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The density of surface ligands regulates the luminescence of thiolated gold nanoclusters and their metal ion response

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Chinese Chemical Letters 2021年第8期32卷 2390-2394页

作者： Jie Xu Juanmin Li wencheng zhong Mengyao Wen Gleb Sukhorukov Li Shang State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene(NPU)Xi'an 710072China NPU-QMUL Joint Research Institute of Advanced Materials and Structures(JRI-AMAS) Northwestern Polytechnical UniversityXi'an 710072China Materials Research Institute School of Engineering and Materials ScienceQueen Mary University of LondonLondon E14NSUnited Kingdom

The fascinating luminescence properties of gold nanoclusters(AuNCs) have drawn considerable research interests,and been widely harnessed for a wide range of applications.However,a fundamental understanding towards ligand density’s role in the luminescence properties of these ultrasmall AuNCs remains unclear yet.In this communication,through systematic investigation of surface chemistries of glutathione-protected Au NCs(GSH-Au NCs) with diffe rent density of GSH as well as other thiolates,it is discovered that the density of surface ligands can significantly regulate the luminescence properties of AuNCs.Fluorescence lifetime spectroscopy and X-ray photoelectron spectroscopy showed that AuNCs with a higher density of electron-rich ligands facilitate their luminescence generation.Moreover,differences in the surface coverage of AuNCs can also affect their interactions with foreign species,as illustrated by significantly different fluorescence quenching capability of GSH-AuNCs with different ligand density towards Hg^(2+).This study provides new insight into the intriguing luminescence properties of metal NCs,which is hoped to stimulate further research on the design of metal NCs with strong luminescence and sensitive/specific responses for promising optoelectronic,sensing and imaging applications.

关键词： Gold nanoclusters Luminescence enhancement Ligand density Thermal treatment Metal ion

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一种面向航空发动机数学模型的新型修正方法

航空动力学报 2023年第11期38卷 2776-2784页

作者：钟文城汪勇宋劼张海波南京航空航天大学能源与动力学院南京210016

为了建立高置信度的航空发动机热力性能模型,以准确掌握发动机的性能变化,实现航空发动机非设计性能的高精度预测,提出了一种面向航空发动机数学模型的新型修正方法。在对发动机部件特性线平移和缩放的基础上,考虑旋转自由度,达到对压... 详细信息

为了建立高置信度的航空发动机热力性能模型,以准确掌握发动机的性能变化,实现航空发动机非设计性能的高精度预测,提出了一种面向航空发动机数学模型的新型修正方法。在对发动机部件特性线平移和缩放的基础上,考虑旋转自由度,达到对压气机特性线旋转调整的目的。引入非线性缩放因子函数与旋转因子函数以实现在不同的工况下适应性调节压气机特性数据。基于某型涡轴发动机,开展模型修正方法仿真验证。仿真结果表明:相比于仅考虑平移与缩放双自由度的模型修正方法,所提出的考虑平移、缩放与旋转的三自由度修正方法能使模型稳态平均误差从0.901%降至0.344%,大功率变化下的模型动态平均误差从1.295%降至0.889%,模型稳动态整体修正效果分别提升了62.99%和31.31%,可满足航空发动机数学模型的高精度要求。

关键词：航空发动机数学模型模型修正部件特性粒子群优化旋转自由度

Summer extreme precipitation patterns and synoptic-scale circulation precursors over the Tibetan Plateau

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Science China Earth Sciences 2024年第5期67卷 1625-1638页

作者： Zhiyuan DING Yao HA zhong zhong College of Meteorology and Oceanography National University of Defense TechnologyChangsha 410073China Key Laboratory for Virtual Geographic Environment School of Geography ScienceNanjing Normal UniversityNanjing 210023China Jiangsu Collaborative Innovation Center for Climate Change School of Atmospheric SciencesNanjing UniversityNanjing 210023China

In the context of global warming,the extreme summer precipitation over the Tibetan Plateau(TP)has changed significantly.In this study,the summer(June–August)extreme precipitation on the TP was classified into three spatial types by applying the K-means clustering method to the Third Pole Region long time-series high-resolution(1/30°)precipitation dataset(TPHi Pr,1979–2020).The characteristics of the circulation anomalies and precursors corresponding to the extreme precipitation on the TP in summer during 1979–2020 were investigated.The results showed that the summer extreme precipitation of the TP can be categorized into northwestern(NW),southeastern(SE),and southern Himalayan(HS)types based on extreme precipitation thresholds.The NW and SE types are mainly influenced by anomalous signals in the mid-to-high latitude regions upstream of them,whereas the HS type is controlled by the localized subtropical anomalous circulation.On the 8th day before the onset of the NW type,an anomalous cyclone was observed in the western Atlantic Ocean(60°W,50°N),which triggered the west-to-east quasi-latitudinal propagation of Rossby waves.On the onset day of the NW type,the upper troposphere showed positive-negative-positive geopotential height anomalies along the latitudinal 40°N from the Caspian Sea,the western part of Xinjiang,to the northeastern TP.Moisture entered from the Arabian Sea along the southeastern edge of the anomalous cyclone on the southwestern TP and converged in the northwestern TP.Compared to the NW type,the precursors of the SE type appeared at higher latitudes and were more intense.On the 8th day before the onset of the SE type,an anomalous cyclone occurred near Greenland(60°W,70°N)and excited Rossby waves propagating southeastward.On the onset day of the SE type,the upper troposphere showed negative-positive-negative geopotential height anomalies across Eurasia from the Ural Mountains and the Iranian Plateau to the northern TP in the northwest-southeast direction and entered the southeastern TP from the Bay

关键词： Tibetan Plateau Summer extreme precipitation Atmospheric circulation anomaly Precursor Teleconnection wave train

Analysis of photocatalytic degradation of polyamide microplastics in metal salt solution by high resolution mass spectrometry

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Journal of Environmental Sciences 2024年第5期139卷 473-482页

作者： Yunjin zhong Lebing Zhuo Wangyang Lu National Engineering Lab for Textile Fiber Materials&Processing Technology(Zhejiang) School of Materials Science&EngineeringZhejiang Sci-Tech UniversityHangzhou 310018China

Microplastic pollution has become one of the most concerned focuses in the world.Among many treatment methods,photocatalysis is considered to be one of the most environmentally friendly methods.In this work,the photodegradation behavior of polyamide microplastics is studied by using polyamide 6(PA6)as model microplastics and FeCl_(3) as catalyst.It is hoped that the PA6 fiber can be effectively degraded by utilizing the strong oxidizing active species that can be produced after FeCl_(3) is irradiated in water.The results shows that PA6 fiber can be almost completely degraded after 10 days of irradiation in FeCl_(3) aqueous solution,indicating that it is promising to use this new method to solve the problem of PA6type microplastics.In addition,the chain scission mechanism and degradation process of PA6 are analyzed in detail by ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS),which provides a new insight for the study of polymer degradation mechanism.

关键词： FeCl_(3) Photocatalysis Polyamide 6 Chain scission

Hot versus cold subduction initiation

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National Science Review 2024年第2期11卷 101-102页

作者： zhong-Hai Li Key Laboratory of Computational Geodynamics College of Earth and Planetary SciencesUniversity of Chinese Academy of Sciences

In the framework of plate tectonics, subduction initiation(SI) indicates the birth of a plate convergent boundary, which is a key point of plate tectonics and Wilson's cycle; however, its dynamic process is not well c... 详细信息

关键词： DRIVEN CRUST

Early diagnosis and management of neonatal sepsis:a perspective

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World Journal of Pediatrics 2024年第4期20卷 303-306页

作者： Li‑zhong Du Neonatal Intensive Care Unit Children’s Hospital Zhejiang University School of MedicineNational Clinical Research Center for Child Health3333 Binsheng RoadHangzhou 310052China

Neonatal sepsis is an illness caused by bloodstream bacteria or fungal infections that affect newborn infants under 28 days of age.It stands as a significant contributor to morbidity and mortality in neonatal intensive care units(NICUs).With the improved survival rates of very low-birth-weight or extremely premature infants,a growing number of these vulnerable infants are receiving intensive care and undergoing invasive procedures,making nosocomial infections a persistent challenge in NICUs.The mortality rate associated with neonatal sepsis varies depending on factors such as birth weight,gestational age,and other co-morbidities.It can also lead to a range of long-term health consequences,including neurodevelopmental disabilities like cerebral palsy,visual or hearing impairments,and cognitive problems.Furthermore,neonatal sepsis is linked to various adverse outcomes,including respiratory complications,bronchopulmonary dysplasia,nutritional and growth issues,and immunological dysfunction[1].Due to its atypical clinical presentation and the low rate of specific diagnostic indicators,such as a positive blood culture,accurately diagnosing neonatal sepsis is challenging.Consequently,the appropriateness of antibiotic treatment is often a matter of controversy.

关键词： neonatal mortality diagnosis

Modeling and Simulation of Lithium Vacuum Evaporation Process Using COMSOL Multiphysics

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Journal of Thermal Science 2024年第1期33卷 86-100页

作者： LIAN Xuexin zhong Dawen Beijing Key Laboratory of Passive Nuclear Power Safety and Technology North China Electric Power UniversityBeijing 102206China

Based on the COMSOL Multiphysics simulation software,this study carried out modeling and numerical simulation for the evaporation process of liquid metal lithium in the vacuum free molecular flow state.The motion of lithium atoms in the evaporation process was analyzed through a succession of studies.Based on the available experimental values of the saturated vapor pressure of liquid metal lithium,the relationship between saturated vapor pressure and temperature of liquid lithium in the range of 600 K-900 K was obtained.A two-dimensional symmetric model(3.5 mm×20 mm) was established to simulate the transient evaporation process of liquid lithium at wall temperatures of 750 K,780 K,800 K,810 K,825 K,and 850 K,respectively.The effects of temperature,the evaporation coefficient,back pressure,and length-to-diameter ratio on the evaporation process were studied;the variation trends and reasons of the molecular flux and the pressure during the evaporation process were analyzed.At the same time,the evaporation process under variable wall temperature conditions was simulated.This research made the evaporation process of liquid lithium in vacuum molecular flow clearer,and provided theoretical support for the space reactor and nuclear fusion related fields.

关键词： free molecular flow saturated vapor pressure vacuum evaporation liquid lithium metal

Analysis of gravity wave activity during stratospheric sudden warmings in the northern hemisphere

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Earth and Planetary Physics 2024年第2期8卷 415-422页

作者： XuanYun Zeng Guang zhong School of Physics and Electronic Sciences Changsha University of Science and TechnologyChangsha 410000China Key Laboratory of Geospace Environment Chinese Academy of SciencesUniversity of Science&Technology of ChinaHefei 230026China

Due to the significant changes they bring to high latitude stratospheric temperature and wind,stratospheric sudden warmings(SSWs)can have an impact on the propagation and energy distribution of gravity waves(GWs).The variation characteristics of GWs during SSWs have always been an important issue.Using temperature data from January to March in 2014−2016,provided by the Constellation Observing System for Meteorology,Ionosphere and Climate(COSMIC)mission,we have analyzed global GW activity at 15−40 km in the Northern Hemisphere during SSW events.During the SSWs that we studied,the stratospheric temperature rose in one or two longitudinal regions in the Northern Hemisphere;the areas affected extended to the east of 90°W.During these SSWs,the potential energy density(E_(p)of GWs expanded and covered a larger range of longitude and altitude,exhibiting an eastward and downward extension.The E_(p)usually increased,while partially filtered by the eastward zonal winds.When zonal winds weakened or turned westward,E_(p)began to strengthen.After SSWs,the E_(p)usually decreased.These observations can serve as a reference for analyzing the interaction mechanism between SSWs and GWs in future work.

关键词： stratospheric sudden warming gravity wave wind filter

Tuning Surface Molecular Design of Porous Carbon for Blue Energy Harvesting

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Research 2024年第1期2023卷 651-662页

作者： Jian Yu zhong-Lin Wang Tianwei Ma Department of Civil and Environmental Engineering University of Hawaii at MānoaHonoluluHI 96822USA Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of SciencesBeijing 101400China College of Engineering Texas A&M University-Corpus ChristiCorpus ChristiTX 78412USA

Capacitive mixing is a promising blue energy technology due to its membrane-free electricity generation and long electrode life cycle.However,because of limited performance,existing systems do not lend themselves to practical implementation.Although it is a crucial factor directly influencing electrode behavior,surface chemistry has largely been overlooked in capacitive mixing.Here,we show that manipulating surface functionalization alone can tune the responses of electrodes to produce a high voltage rise without altering the pore structure of the electrodes.Our findings reveal that the spontaneous electrode potential of a surface-modified carbon electrode shifts negatively proportional to the surface charge due to the surface groups,which explains why and how manipulating the surface chemistry can improve the power generation capacity.

关键词： electrode Porous mixing