JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Yao-Dong Liu,Xiao-Qiang Song,Du Kang,Chang-Zhi Yin,Yi-Yang Cai,Jia-Qing Yang,Wen Lei,Wen-Zhong Lu
The Ba 1- x Sr x Cu 2 Ge 2 O 7 was successfully obtained through the solid-state reaction method, with single-phase BaCu 2 Ge 2 O 7 formed at 850 °C. Scanning electron microscopy analysis revealed the excellent chemical compatibility of Ba 1- x Sr x Cu 2 Ge 2 O 7 with silver. The properties of Ba 1- x Sr x Cu 2 Ge 2 O 7 ceramics were explained using the P-V-L theory. The ε r-corr decreased with the polarization rate (Σχ u * N b u ) and ion polarization of the unit cell. The Q×f increased with the chemical bond strength and lattice energy (U cal ), particularly the lattice energy of the Ge-O bond (U(Ge-O)). The τ f exhibited an opposite trend to the Q×f value and was influenced by the U(Cu-O) and susceptibility of the Cu-O bond (χ(Cu-O)). Sintering at 875 °C for 3 h yielded optimal microwave dielectric performance for Ba 1- x Sr x Cu 2 Ge 2 O 7 ceramics, with observed values of ε r = 9.26 ± 0.14, Q×f = 85,660 ± 4200 GHz, and τ f = −15.6 ± 1.1 ppm/°C at x = 0.10. These promising microwave dielectric properties make Ba 1- x Sr x Cu 2 Ge 2 O 7 a potential candidate for LTCC material applications.
研究领域:
材料科学
·
物理学
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DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
·
2023
·
IF 6
Yuzhong Shi,Jinqiu Fu,Yingying Wang,Yihang Hou,Rongxi Guo,Mengyang Cai,Yajie Zhang,Hanjie Ying,Pengpeng Yang,Keke Zhang
Nylon nF is a type of bio-based Nylon, whose raw materials NH 2 -(CH 2 ) n -NH 2 and 2,5-furandicarboxylic acid (FDCA) are both prepared by biological methods. The Nylon nF salts (PAnF salts) are the monomer salts before the polymerization of Nylon nF, whose product quality has a significant impact on the properties of Nylon nF. In this study, Nylon nF salts of FDCA and seven NH 2 -(CH 2 ) n -NH 2 diamines were synthesized. The crystal structures and thermodynamic behaviors of these Nylon salts were determined and analyzed by single crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), and thermogravimetric analysis-differential scanning calorimetry (TG-DSC). Based on the analysis of melting point and solubility data, it was found that there is a significant even–odd effect between Nylon nF salts (n = 4–10). Moreover, the lattice energy and solvation energy in methanol of these Nylon salts were calculated by Materials Studio (MS) and Gaussian , respectively. The results indicated that there was also an even–odd effect in the lattice energy of Nylon nF salts. It is speculated that these even–odd phenomena were related to the symmetry of the ligand diamines and the stacking mode of Nylon salts. The study of the even–odd effect is significant in predicting and designing the physicochemical properties of cocrystals.
研究领域:
材料科学
·
化学
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DOI
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2019
·Vol. 138
·期 2
·1633-1640
·
IF 2.471
Yi Xin,Hu Jiugang,Sun Min,Man Xueyu,Zhang Yunran,Liu Shijun
In this work, the thermal stability of CuCl 2 , CoCl 2 , MnCl 2 , and their corresponding hydrates was studied by combining with calorimetry and lattice energy calculation. The dissolution enthalpies of both anhydrates and hydrates in water with different molalities at 298.15 K were measured to calculate the standard molar enthalpies of formation. The hydration enthalpies and the lattice energies were calculated to disclose the stabilities of the compounds, indicating that the MnCl 2 ·4H 2 O has the highest stability among the three hydrates. Meanwhile, the detailed thermal decomposition behaviors were evaluated with differential scanning calorimetry and thermogravimetric analysis. For CuCl 2 ·2H 2 O, the crystal water is lost by one step directly with the temperature ranges from 350 to 410 K. The decomposition process contains four steps for CoCl 2 ·6H 2 O and obtains its monohydrate in the temperature range from 320 to 479 K. For MnCl 2 ·4H 2 O, two thermal decomposition steps occur from 325 to 500 K, while two consecutive peaks with no clear boundary indicate that the complex reactions appear.
研究领域:
化学热力学
·
材料科学
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2016
·Vol. 28
·期 2
·1597-1604
·
IF 1.798
Yang Z. L.,Pan H. L.,Jiang X. S.,Wu H. T.
Low loss microwave dielectric ceramics Zn 0.92 Co 0.08 ZrNb 2 O 8 with wolframite structure were prepared by the solid state method. Sintering characteristics, phase composition and microwave dielectric properties were investigated systematically. X-ray diffraction results showed that all samples exhibited a wolframite structure. Rietveld refinement was used to analyze the crystal structure. Based on the lattice parameters, the bond ionicity, the lattice energy, the bond energy and the coefficient of thermal expansion were calculated to evaluate the structural characteristics. The ε
r
values could be strongly dependent on the bond ionicity of the Nb–O bonds. The Q·j values were main affected by the lattice energy and the bond energy of the Nb–O bonds. As for the τ
f
values, it could be mainly affected by the coefficient of thermal expansion of Zn/Co–O bonds. At the sintering temperature of 1200 °C, Zn 0.92 Co 0.08 ZrNb 2 O 8 ceramics exhibited the excellent microwave properties of ε
r
= 27.10, Q·f = 61,036 GHz (at 8.54 GHz) and τ
f
= −9.81 ppm/°C. These results demonstrated that Zn 0.92 Co 0.08 ZrNb 2 O 8 ceramics could be promising candidate materials for the application of highly selective microwave ceramic resonators and filters.
研究领域:
材料科学
·
电子工程
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DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2018
·
IF 3.794
Y.H. Zhang,J.J. Sun,N. Dai,Z.C. Wu,H.T. Wu,C.H. Yang
A new kind of low-temperature fired Eu 2 Zr 3 (MoO 4 ) 9 ceramic was fabricated by conventional solid-state reaction method. The mixed powders was calcined at 600 ℃ and the samples were sintered at 500 ℃ –700 ℃ for 4 h. X-ray diffraction analysis and Rietveld refinement indicated that Eu 2 Zr 3 (MoO 4 ) 9 belonged to a trigonal system with space group R-3c. Bond ionicity, lattice energy and bond energy of the ceramic were calculated by the complex chemical bond theory. Microwave dielectric properties were determined at microwave frequencies of 9.7–14.7 GHz by a network analyzer. Far infrared spectra indicated the main contribution to polarization for Eu 2 Zr 3 (MoO 4 ) 9 ceramics was the absorption of structural phonon oscillation. The ceramic sintered at 600 ℃ for 4 h exhibited the best dielectric properties with a relative permittivity ( ε r ) of 10.75, a quality factor ( Q·f ) of 74,900 GHz and a temperature coefficient of resonance frequency ( τ f ) of -8.88 ppm/℃.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2025
·
IF 6.2
Yuan-Bin Chen,Ling Tang,Xiuyuan Su
Low-temperature sintered microwave dielectric ceramics are gaining increasing attention for next-generation wireless communication systems, particularly within the 6 G frequency range. However, materials that simultaneously exhibit ultra-low dielectric loss and low sintering temperatures remain scarce. In this study, Nd 2 [Zr 1-X (Bi 0.5 Ta 0.5 ) X ] 3 (MoO 4 ) 9 ceramics were prepared via a conventional solid-state reaction method and exhibited a single-phase structure with a trigonal symmetry (space group R 3 ¯ C, No. 167). The optimal sample at x = 0.11 sintered at 750 ℃ showed excellent performance: ε r = 11.4, Q×f = 186,300 ± 8900 GHz, and τ f = –42.9 ppm/℃. The elevated Q×f value is chiefly ascribed to increased lattice energy, with its variation more plausibly arising from intrinsic effects within the material. The dielectric constant (εᵣ), analyzed using the Clausius–Mosotti equation, was predominantly influenced by ionic polarizability. According to P–V–L theory, the effective bond strength f iNd–O played a major role in determining εᵣ, while τ f was governed by the bond energy and thermal expansion behavior of Mo–O bonds. Raman spectroscopy further confirmed the structure–property relationships. These results suggest that B-site substitution with (Bi 0.5 Ta 0.5 ) 4+ not only promotes densification and increases lattice energy, but also maintains thermal stability, thereby enhancing Q×f without compromising τ f . This system offers strong potential for integration into future microwave dielectric components.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2017
·
IF 3.133
J.X. Bi,C.F. Xing,Y.H. Zhang,C.H. Yang,H.T. Wu
Wolframite-structured Zn 1−x Ni x ZrNb 2 O 8 (0 ≤ x ≤ 0.1) ceramics were synthesized by the conventional solid-state method. The effects of Ni 2+ substitution on sintering characteristic, crystal structure, and microwave dielectric properties of ZnZrNb 2 O 8 samples were systematically studied. The relationship among bond ionicity, lattice energy, thermal expansion coefficient and microwave dielectric properties was also investigated by the complex chemical bond theory. The dielectric constant of Zn 1−x Ni x ZrNb 2 O 8 ceramics sintered at 1150 °C slightly decreases from 28.06 to 26.35 with the increasing Ni 2+ content, which can be explained by the variation of bond ionicity and polarizability. Raman scattering spectra also reveal that the increase in Ni 2+ content leads to the shift in all the vibration modes and the variation of ionicity in Nb O bond. The Q · f values increases from about 40,000 to 60,000 GHz with the increasing Ni 2+ content, which can be explained by the variation of lattice energy. As for τ f value, it is shifted to positive direction, which can be explained in term of the variation in Nb-site bond energy. In addition, the thermal expansion coefficient plays little effect on the temperature stability of ceramics. Typically, the Zn 0.96 Ni 0.04 ZrNb 2 O 8 samples sintered at 1150 °C exhibit excellent properties with ε r = 27.10, Q · f = 62,700 GHz and τ f = −14.72 ppm/°C.
研究领域:
材料科学
·
物理学
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产品关联
DOI
高影响因子
SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2022
·
IF 7.305
X.K. Tian,T.X. Xu,J. Yan,S.C. Lin,C.Y. Zhao
The cyclic stability enhancement of the CaO/CaCO 3 thermochemical energy storage system is crucial for high-temperature thermal utilization of solar energy. In this study, we successfully enhance the long-term durability of calcium-looping composites by co-doping TiO 2 and MgCl 2 based on lattice energy and phase combination/separation mechanism. According to molecular dynamics simulations of metallic oxides, TiO 2 shows higher thermal stability and better doping effects in calcium-looping materials. Further experiments indicate that the phase combination mechanism acting on high-valance metallic oxides like TiO 2 can promote cyclic stability of calcium-looping materials. The calcium-based composite doped with 10 mol% TiO 2 prepared by wet-mixing method exhibits high energy storage performance in 15 cycles. MgCl 2 is also used as a dopant to improve cyclic stability of the calcium-based composite in long-term cycles further. The energy storage performance of the composite doped with 5 mol% TiO 2 and 5 mol% MgCl 2 is superior to single-doped composites. The average effective conversion ratio is 0.54 in 100 cycles and the energy storage densities are close to 1000 kJ/kg in most of the calcination/carbonation cycles. Microstructure characterizations indicate that the co-doped composite has abundant micropores and smaller particles with the more uniform size distribution. The modification mechanism at atomic scale will serve as guidelines for dopant selection preliminarily, and the novel TiO 2 /MgCl 2 co-doped calcium-based composite is promising for long-term industrial applications, such as high-temperature thermal utilization of solar energy.
研究领域:
能源材料科学
·
太阳能利用技术
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DOI
高影响因子
CRYSTENGCOMM
·
2017
·Vol. 19
·期 30
·4345-4354
·
IF 3.474
Meng Liu,Chuming Yin,Peng Chen,Mingtao Zhang,Sean Parkin,Panpan Zhou,Tonglei Li,Faquan Yu,Sihui Long
Chlorine can participate in numerous interactions such as halogen bonding, hydrogen bonding, and London dispersion in the solid state. In this work, we report the influence of a chlorine substituent on the polymorphism of a potential anticancer drug, 4-chloro-phenylanthranilic acid (CPAA). Three polymorphs have been discovered for this compound, and the three forms were characterized by single-crystal X-ray diffraction, power X-ray diffraction (PXRD), FT-IR, and Raman spectroscopy. Both conformational flexibility of the molecule and the sp2CH⋯Cl hydrogen bond seem to lead to the polymorphism of the system. The phase behavior was investigated by differential scanning calorimetry (DSC), with the conclusion that form II converts to III upon heating. A conformational scan shows the conformational minima corresponds to the conformers existing in the polymorphs. Lattice energy calculations show energies of −106.70, −104.72, and −194.42 kJ mol−1 for forms I to III, providing information on relative stability for each form. Hirshfeld analysis revealed that intermolecular interactions such as H⋯H, C⋯H, H⋯Cl, and H⋯O contribute to the stability of the crystal forms.
研究领域:
药物化学
·
晶体学
·
物理化学
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DOI
高影响因子
CRYSTENGCOMM
·
2024
·Vol. 26
·期 7
·943-950
·
IF 2.6
Jinqiu Fu,Mengyang Cai,Yuzhong Shi,Yihang Hou,Rongxi Guo,Chiyi Wang,Jingjing Zhao,Wei Zhuang,Hanjie Ying,Pengpeng Yang,Keke Zhang
L-Alanyl-L-glutamine (Ala–Gln) is a dipeptide which is widely used in medical and nutritional fields. Two new crystalline forms (form III and form IV) and a DMSO solvate form (SDMSO) of Ala–Gln were discovered in this study, which were distinguished from the known forms by Raman spectroscopy and powder X-ray diffraction (PXRD). Single crystal structures of the three new solid forms were obtained. Moreover, the crystal structure data of known forms: form II, dihydrate form (2H) and ethanol solvate form (SEtOH), which have not been reported to the best of our knowledge, were solved. The results showed that there were four kinds of molecular arrangements and frameworks in the Ala–Gln solid forms. The comparison of the molecular arrangements and cell parameters indicated that the forms III, 2H and SEtOH were isomorphic. The hydrogen bonding network of the DMSO solvate was different from those of forms II, III and IV. By comparing the bulk density, lattice energy and thermal analysis results of the three polymorphs of Ala–Gln, the order of bulk density and lattice energy was consistent with the decomposition enthalpy. Besides that, it was found that the crystal shape of the solvates can be retained after solvent removal.
研究领域:
药学
·
晶体学
·
材料科学
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产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2018
·Vol. 102
·期 7
·4092-4102
·
IF 2.956
Yunhui Zhang,Haitao Wu
La 2 (Zr 1− x Ti x ) 3 (MoO 4 ) 9 (0 ≤ x ≤ 0.1) ceramics were prepared by the traditional solid-state reaction method. XRD analysis showed that La 2 (Zr 1− x Ti x ) 3 (MoO 4 ) 9 (0 ≤ x ≤ 0.1) ceramics belonged to a trigonal system. Based on the chemical bond theory, the consequences of bond energy, bond ionicity, lattice energy, and thermal expansion coefficient of ceramics on microwave dielectric properties were discussed. As Ti 4+ addition was increased, the reduction in dielectric constant was ascribed to the fact that the polarizability of Ti 4+ is smaller than Zr 4+ , and the downward trend was related to the bond ionicity. Besides, the tendency of Q·f value depended on the packing fraction and the lattice energy. The improvement in τ f value, the increase in bond energy, and the decrease in the coefficient of thermal expansion were all correlated. The far-infrared spectra implied that the absorptions of structural phonon oscillation were the main reason for the maximum polarization contribution. La 2 (Zr 0.92 Ti 0.08 ) 3 (MoO 4 ) 9 ceramics sintered at 750°C for 4 hours exhibited the best dielectric properties ( ε r = 10.33, Q·f = 80 658 GHz, and τ f = 3.48 ppm/°C).
研究领域:
材料科学
·
陶瓷工程
·
电气工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Liang Shi,Rui Peng,Huaiwu Zhang,Cheng Liu,Gongwen Gan,Xiaolei Shi,Xueying Wang
CaTi 1-x (Mg 1/2 W 1/2 ) x O 3 (x = 0, 0.02, 0.04, 0.06, 0.08) dielectric ceramics were synthesized via the traditional solid-state reaction method. Crystal structure and microwave dielectric properties of CaTi 1-x (Mg 1/2 W 1/2 ) x O 3 system were systematically investigated based on chemistry bond theory (P–V-L theory) for the first time. The pure perovskite phase was obtained for all doped samples, as confirmed through the XRD and Rietveld refinement results. The lattice characteristics were closely related to the microwave dielectric properties. The bond ionicity, lattice energy, and bond energy affected the dielectric constant, quality factor, and temperature stability of the ceramic material. Through the use of (Mg 1/2 W 1/2 ) 4+ doped on B-site, the CaTi 1-x (Mg 1/2 W 1/2 ) x O 3 system can maintain a high dielectric constant (ε r > 100) while effectively reducing the τ f value from 800 ppm/ ° C to less than 300 ppm/ ° C and improving the Q × f value to 9650 GHz (at 3.76 GHz).
研究领域:
材料科学
·
陶瓷工程
·
微波工程
·
固体化学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）