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981.
The development of a pH-sensitive nanofibrous sensor could contribute to interesting applications thanks to the combination of the pH-sensitive functionality and the unique characteristics of nanofibres. The effect of the addition of pH-sensitive dyes to the polymer solution is however unknown. Moreover also the halochromic behaviour of the resulting nonwovens can be influenced by this incorporation. Therefore, we studied the production of halochromic nano nonwovens by adding various pH-indicator dyes to a polyamide 6.6 polymer solution prior to electrospinning. Next, the halochromism of two selected dyes (Bromocresol Purple and Brilliant Yellow) was investigated as case studies. Our results show that the pH-indicator addition has no influence on the average fibre diameter. Poorly dissolved dyes cause however instabilities in the process as seen by the droplet formation. The investigated nanofibrous structures showed a clear colour change with a change in pH. This halochromic behaviour was however different from the behaviour of the dye in solution due to dye-fibre interactions. Generally it can be concluded that a nanofibrous pH-sensor can be developed by electrospinning with incorporated pH-indicator dyes. 相似文献
982.
A computational strategy based on comparative molecular fields analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) was performed on a series of the 11H-dibenz[b,e]azepine and dibenz[b,f][1,4]oxazepine derivatives as potent agonists of the human TRPA1 receptor. The CoMFA and CoMSIA models resulting from a 21 molecule training set gave r2(cv) values of 0.631 and 0.542 and r2 values of 0.986 and 0.981, respectively. The statistically significant models were validated by a test set of five compounds with predictive r2(pred). values of 0.967 and 0.981 for CoMFA and CoMSIA, respectively. A systemic external validation was also performed on the established models. The information obtained from 3D counter maps could facilitate the design of more potent human TRPA1 receptor agonists. 相似文献
983.
Metastasis is the main cause of cancer mortality. During this process, cancer cells dislodge from a primary tumor, enter the circulation and form secondary tumors in distal organs. It is poorly understood how these cells manage to cross the tight syncytium of endothelial cells that lines the capillaries. Such capillary transmigration would require a drastic change in cell shape. We have therefore developed a microfluidic platform to study the transmigration of cancer cells. The device consists of an array of microchannels mimicking the confined spaces encountered. A thin glass coverslip bottom allows high resolution imaging of cell dynamics. We show that nuclear deformation is a critical and rate-limiting step for transmigration of highly metastatic human breast cancer cells. Transmigration was significantly reduced following the treatment with a protein methyltransferase inhibitor, suggesting that chromatin condensation might play an important role. Since transmigration is critical for cancer metastasis, this new platform may be useful for developing improved cancer therapies. 相似文献
984.
山东蒙阴金刚石多晶的显微红外光谱研究及其成因意义 总被引:2,自引:0,他引:2
山东蒙阴金刚石多晶可划分为多角刻面状和浑圆状金刚石多晶两大类,它们的显微红外光谱研究结果表明,金刚石多晶中的氮含量较低,介于16.69~72.81μg.g-1之间,且同一金刚石多晶的不同金刚石晶粒(或部位)中的氮含量不相同;刻面状金刚石多晶均为ⅠaAB型,且A心的浓度大于B心的浓度。浑圆状金刚石多晶也多为ⅠaAB型,但具有更高浓度的B心,且存在少数同时包含单替代氮、A心和B心的浑圆状金刚石多晶;金刚石多晶不是在金刚石颗粒的成核阶段所形成的,而是在金刚石长大期间或金刚石颗粒形成后的某个特殊条件下聚集而成;山东蒙阴金刚石多晶可能形成于氮浓度较低的较深部地幔。同时,多角刻面状金刚石多晶的形成时间稍晚于金刚石单晶体,浑圆状金刚石多晶的形成时间明显早于金刚石单晶体。 相似文献
985.
Qian J Chen Y Wu L Cao Y Ai X Yang H 《Chemical communications (Cambridge, England)》2012,48(56):7070-7072
A Sb/C nanocomposite was synthesized and found to deliver a reversible 3 Na storage capacity of 610 mA h g(-1), a strong rate capability at a very high current of 2000 mA g(-1) and a long-term cycling stability with 94% capacity retention over 100 cycles, offering practical feasibility as a high capacity and cycling-stable anode for room temperature Na-ion batteries. 相似文献
986.
987.
Xiuhong Pan Jianding Yu Yan Liu Shinichi Yoda Minghui Zhang Fei Ai Fei Jin Huimei Yu Weiqing Jin 《Journal of luminescence》2012,132(4):1025-1029
Er3+ doped TiO2–La2O3 glasses modified by ZrO2 have been successfully fabricated by the containerless method with incorporated Yb3+ ions as sensitizers. Under the excitation of 980 and 808 nm diode lasers, visible emissions centered at 534, 554 and 674 nm are observed, which are assigned to the Er3+ transitions of 2H11/2→4I15/2, 4S3/2→4I15/2 and 4F9/2→4I15/2, respectively. The emission signals are so strong that they can be observed by naked eyes even at pumping power as low as 20 mW. Measurements of pump-power dependent intensity and time-resolved decay behavior of upconversion luminescence show that two-photon excited state absorption (ESA) and energy transfer (ET) between rare earth ions are the predominant mechanisms for upconversion emissions. Besides, the intensity of upconversion luminescence has been enhanced by increasing the concentration of ZrO2 in these rare earth doped bulk titanate glasses. 相似文献
988.
Wenhe Du Zhongmin Yao Daosen Liu Chengjiang Cai Xiufeng Du Ruibo Ai 《Journal of Russian Laser Research》2012,33(1):90-97
Satellite laser communication holds the potential for high-bandwidth communication, but the atmosphere can significantly affect
the capability of this type of communication systems for satellite-toground and ground-to-satellite data links to transfer
information consistently and operate effectively. Usually the influence of atmosphere on satellite laser communication is
investigated based on the Kolmogorov turbulence model. However, both increasing experimental evidence and theoretical investigations
have shown that the Kolmogorov theory is sometimes incomplete to describe the atmospheric statistics properly, in particular,
in some portions of the atmosphere. Considering a non-Kolmogorov turbulent power spectrum with power law −5 that describes the refractive-index fluctuations in the atmosphere above 6 km, we calculate the scintillation index of a
lowest-order Gaussian-beam wave under the weak-fluctuation condition. Then, considering a combined power spectrum of refractiveindex
fluctuations and using the expression obtained, we analyze the joint influence of the Kolmogorov turbulence from the ground
to 6 km and non-Kolmogorov turbulence above 6 km on the scintillation indices of laser beams used in ground-to-satellite and
satellite-to-ground laser communication links. We show that the scintillation index in satellite laser communication is equal
to the sum of the scintillation indices induced by the Kolmogorov turbulence from ground to 6 km and that caused by the non-Kolmogorov
turbulence above 6 km. Also we investigate variations of the scintillation index with the beam radius on the transmitter,
wavelength, the radial distance, and zenith angle. Finally, comparing the scintillation index induced by these two turbulences
with the conventional results, we show that the scintillation index induced by these two turbulences is a bit smaller than
the conventional results. 相似文献
989.
Compact fiber optic accelerometer 总被引:1,自引:0,他引:1
A compact fiber optic accelerometer based on a Michelson interferometer is proposed and demonstrated. In the proposed system, the sensing element consists of two single-mode fibers glued together by epoxy, which then act as a simple supported beam. By demodulating the optical phase shift, the acceleration is determined as proportional to the force applied on the central position of the two single-mode fibers. This simple model is able to calculate the sensitivity and the resonant frequency of the compact accelerometer. The experimental results show that the sensitivity and the resonant frequency of the accelerometer are 0.42 rad/g and 600 Hz, respectively. 相似文献
990.
Xiong L Fletcher AM Davies SG Norman SE Hardacre C Compton RG 《Chemical communications (Cambridge, England)》2012,48(46):5784-5786
The electrode potentials for the two one electron oxidations of 1,2-diferrocenylethylene (bisferrocene, BF) were studied relative to that of the one electrode oxidation of decamethylferrocene in a variety of RTILs. The difference in these potentials was found to be very sensitive to the anion component of the ionic liquid showing the scope of these solutes as 'designer media' to tune the thermodynamic properties of solutes dissolved in them. 相似文献