Reliability of QFP (quad flat package) solder joints after thermal shock was investigated for PCB’s and connecting leads plated with several different alloy coatings before soldering. Sn–8 wt%Zn–3 wt%Bi (hereafter, Sn–8Zn–3Bi) was selected as a solder, and FR-4 PCB’s finished with Cu/Sn, Cu/OSP and Cu/Ni/Au were used as substrates. The leads of the QFP were Cu plated with Sn–10 wt%Pb, or Sn, or...

Fast-scan cyclic voltammetry (CV) and scanning electrochemical microscopy (SECM) were used to investigate the reduction of Sn(IV) as the hexabromo complex ion in a 2 M HBr-4 M NaBr medium. CV at scan rates to 100 V/s and SECM indicated the reaction pathway involves ligand-coupled electron transfer via an ECEC-DISP process: (1) one-electron reduction of Sn(IV)Br6(2-) to Sn(III)Br6(3-); (2) bromi...

We report on our early photometric and spectroscopic observations of the extremely luminous Type II supernova (SN) 2008es. With an observed peak optical magnitude of mV = 17.6 mag and at a redshift z = 0.213, SN 2008es had a peak absolute magnitude of MV = −22.5 mag, making it the second most luminous SN ever observed. The photometric evolution of SN 2008es exhibits a fast decline rate (∼0.042 ...

euphorbia macrostegia or persian wood spurge is one of the seventeen endemic plants of this genus in iran. three triterpenoids: 24-methylenecycloartan-3β-ol (1), butyrospermol (2) and cycloartenol (3) and three diglycerides: 1,2-di-o-α-linolenoyl-sn-glycerol (4), 1-o-linoleoyl-3-o-palmitoyl-sn-glycerol (5) and 1-o-α-linolenoyl-2-o-palmitoyl-sn-glycerol (6) were isolated from a hexane layer of m...

Define a sequence (sn) of two-variable words in variables x, y as follows: s0(x, y) = x, sn+1(x, y) = [sn(x, y)−y, sn(x, y)] for n > 0. It is shown that a finite group G is soluble if and only if sn is a law of G for all but finitely many values of n.

This paper shows that sn-metrizable spaces can not be characterized as sequence-covering, compact, σ-images of metric spaces or sn-open, π, σ-images of metric spaces. Also, a space with a locally countable sn-network need not to be an sn-metrizable space. These results correct some errors on sn-metrizable spaces. AMS Mathematics Subject Classification (2000): 54C05, 54E35, 54E40

Polynomials are defined recursively in various ways associated with reciprocation; e.g., Sn+1(x)/Tn+1(x) = Sn(x)/Tn(x) ± Tn(x)/Sn(x). Under certain conditions, the zeros of Sn interlace those of Tn. Identities for Sn, Tn, and related polynomials are derived, as well as recurrence relations and infinite sums involving roots of polynomials.

The purpose of this paper is to give an explicit description of the irreducible decomposition of the multigraded Sn-module of coinvariants of Sn×Sn. Many of the results presented can be extended to S n , and analogous questions for other finite reflection group.

Nano-Sn/C composites are ideal anode materials for high energy and power density Li-ion batteries. However, because of the low melting point of Sn and the tendency of grain growth, especially during high temperature carbonization, it has been a significant challenge to create well-dispersed ultrasmall Sn nanoparticles within a carbon matrix. In this paper, we demonstrate an aerosol spray pyroly...

We described the use of a new chemical substance Sodium nucleinate (SN) as an immunomodulatory substance exhibiting antiinflammatory properties. Sodium nucleinate (SN) registrated in Russian Federation as Tamerit, is 2-amino-1,2,3,4-tetrahydrophthalazine-1,4-dione sodium salt dihydrate, derivative of well known chemical substance luminol. To comprehend the mechanisms of SN immunomodulatory acti...