7 resultados para Weyden, Rogier van der, 1399 or 1400-1464.

em Brock University, Canada


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This study explores 5 teachers' perspectives on inclusive education. The literature reviewed gives a historical background of special education as well as discusses a number of current methods and techniques that have been implemented as a means to include exceptional students in regular classroom settings. This is a qualitative study that collected and interpreted data in narrative form. Common themes emerged from the accounts that were shared by the participants. This study found that the understanding of mUltiple intelligences and differentiated instruction might assist a teacher to better meet the needs of exceptional students within inclusive classrooms. Based on this study, it is determined that a range of considerations needs to be weighed when choosing an educational placement for a student with an exceptionality. Each decision needs to be based on the individual student and the options open to himlher. When a decision about class placement is to be made, not only are the student's strengths and needs to be considered, but also the school and community, the teacher, and the parents' desire for their child must be taken into account. More work still needs to be done around inclusive education that is at the practical level, so that the needs of both the student and the teacher can be met. Inclusive education did not mean the same thing to each person. It was individualized, just as each student is an individual and what works best for himlher is individual. In learning about inclusive education, settings and strategies need to be considered to allow for each individual student to achieve hislher personal best.

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PreVi011.3 ':i or~ : indicat e('. tk~t ho t~)rE's sed ~-Al B 12 1i~2, ~' a semiconductor. r:Toreove r , the s i mpl.(~ electronic t heory also indi cates that ~ -AIB1 2 should be a semico nductor, since thf're is one nonbonding e 'Le ctrofl per AlB12- uni t. JPor these reasons, we decided to measure t he electrical n ropert i ~ s of ~ -AlB1 2 single crystal s . Singl e crystal s of¥- AIB 12 ab ou t 1 x 1 r1n1 . size were grown from a copper mel t at 12500 C. The melt technique coupled. 1,vi th slow cooling vilas used because of i ts advantages such as : siTYInle set- up of the expe rimon t ; only e ;l.sil y available c hemi cals are required and it i s a c omparatively strair::bt forvvard y,le t hod still yielding crystal s big enouGh for OtU' purpose . Copper rms used as a solvent , i nst8ad of previOl.wly used aluminum , because it allows c.l.'ystal growth at hig he r t emneratures. HovlGver, the cry s tals of ] -AlB12 shm'red very hi gh res i s t ance a t r oom temperature . From our neasureJ'lents we conclude that the r esistivity of j3- Al B12 is, at least, given as ~ = 4. x 107 oblD .em •• Those results are inc ons i s t ent wi 'uh the ones .. reported by IIiss Khin fo r bot- pressed j3-AlB12 g i ven a s = 7600 ohm . em . or I e s s . ' Since tbe hot pressing was done at about 800 - ' 9000C i n ~ rap hi te moul ds 1,7i th 97% AlB12- p oVJder, vie thi nk there is pas s ib i 1 i ty th a.t lower borides or borot] carbide are , being formed, ':.Jhich are k11 own to be good semiconductors . v7e tried to ro-pe r-AlB12 by addi'J,'?: agents s uch as l:Ig , IG.-InO 4. ' HgS04 , KI12PO 4·' etc. to t he melt .. However , all these re age 11 t eel either reduced the yield and size of t lJe crystals or r;ave crystals of high r esis'can ce again. We think tba t molten copper keeps t he i mpurities off . There is also a pos s i bil i ty t hc:!,t these doping agents get oxidi~::;ed at '1 250°C • Hence, we co ~ clud e that J -AIB12 has v~ ry high r es i stance at r oom temperature . This was a l s o C011 - fi rmed by checki ng the siYlgle and. polycrystals of .~-AIB12 from Norton Co., Ontario and Cooper Nletallurgical Association. Boron carbide has been reported to be a semiconductor with ~ - 0.3 to 0.8 ohm . cm. for hotpres sed s araples. Boron carbide b e inq: struct urally related to ¥-AIB12 , we de cided to study the electrical prone rties of it~ Single crystals. These crystals were cut from a Single melt grovvn crystal a t Norton Co., Ontario. The resistivity of th," se crystal s was measured by the Van der Pam-v' s ~ nethod, which \vas very c onvenient fo r our crystal sha-pp.s. Some of the crystals showed resistivity ~ == 0.50 ob,Tn.cr] . i n agreement with the previously reported results . However , a few crystals showed lower resistivity e.g . 0 .13 and 0.20 ohm.cra • • The Hall mobility could .not be measured and th8reiore i s lower than 0 .16 em 2 v - 1 sec -1 • This is in agreement \vith t he re1)orted Hall mobility for pyrolytic boron . _ 2 -1 -1 carbide as 0.13 cm v sec • We also studied the orientation of the boron carbide crystals by the Jjaue-method. The inclination of c-axis with res pect to x-ray be81Il was det ermined . This was found to be 100 t o 20° f or normal resistivity sarnples (0.5 ohm . cm.) and 27 - 30° for t he lower r esistivity samples (0.1 ~5 to 0.20 ohm.cm .). This indica tes the possibility that th.e r es if.1tivity of B13C3 i s orientation dependent.

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The optical response to far infrared radiation has been measured on a mosaic of heavy fermion CeColnssingle crystals. The superconducting transition temperature of the crystals has been determined by van der Pauw resistivity and ac-susceptibility measurements as Tc = 2.3 K. The optical measurements were taken above and below the transition temperature using a 3He cryostat and step and integrate Martin-Puplett type polarizing interferometer. The absolute reflectance of the heavy fermion CeColns in the superconducting state in range (0, 100)cm-1 was calculated from the measured thermal reflectance, using the normal state data of Singley et al and a low frequency extrapolation for a metallic material in the Hagen-Rubens regime. By means of Kramers-Kronig analysis the absolute reflectance was used to calculate the optical conductivity of the sample. The real part of the calculated complex conductivity 0-(w) ofCeColns indicates a possible opening of an energy gap close to 50 em-I.

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SiC and AtB 12 have been prepared and their resistivities and Hall voltages measured. The resistivities and Hall voltages were measured by the Van der Pauw's method, using spring loaded tungsten contacts. In this method, the major requirement is to have samples of plane parallel surfaces of arbitrary shape with four small contacts at the circumference. Similar measurements were made with a number of SiC crystals obtained from the Norton Research Corporation (Canada)-Ltd., Carolina Aluminum Co., Exolon Co. and Carborundum Co. It was found that resistivity, carrier concentration and mobility of ions depend on the type of impurity. AtB 12 was prepared from the melt containing At and B in the ratio of 4:1. They formed amber-colour pseudo tetragonal crystals. As the crystals obtained were small for electrical measurements, hot pressed lumps have been used to measure their resistivity.

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The cr ystal structure of the compound 2-benzoylethylidene-3-(2,4- dibromophenyl)-2,3-dihydro-5-phenyl-l,3,4-thiadiazole* C23H16Br2NZOS (BRMEO) has been determined by using three dimensiona l x-ray diffraction data. The crys tal form is monoclinic, space group P21/c, a = 17.492(4), o -.t' 0 R 0 b =: 16.979(1), c = 14.962(1) A, "X. =o= 90 ',= 106.46(1) , z = 8, graphite-monochromatized Mo~ rad iation, Jl= 0.710J3~, D = 1.62g/cc and o D = 1.65g/cc. The data were col lected on ~ Nonius CAD-4 c diffractometer. The following atoms were made anisotropic: Br, S, N, 0, C7, and C14-C16 for each i ndependent molecu le ; the rest were left isotropic. For 3112 independent refl ec tions with F > 6G\F), R == 0.057. The compound has two independent molecules within the asymmetric unit. Two different conformers were observed which pack well together. /l The S---O interaction distances of 2.493(6) and 2 . 478(7) A were observed for molecules A and B respectively. These values are consistent with earlier findings for 2-benzoylmethylene-3-(2,4-dibromophenyl)- ~~ 2,3-dihydro-5-phenyl-l,3,4-thiadiazole C22H14Br2N20S (BRPHO) and 2-benzoylpropylidene-3-(2,4-dibromophenyl)-2,3-dihydroiii ,'r 5-phenyl-l,3,4-thiadiazole C24H18Br2N20S (BRPETO ) where S---O distances are l ess than the van der Waals (3.251\) but greater than those expected for () a single bond (1.50A). From the results and the literature it appears obvious that the energy/reaction coordinate pathway has a minimum between the end structures (the mono- and bicyclic compounds). * See reference (21) for nomenclature.

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The x-ray crystal structure of thiamine hydroiodide,C1ZH18N40S12' has been determined. The unit cell parameters are a = 13.84 ± 0.03, o b = 7.44 ± 0.01, c = 20.24 ± 0.02 A, 8 = 120.52 ± 0.07°, space group P2/c, z = 4. A total of 1445 reflections having ,2 > 2o(F2), 26 < 40° were collected on a Picker four-circle diffractometer with MoKa radiation by the 26 scan technique. The structure was solved by the heavy atom method. The iodine and sulphur atoms were refined anisotropically; only the positional parameters were refined for the hydrogen atoms. Successive least squares cycles yielded an unweighted R factor of 0.054. The site of protonation of the pyrimidine ring is the nitrogen opposite the amino group. The overall structure conforms very closely to the structures of other related thiamine compounds. The bonding surrounding the iodine atoms is distorted tetrahedral. The iodine atoms make several contacts with surrounding atoms most of them at or near the van der Waal's distances A thiaminium tetrachlorocobaltate salt was produced whose molecular and crystal structure was j~dged to be isomorphous to thiaminium tetrachlorocadmate.

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The optical response to far infrared radiation has been measured on a mosaic of heavy fermion CeCoIns single crystals. The superconducting transition temperature of the crystals has been determined by van der Pauw resistivity and ac-susceptibility measurements as Tc = 2.3 K. The optical measurements were taken above and below the transition temperature using a ^He cryostat and step and integrate Martin-Puplett type polarizing interferometer. The absolute reflectance of the heavy fermion CeCoIns in the superconducting state in range (0, 100)cm~^ was calculated from the measured thermal reflectance, using the normal state data of Singley et al and a low frequency extrapolation for a metallic material in the Hagen-Rubens regime. By means of Kramers-Kronig analysis the absolute reflectance was used to calculate the optical conductivity of the sample. The real part of the calculated complex conductivity a{u)) of CeCoIns indicates a possible opening of an energy gap close to 50 cm~^.