47 research outputs found

    Single-Tooth Modeling for 3D Dental Model

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    An integrated single-tooth modeling scheme is proposed for the 3D dental model acquired by optical digitizers. The cores of the modeling scheme are fusion regions extraction, single tooth shape restoration, and single tooth separation. According to the “valley” shape-like characters of the fusion regions between two adjoining teeth, the regions of the 3D dental model are analyzed and classified based on the minimum curvatures of the surface. The single tooth shape is restored according to the bioinformation along the hole boundary, which is generated after the fusion region being removed. By using the extracted boundary from the blending regions between the teeth and soft tissues as reference, the teeth can be separated from the 3D dental model one by one correctly. Experimental results show that the proposed method can achieve satisfying modeling results with high-degree approximation of the real tooth and meet the requirements of clinical oral medicine

    One-Step Preparation of High Performance TiO 2 /CNT/CQD Nanocomposites Bactericidal Coating with Ultrasonic Radiation

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    © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).As an environmental semiconductor material, TiO2 has important applications in the fields of environmental protection and water treatment. The preparation of P25 particles into nano-functional material films with a high specific surface area has always been a bottleneck limiting its large-scale application. In this paper, a one-step method of preparing TiO2 nanocomposites by doping carbon nanotube (CNT) and carbon quantum dots (CQD) with tetrabutyltitanate and P25 TiO2 under ultrasonic radiation is proposed to synthesize a novel antifouling material, which both eliminates the bacterium of Escherichia coli and shows good photoelectric properties, indicating a great value for the industrial promotion of TiO2/CNT. This mesoporous composite exhibits a high specific surface area of 78.07 M2/g (BET) and a tested pore width range within 10–120 nm. The surface morphology of this composite is characterized by TEM and the microstructure is characterized through XRD. This preparation method can fabricate P25 particles into a nano-functional material film with a high specific surface area at a very low cost.Peer reviewe

    Preparation and properties of antistatic high-strength aramid III/MWCNTs-OH fibers

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    Composite fibers made from aramid III and hydroxylated multiwalled carbon nanotubes (MWCNTs-OH) combine the excellent mechanical and electrical properties of both components, resulting in strong antistatic performance. However, it is of paramount importance to ensure the homogeneous dispersion of multi-walled carbon nanotubes functionalized with hydroxyl groups (MWCNTs-OH) within the aramid III spinning solution and optimize the compatibility between the two constituents to augment the overall performance of the composite fibers. To this end, this investigation successfully accomplished the dispersion of MWCNTs-OH in the spinning solution and probed the dispersion mechanism using molecular dynamics simulations. Moreover, composite fibers, comprising 2.4 weight percent MWCNTs-OH, were initially fabricated using the wet spinning method. These fibers displayed a uniform texture and a tensile strength of 1.210 GPa, signifying a noteworthy enhancement of 113.25% in comparison to the strength prior to modification. With respect to thermal behavior, the fibers exhibited a mass reduction of 21.24% within the temperature range of 0°C–538°C. In the temperature interval from 538°C to 800°C, the mass loss diminished to 10.31%, representing a substantial 71.03% reduction when compared to the unmodified state. Remarkably, even when subjected to temperatures exceeding 800°C, the composite fibers retained a residual mass of 68.45%, indicating a notable 61.17% increase from their initial condition. In terms of electrical properties, the fibers exhibited a specific resistance (ρ) of 3.330 × 109 Ω cm, demonstrating effective antistatic behavior. In summary, the antistatic composite fibers studied in this paper can effectively mitigate the hazards of static electricity in various applications, including military protection and engineering equipment in both military and civilian fields

    Three-Dimensional Simulation of the Shrinkage Behavior of Injection-Molded Poly Lactic Acid (PLA): Effects of Temperature, Shear Rate and Part Thickness

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    The effects of injection temperature, shear and part thickness on the linear shrinkage of injection-molded poly (lactic acid) (PLA) were intensively analyzed using the Autodesk Moldflow software. The obtained results showed that both melt temperature and shear rate had obvious effects on the linear shrinkage of PLA, i.e., the linear shrinkage of PLA increases significantly with the increase of melt temperature and shear rate. In addition, the shrinkage of high-crystallinity PLA was remarkably larger than that of low-crystallinity PLA, and thin-walled parts was larger than thick-walled ones in shrinkage

    ï»żNomenclatural and taxonomic notes on Rubus davidianus Kuntze and R. viburnifolius Franch

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    Critical examinations of specimens, with literature reviews, have shown that Rubus davidianus is conspecific with R. lambertianus. Therefore, we treat R. davidianus as a new synonym within Rubus. We propose a new name, Rubus loirensis Ti R. Huang nom. nov. to replace the later homonym of R. pycnanthus Genev. Additionally, lectotypification of three names, R. davidianus Kuntze, R. malifolius Focke and R. viburnifolius Franch., are designated here after examination of previous works

    Approaches to energy efficiency in China’s large-scale public building

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    In recent years, the energy shortage has become a barrier to social development as there is a shortage of resources, especially non-renewable resources. In order to improve the current situation of human settlement for future generations, a series of environmental protection activities and rational utilizations of natural resources have been carried out at a global level on the theme of "Sustainable Development". Along with the quantitative growth of Chinese public buildings, especially the Large-Scale Public Buildings, the levels of energy consumption are rising and this phenomenon has been seen as a key point of energy management from a national view. This paper discusses the realities of energy consumption and the energy-saving policies of public buildings in the world’s major developed countries, and sums up the current condition of Chinese energy consumption in relation to public buildings. With regard to these factors, this paper tries to find approaches for solving the existing problems in each construction section. Less developed construction technology in China leads to a waste of materials and labor force. There is a lack of professional personnel to handle the operational management and a lack of consideration for energy efficiency in the designing process. There is not a suitable framework for compiling statistics and data on energy consumption. There are still many management problems such as inadequate policy standards in operability or implementation, unclear positioning in governmental management, ineffective incentive or punitive mechanisms, and a defective state system which results directly in an undeveloped service system for energy efficiency. Based on all of the problems listed above, this paper suggests solutions in four areas, namely Policy, Energy Statistics, Management and Education, in order to give academic support for the overhaul of Large-Scale Public Buildings towards greater energy efficiency in China

    Approaches to energy efficiency in China’s large-scale public building

    No full text
    In recent years, the energy shortage has become a barrier to social development as there is a shortage of resources, especially non-renewable resources. In order to improve the current situation of human settlement for future generations, a series of environmental protection activities and rational utilizations of natural resources have been carried out at a global level on the theme of "Sustainable Development". Along with the quantitative growth of Chinese public buildings, especially the Large-Scale Public Buildings, the levels of energy consumption are rising and this phenomenon has been seen as a key point of energy management from a national view. This paper discusses the realities of energy consumption and the energy-saving policies of public buildings in the world’s major developed countries, and sums up the current condition of Chinese energy consumption in relation to public buildings. With regard to these factors, this paper tries to find approaches for solving the existing problems in each construction section. Less developed construction technology in China leads to a waste of materials and labor force. There is a lack of professional personnel to handle the operational management and a lack of consideration for energy efficiency in the designing process. There is not a suitable framework for compiling statistics and data on energy consumption. There are still many management problems such as inadequate policy standards in operability or implementation, unclear positioning in governmental management, ineffective incentive or punitive mechanisms, and a defective state system which results directly in an undeveloped service system for energy efficiency. Based on all of the problems listed above, this paper suggests solutions in four areas, namely Policy, Energy Statistics, Management and Education, in order to give academic support for the overhaul of Large-Scale Public Buildings towards greater energy efficiency in China.www.ima.kth.s

    Approaches to energy efficiency in China’s large-scale public building

    No full text
    In recent years, the energy shortage has become a barrier to social development as there is a shortage of resources, especially non-renewable resources. In order to improve the current situation of human settlement for future generations, a series of environmental protection activities and rational utilizations of natural resources have been carried out at a global level on the theme of "Sustainable Development". Along with the quantitative growth of Chinese public buildings, especially the Large-Scale Public Buildings, the levels of energy consumption are rising and this phenomenon has been seen as a key point of energy management from a national view. This paper discusses the realities of energy consumption and the energy-saving policies of public buildings in the world’s major developed countries, and sums up the current condition of Chinese energy consumption in relation to public buildings. With regard to these factors, this paper tries to find approaches for solving the existing problems in each construction section. Less developed construction technology in China leads to a waste of materials and labor force. There is a lack of professional personnel to handle the operational management and a lack of consideration for energy efficiency in the designing process. There is not a suitable framework for compiling statistics and data on energy consumption. There are still many management problems such as inadequate policy standards in operability or implementation, unclear positioning in governmental management, ineffective incentive or punitive mechanisms, and a defective state system which results directly in an undeveloped service system for energy efficiency. Based on all of the problems listed above, this paper suggests solutions in four areas, namely Policy, Energy Statistics, Management and Education, in order to give academic support for the overhaul of Large-Scale Public Buildings towards greater energy efficiency in China

    A Systematic Review of Critical Success Factors in Blended Learning

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    Against the backdrop of the post-pandemic period, there is an increasing need for blended learning in modern higher education systems. Critical success factors for blended learning should be considered as key indicators of learning outcomes. Therefore, the aim is to systematically review studies that examine the critical success factors for blended learning from the perspectives of the learner, instructor, course, design, technology, and environment. Eighty-two articles were analysed according to PRISMA (Preferred Reporting Items for Systematic Review and Meta-analysis) principles. The results show that critical success factors in these six dimensions have a positive impact on blended learning outcomes. These critical success factors are mainly learner characteristics, teacher characteristics, course materials and objectives, learning characteristics according to institutional objectives, ICT system, and learning environment. Future research could explore the impact of positive emotions on student and teacher learning outcomes in blended learning
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