期刊文献+
共找到19,124篇文章
< 1 2 250 >
每页显示 20 50 100
Dialectical Thermodynamics’Solution to the Conceptual Imbroglio That Is the Reversible Path
1
作者 José C. Íñiguez 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2024年第2期775-799,共25页
According to the second law of thermodynamics, as currently understood, any given transit of a system along the reversible path proceeds with a total entropy change equal to zero. The fact that this condition is also ... According to the second law of thermodynamics, as currently understood, any given transit of a system along the reversible path proceeds with a total entropy change equal to zero. The fact that this condition is also the identifier of thermodynamic equilibrium, makes each and every point along the reversible path a state of equilibrium, and the reversible path, as expressed by a noted thermodynamic author, “a dense succession of equilibrium states”. The difficulties with these notions are plural. The fact, for example, that systems need to be forced out of equilibrium via the expenditure of work, would make any spontaneous reversible process a consumer of work, this in opposition to common thermodynamic wisdom that makes spontaneous reversible processes the most efficient transformers of work-producing-potential into actual work. The solution to this and other related impasses is provided by Dialectical Thermodynamics via its previously proved notion assigning a negative entropy change to the energy upgrading process represented by the transformation of heat into work. The said solution is here exemplified with the ideal-gas phase isomerization of butane into isobutane. 展开更多
关键词 thermodynamic Reversibility Solution to Inconsistencies Dialectical thermodynamics
下载PDF
Improving hydrogen storage thermodynamics and kinetics of Ce-Mg-Ni-based alloy by mechanical milling with TiF_(3)
2
作者 Hongwei Shang Wei Zhang +4 位作者 Xin Wei Yaqin Li Zeming Yuan Jun Li Yanghuan Zhang 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第4期1593-1607,共15页
Mg-based hydrides are too stable and the kinetics of hydrogen absorption and desorption is not satisfactory.An efficient way to improve these shortcomings is to employ reactive ball milling to synthesize the nanocompo... Mg-based hydrides are too stable and the kinetics of hydrogen absorption and desorption is not satisfactory.An efficient way to improve these shortcomings is to employ reactive ball milling to synthesize the nanocomposite materials of Mg and additives.In this experiment,TiF_(3)was selected as an additive,and the mechanical milling method was employed to prepare the experimental alloys.The alloys used in this experiment were the as-cast Ce_(5)Mg_(85)Ni_(10),as-milled Ce_(5)Mg_(85)Ni_(10)and Ce_(5)Mg_(85)Ni_(10)+3 wt.%TiF3.The phase transformation,structural evolution,isothermal and non-isothermal hydrogenation and dehydrogenation performances of the alloys were inspected by XRD,SEM,TEM,Sievert apparatus,DSC and TGA.It revealed that nanocrystalline appeared in the as-milled samples.Compared with the as-cast alloy,ball milling made the particle dimension and grain size decrease dramatically and the defect density increase significantly.The addition of TiF_(3)made the surface of ball milling alloy particles markedly coarser and more irregular.Ball milling and adding TiF_(3)distinctly improved the activation and kinetics of the alloys.Moreover,ball milling along with TiF_(3)can decrease the onset dehydrogenation temperature of Mg-based hydrides and slightly ameliorate their thermodynamics. 展开更多
关键词 Mg-based hydrides TiF_(3) Ball milling thermodynamics KINETICS
下载PDF
Thermodynamics in a quantum corrected Reissner-Nordstr?m-AdS black hole and its GUP-corrections
3
作者 宋建君 刘成周 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期345-353,共9页
We calculate the thermodynamic quantities in the quantum corrected Reissner-Nordstr?m-AdS(RN-AdS)black hole,and examine their quantum corrections.By analyzing the mass and heat capacity,we give the critical state and ... We calculate the thermodynamic quantities in the quantum corrected Reissner-Nordstr?m-AdS(RN-AdS)black hole,and examine their quantum corrections.By analyzing the mass and heat capacity,we give the critical state and the remnant state,respectively,and discuss their consistency.Then,we investigate the quantum tunneling from the event horizon of massless scalar particle by using the null geodesic method,and charged massive boson W^(±)and fermions by using the Hamilton-Jacob method.It is shown that the same Hawking temperature can be obtained from these tunneling processes of different particles and methods.Next,by using the generalized uncertainty principle(GUP),we study the quantum corrections to the tunneling and the temperature.Then the logarithmic correction to the black hole entropy is obtained. 展开更多
关键词 black hole thermodynamics quantum corrections quantum tunneling generalized uncertainty principle
下载PDF
Two innovative equivalent statements of the third law of thermodynamics
4
作者 陈晓航 周颖慧 陈金灿 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第6期324-328,共5页
It is found from textbooks and literature that there are three different statements for the third law of thermodynamics,i.e., the Nernst theorem, the unattainability statement of absolute zero temperature, and the hea... It is found from textbooks and literature that there are three different statements for the third law of thermodynamics,i.e., the Nernst theorem, the unattainability statement of absolute zero temperature, and the heat capacity statement. It is pointed out that such three statements correspond to three thermodynamic parameters, which are, respectively, the entropy,temperature, and heat capacity, and can be obtained by extrapolating the experimental results of different parameters at ultralow temperatures to absolute zero. It is expounded that because there is no need for additional assumptions in the derivation of the Nernst equation, the Nernst theorem should be renamed as the Nernst statement. Moreover, it is proved that both the Nernst statement and the heat capacity statement are mutually deducible and equivalent, while the unattainability of absolute zero temperature is only a corollary of the Nernst statement or the heat capacity statement so that it is unsuitably referred to as one statement of the third law of thermodynamics. The conclusion is that the Nernst statement and the heat capacity statement are two equivalent statements of the third law of thermodynamics. 展开更多
关键词 Nernst statement heat capacity statement Nernst theorem absolute zero temperature the third law of thermodynamics
下载PDF
Removal of Organochlorine from Model Oil Using Mg-Modified ZSM-5 Zeolite:Dechlorination Performance,Regeneration,and Thermodynamics 被引量:1
5
作者 Cheng Xingyuan Gu Jie +4 位作者 Huang Bingtian Bing Liancheng Han Dezhi Wang Guangjian Wang Fang 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS CSCD 2023年第2期24-32,共9页
Various metal-modified ZSM-5 zeolite adsorbents prepared by the impregnation method were applied to the removal of organic chlorides from model naphtha.The adsorption performance and regeneration stability were invest... Various metal-modified ZSM-5 zeolite adsorbents prepared by the impregnation method were applied to the removal of organic chlorides from model naphtha.The adsorption performance and regeneration stability were investigated by static adsorption experiments.The morphologies,structural features,and physicochemical properties of the adsorbents were characterized by X-ray diffraction,Brunauer-Emmett-Teller analysis,NH3 temperature-programmed desorption,scanning electron microscopy,transmission electron microscopy,and pyridine adsorption infrared spectroscopy.The Mg/ZSM-5 zeolite adsorbent possessed a relatively high specific surface area and good metal dispersion and exhibited the best dechlorination and regeneration performance.The characterization results revealed that introduction of the metal exerted a significant influence on the acidic properties of the catalyst surface.A decrease in the ratio of Brønsted acidic sites to Lewis acidic sites and an increase in the amount of moderately acidic sites were confirmed to be responsible for the excellent adsorption performance of the Mg-modified ZSM-5 zeolite.Furthermore,the Langmuir adsorption isotherm model was applied to study the adsorption equilibrium and thermodynamics of the Mg/ZSM-5 adsorbent under mild conditions.The results revealed that the removal of 1,2-dichloroethane by the Mg/ZSM-5 adsorbent was endothermic,spontaneous,disordered,and primarily involved physical adsorption. 展开更多
关键词 adsorption dechlorination ZSM-5 zeolite metal modification thermodynamics
下载PDF
Crystallization thermodynamics of 2,4(5)-dinitroimidazole in binary solvents 被引量:1
6
作者 Pengbao Lian Lizhen Chen +3 位作者 Dan He Guangyuan Zhang Zishuai Xu Jianlong Wang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第5期173-182,共10页
2,4(5)-Dinitroimidazole(2,4(5)-DNI)is an important organic intermediate,and itself can also be used for energetic material.In this work,the solubility of 2,4(5)-DNI in(methanol+water,acetonitrile+water,acetone+water)b... 2,4(5)-Dinitroimidazole(2,4(5)-DNI)is an important organic intermediate,and itself can also be used for energetic material.In this work,the solubility of 2,4(5)-DNI in(methanol+water,acetonitrile+water,acetone+water)binary solvents were measured by using a dynamic test method from 278.15 K to 323.15 K under 101.1 k Pa.The Jouyban–Acree model,van't Hoff–Jouyban–Acree model,Apelblat–Jouyb an–Acree model,Ma model,and Sun model were used to correlate the experimental data.The values of relative average deviation(RAD)and root-mean-square deviation(RMSD)were very small,indicating that the error between the experimental value and the correlated value was very small.The thermodynamic parameters such as dissolution enthalpy,dissolution entropy and Gibbs energy were calculated based on solubility data.High-purity of 2,4(5)-DNI was efficiently obtained by using cooling and dilution crystallization method. 展开更多
关键词 2 4(5)-Dinitroimidazole Solid-liquid equilibrium Solubility model Three thermodynamic parameters Cooling and dilution crystallization
下载PDF
Dipper Throated Optimization for Detecting Black-Hole Attacks inMANETs
7
作者 Reem Alkanhel El-Sayed M.El-kenawy +3 位作者 Abdelaziz A.Abdelhamid Abdelhameed Ibrahim Mostafa Abotaleb Doaa Sami Khafaga 《Computers, Materials & Continua》 SCIE EI 2023年第1期1905-1921,共17页
In terms of security and privacy,mobile ad-hoc network(MANET)continues to be in demand for additional debate and development.As more MANET applications become data-oriented,implementing a secure and reliable data tran... In terms of security and privacy,mobile ad-hoc network(MANET)continues to be in demand for additional debate and development.As more MANET applications become data-oriented,implementing a secure and reliable data transfer protocol becomes a major concern in the architecture.However,MANET’s lack of infrastructure,unpredictable topology,and restricted resources,as well as the lack of a previously permitted trust relationship among connected nodes,contribute to the attack detection burden.A novel detection approach is presented in this paper to classify passive and active black-hole attacks.The proposed approach is based on the dipper throated optimization(DTO)algorithm,which presents a plausible path out of multiple paths for statistics transmission to boost MANETs’quality of service.A group of selected packet features will then be weighed by the DTO-based multi-layer perceptron(DTO-MLP),and these features are collected from nodes using the Low Energy Adaptive Clustering Hierarchical(LEACH)clustering technique.MLP is a powerful classifier and the DTO weight optimization method has a significant impact on improving the classification process by strengthening the weights of key features while suppressing the weights ofminor features.This hybridmethod is primarily designed to combat active black-hole assaults.Using the LEACH clustering phase,however,can also detect passive black-hole attacks.The effect of mobility variation on detection error and routing overhead is explored and evaluated using the suggested approach.For diverse mobility situations,the results demonstrate up to 97%detection accuracy and faster execution time.Furthermore,the suggested approach uses an adjustable threshold value to make a correct conclusion regarding whether a node is malicious or benign. 展开更多
关键词 black-hole attack mobile ad-hoc network OPTIMIZATION dipper throated optimization
下载PDF
Confirmation of the First Law of Thermodynamics in Theory and Extended Bernoulli Equation
8
作者 Chengshu Jin 《Journal of Applied Mathematics and Physics》 2023年第2期409-420,共12页
The internal energy change of ideal gas does not depend on the volume and pressure. The internal energy change of real gas has not any relation with the volume and pressure, which had been proved. If the internal ener... The internal energy change of ideal gas does not depend on the volume and pressure. The internal energy change of real gas has not any relation with the volume and pressure, which had been proved. If the internal energy change had not any relation with the volume and pressure, we could confirm the first law of thermodynamics in theory. Simultaneously, the internal energy change is the state function that shall be able to be proved in theory. If the internal energy change depended on the volume and pressure, we could not prove that the internal energy change is the state function and the chemical thermodynamics theory is right. The extended or modified Bernoulli equation can be derived from the energy conservation law, and the internal energy change, heat, and friction are all considered in the derivation procedure. The extended Bernoulli equation could be applied to the flying aircraft and mechanical motion on the gravitational field, for instance, the rocket and airplane and so on. This paper also revises some wrong ideas, viewpoints, or concepts about the thermodynamics theory and Bernoulli equation. 展开更多
关键词 First Law of thermodynamics Chemical thermodynamics Bernoulli Equation Static Pressure Head FRICTION
下载PDF
Thermodynamics of warm axionic Abelian gauge inflation
9
作者 李喜彬 武燕玲 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第11期671-680,共10页
Inflationary spectral index from the Langevin equation is calculated under the frame of warm inflationary scenario with inflaton interacting with U(1) gauge fields through the Chern–Simons coupling ∝ФF_(μv)F^(μv)... Inflationary spectral index from the Langevin equation is calculated under the frame of warm inflationary scenario with inflaton interacting with U(1) gauge fields through the Chern–Simons coupling ∝ФF_(μv)F^(μv). Under the strong dissipative condition, the spectral index is calculated in terms of the ratio of Hubble parameter to temperature H/T. Then relation between H/T and other cosmic parameters is analytically expressed, based on which a spectral index related to the Chern–Simons coupling strength is further obtained. Numerical results show that cosmic temperature T closes to a constant during inflation and decreases after inflation without a reheating process. Meanwhile, the ratio H/T tends to a constant if the gauged coupling constant is less than a threshold. This phenomenon shows that cosmic temperature may be an important physical parameter with a special value and adiabatic approximation still holds. We obtain the estimate H/T ≤ 0.3377 during inflation from Planck data and other constraint conditions. 展开更多
关键词 axion inflation thermodynamics
下载PDF
A Computational Study of Microhydrated N-Acetyl-Phenylalaninylamide (NAPA): Kinetics and Thermodynamics
10
作者 Mohammad Alauddin Mohammad Masud Parvez Mohammad Abdul Matin 《Computational Molecular Bioscience》 2023年第4期63-74,共12页
The formations of [NAPA-A(H<sub>2</sub>O)<sub>n</sub> (n = 1, 2, 3, 4)] complexes have been studied employing DFT/wB97XD/cc-pVTZ computational level to understand the kinetics and thermodynamic... The formations of [NAPA-A(H<sub>2</sub>O)<sub>n</sub> (n = 1, 2, 3, 4)] complexes have been studied employing DFT/wB97XD/cc-pVTZ computational level to understand the kinetics and thermodynamics for the hydration reactions of N-acetyl-phenylalaninylamide (NAPA). Thermodynamic parameters such as reaction energy (E), enthalpy (H), Gibb’s free energy (G), specific heat capacity (C<sub>v</sub>), entropy (S), and change of these parameters (ΔE<sub>r</sub>, ΔH<sub>r</sub>, ΔGr, ΔC<sub>r</sub>, and ΔS<sub>r</sub>) were studied using the explicit solvent model. The predicted values of H, G, C, and S increase with the sequential addition of water in NAPA-A due to the increase in the total number of vibrational modes. On the other hand, the value of ΔE<sub>r</sub>, ΔH<sub>r</sub>, and ΔG<sub>r</sub> increases (more negative to less negative) gradually for n = 1, 2, 3, and 4 that indicates an increase of hydration in NAPA-A makes exothermic to endothermic reactions. The barrier heights for the transition states (TS) of [NAPA-A(H<sub>2</sub>O)<sub>n</sub> (n = 1, 2, 3, 4)] complexes are predicted to lie at 4.41, 4.05, 3.72 and 2.26 kcal/mol respectively below the reactants. According to the calculations, the formations of [NAPA-A(H<sub>2</sub>O)<sub>1</sub>] and [NAPA-A(H<sub>2</sub>O)<sub>2</sub>] complexes are barrierless reactions because both water molecules are strongly bonded via two hydrogen bonds in the backbone of NAPA-A. On the contrary, the reactions of [NAPA-A(H<sub>2</sub>O)<sub>3</sub>] and [NAPA-A(H<sub>2</sub>O)<sub>4</sub>] complexation are endothermic and the barrier heights are predicted to stay at 6.30 and 10.54 kcal/mol respectively above the reactants. The free energy of activation (Δ<sup>‡</sup>G<sup>0</sup>) for the reaction of [NAPA-A(H<sub>2</sub>O)<sub>1</sub>], [NAPA-A(H<sub>2</sub>O)<sub>2</sub>], [NAPA-A(H<sub>2</sub>O)<sub>3</sub>], and [NAPA-A(H<sub>2</sub>O)<sub>4</sub>] complexation are 4.43, 4.28, 3.83 and 5.11 kcal/mol respectively which are very low. As well as the rates of reactions are 3.490 × 10<sup>9</sup> s<sup>-1</sup>, 4.514 × 10<sup>9</sup> s<sup>-1</sup>, 9.688 × 10<sup>9</sup> s<sup>-1</sup>, and 1.108 × 10<sup>9</sup> s<sup>-1</sup> respectively which are very fast and spontaneous. 展开更多
关键词 Microhydration DFT Transition States KINETICS thermodynamics
下载PDF
Black Holes and the Third Law of Thermodynamics Revisited
11
作者 Miguel Socolovsky 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2023年第2期499-505,共7页
Black holes contradict the Nernst-Planck (N/P) version of the 3rd law of thermodynamics, but agree with its unattainability (U) version. This happens without contradiction, because the N/P and U versions are not equiv... Black holes contradict the Nernst-Planck (N/P) version of the 3rd law of thermodynamics, but agree with its unattainability (U) version. This happens without contradiction, because the N/P and U versions are not equivalent, namely, N/P implies U but U does not imply N/P. So, black holes obey the weaker version of the 3rd law, but not the stronger one. 展开更多
关键词 thermodynamics Third Law Black Holes
下载PDF
Shadow thermodynamics of AdS black hole with the nonlinear electrodynamics term
12
作者 郑何斌 牟平辉 +1 位作者 陈芸仙 李国平 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第8期201-208,共8页
We creatively employ the shadow radius to study the thermodynamics of a charged Ad S black hole with a nonlinear electrodynamics(NLED)term.First,the connection between the shadow radius and event horizon is constructe... We creatively employ the shadow radius to study the thermodynamics of a charged Ad S black hole with a nonlinear electrodynamics(NLED)term.First,the connection between the shadow radius and event horizon is constructed with the aid of the geodesic analysis.It turns out that the black hole shadow radius shows a positive correlation as a function of the event horizon radius.Then in the shadow context,we find that the black hole temperature and heat capacity can be presented by the shadow radius.Further analysis shows that the shadow radius can work similarly to the event horizon in revealing black hole phase transition process.In this sense,we construct the thermal profile of the charged Ad S black hole with inclusion of the NLED effect.In the P<Pc case,it is found that the N-type trend of the temperature given by the shadow radius is always consistent with that obtained by using the event horizon.Thus,we can conclude for the charged Ad S black hole that the phase transition process can be intuitively presented as the thermal profile in the shadow context.Finally,the effects of NLED are carefully analyzed. 展开更多
关键词 AdS black hole the nonlinear electrodynamics shadow thermodynamics
下载PDF
A Review of Recent Trends in Quantum Thermodynamics and a System’s Behavioural Analysis of the Universe Originating as a Quantum Energy System
13
作者 Stephen J. Palmer 《Journal of Modern Physics》 CAS 2023年第1期60-71,共12页
This paper combines a review of recent advances in quantum thermodynamics, including work on objective collapse (Zurek’s quantum Darwinism) and quantum gravity (Verlinde’s quantum gravity explanation), with a redefi... This paper combines a review of recent advances in quantum thermodynamics, including work on objective collapse (Zurek’s quantum Darwinism) and quantum gravity (Verlinde’s quantum gravity explanation), with a redefinition of entropy generation as systems’ change process. These concepts are used as systems’ behaviour analysis tools to allow us to revisit Hartle and Hawking’s 1983 quantum universe and develop a hypothesis for how physically a universe starting in a quantum state could evolve into our current universe, based on systems analysis. The outcome of this analysis raises a question: do we already have the elements of a “theory of everything” hiding in plain sight within recent advances in quantum thermodynamics? 展开更多
关键词 Exergy Entropy Quantum thermodynamics Systems Behavioural Analysis Quantum Universe
下载PDF
Pseudo-rapidity distributions of charged particles in asymmetric collisions using Tsallis thermodynamics
14
作者 Jun‑Qi Tao Hong‑Bin He +4 位作者 Hua Zheng Wen‑Chao Zhang Xing‑Quan Liu Li‑Lin Zhu Aldo Bonasera 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第11期120-127,共8页
The pseudo-rapidity distributions of the charged particles produced in the asymmetric collision systems p+Al,p+Au and ^(3)He+Au at√S_(NN)=200 GeV GeV are evaluated in the framework of a fireball model with Tsallis th... The pseudo-rapidity distributions of the charged particles produced in the asymmetric collision systems p+Al,p+Au and ^(3)He+Au at√S_(NN)=200 GeV GeV are evaluated in the framework of a fireball model with Tsallis thermodynamics.The fireball model assumes that the experimentally measured particles are produced by fireballs following the Tsallis distribution and it can effectively describe the experimental data.Our results as well as previous results for d+Au collisions at√S_(NN)=200 GeV GeV and p+Pb collisions at√S_(NN)=5.02 TeV TeV validate that the fireball model based on Tsallis thermodynamics can provide a universal framework for pseudo-rapidity distribution of the charged particles produced in asymmetric collision systems.We predict the centrality dependence of the total charged particle multiplicity in the p+Al,p+Au and 3He+Au collisions.Additionally,the dependences of the fireball model parameters(y_(0a),y_(0A),σ_(a) and σ_(A))on the centrality and system size are studied. 展开更多
关键词 Tsallis thermodynamics Fireball model Pseudo-rapidity distribution Heavy-ion collisions Charged particles
下载PDF
Quantum Gravity Based on Generalized Thermodynamics
15
作者 Sergei Yurievich Eremenko 《Journal of Applied Mathematics and Physics》 2023年第4期988-1028,共41页
This paper proposes a novel approach and simplified model of Quantum Gravity based on the unification framework of Generalized Thermodynamics which suggests cross-related terms and modified equations of General Relati... This paper proposes a novel approach and simplified model of Quantum Gravity based on the unification framework of Generalized Thermodynamics which suggests cross-related terms and modified equations of General Relativity and Quantum Mechanics. To address the “background problem”, a metric tensor is introduced into stationary Schrödinger equations via curved coordinates yielding quantum spacetime variation term. Then quantum Lagrangian is added to Einstein-Hilbert functional yielding quantum stress-energy tensor. Obtained from one variational principle, two theories are linked by a common quantum spacetime field. The theory offers some interpretations of the quantum vacuum spacetime fluctuations, zero-point-fields, quantum fields shifting towards high spacetime densities, the quantum nature of spacetime, and black hole singularity. 展开更多
关键词 Quantum Gravity General Relativity Quantum Spacetime Generalized thermodynamics Unified Theory
下载PDF
Thermodynamics and Microphysical Characteristics of an Extreme Rainfall Event Under the Influence of a Low-level Jet over the South China Coast
16
作者 徐碧裕 黎慧琦 +7 位作者 叶朗明 刘显通 饶晓娜 肖辉 徐加民 林青 蒲义良 黄青兰 《Journal of Tropical Meteorology》 SCIE 2023年第2期216-235,共20页
In this paper,the data of Automatic Weather Stations(AWSs),ERA5 reanalysis,sounding,wind profile radar,and dual-polarization radar are used to study an extreme rainfall event in the south China Coast on 11 to 12 May 2... In this paper,the data of Automatic Weather Stations(AWSs),ERA5 reanalysis,sounding,wind profile radar,and dual-polarization radar are used to study an extreme rainfall event in the south China Coast on 11 to 12 May 2022 from the aspects of thermodynamics and microphysical characteristics under the influence of low-level jets(LLJs).Results show that:(1)The extreme rainfall event can be divided into two stages:the first stage(S1)from 0000 to 0600 LST on May 12 and the second stage(S2)from 0700 to 1700 LST on the same day.During S1,the rainfall is mainly caused by the upper-level shortwave trough and the boundary layer jet(BLJ),characterized by strong upward motion on the windward side of mountains.In S2,the combined influence of the BLJ and synoptic-system-related low-level jet(SLLJ)increases the vertical wind shear and vertical vorticity,strengthening the rainstorm.In combination with the effect of topography,a warm and humid southwest flow continuously transports water vapor to farther north,resulting in a significant increase in rainfall over the study area(on the terrain’s windward slope).From S1 to S2,the altitude of a divergence center in the upper air decreases obviously.(2)The rainfalls in the two stages are both associated with the mesoscale convergence line(MCL)on the surface,and the wind field from the mesoscale outflow boundary(MOB)in S1 is in the same direction as the environmental winds.Due to a small area of convergence that is left behind the MOB,convection moves eastward quickly and causes a short duration of heavy rainfall.In S2,the convergence along the MOB is enhanced,which strengthens the rainfall and leads to strong outflows,further enhancing the surface convergence near the MOB and forming a positive feedback mechanism.It results in a slow motion of convection and a long duration of heavy rainfall.(3)In terms of microphysics,the center of a strong echo in S1 is higher than in S2.The warm-rain process of the oceanic type characterizes both stages,but the convective intensity in S2 is significantly stronger than that in S1,featuring bigger drop sizes and lower concentrations.It is mainly due to the strengthening of LLJs,which makes small cloud droplets lift to melting levels,enhancing the ice phase process(riming process),producing large amounts of graupel particles and enhancing the melting and collision processes as they fall,resulting in the increase of liquid water content(LWC)and the formation of large raindrops near the surface. 展开更多
关键词 low-level jet thermodynamics MICROPHYSICS heavy rain south China coast
下载PDF
Li^(+)-ion bound crown ether functionalization enables dual promotion of dynamics and thermodynamics for ambient ammonia synthesis
17
作者 Qiyang Cheng Sisi Liu +8 位作者 Mengfan Wang Lifang Zhang Yanzheng He Jiajie Ni Jingru Zhang Chengwei Deng Yi Sun Tao Qian Chenglin Yan 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第10期191-197,I0007,共8页
Electrosynthesis of ammonia from the reduction of nitrogen is still confronted with the limited supply of gas reactant in dynamics as well as high activation barrier in thermodynamics.Unfortunately,despite tremendous ... Electrosynthesis of ammonia from the reduction of nitrogen is still confronted with the limited supply of gas reactant in dynamics as well as high activation barrier in thermodynamics.Unfortunately,despite tremendous efforts devoted to electrocatalysts themselves,they still fail to tackle the above two challenges simultaneously.Herein,we employ a heterogeneous catalyst adlayer-composed of crown ethers associated with Li^(+)ions-to achieve the dual promotion of dynamics and thermodynamics for ambient ammonia synthesis.Dynamically,the bound Li^(+)ions interact with the strong quadrupole moment of nitrogen,and trigger considerable reactant flux toward the catalyst.Thermodynamically,Li^(+)associated with the oxygen of crown ether achieves a higher density of states at the Fermi level for the catalyst,enabling effortless electron transfer from the catalysts to nitrogen and thus greatly reducing the activation barrier.As expected,the proof-of-concept system achieves an ammonia yield rate of 168.5μg h^(-1)mg^(-1)and a Faradaic efficiency of 75.3%at-0.3 V vs.RHE.This system-level approach opens up pathways for tackling the two key challenges that have limited the field of ammonia synthesis. 展开更多
关键词 Li^(+)-ion bound crown ether DYNAMICS thermodynamics Nitrogen reduction Ammonia synthesis
下载PDF
View of thermodynamic phase transition of the charged Gauss-Bonnet AdS black hole via the shadow
18
作者 何柯腱 郭森 +1 位作者 罗智 李国平 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期355-362,共8页
We examine thermodynamic phase transition(PT)of the charged Gauss-Bonnet Ad S black hole(BH)by utilizing the shadow radius.In this system,we rescale the corresponding Gauss-Bonnet coefficientαby a factor of 1/(D-4),a... We examine thermodynamic phase transition(PT)of the charged Gauss-Bonnet Ad S black hole(BH)by utilizing the shadow radius.In this system,we rescale the corresponding Gauss-Bonnet coefficientαby a factor of 1/(D-4),and ensure thatαis positive to avoid any singularity problems.The equation derived for the shadow radius indicates that it increases as the event horizon radius increases,making it an independent variable for determining BH temperature.By investigating the PT curve in relation to shadows,we can observe that the shadow radius can be used as an alternative to the event horizon radius in explaining the phenomenon of BH PT.Furthermore,the results indicate that an increase in the parameterαcorresponds to a decrease in the temperature of the BH.By utilizing the relationship between the temperature and the shadow radius,it is possible to obtain the thermal profile of the Gauss-Bonnet AdS BH.It is evident that there is an N-type variation in temperature for pressures P<P_(c).Additionally,as the parameterαincreases,the region covered by shadow expands while the temperature decreases.The utilization of BH shadows as a probe holds immense significance in gaining a deeper understanding of BH thermodynamic behavior. 展开更多
关键词 Gauss-Bonnet AdS black hole thermodynamic SHADOW
下载PDF
TP-PROFILE: Monitoring the Thermodynamic Structure of the Troposphere over the Third Pole
19
作者 Xuelong CHEN Yajing LIU +6 位作者 Yaoming MA Weiqiang MA Xiangde XU Xinghong CHENG Luhan LI Xin XU Binbin WANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第6期1264-1277,共14页
Ground-based microwave radiometers(MWRs)operating in the K-and V-bands(20–60 GHz)can help us obtain temperature and humidity profiles in the troposphere.Aside from some soundings from local meteorological observatori... Ground-based microwave radiometers(MWRs)operating in the K-and V-bands(20–60 GHz)can help us obtain temperature and humidity profiles in the troposphere.Aside from some soundings from local meteorological observatories,the tropospheric atmosphere over the Tibetan Plateau(TP)has never been continuously observed.As part of the Chinese Second Tibetan Plateau Scientific Expedition and Research Program(STEP),the Tibetan Plateau Atmospheric Profile(TPPROFILE)project aims to construct a comprehensive MWR troposphere observation network to study the synoptic processes and environmental changes on the TP.This initiative has collected three years of data from the MWR network.This paper introduces the data information,the data quality,and data downloading.Some applications of the data obtained from these MWRs were also demonstrated.Our comparisons of MWR against the nearest radiosonde observation demonstrate that the TP-PROFILE MWR system is adequate for monitoring the thermal and moisture variability of the troposphere over the TP.The continuous temperature and moisture profiles derived from the MWR data provide a unique perspective on the evolution of the thermodynamic structure associated with the heating of the TP.The TP-PROFILE project reveals that the low-temporal resolution instruments are prone to large uncertainties in their vapor estimation in the mountain valleys on the TP. 展开更多
关键词 microwave radiometer thermodynamic structure vertical profile Tibetan Plateau
下载PDF
Thermodynamic model for deoxidation of liquid steel considering strong metal-oxygen interaction in the quasichemical model framework
20
作者 Yong-Min Cho Youn-Bae Kang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第5期988-1002,共15页
Herein,a thermodynamic model aimed at describing deoxidation equilibria in liquid steel was developed.The model provides explicit forms of the activity coefficient of solutes in liquid steel,eliminating the need for t... Herein,a thermodynamic model aimed at describing deoxidation equilibria in liquid steel was developed.The model provides explicit forms of the activity coefficient of solutes in liquid steel,eliminating the need for the minimization of internal Gibbs energy preliminarily when solving deoxidation equilibria.The elimination of internal Gibbs energy minimization is particularly advantageous during the coupling of deoxidation equilibrium calculations with computationally intensive approaches,such as computational fluid dynamics.The model enables efficient calculations through direct embedment of the explicit forms of activity coefficient in the computing code.The proposed thermodynamic model was developed using a quasichemical approach with two key approximations:random mixing of metallic elements(Fe and oxidizing metal) and strong nonrandom pairing of metal and oxygen as nearest neighbors.Through these approximations,the quasichemical approach yielded the activity coefficients of solutes as explicit functions of composition and temperature without requiring the minimization of internal Gibbs energy or the coupling of separate programs.The model was successfully applied in the calculation of deoxidation equilibria of various elements(Al,B,C,Ca,Ce,Cr,La,Mg,Mn,Nb,Si,Ti,V,and Zr).The limitations of the model arising from these assumptions were also discussed. 展开更多
关键词 deoxidation equilibria thermodynamics quasichemical approach computational fluid dynamics
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部