Principle Chromatographic procedures allow a separation of substance mixtures with the aid of a stationary separating phase and a mobile phase. In gas chromatography the mobile phase is a gas. The mobile phase, to which the mixture to be separated is added, transports the substance mixture through the separation column at a constant flow rate. Interactions occur between the mobile phase and the...

The fabrication and performance of an ultra-thin-film integrated gas sensor for detecting impurities in semiconductor process gases are described. Detector responses are based on gas-induced resistance changes in an ultra-thin Ti-P film mounted on a thin dielectric window supported by a silicon rim. The window temperature can be shifted several hundred degrees Celsius in less than one second. G...

Suppressed ion chromatography with a conductivity detector was developed for the determination of trace amounts of underivatized chloroacetic acids (CAAs). When sodium carbonate and methanol were used as a mobile phase, the simultaneous determination of each CAA took approximately 25 min. The linearity, reproducibility and detection limits were determined for the proposed method. For the solid-...

Biodiesel has become an attractive fuel recently, because it is renewable, non-toxic, biodegradable, environmentally friendly, etc. With the increase in the production of biodiesel, the problem of disposing crude glycerol, which is produced as main by-product from biodiesel process such as transesterification, has been raised. Therefore, we have been developing a new green technology-Hydrotherm...

Terahertz (THz) imaging can see through otherwise opaque materials. However, because of the long wavelengths of THz radiation (λ = 400 μm at 0.75 THz), far-field THz imaging techniques suffer from low resolution compared to visible wavelengths. We demonstrate noninvasive, near-field THz imaging with subwavelength resolution. We project a time-varying, intense (>100 μJ/cm(2)) optical pattern ont...

Key Laboratory of Modern Precision Agriculture System Integration Research, Ministry of Education, China Agricultural University, Beijing 100083, China. *Email: [email protected] ABSTRACT: The soil electrical conductivity (EC) refers to the capability for soil to conduct current. It is a comprehensive reflection of soil salinity and moisture. Therefore, acquiring soil EC rapidly and accurately ca...

An attempt has been made to study the impact of calcium carbonate on soil dielectric properties. The dielectric constant (ε') and dielectric loss (ε'') of soil with increasing percentage of calcium carbonate are measured at 7.0 GHz. These measurements are carried at room temperature. The J-band microwave setup with slotted section and a crystal detector is used for measurements. The two point m...

New data regarding performance studies of Frisch-grid CdZnTe (CZT) detectors are presented. The Frisch-grid detector configuration under investigation is a bar shaped CZT crystal with the side surfaces coated with an insulating layer. A Frisch grid is fashioned by inserting the CZT bar into a metallic sleeve, or by depositing the metal directly upon the insulator; hence the semiconductor materi...

Detection of explosives has the flavor of those mathematical problems that are not invertible. It is easier to hide explosives than to find them. Many approaches have been proposed and executed for the remote detection of explosives, contraband materials, weapons of mass destruction, currency, etc. Most detection technologies suffer from a common problem: the features they look for, such as dis...