Applied Mechanics and Materials Vols. 184-185

Abstract: Series of the triazene-cinnamic acid polymeric fluorescent brighteners were synthesized through three-step condensation reactions and polymerization reaction with styrene under replacing one of amino compounds of traditional fluorescent brighteners by cinnamic acid. The optical properties in aqueous solutions and N,N’- dimethyl formamide as well as paper coating application test were evaluated. The results showed that the light stability and fluorescence quantum yield of polymeric fluorescent brighteners was improved obviously and photoinduced isomerization was lower. Meanwhile the optical properties of polymeric fluorescent brightener were affected by concentration and solvent polarity, fluorescence quantum yield increasing and hypochromatic shift of fluorescence emmission wavelength with the decrease of solvent polarity. When the concentration was over 1 10-4 g/mL, the fluorescence was quenched.

Abstract: The tribological properties of polyphenylene sulfide (PPS) composites reinforced with carbon nanotube (CNT) and carbon nanofiber (CNF) were studied. Sliding tests in a pin-on-disk configuration were used to study the tribological properties. The wear rate of reinforced composites in the early part of sliding was lower than that of PPS but over extended sliding the reinforcement was not effective in reducing the wear rate. The coefficient of friction was not greatly affected by the presence of CNF and CNT. The lack of transition from run-in to steady state wear was attributed to the increased wear rates of PPS composites.

Abstract: In the present paper, thermomechanical controlled processing (TMCP) of low carbon cold heading steel was conducted by a laboratory hot rolling mill. The results have shown that the mechanical properties of the low carbon cold heading steel can be significantly improved by TMCP without heat treatment. The enhancement of the mechanical properties for the low carbon cold heading steel is attributed mainly to the finer ferrite grain size, and it is also related to the remaining dislocations within substructure of the cold heading steel after deformation. A technology is developed for producing hot rolled product of cold heading steel with improved mechanical properties. The technology has great significance because processing flow is simplified, and manufacture cost is decreased.

Abstract: In order to obtain a nanocrystalline and amorphous structure in the Mg2Ni-type alloy, the melt spinning was applied to fabricate the Mg20Ni7M3 (M=Co, Cu) hydrogen storage alloys. The microstructures of the alloys were characterized by XRD, SEM and HRTEM. The effects of the melt spinning on the gaseous and electrochemical hydrogen storage kinetics of the alloys were investigated. The results indicate that the as-spun (M=Co) alloys display a nanocrystalline and amorphous structure as spinning rate grows to 20 m/s, while the as-spun (M=Cu) alloys hold an entire nanocrystalline structure even if a limited spinning rate is applied, suggesting that the substitution of Co for Ni facilitates the glass formation in the Mg2Ni-type alloy. The melt spinning remarkably ameliorates the gaseous hydriding and dehydriding kinetics of the alloys. The hydrogen absorption ratio ( ) and hydrogen desorption ratio ( ) are enhanced from 81.9% to 94.7% and from 34.9% to 57.3% for the (M=Co) alloy, and from 57.2% to 92.8% and from 21.6% to 49.6% for the (M=Cu) alloy by raising spinning rate from 0 (as-cast was defined as the spinning rate of 0 m/s) to 30 m/s. Furthermore, the high rate discharge ability (HRD), the limiting current density (IL) and the hydrogen diffusion coefficient (D) of the alloys notably increase with the growing of the spinning rate.

Abstract: With the development of engineering technology, FEM can be used to simulate metal machining process and gain better understanding of material flow within dies, so as to optimize tooling to eliminate tears, laps and other forging defects. In this paper, numerical simulation was conducted by using FEM software on the whole cutting process for TC4 alloy mounting parts in an effort to investigate the metal flow behavior. The thermal simulation results obtained were compared with the cutting temperature and discussed in terms of literature data.

Abstract: Based on the calculation and analysis of three kinds of elastic beam’s stiffness coefficient in micro machined gyroscope, the results show: in the condition of small displacement，forces and displacement are linear relationship in clamped-clamped beam, crab-foot beam and bow beam; but as the displacement increases, the relationship between forces and displacement are obvious non-linear in clamped-clamped beam. When the displacement is three times the length of beam’s width, the bow beam’s force and displacement are linear relationship. By ANSYS crab-foot beam and bow beam’s stiffness is obtained, the simulation results and the polynomial fitting coefficient are all credible.

Abstract: In current research, WC dissolution phenomenon happened in TIG welds was investigated and discussed. And the element diffusion was studied using area-scanning method. The results showed that the WC dissolution phenomenon always happened near WC-Co/Welded seam interface. Moreover, the amount of WC dissolved in welds became less from WC-Co, welds to invar alloys. WC dissolution happened in welded seam induced by tungsten arc led to the WC grain growth (60µm or so) and WC shape changes. The grain boundary (GB) between different WC particles during WC aggregation was also confirmed and WC grain growth was owed to the WC aggregation during the processing of WC dissolution.

Abstract: The homocoupling reaction of alkynes was carried out smoothly in the presence of 10 mol% AuCl3 using I2 as oxidant to generate diyned products in high yields. The method is simple, efficient, safe and AuClPh3 also showed comparable catalytic activity to this transformation.

Abstract: Along with the wide applications of metal fibers in many fields, more and more attentions were paid on the preparation of metal fibers. Bifurcating chip cutting (BCC) is an effective method of manufacturing slim long metal fibers with high efficiency. In this paper, the chip-bifurcating states were studied in the process of BCC. The states can be classified into four kinds of circumstances according to the experimental results: thorough chip-bifurcating, incomplete chip-bifurcating, part chip-bifurcating and chip-bifurcating entirely but sticking together. Moreover, three chip-bifurcating criteria were proposed to keep the thorough chip-bifurcating state stable. The three chip-bifurcating criteria are found in good agreement with experimental results and can be used as a practical guide for producing slim long metal fibers by BCC.

Abstract: Abstract. The performances of underwear fabrics are good or bad is a concept of Physiology and psychology, comprehensive evaluation of its performances by fuzzy mathematics is objective and accurate. Fuzzy mathematics was used in this paper to establish comprehensive evaluation model, and on the basis of this model, the comprehensive evaluation on the performances of the four warmth underwear fabrics were made. The evaluation result indicated that the comprehensive performances of wool fiber covering bamboo fiber compound fabric are superior to pure wool fiber fabric and wool/ bamboo fiber blended fabric. These kinds fabrics are suitable for making high quality warmth underwear for autumn and winter.