Comparison of the higher diffraction order images in methyl-red-doped liquid crystal films

Dewei Gong,Zhongxiang Zhou,Chunfeng Hou,Yongyuan Jiang,Hao Tian 한국물리학회 2009 Current Applied Physics Vol.9 No.4

We investigate the change of higher diffraction order images in holographic image storage and reconstruction process. In experiments, an s-polarized Ar+ laser (488.0 nm) was used to record permanent grating in the dye-doped liquid crystal, 4,4'-n-entylcyanobiphenyl (5CB) doped with 1 wt% methyl-red (MR), at a small incident angle. Higher diffraction order images were observed when the signal beam was focused in front of and behind the film. Then the film was illuminated by an s-polarized He–Ne laser (632.8 nm) in the direction perpendicular to the surface. The higher diffraction order images were reconstructed. A theory about the change of higher diffraction order images is developed, which is in good agreement with experimental results. The results show that the higher diffraction order provides a useful method for optical information processing. We investigate the change of higher diffraction order images in holographic image storage and reconstruction process. In experiments, an s-polarized Ar+ laser (488.0 nm) was used to record permanent grating in the dye-doped liquid crystal, 4,4'-n-entylcyanobiphenyl (5CB) doped with 1 wt% methyl-red (MR), at a small incident angle. Higher diffraction order images were observed when the signal beam was focused in front of and behind the film. Then the film was illuminated by an s-polarized He–Ne laser (632.8 nm) in the direction perpendicular to the surface. The higher diffraction order images were reconstructed. A theory about the change of higher diffraction order images is developed, which is in good agreement with experimental results. The results show that the higher diffraction order provides a useful method for optical information processing.

Vegetable Production in China

Dewei Zhu,Guangshu Liu,Yufen Meng 한국원예학회 1993 한국원예학회 기타간행물 Vol.- No.-

VEGETABLE PRODUCTION IN CHINA

Zhu Dewei(朱德위),Liu Guangshu,Meng Yufen 한국원예학회 1993 한국원예학회 학술발표요지 Vol.11 No.1

Reliability analysis of load-sharing systems with memory

Wang, Dewei,Jiang, Chendi,Park, Chanseok Springer-Verlag 2019 Lifetime data analysis Vol.25 No.2

A Modular Stacked Transformer Structure for LLC Resonant Converters and Analysis of Current Sharing Behavior in Parallel PCB Windings

Jahangir Afsharian,Dewei (David) Xu,Ning Zhu,Bing Gong,Zhihua Yang 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

This paper proposes a modular stacked transformer structure for high-efficiency and high-power LLC resonant converters. Besides the benefits of shrunken footprint and shorten secondary current travelling path that were introduced by the vertically stacked structure, the specific feature of modularity design makes the transformer be simply applied to higher power ratings with high efficiency, high power density and easy fabrication. The design modularity for high power rating extension is demonstrated on a 380 V/12 V 2.4 kW LLC transformer with 4-stack winding PCBs and one core set. Current sharing behavior among all paralleled secondary windings of the proposed stacked structure and its modular design is discussed in terms of the magnetomotive force distribution. The effect of current sharing on winding losses is analyzed and verified using finite element analysis (FEA) simulation. Experimental results show that the LLC converter with the proposed 2.4 kW modular stacked transformer can achieve a peak efficiency of 98.05%.

Soluble Expression of a Human MnSOD and Hirudin Fusion Protein in Escherichia coli, and Its Effects on Metastasis and Invasion of 95-D Cells^s

( Shanze Yi ),( Dewei Niu ),( Fang Bai ),( Shuaiguang Li ),( Luyuan Huang ),( Wenyan He ),( Anand Prasad ),( Alexander Czachor ),( Lee Charles Tan ),( Narasaiah Kolliputi ),( Feng Wang ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.11

Manganese superoxide dismutase (MnSOD) is a vital enzyme that protects cells from free radicals through eliminating superoxide radicals (O^2-). Hirudin, a kind of small active peptide molecule, is one of the strongest anticoagulants that can effectively cure thrombus diseases. In this study, we fused Hirudin to the C terminus of human MnSOD with the GGGGS linker to generate a novel dual-feature fusion protein, denoted as hMnSOD-Hirudin. The hMnSOD-Hirudin gene fragment was cloned into the pET15b (SmaI, CIAP) vector, forming a recombinant pET15b-hMnSOD-Hirudin plasmid, and then was transferred into Escherichia coli strain Rosetta-gami for expression. SDS-PAGE was used to detect the fusion protein, which was expected to be about 30 kDa upon IPTG induction. Furthermore, the hMnSOD-Hirudin protein was heavily detected as a soluble form in the supernatant. The purification rate observed after Ni NTA affinity chromatography was above 95%. The hMnSOD-Hirudin protein yield reached 67.25 mg per liter of bacterial culture. The identity of the purified protein was confirmed by western blotting. The hMnSOD-Hirudin protein activity assay evinced that the antioxidation activity of the hMnSOD-Hirudin protein obtained was 2,444.0 ± 96.0 U/㎎, and the anticoagulant activity of the hMnSOD-Hirudin protein was 599.0 ± 35.0 ATU/㎎. In addition, in vitro bioactivity assay showed that the hMnSODHirudin protein had no or little cytotoxicity in H9c2, HK-2, and H9 (human CD₄ ⁺, T cell) cell lines. Transwell migration assay and invasion assay showed that the hMnSOD-Hirudin protein could suppress human lung cancer 95-D cell metastasis and invasion in vitro.

A biologically inspired model based on a multi-scale spatial representation for goal-directed navigation

( Weilong Li ),( Dewei Wu ),( Jia Du ),( Yang Zhou ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.3

Inspired by the multi-scale nature of hippocampal place cells, a biologically inspired model based on a multi-scale spatial representation for goal-directed navigation is proposed in order to achieve robotic spatial cognition and autonomous navigation. First, a map of the place cells is constructed in different scales, which is used for encoding the spatial environment. Then, the firing rate of the place cells in each layer is calculated by the Gaussian function as the input of the Q-learning process. The robot decides on its next direction for movement through several candidate actions according to the rules of action selection. After several training trials, the robot can accumulate experiential knowledge and thus learn an appropriate navigation policy to find its goal. The results in simulation show that, in contrast to the other two methods(G-Q, S-Q), the multi-scale model presented in this paper is not only in line with the multi-scale nature of place cells, but also has a faster learning potential to find the optimized path to the goal. Additionally, this method also has a good ability to complete the goal-directed navigation task in large space and in the environments with obstacles.

Commutation Compensation for Matrix based Rectifiers due to Leakage Inductances of Isolation Transformer

Tao Zhao,Jianhui Su,Dewei (David) Xu,Meiqin Mao 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

This paper proposes a compensation method for isolated matrix based rectifiers. The line side THD and output voltage isolated matrix rectifier are mainly affected by the commutation delay due to transformer leakage inductances. Since DC output voltage is usually regulated by a close loop controller. But the grid side current is affected by the commutation delay. The transformer leakage inductances increases the commutation delay which reduces actual dwell time of the active vector, causes distortion on grid side current with higher current THD. The proposed compensation method takes the commutation time into consideration and extends the dwell time for active vector properly. The algorithm has been verified by simulation results.

Recent Progress in Tungsten Oxides based Memristors and their Neuromorphological Applications

Bo Qu,Adnan Younis,Dewei Chu 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.6

The advance in conventional silicon based semiconductor industry is nowbecoming indeterminacy as it still along the road of Moore’s Law and concomitantproblems associated with it are the emergence of a number of practical issues suchas short channel effect. In terms of memory applications, it is generally believedthat transistors based memory devices will approach to their scaling limits up to2018. Therefore, one of the most prominent challenges today in semiconductorindustry is the need of a new memory technology which is able to combine the bestcharacterises of current devices. The resistive switching memories which areregarded as “memristors” thus gain great attentions thanks to their specificnonlinear electrical properties. More importantly, their behaviour resembles withthe transmission characteristic of synapse in biology. Therefore, the research ofsynapses biomimetic devices based on memristor will certainly bring a greatresearch prospect in studying synapse emulation as well as building artificialneural networks. Tungsten oxides (WOx) exhibits many essential characteristics asa great candidate for memristive devices including: accredited endurance (over 105cycles), stoichiometric flexibility, complimentary metal-oxide-semiconductor(CMOS) process compatibility and configurable properties including non-volatilerectification, memorization and learning functions. Herein, recent progress onTungsten oxide based materials and its associating memory devices had beenreviewed. The possible implementation of this material as a bio-inspired artificialsynapse is also highlighted. The penultimate section summaries the currentresearch progress for tungsten oxide based biological synapses and end up withseveral proposals that have been suggested for possible future developments.

Design of Course-Keeping Controller for a Ship Based on Backstepping and Neural Networks

Qiang ZHANG,Na JIANG,Yancai HU,Dewei PAN 국제이네비해양경제학회 2017 International Journal of e-Navigation and Maritime Vol.7 No.1

Due to the existence of uncertainties and the unknown time variant environmental disturbances for ship course nonlinear control system, the ship course adaptive neural network robust course-keeping controller is designed by combining the backstepping technique. The neural networks (NNs) are employed for the compensating of the nonlinear term of the nonlinear ship course-keeping control system. The designed adaptive laws are designed to estimate the weights of NNs and the bounds of unknown environmental disturbances. The first order commander are introduced to solve the problem of repeating differential operations in the traditional backstepping design method, which let the designed controller easier to implement in navigation practice and structure simplicity. Theoretically, it indicates that the proposed controller can track the setting course in arbitrary expected accuracy, while keeping all control signals in the ship course control closed-loop system are uniformly ultimately bounded. Finally, the training ship of Dalian Maritime University is taken for example; simulation results illustrated the effectiveness and the robustness of the proposed controller.