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1.
采用新极谱技术(1.5次微分)的阳极溶出伏安滴定方法测定天然海水的铜络合容量和条件稳定常数。对测试条件、EDTA回收率和有关问题进行了探讨。青岛近岸水样的九次平行测定表明,铜的表现络合容量为3.01×10~(-7)mol/dm~3,条件稳定常数为7.34×10~7,相对标准偏差分别为9.2％和13.8％。 相似文献
2.
用自行设计安装的磁力浮沉子法密度装置测量溶液密度具有±3×10~(-3)kgm~(-3)的灵敏度,±3.5×10~(-3)kgm~(-3)的精密度。25℃时测定Nacl溶液的密度与Millero测量值平均偏差为2.6×10~(-3)kgm~(-3),求得NaCl的φ_v~0值为16.61(cm)~3mol~(-1)。 对12批中国标准海水及24个稀释中国标准海水的密度测量值(温度在15～25℃之间)与1980年国际海水状态方程计算值之间平均偏差为3.4×10~(-3)kgm~(-3)。实验结果表明中国标准海水及其稀释海水的密度与盐度及温度的关系遵从1980年国际海水状态方程。为中国标准海水作为溶液密度测量标准提供实验依据。 相似文献
3.
厦门西港和九龙江口悬浮颗粒中主要元素含量及其控制因素的研究 总被引：2，自引：0，他引：2
厦门西港和九龙江口春季(3月)表层海水TSM含量分别为17.80±6.16和60.11±75.25mg/dm~3,整个调查海区平均为38.96±56.50mg/dm~3。河流输入是河口区悬浮颗粒的主要来源。悬浮颗粒中Si,Al,Fe的含量最大(47.4～190×10~(-3),C,Ca,Mg,Ti,Mn的含量次之(平均在1.6～29.5×10~(-3)),其它元素的含量一般小于1×10~(-3)。因子分布表明:陆源输入、各种地球化学过程以及与生物活动有关的过程是控制悬浮颗粒化学组成的主要因素。 相似文献
4.
Ⅰ.硼的存在形式及去硼意义 据文献报道自来水中硼的含量为7×10~(-9)～0.2×10~(-6)g/L,海水中的含量为5×10~(-6)g/L,河水中的含量为13×10~(-6)g/L,地下水和卤水中的含量随各地而有所不同。在一般的水溶液中,硼以H_3BO_3,B(OH)_4~(-)形式存在,以H_3BO_3为主。硼酸是一元弱酸,是一种路 相似文献
5.
台湾海峡西部海域春季表观耗氧量的垂直分布及其极小值 总被引：1，自引：0，他引：1
根据1984年台湾海峡西部海域综合调查资料,分析了该海区春季表观耗氧量垂直分布的特征。结果表明,AOU垂直分布趋势为上低下高。表层均呈负值(-0.16×10~(-3)～-2.55×10~(-3)),底层1/2测站呈现负值(-0.04×10~(-3)～-2.42×10~(-3));而另1/2测站呈现正值(0～0.86×10~(-3))。AOU垂直分布有极小值的站位通常出现于不同水系的交汇带,其深度在密跃层下界附近。这是由于密跃层下界附近氧的涡动扩散进行得比热的涡动传导为慢的缘故。因而,逐渐增温时,氧来不及释放到大气中,即氧呈过饱和状态。浮游植物量对极小值的形成不起决定性作用,而只能影响极小值的大小。 相似文献
6.
采用牟氏角毛藻通过生物法测定青岛多处近岸水的铜络合容量CC_(cu)。此法测定的CC_(cu)值范围在1.6×10~(-7)～6.7×10~(-7)mol/dm~3之间。测定了4个经紫外线消解的海水中不同含量EDTA,结果表明,此法可较好反映水体中配位体的含量。使用1.5次微分ASV法也测定了这些样品的CC_(cu),两种方法测定结果比较,表明生物法测得的CC_(cu)值大于ASV法。这样差异可能与两种方法测定铜的形态不同有关。 相似文献
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厦门西港表层沉积物磷的形态与分布 总被引：5，自引：0，他引：5
本文简要地介绍了厦门西港表层沉积物中各形态的磷:总磷(TP)、有机磷(OP)、无机磷(IP)、水可溶解磷[P(sol)]、铁铝结合态磷[P(Al+Fe)]和钙结合态磷[P(Ca)]的含量与分布。结果表明,沉积物中TP的质量分数为(473～738)×10~(-6),平均值为560×10~(-6);TP中主要是IP,IP/TP值为60%,其他形态磷与总磷的比值是:P(sol)为1.5%,P(Al+Fe)为14%,P(Ca)为45%,OP为40%。 相似文献
9.
自1986年起,人们已在西太平洋弧后扩张中心发现多处热液成因硫化物矿床。主要分布在拉乌海盆、北斐济海盆、马纳斯海盆、马里亚纳海沟、冲绳海槽和伍德拉克海盆。其中拉乌海盆中Valu Fa海脊中金属硫化物中含金量高达29×10~(-6),平均为3×10~(-6)。样品分析表明,均属热液成因。这是首次在活动喷口区金属硫化物沉积中发现的含有原生金的样品。在冲绳海槽,大陆壳弧后裂谷和类黑矿型块状硫化物中含金量达14×10~(-6)。据最新报道,马纳斯海盆硫化物中金的平均含量为30×10~(-6),最 相似文献
10.
东山湾海水盐度,温度和溶解氧的分布特征 总被引：1，自引：0，他引：1
1988年5月、8月、11月和1989年2月东山湾海水的盐度范围分别为20.81～33.89、30.43～34.24、26.76～30.59和30.27～31.57;水温范围分别为23.4～25.0、22.5～30.8、18.1～20.7和14.5～17.3℃;溶解氧体积分数分别为(4.12～4.91)×10~(-3)、(3.50～5.10)×10~(-3)、(5.21～6.68)×10~(-3)和(5.64～6.00)×10~(-3);氧饱和度分别为85.1%～104%、73.3%～116%、99.6%～124%和102%～104%。春、夏季东山湾受高盐外海水的影响明显,其中夏季可能还受到上升流的影响.秋季浮游植物大量生长和繁殖,成为溶解氧含量和氧饱和度的主要影响因素。 相似文献
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并矢相关谱分析方法在非线性资料分析中的应用 总被引：2，自引：0，他引：2
本文利用到率并矢相关谱估计方法,对青岛月平均气温（1896年1月—1992年12月）足赤道局部地区日表层水温（0°±0．5°S,165°±0．5°E;1986年12月6日—1991年11月16日）进行了谱分析,结果表明：青岛气温除具有1年周期的主频振荡和二倍峰频处0．5年周期二阶非线性耦合效应外,还隐含有2年周期的低频耦合振荡及0．4年周期的高频耦合振荡;赤道局部地区日表层水温含有90天,63天,50天,40天和29天等几个主要的低频周期振荡。 相似文献
13.
Sampling effort required to recover the main gradients in marine benthic species composition 
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下载免费PDF全文 Marine benthic surveys and monitoring programs may have several goals. When the aim of such studies is to reveal and describe gradients in species composition, the gain in ecological insight achieved by the study depends on how well the spatial variability of species’ occurrence and abundance within the study area is covered by the sampling design. The common practice in such programs is to collect four or five grab samples from each visited site to capture the site's species composition. The rationale for this practice is based on the aim of capturing a large proportion of species at a specific site (i.e. point). We argue that this practice has been established without taking Iterative approaches into account, such as decreasing the sampling effort at each site and instead increase the number of sites visited. The collection and processing of data from marine sediment ecosystems are time‐consuming and, thus, expensive. Therefore, finding the optimal trade‐off between the number of sites visited and the number of samples per site is important. We examined this trade‐off by exploring how reduction of sampling effort per site affects the stability and recovery of gradients in species composition of marine benthic macrofauna. Our full data set consisted of four grab samples from each of 28 sites from the inner part of the Oslofjord, SE Norway. Procrustes analysis and calculation of Kendall's rank correlation coefficients showed that the main gradient in species composition extracted by detrended correspondence analysis of data sets with reduced per‐site sampling effort closely resembled the main gradient extracted for the full data set. Our results therefore suggest that marine benthic surveys that aim to identify the main gradient structure of species composition and relate this structure to main environmental complex gradients are likely to benefit from reducing the sampling effort at each site and, instead, increasing the number of visited sites. We argue that coverage of both the variation in species composition and the environment in the study area will then be improved. Monitoring programs with other aims than to identify the main gradients in species composition may also benefit from the adoption of a many‐sites, one‐sample sampling strategy. This may be particularly true if additional sampled sites are based on a stratified sampling strategy that ensures that the spatial variability in the study area is accounted for. 相似文献
14.
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15.
Air temperature is a key index reflecting climate change. Air temperature extremes are very important because they strongly influence the natural environment and societal activities. The Arctic air temperature extremes north of 60°N are investigated in the winter. Daily data from 238 stations at north of 60°N from the global summary of the day for the period 1979–2015 are used to study the trends of cold days, cold nights, warm days and warm nights during the wintertime. The results show a decreasing trend of cold days and nights(rate of –0.2 to –0.3 d/a) and an increasing trend of warm days and nights(rate of +0.2 to +0.3 d/a) in the Arctic. The mean temperature increases,which contributes to the increasing(decreasing) occurrence of warm(cold) days and nights. On the other hand,the variance at most stations decreased, leading to a reduced number of cold events. A positive AO(Arctic Oscillation) index leads to an increased(decreased) number of warm(cold) days and nights over northern Europe and western Russia and an increased(decreased) number of cold(warm) days and nights over the Bering Strait and Greenland. The lower extent of Arctic autumn sea ice leads to a decreased number of cold days and nights.The occurrences of abrupt changes are detected using the Mann-Kendall method for cold nights occurring in Canada in 1998 and for warm nights occurring in northwestern Eurasia in 1988. This abrupt change mainly resulted from the mean warming induced by south winds and an increased North Atlantic sea surface temperature. 相似文献
16.
采用3种多元分析方法,对来源于美国的4个凡纳滨对虾种群的13个形态比例参数进行比较研究.聚类分析结果表明,Kona Bay种群与Molokai种群形态差异很小,而SIS种群、OI种群趋异程度逐渐增加.判别分析结果显示,4种群的13个形态比例参数有着极显著的差异(P>0.01);4个种群雌虾的判别准确率P1为61.76%-97.14%,判别准确率P2为62.03%-96.43%,综合判别率为80.25%;4个种群雄虾的判别准确率P1为75.76%-97.06%,判别准确率P2分别为67.57%-97.06%,综合判别率为80.71%,各种群的判别函数判别准确率均较高;主成分分析,构建的雌体的5个主成分方差贡献率分别为,主成分1:23.594%,主成分2:19.534%,主成分3:15.748%,主成分4:13.653%,主成分5:8.653%.累积贡献率为81.182%.而在构建的雄体的5个主成分中,方差贡献率分别为主成分1:22.095%,主成分2:19.270%,主成分3:15.430%,主成分4:15.245%,主成分5:7.885%.累积贡献率为79.925%.综上所述,Kona Bay种群与Molokai种群应是同一种群,与SIS种群亲缘关系较为接近,SIS种群和OI种群为独立的种群. 相似文献
17.
The occurrence of gas hydrate has been inferred from the presence of Bottom-Simulating Reflectors (BSRs) along the western
continental margin of India. In this paper, we assess the spatial and vertical distribution of gas hydrates by analyzing the
interval velocities and Amplitude Versus Offset (AVO) responses obtained from multi-channel seismics (MCSs). The hydrate cements
the grains of the host sediment, thereby increasing its velocity, whereas the free gas below the base of hydrate stability
zone decreases the interval velocity. Conventionally, velocities are obtained from the semblance analysis on the Common Mid-Point
(CMP) gathers. Here, we used wave-equation datuming to remove the effect of the water column before the velocity analysis.
We show that the interval velocities obtained in this fashion are more stable than those computed from the conventional semblance
analysis. The initial velocity model thus obtained is updated using the tomographic velocity analysis to account for lateral
heterogeneity. The resultant interval velocity model shows large lateral velocity variations in the hydrate layer and some
low velocity zones associated with free gas at the location of structural traps. The reflection from the base of the gas layer
is also visible in the stacked seismic data. Vertical variation in hydrate distribution is assessed by analyzing the AVO response
at selected locations. AVO analysis is carried out after applying true amplitude processing. The average amplitudes of BSRs
are almost constant with offset, suggesting a fluid expulsion model for hydrate formation. In such a model, the hydrate concentrations
are gradational with maxima occurring at the base of hydrate stability zone. 相似文献
18.
高明君 《中国海洋大学学报(自然科学版)》1994,(2)
根据基因在异源多倍体染色体组间的变异，提出通过缺对一四体和双端体的酶谱分析，无需在不同品种间杂交，即可将同工酶结构基因定位在特定的染色体臂上。还提出，由于等位基因在双体和三体间的变异．通过三体酶谱分析，也能有效地进行同工酶基因定位。 相似文献
19.
In this paper, an approximate closed-form solution is presented to compute the moisture-related buckling of symmetric angle-ply laminates. The environment corresponds to a steady state condition, which provides a uniform moisture distribution for the laminate. The laminate consists of four layers [θ/−θ]s constructed of low, moderate and high stiffness ratio materials. Comparative results using the Rayleigh–Ritz method provides a means of assessing the accuracy of the expression. For certain laminate architectures, several modes must be computed to ascertain the lowest buckling mode, and once identified, provides an excellent approximation for the mode computed using the Rayleigh–Ritz method. 相似文献
20.
自20世纪80年代以来,我国出台了众多海洋捕捞相关政策,厘清这些政策变迁规律对海洋捕捞业的健康发展具有重要意义。本文对1986年以来我国海洋捕捞业的政策文本展开量化分析,构建政策时间维度、政策工具维度、政策价值维度三维政策文本分析框架,梳理当前捕捞业政策变迁和结构特征,并深入分析了捕捞业政策与现实的匹配性。研究发现,海洋捕捞业的部分政策目标之间存在一定的冲突和矛盾;政策工具体系全面,但不同政策工具数量分布不均衡;早期政策的经济价值取向突出,社会、生态价值相对不足,需要适时调整政策价值取向。未来应明确政策目标,推动海洋捕捞管理范式由投入控制向产出控制的转变;优化政策工具组合,引导渔民自觉养护海洋渔业资源,提高海洋捕捞业政策的有效性;整合政策价值取向,协调产业发展、资源养护和渔民利益的关系,推动海洋捕捞可持续发展。 相似文献