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851.
海洋环境无线传感器网络监测体系与应用技术研究 总被引:1,自引:0,他引:1
针对目前海洋环境监测中急需解决的主要技术问题.对海洋环境无线传感器网络监测的体系结构进行了研究,通过对Crossbow无线传感器网络的拓扑结构和软件架构进行分析与试验.提出其技术优势和有待解决的应 用问题. 相似文献
852.
853.
854.
南海北部神狐海域天然气水合物形成及分布的地质因素 总被引:6,自引:0,他引:6
从天然气水合物发育的地质构造条件、沉积条件、气源条件、温压条件等分析了神狐海域影响水合物形成及分布的地质因素.指出神狐海域处在洋陆壳的过渡带上,断裂-褶皱构造及流体底辟构造发育,对水合物的形成具有重要的控制作用.受等深流和海底滑塌双重作用,研究区沉积异常体发育,沉积厚度大、沉积速率高,有利于水合物发育.通过对神狐海域附近钻探结果及区内地质调查站位资料的分析表明:目标区具有含巨量的生物气和热成因气资源潜力,具备形成天然气水合物的气源条件,气源为文昌-恩平组烃源岩.此外,受热流值北高南低的分布格局的影响,神狐海域BSR埋深也表现为北部浅南部深,且BSR分布区整体处在天然气水合物稳定存在的温压范围内,满足水合物形成及保存所需的温压条件.神狐海域的地质构造条件、沉积特征、气源条件、温压条件等都非常有利于天然气水合物发育. 相似文献
855.
1998年季风爆发期南海大气边界层的日变化 总被引:1,自引:0,他引:1
在南海尚未有关于海洋大气边界层结构日变化方面的研究.研究海洋大气边界层,有利于我们更好地研究海洋表层结构变化影响机制,对发生在海洋大气边界层上的过程进行预测预报.因此了解南海海洋大气边界层的结构特征,对于我们进一步了解南海天气尺度海气相互作用有非常重要的意义.通过对1998年在南海南部(6°15′N,110°E)和南海北部(20°29′39″N,116°57′48″E)的南海季风试验中定点科考船释放一天四次的探空观测资料分析得出,季风爆发前海洋大气边界层存在规则的日变化,在中午达到深厚.季风爆发后南海北部大气边界层日变化消失,南海南部依然明显.分析表明对其日变化起重要影响的是短波辐射;潜热输送对大气边界层高度日变化影响不大.与大气边界层厚度日变化相对应,南海南部边界层内水汽日变化明显,而南海北部较不明显. 相似文献
856.
The relation between otolith weight (OW) and the age of marine fish is studied. A total of 222 individuals of bighead white
croaker, Pennahia macrocephalus were sampled seasonally in the mouth of the Beibu Gulf, the South China Sea, in 2007. Since there are no significant differences
in sagittal OW between otolith in pairs (P≥0.05), the undamaged left sagittal otolith is used for age determination. The highest correlations among standard length,
OW and fish ages are confirmed by linear, exponential and multinomial regression. Results show that sagittal OW overlaps only
occasionally among age groups, and to individuals with similar standard length, the older and slower-growing fish has a heavier
otolith because of the continued otolith material deposition. There are differences in sagittal OW among different age groups
and significant positive linear relationship with age (P<0.05). The age readings can be verified by plotting the sagittal OW versus the standard length for age groups, and the individuals
with similar standard length but in different ages can be separated by sagittal OW frequency analysis. Mostly, the predicted
ages using the regression between sagittal OW and ages are closed to the observed ages by counting annulus on scale. It indicates
that the sagittal OW analysis is a useful technique for validating the accuracy of age determination by annuli counts, especially
for individuals of similar size. Furthermore, the technique is applied for Pennahia macrocephalus with discussion in this paper.
Supported by the National Natural Science Foundation of China (No. 30771653) and Bureau of Fisheries, Ministry of Agriculture 相似文献
857.
Expression of putative zinc-finger protein lcn61 gene in lymphocystis disease virus China (LCDV-cn) genome 总被引:1,自引:0,他引:1
An open reading frame (lcn61) of lymphocystis disease virus China (LCDV-cn), probably responsible for encoding putative zinc-finger proteins was amplified
and inserted into pET24a (+) vector. Then it expressed in E. coli BL21 (DE3), and His-tag fusion protein of high yield was obtained. It was found that the fusion protein existed in E. coli mainly as inclusion bodies. The bioinformatics analysis indicates that LCN61 is C2H2 type zinc-finger protein containing
four C2H2 zinc-finger motifs. This work provides a theory for functional research of lcn61 gene.
Supported by High Technology Research and Development Program of China (863 Program, No. 2006AA100309) 相似文献
858.
Livelihood strategy change and land use change —Case of Danzam Village in upper Dadu River watershed, Tibetan Plateau of China 总被引:2,自引:1,他引:1
Land use change in rural China since the 1980s, induced by institution reforms, urbanization, industrialization and population
increase, has received more attention. However, case studies on how institution reforms affect farmers’ livelihood strategies
and drive land use change are scarce. By means of cropland plots investigations and interviews with farmers, this study examines
livelihood strategy change and land use change in Danzam Village of Jinchuan County in the upper Dadu River watershed, eastern
Tibetan Plateau, China. The results show that, during the collective system period, as surplus labor forces could not be transferred
to the secondary and tertiary industries, they had to choose agricultural involution as their livelihood strategy, then the
farmers had to produce more grains by land reclamation, increasing multiple cropping index, improving input of labor, fertilizer,
pesticide and adopting advanced agricultural techniques. During the household responsibility system period, as labors being
transferred to the secondary and tertiary industries, farmers chose livelihood diversification strategy. Therefore, labor
input to grain planting was greatly reduced, which drove the transformation of grain to horticulture, vegetable or wasteland
and decrease of multiple cropping index. This study provides a new insight into understanding linkages among institution reforms,
livelihood strategy of smallholders and land use change in rural China.
Foundation item: Under the auspices of National Natural Science Foundation of China (No. 40601006, 40471009), National Basic
Research Program of China (No. 2005CB422006) 相似文献
859.
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????AR?????????????????????????????????????AIC?????AR????????????????????,AR??4?????????????????????AR(4)???????????δ??10??????????????????? 相似文献
860.
雪宝顶矿床位于四川省的松潘甘孜造山带中,以出产大颗粒含W-Sn-Be-F-P的矿物而闻名,前人对该矿床已经开展了大量的研究,但缺乏对粗粒矿物的主次痕量元素研究.本次研究采用X射线荧光光谱(XRF)、电子探针(EMPA)和电感耦合等离子体质谱(ICP-MS)技术对矿床中各矿物的主次痕量元素进行测试分析.结果显示,雪宝顶矿... 相似文献