Advanced Materials Research Vol. 413

Abstract: The concrete under penetration has a restricted deform and is in intrinsic friction state. By used conservation of mass, conservation of momentum and velocity expression on wave front, the velocity field of the pulverized zone near penetration is obtained. The boundary conditions and the continuum conditions were also considered for the obtained velocity field. The pulverized concrete near the penetration is described by Mohr-Coulomb criterion. Based on the conclusions above, cavity expand theory and the expand equation of inconsistent deform, the resistance of projectile is gained in intrinsic friction state. In according to movement differential equation, the deceleration model is built which can describe different phases for penetration and perforation. The decelerations of different size projectiles with different velocity were calculated and were contrasted with experimental data.

Abstract: Based on nanosensor patents applied in Korea from 1962-2009, collected in Derwent Innovation Index database, this paper elaborates innovation status and development trends of nanosensor technology in Korea, through the quantitative analysis of patent distribution in the state, the year, the application, and the enterprise, in hope of providing an objective statistic reference for future policy directions and academic researches.

Abstract: A GaN epilayer with tri-layer AlGaN interlayer grown on Si (111) by metal-organic chemical vapor deposition (MOCVD) method was discussed by synchrotron radiation x-ray diffraction (SRXRD) and Rutherford backscattering (RBS)/C. The crystal quality of the epilayer is very good with a χ_min=2.1%. According to the results of the θ-2θ scan of GaN(0002) and GaN(1122), the epilayer elastic strains in perpendicular and parallel directions were calculated respectively to be-0.019% and 0.063%. By the angular scan using RBS/C around a symmetric [0001] axis and an asymmetric [1213] axis in the (1010) plane of the GaN layer, the tetragonal distortion (e_T ) were determined to be 0.09%. This result coincides with that from SRXRD perfectly. The strain decreases gradually towards the near-surface layer, which will avoid the film cracks efficiently and improve the crystal quality of the GaN epilayer remarkably.

Abstract: Effects of the magnetic field on confinement of the coaxial twined ECR plasmas were studied using the Lanmuir probe diagnostic technique. Under the magnetic-mirror confinement, the plasma density was quite high in the vicinity of the axis of the ECR sources but it decreased rapidly with increasing radial distance; while under the cusped field confinement, the density was lower but uniform. The trend was similar for the electron temperature and the plasma potential. This property may be utilized in materials processes to meet different requirements. Key words: Electron cyclotron resonance (ECR), Plasma, Magnetic confinement, The cusped field confinement. PACS: 52.80.Pi, 52.55.-s, 52.70.-m

Abstract: The effect of CO₂ on seal capacity of cement mantle causes casing corrosion and reduces the life of oil well. The corrosion proof of cement system is studied to improve the integrity and seal properties of the cement stone under acidic medium. The CO₂ corrosion test of 5 blocks cement under high temperature and high pressure was conducted. Compressive strength, permeability and corrosion depth were measured and morphology after corrosion was observed by scanning electron microscope. A density cement slurry formulations was selected by analyzing the experimental data. It not only has excellent corrosion resistance, but also has properties of anti-gas breakthrough, reduction of free water and stability. It can meet cementing requirement of different well depth conditions.

Abstract: Based on former experimental achievement in laboratory, application and construction of high performance concrete (HPC) in pavement of highway were introduced to the paper. The HPC was proportioned with compound admixtures of 12% fly ash and 12% perlite powder replacing cement in equal mass. Perlite powder of both is a new mineral admixture, originated natural volcanic rock perlite composed of mainly aluminosilicate glass, was ground to mostly under 45 μm so as to possess pozzolanic activity, and then added to concrete as a supplementary cementitious material to substitute for partial cement. Multiplex of the two admixtures is profitable to increase workability, mechanical properties and durability during post-stage for concrete in varying degrees. The testing slump and construction fit of the fresh concrete in situ were shown that both of admixtures improved workability of the concrete. HPC samples remained in field and drilled from pavement were determined and investigated on mechanical properties and durability by means of test. It has been observed by inspected result of that flexural strength of these concrete are above 5 MPa at 28 cured days and compression strength about 40 MPa. The indexes of their abrasion resistance distribute throughout 1.94—2.63 kilo-rotation/mm at 90 days. These measured mechanical characteristics are so large enough to the technical specification of heavy traffic grade highway on mechanical property. To investigate durability of the HPC, the charge passed and the chloride diffusion coefficient in concrete at 90 cured days obtained from the accelerated chloride migration test were determined with RCM experimental equipment. The values of charge passed in the concrete were lower and ranged in 449—928 Coulomb, which revealed that the HPC are also better permeability resistance of chloride ion and be able to sustain in environment of chloride salt for 100 years. The chloride diffusion coefficients of the HPC were scattered in 1.4—4.7×10^-12m²s^-1. These parameters exhibited completely the HPC better or excellent for electrical indication of concrete’s ability to resist chloride ion penetration referent to relevant standards and information.

Abstract: Insoluble starch xanthate (ISX) is made with the potato starch and can be used for the treatment of cadmium-containing waste water. The performance of treatment and the influence factors with ISX made in this experiment are studied in this paper. It is shown that the removal rate of cadmium ion in wastewater can reach over 96%, when pH value of reaction liquid is 8.0, the adsorption time is 0.5h, and the concentration of cadmium ions in waste water is 30 mg·L^-1.The adsorption mechanism was also discussed. It is shown that ISX promises to be a new treatment adsorbent to wastewater containing the low concentration cadmium. There are some merits with ISX: the smaller recruitment; better processing effect and so on. It is with chemical adsorption that wastewater containing cadmium is treated by insoluble starch xanthate.

Abstract: After activated carbon is oxidized and modified with nitric acid (1:1), its cation exchange capacity can amount to 1.840 mmol • g^-1. The modified activated carbon is used as adsorbent for the treatment of Cr (Ⅵ)-containing wastewater at room temperature, and its removal mechanism is discussed in this paper. It is shown that: when the pH value of the aqueous solution being 2.5-3.0;the adsorption time being 3.0h, the removal rate of Cr (Ⅵ) in the aqueous solution can reach 97% and its adsorption capacity can amount to 45.66 mg • g^-1. From the results, it can be also seen that the adsorption curve to chromium in wastewater by the modified activated carbon better meets the Freundlich isotherm, and ion exchange adsorption mainly does its work.

Abstract: In order to obtain the dynamic shearing property of high N alloy steel, the plugging test was performed by using the improved Hopkinson pressure bar system. As dynamic shearing strengths, the dynamic shearing energies during plugging process of two type high N alloy steels were determined from the shearing constitutive relationship at different super high strain rates. According to the theory of dislocation dynamics in Seeger equation, a dynamic shearing damage constitutive relationship was established and the different parameters of this material were determined by using the curve fitting method. The measured results indicated that the dynamic shearing property of high N alloy steel could be obtained effectively by the improved Hopkinson pressure bar system, and the effects of strain rate could be simulated by dynamic shearing damage constitutive relationship.