摘要：Based on the thermal network of the two-dimensional heterojunction bipolar transistors(HBTs) array, the thermal resistance matrix is presented, including the self-heating thermal resistance and thermal coupling resistance to describe the self-heating and thermal coupling effects, *** HBT cells along the emitter length direction, the thermal coupling resistance is far smaller than the self-heating thermal resistance, and the peak junction temperature is mainly determined by the self-heating thermal ***, the thermal coupling resistance is in the same order with the self-heating thermal resistance for HBT cells along the emitter width ***, the dependence of the thermal resistance matrix on cell spacing along the emitter length direction and cell spacing along the emitter width direction is also investigated, *** is shown that the moderate increase of cell spacings along the emitter length direction and the emitter width direction could effectively lower the self-heating thermal resistance and thermal coupling resistance,and hence the peak junction temperature is decreased, which sheds light on adopting a two-dimensional non-uniform cell spacing layout to improve the uneven temperature *** taking a 2 × 6 HBTs array for example, a twodimensional non-uniform cell spacing layout is designed, which can effectively lower the peak junction temperature and reduce the non-uniformity of the dissipated *** the HBTs array with optimized layout, the high power-handling capability and thermal dissipation capability are kept when the bias voltage increases.

摘要：Developing microwave absorption(MA)materials with satisfied comprehensive performance is a great challenge for tackling severe electromagnetic *** particular,the magnetic component/carbon hybrids absorbers always suffer from high filler ***,we propose a feasible strategy to construct hierarchical porous carbon with tightly embedded Ni nanoparticles(Ni@NPC).These highly dispersed Ni nanoparticles produce strong magnetic coupling networks to enhance magnetic loss ***,the interconnected hierarchical dielectric carbon network affords favorable dipolar/interfacial polarization,conduction loss,multiple reflection and ***,with an ultralow filler loading of 5 wt.%,the resultant Ni@NPC/paraffin composite achieves an excellent MA performance with a minimum reflection loss of as high as-72.4 dB and a broad absorption bandwidth of 5.0 *** capability outperforms most current magnetic-dielectric hybrids ***,the MA capacity can be easily tuned with adjustments in thickness,content and type of magnetic ***,this work opens up new avenues for the development of high-performance and lightweight MA materials.

摘要：Given the carbon peak and carbon neutrality era,there is an urgent need to develop high-strength steel with remarkable hydrogen embrittlement *** is crucial in enhancing toughness and ensuring the utilization of hydrogen in emerging iron and steel ***,the pursuit of enhanced metallic materials presents a cross-disciplinary scientific and engineering *** high-strength,toughened steel with both enhanced strength and hydrogen embrittlement(HE)resistance holds significant theoretical and practical *** ensures secure hydrogen utilization and further carbon neutrality objectives within the iron and steel *** on the design principles of high-strength steel HE resistance,this review provides a comprehensive overview of research on designing surface HE resistance and employing nanosized precipitates as intragranular hydrogen *** also proposes feasible recommendations and prospects for designing high-strength steel with enhanced HE resistance.

摘要：We compare the transport properties of electrons in monolayer graphene by modulating the Fermi velocity inside the barrier. A critical transmission angle is found only when the Fermi velocity in the barriers is larger than the one outside the barriers. It is shown that the transmission exhibits periodicity with the incident angle below the critical transmission angle, and attenuates exponentially in the opposite situation. For both situations, peak splitting occurs in the transmission as the number of the velocity barriers increases, and the characteristics of the transmission suggest an interesting application of an excellent band-pass filter. The dependence of the conductance on the Fermi energy through an identical velocity- modulation structure differs wildly with different Fermi velocities of the barrier. The counterpart of the peak splitting is the sharp oscillations in the conductance profile. Furthermore, some oscillations for the multiple barriers are so sharp that the structure may be used as an excellent sensor.

摘要：Cough is a defensive behavior that protects the respiratory system from infection and clears airway *** airflow dynamics have been analyzed by a variety of mathematical and experimental *** this paper,the cough airflow dynamics of 42 subjects were obtained and *** identification model based on piecewise Gauss function for cough airflow dynamics is proposed through the dimensionless method,which could achieve over 90%identification ***,an assisted cough system based on pneumatic flow servo system is *** vacuum situation and feedback control are used to increase the simulated peak cough flow rate,which are important for airway secretion clearance and to avoid airway collapse,*** simulated cough peak flow could reach 5 L/s without the external assistance such as manual pressing,patient cooperation and other ***,the backstepping control is developed to generate a simulated cough airflow that closely mimics the natural cough airflow of *** assisted cough system opens up wide opportunities of practical application in airway secretion clearance for critically ill patients with COVID 2019 and other pulmonary diseases.

摘要：CaO–SiO_(2)compounds compromise one of the most common series of oxide particles in liquid steels, which could significantly affect the service performance of the steels as crack initiation sites. However, the structural, electronic, and mechanical properties of the compounds in CaO–SiO_(2)system are still not fully clarified due to the difficulties in the experiments. In this study, a thorough investigation of these properties of CaO–SiO_(2)compound particles in steels was conducted based on first-principles density functional theory. Corresponding phases were determined by thermodynamic calculation, including gamma dicalcium silicate(γ-C2S), alpha-prime(L) dicalcium silicate(αL′-C2S), alpha-prime(H) dicalcium silicate(αH′-C2S), alpha dicalcium silicate(α-C2S), rankinite(C3S2), hatrurite(C3S), wollastonite(CS), and pseudowollastonite(Ps-CS). The results showed that the calculated crystal structures of the eight phases agree well with the experimental results. All the eight phases are stable according to the calculated formation energies, and γ-C2S is the most stable. O atom contributes the most to the reactivity of these phases. The Young’s modulus of the eight phases is in the range of 100.63–132.04 GPa. Poisson’s ratio is in the range of0.249–0.281. This study provided further understanding concerning the CaO–SiO_(2)compound particles in steels and fulfilled the corresponding property database, paving the way for inclusion engineering and design in terms of fracture-resistant steels.

摘要：目的:提出一种震后功能可快速恢复的装配式中柱节点,并建立其设计理论;考察装配式中柱节点的抗震性能及震后修复性能,并提出设计建议。创新点:提出一种可快速恢复震后功能的装配式中柱节点;2.提出装配式中柱节点设计理论,并通过数值手段对其合理性进行校核;3.试验研究考察基础试件的抗震性能及震后修复性能。方法:1.通过理论分析手段建立装配式中柱节点设计理论;2.利用数值模拟手段通过4组8个算例来验证节点设计理论,并对节点抗震性能进行数值研究;3.对基础试件进行低周往复荷载试验研究及修复试验研究,进一步验证设计理论的合理性,并考察节点的抗震性能及震后修复性能。结论:1.提出的设计理论可准确地预测装配式中柱节点的屈服荷载;2.设计合理的装配式中柱节点具有良好的承载性能及滞回特性,可满足结构震后功能修复要求;3.翼缘连接盖板厚度和材性、中间螺栓间距和梁段间隙参数对节点抗震性能影响较大,需合理设置。

摘要：In software-defined networking,the separation of control plane from forwarding plane introduces new challenges to network *** paper proposes a fault-tolerant routing mechanism to improve survivability by converting the survivability problem into two sub-problems:constructing an elastic-aware routing tree and controller *** on the shortest path tree,this scheme continuously attempts to prune the routing tree to enhance network *** a certain number of iterations,elastic-aware routing continues to improve network resiliency by increasing the number of edges in this *** results demonstrate this fault-tolerant mechanism performs better than the traditional method in terms of the number of protected nodes and network fragility indicator.

摘要：In this study, seven pinned double-rectangular tube assembled buckling-restrained brace （DRT-ABRB） specimens were experimentally charaeterised by means of an axial cyclic test. The core member of the specimens was a single flat-plate. Two rectangular tubes were assembled using high strength bolts to form an external restraining member. Each rectangular tube was composed of an external steel channel and a cover plate. A gap or thin rubber filler was set between the core and the external restraining member to form an unbonded layer. The influence of several design parameters on the failure mode and energy dissipation capacity of the ABRB was investigated, including the height of the core wing plate, thickness of the external cover plate, and height of the external channel flange. This experimental study demonstrated that a local pressure-bearing failure at the end of the external member arises when the external cover plate is too thin or if the end construction detail is unreasonable. When the end rotations of the DRT-ABRB were restricted, the hysteretic performance was shown to be superior to that of a pure pinned DRT-ABRB. Finally, all the tested DRT-ABRBs exhibited excellent energy dissipation performance which amply satisfied existing regulation requirements.

摘要：目的:在实际工程服役过程中,纤维增强塑料(FRP)约束混凝土柱在遭遇极限荷载前往往已经经历了长时间的轴压荷载作用。因此,相比其短期力学性能,本文旨在研究FPR约束混凝土柱在长期荷载作用后的力学性能。创新点:1.考虑长期轴压荷载作用,提出一种轴压作用下圆形截面FRP约束混凝土柱的长期变形分析模型;2.提出了长期轴压作用后的FRP约束混凝土本构模型,从本构关系的角度描述两个方面的影响机理。方法:运用混凝土和FRP徐变的长期变形分析迭代计算方法(图3)。结论:1.提出的长期变形分析模型实现了对FRP约束混凝土柱任意目标时刻的应力和应变状态的高效、准确预测;2.将提出的本构模型嵌入有限元软件中,有效地实现对长期轴压作用的考虑;3.基于Open Sees有限元软件,验证了长期变形分析模型和本构模型的有效性和准确性。