Sinoma International Engineering Co.

Beijing, China

Sinoma International Engineering Co.

Beijing, China
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Zhou J.,Sinoma International Engineering Co. | Qian S.,Nanjing Southeast University | Ye G.,Technical University of Delft | Ye G.,Ghent University | And 3 more authors.
Cement and Concrete Composites | Year: 2012

Engineered cementitious composites (ECC) is a class of ultra ductile fiber reinforced cementitious composites, characterized by high ductility and tight crack width control. The polyvinyl alcohol (PVA) fiber with a diameter of 39 μm and a length of 6-12 mm is often used. Unlike plain concrete and normal fiber reinforced concrete, ECC shows a strain-hardening behavior under tensile load. Apart from the mix design, the fiber distribution is another crucial factor for the mechanical properties of ECC, especially the ductility. In order to obtain a good fiber distribution, the plastic viscosity of the ECC mortar before adding fibers needs to be controlled, for example, by adjusting water-to-powder ratio or chemical admixtures. However, such adjustments have some limitations and may result in poor mechanical properties of ECC. This research explores an innovative approach to improve the fiber distribution by adjusting the mixing sequence. With the standard mixing sequence, fibers are added after all solid and liquid materials are mixed. The undesirable plastic viscosity before the fiber addition may cause poor fiber distribution and results in poor hardened properties. With the adjusted mixing sequence, the mix of solid materials with the liquid material is divided into two steps and the addition of fibers is between the two steps. In this paper, the influence of different water mixing sequences is investigated by comparing the experimental results of the uniaxial tensile test and the fiber distribution analysis. Compared with the standard mixing sequence, the adjusted mixing sequence increases the tensile strain capacity and ultimate tensile strength of ECC and improves the fiber distribution. This concept is further applied in the development of ECC with high volume of sand. © 2011 Elsevier Ltd. All rights reserved.


Zhang Q.,Tianjin University | Yang X.,Tianjin University | Liu T.,Tianjin University | Liu Y.,Tianjin University | Yan H.,SINOMA International Engineering Co.
Chinese Journal of Sensors and Actuators | Year: 2013

A design of a smart digital visual sensor for inline visual inspection system for the white body of cars is reported. Based on ARM 6410 processor, the system integrates the functionalities of data collection, 2D pixel-level locating, communication as well as controlling, and it aims at solving the problem of poor signal processing capability and bad immunity to interference in traditional visual sensors. A fast and stable pixel-level template matching algorithm based on Linux system is designed, which uses NNPROD as similarity measurement and adopts a multi-resolution strategy. In the matching algorithm, a new 2D summation method called "Running Sum with Complementing Lost Pixels" is proposed, which optimizes the calculation of the cross-correlation coefficient. With a comprehensive fault-tolerant mechanism in addition to the matching algorithm, the visual sensor has been proved experimentally to run the pixel-level locating function with high speed, high precision and high robustness, and to fulfill the task of front-end data collecting and processing in the inspection system.


Zhong S.,Tongji University | Li J.,Tongji University | Li J.,Sinoma International Engineering Co. | Ni K.,Tongji University | And 2 more authors.
Construction and Building Materials | Year: 2013

In order to understand why polymer-modified mortars (PMMs) with hydroxypropylmethyl cellulose (HPMC) often show better properties than that without HPMC, the influence of HPMC on the adsorption of styrene-acrylic ester (SAE) latex particles on cement grains was studied through the particle size distribution and the zeta potential of latex modified cement paste (LMCP) with and without HPMC keep the latex/cement ratio (L/C) to 10%. The differences between the calculated and measured particle size distribution curves of LMCP indicate strong interactions between latex particles and cement grains in fresh cement pastes. The particle size distribution results show that the adsorbed rate of SAE on cement is 75.24% in LMCP, while the adsorbed rate of SAE latex particles in LMCP with HPMC is 4% lower than that in LMCP without HPMC. The zeta potential results show that the zeta potential of LMCP is negative, the equilibrium zeta potential of LMCP with HPMC is more negative than that of LMCP without HPMC and decreases with the increase of the HPMC to cement ratio (HPMC/C). The microstructures of hardened LMCP with and without HPMC were observed using scanning electronic microscopy (SEM). Without etching of LMCP with or without HPMC, the polymer films are more easily seen in pores while hard to found at the cement matrix. After etching the specimen in diluted hydrochloric acid (HCl), coherent polymer films were observed. The differences of the polymer films in samples prepared with different procedures, that is the specimens stored in absolute alcohol or not, show that they are composite films of SAE latex and HPMC in LMCP with HPMC. Higher the HPMC/C is, bigger the covered area of the polymer films is on the surface of pores, and more rigid the polymer films are, what can be confirmed from the tensile test results of films made from the HPMC and SAE latex mixture that show decreased elongation at break and increased tensile strength with the increase of HPMC to latex ratio (HPMC/L). © 2012 Elsevier Ltd. All rights reserved.


Zhong S.,Tongji University | Han D.,Tongji University | Li J.,Sinoma International Engineering Co.
Advanced Materials Research | Year: 2013

Whether and how many polymer particles will be adsorbed on the cement grain in the polymer-modified cement composites (PCC) is still a question. In this paper the possibility and the test method of adsorption of polymer particles on the cement grain were reviewed. A theoretical analysis on the principle of adsorption was discussed. It was then summarized that polymer particles will be adsorbed by the cement mainly due to electrostatic attract and the entropy effect. The zeta potential measurement based on the electroacoustic principle is a useful tool to study the adsorption of polymer, in combination with sedimentation of the polymer latex-modified cement with high water/cement (W/C) ratio quantitative evaluation of the adsorption is possible. © (2013) Trans Tech Publications, Switzerland.


Zhong S.-Y.,Tongji University | Li J.-M.,Tongji University | Li J.-M.,Sinoma International Engineering Co. | Han D.-D.,Tongji University | And 2 more authors.
Jianzhu Cailiao Xuebao/Journal of Building Materials | Year: 2013

Because of less thorough study on the properties of cement pastes with superplasticizers and latex mixed together, the influence of different mixing procedures of superplasticizers and latex on the ζ potential of cement pastes(fresh) were analyzed using the ZetaProbe instrument. The experimental results show that with adding different use level(by mass) of polycarboxylic superplasticizer(PC), the cement pastes with both PC and latex added have negative or positive ζ potential. However, the ζ potential of cement pastes with both naphthalene formaldehyde condensate superplasticizer(NF) and latex added is lower than that of cement pastes with NF added but higher than that of cement pastes with latex added. Adding NF into cement pastes with latex added, the absolute value of equilibrium ζ potential of the cement pastes is lower than that of cement pastes with NF added, cement pastes with latex added and cement pastes with both NF and latex added. Adding PC into cement pastes with latex added, the ζ potential of the cement pastes can even reach the equilibrium ζ potential of cement paste with latex added. When latex is added in, the ζ potential of cement paste with 1.0% PC added doesn't change, but the ζ potential of cement paste with 0.1% PC added decreases greatly to a certain value. The ζ potential of cement paste with NF added increases from -10 mV to -6 mV when latex is added in, and then increases slowly with the increase of use level of latex. By adding superplasticizer(NF or PC) and latex into cement pastes simultaneously or adding latex into cement pastes with superplasticizer(NF or PC) added, the adsorbed proportion of polymer particles on cement grains can be decreased.


Zhong S.-Y.,Tongji University | Li J.-M.,Tongji University | Li J.-M.,Sinoma International Engineering Co. | Han D.-D.,Tongji University | And 2 more authors.
Jianzhu Cailiao Xuebao/Journal of Building Materials | Year: 2012

The influence of viscosity modifying admixtures (VMA) and superplasticizers and mixing of these two agents on zeta (ζ) potential of cement pastes (fresh) were analyzed using the ZetaProbe instrument. The experimental results show that since cement grains adsorb VMA or superplasticizer molecules, the ζ potential of cement pastes with VMA or superplasticizer decreases. The ζ potential of cement pastes with both VMA and polycarboxylic superplasticizer (PC) shows that cement grains primarily adsorb PC molecules, whereas the absolute value of ζ potential of cement pastes with both VMA and naphthalene formaldehyde condensate superplasticizer (NF) is lower than that with only NF. To add PC into cement pastes with VMA or to add VMA into cement pastes with PC will result in the ζ potential increase. The ζ potential of cement pastes with NF increases from -8 mV to -3 mV as VMA is added in. However, it is still lower than that with both VMA and NF. The ζ potential of cement pastes with VMA decreases as NF is added in, and the ζ potential absolute value is higher than that with both VMA and NF when the use level of NF increases to a certain value.


Zhang L.,Nanjing University of Technology | Lu J.-J.,Sinoma International Engineering Co. | Liu J.-Q.,Nanjing University of Technology | Li Y.,Nanjing University of Technology | And 2 more authors.
Chinese Journal of Inorganic Chemistry | Year: 2012

Series of (Sr 1-xEu x) 2CaMoO 6 orange-red phosphors were prepared by EDTA-citric acid complexing method. The crystal structure, doping site, morphology, and photoluminescent properties under different Eu 3+ concentrations were investigated by XRD, Raman spectra, SEM and fluorescence spectra. The results by Rietveld method indicate that the structure of Eu 3+ doped samples is orthorhombic double-perovskite with space group P2 1/n and slightly tilting octahedron of (Ca/Mo)O 6. With increasing Eu 3+ concentration, their lattice volumes decrease monotonously. Raman active mode T 2g, (1) is shifted to blue side resulting from the substitution of Sr 2+ in interstitial site among octahedrons by Eu 3+ ions. Under the excitation of broad and strong charge transfer band in near-UV range and blue light, the phosphor could emit a dominant orange light and a dominant red light, respectively. The (Sr 0.98Eu 0.02) 2CaMoO 6 phosphor has the strongest orange-red emission and this phosphor is a potential light conversion red material for N-UV LED chip.


Zhang L.,Nanjing University of Technology | Lu Z.,Nanjing University of Technology | Han P.,Nanjing University of Technology | Lu J.,Sinoma International Engineering Co. | And 3 more authors.
Journal of the American Ceramic Society | Year: 2012

Two different Sr2SiO4:Dy3+ phosphors were successfully synthesized at 1000°C for 4 h using NH4Cl or SrCl2 as the flux, respectively. The luminescence intensity of Sr2SiO4:Dy3+ was enhanced 60 times by the addition of 5 wt% NH4Cl. The phase evolution and photoluminescence (PL) properties of the phosphors were investigated by the calculation of phase equilibrium and the analysis of TG/DSC, XRD, SEM, and PL. The role of NH 4Cl was proved to be attributed to the formation of SrCl2 at ~300°C. The flux NH4Cl or SrCl2 lowered the decomposition temperature of carbonate and promoted the preferential formation of α' phase in the solid-state reaction through accelerating the kinetics of the formation of Sr2SiO4 by enhancing diffusion with more liquid phase. © 2012 The American Ceramic Society.


Zhang L.,Nanjing University of Technology | Han P.,Nanjing University of Technology | Han Y.,Sinoma International Engineering Co. | Lu Z.,Nanjing University of Technology | And 3 more authors.
Journal of Alloys and Compounds | Year: 2013

Double perovskite (Sr0.98-mBamEu 0.02)2Ca(Mo1-nWn)O 6 phosphors were successfully synthesized by an improved citrate-EDTA complexing method. The structure evolution and the resulting luminescence variation were systematically investigated by X-ray diffraction with Rietveld structure refinement, Fourier transform infrared spectra, Raman spectra, diffuse reflection spectra and photoluminescence spectra. The increased crystal symmetry and increased lattice parameters were observed from (Sr 0.98-mBamEu0.02) 2CaMoO6 phosphors. These series of phosphors could be effectively excited by near ultraviolet light and emitted a dominant 594 nm (5D0-7F1). The hypersensitive 5D0-7F2 transition (615 nm) varied with the changed structure symmetry. The CIE chromaticity coordinates were tuned from (0.642, 0.348) to (0.601, 0.389). The luminescence intensity of W 6+ substituted powders was greatly enhanced by the blue shift of charge transition band of (Mo/W)O6 with stable emission color. The composition-optimized Sr2Ca(Mo0.5W0.5)O 6:Eu phosphor had the highest luminescence intensity and quantum yield comparing to the commercial red phosphors. © 2012 Elsevier B.V. All rights reserved.


Zhou J.,Sinoma International Engineering Co. | Ye G.,Technical University of Delft | Sui T.,Sinoma International Engineering Co.
Concrete Repair, Rehabilitation and Retrofitting III - Proceedings of the 3rd International Conference on Concrete Repair, Rehabilitation and Retrofitting, ICCRRR 2012 | Year: 2012

Engineered Cementitious Composite (ECC) has been proposed to be one of the most promising repair materials. When ECC is used as a repair material, ECC can accommodate larger deformation, induced by differential shrinkage or external load, while maintaining a high load capacity. Moreover, the tight crack width of ECC retards the penetration of aggressive agents and thus improves the durability of the repaired structures. This paper presents an investigation on the performance of ECC for concrete repairs subjected to differential shrinkage. The surface cracking in the repair materials and the interface delamination were experimentally studied. © 2012 Taylor & Francis Group.

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