Deep Space Universe

Liu Zheng Ran 한국콘텐츠학회 2023 ICCC International Digital Design Invitation Exhib Vol.2023 No.12

Visual Fatigue Reduction Based on Depth Adjustment for DIBR System

( Ran Liu ),( Yingchun Tan ),( Fengchun Tian ),( Hui Xie ),( Guoqin Tai ),( Weimin Tan ),( Junling Liu ),( Xiaoyan Xu ),( Chaibou Kadri ),( Naana Abakah ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.4

A depth adjustment method for visual fatigue reduction for depth-image-based rendering (DIBR) system is proposed. One important aspect of the method is that no calibration parameters are needed for adjustment. By analyzing 3D image warping, the perceived depth is expressed as a function of three adjustable parameters: virtual view number, scale factor and depth value of zero parallax setting (ZPS) plane. Adjusting these three parameters according to the proposed parameter modification algorithm when performing 3D image warping can effectively change the perceived depth of stereo pairs generated in DIBR system. As the depth adjustment is performed in simple 3D image warping equations, the proposed method is facilitative for hardware implementation. Experimental results show that the proposed depth adjustment method provides an improvement in visual comfort of stereo pairs as well as generating comfortable stereoscopic images with different perceived depths that people desire.

Applications of Bacterial Cellulose-Based Composite Materials in Hard Tissue Regenerative Medicine

Liu Yingyu,Liu Haiyan,Guo Susu,Qi Jin,Zhang Ran,Liu Xiaoming,Sun Lingxiang,Zong Mingrui,Cheng Huaiyi,Wu Xiuping,Shanxi Medical University School and Hospital of Stomatology 한국조직공학과 재생의학회 2023 조직공학과 재생의학 Vol.20 No.7

BACKGROUND: Cartilage, bone, and teeth, as the three primary hard tissues in the human body, have a significant application value in maintaining physical and mental health. Since the development of bacterial cellulose-based composite materials with excellent biomechanical strength and good biocompatibility, bacterial cellulose-based composites have been widely studied in hard tissue regenerative medicine. This paper provides an overview of the advantages of bacterial cellulose-based for hard tissue regeneration and reviews the recent progress in the preparation and research of bacterial cellulose-based composites in maxillofacial cartilage, dentistry, and bone. METHOD: A systematic review was performed by searching the PubMed and Web of Science databases using selected keywords and Medical Subject Headings search terms. RESULTS: Ideal hard tissue regenerative medicine materials should be biocompatible, biodegradable, non-toxic, easy to use, and not burdensome to the human body; In addition, they should have good plasticity and processability and can be prepared into materials of different shapes; In addition, it should have good biological activity, promoting cell proliferation and regeneration. Bacterial cellulose materials have corresponding advantages and disadvantages due to their inherent properties. However, after being combined with other materials (natural/ synthetic materials) to form composite materials, they basically meet the requirements of hard tissue regenerative medicine materials. We believe that it is worth being widely promoted in clinical applications in the future. CONCLUSION: Bacterial cellulose-based composites hold great promise for clinical applications in hard tissue engineering. However, there are still several challenges that need to be addressed. Further research is needed to incorporate multiple disciplines and advance biological tissue engineering techniques. By enhancing the adhesion of materials to osteoblasts, providing cell stress stimulation through materials, and introducing controlled release systems into matrix materials, the practical application of bacterial cellulose-based composites in clinical settings will become more feasible in the near future.

Electrochemical Formation Mechanism for the Controlled Synthesis of Heterogeneous MnO₂/Poly(3,4-ethylenedioxythiophene) Nanowires

Liu, Ran,Duay, Jonathon,Lee, Sang Bok American Chemical Society 2011 ACS NANO Vol.5 No.7

<P>The formation mechanism of a coaxial manganese oxide/poly(3,4-ethylenedioxythiophene) (MnO<SUB>2</SUB>/PEDOT) nanowire is elucidated herein by performing electrodeposition of MnO<SUB>2</SUB> and PEDOT on Au-sputtered nanoelectrodes with different shapes (ring and flat-top, respectively) within the 200 nm diameter pores of an anodized aluminum oxide (AAO) template. It is found that PEDOT prefers to grow on the sharp edge of the ring-shaped electrode, while MnO<SUB>2</SUB> is more likely to deposit on the flat-top electrode due to its smooth surface. The formation of coaxial nanowires is shown to be a result of simultaneous growth of core MnO<SUB>2</SUB> and shell PEDOT by an analysis of the current density resulting from electrochemical deposition. Furthermore, the structures of the MnO<SUB>2</SUB>/PEDOT coaxial nanowires were studied for their application as supercapacitors by modifying their coelectrodeposition potential. A potential of 0.70 V is found to be the most favorable condition for synthesis of MnO<SUB>2</SUB>/PEDOT coaxial nanowires, resulting in a high specific capacitance of 270 F/g. Additionally, other heterogeneous MnO<SUB>2</SUB>/PEDOT nanostructures are produced, such as nanowires consisting of MnO<SUB>2</SUB> nanodomes with PEDOT crowns as well as segmented MnO<SUB>2</SUB>/PEDOT nanowires. This is accomplished by simply adjusting the parameters of the electrochemical deposition. Finally, in smaller diameter (50 nm) AAO channels, MnO<SUB>2</SUB> and PEDOT are found to be partially assembled into coaxial nanowires due to the alternative depletion of Mn(II) ions and EDOT monomers in the smaller diameter pores.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2011/ancac3.2011.5.issue-7/nn201106j/production/images/medium/nn-2011-01106j_0004.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn201106j'>ACS Electronic Supporting Info</A></P>

Hole-filling Based on Disparity Map and Inpainting for Depth-Image-Based Rendering

Ran Liu,Zekun Deng,Lin Yi,Zhenwei Huang,Donghua Cao,Miao Xu,Ruishuang Jia 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.5

Due to the changes in viewpoint, holes may appear in the novel view synthesized by depth-image-based rendering (DIBR). A hole-filling method combining disparity-map-based hole-filling and inpainting is proposed. The method first eliminates matching errors in destination image according to the disparity map. Then, holes are classified into different types according to their sizes. Finally, a disparity-map-based approach and an improved exemplar-based inpainting algorithm are used to fill different types of holes according to the type of hole. Experimental results show that the artifacts at the edge of foreground objects can be reduced in synthesized view since the matching errors are eliminated before hole-filling. In addition, the proposed method can achieve more natural and satisfactory results in filled areas in comparison with the disparity-map-based approach and Gautier’s inpainting algorithm, though it may result in higher time complexity.

Redox Exchange Induced MnO₂ Nanoparticle Enrichment in Poly(3,4-ethylenedioxythiophene) Nanowires for Electrochemical Energy Storage

Liu, Ran,Duay, Jonathon,Lee, Sang Bok American Chemical Society 2010 ACS NANO Vol.4 No.7

<P>MnO<SUB>2</SUB> nanoparticle enriched poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires are fabricated by simply soaking the PEDOT nanowires in potassium permanganate (KMnO<SUB>4</SUB>) solution. The structures of these MnO<SUB>2</SUB> nanoparticle enriched PEDOT nanowires are characterized by SEM and TEM, which show that the MnO<SUB>2</SUB> nanoparticles have uniform sizes and are finely dispersed in the PEDOT matrix. The chemical constituents and bonding of these composite nanowires are characterized by energy-dispersive X-ray analysis, X-ray photoelectron spectroscopy, and infrared spectroscopy, which indicate that the formation and dispersion of these MnO<SUB>2</SUB> nanoparticles into the nanoscale pores of the PEDOT nanowires are most likely triggered by the reduction of KMnO<SUB>4</SUB> <I>via</I> the redox exchange of permanganate ions with the functional group on PEDOT. Varying the concentrations of KMnO<SUB>4</SUB> and the reaction time controls the loading amount and size of the MnO<SUB>2</SUB> nanoparticles. Cyclic voltammetry and galvanostatic charge−discharge are used to characterize the electrochemical properties of these MnO<SUB>2</SUB> nanoparticle loaded PEDOT nanowires. Due to their extremely high exposed surface area with nanosizes, the pristine MnO<SUB>2</SUB> nanoparticles in these MnO<SUB>2</SUB> nanoparticle enriched PEDOT nanowires show very high specific capacitance (410 F/g) as the supercapacitor electrode materials as well as high Li<SUP>+</SUP> storage capacity (300 mAh/g) as cathode materials of Li ion battery, which boost the energy storage capacity of PEDOT nanowires to 4 times without causing excessive volume expansion in the polymer. The highly conductive and porous PEDOT matrix facilitates fast charge/discharge of the MnO<SUB>2</SUB> nanoparticles and prevents them from agglomerating. These synergic properties enable the MnO<SUB>2</SUB> nanoparticle enriched PEDOT nanowires to be promising electrode materials for supercapacitors and lithium ion batteries.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2010/ancac3.2010.4.issue-7/nn1010182/production/images/medium/nn-2010-010182_0012.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn1010182'>ACS Electronic Supporting Info</A></P>

Discrimination of neutrons and gamma-rays in plastic scintillator based on spiking cortical model

Liu Bing-Qi,Liu Hao-Ran,Chang Lan,Cheng Yu-Xin,Zuo Zhuo,Li Peng 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.9

In this study, a spiking cortical model (SCM) based n-g discrimination method is proposed. The SCMbased algorithm is compared with three other methods, namely: (i) the pulse-coupled neural network (PCNN), (ii) the charge comparison, and (iii) the zero-crossing. The objective evaluation criteria used for the comparison are the FoM-value and the time consumption of discrimination. Experimental results demonstrated that our proposed method outperforms the other methods significantly with the highest FoM-value. Specifically, the proposed method exhibits a 34.81% improvement compared with the PCNN, a 50.29% improvement compared with the charge comparison, and a 110.02% improvement compared with the zero-crossing. Additionally, the proposed method features the second-fastest discrimination time, where it is 75.67% faster than the PCNN, 70.65% faster than the charge comparison and 38.4% slower than the zero-crossing. Our study also discusses the role and change pattern of each parameter of the SCM to guide the selection process. It concludes that the SCM's outstanding ability to recognize the dynamic information in the pulse signal, improved accuracy when compared to the PCNN, and better computational complexity enables the SCM to exhibit excellent n-g discrimination performance while consuming less time.

Hole-filling Based on Disparity Map for DIBR

( Ran Liu ),( Hui Xie ),( Fengchun Tian ),( Yingjian Wu ),( Guoqin Tai ),( Yingchun Tan ),( Weimin Tan ),( Bole Li ),( Hengxin Chen ),( Liang Ge ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.10

Due to sharp depth transition, big holes may be found in the novel view that is synthesized by depth-image-based rendering (DIBR). A hole-filling method based on disparity map is proposed. One important aspect of the method is that the disparity map of destination image is used for hole-filling, instead of the depth image of reference image. Firstly, the big hole detection based on disparity map is conducted, and the start point and the end point of the hole are recorded. Then foreground pixels and background pixels are distinguished for hole-dilating according to disparity map, so that areas with matching errors can be determined and eliminated. In addition, parallaxes of pixels in the area with holes and matching errors are changed to new values. Finally, holes are filled with background pixels from reference image according to these new parallaxes. Experimental results show that the quality of the new view after hole-filling is quite well; and geometric distortions are avoided in destination image, in contrast to the virtual view generated by depth-smoothing methods and image inpainting methods. Moreover, this method is easy for hardware implementation.

The New Strategy of Object-Based Directional Query

Run-tao liu,Yan-ming Wang,Zhen-guo Zhao,Guang -Yue Tian 보안공학연구지원센터 2014 International Journal of Database Theory and Appli Vol.7 No.6

To increase directional query efficiency, based on the study of existing algorithms of directional query, new pruning rules for directional query were given, combined with the new index structure MB-tree. The rules exclude the MBRs outside the query area and output all leaf nodes in the MBRs inside the query area. Based on the orders defined in MB-tree, a new algorithm of directional query is given combining with MB-tree by using recursive method, and the new algorithm can reduce I/O cost effectively. Experiment showed that the new directional query algorithm reduces the number of visited nodes, decreases I/O cost, and improves the efficiency of directional query.

Synthesis and characterization of RuO₂/poly(3,4-ethylenedioxythiophene) composite nanotubes for supercapacitors

Liu, Ran,Duay, Jonathon,Lane, Timothy,Bok Lee, Sang Royal Society of Chemistry 2010 Physical chemistry chemical physics Vol.12 No.17

<P>We report the synthesis of composite RuO<SUB>2</SUB>/poly(3,4-ethylenedioxythiophene) (PEDOT) nanotubes with high specific capacitance and fast charging/discharging capability as well as their potential application as electrode materials for a high-energy and high-power supercapacitor. RuO<SUB>2</SUB>/PEDOT nanotubes were synthesized in a porous alumina membrane by a step-wise electrochemical deposition method, and their structures were characterized using electron microscopy. Cyclic voltammetry was used to qualitatively characterize the capacitive properties of the composite RuO<SUB>2</SUB>/PEDOT nanotubes. Their specific capacitance, energy density and power density were evaluated by galvanostatic charge/discharge cycles at various current densities. The pseudocapacitance behavior of these composite nanotubes originates from ion diffusion during the simultaneous and parallel redox processes of RuO<SUB>2</SUB> and PEDOT. We show that the energy density (specific capacitance) of PEDOT nanotubes can be remarkably enhanced by electrodepositing RuO<SUB>2</SUB> into their porous walls and onto their rough internal surfaces. The flexible PEDOT prevents the RuO<SUB>2</SUB> from breaking and detaching from the current collector while the rigid RuO<SUB>2</SUB> keeps the PEDOT nanotubes from collapsing and aggregating. The composite RuO<SUB>2</SUB>/PEDOT nanotube can reach a high power density of 20 kW kg<SUP>−1</SUP> while maintaining 80% energy density (28 Wh kg<SUP>−1</SUP>) of its maximum value. This high power capability is attributed to the fast charge/discharge of nanotubular structures: hollow nanotubes allow counter-ions to readily penetrate into the composite material and access their internal surfaces, while a thin wall provides a short diffusion distance to facilitate ion transport. The high energy density originates from the RuO<SUB>2</SUB>, which can store high electrical/electrochemical energy intrinsically. The high specific capacitance (1217 F g<SUP>−1</SUP>) which is contributed by the RuO<SUB>2</SUB> in the composite RuO<SUB>2</SUB>/PEDOT nanotube is realized because of the high specific surface area of the nanotubular structures. Such PEDOT/RuO<SUB>2</SUB> composite nanotube materials are an ideal candidate for the development of high-energy and high-power supercapacitors.</P> <P>Graphic Abstract</P><P>RuO<SUB>2</SUB>/poly(3,4-ethylenedioxythiophene) composite nanotubes with high specific capacitance and fast charging/discharging capability for high-energy and high-power supercapacitor applications are reported. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=b918589p'> </P>