摘要：The development of anode materials with high rate capability and long charge-discharge plateau is the key to improve per-formance of lithium-ion capacitors(LICs).Herein,the porous graphitic carbon(PGC-1300)derived from a new triply interpenetrated co-balt metal-organic framework(Co-MOF)was prepared through the facile and robust carbonization at 1300°C and washing by HCl *** as-prepared PGC-1300 featured an optimized graphitization degree and porous framework,which not only contributes to high plateau capacity(105.0 mAh·g^(−1)below 0.2 V at 0.05 A·g^(−1)),but also supplies more convenient pathways for ions and increases the rate capability(128.5 mAh·g^(−1)at 3.2 A·g^(−1)).According to the kinetics analyses,it can be found that diffusion regulated surface induced capa-citive process and Li-ions intercalation process are coexisted for lithium-ion ***,LIC PGC-1300//AC constructed with pre-lithiated PGC-1300 anode and activated carbon(AC)cathode exhibited an increased energy density of 102.8 Wh·kg^(−1),a power dens-ity of 6017.1 W·kg^(−1),together with the excellent cyclic stability(91.6%retention after 10000 cycles at 1.0 A·g^(−1)).

摘要：Solid oxide fuel cells(SOFCs)have attracted a great deal of interest because they have the highest efficiency without using any noble metal as catalysts among all the fuel cell ***,traditional SOFCs suffer from having a higher volume,current leakage,complex connections,and difficulty in gas *** solve these problems,Rolls-Royce has fabricated a simple design by stacking cells in series on an insulating porous support,resulting in the tubular segmented-in-series solid oxide fuel cells(SIS-SOFCs),which achieved higher output *** work systematically reviews recent advances in the structures,preparation methods,perform-ances,and stability of tubular SIS-SOFCs in experimental and numerical ***,the challenges and future development of tubular SIS-SOFCs are also *** findings of this work can help guide the direction and inspire innovation of future development in this field.

摘要：For a single cylinder engine, the total unbalanced inertial forces occur in the engine block, which results in engine’s vibration and deteriorated noise. In order to eliminate the unbalanced forces, counterweight and primary balance shaft should be attached to the cylinder block so that engine durability and ride comfortability may be further improved. Traditionally one third of connecting rod assembly’s mass is treated as reciprocating mass, and two thirds as rotating mass when designing balance mechanism. In this paper, a new method based on the multibody dynamics simulation is introduced to separate the reciprocating mass and rotating mass of connecting rod assembly. The model consists of crankshaft, connecting rod, piston and the simulation is performed subsequently. According to the simulation results of the main bearing loads, the reciprocating mass and rotating mass are separated. Finally a new balance mechanism is designed and simulation results show that it completely balances inertial forces to improve the engine’s noise vibration and harshness performance.

摘要：This paper presented a novel electrohydrodynamic (EHD) micropump based on MEMS technology. The working mechanisms and classification of EHD micropump were introduced. The fabrication process of EHD micropump was presented with the material selection,optimal design of microelectrode and assembly process. Static pressure experiments and flow experiments were carried out using different fluid and the channel depth. The results indicated that the micropump could achieve a maximum static pressure head of 268 Pa at an applied voltage of 90 V. The maximum flow rate of the micropump-driven fluid could reach 106 μL/min. This paper analyzed the future of combining micropump with heat pipe to deal with heat dissipation of high power electronic chips. The maximum heat dissipation capacity of 87 W/cm2 can be realized by vaporizing the micropump-driven liquid on vaporizing section of the heat pipe.

摘要：Significant aerodynamic engine instability can occur during the operation of marine gas turbines as airflow enters the compressor through a 90°turning and causes inlet *** study adopts the method of simulating board equivalence to provide the target distortion flow field for ship *** characteristics of the flow field behind the simulated board are obtained through experiments and numerical simulations,through which the relationship between the height of the simulated board and the total pressure distortion is ***,the study summarizes the prediction formula to achieve a distortion prediction of 0.8%–7.8%.In addition,this work analyzes the effects of drilling methods and diameters on flow nonuniformity by drilling holes into the simulation *** results indicate that drilling holes on the board can weaken the nonuniformity of the flow field within a certain range and change the distribution pattern of total pressure in the ***,the total pressure distortion no longer changes significantly when the number of holes is too *** proposed double simulation board structure is capable of obtaining the following two types of distorted flow fields:symmetrical dual lowpressure zones and low-pressure zones with high distortion intensity at the compressor *** distortion equivalent simulation method proposed in this work can obtain various types of distortion spectra,thereby meeting the distortion parameter requirements for the antidistortion testing of marine engines.

摘要：Herein,two asymmetric hexacyclic fused small molecule acceptors(SMAs),namely BP4F-HU and BP4F-UU,were *** elongated outside chains in the BP4F-UU molecule played a crucial role in optimizing the morphology of blend film,thereby improving charge mobility and reducing energy loss within the corresponding ***,the PM6:BP4F-UU device exhibited a higher open-circuit voltage(V_(oc))of 0.878 V compared to the PM6:BP4F-HU device with a V_(oc)of 0.863 ***,a new wide bandgap SMA named BTP-TA was designed and synthesized as the third component to the PM6:BP4F-UU host binary devices,which showed an ideal complementary absorption spectrum in PM6:BP4F-UU *** addition,BTP-TA can achieve efficient intermolecular energy transfer to BP4F-UU by fluorescence resonance energy transfer(FRET)pathway,due to the good overlap between the photoluminescence(PL)spectrum of BTP-TA and the absorption region of ***,ternary devices with 15wt%BTP-TA exhibits broader photon utilization,optimal blend morphology,and reduced charge recombination compared to the corresponding binary ***,PM6:BP4F-UU:BTP-TA ternary device achieved an optimal power conversion efficiency(PCE)of 17.83%with simultaneously increased V_(oc)of 0.905 V,short-circuit current density(J_(sc))of 26.14 mA/cm^(2),and fill factor(FF)of 75.38%.

摘要：Al is considered as a promising lithium-ion battery(LIBs)anode materials owing to its high theoretical capacity and appropri-ate lithation/de-lithation ***,its inevitable volume expansion causes the electrode structure instability,leading to poor cyclic ***’s worse,the natural Al2O3 layer on commercial Al pellets is always existed as a robust insulating barrier for elec-trons,which brings the voltage dip and results in low reversible ***,this work synthesized core-shell Al@C-Sn pellets for LIBs by a plus-minus *** this proposal,the natural Al2O3 passivation layer is eliminated when annealing the pre-introduced SnCl2,meanwhile,polydopamine-derived carbon is introduced as dual functional shell to liberate the fresh Al core from re-oxidization and alle-viate the volume *** from the addition of C-Sn shell and the elimination of the Al2O3 passivation layer,the as-prepared Al@C-Sn pellet electrode exhibits little voltage dip and delivers a reversible capacity of 1018.7 mAh·g^(-1) at 0.1 A·g^(-1) and 295.0 mAh·g^(-1) at 2.0 A·g^(-1)(after 1000 cycles),***,its diffusion-controlled capacity is muchly improved compared to those of its counterparts,confirming the well-designed nanostructure contributes to the rapid Li-ion diffusion and further enhances the lithium storage activity.

摘要：目的:流体弹性不稳定性是引起换热器管束振动失效的最主要原因。鉴于目前有关两相横向流诱发管束弹性不稳定性的设计准则尚无一致结论,本文采用空气-水两相流体系,考察不同参数条件下换热器管束的弹性不稳定性。创新点:1.从避免发生弹性不稳定性的角度,确定适宜的管束排列方式和节径比;2.建立基于Connor准则的不稳定常数的确定方法,并提出新的推荐值。方法:1.实验研究两相流的流动条件和管束的几何特征对管束阻尼、振动特性及弹性不稳定性的影响;2.采用建立稳定区图的方法确定不稳定常数的推荐值;3.通过与其他研究成果的对比分析,验证本文推荐的不稳定常数的合理性和可靠性。结论:1.相比于阻力方向,升力方向上的阻尼比更小,也更易发生弹性失稳。2.四种排列管束的稳定性从高到低依次为:正三角形、正方形、转置正方形、转置正三角形。3.对于正方形和正三角形排列管束,推荐不稳定常数为4.0;对于转置正方形和转置正三角形排列管束,当质量阻尼参数小于或等于0.54时,推荐不稳定常数为1.1,反之,则推荐不稳定常数为1.5。

摘要：随着采矿进入深部地层,具有长服务年限的各类巷道交岔点围岩发生强烈破坏,需要明晰深部环境下交岔点围岩失效机理,以针对性地指导修复和补强作业。通过对多地矿井交岔点维护情况的调研,全面总结了连接型、交岔型、分岔型和旋岔型(环三角柱)四类16种交岔点类型,提出了三类交岔点的典型应用形式:单一大型交岔点、嵌套式两交岔点组和环三角岩柱式交岔点群。将现场交岔点的破坏情况分为围岩局部破坏、三角岩柱破坏和整体性破坏的三种级别,从灾害的诱因和来源上,提出了外部环境因素、自身结构属性和人为设计隐患的三类13种致灾因素,并详述了各种致灾因素的致灾路径。建立了三类典型应用形式下交岔点的精细化模型,对数值软件进行二次开发,引入了畸变能密度指标进行围岩的能量分析。研究表明,交岔点围岩的畸变能峰值在三角区岩柱内,增高系数在2.5左右。最大断面处围岩畸变能同样发生积聚,增高系数在1.5左右。因此,提出了交岔点的修复需以强化三角岩柱和大断面处围岩为重点,并对深井交岔点的修复提出了以三角岩柱和大断面段补强为主的针对性方案。本研究为深部交岔点的破坏因素分析、数值模拟指标引入和修复支护提供了参考。

摘要：铂(Pt)是质子交换膜燃料电池(PEMFCs)阳极氢氧化反应(HOR)中最先进的电催化剂.然而,Pt催化剂对CO(工业低成本氢燃料中的杂质)极度敏感从而中毒,这会引起器件性能的急剧衰退,导致器件运行成本高.因此,提高Pt催化剂的CO耐受性对PEMFCs的商业化推广至关重要.在此,我们设计合成了一种独特的PtNiW@WO_(x)核壳纳米线来提高Pt基催化剂对CO的耐受能力.机理研究表明,表面无定形的WO_(x)壳层可以作为分子围栏,在动力学上阻碍CO扩散到达Pt位点.在热力学上,Ni和W元素合金化产生的电子效应可以使Pt的d带中心降低,减弱CO在Pt位点上的化学吸附.此外,亲氧W元素可以加速水的解离,提供更多OH活性物种,促进CO的氧化脱附.因此,在1000ppm CO/H_(2)条件下,所设计的PtNiW@WO_(x)核壳纳米线催化剂表现出优异的HOR抗CO中毒性能,在4000 s后仍能保持超过90%的HOR电流密度,超过了原始的PtNi纳米线和目前报道的绝大多数Pt基催化剂.