查找使用阿拉丁产品的科研文献

High performance low-k and wave-transparent cyanate ester resins modified with a novel bismaleimide hollow polymer microsphere

Wenxing Jiang,Xianhong Zhang,Dong Chen,Yuhong Ma,Wantai Yang

High-performance cyanate ester (CE) resins with excellent dielectric properties are highly desired in the fields of information and communication technology . Herein, we present an efficient strategy for the preparation of low- k and wave-transparent CE resins modified with a novel kind of bismaleimide (BMI) hollow polymer microspheres (BMI-HPPs). Benefiting from both the superior properties of BMI and the unique hollow structure, BMI-HPPs can serve as an effective modifier to reduce dielectric constant (ε) of the CE resins and simultaneously improve their toughness. There are plenty of pendant vinyl groups and unreacted maleimide groups on the surface of BMI-HPPs, which could effectively copolymerize with CE monomer , leading to a lower curing temperature and better interfacial compatibility. The BMI-HPPs/CE resin with 7.5 wt% BMI-HPPs exhibited minimum values of ε and dielectric loss (tanδ) (2.46, 0.006) at 16 GHz, much lower than those of the pristine CE resin (2.92, 0.018), and the corresponding wave transmission was 93.8%–97.1% in the frequency range of 15–18 GHz. Moreover, the modified CE resin showed a maximum impact strength of 18.8 kJ/m 2 at 5 wt% loading of BMI-HPPs, which is 64% higher than that of the pristine CE resin. Because of low- k dielectric properties, superior wave-transparent performance and highly enhanced toughness , the BMI-HPPs/CE resins have great potential in the fields of microelectronics and aerospace.

A green approach for enhancing the hydrophobicity of UiO-66(Zr) catalysts for biodiesel production at 298 K

Ahmed S. Abou-Elyazed,Yinyong Sun,Ahmed M. El-Nahas,Ahmed M. Yousif

Recently, the incorporation of hydrophobicity on the surface of UiO-66(Zr) has received much attention due to the deactivation of hydrophilic active sites of UiO-66(Zr) upon water adsorption. In this work, we report UiO-66(Zr) catalysts with an assortment of surface hydrophobicities fabricated by the solvent-free method to elucidate the impact of the environment framing Lewis acid sites on their catalytic activity in the production of fatty acid methyl ester (biodiesel) via the esterification of fatty acids at room temperature with high selectivity (100%) and good recyclability. A detailed structural analysis of the materials by N2 sorption, FT-IR, SEM, XRD, water contact angle measurement, dynamic liquid scattering (DLS), NMR and TGA revealed the fabrication of stearic acid-grafted UiO-66(Zr) catalysts (10SA/UiO-66) with fine particle size and a highly hydrophobic network. 10SA/UiO-66(Zr) with enhanced hydrophobicity exhibited superior catalytic performance in the esterification of a fatty acid with a long alkyl chain compared with conventional solid acid catalysts and even liquid acid catalysts. Detailed kinetic studies corroborated that the adsorption of lipophilic acids at the Lewis acid sites besides the enhancement of wettability between the reactants was facilitated by the hydrophobic environment, thus significantly motivating the esterification reaction at room temperature. Furthermore, 10SA/UiO-66(Zr) showed good catalytic activity in the esterification of oleic acid in the presence of water (∼10% in the light of acid weight).

Na3AMg7(PO4)6 (A = K, Rb and Cs): Structures, properties and theoretical studies of alkali metal magnesium orthophosphates

Jiahao Jiao,Wenqi Jin,Min Zhang,Zhihua Yang,Shilie Pan

Phase Equilibria and Phase Diagrams of the Li+, Na+//Cl–, CO32––H2O System at 323.15 and 348.15 K

Kuo Zhou,Xingfan Wang,Junfang Yang,Fenli Jin,Huan Zhou

The solubility equilibrium of Li+, Na+//Cl–, CO32– −H2O quaternary systems at 323.15 K and 348.15 K was studied via the isothermal solubility equilibrium method, and the complete phase diagrams were obtained including the properties of liquid density and pH. Solid species of LiCl·H2O, Li2CO3, NaCl, and Na2CO3·H2O are found in the quaternary system at 323.15 K and 348.15 K, and one double salt of Li2CO3·Na2CO3 is found at 348.15 K. The liquid phase of two invariant points and five univariant curves at 323.15 and three invariant points and seven univariant curves at 348.15 K in the quaternary system is determined. Li2CO3 covers the largest solid phase region and is hardly influenced by temperature; Li2CO3–NaCl is a stable salt pair, and its cosaturated solubility is the least at the diagonal line of Li2CO3–NaCl.

Permeability of N, P, K-fertilizer nutrient and water vapor through PLA, PLA/PS, and PLA/HA membranes

Xiaonan Deng,Sihong Ye,Kun Liu,Changfeng Li,Fangzhi Liu,Xiaoming Yan

To collect permeability data and establish its database of fertilizer nutrients and water vapor through different polymer membranes for the development of polymer-coated fertilizer, the permeabilities of N-, P-, and K-nutrient from saturated aqueous of urea, NaH2PO4 and KCl solution and the permeability of water vapor through the membranes of poly lactic acid (PLA), its blends with polystyrene (PS), and its composites with humic acid (HA) particles were determined experimentally at the temperatures of 288, 298, and 308 K, respectively. The effects of the addition of PS and HA particles, temperature, and coating thickness on the permeability of fertilizer nutrient and water vapor were investigated. It was found that the addition of PS and HA increased the permeability for both the fertilizer nutrients and water vapor. The increase in temperature raised the permeability of N-, P-, and K-nutrient while decrease the permeability of water vapor in the range studied.

Cage-like P4S3 molecule as promising anode with high capacity and cycling stability for Li+/Na+/K+ storage

Denghu Wei,Jie Yin,Zhicheng Ju,Suyuan Zeng,Haibo Li,Wei Zhao,Yanyan Wei,Huaiyong Li

Phosphorus sulfide cage molecule based on P 4 S 3 was investigated for the first time as anode material for the storage of alkali metal ions (Li + , Na + , K + ). Such P 4 S 3 sample was obtained in a large scale by a simple heating reaction of low-cost rep P and S. X-ray diffraction refinement analysis indicates that P 4 S 3 sample possesses a defect rich molecule crystal structure with S/P atom ratio of 0.74. The P 4 S 3 anode delivered a high reversible capacity of 1266 mAh g −1 for lithium-ion batteries at 0.1 A g −1 and good cycling performance. Experimental results demonstrated that the P 4 S 3 anode undergoes a reversible Li-storage reaction of P 4 S 3  + 11 Li +  + 11 e − ↔ 0.5 Li 4 P 2 S 6  + 3 Li 3 P during cycling. It also exhibited a high capacity of 1002 and 378 mAh g −1 at 0.1 A g −1 for Na + and K + storage, respectively. These properties suggest the promising application of P 4 S 3 anode in high energy batteries.

Solubility Measurement and Correlation of Doxycycline Hyclate in 10 Pure Solvents and Mixtures Solvents at 278.15–323.15 K

Yanmin Shen,Wenju Liu,Chen Sun,Paifeng Shi

The solid–liquid phase equilibrium solubility of doxycycline hyclate (DH) in 10 pure organic solvents and cosolvent mixtures DMF (1) + ethanol (2), DMSO (1) + ethanol (2) and acetone (1) + ethanol (2) at a temperature range from 278.15 to 323.15 K was measured and discussed. The results indicated that the experimental mole fraction (x) of DH in 10 neat solvents followed this order: acrylic acid > acetic acid > 1-butanol > 1-pentanol > tetrahydrofuran > isobutyl alcohol > isopropyl alcohol> propanoic acid > acetone > acetonitrile, and temperature affected obviously the solubility especially in acetic acid. Moreover, the experimental mole fraction (x) of DH increased with mass concentration rising of DMF or DMSO in DMF (1) + ethanol (2) or DMSO (1) + ethanol (2), and decreased gradually with mass concentration rising of acetone in acetone (1) + ethanol (2). The experimental solubility in all solvents was correlated better by the modified Apelblat model according to lower values of RAD and RMSD.

Measurement of Speed of Sound in Methyl Hexanoate from 297.83 to 588.07 K and up to 10 MPa

Junshuai Chen,Qi Zhou,Taotao Zhan,Maogang He,Ying Zhang

Methyl hexanoate, which was found to be the simplest methyl ester to present a strong cool flame behavior, is expected to be one of the main components of biodiesels. Details of the experimental speeds of sound in methyl hexanoate are scarce up to now. Therefore, the speed of sound in liquid methyl hexanoate was measured by the Brillouin light scattering method in the temperature range of 297.83–588.07 K and at pressures of up to 10 MPa. The relative uncertainty of the speed of sound experimental system is estimated to be less than 0.43%, and when considering the impurity of the sample, the relative uncertainty is 0.47%. The variation of the speed of sound with the temperature and pressure was analyzed. Besides, the correlation for the speed of sound as a function of temperature and pressure is presented based on the experimental data. The absolute average of relative deviation between the experimental data and the calculated results is 0.44%.

Rechargeable K-Se batteries based on metal-organic-frameworks-derived porous carbon matrix confined selenium as cathode materials

Xianglong Huang,Qiuju Xu,Wei Gao,Tingting Yang,Renming Zhan,Jianhua Deng,Bingshu Guo,Mengli Tao,Hongdong Liu,Maowen Xu

In this work, porous carbon matrix derived from metal-organic frameworks is synthesized by a facile carbonation process for confining element selenium. The Se/nitrogen-doped porous carbon composite is applied as the cathode for rechargeable K-Se batteries for the first time. The abundant and hierarchical porous structure is advantageous in overcoming the volume expansion problem caused by polyselenides during discharge-charge process. The in-situ nitrogen-doped porous carbon enhances electronic conductivity of the cathode composite material. The electrochemical result shows that the as-obtained Se/nitrogen-doped porous carbon composite with Se content of 53% delivers good rate capacity with coulombic efficiency of nearly ∼90% and a reversible cycling capacity of 327 mA h g −1 at 0.2 C, maintaining about 130 mA h g −1 even after 100 cycles.

Dilution enthalpies of the binary systems (LiBO2 + H2O) and (LiB5O8 + H2O) and the ion interactions at 308.15 K

Yuqi Wang,Linxue Yan,Hua Li,Long Li,Yafei Guo,Tianlong Deng

Microcalorimeter measured the dilution enthalpies of the binary systems (LiBO 2  + H 2 O) and (LiB 5 O 8  + H 2 O) at 308.15 K and 0.1 MPa. Based on the Pitzer theory of electrolytes, their apparent molar enthalpies and the Pitzer single electrolyte parameters at 308.15 K were carried out by fitting the experimental data for the first time. Moreover, the calculated apparent molar enthalpies of LiBO 2 and LiB 5 O 8 aqueous solution according to the Pitzer ion-interaction model were consistent well with the experimental values, manifesting the high reliability of this study.

Co-optimization of Ag and K doping to regulate room-temperature coefficient of resistivity of La0.7Ag0.3-xKxMnO3 films

Xiaokun Zhu,Shuaizhao Jin,Xiaohan Yu,Zhiyuan Yu,Xin Gu,Xiaoli Guan,Kaikai Wu,Yixin Yan,Liming Zhao,Jiamei Han,Jiabin Jiang,Xiang Liu,Xiangming Li

In this study, La 0.7 Ag 0.3- x K x MnO 3 (LAKMO, x = 0.15, 0.16, 0.17, 0.18, and 0.19) films with excellent electrical properties and low surface roughness were prepared on SrTiO 3 ( 0   0   1 ) substrates using the spin-coating method. The crystal structures and ion valence states of the LAKMO films were modified by adjusting the doping amounts of Ag and K. The Jahn–Teller effect and electron–lattice coupling were enhanced with the MnO 6 octahedron undergoes distortion. Moreover, the double-exchange interaction was improved with an increase in the number of Mn 4+ /Mn 3+ ion pairs. Under the influence of these factors, the electrical transport properties especially the temperature coefficient of resistivity ( TCR ) of the LAKMO films can be refined modulated or optimized via A-site Ag and K co-doping. When x  = 0.17, the maximum TCR of LAKMO reached 11.23 % K −1 at 293.23 K. Thus, La 0.7 Ag 0.13 K 0.17 MnO 3 film with a large TCR exhibited excellent thermal properties at room temperature and was considered material for application to uncooled infrared bolometers.

Solid–Liquid Equilibrium of Rebaudioside A in Pure and Binary Mixed Solvents at T = (288.15 to 328.15) K

Behnaz Asadzadeh,Jialun Zhong,Weidong Yan

Solid–liquid equilibrium data of rebaudioside A (a natural sweetener) in nine pure solvents (methanol, ethanol, 1-propanol, 2-propanol, acetonitrile, 2-methoxyethanol, 2-ethoxyethanol, 2-buthoxyethanol, and ethylene glycol) and two binary mixed solvents (methanol + ethanol and 2-methoxyethanol + ethanol) were been measured by high performance liquid chromatography at temperatures ranging from (288.15 to 328.15) K and atmospheric pressure. From the experimental data, it was found that the solubility increased with the rising temperature in all studied solvents. The obtained values for the solubility of rebaudioside A in pure and mixed binary solvents were correlated with modified Apelblat and nonrandom two-liquid models. The results showed that these models can accurately correlate the solubility data obtained in this work. Furthermore, the crystal habits of rebaudioside A in selected solvents were studied.