• Volume 38,Issue 6,2017 Table of Contents
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    • >Special Column: National Young Scholar/Local Science Foundation
    • Research process of nondestructive testing pitting corrosion in metal material

      2017, 38(6):507-514. DOI: 10.7535/hbkd.2017yx06001

      Abstract (1976) HTML (0) PDF 988.52 K (3461) Comment (0) Favorites

      Abstract:Pitting corrosion directly affects the usability and service life of metal material, so the effective nondestructive testing and evaluation on pitting corrosion is of great significance for fatigue life prediction because of data supporting. The features of pitting corrosion are elaborated, and the relation between the pitting corrosion parameters and fatigue performance is pointed out. Through introducing the fundamental principles of pitting corrosion including mainly magnetic flux leakage inspection, pulsed eddy current and guided waves, the research status of nondestructive testing technology for pitting corrosion is summarized, and the key steps of nondestructive testing technologies are compared and analyzed from the theoretical model, signal processing to industrial applications. Based on the analysis of the signal processing specificity of different nondestructive testing technologies in detecting pitting corrosion, the visualization combined with image processing and signal analysis are indicated as the critical problems of accurate extraction of pitting defect information and quantitative characterization for pitting corrosion. The study on non-contact nondestructive testing technologies is important for improving the detection precision and its application in industries.

    • Research progress of the three-dimensional(3D) multicellular structure formation via self-assembly of cells toward tissue engineering

      2017, 38(6):515-521. DOI: 10.7535/hbkd.2017yx06002

      Abstract (1593) HTML (0) PDF 2.91 M (2855) Comment (0) Favorites

      Abstract:Multicellular structures are organisms consisting of cell populations, and constructing multicellular structure is of great importance for the development of tissue engineering and regenerative medicine. The use of self-organization processes in three-dimensional (3D) culture is receiving increased attention for bio-manufacturing and regenerating injured tissue. This review covers the research work on the fundamental and key techniques regarding 3D cellular self-assembly. It includes the 3D culture of cells inside bio- compatible hydrogels, controllable formation of 3D multicellular structure, and the associated Turing reaction-diffusion mechanism. In order to further study the mechanism of 3D self-assembly of cells and find a reliable way to regulate this self-organization in 3D extracellular matrix with spatial gradients of the concentrations of exogenous and cell-secreted factors, this review at last proposes to study the 3D models of cellular self-assembling inside structurally graded hydrogel, so that the development of rational regulation technology for 3D multicellular structure and tissue bud could be facilitated.

    • Mechanic properties analysis of quasi-square honeycomb sandwich structure′s core

      2017, 38(6):522-529. DOI: 10.7535/hbkd.2017yx06003

      Abstract (1738) HTML (0) PDF 1.67 M (4111) Comment (0) Favorites

      Abstract:In order to illustrate the relationship between the quasi-square-honeycomb structure and the hexagonal honeycomb structure, after decomposing the quasi-square honeycomb sandwich structure into unique T-shaped cell, the equivalent elastic constants equations of T-shaped cell model are derived respectively by applying Euler beam theory and energy method. At the same time, the quasi-square honeycomb's characteristic structure parameters are substituted into the equivalent elastic constants equations which are derived by the classical method of a hexagonal honeycomb core, and the same results are obtained as that of the preceding both methods. It is proved that the quasi-square-honeycomb structure is an evolution of hexagonal honeycomb. The limitations and application scope of the two classical honeycomb formulas are pointed out. The research of the structural characteristics of the square-shaped honeycomb shows that the classical cellular theoretical formula are singular and inaccurate when the feature angle values equal to zero or near zero. This study has important reference value for the subsequent research and improvement of the theories about cellular structure mechanical properties.

    • Characteristics and mechanism of NOx emission of hydrogen fueled internal combustion engine

      2017, 38(6):530-535. DOI: 10.7535/hbkd.2017yx06004

      Abstract (1813) HTML (0) PDF 1.91 M (3068) Comment (0) Favorites

      Abstract:In order to deeply study the NOx formation mechanism of hydrogen fueled internal combustion engine (HICE), a hydrogen fueled internal combustion engine CFD simulation model including three-dimensional gridding coupling detailed chemical reaction mechanism is built based on CONVERGE software, and the combustion and emission characteristics of hydrogen fueled internal combustion engine under different loads are researched. The simulation result is consistent with the experimental data. The simulation results show that the increasing concentration of hydrogen is beneficial to improving the efficiency of hydrogen fuel internal combustion engine. The large amount of NO generates in the rapid combustion period, the total amount of NO decreases constantly after the rapid combustion period, and the total amount of NO tends to be stable when the average temperature is below 2 200 K. NO is generated mainly through three paths including thermo NO, NNH and N2O, and the thermo NO path contributes a large proportion of total NO emissions, whose contribution ratio increases with the increase of fuel-air equivalence ratio. NNH and N2O contribute about 25% of total NO emissions at lower concentrations, while when fuel-air equivalence ratio is 1.0, the sum of the contributions of these two paths to NO generation is negative. The contribution ratios for NO generation of three paths under different loads are obtained using chemical reaction kinetics method, which can reveal the NOx generation mechanism of hydrogen fuel internal combustion engine and establish the theoretical foundation for subsequent study.

    • >Mathematics
    • Stabilization analysis of Euler-Bernoulli beam equation with locally distributed disturbance

      2017, 38(6):536-541. DOI: 10.7535/hbkd.2017yx06005

      Abstract (1608) HTML (0) PDF 915.37 K (2137) Comment (0) Favorites

      Abstract:In order to enrich the system stability theory of the control theories, taking Euler-Bernoulli beam equation as the research subject, the stability of Euler-Bernoulli beam equation with locally distributed disturbance is studied. A feedback controller based on output is designed to reduce the effects of the disturbances. The well-posedness of the nonlinear closed-loop system is investigated by the theory of maximal monotone operator, namely the existence and uniqueness of solutions for the closed-loop system. An appropriate state space is established, an appropriate inner product is defined, and a non-linear operator satisfying this state space is defined. Then, the system is transformed into the form of evolution equation. Based on this, the existence and uniqueness of solutions for the closed-loop system are proved. The asymptotic stability of the system is studied by constructing an appropriate Lyapunov function, which proves the asymptotic stability of the closed-loop system. The result shows that designing proper anti-interference controller is the foundation of investigating the system stability, and the research of the stability of Euler-bernoulli beam equation with locally distributed disturbance can prove the asymptotic stability of the system. This method can be extended to study the other equations such as wave equation, Timoshenko beam equation, Schrodinger equation, etc.

    • American option pricing with stochastic volatility processes

      2017, 38(6):542-547. DOI: 10.7535/hbkd.2017yx06006

      Abstract (1707) HTML (0) PDF 1.13 M (3732) Comment (0) Favorites

      Abstract:In order to solve the problem of option pricing more perfectly, the option pricing problem with Heston stochastic volatility model is considered. The optimal implementation boundary of American option and the conditions for its early execution are analyzed and discussed. In view of the fact that there is no analytical American option pricing formula, through the space discretization parameters, the stochastic partial differential equation satisfied by American options with Heston stochastic volatility is transformed into the corresponding differential equations, and then using high order compact finite difference method, numerical solutions are obtained for the option price. The numerical experiments are carried out to verify the theoretical results and simulation. The two kinds of optimal exercise boundaries under the conditions of the constant volatility and the stochastic volatility are compared, and the results show that the optimal exercise boundary also has stochastic volatility. Under the setting of parameters, the behavior and the nature of volatility are analyzed, the volatility curve is simulated, the calculation results of high order compact difference method are compared, and the numerical option solution is obtained, so that the method is verified. The research result provides reference for solving the problems of option pricing under stochastic volatility such as multiple underlying asset option pricing and barrier option pricing.

    • >Chemistry and Chemical Industry
    • Study on extraction of cellulose from corn cobs by deep eutectic solvents

      2017, 38(6):548-554. DOI: 10.7535/hbkd.2017yx06007

      Abstract (2105) HTML (0) PDF 1.60 M (3178) Comment (0) Favorites

      Abstract:In order to explore a new method for the separation and extraction of cellulose, cellulose is extracted from waste biomass corn cobs by deep eutectic solvent(DES), in which 1,4-butanediol (BDO) and choline chloride (ChCl) are used as the donor and the acceptor of hydrogen bonds, respectively. The influence of the molar ration of ChCl to BDO, the treatment temperature, the interaction time and liquid-solid ratio to fiber material yield and cellulose content under ordinary pressure is investigated through experiment. The structures of raw materials and the products are characterized by using infrared spectroscopy (FT-IR), thermogravimetric (TG/DTG), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The result shows that the fiber material yield and cellulose content are 44.6% and 77.8%, respectively under the optimum conditions which are ChCl-BDO molar ration of 1∶3, treatment temperature of 180 ℃, reaction time of 4 h and liquid-solid ration of 20∶1(g∶g), and under the condition, the removal rate of lignin and hemicellulose are 95% and 75%, respectively, with only losing a little cellulose. The FT-IR, TG/DTG, XRD and SEM results show that the lignin and hemicellulose in the corn cobs are greatly removed after DES treatment. The fiber material internal is more loose and the structure of the cellulose is barely damaged. The result shows that DES has a good prospect in the field of cellulose separation and extraction.

    • Computational study of the influence of second receptor unit on theperformance of triphenylamine sensitized dyes

      2017, 38(6):555-563. DOI: 10.7535/hbkd.2017yx06008

      Abstract (1804) HTML (0) PDF 3.83 M (1997) Comment (0) Favorites

      Abstract:In order to enhance the performance of triphenylamine sensitized dyes, six kinds of new D-A′-π-A dyes are designed by introducing the different second receptor unit A′ based on the dye B1 with D-π-A construction. Then the geometries optimization, charge distribution and energy level of the dyes are investigated by using density functional theory in the computational chemistry. The results show that all of the six designed dyes have stable structure. Due to the introduction of the second receptor unit, the band gaps are narrowed, and the absorption spectrum is broadened, causing red shit in the new dyes. Comparing with the B1(396.6nm), the red shits of the six kinds of dyes are B1-PDP(418.4 nm)

    • >Mechanical, Electronics and Information Science
    • Fine-grained vehicle type recognition based on deep convolution neural networks

      2017, 38(6):564-569. DOI: 10.7535/hbkd.2017yx06009

      Abstract (2257) HTML (0) PDF 1.72 M (4690) Comment (0) Favorites

      Abstract:Public security and traffic department put forward higher requirements for real-time performance and accuracy of vehicle type recognition in complex traffic scenes. Aiming at the problems of great plice forces occupation, low retrieval efficiency, and lacking of intelligence for dealing with false license, fake plate vehicles and vehicles without plates, this paper proposes a vehicle type fine-grained recognition method based GoogleNet deep convolution neural networks. The filter size and numbers of convolution neural network are designed, the activation function and vehicle type classifier are optimally selected, and a new network framework is constructed for vehicle type fine-grained recognition. The experimental results show that the proposed method has 97% accuracy for vehicle type fine-grained recognition and has greater improvement than the original GoogleNet model. Moreover, the new model effectively reduces the number of training parameters, and saves computer memory. Fine-grained vehicle type recognition can be used in intelligent traffic management area, and has important theoretical research value and practical significance.

    • A resonant multi-channel sharing current LED driver based on variable inductor

      2017, 38(6):570-577. DOI: 10.7535/hbkd.2017yx06010

      Abstract (1655) HTML (0) PDF 2.88 M (2201) Comment (0) Favorites

      Abstract:In order to solve the problems of the traditional LED driver adopting the frequency control with high EMI, pulse width modulation (PWM) with the complex control circuit,and the LLCC, LCLC resonant topology realizing constant current output system with the large volume, high cost and low power density, a resonant multi-channel sharing current LED driver based on variable inductor is presented. The variable inductor(VI) is used to replace the fixed inductance, which changes the resonant frequency for achieving dimming and controlling. Meanwhile, the resonant is introduced to realize the high conversion efficiency in ZVS(zero voltage switching) of all devices. The current sharing capacitor is used in each channel to simplify the structure of the circuit. Based on the theoretical analysis and simulation, an 11 W laboratory prototype is built to achieve the 4-channel LED driver. The research results show the multiple LED driver improves the characteristic of the current-sharing and frequency conversion dimming, as well as the power density and the service life of LED drivers, suiting for application in surgery dimming and home lighting.

    • Application of improved PSO-RBF neural network in the synthetic ammonia decarbonization

      2017, 38(6):578-584. DOI: 10.7535/hbkd.2017yx06011

      Abstract (1473) HTML (0) PDF 1.32 M (2229) Comment (0) Favorites

      Abstract:The synthetic ammonia decarbonization is a typical complex industrial process, which has the characteristics of time variation, nonlinearity and uncertainty, and the on-line control model is difficult to be established. An improved PSO-RBF neural network control algorithm is proposed to solve the problems of low precision and poor robustness in the complex process of the synthetic ammonia decarbonization. The particle swarm optimization algorithm and RBF neural network are combined. The improved particle swarm algorithm is used to optimize the RBF neural network's hidden layer primary function center, width and the output layer's connection value to construct the RBF neural network model optimized by the improved PSO algorithm. The improved PSO-RBF neural network control model is applied to the key carbonization process and compared with the traditional fuzzy neural network. The simulation results show that the improved PSO-RBF neural network control method used in the synthetic ammonia decarbonization process has higher control accuracy and system robustness, which provides an effective way to solve the modeling and optimization control of a complex industrial process.

    • >Material Science
    • Analysis of carburizing steel with lath bainite in matrix by magnetic method

      2017, 38(6):585-589. DOI: 10.7535/hbkd.2017yx06012

      Abstract (1750) HTML (0) PDF 2.15 M (2659) Comment (0) Favorites

      Abstract:The cryogenic treatment is used to reduce the large amount of retained austenite in the steel infiltration layer which affects the hardness. The vibrating sample magnetometer (VSM) and direct reading spectroscopy are combined to compare and analyze the organization structure status of the test carburizing steel after air-cooling and low temperature tempering (T) at 453 K × 1 h, or after cryogenic treatment at 113 K × 30 min and low temperature tempering (T) at 453 K × 1 h. The cryopreservation effect of the 1 203 K × 9 h carburizing air-cooled bainitic steel is carried out. The results show that both the effective hardening layer depths are about 1.35 mm. The retained austenite mass fractions of T and CT in the effective hardened layer are approximately 29.8% and 12.6%, respectively, and the highest hardnesses of the effective hardened layer of T and CT are 679 HV and 821 HV, respectively. The matrix structure is lath bainite, and the retained austenite mass fractions in the matrix are approximately 7.4% for T and 6.9% for CT, respectively, and both the hardnesses of the matrixes are approximately 430 HV. After the cryogenic treatment, the austenite content in the infiltration layer is effectively reduced, so that the maximum hardness of the hardened layer increases by 20% or more. It can be widely used because of the decreased material cost and remarkable economical benefit.

    • >约稿:数据分析与计算专栏
    • Investigation on the pollution of road rainwater runoff in Shijiazhuang City

      2017, 38(6):591-599. DOI: 10.7535/hbkd.2017yx06013

      Abstract (1925) HTML (0) PDF 1.60 M (2225) Comment (0) Favorites

      Abstract:To protect groundwater and urban ecological environment, much more sponge cities have been built in China. The sponge road is an important part of a sponge city. In recent years, Shijiazhuang Municipal Design Institute proposes a new sponge road structure, namely planting soil and crushed stone green belt, and it has been extensively used in Shijiazhuang City. In the design of the road structure, it is a key issue whether the infiltration rainwater quality pollutes the groundwater. Therefore, it is necessary to investigate the pollution of road rainwater runoff in Shijiazhuang City for the design of sponge road and the construction of sponge city. To obtain the characteristics of rainwater runoff pollution in Shijiazhuang City, four investigation points are chosen at the intersection of the Nanerhuan Road and Yuxiang Street, the east gate of Hebei University of Science and Technology, the site under the Xierhuan Road and Zhongshan Road overpass, and the catch-basin along the roadside in Shijiazhuang City. The investigating points are located in the main road of Shijiazhuang urban area, which covers Shijiazhuang City, and can represent the pollution characteristics of road runoff in Shijiazhuang City. Six rainfalls are collected from March to June in 2017. The rainfall on 3, May is viewed as typical middle and light one which is studied in this paper. The concentration of COD, TP, TN, NH3-N and SS in road runoff is tested by potassium dichromate method, ammonium molybdate spectrophotometry, potassium persulfate digestion-UV spectrophotometry and Nessler’s reagent spectrophotometry and filter paper filtration, respectively. The concentrations of Zn ions and Pb ions are tested by inductively coupled plasma method. According to the test results, the concentration evolutions of COD, TP, TN, NH3-N, SS, Zn and Pb ion in runoff during rainfall are studied. The results show that the contaminant concentration approximately decreases during the rainfall, and then maintain stable for 90 min. The relation between contaminant concentration and rainfall time follows the form of negative exponential function. Based on the investigation results, the design values of pollutant concentrations at the initial runoff and the long runoff of rainwater in Shijiazhuang are proposed by time-weighted average method and rainfall-weighted average method, respectively. The recommended values by former method for initial runoff in Shijiazhuang are as follows: TN, NH3-N, TP, SS and COD are 14.49 mg/L, 10.93 mg/L, 0.45 mg/L, 651.00 mg/L and 437.73 mg/L. The recommended values by former method for long runoff of water in Shijiazhuang are as follows: in 90 min TN, NH3-N, TP, SS and COD are 8.05 mg/L, 5.60 mg/L, 0.59 mg/L, 559.22 mg/L, and 237.96 mg/L, respectively. After 90 min they are 5.13 mg/L, 4.11 mg/L, 0.58 mg/L, 422.67 mg/L and 97.35 mg/L. The recommended values by later method for initial runoff in Shijiazhuang are as follows: TN, NH3-N, TP, SS and COD are 14.40 mg/L, 10.86 mg/L, 0.50 mg/L, 684.10 mg/L and 440.08 mg/L. The recommended values by later method for long runoff of water in Shijiazhuang are as follows: in 90 min TN, NH3-N, TP, SS and COD are 12.46 mg/L, 9.19 mg/L, 0.52 mg/L, 642.80 mg/L and 363.92 mg/L. After 90 min they are 5.13 mg/L, 4.11 mg/L, 0.58 mg/L, 423.30 mg/L and 97.35 mg/L. Overall the proposed concentration values by the rainfall weighted average method are slightly larger than those by the time weighted average method. For hardly degradable Zn and Pb ions in the soil, the 30 min time-weighted concentration at the initial runoff and the long runoff of rainwater is proposed as the design values of runoff rainwater. The recommended design values of Zn and Pb ions are 0.67 mg/L and 0.11 mg/L, respectively.

    • Study on the factors and mechanism of B2C online shopping logistics service based on consumer reviews mining

      2017, 38(6):600-608. DOI: 10.7535/hbkd.2017yx06014

      Abstract (2595) HTML (0) PDF 1.49 M (4564) Comment (0) Favorites

      Abstract:With the rapid development of e-commerce and the change of consumption patterns, more and more consumers are beginning to choose online shopping. Logistics service has become one of the important factors that affects consumer satisfaction of online shopping and restricts the development of e-commerce enterprises. Therefore, it explores the factors influencing the online shopping logistics service and the corresponding relationship between them, and designs corresponding optimization solutions to provide better services to customers, further improve customer satisfaction, establish a good image for the enterprise and improve the efficiency of enterprises. In order to explore the types and the mechanism of consumer online shopping logistics services, from the perspective of online shopping consumers, the evaluation information of online shoppers on the platform is taken as the object of study, using the octopus data collection tool from Tmall to grab a large number of comments, conducting the in-depth analysis and mining using grounded theory research method, and further extracting the main categories and types of logistics service factors through open coding, spindle coding and selective coding. The composition of online shopping logistics service factors is divided into 7 main categories, the main category relationship structure is further mined, and the factors influencing the quality of online shopping logistics service are summarized as four main types of distribution quality, perception experience, after-sales service quality and reliability. Based on the typical relational structure of the main category, the core category of "key influencing factors of online shopping logistics service satisfaction" is finally determined, and the role model of logistics service quality is analyzed. Using the semantic network analysis and theoretical saturation test to verify the types of logistics service quality factors and their mechanism of action, the semantic network analysis using the ROST Content Mining knowledge processing and content mining software to conduct the whole network analysis, and using word frequency analysis and keyword co-occurrence analysis, the results are verified; and the research results are further verified by theoretical saturation test using the original data method and reliability assessment method. The results show that: perceived experience is the direct driving factor of online shopping logistics services, which determines whether the customer conducts online shopping. The quality of after-sales service and reliability indirectly drives consumers' online shopping behavior by influencing perception experience, which is the indirect factor of online shopping logistics service. Delivery quality can not only directly affect the quality of online shopping logistics service but also indirectly affect the online shopping logistics service quality through the perception experience. Obviously, it is necessary to explore the influencing factors of online shopping logistics service. By improving the logistics service in the above aspects, it not only can improve customer satisfaction, acquire and maintain a stable customer base in order to maintain the competitive advantage of enterprises, but also can be used as an important basis for e-commerce enterprise to improve its logistics system, and explore the weak link of the logistics to enable enterprises to get better development. The results of this study are of great significance for B2C e-commerce enterprises to improve the quality of logistics service and improve the competitiveness of enterprises.

Editor in chief:朱立光

Inauguration:

International standard number:ISSN 1008-1542

Unified domestic issue:CN 13-1225/TS

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