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Research advances in enhanced coal seam gas extraction by controllable shock wave fracturing

International Journal of Coal Science & Technology 2024年第3期11卷 1-31页

作者： Chaojun Fan hao Sun Sheng Li Lei Yang bin Xiao Zhenhua Yang Mingkun Luo Xiaofeng Jiang Lijun Zhou College of Mining Liaoning Technical UniversityFuxin123000China College of Safety Science and Engineering Liaoning Technical UniversityFuxin123000China Energy Business Department Shanxi Lu’an Chemical GroupChangzhi046200China

With the continuous increase of mining in depth,the gas extraction faces the challenges of low permeability,great ground stress,high temperature and large gas pressure in coal *** controllable shock wave(CSW),as a new method for enhancing permeability of coal seam to improve gas extraction,features in the advantages of high efficiency,eco-friendly,and low *** order to better utilize the CSW into gas extraction in coal mine,the mechanism and feasibility of CSW enhanced extraction need to be *** this paper,the basic principles,the experimental tests,the mathematical models,and the on-site tests of CSW fracturing coal seams are reviewed,thereby its future research directions are *** on the different media between electrodes,the CSW can be divided into three categories:hydraulic effect,wire explosion and excitation of energetic materials by detonating *** the process of propagation and attenuation of the high-energy shock wave in coal,the shock wave and bubble pulsation work together to produce an enhanced permeability effect on the coal *** stronger the strength of the CSW is,the more cracks created in the coal is,and the greater the length,width and area of the cracks *** repeated shock on the coal seam is conducive to the formation of complex network fracture system as well as the reduction of coal seam strength,but excessive shock frequency will also damage the coal structure,resulting in the limited effect of the enhanced gas *** the influence of ground stress,the crack propagation in coal seam will be *** difference of horizontal principal stress has a significant impact on the shape,propagation direction and connectivity of the CSW induced *** permeability enhancement effect of CSW is affected by the breakage degree of coal *** shock wave is absorbed by the broken coal,which may hinder the propagation of CSW,resulting in a poor effect of permeability *** arranging two a

关键词： Controllable shock wave Permeability enhancement Gas extraction Basic principle Experimental test Mathematical models On-site test

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Exceptional electrostrain with minimal hysteresis and superior temperature stability under low electric field in KNN-based lead-free piezoceramics

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Journal of Advanced Ceramics 2024年第3期13卷 364-372页

作者： Huan Liu Yijin hao Ziqi Yang Tianyi Feng bin Su Xin Zhang Mengping Xue Bo-Ping Zhang Jing-Feng Li Beijing Municipal Key Laboratory of New Energy Materials and Technologies School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Over the past two decades,(K_(0.5)Na_(0.5))NbO_(3)(KNN)-based lead-free piezoelectric ceramics have made significant ***,attaining a high electrostrain with remarkable temperature stability and minimal hysteresis under low electric fields has remained a significant *** address this long-standing issue,we have employed a collaborative approach that combines defect engineering,phase engineering,and relaxation *** LKNNS-6BZH ceramic,when sintered at T_(sint)=1170℃,demonstrates an impressive electrostrain with a d_(33) value of 0.276%and 1379 pm·V^(-1)under 20 kV·cm^(-1),which is comparable to or even surpasses that of other lead-free and Pb(Zr,Ti)O_(3)***,the electrostrain performance of this ceramic remains stable up to a temperature of 125℃,with the lowest hysteresis observed at 9.73%under 40 kV·cm^(-1).These excellent overall performances are attributed to the presence of defect dipoles involving V′_(A)-V∙∙_(O) and B′_(Nb)-V∙∙O,the coexistence of R-O-T multiphase,and the tuning of the trade-off between long-range ordering and local *** work provides a lead-free alternative for piezoelectric actuators and a paradigm for designing piezoelectric materials with outstanding comprehensive performance under low electric fields.

关键词： lead-free piezoelectric ceramics temperature stability electrostrain potassium sodium niobate low hysteresis

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Improved RF power performance via electrostatic shielding effect using AlGaN/GaN/graded-AlGaN/GaN double-channel structure

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Science China(Information Sciences) 2024年第4期67卷 341-342页

作者： Chunzhou SHI Ling YANG Meng ZHANG hao LU Mei WU bin HOU Xuerui NIU Qian YU Wenliang LIU Wenze GAO Xiaohua MA Yue hao School of Advanced Materials and Nanotechnology Xidian University State Key Discipline Laboratory of Wide Bandgap Semiconductor Technology Xidian University

GaN-based high-electric-mobility transistors(HEMTs) have been investigated thoroughly because of their promising applications in high-frequency,-voltage, and-power applications. However, the theoretical material limit prevents conventional single-heterostructure GaN HEMTs from achieving high performance despite numerous efforts [1–3].

关键词： Drain current

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Formation and rupture of liver hematomas caused by intrahepatic gallbladder perforation:A case report and review of literature

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World Journal of Gastrointestinal Surgery 2024年第10期16卷 3301-3311页

作者： Hong-Wei Huang hao wang Chao Leng bin Mei Hepatic Surgery Center Tongji HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030Hubei ProvinceChina

BACKGROUND Gallbladder perforation is a serious complication of acute *** perforation is a rare but life-threatening situation that can lead to the formation and rupture of liver ***,we report a case of a ruptured intrahepatic hematoma caused by intrahepatic gallbladder perforation,and we present a literature *** SUMMARY A 70-year-old male was admitted to the hospital with a complaint of right upper quadrant abdominal pain,flustering and *** preoperative diagnosis was a ruptured malignant liver tumor,and the patient’s medical images and increased level of carbohydrate antigen-199 suggested that the gallbladder had been ***,the tumor was proven to be a liver hematoma secondary to gallbladder perforation after *** patient was discharged uneventfully on the fifteenth postoperative *** Intrahepatic gallbladder perforation is difficult to diagnose *** examinations play a crucial role in the diagnosis but only for partial *** diagnosis and appropriate surgery are key to managing this rare condition.

关键词： Intrahepatic gallbladder perforation Cholecystitis Liver rupture Intraperitoneal hemorrhage Case report

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Typhoon-Induced Ocean Waves and Stokes Drift:A Case Study of Typhoon Mangkhut(2018)

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China Ocean Engineering 2024年第4期38卷 711-724页

作者： WU Zhi-yuan GAO Kai CHEN Jie ZHANG hao-jian DENG bin JIANG Chang-bo LIU Yi-zhuang LYU Zhao YAN Ren School of Hydraulic and Environmental Engineering Changsha University of Science&TechnologyChangsha 410114China Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province Changsha 410114China State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai UniversityNanjing 210024China State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China School of Civil Engineering Hunan University of TechnologyZhuzhou 412007China

Ocean waves and Stokes drift are generated by *** study investigated the characteristics of ocean waves and wave-induced Stokes drift and their effects during Typhoon Mangkhut using European Centre for MediumRange Weather Forecasts(ECMWF)ERA5 datasets and observational *** results revealed that the typhoon generated intense cyclones and huge typhoon waves with a maximum wind speed of 45 m/s,a minimum pressure of955 h Pa,and a maximum significant wave height of 12 *** Stokes drift caused by typhoon waves exceeded 0.6m/s,the Stokes depth scale exceeded 18 m,and the maximum Stokes transport reached 6 m^(2)/*** spatial distribution of 10-m wind speed,typhoon wave height,Stokes drift,Stokes depth,and Stokes transport during the typhoon was highly correlated with the typhoon *** distribution along the typhoon track showed significant zonal asymmetry,with greater intensity on the right side of the typhoon track than on the left *** findings provide important insights into the impact of typhoons on ocean waves and Stokes drift,thus improving our understanding of the interactions between typhoons and the ocean *** study also investigated the contribution of Stokes transport to the total net transport during typhoons using Ekman-Stokes Numbers as a comparative *** results indicated that the ratio of Stokes transport to the total net transport reached up to 50%within the typhoon radius,while it was approximately 30%outside the *** Stokes transport induced by typhoon waves led to divergence in the transport direction,which resulted in upwelling of the lower ocean as a compensation ***,Stokes transport played a crucial role in the vertical mixing of the ocean during *** findings suggested that Stokes transport should be paid more attention to,particularly in high latitude ocean regions,where strong winds can amplify its effects.

关键词： Stokes drift typhoon waves Ekman-Stokes transport vertical mixing Typhoon Mangkhut

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Reducing Operation Emissions and Improving Work Efficiency Using a Pure Electric Wheel Drive Tractor

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Engineering 2024年第6期37卷 230-245页

作者： Chang-Kai Wen Wen Ren Qing-Zhen Zhu Chun-Jiang Zhao Zhen-hao Luo Sheng-Li Zhang bin Xie Zhi-Jun Meng Research Center of Intelligent Equipment Beijing Academy of Agriculture and Forestry SciencesBeijing 100097China State Key Laboratory of Intelligent Agricultural Power Equipment Beijing 100097China BYD Company Limited Shenzhen 518118China College of Agricultural Engineering Jiangsu UniversityZhenjiang 212013China College of Engineering China Agricultural UniversityBeijing 100083China

In response to the problems of excessive greenhouse-gas and particulate emissions and the low traction efficiency of conventional diesel tractors in the field,a purely electric wheel-side drive tractor was studied,including an electric motor drive system,a battery ballast system,and an electro–hydraulic suspension *** paper develops a dynamics model of an electric tractor-ploughing unit under complex soil conditions,leading to the proposal of an active control method for drive wheel torque and a joint control method for the traction force of the suspension system and the front-and rear-axle loads of a ***,the tractor is prototyped and assembled,and ploughing tests are carried *** ploughing results show that the active torque-distribution control method proposed in this study reduces the tractor slip by 14.83%and increases the traction efficiency by 10.28%compared with the average torquedistribution *** with the conventional traction control mode,the joint control method for traction and ballast proposed in this paper results in a 3.7%increase in traction efficiency,a 15.05%decrease in slip,and a 4.9%reduction in total drive motor energy *** study will help to improve the operation quality and traction efficiency of electric tractors in complex soil conditions.

关键词： Electric tractor Ploughing unit Torque distribution Active ballast Traction performance

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Geological conditions and reservoir characteristics of various shales in major shalehosted regions of China

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China Geology 2024年第1期7卷 138-149页

作者： Shu-jing Bao Tian-xu Guo Jin-tao Yin Wei-bin Liu Sheng-jian wang hao-han Li Zhi Zhou Shi-zhen Li Xiang-lin Chen The Key Laboratory of Unconventional Petroleum Geology China Geological SurveyMinistry of Natural Resources100083 BeijingChina Oil and Gas Survey China Geological Survey100083 BeijingChina Research Institute of Yanchang Petroleum(Group)CO.LTD 710076 Xi’anChina

China is home to shales of three facies:Marine shale,continental shale,and marine-continental transitional *** types of shale gas are associated with significantly different formation conditions and major controlling *** study compared the geological characteristics of various shales and analyzed the influences of different parameters on the formation and accumulation of shale *** general,shales in China’s several regions exhibit high total organic carbon(TOC)contents,which lays a sound material basis for shale gas *** strata generally show high degrees of thermal *** contrast,continental shales manifest low degrees of thermal evolution,necessitating focusing on areas with relatively high degrees of thermal evolution in the process of shale gas surveys for these *** shales of the Wufeng and Silurian formations constitute the most favorable shale gas reservoirs since they exhibit the highest porosity among the three types of *** shales are followed by those in the Niutitang and Longtan *** contrast,the shales of the Doushantuo,Yanchang,and Qingshankou formations manifest low ***,the shales of the Wufeng and Longmaxi formations exhibit high brittle mineral *** a low siliceous mineral content,the shales of the Doushantuo Formation feature a high carbonate mineral content,which can increase the shales’brittleness to some *** marine-continental transitional shales,where thin interbeds of tight sandstone with unequal thicknesses are generally found,it is recommended that fracturing combined with drainage of multiple sets of lithologic strata should be employed to enhance their shale gas production.

关键词： Shale gas Marine shale Continental shale Marine-continental transitional shale Neoproterozoic-Cretaceous strata Geological conditions Reservoir characteristics Petroleum geological survey engineering

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Taurine attenuates activation of hepatic stellate cells by inhibiting autophagy and inducing ferroptosis

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World Journal of Gastroenterology 2024年第15期30卷 2143-2154页

作者： Sen Li Qian-Jun Ren Can-hao Xie Yang Cui Li-Tao Xu Yi-Dan wang Su Li Xing-Qiu Liang bin Wen Ming-Kun Liang Xiao-Fang Zhao Department of Basic Science Guangxi University of Chinese MedicineNanning 541100Guangxi Zhuang Autonomous RegionChina Department of Science and Technology Ruikang Hospital Affiliated to Guangxi University of Chinese MedicineNanning 541100Guangxi Zhuang Autonomous RegionChina Traditional Chinese Medicine Specialty Office Ruikang Hospital Affiliated to Guangxi University of Chinese MedicineNanning 541100Guangxi Zhuang Autonomous RegionChina

BACKGROUND Liver fibrosis is a compensatory response during the tissue repair process in chronic liver injury,and finally leads to liver cirrhosis or even hepatocellular *** pathogenesis of hepatic fibrosis is associated with the progressive accumulation of activated hepatic stellate cells(HSCs),which can transdiffer-entiate into myofibroblasts to produce an excess of the extracellular matrix(ECM).Myofibroblasts are the main source of the excessive ECM responsible for hepatic ***,activated hepatic stellate cells(aHSCs),the principal ECM producing cells in the injured liver,are a promising therapeutic target for the treatment of hepatic *** To explore the effect of taurine on aHSC proliferation and the mechanisms *** Human HSCs(LX-2)were randomly divided into five groups:Normal control group,platelet-derived growth factor-BB(PDGF-BB)(20 ng/mL)treated group,mmol/L,respectively)with PDGF-BB(20 ng/mL)treated *** Counting Kit-8 method was performed to evaluate the effect of taurine on the viability of ***-linked immunosorbent assay was used to estimate the effect of taurine on the levels of reactive oxygen species(ROS),malondialdehyde,glutathione,and iron *** electron microscopy was applied to observe the effect of taurine on the autophagosomes and ferroptosis features in *** real-time polymerase chain reaction and Western blot analysis were performed to detect the effect of taurine on the expression ofα-SMA,Collagen I,Fibronectin 1,LC3B,ATG5,Beclin 1,PTGS2,SLC7A11,and *** Taurine promoted the death of aHSCs and reduced the deposition of the *** with taurine could alleviate autophagy in HSCs to inhibit their activation,by decreasing autophagosome formation,downregulating LC3B and Beclin 1 protein expression,and upregulating p62 protein ***,treatment with taurine triggered ferroptosis and ferritinophagy to eliminate aHSCs characterized b

关键词： Hepatic stellate cells Autophagy Ferroptosis Molecular docking Taurine

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Segregation of Mg-6Gd alloy under natural convection:From macro solute distribution to micro dendrite growth

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China Foundry 2024年第5期21卷 613-624页

作者： Hong-xu Chen Ang Zhang hao Li Yu Gao Yu-hong Cui Guang-sheng Huang bin Jiang Fu-sheng Pan National Engineering Research Center for Magnesium Alloys National Key Laboratory of Advanced Casting TechnologiesCollege of Materials Science and EngineeringChongqing UniversityChongqing 400044China

Segregation is a serious defect in alloy ingots which severely deteriorates materials *** segregation defect in Mg-6Gd alloy is studied by coupling macro thermal-solutal-convection transport and micro dendrite *** macroscopic fluid dynamics and mass transfer equations are resolved to forecast the segregation behavior under conditions of continuous temperature variation during the solidification *** numerical model is validated by testing double-diffusive natural convection in a closed square cavity.A phase field model is then applied to simulate the micro dendrite growth,using macro undercooling and liquid flow velocity as boundary *** show that the multiscale segregation behavior,including macro solute distribution and micro dendritic morphology,is strongly dependent on the temperature condition and the liquid convection,which provides guidance for reducing and eliminating the segregation defect.

关键词： magnesium alloy segregation numerical simulation phase-field simulation multiscale

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Establishment of predictive models and determinants of preoperative gastric retention in endoscopic retrograde cholangiopancreatography

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World Journal of Gastrointestinal Surgery 2024年第8期16卷 2574-2582页

作者： Ying Jia hao-Jun Wu Tang Li Jia-bin Liu Ling Fang Zi-Ming Liu Department of Thyroid Surgery West China HospitalSichuan UniversityChengdu 610041Sichuan ProvinceChina Division of Biliary Tract Surgery Department of General SurgeryWest China HospitalSichuan UniversityChengdu 610041Sichuan ProvinceChina Division of General Surgery West China Hospital-Chengdu Shangjin NanfuWest China HospitalChengdu 611730Sichuan ProvinceChina

BACKGROUND Study on influencing factors of gastric retention before endoscopic retrograde cholangiopancreatography(ERCP)background:With the wide application of ERCP,the risk of preoperative gastric retention affects the smooth progress of the *** study found that female,biliary and pancreatic malignant tumor,digestive tract obstruction and other factors are closely related to gastric retention,so the establishment of predictive model is very important to reduce the risk of *** A retrospective analysis was conducted on 190 patients admitted to our hospital for ERCP preparation between January 2020 and February *** baseline clinical data were collected using an electronic medical record *** were randomly matched in a 1:4 ratio with data from 190 patients during the same period to establish a validation group(n=38)and a modeling group(n=152).Patients in the modeling group were divided into the gastric retention group(n=52)and non-gastric retention group(n=100)based on whether gastric retention occurred *** data of patients in the validation group and identify factors influencing preoperative gastric retention in ERCP patients.A predictive model for preoperative gastric retention in ERCP patients was constructed,and calibration curves were used for *** receiver operating characteristic(ROC)curve was analyzed to evaluate the predictive value of the *** We found no statistically significant difference in general data between the validation group and modeling group(P>0.05).The comparison of age,body mass index,hypertension,and diabetes between the two groups showed no statistically significant difference(P>0.05).However,we noted statistically significant differences in gender,primary disease,jaundice,opioid use,and gastrointestinal obstruction between the two groups(P<0.05).Mul-tivariate logistic regression analysis showed that gender,primary disease,jaundice,opioid use,and gastrointestina

关键词： Cholangiopancreatography Gastric retention Influencing factors Predictive model Endoscope

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