搜索到3535篇“ DICHROISM“的相关文章
利用太赫兹圆二色性识别手性物质
2024年
不同手性的生物分子具有不同甚至相反的生物和药理活性。由于很多生物大分子的振动和转动能级分布在太赫兹波段,使得太赫兹波谱技术成为生物大分子识别的有效手段,但是太赫兹时域光谱系统都采用线偏振光源,无法对手性分子进行有效识别。我们在理论上利用线偏振的琼斯矩阵模型合成圆偏振下的琼斯矩阵,根据圆偏光的透射率差异性进一步计算样品的透射圆二色光谱,为表征不同手性分子提供了一种有效方法。基于透射式太赫兹时域光谱系统,对(R)-(-)-Ibuprofen和(S)-(+)-Ibuprofen的光谱进行测试,计算了(R)-(-)-Ibuprofen和(S)-(+)-Ibuprofen的线偏透过率和圆偏透过率;并计算出透射性圆二色光谱,两种手性物质的圆二色性值达到0.015,有效地实现了对(R)-(-)-Ibuprofen和(S)-(+)-Ibuprofen的识别效果。这一方法为利用太赫兹光谱技术检测和识别手性分子提供了参考。
纪旭洋孙爽张岩
关键词:琼斯矩阵圆二色性太赫兹手性识别
双层石墨烯手性超表面实现圆二色性及其动态调控研究
2024年
针对石墨烯手性超表面的研究主要集中在中红外波段,而在太赫兹波段的器件研究相对较少,以及石墨烯非本征结构产生的圆二色性不足的问题,根据石墨烯的特性设计了一种双层石墨烯手性超表面结构。该结构的上下两层石墨烯图案存在一定的夹角,通过调整这个夹角大小和中间层二氧化硅的厚度,研究了超表面结构的圆二色性。此外,还通过改变石墨烯的费米能级和弛豫时间,分析了超表面结构的动态调谐能力。仿真结果表明:该超表面结构能够在太赫兹频段实现圆二色性,并且具备动态调谐的能力。
宋效先张宇郭学文张海婷张晶晶戴子杰梁莹姚建铨
关键词:石墨烯太赫兹圆二色性费米能级弛豫时间
Linear dichroism transition and polarization-sensitive photodetector of quasi-one-dimensional palladium bromide
2024年
Perpendicular optical reversal of the linear dichroism transition has promising applications in polarization-sensitive optoelectronic devices. We perform a systematical study on the in-plane optical anisotropy of quasi-one-dimensional PdBr_(2) by using combined measurements of the angle-resolved polarized Raman spectroscopy(ARPRS) and anisotropic optical absorption spectrum. The analyses of ARPRS data validate the anisotropic Raman properties of the PdBr_(2) flake.And anisotropic optical absorption spectrum of PdBr_(2) nanoflake demonstrates distinct optical linear dichroism reversal. Photodetector constructed by PdBr_(2) nanowire exhibits high responsivity of 747 A·W^(-1) and specific detectivity of 5.8×10^(12) Jones. And the photodetector demonstrates prominent polarization-sensitive photoresponsivity under 405-nm light irradiation with large photocurrent anisotropy ratio of 1.56, which is superior to those of most of previously reported quasi-one-dimensional counterparts. Our study offers fundamental insights into the strong optical anisotropy exhibited by PdBr_(2), establishing it as a promising candidate for miniaturization and integration trends of polarization-related applications.
朱万里甄伟立牛瑞焦珂珂岳智来胡慧杰薛飞张昌锦
关键词:ANISOTROPY
手性分子构象分析装置圆二色光谱仪的加强与改造
2024年
圆二色光谱仪是对手性分子进行构象分析和理化性质表征的重要仪器.然而长期高强度的使用会产生光谱仪光学元件劣化、检测器灵敏度降低等问题.通过优化分光系统的光学元件提升光传输效率,升级具有更高量子效率的大面积雪崩硅光电二极管检测器,进而大幅提高仪器信噪比,同时将测量波长范围从175~900 nm扩展到175~1150 nm.在氙灯被点燃之前用氮气彻底净化仪器,把氧气排除在光谱仪之外是非常重要的操作步骤.安装具有监视、计划、流量设置、报警和辅助控制等功能的活性氮监测系统,可以实时监测控制仪器内部氮气吹扫情况.通过升级改造,既加强了仪器的性能,又节省了氮气消耗成本,同时仪器使用寿命将进一步延长.
孙爱君张云马宣
关键词:手性光学元件检测器
Ag(Ⅰ)与氯苯基苯并咪唑配合物的合成、圆二色性和荧光性质
2024年
本文合成了Ag(Ⅰ)与2-(o-氯苯基)苯并咪唑(OCBM)的配合物,采用元素分析、质谱、UV、IR、摩尔电导率等手段进行了表征。圆二色性研究发现,配合物在199nm处呈正科顿效应,而在208nm和247nm处呈负科顿效应。荧光性质研究表明,配合物的特征荧光发射峰出现在601nm和613nm处,荧光寿命τ601和τ613分别为0.40ns和0.35ns。Ag(Ⅰ)配合物可发射橙色荧光和红色荧光,是良好的荧光材料。
王卓渊林香凤
关键词:圆二色性荧光性质
Temperature-Induced Unfolding Pathway of Staphylococcal Enterotoxin B:Insights from Circular Dichroism and Molecular Dynamics Simulation
2024年
In this study,circular dichroism(CD)and molecular dynamics(MD)simulation were used to investigate the thermal unfolding pathway of staphylococcal enterotoxin B(SEB)at temperatures of 298–371 and 298–500 K,and the relationship between the experimental and simulation results were explored.Our computational findings on the secondary structure of SEB showed that at room temperature,the CD spectroscopic results were highly consistent with the MD results.Moreover,under heating conditions,the changing trends of helix,sheet and random coil obtained by CD spectral fitting were highly consistent with those obtained by MD.In order to gain a deeper understanding of the thermal stability mechanism of SEB,the MD trajectories were analyzed in terms of root mean square deviation(RMSD),secondary structure assignment(SSA),radius of gyration(R_(g)),free energy surfaces(FES),solvent-accessible surface area(SASA),hydrogen bonds and salt bridges.The results showed that at low heating temperature,domain Ⅰ without loops(omitting the mobile loop region)mainly relied on hydrophobic interaction to maintain its thermal stability,whereas the thermal stability of domain Ⅱ was mainly controlled by salt bridges and hydrogen bonds.Under high heating temperature conditions,the hydrophobic interactions in domain Ⅰ without loops were destroyed and the secondary structure was almost completely lost,while domain Ⅱ could still rely on salt bridges as molecular staples to barely maintain the stability of the secondary structure.These results help us to understand the thermodynamic and kinetic mechanisms that maintain the thermal stability of SEB at the molecular level,and provide a direction for establishing safer and more effective food sterilization processes.
LIU JiZHANG ShiyuZENG YuDENG Yi
An all-dielectric chiral metasurface with circular dichroism and asymmetric transmission characteristics
2024年
This paper designs an all-dielectric metasurface with tunable chiral properties in the near-infrared range,whose working wavelength is 1250—2200 nm.The metasurface exhibits circular dichroism(CD)and asymmetric transmission(AT)characteristics for circularly polarized light.The metasurface is a double-layer structure composed of Ge_2Sb_2Se_4Te_1(GSST).
WU QihangSHI ZhuolinHE JinglinDONG Jianfeng
关键词:CIRCULARDIELECTRICCHIRAL
基于准连续域束缚态的强圆二色性超表面
2024年
连续域束缚态最初是在量子力学中发现的,它是一种可保持局域化的波动现象.这种效应已在各种材料系统中得到广泛研究,包括压电材料、石墨烯和光子晶体.本工作提出了一种由中断的环形槽组成的四重旋转对称硅超表面.通过同时打破晶胞的面内反转对称性,实现了具有高品质因子和显著手性的准连续域束缚态.通过对动量空间中拓扑荷的研究,揭示了由超表面的内部共振机制产生的准连续域束缚态的独特拓扑特征.在合适的对称破坏下,具有平面内对称破坏的四重旋转对称超表面表现出–0.93的强圆二色性,并且其显示出了在对称破坏较大时的强圆二色性.这项工作所取得的成果在手性生物传感器和低阈值激光器等领域具有广阔的应用前景.
夏兆生刘宇行包正王丽华王丽华王刚吴博任信钢王刚
关键词:手性品质因子
Phonon dichroism in proximitized graphene
2023年
We systematically investigate the phonon dichroism in proximitized graphene with broken time-reversal symmetry.We find that in the absence of any type of spin–orbit coupling,phonon dichroism vanishes.Linear and circular phonon dichroism occur in the presence of uniform(staggered)intrinsic spin–orbit coupling and ferromagnetic(antiferromagnetic)exchange coupling.All these situations can be distinguished by their specific behaviors of phonon absorption at the transition point.Our finding provides new possibilities to use phonon dichroism to identify the form of spin–orbit coupling and exchange coupling in proximitized graphene on various magnetic substrates.
单文语
Enhanced Circular Dichroism of Z-Shaped Nanorod in Rectangular Nanohole Arrays
2023年
Chiral nanostructures have attracted much attention due to the valuable applications in biochemistry, medicine industries, and photonic devices. In this study, we propose an ease-of-fabrication planar nanostructure that consists of rectangular nanohole arrays in which the Z-shaped nanorod is arranged. Theoretically, such chiral nanostructure supports significant absorption circular dichroism (CD) compared with the Z-shaped nanorod because charge distributions are tuned after the introduction of the rectangular frame. Meanwhile, the Z-shaped nanorod directs the flow of current on the rectangular frame, thereby generating the effective quadruple electron oscillation in the Z-shaped nanorod. A novel mode also emerges when an identical Z-shaped nanorod is added into the rectangular hole. The studies will provide a novel approach to enhance the CD effect of planar structures. .
Ziye Zhang

相关作者

张其清
作品数:703被引量:994H指数:17
供职机构:新乡医学院
研究主题:增殖抑制 胶原 壳聚糖 发酵物 生物碱类化合物
盛中华
作品数:7被引量:15H指数:3
供职机构:上海市闵行区动物疾病预防控制中心
研究主题:上海白猪 提纯复壮 氟烷基因 多态性分析 位点
陈晖娟
作品数:3被引量:15H指数:1
供职机构:中国医学科学院北京协和医学院生物医学工程研究所天津市医用生物材料重点实验室
研究主题:胶原 细胞粘附 CMP 热稳定性 圆二色谱
王静洁
作品数:5被引量:18H指数:2
供职机构:中国医学科学院北京协和医学院生物医学工程研究所天津市医用生物材料重点实验室
研究主题:壳聚糖 纳米球 CMP 热稳定性 圆二色谱
熊青青
作品数:10被引量:29H指数:3
供职机构:中国医学科学院北京协和医学院生物医学工程研究所
研究主题:缓释载体 跨膜 内耳 自组装 牛血清白蛋白