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831.
北方农牧交错带濒危少数民族语地名规模不断增加,少数民族语地名文化脆弱性日益突出,可持续发展尤为堪忧。地名是由多要素构成的开放性文化系统。因此,如何从系统脆弱性角度将以往对濒危少数民族语地名的定性研究扩展至脆弱程度的定量研究具有一定的理论与现实意义。引入脆弱性研究范式,基于大量实地考察和文献梳理,从敏感性、暴露度及恢复力的视角识别北方农牧交错带少数民族语地名文化脆弱性影响因素,构建脆弱性评价体系,讨论评价尺度和评价方法,并针对典型案例地展开实证研究。结果表明:案例地少数民族语地名文化敏感性和暴露度突出,恢复力较弱,脆弱性较明显。其脆弱性受地名文化系统内损性和外部扰动性因素的共同影响。其中,地方居民对少数民族语地名语源语义的错误认知,较高的汉语普及率和汉译少数民族语地名社会认同度,以及少数民族语地名意译的非准确化是脆弱性形成的重要驱动因子。其次,汉译用字和译音的简化和非标准化,较高的地名合并、更改及弃用比,较少的地名文献储备量,以及少数民族语使用群体规模的大幅下降也是较为重要的单指标因素。 相似文献
832.
Zhangyu Dong Zongming Wang Dianwei Liu Kaishan Song Lin Li Mingming Jia Zhi Ding 《Journal of the Indian Society of Remote Sensing》2014,42(3):569-576
Increasing interest in wetlands for environmental management requires an understanding of the location, spatial extent, and configuration of the resource. The National Wetlands Inventory is the most commonly used data source for this information. However, its accuracy is limited in some contexts, such as agricultural and forested wetlands. An large number of studies have mapped wetlands worldwide from the perspective of land use and land cover change. However, information on the actual wetland planting areas annually is limited, which greatly impacts ongoing research. In this case study of the West Songnen Plain, we developed a simple algorithm for the quick mapping of wetlands by utilizing their unique physical features, such as annual display of phenological land-cover change of exposed soils, shallow flooding water, and plants from multi-temporal Landsat images. Temporal variations of the Normalized Difference Vegetation Index (NDVI) and Land Surface Water Index (LSWI) derived from Landsat images in 2010 for wetlands at different growth stages were analyzed. Results show that during the ante-tillering phase, the NDVI value (above zero) is lower than the LSWI value of paddies because of flooding of shallow water; during the reproductive and ripening phases, the NDVI value is higher than the LSWI value (above zero); and during the post-harvest wetland planting phase, the NDVI value is still higher than the LSWI value, but the LSWI value is negative. Wetland areas can be detected using one or two images in the optimum time window. The algorithm based on the difference of NDVI and LSWI values derived from Landsat images was used to extract the actual wetland planting area. Validated alongside statistical data, the algorithm showed high accuracy. Therefore, this algorithm highlights the unique features of wetlands and can help in mapping the actual wetland area annually on a regional scale. Results further indicate that the new method has a classification accuracy of 92 %. In comparison, two traditional methods based on Landsat-7/ETM registered accuracy rates of only 83 % and 87 % respectively. 相似文献
833.
随着计算机技术的不断进步,用户界面设计---有效的人机交互策略变得更加重要。地理信息系统的发展要求其系统软件的设计者与开发者设计开发出更加人性化的用户界面,以提高不同领域、不同层次软件使用者的满意度。 相似文献
834.
835.
Ping Chen Dan Xia Boyuan Chen Lin Li Xiuzhong Li Tian-lin Dong 《Journal of Applied Geophysics》2011,73(3):261-266
Ray representation of electromagnetic resonance (reverberation) mode in subsurface circular cylindrical dielectric resonator (including void) is proposed. The modal ray path must be regular polygon or polystar. Travel time formulas for fundamental resonance multiples and the detecting conditions for non-exact-backscattering rays are derived. Simulation of time–distance curves of a modal hollow concrete block is generally concurred to the measured ground penetrating radar signal pattern. The proposed modeling method can be generalized to other resonant cavities with different profiles and provide a sound base for further applications of other more complicated geophysics science and engineering fields, particularly in ray-based tomography. 相似文献
836.
X. L. Sun X. G. Zhang J. L. Lin Z. X. Zhao D. W. Huang 《Australian Journal of Earth Sciences》2013,60(8):1163-1174
AbstractThe characteristics and distribution of clay minerals and their effects on reservoir quality in the Huagang sandstones in the Xihu Sag, East China Sea Basin were studied by using X-ray diffraction, casting thin-sections, scanning electron microscopy, electron microprobe analysis, fluid inclusion analysis, constant-rate mercury injection and nuclear magnetic resonance. Clay minerals consist of kaolinite, chlorite, illite and illite–smectite mixed layer (I/S); kaolinite forms from dissolved feldspars, chlorite occurs as clay coatings that are transformed from clay precursors owing to the flocculation of suspended detrital clays or the crystallisation of pore fluids, and illite forms from the illitisation of detrital smectite, authigenic kaolinite and K-feldspars. Clay distribution is controlled by sedimentary environments, burial history and lithologies. Typical reservoirs in the western sub-sag are thin and developed in braided river facies at relatively shallow burial depths with clays dominated by kaolinite. However, typical reservoirs in the central inversion tectonic zone are thicker and developed in a braided delta front facies at deeper burial depths with clays mainly consisting of chlorite, illite and I/S. High-quality reservoirs are characterised by coarse granularity, high quartz content and low clay content with widespread development of chlorite coatings that inhibit quartz cements at low temperatures. At higher temperatures, the high-quality reservoirs develop more pores providing growth space for quartz cements and result in the coexistence of chlorite coatings and quartz cements. The high-quality reservoirs are controlled by their lithological characteristics rather than chlorite coatings. Illite and I/S clays create severe damage to reservoirs by reducing the size and connectivity of pore-throats. 相似文献
837.
Regularities exist in fluid flows and can be represented by a set of constants. These constants are functions of the parameter of a probability distribution that exhibits resilience and stability under various flow conditions. Together, these regularities form a network and interact with each other, such that if one is known then the others can be determined from it. The regularities and their network explain the various fluid‐flow phenomena and can be used in analysis of rivers and streams. For example, they can be used as the basis to develop simple and efficient methods of discharge measurements as presented herein, which only require velocity sampling at a single point on a water surface or a few points on a single vertical. Because of their simplicity and the short time requirement, these methods can be easily automated for collecting discharge data in unsteady, high flows that are badly needed for real‐time flow forecasting and design of flood control structures, and for advancing the fundamental, scientific knowledge in hydrology. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
838.
Abstract In this study, the development of a moderate coastal storm with intense precipitation that occurred during 12–14 February 1993 is examined using a high‐resolution version of the Canadian Regional Finite‐element (RFE) model with more realistic physical representations. It is shown that the improved RFE model predicts well the coastal cyclogenesis events and also the distribution and intensity of heavy mixed precipitation (rain and snow) associated with the storm. It is found that the cyclogenesis takes place in response to the low‐level inshore advection of high‐θe air from the maritime boundary layer, and the approach of a mid‐level shortwave trough with a warm pool above that is previously associated with a decaying cyclone upstream. More rapid deepening of the cyclone ensues as intense precipitation falls along the warm and cold fronts near the cyclone centre. Diagnosis of the control and sensitivity simulations reveals that the low‐level inshore warm advection and the propagation of the stratospheric warm pool contribute more significantly to the surface pressure falls during the incipient stage, whereas the mid‐level shortwave trough plays an important role in the cyclogenesis at later stages. Overall, latent heat release accounts for about 50% of the cyclone's total deepening, in agreement with the presence of a moderate baroclinic environment and the generation of intense precipitation. The diabatic and kinematic structures near the rain‐snow boundary are examined to gain insight into the influence of melting snow on the cyclogenesis. It is shown that the improved RFE model reproduces well the rain‐snow boundary structures as previously observed. Moreover, a thermally indirect circulation (perturbation) can be seen in the vicinity of the rain‐snow boundary. It is found, however, that melting of snow tends to produce a weak negative or negligible impact on the cyclogenesis, as opposed to previous hypotheses. 相似文献
839.
Reproductive rate of a marine planktonic copepodLabidocera euchaeta Giesbrecht in Xiamen Harbor bor was studied during the period from April 1986 to August 1987. Results showed that rate of
egg production (F, eggs/(♀, d)) was positively correlated with temperature (T,oC) and body weight of spawning female (Wc, μgC) as:F=0.0637 (T−7)0.7445
Wc. Each month a maximum rate of egg production occurred at one of the five experimental temperatures (10°, 15°, 25°, and 30°C)
near the monthly mean field temperature. The available food density (P, μgC/ml) had significant effect on specific rate of egg production (Fc, %C ♀/d) as:Fc=0.1732 (P-0.0179)/P. The gross efficiency of egg production of ca 62% in carbon was independent of food density snd ingestion rate. Observations
on in situ egg production and hatching rate demonstrated that this species reproduces continuously all the year round, with
summer as its high reproductive season and winter a low one. Ten generations a year is also suggested based on the number
of the peaks of average population egg production rate. This agreed well with the result obtained from the generation-time
equations. Egg-laying pattern was also observed and discussed. 相似文献
840.
Beijing’ population has experienced a dramatic increase eversince the founding of the People’s Republic of China. Population
growthin Beijing can be broadly broken down into three major components:natural increase, immigration, and the growth of floating
population. Thecontinuous growth of Beijing’s population is closely linked with its centralized multi-function. The comprehensive
countermeasures to control Beijing’s population growth are proposed, for example, decentralizing economicfunctions, including
developing the suburbs, developing the metropolitan areaand creating counter-magnetic centers, reforming the administrative
and economic systems. 相似文献