检索结果-南通市图书馆

Chinese Journal of Chemical Physics 2013年第6期26卷 774-779,I0005页

作者： zheng-bo qin Xia Wu Zi-chao Tang State Key Laboratory of Molecular Reaction Dynamics Dalian Institute of Chemical Physics ChineseAcademy of Sciences Dalian 115023 China

We have developed a compact photoelectron imaging facility, including an anion source with dissociative photoelectron attachment to molecules, a linear time-of-flight mass spec-trometry （TOFMS）, and an orthogonal high-resolution threshold photoelectron velocity map imaging spectrometer （VMI）. Intense and cold cluster anions were prepared in photoelectron- attachment processes upon pulsed UV laser ablation of metal target. Combining this anion source with TOFMS-VMI, the achieved mass resolution is about 200, and the electron ki- netic energy resolution is better than 3%, i.e., 30 meV for 1 eV electrons. More importantly, low-energy photoelectron imaging spectra for CH3S- and S2- at 611.46 nm are obtained. In both cases, the refined electron affinities are determined to be 1.86264-0.0020 eV for CH3S and 1.67444-0.0035 eV for S2, respectively. Preliminary results suggest that the apparatus is a powerful tool for estimating precise electron affinities values from threshold photoelectron imaging spectroscopy.

关键词： Threshold photoelectron imaging Dissociative photoelectron attachment Laser induced photoelectron emission

Experimental and Theoretical Study on p-Chlorofluorobenzene in the S0,S1 and D0 States

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2020年第4期33卷 401-410,I0001页

作者： Jia-nan Fan Ting-ting Cui zheng-bo qin Xian-feng zheng Zhi-feng Cui Anhui Province Key Laboratory of Optoelectric Materials Science and Technology Department of PhysicsAnhui Normal UniversityWuhu 241000China

The geometric structures and vibration frequencies of para-chlorofluorobenzene(p-Cl FPh)in the first excited state of neutral and ground state of cation were investigated by resonanceenhanced multiphoton ionization and slow electron velocity-map *** infrared spectrum of S0 state and absorption spectrum for S1←S0 transition in p-Cl FPh were also *** on the one-color resonant two-photon ionization spectrum and two-color resonant two-photon ionization spectrum,we obtained the adiabatic excited-state energy of p-Cl FPh as 36302±4 cm^-*** the two-color resonant two-photon ionization slow electron velocity-map imagin spectra,the accurate adiabatic ionization potential of p-Cl FPh was extrapolated as 72937±8 cm^-1 via threshold ionization *** addition,FranckCondon simulation was performed to help us confidently ascertain the main vibrational modes in the S1 and D0 ***,the mixing of vibrational modes between S0→S1 and S1→D0 has been analyzed.

关键词： Resonance-enhanced multiphoton ionization Slow electron velocity-map imaging Duschinsky mixing para-Chlorofluorobenzene

Black hole evaporation and its remnants with the generalized uncertainty principle including a linear term

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2024年第2期76卷 125-136页

作者： bo Yu zheng-wen Long College of Physics Guizhou UniversityGuiyang550025China

In recent years,researchers have investigated the evaporation of Schwarzschild black holes using various forms of the generalized uncertainty principle(GUP),metric quantum correction,and noncommutative geometry,***,there are differences between the GUP correction and the other two methods in terms of describing the later stages of black hole ***,some studies argue that the GUP with a negative parameter cannot effectively correct black hole evaporation,while others contend that the positivity or negativity of the GUP parameters should not affect the correction *** the above into consideration,we reconsider black hole evaporation with the generalized uncertainty principle including a linear term(LGUP),and examine the case of negative *** results indicate that the evaporation behavior of both Schwarzschild black holes and Reissner–Nordstr?m black holes,under LGUP correction,is consistent with the results of metric quantum correction and non-commutative ***,the negative parameter LGUP can also effectively correct for black hole evaporation.

关键词： black hole evaporation generalized uncertainty principle negative parameter

Selective N-Methylation of N-Methylaniline with CO_(2) and H_(2) over Cu/In_(2)O_(3) Catalyst

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2024年第3期42卷 276-282页

作者： Huan zheng bo Qian Lin He State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhouGansu730000 China University of Chinese Academy of Sciences Beijing100049 China

N-Methylation of amines with CO_(2) and H2 is a potential approach for CO_(2) utilization because N-methylated amines can be used as solvents and organic intermediates. In_(2)O_(3)-supported Cu (Cu/In_(2)O_(3)) acts as an effective heterogeneous catalyst for N-methylation reaction of N-methylaniline (MA) with CO_(2) and H_(2),showing higher N,N-dimethylaniline (DMA) selectivity than other supported Cu catalysts. On one hand,the dispersion of Cu can be improved by the defective In_(2)O_(3) support. On the other hand,In_(2)O_(3) support is active in the dissociative adsorption of CO_(2) through C—O bond breaking. In addition,the H_(2) dissociation ability of In_(2)O_(3) can also be enhanced by Cu. The combination of Cu and In_(2)O_(3) is effective in the activation of CO_(2),the adsorption of intermediate N-methylformanilide (MFA),the hydrogenation of MFA to DMA and the prohibition of C—N bond cleavage side reactions,thereby enhancing the reaction rate of MA conversion and the selectivity to DMA.

关键词： N-Methylation CO_(2) Cu/In_(2)O_(3) Supported catalysts Heterogeneous catalysis

Resource Allocation in Multi-User Cellular Networks:A Transformer-Based Deep Reinforcement Learning Approach

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Communications 2024年第5期21卷 77-96页

作者： Zhao Di zheng Zhong qin Pengfei qin Hao Song Bin State Key Laboratory of Integrated Services Networks Xidian University710071China China Academy of Space Technology Beijing 100081China

To meet the communication services with diverse requirements,dynamic resource allocation has shown increasing *** this paper,we consider the multi-slot and multi-user resource allocation(MSMU-RA)in a downlink cellular scenario with the aim of maximizing system spectral efficiency while guaranteeing user *** first model the MSMURA problem as a dual-sequence decision-making process,and then solve it by a novel Transformerbased deep reinforcement learning(TDRL)***,the proposed TDRL approach can be achieved based on two aspects:1)To adapt to the dynamic wireless environment,the proximal policy optimization(PPO)algorithm is used to optimize the multi-slot RA strategy.2)To avoid co-channel interference,the Transformer-based PPO algorithm is presented to obtain the optimal multi-user RA scheme by exploring the mapping between user sequence and resource *** results show that:i)the proposed approach outperforms both the traditional and DRL methods in spectral efficiency and user fairness,ii)the proposed algorithm is superior to DRL approaches in terms of convergence speed and generalization performance.

关键词： dynamic resource allocation multi-user cellular network spectrum efficiency user fairness

Plasma spray coating on interconnector toward promoted solid oxide fuel cells and solid oxide electrolysis cells

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2024年第3期18卷 390-398页

作者： Junwen CAO Yun zheng Wenqiang ZHANG bo YU Institute of Nuclear and New Energy Technology(INET) Collaborative Innovation Center of Advanced Nuclear Energy TechnologyTsinghua UniversityBeijing 100084China Department of Chemical Engineering University of WaterlooWaterlooOntario N2L 3G1Canada Institute of New Energy Materials and Engineering School of Materials Science and EngineeringFuzhou UniversityFuzhou 350108China

Interconnector is a critical component to construct solid oxide cells (SOCs) stack. Oxidation of metallic interconnectors and Cr poisoning caused by oxidation are important factors that lead to long-term performance degradation of SOCs. Coating on the interconnector surface is an important approach to inhibit the oxidation and Cr migration of the interconnector. Herein, (La0.75Sr0.25)0.95MnO3–δ (LSM) and Mn1.5Co1.5O4 (MCO) are used to fabricate the coatings of interconnector. Two advanced thermal spray technology, atmospheric plasma spraying (APS) and low-pressure plasma spray (LPPS), are adopted for the coating preparation. The electrochemical performance, rising and cooling cycle stability, and Cr diffusion inhibition performance of the coatings are tested and evaluated. The result indicates that MCO can generate more uniform and denser coatings than LSM. In addition, MCO coatings prepared by LPPS shows the best electrochemical performance, rising and cooling cycle stability, and Cr diffusion inhibition. The initial area specific resistance (ASR) is 0.0027 Ω·cm2 at 800 °C. After 4 cooling cycle tests, the ASR increases to 0.0032 Ω·cm2 but lower than other samples. Meanwhile, the relative intense of Cr at the interface of SUS430 with MCO coatings fabricated by LPPS is lower than that of MCO fabricated by APS after 4 rising and cooling cycle operations, showing more favorable Cr diffusion inhibition performance.

关键词： interconnector coating plasma spray electrochemical performance Cr diffusion inhibition solid oxide cells(SOCs)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

On Depolymerization

CCS Chemistry 2024年第2期6卷 297-312页

作者： bo qin Xi Zhang College of Chemistry and Chemical Engineering Hunan UniversityChangsha 410082 Department of Chemistry Tsinghua UniversityBeijing 100084

Polymers have become an essential part of modern life and the global economy on account of their costeffectiveness and versatile ***,most postconsumer polymer wastes are unrecycled,leading to environmental pollution and resource ***,as an efficient chemical recycling approach,holds great promise in establishing a circular polymer *** this review,we attempt to highlight recent and significant advancements in depolymerization *** key research topics are discussed:(1)depolymerization of commodity polymers to produce reusable monomers and high-value chemicals;(2)depolymerization of intrinsically depolymerizable *** is anticipated that this review will reflect the present status and future trends of this rapidly evolving realm of depolymerization.

关键词： depolymerization chemical recycling sustainable polymers circular polymer economy catalysis dynamic covalent chemistry

Polycrystalline ZSM-5 Aggregates Induced by Seed and Catalytic Performance in Methanol to Hydrocarbon

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

无机材料学报 2024年第8期39卷 945-954,I0010-I0013页

作者： WANG Xuchang JIAO Chuyu JI Zhuo JIAO Qirui qin bo DU Yanze zheng Jiajun LI Ruifeng Key Laboratory of Coal Science and Technology MOE Research Centre of Energy Chemical&Catalytic TechnologyTaiyuan University of TechnologyTaiyuan 030024China SINOPEC Dalian Research Institute of Petroleum and Petrochemicals Co. Ltd.SINOPECDalian 116045China

Synthesis of ZSM-5 zeolite typically utilizes small molecule polyamines or quaternary ammonium salts as organic structure guiding agent(OSDA).By contrast,the OSDA-free hydrothermal synthesis system eliminates the use of organic templates and the subsequent calcination *** not only reduces the cost of synthesis,but also prevents environmental pollution from the combustion of organic templates,representing an eco-friendly *** this,literature suggests that even so-called template-free synthesis systems often involve trace amount of organic substances like *** the present work,a calcined commercial ZSM-5 zeolite was served as seed,with sodium aluminate as aluminum source and silica sol as silicon source,ensuring an entirely template-free synthesis *** ZSM-5 aggregates consisted of rod-like nanocrystals were successfully prepared in the completely OSDA-free *** of the Si/Al ratio in ZSM-5 seed,dosage and crystallization conditions such as crystallization temperature and crystallization time on ZSM-5 synthesis were *** results show that a highly crystallinity ZSM-5 aggregate consisting of primary nano-sized crystals less than 100 nm is produced from a gel precursor with 5.6%(in mass)seed after hydrothermal treatment for 48 ***,the Si/Al ratio in ZSM-5 seed has little effect on the topological structure and pore structure of the synthesized ***,the seeds with a low Si/Al ratio facilitate faster crystallization of zeolite and enhance the acidity,especially the strong acid centers,of the *** catalytic performance of the synthesized polycrystalline ZSM-5 was evaluated during dehydration of methanol and compared with a commercial reference *** results exhibit that as compared with the reference catalyst,the fabricated sample has a longer catalytic lifetime(16 h vs 8 h)attributed to its hierarchical pores derived from the loosely packed primary ***

关键词： ZSM-5 polycrystalline aggregate crystal seed structure guiding agent

The Multiple Roles of Autophagy in Neural Function and Diseases

在线全文

学校读者我要写书评

暂无评论

Neuroscience Bulletin 2024年第3期40卷 363-382页

作者： Yan-Yan Li zheng-Hong qin Rui Sheng Department of Pharmacology and Laboratory of Aging and Nervous Diseases Jiangsu Key laboratory of Neuropsychiatric DiseasesCollege of Pharmaceutical Sciences of Soochow UniversitySuzhou 215123China

Autophagy involves the sequestration and delivery of cytoplasmic materials to lysosomes,where proteins,lipids,and organelles are degraded and *** to the way the cytoplasmic components are engulfed,autophagy can be divided into macroautophagy,microautophagy,and chaperone-mediated ***,many studies have found that autophagy plays an important role in neurological diseases,including Alzheimer's disease,Parkinson's disease,Huntington's disease,neuronal excitotoxicity,and cerebral *** maintains cell homeostasis in the nervous system via degradation of misfolded proteins,elimination of damaged organelles,and regulation of apoptosis and ***-mTOR,Beclin 1,TP53,endoplasmic reticulum stress,and other signal pathways are involved in the regulation of autophagy and can be used as potential therapeutic targets for neurological ***,we discuss the role,functions,and signal pathways of autophagy in neurological diseases,which will shed light on the pathogenic mechanisms of neurological diseases and suggest novel targets for therapies.

关键词： Autophagy Neurodegenerative diseases Cerebral ischemia AMPK mTOR Beclin 1 TP53 Endoplasmic reticulum stress

Collinear Velocity-map Photoelectron Imaging Spectrometer for Cluster Anions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2010年第4期23卷 373-380,I0001页

作者：吴侠秦正波谢华吴小虎丛然唐紫超中国科学院大连化学物理研究所分了反心动力学国家重点实验室大连116023

We describe a collinear velocity-map photoelectron imaging spectrometer, which combines a Wiley-McLaren time-of-flight mass analyzer with a dual-valve laser vaporization source for investigating size-selected cluster and reaction intermediate anions. To generate the reaction anions conveniently, two pulsed valves and a reaction channel are employed instead of premixing carrier gas. The collinear photoelectron imaging spectrometer adopts modified velocity-map electrostatic lens, and provides kinetic energy resolution better than 3%. The performance of the instrument is demonstrated on the photodetachment of Si4^- at 532 and 355 nm, and SiaC^- at 532 nm, respectively. In both cases, photoelectron spectra and anisotropy parameters are obtained from the images. For Si4^-, the spectra show two well- resolved vibrational progressions which correspond to the ground state and the first excited state of the neutral Si4 with peak spacing of 330 and 312 cm^-1, respectively. Preliminary results suggest that the apparatus is a powerful tool for characterizing the electronic structure and photodetachment dynamics of cluster anions.

关键词： Laser vaporization source Photodetachment Cluster