Identification of a chitinase from the hepatopancreas of Chinese black sleeper(Bostrychus sinensis)     

Yulei Chen  Zhipeng Tao  Minghui Zhang  Lechang Sun  Guangming Liu  Minjie Cao 《海洋学报(英文版)》2021,40(6):50-60

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Experimental characterization,design and modelling of the RBRL seismic‐isolation system for lightweight structures          下载免费PDF全文

Marco Donà  Alan Hugh Muhr  Giovanni Tecchio  Francesca da Porto 《地震工程与结构动力学》2017,46(5):831-853

The Rolling‐Ball Rubber‐Layer (RBRL) system was developed to enable seismic isolation of lightweight structures, such as special equipment or works of art, and is very versatile, a great range of equivalent natural frequencies and coefficients of damping being achievable through choice of the system parameters. The necessity to have a simple and effective design procedure has led to a new parametric experimentation at Tun Abdul Razak Research Centre (TARRC) on the rolling behaviour of the RBRL system and load–deflection behaviour of the recentering springs. The experimental results, together with theories for the rolling resistance of a loaded steel ball on a thin rubber layer and the lateral load–deflection behaviour of cylindrical rubber springs, are used to develop a general design method for the RBRL system, which allows the system to be tailored to the specific application. Sinusoidal test results are presented for the small‐deflection behaviour of the system, influenced by the presence of a viscoelastic depression on the rubber tracks beneath each ball, and an amplitude‐dependent time‐domain model is proposed, based on these results and on the steady‐state behaviour of the system. The model is validated through comparison with previously performed shaking‐table tests. Attention is here restricted to uniaxial behaviour. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

地震反Q滤波应用于碳酸盐岩储层特征描述          下载免费PDF全文

周衍  饶莹 《地球物理学报》2018,61(1):284-292

塔里木盆地塔河地区的奥陶系碳酸盐岩储层埋藏深,其深度超过5000 m,储集体类型以裂缝、缝洞为主,储层的纵向和横向上都具有极强的非均质性.这些特点导致反射地震数据的信噪比低、分辨率低,从而使得碳酸盐岩储层特征描述的难度增大.针对这些问题,本文运用稳定化反Q滤波方法对塔河地区的三维地震数据进行提高分辨率处理,同步实现地震振幅补偿和子波相位校正.处理结果与原始地震数据进行地震剖面面貌、储层内幕信息、断裂缝洞刻画等方面的直接对比,一方面展示反Q滤波方法在提高分辨率、提高弱反射能量、以及增强反射同相轴的空间连续性等方面的优势,同时展示稳定化反Q滤波方法能够提高对奥陶系碳酸盐岩缝洞储集体的特征描述精度.  相似文献   

Rock physics model for seismic velocity & fluid substitution in sub-resolution interbedded sand–shale sequences     

Nishank Saxena  Ronny Hofmann  Seán Dolan  Rituparna Sarker  Chen Bao  Stephan Gelinsky 《Geophysical Prospecting》2019,67(4):843-871

The measured geophysical response of sand – shale sequences is an average over multiple layers when the tool resolution (seismic or well log) is coarser than the scale of sand – shale mixing. Shale can be found within sand – shale sequences as laminations, dispersed in sand pores, as well as load bearing clasts. We present a rock physics framework to model seismic/sonic properties of sub-resolution interbedded shaly sands using the so-called solid and mineral substitution models. This modelling approach stays consistent with the conceptual model of the Thomas–Stieber approach for estimating volumetric properties of shaly sands; thus, this work connects established well log data-based petrophysical workflows with quantitative interpretation of seismic data for modelling hydrocarbon signature in sand – shale sequences. We present applications of the new model to infer thickness of sand – shale lamination (i.e., net to gross) and other volumetric properties using seismic data. Another application of the new approach is fluid substitution in sub-resolution interbedded sand–shale sequences that operate directly at the measurement scale without the need to downscale; such a procedure has many practical advantages over the approach of “first-downscale-and-then-upscale” as it is not very sensitive to errors in estimated sand fraction and end member sand/shale properties and remains stable at small sand/shale fractions.  相似文献   

Integrating facies-based Bayesian inversion and supervised machine learning for petro-facies characterization in the Snadd Formation of the Goliat Field,south-western Barents Sea     

Honoré Yenwongfai  Nazmul Haque Mondol  Isabelle Lecomte  Jan Inge Faleide  Johan Leutscher 《Geophysical Prospecting》2019,67(4):1020-1039

Seismic petro-facies characterization in low net-to-gross reservoirs with poor reservoir properties such as the Snadd Formation in the Goliat field requires a multidisciplinary approach. This is especially important when the elastic properties of the desired petro-facies significantly overlap. Pore fluid corrected endmember sand and shale depth trends have been used to generate stochastic forward models for different lithology and fluid combinations in order to assess the degree of separation of different petro-facies. Subsequently, a spectral decomposition and blending of selected frequency volumes reveal some seismic fluvial geomorphological features. We then jointly inverted for impedance and facies within a Bayesian framework using facies-dependent rock physics depth trends as input. The results from the inversion are then integrated into a supervised machine learning neural network for effective porosity discrimination. Probability density functions derived from stochastic forward modelling of endmember depth trends show a decreasing seismic fluid discrimination with depth. Spectral decomposition and blending of selected frequencies reveal a dominant NNE trend compared to the regional SE–NW pro-gradational trend, and a local E–W trend potentially related to fault activity at branches of the Troms-Finnmark Fault Complex. The facies-based inversion captures the main reservoir facies within the limits of the seismic bandwidth. Meanwhile the effective porosity predictions from the multilayer feed forward neural network are consistent with the inverted facies model, and can be used to qualitatively highlight the cleanest regions within the inverted facies model. A combination of facies-based inversion and neural network improves the seismic reservoir delineation of the Snadd Formation in the Goliat Field.  相似文献   

A new energy density calculation method for reservoir delineation using seismic low-frequency signal     

Xin Luo  Xuehua Chen  Yingkai Qi  Jidong Yang  Jie Zhang  Wei Jiang 《Geophysical Prospecting》2020,68(8):2518-2535

In comparison to high-frequency signals, low-frequency seismic signals suffer less from scattering and intrinsic attenuation during wave propagation, penetrate deeper strata and thus can provide more energy information related to the hydrocarbon reservoirs. Based on the asymptotic representation for the frequency-dependent reflections in the fluid-saturated pore-elastic media, we first derive a novel equation of the reservoir energy density and present an efficient workflow to calculate the reservoir energy density using low-frequency seismic data. Then, within a low-frequency range (from 1 to 30 Hz), we construct an objective function to determine the optimal frequency, using the energy densities calculated from the post-stack seismic traces close to the wells. Next, we can calculate the reservoir energy density using the instantaneous spectra of optimal frequency at the low-frequency end of the seismic spectrum. Tests on examples for synthetic and field data demonstrate that the proposed reservoir energy density can produce high-quality images for the fluid-saturated reservoirs, and it produces less background artefacts caused by elastic layers. This method provides a new way to detect the location of hydrocarbon reservoirs and characterize their spatial distribution.  相似文献   

西印度洋产纤维素酶细菌的筛选及酶学特性初步研究          下载免费PDF全文

吴旭东  童凡  夏钰华  黄仕新  黄家琪  徐长安  唐旭 《应用海洋学学报》2024,43(1):183-191

本研究从西印度洋表层沉积物中筛选获得1株高抗性、稳定性好的纤维素酶高产菌株XN149,通过形态学、革兰氏染色、生理生化鉴定以及16S rRNA基因序列分析对菌株进行分类鉴定,并研究了其酶学特性。结果表明,菌株XN149为漳州芽孢杆菌（Bacillus zhangzhouensis）,具有较高的产纤维素酶能力。酶学特性研究表明,该菌株所产纤维素酶的最适反应温度为65 ℃,最佳pH为6.0,该条件下发酵48 h后粗酶液酶活力为（60.19±0.31） U/mL。在30～60 ℃及pH为5.0～8.0时酶活性稳定性较高,Fe3+、Mn2+对该酶活性有一定的促进作用,Ba2+对其酶活性具有抑制作用。综上,漳州芽孢杆菌XN149是一株高产纤维素酶菌株,所产纤维素酶具有良好的耐热性和一定的酸碱耐受性,具有潜在的产业应用开发价值。  相似文献   

动物蛋白酶解物与无机氮、磷源的组合对小球藻(Chlorella vulgaris)生长和生化指标的影响          下载免费PDF全文

叶林超  叶均安  徐国忠  刘建新 《海洋与湖沼》2009,40(2):176-180

采用三因素不完全正交设计方法,通过对细胞密度、干重、叶绿素和可溶性蛋白质含量的测定.确定了N、P源与蛋白酶解物之间的最佳组合,研究碳酸氢铵作为N源、磷酸二氢钠作为P源与动物蛋白酶解物之间的组合对小球藻生长和生化指标的影响.结果表明:(1)动物蛋白酶解物与N、P源间存在互作效应--影响小球藻细胞密度、叶绿素的主要因素分别是P浓度、蛋白酶解物浓度;而N浓度及蛋白酶解物浓度同时对小球藻的蛋白质含量起主要作用;(2)同时添加N 50mg/L、P 4mg/L、蛋白酶解物12ml/L能显著提高小球藻生物量,促进叶绿素和藻体蛋白质的合成(P<0.05).  相似文献   

星载毫米波测云雷达资料的云特征分析   总被引：1，自引：0，他引：1  

严卫  杨汉乐  叶晶 《遥感学报》2009,13(4):575-584

基于CloudSat卫星资料, 综合地基和天基遥感资料云特征反演算法, 开展了云分类和云相态识别方法研究, 并将所得结果分别与CloudSat数据处理中心(DPC)发布的云分类产品和CALIPSO星上载荷Lidar产品进行了比对分析和个例研讨。  相似文献