Chung Yuan Christian University

About: Chung Yuan Christian University is a education organization based out in Taoyuan City, Taiwan. It is known for research contribution in the topics: Membrane & Fuzzy logic. The organization has 9819 authors who have published 11623 publications receiving 213139 citations. The organization is also known as: Tiong-gôan-tāi-ha̍k & CYCU.

Design of an Amphiphilic Polymer for Nanoparticle Coating and Functionalization

Abstract: Inorganic colloidal nanoparticles, such as quantum dots or Au nanoparticles, have been extensively investigated for two decades in physics as well as in chemistry. Applications in a variety of fields such as optics, electronics, and biology are envisaged and important proof-of-concept studies have been reported. In particular, with regard to biologically motivated applications, colloidal stability is a key requirement. Apart from nanoparticles stabilized with small ligand molecules, lipids, [6–8] and surface silanization, amphiphilic polymers have been also used by several groups to disperse originally hydrophobic nanoparticles in aqueous solution. This class of amphiphilic particle coatings not only enables the phase transfer of the nanoparticles from organic solvents to aqueous solution, but also serves as a versatile platform for chemical modification and bioconjugation of the particles because biological molecules can be covalently linked to the polymer surface. Because the stability of the amphiphilic coating around the nanoparticle solely depends on the hydrophobic interaction, this procedure is very general and does, for example, not depend on the material of the inorganic nanoparticle core, as it is the case for ligand exchange protocols. Because of the numerous contact points mediated by hydrophobic interaction, the attachment of the polymer to the particle surface is highly stable and can be improved further by crosslinking of the polymer shell. Nowadays quantum dots coated with amphiphilic polymers and with various biological molecules attached to their surface are commercially available (e.g., Invitrogen). The amphiphilic polymers that have been used so far for coating hydrophobic inorganic nanoparticles consist of hydrophobic side chains for the linkage to the nanoparticle surface and a hydrophilic backbone that provides water solubility through charged groups (in general -COO ) and also acts as an anchor for the attachment of biological molecules with bioconjugate chemistry. In this report, we introduce an amphiphilic polymer which involves a third kind of building block: functional organic molecules. The functional organic molecules are linked to the hydrophobic side chains in a similar way as the hydrophilic backbone and provide additional functionality in the particle surface (Figure 1). The amphiphilic polymer described here is based on a poly(maleic anhydride) backbone. Reaction of a fraction of the anhydride rings with alkylamines leads to the formation of the hydrophobic side chains that are needed for intercalation with the hydrophobic surfactant layer on the nanoparticle surface. Another fraction of the anhydride rings is used to link functional organic molecules to the backbone. Like the alkylamines, organic molecules bearing amino-groups can be directly linked to the anhydride rings by reaction of the anhydride with the amino group. In this way alkylamines and organic molecules with amino terminations can be linked to the polymer backbone in a one-pot reaction. The resulting amphiphilic polymer is then wrapped around hydrophobic capped nanoparticles and the organic solvent is replaced by aqueous solution according to our previously published procedure. By linking some of the remaining anhydride rings with diamine linkers, the polymer molecules around each nanoparticle are interconnected and, thus, the shell is crosslinked. Upon phase transfer to aqueous solution, the remaining anhydride rings open to yield negatively charged carboxyl groups, which provide electrostatic repulsion resulting in a stable dispersion of the nanoparticles. Apart from negatively charged carboxyl groups, the polymer surface of the nanoparticles also contains embedded functional organic molecules. The strategy reported here has several advantageous features: 1) The maleic anhydride moieties react spontaneously with high yield with both amino-modified hydrophobic side-chains (such as alkylamines) and functional organic molecules with amino terminal groups. 2) No additional reagents are needed for the coupling. In comparison, [*] R. A. Sperling, M. Zanella, Prof. W. J. Parak Fachbereich Physik, Philipps Universit#t Marburg Renthof 7, 35037 Marburg (Germany) E-mail: Wolfgang.Parak@physik.uni-marburg.de C.-A. J. Lin, R. A. Sperling, P.-Y. Li, M. Zanella, Prof. W. J. Parak Center for NanoScience Ludwig-Maximilians-Universit#t M8nchen Munich (Germany) C.-A. J. Lin, T.-Y. Yang, W. H. Chang Department of Biomedical Engineering Chung Yuan Christian University Taiwan (ROC) C.-A. J. Lin, J. K. Li, W. H. Chang R&D Center for Membrane Technology Center for Nano Bioengineering Chung Yuan Christian University Taiwan (ROC) [] These authors contributed equally to this work. [] Present address: Institute of Biotechnology, National Cheng Kung University, Taiwan (ROC)

Metal-Organic-Framework-Derived Hollow N-Doped Porous Carbon with Ultrahigh Concentrations of Single Zn Atoms for Efficient Carbon Dioxide Conversion.

Abstract: The development of efficient and low energy-consumption catalysts for CO2 conversion is desired, yet remains a great challenge. Herein, a class of novel hollow porous carbons (HPC), featuring well dispersed dopants of nitrogen and single Zn atoms, have been fabricated, based on the templated growth of a hollow metal-organic framework precursor, followed by pyrolysis. The optimized HPC-800 achieves efficient catalytic CO2 cycloaddition with epoxides, under light irradiation, at ambient temperature, by taking advantage of an ultrahigh loading of (11.3 wt %) single-atom Zn and uniform N active sites, high-efficiency photothermal conversion as well as the hierarchical pores in the carbon shell. As far as we know, this is the first report on the integration of the photothermal effect of carbon-based materials with single metal atoms for catalytic CO2 fixation.

CANN: An intrusion detection system based on combining cluster centers and nearest neighbors

Abstract: The aim of an intrusion detection systems (IDS) is to detect various types of malicious network traffic and computer usage, which cannot be detected by a conventional firewall. Many IDS have been developed based on machine learning techniques. Specifically, advanced detection approaches created by combining or integrating multiple learning techniques have shown better detection performance than general single learning techniques. The feature representation method is an important pattern classifier that facilitates correct classifications, however, there have been very few related studies focusing how to extract more representative features for normal connections and effective detection of attacks. This paper proposes a novel feature representation approach, namely the cluster center and nearest neighbor (CANN) approach. In this approach, two distances are measured and summed, the first one based on the distance between each data sample and its cluster center, and the second distance is between the data and its nearest neighbor in the same cluster. Then, this new and one-dimensional distance based feature is used to represent each data sample for intrusion detection by a k-Nearest Neighbor (k-NN) classifier. The experimental results based on the KDD-Cup 99 dataset show that the CANN classifier not only performs better than or similar to k-NN and support vector machines trained and tested by the original feature representation in terms of classification accuracy, detection rates, and false alarms. I also provides high computational efficiency for the time of classifier training and testing (i.e., detection).