Article: Since LED efficacy is inversely proportional to operating temperature, LED technology is well suited for supermarket freezer lighting. Because LEDs produce less waste heat than incandescent lamps, their use in freezers can save on refrigeration costs as well. However, they may be more susceptible to frost and snow buildup than incandescent lamps, so some LED lighting systems have been designed with an added heating circuit. Additionally, research has developed heat sink technologies that will transfer heat produced within the junction to appropriate areas of the light fixture.

Question: What is LED lighting more susceptible to than incandescent light?
Ans: frost

Article: The convergence of these various sources into a uniform theory of groups started with Camille Jordan's Traite des substitutions et des equations algebriques (1870). Walther von Dyck (1882) introduced the idea of specifying a group by means of generators and relations, and was also the first to give an axiomatic definition of an "abstract group", in the terminology of the time. As of the 20th century, groups gained wide recognition by the pioneering work of Ferdinand Georg Frobenius and William Burnside, who worked on representation theory of finite groups, Richard Brauer's modular representation theory and Issai Schur's papers. The theory of Lie groups, and more generally locally compact groups was studied by Hermann Weyl, Elie Cartan and many others. Its algebraic counterpart, the theory of algebraic groups, was first shaped by Claude Chevalley (from the late 1930s) and later by the work of Armand Borel and Jacques Tits.

Question: When did the uniform theory of groups develop from different sources?
Ans: 1870

Article: A commonly seen example is the double happiness symbol , formed as a ligature of and referred to by its disyllabic name (simplified Chinese: ; traditional Chinese: ; pinyin: shuangxi). In handwriting, numbers are very frequently squeezed into one space or combined common ligatures include nian, "twenty", normally read as ershi, sa, "thirty", normally read as sanshi, and xi "forty", normally read as "sishi". In some cases counters are also merged into one character, such as qishi ren "seventy people". Another common abbreviation is with a "T" written inside it, for , , wenti ("question; problem"), where the "T" is from pinyin for the second syllable ti . Since polysyllabic characters are often non-standard, they are often excluded incharcter dictionaries.

Question: What is formed as a ligature?
Ans: double happiness symbol

Article: Copper is biostatic, meaning bacteria will not grow on it. For this reason it has long been used to line parts of ships to protect against barnacles and mussels. It was originally used pure, but has since been superseded by Muntz metal. Similarly, as discussed in copper alloys in aquaculture, copper alloys have become important netting materials in the aquaculture industry because they are antimicrobial and prevent biofouling, even in extreme conditions and have strong structural and corrosion-resistant properties in marine environments.

Question: Name a property that makes copper a good material to use in marine environments?
Ans:
corrosion-resistant