2017 Vol. 32, No. 5
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The scavenging effects of Maillard reaction products (MRPs) derived from L-lysine-D-arabinose against on hydroxyl radical (·OH), superoxide anion radical (O2-·) and DPPH radical(DPPH·)under different reaction temperatures, reaction times, initial pH values and substrate molarratios were investigated,and the reaction conditions were optimized by uniform optinized experiment.Under the optimum conditions, the free radical scavenging rates for MRPs against ·OH, O2-· and DPPH· were 47.28%,75.16% and 89.81%, respectively. Therefore, the MRPs derived from L-lysine-D-arabinose could not only be used for food coloring and flavor enhancement, but also help to prevent the diseases caused by various free radical damages in vivo.
The changes law of microbial flora during Sanchuan ham processing was studied, and the dominant bacteria was further identified by morphological and physiological and biochemical tests. The results showed that the curing period, dry period and ripening period were the stages of rapid increase, steady growth and reduction of total bacteria and Staphylococcus on the surface and inside of Sanchuan ham, respectively.The total Pseudomonas count on the inside of Sanchuan ham was higher than that on the surface during the whole processing, revealing a decreasing trend due to the competitive growth between microorganisms (except for the early curing period). The total Yeast count on the surface and inside of Sanchuan ham increased during the late curing period, but substantially decreased during ripening period. The identified dominant bacteria were Staphylococcus equorum and Staphylococcus simulans.In ham processing strengthening the control of time and temperature in the curing and dry period could help form precursor substance to further the unique flavor formation of ham in ripening period.
The dietary fiber (DF) was obtained from Shanxi millet bran by thermostable α-amylase, glucoamylase and neutral protease.Then the SDF was prepared from DF by the method of complex enzyme (cellulose-xylanase) modification. The enzyme modification process was further optimized by the response surface design based on the single factor experiment.The optimum process conditions were as follows:total amount of complex enzyme1.73%,ratio of cellulose and xylanase 1:1.74, hydrolysis temperature 50℃,hydrolysis time 1.44 h. The SDF and IDF yields were 12.46% and 85.12% under this condition,respectively. The optimization design accurately predicted the yield of SDF obtained from millet bran DF. Importantly, the process operation was simple and required no special equipment, which possessed certain theoretical and practical significance for the comprehensive utilization of millet bran and the industrialization of SDF.
A large amount of size tunable zeolitic imidazolate framework-67 (ZIF-67) was synthesized in a shot time with ultrasonic assisted method. The structure and morphology of synthesized materials were characterized with XRD and SEM. Nitrogen adsorption-desorption technique was also used to characterize the synthesized ZIF-67.Results showed that the ZIF-67 prepared by this method had higher crystallinity, regular rhombic dodecahedral morphology, and higher porosity and specific surface area.As supercapacitor electrode materials, cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD) measurements were carried out to test the electrochemical performance of synthesized materials.The results showed that ZIF-67 synthesized by ultrasonic assisted method delivered a specific capacitance of 93 F/g at 0.5 A/g, which was much higher than that of ZIF-67 synthesized under static condition.When current density was 1 A/g,the specific capacitance of ZIF-67 synthesized by ultrasonic assisted mehtod could be retained to 98.6% of the initial value after 1000 cycles, demonstrating the excellent cycling stability.
The research progress of porous metal-organic frameworks (MOFs) materials that target for the gas storage and separation was introduced, and its application in CO2 storage/separation and C2H2 gas storage was summarized. It was pointed out that MOFs materials with different pore properties had different effects on CO2 storage and separation and C2H2 gas storage, the performance of the composites could be controlled by controlling the size, shape and functional groups of the MOFs materials. At the same time,the structure-activity relationship of the synthesiczed material by means of single crystal diffraction technique and in situ characterization so as to optimize the performance of MOFs materials.However,most MOFs materials have poor water stability,which could be improved by using an organic ligand containing a hydrophobic group and a high-valent metal cluster (e.g., Cr3+, Zr4+, etc.) as a molecular-based building unit of MOFs materials.The adsorption selectivity of MOFs materials to specific gas had a large room for improvement, and this problem could be achieved by designing and synthesizing MOFs materials with dynamic adsorption behavior.In addition, the use of molecular simulation technology could really put the structure and function of the material to the design level in the future, thus saving experimental costs.
The hexagonal wurtzite Gallium nitride(GaN) was prepared by calcining β gallium oxide(β-Ga2O3) in flowing ammonia. The XRD, SEM and TEM were employed to investigate the structure and morphology. The photoluminescence (PL) spectroscopy was used to collect photoluminescence spectroscopy of GaN perform the luminous property. The measurement results revealed that the obtained GaN had preferred orientation of (002), and the rod shape and grain size of GaN powders were similar to those of raw gallium oxide which were agglomerates of tens nanometers flake crystallites. The near-edge emission at 346 nm(3.584 eV) of Gallium nitride powders had a blue shift of 19 nm(187 meV) than that of bulk GaN material.
Porous anodic alumina (AAO) film was prepared by using two anodic oxidation method and aluminum as template. The microstructure of AAO film was observed by atomic force microscopy. The effects of annealing treatment, electrochemical polishing treatment, anodizing voltage and anodizing time on the structure of AAO film were analyzed. The results showed that the AAO film was amorphous phase, but after high temperature annealing of the AAO film would be part of the crystal phase.The electrochemical polishing of the AAO film pore structure could improve the evenness of pore distribution. When the oxidation voltage was in the range of 40~55 V, pore size of AAO film increased with increasing of anodizing voltage, orderly arrangement of film pore structure had also been enhanced, and the pore size of the membrane pores was between 40 nm and 100 nm. Anodic oxidation time had no significant effect of pore size on the film. When the electrolyte temperature was 0~20℃, pore size of AAO film decreased with increasing of the electrolyte temperature, order degree of AAO film also increased.
In order to further improve the vehicle dynamic performance and fuel economy of ISG hybrid electric vehicle,after parameters matching of powertrain system,advisor software was used to build the vehicle simulation model to verify the feasibility of parameters matching and parts selection.On this basis,transmission main reduction ratio of transmission ratio and transmission of the file were selected as the optimization variables,the related dynamic performance requirements as the constraint conditions,particle swarm optimization (PSO)was used to optimize transmission parameters.Simulation results showed that the maximum climble gradient after optimization increased by 4.3%,fuel consumption per 100 km decreased by 0.8 L,0~100 km/h acceleration time decreased by 1.4 s.
Taking FSAE formula racing CBR600 engine as the research objective and based on the theory of hydrodynamics,by analyzing the cause and location of the energy loss of the engine intake air,the relevant structural parameters of the intake system were initially set.The two-dimensional model of the racing engine was established by GT-Power software,simulation analysis was conducted to determine the optimum value of intake pipe length as 300 mm and the best regulator cavity volume as 3.5 L.The model of the air intake system was established by Catia.The Fluent software was used to simulate the flow field of the intake system and the elliptical cylider regulator cavity could be obtained by comparing the pressure and velocity diagrams.The experimental results showed that the air intake system could meet the needs of the CBR600 engine and improve the air intake performance by about 5% to 10%.
In order to lengthen the life span of four-level-damping adjustable hydraulic shock absorber, the optimization design of the shock absorber was carried out by simulation technology. Its simulation model was established, the fluid dynamics simulation of valve was carried out by ICEM CFD pretreatment software and ANSYS Fluent fluid analysis software in order to obtain the stress and internal fluid flowing speed data of the valve under the corresponding piston movement speed. The optimization design of changing the non-step symmetrical through hole of piston hole of shock absorber to shoulder hole in order to increase the flowing area of fluid was proposed. The performance tested was made in the characteristics of damping, reactive power and speed. The result showed that the improved shock absorber improved in every aspect and could lengthen the life span, which verified the feasibility of the optimization design.
Aiming at the problem of lightweight design of door-leaf carrier of EMU sliding plug door,based on the finite element analysis and parametric articles of door-leaf carrier,the radial basis function was used for an approximate model based on the radical basis function was constructed.Then by combining the global superiority of multi-island genetic algorithm and the high efficiency of NIPQL approximate model was optimized.The strengh check results showed that the total weight of the door-leaf carrier was 11.356 kg,decreased by 10.6%,the maximum stress under three working condition was 93 MPa,which satisfied stree requirement.This lighweigh design was suitable.
In view of the poor performance of the present most palmprint recognition for single training sample system,a principal components analysis method for single training sample palmprint recognition was presented,which combined multi-subbands of wavelet transformation.This method combined wavelet low frequency subband with horizontal and vertical subbands to identify.Low-pass filter was utilized to enhance the robustness of horizontal and vertical subbands,and the summation operator was used to fuse their matching scores.Experimental results showed that for single training sample palmprint recognition the average recognition rate of the proposed method was 89.93%,which was 6%~9% higher than some of the traditional algorithms.
Due to the fact that the color of sugarcane nodes and internodes are similar to each other,and the interference of white fruit powder on the skin,node recognition and location were affected seriously.A method for node identification and localization was proposed based on hyperspectral imaging.236 sugarcane samples (874~1734 nm) were collected by the hyperspectral imaging acquisition system.Using successive projections algorithm (SPA) to extract characteristics band (1022 nm,1062 nm,1456 nm,1609 nm and 1649 nm),the PLS discriminant model were established by these 5 characteristic bands.The 20 groups of sugarcane hyperspectral images were identified by the established model,the binary image of sugarcane was gotten,image processing was used to locate the position of node.The experimental result showed the standard deviation was 0.7 mm,the maximum absolute error was 2.6 mm,and it could identify and locate the sugarcane node effectively,provide technical support for automatic cutting of sugarcane which could prevent injury buds.
In view that traditional mining δ free sets algorithm exist generating candidate itemsets,traversing all direct subsets,and so on leading to low efficiency,a free sets determine lemma and a fast mining free sets algorithm FMFS were proposed.FMFS used Rymon setenumeration tree as searching space and combined with pruning strategy,and then used the free sets determine lemma to quickly determine the candidate itemset.Experimental results showed FMFS algorithm not only mined all free sets,but also showed better performance than existed mining algorithm.
Founded in 1986, bimonthly
Administered by:The Education Department Henan Province
Sponsored by:Zhengzhou University of Light Industry
Editor-in-chief:Wei Shizhong
Executive Editor-in-Chief:Zou Lin
Deputy Editor-in-Chief:Qu Shuanghong
Edited & published by:Editorial Department of Journal of Light Industry
CN 41-1437/TS
ISSN 2096-1553
Address:136 Science Avenue, Zhengzhou City, Henan Province, China
Postal Code:450001
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