Rationally construction of atomic-precise interfacial charge transfer channel and strong build-in electric field in nanocluster-based Zscheme heterojunctions with enhanced photocatalytic hydrogen production

The lack of effective charge transfer driving force and channel limits the electron directional migration in nanoclusters(NC)-based heterostructures,resulting in poor photocatalytic performance.Herein,a Z-scheme NC-based heterojunction(Pt1Ag28-BTT/CoP,BTT=1,3,5-benzenetrithiol)with strong internal electric field is constructed via interfacial Co-S bond,which exhibits an absolutely superiority in photocatalytic performance with 24.89 mmol·h^(−1)·g−1 H_(2)production rate,25.77%apparent quantum yield at 420 nm,and~100%activity retention in stability,compared with Pt1Ag28-BDT/CoP(BDT=1,3-benzenedithiol),Ag29-BDT/CoP,and CoP.The enhanced catalytic performance is contributed by the dual modulation strategy of inner core and outer shell of NC,wherein,the center Pt single atom doping regulates the band structure of NC to match well with CoP,builds internal electric field,and then drives photogenerated electrons steering;the accurate surface S modification promotes the formation of Co-S atomic-precise interface channel for further high-efficient Z-scheme charge directional migration.This work opens a new avenue for designing NC-based heterojunction with matchable band structure and valid interfacial charge transfer.

Synergy of phosphorus vacancies and build-in electric field into NiCo/NiCoP Mott-Schottky integrated electrode for enhanced water splitting performance

Vacancy engineering and Mott-Schottky heterostructure can accelerate charge transfer,regulate adsorption energy of reaction intermediates,and provide additional active sites,which are regarded as valid means for improving catalytic activity.However,the underlying mechanism of synergistic regulation of interfacial charge transfer and optimization of electrocatalytic activity by combining vacancy and Mott-Schottky junction remains unclear.Herein,the growth of a bifunctional NiCo/NiCoP Mott-Schottky electrode with abundant phosphorus vacancies on foam nickel(NF)has been synthesized through continuous phosphating and reduction processes.The obtained NiCo/NiCoP heterojunctions show remarkable OER and HER activities,and the overpotentials for OER and HER are as low as 117 and 60 mV at 10 mA/cm^(2) in 1 mol/L KOH,respectively.Moreover,as both the cathode and anode of overall water splitting,the voltage of the bifunctional NiCo/NiCoP electrocatalyst is 1.44 V at 10 mA/cm^(2),which are far exceeding the benchmark commercial electrodes.DFT theoretical calculation results confirm that the phosphorus vacancies and build-in electric field can effectively accelerate ion and electron transfer between NiCo alloy and NiCoP semiconductor,tailor the electronic structure of the metal centers and lower the Gibbs free energy of the intermediates.Furthermore,the unique self-supported integrated structure is beneficial to facilitate the exposure of the active site,avoid catalyst shedding,thus improving the activity and structural stability of NiCo/NiCoP.This study provides an avenue for the controllable synthesis and performance optimization of Mott-Schottky electrocatalysts.

Network-based products detection system:congestion control and self diagnosis

The problems that arise while developing a real-time distributed information-processing software system are studied. And based on the TCP/IP protocols and socket, for its facility in client/server （C/S） model networking programming, a prototype is designed for data transmission between the server and clients and it is applied on an on-line products automatic detection system. The probability analysis on network congestion was also made. A proper mechanism based on the ARCC （adapted RTT congestion control） algorithm is employed for detecting and resolving congestion, the purpose of which is mainly to achieve congestion avoidance under the particular conditions in this network-based system and reach the desired performance. Furthermore, a method is proposed for a client to diagnose automatically the connection status between the server and the client and to re-connect to the server when the disconnection is detected.

Health Seeking Behavior among Medical Students in the University of Sharjah

Background： Medical students have different perception of symptoms and illness. Moreover, medical students reportbarriers to seeking help about their health, and are more likely to seek advice informally from friends and/or family. It is important toidentify health seeking behaviors among medical students to be able to modify and interfere accordingly. Objectives： To describe thehealth seeking behavior of medical students in UOS and identify the factors affecting those behaviors. Methods： A cross-sectionalstudy was conducted at the University of Sharjah during the spring semester of the academic year 2012-2013. Self-administeredquestionnaires were distributed to all medical students from all 5 years. Questions were related to physical health seeking behaviorsonly. Data was analyzed using the SPSS21 software. Results： We have found that self-prescription was the most common practicedhealth seeking behavior among 91.8%-96.6% of UOS medical students （CI of 95%） followed by the order ignoring a health problem,seeking immediate care, using the internet, reading more about the problem and self diagnosis ＆ management. All are practiced bymore than 50% of the students. A set of other behaviors was identified as well. Factors affecting these behaviors mainly included：self-care orientation ＆ medical education. Other factors that had a role as well were： gender, stage of studying, having a chronic illnessand lack of knowledge about the health services available. Conclusions： Medical students in the University of Sharjah have a high levelof self-care orientation and accordingly, tend to react to their illness in a variety of ways. The most common of these is self-prescription.Studying medicine is the 2nd major factor that influences their health seeking behaviors. Sufficient guidance about the consequencesassociated with certain behaviors may be required.

Microscopic mechanism of imprint in hafnium oxide-based ferroelectrics

Hafnia-based ferroelectrics have greatly revived the field of ferroelectric memory(FeRAM),but certain reliability issues must be satisfactorily resolved before they can be widely applied in commercial memories.In particular,the imprint phenomenon severely jeopardizes the read-out reliability in hafnia-based ferroelectric capacitors,but its origin remains unclear,which hinders the development of its recovery schemes.In this work,we have systematically investigated the imprint mechanism in TiN/Hf_(0.5)Zr_(0.5)O_(2)(HZO)/TiN ferroelectric capacitors using experiments and first-principles calculations.It is shown that carrier injection-induced charged oxygen vacancies are at the heart of imprint in HZO,where other mechanisms such as domain pinning and dead layer are less important.An imprint model based on electron de-trapping from oxygen vacancy sites has been proposed that can satisfactorily explain several experimental facts such as the strong asymmetric imprint,leakage current variation,and so forth.Based on this model,an effective imprint recovery method has been proposed,which utilizes unipolar rather than bipolar voltage inputs.The remarkable recovery performances demonstrate the prospect of improved device reliability in hafnia-based FeRAM devices.

Analytical models for the base transit time of a bipolar transistor with double base epilayers

The doping profile function of a double base epilayer is constructed according to drift-diffusion theory. Then an analytical model for the base transit time τb is developed assuming a small-level injection based on the characteristics of the 4H-SiC material and the principle of the 4H-SiC BJTs. The device is numerically simulated and validated based on two-dimensional simulation models. The results show that the built-in electric field generated by the double base epilayer configuration can accelerate the carriers when transiting the base region and reduce the base transit time. From the simulation results, the base transit time reaches a minimal value when the ratio of L2/L1 is about 2.

Repair the faulty TSVs with the improved FNS-CAC codec

Through-silicon via(TSV)is a key enabling technology for the emerging 3-dimension(3 D)integrated circuits(ICs).However,the crosstalk between the neighboring TSVs is one of the important sources of the soft faults.To suppress the crosstalk,the Fibonacci-numeral-system-based crosstalk avoidance code(FNS-CAC)is an effective scheme.Meanwhile,the self-repair schemes are often used to deal with the hard faults,but the repaired results may change the mapping between signals to TSVs,thus may reduce the crosstalk suppression ability of FNS-CAC.A TSV self-repair technique with an improved FNS-CAC codec is proposed in this work.The codec is designed based on the improved Fibonacci numeral system(FNS)adders,which are adaptive to the health states of TSVs.The proposed self-repair technique is able to suppress the crosstalk and repair the faulty TSVs simultaneously.The simulation and analysis results show that the proposed scheme keeps the crosstalk suppression ability of the original FNS-CAC,and it has higher reparability than the local self-repair schemes,such as the signal-switching-based and the signal-shifting-based counterparts.

Perovskite solar cells: recent progress and strategies developed for minimizing interfacial recombination

Organometallic perovskite is a new generation photovoltaic material with exemplary properties such as high absorption co-efficient,optimal bandgap,high defect tolerance factor and long carrier diffusion length.However,suitable electrodes and charge transport materials are required to fulfill photovoltaic processes where interfaces between hole transport material/perovskite and perovskite/electron transport material are affected by phenomena of charge carrier separation,transportation,collection by the interfaces and band alignment.Based on recent available literature and several strategies for minimizing the recombination of charge carriers at the interfaces,this review addresses the properties of hole transport materials,relevant working mechanisms,and the interface engineering of perovskite solar cell(PSC)device architecture,which also provides significant insights to design and development of PSC devices with high efficiency.