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141.
内凸筋口琴管,是汽车空调的一种新型散热管.具有散热效果好、单位面积小、重.量轻等优点.此文介绍了连续挤压内凸筋口琴管模具的设计方法及其模具芯头的冷挤压加工. 相似文献
142.
143.
时间序列分析及Monte Carlo方法在降水预报中的应用 总被引:2,自引:0,他引:2
文章分别阐述了时间序列分析方法及Monte Carlo(蒙特卡洛)方法的基本原理和计算方法,并将其应用于降水预报的实例之中。时间序列分析是对降水资料进行观察、研究,用一定的数学方法建立预测模型,使时间序列向外延伸,从而获得序列的发展变化趋势,确定变量的预测值,精确的预报每一时段的降水量。蒙特卡洛方法是根据降水资料,提取研究区年降水量变化所蕴含的随机性和统计规律性,建立伪随机数与样品值的对应关系,从而对未来降水量进行预报,结果反映了预报时间内降水的总体特征,而不能精确到具体时间段。将这两种不同的方法用于同一地区年降水量的预报,对比结果,探其原因,分析其各自特点,进而得到更精确的预报值,对该地区水资源的研究有着重要的现实意义。 相似文献
144.
L. A. Ivanov L. A. Ivanova D. A. Ronzhina H. Ziegler K. Deigele P. D. Gunin V. I. P’yankov 《Russian Journal of Ecology》2007,38(3):155-160
The isotope ratios δ13C and δ15N and the contents of nitrogen, carbon, and mineral substances have been studied in the leaves of Ephedra sinica, Allium polyrhizum, and Stipa glareosa plants growing separately or together under arid conditions of the Gobi (Mongolia). The contents of nitrogen, mineral substances, and δ15N have proved to decrease when these species grow together, providing evidence that they compete for environmental resources. The nitrogen content decreases to the greatest extent in E. sinica due to the low competitiveness of this species. The direction of change in δ13C in E. sinica is opposite to that in A. polyrhizum and S. glareosa. Differences in physiological mechanisms of adaptation to stress between these species provides a basis for attributing them to different functional groups and for predicting the result of their competition upon changes in climatic conditions. 相似文献
145.
Ryoko Matsumoto Shigeru Suzuki Khisigjav Tsogtbaatar Susan E. Evans 《Die Naturwissenschaften》2009,96(2):233-242
New material of the enigmatic diapsid Khurendukhosaurus is described from the Mongolian type locality, Khuren Dukh, providing additional data on the vertebral column, pelvis, and
hind limb. It confirms the choristoderan status of the genus and permits a more detailed phylogenetic analysis that supports
a relationship between Khurendukhosaurus and the long-necked Asian Hyphalosauridae. The existence of tall caudal neural spines implies that Khurendukhosaurus was a deep-tailed swimmer. This and the open sacral costocentral sutures suggest a primarily aquatic lifestyle.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Institutional abbreviations MNHN BL, Museum National d’Histoire Naturelle, Paris, France; MPC, Mongolian Paleontological Center; PIN, Paleontologicheski
Institut, Akademii Nauk, Moscow; HMNS, Hayashibara Museum of Natural Sciences, Okayama, Japan. 相似文献
146.
以资源、能源为依托的工业结构和粗放的增长方式是内蒙古工业的主要特点,也是实现节能减排目标的瓶颈。通过淘汰落后生产能力、加快接续产业发展、推动资源型产业发展高端和集成产品、促进节能减排技术的研发和应用、发展循环经济以及建立配套的政策、法规体系,力促内蒙古工业实现节能减排目标,走出一条资源节约与环境友好的新型发展道路。 相似文献
147.
Chunyan Liu Jirko Holst Zhisheng Yao Nicolas Brüggemann Klaus Butterbach-Bahl Shenghui Han Xingguo Han Xunhua Zheng 《Agriculture, ecosystems & environment》2009,134(1-2):136-142
We investigated nitric oxide (NO) fluxes at a summer and a winter sheepfold in the Baiyinxile livestock farm, near Xilinhot, Inner Mongolia, which are a typical feature of the regional husbandry. Using a manual static opaque chamber/chemiluminescence measuring system, we intermittently observed fluxes in the summer sheepfold between May 28th and September 26th 2005 and in both winter and summer sheepfolds between March 8th and October 18th 2006. During these periods, mean NO emissions (±S.E., in terms of mass of nitrogen) were 124.0 ± 28.7, 134.6 ± 23.3 (summer sheepfold) and 214.4 ± 79.6 μg NO–N m−2 h−1 (winter sheepfold), respectively, and thus, three magnitudes higher than observed steppe NO emissions in the same region. The NO fluxes were not significantly different between the 2 years, but in summer they were much higher than in spring (p < 0.05). Temperature and moisture of the faeces layer significantly regulated the NO fluxes (p < 0.01). The direct NO emission factor (EF) for faeces and urine excreted in the sheepfolds was 0.7 g NO–Nemitted kg−1 Nexcreted, which was almost 37 times lower than a recently reported N2O EF. We estimated the total NO emission from the sheepfolds of the Baiyinxile livestock farm to be 1.82 ± 0.43 tons NO–N year−1, which accounts to approximately 12.3% of the total NO emission from this steppe region. With the rapid increase of livestock numbers, sheepfold NO emissions may further increase and contribute to high N deposition in confined areas around sheepfolds. 相似文献
148.
内蒙古生态环境敏感性综合评价 总被引:7,自引:0,他引:7
针对内蒙古土地沙化、土壤侵蚀、土壤盐渍化和生物多样性减少等区域自然环境演变过程中出现的生态问题,采用遥感和地理信息系统技术,构建敏感性评价指标体系与评价模型,对内蒙古生态环境敏感性进行综合研究,定量揭示研究区生态环境敏感性程度和空间分布特征.结果表明:土地沙化不敏感区、极敏感区分别占研究区面积35.9%和10.1%;土地沙化敏感性等级高的区域集中分布在内蒙古辖区内主要沙漠边缘和沙地;土壤基质多为沙粒、冬春季节多大风且植被覆盖度较低是土地容易发生沙化的主要原因.土壤侵蚀轻度、中度和高度敏感区分别占研究区面积的43.9%、30.2%和19.2%;受降水空间差异影响,土壤侵蚀敏感性等级自东南向西北呈逐步下降趋势.土壤盐渍化不敏感区、极敏感区分别占研究区面积的57.6%和14.6%,盐渍化明显地区主要分布在内蒙古西北部和东部;蒸发量远大于降水量,人类活动影响较明显,是土壤盐渍化高发的主要原因.生境不敏感、高度和极敏感区分别占研究区面积的30.5%、25.1%和10.6%,敏感性等级高的区域主要分布在大小兴安岭地区;这些区域水热条件相对较好,植被覆盖度高,物种数量较为丰富,是生物多样性重点保护区域.综合生态环境高度和极敏感区分别占研究区面积的27.9%和9.6%;敏感性等级高的区域位于内蒙古中北部,等级较低的区域位于内蒙古西北、东北和东南部. 相似文献
149.
Nesting biodiversity conservation into landscape management 总被引:3,自引:0,他引:3
Eduardo R. Fuentes-Quezada Nikhil Sekhran and Arundhati Kunte-Pant 《Natural resources forum》2000,24(2):83-95
There is universal recognition that biological diversity (biodiversity) is being lost at an alarming rate. The costs and risks of these losses for humanity are still not fully understood, but are believed to be very significant. While much is being achieved through conservation programmes, the task of addressing the current crisis remains complex, particularly as there are significant biological, social and economic challenges to nesting conservation objectives into land-use management. This paper emphasizes the socio-economic challenges, wherein a central issue is that of equitably sharing the costs and benefits of conservation among all beneficiaries, nationally and internationally. The world's biological heritage supplies mankind with a number of ecological goods and services, which have attached direct use values, indirect use values, existence values and option values. Currently, only a few direct values are tangible and here much remains to be done to capture effectively and distribute equitably the benefits arising from the other values. The paper discusses three instances where some of these challenges are being addressed, in Belize, Pakistan and Mongolia. Finally, the paper discusses the need for additional mechanisms that will help meet the challenge of establishing and maintaining conservation arrangements in the landscapes of developing countries, where much of the most threatened biota is found. 相似文献
150.
在农业废水产生量较大的秋浇期,选取14条引水和排水渠中的灌溉引水和秋浇退水进行盐份含量及组分分析,并针对重点渠段进行了45d 的连续监测.结果发现,在各引水渠中盐分含量都较低,全盐量基本在300mg·L-1左右.排水渠中全盐量较引水渠中有大幅升高,其中第8灌域与第9灌域的排干渠中的全盐量达到 6000mg·L-1以上.水质综合分析表明,灌溉后退水都为盐碱水和重盐碱水.同时,排水渠中高含盐量是随着灌区的秋浇活动而持续发生的,并且与灌溉引水量成比例关系.研究表明,内蒙古农业灌区的秋浇活动是导致乌粱素海以及黄河中下游水中盐分含量过高的主要原因之一. 相似文献