Advanced Materials Research Vols. 287-290

Abstract: The different types of nanometer crystal manganese dioxides was prepared by hydrothermal method, and was characterized by scanning electron microscopy and X-ray diffraction. Meanwhile, the catalytic properties of the samples were investigated in catalytic degradation of methylene blue. The results showed that the different types of nano-crystal manganese dioxide had uniform crastallinity and good dispersion. And the degradation rate of methylene blue has reached more than 60%.

Abstract: The scientific progress has improved human life quality, meanwhile today's high-stress lifestyle has resulted in a rising demand for health care and well-being products. The high technology products and innovation make our life more convenient and at the same time the negative effects, such as electrostatic and electromagnetic wave. High electromagnetic wave affects the human body in different ways. Technological innovation and product aesthetics are both important for modern life quality. Companies have invested in research, development and essential household items to improve the lives such as thermal retentivity and antistatic. In this study, PET fiber was used as warp, and PET fiber, bamboo charcoal nylon fiber and stainless steel fiber employed as weft to weave three groups of resilient warp knitted fabrics. Then various examination have been conducted, including electromagnetic shielding effectiveness, tensile strength test, tearing strength test, burst strength test. The results indicate that the electromagnetic shielding effectiveness of bamboo charcoal / stainless steel resilient warp knitted fabrics attained 35 dB and the shielding achieved 99.9 %. The tensile strength of bamboo charcoal / stainless steel resilient warp knitted fabrics (weft) reached 26 MPa.

Abstract: In order to increase the designing precision and study the main factors influencing the stability of metal elastic-jumping membrane, a set of experimental equipments have been designed to test the stability of metal elastic-jumping membrane. The laws of influencing the stability of elastic-jumping membrane were studies by changing the thickness, high, radius etc structure parameter. It shows that the increasing of high and thickness can enhance the distortion rigidity of metal elastic-jumping membrane, result in the increase of critical load at losing stability; the increasing of diameter can reduce the distortion rigidity of metal elastic-jumping membrane, result in the decrease of critical load at losing stability. At the same time, the correctness of finite element model was confirmed, and the basis was established for finite element method applying in optimizing design of metal elastic-jumping membrane.

Abstract: The electronic properties of organic field effect transistors limit the efficiency of integrated circuits build on basis of printed organic semiconductors. In order to control the mobility of high efficient semiconductors, like rubrene, tetracene, tetracyanoquinodimethane (TCNQ), copper phthalocyanine and many others, single-crystal field-effect transistors have been prepared on surfaces of single crystals and characteristics have been measured. The highest mobility has been measured on rubrene single crystals. The mobility of as-grown crystals measured by air-gap field effect transistor is in the range of 10 cm²/Vs but falls below 1 cm²/Vs during reduction. It was observed that the measured mobility depends on the dielectric used for field effect transistors.

Abstract: In production of manufactured fine aggregate (MFA) from magnetite mill tailings (MT), the micro fines (particles smaller than 75 microns) was strictly eliminated. This results in lower utilization of the resources and worse micro grading of MFA. The mortar samples were prepared with MT at various micro fines contents to investigate the effects on their fluidities and strengths. In optimal water-to-powder ratio (w/p, all powders included), the fluidities of mortars reached maximum and the strengths of mortars could be improved at suitable content of micro fines in MFA. The application proves that MT can be used as MFA to prepare construction mortars up to standard and micro fines can be substituted for mineral admixture to prepare composite mortars for improving workability. So more MT can be utilized and micro fines in the tailings can take effect.

Abstract: Forming progress of hydration productions CH are analyzed in this paper by ways of SEMs of hardened cement paste with or without ground granulated blast furnace slag and high-calcium fly ash. It presents that minerals with latently hydraulic or pozzolanic are apt to absorb CH crystal to grow around it. There are clearly hydraulic reactions in the partial surface of mineral grains connecting with CH crystal and there is little hydration in the part without CH surrounding. It indicates that increasing the absorbability of mineral grain for CH crystal is probably a useful method to advance reactivity of minerals with low activity.

Abstract: The corrosion behavior of reinforcing steel bar HPB235 in concrete structure in 0.5% NaCl solution was investigated and its mechanical properties were tested before and after corrosion. The results showed that, with corrosion time increasing from 240h to 720h, the corrosion rate increases and the corrosion becomes heavier and heavier, but the corrosion scale is not changed obviously in compositions. After 720h, the yield strength is decreased by less than 5%, but the tensile strength and the elongation are decreased by more than 10%.

Abstract: Four kinds of fiber reinforced asphalt mixture formula are made, i.e., non fiber, polyester fiber, polyacrylonitrile fiber and the compound of the last two fibers, and then the Residual Marshall Stability (RMS) tests and Residual Cleavage Strength (RCS) tests are carried out. It is found that with the adding of fiber, the RMS is raised from 88% to 92% and the RCS from 86% to 88%. In the view of water-relating stability enhancement, the compound fiber is the best, the polyacrylonitrile fiber is the second, and the polyester fiber is at last, however, it is still better than plain asphalt mixture. More compaction work should be done on fiber reinforced asphalt mixture in practical engineering.

Abstract: In order to research the expansive deformation performance of shrinkage-compensating steel fiber reinforced shotcrete, orthogonal test was done in this paper with expansive agent content and steel fiber content as variable. And the test results showed that restrictive expansion ratio was gradually increased when curing in water, while reducing in air. The difference between restrictive expansion ratio and free expansion ratio used to make self stress by stretching steel bar and steel fiber. Meanwhile the maximum self stress is 0.58MPa, and the minimum self stress is 0.23 MPa in concrete. What’s more, both the maximum self stress and the minimum self stress could meet the requirements for self stress of shrinkage-compensating concrete.

Abstract: The effect of anhydrite on the hydration of CFBC ash-clinker-water system was investigated by ettringite content, chemically combined water content and X-ray diffraction. The results show that the effect of anhydrite on ettringite content at earlier age is significantly greater than that at later age. This work confirms that anhydrite plays a significant role in promoting the hydration of CFBC ash-clinker-water system.