Logic of proofs with substitution

The substitution operation in logic of proofs is axiomatized. For the system constructed, symbolic semantics is introduced and a completeness theorem is proved.     

“调配问题”及经济数学的一组公式

本文是介绍解决资源开发，运输决策等社会现象的问题中归纳出来的“调配问题”及经济数学的一组公式（ｎ）∑（ｉ＝１）ＳｉＴａｉ≥（ｎ）∑（ｉ＝１）ＳｉＴｎ－ｉ＋１；（ｎ）∑（ｉ＝１）ＳｉＴｉ≥（ｎ）∑（ｉ＝１）ＳＩＴａｉ。     

Why fluorinate fullerenes?

This review explores the reasons for fluorinating fullerenes, describes mechanistic deductions from studies carried out to date, explores future directions, and evaluates applications to large-scale preparative chemistry. Some previous structural characterisations are updated in the light of more recent data and interpretations.     

Reaction of secondary amines with 2-(imidazol-1-yl)-perfluoro-5,5-dimethyl-4-ethylidene-2-thiazoline

Reactions of 2-(imidazol-1-yl)-perfluoro-5,5-dimethyl-4-ethylidene-2-thiazoline with a series of secondary amines in THF resulted in the replacement of the imidazole moiety by the amine moiety. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 831–834, April, 1997.     

Spectroscopic parameters of CHFCl2, CHClF2, C2F6, and C3F8 molecules

We investigate the IR spectra of solutions of R-21,-22,-116, and R-218 in liquid argon at 90K. The frequencies, half-widths, and absolute integral intensities of all of the absorption bands recorded are obtained and interpreted. Scientific-Research Institute of Physics, 1, Ul'yanovskaya Str., Petrodvorets, St. Petersburg, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 3, pp. 297–301, May–June, 1997.     

Preparation of α-substituted γ-alkoxyallylstannanes from β-tributylstannyl acrolein acetals: scope of the method and primary rationalization of the obtained results

α-Substituted γ-alkoxyallylstannanes were obtained from β-tributylstannyl acrolein acetals when reacted with lower order magnesium cyanocuprates in the presence of boron trifluoride at low temperature. In the case of n-alkylcyanocuprates an anti S_N2′ substitution on a cisoid conformation appears to be the main reaction pathway. However, subtle competitions with other mechanisms may occur depending on the experimental conditions, on the reagents or on the substrates. These drawbacks constitute limitations for the use of the method especially when enantioenriched α-substituted γ-alkoxyallylstannanes are desired.     

The effect of element substitution on high-temperature thermoelectric properties of Ca3Co2O6 compounds

Polycrystalline Ca₃Co_1.8M_0.2O₆ (M=Mn, Fe, Co, Ni, Cu) and Ca_2.7Na_0.3Co₂O₆ were synthesized by solid-state reaction to evaluate the effect of substitution on the thermoelectric properties of Ca₃Co₂O₆. Substitution by Mn, Cu and Na appears to increase carrier density, given that electrical resistivity (ρ) and the Seebeck coefficient (S) were simultaneously reduced. Conversely, Fe substitution seems to reduce carrier density, resulting in a simultaneous increase in S and ρ. Cu and Na substitution resulted in a significant decrease in ρ due to enhancement of grain size and grain boundary connectivity, which could have a strong impact on ρ. Not only the intrinsic substitution effect on the electronic state but also this modification of the microstructure plays an important role in improvement of the thermoelectric power factor, particularly in the case of the Na-substituted sample.     

Lead structures for applications in photodynamic therapy. Part 1: Synthesis and variation of m-THPC (Temoporfin) related amphiphilic A2BC-type porphyrins

Photodynamic therapy (PDT) is a developing modality for the treatment of certain tumorous and other diseases. Considerable progress has been made in recent years in the search for new photosensitizers, in particular elucidating the role of localization of the photosensitizer. Known successful photosensitizers of the tetrapyrrole type are amphiphilic molecules, preferably localizing in cellular membrane structures. Thus, the quest for new photosensitizers requires the synthesis of unsymmetrically substituted (amphiphilic) tetrapyrroles. In this article, we describe strategies for the de novo synthesis of amphiphilic tetrapyrroles using a 3-hydroxyphenyl substituted tetrapyrrolic system (Temoporfin) as the lead structure. From an applied science-oriented approach, such a set of amphiphilic porphyrins is best synthesized by combining well-developed condensation methods with subsequent functionalization via organolithium compounds or transition metal catalyzed coupling protocols. Starting from simple A₂- or AB-porphyrins, the synthesis of A₂B-, A₃-, A₃B-, and A₂BC-porphyrins with a mixed hydrophilic/hydrophobic substitution pattern is described. Because of the versatility of this approach to unsymmetrically substituted porphyrins it is also applicable to other areas where porphyryns with a tailor-made substitution patterns are needed, for example, catalysts or molecular electronic devices based on tetrapyrroles.