检索结果-南通市图书馆

Bioleaching of vanadium from stone coal vanadium ore by Bacillus mucilaginosus:influencing factors and mechanism

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

international Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1828-1838页

作者： Yingbo Dong Jinyu zan Hai Lin school of Energy and Environmental Engineering University of Science and Technology BeijingBeijing 100083China Beijing Key Laboratory on Resource-oriented Treatment of industrial Pollutants Beijing 100083China

Vanadium and its derivatives are used in various industries,including steel,metallurgy,pharmaceuticals,and aerospace *** China has massive reserves of stone coal resources,these resources have low ***,the effective extraction and recovery of metallic vanadium from stone coal is an important way to realize the efficient resource utilization of stone coal vanadium ***,Bacillus mucilaginosus was selected as the leaching *** vanadium leaching rate reached 35.5%after 20 d of bioleaching under optimal operating *** cumulative vanadium leaching rate in the contact group reached 35.5%,which was higher than that in the noncontact group(9.3%).The metabolites of ***,such as oxalic,tartaric,citric,and malic acids,dominated in bioleaching,accounting for 73.8%of the vanadium leaching ***,during leaching,the presence of stone coal stimulated the expression of carbonic anhydrase in bacterial cells,and enzyme activity increased by 1.335-1.905 *** activity positively promoted the production of metabolite organic acids,and total organic acid content increased by 39.31 mg·L^(-1),resulting in a reduction of 2.51 in the pH of the leaching system with stone *** effect favored the leaching of vanadium from stone *** force microscopy illustrated that bacterial leaching exacerbated corrosion on the surface of stone coal beyond 10 *** study provides a clear and promising strategy for exploring the bioleaching mechanism from the perspective of microbial enzyme activity and metabolites.

关键词： Bacillus mucilaginosus stone coal vanadium ore bioleaching carbonic anhydrase organic acids

Topologically protected entanglement switching around exceptional points

在线全文

学校读者我要写书评

暂无评论

Light(science & Applications) 2024年第8期13卷 1631-1644页

作者： zan Tang Tian Chen Xing Tang Xiangdong Zhang Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements of Ministry of Education Beijing Key Laboratory of Nanophotonics&Ultrafine Optoelectronic SystemsSchool of PhysicsBeijing Institute of Technology100081 BeijingChina

The robust operation of quantum entanglement states is crucial for applications in quantum information,computing,and communications^(1–3).However,it has always been a great challenge to complete such a task because of decoherence and ***,we propose theoretically and demonstrate experimentally an effective scheme to realize robust operation of quantum entanglement states by designing quadruple degeneracy exceptional *** encircling the exceptional points on two overlapping Riemann energy surfaces,we have realized a chiral switch for entangled states with high *** to the topological protection conferred by the Riemann surface structure,this switching of chirality exhibits strong robustness against perturbations in the encircling ***,we have experimentally validated such a scheme on a quantum walk *** work opens up a new way for the application of non-Hermitian physics in the field of quantum information.

关键词： exceptional quantum Riemann

surface wave inversion with unknown number of soil layers based on a hybrid learning procedure of deep learning and genetic algorithm

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2024年第2期23卷 345-358页

作者： zan Zhou Thomas Man-Hoi Lok Wan-Huan Zhou Department of Civil and Environmental Engineering Faculty of Science and TechnologyUniversity of MacaoMacaoChina

surface wave inversion is a key step in the application of surface waves to soil velocity ***,a common practice for the process of inversion is that the number of soil layers is assumed to be known before using heuristic search algorithms to compute the shear wave velocity profile or the number of soil layers is considered as an optimization ***,an improper selection of the number of layers may lead to an incorrect shear wave velocity *** this study,a deep learning and genetic algorithm hybrid learning procedure is proposed to perform the surface wave inversion without the need to assume the number of soil ***,a deep neural network is adapted to learn from a large number of synthetic dispersion curves for inferring the layer ***,the shear-wave velocity profile is determined by a genetic algorithm with the known layer *** applying this procedure to both simulated and real-world cases,the results indicate that the proposed method is reliable and efficient for surface wave inversion.

关键词： surface wave inversion analysis shear-wave velocity profile deep neural network genetic algorithm

Changes in snow cover extent in the Central Taurus Mountains from 1981 to 2021 in relation to temperature, precipitation, and atmospheric teleconnections

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain science 2024年第1期21卷 49-67页

作者： Ecmel ERLAT Fulya aydin-KAnDEMiR Department of Geography Ege UniversityIzmir 35100Türkiye Climate Change and Zero Waste Department Antalya Metropolitan MunicipalityAntalya 07310Türkiye Hydropolitics Association Ankara 06680Türkiye

The snow cover over the Taurus Mountains affects water supply, agriculture, and hydropower generation in the region. in this study, we analyzed the monthly snow Cover Extent(sCE) from november to April in the Central Taurus Mountains(Bolkar, Aladaglar, Tahtali and Binboga Mountains) from 1981 to 2021. Linear trends of snow cover season(november to April) over the last 41 years showed decreases in sCE primarily at lower elevations. The downward trend in sCE was found to be more pronounced and statistically significant for only november and March. sCE in the Central Taurus Mountains has declined about-6.3% per decade for 2500-3000 m in november and about-6.0% per decade for 1000-1500 m and 3000+ m in March over the last 41 years. The loss of sCE has become evident since the 2000s, and the lowest negative anomalies in sCE have been observed in 2014, 2001, and 2007 in the last 41 years, which are consistent with an increase in air temperature and decreased precipitation. sCE was correlated with both mean temperature and precipitation, with temperature having a greater relative importance at all elevated gradients. Results showed that there is a strong linear relationship between sCE and the mean air temperature(r =-0.80) and precipitation(r = 0.44) for all elevated gradients during the snow season. The Arctic Oscillation(AO), the north Atlantic Oscillation(nAO), and the Mediterranean Oscillation(MO) winter indices were used to explain the year-to-year variability in sCE over the Central Taurus Mountains. The results showed that the inter-annual variability observed in the winter sCE on the Central Taurus Mountains was positively correlated with the phases of the winter AO, nAO and MO, especially below 2000 m elevation.

关键词： snow cover extent Atmospheric teleconnection Central Taurus Mountains Air temperature and precipitation Geographic information systems Türkiye

Adaptive Bistable stochastic Resonance Based Weak signal Reception in Additive Laplacian noise

在线全文

学校读者我要写书评

暂无评论

China Communications 2024年第1期21卷 228-241页

作者： Jin Liu zan Li Qiguang Miao Li Yang school of Computer science and Technology Xidian UniversityXi’an 710071China state Key Laboratory of integrated services networks Xidian UniversityXi’an 710071China

Weak signal reception is a very important and challenging problem for communication systems especially in the presence of non-Gaussian noise,and in which case the performance of optimal linear correlated receiver degrades *** at this,a novel uncorrelated reception scheme based on adaptive bistable stochastic resonance(ABsR)for a weak signal in additive Laplacian noise is *** analyzing the key issue that the quantitative cooperative resonance matching relationship between the characteristics of the noisy signal and the nonlinear bistable system,an analytical expression of the bistable system parameters is *** this basis,by means of bistable system parameters self-adaptive adjustment,the counterintuitive stochastic resonance(sR)phenomenon can be easily generated at which the random noise is changed into a benefit to assist signal ***,it is demonstrated that approximately 8dB bit error ratio(BER)performance improvement for the ABsR-based uncorrelated receiver when compared with the traditional uncorrelated receiver at low signal to noise ratio(snR)conditions varying from-30dB to-5dB.

关键词： adaptive bistable stochastic resonance additive Laplacian noise low signal to noise ratio uncorrelated reception scheme weak signal reception

Landau quantization effects on damping Kawahara solitons in electron–positron–ion plasma in rotating ionized medium

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2024年第10期76卷 143-152页

作者： E i El-Awady s Hussain n Akhtar Department of Physics Faculty of Science Port Said University Theoretical Physics Division (TPD) PINSTECH

For the dynamics of three-dimensional electron–positron–ion plasmas, a fluid quantum hydrodynamic model is proposed by considering Landau quantization effects in dense ***–neutral collisions in the presence of the Coriolis force are also considered. The application of the reductive perturbation technique produces a wave evolution equation represented by a damped Korteweg–de Vries equation. This equation, however, is insufficient for describing waves in our system at very low dispersion coefficients. As a result, we considered the highest-order perturbation, which resulted in the damped Kawahara equation. The effects of the magnetic field, Landau quantization, the ratio of positron density to electron density, the ratio of positron density to ion density, and the direction cosine on linear dispersion laws as well as soliton and conoidal solutions of the damped Kawahara equation are explored. The understanding from this research can contribute to the broader field of astrophysics and aid in the interpretation of observational data from white dwarfs.

关键词： Coriolis force Kawahara equation Landau quantization magnetoplasmas quantum plasma solitary and cnoidal waves

Organic Brønsted Acid-Catalyzed stereoselective Cationic RAFT Polymerization:The Effect of RAFT Agents

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 Journal of Polymer science 2024年第6期42卷 711-717页

作者： Zheng-Yi Zhang zan Yang Yun Liao sai-Hu Liao Key Laboratory of Molecule synthesis and Function Discovery(Fujian Province University) College of ChemistryFuzhou UniversityFuzhou350108China state Key Laboratory of Physical Chemistry of solid surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China Beijing national Laboratory for Molecular sciences Beijing100190China

The tacticity of vinyl polymers is a key factor affecting the properties of ***,organic Brønsted acids have been demonstrated as effective catalysts for the development of highly stereoselective cationic reversible addition-fragmentation chain transfer(RAFT)polymerizations of vinyl ethers,in which the use of RAFT agents could allow the control the molecular weight and tacticity of polymer products ***,the effect of RAFT agents on the tacticity-regulation remains elusive and lacks of *** this study,we synthesized four types of RAFT agents and evaluated their influence in the stereoselective cationic polymerization of isobutyl vinyl ether in the presence of PADi as a Brønsted acid catalyst,which unveils that the Z group of RAFT agents could not only affect the polydispersity of the products,but also exert a profound effect on the *** extensive screening of the RAFT agents,high stereoregularity(isotacticity,90%m)was obtained when using dithiocarbonate ester-type RAFT agents with a benzyloxy Z group.

关键词： Bronsted acid catalysis stereoselective cationic polymerization RAFT polymerization Chain transfer agents Tacticity

Counterion-Mediated Hydrogen Bonding Making strong Polyelectrolytes pH-Responsive:Current Understanding and Perspectives

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer science 2024年第9期42卷 1270-1277,I0005页

作者： Yue Huang Guang-Tao Mei zan Hua Guang-Ming Liu Hefei national Research Center for Physical sciences at the Microscale Department of Chemical PhysicsKey Laboratory of Surface and Interface Chemistry and Energy Catalysis of Anhui Higher Education InstitutesUniversity of Science and Technology of ChinaHefei230026China The Key Laboratory of Functional Molecular solids Ministry of Educationand Department of Materials ChemistrySchool of Chemistry and Materials ScienceAnhui Normal UniversityWuhu214002China

The counterion-mediated hydrogen bonding(CMHB)is related to the hydrogen bonding between bound counterions and polyelectrolyte chains in polyelectrolyte systems,where the counterions can both electrostatically bind to the charged groups of polyelectrolyte chains and act as hydrogen bond donors or acceptors to form hydrogen bonds with the hydrogen bond sites associated with polyelectrolyte chains simultaneously.A large number of literatures illustrate that strong polyelectrolytes(sPs)are insensitive to pH,which severely limmits the applications of sPs as smart ***,our studies have demonstrated that the CMHB makes sPs *** perspective discusses the mechanism of pH responsiveness of sPs and the pH-tunable properties of sPs,based on the pH-controlled CMHB *** future research directions on the pH responsiveness of sPs are also discussed *** is anticipated that the study of the pH responsiveness of sPs not only will provide a new understanding of the fundamental properties of sPs,but also will greatly expand the applications of sPs in the field of smart materials.

关键词： Counterion binding Hydrogen bond Polyelectrolyte brush Polyelectrolyte complexation

Phase-field simulation of precipitation kinetics and creep properties of ni-Al-Cr/Ta superalloys

在线全文

学校读者我要写书评

暂无评论

science China(Technological sciences) 2024年第4期67卷 1139-1150页

作者： YAnG shuaiGe ZHAnG zan ZHUO JiCheng LOnG HongLi Li Yongsheng national Key Laboratory of Advanced Casting Technologies MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials TechnologyEngineering Research Center of Materials Behavior and DesignMinistry of EducationNanjing University of Science and TechnologyNanjing 210094China

The precipitation kinetics ofγ'-ni_(3)(Al,Ta)phase and creep properties of ni-15Al-x Ta at.%superalloys are investigated by the crystal plasticity phase-field *** results show that the high Ta content brings a lower creep strain for the deceleration and steady creep stage,while the creep lifetime is *** large external strain intensifies the creep damage and shortens the creep life of ni-15Al-3Ta at.%*** kinetics evolution and elements distribution are revealed in the quaternary ni-10Al-8.5Cr-xT a(x=1.5 at.%,2.0 at.%,2.5 at.%)superalloys by the multi-component phase-field *** anti-phase boundary(APB)changes the coarsening mechanism ofγ'phase,and Ta promotes the precipitation ofγ'phase with an increasing volume fraction and particle *** composition difference betweenγ'andγphases increases with the rising of Ta content,the strong partitioning of Ta toγ'phase strengthens the partitioning of ni and Cr toγmatrix,and Ta shows a superiority than Al in the lattice site occupation of L1_(2)-ni_(3)(Al,X)*** an importantγ'phase forming element,the optimization of Ta content is essential for improving the mechanical properties of ni-based superalloys.

关键词： ni-Al-Ta alloys creep properties kinetics phase-field