Adhesion of electrolessly deposited Ni(P) layers on alumina ceramic II. Interface characterization

The interface microstructure and interface chem. of electrolessly deposited Ni(P) on alumina ceramics is studied to obtain insight into the influence of mol. interactions upon the adhesion. Detailed static secondary-ion-mass spectrometry, XPS, Auger electron spectroscopy, and transmission electron microscopy (TEM) analyses have been carried out with samples with various roughness, of which the mech. analyses are described in a companion article. TEM cross-section micrographs showed a close contact between the two phases on a nanometer scale for all sample types. In addn., a 1-2-nm-thick interfacial layer was obsd. This layer consists of nucleation material and compds. from the metalization soln. Fracture surface analyses showed that fracture takes place through this layer, which is therefore considered to be the weak boundary layer in this system. The presence of this weak boundary layer explains the importance of substrate surface roughness and mech. interlocking for the fracture energy. [on SciFinder (R)

Review Section : Nature/Nurture Revisited I

Biologically oriented approaches to the study of human conflict have thus far been limited largely to the study of aggression. A sample of the literature on this topic is reviewed, drawing upon four major approaches: comparative psychology, ethology (including some popularized accounts), evolutionary-based theories, and several areas of human physiology. More sophisticated relationships between so-called "innate" and "acquired" determinants of behavior are discussed, along with the proper relevance of animal behavior studies for human behavior. Unless contained in a comprehensive theory which includes social and psychological variables, biolog ically oriented theories (although often valid within their domain) offer at best severely limited and at worst highly misleading explanations of complex social conflicts. The review concludes with a list of several positive contributions of these biological approaches and suggests that social scientists must become more knowledgeable about them.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68270/2/10.1177_002200277401800206.pd

Discovery of widespread transcription initiation at microsatellites predictable by sequence-based deep neural network

Using the Cap Analysis of Gene Expression (CAGE) technology, the FANTOM5 consortium provided one of the most comprehensive maps of transcription start sites (TSSs) in several species. Strikingly, ~72% of them could not be assigned to a specific gene and initiate at unconventional regions, outside promoters or enhancers. Here, we probe these unassigned TSSs and show that, in all species studied, a significant fraction of CAGE peaks initiate at microsatellites, also called short tandem repeats (STRs). To confirm this transcription, we develop Cap Trap RNA-seq, a technology which combines cap trapping and long read MinION sequencing. We train sequence-based deep learning models able to predict CAGE signal at STRs with high accuracy. These models unveil the importance of STR surrounding sequences not only to distinguish STR classes, but also to predict the level of transcription initiation. Importantly, genetic variants linked to human diseases are preferentially found at STRs with high transcription initiation level, supporting the biological and clinical relevance of transcription initiation at STRs. Together, our results extend the repertoire of non-coding transcription associated with DNA tandem repeats and complexify STR polymorphism

Microcracking and mechanical properties of YBa2Cu3Ox ceramics

Elasticity, hardness and fracture data have been measured on superconducting YBa, Cu3 O~ ceramics with a relative density ranging from 87 to 93% and a grain size from about 10 to 2411m. For the 93% dense material a value of 112 GPafor the Young’s modulus and a hardness value of about 4.5 GPa are obtained. The strength andfracture toughness are dependent on cooling rate. A strength of 86 and 117 MPa are obtained for ‘fast’ and ‘slow’ cooling rates respectively. The corresponding fracture toughness measurements yielded 1•2 and 1•4 MPa. m1. The fracture toughness can be sign~cantly lower, as observed on some specimens, probably by reaction with water at the grain boundaries. Extensive microcracking, in agreement with theoretical expectations, was observed by microscopy. Further evidence from mercury intrusion porosimetry and N, adsorption analysis is presented. Possible consequences are discussed

Adhesion of electrolessly deposited nickel-phosphorus on alumina ceramic : an assessment of the current status

Literature data on the adhesion of electrolessly deposited Ni(P) films on alumina ceramic substrates are reviewed in this paper. The influences of conditions of successive etching, nucleation and metallization processes on adhesion are discussed as well as the effect of subsequent annealing treatments. Also, a comparison is made with the adhesion of electrolessly deposited Ni(B) and Cu layers. In general, too little information is provided by most authors on the adhesion measurement conditions and procedures. It has been concluded that etching is more important for adhesion than nucleation, metallization and annealing, and it is commonly believed that mechanical interlocking is the dominant adhesion mechanism. However, bilayer experiments with electrolessly deposited Ni(P) and Cu suggest that the intimacy of interfacial contact plays an additional role. This may indicate that van der Waals or other interfacial interactions significantly contribute to adhesion. In order to obtain further insight into the adhesion mechanism, a fracture mechanics characterization is suggested. Modern surface analytical techniques should be applied to study interfaces and fracture surfaces

Microcracking and mechanical properties of YBa2Cu3Ox ceramics

Elasticity, hardness and fracture data have been measured on superconducting YBa, Cu3 O~ ceramics with a relative density ranging from 87 to 93% and a grain size from about 10 to 2411m. For the 93% dense material a value of 112 GPafor the Young’s modulus and a hardness value of about 4.5 GPa are obtained. The strength andfracture toughness are dependent on cooling rate. A strength of 86 and 117 MPa are obtained for ‘fast’ and ‘slow’ cooling rates respectively. The corresponding fracture toughness measurements yielded 1•2 and 1•4 MPa. m1. The fracture toughness can be sign~cantly lower, as observed on some specimens, probably by reaction with water at the grain boundaries. Extensive microcracking, in agreement with theoretical expectations, was observed by microscopy. Further evidence from mercury intrusion porosimetry and N, adsorption analysis is presented. Possible consequences are discussed