Advanced Materials Research Vol. 664

Abstract: In this paper, based on 28-day cubic compressive strength f_cu and splitting strength f_ts of pervious concrete with different porosity, aggregate size and of cubic size, correlation analysis was conducted among these three factors and strength using the software of SPSS (Statistical Package for the Social Sciences), in which a logarithmic function was used to do linear regression fitting about the relationship among the three parameters and the strength and then a formula was proposed. The analysis result shows that there is a certain higher-order function relationship between the three influencing factors and the strength, and it is contribute to analysis the impact of three parameters on strength by using natural logarithm to linearize the relationship of parameters. Studies have shown that porosity is the main factor that affects both f_cu and f_ts, and side length of the cube has a significant influence on f_ts but has no significant linear correlation with f_cu. And f_ts may be more sensitive to cube size on linear correlation than f_cu.

Abstract: Cement-soil is a kind of hydraulic composite building materials which is made by a certain percentage of cement soil particles and water. In order to make a deep research of seepage deformation and the variation law of cement-soil, laboratory test methods were adopted, carrying on deformation tests of indoor penetration on dry density, cement content and age etc, the factors owning outstanding effect on the seepage deformation and failure of cement-soil. The results shows that the seepage deformation and failure appear to change in certain laws with dry density, cement content and age. The gradient of seepage deformation and failure can reach one thousand under the condition that cement percentage is 5%, compaction maximum dry density is standard, and the age is 7 days. And numerical value will be enhanced significantly with the increase of cement content, dry density and the prolong of age. The seepage deformation and failure of cement-soil is not ordinary piping effect or soil-flow failure, but the form of shearing failure. The conclusion has not only a positive exploration significance of the academic research of the seepage deformation and failure of cement-soil, but also a certain practical significance on the geotechnical construction applying cement soil as impermeability.

Abstract: We numerically investigate the imaging properties of the two dimensional square photonic crystal. It is found that the dependence of the image-to-interface distance on the object-to-interface distance is almost linear. We can manipulate the near field location of the image through the object-to-interface distance. When the object is located 1μm away from the interface, the image locates at the output interface which can be used to realize the near field optical display.

Abstract: To improve the wear propery of 00Cr13Ni4Mo hydro turbine blade stainless steel, TiN-based coating was fabricated on 00Cr13Ni4Mo stainless steel by laser cladding using mixed powders of Ni60 and TiN. The microstructure of the coating was characterized by XRD and SEM techniques. The wear behaviour of the coating was also investigated. The wear resistance of the coating was evaluated under dry sliding wear condition at room temperature. The results show that the coating mainly consists of Ni-based solid solution and TiN phases. The coating exhibits excellent wear resistance due to its high hardness of TiN phase. The main wear mechanisms of the coating and the 00Cr13Ni4Mo sample are different, the former is abrasive wear and the latter is adhesive wear.

Abstract: In pH 6.6 Na₂HPO₄-NaH₂PO₄ buffer solution and in the presence of NaCl, nanogolds were aggregated to form stable aggregated-nanogolds (ANG). The molecular probe of coomassie brilliant blue G-250 (CBBG) adsorbed on the surface of ANG to form CBBG -ANG conjugates that produce the strongest surface-enhanced resonance Raman scattering (SERRS) peak at 1171 cm^-1. Under the optimized conditions, the increased intensity ΔI was linear to CBBG concentration in the range of 0.29×10^-7 - 4.68×10^-7 mol/L, with the regression equation of ΔI = 0.86C - 17.1. A fast and sensitive method for trace CBBG was developed.

Abstract: In 0.1 mol/L HCl medium and the presence of 0.3% glycerin as stabilizer, selenium (Ⅳ) was reduced by thiourea to form selenium nanoparticles, which exhibited a strong resonance Rayleigh scattering (RRS) peak at 366 nm. The RRS peak intensity increased when selenium (Ⅳ) increased. The increased RRS intensity at 366 nm (ΔI_366nm) was proportional to the selenium (Ⅳ) concentration (C) from 1 to 32 μg/L, with a regression equation of ΔI_366nm = 222.99 C+74.69, and detection limit of 1.19 ng/L. This proposed method was applied to detect selenium in samples, with satisfactory results.

Abstract: Using PEG-10000 and sodium citrate as stabilizer, and NaBH₄ as reducer, a stable nanosilver (AgNPs) sol was prepared. In pH 6.6 phosphate buffer solution containing NaCl, the AgNPs were aggregated to large particles, which lead to resonance Rayleigh scattering (RRS) peak at 350 nm enhancement. Upon addition of cysteine, the peak decreased. The decreased value ΔI is linear to cysteine concentration in the range of 5.0×10^-8-6.0×10^-7 mol/L. Thus, a new RRS method was proposed for detection of cysteine.

Abstract: In pH 8.0-9.1 NH₄Cl-NH₃ buffer solutions, the CdTe dots in different size appear fluorescence peak at 632 nm-748 nm. Upon addition of ClO₂, the fluorescence peak quenched linearly. The quenching fluorescence intensity is linear to the ClO₂ concentration. Thus, a sensitive and simple fluorescence method was proposed for the determination of ClO₂ in water sample.

Abstract: Using PEG-10000 and sodium citrate as stabilizer, and NaBH4 as reducer, a stable nanosilvers (AgNPs) sol was prepared. In pH 6.6 phosphate buffer solution containing NaCl, the AgNPs were aggregated to large particles, which lead to resonance Rayleigh scattering (RRS) peak at 350 nm enhancement. Upon addition of cysteine, the peak decreased. The decreased value ΔI is linear to cysteine concentration in the range of 5-60×10^-8 mol/L. Thus, a new RRS method was proposed for detection of cysteine.

Abstract: The effect of different heat treatments on microstructure and mechanical property of 30Si2MnCrMoV steel weld specimen was studied in this paper．A stress relieving annealing on the specimen was carried out immediately after welding. And then two heat treatments were carried out on the specimen. Observation results showed that the original microstructure of 30Si2MnCrMoV welded joints was granular pearlite and the microstructure of weld bead was coarse martensite. Lots of tempered martensite exited in the weld specimen under quenching-tempering heat treatment, the carbide was coarse and the content of retained austenite was little. Under Quenching and Partitioning (Q&P) heat treatment, the content of retained austenite increased to 7% and a small number of coarse carbides existed. The determination of mechanical properties showed that, comparing with quenching-tempering process, the plasticity and toughness of weld specimen treated by Q&P was enhanced significantly, the percentage elongation increased 30%, the impact energy increased 25% ,the intensity reduced little and comprehensive mechanical property was excellent. The tensile fracture of 30Si2MnCrMoV steel under Q&P presented dimples. The retained austenite which exited along the lath boundaries of lath martensite was the main reason of the reduction of secondary cracks and the improvement of plasticity and toughness.