Delay times in Si MOSFETS in the 4.2–400 K temperature range

Temperature dependence of propagation delay time and power-delay product in Si MOSFETs (fabricated using 1 μm X-ray lithography) has been measured using 19-stage ring oscillators. The delay time was found to decrease with lowering temperature. As a numerical example we found that a delay time of 30 ps at room temperature decreased to 22 and 18 ps at 77 and 4.2 K respectively, and increased to 38 at 400 K. The power showed a slight increase with decreasing temperature, while the power-delay product decreased. The decrease in the delay time has been explained in terms of increase in the electron drift velocity with decreasing temperature, as well as decrease in one component of the capacitive load, namely the source-drain junction capacitance, due to carrier freeze-out.     

Optimizing parameters of tuned mass damper subjected to critical earthquake

Tuned mass damper (TMD) has been proposed as one of the vibration control methods for rehabilitation of buildings. Because the parameters of TMD can significantly affect the seismic performance of structures, many researches focused on finding the optimum parameters. Because earthquakes are random phenomena and future earthquakes in comparison with past earthquakes may be more destructive, the optimum design of TMD subjected to selected earthquakes can be nonconservative. Hence, the main contribution of this paper is to present the optimal design of TMD for the seismic vibration control of a structure subjected to a critical earthquake that produces the most severe response of a structure. In order to achieve this purpose, the parameters of TMD are optimized through minimizing the maximum displacement of the roof. First, three optimization methods are used to obtain the optimal parameters of TMD for a 10‐story shear building subjected to the critical earthquakes. Finally, the responses of the controlled and uncontrolled buildings such as the roof displacement, strokes, transfer function, and different forms of energy are compared. Results show that the optimum designs of TMD not only effectively reduce the roof displacement but also improve the seismic performance of the building.     

Passivation of interface-states in large-area Si devices using hydrogen implantation

We have found that in the large-scale transistor structures, where gate oxide thickness of 6 nm and below is used, the standard post-metallization (forming gas) annealing leaves a large number of Si/SiO/sub 2/ interface states unpassivated, with a lower limit of N/sub it/=5e11 cm/sup -2/. This may be due to the limited range of hydrogen (H) diffusion through the thin gate oxide and its ensuing inability to reach beyond the edges of the devices with a channel length larger than 3.0 /spl mu/m. In this study, we have shown that hydrogen ion implantation can successfully remove the residual interface state by placing the hydrogen uniformly throughout the area of a large device. Remarkable improvements in all the device characteristics, including capacitance and current versus voltage and the transistor threshold behavior as a function of the channel length, was achieved by hydrogen implantation and anneal as a final processing step.     

Rural domestic water consumption behavior: A case study in Ramjerd area, Fars province, I.R. Iran

Identifying the factors that affect domestic water demand and consumption is very important in management of available regional water resources. In this study, relationships between water consumption and rural household activities are determined by comparing a snapshot of water consumption with rural household behavior of low, medium and high water consumers. In addition, the factors affecting water consumption in rural households are also determined. The data for this study were collected from a survey of 653 rural households in 33 villages of Ramjerd area, Fars Province, in southern Iran, using a simple random sampling technique. The daily water consumption data for a 5-year period (1999-2004) were used. Results of the study revealed that the daily average water consumption for the area was found to be 121.7 l per person per capita per day (Lpcd) (SD=59.2). Water consumption was also found to be significantly correlated with explanatory variables such as “household size” and “age of household's head”. Finally, the results of discriminant function analysis showed that in rural households, garden size, greenhouse size, and garden watering times per month with tap treated water are associated with water consumption.     

A novel numerical model of debonding of FRP-plated concrete beam

Accurate modeling is required to estimate the debonding in a plated fiber-reinforced polymer (FRP) concrete beam. In the present investigation, a numerical method is developed to model a crack in the FRP–concrete interface. An initial notch is located at the mid-span of the concrete beam. A modified crack closure integral method is implemented to model Mode-I fracture in the concrete. In the present research, a special interface element is formulated to simulate and to predict the distribution of interfacial shear stresses by using drilling degrees of freedom in the nodes of interface elements. Cohesive forces in the nodes of interface elements are formulated by finite element methods. A crack propagation criterion is presented to evaluate when the crack grows in FRP–concrete interface. If the principal stress in the node at the tip of an interface element reaches the maximum shear stress along the FRP–concrete interface, debonding happens. The model is robust, accurate, independent of mesh size, and it is able to model the crack growth in the concrete and debonding of the FRP–concrete interface, simultaneously. The model presented in this study showed acceptable similarity to previous research data.     

The UCR Time Series Archive

The UCR time series archive – introduced in 2002, has become an important resource in the time series data mining community, with at least one thousand published papers making use of at least one data set from the archive. The original incarnation of the archive had sixteen data sets but since that time, it has gone through periodic expansions. The last expansion took place in the summer of 2015 when the archive grew from 45 to 85 data sets. This paper introduces and will focus on the new data expansion from 85 to 128 data sets. Beyond expanding this valuable resource, this paper offers pragmatic advice to anyone who may wish to evaluate a new algorithm on the archive. Finally, this paper makes a novel and yet actionable claim: of the hundreds of papers that show an improvement over the standard baseline (1-nearest neighbor classification), a fraction might be mis-attributing the reasons for their improvement. Moreover, the improvements claimed by these papers might have been achievable with a much simpler modification, requiring just a few lines of code.      

Gate oxide thinning at the active device/FOX boundary insubmicrometer PBL isolation

The impact of several poly buffer LOCOS processing parameters on the integrity and defect density (yield) of the gate oxide has been investigated by correlating electrical and structural studies. We found that a thin PBL pad-oxide, in general, gives rise to higher defect density. In addition, it results in a sharp active device/field oxide (FOX) boundary which, by the process of screen oxide growth and etch-back and FOX pull-back, creates a step in the Si in the bird's beak region. TEM studies revealed gate oxide thinning by as much as 30% over this step, explaining the early gate oxide breakdown at the active device/FOX region