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91.
Efficient and selective removal of 90Sr is an important process for the safe use of nuclear energy. Herein, we investigate and assess the Sr2+ adsorption properties of a metal-organic framework UiO-66-(COOH)2 functionalized by non-bonded carboxylic groups. This MOF is an exciting class of free carboxylic functionalized MOFs that combine chemical stability with gas sorption, dye elimination, and conductivity. Specifically, we show that uniformly distributed carboxyl and water stability make it accessible for loading Sr2+ without structural changes. The FTIR spectroscopy, PXRD analysis, XPS, and SEM-EDS studies show excellent stability as well as the strong affinity between -COOH active site and Sr2+. This strong coordination interaction guarantees a high adsorption capacity of 114 mg g−1 within 5 h (pH 5 and 298 K). Combined kinetic and thermodynamic studies show that the surface complexation is strong chemisorption and cost-effective spontaneous process (ΔG = −5.49 kJ mol−1~−2.16 kJ mol−1). The fact that UiO-66-(COOH)2 not only possesses a high adsorption capacity, but also enables selectivity to Sr2+ in the presence of similar radius ions Na+ and K+, prefigures its great potential for the practical treatment of radioactive Sr2+ in polluted water. 相似文献
92.
针对物理气相传输(PVT)法生长碳化硅(SiC)晶体,建立了一个二维生长动力学模型研究SiC生长腔内气相组分输运特性,该模型考虑了氩气与气相组分之间的流动耦合,Stefan流和浮力影响.研究表明:在压力较低的情况下,自然对流对气相组分的输运过程影响很小,可以忽略,而当压力增高时,自然对流强度显著增大,不可忽略.其次,随着生长温度升高对流的作用增强,生长腔内输运过程由扩散向对流转变,最终对流主导组分的输运过程.随着压力升高对流作用减弱,扩散为气相组分主要输运方式. 相似文献
93.
Yao Zhang Yu Xue Wei Yuan Wensheng Ma Jinqiang Li Fengming Li 《Acta Mechanica Solida Sinica》2021,34(3):369-380
This paper is concerned with the active control of thermo-mechanical buckling of composite laminated plates using piezoelectric facesheets as actuators.The four... 相似文献
94.
In the large momentum transfer limit, generalized parton distributions can be calculated through a QCD factorization theorem which involves perturbatively calculable hard kernels and light-cone parton distribution amplitudes of hadrons. We illustrate this through the H(q)(x,xi,t) distribution for the pion and the proton, presenting the hard kernels at leading order. As a result, experimental data on the generalized parton distributions in this regime can be used to determine the functional form of the parton distribution amplitudes which has thus far been quite challenging to obtain. Our result can also be used as a constraint in phenomenological generalized parton distribution parametrizations. 相似文献
95.
Yanli Jin Qingying Dou Yange Liu Jianguo Liu Lingling Xu Shuzhong Yuan Xiaoyi Dong 《Optics Communications》2006,266(2):390-392
A dual-stage L-band gain-clamped erbium-doped fiber amplifier (GC-EDFA) by using backward C-band amplified spontaneous emission (ASE) is proposed. Compared with other similar GC-EDFAs, the proposed structure has higher and flatter clamped gain in L-band because of its optimal pump power and EDF length. The flatness from 1570 nm to 1600 nm arrives 0.77 dB, the bandwidth of 3 dB is more than 35 nm and the maximal input signal power arrives −15 dBm. 相似文献
96.
J.-H. Yuan X.-Z. Sang C.-X. Yu L. Rao Y. Han G.-Y. Zhou S.-G. Li L.-T. Hou 《Applied physics. B, Lasers and optics》2011,105(4):685-688
Using the photonic crystal fiber (PCF) with the zero dispersion wavelength of 848 nm for the fundamental mode, the efficient
anti-Stokes signal generations from 645 to 543 nm are realized by pumping in the normal dispersion region. When the pump average
power increases from 200 to 500 mW, the output power of the anti-Stokes signal increases 8.46 times, the power ratio of the
anti-Stokes signal at 543 nm to the residual pump is calculated as 22.6:1, and the conversion efficiency η in the experiment can be up to 46%. Moreover, good optical beam quality of the anti-Stokes signal can be achieved. 相似文献
97.
The reflection and transmission theories of waves in pyroelectric and piezoelectric medium are studied in this paper. In general in an infinite homogeneous pyroelectric medium there are four bulk wave modes: quasi-longitudinal, two quasi-transversal and temperature waves. In an infinite homogeneous piezoelectric medium there are three bulk wave modes: quasi-longitudinal and two quasi-transversal waves. In the reflection and transmission problem there are five complex boundary conditions in the pyroelectric medium and four complex boundary conditions for the piezoelectric medium. In this paper, we find that the surface waves will be revealed in the reflection and transmission wave problem. The surface waves have the same wave vector component with the incident waves on the interface plane. The two dimensional reflection problem of waves at the interface between the semi-infinite pyroelectric medium and vacuum is researched in greater detail and a numerical example is given. 相似文献
98.
DaChao Yuan JiangLong Wang Nian Fu XiaoLin Wu YueJin Ma ShuFang Wang 《中国科学:物理学 力学 天文学(英文版)》2018,(10)
正Transparent conducting oxides(TCOs)have attracted intensive attention because of their broad application in photoelectric devices such as solar cells,light-emitting diodes,and flat-panel displays.Current TCOs used in industry,including tin(IV)oxide(SnO_2),indium oxide(In_2O_3),indium tin oxide(ITO),and zinc oxide(ZnO),are primarily n-type semiconductors[1-3].Suitable p-type TCOs are still being 相似文献
99.
The internal friction of partially Sr-substituted Pr(Ba1?xSrx)2Cu3O7?δ (x = 0, 0.05, 0.1, 0.2, 0.3, and 0.4) ceramics was measured by the vibrating-reed method from liquid nitrogen temperature to room temperature at kilohertz frequencies. The intensity of the internal friction peak, which appears around 250 K, decreases upon Sr doping. The result is explained in terms of a possible combining structural freezing transition of CuO5 square pyramids and oxygen atoms in CuOx chains. Another internal friction peak around 134 K was observed in tetragonal Pr(Ba0.6Sr0.4)2Cu3O7?δ which is temporarily explained by the hopping of holes in the CuO2 layers. 相似文献
100.
工业CT检测对象的大小是不固定的,最大限度地利用已有探测器的成像面积非常重要。采用探测器偏置来获得更大的扫描视野,并推导相应的重建算法。该算法首先使用Parker类型函数对采集到的投影数据中的冗余部分进行加权,然后采用扇束滤波反投影重建算法重建得到断层图像。在实验中使用实际工业CT系统分别采集钢制线对块与铝合金变速器外壳的投影数据进行重建算法的验证,重建结果证明了使用的探测器偏置重建算法的正确性与有效性,且空间分辨率和标准扫描的重建结果保持一致,这个方法可以在工业CT成像上有效使用。 相似文献