A method of tuning PID parameters for P-GMAW based on physical experiments

To improve welding quality, a method of proportional-integral-differential （PlD） parameters tuning based on pulsed gas metal arc welding （P-GMAW） control was put forward. Aiming at the request of dynamic responsiveness of PGMA W constant current control, a self-developed welding waveform wavelet analyzer was employed. By tuning the proportional parameter, integration time and differential time in sequence, the optimal PID parameters could be achieved. The results showed that, due to the PID parameters tuned by this method, the welding process was stable and the weld bead appearance was nice. The requirement of dynamic responsiveness of P-GMAW constant current control was fully met.

LED Driving Power Online Detection System

LED driving power is a necessary product for LED lighting;the behaviors of pursuing low-cost of some small and medium- sized enterprise producers in China directly affect the quality of LED power. Therefore, it is necessary to detect the reliability of the LED driving power. There are 4 main factors for the over-burning of the LED driving power: lightning oscillation frequency, voltage mutation frequency, switch motion frequency and static discharge frequency. For the above problems, this paper raises the LED driving power online detection system, including: surge voltage input module, main control module, pulse width modulation module, power module, thyristor control module, current transformer, amplifier, RMSDC conversion module, A/D conversion module, display module, main control module connecting to surge voltage input module. The main operating principle is that the main control module connects the pulse width modulation module, which connects the thyristor control pole of the thyristor control module, the first anode thereof connects the power module;the primary side of current transformer connects the second anode of the thyristor control module through two wire switches, and the secondary side thereof connects the amplifier, which connects the RMS-DC conversion module;RMS-DC conversion module connects the A/D conversion module, which connects the main control module;the main control module also connects the display module. In addition, the project also provides the detection functions of LED output current, voltage digital display and different loads.

On Translation Errors and Culture Deviations in China English from Angle of Language Inclusivity

Any language must have the inclusivity of its own,otherwise it can hardly get developed. The English language has got the most powerful inclusivity, which makes itself the lingua franca of the world. However, as one of language varieties, China English develops with a lot of translation errors and culture deviations, which makes itself doubtful. As a result, a view comes into being that none errors can be permitted in China English, otherwise China English couldn't exist. But finally, it turns out that translation errors and culture deviations in China English are acceptable due to the language inclusivity.

Crystal Boundary of Chemical Vapor Deposited Diamond Films

CVD diamond films were synthesized by the chemical vapor deposition method.The crystal boundary was investigated using transmission electron microscopy and scan electron microscopy.The second grains facilitate the more compact film formation.No micro-holes are seen among diamond grains in the films but there are micro-holes in the interface of film/substrate.The second grain and the primary grain would keep the twin relationship of<110/70.5°.A lot of micro-twins are observed in fivefold twin grains but there is a zone of non twins which is like a strip along the fivefold twin boundary.Two microtwins keep the twin relationship of<110/70.5° with the fivefold twin matrix.The width and length of microtwins are about 3 nm and 32 nm,respectively.

Significant enhancement of crystallization kinetics of polylactide in its immiscible blends through an interfacial effect from comb-like grafted side chains

A significant enhancement in isothermal crystallization kinetics of biodegradable polylactide(PLA) in its immiscible blends can be accomplished through blending it with a comb-like copolymer. PLA was blended with poly(ethylene glycol) methyl ether acrylate(PEGA) and poly[poly(ethylene glycol) methyl ether acrylate](PPEGA, a comb-like copolymer), respectively. The results measured from phase contrast optical microscopy(PCOM) and differential scanning calorimetry(DSC) indicate that PLA and PEGA components are miscible, whereas PLA and PPEGA components are immiscible. The study of crystallization kinetics for PLA/PEGA and PLA/PPEGA blends by means of polarized optical microscopy(POM) and DSC indicates that both PEGA and PPEGA significantly increase the PLA spherulitic growth rates, G, although PLA/PPEGA blends are immiscible and the glass transition temperatures of PLA only have slight decreases. PPEGA component enhances nucleation for PLA crystallization as compared with PEGA component owing to the heterogeneous nucleation effect of PPEGA at the low composition of 20 wt%, while PLA crystallization-induced phase separation for PLA/PEGA blend might cause further nucleation at the high composition of 50 wt%. DSC measurement further demonstrates that isothermal crystallization kinetics can be relatively more enhanced for PLA/PPEGA blends than for PLA/PEGA blends. The "abnormal" enhancement in G for PLA in its immiscible blends can be explained by local interfacial interactions through the densely grafted PEGA side chains in the comb-like PPEGA, even though the whole blend system(PLA/PPEGA blends) represents an immiscible one.