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Boosting oxygen vacancies by modulating the morphology of Au decorated In_(2)O_(3)with enhanced CO_(2)hydrogenation activity to CH_(3)OH

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Journal of Environmental Sciences 2024年第6期140卷 91-102页

作者： Ruxian Hou Jiewen Xiao Qian Wu tianyu zhang Qiang Wang Beijing Key Lab for Source Control Technology of Water Pollution College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China Engineering Research Center for Water Pollution Source Control&Eco-remediation College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China

CO_(2)hydrogenation to methanol has become one of the most promising ways for CO_(2)utilization,however,the CO_(2)conversion rate and methanol selectivity of this reaction still need to be improved for industrial *** we investigated the structure-activity relationship for CO_(2)conversion to methanol of In_(2)O_(3)-based catalysts by modulating morphology and decorating *** different Au/In_(2)O_(3)catalysts were prepared,their activity follow the sequence of Au/In_(2)O_(3)-nanosphere(Au/In_(2)O_(3)-NS)>Au/In_(2)O_(3)-nanoplate(Au/In_(2)O_(3)-NP)>Au/In_(2)O_(3)-hollow microsphere(Au/In_(2)O_(3)-HM).Au/In_(2)O_(3)-NS exhibited the best performance with good CO_(2)conversion of 12.7%,high methanol selectivity of 59.8%,and large space time yield of 0.32 g CH_(3)OH/(hr·gcat)at 300℃.The high performance of Au/In_(2)O_(3)-NS was considered as the presence of *** contributes to the creation of more surface oxygen vacancies,which further promoted the CO_(2)adsorption and facilitated CO_(2)activation to form the formate intermediates towards *** work clearly suggests that the activity of In_(2)O_(3)catalyst can be effective enhanced by structure engineering and Au decorating.

关键词： CO_(2)hydrogenation Methanol Au/In_(2)O_(3) Morphology Oxygen vacancies

Evaluation and Projection of Extreme High Temperature Indices in Southwestern China Using NEX-GDDP-CMIP6

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Journal of Meteorological Research 2024年第1期38卷 88-107页

作者： Fen zhang Linxiao WEI Yonghua LI Hongyu TANG tianyu zhang Baogang YANG China Meteorological Administration Key Open Laboratory of Transforming Climate Resource to Economy Chongqing Climate CentreChongqing 401147

Based on the recently released NASA Earth Exchange Global Daily Downscaled Projections(NEX-GDDP)Coupled Model Intercomparison Project Phase 6(CMIP6) dataset and the gridded observational daily dataset CN05.1, this study evaluates the performance of 26 CMIP6 models in simulating extreme high temperature(EHT) indices in southwestern China and estimates future changes in the EHT indices under the Shared Socioeconomic Pathways(SSPs) SSP1-2.6, SSP2-4.5, and SSP5-8.5 using 11 optimal CMIP6 models. Five EHT indices are employed:annual maximum value of daily maximum temperature(TXX), high temperature days(T35), warm days(TX90P),heat wave frequency(HWF), and heat wave days(HWD). The main results are as follows.(1) NEX-GDDP-CMIP6 is highly capable of simulating the spatial patterns of TXX and T35 in southwestern China but it presents a weaker ability to simulate the spatial patterns of TX90P, HWF, and HWD.(2) The simulated time series of T35, TX90P, HWF,and HWD in southwestern China exhibit consistent upward trends with the observations. The linear trends of increase in TX90P and HWD are much greater than those of increase in TXX, T35, and HWF.(3) The estimated increases in TXX and T35 in southwestern China are significantly greater in Chongqing and the adjacent areas of Sichuan than in the other regions. Spatial distributions of the increases in TX90P, HWF, and HWD generally show higher values in the west and lower values in the east.(4) In the three different scenarios, the projected future TXX,T35, TX90P, and HWD in southwestern China all display a continuous increase with time and radiative forcing levels, whereas HWF initially increases but then decreases under the SSP5-8.5 scenario. By the end of the 21st century, under the SSP5-8.5 scenario, TXX and T35 are projected to increase by 6.0℃ and 45.0 days, respectively. The duration of individual heat waves is also expected to increase.

关键词： NEX-GDDP-CMIP6 extreme high temperature(EHT) southwestern China evaluation projection

Hovering rotor aerodynamics in extreme ground effect

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Chinese Journal of Aeronautics 2024年第7期37卷 204-219页

作者： Zhenlong WU tianyu zhang Huijun TAN Haoyu ZHOU Wei CHEN Maixiang XIE College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China China Aviation Power Machinery Research Institute Zhuzhou 412002China

This paper presents an experimental and numerical study of the aerodynamics of a moderate-scale rotor hovering in the Extreme Ground Effect(EGE)where rotor height-offground is below half the rotor *** tip vortex field was visualized by using the PIV *** aerodynamic performance,tip vortex trajectory,wall jet characteristics,surface pressure and velocity fields were measured and *** explore more deeply the flow mechanisms of the extreme ground effect,Detached Eddy Simulation(DES)was conducted on completely structured *** results showed significant deviations of the rotor performance in EGE from that in Regular Ground Effect(RGE)with the rotor heights of more than half the rotor ***,the flow structures of the rotor in EGE are considerably complex,such as the wall jet and groundwash flow *** rotor wake flow and tip vortices impact the ground more frequently,resulting in distinctive characteristics of the surface pressure and velocity fields in EGE.

关键词： Rotor Ground effect Tip vortex Detached Eddy Simulation(DES) Groundwash

Deformation characteristics and damage ontologies of soft and hard composite rock masses under impact loading

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Journal of Mountain Science 2024年第5期21卷 1715-1727页

作者： LI Jinhua zhang tianyu WU Baolin SU Peili YANG Yang WANG Pan Architectural and Civil Engineering College Xi’an University of Science and TechnologyXi’an 710054China

As one of the most common occurring geological landforms in deep rock formations, the dynamic mechanical properties of layered composite rock bodies under impact loading have been widely studied by scholars. To study the dynamic properties of soft and hard composite rocks with different thickness ratios, this paper utilizes cement, quartz sand and gypsum powder to construct soft and hard composite rock specimens and utilizes a combination of indoor tests, numerical calculations, and theoretical analyses to investigate the mechanical properties of soft and hard composite rock bodies. The test results reveal that:(1) When the proportion of hard rock increases from 20% to 50%, the strength of the combined rock body increases by 69.14 MPa and 87 MPa when the hard rock face and soft rock face are loaded, respectively;however, when the proportion of hard rock is the same, the compressive strength of the hard rock face impact is 9%-17% greater than that of the soft rock face impact;(2) When a specimen of soft and hard combined rock body is subjected to impact loading, the damage mode involves mixed tension and shear damage, and the cracks generally first appear at the ends of the specimen, then develop on the laminar surface from the impact surface, and finally end in the overall damage of the soft rock part. The development rate and the total number of cracks in the same specimen when the hard rock face is impacted are significantly greater than those when the soft rock face is impacted;(3) By introducing Weibull’s statistical strength theory to establish the damage variables of soft-hard combined rock bodies, combined with the DP strength criterion, the damage model and the Kelvin body are concatenated to obtain a statistical damage constitutive model, which can better fit the full stress-strain curve of soft-hard combined rock body specimens under a single impact load.

关键词： Soft and hard composite rock mass Dynamic properties Split Hopkinson pressure bar(SHPB) Numerical simulation Intrinsic damage model

Yolk-shell FeCu/NC electrocatalyst boosting high-performance zinc-air battery

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Nano Research 2024年第9期17卷 7918-7925页

作者： Chen Liang tianyu zhang Shilun Sun Aijuan Han Zenghui Qiu Haijun Xu Junfeng Liu State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China College of Mathematics&Physics Beijing University of Chemical TechnologyBeijing 100029China Beijing Bioprocess Key Laboratory Beijing University of Chemical TechnologyBeijing 100029China

Iron-nitrogen-carbon single-atom catalysts(Fe-N-C SACs)are widely acknowledged for their effective oxygen reduction activity,however,their activity requires further ***,additional structural optimization is necessary to enhance mass transport and achieve higher power density in practical ***,using ZIF-8 as a template,we synthesized yolk-shell catalysts featuring complex sites of Fe single atoms and Cu nanoclusters(y-FeCu/NC)via partial etching and liquid-phase *** synthesized y-FeCu/NC catalyst exhibits high specific surface area and mesoporous *** with the advantages of highly active sites and yolk-shell structure,the y-FeCu/NC catalyst demonstrated outstanding catalytic performance in the oxygen reduction reaction,achieving a half-wave potential(E_(1/2))of 0.97 V in 0.1 M *** a practical energy device,Zn-air battery(ZAB)assembled with y-FeCu/NC catalyst achieved a remarkable power density of 356.3 mW·cm^(-2),representing an improvement of approximately 28.5%compared to its solid FeCu/NC ***,it showcased impressive stability,surpassing all control samples.

关键词： atomic Fe-N4 sites Cu nanoclusters yolk-shell structure oxygen reduction reaction zinc-air battery

Thienothiophene-centered ladder-type π-systems that feature distinct quinoidal π-extension

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Chinese Chemical Letters 2024年第5期35卷 249-253页

作者： Jiaxiang Guo Zeyi Li tianyu zhang Xinyu Tian Yue Wang Chuandong Dou State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin UniversityChangchun 130012China Jiangsu Engineering Laboratory of Novel Functional Polymeric Materials Soochow UniversitySuzhou 215123China

Quinoidalπ-conjugated structures,a kind of fundamental subunits for organicπ-systems,may produce some intriguing optical,electronic and magnetic properties of polycyclic hydrocarbons(PHs).Herein,we report two thienothiophene-centered ladder-type polycyclic molecules(1 and 2),which possess one quinoidal thienothiophene moiety and two para-quinodimethane(p-QDM)subunits,*** theoretically and experimentally studied,while 1 is a fully closed-shell molecule,2 owns an open-shell structure along with partial contribution of tetraradical state that is induced by the resonance of ***,although 2 has a largerπ-conjugated skeleton and open-shell electronic state,it exhibits larger bandgap and blue-shifted *** the other hand,the reversible oxidation activity of 1 enables the preparation of its dication 1^(2+),and the studies on its single-crystal and aromatic structures demonstrate that its two positive charges are delocalized onto the oxygen atoms,thus achieving fullyπ-extended structure and near-infrared *** study not only gains insight into quinoidalπ-subunits,but also provides an important basis for the development of antiaromatic and open-shellπ-electron materials.

关键词： Thienothiophene Quinoidal conjugation Open-shell structure Aromaticity Photophysical properties

50-110 GHz,high isolation,and high-power linearity single-pole double-throw switch utilizing 100-nm GaN HEMT technology

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The Journal of China Universities of Posts and Telecommunications 2024年第2期31卷 38-43,71页

作者： Han Qunfei Hu Sanming zhang tianyu Chen Qing Shen Yizhu Wang Weibo Tao Hongqi School of Information Science and Engineering Southeast UniversityNanjing 210096China Nanjing Electronic Devices Institute Nanjing 210016China State Key Laboratory of Millimeter Waves Southeast UniversityNanjing 210096China

This article presents the design and performance of a single-pole double-throw(SPDT)switch operating in 50-110 *** switch is fabricated in a 100-nm GaN high-electron-mobility transistors(HEMT)*** realize high-power capability,the dimensions of GaN HEMTs are selected by simulation *** enhance the isolation,an improved structure of shunt HEMT with two ground holes is *** extend the operation bandwidth,the SPDT switch with multi-section resonant units is proposed and *** verify the SPDT switch design,a prototype operating in 50-110 GHz is *** measured results show that the fabricated SPDT switch monolithic microwave integrated circuit(MMIC)achieves an input 1 dB compression point(P_(1dB))of 38 dBm at 94 GHz,and isolation within the range of 33 dB to 54 dB in 50-110 *** insertion loss of the switch is less than 2.1 dB,while the voltage standing wave ratios(VSWR)of the input port and output port are both less than 1.8 in the operation *** on the measured results,the presented SPDT switch MMIC demonstrates high power capability and high isolation compared with other reported millimeter-wave SPDT MMIC designs.

关键词： GaN high-electron-mobility transistors(HEMT) millimeter-wave single-pole double-throw(SPDT) switch

Parameterization, sensitivity, and uncertainty of 1-D thermodynamic thin-ice thickness retrieval

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Acta Oceanologica Sinica 2024年第7期43卷 93-111页

作者： tianyu zhang Mohammed Shokr Zhida zhang Fengming Hui Xiao Cheng Zhilun zhang Jiechen Zhao Chunlei Mi School of Geospatial Engineering and Science Sun Yat-Sen University/Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Key Laboratory of Comprehensive Observation of Polar Environment(Sun Yat-Sen University) Ministry of EducationZhuhai 519082China State Key Laboratory of Remote Sensing Science College of Global Change and Earth System ScienceBeijing Normal UniversityBeijing 100875China Science and Technology Branch Environment and Climate Change CanadaToronto M3H5T4Canada Qingdao Innovation and Development Base(Centre) Harbin Engineering UniversityQingdao 266500China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China

Retrieval of Thin-Ice Thickness(TIT)using thermodynamic modeling is sensitive to the parameterization of the independent variables(coded in the model)and the uncertainty of the measured input *** article examines the deviation of the classical model’s TIT output when using different parameterization schemes and the sensitivity of the output to the ice ***,it estimates the uncertainty of the output in response to the uncertainties of the input *** parameterized independent variables include atmospheric longwave emissivity,air density,specific heat of air,latent heat of ice,conductivity of ice,snow depth,and snow *** input parameters include air temperature,ice surface temperature,and wind *** the independent variables,the results show that the highest deviation is caused by adjusting the parameterization of snow conductivity and depth,followed ice *** sensitivity of the output TIT to ice thickness is highest when using parameterization of ice conductivity,atmospheric emissivity,and snow conductivity and *** retrieved TIT obtained using each parameterization scheme is validated using in situ measurements and satellite-retrieved *** in situ measurements,the uncertainties of the measured air temperature and surface temperature are found to be *** resulting uncertainties of TIT are evaluated using perturbations of the input data selected based on the probability distribution of the measurement *** results show that the overall uncertainty of TIT to air temperature,surface temperature,and wind speed uncertainty is around 0.09 m,0.049 m,and−0.005 m,respectively.

关键词： Arctic sea ice 1-D thermodynamic ice model thin-ice thickness sea ice parameterization

Ultrasound-assisted isolation:A new method to isolate stromal vascular fraction

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Chinese Journal of Plastic and Reconstructive Surgery 2024年第1期6卷 8-15页

作者： Yiming Gao Xiaojie zhang Poh-Ching Tan Yun Xie Peiqi zhang tianyu zhang Qingfeng Li Shuangbai Zhou Department of Plastic and Reconstructive Surgery Shanghai Ninth People’s HospitalShanghai Jiao Tong University School of MedicineShanghai200011China Department of Burns and Plastic Surgery Shanghai Changzheng HospitalShanghai200003China College of Life Sciences Shanghai Normal UniversityShanghai200233China

Background:The stromal vascular fraction(SVF),a cluster of stem and progenitor cells isolated from adipose tissue,holds significant promise for application in regenerative ***,the existing methods for SVF isolation are time-consuming and ***,in this study,we explored a new method of SVF extrac-tion-ultrasound-assisted SVF isolation(USASI)-and compared the viability and characteristics of SVF isolated using different ***:SVF extraction methods using different combinations of ultrasound power,ultrasound time,collagenase dosage,and collagenase digestion time were compared with those of the control group(collagenase digestion method).The cell yield and vitality of the SVF were evaluated via cell counting and trypan blue *** cell components and immunophenotypes of freshly isolated SVF were analyzed using flow *** prolifer-ative capacity and differentiation potential of the SVF were also ***:Ultrasonication at 95 W-20 kHz for 30 s followed by digestion with 0.15%collagenase for 30 min was identified as the most suitable parameter for the USASI method in isolating SVF,as recommended based on the evaluation of various tested *** USASI method significantly reduced the collagenase dosage and shortened the digestion *** to the collagenase digestion method,the USASI method had a higher cell yield and cell viability,with no adverse effects on cell components,proliferative capacity,or multipotential differentiation ***:With reduced processing time,lower collagenase dosage,and increased cell yield without impairing the viability and characteristics of SVF,USASI holds the potential to emerge as a time-saving and cost-effective method for future clinical applications.

关键词： Stromal vascular fractions SVF isolation Mechanical force Ultrasound