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Graphene oxide (GO) was prepared by Hummers method and GO/1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) composite was prepared via an ultrasonic compounding method. The structure of GO was characterized using XRD and SEM, the thermal decomposition of HMX and GO/HMX composite was analyzed by DSC/TG test. The results show that interlayer space of GO increases markedly, the thermal decomposition process of HMX can be promoted with the nanolayer structure of GO, resulting the reduced thermal decomposition activation energy of about 50 kJ/mol with 1% GO.

A dual-rotor calculation model which can expand freely in the axial direction is established in this paper, and the effects of one-dimensional axial temperature distribution on critical speeds of the dual-rotor system are analyzed with finite element method. The temperature distribution of the dual-rotor system is given referring to that of similar aero-engine rotor system. Assuming that the left end temperature remains at 0 °C, and the highest temperature on the section of the high-pressure turbine disk is 0 °C, 200 °C, 400 °C, 600 °C, and 800 °C respectively, the critical speeds of the dual-rotor system are calculated, analyzed and compared. Calculation results show that, with the increase of the highest temperature of the dual-rotor system, the reduction percentage of the critical speeds increases, and the impact on the first critical speed is most obvious. When the highest temperature is 800 °C, the first critical speed of the rotor system excited by the low-pressure rotor reduces 13.13%, and that excited by the high-pressure rotor reduces 13.49%.

This paper examined the effect of the urbanization on CO2 emissions in China, using the semi-parametric panel data model. The results show that an inverted U-shaped relationship exists between urbanization and CO2 emissions in China and further development of urbanization is beneficial in reducing CO2 emissions.

This paper selects a load-bearing stage of an aeroengine compressor stator as study object to describe the model simplification method. Based on the criterion of cross section equivalence, the stator vanes are simplified into three versions of rectangular beams with variable cross section, using eight sections, four sections, and two sections respectively, to set up finite element model of the structure. Natural frequencies of the three simplified models are calculated and the results are compared with that of the original model. Comparison results show that the largest calculation errors of the first 10 natural frequencies using the three simplified models are-3.22%, -4.97% and-5.38%, respectively, but with this method, the model scale and computing time reduce significantly down to 3-4%, and 1-2% of the original model. The result shows that, the proposed method is applicable to relevant practical engineering.

Comparing with other High-level programming languages, C Sharp (C#) is more efficient in software development. While MATLAB language provides a series of powerful functions of numerical calculation that facilitate adoption of algorithms, which are widely applied in blind source separation (BSS). Combining the advantages of the two languages, this paper presents an implementation of mixed programming and the development of a simplified blind signal processing system. Application results show the system developed by mixed programming is successful.

This study is based on the graduation design for undergraduate course. In the paper, finite element analysis software ANSYS had been used to create the finite element model of a cannon barrel. On this basis, the vibration modal analysis of the barrel was conducted. Through the model analysis, the natural frequency and modal shape of the cannon barrel was obtained. The situations of stiffness strength and elasticity deformation about each part of the barrel were got by analysis of the modal shape. By this way, we can verify the rationality of the barrel design .Also it can provide improvements of the weak place of the structure for people to improve the stiffness and shooting precision of the gun, in order to make the dynamics characteristics of the gun more reasonable.

Excavating trajectory impact the production efficiency and overall performance of excavator directly [1]. Hence, it’s of very realistic significance to obtain the optimal excavating trajectory. Based on site test data, the point of tangency of the rack pitch line of the bucket rod and the pitch circle of the crowd gear were determined as the rotating center and the dynamic model of working mechanism was derived; due to the change law of the current and voltage of the hoist motor, the excavating process sections was separated from the excavating trajectory; log spiral model was chosen as the fitting function, and according to the following three judgment rules: maximizing soil volume in bucket, rationalizing the excavating time and minimizing the energy consumption of unit mass of soil in bucket, the optimal excavating trajectory was obtained and provided basis for the operation and design of the large mining excavator [2].

Based on the idea of system theory and highlighting the main aspects of the contradiction, the working device of mechanical excavator is simplified to fewer degrees of freedom dynamic model by analysis, and the main structures of influencing dynamic factors and wire rope are regarded as elastic bodies, other structures as rigid bodies; Starting from the theoretical dynamic characteristic curve of excavator, utilizing typical working conditions as calculation conditions, using Lagrange equation as a method to solve the dynamic integrated constraint system, we can establish the dynamic equations of working device and get the maximum dynamic load and dynamic load coefficient, and provide a reliable basis for selection of the dynamic parameter and calculation of structure strength.

To highlight the main factors, only the crowding shaft was taken as elastic component, while the other crowding system parts, such as girth, driving shaft and swing arm were taken as rigid components; the effects of damping were ignored; the dynamical model of excavator’s crowding system was simplified to a two degree of freedom model; mathematical and mechanical models were derived by Lagrange equation method; the locked rotor condition, when the bucket rod was perpendicular to the boom, was used as the calculation condition; the calculated dynamic load coefficient of the crowding system was compared with that in multi degree of freedom model and the result shows: to simplify calculation, it is practicable to replace multi degree of freedom models with two degree of freedom models in the preliminary design stage.

The external characteristic curve of engine is the basis of choosing engine, matching and optimizing dynamic performance correctly. At present, most models of the external characteristic curve of engine are carried out by using polynomial regression equation for fitting the external characteristic curve of engine. In this paper, an establishing model method of the external characteristic curve of engine based on F distribution testing is proposed. F test with variance analysis is implemented for obtaining the difference of square sum of return difference between the former equation and the latter equation. If the test doesn’t go through, it can rise one level automatically, until the difference about square sum of return difference of the before-after fitting equation is no significant can it stop. This method provides a theoretical criterion for establishing model of the external characteristic curve of engine. When it is applied to the engineering case, the model will have a higher fitting precision.

To obtain the concise relationship between the dynamic load and its influence factors, the single degree-of-freedom system was applied to simplify the crane working mechanism. Based on the sloping load, this paper analysed the main influence factors on the dynamic load and two relations were obtained:the relation between the dynamic load coefficient and the loading time;the other between the dynamic load coefficient and the natural vibration period. Due to the previous calculation and analysis, the suitable loading time and the dynamic load coefficient within the engineering permissible range were also obtained. The stiffness formula based on the loading time of the system’s elastic component was originally put forward. The result provided not only reliable basis to obtain the geometric parameter of the elastic component, but also feasible measures to prevent the dynamic load from increasing. Hence, it is effective to ensure the stable running of the equipment.

The primary purpose of this paper is to study the effects of temperature on crack propagation of nanocrystalline nickel by Molecular Dynamics (MD) simulations. Cracks are loaded in tension mode I. Results show that dislocation emission from a crack tip in nanocrystalline nickel due to the recombination of atomic lattice, then distortion of the crack tip promote crack propagation. The studies we have performed showed that temperature takes a great influence on the crack propagation and the crack shape, and we also found that the crack blunt obviously at high temperature.

Built-up columns are widely used in engineering structure, but it is confusing for designers how to determine the parameters of built-up columns. The paper based on the user's basic needs which are the minimum working radius and working load, would simplify working load, support force and hoisting force to the vertex of built-up columns. From the origin of design, and to analyze mechanic behavior of built-up columns, and have found the relationship between internal forces, that is, the axial force, the swing force, the support force, and the working load. In accordance with design experience, the relationship between axial internal stress and its total working stress, critical stress and limit of yielding, had been respectively determined. According to this knowledge to determine the mass and the geometrical parameters of major cross-sections and roots of built-up columns, and a comparison between the results and ones of examples calculations were made, and it was found that the results are reasonable. This will offer a design method of determining the major parameters of built-up columns at the phase of the preliminary design, and improve the independent design capability.

A novel liquid crystal monomer 1, 4-Di-[4-(3-acryloyloxyhexyloxy) benzoyloxy]-2-methyl benzene (LCM) was synthesized and characterized by 1H NMR, differential scanning calorimetry (DSC) and polarized optical microscopy (POM). LCM possesses liquid crystal phase between 68 to 124 °C. A f-ast response polymer stabilized cholesteric texture (PSCT) film was prepared based on LCM, and t-he response time was less than 1 ms, which can be applied in true 3D display. In addition, the morp-hology of the polymer network was investigated by scanning electron microscope (SEM).

Traditional ink based on natural pigment and soybean oil has disadvantages of poor temperature adaptive in application process. This project broke the limitations that stocks printing with traditional ink based on natural pigment and soybean oil could not be used for heating. Developing practical temperature-resistance environment-friendly ink based on natural pigment and soybean oil is of great importance. The experiment introduced the silicone material, and made full use of its characteristic. The Si-O bond of silicone can be 121 kcal/mole, and its molecular bond can not be broken down at a high temperature (or exposure to radiation). The property of high temperature resistance mainly depends on its unique functional group or long polymer chain structure. The experiment studied temperature resistance environment-friendly ink's performance in color, in order to improve its practical application value.

Large caliber naval gun weapon system in sustained and rapid firing process, produced high temperature and high pressure gas will form pulsed high temperature flow in barrel, causing the barrel being heated and cooled sharply and then being in bad environment, affecting the life of the barrel. The research object of this paper is based on 155mm naval gun, to utilize the theories of fluid mechanics and heat transfer and use ANSYS-CFX software, to simulate the heat response of the gun’s rifling original portion under interlayer active cooling, and to analyse the effects of structure parameters of interlayer cooling system and flowing parameters of cooling liquid on cooling performance using the principle of heat transfer enhancement, providing guidance for the optimization of the structure of the interlayer cooling system.

This paper presents two novel approaches for palmprint verification by scene match- ing. In a sense, the process of palmprint verification can be regarded as matching one palmprint template with another palmprint sample taken under conditions of different illumination, sensor pose geometry, or types of sensor, and making a decision of whether they belong to the same person or not. Enlightened by the idea of scene matching algorithms, two efficient approaches by scene matching are presented for palmprint verification. A sub-image from the user’s training palmprint is intentionally extracted, and stored as a template. In the verification stage, the sample image is directly matched with the template without the step of ROI (Region of Interest) extraction. Whether the sample image and the template are from the same person or not is decided by their matching scores. Experimental evaluation results on two databases clearly demonstrate the effectiveness of the proposed approaches.

In order to study the dynamic changes of the internal flow field physical quantities in the hydraulic buffer of a special equipment, based on the Computational Fluid Dynamics (CFD), a three-dimensional incompressible and viscous model under unsteady condition is created. The model keeps the control rod of varying diameter and non-working chamber cover, simulates the turbulent in the flow field of the hydraulic buffer of the special equipment with dynamic meshing technology. From the results, the distributions of velocity in flow field and pressure in chamber are got. It shows that there are negative pressure areas in the non-working chamber and that will lead to cavitation. The results give us a great reference to improve the structure of hydraulic buffer.

With the development of high power LED technology, junction temperature as a key factor constrains the performance and the service life of LED, and the main parameter of junction temperature is thermal resistance. Therefore, how to measure the thermal resistance of high power LED quickly and accurately plays an important part in improving the performance and the service life of LED. In this paper the accurate and fast measurement equipment was applied to study the thermal characteristics of high power LED. The forward-voltage based method was conducted to measure the junction temperature of high power. Then, support vector regression (SVR) combined with genetic algorithm (GA) for its parameter optimization, was proposed to establish a model to predict the thermal resistance of high power LED. The prediction performance of GA-SVR was compared with those of BPNN model. The result demonstrated that the estimated errors GA-SVR models, such as Mean Absolute Relative Error (MARE) and Root Mean Squared Errors (RMSE), all are smaller than those achieved by the BPNN applying identical samples.

This paper uses unary compressibility fluid movement theories and combines with years of design practice, calculates airflow movement parameters of the nanometer fiber cartridge filter cleaning system, discusses relations of the parameters and the effect on the cleaning efficiency of the parameters. The theoretical analysis results can make a significant contribution to the basis for the subsequent works.

Whether selection of chip removal air volume is reasonable or not, do affect the performance of blasthole drill and bit’s life. How to calculate air volume always make the designers confused. In this paper, writer use theory of gas-solid two-phase flow and energy principle combined with characteristic of rock ballasts from the mine site to determine particle rising speed, free floating speed and air flow rate of the rock ballasts. And according to the relation between particle and particle group’s floating speed calculate floating speed and the corresponding chip removal air volume among different diameter of particle of the same minerals. It can provide a method of calculation to designer, which is very reference value to for the practical application.

In this study, liquid film perturbed pressure equation is derived firstly using a Taylor Series expanding pressure formula. By linear film assumption, the axial stiffness and damping coefficients of the mechanical seal are derived. Then kinematical equation of the rotating shaft-mechanical seal system is established. The research focus on solving response of the rotating shaft-mechanical seal system and leakage of the mechanical seal when the rotating shaft is under different frequencies excitatied or under frequency disturbed in different form excitatied in this paper. The analytical results show that response of the rotating shaft-mechanical seal system can finally be close to the stable state, when excitatied frequency of the rotating shaft is disturbed in different form. But for amplitude of the displace between the stationary ring, rotating ring and rotating shaft occurs mutation point at the time when the excitatied frequency is disturbed, meanwhile the excitatied frequency of the rotating shaft is disturbed in rectangular pulse form or in instant maximum pulse form. It will cause liquid film thickness to happen mutation until the leakage increases and mechanical seal fails at last. The study results show that the sealing performance of mechanical seal and excitatied frequency of the rotating shaft has closely positive correlation. The rotating shaft-mechanical seal system can be optimization design and performance prediction based on the study of this paper.

The experimental study results show that the system’s nonlinear characteristics, incluing the dynamic responses of the poincare mapping, the bifurcation plots, three-dimensional waterfalls diagrams etc. The effects factors of system experiment are studied and analyzed, including the misalignment and the rub-impact stiffness on system responses. So, the faults characteristics of the misalignment and the rub-impact of the rotation shaft-mechanical seal system on the drainge motor and drainge pump are also gained by the experiment. The dynamic performance of the system show nonlinear characteristics in different working conditions. The rotating shaft-mechanical seal system on the drainge motor and drainge pump can be optimization design and performance prediction based on the studied results of our work. The experiment’s results show that: the multiple frequencies are produced of the rotating shaft-mechanical seal system on drainge motor and drainge pump, and the frequencies of 1-time and 2-time are dominating components under the exciting force effects of misalignment and imbalance. At the fault state of misalignment coupling rub-impact, the multiple frequencies including 2-time, 3-time, 4-time and so on, will be induced under the critical speed. Over the value of the critical speed, will cause the phenomenon of frequency demultiplication and chaos. With rub-impact stiffness value increased, the phenomenon of frequency demultiplication and chaos are induced more frequently; with the degree of misalignment increased, the phenomena of chaos will decrease and the system will tend to be the stable state.

In the present paper, monodisperse poly(lactic acid) (PLA) microspheres (MS) containing the enrofloxacin (ENRO), were manufactured by using a modified solid in oil in water (S/O/W) emulsion solvent evaporation method. In order to prepare PLA microspheres with a higher drug loading efficiency by this modified technique, the test of stability and productivity of the primary emulsion was preliminary examined by change species or concentration of the oil-soluble surfactant and the ratio of water and organic solvent. Firstly, enrofloxacin polylactic acid microspheres (ENRO-PLA-MS) were producted, then the morphology and particle size distribution were estimated by scanning electron microscopy (SEM), its encapsulation efficiency and drug loading efficiency were assessed by High performance liquid chromatography (HPLC). In vivo conditions were simulated by an stable release buffer to obtain a detailed release and polymer degradation profile. Consequently, the ENRO-PLA-MS had a denser structure with a smooth, pore-free surface, the preparation of microspheres was simple, the prepared microspheres had excellent controlled drug release characteristics in vitro.

Drug was encapsulated in a novel copolymers of poly(lactic-co-glycolic acid) (PLGA) to investigate the sustained-release formulation of drug loaded polymer microspheres delivery system. Used a modified solid-in-oil-in-water (S/O/W) emulsion solvent evaporation method to prepare microspheres, its morphology and particle size distribution were estimated by scanning electron microscopy (SEM), the profile of in vitro drug release were assessed by High performance liquid chromatography (HPLC). Finally, an stable release buffer was utilized to obtain a detailed drug release profile, which was analyzed by HPLC also. Results showed that the microspheres morphology, encapsulation efficiency and the cumulative drug release efficiency were appropriate for veterinary medicine using. The modified preparation method was simple and optimized, PLGA microspheres with excellent controlled-release characteristics may serve as drug delivery carrier and may prolong the drug sustained-release effect.

According to the effective of the displacement of crane boom to rated capacity, establishing a mechanical model with a prototype. After calculation and analysis, take drastic measures to ensure the rated lifting capacity. And the measures are worth popularizing.

Drilling parameters have great influences on hole accuracy and defect production. In this study, single factor test is applied to obtain the relationship between the torque deviation and the spindle speed n at different feeds per revolution fr. White Light Interferometer (WLI) is applied to measure the hole shape. Based on the frequency domain analysis of torque deviation, the cause of hole shape deviation is investigated. Relationship between the hole shape accuracy and drilling parameters is established, which can be used to predict the hole shape by analyzing the torque deviation. Moreover, the reasonable processing parameters can be selected to obtain drilling hole with ideal shape and satisfying production efficiency.

Two new conjugated copolymers, PFPh and PFTDP, comprised of alternating 9,9-dioctylfluorene and phthalimide (Ph) or thieno [3, 4-c] pyrrole-4,6-dione (TPD) have been synthesized via Suzuki coupling reaction. Polymeric light-emitting diodes (PLED) were fabricated with an ITO/PEDOT: PSS/PVK/Polymer/BCP/Alq/Ca:Ag configuration. The maximum brightness and maximum current efficiency of PLED are 2600cd/m2and 2.52 cd/A for PFPh, and 2300cd/m2and 1.13 cd/A for PFTDP, respectively, which are significantly improved compared with the reported alternating fluorene-unsubstituted phenylene/thiophene systems.

As regards the solution of ensemble elastic stability of assemble and lattice boom with complicated boundary conditions are rarely discussed, it is always plaguing designers. In this article, through analyzing the characteristics of vice-boom and vice-boom strut bar be caused complex deformation under load, based on the deformation relationship among vice-boom, vice-boom strut bar and main-boom ends, establishing elastic stability theory mathematical-mechanical model, using the theory of calculating the Euler critical force, proposed the method and numerical value to determine length conversion factor of assemble boom. This article has an inaugural significance of theory.

This paper make the rigid support Jeffcott shaft-mechanical seal system as the research object. Firstly, it establishes the equivalent stiffness matrix and damping matrix of the rotation shaft with mechanical seal in the fixed-coordinate system, then derives the motion equation of the shaft with mechanical seal and applies the numerical simulation method to analyze and gain the vibration characteristics of the rotation shaft with mechanical seal system. Numerical simulation results show that: when the rotation shaft works at the speed of the subcritical speed, the trajectory of centre will change with the speed of the shaft. When the shaft works at the speed of the second supercritical speed, the trajectory of centre will be a limit circle. When the shaft works at the speed of the subcritical speed, the vibration response appear 1X, 2X, 3X and so on component of the vibration, and when Ω is 1/2, 1/3 and so on, 2X, 3X and so on component of vibration is biggest; when the shaft works at the speed of the second supercritical speed, 2X and 2X above component of the vibration is very small, even to zero, and then the trajectory of the centre is a limit circle. Whenhminis different, amplitude-frequency diagram of the X direction of the rotation shaft is different. Whenhminis bigger ,1X, 2X, 3X component of the vibration is bigger.

In this paper, three-dimensional solid contact finite element model of pin connector was build,and used this model to make careful checks of a variety of analytical algorithms of dangerous section’s stress of lug ,finally established reasonable analytical algorithms of dangerous section’s stress of lug.

Cemented carbide has relatively good mechanical properties, so it is widely used as cutting tools. In this paper, a sliding wear test at high ambient temperature between cemented carbide tool material and ceramic was carried out using a ball-on-disc wear-test machine. The characteristics as to wear rate and friction coefficient were investigated. The special wear rate increased with an increase in operating temperature. The cemented carbide material with addition of TiC phase gave better wear resistance than cemented tungsten carbides at elevated temperature. SEM technology was adopted to observe the worn surfaces of specimens and wear mechanism were simultaneously discussed.

The jib is an important component for the tower crane. The reliability of the tower crane jib has a direct impact on the safety production. In the current crane industry, the traditional allowable stress method is still the main method for designing tower crane jib. As a result, the reliability of the tower crane jib cannot be given quantitatively. In this paper, by using the probabilistic method, the reliability of a tower crane jib is worked out, and a design way based on the reliability for the tower crane jib is provided.

Working condition and structure for crane boom is quite complex. In order to ensure the safety of crane, there is a high requirement for reliability. In this paper, probabilistic finite element method is used to analyze the reliability of crane boom. Parametric finite element model of crane boom is built and uncertain parameters are obtained by analyzing characteristics of dimensions, materials, loads and constraint conditions for crane boom. Uncertain parameters like structural dimensions, material parameters and loading parameters, etc are processed discretely and reliability of crane boom is obtained by using Probabilistic Design System (PDS) of ANSYS. Meanwhile, we can get the main parameters which affect reliability of crane boom and how much their influences will be by sensitivity analysis.

In the present study, the finite element model of machining carbon fiber reinforced aluminum matrix composites with representative fiber orientation of 90 degree is established with the following developments: (i) a Johnson-Cook constitutive model of each component in the multi-phase composite materials; (ii) a failure model of the composite material based on physical separation criterion; (iii) the interface between fiber and matrix defined by a interaction. This simulating method can be developed to each kind of fiber reinforced composite materials.

Derricking device of flexible transmission is widely applied in crawler cranes, while its derricking speed hasn't been studied very well. In this paper, the kinematics model of derricking device is firstly established. Next, the dynamic analysis is done. A succinct method based on the load's prescriptive swing angle is put forward. The reasonable speed and acceleration of derricking device are determined according to the method. The adopted values provide a reliable basis for design and analysis. The study puts a way for the following work. All in all, it is innovative.

In this paper, multi-linear regression and artificial neural network (ANN) models have been developed to predict surface roughness in high-speed milling of 7050-T7451 aluminum alloy. Surface roughness is taken as the response variable, while cutting speed, feed per tooth, radial depth of cut and slenderness ratio are taken as independent input parameters. An orthogonal experiment design is developed to conduct experiments. The measured values of surface roughness are used to find the regression coefficients and train the neural network for prediction of surface roughness. Predicted values of surface roughness by both models are compared with the measured values.