Applied Mechanics and Materials Vols. 651-653

Abstract: With silica-cerous of high activity as catalyst, ethylene glycol ethyl ether acetate was synthesized from ethylene glycol ethyl ether and acetic acid. The proper conditions for the synthesis were obtained by a single factor experiment and orthogonal experiment. Based on 0.3 mol acetic acid, the optimum conditions were as follows: the mass ratio of silica-cerous (15% loaded sulfate cerous) / acetic acid being 0.056 : 1, the mol ratio of acetic acid / ethylene glycol ethyl ether being1 : 1.2, the amount of cyclohexane being 30 mL, reaction temperature being 90 °C, and reaction time being 2 h. Such optimal conditions give the highest yield of 99.53 % and selectivity of 100 % of ethylene glycol ethyl ether acetate. Its structure was confirmed by IR, and the catalyst still has high activity after being reused for five times.

Abstract: A nickel nanowire catalyst was prepared by a hard templating method, and characterized by transmission electron microscopy (TEM), N₂ physical adsorption, X-ray photoelectron spectrometry (XPS), X-ray diffraction (XRD) and H₂ temperature-programmed reduction (H₂-TPR). The catalytic properties of the nanowire catalyst in the ethanol steam reforming were compared with a metallic Ni catalyst which was prepared with nickel sponge. The characterization results showed that the nickel nanowire catalyst had high specific surface area and there was more NiO phase in the nickel nanowire catalyst than in the metallic Ni catalyst. The reaction results showed that the nickel nanowire catalyst had higher ethanol conversion and hydrogen yield than the metallic Ni catalyst.

Abstract: The calculations of thermal equilibrium of B/O and B/C/H/O/N system were done based on the principle of Gibbs minimum free energy by HSC Chemistry software. The results indicated that in B/O system when B/O mole ratio is kept at 2:3, the main gas phase boron contained products transform from B₂O₃(g) to BO(g) and BO₂(g) with increase of temperature. Improving the environmental pressure is beneficial to increase the heat release of boron combustion. As to B/C/H/O/N system, B/C/H/O/N mole ratio is settled to be 2:1:2:6:1. The main combustion products are N₂(g), HBO₂(g), CO₂(g), H₂O and B₂O₃(g) when the environmental temperature is relatively low in the case that the heat release of fuel can be obtained enough. When the environmental temperature rises, the major combustion products are CO(g), BO(g) and so on. It shows that high temperature is not beneficial for heat release of boron combustion. Like B/O system, improving the environmental pressure helps to increase the heat release of B/C/H/O/N system combustion.

Abstract: In this paper, a series of semi-interpenetrating polymer network materials based on poly ((2-dimethylamino) ethyl methacrylate)/poly (N, N-diethylacrylamide) (PDMAEMA/PDEA) were synthesized at room temperature. The influence of this additive on the property of resulting PDEA materials was investigated and characterized. The glass transition temperature (T_g) of the semi-IPN materials was observed by Differential Scanning Calorimetry (DSC). Compared to PDEA, the semi-IPN materials exhibited excellent mutative values in response to an alternation of the temperature, and showed fast swelling and deswelling rates in response to temperature change, which suggests that these materials have potential application as thermal infrared camouflage materials.

Abstract: Two novel thiopyrano [4,3-d] pyrimidine derivatives 7 and 8 were synthesized from dimethyl 3,3'-thiodipropanoate through six steps including two times of cyclization, chlorination, oxidation, substitution with morpholine and piperazine and their structures were confirmed by ¹H NMR and MS spectrum. The total yield of the six steps was 18.6% (calculated from methyl dimethyl 3,3'-thiodipropanoate). The synthetic routes of them can be used to synthesize PI3K/mTOR inhibitors bearing a thiopyrano [4,3-d] pyrimidine nucleus.

Abstract: In order to synthesize the high performance and low cost boride composite powder, in this experiment the cheap raw materials ZrSiO₄ and CaCO₃ combining with H₃BO₃, carbon source (graphite or petroleum coke), and the agent for crystal type conversion are used to synthesize ZrB₂·SiC and CaB₆·B₄C compound via the fused and carbon thermal reduction method in the electric arc furnace (EAF). Different types of the fine composite powder are obtained by grinding the corresponding compound.

Abstract: Neodymium-doped gadolinium gallium garnet (Nd:GGG) precursor and ceramic were prepared by liquid phase co-precipitation or solid-state methods, and the properties were studied. The results indicate that the precursor prepared with the liquid phase co-precipitation method has a small particle size. The sub-transparent ceramic was obtained after the body sintered for 2-3h at 1650°C at 1100Pa using liquid-phase co-precipitation method. When the body was sintered at 1750°C for 2-3h, a sintered body with non-transparency was obtained. The absorption spectrum and fluorescence spectrum of the sub-transparent ceramic were measured with the cross section at 807nm was calculated as1×10-²⁰cm² and the strongest emission peak located at 1061nm.

Abstract: Temperature-responsive poly (N-isopropylacrylamide) (NIPAM_n) was grafted onto porous silica (Sil-NIPAM_n) to be used as stationary phase for normal-phase high performance liquid chromatography (NP-HPLC). Specific interaction ability and unique selectivity were detected between NIPAM_n and polyaromatic hydrocarbons (PAHs) through monitoring the retention time with increasing the temperature in NP-HPLC process. The results showed that Sil-NIPAM_n has better retention behaviors for structural isomers of PAHs when the temperature is above its lower critical solution temperature (LCST) in mixture of n-hexane/isopropanol. It indicates that NIPAM_n grafted on the silica shows phase transition from random coil to stretch state to increase interaction between solutes and stationary phase when temperature is above its LCST.

Abstract: The effect of different tungsten-bearing materials addition in a surface preform, such as Ni-base WC particles, ferrotungsten powders and casting WC particles, on the reinforcement phases at the surface compound layer with a carbon steel substrate is investigated under the condition of vacuum expandable pattern casting V-EPC. The microstructures and reinforcement phases are characterized by optical microscopy, SEM and EDS. Experimental results show that it is impossible to synthesize the independent WC particles in each condition. The tungsten-containing materials are all inclined to decompose during steel infiltration and the released tungsten elements tend to combine with carbon to form fish born-like or strip-like WC or W₂C carbides and dissolve in other type of carbides and matrix.

Abstract: Aiming to explain forming mechanism of copper pipe workpiece with inner straight groove via ball-rolling at different spinning speeds, the copper pipe workpiece and straight die is modeled in ABAQUS. And the whole simulation includes forming process, analysis of strain and stress. It is concluded that in the process of ball-rolling, the deformation of copper pipe workpiece is mainly the axial and teeth groove radial; with rotary extrusion increasing, the equivalent strain and stress enlarge gradually. Under the premise of keeping the quality of production, the maximum spinning speeds is 24000 r/min, which will not lose steady and complete the whole operation successfully. The simulation data and conclusion supply the basis for the actual processing.