Monday, February 7, 2011

high state of low rank people-低收入工人的高境界

After a whole day's work, the achitechture workers rest on the high structure of the building. They demonstrate their high state even they have low salary compared with other white-collars...

Sunday, February 6, 2011

the elevator: a way to achieve high or low positions-电梯:一种实现可高可低的方式

An old and a new kind of elevator.

An elevator (or lift in British English) is a vertical transport equipment that efficiently moves people or goods between floors (levels, decks) of a building, vessel or other structure. Elevators are generally powered by electric motors that either drive traction cables and counterweight systems like a hoist, or pump hydraulic fluid to raise a cylindrical piston like a jack.
The first reference to an elevator is in the works of the Roman architect Vitruvius, who reported that Archimedes (c. 287 BC – c. 212 BC) built his first elevator probably in 236 BC. In some literary sources of later historical periods, elevators were mentioned as cabs on a hemp rope and powered by hand or by animals.The ancient and medieval elevators used the drive system based on hoist.
In 1852, Elisha Otis introduced the safety elevator, which prevented the fall of the cab if the cable broke. The design of the Otis safety elevator is somewhat similar to one type still used today. A governor device engages knurled roller, locking the elevator to its guides should the elevator descend at excessive speed.
So, from a steam engine the elevator improved itself in a electric functioning.
The development of elevators was led by the need for movement of raw materials including coal and lumber rom hillsides. The technology developed by these industries and the introduction of steel beam construction worked together to provide the passenger and freight elevators in use today.

sound pressure-声压

Sound pressure or acoustic pressure is the local pressure deviation from the ambient (average, or equilibrium) atmospheric pressure caused by a sound wave. Sound pressure can be measured using a microphone in air and a hydrophone in water. The SI unit for sound pressure p is the pascal (symbol: Pa). Sound pressure level (SPL) or sound level is a logarithmic measure of the effective sound pressure of a sound relative to a reference value. It is measured in decibels (dB) above a standard reference level. The commonly used "zero" reference sound pressure in air is 20 µPa RMS, which is usually considered the threshold of human hearing (at 1 kHz).

Sound level meter
 An integrating-averaging sound level meter.

Sound level meters measure sound pressure level and are commonly used in noise pollution studies for the quantification of almost any noise, but especially for industrial, environmental and aircraft noise. However, the reading given by a sound level meter does not correlate well to human-perceived loudness; for this a loudness meter is needed.

the meter and the length-米和长度

The meter [m] is the international standard unit of length, approximately equivalent to 39.37 inches. It was redefined in 1983 as the distance traveled by light in a vacuum in 1/299,792,458 of a second.
Other units of length and their equivalents in meters are as follows:
1 millimeter = 0.001 meter [1 mm]
1 centimeter = 0.01 meter [1 cm]
1 decimeter = 0.1 meter [1 dm]
1 kilometer = 1000 meters [1km]

the Tower of Babel-巴别塔

Tower of Babel, Pieter Bruegel the Elder

The Tower of Babel, according to the Book of Genesis, was an enormous and high tower built in the plain of Shinar.

" 1 Now the whole world had one language and a common speech. 2 As people moved eastward, they found a plain in Shinar and settled there.

 3 They said to each other, “Come, let’s make bricks and bake them thoroughly.” They used brick instead of stone, and tar for mortar. 4 Then they said, “Come, let us build ourselves a city, with a tower that reaches to the heavens, so that we may make a name for ourselves; otherwise we will be scattered over the face of the whole earth.”

 5 But the LORD came down to see the city and the tower the people were building. 6 The LORD said, “If as one people speaking the same language they have begun to do this, then nothing they plan to do will be impossible for them. 7 Come, let us go down and confuse their language so they will not understand each other.”

 8 So the LORD scattered them from there over all the earth, and they stopped building the city. 9 That is why it was called Babel—because there the LORD confused the language of the whole world. From there the LORD scattered them over the face of the whole earth. "
Bible, Genesis 11

ancient chinese proverb-古中国的谚语

"There is no height that has not above him something higher"