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Influence of curing conditions on the shrinkage behavior of three-dimensional printed concrete formwork

Frontiers of Structural and Civil Engineering 2024年第8期18卷 1225-1236页

作者： M.BEKAERT K.van TITTELBOOM g.de schutter Magnel-Vandepitte Laboratory for structural Engineering and Building Materials Department of Structural Engineering and Building MaterialsFaculty of Engineering and ArchitectureGhent UniversityGhent 60 B-9052Belgium

The use of three-dimensional(3D)printed concrete as formwork is becoming more widely applied within the ***,the technology is still not optimized and there are many reports of preliminary cracking during the curing of cast *** is believed to result from differential shrinkage between the printed and cast *** cracks(in the printed concrete or at the interface between the infill and printed concrete)form a preferential path for aggressive substances and can reduce the durability of the combined concrete *** ensure the desired service life of the structure,it is important that the differential shrinkage between cast and printed concrete is *** study investigated the effect of curing conditions on the differential shrinkage behavior of 3D and cast *** influence of prewetting of the dry-cured 3D printed formwork was also *** the experimental program,a vibrated and self-compacting concrete were used as cast *** 3D printed formwork was produced and combined with cast concrete to simulate a concrete *** formwork was cured for 1,7,or 28 d exposed to the air(relative humidity:60%or 95%)or submerged in *** length change of the combined elements was observed over 56 d after concrete casting and throughout the thickness of the *** show that increasing the curing period in dry conditions of the printed concrete leads to an expansion of the formwork on the first day after *** expansion leads to a non-uniform strain evolution throughout the curing period of the combined *** concrete formwork stored in wet conditions does not expand after the casting process but tends to show a decreasing linear deformation within the whole elements.

关键词： 3D concrete printing formwork shrinkage curing

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Application of silver nitrate colorimetric method to non-steady-state diffusion test

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Journal of Central South University 2012年第10期19卷 2983-2990页

作者：元强邓德华史才军 g.de schutter School of Civil Engineering and Architecture Central South University College of Civil Engineering Hunan University Magnel Laboratory for Concrete Research Department of Structural EngineeringTechnologiepark-Zwijnaarde 904Ghent UniversityGhent(Zwijnaarde)B-9052Belgium

NT build 443, or profile fitting method, is often used to measure the diffusion coefficient of chloride in concrete. However, this method is quite laborious and needs special equipment. Colorimetric method is a quick and simple method to measure the penetration depth of chloride by spraying 0.1 mol/L silver nitrate solution. The objective of this work is to study the possibility of the use of colorimetric method in the calculation of non-steady-state diffusion coefficient. Twelve concrete mixtures with different supplementary cementitious materials and water-to-cement ratios of 0.35, 0.48 and 0.6 were used for study. According to NT build 443, the concrete specimens were immersed in 165 g/L NaC1 （2.8 mol/L） solution for 42 d. Both water-soluble （convert to free chloride） chloride and acid-soluble chloride at different layers of specimens were measured. The results show that the mean value of free chloride concentration at the color change boundary Cd was 0.306 mol/L. The surface free chloride concentration cs was obtained by profile fitting method, which was 40% lower than the chloride concentration of exposure solution after an immersion period of 42 d. Chloride diffusion coefficients obtained by the colorimetric method was not well correlated with those obtained by profile fitting method.

关键词： colorimetric method silver nitrate colorimetric method chloride diffusion non-steady-state diffusion concrete chloride-induced corrosion

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Adhesion performance of alkali-activated material for 3-dimensional printing of tunnel linings at different temperatures

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Frontiers of Structural and Civil Engineering 2024年第1期18卷 66-79页

作者： Yaxin TAO Xiaodi DAI geert de schutter Kim Van TITTELBOOM department of Structural Engineering and Building Materials Ghent UniversityGhent 9052Belgium

Robotic-based technologies such as automated spraying or extrusion-based 3-dimensional(3D)concrete printing can be used to build tunnel linings,aiming at reducing labor and mitigating the associated safety issues,especially in the high-geothermal ***-based 3D concrete printing(3DCP)has additional advantages over automated sprayings,such as improved surface quality and no ***,the effect of different temperatures on the adhesion performance of 3D-printed materials for tunnel linings has not been *** study developed several alkali-activated slag mixtures with different activator modulus ratios to avoid the excessive use of Portland cement and enhance sustainability of 3D printable *** thermal responses of the mixtures at different temperatures of 20 and 40℃ were *** adhesion strength of the alkali-activated material was evaluated for both early and later ***,the structural evolution of the material exposed to different temperatures was *** was followed by microstructure *** indicate that elevated temperatures accelerate material reactions,resulting in improved early-age adhesion ***,higher temperatures contribute to the development of a denser microstructure and enhanced mechanical strength in the hardened stage,particularly in mixtures with higher silicate content.

关键词： alkali-activated material 3DCP tunnel lining high-geothermal environment adhesion

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Structural changes in the obese brain

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Neural Regeneration Research 2024年第12期19卷 2561-2562页

作者： Anna R.R.Da Conceicao Marcelo N.N.Vieira Fernanda g.de Felice D’Or Institute for Research and Education Rio de JaneiroBrazil Institute of Medical Biochemistry Leopoldo de Meis Federal University of Rio de JaneiroRio de JaneiroBrazil Centre for Neuroscience Studies Department of Biomedical and Molecular Sciences&Department of PsychiatryQueen’s UniversityKingstonONCanada

Obesity represents a major global health concern,with widespread growing prevalence and severe consequences for the quality of life and life expectancy of affected individuals and for the economic burden of healthcare systems(Prospective Studies Collaboration,2009).Obesity is a well-established risk factor for a variety of conditions including metabolic,vascula r,and heart diseases,and seve ral types of cancer(Prospective Studies Collaboration,2009).

关键词： diseases consequences prevalence

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The shear strength of the interface between artificial rock and printed concrete at super-early ages

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Frontiers of Structural and Civil Engineering 2024年第1期18卷 51-65页

作者： Yong Yuan Xiaoyun Wang Jiao-Long Zhang Yaxin Tao Kim Van Tittelboom Luc Taerwe geert de schutter College of Civil Engineering Tongji UniversityShanghai 200092China State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China Belgium-China Joint Laboratory for Industrialized Construction Tongji UniversityShanghai 200092China Magnel-Vandepitte Laboratory for Structural Engineering and Building Materials Ghent UniversityGhent 9052Belgium

3D concrete printing has the potential to replace shotcrete for construction of linings of tunnels in hard *** shear strength of the interface between rock and printed concrete is vital,especially at super-early ***,traditional methods for testing the shear strength of the interface,e.g.,the direct shear test,are time-consuming and result in a high variability for fast-hardening printed *** this paper,a new fast bond shear test is *** test can be completed in 1 min,with another 2 min for preparing the next *** influence of the matrix composition,the age of the printed matrices,and the interface roughness of the artificial rock substrate on the shear strength of the interface was experimentally *** tests were conducted at the age of the matrices at the 1st,the 4th,the 8th,the 16th,the 32nd,and the 64th min after its final setting.A dimensionless formula was established to calculate the shear strength,accounting for the age of the printed matrices,the interface roughness,and the shear failure *** was validated by comparing the calculated results and the experimental results of one group of samples.

关键词： rock tunnel printed concrete interface fast bond shear test shear strength

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Photoionisation detection of a single Er3+ ion with sub-100-ns time resolution

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National Science Review 2024年第4期11卷 38-45页

作者： Yangbo Zhang Wenda Fan Jiliang Yang Hao guan Qi Zhang Xi Qin Changkui Duan gabriele g.de Boo Brett C.Johnson Jeffrey C.Mc Callum Matthew J.Sellars Sven Rogge Chunming Yin Jiangfeng Du CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences University of Science and Technology of China CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei National Laboratory University of Science and Technology of China Centre of Excellence for Quantum Computation and Communication Technology School of Physics University of New South Wales Centre of Excellence for Quantum Computation and Communication Technology School of Engineering RMIT University Centre of Excellence for Quantum Computation and Communication Technology School of Physics University of Melbourne Centre of Excellence for Quantum Computation and Communication Technology Research School of Physics and Engineering Australian National University

Efficient detection of single optical centres in solids is essential for quantum information processing, sensing and single-photon generation *** this work,we use radio-frequency（RF） reflectometry to electrically detect the photoionisation induced by a single Er3+ion in *** high bandwidth and sensitivity of the RF reflectometry provide sub-100-ns time resolution for the photoionisation *** this technique,the optically excited state lifetime of a single Er3+ion in a Si nano-transistor is measured for the first time to be 0.49±0.04μ*** results demonstrate an efficient approach for detecting a charge state change induced by Er excitation and *** approach could be used for fast readout of other single optical centres in solids and is attractive for large-scale integrated optical quantum systems thanks to the multi-channel RF reflectometry demonstrated with frequency multiplexing techniques.

关键词： single optical centres erbium ions RF reflectometry photoionisation detection

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Analysis of the Role of Syntactic Complexity in Students’ Reading Comprehension: A Teacher’s Perspective

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Journal of Contemporary Educational Research 2024年第8期8卷 253-264页

作者： Ma.Leticia Jose C.Basilan Daniel Reds g.de Sagun depEd Batangas Province BatangasPhilippines Batangas State University BatangasPhilippines Rizal College of Taal Taal BatangasBatangasPhilippines

This study examines the role of the syntactic complexity of the text in the reading comprehension skills of *** the qualitative method of research,this paper used structured interview questions as the main data-gathering *** language teachers from Coral na Munti National High School were selected as the respondents of the *** of the study suggests that the syntactic complexity of the text affects the reading comprehension of the *** found it challenging to understand the message that the author conveyed if he or she used a large number of phrases and clauses in one ***,the complex sentence syntactic structure was deemed the most challenging for students to *** overcome said challenges in comprehending text,various reading intervention programs were utilized by *** interventions include focused or targeted instruction and the implementation of the Project dear,suggested by the department of *** programs were proven to help students improve their comprehension as well as their knowledge in syntactical structure of *** study underscores the importance of selecting appropriate reading materials and implementing suitable reading intervention programs to enhance students’comprehension skills.

关键词： Reading comprehension Syntactic complexity Reading intervention program Syntactic structure

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Interplay of RNA-binding proteins controls germ cell development in zebrafish

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Journal of genetics and genomics 2024年第9期51卷 889-899页

作者： de-Li Shi Laboratory of developmental Biology CNRS-UMR7622Institut de Biologie Paris-Seine(IBPS)Sorbonne University75005 ParisFrance

The specification of germ cells in zebrafish mostly relies on an inherited mechanism by which localized maternal determinants,called germ plasm,confer germline fate in the early *** studies have partially allowed the identification of key regulators governing germ plasm formation and subsequent germ cell ***-binding proteins,acting in concert with other germ plasm components,play essential roles in the organization of the germ plasm and the specification,migration,maintenance,and differentiation of primordial germ *** loss of their functions impairs germ cell formation and causes sterility or sexual *** is emerging that they instruct germline development through differential regulation of mRNA fates in somatic and germ ***,the challenge remains to decipher the complex interplay of maternal germ plasm components in germ plasm compartmentalization and germ cell *** failure to control the developmental outcome of germ cells disrupts the formation of gametes,it is important to gain a complete picture of regulatory mechanisms operating in the germ cell *** review sheds light on the contributions of RNA-binding proteins to germ cell development in zebrafish and highlights intriguing questions that remain open for future investigation.

关键词： germplasm Primordialgerm cell germlinestem cell gametogenesis Zebrafish RNA-binding protein Posttranscriptional gene expression Translational activation and repression

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Tweaking the acid-sensitivity of transiently thermoresponsive polyacrylamides with cyclic acetal repeating units

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Science China Chemistry 2020年第4期63卷 504-512页

作者： Simon Van Herck Bruno g.de geest department of Pharmaceutics Ghent UniversityGhentBelgium

Merging the characteristics of thermoresponsive and stimuli-degradable polymers yields so-called transiently thermoresponsive polymers, which can find application for the design of injectable gels, nanoparticles, etc. within a biomedical context. Among these polymers, only a limited number is reported which shows selective degradation under mild acidic conditions. However,extension of the library of transiently thermoresponsive polymers is desired to broadening the biomaterials toolbox to suit specific needs. Three monomers were developed by modification of 2-hydroxyethylacrylamide(HEAm) via tetrahydropyranylation or-furanylation with 3,4-dihydro-2 H-pyran(DHP), 2,3-dihydrofuran(DHF) or 2,3-dihydro-5-methylfuran(MeDHF). The presence of an acetal or ketal bond provided the monomers a pH-dependent hydrolysis behavior ranging from minutes to days. RAFT polymerisation allowed for the construction of homopolymers with temperature responsive behavior and pH-dependent hydrolysis which was strongly influenced by nature of the monomeric repeating units.

关键词： acetals polyacrylamides stimuli-responsive

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Stereotactic body radiotherapy in pancreatic adenocarcinoma

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Hepatobiliary & Pancreatic Diseases International 2024年第1期23卷 14-19页

作者： Carolina de la Pinta Radiation Oncology department Ramón y Cajal University HospitalIRYCISAlcaláUniversity28034 MadridSpain

Background:Stereotactic body radiotherapy(SBRT)in pancreatic cancer allows high delivery of radiation doses on tumors without affecting surrounding *** review aimed at the SBRT application in the treatment of pancreatic *** sources:We retrieved articles published in MEDLINE/PubMed from January 2017 to december *** used in the search included:“pancreatic adenocarcinoma”OR“pancreatic cancer”AND“stereotactic ablative radiotherapy(SABR)”OR“stereotactic body radiotherapy(SBRT)”OR“chemoradiotherapy(CRT)”.English language articles with information on technical characteristics,doses and fractionation,indications,recurrence patterns,local control and toxicities of SBRT in pancreatic tumors were *** articles were assessed for validity and relevant ***:Optimal doses and fractionation have not yet been ***,SBRT could be the standard treatment in patients with pancreatic adenocarcinoma in addition to ***,the combination of SBRT with chemotherapy may have additive or synergic effect on pancreatic ***:SBRT is an effective modality for patients with pancreatic cancer,supported by clinical practice guidelines as it has demonstrated good tolerance and good disease *** opens a possibility of improving outcomes for these patients,both in neoadjuvant treatment and with radical intent.

关键词： Chemoradiotherapy Pancreatic adenocarcinoma Radiotherapy Stereotactic body radiotherapy Stereotactic ablative radiotherapy

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