Crystal growth, characterization and point contact spectroscopy on CuxTiSe₂

Various s e t s of single c rys t a l s and poly c rys t a l s of Cux TiSe2 were grown. X- r ay diffraction and ene rgy dispersive spe c t ros copy r e sul t s verified tha t the c rys t a l s were the cor r e c t compos i t ion and c rys t a l s t ruc tur e . Re s i s t ivi ty me a sur ement s and magne t i c sus c ept ibi l i ty me a sur ement s de t e rmined the supe r conduc t ing t r ans i t ion t empe r a tur e s for the c rys t a l s . The c rys t a l s in each growth had various supe r conduc t ing t r ans i t ion t empe r a tur e s . Also, the me a sur ement s indi c a t ed tha t the c rys t a l s were inhomogeneous. Point cont a c t spe c t ros copy expe r iment s were employed on various single c rys t a l s . Inspe c t ion of the da t a indi c a t ed tha t the ma t e r i a l ha s a single ene rgy gap . A progr am was bui l t ut i l i z ing the Levenbe rg-Ma rqua rdt me thod and theory on point cont a c t spe c t ros copy to de t e rmine the supe r conduc t ing ene rgy gap. Plot s of the supe r conduc t ing ene rgy gap a t various t empe r a tur e s were in di s agr e ement wi th wha t was expe c t ed for a convent iona l supe r conduc tor .

Infrared Spectroscopy of Gadolinium

Measurements of the optical reflectivity of the normal incident light along c-axis [0001] have been made on a Gadolinium single crystal, for temperatures between 50 K and room temperature just above the Curie temperature of Gd, which is 293 K. And covering the spectrum range between 100 -11000 cm-I . This work is the first study of Gd in the far infrared range. In fact it fills the gap below 0.2 eV which has never been measured before. Extreme attention was paid to the fact that Gadolinium is a very reactive metal with air. Thus, the sample was mechanically polished and carefully handled during the measurement. However, temperature dependent optical measurements have been made in the same frequency range for a sample of Gd2O3. For comparison, both samples of Gd and Gd2O3 were examined by X-Ray diffraction. XRD analysis showed that the sample was pure gadolinium and the oxide layer either does not exist, or is very thin. Furthermore, this fact was supported by the absence of any of Gd2O3 features in the Gd sample reflectivity. Kramers Kronig analysis was applied to extract the optical functions from the reflectance data. The optical conductivity shows a strong temperature dependence feature in the mid-infrared. This feature disappears completely at room temperature which supports a magnetic origin.

William Hamilton Merritt Welland Canal circular, July 12, 1823

William Hamilton Merritt (1793-1862) was a soldier, merchant, and politician who was instrumental in the promotion and development of the Welland Canal. After serving with the Lincoln militia during the War of 1812, Merritt became a merchant in St. Catharines, and purchased some land on Twelve Mile Creek on which he ran a sawmill and constructed a grist mill. He initially envisioned a canal between the Welland River and Twelve Mile Creek, which evolved into a plan to link Lake Ontario and Lake Erie. This would enable goods from western Canada to be conveniently shipped to Montreal and Great Britain through the St. Lawrence, while bypassing the Niagara portage. His plan met with opposition for financial and political reasons, as well as from those along the Niagara portage whose businesses would suffer if the canal were built. Despite this opposition, the Welland Canal Company was chartered by the Upper Canadian assembly in January, 1824. Construction on the canal began later that year, and was completed in 1829.

Transient and Pulsed Electron Paramagnetic Resonance Spectroscopy on Type I Photosynthetic Reaction Centers

Two time-resolved EPR techniques, have been used to study the light induced electron transfer(ET) in Type I photosynthetic reaction centers(RCs). First, pulsed EPR was used to compare PsaA-M688H and PsaB-M668H mutants of Chlamydomonas reinhardtii and Synechosystis sp. PCC 6803.The out-of-phase echo modulation curves combined with other EPR and optical data show that the effect of the mutations is species dependent. Second, transient and pulsed EPR data are presented which show that PsaA-A660N and PsaB-A640N mutations in C. reinhardtii alter the relative quantum yield of ET in the A- and B-branches of PS I. Third, transient EPR studies on RCs from Heliobacillus mobilis that have been exposed to oxygen show partial inhibition of ET. In the RCs in which ET still occurs, the ET kinetics and EPR spectra show evidence of oxidation of some but not all of the, BChl g and BChl g' to Chl a.

William Hamilton Merritt Welland Canal circular, July 12, 1823

William Hamilton Merritt (1793-1862) was a soldier, merchant, and politician who was instrumental in the promotion and development of the Welland Canal. After serving with the Lincoln militia during the War of 1812, Merritt became a merchant in St. Catharines, and purchased some land on Twelve Mile Creek on which he ran a sawmill and constructed a grist mill. He initially envisioned a canal between the Welland River and Twelve Mile Creek, which evolved into a plan to link Lake Ontario and Lake Erie. This would enable goods from western Canada to be conveniently shipped to Montreal and Great Britain through the St. Lawrence, while bypassing the Niagara portage. His plan met with opposition for financial and political reasons, as well as from those along the Niagara portage whose businesses would suffer if the canal were built. Despite this opposition, the Welland Canal Company was chartered by the Upper Canadian assembly in January, 1824. Construction on the canal began later that year, and was completed in 1829

Electron Transfer Involving the Phylloquinone (A1) Cofactor of Photosystem I Examined with Time Resolved Absorbance and Electron Paramagnetic Resonance Spectroscopy

The dependence of the electron transfer (ET) rate on the Photosystem I (PSI) cofactor phylloquinone (A1) is studied by time-resolved absorbance and electron paramagnetic resonance (EPR) spectroscopy. Two active branches (A and B) of electron transfer converge to the FX cofactor from the A1A and A1B quinone. The work described in Chapter 5 investigates the single hydrogen bond from the amino acid residue PsaA-L722 backbone nitrogen to A1A for its effect on the electron transfer rate to FX. Room temperature transient EPR measurements show an increase in the rate for the A1A- to FX for the PsaA-L722T mutant and an increased hyperfine coupling to the 2-methyl group of A1A when compared to wild type. The Arrhenius plot of the A1A- to FX ET in the PsaA-L722T mutant suggests that the increased rate is probably the result of a slight change in the electronic coupling between A1A- and FX. The reasons for the non-Arrhenius behavior are discussed. The work discussed in Chapter 6 investigates the directionality of ET at low temperature by blocking ET to the iron-sulfur clusters FX, FA and FB in the menB deletion mutant strain of Synechocyctis sp. PCC 6803, which is unable to synthesize phylloquinone, by incorporating the high midpoint potential (49 mV vs SHE) 2,3-dichloro-1,4-naphthoquinone (Cl2NQ) into the A1A and A1B binding sites. Various EPR spectroscopic techniques were implemented to differentiate between the spectral features created from A and B- branch electron transfer. The implications of this result for the directionality of electron transfer in PS I are discussed. The work discussed in Chapter 7 was done to study the dependence of the heterogeneous ET at low temperature on A1 midpoint potential. The menB PSI mutant contains plastiquinone-9 in the A1 binding site. The solution midpoint potential of the quinone measures 100 mV more positive then wild-type phylloquinone. The irreversible ET to the terminal acceptors FA and FB at low temperature is not controlled by the forward step from A1 to FX as expected due to the thermodynamic differences of the A1 cofactor in the two active branches A and B. Alternatives for the ET heterogeneity are discussed.

El cura del Sagrario de Querétaro, refuta un folleto, que con el título: Lo que creen los protestantes ha hecho circular en esta ciudad, Mr. Almon W. Greeman, ministro protestante de la iglesia llamada Evangélica

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Relación que en apoyo de la representación en contra de la circular de 17 de enero próximo pasado presenta al Supremo Gobierno, el ciudadano Pedro Vander-Linden.

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Comunicación circular que el Exmo. Sr. Don Manuel de la Peña y Peña, estendió en el año de 1845, como ministro de relaciones, para dirigirla a los gobiernos y asambleas de partamentales, sobre la cuestión de paz o guerra, según el estado que guardaban en aquella época

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Circular expedida por el C. Licenciado Protasio P. Tagle, Ministro de Gobernación, en que se dan a conocer las negociaciones entabladas con el C. Lic. José María Iglesias, para dar término a la guerra civil, y que fueron rotas por su parte

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Circular del Ilmo. Sr. Doctor Don Cresencio Carrillo y Ancona Obispotitular de Lero y Coadjutor de Yucatán sobre la coronación de Ntra.Sra. de Guadalupe y sobre el jubileo sacerdotal de su Santidad el Señor León XIII y de su Señoría Ilustrisíma Dignísi

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Circular sobre la sagrada predicación

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Circular Diocesana, expedida por el Ilmo. Sr. Obispo de Cuernavaca,con motivo de la función que esta Sagrada Mitra celebrará en la Colegiata de Guadalupe...

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Circular dirigida por el Ilmo. Sr. Arzobispo de México al Ilmo. y Ve. Cabildo Metropolitano, al de la insigne Colegiata de Guadalupe, al clero secular y regular y a todos sus diocesanos

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Circular diocesana expedida por el Ilmo. Sr. Obispo de Cuernavaca, con motivo de la declaración del Exmo. y Rmo. Sr. visitador apostólico acerca de la conducta que debe observar la prensa católica.

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