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1.
《文物保护研究》2013,58(3):179-190
Abstract

Testing of chemical stabilization treatments and desiccated and anoxic storage microclimates for the protection of archaeological iron stored in unsuitable climatic conditions was carried out by the conservation department of the Japanese Institute of Anatolian Archaeology at the Kaman-Kalehöyük excavation in Turkey. The chemical stabilization treatments involved alkaline sulfite, barium hydroxide and sodium hydroxide. Environmental stabilization was explored using RP-A oxygen scavengers in Escal® bags as part of the Revolutionary Preservation System (RP System®) manufactured by Mitsubishi Gas Chemical Company, Inc. The efficiency of the chemical treatments was examined by comparison with mechanically cleaned iron objects. The efficiency of the storage systems was determined by comparing the chemically and non-chemically treated objects in the RP System® using RP-A scavengers and in polyethylene ziplock bags containing silica gel. The efficiency of these treatments and storage systems was examined and assessed at Kaman after a period ranging from 7 to 9 years. The anoxic and desiccating properties of the RP System® resulted in superior protective qualities over polyethylene bags with silica gel. The RP System® compensated for inadequate chemical stabilization and protected iron that had not been chemically stabilized.  相似文献   

2.
ABSTRACT

The impact of solvent vapour from two solvents, acetone and industrial denatured alcohol (IDA), commonly used in adhesive reactivation in textile conservation, when applied to artificially soiled silk fabric through either Gore-Tex® or Reemay® membranes for exposure times of either 1 or 3 min, was measured using microscopy and ImageJ to monitor the movement of the solid particulates of the soiling, and Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR) to monitor the movement of the oily components. Analysis using these techniques successfully showed the movement of large particulates through the textile and a decrease in the presence of oil. Analysis with FTIR-ATR showed that the application of solvent vapour by a poultice method produces more than just a surface change and the vapour can penetrate far enough into the fibres to cause a change in the level of oil through the entire textile. The results showed that the solvents and barrier membranes have characteristic differences which impact on the changes on the soiling. The application of acetone produced a greater change in the movement of oil on the front and back of the samples than the application of IDA, while a comparison between the barrier membranes showed a greater change occurring in the level of oil with the use of Gore-Tex® rather than Reemay®. The time of exposure to solvent vapour made little difference to the changes to the textile soiling. Quantitatively significant results were gathered from analysis of the changes in the oil measured with FTIR-ATR, and qualitative changes in the large particulate soiling, demonstrating the potential usefulness of ImageJ open access software in future historic textile soiling monitoring studies.  相似文献   

3.
Lead white is widely used as a white pigment in the history of Persian painting. This paper focuses on three Persian treatises dated between the twelfth and the sixteenth century, which explained different manufacturing methods of lead white or sefidāb-i-sorb. Experimental reconstruction of each recipe to access the comprehensive meaning of the text and analytical studies with X-ray powder diffraction on products of recipes revealed white compounds other than the previously known products of hydrocerussite (Pb(OH)2?·?PbCO3) and cerussite (PbCO3) in samples. Chlorine-containing raw materials mentioned in these recipes lead to the chemical products of laurionite (Pb(OH)Cl), blixite (Pb8O5(OH)2Cl4), and phosgenite (Pb2Cl2(CO)3) in the final products. These data lead to the hypothesis of the discrepancy of the lead white pigment between Iran and Europe and a marked probability of other compounds in historic Persian lead white samples.  相似文献   

4.
《文物保护研究》2013,58(3):191-215
Abstract

Fumigant effects on protein-based materials were examined and compared with those of non-chemical pest-eradicating measures. The responses to six fumigants – methyl bromide, methyl iodide, ethylene oxide, methyl bromide/ethylene oxide mixture, propylene oxide and sulfuryl fluoride – were examined with two controlled atmospheres and a range of thermal treatments, using protein electrophoresis, Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermal microscopy (Tmic), thermal gravimetric analysis (TGA), amino acid analysis and X-ray fluorescence (XRF) spectrometry. A model soft-tissue protein, freeze-dried chicken muscle, was shown to be affected by some fumigants, especially methyl bromide, methyl iodide and sulfuryl fluoride (Vikane®). This is the first detailed evidence of chemical alterations of a protein material by fumigants under the common treatment conditions for museum use, especially showing a possibility of protein modification by purer grade sulfuryl fluoride whose definite mechanism of toxicity is still unknown. Residual bromine and iodine were clearly detected by XRF in the muscle specimen that had been fumigated with either methyl bromide or methyl iodide respectively, even after a single fumigation several years earlier. On the other hand, significant change in characteristics of animal glue and new and deteriorated silk textiles were not detected. However, residual bromine and occasionally iodine also were detected in the glue and silk samples fumigated by methyl bromide or methyl iodide several years earlier.  相似文献   

5.
Transaction logs from online search engines are valuable for two reasons: First, they provide insight into human information-seeking behavior. Second, log data can be used to train user models, which can then be applied to improve retrieval systems. This article presents a study of logs from PubMed®, the public gateway to the MEDLINE® database of bibliographic records from the medical and biomedical primary literature. Unlike most previous studies on general Web search, our work examines user activities with a highly-specialized search engine. We encode user actions as string sequences and model these sequences using n-gram language models. The models are evaluated in terms of perplexity and in a sequence prediction task. They help us better understand how PubMed users search for information and provide an enabler for improving users’ search experience.  相似文献   

6.
The Winsor & NewtonTM (W&N) nineteenth century archive database includes digitised images of hand-written instructions and workshop notes for the manufacture of their artists’ materials. For the first time, all 183 production records for yellow lead chromate pigments were studied and evaluated. They revealed that W&N produced essentially three pigment types: lemon/pale based on mixed crystals of lead chromate and lead sulphate [Pb(Cr,S)O4]; middle on pure monoclinic lead chromate [PbCrO4]; and deep that contains the latter admixed with basic lead chromate [Pb2CrO5]; accounting for 53, 22, and 21% of the production, respectively. Production records for primrose (4%) were also included since the formulation results in mixed crystals with a high percentage of lead sulphate, which, according to the literature, leaves it more prone to degradation. Each pigment type is characterised by only one or two main synthetic pathways; process variations reveal a systematic and thorough search for a high-quality durable product. A comparison of the chemical composition of pigment reconstructions with early W&N oil paint tubes showed that their records entitled ‘pale’ and ‘lemon’ correlated with the pigment in their tube labelled chrome yellow and, ‘middle’ and ‘deep’ with the label chrome deep. Lemon and middle pigment formulations were made into oil paints to assess their relative photo-stability. The degradation process was followed by colorimetry and was studied by synchrotron radiation-based techniques. Based on the X-ray absorption spectroscopy data, the possibility for creating a stability index for chrome yellows is discussed.  相似文献   

7.
《文物保护研究》2013,58(4):217-226
Abstract

Many natural and synthetic products have been used for the consolidation of paint layers, but none have been thoroughly tested for this application. This is apparent for most of the synthetic and semi-synthetic adhesives for conservation, many of which are pure polymer resins and dispersions adapted from other industries. They were not specifically formulated with the appropriate properties for conservation, nor do they take advantage of some of the more recent developments in adhesive technology. BEVA® 371 is unique among adhesives used for consolidation treatments, as it is a multi-component mixture and was designed specifically for the conservation field using the best technology available at the time. However, the main focus of the research was its application as a lining adhesive. Thus, optical properties and stability, specifically color stability, were not thoroughly evaluated even though some lining applications that were first recommended could have benefited from this type of investigation. This paper will discuss the development of BEVA® 371, the chemistry, and roles of each component, and address a practical concern about the tack behavior of its replacement formulation, BEVA® 371b.  相似文献   

8.
This paper examines the effect of modifiers on the stability of a vinyl acetate/ethylene copolymer dispersion adhesive upon aging. Eighteen common modifiers were added to a well-characterized vinyl acetate/ethylene copolymer dispersion (Dur-O-Set® E-150) in known concentrations and dry-film samples were subjected to 16–17 years of dark aging and seven to eight years of light aging. Yellowing, pH, gloss, swelling, cohesive strength, and flexibility were monitored for changes upon aging. Generally, the neat Dur-O-Set® E-150 (no additives) was found to become acidic on aging, but was fairly resistant to yellowing. It also swelled substantially in toluene, was of high gloss, medium strength, and flexible, and remained so on aging. No modifier was found to improve these properties. Various solvents, wetting agents, and thickeners did not alter the properties by much, while plasticizers, freeze-thaw stabilizer, glycerin, and certain fillers had a more negative effect.  相似文献   

9.
《文物保护研究》2013,58(4):281-297
Abstract

Cellulose poultices are frequently used in stone and wall painting conservation for the purposes of soluble salt extraction, consolidation and cleaning. They have the reputation of being easy and pleasant to work with, have a neutral pH, high water absorption and plasticity, exhibit good conformance and adhesion to the substrate, and in most cases leave minimal residues after clearance. The cellulosic materials from which they are composed range from cotton wool, blotting paper or newspaper, to cellulose powders, the latter now by far the most common form of cellulose used today by conservators. Drawbacks of these products include poor water retention when applied to vertical surfaces, a tendency to redistribute salts further into the object substrate, and poor long-term treatment effectiveness for salt extraction. Hence cellulose poultices are used frequently due to good working properties, but apparently are in some situations not very effective. In this paper, existing knowledge of these poultices is outlined, followed by investigations undertaken to fill some of the knowledge gaps. Investigations include characterization of poultice properties such as pore size distribution and workability, and of moisture transport processes within poultice/substrate systems including moisture penetration depth, moisture distribution, and poultice shrinkage during drying. Cellulose powder products known under the trade name Arbocel®, extensively tested and used in conservation over several decades, were a particular focus. Resulting guidelines include counter-intuitive measures such as (when used for salt extraction purposes) the use of thinner poultices to reduce drying shrinkage and salt redistribution further into the substrate. The relatively uniform pore size distribution (around 10 μm) of Arbocel® poultices makes them more appropriate for salt extraction on substrates with a medium-coarse pore size (i.e. 15 μm and above), while on fine porous substrates (10 μm and below), the extraction will not be as efficient.  相似文献   

10.
ABSTRACT

The authors of this article analyzed the differences in output when searching MEDLINE direct and MEDLINE via citation management software, EndNote X1®, EndNote Web®, and RefWorks©. Several searches were performed on Ovid MEDLINE and PubMed directly. These searches were compared against the same searches conducted in Ovid MEDLINE and PubMed using the search features in EndNote X1, EndNote Web, and RefWorks. Findings indicated that for in-depth research users, should search the databases directly rather than through the citation management software interface. The search results indicated it would be appropriate to search databases via citation management software for citation verification tasks and for cursory keyword searching.  相似文献   

11.
《文物保护研究》2013,58(3):134-142
Abstract

Naturally occurring pigments used by Aborigines in rock paintings have been collected in Western Australia. They area red pigment (mainly hematite, Fe2O3)(from a red ochre mine worked until historic times by Aborigines, and a white pigment (huntite, Mg3Ca(CO3)4) which is still collected and used by Aborigines. Samples were also taken from rock paintings in which these pigments were used or were thought to have been used. The pigment samples were analysed to establish chemical, mineralogical, and physical properties. The paint samples were examined microscopically and with an electron probe to study their relationship with the rock surface and with other paint layers. The relationship between the pigments’ properties and their durability is discussed.  相似文献   

12.
Pigments on a figurative wall painting in Poudeh village, central Iran, were analysed by micro X-ray fluorescence spectrometry, micro Raman spectroscopy, scanning electron microscopy coupled with energy dispersive X-ray spectrometry, micro Fourier transform infrared spectroscopy, X-ray diffractometry, and polarised light microscopy. Red lead, ultramarine blue, chrome yellow, brass powder, white huntite, and lammerite (Cu3(AsO4)2) were identified as red, blue, yellow, golden, white, and green pigments, respectively, while gypsum and barite were used as extender. In addition, glushinskite (MgC2O4·2H2O) was identified as a deterioration product of white huntite. Moreover, several analytical studies suggested that lammerite was a degradation product of emerald green (Cu(CH3COO)2·3Cu(AsO2)2) originally used as green pigment in the painting. The formation of lammerite is suggested to be due to the migration of arsenic throughout the paint layer. Based on the pigments identified, the wall painting is dated from the mid-nineteenth century to the mid-twentieth century.  相似文献   

13.
This paper investigates the effectiveness of using MeSH® in PubMed through its automatic query expansion process: Automatic Term Mapping (ATM). We run Boolean searches based on a collection of 55 topics and about 160,000 MEDLINE® citations used in the 2006 and 2007 TREC Genomics Tracks. For each topic, we first automatically construct a query by selecting keywords from the question. Next, each query is expanded by ATM, which assigns different search tags to terms in the query. Three search tags: [MeSH Terms], [Text Words], and [All Fields] are chosen to be studied after expansion because they all make use of the MeSH field of indexed MEDLINE citations. Furthermore, we characterize the two different mechanisms by which the MeSH field is used. Retrieval results using MeSH after expansion are compared to those solely based on the words in MEDLINE title and abstracts. The aggregate retrieval performance is assessed using both F-measure and mean rank precision. Experimental results suggest that query expansion using MeSH in PubMed can generally improve retrieval performance, but the improvement may not affect end PubMed users in realistic situations.  相似文献   

14.
Mobile devices facilitate the use of mobile services that are similar to services used via fixed Internet connections. The objective of this article is to assess displacement effects between fixed and mobile Internet services, and to research the role of technical capabilities of mobile handsets and demographics as moderators. This study is based on a sample of 628 respondents who have access to fixed and mobile Internet services. The respondents' usage of services was analyzed. An online questionnaire was used to collect data on the use of information, communication, entertainment, and transaction services. Mobile Internet reinforces, rather than replaces, Internet usage. When people possess an iPhone® or (mobile) laptop, this reinforcement effect is present for entertainment services. With respect to transaction services, the Blackberry® makes a stronger case. With the exception of gender, demographic characteristics do not have a moderating effect. Women display a stronger reinforcement effect than men in relation to transaction services. To the best of our knowledge, no study to date has investigated the displacement effects of fixed Internet services by the mobile handset. This empirical study contributes to the literature regarding the displacement effects of mobile Internet services.  相似文献   

15.
《文物保护研究》2013,58(3):199-210
Abstract

Descente des vaches (1836) by Théodore Rousseau in the Mesdag Collection in The Hague is barely readable and its paint layers are in poor condition. The surface of the painting is strongly deformed and cracked, the whole painting has darkened and especially the greens have lost all or most of their colour resulting in brown passages. Large passages of the painting that were painted with multiple thick and medium-rich layers have darkened dramatically. This paper proposes that the degradation of Emerald green (Cu(C2H3O2)2·3Cu(AsO2)2, copperacetoarsenite) – the main green pigment used in this painting – is a significant factor in the cause of the darkening. Electron backscatter images reveal that the Emerald green particles are shown different degrees of degradation: from partially to completely disintegrated. Elemental maps show that arsenic is distributed throughout the paint cross section, with relatively higher concentrations around iron- and aluminium-containing particles, and in the varnish layer. Imaging-Fourier-transform infrared microscopy detects copper soaps in the degraded Emerald green-containing layers. Analytical data from four paint cross sections strongly suggest that Emerald green reacts with free fatty acids derived from the binding medium forming copper soaps and mobile arsenic-based species. Chemical laboratory experiments fully support this hypothesis. Emerald green and palmitic acid in chloroform form copper palmitate and arsenic trioxide (arsenolite, cubic) under room temperature and normal light conditions. The degradation of Emerald green particles in Descente des vaches has resulted in a loss of light-reflecting surfaces and in newly formed compounds in the paint, both contribute to the colour change from green to brown.  相似文献   

16.
《文物保护研究》2013,58(4):289-303
Abstract

A tube-type passive sampling method has been developed and assessed for the quantification of formaldehyde (methanal) vapours in indoor air. The sampler was designed for use in museums where test sites often include small enclosures with low air movement. The procedure involves collection of formaldehyde vapours in a Palmes diffusion tube containing a paper support impregnated with an acidified solution of 2,4-dinitrophenylhydrazine (2,4-DNPH). After sampling, quantification of the trapped F-DNPH is achieved by high performance liquid chromatography (HPLC) analysis with UV detection at 350nm. To validate the procedure, permeation devices were used to generate formaldehyde-containing atmospheres, 81–2975ppb, in a 20dm3 chamber so that experimentally derived sampling rates could be calculated and compared with the theoretical value. Three 2,4-DNPH solutions were investigated to obtain an efficient and stable trapping solution. Best results were achieved with a 27mg.ml?1 solution of 2,4-DNPH which contained 4·5%v/v orthophosphoric acid. At 55% RH, and with low airflow in the chamber, the experimentally derived sampling rate of 1·34 ± 0·17ml.min?1 was in good agreement with the theoretically derived sampling rate of 1·36ml.min?1 The passive sampling method was repeatable and reproducible with RSD (relative standard deviation) values below 7%for long-term exposures at low air velocities.  相似文献   

17.
There is an overall perception of increased interdisciplinarity in science, but this is difficult to confirm quantitatively owing to the lack of adequate methods to evaluate subjective phenomena. This is no different from the difficulties in establishing quantitative relationships in human and social sciences. In this paper we quantified the interdisciplinarity of scientific journals and science fields by using an entropy measurement based on the diversity of the subject categories of journals citing a specific journal. The methodology consisted in building citation networks using the Journal Citation Reports® database, in which the nodes were journals and edges were established based on citations among journals. The overall network for the 11-year period (1999–2009) studied was small-world and followed a power-law with exponential cutoff distribution with regard to the in-strength. Upon visualizing the network topology an overall structure of the various science fields could be inferred, especially their interconnections. We confirmed quantitatively that science fields are becoming increasingly interdisciplinary, with the degree of interdisplinarity (i.e. entropy) correlating strongly with the in-strength of journals and with the impact factor.  相似文献   

18.
Although young citizens may not always politically engage in the same fashion as their elders, research suggests they are using Facebook, Twitter, and other newer communication systems to mobilize politically both generally and around environmental issues. Given the declining environmental conditions facing young citizens, a national stratified quota sample of 1,096 U.S. parents and their children between the ages of 12 and 17 was conducted to investigate the factors potentially related to their efforts to persuade members of their online social networks to be more environmental. We believe that online peer persuasion is an important concept to investigate because peer persuasion can create subjective norms that ultimately may influence behavior. Hierarchical regression analysis revealed that, although parents influence youth behavior (Adj. R 2 = .11), the greatest variance in behavior was explained by the youth's own environmental self-efficacy, environmental news consumption, political interest, time spent online, gender, and environmental consumerism (ΔR 2 = .29). Youth political interest and environmental consumerism were especially important variables in the final model. Structural equation modeling reinforced that parental influence is primarily indirect. This study appears to be among the first to link environmental consumerism with youth online peer persuasion.  相似文献   

19.
Photos of demonstrations in Egypt have been overwhelmingly used in online news since the revolution of January 25, 2011. This article explores the visual aspects of demonstration photo albums during the political conflicts in Egypt that led to two Egyptian revolutions.11 This article adopts the term “revolution” because the new Egyptian Constitution issued in 2014 described events of January 25, 2011, and June 30, 2013, as revolutions.View all notes It scrutinizes the different types of photo albums, considers the differences and similarities between photo album frames and still photograph frames, and implements syntagmatic analysis of demonstration albums. The article concludes that visual framing occurs through nonchronological and sequential syntagmas.  相似文献   

20.
Arthur Hezlet's Electronics and Sea Power (New York: Stein & Day, 1975—$15.00)

W.M. Dalton's The Story of Radio (London: Adam Hilger Ltd., 1975—about $9.00 for each of three volumes)

Anita Klever's Women in Television (Philadelphia: Westminster Press, 1975—$5.95)

Donald L. Guimary's Citizen's GrouRs and Broadcasting (New York: Praeger Special Studies, 1975—$14.00)

John Blair & Co.'s Statistical-Trends in Broadcasting 1975: 11th Edition (New York: John Blair & Co., 1975—$2.50, paper)

Natan Katzman's Public Television Program Content: 1974 (Washington: Corporation for Public Broadcasting, 1975—price not given, paper)

James W. Brown (ed.) Educational Media Yearbook: 1975-76 (New York: R.R. Bowker, 1975—$21.95)

Alan Bermingham et al. The Small TV Studio: Equipment and Facilities (New York: Hastings House, 1975—$7.95, paper)

John H. Barwick and Stewart Kranz's Profiles in Video: Who's Using Television and How (White Plains, N.Y.: Knowledge Industries Publications, 1975— $27.50)  相似文献   

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