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帕米尔高原及邻区上地幔顶部Pn波速度和各向异性联合成像
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作者 刘嘉鑫 裴顺平 郭一村 《地震地质》 北大核心 2025年第2期547-560,共14页
帕米尔高原位于印度-欧亚碰撞带西端,研究帕米尔高原及其周边地区的上地幔的速度和各向异性结构对于认识陆-陆碰撞的构造变形特征及动力学机制具有重要意义。Pn波的射线路径集中在上地幔顶部,其横向速度变化能够显示上地幔构造活动差异... 帕米尔高原位于印度-欧亚碰撞带西端,研究帕米尔高原及其周边地区的上地幔的速度和各向异性结构对于认识陆-陆碰撞的构造变形特征及动力学机制具有重要意义。Pn波的射线路径集中在上地幔顶部,其横向速度变化能够显示上地幔构造活动差异,而其方位各向异性结构则能够显示出地幔物质的运动及形变特征。文中利用363 414个Pn波到时数据,通过对Pn波到时进行层析成像,获得了帕米尔高原及其邻近区域上地幔顶部的高分辨率地震波速度和各向异性图像。层析成像结果与地质构造显示出明显的相关性,主要结果表明:1)帕米尔高原、天山、兴都库什、西昆仑、阿尔金山等构造活动区的Pn波速较低,而印度板块、塔里木盆地、塔吉克盆地、准噶尔盆地、费尔干纳盆地等古老稳定地块显示出高Pn波速度特征。2)印度-欧亚板块碰撞产生较强的Pn波各向异性,在帕米尔高原碰撞区两侧的印度板块、塔里木盆地和塔吉克盆地,各向异性方向与板块运动方向一致,而在碰撞区的中间部位,各向异性方向与最大压应力方向及地壳相对运动方向几乎垂直,可能是由于碰撞带上地幔的纯剪切变形所致。天山两侧也存在类似的特征。 展开更多
关键词 帕米尔高原 上地幔顶部 pn 速度和各向异性
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AnMBR-PN/A处理甲胺废水工况优化及能耗评价
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作者 邓萱 陈松 +6 位作者 赵鹤翔 杜博文 杨俞 付静薇 李倩 李玉友 陈荣 《中国环境科学》 北大核心 2025年第10期5517-5524,共8页
构建了厌氧膜生物反应器-部分硝化/厌氧氨氧化(AnMBR-PN/A)系统,研究其处理甲胺废水的工况并对实验效果与能耗、碳排进行评价.研究表明,AnMBR处理甲胺废水的最佳工况HRT为8h,PN/A段HRT为9h时,AnMBR-PN/A体系COD去除率超95%,总氮去除率超... 构建了厌氧膜生物反应器-部分硝化/厌氧氨氧化(AnMBR-PN/A)系统,研究其处理甲胺废水的工况并对实验效果与能耗、碳排进行评价.研究表明,AnMBR处理甲胺废水的最佳工况HRT为8h,PN/A段HRT为9h时,AnMBR-PN/A体系COD去除率超95%,总氮去除率超86%,出水氨氮浓度低于5mg/L,总氮浓度低于15mg/L,达到一级A标准.在最优工况下使用经验公式对体系的能耗和CO_(2)排放进行计算评估,与A^(2)/O工艺相比,AnMBR-PN/A的净能量潜力为0.72,实现了部分能量的回收再利用,同时,AnMBR-PN/A产生的能源气体还具有显著的经济效益.综上,AnMBR-PN/A工艺具有节能减排与降低污水处理成本等多重优势,为实现环境与经济效益的双赢提供了有力支持. 展开更多
关键词 厌氧膜生物反应器 部分硝化/厌氧氨氧化 甲胺废水 物料衡算 能耗分析
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城市污水PN/A工艺中NOB抑制的挑战与对策研究进展
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作者 任核葶 刘浩杰 《工业水处理》 北大核心 2025年第5期38-46,共9页
短程硝化-厌氧氨氧化(PN/A)工艺因节省曝气能耗、无需外加碳源及污泥产量少等优势,成为城市污水生物脱氮工艺的研究热点。城市污水低温、低氨氮的特性使得PN/A工艺中亚硝酸盐氧化菌(NOB)活性抑制困难,进而影响PN/A系统的脱氮效能及稳定... 短程硝化-厌氧氨氧化(PN/A)工艺因节省曝气能耗、无需外加碳源及污泥产量少等优势,成为城市污水生物脱氮工艺的研究热点。城市污水低温、低氨氮的特性使得PN/A工艺中亚硝酸盐氧化菌(NOB)活性抑制困难,进而影响PN/A系统的脱氮效能及稳定性。综述了城市污水PN/A工艺中NOB抑制的挑战及对应解决策略,包括曝气控制、基于生物膜及颗粒污泥的污泥龄(SRT)控制、基于游离氨(FA)/游离亚硝酸(FNA)的NOB活性抑制、强化氨氧化菌(AOB)和厌氧氨氧化菌(AnAOB)活性,以及多种抑制策略联合等。为助力主流PN/A工艺运行调控提供了新思路,并指出深化基础理论研究、开发新型组合工艺强化对NOB的抑制以及提升脱氮性能的稳定性是未来的发展方向。 展开更多
关键词 城市污水 短程硝化-厌氧氨氧化工艺 亚硝酸盐氧化菌抑制 氨氧化菌 亚硝酸盐积累
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Multi-objective optimization of grinding process parameters for improving gear machining precision 被引量:1
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作者 YOU Tong-fei HAN Jiang +4 位作者 TIAN Xiao-qing TANG Jian-ping LU Yi-guo LI Guang-hui XIA Lian 《Journal of Central South University》 2025年第2期538-551,共14页
The gears of new energy vehicles are required to withstand higher rotational speeds and greater loads,which puts forward higher precision essentials for gear manufacturing.However,machining process parameters can caus... The gears of new energy vehicles are required to withstand higher rotational speeds and greater loads,which puts forward higher precision essentials for gear manufacturing.However,machining process parameters can cause changes in cutting force/heat,resulting in affecting gear machining precision.Therefore,this paper studies the effect of different process parameters on gear machining precision.A multi-objective optimization model is established for the relationship between process parameters and tooth surface deviations,tooth profile deviations,and tooth lead deviations through the cutting speed,feed rate,and cutting depth of the worm wheel gear grinding machine.The response surface method(RSM)is used for experimental design,and the corresponding experimental results and optimal process parameters are obtained.Subsequently,gray relational analysis-principal component analysis(GRA-PCA),particle swarm optimization(PSO),and genetic algorithm-particle swarm optimization(GA-PSO)methods are used to analyze the experimental results and obtain different optimal process parameters.The results show that optimal process parameters obtained by the GRA-PCA,PSO,and GA-PSO methods improve the gear machining precision.Moreover,the gear machining precision obtained by GA-PSO is superior to other methods. 展开更多
关键词 worm wheel gear grinding machine gear machining precision machining process parameters multi objective optimization
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一种基于对称PN码设计的时间同步系统及Simulink仿真
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作者 杨鹏 郗波 张恒 《无线电通信技术》 北大核心 2025年第4期870-876,共7页
针对无线通信系统易受噪声干扰导致时间同步不准,接收性能较差的问题,提出了一种基于对称伪噪声(Pseudo-Noise,PN)码设计的时间同步系统,应用Simulink软件完成通信全链路仿真设计。基于伪随机序列(PN码)的自相关特性提出了极性对称的PN... 针对无线通信系统易受噪声干扰导致时间同步不准,接收性能较差的问题,提出了一种基于对称伪噪声(Pseudo-Noise,PN)码设计的时间同步系统,应用Simulink软件完成通信全链路仿真设计。基于伪随机序列(PN码)的自相关特性提出了极性对称的PN码,设计了基于对称PN码的Simulink时间同步系统,以8PSK为调制解调方式,仿真了波形生成、最佳采样、符号同步、数据解调等全链路通信过程。系统基于PN码对称特性提出了增强型滑窗定位算法以提高自相关峰幅值,降低噪声干扰导致的同步字误捕获概率。仿真结果表明,在同等噪声干扰条件下,相比于单极性PN码和Walsh码设计方式,所提时间同步系统具有更高的帧同步准确率,接收端误码率性能具有2 dB以上的显著提升。 展开更多
关键词 对称伪噪声码 同步 最佳采样 8PSK SIMULINK仿真
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Call for Papers from Agricultural Products Processing and Storage
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《食品科学》 北大核心 2025年第20期I0022-I0022,共1页
Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim ... Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim to offer a platform for the rapid dissemination of signifi cant,novel,and high-impact research in the fi elds of agricultural product processing science,technology,engineering,and nutrition.Additionally,supplemental issues are curated and published to facilitate in-depth discussions on special topics. 展开更多
关键词 NUTRITION SCIENCE agricultural products open access journal agricultural products processing STORAGE technology engineering
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Call for Papers from Agricultural Products Processing and Storage
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《肉类研究》 北大核心 2025年第11期I0017-I0017,共1页
Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim ... Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim to offer a platform for the rapid dissemination of signifi cant,novel,and high-impact research in the fi elds of agricultural product processing science,technology,engineering,and nutrition.Additionally,supplemental issues are curated and published to facilitate in-depth discussions on special topics. 展开更多
关键词 NUTRITION SCIENCE agricultural products open access journal agricultural products processing STORAGE technology engineering
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Call for Papers from Agricultural Products Processing and Storage
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《肉类研究》 北大核心 2025年第10期I0017-I0017,共1页
Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim ... Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim to offer a platform for the rapid dissemination of signifi cant,novel,and high-impact research in the fi elds of agricultural product processing science,technology,engineering,and nutrition.Additionally,supplemental issues are curated and published to facilitate in-depth discussions on special topics. 展开更多
关键词 NUTRITION SCIENCE agricultural products open access journal agricultural products processing STORAGE technology engineering
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Call for Papers from Agricultural Products Processing and Storage
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《肉类研究》 北大核心 2025年第9期I0017-I0017,共1页
Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim ... Agricultural Products Processing and Storage(ISSN 3059-4510,Owner:Hunan Academy of Agricultural Sciences,China.Production and hosting:Springer Nature)is an international,peer-reviewed open access journal with the aim to offer a platform for the rapid dissemination of signifi cant,novel,and high-impact research in the fi elds of agricultural product processing science,technology,engineering,and nutrition.Additionally,supplemental issues are curated and published to facilitate in-depth discussions on special topics. 展开更多
关键词 NUTRITION SCIENCE agricultural products open access journal agricultural products processing STORAGE technology engineering
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Enhanced oxidation mechanism of arsenopyrite in two-stage oxidation process applying bio-oxidation waste solution
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作者 ZHANG Shi-qi YANG Hong-ying +3 位作者 TONG Lin-lin CHEN Guo-min KANG Guo-ai ZHAO Zhi-xin 《Journal of Central South University》 2025年第1期94-105,共12页
Applying bio-oxidation waste solution(BOS)to chemical-biological two-stage oxidation process can significantly improve the bio-oxidation efficiency of arsenopyrite.This study aims to clarify the enhanced oxidation mec... Applying bio-oxidation waste solution(BOS)to chemical-biological two-stage oxidation process can significantly improve the bio-oxidation efficiency of arsenopyrite.This study aims to clarify the enhanced oxidation mechanism of arsenopyrite by evaluating the effects of physical and chemical changes of arsenopyrite in BOS chemical oxidation stage on mineral dissolution kinetics,as well as microbial growth activity and community structure composition in bio-oxidation stage.The results showed that the chemical oxidation contributed to destroying the physical and chemical structure of arsenopyrite surface and reducing the particle size,and led to the formation of nitrogenous substances on mineral surface.These chemical oxidation behaviors effectively promoted Fe^(3+)cycling in the bio-oxidation system and weakened the inhibitory effect of the sulfur film on ionic diffusion,thereby enhancing the dissolution kinetics of the arsenopyrite.Therefore,the bio-oxidation efficiency of arsenopyrite was significantly increased in the two-stage oxidation process.After 18 d,the two-stage oxidation process achieved total extraction rates of(88.8±2.0)%,(86.7±1.3)%,and(74.7±3.0)%for As,Fe,and S elements,respectively.These values represented a significant increase of(50.8±3.4)%,(47.1±2.7)%,and(46.0±0.7)%,respectively,compared to the one-stage bio-oxidation process. 展开更多
关键词 BIO-OXIDATION ARSENOPYRITE two-stage oxidation process microbial community kinetics
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Numerical investigation on the engraving process of a pyrotechnic actuator with an improved two-phase flow model of interior ballistic
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作者 Yue Li Cong Liu +1 位作者 Cheng Cheng Genghui Jiang 《Defence Technology(防务技术)》 2025年第4期120-132,共13页
By combining with an improved model on engraving process,a two-phase flow interior ballistic model has been proposed to accurately predict the flow and energy conversion behaviors of pyrotechnic actuators.Using comput... By combining with an improved model on engraving process,a two-phase flow interior ballistic model has been proposed to accurately predict the flow and energy conversion behaviors of pyrotechnic actuators.Using computational fluid dynamics(CFD),the two-phase flow and piston engraving characteristics of a pyrotechnic actuator are investigated.Initially,the current model was utilized to examine the intricate,multi-dimensional flow,and energy conversion characteristics of the propellant grains and combustion gas within the pyrotechnic actuator chamber.It was discovered that the combustion gas on the wall's constant transition from potential to kinetic energy,along with the combined effect of the propellant motion,are what create the pressure oscillation within the chamber.Additionally,a numerical analysis was conducted to determine the impact of various parameters on the pressure oscillation and piston motion,including pyrotechnic charge,pyrotechnic particle size,and chamber structural dimension.The findings show that decreasing the pyrotechnic charge will lower the terminal velocity,while increasing and decreasing the pyrotechnic particle size will reduce the pressure oscillation in the chamber.The pyrotechnic particle size has minimal bearing on the terminal velocity.The results of this investigation offer a trustworthy forecasting instrument for comprehending and creating pyrotechnic actuator designs. 展开更多
关键词 Pyrotechnic actuator Engraving process Two-phase flow Pressure oscillation
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Evaluation of high voltage pulse discharge in resource processing applications:A review
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作者 ZHANG Hong-hao YUAN Shuai +3 位作者 GAO Peng LI Yan-jun HAN Yue-xin DING Hao-yuan 《Journal of Central South University》 2025年第3期934-961,共28页
Breakage is an important step in the resource processing chain.However,the mechanical crushing methods commonly used today suffer from low energy efficiency and high dust levels.Promoting environmental protection and ... Breakage is an important step in the resource processing chain.However,the mechanical crushing methods commonly used today suffer from low energy efficiency and high dust levels.Promoting environmental protection and improving energy efficiency are crucial to advancing China’s circular economy.Mining companies are actively exploring novel and innovative technologies to significantly cut down on operating costs and minimize emissions of dust and pollutants generated during processing.Recently,high voltage pulse discharge(HVPD)technology has received widespread attention and has been reported to have good application prospects in resource processing.This paper presents an extensive review of the operational principles of HVPD and the unique characteristics it engenders,such as non-polluting,selective material fragmentation,pre-weakening,pre-concentration,and enhanced permeability of coal seams.Additionally,this review explores the potential and obstacles confronting HVPD in industrial contexts,offering fresh insights for HVPD optimization and providing guidance and prospects for industrial deployment and further development. 展开更多
关键词 resource processing high voltage pulse discharge selective fragmentation pre-weakening PRE-CONCENTRATION
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Intensive processing optimization of Zn-Cu fabricated by laser powder-bed fusion
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作者 YAN Yi-cheng ZHU Jiang-qi +9 位作者 YAN Yuan-ming LIU Yang LIU Ya-jun SHI Chun-bao LIU Yong LIU Min QIU Hao HUANG Qian-li YAN Xing-chen ZHANG Xiang-yu 《Journal of Central South University》 2025年第4期1194-1210,共17页
Laser powder-bed fusion(LPBF)of Zn-0.8Cu(wt.%)alloys exhibits significant advantages in the customization of biodegradable bone implants.However,the formability of LPBFed Zn alloy is not sufficient due to the spheroid... Laser powder-bed fusion(LPBF)of Zn-0.8Cu(wt.%)alloys exhibits significant advantages in the customization of biodegradable bone implants.However,the formability of LPBFed Zn alloy is not sufficient due to the spheroidization during the interaction of powder and laser beam,of which the mechanism is still not well understood.In this study,the evolution of morphology and grain structure of the LPBFed Zn-Cu alloy was investigated based on single-track deposition experiments.As the scanning speed increases,the grain structure of a single track of Zn-Cu alloy gradually refines,but the formability deteriorates,leading to the defect’s formation in the subsequent fabrication.The Zn-Cu alloys fabricated by optimum processing parameters exhibit a tensile strength of 157.13 MPa,yield strength of 106.48 MPa and elongation of 14.7%.This work provides a comprehensive understanding of the processing optimization of Zn-Cu alloy,achieving LPBFed Zn-Cu alloy with high density and excellent mechanical properties. 展开更多
关键词 laser powder-bed fusion Zn alloys single track processing parameters mechanical properties
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Enhanced engineering and biocidal polypropylene filaments enabling melt reduction of AgNO_(3) through PVP agent:A scalable process for the defense industry with MEX additive manufacturing
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作者 Markos Petousis Nikolaos Michailidis +7 位作者 Vassilis Papadakis Apostolos Argyros Mariza Spiridaki Nikolaos Mountakis John Valsamos Nektarios K.Nasikas Amalia Moutsopoulou Nectarios Vidakis 《Defence Technology(防务技术)》 2025年第2期52-66,共15页
This study focused on the production of polypropylene(PP)/silver(Ag)composites via additive manufacturing.This study aimed to enhance the quality of medical-grade PP in material extrusion(MEX)three-dimensional printin... This study focused on the production of polypropylene(PP)/silver(Ag)composites via additive manufacturing.This study aimed to enhance the quality of medical-grade PP in material extrusion(MEX)three-dimensional printing(3DP)by improving its mechanical properties while simultaneously adding antibacterial properties.The latter can find extremely important and versatile properties that are applicable in defense and security domains.PP/Ag nanocomposites were prepared using a novel method based on a reaction occurring while mixing appropriate quantities of the starting polymers and additives,namely polyvinylpyrrolidone(PVP)as the matrix material and silver nitrate(AgNO_(3))as the filler.This process produced three-dimensional(3D)printed filaments,which were then used to create specimens for a series of standardized tests.It was found that the mechanical properties of the nanocomposites were enhanced in relation to pristine PP,especially for the PP matrix with various loadings of AgNO_(3)and PVP,such as 5.0 wt%and 2.5 wt%,respectively.The voids,inclusions,and actual-to-nominal dimensions also showed improved results.The 3DP specimens exhibited a more effective biocidal performance against Staphylococcus aureus than Escherichia coli,which developed an inhibition zone only in the case of PP with filler loading percentages of AgNO_(3)and PVP at 10.0 wt%and 5.0 wt%,respectively Compounds possessing such properties can be beneficial for various applications requiring increased mechanical properties and biocidal capabilities,such as in the Defence or medical industries. 展开更多
关键词 Polypropylene(PP) Polyvinyl pyrrolidone(PVP) Silver nitride(AgNO_(3)) In-situ reactive melt mixing process Material extrusion(MEX)3D printing Biocidal performance
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基于AHP-BPNN方法的高校学生人工智能素养指标体系构建 被引量:6
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作者 丁继红 郭丽媛 +1 位作者 张文轩 刘华中 《远程教育杂志》 北大核心 2025年第1期46-56,共11页
随着人工智能(artificial intelligence,AI)技术的快速发展及其在社会、经济和生活各领域的广泛应用,AI素养已成为提高生产力的必备能力。然而,针对高校学生群体的AI素养,目前尚缺乏统一且明确的指标体系。基于现有的AI素养框架,并通过... 随着人工智能(artificial intelligence,AI)技术的快速发展及其在社会、经济和生活各领域的广泛应用,AI素养已成为提高生产力的必备能力。然而,针对高校学生群体的AI素养,目前尚缺乏统一且明确的指标体系。基于现有的AI素养框架,并通过国内外专家的咨询反馈和指标修正,研究构建了一个包含知识与理解、技能与应用、评价与创造、伦理与道德等4个一级指标和17个二级指标的AI素养评价体系。随后,研究利用层次分析法确立了各级指标的权重,并通过构建反向传播神经网络对这些权重进行了验证。通过将专家知识引导与数据驱动相结合,研究最终构建了一个科学且具有较强操作性的AI素养指标体系,为我国高校学生AI素养评价提供了理论支持和工具借鉴。 展开更多
关键词 人工智能素养 层次分析法 反向传播神经网络 人工智能教育 学习评价
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进水分配比对分段进水PN/A工艺脱氮性能影响 被引量:2
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作者 李冬 王凯璐 +2 位作者 祝彦均 吕恒康 张杰 《中国环境科学》 EI CAS CSCD 北大核心 2024年第7期3672-3681,共10页
以预脱碳污水和市政污水作为目标污水,建立了好氧段分段进水的新模式,通过调整进水分配比来优化好氧段C/N,以期实现短程硝化-厌氧氨氧化(PN/A)工艺在实际工况下的稳定运行.采用4组以好氧/缺氧/好氧/缺氧(O/A/O/A)模式运行的序批式反应器... 以预脱碳污水和市政污水作为目标污水,建立了好氧段分段进水的新模式,通过调整进水分配比来优化好氧段C/N,以期实现短程硝化-厌氧氨氧化(PN/A)工艺在实际工况下的稳定运行.采用4组以好氧/缺氧/好氧/缺氧(O/A/O/A)模式运行的序批式反应器(SBR),R1、R2、R3及R4以进水分配比(预脱碳污水:市政污水)分别为1:0、2:1、1:1及1:2的分段进水模式运行.结果表明,R1未能实现PN/A工艺,总氮去除率(NRE)仅为60.2%.随着进水分配比不断下降,R2、R3、R4分别在第34,30及36d实现PN/A工艺,NRE分别达到71.8%、80.3%及74.1%.其中R3系统处理性能最好且最稳定,厌氧氨氧化贡献率达到83.9%.污泥沉降性与粒径最佳.此外,高通量结果显示氨氧化菌(Nitrosomonas)和厌氧氨氧化菌(Candidatus_Kuenenia)丰度分别为2.74%和12.17%,且与好氧异养菌(AHB)形成了良好的协同作用.因此,分段进水模式在进水分配比为1:1时有利于实现稳定的PN/A工艺,此时各功能微生物可得到较好富集与平衡. 展开更多
关键词 分段进水 pn/a工艺 进水分配比 竞争性抑制
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pnCCD的实时X射线成像数据采集系统
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作者 霍嘉 赵晓帆 +3 位作者 崔苇苇 王于仨 王昊 陈勇 《光学精密工程》 CSCD 北大核心 2024年第21期3166-3173,共8页
根据pnCCD的工作特点,采用多线程处理和多帧图像叠合技术,研制了基于pnCCD的实时X射线成像数据采集系统。为了满足高速数据实时采集与缓存的需求,硬件采用DDR3存储器接收缓存探测器机箱的科学数据。上位机软件采用LabVIEW的列队操作函... 根据pnCCD的工作特点,采用多线程处理和多帧图像叠合技术,研制了基于pnCCD的实时X射线成像数据采集系统。为了满足高速数据实时采集与缓存的需求,硬件采用DDR3存储器接收缓存探测器机箱的科学数据。上位机软件采用LabVIEW的列队操作函数实现了数据采集、存储、多帧叠合成像的多线程处理,并设计了多模式下的实时图像处理模块。测试结果表明,该数据采集系统满足pnCCD各工作模式下的数据采集,实时的图像处理快速呈现了聚焦相机成像的位置信息,加快完成在X射线标定装置中聚焦相机对轴对焦等实验过程。数据采集系统通信稳定可靠,具有很好的灵活性和可移植性。 展开更多
关键词 X射线成像 pn结电荷耦合器件(pnCCD) 数据采集 LABVIEW
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短周期PN序列水声直扩系统抗单频干扰能力的变化规律与试验验证 被引量:1
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作者 王晓玮 周其斗 +2 位作者 唐永壮 谢志勇 刘文玺 《海军工程大学学报》 CAS 北大核心 2024年第2期43-49,共7页
对无法定量分析短周期PN序列直扩系统抗单频干扰性能的问题,首先通过理论推导得到单频干扰经相关处理产生的干扰分量;然后,结合直扩系统对单频干扰的处理增益,针对水声系统扩频序列周期较短的现实情况,提出了周期性PN序列水声直扩系统... 对无法定量分析短周期PN序列直扩系统抗单频干扰性能的问题,首先通过理论推导得到单频干扰经相关处理产生的干扰分量;然后,结合直扩系统对单频干扰的处理增益,针对水声系统扩频序列周期较短的现实情况,提出了周期性PN序列水声直扩系统抗单频干扰性能定量分析的理论表达式;最后,通过仿真和试验验证了理论表达式的正确性。结果表明:单频干扰经相关处理后得到的干扰序列呈直流或正弦分布;单频干扰对系统误码率的影响与信干比、干扰频偏、相位偏差以及扩频码本身结构有关,误码率随干扰相位偏差变化呈周期分布;在干扰频偏值为整数倍码元带宽的所有工况中,频偏为一倍码元带宽的单频干扰对系统影响最大;简明的理论表达式,对快速预报现实短码水声系统抗单频干扰性能的变化规律具有重要意义。 展开更多
关键词 水声通信 短周期pn序列 单频干扰 标准高斯近似
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基于HCPN的复杂BPMN协作模型数据流建模与验证 被引量:4
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作者 黄凤兰 倪枫 +3 位作者 刘姜 陶蒙怡 周奕宁 李业勋 《计算机集成制造系统》 EI CSCD 北大核心 2024年第5期1754-1769,共16页
为了保证复杂BPMN协作模型的正确性,不仅要涵盖多实例和子进程等复杂元素,还要在检测控制流错误的同时检测数据流错误。但业务流程建模标注(BPMN 2.0)缺乏形式化语义的描述,这对模型正确性的验证造成了阻碍。因此,给出了一种具有弧权重... 为了保证复杂BPMN协作模型的正确性,不仅要涵盖多实例和子进程等复杂元素,还要在检测控制流错误的同时检测数据流错误。但业务流程建模标注(BPMN 2.0)缺乏形式化语义的描述,这对模型正确性的验证造成了阻碍。因此,给出了一种具有弧权重的层次化着色Petri网(HCPN)的定义,它既可以对数据流进行形式化表示,又可以对多实例和子进程结构进行建模。进一步提出了从BPMN协作模型到HCPN模型的形式化映射方法。然后基于HCPN模型的弧权重给出了缺失、丢失和冗余3种数据流错误的定义,并提出了对应的检测算法。最后,设计了一个自动化建模与验证的框架,通过一个案例研究说明了该方法的有效性。 展开更多
关键词 着色PETRI网 BPMN协作模型 数据流错误 模型验证 形式化
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PN-ANAMMOX两段法处理污泥消化液 被引量:2
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作者 李霞 李惠娟 +3 位作者 王理明 高敏 梅若晨 张典奥 《环境化学》 CAS CSCD 北大核心 2024年第11期3921-3934,共14页
通过将部分亚硝化(PN)与厌氧氨氧化(ANAMMOX)组合形成两段法,研究了该工艺在处理污泥消化液过程中氮素的转化规律、脱氮效果、影响因素及污泥消化液对两段法系统中微生物种群的影响.结果表明两段法可对实际的污泥消化液进行有效处理,在... 通过将部分亚硝化(PN)与厌氧氨氧化(ANAMMOX)组合形成两段法,研究了该工艺在处理污泥消化液过程中氮素的转化规律、脱氮效果、影响因素及污泥消化液对两段法系统中微生物种群的影响.结果表明两段法可对实际的污泥消化液进行有效处理,在进水氨氮浓度为1000 mg·L^(−1),部分亚硝化反应器和厌氧氨氧化反应器的HRT分别为1d时,两段法对总氮平均去除率为83.37%.不调节进水碱度,PN反应器出水NO_(2)^(-)-N/NH_(4)^(+)-N的比值大于1,满足了ANAMMOX反应对基质浓度的要求,为ANAMMOX反应器的后续运行创造了有利条件.ANAMMOX反应中NH_(4)^(+)-N、NO_(2)^(-)-N的消耗量与NO_(3)^(-)-N生成量之间的比例关系为1∶(1.14±0.10)∶(0.18±0.02),低于理论值.PN和ANAMMOX污泥样品中关键微生物分别为Proteobacteria和Planctomycetes(门水平),在处理消化液前其相对丰度分别为65.2%、38.85%,在处理消化液后其相对丰度分别为35.36%和19.05%.实际消化液中的有机物导致其它异养微生物在两个反应器的污泥中增殖,降低了氨氧化菌(AOB)和厌氧氨氧化菌(AnAOB)的相对丰度,但对其种属无明显影响,因此并不影响两段式PN/A工艺的脱氮效率.通过DO+FNA和DO+FA交替控制PN反应器运行,并通过控制ANAMMOX反应器进水NO_(2)^(-)−N/NH_(4)^(+)-N的比值可实现ANAMMOX的稳定运行,从而保证了两段法工艺对污泥水的高效脱氮处理. 展开更多
关键词 污泥消化液 部分亚硝化 厌氧氨氧化 微生物种群 高通量测序
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