry and inductively coupled plasma - atomic emission spectrometry. According to the result of this study, Pb and Zn concentrations in urban soils are much higher than those of industrial and suburban soils. Total concentrations of Cu and Cr in industrial soil samples are high compared to other two soil profiles and Ni concentrations in the suburban area are slightly higher those of urban and industrial soils. Since Malaysia has not yet to come up with her own soil maximum allowable limit, the heavy metal concentrations were compared with the Dutch maximum allowable limit. The results indicated that the median of heavy metals values in the three different soil profiles is still below the Dutch system limit. From the maximum allowable value obtained from the Dutch system, a contamination/pollution (C/p) index for each site was calculated for the set of these five heavy metals. An advantage of using this method is to make a differentiation between pollution (C/p〉1) and contamination (C/p〈1) status in soils as well as being able to characterize each status into 5 different categories (slight, moderate, severe, very severe and excessive). 相似文献
106.
Min SU Min LIU Dongping TIAN Guohong ZHANG Liangli HONG Yuxia GAO 《中国地球化学学报》2006,25(B08):61-61
Background & aim: To investigate and analyze the elements pollution in the extremely high tumor risks residents in the Chaoshan littoral, southern China. Methods: 19 elements including Cr, Mn, Ni, Sr, Pb, Zn, Co, Sn, Th, Tl, Se, Hg, Cu, Mo, Cd, Sb, U, Ge, As, and Al were measured from 145 hair samples of residents from the high-risk Nanao Island (mortality of cancer 173-156/106 in recent 30 years), Shantou high-risk village (mortality of cancer 230.4/106 in recent three years), and two controls Shanwei (mortality of cancer 32/106 in 1970s) and Meizhou Hakka (incidence of cancer 103/106 ) using AAS, AFS, ICP-MS methods collaborated with Beijing University. And 21 samples of water, 18 samples office from the Nanao Island, Shantou high-risk village, and other low-risk controls were measured using the same methods. Results: The element analysis showed that levels of CD, PB in the Shantou high-risk village were the highest, Hg, MN, SR, SB, TH, U on the Nanao Island were the highest in hairs. Conclusions: It is indicated that there occurred elements pollution among the local high-risk population. 相似文献
107.
108.
109.
Wei ZHANG Congqiang LIU Zhiqi ZHAO 《中国地球化学学报》2006,25(B08):172-172
Boron has two stable isotopes (^10B and ^11B) with relative abundances of about 20% and 80%, respectively. Boron isotopic ratios in natural materials show a huge range of variations, from -70‰ to +60‰, when expressed with the classical δ^11B notation. Most of these isotopic variations occur at the surface of the Earth. Hence, boron isotopic composition can be used as a sensitive tracer in geochemical study, for instance, to identify the different sources of contamination and factors controlling the salinity of groundwater. During the last decade, boron isotopes have been used to discriminate between the influences of seawater intrusion and anthropogenic discharge. But few of those researches can precisely identify the different sources of contamination. We measured the boron concentrations and boron isotopic ratios of groundwater samples collected in Guiyang City, as well as the major ions. The results indicate that the major ion composition of the groundwater in the investigated area is mainly controlled by the interactions between water and the dominant rock i.e. carbonates. All the water compositions are characterized by high concentrations of Ca^2+, Mg^2+, HCO3^-, SO4^2-, and NO3^-, which are the dominant contaminants. Both dissolved boron concentrations and isotopic ratios show large variations among the ground waters, from 2 μg/L to 90 μg/L and from -6‰ to +26‰, respectively. The boron concentrations and isotopic ratios indicate that the river across the studied city has been seriously contaminated by urban discharge. Boron concentrations of fiver water samples varied from 20 μg/L to 140 μg/L, with an average δ^11B value of +2.0‰. Using boron isotopic compositions and different geochemical indices allowed us to clearly identify and distinguish the two major sources of contamination, agricultural activity and urban wastewater. Both of the two sources are characterized by high boron concentrations but their boron isotopic compositions significantly differ. 相似文献
110.
Rajasekhar Balasubramanian Chanbasha Basheer Kang Lisa Siao Wei See 《中国地球化学学报》2006,25(B08):183-183
Microorganic pollutants such as polycylic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and total petroleum hydrocarbons (TPHs) are known to be present in urban ambient air. These organic compounds are prone to atmospheric transport and deposition over long distances, thus enabling them to accumulate even in regions remote from their sources. Deposition from the atmosphere can be via direct deposition and exchange with crops that may be directly or indirectly ingested by humans. It can also take place via wet and dry deposition and air-water exchange. Following their deposition, these microorganic pollutants tend to accumulate in soils, sediments and in human and ecological food chains. There are many reports in the literature on the atmospheric concentrations of microorganic pollutants, but there are few reports and data in Asia. This study was performed in Singapore to determine the relative amounts of persistent organic pollutants and TPHs in ambient aerosols. One of the important sources of these organic compounds in Southeast Asia is thought to be biomass burning (vegetation fires). Hence, air sampling was conducted during both smoke haze and non-haze periods. The data obtained from this study will be presented and discussed. 相似文献