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排序方式: 共有1321条查询结果,搜索用时 15 毫秒
41.
Hao Huang Cuicui Du Hongyan Shi Xun Feng Jin Li Yanlei Tan Wenbo Song 《Particle & Particle Systems Characterization》2015,32(1):72-79
Uniform water‐soluble monolayer MoS2 quantum dots (MQDs) with lateral sizes of ≈2.1 nm, a clearly zigzag‐terminated edge, and a hexagonal lattice structure are achieved using ammonium molybdate, thiourea, and N‐acetyl‐l ‐cysteine (NAC) as precursors and the capping reagent in a facile one‐pot hydrothermal approach. MQDs have good dispersity and high stability in aqueous suspension and exhibit a significantly larger direct bandgap (3.96 eV) compared to monolayer MoS2 nanosheets (1.89 eV). Pronounced blue‐shifts in the wavelengths of both the excitonic absorption and intrinsic state emission with activated strong luminescence at room temperature beyond monolayer MoS2 nanosheets is demonstrated. Unusual upconversion photoluminescence is also observed and is caused by two successive transfers of energy from the near‐infrared (NIR) absorption generated by the NAC capping reagent to the hexagonal structure of MQDs. Additional optical properties of MQDs may provide numerous exciting technological applications. Here, MQDs are demonstrated as a highly selective fluorescent reagent for detecting tetracycline hydrochloride under UV and NIR irradiation. 相似文献
42.
We report a 1.8 μm two-section distributed Bragg reflector laser using butt-jointed In Ga As P bulk material as the waveguide core layer. The threshold current is 17 m A and the output power is 8 m W on average. The threshold current, output power, and emitting wavelength dependences on temperature are measured. The obtained wavelength tuning range is 10 nm. This device has potential applications in simultaneous multiple-gas detection. 相似文献
43.
Magnetically Encoded Luminescent Composite Nanoparticles through Layer‐by‐Layer Self‐Assembly
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Prof. Dr. Erqun Song Weiye Han Hongyan Xu Yunfei Jiang Dan Cheng Prof. Dr. Yang Song Prof. Dr. Mark T. Swihart 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(45):14642-14649
Sensitive and rapid detection of multiple analytes and the collection of components from complex samples are important in fields ranging from bioassays/chemical assays, clinical diagnosis, to environmental monitoring. A convenient strategy for creating magnetically encoded luminescent CdTe@SiO2@n Fe3O4 composite nanoparticles, by using a layer‐by‐layer self‐assembly approach based on electrostatic interactions, is described. Silica‐coated CdTe quantum dots (CdTe@SiO2) serve as core templates for the deposition of alternating layers of Fe3O4 magnetic nanoparticles and poly(dimethyldiallyl ammonium chloride), to construct CdTe@SiO2@n Fe3O4 (n=1, 2, 3, …?) composite nanoparticles with a defined number (n) of Fe3O4 layers. Composite nanoparticles were characterized by zeta‐potential analysis, fluorescence spectroscopy, vibrating sample magnetometry, and transmission electron microscopy, which showed that the CdTe@SiO2@n Fe3O4 composite nanoparticles exhibited excellent luminescence properties coupled with well‐defined magnetic responses. To demonstrate the utility of these magnetically encoded nanoparticles for near‐simultaneous detection and separation of multiple components from complex samples, three different fluorescently labeled IgG proteins, as model targets, were identified and collected from a mixture by using the CdTe@SiO2@n Fe3O4 nanoparticles. 相似文献
44.
Xiu-Jun Wang Ming-Li Yang Lan-Ping Zhang Tong Yao Cheng Chen Lian-Gang Mao Yin Wang Jie Wu 《中国化学快报》2014,25(4):589-592
A new series of bis-benzimidazole derivatives were designed and synthesized.In vitro cytotoxicity evaluation showed that these compounds exhibited high activity against the selected tumor cells.Among them,compound 9 owned the best potential,its IC_(50) values being 5.95 μmol/L(mononuclear tumor cell line(U937)) and 5.58 μmol/L(cervical cancer cell(HeLa)).Fluorescence and UV-vis studies showed that compound 9 could bind into the minor groove of DNA. 相似文献
45.
Hongyan Li Hong Ma Xinhong Wang Jin Gao Chen Chen Song Shi Minjie Qu Na Feng Jie Xu 《天然气化学杂志》2014,(6):742-746
Efficient catalytic oxidation of ethylbenzene to acetophenone was realized using the catalytic system of cobalt zeolitic imidazolate framework ZIF-67/N-hydroxyphthalimide (NHPI) under mild conditions. 95.2% conversion of ethylbenzene with 90.3% selectivity to acetophenone could be obtained at 373 K under 0.3 MPa 02 for 9 h. The results show that there exists synergetic effect between ZIF-67 and NHPI. 1-Phenylethyl hydroperoxide (PEHP) was generated via a radical process involving the hydrogen abstraction from ethylbenzene by phthalimide N-oxyl, and subsequently effectively decomposed to acetophenone by ZIF-67. 相似文献
46.
47.
Ya-Hang Wu Prof. Dr. Hongyan Xiao Prof. Dr. Bin Chen Prof. Dr. Richard G. Weiss Prof. Dr. Yu-Zhe Chen Prof. Dr. Chen-Ho Tung Prof. Dr. Li-Zhu Wu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(25):10259-10264
Three rigid and structurally simple heterocyclic stilbene derivatives, (E)-3H,3′H-[1,1′-biisobenzofuranylidene]-3,3′-dione, (E)-3-(3-oxobenzo[c] thiophen-1(3H)-ylidene)isobenzofuran-1(3H)-one, and (E)-3H,3′H-[1,1′-bibenzo[c] thiophenylidene]-3,3′-dione, are found to fluoresce in their neat solid phases, from upper (S2) and lowest (S1) singlet excited states, even at room temperature in air. Photophysical studies, single-crystal structures, and theoretical calculations indicate that large energy gaps between S2 and S1 states (T2 and T1 states) as well as an abundance of intra and intermolecular hydrogen bonds suppress internal conversions of the upper excited states in the solids and make possible the fluorescence from S2 excited states (phosphorescence from T2 excited states). These results, including unprecedented fluorescence quantum yields (2.3–9.6 %) from the S2 states in the neat solids, establish a unique molecular skeleton for achieving multi-colored emissions from upper excited states by “suppressing” Kasha's rule. 相似文献
48.
近年来,纳米药物递送系统在癌症治疗方面的应用受到广泛关注。 传统的纳米药物递送系统存在生物相容性差、靶向性缺乏、在肿瘤部位释药缓慢等问题。 本文设计制备了一种同源细胞膜(M)包覆、癌细胞还原微环境控制释药的脂质体纳米粒子(命名为P-ss-G/D/Sf@M)来递送肝癌治疗药物索拉非尼(Sf)用于肝癌的靶向治疗。 利用薄膜水化法结合静电吸附及过膜挤压法制备包覆细胞膜的空白(P-ss-G/D@M)及载药(P-ss-G/D/Sf@M)纳米粒子。 P-ss-G/D/Sf@M对Sf的载药量为7.2%,包封率为79.9%。 体外释药结果显示,P-ss-G/D/Sf@M在还原条件下会加快药物的释放,48 h时药物释放量达到65%以上,较非还原条件下释药量提高了25%。 体外细胞实验结果证明,包覆肝癌细胞膜的纳米粒子更易被肝癌细胞摄取,表现了对肝癌细胞的靶向性,同时在肿瘤细胞高浓度谷胱甘肽(GSH)还原环境作用下,纳米粒子中的二硫键断裂,迅速释放药物,与非还原敏感载药纳米粒子相比,显著抑制肝癌细胞生长,提高细胞凋亡率。 因此,本文制备的同源细胞膜包覆的智能释药载体有可能用于今后的癌症治疗中。 相似文献
49.
Origin用于物理化学实验数据的非线性拟合 总被引:4,自引:0,他引:4
在物理化学实验数据处理中应用Origin软件对数据进行非线性拟合,介绍用Origin求得实验曲线的非线性拟合参数的方法。结果表明,使用该软件能降低数据处理的随意性,减少处理误差,并且快捷方便,使实验结果更合理。 相似文献
50.
Can Liao Wei Wang Junling Wang Longfei Han Shuilai Qiu Lei Song Zhou Gui Yongchun Kan Yuan Hu 《Journal of Energy Chemistry》2021,(5):1-10
To date,lithium-ion batteries are becoming increasingly significant in the application of portable devices and electrical vehicles,and revolutionary progress in theoretical research and industrial application has been achieved.However,the commercial polyolefin separators with unsatisfying electrolytes affinity and poor thermal stability have extremely restricted the further application of lithium-ion batteries,especially in the high-temperature fields.In this work,magnetron sputtering deposition technique is employed to modify the commercial polyimide separator by coating silicon nitride on both sides.Magnetron sputtering deposition modified polyimide(MSD-PI)composite separator shows high thermal stability and ionic conductivity.More importantly,compared with the cells using Celgard separator,the cells with MSD-PI separator exhibit superior electrochemical performance,especially long-term cycle performance under high temperature environment,owing to the high thermal conductivity of surface Si3 N4 particles.Hence,lithium-ion batteries with MSD-PI separator are capable of improving thermal safety and capacity retention,which demonstrates that magnetron sputtering deposition technique could be regarded as a promising strategy to develop advanced organic/inorganic composite separators for high-temperature lithium-ion batteries. 相似文献