古汉山井田地下水同位素组成特征研究

根据古汉山井田地下水中~3H、D、~(18)O和~(13)C等资料,建立了该井田鉴别主要含水层地下水的同位素标志,并对冲积层水、奥陶纪石灰岩水和煤系薄层石灰岩水之间的关系,以及矿井充水条件,做出了判断,为今后矿井基建、采矿中判别突水来源,提供了依据。     

坡风热力不稳定条件的讨论

本文在文献^[1,2]的基础上,说明坡风是一种耗散结构,并对形成坡风的热力不稳定条件进行了初步讨论,给出了临界瑞利数Rc作为坡风热力不稳定的判据。     

滇西地区九种岩石的P波Q值

本文叙述了以波传播和谱振幅比法测得的滇西地区九种岩石在不同应力状态下(σ_1=σ_2=σ_3=σ)的衰减系数,P波速度及Q值。在σ≤90 MPa时,随压力增加,衰减系数减小,P波速度及Q值增大;在σ≥120 MPa以后,衰减系数、P波速度及Q值变化甚小。其中团山砂岩及砖窑村片麻岩Q值较低。     

珠江口海域主导光学因子的遥感分类及其变化特征

基于2014年5月和8月珠江口海域的现场和实验测量数据,分析了光学因子和生态参数的动态变化特征,并找出该海域的主导光学因子;基于模拟的MODIS数据,构建了水体组分特征波长处吸收系数的遥感反演模型,并结合MODIS卫星遥感影像,依据IOCCG规则对主导光学因子进行遥感分类,揭示了珠江口海域2014年逐月水体主导光学因子的动态变化特征。结果表明,珠江口海域水体以a_d、a_g以及两种共同主导类型为主,并且a_g、a_d两种光学因子主导类型所占比例最大,其次是a_g主导类型,a_d主导类型所占比例最小。同时发现a_d（442）、a_dg（442）均与无机悬浮物浓度有较好的正相关关系,说明CDOM和悬浮泥沙具有相似的来源和动力变化过程。     

Impact of the Three Gorges Dam on the spawning stock and natural reproduction of Chinese sturgeon in Changjiang River,China

Chinese sturgeon (Acipenser sinensis) is the flagship species of the Changjiang River. The migration route of this species is blocked by the first dam, the Gezhou Dam, and its reproduction is affected by the Three Gorges Dam (TGD), one of the largest dams in the world. We studied the impact of the impoundment of the Three Gorges Reservoir (TGR) since 2003 on the spawning stock and the natural reproduction of the Chinese sturgeon by using our monitoring data from 1997 to 2013. Results indicate that TGR impoundment has delayed the first spawning dates of the fish from middle-late October to late November, decreased the amount of spawning activities from twice to only once each year, and significantly reduced egg production. In particular, the fish did not demonstrate any spawning activities in 2013. Therefore, TGR impoundment significantly affects the natural reproduction of the fish downstream of the TGD. The spawning stock size of the fish is also predicted to further decrease in the future, which will lead to a risk of population extinction. Ecological regulations must be imposed on decreasing the water temperature to 20°C before mid-October and increasing water discharge downstream of the TGD in October to induce spawning of the Chinese sturgeon.     

Improvement of the zygote utilization and reduction of the seedling loss in the early stage of seedling production of <Emphasis Type="Italic">Sargassum thunbergii</Emphasis> (Fucales,Phaeophyta)

Artificial seedling production of Sargassum thunbergii is an effective way to relieve pressure on natural resources. In order to improve the utilization of zygotes and reduce the loss of seedlings, studies on the characteristic of the zygotes release, the development of rhizoids, the attachment of germlings, and the influence of jet washing were conducted. Results show that the percent of zygotes released was increased with time in the first 60 h. The capacity of germlings attached to the substratum was significantly increased, especially coincident with the time of the new rhizoids emerged and elongated. The detachment rate of germlings significantly decreased with the delay of starting time of jet washing or the reduction of jet washing velocity. However, the jet washing at any level applied in the experiment could cause considerable loss of germlings within the 20 days after the attachment. Our study provided some parameters to optimize the operation in the early stage of seedling production.     

Phenological study of <Emphasis Type="Italic">Sargassum thunbergii</Emphasis> (Fucales,Phaeophyta) in Lidao Bay,Rongcheng, China

We conducted a phenological evaluation of Sargassum thunbergii, a common algal species, along the coast of Lidao Bay, Rongcheng, China. The local S. thunbergii population entered a maturation period from early June to mid-August, when seawater temperature was 14.4 to 25.1°C. Our results suggest an increase in temperature and day length during this period initiated thalli maturation. Inhabitants of the low tidal zone had higher thalli length and biomass compared with those from the mid-and high tidal zones. We observed a switch in the length frequency distribution and contribution of length classes to biomass between the small (<20 cm) and long (20–79.9 cm) length classes at the time of thallus maturity. This suggests there is a trade-offbetween sexual reproduction and vegetative regeneration.     

喷射式局部反循环钻具结构参数数值模拟

喷射式局部反循环钻具的流场主要是由喷反元件的射吸效应形成。为增强喷反钻具的反循环效果,提高岩心采取率,对喷反元件的主要结构参数对反循环效果的影响规律进行了研究;采用正交试验设计方法,借助计算流体动力学CFD软件,对不同结构参数组合下喷反钻具的反循环效果指标进行了回归分析。研究结果表明,喷反装置6个结构参数对目标值的影响由大到小的顺序是:喷嘴直径D1、喷嘴个数N1、喷嘴倾斜角度θ1、承喷孔直径D2、承喷孔倾斜角度θ2、承喷孔个数N2;当冲洗液泵量为1.5kg/s(90L/min)时,喷嘴直径D1=8mm,喷嘴个数N1=8,喷嘴倾斜角度θ1=67°,承喷孔直径D2=8mm,承喷孔倾斜角度θ2=5°,承喷孔个数N2=4为最优参数组合。