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Physics of cavitation near particles

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Journal of Hydrodynamics 2024年第1期36卷 102-118页

作者： Jia-xin Yu Xiao-yu Wang jun-wei Shen Jin-sen Hu xiang-qing Zhang Da-qing He Yu-ning Zhang Key Laboratory of Power Station Energy Transfer Conversion and System(Ministry of Education) School of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBeijing102206China

The combined effect of cavitation and silt abrasion presents a great challenge and threat to secure the operation and the efficiency of hydraulic machineries working in sediment-laden *** present paper critically reviews the current research progress on the interaction mechanisms of the bubbles and the ***,the analytical models including boundary treatment methods for predicting the jet dynamics of the bubble collapse near particles are ***,the bubble collapsing dynamics,jet dynamics and shock wave characteristics near particles are revealed both experimentally and ***,the bubble-particle-wall system is investigated with a focus on microjets.

关键词： Cavitation bubble particle jet shock wave

Effect of Wave Nonlinearity on the Instantaneous Seabed Liquefaction

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China Ocean Engineering 2024年第1期38卷 93-103页

作者： WANG Zhao-jun SUI Ti-ti ZHANG Chi PAN jun-ning Key Laboratory of Port Waterway and Sedimentation Engineering of the Ministry of TransportNanjing Hydraulic Research InstituteNanjing 210024China Key Laboratory of Coastal Disaster and Protection(Hohai University) Ministry of EducationNanjing 210098China The National Key Laboratory of Water Disaster Prevention Nanjing 210098China

The nonlinear variation of wave is commonly seen in nearshore area,and the resulting seabed response and liquefaction are of high concern to coastal *** this study,an analytical formula considering the nonlinear wave skewness and asymmetry is adopted to provide wave pressure on the seabed *** liquefaction depth attenuation coefficient and width growth coefficient are defined to quantitatively characterize the nonlinear effect of wave on seabed *** on the 2D full dynamic model of wave-induced seabed response,a detailed parametric study is carried out in order to evaluate the influence of the nonlinear variation of wave loadings on seabed ***,new empirical prediction formulas are proposed to fast predict the maximum liquefaction under nonlinear *** indicate that(1)Due to the influence of wave nonlinearity,the vertical transmission of negative pore water pressure in the seabed is hindered,and therefore,the amplitude decreases significantly.(2)In general,with the increase of wave nonlinearity,the liquefaction depth of seabed decreases *** under asymmetric and skewed wave loading,the attenuation of maximum seabed liquefaction depth is the most significant among all the nonlinear wave ***,highly skewed wave can cause the liquefaction depth of seabed greater than that under linear wave.(3)The asymmetry of wave pressure leads to the increase of liquefaction width,whereas the influence of skewedness is not significant.(4)Compared with the nonlinear waveform,seabed liquefaction is more sensitive to the variation of nonlinear degree of wave loading.

关键词： nonlinear wave seabed response seabed liquefaction numerical simulation liquefaction prediction

A robust viscoelastic surfactant tolerating 20% HCl up to 150℃ for oil well stimulation

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Petroleum Science 2024年第3期21卷 1865-1874页

作者： Ji Wang ning Qi Hong-Yao Yin Yu-jun Feng Polymer Research Institute State Key Laboratory of Polymer Materials Engineering Sichuan University Tianfu Yongxing Laboratory New Theory and Technology of CO School of Petroleum Engineering China University of Petroleum (East China)

Viscoelastic surfactants（VES） are often used as viscous diverters in acidizing stimulation to prolong the acid consumption time and maximize zonal coverage of the acid for improving well ***, the ceiling temperature of commercial VES cannot exceed 120℃ in practical use because of the poor thermal stability and fragile molecular structure, hindering their implementation in hightemperature oil reservoirs, i.e., ≥150℃. Here we synthesized a novel C22-tailed diamine, N-erucaminopropyl-N,N-dimethylamine（EDPA）, and examined comparatively its rheological behavior, assemblies morphology and molecular stability in 20 wt% HCl with a commercial VES, erucyl dimethyl amidopropyl betaine（EDAB）. The feasibility of EDPA for acidizing stimulation was assessed by acid etching of carbonate rock with its HCl solution at 150℃. Rheological results showed that the 2.5 wt% EDPA—20 wt%HCl solution maintains stable viscosity of 90 m Pa s at 150℃ for 60 min, while that of 2.0 wt% EDAB HCl solution is just 1 m Pa s under identical conditions.1H NMR spectra and cryo-TEM observations revealed that the chemical structure and self-assembled architectures of EDPA remained intact in such context,but the EDAB suffered from degradation due to the hydrolysis of the amide group, accounting for the poor heat-resistance and acid-tolerance. The reaction rate of 2.5 wt% EDPA HCl solution with carbonate rock was one order of magnitude lower than that of 20 wt% HCl solution at 150℃, underpinning the potential of EDPA to be used in the high-temperature reservoirs acidizing. This work improved the thermal tolerance of VES in highly concentrated HCl solution, paving a feasible way for the acidization of high-temperature reservoir environments（～150℃）.

关键词： Viscoelastic surfactants Thermal stability Self-diverting acid Wormlike micelles Acidizing stimulation

Visible light cross-linking and bioactive peptides loaded integrated hydrogel with sequential release to accelerate wound healing complicated by bacterial infection

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Nano Research 2024年第3期17卷 1737-1747页

作者： Guiyan Wang ning Yuan jun Zhang Man Qin Suwei Dong Yuguang Wang Department of Pediatric Dentistry Peking University School and Hospital of StomatologyBeijing 100081China State Key Laboratory of Natural and Biomimetic Drugs Chemical Biology Centerand School of Pharmaceutical SciencesPeking UniversityBeijing 100191China Department of Prosthodontics Peking University School and Hospital of StomatologyBeijing 100081China

The effective management of bacterial infections that are resistant to multiple drugs remains a substantial clinical *** eradication of drug-resistant bacteria and subsequent promotion of angiogenesis are imperative for the regeneration of the infected ***,a novel and facile peptide containing injectable hydrogel with sustained antibacterial and angiogenic capabilities is *** antibacterial peptide that consists of 11 residues(CM11,WKLFKKILKVL)is loaded onto acrylate-modified gelatin through charge interactions.A vascular endothelial growth factor mimetic peptide KLT(KLTWQELYQLKYKGI)with a GCG(Gly-Cys-Gly)modification at the N-terminal is covalently coupled through a visible light-induced thiol-ene *** this reaction,the acrylate gelatin undergoes cross-linkage within *** on the physical/chemical double crosslinking strategy,the bioactive peptides achieve sustained and sequential *** results show that the hydrogel significantly inhibits methicillin-resistant Staphylococcus aureus(MRSA)growth through the rapid release of CM11 peptides at early stage;it forms obvious growth inhibition zones against pathogenic bacterial ***,cell counting kit-8 assay and scratch test confirm that the CM11/KLT-functionalized hydrogels promote cell proliferation and migration through the later release of KLT *** a mouse skin wound infected with self-luminous MRSA,the CM11/KLT-functionalized hydrogels enhance wound healing,with rapidly bacterial infection reduction,lower expression of inflammatory factors,and neovascularization *** results suggest that the rationally designed,sustained and sequential release CM11/KLT-functionalized hydrogels have huge potential in promoting the healing of multi-drug resistant bacterial infected wounds.

关键词： antimicrobial peptide vascular endothelial growth factor(VEGF)mimetic peptide sequential release visible-light crosslinking hydrogel wound therapy

Effects of soil metal(loid)s pollution on microbial activities and environmental risks in an abandoned chemical smelting site

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Journal of Environmental Sciences 2024年第9期143卷 60-70页

作者： Hao Li jun Yao Jianli Liu ning Min Geoffrey Sunahara Dongyang Men Robert Duran School of Water Resources and Environment Research Center of Environmental Science and EngineeringChina University of Geosciences(Beijing)Beijing 100083China Department of Natural Resource Sciences McGill University21111Lakeshore DriveSte-Anne-de-BellevueQuebecH9X 3V9Canada Equipe Environnement et Microbiologie MELODY groupUniversitéde Pau et des Pays de l’AdourE2S-UPPAIPREM UMR CNRS 5254BP 115564013 Pau CedexFrance

Abandoned chemical smelting sites containing toxic substances can seriously threaten and pose a risk to the surrounding ecological *** samples were collected from different depths(0 to 13 m)and analyzed for metal(loid)s content and fractionation,as well as microbial *** potential ecological risk indices for the different soil depths(ordered from high to low)were:1 m(D-1)>surface(S-0)>5 m(D-5)>13 m(D-13)>9 m(D-9),ranging between 1840.65-13,089.62,and representing extremely high environmental risks,of which Cd(and probably not arsenic)contributed to the highest environmental risk.A modified combined pollution risk index(MCR)combining total content and mobile proportion of metal(loid)s,and relative toxicities,was used to evaluate the degree of contamination and potential environmental *** the near-surface samples(S-0 and D-1 layers),the MCR considered that As,Cd,Pb,Sb,and Zn achieved high and alarming degrees of contamination,whereas Fe,Mn,and Ti were negligible or low to moderate pollution *** microcalorimetry and enzymatic activity measurements of contaminated soil samples were used to assess the microbial metabolic activity *** analysis elucidated the relationship between metal(loid)s exchangeable fraction or content and microbial activity characteristics(p<0.05).The microbial metabolic activity in the D-1 layer was low presumably due to heavy metal *** activity indicators and microcalorimetric growth rate(k)measurements were considered sensitive indicators to reflect the soil microbial activities in abandoned chemical smelting sites.

关键词： Abandoned chemical smelting sites Microbial activities Modified combined pollution risk Microcalorimetry Enzymatic activities

Risk assessment of oil and gas investment environment in countries along the Belt and Road Initiative

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Petroleum Science 2024年第2期21卷 1429-1443页

作者： Bao-jun Tang Chang-Jing Ji Yu-Xian Zheng Kang-ning Liu Yi-Fei Ma jun-Yu Chen Center for Energy and Environmental Policy Research Beijing Institute of TechnologyBeijing100081China School of Management and Economics Beijing Institute of TechnologyBeijing100081China Collaborative Innovation Center of Electric Vehicles in Beijing BeijingChina Sustainable Development Research Institute for Economy and Society of Beijing BeijingChina Institute of Carbon Neutrality ShanghaiTech UniversityShanghai201210China

With the implementation of the Belt and Road Initiative, China is deepening its cooperation in oil and gas resources with countries along the Initiative. In order to better mitigate risks and enhance the safety of investments, it is of significant importance to research the oil and gas investment environment in these countries for China's overseas investment macro-layout. This paper proposes an indicator system including 27 indicators from 6 dimensions. On this basis, game theory models combined with global entropy method and analytic hierarchy process are applied to determine the combined weights, and the TOPSIS-GRA model is utilized to assess the risks of oil and gas investment in 76 countries along the Initiative from 2014 to 2021. Finally, the GM(1,1) model is employed to predict risk values for 2022-2025. In conclusion, oil and gas resources and political factors have the greatest impact on investment environment risk, and 12 countries with greater investment potential are selected through cluster analysis in conjunction with the predicted results. The research findings may provide scientific decisionmaking recommendations for the Chinese government and oil enterprises to strengthen oil and gas investment cooperation with countries along the Belt and Road Initiative.

关键词： Belt and Road Initiative Oil and Gas Investment Risk assessment

Outcomes of endoscopic sclerotherapy for jejunal varices at the site of choledochojejunostomy (with video): Three case reports

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World Journal of Gastroenterology 2024年第14期30卷 2059-2067页

作者： jun Liu Peng Wang Li-Mei Wang Jing Guo ning Zhong Department of Gastroenterology Qilu Hospital of Shandong UniversityJinan 250012Shandong ProvinceChina

BACKGROUND Hemorrhage associated with varices at the site of choledochojejunostomy is an unusual,difficult to treat,and often fatal manifestation of portal *** far,no treatment guidelines have been *** SUMMARY We reported three patients with jejunal varices at the site of choledochojejun-ostomy managed by endoscopic sclerotherapy with lauromacrogol/α-butyl cyanoacrylate injection at our institution between june 2021 and August *** reviewed all patient records,clinical presentation,endoscopic findings and treatment,outcomes and *** patients who underwent pancre-aticoduodenectomy with a Whipple anastomosis were examined using conven-tional upper gastrointestinal endoscopy for suspected hemorrhage from the afferent jejunal *** with stigmata of recent hemorrhage or active he-morrhage were observed around the choledochojejunostomy site in all three *** injection of lauromacrogol/α-butyl cyanoacrylate was carried out at jejunal varices for all three *** bleeding ceased and patency was observed for 26 and 2 months in two *** one patient with multiorgan failure and internal environment disturbance,rebleeding occurred 1 month after endoscopic sclerotherapy,and despite a second endoscopic sclero-therapy,repeated episodes of bleeding and multiorgan failure resulted in eventual *** We conclude that endoscopic sclerotherapy with lauromacrogol/α-butyl cyanoac-rylate injection can be an easy,effective,safe and low-cost treatment option for jejunal varicose bleeding at the site of choledochojejunostomy.

关键词： Endoscopic sclerotherapy Jejunal varices Choledochojejunostomy Portal vein hypertension Case report

Active components of Dengzhan Shengmai ameliorate cognitive impairment by facilitating hippocampal long-term potentiation via the NMDA receptor-mediated Ca^(2+)/CaMKII pathway

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Journal of Pharmaceutical Analysis 2024年第3期14卷 435-438页

作者： Congyu Ma ning Sheng jun Wu Lulu Wang Jiandong Jiang Haibo Yu Jinlan Zhang State Key Laboratory of Bioactive Substance and Function of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing100050China Institute of Medicinal Biotechnology Chinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing100050China

Abnormal synaptic plasticity causes cognitive *** long-term potentiation(LTP)is a critical synaptic plasticity process[1].Rescuing impaired LTP is challenging;hence,novel agents are required for LTP *** medicine Dengzhan Shengmai(DzSM)has shown notable clinical efficacy against cognitive deficits[2].However,it remains unclear how DzSM modulates *** previous study[3]revealed the influence of DZSM on glutamatergic and GABAergic synapses following chronic cerebral hypoperfusion(CCH),which motivated us to assess how DzSM affects synaptic functions.

关键词： impaired impairment hence

Development of a Front End Array for Broadband Phased Array Receiver

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Research in Astronomy and Astrophysics 2024年第4期24卷 60-70页

作者： Kai Wang Liang Cao jun Ma Xue-Feng Duan Hao Yan Mao-Zheng Chen Yun-Wei ning Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 8300lChina University of the Chinese Academy of Sciences Beijing 100049China Xinjiang Key Laboratory of Microwave Technology Urumqi 830011China

The receiver is a signal receiving device placed at the focus of the *** order to improve the observation efficiency,the concept of phased array receiver has been proposed in recent years,which places a small phased array at the focal plane of the reflector,and flexible pattern and beam scanning functions can be achieved through a beamforming *** combined with the element multiplexing,all beams within the entire field of view can be observed simultaneously to achieve continuous sky *** article focuses on the front-end array of phased array receiver at 0.7-1.8 GHz for QiTai Telescope,and designs a Vivaldi antenna array of PCB structure with dual line *** polarization antenna is designed to arrange in a rectangle manner by 11×*** on the simulation results of the focal field,32,18,and eight elements were selected to form one beam at 0.7,1.25,and1.8 *** analog beamforming network was constructed,and the measured gains of axial beam under uniform weighting were 19.32,13.72,and 15.22 *** the beam scanning method of reflector antenna,the pattern test of different position element sets required for PAF beam scanning was carried out under independent *** pattern optimization at 1.25 GHz was carried out by weighting method of conjugate field *** with uniform weighting,the gain,sidelobe level,and main beam direction under conjugate field matching have been *** the above test and simulation results are slightly different,which is related to the passive array and laboratory testing condition,the relevant work has accumulated experience in the development of the front-end array for the phased array receiver,and has good guiding significance for future performance verification after the array is installed on the telescope.

关键词： telescopes instrumentation:detectors techniques:radar astronomy