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Combined use of fly ash and silica to prevent the long-term strength retrogression of oil well cement set and cured at HPHT conditions

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Petroleum Science 2024年第2期21卷 1122-1134页

作者： guo-Dong Cheng Xue-Yu Pang Jin-Sheng Sun Zheng-Song Qiu chuang-chuang Wang Jian-Kun Qin Ning li School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580ShandongChina National Key Laboratory of Deep Oil and Gas China University of Petroleum(East China)Qingdao266580ShandongChina Oil and Gas Engineering Research Institute(Tarim Oilfield Company) China National Petroleum CorporationTarim841000XinjiangChina

The long-term strength retrogression of silica-enriched oil well cement poses a significant threat to wellbore integrity in deep and ultra-deep wells, which is a major obstacle for deep petroleum and geothermal energy development. Previous attempts to address this problem has been unsatisfactory because they can only reduce the strength decline rate. This study presents a new solution to this problem by incorporating fly ash to the traditional silica-cement systems. The influences of fly ash and silica on the strength retrogression behavior of oil well cement systems directly set and cured under the condition of 200°C and 50 MPa are investigated. Test results indicate that the slurries containing only silica or fly ash experience severe strength retrogression from 2 to 30 d curing, while the slurries containing both fly ash and silica experience strength enhancement from 2 to 90 d. The strength test results are corroborated by further evidences from permeability tests as well as microstructure analysis of set cement. Composition of set cement evaluated by quantitative X-ray diffraction analyses with partial or no known crystal structure(PONKCS) method and thermogravimetry analyses revealed that the conversion of amorphous C-(A)-S-H to crystalline phases is the primary cause of long-term strength *** addition of fly ash can reduce the initial amount of C-(A)-S-H in the set cement, and its combined use with silica can prevent the crystallization of C-(A)-S-H, which is believed to be the working mechanism of this new admixture in improving long-term strength stability of oil well cement systems.

关键词： Fly ash Long-term strength retrogression High temperature Quantitative X-ray diffraction(QXRD) Partial or no known crystal structure(PONKCS)

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Macro Meso Response and Stress Wave Propagation Characteristics of MCT High-Voltage Switch Under Shock load

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Defence Technology（防务技术） 2024年第2期32卷 317-335页

作者： Yuyang guo chuang Chen Ruizhi Wang Enling Tang Key Laboratory of Transient Physical Mechanics and Energy Conversion Materials of liaoning Province Shenyang Ligong UniversityShenyang110159LiaoningChina

In order to study the dynamic and electrical coupling response characteristics of Metal Oxide Semiconductor Controlled Thyristor(MCT)high-voltage switch under the synergic action of mechanical load and high voltage,the separated Hopkinson pressure bar(SHPB)test system was used to simulate different impact load environments,and combined with the multi-layer high-voltage ceramic capacitor charging and discharging system,the instantaneous electrical signals of MCT high-voltage switch were *** with numerical simulation and theoretical analysis,the failure mode and stress wave propagation characteristics of MCT high voltage switch were *** mechanical and electrical coupling response characteristics and failure mechanism of MCT high voltage switch under dynamic load were revealed from macroscopic and microscopic *** results show that the damage modes of MCT high-voltage switches can be divided into non-functional damage,recoverable functional damage,non-recoverable damage and structural *** to the gap between the metal gate and the oxide layer,the insulating oxide layer was *** placing for a period of time,the elastic deformation of the metal gate partially recovered and the accumulated charge disappeared,which induced the recoverable functional damage failure of the *** addition,obvious cracks appeared on both sides of the monocrystalline silicon inside the MCT high-voltage switch,leading to unrecoverable damage of the device.

关键词： MCT Impact load Failure analysis Stress wave Numerical simulation

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Rock physical characteristics of deep dolomite under complex geological conditions: A case study of 4th Member of Sinian Dengying Formation in the Sichuan Basin, China

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Petroleum Science 2024年第4期21卷 2370-2382页

作者： chuang li Shu-Xin Pan Hong-Bin Wang Ji-Xin Deng Jian-guo Zhao Zhi li Yu Zhang Northwest Branch of Research Institute of Petroleum Exploration & Development Department of Geophysics and Exploration College of Geophysics Chengdu University of Technology State Key Laboratory of Petroleum Resources and Engineering China University of Petroleum (Beijing)

The deep-ultra deep carbonate reservoir in China, commonly subjected to modification of multi-stage diagenesis, has extremely high heterogeneity. Conventional rock physics analysis cannot accurately identify the elastic responses of reservoir. Here, the rock physics properties of the dolomite from the 4th Member of the Sinian Dengying Formation are experimentally measured, and the change law of rock physics characteristics is investigated within the framework of the diagenetic processes by the analysis of the elastic and petrologic characteristics, pore structure, and sedimentary environments. The results show that the differentiated diagenesis results in different pore structure characteristics and microtexture characteristics of the rock. The microbial dolomite of the algal mound-grain beach facies is subjected to the contemporaneous microbial dolomitization and seepage-reflux dolomitization, penecontemporaneous selective dissolution, burial dolomitization, and hydrothermal dolomitization. The resultant crystalline dolomite is found with one main type of the dolomite crystal contact boundaries,and the dissolution pore is extensive development. The siliceous, muddy, and limy dolomite of the interbeach sea environment mainly experiences the weak capillary concentration dolomitization, intensive mechanical compaction-induced densification, and burial dolomitization. Such crystalline dolomite is observed with four types of contact boundaries, namely the dolomite contact, clay contact, quartz contact, and calcite contact boundaries, and porosity mostly attributed to residual primary inter-granular or crystalline pores. The samples with the same crystal boundary condition have consistent correlations between the compressional-and shear-wave velocities, and between the compressional-wave velocity and the velocity ratio. Additionally, the variation of the acoustic velocity with effective pressure and the intensity of pore-scale fluid-related dispersion are controlled by t

关键词： Deep-ultra deep carbonate reservoirs Rock physics properties Dolomite Seismic elastic properties Micro-crack Pore structure types

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Ultrahigh strength and uniform corrosion in Zn-li alloys through ultrahigh pressure supersaturated solid solution treatment for biodegradable orthopedic applications

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Rare Metals 2024年第10期43卷 5284-5304页

作者： Wan-Ying li Yi-Long Dai Wen-Hao Cai Si-Han lin lin guo De-chuang Zhang Yuncang li Cuie Wen School of Materials Science and Engineering Xiangtan University Department of Prosthodontics Shanghai Ninth People′s HospitalShanghai Jiao Tong University Key Laboratory of Low Dimensional Materials&Application Technology Ministry of EducationXiangtan University School of Engineering RMIT UniversityMelbourne

Zn-li alloys are considered promising candidate materials for biodegradable orthopedic implant applications due to their high mechanical performance and good ***,the presence of a large number of second-phase particles in this class of Zn alloys can lead to severe localized degradation due to micro-galvanic corrosion,which is detrimental to the mechanical integrity of the alloys during tissue healing in the human *** this study we report ultrahigh strength,uniform corrosion,good cytocompatibility,and effective antibacterial ability in Zn-x li（x=0.3,0.5,0.7;wt%） alloys achieved through supersaturated solid solution treatment （SSST） at 375℃ under ultrahigh pressure of 3 GPa.A high concentration of β-liZn4phases coexisted with the-Zn matrix in the as-cast Zn-x li alloys,whereas almost all the li dissolved into the-Zn matrix of SSST *** yield strength was 437 MPa for SSST Zn-0.3li,592 MPa for SSST Zn-0.5 li and 686 MPa for SSST *** SSST Zn-li alloys showed uniform degradation with remarkably reduced degradation rates compared to their as-cast *** 25% concentration extracts of the Zn-x li alloys demonstrated no cytotoxicity toward MC3T3-E1 cells,and the alloys exhibited effective antibacterial ability agains methicillin-resistant staphylococcus aureus.

关键词： Corrosion behavior Mechanical property Supersaturated solid solution treatment (SSST) Ultrahigh pressure Zn-li alloy

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T-tube bridging fistula jejunal anastomosis for treatment of pancreatic lumbar dorsal fistula after necrotizing pancreatitis

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Hepatobiliary & Pancreatic Diseases International 2024年第4期23卷 428-430页

作者： Su-Lai liu guo-Guang li Wei Cheng chuang Peng Ying-Hui Song Department of Hepatobiliary Surgery Hunan Provincial People’s Hospital/The First Affiliated Hospital of Hunan Normal UniversityChangsha 410000China

Infectious pancreatic necrosis causes external pancreatic fistula in some ***,external pancreatic fistula requires fistula-gastric and/or intestinal anastomosis,and digestive endoscopic interventional treatment[1–3].It is especially difficult to treat external pancreatic fistulas with small fistulas where the external fistula is located in the lower *** common treatment is to remove the body and tail of the pancreas and the *** operation is very traumatic.A new pancreatic fistula may still occur at the pancreatic *** above operations may lead to unnecessary resection of the spleen,colon injury and other *** order to solve this problem,we innovatively used T-tube bridging fistula jejunal anastomosis plus continuous negative pressure suction to treat three cases of external pancreatic fistulas in the lower back,and all of them achieved good results.

关键词： fistula anastomosis spleen

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light People:*** Mazur speaks about ultrafast optics and education

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light(Science & Applications) 2024年第3期13卷 402-406页

作者： Chenzi guo Yang li Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchunChina State Key Laboratory of Precision Measurement Technology and Instrument Department of Precision InstrumentTsinghua UniversityBeijingChina

*** Mazur is a great influencer over and beyond the optics *** a physicist,he is a pioneer of ultrafast optics and was one of the inventors of colliding-pulse mode-locked *** an educator,he not only gave talks to thousands,but also revolutionized teaching with his globally renowned methodology“Peer Instruction”.As a leader and entrepreneur,he co-founded several companies and was President of Optica(formerly the Optical Society)and currently is the Chair of the Optica ***,light:Science&Applications talked with *** Mazur about his opinions on research,education and *** full interview video can be found in the Supplementary File.

关键词： optics education companies

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A unified stochastic damage model for concrete based on multi-scale energy dissipation analysis

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Science China(Technological Sciences) 2024年第3期67卷 863-877页

作者： guo ChengGong li Jie College of Civil Engineering Tongji UniversityShanghai 200092China State Key Laboratory of Disaster Reduction in Civil Engineering Shanghai 200092China

This work proposes a unified damage model for concrete within the framework of stochastic damage mechanics. Based on the micro-meso stochastic fracture model(MMSF), the nonlinear energy dissipation process of the microspring from nanoscale to microscale is investigated. In nanoscale, the rate process theory is adopted to describe the crack growth rate;therefore, the corresponding energy dissipation caused by a representative crack propagation can be obtained. The scale gap from nanoscale to microscale is bridged by a crack hierarchy model. Thus, the total energy dissipated by all cracks from the nanoscale to the microscale is gained. It is found that the fracture strain of the microspring can be derived from the above multi-scale energy dissipation analysis. When energy dissipation is regarded as some microdamage to the microspring, the constitutive law of the microspring is no longer linearly elastic, as previously assumed. By changing the expression of the damage evolution law from fracture strain to energy dissipation threshold, the new damage evolution model is derived. The proposed model can not only replicate the original static model but also extend to cases of rate dependence. By deriving the fracture strain under different strain rates, the rate sensitivity of concrete materials can be reflected. The model parameters can be conveniently obtained by identifying them with experimental data. Finally, several numerical examples are presented to verify the proposed model.

关键词： concrete damage model stochastic damage rate dependent energy dissipation

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Genome-wide analysis of Panonychus citrimicro RNAs witha focus on potential insecticidal activity of 4 micro RNAs toeggs and nymphs

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Insect Science 2024年第2期31卷 354-370页

作者： Chuan-Zhen li Yu-Hang liu Deng Pan Meng-Hao Xia Qiang Zhang Yu-chuang li guo-Rui Yuan Jin-Jun Wang Wei Dou Key Laboratory of Entomology and Pest Control Engineering College of Plant ProtectionAcademy of Agricultural SciencesSouthwestUniversityChongqingChina Key Laboratory of Agricultural Biosafety and Green Production of Upper Yangtze River(Ministry of Education) Academy of Agricultural SciencesSouthwest UniversityChongqingChina

Panonychus citriMcGregor(Acari:Tetranychidae),a destructive citrus pest,causes considerable annual economic losses due to its short lifespan and rapid ***(miRNA)-induced RNA interference is a promising approachfor pest control because of endogenous regulation of pest growth and *** for miRNAs with potential insecticidal activity ***,genome-wide analysis ofmiRNAs at different developmental stages was conducted,resulting in the identificationof 136 miRNAs,including 73 known and 63 novel miRNAs.A total of 17 isomiRNAsand 12 duplicated miRNAs were ***-1 and miR-252-5p were identified asreference miRNAs *** *** on differential expressionanalysis,treatments with miR-let-7a and miR-315 mimics and the miR-let-7a antagomirsignificantly reduced the egg hatch rate and resulted in abnormal egg ***-expression or downregulation of miR-34-5p and miR-305-5p through feeding significantlydecreased the adult eclosion rate and caused molting *** 4 miRNAs,miR-let-7a,miR-315,miR-34-5p,and miR-305-5p,had important regulatory functions and insectici-dal properties in egg hatching and adult *** general,these data advance our un-derstanding of miRNAs in mite biology,which can assist future studies on insect-specificmiRNA-based green pest control technology.

关键词： growth and development microRNAs Panonychus citri referencemiRNAs regulation small RNA libraries

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Predicting torsional capacity of reinforced concrete members by data-driven machine learning models

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Frontiers of Structural and Civil Engineering 2024年第3期18卷 444-460页

作者： Shenggang CHEN Congcong CHEN Shengyuan li Junying guo Quanquan guo Chaolai li School of Mechanics and Civil Engineering China University of Mining and TechnologyXuzhou 211116China Jiangsu Key Laboratory Environmental Impact and Structural Safety in Engineering China University of Mining and TechnologyXuzhou 211116China China Nuclear Power Design Co.Ltd. Shenzhen 518031China School of transportation and science engineering Beihang UniversityBeijing 100191China China Construction First Group Corporation limited Beijing 100161China

Due to the complicated three-dimensional behaviors and testing limitations of reinforced concrete(RC)members in torsion,torsional mechanism exploration and torsional performance prediction have always been *** the present paper,several machine learning models were applied to predict the torsional capacity of RC *** results of a total of 287 torsional specimens were collected through an overall literature *** of extreme gradient boosting machine(XGBM),random forest regression,back propagation artificial neural network and support vector machine,were trained and tested by 10-fold cross-validation *** performances of proposed machine learning models were evaluated and compared,both with each other and with the calculated results of existing design codes,i.e.,GB 50010,ACI 318-19,and Eurocode *** results demonstrated that better predictive performance was achieved by machine learning models,whereas GB 50010 slightly overestimated the torsional capacity,and ACI 318-19 and Eurocode 2 underestimated it,especially in the case of ACI *** XGBM model gave the most favorable predictions with R^(2)=0.999,RMSE=1.386,MAE=0.86,andλ=***,strength of concrete was the most sensitive input parameters affecting the reliability of the predictive model,followed by transverse-to-longitudinal reinforcement ratio and total reinforcement ratio.

关键词： RC members torsional capacity machine learning models design codes

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Stable graphene oxide-based lyotropic liquid crystals for interfacial lubrication

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Friction 2024年第5期12卷 954-967页

作者： Yumei guo Hanglin li Jiusheng li Xiangqiong ZENG Laboratory for Advanced Lubricating Materials Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai201210China University of Chinese Academy of Sciences Beijing100049China

Lyotropic liquid crystals have lubricating properties due to their ordered assembly and fluidity,whose mesogens are often characterized by amphiphilic *** the attention that graphene oxide(GO)has been studied as a novel amphiphilic lyotropic mesogen this decade,and GO applied as a lubrication additive has been demonstrated in both oil and water-based systems,little research reveals the interfacial lubrication of GO liquid crystals *** work reports that GO aqueous dispersion can form lyotropic liquid crystals above a specific critical concentration of 5.00 mg/mL,providing a form of stable water-based lubricant,which can keep stable for several months and can reduce friction by 37.3%and wear by 25.24%.The liquid crystal phase was verified by polarizing microscope and synchrotron radiation small-angle X-ray scattering,and its rheological properties and viscoelasticity were studied by interfacial *** formation of lyotropic liquid crystals can enhance the stability of GO aqueous dispersions at high density,simultaneously ensuring friction decrease and anti-wear *** is attributed to the stable nematic network by the ordered GO *** ordered assembly structure bears vertical shear force,therefore,reducing the *** is also assumed that the wide lateral size of graphene oxide promotes the nematic phase thus smoothes the graphene oxide film composed spontaneously under the coincidence of lamellar liquid crystal and 2D layered *** this work,the interlayer lubrication of GO was optimized,and the problem of GO dispersion sedimentation was solved by *** range of interfacial lubrication of GO aqueous dispersion has been expanded and the synergistic effect is conducive to the environmentally friendly lubricants.

关键词： lyotropic liquid crystal graphene oxide aqueous lubrication tribological behavior

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