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Interplay between geometric and electronic structures of Pt entities over TiO_(2) for CO oxidation

Science China Chemistry 2024年第2期67卷 705-714页

作者： Xixiong Zhang Wen Shi shaobo han Yong Li Wenjie Shen School of Chemistry Dalian University of TechnologyDalian116024China State Key Laboratory of Catalysis Dalian Institution of Chemical PhysicsChinese Academy of SciencesDalian116023China

Monodispersed Pt colloids with a mean size of 2 nm were deposited uniformly on the {110} facets of a rod-shaped rutile TiO_(2),forming a well-defined Pt/TiO_(2) system.Oxidative treatment of this precursor at elevated temperatures re-dispersed the Pt particles into clusters and single-atoms.Air-calcination at 673 K partially oxidized the Pt particle surface,while calcination at 773 K yielded Pt Oxclusters of 1.6 nm in 7–8 atomic layers.Further calcination at 873 K formed a mixture of raft-like PtO_(x) clusters(1.6 nm,1–2 atomic layers) and cationic single-atoms.When tested for CO oxidation at 373 K,the Pt particles showed a higher activity than the Pt Oxclusters,whereas the cationic single-atoms were much less active.Subsequent H_(2)-reduction at 473 K converted the partially oxidized Pt particles into the metallic species,but they were encapsulated by TiO_(2)–xoverlayers because of the strong metal–support interactions,which decreased the activity dramatically.H_(2)-reduction of the PtO_(x) clusters at473 K enhanced the fraction of metallic Pt species without changing the size and geometry,and promoted the activity substantially.H_(2)-treatment of Pt single-atoms at 473 K increased the activity only moderately because most Pt species still kept at cationic species.These results straightforwardly differentiated the catalytic behavior of Pt particles,clusters and single-atoms at the same metal loading and over the same TiO_(2) support,and further demonstrated that the electronic structures of Pt entities played a decisive role in the catalytic oxidation,in addition to the specified sizes.

关键词： Pt/TiO_(2)catalyst size effect Pt clusters active sites electronic structures CO oxidation

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Single-element amorphous palladium nanoparticles formed via phase separation

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Nano Research 2022年第6期15卷 5575-5580页

作者： Dong Sheng He Yi Huang Benjamin D.Myers Dieter Isheim Xinyu Fan Guang-Jie Xia Yunsheng Deng Lin Xie shaobo han Yang Qiu Yang-Gang Wang Junhua Luan Zengbao Jiao Li Huang Vinayak P.Dravid Jiaqing He Pico Center and Department of Physics Southern University of Science and TechnologyShenzhen 518055China Department of Materials Science and Engineering Northwestern UniversityEvanstonIL 60208USA Department of Chemistry and Guangdong Provincial Key Laboratory of Catalytic Chemistry Southern University of Science and TechnologyShenzhen 518055China Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Department of Materials Science and Engineering City University of Hong KongHong KongChina Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHong KongChina

Physically vitrifying amorphous single-element metal requires ultrahigh cooling rates,which are still unachievable for most of the closest-packed metals.Here,we report a facile chemical synthetic strategy for single-element amorphous palladium nanoparticles with a purity of 99.35 at.%±0.23 at.%from palladium–silicon liquid droplets.In-situ transmission electron microscopy directly detected the solidification of palladium and the separation of silicon.Further hydrogen absorption experiment showed that the amorphous palladium expanded little upon hydrogen uptake,exhibiting a great potential application for hydrogen separation.Our results provide insight into the formation of amorphous metal at nanoscale.

关键词： Pd single-element metallic glass nanoparticle phase separation undercooling

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Coal-Biomass Preheating Combustion Characteristics in Cement Precalciner.Part 1:Preheating of Coal/Biomass

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Journal of Thermal Science 2023年第5期32卷 1868-1877页

作者： LI Pengpeng REN Qiangqiang han shaobo ZhanG Chi LYU Qinggang School of Energy Power and Mechanical Engineering North China Electric Power UniversityBeijing 102206China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

The co-combustion of biomass and coal can positively impact the environment and reduce the cost of power generation.However,biomass fuels have many limitations.Circulating fluidized bed(CFB)preheating combustion is suitable for co-combusting coal and biomass because of better fuel adaptability.In the cement industry,fuel combustion and raw meal decomposition in precalciners affect cement quality and cause pollutant emissions.The preheating combustion method used in precalciners can improve combustion performance and reduce NO_(x)emissions.This study investigated the preheating characteristics of a coal-biomass mixed fuel in a cement precalciner.The effects of load,biomass type,and biomass proportion on the preheated fuel and the conditions of the CFB were investigated.The results indicated that a lower load reduces the combustible components in gaseous and solid preheated fuels.However,due to the gas volume remains constant under different loads,a lower load also increases temperature and intensifies the reaction.The carbon chain and microscopic structural activities of preheated fuels are considerably enhanced,facilitating their combustion in precalciners and reducing nitrogen oxides in rotary kilns.Furthermore,adding biomass can improve the reactivity of a fuel subjected to preheating.Thus,biomass fuels(e.g.,rice husks)exhibit high combustion efficiency,and thus high energy utilization.The present study achieved better pore structure and molecular activity using preheated fuel from a CFB preheater.In addition,the improvement of pore structure and molecular activity increases with the proportion of the biomass.

关键词： cement precalciner biomass circulating fluidized bed preheating combustion

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3D interlocked all-textile structured triboelectric pressure sensor for accurately measuring epidermal pulse waves in amphibious environments

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Nano Research 2024年第3期17卷 1923-1932页

作者： shaobo Si Chenchen Sun Yufen Wu Jingjing Li han Wang Yinggang Lin Jin Yang Zhong Lin Wang Department of Optoelectronic Engineering Key Laboratory of Optoelectronic Technology and Systems Ministry of EducationChongqing UniversityChongqing 400044China College of Physics and Electronic Engineering Chongqing Normal UniversityChongqing 401331China Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of SciencesBeijing 100083China School of Materials Science and Engineering Georgia Institute of TechnologyAtlantaGA 30332USA

The performance degradation and even damage of the e-textiles caused by sweat,water,or submersion during all-weather health monitoring are the main reasons that e-textiles have not been commercialized and routinized so far.Herein,we developed an amphibious,high-performance,air-permeable,and comfortable all-textile triboelectric sensor for continuous and precise measurement of epidermal pulse waves during full-day activities.Based on the principle of preparing gas by acid-base neutralization reaction,a one-piece preparation process of amphibious conductive yarn(ACY)with densely porous structures is proposed.An innovative three-dimensional(3D)interlocking fabric knitted from ACYs(0.6 mm in diameter)and polytetrafluoroethylene yarns exhibit high sensitivity(0.433 V·kPa^(-1)),wide bandwidth(up to 10 Hz),and stability(>30,000 cycles).With these benefits,98.8%agreement was achieved between wrist pulse waves acquired by the sensor and a high-precision laser vibrometer.Furthermore,the polytetrafluoroethylene yarn with good compression resilience provides sufficient mechanical support for the contact separation of the ACYs.Meanwhile,the unique skeletonized design of the 3D interlocking structure can effectively relieve the water pressure on the sensor surface to obtain stable and accurate pulse waves(underwater depth of 5 cm).This achievement represents an important step in improving the practicality of e-textiles and early diagnosis of cardiovascular diseases.

关键词： triboelectric pressure sensor amphibious fabric interlocking fabric pulse wave measurement one-piece preparation method

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Simplistic framework of single-pixelprogrammable metasurfaces integrated with a capsuled LED array

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Photonics Research 2024年第5期12卷 884-894页

作者： YuxI LI JIAFU WANG SAI SUI RUICHAO ZHU DYAJUAN han HONGYA CHEN XINMIN FU SHAOJIE WANG CUNQIAN FENG shaobo QU Shaanxi Key Laboratory of Artificially-Structured Functional Materials and Devices Air Force Engineering UniversityXi’an 710051China Air and Missile Defense College Air Force Engineering UniversityXi’an 710051China

Coding metasurfaces can manipulate electromagnetic wave in real time with high degree of freedom,the fascinating properties of which enrich the metasurface design with a wide range of application prospects.However,most of the coding metasurfaces are designed based on external excitation framework with the wired electrical or wireless light control devices,thus inevitably causing the interference with electromagnetic wave transmission and increasing the complexity of the metasurface design.In this work,a simplistic framework of single-pixel-programmable metasurfaces integrated with a capsuled LED array is proposed to dynamically control electromagnetic wave.The framework fully embeds the photoresistor in the meta-atom,controlling the LED array to directly illuminate the photoresistor to modulate the phase response.With this manner,the complex biasing network is transformed to the universal LED array,which means the physical control framework can be transformed to a software framework,and thus the functions of the metasurface can be freely manipulated by encoding the capsuled LED array avoiding mutual coupling of adjacent meta-atoms in real time.All the results verify that the far-field scattering pattern can be customized with this singlepixel-programmable metasurface.Encouragingly,this work provides a universal framework for coding metasurface design,which lays the foundation for metasurface intelligent perception and adaptive modulation.

关键词： surface. transformed mutual

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11.2 W/mm power density AlGaN/GaN high electron-mobility transistors on a GaN substrate

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Journal of Semiconductors 2024年第1期45卷 38-41页

作者： Yansheng Hu Yuangang Wang Wei Wang Yuanjie Lv Hongyu Guo Zhirong Zhang Hao Yu Xubo Song Xingye zhou Tingting han shaobo Dun Hongyu Liu Aimin Bu Zhihong Feng National Key Laboratory of Solid-State Microwave Devices and Circuits Hebei Semiconductor Research InstituteShijiazhuang 050051China

In this letter,high power density AlGaN/GaN high electron-mobility transistors(HEMTs)on a freestanding GaN substrate are reported.An asymmetricΓ-shaped 500-nm gate with a field plate of 650 nm is introduced to improve microwave power performance.The breakdown voltage(BV)is increased to more than 200 V for the fabricated device with gate-to-source and gate-to-drain distances of 1.08 and 2.92μm.A record continuous-wave power density of 11.2 W/mm@10 GHz is realized with a drain bias of 70 V.The maximum oscillation frequency(f_(max))and unity current gain cut-off frequency(f_(t))of the AlGaN/GaN HEMTs exceed 30 and 20 GHz,respectively.The results demonstrate the potential of AlGaN/GaN HEMTs on freestanding GaN substrates for microwave power applications.

关键词： freestanding GaN substrates AlGaN/GaN HEMTs continuous-wave power density breakdown voltage Γ-shaped gate

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水泥分解炉煤/生物质耦合预热特性试验

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洁净煤技术 2023年第9期29卷 24-31页

作者：李鹏鹏任强强吕清刚王超张驰韩绍博华北电力大学能源动力与机械工程学院北京102206 中国科学院工程热物理研究所北京100190 中国科学院大学北京100049 中国科学技术大学安徽合肥230026

在干法水泥生产技术中,分解炉内燃料燃烧和原料分解对水泥质量和污染物排放有重要影响。与燃料直接注入分解炉燃烧相比,燃料经循环流化床预热处理后再注入分解炉燃烧不仅可以提高分解炉内燃烧性能,减少有害气体排放,同时预热处理也可以... 详细信息

在干法水泥生产技术中,分解炉内燃料燃烧和原料分解对水泥质量和污染物排放有重要影响。与燃料直接注入分解炉燃烧相比,燃料经循环流化床预热处理后再注入分解炉燃烧不仅可以提高分解炉内燃烧性能,减少有害气体排放,同时预热处理也可以增加水泥分解炉的燃料适应性。主要研究煤与生物质混合燃料在进入分解炉前由循环流化床预热后的预热特性,即不同因素对固相预热燃料和煤气的影响。研究表明:氧碳比(单位时间内O_(2)与C的摩尔质量比)的增大会导致预热炉内反应和颗粒碰撞更为剧烈,导致预热燃料粒径减小;同时氧碳比增加会使煤和稻壳耦合预热产生的焦炭灰分增加,其他组分减少;外热源升温可明显提升CO、CH_(4)、H_(2)等煤气有效燃烧组分的生成,提高固相燃料中各组分的转化率。

关键词：水泥分解炉生物质循环流化床燃料预热

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中药穴位贴敷神阙穴治疗儿童功能性便秘临床研究

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河北中医 2022年第8期44卷 1267-1271页

作者：游梦祺张君韩少博北京中医药大学房山医院儿科北京102400

目的观察中药穴位贴敷神阙穴治疗儿童功能性便秘的临床疗效。方法选择120例儿童功能性便秘患者,均为实证便秘,按照随机数字表法分为对照组和观察组,各60例。对照组采用双歧杆菌三联活菌散常规治疗,观察组采用中药穴位贴敷神阙穴治疗。2... 详细信息

目的观察中药穴位贴敷神阙穴治疗儿童功能性便秘的临床疗效。方法选择120例儿童功能性便秘患者,均为实证便秘,按照随机数字表法分为对照组和观察组,各60例。对照组采用双歧杆菌三联活菌散常规治疗,观察组采用中药穴位贴敷神阙穴治疗。2组均7 d为1个疗程,连续治疗2个疗程。比较2组治疗前后Bristol粪便性状分级及Cleveland便秘评分系统(CCS)、便秘患者生活质量自评量表(PAC-QOL)中文版、中医证候、便秘症状评分变化,并比较2组临床疗效、不良反应。结果治疗后,2组CCS、PAC-QOL评分和中医证候各项评分及总分、便秘症状各项评分和总分均较本组治疗前显著降低(P0.05)。结论中药穴位贴敷神阙穴治疗能有效降低儿童功能性便秘实证患儿的便秘严重程度,改善生活质量。

关键词：便秘儿童穴位贴敷法穴,神阙穴儿童功能性实证

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准噶尔盆地南缘煤型气运移机制探讨

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西安石油大学学报（自然科学版） 2017年第6期32卷 10-19,28页

作者：韩少博徐国盛宋占东成都理工大学油气藏地质及开发工程国家重点实验室四川成都610059 中国石油大学(北京)盆地与油藏研究中心北京102249

依据天然气δ13C2数值把准南煤型气划分为A组和B组。A组煤型气主要分布在安集海背斜以西的第三排构造带,B组煤型气主要分布在安集海背斜以东,包括准南的三排构造带;根据水溶气和游离气的组分运移特征,结合准南地层压力、地层水矿化度和... 详细信息

依据天然气δ13C2数值把准南煤型气划分为A组和B组。A组煤型气主要分布在安集海背斜以西的第三排构造带,B组煤型气主要分布在安集海背斜以东,包括准南的三排构造带;根据水溶气和游离气的组分运移特征,结合准南地层压力、地层水矿化度和重碳酸根浓度,提出A组煤型气为水溶气运移,B组煤型气以游离气运移为主;异常压力是水溶气向上运移的动力,构造应力控制了煤型气的运移方式,应力强烈的第一排构造带以游离气运移为主,应力较弱的第三排构造带以水溶气运移为主,第二排构造带上煤型气两种运移方式都存在;煤型气i-C4/n-C4和i-C5/n-C5值显示运移通道为构造微裂缝或短暂开启的断层,运移的水动力较强。

关键词：非常规天然气煤型气运移机制准噶尔盆地南缘水溶气游离气地层压力

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自适应免疫粒子群算法在光伏MPPT中的应用

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电源技术 2024年第4期48卷 749-754页

作者：李练兵王兰超朱乐韩琪琪杨少波河北工业大学电气工程学院天津300130 河北工业大学人工智能与数据科学学院天津300130 国网河北省电力有限公司电力科学研究院河北石家庄050000

光伏阵列在局部遮阴条件下,其P-U特性曲线呈多峰特性,传统的最大功率点跟踪(MPPT)算法容易陷入局部最优,而无法追踪到最大功率点。粒子群(PSO)算法适用于复杂多极值的寻优问题,因而在多峰值MPPT中得到广泛应用。针对粒子群算法寻优过程... 详细信息

光伏阵列在局部遮阴条件下,其P-U特性曲线呈多峰特性,传统的最大功率点跟踪(MPPT)算法容易陷入局部最优,而无法追踪到最大功率点。粒子群(PSO)算法适用于复杂多极值的寻优问题,因而在多峰值MPPT中得到广泛应用。针对粒子群算法寻优过程中易早熟收敛至局部最优、迭代后期收敛速度慢以及精度低等问题,提出了一种自适应免疫粒子群算法。该算法对惯性权重和学习因子进行自适应调整,并且与免疫算法相结合。仿真结果表明:该算法在静态局部遮阴以及动态局部遮阴条件下,均能追踪到最大功率点,并且收敛速度更快,精度更高,稳定性更好。

关键词：光伏电池局部遮阴 MPPT 自适应免疫粒子群算法

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