Understanding Phosphorous, Boron and Other Semiconductor Materials

Introducing Phosphorous The process of doping introduces an atom of another element into the silicon crystal to alter its electrical properties. The dopant has either three or five valence electrons, as opposed to silicons four. Phosphorus atoms, which have five valence electrons, are used for doping n-type silicon (phosphorous provides its fifth, free, electron). A phosphorus atom occupies the same place in the crystal lattice that was occupied formerly by the silicon atom it replaced. Four of its valence electrons take over the bonding responsibilities of the four silicon valence electrons that they replaced. But the fifth valence electron remains free, without bonding responsibilities. When numerous phosphorus atoms are substituted for silicon in a crystal, many free electrons become available. Substituting a phosphorus atom (with five valence electrons) for a silicon atom in a silicon crystal leaves an extra, unbonded electron that is relatively free to move around the crystal. The most common method of doping is to coat the top of a layer of silicon with phosphorus and then heat the surface. This allows the phosphorus atoms to diffuse into the silicon. The temperature is then lowered so that the rate of diffusion drops to zero. Other methods of introducing phosphorus into silicon include gaseous diffusion, a liquid dopant spray-on process, and a technique in which phosphorus ions are driven precisely into the surface of the silicon. Introducing Boron   Of course, n-type silicon cannot form the electric field by itself; its also necessary to have some silicon altered to have the opposite electrical properties. So it’s boron, which has three valence electrons, that’s used for doping p-type silicon. Boron is introduced during silicon processing, where silicon is purified for use in PV devices. When a boron atom assumes a position in the crystal lattice formerly occupied by a silicon atom, there is a bond missing an electron (in other words, an extra hole). Substituting a boron atom (with three valence electrons) for a silicon atom in a silicon crystal leaves a hole (a bond missing an electron) that is relatively free to move around the crystal. Other semiconductor materials. Like silicon, all PV materials must be made into p-type and n-type configurations to create the necessary electric field that characterizes a PV cell. But this is done a number of different ways depending on the characteristics of the material. For example, amorphous silicons unique structure makes an intrinsic layer or â€Å"i layer† necessary. This undoped layer of amorphous silicon fits between the n-type and p-type layers to form what is called a p-i-n design. Polycrystalline thin films like copper indium diselenide (CuInSe2) and cadmium telluride (CdTe) show great promise for PV cells. But these materials cant be simply doped to form n and p layers. Instead, layers of different materials are used to form these layers. For example, a window layer of cadmium sulfide or another similar material is used to provide the extra electrons necessary to make it n-type. CuInSe2 can itself be made p-type, whereas CdTe benefits from a p-type layer made from a material like zinc telluride (ZnTe). Gallium arsenide (GaAs) is similarly modified, usually with indium, phosphorous, or aluminum, to produce a wide range of n- and p-type materials.

Eliot as Dramatist - 1935 Words

T.S. Eliot as a dramatist Introduction American-English poet, playwright, and critic, a leader of the modernist movement in literature. Eliot was awarded the Nobel Prize for literature in 1948. His most famous work is THE WASTE LAND, written when he was 34. On one level this highly complex poem descibes cultural and spiritual crisis. The point of view which I am struggling to attack is perhaps related to the metaphysical theory of the substantial unity of the soul: for my meaning is, that the poet has, not a personality to express, but a particular medium, which is only a medium and not a personality, in which impressions and experiences combine in peculiar and unexpected ways. (from Tradition and the Individual Talent,†¦show more content†¦In 1922 Eliot founded the Criterion, a quarterly review that he edited until he halted its publication at the beginning of World War II. With the help of Pound, who had raised money from friends and patrons, Eliot left the bank. In 1925 he joined the publishing house of Faber and Gwyer (later Faber and Faber), becoming eventually one of the firms directors. Between the years 1917 and 1919, Eliot was an assistant editor of the journal the Egoist. From 1919 onward he was a regular contributor to the Times Literary Supplement. In the 60 years from 1905 to his death, Eliot published some 600 articles and reviews. Eliots principal purpose in his literary-critical essays was the elucidation of works of art and the correction of taste. He wanted to revive the appreciation of the 17th-century Metaphysical poets, referring to such writers as Donne, Crashaw, Vaughan, Lord Herbert, and Cowley. He admitted that it is extremely difficult to define metaphysical poetry and decide what poets practiced it, but praised the complex mixture of intellect and passion that characterized their work. In the essay Religion and literature (1935) Eliot stated that literary criticism should be completed by criticism from a definite ethical and theological standpoint. Eliots first marriage from 1915 with the ballet-dancer Vivienne Haigh-Wood turned out to be unhappy. She was temperamental, full of life, restless. Her arrival at menstruation brought extreme moodShow MoreRelatedCritical Appreciation Of T. S. Eliot s The Metaphysical Poets1382 Words   |  6 Pagessignificance. Eliot begins the essay by praising Grierson’s scholarly edition of Metaphysical lyrics and Poems of the 17th  Century as an admirable â€Å"piece of criticism, and a provocation of criticism.† According to Eliot that the phrase ‘metaphysical poetry’ has been used as a term of abuse or as a label of a quaint and pleasant taste. He raises a question whether the so-called metaphysical poets formed a new school or movement or whether it was just a mere continuation of some older tradition. Eliot statesRead MoreEssay on The Sacred Wood and Began the Waste Land by T.S. Eliot626 Words   |  3 PagesT.S. Eliot was one of many award winning book wr iters. T.S. Eliot was known as a ‘’hard working writer.’’ He published his first book in 1915, starting off his career as a writer/poet. T.S. Eliot was born September 26, 1888 in St. Louis. He was the youngest of seven born to Henry Ware Eliot and Charlotte Eliot. In 1906–10, undergraduate at Harvard. He discovered the Symbolists and Lafarge. He was in editor of the Harvard Advocate, a literary magazine. In 1911-14 he was in graduate student in philosophyRead MoreEmily Dickinson Essay1254 Words   |  6 Pagesher religious beliefs and ideals set by her father had a major impact on her writings as well. Another important poet during this time period was that of T.S. Eliot. In looking at his writing style it will help to see the major influences of writing at this time. T.S. Eliot, was an American-born English poet, literary critic, dramatist, and winner of the Nobel Prize for literature, who is best known for his poem The Waste Land, one of the most widely discussed literary works of the early 20thRead MoreT.S. Eliots Writing Style and Use of Symbolism790 Words   |  4 Pagesfar can possibly find out how far one can go,† T.S. Eliot is basically trying to say that only people who push their limit can actually see how much they can really accomplish. T.S. Eliot made poetry that showed his negative views on life, people, and world. T.S. Eliot took poetry to another level by the way he writes and uses symbolism. Thomas Stearns was born on September 26, 1888. He was born in St. Louis, Missouri. His father was Henry ware Eliot who was the president of the Hydraulic-press companyRead MoreEssay on Victorian Age1258 Words   |  6 Pagestook an even broader step in her novels. She wrote about womens sexual passions . Never before had a woman wrote a novel of this content. Unquestionably, the three great masters of Victorian novels were Charles Dickens, William Thackerary and George Eliot. Of the three, Dickens was the most popular with the Victorian public and the most difficult to evaluate today. Dickens novels cannot really be judged. He used a difficult more inclusive type of writing. His novels are read more often because readersRead MoreAnalysis Of The Poem Preludes : A Modern Craft Essay1524 Words   |  7 PagesPreludes: A Modern Craft Thomas Stearn Eliot (T.S. Eliot), an all-American writer was born into a wealthy family in St. Louis, Missouri in 1888. His father, Henry Ware Eliot, was the president of the Hydraulic-Press Brick Company, and his mother, Charlotte Champe Stearns, wrote poetry and volunteered at the Humanity Club (Bush). Also, his grandfather, William Greenleaf Eliot, founded the Unitarian church who contributed to his most outstanding poem, Preludes, a 4 stanza poem(Bush). Being under theRead MoreThe Libation Bearers and Hamlet1308 Words   |  6 PagesAge. It is the age when Greek dramatists hailed human heroes more than Olympian gods. Gilbert Murray compares the tragedies as: â€Å"There are first the broad similarities of situation between what we may call the original sagas on both sides; that is the general story of Orestes and Hamlet respectively. But secondly, there is something much more remarkable; when these sagas were worked up into tragedies, quite independently and on very different lines, by great dramatists of Greece and England, not onlyRead MoreThe Libation Bearers and Hamlet1302 Words   |  6 PagesAge. It is the age when Greek dramatists hailed human heroes more than Olympian gods. Gilbert Murray compares the tragedies as: â€Å"There are first the broad similarities of situation between what we may call the original sagas on both sides; that is the general story of Orestes and Hamlet respectively. But secondly, there is something much more remarkable; when these sagas were worked up into tragedies, quite independently and on very different lines, by great dramatists of Greece and England, not onlyRead MoreSymbolism and Religious Drama: T.S. Eliot’s Murder in the Cathedral2754 Words   |  12 PagesMurder in the Cathedral By T. S. Eliot In 1163, a quarrel began between the British King Henry II and the Archbishop of Canterbury, Thomas Becket. The men had been good friends, but each felt that his interests should be of primary concern to the nation and that the other should acquiesce to his demands. Becket fled to France in 1164 in order to rally support from the Catholic French for his cause and also sought an audience with the Pope. After being officially (although not personally) reconciledRead MorePost-Shakespearean Dramatists and declining of drama during post-Shakespeare period2502 Words   |  11 Pages1 Post-Shakespearean Dramatists Introduction - Post Shakespearean drama/Jacobean drama (that is, the drama of the age of James 11603-1625) was a decadent form of the drama of Shakespeare and his contemporaries. The Elizabethan age was the golden age of English drama.With the turn of the century the drama in England also took a turn. It does not mean that there were no dramatists left. There certainly was a large number of them, but none of them could come anywhere near Shakespeare.Just as after

Pawn Broking Business Business Statistics

Question: Discuss about Pawn Broking Business for Business Statistics. Answer: 1: Pawn broking business started in the early 19th century in Singapore. By the end of the 21st century, it serves the "white collar" customers in the country. Pacific Pawn Brokers is one of the leading pawn broking company, that operates in Hong Kong. The firm wants to start a business in Singapore. The company intends to be among the top three businesses in the country. So the company wishes to know about the state of the economy of the country for running this business. This requires statistical investigation of previous years data relating to the number of pledges received, the number of pledges redeemed; some loans are given, etc. A sample of monthly pawnshop data from the year 1980 to the year 2015 has been taken from the site of Department of Statistics, Statistical Tables from singstat Table Builder for the analysis (Tablebuilder.singstat.gov.sg, 2016).The figures of a monthly number of pledges received per month have been segmented into two parts - before the year 2000 and after the year 2000. Various descriptive statistics measures have been used to figure out the change in some pledges received. The data is basically a time series data. Plotting the values of No. Of pledges against the dates the above graph is obtained. The graph shows a steady increase in the costs from 1980 to May 2010 and a rapid growth in the values after that. No such outliers can be spotted from the graph. The measures of central tendency used are arithmetic mean and median (Boone and Boone 2012). The mean and the median values before the year 2000 has been 195988 and 194178 respectively. The costs for the years after 2000 are 264511 and 242501. There is a great change in central tendency values before and after 2000. The central tendency value reveals that the number of pledges after the year 2000 has increased more than 25%. The measures of dispersion used in this case are the range, inter quartile range and standard deviation (Bickel and Lehmann 2012). 90% of the values of a variable is expected to lie within the inter quartile range. A significant difference between the values of range and Inter quartile range indicates the presence of outlier ( Wan et al. 2014). Before the year 2000, the values of range and inter quartile range are 126519 and 41658.0 respectively while that after 2000 is 176498 and 88168 respectively. The difference between the range and inter quartile range is more for the years after 2000 than for the years before 2000. The standard deviation values for the number of pledges received before the year 2000 is 26975.98 while that after the year 2000 is 52275.27 The measures of central tendency and measures of dispersion values reveal that the number of pledges received after the year 2000 is rapidly growing. The values after 2000 are greatly dispersed and has a heavy-tailed distribution. The result means the numbers of pledge received is increasing very fast in the current years. This is also evident from the graph (Kołacz and Grzegorzewski 2016). 2: The mean value of number of pledges after the year 2000 is 264511.The probability that the sample mean is above 26000 has to be calculated. The likelihood of the value is computed to ensure if the sample is repeated will the value be also higher than 26000.The sample size is 188.As the scale of the sample is considerably large, (more than 30), the population standard deviation can be approximated by sample standard deviation. The distribution of the sample mean can be assumed to be a standard normal (Hoenig and Heisey 2012). So the probability that the sample mean is greater than 260000 is given by: =1-ф(1.18319) =1-0.19886 =0.80114. The upper and lower confidence limit is given by: UCL=Xbar +s/sqrt(n)*z LCL= Xbar-s/sqrt(n)*z The tabulated value of z at 90% level of significance is given by 1.282(Altman et al. 2013). So the confidence interval for pledge received after the year 2000 is: UCL=264511+3812.566*1.282=271199.205 LCL=264511-3812.566*1.282=261270.59425804 The confidence interval for pledged received before the year 2000 is: UCL=195988+1.282*1741.292=198159.483654 LCL=195988-1.282*1741.292=193688.516346 The confidence interval for the period before the year 2000 is (193424.667926,1948423.332074) and the confidence interval for the period after the year 2000 is (271199.25,261270.59425804). This means that if the sample is repeated as many times as required the value of the average will lie within this interval. So it can be concluded that the mean value for the period of the year 2000 is greater than the mean value before the year 2000. C.The assumptions made for the purpose of constructing the confidence interval are: 1.The population standard deviation has been approximated by sample standard deviation as the sample size is quite large. 2.The distribution of sample mean is assumed to be normal. If the sample standard deviation cannot be approximated by population standard deviation, then estimated value of sample standard deviation is to be used. Then the distribution of test statistic will be t distribution instead of standard normal(Aron, Coups and Aron 2013). The confidence interval will be: UCL= Xbar +s/sqrt(n)*t LCL= Xbar -s/sqrt(n)*t The value of t at 90% confidence limit for df = 191 is 1.660. Then the confidence interval will be (193097.5,198878.6) for the period before 2000 and (258182.2,270839.9) for the period after 2000(Kruschke 2013). 3: There has been a financial crisis in the year 2008-2009 which has made the director of the Pacific Pawn Brokers company to think that the amount of loans redeemed including interest has been lowered after this financial crisis. To verify the statement a test has been conducted to check whether the mean amount of loans redeemed before and after the financial crisis has changed significantly or not. Here 2 represents the mean amount of loans redeemed before 2009 and 1 represent the mean amount of loan redeemed after the year 2009.So to test whether the two mean values are equal, or the mean value has been increased after the financial crisis (2008-2009) is to test H0: against H1: 12(Bera, Galvao and Wang 2014). The value of population standard deviation has to be estimated from sample standard deviation. The test statistic for the purpose of testing is given by: T= Where sp denotes the square root of the pooled variance. Where s1 is the standard deviation of the first sample and s2 is the standard deviation of the second sample. The value of pooled variance is 136.8934. The test statistic is said to follow a t distribution with (n1+n2-2)=182 degrees of freedom. Under the null hypothesis, the value of the t statistic is 63.09618. The tabulated value of t statistic at 0.05% level of significance for degrees of freedom= 182 is 1.984.So the value of observed t is greater than tabulated value. Therefore the null hypothesis is rejected. The assumptions for the test of this hypothesis is that the variance that has been used for the purpose of the test statistic is pooled variance. Pooled variance of the sample can be used if the sample variance for each population is assumed to be equal. In this case, the two standard deviations are unequal. So instead of pooled variance, one can use the following statistic: The value of t statistic is then 11.66796.The value of t statistic is greater than observed value of t is 1.984, so the given hypothesis is rejected. 4: The above test suggests that the mean value for the period before the financial crisis and the period after the financial crisis are different. The amount of loan redeemed after the financial crisis has been increased. The test for whether the mean value of some credits redeemed before and after the year of the financial crisis has been done by taking the mean or the average values. It may often happen that the mean values are affected by outliers. To cater this problem, a robust measure has to be used test the hypothesis. For this, one can use the median test to determine whether the median value of the two tests are equal are not (Pan et al. 2014). In the median test, the hypothesis of the test is, H0:me1=me2 against H1:me1me2, where median 1 is the median for the sample of years before 2009 crisis and me 2 is the median of the years after 2009 financial crisis. The statistic for the test is: Z is said to follow a standard normal distribution. So the statistic is rejected at 5% level of significance if the calculated value of z is greater than 1.645. The calculated value of z is 135.9881.So the given hypothesis is rejected.That means the median of the two distribution are not equal(Brys, Hubert and Struyf 2012). The mean value has been calculated by taking only nine years before the financial crisis. But that was the period of economic instability. So there were great fluctuations in the figures of loans redemption with interest. The test will be better if the sample is taken from the year 1990.So a test for the mean value has been done by taking the sample from the year 1990 to 2009 and 2010 to 2015, and the arithmetic mean values were compared with the help of t-test.The test statistic for the test is: Where Is the mean value from the year 1990 to 2009.The value of the t statistic calculated from the test -0.26599. The value of t observed from the t table at 0.05 % level of significance for degrees of freedom is 301 is 1.667.As the value of t observed is less than t tabulated, the given hypothesis is accepted. So this sample also reveals that the amount of loans redeemed post-financial crisis year has been increased. References: Altman, D., Machin, D., Bryant, T. And Gardner, M. Eds., 2013.Statistics with confidence: confidence intervals and statistical guidelines. John Wiley Sons. Aron, A., Coups, E. And Aron, E.N., 2013.Statistics for The Behavioral and Social Sciences: Pearson New International Edition: A Brief Course. Pearson Higher Ed. Bera, A.K., Galvao, A.F. and Wang, L., 2014. On testing the equality of mean and quantile effects.Journal of Econometric Methods,3(1), pp.47-62. Bickel, P.J. and Lehmann, E.L., 2012. Descriptive statistics for nonparametric models IV. Spread. InSelected Works of EL Lehmann(pp. 519-526). Springer US. Boone, H.N. and Boone, D.A., 2012. Analyzing likert data.Journal of extension,50(2), pp.1-5. Brys, G., Hubert, M. And Struyf, A., 2012. A robust measure of skewness.Journal of Computational and Graphical Statistics. Hoenig, J.M. and Heisey, D.M., 2012. The abuse of power.The American Statistician. Kołacz, A. And Grzegorzewski, P., 2016. Measures of dispersion for multidimensional data.European Journal of Operational Research,251(3), pp.930-937. Kruschke, J.K., 2013. Bayesian estimation supersedes the t test.Journal of Experimental Psychology: General,142(2), p.573. Pan, Y., Caudill, S.P., Li, R. And Caldwell, K.L., 2014. Median and quantile tests under complex survey design using SAS and R.Computer methods and programs in biomedicine,117(2), pp.292-297. Tablebuilder.singstat.gov.sg. (2016). Homepage | singstat Table Builder. [online] Available at: https://www.tablebuilder.singstat.gov.sg/publicfacing/mainmenu.action [Accessed 19 Aug. 2016]. Wan, X., Wang, W., Liu, J. And Tong, T., 2014. Estimating the sample mean and standard deviation from the sample size, median, range and/or interquartile range.BMC medical research methodology,14(1), p.135.