2007 volumne 28 Issue 04

Zheng Juanrong; Liu Lina
Abstract: The effects of different curing temperatures (10 °C, 20 °C, 30 °C, 60 °C, 90 °C) on the coagulation hardening properties of metakaolin base polymers and the NH+4 exchange capacity of reactants were studied. The results showed that under moisturizing conditions, the setting time of metakaolin base polymer was shortened and the development rate of compressive strength slowed down with the increase of curing temperature. Under the condition of room temperature below 20 °C and moisturizing, the metakaolin base polymer did not condense for 24 h, and the incorporation of slag powder could promote its coagulation. However, with the increase of slag powder, the NH+4 exchange capacity of the reactants decreased.

LIU Lixin; Wang Xiaolin; YU Qiubo; etc
Abstract: Through the fatigue test of two prestressed concrete beams with pretensioned linear reinforcement and one prestressed concrete beam with bonded part after tension, the flat-section assumption under fatigue load is verified, the variation law of deflection with the increase of fatigue cycle times is analyzed, and the calculation method and calculation formula of deflection of some prestressed concrete beams under fatigue load are discussed. The results show that the results calculated according to the formula proposed in this paper are in good agreement with the experimental results.
GUO Yuancheng; WANG Kun; Zhou Tonghe
Abstract:

Composite pile wall support structure is a new type of composite support structure system composed of cement-soil pile wall and vertical pile through reinforced concrete roof plate. Based on a comprehensive summary of the types of composite pile wall support architecture and its calculation model, combined with field experimental research and numerical simulation, this paper proposes a design and calculation method based on the overall calculation mode of single-row small pile composite cement-soil pile wall support system, which provides a certain technical reference for the design and construction of the same type of foundation pit engineering.

LIU Lixin; An Hongfei; YU Qiubo; etc
Abstract:

Through the construction monitoring of the 35 m folded line first tension beam, the influence of the deformation of the tension beam and the reaction beam, the frictional resistance of the steering gear on the prestress loss, and the prestress loss under other conditions were analyzed. The results show that the calculation of prestress loss of prestressed box girder is more accurate than that of post-tensioned prestress method, which avoids engineering diseases caused by unreliable prestress value, and the total prestress loss value of prestressed linear box girder is smaller than that of post-tensioned method, which ensures the tensile stress. The analysis shows that the stress loss caused by shrinkage and creep of concrete in the tensile area and compression zone has the largest proportion of the total prestress loss of the pre-tensioned linear box girder, so it is an effective measure to control the total prestress loss of the pre-tensioned linear box girder by reducing the shrinkage and creep of concrete.
Zhan Yuzhong; ZHU Xiaoli; LI Lingling; etc
Abstract:

The adsorption and fluorine removal performance of silica gel-supported zirconia was studied by static adsorption method, and the effects of solution pH, adsorbent dosage, initial concentration, and adsorption time at different temperatures and initial concentrations on adsorption were investigated. The results show that the pH of the solution has a great influence on adsorption, and the pH value of the maximum adsorption is 3~4.The adsorption rate can be described by the quasi-secondary kinetic equation, and the adsorption equilibrium can be reached within 200 min. The adsorption isotherm conforms to the Langmuir equation, and the calculated adsorption equilibrium constant is 1.31 L/mg, and the saturated adsorption capacity is 7.46 mg/g, indicating that the adsorbent has a large affinity for fluorine and a high saturation adsorption capacity.
CHEN Yiliang; SHI Xiaohong; Guo Shiling; etc
Abstract:

In order to optimize the application of L zeolite in petroleum catalytic cracking, L zeolite was modified by different ion exchange methods. The effects of different ion exchange methods on reducing the potassium content of L zeolite and the changes of L zeolic acid properties after modification were investigated. The results showed that the combination of ion exchange and water vapor treatment was more effective in reducing the potassium content of L zeolite, and the potassium oxide content of L zeolite samples after tertiary ion exchange and tertiary water vapor treatment could be reduced to 0.82%. The results of NH3–TPD heating and desorption experiments showed that the strength of the acid center on the modified L zeolite surface increased, the acid strength distribution became wider, and the total acid content decreased. From the infrared pyridine adsorption spectra, it can be seen that B acid center and L acid center appeared on the surface of L zeolite after modification.

GUO Jianguo; JIAO Yu; HE Suqin; etc
Abstract:

The end group structure of dialkyl polyether was characterized by infrared spectroscopy and nuclear magnetic resonance. Through the test of the physical and chemical properties (heat resistance, viscosity, surface tension) of the dialkyl polyether, the influence of the structure of the dialkyl polyether on its physical and chemical properties was obtained. It was found that with the increase of the termination rate of dialkyl polyether, the heat resistance of polyether became significantly better, the viscosity decreased, the stability of aqueous solution improved, and it had better surface activity.

ZHOU Yan; Li Weimin; Yuan Liming
Abstract:

Cellulose tris(3,5-dimethylphenylcarbamate) was synthesized and used as a stationary phase by gas chromatography to prepare chiral capillary columns to investigate its polarity, column efficiency and chiral selectivity. The results showed that the stationary phase was moderately polar, with a theoretical plate count of 1 895 m-1 and a capacity factor of 1.52.The column successfully isolated 25 of the 20 randomly selected racemic compounds (including alcohols, ethers, amines, esters, aldehydes, ketones, amino acids), including (±)-Dihydrocarvylacetate, (±)-Roseoxide, (±)-N-Benzyl-1-phenylethylamine, (±)- Fenchone, DL-Leucine and DL-Isoleucine had good separation effects, which confirmed that the column had good chiral separation performance and could be used in gas chromatography.

ZHANG Fengfeng; SUN Lining; Du Zhijiang; etc
Abstract:

In the virtual simulation study of human legs, it is an effective method to establish a finite element model and analyze the biomechanical characteristics. However, due to the large amount of data, long solution time, and difficulty in integrating with existing systems, the finite element model is not suitable for real-time surgical training and surgical rehearsal. In order to improve the ability of the virtual surgical simulation system to carry out actual operations, the author proposes to replace the finite element model with the BP neural network model to achieve real-time biomechanical response. Combined with the existing medical robot-assisted osteopathic virtual reality simulation surgery system, a system experimental platform was constructed. Experimental results show that the BP neural network model of human legs can fully meet the real-time requirements required for surgical simulation.
FAN Wenbing; CAO Xiaoguang; Chen Yan
Abstract: Firstly, the concept of RFID middleware is introduced, and then the packaging format of the data processed by the communication component is introduced: that is, the communication protocol format of a series of high-frequency readers of an enterprise. On this basis, the software design of five interface components, including the underlying data communication interface component, the device network interface component, the device parameter interface component, the label read and write operation interface component, and the database interface component, is established, and finally the design of RFID middleware communication component is realized, which provides a foundation for third-party enterprise software applications.

WANG Xudong; Chen Genyong
Abstract:

A method for evaluating the reliability of complex distribution network using interval algorithm is proposed. In order to simplify the network, according to the characteristics of complex distribution network, the network equivalent method is used to obtain a simple radial network by carrying out upward and downward equivalence processes. The algorithm analyzes and processes the original reliability parameters of the components of the distribution system, obtains the original interval parameters of the reliability of each component, and obtains the reliability interval index of the load point and the system and the economic loss interval value of the power outage. The reliability evaluation of RBTS-BUS2 system is carried out by applying the algorithm, and the results show that the algorithm is flexible, efficient and has engineering practical value.

TIAN Zhizhi; Wufang; Xiong Wei
Abstract:

Combined with the development practice of highway geographic information system, the data characteristics of highway geographic information system are analyzed and discussed, and the ways and methods of multi-source data, linear reference system and dynamic segmentation data model structure design and technical implementation of highway geographic information are proposed.

Ren Hui; Zhou Zhenhong
Abstract:

In Fortran’s hybrid programming with C/C++, data is mainly passed through routine parameters, which complicates the design of the called routine interface, and sometimes cannot directly utilize existing algorithm routines. An alternative way to pass data is proposed, that is, to share common external data between the two languages, including global variables and common areas/structs. The example results show that it is entirely feasible for Fortran to share common external data with C/C++ with appropriate measures, thus providing a new way to transfer data between the two languages.
ZHAO Feng; Pi Suping; Zhou Zhenhong
Abstract:

AutoCAD provides a programming model that enables efficient drafting in batch processing and powerful graphics capabilities for applications. Programmatically controlled AutoCAD drawings, usually VB/VBA drawing using its object model’s automated interface, its program execution performance is relatively low. The method of Delphi drawing through the dual interface of the object model provided by AutoCAD is proposed, and the specific implementation of typical examples is given. The example results show that the Delphi drawing method not only provides programming flexibility, but also makes the application have high execution performance, which provides a new way for programming and controlling AutoCAD drawing.
Ge Guangtao; Sang Enfang; LIU Zhuofu; etc
Abstract: A method for extracting geomorphological and texture features of hydroacoustic images based on The Bidimensional Empirical Mode Decomposition (BEMD) is proposed. In order to solve the problem of interference from the presence of acoustic shadow area on the feature extraction of underwater acoustic images, the two-dimensional modal decomposition of the underwater acoustic images is carried out first, and the Canny edge detector is used to extract the features of mode 1 or the superposition of several modes. Experimental results show that this method enhances the feature information of targets in the acoustic shadow area and weakens the shadow edge in the acoustic shadow area, which is a practical new method for feature extraction of underwater acoustic images.

Deng Yuehong; Nie Shuangshuang
Abstract:

By analyzing the shortcomings of ultrasonic ranging by the traditional threshold detection method, an underwater ultrasonic ranging method based on wavelet transform is proposed. Using digital signal processing technology, a digital band-pass filter based on Hamming’s window function is designed to digitally filter the sampled signal and construct a Gaussian wavelet base. An ultrasonic underwater ranging system that convolves the sampled signal with the wavelet base for wavelet transformation and accurately captures the arrival time of the echo signal is introduced. The traditional threshold detection method and the ultrasonic ranging method based on wavelet transform were used in the laboratory pool, and the measurement data were compared, which verified that the underwater ultrasonic ranging based on wavelet transform could achieve higher measurement accuracy and was better than the traditional threshold detection method.
Bu Yingyong; ZHANG Chao; Nie Shuangshuang
Abstract:

A feature extraction method for underwater target echoes is proposed. Based on the discrete wavelet transform, this method can classify the underwater substrate based on the scattering components in the echo signal, extract the underwater echo signal wake envelope feature as the identification feature vector, constitute the feature space based on the wake envelope feature, and then use the best identification vector method to compress the feature space, and finally use the minimum distance classifier to classify the target echo. The measured data show that the envelope feature obtained by this method is a robust and effective feature, which can obtain a high correct recognition rate.

ZENG Tao; Zhao Shengkai
Abstract:

Aiming at a class of nonlinear systems and strict dissipation requirements with norm bounded time-varying parameter uncertainty represented by T-S fuzzy model, a robust dissipative fault-tolerant controller design method with stable and strictly dissipated system during actuator failure is proposed. Applying the parallel distributed control and linear matrix inequality methods, the sufficient conditions for the existence of the fault-tolerant controller in the system dissipated in the event of actuator failure are obtained, and the closed-loop system is robust to the allowable parameter uncertainty. The convex optimization problem of linear matrix inequality constraint is further established and solved, and the design method of fuzzy fault-tolerant controller with stable and strict dissipation system is given. The simulation results show the feasibility and effectiveness of the proposed method.

DONG Zhonghong; Lv Pengmin
Abstract:

The dynamic response of four typical asphalt pavement structures, including thickened semi-rigid base structure, improved semi-rigid base structure, flip-mounted pavement structure and full-thickness pavement structure, under standard load conditions and overload 4% working conditions was analyzed by using the dynamic model of viscoelastic layered system under moving load, and the differences between various pavement structures were studied. The results show that the horizontal shear strain at the bottom of the surface layer has the most serious impact on the service life of the pavement structure.

Li Zuzhong; Chen Jiaofa; Hua Min
Abstract:

The three-dimensional finite element method was used to analyze the influence of the thickness change of Sampave stress absorbing layer on the load stress and temperature stress distribution of asphalt plus pavement structure, and it was found that Sampave stress absorbing layer can greatly reduce the load stress and temperature stress at the bottom of the pavement, which has a particularly obvious effect on the latter, improves the stress state of the entire asphalt surface structure, reduces the stress concentration degree of the bottom of the pavement, delays the formation of reflective cracks in the paving layer, and shows its unique role in anti-reflective cracks. The calculation results show that the stress absorbing layer should not be too thick, and the recommended layer thickness is 2.5±0.5 cm.
XUE Lianxu.
Abstract:

Using the mechanical model of elastic layered system, the tensile stress of the road surface caused by the existence of small structures was analyzed in detail by finite element method and model test method, and its structural properties were studied. The results show that the tensile stress of the road surface caused by the existence of the structure is greatly affected by the top fill height and the thickness of the base layer of the structure, and the backfill compaction on both sides of the structure is more difficult, which is the main cause of disease in the pavement containing the structure.

Qi Lin; ZHANG Zhengqi; Yang Huijun
Abstract:

The low-temperature performance of asphalt mixture under fresh, short-term aging and long-term aging was compared by splitting test method. The test shows that the low-temperature performance of the unaged asphalt mixture cannot reflect and predict the performance after aging, and the short-term aging test is more sensitive than the long-term aging test when evaluating the low-temperature performance of asphalt mixture, which indicates that it is necessary to fully consider the influence of aging factors in the low-temperature performance test evaluation process of asphalt mixture.
Geng Limin; Bian Yaozhang; ZHANG Chunhua; etc
Abstract:

Biodiesel is a clean, renewable alternative fuel. The performance comparison test between biodiesel and 0# diesel was carried out on a four-cylinder supercharged direct injection diesel engine. The dynamics, economy and emission characteristics of biodiesel and 0# diesel were determined at different speeds and loads. The test results show that compared with 0# diesel fuel, the engine power is improved, the effective energy consumption rate is reduced, HC and soot emissions are greatly reduced, NOX emissions are increased, and CO emissions are increased at medium and low speeds.
Xue Xiaogang; ZHANG Zhengqi; Wang Binggang; etc
Abstract: In order to further apply the volume parameters of asphalt mixture in design and construction quality control, the volume parameters are divided into direct parameters and indirect parameters. By mathematically deriving and deforming the intrinsic relationship between the volume parameters, the complex nonlinear relationship between the volume parameters commonly used in the design of asphalt mixture and the asphalt content is transformed into a simple linear relationship between the volume parameters, which is suitable for the design and evaluation of different asphalt mixtures. On this basis, the practical application of the general diagram of volume parameters is studied. Theoretical analysis and practical application results show that it can explain the relationship between compaction mechanism and indirect parameters from the perspective of volume composition, so as to guide the design and construction control of asphalt mixture, which is worth popularizing.

Shen Jianjun; LIU Benxue; Zhang Zhifeng
Abstract:

According to the motion characteristics of anti-drag braking of hydraulically driven vehicles, the influence of hydraulic pump displacement on the downhill braking performance of hydraulically driven vehicles is analyzed, and the principle of reasonably exerting the downhill anti-drag braking ability of hydraulic system and engine is proposed, and experimental verification is carried out. The results show that the size of the displacement of the hydraulic pump directly affects the braking performance and volumetric efficiency of the hydraulic system, and also determines the size of the engine anti-drag braking ability, the braking energy distribution relationship between the hydraulic system and the engine, and affects the change of motor speed.

SUN Lijun; CHEN Long; ZHAO Jingbo; etc
Abstract:

In order to study the influence of power assist characteristics on the steering performance of automobiles, the dynamic model of electric power steering system with corner input was established, and the power assist characteristic curve of EPS was selected. Through simulation, the correctness of the established model is verified. Finally, the self-developed electric power steering controller is used to carry out the real vehicle test, and the test results show that the designed controller can meet the steering performance index well.

Ma Xiaoxia; Shudandane; Huang Yugui
Abstract:

In view of the problems of linearization, complex solution and poor accuracy in the parameter rate determination of the Mastingen flood evolution model, a new method for parameterization of the Mastingen model based on the Particle Swarm Optimization (PSO) algorithm is proposed, and it is applied to the calculation of flood evolution in the Hook Bend-Linqing section. Through the comparative analysis with the PSO linear model and the least squares linear model parametric rate determination flood calculus, it is found that the accuracy of the nonlinear model based on PSO algorithm is higher than that of the two linear models, and the sum of the squared errors of the three typical floods in 1960, 1961 and 1964 is reduced by 0.9%, 6.2% and 1.6%, respectively, indicating that the parameter rate determination results of the nonlinear Mastingen model based on PSO are closer to the evolution process of actual floods.
LIU Chunhong; Li Chenggui; ZHANG Qingrong; etc
Abstract: The polishing method of immersion fixed eccentric tin grinding disc was adopted to study the influence of polishing liquid concentration, PH value, upper and lower grinding disc speed, polishing time and other parameters on the ultra-smooth surface roughness of glass-ceramic, and NT1100 interferometer was used for roughness measurement. The experimental results show that the roughness is greatly affected by the PH value. In the low concentration of weak alkali polishing solution, extending the polishing time can reduce the surface roughness value and obtain a high-quality surface, and the final measured surface roughness is Ra=0.37 nm.
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