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51.
采用基于用传统方法获取的海上单分量地震资料, 估算出同一位置速度的垂直分量(伪速度), 再与单分量压力数据联合, 达到压制鬼波的目的。将稀疏约束的反卷积方法作为鬼波压制的关键环节, 使得在浅海环境下, 由海水表面引起的检波器端上、下行波干涉产生的陷波问题得到改善, 同时低频能量得到增强, 提高了数据的分辨率。该方法可用于海上单分量压力数据的再处理, 拓宽数据的频带范围。 相似文献
52.
N. Calvo 《Journal of Computational and Applied Mathematics》2011,235(5):1394-1411
In this paper we develop a set of numerical techniques for the simulation of the profile evolution of a valley glacier in the framework of isothermal shallow ice approximation models. The different mathematical formulations are given in terms of a highly nonlinear parabolic equation. A first nonlinearity comes from the free boundary problem associated with the unknown basal extension of the glacier region. This feature is treated using a fixed domain complementarity formulation which is solved numerically by a duality method. The nonlinear diffusive term is explicitly treated in the time marching scheme. A convection dominated problem arises, so a characteristic scheme is proposed for the time discretization, while piecewise linear finite elements are used for the spatial discretization. The presence of infinite slopes in polar regimes motivates an alternative formulation based on a prescribed flux boundary condition at the head of the glacier instead a homogeneous Dirichlet one. Finally, several numerical examples illustrate the performance of the proposed methods. 相似文献
53.
针对船用海水表层水温观测以人工观测为主的现状,基于跨平台的Modbus库Libmodbus的走航式海洋表层水温监测系统,通过在船舶一侧布放处于船舶吃水线范围的水温传感器来采集表层水温信息。采用RS485/Modbus协议实现多站多点联网,构成分布式系统,进行海水表层温度的自动采集。上位机基于Modbus-RTU协议,并添加循环冗余校验以保证其对水温传感器的远程控制和表层水温信息采集功能的可靠性、安全性。该系统不仅运行稳定,操作简单方便,还具有可移植性和可扩展性。实验结果表明,该系统可以稳定可靠地监测海洋表层水温,实现表层水温的随船在线测量。 相似文献
54.
55.
利用卫星云图资料,结合东海入海爆发性气旋的生成和发展先兆,对东海入海爆发性气旋的发生、发展和移动路径等要素的预报方法进行了分析,并建立了相应的预报系统。实际资料效果检验表明:该方法对东海入海爆发性气旋要素预报的准确度较高,所建系统使用方便、灵活,为东海入海爆发性气旋的预报提供了新思路和新方法。 相似文献
56.
57.
《Analytical letters》2012,45(8):1433-1455
Abstract A method was developed for separation and analysis of corrosion products formed on the surface of Cu-Ni alloys immersed in sea water polluted by sulphide ions. This method is based on the selective dissolution of oxidation compounds by suitable solvents dissolving the metal matrix only to a negligeable extent. The following solvents were used: 1) methanol to dissolve Na+, Cu2+, Ni2+ chlorides and sulphates; 2) glycine to dissolve bivalent metal compounds - Cu2+, Ni2+ oxides, sulphides, oxysulphates, oxychlorides and oxycarbonates; 3) ammonia solution to dissolve Cu+ compounds (i.e. Cu2O and CuCl); 4) potassium cyanide to dissolve CU+ sulphides. Reasonable agreement between chemical and X-Ray analysis results was observed only for copper compounds, since nickel and iron compounds could not tie observed by X-Ray diffraction. The results of Auger and chemical analyses better agree with each other, yet no Fe compounds could be detected. This is to be attributed to the non-homogeneous corrosion layer which notably contains Fe compounds in the innermost region at a depth where Auger spectroscopy is unable to detect them, whereas their detection is possible by chemical analysis, since it is a bulk analysis. 相似文献
58.
Zhengbin Zhang Liansheng Liu Hongbin Zhao Youjun Fu Fengyun Cheng Weihong Zhao 《中国科学B辑(英文版)》1997,40(4):353-364
A new method for the study of ternary surface complexes at liquid-solid interface, theE(%) -pH curve method, was proposed. Four types ofE(%)-pH curves, namely, phenomenon of left-right shifts of S-shaped curve, V-shaped curve, monodirection shift curve and X-shaped
curve, were discovered. Correspondingly, apart from type (I) ternary surface complex
and type (II) ternary surface complex
, a new type of ternary surface complex
was discovered.
Project supported by the National Natural Science Foundation of China and the Fund of Doctoral Degree’s Spot. 相似文献
59.
Yue Li Pei Li Kailin Yang Qian He Yue Wang Yuhua Sun Chunnian He Peigen Xiao 《Molecules (Basel, Switzerland)》2021,26(23)
Sea buckthorn berries are rich in bioactive compounds and can be used for medicine and food. The variety and drying method used have an important influence on quality. In this study, different sea buckthorn varieties from China were selected and dried with four common drying methods. The total phenolic content (TPC), total flavonoids content (TFC), contents of 12 phenolic compounds and antioxidant capacity in vitro were analyzed. The results showed that the TPC, TFC and antioxidant activity of two wild sea buckthorn berries were higher than those of three cultivated berries, and for the same varieties, measured chemical contents and antioxidant activity of the freeze-dried fruit were significantly higher than those obtained with three conventional drying methods. In addition, forty-one compounds in sea buckthorn berry were identified by UPLC-PDA-Q/TOF-MS, most of which were isorhamnetin derivatives. Multivariate statistical analysis revealed narcissin and isorhamnetin-3-O-glucoside varied significantly in sea buckthorn berries of different varieties and with different drying methods; they were potential quality markers. Strong correlations were found between TPC, gallic acid and antioxidant capacity (p < 0.05). The results revealed how components and antioxidant activity varied in different sea buckthorn, which provides a valuable reference for quality control and further development and utilization of sea buckthorn. 相似文献
60.
Dorota Najgebauer-Lejko Katarzyna Liszka Magorzata Tabaszewska Jacek Domagaa 《Molecules (Basel, Switzerland)》2021,26(8)
Elderberries, sea buckthorn, and sloe berries are fruits of wild-grown bushes, valued in folk medicine for their health-promoting properties but still rarely applied in food. The aim of the present study was to produce probiotic yoghurts with a 10% addition of sweetened purees prepared from elderberries (EPY), sea buckthorn (SBPY), and sloe berries (SPY) and to assess their chemical composition, acidity, content of polyphenols and anthocyanins, ferric reducing antioxidant power (FRAP) and antiradical power (ARP), level of starter microbiota, concentration of acetaldehyde and diacetyl, syneresis, instrumentally measured color and texture parameters, and sensory acceptance. The results were compared to those obtained for plain probiotic yoghurt (PPY) and the changes tracked during 1 month of cold storage at 2 week intervals. The addition of elderberry and sloe berries significantly increased the antioxidant capacity of probiotic yoghurts, probably due to a high content of polyphenols, especially anthocyanins. However, anthocyanins were more stable in the EPY when compared to the SPY. All yoghurt treatments were characterized by good sensory quality and viability of starter microorganisms, including probiotic strains during cold storage. Elderberries promoted the evolution of diacetyl in yoghurts during storage and, together with sloe berries, produced increased syneresis and the greatest changes in color profile compared to PPY. 相似文献