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991.
Wei Wang Dr. Parthasarathi Subramanian Oscar Martinazzoli Jun Wu Prof. Dr. Lutz Ackermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(45):10585-10589
Late-stage C−H glycosylations of structurally complex amino acids and peptides were accomplished by means of racemization-free manganese(I)-catalyzed C−H activation. Thus, glycosylative modifications proved to be viable by a linch-pin approach, featuring chemo- and site-selective C−H transformations. The peptide–saccharide conjugation provided modular access to structurally complex glycopeptides, likewise enabling the assembly of fluorescent-labelled glycopeptides. 相似文献
992.
Self‐Assembly: Surfactant‐Assisted Emulsion Self‐Assembly of Nanoparticles into Hollow Vesicle‐Like Structures and 2D Plates (Adv. Funct. Mater. 43/2016) 下载免费PDF全文
993.
Zhang YouMing Shi BingBing Zhang Peng Huo JianQiang Chen Pei Lin Qi Liu Jun Wei TaiBao 《中国科学:化学(英文版)》2013,56(5):612-618
Science China Chemistry - A non-sulfur chemosensor based on an easy to prepare double naphthalene Schiff base is reported for the colorimetric and fluorometric dual-channel sensing of Hg2+ ions by... 相似文献
994.
Canrong Lin Yuyuan Wang Li Zhou Jun Liang 《International journal of environmental analytical chemistry》2013,93(11):1050-1061
A novel ion-imprinted adsorbent for selective solid phase extraction of thorium(IV) based on the surface of silica gel was prepared by a surface-grafted technique with methacrylic acid (MAA) as a functional monomer. After removal of Th(IV) ions with 3?mol?L?1 HCl solution, the obtained imprinted particles for Th(IV) exhibited specific recognition and relatively rapid kinetic process. The maximum static and total dynamic adsorption capacity of the ion-imprinted polymers (IIPs) for Th(IV) was 33.2 and 17.3?mg?g?1, respectively. A comparison of the selectivity coefficient of the imprinted polymers with that of non-imprinted polymers showed that the imprinted matrix for Th(IV)/U(VI), Th(IV)/Ce(III), Th(IV)/La(III) and Th(IV)/Zr(IV) was 58.8, 107, 106.4 and 151.7 times greater than non-imprinted matrix, respectively. With a series of samples loading flow rate of 3?mL?min?1 for preconcentration, an enrichment factor of 14.6 and the detection limit of 0.59?µg?L?1 were obtained. The relative standard deviation of the method under optimum conditions was 2.1% (n?=?7). The developed method was successfully applied to the determination of trace Th(IV) in real water samples with satisfactory results. 相似文献
995.
996.
Synthesis and characterization of intrinsic high‐barrier polyimide derived from a novel diamine monomer containing rigid planar moiety 下载免费PDF全文
Yi‐Wu Liu Jie Huang Jing‐Hua Tan Yi Zeng Qian Ding Xian‐Wei Xiang Yue‐Jun Liu Hai‐liang Zhang 《Journal of polymer science. Part A, Polymer chemistry》2017,55(14):2373-2382
A new diamine monomer containing rigid planar fluorenone moiety, 2,7‐bis(4‐aminophenyl)‐9H‐fluoren‐9‐one, was synthesized through Suzuki coupling reaction. Then it was reacted with pyromellitic dianhydride to obtain a polyimide (FOPPI) via a conventional two‐step polymerization process. The prepared FOPPI exhibits excellent barrier properties, with the oxygen transmission rate and water vapor transmission rate low to 3.2 cm3·m?2·day?1 and 2.9 g·m?2·day?1, respectively. The results of wide angle X‐ray diffractograms, positron annihilation lifetime spectroscopy, and molecular dynamics simulations reveal that the excellent barrier properties of FOPPI are mainly ascribed to the crystallinity, high chain rigidity, and low free volume, which are resulted from the rigid planar moiety. FOPPI also shows outstanding thermal stability and mechanical properties with a glass transition temperature up to 420 °C, 5% loss temperature of 607 °C, coefficient of thermal expansion of 1.28 ppm K?1, and tensile strength of 150.8 MPa. The polyimide has an attractive potential application prospect in the flexible electronics encapsulation area. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 2373–2382 相似文献
997.
�� ������ �ƣ�¬ ������ �أ�������� ���������� 《核聚变与等离子体物理》2017,37(4):418-421
The power measurement method for 3.7GHz LHCD system on HL-2A was introduced. It is found by HFSS simulation that the impact of backward wave phase on the measurement of forward power may be suppressed if the isolation of directional coupler is more than 30dB. After improving the system, the total transmission line efficiency of the LHCD system can reach 89% with maximum power 1.5MW in 2016 experiment campaign. 相似文献
998.
LI Lianming NIU Xiaokang CHEN Linhui CHAI Yuan ZHANG Tao SHI Jun WANG Aili LUO Ying HE Long CHENG Depeng LIU Nan CUI Tiejun YOU Xiaohu 《中国通信》2014,(6)
With more than 40 years Moore scaling, the speed of CMOS transistors is around 100 GHz. Such fact makes it possible to realize mm-wave circuits in CMOS. However, with the target of achieving broadband and power-efficient operation, 60 GHz CMOS RF transceiver faces severe challenges. After reviewing the technology issues, regarding the 60 GHz applications, this paper discusses design challenges both from the system and the building block levels, and also presents some simulated or measured circuits results. 相似文献
999.
Da Yan He Zhan Jiang Li Zhong Jun Li Yun Qi Liu Dong Xu Qiu Meng Shen Cai 《合成通讯》2013,43(18):2653-2658
Cabohydrates reacting with acetone in the presence of molecular sieve and p—toluene sulfonic acid provided a simple, convenient, high yield and good selective process for preparation of isopropylidene carbohydrates. 相似文献
1000.