ADVANCED FUNCTIONAL MATERIALS
·
2012
·Vol. 23
·期 2
·198-203
·
IF 10.179
Tianru Wu,Guqiao Ding,Honglie Shen,Haomin Wang,Lei Sun,Da Jiang,Xiaoming Xie,Mianheng Jiang
A simple but efficient strategy to synthesize millimeter-sized graphene single crystal grains by regulating the supply of reactants in the chemical vapor deposition (CVD) process is demonstrated. Polystyrene is used as a carbon source. Pulse heating on the carbon source is utilized to minimize the nucleation density of graphene on copper foil, while a gradual increase in the temperature of the carbon source and the flow rate of hydrogen is adapted to drive the continuous growth of the graphene grains. As a result, the nucleation density of graphene grain can be controlled to as low as ≈100 nuclei/cm 2 , and a single crystal grain can grow up to dimensions of ≈1.2 mm. Raman spectroscopy, transmission electron microscopy (TEM), and electrical-transport measurements show that the graphene grains obtained are of high quality. The strategy presented provides very good controllability and enables the possibility of large graphene single crystals, which is of vital importance for practical applications.
研究领域:
材料科学
·
物理化学
✓ 已验证
DOI
高影响因子
PHYSICS IN MEDICINE AND BIOLOGY
·
2022
·Vol. 67
·期 19
·195005
·
IF 4.174
Qianwen Huang,Yun Zhou,Ke Li,Lei Pan,Yuan Liu,Jingfeng Bai,Xiang Ji
Objective. This study is aimed to explore the effects of vascular and sonication parameters on ex vivo vessel sonicated by high-intensity focused ultrasound. Approach. The vascular phantom embedding the polyolefin tube or ex vivo vessel was sonicated. The vascular phantom with 1.6 and 3.2 mm tubes was sonicated at three acoustic powers (2.0, 3.5, 5.3 W). The occlusion level of post-sonication tubes was evaluated using ultrasound imaging. The vascular phantom with the ex vivo abdominal aorta of rabbit for three flow rates (0, 5, 10 cm s−1) was sonicated at two acoustic powers (3.5 and 5.3 W). Different distances between focus and posterior wall (2, 4, 6 mm) and cooling times (0 and 10 s) were also evaluated. The diameter of the sonicated vessel was measured by B-mode imaging and microscopic photography. Histological examination was performed for the sonicated vessels. Main results. For the 5 cm s−1 flow rate, the contraction index of vascular diameter (Dc) with 5.3 W and 10 s cooling time at 2 mm distance was 39 ± 9% (n = 9). With the same parameters except for 0 cm s−1 flow rate, the Dc was increased to 45 ± 7% (n = 4). At 3.5 W, the Dc with 5 cm s−1 flow rate was 23 ± 15% (n = 4). The distance and cooling time influenced the lesion along the vessel wall. Significance. This study has demonstrated the flow rate and acoustic power have the great impact on the vessel contraction. Besides, the larger lesion covering the vessel wall would promote the vessel contraction. And the in vivo validation is required in the future study.
研究领域:
生物医学工程
·
超声技术
·
血管研究
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF FOOD ENGINEERING
·
2022
·
IF 6.203
Yan Pang,Yao Lu,Qiang Zhou,Xiang Wang,Ju Wang,Mengqi Li,Zhaomiao Liu
The size and the dispersibility of droplets are the significant factors that determine the performance in applications of the emulsion droplets, which are controlled by the breakup characteristics of interfaces. In this paper, a four-phase glass capillary device is used to generate three-layer wrapped (O 1 /O 2 /W/O 3 ) emulsion droplets stably, recording the evolution of interfaces to investigate the breakup characteristics of interfaces under different flow rates. Based on the breakup form of interfaces, the phase diagram which is recorded by the flow rate ratios ( α , β ) shows the distribution of different generation modes, including Jetting Tubing (JT), Dripping Tubing (DT), Dripping (D), Narrow Jetting (NJ) and Widen Jetting (WJ). The interfaces are recorded with time in different generation modes in this study, focusing on the generation details of DJ, D, and NJ mode, where the droplet generates with the stable periodic motion. The inner droplets do not influence the generation modes but provide the interactions of the interfaces in some cases, especially on the neck diameter of the outer interface. In DT mode, a larger flow rate ratio intensifies the fluctuation of the interface, while it pulls the neck of the inner interface and the outer one to the similar position along the flow direction. In NJ mode, the relation between prediction length and the experimental one follows a similar scaling law to single droplets with various coefficients.
研究领域:
化学工程
·
流体力学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Jianfeng Hu,Sixing Zhang,Heqing Fu,Jinqing Qu,Zhengguo Zhang
Solid-liquid phase change materials (PCMs) have broad potential but suffer from leakage problems and unreasonable thermal conductivity, resulting in low utilization efficiency. In this study, using Guar Gum (GG) as large frame and graphene oxide (GO) or SiO 2 aerogel microchip as small frame, thermal conductivity strengthening PCMs (GG-C-PEG) and thermal conductivity weakening PCMs (GG-I-PEG) were prepared after loading polyethylene glycol (PEG). In-depth characterizations turned out that the phase change enthalpy retention was close to 100% of PEG . In particular, the composites achieved 0.94 W/(m·K) of enhanced thermal conductivity and exhibited a reduced thermal conductivity of 0.11 W/(m·K). Simultaneously, the mass of the PCMs remained above 94.08% when heated at 80 °C for 45 min and the loss of melting enthalpy was less than 6.11% after 100 cycles, indicating outstanding stability in shape and performance during the heating–cooling cycles. To further utilize of solar energy, GG-C-PEG exhibited great photothermal conversion efficiency reaching 83.67%. Moreover, inspired by Tai Chi culture, a novel device that could control the heat flow rate from minimum to maximum by utilizing different thermal conductivity properties of the two types of PCMs was designed, taking composite PCMs further into practical scenarios.
研究领域:
材料科学
·
热能工程
·
太阳能利用
·
复合材料
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）