航空发动机终端威胁作用机理和威胁模式分析

战机及其配装的发动机在战场执行任务时,不可避免地会遭遇敌方防空武器的威胁,终端威胁对施加损伤起关键作用。针对发动机(飞机)在战场执行攻击任务时可能遭遇的不同类型威胁,重点对终端威胁作用机理和威胁模式开展分析。从终端威胁产物杀伤机理(威胁机理)出发,描述了穿透物、破片、燃烧物质、爆炸冲击波、高能激光和生化制剂等常见终端威胁产物的输出特性。在此基础上,对航空发动机典型7大部件遭受的威胁模式开展分析,给出了相关威胁模式可能给各大部件带来的损伤模式。上述威胁分析结果可供发动机及部件易损性分析时借鉴,也可供发动机生存力或易损性设计参考。

CXC趋化因子受体3对神经系统疾病发生发展影响的研究进展

趋化因子及其受体在神经系统疾病中起重要作用,其中CXC趋化因子受体3 (CXCR3)是细胞之间传递信息的重要介质,不仅在诱导炎性趋化和肿瘤细胞恶性生物学行为中起作用,在神经系统疾病中也发挥重要调控作用。CXCR3及其配体可直接或间接参与神经炎症和神经免疫等反应,有望成为多发性硬化、阿尔茨海默病及胶质瘤等疾病治疗的靶点。现对CXCR3及其相应配体在神经系统疾病如多发性硬化、神经系统肿瘤、神经退行性疾病和神经性疼痛等方面的表达及影响,及其与CXCR3配体间的关联进行综述,揭示CXCR3与疾病关系的机制,探讨CXCR3作为早期诊断生物标志物和药物干预靶点的潜力,为CXCR3对神经系统疾病发生发展影响的研究提供参考。

啶虫脒在豇豆腌制过程中的生物转化

本研究通过测定在豇豆腌制过程中啶虫脒的消散和转化行为,同时通过毒理学软件ECOSAR和毒性评估软件工具T.E.S.T.进一步预测了啶虫脒及其转化产物(transformation products,TPs)的毒性。结果表明在豇豆腌制过程中啶虫脒发生明显的降解行为,其降解速率常数为0.96761,半衰期为(34.95±0.78)d。在豇豆腌制过程中鉴定出了4种啶虫脒的TPs,其中TP1和TP2的大鼠口服致死剂量分别为358.17 mg/kg和385.7 mg/kg,属于“有害”等级,且其发育毒性较母体明显增加。此外,在实际样品检测过程中,所有样品中啶虫脒以及转化产物TP1、TP2和TP3均有检出,啶虫脒的最高质量浓度为473.8μg/L,中位质量浓度为41.1·μg/L。这些研究结果揭示了啶虫脒在豇豆腌制过程中的降解及生物转化情况,有助于更好地了解腌制食品可能存在的健康风险。

超高效液相色谱-串联质谱法测定燕麦粉和小米粉中白僵菌素和恩镰孢菌素

目的建立一种超高效液相色谱-串联质谱法测定谷物性食品燕麦粉和小米粉中白僵菌素(beauvercin,BEA)、恩镰孢菌素A、恩镰孢菌素A_(1)、恩镰孢菌素B和恩镰孢菌素B_(1)残留的分析方法。方法样品采用乙腈-水-甲酸(84:15:1,V:V:V)提取、经过Oasis Prime HLB固相萃取柱净化后,WatersBEH C_(18)色谱柱(100 mm×2.1 mm,1.8μm)分离,在正离子模式下,以5 mmol/L乙酸铵水溶液-乙腈为流动相进行梯度洗脱,在多反应监测模式下进行定性定量检测分析,基质匹配标准曲线外标法定量。结果BEA和4种恩镰孢菌素在各自的线性范围内具有良好的线性关系(r^(2)>0.999),方法检出限为0.02~0.05μg/kg,定量限为0.05~0.15μg/kg。按线性范围的最低浓度、中浓度和最高浓度3个水平进行加标回收实验,燕麦粉和小米粉的平均回收率分别是83.6%~105.2%和88.5%~104.2%,相对标准偏差分别为1.3%~8.2%和1.3%~3.2%(n=6)。对北京市采集的10份燕麦粉和10份小米粉样品进行检测,5种化合物均有不同程度检出,其中,恩镰孢菌素B和恩镰孢菌素B_(1)的检出率为100%。结论本方法简单快速、准确性好、灵敏度高,可以实现对燕麦粉和小米粉中白僵菌素和恩镰孢菌素进行准确的定性定量。

药物减轻心肌缺血再灌注损伤机制研究的进展

心肌缺血再灌注损伤常见于心肌梗塞、心肌缺血等,其发病率、死亡率高,且缺乏防治措施。积极探究防治心肌缺血再灌注损伤是临床研究的热点,近5年有关药物减轻心肌缺血再灌注损伤及其机制的研究较多,也取得了一些进展。本文着重介绍近5年关于药物通过抑制铁死亡、细胞凋亡、坏死性凋亡、细胞焦亡、氧化应激、钙超载、自噬调控、内质网应激、能量代谢等机制减轻心肌缺血再灌注损伤的实验研究和临床观察,及利用纳米技术、冠状动脉内给药技术等防治心肌缺血再灌注损伤的新成果,为心肌缺血再灌注损伤防治和研究提供理论依据。

舰载涡扇发动机高低温起动试验与分析

为验证某舰载涡扇发动机在高低温环境条件下起动特性,基于高低温起动验证试车台,通过模拟高低温进气和保温条件,开展了采用RP-3燃油和RP-5燃油的涡扇发动机高低温起动性能对比试验。分析了不同环境温度下发动机起动点火性能的变化规律;对比了不同环境温度、燃油种类、转速上升率对发动机起动性能的影响。试验结果表明,大气温度由60℃下降到-20℃,主燃烧室供油到点着火时间延长约1~2 s;在-20~60℃内,采用RP-3和RP-5两种燃油,发动机起动性能基本一致;给定转速上升率降低0.1%/s,低温起动时间延长0.01~0.06(相对值),在高压换算转速n_(Hcor)=0.3~0.5(相对值)转速范围内,反馈转速上升率与给定上升率最大差异为28.2%;整个起动转速范围内,主燃油供油流量最高下降10.8%,燃油总管压力p_(f)与高压压气机出口压力p_(31)之差最高下降10.1%。

碱性过氧化氢改性预处理对玉米芯不溶性膳食纤维的理化性质及功能特性的影响

采用不同质量分数的碱性过氧化氢(AHP)对玉米芯不溶性膳食纤维(IDF)进行改性预处理,评估比较了AHP改性前后玉米芯IDF的理化性质和功能特性。结果表明,改性后玉米芯中IDF的持水力(WHC)、持油力(OHC)、吸水膨胀力(WSC)和葡萄糖吸附能力(GAC)明显提高。与未经处理的IDF相比,改性后WHC、OHC、WSC和GAC分别由(2.24±0.03)g/g、(1.88±0.01)g/g、(1.97±0.16)mL/g、(102.16±4.98)mg/g提高至(4.36±0.18)g/g、(3.18±0.04)g/g、(2.94±0.08)mL/g、(217.77±18.95)mg/g。在pH为2.0时,改性后玉米芯IDF的亚硝酸根离子吸附能力(NAC)明显增加,2.0%AHP改性后达到最大值68.45μg/g。此外,扫描电子显微镜(SEM)观察到AHP改性后表面出现褶皱,并具有多孔网状结构。傅里叶变换红外光谱(FT-IR)和X射线衍射(XRD)图谱表明,AHP改性能够降解玉米芯IDF中的半纤维素和木质素。总体来说,AHP改性可以有效地改善玉米芯IDF的性能。

基于ICF的社区老年人健康相关康复服务架构与策略探析

目的 从社区与人群视角科学评估老年人健康相关康复服务需求,构建社区老年人健康相关康复服务框架。方法 从社区层面分析老年人健康相关康复服务存在的局限性,并基于《国际功能、残疾和健康分类》(ICF)框架构建社区老年人健康相关康复服务框架并提出实施路径。结果 本研究在分析国内外现有社区康复服务的评估、供给和模式的基础上,结合我国的新时代背景和现实要求,阐释了社区老年人健康相关康复服务的内涵,提出以ICF为指导构建社区老年人健康相关康复服务框架,从提高领导力和政策、筹资、人力、服务供给、技术、数智赋能等方面提出推动社区老年人健康相关康复服务的实施策略,为落实推动应对人口老龄化国家战略和健康中国战略提供参考和借鉴。结论 要持续加快推动健康相关康复服务能力建设,增加健康相关康复服务供给,满足群众多样化健康相关康复服务需求。

RCEP背景下我国新能源汽车出口影响因素研究——基于贸易引力模型

《区域全面经济伙伴关系协定》(RCEP)的签署促进了中国与东盟等成员国的经济合作,创建了更高效、开放的贸易环境。研究UN COMTRADE和eps数据库中我国与RCEP成员国之间的新能源汽车进出口贸易数据,利用贸易引力模型,得到结果:东道国GDP、商品贸易条件、人口规模和汇率等影响中国新能源汽车出口。研究不仅丰富了我国对RCEP成员国出口贸易影响因素研究的相关文献,为我国加强与RCEP成员国的经济合作,助推新能源汽车产业出口的可持续发展提供启示。

Determining beam transverse absolute position by triangulation of multi-electrode signal phase differences

Accurate measurement of the transverse position of a beam is crucial in particle accelerators because it plays a key role in determining the beam parameters.Existing methods for beam-position measurement rely on the detection of image currents induced on electrodes or narrow-band wake field induced by a beam passing through a cavity-type structure.However,these methods have limitations.The indirect measurement of multiple parameters is computationally complex,requiring external calibration to determine the system parameters in advance.Furthermore,the utilization of the beam signal information is incomplete.Hence,this study proposes a novel method for measuring the absolute electron beam transverse position.By utilizing the geometric relationship between the center position of the measured electron beam and multiple detection electrodes and by analyzing the differences in the arrival times of the beam signals detected by these electrodes,the absolute transverse position of the electron beam crossing the electrode plane can be calculated.This method features absolute position measurement,a position sensitivity coefficient independent of vacuum chamber apertures,and no requirement for a symmetrical detector electrode layout.The feasibility of this method is validated through numerical simulations and beam experiments.

Bunch-length measurement at a bunch-by-bunch rate based on time–frequency-domain joint analysis techniques and its application

This paper presents a new technique for measuring the bunch length of a high-energy electron beam at a bunch-by-bunch rate in storage rings.This technique uses the time–frequency-domain joint analysis of the bunch signal to obtain bunch-by-bunch and turn-by-turn longitudinal parameters,such as bunch length and synchronous phase.The bunch signal is obtained using a button electrode with a bandwidth of several gigahertz.The data acquisition device was a high-speed digital oscilloscope with a sampling rate of more than 10 GS/s,and the single-shot sampling data buffer covered thousands of turns.The bunch-length and synchronous phase information were extracted via offline calculations using Python scripts.The calibration coefficient of the system was determined using a commercial streak camera.Moreover,this technique was tested on two different storage rings and successfully captured various longitudinal transient processes during the harmonic cavity debugging process at the Shanghai Synchrotron Radiation Facility(SSRF),and longitudinal instabilities were observed during the single-bunch accumulation process at Hefei Light Source(HLS).For Gaussian-distribution bunches,the uncertainty of the bunch phase obtained using this technique was better than 0.2 ps,and the bunch-length uncertainty was better than 1 ps.The dynamic range exceeded 10 ms.This technology is a powerful and versatile beam diagnostic tool that can be conveniently deployed in high-energy electron storage rings.

A process-oriented approach for identifying potential landslides considering time-dependent behaviors beyond geomorphological features

Geomorphological features are commonly used to identify potential landslides.Nevertheless,overemphasis on these features could lead to misjudgment.This research proposes a process-oriented approach for potential landslide identification that considers time-dependent behaviors.The method integrates comprehensive remote sensing and geological analysis to qualitatively assess slope stability,and employs numerical analysis to quantitatively calculate aging stability.Specifically,a time-dependent stability calculation method for anticlinal slopes is developed and implemented in discrete element software,incorporating time-dependent mechanical and strength reduction calculations.By considering the time-dependent evolution of slopes,this method highlights the importance of both geomorphological features and time-dependent behaviors in landslide identification.This method has been applied to the Jiarishan slope(JRS)on the Qinghai-Tibet Plateau as a case study.The results show that the JRS,despite having landslide geomorphology,is a stable slope,highlighting the risk of misjudgment when relying solely on geomorphological features.This work provides insights into the geomorphological characterization and evolution history of the JRS and offers valuable guidance for studying slopes with similar landslide geomorphology.Furthermore,the process-oriented method incorporating timedependent evolution provides a means to evaluate potential landslides,reducing misjudgment due to excessive reliance on geomorphological features.

GPa-level pressure-induced enhanced corrosion resistance in TiZrTaNbSn biomedical high-entropy alloy

TiZrTaNb-based high-entropy alloys(HEAs)are research frontier of biomedical materials due to their high hardness,good yield strength,excellent wear resistance and corrosion resistance.Sn,as an essential trace element in the human body that plays a significant role in physiological process.It has stable chemical properties and a low elastic modulus.In this study,a new material,TiZrTaNbSn HEAs,was proposed as a potential biomedical alloy.The Ti_(35)Zr_(25)Ta_(15)Nb_(15)Sn_(10)biomedical high-entropy alloys(BHEAs)were successfully prepared through an arc melting furnace and then remelted using a German high-temperature and high-pressure apparatus under GPa-level(4 GPa and 7 GPa).The precipitation behavior of the needle-like HCP-Zr_(5)Sn_(3)phase that precipitates discontinuously at the grain boundary was successfully controlled.The phase constitution,microstructure,and corrosion resistance of the alloy were studied.The results show that the needle-like HCP-Zr_(5)Sn_(3)phase is eliminated and the(Zr,Sn)-rich nano-precipitated phase is precipitated in the microstructure under high pressure,which leads to the narrowing of grain boundaries and consequently improves the corrosion resistance of the alloy.In addition,the formation mechanisms of(Zr,Sn)-rich nanoprecipitates in BHEAs were discussed.More Zr and Sn dissolve in the matrix due to the effect of high pressure,during the cooling process,they precipitate to form a(Zr,Sn)-rich nano-precipitated phase.

聚集诱导发光铂(Ⅱ)配合物对硝基芳烃的高效发光检测

合成了一例三苯胺基团修饰的铂(Ⅱ)配合物PtppyTPA,并详细地表征了其结构及光物理性质。研究表明,三苯胺基团可有效激活PtppyTPA的聚集诱导发光(AIE)性能,使其在含水量为50%的乙腈中呈现显著的发光增强。以AIE活性的PtppyTPA为发光探针实现了对4种硝基芳烃包括硝苯地平(Nifedipine,NFD)、5-氯-2-硝基三氟甲苯(5-chloro-2-nitrotrifluorotoluene,ClNTFT)、4-溴-1-氟-2-硝基苯(4-bromo-1-fluoro-2-nitrobenzene,BrFNBz)及3-硝基三氟甲苯(3-nitrotrifluorotoluene, NTFT)的发光检测,利用Stern-Volmer方程拟合检测数据并计算了检测效率及检测限。PtppyTPA对上述硝基芳烃的检测效率分别为11.12,0.27,0.25,0.21 L/mmol;检测限分别为7.1,291.0,314.3,374.2μmol/L。PtppyTPA对NFD具有最高的检测效率和最低的检测限。前线轨道能级及光谱交叠实验表明,PtppyTPA对NFD、ClNTFT、BrFNBz及NTFT的检测机理为电子转移。

Lobe-dominatedγ-Ray Emission of Compact Symmetric Objects

Theγ-ray emitting compact symmetric objects(CSOs)PKS 1718-649,NGC 3894,and TXS 0128+554 are lobedominated in the radio emission.In order to investigate theirγ-ray radiation properties,we analyze the~14yr Fermi/LAT observation data of the three CSOs.They all show the low luminosity(1041-1043 erg s-1)and no significant variability in theγ-ray band.Theirγ-ray average spectra can be well fitted by a power-law function.These properties ofγ-rays are clearly different from theγ-ray emitting CSOs CTD 135 and PKS 1413+135,for which theγ-rays are produced by a restarted aligned jet.In the L_(γ)-Γ_(γ)plane,the three CSOs are also located at the region occupied by radio galaxies(RGs)while CTD 135 and PKS 1413+135 display a similar feature to blazars.Together with a similar radio emission property toγ-ray emitting RGs Cen A and Fornax A,we speculate that theγ-rays of the three CSOs stem from their extended mini-lobes.The broadband spectral energy distributions of the three CSOs can be well explained by the two-zone leptonic model,where theirγ-rays are produced by the inverse Compton process of the relativistic electrons in extended regions.By extrapolating the observed Fermi/LAT spectra to the very high energy band,we find that TXS 0128+554 among the three CSOs may be detected by the Cherenkov Telescope Array in the future.

GRB 210323A:Signature of Long-lasting Lifetime of Supra-massive Magnetar as the Central Engine from the Merger of Binary Neutron Star

Theoretically,a supra-massive neutron star or magnetar may be formed after the merger of binary neutron stars.GRB210323A is a short-duration gamma-ray burst(GRB)with a duration of lasting~1 s.The light curve of the prompt emission of GRB 210323A shows a signal-peaked structure and a cutoff power-law model can adequately fit the spectra with E_p=1826±747.More interestingly,it has an extremely long-lasting plateau emission in the X-ray afterglow with a duration of~10^(4)s,and then follows a rapid decay with a decay slope~3.2.This temporal feature is challenging by invoking the external shock mode.In this paper,we suggest that the observed long-lasting X-ray plateau emission is caused by the energy injection of dipole radiation from supra-massive magnetar,and the abrupt decay following the longlasting X-ray plateau emission is explained by supra-massive magnetar collapsing into a black hole.It is the short GRB(SGRB)with the longest X-ray internal plateau emission powered by a supra-massive neutron star.If this is the case,one can estimate the physical parameters of a supra-massive magnetar,and compare with other SGRBs.We also discuss the possible gravitational-wave emission,which is powered by a supra-massive magnetar and its detectability,and the possible kilonova emission,which is powered by r-process and magnetar spin-down to compare with the observed data.

数字化转型、内外部监督与企业声誉

党的二十大报告提出了建设现代化产业体系的战略部署,对加快发展数字经济、完善中国特色现代企业制度和加快建设世界一流企业提出了更高的要求。以2012—2021年中国沪深A股上市公司为研究对象,考察数字化转型对企业声誉的影响。研究结果表明:数字化转型对企业声誉具有促进作用,机构持股行为在两者之间发挥了部分中介作用,内外部监督在数字化转型对企业声誉的影响中发挥调节作用。非国有、高社会责任和高信息披露企业数字化转型能够显著提高企业声誉。

不同类型铝硅镀层热成型钢的耐蚀性研究

[目的]铝硅镀层热成型钢的镀层厚度对其防腐性能影响较大,有必要对汽车上使用的铝硅镀层热成型常规镀层板(镀层厚度20~33μm)、薄镀层板(镀层厚度6~14μm)及变厚度板的耐蚀性进行比较。[方法]采用中性盐雾(NSS)试验对热成型前后试样的耐蚀性进行考察。[结果]热成型前,常规镀层板在NSS试验1109 h时才出现红锈,薄镀层板在283 h后便出现红锈,变厚度板薄区618 h后出现红锈;热成型及电泳后,常规镀层板和薄厚度板的单边扩蚀宽度分别为0 mm和4.0 mm,变厚度板上基板厚度为2.3、2.0和1.8 mm的区域的单边扩蚀宽度分别为0.5、2.0和2.0 mm。[结论]热成型前,铝硅镀层板的耐蚀性与镀层的表面层隔离作用有关;热成型及电泳后,镀层的扩散层厚度对腐蚀的影响较大,变厚度板的防腐性能较薄镀层板好,但比常规镀层板差。

水泥、粉煤灰稳定钢渣铁矿废石混合料路用性能试验研究

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