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Numerical Simulation of the Atomization Process for Blast Furnace Slag Granulation
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作者 Li-Li Wang Hong-Xing Qin Nan Dong 《Fluid Dynamics & Materials Processing》 2025年第6期1489-1503,共15页
The so-called close-coupled gas atomization process involves melting a metal and using a high-pressure gas jet positioned close to the melt stream to rapidly break it into fine,spherical powder particles.This techniqu... The so-called close-coupled gas atomization process involves melting a metal and using a high-pressure gas jet positioned close to the melt stream to rapidly break it into fine,spherical powder particles.This technique,adapted for blast furnace slag granulation using a circular seam nozzle,typically aims to produce solid slag particles sized 30–140μm,thereby allowing the utilization of slag as a resource.This study explores the atomization dynamics of liquid blast furnace slag,focusing on the effects of atomization pressure.Primary atomization is simulated using a combination of the Volume of Fluid(VOF)method and the Shear Stress Transport k-ωturbulence model,while secondary atomization is analyzed through the Discrete Phase Model(DPM).The results reveal that primary atomization progresses in three stages:the slag column transforms into an umbrella-shaped liquid film,whose leading edge fragments into particles while forming a cavity-like structure,which is eventually torn into ligaments.This primary deformation is driven by the interplay of airflow velocity in the recirculation zone and the guide tube outlet pressure(Fp).Increasing the atomization pressure amplifies airflow velocity,recirculation zone size,expansion and shock waves,though the guide tube outlet pressure variations remain irregular.Notably,at 4.5 MPa,the primary deformation is most pronounced.Secondary atomization yields finer slag particles as a result of more vigorous primary atomization.For this pressure,the smallest average particle size and the highest yield of particles within the target range(30–140μm)are achieved. 展开更多
关键词 Blast furnace slag granulation close-coupled gas atomization atomization pressure atomization process
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Effects of pressure oscillations on impinging-jet atomization and spray combustion in liquid rocket engines
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作者 Zhili PENG Bo ZHONG +1 位作者 Xiaodong CHEN Longfei LI 《Chinese Journal of Aeronautics》 2025年第4期25-43,共19页
Combustion dynamics are a critical factor in determining the performance and reliabilityof a chemical propulsion engine.The underlying processes include liquid atomization,evaporation,mixing,and chemical reactions.Thi... Combustion dynamics are a critical factor in determining the performance and reliabilityof a chemical propulsion engine.The underlying processes include liquid atomization,evaporation,mixing,and chemical reactions.This paper presents a high-fidelity numerical study of liquidatomization and spray combustion under high-pressure conditions,emphasizing the effects of pres-sure oscillations on the flow evolution and combustion dynamics.The theoretical framework isbased on the three-dimensional conservation equations for multiphase flows and turbulent combus-tion.The numerical solution is achieved using a coupling method of volume-of-fluid and Lagran-gian particle tracking.The Zhuang-Kadota-Sutton(ZKS)high-pressure evaporation model andthe eddy breakup-Arrhenius combustion model are employed.Simulations are conducted for amodel combustion chamber with impinging-jet injectors using liquid oxygen and kerosene as pro-pellants.Both conditions with and without inlet and outlet pressure oscillations are considered.Thefindings reveal that pressure oscillations amplify flow fluctuations and can be characterized usingkey physical parameters such as droplet evaporation,chemical reaction,and chamber pressure.The spectral analysis uncovers the axial variations of the dominant and secondary frequenciesand their amplitudes in terms of the characteristic physical quantities.This research helps establisha methodology for exploring the coupling effect of liquid atomization and spray combustion.It alsoprovides practical insights into their responses to pressure oscillations during the occurrence ofcombustion instability.This information can be used to enhance the design and operation ofliquid-fueled propulsion engines. 展开更多
关键词 Liquid atomization Spray combustion Pressure oscillations High-pressure evaporation Combustion instability
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Mechanistic insights and practical applications of impinging-jet dynamics and atomization
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作者 Yongze An Bo Wang +2 位作者 Zhili Peng Xiaodong Chen Vigor Yang 《Acta Mechanica Sinica》 2025年第7期21-37,共17页
This review summarizes recent progress in the study of impinging-jet dynamics and atomization,with a focus on liquid sheet formation,instability mechanisms,and the influence of key parameters such as fluid properties,... This review summarizes recent progress in the study of impinging-jet dynamics and atomization,with a focus on liquid sheet formation,instability mechanisms,and the influence of key parameters such as fluid properties,Weber number,and Reynolds number.Special attention is given to atomization behaviors under high pressure and external perturbations.Representative experimental and numerical approaches are introduced,and critical findings under complex conditions are highlighted.In addition,practical applications of impinging-jet technology in aerospace propulsion,biomedical devices,and energy science are discussed.This review aims to serve as a concise reference for researchers interested in multiphase flow dynamics and engineering applications of impinging jets. 展开更多
关键词 Impinging jets Liquid sheet breakup atomization Interfacial instability Spray dynamics Multiphase flow
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A simple atomization approach enables monolayer dispersion of nano graphenes in cementitious composites with excellent strength gains
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作者 Nanxi Dang Rijiao Yang +4 位作者 Chengji Xu Yu Peng Qiang Zeng Weijian Zhao Zhidong Zhang 《Nano Materials Science》 EI CAS CSCD 2024年第2期211-222,共12页
Carbon nano additives(CNAs)are critical to achieving the unique properties of functionalized composites,however,controlling the dispersion of CNAs in material matrix is always a challenging task.In this study,a simple... Carbon nano additives(CNAs)are critical to achieving the unique properties of functionalized composites,however,controlling the dispersion of CNAs in material matrix is always a challenging task.In this study,a simple atomization approach was successfully developed to promote the dispersion efficiency of graphene nanoplatelets(GNPs)in cement composites.This atomization approach can be integrated with the direct,indirect and combined ultrasonic stirrings in a homemade automatic stirring-atomization device.Mechanical and microstructure tests were performed on hardened cement pastes blended with GNPs in different stirring and mixing approaches.Results show that the direct ultrasonic stirrings enabled more homogeneous dispersions of GNP particles with a smaller size for a longer duration.The atomized droplets with the mean size of~100μm largely mitigated GNPs’agglomerations.Monolayer GNPs were observed in the cement matrix with the strength gain by up to 54%,and the total porosity decrease by 21%in 0.3 wt%GNPs dosage.The greatly enhanced dispersion efficiency of GNPs in cement also raised the cement hydration.This work provides an effective and manpower saving technique toward dispersing CNAs in engineering materials with great industrialization prospects. 展开更多
关键词 NANOMATERIALS DISPERSION atomization STRENGTH Microstructure
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Research Progress of Atomizers and Drugs Used in Atomization Therapy
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作者 Bozhi LIU Haobo YANG +2 位作者 Yifei CHEN Xiaojing SUN Qian JIANG 《Medicinal Plant》 2024年第4期77-79,82,共4页
At present,the commonly used treatment methods for chronic respiratory diseases are drug,oxygen,interventional and atomization therapy.Atomization therapy is the most widely used because of its characteristics of fast... At present,the commonly used treatment methods for chronic respiratory diseases are drug,oxygen,interventional and atomization therapy.Atomization therapy is the most widely used because of its characteristics of fast effect,high local drug concentration,less drug dosage,convenient application and few systemic adverse reactions.In this paper,the mechanism,characteristics,commonly used drugs and clinical application of atomization therapy are discussed. 展开更多
关键词 Ultrasonic atomizer Atomized drugs atomization therapy
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A novel method for atomization energy prediction based on natural-parameter network
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作者 Chaoqin Chu Qinkun Xiao +5 位作者 Chaozheng He Chen Chen Lu Li Junyan Zhao Jinzhou Zheng Yinhuan Zhang 《Chinese Chemical Letters》 SCIE CAS CSCD 2024年第1期505-509,共5页
Atomization energy(AE)is an important indicator for measuring material stability and reactivity,which refers to the energy change when a polyatomic molecule decomposes into its constituent atoms.Predicting AE based on... Atomization energy(AE)is an important indicator for measuring material stability and reactivity,which refers to the energy change when a polyatomic molecule decomposes into its constituent atoms.Predicting AE based on the structural information of molecules has been a focus of researchers,but existing methods have limitations such as being time-consuming or requiring complex preprocessing and large amounts of training data.Deep learning(DL),a new branch of machine learning(ML),has shown promise in learning internal rules and hierarchical representations of sample data,making it a potential solution for AE prediction.To address this problem,we propose a natural-parameter network(NPN)approach for AE prediction.This method establishes a clearer statistical interpretation of the relationship between the network’s output and the given data.We use the Coulomb matrix(CM)method to represent each compound as a structural information matrix.Furthermore,we also designed an end-to-end predictive model.Experimental results demonstrate that our method achieves excellent performance on the QM7 and BC2P datasets,and the mean absolute error(MAE)obtained on the QM7 test set ranges from 0.2 kcal/mol to 3 kcal/mol.The optimal result of our method is approximately an order of magnitude higher than the accuracy of 3 kcal/mol in published works.Additionally,our approach significantly accelerates the prediction time.Overall,this study presents a promising approach to accelerate the process of predicting structures using DL,and provides a valuable contribution to the field of chemical energy prediction. 展开更多
关键词 Structure prediction atomization energy Deep learning Coulomb matrix NPN END-TO-END
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Coordination of distinctive pesticide adjuvants and atomization nozzles on droplet spectrum evolution for spatial drift reduction
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作者 Shidong Xue Jingkun Han +3 位作者 Xi Xi Zhong Lan Rongfu Wen Xuehu Ma 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第2期250-262,共13页
Pesticide adjuvants,as crop protection products,have been widely used to reduce drift loss and improve utilization efficiency by regulating droplet spectrum.However,the coordinated regulation mechanisms of adjuvants a... Pesticide adjuvants,as crop protection products,have been widely used to reduce drift loss and improve utilization efficiency by regulating droplet spectrum.However,the coordinated regulation mechanisms of adjuvants and nozzles on droplet spectrum remain unclear.Here,we established the relationship between droplet spectrum evolution and liquid atomization by investigating the typical characteristics of droplet diameter distribution near the nozzle.Based on this,the regulation mechanisms of distinctive pesticide adjuvants on droplet spectrum were clarified,and the corresponding drift reduction performances were quantitively evaluated by wind tunnel experiments.It shows that the droplet diameter firstly shifts to the smaller due to the liquid sheet breakup and then prefers to increase caused by droplet interactions.Reducing the surface tension of sprayed liquid facilitates the uniform liquid breakup and increasing the viscosity inhibits the liquid deformation,which prolong the atomization process and effectively improve the droplet spectrum.As a result,the drift losses of flat-fan and hollow cone nozzles are reduced by about 50%after adding organosilicon and vegetable oil adjuvants.By contrast,the air induction nozzle shows a superior anti-drift ability,regardless of distinctive adjuvants.Our findings provide insights into rational adjuvant design and nozzle selection in the field application. 展开更多
关键词 Pesticide drift Spray droplets Particle size distribution Spray atomization Transport processes ADJUVANTS
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Investigations on High-Speed Flash Boiling Atomization of Fuel Based on Numerical Simulations
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作者 Wei Zhong Zhenfang Xin +1 位作者 Lihua Wang Haiping Liu 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第5期1427-1453,共27页
Flash boiling atomization(FBA)is a promising approach for enhancing spray atomization,which can generate a fine and more evenly distributed spray by increasing the fuel injection temperature or reducing the ambient pr... Flash boiling atomization(FBA)is a promising approach for enhancing spray atomization,which can generate a fine and more evenly distributed spray by increasing the fuel injection temperature or reducing the ambient pressure.However,when the outlet speed of the nozzle exceeds 400 m/s,investigating high-speed flash boiling atomization(HFBA)becomes quite challenging.This difficulty arises fromthe involvement ofmany complex physical processes and the requirement for a very fine mesh in numerical simulations.In this study,an HFBA model for gasoline direct injection(GDI)is established.This model incorporates primary and secondary atomization,as well as vaporization and boilingmodels,to describe the development process of the flash boiling spray.Compared to lowspeed FBA,these physical processes significantly impact HFBA.In this model,the Eulerian description is utilized for modeling the gas,and the Lagrangian description is applied to model the droplets,which effectively captures the movement of the droplets and avoids excessive mesh in the Eulerian coordinates.Under various conditions,numerical solutions of the Sauter mean diameter(SMD)for GDI show good agreement with experimental data,validating the proposed model’s performance.Simulations based on this HFBA model investigate the influences of fuel injection temperature and ambient pressure on the atomization process.Numerical analyses of the velocity field,temperature field,vapor mass fraction distribution,particle size distribution,and spray penetration length under different superheat degrees reveal that high injection temperature or low ambient pressure significantly affects the formation of small and dispersed droplet distribution.This effect is conducive to the refinement of spray particles and enhances atomization. 展开更多
关键词 High-speed flash boiling atomization numerical simulations Eulerian description Lagrangian description gasoline direct injection
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面向6G无线通信的里德堡原子天线:技术架构与应用前瞻 被引量:1
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作者 王莹 郭余庆 +1 位作者 郭旭沨 张平 《通信学报》 北大核心 2025年第7期191-205,共15页
里德堡原子天线凭借碱金属原子(如铷和铯)的高能级激发态(即里德堡态)对电磁波的高灵敏度响应特性,能够实现对特定频率窄带电磁波振幅、频率和相位的精确测量。与传统天线相比,里德堡原子天线展现出了诸多适用于下一代6G无线通信系统的... 里德堡原子天线凭借碱金属原子(如铷和铯)的高能级激发态(即里德堡态)对电磁波的高灵敏度响应特性,能够实现对特定频率窄带电磁波振幅、频率和相位的精确测量。与传统天线相比,里德堡原子天线展现出了诸多适用于下一代6G无线通信系统的良好特性,包括超宽带调谐特性、窄带响应特性、无热噪声特性和极高的灵敏度。首先,通过阐释里德堡原子的量子模型,揭示了里德堡原子天线的工作机理。随后,对其噪声来源进行系统分析,凸显出相较传统导体天线的显著低噪声优势。在此基础上,总结了该天线在无线通信与感知领域的应用与研究进展,并基于其低噪声和高灵敏度特性提出了未来的应用前景。 展开更多
关键词 里德堡原子 原子天线 量子传感 噪声功率
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A cutting-edge atomization-based methodology for enhancing formulation ability to resist photoaging
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作者 Juntong Li Shuyu Wang +4 位作者 Ruifang Han Meifang Wu Jian Zhou Peibiao Zhao Bin Cui 《Journal of Dermatologic Science and Cosmetic Technology》 2024年第4期46-53,共8页
Background:Skin photoaging mainly occurs in exposed skin irradiated by ultraviolet rays from the sunlight.When exposed to ultraviolet rays,the skin will undergo certain changes to avoid damage.The inflammatory factors... Background:Skin photoaging mainly occurs in exposed skin irradiated by ultraviolet rays from the sunlight.When exposed to ultraviolet rays,the skin will undergo certain changes to avoid damage.The inflammatory factors produced by light stimulation will induce melanocytes to produce more melanin,leading to the skin shows a rough,dark,dry,loose,and leathery appearance.In particular,when the skin is exposed to external damage and then received the damage of sunlight,such as after an aesthetic medicine treatment,it is more likely to produce post-inflammatory hyperpigmentation(PIH).However,there is a lack of a non-invasive and efficient solution.Objective:The purpose of this study is to verify a new skincare method to resist photoaging.The essence itself has a very good effect in resisting photodamage,when it through atomized to skin,it showcases a non-invasive but better-result approach to skin care.Materials and methods:This study assessed anti-photoaging effects through in vitro(antioxidant,UVB protection,ROS tests)and human trials.In vitro results indicate the essence's efficacy.A randomized trial with 60 women(20–45 years,sensitive skin)compared atomized essence vs.smear control.After 28 days,atomized essence improved skin hydration,gloss,reduced redness,TiVi,TEWL,and UV protection.A 7-day test with Moyal Luminous Serum and Atomizer showed this skincare combo effectively prevents photodamage.Results:Through in vitro and human experiments,we have verified that the self-developed essence itself has a very good effect of anti-photoaging.Through further comparison of human efficacy tests,we found that with the support of an atomizer,the anti-photoaging effect of the essence has been improved.Conclusion:Essence through atomization to resists photoaging,improves skin moisture,gloss,UV protection and reduces redness.Its non-invasive delivery ensures efficacy and user-friendliness. 展开更多
关键词 SUNLIGHT Skin photoaging Post-inflammatory hyperpigmentation atomization NON-INVASIVE
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原子层沉积法制备HfO_(2)/Al_(2)O_(3)X射线多层膜 被引量:2
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作者 赵慧斌 李艳丽 +2 位作者 张贺 牛耕 韩立 《硅酸盐学报》 北大核心 2025年第4期958-964,共7页
X射线多层膜可实现特定波长X射线的高效反射,是获得单色X射线的一种重要元件。由于X射线的波长短,多层膜的周期厚度通常为纳米量级,高精度膜厚控制的原子层沉积(ALD)法是制备X射线多层膜的一种有效方法。对于常用的0.154 nm X射线,HfO_(... X射线多层膜可实现特定波长X射线的高效反射,是获得单色X射线的一种重要元件。由于X射线的波长短,多层膜的周期厚度通常为纳米量级,高精度膜厚控制的原子层沉积(ALD)法是制备X射线多层膜的一种有效方法。对于常用的0.154 nm X射线,HfO_(2)/Al_(2)O_(3)是一种有效的多层膜材料组合,为进一步研究ALD法制备的HfO_(2)/Al_(2)O_(3)X射线多层膜的特性,探索多层膜的应用,利用ALD法制备了周期厚度3.8 nm、周期数60的Hf O_(2)/Al_(2)O_(3)多层膜,表征结果显示:多层膜为非晶薄膜,表面粗糙度为0.77 nm,膜层间的界面清晰,周期厚度的最大偏差为0.11 nm,多层膜的X射线(0.154 nm)最高反射率约为45%。将HfO_(2)/Al_(2)O_(3)多层膜应用于X射线衍射仪中,测试同一硅粉样品,测试结果显示:安装多层膜后,衍射谱的背底强度降低,且未见杂峰,展现出HfO_(2)/Al_(2)O_(3)多层膜的应用潜力。 展开更多
关键词 X射线 氧化铪/氧化铝多层膜 原子层沉积 衍射仪
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活性纳米颗粒与岩石表面间微观力学作用实验解析与润湿调控预测 被引量:1
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作者 袁彬 韩明亮 +1 位作者 张伟 李东明 《中国石油大学学报(自然科学版)》 北大核心 2025年第1期120-127,共8页
微观作用力决定了纳米颗粒在岩石壁面的吸附行为,进而影响纳米颗粒调控壁面润湿性的能力。基于原子力显微镜测量活性SiO_(2)颗粒与石英基底间作用力,建立力学作用理论模型并分析其主控因素;进行纳米颗粒在壁面吸附的分子动力学模拟,验... 微观作用力决定了纳米颗粒在岩石壁面的吸附行为,进而影响纳米颗粒调控壁面润湿性的能力。基于原子力显微镜测量活性SiO_(2)颗粒与石英基底间作用力,建立力学作用理论模型并分析其主控因素;进行纳米颗粒在壁面吸附的分子动力学模拟,验证力学模型的合理性;基于力学机制建立预测纳米颗粒调控壁面润湿性的数学模型。结果表明:溶液离子浓度越大或离子价态越高,活性SiO_(2)颗粒与石英基底间作用力越倾向于表现为引力,所建立的力学模型可高效拟合二者间力学数据;二者间力学作用可由离子浓度、纳米颗粒表面修饰分子的长度等因素调控,但离子浓度为主控因素;在双对数曲线中纳米颗粒在壁面的黏附功和壁面油相接触角的变化值呈线性关系。 展开更多
关键词 提高采收率 活性纳米颗粒 原子力显微镜 润湿调控 纳米力学
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原子层热电堆热流传感器的发展及其应用 被引量:1
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作者 杨凯 陈曦 +3 位作者 朱涛 陶伯万 赵睿鹏 王辉 《实验流体力学》 北大核心 2025年第2期1-14,共14页
高频脉动热流在高超声速边界层转捩、激波/边界层干扰等气动基础问题的实验研究中非常重要。当前,高频脉动热流测试主要依赖于原子层热电堆(Atomic Layer Thermopile,ALTP)热流传感器。采用金属有机化学气相沉积技术路线,在优化沉积环... 高频脉动热流在高超声速边界层转捩、激波/边界层干扰等气动基础问题的实验研究中非常重要。当前,高频脉动热流测试主要依赖于原子层热电堆(Atomic Layer Thermopile,ALTP)热流传感器。采用金属有机化学气相沉积技术路线,在优化沉积环境条件参数的基础上发展了性能更优的ALTP热流传感器。面向传感器小型化、耐高温、柔性等发展需求,通过导电膜连接将多条YBa_(2)Cu_(3)O_(7)-δ(YBCO)薄膜首尾串联,在保持传感器尺寸不变的同时提高灵敏度系数,为传感器小型化奠定了基础;通过替换常规ALTP热流传感器敏感元的热电材料体系,研制了基于La1-xCaxMnO_(3)(LCMO)的耐高温(超过500℃)ALTP热流传感器样件。针对LCMO的能量输运特点,采用半导体材料性能调控方法,以交替串联的方式延长敏感薄膜的有效长度,进而能在有限的传感器感应面上布置更多的敏感薄膜;以表面经特殊处理的金属薄带为基底替换斜切SrTiO_(3)晶片,发展了柔性ALTP热流传感器,便于开展高频脉动热流的密集点测试以及在复杂曲面等位置布放高频脉动热流测点。传感器应用方面,除在激波风洞等实验环境下开展高频脉动热流测试的应用外,针对薄膜热电阻和同轴热电偶标定环节多、测热结果不确定度偏高等问题,讨论了利用ALTP热流传感器在线标定的可行性;针对高超声速低密度风洞中的薄壁量热计、同轴热电偶和红外热图等测热方式易受噪声干扰、不确定度高以及有效时间短等问题,通过风洞实验验证了ALTP热流传感器在高超声速低密度风洞中长时间中低热流测试的可行性,弥补了现有测热手段的不足。 展开更多
关键词 原子层热电堆 热流 标定 柔性 耐高温 高频脉动
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固液界面水化膜结构研究进展 被引量:1
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作者 张娜 寇珏 孙春宝 《工程科学学报》 北大核心 2025年第3期401-410,共10页
固液界面广泛存在于物质世界中,界面性质的变化在矿物浮选、石油开采以及土壤改良等领域具有重要作用,水化膜作为固液界面上的微纳米结构,对固液界面性质起到决定性的作用,水化膜的结构与厚度受固体表面性质与溶液性质的影响.本文以云... 固液界面广泛存在于物质世界中,界面性质的变化在矿物浮选、石油开采以及土壤改良等领域具有重要作用,水化膜作为固液界面上的微纳米结构,对固液界面性质起到决定性的作用,水化膜的结构与厚度受固体表面性质与溶液性质的影响.本文以云母和方解石两种常见矿物为例,总结了利用X射线反射率测量和原子力显微镜观察两种方法探索矿物-水界面水化膜结构的研究进展,探讨了不同矿物表面水化膜的结构特点,讨论了溶液中金属阳离子及矿物表面解离离子对水化膜结构的影响,对比了两种方法所测水化膜结构的异同点.旨在深化对固液界面水合结构的理解,推动水化膜动力学行为的深入研究. 展开更多
关键词 水化膜 X射线反射率 原子力显微镜 云母 方解石
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RuO_(x)分散性导致的活性氧异化与氯苯氧化相关性 被引量:1
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作者 陈曦 贾子良 +5 位作者 王梦雪 王鹏 季鑫佟 乔昕茹 郭冬瑞 梁美生 《中国环境科学》 北大核心 2025年第4期1820-1832,共13页
在相同的催化剂载体TiCeO_(x)和贵金属含量下,利用Ru^(3+)浸渍还原(自下而上)和Ru胶体溶液热扩散(自上而下)两种方法制备具有不同分散性的贵金属负载型催化剂.其中Ru^(3+)浸渍还原法制备的催化剂RuTiCeO_(x)-N中,Ru物种以RuO_(x)纳米团... 在相同的催化剂载体TiCeO_(x)和贵金属含量下,利用Ru^(3+)浸渍还原(自下而上)和Ru胶体溶液热扩散(自上而下)两种方法制备具有不同分散性的贵金属负载型催化剂.其中Ru^(3+)浸渍还原法制备的催化剂RuTiCeO_(x)-N中,Ru物种以RuO_(x)纳米团簇的形式存在;Ru胶体溶液热扩散法制备的催化剂RuTiCeO_(x)-A中,Ru物种以单原子分散的形式存在.Ru物种不同的分散状态导致其参与氯苯(CB)氧化反应的活性氧物种和酸性位点的差异性,其中RuTiCeO_(x)-N中的主要活性氧物种为化学吸附氧,RuTiCeO_(x)-A中的主要活性氧物种为表面晶格氧.CB的化学吸附诱使活性氧物种转变为羟基(-OH)官能团参与催化反应.在活性氧物种和强弱多种酸性位的共同作用下,RuTiCeO_(x)-A催化剂表现出了优异的活性和稳定性,CB在300℃可以完全转化,且可以维持24h而不失活. 展开更多
关键词 催化剂载体 贵金属 团簇 单原子分散 氧物种 羟基
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超级微波消解-电感耦合等离子体原子发射光谱(ICP-AES)法测定不同类型土壤中的全硼 被引量:2
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作者 李霞 罗丽卉 +3 位作者 夏涵 王棚 杨定清 游蕊 《中国无机分析化学》 北大核心 2025年第8期1194-1200,共7页
为提高土壤全硼的检测效率和数据可靠性,利用超级微波消解仪对土壤样品进行消解,通过探究样品称样量、消解酸体系及消解温度等因素对全硼测定的影响,建立了超级微波消解-电感耦合等离子体原子发射光谱(ICP-AES)法测定不同类型土壤中全... 为提高土壤全硼的检测效率和数据可靠性,利用超级微波消解仪对土壤样品进行消解,通过探究样品称样量、消解酸体系及消解温度等因素对全硼测定的影响,建立了超级微波消解-电感耦合等离子体原子发射光谱(ICP-AES)法测定不同类型土壤中全硼的方法,并与传统碳酸钠熔融法进行了比较。结果表明,新建立方法的最优实验条件是在0.1 g土壤样品中加入硝酸-氢氟酸-高氯酸溶液(3 mL HNO_(3)+1.5 mL HF+1 mL HClO_(4)),放入超级微波中260℃温度下消解,使用超纯水定容至50 mL,然后采用电感耦合等离子体原子发射光谱(ICP-AES)法测定。新方法测定的全硼含量在0~1 mg/L线性关系良好,线性相关系数为0.999 9,方法检出限(LOD)为1.4 mg/kg,定量限(LOQ)为5.5 mg/kg。通过对土壤加标样品及标准物质的测定,加标回收率为97.1%~103%,相对标准偏差(RSD)为1.5%~3.0%,方法拥有良好的精密度和准确度,并且高效、准确、安全,可为不同类型土壤全硼含量的检测提供可靠的分析方法支撑。 展开更多
关键词 超级微波消解 电感耦合等离子发射光谱法 全硼 不同类型土壤
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基于铯基准钟与光抽运守时型小铯钟的时间尺度算法
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作者 宋会杰 董绍武 +6 位作者 王翔 章宇 郭栋 武文俊 吴丹 王心亮 刘丹丹 《物理学报》 北大核心 2025年第19期41-52,共12页
实现国家标准时间的自主可控在当前的国际形势下具有重要现实意义.本文通过研究基于自研铯基准钟和国产光抽运守时小铯钟,产生一个独立的、不依赖于外部参考的时间尺度.具体做法是将铯基准钟作为频率参考,用于预报光抽运守时小铯钟的频... 实现国家标准时间的自主可控在当前的国际形势下具有重要现实意义.本文通过研究基于自研铯基准钟和国产光抽运守时小铯钟,产生一个独立的、不依赖于外部参考的时间尺度.具体做法是将铯基准钟作为频率参考,用于预报光抽运守时小铯钟的频率漂移.通过分析光抽运守时小铯钟的噪声特性,建立了原子钟的状态方程,基于Kalman滤波算法估计光抽运守时小铯钟的状态.时间尺度的计算是基于原子钟的频率状态估计和频率漂移状态估计作为预报值,通过权重算法实现.研究了基于预测误差的权重算法和噪声特性的权重算法,结果表明利用Kalman滤波状态估计的情况下,基于预测误差的权重算法显著提升了独立时间尺度的准确度.选用铯基准钟作为频率参考,计算得到的独立时间尺度的准确度和长期稳定度明显优于时间尺度本身作为频率参考的情况.以国际标准时间UTCr为参考得出独立时间尺度的准确度保持在15 ns以内.取样间隔为1 d的频率稳定度为1.57×10^(-14),取样间隔为15 d的频率稳定度为4.29×10^(-15),取样间隔为30 d的频率稳定度为2.87×10^(-15).可满足当前国家用时需求. 展开更多
关键词 原子钟状态模型 原子钟噪声 时间尺度 KALMAN滤波
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旋流结构参数对压力旋流喷嘴雾化特性影响的数值模拟 被引量:1
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作者 付文锋 蔡泽萍 +1 位作者 王蓝婧 董帅 《华北电力大学学报(自然科学版)》 北大核心 2025年第1期126-134,共9页
应用Realizable k-ε湍流模型和VOF(Volume of Fraction)两相流模型对某压力旋流喷嘴进行数值研究,分析了旋流室锥角、旋流孔角度及喷嘴入口压力变化对雾化锥角、雾化粒径及分布、液滴速度分布等参数的影响。结果表明:雾化锥角受旋流室... 应用Realizable k-ε湍流模型和VOF(Volume of Fraction)两相流模型对某压力旋流喷嘴进行数值研究,分析了旋流室锥角、旋流孔角度及喷嘴入口压力变化对雾化锥角、雾化粒径及分布、液滴速度分布等参数的影响。结果表明:雾化锥角受旋流室锥角的影响幅度随压力增大而减小,雾化粒径及分布受旋流室锥角影响不明显,当旋流室锥角为90°时雾化范围广且雾化稳定性好;雾化锥角随旋流孔角度增大先增后减,当角度为45°时雾化锥角最大,平均粒径及其分布更佳;当喷嘴入口压力逐渐增大时,雾化锥角与雾化粒径均逐渐减小,液滴速度区间逐渐缩小,当入口压力达到0.4 MPa时,Sauter粒径及液滴粒径分布趋于稳定,液滴速度分布最为集中。 展开更多
关键词 压力旋流喷嘴 数值模拟 雾化特性 旋流室锥角 旋流孔角度
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空间原子氧防护涂层技术研究现状及挑战
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作者 王虎 何延春 +10 位作者 李中华 周超 李坤 李学磊 左华平 王晓毅 王兰喜 杨淼 李毅 周晖 张斌 《中国表面工程》 北大核心 2025年第1期40-56,共17页
原子氧防护涂层是保障低轨航天器长寿命高可靠的有效途径。简要阐述原子氧防护涂层的研究进展,对影响原子氧防护涂层性能的因素进行研究。结果表明,涂层的表面粗糙度会增加原子氧与材料表面的碰撞概率,涂层中的缺陷会提供原子氧的侵蚀通... 原子氧防护涂层是保障低轨航天器长寿命高可靠的有效途径。简要阐述原子氧防护涂层的研究进展,对影响原子氧防护涂层性能的因素进行研究。结果表明,涂层的表面粗糙度会增加原子氧与材料表面的碰撞概率,涂层中的缺陷会提供原子氧的侵蚀通道,涂层的成分与结构会影响原子氧反应的概率。调查空间原子氧防护涂层的种类,分析不同类型涂层的特点。无机涂层防护性能优异,但其柔韧性较差;有机硅涂层柔韧性较好,但在大通量原子氧作用下易出现缺陷;复合结构涂层可以满足多种功能复合的需求,但对工艺要求也较高。对涂层制备方法进行整理归纳,对比分析磁控溅射、等离子体增强化学气相沉积、离子束共沉积、原子层沉积、溶胶-凝胶、前驱体光解/水热固化六种不同制备技术的优缺点以及应用对象。分析介绍原子氧防护涂层的进一步发展趋势。研究结果为我国低轨航天器材料的原子氧防护提供必要的研究依据和参考,为原子氧防护涂层技术的发展提供研究思路。 展开更多
关键词 原子氧 防护 涂层 制备
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基于灰色关联分析法的双流体喷嘴喷雾特性研究
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作者 李刚 姜伯洋 +2 位作者 周刚 郭立稳 吴将有 《金属矿山》 北大核心 2025年第9期192-198,共7页
矿产资源高强度开发导致矿山粉尘问题愈发严重,严重威胁井下安全生产和工人职业健康。喷雾降尘技术可有效控制粉尘,喷雾特性的优劣与最终降尘效果相关性强,提升雾化效果可有效改善工作环境。双流体雾化喷嘴较单流体压力喷嘴优点明显,但... 矿产资源高强度开发导致矿山粉尘问题愈发严重,严重威胁井下安全生产和工人职业健康。喷雾降尘技术可有效控制粉尘,喷雾特性的优劣与最终降尘效果相关性强,提升雾化效果可有效改善工作环境。双流体雾化喷嘴较单流体压力喷嘴优点明显,但喷嘴内、外流场与液态介质之间相互作用复杂,现场应用中间环节参数研究不够深入,导致喷雾特性控制针对性不强,为高效降尘带来困难。基于此,以双流体雾化喷嘴中的空气雾化喷嘴为研究对象,研究了供水压力、供气压力2个关键参数对射程、水流量、气流量和D50、D905个喷雾特性参数的作用形式和影响规律,利用灰色关联分析法分析了不同参数对喷雾特性影响的重要度,确定了不同喷雾特性参数的敏感指标,并对喷雾过程进行了优化控制。研究结果表明:供水压力与射程、水流量和雾滴粒径呈正相关关系,供气压力与气流量呈正相关关系;射程和水流量、气流量、雾滴粒径分别对供水压力变化、供气压力变化、液气压力比变化敏感。研究结果可实现对喷雾特性的针对性调控,为加快建设矿山湿式控除尘体系提供理论依据。 展开更多
关键词 喷雾降尘 雾化效果 空气雾化喷嘴 灰色关联分析法 敏感指标
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