[en] Measuring deformation of vibrating specimens whose dimensions are in the submillimeter range introduces a number of difficulties using laser interferometry. Normal interferometry is not suitable because of a phase ambiguity problem. In addition, the noise effect is much more serious in the measurement of small objects because a high-magnification lens is used. We present a method for full-field measurement of displacement, velocity, and acceleration of a vibrating miniature object based on image-plane digital holographic microscopy. A miniature cantilever beam is excited by a piezoelectric transducer stage with a sinusoidal configuration. A sequence of digital holograms is captured using a high-speed digital holographic microscope. Windowed Fourier analysis is applied in the spatial and spatiotemporal domains to extract the displacement, velocity and acceleration. The result shows that a combination of image-plane digital holographic microscopy and windowed Fourier analyses can be used to study vibration without encountering a phase ambiguity problem, and one can obtain instantaneous kinematic parameters on each point

[en] Highlights: • The effect of cooling method after intercritical heat treatment on microstructure evolution was investigated. • Fracture mechanism of tensile and impact after different intercritical heat treatment has been analyzed. • The crack initiation and propagation after different intercritical heat treatment was compared in details. - Abstract: The effect of cooling method after intercritical heat treatment on the microstructures and mechanical properties of as-cast steel produced by electroslag casting was investigated. The microstructure characteristics were analyzed by optical microscope (OM), scanning electron microscope (SEM), transmission electron microscopy (TEM) and electron back scatter diffraction (EBSD). The mechanical performance was evaluated by tensile testing at ambient temperature and Charp V-notch impact tests at various temperatures (−40 °C, −20 °C, 20 °C). The tensile and impact fracture micromechanisms were discussed in details. The results of microstructure investigation indicated that water cooling after intercritical heat treatment led to a mixed microstructure of ferrite and tempered martensite, while a composite microstructure of ferrite and tempered bainite was obtained after air cooling. The carbides of Cr, Mo and Nb in matrix after water quenching were finer than the ones after air cooling. Compared with water cooling, a good balance of strength and toughness was obtained after air cooling. The crack propagation path in the steel after water cooling can propagate along the long axis direction of ferrite bands, directly across the intersecting banded ferrite and martensite as well as along the interfaces between ferrite and martensite. However, the crack propagation path in the steel after air cooling depends on the shape, size and distribution of M/A islands

[en] Highlights: • A CMRT method for coherent energy transfer in molecular aggregates was developed. • Applicability of the method was verified in two-site systems with various parameters. • CMRT accurately describes population dynamics in the FMO-complex. • The method is accurate in a large parameter space and computationally efficient. - Abstract: Excitation energy transfer (EET) is crucial in photosynthetic light harvesting, and quantum coherence has been recently proven to be a ubiquitous phenomenon in photosynthetic EET. In this work, we derive a coherent modified Redfield theory (CMRT) that generalizes the modified Redfield theory to treat coherence dynamics. We apply the CMRT method to simulate the EET in a dimer system and compare the results with those obtained from numerically exact path integral calculations. The comparison shows that CMRT provides excellent computational efficiency and accuracy within a large EET parameter space. Furthermore, we simulate the EET dynamics in the FMO complex at 77 K using CMRT. The results show pronounced non-Markovian effects and long-lasting coherences in the ultrafast EET, in excellent agreement with calculations using the hierarchy equation of motion approach. In summary, we have successfully developed a simple yet powerful framework for coherent EET dynamics in photosynthetic systems and organic materials

[en] Aqueous corrosion behavior of YBa₂Cu₃O_7-x superconductor was studied in 1 M H₂SO₄ and 0.1 N NaCl solutions by the potentiodynamic polarization technique. The corrosion rate was found to be higher in 1 M H₂SO₄ than in 0.1 N NaCl solutions. In comparison to pure Cu, YBa₂Cu₃O_7-x is more stable in these solutions. 3 refs

[en] Highlights: •Boron was doped into Bi₂WO₆ using hydrothermal method. •Doping with boron enhanced the photoactivity of Bi₂WO₆ to rhodamine B under simulated solar light. •The catalyst doped with 0.5% boron atoms displayed the highest catalytic activity. •Boron atoms could act as electron traps to separate the electron–hole pairs. -- Abstract: Bi₂WO₆ doped with different amounts of boron atoms (0.1, 0.5, 1.0, 5.0 and 10% B) were synthesized using hydrothermal method and their photocatalytic activities to degrade rhodamine B (RhB) under simulated solar light was investigated. The successful incorporation of B atoms in Bi₂WO₆ was proved by FT-IR, Raman spectra and XPS. Doping with B could affect the pore structure and volume. 0.5% B/Bi₂WO₆ displayed more mesopores with higher total pore volume than pure Bi₂WO₆; while the pores of 10% B/Bi₂WO₆ mainly distributed in microporous range with much less total pore volume. As a result, 0.5% B/Bi₂WO₆ displayed stronger adsorption capacity to RhB, favoring the photodegradation. In addition, the doped B atoms could act as electron traps and facilitate the separation of photogenerated electron–hole pairs due to its electron deficient and oxytropic characteristics. 0.5% B/Bi₂WO₆ displayed the highest photocatalytic activity under simulated solar light with rate constant (k_obs) 8.8 times of that using pure Bi₂WO₆. Its photoactivity was affected by solution pH and the optimum was achieved at pH 7. At this condition, around 100% of RhB (10⁻⁵ mol/L) was degraded in 180 min. The photogenerated holes were the main active species responsible for the photodegradation of RhB by B/Bi₂WO₆

[en] A method has been investigated for highspeed and efficient recovery of palladium from reprocessing waste of spent nuclear fuel by mixing the matrix feedstock with a small amount of KI and an appropriate inert solvent (such as kerosene) as collecting agent. Equilibrium of the reaction can be obtained in less than 30 sec. Percent recovery of palladium is more than 97%. Decontamination coefficient is high. No loss of effectiveness of the system was observed below 1X10⁶ rad of irradiation. (author) 6 refs.; 1 fig.; 4 tabs

[en] The local spin density approximation (LSDA) with the Hubbard model correction is adopted to describe the electronic structures of O-codoped Er-Si systems. The electrons in the 4f orbitals of Er atoms are taken as localized electrons in the framework of an all-electron treatment. The total density of states (DOS) and the partial densities of states for Si(3s, 3p), Er(4f), Er(5d), Er(6s), O(2s), and O(2p) in this ErSiO system are calculated. It is found that the inclusion of the Hubbard U greatly influences the partial DOS of the Er 4f electrons. The separation between the spin-up and the spin-down states of the highly localized 4f orbitals is larger than that of the LSDA results obtained without considering the Hubbard U-parameter. The calculation results provide possible explanations of the experimentally observed erbium-induced impurity energy levels in Si detected by deep-level transient spectroscopy

[en] Flower-like manganese-cobalt (Mn-Co) oxysulfide supported on Ni foam substrate is synthesized by two-step hydrothermal method as binder-free faradaic electrode for charge storage. The crystalline phase and morphology of as-fabricated materials are well-characterized by X-ray diffraction (XRD), Scan electron microscope (SEM), and X-ray photoelectron spectrum (XPS). The results demonstrate that the Mn-Co oxysulfide exists as polycrystal and sulfide are successfully partially substituted into Mn-Co oxide. Impressively, the Mn-Co oxysulfide electrode exhibits excellent electrochemical performance with an ultrahigh specific capacity of 490 C g⁻¹ at 2 A g⁻¹ and 415 C g⁻¹ at 20 A g⁻¹ which is much higher than 301 C g⁻¹ at 2 A g⁻¹ and 174 C g⁻¹ at 20 A g⁻¹of the Mn-Co oxide nanosheets electrode. Moreover, the flower-like Mn-Co oxysulfide electrode also reveals good cycling stability with 86.5% capacity retention at high current density of 20 A g⁻¹ after 3000 cycles. Because of the flower-like structure and partial substitution by sulfide, which provides large reaction surface area and more flexible structure, Mn-Co oxysufide electrode with excellent electrochemical performances would have great prospect for energy storage device applications.

[en] The optical properties of InGaAs/GaAs quantum dots (QDs) were investigated by temperature dependent photoluminescence (PL) and photoreflectance (PR) spectroscopies. The surface morphology and structure analysis of InGaAs QDs were also examined and characterized by a field emission scanning electron microscope (SEM) and an atomic force microscope (AFM). The In_0.5Ga_0.5As/GaAs self-assembled QDs specimens were grown with gas-source molecular beam epitaxy and migration enhanced techniques. The area density of the QDs is on an order of magnitude about 1 x 10¹⁰ dots/cm². The measured PL results exhibited 5 major energy peaks, two of which are attributed to InGaAs QDs, one is attributed to the InGaAs wetting layer and the other two are attributed to GaAs band-gap transitions. Two of the low energy features are identified to the optical transitions of the ground state. They were originated from the two kinds of InGaAs QDs which might be formed with slight change of the indium composition. An inverted ' S curve' shape of the temperature dependent PL peak energies was observed. This abnormal behavior of the line-shape is attributed to carrier localization. The results of PR measurement which reveal energy features on the high energy side contributed by GaAs is also reported

[en] Highlights: • A three-zone transport model for activated corrosion products analysis of Tokamak Cooling Water System was developed. • The model was used in the ACPs evaluation code CATE, giving CATE the capability to calculate spatial distribution of ACPs. • Under normal operation, the major contributors to radioactivity came from the short-life ACPs, especially Mn-56. - Abstract: In the Tokamak Cooling Water System (TCWS), the activated corrosion products (ACPs) play as an important radioactive source, which have impact on reactor inspection and maintenance. A three-zone transport model of ACPs was elaborated in this paper, which is based on the theory that the main driving force for ACPs transport is the temperature change of the coolant throughout the loop and the resulting change in metal ion solubility in the coolant. The three-zone transport model was used to replace the loop-homogenization model in the ACPs evaluation code CATE 1.0, developing CATE to give the capability to calculate spatial distribution of ACPs. As a result, CATE was upgraded to version 2.0. For code testing, a FW/BLK cooling loop of ITER was simulated using CATE 2.0, and the composition and radioactivity of ACPs were calculated. The results showed that the major contributors came from the short-life nuclides, especially Mn-56, which can influence material choice in reactor design and shutdown time before reactor maintenance.