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Implications for fault reactivation and seismicity induced by hydraulic fracturing

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Petroleum Science 2024年第2期21卷 1081-1098页

作者： zi-Han sun Ming-Guang Che Li-Hong Zhu Shu-Juan Zhang Ji-yuan Lu Chang-Yu Jin Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines School of Resources and Civil Engineering and Key Laboratory of Liaoning Province on Deep Engineering and Intelligent TechnologyNortheastern UniversityShenyang110819LiaoningChina Research Institute of Petroleum Exploration&Development PetroChina Company LimitedBeijing100084China The Exploration and Development Research Institute of Daqing Oilfield Limited Company Daqing163458HeilongjiangChina

Evaluating the physical mechanisms that link hydraulic fracturing(HF) operations to induced earthquakes and the anticipated form of the resulting events is significant in informing subsurface fluid injection operations. Current understanding supports the overriding role of the effective stress magnitude in triggering earthquakes, while the impact of change rate of effective stress has not been systematically addressed. In this work, a modified critical stiffness was brought up to investigate the likelihood, impact,and mitigation of induced seismicity during and after hydraulic fracturing by developing a poroelastic model based on rate-and-state fraction law and linear stability analysis. In the new criterion, the change rate of effective stress was considered a key variable to explore the evolution of this criterion and hence the likelihood of instability slip of fault. A coupled fluid flow-deformation model was used to represent the entire hydraulic fracturing process in COMSOL Multiphysics. The possibility of triggering an earthquake throughout the entire hydraulic fracturing process, from fracturing to cessation, was investigated considering different fault locations, orientations, and positions along the fault. The competition between the effects of the magnitude and change rate of effective stress was notable at each fracturing stage. The effective stress magnitude is a significant controlling factor during fracturing events, with the change rate dominating when fracturing is suddenly started or stopped. Instability dominates when the magnitude of the effective stress increases(constant injection at each fracturing stage) and the change rate of effective stress decreases(the injection process is suddenly stopped). Fracturing with a high injection rate, a fault adjacent to the hydraulic fracturing location and the position of the junction between the reservoir and fault are important to reduce the Coulomb failure stress(CFS) and enhance the critical stiffness as

关键词： Hydraulic fracturing Coulomb failure stress Rate-and-state fraction model Linear stability analysis Critical stiffness Seismically induced fault

Modulation of NRF2 and UGT1A expression by epigallocatechin-3-gallate in colon cancer cells and BALB/c mice

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Chinese Medical Journal 2009年第14期122卷 1660-1665页

作者： ZHANG Zhi-mian YANG Xiao-yun yuan Jun-hua sun zi-yuan LI Yan-qing Health Examination Center Department of Gastroenterology Qilu Hospital of Shandong University Jinan Shandong 250012 China Department of Digestive Disease Shandong Provincial Hospital Affiliated to Shandong University Jinan Shandong 250012 China Department of Breast Surgery the Affiliated Hospital of Shandong University of Traditional Chinese Medicine Jinan Shandong 250011 China

Background Green tea is an important source of flavonoids in human diets and epidemiological data correlate green tea consumption with a reduced cancer risk. Given its complicated properties at effective concentrations, we put epigallocatechin-3-gallate （EGCG） that previously reported on its anti-proliferative activities against several cancer cell lines on our research agenda to further examine the mechanism of its chemopreventive potential. Methods RNA interference （RNAi） expression vector pSilencer 3.1-H1 was used to construct recombinant nuclear factor erythroid 2 related factor 2 （Nrf2）-targeting RNAi plasmids. EGCG （5 μg/ml） was added into the culture fluid of cells before and after transfection. RT-PCR and Western blotting were used to detect the expression of uridine 5＇-diphosphate-glucuronosyltransferase （UGT）IA in cells. Forty male BALB/c mice were assigned to four groups： a normal unexposed control and three groups treated with varying doses of EGCG. Four weeks later, the mice were sacrificed, and their colon tissues were subjected to mRNA and protein expression of Nrf2 and UGT1A via RT-PCR and Western blotting analysis. Results EGCG up-regulated the expression of Nrf2 and increased the level of UGT1A in cells. The blockade of Nrf2 activity via RNA intervention largely attenuated the induction of UGT1A expression by EGCG. In mice, the mRNA and protein levels of Nrf2 and UGT1A detected by RT-PCR and Western blotting increased （both P 〈 0.05 compared with the control）. This increase in Nrf2 expression also had a positive correlation with an increased UGT1A expression. Conclusions EGCG mediated its effect in part by inducing the NRF2 signaling pathway and increasing UGT1A expression. Both in vitro and in vivo studies demonstrated the role of NRF2 and UGT1A expression in the potential use of EGCG as a possible chemopreventive agent and supported further study of EGCG for cancer treatment.

关键词： epigallocatechin-3-gallate colon UDP-glucuronosyltransferase 1A nuclear factor erythroid 2 related factor 2

A Fluorine-Functionalized 3D Covalent Organic Framework with Entangled 2D Layers

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Chinese Journal of Polymer Science 2024年第8期42卷 1210-1216页

作者： Li-Bang Xiao zi-Han Wu Jun-Jie Xin yuan-Peng Cheng Bo Gui Jun-Liang sun Cheng Wang College of Chemistry and Molecular Sciences Wuhan UniversityWuhan 430072China College of Chemistry and Molecular Engineering Beijing National Laboratory for Molecular SciencesPeking UniversityBeijing 100871China

Constructing three dimensional(3D)covalent organic frameworks(COFs)through the entanglement of two dimensional(2D)nets is a promising but underdeveloped ***,we report the design and synthesis of a fluorine functionalized 3DCOF(3D-An-COF-F)formed by entangled 2D sql *** structure of 3D-An-COF-F was determined by the combination of continuous rotation electron diffraction technique and modelling based on the chemical information from real ***,compared to the isostructural 3D-An-COF without F atom s,3DAn-COF-F showed an improved CO_(2)sorption ability and higher CO_(2)/N_(2)*** study not only demonstrated the generality of constructing 3D COFs with entangled 2D nets by introducing bulky groups vertically in planar building blocks,but also will expand the diversity of 3D COFs for various applications.

关键词： 3D covalent organic frameworks Fluorine Entangled 2D layers Electron diffraction CO_(2)adsorption

Modulation of d-orbital to realize enriched electronic cobalt sites in cobalt sulfide for enhanced hydrogen evolution in electrocatalytic water/seawater splitting

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Rare Metals 2024年第2期43卷 511-521页

作者： Jian-Peng sun Yu Zheng zi-Sheng Zhang Xiang-Chao Meng zi-Zhen Li Key Laboratory of Marine Chemistry Theory and Technology(Ministry of Education) College of Chemistry and Chemical EngineeringOcean University of ChinaQingdao266100China Shanxi Institute of Energy Taiyuan030600China Department of Chemical and Biological Engineering Faculty of EngineeringUniversity of OttawaOttawaONK1N6 N5Canada

Herein,a novel single-atomic Pt doping and interface-rich CoS/Co(OH)_(2)(Pt-CoS/Co(OH)_(2)/C)electrocatalyst has been successfully *** from precise regulation of d-orbital electronic structure modulation on Co site,Pt-CoS/Co(OH)_(2)/C exhibited remarkable HER activity and high stability for hydrogen evolution in splitting both water(73 mV@10 mA·cm^(−2)) and seawater(87 mV@10 mA·cm^(−2)).Notably,atomic Pt doping was introduced into CoS/Co(OH)_(2),which could produce local unbalanced Coulombic force and significantly increased the number of S vacancies,and then expose abundant Co ***,Co(OH)_(2) in Pt-CoS/Co(OH)_(2)/C could act as the adsorption sites for H_(2)O in hydrogen evolution reaction *** functional theory results also proved that atomic Pt doping,S vacancies and Co(OH)_(2) coupling could result in the formation of enriched electronic Co sites and optimize d_(z2) orbital electronic structure,and then realize the depth upward shift of d-band center and enhance the adsorption of H*on Co sites.

关键词： Electrocatalysts Hydrogen evolution reaction Pt-CoS/Co(OH)_(2) d-band center Electronic structure Water/seawater electrolysis

Reliable calculations of nuclear binding energies by the Gaussian process of machine learning

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Nuclear Science and Techniques 2024年第6期35卷 130-144页

作者： zi-Yi yuan Dong Bai Zhen Wang Zhong-Zhou Ren School of Physics Science and Engineering Tongji UniversityShanghai 200092China College of Science Hohai UniversityNanjing 211100China Key Laboratory of Advanced Micro-Structure Materials Ministry of EducationShanghai 200092China

Reliable calculations of nuclear binding energies are crucial for advancing the research of nuclear physics. Machine learning provides an innovative approach to exploring complex physical problems. In this study, the nuclear binding energies are modeled directly using a machine-learning method called the Gaussian process. First, the binding energies for 2238 nuclei with Z > 20 and N > 20 are calculated using the Gaussian process in a physically motivated feature space, yielding an average deviation of 0.046 MeV and a standard deviation of 0.066 MeV. The results show the good learning ability of the Gaussian process in the studies of binding energies. Then, the predictive power of the Gaussian process is studied by calculating the binding energies for 108 nuclei newly included in AME2020. The theoretical results are in good agreement with the experimental data, reflecting the good predictive power of the Gaussian process. Moreover, the α-decay energies for 1169 nuclei with 50 ≤ Z ≤ 110 are derived from the theoretical binding energies calculated using the Gaussian process. The average deviation and the standard deviation are, respectively, 0.047 MeV and 0.070 MeV. Noticeably, the calculated α-decay energies for the two new isotopes ^ (204 )Ac(Huang et al. Phys Lett B 834, 137484(2022)) and ^ (207) Th(Yang et al. Phys Rev C 105, L051302(2022)) agree well with the latest experimental data. These results demonstrate that the Gaussian process is reliable for the calculations of nuclear binding energies. Finally, the α-decay properties of some unknown actinide nuclei are predicted using the Gaussian process. The predicted results can be useful guides for future research on binding energies and α-decay properties.

关键词： Nuclear binding energies decay Machine learning Gaussian process

预测HL-2A托卡马克台基结构的MHD稳定性数值研究

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物理学报 2022年第22期71卷 178-191页

作者：孙梓源王元震刘悦大连理工大学物理学院三束材料改性教育部重点实验室大连116024 核工业西南物理研究院成都610041

基于HL-2A实验参数,利用TOQ程序构建了具有不同台基结构的平衡,在BOUT++三场模块下对台基磁流体力学(magnetohydrodynamics, MHD)稳定性进行数值模拟研究.线性模拟表明,减小台基高度、增大台基宽度、减小台基电流能够提高台基MHD稳定性... 详细信息

基于HL-2A实验参数,利用TOQ程序构建了具有不同台基结构的平衡,在BOUT++三场模块下对台基磁流体力学(magnetohydrodynamics, MHD)稳定性进行数值模拟研究.线性模拟表明,减小台基高度、增大台基宽度、减小台基电流能够提高台基MHD稳定性,利用色散关系理论,对上述现象进行解释.在MHD稳定性的前提下,预测了不同台基宽度对应的最高台基高度,对数据进行拟合,得到可以预测临界台基高度的公式,并在此基础上结合动理学气球模(kinetic ballooning mode, KBM)理论,同时预测了台基高度和宽度.本文也研究了台基结构对MHD不稳定模式的影响,线性模拟表明,台基高度能够微弱影响不稳定模式的径向模展宽;非线性模拟表明,不稳定模式的前期增长主要受单一主导模的影响,模式增长到一定大小会发生台基坍塌,爆发边缘局域模(edge localized mode, ELM), ELM尺寸的演化与主导模幅值的演化同步,总体来说具有较大线性增长率的平衡在非线性模拟中具有更大的ELM尺寸和更广范围的台基坍塌.

关键词： HL-2A 台基高度台基宽度 MHD稳定性边缘局域模

Pyrolysis Empirical Modeling of Polyester Glass Fiber Reinforced Plastics Using Sestak-Berggren Model Method

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Journal of Thermal Science 2024年第2期33卷 725-738页

作者： NAN Wei JI Wenhui yuan Yanping yuan Zhongyuan sun Yong School of Mechanical Engineering Southwest Jiaotong UniversityChengdu610031China CRRC Changchun Railway Vehicles Co. LtdChangchun130062China

Polyester Glass Fiber Reinforced Plastic(Polyester GFRP),a thermosetting plastic comprised of glass fiber and polyester polymer compounds,is extensively utilized in high-speed *** its pyrolysis mechanism is crucial as it significantly influences the combustion characteristics and fire safety ***,kinetic research on polyester GFRP primarily focuses on employing the Coats-Redfern method to derive a theoretical kinetic ***,the pyrolysis process of polyester GFRP is complex and the aforementioned theoretical model fails to accurately describe the pyrolysis ***,this study seeks to utilize the Sestak and Berggren(SB) model as a methodological approach to reveal the complex reaction mechanism during the pyrolysis *** on thermogravimetric analysis,the entire pyrolysis process of polyester GFRP is divided into two primary ***,model-free methods are employed to ascertain the activation energy and pre-exponential *** results show that the fitted empirical models of the two main pyrolysis stages are f(α)=(1-α)^(1.47)[-ln(1-α)]^(1.50) and f(α)=(1-α)^(1.77)[-ln(1-α)]^(1.72),*** predicted results are in good agreement with experimental data under different heating rates,which indicates that the empirical model can sufficiently describe the pyrolysis process of polyester GFRP.

关键词： polyester GFRP model-fitting methods empirical models pyrolysis

DNA hypermethylation of COL4A1 in ultraviolet-Binduced age-related cataract models in vitro and in vivo

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International Journal of Ophthalmology(English edition) 2024年第10期17卷 1791-1799页

作者： Li Wang Dan Zhu Yang Yang yuan He Jing sun Yi-Ming Li zi-Jing Wang Peng Li Department of Optometry Xi’an Medical UniversityXi’an 710021Shaanxi ProvinceChina Department of Ophthalmology the Second Affiliated Hospital of Xi’an Medical UniversityXi’an 710038Shaanxi ProvinceChina Department of Ophthalmology Xijing 986 HospitalFourth Military Medical UniversityXi’an 710054Shaanxi ProvinceChina

AIM:To explore the DNA methylation of COL4A1 in ultraviolet-B(UVB)-induced age-related cataract(ARC)models in vitro and in ***:Human lens epithelium B3(HLEB3)cells and Sprague Dawley rats were exposure to UVB *** MTT assay was utilized to evaluate cell *** cytometry was employed for analysis of cell apoptosis and cell ***4A1 expression in HLEB3 cells and anterior lens capsules were assessed using Western blot and reverse transcription-polymerase chain reaction(RTPCR).The localization of COL4A1 in HLEB3 cells was determined by *** methylation status of CpG islands located in COL4A1 promoter was verified using bisulfite-sequencing PCR(BSP).DNMTs and TETs mRNA levels was examined by ***:UVB exposure decreased HLEB3 cells proliferation,while increased the apoptosis rate and cells were arrested in G0/G1 ***4A1 expression was markedly inhibited in UVB treated cells compared to the *** status was detected in the CpG islands within COL4A1 promoter in HLEB3 cells subjected to UVB *** of DNMTs including DNMT1/2/3 were elevated in UVB treated HLEB3 cells compared to that in the controls,while expressions of TETs including TET1/2/3 showed the opposite *** from the UVB treated rat model further confirmed the decreased expression of COL4A1,hypermethylation status of the CpG islands at promoter of COL4A1 and abnormal expression of DNMT1/2/3 and TET1/2/in UVB exposure ***:DNA hypermethylation of COL4A1 promoter CpG islands is correlated with decreased COL4A1 expression in UVB induced HLEB3 cells and anterior lens capsules of rats.

关键词： human lens epithelium cells age-related cataract COL4A1 hypermethylation ultraviolet-B rat

Application of system identification in a practical active noise control system

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Control Theory and Technology 2024年第2期22卷 282-291页

作者： Yu yuan Zhaoyang sun Hongwei Zhang School of Mechanical Engineering Xihua UniversityChengdu610039SichuanChina School of Electrical Engineering Southwest Jiaotong UniversityChengdu611756SichuanChina School of Mechanical Engineering and Automation Harbin Institute of TechnologyShenzhen518055GuangdongChina

Noise pollution has become increasingly severe around the world due to fast urbanization. How to soundproof windows from outside noise is of significant interest for both academia and industry. This paper reports an experimental implementation of normalized minmax active noise control (ANC) algorithm on an open window system, where identifying the model of acoustic sound paths plays a central role. By doing this, traffic noise is attenuated by the ANC system, leading to a relatively quiet indoor environment, while the natural lighting and ventilation functions of a window are remained. Our experiments show that an average of 19 dB(A) noise reduction is achieved.

关键词： Active noise control Multi-input-multi-output system Normalized minimax algorithm System identification