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Behavior of steel fiber–reinforced high-strength concrete at medium strain rate

Chujie JIAO, Wei SUN, Shi HUAN, Guoping JIANG

《结构与土木工程前沿（英文）》 2009年 第3卷 第2期   页码 131-136 doi: 10.1007/s11709-009-0027-0

摘要： Impact compression experiments for the steel fiber–reinforced high-strength concrete (SFRHSC) at medium strain rate were conducted using the split Hopkinson press bar (SHPB) testing method. The volume fractions of steel fibers of SFRHSC were between 0 and 3%. The experimental results showed that, when the strain rate increased from threshold value to 90 s , the maximum stress of SFRHSC increased about 30%, the elastic modulus of SFRHSC increased about 50%, and the increase in the peak strain of SFRHSC was 2-3 times of that in the matrix specimen. The strength and toughness of the matrix were improved remarkably because of the superposition effect of the aggregate high-strength matrix and steel fiber high-strength matrix. As a result, under impact loading, cracks developed in the SFRHSC specimen, but the overall shape of the specimen remained virtually unchanged. However, under similar impact loading, the matrix specimens were almost broken into small pieces.

关键词： steel fiber–reinforced high-strength concrete (SFRHSC)     high strain rates     split Hopkinson press bar (SHPB)     strain rate hardening effects    

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Microbial community dynamics at high organic loading rates revealed by pyrosequencing during sugar refinery

Liguo Zhang, Qiaoying Ban, Jianzheng Li

《环境科学与工程前沿（英文）》 2018年 第12卷 第4期 doi: 10.1007/s11783-018-1045-8

摘要：

High strength sugar refinery wastewater was treated in a mesophilic UASB.

Pyrosequencing reveals microbial community succession with OLR increase.

Diversity of microbial communities in OLR12 is much higher than those in OLR36 and OLR54.0 kgCOD/(kg VSS·d).

Fermentative bacteria could deal with increasing OLR through the increase of microbial diversity and quantity.

Hydrogen-producing acotogens and methanogens mainly coped with high OLR shocks by increasing the quantity of community

关键词： Upflow anaerobic sludge blanket     Sugar refinery wastewater     Organic loading rate     Pyrosequencing     Microbial community structure    

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Fictitious soil pile model for dynamic analysis of pipe piles under high-strain conditions

《结构与土木工程前沿（英文）》   页码 915-934 doi: 10.1007/s11709-023-0907-8

摘要： A fictitious soil pile (FSP) model is developed to simulate the behavior of pipe piles with soil plugs undergoing high-strain dynamic impact loading. The developed model simulates the base soil with a fictitious hollow pile fully filled with a soil plug extending at a cone angle from the pile toe to the bedrock. The friction on the outside and inside of the pile walls is distinguished using different shaft models, and the propagation of stress waves in the base soil and soil plug is considered. The motions of the pile−soil system are solved by discretizing them into spring-mass model based on the finite difference method. Comparisons of the predictions of the proposed model and conventional numerical models, as well as measurements for pipe piles in field tests subjected to impact loading, validate the accuracy of the proposed model. A parametric analysis is conducted to illustrate the influence of the model parameters on the pile dynamic response. Finally, the effective length of the FSP is proposed to approximate the affected soil zone below the pipe pile toe, and some guidance is provided for the selection of the model parameters.

关键词： fictitious soil pile     soil plug     pipe piles     high-strain dynamic analysis     one-dimensional wave theory     pile dynamics    

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Preparation of reverse osmosis membrane with high permselectivity and anti-biofouling properties for

《环境科学与工程前沿（英文）》 2022年 第16卷 第7期 doi: 10.1007/s11783-021-1497-0

摘要：

• Nanoparticle incorporation and anti-biofouling grafting were integrated.

关键词： Anti-biofouling grafting     Nanoparticle incorporation     Sterilization rates     Water flux     Water flux recovery    

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Relationships between loading rates and nitrogen removal effectiveness in subsurface flow constructed

ZHANG Rongshe, LI Guanghe, ZHANG Xu, ZHOU Qi

《环境科学与工程前沿（英文）》 2008年 第2卷 第1期   页码 89-93 doi: 10.1007/s11783-008-0002-3

摘要： Nitrogen removal of wetlands under 40 different inflow loadings were studied in the field during 15 months. The removal efficiency of four different sets of beds, namely the reed bed, the Zizania caduciflor bed, the mixing planting bed, and the control bed were studied. The outflow loading and total nitrogen (TN) removal rate of these beds under different inflow loadings and pollution loadings were investigated. The inflow loadings of 4 sub-surface flow systems (SFS) ranged from 400 to 8000 mg·(m·d), while outflow loadings were less than 7000 mg·(m·d). The results showed that the inflow and outflow loading of TN removal rate in SFS presented an obvious linear relationship. The optical inflow loading to run the system was between 2000 to 4000 mg·(m·d). Average removal rate was between 1062 and 2007 mg·(m·d). SFS with plant had a better removal rate than the control. TN removal rates of the reed and Zizania caduciflora bed were 63% and 27% higher than the control bed, respectively. The results regarding the TN absorption of plants indicated that the absorption amount was very limited, less than 5% of the total removal. It proved that plants clearly increase TN removal rates by improving the water flow, and increasing the biomass, as well as activities of microorganisms around the roots. The research provided a perspective for understanding the TN removal mechanism and design for SFS.
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LCF behavior and life prediction method of a single crystal nickel-based superalloy at high temperature

Zhihua ZHANG,Huichen YU,Chengli DONG

《机械工程前沿（英文）》 2015年 第10卷 第4期   页码 418-423 doi: 10.1007/s11465-015-0362-x

摘要：

Low cycle fatigue tests were conducted on the single crystal nickel-based superalloy, DD6, with different crystallographic orientations (i.e., [001], [011], and [111]) and strain dwell types (i.e., tensile, compressive, and balanced types) at a certain high temperature. Given the material anisotropy and mean stress, both orientation factor and stress range were introduced to the Smith, Watson, and Topper (SWT) stress model to predict the fatigue life. Experimental results indicated that the fatigue properties of DD6 depend on both crystallographic orientation and loading types. The fatigue life of the tensile, compressive, and balanced strain dwell tests are shorter than those of continuous cycling tests without strain dwell because of the important creep effect. The predicted results of the proposed modified SWT stress method agree well with the experimental data.

关键词： life prediction     single crystal superalloy     low cycle fatigue (LCF)     crystallographic orientation     strain dwell    

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Concepts and implementation of strain-based criteria in design codes for steel structures

Reidar BJORHOVDE

《结构与土木工程前沿（英文）》 2012年 第6卷 第3期   页码 210-216 doi: 10.1007/s11709-012-0165-7

摘要： A uniaxial tension test is commonly used to determine the mechanical properties of steel, but it has no meaning for the response of the material in a structure. The test was developed as a consensus solution by producers, fabricators, designers and code writers, to have a standard by which similar materials could be compared to a common base. It does not represent the actual behavior of the steel in a structure, and was never intended to do so. To study the true behavior of the structure and how the material responds it would be better to determine the strains and deformations that will take place during actual service condition. Such characteristics reflect the real behavior, whether in the elastic or inelastic range. If stresses or forces are needed, these are easily determined by the value of the strain and the relevant material modulus, along with the type of cross section, whether elastic or inelastic. The paper addresses the properties of a range of structural steels, how these are incorporated into design standards and how the standards define deformation characteristics and demands for bolted and welded connections.

关键词： steel     stress-strain characteristics     tension test     strain design     actual behavior     improved design codes    

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new antitranspirant on the physiology and water use efficiency of soybean under different irrigation rates

Shasha JI, Ling TONG, Fusheng LI, Hongna LU, Sien LI, Taisheng DU, Youjie WU

《农业科学与工程前沿（英文）》 2017年 第4卷 第2期   页码 155-164 doi: 10.15302/J-FASE-2017148

摘要： Antitranspirants are exogenous substances applied to leaves to reduce luxury transpiration by regulating stomatal conductance to increase water use efficiency (WUE). A cheap and environmentally-friendly antitranspirant, FZ, was newly developed, extracted mainly from . Its effects on soybean water use were investigated in a field experiment using the locally-used irrigation rate and a low irrigation rate (The lower and upper limit of irrigation is 40%–70% of field capacity). Foliar application of FZ and measurement of leaf physiological characteristics, final biomass, seed yield and water use efficiency were carried out during the pod bearing and pod filling stages of drip-irrigated soybean with film-mulching. Under the low irrigation rate, leaf stomatal conductance (g ) and transpiration rate (Tr) decreased significantly by 7 d after spraying, but photosynthesis (Pn) and instantaneous water use efficiency (WUE ) were not significantly affec ted. The stomatal frequency, stomatal aperture, g , Tr and Pn decreased by 1 d after spraying, without significantly increasing WUE . However, applying FZ during the pod bearing and pod filling stages did not significantly affect the final biomass, water consumption, seed yield and WUE of soybean. Under the locally-used irrigation rate, applying FZ increased the activities of superoxide dismutase and peroxidase in the leaves by 38% and 33%, respectively, but did not significantly affect g , Tr, Pn, stomatal aperture and stomatal frequency. Applying FZ three times during pod bearing and pod filling stages enhanced seed yield and WUE by 24% and 21%, respectively, but did not significantly affect the final biomass and water consumption. Therefore, seed yield and WUE of soybean were significantly increased by foliar application of FZ during the pod bearing and pod filling stages under the locally-used irrigation rate in arid region, but applying FZ did not have a positive effect on water use efficiency of soybean under a low irrigation rate.

关键词： antitranspirant     soybean     water deficit     leaf gas exchange     enzymes activities     water consumption     seed yield    

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Achieving High Strength and Tensile Ductility in Pure Nickel by Cryorolling with Subsequent Low-Temperature

Zhide Li,Hao Gu,Kaiguang Luo,Charlie Kong,Hailiang Yu,

《工程（英文）》 doi: 10.1016/j.eng.2023.01.019

摘要： ty. In this study, cryorolling under different strains followed by low-temperature short-time annealing was used to fabricate pure nickel sheets combining high strength with good ductility. The results show that, for different cryorolling strains, the uniform elongation was greatly increased without sacrificing the strength after annealing. A yield strength of 607 MPa and a uniform elongation of 11.7% were obtained after annealing at a small cryorolling strain (ε = 0.22), while annealing at a large cryorolling strain (ε = 1.6) resulted in a yield strength of 990 MPa and a uniform elongation of 6.4%. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and electron backscattered diffraction (EBSD) were used to characterize the microstructure of the specimens and showed that the high strength could be attributed to strain hardening during cryorolling, with an additional contribution from grain refinement and the formation of dislocation walls. The high ductility could be attributed to annealing twins and micro-shear bands during stretching, which improved the strain hardening capacity. The results show that the synergistic effect of strength and ductility can be regulated through low-temperature short-time annealing with different cryorolling strains, which provides a new reference for the design of future thermo-mechanical processes.

关键词： Cryorolling     Annealing     Nickel     Strain hardening     Ductility    

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Full-field dynamic strain reconstruction of an aero-engine blade from limited displacement responses

《机械工程前沿（英文）》 2023年 第18卷 第1期 doi: 10.1007/s11465-022-0731-1

摘要： Blade strain distribution and its change with time are crucial for reliability analysis and residual life evaluation in blade vibration tests. Traditional strain measurements are achieved by strain gauges (SGs) in a contact manner at discrete positions on the blades. This study proposes a method of full-field and real-time strain reconstruction of an aero-engine blade based on limited displacement responses. Limited optical measured displacement responses are utilized to reconstruct the full-field strain. The full-field strain distribution is in-time visualized. A displacement-to-strain transformation matrix is derived on the basis of the blade mode shapes in the modal coordinate. The proposed method is validated on an aero-engine blade in numerical and experimental cases. Three discrete vibrational displacement responses measured by laser triangulation sensors are used to reconstruct the full-field strain over the whole operating time. The reconstructed strain responses are compared with the results measured by SGs and numerical simulation. The high consistency between the reconstructed and measured results demonstrates the accurate strain reconstructed by the method. This paper provides a low-cost, real-time, and visualized measurement of blade full-field dynamic strain using displacement response, where the traditional SGs would fail.

关键词： aero-engine blade     displacement response     dynamic strain reconstruction     mode shape     strain gauge    

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Strain and process engineering toward continuous industrial fermentation

《化学科学与工程前沿（英文）》 2023年 第17卷 第10期   页码 1336-1353 doi: 10.1007/s11705-022-2284-6

摘要： Most current biotechnology industries are based on batch or fed-batch fermentation processes, which often show low productivity and high production costs compared to chemical processes. To increase the economic competitiveness of biological processes, continuous fermentation technologies are being developed that offer significant advantages in comparison with batch/fed-batch fermentation processes, including: (1) removal of potential substrates and product inhibition, (2) prolonging the microbial exponential growth phase and enhancing productivity, and (3) avoiding repeated fermentation preparation and lowering operation and installation costs. However, several key challenges should be addressed for the industrial application of continuous fermentation processes, including (1) contamination of the fermentation system, (2) degeneration of strains, and (3) relatively low product titer. In this study, we reviewed and discussed metabolic engineering and synthetic biology strategies to address these issues.

关键词： continuous fermentation     productivity     contamination     strain degeneration     metabolic engineering    

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Vibration analysis of nano-structure multilayered graphene sheets using modified strain gradient theory

Amir ALLAHBAKHSHI,Masih ALLAHBAKHSHI

《机械工程前沿（英文）》 2015年 第10卷 第2期   页码 187-197 doi: 10.1007/s11465-015-0339-9

摘要：

In this paper, for the first time, the modified strain gradient theory is used as a new size-dependent Kirchhoff micro-plate model to study the effect of interlayer van der Waals (vdW) force for the vibration analysis of multilayered graphene sheets (MLGSs). The model contains three material length scale parameters, which may effectively capture the size effect. The model can also degenerate into the modified couple stress plate model or the classical plate model, if two or all of the material length scale parameters are taken to be zero. After obtaining the governing equations based on modified strain gradient theory via principle of minimum potential energy, as only infinitesimal vibration is considered, the net pressure due to the vdW interaction is assumed to be linearly proportional to the deflection between two layers. To solve the governing equation subjected to the boundary conditions, the Fourier series is assumed for w=w(x, y). To show the accuracy of the formulations, present results in specific cases are compared with available results in literature and a good agreement can be seen. The results indicate that the present model can predict prominent natural frequency with the reduction of structural size, especially when the plate thickness is on the same order of the material length scale parameter.

关键词： graphene     van der Waals (vdW) force     modi- fied strain gradient elasticity theory     size effect parameter    

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FEM-based strain analysis study for multilayer sheet forming process

Rongjing ZHANG,Lihui LANG,Rizwan ZAFAR

《机械工程前沿（英文）》 2015年 第10卷 第4期   页码 373-379 doi: 10.1007/s11465-015-0371-9

摘要：

Fiber metal laminates have many advantages over traditional laminates (e.g., any type of fiber and resin material can be placed anywhere between the metallic layers without risk of failure of the composite fabric sheets). Furthermore, the process requirements to strictly control the temperature and punch force in fiber metal laminates are also less stringent than those in traditional laminates. To further explore the novel method, this study conducts a finite element method-based (FEM-based) strain analysis on multilayer blanks by using the 3A method. Different forming modes such as wrinkling and fracture are discussed by using experimental and numerical studies. Hydroforming is used for multilayer forming. The Barlat 2000 yield criteria and DYNAFORM/LS-DYNA are used for the simulations. Optimal process parameters are determined on the basis of fixed die-binder gap and variable cavity pressure. The results of this study will enhance the knowledge on the mechanics of multilayer structures formed by using the 3A method and expand its commercial applications.

关键词： finite element method (FEM)     strain analysis     multilayer sheet forming    

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Correlation between serum miR-154-5p and urinary albumin excretion rates in patients with type 2 diabetes

Huiwen Ren, Can Wu, Ying Shao, Shuang Liu, Yang Zhou, Qiuyue Wang

《医学前沿（英文）》 2020年 第14卷 第5期   页码 642-650 doi: 10.1007/s11684-019-0719-3

摘要： This study aimed to investigate the correlation between serum miR-154-5p and urinary albumin to creatinine ratio (UACR) in patients with type 2 diabetes mellitus (T2DM) and the association with biomarkers of inflammation and fibrosis in diabetic kidney disease (DKD). A total of 390 patients with T2DM were divided into three groups: normal albuminuria (UACR<30 mg/g, =136, NA), microalbuminuria (UACR at 30–300 mg/g, =132, MA), and clinical albuminuria (UACR>300 mg/g, =122, CA). Circulating miR-154-5p, inflammatory (C-reactive protein (CRP); erythrocyte sedimentation rate (ESR); and tumor necrosis factor-α (TNF-α) and fibrotic markers (vascular endothelial growth factor (VEGF); transforming growth factor-β1 (TGF-β1); and fibronectin (FN)), and other biochemical indicators were assessed via real-time PCR, enzyme-linked immunosorbent assay, and chemiluminescence assay in patients with T2DM and 138 control subjects (NC). UACR, miR-154-5p, glycated hemoglobin (HbA1c), serum creatinine (sCr), blood urea nitrogen (BUN), ESR, CRP, VEGF, TNF-α, TGF-β1, and FN were significantly higher and the estimated glomerular filtration rate (eGFR) was significantly lower in NA, MA, and CA groups than in NC subjects ( <0.05). Elevated levels of UACR and miR-154-5p were directly correlated with HbA1c, sCr, BUN, ESR, CRP, VEGF, TNF-α, TGF-β1, and FN and negatively correlated with eGFR ( <0.05). miR-154-5p, HbA1c, sCr, BUN, eGFR, ESR, CRP, VEGF, TNF-α, TGF-β1, and FN were important factors affecting UACR. These findings indicated that elevated serum miR-154-5p is significantly correlated with high UACR in patients with T2DM and may offer a novel reference for the early diagnosis of DKD.

关键词： type 2 diabetes mellitus     diabetic kidney disease     miR-154-5p     urinary albumin to creatinine ratio    

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Stress-strain relationship of concrete in freeze-thaw environment

ZOU Chaoying, ZHAO Juan, LIANG Feng

《结构与土木工程前沿（英文）》 2008年 第2卷 第2期   页码 184-188 doi: 10.1007/s11709-008-0029-3

摘要： Adopting the ASTM C666 quick freeze-thaw method, freeze-thaw tests with the number of freeze-thaw cycles being 0, 100, 150, 200, 250, and 300, were carried out on eighteen concrete prism specimens, the frost-resistant level of which, reaches D300 grade. The internal micro-structures of these specimens were observed by means of scanning electron microscopy (SEM) in order to detect damages caused by the freeze-thaw action. Afterwards these frozen-thawed specimens were tested on monotonic axial load; stress-strain testing curves after the freeze-thaw action were obtained. The testing results show that with the increasing time of freeze-thaw cycles, both the internal micro-structures and the basic mechanical parameters, including the ultimate bearing capacity, the Poisson ratio and the modulus of elasticity, degenerate in various degrees. Finally, stress-strain theoretical curvilinear equations and correlated parameters relating to the loss of relative dynamic modulus of elasticity were proposed. These results provide great reference for further research on the behavior and the calculation model of concrete structures in a freeze-thaw environment.

关键词： stress-strain theoretical     freeze-thaw     capacity     reference     eighteen concrete    

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标题 作者 时间 类型 操作

Behavior of steel fiber–reinforced high-strength concrete at medium strain rate

Chujie JIAO, Wei SUN, Shi HUAN, Guoping JIANG

期刊论文

Microbial community dynamics at high organic loading rates revealed by pyrosequencing during sugar refinery

Liguo Zhang, Qiaoying Ban, Jianzheng Li

期刊论文

Fictitious soil pile model for dynamic analysis of pipe piles under high-strain conditions

期刊论文

Preparation of reverse osmosis membrane with high permselectivity and anti-biofouling properties for

期刊论文

Relationships between loading rates and nitrogen removal effectiveness in subsurface flow constructed

ZHANG Rongshe, LI Guanghe, ZHANG Xu, ZHOU Qi

期刊论文

LCF behavior and life prediction method of a single crystal nickel-based superalloy at high temperature

Zhihua ZHANG,Huichen YU,Chengli DONG

期刊论文

Concepts and implementation of strain-based criteria in design codes for steel structures

Reidar BJORHOVDE

期刊论文

new antitranspirant on the physiology and water use efficiency of soybean under different irrigation rates

Shasha JI, Ling TONG, Fusheng LI, Hongna LU, Sien LI, Taisheng DU, Youjie WU

期刊论文

Achieving High Strength and Tensile Ductility in Pure Nickel by Cryorolling with Subsequent Low-Temperature

Zhide Li,Hao Gu,Kaiguang Luo,Charlie Kong,Hailiang Yu,

期刊论文

Full-field dynamic strain reconstruction of an aero-engine blade from limited displacement responses

期刊论文

Strain and process engineering toward continuous industrial fermentation

期刊论文

Vibration analysis of nano-structure multilayered graphene sheets using modified strain gradient theory

Amir ALLAHBAKHSHI,Masih ALLAHBAKHSHI

期刊论文

FEM-based strain analysis study for multilayer sheet forming process

Rongjing ZHANG,Lihui LANG,Rizwan ZAFAR

期刊论文

Correlation between serum miR-154-5p and urinary albumin excretion rates in patients with type 2 diabetes

Huiwen Ren, Can Wu, Ying Shao, Shuang Liu, Yang Zhou, Qiuyue Wang

期刊论文

Stress-strain relationship of concrete in freeze-thaw environment

ZOU Chaoying, ZHAO Juan, LIANG Feng

期刊论文