Kinds Of Contacts Research Articles

The Strength of Many Kinds of Ties: Unpacking the Role of Social Contacts Across Stages of the Job Search Process

The topic of job mobility has received increasing attention in recent years. Yet, surprising in light of the wealth of research on social networks and job attainment, we do not have a unified model of the impact of different kinds of social contacts on job search success. In this paper I show that contacts are differently beneficial for job seekers depending on the stage of the job search process that job seekers are engaged in. Specifically, three stages of the job search process can be distinguished in which social contacts fulfill different roles for the job seekers: deciding the types of jobs for which to apply, submitting job applications, and preparing for interviews. I propose that contacts who are spread across different occupations are conducive to applying to more types of jobs, yet it is contacts who are more focused across occupations that are beneficial for being invited to more interviews—relative to the number of job types applied for—and for converting the interviews into offers. In addition, contacts with lower relationship depth with the job seeker are more helpful for getting invited to interviews, whereas contacts who have more frequent interactions with the job seeker are more helpful for converting interviews into offers. Analyses using a unique longitudinal data set on the job searches of 226 participants in an MBA program offer robust evidence in support of the hypotheses. The results suggest that external mobility is best enabled when job seekers engage with—and learn from—different kinds of contacts across stages of the job search process.

Investigation of <italic>Re</italic>BCO Conductor Tape Joints for Superconducting Applications

Electric joints are an essential part of every current carrying device. In the field of high temperature superconducting applications, quality of a contact between superconducting tapes and electric terminations is crucial for the device performance. When connecting tapes to each other, soldered contacts are commonly used. Recent reports have demonstrated that the resistance of this contact depends on the pressure applied during a soldering process, and the soldering temperature. When superconducting tapes are used in cables or in other applications, they have to be connected to copper terminations, e.g., to a current lead. Thus, tape-to-copper contacts are important. In superconducting cables, tapes are stacked together having a resistive electrical contact from tape to tape. The resistance of this contact depends on the pressure applied on the stack due to, for example, jacketing of the cable or during cool down. In this paper, the dependence of resistance between tapes on the applied pressure is reported. In this contribution two kinds of contacts, soldered ones and mechanical pressed, are presented and discussed. They are realized, respectively, between two superconducting ReBCO tapes from SuperPower, Inc. (SPI) and SuNAM, which were used for manufacturing HTS cable, and between superconducting tapes and copper.

UV-induced SiC nanowire sensors

Ultraviolet (UV)-induced sensors based on a single SiC nanowire (NW) were fabricated and the photoelectric properties including I–V characteristics and time response of the UV sensors were studied. SiC NWs (NWs) were prepared through pyrolyzing a polymer precursor with ferrocene as the catalyst by a CVD route. To elucidate the physical mechanism giving rise to the photoelectrical response in SiC NW sensors, three kinds of contacts between electrodes and SiC NW were prepared, i.e. Schottky contact, p–n junction contact, and Ohmic contact. The photoelectric measurements of the device with Schottky contact indicates the lowest dark current and the largest photocurrent. The results suggest that photocurrent generated at SiC NW-electrode contacts is a result of the photovoltaic effect, in which a built-in electric field accelerates photo generated charge carriers to the electronic contacts. The UV sensors based on SiC NWs could be applied in a harsh environment due to the excellent physical stability and photoelectric properties.

Post-derailment dynamic behavior of railway vehicles travelling on a railway bridge during an earthquake

This study developed a post-derailment dynamic model of railway vehicles to investigate their post-derailment dynamic behavior when travelling on a railway bridge during an earthquake. The model is composed of three parts: multi-body dynamic model of the railway vehicle, a collision detection model, and a contact force model. The dynamic model considered all the various kinds of contacts that may occur during the derailment, such as wheel/track slab contacts, wheel/fastener contacts, and brake-disc/rail contacts. A collision detection model that was based on the tight-fitting oriented bounding box trees approach was adopted to detect the collision situations during the derailment. The contact force model was used to calculate the contact force based on a Hertz spring-damper and the Coulomb friction law. Using this model, the post-derailment dynamic behavior of railway vehicles travelling on a railway bridge experiencing earthquake excitations was investigated. First, a seismic response analysis of the railway bridge was conducted in order to obtain the seismic response of the railway bridge; it was subsequently used as the input to the post-derailment dynamic model. Then the derailment postures of the vehicle and contact situations were fully analyzed to understand the post-derailment dynamic behavior of railway vehicles during the earthquake. The obtained results show that the brake disc adopted in the model has the ability to limit the deviation of the wheelsets after the derailment.

New Insights into Bacterial Chemoreceptor Array Structure and Assembly from Electron Cryotomography

Bacterial chemoreceptors cluster in highly ordered, cooperative, extended arrays with a conserved architecture, but the principles that govern array assembly remain unclear. Here we show images of cellular arrays as well as selected chemoreceptor complexes reconstituted in vitro that reveal new principles of array structure and assembly. First, in every case, receptors clustered in a trimers-of-dimers configuration, suggesting this is a highly favored fundamental building block. Second, these trimers-of-receptor dimers exhibited great versatility in the kinds of contacts they formed with each other and with other components of the signaling pathway, although only one architectural type occurred in native arrays. Third, the membrane, while it likely accelerates the formation of arrays, was neither necessary nor sufficient for lattice formation. Molecular crowding substituted for the stabilizing effect of the membrane and allowed cytoplasmic receptor fragments to form sandwiched lattices that strongly resemble the cytoplasmic chemoreceptor arrays found in some bacterial species. Finally, the effective determinant of array structure seemed to be CheA and CheW, which formed a “superlattice” of alternating CheA-filled and CheA-empty rings that linked receptor trimers-of-dimer units into their native hexagonal lattice. While concomitant overexpression of receptors, CheA, and CheW yielded arrays with native spacing, the CheA occupancy was lower and less ordered, suggesting that temporal and spatial coordination of gene expression driven by a single transcription factor may be vital for full order, or that array overgrowth may trigger a disassembly process. The results described here provide new insights into the assembly intermediates and assembly mechanism of this massive macromolecular complex.

Single‐Crystal X‐ray Diffraction and Solution Studies of Anion–π Interactions in N‐(Pentafluorobenzyl)pyridinium Salts

AbstractA solid‐state structural study on anion–π interaction in various N‐(pentafluorobenzyl)pyridinium salts accompanied by NMR spectroscopic investigations is presented. The crystal structures of 1a–1d reveal different kinds of contacts with anions, including anion–π interactions. In particular, the solid‐state structure of 1b‐I3 shows distinct evidence of anion–π interactions. Attempts to study anion–π interactions in solution were not successful, but their presence in solution could not be ruled out.

Rich Ties and Innovative Knowledge Transfer within a Firm

We show that contacts in formal, informal and especially multiplex networks explain transfer of innovative knowledge in an organization. The contribution of informal contacts has been much acknowledged, while that of formal contacts did not receive much attention in the literature in recent decades. No study thus far has included both these different kinds of contacts in a firm, let alone considered their combined effect. The exact overlap between formal as well as informal contacts between individuals, forming multiplex or what we call rich ties because of their contribution, especially drives the transfer of new, innovative knowledge in a firm. Studying two cases in very different settings suggests these rich ties have a particularly strong effect on knowledge transfer in an organization, even when controlling for the strength of ties. Some of the effects on knowledge transfer in an organization previously ascribed to either the formal network or the informal network may actually be due to their combined effect in a rich tie.

Contact analysis and modeling of a linear ultrasonic motor with a threaded output shaft

This paper presents a contact analysis and a mathematical model for a linear ultrasonic motor with a threaded output shaft. The motor utilizes an out-of-plane traveling wave and an in-plane traveling wave to drive the output shaft. Two kinds of contacts are analyzed and modeled respectively. A numerical model is developed to predict the performance and behavior of the motor, including the no-load speed, the maximum driving force, the maximum output power, and the effects of the thread pitch, the dynamic friction coefficient, the mean thread radius on motor performance. A prototype motor is fabricated and experimental testing is performed to compare the experimental results with the predictions from models. The model developed here can be used as a design tool for designing and optimizing the linear ultrasonic motor with a threaded output shaft.

Religious Mobility in the Roman Empire

AbstractThe spread of religions throughout the Roman world may be explained partly as a consequence of the movements of peoples, partly in terms of the emergence of new elective cults. Understanding these processes entails exploring the kinds of contacts and exchanges established between individual worshippers, and the contexts — local and imperial — within which they took place. These developments culminated in the emergence of new cults that spilled over the boundaries of the Roman Empire to create the first global religions.

Binding Energy of Carbon Implanted into Hematite and in situ Observation of Reaction Behavior during Heating Up Experiment

It is widely known that the direct contact between solid carbon and iron oxide shows quite a fast reduction rate in comparison with CO gas reduction. However, it is difficult to sustain the physical contact between solid carbon and iron oxide. Furthermore, the contact mode will be different from the production method, which will affect the reaction kinetics strongly. In this study, different kinds of contacts between solid carbon and hematite were made to clarify the reaction mechanism. One contact mode is the deposition of the carbon layer on the hematite surface using a vacuum evaporation method. Another method is the implantation of carbon ions into hematite. Using XPS (X-ray photoelectron spectroscopy), the binding energy of Fe–O–C was measured. Heating under an argon atmosphere was carried out. Both samples showed quite different reaction behavior, though the temperature at the beginning of the reduction reaction was almost the same. From these results, it was determined that the position of carbon will change the reaction behavior drastically, because it is important how the CO gas escapes from the reaction site.

Editorial

The early modern period of world history (ca. 1300-1800) was marked by a rapidly increasing level of global interaction. Between the aftermath of Mongol conquest in the East and the onset of industrialization in the West, a framework was established for new kinds of contacts and collective self-definition across an unprecedented range of human and physical geographies. The Journal of Early Modern History, the official journal of the University of Minnesota Center for Early Modern History, is the first scholarly journal dedicated to the study of early modernity from this world-historical perspective, whether through explicitly comparative studies, or by the grouping of studies around a given thematic, chronological, or geographic frame.

The electrical transport properties of Ag/Nd0.7Sr0.3MnO3 ceramic interface

The transport properties of interface between metal electrode and Nd0.7Sr0.3MnO3 bulk have been investigated under 2-wire measuring mode using permeating Ag and Ag-glue contact, respectively. The results show that, for the permeating Ag contact, the measured results are similar to that of 4-wire measurement, and an ohmic character is obtained without EPIR effect. However, a strongly nonlinear V-I curve appears and exhibits a stable EPIR effect for the Ag-glue contact. Besides, It also shows remarkable difference when loaded with alternating current for the two different kinds of contacts. For the former, the real part of impedance R' increases with increasing frequency which is attributable to the skin effect; for the latter, however, the R' is of about megohm order of magnitude and the R' peak decreases with increasing frequency. Moreover, the R' peak splits into two peaks which respectively move to high and low temperature when further increasing the frequency. In combination with the data of scanning electron microscopy, the differences of electrical transport are discussed.

Effect of surface pattern on the adhesive friction of elastomers

We present experimental results for the friction of a flat surface against a hexagonally patterned surface, both being made of PolyDiMethylSiloxane. We simultaneously measure forces of range 10 mN and observe the contact under sliding velocities of about 100 μm/s. We observe adhesive friction on three different pattern heights (80, 310, and 2100 nm). Two kinds of contacts have been observed: the flat surface is in close contact with the patterned one (called intimate contact, observed for 80 nm) or only suspended on the tops on the asperities (called laid contact, observed for 2100 nm). In the range of velocities used, the contact during friction is similar to the static one. Furthermore, our experimental system presents a contact transition during friction for h=310 nm.

A single-domain boundary element method for packed silencers with multiple bulk-reacting sound absorbing materials

Traditionally, the boundary element method only applies to problems with one single homogenous material in the domain. For acoustic problems in air, the homogeneous material is simply the air. When a problem involves two or more different homogeneous materials, the most common choice has been the multi-domain boundary element method, which matches the continuity conditions or certain special interface conditions between any two homogeneous sub-domains in contact. Although the multi-domain concept is straightforward, defining each sub-domain and matching the interface conditions at all kinds of contacts could become an issue when the subdomains are intricately connected to one another in a complex design. In addition, several imaginary interfaces may also have to be created to have well-defined subdomain boundary surfaces. To alleviate these difficulties, this paper presents a single-domain boundary element method for the acoustic analysis of packed silencers with multiple bulk-reacting sound-absorbing materials inside. This single-domain boundary element method does not define any subdomains, nor does it use any imaginary interfaces. It can handle as many materials as one can have. Numerical examples are compared to the available experimental data and the local-reacting normal impedance approximation.

Role of Nonpolar Amino Acid Functional Groups in the Surface Orientation-Dependent Adsorption of Natural and Synthetic Antifreeze Peptides on Ice

The aim of this study is to investigate the significance of nonpolar functional groups in the surface orientation-dependent adsorption of natural and synthetic antifreeze proteins (AFPs) on ice. We investigate using nanoliter osmometry, ice etching, and circular dichroism spectroscopy a series of nine designed α-helical peptides to probe the nature of their selectivity between the bipyramidal {201} and the secondary prismatic {210} faces of ice, identified earlier as the preferred faces for adsorption of winter flounder (WF) and shorthorn sculpin type I AFPs, respectively. Complementarities between the AFP’s surface features, comprised chiefly of nonpolar groups, and the well-defined sites on ice surface, allow close contact. Because our experimental studies demonstrate that the function of AFPs relies on participation of both polar and nonpolar residues in the ice surface adsorption, we carry out computational modeling to explore both kinds of contacts at the ice surface. On the basis of results of semi...

Palliative Versorgung bei Früh- und Reifgeborenen mit sehr ungünstiger Prognose

Involvement of the family in decisions to withhold or withdraw intensive care and parental involvement in care planning for terminally ill infants does not aggravate or prolong parents' grief responses, their feelings of guilt, or the incidence of pathological grief responses. Effective physical pain and symptom management is critically important. Compassionate care plans, however, need to implement a number of other and equally important components. Parents are not uniform in their perceived needs to make various kinds of contacts with their dying infant. They should be allowed to make their individual choices regarding contact with their baby during that time. The perinatal loss of a twin infant appears to evoke no less serious stress and risks to parents' compared to the loss of a singleton. The disruption of family life during a perinatal loss affects siblings of the baby, and their specific needs should be acknowledged. Post-death or post-autopsy meetings with the family should routinely be scheduled a few weeks after death, and bereavement support should actively be offered. Parents need to be informed about differences to be expected between maternal and paternal grief responses. The risk of pathological grief variants and chronic grief should be mentioned to parents because professional help is required in such occurrence.

Investigation on load-dependent roughness variations

In order to investigate the level of influence of roughness in the evaluation of the dimensionless film thickness Λ a study has been started to find a simplified but sufficiently general method to take into account the roughness variations of bodies, even with different characteristics, because of varying load. The investigation is based on a linear measured roughness profile. In this work, a model developed for the approximation of measured profiles through parabolas and formulas used for solving the contact mechanics problem are reported. The first results obtained with some specimens, used in previous works for experimental investigations on non-conformal line contacts, are presented. The specimens' surfaces are analysed both by a three-dimensional computer-controlled stylus profilometer and by an apparatus that allows investigations also under loaded conditions using optical interferometry. A way to compare the experimental and the theoretical results, in order to make some necessary verifications correlating line and surface aspects, is indicated. A first estimation of the variation of Λ under load is finally made. The method developed for the evaluation of roughness variations under load seems to furnish reasonable results in quite good agreement with the experimental ones. The results obtained with the investigated non-conformal line contacts, presenting characteristics in not complete agreement with the model-based hypotheses, give a certain confidence about the applicability of this simplified methodology to different kinds of contacts.

The p-to-n-type conversion of boron-doped diamond layers by deuteration: New findings

The p-to-n-type conversion of particular B-doped homoepitaxially grown diamond layers upon deuterium plasma treatment was discovered three years ago. However, many questions regarding the reproducibility of the effect for samples of different origins remain unanswered up to now, in particular the role of the electrical contacts and the possibility of a surface inversion layer being responsible for the n-type conductivity, the thermal stability and origin of the donor. Here we address the above questions. We show that the p-to-n conversion is closely related to the presence of defects, which can vary, on a macroscopic scale, in different regions of the same sample. The p-type regions containing a small concentration of defects are found to be converted to n-type upon deuteration. In contrast, the regions counting a high defect density exhibit very low p-type conductivity related to passivation of the boron acceptors by deuterium accompanied by a large uptake of D on defects. We show that the n-type conversion can be equally observed with three different kinds of contacts (silver paint, implanted and evaporated). We prove that the n-type conversion is a bulk effect and not a surface effect. We find that the thermal stability of the n-type complex is limited to temperatures lower than 200 °C. The temperature dependence of the carrier concentration measured by the Hall effect at different stages of the conversion process is fitted following the formalism describing the conduction mechanisms in a partially compensated semiconductor. The fact that the donor concentration in the as-deuterated state is very close to the boron concentration strongly suggests that the new-formed donor complexes contain both D and B.

Rheology of PVC Plastisol—V: Storage Modulus and Network Formed by Particle Contact

Our previous work with PVC plastisols showed that pseudo-plastic behavior under increasing frequency of dynamic measurement was a result of the development of an immobilized layer. Subsequently, the dynamic viscosity and the storage modulus of the mobile phase were evaluated. The samples consisted of fine and coarse particles, of which the fine/coarse ratio was varied. The present work relates the storage modulus at different frequencies to the fine/coarse ratio through a model network consisting of particle–particle contacts. The contacts are of three kinds, fine–fine (f-f), fine–coarse (f-c), and coarse–coarse (c-c). The average number of contact points per particle has been evaluated for the above kinds of contacts at different frequencies. Also, a number of particles participating in the network have been evaluated as a relative measure. At lower frequency relatively larger numbers of f-f contact points exist per particle but fewer numbers of particles participate in the network. Therefore, the network is rather loose. The f-c contact shows a similar trend but fewer contact points per particle at all frequency levels. The c-c contact is limited to a pair formation, i.e., only 0.5 contact point per particle on average. However, c-c contact contributes significantly to the magnitude of the modulus, because of the size of the particle. At the higher frequency there are fewer f-f contacts, but a larger number of particles are participating in the network. The trend with the f-c contact is very similar. The c-c contact increases significantly at the higher frequencies.

Si 1− xGe x/Si valence band offset determination using current–voltage characteristics

The valence band offset (Δ E V) between strained Si 1− x Ge x and Si can be determined by temperature-dependent current–voltage ( I– V– T) measurements on Si/Si 1− x Ge x /Si quantum wells (QW) using two kinds of contacts. Firstly, we used samples with ohmic contacts and with a simple theory of thermionic emission we estimated Δ E V=147±10 meV for x=0.17 and Δ E V=190±10 meV for x=0.22. Secondly, we investigated samples with Schottky contacts. The forward I– V– T characteristics show a normal Schottky diode behavior up to 0.5 V. Then the slope decreases strongly at higher voltages. This behavior was attributed to the effect of an additional barrier due to the band offset between Si and Si 1− x Ge x at the QW. From these measurements we estimated Δ E V=105±20 meV for x=0.17 and Δ E V=190±20 meV for x=0.22. It is shown that the Δ E V evaluated on samples with ohmic contacts are more reliable.