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| 1 | Temperature modulation of concentration quenching in lanthanide-doped nanoparticles for enhanced upconversion luminescence显示文摘lanthanide 离子的做的集中为操作 upconversion nanoparticles (UCNP ) 的光性质是重要的。然而,在高度做的 UCNP 熄灭的严肃的集中为进一步提高的 upconversion 光(UCL ) 仍然是重要限制。此处,我们在熄灭的集中上检验了温度的效果稀土元素的 UCNP,被俯看的一个问题,和我们证明它为 UCNP 的生物医学或光的应用是重要的。在这个工作,我们由做准备了一系列 UCNP 嗯 3+ 在在一个 NaLuF 4:Yb3+ 矩阵的不同集中的光中心。在房间温度(298 K ) ,不变的光致发光(PL ) 光谱学显示出与增加做集中 Er 3+ 排放熄灭的实质的集中。然而,熄灭效果的集中在更低的温度不再是有效的。进一步从解决时间的 PL 光谱学获得的运动曲线证明熄灭动力学的集中极其在低温实验法的温度区域被改变,即,在 160 K 下面。我们熄灭机制的温度可切换的集中上的工作可以使改善 UCL 性质清楚些,支持他们的实际应用。 | Luoyuan Li Ningjiu Zhao Limin Fu Jing Zhou Xicheng Ai Jianping Zhang | 2018 | Nano Research2018，11，4： | 3 |
| 2 | Mechanism of intram olecular charge transfer in DNA helix as probed by the use of the fluorescent 2-aminopurine显示文摘As a structural analogue of adenine, 2-aminopurine (2Ap) is often used as a fluorescent probe to study the intramolecular charge transfer reaction in DNA. We have designed and synthesized a series of model DNA helix with the variation in the distance between the 2Ap probe and the GGG sequence, and have investigated, by means of picosecond time-resolved fluorescence spectroscopy, the effect of the length of the bridge (consisting of a number of inosines, I) separating the electron donor (???GGG???) and the acceptor (2Ap) on the charge transfer dynamics. The fluorescence dynamics of 2Ap exhibited three exponential decay components, the one with a time constant of a few hundred picoseconds is assigned to the intramolecular charge transfer from GGG to 2Ap. Within 2.4 nm of the donor-acceptor separation, the rate of charge transfer decreased exponentially upon increasing the separation, from which the decay factor β is determined to be 1.3 nrrf-1. Beyond 2.4 nm, however, the rate started toincrease, this abnormal behavior of charge transfer is interpreted in terms of the match of elec- tronic energies between the l-bridge and the donor/acceptor couple. | ZHANG Huijuan WANG Peng WANG Xuefei FENG Juan XU Sichuan AI Xicheng ZHANG Xingkang ZHANG Jianping | 2004 | Science China Chemistry2004，47，5： | 3 |
| 3 | Femtosecond optical Kerr effect of PbS nanoparticles modification effect显示文摘 | Lin Guo Xicheng Ai | 2000 | Materials Chemistry and Physics2000，63，： | 1 |
| 4 | Characterization of refractive index distribution of polymer optical fiber显示文摘A focusing method is developed to characterize the refractive index profile of polymer optical fiber (POF). Based on the refractive index profile the theoretical bandwidth and the core index exponent a (a > 0) of POF are calculated. The results show that the value of theoretical bandwidth agrees well with the experimental data. | DAI Xinhua AI Xicheng LIU Zhimin YANG Mingjun YANG Guangying HAN Buxing XU Jian ZHANG Xianmin WU Xin | 2002 | Chinese Science Bulletin2002，47，12： | 1 |
| 5 | Interactions between meso-tetrakis(4-(N-methylpyridiumyl))porphyrin TMPyP4 and DNA G-quadruplex of telomeric repeated sequence TTAGGG显示文摘The binding properties between meso-tetrakis(4-(N-methylpyridiumyl))porphyrin (TMPyP4) and the parallel DNA G-quadruplex (G4) of telomeric repeated sequence 5′-TTAGGG-3′ have been characterized by means of circular dichroism,steady-state absorption,steady-state fluorescence and picosecond time-resolved fluorescence spectroscopies. The binding constant and the saturated binding number were determined as 1.29×106 (mol/L)-1 and 3,respectively,according to steady-state absorption spec-troscopy. Based on the findings by the use of time-resolved fluorescence spectroscopic technique,it is deduced that TMPyP4 binds to a DNA G-quadruplex with both the thread-intercalating and end-stacking modes and at the saturated binding state,one TMPyP4 molecule intercalates into the intervals of G-tetrads while the other two stack to the ends of the DNA G-quadruplex. | ZHANG HuiJuan WANG XueFei WANG Peng PANG SiPing AI XiCheng ZHANG JianPing | 2008 | Science China Chemistry2008，51，5： | 1 |
| 6 | Ultrafast isomerization dynamics of retinal in bacteriorhodopsin as revealed by femtosecond absorption spectroscopy显示文摘A femtosecond (fs) broad-band absorption apparatus was used to measure the early photoisomeriza-tion process of bacteriorhodopsin’s (BR) photocycle to reveal the character of the important interme-diate of J625 and to obtain a deeper understanding of the role of photoisomerization in BR photocycle. Two time constants of 0.5 ps (95%) and 2.0 ps (5%) were brought out by global fitting on thirty curves in the near-infrared region. We suggest that the first time constant results from the decay of I460 interme-diate,and the longer component might be associated with BR isomer. The global analysis over 450,540,630,710 and 870 nm traces identified two time constants,~0.5 and~3 ps. The slower component can be extracted from the processes of both J625→BR568 (540 nm) and J625→K590 (630 nm),suggesting J-in-termediate takes a partial cis configuration. The obvious negative feature in early delay time of 700―780 nm regions was attributed to the radiative transition (stimulated emission) from the Franck-Condon active configuration along the isomerization potential surface of all-trans-retinal. | WU YiShi ZHONG Sheng AI XiCheng HU KunSheng ZHANG JianPing | 2008 | Chinese Science Bulletin2008，53，13： | 0 |
| 7 | Spectroscopic study on the photophysical properties of chlorine substituted tetraphenylporphyrin-histidine and its zinc(Ⅱ)complexes显示文摘The photophysical properties of ortho-Cl, meta-Cl and para-Cl substituted tetraphenylporphy-rin-histidine and their zinc (Ⅱ) complexes have been studied by means of steady-state absorption and fluo-rescence spectroscopies, as well as time-resolved fluo-rescence spectroscopy. For the cases of both free-base and zinc complexes, it was found that the or-tho-chlorine substitution onto the phenyl rings signifi-cantly altered the fluorescence quantum yield, the fluorescence lifetime and the ratio between radiative and nonradiative deactivation rates of the porphyrin chromophore, i.e. the photophysical parameters werequite different from those of meta- and para-substi-tuted compounds. On the other hand, however, theintroduction of covalently-linked histidine did not ex-ert much effects on the photophysical behavior of the porphyrin chromophore. The results are interpreted in terms of the steric effect and the heavy-atom effect from the chlorine atoms substituted onto the phenylrings. | ZHANG Huijuan, FENG Juan, AI Xicheng, ZHANG Xingkang, YU Zhongheng & ZHANG Jianping State Key Laboratory for Structural Chemistry of Unstable and StableSpecies Center of Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China | 2003 | Chinese Science Bulletin2003，48，17： | 0 |
| 8 | Influence of nanostructure on the device performance and charge recombination dynamics of P3HT:PCBM solar cells显示文摘In this paper,we investigated the recombination dynamics of photogenerated charge carriers in a poly(3-hexylthiophene)(P3HT):[6,6]-phenyl-C 61-butyric acid methyl ester(PC 61 BM) blend system with donor-acceptor ratio of 1:1 before and after solvent annealing treatment.The technique of transient photocurrent and photovoltage measurements were used,and charge carriers were photogenerated by a 7 ns laser pulse at room temperature(298 K).In transient photocurrent measurement,we observed some differences in the saturation extracted charge in P3HT:PCBM solar cells with different power efficiencies.In addition,the bimolecular recombination coefficient is found to be 3.5×10-13 cm 3 s-1 for annealed devices,while 9.5×10-12 cm3 s-1 for as-cast devices.In the transient photovoltage measurement,we found that the photovoltage decay can be fitted by power-law equation at long time scale.The exponent parameter is 2.6 for annealed devices,which can be described as trap-free bimolecular recombination;is 1.76 for as-cast device due to the trap-limited bimolecular recombination.These experimental results indicate that the nanomorphology of active layer indeed have influence on charge carriers dynamics in P3HT:PCBM blend systems. | LI Dan XING YaDong YUE He ZHANG JianPing AI XiCheng | 2012 | Chinese Science Bulletin2012，57，26： | 0 |
| 9 | Trans-membrane controlling of an amphiphilic metalloporphyrin显示文摘In order to perform a transfer process of the porphyrin moiety across membrane media, an amphiphilic porphyrin 5,10,15-tri(4-hydroxyphenyl)-20-(4-hexadecyloxy-phenyl) porphyrin (P1) and its metalloporphyrin (P1Zn) were selected to be solubilized in cetyltrimethyl ammonium bromide (CTAB) micellar solutions. By taking advantage of the microenvironment sensitivity of their Soret band, UV-Vis spectra were used to study the dependence of location of the porphyrins in CTAB micellar media on the bulk pH value or the salt concentration of bulk solutions. The red shift of the Soret band, the decrease of its absorbance and the increase of the full width at half-maximum (FWHM) of P1Zn and P1 with pH titration process from neutral to weak basicity were attributed to the transfer process of the porphyrin moiety from the inner core to the outer surface of the micelles. In the pH sensitive area of the Soret band of P1Zn and P1, the blue shift of the Soret band, the increase of its absorbance and decrease of FWHM | ZHANG Yunhong MA Chen CHANG Hailong LI Qianshu FENG Juan AI Xicheng | 2000 | Chinese Science Bulletin2000，45，12： | 0 |
| 10 | Spectroscopic investigation on the telomeric DNA base sequence repeat显示文摘Telomeres are protein-DNA complexes at the terminals of linear chromosomes, which protect chromoso-mal integrity and maintain cellular replicative capacity. From single-cell organisms to advanced animals and plants, structures and functions of telomeres are both very conser-vative. In cells of human and vertebral animals, telomeric DNA base sequences all are (TTAGGG)n. In the present work, we have obtained absorption and fluorescence spectra measured from seven synthesized oligonucleotides to simu-late the telomeric DNA system and calculated their relative fluorescence quantum yields on which not only telomeric DNA characteristics are predicted but also possibly the shortened telomeric sequences during cell division are im-plied. Oligonucleotide 5’- TTAGGGTTAGGG holds a low relative fluorescence quantum yield and remarkable excitation energy innerconversion, which tallies with the telomeric sequence of (TTAGGG)n. This result shows that telomeric DNA has a strong non-radiative or innerconvertible capabil- | Sichuan Xu Xicheng Ai Zhaoyong Sun Qiyuan Zhang Xingkang Zhang | 2002 | Chinese Science Bulletin2002，47，2： | 0 |
| 11 | Fluorescence dynamics of interactions between polyamide PyPyPyβDp and DNA显示文摘The photophysical properties of the polyamide PyPyPyβDp (PPP) were investigated by means of steady-state absorption and fluorescence spectroscopies, as well as time-resolved fluo-rescence spectroscopy. It was found that the excited-state properties of PPP are very sensitive to solvents. In TKMC buffer PPP exhibited weak fluorescence with a decay time constant of 16 ps, while with the decrease of the solvent polarity PPP showed the blue-shifted peak position, increased inten-sity and lengthened life-time for its fluorescence behavior. In the presence of calf thymus DNA, it was observed that the fluorescence intensity was enhanced and the fluorescence lifetime increased from 16 to 32 ps for PPP, which verified that PPP bound into the minor groove of DNA duplex. | ZHANG Huijuan1,2, WANG Jin3, WU Yishi1, YUAN Gu3, AI Xicheng1, WANG Li4 & ZHANG Jianping1 1. State Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China 2. School of Life Science and Technology, Beijing Institute of Technology, Beijing 100081, China 3. College of Chemistry and Molecular Engineering, Peking University, Beijing 100080, China 4. Center for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, China Correspondence should be addressed to Ai Xicheng and Zhang Jianping | 2006 | Science China Chemistry2006，49，1： | 0 |
| 12 | Effects of different aggregation forms of LHC Ⅱ from Bryopsis corticulans on the excited state properties of Chl a显示文摘Steady-state and time-resolved fluo- rescence spectroscopies have been used to study the excited state properties of Chl a in different ag- gregation forms of light-harvesting complex II (LHC II) from an intertidal green alga, Bryopsis corticulans, i.e. LHC II monomer, trimer and oligomer. When either Chl a or Chl b was selectively excited, the observed decrease in Chl a fluorescence in the oligomer is proved to be caused mainly by the fast fluorescence quenching among Chl a molecules, rather than by the decrease in Chl b-to-Chl a singlet excitation transfer efficiency. Analyses of the picosecond time-resolved fluorescence kinetics identified two exponential de- cay components in all of the three forms of LHC II: a longer-lived component (4.1―4.7 ns) originating from fluorescence emission of Chl a, and a shorter-lived one (135―540 ps) from the rapid equilibration of singlet excitation among Chl a molecules. The time constant of excitation equilibration is 135 ps in oli- gomer, 520 ps in trimer and 540 ps in monomer. These results imply that LHC II in oligomer form is inherently able to quench Chl a excitation, a mecha- nism which may be related to the photoprotection of PS II via changing the degree of LHC II aggregation in Bryopsis corticulans. | ZUO Ping CHEN Hui WU Yishi SHEN Shihua WANG Peng AI Xicheng ZHANG Jianping LI Liangbi KUANG Tingyun | 2006 | Chinese Science Bulletin2006，51，12： | 0 |
| 13 | Study on time-resolved fluorescence dynamics of cyanine dye sensitizing AgBr显示文摘The fluorescence spectra of three different dyes adsorbed on the tabular and cubic AgBr microcrystals are obtained by the picosecond time-resolved streak camera technique. The dependence of the ultrafast electron transferring from dye-aggre-gates to the conduction band of AgBr and the efficiency of spectral sensitization on different kinds of dyes with different concentrations is analyzed. Further more,the microcosmic mechanism of the sensitization process is discussed. It is found that the fluorescence decay curves are fitted very well by the double exponential func-tion,consisting of a slow component and a fast one with large amplitude. We con-sider this fast one mainly attributable to the electron transfer from dye J-aggre-gates to the conduction band of AgBr. | YANG ShaoPeng FAN ShanShan LI ChunLei FAN GuoZhi MENG Tao LI XiaoWei FU GuangSheng AI XiCheng ZHAO XiaoHui YE JianPing WANG LingXuan | 2008 | Science China(Physics,Mechanics & Astronomy)2008，51，3： | 0 |
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