Replacing COPPER conductors with NANOTUBES

The life of the silicon chip industry

components to silicon chips to increase computer capability. Because copper’s
resistance to electricity increases greatly as the metal’s dimensions decreases there is a limit to how small copper conductors can be.
In contrast, extremely tiny carbon nanotubes can substitute for copper conductors in smaller computer chip electronic configurations because carbon nanotube electrical resistance is not high.
The new process includes ‘growing’ microscopic, whisker-like carbon nanotubes on the surface of a silicon wafer by means of a chemical process. Researchers deposit a layer of silica over the nanotubes grown on the chip to fill the spaces between the tubes. Then the surface is polished flat.Scientists can build more multiple, cake-like layers with vertical carbon nanotube ‘wires’ that can interconnect layers of electronics that made up the chip

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Introduction to CDMA

Cellular networks are wireless WANs that establish a connections between cellular users. The cellular network is comprised of many "cells". The users communicate within a cell through wireless communications. A Base Transceiver Station (BTS) is used by the mobile units in each cell by using wireless communications. One BTS is assigned to each cell. Regular cable communication channels can be used to connect the BTSs to the Mobile Switching Center (MSC). The MSC determines the destination of the call received from a BTS and routes it to a proper destination either by sending it to another BTS or to a regular telephone network. Keep in mind that the communications is wireless within a cell only.
The words "code" and "division" are important parts of how CDMA works. CDMA uses codes to convert between analog voice signals and digital signals. CDMA also uses codes to separate (or divide) voice and control data into data streams called "channels." These digital data stream channels should not be confused with frequency channels.

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CODE DIVISION MULTIPLE ACCESS (CDMA)

The current cellular networks use many different, in compatible standards which relay on different frequency modulation techniques. The focus of the third generation wireless systems is on a predominantly analog because mobile communications have been primarily developed for voice users. How ever the use of cellular networks to support mobile communicating applications is increasing rapidly due to the emphasis on mobile commerce.

A collection of technologies are emerging to provide analog as well as digital services over cellular networks to support mobile users and applications. The cellular networks are evolving through first, second and third generations. The technology CDMA belongs to third generation of cellular networks.

This is an attempt to give you clear idea on “how to generate a CDMA signal” and “what are the stages involved to generate a CDMA signal”. It also includes “what are the call processing stages”.

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Worldwide Interoperability for Microwave Access(Wi-MAX)

The two driving forces of modern Internet are broadband, and wireless. The WiMax standard combines the two, delivering high-speed broadband Internet access over a wireless connection. The main problems with broadband access are that it is pretty expensive and it doesn't reach all areas. The main problem with WiFi access is that hot spots are very small, so coverage is sparse.

Wi-MAX is short for Worldwide Interoperability for Microwave Access, and it also goes by the IEEE name 802.16. WiMAX has the potential to do to broadband Internet access what cell phones have done to phone access. In the same way that many people have given up their "land lines" in favor of cell phones, WiMAX could replace cable and DSL services, providing universal Internet access just about anywhere you go. Wi-MAX delivers a point-to-multi point architecture, making it an ideal method for carriers to deliver broadband to locations where wired connections would be difficult or costly. It may also provide a useful solution for delivering broadband to rural areas where high-speed lines have not yet become available. A WiMax connection can also be bridged or routed to a standard wired or wireless Local Area Network (LAN).

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NANOTECHNOLOGY

Nanotechnology is molecular manufacturing or, more simply building things one atom or molecule at a time with programmed nanoscopic robot arms. A nanometer is one billionth of a meter (3 to 4 atoms wide). Utilizing the well-understood chemical properties of atoms and molecules (how they stick together) a nanotechnology proposes the construction of novel molecular devices possessing extraordinary properties. The trick is to manipulate atoms individually and place them exactly where needed to produce the desired structure.

Nanotechnology broadly refers to the manipulation of matter on the atomic and molecular scales i.e. where the objects of interest are 0.1-100 nanometer n size. Atomic diameters represent the lower end of this range at tenths of nanometers. Transistors used in the present generation of microprocessors, with dimensions of the order of 100 nanometers are at the upper end of the nanotechnology range. As atoms come together to form molecules and molecules come together to form clusters or crystals, the inherent macro-scale properties are determined. By controlling molecular structure in material synthesis, mankind has gained unprecedented control over the basic material properties such as conductivity, strength, capacity, ductility and reactivity, yielding innovative applications ranging from batteries to automotive materials. This is a passive nano technique that primarily focuses on tuning the properties of resulting bulk materials. The active nano technique facilitates creation of functional electronic and ultimately mechanical devices at the nano scale.

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NANOTECHNOLOGY, A BREAK THROUGH IN ALL FIELDS

Nanotechnology has been successful in almost all the fields irrespective of its kind and with the help of this technology it is possible to perform any type of operations starting from manipulating the molecules for separating impurities to the stage where it is the easy method for the production of power.In molecular manufacturing systems, using nanotechnology it is possible transform raw materials, in molecular form, into finished products. Impurities could be separated from feedstock molecules using a sorting rotor .
The purified molecules can be transported away from the sorter system using the molecular equivalent of a conveyor belt. Once a conveyor belt, the molecules can be transported to other belts, changing speed or frequency if necessary. The estimated belt speed is 0.5cm/s and the transition time form belt to belt is less than 0.2µs. a system for transforming a stream of small feedstock molecules into a stream of reagent moieties would be between one million and three million atoms in size. It could deliver the equivalent of its own mass is about 3 sec. The error is rated to be less than 1in 1015 operations at 106 operations per second. This gives a mean time to failure of about 3000 years. Other possible scheme has reagent moieties transported up through the centre of a hollow manipulator arm to a working tip for positional synthesis.

Nano technology is also playing an important role for electronic displays so as replace existing CRO and CRT’s and it is even competing with LCD (Liquid Crystal Display) which is the advanced trend in electronic displays.
The process involved for electronic display using nanotubes is as follows:
• Firstly, Mixture of C60 and nickel is ‘steered’ to specific surface sites by evaporating through a mask. The mask has an array of holes of 300 nm and can be moved with a precision of 1 nm.
• The C60/nickel mixture is evaporated sequentially in ultra high vacuum so as to form alternating layers of C60 and nickel with no impurities
• Then heat it up in the presence of a magnetic field. In this step, the C60 molecules are transformed into bundles of perfectly aligned nanotubes.

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Micro Electro Mechanical Systems

Micro-Electro-Mechanical Systems (MEMS) is the integration of mechanical elements, sensors, actuators, and electronics on a common silicon substrate through micro fabrication technology. While the electronics are fabricated using integrated circuit (IC) process sequences (e.g., CMOS, Bipolar, or BICMOS processes), the micro mechanical components are fabricated using compatible “micro machining” processes that selectively etch away parts of the silicon wafer or add new structural layers to form the mechanical and electromechanical devices.
MEMS promises to revolutionize nearly every product category by bringing together silicon-based microelectronics with micro machining technology, making possible the realization of complete systems-on-a-chip. MEMS is an enabling technology allowing the development of smart products, augmenting the computational ability of microelectronics with the perception and control capabilities of micro sensors and micro actuators and expanding the space of possible designs and applications.

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