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41.
浅水湖泊三角洲在中国许多陆相盆地中广泛发育,其中分流河道是三角洲平原最主要的砂体类型,它们大多呈现河道频繁改道、多级交叉及叠置的特点,往往形成极为复杂的地下储集层相互叠置的分布格局。基于松辽盆地浅水三角洲平原分流河道砂体的测井曲线特征,系统总结了浅水三角洲平原的分流河道河道类型与砂体叠置模式,并且分析了其对三角洲平原储集层砂体对比的约束作用。研究表明,分流河道河型可划分为3种基本类型:非典型辫流河型、非典型曲流河型和过渡型,其共同点是规模小、下切浅、分支快;而分流河道的叠置存在5种基本模式;河型与叠置特点决定了分流河道中泥质夹层分布存在2种基本类型,即平行分布式泥夹层与低角度侧积泥夹层。利用分流河道类型与叠置模式,可以分析河道发生变化的位置及井间砂体的连通情况,对储集层对比及连通关系分析具有约束作用。 相似文献
42.
43.
几种食用贝类淀粉酶活性的初步研究 总被引:2,自引:0,他引:2
本研究对10种常见食用贝类成体的淀粉酶在不同pH值、不同温度条件下进行了活性测定。结果表明,其总体消化器官淀粉酶的最适温度为:青蛤(Cyclina sinensis),33℃;缢蛏(Sinonovacula constricta),32℃;文蛤(Meretrix meretrix),43℃;等边浅蛤(Gomphina veneriformis),35℃;菲律宾蛤仔(Ruditapes philippinarum),34℃;泥螺(Bullacta exarata),40℃;彩虹明樱蛤(Moerella iridescens),37℃;微黄镰玉螺(Lunatica gilva),43℃;锈凹螺(Chlorostoma rusticum),43℃;疣荔枝螺(Thais clavigera),43℃;淀粉酶的最适pH值范围为4.6-4,9,不同贝类稍有不同;同一种类中肝脏淀粉酶的活性大于肠淀粉酶的活性。 相似文献
44.
Three surveys were carried out in Pearl River Estuary and adjacent coastal area in May, August, and November, 2013, to investigate the temporal and spatial variations of abundance of phycoerythrin-rich Synechococcus (PE-rich SYN) and phycocyanin-rich Synechococcus (PC-rich SYN). The effects of environmental factors on the alternation of the different Synechococcus groups were also elucidated. PE-rich SYN was detected in three surveys, whereas PC-rich SYN was detected in May and August, but not in November. The highest abundances of PE-rich SYN and PC-rich SYN were recorded in August and May, with mean values of 74.17×103 and 189.92×103 cells mL?1, respectively. From May to November, the relative abundance of PE-rich SYN increased, whereas that of PC-rich SYN declined. PE-rich and PC-rich SYN presented similar horizontal distributions with high abundance in the southern estuary in May, and in the western estuary in August. The abundances of PE-rich and PC-rich SYN were high at 27–32°C and salinity of 10–20. PC-rich SYN was not detected at < 24°C, and PC:PE-rich SYN decreased in abundance with salinity increase. When less than 20 mg L?1, suspended particulate matter (SPM) was helpful for Synechococcus growth. PE-rich SYN decreased in abundance when the concentration of dissolved inorganic nitrogen increased in May and November, and the concentration of phosphate increased in November. However, PC-rich SYN abundance and nutrients showed no correlation. Principal component analysis and regression analysis indicated that PE-rich SYN significantly correlated with the principal components that were affected by environmental factors. 相似文献
45.
在评估重力场模型计算空间扰动引力精度时,对模型截断误差常采用阶方差方法。文中将6种经典的重力异常阶方差模型与现有超高阶重力场模型的阶方差进行比较,TSD模型与重力场模型的差值最小。根据重力异常阶方差模型TSD,文中分析不同高度、不同阶次利用重力场模型计算空中扰动引力时截断误差的影响。实验结果表明:36阶模型截断误差最大径向和水平方向分别为26.455 1mGal、25.946 3mGal;360阶模型截断误差最大径向和水平方向分别为9.969 0mGal、9.960 9 mGal;2160阶模型截断误差最大径向和水平方向分别为2.538 5 mGal、2.538 1mGal;2160阶模型计算空中扰动引力时,即使在低空附近,截断误差在2.5mGal以内,计算高度超过5km,截断误差可以忽略;超过400km的高度,都可以用36阶模型计算,截断误差在1mGal以内。 相似文献
46.
Cen Jingyi Wang Jianyan Huang Lifen Lin Yarou Ding Guangmao Qi Yuzao Lü Songhui 《中国海洋湖沼学报》2021,39(1):242-258
Journal of Oceanology and Limnology - On May 24–29, 2019, a harmful algal bloom occurred in Pingtan coastal areas, Fujian, southeast China, and caused mass mortality of cage-cultured fish.... 相似文献
47.
M. Viel E. Branchini R. Cen J. P. Ostriker S. Matarrese P. Mazzotta B. Tully 《Monthly notices of the Royal Astronomical Society》2005,360(3):1110-1122
We present a simple method for tracing the spatial distribution and predicting the physical properties of the Warm–Hot Intergalactic Medium (WHIM), from the map of galaxy light in the Local Universe. Under the assumption that biasing is local and monotonic we map the ∼2 h −1 Mpc smoothed density field of galaxy light into the mass-density field, from which we infer the spatial distribution of the WHIM in the Local Supercluster. Taking into account the scatter in the WHIM density–temperature and density–metallicity relation, extracted from the z = 0 outputs of high-resolution and large-box-size hydrodynamical cosmological simulations, we are able to quantify the probability of detecting WHIM signatures in the form of absorption features in the X-ray spectra, along arbitrary directions in the sky. To illustrate the usefulness of this semi-analytical method we focus on the WHIM properties in the Virgo cluster region. 相似文献
48.
Patrick McDonald Uro Seljak Renyue Cen Paul Bode Jeremiah P. Ostriker 《Monthly notices of the Royal Astronomical Society》2005,360(4):1471-1482
We explore several physical effects on the power spectrum of the Lyα forest transmitted flux. The effects we investigate here are not usually part of hydrodynamic simulations and so need to be estimated separately. The most important effect is that of high column density absorbers with damping wings, which add power on large scales. We compute their effect using the observational constraints on their abundance as a function of column density. Ignoring their effect leads to an underestimation of the slope of the linear theory power spectrum. The second effect we investigate is that of fluctuations in the ionizing radiation field. For this purpose we use a very large high-resolution N -body simulation, which allows us to simulate both the fluctuations in the ionizing radiation and the small-scale Lyα forest within the same simulation. We find an enhancement of power on large scales for quasars and a suppression for galaxies. The strength of the effect rapidly increases with increasing redshift, allowing it to be uniquely identified in cases where it is significant. We develop templates that can be used to search for this effect as a function of quasar lifetime, quasar luminosity function and attenuation length. Finally, we explore the effects of galactic winds using hydrodynamic simulations. We find the wind effects on the Lyα forest power spectrum to be degenerate with parameters related to the temperature of the gas that are already marginalized over in cosmological fits. While more work is needed to conclusively exclude all possible systematic errors, our results suggest that, in the context of data analysis procedures, where parameters of the Lyα forest model are properly marginalized over, the flux power spectrum is a reliable tracer of cosmological information. 相似文献
49.
一种改进的频域相关法复图像快速配准 总被引:1,自引:0,他引:1
InSAR复图像配准是合成孔径雷达3维成像技术的一个关键步骤,要求达到亚像素级的配准精度.在分析了传统相关系数法的基础上,提出了改进的基于频域相关的快速配准算法.该方法分别采用频域相关和线性调频Z变换进行粗配准和精配准;最后利用傅里叶变换的平移性质对辅图像插值重采样.应用该算法对实际数据进行了实验,并从配准时间和精度两... 相似文献
50.
通过对某地勘单位资本运营现状的分析,探讨其财务指标在资本运营战略中的重要地位和作用,并根据目前该地勘单位在实行企业化管理中存在的资本流动洼差、存量资本不足、融资渠道单一、自有资本收益率不高、资金利用效率低等问题,提出了积极开展以财务为基础的金融资本运作和提早构建境外财务框架的建议。 相似文献