Growth of a single-wall carbon nanotube film and its patterning as an n-type field effect transistor device using an integrated circuit compatible process

This study presents the synthesis of a dense single-wall carbon nanotube (SWNT) network on a silicon substrate using alcohol as the source gas. The nanosize catalysts required are made by the reduction of metal compounds in ethanol. The key point in spreading the nanoparticles on the substrate, so that the SWNT network can be grown over the entire wafer, is making the substrate surface hydrophilic. This SWNT network is so dense that it can be treated like a thin film. Methods of patterning this SWNT film with integrated circuit compatible processes are presented and discussed for the first time in the literature. Finally, fabrication and characteristic measurements of a field effect transistor (FET) using this SWNT film are also demonstrated. This FET is shown to have better electronic properties than any other kind of thin film transistor. This thin film with good electronic properties can be readily applied in the processing of many other SWNT electronic devices.     

The effects of dental condition on hand strength and maximum bite force

Piezoelectric force transducer and hand dynamometer were used for measuring the maximum bite force and hand grasp force on 2034 primary, middle, and high school students. Dental condition and body weight and height were also observed to relate to the force measurements. It was discovered that both forces increased relative to the increase of age, body weight, and body height. Boys had stronger bite force than girls at all age groups, while the grasp force of boys became significantly stronger only after the age of 13. Students who had dentition with decay and missing teeth tended to have weaker bite force, while hand force was not influenced. Bite force does not seem parallel to hand strength and is, instead, related to dental condition.     

Absence seizures as resetting mechanisms of brain dynamics

To understand the increase in age-related incidence and frequency of absence seizures in the rat brain, we investigated the effect of these seizures on brain dynamics. This paper puts forward the hypothesis that age-related differences in the expression of absence seizures are associated with the ability of the seizures to reset brain dynamics. This work was supported by an Epilepsy Foundation Targeted Research Initiative for Seniors Award (SPN), NINDS 5R01-NS046015 (KMK), and NIBIB R01EB002089 (JCS). __________ Translated from Kibernetika i Sistemnyi Analiz, No. 5, pp. 45–53, September–October 2008. An erratum to this article can be found at     

Kinetic Model for Oxidative Dehydrogenation of n-Butanol over Copper-Barium Catalyst

Kinetics for oxidative dehydrogenation of n-butanol over copper-barium catalyst was investigated in a fixed-bed reactor. The effects of oxygen addition, temperature, initial partial pressure, and time factor on the conversion were studied. The results show that the catalyst is quite active and selective for the dehydrogenation of n-butanol and will become more active when a small amount of oxygen is added in the feed stream. A partial redox model including a pair of redox reaction steps parallel with a direct dehydrogenation reaction step was developed. The rate constants for the three reaction steps were evaluated. The model can predict the experimental data quite well, with a standard deviation less than ±5%.     

Clustering Quantile Regression-Based Drought Trends in Taiwan

Drought is a normal, recurring climatic feature and occurs in all climatic zones. Imbalanced water availability induced by droughts has far-reaching and adverse impacts both on human lives and natural environments. This study aims to summarize temporal and spatial drought variations in Taiwan by combining quantile regression and cluster analysis. Three-monthly rainfall series covering the 1947–2012 period for 12 rainfall stations are used in this study. Quantile regression is applied to 3-month SPI, drought duration, drought severity, and drought frequency series for exploring temporal drought trends at different quantiles. Various quantile slopes for these 12 stations are then analyzed by hierarchical agglomerative clustering algorithm to detect regional variation patterns. The results show considerable spatial diversity over Taiwan. Stations along east coast are prone to more severity due to declined SPI trends associated with increasing drought duration and severity. Positive SPI slope associated with decreasing drought duration and severity are noted at stations located in the west and lead to lessened droughts. However, temporal variations in drought-duration and drought-severity series are insignificant at most quantiles and stations. In addition, a distinct behavior is found in drought frequency since severe droughts may not accompany frequent droughts.     

Critical speed analysis for nonlinear effects of rotor system and ball end milling

The critical speed analysis for nonlinear effects of rotor-bearing system and ball end milling are studied in this paper. The nonlinear cutting force can be calculated by using the Tlusty proposed 3/4 rule for chip thickness. The rotor system is supported by bearings with nonlinear spring effects. The critical speeds obtained from this study are compared with two sets of experimental data to validate the proposed four cases. The effects of design parameters on system dynamic behaviors, including critical speeds and tool displacements under the dynamic cutting forces, are numerically investigated in the time domain. The results show that the critical speeds of system are proportional to the corresponding system natural frequencies, but inversely to the cycle number of tool vibration multiplying by the number of flutes during the cutting time from one flute to another. For the linear system and the nonlinear system with small depth-of-cut under linear cutting force milling, their critical speeds are almost identical. With large feed-per-tooth, the differences of the critical speeds become larger between linear and nonlinear rotor systems and so are the dynamic responses at critical speeds milling. The critical speed under nonlinear cutting force milling is found to be always higher than that under linear cutting force. Furthermore, the chatter stability lobes are studied for various cutting conditions. The intervals between critical speeds increase gradually, and the axial depths of cut of nonlinear system for stability are lower than those of linear system.     

Scheduling deteriorating jobs to minimize the makespan on a single machine

Machine scheduling problems with deteriorating jobs have received increasing attention in recent years, mostly focusing on the linear deterioration models. However, if certain maintenance procedures fail to be completed prior to a prespecified deadline, jobs will require extra time for successful accomplishment in some situations. Therefore, this paper addresses a single-machine problem where the objective is to minimize the makespan under the piecewise linear deterioration model. A branch-and-bound algorithm and two heuristic algorithms are provided to search for the optimal solution and near-optimal solutions, respectively. Computational results are also presented to evaluate the performance of the proposed algorithms.     

Repeatability/Linearity Study and Measurement Loss Cost Analysis of an Automatic Gauge

Computer-aided inspection (CAI) has become one of the fundamental steps in advanced manufacturing by employing automatic gauges. However, it is necessary to provide a more practical way to evaluate CAI on-line efficiency. Since a gauge capability study should be conducted before applying any automatic gauge, the necessary off-line gauge assesment for CAI is introduced in this paper. An R&R (repeatability/reproducibility) study is commonly conducted in the gauge capability study, but in this paper, an R&L (repeatability/linearity) study of a machine vision system is investigated and introduced. The ANOVA approach and regression approach are applied and compared to study the linearity effect. The measurement loss cost includes extra costs (i.e. costs of discarding, reworking, inspection, and quality loss) that arise from measurement error. These costs are analysed by interpreting the relationships between manufacturing capability, gauge capability, and the tolerance. As most gauge capability studies were conducted for the bilateral tolerance inspection, unbalanced tolerance inspection is considered here. The way that the relative costs contribute to the measurement loss cost is also studied. Rather than using a constant measurement error determined by previous observations, the measurement error model is embedded in the relative cost models. Users can then evaluate CAI on-line efficiency by incorporating the measurement error when the tolerances are rapidly changed to satisfy customer requirements.     

Factors affecting online group buying intention and satisfaction: A social exchange theory perspective

This study investigates factors that affect consumer continuous use intention toward online group buying and the degree that reciprocity and reputation of social exchange, trust, and vendor creativity affect consumer satisfaction and intention toward online purchasing. Data from 215 valid samples was obtained using an online survey. The research model is assessed using partial least squares (PLS) analysis. The results show that the intention to engage in online group buying is predicted collectively by consumer satisfaction, trust, and seller creativity. Consumer satisfaction with online group buying is predicted primarily by trust, followed by consumer reciprocity. The proposed research model explains 67.7% of variance for satisfaction and 39.7% of variance for intention to engage in online group buying. The results suggest that reciprocity, trust, satisfaction, and seller creativity provide considerable explanatory power for intention to engage in online group buying behavior.