Thermoelectric (TE) Device made using PbTe Nanocrystal Coated Glass Fibers

Around 60 % of the energy produced in the U.S. in 2013 was wasted and most of this was dissipated in the form of heat. Thermoelectric materials could potentially harvest part of the energy being wasted by converting heat energy into electrical energy. Lead telluride nanocrystals are an interesting thermoelectric material particularly for solution-based coating of flexible substrates. The purpose of this project is to develop a working thermoelectric device using p-n pairs of PbTe nanocrystal coated glass fibers. In this project, p- and n- type PbTe nanocrystals are synthesized in solution. Bare glass fibers are sequentially dipped in solutions of PbTe nanocrystals to form a layer of PbTe, diluted aqueous hydrazine to remove organic ligands, and acetonitrile to wash away the hydrazine. The procedure is repeated to achieve a sufficiently thick nanocrystal coating on the glass fibers. The coated glass fibers are then used to make a prototype thermoelectric device with alternating p-type and n-type segments placed electrically in series and thermally in parallel. The device is placed in a temperature gradient and the resistance, current, voltage, and power output are measured. We found that the device has a resistance of approximately 33 MΩ and generates a power output of 5.3 pW in a temperature gradient of 20 Kelvin

Interfacial Dzyaloshinskii-Moriya interaction and spin-orbit torque in Au1-xPtx/Co bilayers with varying interfacial spin-orbit coupling

The quantitative roles of the interfacial spin-orbit coupling (SOC) in Dzyaloshinskii-Moriya interaction (DMI) and dampinglike spin-orbit torque ({\tau}DL) have remained unsettled after a decade of intensive study. Here, we report a conclusive experiment evidence that, because of the critical role of the interfacial orbital hybridization, the interfacial DMI is not necessarily a linear function of the interfacial SOC, e.g. at Au1-xPtx/Co interfaces where the interfacial SOC can be tuned significantly via strongly composition (x)-dependent spin-orbit proximity effect without varying the bulk SOC and the electronegativity of the Au1-xPtx layer. We also find that {\tau}DL in the Au1-xPtx/Co bilayers varies distinctly from the interfacial SOC as a function of x, indicating no important {\tau}DL contribution from the interfacial Rashba-Edelstein effect

Evaluation of a Community-Based Positive Youth Development Program in Hong Kong: Views of Program Implementers

Using a subjective outcome evaluation method, the current study investigated program implementers’ perceptions of the Tier 1 Program of the community-based P.A.T.H.S. Project in Hong Kong. After completion of the program, 599 program implementers completed a valid and reliable scale (i.e. Form B) to give their ratings on program content, their own performance, and perceived program effectiveness. As expected, most program implementers perceived the program in a favorable way by giving very positive ratings on the three aspects measured in Form B. Grade differences on the ratings were observed, with implementers teaching the senior curriculum held more positive views on program effectiveness than did those teaching the junior curriculum. Similar to previous findings, perceived program content and perceived worker performance predicted program effectiveness. Findings of the present study provide further evidence for the success of the Tier 1 Program of the community-based P.A.T.H.S. Project in Hong Kong

Integration of the Confucian Culture on Cross-Cultural Conflict Management: The Role of the COVID-19 Pandemic

Cross-culture conflict management is the major challenge for the Chinese enterprises going global along the Belt and Road Initiative. This study explores the feasibility of integrating the Confucian culture into cross-culture conflict management, and a special role is given to the COVID-19 pandemic. We combine the Confucian culture values and Hofstede’s cultural dimension theory and adopt the questionnaire survey methods on the Chinese multinational enterprises’ employees. The Cronbach’s Alpha method is also deployed to test the reliability and validity of the data. We find the significant integration of the Confucian culture into cross-culture conflict management. Furthermore, 16 sub-values of the Confucian culture are suggested to mitigate the cross-culture conflicts in multinational enterprises effectively. The findings imply that Chinese enterprises should consider new strategies to manage the cross-culture conflicts, especially during the COVID-19 pandemic

Reciprocal Relationships Between Moral Competence and Externalizing Behavior in Junior Secondary Students: A Longitudinal Study in Hong Kong

Defining moral competence using a virtue approach, this longitudinal study examined the prospective relationships between moral competence and externalizing behavior indexed by delinquency and intention to engage in problem behavior in a large and representative sample of Hong Kong Chinese adolescents. Starting from the 2009–2010 academic year, Grade 7 students in 28 randomly selected secondary schools in Hong Kong were invited to join a longitudinal study, which surveyed participating students annually during the high school years. The current study used data collected in the first 3 years (Wave 1 to Wave 3) across junior secondary school stage (Grades 7–9) with a sample of 3,328 students (Age = 12.59 ± 0.74 years and 52.1% boys at Wave 1). Cross-lagged panel path analyses were conducted to compare four models involving different hypothesized patterns of relationships between moral competence and externalizing behavior. Results revealed that the reciprocal effects model best fit the data, supporting reciprocal causal relationships between moral competence and externalizing behavior measures. Specifically, a higher level of moral competence significantly predicted a lower level of delinquency and problem behavioral intention over time. At the same time, a higher level of externalizing behavior also significantly predicted a lower level of moral competence 1 year later. As the magnitudes of the significant findings were not high, replications in different Chinese communities are needed. Nevertheless, the present findings provide important theoretical insights on how moral competence and externalizing behavior in adolescents are associated with each other. Practically speaking, the findings suggest that it is promising to reduce adolescent externalizing behavior by promoting their virtues through moral education programs, and guiding adolescents to behave in a good manner would help promote the development of their virtues

Sideband pump-probe technique resolves nonlinear modulation response of PbS/CdS quantum dots on a silicon nitride waveguide

For possible applications of colloidal nanocrystals in optoelectronics and nanophotonics, it is of high interest to study their response at low excitation intensity with high repetition rates, as switching energies in the pJ/bit to sub-pJ/bit range are targeted. We develop a sensitive pump-probe method to study the carrier dynamics in colloidal PbS/CdS quantum dots deposited on a silicon nitride waveguide after excitation by laser pulses with an average energy of few pJ/pulse. We combine an amplitude modulation of the pump pulse with phase-sensitive heterodyne detection. This approach permits to use co-linearly propagating co-polarized pulses. The method allows resolving transmission changes of the order of 10(-5) and phase changes of arcseconds. We find a modulation on a sub-nanosecond time scale caused by Auger processes and biexciton decay in the quantum dots. With ground state lifetimes exceeding 1 mu s, these processes become important for possible realizations of opto-electronic switching and modulation based on colloidal quantum dots emitting in the telecommunication wavelength regime

On the special oxidation mechanism of a Mg-Y-Al alloy contained LPSO phase at high temperatures

This work investigated the oxidation of Mg-11Y-1Al alloy in Ar-20%O2 at 500{\deg}through multiscale characterization. The results show that the network-like long-period stacking ordered(LPSO) phase decomposed into a needle-like LPSO phase and a polygonal Mg24Y5 phase. The needle-like LPSO phase resulted in the formation of a high-dense of needle-like oxide at the oxidation front of the area initially occupied by the network-like LPSO phase. The further inward oxygen would diffuse along the needle-like oxide-matrix interfaces and react with Y in the surrounding Mg matrix, resulting in the lateral growth of these needle-like oxides. Finally, the discrete needle-like oxides were interconnected to form a thicker and continuous oxide scale which could be more effective in hindering the elemental diffusion. Meanwhile, Al could partially enter the Y2O3 oxide scale and formed a strengthened (Y,Al)O oxide scale which could show a greater resistance to cracking and debonding