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Compact Disc (CD) is a digital optical disc data storage format. The format was originally developed to store and play only sound recordings but was later adapted for storage of data (CD-ROM). Several other formats were further derived from these, including write-once audio and data storage (CD-R), rewritable media (CD... |
In 2004, worldwide sales of audio CDs, CD-ROMs and CD-Rs reached about 30 billion discs. By 2007, 200 billion CDs had been sold worldwide. CDs are increasingly being replaced by other forms of digital storage and distribution, with the result that audio CD sales rates in the U.S. have dropped about 50% from their peak;... |
The Compact Disc is an evolution of LaserDisc technology, where a focused laser beam is used that enables the high information density required for high-quality digital audio signals. Prototypes were developed by Philips and Sony independently in the late 1970s. In 1979, Sony and Philips set up a joint task force of en... |
In 1974, L. Ottens, director of the audio division of Philips, started a small group with the aim to develop an analog optical audio disc with a diameter of 20 cm and a sound quality superior to that of the vinyl record. However, due to the unsatisfactory performance of the analog format, two Philips research engineers... |
Heitaro Nakajima, who developed an early digital audio recorder within Japan's national public broadcasting organization NHK in 1970, became general manager of Sony's audio department in 1971. His team developed a digital PCM adaptor audio tape recorder using a Betamax video recorder in 1973. After this, in 1974 the le... |
As a result, in 1979, Sony and Philips set up a joint task force of engineers to design a new digital audio disc. Led by engineers Kees Schouhamer Immink and Toshitada Doi, the research pushed forward laser and optical disc technology. After a year of experimentation and discussion, the task force produced the Red Book... |
The Japanese launch was followed in March 1983 by the introduction of CD players and discs to Europe and North America (where CBS Records released sixteen titles). This event is often seen as the "Big Bang" of the digital audio revolution. The new audio disc was enthusiastically received, especially in the early-adopti... |
The CD was planned to be the successor of the gramophone record for playing music, rather than primarily as a data storage medium. From its origins as a musical format, CDs have grown to encompass other applications. In 1983, following the CD's introduction, Immink and Braat presented the first experiments with erasabl... |
Meanwhile, with the advent and popularity of Internet-based distribution of files in lossily-compressed audio formats such as MP3, sales of CDs began to decline in the 2000s. For example, between 2000 - 2008, despite overall growth in music sales and one anomalous year of increase, major-label CD sales declined overall... |
Replicated CDs are mass-produced initially using a hydraulic press. Small granules of heated raw polycarbonate plastic are fed into the press. A screw forces the liquefied plastic into the mold cavity. The mold closes with a metal stamper in contact with the disc surface. The plastic is allowed to cool and harden. Once... |
This method produces the clear plastic blank part of the disc. After a metallic reflecting layer (usually aluminium, but sometimes gold or other metal) is applied to the clear blank substrate, the disc goes under a UV light for curing and it is ready to go to press. To prepare to press a CD, a glass master is made, usi... |
The die is a negative image of the glass master: typically, several are made, depending on the number of pressing mills that are to make the CD. The die then goes into a press, and the physical image is transferred to the blank CD, leaving a final positive image on the disc. A small amount of lacquer is applied as a ri... |
The most expensive part of a CD is the jewel case. In 1995, material costs were 30 cents for the jewel case and 10 to 15 cents for the CD. Wholesale cost of CDs was $0.75 to $1.15, which retailed for $16.98. On average, the store received 35 percent of the retail price, the record company 27 percent, the artist 16 perc... |
CD-R recordings are designed to be permanent. Over time, the dye's physical characteristics may change causing read errors and data loss until the reading device cannot recover with error correction methods. The design life is from 20 to 100 years, depending on the quality of the discs, the quality of the writing drive... |
The ReWritable Audio CD is designed to be used in a consumer audio CD recorder, which will not (without modification) accept standard CD-RW discs. These consumer audio CD recorders use the Serial Copy Management System (SCMS), an early form of digital rights management (DRM), to conform to the United States' Audio Home... |
Due to technical limitations, the original ReWritable CD could be written no faster than 4x speed. High Speed ReWritable CD has a different design, which permits writing at speeds ranging from 4x to 12x. Original CD-RW drives can only write to original ReWritable CDs. High Speed CD-RW drives can typically write to both... |
A CD is read by focusing a 780 nm wavelength (near infrared) semiconductor laser housed within the CD player, through the bottom of the polycarbonate layer. The change in height between pits and lands results in a difference in the way the light is reflected. By measuring the intensity change with a photodiode, the dat... |
The pits and lands themselves do not directly represent the zeros and ones of binary data. Instead, non-return-to-zero, inverted encoding is used: a change from pit to land or land to pit indicates a one, while no change indicates a series of zeros. There must be at least two and no more than ten zeros between each one... |
CDs are susceptible to damage during handling and from environmental exposure. Pits are much closer to the label side of a disc, enabling defects and contaminants on the clear side to be out of focus during playback. Consequently, CDs are more likely to suffer damage on the label side of the disc. Scratches on the clea... |
The digital data on a CD begins at the center of the disc and proceeds toward the edge, which allows adaptation to the different size formats available. Standard CDs are available in two sizes. By far, the most common is 120 millimetres (4.7 in) in diameter, with a 74- or 80-minute audio capacity and a 650 or 700 MiB (... |
The logical format of an audio CD (officially Compact Disc Digital Audio or CD-DA) is described in a document produced in 1980 by the format's joint creators, Sony and Philips. The document is known colloquially as the Red Book CD-DA after the colour of its cover. The format is a two-channel 16-bit PCM encoding at a 44... |
Compact Disc + Graphics is a special audio compact disc that contains graphics data in addition to the audio data on the disc. The disc can be played on a regular audio CD player, but when played on a special CD+G player, it can output a graphics signal (typically, the CD+G player is hooked up to a television set or a ... |
SVCD has two-thirds the resolution of DVD, and over 2.7 times the resolution of VCD. One CD-R disc can hold up to 60 minutes of standard quality SVCD-format video. While no specific limit on SVCD video length is mandated by the specification, one must lower the video bit rate, and therefore quality, to accommodate very... |
Photo CD is a system designed by Kodak for digitizing and storing photos on a CD. Launched in 1992, the discs were designed to hold nearly 100 high-quality images, scanned prints and slides using special proprietary encoding. Photo CDs are defined in the Beige Book and conform to the CD-ROM XA and CD-i Bridge specifica... |
The Red Book audio specification, except for a simple "anti-copy" statement in the subcode, does not include any copy protection mechanism. Known at least as early as 2001, attempts were made by record companies to market "copy-protected" non-standard compact discs, which cannot be ripped, or copied, to hard drives or ... |
A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current through anoth... |
The transistor is the fundamental building block of modern electronic devices, and is ubiquitous in modern electronic systems. First conceived by Julius Lilienfeld in 1926 and practically implemented in 1947 by American physicists John Bardeen, Walter Brattain, and William Shockley, the transistor revolutionized the fi... |
The thermionic triode, a vacuum tube invented in 1907, enabled amplified radio technology and long-distance telephony. The triode, however, was a fragile device that consumed a lot of power. Physicist Julius Edgar Lilienfeld filed a patent for a field-effect transistor (FET) in Canada in 1925, which was intended to be ... |
From November 17, 1947 to December 23, 1947, John Bardeen and Walter Brattain at AT&T's Bell Labs in the United States performed experiments and observed that when two gold point contacts were applied to a crystal of germanium, a signal was produced with the output power greater than the input. Solid State Physics Grou... |
In 1948, the point-contact transistor was independently invented by German physicists Herbert Mataré and Heinrich Welker while working at the Compagnie des Freins et Signaux, a Westinghouse subsidiary located in Paris. Mataré had previous experience in developing crystal rectifiers from silicon and germanium in the Ger... |
Although several companies each produce over a billion individually packaged (known as discrete) transistors every year, the vast majority of transistors are now produced in integrated circuits (often shortened to IC, microchips or simply chips), along with diodes, resistors, capacitors and other electronic components,... |
The essential usefulness of a transistor comes from its ability to use a small signal applied between one pair of its terminals to control a much larger signal at another pair of terminals. This property is called gain. It can produce a stronger output signal, a voltage or current, which is proportional to a weaker inp... |
There are two types of transistors, which have slight differences in how they are used in a circuit. A bipolar transistor has terminals labeled base, collector, and emitter. A small current at the base terminal (that is, flowing between the base and the emitter) can control or switch a much larger current between the c... |
In a grounded-emitter transistor circuit, such as the light-switch circuit shown, as the base voltage rises, the emitter and collector currents rise exponentially. The collector voltage drops because of reduced resistance from collector to emitter. If the voltage difference between the collector and emitter were zero (... |
Providing sufficient base drive current is a key problem in the use of bipolar transistors as switches. The transistor provides current gain, allowing a relatively large current in the collector to be switched by a much smaller current into the base terminal. The ratio of these currents varies depending on the type of ... |
In a switching circuit, the idea is to simulate, as near as possible, the ideal switch having the properties of open circuit when off, short circuit when on, and an instantaneous transition between the two states. Parameters are chosen such that the "off" output is limited to leakage currents too small to affect connec... |
Bipolar transistors are so named because they conduct by using both majority and minority carriers. The bipolar junction transistor, the first type of transistor to be mass-produced, is a combination of two junction diodes, and is formed of either a thin layer of p-type semiconductor sandwiched between two n-type semic... |
BJTs have three terminals, corresponding to the three layers of semiconductor—an emitter, a base, and a collector. They are useful in amplifiers because the currents at the emitter and collector are controllable by a relatively small base current. In an n–p–n transistor operating in the active region, the emitter–base ... |
In a FET, the drain-to-source current flows via a conducting channel that connects the source region to the drain region. The conductivity is varied by the electric field that is produced when a voltage is applied between the gate and source terminals; hence the current flowing between the drain and source is controlle... |
FETs are divided into two families: junction FET (JFET) and insulated gate FET (IGFET). The IGFET is more commonly known as a metal–oxide–semiconductor FET (MOSFET), reflecting its original construction from layers of metal (the gate), oxide (the insulation), and semiconductor. Unlike IGFETs, the JFET gate forms a p–n ... |
FETs are further divided into depletion-mode and enhancement-mode types, depending on whether the channel is turned on or off with zero gate-to-source voltage. For enhancement mode, the channel is off at zero bias, and a gate potential can "enhance" the conduction. For the depletion mode, the channel is on at zero bias... |
The bipolar junction transistor (BJT) was the most commonly used transistor in the 1960s and 70s. Even after MOSFETs became widely available, the BJT remained the transistor of choice for many analog circuits such as amplifiers because of their greater linearity and ease of manufacture. In integrated circuits, the desi... |
The Pro Electron standard, the European Electronic Component Manufacturers Association part numbering scheme, begins with two letters: the first gives the semiconductor type (A for germanium, B for silicon, and C for materials like GaAs); the second letter denotes the intended use (A for diode, C for general-purpose tr... |
The JEDEC EIA370 transistor device numbers usually start with "2N", indicating a three-terminal device (dual-gate field-effect transistors are four-terminal devices, so begin with 3N), then a 2, 3 or 4-digit sequential number with no significance as to device properties (although early devices with low numbers tend to ... |
Manufacturers of devices may have their own proprietary numbering system, for example CK722. Since devices are second-sourced, a manufacturer's prefix (like "MPF" in MPF102, which originally would denote a Motorola FET) now is an unreliable indicator of who made the device. Some proprietary naming schemes adopt parts o... |
The junction forward voltage is the voltage applied to the emitter–base junction of a BJT in order to make the base conduct a specified current. The current increases exponentially as the junction forward voltage is increased. The values given in the table are typical for a current of 1 mA (the same values apply to sem... |
Because the electron mobility is higher than the hole mobility for all semiconductor materials, a given bipolar n–p–n transistor tends to be swifter than an equivalent p–n–p transistor. GaAs has the highest electron mobility of the three semiconductors. It is for this reason that GaAs is used in high-frequency applicat... |
Discrete transistors are individually packaged transistors. Transistors come in many different semiconductor packages (see image). The two main categories are through-hole (or leaded), and surface-mount, also known as surface-mount device (SMD). The ball grid array (BGA) is the latest surface-mount package (currently o... |
In the Pre-Modern era, many people's sense of self and purpose was often expressed via a faith in some form of deity, be that in a single God or in many gods. Pre-modern cultures have not been thought of creating a sense of distinct individuality, though. Religious officials, who often held positions of power, were the... |
The term "modern" was coined in the 16th century to indicate present or recent times (ultimately derived from the Latin adverb modo, meaning "just now). The European Renaissance (about 1420–1630), which marked the transition between the Late Middle Ages and Early Modern times, started in Italy and was spurred in part b... |
The term "Early Modern" was introduced in the English language in the 1930s. to distinguish the time between what we call Middle Ages and time of the late Enlightenment (1800) (when the meaning of the term Modern Ages was developing its contemporary form). It is important to note that these terms stem from European his... |
In the Contemporary era, there were various socio-technological trends. Regarding the 21st century and the late modern world, the Information age and computers were forefront in use, not completely ubiquitous but often present in daily life. The development of Eastern powers was of note, with China and India becoming m... |
In Asia, various Chinese dynasties and Japanese shogunates controlled the Asian sphere. In Japan, the Edo period from 1600 to 1868 is also referred to as the early modern period. And in Korea, from the rising of Joseon Dynasty to the enthronement of King Gojong is referred to as the early modern period. In the Americas... |
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 Qing dynasty (1644–1911) was founded after the fall of the Ming, the last Han Chinese dynasty, by the Manchus. The Manchus were formerly known as the Jurchens. When Beijing was captured by Li Zicheng's peasant rebels in 1644, the Chongzhen Emperor, the last Ming emperor, committed suicide. The Manchus then allied w... |
Society in the Japanese "Tokugawa period" (Edo society), unlike the shogunates before it, was based on the strict class hierarchy originally established by Toyotomi Hideyoshi. The daimyo, or lords, were at the top, followed by the warrior-caste of samurai, with the farmers, artisans, and traders ranking below. In some ... |
On the Indian subcontinent, the Mughal Empire ruled most of India in the early 18th century. The "classic period" ended with the death and defeat of Emperor Aurangzeb in 1707 by the rising Hindu Maratha Empire, although the dynasty continued for another 150 years. During this period, the Empire was marked by a highly c... |
The development of New Imperialism saw the conquest of nearly all eastern hemisphere territories by colonial powers. The commercial colonization of India commenced in 1757, after the Battle of Plassey, when the Nawab of Bengal surrendered his dominions to the British East India Company, in 1765, when the Company was gr... |
The Maratha states, following the Anglo-Maratha wars, eventually lost to the British East India Company in 1818 with the Third Anglo-Maratha War. The rule lasted until 1858, when, after the Indian rebellion of 1857 and consequent of the Government of India Act 1858, the British government assumed the task of directly a... |
The Dutch East India Company (1800) and British East India Company (1858) were dissolved by their respective governments, who took over the direct administration of the colonies. Only Thailand was spared the experience of foreign rule, although, Thailand itself was also greatly affected by the power politics of the Wes... |
Many major events caused Europe to change around the start of the 16th century, starting with the Fall of Constantinople in 1453, the fall of Muslim Spain and the discovery of the Americas in 1492, and Martin Luther's Protestant Reformation in 1517. In England the modern period is often dated to the start of the Tudor ... |
Russia experienced territorial growth through the 17th century, which was the age of Cossacks. Cossacks were warriors organized into military communities, resembling pirates and pioneers of the New World. In 1648, the peasants of Ukraine joined the Zaporozhian Cossacks in rebellion against Poland-Lithuania during the K... |
Traditionally, the European intellectual transformation of and after the Renaissance bridged the Middle Ages and the Modern era. The Age of Reason in the Western world is generally regarded as being the start of modern philosophy, and a departure from the medieval approach, especially Scholasticism. Early 17th-century ... |
The Age of Enlightenment is a time in Western philosophy and cultural life centered upon the 18th century in which reason was advocated as the primary source and legitimacy for authority. Enlightenment gained momentum more or less simultaneously in many parts of Europe and America. Developing during the Enlightenment e... |
Renaissance humanism took a close study of the Latin and Greek classical texts, and was antagonistic to the values of scholasticism with its emphasis on the accumulated commentaries; and humanists were involved in the sciences, philosophies, arts and poetry of classical antiquity. They self-consciously imitated classic... |
The quarrel of the Ancients and the Moderns was a literary and artistic quarrel that heated up in the early 1690s and shook the Académie française. The opposing two sides were, the Ancients (Anciens) who constrain choice of subjects to those drawn from the literature of Antiquity and the Moderns (Modernes), who support... |
The Scientific Revolution was a period when European ideas in classical physics, astronomy, biology, human anatomy, chemistry, and other classical sciences were rejected and led to doctrines supplanting those that had prevailed from Ancient Greece to the Middle Ages which would lead to a transition to modern science. T... |
The changes were accompanied by violent turmoil which included the trial and execution of the king, vast bloodshed and repression during the Reign of Terror, and warfare involving every other major European power. Subsequent events that can be traced to the Revolution include the Napoleonic Wars, two separate restorati... |
The campaigns of French Emperor and General Napoleon Bonaparte characterized the Napoleonic Era. Born on Corsica as the French invaded, and dying suspiciously on the tiny British Island of St. Helena, this brilliant commander, controlled a French Empire that, at its height, ruled a large portion of Europe directly from... |
Italian unification was the political and social movement that annexed different states of the Italian peninsula into the single state of Italy in the 19th century. There is a lack of consensus on the exact dates for the beginning and the end of this period, but many scholars agree that the process began with the end o... |
Beginning the Age of Revolution, the American Revolution and the ensuing political upheaval during the last half of the 18th century saw the Thirteen Colonies of North America overthrow the governance of the Parliament of Great Britain, and then reject the British monarchy itself to become the sovereign United States o... |
The American Revolution begun with fighting at Lexington and Concord. On July 4, 1776, they issued the Declaration of Independence, which proclaimed their independence from Great Britain and their formation of a cooperative union. In June 1776, Benjamin Franklin was appointed a member of the Committee of Five that draf... |
The decolonization of the Americas was the process by which the countries in the Americas gained their independence from European rule. Decolonization began with a series of revolutions in the late 18th and early-to-mid-19th centuries. The Spanish American wars of independence were the numerous wars against Spanish rul... |
When the Central Junta fell to the French, numerous new Juntas appeared all across the Americas, eventually resulting in a chain of newly independent countries stretching from Argentina and Chile in the south, to Mexico in the north. After the death of the king Ferdinand VII, in 1833, only Cuba and Puerto Rico remained... |
The first Industrial Revolution merged into the Second Industrial Revolution around 1850, when technological and economic progress gained momentum with the development of steam-powered ships and railways, and later in the 19th century with the internal combustion engine and electric power generation. The Second Industr... |
Industrialization is the process of social and economic change whereby a human group is transformed from a pre-industrial society into an industrial one. It is a subdivision of a more general modernization process, where social change and economic development are closely related with technological innovation, particula... |
The modern petroleum industry started in 1846 with the discovery of the process of refining kerosene from coal by Nova Scotian Abraham Pineo Gesner. Ignacy Łukasiewicz improved Gesner's method to develop a means of refining kerosene from the more readily available "rock oil" ("petr-oleum") seeps in 1852 and the first r... |
Engineering achievements of the revolution ranged from electrification to developments in materials science. The advancements made a great contribution to the quality of life. In the first revolution, Lewis Paul was the original inventor of roller spinning, the basis of the water frame for spinning cotton in a cotton m... |
In the latter part of the second revolution, Thomas Alva Edison developed many devices that greatly influenced life around the world and is often credited with the creation of the first industrial research laboratory. In 1882, Edison switched on the world's first large-scale electrical supply network that provided 110 ... |
The European Revolutions of 1848, known in some countries as the Spring of Nations or the Year of Revolution, were a series of political upheavals throughout the European continent. Described as a revolutionary wave, the period of unrest began in France and then, further propelled by the French Revolution of 1848, soon... |
Following the Enlightenment's ideas, the reformers looked to the Scientific Revolution and industrial progress to solve the social problems which arose with the Industrial Revolution. Newton's natural philosophy combined a mathematics of axiomatic proof with the mechanics of physical observation, yielding a coherent sy... |
Under Peter I (the Great), Russia was proclaimed an Empire in 1721 and became recognized as a world power. Ruling from 1682 to 1725, Peter defeated Sweden in the Great Northern War, forcing it to cede West Karelia and Ingria (two regions lost by Russia in the Time of Troubles), as well as Estland and Livland, securing ... |
The Victorian era of the United Kingdom was the period of Queen Victoria's reign from June 1837 to January 1901. This was a long period of prosperity for the British people, as profits gained from the overseas British Empire, as well as from industrial improvements at home, allowed a large, educated middle class to dev... |
In Britain's "imperial century", victory over Napoleon left Britain without any serious international rival, other than Russia in central Asia. Unchallenged at sea, Britain adopted the role of global policeman, a state of affairs later known as the Pax Britannica, and a foreign policy of "splendid isolation". Alongside... |
British imperial strength was underpinned by the steamship and the telegraph, new technologies invented in the second half of the 19th century, allowing it to control and defend the Empire. By 1902, the British Empire was linked together by a network of telegraph cables, the so-called All Red Line. Growing until 1922, ... |
The Bourbon Restoration followed the ousting of Napoleon I of France in 1814. The Allies restored the Bourbon Dynasty to the French throne. The ensuing period is called the Restoration, following French usage, and is characterized by a sharp conservative reaction and the re-establishment of the Roman Catholic Church as... |
The Franco-Prussian War was a conflict between France and Prussia, while Prussia was backed up by the North German Confederation, of which it was a member, and the South German states of Baden, Württemberg and Bavaria. The complete Prussian and German victory brought about the final unification of Germany under King Wi... |
The major European powers laid claim to the areas of Africa where they could exhibit a sphere of influence over the area. These claims did not have to have any substantial land holdings or treaties to be legitimate. The European power that demonstrated its control over a territory accepted the mandate to rule that regi... |
At the time of the Berlin Conference, Africa contained one-fifth of the world’s population living in one-quarter of the world’s land area. However, from Europe's perspective, they were dividing an unknown continent. European countries established a few coastal colonies in Africa by the mid-nineteenth century, which inc... |
From the 1880s to 1914, the European powers expanded their control across the African continent, competing with each other for Africa’s land and resources. Great Britain controlled various colonial holdings in East Africa that spanned the length of the African continent from Egypt in the north to South Africa. The Fren... |
Around the end of the 19th century and into the 20th century, the Meiji era was marked by the reign of the Meiji Emperor. During this time, Japan started its modernization and rose to world power status. This era name means "Enlightened Rule". In Japan, the Meiji Restoration started in the 1860s, marking the rapid mode... |
Laws were instituted that required every able-bodied male Japanese citizen, regardless of class, to serve a mandatory term of three years with the first reserves and two additional years with the second reserves. This action, the deathblow for the samurai warriors and their daimyo feudal lords, initially met resistance... |
The Antebellum Age was a period of increasing division in the country based on the growth of slavery in the American South and in the western territories of Kansas and Nebraska that eventually lead to the Civil War in 1861. The Antebellum Period is often considered to have begun with the Kansas–Nebraska Act of 1854,[ci... |
Northern leaders agreed that victory would require more than the end of fighting. Secession and Confederate nationalism had to be totally repudiated and all forms of slavery or quasi-slavery had to be eliminated. Lincoln proved effective in mobilizing support for the war goals, raising large armies and supplying them, ... |
During the Gilded Age, there was substantial growth in population in the United States and extravagant displays of wealth and excess of America's upper-class during the post-Civil War and post-Reconstruction era, in the late 19th century. The wealth polarization derived primarily from industrial and population expansio... |
The creation of a modern industrial economy took place. With the creation of a transportation and communication infrastructure, the corporation became the dominant form of business organization and a managerial revolution transformed business operations. In 1890, Congress passed the Sherman Antitrust Act—the source of ... |
Replacing the classical physics in use since the end of the scientific revolution, modern physics arose in the early 20th century with the advent of quantum physics, substituting mathematical studies for experimental studies and examining equations to build a theoretical structure.[citation needed] The old quantum theo... |
The assertions of Chinese philosophy began to integrate concepts of Western philosophy, as steps toward modernization. By the time of the Xinhai Revolution in 1911, there were many calls, such as the May Fourth Movement, to completely abolish the old imperial institutions and practices of China. There were attempts to ... |
Starting one-hundred years before the 20th century, the enlightenment spiritual philosophy was challenged in various quarters around the 1900s. Developed from earlier secular traditions, modern Humanist ethical philosophies affirmed the dignity and worth of all people, based on the ability to determine right and wrong ... |
Albert Einstein is known for his theories of special relativity and general relativity. He also made important contributions to statistical mechanics, especially his mathematical treatment of Brownian motion, his resolution of the paradox of specific heats, and his connection of fluctuations and dissipation. Despite hi... |
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