Temperature and Oxygen Partial Pressure Dependences of the Surface Tension of Liquid Sn–Ag and Sn–Cu Lead-free Solder Alloys

Temperature dependence of the surface tension of liquid Sn–Ag and Sn–Cu base lead-free solder alloys and oxygen partial pressure dependence of liquid Sn–Ag alloy were evaluated using the experimental data obtained, respectively, by the constrained drop method and the sessile drop method in the previous studies [1, 2]. The temperature dependences of the surface tension have maximum positive values when the mol fraction of Ag and Cu is about 0.7, while those for pure liquid Sn, Ag, and Cu have negative values. The calculated values based on Butler’s equations were found to be in reasonable agreement with those of the experimental data. The oxygen partial pressure dependences of the surface tension of liquid Sn–Ag alloys at 1253 K have a minimum value when the mol fraction of Ag is about 0.9 and the oxygen partial pressure is less than about 10⁻¹³ atm. From this, it is considered that the oxygen adsorption increased by adding Ag to Sn when the mol fraction of Ag is less than 0.9.     

On the electronic states of macrocycles of the extended porphyrin family and their coordination compounds

The electronic absorption spectra of Ni, Zn and Mg hemiporphyrazine derivatives are presented and discussed together with theoretical results obtained by INDO/S computations. The absorption spectra of all the metal derivatives show marked red shifts of the lowest energy absorption bands with respect to those of the metal free hemiporphyrazine. The possible explanation that in metal derivatives low lying excited states with a fully conjugated π electron system are present is supported by theoretical computations.     

Triplet state formation and type II decomposition in the photochemistry of pentanone-2

The concentration dependences of the quantum yields of Norrish type II decomposition from the singlet and triplet states and of the triplet yiel were determined in pentanone-2 photolysis in iso-octane. The results were interpreted by postulating dissociative intersystem crossing of a singlet exciplex as an additional route for the population of the molecular triplet state.

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II -2 . , .

     

UV-VIS spectroscopic study of interaction and transformation of allyl alcohol on zeolites HZSM-5

Formation of alkenylcarbenium ions has been proved during transformation of allyl alcohol on zeolite HZSM-5.

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HZSM-5.

     

Covalent immobilization of heparin on a collagen film

Four procedures for the covalent immobilization of heparin (Hp) on a collagen film (CF) have been investigated. In three of them (methods (I–A, B, C), the CF was first treated with epichlorohydrin and ammonia and the Hp was added with the aid of CMBC (method I–A), by reductive amination in the presence of NaCH CN (method I–B), and with the aid of CMEC after succinylation (method I–C). In the fourth procedure (method II), the CF was activated by treatment with alkali and the Hp was added with the aid of CMEC. It was shown that the maximum amount of Hp was immobilized by method II.M. V. Lomonosov Moscow State University. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 700–704, September–October, 1987.     

Structure of aerugine from Pseudomonas aeruginosa

A new optically active phenolic alkaloid with the composition C₁₀H₁₁NO₂S, mp 85–88°C, []_D +28° (c 1.0; chloroform) (I) has been isolated from the microorganismPseudomonas aeruginosa (strain 590) and has been called aerugine. The action of diazomethane gave an O-methyl derivative (II). On the basis of the formation of ortho-cresol by the hydrogenolytic desulfuration reaction, a study of the IR, mass, and PMR spectra and (I) and its acetyl derivative (III), and also the¹³C NMR spectrum of (I), the structure of 4-hydroxymethyl-2-(o-hydroxyphenyl)-2-thiazoline has been established for aerugine. The spectral characteristics of the compounds mentioned are given.Institute of the Chemistry of Plant Substances of the Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 553–558, July–August, 1987.     

Reactions of C4?C6 alkanes on platinum and platium-gold films

Results are reported on the reactions of n-butane, n-pentane and n-hexane on Pt and Pt/Au alloy films. The results are compared with those obtained for Pt–Au alloys on a SiO₂ carrier. It is concluded that alloying can change the selectivity of the catalyst. No indication has been found for the possible role of oxygen in the high selectivity of Pt in non-destructive reactions.

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-, - - Pt . , Pt–Au SiO₂. , . - Pt .

     

Interaction of phosphomolybdovanadium heteropolyacids with hydrazine hydrate studied by a calorimetric method

The heats of interaction of VO ₂ ⁺ and of heteropolyacids H_3+nPMo_12−nV_nO₄₀ (n=1,2,3,6) with N₂H₄ have been measured.

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Измерены теплоты взаимодействия VO ₂ ⁺ и гетерополикислот H_3+nPMo_12−nV_nO₄₀ (n=1,2,3,6) с N₂H₄.

     

A chemical study ofPlectranthus glaucocalyx Maxim.

Summary A previously unknown crystalline substance C₂₀H₂₈O₄, calledplectrin, has been isolated from the leaves ofPlectranthus glaucocalyx Maxim., family Labiatae.Khimiya Prirodnykh Soedinenii, Vol. 1, No. 6, pp. 427–428, 1965     

A study of the reactions of the chemical modification of chymotrypsin. I

Summary The reaction of chymotrypsin with a number of modified analogs of the specific inhibitor of chymotrypsin L-1-tosylamido-2-phenylethyl chloromethyl ketone has been studied; the compounds investigated were D-1-tosylamido-2-phenethyl chloromethyl ketone, phenethyl chloromethyl ketone (PECK), and benzylethyl chloromethyl ketone (BCMK).It has been shown that D-TAPK does not possess inhibiting activity. The inhibiting capacity of PECK is considerably reduced. A simultaneous decrease in the length of the carbon chain and the elimination of the tosylamino group (BCMK) practically destroys the inhibiting action of the reagent.Khimiya Prirodnykh Soedinenii, Vol. 4, No. 2, pp. 116–120, 1968