Applied Mechanics and Materials Vol. 733

Abstract: In this work, the physicochemical property and its Effect of hydrous amorphous cellulose has been studied using molecular dynamics. Both intramolecular and intermolecular hydrogen bonds in cellulose molecules decrease with increasing water content, directly leading to the decline of cellulose cohesive energy density, solubility parameters, and mechanical parameters. High water content in amorphous cellulose gives bigger interchain distance of cellulose molecules, indicating that the intermolecular interaction of cellulose molecules is weakened greatly by water.

Abstract: Discussed the characteristics of iridium generally, illustrated the importance of exploring and studied the plasticity about iridium. We analyzed high temperature plasticity about Nb alloying effects based on first-principles density functional theory. Calculated cohesive energies and formation enthalpies of IrXNb32-X in different amounts of Nb, then calculated and analyzed elastic constants of IrXNb32-X, and finally summarized the influence of Nb addition in Ir on high temperature plasticity.

Abstract: Macroporous resin was the most common method for the separation and purification of steviosides. But the purity was only 90% influenced by less selectivity of the resin. And Rebaudioside A could not be separated from other steviosides at the same time. Purity of total glycosides could be up to 99% and Rebaudioside A could be enriched efficiently by section desorption after one-dimensional chromatography of macroprous resins. The content of Rebaudioside A increased from 39.46% to 63.70% gradually in each desorption solution of the 4 resin columns. Moreover, the resolution between Rebaudioside A, Rebaudioside C and stevioside, and the number of theoretical plates for them were detected meanwhile. These results could provide theoretical foundation for the separation of high purity steviosides and enrichment of Rebaudioside A.

Abstract: With boron trifluoride methanol complex as raw material, the hydrolysis reaction of boron trifluoride was used to prepare the boric acid. The addition of calcium carbonate is aim to remove the hydrogen fluoride generated in the reaction process, The ultimate objective is making the material being the product of boric acid maximum. Reaction time (T), the ratio of raw materials (molar ratio) and the amount of water were investigated in the influence of the purity and yield of boric acid. The conductivity of mixed solution was determined by conductivity meter, the results determines the end point of the reaction for 20 hours, the optimum solid-liquid ratio is three to one, the amount of water for each mole of boron trifluoride is corresponding 2L distilled water. Product of boric acid yield was 96.26%, the purity was 95.34%.

Abstract: The effect of residence time on biomass pyrolysis is discussed in the paper. Firstly, several typical temperature nodes (573, 873, 1073, and 1273K) are selected as the experimental subjects. Then, the residence time is changed in these temperature nodes. Finally, thermo gravimetric analyzer is used to study the pyrolysis and kinetics characteristics of biomass in different experimental conditions. The results show that extension of residence time is not conducive to biomass mass loss and heat release at 523, 873, 1073, and 1273K. In the several temperature condition that the faster heating rate and the shorter residence time, the more weightlessness is and the phenomenon is more obvious in low temperature. With the increase of the residence time, area and value of the second endothermic peak decreases and the value moves to high temperature zone. When the residence time is not the same value, the biomass pyrolysis can still be fitted for two first-order kinetic equations. At the same time, temperature interval length of fitting curve decreases and further leads to E and A increase.

Abstract: Basic magnesium chloride whisker is described as a cheap and available whisker material. The preparation and application prospect of basic magnesium chloride whisker were introduced in this paper, and the use of abundant concentrated seawater or brine resources in the preparation of basic magnesium chloride whisker was prospected.

Abstract: Three-phase secondary rectification spot welding machine had been adopted to join 5A90 Aluminum-lithium alloy with a thickness of 2 mm, at different welding conditions. The mechanical properties of the lap joints were investigated and microstructure were analyzed respectively. The results showed that the joint fabricated at a welding current of 45.5 kA, welding time of 4 cycles, and electrode pressure of 8.55 kN exhibited higher tensile-shear force value of 7.7 kN compared to the other joints. The nugget were mainly composed of equiaxial grains and cellular dendrites. Meanwhile, equiaxed zone can be divided into the equated dendrites, the wormlike eutectic structure and few equiaxed non-dendrites. The tensile fracture surfaces exhibited a hybrid ductile-brittle fracture, while Al3Li strengthening phase lied in the bottom of dimple.

Abstract: A new solid proton conductor Na7[CoCrW11O39 (H2O)]·15H2O has been synthesized for the first time. The percentage composition of the product were determined by inductively coupled plasma (ICP) and X-ray photoelectron spectroscopy (XPS). The product was characterized by infrared spectroscopy (IR) and X-ray diffraction (XRD), which indicate it possesses the Keggin structure. The TG-DTA curve shows the sequence of water loss in the compound, the amount of the loss, as well as the thermostability. Conductivity of the compound was investigated by four-electrode method at room temperature and different measuring temperatures, the results reveal that its proton conductivity is 9.42×10−7S·cm-1 at 25°C.

Abstract: The microwave digestion-ICP-AES was used to detect the Cr, Cd, Pb, As, Hg and Ni in cordycepsmilitaris from Shenyang. The method accuracy was proved by the national standard method. The result shows the sequence of heavy metals was Pb>Ni >As > Cd> Cr, and Hg was not detected, as was detected in few sample. All the data showed that cordycepsmilitaris accords with the national standards. The method average recovery is 94.07%-107.58%, and RSD is 0.84%-3.25%. It is a promising analysis method on detection of heavy metals in cordycepsmilitaris.

Abstract: This paper integrated systematically the method of MFA, DEA, and the evaluation method of eco-efficiency, constructed a method of evaluating total factor non-renewable energy efficiency based on the perspective of green growth. And it defined the indicators system of evaluating total factor non-renewable energy efficiency. This paper gave an empirical research of total factor non-renewable energy efficiency, economic efficiency of non-renewable energy, environmental efficiency of non-renewable energy, and eco-efficiency of non-renewable energy, of Chinese provincial regions for the year 2012.Study results confirms: the method of evaluating total factor non-renewable energy efficiency of this paper, not only discussed the evaluating problem of total factor non-renewable energy efficiency of the process of non-renewable energy using, but also brought economic value, environmental influence and ecological cost into evaluating framework of total factor non-renewable energy efficiency; so it is a scientific and comprehensive tool of evaluating non-renewable energy efficiency, and is in conformity with the idea of green growth.