期刊文献+
共找到70,250篇文章
< 1 2 250 >
每页显示 20 50 100
Influences of maximum principal stress direction and cross-section shape on tunnel stability 被引量:1
1
作者 Xuefeng Si Zilong Zhang +4 位作者 Xibing Li Guansheng Yi Yong Luo Lihai Tan Kaifeng Han 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第4期2159-2180,共22页
To investigate the effects of the maximum principal stress direction(θ)and cross-section shape on the failure characteristics of sandstone,true-triaxial compression experiments were conducted using cubic samples with... To investigate the effects of the maximum principal stress direction(θ)and cross-section shape on the failure characteristics of sandstone,true-triaxial compression experiments were conducted using cubic samples with rectangular,circular,and D-shaped holes.Asθincreases from 0°to 60°in the rectangular hole,the left failure location shifts from the left corner to the left sidewall,the left corner,and then the floor,while the right failure location shifts from the right corner to the right sidewall,right roof corner,and then the roof.Furthermore,the initial failure vertical stress first decreases and then increases.In comparison,the failure severity in the rectangular hole decreases for variousθvalues as 30°>45°>60°>0°.With increasingθ,the fractal dimension(D)of rock slices first increases and then decreases.For the rectangular and D-shaped holes,whenθ=0°,30°,and 90°,D for the rectangular hole is less than that of the D-shaped hole.Whenθ=45°and 60°,D for the rectangular hole is greater than that of the D-shaped hole.Theoretical analysis indicates that the stress concentration at the rectangular and D-shaped corners is greater than the other areas.The failure location rotates with the rotation ofθ,and the failure occurs on the side with a high concentration of compressive stress,while the side with the tensile and compressive stresses remains relatively stable.Therefore,the fundamental reason for the rotation of failure location is the rotation of stress concentration,and the external influencing factor is the rotation ofθ. 展开更多
关键词 Maximum principal stress direction cross-section shape True-triaxial experiment Failure characteristics Fractal dimension Theoretical analysis
在线阅读 下载PDF
Influences of the Helical Strake Cross-Section Shape on Vortex-Induced Vibrations Suppression for A Long Flexible Cylinder 被引量:11
2
作者 XU Wan-hai LUAN Ying-sen +1 位作者 LIU Li-qin WU Ying-xiang 《China Ocean Engineering》 SCIE EI CSCD 2017年第4期438-446,共9页
An experimental study on a bare flexible cylinder as well as cylinders fitted with two types of cross-sectioned helical strakes was carried out in a towing tank. The main purpose of this paper is to investigate the ef... An experimental study on a bare flexible cylinder as well as cylinders fitted with two types of cross-sectioned helical strakes was carried out in a towing tank. The main purpose of this paper is to investigate the effects of strakes’ cross-section on the vortex-induced vibrations (VIV) suppression of a flexible cylinder. The square-sectioned and round-sectioned helical strakes were selected in the experimental tests. The uniform current was generated by towing the cylinder models along the tank using a towing carriage. The Reynolds number was in the range of 800–16000. The strain responses were measured by the strain gages in cross-flow (CF) and in-line (IL) directions. A modal analysis method was adopted to obtain the displacement responses using the strain signals in different measurement positions. The comparison of the experimental results among the bare cylinder, square-sectioned straked cylinder and round-sectioned straked cylinder was performed. The helical strakes can effectively reduce the strain amplitude, displacement amplitude, response frequencies and dominant modes of a flexible cylinder excited by VIV. And the mean drag coefficients of straked cylinders were approximately consistent with each other. In addition, the square-sectioned and round-sectioned strakes nearly share the similar VIV reduction behaviors. Sometimes, the strakes with round-section represent more excellent effects on the VIV suppression of response frequency than those with square-section. 展开更多
关键词 helical strakes VIV suppression cross-section shape flexible cylinder
在线阅读 下载PDF
Changes in River Cross-section Morphology and Response to Streamflow and Sediment Processes in Middle Reaches of Yellow River,China
3
作者 WEN Yongfu LI Pengfei +4 位作者 LI Mengzhen MA Chaohui GAO Peng MU Xingmin ZHAO Guangju 《Chinese Geographical Science》 2025年第1期161-174,共14页
Changes in river cross-section morphology have decisive influences on the flood discharge and sand transport capacity of rivers;thus,these changes strongly reflect the vitality of a river.In this paper,based on the ri... Changes in river cross-section morphology have decisive influences on the flood discharge and sand transport capacity of rivers;thus,these changes strongly reflect the vitality of a river.In this paper,based on the river cross-section and water and sediment data of two different periods(1974−1987 and 2007−2021),the trend analysis,change-point analysis and sediment rating curve method were used to analyze the change process of river cross-section morphology and its response to streamflow and sediment changes in the main river stream of the Yellow River at the Longmen hydrological station.From 1974 to 1987(except in 1977),the riverbed experi-enced siltation,and the riverbed elevation rose.Conversely,from 2007 to 2021,the riverbed experienced scouring,and the riverbed el-evation gradually decreased.The cross-section shape changed from rectangular to U-shaped(deeper on the right side)at the Longmen cross-section.The changes in streamflow and sediment processes significantly impacted the evolution of river cross-section.Stream-flow(P<0.05),sediment discharge(P<0.01),and the sediment load coefficients(P<0.01)decreased significantly.The relationship between the water depth and sediment load coefficients followed a power function.The decreasing trend in sediment discharge was sig-nificantly stronger than that in streamflow.Suspended sediment particles tended to become finer.The sediment rating curve indicates that the sediment supply from upstream decreased while the erosive power in the river channel increased,leading to a gradual decline in riverbed elevation at the Longmen cross-section from 2007 to 2021.These findings help us better understand the impacts of ecological restoration on changes in river streamflow and sediment during river evolution. 展开更多
关键词 cross-section shape riverbed elevation water depth streamflow sediment discharge eco-restoration Longmen station middle reaches of the Yellow River China
在线阅读 下载PDF
The recirculation flow after different cross-section shaped high-rise buildings with applications to ventilation assessment and drag parameterization
4
作者 Keyi Chen Ziwei Mo Jian Hang 《Building Simulation》 SCIE EI CSCD 2024年第4期509-524,共16页
The building cross-section shape significantly affects the flow characteristics around buildings,especially the recirculation region behind the high-rise building.Eight generic building shapes including square,triangl... The building cross-section shape significantly affects the flow characteristics around buildings,especially the recirculation region behind the high-rise building.Eight generic building shapes including square,triangle,octagon,T-shaped,cross-shaped,#-shaped,H-shaped and L-shaped are examined to elucidate their effects on the flow patterns,recirculation length L and areas A using computational fluid dynamics(CFD)simulations with Reynolds-averaged Navier-Stokes(RANS)approach.The sizes and positions of the vortexes behind the buildings are found to be substantially affected by the building shapes and subsequently changing the recirculation flows.The recirculation length L is in the range of 1.6b-2.6b with an average of 2b.The maximum L is found for L-shaped building(2.6b)while the shortest behind octagon building(1.6b).The vertical recirculation area Av is in the range of 1.5b^(2)-3.2b^(2)and horizontal area Ah in 0.9b^(2)-2.2b^(2).The L,Av and Ah generally increase with increasing approaching frontal area when the wind direction changes but subject to the dent structures of the#-shaped and cross-shaped buildings.The area-averaged wind velocity ratio(AVR),which is proposed to assess the ventilation performance,is in the range of 0.05 and 0.14,which is around a three-fold difference among the different building shapes.The drag coefficient parameterized by Ah varies significantly,suggesting that previous models without accounting for building shape effect could result in large uncertainty in the drag predictions.These findings provide important reference for improving pedestrian wind environment and shed some light on refining the urban canopy parameterization by considering the building shape effect. 展开更多
关键词 recirculation region cross-section shape ventilation assessment drag parameterization computational fluid dynamics
原文传递
Fabrication of High-Density Out-of-Plane Microneedle Arrays with Various Heights and Diverse Cross-Sectional Shapes 被引量:3
5
作者 Hyeonhee Roh Young Jun Yoon +4 位作者 Jin Soo Park Dong-Hyun Kang Seung Min Kwak Byung Chul Lee Maesoon Im 《Nano-Micro Letters》 SCIE EI CAS CSCD 2022年第2期60-78,共19页
Out-of-plane microneedle structures are widely used in various applications such as transcutaneous drug delivery and neural signal recording for brain machine interface.This work presents a novel but simple method to ... Out-of-plane microneedle structures are widely used in various applications such as transcutaneous drug delivery and neural signal recording for brain machine interface.This work presents a novel but simple method to fabricate high-density silicon(Si)microneedle arrays with various heights and diverse cross-sectional shapes depending on photomask pattern designs.The proposed fabrication method is composed of a single photolithography and two subsequent deep reactive ion etching(DRIE)steps.First,a photoresist layer was patterned on a Si substrate to define areas to be etched,which will eventually determine the final location and shape of each individual microneedle.Then,the 1st DRIE step created deep trenches with a highly anisotropic etching of the Si substrate.Subsequently,the photoresist was removed for more isotropic etching;the 2nd DRIE isolated and sharpened microneedles from the predefined trench structures.Depending on diverse photomask designs,the 2nd DRIE formed arrays of microneedles that have various height distributions,as well as diverse cross-sectional shapes across the substrate.With these simple steps,high-aspect ratio microneedles were created in the high density of up to 625 microneedles mm^(-2)on a Si wafer.Insertion tests showed a small force as low as~172μN/microneedle is required for microneedle arrays to penetrate the dura mater of a mouse brain.To demonstrate a feasibility of drug delivery application,we also implemented silk microneedle arrays using molding processes.The fabrication method of the present study is expected to be broadly applicable to create microneedle structures for drug delivery,neuroprosthetic devices,and so on. 展开更多
关键词 MICRONEEDLE Various heights cross-sectional shapes Isotropic etch Deep reactive ion etching
在线阅读 下载PDF
The Optimal Cross-section Design of the “Trapezoid-V” Shaped Drainage Canal of Viscous Debris Flow 被引量:9
6
作者 YOU Yong PAN Huali +1 位作者 LIU Jinfeng OU Guoqiang 《Journal of Mountain Science》 SCIE CSCD 2011年第1期103-107,共5页
Debris flow drainage canal is one of the most widely used engineering measures to prevent and manage debris flow hazards.The shape and the sizes of the cross-section are important parameters when design debris flow dr... Debris flow drainage canal is one of the most widely used engineering measures to prevent and manage debris flow hazards.The shape and the sizes of the cross-section are important parameters when design debris flow drainage canal.Therefore,how to design the appropriate shape and sizes of the cross-section so that the drainage canal can have the optimal drainage capacity is very important and few researched at home and abroad.This study was conducted to analyze the hydraulic condition of a Trapezoid-V shaped drainage canal and optimize its cross-section.By assuming characteristic sizes of the cross-section,the paper deduced the configuration parameter of the cross-section of a Trapezoid-V shaped debris flow drainage canal.By theory analysis,it indicates that the optimal configuration parameter is only related to the side slope coefficient and the bottom transverse slope coefficient.For this study,the Heishui Gully,a first-order tributary of the lower Jinsha River,was used as an example to design the optimal cross-section of the drainage canal of debris flow. 展开更多
关键词 Optimal cross-section design Trapezoid-V shaped Drainage canal Viscous debris flow
原文传递
Association between Non-high-density Lipoprotein Cholesterol to High-density Lipoprotein Cholesterol Ratio(NHHR)and Stroke among Adults in the USA:A Cross-Sectional NHANES Study 被引量:2
7
作者 Haixia Ma Huaqiu Chen Peichang Wang 《Biomedical and Environmental Sciences》 2025年第1期37-46,共10页
Objective The relationship between non-high-density lipoprotein(NHDL)cholesterol to high-density lipoprotein cholesterol(HDL-C)ratio(NHHR)and stoke remains unknown.This study aimed to evaluate the association between ... Objective The relationship between non-high-density lipoprotein(NHDL)cholesterol to high-density lipoprotein cholesterol(HDL-C)ratio(NHHR)and stoke remains unknown.This study aimed to evaluate the association between the adult NHHR and stroke occurrence in the United States of America(USA).Methods To clarify the relationship between the NHHR and stroke risk,this study used a multivariable logistic regression model and a restricted cubic spline(RCS)model to investigate the association between the NHHR and stroke,and data from the National Health and Nutrition Examination Survey(NHANES)from 2005 to 2018.Subgroup and sensitivity analyses were conducted to test the robustness of the results.Results This study included 29,928 adult participants,of which 1,165 participants had a history of stroke.Logistic regression analysis of variables demonstrated a positive association between NHHR and stroke(OR 1.24,95%CI:1.03-1.50,P=0.026).Compared with the lowest reference group of NHHR,participants in the second,third,and fourth quartile had a significantly increased risk of stroke after full adjustments(OR:1.35,95%CI:1.08-1.69)(OR:1.83,95%CI:1.42-2.36)(OR:2.04,95%CI:1.50-2.79).In the total population,a nonlinear dose-response relationship was observed between the NHHR and stroke risk(P non-linearity=0.002).This association remained significant in several subgroup analyses.Further investigation of the NHHR may enhance our understanding of stroke prevention and treatment.Conclusion Our findings suggest a positive correlation between the NHHR and an increased prevalence of stroke,potentially serving as a novel predictive factor for stroke.Timely intervention and management of the NHHR may effectively mitigate stroke occurrence.Prospective studies are required to validate this association and further explore the underlying biological mechanisms. 展开更多
关键词 NHHR STROKE NHANES cross-sectional study
暂未订购
Research on Multi-Level Automatic Filling Optimization Design Method for Layered Cross-Sectional Layout of Umbilical 被引量:1
8
作者 YIN Xu FAN Zhi-rui +4 位作者 CAO Dong-hui LIU Yu-jie LI Meng-shu YAN Jun YANG Zhi-xun 《China Ocean Engineering》 2025年第5期891-903,共13页
The umbilical,a key component in offshore energy extraction,plays a vital role in ensuring the stable operation of the entire production system.The extensive variety of cross-sectional components creates highly comple... The umbilical,a key component in offshore energy extraction,plays a vital role in ensuring the stable operation of the entire production system.The extensive variety of cross-sectional components creates highly complex layout combinations.Furthermore,due to constraints in component quantity and geometry within the cross-sectional layout,filler bodies must be incorporated to maintain cross-section performance.Conventional design approaches based on manual experience suffer from inefficiency,high variability,and difficulties in quantification.This paper presents a multi-level automatic filling optimization design method for umbilical cross-sectional layouts to address these limitations.Initially,the research establishes a multi-objective optimization model that considers compactness,balance,and wear resistance of the cross-section,employing an enhanced genetic algorithm to achieve a near-optimal layout.Subsequently,the study implements an image processing-based vacancy detection technique to accurately identify cross-sectional gaps.To manage the variability and diversity of these vacant regions,the research introduces a multi-level filling method that strategically selects and places filler bodies of varying dimensions,overcoming the constraints of uniform-size fillers.Additionally,the method incorporates a hierarchical strategy that subdivides the complex cross-section into multiple layers,enabling layer-by-layer optimization and filling.This approach reduces manufac-turing equipment requirements while ensuring practical production process feasibility.The methodology is validated through a specific umbilical case study.The results demonstrate improvements in compactness,balance,and wear resistance compared with the initial cross-section,offering novel insights and valuable references for filler design in umbilical cross-sections. 展开更多
关键词 UMBILICAL cross-sectional layout multi-level filling layered layout optimization design
在线阅读 下载PDF
Occupational influences on dietary quality among postpartum women:a cross-sectional study in Beijing,China 被引量:1
9
作者 Jian Zhao Min Zhang 《Global Health Journal》 2025年第2期94-103,共10页
Objective:Postpartum nutrition plays a critical role in maternal recovery and long-term health.However,the nutritional status of working mothers in the postpartum period remains understudied.This study aimed to assess... Objective:Postpartum nutrition plays a critical role in maternal recovery and long-term health.However,the nutritional status of working mothers in the postpartum period remains understudied.This study aimed to assess the dietary quality of postpartum women in urban Beijing,identify occupational-related factors influencing their diet,and explore potential interventions to improve maternal nutrition during the postpartum period.Methods:In this cross-sectional analysis,554 women one year after delivery were recruited from ten community health centers.Sociodemographic,occupational and postpartum care variables were collected via questionnaire.Dietary intake over the preceding year was assessed using a food frequency questionnaire.The modified dietary balance index for postpartum women were used for dietary quality assessment.Results:The study revealed severe dietary imbalances among postpartum women,characterized by excessive consumption of cereals,eggs,and meats,while their intake of vegetables,fruits,and dairy products was inadequate.According to dietary balance index for postpartum women,66.25%of mothers showed varying degrees of excessive intake.45.31%of mothers experienced varying levels of insufficient intake,with only 19.86%of participants having a relatively balanced diet.Occupational differences were observed,with women in the commercial employment group showing higher levels of excessive food intake.The analysis of influencing factors showed that family monthly income,maternity leave,and postpartum care significantly affected the dietary quality.Conclusions:Postpartum women in Beijing experience widespread dietary imbalances,with both excesses and deficiencies.Occupational context and related factors significantly shape diet quality.These findings highlight the need for targeted nutritional interventions tailored to the specific challenges of different occupational groups. 展开更多
关键词 Postpartum dietary quality Dietarybalance index Occupational factors Maternal health cross-sectional study
暂未订购
Effect of cross-section shape of rotating chute on particle movement and distribution at the throat of a bell-less top blast furnace 被引量:4
10
作者 Mingyin Kou Jian Xu +4 位作者 Shengli Wu Heng Zhou Kai Gu Shun Yao Bingjie Wen 《Particuology》 SCIE EI CAS CSCD 2019年第3期194-206,共13页
Rotating chutes are widely used to control the burden distribution and enhance the gas distribution in a blast furnace.The chute cross-section shape has a significant effect on the particle movement and distribution.T... Rotating chutes are widely used to control the burden distribution and enhance the gas distribution in a blast furnace.The chute cross-section shape has a significant effect on the particle movement and distribution.Therefore,this study developed a three-dimensional model of a blast furnace top with rotating chute using the discrete element method.The effect of different chute shapes on the particle movement and radial burden distribution was then investigated.The results showed that the burden stream height at the chute discharge agrees well with the burden stream thickness at the burden surface.A semicircular chute had the largest main striking point,where the chute discharge joins the burden surface,and trapezoidal and rectangular chutes had successively smaller MSPs.The semicircular chute helped to obtain a uniform radial size distribution.The trapezoidal chute helped form an aggregated burden stream at low rotating speeds,while the rectangular shape chute achieved this at higher rotating speeds and different chute angles. 展开更多
关键词 Blast FURNACE CHUTE shape BURDEN size SEGREGATION Discrete element method
原文传递
Gut microbial characteristics of the damp-heat constitution:a population-based multicenter cross-sectional study 被引量:1
11
作者 LI Tianxing ZHU Linghui +9 位作者 WANG Xueke TANG Jun YANG Lingling PANG Guoming LI Huang WANG Liying DONG Yang ZHAO Shipeng LI Yingshuai LI Lingru 《Journal of Traditional Chinese Medicine》 2025年第1期140-151,共12页
OBJECTIVE:To investigate the difference in gut microbiota between population with damp-heat constitution(DHC)and balanced constitution(BC).METHODS:A multi-centered cross-sectional casecontrol study was conducted,which... OBJECTIVE:To investigate the difference in gut microbiota between population with damp-heat constitution(DHC)and balanced constitution(BC).METHODS:A multi-centered cross-sectional casecontrol study was conducted,which included 249 participants with damp-heat constitution or balanced constitution.Baseline information of participants was collected,and stool samples were collected for gut microbiota analysis.Principal coordinate analysis,linear discriminant analysis effect size analysis,receiver operating characteristic,random forest model,and phylogenetic investigation of communities by reconstruction of unobserved states methods were used to reveal the relationship between gut microbiota and the damp-heat constitution.RESULTS:Compared to those in the BC group,the richness and diversity of the microbiota,specifically those of several short-chain fatty acid producing genera such as Barnesiella,Coprobacter,and Butyricimonas,were significantly decreased in the DHC group.Regarding biological functions,flavonoid biosynthesis,propanoate metabolism,and nucleotide sugar metabolism were suppressed,while arachidonic acid metabolism and glutathione metabolism were enriched in the DHC group.Finally,a classifier based on the microbiota was constructed to discriminate between the DHC and BC populations.CONCLUSION:The gut microbiota of the DHC population exhibits significantly reduced diversity and is closely related to inflammation,metabolic disorders,and liver steatosis,which is consistent with clinical observations,thus serving as a potential diagnostic tool for traditional Chinese medicine constitution discrimination. 展开更多
关键词 damp-heat constitution balanced constitution Traditional Chinese medicine constitution MICROBIOTA inflammatory PICRUSt multicenter study cross-sectional studies
原文传递
Optimization of Cross-sectional Shapes of the Bi-2223/Ag Wires before Flat Rolling
12
作者 LU Yongjin ZENG Pan +1 位作者 LEI Liping SUN Jianfeng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2009年第6期890-895,共6页
Rolling process plays an important role in the manufacture of Bi-based high temperature superconductor tapes, and the plastic flow regularities of the superconducting wires during deformation will directly affect the ... Rolling process plays an important role in the manufacture of Bi-based high temperature superconductor tapes, and the plastic flow regularities of the superconducting wires during deformation will directly affect the ultimate quality of the tapes. In order to investigate the effect of cross-sectional shapes before fiat rolling on the performance and homogeneity of the tapes, some numerical models of Bi-2223/Ag wires with different cross-sectional shapes including circular, square, elliptical and racetrack cross-sections are constructed during the rolling process. By comparing the relative density, logarithmic strain ratio and length-width ratio on the filaments, it is revealed that Bi-2223/Ag wire with special-shaped cross-section can achieve better conductivity than the round wire, in particular, the racetrack cross-sectional wire has the second best performance among four wires. Based on material processability and experimental condition, tri-pass racetrack drawing technique is employed to optimize the process and obtain racetrack cross-sectional wire. The rolling process of Bi-2223/Ag wire with racetrack cross-section causes more intensive deformation of filaments in the center of the tape and achieves the filaments with larger length-width ratio. Also, the deformation distribution of filaments verifies the numerical results. Consequently, the racetrack drawing technique can be utilized for a reference during the mechanical processing and to increase the current transmission capacities of Bi-2223/Ag tapes. 展开更多
关键词 ROLLING cross-sectional shape FILAMENT modelling
在线阅读 下载PDF
Hyperstatic reaction method for calculations of tunnels with horseshoe-shaped cross-section under the impact of earthquakes 被引量:1
13
作者 Thanh Nguyen Chi Gospodarikov Alexandr 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2020年第1期179-188,共10页
Tunnels are now an integral part of the infrastructure in major cities around the world. For many reasons, these tunnels have horseshoe-shaped cross-sections with round top and flat bottom. This paper presents some im... Tunnels are now an integral part of the infrastructure in major cities around the world. For many reasons, these tunnels have horseshoe-shaped cross-sections with round top and flat bottom. This paper presents some improvements to the use of the Hyperstatic Reaction Method-HRM for analysing tunnels with horseshoe-shaped cross-sections when these tunnels operate under the influence of earthquakes, particularly in cases when the tunnel lining is a continuous lining. The analysis used parameters of a tunnel from the Hanoi metro system, as well as parameters of the strongest earthquake that may occur in the central Hanoi area in the improved HRM and 2 D numerical methods using the ABAQUS software. On the basis of the results obtained, the paper gives conclusions about the HRM methodology when it is used to calculate tunnels that have horseshoe cross-sections operating under the influence of earthquakes. 展开更多
关键词 hyperstatic reaction method earthquake horseshoe cross-section impact tunnel
在线阅读 下载PDF
The L-shaped association between superoxide dismutase levels and blood pressure in older Chinese adults:community-based,cross-sectional study 被引量:1
14
作者 Ying HUANG Wei LAI +3 位作者 Hong CHEN Qi-Fan LIU Ju-Xiang LI Jin-Zhu HU 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2022年第1期71-82,共12页
BACKGROUND As an antioxidant,serum superoxide dismutase(SOD)have been found to be associated with hypertension.METHODS The data were derived from the Chinese Longitudinal Healthy Longevity Survey(CLHLS),a prospective ... BACKGROUND As an antioxidant,serum superoxide dismutase(SOD)have been found to be associated with hypertension.METHODS The data were derived from the Chinese Longitudinal Healthy Longevity Survey(CLHLS),a prospective cohort study in China.We explored the association between serum SOD and blood pressure(BP)using multivariable correction analysis in an older Chinese population.RESULTS We observed a significantly gradual downward trend in the association between serum SOD levels and diastolic BP(DBP)in participants with lower serum SOD levels(<58 IU/mL),while no associations were observed between serum SOD levels and DBP in participants with higher serum SOD levels(>58 IU/mL).Similar results showed a significant gradual downward trend in associations between serum SOD levels and the risk of diastolic hypertension only at SOD<58 IU/mL.Multiple linear regression analysis suggested that serum SOD was negatively correlated with DBP(Sβ=-0.088,P<0.001)but not with SBP(Sβ=0.013,P=0.607).Multiple logistic regression analysis suggested that serum SOD was independently associated with the risk of diastolic hypertension(OR=0.984,95%CI:0.973−0.996,P=0.010)but not with the risk of systolic hypertension(OR=1.001,95%CI:0.990−1.012,P=0.836))after adjusting for relevant confounding factors.Serum SOD levels(<58 IU/mL,>58 IU/mL)were an effect modifier of the association between serum SOD and DBP(interaction P=0.0038)or the risk of diastolic hypertension(interaction P=0.0050).CONCLUSIONS Our study indicated for the first time that there was an L-shaped association between serum SOD levels and the risk of diastolic hypertension in the older Chinese population. 展开更多
关键词 HYPERTENSION shaped Serum
暂未订购
Effects of tube cross-sectional shapes on flow pattern, liquid film and heat transfer of n-pentane across tube bundles 被引量:1
15
作者 Xuejing He Zhenlin Li +1 位作者 Ji Wang Hai Yu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第8期16-25,共10页
The heat transfer of hydrocarbon refrigerant across tube bundles have been widely used in refrigeration.Three-dimensional simulation model using volume of fluid(VOF) was presented to study the effects of tube shapes o... The heat transfer of hydrocarbon refrigerant across tube bundles have been widely used in refrigeration.Three-dimensional simulation model using volume of fluid(VOF) was presented to study the effects of tube shapes on flow pattern, film thickness and heat transfer of n-pentane across tube bundles, including circle, ellipse-shaped, egg-shaped and cam-shaped tube bundles. Simulation results agree well with experimental data in the literature. The liquid film thickness of sheet flow and heat transfer for different tube shapes were obtained numerically. The flow pattern transition occurs lower vapor quality for ellipse-shaped tube than other tube shapes. For sheet flow, the liquid film on circle tube and ellipseshaped tube is symmetrically distributed along the circumferential direction. However, the liquid film on egg-shaped tube at circumferential angles(θ) = 15°–60° is thicker than θ = 135°–165°. The liquid film on cam tube at θ = 15°–60° is slightly thinner than θ = 135°–165°. The liquid film thickness varies from thinner to thicker for ellipse-shaped, cam-shaped, egg-shape and circle within θ = 15°–60°. The effect of tube shape is insignificant on thin liquid film thickness. Ellipse-shaped tube has largest heat transfer coefficient for sheet flow. In practical engineering, the tube shape could be designed as ellipse to promote heat transfer. 展开更多
关键词 Tube shapes Flow pattern Liquid film thickness Heat transfer Two-phase flow
在线阅读 下载PDF
Optimal Cross-Sectional Shape of Gas/Air Ducts
16
作者 Yongjian Gu 《World Journal of Engineering and Technology》 2016年第3期250-255,共6页
In industrial plants, ships, and buildings, a large amount of gas and air ducts are applied for equipment connection, HVAC, medium transport, and exhaust, etc. These ducts can be designed in varied cross-sectional sha... In industrial plants, ships, and buildings, a large amount of gas and air ducts are applied for equipment connection, HVAC, medium transport, and exhaust, etc. These ducts can be designed in varied cross-sectional shapes, such as round or rectangle. The author reveals through geometric calculation of the duct cross-sectional shapes and engineering experiences that the round cross-section is an optimal shape in the duct system. The round duct has the shorter perimeter than the other cross-sectional shape ducts and the stronger structure in the same working condition. The material saving of the round duct due to the shorter perimeter is quantitatively determined. In the pater, it is shown that the round duct is economically attractive. The economic analysis for the material cost saving is illustrated by an example. For a long duct system, the material and material cost savings are significant. It is suggested that the round duct in the gas and air duct system should have priority as long as the field conditions are allowed. In the paper, the material cost saving is also converted to PW, AW, and FW used for LCC economic analysis. 展开更多
关键词 OPTIMAL Ducts cross-sectional shape Economic and Cost Analysis
在线阅读 下载PDF
Characteristics and trends of bibliometric analysis on acupuncture:A cross-sectional study
17
作者 Zhi-Qiang Li Hui-Juan Cao +9 位作者 Heng Yin Yue Jiang Xue-Feng Wang Chen Shen Kun Wu Zi-Yi Qi Mei-Ling Wang You-Zhu Su Ling-Yao Kong Jian-Ping Liu 《Integrative Medicine Discovery》 2025年第3期1-11,共11页
Background:The bibliometrics of acupuncture are growing rapidly.However,the absence of reporting guidelines may lead to significant duplication and waste,thereby undermining the research’s value.To address this,a kno... Background:The bibliometrics of acupuncture are growing rapidly.However,the absence of reporting guidelines may lead to significant duplication and waste,thereby undermining the research’s value.To address this,a knowledge mapping was generated based on published studies to investigate the characteristics of bibliometric studies on acupuncture and the extent of duplicate publications,with the overarching goal of providing a comprehensive overview of the knowledge structure in this field.Methods:This cross-sectional study used three databases(PubMed,Web of Science,and Scopus)to identify relevant studies up to May 1,2024.In addition,the reference lists were retrieved as a supplement.To track research trends,we employed Microsoft Excel and R software to extract,code,and analyze information.Study selection,data extraction,and validation were performed independently by at least two reviewers.The reporting quality of included studies was assessed using the Preliminary guideline for reporting bibliometric reviews of the biomedical literature(BIBLIO).Results:Among the 6,221 bibliometric reviews examined,113 relevant publications were identified,80 focusing on various diseases/conditions.The annual number of publications has gradually increased,with the output in the past four years being 3.52 times higher than that before 2020.China(106)and Chengdu University of Traditional Chinese Medicine(16)have the highest number of publications.The most prolific author is Fan-Rong Liang,with six articles.The first bibliometric study,by Hai-Yan Li,was published in 2010.Journal of Pain Research,with 36 articles,holds the most publications.The top three diseases:diseases of the nervous system;symptoms,signs,or clinical findings not elsewhere classified;and mental,behavioral,or neurodevelopmental disorders.There may be potential duplication in research on 13 diseases/conditions,notably stroke,migraine,pain/analgesia,cancer pain,shoulder pain,facial paralysis/bell’s palsy,chronic pain,and cognitive impairment.In BIBLIO,the most frequently missing items are issues/topics(item 2),quality assessment(item 11),and descriptive findings(item 13).Conclusion:This study demonstrates that acupuncture bibliometrics is actively utilized to identify dominant diseases/conditions,aiding scholars in understand the knowledge structure and main topics.Although the number of related studies is increasing,with an average of 25 studies annually,overlap in some areas highlights the need for adherence to reporting guidelines and careful topic selection to ensure truly valuable insights and knowledge contributions.The adherence to BIBLIO’s 20 proposed items across analyzed articles,highlighting important in reporting practices. 展开更多
关键词 cross-sectional study ACUPUNCTURE BIBLIOMETRICS evidence mapping
暂未订购
Latent profilesof ambivalence over emotional expression in young breast cancer patients:A cross-sectional study
18
作者 Xiaocen Chen Zhao Wang +3 位作者 Sibo Wang Fang Zhang Xueyu Li Jing Zhao 《International Journal of Nursing Sciences》 2025年第4期379-385,I0004,I0005,共9页
Objectives:This study aimed to classify young breast cancer patients into distinct ambivalence over emotional expression and to explore the factors influencingthe level of ambivalence over emotional expression.Methods... Objectives:This study aimed to classify young breast cancer patients into distinct ambivalence over emotional expression and to explore the factors influencingthe level of ambivalence over emotional expression.Methods:A total of 217 young breast cancer patients were enrolled from a tertiary Grade A oncology hospital in Tianjin,China,using the convenience sampling method.All participants completed the general questionnaire,Ambivalence over Emotion Expression Questionnaire(AEQ),and Family Adapt-Ability and Cohesion Evaluation Scales-Chinese Version(FACES-CV).We employed exploratory latent profileanalysis for ambivalence over emotional expression profilingand logistic regression analysis to identify the influentialfactors Results:The results of the latent profileanalysis supported the models of four latent profiles,which were definedas“low conflict-lowexpression reflection”(19.2%),“high conflict-high inhibition expression”(43.9%),“moderate conflict-highregret expression”(18.1%),and“moderate conflict-desire understand”(18.8%).Logistic regression revealed that family cohesion,marital status,residence,per capita monthly income,and cancer stage were the influencingfactors of ambivalence over emotional expression in young breast cancer patients(P<0.05)Conclusions:Levels of ambivalence over emotional expression ameast cancer patients with breast cancer were highly heterogeneous.Medical staff should provide psychological counseling and health education tailored to the unique characteristics of emotional expression ambivalence in different patient groups to promote healthy emotional expression among patients. 展开更多
关键词 AMBIVALENCE Breast neoplasms cross-sectional studies Emotions NURSING Young adult
暂未订购
Examining emotional intelligence of hospital-based nursing students with comparison between full-time and part-time study modes:A cross-sectional study
19
作者 Joanna Hiu Ki Ko Daniel Yee Tak Fong 《Nursing Communications》 2025年第17期1-6,共6页
association with academic and clinical performance.This study aimed to determine the EI level of hospital-based nursing students and examine differences between full-time and part-time students.Methods:We conducted a ... association with academic and clinical performance.This study aimed to determine the EI level of hospital-based nursing students and examine differences between full-time and part-time students.Methods:We conducted a cross-sectional study in a hospital-based nursing school.EI level was measured using the Schutte Self-report Emotional Intelligence Scale(SSEIS).Results:We recruited 287 participants(mean age:21.9 years).Their mean SSEIS score was 119.6(95%CI=118.57-120.65).The mean SSEIS scores of 172 full-time and 115 part-time nurses were 120.7(95%CI=119.3-122.0)and 118.1(95%CI=116.5-119.6),respectively.There was no significant difference between the groups.Conclusion:The EI difference between full-time and part-time nursing students was statistically insignificant.The need for further EI development among both full-time and part-time students must be addressed. 展开更多
关键词 emotional intelligence nursing education nursing students HOSPITAL-BASED FULL-TIME PART-TIME cross-sectional study
在线阅读 下载PDF
Parent interactions and physical aggression among Indonesian adolescents:a cross-sectional study
20
作者 Yoyok Bekti Pasetyo Alifya Az Zahra +5 位作者 Sri Sunaringsih Ika Wardojo Nur Melizza Anggraini Dwi Kurnia Nur Lailatul Masruroh Titih Huriah Rusnani Ab Latif 《Frontiers of Nursing》 2025年第3期345-354,共10页
Objective:This study aimed to examine the association between parent-child relationships and physically aggressive behavior among adolescents.Methods:This is a cross-sectional study that uses secondary data from the 2... Objective:This study aimed to examine the association between parent-child relationships and physically aggressive behavior among adolescents.Methods:This is a cross-sectional study that uses secondary data from the 2015 Indonesia Global School-Based Health Survey(IGSHS).Health surveys were conducted in 75 schools representing three regions(Sumatra,Java-Bali;Outer Sumatra;and Java-Bali)in 26 provinces and 68 districts/cities in Indonesia(N=10,139 students).Students who participated were aged 12-19 years,were enrolled in public schools in the junior and high school levels.Results:It has been seen that for most middle-aged adolescents(58.7%),their parents(25%-29%)pay less attention to academic assignments(homework),problems,and use of free time.The most significant factors that influence adolescents to commit violence are smoking and consuming alcohol.Adolescents who smoke are twice as likely to commit physical violence compared with adolescents who do not smoke(OR=2.005;95%CI=1.7062-2.396).Meanwhile,adolescents who consume alcohol are 1.8 times more likely to commit physical violence compared with adolescents who do not consume alcohol(OR=1.807;95%CI=1.421-2.298).Conclusions:Through educational activities and consultations,this study’s findings are valuable for establishing parenting programs among those concerned about their children’s aggressive behavior.Meanwhile,counseling programs can be started in schools by conducting self-detection of negative adolescent behavior,such as screening for smoking,alcohol consumption,sleep issues,and attempted suicide. 展开更多
关键词 parent-child relations adolescent behavior SMOKING alcohol drinking VIOLENCE cross-sectional studies Indonesia
暂未订购
上一页 1 2 250 下一页 到第
使用帮助 返回顶部