English markers of habitual aspect

The habitual aspect is a form of expression connoting repetition or continuous existence of a state of affairs. In English when present time is referred to, there is no special grammatical marker for the habitual; the simple present is used, as in I go there (every day). However, for past reference English uses the simple past form or either of two alternative markers: used to as in we used to go there (every Thursday), and would as in back then we would go there (every Thursday).

Would

The form [would + infinitive] is employed to talk about a habit or frequent action in a former time. One usually applies [would + infinitive] for the past habitual when one is telling a story about the past.

The past habitual employment of would requires an accompanying indication of the time of occurrence (more specifically than simply before the present): e.g., Last year we would go there frequently, but not simply We would go there frequently.

Cadmium telluride

Cadmium telluride (CdTe) is a stable crystalline compound formed from cadmium and tellurium. It is mainly used as the semiconducting material in cadmium telluride photovoltaics and an infrared optical window. It is usually sandwiched with cadmium sulfide to form a p-n junction solar PV cell. Typically, CdTe PV cells use a n-i-p structure.

Applications

CdTe is used to make thin film solar cells, accounting for about 8% of all solar cells installed in 2011. They are among the lowest-cost types of solar cell, although a comparison of total installed cost depends on installation size and many other factors, and has changed rapidly from year to year. The CdTe solar cell market is dominated by First Solar. In 2011, around 2 GW_p of CdTe solar cells were produced; For more details and discussion see cadmium telluride photovoltaics.

CdTe can be alloyed with mercury to make a versatile infrared detector material (HgCdTe). CdTe alloyed with a small amount of zinc makes an excellent solid-state X-ray and gamma ray detector (CdZnTe).

DVD-RW

A DVD-RW disc is a rewritable optical disc with equal storage capacity to a DVD-R, typically 4.7 GB (4,700,000,000 bytes). The format was developed by Pioneer in November 1999 and has been approved by the DVD Forum. The smaller Mini DVD-RW holds 1.46 GB, with a diameter of 8 cm.

The primary advantage of DVD-RW over DVD-R is the ability to erase and rewrite to a DVD-RW disc. According to Pioneer, DVD-RW discs may be written to about 1,000 times before needing replacement. DVD-RW discs are commonly used to store data in a non-volatile format, such as when creating backups or collections of files. They are also used for home DVD video recorders. One benefit to using a rewritable disc is if there are writing errors when recording data, the disc is not ruined and can still store data by erasing the faulty data.

One competing rewritable format is DVD+RW. Hybrid drives that can handle both, often labeled "DVD±RW", are very popular due to the lack of a single standard for recordable DVDs.

The recording layer in DVD-RW and DVD+RW is not an organic dye, but a special phase change metal alloy, often GeSbTe. The alloy can be switched back and forth between a crystalline phase and an amorphous phase, changing the reflectivity, depending on the power of the laser beam. Data can thus be written, erased and re-written.