Radiation Damage Analysis of Individual Subcells for GaInP/GaAs/Ge Solar Cells Using Photoluminescence Measurements

The radiation damage of three individual subcells for GalnP/GaAs//Ge triple-junction solar cells irradiated with electrons and protons is investigated using photoluminescence （PL） measurements. The PL spectra of each subcell are obtained using different excitation lasers. The PL intensity has a fast degradation after irradiation, and decreases as the displacement damage dose increases. Furthermore, the normalized PL intensity varying with the displacement damage dose is analyzed in detail, and then the lifetime damage coefficients of the recombination centers for GaInP top-cell, GaAs mid-cell and Ge bottom-cell of the triple-junction solar cells are determined from the PL radiative efficiency.

Unified Analysis for Calculating the Incoherent Spontaneous Emission of Cooperative Radiations

A unified analysis is presented to calculate the incoherent spontaneous power of cooperative radiations based on self-amplified spontaneous emission. Using quantum mechanical tools, we derive analytical expressions for the incoherent spontaneous power of undulator and Cherenkov free-electron lasers （FELs）. The undulator and Cherenkov FELs are considered as two different examples for the radiation that accumulate cooperatively. In the case of the undulator FEL, we show an excellent agreement between an expression for the incoherent radiation power derived in the present work and that obtained using a completely different approach [Phys. Ftev. E 65 （2002） 026501]. For the Cherenkov radiation, we demonstrate a satisfactory agreement between the incoherent power predicted in our analysis and previous experimental results.

The influence of thermal radiation on MHD station-point flow past a stretching sheet with heat generation

This letter is concerned with the plane and axisymmetric stagnation-point flows and heat transfer of an electrically-conducting fluid past a stretching sheet in the presence of the thermal radiation and heat generation or absorption. The analytical solutions for the velocity distribution and dimensionless temperature profiles are obtained for the various values of the ratio of free stream velocity and stretching velocity, heat source parameter, Prandtl number, thermal radiation parameter, the suction and injection velocity parameter and magnetic parameter and dimensionality index in the series form with the help of homotopy analysis method （HAM）. Convergence of the series is explicitly dis- cussed. In addition, shear stress and heat flux at the surface are calculated.

DeepRadiation:An intelligent augmented reality platform for predicting urban energy performance just through 360 panoramic streetscape images utilizing various deep learning models

Urban energy simulation is critical for understanding and managing energy performance in cities.In this research,we design a novel framework called DeepRadiation,to enable automatic urban environmental performance prediction.By incorporating deep learning strategies,DeepRadiation predicts solar radiation on an urban scale using just panoramic streetscape images without any 3D modeling and simulation.New York City was chosen as the case study for this research.DeepRadiation is comprised of three different deep learning models organized into two stages.The first stage,named DeepRadiation modeling,serves as the framework's brain.At this stage,solar radiation analysis was performed using a Pix2Pix model,a type of conditional generative adversarial networks(GANs).After extracting GIS data and performing energy simulation analysis to prepare the dataset,the Pix2Pix model was trained on 10000 paired panoramic depth images of streetscapes with only building blocks and related panoramic images of streetscapes with only solar radiation analysis.Two GAN generator evaluation measures named qualitative evaluation and quantitative evaluation were used to validate the trained Pix2Pix model.Both demonstrated high levels of accuracy(qualitative evaluation:93%,quantitative evaluation:89%).DeepRadiation application as the DeepRadiation's sescond stage is the framework's eyes.At this stage,two convolutional neural network(CNN)models(DeepLabv3 and MiDaS)were used to perform computer vision tasks on panoramic streetscape images,such as semantic segmentation and depth estimation.The DeepRadiation application stage allows urban designers,architects,and urban policymakers to use the DeepRadiation framework and experience the final output via augmented reality.

Compositional Distribution and Growth Mode of Garnet Porphyroblasts during Deformation and Metamorphism

Although porphyroblast microstructures play an important role in structural and metamorphic studies, there are still controversies in the interpretation. The focus is how porphyroblasts grow during deformation and metamorphism. In this paper, we introduce a new approach, the Synchrotron Radiation X-Ray Fluorescence, to a hemi-quantitative interpretation of the growth mode of porphyroblasts. The analysis was done at the Beijing Synchrotron Radiation Facility. The specimens were sampled from metapelite of the Baoyintu Group, northern Urad Middle Banner, Inner Mongolia. The new method is successful for determining the microscopic distribution of trace elements in porphybroblasts. The results support the theory of deformation partition, which has been brought forth by Bell and his colleagues, and demonstrate the existence of porphyroblast growth phases and the growth mode of porphyroblasts by hemi-quantitative mineral chemical analysis. The porphyroblast grows stage by stage in the manner of the distribution of a roseleaf and is controlled by deformation. We call the growth stage of porphyroblast a growth phase.

Wavelet Cleaning of Solar Dynamic Radio Spectrograms

By applying the state-of-the-art mathematical apparatus, the wavelet transformation, we explore the possibility of a dynamic cleaning of raw data ob- tained with the Chinese solar radio spectrographs over a wide wavelength range (from 0.7 to 7.6 GHz). We consider the problem of eliminating the interference caused by combination rates of data sampling (10-20 ins), and the low-frequency interference (4-30 s) caused by the receiving equipment changing its characteristics with time. It is shown that the best choice to reconstruct a signal suffering from amplitude, frequency and phase instabilities, is by means of wavelet transformation at both high and low frequencies. We analysed observational data which contained interferences of nonsolar origin such as instrumental effects and other man-made signals. A subsequent comparison of the reference data obtained with the acousto- optical receiver of the Siberian Solar Radio Telescope (SSRT) with the 'cleaned' spectra confirms the correctness of this approach.

Time-domain analysis for vibration and sound radiation of submerged spherical shell excited by force

The vibration and sound radiation of a submerged spherical shell are studied in the time-domain by Laplace transform method, where a CW pulse force acts at the apex of the shell. The numerical results for the case of long pulse show that the different vibrational modes and the resonant or beat radiated sound are excited for different carrier-frequencies, but litle sound is radiated for some vibrational modes. For the case of short pulse the waveforms of the pulse become widened and deformed, when the pulse propagates between apexes of the shell. Then, the Doubly Asymptotic Approximations (DAA2) and Kirchhoff's Retarded Potential Formulate (KRPF)are used to solve the same problem. It is shown that the results of DAA2 and KRPF method have a good agreement with the results of Laplace transform method.

A solar radio dynamic spectrograph with flexible temporal-spectral resolution

Observation and research on solar radio emission have unique scientific values in solar and space physics and related space weather forecasting applications, since the observed spectral structures may carry important information about energetic electrons and underlying physical mechanisms. In this study, we present the design of a novel dynamic spectrograph that has been installed at the Chashan Solar Radio Observatory operated by the Laboratory for Radio Technologies, Institute of Space Sciences at Shandong University. The spectrograph is characterized by real-time storage of digitized radio intensity data in the time domain and its capability to perform off-line spectral analysis of the radio spectra. The analog signals received via antennas and amplified with a low-noise amplifier are converted into digital data at a speed reaching up to 32 k data points per millisecond. The digital data are then saved into a high- speed electronic disk for further off-line spectral analysis. Using different word lengths （1-32k） and time cadences （5 ms-10 s） for off-line fast Fourier transform analysis, we can obtain the dynamic spectrum of a radio burst with different （user-defined） temporal （5 ms-10 s） and spectral （3 kHz-320kHz） resolutions. This enables great flexibility and convenience in data analysis of solar radio bursts, especially when some specific fine spectral structures are under study.

Local-linear-prediction analysis for underwater acoustic target radiated noise

Local-linear-prediction in phase space is performed for the underwater acoustic target radiated noise. Relation curve of average prediction error versus neighboring points' number is calculated. The result is used in judging the nonlinearity of radiated noise time series, and obtaining the appropriate form and coefficients of predicting model. The line and continuous spectral component are predicted respectively. Choice of some model parameters minimizing the prediction error is also discussed.