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Estimation of enthalpy of formation Using Benson’s Group Addition and Functional Group Correction

Chemical Research in Chinese Universities 2023年第2期39卷 296-304页

作者： LI Xianlan LUAN Yue LU Yanhua LI Wei MA Lihong ZHANG Qingyou PANG Aimin Henan Engineering Research Center of Industrial Circulating Water Treatment Henan Joint International Research Laboratory of Environmental Pollution Control MaterialsHenan UniversityKaifeng475004P.R.China Science and Technology on Aerospace Chemical Power Laboratory Hubei Institute of Aerospace ChemotechnologyXiangyang441003P.R.China Laboratory&Equipment Managements Service Dalian University of TechnologyDalian116024P.R.China

The enthalpies of formation of solid organic compounds containing carbon,nitrogen,oxygen,and hydrogen were estimated using two suggested descriptor sets,separately,by machine learning methods.The two descriptor sets are both composed of descriptors of Benson’s groups and corrected groups.The main differences between them are that one is generated based on atoms and the other is based on bonds.An in-house program was specially written in Java to extract all the descriptors with a function to ensure that each atom(or bond)of a molecule is represented by Benson’s groups once for an atom-based(or bond-based)descriptor set.Multiple linear regression and partial least squares were used,separately,to build models to predict the enthalpy of formation for two descriptor sets.The combination of the models constructed by two descriptor sets based on the atoms and the bonds achieved the best-predicted results in this paper,and the corresponding results of the test set are better than that in the literature,from which the original data were retrieved.Further,a small data set of fluorinated molecules was collected,and satisfactory results were also obtained for these molecules containing fluorine with the assistance of the former data set.

关键词： enthalpy of formation Group contribution method Benson’s group Multiple linear regression Partial least square

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enthalpy of formation of quasicrystalline phase and ternary solid solutions in the Al-Fe-Cu system

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Rare Metals 2006年第5期25卷 608-613页

作者： I.A.Tomilin S.D.Kaloshkin V.V.Tcherdyntsev Moscow State Institute of Steel and Alloys (Technologycal University) 119049 Leninsky prosp.4MoscowRussia

Standard enthalpies of formation of quasicrystalline phase and the ternary solid solutions in the Al-Fe-Cu system and the intermetaUic compound FeAI were determined by the means of solution calorimetry. The quasicrystalline phase was prepared using two different methods. The first method （I） consisted of ball milling the mixture of powders of pure aluminum copper and iron in a planetary mill with subsequent compacting by hot pressing and annealing. The second method （Ⅱ） consisted of arc melting of the components in argon atmosphere followed by annealing. The latter method was used for preparing the compound FeAl and the solid solutions. The phases were identified using the XRD method. The enthalpy of the formation was determined for the quasicrystalline phase of the composition Al62Cu25.5Fe12.5 and the temary BCC solid solutions Al35Cu14Fe51, Al40Cu17Fe43, and Al50.4Cu19.6Fe30. The measured enthalpy of formation of the intermetallic compound FeAl is in good agreement with the earlier published data. The enthalpies of formation of the quasicrystalline phases prepared using two different methods are close to each other, namely, -22.7±3.4 （method I） and -21.3±2.1 （method Ⅱ） kJ/mol.

关键词： enthalpy of formation calorimetry quasicrystals Al-Fe-Cu

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3,6-bis(2,2,2-trinitroethylnitramino)-1,2,4,5-tetrazine.Structure and energy abilities as a component of solid composite propellants

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Defence Technology（防务技术） 2022年第7期18卷 1148-1155页

作者： Anatoly G.Korepin Natalia M.Glushakova David B.Lempert Anatoly I.Kazakov Gennady V.Shilov Denis V.Korchagin Vadim M.Volokhov Elena S.Amosova Sergey M.Aldoshin Institute of Problems of Chemical Physics Ac.Semenov Avenue 1Chernogolovka142432Russian Federation

The work addresses to the study of the molecular and crystal structure and properties of a new energyintensive compound 3,6-bis(2,2,2-trinitroethylnitramino)-1,2,4,5-tetrazine(NBTAT),first obtained by the authors in 2020.NBTAT compound crystallizes in the monoclinic system,space group P2(1)/n,density at room temperature 1.939 g/cm^(3).The energies of crystal packing and pairwise intermolecular interactions in NBTAT and its unnitrated analogue BTAT were calculated,and their comparative analysis was carried out.The enthalpy of formation of NBTAT molecules was calculated by quantum-chemical methods using Gaussian 09,and the enthalpy of formation of NBTAT in the solid phase(618 kJ/mol)was estimated.The energy capabilities of NBTAT as an oxidizer of solid composite propellants are estimated.It is shown that in metal-free compositions NBTAT is significantly superior to ammonium perchlorate(AP),dinitramide ammonium salt(ADN),HMX,BTAT at all stages of rocket systems,and is comparable to the superdense CL-20 yielding to the latter at the lower stages and slightly winning at the upper stages.

关键词： Nitrogen heterocycles Quantum chemistry enthalpy of formation 3,6-bis(2,2,2-trinitroethylnitramino)-1,2,4,5-tetrazine Crystal structure Energetic ability

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Ab initio energetic study of oxide ceramics with rare-earth elements

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Rare Metals 2006年第5期25卷 549-555页

作者： Matvei Zinkevich Fritz Aldinger Max-Planck-Institut für Metallforschung Institut für Nichtmetallische Anorganische MaterialienUniversitt StuttgartHeisenbergstrasse 3D-70569 StuttgartGermany

Ab initio energetic calculations based on the density functional theory （DFF） and the projector augmented wave method （PAW） for determining the polymorphisms of lanthanide sesquioxides Ln2O3 （where Ln = rare-earth element, Y, and Sc）, LnMO3 perovskites （where M = AI and Ga）, and Ln2B207 pyrochlores （where B = Ti, Zr, and Hf） were reported. The relative lattice stabilities agreed well with the critically assessed results or the experimental results except the C-type Ln2O3 with a cubic structure, for which the calculated total energies were considerably more negative. With the increase of the Ln^3＋-cation radius, the polymorphic structures showed a degenerative tendency. The tendencies and quantities of the enthalpies of formation of the ternary oxide ceramics synthesized from their constituent binary oxides reasonably agreed with the available experimental results, and valuable thermodynamic properties were afforded to the compound, for which no experimental data is available. The enthalpies of formation of both perovskites and pyrochlores tend to become more negative with the increase of the Ln^3＋-cation radius.

关键词： rare earth oxide ceramics ab initio calculation lattice stability enthalpy of formation

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Thermodynamic investigation of phase equilibria in Al–Si–V system

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Journal of Materials Science & Technology 2018年第9期34卷 1592-1601页

作者： Qun Luo Kang Li Qian Li State Key Laboratory of Advanced Special Steel & Shanghai Key Laboratory of Advanced Ferrometallurgy & School of Materials Science and Engineering Shanghai UniversityShanghai 200072 China Materials Genome Institute Shanghai UniversityShanghai 200444 China Shanghai Institute of Materials Genome Shanghai 200444 China

The Al-Si-V system is assessed to understand the phase equilibria of V-containing（3 d transition metal）Al-Si alloys, which are generally of great importance for technical applications. Four annealed alloys were prepared to study the phase equilibria of Al-rich corner（V ≤ 23.3 at.%, Si ≤ 57.6 at.%） in the temperature range of 500-930 ℃. The microstructure and phase constituents of the samples were determined by X-ray diffraction（XRD） and scanning electron microscopy（SEM） equipped with energy dispersive X-ray spectrometer（EDS）, The existence of ternary phase τ（Al（0.6） Si（1.4） V, TiSi2-type） was confirmed with the composition ranging from 17.98 to 18.59 at.% Al and 48.89-49.20 at.% Si. However, it did not equilibrate with fcc（Al） below 868℃, which was determined by differential scanning calorimetry（DSC）. The Si3 V5 appeared in Al58 5 Si（18.3） V（23.2） and Al64 7 Si（20.2） V（15.1） alloys annealed at 500 ℃. It nearly disappeared after3000 h-annealing and its thermodynamic stability was discussed. According to the measured phase relationships, the thermodynamic description of Al-Si-V system was optimized combing with the enthalpies of formation of binary and ternary compounds obtained by density functional theory（DFT）. The Si-V system was modified to obtain the congruent liquidus of Si3 V5 and enthalpy of formation of Si3 V5 and Si2 V with experimental data. By comparing the calculated phase equilibria and phase transitions with experimental data, it showed that a good agreement was reached. The description of Al-Si-V system could be used to guide the development of Al-Si alloys.

关键词： Phase equilibrium Al-Si alloy CALPHAD method Intermetallic compounds enthalpy of formation

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Enthalpies of formation of Noble Metal Binary Alloys Bearing Rh or Ir

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Journal of Materials Science & Technology 2003年第3期19卷 243-246页

作者： YifangOUYANG HongmeiCHEN XiapingZHONG DepartmentofPhysics GuangxiUniversityNanning530004China InternationalCentreforMaterialsPhysics ChineseAcademyofSciencesShengyang110016China GuilinInstituteofTechnology Guilin541004China

The modified embedded atom method proposed by authors has been applied to calculating the enthalpies of formation of random alloys and the ordered intermetallic compounds for noble metal binary systems bearing Rh or Ir. The present results are in good agreement with those of Miedema theory, available experiments and the first-principles quantum mechanics calculations. The present results indicate that Cu-Rh, Cu-lr, Ag-Rh, Ag-lr, Au-Rh, Au-lr, Pd-Rh and Pd-lr systems are repulsive, however, IMi-Rh, Ni-lr, Pt-lr, Pt-Rh and Rh-lr systems form solid solutions and Ni-Rh, Ni-lr and Pt-Rh show ordering tendency.

关键词： Modified embedded atom method enthalpy of formation Binary alloy

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Balanced solubility product and enthalpies of formation of Nb compounds in 0.09 % oriented silicon steel

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Rare Metals 2013年第3期32卷 318-322页

作者： Hui Li Yun-Li Feng Dan Zhang Meng Song Da-Qiang Cang School of Metallurgical and Ecological Engineering University of Science and Technology Beijing School of Metallurgy and Energy Hebei United University

Balance solubility products and enthalpy of for- mation for NbC0.75, NbC0.85, NbC0.88, NbC and NbN in oriented silicon steels were calculated and compared quali- tatively. Meanwhile, the mixing enthalpies of these five Nb compounds were calculated based on Miedema Model. The results show that the solubility products of Nb compounds in ferrite and austenite meet the following relationship, NbC0.75 〉 NbC0.85 〉 NbC0.88 〉 NbC 〉 NbN and NbN has the minimum enthalpy of formation. It indicates that NbN easily precipitate out, but it is more difficult for NbC0.75.

关键词： Oriented silicon steel Nb compounds Solubility formula enthalpy of formation

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Computational Study on Mechanisms of C2H5O2＋OH Reaction and Properties of C2H5O3H Complex

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Chemical Research in Chinese Universities 2017年第4期33卷 623-630页

作者： LIU Yanli CHEN Long CHEN Dongping WANG Weina LIU Fengyi WANG Wenliang Key Laboratory for Macromolecular Science of Shaanxi Province School of Chemistry and Chemical Engineering Shaanxi Normal University Xi "an 710119 P. R. China

A comprehensive theoretical study on the bimolecular reaction of C2H502 with OH radicals was performed at the CCSD（T）/6-311＋＋G（2df2p）//B3LYP/6-311＋G（d,p） level of theory. The calculation results show that C2H5O2 ＋ OH reaction proceeds on both the singlet and the triplet potential energy surfaces（PESs）. On the singlet PES, the favorable pathway is the addition of OH radical to the terminal oxygen atom of C2H5O2 radical, leading to the formation of trioxide C2H5O3H with a barrierless process. Then, the trioxide directly decomposes to the products C2H50 and HO2 radicals. On the triplet PES, the predominant pathways are a and β hydrogen atom abstractions of C2H5O2 radical by OH radical-forming products 3CH3CHO2＋H2O and 3CH2CH2O2＋H2O, and the corresponding bar- tiers are 12.02（3TS8） and 19.19 kJ/mol（3TS9）, respectively. In addition, the comprehensive properties of trioxide C2H503H were investigated for the ftrst time. The results indicate that the trioxide complex RC1 can exist stably in the atmosphere owing to a significantly large and negative enthalpy of formation（-118.44 kJ/mol） as well as a high first excitation energy（5.94 eV）.

关键词： C2H5O2 radical Trioxide C2H5O3H complex Reaction mechanism enthalpy of formation First excited energy

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Standard Enthalpies of formation of Solid Complexes of Lanthanide Nitrates with Alanine

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Journal of Rare Earths 2002年第3期20卷 167-171页

作者：杨旭武陈三平高胜利刘晓华史启祯 NW Univ Xian Dept Chem Shaanxi Key Lab Phys Inorgan Chem Xian 710069 Peoples R China Xian Inst Drug Control Xian 710054 Peoples R China

The combustion energies of fourteen solid complexes of lanthanide nitrate with alanine were determined. The standard enthalpies of combustion, Δ c,coor(s) H °, and standard enthalpies of formation, Δ f,coor(s) H °, were calculated for these complexes. The relationship of Δ c,coor(s) H ° and Δ f,coor(s) H ° with the atomic numbers of the elements in the lanthanide series were examined. The results show that a certain amount of covalence is present in the chemical bond between the lanthanide cations and alanine.

关键词： rare earths lanthanide complex enthalpy of formation

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Determination of Standard Molar Enthalpies of formation for "White Powdery Tungstic Acid" and for Dodecatungstophosphoric Acid by Solution Calorimetry

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Chemical Research in Chinese Universities 1993年第1期9卷 13-17页

作者： WANG Ai-ming CAI Xian-e ZHU Jing Gu Yi-dong(Department of Chemistry, Fudan University, Shanghai 200433)

'White powdery tungstic acid' has been used for preparing various types of tungsten-containing compounds due to its high reactivity. The present paper covers the standard molar enthalpies of formation, △H0/f of three tungsten- containing acids. The values found for 'white powdery tungstic acid' WO3·1. 68H2O, 'yellow tungstic acid' WO3·1. 20H2O and dodecatungstophosphoric acid H3(PW12O40)·25H2O at 298. 15 K were-(1312±1), - (1192±1) and -(18150±13) kJ mol-1, respectively.

关键词： enthalpy of formation Tungstic acid Dodecatungstophosphoric acid Solution calorimetry

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