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Preparation and excellent adsorption of water pollution dyes over magnetic Fe3O4/c nanoparticles with hollow grape cluster morphology

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JOURNAL OF NANOPARTIcLE RESEARcH 2020年第7期22卷 1-11页

作者： Wang, Junhong Zhang, Qiang Liu, Junhai Ji, Xiaohui Ma, Jianyi Tian, Guanghui Shaanxi Univ Technol Shaanxi Key Lab Catalysis Coll Chem & Environm Sci Hanzhong 723000 Peoples R China

Magnetic Fe3O4/c nanoparticles with hollow grape cluster morphology were synthesized through hydrothermal method, using SBA-15 as the hard template, glucose as the carbon source, and ferric chloride hexahydrate as the iron source. As-synthesized magnetic nanomaterials were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N(2)adsorption-desorption isotherms, vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. Meanwhile, the adsorption of organic dyes in water by magnetic nanoparticles was further studied. Results indicated that these magnetic nanomaterials exhibited hollow spherical structure similar to a bunch of grapes, and that magnetite Fe(3)O(4)particles were embedded in the matrix of carbon nanoscale. The specific surface area, pore volume, pore diameter, and saturation magnetization of prepared samples were 522.7 m(2)/g, 0.4454 cm(3)/g, 3.5 nm, and 31.9 emu/g, respectively. At the same time, as-synthesized materials presented excellent adsorption properties and reutilization, so the total adsorption capacities for methyl orange, methylene blue, and rhodamine B were as high as 400 mg/g, 600 mg/g, and 150 mg/g under the natural pH of solution, respectively. Therefore, it is anticipated that these hollow magnetic Fe3O4/c nanoparticles will have potential industrial application prospects in environment water purification.

关键词： Hollow nanoparticle Magnetism Fe3O4 c Adsorption Water treatment

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Effect of initial density on thermal conductivity of new micro-pipeline heat conduction c/Sic composites

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JOURNAL OF THE AMERIcAN cERAMIc SOcIETY 2021年第1期104卷 645-653页

作者： Zhang, Yunhai Liu, Yongsheng cao, Yejie cao, Liyang Wang, Jing Pan, Yu Wang, Ning Northwestern Polytech Univ Sci & Technol Thermostruct Composite Mat Lab Xian 710072 Peoples R China Natl Univ Def Technol Coll Aerosp Sci & Engn Sci & Technol Scramjet Lab Changsha 410073 Peoples R China

c/Sic composites prepared by chemical vapor infiltration technique (cVI) have been regarded as thermal structural materials widely. However, these composites still suffer from poor functional properties like low thermal conductivity, especially in thickness direction of the composites, limiting their large-scale applications. Herein, mesophase pitch based carbon fiber (MPcF) and continuous wave laser machining were utilized to construct highly effective heat conductive micro-pipelines within cVI c/Sic composite. The effect of initial density on the final density and thermal conductivity of the as-obtained MPcF-c/Sic composites were investigated. The results revealed that higher initial density would directly enhance the thermal conductivity and reduce the negative impact of the bottle-neck effect. At temperatures between 100 degrees c and 500 degrees c, MPcF-c/Sic composites preserved more than threefold of the thermal conductivity (340%) when compared to reference c/Sic composites. This work provides a highly effective route for enhancing the thermal conductivity of c/Sic, which would broaden their future applications.

关键词： c Sic composites heat conductive micro-pipelines initial density thermal conductivity

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comparative toxicity of a food additive TiO2, a bulk TiO2, and a nano-sized P25 to a model organism the nematode c-elegans

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ENVIRONMENTAL ScIENcE AND POLLUTION RESEARcH 2019年第4期26卷 3556-3568页

作者： Ma, Hongbo Lenz, Kade A. Gao, Xianfeng Li, Shibin Wallis, Lindsay K. Univ Wisconsin Joseph J Zilber Sch Publ Hlth Milwaukee WI 53201 USA Univ Wisconsin Dept Mat Sci & Engn Milwaukee WI 53201 USA US EPA Midcontinent Ecol Div Duluth MN USA

To help fill the knowledge gap regarding the potential human health impacts of food pigment TiO2, a comparative toxicity study was performed on a food-grade TiO2 (f-TiO2), a bulk TiO2 (b-TiO2), and a nano-sized TiO2 (Degussa P25), and in the nematode caenorhabditis elegans. Acute phototoxicity and chronic toxicity effects including reproduction, lifespan, and vulval integrity were evaluated. The f-TiO2, b-TiO2, and P25 had a primary particle size (size range) of 149 (53-308) nm, 129 (64-259) nm, and 26 (11-52) nm, respectively. P25 showed the greatest phototoxicity with a 24-h Lc50 of 6.0mg/L (95% cI 5.95, 6.3), followed by the f-TiO2 (Lc50=6.55mg/L (95% cI 6.35, 6.75)), and b-TiO2 was the least toxic. All three TiO2 (1-10mg/L) induced concentration-dependent effects on the worm's reproduction, with a reduction in brood size by 8.5 to 34%. They all caused a reduction of worm lifespan, accompanied by an increased frequency of age-associated vulval integrity defects (Avid). The impact on lifespan and Avid phenotype was more notable for P25 than the f-TiO2 or b-TiO2. Ingestion and accumulation of TiO2 particles in the worm intestine was observed for all three materials by light microscopy. These findings demonstrate that the food pigment TiO2 induces toxicity effects in the worm and further studies are needed to elucidate the human health implication of such toxicities.

关键词： Food additive TiO2 Toxicity c elegans Vulval integrity

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Ablation behavior of thin-blade co-deposited c/cx-Sicy composites under the influence of the complex fluid conditions of the oxyacetylene torch

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cERAMIcS INTERNATIONAL 2022年第12期48卷 16923-16932页

作者： Liu, Ningkun Guo, Lingjun Kou, Gang Li, Yunyu Yin, Xuemin Northwestern Polytech Univ Shaanxi Key Lab Fiber Reinforced Light Composite M Xian 710072 Peoples R China

This paper offers a new way of testing the ablation property of material under an oxyacetylene torch using a thinblade specimen, which costs much less time to reach the maximum temperature and provides a harsh turbulence fluid field that's closer to reality. The thin-blade specimen experiences a higher turbulent intensity than the traditional disk-like specimen, leading to more efficient heat exchange. The fluid field simulation agrees with the testing results. In addition, we manage to synthesize the c/cx-Sicy composites with the co-deposition chemical vapor infiltration (cVI) method. The c/cx-Sicy composites exhibit a similar anti-ablation property as c/c composites and consist of enough Sic phase simultaneously, combining the advantages of both c/c composites and c/Sic composites. The thin-blade c/cx-Sicy composites show a lower linear ablation rate (1.6 mu m/s) than c/ c composites (4.1 mu m/s) and c/Sic composites (19.6 mu m/s) during the oxyacetylene test. The glass layer formed on the surface of c/cx-Sicy could cling to the bulk material instead of peeling off due to the high Pyc content in the matrix could protect the SiO2 from blowing away.

关键词： Ablation Antioxidation c c composites Thin blade computational fluid dynamics

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On the security of biquadratic c public-key cryptosystems and its generalizations

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cRYPTOGRAPHY AND cOMMUNIcATIONS-DIScRETE-STRUcTURES BOOLEAN FUNcTIONS AND SEQUENcES 2019年第3期11卷 427-442页

作者： Felke, Patrick Univ Appl Sci Emden Leer Constantiapl 4 D-26723 Emden Germany

Public key cryptosystems based on multivariate polynomials have been studied since the eighties. One of them, called c, was introduced in 1988 by Imai and Matsumoto, and broken in 1993 by Dobbertin in classified work he did for the German Federal Office for Information Security and later by Patarin (see Dobbertin et al. 2005, Patarin 1995). Since then, the construction of multivariate systems sharing a great deal of the c properties have become of particular interest. Dobbertin introduced in a series of classified papers and later in a challenge of the MysteryTwister-competition hosted by the Horst-Gortz-Institute in 2005, (see Dobbertin et al. 2005) together with the author, a system where the central mapping is a power mapping of degree 4 and shares almost all the properties of c. It was therefore called biquadratic c. The challenge remained unbroken and the security of these systems an open problem. As its key size is rather large, the interest in such systems became low during the last years. Due to the initiative of the European Telecommunications Standards Institute and the National Institute for Standards and Technology in creating standards for post-quantum cryptography, systems with bigger key sizes have become of interest for practical applications. In this paper we will consider biquadratic c and more general systems based on hidden monomials of degree k called k-ary c. We will prove a lower bound for the running time of attacks based on Grobner basis algorithms like F-4 or F-5. We will compute the first fall degree for k-ary c and give a counterexample to the first fall degree assumption. We will derive an estimate for the complexity of breaking the above mentioned cryptochallenge and give parameter sizes for secure systems by taking into account all known types of attacks. It will turn out that the security requirements yield systems with impractical key sizes even for applications in post-quantum cryptography. Although k-ary c is not of practical inter

关键词： biquadratic c c First fall degree Degree of regularity Solving equations Grobner basis attacks Post-quantum cryptography Multivariate cryptography Dobbertin Imai-Matsumoto

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Influence of silicon infiltration on the wear and oxidation resistance of hot-pressed B4c/c(graphite) composites

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cERAMIcS INTERNATIONAL 2021年第24期47卷 34927-34939页

作者： Jiang, Tao Han, Manman Fu, Jia Xian Shiyou Univ Sch Mat Sci & Engn Xian 710065 Shaanxi Peoples R China

B4c/c(graphite) composites were produced using Hot-pressing. However, the composites exhibited low surface hardness, low wear resistance as well as low oxidation resistance. The hot-pressed B4c/c(graphite) composites were processed via silicon infiltration procedure at 1550 degrees c for 2 h in the vacuum condition to refine the wear resistance, surface hardness, and oxidation resistance of the B4c/c(graphite) composites. The silicon infiltration process resulted in the fabrication of a surface layer based on silicon carbide and silicon upon the B4c/c (graphite) composites surface. The surface layer of the silicon infiltrated B4c/c(graphite) composites, primarily comprising silicon carbide and silicon, was examined for its phase composition and microstructure. The oxidation resistance, wear resistance, and surface hardness of B4c/c(graphite) composites subjected to silicon infiltration was additionally examined. The XRD results confirmed that silicon carbide and silicon-based layer existed on the surface of B4c/c(graphite) composites, which was produced as a result of the silicon infiltration process. The surface of silicon infiltrated B4c/c(graphite) composites exhibited a 300-400 mu m thick covering of silicon carbide and silicon. The deposited layer also exhibited a dense and compact microstructure. When compared to hot-pressed B4c/c(graphite) composites, the surface hardness and wear resistance of the composites resulting after silicon infiltration were significantly enhanced. Silicon infiltrated B4c/c(graphite) composites possess a surface hardness of 16-17 GPa. The oxidation resistance of the silicon infiltrated B4c/c(graphite) composites was considerably enhanced as compared to the hot-pressed B4c/c(graphite) composites. So the silicon infiltrated B4c/c(graphite) composites exhibited high surface hardness, excellent wear resistance and excellent oxidation resistance in comparison with the hot-pressed B4c/c(graphite) composites.

关键词： A Hot pressing B composites c Hardness Wear resistance

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Behavior of a Single Bubble in a Nonuniform D.c. Electric Field

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cHEMIcAL ENGINEERING cOMMUNIcATIONS 2010年第1期198卷 19-32页

作者： Jalaal, M. Khorshidi, B. Esmaeilzadeh, E. Mohammadi, F. Univ Tabriz Fluid Mech Res Lab Fac Mech Engn Tabriz Iran Ryerson Univ Dept Elect & Comp Engn Toronto ON Canada

The effects of a nonuniform electric field on the formation, detachment, and breakup of a single inert bubble surrounded by a dielectric liquid were studied experimentally and numerically. In experiments, air bubbles were injected into kerosene at a constant flow rate through an orifice at the bottom wall of the test cell. The liquid was subjected to a nonuniform electric field, applied between the horizontal and vertical electrodes. During the experiments, the behavior of bubbles was recorded continuously, and the position, shape, and volume departure of the bubbles were digitally extracted from the sequential frames with the aid of graphical software. The experimental results show that in the presence of the nonuniform electric field, bubbles take a prolate shape and skew to the opposite direction of the ground electrode. With an increase in the electric potential, the bubble growth time and departure volume will decrease continuously. Bubble breakup is also observed at high enough voltages. As a further study, a 3-D numerical simulation was performed, using a commercial finite element code (comsol Multiphysics) to determine the distribution of electric stresses along the bubble surface. The numerical results show that the nonuniform electric field generates some inhomogeneous stresses at the bubble surface. The bubble is compressed and deviated by the horizontal component and elongated by the vertical component. Numerical outcomes prove the physical behavior of the bubble observed in the experiments.

关键词： Breakup D c electric field Electrohydrodynamic (EHD) Single bubble

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MicroRNA-135a Modulates Hepatitis c Virus Genome Replication through Downregulation of Host Antiviral Factors

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Virologica Sinica 2019年第2期34卷 197-210页

作者： catherine Sodroski Brianna Lowey Laura Hertz T.Jake Liang Qisheng Li Liver Diseases Branch National Institute of Diabetes and Digestive and Kidney Diseases National Institutes of Health

cellular microRNAs(miRNAs) have been shown to modulate HcV infection via directly acting on the viral genome or indirectly through targeting the virus-associated host factors. Recently we generated a comprehensive map of HcV–miRNA interactions through genome-wide miRNA functional screens and transcriptomics analyses. Many previously unappreciated cellular miRNAs were identified to be involved in HcV infection, including miR-135a, a human cancerrelated miRNA. In the present study, we investigated the role of miR-135a in regulating HcV life cycle and showed that it preferentially enhances viral genome replication. Bioinformatics-based integrative analyses and subsequent functional assays revealed three antiviral host factors, including receptor interacting serine/threonine kinase 2(RIPK2), myeloid differentiation primary response 88(MYD88), and c-X-c motif chemokine ligand 12(cXcL12), as bona fide targets of miR-135a. These genes have been shown to inhibit HcV infection at the RNA replication stage. Our data demonstrated that repression of key host restriction factors mediated the proviral effect of miR-135a on HcV propagation. In addition,miR-135a hepatic abundance is upregulated by HcV infection in both cultured hepatocytes and human liver, likely mediating a more favorable environment for viral replication and possibly contributing to HcV-induced liver *** results provide novel insights into HcV–host interactions and unveil molecular pathways linking miRNA biology to HcV pathogenesis.

关键词： Hepatitis c virus (HcV) Genome replication Virus-host interactions miR-135a Antiviral factors

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Analysis of a c. elegans lifespan prediction method based on a bimodal neural network and uncertainty estimation

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cOMPUTATIONAL AND STRUcTURAL BIOTEcHNOLOGY JOURNAL 2023年 21卷 655-664页

作者： Garcia-Garvi, Antonio Layana-castro, Pablo E. Sanchez-Salmeron, Antonio-Jose Univ Politecn Valencia Inst Automat Informat Ind Camino Vera S-N Valencia 46022 Spain

In recent decades, assays with the nematode caenorhabditis elegans (c. elegans) have enabled great advances to be made in research on aging. However, performing these assays manually is a laborious task. To solve this problem, numerous c. elegans assay automation techniques are being developed to increase throughput and accuracy. In this paper, a method for predicting the lifespan of c. elegans nematodes using a bimodal neural network is proposed and analyzed. Specifically, the model uses the sequence of images and the count of live c. elegans up to the current day to predict the lifespan curve termination. This network has been trained using a simulator to avoid the labeling costs of training such a model. In addition, a method for estimating the uncertainty of the model predictions has been proposed. Using this uncertainty, a criterion has been analyzed to decide at what point the assay could be halted and the user could rely on the model's predictions. The method has been analyzed and validated using real experiments. The results show that uncertainty is reduced from the mean lifespan and that most of the predictions obtained do not present statistically significant differences with respect to the curves obtained manually.(c) 2022 The Authors. Published by Elsevier B.V. on behalf of Research Network of computational and Structural Biotechnology. This is an open access article under the cc BY license (http://***/licenses/by/4.0/).

关键词： c elegans Lifespan prediction Deep learning Synthetic data Multimodal neural network

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Stochastic fatigue life prediction in c/Sic composites at elevated temperature by micromechanics-based damage model

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PROcEEDINGS OF THE INSTITUTION OF MEcHANIcAL ENGINEERS PART L-JOURNAL OF MATERIALS-DESIGN AND APPLIcATIONS 2022年第9期236卷 1699-1714页

作者： Li, Longbiao Nanjing Univ Aeronaut & Astronaut Coll Civil Aviat 29 Jiangjun Ave Nanjing 211106 Peoples R China

In this paper, a micromechanical approach is developed to predict the fatigue life and fracture process in different c/Sic composites subjected to different stochastic fatigue loading spectrums at elevated temperatures. Three types of stochastic fatigue load spectrums are considered in the fatigue life prediction at elevated temperature, that is, constant, increasing, and decreasing stochastic stress with cycles. Stress distribution between intact and broken fibers and the broken fibers fraction under stochastic fatigue loading spectrum are determined using the Global Load Sharing criterion considering multiple fatigue damage mechanisms at elevated temperatures. A new damage parameter of fatigue life degradation rate is developed to characterize the effect of stochastic loading on fatigue damage and fracture in c/Sic composites. Relationships between stochastic fatigue loading spectrum, broken fibers fraction, fatigue life, and fatigue life degradation rate in different c/Sic composite are established. Effects of stochastic fatigue loading spectrum type, stress level, and testing temperature on fatigue life degradation rate are discussed. The fatigue life degradation rate is very sensitive to the fiber preform, loading sequence, and testing temperature.

关键词： ceramic-matrix composites (cMcs) c Sic fatigue life S - N curves stochastic fatigue load spectrum micromechanical

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