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Analysis of factors affecting diagonal tension and compression capacity of corner joints in furniture frames fabricated with dovetail key

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Journal of Forestry Research 2013年第1期24卷 155-168页

作者： Mosayeb Dalvand Ghanbar Ebrahimi Akbar Rostampour Haftkhani Sadegh Maleki Department of wood and Paper Science and technology Faculty of Natural ResourcesUniversity of TehranKarajIran.

This study was conducted to analyze the effect of joint type, and numbers and types of dovetail keys on diagonal tension and compression performance of corner joints in a furniture frame. Joint members were cut from white fir lumber. Butted and mitered joints were constructed with one and two dovetail key（s） with butterfly and H shapes. Joints were glued by polyvinyl acetate （PVAc） and cynoacrylate （CA）. Compression capacity of joints was higher than diagonal tension. Mitered joints were stronger than butted ones. Butterfly dovetail keys were superior to H shape keys. Double keys performed better than single key. Experimental joints glued with PVAc were stronger than those glued with CA glue and control specimens. In terms of strength, butterfly dovetailed joints were comparable with doweled joints.

关键词： diagonal tension diagonal compression dovetail key joints lumber

The Security of Using Large Language Models:A Survey With Emphasis on ChatGPT

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IEEE/CAA Journal of Automatica Sinica 2025年第1期 1-26页

作者： Wei Zhou Xiaogang Zhu Qing-Long Han Lin Li Xiao Chen Sheng Wen Yang Xiang the School of Science Computing and Engineering Technologies Swinburne University of Technology IEEE the School of Computer and Mathematical sciences the University of Adelaide Adelaide the faculty of Science and Engineering Southern Cross University the School of Information and Physical sciences the University of Newcastle

ChatGPT is a powerful artificial intelligence(AI)language model that has demonstrated significant improvements in various natural language processing(NLP) tasks. However, like any technology, it presents potential security risks that need to be carefully evaluated and addressed. In this survey, we provide an overview of the current state of research on security of using ChatGPT, with aspects of bias, disinformation, ethics, misuse,attacks and privacy. We review and discuss the literature on these topics and highlight open research questions and future *** this survey, we aim to contribute to the academic discourse on AI security, enriching the understanding of potential risks and mitigations. We anticipate that this survey will be valuable for various stakeholders involved in AI development and usage, including AI researchers, developers, policy makers, and end-users.

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Luminescence properties of calcium tungstate activated by lanthanide(Ⅲ) ions

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Journal of Rare Earths 2014年第3期32卷 221-225页

作者： Z.Piskula J.Czajka K.Staninski S.Lis faculty of Chemistry Adam Mickiewicz University faculty of Chemical technology and Engineering University of Technology and Life Sciences in Bydgoszcz

Calcium tungstate phosphors activated by the Ln3＋ ions （Ln-Pr, Nd, Tb, Yb） were synthesized by a traditional high-temperature solid-state method. The crystal structures and morphologies of the products were characterized by scanning electron microscopy （SEM）, X-ray powders diffraction （XRD） and infrared spectra （FT-1R）. The samples were fotmd to show luminescence properties （down-conversion, DC, at excitation wavelength 254 nm and up-conversion, UC, at excitation wavelength 980 nm）. CaWO4 doped with Tb3＋/yb3＋ showed green DC and UC luminescence characteristic of Tb（Ⅲ） ion in the range of 470-660 nm, cor- responding to the 5D4→7F6,5,4,3,2 electronic transition. CaWO4 doped with Pr3＋/Yb3＋ showed week blue, green and red （DC and UC） luminescence of Pr（Ⅲ） ion, in the wavelength region of 450-700 nm. Emission peaks were ascribed to the 3P1→3H4,5,6, 3P0→3H4,5,6, 3P1→3F2 and 3P0→3F2 transitions, respectively. CaWO4 doped with Nd3＋/yb3＋ phosphor emitted orange UC luminescence at 450-690 nm （2p3/2→4I15/2, 4G7/2→419/2,11/2,13/2） and strong near-infrared UC luminescence at 720-900 nm （4F7/2＋4S3/2→4419/2, 4F5/2＋2H3/2→419/2, 4F3/2→4I9/2） which is the characteristic of Nd（Ⅲ） ion.

关键词： lanthanides calcium tungstate up-conversion luminescence rare earths

EFFECT OF ARTIFICIAL WEATHERING AND TEMPERATURE CYCLING ON THE ADHESION STRENGTH OF WATERBORNE ACRYLATE COATING SYSTEMS USED FOR woodEN WINDOWS

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Journal of Green Building 2020年第1期15卷 3-14页

作者： Šimůnková Kristýna Hýsek Štěpán Oberhofnerová Eliška Pánek Miloš Fidan Hakan faculty of Forestry and wood sciences Czech University of Life Sciences in PragueKamycka 129Prague 16500Czech Republic

The adhesion of coatings to wood is important for their long-term *** this study,the adhesion strength of water-based acrylate coatings used for wooden windows after exposure to artificial weathering(AW)and temperature cycling(TC)was *** analysis of the adhesion quality of coatings was performed via a pull-off test and failure *** 3-layered and 4-layered white and brown acrylate dispersions from six different producers were compared and the effect of coating thickness on adhesion strength was *** adhesion strength values proved to be very *** AW,the adhesion strength and its variability increased for all the *** had no statistically significant effect on the adhesion strength *** coating systems were initially characterized by lower adhesion strength,but after AW and TC,they reached higher adhesion strength values than brown *** overall highest adhesion after AW and TC was recorded for the coatings based on alkyd-acrylate hybrid basis(Producer 3),while the lowest adhesion variability after AW was measured for one type of tested acrylate coating(Producer 4).The effect of different layering on adhesion strength was not demonstrated in this study.

关键词： acrylate coatings adhesion strength artificial weathering coating thickness pull-off test temperature cycling

Classification of Teleparallel Homothetic Vector Fields in Cylindrically Symmetric Static Space-Times in Teleparallel Theory of Gravitation

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Communications in Theoretical Physics 2010年第10期54卷 675-678页

作者： Ghulam Shabbir Suhail Khan faculty of Engineering sciences GIK Institute of Engineering Sciences and Technology

In this paper we classify cylindrically symmetric static space-times according to their teleparallel homothetic vector fields using direct integration technique. It turns out that the dimensions of the teleparallel homothetic vector fields are 4, 5, 7 or 11, which are the same in numbers as in general relativity. In case of 4, 5 or 7 proper teleparallel homothetic vector fields exist for the special choice to the space-times. In the case of 11 teleparallel homothetic vector fields the space-time becomes Minkowski with all the zero torsion components. Teleparallel homothetic vector fields in this case are exactly the same as in general relativity. It is important to note that this classification also covers the plane symmetric static space-times.

关键词： teleparallel homothetic vector fields WeitzenbSck connections torsion

Deadwood position matters:Diversity and biomass of saproxylic beetles in a temperate beech forest

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Forest Ecosystems 2024年第1期11卷 120-130页

作者： Vaclav Zumr Oto Nakladal Josef Gallo JiríRemes faculty of Forestry and wood sciences Czech University of Life Sciences PragueKamýck a 129Praha 6-Suchdol16500Czech Republic

Deadwood plays a key role for biodiversity in forests.A significant number of beetles from this group are currently listed as endangered in the Red *** addition to other management recommendations,there have been recent efforts to enrich stands with dead wood to promote *** important parameter for forestry enterprises is the optimization of these *** study investigated the abundance,species richness,gamma diversity,conservation value and biomass of saproxylic beetles in natural forests using window traps.A total of 89traps were used for saproxylic beetle monitoring,of which 29 were placed on lying logs,30 on snags and 30 as controls in forest stand space.A total of 35,011 beetles were recorded in 564 species(61 families).Notably,20,515 of these belong to saproxylic beetles(59%)in 311 species(55%),with 62 classified as Red-List species(20%).In the group of'all saproxylic beetles',the results indicate that a diversity and y diversity(q=0)remain consistent across various deadwood types,whileβdiversity showed significant *** differences were found in the Red-List species group,where a diversity and y diversity differed,with higher values observed in *** based total species richness of site was estimated to be 391 species,including 74 Red-Listed *** the sample coverage of the studied stand categories showed that all saproxylic species exhibit a pronounced preference for inhabiting areas featuring lying ***,Red-List species mainly inhabit snags,withβdiversity being more similar to snags and forest stand ***,both the conservation value(weighted average by conservation status)and beetle biomass are significantly highest in snags,whereas stand space shows the lowest values across all measured saproxylic beetle ***,the use of traps set on the poles in forest stand space resulted in an underestimation of the actual stand richness by 20%-25%.Our results support th

关键词： Snags Coleoptera Fagus sylvatica Unmanaged forests Red-list Coarse woody debris

Physical and mechanical properties of Klainedoxa gabonensis with engineering potential

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Journal of Forestry Research 2017年第3期28卷 629-636页

作者： K.Boakye Boadu C.Antwi-Boasiako K.Frimpong-Mensah Department of wood Science&technology Faculty of Renewable Natural ResourcesKwame Nkrumah University of Science&TechnologyKumasiGhana

Adequate information is sparse for many tropical timbers on their engineering applications, which make their international promotion difficult. The physical and mechanical properties of Klainedoxa gabonensis Pierre ex Engl. （a lesserutilized species） and Entandrophragma cylindricum were compared. K. gabonensis contained more moisture with greater density at 12 % moisture content than E. cylindricum and had a tangential-radial ratio for swelling and shrinkage of 1.31-1.38 and 1.58-1.63, respectively, within acceptable thresholds for engineering/structural timbers. For K. gabonensis, shear parallel to grain was 32.2 ± 0.4-33.5 ±1 N mm^-2; compressive parallel to grain, 80.7 ± 1.4-90.6± 1 N mm^-2; modulus of rupture, 204± 4.0-214 ± 4.0 N mm^-2 and modulus of elasticity, 28,932 ± 664-29,493 ±822 N mm^-2. These properties were superior to those of E. cylindricum [（15.5 ± 0.9）- （15.6 ± 0.6）, （56.4 ± 4.5）-（63.6 ± 1.2）, （99.4 ± 4.7）- （121.3 ± 10.6）, and （9987.4 ± 207）-（10,051 ± 258） N mm^-2, respectively] and compared well with those of several traditional timbers for conslruction and furniture production. Its use would contribute to minimize pressure on the primary timbers in the forests and widen the raw material base for wooden products.

关键词： Density Dimensional stability Timberengineering Mechanical property Tangential-radialratio Traditional timber

Organo-silane compounds in medium density fiberboard:physical and mechanical properties

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Journal of Forestry Research 2015年第2期26卷 495-500页

作者： Hamid Reza Taghiyari Ali Karimi Paridah Md.Tahir wood Science & technology Department Faculty of Civil EngineeringShahid Rajaee Teacher Training University Department of wood and Paper Science & technology Faculty of Natural ResourcesThe University of Tehran Laboratory of Biocomposite technology Institute of Tropical Forestry & Forest Products (INTROP)University Putra Malaysia (UPM)

We studied the effects of nanoparticles of organo-silane（NOS） compounds in the size range of20–80 nm on physical and mechanical properties in medium density fiberboard,and used NOS at four consumption levels of 0,50,100,and 150 g kg-1dry wood *** of all treatments was kept constant at 0.67 g *** water-repellent property of organo-silane significantly reduced water absorption（WA） and thickness swelling but mechanical properties declined due to the reduced proportion of wood-fiber as organo-silane was added to the matrix：the compression ratio of MDF panels and the integrity among wood-fibers both declined,resulting in reduced mechanical *** recommend use of 50 g of NOS/kg wood-fiber to improve WA and thickness swelling while retaining acceptable mechanical properties.

关键词： Composite-board Medium-density fiberboard(MDF) Nanotechnology Physical and mechanical properties Water-repellant Organo-silane

The diameter of beech snags is an important factor for saproxylic beetle richness: Implications for forest management and conservation

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Forest Ecosystems 2023年第5期10卷 635-645页

作者： Václav Zumr Oto Nakládal Lukás Bílek JiríRemes Czech University of Life sciences Prague Faculty of Forestry and Wood SciencesKamýcka 129Praha 6–Suchdol16500Czech Republic

Snags are an important component of beech forests that promote ***,their occurrence is completely marginal in managed *** snags in these stands would greatly enhance *** investigated whether snag dimensions were important for saproxylic beetle richness since they were easily transferable parameters to forest management and assessed the presence of other snag microhabitats affecting beetle *** collection was performed using passive flight traps placed on thirty snags in a recent beech reserve.A total of 6706 adults belonging to 231 saproxylic species(53 Red List species,23%)were *** results showed that the most important snag parameters were the diameter(thickness)and canopy openness of the surrounding *** occurrence of Fomes fomentarius,the volume of snag and decay class 3 were marginally significant in terms of the preference of all saproxylic *** diversity was reduced by an advanced degree of decay and a surprisingly deep stem *** dividing snag thickness into categories(70 cm DBH),we found that categories with snag diameter greater than 35 cm showed little differences in all saproxylic and Red List species richness and diversity indices and exhibited the highest similarity in beetle *** recommendations to forest managers in terms of optimization and simplification of practical procedures,we suggest actively creating high stumps to act as snags greater than 35 cm in DBH diameter to promote biodiversity in beech management stands.

关键词： Deadwood Coleoptera Biodiversity Active management Endangered beetles