Crystal structure of (E)-4-methyl-N-{2-[2-(4-nitrobenzylidene)hydrazin-1-yl]-2-oxoethyl}benzenesulfonamideN,N-dimethylformamide monosolvate

The molecule of the title Schiff base compound, C16H16N4O5S·C3H7NO, displays atransconformation with respect to the C=N double bond. The C—N and N—N bonds are relatively short compared to their normal bond lengths, indicating some degree of delocalization in the molecule. The molecule is bent at the S atom, with an S—N—C—C torsion angle of 164.48 (11)°. The dihedral angle between the two aromatic rings is 84.594 (7)°. Intermolecular N—H...O and C —H...O hydrogen bonds connect centrosymmetrically related molecules into dimers forming rings ofR33(11) andR22(10) graph-set motif stacked along theaaxis into a columnar arrangement. The molecular columns are further linked into a three-dimensional network by C—H...π interactions.

Gold Wirebond on Discolored Bond Pads

An integrated circuit wafer lot having some wafers with discolored bond pads and other wafers with normal bond pads was identified, and wafers with discolored pads were scrapped. The reason for scrap is the expectation of poor bondability or unreliable wirebonds on discolored pads. The cause of discoloration was unknown. We took the opportunity to run a bonding experiment and analysis as a student project, comparing a good wafer with one having the discolored bond pads. Unprobed die from each wafer were wirebonded for mechanical integrity analysis of the bonds. Bonding recipe designed experiments included different ultrasonic generator (USG) current settings within the bonding process window, two bonding forces, and two temperatures, all thermosonic binding 25um gold (Au) wire on AlCu pad metal of 0.7um thickness. 2% non-stick-on pads (NSOP) was found at a higher ultrasonic power settings on the discolored pads, indicating that the discolored pads can indeed be problematic in wirebonding. Analysis of wire pull test and bond shear test results indicate slightly less performance of bonds on the discolored pads. Chemical and physical analysis of the discolored pads reveals the nature of the unknown cause and leads to a hypothesis about what went wrong during the wafer processing.

Experiment Study on Interfacial Normal Bond Strength of Concrete Filled Steel Tube

To study the debonding of concrete filled steel tube (CFST), pulling and bending methods were used to test the normal bond strength. Based on the test result, debonding due to temperature change and shrinkage of core concrete in CFST was analyzed. The test and analysis result shows that the bending method is a better test method; the concrete strength has little influence on bond strength while the surface condition of steel has much influence on it. The bond strength of steel which is rust is greater than that of the steel with smooth surface. According to the analysis on the bending test result, the normal bond strength of 0.86MPa was got and the debonding of CFST arch was analyzed, the analysis result shows that debonding will easily happen under the action of temperature change and shrinkage of core concrete. The test methods and results can provide a reference for engineering applications.

Lead hydrogen citrate monohydrate, Pb(C6H6O7)·H2O, formation during specimen cleaning: a cautionary mineralogical tale

Crystal-structure analysis was used to identify crystals of Pb(C6H6O7)·H2O on a specimen of hematite pseudomorphous after magnetite from the Payύn Matrύ volcanic field, Mendoza Province, Argentina. The compound is triclinic, P, a = 6.3434(2), b = 6.4566(2), c = 12.0640(9) Å, α = 99.233(7), β = 102.810(7), γ = 101.562(7)° and Z=2. The crystal structure, refined to R1 = 0.0169 for 2021 reflections [Fo>4σ(F)], consists of a zig-zag chain of 9-coordinated Pb2+ atoms along b. Chains are linked together by citrate molecules to form thick irregular layers in the ab plane. The layers are linked together only by H bonds. The citrate molecule exhibits normal bond lengths and angles. The Pb2+ atom exhibits markedly lopsided coordination due to the 6s2 lone-electron-pair effect. The lone electron pairs on alternating sets of adjacent Pb2+ atoms in the chain point towards one another.The formation of the Pb(C6H6O7)·H2O crystals was the result of specimen cleaning in citric acid. The cleaning solution was apparently contaminated through the dissolution of minor associated Pb-bearing species by the citric acid. It is important to be aware of the possibility that micro-crystals may be inadvertently grown on mineral specimens during chemical cleaning, to carefully and critically inspect paragenetic relationships especially when studying mineral specimens that may have been cleaned in chemical agents, and to be particularly aware of health risks when treating Pb-bearing minerals in aqueous citric acid solutions.

Influences of Microscopic Factors on Macroscopic Strength and Stiffness of Inter-Layered Rocks — Revealed by a Bonded Particle Model

Since a conventional petrographic analysis does not allow a systematic and detailed study on how the microscopic factors affect the macroscopic behavior of inter-layered rocks, this research adopted a numerical model, the bonded particle model, to explore the micro-mechanisms associated with the strength and stiffness of inter-layered rocks. The model was first calibrated by comparing the simulations to the actual behavior until they tally with each other. Following, the microscopic factors, including the bond strength, the bond stiffness, type of bonds and friction of particles and type of bond stiffness, are varied to study their influences. As expected, the bond strength and the bond stiffness are found to have a direct and significant influence on the macroscopic uniaxial compressive strength and stiffness, respectively. Furthermore, close observations on the breaking of bonds during the loading process reveal interesting phenomena, including the transition of shear/normal bond breaking, the type of internal fracture and the factors controlling internal failure, etc. These phenomena enlighten the interpretations about the micromechanisms accounting for the macroscopic strength and stiffness of inter-layered rocks.