126 research outputs found

    Hydraulic motor with swinging planetary drive of bevel gears and its force & efficiency calculation

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    A new kind of hydraulic motor with offset swining planetary drive of bevel gears and the application in Capstan is presented; the researched of the calculation of the efficiency of the mechanism is made. Compared to the former structure, new kind of structure has many advantages over that of the old structure. The hydraulic driving system in the traditional derrick car is: hydraulic motor drives a reducer, and then the reducer in turn drives a capstan. Another hydraulic driving system is: an axial piston motor and an internal cycloid pinwheel drive are applied, so that the reducer and the capstan are combined into one so that simplified the transmission system. In the third version, a hydraulic motor is applied, which can be considered as the combination of hydraulic motor with axial piston and the planetary reducer and then drives the capstan, so that simplified the transmission system as well. The new kind of hydraulic motor with offset swing planetary drive of bevel gears, which combined the hydraulic motor, the internal planetary reducer with bevel gears, and the capstan together, is the most compact structure. It is of more advantage in the occasion when space is extremely limited. In the paper, two kind of construction of this mechanism is presented, and the analysis of the efficiency of this kind of transmission is made as well

    Highly effective way in five-axis sculptured surfaces machining using flat-end cutter

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    This paper applied the concept of “contact” in Differential Geometry into the machining of the sculptured surface. I presented the contact principle of the machining of complicated surfaces, using the circumference circle of the cylindrical cutter to sweep the curved surface instead of ball-end mill. This is highly effective method. In this paper an theory for machining complicated surface is presented. By using a flat-end mill instead of ball-end mill, and adjusting the axis relate to the surface, the two surfaces, The swept surface and the required surface, has the same curvature, up to as high as 3th order

    The second fundamental law of gearing and contact stress calculation of high order contact gearing

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    After an extensive research on the fundamental theory, the theoretical basis for the Logix gearing will be presented in this paper. This includes the theory for gear meshing with high degree of contact. In comparison to previous studies, the theory of this paper is more restricted going beyond third order parameters into the fourth order, the teeth profile had one order of contact higher than that of the Logix gearing. So that further improved the contact strength of tooth profile. A large category of gearings with high order of contact was presented, while the Logix gear is only one of them, or the special example in realization of my theory. In the Logix gearing, the zigzag curvature center curve of media rack does not always lay about the pitch line and does not extend along the pitch line continuously and steadily. It goes forward and returns. So that, in terms of properties of the transverse engagement, the Logix gearing has not much improvement over the traditional Novikov gearing (in which the transverse engagement is temporally). In my gearing the curvature center of basic rack extend along the pitch line continuously and steadily. The transverse engagement factor is larger than that of Logix gearing

    Arctic weather routing: a review of ship performance models and ice routing algorithms

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    With the accelerated melting of the Arctic sea ice, the opening of the Northeast Passage of the Arctic is becoming increasingly accessible. Nevertheless, the constantly changing natural environment of the Arctic and its multiple impacts on vessel navigation performance have resulted in a lack of confidence in the outcomes of polar automated route planning. This paper aims to evaluate the effectiveness of two distinct models by examining the advancements in two essential components of e-navigation, namely ship performance methods and ice routing algorithms. We also seek to provide an outlook on the future directions of model development. Furthermore, through comparative experiments, we have examined the existing research on ice path planning and pointed out promising research directions in future Arctic Weather Routing research

    The Effects of Scleral Collagen Cross-Linking Using Glyceraldehyde on the Progression of Form-Deprived Myopia in Guinea Pigs

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    To investigate the effects of collagen cross-linking using glyceraldehyde on the biomechanical properties of the sclera and the axial elongation of form-deprived myopia in the guinea pig. Thirty-six guinea pigs were randomly assigned to four groups: FDM (form-deprived myopia); FDMG (form-deprived myopia treated with glyceraldehyde); FDMS (form-deprived myopia treated with 0.9% isotonic sodium chloride); and normal control (free of form-deprivation). FDM was achieved in the right eye using a latex facemask. The right eye in FDMG was treated with a posterior subtenon injection of 0.5 M glyceraldehyde; 0.9% isotonic sodium chloride was administered to the right eye in FDMS group using the same method. Axial length, refraction, and stress-strain of the sclera were measured at scheduled time points. The treated eyes were also examined histologically by light microscopy. It was found that glyceraldehyde treatment significantly increased the stiffness of the sclera in the FDM eyes and abnormalities have not been observed in the retina and optic nerve of the treated eyes. But the development of myopia was not affected

    The shortcomings of quality evaluation of postgraduate training under the orientation of “five only” and its countermeasures

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    This paper analyzes the causes and the current situation of the traditional education evaluation in China based on the goal of breaking the “five only”, and discusses its drawbacks in terms of distorting the real level of scholars, hindering the diversified innovation of schools, driving the academic style and merit, and harming the national education development. Finally, the paper proposes countermeasures to break the “five only” reform in terms of establishing a new style of education, improving result evaluation, strengthening process evaluation, exploring value-added evaluation, and improving comprehensive evaluation. The paper may be useful to promote the reform of postgraduate training quality evaluation and improve the institutional mechanism of moral education

    Current Situation and Countermeasures of Enshi’s Agricultural Economic Development Based on information technology

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    -Agricultural economic development has great significance of China to win the campaign against poverty, and the intelligent agriculture based on information technology is the cornerstone of rural revitalization strategy. This paper takes Enshi Tujia and Miao Autonomous Prefecture as an example, discusses the advantages and disadvantages of its current agricultural economic development, and puts forward some countermeasures and suggestions based on the utilization of information technology
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