Electron Density and Optical Emission Measurements of SF6/O2 Plasmas for Silicon Etch Processes

This work investigates internal plasma process parameters using a hairpin resonance probe and optical emission spectroscopy. The dependence of electron density and atomic fluorine on the percentage of oxygen in an SF6 /O2 discharge was measured using these methods. An RIE Oxford Instruments 80 plus chamber was used for the experiments. Two different process powers (100 W and 300 W) at a constant pressure (100 mTorr) were used, and it was found that the optical emission intensity of the 703.7 nm and 685.6 nm lines of atomic fluorine increased rapidly as oxygen was added to the SF6 discharge, reached their maximum at an O2 fraction of 20% and then decreased with further addition of oxygen. The plasma electron density was also strongly influenced by the addition of O2 .     

Improved spatial resolution in soil moisture retrieval at arid mining area using apparent thermal inertia

A surface soil moisture model with improved spatial resolution was developed using remotely sensed apparent thermal inertia (ATI). The model integrates the surface temperature derived from TM/ETM+ image and the mean surface temperature from MODIS images to improve the spatial resolution of soil temperature difference based on the heat conduction equation, which is necessary to calculate the ATI. Consequently, the spatial resolution of ATI and SMC can be enhanced from 1 km to 120 m (TM) or 60 m (ETM+). Moreover, the enhanced ATI has a much stronger correlation coefficient (R²) with SMC (0.789) than the surface reflectance (0.108) or the ATI derived only from MODIS images (0.264). Based on the regression statistics of the field SMC measurement and enhanced ATI, a linear regression model with an RMS error of 1.90% was found.     

Observations on Normal Grain Growth of Magnesia and Calcia

It is generally agreed that the rate of grain growth in metallic systems may be expressed by an equation that describes the square of the average diameter as being proportional to the time of annealing at constant temperature. The proportionality constant is exponentially dependent on temperature as normally expected in a rate expression according to the theory of reaction kinetics. The purpose of this study was to check the applicability of these equations to metallic oxide systems. Reagent-grade MgO and CaO prepared from reagent-grade CaCl₂ obeyed the grain-growth expressions reasonably well. Strong temperature dependence of the growth rate of both materials was attributed to impurities. Activation energies of 110 and 60 kcal per mole were calculated for CaO and MgO, respectively. Both values are higher than would be anticipated for grain-boundary diffusion in high-purity materials. Although porosity varied considerably for various isotherms, no effect of porosity on grain growth was detected. The data, however, were considered to be insufficient to warrant strong conclusions concerning this variable.     

Effects of Long-Grain Rough Rice Storage History on End-Use Quality

Rough rice (cv. Cypress) from the 1995 season was harvested, dried, and stored in laboratory-scale studies. Treatments included pre-drying conditions, drying conditions, storage temperatures, and storage durations. Temporary wet storage prior to drying affected cooking properties (p<0.005) and peak viscosity (p<0.005). Drying treatments affected head rice yield (p<0.05), cooking properties (p<0.001), and peak viscosity (p<0.05). Storage temperature was related (p<0.05) to cooking properties and peak viscosity via a second-order relationship. Head rice yield and cooking properties were also affected (p<0.05) by storage duration.     

β-Robust scheduling for single-machine systems with uncertain processing times

In scheduling environments with processing time uncertainty, system performance is determined by both the sequence in which jobs are ordered and the actual processing times of jobs. For these situations, the risk of achieving substandard system performance can be an important measure of scheduling effectiveness. To hedge this risk requires an explicit consideration of both the mean and the variance of system performance associated with alternative schedules, and motivates a β-robustness objective to capture the likelihood that a schedule yields actual performance no worse than a given target level. In this paper we focus on β-robust scheduling issues in single-stage production environments with uncertain processing times. We define a general β-robust scheduling objective, formulate the β-robust scheduling problem that results when job processing times are independent random variables and the performance measure of interest is the total flow time across all jobs, establish problem complexity, and develop exact and heuristic solution approaches. We then extend the 0-robust scheduling model to consider situations where the uncertainty associated with individual job processing times can be selectively controlled through resource allocation. Computational results are reported to demonstrate the efficiency and effectiveness of the solution procedures.     

Effects of Carbonic Acid Dips and Packaging Films on the Shelflife of Fresh Fish Fillets

Carbonic acid and semi-permeable packaging materials were investigated for their effect on shelflife of fresh fish. Cod fillets (Gadus morhua) were dipped in carbonic acid and then stored packaged and unpackaged at 2°C. Samples were evaluated for weight loss, surface pH, texture changes, surface microbial growth, headspace gas composition, and sensory characteristics of cooked flavor, odor, and appearance. Carbonic acid was capable of extending shelflife between 7 and 21 days; however, only at a quality level judged as fair to marginal by sensory evaluations. Low permeability packaging slowed bacterial growth and extended shelflife, but retained off-odors and established low oxygen conditions which may present a risk from the growth of pathogenic organisms.     

Spatio-temporal variation of vegetation in an arid and vulnerable coal mining region

Environmental assessment in an arid coal mining area requires an understanding of the influences of coal mining,the arid climate and ecological remediation.To that end,we selected vegetation as the key environmental factor to observe.Remote sensing approaches to monitoring the spatio-temporal variation of vegetation caused by mining activities,the arid climate and ecological remediation in the Shengdong coal mining area are described.Over a large regional scale it was found that the vegetation was improved as a result of ecological remediation activities.At the local scale,however,the vegetation coverage and soil moisture in the mined areas were slightly lower than those in un-mined areas due to mining subsidence.These differences are partly attributed to ground fissures that injure root systems and increase the depletion of soil moisture.It is recommended that fissures be reduced and filled to lessen their adverse effects on the environment.