[en] Objective: To investigate imaging diagnosisand differential diagnosis of hemangiopericytoma in the region of jugular foramen. Methods: 1 case of hemangiopericytoma in the region of jugular foramen proved by surgery and pathology was examined by 64 slices multiple rows sprial CT and 1.5T MRI pre-operation, the imaging features were analyzed retrospectively. Results: The hemangiopericytoma in the region of jugular foramen was misdiagnosised by both CT and MRI pre-operation. The tumor was oval in shape, with distinct boundary. Homogeneous and obvious enhancement was seen after giving contrast. Adjacent vessel were pushed by the tumor and deformed Jugular foramen enlarged because of destruction of bone. Conclusion: There isn't specific CT and MRI finding for hemangiopericytoma in the region of jugular foramen. However, imaging examination can clearly display the tumor and adjacent structures, so as to provide accurate anatomy information for surgery. (authors)

[en] Flexible light-emitting diodes (LEDs) are highly desired for wearable devices, flexible displays, robotics, biomedicine, etc. Traditionally, the transfer process of an ultrathin wafer of about 10–30 μm to a flexible substrate is utilized. However, the yield is low, and it is not applicable to thick GaN LED chips with a 100 μm sapphire substrate. In this paper, transferable LED chips utilized the mature LED manufacture technique are developed, which possesses the advantage of high yield. The flexible LED array demonstrates good electrical and optical performance. (paper)

[en] Strontium titanate (SrTiO₃), which is a crucial perovskite oxide with a direct energy band gap of 3.2 eV, holds great promise for ultraviolet (UV) photodetection. However, the response performance of the conventional SrTiO₃-based photodetectors is limited by the large relative dielectric constant of the material, which reduces the internal electric field for electron-hole pair separation to form a current collected by electrodes. Recently, graphene/semiconductor hybrid photodetectors by van-der-Waals heteroepitaxy method demonstrate ultrahigh sensitivity, which is benefit from the interface junction architecture and then prolonged lifetime of photoexcited carriers. Here, a graphene/SrTiO₃ interface-based photodetector is demonstrated with an ultrahigh responsivity of 1.2 × 10⁶ A/W at the wavelength of 325 nm and ∼ 2.4 × 10⁴ A/W at 261 nm. The corresponding response time is in the order of ∼ ms. Compared with graphene/GaN interface junction-based hybrid photodetectors, ∼ 2 orders of magnitude improvement of the ultrahigh responsivity originates from a gain mechanism which correlates with the large work function difference induced long photo-carrier lifetime as well as the low background carrier density. The performance of high responsivity and fast response speed facilitates SrTiO₃ material for further efforts seeking practical applications. (paper)

[en] Gamma-ray (γ-ray) radiation for silicon single photon avalanche diodes (Si SPADs) is evaluated, with total dose of 100 krad(Si) and dose rate of 50 rad(Si)/s by using ⁶⁰Co as the γ-ray radiation source. The breakdown voltage, photocurrent, and gain have no obvious change after the radiation. However, both the leakage current and dark count rate increase by about one order of magnitude above the values before the radiation. Temperature-dependent current–voltage measurement results indicate that the traps caused by radiation function as generation and recombination centers. Both leakage current and dark count rate can be almost recovered after annealing at 200 °C for about 2 hours, which verifies the radiation damage mechanics. (paper)

[en] Broadband and omnidirectional antireflection coating is generally an effective way to improve solar cell efficiency, because the destructive interference between the reflected and incident light can maximize the light transmission into the absorption layer. In this paper, we report the incident quantum efficiency η _in, not incident energy or power, as the evaluation function by the ant colony algorithm optimization method, which is a swarm-based optimization method. Also, SPCTRL2 is proposed to be incorporated for accurate optimization because the solar irradiance on a receiver plane is dependent on position, season, and time. Cities of Quito, Beijing and Moscow are selected for two- and three-layer antireflective coating optimization over λ = [300, 1100] nm and θ = [0°, 90°]. The η _in increases by 0.26%, 1.37% and 4.24% for the above 3 cities, respectively, compared with that calculated by other rigorous optimization algorithms methods, which is further verified by the effect of position and time dependent solar spectrum on the antireflective coating design. (paper)

[en] Highlights: • BNTM ceramics were prepared for the first time by solid-state reaction route. • Crystal structure changes from mixed phases to tetragonal then to cubic phase. • BN6TM meets the Y5V specification, and all of the Mn ions exist as Mn²⁺. • The role of $2N{d}_{Ba}^{·}-M{n}_{Ti}^{″}$ defect complexes was investigated. (Ba_1−xNd_x) (Ti_0.97Mn_0.03)O₃ (BNTM) (x = 0.01, 0.02, 0.04, 0.06) ceramics were prepared using a conventional cold-pressing ceramic technique. The structure, valence state and dielectric properties were investigated using XRD, RS, SEM, TEM, EPR, and dielectric temperature and frequency measurements. XRD, RS analysis coupled with SEM and TEM observations indicate that the samples have a coexistence of tetragonal and hexagonal phase at room temperature as x ≤ 0.02 and become a single phase in the tetragonal as x = 0.04 and in the cubic as x = 0.06 (air-sintered, 1400 °C/12 h). It reveals that Nd³⁺ ions can suppress hexagonal phase effectively and benefit the formation of single-phase ceramics. Improvement of dielectric properties is accompanied by the structural evolution. Particularly a cubic ceramic with x = 0.06, the dielectric-peak temperature is found to shift to room temperature, meeting the EIA Y5V specification with tan δ < 0.04. Up to x = 0.04, the phase transition remains first order. The valence state of Mn ions was analyzed by EPR. It is found that Mn ions transform from high valence (+3 and + 4) to low valence (+2) with the increase of Nd concentration, and all of the Mn ions exist as Mn²⁺ when x = 0.06. The unit cell volume and dielectric-peak temperature of BNTM decrease nonlinearly with increasing x, which can be ascribed to the incorporation of Nd ions and the formation of $2N{d}_{Ba}^{·}-M{n}_{Ti}^{″}$ donor-acceptor defect complexes.

[en] Highlights: • MWCNT/SnIn_4S_8 composites were facilely fabricated via in situ solvothermal method. • MWCNT/SnIn_4S_8 composites exhibited significantly enhanced visible-light activity. • MWCNT/SnIn_4S_8 composites showed remarkable visible light photocatalytic activity. • MWCNT/SnIn_4S_8 composites exhibited excellent photo-stability. • Possible photocatalytic mechanism under visible-light irradiation was proposed. - Abstract: Superior photocatalytic activity could be achieved by multi-walled carbon nanotube (MWCNT) incorporated in the porous assembly of marigold-like SnIn_4S_8 heterostructures synthesized by a flexible in-situ solvothermal method. The as-prepared MWCNT/SnIn_4S_8 composites were well-characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) and UV–vis diffuse reflectance spectroscopy (DRS). The photocatalytic properties of the as-prepared samples were tested by photo-degradation of aqueous malachite green (MG) under the irradiation of visible light. It was found that the MWCNT/SnIn_4S_8 composites showed enhanced visible light photocatalytic activity for dye degradation, and an optimum photocatalytic activity was observed over 3.0 wt.% MWCNT incorporated SnIn_4S_8 composites. The superior photocatalytic activity of MWCNT/SnIn_4S_8 composites could be ascribed to the existence of MWCNT which could serve as a good electron acceptor, mediator as well as the co-catalyst for dye degradation. The synergistic effect between SnIn_4S_8 and MWCNT in the composites facilitated the interfacial charge transfer driven by the excitation of SnIn_4S_8 under visible-light irradiation. Furthermore, a possible mechanism for the photocatalytic degradation of MWCNT/SnIn_4S_8 composites was also discussed