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991.
固体矿产勘查及矿产资源/储量分类的一些新规定及有关问题讨论 总被引:2,自引:1,他引:1
对固体矿产勘查工作阶段的划分及固体矿产资源/储量分类中的有关规定作了进一步的解释,并对“地质可靠程度”等问题作了讨论。 相似文献
992.
With the decline of fish stocks, the proportions of economically important invertebrates like crustaceans and cephalopods have increased in the Bohai Sea. The community structure and trophic level of economically important invertebrates were analyzed using the bottom trawl survey data collected by the Yellow Sea Fisheries Research Institute in the Bohai Sea in May and August of 1958–1959, 1982, 1992–1993, 2004, 2009 and 2015. A total of 37 species of economically important invertebrates, belonging to 5 orders, 24 families, were captured. The biomass densities of economically important invertebrates in the Bohai Sea displayed an overall downward trend from 1982 to 2015. Oratosquilla oratoria and Loligo spp. were the most dominant species in the past 30 years, the biomass proportion of O. oratoria increased gradually in both May and August from 1982 to 2015. Moreover,biodiversity indices of economically important invertebrates in the Bohai Sea appeared to decline from 1982 to2004 and then increased in 2015. Similarly, the mean trophic level of economically important invertebrates declined from 1982 to 2004 and increased slightly in 2015. Overall, although the proportions of invertebrates have increased, the biomass densities in the Bohai Sea have displayed an overall downward trend from 1982 to 2015.The increases in the biodiversity and trophic level of economically important invertebrates after the 2000 s,possibly benefit from stock enhancement projects implemented by governments at different levels and national fishery management measures such as the "double-control" of the total number and engine power of fishing vessels and summer moratorium of fishing. 相似文献
993.
区域经济弹性视角下辽宁老工业基地经济振兴过程分析 总被引:10,自引:6,他引:4
区域经济弹性概念对分析老工业基地演变过程有独特的理论价值。依据经济增速划分1990~2015年辽宁老工业基地经济周期,通过构建反事实函数测度不同阶段城市和分产业经济抵抗力和恢复力,揭示了区域经济弹性的演化特征,反映了辽宁老工业基地经济振兴过程,结果发现:同一经济周期中抵抗力和恢复力之间存在负相关关系,抵抗力低受冲击影响严重的城市在随后的经济振兴过程中经济恢复发展好,存在“创造性破坏”过程;区域经济弹性是一个不断演化的过程,区域对冲击的抵抗力水平受前一经济周期恢复力的影响,区域经济弹性在引起区域应对冲击能力的变化同时其自身也因此而发生改变;辽宁老工业基地的经济振兴经历了衰退-恢复-下滑的波动历程,呈现倒“N”型,其面对冲击扰动的抵抗力较低,第二产业更易受到冲击影响,第三产业抵抗力相对较高,老工业基地长期存在路径依赖、制度锁定现象,结构性体制性问题严重,突破能力弱,过度依赖传统重化工业,新兴产业发展缓慢,现代服务业发展严重滞后。针对老工业基地演变过程的规律特征,提出了辽宁老工业基地经济振兴的对策建议。 相似文献
994.
Sonar image segmentation based on GMRF and level-set models 总被引:2,自引:0,他引:2
We propose two new level-set models to address the segmentation problem in sonar images. Local texture features, extracted using the Gauss-Markov random field model, are integrated into level-set energy functions to dynamically select regions of interest. Then, new two-phase level-set and multiphase level-set models are obtained by minimizing each new energy function, and the selection of model parameters is analyzed. The proposed models do not require re-initialization, which is usually a very costly procedure. Segmentation experiments on both synthetic and real sonar images show that the proposed two level-set models are accurate and robust when they are applied to noisy sonar images. 相似文献
995.
利用强流脉冲电子束(high-current pulsed electron beam,HCPEB)技术对多晶纯Ni进行了辐照处理,采用透射电子显微镜详细分析了辐照诱发的缺陷结构.HCPEB辐照后,纯镍表层积聚了幅值极大的残余应力,沿{111}晶面形成了稠密的位错墙及孪晶结构,另外还形成了大量的包括位错圈、堆垛层错四面体(SFT)及孔洞在内的空位簇缺陷.SFT缺陷的数量远高于其他空位簇缺陷,其周围区域位错密度很低.孔洞缺陷主要出现在SFT密集区域.HCPEB瞬间的加热和冷却诱发的幅值极大的应力和极高的应变 相似文献
996.
To investigate the feasibility and methodology of new generation sea surface temperature (SST) maps that combine various satellite
measurements, we have quantitatively evaluated SST availabilities of NOAA AVHRR (National Oceanic and Atmospheric Administration,
Advanced Very High Resolution Radiometer), GMS S-VISSR (Geostationary Meteorological Satellite, Stretched-Visible Infrared
Spin Scan Radiometer) and TRMM MI (Tropical Rainfall Measuring Mission, Microwave Imager: TMI), during the one-year period
from October 1999 to September 2000. The advantage of satellite microwave SST measurements is the ability to penetrate the
clouds that contaminate satellite infrared measurements. Daily SST availabilities were calculated in the overlapping coverage
from 20°N to 38°N and 120°E to 160°E. The annual-mean SST availabilities of AVHRR, S-VISSR and TMI are 48%, 56% and 78%, respectively.
There are large seasonal variations in the availabilities of infrared measurements. The latitude-time plots of one-degree
zonal mean SST availabilities of S-VISSR and TMI in the region from 38°S to 38°N and 80°E to 160°W show significant zonal
variations, which are influenced by the atmospheric circulation such as the Subtropical High and the Intertropical Convergence
Zone. The SST availabilities of S-VISSR and TMI in the five selected regions have large regional variations, ranging from
35% to 74% and 62% to 88% for S-VISSR and TMI, respectively. The present statistical analyses of SST availabilities in the
infrared and microwave measurements indicate that 1) a daily cloud-free high-spatial resolution may be achieved by merging
various SST measurements since their deficiencies compensate each other, and 2) nevertheless, it is necessary to take account
of the seasonal and regional variations of SST availabilities of different satellite sensors for the development of merging
technology.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
997.
费歇判别法识别大孔道 总被引:1,自引:1,他引:0
根据测井曲线,运用费歇准则导出了识别砂岩油层大孔道的判别函数,判别函数是测井曲线的线性组合。利用此判别函数实现了在微机上用费歇方法识别大孔道的问题。针对大庆某地区一模型,取得了令人满意的结果,正确率达85%以上,结果表明,费歇判别法是识别大孔道的行之有效的方法。 相似文献
998.
就2007年6月3日云南宁洱6.4级地震,云南省近50口水位观测井的同震后效及特征进行分析研究。结果表明:水位同震震时效应后的水位突升、突降、固体潮日变畸形是水位后效的显著特征。滇西北东向断裂带及小江断裂带很可能是近年后继中强震发生的危险区域。 相似文献
999.
福建省地震局GPS观测技术应用于1992年开始,起步早,发展快。本文阐述了福建省地震局在“九五”、“十五”期间以GPS观测技术为主的福建地壳运动观测网络的建设历程,重点对“十一五”期间正在进行的“福建省GNSS连续观测台网”项目进行了介绍。由于所处地理位置独特,福建GPS观测在地震研究中得到了广泛的应用。本文对福建GPS观测在地震应用中已经取得的成果进行了简述,并利用福建地壳运动观测网络的观测资料,分析了汶川8.0级地震对福建区域应力场的影响。“十一五”结束后,福建GNSS连续观测站达到41个,将成为我国大陆GNSS连续观测站最多、密度最大的省份之一,这将有力地推动地球科学创新和地震预报攻关。 相似文献
1000.
Germination responses of Medicago ruthenica seeds to salinity,alkalinity, and temperature 总被引:2,自引:0,他引:2
To determine the effects of and the interactions between salinity and temperature, and alkalinity and temperature, we conducted three germination tests of Medicago ruthenica (L.) Sojak cv. ‘Zhilixing’ seeds in growth chambers. In experiment 1, the seeds were placed at a range of temperatures (5, 10, 15, 20, 25, 30, 35, or 40 °C), and in experiments 2 and 3, we varied the salinity (0, 50, 100, 150, 200, or 250 mM NaCl) and alkalinity (1, 5, 10, 15, 20, or 25 mM Na2CO3), respectively, within three ranges of alternating temperatures (10–20, 15–25, and 20–30 °C). The seeds of M. ruthenica (L.) Sojak cv. ‘Zhilixing’ showed high percentage germination at all temperatures, except for 5 °C. Seeds germinated well at low NaCl and Na2CO3 concentrations under all three alternating temperature regimes. Approximately half the seeds germinated at high salinity and alkalinity at 15–25 °C, whereas the ungerminated seeds germinated when the high-saline and alkaline stresses were removed. These results suggest that M. ruthenica (L.) Sojak cv. ‘Zhilixing’ has potential utility as a forage legume in saline and alkaline environments. 相似文献