期刊文献+
共找到8篇文章
< 1 >
每页显示 20 50 100
纳米线二聚体对单层WSe_(2)光致发光光谱的增强研究
1
作者 王慧 尤卿章 王培杰 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2023年第S01期297-298,共2页
二维过渡金属硫族化物(two-dimensional transition-metal dichalcogenides,2D-TMDs)是一种直接带隙半导体,表现出显著的光学特性,成为各种光电探测器、光伏和发光二级管等光电器件的理想材料。然而,由于原子级厚度的限制,TMDs的本征光... 二维过渡金属硫族化物(two-dimensional transition-metal dichalcogenides,2D-TMDs)是一种直接带隙半导体,表现出显著的光学特性,成为各种光电探测器、光伏和发光二级管等光电器件的理想材料。然而,由于原子级厚度的限制,TMDs的本征光吸收率和发射率非常低,限制了光与物质之间的相互作用,严重阻碍了其在电子学和光子学中的应用。而等离子体纳米结构可以将光限制在纳米尺度,极大增强局域电场强度,从而显著增强光与物质之间的相互作用。因此在这里,构建了由单层WSe_(2)和银纳米线二聚体(nanowire dimer,NWD)组成的复合体系,研究了单层WSe_(2)激子与NWD等离子体的相互作用,相比于原始单层WSe_(2),在NWD/WSe_(2)复合体系中荧光强度初步实现了1.2倍增强。理论模拟揭示这里荧光增强源于NWD的高辐射效率、purcell效应和激发增强,理论分析很好的解释了实验结果,证明了该体系可以有效地增强单层WSe_(2)的荧光。 展开更多
关键词 单层硒化钨 纳米线 光致发光光谱 光与物质相互作用
下载PDF
单极射频与聚对二甲基羟己酮线植入对猪动物模型皮肤组织病理变化的影响 被引量:1
2
作者 张晓 李凯 +2 位作者 屈欢欢 王莉 高琳 《中国皮肤性病学杂志》 CAS CSCD 北大核心 2023年第9期1003-1007,1015,共6页
目的研究在猪动物模型中单极射频(MRF)与聚对二甲基羟己酮(PDO)线植入治疗后皮肤的病理变化。方法在两只幼猪腹部皮肤行MRF和PDO线植入,于MRF和PDO线植入后1个月、3个月进行皮肤活检及组织病理学检查。结果在两个治疗组中,与基线水平相... 目的研究在猪动物模型中单极射频(MRF)与聚对二甲基羟己酮(PDO)线植入治疗后皮肤的病理变化。方法在两只幼猪腹部皮肤行MRF和PDO线植入,于MRF和PDO线植入后1个月、3个月进行皮肤活检及组织病理学检查。结果在两个治疗组中,与基线水平相比,真皮胶原束的厚度在治疗后1个月、3个月均显著增加(P<0.05),MRF组真皮胶原重塑较PDO线组多。MRF治疗后1个月,皮下脂肪小叶有轻度破坏,3个月时明显好转。PDO线植入后1个月皮下脂肪层出现两个圆形空洞,周围可见胶原纤维包裹,炎症细胞浸润明显,血管增多;3个月时,皮下脂肪层纤维间隔增宽。结论MRF和PDO线植入引起皮肤组织一系列变化,两者均可诱导胶原重塑,MRF对真皮胶原重塑作用优于PDO线植入。MRF治疗后出现轻度皮下脂肪小叶破坏,PDO线植入后导致皮下脂肪层植入线周围胶原纤维和血管环境改变。 展开更多
关键词 猪动物模型 单极射频 甲基羟己酮线 皮肤组织病理
下载PDF
4-甲基-1-戊烯的合成技术 被引量:4
3
作者 秦旭东 王燕 +1 位作者 宋洪强 李正西 《精细化工原料及中间体》 2007年第5期39-41,43,共4页
4-甲基-1-戊烯(4MP1)作为共聚单体,可生产出性能优良的线型低密度聚乙烯LLDPE树脂。本文叙述了国外几种合成4MP1的技术路线,选择优化适合我国的生产方法,即丙烯在碱金属催化剂的作用下二聚生成4MP1,反应温度120-170℃,反应压力45.4-181.... 4-甲基-1-戊烯(4MP1)作为共聚单体,可生产出性能优良的线型低密度聚乙烯LLDPE树脂。本文叙述了国外几种合成4MP1的技术路线,选择优化适合我国的生产方法,即丙烯在碱金属催化剂的作用下二聚生成4MP1,反应温度120-170℃,反应压力45.4-181.4MPa,反应过程的4MP1选择性大于80%,4MP1/4MP2大于20。 展开更多
关键词 4-甲基-1-戊烯 丙烯 二聚线 型低密度乙烯
下载PDF
V(f,z)分析方法在小尺寸材料弹性常数测量中的应用 被引量:2
4
作者 龚裕 谭博涛 +2 位作者 宋国荣 吕炎 何存富 《北京工业大学学报》 EI CAS CSCD 北大核心 2012年第9期1298-1301,共4页
针对小尺寸材料弹性常数的测量,提出了一种频域处理方法——V(f,z)分析方法.V(f,z)分析方法基于声学显微镜技术,使用线聚焦聚偏二氟乙烯(PVDF)探头,测定材料的表面波波速,计算材料的弹性常数.采用该分析方法对块体不锈钢试件的弹性常数... 针对小尺寸材料弹性常数的测量,提出了一种频域处理方法——V(f,z)分析方法.V(f,z)分析方法基于声学显微镜技术,使用线聚焦聚偏二氟乙烯(PVDF)探头,测定材料的表面波波速,计算材料的弹性常数.采用该分析方法对块体不锈钢试件的弹性常数进行了测量,测量结果与理论值相吻合.误差分析结果表明,V(f,z)分析方法具有较高的测量精度,泊松比和杨氏模量的测量误差均小于5%,能满足工程和科学研究的要求.此外,V(f,z)分析方法可测得不同频率的频散曲线,不仅适用于块体材料,而且适用于薄板、涂层等具有频散特性的材料,这为进一步测量薄板材料和涂层材料的弹性常数奠定了分析基础. 展开更多
关键词 V(f z)分析方法 弹性常数 线氟乙烯探头 小尺寸材料
下载PDF
Preparation and Characterization of Solid Dispersions of Silymarin with Polyethylene Glycol 6000 被引量:6
5
作者 李凤前 胡晋红 姜远英 《Journal of Chinese Pharmaceutical Sciences》 CAS 2003年第2期76-81,共6页
Aim To prepare and characterize solid dispersions of silymarin with the intention of improving their dissolution properties. Methods The solid dispersions were prepared by the fusion method with polyethylene glycol ... Aim To prepare and characterize solid dispersions of silymarin with the intention of improving their dissolution properties. Methods The solid dispersions were prepared by the fusion method with polyethylene glycol 6000(PEG 6000) as the carrier. Evaluation of the properties of the dispersions was performed using dissolution studies, X ray powder diffraction and Fourier transform infrared (FT IR) spectroscopy. Results The rate of dissolution of silymarin was considerably improved as compared with pure silymarin when formulated in solid dispersions with PEG 6000. The data of the X ray diffraction showed some changes in the parameters of lattice spacing [ d ], peak position and relative intensities. FT IR together with those from X ray diffraction showed the absence of well defined drug polymer interactions. Conclusion The dissolution improvement of poorly soluble silymarin could be illuminated by the changes of the lattice parameters of PEG 6000 and the drug. 展开更多
关键词 SILYMARIN solid dispersions X ray powder diffraction FT IR spectroscopy DISSOLUTION PEG 6000
下载PDF
UV-Polarizing Linear Polyyne Molecules Aligned in PVA
6
作者 R. Sata H. Suzuki +3 位作者 N. Ueno Y. Morisawa M. Hatanaka T. Wakabayashi 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2019年第2期175-181,I0002,共8页
Electronic absorption bands of conjugated linear carbon chain molecules, namely polyynes H(C≡C)nH (n=5-7), are exploited to devise light-polarizing films applicable to the UV. Laser ablated polyynes are separated in ... Electronic absorption bands of conjugated linear carbon chain molecules, namely polyynes H(C≡C)nH (n=5-7), are exploited to devise light-polarizing films applicable to the UV. Laser ablated polyynes are separated in size and dispersed in a film of polyvinyl alcohol (PVA), which is stretched to align the trapped linear polyyne molecules inside. As a nature of the structural anisotropy, transition dipole of the UV absorption for polyyne molecules is in parallel with the molecular axis and the absorption occurs only for the electromagnetic wave having the amplitude of its electric vector along the molecular axis. Aligned and fixed orientationally in the solid PVA film, polyyne molecules act as selective absorbers of one of the polarization components of incident light at particular wavelength. Using a light source of linearly polarized UV light, whose direction of polarization is rotatable, angular dependence of the absorption intensity is investigated for the stretched PVA film containing aligned polyyne molecules and analyzed in terms of an order parameter in the theory of linear dichroism. 展开更多
关键词 Polyyne UV absorption Polyvinyl alcohol Linear dichroism Linearly polarized light POLARIZER
下载PDF
Molecular Dynamics Insights into Electron-Catalyzed Dissociation Repair of Cyclobutane Pyrimidine Dimer
7
作者 Liang Gao Yuxiang Bu 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2021年第6期850-860,I0004,共12页
Excess electrons are not only an important source of radiation damage,but also participate in the repair process of radiation damage such as cyclobutane pyrimidine dimer(CPD).Using ab initio molecular dynamics(AIMD)si... Excess electrons are not only an important source of radiation damage,but also participate in the repair process of radiation damage such as cyclobutane pyrimidine dimer(CPD).Using ab initio molecular dynamics(AIMD)simulations,we reproduce the single excess electron stepwise catalytic CPD dissociation process in detail with an emphasis on the energy levels and molecular structure details associated with excess electrons.On the basis of the AIMD simulations on the CPD aqueous solution with two vertically added excess electrons,we exclude the early-proposed[2+2]-like concerted synchronous dissociation mechanism,and analyze the difference between the symmetry of the actual reaction and the symmetry of the frontier molecular orbitals which deeply impact the mechanism.Importantly,we propose a new model of the stepwise electron-catalyzed dissociation mechanism that conforms to the reality.This work not only provides dynamics insights into the excess electron catalyzed dissociation mechanism,but also reveals different roles of two excess electrons in two bond-cleavage steps(promoting versus inhibiting). 展开更多
关键词 Excess electron Cyclobutane pyrimidine dimer Electron catalysis Frontier orbital analysis Ab initio molecular dynamics simulation
下载PDF
Tetraphenylethylene-BODIPY aggregation-induced emission luminogens for near-infrared polymer light-emitting diodes 被引量:9
8
作者 Sebnem Baysec Alessandro Minotto +5 位作者 Patrick Klein Simone Poddi Andrea Zampetti Sybille Allard Franco Cacialli Ullrich Scherf 《Science China Chemistry》 SCIE EI CAS CSCD 2018年第8期932-939,共8页
The aggregation-induced emission(AIE) phenomenon provides a new direction for the development of organic light-emitting devices. Here, we present a new class of emitters based on 4,4-difluoro-4-bora-3 a,4 a-diaza-s-in... The aggregation-induced emission(AIE) phenomenon provides a new direction for the development of organic light-emitting devices. Here, we present a new class of emitters based on 4,4-difluoro-4-bora-3 a,4 a-diaza-s-indacene(BODIPY), functionalized at different positions with tetraphenylethylene(TPE), which is one of the most famous AIE luminogens. Thanks to this modification, we were able to tune the photoluminescence of the BODIPY moiety from the green to the near-infrared(NIR)spectral range and achieve PL efficiencies of ~50% in the solid state. Remarkably, we observed an enhancement of the AIE and up to ~100% photoluminescence efficiencies by blending the TPE-substituted BODIPY fluorophores with a poly[(9,9-di-noctylfluorene-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4,7-diyl)](F8 BT) matrix. By incorporating these blends in organic lightemitting diodes(OLEDs), we obtained electroluminescence peaked in the range 650–700 nm with up to 1.8% external quantum efficiency and ~2 m W/cm2 radiance, a remarkable result for red/NIR emitting and solution-processed OLEDs. 展开更多
关键词 BODIPY organic light-emitting diode aggregation-induced emission NIR emission photoluminescence electro LUMINESCENCE
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部