Reading process

From the write and read process sketched so far, some requirements for MO media can be derived (/) a high perpendicular, uniaxial magnetic anisotropy K in order to enable readout with the polar Kerr effect (2) a magnetoopticady active layer with a sufficient figure of merit R 0- where R is the reflectivity and the Kerr angle (T) a Curie temperature between 400 and 600 K, the lower limit to enable stable domains at room temperature and the upper limit because of the limited laser power for writing. 

In the reproducing (reading) process, the presence of the colorless form is detected by difference in reflectivity using the same laser beam at weak power (1 mW), and the signal is picked up by photodiode. In reversible process, the nonrecording area again was obtained by UV irradiation. Practically, in such optical disks using spirothiopyran, an S/N of 54 dB was detected.89-100... 

The rate of dye decomposition should be negligible at exposure energies up to several thousand times the energy absorbed during the read process and increase rapidly thereafter. Dye compositions which exhibit this type of threshold behavior must have relatively high photochemical and thermal stability and decompose by a free radical process above the melting point of the substrate.199... 

Remember that the reading process is the same whether the text is long or short, complex or simple, and the way to respond to the questions cor-recdy is to read closely and carefully. 

The same subject, near the end of his "psilocybin high," reported still another alteration in the reading process ... 

Y (which would be reconverted back to X by a direct photon reading process) into Z, a different, stable state of the system (lock), which can be optically detected without being destroyed (read). This process safeguards the change initially induced by the writing photon. When the written information is to be erased, Z is reconverted back to Y (unlock for example, by addition of a base, as in the example of Figure lc) and... 

The use of photochromic compounds for optical data storage has been proposed. One of the unsolved problems for practical application is the development of techniques that allow nondestructive reading since the optical data are usually read at the same wavelength as that used in the recording process, the data may fade during the reading process. Sisido et al. 101-104 have proposed the use of photochromic... 

For reading data, a similar two-photon process was employed. When isomer B molecules were excited by absorbing two 1064 nm photons, the excitation will cause only the written molecules to emit fluorescence. Although the fluorescence readout method is sensitive, the memory is erased during the reading process because the reverse reaction from the photoexcited isomer B to isomer A takes place, to some extent. Such a destructive readout... 

According to standard portfolio evaluation procedure, the reading process ensured that each portfolio was read at least twice, with discrepancies of more than one point on any one feature (out of nine) prompting a third reading. With our norming, our two-hour-insight, and, perhaps most important, a rubric that was contextually well-validated, we managed to achieve an inter-rater reliability of. 77. 

A 3D optical memory device can be based on different principles. Among them are the write once and read many times principle, based on TP initiated photopolymerization resulting in a photopolymer structure [242] or photo-bleaching of a fluorescent material [250]. The rewritable principle is based mainly on TP induced molecular change. This TP induced molecular change can be an isomerization reaction in the writing process and OP induced fluorescence in the reading process [119, 144, 247, 258],... 

Upto early sixties science at middle level was a general science course. It had a little content and in it no importance was given to science processes. Learning science was a book reading process with no emphasis on experimentation and demonstration. Only once a while some very innovative teachers used to do some demonstrations when teaching science. This process continued till 1964 when UNESCO came into picture, and a new disciplined science course came into existence for middle classes. 

The current magnetic recording technology is based on tapes and discs the writing and reading processes are relatively simple to understand. They are essentially the same in audio, video and computer recording ... 

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