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Rationale and Objectives To explore the imaging features of whole uterus volume CT perfusion (vCTP) and the influence factors of blood supply in cervical squamous carcinoma (CSC). Materials and Methods vCTP was performed on a 640-slice computed tomography system in 43 patients with CSC diagnosed by biopsy, and 24 cases of them underwent magnetic resonance imaging. The size of the tumor was measured on vCTP and magnetic resonance (MR) images. Perfusion parameters, including arterial blood flow (AF), blood volume, and permeability surface (PS), were measured by two radiologists, using interclass correlation coefficient to evaluate the interobserver reliability. The difference of tumor size and perfusion data was analyzed by paired t test and rank sum test. The correlation of perfusion parameters with some factors was analyzed by Pearson or Spearman correlation analysis. Results Tumor sizes were not significantly different between vCTP and MR images. The interclass correlation coefficient of each parameter was 0.818–0.945. The AF value of CSC was significantly higher than normal uterine body, and the blood volume and PS values of CSC were not statistically different compared with those of normal uterine body. There was no significant difference in AF value of CSC among different FIGO stages and pathological grades. The AF and PS values of CSC were negatively correlated with the age of the patients. Conclusion The vCTP could accurately shows the size of the CSC with use of MR as the reference standard, and its perfusion parameters have good measurement stability; the CSC was hypervascular, but this trend was less pronounced in older women.

This paper proposes an improved cumulant method for probabilistic load flow calculation. The proposed method combined cumulant method and K-means clustering technique. Firstly, the output power of wind farms is divided into several clusters by K-means technique. Then, the conventional cumulant method is performed in each cluster to obtain the probability distributions of output random variables. Finally, the probabilistic load flow results are obtained by integrating probability distributions of output random variables and corresponding weight of each cluster. The performance of the proposed method is evaluated on a modified IEEE 30-bus system. The simulation results demonstrate that the proposed method could yield accurate results with a low computational burden, and it also overcomes the limitation of existing series expansion methods to approximate multimodal probability distributions.

Femtosecond laser treatment has been widely used for modulating different kinds of materials as a convenient and efficient approach. In the process of laser modulation, the ionization caused by femtosecond laser irradiation may significantly affect the propagation and energy deposition of laser pulse inside the material, and thus finally influencing the surface morphology and optimizing the material properties. In this work, the ablation of WS2 is conducted in a wide range of laser fluence by single pulse. With the increase of injected energy, the expansion of craters goes through a process from rapid growth to stabilization both in the direction of diameter and in the depth direction. And a plasma model is proposed to track the dynamic response of the excited material and the transfer and deposition of the laser energy in the irradiation of WS2. The calculated results reveal that a great number of free electrons will generate after the incidence of laser pulse and leads the dense plasma zone to form. In this zone, the reflection on the surface and the absorption inside of WS2 are both enhanced due to the rapid increase of free electron density, which affects the injection and deposition of laser energy, thus resulting in the deposition of most energy in the shallow area below the surface. With the increasing of the laser fluence, the majority of laser energy is deposited on the surface of WS2, which leads the ablation crater to reach the saturation state. Meanwhile, a double-pulse train generated by temporal shaping is utilized to modulate the diameter of craters. By adjusting the pulse delay, the smallest diameter of the crater can be obtained at 0.7 ps. The results pave the way for potential applications of the effective method in controlling the material removal and improving the catalytic performance of pristine WS2.

Based on the defective NR-PC flat lens incorporating Al or Cu, the effects on the resolution for target detection and imaging are studied with dynamic scanning scheme. We use the finite-difference-time-domain method to do this research. Firstly, by using the NR-PC flat lens may improve the refocusing resolution by four times, if compared to the directly backscattered lightwave without using the NR-PC lens. Then, incorporating Al or Cu into the NR-PC flat lens, we find that the dope modes with very high quality factors will occur in the photonic forbidden band. Also the stimulated radiation is enhanced for the character of energy localization of defective photonic crystal. Further studies show that different kinds of metal and structures will result in different dopped modes in the photonic forbidden band, which will lead to the change of the corresponding resolution. Due to the displacement field redistribution, the photonic crystal containing metal ingredients may take on the typical qualities of all-directional reflection, and the resonant tunneling effect may effectively reduce the loss, which provides greatly improvement on the refocusing resolution when using the defective NR-PC flat lens. In conclusion, our investigation provided the basis for converting an idealized LHM lens into a physically realizable NR-PC flat lens. Meanwhile, by impregnating metallic defect into the NR-PC lens, a new method is found out for the improvement of the refocusing resolution, which further optimizes the performance of a detecting and imaging system.

Wurtzite CdS nanoribbons are prepared by using a simple thermal evaporation method. Electron microscopy shows that the ribbons are smooth in surface and uniform in size. Besides the intrinsic emission, the photoluminescence spectrum of a CdS nanoribbon shows a peak at about 580 nm, which may arise from the defect- and the trap- related transitions. The photoresponse of single CdS nanoribbons is researched. When these nanoribbons are exposed to a laser with a wavelength of 400 nm, their conductivity is enhanced greatly. The conductivity of CdS nanoribbons cannot be restored to a value without any illumination even at 5 minutes after the illumination. A model is proposed to explain this phenomenon, which may be due to a slow photoresponse induced by the trap.

A wide wavelength tuning range swept external-cavity laser using an InAs/GaAs quantum-dot superluminescent diode as a gain device is demonstrated. The tunable filter consists of a polygon scanner and a grating in Littrow telescope-less configuration. The swept laser generates greater than 54-mW peak output power and up to 33-kHz sweep rate with a sweep range of 150 nm centered at 1155 nm. The effects of injection current and sweep rate on the sweep performance of the swept laser are studied.

n-ZnO/p-GaN heterojunction light-emitting diodes with and without a Ga2O3 interlayer are fabricated. The electroluminescence (EL) spectrum of the n-ZnO/p-GaN displays a single blue emission at 430 nm originating from GaN, while the n-ZnO/Ga2O3/p-GaN exhibits a broad emission peak from ultraviolet to visible. The broadened EL spectra of n-ZnO/Ga2O3/p-GaN are probably ascribed to the radiative recombination in both the p-GaN and n-ZnO, due to the larger electron barrier (ΔEC = 1.85 eV) at n-ZnO/Ga2O3 interface and the much smaller hole barrier (ΔEV = 0.20 eV) at Ga2O3/p-GaN interface.

National Natural Science Foundation of China [61274072, 60976057, 60876086]; Open Fund of Key Laboratory of Semiconductor Materials Science of Institute of Semiconductors, Chinese Academy of Sciences [KLSMS-1105]

A mode-locked external-cavity laser emitting at 1.17-μm wavelength using an InAs/GaAs quantum-dot gain medium and a discrete semiconductor saturable absorber mirror is demonstrated. By changing the external-cavity length, repetition rates of 854, 912, and 969 MHz are achieved respectively. The narrowest −3-dB radio-frequency linewidth obtained is 38 kHz, indicating that the laser is under stable mode-locking operation.

The optical performance of a grating-coupled external cavity laser based on InAs/InP quantum dots is investigated. Continuous tuning from 1391 nm to 1468 nm is realized at an injection current of 1900 mA. With the injection current increasing to 2300 mA, the tuning is blue shifted to some extent to the range from 1383 nm to 1461 nm. By combining the effect of the injection current with the grating tuning, the total tuning bandwidth of the external cavity quantum-dot laser can reach up to 85 nm. The dependence of the threshold current on the tuning wavelength is also presented.

Longitudinally polarized subwavelength beams have found many applications such as particle acceleration, single molecule dipole detection, second harmonic generation imaging, longitudinally polarization confocal microscopy. We present a radially modulated Bessel-Gaussian beam model which produces longitudinally polarized beams with high purity after being focused by high numerical aperture objective. Based on the vector diffraction theory, the electric field intensity distribution, magnetic field intensity distribution and energy flux density near the focal plane are numerically simulated. The result shows that the full-width at half-maximum is as small as 0.4λ. The method does not require a physical annulus or annular phase filter and it features high energy efficiency, high resolution, thus improving application performances.

Refractive indices and extinction coefficients of 0.92Pb(Mg1/3Nb2/3)O3-0.08PbTiO3 (PMN-0.08PT) single crystal are investigated by variable angle spectroscopic ellipsometry (VASE) at different wavelengths. The parameters relative to the energy band structure are obtained by fitting to the single-oscillator dispersion equation, and the band gap energy is also deduced from the Tauc equation. Similar to most oxygen-octahedra ferroelectrics, PMN-0.08PT has the same dispersion behavior described by the refractive-index dispersion parameters.

Scanning near-field microscopy (SNOM) was used to investigate the low-dimensional semiconductor fluorescence divices, which can work as micro-nano-light source, nano-optical waveguide and light enhancement component in nano-integrated optical circuit. It was found that the quality of semiconductor wire end emission was mainly determined by the sample radius. By designing the wire radius and topography reasonably, it can be used as the light source and optical waveguide in nano-integrated optical circuit. ZnO tetrapod, comb, and CdS multi-branch nano-ribbon also presented quite good adequacy for optical waveguide application, which can function well in light division, congregation, coupling and filtering. 2-D photonic crystal can enhance the light intensity of GaN based LED by as large as 5.2 times. About 30% fluorescence is confined to the surface of photonic crystal. This conclusion is helpful for the optimization of LED light emission. When the resonance excitation condition is fulfilled, Surface plasmm polaritons (SPP) will be excited at the interface between the semiconductor and the silver thin film, which will bring about strong enhancement of electromagnetic field at the interface. Photonic crystal and SPP can realize light enhancement under low_dimensional and nano-scale conditions. The experimental results show that both of them have the potential application as enhancement components in nano-integrated optical circuit.