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91.
《International Journal of Hydrogen Energy》2019,44(59):30965-30973
CuS/CdS(H)/CdS(C) photocatalysts were synthesized via the hydrothermal method by employing thiourea, Cd(CH3COO)2·3H2O and copper 1,4-benzenedicarboxylate MOF (CuBDC). The photocatalysts were characterized by XRD, XPS, BET, TEM and UV–vis diffuse reflectance spectra. Interestingly, hexagonal CdS (CdS(H)) and cubic CdS (CdS(C)) were formed with phase junctions in one step when CuBDC was introduced in the synthesis process, in addition, CuS nanoparticles were deposited on CdS. However, only hexagonal CdS was obtained without CuBDC. It demonstrated that CuBDC was not only the precursor of CuS but also the structural modifier for CdS. With the reduction of re-combination of photo-induced electrons and holes caused by phase junctions and the enhancement of visible-light absorptions due to the loading of CuS, all CuS/CdS(H)/CdS(C) photocatalysts had higher photocurrent densities under visible-light irradiation, and consequently the higher rates of H2 production than pure CdS(H). Typically, the catalyst with 2.89 wt% of Cu showed a highest rate of H2 evolution at 2042 μmol/g/h. 相似文献
92.
Rachel E. Sheldon Chipo Mashayamombe Shao-Qing Shi Robert E. Garfield Anatoly Shmygol Andrew M. Blanks Hugo A. van den Berg 《Journal of the Royal Society Interface》2014,11(101)
The smooth muscle cells of the uterus contract in unison during delivery. These cells achieve coordinated activity via electrical connections called gap junctions which consist of aggregated connexin proteins such as connexin43 and connexin45. The density of gap junctions governs the excitability of the myometrium (among other factors). An increase in gap junction density occurs immediately prior to parturition. We extend a mathematical model of the myometrium by incorporating the voltage-dependence of gap junctions that has been demonstrated in the experimental literature. Two functional subtypes exist, corresponding to systems with predominantly connexin43 and predominantly connexin45, respectively. Our simulation results indicate that the gap junction protein connexin45 acts as a negative modulator of uterine excitability, and hence, activity. A network with a higher proportion of connexin45 relative to connexin43 is unable to excite every cell. Connexin45 has much more rapid gating kinetics than connexin43 which we show limits the maximum duration of a local burst of activity. We propose that this effect regulates the degree of synchronous excitation attained during a contraction. Our results support the hypothesis that as labour approaches, connexin45 is downregulated to allow action potentials to spread more readily through the myometrium. 相似文献
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通过红外热像仪测量Ga As功率放大器芯片的结温可知,温度最高点出现在芯片的栅条上,红外热像仪的放大倍数会导致芯片结温的差异性,正确选择测量的距离系数和放大倍数,可以提高红外热像仪的测温准确性。采用Flotherm软件仿真,并与试验值比较,两者的误差低于6%,由此验证了仿真的可靠性。运用Flotherm软件对T/R组件的散热片优化处理可知,散热片底板对温度影响较小,随着散热片数目的增加,温度逐渐降低,直到散热片的数目阻碍了空气流动,温度开始上升。 相似文献
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Xiaoda Wang Chunying Zhu Taotao Fu Youguang Ma 《American Institute of Chemical Engineers》2015,61(3):1081-1091
Bubble breakup with permanent obstruction in an asymmetric microfluidic T‐junction is investigated experimentally. The breakup process of bubbles can be divided into three stages: squeezing, transition, and pinch‐off stages. In the squeezing stage, the thinning of the bubble neck is mainly controlled by the velocity of the fluid flowing into the T‐junction, and the increase of the liquid viscosity can promote this process. In the transition stage, the minimum width of bubble neck decreases linearly with time. In the pinch‐off stage, the effect of the velocity of the fluid flowing into the T‐junction on the thinning of the bubble neck becomes weaker, and the increase of the liquid viscosity would delay this process. The evolution of the minimum width of the bubble neck with the remaining time before the breakup can be scaled by a power–law relationship. The bubble length has little influence on the whole breakup process of bubbles. © 2014 American Institute of Chemical Engineers AIChE J, 61: 1081–1091, 2015 相似文献
97.
目前风电变流器可靠性评估,无法在考虑实际风速、气温等外部环境长期随机变化的情况下考虑基频结温波动对变流器可靠性的影响。文中提出一种结温迭代算法,可以快速数值计算出功率模块结温。该方法与结温电热仿真方法相比,在保证计算精度的同时能大大缩短计算时间。文中以1.2MW直驱风力发电系统为例,利用提出的结温数值计算方法并结合实际风速和气温数据快速计算整年器件结温,采用Bayerer寿命模型和线性累计损伤理论实现了计入基频结温波动的风电变流器可靠性评估。最后还对可靠性计算结果进行了验证,对比分析了机侧和网侧变流器的可靠性差异、低频和基频结温波动对变流器可靠性的影响。结果表明,大功率直驱风力发电系统,机侧变流器可靠性问题更为严重,且基频结温波动对变流器可靠性的影响不容忽视。 相似文献
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100.
针对传统功分器的不足,提出了一种改进型波导E-T结功分器。通过三维电磁仿真软件CST对其进行了建模仿真,得到一个合理的设计方案,该结构具有高隔离度、低插入损耗、小体积、宽频带等优点。加工的实物经测试在12~17 GHz的频率范围内,该功分器的插入损耗<0.12 dB,回波损耗>18 dB,隔离度>15 dB,具有良好的工程应用价值。 相似文献