“陆态网络”Ⅱ期西部绝对重力测定结果分析     

何志堂  韩宇飞  康胜军  王晓栋  赵丕  任敏拴 《大地测量与地球动力学》2015,35(6):927-930

介绍了2013~2014中国大陆构造环境监测网络的基本情况及西部地区绝对重力观测的情况,并对观测结果进行分析。结果表明,成果稳定性良好,89.5%的成果观测精度优于±5.00μGal,能够满足"陆态网络"的技术要求。  相似文献   

Reproduction in the intertidal limpet Cellana ornata in southern New Zealand     

R. A. Dunmore  D. R. Schiel 《新西兰海洋与淡水研究杂志》2013,47(4):653-660

The reproductive cycle of the abundant intertidal limpet Cellana ornata (Dillwyn 1817) was examined over 19 months, covering two breeding periods, on a rocky intertidal platform in southern New Zealand. A gonad index was calculated, and histological sections were used to count the numbers of mature and immature eggs present. Fecundity was estimated using counts of eggs before and after spawning. To determine any variation between sites, the gonad index of limpets at a second site dominated by boulders was examined over 6 months during the second breeding period. C. ornata had a single spawning period annually during summer, with greatest gonad sizes in January‐February. There were significant differences in peak gonad indices between two breeding seasons on the platform. Within the second breeding period, both the timing and magnitude of peak gonad development differed between sites, with lower reproductive output at the boulder site. Fecundity increased with increasing size, but individuals are probably capable of reproducing after their first year on the shore. The life history of this species is discussed in comparison to other limpets in New Zealand.  相似文献   

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陈钊  李辉  邢乐林  孙少安  张晓彤  张品 《大地测量与地球动力学》2014,34(2):27-30

???????????????????????????????????????????????????80 cm??130 cm??????????????????????仯??????0.02×10^-8 ms^-2/cm??????????仯????仯??????????????????????FG5??A10???????????????????????????????????????????????????仯????????  相似文献   

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����Ӣ  �¹�  ������  ��־��  ����� 《大地测量与地球动力学》2014,34(6):114-118

??????????????(BDS)???????????????????????????и???????????????????????????????????????????????t??????????????????????????????????BDS??????????????????????????????????????????t??????????????????????cm/s?????????????λ???????????????????????????mm/s???????????????У????????????????????????豸????????????????cm/s??????????????????????????????豸????????????????dm/s????????????????????????????????????????  相似文献   

Effects of the oophagous bivalve Acesta oophaga on the morphology and fecundity of its deep‐sea tubeworm host,Lamellibrachia luymesi     

Zair P. Burris  Joshua P. Lord  Craig M. Young 《Marine Ecology》2014,35(1):106-111

The deep‐sea bivalve Acesta oophaga lives attached to the anterior end of the vestimentiferan tubeworm, Lamellibrachia luymesi, at cold methane seeps. The bivalve is found almost exclusively on female tubeworms, where it consumes the lipid‐rich eggs of L. luymesi that are spawned year round (Biological Bulletin, 209, 2005, 87). It is apparent that A. oophaga benefits directly from this close association, but the consequences for the tubeworm host may be more complicated than just a simple predator–prey interaction. Since A. oophaga completely surrounds the tube opening and plume of the worm, it is likely that its presence would limit oxygen uptake by L. luymesi, thereby inhibiting worm growth and reproduction. We hypothesized that occupied tubeworms would compensate for this by growing larger plumes for oxygen uptake. To explore the effects of bivalve presence/absence on female tubeworms, several morphological features, including body size, plume length, tube diameter, and tube segment length, as well as instantaneous fecundity, were compared. Results suggest that the mere presence of A. oophaga has a significant impact on the morphology of its host worm, as all measures of worm size, except for tube segment length, were significantly greater with clams present. Additionally, instantaneous fecundity was 3.5 times higher in occupied worms, implying that tubeworms are not oxygen‐deprived or energy limited as a result of bivalve presence. Our findings suggest that the association between these two deep‐sea organisms may be a more complex form of symbiosis than the simple predator–prey relationship, as previously thought.  相似文献   

基于加速器控制网的GPS绝对测量精度探讨     

马娜  董岚  梁静  向伟  罗涛  王铜  刘璨  柯志勇  何振强 《北京测绘》2014,(6):23-27

针对当前散裂中子源准直测量控制网空间距离大、绝对精度要求高,常规测量难以满足需要的问题,提出采用不受通视限制、高精度的GPS测量解决,通过GPS在“标准检测场”准直实验,计算分析后处理软件、观测仪器及观测时长对GPS绝对测量精度的影响,结果表明,1km的测区范围,商业软件解算结果优于科研软件,且商业软件中TTC解算精度最高;分体机比一体机观测精度更高,但随观测时长增长,二者精度相当;观测时长超过8小时以上,基线值将趋于稳定。  相似文献   

香山绝对点周围的局部地壳变形及其对重力测量结果的影响   总被引：1，自引：0，他引：1  

刘少明  高荣胜  贾民育 《大地测量与地球动力学》2002,22(2):97-100

为了监视北京地区的地壳稳定性，北京测绘院对10多个基岩点和北京市区进行了多次沉降观测，结果表明香山点近10多年来高程变化只有几毫米，其重力效应可略而不计，但测点东北和东南方有两个较大的下沉区。用线积分法计算了两个局部沉降的重力效应，在沉降区中心其影响可达0.38μms^-2，但对香山点的重力效应非常小，完全可以忽略。因此得出如下结论：香山点观测到的重力变化不是地壳变形引起的。  相似文献   

采用弱基准和抗差估计的重力网平差     

赵德军  张敏利  王强  陈永祥 《测绘工程》2015,(1):25-27,32

以沿海某测区绝对重力和相对重力网数据处理为例,详细描述了弱基准重力网平差的方法,绝对重力和相对重力先验权的确定,用抗差等价权来调整相对重力的权、重力仪参数的取舍。结果表明,弱基准能有效地提高整网的精度;抗差估计能有效地探测并降低异常数据的权。重力点平均中误差为13.6×10-8 ms-2,偶然误差检验符合正态分布。  相似文献   

疏散星团NGC2244天区恒星的绝对自行研究     

GAO Jianyun CHEN Li WANG Jiaji 《中国科学院上海天文台年刊》2005,(1):60-78

利用上海天文台相隔35年的两期照相底片资料,测定了疏散星团NGC2244所在天区55’×55’范围内495颗恒星基于Tycho-2星表的位置和绝对自行,并对自行精度作了初步分析。  相似文献   

中国-日本绝对重力仪器测量比对结果   总被引：3，自引：0，他引：3  

孙和平  张为民  王勇  竹本修三  福田洋一 《测绘科学》2006,31(6):33-34,51

本文给出了中科院测地所FG5-112和日本京都大学FG5-201及日本国土地理院FG5-104等几台绝对重力仪在武汉九峰和香港天文台绝对重力测量比对结果。分析说明不同仪器间具有良好的一致性,其中FG5-112与FG5-104结果间的互差达8×10-8m/s2;FG5-112与FG5-201和FG5-104等的观测互差小于2×10-8m/s2。这种比对观测,可为深入了解仪器性能和精确测定不同台站重力非潮汐变化提供可靠参考。  相似文献