Lasers and Their Uses
We have all at some point in our lives used or seen someone use a laser.
They are used in compact disc players for stereos or computers, laser surgery, laser printers, holography, cutting and borring metals, communication, bar-code scanners, etc. Over the past three decades' lasers have become a tool used daily by many people and they have become very useful in scientific research.
As you can see lasers are a very useful and important tool which is why I have chosen this topic to write about.
The term laser is an acronym. It stands for "light amplification by stimulated emission of radiation". They produce a narrow, intense beam of coherent light.
In a laser the atoms or molecules of a crystal, like ruby or garnet-or of a gas, liquid, or other substance-are excited so that more of them are at higher energy levels than are at lower energy levels. If a photon whose frequency corresponds to the energy difference between the excited and ground states strikes an excited atom, the atom is stimulated, as it falls back to a lower energy state, to emit a second photon of the same frequency, in phase with and in the same direction as the bombarding photon. This process is called stimulated emission. The bombarding photon of the emitted photon may then strike other excited atoms, stimulating further emission of photons, all of the same frequency and phase. This process produces a sudden burst of coherent radiation as all the atoms discharge in a rapid chain reaction. The light beam produces is usually pencil thin and maintains its size and direction over very long distances.
Lasers vary greatly in the way they look and what they are used for.
Some lasers are as large as buildings while others can be the size of a grain of salt.
There are many parts to lasers. I will now explain what they are and their uses.
1) Pumping systems:
The pumping system is used to transmit energy to the atoms or molecules of the medium used in the laser.
a. optical pumping systems uses photons provided by a source such as a Xenon gas flash lamp or another laser to transfer energy to the lasing material. The optical source must provide photons which correspond to the allowed transition levels of the lasing material.
b. collision pumping relies on the transfer of energy to the lasing material by collision with the atoms or molecules of the lasing material. Again, energies which correspond to the allowed transition must be provided. This often done by electrical discharge in a pure gas - or gas mixture - in a tube.
In 2001 China entered the WTO it has made major stride in the world economy especially with trade agreements with the biggest capitalist economy and the biggest GDP and most developed country in the world the United States of America which has nearly 2.3 trillion of exported goods and service in 2013 (President, n.d.) When China entered in the WTO it had become the sixth largest economy and the largest market trade and was slightly ahead of Italy and just behind France. “China is third largest trading partner with the U.S and its trade surplus with the U.S. has increased to $201 billion around 2005 and by 2014 the total China-U.S. trade deals was 591 billion”. (Morrison, 2015) It had a global current account of $160 billion around 2005 (Hufbauer, Wong, & Sheth, 2006). As of 2015 “China is the U. S’s second largest trading company and the third largest export company and its biggest source of import”. (Morrison, 2015) Sales from a foreign affiliated U.S. firms in China totaled at 364 billion by 2013. (Morrison, 2015). What is also amazing is that China has the biggest U.S. treasury bonds and that keeps U.S interest rate low. Between 2010 to 2014 General Motor sold more cars in the Chine’s market than in the U.S. market and many U.S. firms participate in Chinese market to stay globally competitive. (Morrison, 2015). This kind of
Living in the world that consists of three thousand different types of mosquitoes is frightening. People got used to a daily routine of waking up and getting to their jobs, that many of them are so focused on their career and family that they do not even notice and pay much attention when they are getting bitten by mosquitoes. Unfortunately not many people were aware of the fact that not all insects are safe, many of mosquitoes transfer infections, but we were not concentrating on that since it was considered not a common issue. As a repercussion, people did not begin to react and notice that something wrong with them when Aedes mosquitoes began their attempt on ruining people’s social, physical and psychological lives by transferring a Zika virus to the once who are bitten.
Lasers. Your cosmetic dental office uses cutting edge dental advanced lasers. By using lasers, your teeth can be whitened. If you are having a smile makeover, a laser might be used to lift and contour gum lines.
National economics are often adversarial in nature, a global contest where countries seek to gain advantage over their neighbors, all in the name of wealth and gain. America is no stranger to the game; the U.S. has been the world’s economic leader for the better part of a century. China, however, is the leading contender for the economic top-spot (), and America continues playing directly into China’s hand. America’s current trading posture with China is drastically skewed in China’s favor; if America is going to preserve its position as the leading economic power, existing U.S.-Chinese trading agreements will need to be revised, and additional regulations must be introduced to promote balanced dealing.
The amount of time taken for the reaction to occur is known as the reaction rate. The rate of a reaction can be commonly explained by Collision Theory. This theory states that in order for a reaction to occur, the particles of each reactant must collide together, with successful collisions resulting in chemical changes. Activation energy is released when the particles hit each other and whether the collision is successful or not is dependant on the amount of activation energy present. The energy's purpose is to allow the element to break its current bonds and form new ones.
For the purpose of this paper we will discuss the Zika Virus; a worldwide public health crisis. The Zika Virus is primarily transmitted through the bite of an infected mosquito and the symptoms experienced are usually mild if any at all. Unfortunately, the Zika Virus can also be transmitted from a pregnant woman to her fetus potentially causing microcephaly; a birth defect in which an infant is born with an abnormally small head size which can in turn cause other developmental problems depending on the severity (CDC, 2016). Concern about the Zika Virus is not new, nor is caution when traveling to an area of the world where a Zika outbreak has recently occurred; however, the prevalence of the Zika Virus is spreading. Prior to 2015 known outbreaks were contained to certain areas in Africa, Southeast Asia, and the Pacific Islands, in mid-2015 the first confirmed case of Zika virus infections were announced in Brazil and has since spread throughout the Americas (CDC,
The year is 2001. China joins the World Trade Organization (WTO) and Americans give way to the new “Asian powerhouse.” China has grown 9 percent a year for more than 25 years and is recorded as the fastest growth rate for an economy in history according to and abstract by Peter Katel in the CQ Researcher. With exports rising from 38.8 billion to 196.7 billion (a 400% increase) from 1994 to 2004 to the US alone, no wonder why China has gained new popularity with the business world. In the same article Peter Katel goes on to state that two-thirds of the world’s copiers, microwave ovens, DVD players and shoes are manufactured in China. With this powerful advantage that China has, its promising future does not seem that far away. The graph to the left shows the US merchandise trade with China. As you can see, the US exports to China have fallen and its imports from China have increased greatly from 1994 to 2004.
The Zika virus also known as Zika Fever is a disease that is causing hysteria across North America and other places in the world today. This disease is passed on by a female mosquito’s bite or by sexual intercourse. Having Zika can cause many different things for different people such as for pregnant women it could cause birth defects to the unborn child. Another result of the virus is paralysis (Guillain-Barre Syndrome) in certain cases. Some side effects of being bitten are fever, rash,
There would be a change in the amount of energy given off that is getting greater, the more carbon atoms in the fuel, the more there are more bonds to be broken and formed, thus producing more energy. In a chemical reaction, bonds in the reactant molecule are broken and new ones are formed. Atoms are rearranged and rearranged. Energy has to be put in to break bonds, and energy is given out when bonds are formed.’ When the total energy put in is greater than the energy put out, the substance cools down (it is endothermic).
The massive increase in the Chinese trading relations was fueled by the United States in the year 1979 through the normal trade relations between the two countries. In addition, the Chinese non-concession to the World Trade Organization (WTO) in the year 2001 also facilitated its trading activities with different countries including the United States (Kaplan, 57). However, trading relations with the Chinese have been uneasy resulting from the massive trade imbalances in the recent past, which grows exponentially. The protectionist policies of the United States especially in Washington and Beijing have been putting pressure on the Chinese to revalue their currency as well as protecting it from counterfeits, which may be of adverse effects to the trading relations. This paper gives a comprehensive discussion on the foreign trade relations with china. It further gives an elaborate discussion on the impacts of foreign tr...
The current trade imbalance is caused in large part by intrinsic features of China's labor market and consumer base. The vast majority of China's 1.3 billion people still live in rural areas. China has, by some estimates, a surplus rural labor force of 120 million people, many of whom migrate to industrial centers to look for factory work, and drive down wages. As long as wages are low, the United States will continue to gobble up products made in China, while Chinese consumers will prefer to buy cheaper, homespun alternatives to American products. The rise in trade deficit with China has come at a cost to jobs in the United States, accordin...
Regan unfortunately was not aware that the technology required to make SDI a functioning program did not even exist in the laboratories and almost 10 years of dedicated research would be needed to determine if the laser and ray gun were even po...
Reactions occur when the particles of reactants collide together continuously. If they collide with sufficient energy, then they will react. The minimum amount of kinetic energy required for particles at the time of collision is called the activation energy and this theory is known as the ?collision theory?.
Even though there are advantages as well as disadvantages, the need for international language for communication, politics, economics and security is necessary and English is the best “language candidate” for that function. English is a language spread all over the world and it is used by millions and millions of speakers. According to my opinion, people should use English as a tool to communicate with all cultures but every country must keep their culture and language is a great part of it. In conclusion, language defines identity of a country and everyone should keep their language and explore others.