中国科学院机构知识库网格系统: 检索

The value of universally available raw NMR data for transparency, reproducibility, and integrity in natural product research 期刊论文 OAI收割
NATURAL PRODUCT REPORTS, 2019, 卷号: 36, 期号: 1, 页码: 35-107
作者: McAlpine, James B.; Chen, Shao-Nong; Kutateladze, Andrei; MacMillan, John B.; Appendino, Giovanni

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收藏 | 浏览/下载：40/0 | 提交时间：2020/07/08

NUCLEAR-MAGNETIC-RESONANCE MACROCYCLIC LACTONE ANTIBIOTICS MONOTERPENOID INDOLE ALKALOIDS UNPRECEDENTED CARBON SKELETON PROTON COUPLING-CONSTANTS A-TYPE PROANTHOCYANIDINS SULFUR-CONTAINING AMIDES STRUCTURE ELUCIDATION MARINE SPONGE PROPOSED STRUCTURE

Gradient Structure-Induced Temperature Responsiveness in Styrene/Methyl Methacrylate Gradient Copolymers Micelles 期刊论文 OAI收割
macromolecular rapid communications, 2014, 卷号: 35, 期号: 3, 页码: 309-316
Zheng,Chao; Huang,Haiying; He,Tianbai

收藏 | 浏览/下载：25/0 | 提交时间：2015/10/15

In this work micelles are formed by gradient copolymer of styrene and methyl methacrylate in acetone-water mixture and their temperature responsiveness is investigated in a narrow range near room temperature. Three different kinds of structural transitions could be induced by temperature: unimers to micelle transition shrinkage/stretching of micelles and morphological transition from spherical micelles to vesicles. In addition a model analysis on the interface of gradient copolymer micelle is made to better understand these phenomena. It is found that both position and composition of the interface could alter in response to the change in temperature. According to the experiments and model analysis it is proposed that temperature responsiveness might be an intrinsic and universal property of gradient copolymer micelles which only originates from the gradient structure.

Image quality assessment based on complex representation of structure information (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Electrical, Information Engineering and Mechatronics, EIEM 2011, December 23, 2011 - December 25, 2011, Jiaozuo, Henan, China
作者: Wang Y.; Wang Y.; Wang Y.; Wang Y.; Wang Y.

收藏 | 浏览/下载：31/0 | 提交时间：2013/03/25

Local variance and single pixel value are combined to describe image structure information using complex method in this paper in order to improve the consistency of objective image assessment result with that of subjective method. The effect of the detail structure information on the image quality was emphasized by this method accordingly. Singular value decomposition was performed on local variance distribution complex matrix. The angle between the singular value vectors of the reference image and the disturbed image was used to measure their structural similarity. Then the quality assessment process was achieved. Results from experiments show that the proposed method is better consistent with human visual system characteristics than MSE PSNR and SSIM. 2012 Springer-Verlag London Limited.

Application of adaptive enhancement means in head and neck CR image (EI CONFERENCE) 会议论文 OAI收割
2012 3rd International Conference on Information Technology for Manufacturing Systems, ITMS 2012, September 8, 2012 - September 9, 2012, Qingdao, China
Zhang M.-H.; Zhang Y.-Y.

收藏 | 浏览/下载：39/0 | 提交时间：2013/03/25

Digital CR of head and neck overcomes the disadvantage of regular X-ray radiography which can not reveal bone and soft tissue position deficiency in one exposing and reduces the Xray radiation dose. Meanwhile various factors cause the decline of image quality and images must be enhanced in order to meet demands of doctor's clinical diagnosis. The general enhancement algorithms don't consider body's structure differences and density characteristics. A new adaptive CR enhancement algorithm was proposed in this article and head and neck CR images were processed with this method and compared with linear unsharp masking method. The experiment proves that the details of CR image enhanced were abundant and enhanced CR image had good visual effect SNR was high as well as detail variance /background variance (DV/BV) indicating that this algorithm is suitable for head and neck CR medical images. (2012) Trans Tech Publications Switzerland.

Trajectory tracking control of a quad-rotor UAV based on command filtered backstepping (EI CONFERENCE) 会议论文 OAI收割
2012 3rd International Conference on Intelligent Control and Information Processing, ICICIP 2012, July 15, 2012 - July 17, 2012, Dalian, China
Gong X.; Bai Y.; Peng C.; Zhao C.; Tian Y.

收藏 | 浏览/下载：34/0 | 提交时间：2013/03/25

A quad-rotor unmanned aerial vehicle is an under-actuated strong coupled nonlinear system with parameters uncertainty and unknown external aerodynamic disturbance. The trajectory tracking control system with a nested double-loops structure is designed in this paper according to the coupling characteristic between the attitude angles and translational position. A PD control algorithm is proposed in the translational outer-loop to export the desired attitude signals to the attitude inner-loop. An adaptive backstepping control algorithm is designed in the inner-loop with respect to the uncertain rotational inertia and un-modeled disturbance while in order to reduce the computational complexity the command filtered approach is introduced into the designing procedure. And finally the numerical simulation results are presented for the trajectory tracking stabilization of a Quad-rotor which demonstrates the excellent performance of the proposed control system and illustrate its robustness in face of disturbance and uncertain parameters. 2012 IEEE.

LED display panel grayscale modulation based on computer calculation (EI CONFERENCE) 会议论文 OAI收割
2012 International Applied Mechanics, Mechatronics Automation Symposium, IAMMAS 2012, September 7, 2012 - September 9, 2012, Shenyang, Liaoning, China
Wang R.-g.; Chang F.

收藏 | 浏览/下载：27/0 | 提交时间：2013/03/25

In order to improve the method of the LED display panel grayscale modulation a method based on computer calculation is proposed. First the development history and trends of the LED display panel are introduced. Second present the structure of the LED display panel and the existed modulation method. Simultaneously point out the ground for shortcomings of the existed method. Third describe the principle modulation method based on computer calculation detail from two steps which are the data signal transformation and the grayscale modulation. Forth describe the realization steps of this method in accordance with the third step. Finally this method is supplied in a LED display panel whose resolution is 320240. Experimental results show that this method is able to increase the grayscale from 14-bit to 16-bit and can enhance the display result of the LED display panel significantly. (2012) Trans Tech Publications Switzerland.

Modeling and variable structure control of a vehicle flexible manipulator (EI CONFERENCE) 会议论文 OAI收割
10th World Congress on Intelligent Control and Automation, WCICA 2012, July 6, 2012 - July 8, 2012, Beijing, China
作者: Wang Z.; Li Y.; Li Y.; Li Y.; Li Y.

收藏 | 浏览/下载：28/0 | 提交时间：2013/03/25

In this paper the mathematical modeling and the application of a new trajectory tracking control technique for hydraulic-driven rigid-flexible manipulator are concerned. To get a closer dynamic behavior of the real system both the flexible manipulator linkage and the actuator dynamics are considered. The exact dynamic model of flexible manipulator is derived using Lagrange principle and assumed modes method. The partial decoupled dynamic equation is derived using nonlinear decoupling feedback control method. The whole dynamic model is established by a driven Jacobin matrix which represents the coupling between hydraulic servo system and mechanical system. A variable structure controller with inverse dynamics is designed for trajectory tracking. To weaken the chattering of control signal saturation function is used to instead of sign function. The experimental results investigate the effectiveness of the proposed approaches. 2012 IEEE.

The analyze and design of focusing system for space camera (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Electrical Insulating Materials and Electrical Engineering, EIMEE 2012, May 25, 2012 - May 27, 2012, Shenyang, Liaoning, China
作者: Yu T.

收藏 | 浏览/下载：29/0 | 提交时间：2013/03/25

In order to control the focal plane and guarantee the imaging quality of space camera the focusing system was proposed. Firstly the reasons of defocusing were analyzed and a solution method was given. Secondly the system structure and operating principle were introduced. Thirdly the system design was presented in detail. Finally the system was experimented. Experimental results indicate that the defocusing amount of camera can be controlled below 10 um and the focusing system satisfies the requirement of system design. (2012) Trans Tech Publications Switzerland.

Design of a miniature axial flux flywheel motor with PCB winding for nanosatellites (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Optoelectronics and Microelectronics, ICOM 2012, August 23, 2012 - August 25, 2012, Changchun, China
Wu J.

收藏 | 浏览/下载：42/0 | 提交时间：2013/03/25

This paper presents the design and analysis of an axial flux permanent-magnet (AFPM) machine for nanosatellites application. It is a miniature axial flux surface mounted permanent magnet flywheel motor using a printed circuit board (PCB) stator winding. The PCB stator has simplified the design and construction and avoids unnecessary space since size reduction has become one of the most important aspects of flywheel motor design for nanosatellites. The performances of the machine are estimated by combination method of three-dimensional (3D) electromagnetic finite element analysis (FEA) and approximate theoretical analysis. The back EMF and electromagnetic torque are derived. A comparison between the analysis and experimental measurement results of the prototype machine is also presented. Both simulated and experimental results show that the proposed motor would be an acceptable solution for the nanosatellite applications with advantages such as simple structure and low-cost as multi-layer circuit board production techniques have made the production of printed circuit coils cheaper and easier. 2012 IEEE.

Image quality assessment based on gradient complex matrix (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Systems and Informatics, ICSAI 2012, May 19, 2012 - May 20, 2012, Yantai, China
作者: Wang Y.; Wang Y.; Wang Y.; Wang Y.; Wang Y.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

An image quality assessment model based on gradient complex matrix is proposed. The vertical and horizontal gradient information of grayscale image is calculated. Complex number is used to construct the measuring matrix. Singular value decomposition is performed in order to obtain the main structure information of the image. The singular value feature vectors of the image gradient complex matrices corresponding to the reference image and the distorted image are used to measure the structural similarity of the two images. PSNR is taken as a tool to evaluate the gradient distribution similarity. Their properties are analyzed by using LIVE database and nonlinearity regression function. 2012 IEEE.