Theory of error for target factor analysis with applications to mass spectrometry and nuclear magnetic resonance spectrometry

Based on the theory of error for abstract factor analysis described earlier, a theory of error for target factor analysis is developed. The theory shows how the error in the data matrix mixes with the error in the target test vector. The apparent error in a target test is found to be a vector sum of the real error in the target vector and the real error in the predicted vector. The theory predicts the magnitudes of these errors without requiring any a priori knowledge of the error in the data matrix or the target vector. A reliability function and a spoil function are developed for the purpose of assessing the validity and the worthi-ness of a target vector. Examples from model data, mass spectrometry and nuclear magnetic -resonance spectrometry are presented.     

Crystal structures and properties of catena-μ-nitrato (7-amino-5-aza-4-methyl-3-hepten-2-onato) copper(II) and μ3-hydrox-otris(μ-8-amino-5-aza-4-methyl-3-octen-2-onato) tricopper(II) dinitrate

The products of monocondensation of penta-2,4,-dione with 1,2-diaminoethane, HAE, and with 1,3-diaminopropane, HAT, react with copper nitrate hemipentahydrate to give catena--nitrato (7-amino-5-aza-4-methyl-3-hepten-2-onato) copper(II), [Cu(AE)NO₃]_n and a mixture of ₃-hydroxo-tris (-8-amino-5-aza-4-methyl-3-octen-2-onato) tricopper(II) dinitrate [Cu₃(AT)₃OH]-(NO₃)₂ and [Cu(AT)NO₃]_x, respectively. The structure of [Cu(AE)NO₃]_n has been determined from 1601 diffractometer data and refined by least squares methods toR=0.0306. The compound crystallizes in the monoclinic space groupP2₁/a witha=16.856(3)Å,b=8.109(4)Å,c=7.518(3)Å,=90.15(2)°,D _c =1.725 g cm^–3,D _o=1.72 g cm^–3 andZ=4. Copper atoms in [Cu(AE)NO₃]_n are in a 4+1+1^* environment and are linked by the pseudobidentate and bridging nitrato group into infinite chains. The structure of [Cu₃(AT)₃OH](NO₃)₂ has been determined from 3178 diffractometer data and refined toR=0.0544. The compound crystallizes in the triclinic space groupP¯1 witha=11.918(2)Å,b=14.478(2)Å,c=11.501(3)Å,=98.04(2)°,=117.72(2)°, =99.80(1)°,D _c =1.580 g cm^–3,D _o=1.59 g cm^–3 andZ=2. The compound is associated in hexanuclear clusters due to hydrogen bonding interactions. Coordination about Cu is best described as square pyramidal. Magnetic susceptibility data indicate a weak antiferromagnetic exchange within the trinuclear core withJ=–14 cm^–1.     

Effect of deuterium on the kinetics of 1,5-hydrogen shifts: 5-dideuteriomethylene-2,4,6,7,9-pentamethyl-11,11a- dihydro-12H-naphthacene

To obtain a more reliable temperature dependence of the kinetic deuterium isotope effect in a 1,5-hydrogen shift, the title compound has been designed to repress compromising side reactions, arguably arising from second-order ene-ene unions. The values of kH/kD, 4.58-5.15, in the range 185.8-153.8 degrees C, on extrapolation by the derived Arrhenius equation, lead to 8-14 at 25 degrees C. Another goal is the evaluation of the effect on rates of the free rotation available to the phenyl groups in 2,4-diphenyl-1,3(Z)-pentadiene compared to the constraint to coplanarity of the phenyl groups in the title compound. The effect is insignificant. Incidental to the presence of the sterically effective methyl groups in the title compound, participation of the hydrogen atoms of an aromatic methyl group as part of the 1,3(Z)-pentadienyl system has been uncovered in 6,8-dimethyl-1-methylene-1,2,3,4-tetrahydronaphthalene. The rate of the rearrangement is too slow to compromise the kinetics of the hydrogen shifts in the title compound. A reassessment of the conventional procedure for estimating uncertainties in Arrhenius parameters based on a small number of rate constants has led to the proposal of an alternative procedure based on the statistically more significant uncertainties associated with the individual rate constants.     

A neutron diffraction study of the d and d lithium garnets Li3Nd3W2O12 and Li5La3Sb2O12

The garnets Li₃Nd₃W₂O₁₂ and Li₅La₃Sb₂O₁₂ have been prepared by heating the component oxides and hydroxides in air at temperatures up to 950 °C. Neutron powder diffraction has been used to examine the lithium distribution in these phases. Both compounds crystallise in the space group with lattice parameters a=12.46869(9) Å (Li₃Nd₃W₂O₁₂) and a=12.8518(3) Å (Li₅La₃Sb₂O₁₂). Li₃Nd₃W₂O₁₂ contains lithium on a filled, tetrahedrally coordinated 24d site that is occupied in the conventional garnet structure. Li₅La₃Sb₂O₁₂ contains partial occupation of lithium over two crystallographic sites. The conventional tetrahedrally coordinated 24d site is 79.3(8)% occupied. The remaining lithium is found in oxide octahedra which are linked via a shared face to the tetrahedron. This lithium shows positional disorder and is split over two positions within the octahedron and occupies 43.6(4)% of the octahedra. Comparison of these compounds with related d⁰ and d¹⁰ phases shows that replacement of a d⁰ cation with d¹⁰ cation of the same charge leads to an increase in the lattice parameter due to polarisation effects.     

The effect of discharge power density on polyethylene terephthalate film surface modification by dielectric barrier discharge in atmospheric air

Polyethylene terephthalate (PET) films are modified using non-equilibrium plasma generated by DBD in atmospheric air, and the effects of discharge power density on the surface modification are studied. It is found that increasing discharge power density can induce more effective treatment of PET films, because this leads to a faster decrease in water contact angle and a faster increase in surface energy due to more creation of polar groups and more obvious etching occurring on the PET surface. So the treatment time needed to achieve the same level of surface treatment can be reduced by increasing the discharge power density.