Caulerpin (1a), a bis-indole alkaloid from the marine algal Caulerpa sp., was synthesized in three reaction steps with an overall yield of 11%. The caulerpin analogues (1b-1g) were prepared using the same synthetic pathway with overall yields between 3% and 8%. The key reaction involved a radical oxidative aromatic substitution involving xanthate (3) and 3-formylindole compounds (4a-4g). All bi...

Multistage collectors are commonly used in travelling wave tubes (TWTs), klystrons, gyrotrons and inductive output tubes (IOTs). A dc beam transfers some of its energy to the input RF wave during its travel through the interaction circuit. The purpose of a collector is to recover most of the remaining dc power from the spent beam and thereby increase both the collector and the overall efficienc...

An evacuated tube solar collector using therminol D-12 as heat transfer fluid coupled with parabolic trough is studied in this paper. An experimental set-up was constructed to study the performance of evacuated tube collector with therminol D-12 as heat transfer fluid. The parabolic trough is coupled with evacuated tube collector for better performance. In the traditional solar collectors water...

We have demonstrated a heterojunction bipolar transistor using a novel compound collector (CCHBT) design that allows a low-knee voltage and high-breakdown voltage to be obtained simultaneously. The novel aspect of this design is to use a short wide band-gap collector only over a narrow portion of the collector, where the field is highest. This allows support of high fields while maintaining a l...

A copying collector has two excellent properties: it compacts the heap, and the execution time depends solely on the number of live objects. Use of a copying collector is thought by some to be a more efficient way of managing the heap than explicit freeing of objects. This paper describes a high-performance copying collector for a hybrid object-oriented language. The collector is both conservat...

Our research is concerned with compiler-independent, tag-free garbage collection for the C ++ programming language. This paper presents a mark-and-sweep collector , and explains how it ameliorates shortcomings of a previous copy collector. The new collector, like the old, uses C ++ 's facilities for creating abstract data types to deene a tracked reference type, called roots, at the level of th...

The realization of collector-up light-emitting complementary charge injection transistors is reported. The devices have been implemented in molecular-beam-epitaxy-grown n-InGaAs/ InAlAs/p-InGaAs and n-InGaAs/InP/p-InGaAs heterostructures using a self-aligned process for the collector stripe definition. Electrons, injected over the wide-gap heterostructure barrier (InAlAs or InP) by the real-spa...

In this paper we present a prototype for a new type of solar thermal collector designed for architectural integration. In this proposal, the conventional geometry of a flat solar thermal collector is changed to a curved geometry, to improve its visual impact when mounted on a building facade or roof. The mathematical equations for the beam and diffuse solar radiation received by a collector wit...

Generational garbage collection is an established method for creating eecient garbage collectors. Even a simple implementation where all nodes that survive one garbage collection are tenured, i.e., moved to an old generation, works well in strict languages. In a lazy language, however, such an implementation can create severe temporary space leaks. The temporary space leaks appear in programs t...

The effect of the volume flow rate of the heat transfer fluid (air) on the thermal parameters of the solar air collector with a single air pass without using fins under the absorbing plate have been investigated experimentally and theoretically. We use a new design of solar air collector which aims to optimize these parameters in the region cited above. Our solar air collector was realized at t...