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231.
日本战后农业的现代化经历了一个同欧美发达国家农业现代化不同的过程。日本的现代农业以其亚洲型模式、资本与技术的集约性、小农规模经营和广泛的兼业化发展为特色。日本由传统农业平和地转变与过渡为现代农业的路子,为亚洲各国的农业现代化提供了参照和借鉴。 相似文献
232.
分析了1997年11 ̄12月在广东台山市三合镇附近发生的最大震级为4.1级小震群的活动特征、地质构造背景和震源机制解,并将其与1970年7 ̄12月发生的最大震级为4.0级的台山震群进行了对比,计算了两次小震群的序列特征参数,结果表明,1997年震群具有前兆震群的某些特征。 相似文献
233.
This contribution deals with the properties of small-scale magnetic elements in plages. Spectro-polarimetric observations, obtained with the highest possible spatial resolution with the German solar telescopes at the Observatorio del Teide on Tenerife, were analysed. We conclude from the spread of line parameters measured in the Stokes I and V profiles of Fe I and Fe II lines that a wide range of magnetic properties is realised in the solar atmosphere. The flow velocities in small-scale magnetic flux tubes, deduced from the zero-crossing of the V profiles at high spatial resolution, show a fluctuation of v
Doppler = 580 m s-1. This is substantially smaller than the turbulent broadening velocities of v
Doppler = 2 – 3 km s–1 commonly derived by fitting V profiles from flux tube models to low spatial resolution data, e.g. from a Fourier Transform Spectrometer. Attempts to explain the high resolution I and V profiles by models of hydrostatic flux tubes are discussed. It appears impossible to accomplish agreement between the modeled and observed radiation of lines with strong and weak magnetic sensitivity at the same time. We suggest a scenario in which small-scale magnetic elements possess substructure and are dynamic, with gas flows and magnetic field strengths varying in space and time. 相似文献
234.
The first systematic model series of hulls with small waterplane area (both single hulls and twin-hulls) was designed and tested in Krylov Shipbuilding Research Institute in the middle of the 1980's. The series was intended to cover a broad range of Froude numbers, hull aspect ratios, design drafts, and spacing between hulls. In the present paper, these test results are re-analyzed by accounting for the scale effect in the form drag, obtained from the comparison with test data of larger out-of-series models. Illustrative results are also given for the influence of the cross-section hull shape, strut configuration, and shifted hulls on the residual resistance and for dynamic trim and draft. Some data are compared with those of the later series tests of twin-hull models with small waterplane area carried out in HSVA, Germany. Factors influencing the residual resistance of ships of this type are discussed. 相似文献
235.
黄海小拟哲水蚤(Paracalanus parvus)丰度的季节变化 总被引:1,自引:0,他引:1
根据2001年3、5、6、7、8、11月黄海6个航次的大容量采水器(59L)中浮游动物的样品资料,对小拟哲水蚤无节幼体及该种桡足幼体和成体丰度的时空分布格局进行了研究。结果表明,小拟哲水蚤桡足幼体和成体3月份在整个黄海测区内的丰度较低;5月份除山东半岛南岸三个高值站位,外海相对比近岸高;6、7月份的丰度水平最高,7月份航次中,丰度最高的站位可达10555ind/m3,整个测区内,海州湾内侧高于外侧;8月份,测区内的丰度分布相对均匀,丰度较低;11月份,测区小拟哲水蚤的分布相对也比较均匀。小拟哲水蚤无节幼体的丰度在黄海测区内的分布格局与该种桡足幼体及成体丰度的分布格局在3、5、6、7月份比较吻合,在8、11月份吻合程度较差。不同月份小拟哲水蚤的分布与温度、盐度、叶绿素a的关系不尽相同;其受温度的影响相对较大,受盐度、叶绿素a影响较小。 相似文献
236.
一种纤毛虫的分类及形态研究
——寄生于牙鲆体表溃烂组织中的指状拟舟虫 总被引:5,自引:0,他引:5
报道从牙鲆(Paralichthys
olivaceus)体表溃烂组织分离的一种纤毛虫,通过活体观察、扫描电镜、蛋白银染色法、银浸法,对其形态学及纤毛图式做了研究。经鉴定,该纤毛虫为指状拟舟虫(Paralembus
digitiformis Kahl,1933),隶属于寡膜纲、盾纤目、嗜污科、拟舟虫属。这是指状拟舟虫在牙鲆上兼性寄生的首次报道。 相似文献
237.
The Falkland Islands has successfully met many challenges in the management and development of its fisheries resources over the last 20 years. To meet a new set of challenges the current licensing system based on the allocation of non-transferable, variable duration licences to individual vessels is being replaced by a system of long-term individual transferable rights owned by Falkland Islanders. The anticipated gains are enhanced economic performance of the sector because fishing businesses have increased security and flexibility, rapid diversification from harvesting into value-added activities and increased international competitiveness as poorly performing companies sell rights to well performing companies. Implementing a rights-based regime in a small coastal state is challenging. Thin markets for rights, a desire to maintain local control of fishing rights, and a dependence on foreign direct investment in the fisheries sector are key considerations in the design of an effective and efficient management regime. Starting operation in 2006/07, the new rights-based management system provides a model for small coastal states or small industrial fisheries that previously had considered rights-based systems too complex to implement and administer, despite the inherent advantages of rights-based management. 相似文献
238.
239.
《Geoforum》2016
Remoteness is a complex notion. A remote place implies a distant site with reference to where the one person positing such a qualification is located. However, it would be difficult to indicate how distant or how far a place would be, in order for it to be labeled as remote. The goal of this article is to contribute to the understanding of two components of remoteness: the absolute and the relative dimensions, and to shed light on the framing of remoteness. The premise is that the very notion of remoteness has not disappeared but is continually receiving new meanings. Remoteness has been redefined, re-signified and relocated in our minds and practices. 相似文献
240.
The diet of the Barn Owl (Tyto alba) is well known in different habitats but a lack of data persists for arid and subarid environments. We provide preliminary information on food selection of barn owls in Tunisia by the analysis of the composition of pellets. The diet consists largely of rodents and the three-toed Jerboa (Jaculus jaculus) that accounted for more than 50% of total prey biomass. Results suggest that barn owls show a nonrandom tendency toward rodent species especially small and young individuals. 相似文献