Characterization and coordination of intercalation - Non-intercalation phase transition in a new hybrid halide perovskite (n-C16H33NH3)2 ZnCl4

The ac conductivity σ(ω,T) and the complex dielectric permittivity ε^•(ω,T) as function of temperature 100 K < T < 400 K and frequency in the range 1 kHz ≤ f ≤ 100 kHz, as well as some thermal characterizations, namely the differential scanning calorimetry (DSC) and the differential thermal analysis (DTA) thermograms, were, measured and presented for polycrystalline virgin samples of the titled compound. It is one member of the long-chain of Zn hybrids of the series (n-C_nH_2n+1NH₃)₂ZnCl₄ (n = 8–18) and hence it belongs to the class of thermal energy storage materials.Our data evidenced that the hybrid undergoes a first order solid-solid structural phase transition from an intercalation to a non-intercalation at ≈373 K which is associated with an increase in the interlayer spacing “d” by 19.3%. In the room temperature phase, the hybrid is intercalated and tends to crystallize in an isolated square tetrahedra of zero-dimensional (0D) but arranged in the crystal system in two-dimensional (2D) via the assisted charge hydrogen bonds NH…Cl. It is therefore highly packed and hence have a highly transition temperature, highly thermal energy storage compared with other hybrids of the same n but of different M. These novelties characteristics suggested that the hybrid is more suitable for solar energy research. The even-odd effect, which is only common for Zn and Co in the room temperature phase and absent for other compounds, as well as the mechanism of the phase change have been discussed. The role of the coordination of the divalent metal ion and the dimensionality of the isolated unit (MCl₄)⁻² (M = Zn and/or Co) are considered. Comparison of the current phase transition with that of Zn compounds (n = 8, 10, 12, and 14) has been given.     

Simulation of the spatial distribution of the acoustic pressure in sonochemical reactors with numerical methods: A review

Numerical methods for the calculation of the acoustic field inside sonoreactors have rapidly emerged in the last 15 years. This paper summarizes some of the most important works on this topic presented in the past, along with the diverse numerical works that have been published since then, reviewing the state of the art from a qualitative point of view. In this sense, we illustrate and discuss some of the models recently developed by the scientific community to deal with some of the complex events that take place in a sonochemical reactor such as the vibration of the reactor walls and the nonlinear phenomena inherent to the presence of ultrasonic cavitation. In addition, we point out some of the upcoming challenges that must be addressed in order to develop a reliable tool for the proper designing of efficient sonoreactors and the scale-up of sonochemical processes.     

Hybrid device for acoustic noise reduction and energy harvesting based on a silicon micro-perforated panel structure

A kind of hybrid device for acoustic noise reduction and vibration energy harvesting based on the silicon micro- perforated panel （MPP） resonant structure is investigated in the article. The critical parts of the device include MPP and energy harvesting membranes. They are all fabricated by means of silicon micro-electro-mechanical systems （MEMS） tech- nology. The silicon MPP has dense and accurate micro-holes. This noise reduction structure has the advantages of wide band and higher absorption coefficients. The vibration energy harvesting part is formed by square piezoelectric membranes arranged in rows. ZnO material is used as it has a good compatibility with the fabrication process. The MPP, piezo- electric membranes, and metal bracket are assembled into a hybrid device with multifunctions. The device exhibits good performances of acoustic noise absorption and acoustic-electric conversion. Its maximum open circuit voltage achieves 69.41 mV.     

Nonlinear spectral-like schemes for hybrid schemes

In spectral-like resolution-WENO hybrid schemes,if the switch function takes more grid points as discontinuity points,the WENO scheme is often turned on,and the numerical solutions may be too dissipative.Conversely,if the switch function takes less grid points as discontinuity points,the hybrid schemes usually are found to produce oscillatory solutions or just to be unstable.Even if the switch function takes less grid points as discontinuity points,the final hybrid scheme is inclined to be more stable,provided the spectral-like resolution scheme in the hybrid scheme has moderate shock-capturing capability.Following this idea,we propose nonlinear spectral-like schemes named weighted group velocity control(WGVC)schemes.These schemes show not only high-resolution for short waves but also moderate shock capturing capability.Then a new class of hybrid schemes is designed in which the WGVC scheme is used in smooth regions and the WENO scheme is used to capture discontinuities.These hybrid schemes show good resolution for small-scales structures and fine shock-capturing capabilities while the switch function takes less grid points as discontinuity points.The seven-order WGVC-WENO scheme has also been applied successfully to the direct numerical simulation of oblique shock wave-turbulent boundary layer interaction.     

Enhancing the performance of poly(3-hexylthiophene)/ZnO nanorod arrays based hybrid solar cells through incorporation of a third component

Sparse ZnO nanorod arrays(NRAs)are fabricated on transparent conducting oxide coated glass substrates by using a modified liquid phase epitaxial growth method.By adjusting the polymer concentrations and the spin-coating parameters,full infiltration of poly(3-hexylthiophene)(P3HT)into the as-prepared ZnO NRAs is achieved at 130°C in vacuum.A third component is incorporated into the P3HT/ZnO NRAs ordered bulk heterojunctions(BHJs)either through ZnO surface modification with N719dye or CdS shell layer or by inclusion of a fullerene derivative into the P3HT matrix.Experimental results indicate that performances of the hybrid solar cells are improved greatly with the incorporation of a third component.However,the working principles of these third components differ from one another,according to morphology,structure,optical property,charge transfer and interfacial properties of the composite structures.An ideal device architecture for hybrid solar cells based on P3HT/ZnO NRAs ordered BHJs is proposed,which can be used as a guidance to further increase the power conversion efficiency of such solar cells.     

Microwave‐assistant route to hybrid semiconductor nanocrystals with quasi solution‐solid‐solid mechanism

A facile microwave‐assistant route was developed for the synthesis of hybrid nanocrystals. Colloidal hybrid nanocrystals, Ag₂S‐CdS, were prepared by using Ag₂S nanocrystals and cadmium diethyldithiocarbamate as raw materials under microwave irradiation. The fast ion conductor, Ag₂S nanocrystal, catalyzes the growth of CdS nano‐building blocks through a quasi solution‐solid‐solid mechanism. The ultraviolet‐visible absorption and photoluminescence spectra of the Ag₂S‐CdS hybrid nanocrystals were investigated. One of the main advantages for this synthesis is the efficiency of dramatically reducing overall processing time. This report provides a new route for the growth of semiconductor hybrid nanocrystals based on Ag₂S and may be extended to the preparation of other hybrid colloidal nanostructures.     

Temperature dependence of the light yield of the LAB-based and mesitylene-based liquid scintillators

We studied the temperature dependence of the light yield of linear alkyl benzene(LAB)-based and mesitylene-based liquid scintillators. The light yield increases by 23% for both liquid scintillators when the temperature is lowered from 26 to-40, correcting for the temperature response of the photomultiplier tube. The measurements help to understand the energy response of liquid scintillator detectors. Especially, the next generation reactor neutrino experiments for neutrino mass hierarchy, such as the Jiangmen Underground Neutrino Observatory(JUNO), require very high energy resolution. As no apparent degradation on the liquid scintillator transparency was observed, lowering the operation temperature of the detector to ～4 will increase the photoelectron yield of the detector by 13%, combining the light yield increase of the liquid scintillator and the quantum efficiency increase of the photomultiplier tubes.     

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对新提出的套管结构聚变-快裂变增殖堆包层概念设计方案进行了热工水力学分析和设计,给出了典型的热工设计参数,并结合大型热工水力学软件CFX对其进行了温度场和压力分布的模拟分析。分析结果表明,材料温度均已低于许用温度,冷却剂出口温度高于773K,冷却剂压降也符合工程上的要求,初步验证了增殖堆包层设计的合理性。     

Characterization of an in‐vacuum PILATUS 1M detector

A dedicated in‐vacuum X‐ray detector based on the hybrid pixel PILATUS 1M detector has been installed at the four‐crystal monochromator beamline of the PTB at the electron storage ring BESSY II in Berlin, Germany. Owing to its windowless operation, the detector can be used in the entire photon energy range of the beamline from 10 keV down to 1.75 keV for small‐angle X‐ray scattering (SAXS) experiments and anomalous SAXS at absorption edges of light elements. The radiometric and geometric properties of the detector such as quantum efficiency, pixel pitch and module alignment have been determined with low uncertainties. The first grazing‐incidence SAXS results demonstrate the superior resolution in momentum transfer achievable at low photon energies.