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== '''[[NMR spectroscopy]]''' ==
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'''NMR spectroscopy''' (MR spectroscopy, NMR or Nuclear Magnetic Resonance Spectroscopy) measures the energy differences between the spin states of nuclei in the presence of a magnetic field by using radio frequency electromagnetic radiation.<ref> I. I. Rabi.(1937) Phys. Rev., 51  652</ref><ref>N. Bloembergen, E. Purcell and R.V.Pound. (1948). Phys. Rev.  73, 679.</ref> <ref>F. Bloch, W. Hansen, and M.E. Packard, (1946) Phys. Rev. 69, 127.</ref> The energy differences between the spin states of the nuclei depend upon the nature of the atom and are influenced by its environment. However, NMR spectroscopy is not limited to measurement of the energy differences between the spin states. NMR signals are also influenced by the motion of the nucleus and the rotational motion of the molecule within which the observed nucleus resides. Therefore, NMR spectroscopy provides  static (structure and composition) as well as dynamic information regarding the system of interest, e.g.,  [[protein]]s, [[DNA]] and other natural products.
==Footnotes==
 
Pulses of radio-frequency electromagnetic radiation can be used to perturb the nuclear spin systems in a variety of ways; the time dependent response of the system of interest can be recorded and analyzed:  
* to correlate different spectral properties of nuclei and/or
* to extract information regarding interactions between nuclear spins within the same molecule and/or
* to obtain information regarding intermolecular interactions. 
The amplitude, frequency, phase and duration of pulses of radio-frequency electromagnetic radiation, as well as static and dynamic position dependent magnetic fields, can be varied in many  combinations giving rise to a wide variety of NMR spectroscopic experiments.
 
NMR spectroscopic techniques are used extensively for structural elucidation of natural products and for quantitative analysis of components of complex mixtures such as body fluids.  However, its applications are not limited to these systems; and
NMR spectroscopy has been used for the study of matter in disordered, ordered and partially ordered systems such as gases, liquids, [[quantum fluids]]
<ref>D.D.Osheroff, W.J.Gully, R.C.Richardson and D.M.Lee, Phys. Rev. Lett. (1972) 29, 920 </ref> <ref>http://nobelprize.org/nobel_prizes/physics/laureates/1996/lee-lecture.pdf </ref>, 
superconductors, solutions, amorphous solids, crystalline solids, [[liquid crystals]], membranes and living organisms. NMR spectroscopic methods have also found use in  [[quantum computing]].
 
''[[NMR spectroscopy|.... (read more)]]''
 
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Latest revision as of 10:19, 11 September 2020

Categories of smart home devices shown on Amazon's website in April 2023.

The phrase smart home refers to home automation devices that have internet access. Home automation, a broader category, includes any device that can be monitored or controlled via wireless radio signals, not just those having internet access. Whether the device is powered by the electrical grid or by battery, if it uses the home Wi-Fi network and if an internet logon needs to be created to use it, then it is smart home technology.

Collectively, all the smart home devices on every home's Wi-Fi network helps to make up what is called the Internet of Things (IoT), a huge sea of sensors and control devices across the world that are capable of being accessed from afar via the internet. One of the key reasons such devices need internet access is so that the manufacturer can periodically download updated firmware to the device to keep it up-to-date. However, being available via the internet also means that such devices are, potentially, available for spying or hacking. Today, homes may contain dozens or even hundreds of such devices, and consumers may enjoy their benefits while knowing little about how they work, or even realizing that they are present.

Not all home automation is "smart"

Many remotely controllable devices do not require internet access. They may instead have physical control devices that use either RF (“Radio Frequency”) or IR (“Infrared”) beams, two different kinds of energy used in remote controls to communicate commands. Non-"smart" home automation may also present security risks, because the control signals can be hijacked by bad actors with the right signaling equipment. Garage door openers are of particular note in this regard. Modern automobiles, in fact, are full of automation similar to home automation, and cars are hackable by bad actors in a number of ways. See Wikipedia's Automotive hacking article for more information.

Incompatibility hassles

At present, consumers must make sure that the smart device they wish to use is specified to be compatible whichever phone/tablet operating system they use (Apple vs. Android). Since smart home products emerged in the absence of any standard, a morass of competing methods for networking, control and monitoring now exist. For some products, consumers may need to buy an expensive hub, or bridge, a device that is specific to one vendor. Products made by different manufacturers but performing the same function are typically not interoperable. Consumers often need to open a different app on their smartphone or tablet in order to control devices by each manufacturer. This may make it too expensive and awkward to try out competing devices, leaving consumers stuck with the product they bought originally or else having to add yet more apps to their phones.

Security concerns

Security for smart home products has been uneven and sometimes seriously inadequate. Smart thermostats which can monitor whether a home's occupants are present or not, entry-way locks, robotic vacuums that work with a map of the house, and other smart home devices can present very real dangers if hackers can access their data.

Matter, an emerging standard

Matter is emerging standard in 2023 intended to increase security, reliability and inter-operability of smart-home devices. About ten years ago, industry consortiums formed to work on standards for smart home device communications, and their underlying wireless communications, which would make it possible for products from all vendors to work together seamlessly and provide fast performance, privacy, and security and would work even if there is not connection to the outside internet (i.e., no connection to "the cloud" or to servers).

Footnotes