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

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

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

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

Nanogranular MgB2 thin films on SiC buffered Si substrates prepared by in-situ method

MgB2 thin films were deposited on SiC buffered Si substrates by sequential electron beam evaporation of B-Mg bilayer followed by in-situ annealing. The application of a SiC buffer layer enables the maximum annealing temperature of 830 C. The Transmission Electron Microscopy analysis confirms the growth of a nanogranular MgB2 film and the presence of a Mg2Si compound at the surface of the film. The 150-200 nm thick films show a maximum zero resistance critical temperature TC0 above 37 K and a critical current density JC ~ 106 A/cm2 at 11K.Comment: 7 pages, 6 figures, submitted to Applied Physics Letter

STUDY OF AL/A-SIC/C-SI(P)/AL STRUCTURES FOR PV APPLICATION

Plasma CVD reactor was used to grow a-SiC:H on p-type crystalline silicon substrate. Identification of chemical bonds in the structure of thin amorphous layer by Fourier transform infrared spectroscopy (FTIR)and Raman spectroscopy methods was performed. DC characterization was performed in order to obtain basic electric and PV parameters of prepared sample. AC impedance spectroscopy characterization was performed in order to detect the frequency response of Al-a-SiC/c-Si(p)/Al heterojunction. The analysis of these characteristics, using the impedance spectroscopy method, has allowed the construction of the electrical equivalent circuit (EEC) of the investigated structures. EEC contains series connections of series resitance and parallel combination of thin film capacitance shunted by resistance and constant phase element (CPE) shunted by resistance. The values of the parameters of the circuit elements have been determined at room temperature in the dark and on illuminated samples in the frequency range from 1 Hz to 1 MHz and also at different forward bias voltages. The negative capacitance phenomenon was observed at lower frequencies

Properties study of silicon carbide thin films prepared by electron cyclotron resonance plasma technology

Silicon carbide films were deposited at two deposition temperatures 350 °C and 450 °C by means of ECR plasma reactor with two gas mixtures: (1) gas mixture, SiH4 (5 sccm), CH4 (14 sccm), Ar (6 sccm), NH3 (2 sccm) and (2) gas mixture SiH4 (5 sccm), CH4 (14 sccm), H2 (6 sccm), NH3 (2 sccm). The concentration of species in the SiC films was determined by Rutherford backscattering spectrometry (RBS) and elastic recoil detection (ERD) analytical method simultaneously. Chemical compositions were analyzed by infrared (IR) spectroscopy. Photoluminescence (PL) spectra were measured at 300 K. The RBS and ERD results showed that the concentrations of Si and C in the films are practically the same. The concentration of hydrogen decreased from 30 to 22 at.% with an increasing sample deposition temperature. The films contain a small amount of nitrogen and oxygen. IR results showed the presence of Si-C, Si-N, Si-H, C-H and Si-O bonds. PL results showed the decrease of the PL intensity with an increasing sample deposition temperature

A Quantum Mechanical Study of the <i><b>k</b></i>–<b><i>j</i></b> and <b><i>k</i></b>′–<b><i>j</i></b>′ Vector Correlations for the H + LiH → Li + H₂ Reaction

We have characterized the stereodynamics of the H + LiH (<i>v</i> = 0, j = 0–1) reactive collisions leading to H₂ formation through the quantum mechanical analysis of the <i><b>k</b></i>–<b><i>j</i></b> and <b><i>k</i></b>′–<b><i>j</i></b>′ vector correlations that describe the polarization of the reactants and products, respectively. Our results, which cover the collision energy interval between 10^–4 and 1 eV, are unexpectedly complex given the apparent simplicity and featureless nature of the potential energy surface for the LiH₂ system and point toward the existence of a dynamical barrier connected to the centrifugal barrier. Both reactants and products, in particular the second ones, display strong directional preferences in the cold region that indicate a bias for collinear approaching and departing geometries and are independent of the final state of the products. As more energy is available for the reaction, the polarization of reactants and products becomes weaker and strongly dependent on the final state. While stereodynamical control is feasible and significant in the cold region, its extent becomes negligible for other energetic regimes