检索结果-南通市图书馆

Standardization in optical coating characterisation

在线全文

学校读者我要写书评

暂无评论

光学精密工程 2005年第4期13卷 435-453页

作者： d. Ristau Laser Zentrum Hannover 30419 Hannover Germany

In the rapid development course of laser technology and modern optics, optical metrology continuously gains importance for the quality management in the industrial production environment and also for research in optical coatings. Besides absorption and scatter losses, the spectral characteristics and laser induced damage thresholds are considered as common quality factors for coated optical components and often define the optimization targets for new products and applications. Also, these quality parameters are the basis for the comparison of commercial optics and can be found in the product catalogues of most manufacturers of optical components. As a consequence, standardization of characterisation procedures for these fundamental properties evolved to a crucial point for the optics industry. during the last decade, adapted standard measurement techniques have been elaborated and discussed by representatives from many industrial companies and research institutes within working groups of the International Organisation for Standardization (ISO). In this contribution, the current state of standardized characterisation techniques for optical coatings is summarised. Selected standards for the measurement of absorption (ISO 11551), scattering (ISO 13696) and laser induced damage thresholds (ISO 11254, Parts 1 and 2) will be described and discussed in view of their applicability and reproducibility. The report will be concluded by an outlook on the current projects and future tasks of standardization in optics characterisation.

关键词：光学涂覆技术激光技术光谱标准化激光仪器

Structural and mass transport properties of liquid ytterbium in the temperature range 1123 K–1473 K

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2023年第6期32卷 481-488页

作者： d d Satikunvar N K Bhatt B Y Thakore department of Physics Sardar Patel UniversityVallabh VidyanagarGujarat 388120India department of Physics Maharaja Krishnakumarsinhji Bhavnagar UniversityBhavnagarGujarat 364001India

We have studied the structural and atomic transport properties of liquid f-shell Yb in the temperature range 1123 K–1473 K. Pair interactions between atoms are derived using a local pseudopotential. The potential parameters are fitted to the phonon dispersion curve at room temperature. The local pseudopotential used in the present study is computationally more efficient with only three parameters, and it is found to be transferable to the liquid phase without changing the *** the various computed properties agree with reported theoretical and experimental findings, the adopted fitting scheme is justified. As a significant outcome of the study, we find that(i) the melting in Yb is governed by the Lindemann's law,(ii)the mass transport mechanism obeys the Arrhenius law,(iii) the role of the three-particle correlation function in deriving the velocity autocorrelation function is small,(iv) the mean-square atomic displacement is more sensitive to the choice of interaction potential than the other bulk properties, and(v) liquid Yb does not show liquid–liquid phase transition within the studied temperature range. Further, due to the good description of the structural and mass transport properties, we propose that Yb remains divalent at reduced density.

关键词： transport properties pseudopotential single-particle dynamics ytterbium

Probabilistic fragility analysis:A tool for assessing design rules of RC buildings

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2008年第1期7卷 45-56页

作者： Nikos d Lagaros Institute of Structural Analysis&Seismic Research National Technical University of AthensGreece Lecturer

In this work, fragility analysis is performed to assess two groups of reinforced concrete structures. The first group of structures is composed of buildings that implement three common design practices; namely, fully infilled, weak ground story and short columns. The three design practices are applied during the design process of a reinforced concrete building. The structures of the second group vary according to the value of the behavioral factors used to define the seismic forces as specified in design procedures. Most seismic design codes belong to the class of prescriptive procedures where if certain constraints are fulfilled, the structure is considered safe. Prescriptive design procedures express the ability of the structure to absorb energy through inelastic deformation using the behavior factor. The basic objective of this work is to assess both groups of structures with reference to the limit-state probability of exceedance. Thus, four limit state fragility curves are developed on the basis of nonlinear static analysis for both groups of structures. Moreover, the 95% confidence intervals of the fragility curves are also calculated, taking into account two types of random variables that influence structural capacity and seismic demand.

关键词： probabilistic fragility analysis design practice behavior factor Monte Carlo simulation method

Mineralization of ^(14)C-ring Labelled 2,4-d in Egyptian Soils Under Aerobic and Anaerobic Conditions

在线全文

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2002年第4期15卷 306-314页

作者： S．M．A．d．ZAYEd M．FARGHALY 等 NationalReserachCenter DokkiCairoEgypt

Obiectives To study the mineralization of 2,4-d in clay and clay loam Egyptian soils under subtropical conditions over a period of 90 d. Methods Using 14C-ring labelled pesticide, laboratory studies under aerobic and anaerobic conditions were conducted. 14C-activity in solutions was directly determined by liquid scintillation counting. Unextractable soil residues were determined by combustion. The nature of methanolic '4C-residues was determined by thin layer and high performance liquid chromatographic analysis. Results Under aerobic conditions 10%-14% of applied dose was mineralized during 90 d irrespective of soil type. The soil extractable pesticide residues decreased with time and the bound residues gradually increased. The highest binding capacity of about 26%-29% was observed in clay soil under aerobic conditions after 90 d. A good balance sheet was obtained and the percentage recovery was generally between 91% and 100%. Conclusion The mineralization of 2,4-d in clay soil was higher than that in clay loam soil under anaerobic conditions. Under aerobic conditions, the soil type had no influence on mineralizaion capacity of 2,4-d during 90 d. The soil binding increased with time whereby the extractable 14C-residues simultaneously decreased. Chromatographic analysis of the methanol extractable l4C-residues of soils revealed the presence of 2,4-d as a main product together with 2,4-dichlorophenol.

关键词： 14C-ring labelled Organochlorine pesticide Egyptian soil Radiochemicals

An old issue and a new challenge for nuclear reactor safety

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2021年第4期15卷 854-859页

作者： F.d’AURIA University of Pisa DESTEC/GRNSPG–L.go L.Lazzarino 256100 PisaItaly

Nuclear reactor safety(NRS)and the branch accident analysis(AA)constitute proven technologies:these are based on,among the other things,long lasting research and operational experience in the area of water cooled nuclear reactors(WCNR).Large break loss of coolant accident(LBLOCA)has been,so far,the orienting scenario within AA and a basis for the design of *** incomplete vision for those technologies during the last few years is as follows:Progress in fundamentals was stagnant,namely in those countries where the WCNR were *** became evident,noticeably in relation to nuclear fuel under high *** estimate plus uncertainty(BEPU)techniques were perfected and available for *** and informatics systems were in extensive use and their impact in case of accident becomes more and more un-checked(however,quite irrelevant in case of LBLOCA).The time delay between technological discoveries and applications was becoming *** present paper deals with the LBLOCA that is inserted into the above *** conclusion is that regulations need suitable modification,rather than lowering the importance and the role of ***,strengths of emergency core cooling system(ECCS)and containment need a tight link.

关键词： large break loss of coolant accident(LBLOCA) nuclear reactor safety(NRS) licensing perspectives basis for design of water cooled nuclear reactors(WCNR)

Preparation and characterization of colloidal dispersions of graphene-like structures from different ranks of coals

在线全文

学校读者我要写书评

暂无评论

燃料化学学报 2017年第8期45卷 897-907页

作者： d.P.Savitskii Institute of Biochemical Technology and Nanotechnology RUDN University

This paper focuses on preparation of colloidal solution of graphene-like structures from different ranks of coals: brown coal,bituminous coal,low-volatile bituminous coal,anthracite. It was found that brown coal thermo-oxidative destruction leads to formation of small d = 32 nm( V = 17%) and large d = 122 nm( V = 11%) fractions of nanoparticles. The thermo-oxidative destruction of bituminous coal leads to formation of nanoparticles d = 50 nm( V = 5.2%) and d = 164 nm( V = 16%). Thermooxidative destruction of low-volatile bituminous coal and anthracite leads to formation of nanoparticles,predominantly,d = 122-190 nm. Carbon nanostructures obtained from coal are negatively charged at pH= 2-12. Colloidal solution of carbon nanostructures at dispersed phase concentration 0. 01 mg/mL is stable for 1 month. Electron diffraction patterns and X-ray analysis of carbon nanostructures showed that nanostructure from brown coal is amorphous and nanostructure from anthracite is crystalline. Results of coal macromolecules modeling and graphene-like structures obtained from them are presented.

关键词：象 graphene 一样结构煤胶体的分散粒子尺寸分发 electrokinetic 潜力

Exploring effects of property variation on fragmentation of metal rings using a simple model

在线全文

学校读者我要写书评

暂无评论

defence Technology（防务技术） 2023年第5期23卷 1-7页

作者： J.d.Robson department of Materials The University of ManchesterManchesterM139PLUK

A simple finite element implementation of the Mott model for fragmentation of a thin walled ring has been implemented and used to explore the effect of local variations in fracture strain around the *** model has successfully reproduced the fragment size distributions previously reported,which follow a characteristic“Mott distribution”form,providing sufficient(1000)simulations are *** has been shown that this form is retained even when there are large differences in the random distribution of fracture strains or a different choice of function used to describe the fracture strain *** these cases,the strain rate has a much stronger effect than fracture strain distribution the on the average fragment size and fragment ***,for cases where there are a small number of local defects that strongly reduce the fracture strain at certain locations around the ring,the predicted fragment size distribution develops a bimodal *** is also the case for large but gradual variations in fracture strain with position around the *** results have implications for cases where a small number of large pre-existing defects exist,or processing has led to macrozones in the *** utility of a simple fast running model to study these cases is discussed.

关键词： Fragmentation Mott model Property variation

Effects of jute fibre content on the mechanical and dynamic mechanical properties of the composites in structural applications

在线全文

学校读者我要写书评

暂无评论

defence Technology（防务技术） 2020年第6期16卷 1098-1105页

作者： Suhad d.Salman Mechanical Engineering department College of EngineeringMustansiriyah UniversityBaghdadIraq

due to notable characteristics,sustainability concept and environmental issues,hybridisation natural with synthetic fibres to fabricate composites have been rapidly gaining market share in different applications(structural,military,aerospace and automotive vehicles).Compression,tension and fatigue tests of various stacking sequences of plain jute/carbon reinforced(PVB)polyvinyl butyral by hot hydraulic press technique were experimentally *** types of fabricated composites with various constituents(jute,carbon and their hybrids)were fabricated and ***,fatigue lifetime of hybrids increases with increasing the carbon content relative to the jute fibre *** the other hand,Jute composites possess high strain compared to pure carbon composite,which gives an overall improvement in mechanical ***,H1 hybrid with Carbon/Jute/Carbon sequences offers similar fatigue stiffness behaviour of H3 hybrid with Carbon/Jute/Carbon/Jute sequences when subjected to cyclic *** composite(C)exhibited the highest fatigue resistance,whiles jute composite(J)possessed the highest strain and semi brittle trends in both mechanical and fatigue *** concluded that plain jute fibres could partially replace high-cost synthetic carbon fibres to produce more eco-friendly hybrids to be utilised in different composites industries.

关键词： Plain woven jute Carbon fabric Hybrid composite Mechanical Cyclic loading Morphological Fatigue properties

A Hybrid Joining Technology for Aluminum/Zinc Coated Steels in Vehicles

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2010年第9期26卷 858-864页

作者： C.Y.Choi d.C.Kim d.G.Nam Y.d.Kim Y.d.Park School of Materials Science and Engineering Pusan National UniversityBusan Advanced Welding & Joining R&d division Institute of Industrial Technology Incheon dongnam Technology Service division Korea Institute of Industrial TechnologyBusan department of Advanced Materials Engineering Dong-Eui UniversityBusan

Currently,in the automotive industry,joining of the aluminum alloys with the steel is a crucial problem to be *** joining techniques including resistance spot and gas metal arc welding are not acceptable for those applications due to a number of metallurgical *** investigation was carried out to develop the hybrid joining process combining the resistance spot welding and *** this study,an attempt was made to apply hybrid process to the joining of dissimilar sheet metals,Al-Mg-Si（6000 series） alloy and low carbon steel *** process（resistance spot weld/brazing） using filler metal was found to be effective to overcome the incompatibility between aluminum alloy and *** hybrid joining process of Al alloy sheet and steel sheet did not produce acceptable bond strength,it was proved to have reasonable interfacial bond layer if the optimal process condition was applied.

关键词： Hybrid joining Aluminum alloy Steel Resistance welding Brazing