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1.
利用紫外-可见(Uv-Vis)光谱和荧光光谱研究了超声波照射激活纳米二氧化硅(SiO2)粒子对牛血清白蛋白(BSA)分子的损伤,并考查了超声波照射时间、纳米SiO2粉末加入量、溶液酸度和超声波照射功率等因素对BSA分子损伤程度的影响.结果表明,对于体系温度为(37.0±0.2)℃和浓度为1.0×10-5mol·-1的BSA溶液,UV-Vis光谱显示,随着超声波照射时间,纳米SiO2粉末加入量,溶液pH值和照射功率的增大呈现出越来越明显的增色效应.然而,BSA溶液的荧光光谱却随着上述因素的增大呈现出越来越明显的猝灭现象.此外,还初步探讨了超声波照射激活纳米siO2粒子对BSA分子损伤的机理,认为是声致发光或高热激发使纳米siO2粒子产生·OH自由基,进而损伤溶液中的BSA分子.这一研究结果对声催化方法应用于临床治疗肿瘤以及纳米药物的开发具有一定的指导意义.  相似文献   

2.
SiO2分子的基态(X1A1)结构与分析势能函数   总被引:4,自引:3,他引:4       下载免费PDF全文
应用群论及原子分子反应静力学方法推导了SiO2分子的电子态及其离解极限,采用B3P86方法,在6-311G**水平上,优化出SiO2基态分子稳定构型为单重态的C2V构型,其平衡核间距Re=RSi-O=0.1587 nm,∠OSiO=111.2°,能量为-440.4392 a.u..同时计算出基态的简正振动频率:对称伸缩振动频率v(B2)=945.4cm-1,弯曲振动频率v(A1)=273.5 cm-1和反对称伸缩振动频率v(A1)=1362.9cm-1.在此基础上,使用多体项展式理论方法,导出了基态SiO2分子的全空间解析势能函数,该势能函数准确再现了SiO2(C2V)平衡结构.  相似文献   

3.
采用非平衡分子动力学方法研究了环状聚合物及其对应的线性链熔体在启动剪切场下的结构与流变特性.模拟结果显示:低剪切速率下(■1×10~(-4)τ~(-1))环状链分子体系相比于同分子量的线性链体系并没有出现明显的过冲现象.该结果表明,在启动剪切场下环状分子与其对应的线性链相比较表现出了更弱的分子形变,同时模拟结果也与最近实验观察的结果一致.为了进一步探究这种现象背后的分子机理,在分子层面统计了不同流场强度下,链段的长度和取向角分布随着应变的演化,统计结果证明了环状聚合物分子链段弱的形变是导致其弱的剪切变稀和峰值应变的主要因素.本文还给出了过冲点和稳态在不同剪切速率下环状分子与其对应的线性链的流变特性(过冲应变、最大应力、最大黏性和稳态黏性)、结构和取向参数与维森伯格数(Wi_R)所满足的标度关系.  相似文献   

4.
根据群论及原子分子反应静力学的有关原理,推导出SiO,SiS分子基态(X1∑+)的合理离解极限.使用密度泛函方法中的B3P LY和B3P86方法,在6-311++G(3df,2pd)和D95(3df,2pd)基组下对SiO,SiS分子的基态进行结构优化计算,使用优选的B3P86/D95(3df,2pd)对基态单点能扫描计算.然后用最小二秉法拟合Murrell-Sorbie函数,得到对应的势能函数参数及光谱常数.结果表明,采用Murrell-Sorbie函数计算所得的光谱常教与实验结果符合的很好,能精确地描述SiO,SiS分子基态的势能函数.  相似文献   

5.
根据群论及原子分子反应静力学的有关原理,推导出SiO,SiS分子基态(X1Σ+)的合理离解极限.使用密度泛函方法中的B3P LY和B3P86方法,在6-311++G(3df,2pd)和D95(3df,2pd)基组下对SiO,SiS分子的基态进行结构优化计算,使用优选的B3P86/D95(3df,2pd)对基态单点能扫描计算.然后用最小二乘法拟合Murrell-Sorbie函数,得到对应的势能函数参数及光谱常数.结果表明,采用Murrell-Sorbie函数计算所得的光谱常数与实验结果符合的很好,能精确地描述SiO,SiS分子基态的势能函数.  相似文献   

6.
通过对动力学对称性的介绍,引出构造分子体系Hamiltonian的方法,并介绍李代数方法处理分子"振动-振动耦合"、"振动-转动耦合"Hamiltonian的一般步骤.还以HCO分子体系为例,说明如何选取特定的群链来构造Hamiltonian,并论证了对于该体系群链的唯一性.最后还对一些李代数方法在分子光谱中的其他应用(例如局域模,多原子分子的振转光谱研究)作了初步的介绍,并对于这一方法的不足和局限性做了论述.  相似文献   

7.
利用溶胶-凝胶技术自主合成了一种具有优良光学特性和高热稳定性的有机/无机复合芯层材料.这种功能材料的分子中含有有机柔性侧链,可形成环氧交联.与无机SiO2-TiO2体系相比,具有较高的热光系数(量级为10-4/K),以及更好的成膜性和可加工性.通过与实验室自行配制的P(MMA-GMA)包层材料相匹配,设计制备了基于这种有机/无机复合功能材料的倒脊型波导马赫-曾德尔型热光开关.器件的波导与热电极性能良好.插入损耗为10dB,驱动功率15mW,开关时间小于1ms,消光比15dB.  相似文献   

8.
振动光谱可以提供分子的振动信息,对于聚合物分子链的构象和链间的相互作用非常敏感。分子振动光谱成像作为一种原位无损检测技术,广泛应用于聚合物共混体系结晶、相态分布、界面扩散等性质的研究。本文综述了拉曼(Raman)光谱和红外(IR)光谱成像技术以及其衍生的具有高空间分辨率的红外-原子力联用技术(IR-AFM)、拉曼-原子力联用技术(Raman-AFM)以及针尖增强拉曼光谱技术(TERS)在聚合物共混体系研究中的最新应用进展,以探索并扩展振动光谱成像技术在高分子领域中的应用。  相似文献   

9.
本文采用密度泛函方法计算了液晶分子PCH7在太赫兹波段的动态极化率,采用B3LYP/6-311G(d)方法对PCH7分子进行几何结构优化,在优化构型基础上,采用M06-2x/6-311++G(2d,p)方法计算了体系分子在589nm和1.5THz时的含频极化率,通过极化率密度考察了尾链、核心结构和极性取代基等不同基团对极化率数值的贡献.  相似文献   

10.
近年来实验发现扭曲型分子内电荷转移(TICT)分子具有独特的分子内电荷转移机理和不同寻常的NLO响应系数.本文在MP2/6-311++G(d,p)水平上,结合有限场方法系统探讨了不同共轭链及共轭链长度对TICT分子一阶超极化率β的影响,并与传统D-π-A分子相比较.研究表明,共轭链对TICT分子与传统D-π-A分子β影响不同,且随着共轭链增长,TICT分子β提高更为显著.特别是共轭链为苯环的P4分子,当苯环重复单元数n=3时,其β远远大于其它具有不同共轭链的分子.  相似文献   

11.
紫外/臭氧改性法是一种操作简单、成本低廉的PDMS表面亲水改性方法。采用该方法对PDMS表面进行亲水改性,利用接触角测量仪对改性效果进行评价,并与PDMS无臭氧紫外法进行了比较。测试表明PDMS表面经紫外/臭氧法处理12小时后,表面接触角达到60°左右,在空气中放置两周后仍保持较好的亲水性。其改性机理可以通过多种表征手段进行分析。红外光谱测试可以看出,PDMS在经过紫外/臭氧改性后,其表面官能团变化明显,随改性时间延长,疏水基团—CH3逐渐减少,亲水基团Si—OH和—OH逐步增加,二氧化硅典型红外光谱峰也同时出现。通过扫描电镜和能谱测试可以看出,PDMS表面经过改性产生了二氧化硅为主的硅的氧化物。综合上述结果,紫外/臭氧处理法能够使PDMS表面亲水基团增多,同时生成类玻璃态SiO_x薄层,既改善了PDMS表面的亲水性,又阻止了PDMS表面疏水性的完全恢复,亲水性可以长时间保持。  相似文献   

12.
李明宇  薛懿  罗根  张超 《中国光学》2013,6(1):103-110
提出采用不可逆封合技术来解决可逆封合的平面光波导生物传感器的微流通道在注入液体压力较大时会出现漏液的问题。分别采用等离子体法、氧化法、紫外灯照射法和紫外胶法实现了聚二甲基硅氧烷(PDMS)和绝缘材料上的硅(SOI)波导的不可逆封合。首先,采用4种实验方案分别处理PDMS和SOI波导表面,测试了经上述几种方法处理后微流通道与波导的粘合能力的强弱。然后,定量分析PDMS和SOI波导的封合效果。最后,经过实验比较得出用等离子体处理PDMS和SOI波导表面得到的不可逆封合效果最好的结论。文中也讨论了其他实验因素对粘合程度的影响。  相似文献   

13.
In this study an atmospheric glow discharge with a fluorocarbon gas as precursor was used to modify the surface of polydimethyl siloxane (PDMS -[(CH3)2SiO]n-). The variation in protein immobilizing capability of PDMS was studied for different times of exposure. It was observed that the concentration of proteins adsorbed on the surface varied in an irregular manner with treatment time. The fluorination results in the formation of a thin film of fluorocarbon on the PDMS surface. The AFM and XPS data suggest that the film cracks due to stress and regains its uniformity thereafter. This Stranski-Krastanov growth model of the film was due to the high growth rate offered by atmospheric glow discharge.  相似文献   

14.
Design and preparation of frequency doubling antireflection coating with different thicknesses of interlayer were investigated for LiB3O5 (LBO) substrate. The design was based on the vector method. The thickness of the inserted SiO2 interlayer could be changed in a wide range for the four-layer design with two zeros at 1064 and 532 nm. The coatings without any interlayer and with 0.1 quarter-wave (λ/4), 0.3 λ/4, 0.5 λ/4 SiO2 interlayer were deposited respectively on LBO by using electron beam evaporation technique.All the prepared coatings with SiO2 interlayer indicated satisfying optical behavior. This expanded our option for the thickness of an interlayer when coating on LBO substrate. The prepared films with SiO2 interlayer showed better adhesion than that without any interlayer. The thickness of the interlayer affected the adhesion, the adhesion for the coating with 0.5 λ/4 SiO2 interlayer was not as good as the other two.  相似文献   

15.
《Applied Surface Science》2005,239(3-4):410-423
Silicone elastomers (Sylgard 184 and 170), based on poly(dimethylsiloxane) (PDMS), were surface treated by a combined exposure to UV and ozone. The effects of the treatments were analyzed as a function of time elapsed after stopping the treatments using different standard surface characterization techniques, such as water contact angle measurements, XPS and atomic force microscopy (AFM). However, the primary focus of this study was to apply the Johnson–Kendall–Roberts (JKR) contact mechanics approach to investigate PDMS samples prior to and following UV/ozone surface treatment. A gradual formation of a hydrophilic, silica-like surface layer with increasing modulus was observed with increasing UV/ozone exposure. A subsequent hydrophobic recovery after UV/ozone exposure was observed, as indicated by increasing contact angles. This supports the hypothesis that the hydrophobic recovery is mainly caused by the gradual coverage of a permanent silica-like structure with free siloxanes and/or reorientation of polar groups. PDMS containing a homogenously dispersed filler (Sylgard 184), exhibited a decreasing surface roughness (by AFM) when the oxidized surface region “collapsed” into a smooth SiOx layer (final surface roughness <2 nm). PDMS containing heterogeneously distributed, aggregated filler particles (Sylgard 170), exhibited an increasing surface roughness with treatment dose, which was attributed to the “collapse” of the oxidized surface region thus exposing the contours of the underlying filler aggregates (final surface roughness ∼140 nm). A dedicated device was designed and built to study the contact mechanics behavior of PDMS prior to, and following surface treatment. The value of the combined elastic modulus obtained for PDMS lens and semi-infinite flat surface system showed an increase in full agreement with the formation of a silica-like layer exhibiting a high elastic modulus (compared with untreated PDMS). The work of adhesion observed in JKR experiments exhibited an increasing trend as a function of treatment done in agreement with contact angle data. JKR experiments showed hydrophobic recovery behavior as anticipated from contact angle measurements. Single pull-off force measurements by JKR and numerical analysis of full-approach JKR curves were in quantitative agreement regarding practical work of adhesion values.  相似文献   

16.
在4H-SiC基底上设计并制备了Al2O3SiO2紫外双层减反射膜,通过扫描电镜(SEM)和实测反射率谱来验证理论设计的正确性.利用编程计算得到Al2O2和SiO2的最优物理膜厚分别为42.0 nm和96.1 nm以及参考波长λ=280 nm处最小反射率为0.09%.由误差分析可知,实际镀膜时保持双层膜厚度之和与理论值一致有利于降低膜系反射率.实验中应当准确控制SiO2折射率并使Al2O3折射率接近1.715.用电子束蒸发法在4H-SiC基底上淀积Al2O3SiO2双层膜,厚度分别为42 nm和96 nm.SEM截面图表明淀积的薄膜和基底间具有较强的附着力.实测反射率极小值为0.33%,对应λ=276 nm,与理论结果吻合较好.与传统SiO2单层膜相比,Al2O3SiO2双层膜具有反射率小,波长选择性好等优点,从而论证了其在4H-SiC基紫外光电器件减反射膜上具有较好的应用前景.  相似文献   

17.
Polydimethylsiloxane (PDMS)/fumed silica A-300 and PDMS/ZrO2/A-300 were studied using adsorption, thermogravimetry, temperature-programmed desorption (TPD) mass-spectrometry, infrared spectroscopy, XRD, and broadband dielectric relaxation spectroscopy. ZrO2 was synthesized on fumed silica with zirconium acetylacetonate in CCl4 at 350 K for 1 h and calcinated at 773 K for 1 h (1-4 reaction cycles). PDMS (5-40 wt.%) was adsorbed onto silica and zirconia/silica from hexane solution and then dried. Grafted zirconia changes the chemistry of the surface (because of its catalytic capability) and the topology of secondary particles (because of occupation of voids in aggregates of primary silica particles by zirconia nanoparticles) responsible for the textural porosity of the powders. Therefore, many properties (such as structural characteristics of the composites, reactions on heating in air and vacuum, interfacial relaxation phenomena, hydrophobicity as a function of treatment temperature, etc.) of PDMS/zirconia/silica strongly differ from those of PDMS/A-300. Broadening of the α-relaxation of PDMS at the interfaces of disperse oxides suggests both weakening of the PDMS-PDMS interaction and strengthening of the PDMS-oxide interaction.  相似文献   

18.
采用溶胶-凝胶工艺分别制备了SiO2和ZrO2单层薄膜、ZrO2/SiO2双层膜以及ZrO2/SiO2多层高反膜。用输出波长为1064nm、脉宽为6.3ns的YAG激光器对薄膜进行了激光损伤实验。观察了薄膜经强激光辐照后的损伤情况,讨论了薄膜的激光损伤行为,并从理论上分析了产生这些损伤的原因,为进一步镀制高质量的ZrO2/SiO2多层高反膜提供了依据。  相似文献   

19.
Back-surface diffusive reflectors have been widely applied in many optical systems to promote the efficiency used in system. In this work, we propose a novel way to fabricate a soft diffusive reflector by using of silicone (polydimethylsiloxane, PDMS). High-reflectance substrates were first fabricated by mixing nanoscaled TiO2 powders with PDMS polymers, and then microscale wave-like undulations were spontaneously developed after the substrates were dipped into H2SO4/HNO3 solutions. After optical examination, a TiO2/PDMS plate comprising microscale undulations, which can surely serve as a reflector, could reflect and diffuse light effectively. Besides, all fabrication processes can be executed in the ambient environment and at low temperature. This proposed method has a potential for mass production in the future.  相似文献   

20.
根据前期在相变储湿复合材料制备方面取得的成果,以SiO_2为载体材料、癸酸-棕榈酸为相变材料,采用溶胶-凝胶法制备癸酸-棕榈酸/SiO_2相变储湿复合材料。采用傅里叶红外光谱仪对癸酸-棕榈酸/SiO_2相变储湿复合材料制备过程各阶段的合成物质进行测试,即相变材料制备阶段、SiO_2载体材料制备阶段和癸酸-棕榈酸/SiO_2相变储湿复合材料制备阶段。研究SiO_2基相变储湿复合材料制备过程中SiO_2网络结构形成机理、癸酸-棕榈酸嵌入方式、癸酸-棕榈酸与SiO_2嵌合机理,阐明溶胶-凝胶法制备癸酸-棕榈酸/SiO_2相变储湿复合材料的相关机理。同时采用X射线衍射仪和扫描电子显微镜对癸酸-棕榈酸/SiO_2相变储湿复合材料的物质组成和微观形貌进行测试,以佐证癸酸-棕榈酸/SiO_2相变储湿复合材料的制备机理。结果表明:通过Si—O—Si基团断裂与重组形成大量闭合孔或笼有效地将癸酸-棕榈酸包覆,从而制备形成癸酸-棕榈酸/SiO_2相变储湿复合材料;在癸酸-棕榈酸/SiO_2相变储湿复合材料制备过程中癸酸-棕榈酸与SiO_2仅仅为物理嵌合,未发生任何化学反应;癸酸-棕榈酸/SiO_2相变储湿复合材料中SiO_2形成大量闭合孔或笼,一部分用于包覆癸酸-棕榈酸,发挥相变调温性能,另一部分利用其网络空隙结构,发挥储湿调湿性能,从而达到同时调节室内温度和湿度的目的。  相似文献   

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