Subjects: Computer Science >> Computer Application Technology submitted time 2023-02-15 Cooperative journals: 《桂林电子科技大学学报》
Abstract： Aiming at the inefficiency and uncertainty of the artificial selection of cylindrical process dimension parameters of
shaft parts and the difficulty of sharing and transmitting related process knowledge between heterogeneous CAPP systems, a
method for automatically generating cylindrical process dimension parameters of shaft parts based on ontology is proposed.
According to the process knowledge of design feature analysis, machining plan reasoning, process dimension parameter selection
and other process knowledge involved in the process of generating cylindrical process dimension parameters of shaft
parts, a knowledge representation model consisting of part structure layer, design feature layer, feature mapping layer and
processing feature layer is constructed. The web ontology language OWL is used to represent the knowledge model ontology,
and the meta-ontology model of the cylindrical process dimension parameters generation is constructed. The semantic
web rule language SWRL is used to construct the inference rules related to the generation process of cylindrical process dimension
parameters, and the automatic generation algorithm for cylindrical process dimension parameters is designed. The
Jess inference engine is used to realize the automatic generation of cylindrical process dimension parameters, and the feasibility
of the method is verified through an example.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-02-14 Cooperative journals: 《桂林电子科技大学学报》
Abstract： In order to improve the thermal conductivity of thermal interface materials, reduced graphene oxide/copper composite
materials were prepared by electrophoretic deposition, and the effects of reduced graphene oxide/copper, multilayer
graphene and nano-silver on the thermal conductivity of epoxy resin were compared and analyzed. The microscopic morphology
of the reduced graphene oxide/copper composite material was characterized by scanning electron microscopy. Thermal
constant analyzer, digital viscometer and contact thermal resistance tester were used to control and test the thermal conductivity,
viscosity and interface thermal resistance of epoxy resin-based composite thermal interface materials. The results
show that the experiment successfully prepared reduced graphene oxide/copper, and the metal copper particles were evenly
distributed between graphene sheets; in addition, the thermal conductivity of reduced graphene oxide/copper, multilayer
graphene, and nano-silver to epoxy resin both have improved. When the mass fraction of the reduced graphene oxide/copper
composite material is 30%, the thermal conductivity of the epoxy resin-based composite thermal interface material is increased
by 4.5 times. Under a pressure of 0.9 MPa, the interface contact thermal resistance is 37.06 mm2·K·W-1, which
is 35.9% lower than when no interface material is added (the interface contact thermal resistance is 57.84 mm2·K·W-1
when no thermal interface material is added.). High thermal conductivity materials can increase the thermal conductivity of
epoxy resin-based thermal interface materials and significantly improve the heat transfer performance of the contact surface.
Subjects: Optics >> Optical design and fabrication submitted time 2022-10-19 Cooperative journals: 《桂林电子科技大学学报》
Abstract： In order to better choose a suitable auxiliary objective lens, this article is based on the working principle of the
auxiliary objective lens, starting from both theoretical deduction and experimental simulation, firstly, the structure optimization
design of the common double glued auxiliary objective lens is carried out. According to the design requirements, the
initial structure of the auxiliary objective lens was reasonably selected, and various aberrations were theoretically deduced.
Finally, based on the initial structure and optimization goals, the optical design software OSLO is used to optimize the structure
and aberration analysis of the two forms of auxiliary objective lenses. Afterwards, the design of the innovative double
cemented-thick meniscus auxiliary objective lens was optimized. The structural parameters of the similar lens in the literature
were used as the initial structure of the design. OSLO optical software and design experience were used to optimize the
structure and analyze aberrations. And correction. Finally, the two types of auxiliary objectives are compared and analyzed.
The results show that the parameters of the two types of auxiliary objectives after optimization can meet the design requirements,
but the double-bonded-thick meniscus type auxiliary objective is more suitable for large images. The optical system
of the surface.
Subjects: Dynamic and Electric Engineering >> Power Machinery Engineering submitted time 2022-10-19 Cooperative journals: 《桂林电子科技大学学报》
Abstract： Aim to the present situation that the multi-point support electric leveling device is prone to virtual leg phenomenon in the leveling process, a method to determine the virtual leg of multi-sensory electric leveling device based on inclinationspin and output current of servo motor drive controller was proposed. The structure composition model of commonly used four-point support electric leveling device was constructed. Meanwhile, a leveling platform model was established by taking four-point support electric leveling device as an example. The principle of the proposed method, the decision strategy of pursuing height and multiple perception, the decision method of virtual leg and the decision procedure flow of the specific implementation process are described in detail, can effectively eliminate the phenomenon of virtual legs without adding new configurations, and can provide reference for automatic leveling and preventing virtual legs of construction machinery and land defense vehicle platform equipment.
Subjects: Physics >> Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics submitted time 2022-09-26 Cooperative journals: 《桂林电子科技大学学报》
Abstract： As a heat pipe occupying a place in the field of heat transfer, the PHP is widely used in electronic heat dissipation
equipment,and regarded to be one of the heat dissipation components that have great development prospects under the conditions
of extra high heat flow density and power consumption. With the maturity of nanotechnology, Nano fluid has also become
an innovative research in the traditional field of heat dissipation and heat transfer. Therefore, it is extremely important
to explore the change mechanism and change law of the operation and thermal characteristics of the pulsating heat pipe in different
magnetic field environments. Through the use of an external magnetic field to strengthen the experimental research on
the heat transfer of the nano-magnetic fluid pulsating heat pipe, a visualization experiment platform for heat transfer testing
of the nano-magnetic fluid pulsating heat pipe was built. The temperature distribution and heat transfer rate of the plate-type
pulsating heat pipe under the action of the magnetic field size of 25, 5, 1 and 0 mT and different magnetic field directions are
respectively measured. The influence of factors such as nano-magnetic fluid, heat load power consumption, magnetic induction
intensity and magnet placement position on its heat transfer performance is studied. The experimental results show that
the use of Fe3O4/ethanol nanofluid as the working fluid can significantly enhance the heat transfer performance of the pulsating
heat pipe under the action of a magnetic field. Especially under high heat flux loading, this can provide a reference for
the working conditions of ultra-high heat flux density and power consumption.
Subjects: Materials Science >> Metals and Alloys submitted time 2022-09-26 Cooperative journals: 《桂林电子科技大学学报》
Abstract： The microstructure and properties of Ag-TiN ceramic coatings were studied by DC magnetron sputtering at different power (60 W, 110 W and 150 W). Scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction were used to analyze the morphology and microstructure of the coating surface and cross section. The wear resistance of the coating was analyzed by reciprocating friction and wear tester. The results show that the coating thickness of the sample is 2.941 under three groups of power、3.625、5.023 μm. The weight percent of Ag on the surface is 50.97 wt%, 70.42 wt% and 91.25 wt%, and the main phases on the surface are Ag、TiN and TiO2; With the power increases, the grain size of the coating decreases and the coating becomes more uniform and compact; Ag particles diffuse from the coating to the surface and act as lubricant, which reduces the friction coefficient of the ceramic coating. The friction coefficient of the sample decreases by 31% at 110 W sputtering power; In the wear test under 10 N and 20 N load, the wear loss of the coating surface is reduced by more than 33%, and the properties are increased by 1.41 and 1.31 times compared with the base material. The Ag-TiN coating can effectively improve the surface microstructure and wear resistance of titanium alloy. Comprehensive analysis shows that the microstructure of the coating prepared at 110 W sputtering power is good, the friction coefficient is low, and the wear resistance is the best.
Subjects: Mechanical Engineering >> Mechanical Manufacture and Automation submitted time 2022-09-26 Cooperative journals: 《桂林电子科技大学学报》
Abstract：
To test the rationality of the power system for a fuel cell commercial vehicle, the models of energy source (including fuel cell stack and battery pack), electric motor system (including electric motor and its controller) and driveline are built in Matlab. A global optimization energy management strategy based on dynamic programing is adopt to analysis the vehicle’s fuel economy with the European typical drive cycle under three load modes (including no-load, half-load and fullload). Simulation results show that the energy source employed satisfy the vehicle’s power requirements at the selected drive cycle, while with the increase of on-board load, the terminal SOC of battery gradually deviates from the initial value, which will limit the commercial vehicle’s dynamic performance in the long term cycles with a large on-board load. Verification results for the vehicle point that great power on-board fuel cell stack should be considered in the following research and vehicle verification.
Subjects: Mechanical Engineering >> Mechanical Manufacture and Automation submitted time 2022-09-26 Cooperative journals: 《桂林电子科技大学学报》
Abstract： Aiming at the problem of low efficiency caused by complex and redundant calculation of robot dynamics model, a
programmed modeling method is proposed. Taking the Stanford Arm with six degrees of freedom as an example, the dynamic
model based on Lagrangian equation is established by using this method. According to the core idea of "forward analysis,
reverse output", the recursive process of the model is analyzed emphatically. On the basis of verifying the correctness of
the model, the indexes such as the dimensions and running time of the Stanford Arm model based on the PMM and the conventional
Lagrange equation without the use of the PMM are compared. The results show that relative to the conventional
Lagrange method, the complexity of the model established by PMM is reduced by 67.6%, and the computational efficiency
is increased by 66.3%. Stanford Arm is a complete constrained system. PMM is extended to underactuated nonholonomic
constrained systems, numerical simulation and physical prototype experiment analysis are carried out by using partial feedback
linearization control algorithm which is closely related to the model, it’s reliability and effectiveness of the programmed
modeling method are verified, which provides a modeling method with higher efficiency and better versatility for different
types of robots.
Subjects: Mechanical Engineering >> Machinofacture Technique and Equipment submitted time 2022-05-25 Cooperative journals: 《桂林电子科技大学学报》
Abstract：在电子封装领域中,所用的无铅钎料主要是二元或者三元Sn基共晶或近共晶合金,其基体相为富Sn相。为得到富Sn相的力学性能及应力-应变关系,由纳米压痕试验测试获得了富Sn相的弹性模量与硬度,并得到载荷-位移曲线。采用有限元反演分析的方法确定了富Sn相的特征应力和特征应变,并由量纲函数确定应变强化指数。将特征应力和特征应变强化指数等参数代入幂强化模型中,计算得到富Sn相的屈服强度为31.51 MPa,并最终确定富Sn相的应力-应变关系函数表达式。
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