检索结果-南通市图书馆

Structural and Luminescent Properties of Mg_(0.25-x)Al_(2.57)O_(3.79)N_(0.21):xMn^(2+)Green-Emitting Transparent Ceramic Phosphor

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2024年第3期39卷 533-540页

作者：郝留成 MIAO Xiaojun li kai zhong Jianying 涂兵田 YANG Zhangfu 王皓 Pinggao Group Co. LtdPingdingshan 467001China State Key Lab of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Hubei Longzhong Laboratory Xiangyang 430070China School of Materials Science and Engineering Anhui University of Science and TechnologyHuainan 232001China

A series of spinel-type Mg_(0.25-x)Al_(2.57)O_(3.79)N_(0.21):xMn^(2+)(MgAlON:xMn^(2+))phosphors were synthesized by the solid-state reaction *** transparent ceramic phosphors were fabricated by pressureless sintering followed by hot-isostatic pressing(HIP).The crystal structure,luminescence and mechanical properties of the samples were systematically *** transparent ceramic phosphors with tetrahedrally coordinated Mn^(2+)show strong green emission centered around 515 nm under blue light *** the Mn^(2+)concentration increases,the crystal lattice expands slightly,resulting in a variation of crystal field and a slight red-shift of green emission *** weak absorption peaks in the transmittance spectra originate from the spin-forbidden ^(4)T_(1)(^(4)G)→^(6)A_(1) transition of Mn^(2+).The decay time was found to decrease from 5.66 to 5.16 ms with the Mn^(2+)*** present study contributes to the systematic understanding of crystal structure and properties of MgAlON:xMn^(2+)green-emitting transparent ceramic phosphor which has a potential application in high-power light-emitting diodes.

关键词： transparent ceramic phosphor green emission MgAlON photoluminescence

Variation characteristics of acid rain in Zhuzhou,Central China over the period 2011-2020

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第4期138卷 496-505页

作者： Jiahao Ren liquan Zhu Xi Zhang Yuqian Luo Xuecai zhong Bowen li Yuwen Wang kai Zhang State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China Zhuzhou Environment Monitoring Center Zhuzhou 412000China Faculty of Environmental Engineering The University of Kitakyushu1–1 HibikinoWakamatsuKitakyushuFukuoka 808-0135Japan College of Natural Resources and Environment South China Agricultural UniversityGuangzhou 510642China

Zhuzhou was one of the most polluted cities in China with the serious acid *** to the implementation of air pollution control measures from 2016 to 2018,the acid rain pollution in this city has *** order to understand the recent situation,a comprehensive study on the acid rain was carried out from January 2011 to December *** pH values during the study period varied from 3.3 to 7.5,with a volume-weighted mean value of *** predominant acidic components of the precipitation were SO_(4)^(2-)and NO_(3)^(-),accounting for 89.3% of the total *** ratio of non-sea-salt SO_(4)^(2-)to NO_(3)^(-)showed a decreasing trend,revealing that the pollution type of acid rain changed from sulfuric acid type to sulfuric acid and nitric acid compound *** correlation analysis(p<0.05)showed that SO_(4)^(2-)was positively correlated with NH_(4)^(+),Ca^(2+),and Mg^(2+);hence,it predominated in precipitation as(NH_(4))_(2)SO_(4),NH_(4)HSO_(4),CaSO_(4),and MgSO_(4).Significant positive correlation of Ca^(2+)with Mg^(2+)shows that they may originated mainly from *** positive correlation between SO_(4)^(2-)and F^(-)and Cl^(-)indicate that their source may be related to the non-ferrous metal smelting industry in *** correlation analysis shows that emissions from the non-ferrous metal smelting industry in the area have a large significant on SO_(4)^(2-)and F^(-)in precipitation,while Cl^(-)may still be emitted from other anthropogenic sources.

关键词： Acid rain pH Chemical composition Neutralization factor Correlation analysis

Metal-organic framework-derived CoSe_(2)@N-doped carbon nanocubes for high-performance lithium-ion capacitors

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2024年第5期43卷 2150-2160页

作者： Lei Wang Xiong Zhang Yan-Yan Kong Chen li Ya-Bin An Xian-zhong Sun kai Wang Yan-Wei Ma Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China School of Engineering Sciences University of Chinese Academy of SciencesBeijing 100190China Institute of Electrical Engineering and Advanced Electromagnetic Drive Technology Qilu ZhongkeJinan 250013China School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China

Cobalt selenide(CoSe_(2))has garnered considerable attention as a prospective anode candidate for advanced lithium-ion storage,prompting comprehensive ***,CoSe_(2)-based anodes usually suffer from significant volume variation upon lithiation leading to unsatisfactory cycling ***,a versatile synthesis route is proposed for the in-situ fabrication of CoSe2nanoparticles embedded in N-dope carbon skeleton(CoSe_(2)@NC)through annealing treatment and selenization of a metal–organic framework-derived(MOF)*** N-doped carbon derived from the MOF serves not only as an excellent conductive substrate but also as a confined reactor,effectively inhibiting the structural instability and alleviating the inevitable volume change of CoSe_(2).Owing to their unique nanostructure,the as-prepared CoSe_(2)@NC exhibits a high capacity of 745.9mAh·g^(-1)at 0.1 A·g^(-1),while maintaining excellent rate capability and an impressive ***,the assembled lithium-ion capacitor(liC)based on CoSe_(2)@NC demonstrates an energy density of 130Wh·kg^(-1),a power density of 24.6 kW·kg^(-1),and remarkable capacity retention of 90.8%after 8000 *** results highlight the great potential of CoSe_(2)@NC for practical applications.

关键词： lithium capacitors Cobalt selenide Metal-organic frameworks N-doped carbon

Hot versus cold subduction initiation

在线全文

学校读者我要写书评

暂无评论

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

Sequential Propagation of Chaos for Mean-Field BSDE Systems

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2024年第1期45卷 11-40页

作者： Xiaochen li kai DU Shanghai Center for Mathematical Sciences Fudan UniversityShanghai 200433China. Shanghai Artificial Intelligence Laboratory 701 Yunjin RoadShanghai 200433China

A new class of backward particle systems with sequential interaction is proposed to approximate the mean-field backward stochastic differential *** is proven that the weighted empirical measure of this particle system converges to the law of the McKean-Vlasov system as the number of particles *** on the Wasserstein met-ric,quantitative propagation of chaos results are obtained for both linear and quadratic growth ***,numerical experiments are conducted to validate our theoretical results.

关键词： Backward propagation of chaos Particle system Sequential interaction McKean-Vlasov BSDE Convergence rate

Beyond 1,4-addition of in-situ generated(aza-)quinone methides and indole imine methides

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第7期35卷 35-53页

作者： Yan-li li Zhi-Ming li kai-kai Wang Xiao-Long He Medical College Xinxiang UniversityXinxiang 453000China School of Pharmacy Xinxiang UniversityXinxiang 453000China School of Food and Bioengineering Xihua UniversityChengdu 610039China

The conjugate addition of in-situ generated(aza-)quinone methides(QMs)and indole imine methides(IIMs)emerged as a powerful protocol to access densely functionalized benzenes and *** alcohols,aminobenzhydryl alcohols,and varied indolylmethanols served as most effective precursors for the in-situ generation of such reactive species under acid *** relevant propargylic alcohol has proven to be an elegant precursor to generate the propargylic-QMs and-IIMs via the acid promoted dehydration process,thus enabling diverse challenging remote activation to proceed conjugate1,6-and 1,***,the heteroarene has proven to be workable to transfer the LUMO of the p-QMs and 2-IIMs,thus inducing the remote nucleophilic dearomative *** conjugate additions of(aza-)p-QMs and varied IIMs has made significant contribution in the field of remote activation chemistry in past *** review summarizes the latest advances of the remote conjugate additions of the in-situ generated QMs and IIMs.

关键词： Conjugate addition QMs IIMs LUMO Remote activation Dearomative addition

Robustness of the octupole collectivity in 144Ba within the cranking covariant density functional theory in 3D lattice

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第8期35卷 124-131页

作者： Ze‑kai li Yuan‑Yuan Wang Mathematics and Physics Department North China Electric Power UniversityBeijing 102206China Hebei Key Laboratory of Physics and Energy Technology North China Electric Power UniversityBaoding 071000China

The octupole deformation and collectivity in octupole double-magic nucleus 144Ba are investigated using the Cranking covariant density functional theory in a three-dimensional lattice *** reduced B(E3)transition probability is implemented for the first time in semiclassical approximation based on the microscopically calculated electric octupole *** available data,including the I-ωrelation and electric transitional probabilities B(E2)and B(E3)are well ***,it is shown that the ground state of 144Ba exhibits axial octupole and quadrupole deformations that persist up to high spins(I≈24h).

关键词： Octupole collectivity Cranking covariant density functional theory Rotational spectrum Electric transitional probabilities

Impact of the Political Risk on Food Reserve Ratio:Evidence Across Countries

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2024年第5期37卷 2071-2103页

作者： XING kai li Shang YANG Xiaoguang School of Economics&Management Nanchang UniversityNanchang330031China Department of Statistics and Data Science National University of Singapore119077Singapore Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100190China

Using an unbalanced panel data covering 75 countries from 1991 to 2019,the authors explore how the political risk impacts on food reserve *** empirical findings show that an increasing political risk negatively affects food reserve ratio,and the same effects hold for both internal risk and external ***,the authors find that the increasing external or internal risks both negatively affect food production and food exports,but external risk does not significantly impact food imports and it positively impacts food consumption,while internal risk negatively impacts food imports and food *** results suggest that most governments have difficulty raising subsequent food reserve ratios in face of an increasing political risk,no matter if it is an internal risk or an external risk although the mechanisms behind the impacts are different.

关键词： External risk food reserve ratio internal risk political risk

Mechanism of high-energy pulsed current-assisted rolling of 08AL carbon steel ultra-thin strip

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第2期31卷 416-427页

作者： zhong-kai Ren Ya-nan Xu Jia-zhao Chen He li Rui-lin Yuan Zhen-hua Wang Tao Wang Xiao liu College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan030024ShanxiChina Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment(Ministry of Education) Taiyuan University of TechnologyTaiyuan030024ShanxiChina National Key Laboratory of Metal Forming Technology and Heavy Equipment China National Heavy Machinery Research Institute Co.Ltd.Xi’an710016ShaanxiChina

To improve the plastic deformation performance of a 08AL carbon steel ultra-thin strip,a pulsed electric field was integrated into the plastic processing of the ultra-thin strip,and the effects of high-energy current on its deformation ability were ***-assisted tensile tests were employed,and the results clarified that the pulsed current could reduce the activation energy of faults and promoted dislocation slip within grains and at grain boundaries,leading to a decrease in the deformation resistance of the metal and an increase in its plastic *** the current density of 2.0 A/mm2,the yield strength,tensile strength,and elongation of the rolled sample reached 425 MPa,467 MPa,and 12.5%,*** the rolling process,it was found that the pulsed current promoted the dynamic recrystallization of the ultra-thin strip,reduced its dislocation density and deformation resistance,and promoted the coordinated deformation of the metal.

关键词： 08AL ultra-thin strip High-energy pulsed current Mechanical property Dislocation density Dynamic recrystallization