Polymer origami: programming the folding with shape

e-Polymers ◽  
2014 ◽  
Vol 14 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Leonid Ionov

AbstractThe design of three-dimensional (3D) microstructures is an interesting, fascinating and highly challenging research topic. One of the very promising approaches for 3D microstructuring, inspired by the Japanese art of paper folding – origami, is based on self-folding films. Such films consist of two kinds of materials with different volume expansion properties and are able to form different structures ranging from simple tubes to highly complex 3D shapes. In this review, our recent progress in the design of polymer bilayers and understanding of their folding is summarized.

Detection and reorganization of text may save a lot of time while reproducing old books text and its chapters. This is really challenging research topic as different books may have different font types and styles. The digital books and eBooks reading habit is increasing day by day and new documents are producing every day. So in order to boost the process the text reorganization using digital image processing techniques can be used. This research work is using hybrid algorithms and morphological algorithms. For sample we have taken an letter pad where the text and images are separated using algorithms. The another objective of this research is to increase the accuracy of recognized text and produce accurate results. This research worked on two different concepts, first is concept of Pixel-level thresholding processing and another one is Otsu Method thresholding.


2020 ◽  
Vol 6 (1) ◽  
pp. 403-416
Author(s):  
Valentina Cantone ◽  
Rita Deiana ◽  
Alberta Silvestri ◽  
Ivana Angelini

AbstractPliny the Elder testifies that roman workshops used volcanic glass (obsidian), but also produced and used a dark glass (obsidian-like glass) quite similar to the natural one. In the context of the study on medieval mosaics, the use of the obsidian and obsidian-like tesserae is a challenging research topic. In this paper, we present the results of a multidisciplinary study carried out on the Dedication wall mosaic, realized by a byzantine workshop in the 12th century in the Church of St. Mary of the Admiral in Palermo, and where numerous black-appearing tesserae, supposed to be composed of obsidian by naked-eyes observation, are present. Historical documents, multispectral imaging of the wall mosaic, and some analytical methods (SEM-EDS and XRPD) applied to a sample of black tesserae, concur in identifying here the presence of obsidian and different obsidian-like glass tesserae. This evidence, although related to the apparent tampering and restoration, could open a new scenario in the use of obsidian and obsidian-like glass tesserae during the Byzantine period in Sicily and in the reconstruction of multiple restoration phases carried out between 12th and 20th century AD on the mosaics of St. Mary of the Admiral.


2021 ◽  
Author(s):  
Jun Guo ◽  
Yutian Qin ◽  
Yanfei Zhu ◽  
Xiaofei Zhang ◽  
Chang Long ◽  
...  

Selective organic transformations using metal–organic frameworks (MOFs) and MOF-based heterogeneous catalysts have been an intriguing but challenging research topic in both the chemistry and materials communities.


2021 ◽  
Vol 1036 ◽  
pp. 35-44
Author(s):  
Ling Fang Ruan ◽  
Jia Wei Wang ◽  
Shao Ming Ying

Silicon-based anode materials have been widely discussed by researchers because of its high theoretical capacity, abundant resources and low working voltage platform,which has been considered to be the most promising anode materials for lithium-ion batteries. However,there are some problems existing in the silicon-based anode materials greatly limit its wide application: during the process of charge/discharge, the materials are prone to about 300% volume expansion, which will resultin huge stress-strain and crushing or collapse on the anods; in the process of lithium removal, there is some reaction between active material and current collector, which creat an increase in the thickness of the solid phase electrolytic layer(SEI film); during charging and discharging, with the increase of cycle times, cracks will appear on the surface of silicon-based anode materials, which will cause the batteries life to decline. In order to solve these problems, firstly, we summarize the design of porous structure of nanometer sized silicon-based materials and focus on the construction of three-dimensional structural silicon-based materials, which using natural biomass, nanoporous carbon and metal organic framework as structural template. The three-dimensional structure not only increases the channel of lithium-ion intercalation and the rate of ion intercalation, but also makes the structure more stable than one-dimensional or two-dimensional. Secondly, the Si/C composite, SiOx composite and alloying treatment can improve the volume expansion effection, increase the rate of lithium-ion deblocking and optimize the electrochemical performance of the material. The composite materials are usually coated with elastic conductive materials on the surface to reduce the stress, increase the conductivity and improve the electrochemical performance. Finally, the future research direction of silicon-based anode materials is prospected.


Author(s):  
Jianwu Lin ◽  
Mengwei Tang ◽  
Jiachang Wang ◽  
Ping He

With Private Funds having a new type of license for asset allocation practice in China, comprehensive asset allocation cross private equity and stock market has received more attention. However, most of the studies focus more on the stock market, and asset allocation models for private equity market that are mainly made based on experience. Thus, the joint allocation of assets crosses both markets making it a challenging research topic. This paper introduces the Black–Litterman model into the private equity market, realizing the transition from qualitative models to quantitative models. It lays a solid quantitative ground for the mixed asset allocation model in both the markets.


Author(s):  
Henrik Ueberschär

This survey article deals with a delta potential—also known as a point scatterer—on flat two- and three-dimensional tori. We introduce the main conjectures regarding the spectral and wave function statistics of this model in the so-called weak and strong coupling regimes. We report on recent progress as well as a number of open problems in this field.


Entropy ◽  
2019 ◽  
Vol 21 (5) ◽  
pp. 449 ◽  
Author(s):  
Xian-Qin Ma ◽  
Chong-Chong Yu ◽  
Xiu-Xin Chen ◽  
Lan Zhou

Person re-identification in the image processing domain has been a challenging research topic due to the influence of pedestrian posture, background, lighting, and other factors. In this paper, the method of harsh learning is applied in person re-identification, and we propose a person re-identification method based on deep hash learning. By improving the conventional method, the method proposed in this paper uses an easy-to-optimize shallow convolutional neural network to learn the inherent implicit relationship of the image and then extracts the deep features of the image. Then, a hash layer with three-step calculation is incorporated in the fully connected layer of the network. The hash function is learned and mapped into a hash code through the connection between the network layers. The generation of the hash code satisfies the requirements that minimize the error of the sum of quantization loss and Softmax regression cross-entropy loss, which achieve the end-to-end generation of hash code in the network. After obtaining the hash code through the network, the distance between the pedestrian image hash code to be retrieved and the pedestrian image hash code library is calculated to implement the person re-identification. Experiments conducted on multiple standard datasets show that our deep hashing network achieves the comparable performances and outperforms other hashing methods with large margins on Rank-1 and mAP value identification rates in pedestrian re-identification. Besides, our method is predominant in the efficiency of training and retrieval in contrast to other pedestrian re-identification algorithms.


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