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138 results on '"Li, Yannian"'

1. Electrically tunable selective reflection of light from ultraviolet to visible and infrared by heliconical cholesterics

Author

Xiang, Jie, Li, Yannian, Li, Quan, Paterson, Daniel A., Storey, John M. D., Imrie, Corrie T., and Lavrentovich, Oleg D.

Subjects
Condensed Matter - Soft Condensed Matter, Condensed Matter - Materials Science, Physics - Optics
Abstract

Cholesteric liquid crystals with helicoidal molecular architecture are known for their ability to selectively reflect light with the wavelength that is determined by the periodicity of molecular orientations. Here we demonstrate that by using a cholesteric with oblique helicoidal(heliconical) structure, as opposed to the classic right-angle helicoid, one can vary the wavelength of selectively reflected light in a broad spectral range, from ultraviolet to visible and infrared (360-1520 nm for the same chemical composition) by simply adjusting the electric field applied parallel to the helicoidal axis. The effect exists in a wide temperature range (including the room temperatures) and thus can enable many applications that require dynamically controlled transmission and reflection of electromagnetic waves, from energy-saving smart windows to tunable organic lasers, reflective color display, and transparent see-through displays., Comment: 11 pages, 5figures

Published
2015
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4. Three-dimensional control of the helical axis of a chiral nematic liquid crystal by light

Author

Zheng, Zhi-gang, Li, Yannian, Bisoyi, Hari Krishna, Wang, Ling, Bunning, Timothy J., and Li, Quan

Subjects
Liquid crystals -- Properties -- Analysis, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

Chiral nematic liquid crystals--otherwise referred to as cholesteric liquid crystals (CLCs)--are self-organized helical superstructures that find practical application in, for example, thermography (1), reflective displays (2), tuneable colour filters (3,4) [...]

Published
2016

6. Study on food safety risk based on LightGBM model: a review

Author

Wang JING, Bi QIAN, and Li YANNIAN

Subjects
predictive model, risk points, fuzzy comprehensive risk values, risk management, Food Science, Biotechnology
Abstract

Accurately detecting risk points is crucial to food safety risk assessment and prewarning in food safety risk management because it helps solve food safety problems at their source. With the advancement of informationization in the food industry, a vast quantity of food safety data generated throughout sample inspection, transportation, storage, food processing, and raw material production has become urgently necessary to develop and use. Nevertheless, the existing food safety risk warning system has several flaws, including a high personnel cost, a low data utilization rate, and a crude risk measurement system. As a result, we described the data attributes for further analysis and sorted the food safety data in this study. In the meantime, to fully exploit the high dimension and the data's large amount, a mixture of fuzzy hierarchy partition and prior risk probability could be used to calculate fuzzy comprehensive risk values depending on multiple traits as the predicted outcome of a predictive model which can forecast and confirm risk levels, created with the use of a light gradient boosting machine (LightGBM) and skilled adjustment procedures. Finally, the outcomes of the multiple methods are compared using the same training and test data in order to verify the efficiency of LightGBM. The risk analysis results presented in this study, including attribute importance distribution and the risk values, can be useful to decision-makers.

Published
2022

10. Photonic Crystals: Light-Patterned Crystallographic Direction of a Self-Organized 3D Soft Photonic Crystal (Adv. Mater. 42/2017)

Author

Zheng, Zhi-Gang, primary, Yuan, Cong-Long, additional, Hu, Wei, additional, Bisoyi, Hari Krishna, additional, Tang, Ming-Jie, additional, Liu, Zhen, additional, Sun, Pei-Zhi, additional, Yang, Wei-Qiang, additional, Wang, Xiao-Qian, additional, Shen, Dong, additional, Li, Yannian, additional, Ye, Fangfu, additional, Lu, Yan-Qing, additional, Li, Guoqiang, additional, and Li, Quan, additional

Published
2017
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12. Light-Patterned Crystallographic Direction of a Self-Organized 3D Soft Photonic Crystal

Author

Zheng, Zhi-Gang, primary, Yuan, Cong-Long, additional, Hu, Wei, additional, Bisoyi, Hari Krishna, additional, Tang, Ming-Jie, additional, Liu, Zhen, additional, Sun, Pei-Zhi, additional, Yang, Wei-Qiang, additional, Wang, Xiao-Qian, additional, Shen, Dong, additional, Li, Yannian, additional, Ye, Fangfu, additional, Lu, Yan-Qing, additional, Li, Guoqiang, additional, and Li, Quan, additional

Published
2017
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18. Gratings: Light-Driven Wide-Range Nonmechanical Beam Steering and Spectrum Scanning Based on a Self-Organized Liquid Crystal Grating Enabled by a Chiral Molecular Switch (Advanced Optical Materials 2/2015)

Author

Jau, Hung-Chang, primary, Li, Yannian, additional, Li, Cheng-Chang, additional, Chen, Chun-Wei, additional, Wang, Chun-Ta, additional, Bisoyi, Hari Krishna, additional, Lin, Tsung-Hsien, additional, Bunning, Timothy J., additional, and Li, Quan, additional

Published
2015
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27. Organo-Soluble Chiral Thiol-Monolayer-Protected Gold Nanorods

Author

AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE, Li, Yannian, Yu, Dingshan, Dai, Liming, Urbas, Augustine, Li, Quan, AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH MATERIALS AND MANUFACTURING DIRECTORATE, Li, Yannian, Yu, Dingshan, Dai, Liming, Urbas, Augustine, and Li, Quan

Abstract

Here, we report the synthesis and characterization of organo-soluble chiral thiol-monolayer-protected gold nanorods. The resulting gold nanorods respectively covered with two opposite enantiomers via the strong covalent Au-S linkage were found to not only be stable in both organic media and solid state, but also show optical activity. Their circular dichroism (CD) spectra exhibited a mirror image relationship, indicating that enantiomeric thiol surfactant on gold surface can produce the corresponding enantiomeric gold nanorods. The densely packed azobenzene thiolmonolayer on gold surface exhibited a photoresponsive behavior upon irradiation with 254 nm light instead of 365nm light, which was found to have an effect on plasmonic absorption of gold nanorods., Published in Langmuir, v27 n1 p98-103, 2011. Prepared in cooperation with the Liquid Crystal Institute, Kent State University, Kent, OH, and the Department of Chemical Engineering, Case Western Reserve University, Cleveland, OH.

Published
2011

28. Total synthesis of (4S,10R)-4-hydroxy-10-methyl-11-oxododec-2-en-1,4-olide and related bioactive marine butenolides

Author

Dai, Wei-Min, Shi, Lei, Li, Yannian, Dai, Wei-Min, Shi, Lei, and Li, Yannian

Abstract

Marine-derived microorganisms produce structurally diverse butenolides possessing a variety of bioactivities. Described here is the total synthesis of (4S, 10R)-4-hydroxy-10-nnethyl-11-oxododec-2-en-1,4-olide and a related butenolide containing anti stereochemistry at C10-C11. A three-module coupling strategy has been established for synthesis of the stereoisomers of the naturally Occurring butenolides by assembling the C3-C7 and C9-C12 fragments via double alkylation of a 1,3-dithiane. The C10-C11 stereochemistry could be easily controlled by an asymmetric aldol condensation, while the butenolide unit was efficiently constructed according to the ring-closing metathesis protocol. (C) 2008 Elsevier Ltd. All rights reserved.

Published
2008

29. Generation of an aromatic amide-derived phosphane (Aphos) library by self-assisted molecular editing and applications of Aphos in room-temperature Suzuki-Miyaura reactions

Author

Dai, Wei-Min, Li, Yannian, Zhang, Ye, Yue, Congyong, Wu, Jinlong, Dai, Wei-Min, Li, Yannian, Zhang, Ye, Yue, Congyong, and Wu, Jinlong

Abstract

Aromatic amide-derived phosphanes (Aphos) are hemilabile P,O-coordinating ligands, which, when combined with a Pd precursor, yield a promising precatalyst system for Suzuki-Miyaura cross-coupling reactions. A focused library of Aphos ligands has been constructed for structural optimization, with the target of improving catalytic efficacy. By using microwave irradiation at accurately regulated temperature, an expeditious and reproducible one-pot synthesis and screening protocol was designed and experimentally validated. The success is based on a unique self-assisted molecular editing (SAME) process in which both the substrate and the product molecules catalyze formation of the product. Thus, starting from a 4-chlorobenzamide-derived Aphos as the substrate, parallel reactions with a selected set of arylboronic acids, in the absence of an added external phosphane ligand to Pd, produced a family of structurally edited Aphos ligands. The resultant reaction mixture containing the new Aphos, the Pd species, and the base could be used for in situ screening of the Aphos efficacy in a reference Suzuki-Miyaura coupling reaction. The structures of all Aphos ligands were characterized by P-31 NMR spectroscopy and their catalytic profiles in the reference reaction were evaluated by HPLC analysis. These data allowed the identification of an efficient Aphos ligand, capable of promoting room-temperature Suzuki-Miyaura coupling of unactivated and sterically hindered aryl chlorides with arylboronic acids under mildly basic conditions.

Published
2008

35. Total synthesis of amphidinolide y by formation of trisubstituted (E)-double bond via ring-closing metathesis of densely functionalized alkenes

Author

Jin, Jian, Chen, Yile, Li, Yannian, Wu, Jinlong, Dai, Wei-Min, Jin, Jian, Chen, Yile, Li, Yannian, Wu, Jinlong, and Dai, Wei-Min

Abstract

Amphidinolide Y, a 17-membered cytotoxic macrolide isolated from marine dinoflagellates, has been synthesized via ring-closing metathesis to assemble the congested trisubstituted (E)-double bond. The seco precursor was prepared from readily available chiral synthons with the tetrahydrofuran ring formed via 5-endo epoxide ring-opening cyclization. It was found that the C6-keto seco substrate showed higher reactivity toward Grubbs' second generation catalyst while Schrock's Mo catalyst was completely inactive for formation of the macrocycle.

Published
2007

49. Light-Directing Omnidirectional Circularly Polarized Reflection from Liquid-Crystal Droplets.

Author

Fan, Jing, Li, Yannian, Bisoyi, Hari Krishna, Zola, Rafael S., Yang, Deng-ke, Bunning, Timothy J., Weitz, David A., and Li, Quan

Subjects
*LIQUID crystal devices, *NANOFABRICATION, *DROPLETS, *CHOLESTERIC liquid crystals, *IRRADIATION
Abstract

Constructing and tuning self-organized three-dimensional (3D) superstructures with tailored functionality is crucial in the nanofabrication of smart molecular devices. Herein we fabricate a self-organized, phototunable 3D photonic superstructure from monodisperse droplets of one-dimensional cholesteric liquid crystal (CLC) containing a photosensitive chiral molecular switch with high helical twisting power. The droplets are obtained by a glass capillary microfluidic technique by dispersing into PVA solution that facilitates planar anchoring of the liquid-crystal molecules at the droplet surface, as confirmed by the observation of normal incidence selective circular polarized reflection in all directions from the core of individual droplet. Photoirradiation of the droplets furnishes dynamic reflection colors without thermal relaxation, whose wavelength can be tuned reversibly by variation of the irradiation time. The results provided clear evidence on the phototunable reflection in all directions. [ABSTRACT FROM AUTHOR]

Published
2015
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