Sensing and gait planning of quadruped walking and climbing robot for traversing in complex environment

In this paper, a general study on improving adaptability of quadruped walking and climbing robot in complex environment is presented. First, a sensing system composed of range and gyroscope sensors in a novel arrangement is developed. By combining the sensing signals and the internal state of the robot, the surface geometry of the environment is sufficiently reconstructed in real-time. Secondly, a planning algorithm for the robot to overcome the reconstructed environment is conducted. Based on the reshaped surface, the planning algorithm not only provides the exact body trajectory and foot positions but also the adaptability of the robot in a specific environment. A method to improve the adaptability of the walking and climbing robot is also introduced. Thanks to the adherent ability of the robot, the center of gravity of the robot is allowed to move outside the support polygon to increase the reach-ability of the next swing leg. Finally, the effectiveness of the proposed approach is verified by the performances of the experiments in complex environments using a quadruped walking and climbing robot named MRWALLSPECT IV.     

Optical characteristics of silicon semiconductor bridges under highcurrent density conditions

The optical emission spectra (180-700 nm) of plasma produced by a semiconductor bridge (SCB) with aluminum or tungsten electrodes have been measured and analyzed. The spatially and temporally resolved emission spectra of the SCB device have provided insights into the dynamic discharge of the bridge. The plasma electron temperature of the SCB device was measured using the comparison of the continuum emission of the bridge with the calculated optical emission spectra for a gray body source. Measured electron temperatures in the plasma produced by the bridges are related to the capacitor discharging voltage. The best estimates indicate that 4100-5500 K was measured for Al-electrode SCB device and 5650-6000 K for W-electrode SCB device     

Novel design for high-power single-lateral-mode lasers

A new laser design for single-mode high-power applications is reported. The waveguide is a laterally flaring and transversely tapering GaAs buried ridge fabricated by selective area epitaxy. Single-lateral-mode powers of 200 mW were achieved     

Exercise training, postprandial hypertriglyceridemia, and LDL subfraction distribution

The purpose of this study was to examine differences in postprandial hypertriglyceridemia (PP-HTG) and low density lipoprotein (LDL) subfraction distribution among groups of men and women with different fitness levels. Fifty-four men and women (ages 30-53 yr) were recruited based on their previous two-year activity level: sedentary (S), recreational exercisers (R), and endurance trained (T). After a 24-h dietary preparation, blood was collected, and LDL subfractions were separated and analyzed for cholesterol (C) and apoprotein B100. Plasma triglyceride (TG) concentration was assessed before and at 2, 4, 6, and 8 h after fat meal. PP-HTG was significantly higher for the S group compared with the two activity groups. LDL3-C and LDL3-apoprotein B100 were significantly higher for the S group compared with the T group and for men compared with women. These findings suggest that both recreational and competitive aerobic training are associated with a lower TG response after a fatty meal. However, higher volume aerobic training may be necessary to reduce the number of dense LDL molecules and their cholesterol content.     

Channel width dependence of hot electron injection program/hot hole erase cycling behavior in silicon-oxide-nitride-oxide-silicon (SONOS) memories

The channel width dependence of hot electron injection program/hot hole erase cycling behavior in silicon-oxide-nitride-oxide-silicon (SONOS) memories is investigated. While the trapped charge profile-dependent overerasure is observed in 10-μm-wide device, it is suppressed in 0.22-μm-wide device. Both the overerasure suppression and gradual positive threshold voltage shift in narrow device are explained as an elevated hot hole injection efficiency followed by more pronounced redistribution of the hole profile in the channel-center and the suppression of the lateral migration of injected holes in the channel-edge, by combining the measured endurance characteristics and TCAD simulation results. Main physical mechanisms are three-dimensional distribution of the electric field by gate/drain voltage, increasing interface states, and their trapped charge with cycling in the channel-edge.     

Kinetics of Intermetallic Compound Formation at the Interface Between Sn-3.0Ag-0.5Cu Solder and Cu-Zn Alloy Substrates

The growth kinetics of an intermetallic compound (IMC) layer formed between Sn-3.5Ag-0.5Cu (SAC) solders and Cu-Zn alloy substrates was investigated for samples aged at different temperatures. Scallop-shaped Cu₆Sn₅ formed after soldering by dipping Cu or Cu-10 wt.%Zn wires into the molten solder at 260°C. Isothermal aging was performed at 120°C, 150°C, and 180°C for up to 2000 h. During the aging process, the morphology of Cu₆Sn₅ changed to a planar type in both specimens. Typical bilayer of Cu₆Sn₅ and Cu₃Sn and numerous microvoids were formed at the SAC/Cu interfaces after aging, while Cu₃Sn and microvoids were not observed at the SAC/Cu-Zn interfaces. IMC growth on the Cu substrate was controlled by volume diffusion in all conditions. In contrast, IMC growth on Cu-Zn specimens was controlled by interfacial reaction for a short aging time and volume diffusion kinetics for a long aging time. The growth rate of IMCs on Cu-Zn substrates was much slower due to the larger activation energy and the lower layer growth coefficient for the growth of Cu-Sn IMCs. This effect was more prominent at higher aging temperatures.     

Distribution and removal of added mercury in milk.

Distribution patterns of added mercury in raw whole milk after equilibration for 30 min and 2 h at 37 C showed a distribution among acid casein, whey proteins, fat globule membrane, and soluble fat globule membrane of 33, 28, 16, and 2%. On the basis of protein content, the fat globule membrane had the highest amount of mercury. Mercury added to milk as mercuric chloride was removed by treatment with thiolated aminoethyl celluloses and reduced human hair. In a 5 min treatment, 70, 43, and 41% of the mercury was removed by thiosuccinylated aminoethyl cellulose, thionitrocarboxyphenylated aminoethyl cellulose, and reduced human hair, respectively, from whole milk initially containing 1 ppm mercury and equilibrated for 2 h at 37 C prior to treatment. After treatment for 60 min, 82, 52, and 64% of the mercury was removed by thiosuccinilated aminoethyl cellulose, thionitrocarboxyphenylated aminoethyl cellulose, and reduced hair, respectively. However, increasing incubation temperature and time prior to treatment decreased the removal efficiencies. Thiosuccinilated aminoethyl cellulose and reduced human hair showed increasing efficiency directly with pH, while thionitrocarboxyphenylated aminoethyl cellulose showed the opposite effect and had higher affinity for mercury at pH 5.5 than at pH 7.5. Moreover, the rate of removal of mercury at 4 C compared to 37 C was much slower. The removal of mercury from soluble casein and soluble whey proteins was more efficient than from micellar casein. Protein, lactose content, and pH of milk were not changed by the polymer treatments.     

Effect of material properties of impact limiter steel on drop accident of spent nuclear fuel transport cask

In this study, the sensitivity of the drop response according to changes in material properties was analyzed to determine the material properties that have a dominant influence on energy absorption performance. Parametric analyses were performed using a spent nuclear fuel (SNF) transport cask as an example, wherein the parameters were the material properties related to the stiffness of the steel (the elastic modulus, yield strength, and tangent modulus) that constitutes an impact limiter installed in the SNF transport cask. On the basis of the analysis results, the absorbed impact energy and transmitted energy were quantitatively calculated and the variations in the structural response were identified. In addition, changes in the structural safety of the SNF transport cask were investigated. The results of this study suggest that material properties must be considered to effectively design a structure that absorbs impact energy.