Problem: Please answer a question about the following article about Mandolin:
There is confusion currently as to the name of the eldest Vinaccia luthier who first ran the shop. His name has been put forth as Gennaro Vinaccia (active c. 1710 to c. 1788) and Nic. Vinaccia. His son Antonio Vinaccia was active c. 1734 to c. 1796. An early extant example of a mandolin is one built by Antonio Vinaccia in 1759, which resides at the University of Edinburgh. Another is by Giuseppe Vinaccia, built in 1893, is also at the University of Edinburgh. The earliest extant mandolin was built in 1744 by Antonio's son, Gaetano Vinaccia. It resides in the Conservatoire Royal de Musique in Brussels, Belgium.
Where does the mandolin built by Giuseppe Vinaccia reside?
A: University of Edinburgh
Problem: Please answer a question about the following article about Detroit:
Detroit has four border crossings: the Ambassador Bridge and the DetroitWindsor Tunnel provide motor vehicle thoroughfares, with the Michigan Central Railway Tunnel providing railroad access to and from Canada. The fourth border crossing is the DetroitWindsor Truck Ferry, located near the Windsor Salt Mine and Zug Island. Near Zug Island, the southwest part of the city was developed over a 1,500-acre (610 ha) salt mine that is 1,100 feet (340 m) below the surface. The Detroit Salt Company mine has over 100 miles (160 km) of roads within.
How many routes to Canada does Detroit have?
A: four
Problem: Please answer a question about the following article about Antenna (radio):
Recall that a current will reflect when there are changes in the electrical properties of the material. In order to efficiently send the signal into the transmission line, it is important that the transmission line has the same impedance as the elements, otherwise some of the signal will be reflected back into the antenna. This leads to the concept of impedance matching, the design of the overall system of antenna and transmission line so the impedance is as close as possible, thereby reducing these losses. Impedance matching between antennas and transmission lines is commonly handled through the use of a balun, although other solutions are also used in certain roles. An important measure of this basic concept is the standing wave ratio, which measures the magnitude of the reflected signal.
What technique is used to prevent unintentional decrease in signal?
A: Impedance matching
Problem: Please answer a question about the following article about Vacuum:
Vacuum is useful in a variety of processes and devices. Its first widespread use was in the incandescent light bulb to protect the filament from chemical degradation. The chemical inertness produced by a vacuum is also useful for electron beam welding, cold welding, vacuum packing and vacuum frying. Ultra-high vacuum is used in the study of atomically clean substrates, as only a very good vacuum preserves atomic-scale clean surfaces for a reasonably long time (on the order of minutes to days). High to ultra-high vacuum removes the obstruction of air, allowing particle beams to deposit or remove materials without contamination. This is the principle behind chemical vapor deposition, physical vapor deposition, and dry etching which are essential to the fabrication of semiconductors and optical coatings, and to surface science. The reduction of convection provides the thermal insulation of thermos bottles. Deep vacuum lowers the boiling point of liquids and promotes low temperature outgassing which is used in freeze drying, adhesive preparation, distillation, metallurgy, and process purging. The electrical properties of vacuum make electron microscopes and vacuum tubes possible, including cathode ray tubes. The elimination of air friction is useful for flywheel energy storage and ultracentrifuges.
Hight to ultra-high vacuums removes what obstruction?
A:
obstruction of air,