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191.
本文介绍了宇宙线空间物理学在我国的形成和主要研究内容,包括:(1)空间探测,有火箭探测、卫星探测;地面宇宙线台站观测;宇宙线的水下测量;(2)宇宙线空间物理学研究,有宇宙线的日地传输;宇宙线强度变化与CME事件;宇宙线的源物质与加速过程;宇宙线的地球物理效应.最后提到宇宙线与人体健康,特别是流行性感冒、大的太阳质子事件与地震现象、太阳宇宙线事件与天气和气候等的统计研究. 相似文献
192.
为了评价生物固沙材料在不同水分和养分供应条件下的应用效果,对沙漠苔藓结皮和含凹凸棒石固沙材料的叶绿素和生长进行了研究。结果表明:人工培养苔藓结皮与固沙材料的最佳配比为1∶1,由接种在沙面上的生物固沙材料的叶绿素a含量、强度和厚度决定。凹凸棒石显著提高了接种生物固沙材料的强度、叶绿素a含量和厚度。3种养分供应方式和3种模拟干旱区的间歇供水方式均能显著提高人工生物型结皮的厚度和强度。50%的养分处理是最佳的养分供应方式。接种生物固沙材料在隔天供水条件下具有较高的厚度和强度。较短的供水和养分供应间歇有利于沙漠生物结皮的生存和繁殖。 相似文献
193.
在日照市开展多目标区域地球化学调查,获取了表层土壤和深层土壤地球化学数据,通过对获得的地球化学参数进行统计分析,确定了日照市土壤地球化学基准值和背景值,认为日照市除部分元素或指标外,大部分元素或指标土壤地球化学基准值和背景值与全省土壤地球化学基准值和背景值接近。研究发现,日照市As,Cd,Cr,Cu,Hg,Ni,Pb,Zn等8种重金属元素背景值含量低于国家土壤环境质量标准的土壤一级标准限值,日照市土壤质量基本保持自然背景水平;而受工业化生产和城市化建设等后期人为活动影响,日照市表层土壤中Cd,C,Hg,N,P,S,Se,Corg等元素或指标出现明显富集,应引起重视。 相似文献
194.
Marine plastic debris has been a pervasive issue since the last century, and research on its sources and fates plays a vital role in the establishment of mitigation measures. However, data on the quantity of plastic waste that enters the sea on a certain timescale remain largely unavailable in China. Here, we established a model using material flow analysis method based on life cycle assessment to follow plastic product from primary plastic to plastic waste with statistical data and monitoring data from accurate sources. This model can be used to estimate and forecast the annual input of plastic waste into the sea from China until 2020. In 2011, 0.547 3–0.751 5 million tons of plastic waste entered the seas in China, with a growth rate of 4.55% per year until 2017. And the amount will decrease to0.257 1 to 0.353 1 million tons in 2020 under the influence of governmental management. The amount of plastic waste discharged from coastal areas calculated in this study was much larger than that from river, thus it is suggested to strengthen the governance and control of plastic waste in coastal fishery activities in China in order to reduce the amount of marine plastic waste input. 相似文献
195.
新疆小热泉子铜(锌)矿床同位素研究 总被引:12,自引:0,他引:12
小热泉子矿床是我国最近发现的一个中型富铜( 锌) 矿床,其矿床成因为众多的矿床学家所关注。本文对该矿床中不同类型矿石、矿物的S、O、H、Si 及稀有( 惰性) 气体He、Ar 同位素特征作了较祥细的论述,同时用KAr 法对硫化物的年龄测定进行了初步尝试。该矿床硫化物的δ34S 值为+ 1-5 ‰~+ 11-1 ‰,平均为6-15 ‰(46) ;3 He/4 He( 初始) 值为5 ×10 - 8 ~2-17 ×10 - 6 ,平均为0-64 ×10 - 6(6) ,40 Ar/36Ar 值为305-27 相似文献
196.
Riccardo Rodolfo‐Metalpa Chiara Lombardi Silvia Cocito Jason M. Hall‐Spencer Maria Cristina Gambi 《Marine Ecology》2010,31(3):447-456
There are serious concerns that ocean acidification will combine with the effects of global warming to cause major shifts in marine ecosystems, but there is a lack of field data on the combined ecological effects of these changes due to the difficulty of creating large‐scale, long‐term exposures to elevated CO2 and temperature. Here we report the first coastal transplant experiment designed to investigate the effects of naturally acidified seawater on the rates of net calcification and dissolution of the branched calcitic bryozoan Myriapora truncata (Pallas, 1766). Colonies were transplanted to normal (pH 8.1), high (mean pH 7.66, minimum value 7.33) and extremely high CO2 conditions (mean pH 7.43, minimum value 6.83) at gas vents off Ischia Island (Tyrrhenian Sea, Italy). The net calcification rates of live colonies and the dissolution rates of dead colonies were estimated by weighing after 45 days (May–June 2008) and after 128 days (July–October) to examine the hypothesis that high CO2 levels affect bryozoan growth and survival differently during moderate and warm water conditions. In the first observation period, seawater temperatures ranged from 19 to 24 °C; dead M. truncata colonies dissolved at high CO2 levels (pH 7.66), whereas live specimens maintained the same net calcification rate as those growing at normal pH. In extremely high CO2 conditions (mean pH 7.43), the live bryozoans calcified significantly less than those at normal pH. Therefore, established colonies of M. truncata seem well able to withstand the levels of ocean acidification predicted in the next 200 years, possibly because the soft tissues protect the skeleton from an external decrease in pH. However, during the second period of observation a prolonged period of high seawater temperatures (25–28 °C) halted calcification both in controls and at high CO2, and all transplants died when high temperatures were combined with extremely high CO2 levels. Clearly, attempts to predict the future response of organisms to ocean acidification need to consider the effects of concurrent changes such as the Mediterranean trend for increased summer temperatures in surface waters. Although M. truncata was resilient to short‐term exposure to high levels of ocean acidification at normal temperatures, our field transplants showed that its ability to calcify at higher temperatures was compromised, adding it to the growing list of species now potentially threatened by global warming. 相似文献
197.
198.
This paper derives the force of the electromagnetic radiation on left-handed materials (LHMs) by a direct application of the Lorentz law of classical electrodynamics. The expressions of radiation force are given for TE-polarised and TM-polarised fields. The numerical results demonstrate that electromagnetic waves exert an inverse lateral radiation force on each edge of the beams, that is, the lateral pressure is expansive for TE-polarised beams and compressive for TM-polarised beams. The investigation of the radiation force will provide insights into the fundamental properties of LHMs and will provide to better understanding of the interaction of light with LHMs. 相似文献
199.
大陆解体与被动陆缘的演化 总被引:4,自引:1,他引:3
火山型被动陆缘是大陆解体过程中形成的一类陆缘类型,其演化过程与活动陆缘一样复杂多变。随着近年来对大陆解体过程与被动陆缘演化的深入研究,对其沉积过程、岩浆活动以及变质作用研究都有了很大的进展。陆壳减薄解体的过程有许多不同的模式,不对称的简单剪切模式可能是火山型被动陆缘的成因,其机制是软流圈隆起的最大位置从剖面上看与地壳减薄最大位置不在一条垂线上,造成软流圈上升的岩浆在解体的大陆一侧形成火山型被动陆缘。被动陆缘的沉积建造由两套沉积物组成,一套是大陆解体的裂谷阶段所形成的陆相沉积物和双模式火山岩组合,另一套是稳定陆缘的复理石组合;岩浆作用中基性岩类反应了物质直接源于上地幔的主要特点,并有部分受到地壳混染的特征;变质作用中高温低压环境主要发生在裂谷作用阶段,其特点反映了大陆解体过程中随着时间的增温和减压过程,而拆离伸展阶段则被脆性变形所代替。 相似文献
200.