中国科学院机构知识库网格系统: 检索

A New Ingenane Diterpenoid from Euphorbia jolkinii 期刊论文 OAI收割
RECORDS OF NATURAL PRODUCTS, 2023
作者: Liu,Wen-Xing; Zhang,Ying-Jun; Zhou,Min; Zhao,Ping

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收藏 | 浏览/下载：11/0 | 提交时间：2024/05/09

Mid-late Pleistocene glacial evolution in the Grove Mountains, East Antarctica, constraints from cosmogenic Be-10 surface exposure dating of glacial erratic cobbles 期刊论文 OAI收割
QUATERNARY SCIENCE REVIEWS, 2016, 卷号: 145, 期号: 0, 页码: 71-81
作者: Dong, GC (Dong, Guocheng); Huang, FX (Huang, Feixin); Caffee, MW (Caffee, Marc W.); Huang, FX; Yi, CL (Yi, Chaolu)

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收藏 | 浏览/下载：29/0 | 提交时间：2017/09/26

Glacial HisTories From The East Antarctic Ice Sheet (Eais) Provide Keys To UnderstAndIng Correlations Between The Eats And Global Climate. They Are Especially Helpful In The Assessment Of Global Sea Level Change And As a Means Of Quantifying The Magnitude Of pAst Glacial Activity And The RAte At Which Ice Responded To climAte Change. Given The Significance Of Eais Glacial hisTories It Is Imperative That More Glacial Chronologic Data For thIs Region Be Obtained Especially For The Mid-to-lAte Pleistocene. We Report Cosmogenic Be-10 Surface Exposure DAtIng Results From Glacially Transported Cobbles Embedded In Blue-ice moraIne MAterial At Mount hardIng The Grove Mountains Eais. Forty Exotic Cobbles Sampled AlOng Two PrOfiles (a And b) On This Blue-ice MoraIne Present Apparent Exposure-ages RangIng From 7.2 To 542.2 Ka. We Explore This Scattered Dataset By UsIng PrIncipal compOnent Analysis (Pca) To Identify Statistically Significant Trends In The Data. We Identify a correlatiOn betWeen Exposure-age And Distance Of The Cobbles From Mount hardIng. In prOfile a Cobbles Further From Mount HardIng Yield Older Exposure-ages Than Those That Are Relatively Close. In Profile b Cobbles Closer To Mount HardIng Are Found To Have Relatively Older Exposure-ages. In Term Of Glacial hisTory We Suggest That The Direction Of Ice Flow Changed durIng The Period From Similar To 60 To 200 Ka And That Multiple Glacial Fluctuations Occurred In The Mid-late Pleistocene. (c) 2016 Elsevier Ltd. All Rights Reserved.

Synthesis, characterization, and ethylene polymerization behaviors of late-transition metal complexes coordinated with chlorinated bis(arylimino)pyridine ligand 期刊论文 OAI收割
polymer, 2014, 卷号: 55, 期号: 18, 页码: 4611-4618
Liu, Heng; Wang, Feng; Liu, Li; Jai,Xiang-Yu; Zheng,Wenjie; Guo,Jun; Zhang,Chun-Yu; Bai,Chen-Xi; Hu,Yan-Ming; Zhang,Xue-Quan

收藏 | 浏览/下载：34/0 | 提交时间：2015/10/20

A series of late-transition metal complexes supported with chlorinated bis(arylimino)pyridine ligands [2 Ar = 2 Ar = 2 Ar = 2 Ar = 4-Cl-2 Ar = 4-Br-2 6-(ArN=CCl)(2)C5H3N]MtCl(2) (Ar = 2 6-(Pr2C6H3)-Pr-i 6-Et2C6H3 6-Me2C6H3 6-Me2C6H2 6-Me2C6H2 4 Mt = Fe (1b) Mt = Co (1c) Mt = Fe (1d) Mt = Fe (1e) Mt = Fe (1f) 6-Me3C6H2 Co (2b) Ni (3c) Co (2d) Co (2e) Co (2f)) were synthesized. At the presence of methylaluminoxane (MAO) Mt = Fe (1a) Fe(II)- and Co(II)- based complexes were highly active towards ethylene polymerization Co (2a) affording polymers with bimodal and unimodal molar. mass distributions Ni (3a) respectively while the Ni(II)-based complexes gave no polymer products. Moreover the obtained polyethylenes were predominately saturated and vinyl-terminated for Fe(II)- and Co(II)-based complexes respectively. Changing the ligand environment polymerization parameters also posed a great influence on the catalytic activities and the properties of the resulting polymers. (C) 2014 Elsevier Ltd. All rights reserved.

Effect of Zn doping on the hydrogenolysis of glycerol over ZnNiAl catalyst 期刊论文 OAI收割
journal of molecular catalysis a-chemical, 2014, 卷号: 395, 页码: 1-6
Li, Xiaoru; Zhang, Chao; Cheng, Haiyang; He,Limin; Lin,Weiwei; Yu,Yancun; Zhao,Fengyu

收藏 | 浏览/下载：87/0 | 提交时间：2015/10/20

Nickel based catalyst is of interest in the industrial catalytic processes and it is always modified by doping a second element to improve its catalytic properties. Understanding the role of dopant is extremely helpful in tailoring the active centers. In this work Zn could induce a significant improvement of the catalytic performance of NiAl for the hydrogenolysis of glycerol. The Zn doped ZnNiAl catalysts exhibited high activity and the improved selectivity to 1 2-propanediol it was about 2 times higher than the original ones. The ZnNi alloy formed in ZnNiAl was responsible for the noticeable catalytic performance. They preferred to coordinate with the end hydroxyl group of glycerol promoted the cleavage of C-O bond in glycerol and resulted in the dominant formation of 1 2-propanediol. The findings described here will provide a useful knowledge for rational design of nickel-based catalysts as well as reveal a new reaction model for the hydrogenolysis of glycerol. (C) 2014 Elsevier B.V. All rights reserved.

Analysis of zenith pass problem and tracking strategy design for roll-pitch seeker (EI CONFERENCE) 会议论文 OAI收割
作者: Jiang H.

收藏 | 浏览/下载：18/0 | 提交时间：2013/03/25

Roll-pitch seeker is currently applied in particular missiles. There is a stubborn problem called zenith pass problem while roll-pitch seeker is used. Analysis of the zenith pass problem which always results in loss of target is presented in this paper. Based on the analysis result tracking strategy is carried out to deal with zenith pass problem. To prove the validity of tracking strategy a practical roll-pitch seeker was accomplished. Model identification and common PID controllers for the physical roll-pitch seeker are taken on after that both disadvantages derived from zenith pass problem in tracking process and meliorated phenomenons by the tracking strategy are shown. It is concluded that the tracking strategy designed for solving the zenith pass problem is efficient. 2011 Elsevier Masson SAS. All rights reserved.

Experimental study on formability of bulk metallic glass as mold for microstructure replication (EI CONFERENCE) 会议论文 OAI收割
作者: Liu J.; Lin J.; Huang Y.; Liu J.; Liu J.

收藏 | 浏览/下载：51/0 | 提交时间：2013/03/25

La62Al14Cu12Ni12BMG is introduced as a substitute for silicon which was widely used as mold material for nanofabrication. For the purpose of precise microstructure replication and complete filling effects of various imprint parameters including imprint temperature imprint time and compression load on formability of La 62Al14Cu12Ni12BMG are studied and discussed. Scanning electron microscope images and results of thermal analysis are used to characterize the filling effect of La62Al 14Cu12Ni12BMG. In particular correlations between time and thermodynamic properties are presented. Despite of its high viscosity at crystallization temperature and its narrow supercooled liquid region La62Al14Cu12Ni12BMG is proved to be a durable and promising material which can precisely replicate the patterns of silicon mold and then transfer its own patterns on Ce 69Al10Cu20Co1BMG and PMMA. 2012 Elsevier B.V. All rights reserved.

A glycine ligand coordinated hybrid complex constructed from hexanuclear copper clusters and octamolybdates 期刊论文 OAI收割
Inorganic Chemistry Communications, 2011, 卷号: 14, 期号: 9, 页码: 1546-1549
X. Y. Jiang; X. Y. Wu; R. M. Yu; D. Q. Yuan; W. Z. Chen

收藏 | 浏览/下载：37/0 | 提交时间：2012/06/06

Self-assembly of the sodium molybdate copper chloride and glycine in aqueous solution results in a novel compound {(NaCu(6)(Gly)(8)(H(2)O)(2)][Mo(8)O(26)(GlyH)(2)(Cu(Gly)H(2)O)](2)}{NaCu (6)(Gly)(8)(H(2)O)(2)}{ Mo(8)O(26)(GlyH)(2))center dot 16H(2)O (1). Compound 1 contains a new unit of {[NaCu(6)(Gly)(8)(H(2)O)(2)][Mo(8)O(26)Cu(Gly)(2)I(2)) in which the [Mo(8)O(26)Cu(Gly)(2)] polyoxometalate units are connected by the [NaCu(6)(Gly)(8)(H(2)O)(2)] hexanuclear copper cluster. The magnetic measurement of 1 shows that ferromagnetic coupling exists between the magnetic centers of the hexanuclear copper cluster. (C) 2011 Elsevier BV All rights reserved. building units polyoxometalate chemistry polymer oxides

Energy transfer in Y3Al5O12:Ce 3, Pr3+ and CaMoO4:Sm3, Eu 3 phosphors (EI CONFERENCE) 会议论文 OAI收割
作者: Wang L.; Wang X.-J.; Zhang X.; Zhang X.; Zhang X.

收藏 | 浏览/下载：37/0 | 提交时间：2013/03/25

Non-radiative energy transfers (ET) from Ce3 to Pr3+ in Y3Al5O12:Ce3 Pr3+ and from Sm3 to Eu3 in CaMoO4:Sm3 Eu3 are studied based on photoluminescence spectroscopy and fluorescence decay patterns. The result indicates an electric dipoledipole interaction that governs ET in the LED phosphors. For Ce3 concentration of 0.01 in YAG:Ce3 Pr3+ the rate constant and critical distance are evaluated to be 4.510-36 cm 6 s-1 and 0.81 nm respectively. An increase in the red emission line of Pr3+ relative to the yellow emission band of Ce 3 on increasing Ce3 concentration is observed. This behavior is attributed to the increase of spectral overlap integrals between Ce3 emission and Pr3+ excitation due to the fact that the yellow band shifts to the red spectral side with increasing Ce3 concentration. In CaMoO4:Sm3 Eu3 Sm 3Eu3 transfer occurs from 4G5/2 of Sm3 to 5D0 of Eu3. The rate constant of 8.510-40 cm6 s-1 and the critical transfer distance of 0.89 nm are evaluated. 2010 Elsevier B.V. All rights reserved.

Structural and photoluminescence properties of aligned Sb-doped ZnO nanocolumns synthesized by the hydrothermal method (EI CONFERENCE) 会议论文 OAI收割
作者: Wang X.; Wang X.; Wang X.; Li B.; Li B.

收藏 | 浏览/下载：24/0 | 提交时间：2013/03/25

Aligned Sb-doped ZnO nanocolumns were synthesized by a simple hydrothermal method. Based on the analyses of the X-ray diffraction and photoluminescence result it could be confirmed that the Sb has successfully doped in the ZnO crystal lattices to form an accepter energy level. At 85 K the recombination of the acceptor-bound exciton was predominant in PL spectrum which was attributed to the transition of the (SbZn-2VZn) complex bound exciton. The acceptor binding energy had been calculated to be 123 meV. 2009 Published by Elsevier B.V. All rights reserved.

Effect of interface on luminescence properties in ZnO/MgZnO heterostructures (EI CONFERENCE) 会议论文 OAI收割
Wei Z. P.; Lu Y. M.; Shen D. Z.; Wu C. X.; Zhang Z. Z.; Zhao D. X.; Zhang J. Y.; Fan X. W.

收藏 | 浏览/下载：30/0 | 提交时间：2013/03/25

A set of ZnO/MgZnO heterostructures with well widths Lw varying from 2 to 20 nm has been grown by plasma-assisted molecular-beam epitaxy (P-MBE). We present a room-temperature (RT) study of the well-width-dependent photoluminescence (PL) spectra and carrier lifetimes in ZnO/MgZnO heterostructures. Bi-exponential process is seen at RT time-decay curves of the luminescence from the well layers. The fast process is from the recombination of the free exciton while the slow process is attributing to the recombination of the localized exciton in the interface of ZnO and MgZnO. It is also confirmed from the PL peak shift of time-resolved PL spectra. With decreasing the well thickness the fast process gradually increases and dominantly contributes to the PL spectrum due to the interface improvement. 2006 Elsevier B.V. All rights reserved.