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Geochemical Characteristics and Origin of Nuanquanzi Geothermal Water in Yudaokou,Chengde,Hebei,North China

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Journal of Earth Science 2023年第3期34卷 838-856页

作者： Houyun sun Xiaoming Sun Xiaofeng Wei Xingkai Huang Guoqiu Ke Hao Wei School of Water Resources&Environment China University of GeosciencesBeijing 100083China Beijing Institute of Geology for Mineral Resources Co. Ltd.Beijing 100012China China Institute of Geo-Environment Monitoring Beijing 100081China Zhongse Jietai Geophysical Science Co. Ltd.Beijing 100012China Hebei Center for Ecological and Environmental Geology Research Hebei GEO UniversityShijiazhuang 050031China

Study on the Nuanquanzi geothermal field in the Yanshan uplift is of great significance for understanding the origin of geothermal fluid in the intracontinental orogenic belt of the fault depression basin margin in North China.The geochemical characteristics and formation mechanism of the Nuanquanzi geothermal system were elucidated by classical hydrogeochemical analysis,multi-isotopes approach(δD,δ^(18)O,δ^(13)C,δ^(87)Sr/^(86)Sr),14CAMSdating,and integrated geophysical prospecting of surface-soil radon gas measurement and CSAMT inversion.The results show that the Nuanquanzi geothermal field is a medium-low temperature convection-fault semi-enclosed geothermal system.The hydrochemical type of thermal water is primarily HCO_(3)-Na,and rich in soluble SiO_(2),F^(-)and Cl^(-).The geothermal water primarily originated from the recharging meteoric water with a maximum circulation depth of 2400-3200 m,but affected by the mixing of endogenous sedimentary water.The reservoir temperature calculated by Na-K and quartz geothermometer of the Nuanquanzi geothermal system was determined to be 73.39-92.87℃.The conduction-cooling and shallow cold-water mixing processes occurred during the parent geothermal fluid ascent to surface,and the proportion of cold-water mixing during circulation was approximately 88.3%to 92.2%.The high-anomaly radon zones matched well to the low apparentresistance areas and hiding faults,indicating that the Nuanquanzi geothermal field was dominated by a graben basin restricted by multiple faults.

关键词： geothermal water hydrogeochemistry water isotopes soil radon measurement controlled source audio-frequency magnetotelluric

Exact quantum query complexity of weight decision problems via Chebyshev polynomials

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Science China(Information Sciences) 2023年第2期66卷 297-298页

作者： Xiaoyu HE Xiaoming Sun Guang YANG Pei YUAN Institute of Computing Technology Chinese Academy of Sciences (CAS) University of Chinese Academy of Sciences

The weight decision problem, which requires determining the Hamming weight of a given binary string, is a natural and important problem with lots of applications, such as cryptanalysis [1] and coding theory. In this study, we investigate the exact quantum query complexity of weight decision problems, where the exact quantum algorithm must always output the correct answer within finite steps(see Appendix A for a detailed explanation).

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Phosphorus induced activity-enhancement of Fe-N-C catalysts for high temperature polymer electrolyte membrane fuel cells

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Nano Research 2023年第5期16卷 6531-6536页

作者： Xiangrong Jin Yajie Li Hao sun Xiangxiang Gao Jiazhan Li Zhi Lü Wen Liu Xiaoming Sun State Key Laboratory of Chemical Resource Engineering College of ChemistryBeijing University of Chemical TechnologyBeijing 100029China Engineering Research Center of Advanced Rare Earth Materials Department of ChemistryTsinghua UniversityBeijing 100084China

Fe-N-C materials with atomically dispersed Fe–N_(4) sites could tolerate the poisoning of phosphate,is regarded as the most promising alternative to costly Pt-based catalysts for the oxygen reduction in high temperature polymer electrolyte membrane fuel cells(HT-PEMFCs).However,they still face the critical issue of insufficient activity in phosphoric acid.Herein,we demonstrate a P-doping strategy to increase the activity of Fe-N-C catalyst via a feasible one-pot method.X-ray absorption spectroscopy and electron microscopy with atomic resolution indicated that the P atom is bonded with the N in Fe–N_(4) site through C atoms.The as prepared Fe-NCP catalyst shows a half-wave potential of 0.75 V(vs.reversible hydrogen electrode(RHE),0.1 M H_(3)PO_(4)),which is 60 and 40 mV higher than that of Fe-NC and commercial Pt/C catalysts,respectively.More importantly,the Fe-NCP catalyst could deliver a peak power density of 357 mW·cm^(−2)in a high temperature fuel cell(160℃),exceeding the non-noble-metal catalysts ever reported.The enhancement of activity is attributed to the increasing charge density and poisoning tolerance of Fe–N_(4) caused by neighboring P.This work not only promotes the practical application of Fe-N-C materials in HT-PEMFCs,but also provides a feasible P-doping method for regulating the structure of single atom site.

关键词： iron nitrogen carbon heteroatomic doping phosphorous tolerance high temperature polymer electrolyte membrane fuel cells

Current Status and Perspectives of Dual-Atom Catalysts Towards Sustainable Energy Utilization

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Nano-Micro Letters 2024年第7期16卷 402-440页

作者： Yizhe Li Yajie Li Hao sun Liyao Gao Xiangrong Jin Yaping Li Zhi LV Lijun Xu Wen Liu Xiaoming Sun State Key Laboratory of Chemical Resource Engineering Beijing Advanced Innovation Center for Soft Matter Science EngineeringCollege of ChemistryBeijing University of Chemical TechnologyBeijing 100029People’s Republic of China Xinjiang Coal Mine Mechanical and Electrical Engineering Technology Research Center Xinjiang Institute of EngineeringUrumqi 830023Xinjiang Uygur Autonomous RegionPeople’s Republic of China

The exploration of sustainable energy utilization requires the imple-mentation of advanced electrochemical devices for efficient energy conversion and storage,which are enabled by the usage of cost-effective,high-performance electro-catalysts.Currently,heterogeneous atomically dispersed catalysts are considered as potential candidates for a wide range of applications.Compared to conventional cata-lysts,atomically dispersed metal atoms in carbon-based catalysts have more unsatu-rated coordination sites,quantum size effect,and strong metal-support interactions,resulting in exceptional catalytic activity.Of these,dual-atomic catalysts(DACs)have attracted extensive attention due to the additional synergistic effect between two adja-cent metal atoms.DACs have the advantages of full active site exposure,high selectiv-ity,theoretical 100%atom utilization,and the ability to break the scaling relationship of adsorption free energy on active sites.In this review,we summarize recent research advancement of DACs,which includes(1)the comprehensive understanding of the synergy between atomic pairs;(2)the synthesis of DACs;(3)characterization meth-ods,especially aberration-corrected scanning transmission electron microscopy and synchrotron spectroscopy;and(4)electrochemical energy-related applications.The last part focuses on great potential for the electrochemical catalysis of energy-related small molecules,such as oxygen reduction reaction,CO_(2) reduction reaction,hydrogen evolution reaction,and N_(2) reduction reaction.The future research challenges and opportunities are also raised in prospective section.

关键词： Dual-atom catalysts Synergetic effect Electrocatalysis Oxygen reduction reaction CO_(2)reduction reaction Hydrogen evolution reaction N2 reduction reaction

Energy absorption characteristics of novel high-strength and hightoughness steels used for rock support

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第6期15卷 1441-1456页

作者： Ding Wang Manchao He Liangjiu Jia Xiaoming Sun Min Xia Xuchun Wang State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyBeijing100083China Research Institute for Deep Underground Science and Engineering China University of Mining and TechnologyBeijing100083China Department of Disaster Mitigation for Structures School of Civil EngineeringTongji UniversityShanghai200092China State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai200092China Department of Geotechnical Engineering School of Civil EngineeringTongji UniversityShanghai200092China School of Civil Engineering Qingdao University of TechnologyQingdao266033China

Nowadays,the development of novel metallic materials for rock support have attracted research interests since they can significantly improve the deformation and energy absorption capacities of rock bolts.Although previous studies proved the importance and mechanical advantages of utilizing high-strength and high-toughness(HSHT)steels in rock support,there is no systematic analysis to reveal the essential energy absorption parameter and the guidelines for further development of metallic rock support materials.This paper analyzes the energy absorption characteristics of novel HSHT steels(negative Poisson’s ratio(NPR)and twinning-induced plasticity(TWIP)steels)in comparison with conventional rock support materials.A physically based crystal plasticity(CP)model was set up and calibrated to study the effect of strain hardening rate(SHR).Meanwhile,the roles of underlying physical mechanisms,i.***.the dislocation density and twin volume fraction,were studied.The results show that the improvement of energy absorption density(EAD)is essential for further development of rock support materials,besides the increase of energy absorption rate(EAR)for previous development of conventional rock support materials.The increase of EAD requires increases of both strength and deformation capacity of materials.For HSHT steels,the decrease of SHR has a positive effect on the improvement of EAD.In addition,the increase of EAD is followed by the increase of twin volume fraction and the decrease of plastic Poisson’s ratio which can promote deformation plasticity of materials.Meanwhile,the increase of EAR is correlated with the accumulation of dislocation density,which can increase the strength of materials.This paper provides the theoretical basis and guidelines for developing rock support materials in deep underground engineering and other related fields.

关键词： Rock support Steel Energy absorption Strain hardening rate(SHR) Crystal plasticity(CP)

A Quasi-Linear Relationship between Planetary Outgoing Longwave Radiation and Surface Temperature in a Radiative-Convective-Transportive Climate Model of a Gray Atmosphere

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Advances in Atmospheric Sciences 2024年第1期41卷 8-18页

作者： Jie sun Michael SECOR Ming CAI xiaoming HU Department of Earth Oceanand Atmospheric ScienceFlorida State UniversityTallahasseeFlorida 32304USA School of Atmospheric Sciences Sun Yat-sen University and Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies Zhuhai 519082China

In this study,we put forward a radiative-convective-transportive energy balance model of a gray atmosphere to examine individual roles of the greenhouse effect of water vapor,vertical convection,and atmospheric poleward energy transport as well as their combined effects for a quasi-linear relationship between the outgoing longwave radiation(OLR)and surface temperature(T_(S)).The greenhouse effect of water vapor enhances the meridional gradient of surface temperature,thereby directly contributing to a quasi-linear OLR-T_(S) relationship.The atmospheric poleward energy transport decreases the meridional gradient of surface temperature.As a result of the poleward energy transport,tropical(high-latitude)atmosphere-surface columns emit less(more)OLR than the solar energy input at their respective locations,causing a substantial reduction of the meridional gradient of the OLR.The combined effect of reducing the meridional gradients of both OLR and surface temperature by the poleward energy transport also contributes to the quasi-linear OLR-T_(S) relationship.Vertical convective energy transport reduces the meridional gradient of surface temperature without affecting the meridional gradient of OLR,thereby suppressing part of the reduction to the increasing rate of OLR with surface temperature by the greenhouse effect of water vapor and poleward energy transport.Because of the nature of the energy balance in the climate system,such a quasi-linear relationship is also a good approximation for the relationship between the annual-mean net downward solar energy flux at the top of the atmosphere and surface temperature.

关键词： outgoing longwave radiation greenhouse effect poleward energy transport

Null-free False Discovery Rate Control Using Decoy Permutations

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Acta Mathematicae Applicatae Sinica 2022年第2期38卷 235-253页

作者： Kun He Mengjie Li Yan Fu Fuzhou Gong Xiaoming Sun Institute of Computing Technology Chinese Academy of SciencesBeijing 100190China CEMS NCMISRCSDSAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

The traditional approaches to false discovery rate(FDR)control in multiple hypothesis testing are usually based on the null distribution of a test statistic.However,all types of null distributions,including the theoretical,permutation-based and empirical ones,have some inherent drawbacks.For example,the theoretical null might fail because of improper assumptions on the sample distribution.Here,we propose a null distributionfree approach to FDR control for multiple hypothesis testing in the case-control study.This approach,named target-decoy procedure,simply builds on the ordering of tests by some statistic or score,the null distribution of which is not required to be known.Competitive decoy tests are constructed from permutations of original samples and are used to estimate the false target discoveries.We prove that this approach controls the FDR when the score function is symmetric and the scores are independent between different tests.Simulation demonstrates that it is more stable and powerful than two popular traditional approaches,even in the existence of dependency.Evaluation is also made on two real datasets,including an arabidopsis genomics dataset and a COVID-19 proteomics dataset.

关键词： multiple testing false discovery rate null distribution-free p-value-free decoy permutations knockoff filter

High throughput screening of single atomic catalysts with optimized local structures for the electrochemical oxygen reduction by machine learning

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Journal of Energy Chemistry 2023年第6期81卷 349-357,I0009页

作者： Hao sun Yizhe Li Liyao Gao Mengyao Chang Xiangrong Jin Boyuan Li Qingzhen Xu Wen Liu Mingyue Zhou Xiaoming Sun State Key Laboratory of Chemical Resource Engineering College of ChemistryBeijing University of Chemical TechnologyBeijing 100029China Beijing Key Laboratory of Green Chemical Reaction Engineering and Technology Department of Chemical EngineeringTsinghua UniversityBeijing 100084China

Single atomic catalysts(SACs),especially metal-nitrogen doped carbon(M-NC)catalysts,have been extensively explored for the electrochemical oxygen reduction reaction(ORR),owing to their high activity and atomic utilization efficiency.However,there is still a lack of systematic screening and optimization of local structures surrounding active centers of SACs for ORR as the local coordination has an essential impact on their electronic structures and catalytic performance.Herein,we systematic study the ORR catalytic performance of M-NC SACs with different central metals and environmental atoms in the first and second coordination sphere by using density functional theory(DFT)calculation and machine learning(ML).The geometric and electronic informed overpotential model(GEIOM)based on random forest algorithm showed the highest accuracy,and its R^(2) and root mean square errors(RMSE)were 0.96 and 0.21,respectively.30 potential high-performance catalysts were screened out by GEIOM,and the RMSE of the predicted result was only 0.12 V.This work not only helps us fast screen high-performance catalysts,but also provides a low-cost way to improve the accuracy of ML models.

关键词： Single atomic catalysts Coordination sphere High throughput screening Machine learning Oxygen reduction reaction

Surface hydrophobic modification enhanced catalytic performance of electrochemical nitrogen reduction reaction

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Nano Research 2022年第5期15卷 3886-3893页

作者： Lijuan Niu Ziwen Liu Guohua Liu Mengxuan Li Xupeng Zong Dandan Wang Li An Dan Qu Xiaoming Sun Xiayan Wang Zaicheng sun Beijing Key Laboratory for Green Catalysis and Separation Center of Excellence for Environmental Safety and Biological EffectsFaculty of Environment and LifeBeijing University of TechnologyBeijing 100124China State Key Laboratory of Chemical Resource Engineering College of Energy Beijing Advanced Innovation Center for Soft Matter Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029China Key Laboratory of Functional Materials Physics and Chemistry of the Ministry of Education Jilin Normal UniversityChangchun 130103China

Electrocatalytic nitrogen reduction reaction(NRR)is a sustainable approach for NH_(3)production with low energy consumption.However,competing hydrogen reduction reaction(HER)in aqueous solution results in low NH_(3)production and Faraday efficiency(FE).Here,MoS_(2)nanostructures with a hydrophobic surface are synthesized by alkyl thiols modification.Aerophilic and hydrophobic surface facilitates an efficient three-phase contact of N_(2),H_(2)O,and catalyst.Thus,localized concentrated N_(2)molecules can overcome the mass transfer limitation of N2 and depress the HER due to lowering the proton contacts.Although the active-sites decrease with the increase of the alkyl chain since the thiol may cover the active site,the optimized electrocatalyst achieves NH_(3)yield of 12.86×10^(-11)mol·cm^(-2)·s^(-1)at-0.25 V and 22.23%FE,which are 4.3 and 24 times higher than those of MoS2-CP electrocatalyst,respectively.The increased catalytic performance is attributed to the high N_(2)adsorption and depressed HER.

关键词： nitrogen reduction reaction MoS_(2)electrocatalyst hydrophobic modification density functional theory calculations