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This paper is aimed to study the vehicle front-end structural design and provides the robust optimal method for engineering problem involving discrete design variables. First, the simulation model of SUV is constructed and the validity of the model is conducted by physical test. Then, the study is carried out by utilizing the successive Taguchi method to investigate the front-end structures on pedestrian lower leg protection and will provide foundation for engineering optimization. Last, the optimized design was prototyped for further physical test. The optimal results show that the performance and robust of the optimal design have some significant improvement. Compared to initial design, mean value and standard deviation for knee shear displacement have decreased 38.68% and 55.34% respectively. The value of SNR has increase from -16.595 to -13.390. According to the test results, knee shear displacement is reduced from 7.91mm to 4.84mm, and the value of upper tibia acceleration and knee bending angle satisfied the design requirements. The optimization of front-end structures demonstrated that the performance and robustness have been significant improvement. The method was considered to be suit for other more complicated engineering problems.

p-Type Zn doped (AlxGa1-x)0.5In0.5P layers have been grown on (001) GaAs substrates by metalorganic vapor phase epitaxy. The lattice constants have been carefully measured by X-ray double crystal diffraction. Mismatches between the substrates and epitaxial layers are observed in the direction corresponding to lattice contraction. The variation of fully-relaxed lattice constants calculated from symmetric (004) and asymmetric (115) diffraction shows that the contraction is related to both increasing inlet dopant flows and increasing growth temperatures. Secondary ion mass spectrometry is employed to analyze the elements in the epitaxial layers. The variations of Al, Ga, In and Zn components indicate that a decrease of In incorporation during the growth leads to the contracted lattice, although Zn atoms, which incorporate into the sites of In atoms during the doping, are smaller in covalent radius. The decrease is supposed to be caused by the competition between In and Zn atoms on the growth surface, which is well fit by the surface adsorption-trapping model. In addition, the suppression of Al and Ga incorporation by inlet dopant flows is observed. The possible cause might be the ethane generated by the pyrolysis of dopant source, which impedes the decomposition process of metalorganic sources of Al and Ga atoms.

Injuries to the lower extremities are one of the major issues in vehicle to pedestrian collisions. To evaluate pedestrian lower extremity protection, the Transport Research Laboratory Pedestrian Legform Impactor (TRL-PLI) test has been conducted according to the specifications in European Union (EU) regulation. At the same time, a Flexible Pedestrian Legform Impactor (Flex-PLI), which has flexible femur and tibia, is examined in European New Car Assessment Program (Euro-NCAP) rating system. To minimize injury risks of pedestrian lower extremity, this paper presents the design optimization of a typical vehicle front-end structure subjected to two different impact cases of TRL-PLI and Flex-PLI. Several approaches involving sampling techniques, surrogate model, multiobjective optimization algorithm and reliability analysis are introduced and applied. Four different basis functions of radial basis function (RBF) surrogate model are adopted for achieving more accurate solutions for structural optimization and reliability analysis. It shows that the accuracy of the basis function is different and the best one is selected for approximate the objective and constraint functions. In order to take into account the effect of design variables uncertainty, the reliability-based design optimization (RBDO) is conducted, and a Monte Carlo Simulation (MCS) is adopted to generate random distributions of the constraint functions for each design. The differences of the different Pareto fronts of the deterministic optimization and RBDO are compared and analyzed in this study. Finally, the reliability-based optimum design result is verified by using test validation. It is shown that the pedestrian lower extremity injury can be substantially improved for meeting product development requirements through the proposed approach.

It is highly desirable that efficient recoverable heterogeneous catalysts should be developed to replace the costly biocatalysts used in producing structured phospholipids (SPLs) with medium-chain fatty acids (MCFAs). Thus, mesoporous propyl and phenyl sulfonic acid-functionalized SBA-15 materials synthesized via surface modification methods were investigated for the soybean lecithin interesterification with methyl caprate or caprylate. The physicochemical properties of the synthesized solid acids were deeply studied by small-angle X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared and pyridine adsorption, etc. to build the possible structure&ndash, performance relationships. The results revealed that amounts of organosulfonic acid groups were successfully grafted onto the SBA-15 support, and most of the surface acid sites contained in the as-prepared organic&ndash, inorganic hybrid samples were assigned as strong Brӧnsted acid sites. Notably, the functionalized SBA-15 materials exhibited promising catalytic behaviors in producing MCFA-enriched SPLs under mild conditions (40 &deg, C, 6 h) when compared with commercial Amberlyst-15 and typical phospholipases or lipases, mostly due to their high surface area, ordered structure and adequate Brӧnsted acid sites. Besides, the as-prepared materials could be easily recycled five times without obvious deactivation. This work might shed light on alternative catalysts for SPL production instead of the costly enzymes.

Tellurium doped Al 0.13 Ga 0.39 In 0.48 P (AlGaInP) is an ideal material for the n side of an ultra-broadband tunnel junction for next generation 5J solar cell structures grown by metal-organic vapor phase epitaxy (MOVPE). Indium mole fraction is selected to reduce the lattice-mismatch and strain caused by the larger atomic size of tellurium when the AlGaInP must be highly doped for the electron states degeneracy. Growth pause at an elevated temperature after AlGaInP growth is employed to provide for a sharp turn-off, avoiding unintended compensation by donors in the subsequent p layer. The turn-on of tellurium is improved using pre-doping process during the temperature ramp before the growth. Electrochemical capacitance–voltage (ECV) result shows that uniform doping level of ~7×10 18 cm −3 is obtained in the n side of the tunnel junction with sharp edges at the doping interfaces. The tunneling current density of the fabricated tunnel junction is about 7.8 A/cm 2 .

5-junction solar cells with 2.05 eV top sub-cells are the most promising structure to achieve the conversion efficiencies beyond 36% (AM0, 25°C). Al0.13GaInP (Eg≈ 2.05eV) sub-cell is grown by metal organic vapor-phase epitaxy (MOPVE), presenting an efficiency of 10.04% with 1457.3 mV in Voc and 11.9 mA/cm2 in Isc (AM0, 25°C). External quantum efficiency (EQE) of the sub-cell reveals the poor AlInP/Al0.13GaInP interface passivation, therefore the Isc of the sub-cell is limited. GaInP/Al0.13GaInP het-ero-structure is employed to improve the IV charac-teristics, especially the Isc, by enhancing the spectral response of the long-wavelength region, and further to improve the overall Isc of the 5-junction solar cell. Preliminary GaInP/Al0.13GaInP sub-cell shows en-hanced efficiency of 10.16%, with the Isc increased to 12.6 mA/cm2 and the Voc decreased to 1398.12 mV.

Based on evaluation procedures of pedestrian protection (Euro-New car Assessment Program, Euro-NCAP), using CAE (Computer-Aided Engineering) and physical test, the pedestrian head impact safety performance was evaluated. Detailed analysis was done for Key factor which affect the performance of pedestrian head impact. The structure design optimization was performed of the front-end, including Hood, Fender and Cowl top for a SUV car. The final assessment results show that the optimized front-end structure meet the requirements of Euro-NCAP pedestrian protocol, in favor of the pedestrian protection performance improvement. Thereby, the paper provides best reference for the front-end structure design on SUV Cars.

Adaptive filter implementations require real-time conversion of coefficients to canonical signed digit (CSD) or similar representations to benefit from multiplierless techniques for implementing filters. Multiplierless approaches are used to reduce the hardware and increase the throughput. This paper introduces a novel hardware implementation method that converts two's complement numbers to their CSD representations using a fixed number of shift and logic operations. As a result, we can greatly reduce the power consumption and area requirements for hardware implementation of DSP algorithms in which coefficients are not known a priori. Because all CSD digits are produced simultaneously, the conversion speed and thus the throughput are improved when compared to overlap-and-scan techniques such as Booth's recoding.

An Al0.13GaInP sub-cell used as the top cell in the next generation of high efficiency multi-junction solar cells is fabricated. An efficiency of 10.04% with 1457.3 mV in Voc and 11.9 mA/cm2 in Isc was obtained. QE comparison was carried out to verify the influence of an O-related defect introduced by the high Al-content materials on the cell performance during MOCVD growth. Hetero-structures are employed to confirm the origin of the decreasing short circuit current density compared to a GaInP single junction solar cell. An effective method to improve the performance of broadband solar cells by increasing Isc with a cost of Voc was proposed.