Problem: There are quite a few different dielectrics that can be chosen to provide different insulating values depending on the requirements of the circuit. Some of these dielectrics are polytetrafluoroethylene (Teflon), FR-4, FR-1, CEM-1 or CEM-3. Well known pre-preg materials used in the PCB industry are FR-2 (phenolic cotton paper), FR-3 (cotton paper and epoxy), FR-4 (woven glass and epoxy), FR-5 (woven glass and epoxy), FR-6 (matte glass and polyester), G-10 (woven glass and epoxy), CEM-1 (cotton paper and epoxy), CEM-2 (cotton paper and epoxy), CEM-3 (non-woven glass and epoxy), CEM-4 (woven glass and epoxy), CEM-5 (woven glass and polyester). Thermal expansion is an important consideration especially with ball grid array (BGA) and naked die technologies, and glass fiber offers the best dimensional stability.
To what type of packaging is thermal expansion particularly critical?
The answer is the following: ball grid array

Problem: A broad way of defining adolescence is the transition from child-to-adulthood. According to Hogan & Astone (1986), this transition can include markers such as leaving school, starting a full-time job, leaving the home of origin, getting married, and becoming a parent for the first time. However, the time frame of this transition varies drastically by culture. In some countries, such as the United States, adolescence can last nearly a decade, but in others, the transitionoften in the form of a ceremonycan last for only a few days.
How long does the United States believe adolescence lasts?
The answer is the following: nearly a decade

Problem: In China, urbanization increased as the population grew and as the division of labor grew more complex. Large urban centers, such as Nanjing and Beijing, also contributed to the growth of private industry. In particular, small-scale industries grew up, often specializing in paper, silk, cotton, and porcelain goods. For the most part, however, relatively small urban centers with markets proliferated around the country. Town markets mainly traded food, with some necessary manufactures such as pins or oil. Despite the xenophobia and intellectual introspection characteristic of the increasingly popular new school of neo-Confucianism, China under the early Ming dynasty was not isolated. Foreign trade and other contacts with the outside world, particularly Japan, increased considerably. Chinese merchants explored all of the Indian Ocean, reaching East Africa with the treasure voyages of Zheng He.
Under what rule was China not isolated?
The answer is the following: the early Ming dynasty

Problem: Following a series of arcade game successes in the early 1980s, Nintendo made plans to create a cartridge-based console called the Famicom. Masayuki Uemura designed the system. Original plans called for an advanced 16-bit system which would function as a full-fledged computer with a keyboard and floppy disk drive, but Nintendo president Hiroshi Yamauchi rejected this and instead decided to go for a cheaper, more conventional cartridge-based game console as he felt that features such as keyboards and disks were intimidating to non-technophiles. A test model was constructed in October 1982 to verify the functionality of the hardware, after which work began on programming tools. Because 65xx CPUs had not been manufactured or sold in Japan up to that time, no cross-development software was available and it had to be produced from scratch. Early Famicom games were written on a system that ran on an NEC PC-8001 computer and LEDs on a grid were used with a digitizer to design graphics as no software design tools for this purpose existed at that time.[citation needed]
Who was the Nintendo president at the time?
The answer is the following:
Hiroshi Yamauchi