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271.
Chung‐Lun Wu Cheng‐Hsuan Hsieh Gong‐Ru Lin Wen‐Chun Chi Yi‐Jen Chiu Yuan‐Yao Lin Yung‐Jr Hung Min‐Hsiung Shih Ann‐Kuo Chu Chao‐Kuei Lee 《Annalen der Physik》2017,529(3)
A tantalum pentoxide‐based (Ta2O5‐based) micro‐ring all‐optical modulator was fabricated. The refractive index inside the micro‐ring cavity was modified using the Kerr effect by injecting a pumped pulse. The transmittance of the ring resonator was controlled to achieve all‐optical modulation at the wavelength of the injected probe. When 12 GHz pulses with a peak power of 1.2 W were coupled in the ring cavity, the transmission spectrum of the Ta2O5 resonator was red‐shifted by 0.04 nm because of the Kerr effect. The relationship between the modulation depth and gap of the Ta2O5 directional coupler is discussed. An optimized gap of 1100 nm was obtained, and a maximum buildup factor of 11.7 with 84% modulation depth was achieved. The nonlinear refractive index of Ta2O5 at 1.55 μm was estimated as 3.4 × 10?14 cm2/W based on the Kerr effect, which is almost an order of magnitude higher than that of Si3N4. All results indicate that Ta2O5 has potential for use in nonlinear waveguide applications with modulation speeds as high as tens of GHz.
272.
Chao‐Zhi Zhang Ting Li Yang Yuan Cheng‐Yue Gu Meng‐Xiao Niu Hui Cao 《Journal of Physical Organic Chemistry》2017,30(5)
Substituents significantly affect optical properties of organic compounds. In this study, a series of organic compounds were synthesized. Ultraviolet‐visible and cyclic voltammetry spectra were determined. The relationships between the number of π electron in an aryl ring and the redshift (and molecular orbital energy levels) were studied. To investigate mechanisms of the bromine substituent effects, theoretical calculations were carried out. Ultraviolet‐visible spectra of bromine‐containing compounds exhibit obvious redshifts (0.04‐0.17 eV) of the maximal absorption wavelengths and enhanced absorbance (11%‐57%) compared with corresponding reference compounds. The lowest unoccupied and highest occupied molecular orbital energy levels of compounds containing bromine substituents are 0.05 to 0.60 and 0.02 to 0.40 eV lower than that of corresponding reference compounds. On the whole, the redshifts and the reduced molecular orbital energy levels caused by bromine substituent decrease with the increase in the number of π electron in an aryl ring. The effects would be attributed to strong p‐π conjugation between p electron in the bromine substituent and π electrons in aryl rings. Therefore, this paper suggests a useful way for tuning optical absorption and molecular orbital energy levels of aryl compounds. 相似文献
273.
Renal Clearable Luminescent WSe2 for Radioprotection of Nontargeted Tissues during Radiotherapy 下载免费PDF全文
Haixia Liu Junying Wang Yaqi Jing Jiang Yang Xueting Bai Xiaoyu Mu Fujuan Xu Xuhui Xue Lingfang Liu Yuan‐Ming Sun Qiang Liu Haitao Dai Changlong Liu Xiao‐Dong Zhang 《Particle & Particle Systems Characterization》2017,34(6)
High‐energy ionizing radiation is widely used in medical diagnosis and cancer radiation therapy. However, high‐energy radiation can also impose significant damages in healthy tissues during medical treatments via direct DNA damages and indirect damages from production of reactive oxygen species (ROS). Therefore, it is urgent to develop highly effective radioprotectants with low toxicities that can meet the increasing needs for alleviating the adverse effects from cancer radiation therapy and nuclear emergency. In this work, strongly catalytic ultrasmall (sub‐5 nm) cysteine‐protected WSe2 dots are employed to protect healthy tissues against radiation via diminishing radiation‐induced free radicals. The WSe2 dots with high surface activities can recover radiation‐induced DNA damages and eliminate the excessive ROS generated from radiation. In vivo experiments confirm that the survival rate of mice treated with WSe2 dots is significantly elevated with radiation damages postponed under exposure to high‐dose ionizing radiation. Furthermore, the free radicals in major organs and hematological system can be appreciably omitted, suggesting their unique role as free radical scavengers. These WSe2 dots in ultrasmall size show rapid renal clearance of ≈74% injection dose via urine excretion in 24 h and do not cause any apparent toxicity in vivo for up to 30 d. 相似文献
274.
275.
276.
Wei J Liu Z Chai Z Yuan J Lian J Shen GX 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2007,186(2):358-363
In this paper, a digital wireless transmission system based on 802.11b standard for magnetic resonance imaging (MRI) application is designed and built for the first time to eliminate the interference aroused by coil array cables. The analysis shows that the wireless receiver has a very high sensitivity to detect MRI signals. The modulation technique of differential quadrature phase shift keyed (DQPSK) can be applied to MRI data transmission with rate of 2 Mbps and bandwidth of 2 MHz. The bench test verifies that this wireless link has a dynamic range over 86 dB supporting up to 3 T MRI system data transmission. The 2D spin echo imaging of phantom is performed and the SNR of the image obtained by the wireless transmission can be comparable with that got by the coaxial cables. 相似文献
277.
A composite-cavity-based Fabry-Perot interferometric strain sensor system is proposed to gain the minimum cross sensitivity to temperature and a high multiplexing capability at the same time. The interrogation of the sensor system is based on a white-light interferometric technology, and the demodulation is achieved by analyzing the coherence spectra. A demonstration system with two sensors is presented and tested. 相似文献
278.
279.
Though various integrable
hierarchies of evolution equations were obtained by choosing
proper U in zero-curvature equation Ut-Vx+[U,V]=0, but in this paper, a new integrable hierarchy possessing
bi-Hamiltonian structure is worked out
by selecting V with spectral potentials.
Then its expanding Lax integrable model of the hierarchy possessing a simple
Hamiltonian operator \widetilde{J} is presented
by constructing a subalgebra
\widetilde{G } of the loop algebra \widetilde A2. As
linear expansions of the above-mentioned integrable hierarchy and
its expanding Lax integrable model with respect to their
dimensional numbers, their (2+1)-dimensional forms are derived
from a (2+1)-dimensional zero-curvature equation. 相似文献
280.
Jinyong Kuang Jingxian Zhang Langhua Huang Jianhua Rong Dingsheng Yuan 《Solid State Communications》2005,136(1):6-10
A novel blue-emitting long-lasting phosphor Sr3Al10SiO20:Eu2+,Ho3+ is prepared by the conventional high-temperature solid-state technique and their luminescent properties are investigated. XRD, photoluminescence (PL) and thermoluminescence (TL) are used to characterize the synthesized phosphors. These phosphors are well crystallized by calcinations at 1500-1600 °C for 3 h. The phosphor emits blue light and shows long-lasting phosphorescence after it is excited with 254/365 nm ultraviolet light. TL curves reveal the introduction of Ho3+ ions into the Sr3Al10SiO20:Eu2+ host produces a highly dense trap level at appropriate depth, which is the origin of the long-lasting phosphorescence in this kind of material. The long-lasting phosphorescence lasts for nearly 6 h in the light perception of the dark-adapted human eye (0.32 mcd/m2). All the results indicate that this phosphor has promising potential practical applications. 相似文献