摘要：Optimization of grain boundary engineering(GBE) process is explored in a Fe–20Cr–19Mn–2Mo–0.82N high-nitrogen and nickel-free austenitic stainless steel, and its intergranular corrosion(IGC) property after GBE treatment is experimentally evaluated. The proportion of low Σ coincidence site lattice(CSL) boundaries reaches 79.4% in the sample processed with 5% cold rolling and annealing at 1423 K for 72 h;there is an increase of 32.1% compared with the solution-treated sample. After grain boundary character distribution optimization, IGC performance is noticeably improved. Only Σ3 boundaries in the special boundaries are resistant to IGC under the experimental condition. The size of grain cluster enlarges with increasing fraction of low ΣCSL boundaries, and the amount of Σ3 boundaries interrupting the random boundary network increases during growth of the clusters, which is the essential reason for the improvement of IGC resistance.

摘要：Photocatalytic technology holds great promise in renewable energy and environmental ***,we report the synthesis of a class of polyaniline-sensitized BiOCI core/shell nanosheets with visible-light photocatalytic activity by a one-step oxidative polymerization method and show how the hybrid nanosheet boosts the photocatalytic activity and stability for degradation of Rhodamine B (RhB).In this unique structure,the ultrathin polyaniline (PANI)as a shell with the thickness of about 1-2nm,can widen the response of the catalyst to visible light to boost photocatalysis and the BiOCI core can promote the separation of photogenerated carriers from the *** demonstrate that the optimized BiOCl/ PANI core/shell photocatalyst shows nearly three times higher photocatalytic activity for the degradation of RhB than pure BLOC1and also shows high *** work provides a new strategy for the design of a highly efficient hybrid photo- catalyst driven by visible light.

摘要：A novel text independent speaker identification system is proposed. In the proposed system, the 12-order perceptual linear predictive cepstrum and their delta coefficients in the span of five frames are extracted from the segmented speech based on the method of pitch synchronous analysis. The Fisher ratios of the original coefficients then be calculated, and the coefficients whose Fisher ratios are bigger are selected to form the 13-dimensional feature vectors of speaker. The Gaussian mixture model is used to model the speakers. The experimental results show that the identification accuracy of the proposed system is obviously better than that of the systems based on other conventional coefficients like the linear predictive cepstral coefficients and the Mel-frequency cepstral coefficients.

摘要：Lightweight and efficient carbon-based microwave absorbents are significant in addressing the increasing severity of electromagnetic *** this study,hierarchical NiO/Ni nanosheets with a tuneable phase and morphology supported on a carbon fiber substrate(CF@NiO/Ni)were fabricated using a hydrothermal approach and post-annealing *** the annealing temperature increases,more metallic Ni is formed,and an apparent porosity appears on the sheet *** from the advantages of a three-dimensional(3D)conducting network,hierarchical porous structure,reinforced dipole/interface polarization,multiple scattering,and good impedance matching,the CF@NiO/Ni-500 composite exhibits an excellent microwave absorption performance even at a filling rate of only 3wt%.Specifically,its minimal reflection loss is-43.92 dB,and the qualified bandwidth is up to 5.64 *** addition,the low radar cross-section area of the CF@NiO/Ni composite coating confirms its strong ability to suppress electromagnetic wave *** expect that this work could contribute to a deeper understanding of the phase and morphology evolution in enhancing microwave absorption.

摘要：Physical unclonable function （PUF） makes use of the uncontrollable process variations during the production of IC to generate a unique signature for each IC. It has a wide application in security such as FPGA intellectual property （IP） protection, key generation and digital rights management. Ring oscillator （RO） PUF and Arbiter PUF are the most popular PUFs, but they are not specially designed for FPGA. RO PUF incurs high resource overhead while obtaining less challenge-response pairs, and requires ＂hard macros＂ to implement on FPGAs. The arbiter PUF brings low resource overhead, but its structure has big bias when it is mapped on FPGAs. Anderson PUF can address these weaknesses of current Arbiter and RO PUFs implemented on FPGAs. However, it cannot be directly implemented on the new generation 28 nm FPGAs. In order to address these problems, this paper designs and implements a delay-based PUF that uses two LUTs in an SLICEM to implement two 16-bit shift registers of the PUF, 2-to-1 multiplexers in the carry chain to implement the multiplexers of the PUF, and any one of the 8 flip-flops to latch 1-bit PUF signatures. The proposed delay-based PUF is completely realized on 28 nm commercial FPGAs, and the experimental results show its high uniqueness, reliability and reconfigurability. Moreover, we test the impact of aging on it, and the results show that the effect of aging on the proposed PUF is insignificant, with only 6% bit-flips. Finally, the prospects of the proposed PUF in the FPGA binding and volatile key generation are discussed.

摘要：An empirical formula for composition demixing analysis in cathodic arc ion plating using alloy target is established based on the concepts of average charged state and relative demixing parameter. The level of composition demixing effect is presented by demixing degree of one element. For binary constituent alloy target, the composition change trend in coating is discussed and the limit of demixing degree for each element is determined. The content of one element with higher average charged state gets larger in coating than in alloy target, at meantime, the content of one element with lower average charged state gets less. For each one of the two constituents, the less the atom percent in alloy target, the larger the difference of its contents between the coating and the target. For triple constituent alloy target, the content change of one element with moderate average charged state is discussed in detail. Its content in coating getting larger or less is determined by the combination result of the contents of the other two elements in alloy target. For a given content of the element with moderate average charged state in triple alloy target, the content deviation level of that element from coating to alloy target will be not larger than that using binary alloy target containing only that element and one of the two others. According to the wanted coating composition, the composition design of alloy target is easily deduced from the formula.

摘要：Broadband sound sink/absorber via a structure with deep sub-wavelength thickness is of great and continuing interest in physics and engineering *** intuitive technique extensively used is to combine components(resonators)with quasi-perfect absorption to piece together a broad absorbing band,but the requirement of quasi-perfect absorption substantially places a very strict restriction on the impedance and thickness of the ***,we theoretically and experimentally demonstrate that a compact broadband acoustic sink that quasi-perfectly absorbs broadband arriving sound waves can be achieved with coherently coupled‘‘weak resonances"(resonant sound absorbing systems with low absorption peaks).Although each component exhibits rather low absorption peak alone,via manipulating the coherent coupling effect among the components,they collectively provide a remarkably improved performance over a wide frequency range with a significantly compressed *** illustrate the design principle,a hybrid metasurface utilizing the coaction of parallel and cascade couplings is presented,which possesses an average absorption coefficient of 0.957 in the quasi-perfect band(a>0:9)from 870 to 3224 Hz with a thickness of only 3.9 *** results open new avenues for the development of novel and highly efficient acoustic absorbers against low frequency noise,and more essentially,suggest an efficient approach towards on-demand acoustic impedance engineering in broadband.

摘要：CoFe_(2)O_(4)has been widely used for electromagnetic wave absorption owing to its high Snoek limit,high anisotropy,and suitable saturation magnetization;however,its inherent shortcomings,including low dielectric loss,high density,and magnetic agglomeration,limit its application as an ideal *** study investigated a microstructure regulation strategy to mitigate the inherent disadvantages of pristine CoFe_(2)O_(4)synthesized via a sol–gel auto-combustion method.A series of CoFe_(2)O_(4)foams(S0.5,S1.0,and S1.5,corresponding to foams with citric acid(CA)-to-Fe(NO_(3))_(3)·9H_(2)O molar ratios of 0.5,1.0,and 1.5,respectively)with two-dimensional(2D)curved surfaces were obtained through the adjustment of CA-to-Fe^(3+)ratio,and the electromagnetic parameters were adjusted through morphology *** to the appropriate impedance matching and conductance loss provided by moderate complex permittivity,the effective absorption bandwidth(EAB)of S0.5 was as high as 7.3 GHz,exceeding those of most CoFe_(2)O_(4)-based ***,the EAB of S1.5 reached 5.0 GHz(8.9–13.9 GHz),covering most of the X band,owing to the intense polarization provided by lattice defects and the heterogeneous *** three-dimensional(3D)foam structure circumvented the high density and magnetic agglomeration issues of CoFe_(2)O_(4)nanoparticles,and the good conductivity of 2D curved surfaces could effectively elevate the complex permittivity to ameliorate the dielectric loss of pure CoFe_(2)O_(4).This study provides a novel idea for the theoretical design and practical production of lightweight and broadband pure ferrites.

摘要：The thermal conduction of suspended few-layer hexagonal boron nitride （h-BN） sheets was experimentally investigated using a noncontact micro-Raman spectroscopy method. The first-order temperature coefficients for monolayer （1L）, bilayer （2L） and nine-layer （9L） h-BN sheets were measured to be -（3.41 ± 0.12）× 10-2, -（3.15 ± 0.14） × 10-2 and -（3.78 ±0.16）× 10-2 cm-1.K-1, respectively. The room-temperature thermal conductivity of few-layer h-BN sheets was found to be in the range from 227 to 280 W.m-1-K-1, which is comparable to that of bulk h-BN, indicating their potential use as important components to solve heat dissipation problems in thermal management configurations.

摘要：The protein-based molecular recognition of the adenine ring is essential to understand protein function and drug design as *** this paper,a variety of the adenine-based inhibitors with modified groups of amino groups,nitrogen and oxygen atoms in the aromatic ring are designed,and the binding capability of these adenosine analogues with an aminoglycoside antibiotic kinase [APH(3')-IIIa] are investigated with activity assays and isothermal titration calorimetry(ITC) experiments.1-aminoisoquinoline is one of the weakest substrates bound to APH(3')-IIIa with the lowest affinity(high ki and high kd) and the smallest negative value of free energy change(G) among the inhibitors *** binding process of adenine and 5-nitroisoquinoline to APH(3')-IIIa is an enthalpy-driven event with unfavorable entropy,which is consistent with the energy change induced by the binding of ATP to the ***,the reverse is true for 1-aminoisoquinoline,3-amino-5-nitrobenzisothiazole,5-aminoisoquinoline binding to the enzyme because the entropy is more favorable and the enthalpy makes a lower contribution to the binding *** results suggest that small changes of the adenine ring can lead to significant influence on the ability of these analogues to occupy the adenine-binding region of the enzyme,which can be the potential inhibitors as drug candidates against the bacterial resistance.