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Structural optimization of patient-specific temporomandibular joint replacement implants for additive manufacturing:novel metrics for safety evaluation and biomechanical performance

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Bio-Design and Manufacturing 2022年第2期5卷 333-347页

作者： Manuel Pinheiro Anouar krairi Robin Willaert Maria c.costa Wim Van Paepegem Mechanics of Materials and Structures(MMS) Ghent UniversityGhentBelgium Materials Innovation Institute(M2i) DelftThe Netherlands Department of Oral and Maxillofacial Surgery University Hospitals Leuven LeuvenBelgium 4 Department of Head and Neck SurgeryGhent University HospitalGhentBelgium

Total temporomandibular joint(TMJ)replacement is recommended only when there is irreversible damage to the joint and no conservative treatment can provide functional *** stock and custom-made TMJ implants have been made available;however,retrospective and comparative studies were unable to find significant differences between the two types of *** introduction of additive manufacturing(AM)techniques in medical practice allows for a greater freedom of design and a higher degree of device *** combination of AM with structural optimisation may streamline development and provide the key for fabricating biomechanic ally enhanced TMJ *** this study,structural optimis ation techniques were applied to develop and numerically validate a patient-specific TMJ *** biomechanical behaviour of each intermediate TMJ design was assessed under four different nominal and maximum biting tasks using finite element *** addition,a new set of metrics were proposed to compare each design regarding biomechanical performance and implant *** results suggest that 55-82%of the natural/intact strain patterns can be recovered with the finally selected TMJ *** represents an increase of 15%in biomechanical performance for incisor biting,15%for right molar biting,17%for left molar biting and a decrease of 2%for left group biting compared with the initial *** results also suggest that load transfer at the proximal ramus reduces the implant’s impact on the mandible’s strain ***,structural optimisation allows for a volume reduction of up to 44%with a minimum loss of implant safety and biomechanical performance.

关键词： Temporomandibular joint Additive manufacturing Implant safety Biomechanical performance Finite element analysis

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Unravelling the competitive effect of microstructural features on the fracture toughness and tensile properties of near beta titanium alloys

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Journal of Materials Science & Technology 2022年第2期97卷 101-112页

作者： Yang Liu Samuel c.V.Lim chen Ding Aijun Huang Matthew Weyland Department of Materials Science and Engineering Monash UniversityClaytonVIC3800Australia Monash centre for Additive Manufacturing Monash UniversityNotting HillVIC3168Australia BAOWU Special Metallurgy co.Ltd. Shanghai200940China Monash centre for Electron Microscopy Monash UniversityClaytonVIC3800Australia

The competitive effect of microstructural features including primaryα(α_(p)),secondaryα(α_(s)),grain boundaryα(α_(GB)) and β grain size on mechanical properties of a near β Ti alloy were studied with two heat treatment *** relative effect of β grain size and STA(solution treatment and ageing)processing parameters on mechanical properties were quantitatively explored by the application of Taguchi *** results were further explained via correlating microstructure with the fracture toughness and tensile *** was found that large numbers of fine as precipitates and continuous α_(s) played greater roles than other features,resulting in a high strength and very low ductility(cess *** β grain size had a negative correlation with fracture *** the samples prepared by BAScA( β anneal slow cooling and ageing)process,improved ductility and fracture toughness were obtained due to a lower density ofα;precipitates,a basket-weave structure and zigzag morphology of α_(GB).For this heat treatment,an increase in prior β grain size had an observable positive effect on fracture *** contradictory effect of β grain size on fracture toughness found in literature was for the first time *** was shown that the microstructure obtained from different processes after β solution has complex effect on mechanical *** complexity derived from the competition between microstructure features and the overall sum of their effect on fracture toughness and tensile properties.A novel table was proposed to quasi-quantitatively unravel these competitive effects.

关键词： Nearβtitanium alloys Microstructural features competitive effect Fracture toughness βgrain size effect

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Numerical modelling of a low power non-transferred arc plasma reactor for methane conversion

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Plasma Science and Technology 2019年第6期21卷 29-37页

作者： B I MIN D k DINH D H LEE T H kIM S cHOI Institute for Nuclear Science and Technology Jeju National University 102 Jejudaehak-ro Jeju 63243Republic of Korea University of Science and Technology(UST) 217 Gajeong-ro Yuseong-gu Daejeon 34113 Republic of Korea korea Institute of Machinery and Materials 156 Gajeongbuk-ro Yuseong-gu Daejeon 34103 Republic of Korea Department of Nuclear and Energy Engineering Jeju National University 102 Jejudaehak-ro Jeju 63243Republic of Korea

Thermal flow characteristics and the methane conversion reaction in a low power arc plasma reactor for efficient storage and transport of methane,which is the main component of shale gas,were *** temperature and velocity distributions were calculated according to the type of discharge gases and arc current level by a self-developed magnetohydrodynamics (MHD)code and a commercial ANSYS-FLUENT code;the transport of chemical species was analyzed as including the chemical reactions of methane *** simulated results were verified by the comparison of calculated and measured arc voltages with permissible low error as under 4%.Three c2 hydrocarbon gases with ethane (c2H6),ethylene (c2H4),and acetylene (c2H2)were selected as the converted species of methane from experimental *** mass fraction of c2 hydrocarbons and hydrogen as the product of the conversion reaction at the reactor was also *** values show good agreement with the actual experimental results in that the major conversion reaction occurred in c2H2 and hydrogen,and the conversions to c2H6,c2H4,and hydrogen were minor reactions of methane pyrolysis conversion.

关键词： numerical modelling non-transferred arc plasma methane chemical reaction

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Hidden-symmetry-enforced nexus points of nodal lines in layer-stacked dielectric photonic crystals

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Light(Science & Applications) 2020年第1期9卷 315-324页

作者： Zhongfei Xiong Ruo-Yang Zhang Rui Yu c.T.chan Yuntian chen School of Optical and Electronic Information Huazhong University of Science and TechnologyWuhan 430074China Department of Physics The Hong Kong University of Science and TechnologyClear Water BayHong KongChina School of Physics and Technology Wuhan UniversityWuhan 430072China Wuhan National Laboratory of Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China

It was recently demonstrated that the connectivities of bands emerging from zero frequency in dielectric photonic crystals are distinct from their electronic counterparts with the same space *** discover that in an AB-layerstacked photonic crystal composed of anisotropic dielectrics,the unique photonic band connectivity leads to a new kind of symmetry-enforced triply degenerate points at the nexuses of two nodal rings and a kramers-like nodal *** emergence and intersection of the line nodes are guaranteed by a generalized 1/4-period screw rotation symmetry of Maxwell’s *** bands with a constant kz and iso-frequency surfaces near a nexus point both disperse as a spin-1 Dirac-like cone,giving rise to exotic transport features of light at the nexus *** show that spin-1 conical diffraction occurs at the nexus point,which can be used to manipulate the charges of optical *** work reveals that Maxwell’s equations can have hidden symmetries induced by the fractional periodicity of the material tensor components and hence paves the way to finding novel topological nodal structures unique to photonic systems.

关键词： symmetry nodal dielectric

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Optical and electrical characterizations of nanoparticle cu_2S thin films

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chinese Physics B 2014年第4期23卷 476-481页

作者： M.Saadeldin H.S.Soliman H.A.M.Ali k.Sawaby Physics Department Faculty of Science Cairo University Physics Department Faculty of Education Ain-Shams University

copper sulfide thin films are deposited onto different substrates at room temperature using the thermal evaporation technique. X-ray diffraction spectra show that the film has an orthorhombicchalcocite （7-cu2S） phase. The atomic force microscopy images indicate that the film exhibits nanoparticles with an average size of nearly 44 nm. Specrtophotometric measurements for the transmittance and reflectance are carried out at normal incidence in a spectral wavelength range of 450 nm-2500 nm. The refractive index, n, as well as the absorption index, k is calculated. Some dispersion parameters are determined. The analyses of el and e2 reveal several absorption peaks. The analysis of the spectral behavior of the absorption coefficient, c~, in the absorption region reveals direct and indirect allowed transitions. The dark electrical resistivity is studied as a function of film thickness and temperature. Tellier＇s model is adopted for determining the mean free path and bulk resistance.

关键词： physical properties of cu2S thermal evaporation nanoparticle cu2S thin films

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Antioxidants in Food and chronic Degenerative Diseases

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Biomedical and Environmental Sciences 1996年第2期9卷 117-123页

作者： J．k．cANDLISH N．P．DAS BiochemistryDepartment NationalUniversityofSingaporeKentRidgeCrescentSingapore0511 BiochemistryDepa

Both preventive and chain breaking antioxidants have a role in the limitation of free radical damage. Some of these may be regarded as 'classical', like vitamins E and c but others are more recently discovered, such as the flavonoids, widespread in plant tissues, and the muscle constituents anserine and carnosine. The major conditions in which the role of antioxidants is under intense investigation include coronary artery disease, cancer and diabetes. There are theoretical underpinnings for the efficacy of antioxidants in each of these, with the protection of low density lipoprotein (in respect of the first) being exceptionally *** attention is now being focussed on the flavonoids, which are surprisingly pleiotropic in their effects. For one of them, quercetin, over a dozen seemingly independent biologica1 effects can be listed, including the inhibition of low density lipoprotein *** also inhibit peroxidation in foodstuffs, as opposed to *** is much controversy over antioxidant supplementation policies, some authorities recommending a massive programme of supplementation for all ages and classes, others stressing the value of the traditional mixed diet. This matter is unlikely to be resolved soon,but in the meantime sensible supplementation policies should be continued for those most vulnerable, that is, babies and the aged

关键词：食物成分抗氧化剂慢性退行性疾病自由基损伤

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comparative Study of Physical Properties of Polymer composites Reinforced with Uncarbonised and carbonised coir

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Open Journal of Polymer chemistry 2014年第3期4卷 73-82页

作者： F. O. Aguele c. I. Madufor k. F. Adekunle chemical Engineering Department Michael Okpara University of Agriculture Umudike Nigeria Polymer and Textile Engineering Department Federal University of Technology Owerri Nigeria

This study involved the use of uncarbonised and carbonised coir in preparing composites of a given polymer. In this case natural rubber (NR) was used. Uncarbonised coir (Uc) and carbonised coir (cc) were separately used to prepare the polymer composites. carbon black (cB) was also used differently and the filler loadings for all varied between 0 and 50 phr. Before using the uncarbonised coir and carbonised coir, they were characterised on the basis of moisture content, pH, particles size and surface area. The properties of the various composite samples prepared were then investigated. The results of the tests obtained for the NR-Uc composites were compared with those of NR-cc and also with those of NR-cB composites. It was observed that for hardness, the results obtained from composites of Uc and cc fillers showed similar trends with those of carbon black (cB) reinforced composites, increasing with increase in filler volume. For the tensile strength and modulus a trend of slight rise was observed. There were no sharp rises in values as filler volumes were increased. Uc and cc fillers were observed to impart very poorly on the tensile strength and modulus relative to the cB reinforced composites. The results from test for elongation, compression set and flex fatigue showed a falling trend for all the fillers to a comparable level with cB. It was generally observed that the uncarbonised coir presented better potentials for reinforcement than the carbonised coir.

关键词： Polymer composites Reinforcing Fillers coir and Vulcanisation

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Origin of Red color of the Lower Siwalik Palaeosols:A Micromorphological Approach

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Journal of Mountain Science 2009年第2期6卷 147-154页

作者： Seema Singh B.Parkash Arun.k.Awasthi Department of Earth Sciences Indian Institute of Technology RoorkeeRoorkee-247667 India Department of Earth Sciences Indian Institute of Technology RoorkeeRoorkee–247667 India

Palaeosols associated with fluvial of the Siwalik Group are and lacustrine deposits that occur as thick multiple pedocomplexes. The bright red color of the palaeosol beds has been earlier interpreted as a result of hot and arid palaeoclimate. However, as against this view, our investigations of the bright red palaeosol beds of the Lower Siwaliks suggest that the climate was cool and subhumid, instead of hot and arid during the deposition of these beds. Since cold climate is not very conducive to impart red coloration, further research is needed to explain the cause of these red beds. For this, the micromorphological study of soil thin sections was done which showed the presence of features such as dissolution and recrystallisation of quartz, feldspar and mica, compaction, slickensides, presence of calcite spars, subrounded and cracked nature of quartz grains, microfabric, complex patterns of birefringence fabrics, pigmentary ferric oxides, thick cutans and cementation by calcite. These features indicate that diagenesis took place on a large scale in these sediments. The positive Eh and neutral-alkaline pH of soils also suggest that the conditions were favorable for the formation of diagenetic red beds. During burial diagenesis of sediments, the hydroxides of ferromagnesian minerals got converted into ferric oxide minerals （hematite）. During deep burial diagenesis smectite was converted into illite and the preponderance of illite over smectite with increasing depth of burial also indicates the diagenesis of sediments. Thus, the red color of the Lower Siwalik palaeosols seems to be due mainly to the burial diagenesis of sediments and does not appear to be due to the then prevailing climatic condition.

关键词： Palaeosols c3 type vegetation diagenetic red beds calcite spars

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Development of thermophysical calculator for stainless steel casting alloys by using cALPHAD approach

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china Foundry 2017年第5期14卷 353-358页

作者： In-Sung cho k.D.Savelyev V.M.Golod korea Institute of lndustrial Technology Korea Peter the Great St.Petersburg Polytechnic University Russia

The calculation of thermophysical properties of stainless steel castings and its application to casting simulation is discussed. It is considered that accurate thermophysical properties of the casting alloys are necessary for the valid simulation of the casting processes. Although previous thermophysical calculation software requires a specific knowledge of thermodynamics, the calculation method proposed in the present study does not require any special knowledge of thermodynamics, but only the information of compositions of the alloy. The proposed calculator is based on the cALPHAD approach for modeling of multi-component alloys, especially in stainless steels. The calculator proposed in the present study can calculate thermophysical properties of eight-component systems on an iron base alloy(Fe-c-Si-cr-Mn-Ni-cu-Mo), and several korean standard stainless steel alloys were calculated and discussed. The calculator can evaluate the thermophysical properties of the alloys such as density, heat capacity, enthalpy, latent heat, etc, based on full Gibbs energy for each phase. It is expected the proposed method can help casting experts to devise the casting design and its process easily in the field of not only stainless steels but also other alloy systems such as aluminum, copper, zinc, etc.

关键词： stainless steels casting simulation thermophysical properties cALPHAD

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Inhibition of African swine fever virus in liquid and feed by medium-chain fatty acids and glycerol monolaurate

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Journal of Animal Science and Biotechnology 2021年第2期12卷 569-578页

作者： Joshua A.Jackman Astghik Hakobyan Hovakim Zakaryan charles c.Elrod School of chemical Engineering Sungkyunkwan UniversitySuwon 16419Republic of Korea Group of Antiviral Defense Mechanisms Institute of Molecular Biology of NASYerevanArmenia Natural Biologics Inc. NewfieldNY 14867USA. Department of Animal Science Cornell UniversityIthacaNY 14853USA

Background:The ongoing African swine fever virus(ASFv)epidemic has had a major impact on pig production globally and biosecurity efforts to curb ASFv infectivity and transmission are a high *** has been recently identified that feed and feed ingredients,along with drinking water,can serve as transmission vehicles and might facilitate transboundary spread of ***,it is important to test the antiviral activity of regulatory compatible,antiviral feed additives that might inhibit ASFv infectivity in *** promising group of feed additive candidates includes medium-chain fatty acids(McFA)and monoglyceride derivatives,which are known to disrupt the lipid membrane surrounding certain enveloped viruses and ***:The antiviral activities of selected McFA,namely caprylic,capric,and lauric acids,and a related monoglyceride,glycerol monolaurate(GML),to inhibit ASFv in liquid and feed conditions were investigated and suitable compounds and inclusion rates were identified that might be useful for mitigating ASFv in feed *** assays showed that all tested McFA and GML inhibit *** was more potent than McFA because it worked at a lower concentration and inhibited ASFv due to direct virucidal activity along with one or more other antiviral ***-dependent feed experiments further showed that sufficiently high GML doses can significantly reduce ASFv infectivity in feed in a linear manner in periods as short as 30 min,as determined by infectious viral titer ***-linked immunosorbent assay(ELISA)experiments revealed that GML treatment also hinders antibody recognition of the membrane-associated ASFv p72 structural protein,which likely relates to protein conformational changes arising from viral membrane ***:Together,the findings in this study indicate that McFA and GML inhibit ASFv in liquid conditions and that GML is also able to reduce ASFv infectivity in feed,which may help to curb disease tr

关键词： African swine fever virus Antiviral Feed pathogen mitigation McFA Medium-chain fatty acids Monoglycerides

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