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961.
In the present study, measurements of surface ozone (\(\hbox {O}_{3}\)) and its precursors (NO and \(\hbox {NO}_{2}\)) were carried out at a sub-urban site of Agra (\(27{^{\circ }}10'\hbox {N}\), \(78{^{\circ }}05'\hbox {E}\)), India during May 2012–May 2013. During the study period, average concentrations of \(\hbox {O}_{3}\), NO, and \(\hbox {NO}_{2}\) were \(39.6 \pm 25.3\), \(0.8 \pm 0.8\) and \(9.1 \pm 6.6 \, \hbox {ppb}\), respectively. \(\hbox {O}_{3}\) showed distinct seasonal variation in peak value of diurnal variation: summer \({>}\) post-monsoon \({>}\) winter \({>}\) monsoon. However, \(\hbox {NO}_{2}\) showed highest levels in winter and lowest in monsoon. The average positive rate of change of \(\hbox {O}_{3}\) (08:00–11:00 hr) was highest in April (16.3 ppb/hr) and lowest in August (1.1 ppb/hr), while average negative rate of change of \(\hbox {O}_{3}\) (17:00–19:00 hr) was highest in December (–13.2 ppb/hr) and lowest in July (–1.1 ppb/hr). An attempt was made to identify the \(\hbox {VOC--NO}_{\mathrm{x}}\) sensitivity of the site using \(\hbox {O}_{3}/\hbox {HNO}_{3}\) ratio as photochemical indicator. Most of the days this ratio was above the threshold value (12–16), which suggests \(\hbox {NO}_{\mathrm{x}}\) sensitivity of the site. The episodic event of ozone was characterized through meteorological parameters and precursors concentration. Fine particles (\(\hbox {PM}_{2.5}\)) cause loss of ozone through heterogeneous reactions on their surface and reduction in solar radiation. In the study, statistical analyses were used to estimate the amount of ozone loss.  相似文献   
962.
The adsorption behaviors of Cr(VI) on laterite from Guizhou Province were studied in this paper, and the adsorption mechanism was discussed as well. Results showed that different mineral compositions in the laterite would cause differences in the capacity of laterite to absorb Cr(VI). Gibbsite, iron oxide minerals and non-crystalloids are the main contributors to enhancing the capacity of laterite to absorb Cr(VI). The pH of the solution is an important factor affecting the adsorption of Cr(VI) on laterite. Acidic environment (pH=2–5) is favorable to the adsorption of Cr(VI). The amount of adsorbed Cr(VI) decreases with increasing pH of the solution. With increasing initial concentrations of Cr(VI), the amount of adsorbed Cr(VI) increases first, and then decreases. The optimal adsorption concentration of Cr(VI) on laterite is 250 μg/mL. The adsorption of Cr(VI) on laterite is a rapid process, about 80% Cr(VI) will be adsorbed within 2 hours. And the adsorption of Cr(VI) on kaolinite is a slow process.  相似文献   
963.
The near-infrared variable source, IRAS 04000+5052, was observed using the Italian 1.5 m TIRGO infrared telescope, located in the Gornergrat Observatory, Switzerland. High-resolution images were obtained in the JHK broad bands and H2 S(1) 1-0, Brγ narrow bands. Photometry and astrometry were also carried out. From the observations, it is found that IRAS source is not a single young object, but a small-sized, compact star-forming region with many young objects. Even in such a small and compact region, stars are not formed at the same time.  相似文献   
964.
本文在假设荷电球体内部物质密度为ρ_m=μγ~α,电荷密度为ρ_e=ρ_0γ~(b_e-λ/2)的情况下,严格求解Einstein-Maxwell场方程,求得了静态荷电球体的一个较为普遍的内部解。这个解可以看作是Wyman得到的内部解推广到荷电情况下的结果,并且将Wilson,李鉴增,Santos,Pant和Sah等人给出的许多结果作为自己的特例包括在内。  相似文献   
965.
Whole-rock compositions of muscovite-bearing amphibolite, trondhjemite, pegmatite and quartz-muscovite rocks from Sierra del Convento and La Corea mélanges (eastern Cuba), as well as mineralogy, record complex circulation of Ba-rich fluids and melts in the subduction environment. Partial melting of fluid-fluxed, MORB-derived amphibolite produced trondhjemite magmas that crystallized at depth, in some cases evolving into pegmatites. Qtz-Ms rocks probably crystallized from primary fluids derived from subducted sediments. All these rocks have elevated concentrations of large-ion lithophile elements, especially Ba (up to 11,810 ppm), presumably released from slab sediments by fluids and/or melts. Fluid–rock interaction produced crystallization of phengite in parental amphibolites. The phengite crystallized in all types of rocks is rich in Ba, with concentric zoning, characterized by Ba-rich cores and Ba-poor rims, indicating a compatible behaviour of Ba in the studied systems. Zoning in phengite is governed primarily by the celadonite (tschermak) exchange vector ((Mg,Fe)Si-(Al)-2), with more moderate contributions of the celsian (BaAl-(KSi)-1) and paragonite (NaK-1) exchange vectors. Late remobilization of Ba at relatively low temperature formed retrograde celsian. The compatible behaviour of Ba in the studied rocks strengthens the importance of the stability of phengite for the transfer of LIL elements from the subduction to the volcanic arc environments.  相似文献   
966.
The impact of increased temperature on the Third Pole, as the Himalayas is referred to, and the likely cascading impacts on the general downstream hydrology have been widely noted. However, the impact on fluvial geomorphology has not received specific attention. Change in the glacial domain in terms of melt increase will change discharge and sediment flux into fluvial system, which will induce changes in fluvial processes and forms. The present work attempts to study this process-based glacio-fluvial coupling in the two neighbouring glaciated river basins in the Northwest Himalaya, viz., the Sutlej and the Yamuna river basins till the mountain front. A total of 194 samples of river, tributary and groundwater of pre- and post-monsoon seasons in the two river basins were analysed for stable isotopes. The trend of δ18O and electrical conductivity along the mainstream gives qualitative idea on the influence of headwaters in the downstream of the catchment thereby allowing inference on melt contribution. Further, two component mixing model using stable oxygen isotope of two seasons water samples showed that melt contributes about 41.1–66.8 and 6.6–10.6% at different points to the total river discharge in the Sutlej and the Tons River (the glaciated, major tributary of the Yamuna River) basins, respectively. For different scenarios of increase in melt, stream power increase in the Sutlej River basin is significant as opposed to the Tons River. River channel in the Sutlej River basin will be significantly more impacted in comparison with the Yamuna River system.  相似文献   
967.
豫陕鄂交界区县域综合发展水平测度及障碍因子分析   总被引:1,自引:0,他引:1  
李许红  王永生  刘释疑 《地理科学》2022,42(10):1757-1766
以豫陕鄂交界区为研究对象,测度2000—2017年豫陕鄂交界区县域的综合发展水平,探析其空间分异特征、演化趋势和障碍因素。结果表明:① 2000—2017年,豫陕鄂交界区县域综合发展水平逐步提升,年均增速为6.08%,县域间发展的空间差异逐渐增大;② 县域综合发展水平在空间上呈正相关性,热点显著区呈现由东南部向西南部再向东南部迁移变化特征,冷点显著区在2005年前主要分布在安康市和商洛市,之后主要聚集在南阳市;③ 人文和经济要素为中度和中高障碍水平,资源和环境要素为极低和低障碍水平;随着时间的推移,障碍因子在不同县域空间阻力的分异特征更加显著。④ 豫陕鄂交界区县域发展空间阻力模式可划分为3种类型,其中人文资源要素制约型是主要的空间阻力模式。最后,基于不同空间阻力模式特征解析,提出了分区发展策略。  相似文献   
968.
岱崮地貌是一种寒武系碎屑岩之上的平顶灰岩地貌,为中国五大地貌之一,对其研究具有地质学、古地理环境等科学意义。本文通过野外地质调查及室内研究,分析研究了岱崮地貌的特征、成因和演化,得出以下结论:1) 岱崮镇的崮主体呈NW向展布,由崮体和崮基组成。崮体包括崮顶、崮腰和崮底,崮顶为灰岩,崮腰和崮底以碎屑岩为主,崮基为前寒武系岩浆岩或太古宇泰山群;2) 近水平岩层是岱崮地貌发育的基础;3) NNW向、NW向和近EW向断层是岱崮地貌形成的根本因素,NW向和NE 向节理是主控因素,控制了岱崮地貌的走向、密度;4) 岱崮地貌古生代以来经历了多个时期的演化,经过加里东运动、海西运动和印支运动留存的寒武系-中奥陶统、上石炭统-二叠系是岱崮地貌形成的基础,燕山期中侏罗世末-晚侏罗世(162~149.8 Ma)、白垩纪(140~90 Ma)及喜马拉雅早期(65~43 Ma)产生的断层及节理是岱崮地。  相似文献   
969.
公元1328~1330年寒冷事件的历史记录及其意义   总被引:1,自引:1,他引:1       下载免费PDF全文
元人刘岳申记载了公元1328、1329、1330年连续三年间,江西先后遭遇了大雪、江河结冰与夏季低温等百年罕见的寒冷气候。公元1328~1329年降雪的南界至少已达南岭;公元1329年冰冻的南界至少已达北纬27度左右的吉水县,而江西南部地区公元1330年夏季气温与我国北方坝上地区相当。此降温幅度已与17~19世纪明清小冰期中的极端寒冷年份相近,在过去2000年中亦属于并不多见的极端寒冷年份。  相似文献   
970.
This paper investigates the impact ash fall would have on dairy farming, based on a study of ‘Tulachard’, a dairy farming operation at Rerewhakaaitu, North Island, New Zealand. It includes analysis of the potential effects on the dairy shed and milking machine, electrical supply and distribution, water supply and distribution, tractors and other farm vehicles, farm buildings (haysheds, pump sheds, implement sheds, etc.), milk-tanker access to the farm and critical needs of dairy cows and farm to keep milking. One of the most vulnerable areas identified in the study was the cooling of milk at the milking shed, pending dairy tanker pick-up. The cooling system’s condenser is exposed to the atmosphere and falling ash would make it highly vulnerable. Laboratory testing with wet and dry ash was conducted to determine its resilience to ash ingestion. It was found to perform satisfactorily during dry testing, but during wet testing significant clogging/blocking of the condenser’s radiator occurred, dramatically reducing airflow through the condenser. Specific mitigation recommendations have been developed that include cleaning with compressed air and adapting farm management techniques to lessen usage of the condenser during an ash-fall event. Specific recommendations for management of dairy farm operation are given to mitigate the effects of an ash-fall event.
James W. ColeEmail:
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