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451.
地勘单位实现企业化,经营者分配改革势在必行.对地勘单位经营者实行年薪制的必要性、年薪水平的确定、年薪的考核兑现等进行了探讨. 相似文献
452.
Wetlands in China: Feature, value and protection 总被引:1,自引:1,他引:1
The estimated total area of wetland in China is more than 25.9 million hectares including about 11.9 million hectares of marshes
and bogs, 9.1 million hectares of lake and about 2.2 million hectares of coastal salt marshes and mudflats. The area of wetland
is equivalent to 2.7% of the land surface. China also has 2.7 million hectares of shallow sea water (less 5m in depth at low
tide). Marshes and bogs are equivalent 1.3% of the land surface. Only three provinces (regions)—Qinghai, Xizang (Tibet) and
Heilongjiang — have a larger total area of marsh and bog. According to the structure, type and development of wetland in different
river basins, wetland can be classified nine main regions. The experiments indicate that the coefficient of the marsh to regulate
flood is similar to that of lakes. Wetlands occupy 17.8% of the Sanjiang Plain area, the annual carbon contribution is 0.78
× 104t. Carbon released from marsh soil return into atmosphere is 3.95 × 106t/a. At present there is a sharp contradiction between population growth and natural resources shortage, causing wetland to
be exerted with huge pressures and serious threats.
Foundation item: Under the auspices of the Key B Item of the Chinese Academy of Sciences (KZ951-B1-201-02).
Biography: LU Xian-guo (1957 —), male, a native of Changchun City, Jilin Provice, professor. His research interests include
wetland process and environmental effect. 相似文献
453.
Ten clonal units of Carex pseudocuraica growing in four different microhabitats (perennial flooded ditch water, perennial flooded ditch sediment, seasonal flooded
ditch sediment and perennial flooded soil) of the Sanjiang Plain, Northeast China, were collected randomly for phenotypic
plasticity analysis. Iron content, chemical and physical properties of substrates and the total Fe of nine plant modules were
measured as well. The results show that the performance of the C. pseudocuraica is affected by the microhabitat, with the greatest performance score in perennial flooded ditch water, and the lowest in
perennial flooded soil. The biomass allocation indexes indicate that much more mass is allocated to stems and roots to expand
colonization area. The distribution of the total Fe in plant modules appears as pyramids from the tip to the root, while marked
differences are observed in the distribution proportion of stems, tillering nodes and roots that are allometrically growing.
Iron transfer from substrates to the plant is mainly controlled by the substrate type. The differences of iron distribution
and transfer in the plant in different microhabitats are attributed to the iron contents of the substrates as well as the
phenotypic plasticity of the plant. 相似文献
454.
Yingxia Lu Baosheng Li Xiaohao Wen Shifan Qiu Fengnian Wang Dongfeng Niu Zhiwen Li 《中国地理科学(英文版)》2010,20(3):243-251
The upmost segment(Holocene series)of the Milanggouwan stratigraphic section(MGS1)in the Salawusu River valley shows 11 sedimentary cycles of dune sands and fluvio-lacustrine facies,or dune sands and paleosols.The analysis of the magnetic susceptibility of this segment suggests that there are 11 magnetic susceptibility cycles with the value alternating from low to high,in which the layers of the dune sands correspond to the lower value of the magnetic susceptibility and the layers of fluvio-lacustrine facies and paleosols correspond to the higher peaks.The study reveals that the low and high magnetic susceptibility values indicate the climate dominated by cold-arid winter monsoon and warm-humid summer monsoon of East Asia,respectively,and the study area has experienced at least 22 times of mil-lennial-centennial scales climate alternation from the cold-arid to the warm-humid during the Holocene.In terms of the time and the climate nature,the variations basically correspond to those of the North Atlantic and some records of cold-warm changes in China as well.They might be caused by the alternation of winter and summer monsoons in the Mu Us Desert induced by global climate fluctuations in the Holocene. 相似文献
455.
榆林长城沿线处于环境变化敏感带,其风沙滩区沉积剖面的磁化率和粒度分析结果显示,该区全新世早期11 500~10 000 a BP随着全球气候的逐渐转暖,磁化率、黏粒和粉沙含量逐渐增高;全新世中期的10 000~4 500 a BP气候相对比较湿润,植被覆盖度增大,风沙活动减弱,地表沉积物当中粉沙和黏土成分含量显著增大,风化成壤作用增强,地表发育沙质弱古土壤;全新世中期后段的4 500~3 000 a BP期间,气候以比较温和湿润为主,但在4 200~4 000 a BP出现一个气候干旱事件,风沙活动强烈;近3 000 a以来,气候显著干旱化,波动频繁,地表风沙沉积物显著变粗,表现出有5次沙漠扩张。该区生态环境演化、人文历史变迁基本上是自然因素与人为活动综合作用的结果,以自然演化为主,近代人为因素对环境变化起着加强和放大作用。 相似文献
456.
以江山—绍兴断裂带北东端桐树林~潘村韧性剪切带中的金矿特征为例,阐述韧性剪切带与金矿化的关系,认为该韧性剪切带对金矿的成矿和窑矿具明显的控制作用,剪切带与神功期石英闪长岩的接触部位是金矿分布的有利地段。剪切带内浅色蚀变带和糜棱岩带及成群出现的含碎裂状黄铁矿的石英脉是良好的找金标志。根据韧性剪切带具有长期多次活动、产状变化复杂的特点,今后应注意在剪切带深部寻找工业矿体。 相似文献
457.
卢玉东 《地球科学与环境学报》1997,(Z1)
传统的渗流模型研究中,忽略了渗流场中水压力传递的时效性。本文针对潜水含水层井流问题,分析了井流场的特征。在前人研究的基础上,作者详尽地推导了上部入渗补给为常量情况下的降落漏斗半径和水压力传递速度与时间的关系式,并对某电厂水源地进行了计算。 相似文献
458.
??ITRF2008??????й???????5??IGS??????WUHN??BJFS??URUM??KUNM??SHAO??2012??????????????TriP?????????????????????????С??????????????????????????????????????????н?????????????????????????????????GAMIT/GLOBK????????????????????з?????????ж???????????????й??????IGS???????????д??????????????????????????????????????????????????URUM??KUNM??BJFS??SHAO?????????????????????BPPL+WN????WUHN??????N??E??U????????????????з?????????????BPPL+WN??FN+WN??PL+WN??????????BPPL+WN??????????а???????????????????????????2 mm??BPPL???????WN??????1/10???????0.28??0.89 mm????????????????С???????????????????????????????????С??????TriP?????????????????????????????????????????????????? 相似文献
459.
提出采用变系数回归模型提取连续GPS坐标序列中包含的振幅时变季节性信号。对模拟数据及实际GPS坐标序列两组数据的分析结果表明,变系数回归模型在提取GPS坐标序列季节信号方面比传统模型更有效。经处理,GPS坐标序列能获得更合理的速度及噪声估计。 相似文献
460.
根据实际应用研制制冷控制系统,该系统采用温度测量、PID控制及PWM脉宽调制等技术实现了对目标对象的制冷处理,具有一定的应用价值。 相似文献