Synthesis of 1,4-Phenanthrenequinones via Stannic Chloride-Induced Cyclizations

Substituted 1,4-phenanthrenequinones such as 1 are useful building blocks for the preparation of novel materials. Katz and others have shown that compounds such as 1 can be transformed into helicenes by DielsAlder reactions.1 Certain 1,4-phenanthrenequinones also have potential as synthetic intermediates for natural products synthesis. Additionally, some naturally occurring 1,4-phenanthrenequinones such as cypripedium (2) are biologically active.2 Kraus and Carpenter have determined that some 1,4-phenanthrenequinones exhibit inhibitory activity in vitro against the equine infectious anemia virus.

Terahertz Radiation of a Low-inductance Discharge in Vacuum with Laser-plasma Initiation

The results of the study of terahertz radiation, which is generated by the plasma of a low-inductance discharge with micropinchs, are presented in this paper. The discharge was initiated by focused radiation from a pulsed Nd:YAG laser (pulse duration is 10 ns, pulse energy is 0.8 J). The energy that was stored in the capacitor of the discharge system was ∼ 40 J. The principal role of micropinch for the generation of THz radiation was proposed. The oscillogram of the diode current was obtained to visualize the presence of micropinch plasma. The power of the THz source was calculated and an experimental study of the spectrum of this source was carried out

Laser-based Diagnostics for Use in Ex-situ Lithium Co-deposit Analysis

Laser-induced breakdown spectroscopy (LIBS) and time of flight (TOF) mass spectrometry of laser-produced ions were tested for ex-situ analysis of lithium co-deposited layers produced by plasma deposition. It was found that LIBS provides an adequate way to observe and measure lithium content in thin co-deposited layers of about 1 µm thickness. TOF mass spectrometry data of the same layers was compared with LIBS. TOF mass spectrometry provided a better resolution; however, the simplicity of LIBS setup and the rate of measurement (less than one minute per measurement) makes it more attractive. Argon was observed in the co-deposited layers, indicating that it, and likely other inert gases, can remain trapped in lithium layers even after a prolonged exposure to and chemical reaction with atmospheric air