CHEMICAL ENGINEERING JOURNAL
·
2015
·
IF 4.321
Lu Qi,Xianghai Meng,Rui Zhang,Haiyan Liu,Chunming Xu,Zhichang Liu,Peter A.A. Klusener
Droplet size distribution (DSD) and mean droplet size of chloroaluminate ionic liquid (IL)–heptane dispersion in a stirred vessel were investigated as a model system for the composite ionic liquid/hydrocarbon system applied in the commercial isobutane alkylation process. Focused beam reflectance measurement was used to identify the phase inversion, and particle video microscope (PVM) was employed to measure the DSD of IL-continuous dispersions. The effects of agitation speed and dispersed phase holdup on the DSD and mean droplet size were investigated. Phase inversion was found at a heptane hold-up of just above 0.5. The observed DSDs could be described well by logarithmic normal distributions in spite of variable operating conditions. The DSDs appeared to be more or less independent of the dispersed phase holdup ( ϕ heptane ⩾ 0.3) at the same agitation speed. A semi-empirical correlation based on Shinnar theory was proposed to predict the droplet mean size in the impeller region for the IL-continuous dispersion, and the predicted value agreed well with the experimental data. This work will be a good basis to predict the dispersion behavior under process conditions.
研究领域:
化学工程
·
流体力学
·
多相系统
·
过程工程
·
胶体与界面科学
✓ 已验证
DOI
高影响因子
SCRIPTA MATERIALIA
·
2019
·
IF 4.539
Qingshuang Ma,Feng Lan,Xinhua Li,Zunfeng Du,Huijun Li,Zongqing Ma
In this work, the superconducting properties of FeSe 1−x S x with 0 ≤ x ≤ 0.5 were studied. With S doping, T c is enhanced and shows a dome shape in the studied composition range. XRD measurements demonstrate that S substituting Se sites introduces positive chemical pressure, which can suppress the orbital ordering, manifesting as the decrease of T s . Hall measurements demonstrate that S doping can effectively tune the charge carriers and make hole-type carriers predominant. However, no maxing T c is obtained as T s vanishes in FeSe 0.7 S 0.3 , indicating the nematic order has no universal influence on the superconductivity of FeSe system.
研究领域:
凝聚态物理
·
材料科学
·
低温物理学
·
强关联电子系统
✓ 已验证
DOI
高影响因子
POLYMER
·
2017
·
IF 3.684
Yanzhi Zhao,Juying Zhou,Fuhou Lei,Haitang Xu,Jianfang Lu,Zaiying Huang,Qin Huang,Pengfei Li
In this work, amphiphilic acrylicpimaric acid polyglycol ester (APAPG) was synthesized by steglich esterification method. The structure transformation and aggregation behaviors of APAPG in water were investigated by Rayleigh light scattering (RLS) technique in a heating and cooling cycle. For concentration above critical micelle concentration (CMC), a reversible transition from micelle to aggregation was observed. The structure transformation process involved irreversible aggregation and disaggregation processes at low temperature and a reversible aggregation process at high temperature when the concentration closed to CMC. Accordingly, the information about each structure transformation behavior in the concentration far below CMC during heating process including individual unimers, aggregation and disaggregation were thoroughly revealed. However, the structure transformation behavior is irreversible in the cooling process. The structure transformation and aggregation behaviors were assessed by dynamic light scattering (DLS), microcalorimetry and scanning electron microscopy (SEM) techniques. The results indicate that the RLS technique can provide detailed information about structural evolution at molecular level of polymer chains.
研究领域:
高分子化学
·
胶体与界面化学
·
药物递送系统
·
生物材料
·
纳米医学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CHEMISTRY
·
2013
·Vol. 31
·期 6
·745-751
·
IF 0.917
Yifei Wang,Daoyong Chen
Here we report novel shear-sensitive polymeric large compound micelles (LCMs) formed by self-assembly of glutathione end-capped poly(4-vinylpyridine) (GP4VP) in water containing 4 vol% methanol. The amphiphile prefers to form the kinetically stabilized LCMs due to the small length ratio of the hydrophilic part to the hydrophobic part; the encapsulation of the hydrophilic part within LCMs causes only a small enthalpy loss from a thermodynamic view. Sheared by vortex flows generated by vigorous stir, the LCMs evolve to thick wall vesicles, thin wall vesicles, broken vesicles and "pearl-necklace" structures consecutively. The high flexibility of the LCMs and the internal tension caused by the encapsulation of the hydrophilic part are responsible for the high shear sensitivity of the LCMs.
研究领域:
高分子化学
·
胶体与界面科学
·
纳米材料
·
自组装
·
流变学
✓ 已验证
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2014
·
IF 2.633
Guang-Rui Xu,Miao-Jun Xu,Bin Li
The cyclotriphosphazene-based epoxy resin hexa-[4-(glycidyloxycarbonyl) phenoxy]cyclotriphosphazene defined as CTP-EP was successfully synthesized from hexachlorocyclotriphosphazene, p -hydroxybenzaldehyde and epichlorohydrin. Its chemical structure was characterized by Fourier transform infrared (FTIR) spectroscopy, 1 H NMR, 13 C NMR and 31 P NMR spectroscopy . The prepared compound was cured with diamino diphenyl methane (DDM), diamino diphenyl sulfone (DDS) and m -phenylenediamine (mPDA), respectively. The flame retardant properties, thermal degradation behavior and flame retardant mechanism of the cured CTP-EP were investigated. The LOI values of all cured CTP-EP samples increased from 19.9% for cured diglycidyl ether of bisphenol-A (DGEBA) to above 30% and successfully passed UL-94 V-0 rating, which demonstrated that the prepared CTP-EP thermoset exhibited excellent flame retardancy. The dynamic mechanical thermal analysis (DMA) test demonstrated that the glass transition temperature ( Tg ) enhanced from 155 °C for the cured DGEBA to 167 °C for CTP-EP thermoset . The results of thermogravimetric analysis/infrared spectrometry (TG-IR) tests suggested that the phosphazene group and high aromatic content in CTP-EP thermoset stimulated the dehydration of the matrix at earlier degradation process and the formation of char layer, which retarded the release of pyrolysis gas and enhanced the thermal stability of the cured CTP-EP at high temperature. The cone calorimeter tests (cone) test revealed that heat release rate (HRR), total heat release (THR), smoke production rate (SPR) and total heat production (TSP) of the cured CTP-EP decreased significantly compared with the cured DGEBA. The scanning electron microscopy (SEM) results showed that the phosphazene groups in CTP-EP obviously stimulated the formation of the intumescent, compact and stable char layer, which enhanced the flame retardancy of the matrix during combustion. Consequently, the underlying materials were protected from further degradation and combustion during a fire and result in the efficient flame retardancy of CTP-EP thermoset.
研究领域:
高分子化学
·
材料科学
·
热分析
·
阻燃材料
·
聚合物化学
✓ 已验证
DOI
高影响因子
Small
·
2023
·Vol. 20
·期 9
·2306758
·
IF 13.3
Chen Li,Ke Liu,Dequan Jiang,Huacai Yan,En Chen,Yingying Ma,Haoming Cheng,Ting Wen,Binbin Yue,Yonggang Wang
Polymorphic phase transition is an essential phenomenon in condensed matter that the physical properties of materials may undergo significant changes due to the structural transformation. Phase transition has thus become an important means and dimension for regulating material properties. Herein, this study demonstrates the pressure-induced multi-transition of both structure and physical properties in violet phosphorus, a novel phosphorus allotrope. Under compression, violet phosphorus undergoes sequential polymorphic phase transitions. Concomitant with the first phase transition, violet phosphorus exhibits emergent insulator–metal transition, superconductivity, and dramatic switching from positive to negative photoconductivity. Remarkably, the resistance of violet phosphorus shows a sudden drop of around 10 7 along with the phase transition. In addition, piezochromism from translucent red to opaque black and suppression of photoluminescence are observed upon compression. Of particular interest is that the sample irreversibly transforms into black phosphorus with a pronounced discrepancy in physical properties from the pristine violet phosphorus after decompression. The abundant polymorphic transitions and property changes in violet phosphorus have significant implications for designing novel pressure-responsive electronic/optoelectronic devices and exploring concealed polymorphic transition materials.
研究领域:
凝聚态物理
·
材料科学
·
高压物理
·
半导体物理
·
光学材料
·
相变动力学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2019
·
IF 4.175
Liang Zheng,Wenjie Zhang,Qi Wang,Hong Zhang,Zhou Yu,Cuihua Cheng,Yong Zhang,Ming Lei,Yong Zhao
MgB 2 bulks with NaCl doping amount ranging from 0–30 at% have been prepared by hot pressed sintering process . With the increase of NaCl doping amount, the c axis lattice parameter of MgB 2 monotonously increases, indicating the substitution of Mg atoms by larger Na atoms. Meanwhile, the intensity of diffraction peaks of both NaCl and impurity phase of MgO increases. More compact morphology was found in the NaCl doped MgB 2 samples. The critical transition temperature ( T c ) decreases from 38.2 K to 36.8 K with the increase of NaCl doping amount from 0 to 30 at%, and the corresponding transition width of T c (Δ T c ) increases from 0.5 K to 1.8 K. When the doping amount of NaCl is not exceeding 10 at%, the J c value is about 10 6 A/cm 2 at 4.2 K, 3 T, and 5 × 10 5 A/cm 2 at 10 K, 3T. J c performance of the 5 at% NaCl doped MgB 2 sample (NC05) reaches 6.8 × 10 5 A/cm 2 at 20 K, 2T, which improves approximately 20% compared to the pure one, attributing to the better grain connectivity of MgB 2 and enhancement of flux pinning force by NaCl doping.
研究领域:
凝聚态物理
·
材料科学
·
超导材料
·
无机固体化学
·
功能陶瓷
✓ 已验证
DOI
高影响因子
MACROMOLECULAR RAPID COMMUNICATIONS
·
2018
·Vol. 39
·期 11
·1800048
·
IF 4.441
Shuang Pan,Mingjing Zhu,Luze He,Hongdong Zhang,Feng Qiu,Zhiqun Lin,Juan Peng
An intriguing morphological transition from poly(3-hexylthiophene) (P3HT) 1D nanofibers to 2D nanoribbons enabled by the addition of a series of alkylthiols is reported. First, P3HT 1D nanofibers are formed due to strong anisotropic π–π stacking between planar rigid backbones. Upon the addition of alkylthiols, P3HT nanofibers are transformed into nanoribbons associated with the crystallographic transition from edge-on orientation to flat-on orientation. The content of alkylthiols has a great influence on the P3HT morphology in the solution. The mechanism of such a morphological transformation is discussed based on the interaction between alkylthiols and P3HT chains. This work offers an effective strategy to tailor the crystal morphology and dimension of P3HT, which not only improves the understanding of P3HT crystallization but also may enable such discovery into conjugated polymer-based optoelectronic devices.
研究领域:
高分子化学
·
材料科学
·
凝聚态物理
·
纳米科技
·
有机电子学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·Vol. 50
·期 12
·21859-21868
·
IF 5.1
Haiyan Guo,Kuibao Zhang,Yuxiang Li
In this work, the irradiation response of A 2 Ti 2 O 7 (A represents rare earth elements of Gd, Dy, Ho, Er, Yb and Nd) series ceramics were systematically studied under 3 MeV Au 2+ ions. The structural changes pre- and post-irradiation were characterized using X-ray diffraction (XRD), grazing incidence X-ray diffraction (GIXRD) and Raman spectroscopy . After heavy ion irradiation , all the samples undergo structural transformations from ordered pyrochlore to disordered fluorite and then to amorphous phase. The sample surface became fully amorphous when exposed to the maximum irradiation dose. The 5RETO high-entropy pyrochlore exhibits the lowest rate of amorphization during the process of structural transformation. The cation radius ratio and mixed entropy are the primary factors influencing amorphization rate. The cation radius ratio shows a strong positive correlation with the amorphization rate, while the mixed entropy demonstrates a weak negative correlation with the amorphization rate. The cation radius ratio can thus serve as a reliable indicator for predicting the radiation resistance of high-entropy pyrochlore ceramics.
研究领域:
材料科学
·
核材料
·
固态化学
·
辐射效应
·
无机非金属材料
✓ 已验证
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 82
·52024-52029
·
IF 3.108
Xiao-Fen Sun,Zhongxia Wang,Wei-Qiang Liao,Peng-Fei Li,Jixing Gao,Yi-Yang Huang,Hai-Peng Chen,Heng-Yun Ye,Yi Zhang
In this paper, three new hybrid phase transition compounds, [Hmpy]CdBr3 (1, Hmpy = N-methylpyrrolidinuium cation), [Hmpy]2CdBr4 (2) and [Hmpy]3CdBr3·CdBr4 (3), were synthetized by means of regulating the ratio of reactants. Systematic characterizations consisting of variable temperature X-ray single crystal diffraction, differential scanning calorimetry (DSC) and dielectric measurements reveal that 1 with infinite one-dimensional (1D) [CdBr3]n− chains undergoes a phase transition around 278 K; 2 with isolated [CdBr4]2− tetrahedrons exhibits a high-temperature phase transition close to 367 K, accompanied by prominent switchable dielectric behavior. Interestingly, 1D [CdBr3]n− chains and isolated [CdBr4]2− tetrahedrons both exist in 3, associated with a phase transition at 320 K. The phase transitions in the three compounds are originated from the order-disorder transitions of the Hmpy cation. It is expected that our finding would promote the development of hybrid dielectric transition materials with adjustable properties.
研究领域:
材料化学
·
凝聚态物理
·
晶体工程
·
功能材料
·
介电材料
✓ 已验证
DOI
高影响因子
POLYMER BULLETIN
·
2024
·Vol. 81
·期 11
·10175-10185
·
IF 3.1
Hu Jing,Wang Guoqiang
Polylactic acid (PLA) is a kind of polyester from biomass. To increase the ductility of PLA, melt blending was used to prepare the polylactic acid/poly(butylene diglycolate) blends in this study. The effect of poly(butylene diglycolate) (PBD) on the thermal, crystallization, tensile, and dynamic mechanical properties of PLA was investigated. The blend containing 30 wt% PBD has a substantially improved elongation at break (79%) due to the lower glass transition temperature of PBD compared to PLA. The results indicated that PLA and PBD exhibited partial compatibility, which was confirmed by dynamic mechanical analysis (DMA) and scanning electron microscope (SEM). Fourier transform infrared spectroscopy (FTIR) analysis showed there is the interaction between PLA and PBD. In summary, the incorporation of PBD resulted in improved mechanical properties, indicating potential for applications requiring enhanced ductility.
研究领域:
高分子材料科学
·
生物医用材料
·
聚合物共混
·
材料力学性能
·
可降解高分子
✓ 已验证
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2018
·Vol. 20
·期 27
·18455-18462
·
IF 3.906
Xiangyang Duan,Chao Ma,Wentao Jin,Xiaoman Ma,Lu’an Guo,Su-Huai Wei,Jinying Yu,Yelong Wu
A simple and efficient top-down strategy, the chemical vapor etching method, is reported for synthesizing corrugated ZnO nano/micro rods (NRs). The stabilization mechanism of this unique nanostructure has been determined through a combination of aberration-corrected field emission scanning electron microscopy, high-resolution transmission electron microscopy, and first-principles calculations. The experimental data are in good agreement with the theoretical calculations, and a remarkable nonpolar-to-polar surface faceting transition is demonstrated. The corrugated-shaped structure results from the remarkable stability of the defect-induced reconstructions (O vacancy, Zn–Zn dimer), which makes the high-index polar {301} and {10} planes lower in energy compared to the nonpolar {100} plane. Based on the results of first-principles surface calculations, a general formula is established to provide an accurate description of the unusual size effect of the length of the corrugated unit vs. the NR diameter, and it also offers direct explanations for certain experimental observations. The present study deepens our atomic-level understanding of the detailed structure and stability of polar surface decorated corrugated ZnO NRs, and points to a viable path towards designing polar-stable wurtzite structures.
研究领域:
材料科学
·
纳米科技
·
表面科学
·
凝聚态物理
·
计算材料学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）