The assessment of compliance with legal limits. Part 2. How to consider both type I and type II errors when working in the concentration domain

Considering the uncertainty of measurement when assessing compliance with reference values given in compositional specifications and statutory limits is still a controversial matter. In theory, assessing compliance requires considering both type I (false positive) and type II (false negative) errors. The more the concentration of the analyte in the sample under investigation is close to the allowed concentration limit, the more critical it is to consider both types of errors. This paper describes how this could be done. The matter is discussed in the light of the most recent literature information.     

On the calculation of arbitrary multielectron molecular integrals over Slater‐type orbitals using recurrence relations for overlap integrals. III. Auxiliary functions \documentclass{article}\pagestyle{empty}\begin{document}$Q_{nn'}^{q}$\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$G_{-nn'}^{q}$\end{document}

The auxiliary functions $Q_{nn'}^{q}(p,pt)$ and $G_{-nn'}^{q}(p_{a},p,pt)$ which are used in our previous paper [Guseinov, I. I.; Mamedov, B. A. Int J Quantum Chem 2001, 81, 117] for the computation of multicenter electron‐repulsion integrals over Slater‐type orbitals (STOs) are discussed in detail, and the method is given for their numerical computation. The present method is suitable for all values of the parameters p_a, p, and pt. Three‐ and four‐center electron‐repulsion integrals are calculated for extremely large quantum numbers using relations for auxiliary functions obtained in this paper. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem, 2001     

Crystal structure of synthetic Cu3SeO4(OH)4

Summary The crystal structure of synthetic Cu₃SeO₄(OH)₄ was determined by single crystal X-ray methods:a=8.382 (2) Å,b=6.087 (1) Å,c=12.285 (2) Å,V=626.8 ų,Z=4, space group Pnma,R=0.026,R _w =0.021 for 1255 independent reflections (sin / 0.8 Å^–1). The crystal structure is isotypic to that of the mineral antlerite, Cu₃SO₄(OH)₄. The copper atoms are Jahn-Teller distorted with Cu^[4+2]O₆ polyhedra forming triple chains along [010]. These chains are linked via SeO₄ tetrahedra and weak hydrogen bonds to a framework structure.

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Die Kristallstruktur von synthetischem Cu₃SeO₄(OH)₄

Zusammenfassung Die Kristallstruktur von synthetischem Cu₃SeO₄(OH)₄ wurde mittels Einkristall-Röntgenmethoden ermittelt:a=8.382 (2) Å,b=6.087 (1) Å,c=12.285 (2) Å,V=626.8 ų,Z=4, Raumgruppe Pnma,R=0.026,R _w =0.021 für 1255 unabhängige Reflexe (sin / 0.8 Å^–1). Die Kristallstruktur ist isotyp mit der des Minerals Antlerit, Cu₃SO₄(OH)₄. Die Kupferatome sind Jahn-Teller-verzerrt, die Cu^[4+2]O₆ Polyeder bilden Dreierketten entlang [010]. Diese Ketten sind über SeO₄-Tetraeder und schwache Wasserstoffbrücken zu einer Gerüststruktur verbunden.

     

Analysis of polynuclear aromatic hydrocarbons by glass capillary gas chromatography using simultaneous flame ionization and electron capture detection

The possibility of simultaneous application of an electron capture (ECD) and a flame ionization detector (FID) connected to a glass capillary column for analyzing polynuclear aromatic hydrocarbons (PNA) has been investigated. The ECD/FID ratio is determined for 46 PNA compounds. The ratios vary from 0.02 to 117 with relative standard deviations better than 20 percent determined from 10 replicate analyses. The results suggest that the method may be used for obtaining additional evidence in identifying PNA in environmental samples. Impurities and transformation products in the standard were identified by computerized glass capillary gas chromatography/mass spectrometry. Quinones and diones are responsible for the high EC-response determined in some trace components in the standard. An application of the method is shown for PNA from particulates in urban atmospheres.     

Über Perrhenate. 3 Zum Aufbau des Mesoperrhenates Na3[ReO5]

About Perrhenates. 3 On the Structure of the Mesoperrhenate Na₃[ReO₅] By tempering powder samples (prepared from mixtures of binary oxides: Na₂O₂/ReO₂ and Na₂O/ReO₃ respectively, Na : Re = 3 : 1, Ar and O₂ atmosphere respectively, 400–450°C, corundum boat) in a closed Ag cylinder (500–550°C, 10 d) yellow single crystals of Na₃ReO₅, sensitive to moisture, were grown. The compound crystallizes trigonal, space group P3₁, P3₂ respectively, with a = 5.544(1), c = 13.580(7) Å, Z = 3, d_rö. = 4.62 g/cm³. The crystal structure [4-circle diffractometer data, 1091 I₀(hkl), AgKα, R = 6.14, R_w = 6.08%] is characterized by “isolated” bipyramids ReO₅. Na⁺ ions are occupying all the tetrahedral (Na2, Na3) and octahedral (Na1) holes of the pseudocubic face centred (c/a = 2.441) Re part of the lattice; resulting in a Na₃Re kation framework corresponding to the Li₃Bi type of structure. Effective Coordination Numbers (ECoN), the Madelung Part of Lattice energy (MAPLE) and the charge distribution (CHARDI) are computed and discussed.     

Three New Serratane Triterpenoids from Phlegmariurus squarrosus

Three new serratane triterpenoids, (3α,14α,15α,21α)‐3,14,15,21,29‐pentahydroxyserratan‐24‐oic acid ( 1 ), (3α,21β)‐serrat‐14‐ene‐3,21,24,30‐tetraol ( 2 ), and (3α,21α)‐serrat‐14‐ene‐3,21,24,29‐tetraol ( 3 ), were isolated from Phlegmariurus squarrosus, together with eight known compounds. Their chemical structures were elucidated on the basis of in‐depth spectroscopic analyses.     

Das erste Diniobat mit ‚isolierten’︁ Anionen: KLi4[NbO5]=K2Li8[Nb2O10]

The First Diniobate with ‘Isolated’ Anions: KLi₄[NbO₅]=K₂Li₈[Nb₂O₁₀] [1] . By heating of well ground mixtures of the binary oxides [K₂O, Li₂O, Nb₂O₅, K:Li:Nb=1.1:4.4:1, Pt-tube, 1100°C, 3d] colourless, triclinic single crystals of KLi₄NbO₅ have been prepared for the first time: space group P1 (Nr. 2) with a=816.9(2) pm, b=592.2(2) pm, c=589.7(2) pm, α=121.00(2)º, β=91.78(2)°, γ=99.23(2)°, Z=2. The crystal structure was solved by four-cycle diffractometer data [Mo-Kα , 1386 from 1386 I_o(hkl), R=3.4%, R_w=2.6%], parameters see text. Characteristic for this structure are “isolated” groups of [Nb₂O₁₀] and the tetrahedral coordination of Li(1), Li(2), and Li(3). Li(4) has a tetragonal-pyramidal coordination. The structural relations are deduced by Schlegel Diagrams. The Madelung Part of Lattice Energy, MAPLE, the Effective Coordination Numbers, ECoN and the charge distribution have been calculated and discussed.     

Evaluation of two‐center,three‐ and four‐electron integrals over Slater‐type orbitals in elliptical coordinates

An algorithm for evaluation of two‐center, three‐electron integrals with the correlation factors of the type rr and rrr as well as four‐electron integrals with the correlation factors rrr and rrr in the Slater basis is presented. This problem has been solved here in elliptical coordinates, using the generalized and modified form of the Neumann expansion of the interelectronic distance function r for k ≥ ?1. Some numerical results are also included. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004     

碱金属改性Y分子筛的甲苯氧化甲基化反应性能及基酸碱性质

碱金属改性Ｙ分子筛的甲苯氧化甲基化反应性能及其酸碱性质＊周灵萍李伟苏明李赫口亘陶克毅＊＊（南开大学化学系，天津３０００７１）关键词Ｙ型分子筛，甲苯，甲烷，氧化甲基化，苯乙烯，乙苯，酸性，碱性分类号Ｏ６４３／ＴＱ４２苯乙烯和乙苯是重要的化工原料．以往合...