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.

现制防水技术在混凝土建筑中的应用

混凝土建筑密封防水领域大量采用防水卷材制作防水层,传统防水卷材形变能力较,差易形成空鼓,施工搭接边部位防水能力薄弱,且施工质量受限于施工人员的经验水平,漏水隐患大。提出采用现场施工的方式制得卷材防水层,形成的防水层通过化学和物理的交联作用实现与混凝土基面的满粘效果,克服传统防水卷材存在与基面粘结不牢的问题,实现全密封防水。介绍了现制防水技术的工程应用实例。

超细沸石粉对水泥净浆结构构筑的影响

超细沸石粉是经过天然沸石研磨而得, 比水泥具有更高的细度, 火山灰活性高于粉煤灰和矿粉, 低于硅灰和偏高 岭土。静态屈服应力是水泥基材料一个重要的流变参数。静态屈服应力增长速率经常被用来表征水泥基材料的触变性 /结构构筑,对水泥基材料的稳定性、形状保持能力和分层浇注非常重要。在本文静态屈服应力每15min测试一次,持续 127min。同时进行了动态屈服应力测试。结果表明掺入超细沸石粉提高了浆体的动态屈服应力、 塑性粘度和触变环面积。 在等掺量的情况下,超细沸石粉提升结构构筑的能力低于硅灰和偏高岭土。

线上线下结合教学模式在建筑给水排水工程教学中的应用

建筑给水排水工程作为建筑设备安装技术专业群中多个专业共享的专业核心课程,对学生实践能力要求很高。将线上线下结合的教学模式应用在建筑给水排水工程教学中,能够为学生提供新的个性化的学习平台,实现线上知识输入、线下及时输出,让知识真正内化,达到“知行合一”的学习效果。

浅谈“三下”采煤技术

在建筑物下、水体下和铁路下“三下”采煤必须具备一定的条件要求 ,且要采取不同的技术措施 ,保证建筑物、铁路。

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.

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.

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.