Eletronic publishing and chemical text processing - II. Character and vector representations of chemical structures
Abstract Fragments for two-dimensional chemical structure diagrams can be represented by either characters or vectors. The relative merits of the two approaches are considered and it is shown that the vector representation is clearly superior.
Computer‐Aided Design and Manufacturing (CAD/CAM)
Design has a long history but computer-aided design (CAD) offers a new, modern connotation. With the exception of the physical processes, such as cutting, forging, and mixing used to a manufacture items, the commonly discussed topics in computer-aided manufacturing (CAM), such as material planning, process and procedure designs, numerical control, and scheduling, can also be considered CAD because design is involved. This article reviews the history of computer-aided design beginning with ENIAC, the first electronic computer, which was developed for the army during World War II, through the recent introduction of a computer that has a speed of 100–250 million floating-point operations per second (flops). In automating chemical processes and computations, companies must decide whether to use commercial software packages or to develop in-house CAD/CAM programs. Many of the underlying principles employed in the design of the prevailing commercial software packages are discussed. These principles can also guide the development of in-house programs. The topics covered include absorption to waste management, and range from drafting isometric pipeline systems and the interactive manipulation of block diagrams involved in chemical processes to the solid modeling of molecular structures. 
 
 
Keywords: 
 
Computer application; 
Computer-aided design (CAD); 
Software packages; 
Chemical processing; 
Computer graphics; 
Instruction; 
Chemical structure analysis; 
Pattern recognition; 
Interactive graphics; 
Molecular modeling; 
Process flow sheet; 
Process optimization; 
Process control; 
Modular approach
Phloroglucinol derivatives from Hypericum japonicum.
The isolation and identification of a new phloroglucinol derivative (2), a diterpenol (4), together with the known compounds flavesone (1) and sarothralen B (3), from the aerial parts of Hypericum japonicum are reported. Their structures were established by extensive spectral analysis and the structure of (3) has also been confirmed by a single crystal X-ray determination.