摘要：High-energy-density(HED)fuels(***-10)are of great importance in safeguarding territorial air security,since they can increase the flight range and payload of military *** reduce the reliance on limited petroleum source,the production of HED fuel with renewable biomass feedstocks is highly *** currently,most of the synthetic biofuels,due to their intrinsic ring structure,are incapable of competing with JP-10 in terms of energy density and freezing *** emulating the structural characteristic of JP-10,we herein design and prepare a special C16 fused tetracyclic biofuel using renewable cyclopentanone and benzoquinone as *** to success depends on selective dehydration of vicinal diol(dimer of cyclopentanone)over Amberlyst-15 in[Hmim]*** Amberlyst-15/[Hmim]Cl system effectively suppresses the dominant pinacol-type rearrangement pathway and also exhibits good reusability for the *** hydrogen-bonding interaction between vicinal diol and imidazolium ring,as well as electrostatic force between carbocation intermediate and chloride anion contribute to the high diene *** compact ring framework gives rise to a density of 0.966 g/mL,combustion heat of 43.1 MJ/L,freezing point of‒67℃,and kinematic viscosity of 12.4 cSt,which are comparable to the properties of *** is expected that this as-prepared HED biofuel may potentially serve as a renewable alternative to petroleum fuel JP-10.

摘要：Exploring the production and application of clean energy has always been the core of sustainable *** a clean and sustainable technology,electrocatalysis has been receiving widespread *** is crucial to achieve efficient,stable and cheap ***,the traditional“trial and error”method is time-consuming,laborious and *** recent years,with the significant increase in computing power,computations have played an important role in electrocatalyst ***,it is still difficult to search for advanced electrocatalysts in the vast chemical space through traditional density functional theory(DFT)***,the development of machine learning and interdisciplinary integration will inject new impetus into targeted design of *** learning is able to predict electrochemical performances with an accuracy close to *** we provide an overview of the application of machine learning in electrocatalyst design,including the prediction of structure,thermodynamic properties and kinetic *** also discuss the potential of explicit solvent model combined with machine learning molecular dynamics in this ***,the favorable circumstances and challenges are outlined for the future development of machine learning in *** studies on electrochemical processes by machine learning will further realize targeted design of high-efficiency electrocatalysts.

摘要：Birefringence arises when the propagation speed and refractive index of light in an optically anisotropic crystal changes in response to the direction of ***,birefringence belongs to linear optical anisotropy and is a key parameter for linear optoelectronic functional crystals,such as birefringent crystals,which are widely used to modulate the polarization of light in optoelectronic areas[1].In terms of practical applications,there is still an urgent need for wide-bandgap birefringent crystals as they allow for the modulation of light polarization in short-wavelength UV waves and even in the deep-UV spectral region.

摘要：The selective detection of harmful gases is of great significance to human health and air quality,triggering the need for special customizations of sensing material *** this study,we prepared a novel Sn S_(2)/black phosphorus(BP)two-dimensional(2D)-2D heterostructure via the in situ hydrothermal growth of Sn S_(2)nanosheets on exfoliated BP lamellae for NO_(2)sensing *** the Sn S_(2)/BP composite,the holes with high oxidizability in p-type BP could oxidize Sn^(2+)into Sn^(4+),thus inhibiting the formation of Lewis acidic S *** Sn^(2+)/Lewis acidity suppression of the composite was further confirmed by X-ray photoelectron spectroscopy and acidic double-layer capacitance analyses,and promoted the adsorption and detection of acidic NO_(2).Owing to its valence and Lewis acidity engineering,the Sn S_(2)/BP heterostructure sensor could detect trace levels of NO_(2)as low as 100 ppb(parts per billion)with high response,fast response/recovery,good stability,and selectivity at room *** high absorption energy of NO_(2)(à0.74 e V),as indicated by the density functional theory calculations,suggests that NO_(2)was chemically adsorbed on the Sn S_(2)/BP surface,which was also evidenced by the in situ Raman spectroscopy *** work opens up interesting opportunities for the rational design of highly efficient NO_(2)gas sensors through Lewis acidity modification and interface engineering.

摘要：助推段拦截时间窗口极短,要求导弹须具备高速、高加速能力,同时由于目标弹道导弹在助推阶段仍在加速,要求拦截导弹的制导方案需具备应对目标机动的能力。通过分析助推段拦截导弹的特性,建立弹道仿真模型,并依据拦截导弹飞行全过程要求的制导机制性能,详细设计助推段拦截导弹在初制导、中制导、末制导阶段下的制导律,研究不同制导方案对导弹拦截性能的影响,并分析了不同导弹最大速度的拦截效果。结果表明:助推段拦截导弹的中制导采用预测命中点导引律能够降低视线角速率,使弹道更为平直,末制导采用修正比例导引律可以降低需用过载,提高拦截性能;能量越高的导弹,其速度特性、飞行性能越高,同时所需拦截时间越短,拦截效果越好。

摘要：目的:核主泵轴向力过大容易造成水润滑轴承磨损,因此在保证扬程和效率性能的同时需要降低核主泵轴向力。本文旨在建立目标性能与叶轮几何形状的函数关系,探究基于伴随求解的扭曲叶轮的变形方案,在保证扬程不变的条件下同步优化叶轮的轴向力和效率,并找到影响该综合性能的叶轮关键区域。创新点:1.提出一种同步改进多个目标性能的叶轮形状优化方法;2.将伴随求解和径向基函数网格变形相结合以实现核主泵叶轮三维曲面优化。方法:1.通过理论分析,建立基于径向基函数网格变形的伴随优化方法,并在开源平台编写迭代程序;2.通过公式推导,构建扬程、效率和轴向力对应的目标函数(公式(19)^(21)),并运用正交实验确定各个目标函数的参数因子;3.通过迭代计算,在保证扬程不变的条件下实现轴向力和效率的同步优化,确定影响该综合性能的关键区域(图8),并获得叶轮的改进设计方案;4.通过流场分析,对比改进前后流场内部的压力和流速分布情况(图9和10),并验证改进方案的可行性和有效性。结论:1.与传统的随机算法相比,该优化方法直接沿梯度方向进行迭代优化,可以避免使用大量样本数据来寻找优化路径;2.该优化方法将伴随求解和径向基函数网格变形相结合,实现了流场计算和结构变形的自动化,可以保证流场网格光滑高效地更迭;3.叶轮靠近出口边的下半部分是同步优化核主泵轴向力和效率的关键区域。

摘要：Incorporating functional molecules into molecular junc- tions as active components is a topic of major interest in the field of molecular electronics [1-7]. Many efforts have been devoted to fabricating switchable molecular elec- tronic devices that are responsive to external stimuli [8,9]. Among various stimuli （e.g., redox process [ 10], pH[ 11 ], magnetic field [12]）, light offers a dean, non-invasive, low-cost and easily addressable way for triggering mole- cular switches in electrical devices [13,14].

摘要：界定数字人文项目的核心内涵，识别数字人文项目的特征属性，探究数字人文项目的潜在价值，明晰数字人文项目的实践路径，对推进数字人文研究具有重要价值。文章分析近5年35项国际数字人文奖冠军项目，基于“特征识别-目标驱动-实践路径”顺向思维逻辑，回答数字人文项目“何为-何能-何以”等基础性问题。研究发现：数字人文项目具有可追溯性、可延展性、可参与性、可协同性、可持续性五大特点，相互之间始终保持良性协调共存；现实驱动、政策引导、技术赋能、服务升级、人员转型是数字人文项目可持续发展的核心目标驱动力；未来可基于理念层、技术层、资源层、保障层4个层面进一步深化数字人文项目的实践方向与建设内容。

摘要：设计了一种叶片式脉动发生器,并进行了实验。实验结果表明:通过周期性开、闭管路的方法,叶片式脉动发生器可以实现对流体的脉动作用,获得脉动流。该脉动发生器具有沿程脉动效果损失低,所产生脉动作用具有传递性的特点。形成脉动流的脉动振幅随脉动频率的变化而有所改变。引入叶片式脉动发生器会对管路流速产生一定的影响,脉动频率与流速间呈现非线性关系。

摘要：利用无源声信号的到达时差对目标入水点进行定位在浅海中已有成功应用,但在深海条件下因测量区域变大、声传播路径弯曲、测量条件受限等因素,定位性能不确定度增加.针对这一问题,建立基于水平分层介质假设的多基站时差定位模型,对比了等声速介质信道与水平分层介质信道定位求解的性能差异,并结合西北太平洋夏季环境条件下的仿真算例对模型进行了验证.研究揭示了有明显等效声速差异条件下的深海时差交会变异性特征,当两基站的等效声速相接近时,等时差线趋于标准双曲线样式;当两基站的等效声速相差较大时,等时差线呈现不规则分布,一侧趋于闭合,另一侧趋于平行,且多个基站等时差线均位于闭合一侧时,定位性能明显下降.在测量系统论证和设计时应充分考虑时差交会特性,结合具体海区环境条件合理选取基阵构型和布设深度.