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Hydration, microstructure and autogenous shrinkage behaviors of cement mortars by addition of superabsorbent polymers

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Frontiers of structural and civil Engineering 2020年第5期14卷 1274-1284页

作者： Beibei sUN Hao wu Weimin sONG Zhe LI Jia YU school of civil Engineering Central South UniversityChangsha 410075China Magnel Laboratory for concrete Research Department of Structural EngineeringGhent UniversityGhent 9052Belgium National Engineering Laboratory for High speed Railway construction Central South UniversityChangsha 410075China

superabsorbent Polymer(sAP)has emerged as a topic of considerable interest in recent *** present study systematically and quantitively investigated the effect of sAP on hydration,autogenous shrinkage,mechanical properties,and microstructure of cement *** of sAP on hydration heat and autogenous shrinkage were studied by utilizing TAM AIR technology and a non-contact autogenous shrinkage test *** Electron Microscope(sEM)was employed to assess the microstructure *** sAP decreased the peak rate of hydration heat and retarded the hydration,it significantly increased the cumulative heat,indicating sAP helps promote the *** promotion caused by sAP mainly occurred in the deceleration period and attenuation *** can significantly mitigate the autogenous shrinkage when the content ranged from 0 to 0.5%.Microstructure characteristics showed that pores and gaps were introduced when sAP was *** microstructure difference caused by sAP contributed to the inferior mechanical behaviors of cement mortars treated by sAP.

关键词： superabsorbent Polymer mechanical properties hydration heat autogenous shrinkage microstructure

A Thermo-Tunable Metamaterial as an Actively controlled Broadband Absorber

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Engineering 2023年第1期20卷 143-152页

作者： Xiao-chang Xing Yang cao Xiao-Yong Tian Lingling wu state Key Laboratory for Manufacturing systems Engineering Xi’an Jiaotong UniversityXi’an 710049China

Metamaterials have attracted increasing attention in recent years due to their powerful abilities in manipulating electromagnetic (EM) waves. However, most previously reported metamaterials are unable to actively control full-band EM waves. In this paper, we propose a thermo-tunable broadband metamaterial (T-TBM) using paraffin-based composites (PD-cs) with different phase transition temperatures. Active control of the T-TBM reflection loss peaks from low to high frequency is realized by manipulating the solid–liquid state of the PD-cs at different phase transition temperatures. The absorption peak bandwidth (where the reflection loss value is less than −30 dB) can be changed, while the broad bandwidth absorption (where the reflection loss value is less than −10 dB) is satisfied by adjusting the temperature of the T-TBM. It is shown that the stagnation of the phase transition temperature of the PD-cs in the T-TBM provides a time window for actively controlling the EM wave absorption response under different thermal conditions. The device has a broad application prospect in the fields of EM absorption, intelligent metamaterials, multifunctional structural devices, and more.

关键词： Metamaterials Active control Thermally tunable Br oadband absorption

Reproductive toxicity of enrofloxacin in caenorhabditis elegans involves oxidative stress-induced cell apoptosis

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Journal of Environmental sciences 2023年第5期127卷 726-737页

作者： Jiahao Huang Lizi Liao Guowei Wang Zhongkun Du Zhengxing wu Key Laboratory of Molecular Biophysics Ministry of EducationCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhan 430074China school of Environmental Ecology and Biological Engineering Wuhan Institute of TechnologyWuhan 430205China Key Laboratory of Green chemical Engineering Process of Ministry of Education Wuhan 430205China college of Resources and Environment Shandong Agricultural UniversityTaian 271018China

Fluoroquinolone antibiotics(FQs)that persist and bioaccumulate in the environment have aroused people’s great ***,we studied the adverse effects of FQs in soil animals of caenorhabditis elegans via food-chronically *** result shows *** exposed to FQs exhibited reproductive toxicity with small-brood size and low-egg *** study the underlying mechanism,we conduct a deep investigation of enrofloxacin(ENR),one of the most frequently detected FQs,on nematodes which is one of commonly used animal indicator of soil *** concentration-effect curves simulated by the Hill model showed that the half effect concentrations(Ec50)of ENR were(494.3±272.9)μmol/kg and(107.4±30.9)μmol/kg for the brood size and the hatchability,*** gene expression between the control and the ENR-exposure group enriched with the oxidative stress and cell apoptosis *** results together with the enzyme activity in oxidative stress and the cell corpses suggested that ENR-induced reproductive toxicity was related to germ cell apoptosis under oxidative *** risk quotients of some soil and livestock samples were calculated based on the threshold value of Ec10 for the egg hatchability(2.65μmol/kg).The results indicated that there was possible reproductive toxicity on the nematodes in certain agricultural soils for the *** study suggested that chronic exposure to FQs at certain levels in environment would induce reproductive toxicity to the nematodes and might reduce the soil sustainability,alarming the environment risks of antibiotics abuse.

关键词： Environmental toxicity Nematodes chronic exposure Oxidative stress response Germ cell apoptosis

simulation and experimental study on the surface morphology and energy lost of the target material under non-overlapping impact of angular particles

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chinese Journal of chemical Engineering 2021年第1期34卷 47-56页

作者： Xuewen cao chenyang Fu Zhenqiang Xie chao wu Xiaoyang sun college of Pipeline and civil Engineering China University of Petroleum(East China)No.66West Changjiang RoadHuangdao DistrictQingdao 266580China

In order to further understand the effect of solid impurities on pipeline wall during erosion,the particle impact process without fluid was extracted for specific *** effect of multi-impact particles on the wall of pipeline was studied experimentally and *** this experiment,an improved ejection apparatus was implemented to carry out multi-impacts non-overlapping impingement by rhombic particles made of high speed steel(W18cr4V)on the AA6061 aluminum alloy plate through changing particle angle,incident angle,orientation angle and impact *** a result,each particle's penetration depth was investigated and particles' rebound trajectory can be described through this experiment as well as surface morphology of the target material after *** ductile damage criterion,shear damage criterion and MsFLD damage criterion were jointly implemented in ABAQUs/cAE software to simulate the whole process of collision which proved to be effective by getting consistent result compared with experimental *** is found that under the condition of continuous non-overlapping impact,the target material produces a small work hardening effect in the impact area by converting kinetic energy of moving particles into internal energy of plate so as to reduce the penetration depth of each impact particle.

关键词： Multi-impact experiment Angular particle surface morphology Energy lost ABAQUs/cAE simulation

Multistage serrated flow behavior of a medium-manganese high-carbon steel

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Journal of Iron and steel Research International 2020年第9期27卷 1064-1072页

作者： J.chen Y.Zhang J.J.Wang c.M.Liu s.X.Zhao Key Laboratory for Anisotropy and Texture of Materials Ministry of EducationNortheastern UniversityShenyang 110819LiaoningChina shenyang Industrial Transformation Upgrading Promotion center Shenyang 110083LiaoningChina The state Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819LiaoningChina school of Materials science and Engineering Northeastern UniversityShenyang 110819LiaoningChina central Research Institute Baoshan Iron&Steel Co.Ltd.Shanghai 201999China

The deformation mechanisms and the flow stress behavior of a medium-manganese high-carbon steel during cold deformation at a strain rate of 10×5 s^-1 were explored using a universal testing machine,an X-ray diffractometer,a field emission scanning electron microscope and a high-resolution transmission electron *** results show that continuous step-up serrated flow behavior appears after the yielding point,and the true stress-strain curve is roughly divided into five stages based on distinctive densities and amplitudes of *** strengthening mechanisms of the experimental steel involve cottrell atmosphere,twinning-induced plasticity(TWIP)efect and transformation-induced plasticity(TRIP)*** effect is the dominant deformation mechanism,and deformation twins formed by TWIP effect comprise primary,secondary and ***,TRIP effect arises in the local high-strain *** element plays a key role in the transformation of the deformation mechanism.A small amount of carbide precipitates around twin boundaries lead to the formation of local carbon-poor regions,and Md temperature and stacking fault energy of medium-manganese high-carbon steel are propitious to the occurrence of TRIP *** addition,the contributions of various deformation mechanisms to plasticity are calculated,and that of TWIP effect is the greatest.

关键词： serrated flow Deformation mechanism Deformation twin Twinning-induced plasticity Transformation-induced plasticity

Dose rate effects on shape memory epoxy resin during 1 Me V electron irradiation in air

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Journal of Materials science & Technology 2021年第8期67卷 61-69页

作者： Longyan Hou Yiyong wu Debin shan Bin Guo Yingying Zong state Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China National Key Laboratory of Materials Behavior and Evaluation Technology in space Environments Harbin Institute of TechnologyHarbin 150001China

The effects of 1 Me V electron irradiation in air at a fixed accumulated dose and dose rates of 393.8,196.9,78.8,and 39.4 Gy s^(-1)on a shape memory epoxy(sMEP)resin were *** low-dose-rate irradiation,accelerated degradation of the shape memory performance was observed;specifically,the shape recovery ratio decreased exponentially with increasing irradiation time(that is,with decreasing dose rate).In addition,the glass transition temperature of the sMEP,as measured by dynamic mechanical analysis,decreased overall with decreasing dose *** dose rate effects of 1 Me V electron irradiation on the sMEP were confirmed by structural analysis using electron paramagnetic resonance(EPR)spectroscopy and Fourier transform infrared(FTIR)*** EPR spectra showed that the concentration of free radicals increased exponentially with increasing irradiation ***,the FTIR spectra showed higher intensities of the peaks at 1660 and 1720 cm^(-1),which are attributed to stretching vibrations of amide c=O and ketone/acid c=O,at lower dose *** intensities of the IR peaks at 1660 and 1720 cm^(-1) increased exponentially with increasing irradiation time,and the relative intensity of the IR peak at 2926 cm^(-1)decreased exponentially with increasing irradiation *** solid-state13 c nuclear magnetic resonance(NMR)spectra of the sMEP before and after 1 Me V electron irradiation at a dose of 1970 k Gy and a dose rate of 78.8 Gy s^(-1) indicated damage to the cH_(2)–N groups and aliphatic isopropanol *** result is consistent with the detection of nitrogenous free radicals,a phenoxy-type free radical,and several types of pyrolytic carbon radicals by *** the subsequent propagation process,the free radicals produced at lower dose rates were more likely to react with oxygen,which was present at higher concentrations,and form the more destructive peroxy free radicals and oxidation products such as acids,amides,and *** increase in peroxy

关键词： shape memory epoxy resin shape memory effect Electron irradiation Dose rate effect Free radical chain scission

shock Wave spectrum Forming around the compound Five-Hole Probe and its Influence on Pneumatic Parameters Acquisition during subsonic to supersonic Flow

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Journal of Thermal science 2024年第6期33卷 2019-2031页

作者： KAN Xiaoxu sUO Licheng LEI Haodong wu Wanyang ZHONG Jingjun Merchant Marine college Shanghai Maritime UniversityShanghai 201306China

supersonic wind tunnel experiment is one of the important measurements for developing advanced gas turbines,and supersonic multi-hole probes are sophisticated tools to measure pneumatic parameters in such ***,shock waves form around the probe head in supersonic flow,which affect the accuracy of *** this study,a supersonic five-hole probe is selected as the research ***,a compound five-hole pressure-temperature probe was designed and produced with 3D-printing ***,the shock wave spectrum was numerically calculated by three methods,which were the Mach number,density gradient,and shock function;in contrast to the other two methods,the shock function could accurately identify the types and ranges of shock and expansion *** results show that a strong shock wave is formed at the front section of the probe head,and the shock wave generated around the pressure measuring tube affects the total pressure and Mach number of the flow field,which causes the increase of *** intensity of the shock wave at the head of the pressure measuring tube is the largest,causing a decrease in the total pressure around the flow ***,to reduce the calculation errors caused by neglecting the compressibility of gases and the entropy increase,a gas compression factor δ_(s) was *** is proved that the error of the calculated pneumatic parameters is less than 5% and 10% in subsonic and supersonic condition,respectively,with the gas compression factor *** research results of this paper provide theoretical reference for the design and use of pneumatic probes during subsonic to supersonic flow.

关键词： pneumatic probes supersonic flow shock wave pneumatic parameter numerical simulation

cryptic species composition and genetic diversity within Bemisia tabaci complex in soybean in India revealed by mtcOI DNA sequence

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Journal of Integrative Agriculture 2015年第9期14卷 1786-1795页

作者： Prasanna H c Kanakala s Archana K Jyothsna P Varma R K Malathi V G Division of Vegetable Improvement Indian Institute of Vegetable Research Advanced centre for Plant Virology Division of Plant PathologyIndian Agricultural Research Institute Department of Plant Pathology Jawaharlal Nehru Krishi Vishwavidyalaya

Bemisia tabaci is a cryptic species complex, causing signiifcant loss on many agricultural y important crops worldwide. Knowledge on species composition and diversity within B. tabaci complex is critical for evolving sustainable pest management strategies. Here we investigate the whitelfy species complex in soybean in major soybean growing states of India. The mitochondrial cytochrome oxidase gene subunit-1 (mtcOI) based phylogenetic relationships established using Bayesian methods indicated the existence of three cryptic species namely Asia I, Asia II 1, and Asia II 7. Al the haplotypes detected in the study could be assigned to these three cryptic species fol owing the species demarcation criteria of 3.5%divergence threshold. Of these, Asia II 1 was found to be predominant with wide spread distribution across the surveyed regions from cool temperate zones to hot and humid tropical plains. On the contrary, cryptic species Asia II 7 showed localized distribu-tion. The Asia II 1 exhibited the highest haplotype diversity and Asia I showed high level of nucleotide diversity. There was a signiifcantly high genetic differentiation among these three cryptic species. The MEAM 1, a dreadful invasive species was not detected in the specimens tested in the current study. The diversity and distribution of three cryptic species is discussed in the light of current knowledge on distribution of whitelfy species in India and yel ow mosaic disease observed during sampling survey.

关键词： whitefly mitochondrial cytochrome oxidase gene subunit-1 AsiaⅠ AsiaⅡ 1 AsiaⅡ 7 begomovirus and yellow mosaic disease

Dielectric loss enhancement induced by the microstructure of coFe_(2)O_(4) foam to realize broadband electromagnetic wave absorption

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International Journal of Minerals,Metallurgy and Materials 2023年第7期30卷 1388-1397页

作者： Bin shi Hongsheng Liang Zijun Xie Qing chang Hongjing wu college of chemistry and chemical Engineering Shaanxi Key Laboratory of Chemical Reaction EngineeringYan’an UniversityYan’an 716000China MOE Key Laboratory of Material Physics and chemistry Under Extraordinary School of Physical Science and TechnologyNorthwestern Polytechnical UniversityXi’an 710072China

coFe_(2)O_(4)has been widely used for electromagnetic wave absorption owing to its high snoek limit,high anisotropy,and suitable saturation magnetization;however,its inherent shortcomings,including low dielectric loss,high density,and magnetic agglomeration,limit its application as an ideal *** study investigated a microstructure regulation strategy to mitigate the inherent disadvantages of pristine coFe_(2)O_(4)synthesized via a sol–gel auto-combustion method.A series of coFe_(2)O_(4)foams(s0.5,s1.0,and s1.5,corresponding to foams with citric acid(cA)-to-Fe(NO_(3))_(3)·9H_(2)O molar ratios of 0.5,1.0,and 1.5,respectively)with two-dimensional(2D)curved surfaces were obtained through the adjustment of cA-to-Fe^(3+)ratio,and the electromagnetic parameters were adjusted through morphology *** to the appropriate impedance matching and conductance loss provided by moderate complex permittivity,the effective absorption bandwidth(EAB)of s0.5 was as high as 7.3 GHz,exceeding those of most coFe_(2)O_(4)-based ***,the EAB of s1.5 reached 5.0 GHz(8.9–13.9 GHz),covering most of the X band,owing to the intense polarization provided by lattice defects and the heterogeneous *** three-dimensional(3D)foam structure circumvented the high density and magnetic agglomeration issues of coFe_(2)O_(4)nanoparticles,and the good conductivity of 2D curved surfaces could effectively elevate the complex permittivity to ameliorate the dielectric loss of pure coFe_(2)O_(4).This study provides a novel idea for the theoretical design and practical production of lightweight and broadband pure ferrites.

关键词： coFe_(2)O_(4)foam lightweight broadband absorption microstructure regulation dielectric loss