期刊文献+
共找到382篇文章
< 1 2 20 >
每页显示 20 50 100
Impacts of the unsaturation degree of long-chain fatty acids on the volatile fatty acid profiles of rumen microbial fermentation in goats in vitro 被引量:3
1
作者 GAO Jian WANG Meng-zhi +3 位作者 JING Yu-jia SUN Xue-zhao WU Tian-yi SHI Liang-feng 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2016年第12期2827-2833,共7页
This study investigated the impacts of the degree of unsaturation (unsaturity) of long-chain fatty acids on volatile fatty acid (VFA) profiles of rumen fermentation in vitro. Six types of long-chain fatty acids, i... This study investigated the impacts of the degree of unsaturation (unsaturity) of long-chain fatty acids on volatile fatty acid (VFA) profiles of rumen fermentation in vitro. Six types of long-chain fatty acids, including stearic acid (C18:0, control group), oleic acid (C18:1, n-9), linoleic acid (C18:2, n-6), a-linolenic acid (C18:3, n-3), arachidonic acid (C20:4, n-6) and eicosapentaenoic acid (C20:5, n-3), were tested. Rumen fluid from three goats fitted with ruminal fistulae was used as inoculum and the inclusion rate of long-chain fatty acid was at 3% (w/w) of substrate. Samples were taken for VFA analysis at 0, 3, 6, 9, 12, 18 and 24 h of incubation, respectively. The analysis showed that there were significant differences in the total VFA among treatments, sampling time points, and treatment×time point interactions (P〈0.01). a-Linolenic acid had the highest total VFA (P〈0.01) among different long-chain fatty acids tested. The molar proportion of acetate in total VFA significantly differed among treatments (P〈0.01) and sampling time points (P〈0.01), but not treatment×time point interactions (P〉0.05). In contrast, the molar proportion of propionate did not differ among treatments during the whole incubation (P〉0.05). However, for butyrate molar proportions, significant differences were found not only among sampling time points but also among treatments and treatment×time point interactions (P〈0.01), with eicosapentaenoic acid having the highest value (P〈0.01). Additionally, no statistically significant differences were found in the acetate to propionate ratios among treatments groups (P〉0.05), even the treatments stearic acid and a-linolenic acid were numerically higher than the others. The inclusion of 3% long-chain unsaturated fatty acids differing in the degree of unsaturation brought out a significant quadratic regression relation between the total VFA concentration and the double bond number of fatty acid. In conclusion, the a-linolenic acid with 3 double bonds appeared better for improving rumen microbial fermentation and the total VFA concentration. 展开更多
关键词 volatile fatty acid unsaturation degree long-chain fatty acid in vitro fermentation
下载PDF
Unsaturation index and type 2 diabetes:Unknown,unloved 被引量:1
2
作者 Rob NM Weijers 《World Journal of Meta-Analysis》 2015年第2期89-92,共4页
A useful parameter for interpreting analyses of membrane fatty-acid composition is the unsaturation index(UI),a measure of unsaturation that is calculated as the mean number of cis double bonds per fatty-acid residue ... A useful parameter for interpreting analyses of membrane fatty-acid composition is the unsaturation index(UI),a measure of unsaturation that is calculated as the mean number of cis double bonds per fatty-acid residue multiplied by 100.The UI is a fundamental parameter that contains information about many membrane biophysical properties and behavior.UI is a crucial index for type 2 diabetes(T2D) and other disorders,yet it is not properly considered in the scientific community.The goal of the present editorial is to familiarize the scientific T2 D community with the UI.The idea of early systemic cell-membrane disease necessitates new thinking andsuggests that UI should feature prominently on the research agenda. 展开更多
关键词 Type 2 diabetes unsaturation index PHOSPHOLIPID Cell membrane Fatty acid
下载PDF
Plasma induced grain boundaries to boost electrochemical reduction of CO_(2)to formate
3
作者 Guan Wang Shengtao Zhong +9 位作者 Xiaoqian Xiong Jing Li Fangyuan Wang Li Huo Daoxiong Wu Xingqi Han Zhitong Wang Qi Chen Xinlong Tian Peilin Deng 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第8期636-643,I0014,共9页
Bismuth-based catalysts are highly promising for the electrochemical carbon dioxide reduction reaction(eCO_(2)RR)to formate product.However,achieving high activity and selectivity towards formate and ensuring long-ter... Bismuth-based catalysts are highly promising for the electrochemical carbon dioxide reduction reaction(eCO_(2)RR)to formate product.However,achieving high activity and selectivity towards formate and ensuring long-term stability remains challenging.This work reports the oxygen plasma inducing strategy to construct the abundant grain boundaries of Bi/BiO_x on ultrathin two-dimensional Bi nanosheets.The oxygen plasma-treated Bi nanosheet(OP-Bi)exhibits over 90%Faradaic efficiency(FE)for formate at a wide potential range from-0.5 to-1.1 V,and maintains a great stability catalytic performance without significant decay over 30 h in flow cell.Moreover,membrane electrode assembly(MEA)device with OPBi as catalyst sustains the robust current density of 100 mA cm^(-2)over 50 h,maintaining a formate FE above 90%.In addition,rechargeable Zn-CO_(2)battery presents the peak power density of1.22 mW cm^(-2)with OP-Bi as bifunctional catalyst.The mechanism experiments demonstrate that the high-density grain boundaries of OP-Bi provide more exposed active sites,faster electron transfer capacity,and the stronger intrinsic activity of Bi atoms.In situ spectroscopy and theo retical calculations further elucidate that the unsaturated Bi coordination atoms between the grain boundaries can effectively activate CO_(2)molecules through elongating the C-O bond,and reducing the formation energy barrier of the key intermediate(^(*)OCOH),thereby enhancing the catalytic performance of eCO_(2)RR to formate product. 展开更多
关键词 CO_(2)electroreduction Bi nanosheet Grain boundary unsaturation Bi atoms MEA device
下载PDF
Unsaturated bi-heterometal clusters in metal-vacancy sites of 2D MoS2 for efficient hydrogen evolution 被引量:1
4
作者 Gonglei Shao Jie Xu +4 位作者 Shasha Gao Zhang Zhang Song Liu Xu Zhang Zhen Zhou 《Carbon Energy》 SCIE EI CAS CSCD 2024年第3期264-275,共12页
The valence states and coordination structures of doped heterometal atoms in two-dimensional(2D)nanomaterials lack predictable regulation strategies.Hence,a robust method is proposed to form unsaturated heteroatom clu... The valence states and coordination structures of doped heterometal atoms in two-dimensional(2D)nanomaterials lack predictable regulation strategies.Hence,a robust method is proposed to form unsaturated heteroatom clusters via the metal-vacancy restraint mechanism,which can precisely regulate the bonding and valence state of heterometal atoms doped in 2D molybdenum disulfide.The unsaturated valence state of heterometal Pt and Ru cluster atoms form a spatial coordination structure with Pt–S and Ru–O–S as catalytically active sites.Among them,the strong binding energy of negatively charged suspended S and O sites for H+,as well as the weak adsorption of positively charged unsaturated heterometal atoms for H*,reduces the energy barrier of the hydrogen evolution reaction proved by theoretical calculation.Whereupon,the electrocatalytic hydrogen evolution performance is markedly improved by the ensemble effect of unsaturated heterometal atoms and highlighted with an overpotential of 84 mV and Tafel slope of 68.5 mV dec^(−1).In brief,this metal vacancy-induced valence state regulation of heterometal can manipulate the coordination structure and catalytic activity of heterometal atoms doped in the 2D atomic lattice but not limited to 2D nanomaterials. 展开更多
关键词 CLUSTERS hydrogen evolution reaction metal vacancy MOS2 unsaturated heterometal
下载PDF
Surrogate modeling for unsaturated infiltration via the physics and equality-constrained artificial neural networks 被引量:1
5
作者 Peng Lan Jingjing Su Sheng Zhang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第6期2282-2295,共14页
Machine learning(ML)provides a new surrogate method for investigating groundwater flow dynamics in unsaturated soils.Traditional pure data-driven methods(e.g.deep neural network,DNN)can provide rapid predictions,but t... Machine learning(ML)provides a new surrogate method for investigating groundwater flow dynamics in unsaturated soils.Traditional pure data-driven methods(e.g.deep neural network,DNN)can provide rapid predictions,but they do require sufficient on-site data for accurate training,and lack interpretability to the physical processes within the data.In this paper,we provide a physics and equalityconstrained artificial neural network(PECANN),to derive unsaturated infiltration solutions with a small amount of initial and boundary data.PECANN takes the physics-informed neural network(PINN)as a foundation,encodes the unsaturated infiltration physical laws(i.e.Richards equation,RE)into the loss function,and uses the augmented Lagrangian method to constrain the learning process of the solutions of RE by adding stronger penalty for the initial and boundary conditions.Four unsaturated infiltration cases are designed to test the training performance of PECANN,i.e.one-dimensional(1D)steady-state unsaturated infiltration,1D transient-state infiltration,two-dimensional(2D)transient-state infiltration,and 1D coupled unsaturated infiltration and deformation.The predicted results of PECANN are compared with the finite difference solutions or analytical solutions.The results indicate that PECANN can accurately capture the variations of pressure head during the unsaturated infiltration,and present higher precision and robustness than DNN and PINN.It is also revealed that PECANN can achieve the same accuracy as the finite difference method with fewer initial and boundary training data.Additionally,we investigate the effect of the hyperparameters of PECANN on solving RE problem.PECANN provides an effective tool for simulating unsaturated infiltration. 展开更多
关键词 Richards equation(RE) Unsaturated infiltration Data-driven solutions Numerical modeling Machine learning(ML)
下载PDF
A dynamic soil freezing characteristic curve model for frozen soil 被引量:1
6
作者 Xiaokang Li Xu Li Jiankun Liu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第8期3339-3352,共14页
The soil freezing characteristic curve(SFCC)plays a fundamental role in comprehending thermohydraulic behavior and numerical simulation of frozen soil.This study proposes a dynamic model to uniformly express SFCCs ami... The soil freezing characteristic curve(SFCC)plays a fundamental role in comprehending thermohydraulic behavior and numerical simulation of frozen soil.This study proposes a dynamic model to uniformly express SFCCs amidst varying total water contents throughout the freezing-thawing process.Firstly,a general model is proposed,wherein the unfrozen water content at arbitrary temperature is determined as the lesser of the current total water content and the reference value derived from saturated SFCC.The dynamic performance of this model is verified through test data.Subsequently,in accordance with electric double layer(EDL)theory,the theoretical residual and minimum temperatures in SFCC are calculated to be-14.5℃to-20℃for clay particles and-260℃,respectively.To ensure that the SFCC curve ends at minimum temperature,a correction function is introduced into the general model.Furthermore,a simplified dynamic model is proposed and investigated,necessitating only three parameters inherited from the general model.Additionally,both general and simplified models are evaluated based on a test database and proven to fit the test data exactly across the entire temperature range.Typical recommended parameter values for various types of soils are summarized.Overall,this study provides not only a theoretical basis for most empirical equations but also proposes a new and more general equation to describe the SFCC. 展开更多
关键词 Frozen soils Unsaturated soils Soil freezing characteristic curve(SFCC) Mathematic models
下载PDF
Effects of Cadmium on Polar Lipid Composition and Unsaturation in Maize(Zea mays) in Hydroponic Culture 被引量:2
7
作者 Radhouane Chaffai Tinni Nouhou Seybou +1 位作者 Brahim Marzouk Ezzedine EI Ferjani 《Journal of Integrative Plant Biology》 SCIE CAS CSCD 2007年第12期1693-1702,共10页
This study aimed to evaluate the effect of Cd exposure (100 μmol/L) on polar lipid composition, and to examine the level of fatty acid unsaturation in maize (Zea mays L.). In roots, the level of 16:0 and monouns... This study aimed to evaluate the effect of Cd exposure (100 μmol/L) on polar lipid composition, and to examine the level of fatty acid unsaturation in maize (Zea mays L.). In roots, the level of 16:0 and monounsaturated fatty acids (16:1 + 18:1) decreased in phosphatidylcholine (PC) and phosphatidylethanolamine (PE). In contrast, the proportion of unsaturated 18-C fatty acid species showed an opposite response to Cd. The content, on the other hand, of PC, PE, digalactosyldiacylglycerol (DGDG), and steryl lipids increased in roots (2.9-, 1.6-, 5.3-, and 1.7-fold increase, respectively). These results suggest that a more unsaturated fatty acid composition than found in control plants with a concomitant increase in polar lipids may favor seedling growth during Cd exposure. However, the observed increase in the steryl lipid (SL) : phospholipid (PL) ratio (twofold), the decrease in monogalactosyldiacylglycerol (MGDG) : DGDG ratio, as well as the induction of lipid peroxidation in roots may represent symptoms of membrane injury. In shoots, the unsaturation level was markedly decreased in PC and phosphatidylglycerol (PG) after Cd exposure, but showed a significant increase in sulfoquinovosyldiacylglycerol (SQDG), MGDG and DGDG. The content of PG and MGDG was decreased by about 65%, while PC accumulated to higher levels (4.4-fold increase). Taken together, these changes in the polar lipid unsaturation and composition are likely to be due to alterations in the glycerolipid pathway. These results also support the idea that the increase in overall unsaturation plays some role in enabling the plant to withstand the metal exposure. 展开更多
关键词 CADMIUM fatty acids heavy metal stress lipid peroxidation polar lipids unsaturation level Zea mays.
原文传递
A thermodynamics-based three-scale constitutive model for partially saturated granular materials
8
作者 Jianqiu Tian Enlong Liu Yuancheng Guo 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第5期1813-1831,共19页
A three-scale constitutive model for unsaturated granular materials based on thermodynamic theory is presented.The three-scale yield locus,derived from the explicit yield criterion for solid matrix,is developed from a... A three-scale constitutive model for unsaturated granular materials based on thermodynamic theory is presented.The three-scale yield locus,derived from the explicit yield criterion for solid matrix,is developed from a series of discrete interparticle contact planes.The three-scale yield locus is sensitive to porosity changes;therefore,it is reinterpreted as a corresponding constitutive model without phenomenological parameters.Furthermore,a water retention curve is proposed based on special pore morphology and experimental observations.The features of the partially saturated granular materials are well captured by the model.Under wetting and isotropic compression,volumetric compaction occurs,and the degree of saturation increases.Moreover,the higher the matric suction,the greater the strength,and the smaller the volumetric compaction.Compared with the phenomenological Barcelona basic model,the proposed three-scale constitutive model has fewer parameters;virtually all parameters have clear physical meanings. 展开更多
关键词 Unsaturated granular material Unsaturated porous material GEOMATERIALS Multi-scale constitutive model Water retention curve PLASTICITY
下载PDF
Modelling the water diversion of a sustainable cover system under humid climates
9
作者 Haowen Guo Charles Wang Wai Ng +2 位作者 Qi Zhang Chuanxiang Qu Liwen Hu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第7期2429-2440,共12页
Extreme rainfall significantly threatens the safety of the landfill cover system,especially under humid climates.This study aims to provide design recommendations for a sustainable landfill cover system consisting of ... Extreme rainfall significantly threatens the safety of the landfill cover system,especially under humid climates.This study aims to provide design recommendations for a sustainable landfill cover system consisting of a low-permeability soil layer underlying a two-layer capillary barrier for humid climates.First,the numerical back-analysis was conducted for verification against a series of flume model tests.Then,a parametric study was performed to investigate the effects of inclination angle,particle size and layer thickness on the lateral diversion length(DL)of the three-layer cover system under the 100-year return period rainfall of humid climates.The results show that the water lateral DL of the cover system can be greatly enhanced by increasing the inclination angle from 3°to 18°.Moreover,the bottom layer of the cover system with a coarser d10 was more susceptible to the impact of the heavy rainfall,while this can be alleviated by increasing the thickness of the bottom layer.A dimensionless number,defined as the ratio of thickness and d_(10) of the bottom layer,is proposed for designing lateral diversion of the three-layer cover system under humid climates.To preserve the maximum DL,it is suggested that the proposed dimensionless number should be larger than 95 and 110 for the design of rainfall events with 50-year and 100-year return periods for humid climates,respectively. 展开更多
关键词 Unsaturated soil RECYCLING Construction waste Three-layer landfill cover Water infiltration
下载PDF
Experimental and numerical investigation of droplet flow mechanisms at fracture intersections
10
作者 Cao Luo Zexiong Zhou +2 位作者 Chi Yao Zhibing Yang Chuangbing Zhou 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第11期4669-4682,共14页
Understanding unsaturated flow behaviors in fractured rocks is essential for various applications.A fundamental process in this regard is flow splitting at fracture intersections.However,the impact of geometrical prop... Understanding unsaturated flow behaviors in fractured rocks is essential for various applications.A fundamental process in this regard is flow splitting at fracture intersections.However,the impact of geometrical properties of fracture intersections on flow splitting is still unclear.This work investigates the combined influence of geometry(intersection angle,fracture apertures,and inclination angle),liquid droplet length,inertia,and dynamic wetting properties on liquid splitting dynamics at fracture intersections.A theoretical model of liquid splitting is developed,considering the factors mentioned above,and numerically solved to predict the flow splitting behavior.The model is validated against carefullycontrolled visualized experiments.Our results reveal two distinct splitting behaviors,separated by a critical droplet length.These behaviors shift from a monotonic to a non-monotonic trend with decreasing inclination angle.A comprehensive analysis further clarifies the impacts of the key factors on the splitting ratio,which is defined as the percentage of liquid volume entering the branch fracture.The splitting ratio decreases with increasing inclination angle,indicating a decrease in the gravitational effect on the branch fracture,which is directly proportional to the intersection angle.A non-monotonic relationship exists between the splitting ratio and the aperture ratio of the branch fracture to the main fracture.The results show that as the intersection angle decreases,the splitting ratio increases.Additionally,the influence of dynamic contact angles decreases with increasing intersection angle.These findings enhance our understanding of the impact of geometry on flow dynamics at fracture intersections.The proposed model provides a foundation for simulating and predicting unsaturated flow in complex fractured networks. 展开更多
关键词 Fracture rock Fracture intersection Unsaturated flow Intersection angle
下载PDF
Water retention behavior and shear strength of artificially cemented granite residual soil subjected to free drying
11
作者 Xinxin Dong Xiaohua Bao +2 位作者 Hongzhi Cui Changjie Xu Xiangsheng Chen 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第11期4697-4710,共14页
Artificially cemented soils have been widely used as filling materials in highway and railway construction.The shear strength evolution of filling materials upon moist variation can determine the stability of subgrade... Artificially cemented soils have been widely used as filling materials in highway and railway construction.The shear strength evolution of filling materials upon moist variation can determine the stability of subgrade and embankments.This study conducted water retention tests,MIP tests,and multi-stage triaxial shear tests on cement-treated granite residual soil(GRS)to determine its water retention curve(WRC)upon free drying,pore structure,and peak shear strength qf,respectively.The water retention behavior and shear strength evolution upon free drying were modeled based on the dual-porosity structure of cement-treated GRS and the effective stress principle,respectively.Results show that the drying-WRC is bimodal and higher cement dosage yields a more severe decrease in the water retention capacity within a specific suction range.For a given confining pressure,the peak shear strength qf increased with increasing cement dosage or suction value s.The peak shear strength qf also solely depends on the suction value in the peak stress state.In addition,the cement-treated GRS has a bimodal pore size distribution curve,and its macro-and micro-void ratios remain almost unchanged after free drying.The bimodal drying-WRC of the cement-treated GRS can be modeled by differentiating the water retention mechanisms in macro-and micro-pores.Moreover,using the macro-pore degree of saturation as the effective stress parameterχ=S_(rM),the q_(f)–p′_(f)relationship(where p′_(f)is the effective mean pressure at failure)under various suction and stress conditions can be unified,and the q_(f)–s relationships at various net confining pressuresσ_(3),net can be well reproduced.These findings can help design subgrade and embankments constructed by artificially cemented GRS and assess their safe operation upon climate change. 展开更多
关键词 Granite residual soil Cement treatment DUAL-POROSITY Water retention behavior Unsaturated shear strength
下载PDF
An improved creep model for unsaturated reticulated red clay
12
作者 Chuang Zhang Junhui Zhang Jianzhong Li 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第11期4754-4768,共15页
Establishment of a creep model is an important method to analyze the relationship between soil creep deformation and time,and the element model is widely used for studying soil creep.However,the element creep model is... Establishment of a creep model is an important method to analyze the relationship between soil creep deformation and time,and the element model is widely used for studying soil creep.However,the element creep model is employed for fitting saturated soil,and the mechanical element model is generally linear,which cannot well fit the nonlinear deformation of the soil with time in practice.The creep process of the soil is not only time-dependent,but also related to the deviatoric stress level.Therefore,the fractional calculus theory and a parameter n reflecting the effect of deviatoric stress level on the creep properties of the soil were introduced into the element model,and the fractional qBurgers creep model was established by using the fractional Koeller dashpot and Caputo fractional calculus.The proposed model was used to fit the triaxial test data of reticulated red clay under different net confining pressures and matric suctions by unsaturated triaxial apparatus.The proposed model can well describe the nonlinearity of unsaturated reticulated red clay,has memory and global correlation to the creep development process of unsaturated reticulated red clay,and has clear physical meaning.The functional relationships of the model parameters with the matric suction,net confining pressure and deviatoric stress level were deduced,so that the creep curves of unsaturated reticulated red clay can be obtained for any conditions,which is of great value for the study of unsaturated soils. 展开更多
关键词 Fractional calculus Creep model BURGERS Parameter study Unsaturated reticulated red clay
下载PDF
Dietary cooking oils and cardiometabolic measurements in an elderly Chinese population
13
作者 Xin-Yu WANG Chao-Ying MIAO +5 位作者 Xiao-Fei YE Wen-Yuan-Yue WANG Jia-Bo ZHU Yi ZHOU Yan LI Ji-Guang WANG 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2024年第6期642-650,共9页
OBJECTIVE To investigate three features of dietary cooking oil intake,namely,the consumption,cooking style,and composition of fatty acids in relation to several cardiometabolic measurements in an elderly Chinese popul... OBJECTIVE To investigate three features of dietary cooking oil intake,namely,the consumption,cooking style,and composition of fatty acids in relation to several cardiometabolic measurements in an elderly Chinese population.METHODS The elderly(≥65 years)participants for this study were recruited from two community health centers in the urban area of Shanghai.A questionnaire was administered to collect information on dietary oil consumption(low,medium and high)and cooking styles(fry or stir-fry vs.others)and the composition of fatty acids(poly-unsaturated vs.mono-unsaturated).The cardiometabolic measurements included anthropometry,blood pressure,fasting plasma glucose and serum lipids.RESULTS The 1186 study participants had a mean age of 70.9±5.4 years.The mean dietary oil consumption was 35.0 g/d,being low(<25 g/d),medium(25-49 g/d)and high(≥50 g/d)in 485,467 and 234 participants,respectively.The proportion of the fry or stir-fry cooking style and oils rich in mono-unsaturated fatty acids was 30.4%and 27.4%,respectively.Both before and after adjustment for sex,age,current smoking and alcohol intake,dietary oil consumption was significantly(P≤0.02)and positively associated with the prevalence of treated hypertension and fasting plasma glucose concentration.With similar adjustments as above and additional adjustment for dietary oil consumption,the fry or stir-fry cooking style was significantly(P≤0.048)and positively associated with body mass index,but inversely with systolic and diastolic blood pressure and serum low-density lipoprotein cholesterol,and the dietary intake of oils rich in mono-unsaturated fat acids was significantly(P≤0.02)and positively associated with diastolic blood pressure,serum triglycerides,total cholesterol and low-density lipoprotein cholesterol,and the prevalence of hypertriglyceridemia and hypercholesterolemia.CONCLUSIONS This study showed that both the consumption and composition of fatty acids of the dietary oils mattered with regard to several cardiometabolic measurements in an elderly Chinese population. 展开更多
关键词 COOKING ELDERLY UNSATURATED
下载PDF
Wetting front migration model of ion-adsorption rare earth during the multi-hole unsaturated liquid injection
14
作者 Yu Wang Xiaojun Wang +8 位作者 Yuchen Qiu Hao Wang Gang Li Kaijian Hu Wen Zhong Zhongqun Guo Bing Li Chunlei Zhang Guangxiang Ye 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第2期483-496,共14页
In the process of ion-adsorption rare earth ore leaching,the migration characteristics of the wetting front in multi-hole injection holes and the influence of wetting front intersection effect on the migration distanc... In the process of ion-adsorption rare earth ore leaching,the migration characteristics of the wetting front in multi-hole injection holes and the influence of wetting front intersection effect on the migration distance of wetting fronts are still unclear.Besides,wetting front migration distance and leaching time are usually required to optimize the leaching process.In this study,wetting front migration tests of ionadsorption rare earth ores during the multi-hole fluid injection(the spacing between injection holes was 10 cm,12 cm and 14 cm)and single-hole fluid injection were completed under the constant water head height.At the pre-intersection stage,the wetting front migration laws of ion-adsorption rare earth ores during the multi-hole fluid injection and single-hole fluid injection were identical.At the postintersection stage,the intersection accelerated the wetting front migration.By using the Darcy’s law,the intersection effect of wetting fronts during the multi-hole liquid injection was transformed into the water head height directly above the intersection.Finally,based on the Green-Ampt model,a wetting front migration model of ion-adsorption rare earth ores during the multi-hole unsaturated liquid injection was established.Error analysis results showed that the proposed model can accurately simulate the infiltration process under experimental conditions.The research results enrich the infiltration law and theory of ion-adsorption rare earth ores during the multi-hole liquid injection,and this study provides a scientific basis for optimizing the liquid injection well pattern parameters of ion-adsorption rare earth in situ leaching in the future. 展开更多
关键词 Ion-adsorption rare earth ore Multi-hole unsaturated liquid injection In situ leaching Intersection effect Calculation model
下载PDF
Oils with different degree of saturation:effects on ileal digestibility of fat and corresponding additivity and bacterial community in growing pigs
15
作者 Lu Wang Yifan Chen +2 位作者 Yuansen Yang Nuo Xiao Changhua Lai 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2024年第4期1657-1668,共12页
Background Oils are important sources of energy in pig diets.The combination of oils with different degree of saturation contributes to improve the utilization efficiency of the mixed oils and may reduce the cost of o... Background Oils are important sources of energy in pig diets.The combination of oils with different degree of saturation contributes to improve the utilization efficiency of the mixed oils and may reduce the cost of oil supplemented.An experiment was conducted to evaluate the effects of oils with different degree of saturation on the fat digestibility and corresponding additivity and bacterial community in growing pigs.Methods Eighteen crossbred(Duroc×Landrace×Yorkshire)barrows(initial body weight:29.3±2.8 kg)were surgically fitted with a T-cannula in the distal ileum.The experimental diets included a fat-free basal diet and 5 oil-added diets.The 5 oil-added diets were formulated by adding 6%oil with different ratio of unsaturated to saturated fatty acids(U:S)to the basal diet.The 5 oils were palm oil(U:S=1.2),canola oil(U:S=12.0),and palm oil and canola oil were mixed in different proportions to prepare a combination of U:S of 2.5,3.5 and 4.5,respectively.Results The apparent and standardized ileal digestibility(AID and SID)of fat and fatty acids increased linearly(P<0.05)as the U:S of dietary oils increased except for SID of fat and C18:2.The AID and SID of fat and fatty acids differed among the dietary treatments(P<0.05)except for SID of unsaturated fatty acids(UFA)and C18:2.Fitted one-slope broken-line analyses for the SID of fat,saturated fatty acids(SFA)and UFA indicated that the breakpoint for U:S of oil was 4.14(R^(2)=0.89,P<0.01),2.91(R^(2)=0.98,P<0.01)and 3.84(R^(2)=0.85,P<0.01),respectively.The determined SID of fat,C18:1,C18:2 and UFA in the mixtures was not different from the calculated SID of fat,C18:1,C18:2 and UFA.However,the determined SID of C16:0,C18:0 and SFA in the mixtures were greater than the calculated SID values(P<0.05).The abundance of Romboutsia and Turicibacter in pigs fed diet containing palm oil was greater than that in rapeseed oil treatment group,and the two bacteria were negatively correlated with SID of C16:0,C18:0 and SFA(P<0.05).Conclusions The optimal U:S for improving the utilization efficiency of mixed oil was 4.14.The SID of fat and UFA for palm oil and canola oil were additive in growing pigs,whereas the SID of SFA in the mixture of two oils was greater than the sum of the values of pure oils.Differences in fat digestibility caused by oils differing in degree of saturation has a significant impact on bacterial community in the foregut. 展开更多
关键词 ADDITIVITY Bacterial community Fat and fatty acids Growing pigs Ratio of unsaturated to saturated fatty acids Standardized ileal digestibility
下载PDF
Effect of degree of saturation on stresses and pore water pressure in the subgrade layer caused by railway track loading
16
作者 Mohammed Y.Fattah Qutaiba G.Majeed Hassan H.Joni 《Railway Sciences》 2024年第4期413-436,共24页
Purpose-The experiments of this study investigated the effect of the subgrade degree of saturation on the value of the stresses generated on the surface and the middle(vertical and lateral stresses).The objectives of ... Purpose-The experiments of this study investigated the effect of the subgrade degree of saturation on the value of the stresses generated on the surface and the middle(vertical and lateral stresses).The objectives of this study can be identified by studying the effect of subgrade layer degree of saturation variation,load amplitude and load frequency on the transmitted stresses through the ballast layer to the subgrade layer and the stress distribution inside it and investigating the excess pore water pressure development in the clay layer in the case of a fully saturated subgrade layer and the change in matric suction in the case of an unsaturated subgrade layer.Design/methodology/approach-Thirty-six laboratory experiments were conducted using approximately half-scale replicas of real railways,with an iron box measuring 1.5×1.031.0 m.Inside the box,a 0.5 m thick layer of clay soil representing the base layer was built.Above it is a 0.2 m thick ballast layer made of crushed stone,and on top of that is a 0.8 m long rail line supported by three 0.9 m(0.1×0.1 m)slipper beams.The subgrade layer has been built at the following various saturation levels:100,80,70 and 60%.Experiments were conducted with various frequencies of 1,2 and 4 Hz with load amplitudes of 15,25 and 35 kN.Findings-The results of the study demonstrated that as the subgrade degree of saturation decreased from 100 to 60%,the ratio of stress in the lateral direction to stress in the vertical direction generated in the middle of the subgrade layer decreased as well.On average,this ratio changed from approximately 0.75 to approximately 0.65.Originality/value-The study discovered that as the test proceeded and the number of cycles increased,the value of negative water pressure(matric suction)in the case of unsaturated subgrade soils declined.The frequency of loads had no bearing on the ratio of decline in matric suction values,which was greater under a larger load amplitude than a lower one.As the test progressed(as the number of cycles increased),the matric suction dropped.For larger load amplitudes,there is a greater shift in matric suction.The change in matric suction is greater at higher saturation levels than it is at lower saturation levels.Furthermore,it is seen that the load frequency value has no bearing on how the matric suction changes.For all load frequencies and subgrade layer saturation levels,the track panel settlement rises with the load amplitude.Higher load frequency and saturation levels have a greater impact. 展开更多
关键词 Subgrade clay UNSATURATED TRACK Matric suction Stresses
下载PDF
Serum bile acid and unsaturated fatty acid profiles of non-alcoholic fatty liver disease in type 2 diabetic patients
17
作者 Su-Su Feng Si-Jing Wang +8 位作者 Lin Guo Pan-Pan Ma Xiao-Long Ye Ming-Lin Pan Bo Hang Jian-Hua Mao Antoine M Snijders Yi-Bing Lu Da-Fa Ding 《World Journal of Diabetes》 SCIE 2024年第5期898-913,共16页
BACKGROUND The understanding of bile acid(BA)and unsaturated fatty acid(UFA)profiles,as well as their dysregulation,remains elusive in individuals with type 2 diabetes mellitus(T2DM)coexisting with non-alcoholic fatty... BACKGROUND The understanding of bile acid(BA)and unsaturated fatty acid(UFA)profiles,as well as their dysregulation,remains elusive in individuals with type 2 diabetes mellitus(T2DM)coexisting with non-alcoholic fatty liver disease(NAFLD).Investigating these metabolites could offer valuable insights into the pathophy-siology of NAFLD in T2DM.AIM To identify potential metabolite biomarkers capable of distinguishing between NAFLD and T2DM.METHODS A training model was developed involving 399 participants,comprising 113 healthy controls(HCs),134 individuals with T2DM without NAFLD,and 152 individuals with T2DM and NAFLD.External validation encompassed 172 participants.NAFLD patients were divided based on liver fibrosis scores.The analytical approach employed univariate testing,orthogonal partial least squares-discriminant analysis,logistic regression,receiver operating characteristic curve analysis,and decision curve analysis to pinpoint and assess the diagnostic value of serum biomarkers.RESULTS Compared to HCs,both T2DM and NAFLD groups exhibited diminished levels of specific BAs.In UFAs,particular acids exhibited a positive correlation with NAFLD risk in T2DM,while theω-6:ω-3 UFA ratio demonstrated a negative correlation.Levels ofα-linolenic acid andγ-linolenic acid were linked to significant liver fibrosis in NAFLD.The validation cohort substantiated the predictive efficacy of these biomarkers for assessing NAFLD risk in T2DM patients.CONCLUSION This study underscores the connection between altered BA and UFA profiles and the presence of NAFLD in individuals with T2DM,proposing their potential as biomarkers in the pathogenesis of NAFLD. 展开更多
关键词 Bile acid Non-alcoholic fatty liver disease Type 2 diabetes mellitus Unsaturated fatty acid
下载PDF
Effects of fatty acid chain length and degree of unsaturation on the surface activities of monoacyl trehaloses
18
作者 Yue-E SUN Wenshui XIA +2 位作者 Xueyan TANG Zhiyong HE Jie CHEN 《Frontiers of Chemical Science and Engineering》 SCIE EI CSCD 2009年第4期407-412,共6页
The surface properties of monoacyl trehaloses with different acyl chains were investigated at 30℃,40℃,50℃,and 60℃.Monoacyl trehaloses were enzymatically synthesized and purified with silica gel column chromatograp... The surface properties of monoacyl trehaloses with different acyl chains were investigated at 30℃,40℃,50℃,and 60℃.Monoacyl trehaloses were enzymatically synthesized and purified with silica gel column chromatography and semi-preparative high-performance liquid chromatography(HPLC),and the purity of products was identified by mass spectrometry(MS)and nuclear magnetic resonance(NMR).The surface tension of monoacyl trehalose in pure water was measured using Doüy ring method at different temperatures.The critical micelle concentrations(CMC),surface tension at the CMC,γCMC,and residual area per molecule,a,were estimated from the curves.The CMC value of unsaturated monoacyl trehalose was affected by both the degree of unsaturation and the acyl chain length,and the effect of chain length on the CMC value was much stronger than that of the unsaturation degree.However,there was no significant dependency of theγCMC value and a values on the chain length or the unsaturated degree. 展开更多
关键词 monoacyl trehalose surface properties degree of unsaturation critical micelle concentration
原文传递
Thermal-water-salt coupling process of unsaturated saline soil under unidirectional freezing 被引量:3
19
作者 LUO Chong-liang YU Yun-yan +3 位作者 ZHANG Jing TAO Jing-yan OU Qing-jie CUI Wen-hao 《Journal of Mountain Science》 SCIE CSCD 2023年第2期557-569,共13页
Salinization and desertification are closely related to water-salt migration caused by a temperature gradient.Based on the Darcy Law of unsaturated soils,the law of energy conservation and the law of mass conservation... Salinization and desertification are closely related to water-salt migration caused by a temperature gradient.Based on the Darcy Law of unsaturated soils,the law of energy conservation and the law of mass conservation,the thermal-water-salt coupling mathematical model of unsaturated frozen saline soil was established.The model considered the latent heat of phase change,crystallization impedance,crystallization consumption and complete precipitation of solute crystallization in ice.In order to verify the rationality of the model,the unidirectional freezing test of unsaturated saline soil was carried out in an open system with no-pressure water supplement to obtain the spatial distribution of temperature,moisture and salt in the saline soil.Finally,numerical simulations are implemented with the assistance of COMSOL Multiphysics.Validation of the model is illustrated by comparisons between the simulation and experimental data.The results demonstrated that the temperature within saline soil changes with time and can be divided into three stages,namely quick freezing stage,transitional stage and stable stage.The water and salt contents in the freezing zone are layered,with peak values at the freezing front.The coupled model could reveal the heat-mass migration mechanism of unsaturated frozen saline soil and dynamically describe the freezing depth and the movement law of the freezing front,ice and salt crystal formation mechanism,and the change law of thermal conductivity and permeability coefficient. 展开更多
关键词 Unsaturated sulfate saline soil Watersalt migration Crystallization latent heat Crystallization impedance Mathematical model
下载PDF
Two-dimensional plane strain consolidation of unsaturated soils considering the depth-dependent stress 被引量:1
20
作者 Lei Wang Sidong Shen +2 位作者 Tianyi Li Minjie Wen Annan Zhou 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2023年第6期1603-1614,共12页
In practical engineering,the total vertical stress in the soil layer is not constant due to stress diffusion,and varies with time and depth.Therefore,the purpose of this paper is to investigate the effect of stress di... In practical engineering,the total vertical stress in the soil layer is not constant due to stress diffusion,and varies with time and depth.Therefore,the purpose of this paper is to investigate the effect of stress diffusion on the two-dimensional(2D)plane strain consolidation properties of unsaturated soils when the stress varies with time and depth.A series of semi-analytical solutions in terms of excess pore air and water pressures and settlement for 2D plane strain consolidation of unsaturated soils can be derived with the joint use of Laplace transform and Fourier sine series expansion.Then,the inverse Laplace transform of the semi-analytical solution is given in the time domain using a self-programmed code based on Crump’s method.The reliability of the obtained solutions is proved by the degeneration.Finally,the 2D plots of excess pore pressures and the curves of settlement varying with time,considering different physical parameters of unsaturated soil stratum and depth-dependent stress,are depicted and analyzed to study the 2D plane strain consolidation properties of unsaturated soils subjected to the depthdependent stress. 展开更多
关键词 Semi-analytical solutions Two-dimensional(2D)plane strain CONSOLIDATION Unsaturated soils Depth-dependent stress Laplace transform
下载PDF
上一页 1 2 20 下一页 到第
使用帮助 返回顶部