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981.
982.
太阳辐射测量标准仅采取定期参加国际比对的溯源方法不能完全满足质量保证的要求。只有联合国际比对和期间核查的控制方法,才能确保测量标准的测量不确定度持续控制在误差允许范围之内。我国太阳辐射测量标准与世界辐射测量基准 (WRR) 比对结果的不确定度为0.17%,满足世界气象组织 (WMO) 要求,并达到世界先进水平。为了保证在两次国际周期比对间隔之间的准确可靠,并保证其处于良好置信度的校准状态,定期对测量标准的重复性和稳定性进行期间核查, 以图形记忆方式对太阳辐射测量标准的测量过程进行连续和长期的统计控制。通过期间核查,保证了太阳辐射测量标准的重复性不大于0.1%,年稳定性小于0.25%,未超出控制界限且分布呈随机状态,保证了测量过程处于稳定受控状态,满足建标要求。 相似文献
983.
Effect of salinity on survival,feeding behavior and growth of juvenile swimming crab P ortunus trituberculatus was investigated under 5 salinity levels of 5,10,20,30 and 40. The results show that the crab juveniles fed 2 or 3 times at the salinity 20 and 30,each lasted for about 25 minutes,for a total feeding time of 73.2±22.65 minutes per day. At these salinities,there were significantly higher in the frequency of feeding and in total feeding time than those at lower salinities of 5 and 10. All crab juveniles moulted when reared at a salinity of 20 during the 5 days duration of the experiment,which is significantly higher than those at other salinities. All juveniles survived at salinity 20,and the survivorship was not significantly different from that at 30,but was signif icantly higher than those at other salinities. The crab juveniles reared at a salinity of 20 had the highest value of food ration of 0.190 8±0.011 3 g/g BW,average body weight gain of 0.796±0.128 g,gain rate of 87%–96%,and food conversion ratio of 1.20±0.09. There was no significant difference in the values found between 20 and 30 but these values were significantly lower than that at the other salinities( P 0.05). Highest activities of digestive enzymes(Amylase,Protease,Lipase) and lowest activities of protective enzymes(SOD,PO,CAT) were also obtained on crab juveniles reared at salinity of 20. 相似文献
984.
985.
The dissolved organic carbon pool (DOC) is among the largest reservoir of reduced carbon on our planet. The demonstration that DOC polymers remain in assembly/dispersion equilibrium forming microscopic hydrogels has a broad range of critical implications. Previous studies estimate that 10% of DOC could be assembled as gels, yielding values of 7 × 1016 g of organic carbon present as microscopic hotspots of high substrate concentration. This huge mass of reduced carbon emphasizes the need to develop reliable methods to systematically investigate the budget of self-assembled marine gels (SAG), and their role in biogeochemical cycling. However, a quantitative method to measure SAG in seawater has not been available. Here we present the validation of a simple assay to measure the mass of organic carbon assembled as microgels in native seawater. This method is based on the ratio of Chlortetracycline (CTC) fluorescence quenching between Ca bound to non-assembled organic molecules and molecules assembled as microgels. This assay can be readily implemented on board using a low cost fluorometer and provisions to measure TOC. 相似文献
986.
3D coseismic Displacement of 2010 Darfield, New Zealand earthquake estimated from multi-aperture InSAR and D-InSAR measurements 总被引:2,自引:1,他引:1
Differential interferometric synthetic aperture radar (D-InSAR) measures ground deformation only along the line-of-sight (LOS) of the radar, which limits the capability of D-InSAR in investigating the surface damages and the focus mechanisms of earthquakes. We do a three-dimensional (3D) decomposition of the coseismic displacement of the Darfield, New Zealand earthquake that occurred on 3 September 2010 by exploiting the Multi-Aperture InSAR (MAI) and D-InSAR measurements from both ascending and descending L-band PALSAR data. Due to the dispersive nature of the ionosphere and the slight Doppler shift between the forward- and backward-looking interferograms, the ionospheric effects can be more serious in MAI measurements than in D-InSAR. We propose mitigating the ionospheric effects in the MAI processing with the directional filtering and interpolation procedure that has been applied in Offset-tracking. The rupture revealed by the 3D surface displacement fits closely to the Greendale fault, which is believed to be responsible for the earthquake. The horizontal ground motions, mostly eastwards in the hanging wall and westwards in the footwall, reached up to 2.5 m and are anti-symmetric with respect to the Greendale fault. Up to 2.5 m subsidence occurred in the hanging wall, while uplift is found in the footwall with an extreme case of 1.6 m in the far left of the fault. This makes us conclude that the Greendale fault is a normal and dextral strike-slip. It is seen that the MAI measurements are very helpful in the derivation of 3D coseismic displacement fields as it provides more accurate displacement estimation in the north–south direction. 相似文献
987.
988.
农村信息化空间作用的影响因素与影响机理 总被引:1,自引:0,他引:1
选取中国农村产业结构构成、居民收入状况与受教育程度为解释变量,选取农村信息化水平为被解释变量,利用相关分析与回归分析相结合的方法,测定各种因素对农村信息化空间作用的影响强度。结果表明:信息化在农村地区的影响程度与当地农村居民的受教育程度、农村地区的产业结构、农村居民收入状况等因素关系密切;农村家用电脑拥有量与农村居民受教育程度之间关系最紧密,而固定电话和移动电话的拥有量与农村居民的收入水平关系紧密;要实现信息化对农村地区经济和社会发展的推动,既要根据地区发展水平采用适宜的基础设施,又要注重农村居民自身教育水平的提升。 相似文献
989.
利用MM5(V3.6)模式对2003年6月低纬高原地区一次大暴雨过程进行了数值模拟和地形敏感性试验,从重力波的角度研究低纬高原地区MβCSs生命史较短这一地域特征形成的原因。分析表明,大气稳定层结利于重力波的产生和传播,重力波的传播导致MβCSs的能量向两侧快速频散,使得成熟的MβCSs主体强度减弱,两侧有新的MβCSs生成并发展,中心降水也迅速减弱。地形敏感性试验表明,低纬高原地形使得大气在不稳定能量积累以后很快释放触发强降水,大气随即转化为稳定层结,利于重力波的快速传播和MβCSs主体能量的迅速频散,使得低纬高原地区触发暴雨的MβCSs生命史较短,引发的降水具有突发性强、历时短的特征。 相似文献
990.