济南地区地下水位观测井固体潮对比研究

收集了济南地区3口地下水位观测井的水位观测数据,分析了水位资料的变化规律与差异,重点针对观测井的固体潮效应,采用维尼迪科夫调和分析法求解出各井孔固体潮效应参数值。对比分析了M2波月序列潮汐因子、相对误差的大小,对井孔的内在质量进行了对比分析及客观评价。     

Numerical study of an oscillating smaller cylinder in the wake of an upstream larger cylinder

A numerical study of flow around two tandem cylinders with unequal diameters was carried out. The upstream larger cylinder was fixed and the downstream smaller cylinder was allowed to oscillate in the transverse direction only. Comparisons of the experimental and numerical results were made to investigate the effects of the gap ratio on the maximum vibration amplitude and vortex shedding frequency. The results showed that the vibration response of the smaller cylinder was significantly affected by the presence of the upstream larger cylinder, and resulted in greatly reduced vibration amplitudes. With an increasing gap ratio, the vibration amplitude increased. However, the magnitude was lower than that corresponding to a single cylinder (with the same diameter as that of the downstream smaller cylinder) under the same flow conditions.     

Effect of nitrogen to phosphorus ratios on cell proliferation in marine micro algae

The ratio of nitrogen/phosphorus (N/P) is known to affect cell proliferation of some marine micro algae. We evaluated the effect of N/P ratios on the proliferation and succession of phytoplankton using five marine micro algae species. We used two sources of nitrogen, NH4Cl (N1) and urea (N2), and a single source of phosphorous, NaH2PO4(P). The optimal N/P ratio that differed among the five species was affected by the source of nitrogen, being as follows (N1/P, N2/P in order): Thalassiosira sp. (30/1, 20/1),...     

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Reproductive Biology of Yeilowfin Tuna T. albacares in the West-Central Indian Ocean

Survey of yellowfin tuna in the west-central Indian Ocean was conducted on board of Chinese Iongliners during 2003, 2004 and 2005, which is a part of Chinese Tuna Fishery Scientific Observer Program (CTFSOP). The reproductive biology has been investigated. A total of 1023 samples are collected including 417 ovaries and 606 testes. Spawning activities of yellowfin tuna have been studied for both male and female from January to June. The data showed that the average monthly sex ratio is 0.59, and the minimum length at sexual maturity is 101 cm for female and 110 cm for male respectively. Length at 50% sexual maturity is esti- mated at 113.77 cm for female and 120.20 cm for male, whereas maturation rate is 0.066 cm-1 for female and 0.091 cm-1 for male. Sex ratio by length class indicates that the proportion of male is higher than female's along with size increasing; for instance, in the group of the body length longer than 145 cm, some females have their body length from 145 to 160 cm and males have their body length at 160 cm and even longer. Statistically, yellowfin tuna has a significant seasonal reproduction.     

2017~2018年山东长岛震群双差波速比特征分析

通过限定震群集中区范围,剔除同一台站记录的震中位置相近且具有相同路径的地震波,使用双差波速比两次差分的方法,对2017~2018年长岛地区发生的2个震群的波速比值开展特征分析。通过对震相数据敏感性分析得出,双差波速比方法对Pg波到时较为敏感,资料处理时需要将Pg、Sg波震相误差分别控制在0.02 s和0.20 s以内。最终分析结果显示,长岛震群波速比值在1.69~1.78范围内波动,波速比变化与震群活动过程密切相关;震群几次较大余震发生前,波速比呈现低值状态;主震和余震的波速比变化存在差异,可能反映二者发震机理有所不同。     

基于试验与模型的根系增强抗剪强度分析

在总结近代学者对植物根系固土作用机制研究的基础上,采用大盒直剪试验与物理模型,对重庆缙云山地区6种常见植物:马尾松、香樟、广东山胡椒、四川大头茶、白毛新木姜子、四川山矾根系的增强抗剪强度进行对比。通过自制的大盒直剪仪对植物实际固土效果进行了测定,该大直剪仪具有简单、经济、易行等特点。通过对多种植物根系进行抗拉试验和根土复合体受力分析,确定了植物根系的抗拉强度与植物根面积比率。利用Wu模型对6种植物的根系固土效能进行模型计算。结果表明,不同的植物根系类型对增强抗剪强度值的影响非常显著。在重庆缙云山地区的土壤质地情况下,Wu的根土复合体模型高估了根系增强土壤的抗剪强度约为90%。基于该结论,为使Wu模型计算的根系固土强度值较为准确,修订Wu模型中的k值为0.63。     

Seismic velocity-ratio in the crust and uppermost mantle in southeast Wellington province,New Zealand

The regional variation of the seismic velocity-ratio () over a 200 km long traverse has been studied by means of microearthquake surveys. The Wadati-plot method is used with a minimum of four P and S arrivals for each of 49 earthquakes. The area as a whole is found to be characterized by a value of 1.74–1.76 for earthquakes of depth 12–40 km, except in a 50 km long section near Wellington, where is low at 1.60. This low has been attributed to the fault zones in the region. A small change of is observed between the upper crust (5 km) and lower crust (12 km), but there is no change of between the lower crust and uppermost mantle.     

Base cation concentrations in forest litter and topsoil have different responses to climate and tree species along elevational gradients

The forest litter is an essential reservoir of nutrients in forests, supplying a large part of absorbable base cations(BC) to topsoil, and facilitating plant growth within litter-soil system. To characterize elevational patterns of base cation concentrations in the forest litter and topsoil, and explore the effects of climate and tree species, we measured microclimate and collected the forest litter and topsoil(0-10 cm) samples across an elevational range of more than 2000 m(1243 ～ 3316 m a.s.l.),and analyzed the concentrations of BC in laboratory. Results showed that: 1) litter Ca concentration displayed a hump-shaped pattern along the elevational gradients, but litter K and Mg showed saddle-shaped patterns. Soil Ca concentration increased with elevation, while soil K and Mg had no significant changes. 2) Ca concentration in the forest litter under aspen(Populus davidiana) was significantly higher than that in all other species, but in topsoil, Ca concentration was higher under coniferous larch and fir(Larix chinensis and Abies fargesii). Litter K and Mg concentrations was higher under coniferous larch and fir, whereas there were nosignificant differences among tree species in the concentrations of K and Mg in topsoil. 3) Climatic factors including mean annual temperature(MAT), growing season precipitation(GSP) and non-growing season precipitation(NGSP) determined BC concentrations in the forest litter and topsoil. Soil C/N and C/P also influenced BC cycling between litter and soil. Observation along elevations within different tree species implies that above-ground tree species can redistribute below-ground cations, and this process is profoundly impacted by climate. Litter and soil Ca, K and Mg with different responses to environmental variables depend on their soluble capacity and mobile ability.     

高精度测量岩石样品Ce同位素组成的TIMS方法

介绍了对岩石样品的Ce同位素组成进行高精度测量的TIMS方法.采用α-羟基异丁酸(α-HIBA) 离子交换法分离和纯化岩石样品中的La、Ce元素, Ce同位素组成和La、Ce含量测定在Triton热电离质谱仪上完成.质谱标样JMC304的138Ce/142Ce比值统计值为0.0225762±0.0000015, 与大部分文献值一致.应用该方法对USGS玄武岩标样BCR-2和峨眉山玄武岩EQB的138Ce/142Ce比值和La、Ce含量进行了分析, 其结果分别为: 0.0225572±0.0000010、25.2±0.3μg/g、55.8±0.9μg/g和0.0225755±0.0000003、54.2±0.4μg/g、117.4±1.3μg/g.BCR-2的La、Ce含量测定结果与其证书值在误差范围内一致, 其分析精度为0.001%~0.005%.所有样品的140Ce/142Ce比值测定结果统计值为7.9439±0.0002, 介于文献最低值7.941与最高值7.947之间, 可能代表了该比值的最佳估计值.