Investigation on the communication network of long wire transmitting in remote welding

According to the characteristics of remote welding, including multiple parameters, real-time, and reliability of long wire transmitting, a distributing computer control scheme is adopted. A serial communication network between the master and the slavery computers is constructed. A synchro-control network among slavery computers is designed. Uniform message format and communication protocols are made. Considering intensive high-frequency noises at the welding zone, a quadruple check mode, including data sum check, parameter type check, welding parameters check and Exclusive OR （ XOR ） check, is adopted to assure the reliability of communication among multiple computers. Based on disturbing circuit, common circuit and sensitive circuit, the measures are brought forward to ensure the stabilization of communication network of remote arc welding by analyzing the wiring principle of anti-high-frequency interference of system bus, signal wires and shielding twisted-pair（STP） wires. The results provide the theoretical and practical references for the manufacture of remote welding robot and the quality of remote welding.

High gain-bandwidth product Ge/Si tunneling avalanche photodiode with high-frequency tunneling effect

This study presents a theoretical investigation of a novel Ge/Si tunneling avalanche photodiode（TAPD）with an ultra-thin barrier layer between the absorption and p＋ contact layer. A high-frequency tunneling effect is introduced into the structure of the barrier layer to increase the high-frequency response when frequency is larger than 0.1 GHz, and the-3 dB bandwidth of the device increases evidently. The results demonstrate that the avalanche gain and-3 dB bandwidth of the TAPD can be influenced by the thickness and bandgap of the barrier layer.When the barrier thickness is 2 nm and the bandgap is 4.5 eV, the avalanche gain loss is negligible and the gainbandwidth product of the TAPD is 286 GHz, which is 18% higher than that of an avalanche photodiode without a barrier layer. The total noise in the TAPD was an order of magnitude smaller than that in APD without barrier layer.

Polyphony of domestic dog whines and vocal cues to body size

In domestic dogs Canis familiaris,vocal traits have been investigated for barks and growls,and the relationship between individual body size and vocal traits investigated for growls,with less corre-sponding information for whines.In this study,we examined the frequency and temporal traits of whines of 20 adult companion dogs(9 males,11 females),ranging in body mass from 3.5 to 70.0 kg and belonging to 16 breeds.Dog whines(26-71 per individual,824 in total)were recorded in condi-tioned begging contexts modeled by dog owners.Whines had 3 independent fundamental fre-quencies:the low,the high and the ultra-high that occurred singly as monophonic calls or simul-taneously as 2-voice biphonic or 3 voice polyphonic calls.From the smallest to largest dog,the upper frequency limit varied from 0.24 to 2.13 kHz for the low fundamental frequency,from 2.95 to 10.46 kHz for the high fundamental frequency and from 9.99 to 23.26 kHz for the ultra-high funda-mental frequency.Within individuals,the low fundamental frequency was lower in monophonic than in biphonic whines,whereas the high fundamental frequency did not differ between those whine types.All frequency variables of the low,high,and ultra-high fundamental frequencies cor-related negatively with dog body mass.For duration,no correlation with body mass was found.We discuss potential production mechanisms and sound sources for each fundamental frequency;point to the acoustic similarity between high-frequency dog whines and rodent ultrasonic calls and hypothesize that ultra-high fundamental frequencies function to allow private,"tete-a-tete"com-munication between members of social groups.