"नैनोप्रौद्योगिकी": अवतरणों में अंतर
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Sanjeev bot (वार्ता | योगदान) छो बॉट: वर्तनी एकरूपता। |
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पंक्ति 29:
* सबसे छोटी [[कोशिका|कोशिकाएं]], [[मैकोप्लास्मा|<span title="Mycoplasma">मैकोप्लास्मा</span>]] [[जाति|<span title="Genus">जाति</span>]] के [[जीवाणु|<span title="Bacteria">जीवाणु</span>]] की चौडाई करीबन 200 nm है।
एक नैनोमीटर का एक मीटर की तुलनात्मक उपमाएं
* अगर एक कंचा एक नैनोमीटर हो तो पृथ्वी एक मीटर होगा।<ref name="NationalG">{{cite journal|last =Kahn| first =जेनिफर
* एक नैनोमीटर एक आदमी की दाढी में उतना बडाव होगा जब तक के वह अपने अस्तरे को अपने चेहरे तक लाता है।<ref name="NationalG"/>
पंक्ति 86:
* Solid-state techniques can also be used to create devices known as '''[[nanoelectromechanical systems]]''' or NEMS, which are related to [[microelectromechanical systems]] or MEMS.
* [[Atomic force microscope]] tips can be used as a nanoscale "write head" to deposit a chemical upon a surface in a desired pattern in a process called '''[[dip pen nanolithography]]'''.
=== Functional approaches ===
These seek to develop components of a desired functionality without regard to how they might be assembled.
* '''[[Molecular electronics]]''' seeks to develop molecules with useful electronic properties.
* Synthetic chemical methods can also be used to create '''[[synthetic molecular motors]]''', such as in a so-called [[nanocar]].
* '''[[Nanoionics]]''' develops devices with fast ion transport at nano scale for conversion and storage of energy, charge and information.
पंक्ति 97:
=== Speculative ===
These subfields seek to [[Futures studies|anticipate]] what inventions nanotechnology might yield, or attempt to propose an agenda along which inquiry might progress. These often take a big-picture view of nanotechnology, with more emphasis on its [[Implications of nanotechnology|societal implications]] than the details of how such inventions could actually be created.
* '''[[Molecular nanotechnology]]''' is a proposed approach which involves manipulating single molecules in finely controlled, deterministic ways.
* '''[[Nanorobotics]]''' centers on self-sufficient machines of some functionality operating at the nanoscale. There are hopes for applying nanorobots in medicine<ref>{{cite journal |author=Ghalanbor Z, Marashi SA, Ranjbar B |title=Nanotechnology helps medicine: nanoscale swimmers and their future applications |journal=Med Hypotheses |volume=65 |issue=1 |pages=198-199 |year=2005 |pmid=15893147}}</ref><ref>{{cite journal |author=Kubik T, Bogunia-Kubik K, Sugisaka M. |title=Nanotechnology on duty in medical applications |journal=Curr Pharm Biotechnol. |volume=6 |issue=1 |pages=17-33 |year=2005 |pmid=15727553}}</ref>, but it may not be easy to do such a thing because of several drawbacks of such devices.<ref>{{cite journal |author=Shetty RC|title=Potential pitfalls of nanotechnology in its applications to medicine: immune incompatibility of nanodevices |journal=Med Hypotheses |volume=65 |issue=5 |pages=998-9 |year=2005 |pmid=16023299}}</ref> Nevertheless, progress on innovative materials and methodologies has been demonstrated with some patents granted about new nanomanufacturing devices for future commercial applications, which also progressively helps in the development towards nanorobots with the use of embedded nanobioelectronics concept.<ref>{{cite journal |author=Cavalcanti A, Shirinzadeh B, Freitas RA Jr., Kretly LC. |title= Medical Nanorobot Architecture Based on Nanobioelectronics |journal=[http://bentham.org/nanotec/ Recent Patents on Nanotechnology]. |volume=1 |issue=1 |pages=1-10 |year=2007}}</ref><ref>{{cite journal |author=Boukallel M, Gauthier M, Dauge M, Piat E, Abadie J. |title= Smart microrobots for mechanical cell characterization and cell convoying. |journal=IEEE Trans. Biomed. Eng. |volume=54 |issue=8 |pages=1536-40 |year=2007|pmid=17694877}}</ref>
* '''[[Programmable matter]]''' based on [[artificial atom]]s seeks to design materials whose properties can be easily and reversibly externally controlled.
पंक्ति 114:
These methods include several different techniques for characterizing [[particle size distribution]]. This characterization is imperative because many materials that are expected to be nano-sized are actually aggregated in solutions. Some of methods are based on [[light scattering]]. Other apply [[ultrasound]], such as [[ultrasound attenuation spectroscopy]] for testing concentrated nano-dispersions and microemulsions<ref> Dukhin, A.S. and Goetz, P.J. "Ultrasound for characterizing colloids", Elsevier, 2002</ref>.
There is also a group of traditional techniques for characterizing [[surface charge]] or [[zeta potential]] of nano-particles in solutions. These information is required for proper system stabilzation, preventing its [[aggregation]] or [[flocculation]]. These methods include [[microelectrophoresis]], [[electrophoretic light scattering]] and [[electroacoustics]]. The last one, for instance [[colloid vibration current]] method is suitable for characterizing concentrated systems.
Next group of nanotechnological techniques include those used for fabrication of nanowires, those used in semiconductor fabrication such as deep ultraviolet lithography, electron beam lithography, [[focused ion beam]] machining, nanoimprint lithography, atomic layer deposition, and molecular vapor deposition, and further including molecular self-assembly techniques such as those employing di-block copolymers. However, all of these techniques preceded the nanotech era, and are extensions in the development of scientific advancements rather than techniques which were devised with the sole purpose of creating nanotechnology and which were results of nanotechnology research.
पंक्ति 121:
The top-down approach anticipates nanodevices that must be built piece by piece in stages, much as manufactured items are currently made. [[Scanning probe microscopy]] is an important technique both for characterization and synthesis of nanomaterials. [[Atomic force microscope]]s and [[scanning tunneling microscope]]s can be used to look at surfaces and to move atoms around. By designing different tips for these microscopes, they can be used for carving out structures on surfaces and to help guide self-assembling structures. By using, for example, [[feature-oriented scanning]]-[[Feature-oriented positioning|positioning]] approach, atoms can be moved around on a surface with scanning probe microscopy techniques. At present, it is expensive and time-consuming for mass production but very suitable for laboratory experimentation.
In contrast, bottom-up techniques build or grow larger structures atom by atom or molecule by molecule. These techniques include [[chemical synthesis]], [[self-assembly]] and positional assembly. Another variation of the bottom-up approach is [[molecular beam epitaxy]] or MBE. Researchers at [[Bell Telephone Laboratories]] like John R. Arthur. Alfred Y. Cho, and Art C. Gossard developed and implemented MBE as a research tool in the late 1960s and 1970s. Samples made by MBE were key to the discovery of the fractional quantum Hall effect for which the [[1998]] [[Nobel Prize in Physics]] was awarded. MBE allows scientists to lay down atomically-precise layers of atoms and, in the process, build up complex structures. Important for research on semiconductors, MBE is also widely used to make samples and devices for the newly emerging field of [[spintronics]].
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