Biology 代写 An Introduction To Nanoscience And Nanotechnology
The word nanotechnology is an umbrella term and it accommodates conventional physics, biology, chemistry, materials science and full range of engineering disciplines. Nanotechnology is an entirely new concept in manufacturing that will make most products lighter, stronger, cleaner, less expensive and more precise. Nanotechnology will profoundly affect economy and society, much as the industrial revolution has. Over the past few years, we have witnessed rapid advances in the field of nanotechnology on many fronts including materials and manufacturing, nano-electronics, medicine and healthcare, energy, biotechnology and information technology. These advances have led to the availability of an array of technologies for potential applications. Applications of nanotechnology during the next few decades could produce huge increase in computer speed and storage capacity, efficient lighting and battery storage, reduction in the cost of desalinating water, clothes that never stain and glass that never needs cleaning and therapies for different types of ailments.
Technology in the twenty first century demands the miniaturization of devices into nanometer sizes while their performance is amazingly enhanced. It is widely felt that nanotechnology will be the next industrial revolution. The nanotechnology products, materials and their applications are still in developing stage and true revolution is years away, it can be a few or many years. This technology aims tinier and faster instead of bigger and slower. Thus, nanotechnology provides access to the world of the smallest things. While the benefits are almost limitless, they will be realized only if the adverse effects of nanotechnology are studied and managed.
1.1 Definition
The "nano" in nanotechnology comes from the Greek word "nanos" which means dwarf, refers to a reduction of size by 10-9 m. A nanometer (nm) equals 10-9 meter. To create a sense of nano scaled objects, one human hair is about 80,000 nanometers thick; a head of a pin is about a million nanometers wide; an atom is about 1 nm wide; a DNA molecule is about 2.5 nm wide and a red blood cell is about 5,000 nm in diameter. A nanoelement can be compared to a basketball, like a basketball to the size of the earth. Figure 1.1 illustrates the differences in scale that ranges from human all the way down to one atom. The figure also shows appropriate tools and models for the study of objects at various sizes. Atoms are the building blocks of materials and the properties of the materials can be tuned by the arrangement of atoms. Only through the use of powerful microscopes, scientists can 'see' and manipulate nano-sized particles. It is appropriate to name the nanometer scale 'the Feynman (φ nman) scale' after Feynman's great contributions to nanotechnology.
1 Feynman [φ] = 1 Nanometer [nm] = 10-9 meter =10-3 Micron [μ] =10 Angstroms [Å]
Nanoscience involves researches to discover new behaviours and properties of materials with dimensions at nanoscale, which ranges roughly from 1 to 100 nanometers. Nanotechnology is the research and development of materials, devices and systems by controlling shape and size at the nanometer scale with at least one novel property. The United States National Science Foundation [NSF] defines nanoscience or nanotechnology as studies that deal with materials and systems having the following key properties: (i) Dimension - at least one dimension from 1 to 100 nanometers, (ii) Process - designed with methodologies that shows fundamental control over the physical and chemical attributes of molecular-scale structures, and (iii) Building block property - they can be combined to form larger structures. The national nanotechnology initiative of NSF defines nanotechnology as 'the understanding and control of matter at dimensions of roughly 1 to 100 nanometers, where unique phenomena enable novel applications'. In short, nanotechnology is the ability to build micro and macro materials and products with atomic precision.
