Roger Bartholomew - Academia.edu (original) (raw)
Papers by Roger Bartholomew
Journal of Crystal Growth, 1970
The Magneli phases (ri,,0 2_1) and Ti305 can be grown from limits. Different compounds can be obt... more The Magneli phases (ri,,0 2_1) and Ti305 can be grown from limits. Different compounds can be obtained by adjusting Poz Na2B4O7-B203 fluxes under equilibrium conditions ifthe oxygen over a narrow range. fugacity ofthe coexisting vapor phase is controlled within narrow I. Infrodoetlon Temperature,°c
Optical Amplifiers and Their Applications, 1992
The efficiency of Pr-doped fluorozirconate amplifiers at 1300 nm are limited by nonradiative deca... more The efficiency of Pr-doped fluorozirconate amplifiers at 1300 nm are limited by nonradiative decay. The Pr3+ 1G4 excited state lifetime has been measured in a mixed halide glass to be 2.7 times longer than the lifetime in a fluorozirconate host. The longer lifetime denotes a comparable reduction in the nonradiative decay rate.
PROBLEM TO BE SOLVED: To immobilize plural organics wherein the size of water and molecule change... more PROBLEM TO BE SOLVED: To immobilize plural organics wherein the size of water and molecule changes by using such porous substance as specific compound such as inorganic binder, zeolite, and porous silica, etc., is consolidated as a getter to water and organic molecule in a high power laser seal-up vessel. SOLUTION: A high power laser 6' allocated in a high-power laser seal-up vessel 10 is fixed to a substrate 2, while a waveguide fiber 4 which combined laser light to a photo-detecting device provided, and a getter 8 is stuck to the inside surface at upper part of the seal-up vessel 10 as a thin slab. The material of the getter 8 is inorganic binder, an arbitrary one among zeolite types, etc., which have such bore size or channel size as suitable for immobilizing water, a couple of these compounds, porous silica, etc., comprising such bore size or channel size as immobilizing large organic molecule, and couple of compounds. These are consolidated to obtain a porous body.
PURPOSE: To form an undamaged surface by heat-treating and consolidating a porous glass having in... more PURPOSE: To form an undamaged surface by heat-treating and consolidating a porous glass having interconnective micropores to which a dopant dissolved in organic solvent without any OH group is added. CONSTITUTION: The salt of a dopant (for example, germanium, phosphor, fluorine, and bromine) is dissolved in organic solvent (ketone, acetone or the like) without any OH group. A porous glass preform 32 having interconnective micropores is immersed into this solvent 33, and then the solvent is removed. Next, the preform 32 to which this dopant is dispersed is heat treated and consolidated for forming a non-porous glassy body at least one part of which the dopant is dispersed on. Thus, the 0H containing solvent which is likely to cause crack and/or flaking on the outer surface of the preform 32 after a drying process is not used so that the undamaged surface of the glassy body can be formed. COPYRIGHT: (C)1992,JPO
High gain amplification has been demonstrated at 1310 nm with a Pr-doped fluorozirconate fiber [1... more High gain amplification has been demonstrated at 1310 nm with a Pr-doped fluorozirconate fiber [1], but with a much lower pump efficiency than a comparable Er-doped silica amplifier at 1550 nm. This low pump efficiency is attributable to the low quantum efficiency of the lG4->3H5 transition of Pr3+ [2], which follows from the preponderance of multiphonon mediated decay from the 1G4 to the nearby 3F4 level. The probability of multiphonon decay between two energy levels is inversely related to the number of phonons required to bridge the energy gap. Therefore, the lowering of this probability and an improvement in the quantum efficiency would be expected through the use of a host material with lower phonon energies. In addition, an improvement in the quantum efficiency also would be expected in those materials with larger lG4->3H5 radiative rates. Over the last year a number of potentially more efficient host glasses have been reported [3,4,5,7]. Here we consider two of these, t...
PURPOSE: To obtain a ceramic material suitable for producing ceramic capacitor having temp. indep... more PURPOSE: To obtain a ceramic material suitable for producing ceramic capacitor having temp. independent capacitance characteristic, small dielectric loss tangent and large dielectric constant by forming from a specific metal multiple oxide containing Bi. CONSTITUTION: The multiple oxide expressed by (I) (Bi 2 O 2 ) 2+ (A m-1 B m O 3m+1 ) 2- , (II) (Bi 2 O 2 ) 2+ (A m-1 B m Mn γ O 3m+δ+1 ) 2- and (III) (Bi 2 O 2 ) 2+ (A m-1 B m Zr β O 3m+δ+1 ) 2- (m>1, each of (β), (γ) and (δ)>0, A represents Na, K, Ca, Sr, Ba, Bi or Pb, B represents Nb, Ta or Tl and at least one part thereof is substituted by a mixed ion such as C 1/3 2+ D 2/3 5+ (C 2+ represents Mg 2+ , Zn 2+ , Ni 2+ , Co 2+ , Cu 2+ or Cd 2+ , D 5+ ion represents Nb 5+ or Ta 5+ )) is used as the ceramic material having smaller temp. coefficient of capacitance at -55°C to 125°C in 1 kHz to 1 MHz than that measures at room temp. and exhibiting dielectric constant of ≥105 measured at room temp. (in 1 kHz to 1 MHz). COPYRIGHT: (C...
J. Chem. Soc. C, 1971
Irradiation of oxygenated solutions of triethylamine, di-n-propylamine, and n-propylamine, contai... more Irradiation of oxygenated solutions of triethylamine, di-n-propylamine, and n-propylamine, containing xanthone, fluorenone, p-aminobenzophenone, and methyl β-naphthyl ketone, results in the amines being oxidised. The reactions are interpreted as occurring by initial hydrogen abstraction from the amine by the excited ketone, to give radicals of the amines which subsequently react with oxygen to give the observed products.
Journal of Inorganic and Nuclear Chemistry, 1969
Journal of the Chemical Society D: Chemical Communications, 1970
Quantum yields of product formation and amine disappearance 35. 2.1.2. Discussion. 36. Reaction o... more Quantum yields of product formation and amine disappearance 35. 2.1.2. Discussion. 36. Reaction of singlet oxygen quenchers. 36. Quantum yields. 37. Correlation with reduction. 37. Competition between hydrogen abstraction and oxygen quenching. 3 8. Relative rates of photo-oxidation. 39. The formation of products. 42. The cyclic action of the sensitiser. 44.
Journal of the Chemical Society, Perkin Transactions 2, 1972
Triphenylamine and tri-p-tolylamine quench the photoreduction of benzophenone by diphenylmethanol... more Triphenylamine and tri-p-tolylamine quench the photoreduction of benzophenone by diphenylmethanol and in the case of triphenylamine, the quenching effect is substantially increased by a change of solvent from benzene to acetonitrile. Flash photolysis of nitrogen-flushed acetonitrile solutions of tri-p-tolylamine containing benzo-phenone, produced the amine radical cation and the radical anion of the ketone. When oxygenated solutions of either the amine alone of amine plus benzophenone were flash-photolysed, only the radical cation of the amine was observed. The lifetime and concentration of the radical cation is increased as the concentration either of oxygen or of benzophenone is increased. One of the modes of decay of the radical cation appears to be reaction with tri-p-tolylamine and a rate constant of 3·5 × 103 l mol–1 s–1 was determined for this process. Nitrogen-flushed acetonitrile solutions of triphenylamine gave, on flash photolysis, an intermediate (λmax. 610 nm) identified, from previous work, as cyclisation product, whereas when benzophenone is present in solution, the amine radical cation is produced. These results support the conclusion that tertiary aromatic amines can donate an electron to triplet benzophenone, and lend some credence to the previous postulate that amines react with triplet ketones by an electron-transfer process.
Journal of the Chemical Society C: Organic, 1971
Product studies are reported on the benzophenone-sensitised photo-oxidation of primary, secondary... more Product studies are reported on the benzophenone-sensitised photo-oxidation of primary, secondary, and tertiary aliphatic amines and N-alkylanilines. Aliphatic amines gave aldehydes and imines, whereas N-alkylanilines were dealkylated but did not give imines. Amines which are known physical quenchers of singlet oxygen were efficiently oxidised. The reactivity of these compounds, and the type of products formed in the reaction, are explainable in terms of a mechanism in which hydrogen atom abstraction from the amine by triplet ketone is the primary chemical reaction. The results are not in accord with the participation of singlet oxygen. Quantum yield measurements of oxygen uptake, amine disappearance, and product formation are consistent with the proposed mechanism.
Chemischer Informationsdienst, 1972
Journal of Crystal Growth, 1970
The Magneli phases (ri,,0 2_1) and Ti305 can be grown from limits. Different compounds can be obt... more The Magneli phases (ri,,0 2_1) and Ti305 can be grown from limits. Different compounds can be obtained by adjusting Poz Na2B4O7-B203 fluxes under equilibrium conditions ifthe oxygen over a narrow range. fugacity ofthe coexisting vapor phase is controlled within narrow I. Infrodoetlon Temperature,°c
Optical Amplifiers and Their Applications, 1992
The efficiency of Pr-doped fluorozirconate amplifiers at 1300 nm are limited by nonradiative deca... more The efficiency of Pr-doped fluorozirconate amplifiers at 1300 nm are limited by nonradiative decay. The Pr3+ 1G4 excited state lifetime has been measured in a mixed halide glass to be 2.7 times longer than the lifetime in a fluorozirconate host. The longer lifetime denotes a comparable reduction in the nonradiative decay rate.
PROBLEM TO BE SOLVED: To immobilize plural organics wherein the size of water and molecule change... more PROBLEM TO BE SOLVED: To immobilize plural organics wherein the size of water and molecule changes by using such porous substance as specific compound such as inorganic binder, zeolite, and porous silica, etc., is consolidated as a getter to water and organic molecule in a high power laser seal-up vessel. SOLUTION: A high power laser 6' allocated in a high-power laser seal-up vessel 10 is fixed to a substrate 2, while a waveguide fiber 4 which combined laser light to a photo-detecting device provided, and a getter 8 is stuck to the inside surface at upper part of the seal-up vessel 10 as a thin slab. The material of the getter 8 is inorganic binder, an arbitrary one among zeolite types, etc., which have such bore size or channel size as suitable for immobilizing water, a couple of these compounds, porous silica, etc., comprising such bore size or channel size as immobilizing large organic molecule, and couple of compounds. These are consolidated to obtain a porous body.
PURPOSE: To form an undamaged surface by heat-treating and consolidating a porous glass having in... more PURPOSE: To form an undamaged surface by heat-treating and consolidating a porous glass having interconnective micropores to which a dopant dissolved in organic solvent without any OH group is added. CONSTITUTION: The salt of a dopant (for example, germanium, phosphor, fluorine, and bromine) is dissolved in organic solvent (ketone, acetone or the like) without any OH group. A porous glass preform 32 having interconnective micropores is immersed into this solvent 33, and then the solvent is removed. Next, the preform 32 to which this dopant is dispersed is heat treated and consolidated for forming a non-porous glassy body at least one part of which the dopant is dispersed on. Thus, the 0H containing solvent which is likely to cause crack and/or flaking on the outer surface of the preform 32 after a drying process is not used so that the undamaged surface of the glassy body can be formed. COPYRIGHT: (C)1992,JPO
High gain amplification has been demonstrated at 1310 nm with a Pr-doped fluorozirconate fiber [1... more High gain amplification has been demonstrated at 1310 nm with a Pr-doped fluorozirconate fiber [1], but with a much lower pump efficiency than a comparable Er-doped silica amplifier at 1550 nm. This low pump efficiency is attributable to the low quantum efficiency of the lG4->3H5 transition of Pr3+ [2], which follows from the preponderance of multiphonon mediated decay from the 1G4 to the nearby 3F4 level. The probability of multiphonon decay between two energy levels is inversely related to the number of phonons required to bridge the energy gap. Therefore, the lowering of this probability and an improvement in the quantum efficiency would be expected through the use of a host material with lower phonon energies. In addition, an improvement in the quantum efficiency also would be expected in those materials with larger lG4->3H5 radiative rates. Over the last year a number of potentially more efficient host glasses have been reported [3,4,5,7]. Here we consider two of these, t...
PURPOSE: To obtain a ceramic material suitable for producing ceramic capacitor having temp. indep... more PURPOSE: To obtain a ceramic material suitable for producing ceramic capacitor having temp. independent capacitance characteristic, small dielectric loss tangent and large dielectric constant by forming from a specific metal multiple oxide containing Bi. CONSTITUTION: The multiple oxide expressed by (I) (Bi 2 O 2 ) 2+ (A m-1 B m O 3m+1 ) 2- , (II) (Bi 2 O 2 ) 2+ (A m-1 B m Mn γ O 3m+δ+1 ) 2- and (III) (Bi 2 O 2 ) 2+ (A m-1 B m Zr β O 3m+δ+1 ) 2- (m>1, each of (β), (γ) and (δ)>0, A represents Na, K, Ca, Sr, Ba, Bi or Pb, B represents Nb, Ta or Tl and at least one part thereof is substituted by a mixed ion such as C 1/3 2+ D 2/3 5+ (C 2+ represents Mg 2+ , Zn 2+ , Ni 2+ , Co 2+ , Cu 2+ or Cd 2+ , D 5+ ion represents Nb 5+ or Ta 5+ )) is used as the ceramic material having smaller temp. coefficient of capacitance at -55°C to 125°C in 1 kHz to 1 MHz than that measures at room temp. and exhibiting dielectric constant of ≥105 measured at room temp. (in 1 kHz to 1 MHz). COPYRIGHT: (C...
J. Chem. Soc. C, 1971
Irradiation of oxygenated solutions of triethylamine, di-n-propylamine, and n-propylamine, contai... more Irradiation of oxygenated solutions of triethylamine, di-n-propylamine, and n-propylamine, containing xanthone, fluorenone, p-aminobenzophenone, and methyl β-naphthyl ketone, results in the amines being oxidised. The reactions are interpreted as occurring by initial hydrogen abstraction from the amine by the excited ketone, to give radicals of the amines which subsequently react with oxygen to give the observed products.
Journal of Inorganic and Nuclear Chemistry, 1969
Journal of the Chemical Society D: Chemical Communications, 1970
Quantum yields of product formation and amine disappearance 35. 2.1.2. Discussion. 36. Reaction o... more Quantum yields of product formation and amine disappearance 35. 2.1.2. Discussion. 36. Reaction of singlet oxygen quenchers. 36. Quantum yields. 37. Correlation with reduction. 37. Competition between hydrogen abstraction and oxygen quenching. 3 8. Relative rates of photo-oxidation. 39. The formation of products. 42. The cyclic action of the sensitiser. 44.
Journal of the Chemical Society, Perkin Transactions 2, 1972
Triphenylamine and tri-p-tolylamine quench the photoreduction of benzophenone by diphenylmethanol... more Triphenylamine and tri-p-tolylamine quench the photoreduction of benzophenone by diphenylmethanol and in the case of triphenylamine, the quenching effect is substantially increased by a change of solvent from benzene to acetonitrile. Flash photolysis of nitrogen-flushed acetonitrile solutions of tri-p-tolylamine containing benzo-phenone, produced the amine radical cation and the radical anion of the ketone. When oxygenated solutions of either the amine alone of amine plus benzophenone were flash-photolysed, only the radical cation of the amine was observed. The lifetime and concentration of the radical cation is increased as the concentration either of oxygen or of benzophenone is increased. One of the modes of decay of the radical cation appears to be reaction with tri-p-tolylamine and a rate constant of 3·5 × 103 l mol–1 s–1 was determined for this process. Nitrogen-flushed acetonitrile solutions of triphenylamine gave, on flash photolysis, an intermediate (λmax. 610 nm) identified, from previous work, as cyclisation product, whereas when benzophenone is present in solution, the amine radical cation is produced. These results support the conclusion that tertiary aromatic amines can donate an electron to triplet benzophenone, and lend some credence to the previous postulate that amines react with triplet ketones by an electron-transfer process.
Journal of the Chemical Society C: Organic, 1971
Product studies are reported on the benzophenone-sensitised photo-oxidation of primary, secondary... more Product studies are reported on the benzophenone-sensitised photo-oxidation of primary, secondary, and tertiary aliphatic amines and N-alkylanilines. Aliphatic amines gave aldehydes and imines, whereas N-alkylanilines were dealkylated but did not give imines. Amines which are known physical quenchers of singlet oxygen were efficiently oxidised. The reactivity of these compounds, and the type of products formed in the reaction, are explainable in terms of a mechanism in which hydrogen atom abstraction from the amine by triplet ketone is the primary chemical reaction. The results are not in accord with the participation of singlet oxygen. Quantum yield measurements of oxygen uptake, amine disappearance, and product formation are consistent with the proposed mechanism.
Chemischer Informationsdienst, 1972