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Start Over Author "White, Timothy A." Publisher american chemical society
65 results on '"White, Timothy A."'

2. Process Mass Intensity (PMI): A Holistic Analysis of Current Peptide Manufacturing Processes Informs Sustainability in Peptide Synthesis.

Author

Kekessie, Ivy, Wegner, Katarzyna, Martinez, Isamir, Kopach, Michael E., White, Timothy D., Tom, Janine K., Kenworthy, Martin N., Gallou, Fabrice, Lopez, John, Koenig, Stefan G., Payne, Philippa R., Eissler, Stefan, Arumugam, Balasubramanian, Li, Changfeng, Mukherjee, Subha, Isidro-Llobet, Albert, Ludemann-Hombourger, Olivier, Richardson, Paul, Kittelmann, Jörg, and Sejer Pedersen, Daniel

Published
2024
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13. Composition-tunable Zn(sub x)Cd(sub 1-x)Se nanocrystals with high luminescence and stability

Author

Xinhua Zhong, Mingyong Han, Zhili Dong, White, Timothy J., and Knoll, Wolfgang

Subjects
Zinc compounds -- Optical properties, Zinc compounds -- Chemical properties, Luminescence -- Research, Chemistry
Abstract

High-quality Zn(sub x)Cd(sub 1-x)Se nanocrystals were prepared at high temperature by incorporating stoichiometric amounts of Zn and Se into pre-prepared CdSe nanocrystals. A composition-tunable emission across most of the visible spectrum is demonstrated by a systematic blue-shift in emission wavelength.

Published
2003

17. Synthetic, Structural, and Mechanistic Issues in the Development of a Subtype Selective GABA Partial Agonist Hypnotic Agent

Author

Ragan, John A., primary, Murry, Jerry A., additional, Castaldi, Michael J., additional, Conrad, Alyson K., additional, Hill, Paul D., additional, Jones, Brian P., additional, Kasthurikrishnan, Narasimhan, additional, Li, Bryan, additional, Makowski, Teresa W., additional, McDermott, Ruth, additional, Sitter, Barb J., additional, White, Timothy D., additional, and Young, Gregory R., additional

Published
2003
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19. Green Chemistry Articles of Interest to the Pharmaceutical Industry.

Author

Diaz Rodriguez, Alba, Dalton, Charlotte, Diorazio, Louis, Doerfler, Jaika, Engl, Oliver D., Hickey, Matthew, Howell, Gareth, Hutchby, Marc, Latham, Jonathan, Li, Wei, Munday, Rachel, Richardson, Paul, Roosen, Philipp C., Steven, Alan, Terrett, Jack A., Treitler, Daniel S., White, Timothy, and Zeng, Mingshuo

Published
2020
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21. Light-driven reversible handedness inversion in self-organized helical superstructures

Author

Mathews, Manoj, Zola, Rafael S., Hurley, Shawn, Deng-Ke Yang, White, Timothy J., Bunning, Timothy J., and Quan Li

Subjects
Azo compounds -- Structure, Azo compounds -- Chemical properties, Benzene -- Structure, Benzene -- Chemical properties, Chemistry
Abstract

The article explains the various mechanisms that are involved in the fast-photon-mode reversible handedness inversion of different self-organized helical superstructures. The two light-driven cyclic azobenzenophanes observed in the study are shown to exhibit extremely high solubility and helical twisting power.

Published
2010

32. Phototropic Guest-Host Liquid Crystal Systems: Environmental Effects on Naphthopyran Kinetics.

Author

Rumi, Mariacristina, White, Timothy J., and Bunning, Timothy J.

Subjects
*PHASE transitions, *ISOTHERMAL processes, *PYRAN derivatives, *LIQUID crystals, *PHOTOTROPISM (Chemistry), *CHEMICAL kinetics
Abstract

Photoinduced isothermal and order-increasing phase transitions can be observed in guest-host liquid crystal mixtures containing naphthopyran derivatives. The changes are attributed to the different geometry and a less energetically favorable interaction with the liquid crystal molecules for the ground state naphthopyran species with respect to the photoproduct. In this study, we have investigated the thermal relaxation of the naphthopyran photoproduct back to the initial species as a function of temperature and excitation conditions. It was found that the thermal relaxation is typically first-order and its characteristic rate has a temperature dependence that is different in the anisotropic and isotropic states of the mesogenic solvents. In particular, the activation energy for thermal relaxation is larger in the ordered phases of mesogenic solvents relative to their isotropic phase. The findings suggests that the naphthopyran relaxation is hindered by the organization of the host environment. These results will be useful to build a more complete understanding of the mutual guest-host interactions in naphthopyran-containing guest-host LC systems. [ABSTRACT FROM AUTHOR]

Published
2016
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33. Structure and Surface Reactivity of WO42-, SO42-, PO43- Modified Ca-Hydroxyapatite Catalysts and Their Activity in Ethanol Conversion

Author

Ramesh, Kanaparthi, Ling, Eileen Goh Yi, Gwie, C G, White, Timothy, Borgna, Armando, Ramesh, Kanaparthi, Ling, Eileen Goh Yi, Gwie, C G, White, Timothy, and Borgna, Armando

Abstract

In the current study, we have synthesized calcium hydroxyapatite (CaHAP) from different phosphorus sources namely, NH4H2PO4 and H3PO4. The structure of CaHAP was confirmed by XRD, FT-IR, and Raman characterization methods. The CaHAP was further modified with various anions such as WO42-, SO42-, and PO43- with fixed content of 10 wt %. To understand the textural and structural properties, these samples were thoroughly characterized by N2 physisorption, X-ray diffraction, Fourier transform infrared, Raman and thermogravimetry-differential thermal analysis methods. Ethanol adsorption at various temperatures was studied in detail using diffuse reflectance Fourier transform spectroscopic to unravel the formation and stability of surface species and the interaction of ethanol with CaHAP. The temperature programmed desorption of ethanol (ethanol-TPD) was performed to understand the stability, surface reactivity, and product distribution. The catalytic activity of the above catalysts was tested in ethanol conversion over a temperature range of 300-450 °C.

Published
2012

34. Hydroxyapatite Foam as a Catalyst for Formaldehyde Combustion at Room Temperature

Author

Xu, Jing, White, Timothy, Li, Ping, He, Chongheng, Han, Yi-Fan, Xu, Jing, White, Timothy, Li, Ping, He, Chongheng, and Han, Yi-Fan

Abstract

The excellent performance of hydroxyapatite, a novel non-precious metal catalyst, for formaldehyde (HCHO) combustion at room temperature is reported. Temperature-programmed surface reaction results indicated that hydroxyl groups bonded with the channel Ca2+ may be responsible for adsorption/activation of HCHO.

Published
2011

35. Microwave Synthesis of Noncentrosymmetric BaTiO 3 Truncated Nanocubes for Charge Storage Applications

Author

Swaminathan, V, Pramana, Stevin S, White, Timothy, Chen, L, Chukka, Rami, Ramanujan, R V, Swaminathan, V, Pramana, Stevin S, White, Timothy, Chen, L, Chukka, Rami, and Ramanujan, R V

Abstract

Truncated nanocubes of barium titanate (BT) were synthesized using a rapid, facile microwave-assisted hydrothermal route. Stoichiometric composition of pellets of nanocube BT powders was prepared by two-stage microwave process. Characterization by powder

Published
2010

36. Biphasic Pd-Au alloy catalyst for low-temperature CO oxidation

Author

Xu, Jing, White, Timothy, Li, Ping, He, Chongheng, Yu, Jianguo, Yuan, Weikang, Han, Yi-Fan, Xu, Jing, White, Timothy, Li, Ping, He, Chongheng, Yu, Jianguo, Yuan, Weikang, and Han, Yi-Fan

Abstract

Low-temperature CO oxidation over a compositional series of Pd-Au nanoalloy catalysts supported on silica fume was studied. Except for the pure metals, these materials invariably showed biphasic separation into palladium- and gold-rich components. Performance was optimal for a catalyst of bulk composition Pd4Au1, a mixture of Pd90Au10 (72.5 at. %) and Pd31Au69 (27.5 at. %), that was remarkably active at 300 K and more stable than a pure Au catalyst. For bulk materials dominated by Pd (Pd:Au = 16:1; 8:1; 4:1), the palladium-rich alloy fraction frequently adopted hollow sphere or annular morphology, while the gold-rich crystals were often multiply twinned. Quantitative powder X-ray diffraction (XRD) showed that under the synthesis conditions used, the Au solubility limit in Pd crystals was ∼12 at. %, while Pd was more soluble in Au (∼31 at. %). This was consistent with X-ray photoelectron spectroscopy (XPS), which revealed that the surfaces of Pd-rich alloys were enriched in gold relative to the bulk composition. In situ Fourier transform infrared spectra collected during CO oxidation contained a new band at 2114 cm-1 (attributed to linear CO-Au/Au-Pd bonds) and reduced intensity of a band at 2090 cm-1 (arising from a linear CO-Pd bond) with escalating Au content, indicating that the Pd sites became increasingly obscured by Au. High-resolution electron micrographs (HRTEM) of the Pd-rich alloys revealed atomic scale surface defects consistent with this interpretation. These results demonstrate that gold-containing biphasic Pd nanoalloys may be highly durable alternatives for a range of catalytic reactions.

Published
2010

37. Development and Manufacturing GMP Scale-Up of a Continuous Ir-Catalyzed Homogeneous Reductive Amination Reaction.

Author

May, Scott A., Johnson, Martin D., Buser, Jonas Y., Campbell, Alison N., Frank, Scott A., Haeberle, Brian D., Hoffman, Philip C., Lambertus, Gordon R., McFarland, Adam D., Moher, Eric D., White, Timothy D., Hurley, D. Declan, Corrigan, Aoife P., Gowran, Olivia, Kerrigan, Niall G., Kissane, Marie G., Lynch, Regina R., Sheehan, Paul, Spencer, Richard D., and Pulley, Shon R.

Published
2016
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40. Green Chemistry Articles of Interest to the Pharmaceutical Industry.

Author

Bandichhor, Rakeshwar, Bhattacharya, Apurba, Cosbie, Andrew, Diorazio, Louis, Dunn, Peter, Fraunhoffer, Kenneth, Gallou, Fabrice, Hayler, John, Hickey, Matthew, Hinkley, Bill, Humphreys, Luke, Kaptein, Bernard, Oh, Lynette, Richardson, Paul, Roberts, Scott, White, Timothy, Wuyts, Stijn, and Jingjun Yin

Published
2015
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43. The GreenChemistry Articles of Interest.

Author

Bandichhor, Rakeshwar, Bhattacharya, Apurba, Diorazio, Louis, Dunn, Peter, Fraunhoffer, Kenneth, Gallou, Fabrice, Hayler, John, Hickey, Matthew, Hinkley, Bill, Hughes, David, Humphreys, Luke, Kaptein, Bernard, Mathew, Suju, Oh, Lynnette, Richardson, Paul, White, Timothy, and Wuyts, Stijn

Published
2014
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45. Green Chemistry Articlesof Interest to the PharmaceuticalIndustry.

Author

Bandichhor, Rakeshwar, Bhattacharya, Apurba, Diorazio, Louis, Dunn, Peter, Fraunhoffer, Kenneth, Gallou, Fabrice, Hayler, John, Hickey, Matthew, Hinkley, Bill, Hughes, David, Humphreys, Luke, Janocha, Bernd, Kaptein, Bernard, Mathew, Suju, Rammeloo, Thomas, Richardson, Paul, and White, Timothy

Published
2012
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47. Photochemical Mechanismand Photothermal Considerations in the Mechanical Response of Monodomain,Azobenzene-Functionalized Liquid Crystal Polymer Networks.

Author

Lee, Kyung Min and White, Timothy J.

Subjects
*PHOTOMECHANICAL processes, *PHOTOCHEMISTRY, *POLYMER liquid crystals, *AZOBENZENE, *SPECTRUM analysis, *POLYMER networks, *FLUID mechanics
Abstract

The potential for wireless transduction of input lightenergy into mechanical outputs has led to a reinvigorated pursuitof photomechanical effects in polymeric materials and composites.We report here on factors influencing the photochemical mechanism(and thus the mechanical output) in monodomain azobenzene-functionalizedliquid crystal polymer networks. Through systematic examination ofa representative material with both mechanics and spectroscopic characterizationthe prevalence of the trans–cis and trans–cis–transmechanisms is elucidated. Furthermore, the role of light intensityin generating heat (photothermal effects) is also reported. [ABSTRACT FROM AUTHOR]

Published
2012
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49. Green Chemistry Articles of Interest to the Pharmaceutical Industry.

Author

Amarnath, L., Andrews, Ian, Bandichhor, Rakeshwar, Bhattacharya, Apurba, Dunn, Peter, Hayler, John, Hinkley, William, Holub, Nicole, Hughes, David, Humphreys, Luke, Kaptein, Bernard, Krishnen, Hare, Lorenz, Kurt, Mathew, Suju, Nagaraju, G., Rammeloo, Thomas, Richardson, Paul, Wang, Lijun, Wells, Andrew, and White, Timothy

Published
2012
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