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红外自由曲面棱镜的高精度补偿加工方法

光学学报 2024年第13期44卷 213-221页

作者：刘晓天余俊王晓强何春伶王一凡文骁王东方王占山同济大学物理科学与工程学院先进微结构材料教育部重点实验室上海200092 同济大学物理科学与工程学院精密光学工程技术研究所上海200092 中国科学院上海技术物理研究所光电制造工程中心上海200083

为实现自由曲面棱镜的高精度制造,首先分析加工误差对自由曲面棱镜的成像性能影响,根据误差分析设计专用夹具,用于控制各曲面加工的中心位置。然后,提出一种基于在位与离线检测技术相结合的自由曲面棱镜高精度补偿车削加工方法,用以监... 详细信息

为实现自由曲面棱镜的高精度制造,首先分析加工误差对自由曲面棱镜的成像性能影响,根据误差分析设计专用夹具,用于控制各曲面加工的中心位置。然后,提出一种基于在位与离线检测技术相结合的自由曲面棱镜高精度补偿车削加工方法,用以监测在加工过程中各阶段的定位误差量,并将误差量反馈于车削的补偿修正,这种方法极大地提升了自由曲面棱镜的加工精度。最后,对自由曲面棱镜台阶面和自由曲面棱镜分别进行了角度误差分析和成像性能检测,得到自由曲面棱镜台阶面的最大角度加工误差为0.03°,自由曲面棱镜在全视场实际成像效果清晰,证明了所提出的补偿加工方法的精度和可行性。

关键词：光学设计自由曲面棱镜公差分析在位与离线检测高精度补偿

Gini Correlation for Feature Screening

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Acta Mathematicae Applicatae Sinica 2021年第3期37卷 590-601页

作者： jun-ying ZHANG Xiao-feng liu Ri-quan ZHANG Hang-WANG Department of Mathematics Taiyuan University of TechnologyTaiyuan 030024China College of Data Science Taiyuan University of TechnologyTaiyuan 030024China School of Finance and Statistics East China Normal UniversityShanghai 200241China Department of Mathematics Shanxi Datong UniversityDatong 037009China

In this paper we propose the Gini correlation screening(GCS)method to select the important variables with ultrahigh dimensional *** new procedure is based on the Gini correlation coefficient via the covariance between the response and the rank of the predictor variables rather than the Pearson correlation and the Kendallτcorrelation *** new method does not require imposing a specific model structure on regression functions and only needs the condition which the predictors and response have continuous distribution *** demonstrate that,with the number of predictors growing at an exponential rate of the sample size,the proposed procedure possesses consistency in ranking,which is both useful in its own right and can lead to consistency in *** procedure is computationally efficient and simple,and exhibits a competent empirical performance in our intensive simulations and real data analysis.

关键词： ultrahigh dimension Gini correlation coefficient variable screening feature ranking

石羊河流域生态系统碳储量时空变化及多情景模拟

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中国环境科学 2024年第6期44卷 3365-3375页

作者：许澳康胡梦珺石晶孟祥云白清竹郭婧玲刘烁雅张嗣阳西北师范大学地理与环境科学学院甘肃省绿洲资源环境与可持续发展重点实验室甘肃兰州730070

以石羊河流域为例,利用InVEST模型评估1990~2020年土地利用变化带来的碳储量效应,耦合PLUS模型模拟2035年在自然发展、生态保护、水资源约束和经济发展情景下土地利用变化及其对碳储量的影响.结果表明:石羊河流域土地利用主要以未利用地... 详细信息

以石羊河流域为例,利用InVEST模型评估1990~2020年土地利用变化带来的碳储量效应,耦合PLUS模型模拟2035年在自然发展、生态保护、水资源约束和经济发展情景下土地利用变化及其对碳储量的影响.结果表明:石羊河流域土地利用主要以未利用地,草地和耕地为主,占流域总面积的93%.1990~2020年石羊河流域耕地,水域和建设用地面积呈增长趋势,其余用地面积呈减少趋势.2020~2035年多情景模拟下,只有生态情境中林地和草地面积增加显著.1990~2020年流域碳储量整体呈增长趋势,其中以草地,未利用地和耕地碳储量贡献为主,占碳总量的86%.2020~2035年4种情景下的碳储量均有所增加,但生态保护情景中碳储量增加最为显著,共增加3.75×10^(6)t.自然发展情景和经济发展情景下,林地和草地转为耕地的面积远大于转入,碳储量损失较多.水资源约束情景下,耕地主要转出为草地和建设用地,其他各地类之间转换所承载的碳储量基本平衡.生态保护情景下,林地,草地等生态用地转入面积大于转出使区域碳储量增加.研究结果以期为石羊河流域提升陆地生态系统碳储量和规划未来国土空间提供科学依据.

关键词：碳储量 InVEST模型 PLUS模型土地利用石羊河流域

Characterization of localized corrosion pathways in 2195-T8 Al-Li alloys exposed to acidic solution

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Defence Technology（防务技术） 2023年第7期25卷 152-165页

作者： De-jun liu Gan Tian Guo-feng Jin Wei Zhang You-hong Zhang Rocket Force University of Engineering College of Missile EngineeringChina

The corrosion properties of aluminum-lithium(Al-Li) alloys, which are potential materials used to construct for tanks of liquid rockets or missiles, are essential for safe propellant storage and transport. In order to manifest the corrosion resistance of the 2195 Al-Li alloy in practical propellant tanks filled with N2O4, the alloy was soaked in 30% nitric acid solution, an accelerating corrosion environment, to test its corrosion behavior. Scanning electron microscopy(SEM) and transmission electron microscopy(TEM)were used to characterize microstructure and corrosion morphology of the alloy. Focused ion beam(FIB),combined with SEM, was used to demonstrate localized corrosion features and the propagation of corrosion pathways beneath the alloy surface. It was found that the corrosion network was formed with most intergranular corrosion and sparse intragranular corrosion. Additionally, the distribution and number of intermetallic particles influenced the localized corrosion degree and the direction of corrosion pathways. Aggregated particles made corrosion pathways continuously and caused more severe corrosion. The results from this work were valid and useful to corrosion prevention and protection for storage safety on propellant tanks in N_(2)O_(4).

关键词： Al-Li alloy Corrosion behavior Corrosion features Immersion test Intermetallic particles

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黑臭水体沉积物中新型溴代阻燃剂的污染特征

中国环境科学 2024年第7期44卷 3945-3954页

作者：黄晨晨曾艳红管克兰刘银娥鲁祺鸿汪善全罗孝俊麦碧娴中国矿业大学环境与测绘学院江苏徐州221116 中国科学院广州地球化学研究所有机地球化学国家重点实验室与广东省资源环境利用与保护重点实验室广东广州510640 中山大学环境科学与工程学院广东广州510006

测定了中国74个城市的173条黑臭水体沉积物中6种新型溴代阻燃剂(NBFRs)的污染现状.结果表明,十溴二苯乙烷(DBDPE)是沉积物中主要的NBFRs,其浓度范围为未检出~603.76ng/g干重,平均浓度占比高达(99.49±0.82)%;六溴苯(HBB)和五溴甲苯(PBT... 详细信息

测定了中国74个城市的173条黑臭水体沉积物中6种新型溴代阻燃剂(NBFRs)的污染现状.结果表明,十溴二苯乙烷(DBDPE)是沉积物中主要的NBFRs,其浓度范围为未检出~603.76ng/g干重,平均浓度占比高达(99.49±0.82)%;六溴苯(HBB)和五溴甲苯(PBT)占比较低.NBFRs的组成符合其在中国的生产和使用情况.尽管DBDPE、HBB和PBT均在不同城市间具有显著的浓度差异,但是总体呈现东部高(华南、华东和东北地区)、西部低(西北和西南地区)的分布格局,各地区的产业结构和城市化率是控制其空间分布的重要因素.DBDPE作为多溴联苯醚十溴工业品(BDE209)的替代品,其在沉积物中的浓度仍普遍低于BDE209,且DBDPE/BDE209比值与各城市的生产总值和工业产值呈显著的负相关关系.生态风险评价表明黑臭水体沉积物中DBDPE、HBB和PBT均不足以对水生生物造成暴露风险.

关键词：城市黑臭水体表层沉积物新型溴代阻燃剂污染特征生态风险评估

Estimating the maximum impact force of dry granular flow based on pileup characteristics

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Journal of Mountain Science 2019年第10期16卷 2435-2452页

作者： XIAO Si-you SU Li-jun JIANG Yuan-jun MEHTAB Alam LI Cheng liu Dao-chuan Key Laboratory of Mountain Hazards and Earth Surface Processes and Institute of Mountain Hazards andEnvironmentChinese Academy of SciencesChengdu610041China University of Chinese Academy of Sciences Beijing100049China CAS Center for Excellence in Tibetan Plateau Earth Sciences Beijing100101China Sichuan Highway Planning DesignResearch Institute LtdChengdu610041China

The maximum normal impact resultant force(NIRF)is usually regarded as the sum of the static earth pressure of the dead zone and the dynamic impact pressure of the flowing *** influence of the interaction between the flowing layer and dead zone on the impact force is *** this study,we classified two impact models with respect to the pileup characteristics of the dead ***,we employed the discrete element method to investigate the influences of the pileup characteristics on the impact force of dry granular flow on a tilted rigid *** the final pileup height is equal to the critical value,the maximum NIRF can be estimated using a hydrostatic model,because the main contribution to the maximum NIRF is the static earth pressure of the dead *** the final pileup height is less than the critical value,however,the particles in the dead zone are squeezed along the slope surface by the impact ofthe flowing layer on the dead zone,and because of shear effects,the flowing layer causes an entrainment in the dead *** results in a decrease in the volume of the dead zone at the moment of maximum NIRF with increases in the slope *** such,the maximum NIRF mainly comprises the instant impact force of the flowing layer,so hydro-dynamic models are effective for estimating the maximum *** models will benefit from further study of the components and distribution of the impact force of dry granular flow.

关键词： Dry granular flow Tilted retaining wall Impact force Discrete element method Pileup height

In-situ nanoscale insights into the evolution of solid electrolyte interphase shells:revealing interfacial degradation in lithium metal batteries

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Science China Chemistry 2021年第5期64卷 734-738页

作者： Yang Shi Gui-Xian liu Jing Wan Rui Wen Li-jun Wan Key Laboratory of Molecular Nanostructure and Nanotechnology Beijing National Laboratory for Molecular SciencesCAS Research/Education Center for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of the Chinese Academy of Sciences Beijing 100049China

The solid electrolyte interphase(SEI)has caught considerable attention as a pivotal factor affecting lithium(Li)metal battery ***,the understanding of the interfacial evolution and properties of the on-site formed SEI shells on Li deposits during cycling is still at a preliminary ***,we provide a straightforward visualized evidence of SEI shells’evolution during Li deposition/stripping to reveal anode degradation via in-situ atomic force microscopy(AFM).Nucleation and growth of quasi-spherical Li particles are observed on a Cu substrate,followed by Li stripping and collapse of SEI *** the subsequent cycling,new Li deposits tend to nucleate at pristine sites with fresh SEI shells forming on *** previously collapsed SEI shells accumulate to increase interface impedance,eventually leading to capacity *** the electrochemical processes and interfacial degradation at the nanoscale will enrich fundamental comprehension and further guide improvement strategies of Li metal anodes.

关键词： solid electrolyte interphase shell lithium deposition and stripping interfacial degradation lithium metal battery

Mining Design Pattern Use Scenarios and Related Design Pattern Pairs:A Case Study on Online Posts

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Journal of Computer Science & Technology 2020年第5期35卷 963-978页

作者： Dong liu Zhi-Lei Ren Zhong-Tian Long Guo-jun Gao He Jiang School of Software Dalian University of TechnologyDalian 116024China Key Laboratory for Ubiquitous Network and Service Software of Liaoning Province Dalian 116000China DUT-RU International School of Information Science&Engineering at DUT Dalian University of Technology Dalian 116620China

In common design pattern collections,e.g.,design pattern books,design patterns are documented with templates that consist of multiple attributes,such as intent,structure,and sample *** adapt to modern developers,the depictions of design patterns,especially some specific attributes,should advance with the current programming technologies,for example,“known uses”,which exemplifies the use scenarios of design patterns in practice,and“related patterns”,which describes the relatedness between a design pattern and the others within a ***,it is not easy to update the contents of these attributes manually due to the diversity of the programming *** address this problem,in this work,we conducted a case study to mine design pattern use scenarios and related design pattern pairs from Stack Overflow posts to enrich the two *** first extracted the question posts relevant to each design pattern by identifying the design pattern ***,the topics of the posts were discovered by applying topic modeling ***,by analyzing the topics specified for each design pattern,we detected 195 design pattern use scenarios and 70 related design pattern pairs,involving 61 design patterns *** findings are associated with a variety of popular software frameworks and programming *** could complement the existing design pattern collections and help developers better acknowledge the usage and relatedness of design patterns in today's programming practice.

关键词： design pattern software documentation Stack Overflow topic model

Effect of Annealing Time on Microstructure and Mechanical Properties of Cold-Rolled Niobium and Titanium Bearing Micro-alloyed Steel Strips

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Journal of Iron and Steel Research International 2013年第9期20卷 86-92页

作者： CHEN jun SHEN Xin-jun JI Feng-qin TANG Shuai liu Zhen-yu WANG Guo-dong State Key Laboratory of Rolling and Automation Northeastern University

Effects of annealing time on microstructure of cold-roiled niobium-titanium bearing micro-alloyed steel strips were investigated by optical microscopy, scanning electron microscopy, electron back-scatter diffraction （EBSD） and transmission electron microscopy. The complete recrystallization annealing temperature of 670 ℃ and complete annealing time of 9 min were determined using Vickers-hardness testing and EBSD analysis. The ferrite mi-crostructure with spheric cementite particles and nano-scale precipitates of Nb（C,N） in matrix was obtained. The ki-netics of the ferrite grain growth is lowered due to ferrite grain boundaries pinned by the cementite particles, so the ferrite grain size of 5.5 μm remains unchanged among the annealing time ranging from 9 to 30 min. In addition, the strength of tested steel also keeps unchanged with the increase of annealing time. The higher yield strength of ap-proximately 420 MPa can be obtained by grain refinement and precipitation hardening and the higher elongation of approximately 40% and work-hardening exponent of approximately 0.2 can be gained due to grain refinement and presence of cementite particles, indicating that the balance of strength, ductility and forming property is realized.

关键词： Nb-Ti bearing micro-alloyed steel cold rolling annealing microstructure mechanical property