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  • 1
    Online Resource
    Online Resource
    An Unexpected Iron (II)-Based Homogeneous Catalytic System for Highly Efficient CO2-to-CO Conversion under Visible-Light Irradiation
    MDPI AG ; 2019
    In:  Molecules Vol. 24, No. 10 ( 2019-05-16), p. 1878-
    Details
    In: Molecules, MDPI AG, Vol. 24, No. 10 ( 2019-05-16), p. 1878-
    Abstract: We present two as-synthesized Fe(II)-based molecular catalysts with 1,10-phenanthroline (phen) ligands; Fe(phen)3Cl2 (1) and [Fe(phen)2(CH3CH2OH)Cl]Cl (2), and their robust catalytic properties for the conversion of CO2 to CO in DMF/TEOA (DMF = N,N’-dimethylformamide; TEOA = triethanolamine) solution containing Ru(bpy)32+ and BIH (1,3-dimethyl-2-phenyl-2,3- dihydro-1H-benzo-[d] -imidazole). High turnover numbers (TONs) of 19,376 were achieved with turnover frequencies (TOFs) of 3.07 s−1 for complex 1 (1.5 × 10−7 M). A quantum efficiency of 0.38% was observed after 5 h irradiated by 450 nm monochromatic light. The generation rate of CO2 and H2 were tuned by optimizing the experimental conditions, resulting in a high CO selectivity of 90%. The remarkable contribution of the photosensitizer to the total TONCO was found being 19.2% (as shown by tests under similar conditions without catalysts) when BIH was employed as a sacrificial electron donor. The product selectivity in complex 2 reached 95%, and the corresponding TONCO and TOFCO were 33,167 and 4.61 s−1 in the same concentration with complex 1 used as catalyst; respectively. This work provides guidance for future designs of simple, highly efficient and selective molecular catalytic systems that facilitate carbon-neutral solar-to-fuel conversion processes
    Type of Medium: Online Resource
    ISSN: 1420-3049
    URL: Article
    DOI: 10.3390/molecules24101878
    Language: English
    Publisher: MDPI AG
    Publication Date: 2019
    detail.hit.zdb_id: 2008644-1
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  • 2
    Online Resource
    Online Resource
    Analysis and Management of Motor Failures of Hexacopter in Hover
    MDPI AG ; 2021
    In:  Actuators Vol. 10, No. 3 ( 2021-03-02), p. 48-
    Details
    In: Actuators, MDPI AG, Vol. 10, No. 3 ( 2021-03-02), p. 48-
    Abstract: This research presents an analysis and management strategy for hovering hexacopter with one or more failing motors. Of late, multirotor drones have become particularly popular, and all drones have been increasing in popularity. Unlike a fixed-wing drone, failure of motors in a multirotor craft may cause safety problems. Numerous published articles have proposed solving this problem by redesigning the control law or control gain. This approach, however, is difficult to implement because change of control gain usually involves connecting external devices. This paper proposes to keep the control gain unchanged but reallocate the thrusts. Simulations are conducted on a hexacopter in various hovering modes. Some hovering state problems are investigated for the linearized dynamics but also numerically verified for the original nonlinear dynamics. In case some motors of a hexacopter fail in flight, an allocation matrix is proposed to redistribute required thrusts to functional motors. Seven cases of motor failure are studied. This paper analytically proves that limited controllability for emergency landing is feasible in four scenarios at the linear level, but the other three scenarios are completely uncontrollable. Numerical simulations are presented to demonstrate the validity of our algorithm. An online video of real flight also confirms our results. This paper potentially helps the design of failure management of rotors and increases the successful rate of emergent landing.
    Type of Medium: Online Resource
    ISSN: 2076-0825
    URL: Article
    DOI: 10.3390/act10030048
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2682469-3
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  • 3
    Online Resource
    Online Resource
    A Sensing Element Based on a Bent and Elongated Grooved Polymer Optical Fiber
    MDPI AG ; 2012
    In:  Sensors Vol. 12, No. 6 ( 2012-06-01), p. 7485-7495
    Details
    In: Sensors, MDPI AG, Vol. 12, No. 6 ( 2012-06-01), p. 7485-7495
    Type of Medium: Online Resource
    ISSN: 1424-8220
    URL: Article
    DOI: 10.3390/s120607485
    Language: English
    Publisher: MDPI AG
    Publication Date: 2012
    detail.hit.zdb_id: 2052857-7
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  • 4
    Online Resource
    Online Resource
    Pathology, Enzyme Activity and Immune Responses after Cryptocaryon irritans Infection of Golden Pompano Trachinotus ovatus (Linnaeus 1758)
    MDPI AG ; 2023
    In:  Journal of Marine Science and Engineering Vol. 11, No. 2 ( 2023-01-23), p. 262-
    Details
    In: Journal of Marine Science and Engineering, MDPI AG, Vol. 11, No. 2 ( 2023-01-23), p. 262-
    Abstract: Golden pompano (Trachinotus ovatus) has become an economically important fish in China in the past decade. However, Cryptocaryon irritans, a parasitic ciliate, causes considerable economic losses in the mariculture of T. ovatus. To characterize the pathogenesis of C. irritans in T. ovatus, the pathological properties, immune-related enzyme activity and expression of the NEMO gene was analysed. The results from the histological sections showed that there was considerable metamorphosis and hyperplasia in the parasitized sites (skin) with leukocyte aggregation and mucous cell increases after C. irritans infection. Moreover, the activities of four enzymes, that is, alkaline phosphatase (AKP), acid phosphatase (ACP), superoxide dismutase (SOD) and lysozyme (LZM), were significantly increased in different tissues after C. irritans infection. Furthermore, the ORF of T. ovatus NF-kappa-B essential modulator (ToNEMO) measures 1650 bp, encoding 548 amino acids. The ToNEMO transcripts were universally expressed in all examined tissues, with higher levels being observed in the immune-relevant and central nervous tissues. The mRNA levels of ToNEMO after C. irritans infection were significantly increased in the gill, skin, liver, spleen and head kidney. These results suggested that ToNEMO might be involved in immune responses and helped to elucidate the physiological response after the C. irritans infection of fish.
    Type of Medium: Online Resource
    ISSN: 2077-1312
    URL: Article
    DOI: 10.3390/jmse11020262
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2738390-8
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  • 5
    Online Resource
    Online Resource
    Traceability of Geographical Origin in Gentiana straminea by UPLC-Q Exactive Mass and Multivariate Analyses
    MDPI AG ; 2019
    In:  Molecules Vol. 24, No. 24 ( 2019-12-06), p. 4478-
    Details
    In: Molecules, MDPI AG, Vol. 24, No. 24 ( 2019-12-06), p. 4478-
    Abstract: The root of Gentiana straminea Maxim. (Gentianaceae), is officially listed as “Qin-Jiao” in the Chinese Pharmacopoeia for the treatment of rheumatic arthritis, icteric hepatitis, constipation, pain, and hypertension. To establish the geographical origin traceability in G. straminea, its chemical profiles were determined by a UPLC-Q exactive mass spectrometer, from which 43 compounds were identified by comparing retention times and mass spectrometry. Meanwhile, a pair of isomers (loganin and secologanol) was identified by mass spectrometry based on their fragmentation pathway. A total of 42 samples from difference habitats were determined by an UPLC-Q exactive mass spectrometer and the data were assayed with multivariate statistical analysis. Eight characteristic compounds were identified to determine the geographical origin of the herb. To estimate the key characteristic markers associated with pharmacological function, the inhibiting activities of nitric oxide (NO) production in lipopolysaccharide (LPS)-induced macrophages were examined. This finding is crucial in realizing the determination of botanical origin and evaluating the quality of G. straminea.
    Type of Medium: Online Resource
    ISSN: 1420-3049
    URL: Article
    DOI: 10.3390/molecules24244478
    Language: English
    Publisher: MDPI AG
    Publication Date: 2019
    detail.hit.zdb_id: 2008644-1
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  • 6
    Online Resource
    Online Resource
    Electrodeposition of a Li-Al Layered Double Hydroxide (LDH) on a Ball-like Aluminum Lathe Waste Strips in Structured Catalytic Applications: Preparation and Characterization of Ni-Based LDH Catalysts for Hydrogen Evolution
    MDPI AG ; 2022
    In:  Catalysts Vol. 12, No. 5 ( 2022-05-05), p. 520-
    Details
    In: Catalysts, MDPI AG, Vol. 12, No. 5 ( 2022-05-05), p. 520-
    Abstract: A functionally structured catalyst was explored for ethanol steam reforming (ESR) to generate H2. Aluminum lathe waste strips were employed as the structured catalytic framework. The mixed metal oxide (Li-Al-O) was formed on the surface of Al lathe waste strips through calcination of the Li-Al-CO3 layered double hydroxide (LDH), working as the support for the formation of Ni catalyst nanoparticles. NaOH and NaHCO3 titration solutions were, respectively, used for adjusting the pH of the NiCl2 aqueous solutions at 50 °C when developing the precursors of the Ni-based catalysts forming in-situ on the Li-Al-O oxide support. The Ni precursor on the Al structured framework was reduced in a H2 atmosphere at 500 °C for 3 h, changing the hydroxide precursor into Ni nanoparticles. The titration agent (NaOH or NaHCO3) effectively affected the physical and chemical characterizations of the catalyst obtained by the different titrations. The ESR reaction catalyzed by the structured catalysts at a relatively low temperature of 500 °C was studied. The catalyst using NaHCO3 titration presented good stability for generating H2 during ESR, achieving a high rate of H2 volume of about 122.9 L/(gcat·h). It also had a relatively low acidity on the surface of the Li-Al-O oxide support, leading to low activity for the dehydration of ethanol and high activity to H2 yield. The interactions of catalysts between the Ni precursors and the Li-Al-O oxide supports were discussed in the processes of the H2 reduction and the ESR reaction. Mechanisms of carbon formation during the ESR were proposed by the catalysts using NaOH and NaHCO3 titration agents.
    Type of Medium: Online Resource
    ISSN: 2073-4344
    URL: Article
    DOI: 10.3390/catal12050520
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2662126-5
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  • 7
    Online Resource
    Online Resource
    Characterization of Nano-Scale Hydroxyapatite Coating Synthesized from Eggshells Through Hydrothermal Reaction on Commercially Pure Titanium
    MDPI AG ; 2020
    In:  Coatings Vol. 10, No. 2 ( 2020-01-28), p. 112-
    Details
    In: Coatings, MDPI AG, Vol. 10, No. 2 ( 2020-01-28), p. 112-
    Abstract: Commercially pure titanium (c.p. Ti) is often used in biomedical implants, but its surface cannot usually combine with the living bone. A coating of hydroxyapatite (HA) on the surface of titanium implants provides excellent mechanical properties and has good biological activity and biocompatibility. For optimal osteocompatibility, the structure, size, and composition of HA crystals should be closer to those of biological apatite. Our results show that the surface of c.p. Ti was entirely covered by rod-like HA nanoparticles after alkali treatment and subsequent hydrothermal treatment at 150 °C for 48 h. Nano-sized apatite aggregates began to nucleate on HA-coated c.p. Ti surfaces after immersion in simulated body fluid (SBF) for 6 h, while no obvious precipitation was found on the uncoated sample. Higher apatite-forming ability (bioactivity) could be acquired by the samples after HA coating. The HA coating featured bone-like nanostructure, high crystallinity, and carbonate substitution. It can be expected that HA coatings synthesized from eggshells on c.p. Ti through a hydrothermal reaction could be used in dental implant applications in the future.
    Type of Medium: Online Resource
    ISSN: 2079-6412
    URL: Article
    DOI: 10.3390/coatings10020112
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2662314-6
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  • 8
    Online Resource
    Online Resource
    Microstructure and Mechanical Properties of Galvanized-45 Steel/AZ91D Bimetallic Material by Liquid-Solid Compound Casting
    MDPI AG ; 2019
    In:  Materials Vol. 12, No. 10 ( 2019-05-21), p. 1651-
    Details
    In: Materials, MDPI AG, Vol. 12, No. 10 ( 2019-05-21), p. 1651-
    Abstract: A connection between hot-dip galvanized 45 steel and AZ91D was achieved by liquid-solid compound casting to achieve one material with a better mechanical performance and a light weight. The microstructure and properties of galvanized-steel/AZ91D bimetallic materials were investigated in this study. A scanning electron microscopy (SEM), an energy dispersive spectroscopy (EDS), and an X-ray diffraction (XRD) were applied to analyze the microstructure evolution and formation mechanism of the galvanized 45 steel/AZ91D interface zone which could be divided into three layers. Among three different layers, the layer close to AZ91D was composed of α-Mg and an eutectic structure (α-Mg + MgZn). The intermediate layer was comprised of an eutectic structure (α-Mg + MgZn), and the layer adjacent to 45 steel consisted of α-Mg and FeAl3. Furthermore, galvanized-45 steel/AZ91D bimetallic material had better shear strength than the bare-45 steel/AZ91D metallic material which can indicate that owing to the formation of metallurgical bonding, the adhesive strength of galvanized-steel and AZ91D was improved to 11.81 MPa. In addition, the fact that corrosion potential increased from −1.493 V to −1.143 V and corrosion current density changed from 3.015 × 10−5 A/cm2 to 1.34 × 10−7 A/cm2 implied that the corrosion resistance of galvanized-steel/AZ91D was much better than AZ91D.
    Type of Medium: Online Resource
    ISSN: 1996-1944
    URL: Article
    DOI: 10.3390/ma12101651
    Language: English
    Publisher: MDPI AG
    Publication Date: 2019
    detail.hit.zdb_id: 2487261-1
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  • 9
    Online Resource
    Online Resource
    Assessing the Effects of Gamification on Enhancing Information Security Awareness Knowledge
    MDPI AG ; 2021
    In:  Applied Sciences Vol. 11, No. 19 ( 2021-10-08), p. 9266-
    Details
    In: Applied Sciences, MDPI AG, Vol. 11, No. 19 ( 2021-10-08), p. 9266-
    Abstract: Information security awareness (ISA) has become a vital issue, as security breaches often attributed to humans lead to losses for individuals and organizations. Information security (IS) education may be an effective strategy to improve students’ ISA; however, studies associated with the relationships between teaching effects and information security learning are few. This study adopted gamification practice and examined its effect on students’ ISA knowledge enhancement, attitude and intention of security compliance, and willingness for continuous IS education. This study also examined the gender difference in a gamified learning system. One hundred ten undergraduates participated in a quasi-experimental study. The results indicated that students within a gamified class performed better than students within a lecture-based instructional group. We found significant gamification effects on the three security focus areas of password management, Internet use, and information handling. Gamification did not significantly impact the attitude and intention of participants’ security compliance and students’ willingness for continuous IS learning. Gender difference in the effect of gamification on ISA knowledge enhancement was not observed as well. The research provides theoretical and practical contributions by incorporating gamification into IS learning and suggests gamification as an effective means to enhance students’ knowledge acquisition in an engaging, timely, economical, and repeated manner.
    Type of Medium: Online Resource
    ISSN: 2076-3417
    URL: Article
    DOI: 10.3390/app11199266
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2704225-X
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  • 10
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    Online Resource
    Effect of Adding Waste Polyethylene and GGBFS on the Engineering Properties of Cement Mortar
    MDPI AG ; 2022
    In:  Applied Sciences Vol. 12, No. 24 ( 2022-12-10), p. 12665-
    Details
    In: Applied Sciences, MDPI AG, Vol. 12, No. 24 ( 2022-12-10), p. 12665-
    Abstract: The recycling of waste materials has become an important topic worldwide. Wastes can be effectively used in concrete to improve its characteristics. This study aimed to research cement mortar’s physical properties, mechanical properties, and durability. In a cement mortar with a fixed water-to-binder ratio (W/B) of 0.5, waste polyethylene (PE) was added at sand volume ratios of 0%, 1%, 2%, 3%, and 4%. Cement was replaced with 0%, 10%, and 20% ground granulated blast furnace slag (GGBFS). The results showed that the slump and flow of mortar tended to decline as the added amount of waste PE increased, but they also increased with the increased replaced amount of GGBFS. The setting time of mortar was shortened as the waste PE increased but delayed as the amount of GGBFS increased. In terms of mechanical properties, the compressive strength of mortar declined as the replaced amount of waste PE increased. Using the GGBFS to replace part of the cement can improve the later mortar strength. This study found that when the added waste PE was within 2% and the replacement amount of GGBFS was 10%, the goal of recycling waste was reached most effectively, while maintaining the concrete’s mechanical properties.
    Type of Medium: Online Resource
    ISSN: 2076-3417
    URL: Article
    DOI: 10.3390/app122412665
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2704225-X
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