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镁合金表面DCPD涂层的制备及其界面结合机制研究

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表面技术 2024年第4期53卷 193-199,210页

作者：李沛李志杨建成袁静青海省人民医院骨科二病区西宁810007 青海民族大学物理与电子信息工程学院西宁810007

目的研究CaHPO_(4)·2H_(2)O(DCPD)与Mg的界面结合机制,以提高DCPD在镁合金表面的界面结合强度。方法利用电镀法在AZ31镁合金表面制备DCPD涂层,采用SEM、XRD、XPS等对涂层形貌及结构进行表征。同时,运用分子动力学模拟(MD)对DCPD在Mg表... 详细信息

目的研究CaHPO_(4)·2H_(2)O(DCPD)与Mg的界面结合机制,以提高DCPD在镁合金表面的界面结合强度。方法利用电镀法在AZ31镁合金表面制备DCPD涂层,采用SEM、XRD、XPS等对涂层形貌及结构进行表征。同时,运用分子动力学模拟(MD)对DCPD在Mg表面形成机制进行研究,通过统计界面层中不同组分的径向分布函数、密度分布、均力势、总能量等的变化,揭示DCPD/Mg的界面结合能、结合位点及结合方式。结果通过电镀法形成的DCPD涂层形貌为致密的荷花瓣状晶体,主要成分为CaHPO_(4)·2H_(2)O。模拟结果表明,CaHPO_(4)·2H_(2)O的4个晶面(010)、(-120)、(11-1)、(111)、(-120)与Mg的结合能最强(163.63 kJ/mol)。其中起“铆钉”作用的基团是HPO_(4)^(2-)和H_(2)O,结合位点主要为O与Mg,即HPO_(4)^(2-)和H_(2)O通过静电作用及范德华力与Mg形成Mg-HPO_(4)^(2-)和Mg-H_(2)O偶极对。研究发现,形成的偶极对中HPO_(4)^(2-)及H_(2)O的配位数分别为0.75和1.16,Mg-H_(2)O的解离能更大,结构更稳定。结论提出改善DCPD/Mg结合强度的方法,电镀前可将镁合金置于NH4H_(2)PO_(4)溶液中浸泡片刻,促进CaHPO_(4)·2H_(2)O(-120)晶面的形成。

关键词：镁合金 DCPD涂层界面结合能界面结合位点分子动力学模拟

Emission control strategies of hazardous trace elements from coal-fired power plants in China

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Journal of Environmental Sciences 2020年第7期32卷 66-90页

作者： Adwek George Boxiong Shen Dongrui Kang jiancheng yang Jiangze Luo School of Energy and Environmental Engineering Tianjin Key Laboratory of Clean Energy Utilization and Pollution ControlHebei University of TechnologyTianjinChina Department of Energy and Environmental Engineering Mount Kenya UniversityThika-Kenya

China’s energy dependents on coal due to the abundance and low cost of *** provides a secure and stable energy source in ***-dependence on coal results in the emission of Hazardous Trace Elements(HTEs)including selenium(Se),mercury(Hg),lead(Pb),arsenic(As),etc.,from Coal-Fired Power Plants(CFPPs),which are the major toxic air pollutants causing widespread *** this reason,it is essential to provide a succinct analysis of the main HTEs emission control techniques while concurrently identifying the research prospects framework and specifying future research *** study herein reviews various techniques applied in China for the selected HTEs emission control,including the technical,institutional,policy,and regulatory *** specific areas covered in this study include health effects,future coal production and consumption,the current situation of HTEs in Chinese coal,the chemistry of selected HTEs,control techniques,policies,and action plans safeguarding the emission *** review emphasizes the fact that China must establish and promote efficient and clean ways to utilize coal in order to realize sustainable *** principal conclusion is that cleaning coal technologies and fuel substitution should be great potential HTEs control technologies in *** research should focus on the simultaneous removal of HTEs,PM,SOx,and NOx in the complex flue gas.

关键词： Coal Coal-fired power plants Policies Heavy trace elements

间隔织物双剑杆织机平行打纬机构箱体的振动分析

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天津工业大学学报 2024年第3期43卷 82-88页

作者：杨建成刘艳哲黄子文赵全鹏刘健天津工业大学机械工程学院天津300387 天津工业大学天津市现代机电装备技术重点实验室天津300387 天津工业大学天津市机械基础及纺织装备设计虚拟仿真实验教学中心天津300387

针对双剑杆织机共轭凸轮与四连杆组合的平行打纬机构箱体随着织机转速的提高产生强烈振动,影响打纬精度和可靠性的问题,采用理论分析与虚拟仿真结合的方法对打纬机构及箱体进行动应力和振动特性研究。建立了平行打纬机构的动态静力分析... 详细信息

针对双剑杆织机共轭凸轮与四连杆组合的平行打纬机构箱体随着织机转速的提高产生强烈振动,影响打纬精度和可靠性的问题,采用理论分析与虚拟仿真结合的方法对打纬机构及箱体进行动应力和振动特性研究。建立了平行打纬机构的动态静力分析方程,运用ADAMS软件对机构进行多体动力学仿真,求解箱体所受的支反力;构建箱体—弹簧阻尼—柔性基础的系统模型,分析箱体在竖直方向的受迫振动,并在仿真过程中探索减小箱体振动的方法。研究结果表明:摆臂轴孔处箱体所受支反力峰值最大,打纬推程阶段箱体的受力最为集中;当凸轮轴转速为260 r/min时齿轮啮合频率与箱体一阶固有频率相等,会产生共振,应避免使用这一转速工作;箱体在竖直方向上产生周期性振动,增加螺栓个数和附加动力减震器有助于改善箱体的振动特性,振幅分别减少38%和23%。

关键词：双剑杆织机平行打纬机构支反力动态静力分析弹簧阻尼减振

Investigation on the urea deposit formation and thermal decomposition characteristics in the SCR aftertreatment system of a diesel engine

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Journal of Environmental Sciences 2021年第5期33卷 157-171页

作者： Menghan Li Yao Zhang jiancheng yang Xiaori Liu Zhenguo Li Qiang Zhang Tianjin Key Laboratory of Clean Energy and Pollution Control School of Energy and Environmental EngineeringHebei University of TechnologyTianjin 300401China School of Civil and Transportation Engineering Hebei University of TechnologyTianjin 300401China National Engineering Laboratory for Mobile Source Emission Control Technology China Automotive Technology&Research Center Co.Ltd.Tianjin 300300China State Key Laboratory of Engines Tianjin UniversityTianjin 300072China School of Energy and Power Engineering Shandong UniversityJinanShandong 250061China

Selective catalytic reduction is the most efficient and reliable equipment for NOx control in current diesel engines. However, the issue of urea crystallization becomes increasingly serious with the implement of the new emissions standards. In this paper, urea deposit samples collected from engine test bed and tube furnace were characterized by thermogravimetric analysis and Fourier transform-infrared analysis to aid the comprehension of urea deposit formation. Moreover, thermogravimetric tests were conducted to disclose the effects of catalyst on the thermal decomposition processes of urea deposit. The results indicated that less temperature resistant species are formed in the engine test bed than in the tube furnace at conditions with the same temperatures. The main compositions in the World Harmonized Transient Cycle(WHTC) urea deposits are urea, cyanuric acid(CYA) and ammelide, implying that accelerating the decomposition of these species could prevent the accumulation of urea deposit. CuWTi, Cu β and CuZSM catalysts could lead to increased yield of CYA during pure urea thermolysis. Cu β, CuWTi and VWTi catalysts tend to promote the thermolysis of CYA while VWTi has the most significant catalytic effects on the thermal decomposition of ammelide and ammeline.

关键词： Urea deposit Decomposition characteristics Selective catalytic reduction Catalyst Thermolysis

考虑能源低碳化的分区域虚拟电厂综合优化调度策略

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电力勘测设计 2024年第8期 21-28页

作者：刘晓鸥李伟黄晶晶杨建成中国电力工程顾问集团有限公司北京100101

为实现虚拟电厂内多个分布式能源系统的优化协同调度,本文提出考虑能源低碳化的分区域虚拟电厂综合优化调度策略。首先,搭建多区域虚拟电厂结构图,可通过各综合能源系统的互联互通实现区域间的电能互补。然后,搭建P2G复合系统模型,通过... 详细信息

为实现虚拟电厂内多个分布式能源系统的优化协同调度,本文提出考虑能源低碳化的分区域虚拟电厂综合优化调度策略。首先,搭建多区域虚拟电厂结构图,可通过各综合能源系统的互联互通实现区域间的电能互补。然后,搭建P2G复合系统模型,通过聚合碳捕集电厂、电制气、粪污处理、热电联产机组和燃气锅炉实现联合运行,提升可再生能源的消纳能力,以达到运行效益最大化的目标。针对复合微分进化算法的不足,提出改进措施以求解高维非线性目标函数模型。最后,通过算例仿真验证了本文方法的有效性。本文所提方法可实现多区域间的电能和热能协同优化调度,提升可再生能源消纳能力,改善虚拟电厂运行效益和碳排放量。

关键词：虚拟电厂能源互补低碳化多区域优化调度

Information-Theoretic Limits on Compression of Semantic Information

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China Communications 2024年第7期21卷 1-16页

作者： Tang jiancheng yang Qianqian Zhang Zhaoyang College of Information Science and Electronic Engineering Zhejiang UniversityHangzhou 310007China

As conventional communication systems based on classic information theory have closely approached Shannon capacity,semantic communication is emerging as a key enabling technology for the further improvement of communication ***,it is still unsettled on how to represent semantic information and characterise the theoretical limits of semantic-oriented compression and *** this paper,we consider a semantic source which is characterised by a set of correlated random variables whose joint probabilistic distribution can be described by a Bayesian *** give the information-theoretic limit on the lossless compression of the semantic source and introduce a low complexity encoding method by exploiting the conditional *** further characterise the limits on lossy compression of the semantic source and the upper and lower bounds of the rate-distortion *** also investigate the lossy compression of the semantic source with two-sided information at the encoder and decoder,and obtain the corresponding rate distortion *** prove that the optimal code of the semantic source is the combination of the optimal codes of each conditional independent set given the side information.

关键词： rate distortion semantic communication semantic compression

胎方位异常阴道分娩第二产程会阴超声测量产程进展参数的临床研究

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现代妇产科进展 2024年第9期33卷 656-661页

作者：杨建成马琰徐颖施梦蝶邹小君邱剑萍南京医科大学附属苏州医院妇产科苏州215008

目的:研究评价会阴超声监测产程进展参数在评估胎方位异常(枕后位或枕横位)阴道分娩管理中的有效性及临床应用。方法:收集2021年6月至2023年6月于南京医科大学附属苏州医院妇产科足月妊娠胎方位异常产妇阴道试产第二产程达2h以上48例。... 详细信息

目的:研究评价会阴超声监测产程进展参数在评估胎方位异常(枕后位或枕横位)阴道分娩管理中的有效性及临床应用。方法:收集2021年6月至2023年6月于南京医科大学附属苏州医院妇产科足月妊娠胎方位异常产妇阴道试产第二产程达2h以上48例。根据分娩方式分为阴道分娩组(35例,A组)和中转剖宫产组(13例,B组)。产程中通过会阴超声测量第二产程不同时间点关键产程进展角(AOP)和中线角(MA)等评估产程进展。比较两组产程AOP及MA等。采用logistic回归分析相关危险因素,采用ROC曲线分析并计算截断值。结果:胎方位异常第二产程宫口开全时,阴道分娩组和中转剖宫产组的AOP平均值分别为(127.5±4.5)°、(107.5±6.6)°;宫口开全1h,AOP平均值分别为(135.3±3.9)°、(114.0±7.8)°;宫口开全2h时,AOP平均值分别为(157.7±5.6)°、(125.3±5.3)°。胎方位异常在第二产程宫口开全时,阴道分娩组和中转剖宫产组的MA平均值为(112.7±18.7)°、(137.2±19.5)°;宫口开全1h,MA平均值分别为(73.9±18.0)°、(128.0±18.9)°;宫口开全2h,MA平均值分别为(28.1±8.1)°、(118.2±16.4)°。两组三个时间点AOP及MA比较,差异均有统计学意义(P<0.05)。Logistic回归分析显示,胎儿体重是影响分娩结局的最大危险因素。ROC曲线提示AOP诊断价值优于MA。根据ROC曲线计算出0、1、2h AOP的截断值分别为118°、129°、142°,0、1、2h MA的截断值分别为94°、74°、45°。结论:通过会阴超声测量产程进展参数AOP及中线角MA,可准确有效评估胎方位异常阴道分娩产程进展,减少产妇阴道指检痛苦及感染风险,及时干预产程,避免母婴分娩严重并发症发生。

关键词：产程进展参数胎方位异常会阴超声产程进展角中线角

Multi-path navigation method using solar panel-reflected solar oscillations for Earth satellites

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Science China(Information Sciences) 2024年第7期67卷 327-328页

作者： Yuqing yang Haonan yang Xiaolin NING Weiren WU jiancheng FANG School of Instrument Science & Opto-electronics Engineering Beihang University Lunar Exploration and Space Program Center China National Space Administration

Several autonomous navigation methods have been studied to reduce reliance on the ground stations. Geomagnetic navigation, gravity gradient navigation, and celestial navigation using optical sensors are typical autonomous navigation methods. Geomagnetic and gravity gradient navigation have low navigation accuracy (1301 m [1] and 235 m [2], respectively) due to the poor accuracy of the geomagnetic and gravity gradient maps.

关键词： Solar panels

Numerical investigation and modeling of sweep effects on inlet flow field of axial compressor cascades

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Chinese Journal of Aeronautics 2024年第2期37卷 296-308页

作者： jiancheng ZHANG Donghai JIN Xingmin GUI School of Energy and Power Engineering Beihang UniversityBeijing 100191China Jiangxi Research Institue of Beihang University Nanchang 330096China

Swept blades are widely utilized in transonic compressors/fans and provide high load,high through-flow,high efficiency,and adequate stall ***,there is limited quantitative research on the mechanism of the effect of swept blades on the flow field,resulting in a lack of direct quantitative guidance for the design and analysis of swept blades in fans/*** better understand this mechanism,this study employs a reduced-dimensional force equilibrium method to analyze more than 1500 swept cascades *** verify that circumferential fluctuation terms are responsible for inducing radial migration in the inlet airflow field of the swept blade,resulting in variations in the incidence angle and consequently leading to changes in the characteristics of the swept ***,a combination of simple functions and machine learning is utilized to model the circumferential fluctuation terms and quantify the sweep *** prediction accuracy of the model is high,with coefficient of determination greater than 0.95 on the test *** the model is applied in a meridional flow analysis program,the calculation accuracy of the program for the incidence angle is improved by 0.4°and 0.6°at the design and off-design conditions respectively,compensating for the program’s original ***,the model can also provide quantitative guidance for the design of swept blades,thereby reducing the number of design iterations and improving design efficiency.

关键词： Turbomachinery Sweep aerodynamics Quasi-3D method Incidence angle Circumferential fluctuation Machine learning