Supernova β^- decay of nuclides ^(53)Fe,^(54)Fe,^(55)Fe and ^(56)Fe in strongly screened plasma

Electron screening has strong effects on electron energy and threshold energy of the beta decay reaction.In this paper,we study β~-decay rates of some iron isotopes.The beta decay rates increase by about two orders of magnitude due to electron screening.Strongly screened beta decay rates due to Q-value correction are more than one order of magnitude higher than those without Q-value correction.

Exploration on Blended Teaching Mode of “Introduction to Software Engineering” Based on SPOC

According to the abstract and practical characteristics of introduction to software engineering,the mixed flipped classroom teaching method is used in the teaching process.It can stimulate students’interest in learning.Taking the SPOC course“Introduction to software engineering”offered by Chongqing University as an example,this study uses the blended flipped classroom teaching method of“learning before teaching”.Online teaching resources design,teaching process design and assessment design were devised and practiced.Through the practice of blended flipped classroom teaching based on SPOC,the students’autonomous learning ability is improved.The effective combination of online teaching and offline classroom is realized.The teaching effect of this course has improved.

Rietveld Refinement of New Solid Solution Al_xSb_ ( 3-x)Y_5 (0≤x≤2.16)

The X-ray diffraction analyses show that the existence of a continuous solid solution of Al_xSb_ 3-xY_5 (0≤x≤216). Al_xSb_ 3-xY_5 crystallizes in the hexagonal system with the space group P6_3/mcm (193) and Mn_5Si_3 structure type. The cell parameters for Al_2SbY_5 compound at 25 ℃ are a=0.88086 (2) nm, c=0.64662 (2) nm.

Strong screening effects on resonant nuclear reaction ^(23)Mg(p,γ) ^(24)Al in the surface of magnetars

Based on the theory of relativistic superstrong magnetic fields （SMFs）, by using the method of Thomas-Fermi-Dirac approximations, we investigate the problem of strong electron screening （SES） in SMFs and the influence of SES on the nuclear reaction of 23Mg （p, Y）24A1. Our calculations show that the nuclear reaction will be markedly effected by the SES in SMFs in the surface of magnetars. Our calculated screening rates can increase two orders of magnitude due to SES in SMFs.

Mid-wavelength nBn photodetector with high operating temperature and low dark current based on InAs/InAsSb superlattice absorber

In this paper,we demonstrate nBn InAs/InAsSb type II superlattice(T2SL)photodetectors with AlAsSb as the barrier that targets mid-wavelength infrared(MWIR)detection.To improve operating temperature and suppress dark current,a specific Sb soaking technique was employed to improve the interface abruptness of the superlattice with device passivation using a SiO_(2) layer.These result in ultralow dark current density of 6.28×10^(-6)A/cm^(2)and 0.31 A/cm^(2)under-600 mV at 97 K and297 K,respectively,which is lower than most reported InAs/InAsSb-based MWIR photodetectors.Corresponding resistance area product values of 3.20×10^(4)Ω·cm^(2)and 1.32Ω·cm^(2)were obtained at 97 K and 297 K.A peak responsivity of 0.39 A/W with a cutoff wavelength around 5.5μm and a peak detectivity of 2.1×10^(9)cm·Hz^(1/2)/W were obtained at a high operating temperature up to 237 K.

Joint iterative compressed sensing algorithm eliminating clipping noise in underwater acoustic communication system

Due to the intricacy characteristics of the Underwater Acoustic（UWA） channel especially the limited bandwidth, Orthogonal Frequency Division Multiplexing（OFDM） is used because of its high spectrum efficiency. However, relatively high Peak-to-Average-Power Ratio（PAPR） limits the efficiency of OFDM in UWA communication, leading to saturation in the power amplifier and consequent distortion of the signal. Clipping and C companding as the most classic and convenient algorithms, are widely applied to address the high PAPR issue. However clipping introduces additional noise which degrades the system＇s performance and traditional C companding is also not suitable for underwater acoustic field. Thus, an improved C companding combined with clipping is proposed here. Due to the sparseness of clipping noise, Compressed Sensing（CS） can be utilized to estimate it. The scheme exploits pilot tones and data tones as observations instead of reserve tones, which is different from the previous works and improves data rate. Furthermore, to minimize the effect of the underwater acoustic channel, the channel is also estimated using the CS technique, which provides more accurate channel characteristics than Least Square（LS） or Minimum Mean Square Error（MMSE） estimation algorithms. The effectiveness of the proposed algorithm is proved in computer simulations as well as in a pool experiment.

Improved Location Algorithm of VIRE Based on RFID

Using linear interpolation method, VIRE algorithm simply treats the signal strength value and distance of the reference tag as a linear relationship, leading to the inaccuracy of signal strength value for virtual reference tags. The threshold in VIRE algorithm is a fixed value that needs repeatedly adjustment through experiments, which results in the complicated algorithm. To solve these problems, an improved algorithm is proposed in this paper, including nonlinear interpolation algorithm, dynamic threshold setting and tag self-correction of fuzzy map, which builds an indoor positioning system based on reference tags. The experimental results show that the improved algorithm can improve the positioning accuracy and improve the stability of positioning results under bad environmental conditions without increasing the number of reference tags.

High-uniformity 2×64 silicon avalanche photodiode arrays with silicon multiple epitaxy technology

In this paper,high-uniformity 2×64 silicon avalanche photodiode[APD]arrays are reported.Silicon multiple epitaxy technology was used,and the high performance APD arrays based on double-layer epiwafers are achieved for the first time,to the best of our knowledge.A high-uniformity breakdown voltage with a fluctuation of smaller than 3.5 V is obtained for the fabricated APD arrays.The dark currents are below 90 pA for all 128 pixels at unity gain voltage.The pixels in the APD arrays show a gain factor of larger than 300 and a peak responsivity of 0.53 A/W@M=1 at 850 nm[corresponding to maximum external quantum efficiency of 81%]at room temperature.Quick optical pulse response time was measured,and a corresponding cutoff frequency up to 100 MHz was obtained.