案例1:HCD1328(118)TSD线路板短路漏电的原因

一、样品描述 所送样品为型号为HCD1328(118)TSD的线路板,该批板有不同程度的短路漏电现象,而与之配套的显示板和芯片内依线显示正常,今委托单位要求分析该板短路漏电的原因。     

Synthesis and dispersion of Ni(OH)2 platelet-like nanoparticles in water

Synthesis of nanometric platelet-like Ni(OH)2 particles is described. The role of several experimental parameters on the particle size is investigated. A colloidal dispersion of particles is produced by adsorbing ionizable organic ligands (trisodium citrate) on the particle surface. The stability of this colloidal dispersion and the particle charge density are determined for different citrate ions concentrations.     

Additional of functional vinylzinc reagents to nitrones: synthesis of (E)-N-allylhydroxylamines and their rearrangement into (E)-O-allylhydroxylamines

The vinylzinc reagents derived from hydrozirconation of alkynes and transmetallation add readily to nitrones to yield pure (E)-N-allylhydroxylamines; some of these rearrange into O-allylhydroxylamines.     

Monitoring of the metal displacement from the recombinant mouse liver metallothionein Zn(7)-complex by capillary zone electrophoresis with electrospray MS detection

A solution of a Zn-complex of recombinant mouse MT-1 isoform (Zn(7)-MT-1) was prepared and titrated with Cd(2+) ions. A method based on the coupling of capillary zone electrophoresis (CZE) with electrospray MS detection was developed for the analysis of the stoichiometry of the species formed during the titration. The method offered the possibility of the on-line removal of up to 100 mM Tris or phosphate buffer solutions that would otherwise suppress the electrospray signal. By allowing the determination of the metal stoichiometry of the complex species present in solution the method was shown to be complementary to circular dichroism and UV-VIS spectrophotometry conventionally used for similar studies. The titration of the Zn(7)-MT complex with Cd(II) showed the sequential displacement of the Zn by Cd. The unusually high stability of the Cd(6)Zn(1)-MT species was observed which suggests a structural role of the remaining Zn(II) ion.     

Ph2SO/Tf2O: a powerful promotor system in chemoselective glycosylations using thioglycosides

Diphenylsulfoxide in combination with triflic anhydride provides a very potent thiophilic glycosylation promotor system, capable of activating disarmed thioglycosides. The usefulness of this novel thiophilic activator is illustrated in a successful chemoselective glycosylation sequence in which the donor thioglycoside in the first condensation step may be either armed or disarmed. [reaction: see text]     

Synthesis and structures of cis- and trans-bis(alkyneselenolato)platinum(II) complexes

The reaction of 2 equiv of LiSeCC-n-C(5)H(11) (1) with cis-PtCl(2)(Ph(3)P)(2) (2) gives a mixture of the cis and trans isomers of Pt(Ph(3)P)(2)(SeCC-n-C(5)H(11))(2) (3), which slowly isomerizes in CH(2)Cl(2) to the preferred trans form trans-3. The closely related cis-[Pt(dppf)(2)(SeCC-n-C(5)H(11))(2)] (4) (dppf = bis(diphenylphosphino)ferrocene) was prepared by a similar metathetical reaction using the platinum chloride complex of the chelating dppf to impose the cis geometry. The structures of the cis and trans complexes have been investigated in solution by heteronuclear NMR ((31)P, (77)Se, and (195)Pt) and, in the cases of trans-3 and 4, characterized in the solid state by single-crystal X-ray diffraction. Changing the coordination geometry from cis to trans induces significant changes in the structural and spectroscopic parameters, which do not comply with the previously anticipated donor-acceptor properties of selenolate ligands.     

From allylic alcohols to aldols by using iron carbonyls as catalysts: computational study on a novel tandem isomerization-aldolization reaction

The tandem isomerization-aldolization reaction between allyl alcohol and formaldehyde mediated by [Fe(CO)3] was studied with the density functional B3LYP method. Starting from the key [(enol)Fe(CO)3] complex, several reaction paths for the reaction with formaldehyde were explored. The results show that the most favorable reaction path involves first an enol/allyl alcohol ligand-exchange process followed by direct condensation of formaldehyde with the free enol. During this process, formation of the new C-C bond takes place simultaneously with a proton transfer between the enol and the aldehyde. Therefore, the role of [Fe(CO)3] is to catalyze the allyl alcohol to enol isomerization affording the free enol, which adds to the aldehyde in a carbonyl-ene type reaction. Similar results were obtained for the reaction between allyl alcohol and acetaldehyde.