Advanced Materials Research Vols. 472-475

Abstract: The urethane reaction kinetics of 1,2-propanediol and 1,3-butanediol with phenyl isocyanate are investigated in toluene. In-situ FT-IR is used to monitor the reaction to work out rate constant. The urethane reaction has been found to be a second order reaction and is largely accelerated with triethylamine as catalyst. Furthermore, the rate constants are different between initial stage and final stage when triethylamine is used as catalyst, which belongs to different hydroxyls in asymmetry diol. However, when there is no catalyst in the reaction system, the rate constant is the same. That is, there is no reactivity difference for hydroxyls in asymmetry diol. Moreover, 1,3-butanediol is more active than 1,2-propanediol when reacting with isocyanate.

Abstract: In order to improve the quality of product design, reduce the cost, shorten the development cycle, virtual prototyping technology is used in the process of on the three point support type clutch press mechanism. The design scheme is rapid implemented through establishing three-dimensional modeling, assembly and disassembly, adjustment mechanism simulation, motion simulation of mechanism. So that the physical, mechanical performance of mechanism is analysised, simulated, predicted. Through the virtual operation simulation, early detection of defects in design, to realize optimization design.

Abstract: In this work, the effect of aluminum back surface field formed by screen printed various amount of Al paste on the effective rear surface recombination velocity (S_eff) and the internal rear reflectance coeffeicient (R_b) of commercial mono-silicon solar cells was investigated. We demonstrated the effect of S_eff and R_b on the performance of Al-BSF solar cells by simulating them with PC1D. The simulated results showed that the lower S_eff could get higher open circuit voltage (V_oc), at the same time, the larger R_b could get higher short-circuit current (I_sc). Experimentally, we investigated the S_eff and R_b through depositing Al paste with various amount (3.7, 5, 6, and 8 mg/cm²) for fabricating Al-BSF mono-silicon solar cells. Four group cells were characterized by light I-V, spectral response, hemispherical reflectance and scanning electron microscope (SEM) measurements. It was found that, a minimum S_eff of 350 cm/s was gotten from the cells with Al paste of 8 mg/cm², which was extracted by matching quantum efficiency (QE) from 800 nm to 1200 nm with PC1D, and a maximum R_b of 53.5% was obtained from Al paste of 5 mg/cm² by calculating at 1105 nm with PC1D. When the amount of Al paste was higher than 5mg/cm², there were less S_eff and lower R_b. On the other hand, when Al amount was 3.7mg/cm², it was too little to form a closed BSF. Based on the SEM graphs and simulations with PC1D, a simple explaination was proposed for the experimental results.

Abstract: Metal oxide varistors referred to as MOV were widely applied due to its excellent non-linear volt-ampere characteristic. In spite of its predominant function and using, MOV is always failed in value due to the increased temperature of MOV itself under an applied external field. The varistors assembly with an fusible alloy type thermal cutoff (called TMOV as follows) was designed in this paper, and it can make MOV avoid over-heat from degradation, failure and thus can prevent from fire hidden trouble, which was confirmed by experiments. It is really a very important technological improvement and breakthrough in over-heat protective field of MOV.

Abstract: Abstract: In recent years, geosynthetics are used and considered by many scientists for various earth structures. This is due to their good performance and ease of execution. Many researchers carried out extensive studies on the behavior properties of geosynthetics. However, much attention has not been given to detailed studies and investigation on bearing capacity of interfering shallow-foundations supported by geogrid reinforced sand. In this research, a series of experimental tests was carried out on the effects of geometrical parameters on bearing capacity of interfering shallow foundations supported by geogrid reinforced sand. A numerical model and design charts were introduced to predict bearing capacity. The results showed that the bearing capacity increased using geogrid reinforcement and a good correlation exists between the model and the conventional theoretical relations. Also, the main parameters affecting on the values of the interference factor were the footing distance (s/B) and the number of reinforcement layers (N). However, the suggested interference factor model had an effective reflection on the calculated bearing capacities of the footings.

Abstract: The upsetting process of cylindrical forging was investigated using finite element method. The influence of conical anvil on deformation rule of metal and distribution of strain and stress was studied using software MSC. Marc. The simulated results indicated that it had a smaller rigid zone and more homogeneous deformation zone in the billet during upsetting process with conical anvil compared with flat anvil. The critical reduction in height which could assure the three dimensional compressive stress states for the upsetting with conical anvil was smaller than that for the flat one.

Abstract: Classical least square (CLS) algorithm is applied in this thesis to develop the raw spectra corrected peak area model, the raw spectra corrected peak height model, the 2^nd derivative spectra corrected peak area model and the 2^nd derivative spectra corrected peak height model by NIR spectra data of the wheat flour samples with lime added in. The result indicated that the correlation coefficients of the 4 models are 0.9321, 0.9483, -0.9491 and -0.9482 respectively; the result of F-test indicated that a remarkable correlation exists between the specified values of lime in wheat flour and the the raw spectra corrected peak areas / heights or the 2^nd derivative spectra corrected peak areas / heights, which indicated that CLS algorithm has a certain potential application in the quantitative analysis of lime in wheat flour by NIR spectra data. Meanwhile, the result of F-test indicated that a very remarkable correlation exists between the estimated and specified values both the calibration set and external validation set of the 4 models. The limit of detection of the 4 models are 4.83 %, 4.14 %, 4.14 % and 4.17 % respectively, which will be suitable for the rapid quality screening for the wheat flour in the market and will be of great importance to the quality screening of wheat flour in the market, guarantee of the customers' health and the design and manufacturing of the special NIR spectrometer.

Abstract: The biodegradation and biodegradable mechanism of the polyesters ,such as poly (lactic acid) (PLA), poly (butylene succinate) (PBS) and poly (caprolactone) (PCL) have been investigated; the soil of Shanxi local land and activated sludge from Ningde waste water plant played the biodegradable medium in this study. The results shown the remarkable eroded trace of the surface of the films could be found after degradation by the results of Polarized Light Microscope (PLM) and scanning electron microscope (SEM); the biodegradation of PCL is best, the PLA′s is better than that of PBS. The structures of the films determined with Fourier-Transformation Infrared Spectrum (FT-IR) after degradation.

Abstract: Aiming at the issue on the development of gear form grinding machine, a method for analyzing the dynamic behaviors of the machine column was introduced. Based on the model of gear grinding machine developed before, a suitable finite element model of the column was established firstly. Modal analysis on the column was carried out by means of ANSYS software, and the first five natural frequencies and vibration modes of the column were obtained. According to the analysis results, some improvements on the original column structure were made. By comparing the static and dynamic behaviors of several different rib structures presented, the best column structure is selected. This method offers theoretical basis for the structural improvement of gear grinding machine.

Abstract: As for the techno -interface of CC-HR region, the precipitation and dissolution of carbonitride in Nb micro-alloyed steel E36 were studied during continuous casting, roller conveying, stack cooling, heat-preserved and heating units in typical slab process flow by hot simulation experiment based on study of heat transfer. The results are as follows: Ti(C,N), and (Ti,Nb)(C,N) precipitate in turn in continuous casting and conveying. A few (Ti,Nb)(C,N) particles are not solid solute completely after heating. The precipitation of carbonitride is effected significantly by different cooling rate in conveying. When slab conveied at the rate of 6.00 °C/min and then cooled down to 600°C, the distribution density of carbonitride particles is higher, and the average equivalent diameter of carbonitride particles is smaller, some carbonitride particles distribute along the austenitic grain boundaries and the generation elements of carbonitride particles are under over-saturation state. When slab conveyed at the rate of 0.30 °C/min or 0.15 °C/min and then cooled down to 400°C, the distribution density of carbonitride particles is lower, and the average equivalent diameter of carbonitride particles is bigger, the carbonitride particles precipitate fully. The behavior of carbonitride in slab are effected by different thermal history in heating. The status of carbonitride is effected insignificantly by different thermal history after heating.