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Recently, the studies on the application of coral sand in concrete construction attracted wide attention, especially in China. Coral sand and coral sand powder (CSP) can be used as fine aggregate and mineral admixture in concrete, respectively. The main component of CSP is calcium carbonate (CaCO3), up to 96%. However, the utilization of CSP in cement mortar will cause performance degradation. Ground-Granulated Blast Furnace Slag (BFS) be used to improve the property of CSP-Portland cement mortar. In this study, the coral sand powder-blast furnace slag-Portland cement (CSP-BFS-PC) ternary system had been used to produce cement paste and mortar. The hydration product of the CSP-BFS-PC ternary system are researched fundamentally by X-ray diffraction, and compressive strength are tested at different curing age. The results show that CSP can suppress consumption of C3A. 15wt.% BFS can offset the strength loss of cement mortar due to the substitution of CSP for cement (CSP less than 15wt.%), especially 7-28 days.

Portland cement is widely used in civil engineering. However, Portland cement-based materials are easy to be corroded by seawater in marine environment. Many research show the corrosion resistance of Portland cement mortar can be improved by add appropriate amount of mineral admixture.Sulphoaluminate cement have high strength and good corrosion seawater resistance. However, the short setting time and high hydration heat of sulphoaluminate cement limit its application in civil engineering.Portland cement-sulphoaluminate cement (PC-CSA) not only have high strength and corrosion resistance but also long setting time.In this work, the sulphoaluminate cement was used to partially replace Portland cement. The replacement level of sulphoaluminate cement was 10 %, 20 % and 30 % by weight of Portland cement. Mortar specimens was soaked in sodium chloride solution under standard curing after 28 days. The concentration of sodium chloride solution was 3.5wt %. Mechanical properties , corrosion resistance and setting time of PC-CSA binary system were tested in the research. The hydration behavior of binary system was determined by isothermal calorimetry and X-ray diffraction methods. Microstructure of the binary system at different ages were analyzed by scanning electron microscope. The strength of PC-CSA binary system was tested at different curing ages up to 28 days.The results show when replacement level of sulphoaluminate cement is 20%, the comprehensive strength up to 50MPa and higher than other groups at 28 days soaked in corrosion solution.when replacement level of sulphoaluminate cement is 20%,the corrosion resistance is best,and penetration depth of chloride ions is the least.

Portland cement is widely used in civil engineering. However, Portland cement-based materials are easy to be corroded by seawater in marine environment. Many research show the corrosion resistance of Portland cement mortar can be improved by add appropriate amount of mineral admixture.Sulphoaluminate cement have high strength and good corrosion seawater resistance. However, the short setting time and high hydration heat of sulphoaluminate cement limit its application in civil engineering.Portland cement-sulphoaluminate cement (PC-CSA) not only have high strength and corrosion resistance but also long setting time.In this work, the sulphoaluminate cement was used to partially replace Portland cement. The replacement level of sulphoaluminate cement was 10 %, 20 % and 30 % by weight of Portland cement. Mortar specimens was soaked in sodium chloride solution under standard curing after 28 days. The concentration of sodium chloride solution was 3.5wt %. Mechanical properties , corrosion resistance and setting time of PC-CSA binary system were tested in the research. The hydration behavior of binary system was determined by isothermal calorimetry and X-ray diffraction methods. Microstructure of the binary system at different ages were analyzed by scanning electron microscope. The strength of PC-CSA binary system was tested at different curing ages up to 28 days.The results show when replacement level of sulphoaluminate cement is 20%, the comprehensive strength up to 50MPa and higher than other groups at 28 days soaked in corrosion solution.when replacement level of sulphoaluminate cement is 20%,the corrosion resistance is best,and penetration depth of chloride ions is the least.

Recently, the studies on the application of coral sand in concrete construction attracted wide attention, especially in China. Coral sand and coral sand powder (CSP) can be used as fine aggregate and mineral admixture in concrete, respectively. The main component of CSP is calcium carbonate (CaCO3), up to 96%. However, the utilization of CSP in cement mortar will cause performance degradation. Ground-Granulated Blast Furnace Slag (BFS) be used to improve the property of CSP-Portland cement mortar. In this study, the coral sand powder-blast furnace slag-Portland cement (CSP-BFS-PC) ternary system had been used to produce cement paste and mortar. The hydration product of the CSP-BFS-PC ternary system are researched fundamentally by X-ray diffraction, and compressive strength are tested at different curing age. The results show that CSP can suppress consumption of C3A. 15wt.% BFS can offset the strength loss of cement mortar due to the substitution of CSP for cement (CSP less than 15wt.%), especially 7-28 days.

As one of the mineral admixtures, silica fume (SF) with high pozzolanic reactivity is generally used to improve the properties of concrete. Most commercial silica fume used in concrete project is dry densified silica fume (DSF). It consists of a good deal of agglomerates of sizes ranging from 10 μm to several millimeters. The size of the undispersed silica fume is usually larger than that of the cement particle. At present, the effect of DSF on the hydration of cement is lack of studied. In this study, the commercial dry DSF is sifted into three sections (>150 μm, 80 ~ 150 μm, 35 ~ 80 μm) by different sieves. The amount of densified silica fume in mixture is 5% by weight of total binder. The used water/binder ratio (w/b) is 0.5. The effect of the fineness of DSF on the setting time of cement paste is firstly discussed. The hydration process of cement incorporated with different fineness of SF is investigated by a semi-adiabatic calorimetric for 3 days at 20 °C and x-ray diffraction (XRD). The obtained results indicate that the setting time of cement paste increases with the decrease of the fineness of DSF. At the w/b ratio of 0.5, the addition of SF has little effect on the hydration period of cement paste. But the hydration rate of cement is decreased with the increase of the size of DSF particles.

Due to the nature of high stability and eco-friendliness, layered n-type Bi2O2Se-based thermoelectric materials have attracted extensive research interest. In order to reduce lattice thermal conductivity and enhance thermoelectric performance of Bi2O2Se-based thermoelectric materials, here, we introduced Te substitution at O site into Bi2O2-2xTe2xSe prepared by a shear exfoliation method. The induced high-density nanosized Bi2O2Se grains and point defects can effectively scatter both mid and short-wavelength phonons, leading to a low lattice thermal conductivity of ~0.57 W m−1 K−1 at ~773 K. Furthermore, Se vacancies generated by the shear exfoliation induced a high carrier concentration approaching the optimized level, and in turn lead to relatively high electrical performance. The synergistic high electrical performance and low lattice thermal conductivity secured a record-high dimensionless figure of merit, zT, of ~0.69 at ~773 K. This study indicates that shear exfoliation method and Te substitution are promising methods to optimize the thermoelectric properties of Bi2O2Se-based thermoelectric materials.

According to recent studies, gas sensors based on MoSe2 have better detection performance than graphene-based sensors, especially for N-based gas molecules, but the reason for that is not fully understood at the microscopic level. Here, we investigate the adsorption of CO, CO2, NH3, NO and NO2 gas molecules on MoSe2 monolayer by the density functional theory calculations. Our results reveal that indeed MoSe2 monolayer is more sensitive to adsorption of N-containing gas molecules than C-containing, which can be attributed to the distinct charge transfer between the gas molecules and MoSe2. The conductance was further calculated using the nonequilibrium Green's function (NEGF) formalism. The reduced conductance was found for NH3 and NO2 adsorbed MoSe2, consistent with the high sensitivity of MoSe2 for NH3 and NO2 molecules in the recent experiments. In addition, the adsorption sensitivity can significantly be improved by an external electric field, which implies the controllable gas detection by MoSe2. The magnetic moments of adsorbed NO and NO2 molecules can also be effectively modulated by the field-sensitive charge transfer. Our results not only give microscopic explanations to the recent experiments, but also suggest using MoSe2 as a promising material for controlled gas sensing.

In this paper, a MnFe2O4-Cellulose magnetic composite aerogel (MnCA) with high adsorption capacity was fabricated by in situ incorporating MnFe2O4 to regenerated cellulose hydrogel matrix, followed by CO2 supercritical drying. A green synthetic strategy was performed by using renewable cellulose materials, environmentally benign cellulose solvents and facile synthetic conditions. The results showed that the obtained magnetic cellulose aerogel had a continuous and tiered three dimensional network with interconnected fibrils of about 30 nm in width, which was similar to those of cellulose aerogel prepared from NaOH/urea solution via CO2 supercritical drying. Meanwhile, they had high specific surface areas of 236-288 m(2)/g and total pore volume of 0.55-0.88 cm(3)/g. In addition, the hybrid aerogel showed superparamagnetism with maximum saturation magnetization reaching up to 18.53 emu/g. The magnetic nanocomposite aerogel could be used for biological and environmental applications. The adsorption test showed that MnCA had rapid adsorption rate and excellent adsorption ability of removing heavy metal ions in aqueous solution which could attain to 63.3 mg/g within 100 min. Moreover, all the composite aerogels exhibited good reusability and could be easily reused from the water after adsorption.

beta-dicalcium silicate (beta-Ca2SiO4 or beta-C2S in cement chemistry notation) is one of the most important minerals in cement. An improvement of its hydration rate would be the key point for developing environmentally-friendly cements with lower energy consumption and CO2 emissions. However, there is a lack of fundamental understanding on the water/beta-C2S surface interactions. In this work, we aim to evaluate the water adsorption on three beta-C2S surfaces at the atomic scale using density functional theory (DFT) calculations. Our results indicate that thermodynamically favorable water adsorption takes place in several surface sites with a broad range of adsorption energies (-0.78 to -1.48 eV) depending on the particular mineral surface and adsorption site. To clarify the key factor governing the adsorption of the electronic properties of water at the surface were analyzed. The partial density of states (DOS), charge analysis, and electron density difference analyses suggest a dual interaction of water with a beta-C2S (100) surface including a nucleophilic interaction of the water oxygen lone pair with surface calcium atoms and an electrophilic interaction (hydrogen bond) of one water hydrogen with surface oxygen atoms. Despite the elucidation of the adsorption mechanism, no correlation was found between the electronic structure and the adsorption energies.

During the hydration of cement, tricalcium aluminate (C3A) reacts with gypsum and forms ettringite (AFt). Once all gypsum is consumed, ettringite can further react with remaining C3A and form monosulfate (AFm) at 1–2 days. Normally, at early ages, ettringite all transfers to AFm phase. After several months or years, ettringite can form again if a new source of sulfate becomes available in the pore solution of the paste, viz. delayed ettringite formation. In previous study, it was found that delayed ettringite forms in Portland cement concrete when the concrete samples were cured under moist conditions, i.e., without external sulfate phase. This delayed ettringite formation may result in the decrease of resistance of Portland cement concrete to chloride penetration. After that, it was found that ettringite, viz. delayed ettringite formation, also generated in fly ash concrete. The formation of ettringite, however, has no obvious influence on the resistance of fly ash concrete to chloride penetration.

At present, there is an increasing interest on the use of calcium sulphoaluminate (C4A3$) in cement. In this paper, pure mineral of sulphoaluminate (C4A3$) was prepared in laboratory. Different dosages of steel slag and C4A3$ were blended into cement. The aim of this paper is to investigate the compressive strength of this ternary system. The test results show that the addition of C4A3$ can improve the strength of cement. Larger C4A3$ dosage (7%) may reduce the 28 days strength. The optimal C4A3$ dosage is 5%. In ternary system, C4A3$ has no obvious improvement, while 5% dosage could improve the strength a little.

At present, there is an increasing interest on the use of calcium sulphoaluminate (C4A3$) in cement. In this paper, pure mineral of sulphoaluminate (C4A3$) was prepared in laboratory. Different dosages of steel slag and C4A3$ were blended into cement. The aim of this paper is to investigate the compressive strength of this ternary system. The test results show that the addition of C4A3$ can improve the strength of cement. Larger C4A3$ dosage (7%) may reduce the 28 days strength. The optimal C4A3$ dosage is 5%. In ternary system, C4A3$ has no obvious improvement, while 5% dosage could improve the strength a little.

During the hydration of cement, tricalcium aluminate (C3A) reacts with gypsum and forms ettringite (AFt). Once all gypsum is consumed, ettringite can further react with remaining C3A and form monosulfate (AFm) at 1–2 days. Normally, at early ages, ettringite all transfers to AFm phase. After several months or years, ettringite can form again if a new source of sulfate becomes available in the pore solution of the paste, viz. delayed ettringite formation. In previous study, it was found that delayed ettringite forms in Portland cement concrete when the concrete samples were cured under moist conditions, i.e., without external sulfate phase. This delayed ettringite formation may result in the decrease of resistance of Portland cement concrete to chloride penetration. After that, it was found that ettringite, viz. delayed ettringite formation, also generated in fly ash concrete. The formation of ettringite, however, has no obvious influence on the resistance of fly ash concrete to chloride penetration.

A combination of derivatization, reversed-phase high performance liquid chromatography (RP-HPLC), and mass spectrometry techniques has been explored for the characterization of small sugars, medium-size oligosaccharide , and glycans detached from chicken egg albumin (ovalbumin) by hydrazinolysis. The PMP derivatization method was preferred over pyridylamination owing to the simplicity of the reaction involved and, most importantly, its better enhancement of ionization efficiency in fast atom bombardment (FAB), electrospray (ESI), and matrix-assisted laser desorption/ionization (MALDI-MS). For oligosaccharides with more than three rings, only PMP-derivatives produced structurally related information, and only ESI and MALDI were utilized while FAB was dropped. Sensitivity studies were carried out using a standard oligosaccharide, tetraglucose. The other aim was to study the fragmentation patterns of PMP-derivatives. Qualitative fragmentation studies of PMP-derivatives were also carried out with typical N-linked oligosaccharides obtained commercially. PMP-derivatives of these standard oligosaccharides not only produce abundant molecular ions, but also informative sequence-related fragment ions in ESI-MS and ESI-MS/MS while the MALDI mass spectra mainly yielded molecular ions, such as (M + H) $\sp+,$ and (M + NA) $\sp+.$ With this information in hand, the derivatization method was then applied to N-glycans cleaved from ovalbumin, which has only one N-glycosylation site. (Abstract shortened by UMI.)

Deuterium nuclear magnetic resonance (NMR) spectroscopy was used to explore molecular motions in the mesophases of calamatic liquid crystals 4-' n'-pentyloxybenzylidene-4'-heptylaniline (50.7), ' '-(methoxybenzylidine)-'p'-n-butylaniline(MBBA or 10.4), 4-'n'-hexyloxy-4'-cyanobiphenyl (60CB), a mixture of 60CB and 4-'n'-octyloxy-4'-cyanobiphenyl (80CB), and discotic liquid crystals hexakis('n'-hexyloxy)triphenylene(HAT6). The Zeeman and quadrupolar spin--lattice relaxation times were measured as a function of temperature at 15.1 MHz and 46 MHz using a broadband multiple--pulse sequence. In addition, quadrupolar splittings were measured for 60CB, 60CB/80CB mixture and columnar phase of HAT6. The TZ model was used to interpret the deuteron relaxation of biaxial molecules in the uniaxial medium. For 50.7, the analysis of the relaxation data in the nematic and smectic A phases supports a model which includes director fluctuations and rotational diffusion of an asymmetric rigid rotor in a biaxial potential of mean torque. The molecular biaxiality of the molecule is found, based on the relaxation data, to give a small positive molecular biaxial order parameter 'S'' xx'-'Syy'. In addition, the activation energy for the tumbling motion of the molecule is found to be larger than that for the spinning motion. For MBBA, the zero-frequency spectral densities ' J'0(0) data is quantitatively interpreted using a model that includes director fluctuations and rotational diffusion of symmetric rotors in a nematic phase. The contribution to 'J'0(0) from director fluctuations has mainly a second-order component, whereas the first-order contribution to 'J'1([omega]) is suppressed in the megahertz region (Larmor frequencies are 15.1 and 46 MHz) due to the high-frequency cutoff, which is estimated to be around 3-10 MHz for MBBA. For 60CB and 60CB/80CB mixture, the data analyses were carried out for both samples in order to achieve a consistent physical picture. The additive potential metho

A combination of derivatization, reversed-phase high performance liquid chromatography (RP-HPLC), and mass spectrometry techniques has been explored for the characterization of small sugars, medium-size oligosaccharide , and glycans detached from chicken egg albumin (ovalbumin) by hydrazinolysis. The PMP derivatization method was preferred over pyridylamination owing to the simplicity of the reaction involved and, most importantly, its better enhancement of ionization efficiency in fast atom bombardment (FAB), electrospray (ESI), and matrix-assisted laser desorption/ionization (MALDI-MS). For oligosaccharides with more than three rings, only PMP-derivatives produced structurally related information, and only ESI and MALDI were utilized while FAB was dropped. Sensitivity studies were carried out using a standard oligosaccharide, tetraglucose. The other aim was to study the fragmentation patterns of PMP-derivatives. Qualitative fragmentation studies of PMP-derivatives were also carried out with typical N-linked oligosaccharides obtained commercially. PMP-derivatives of these standard oligosaccharides not only produce abundant molecular ions, but also informative sequence-related fragment ions in ESI-MS and ESI-MS/MS while the MALDI mass spectra mainly yielded molecular ions, such as (M + H) $\sp+,$ and (M + NA) $\sp+.$ With this information in hand, the derivatization method was then applied to N-glycans cleaved from ovalbumin, which has only one N-glycosylation site. (Abstract shortened by UMI.)

Deuterium nuclear magnetic resonance (NMR) spectroscopy was used to explore molecular motions in the mesophases of calamatic liquid crystals 4-' n'-pentyloxybenzylidene-4'-heptylaniline (50.7), ' '-(methoxybenzylidine)-'p'-n-butylaniline(MBBA or 10.4), 4-'n'-hexyloxy-4'-cyanobiphenyl (60CB), a mixture of 60CB and 4-'n'-octyloxy-4'-cyanobiphenyl (80CB), and discotic liquid crystals hexakis('n'-hexyloxy)triphenylene(HAT6). The Zeeman and quadrupolar spin--lattice relaxation times were measured as a function of temperature at 15.1 MHz and 46 MHz using a broadband multiple--pulse sequence. In addition, quadrupolar splittings were measured for 60CB, 60CB/80CB mixture and columnar phase of HAT6. The TZ model was used to interpret the deuteron relaxation of biaxial molecules in the uniaxial medium. For 50.7, the analysis of the relaxation data in the nematic and smectic A phases supports a model which includes director fluctuations and rotational diffusion of an asymmetric rigid rotor in a biaxial potential of mean torque. The molecular biaxiality of the molecule is found, based on the relaxation data, to give a small positive molecular biaxial order parameter 'S'' xx'-'Syy'. In addition, the activation energy for the tumbling motion of the molecule is found to be larger than that for the spinning motion. For MBBA, the zero-frequency spectral densities ' J'0(0) data is quantitatively interpreted using a model that includes director fluctuations and rotational diffusion of symmetric rotors in a nematic phase. The contribution to 'J'0(0) from director fluctuations has mainly a second-order component, whereas the first-order contribution to 'J'1([omega]) is suppressed in the megahertz region (Larmor frequencies are 15.1 and 46 MHz) due to the high-frequency cutoff, which is estimated to be around 3-10 MHz for MBBA. For 60CB and 60CB/80CB mixture, the data analyses were carried out for both samples in order to achieve a consistent physical picture. The additive potential metho