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Numerical exploration on jet oscillation mechanism of counterflowing jet ahead of a hypersonic lifting-body vehicle

science china(Technological {2.) 2018年第7期61卷 1056-1071页

作者： DENG Fan xie Feng HUANG wei DONG Hao ZHANG Dong science and Technology on space Physics Laboratory China Academy of Launch Vehicle TechnologyBeijing 100076China Hypervelocity Aerodynamics Institute China Aerodynamics Research and Development CenterMianyang 621000China science and Technology on Scramjet Laboratory National University of Defense TechnologyChangsha 410073China College of Aerospace Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China National Key Laboratory of Aerospace Flight Dynamics Northwestern Polytechnical UniversityXi'an 710072China

Numerical investigation of a supersonic jet from the nose of a lifting-body vehicle opposing a hypersonic flow with the freestream Mach number being 8.0 at 40 km altitude was carried out by solving the three-dimensional, time-accurate Navier-Stokes equations with a hybrid meshes approach. Based on the analysis of the flow field structures and aerodynamic characteristics, the behaviours relevant to the LPM jet were discussed in detail, including the drag reduction effect, the periodic oscillation and the feedback loop. The obtained results show that the flow oscillation characteristic of the LPM jet is low-frequency and high-amplitude while that of the SPM jet is high-frequency and low-amplitude. Compared with the clearly dominant frequencies of the LPM jet, the SPM jet exhibits a broad-band structure. The LPM jet can sustain drag reduction effect until the angle of attack is 8°, and the lift-to-drag ratio of the vehicle is effectively improved by 6.95% at angle of attack of 6°. The self-sustained oscillation process was studied by a typical oscillating cycle of the drag force coefficient and the variation of the instantaneous pressure distribution,which reveals an off-axial flapping motion of the conical shear layer. The variation of the subsonic recirculation zone ahead of the vehicle nose strengthens the understanding of the jet behavior including the source of instability in the long penetration mode and the mechanism of the feedback loop. The aim of this paper is to advance the technology readiness level for the counterflowing jet applied as an active control technology in hypersonic flows by gaining a better insight of the flow physics.

关键词： hypersonic lifting-body vehicle counterflowing jet LPM periodic oscillation

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顶空固相微萃取-气质联用法测定三过氧化三丙酮

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化学研究与应用 2024年第1期36卷 197-202页

作者：解伟亚朱军胡灿梅宏成朱晓晗中国人民公安大学侦查学院北京100038 公安部鉴定中心北京100038

三过氧化三丙酮(TATP)的检测分析对于明确爆炸原因,进而对爆炸案件侦破具有重要意义。固相微萃取(SPME)-气质联用法是检测爆炸现场复杂基质中微量TATP的有力手段,已被用于TATP的分析。考虑到商品化SPME涂层众多,有必要系统考察不同涂层... 详细信息

三过氧化三丙酮(TATP)的检测分析对于明确爆炸原因,进而对爆炸案件侦破具有重要意义。固相微萃取(SPME)-气质联用法是检测爆炸现场复杂基质中微量TATP的有力手段,已被用于TATP的分析。考虑到商品化SPME涂层众多,有必要系统考察不同涂层的萃取效果,以提升萃取效率。为此,文章系统比较了5种不同SPME涂层对TATP的萃取效果,并优化了SPME萃取条件,包括萃取温度、萃取时间和解吸温度。结果表明,使用PDMS涂层,在萃取温度3.℃,萃取时间5 min,解吸温度180℃条件下,萃取效果最佳。该方法在0.1~10μg·mL^(-1)范围内的线性良好(R~2.0.999),检出限为0.02.μg·mL^(-1),比已有方法低一个数量级。6次独立测试结果的相对标准偏差为2.4%,加标回收率为93.2.~101.9%,表明重复性和准确性较好。基于上述方法,成功应用于接触后转移的TATP的检测,为痕量TATP残留物的分析提供了技术参考。

关键词：三过氧化三丙酮顶空固相微萃取气质联用法

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南京梅雨降水同位素组成从事件到年际尺度的变化特征

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应用生态学报 2024年第4期35卷 951-960页

作者：张昊肖薇谢成玉胡勇博楚淏然王晶苑李旭辉南京信息工程大学中国气象局生态系统碳源汇重点开放实验室大气环境中心南京210044 生态环境部卫星环境应用中心北京100094 中国科学院地理科学与资源研究所生态系统网络观测与模拟重点实验室北京100101 耶鲁大学环境学院美国纽黑文06511

梅雨降水量占季风区全年降水量的40%~50%,为了厘清梅雨降水同位素从事件到年际尺度上的变化特征及其影响因素,本研究分析了2.15—2.2.年南京梅雨期间降水同位素特征,使用具有比湿分析的混合单粒子拉格朗日综合轨迹模型(HYSPLIT)分析了... 详细信息

梅雨降水量占季风区全年降水量的40%~50%,为了厘清梅雨降水同位素从事件到年际尺度上的变化特征及其影响因素,本研究分析了2.15—2.2.年南京梅雨期间降水同位素特征,使用具有比湿分析的混合单粒子拉格朗日综合轨迹模型(HYSPLIT)分析了南京梅雨降水同位素的水汽来源和影响因素。结果表明:1)南京大气降水同位素组成夏季贫化、冬季富集,氘盈余(d_(x))夏低冬高,梅雨降水同位素组成较全年平均水平更为贫化;2.梅雨降水δ^(2.H和δ^(18)O与局地气象条件无显著相关关系;但雨量较小的降水事件中d_(x)较低,反映出云下二次蒸发的影响;梅雨降水量较多的年份,梅雨期间平均d_(x)明显较高;3.低纬度南海源区和西太平洋源区为梅雨提供水汽,水汽源地的转换会导致连续降水过程中同位素信号的突变。本研究能为季风区降水同位素研究提供数据支持,并为深入理解梅雨降水机理和研究东亚季风区大气环流季节变化提供参考。

关键词：降水同位素梅雨水汽源地氘盈余二次蒸发

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Instructional Mutation Ant Colony Algorithm in Application of Reservoir Operation Chart Optimization

Instructional Mutation Ant Colony Algorithm in Application o...

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2.10 International Conference on Remote Sensing (ICRS 2.10)

作者： Shan YU The New and Renewable Energy of beijing Key Laboratory North china Electric Power University beijing {3. Chang-ming JI wei xie Fang LIU The New and Renewable Energy of beijing Key Laboratory North china Electric Power University beijing {3.

Guided by the chart that made according to the conventional method,the reservoir operation often cannot develop the maximum economic benefits,and a certain optimizing space exists in such a *** on the basic ant colony algorithm（ACA）,the mutation part improved with instruction in this paper was applied to the optimization of reservoir chart to auto-adjust the dispatching *** improvement enhances the global search ability of algorithm and makes full use of the historical and observed data,so that the algorithm can converge to the global optimal solution faster and *** the application,the instructional mutation ACA（IMACA）verifies the obvious optimization effect of the reservoir chart and remarkable economic benefit.

关键词： ant colony algorithm reservoir operation operation chart optimization

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Synthesis of hierarchical sieve-like mesoporous silica nanoparticle aggregates via centrifugal method for drug delivery system

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chinese Chemical Letters 2018年第12期29卷 1804-1810页

作者： Qin Gao Wensheng xie Lingyun Zhao Yu Wang wei Zhang Qiang Cai School of Materials science&Engineering Tsinghua UniversityBeijing 100084China State Key Laboratory of New Ceramics and Fine Processing Advanced Materials of Ministry of Education of ChinaTsinghua UniversityBeijing 100084China National center for Nanoscience and Technology Beijing 100190China

A facile approach towards the synthesis of a novel hierarchical sieve-like structure of mesoporous silica nanoparticle aggregates(hsMSNA) is reported using a centrifugal method at room temperature, based on the Kelvin-Helmholtz instability and soft-template method. The developed approach is simple and can potentially be applied for scaled-up preparation. Importantly, scanning electron microscopy,transmission electron microscopy, small-angle X-ray diffraction, and nitrogen adsorption-desorption experiments characterize the mesoporous silica as hsMSNA consisting of 40-100 nm mesoporous silica nanoparticles piled at 1-2.μm cylindrical pores in sieve-like tissues. Further, various pore sizes and sievemesh-, and vesicular-like structures can be obtained by adjusting the reaction conditions. The BrunauerEmmett-Teller specific surface area is as large as 500 m~2.g with a 47 cm~3.g pore volume, facilitating easy drug loading and delivery. Cytotoxicity assays show that the samples are not cytotoxic under a high concentration of 2.0μg/mL. Finally, the high drug encapsulation efficiency and sustained release behaviors indicats the considerable potential of the hsMSNA as a drug delivery system in the field of nanomedicine.

关键词： Mesoporous silica Hierarchical structure Interface growth Centrifugal method Drug delivery system

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Catalytic performance of Nb2.5 modified Ru/CeO2.for dichloromethane oxidation

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Progress in Natural science:Materials International 2023年第4期33卷 486-494页

作者： Wencheng Hao Zhiwei Wang Shaohua xie Lu wei Zhiquan Hou Yuxi Liu Hongxing Dai Jiguang Deng beijing Key Laboratory for Green Catalysis and Separation Key Laboratory of Beijing on Regional Air Pollution Control Faculty of Environment and Life Beijing University of Technology Department of Civil Environmental and Construction Engineering Catalysis Cluster for Renewable Energy and Chemical Transformations(REACT) Nano Science Technology Center(NSTC) University of Central Florida

1 wt% Ru/5 wt% Nb2.5/CeO2.RuNbCe) catalyst was synthesized via the incipient wetness impregnation method, and measured for the catalytic oxidation of dichloromethane(DCM). The physicochemical properties of catalysts were determined used various characterization techniques. Compared with 1 wt% Ru/CeO2. 5 wt%Nb2.5/CeO2. CeO2. 1 wt% Ru/xNb2.5/CeO2.x = 1 wt%, 2.wt%, and 3.wt%) and 1 wt% Ru/yMOn/CeO2.M =Co, Cr, Fe, Mg, Cu; y = 5 wt%), the addition of 5 wt% Nb2.5obviously improved the catalytic performance of 1 wt% Ru/CeO2. with the T90%and apparent activation energy(Ea) being 2.7℃ and 43.5 kJ/mol, respectively, and less formation of polychlorinated byproducts at {13. velocity(SV) = 15,000 mL g-1h-1. The RuNbCe catalyst showed good thermal and hydrothermal stability, as well as HCl-resistance performance. We deduced that the higher oxidation performance of the RuNbCe catalyst may be attributed to the suitable acidic sites, good redox capacity, high surface adsorbed oxygen species concentration, and the strong interaction among Ru, Nb2.5and CeO2. The RuNbCe catalyst has the potential to be applied for the elimination of chlorinated volatile organic compounds(CVOCs).

关键词： Ru/Nb2.5/CeO2 dichloromethane oxidation Catalytic stability Acidic sites CVOCs removal

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Ternary ReS_(2.1-x))Se_(2.) alloy saturable absorber for passively Q-switched and mode-locked erbium-doped all-fiber lasers

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Photonics research 2019年第3期7卷 283-288页

作者： CHENXI DOU WEN WEN JUNLI WANG MENGYUAN MA LIMING xie CHING-HWA HO ZHIYI wei School of Physics and Optoelectronics Engineering Xidian University CAS Key Laboratory of Standardization and Measurement for Nanotechnology CAS Center for Excellence in NanoscienceNational Center for Nanoscience and Technology University of chinese academy of sciences Graduate Institute of applied science and Technology Taiwan University of Science and Technology beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences

We report Q-switched and mode-locked erbium-doped all-fiber lasers using ternary ReS_(2.1-x))Se_(2.) as saturable absorbers(SAs). The modulation depth and saturable intensity of the film SA are 1.8% and 0.046 MW∕*** Q-switched mechanism output, the pulse was centered at 153..1 nm with maximum pulse energy and minimum pulse width of 2..2. nJ and 1.07 μs, respectively. In mode-locked operation, the pulse was centered at1561.15 nm with pulse width of 888 fs, repetition rate of 2.95 MHz, and maximum pulse energy of 0.2.5 nJ. To the best of our knowledge, this is the first report on the mode-locked Er^(3.)-doped fiber laser using ternary transition metal dichalcogenides. This work suggests prospective 2.D-material SAs can be widely used in versatile fields due to their attractive optoelectronic and tunable energy bandgap properties.

关键词： Ternary ReS2.1-x)Se2. alloy saturable absorber mode-locked erbium-doped all-fiber lasers Q-switched

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High-efficiency organic solar cells enabled by an alcohol-washable solid additive

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science china Chemistry 2021年第12期64卷 2161-2168页

作者： Yuanpeng xie Hwa Sook Ryu Lili Han Yunhao Cai Xiaopeng Duan Donghui wei Han Young Woo Yanming Sun School of Chemistry Beihang UniversityBeijing100191China Department of Chemistry College of ScienceKU-KIST Graduate School of Converging Science and TechnologyKorea UniversitySeoul136-713Korea College of Chemistry and Molecular Engineering Zhengzhou UniversityZhengzhou450001China

The solvent additive strategy has been widely utilized to boost the power conversion efficiency(PCE)of organic solar cells(OSCs).However,the residual solvent additive in the active layer tends to induce a gradual morphology degradation and further influences the long-term stability of ***,a solid additive,1,4-diiodobenzene(DIB),was introduced to fabricate efficient *** found that the treatment of DIB can lead to optimized morphology to form a bicontinuous network with intensified intermolecular packing in the donor and acceptor ***,DIB can be easily removed from the active layer via a simple alcohol washing process and no further post-thermal annealing is needed,which is desirable for large-scale manufacturing of *** a result,high efficiencies of 17.47%for PM6:Y6 and 18.13.(certified as 17.7%)for PM6:BTP-eC9 binary OSCs are achieved,which are among the highest efficiencies reported for binary OSCs thus ***,OSCs fabricated with DIB also exhibit superior stability compared with the as-cast and traditional solvent additive processed ***,DIB was successfully applied in different active layers,manifesting its general *** work provides a feasible approach to enhance both the efficiency and stability of OSCs.

关键词： organic solar cells solid additive alcohol washing process efficiency stability

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考虑时间滞后效应的库岸滑坡位移预测

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武汉大学学报（信息科学版） 2024年第8期49卷 1347-1355页

作者：杜岩宁利泽谢谟文白云飞李恒贾北凝北京科技大学城市地下空间工程北京市重点实验室北京100083 建设部综合勘察设计研究院有限公司北京100007

在库区滑坡位移预测预报研究中,库水位响应的滞后性使得传统滑坡位移预测模型难以分析单调增长的阶跃式变形特征,严重影响预测结果。基于此,在考虑库水位时间滞后效应基础上,建立了一套可应用于工程现场的自回归分布滞后位移预测模型,... 详细信息

在库区滑坡位移预测预报研究中,库水位响应的滞后性使得传统滑坡位移预测模型难以分析单调增长的阶跃式变形特征,严重影响预测结果。基于此,在考虑库水位时间滞后效应基础上,建立了一套可应用于工程现场的自回归分布滞后位移预测模型,并在金沙江上游某库岸滑坡进行工程应用。工程研究案例得出,库水位上升、地震是该滑坡变形加剧的主要诱发因素,且库水位作用于滑坡变形的滞后天数为8天,新模型计算滑坡累积位移与实际位移相关系数高达0.992.7,均方根误差为14.11 mm。此外,通过计算趋势速率比指标可以为滑坡监测预警提供新的敏感性评价参量。该研究不仅建立了一套具有物理意义的库岸滑坡位移预测模型,实现了滑坡位移的综合分析,而且实现了地震对滑坡位移演化贡献的定量计算,为蓄水期库岸滑坡演化全过程的安全风险管理提供了新的技术支持。

关键词：滑坡位移预测时间滞后效应自回归分布滞后模型库水位趋势速率比

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A Localization Method of High Energy Transients for All-sky Gamma-ray Monitor

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research in Astronomy and Astrophysics 2024年第10期24卷 25-35页

作者： Yi Zhao Wangchen Xue Shaolin Xiong Qi Luo Yuanhao Wang Jiacong Liu Heng Yu Xiaoyun Zhao Yue Huang Jinyuan Liao Jianchao Sun Xiaobo Li Qibin Yi Ce Cai Shuo Xiao Shenglun xie Chao Zheng Yanqiu Zhang Chenwei Wang Wenjun Tan Zhiwei Guo Chaoyang Li Zhenghua An Gang Chen Yanqi Du Min Gao Ke Gong Dongya Guo Jiang He Jianjian He Bing Li Gang Li Xinqiao Li Jing Liang Xiaohua Liang Yaqing Liu Xiang Ma Rui Qiao Liming Song Xinying Song Xilei Sun Jin Wang Ping Wang Xiangyang Wen Hong Wu Yanbing Xu Sheng Yang Dali Zhang Fan Zhang Hongmei Zhang Peng Zhang Shu Zhang Zhen Zhang Shijie Zheng Keke Zhang Xingbo Han Haiyan Wu Hu Tai Hao Geng Gaopeng Lu wei Xu Fanchao Lyu Hongbo Zhang Fangjun Lu Shuangnan Zhang Department of Astronomy Beijing Normal UniversityBeijing 100875China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of chinese academy of sciences Beijing 100049China School of Physics and Optoelectronics Xiangtan UniversityXiangtan 411105China College of Physics Hebei Normal UniversityShijiazhuang 050024China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550001China School of Physics and Electronic science Guizhou Normal UniversityGuiyang 550001China Institute of Astrophysics Central China Normal UniversityWuhan 430079China College of physics sciences Technology Hebei UniversityBaoding 071002China Physics and space science College China West Normal UniversityNanchong 637002China School of Computing and Artificial Intelligence Southwest Jiaotong UniversityChengdu 611756China College of Electronic and information Engineering Tongji UniversityShanghai 201804China Innovation academy for Microsatellites of chinese academy of sciences Shanghai 201304China National space science {2. Chinese Academy of SciencesBeijing 100190China School of Earth and space sciences University of Science and Technology of ChinaHefei 230026China Electronic Information School Wuhan UniversityWuhan 430072China Key Laboratory of Transportation Meteorology of china Meteorological Administration Nanjing Joint Institute for Atmospheric SciencesNanjing 210000China Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

Fast and reliable localization of high-energy transients is crucial for characterizing the burst properties and guiding the follow-up *** based on the relative counts of different detectors has been widely used for all-sky gamma-ray *** are two major methods for this count distribution localization:χ^(2.minimization method and the Bayesian *** we propose a modified Bayesian method that could take advantage of both the accuracy of the Bayesian method and the simplicity of the χ^(2.*** comprehensive simulations,we find that our Bayesian method with Poisson likelihood is generally more applicable for various bursts than the χ^(2.method,especially for weak *** further proposed a location-spectrum iteration approach based on the Bayesian inference,which could alleviate the problems caused by the spectral difference between the burst and location *** method is very suitable for scenarios with limited computation resources or timesensitive applications,such as in-flight localization software,and low-latency localization for rapidly follow-up observations.

关键词： methods:data analysis methods:analytical (stars:)gamma-ray burst:general

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