Antitumor activity of SRI 62-834, a cyclic ether analog of ET-18-OCH3

SRI 62-834, an analog of the antitumor agent ET-18-OCH₃ in which the oxygen atom at carbon atom 2 has been incorporated into a five-membered heterocycle, has been prepared and evaluated as an antitumor agent. The compound exhibited good cytotoxicity in vitro against a variety of tumor cell lines and was as effective as ET-18-OCH₃ given orally in the mouse Meth A sarcoma model. SRI 62-834 was shown to be an inhibitor of platelet-derived growth factor (PDGF), possibly at the receptor level, and platelet-activating factor (PAF) at the receptor level.     

Hemt’s capability for millimeter wave applications

This paper presents a tutorial review on the High Electron Mobility Transistors (HEMTs)for low-noise and power applications at millimeter wave range frequencies. The major parameters to achieve high performance with such devices are discussed. Present status on power and noise performances is given for InAlAs/InGaAs HEMTs on InP and GaAs substrates.     

Structural and quantitative evolution of organic matters in oil shale during two different retorting processes

In this study, traditional strongly endothermic anaerobic retorting (AR) and relatively novel self-heating retorting (SHR) processes for oil shale (OS) were investigated and compared in detail. These studies mainly involve the structural and quantitative evolution of organic matters in OS during retorting, including varieties of crystallite parameters, carbon framework structure, amounts of various structural carbons and toxic polycyclic aromatic hydrocarbons, and so on. The obtained results well elucidate some reaction pathways in AR and SHR as well as certain differences between the two retorting processes. Moreover, based on our former work that verifies SHR greatly simplifies retorting operation by in situ generating heat to replace external heat carrier/provision, this study further demonstrates that SHR also alleviates the environmental effect of organic toxic residues as compared to AR. The present study provides some critical results not only for penetrating the reaction mechanism but also for assessing or controlling the environmental impact of both retorting processes.     

A new method for on wafer noise measurement

A method for measuring the noise parameters of MESFETs and HEMTs is presented. It is based on the fact that three independent noise parameters are sufficient to fully describe the device noise performance. It is shown that two noise parameters, R_n and |Y_OPT|, can be directly obtained from the frequency variation of the noise figure F₅₀ corresponding to a 50 Ω generator impedance. By using a theoretical relation between the intrinsic noise sources as additional data, the F₅₀ measurement only can provide the four noise parameters. A good agreement with more conventional techniques is obtained