Logical connector

Dropping R groups. An additional option, used by the Chemical Abstracts Service, is simply to replace an overlapping substituent by a letter R, called a logical connector, and display the substituent in a legend elsewhere on the computer screen (Figure 44). ... 

Figure 44 Avoiding atom overlap with a logical connector.

Overlap prevention and repair heuristics. Although bond stretching has been used from the start, Shelley revolutionized the area with both prophylactic and post-facto techniques that remain the best available. The CAS alone employs logical connectors to remove offending groups (Figure 44). 

Logical Components, connectors How business logic is logically partitioned in software how parts collaborate... 

In order to carry out sophisticated computation the molecular computers of tomorrow will need not just basic elements such as switches, memory and connectors but also more sophisticated components, particularly logic gates. A logic gate is an element of a computer that gives a particular output for a... 

Extraction cells Different cell types are available, but the best choice is cells that can be sealed properly without any tools. In commercial systems hand-tightened extraction cells are standard. Cells are available in sizes from 1 to 100 ml. The material in the cells should be inert and should not absorb the extracting media. Stainless steel or crystalline polymers are common materials for this purpose. There have been discussions on the orientation of the extraction cells, but the most logical way is a vertical position with the fluid entering from the top. This means that there is no delay in emergence of the extracted analytes. Solid matrices should be uniformly packed into the cell, with no easy passages for the fluid. Care must be taken when assembling the cell to keep particles away from the surfaces of the connectors. 

It has unacceptable connector loss if star or bus logical topologies are required. Connectors are located throughout system, making administration and rearrangement difficult. 

The HV cut-out cable - this is a logic level and the specification of the cable is not critical. It wiU need BNC connectors. 

Digital components often have large numbers of leads, as high as 400 or more. This high lead count stems from logic architectures that have data and address buses as wide as 128 bits or more. To connect PCBs with these wide data buses, digital systems often contain board-to-board connectors with as many as 1,000 pins. 

The parallel port/printer adapter in a PC was previously intended to connect printers to computers. However, it was also used for connecting other devices to PCs. The printer adapter has three independent transistor-transistor logic (TTL) compatible ports an 8-bit output-data port, a 4-bit output-control port with open-collector drivers, and a 5-bit input-status port. The two output ports also have input registers at identical addresses. Writing to the data register causes the byte sent to be latched and to appear on the parallel port s 25-pin D-type connector. Reading this register returns the contents of the latch. Parallel ports have also been extensively used in measurement applications. The main... 

To avoid confusion, it is best to use charts to show the status of the seven pins. For example, use NEC for negative, POS for positive. Inactive pins that illuminate neither LED should not be left blank - otherwise you may not know if you have already tested the pin. Instead, use an X to represent any undefined logic state. Beside each number Is the abbreviation of Its name as well as an 0 for output and I for Input. When the connector is charted, you ll have a good idea of what control logic is being used. Two examples, one for a DTE and one for a DCE, are given. 

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