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Health behavior outcomes in stroke survivors prescribed wearables for atrial fibrillation detection stratified by age
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作者 Joanne Mathew Jordy Mehawej +11 位作者 Ziyue Wang Taylor Orwig Eric Ding Andreas Filippaios Syed Naeem Edith Mensah Otabil Alex Hamel Kamran Noorishirazi IrinaRadu Jane Saczynski David D.McManus Khanh-Van Tran 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2024年第3期323-330,共8页
BACKGROUND Smartwatches have become readily accessible tools for detecting atrial fibrillation(AF).There remains limited data on how they affect psychosocial outcomes and engagement in older adults.We examine the heal... BACKGROUND Smartwatches have become readily accessible tools for detecting atrial fibrillation(AF).There remains limited data on how they affect psychosocial outcomes and engagement in older adults.We examine the health behavior outcomes of stroke survivors prescribed smartwatches for AF detection stratified by age.METHODS We analyzed data from the Pulsewatch study,a randomized controlled trial that enrolled patients(≥50 years)with a history of stroke or transient ischemic attack and CHA2DS2-VASc≥2.Intervention participants were equipped with a cardiac patch monitor and a smartwatch-app dyad,while control participants wore the cardiac patch monitor for up to 44 days.We evaluated health behavior parameters using standardized tools,including the Consumer Health Activation Index,the Generalized Anxiety Disorder questionnaire,the 12-Item Short Form Health Survey,and wear time of participants categorized into three age groups:Group 1(ages 50-60),Group 2(ages 61-69),and Group 3(ages 70-87).We performed statistical analysis using a mixedeffects repeated measures linear regression model to examine differences amongst age groups.RESULTS Comparative analysis between Groups 1,2 and 3 revealed no significant differences in anxiety,patient activation,perception of physical health and wear time.The use of smartwatch technology was associated with a decrease in perception of mental health for Group 2 compared to Group 1(β=-3.29,P=0.046).CONCLUSION Stroke survivors demonstrated a willingness to use smartwatches for AF monitoring.Importantly,among these study participants,the majority did not experience negative health behavior outcomes or decreased engagement as age increased. 展开更多
关键词 PRESCRIBED stratified WEAR
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Application Effect of Stratified Nursing Intervention for ICU Mechanically Ventilated Patients in the Context of Aspiration Risk Assessment
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作者 Caisu Qin Yong Gao +1 位作者 Yanchi Zheng Wenjuan Wang 《Journal of Clinical and Nursing Research》 2024年第6期226-231,共6页
Objective:To explore the application effect of stratified nursing intervention based on the background of misinspiration risk assessment in mechanically ventilated patients in intensive care unit(ICU).Methods:100 case... Objective:To explore the application effect of stratified nursing intervention based on the background of misinspiration risk assessment in mechanically ventilated patients in intensive care unit(ICU).Methods:100 cases of mechanically ventilated patients who were admitted to the ICU of our hospital from March 2022 to March 2023 were selected and divided into an observation group and a control group according to the random number table method,with 50 cases in each of the two groups.The control group was given routine care in ICU,and the observation group was given stratified nursing interventions based on the background of the risk of aspiration assessment on the basis of the control group,and both groups were cared for until they were transferred out of the ICU,and the mechanical ventilation time,ICU stay time,muscle strength score,complication rate,adherence,and satisfaction were observed and compared between the two groups.Results:The mechanical ventilation time and ICU stay time of the observation group were shorter than that of the control group after the intervention;the muscle strength score,compliance and satisfaction of the observation group were higher than that of the control group after the intervention;and the complication rate of the observation group was lower than that of the control group after the intervention,all of which were P<0.05.Conclusion:The application of stratified nursing intervention based on the background of misaspiration risk assessment in ICU mechanically ventilated patients can improve the patient's muscle strength,shorten the time of mechanical ventilation,promote the patient's recovery,reduce the occurrence of complications,and improve the patient's compliance and satisfaction. 展开更多
关键词 Mechanical ventilation Aspiration risk assessment stratified care Muscle strength COMPLICATION
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Predicting disease progression in cirrhotic patients after transjugular intrahepatic portosystemic shunt implantation:A sexstratified analysis 被引量:1
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作者 Qian Zhang Li Long +4 位作者 Hong-Lin Zhu Hong Peng Xin-Hua Luo Kang-Shun Zhu Rong-Pin Wang 《World Journal of Gastroenterology》 SCIE CAS 2023年第42期5768-5780,共13页
BACKGROUND Transjugular intrahepatic portosystemic shunt(TIPS)has been extensively used to treat portal hypertension-associated complications,including cirrhosis.The prediction of post-TIPS prognosis is important for ... BACKGROUND Transjugular intrahepatic portosystemic shunt(TIPS)has been extensively used to treat portal hypertension-associated complications,including cirrhosis.The prediction of post-TIPS prognosis is important for cirrhotic patients,as more aggressive liver transplantation is needed when the post-TIPS prognosis is poor.AIM To construct a nutrition-based model that could predict the disease progression of cirrhotic patients after TIPS implantation in a sex-dependent manner.METHODS This study retrospectively recruited cirrhotic patients undergoing TIPS implantation for analysis.Muscle quality was assessed by measuring the skeletal muscle index(SMI)by computed tomography.Multivariate Cox proportional hazard models were utilized to determine the association between SMI and disease progression in cirrhotic patients after TIPS implantation.RESULTS This study eventually included 186 cirrhotic patients receiving TIPS who were followed up for 30.5±18.8 mo.For male patients,the 30-mo survival rate was significantly lower and the probability of progressive events was higher(3.257-fold)in the low-level SMI group than in the high-level SMI group.According to the multivariate Cox analysis of male patients,SMI<32.8 was an independent risk factor for long-term adverse outcomes after TIPS implantation.A model was constructed,which involved creatinine,plasma ammonia,SMI,and acute-on-chronic liver failure and hepatic encephalopathy occurring within half a year after surgery.This model had an area under the receiver operating characteristic curve of 0.852,sensitivity of 0.926,and specificity of 0.652.According to the results of the DeLong test,this model outperformed other models(Child-Turcotte-Pugh,Model for End-Stage Liver Disease,and Freiburg index of post-TIPS survival)(P<0.05).CONCLUSION SMI is strongly associated with poor long-term outcomes in male patients with cirrhosis who underwent TIPS implantation. 展开更多
关键词 Transjugular intrahepatic portosystemic shunt Skeletal muscle index NUTRITION CIRRHOSIS Sex stratified Prognosis
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Combined effect of subsurface dam and layered heterogeneity on groundwater flow and salinity distribution in stratified coastal aquifers
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作者 Chao Gao Jun Kong +2 位作者 Jun Wang Tong Zhou Yuncheng Wen 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第8期49-60,共12页
In this paper,for the first time,we investigated the combined effect of subsurface dams and a typical stratified aquifer(two high-permeability layers with a low-permeability layer between them)on groundwater flow and ... In this paper,for the first time,we investigated the combined effect of subsurface dams and a typical stratified aquifer(two high-permeability layers with a low-permeability layer between them)on groundwater flow and salinity distribution in a tidally influenced coastal unconfined aquifer.Subsurface dams can inhibit the invasion of saltwater,and the low-permeability layer(LPL)and tide action can increase the effect of subsurface dams and the removal rate of residual saltwater.Through sensitivity analysis,it was discovered that shifting the dam location towards the inland resulted in a reduction in the effective heights of the dam.The upper saline plume contracted with increasing dam height,and the upper boundary of LPL was moved to shallower regions.And the natural removal time increased significantly with increasing dam height and the bottom boundary of LPL was moved to deeper regions.In addition,if the dam location was close to the sea boundary and the bottom boundary of LPL was moved to deeper regions,we could increase the subsurface dam height to reduce the risks of control of saltwater intrusion.This study provides us a comprehensive understanding of the complex hydrodynamics of saltwater intrusion and provides guides for the design of subsurface dams aimed at saltwater intrusion control in stratified coastal aquifers. 展开更多
关键词 stratified subsurface dams saltwater intrusion residual saltwater natural removal
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Non-symmetric distributions of solids deposition for solid-water stratified flow in deviated tubing strings
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作者 Xin-Fu Liu Chun-Hua Liu +7 位作者 Zhong-Xian Hao Ying Zheng Kai Zhang Jian-Feng Wang Song-Bo Wei Ai-Gang Hao Jun-Ling Tao Hui Cheng 《Petroleum Science》 SCIE EI CSCD 2023年第5期3048-3061,共14页
Dynamic performance on solids flow with water in deviated tubing is essential for the reliability of pump and normal operation of horizontal and directional wells.Compared with coal-water flow in vertical tubing and s... Dynamic performance on solids flow with water in deviated tubing is essential for the reliability of pump and normal operation of horizontal and directional wells.Compared with coal-water flow in vertical tubing and sand-oil flow with high production in deviated tubing,solids deposition with water shows obvious non-symmetric distributions in deviated tubing from simulations and experiments.The mathematical model of two phase flow was developed under coupling conditions of deviated tubing,low flow rate and viscosity based on the kinetic theory of granular flow and first-order discrete scheme.The results show that solid-water stratified flow in deviated tubing can be divided into two zones of suspension bed and the moving bed throughout the flow field.The solid flowing velocity with water is negative and particles slide down at the bottom of moving bed zone.The process of solids flow with water in deviated tubing will produce pressure loss and consume the kinetic energy.The thickness of deposited layer and the flowing velocity of solids flow downward with water at the moving bed zone enhance with the decreased inlet flow rate and the increased particle size,tubing inside diameter(ID)and inclination angle.Solids are easier into suspension from the upper part of moving bed zone to suspension bed zone and more solid particles flow with water towards the tubing outlet with the increase of inlet flowing velocity.The decision is made to reduce the screen width,tubing ID and inclination angle to maintain to be greater than critical deposition velocity in order to prevent solids settling.And it provides the theoretical basis and technical reserves for solid control and offers an effective approach to enhance tubing cleaning in deviated strings. 展开更多
关键词 Deviated tubing stratified flow Solid deposition Critical velocity Prevent solids settling
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Wax deposition modeling in oil-water stratified pipe flow
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作者 Hui-Shu Liu Ji-Miao Duan +5 位作者 Jiang Li Jian Wang Hao Yan Ke-Yu Lin Ke-Cheng Gu Chang-Jun Li 《Petroleum Science》 SCIE EI CAS CSCD 2023年第1期526-539,共14页
Wax deposition in oil-water stratified flow is commonly encountered onshore and offshore oil production pipe systems,and typically reduces transportation capacity of oil.The accurate predicted model of wax deposition ... Wax deposition in oil-water stratified flow is commonly encountered onshore and offshore oil production pipe systems,and typically reduces transportation capacity of oil.The accurate predicted model of wax deposition has becomes an indispensable approach to design effective remediation strategies.However,a reliable mechanistic model for wax deposition prediction in oil-water two-phase stratified pipe flow is lacking to validate the deposition process.In this work,a three-dimensional(axial,radial,and angular)robust wax deposit model for oil-water stratified circular pipe flow was developed.The model of formation of a gel deposit based on the first principles of rheology was developed,associated with the results obtained from hydrodynamics and heat/mass transfer simulations.The predictions for wax deposition are found to compare satisfactorily with experimental data with two different oils for single phase and four different water cuts for oil-water stratified pipe flow.It can be seen from the wax gelation mechanism that an increase in water cut can help to reduce the wall/oil-deposit interface shear stress,thereby leading to an increase in the degree of gelation as well as the deposit rate.Furthermore,a local deposit analysis in the circumferential direction was conducted,for water cut 75%and total flow rate 5 m3/h,which provided insights to understand that the thickness on pipe wall was roughly uniformly distributed locates near the top of the pipe and the nearer the position gets close to two points,where the oil-water interface contacts the inner wall,the deposition thickness quickly dropped to 0.It was attributed to the fact that a roughly uniformly thickness far away from the oil-water interface contact the inner wall resulted in the slowly changes temperature along the circumferential pipe wall wetted by oil. 展开更多
关键词 Wax deposition Oil-water flow stratified flow Heat and mass transfer
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Laboratory investigation on damping characteristics of homogeneous and stratified soil-ash system
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作者 Amit Kumar Ram Supriya Mohanty 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第10期2757-2777,共21页
In this study,the damping responses of uniform soil,equi-proportional fly ash,and local soil as a single unit were investigated.The large-strain cyclic triaxial tests were performed for the specimen compacted at the d... In this study,the damping responses of uniform soil,equi-proportional fly ash,and local soil as a single unit were investigated.The large-strain cyclic triaxial tests were performed for the specimen compacted at the desired density(95%e99%of maximum dry density).The compacted specimens were tested under the loading frequency of 0.3e1 Hz with medium confinement of 70e100 kPa.Also,the unsymmetrical behavior of the hysteresis loop was analyzed using three different damping estimation approaches,i.e.symmetric hysteresis loop(SHL),asymmetric hysteresis loop(ASHL),and the modified American Society for Testing and Materials(ASTM)method.The outcome of the study shows for fly ash,local soil,and layered soil-ash,the ASHL technique has the highest damping value,followed by ASTM and then the SHL approach.The specimens prepared under high density and subjected to high confinement show low damping values.However,the specimens tested at high frequency exhibits high damping behavior.Similarly,the damping value of fly ash determined using the SHL and ASHL methods has a similar profile and reaches a maximum at 1%shear strain value before decreasing.The composite stratified deposit exhibits more dependency on relative compaction,confining pressure,and less on loading frequency.Based on the results,it is highly recommended to use the ASHL approach,especially under large strain conditions irrespective of soil type.The maximum damping ratio of stratified deposits is always in between the damping ratio of local soil and fly ash.The damping ratio of stratified soil and local soil is slightly larger than that of the other soils,although the damping ratio of fly ash is equivalent to that of the sand and clayey soil.These results may be helpful in the accurate determination of the damping properties of the layered soil-ash system that is required in the seismic response analysis. 展开更多
关键词 Homogeneous soil stratified soil-ash system Damping behavior Cyclic triaxial test Asymmetric hysteresis loop Model fitting
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Linear logistic regression with weight thresholding for flow regime classification of a stratified wake
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作者 Xinyi L.D.Huang Robert F.Kunz Xiang I.A.Yang 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2023年第2期120-127,共8页
A stratified wake has multiple flow regimes,and exhibits different behaviors in these regimes due to the competing physical effects of momentum and buoyancy.This work aims at automated classification of the weakly and... A stratified wake has multiple flow regimes,and exhibits different behaviors in these regimes due to the competing physical effects of momentum and buoyancy.This work aims at automated classification of the weakly and the strongly stratified turbulence regimes based on information available in a full Reynolds stress model.First,we generate a direct numerical simulation database with Reynolds numbers from 10,000 to 50,000 and Froude numbers from 2 to 50.Order(100)independent realizations of temporally evolving wakes are computed to get converged statistics.Second,we train a linear logistic regression classifier with weight thresholding for automated flow regime classification.The classifier is designed to identify the physics critical to classification.Trained against data at one flow condition,the classifier is found to generalize well to other Reynolds and Froude numbers.The results show that the physics governing wake evolution is universal,and that the classifier captures that physics. 展开更多
关键词 stratified wake CLASSIFICATION Supervised learning Full Reynolds stress modelling
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Heat and Mass Transfers in a Two-Phase Stratified Turbulent Fluid Flow in a Geothermal Pipe with Chemical Reaction
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作者 Eric M. Nyariki Mathew N. Kinyanjui Jeconia O. Abonyo 《Journal of Applied Mathematics and Physics》 2023年第2期484-513,共30页
This research focused on the study of heat and mass transfers in a two-phase stratified turbulent fluid flow in a geothermal pipe with chemical reaction. The derived non-linear partial differential equations governing... This research focused on the study of heat and mass transfers in a two-phase stratified turbulent fluid flow in a geothermal pipe with chemical reaction. The derived non-linear partial differential equations governing the flow were solved using the Finite Difference Method. The effects of various physical parameters on the concentration, skin friction, heat, and mass transfers have been determined. Analysis of the results obtained indicated that the coefficient of skin friction decreased with an increase in Reynolds number and solutal Grasholf number, the rate of heat transfer increased with an increase in Eckert number, Prandtl number, and angle of inclination, and the rate of mass transfer increased with increase in Reynolds number, Chemical reaction parameter and angle of inclination. The findings would be useful to engineers in designing and maintaining geothermal pipelines more effectively. 展开更多
关键词 TWO-PHASE Turbulence Non-Newtonian INCLINATION Heat Transfer Mass Transfer stratified
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Singularity-free Green's function for EM sources embedded in a stratified medium 被引量:3
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作者 翁爱华 刘云鹤 +1 位作者 殷长春 贾定宇 《Applied Geophysics》 SCIE CSCD 2016年第1期25-36,217,218,共14页
We present a method to unify the calculation of Green's functions for an electromagnetic(EM) transmitting source embedded in a homogeneous stratified medium.A virtual interface parallel to layer interfaces is intro... We present a method to unify the calculation of Green's functions for an electromagnetic(EM) transmitting source embedded in a homogeneous stratified medium.A virtual interface parallel to layer interfaces is introduced through the source location.The potentials for Green's function are derived by decomposing the partial wave solutions to Helmholtz's equations into upward and downward within boundaries.The amplitudes of the potentials in each stratum are obtained recursively from the initial amplitudes at the source level.The initial amplitudes are derived by coupling with the transmitting sources and following the discontinuity of the tangential electric and magnetic fields at the source interface.Only the initial terms are related to the transmitting sources and thus need to be modified for different transmitters,whereas the kernel connected with the stratified media stays unchanged.Hence,the present method can be easily applied to EM transmitting sources with little modification.The application of the proposed method to the marine controlled-source electromagnetic method(MCSEM) demonstrates its simplicity and flexibility. 展开更多
关键词 EM Marine EM Green's function stratified medium SINGULARITY
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Invasive stratified mucin-producing carcinoma (ISMC) of the uterinecervix: An analysis of 6 cases with distinctive clinicopathologicalfeatures
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作者 TING LAN SHENG QIN +3 位作者 XIAOJIN GONG PING ZHENG JIAXIN YAN YANG LIU 《BIOCELL》 SCIE 2021年第5期1313-1319,共7页
Invasive stratified mucin-producing carcinoma(ISMC)is a recently described histologic variant of high-risk human papillomavirus(HPV)-associated endocervical adenocarcinoma,as the putative invasive counterpart of the s... Invasive stratified mucin-producing carcinoma(ISMC)is a recently described histologic variant of high-risk human papillomavirus(HPV)-associated endocervical adenocarcinoma,as the putative invasive counterpart of the stratified mucin-producing intraepithelial lesion(SMILE).ISMC can display variable architectural patterns and usually coexists with other more conventional types of HPV-associated carcinomas,which makes diagnosis and differential diagnosis of ISMC is difficult for pathologists.Moreover,the prognosis of ISMC is still controversial.We analyzed 6 ISMCs with detailed pathological and clinical information.Intraepithelial lesion,including 1 high-grade squamous intraepithelial lesion and 1 SMILE,was found.Various architectures were observed(including nest,glandular,solid,trabecular,and single cell).Nuclear peripheral palisading,apoptotic bodies and mitoses,and variable cytoplasmic mucin vacuoles were seen in all of our cases.The predominance of neutrophils infiltration was seen in only 1 tumor.All the tumors infiltrated the cervical stroma in Silva pattern C manner.p63 and/or p40 was characteristically expressed in the peripheral cells in only 2 cases.High-risk HPV infection was observed in 3/3 detected cases.All the patients were alive during the follow-up time.Recognition of this infrequent tumor may help pathologists and oncologists for an accurate diagnosis and a better understanding of the clinicopathological behavior. 展开更多
关键词 Invasive stratified mucin-producing carcinoma ISMC stratified mucin-producing intraepithelial lesion SMILE Cervical carcinoma Human papillomavirus
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Likelihood Methods for Basic Stratified Sampling, with Application to Von Bertalanffy Growth Model Estimation
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作者 Nan Zheng Noel Cadigan 《Open Journal of Statistics》 2019年第6期623-642,共20页
This paper mainly addresses maximum likelihood estimation for a response-selective stratified sampling scheme, the basic stratified sampling (BSS), in which the maximum subsample size in each stratum is fixed. We deri... This paper mainly addresses maximum likelihood estimation for a response-selective stratified sampling scheme, the basic stratified sampling (BSS), in which the maximum subsample size in each stratum is fixed. We derived the complete-data likelihood for BSS, and extended it as a full-data likelihood by incorporating incomplete data. We also similarly extended the empirical proportion likelihood approach for consistent and efficient estimation. We conducted a simulation study to compare these two new approaches with the existing estimation methods in BSS. Our result indicates that they perform as well as the standard full information likelihood approach. Methods were illustrated using a growth model for fish size at age, including between-individual variability. One of our major conclusions is that the fully observed BSS data, the partially observed data used for stratification, and the sampling strategy are all important in constructing a consistent and efficient estimator. 展开更多
关键词 Length-stratified Age Sampling Response-Selective Sampling Basic stratified Sampling Complete-Data LIKELIHOOD Empirical PROPORTION LIKELIHOOD
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On The Necessity of Stratified English Teaching in Higher Vocational Colleges
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作者 张天华 《海外英语》 2013年第16期53-54,共2页
The practice of stratified English teaching is determined by the features of vocational education. In addition, it is an inexorable trend of current higher education reform, and also a fundamental demand of higher voc... The practice of stratified English teaching is determined by the features of vocational education. In addition, it is an inexorable trend of current higher education reform, and also a fundamental demand of higher vocational education and quality-oriented education. This thesis argues for the need of stratified English teaching in high vocational colleges. 展开更多
关键词 Higher VOCATIONAL COLLEGES stratified English TEAC
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Metallogenetic Mechanism and Timing of Late Superimposing Fluid Mineralization in the Dongguashan Diplogenetic Stratified Copper Deposit,Anhui Province 被引量:21
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作者 XUZhaowen LUXiancai +5 位作者 LINGHongfei LUJianjun JIANGShoyong NIEGuiping HUANGShunsheng HUAMing 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2005年第3期405-413,共9页
An important diplogenetic mineralization event superimposed on pre-existing exhalation sediments in the Tongling area, Anhui province, was triggered by widespread granitic magmatism along the northeastern margin of th... An important diplogenetic mineralization event superimposed on pre-existing exhalation sediments in the Tongling area, Anhui province, was triggered by widespread granitic magmatism along the northeastern margin of the Yangtze Block during 140–135 Ma under extensional tectonic circumstances following the collision between the North China and Yangtze blocks. The main orebodies of the Dongguashan copper deposit, a typical diplogenetic stratified deposit among many polymetallic ore deposits in China, are hosted by strata between Upper Devonian sandstone and Carboniferous limestone, and its mineralization was genetically related to the Qingshanjiao intrusive. The Rb-Sr isotopic isochron of the Qingshanjiao intrusive yields an age of about 136.5±1.4 Ma. The ore-forming fluid reflected by the inclusion fluid in quartz veins is characterized by high temperature and high salinity, and its age was also determined by Rb -Sr isotope dating as 134±11 Ma. Oxygen and hydrogen isotope composition data suggest that the ore-forming fluid was derived mainly from magmatism. By integrating these isotopic dating data, characteristics of fluid inclusions and the geology of the deposit, the mineralization of the Dongguashan copper deposit is divided into two stages. First, a stratiform sedimentary deposit or protore layer formed in the Late Devonian to the Early Carboniferous, while in the second stage the pre-existing protore was superimposed by hydrothermal fluid that was derived from the Yanshanian magmatic activities occurring around 135 Ma ago. This two-stage mineralization formed the Dongguashan statiform copper deposit. Associated “porphyry” mineralization found in the bottom of and in surrounding intrusive rocks of the orebodies might have occurred in the same period as a second-stage mineralization of this deposit. 展开更多
关键词 stratified copper deposit hydrothermal diplogenetic mineralization fluid inclusion metallogenetic epoch
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Mechanical properties and failure modes of stratified backfill under triaxial cyclic loading and unloading 被引量:14
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作者 Wang Jie Song Weidong +1 位作者 Cao Shuai Tan Yuye 《International Journal of Mining Science and Technology》 SCIE EI CSCD 2019年第5期809-814,共6页
Multiple filling of gobs will lead to a layered structure of the backfill.To explore the influence of layering structure on the mechanical properties and failure modes of backfill,different backfill specimens were pre... Multiple filling of gobs will lead to a layered structure of the backfill.To explore the influence of layering structure on the mechanical properties and failure modes of backfill,different backfill specimens were prepared with a cement/sand ratio of 1:4,a slurry concentration of 75%,and backfilling times of 1,2,3 and 4,separately.Triaxial cyclic loading and unloading experiments were carried out.The results show that with an increase in backfilling time,the peak strength of backfill decreases as a polynomial function and the peak strain increases as an exponential function.The cyclic load enhances the linear characteristic of backfill deformation.The loading and unloading deformation moduli have a linear negative correlation with the backfilling time.The unloading deformation modulus is always slightly higher than the loading deformation modulus.The failure modes of stratified backfill are mainly characterized by conjugate shear failure at the upper layer and tensile failure across the layer plane,and there is usually no damage in the lower layer away from the loading area. 展开更多
关键词 stratified BACKFILL TRIAXIAL cyclic loading and UNLOADING Mechanical properties Failure MODES Deformation MODULUS
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Gas-water stratified flow patterns from electromagnetic tomography 被引量:7
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作者 Wang Xiaoxing Wu Xiling 《Petroleum Science》 SCIE CAS CSCD 2009年第3期254-258,共5页
Because of gravitational differentiation of multi-phase fluids, gas-water flow is usually stratified in highly inclined or horizontal gas wells. By using electrode arrays to scan flowing fluids, electromagnetic tomogr... Because of gravitational differentiation of multi-phase fluids, gas-water flow is usually stratified in highly inclined or horizontal gas wells. By using electrode arrays to scan flowing fluids, electromagnetic tomography can identify the flow patterns of mixed fluid from the different electrical properties of gas and water. The responses for different gas-water interface locations were calculated and then physical measurements were undertaken. We compared the results of the numerical simulation with the experimental data, and found that the response characteristics were consistent in the circumstances of uniform physical fields and stratified flows. By analyzing the signal characteristics, it is found that, with the change of the interface location, the response curves showed "steps" whose position and width were decided by the location of fluid interface. The measurement accuracy of this method depended on the vertical distance between adjacent electrodes. The results showed that computer simulation can simulate the measurement of the electromagnetic tomography accurately, so the physical experiment can be replaced. 展开更多
关键词 Electromagnetic tomography stratified flow GAS-WATER numerical simulation physical experiment
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Suppressing by-product via stratified adsorption effect to assist highly reversible zinc anode in aqueous electrolyte 被引量:10
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作者 Miao Zhou Shan Guo +5 位作者 Guozhao Fang Hemeng Sun Xinxin Cao Jiang Zhou Anqiang Pan Shuquan Liang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2021年第4期549-556,共8页
The development of promising zinc anodes mainly suffers from their low plating/stripping coulombic efficiencies when using aqueous electrolyte,which are mainly associated with the interfacial formation of irreversible... The development of promising zinc anodes mainly suffers from their low plating/stripping coulombic efficiencies when using aqueous electrolyte,which are mainly associated with the interfacial formation of irreversible by-products.It is urgent to develop technologies that can solve this issue fundamentally.Herein,we report an artificial Sc_(2)O_(3) protective film to construct a new class of interface for Zn anode.The density functional theory simulation and experimental results have proven that the interfacial side reaction was inhibited via a stratified adsorption effect between this artificial layer and Zn anode.Benefiting from this novel structure,the Sc_(2)O_(3)-coated Zn anode can run for more than 100 cycles without short circuit and exhibit low voltage hysteresis,and the coulombic efficiency increases by 1.2%.Importantly,it shows a good application prospect when matched with two of popular manganese-based and vanadium-based cathodes.The excellent electrochemical performance of the Sc_(2)O_(3)-coated Zn anode highlights the importance of rational design of anode materials and demonstrates a good way for developing high-performance Zn anodes with long lifespan and high efficiency. 展开更多
关键词 Zn anode Artificial protective film stratified adsorption Interfacial reaction Zn4SO4(OH)6·H2O by-products
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Failure mode and strength anisotropic characteristic of stratified rock mass under uniaxial compressive situation 被引量:4
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作者 鲁光银 朱自强 +1 位作者 柳群义 何现启 《Journal of Central South University》 SCIE EI CAS 2009年第4期663-668,共6页
A stratified rock mass model was founded by FLAC^3D. The failure mode and anisotropic characteristic of strength for stratified rock mass were analyzed. The analysis results show that the numerical simulation can visu... A stratified rock mass model was founded by FLAC^3D. The failure mode and anisotropic characteristic of strength for stratified rock mass were analyzed. The analysis results show that the numerical simulation can visually reflect the failure modes of rock samples under different inclination angles β of structural plane. The stiffness of rock sample before peak strength changes in the compressive procedure. With the increase of β, the compressive strength σc of rock sample decreases firstly and then increases; when β is in the range of 20°-30° and 80°-90°, σc has the largest sensitivity to r; while β falls in the range of 30°-70°, σc varies little. When φj〈β〈90° ( φj is friction angle of structure plane), the results obtained from numerical simulation and theoretical analysis are in almost the same values; while β〈 φj or β=90°, they are in great different values. The results obtained from theoretical analysis are obvious larger than those from numerical simulation; and the results from numerical simulation can reflect the difference of compressive strength of rock samples for the two situations of β≥φj and β=90°, which is in more accordance with the real situation. 展开更多
关键词 stratified rock mass failure mode STRENGTH anisotropic characteristic numerical analysis
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A novel method for chemistry tabulation of strained premixed/stratified flames based on principal component analysis 被引量:4
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作者 Peng TANG Hongda ZHANG +2 位作者 Taohong YE Zhou YU Zhaoyang XIA 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2018年第6期855-866,共12页
The principal component analysis (PCA) is used to analyze the high dimen- sional chemistry data of laminar premixed/stratified flames under strain effects. The first few principal components (PCs) with larger cont... The principal component analysis (PCA) is used to analyze the high dimen- sional chemistry data of laminar premixed/stratified flames under strain effects. The first few principal components (PCs) with larger contribution ratios axe chosen as the tabu- lated scalars to build the look-up chemistry table. Prior tests show that strained premixed flame structure can be well reconstructed. To highlight the physical meanings of the tabu- lated scalars in stratified flames, a modified PCA method is developed, where the mixture fraction is used to replace one of the PCs with the highest correlation coefficient. The other two tabulated scalars are then modified with the Schmidt orthogonalization. The modified tabulated scalars not only have clear physical meanings, but also contain passive scalars. The PCA method has good commonality, and can be extended for building the thermo-chemistry table including strain rate effects when different fuels are used. 展开更多
关键词 premixed flame stratified flame strain rate principal component analysis(PCA) chemistry table
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Stability of Stratified Gas-Liquid Flow in Horizontal and Near Horizontal Pipes 被引量:3
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作者 顾汉洋 郭烈锦 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2007年第5期619-625,共7页
A viscous Kelvin-Helmholtz criterion of the interfacial wave instability is proposed in this paper based on the linear stability analysis of a transient one-dimensional two-fluid model. In thismodel, the pressure is e... A viscous Kelvin-Helmholtz criterion of the interfacial wave instability is proposed in this paper based on the linear stability analysis of a transient one-dimensional two-fluid model. In thismodel, the pressure is evaluated using the local momentum balance rather than the hydrostatic approximation. The criterion predicts well the stability limit of stratified flow in horizontal and nearly horizontal pipes. The experimental and theoretical investigation on the effect of pipe inclination on the interfacial instability are carded out. It is found that the critical liquid height at the onset of interfacial wave instability is insensitive to the pipe inclination. However, the pipe inclination significantly affects critical superficial liquid velocity and wave velocity especially lor low gas velocities. 展开更多
关键词 two-fluid model Kelvin-Helmholtz criterion interfacial instability gas-liquid stratified flow
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