检索结果-南通市图书馆

第一届全国光功能材料青年学者研讨会2018

作者： Chensheng Ma wai-ming kwok Chi-ming Che College of Chemistry and Environmental Engineering Shenzhen University Department of Applied Biology and Chemical Technology The Hong Kong Polytechnic UniversityHung Hom Department of Chemistry The University of Hong Kong

Photo-luminescent organic metal complexes have found diverse applications in areas such as sensor materials,OLEDs, and photo-catalysis, etc. To understand at molecular level the excited state dynamics of metal complex and how this may vary with the metal center, the ligand structure, and environmental factor is essential for rational design and better performance of metal complexes in the various applications. Herein we demonstrate utilization of a range of complementary ultrafast spectroscopy to investigate in real time the excited state dynamics for series of recently synthesized mono-, bi, and multi-nuclear transition metal complexes both in the solid state and in solution with solvent of varied properties. By direct probe of the excited state spectra and temporal evolution of the spectra, we are able to unravel the elementary steps underlying the entire dynamics of the excited state deactivation;the results unveil a number of remarkable features crucial for elucidating several key processes of photo-excited metal complexes. This involves the rate and timescale of the intersystem crossing,1-3 the molecular mechanism to delayed fluorescence for the multiple emission phenomenon,2,3 and the rapid events dictated by phase condition and solvent property for luminescence and photochemical outcomes of a prototype bi-nuclear gold complex.4 We also present result of time-resolved study on a tridentated Pt（II）complex exhibiting luminescence with energy and intensity highly sensitive to conformation of nucleic acids arising due to sequence specific intercalation binding interaction between the complex and the nucleic acids.5 Our work enriches knowledge on photo-physics and photochemistry of metal complexes, providing significant insights into the structure-property relationship for this important class of molecules.

关键词： luminescent metal complex,ultrafast spectroscopy excited state dynamics,dual emission DNA intercalation

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Time-Resolved Spectroscopy Studies of P-Hydroxyphenacyl Caged Phototrigger Compounds

Time-Resolved Spectroscopy Studies of P-Hydroxyphenacyl Cage...

引用

第九届全国化学动力学会议

作者： David Lee Phillips wai ming kwok Wing Sum Chan Department of Chemistry The University of Hong KongPokfulam Road Hong Kong S.A.R.P.R.China Department of Chemistry The University of Hong KongPokfulam RoadHong Kong S.A.R.P.R.China Department of Chemistry The University of Hong KongPokfulam Road Hong Kong S.A.R.P.R.China

＜正＞The need for fast and localized release of biological stimulants for real-time monitoring of physiological responses in biological systems has driven the search for efficient phototrigger compounds. The p-hydroxyphenacyl （pHP） caged class of phototrigger compounds was found to have a favorable photodeprotection reaction in

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Ultrafast time-resolved study of model DNAs and binding interactions between DNA and metal complex

Ultrafast time-resolved study of model DNAs and binding inte...

引用

中国化学会第30届学术年会-第四十四分会：化学动力学

作者： Chensheng Ma wai-ming kwok David.L.Phillips Chi-ming Che College of Chemistry and Environmental Engineering Shenzhen University Department of Applied Biology and Chemical Technology The Hong Kong Polytechnic University Department of Chemistry The University of Hong Kong

Study of the excited states of nucleic acids has been undergoing a revival in recent years impelled largely by femtosecond time-resolved spectroscopy. The properties and dynamics of nucleic acid excited states play a pivotal role in controlling both the photostability and the propensity towards photodamage of the genetic material, which is crucial for understanding evolution of life and is also essential for public health. Binding interactions between nucleic acids and metal complex have on the other hand found broad applications in areas such as develop of anticancer drug and sensory material, etc. In this presentation, we will demonstrate ultrafast spectroscopic study which we integrated fs broadband time-resolved fluorescence with fs transient absorption to characterize directly excited states of A/T model DNAs as well as to explore bindings between an platinum complex with a series of selected model and natural DNAs and RNAs. The results we obtained for A/T DNAs show that the electronic nature, energy, and decay dynamics of excited states all vary significantly with the composition, sequence, and conformation of the oligomeric *** bindings between platinum complex and nucleic acids, manifested by the energy and lifetime of emission from the interacting systems, exhibit critical dependence on the content and sequence of the nucleic acids. In particular, it was found that the intercalation of the complex into A/T containing DNAs may give rise to a highly emissive adduct with abnormally low emission energy and unusually long emission lifetime rarely reported in the literature. These findings provide important insights for in-depth understanding of the nucleic acid excited states and binding interactions of metal complex with nucleic acids, which may have important ramification for improving the applications in related areas.

关键词： DNA excited states time-resolved fluorescence transient absorption metal complex DNA binding

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Three-Photon Up-conversion from Polymeric Lanthanide (III) Complexes

Three-Photon Up-conversion from Polymeric Lanthanide (III) C...

引用

第五届全国稀土发光材料学术研讨会

作者： Ka-Leung Wong wai-ming kwok Wing-Tak Wong David Lee Phillips Kok-wai Cheah Department of Chemistry The University of Hong Kong Pokfulam Road Hong Kong P. R.China Department of Physics Hong Kong Baptist University Kowloon Tong Hong Kong P. R.China

We report the first observation of three-photon up-conversion emission from polymeric organic lanthanide complexes, [N,N’,N”-tris(2–methoxybenzamido)-triethylamine]-lanthanide complexes (Ln = Tb, Eu),

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Time-resolved Rresonance Raman Study of Hydroxyphenacyl Compounds

Time-resolved Rresonance Raman Study of Hydroxyphenacyl Comp...

引用

第十三届全国光散射学术会议

作者： David Lee Phillips Chensheng Ma wai ming kwok Wing Sum Chan Peng Zou The University of Hong Kong Department of Chemistry The University of Hong Kong

＜正＞Real-time monitoring of physiological responses in biological systems needs compounds called phototriggers that release the biological stimulant in a very fast and localized *** need for the fast and localized release of biological stimulants has driven the design and development of efficient phototngger *** p-hydroxyphenacyl（pHP）caged class of phototriggers was recently observed to undergo a

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Combined femtosecond time-resolved fluorescence and transient absorption study of excited state dynamics of cytosine and derivatives

Combined femtosecond time-resolved fluorescence and transien...

引用

第十五届全国化学动力学会议

作者：马晨生 C.T.-L.Chan C.C.-W.Cheng wai-ming kwok School of Chemistry and Environmental Engineering Shenzhen University Department of Applied Biology and Chemical Technology The Hong Kong Polytechnic University

Nucleobases, the building blocks and also the chromophores of the genetic materials, have been extensively studied both experimentally and theoretically. The ultra-short lifetime of electronically excited states of the bases formed after absorption of UV light has been considered the key factor for the vitally important photo-stability of the bases to protect against UV irradiation. However, due to the complex nature of the excited states, in particular the likely involvement of various dark natured states that are sensitive both to covalent modification and environmental condition, the precise timescale and elementary steps underlying the nonradiative process causing the very short excited state lifetime are not fully understood. Here we present ultrafast time-resolved study which we coupled femtosecond broadband time-resolved fluorescence with transient absorption to directly probe and monitor temporal evolution of UV-excited nucleobases[1-4] with an emphasize on cytosine and a range of its derivatives in solvents of different properties.[1] The results we obtained uncover remarkable roles of the solvents and the substitutions in altering significantly the lifetime of excited states as well as to control the participation or not of dark natured state during the course of excited state deactivation. Our study provides direct evidences and new insights for a clearer picture describing the mechanism of nonradiative dynamics of cytosine and derivatives.

关键词： Nucleobase excited state nonradiative dynamics ultrafast time-resolved fluorescence fs transient absorption

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Ferroptosis and glaucoma: implications in retinal ganglion cell damage and optic nerve survival

引用

Neural Regeneration Research 2023年第3期18卷 545-546页

作者： ming Yang kwok-Fai So wai-Ching Lam Amy Cheuk Yin Lo Department of Ophthalmology School of Clinical MedicineLi Ka Shing Faculty of MedicineThe University of Hong KongHong Kong Special Administrative RegionChina State Key Laboratory of Brain and Cognitive Sciences The University of Hong KongHong Kong Special Administrative RegionChina GHM Institute of CNS Regeneration Jinan UniversityGuangzhouGuangdong ProvinceChina

Glaucoma and visual pathway degeneration:Glaucoma is the leading cause of irreversible blindness worldwide,which leads to a progressive loss of *** can be classified into two types:primary open-angle glaucoma and primary closed-angle *** open-angle glaucoma can be caused by the blockage of the trabecular meshwork,and this results in elevation of the intraocular pressure(IOP),leading to retinal ganglion cell(RGC)***,many glaucoma patients have normal IOP;this is known as normal-tension ***,excitotoxic damage and oxidative stress can also lead to RGC damage in normal-tension glaucoma(Almasieh et al.,2012).Glaucomatous genes such as TIGR,OPTN,and CYP1B1 have been suggested to contribute to the pathogenesis of ***,some glaucomatous patients may remain asymptomatic in the early,moderate,and late *** type of glaucoma is primary closed-angle *** this clinical condition,a relative pupillary block is contributed by the iris obstructing aqueous *** patients may suffer from corneal swelling,headache,nausea,and blurred vision during the acute phase.

关键词： glaucoma damage degeneration

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Spatial memory enhances the evacuation efficiency of virtual pedestrians under poor visibility condition

引用

Chinese Physics B 2018年第3期27卷 560-567页

作者： Yi Ma Eric wai ming Lee Meng Shi Richard kwok Kit Yuen Institute for Disaster Management and Reconstruction Sichuan University Chengdu 610207 China Department of Architecture and Civil Engineering City University of Hong Kong Kowloon Hong Kong China

Spatial memory is a critical navigation support tool for disoriented evacuees during evacuation under adverse environ-mental conditions such as dark or smoky conditions. Owing to the complexity of memory, it is challenging to understand the effect of spatial memory on pedestrian evacuation quantitatively. In this study, we propose a simple method to quan- titatively represent the evacuee＇s spatial memory about the emergency exit, model the evacuation of pedestrians under the guidance of the spatial memory, and investigate the effect of the evacuee＇s spatial memory on the evacuation from theoretical and physical perspectives. The result shows that （i） a good memory can significantly assist the evacuation of pedestrians under poor visibility conditions, and the evacuation can always succeed when the degree of the memory exceeds a threshold （φ〉 0.5）; （ii） the effect of memory is superior to that of ＂follow-the-crowd＂ under the same environmental conditions; （iii） in the case of multiple exits, the difference in the degree of the memory between evacuees has a significant effect （the greater the difference, the faster the evacuation） for the evacuation under poor visibility conditions. Our study provides a new quantitative insight into the effect of spatial memory on crowd evacuation under poor visibility conditions.

关键词： crowd evacuation memory visibility social force model

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Characterizing the Urban Temperature Trend Using Seasonal Unit Root Analysis:Hong Kong from 1970 to 2015

引用

Advances in Atmospheric Sciences 2016年第12期33卷 1376-1385页

作者： wai-ming TO Tat-wai YU Macao Polytechnic Institute Rua de Luis Gonzaga GomesMacao SARChina

This paper explores urban temperature in Hong Kong using long-term time series. In particular, the characterization of the urban temperature trend was investigated using the seasonal unit root analysis of monthly mean air temperature data over the period January 1970 to December 2013. The seasonal unit root test makes it possible to determine the stochastic trend of monthly temperatures using an autoregressive model. The test results showed that mean air temperature has increased by 0.169~ C （10 yr） - 1 over the past four decades. The model of monthly temperature obtained from the seasonal unit root analysis was able to explain 95.9% of the variance in the measured monthly data -- much higher than the variance explained by the ordinary least-squares model using annual mean air temperature data and other studies alike. The model accurately predicted monthly mean air temperatures between January 2014 and December 2015 with a root-mean-square percentage error of 4.2%. The correlation between the predicted and the measured monthly mean air temperatures was 0.989. By analyzing the monthly air temperatures recorded at an urban site and a rural site, it was found that the urban heat island effect led to the urban site being on average 0.865~C warmer than the rural site over the past two decades. Besides, the results of correlation analysis showed that the increase in annual mean air temperature was significantly associated with the increase in population, gross domestic product, urban land use, and energy use, with the R2 values ranging from 0.37 to 0.43.

关键词： urban temperature trend urban heat island effect seasonal unit root tests long-term time series

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The prediction of exit choice using cumulative prospect value

引用

Journal of Safety Science and Resilience 2023年第1期4卷 20-25页

作者： Dongli Gao Wei Xie Ruifeng Cao Eric wai ming Lee Richard kwok Kit Yuen Jingwen Weng Department of Architecture and Civil Engineering City University of Hong KongHong KongChina State Key Laboratory of Fire Science University of Science and Technology of ChinaHefei230026China

Exit choice is essential for pedestrian safety and evacuation efficiency during the context of an emergency. Cumulative prospect theory is a widespread realistic decision-making theory that can transform choice outcomes and probabilities into subjective terms and integrate them as a parameter of cumulative prospect value (CPV), which determines the decision. The main contribution of this paper is the use of the CPV to predict exit choice. Furthermore, the different decision-making rules including Max, exponential(Expo), and Ratio (i.e., the three variable choice functions) were summarized and examined. This study used a confusion matrix to compare the predicted results with experimental data. Consequently, the parameters of Accuracy and F1-score showed that the predictions from Max and Expo were significantly more realistic while the results from Ratio were much more robust.

关键词： Decision-making behavior Exit choice Evacuation model Cumulative prospect value

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：