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Experimental study and field application of calcium sulfoaluminate cement for rapid repair of concrete

Yanhua GUAN, Ying GAO, Renjuan SUN, Moon C. WON, Zhi GE

《结构与土木工程前沿（英文）》 2017年 第11卷 第3期   页码 338-345 doi: 10.1007/s11709-017-0411-0

摘要： The fast-track repair of deteriorated concrete pavement requires materials that can be placed, cured, and opened to the traffic in a short period. Type III cement and Calcium Sulfoaluminate (CSA) cement are the most commonly used fast-setting hydraulic cement (FSHC). In this study, the properties of Type III and CSA cement concrete, including compressive strength, coefficient of thermal expansion (CTE) and shrinkage were evaluated. The test results indicate that compressive strength of FSHC concrete increased rapidly at the early age. CSA cement concrete had higher early-age and long term strength. The shrinkage of CSA cement concrete was lower than that of Type III cement concrete. Both CSA and Type III cement concrete had similar CTE values. Based on the laboratory results, the CSA cement was selected as the partial-depth rapid repair material for a distressed continuously reinforced concrete pavement. The data collected during and after the repair show that the CSA cement concrete had good short-term and long-term performances and, therefore, was suitable for the rapid repair of concrete pavement.

关键词： Calcium Sulfoaluminate (CSA) cement     Type III cement     coefficient of thermal expansion (CTE)     shrinkage     rapid repair    

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掺梳形减水剂水泥浆体早期水化产物形貌研究

蒋亚清

《中国工程科学》 2011年 第13卷 第9期   页码 69-75

摘要：

为揭示梳形减水剂对水泥早期水化的影响规律，指导工程应用,通过SEM分析，研究了掺用3种典型结构的梳形减水剂的水泥浆体早期水化产物形貌及其电子特征数据。结果表明，梳形减水剂加速了水泥早期水化反应，且丙烯酸类、马来酸类共聚物分别促进了AFt、AFm的形成。因此，梳形减水剂品种对水泥早期水化和混凝土工程性能具有较大影响，应根据使用要求合理选用，必要时与缓凝剂、引气剂或消泡剂复合使用。

关键词： 梳形减水剂     水泥水化     钙矾石     微观形貌    

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Effect of embedment length of untreated natural fibres on the bond behaviour in cement mortar

Gudimella RAMAKRISHNA, Sriraman PRIYADHARSHINI

《结构与土木工程前沿（英文）》 2018年 第12卷 第4期   页码 454-460 doi: 10.1007/s11709-017-0454-2

摘要： The present investigation is focused on studying the effects of various matrices with 1:3, 1:4 and 1:5 mortars and fibre types of sisal and coir on the bond behavior at various ages of curing, i.e., 24 h, 3 d, 7 d and 28 d. The other parameters included in the investigation are water/cement (w/c) ratio, sand gradation and embedment length of fibres. In addition, the type of failure of sisal and coir fibres for different mixes of mortars at various curing ages is also reported. From the results, it is seen that the bond strength is improving with respect to age of curing in case of sisal fibres, but decreases in case of coir fibres. The failure of fibres due to fibre fracture is observed in sisal fibres and fibre pullout is observed in coir fibres. The other varying parameters such as mortar mixes, sand gradation, w/c ratio and embedded length also showed significant effect on bond behaviour of sisal and coir fibre with the cement mortar mixes.

关键词： bond strength     cement mortar     natural fibre     pullout test     type of failure    

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Approaching the commercial threshold of solar water splitting toward hydrogen by III-nitrides nanowires

《能源前沿（英文）》 doi: 10.1007/s11708-023-0870-z

摘要： Approaching the commercial threshold of solar water splitting toward hydrogen by III-nitrides nanowires

关键词： threshold solar water     splitting hydrogen III    

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Self-assembled bright luminescent hierarchical materials from a tripodal benzoate antenna and heptadentate Eu(III) and Tb(III) cyclen complexes

Aramballi J. Savyasachi, David F. Caffrey, Kevin Byrne, Gerard Tobin, Bruno D'Agostino, Wolfgang Schmitt, Thorfinnur Gunnlaugsson

《化学科学与工程前沿（英文）》 2019年 第13卷 第1期   页码 171-184 doi: 10.1007/s11705-018-1762-3

摘要：

The europium heptadentate coordinatively unsaturated (Eu(III)) and the terbium (Tb(III)) 1,4,7,10-tetraazacyclododecane (cyclen) complexes 1 and 2 were used in conjunction with ligand 3 (1,3,5-benzene-trisethynylbenzoate) to form the supramolecular self-assembly structures 4 and 5; this being investigated in both the solid and the solution state. The resulting self-assemblies gave rise to metal centered emission (both in the solid and solution) upon excitation of 3, confirming its role as a sensitizing antenna. Drop-cased examples of ligand 3, and the solid forms of 4 and 5, formed from both organic and mixture of organic-aqueous solutions, were analyzed using Scanning Electron Microscopy, which showed significant changes in morphology; the ligand giving rise to one dimensional structures, while both 4 and 5 formed amorphous materials that were highly dense solid networks containing nanoporous features. The surface area (216 and 119 m2·g−1 for 4 and 5 respectively) and the ability of these porous materials to capture and store gases such as N2 investigated at 77 K. The self-assembly formation was also investigated in diluted solution by monitoring the various photophysical properties of 3–5. This demonstrated that the most stable structures were that consisting of a single antennae 3 and three complexes of 1 or 2 (e.g., 4 and 5) in solution. By monitoring the excited state lifetimes of the Eu(III) and Tb(III) ions in H2O and D2O respectively, we showed that their hydration states (the q-value) changed from ~2 to 0, upon formation of the assemblies, indicating that the three benzoates of 3 coordinated directly to the each of the three lanthanide centers. Finally we demonstrate that this hierarchically porous materials can be used for the sensing of organic solvents as the emission is highly depended on the solvent environment; the lanthanide emission being quenched in the presence of acetonitrile and THF, but greatly enhanced in the presence of methanol.

关键词： self-assembly     supramolecular chemistry     lanthanides     Eu(III) and Tb(III) complexes     luminescence     metallostars    

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Extending blending proportions of ordinary Portland cement and calcium sulfoaluminate cement blends:

《结构与土木工程前沿（英文）》 2021年 第15卷 第5期   页码 1249-1260 doi: 10.1007/s11709-021-0770-4

摘要： This study extended blending proportion range of ordinary Portland cement (OPC) and calcium sulfoaluminate (CSA) cement blends, and investigated effects of proportions on setting time, workability, and strength development of OPC-CSA blend-based mixtures. Thermogravimetric analysis (TGA) and X-ray diffraction (XRD) were conducted to help understand the performance of OPC-CSA blend-based mixtures. The setting time of the OPC-CSA blends was extended, and the workability was improved with increase of OPC content. Although the early-age strength decreased with increase of OPC content, the strength development was still very fast when the OPC content was lower than 60% due to the rapid formation and accumulation of ettringite. At 2 h, the OPC-CSA blend-based mortars with OPC contents of 0%, 20%, 40%, and 60% achieved the unconfined compressive strength (UCS) of 17.5, 13.9, 9.6, and 5.0 MPa, respectively. The OPC content had a negligible influence on long-term strength. At 90 d, the average UCS of the OPC-CSA blend-based mortars was 39.2 ± 1.7 MPa.

关键词： calcium sulfoaluminate cement     cement blends     hydration reaction     setting     workability     compressive strength    

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ITZ microstructure, thickness, porosity and its relation with compressive and flexural strength of cementmortar; influence of cement fineness and water/cement ratio

《结构与土木工程前沿（英文）》 2022年 第16卷 第2期   页码 191-201 doi: 10.1007/s11709-021-0792-y

摘要： A new insight into the interfacial transition zone (ITZ) in cement mortar specimens (CMSs) that is influenced by cement fineness is reported. The importance of cement fineness in ITZ characterizations such as morphology and thickness is elucidated by backscattered electron images and by consequences to the compressive (Fc) and flexural strength (Ff), and porosity at various water/cement ratios. The findings indicate that by increasing the cement fineness the calcium silicate hydrate formation in the ITZ is favored and that this can refine the pore structures and create a denser and more homogeneous microstructure. By increasing cement fineness by about 25% of, the ITZ thickness of CMSs was reduced by about 30% and Fc was increased by 7%–52% and Ff by 19%–40%. These findings illustrate that the influence of ITZ features on the mechanical strength of CMSs is mostly related to the cement fineness and ITZ microstructure.

关键词： cement fineness     interfacial transition zone     compressive and flexural strength    

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III族氮化物材料和设备的未来技术及用途

Shuji Nakamura

《工程（英文）》 2015年 第1卷 第2期   页码 161-161 doi: 10.15302/J-ENG-2015059

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Removal of Cu(II) and Fe(III) from aqueous solutions by dead sulfate reducing bacteria

Hong’en QUAN, He BAI, Yang HAN, Yong KANG, Jiao SUN

《化学科学与工程前沿（英文）》 2013年 第7卷 第2期   页码 177-184 doi: 10.1007/s11705-013-1324-7

摘要： The biosorption properties of dead sulfate reducing bacteria (SRB) for the removal of Cu(II) and Fe(III) from aqueous solutions was studied. The effects of the biosorbent concentration, the initial pH value and the temperature on the biosorption of Cu(II) and Fe(III) by the SRB were investigated. FTIR analysis verified that the hydroxyl, carbonyl and amine functional groups of the SRB biosorbent were involved in the biosorption process. For both Cu(II) and Fe(III), an increase in the SRB biosorbent concentration resulted in an increase in the removal percentage but a decrease in the amount of specific metal biosorption. The maximum specific metal biosorption was 93.25 mg?g at pH 4.5 for Cu(II) and 88.29 mg?g at pH 3.5 for Fe(III). The temperature did not have a significant effect on biosorption. In a binary metal system, the specific biosorption capacity for the target metal decreased when another metal ion was added. For both the single metal and binary metal systems, the biosorption of Cu(II) and Fe(III) onto a SRB biosorbent was better represented by a Langmuir model than by a Freundlich model.

关键词： sulfate reducing bacteria     biosorption     Cu(II)     Fe(III)    

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Study of bond strength between various grade of Ordinary Portland Cement (OPC) and Portland PozzolaneCement (PPC) mixes and different diameter of TMT bars by using pullout test

A D POFALE, S P WANJARI

《结构与土木工程前沿（英文）》 2013年 第7卷 第1期   页码 39-45 doi: 10.1007/s11709-013-0193-y

摘要： Since last two decades, the Portland Pozzolane Cement (PPC) is extensively used in structural concrete. But, till to date, a few literature is available on bond strength of concrete using PPC mixes. There are many literatures available on bond strength of concrete mixes using Ordinary Portland Cement (OPC). Hence, a comparative study was conducted on bond strength between OPC and PPC mixes. In the present investigation, total 24 samples consisting of M20, M35 and M50 grades of concrete and 16 and 25 mm diameter of TMT bar were tested for 7 and 28 days. The pullout bond test was conducted on each specimen as per IS: 2770-1967/1997 [1] and the results were observed at 0.25 mm slip at loaded end called as critical bond stress and at maximum bond load called as maximum bond stress. It was observed that the critical bond strength of PPC mixes is 10% higher than OPC mixes. Whereas, marginal improvement was noticed in maximum bond strength of PPC mixes. Hence, based on these findings, it could be concluded that development length for PPC mixes could be reduced by 10% as compared with same grade of OPC mixes.

关键词： bond strength     Portland Pozzolane Cement (PPC) concrete     Ordinary Portland Cement (OPC) concrete     bond between concrete and steel     pullout test     development length    

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Group III metabotropic glutamate receptors and drug addiction

null

《医学前沿（英文）》 2013年 第7卷 第4期   页码 445-451 doi: 10.1007/s11684-013-0291-1

摘要：

Neuroadaptations of glutamatergic transmission in the limbic reward circuitry are linked to persistent drug addiction. Accumulating data have demonstrated roles of ionotropic glutamate receptors and group I and II metabotropic glutamate receptors (mGluRs) in this event. Emerging evidence also identifies Gαi/o-coupled group III mGluRs (mGluR4/7/8 subtypes enriched in the limbic system) as direct substrates of drugs of abuse and active regulators of drug action. Auto- and heteroreceptors of mGluR4/7/8 reside predominantly on nerve terminals of glutamatergic corticostriatal and GABAergic striatopallidal pathways, respectively. These presynaptic receptors regulate basal and/or phasic release of respective transmitters to maintain basal ganglia homeostasis. In response to operant administration of common addictive drugs, such as psychostimulants (cocaine and amphetamine), alcohol and opiates, limbic group III mGluRs undergo drastic adaptations to contribute to the enduring remodeling of excitatory synapses and to usually suppress drug seeking behavior. As a result, a loss-of-function mutation (knockout) of individual group III receptor subtypes often promotes drug seeking. This review summarizes the data from recent studies on three group III receptor subtypes (mGluR4/7/8) expressed in the basal ganglia and analyzes their roles in the regulation of dopamine and glutamate signaling in the striatum and their participation in the addictive properties of three major classes of drugs (psychostimulants, alcohol, and opiates).

关键词： group III metabotropic glutamate receptors     cocaine     amphetamine     alcohol     opiate    

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Preparation of manganese (III) acetylacetonate nanoparticles via an environmentally benign route

M. S. Shalaby, H. Abdallah

《化学科学与工程前沿（英文）》 2013年 第7卷 第3期   页码 329-337 doi: 10.1007/s11705-013-1339-0

摘要： With the hope of overcoming the generation of hazardous materials to human health and environment, serious and great endeavor have been made in catalyst fabrication using green chemistry technology. In this paper, the manganese (III) acetylacetonate nanoparticles with diameters of about 146 nm were prepared by a simple and environmentally benign route based on hydrolysis of KMnO followed by reaction with acetylacetone in rapid stirring rate or ultrasonication. The as-prepared samples were characterized by X-ray diffraction, energy dispersive X-ray fluorescence (EDIX), Fourier transfer infrared spectroscopy and scanning electron microscope. Various parameters were investigated, and the pure and stable crystals of manganese (III) acetylacetonate could be obtained in 98% conversion at a molar ratio 7∶1 of acetylacetone to KMnO and 75°C after 60 min. We further proposed a mathematical model, and the predicted results from model were in good agreement with experimental results.

关键词： green chemistry     manganese (III) acetylacetonate     reaction conversion     Mathematical model    

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Autogenous healing mechanism of cement-based materials

《结构与土木工程前沿（英文）》   页码 948-963 doi: 10.1007/s11709-023-0960-3

摘要： Autogenous self-healing is the innate and fundamental repair capability of cement-based materials for healing cracks. Many researchers have investigated factors that influence autogenous healing. However, systematic research on the autogenous healing mechanism of cement-based materials is lacking. The healing process mainly involves a chemical process, including further hydration of unhydrated cement and carbonation of calcium oxide and calcium hydroxide. Hence, the autogenous healing process is influenced by the material constituents of the cement composite and the ambient environment. In this study, different factors influencing the healing process of cement-based materials were investigated. Scanning electron microscopy and optical microscopy were used to examine the autogenous healing mechanism, and the maximum healing capacity was assessed. Furthermore, detailed theoretical analysis and quantitative detection of autogenous healing were conducted. This study provides a valuable reference for developing an improved healing technique for cement-based composites.

关键词： autogenous healing     cement-based materials     healing mechanism     aggregation effect    

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Exposure-response of Cr(III)-organic complexes to Saccharomyces cerevisiae

Nivedita CHATTERJEE, Zejiao LUO,

《环境科学与工程前沿（英文）》 2010年 第4卷 第2期   页码 196-202 doi: 10.1007/s11783-010-0008-5

摘要： Hexavalent chromium [Cr(VI)] bioreduction produces soluble Cr(III)-organic complexes. The Cr(III)-organic complexes are relatively stable once they are formed, and no data about their toxicity were reported. Therefore, this study aims to investigate the bioavailability and toxicity of the soluble Cr(III)-organic complexes. L-1 wild type yeast strain was chosen as the model organism and Cr(III)-citrate was selected as the representative compound of the Cr(III)-organic complexes. The short-term chronic aquatic toxicity tests of the Cr(III)-citrate was explored by measuring growth inhibition, direct viable cell count, dry biomass, biosorption, and the amount of CO production. Cr(III)-citrate exerted a toxicity of 51mg/L with an , which was calculated from the percent growth inhibition. These toxicity data would be helpful to define the toxic potential of the organo-chromium-III compounds in the environment.

关键词： Cr(III)-organic complexes     Saccharomyces cerevisiae     toxicity     EC50     bioavailability    

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Research review of the cement sand and gravel (CSG) dam

Xin CAI, Yingli WU, Xingwen GUO, Yu MING

《结构与土木工程前沿（英文）》 2012年 第6卷 第1期   页码 19-24 doi: 10.1007/s11709-012-0145-y

摘要： The cement sand and gravel (CSG) dam is a new style of dam that owes the advantages both of the concrete faced rock-fill dam (CRFD) and roller compacted concrete (RCC) gravity dam, because of which it has attracted much attention of experts home and abroad. At present, some researches on physic-mechanical property of CSG material and work behavior of CSG dam have been done. This paper introduces the development and characteristics of CSG dam systematically, and summarizes the progress of the study on basic tests, constitutive relation of CSG material and numerical analysis of CSG dam, in addition, indicates research and application aspect of the dam.

关键词： cement sand and gravel (CSG) dam     cement sand and gravel (CSG) material     research review    

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标题 作者 时间 类型 操作

Experimental study and field application of calcium sulfoaluminate cement for rapid repair of concrete

Yanhua GUAN, Ying GAO, Renjuan SUN, Moon C. WON, Zhi GE

期刊论文

掺梳形减水剂水泥浆体早期水化产物形貌研究

蒋亚清

期刊论文

Effect of embedment length of untreated natural fibres on the bond behaviour in cement mortar

Gudimella RAMAKRISHNA, Sriraman PRIYADHARSHINI

期刊论文

Approaching the commercial threshold of solar water splitting toward hydrogen by III-nitrides nanowires

期刊论文

Self-assembled bright luminescent hierarchical materials from a tripodal benzoate antenna and heptadentate Eu(III) and Tb(III) cyclen complexes

Aramballi J. Savyasachi, David F. Caffrey, Kevin Byrne, Gerard Tobin, Bruno D'Agostino, Wolfgang Schmitt, Thorfinnur Gunnlaugsson

期刊论文

Extending blending proportions of ordinary Portland cement and calcium sulfoaluminate cement blends:

期刊论文

ITZ microstructure, thickness, porosity and its relation with compressive and flexural strength of cementmortar; influence of cement fineness and water/cement ratio

期刊论文

III族氮化物材料和设备的未来技术及用途

Shuji Nakamura

期刊论文

Removal of Cu(II) and Fe(III) from aqueous solutions by dead sulfate reducing bacteria

Hong’en QUAN, He BAI, Yang HAN, Yong KANG, Jiao SUN

期刊论文

Study of bond strength between various grade of Ordinary Portland Cement (OPC) and Portland PozzolaneCement (PPC) mixes and different diameter of TMT bars by using pullout test

A D POFALE, S P WANJARI

期刊论文

Group III metabotropic glutamate receptors and drug addiction

null

期刊论文

Preparation of manganese (III) acetylacetonate nanoparticles via an environmentally benign route

M. S. Shalaby, H. Abdallah

期刊论文

Autogenous healing mechanism of cement-based materials

期刊论文

Exposure-response of Cr(III)-organic complexes to Saccharomyces cerevisiae

Nivedita CHATTERJEE, Zejiao LUO,

期刊论文

Research review of the cement sand and gravel (CSG) dam

Xin CAI, Yingli WU, Xingwen GUO, Yu MING

期刊论文