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排序方式: 共有1592条查询结果,搜索用时 31 毫秒
1.
Difeng Yin Yucen Li Lingling Xia Wenbo Li Wei Chu Jianping Yu Miao Wu Ya Cheng Ming Hu 《中国化学快报》2022,(2):1077-1080
Despite the continuously increased requirement on automated synthesis of medicines for distributed manufacturing and personal care, it remains a challenge to realize automated synthesis which requires solid-liquid phase reactions. In this work, we demonstrated an automated solid-liquid synthesis for gadopentetate dimeglumine, the most widely used magnetic resonance imaging(MRI) contrast agent. The high-efficiency reaction was performed in a 3 D microfluidic chip which was fabricated by femtoseco... 相似文献
2.
Understanding and control of the surface properties such as molecular orientations are of great importance in numerous applications of ionic liquids. However, there remain discrepancies among the previous experimental and theoretical studies on the surface orientation and structures of room temperature ionic liquids(RTIL) systems. In this article, the orientation of 1-butyl-3-methylimidazolium([bmin]) cation at the air/liquid interface of a characteristic RTIL, 1-butyl-3-methylimidazolium hexafluorophosphate([bmim][PF6]), was investigated by the sum frequency generation vibrational spectroscopy(SFG-VS). Detailed polarization and experimental configuration analyses of the SFG-VS spectra showed the possibility of a small spectral splitting in the CH3 symmetric stretching region, which can be further attributed to the probable existence of multiple orientations for the interfacial [bmim] cations. In addition, the(N)–CH3 vibrations were absent, ruling out the prediction by several recent molecular dynamics simulations which state that portions of the [bmim] cations orient with a standing-up(N)–CH3 group at the ionic liquid surface. Hence, new realistic theoretical models have to be developed to reflect the complex nature of the ionic liquid surface. 相似文献
3.
WU DeSheng WANG Xia ZHANG Xu YANG ChongLi ZHENG Ping LI PeiGang SHI YouGuo 《中国科学:物理学 力学 天文学(英文版)》2015,(1):139-144
Cd3As2 was recently identified as a novel three-dimensional(3D)topological semimetal hosting the long-pursuing 3D Dirac Fermion.Crystals of Cd3As2 grown preferentially along the[100]and[112]directions were obtained through the modified chemical vapor transfer growth method,thus allowing the examination of transport anisotropy.The resistivity and magnetoresistance(MR)are basically linear with respect to magnetic field(H)in the measured temperature range of 2–300 K irrespective of the directions.The linear resistivity and MR are significantly anisotropic not only along[100]and[112]directions but also with respect to tilt angle between the growth directions and H,thus providing transport signatures of the 3D Dirac Fermion as well as the possible linear and anisotropic change of Weyl Fermi surface in H.Very large MR along the[100]direction is observed,even approaching 3100%at 2 K and 14 k Oe(1 Oe=79.5775 A m-1).The results would be helpful in renewing interest in studying emergent phenomena arising from bulk 3D Dirac Fermion as well as in paving the way for Cd3As2 to be used in magnetoelectronic sensors. 相似文献
4.
电站锅炉系统性能仿真模型的建立 总被引:1,自引:0,他引:1
1引言根据热力学第二定律,燃料中的化学拥将近一半损失在锅炉的燃烧与传热过程中。因此,优化锅炉性能对降低整个火电机组的煤耗率具有明显效果。完整的锅炉系统由磨煤机、送风机、一次风机、弓讯机、炉膛、汽包、过热器、再热器、省煤器、空气预热器等单元组成,这些单元之间的联结错综复杂。本文建立了锅炉系统中通用单元的性能模型,并在此基础上,对锅炉系统的结构特点进行了分析,利用过程系统工程中的序贯模块法建立了整个锅炉系统的性能模型。对单元的划分、回路的切断及断裂流股的收敛与迭代策略提出了自己的观点。最后根据生产厂… 相似文献
5.
Wei Wang Li-Ping Pang Zun-Quan Xia 《应用数学学报(英文版)》2007,23(1):29-38
In this paper,the UV-theory and P-differential calculus are employed to study second-order ex-pansion of a class of D.C.functions and minimization problems.Under certain conditions,some properties ofthe U-Lagrangian,the second-order expansion of this class of functions along some trajectories are formulated.Some first and second order optimality conditions for the class of D.C.optimization problems are given. 相似文献
6.
ThefascinatingsbocturesandpropertiesoffullereneshaveoPeneduPanewfieldofchendstry.Inparticular,F.Wudletal.l'2haveshownthatwatersofubleC6ocomPoundsinhibittheHITVen-zymesprotease(HIVP)andreversetranscriPtase(HIVRT).IthasbeenafocusofstUdytoinvestigatethebiologicalactivitiesofthesenovelsubstances.Fortheirpossiblemedicaluses,tolinkC6omoleculetonaturalProductssuchassugars,pephdes,amioacides,andsoonisanimPortantmethodinthisfield.Vasella3reportedthefirstglucosidederivativeofC6o'InthispaPer,w… 相似文献
7.
Guo Yang Zhu Rong Wang Guo Hua Liu Li Qun Xu Bei Zhang Xia Qin Wu College of Life Environment Science Shanghai Normal University Shanghai China State Key Laboratory of Chema/Biosensing Chemometrics Hunan University Changsha China 《中国化学快报》2007,18(6):633-635
Starting from the hydroxylamine (dimethyl amino ethanol, triethanolamine) and 1,3-propane sultone, a series of hydroxyl and sulfonyl dual-functionalized zwitterionic salts and corresponding acidic room temperature ionic liquids have been synthesized. The hydroxyl groups of the synthesized substances were confirmed by the 1H NMR measurement. These zwitterionic salts and ionic liquids may be used for synthesizing other functionalized ionic liquids or ionic liquid-polymer (polyelectrolyte). 相似文献
8.
The formation of covalently linked composites of multi–walled carbon nanotubes (MWCNT) and glucose oxidase (GOD) with high-function
density for use as a biosensing interface is described. The reaction intermediates and the final product were characterized
by using FT–IR spectroscopy, and the MWCNT-coated GOD nanocomposites were examined by atomic force microscopy (AFM) and transmission
electron microscopy (TEM). Interestingly, it was found that the GOD–MWCNT composites are highly water soluble. Electrochemical
characterization of the GOD–MWCNT composites that were modified on a glassy carbon electrode shows that the covalently linked
GOD retains its bioactivity and can specifically catalyze the oxidation of glucose. The oxidation current shows a linear dependence
on the glucose concentration in the solution in the range of 0.5–40 mM with a detection limit of 30 μM and a detection sensitivity
of 11.3 μA/mMcm2. The present method may provide a way to synthesize MWCNT related composites with other biomolecules and for the construction
of enzymatic reaction-based biofuel cells and biosensors.
Supported by grants from the National Natural Science Foundation of China (NSFC, No. 20125515; 90206037; 20375016) and the
Natural Science Foundation of Jiangsu Province (Grant No. BK 2004210) 相似文献
9.
Wei ZHANG Ni SONG Zhong Zhen LI Ying Xia LI 《中国化学快报》2006,17(3):285-288
Obyanamide 1 is a cyclic depsipeptide that was recently isolated from the marine cyanobacterium Lyngbya confervoides by Moore and co-workers1. This compound displayed a potent inhibitory effect on both KB and LoVo cells in vitro. Several structural analog… 相似文献
10.
In the present paper, we describe a microfluidics-based sensing system for nonelectroactive anions under negative separation electric field by mounting a single carbon fiber disk working electrode (WE) in the end part of a poly(dimethylsiloxane) microchannel. In contrast to work in a positive separation electric field described in our previous paper (Anal. Chem. 2004, 76, 6902-6907), here the electrochemical reduction reaction at the WE is not coupled with the separation high-voltage (HV) system, whereas the electrochemical oxidation reaction at the WE is coupled with the separation HV system. The electroactive indicator is the carbon fiber WE itself but not dissolved oxygen. This provides a convenient and sensitive means for the determination of nonelectroactive anions by amperometry. The influences of separation voltage, detection potential, and the distance between the WE and the separation channel outlet on the response of the detector have been investigated. The present detection mode is successfully used to electrochemically detect F-, Cl-, SO4(2-), CH3COO-, H2PO4-. Based on the preliminary results, a detection limit of 2 microM and a dynamic range up to three orders of magnitude for Cl- could be achieved. 相似文献