Applied Mechanics and Materials Vol. 192

Abstract: A fine-grained granitic rock is utilized to study the effect of dynamic strain rates on failure response theoretically. Theoretical investigation employs a model that combines dynamic fracture criterion and damage mechanics theory. We simulated the damage evolution and the strain rate evolution when the rock failed under a dynamic load.

Abstract: Keap1 negatively regulates the function of Nrf2 that is a major activator of genes encoding phase 2 detoxifying enzymes via sequestering cytoplasmic Nrf2 and subsequent degradation through the proteasome system. Reactive cysteine residues of Keap1 could be modified by Michael reaction acceptor molecules. Previous studies have shown that adduction at Cys151 by diethyl maleate (DEM) can give rise to a significant conformational change in Keap1 that leads to the dissociation of Keap1 from CUL3, hence inhibits Nrf2 ubiquitylation. The BTB domain of Keap1 plays a crucial role in both forming self-dimerization and binding to CUL3. In order to better understanding the molecular mechanism how DEM interact with amino acid residues around Cys151, we performed two molecular dynamics (MD) simulations including Keap1-DEM complex and Keap1 alone (control group). Interestingly, we found that after a short period of lingering around Cys151, DEM ultimately stabilized in a gap between two specific helixes away from the cavity around Cys151 and induced a concomitant significant conformational change of BTB domain of Keap1. Similar phenomenon, however, was not observed in the control group. These results suggested that DEM could impair the normal function of Keap1 by inducing the conformational change of BTB domain via direct noncovalent bonded interaction. Our research provides a new insight into another way of interaction between Keap1 and DEM in spite of their known Michael addition reaction, by which novel phase2 enzyme inducer drugs with higher specificity could be discovered in the future

Abstract: In this research, paper material with different performance (e.g. brightness, fiber type, filler retention, coating weight, etc.) is the main subject. According to analysis of physicochemical properties for paper material and experimental results for corresponding printing qualities, the research presents the relationship between paper optical property and printing quality. And on that basis, it also pays more attention to optical effects (such as reflection, scattering, absorbing, concentration) and mechanism of paper with different brightness, research on best visual brightness, contrast and so on, which reveals vision laws among paper optical performance, printings and humans.

Abstract: This article briefly describes the development of dye intermediates in China and the research and development situation on synthetic 2 - amino-5 - nitrobenzoic acids. It also tries two more new routes to practice synthesis of them, for which it focuses on speculation of the reaction mechanism of the former route and on research of process conditions of the latter, getting the optimal conditions of the synthetic 5 - nitro-isatin. 2 - Amino - 5 - nitro benzoic acid is a versatile organic intermediate, which is seldom reported both home and abroad, but research on its synthesis method and process conditions are significant to the development of China's fine intermediates industry.

Abstract: The paper takes self-developed great aqueous inking oil formulated into screen-printing aqueous ceramic ink under glaze color of once firing as the breakthrough point to choose proper decal paper and the best paper structure. It adopts modern screen-printing technology and searches new production process of ceramic decal under glaze color to solve some problems, such as the uselessness of fine lines, the mistakes of the short line, fault ink and color problem during delicate screen-printing and appliqué, and the defects of injury of glaze during appliqué, and to research new and high-grade screen-printing ceramic decal paper under glaze color of once firing.

Abstract: Straight TC4 wire rod is demanded by many industries, however the technology of straightening for it has not been solved. In the present paper, a horizontal-vertical roller thermal straightening system is designed and the theory of rolling reduction is concluded. Based on the new system and the rolling reductions calculated for each roller, the method of finite element analysis is used to show the process of straightening at 600°C. The result of straightening is ideal, which proves the straightening system is adequate for Φ4.5 TC4 wire rod.

Abstract: The purification and characterization of an alkaline protease produced by Bacillus alcalophilus were investigated. The enzyme was purified in two steps: concentrating the crude enzyme using ammonium sulfate precipitation, followed by cation-exchange chromatography. The purified protease had a molecular mass of approximately 28 kDa, was highly active over an alkaline pH range of 10.0 to 11.0, and remained stable over a pH range of 7.0 to 12.0. The optimum temperature for the enzyme activity was found to be 40~60°C, while the thermotolerance of the enzyme was poor. Therefore, these characteristics of the protease indicate its potential for a wide range of commercial applications.

Abstract: Multi–walled carbon nanotubes (MWNTs)/polyethylene (PE) nanocomposites were prepared via in situ polymerization with MWNTs supported Cp2ZrCl2 catalyst. XPS and FESEM results imply that Cp2ZrCl2 catalyst has been immobilized in the surface of the MWNTs supports by a MAO bridge. The efficient dispersion of MWNTs in PE matrix and the strong compressive forces associated with PE on the MWNTs were demonstrated by TEM, FESEM and Raman spectra. With introducing 0.2 wt.-% MWNTs, both the tensile strength and elongation of MWNTs/PE nanocomposite increased by factors of 1.6 (from 29 MPa to 45 MPa) and 1.5 (from 909% to 1360%) comparing with the pure PE, respectively. Morphology observation of fractured surface, in accordance with the Raman results, revealed that the PE firmly adheres to the nanotubes, which is responsible for the significant improvement of the mechanical properties of nanocomposites. Thermal stabilities of the nanocomposites were significantly improved. In addition, the MWNTs/PE nanocomposites show very high UV shielding properties, which could increase photooxidative stability of the PE.

Abstract: This paper started with the performance of ordinary transformer oil, and then compared the Nano-modified vegetable oil with transformer oil. From the comparison of results, the author drew a conclusion that Nano vegetable oil must have broad prospects in the use of the transformer.

Abstract: The air and missile defense warhead is the final unit of destroying target. The evaluation index of warhead is referred to what its combat mission is to achieve the desired target degree in the prescribed conditions and time. It’s also the main index with performance of the air and missile defense. According to the characters of air and missile defense warhead, the evaluation index system of warhead is given. The effect function is introduced to quantitate the evaluation index, and the function equation is given to fit the air and missile defense warhead. On this foundation, the evaluation model of operational effectiveness based on LMBP neural network is presented, then it is validated that the model has a higher value by an example.