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Multiple damage zones around hydraulic fractures generated by high-frequency pulsating hydraulic fracturing

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Petroleum Science 2024年第4期21卷 2688-2702页

作者： Yan Peng Sheng-Jie Wei guang-Qing Zhang Da-Wei zhou Chuang-Chao Xu School of Petroleum Engineering China University of Petroleum Petrochina Changqing Oilfield Company

Pulsating hydraulic fracturing(PHF) is a promising fracturing method and can generate a dynamic periodic pressure. The periodic pressure can induce fatigue failure of rocks and decrease initiation pressure of fracture. If the frequency of periodic pressure exceeds 10 Hz, the distribution of pressure along the main fracture will be heterogeneous, which is much different from the one induced by the common fracturing method. In this study, the impact of this special spatial feature of pressure on hydraulic fracture is mainly investigated. A coupled numerical simulation model is first proposed and verified through experimental and theoretical solutions. The mechanism of secondary fracture initiation around the main fracture is then discovered. In addition, sensitivity studies are conducted to find out the application potential of this new method. The results show that(1) this coupled numerical simulation model is accurate. Through comparison with experimental and theoretical data, the average error of this coupled model is less than 1.01%.(2. Even if a reservoir has no natural fracture, this heterogeneous distribution pressure can also cause many secondary fractures around the main fracture.(3) The mechanism of secondary fracture initiation is that this heterogeneous distribution pressure causes tensile stress at many locations along the main fracture.(4) Through adjusting the stimulation parameters, the stimulation efficiency can be improved. The average and amplitude of pressure can increase possibility of secondary fracture initiation. The frequency of this periodic pressure can increase number of secondary fractures. Even 6 secondary fractures along a 100 m-length main fracture can be generated.(5) The influence magnitudes of stimulation parameters are larger than ones of geomechanical properties, therefore, this new fracturing method has a wide application potential.

关键词： Tight reservoir Reservoir stimulation Numerical simulation Secondary fracture Fracture initiation

Synthesis-temperature-dependent phase composition manipulation toward high thermoelectric performance in tetrahedrites

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Journal of Materials Science & Technology 2024年第1期168卷 124-130页

作者： Yiqing Wei Jiaqi Liu Zien Cheng Pengfei Jiang Zizhen zhou Bin Zhang Guoyu Wang guang Han Xu Lu Xiaoyuan zhou Center of Quantum Materials and Devices College of PhysicsChongqing UniversityChongqing 401331China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China College of Chemistry and Chemical Engineering Chongqing UniversityChongqing 401331China Analytical and Testing Center Chongqing UniversityChongqing 401331China

Tetrahedrite,an Earth-abundant natural mineral,has attracted extensive research interest because of its excellent thermoelectric ***,tetrahedrite samples comprising Cu-poor Cu_(12.Sb_(4)S_(13)and Cu-rich Cu_(14)Sb_(4)S_(13)phases have been synthesized using a colloidal method,in which the ratio of two phases is manipulated by controlling the synthesis temperature to improve the thermoelectric *** is found that an ultralow total thermal conductivity of∼0.3 W m^(−1)K^(−1)at 72. K is realized in the sample with a Cu-rich phase fraction of∼50%,which can be attributed to maximized phonon scattering by phase *** a result,combined with a decent power factor,this sample obtains an optimal zT of 1.15,which is about 85%higher than that of the sample with a Cu-rich phase fraction of∼64%and comparable to zT values of other eco-friendly,abundant Cu-based thermoelectric *** work demonstrates an effective synthesis-temperature-dependent phase composition manipulation strategy toward enhanced thermoelectric performance in tetrahedrites.

关键词： Tetrahedrite Thermoelectric Colloidal method Phase manipulation Thermal conductivity

Numerical investigation on compressible flow around a cylinder in proximity to the heated wall

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Journal of Hydrodynamics 2024年第3期36卷 519-533页

作者： Yu-lu Liu Jun-wang Qu Yi-zhou Tao Yong-guang Lyu Xiang Qiu Shanghai Institute of Technology School of ScienceShanghai201418China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai200072China

In this study,direct numerical simulations were conducted to investigate the compressible flow around a circular cylinder near a heated wall at a Reynolds number(Re)of 500 and a Mach number(Ma)of *** heating ratio T^(*)ranging from 1.0 to 1.6 represents the different situations of a heated wall,whereas the gap ratio ranges from 0.3 to *** study analyzed the impact of heating effect and wall proximity on flow characteristics and aerodynamic *** results indicated that the stability of the flow was enhanced as the gap ratio decreased or the heating ratio *** the calculation of enstrophy,it was found that the strength of shedding vortices weakens with a decrease in gap ratio or an increase in heating ***,the mean drag coefficient decreases as the heating ratio increases or the gap ratio *** contrast,the mean lift coefficient initially decreases and then increases as the gap ratio ***,the drag reduction mechanism was analyzed by examining the pressure distribution on the surface of the cylinder.

关键词： Compressible flow wall proximity heating effect stability enstrophy

Energy distributions of the large-scale horizontal currents caused by wind in the baroclinic ocean

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Science china Earth Sciences 2005年第12期48卷 2267-2275页

作者： zhou Lei1, TIAN Jiwei1 & WANG Dongxiao2.1. Physical Oceanography Laboratory, Ocean university of{2., Qingdao 2.6003,{2. 2. Key Laboratory of Tropical Marine Environmental Dynamics, south{2. Sea Institute of Oceanology, Chinese Academy of Sciences, guangdong 510301,{2. 1. Physical Oceanography Laboratory Ocean University of China 266003 Qingdao China 2. Key Laboratory of Tropical Marine Environmental Dynamics South China Sea Institute of Oceanology Chinese Academy of Sciences 510301 Guangdong China

Ocean current data for nearly 3 months in the south china Sea (SCS), combined with the NCEP/NCAR reanalysis wind data, are analyzed. The results indicate that the wind en-ergy enters the upper mixed layer in a wide continuous frequency band. In addition, the interac-tion between the low-frequency wind anomaly and the low-frequency current anomaly is the most ‘effective’ way for the energy input from the wind to the upper ocean. However, only the inertial and the near inertial energy propagate downwards through the upper mixed layer. The down-ward-propagating energy is distributed into the barotropic currents, the baroclinic currents and each mode of the baroclinic currents following the {2. distributions. The energy change ratios between the barotropic motion to the baroclinic motion induced by the wind present a {2. distribution of N (0.02.2. 0.3947). The energy change ratios of the first 4 baroclinic modes to the whole baroclinic currents also follow the {2. distributions. The first baroclinic mode follows N (0.2.2., 0.1872., the second N (0.1979, 0.1504), the third N (0.1331, 0.1633), and the fourth N (0.0650, 0.1540), respectively.

关键词： wind anomaly, ocean current anomaly, energy transportation, wide frequency band, near-inertial fre-quency, energy distribution.

Edaphic factors determining variation of two ecotypes of Leymus chinensis in North china

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Progress in Natural Science:Materials International 2006年第11期16卷 1150-1155页

作者： zhou Chan~1 and YANG Yunfei~2.*(1. MOE Key Laboratory of Environmental Change and Natural Disasters, College of Resources Science and Technology, Beijing normal {2., Beijing 100875, china 2. Key Laboratory of Vegetation Ecology, Ministry of Education, Institute of Grassland Science, Northeast normal {2., Changchun 13002., china) [a]MOE Key Laboratory of Environmental Change and Natural Disasters College of Resources Science and Technology Beijing Normal University Beijing China [b]Key Laboratory of Vegetation Ecology Ministry of Education Institute of Grassland Science Northeast Normal University Changchun China

To identify ecotypic variation of L. chinensis, the physiological characteristics and environmental factors were measured and assessed for grey-green and yellow-green ecotypes of L. chinensis grown in the salt-alkalized and aeolian sandy soils. Although both ecotypes presented a similar salt-alkaline tolerance under the experimental conditions, they differed in several aspects. The L. chinensis grown in the aeolian sandy soils had higher water potential and chlorophyll content and lower proline content in their leaves than those grown in the salt-alkalized habitat, and the grey-green ecotype of L. chinensis in both types of soils had higher water potential, chlorophyll and proline contents than the yellow-green ecotype. Besides, grey-green ecotypes had higher salt-alkaline tolerance than the yellow-green ecotype. The stepwise regression analysis showed that soil conductance and pH value were the main ecological factors affecting the physiology of L. chinensis. From the natural distribution of the two ecotypes, we considered that salt-alkaline in the soils is the leading factor in determining ecotypic variation of L. chinensis. The two ecotypes were first named grey-green and yellow-green ecotypes respectively.

关键词： L.chinensis ecotype adaptability variation ecological factor salt-alkaline in soil.

Quick image-processing method of UAV without control points data in earthquake disaster area

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中国有色金属学会会刊：英文版 2011年第S3期21卷 523-528页

作者： LI Chang-chun1, ZHANG guang-sheng1, LEI Tian-jie2. 3, GONG A-du2. 3 1. School of Surveying & Land Information Engineering, Henan Polytechnic university, Jiaozuo 454000,{2. 2. Key Laboratory of Environmental Change and Natural Disaster, Ministry of Education, Beijing normal university, Beijing 100875,{2. 3. Ministry of Civil Affairs/Ministry of Education of{2. Academy of Disaster Reduction and Emergency Management, Beijing normal university, Beijing 100875,{2. [a] School of Surveying & Land Information Engineering Henan Polytechnic University Jiaozuo 454000 China [b] Key Laboratory of Environmental Change and Natural Disaster Ministry of Education Beijing Normal University Beijing 100875 China [c] Ministry of Civil Affairs/Ministry of Education of china Academy of Disaster Reduction and Emergency Management Beijing Normal University Beijing 100875 China

The methods of unmanned aerial vehicles images splicing rapidly and rectifying without control points data, only using auxiliary data recorded by unmanned aerial vehicle (UAV) system, were researched. Two algorithms were proposed, including UAV images auto- splicing rapidly after image blocking and UAV images rectifying based on pseudo center points of auxiliary data. When SIFT algorithm for UAV images splicing is applied, the accuracy is very high, but the efficiency is very low. The splicing efficiency is improved greatly based on SIFT algorithm after image blocking. The results show that rectifying accuracy is very high and has no visual dislocation when pseudo center points of auxiliary data is applied.

关键词： unmanned aerial vehicles SIFT algorithm blocking quickly splicing rectification

Cross-shore suspended sediment flux in the salt marsh pioneer zone of Chongming eastern beach in the Chang- jiang Estuary in china

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Acta Oceanologica Sinica 2010年第6期29卷 62-72页

作者： WANG Chu YAO Dongjing HE Baogen zhou Naisheng XU Shiyuan Department of geography Shanghai Normal University Shanghai 200234 China Department of geography College of Resource and Environmental Science East China Normal University Shanghai 200062 China

Between April 2.02.and April 2.03,in situ measurements of water depth,current velocity and suspended sediment content were carried out in edge region of East Chongming salt marsh and neighboring bald flat in the Changjiang （Yangtze） Estuary under different weather ***-shore suspended sediment flux was calculated and *** results show that under calm weather conditions,the current velocity process in bald field and salt marsh area varied differently during semidiurnal tidal *** to current velocity asymmetry,mean SSC during flood tide phase was 1.8 times higher than that of ebb tide *** a result,net onshore sediment flux controlled cross-shore suspended sediment transport process and salt marsh pioneer zone was generally *** was significant positive correlation between total sediment flux and quartic power of maximum water *** indicates that tidal ranges dominate suspended sediment transport and sedimentation process in the salt marsh pioneer zone under the calm weather *** sedimentation rate on the adjacent mudflat was higher than the salt marsh,which induced stable accreting of salt marsh towards the *** wind events enhanced SSC and current velocity during the semidiurnal *** the remarkable onshore net sediment flux could occur on the high marsh and mudflat close to the marsh fringe during the short period under the rough weather condition.

关键词： current velocity suspended sediment content flux salt marsh eastern beach

Purification and characterization of a novel cholesterol-lowering protein from the seeds of Senna obtusifolia

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Science china(Life Sciences) 2008年第11期51卷 1020-1024页

作者： LI ChuHua1, LI Mei2. CHANG WenRui2.& GUO BaoJiang1 1 College of Life Sciences, south china normal university, guangdong Provincial Key Lab of Biotechnology of Plant Development, guang-zhou 510631, china 2.Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, china 1. College of Life Sciences South China Normal University Guangdong Provincial Key Lab of Biotechnology of Plant Development Guangzhou 510631 China 2. Institute of Biophysics Chinese Academy of Sciences Beijing 100101 China

"Juemingzi", a source of traditional Chinese herbal medicine, has been demonstrated to play a role in decreasing serum cholesterol concentration. In this study, a novel protein, which has shown an in-hibitory effect on cholesterol biosynthesis, was isolated from Senna obtusifolia L. seed by gel filtration and ion exchange chromatography. The novel protein’s molecular mass was 19.7 kD and its pI was 4.80. Both SDS-PAGE and isoelectric-focusing (IEF) revealed a single Coomassie brilliant blue stained band, indicating that the novel protein was a single peptide. The N-terminal amino acid sequence of the pro-tein was IPYISASFPLNIEFLPSE, which had no similarity with any other protein sequences in the NCBI protein database. Circular dichroism (CD) signals indicated that S. obtusifolia seed protein contained 12.5% α-helix, 55.6% β-sheet, and 31.9% random coil.

关键词： Senna obtusifolia L. seed novel protein purification biochemical properties cholesterol biosynthesis

Understand the Temperature Sensing Behavior of Solid-state Polymerized PEDOT Hybrid Based on X-ray Scattering Studies

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Chinese Journal of Polymer Science 2024年第1期42卷 105-112,I0010页

作者： Zhen-Hang He guang-Feng Liu Ze-Kun zhou Zhen Liu Yi-Shu Zeng Peng Zhang School of Materials Science and Engineering Key Laboratory for Polymeric Composite and Functional Materials of Ministry of EducationSun Yat-sen UniversityGuangzhou 510275China Shanghai Advanced Research Institute(Zhangjiang Laboratory) Chinese Academy of SciencesShanghai 201204China

Poly(3,4-ethylenedioxythiophene)(PEDOT) is one of the most successful conductive polymers that recently has been used in wearable sensors for human health monitoring. In this work, we prepared a series of PEDOT hybrids consisting of PEDOT, sodium poly(styrene sulfonate)(PSSNa) and polyethylene oxide(PEO), and their preparation could be scaled-up via an adapted solid-state polymerization process. The resistance of the as-prepared PEDOT:PSS/PEO hybrid shows clear temperature response, i.e., it decreases almost linearly with the temperature increase. To understand this phenomenon, the in situ synchrotron radiation wide-and small-angle X-ray scattering(WAXS/SAXS) characterizations were undertaken to study the temperature-dependent microstructure change of the PEDOT:PSS/PEO hybrid. It demonstrated that PEDOT formed conductive paths in the hybrids, which were not destroyed by the PEO crystallization. As temperature increased, the PEO crystals' melting and the accompanying reorganization of PEDOT chains endowed the hybrid sample temperature responsiveness. Based on these fundamental knowledges, the hybrid materials were used to fabricate flexible wearable sensor that showing temperature sensing performance with an accuracy of 1 ℃. These findings shed lights on the scalable manufacturing of wearable sensors for body temperature monitoring.

关键词： Solid-state polymerization PEDOT hybrid Structure-property correlation X-ray scattering