日本以南黑潮流量对西北太平洋柔鱼渔场重心影响的滞后性分析

为研究西北太平洋海域黑潮流量对柔鱼Ommastrephes bartramii渔场的影响,本研究中结合1994—2010年西北太平洋海域黑潮流量和柔鱼渔场重心数据,采用阿尔蒙法建立了多项式分布滞后模型,通过分析黑潮流量异常与渔场重心偏移的互相关系数和模型的AIC值,确定了模型的最佳滞后期数,并添加了一阶滞后残差项以消除残差序列的自相关。结果表明:在经度方向上,黑潮流量异常在一年内对柔鱼渔场重心偏移没有明显的影响;而在纬度方向上,模型中黑潮流量异常变量的第12~15期系数均显著,分别为0.003 72(P<0.05)、0.004 93(P<0.01)、0.006 29(P<0.01)和0.007 81(P<0.05),说明黑潮流量异常会在6个月后的两个月内对渔场纬度重心产生正向的影响,模型调整后的相关系数为0.549。本研究中考虑了渔场对黑潮流量响应的时滞性,研究结果对延长西北太平洋柔鱼渔场预报的有效期限具有一定的参考意义。     

水温变化对秘鲁外海茎柔鱼栖息地的影响

为获取秘鲁外海茎柔鱼Dosidicus gigas栖息地的适宜温度指标,预测水温变化对茎柔鱼栖息地的影响,根据2006—2011年中国鱿钓船在秘鲁外海的茎柔鱼生产数据,并结合实测和通过卫星遥感技术获得的该海域海表温度数据,在作业次数和单位捕捞努力量渔获量(CPUE)基础上,采用海表温度适应性指数(Suitability index,SI)模型预测方法进行了相关研究。结果表明:随着水温的升高,茎柔鱼栖息地经向自西向东转移,纬向自北向南转移;产量较高的月份为7—12月,选取最佳适宜温度指标为19℃;发生厄尔尼诺现象时茎柔鱼产量下降,发生拉尼娜现象时产量则增加。     

中西太平洋人工集鱼装置禁渔期措施对中国大陆金枪鱼围网船队鲣产量特征的影响

为研究中西太平洋人工集鱼装置禁渔期措施对中国大陆金枪鱼围网船队鲣Katsuwonus pelamis产量特征的影响,通过收集2012—2015年中国大陆金枪鱼围网船队在中西太平洋的渔捞日志数据,对漂流人工集鱼装置(FADs)禁渔期和非禁渔期鲣的产量特征进行分析比较。结果表明:2012—2015年鲣产量占总渔获量的比例均超过80%,并没有发生明显波动;鲣渔获产量比例在2015年的非禁渔期出现明显的下降;2012年以后,鲣的平均单船产量和平均网次产量均明显下降,这可能与禁渔期的延长有关;K-S检验结果显示,2012—2015年,禁渔期与非禁渔期鲣的平均单船产量和平均网次产量均存在显著性差异(P<0.05);禁渔期结束后第一个月鲣的平均单船产量和平均网次产量均达到或接近全年最高水平。研究表明,中西太平洋海域FADs禁渔期的实施和延长会对中国大陆金枪鱼围网船队捕捞鲣造成一定程度的影响,业界需提高针对自由鱼群的捕捞效率,以适应日益严格的养护管理措施。     

负温条件下粉煤灰粒度分布对混凝土抗冻性的影响

针对我国三北地区冬季施工特点,研究了在不掺防冻剂的情况下,负温条件下粉煤灰粒度分布对混凝土抗冻性的影响。研究结果表明,随着养护时间增加早期不同粉煤灰粒度分布混凝土抗压强随着其细度的增加不断增加,后期抗压强度随着粉煤灰粒径变细而变化的幅度降低;质量损失率随着粉煤灰变细,出现先减小后增加的现象;相对动弹性模量随着粉煤灰粒度变细,会出现先增加后降低的现象。     

人工集鱼装置禁渔期措施对中国大陆金枪鱼围网船队捕捞努力量特征的影响

为探究人工集鱼装置(Fishing Aggregation Devices,FADs)禁渔期措施对中国大陆金枪鱼Thunnus thynnus围网船队捕捞努力量特征的影响,通过收集2012—2015年中国大陆金枪鱼围网船队在中西太平洋的渔捞日志数据,分别对中国船队在禁渔期和非禁渔期的捕捞努力量指标进行比较分析。结果表明:2012和2013年禁渔期和非禁渔期的平均投网时间存在显著性差异(P<0.05),而2014和2015年两者无显著性差异(P>0.05);禁渔期的作业时间利用率始终小于非禁渔期,但在研究期间两者差距逐渐减小;除2015年外,2012—2014年禁渔期的平均投网次数一直小于非禁渔期;禁渔期对自由鱼群的平均投网次数始终大于非禁渔期,且2015年差异最大。研究表明,中国船队可能正在通过主动调整捕捞努力量的投放策略以逐步适应FADs禁渔期措施带来的影响。     

“驻点”游人日时空分布对旅游 舒适度的影响——以网师园为例

中国景区旅游舒适度指标主要依据《景区最大承载量核定导则》推算,但此法无法呈现景区内部的游人舒适度差异。以网师园为例,运用驻点研究法,得到研究日各驻点停驻5s的总人次为128～1851,根据《导则》及网师园公布的舒适度指数,计算出其最大日承载量为5685人,人均空间承载指标为1.38m2/人。研究日游人入园总数为4376人,承载指标均未达上限,但各驻点实际停驻的总人次比按照《导则》计算出的承载量高出约10倍。计算各驻点游人分布密度与全园游人分布密度的比较系数K值,发现停驻时间为5、12、20s时,全天各驻点游人分布密度分别为全园平均游人密度的3.4～108.5、1.7～42.9和0.5～33倍(3个驻点K值1),说明驻点处游人会重复停驻,扩增效应明显,按《导则》推算旅游舒适度指数与实际情况差距较大。探索运用驻点研究法优化旅游舒适度指标的途径,为微景区旅游舒适度研究提供了新的视角。     

高产β-胡萝卜素杜氏藻突变株的鉴定与分析

采用紫外辐射诱导巴氏杜氏藻Dunaliellabardawil突变,经初筛和复筛,初步获得一株巴氏杜氏藻的突变株,对两者从细胞形态特征、β-胡萝卜素含量、蛋白质SDS-PAGE电泳以及总DNA的RAPD扩增等方面进行了比较分析。结果表明,在相同培养条件下,两者均为卵圆形,但原种直径仅为突变后藻株直径的60%,颜色差异明显;突变株的β-胡萝卜素含量为原种的6 2～15 5倍;两者遗传相似系数为0 868,与突变株的一般要求相符。鉴于此,确认其为高产β-胡萝卜素的新突变株,命名为Dunaliellabardawilvariant4-5Sun＆Liu。     

Effect of underground tunnel on the ground surface acceleration

A series of dynamic centrifuge tests was designed and conducted to study the seismic behavior of buried box tunnels. In this study, numerical simulations of the same tests were also performed using a finite difference software. The simulation results were in very good agreement with the results observed in the centrifuge tests. Subsequently, verified numerical model was used to perform parametric studies on the effect of an underground box tunnel on the ground surface acceleration. The results of parametric studies revealed that an underground tunnel could have either positive or negative effect on the ground surface acceleration. Presence of the tunnel amplifies long periods and deamplifies short periods of the motion. Therefore, it is concluded that the effect of an underground structure on the acceleration at the ground surface may be significant and hence, should be taken into account for seismic zonation of urban areas.     

Plutonium and 137Cs in surface water of the South Pacific Ocean

The present plutonium and 137Cs concentrations in South Pacific Ocean surface waters were determined. The water samples were collected in the South Pacific mid-latitude region (32.5 degrees S) during the BEAGLE expedition conducted in 2003-04 by JAMSTEC. 239,240Pu concentrations in surface seawater of the South Pacific were in the range of 0.5 to 4.1 mBq m(-3), whereas 137Cs concentrations ranged from 0.07 to 1.7 Bq m(-3). The observed 239,240Pu and 137Cs concentrations in the South Pacific were almost of the same level as those in the North Pacific subtropical gyre. The surface 239,240Pu in the South Pacific subtropical gyre showed larger spatial variations than 137Cs, as it may be affected by physical and biogeochemical processes. The 239,240Pu/137Cs activity ratios, which reflect biogeochemical processes in seawater, were generally smaller than that observed in global fallout, except for the most eastern station. The 239,240Pu/137Cs ratios in the South Pacific tend to be higher than that in the North Pacific. The relationships between anthropogenic radionuclides and oceanographic parameters such as salinity and nutrients were examined. The 137Cs concentrations in the western South Pacific (the Tasman Sea) and the eastern South Pacific were negatively correlated with the phosphate concentration, whereas there is no correlation between the 137Cs and nutrients concentrations in the South Pacific subtropical gyre. The mutual relationships between anthropogenic radionuclides and oceanographic parameters are important for better understanding of transport processes of anthropogenic radionuclides and their fate in the South Pacific.     

浅海空气声入水传播特性分析

结合射线和波数谱积分方法,对空气声入水传播途径进行了分析,利用海上试验数据进行了比较检验。结果表明,在浅海环境中,对水下声场有主要贡献的空气声入水传播途径,主要是透射穿过海面边界的折射直达声以及后续的海底反射声途径,其中折射直达声途径的贡献主要集中在声源正下方附近区域,当距离较远时,由于声线扩展损失效应以及直达声影区两方面的限制,折射直达声传播损失显著增加,对接收声场起主要贡献的是可以到达更远水平距离上的海底反射声,包括海底海面多次反射声。     

Analysis of selected herbicide metabolites in surface and ground water of the United States

One of the primary goals of the US Geological Survey (USGS) Laboratory in Lawrence, Kansas, is to develop analytical methods for the analysis of herbicide metabolites in surface and ground water that are vital to the study of herbicide fate and degradation pathways in the environment. Methods to measure metabolite concentrations from three major classes of herbicides--triazine, chloroacetanilide and phenyl-urea--have been developed. Methods for triazine metabolite detection cover nine compounds: six compounds are detected by gas chromatography/mass spectrometry; one is detected by high-performance liquid chromatography with diode-array detection; and eight are detected by liquid chromatography/mass spectrometry. Two metabolites of the chloroacetanilide herbicides--ethane sulfonic acid and oxanilic acid--are detected by high-performance liquid chromatography with diode-array detection and liquid chromatography/mass spectrometry. Alachlor ethane sulfonic acid also has been detected by solid-phase extraction and enzyme-linked immunosorbent assay. Six phenylurea metabolites are all detected by liquid chromatography/mass spectrometry; four of the six metabolites also are detected by gas chromatography/mass spectrometry. Additionally, surveys of herbicides and their metabolites in surface water, ground water, lakes, reservoirs, and rainfall have been conducted through the USGS laboratory in Lawrence. These surveys have been useful in determining herbicide and metabolite occurrence and temporal distribution and have shown that metabolites may be useful in evaluation of non-point-source contamination.     

黔北大方地区地下水及地表水化学类型及特征分析

结合贵州1:5万响水等6幅岩溶石山区域地质调查项目,对黔北大方地区不同地层区、不同类型的地下水及地表水采样分析,探讨其水化学特征。研究区有六种地表水化学成分类型、十种地下水化学成分类型类型主要为HCO_3~--SO_4~(2-)-Ca~(2+),HCO_3~--Ca~(2+),HCO_3~--Ca~(2+)-Mg~(2+)及HCO_3~--SO_4~(2-)-Ca~(2+)-Mg~(2+)四种类型;地表水及地下水的酸碱性均以弱碱性为主,占地表水的95.45%、占地下水的93.55%;矿化度及总固溶量均小于1000 mg/L,全为淡水;水的硬度以弱硬水为主,占地表水的68.18%,占地下水的58.06%;不同地层岩性区及不同水类型的水化学性质存在一定差异。     

工作温度和回水温度对水喷射泵性能的影响

比较了其他参数相同而流体工作温度和回水温度分别变化10℃时,二者对水喷射泵性能的影响.结果表明,回水温度变化对水喷射泵的截面比和性能影响较大,因此在供热系统运行中应尽量减小回水温度的波动.