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Selection and application of wavelet transform in high-frequency sequence stratigraphy analysis of coarse-grained sediment in rift basin

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Petroleum Science 2024年第5期21卷 3016-3028页

作者： Ling Li zhi-Zhang Wang Shun-De Yin Wei-fang Wang zhi-Chao Yu Wen-Tian fan zhi-Heng Zhang National Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing102249China College of Geosciences China University of Petroleum(Beijing)Beijing102249China Civil and Environmental Engineering Department University of WaterlooWaterlooONN2L5Z5Canada SINOPEC Petroleum Exploration and Production Research Institute Beijing101599China

Wavelet transformation is a widely used method in high-frequency sequence stratigraphic ***, the application is problematic since different wavelets always return the same sequence analysis results. To address this issue, we applied five commonly used wavelets to theoretical sequence models to document some application criteria. Five gradual scale-change sequence models were simplified from the glutenite succession deposition by gravity flows to form the fining-upwards cycle sequences(FUCS) and coarsening-upwards cycle sequences(CUCS). After conducting theoretical sequence model tests, the optimal wavelet(sym4) was selected and successfully used with actual data to identify the sequence boundaries. We also proposed a new method to optimize the scale of continuous wavelet transformation(CWT) for sequence boundary determination. We found that the balloon-like marks in scalograms of db4, sym4, and coif4 wavelet determine, respectively, the fourth-order sequence boundary, the thick succession sequence boundaries in FUCS, and the thick succession sequence in FUCS and CUCS. Comparing the sequence identification results shows that the asymmetric wavelets had an advantage in high-frequency sequence boundary determination and sedimentary cycle discrimination through the amplitude trend of the coefficient, in which the sym4 wavelet is the most effective. In conclusion, the asymmetry of wavelets is the first selection principle, of which asymmetric wavelets are more sensitive to sediment deposition by flood flows. The match of the wavelet between the sequence is the second selection principle, in which the correlation of time-frequency impacts the accuracy of sequence surface localization. However, the waveform of the wavelet is a visual and abstract parameter for sequence boundary detection. The appropriate wavelet for lacustrine sequence analysis is the asymmetric wavelet with a weak number of side lobes. The depositional flows, depositional process,and autogeni

关键词： Wavelet analysis High-resolution sequence Sedimentary cyclicity Asymmetric wavelets

Fully integrated low phase noise multi-band LC-tank voltage controlled oscillator with switched-capacitor resonator

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The Journal of China Universities of Posts and Telecommunications 2012年第6期19卷 118-122页

作者： LI Bin fan Xiang-ning WANG zhi-gong School of Information Science and Engineering Southeast University

This paper presents the design and implementation of a fully integrated low noise multi-band LC-tank voltage-controlled-oscillator （VCO）. Multi-band operation is achieved by using switched-capacitor resonator. Additional three-bit binary weighted capacitor array is also used to extend frequency tuning range in each band. To lower phase noise, two noise filters are added and a linear varactor is adopted. Implemented in a 0.18 ~tm complementary-metal- oxide-semiconductor （CMOS） process, the VCO achieves a frequency tuning range covering 2.26-2.48 GHz, 2.48- 2.78 GHz, 2.94-3.38 GHz, and 3.45-4.23 GHz while occupies a chip area of 0.52 mm2. With a 1.8 V power supply, it draws a current of 10.9 mA, 10.6 mA, 8.8 mA, and 6.2 mA from the lowest band to the highest band respectively. The measured phase noise is - 109-- 120 dBc/Hz and - 121-- 131 dBc/Hz at a 1 MHz and 2.5 MHz offset from the carrier, respectively.

关键词： VCO multi-band phase noise linear varactor CMOS

Synthesis,Mass Spectrometric Studies,and Biological Evaluation of 3,5-Dimethoxyhomophthalic Acid and Related Compounds

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Chemical Research in Chinese Universities 2007年第5期23卷 533-537页

作者： GHULAM Qadeer NASIM Hasan-rama fan zhi-jin Department of Chemistry Quaid-I-Azam University Islamabad 45320 Pakistan State Key Laboratory of Elemento-Organic Chemistry Tianjin Key Laboratory of Pesticide Science Nankai University Tianjin 300071 P. R. China

3,5-Dimethoxyhomophthalic acid was synthesized in four steps from 3,5-dimethoxycinnamic acid via a series of reactions including cyclization of 3-（3＇,5＇-dimethoxyphenyl）propionic acid to 5,7-dimethoxy-1-indanone and oxidative decomposition of methyl-2-hydroxy-2-[5,7-dimethyoxy-1-oxo-1H-inden-2（3H）-ylidene]acetate to 3,5-dimethoxyhomophthalic *** synthesized compounds were characterized by elemental analysis,IR,1H NMR,and *** biological evaluation experiments of 3,5-dimthoxyhomophthalic acid and the related synthesized compounds were also carried *** occurring biologically active isocoumarins were prepared in a single step by the condensation of the homophthalic acid with appropriate acid chlorides.

关键词： 3,5-Dimethoxyhomophthalic acid Naturally occurring isocoumarin Biological evaluation

A novel caged-prenylxanthone from Garcinia bracteata

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Chinese Chemical Letters 2010年第4期21卷 443-445页

作者： Na, zhi Hu, Hua Bin fan, Qing Fei Chinese Acad Sci Xishuangbanna Trop Bot Garden Mengla 666303 Peoples R China

A novel caged-prenylxanthone xanthone,neobractatin(1),was isolated from the twig of Garcinia *** structure was elucidated by spectroscopic methods,especially 2D NMR techniques.

关键词： Garcinia bracteata Caged-prenylxanthone Neobractatin

A novel frequency-dependent hysteresis model based on improved neural Turing machine

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Science China(Information Sciences) 2023年第1期66卷 330-331页

作者： Yinan WU Yongchun fanG zhi fan Cunhuan LIU Institute of Robotics and Automatic Information System College of Artificial IntelligenceNankai University Tianjin Key Laboratory of Intelligent Robotics Nankai University

Dear editor,The inherent hysteresis of a piezoelectric actuator(PEA) results in intricate nonlinearity between the output displacement and input voltage, which restricts positioning accuracy of the actuator [1, 2]. Hysteresis behavior appears as a coupling of nonlinearity, frequency-dependence and memory characteristic, which makes it difficult to comprehensively characterize hysteresis [3]. To eliminate the effect of hysteresis on the positioning accuracy of PEAs,

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Foci of Future Studies on Abiotic Stress Tolerance of Maize in the Era of Post-Genomics

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Journal of Integrative Agriculture 2012年第8期11卷 1236-1244页

作者： LI You-zhi fan Xian-wei LIAO Jiang-xiong State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources Ministry of Science and Technology/Key Laboratory of Microbial and Plant Genetic Engineering Ministry of Education/College of Life Science and Technology Guangxi University Guangxi 530005 P.R. China Sugarcane Research Center Chinese Academy of Agriculture Sciences Guangxi 530007 P.R.China

Genetic and metabolic engineering approaches are powerful tools for improving the tolerance of maize to abiotic stresses because they are faster and can afford greater control over agronomically useful traits. However, in-depth understanding of the molecular mechanisms controlling response to abiotic stresses is the prerequisite for successful implementation of these strategies. A great flaw to dissect the biological mechanisms by genome sequencing is that genome sequencing approach could not reflect real-time molecular actions of plants especially under the stresses because the living organisms rarely live in unchanging environments. Post-genomics such as transcriptomics, metabolomics, and proteomics can generate knowledge that is closer to the biological processes. With the development of post-genomics, it can be expected that voluminous data will be generated. This paper proposes that future research on maize stress tolerance in the era of post-genomics should focus on metabolomics and proteomics; stress tolerance of whole plant rather than individual tissues or organs; coordination of expression of genes among tissues; characterization of promoters of stress-responsive genes; interrelation between mechanisms for tolerance to, and growth recovery from the stress; hexose metabolism as well as the glycolysis pathway; and foundation genotypes.

关键词： maize abiotic stresses research foci era of post-genomics

Stress corrosion cracking of X80 pipeline steel exposed to high pH solutions with different concentrations of bicarbonate

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International Journal of Minerals,Metallurgy and Materials 2013年第7期20卷 645-652页

作者： Lin fan Cui-wei Du zhi-yong Liu Xiao-gang Li School of Materials Science and Engineering University of Science and Technology Beijing

Susceptibilities to stress corrosion cracking （SCC） of X80 pipeline steel in high pH solutions with various concentrations of HC03 at a passive potential of-0.2 V vs. SCE were investigated by slow strain rate tensile （SSRT） test. The SCC mechanism and the effect of HC03 were discussed with the aid of electrochemical techniques. It is indicated that X80 steel shows enhunced susceptibility to SCC with the concentration of HCO3 increasing from 0.15 to 1.00 mol/L, and the susceptibility can be evaluated in terms of current density at -0.2 V vs. SCE. The SCC behavior is controlled by the dissolution-based mechanism in these circumstances. Increasing the concentration of HCO3 not only increases the risk of rupture of passive films but also promotes the anodic dissolution of crack tips. Besides, little susceptibility to SCC is found in dilute solution containing 0.05 mol/L HCO3 for X80 steel. This can be attributed to the inhibited repassivation of passive films, manifesting as a more intensive dissolution in the non-crack tip areas than at the crack tips.

关键词： pipeline steel stress corrosion cracking bicarbonate passive films

A construction of inter-group complementary codes with flexible ZCZ length

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第10期12卷 846-854页

作者： Li-fang FENG Xian-wei ZHOU Ping-zhi fan School of Information Engineering University of Science and Technology Beijing Beijing 100083 China Provincial Key Lab of Information Coding and Transmission Institute of Mobile Communications Southwest Jiaotong University Chengdu 610031 China

A general construction of inter-group complementary (IGC) codes is proposed based on perfect complementary (PC) codes,interleaving operation,and the orthogonal *** correlation properties of the newly constructed IGC codes can be described as follows:(1) the autocorrelation sidelobes of the codes are zeros in the zero correlation zone (ZCZ);(2) the cross-correlation functions (CCFs) between any two different codes of the same group are zeros in the ZCZ;(3) the CCFs between any two codes of different groups are zeros *** key point of this construction is that the ZCZ length of the generated IGC codes can be chosen *** is well known that there is a limitation between the ZCZ length and the number of mates;that is,the smaller is the length of ZCZ,the more are the IGC codes that can be ***,if we can choose the ZCZ length of the IGC codes flexibly according to the requirement of the system,more users can be accommodated in the system.

关键词： Z-complementary codes Perfect complementary codes Zero correlation zone

Characteristic signal extracted from a continuous time signal on the aspect of frequency domain

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Chinese Physics B 2019年第9期28卷 124-130页

作者： zhi-fan Du Rui-Hao Zhang Hong Chen College of Electronic Engineering Heilongjiang University

Extracting characteristic signal from a continuous signal can effectively reduce the difficulty of analyzing the running states of a single-variable nonlinear *** the extracted characteristic signal can accurately reflect the running states of the system is very *** this paper, a method called automatic sampling method(ASM) for extracting characteristic signals is *** complete definition is described, the effectiveness is proved theoretically, and the general formulas of the extracted characteristic signals are derived for the first ***, typical Chua's circuit is used to accomplish a lot of experimental research on the aspect of frequency *** experimental results show that ASM is feasible and practical, and can automatically generate a characteristic signal with the change of the original signal.

关键词： automatic sampling method characteristic signal frequency domain system states