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NUMERICAL SIMULATION OF THE ENERGY DISSIPATION CHARACTERISTICS IN STILlinG BASIN OF MULTI-HORIZONTAL SUBMERGED JETS

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Journal of Hydrodynamics 2010年第5期22卷 732-741页

作者： CHEN Jian-gang ZHANG Jian-min xu Wei-lin wang Yu-rong State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065 China

3-D numerical simulation was carried out for the water flow in a stilling basin with multi-horizontal submerged jets by using two different turbulence models, namely, the VOF RNG k-ε and Mixture RNG k-ε turbulence models. The calculated water depth, velocity profile and pressure distribution are in good agreement with the data obtained in experiments. It indicates that the numerical simulation can effectively be used to study the water flow movement and the energy dissipation mechanism. The numerical simulation results show that the turbulent kinetic energy distribution obtained by using the Mixture turbulence model covers a region about 18% larger than that calculated by using the VOF turbulence model, and is in better agreement with the actual situation. Furthermore, the Mixture turbulence model is better than the VOF turbulence model in calculating the air entrainment.

关键词： multi-horizontal submerged jets numerical simulation VOF method Mixture method hydraulic characteristics stilling basin

HYDRAULIC CHARACTERISTICS OF PLUG ENERGY DISSIPATER IN FLOOD DISCHARGE TUNNEL

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Journal of Hydrodynamics 2009年第6期21卷 799-806页

作者： TIAN Zhong xu Wei-lin wang Wei LIU Shan-Jun State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065 China

The hydraulic characteristics of three types of plugs, namely, the single plug, the stepped plug and the gradually contracted plug were studied by means of experimental and numerical simulations. Main research findings are as follows. For the single plug, the pressure recovery lengths inside and after the plug range from 0.63-1.05 times and 2.02-2.84 times of the tunnel diameter, respectively. For the stepped plug, the lengths are 0.24-0.32 times and 1.62-2.84 times of the tunnel diameter, respectively. The best ratio of the inlet diameter to the outlet diameter of the gradually contracted plug can be expressed by a linear function. The relationship between the head loss coefficient and the area contraction ratio is obtained. The incipient cavitation numbers of different plugs are experimentally and numerically determined, and the incipient cavitation numbers are expressed by a formula. Model experiment with scale of 1：50 was carried out on a pressure tunnel with three-stage gradually contracted plugs. The results show that this type of energy dissipater is suitable for spill tunnels of high head （nearly 200 m） and large flow rate （nearly 2500 m^3/s）.

关键词： plug incipient cavitation number energy dissipater CFD

SCALE EFFECTS OF AIR-WATER FLOWS IN STILlinG BASIN OF MULTI-HORIZONTAL SUBMERGED JETS

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Journal of Hydrodynamics 2010年第6期22卷 788-795页

作者： CHEN Jian-gang ZHANG Jian-min xu Wei-lin wang Yu-rong State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065China

A series of experiments were carried out on multi-horizontal submerged jets with four different model scales of 1：36, 1：57, 1：80, 1：200. In routine tests, scale effects have to be considered, due to complex vortex structure and strong air entrainment in stilling basin. Our focus was laid on measuring and analyzing the time-averaged pressure distribution, water depth and closed-to-bed velocity in the stilling basin of multi-horizontal submerged jets. The experiments results show that the model scale has but a slight effect on the time-averaged hydraulic characteristics in the stilling basin of multi-horizontal submerged jets, which indicates that the results of time-averaged hydraulic characteristics for a normal pressure model are reliable. However, the scale effects of air entrainment, fluctuation pressure and vortex structure call for further investigations in order to make the results of experiments serve as scientific references for practical engineering.

关键词： multi-horizontal submerged jets Xiangjiaba hydropower station scale effects experimental investigation hydraulic characteristics

THREE-DIMENSIONAL NUMERICAL SIMULATION OF AERATED FLOWS DOWNSTREAM SUDDEN FALL AERATOR EXPANSION-IN A TUNNEL

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Journal of Hydrodynamics 2011年第1期23卷 71-80页

作者： ZHANG Jian-min CHEN Jian-gang xu Wei-lin wang Yu-rong LI Gui-ji State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065China

Air entrainment is known to be one of efficient and inexpensive methods to prevent cavitation damages in hydropower *** shape of sudden expansion-fall is used as a common device for mitigating cavitation *** complex flow patterns with cavitation are numerically simulated by using the realizable k-εturbulence model and the air-water mixture *** calculated results are compared well with the experimental results as well as those obtained with the k-εturbulence model with the Volume Of Fluid（VOF）*** calculated results agree well with the experimental data for the aeration cavity and wall ***,the air concentration near sidewall is simulated by a mixture *** is found that the mixture turbulence model is superior to the VOF turbulence model.

关键词： sudden expansion-fall aerator RNG k-εturbulence model realizable k-εturbulence model Volume Of Fluid (VOF)method air-water Mixture turbulence model numerical simulation

HYDRODYNAMIC UPLIFT FORCE AND STABILITY OF ARCIFORM PLUNGE POOL

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Journal of Hydrodynamics 2002年第3期14卷 8-12页

作者： xu, Wei-lin wang, Wei Liu, Shan-Jun Qu, Jing-xue Diao, Ming-Jun Hydraulics Lab. of High Speed Flows Sichuan Univ. Chengdu 610065 China

Compared with general trapeziform plunge pools, an arciform plunge pool has its advantages, e.g. less excavate quantity, higher stability, etc. In this paper, the hydrodynamic pressure distribution on the soleplate of the arciform plunge pool is measured under a relatively dangerous condition of operation. The result is helpful to the design of the arciform plunge pool. The result also shows that the difference between the maximum and the minimum pressures on the upward surface of the soleplate may cause an additional uplift force on the soleplate under certain condition and should be taken into consideration in the uplift force calculation of the soleplate. The scour experiment verifies the higher stability of the arciform plunge pool.

关键词： Energy dissipators Hydrodynamics Pressure distribution Pressure measurement Stability Uplift pressure

SCALE EFFECT OF I MPINGING PRESSURE CAUSED BY SUBMERGED JET

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Journal of Hydrodynamics 2005年第4期17卷 478-482页

作者： TIAN Zhong xu Wei-lin wang Wei LIU Shan-jun DONG Jian-wei State Key Hydraulics Laboratory of High Speed Flows Sichuan University Chengdu 610065 China Military Oil Supply Engineering Department Logistical Engineering University Chongqing 400016China

The characteristics of the impinging pressure at the jet equipment where the maximum jet velocity can reach 50m/s were studied. By comparing the impinging pressure with the one measured at the low velocity conditions, two conclusions of the scale effect are drawn： firstly, the velocity attenuation degree is smaller than that of low velocity jet, and secondly, the relative impinging width is narrower than that of low-velocity jet. The reasons of the scale effect of the impinging pressure were elucidated through numerical simulation.

关键词： scale effect impinging pressure high-velocity jet numerical simulation

Role of Caspase and MMPs in Amniochorionic during PROM

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Journal of Reproduction and Contraception 2005年第4期16卷 219-224页

作者： Jun xu Hong-lin wang Department of Obstetric and Gynecology The Eighth People＇s Hospital of Shanghai Shanghai 200233 China

Objective To study the role of cysteine aspartic acid-specific protease-3 （caspase-3）, matrix metalloproteinase-2 （MMP-2） and tissue inhibitor of matrix metallo proteinase- 2 （TIMP-2） in human amniochorionic membranes during premature rupture of human fetal membranes （PROM）. Methods Amniochorionic membranes were collected from the following groups of women： women with spontaneous PROM （n =8）, women with normal labor in term after vaginal delivery（n=8） and women undergoing elective repeat cesarean section （C-section） before the onset of labor and who had no complications of pregnancy （n=8）. Caspase-3 peptides were studies with use of immunohistochemistry. Messenger ribonucleic acid （mRNA） expression for MMP-2 and its specific inhibitors TIMP-2 was studied with use of reverse transcriptase-polymerase chain reaction （RT-PCR）. Results 1） The expressions of Caspase-3 peptides were 62.86 ± 3.83% in PROM group, 42.33 ± 2.99% in vaginal delivery group, and 20.97±2.94% in C- section group. There were statistically significant changes among the three groups （P〈0.05）. lmmunohistochemistry demonstrated the presence of Caspase-3 in the amniotic epithelial cells and chorionic cytotrophoblast cells. 2） The expressions of MMP-2 were 84. 92 ± 3.68% in PROM group, 32.65 ± 2.34% in vaginal delivery group, and 30. 65 ± 2. 77% in C-section group. There were statistically significant changes between PROM and C-section group （P〈0. 05）. 3） The expressions of TIMP-2 were 42. O1 ± 12.17% in PROM group, 73.01 ± 14.82% in vaginal delivery group, and 88.47 ± 6.51% in C- section group. There were statistically significant changes among the three groups （p〈0.05）. Conclusion Caspase-3 gene expressed more in PROM than in comparative group, which caused human fetal membranes cell apoptosis increased. The expression MMP-2 increased and TIMP-2 dropped in PROM, which can increase the ECM decomposing. Cell apoptosis increased and extra cellular matrix degradation dropped, which may cause weakening

关键词： PROM amniochorion Caspase-3 MMP-2 TIMP-2

Association between composite dietary antioxidant index and stroke among individuals with diabetes

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World Journal of Diabetes 2024年第8期15卷 1742-1752页

作者： Hong-Qiang Zhang Jie Shi Tong Yue Jia-Hao Weng xu-lin wang Hao wang Xiao-Yu Su xue-Ying Zheng Si-Hui Luo Yu Ding Chao-Fan wang Department of Cardiology Centre for Leading Medicine and Advanced Technologies of IHMThe First Affiliated Hospital of USTCDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefei 230001Anhui ProvinceChina Department of Endocrinology Centre for Leading Medicine and Advanced Technologies of IHMThe First Affiliated Hospital of USTCDivision of Life Sciences and MedicineUniversity of Science and Technology of ChinaHefei 230001Anhui ProvinceChina Graduate School Bengbu Medical CollegeBengbu 233030Anhui ProvinceChina Department of Endocrinology and Metabolism The Third Affiliated Hospital of Sun Yat-sen UniversityGuangdong Provincial Key Laboratory of DiabetologyGuangzhou 510630Guangdong ProvinceChina

BACKGROUND Recent research has underscored the potentially protective role of dietary antioxidants against chronic conditions,such as cardiovascular diseases and *** composite dietary antioxidant index(CDAI),which reflects the overall intake of key dietary antioxidants,has been identified as a crucial metric for exploring this *** previous research has shown a negative correlation between CDAI levels and stroke risk in prediabetic individuals,there remains a substantial gap in understanding this association among individuals with diabetes,who are at an inherently greater risk for cerebrovascular *** To investigate the association between CDAI and stroke risk in individuals with *** Using a cross-sectional study design,this investigation analyzed data from the National Health and Nutrition Examination Survey spanning from 2003 to 2018 that included 6735 participants aged over 20 years with *** CDAI was calculated from 24-h dietary recalls to assess intake of key antioxidants:Vitamins A,C,and E;carotenoids;selenium;and *** logistic regression and restricted cubic spline analysis were used to rigorously examine the relationship between CDAI and stroke *** The participant cohort,with an average age of 59.5 years and a slight male majority,reflected the broader demographic characteristics of individuals with *** analysis revealed a strong inverse relationship between CDAI levels and stroke ***,those in the highest quintile of CDAI demonstrated a 43%lower prevalence of stroke compared to those in the lowest quintile,even after adjustments for various *** finding not only highlights the negative association between CDAI and stroke risk but also underscores the significant potential of antioxidant-rich diets in reducing stroke prevalence among patients with *** Our findings suggested that CDAI was inversely associated with stroke prevalence among pa

关键词： Stroke Diabetes Composite dietary antioxidant index National Health and Nutrition Examination Survey Crosssectional study

Pyroptosis,ferroptosis,and autophagy in spinal cord injury:regulatory mechanisms and therapeutic targets

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Neural Regeneration Research 2025年第10期20卷 2787-2806页

作者： Qingcong Zheng Du wang Rongjie lin Weihong xu Department of Spinal Surgery the First Affiliated Hospital of Fujian Medical UniversityFuzhouFujian ProvinceChina Arthritis Clinical and Research Center Peking University People’s HospitalBeijingChina Department of Orthopedic Surgery Fujian Medical University Union HospitalFuzhouFujian ProvinceChina

Regulated cell death is a form of cell death that is actively controlled by *** studies have shown that regulated cell death plays a key role after spinal cord *** and ferroptosis are newly discovered types of regulated cell deaths that have been shown to exacerbate inflammation and lead to cell death in damaged spinal ***,a complex form of cell death that is interconnected with various regulated cell death mechanisms,has garnered significant attention in the study of spinal cord *** injury triggers not only cell death but also cellular survival *** signaling pathways play pivotal roles in influencing the processes of both deterioration and repair in spinal cord injury by regulating pyroptosis,ferroptosis,and ***,this review aims to comprehensively examine the mechanisms underlying regulated cell deaths,the signaling pathways that modulate these mechanisms,and the potential therapeutic targets for spinal cord *** analysis suggests that targeting the common regulatory signaling pathways of different regulated cell deaths could be a promising strategy to promote cell survival and enhance the repair of spinal cord ***,a holistic approach that incorporates multiple regulated cell deaths and their regulatory pathways presents a promising multi-target therapeutic strategy for the management of spinal cord injury.

关键词： autophagy cell death ferroptosis inflammation pathological mechanisms pyroptosis regulated cell death regulatory pathways spinal cord injury therapeutic targets