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Double [5]carbohelicene: facile synthesis, chiroptical properties,isomerization study, and lasing application

Science China Chemistry 2025年第1期 233-240页

作者： Peipei Liu Yantong Li Meng-Xiang Wu Hao Kang Xiao-Li Zhao Lin xu Linlin Liu Xiaodong Li Junfeng Fang Zhiwei Fang Ya Cheng Hai-Bo Yang Huakang yu xueliang Shi State Key Laboratory of Petroleum Molecular & Process Engineering Shanghai Key Laboratory of Green Chemistry and Chemical ProcessesSchool of Chemistry and Molecular Engineering East China Normal University School of Physics and Optoelectronics South China University of Technology Institute of Polymer Optoelectronic Materials & Devices State Key Laboratory of Luminescent Materials & Devices South China University of Technology School of Physics and Electronic Science Engineering Research Center of Nanophotonics & Advanced Instrument Ministry of EducationEast China Normal University State Key Laboratory of Precision Spectroscopy School of Physics and Electronic Science East China Normal University

Double carbohelicenes have attracted considerable attention due to their aesthetic structures, distinct π-conjugation extension, inherent chirality, and intriguing optical and electronic properties. Herein, the concise de novo synthesis of a new double[5]carbohelicene 1 together with its chiroptical properties, isomerization process and lasing application is presented. 1 was synthesized by a simple protocol involving the formation of a 6,6′-bipentacene as the key intermediate. It is worth noting that1 existed as two diastereomers 1-PP/MM and 1-PM, which were successfully isolated and unambiguously confirmed by Xray crystallography. The optical resolution of the racemic 1-PP/MM was successfully achieved by chiral-phase highperformance liquid chromatography（HPLC）, and 1-PP and 1-MM were characterized by circular dichroism. Interestingly, it was found that 1-PP/MM could be completely isomerized to 1-PM upon heating, and the detailed thermodynamics and kinetics of the isomerization process were systematically investigated. 1-PM exhibited deep-red luminescence with emission maximum at 723 nm and fluorescence quantum yield as high as 32.95%. Consequently, we can showcase the lasing application of 1-PM by doping with epoxy resin to assemble a bottle microlaser spontaneously, which the lasing wavelength is 796.6 nm at a threshold of 0.8 m J cm-2. We believe that our studies, including the facile synthesis methodology, detailed isomerization studies, and lasing application, will shed some light on the design and synthesis of novel carbohelical systems with more functions.

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Simulation study of a dual-cavity window with gravity-driven cooling mechanism

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Building Simulation 2022年第7期15卷 1339-1352页

作者： Liao Li chong Zhang Xinhua xu Jinghua yu Feifei Wang Wenjie Gang Jinbo Wang Department of Building Environment and Energy Engineering Huozhong University of Science&TechnologyWuhanChina Department of Building Services Engineering The Hong Kong Polytechnic UniversityKowloonHong KongChina

Utilization of high temperature cooling sources or natural energy sources can potentially contribute to improving energy efficiency in *** this study,a dual-cavity window with gravity-driven cooling mechanism(GDC window)was proposed to integrate the low-grade cooling sources into the glazing system for improving the thermal performance of the *** embedded pipes circulated with low-grade cooling water are the key component of GDC window,which can remove the absorbed solar heat and reduce the heat gain through the window.A numerical model based on CFD simulation was developed to analyze the flow characteristic and heat transfer within the GDC *** validation was conducted by comparing the simulation results with measurement data obtained from previous *** simulations were carried out to compare the thermal performance of GDC window with that of conventional blinds *** analysis was performed to evaluate the influence of some design parameters on the flow characteristic and thermal performance of GDC *** simulated results show that compared with the blinds window,the GDC window reduces 57.4%and 40.4% of heat gain in summer for the low-grade cooling water of 18℃ and 25℃;*** the flow resistance within the GDC window is significant for improving the heat removal performance of the embedded *** study provides an alternative solution to integrate the low-grade cooling sources into the glazing system for enhancing the energy-efficiency and decreasing the building energy demand in cooling-dominated buildings.

关键词： window system low-grade cooling source active insulation gravity-driven CFD

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Joint Effects and Spatiotemporal Characteristics of the Driving Factors of Landslides in Earthquake Areas

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Journal of Earth Science 2023年第2期34卷 330-338页

作者： Jintao Yang chong xu xu Jin 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 National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China Key Laboratory of Compound and Chained Natural Hazards Dynamics Ministry of Emergency Management of ChinaBeijing 100085China Chengdu yuanjing Technology Co. Ltd.Chengdu 610093China

Understanding the joint effects of earthquakes and driving factors on the spatial distribution of landslides is helpful for targeted disaster prevention and mitigation in earthquake-prone *** far,little work has been done on this *** study analyzed the co-seismic landslide of the Ms8.0 Wenchuan earthquake in 2008 and *** joint effects and spatiotemporal characteristics of the driving factors in seismic regions were *** show that(a)between 2008 and 2014,the dominant driving-factor for landslides has changed from earthquake to rock mass;(b)driving factors with weak driving force have a significant enhancement under the joint effects of other factors;(c)the joint effects of driving factors and earthquake decays with *** study concluded that the strong vibration of the Wenchuan earthquake and the rock mass strength are the biggest contributors to the spatial distribution of landslides in 2008 and 2014,*** means that the driving force of the earthquake is weaker than that of the rock mass after six years of the Wenchuan ***,the landslide spatial distribution can be attributed to the joint effects of the Wenchuan earthquake and driving factors,and the earthquake has an enhanced effect on other factors.

关键词： geodetector co-seismic landslide spatial pattern triggering factors interaction effects driving force engineering geology

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Toward tunable shape memory effect of NiTi alloy by grain size engineering:A phase field study

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Journal of Materials Science & Technology 2024年第1期168卷 276-289页

作者： Bo xu chong Wang Qingyuan Wang Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan ProvinceSichuan UniversityChengdu 610065China Department of Mechanical Science and Engineering College of Architecture and EnvironmentSichuan UniversityChengdu 610065China Key Laboratory of Deep Underground Science and Engineering (Sichuan University)Ministry of EducationChengdu 610065China

The inelastic deformations of shape memory alloys(SMAs)always show poor controllability due to the avalanche-like martensite transformation,and the effective control for the deformation of precision de-vices has been not yet *** this work,the phase field method was used to investigate the shape memory effects(SMEs)of NiTi SMAs undergoing grain size(GS)engineering,to obtain tunable one-way and stress-assisted two-way SMEs(OWSME and SATWSME).The OWSME and SATWSME of the systems with various gradient-nanograin structures and bimodal grain structure,as well as that with geometric gradients were *** simulated results indicate that due to the GS dependences of martensite transformation and reorientation,the occurrence and expansion of martensite reorientation,martensite transformation and its reverse can be efficaciously controlled via the GS *** combining the GS engineering and geometric gradient design,since the effects of GS and stress gradient can be su-perimposed or competing,and the responses of martensite reorientation,martensite transformation and its reverse to this are different,the OWSME and SATWSME of the geometrically graded systems with various nanograin structures can exhibit different improvements in *** short,the reorienta-tion hardening modulus during OWSME is increased and the transformation temperature window during SATWSME is widened by GS engineering,indicating the improved controllability of *** optimal GS engineering schemes revealed in this work provide the basic reference and guidance for designing tun-able SMEs and producing NiTi-based driving devices catering to desired functional performance in various engineering fields.

关键词： Phase field NiTi Shape memory effect Grain size engineering Geometric gradient

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Facile One-Pot Green Synthesis and Antibacterial Activities of GO/Ag Nanocomposites

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Acta Metallurgica Sinica(English Letters) 2017年第1期30卷 36-44页

作者： chong-chong Liu Hui xu Lei Wang xuan Qin College of Chemistry and Materials Science Ludong UniversityYantai 264025China College of Life Sciences Ludong UniversityYantai 264025China School of Materials Science and Engineering Lanzhou University of TechnologyLanzhou 730050China

New materials with good antibacterial activity synthesized by simple, environmentally friendly method have attracted numerous research interests. Taking advantage of Ag and graphene oxide （GO）, the GO/Ag nanocomposites were prepared by a facile, green ＂one-pot＂ reaction to achieve superior antibacterial properties. AgNO3 is as a precursor of Ag nanoparticles （Ag NPs）, and the grape seeds extract as an environmentally friendly reducing and stabilizing agent. The asprepared GO/Ag nanocomposites were characterized by various technologies. The results indicated that the silver ion was reduced by the grade seeds extract and Ag NPs were decorated on the surface of GO nanosheets successfully. The average size of the Ag NPs anchored on the GO surface was 40-50 nm. In this study, we prepared GO/Ag nanocomposites with different Ag NPs to GO ratios and carefully investigated their antibacterial activities. We found that the GO/Ag nanocomposites show better antibacterial activity when the concentration of AgNO3 is 2 mM. GO/Ag nanocomposites have a minimum inhibitory concentration 23.8 μg/mL, lower than bare Ag NPs 25.5 μg/mL. We try to explain the antibacterial mechanism based on optical microscopy observation.

关键词： GO/Ag nanocomposites Green "one-pot" reaction Superior antibacterial properties

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Applicability of Two Newmark Models in the Assessment of Coseismic Landslide Hazard and Estimation of Slope-Failure Probability: An Example of the 2008 Wenchuan M_w 7.9 Earthquake Affected Area

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Journal of Earth Science 2019年第5期30卷 1020-1030页

作者： Siyuan Ma chong xu Key Laboratory of Active Tectonics and Volcano Institute of Geology China Earthquake Administration

This paper presents the landslide hazard assessment and slope-failure function using two Newmark displacement models regressed by regional and global station records. Taking the 2008 Wenchuan M_w 7.9 earthquake area as an example, based on the topographic and geological data of the study area, we prepared a factor-of-safety(Fs) map and a critical acceleration(ac) map, respectively. Then using these two simplified Newmark models, two displacement maps were compiled by combining the ac map and peak ground acceleration(PGA) map. By virtue of the actual landslide inventory of the Wenchuan earthquake, we constructed the slope-failure probability curves of the two Newmark models. The results show that the abilities to predict landslide occurrence of the two simplified Newmark models are largely identical, by which the assessment results can well delineate the macroscopic distribution of coseismic landslides, and most predicted landslide cells are distributed on the two sides of the Beichuan-Yingxiu fault, especially Pengguan complex rock mass in the hanging wall of this fault. The probability equations of two Newmark models are roughly the same, though the parameters vary slightly. The probability equation proposed in this paper can be applied to the Wenchuan region and other areas with similar tectonic environments.

关键词： Wenchuan earthquake seismic landslides Newmark displacement peak ground acceleration(PGA)

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Rational design of lipid-activatable NIR-II probes for precisely imaging atherosclerotic plaque

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Science China Chemistry 2025年

作者： Xinyu xu yuan Ma Hui Cao Li xu Haoming Chen Sulai Liu Wei Sun Guosheng Song Xiaobing Zhang State Key Laboratory for Chemo/Bio-Sensing and Chemometrics College of Chemistry and Chemical EngineeringHunan University Department of Hepatobiliary Surgery/Central Laboratory Hunan Provincial People's Hospital (The First Affiliated Hospital of Hunan Normal University) Department of Cardiology the First Affiliated Hospital of Nanjing Medical University Key Laboratory of Targeted Intervention of Cardiovascular Disease Collaborative Innovation Center for Cardiovascular Disease Translational MedicineNanjing Medical University Shenzhen Research Institute of Hunan University

Atherosclerosis(AS) is a prevalent condition associated with cardiovascular and cerebrovascular diseases, featuring lipid-laden plaque; however, the insufficient resolution and low sensitivity of traditional medical imaging techniques limit their application in lipid imaging. Currently, the second near-infrared(NIR-II) fluorescence imaging offers promising sensitivity and convenience. However, existing probes have limitations in terms of signal-to-background ratio, penetration depth, and tissue scattering. Herein, we use a molecular regulatory strategy to design a lipid-activatable probe Rh-965 with high specificity and NIR-II emission for improved imaging potential in deep tissues. The potential of Rh-965 for imaging plaque lipids in mice with AS is demonstrated by localizing carotid artery plaques using NIR-II imaging. The development of more stable lipid-activated NIR-II probes can significantly enhance atherosclerosis diagnosis and facilitate in vivo imaging in deeper tissues.

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CONSTRUCTION OF GEOMETRIC PARTIAL DIFFERENTIAL EQUATIONS FOR LEVEL SETS

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Journal of Computational Mathematics 2010年第1期28卷 105-121页

作者： chong Chen Guoliang xu LSEC ICMSEC Academy of Mathematics and Systems Science Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences Beijing 100190 China LSEC ICMSEC Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

Geometric partial differential equations of level-set form are usually constructed by a variational method using either Dirac delta function or co-area formula in the energy functional to be minimized. However, the equations derived by these two approaches are not consistent. In this paper, we present a third approach for constructing the level-set form equations. By representing various differential geometry quantities and differential geometry operators in terms of the implicit surface, we are able to reformulate three classes of parametric geometric partial differential equations （second-order, fourth-order and sixth- order） into the level-set forms. The reformulation of the equations is generic and simple, and the resulting equations are consistent with their parametric form counterparts. We further prove that the equations derived using co-area formula are also consistent with the parametric forms. However, these equations are of much complicated forms than these given by the equations we derived.

关键词： Geometric partial differential equations Level set Differential geometry operators.

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High-precision tip positioning composite feedforward control of linear colocated motion systems with Bi-Loop iterative feedforward tuning

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Science China Technological Sciences 2025年

作者： Junyu HU Yourui TAO Shanhu LI xu HAN College of Mechanical and Vehicle Engineering Hunan University State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology

To enhance the tip positioning accuracy and robustness against disturbances of linear colocated motion systems, a novel composite feedforward (COMFF) control with Bi-Loop iterative feedforward tuning (IFFT) is proposed. The tip positioning error consists of the coupled tip residual vibration and linear motor tracking error. Given the influence of nonlinear friction and load flexibility, the topology of COMFF is designed as decoupled structures so that COMFF can suppress the tip residual vibration and compensate for the linear motor tracking error compatibly. Furthermore, Bi-Loop IFFT is built to improve the robustness of COMFF in high-precision motor tracking performance. In the state space of the linear motor tracking error based on the projection theorem, two loops are performed in parallel along the iteration direction. One is the P-type iteration loop that drives linear motor tracking errors to converge to the zero state. The other is the observation loop constructed by the recursive least square with forgetting factors to accelerate the P-type iteration loop. Driven by the P-type iteration loop with the aid of the observation loop, the proposed COMFF is integrated with fast convergence and high robustness when confronted with model disturbances. The effectiveness of the proposed COMFF combined with Bi-Loop IFFT is validated by experiments.

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3D suitability evaluation of urban underground space using a variable weight method and considering ground restrictions

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Underground Space 2024年第6期19卷 208-226页

作者： Jian Pu yu Huang Yandong Bi Zhen Guo Fei Deng Xingyue Li chong xu Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China The State Key Laboratory on Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China Foshan Bureau of Geological Survey of Guangdong Province Foshan 52800China National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China

The evaluation of urban underground space(UUS)suitability involves multiple *** weight to these indicators is crucial for accurate *** paper presents a method for spatially variable weight assignment of indicators using the order relation analysis method(G1-method),the entropy weight method,an improved grey relational analysis(GRA)and a set of spatial weight adjustment ***,the subjective and objective weights of indicators for engineering geological and hydrogeological conditions were determined by the G1-method and entropy weight method,respectively,and their combined weights were then obtained using the principle of minimum discriminatory *** study highlighted the impact of surface restrictions,such as buildings,on UUS,and the degree of the influence of these buildings gradually decreased with the increase in depth of the rock and soil mass in UUS,which resulted in changes in weights of indicators with *** address this issue,a coefficient was defined as the standardized value of the ratio of additional stress applied by restrictions to the self-weight stress of soil at the same depth to modify the combined weights so that all weights of indicators could vary in ***,an improved GRA was used to determine the suitability level of each evaluation cell using the maximum correlation *** method was applied to the 3D suitability evaluation of UUS in Sanlong Bay,Foshan City,Guangdong Province,China,including 16 evaluation *** study comprehensively considered the influence of multiple factors,thereby providing reference for evaluating the suitability of UUS in big cities.

关键词： 3D suitability evaluation Urban underground space Ground restriction Variable weight method Improved grey relational analysis

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