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991.
应用拉曼光谱技术研究了长波紫外(Ultraviolet-A,UV-A)辐射对Ⅰ型胶原的损伤,检测了Ⅰ型胶原及其经过90min的UV-A辐射后的拉曼光谱,得到了一个较完整的Ⅰ型胶原紫外损伤机制。实验结果表明:90min的UV-A辐射导致Ⅰ型胶原分子内氢键断裂、氢键体系发生变化,肽链的螺旋度减少,逐渐解螺旋,无规卷曲等无序构象增加。此外,UV-A辐射使Ⅰ型胶原分子内脯氨酸的羟基化程度降低。这些变化必然会引起Ⅰ型胶原三螺旋结构的损伤,并导致皮肤光老化过程中组织内胶原纤维的破坏。 相似文献
992.
Jin L Fang Y Hu P Zhai Y Wang E Dong S 《Chemical communications (Cambridge, England)》2012,48(15):2101-2103
A novel inorganic-organic hybrid film structure based on polyoxometalate and conventional organic dye has been fabricated, whose fluorescence can be reversibly switched using the electrochromic component to activate or suppress the related fluorescence quenching mechanism upon applying reduction or oxidation potentials of polyoxometalates. 相似文献
993.
Linuan Yin Ying Li Jun Wang Yu Zhai Yumei Kong Jingqun Gao Guangxi Han Ping Fan 《Journal of luminescence》2012,132(11):3010-3018
In this progress report, seven kinds of novel carefully designed and fabricated up-conversion luminescence agents, Er3+:Y3Al5O12, Er3+:YbnY3?nAl5O12, Er3+:Y3BaAl5?aO12, Er3+:Y3GabAl5?bO12, Er3+:Y3Al5NxO12?x, Er3+:Y3Al5FyO12?y and Er3+:YbnY3?nBaGabAl5?a?bNxFyO12?x?y, are successfully synthesized using sol–gel methods. After that, their corresponding photocatalysts, Er3+:Y3Al5O12/TiO2, Er3+:YbnY3?nAl5O12/TiO2, Er3+:Y3BaAl5?aO12/TiO2, Er3+:Y3GabAl5?bO12/TiO2, Er3+:Y3Al5NxO12?x/TiO2, Er3+:Y3Al5FyO12?y/TiO2 and Er3+:YbnY3?nBaGabAl5?a?bNxFyO12?x?y/TiO2, are also prepared by sol–gel coating process. The obtained up-conversion luminescence agents and photocatalysts were characterized by using XRD, XPS, SEM, UV–vis and fluorescence spectrophotometer. Synchronously, several kinds of organic dyes are used to test their photocatalytic degradation using prepared photocatalysts. It indicates that the up-conversion luminescence ability of Er3+:Y3Al5O12 can be improved obviously through doping of some elements. And then, the photocatalytic activity of TiO2 is markedly enhanced by modified up-conversion luminescence agents which can transform much visible light into ultraviolet light. 相似文献
994.
Chen W Wei Y Huang C Wang X Shen H Zhai S Xu S Li B Chen Z Zhang G 《Optics letters》2012,37(11):1968-1970
We demonstrated an efficient second-Stokes Raman laser emission at 1313 nm based on self-frequency stimulated Raman scattering from a diode-end-pumped actively Q-switched YVO(4)/Nd:YVO(4)/YVO(4) laser at 1064 nm for the first time, to the authors' knowledge. A double-end diffusion-bonded Nd:YVO(4) composite crystal was adopted for sufficiently improving the thermal lensing effect in the course of self-frequency stimulated Raman scattering operation. With an incident pump power of 14.6 W and a pulse repetition (PRR) of 40 kHz, a maximum average output power of 2.34 W was obtained, corresponding to an optical-to-optical conversion efficiency of 16%. Pulse width and peak power were 1.2 ns and 49 kW, respectively. 相似文献
995.
Statefinder diagnostic is a useful method which can distinguish one dark energy model from the others. In this paper, we apply
this method to the GCG model with and without viscosity. It is shown that the evolving trajectory of the viscous GCG model
in the s–r diagram is not only quite different from the model without viscosity but also different from other dark energy models. 相似文献
996.
在商用0.35 μm互补金属氧化物半导体工艺上制备了两种栅氧化层厚度(tox)的条形栅、环形栅和半环形栅N沟道金属氧化物半导体 (n-channel metal oxide semiconductor, 简记为NMOS) 晶体管, 并进行了2000 Gy(Si)的总剂量辐射效应实验. 实验结果显示, 栅氧厚度对阈值电压漂移的影响大于栅氧厚度的3次方. 对于tox为11 nm的低压NMOS晶体管, 通过环形栅或半环形栅的加固方式能将其抗总剂量辐射能力从300 Gy(Si)提高到2000 Gy(Si)以上; 而对于tox为26 nm的高压NMOS晶体管, 通过环栅或半环栅的加固方式, 则只能在低于1000 Gy(Si)的总剂量下, 一定程度地抑制截止漏电流的增加. 作为两种不同的版图加固方式, 环形栅和半环形栅对同一tox的NMOS器件加固效果类似, 环形栅的加固效果略优于半环形栅. 对于上述实验结果, 进行了理论分析并阐释了产生这些现象的原因.
关键词:
环形栅
半环形栅
总剂量
辐射效应 相似文献
997.
998.
999.
Effective response in nonlinear spherical coated composites under external AC and DC electric fields
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By using the perturbation method,effective nonlinear direct current(DC) and alternating current(AC) responses of nonlinear composites with spherical coated inclusions randomly embedded in a host medium are studied under the action of an external electric field E a = E 0 + E 1 sin ωt + E 3 sin 3ωt with different amplitudes and frequencies.The local potentials of composites at all harmonics are given in the inclusion particles and the host regions.All effective nonlinear responses to composites and the relationship between the effective nonlinear responses at all harmonics are also deduced for the spherical coated inclusions in a dilute limit. 相似文献
1000.
We report the phase diagram of the lead‐free ternary (Bi0.5Na0.5)TiO3–(Bi0.5K0.5)TiO3–(K0.5Na0.5)NbO3 (BNT–BKT–KNN) system and study the switching characteristics of the morphotropic phase boundary (MPB). The addition of KNN intrinsically changes the structural nature of the system with shift of MPB type from (I) to (II), and also adjusts the depolarization temperature (Td) to room temperature. Accordingly, a high electrostrictive response with large electrostrictive coefficient Q33 (~0.022–0.027 m4/C2) and a good thermostability comparable with that of traditional Pb‐based electrostrictors was achieved in MPB (II) compositions. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献