A regioselectivity switch in Pd-catalyzed hydroallylation of alkynes.

By exploiting the reactivity of a vinyl-Pd species, we control the regioselectivity in hydroallylation of alkynes under Pd-hydride catalysis. A monophosphine ligand and carboxylic acid combination promotes 1,5-dienes through a pathway involving isomerization of alkynes to allenes. In contrast, a bisphosphine ligand and copper cocatalyst favor 1,4-dienes via a mechanism that involves transmetalation. Our study highlights how to access different isomers by diverting a common organometallic intermediate

Tetra­kis[μ3-4-nitro-N-(5-phenyl-1,3,4-oxadiazol-2-yl)benzamidato]tetra­kis­[methano­lsodium(I)]

In the title compound, [Na4(C15H9N4O4)4(CH3OH)4], the N3O3 environment around the Na+ ion is distorted octa­hedral. In the unit cell, four Na+ ions are bridged by four Schiff base anions, leading to a tetra­nuclear complex with -4 symmetry. O—H⋯N hydrogen bonds between the methanol mol­ecule and the Schiff base anion stabilize the structural set-up

Leaders’ response to employee overqualification:An explanation of the curvilinear moderated relationship

This research aimed to advance overqualification literature by examining how leaders’ perceived employee overqualification (LPEO) influences their empowering behaviour and employee work behaviours. Drawing upon the individualized leadership theory, we proposed that LPEO has an inverted U-shape relationship with their empowering behaviour such that leaders are more motivated to empower employees from low to moderate levels of overqualification, but this tendency decreases after a certain inflection point. We also predicted that the inflection point occurs at a lower level of employee overqualification when leaders perceive higher (vs. lower) status threats. Leader empowering behaviour was hypothesized to positively predict employees’ voice and negatively predict their withdrawal behaviour. Two multi-source and time-lagged studies were conducted to examine this moderated mediation curvilinear model. In Study 1, survey data from 372 leader–employee dyads supported the inverted U-shape mediation model from leaders’ perceived overqualification to empowering behaviour, then to employee outcomes (i.e., voice and withdrawal behaviour). In Study 2, we collected data from a sample of 73 team leaders and 286 employees, and the results supported the full model. Taken together, these findings offer a perspective to enrich the understanding of employee overqualification and have important practical implications.Practitioner pointsWhen leaders regard employees as overqualified, they can assist them via the means of appropriate empowerment to best utilize their skills to benefit the company.Leader empowerment can inspire employees’ voice behaviour but reduce their withdrawal behaviours.To minimize potentially negative aspects from highly overqualified employees, organizations should reduce leaders’ concern about the status threat, and encourage leaders’ proactive responses to these employees so as to achieve positive returns from overqualified employees

Leaders’ response to employee overqualification:An explanation of the curvilinear moderated relationship

This research aimed to advance overqualification literature by examining how leaders’ perceived employee overqualification (LPEO) influences their empowering behaviour and employee work behaviours. Drawing upon the individualized leadership theory, we proposed that LPEO has an inverted U-shape relationship with their empowering behaviour such that leaders are more motivated to empower employees from low to moderate levels of overqualification, but this tendency decreases after a certain inflection point. We also predicted that the inflection point occurs at a lower level of employee overqualification when leaders perceive higher (vs. lower) status threats. Leader empowering behaviour was hypothesized to positively predict employees’ voice and negatively predict their withdrawal behaviour. Two multi-source and time-lagged studies were conducted to examine this moderated mediation curvilinear model. In Study 1, survey data from 372 leader–employee dyads supported the inverted U-shape mediation model from leaders’ perceived overqualification to empowering behaviour, then to employee outcomes (i.e., voice and withdrawal behaviour). In Study 2, we collected data from a sample of 73 team leaders and 286 employees, and the results supported the full model. Taken together, these findings offer a perspective to enrich the understanding of employee overqualification and have important practical implications.Practitioner pointsWhen leaders regard employees as overqualified, they can assist them via the means of appropriate empowerment to best utilize their skills to benefit the company.Leader empowerment can inspire employees’ voice behaviour but reduce their withdrawal behaviours.To minimize potentially negative aspects from highly overqualified employees, organizations should reduce leaders’ concern about the status threat, and encourage leaders’ proactive responses to these employees so as to achieve positive returns from overqualified employees

Acoustic emission source location method and experimental verification for structures containing unknown empty areas

Acoustic emission (AE) localization plays an important role in the prediction and control of potential hazardous sources in complex structures. However, existing location methods have less discussion on the presence of unknown empty areas. This paper proposes an AE source location method for structures containing unknown empty areas (SUEA). Firstly, this method identifies the shape, size, and location of empty areas in the unknown region by exciting the active AE sources and using the collected AE arrivals. Then, the unknown AE source can be located considering the identified empty areas. The lead break experiments were performed to verify the effectiveness and accuracy of the proposed method. Five specimens were selected containing empty areas with different positions, shapes, and sizes. Results show the average location accuracy of the SUEA increased by 78% compared to the results of the existing method. It can provide a more accurate solution for locating AE sources in complex structures containing unknown empty areas such as tunnels, bridges, railroads, and caves in practical engineering

Practice Teaching System Establishment in the Major of Tourism Management

Based on the review of related national and international literature, it illustrated the current condition of practice teaching in the major of tourism management in China, specifically analyzed the existing problems, and then established the practice teaching system on the basis of competency based education (CBE), which include system establishing principles, system contents and measures to carry out the system.

Observing white dwarf tidal stripping with TianQin gravitational wave observatory

Recently discovered regular X-ray bursts known as quasi-periodic eruptions have a proposed model that suggests a tidal stripping white dwarf inspiralling into the galaxy's central black hole on an eccentric orbit. According to this model, the interaction of the stripping white dwarf with the central black hole would emit gravitational wave signals as well, their detection can help explore the formation mechanism of quasi-periodic eruptions and facilitate multi-messenger observations. In this paper, we aim to perform a preliminary study of the gravitation wave observation of TianQin on this stripping white dwarf model. We investigated the horizon distance of TianQin on this type of gravitation wave signal and found it can be set to 200Mpc. We also find that those stripping white dwarf model sources with central black hole mass within $10^4\sim10^{5.5}M_\odot$ are more likely to be detected by TianQin. We assessed the parameter estimation precision of TianQin on those stripping white dwarf model sources. Our result shows that, even in the worst case, TianQin can determine the central black hole mass, the white dwarf mass, the central black hole spin, and the orbital initial eccentricity with a precision of $10^{-2}$. In the optimistic case, TianQin can determine the central black hole mass and the white dwarf mass with a precision of $10^{-7}$, determine the central black hole spin with a precision of $10^{-5}$, and determine the orbital initial eccentricity with a precision of $10^{-8}$. Moreover, TianQin can determine the luminosity distance with a precision of $10^{-1}$ and determine the sky localization with a precision of $10^{-2}\sim10$ $\rm deg^2$.Comment: 9 pages, 4 figure