Editor in chief：朱立光
International standard number：ISSN 1008-1542
Unified domestic issue：CN 13-1225/TS
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2016, 37(3):213-219. DOI: 10.7535/hbkd.2016yx03001
Abstract:In order to investigate change rule of the residual life of structure under random repeated load, firstly, starting from the statistic meaning of random repeated load, the joint probability density function of maximum stress and minimum stress is derived based on the characteristics of order statistic (maximum order statistic and minimum order statistic); then, based on the equation of generalized σ -N curved surface, considering the influence of load cycles number on fatigue life, a relationship among minimum stress, maximum stress and residual life, that is the σmin(n)- σmax(n)-Nr(n) curved surface model, is established; finally, the validity of the proposed model is demonstrated by a practical case. The result shows that the proposed model can reflect the influence of maximum stress and minimum stress on residual life of structure under random repeated load, which can provide a theoretical basis for life prediction and reliability assessment of structure.
2016, 37(3):220-229. DOI: 10.7535/hbkd.2016yx03002
Abstract:Software receiver has become a research hotspot in the satellite positioning receiver field because of its good universality, flexibility, and positioning performance. The structural features of software receiver and the current research status at home and abroad are formulated, and the structures and performance of PC-based, DSP(digital signal processor)-based, FPGA(field programmable gate array)-based and FPGA+DSP-based software receivers are compared and analyzed. It is pointed out that the FPGA+DSP- and DSP-based implementation can better demonstrate the advantages of software receiver, and realize its real application. Finally, the development directions of software receiver in the future and its application prospect in unmanned driving technology are put forward. The paper can provide theoretical references for software receiver's research and application.
2016, 37(3):230-237. DOI: 10.7535/hbkd.2016yx03003
Abstract:At present, the research on static and dynamic characteristics of hydrostatic supports depend on the form and structure of the restrictor, which are mainly focused on the influences of recess shape, bearing structure, bearing surface roughness, lubricant and elastic deformations of the bearing. There are few studies on the thermal effect of hydrostatic supports and static and dynamic characteristics of hydrostatic guideways. The research on motion errors of hydrostatic supports is primarily based on the static equilibrium of the moving part. The effects of the motion speed of the moving part and structural deformation on the motion errors are not considered. Finally, the research prospects from the standardization, modularization and industrialization of hydrostatic supports, thermal effect of hydrostatic bearing, the static and dynamic characteristics of hydrostatic guideways and motion errors of hydrostatic supports under operating conditions are concluded.
2016, 37(3):238-244. DOI: 10.7535/hbkd.2016yx03004
Abstract:In order to improve the photocatalytic properties of ZnO, the cyclized polyacrylonitrile(CPAN) modified zinc oxide(ZnO) nanocomposites are prepared by impregnation method. The size, morphology, internal structure of ZnO/CPAN nanocomposite and ZnO nanoparticles are characterized by means of X-ray diffraction (XRD)，transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The UV-light photocatalytic activity of ZnO/CPAN is evaluated with methyl orange as model pollutant under UV-light irradiation. The results of photocatalytic experiment show that the CPAN modified ZnO can significantly improve the UV-light photocatalytic activity of ZnO particles. When the mass ratio of ZnO/CPAN is 1 000∶1, the heat treatment temperature is 150 ℃, and the heat treatment time is 30 min, the photocatalytic activity is the highest.
2016, 37(3):245-248. DOI: 10.7535/hbkd.2016yx03005
Abstract:To improve the synthesis method of P005091 (1-(5-((2,3-dichlorophenyl) thio)-4-nitro-2-thienyl) ethanone), with 2-chlorothiophene as the starting material, acetyl chloride as the acetylation reagent and aluminium trichloride as the catalyst, acetyl is introduced in the 5th position of 2-chlorothiophene to get 2-acetyl-5-chlorothiophene (compound 2), and the yield is 91%; then with concentrated sulfuric acid as solvent and mixed acid as nitrating agent, 5-acetyl-2-chloro-3-nitrothiophene (compound 3) is obtained by nitration reaction with compound 2, and the yield is 64%; thioetherfication reaction of compound 3 and 2,3-dichlorobenzenethiol in DMF solution under the function of potassium carbonate takes place to obtain the target product P005091, and the yield is 76%. The structure of P005091 is confirmed by mp, 1H-NMR, 13C-NMR and MS, and the overall yield is 44%. The improved method has the advantages of low cost, simple operation, and a milder reaction condition compared with the former references, avoiding using the reagent with higher toxicity, and high yield on the premise that the product purity is assured.
2016, 37(3):249-254. DOI: 10.7535/hbkd.2016yx03006
Abstract:Because of the existing chromatographic separation phenomenon, ASP flooding changes original nature of the system. Therefore, in laboratory ultra-low interfacial tension ASP system is preferred for sand packs flow experiment to research on the effect of chromatographic separation on ASP system interface tension. The two parameters of "breakthrough time" and "output difference" are used to describe the degree of chromatographic separation, and the produced fluid interfacial tensions at the outlet end at 120 min is measured. The research shows that there exists chromatographic separation between three chemicals of ASP system, with first polymer breakthrough and finally surfactant breakthrough; there is most serious chromatographic separation between surfactant and polymer, while minimum chromatographic separation between alkali and polymer; chromatographic separation makes ASP interfacial tension increase from 10-3 magnitude to 10-2 magnitude, affecting flooding effect of ASP system. Thus, reducing the loss of surfactant in the formation will be the main measure to reduce the degree of chromatographic separation. Using sophorolipid as sacrificial agent to replace part of the surfactant injected into formation before ASP system can effectively reduce the impact of chromatography separation and more effectively improve the ultimate recovery ratio.
2016, 37(3):255-261. DOI: 10.7535/hbkd.2016yx03007
Abstract:In order to more effectively control NO emissions in coal-fired flue gas, the denitration reaction is carried out with simulated industrial boiler flue gas in a fixed bed reactor. The influence of char types, reaction conditions, the composition of flue gas and other factors on the conversion rate of NO are discussed. The result shows that the industrial semi-coke is the most suitable experimental coal in the three coals studied, and the industrial semi-coke particle size of 0.6 ~ 10 mm is relatively suitable; The conversion rate of NO increases gradually with the increase of temperature, and when the reaction temperature is 700 ℃ and the space velocity is 10 000 h-1, the conversion rate of NO can reach 99%; the conversion rate of NO decreases gradually as airspeed increases, but the airspeed change has no effect on the conversion rate of NO at 700 ℃; under anaerobic conditions，the change of NO concentration has no effect on the conversion rate of NO; at the same temperature, NO conversion rate is higher at the presence of oxygen compared with that at anaerobic situation, and the conversion rate of NO is the highest when O2 concentration is 4%; under aerobic conditions, the concentration change of SO2 and CO2 has no effect on the conversion rate of NO.
2016, 37(3):262-267. DOI: 10.7535/hbkd.2016yx03008
Abstract:The image preprocessing is an important part in the field of digital image processing, and it’s also the premise for the image detection of cold steel strip surface defects. The factors including the complicated on-site environment and the distortion of the optical system will cause image degradation, which will directly affects the feature extraction and classification of the images. Aiming at these problems, a method combining the adaptive median filter and homomorphic filter is proposed to preprocess the image. The adaptive median filter is effective for image denoising, and the Gaussian homomorphic filter can steadily remove the nonuniform illumination of images. Finally, the original and preprocessed images and their features are analyzed and compared. The results show that this method can improve the image quality effectively.
2016, 37(3):268-274. DOI: 10.7535/hbkd.2016yx03009
Abstract:A U model based Super-Twisting synchronization control method for chaotic systems is proposed. The chaos control of chaotic systems is prescribed, then, based on the current research status of chaotic systems and some useful research results in nonlinear system design, some new methods for chaos control and synchronization are provided, and the controller is designed to achieve the finite time chaos synchronization. The numerical simulations are carried out for Lorenz system and Chen system, and the result proves the effectiveness of the method.
2016, 37(3):275-282. DOI: 10.7535/hbkd.2016yx03010
Abstract:In the machining process of iron tower, the angle steel needs to be operated through clamping, punching, shearing, etc, and different material produces different sound, so it is advised to use sound signal to detect steel materials Q235 and Q345. Experiment system is constructed by using the sound sensor and signal acquisition system, so the continuous sound signal is acquired, and the sound wave of single punching cycle is exacted for the follow-up judgement. For the sound signal in one cycle, MFCC(Mel Frequency Cepstrum Coefficient) parameters are extracted as characteristic parameters, and the distances between the being measured template and the two standard templates of Q235 and Q345 are computed by the DTW (Dynamic Time Warping) method. As a result, which distance is smaller determines the template. In the experiment, two sets of samples for four kinds of angle steels are acquired, respectively, which proves the validity of the method for steel material detection.
2016, 37(3):283-287. DOI: 10.7535/hbkd.2016yx03011
Abstract:To predict the bearing capacity of plate anchors subjected to combined loads, based on the assumption that there is no separation between the plate and soil, the numerical model of the motion and transformation of the plate anchor subjected to combined loads including the normal force, tangential force and bending moment loads in ABAQUS software is set up. The numerical model is proved by comparing the calculated bearing capacity with that of analytical solution. The numerical model is used to calculate the ultimate bearing capacity of the plate anchor subjected to the combined loads including the normal force, the tangential force and bending moment. The results show that murff model is used to preferably fit the ultimate bearing capacity envelope of plate anchors subjected to combined loads.
2016, 37(3):288-293. DOI: 10.7535/hbkd.2016yx03012
Abstract:In order to study the influence of structure parameters of the reinforcing rib to the mechanical properties of plastic well covers, according to the theory of elasticity, the stress situation of the plastic well cover with reinforcing rib is analyzed with finite element method. The load simulation of the plastic well cover with different reinforcing rib structure parameters is conducted with Abaqus software, and the relationship between the structure parameters of the reinforcing rib and the mechanical properties of the plastic well cover are analyzed. The simulation result shows the stiffness and mechanical properties of the plastic well cover are improved by increasing the height (h) or width (b) of the rib; if h is smaller than 80 mm, the effect of increasing h is extraordinary for improving the stiffness and mechanical properties of the plastic well cover, while the effect of increasing b is not obvious; as h increases, the effect of increasing h is declining, but the effect of increasing b is strengthening relatively; if h is bigger than 160 mm, the effect of increasing h is very small, while the effect of increasing b is higher than the effect of increasing h; the maximum stress of the reinforcing rib is higher than that of the panel, and their deference reduces as the mechanical properties of the plastic cover is improved.
2016, 37(3):294-301. DOI: 10.7535/hbkd.2016yx03013
Abstract:In order to guarantee the running effect of Guodian Shenyang North Wastewater Treatment Plant, based on excitation-emission matrix (EEM) fluorescence spectroscopy, fluorescence regional integration (FRI) and material balance are used to evaluate the dissolved organic matter removal performance of modified A2O process. The results suggest that the albuminoid matters are the dominant components in modified A2O process influent, and there is small amount of fulvic-like materials. The removal efficiencies of the normalized integral volume of region Ⅰ, Ⅱ and Ⅳ are 81.5%, 54.0% and 63.4%, respectively, while the removal performance of normalized integral volume of region Ⅲ and Ⅴ is low, and the removal efficiencies are 30.2%, 27.8%, respectively. The calculation of material balance shows that pre-anoxic and anaerobic zones are mainly used for the material removal in the region Ⅰ and Ⅳ. Anoxic zone is mainly used for material removal in the region Ⅰ. Aerobic zone could remove material in all regions. In addition, normalized integral volume of region Ⅳ and the soluble chemical oxygen demand have nice linear correlation, and the correlation coefficient R2 is 0.991 1. The normalized integral volume of region Ⅳ can better reflect the variation trend of soluble chemical oxygen demand in modified A2O process.
2016, 37(3):302-308. DOI: 10.7535/hbkd.2016yx03014
Abstract:In order to improve the efficiency of anaerobic digestion for biogas production and achieve the resource recovery and decrement of antibiotic bacterial residue, ultrasonic/alkaline pretreatment is used to treat penicillin bacterial residues (PBR), the influence of pH value, ultrasonic sound energy density, moisture content and reaction time on pretreatment effect are investigated, and the biodegradability of PBR is evaluated by biochemical methane potential (BMP) test. The orthogonal experiment result shows that ultrasonic/alkaline pretreatment can enhance the residue cell wall broken effect, and promote intracellular organic matter dissolution. The optimum pretreatment conditions are pH of 10, ultrasonic sound energy density of 20 W/mL, moisture content of 97%, and pretreatment time of 5 min. In this case, the highest COD dissolution rate can reach 84.69%, which is 2.08 times higher than that by the ultrasonic pretreatment only. The BMP test results show that the impact of the pretreatment factors is as follows: moisture content > ultrasonic sound energy density > reaction time > pH value. The optimum pretreatment conditions according to methane productivity are pH of 9, ultrasonic sound energy density of 0.5 W/mL, moisture content of 96%, and reaction time of 30 min. In this case, the methane yield rate can reached 335 mL/g, which is 2.2 times higher than that from the untreated bacteria residue.
2016, 37(3):309-314. DOI: 10.7535/hbkd.2016yx03015
Abstract:In order to improve the operation performance of microbial fuel cells, improved the degradation rate of nitrate and the power output of microbial fuel cell, a typical single chamber air-cathode microbial fuel cell (AC-MFC) is inoculated and operated with urban sewage treatment plant clarifier sludge as inoculum source and sodium nitrate as electron acceptor. It is successfully started by synthetic wastewater containing a phosphate buffered nutrient solution (PBS, 50 mmol/L) and sodium acetate (1 g/L). After successful starting, the four factors of carbon source, C/N, nitrate concentration and temperature are considered to optimize the operation performance of MFC. The test result shows that the operation performance of MFC is best under the conditions of anhydrous sodium acetate as carbon source, C/N of 5∶1, 200 mg/L nitrate concentration and at 30 ℃, and the degradation rate of nitrate reaches more than 90% and the voltage of MFC is 0.462 V. After 6 cycles of operation, the voltage and power density of MFC reaches 0.62 V and 4.53 W /m2. AC impedance analysis indicates that the MFC resistance is 130 Ω. Scanning electron microscopy of electrode surface illustrates that the number of microbial species are significantly increased. The results indicate that MFC can be an effective technology for nitrate contained wastewater treatment and energy production.