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A strategy to achieve efficient green-emission dual-mode luminescence of Yb^(3+),Er^(3+) doped NaBiF_(4)

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Rare Metals 2021年第8期40卷 2040-2048页

作者： Jin-Hui xie Jue Wang Gui-Hua Qiu xi-bing li Wen-Tao Huang Rui-Rong Zhang Tong lin li-xi Wang Qi-Tu Zhang College of Materials Science and Engineering Nanjing Tech UniversityNanjing210009China Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites Nanjing210009China Shandong Institute of Non-metallic Material Jinan250031China

A series of hexagonal phase NaBiF_(4):x Yb^(3+),y Er^(3+) were successfully synthesized by solvothermal *** morphology,phase structure,up-conversion luminescence and down-conversion luminescence properties of Yb^(3+) and Er^(3+) doping concentration and the energy transfer mechanism were *** shows that the doping of Yb^(3+) and Er^(3+) does not cause the phase transition of NaBiF_(4),but influences its *** the NaBiF_(4):Yb^(3+),Er^(3+),Yb^(3+) can transfer energy with Er^(3+),enhancing up-conversion green *** Yb^(3+) doping concentration increasing,the up-conversion red-green ratio will increase while the down-conversion intensity of the green emission decreases and that of the red emission *** the potential application of Na BiF4:x Yb^(3+),y Er^(3+) phosphors in optical illumination,the thermal stability was carried out.

关键词： NaBiF_(4) Dual-mode luminescence Energy transfer High temperature fluorescence

Synthesis and luminescence of ultrasmall CsPbBr_(3) nanocrystals and CsPbBr_(3)/Cs_(4)PbBr_(6) composites by one-pot method

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Rare Metals 2022年第4期41卷 1230-1238页

作者： xi-bing li Wen-Tao Huang Rui-Rong Zhang Yue Guo Hui-Jie Yang xiao-Yue He Ming-Xun Yu li-xi Wang Qi-Tu Zhang College of Materials Science and Engineering Nanjing Tech UniversityNanjing 210009China Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites Nanjing 210009China Institute of Non-Metallic Materials Ji'nan 250031China College of 2011 Nanjing Tech UniversityNanjing 210009China

All-inorganic perovskites CsPbX_(3)(X=Cl,Br,I)have attracted worldwide interest due to their excellent lumi-nescent ***,Cs_(4)PbBr_(6) have been studied because they can enhance the luminescent efficiency and stability of CsPbBr_(3).Herein,we introduced a microfluidic method based on room-temperature supersat-urated recrystallization to synthesize blue-emitting CsPbBr_(3)nanocrystals(NCs)and green-emitting CsPbBr_(3)/Cs_(4)PbBr_(6)*** ultrasmall CsPbBr_(3)NCs emitted at a deep blue wavelength of 461 nm with the full width at half maximum(FWHM)of 15 *** electron microscopy(TEM)results demonstrated that ultrasmall CsPbBr_(3)NCs with the average particle size of 3.8 nm were synthesized and the CsPbBr_(3)NCs were crystallized as monoclinic structure.

关键词： composites (3) method

Effects of microwave radiation on dynamic compressive properties of basalt

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Transactions of Nonferrous Metals Society of China 2022年第10期32卷 3388-3403页

作者： Tu-bing YIN Fei-yan JIN Qiang li xi-bing li School of Resources and Safety Engineering Central South UniversityChangsha 410083China

The dynamic mechanical properties of basalt affected by microwave were investigated by performing dynamic compressive tests using the SHPB ***,the thermal damage of the treated basalt was characterized by ultrasonic non-destructive testing and nuclear magnetic resonance *** results show that with the increase of microwave power and exposure time,the P-wave velocity,dynamic compressive strength and elastic modulus decrease continuously,and the dynamic failure mode tends to be a more complex *** increase in microwave power and exposure time can enhance the temperature difference and transfer coefficient among minerals,hence intensifying the rock damage induced by thermal shock.

关键词： microwave radiation nuclear magnetic resonance(NMR) dynamic compressive properties thermal damage

Dynamic compressive strength and failure mechanisms of microwave damaged sandstone subjected to intermediate loading rate

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Transactions of Nonferrous Metals Society of China 2022年第11期32卷 3714-3730页

作者： Pin WANG Tu-bing YIN xi-bing li Heinz KONIETZKY School of Resources and Safety Engineering Central South UniversityChangsha 410083China Geotechnical Institute TU Bergakademie FreibergFreiberg09596Germany

To investigate the influence of microwave heating on the dynamic behavior and failure mechanisms of rock,dynamic compression tests were conducted on microwave-irradiated sandstone specimens using a modified split Hopkinson pressure bar(SHPB)*** results show that microwave radiation can effectively weaken the compressive strength of *** specimens show three different failure modes under impact load:tensile failure,tensile−shear composite failure and compressive−shear *** dynamic Poisson’s ratio,calculated using the measured P-and S-wave velocities,is introduced to describe the deformation characteristics of *** the increase in microwave power and heating time,the Poisson’s ratio declines first and then increases slightly,and the turning point occurs at 244.6℃.Moreover,the microstructural characteristics reveal that microwave radiation produces dehydration,pore expansion,and cracking of the *** damage mechanisms caused by microwave radiation are discussed based on thermal stress and steam pressure inside the rock,which provides a reasonable explanation for the experimental results.

关键词： sandstone microwave radiation thermal cracking dynamic compressive strength failure patterns split Hopkinson pressure bar

Cap rock blast caving of cavity under open pit bench

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Transactions of Nonferrous Metals Society of China 2017年第3期27卷 648-655页

作者： xi-ling liU Ke-bing LUO xi-bing li Qi-yue li Wei-hua WANG Feng-qiang GONG School of Resources and Safety Engineering Central South University Changsha 410083 China Hunan Key Laboratory of Resources Exploitation and Hazard Control for Deep Metal Mines Changsha 410083 China

A laser technique based scanning system was employed to make a comprehensive scanning through borehole forunmapped cavity under open pit bench,then the three-dimensional data will be obtained,and these data were used for theoreticalanalysis and numerical simulation to analyze the stability of cap *** emission techniques were also adopted to carry outlong term real time rupture monitoring in cap ***,a complete safety evaluation system for the cap rock was establishedto ensure safe operation of subsequent blasting *** ideal way of eliminating collapse hazard of such cavity is cap rockcaving through deep-hole blasting,thus,two deep-hole blasting schemes named as vertical deep-hole blasting scheme and one-timeraise driving integrated with deep-hole bench blasting scheme were *** vertical deep-hole blasting scheme has moreexplosive consumption,but the relatively simple blasting net work structure can greatly reduce ***,the one-timeraise driving integrated with deep-hole bench blasting scheme can obviously reduce explosive consumption,but the higher technicalrequirements on drilling,explosive charging and blasting network will increase workloads.

关键词： open pit mining cavity laser 3D detection cap rock stability evaluation one-time raise driving deep-hole blasting

Contributors to tidal duration asymmetry with varied coastline configurations on western shelf of Yellow Sea

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Water Science and Engineering 2024年第1期17卷 1-12页

作者： xi Feng Zheng li Hui Feng Jia-yan Yang Shou-peng xie Wei-bing Feng College of Harbor.Coastal and Offshore Engineering Hohai UniversityNanjing 210098China China Harbour Engineering Co. LtdBeijing 100027China Key Laboratory of Port Waterway and Sedimentation Engineering of the Ministry of CommunicationsNanjing 210029China China South-to-North Water Diversion Corporation limited Beijing 100036China

Coastal management in China is confronted with an urgent choice between natural restoration and maintenance of existing seawalls and reclaimed land for economic development.A key criterion for making this decision is the resilience to coastal flooding,which depends on the ability to predict tidal *** duration asymmetry(TDA)is a key parameter in determination of the arrival and duration of flood *** study selected the western inner shelf of the Yellow Sea(WYS)as the study area and investigated the responses of TDA to different shoreline configurations and relative sea level *** responses of TDA to shoreline reconstruction yielded spatial variability locally and *** the nearshore area,the responses of TDA to the complex ocean environment mainly originated from the combined functions of reflection,bottom friction,and advection,which controlled the energy transfer from M2 or S2 constituents to their overtides or compound *** sensitivity of TDA to coastline typologies was not limited to coastal waters but could stretch over the entire inner *** vulnerability of tidal responses was due to the displacement of the M2 amphidrome of the Kelvin wave on the WYS,which in turn changed tidal energy fluxes over the *** relative sea level rise could intensify the feedback of TDA to seawalls and land reclamation.

关键词： Tidal duration asymmetry Western inner shelf of Yellow Sea Natural restoration Relative sea level rise Tidal amphidrome

Effect of thermal treatment on energy dissipation of granite under cyclic impact loading

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Transactions of Nonferrous Metals Society of China 2019年第2期29卷 385-396页

作者： Rong-hua SHU Tu-bing YIN xi-bing li Zhi-qiang YIN li-zhong TANG School of Resources and Safety Engineering Central South UniversityChangsha 410083China Key Laboratory of Deep Coal Mine Excavation Response and Disaster Prevention and Control Anhui University of Science and TechnologyHuainan 232001China

High temperature treatment causes thermal damage to rocks in deep *** study the thermal effect on the energy dissipation of rocks during the dynamic cyclic loading,cyclic impact loading experiments of heat-treated rocks were carried out using the splitting Hopkinson pressure bar(SHPB)experimental *** correlations among the energy dissipation,energy dissipation rate,impact times,accumulated absorbed energy per volume,failure mode and temperature were *** results show that the reflected energy under the first impact increases and finally exceeds the absorbed energy when the temperature increases;however,the total reflected energy decreases above 200℃.The absorbed energy under the first impact and the total absorbed energy all decrease as the temperature increases,the rates of which decrease *** the same phenomenon appears for the transmitted energy and the rate of the transmitted *** the contrary,the rate of the reflected energy increases with the rising *** the temperature increases,the fewer impact times are needed to destroy the *** addition,the failure modes are different when the rock is treated at different temperatures;that is,when the temperature is high,even though the absorbed energy is low,the sample breaks into powder after several impacts.

关键词： energy dissipation granite cyclic impact compression thermal treatment

Strain-promoted S-arylation and alkenylation of sulfinamides using arynes and cyclic alkynes

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Science China Chemistry 2024年第3期67卷 928-935页

作者： xi Zou Boming Shen Gao-lin li Qian liang Yanhua Ouyang binghe Yang Peiyuan Yu bing Gao State Key Laboratory of Chemo/Bio-Sensing and Chemometrics College of Chemistry and Chemical EngineeringInstitute of Chemical Biology and NanomedicineHunan UniversityChangsha 410082China Department of Chemistry and Shenzhen Grubbs Institute Guangdong Provincial Key Laboratory of CatalysisSouthern University of Science and TechnologyShenzhen 518055China

The conversion of commercially available chiral sulfinamides into pharmaceutically useful chiral sulfoximines via direct SIVfunctionalization is synthetically attractive but challenging due to the competitive reaction of N-functionalization. Herein, we disclose a novel strain-release strategy to access stereospecific and chemoselective SIV-arylation and alkenylation of sulfinamides using arynes and strained cyclic alkynes. This method tolerates an unprecedented chemical diversity of functional groups attached to the nitrogen center(N-R). The origin of the high SIV-selectivity is elucidated by density functional theory calculations, suggesting a stepwise mechanism for the aryne substrates and a concerted mechanism for the cyclic alkynes.

关键词： arylation alkenylation sulfoximines sulfinamides arynes

Unloading responses of pre-flawed rock specimens under different unloading rates

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Transactions of Nonferrous Metals Society of China 2019年第7期29卷 1516-1526页

作者： xi-bing li Zheng-hong CHEN Lei WENG Chong-jin li School of Resources and Safety Engineering Central South UniversityChangsha 410083China School of Civil Engineering Wuhan UniversityWuhan 430072China

Based on the stress redistribution analysis of rock mass during the deep underground excavation, the unloading process of pre-flawed rock material was simulated by distinct element method (DEM). The effects of unloading rate and flaw inclination angle on unloading strengths and cracking properties of pre-flawed rock specimens are numerically revealed. The results indicate that the unloading failure strength of pre-flawed specimen exhibits a power-function increase trend with the increase of unloading period. Moreover, combined with the stress state analysis on the flaws, it is found that the unloading failure strength increases with the increase of flaw inclination angle. The cracking distribution of pre-flawed specimens under the unloading condition closely depends on the flaw inclination angle, and three typical types of flaw coalescence are observed. Furthermore, at a faster unloading rate, the pre-flawed specimen experiences a sharper and quicker unloading failure process, resulting in more splitting cracks in the specimens.

关键词： deep underground excavation stress unloading unloading rate flaw inclination angle distinct element method (DEM)